CA2248828A1 - Vibration and shock attenuating articles and a method of attenuating vibrations and shocks therewith - Google Patents

Abstract

The present invention relates to a vibration attenuating article (58, 62, 70, 74, 80, 86) that has a non-tacky film (54, 60, 66, 72, 78, 84) covering enclosing all or a significant portion of the surface of a vibration attenuating material, wherein at least a portion of the vibration attenuating surface covered by the film covering is a three-dimensional surface. A layer of adhesive must be present on at least a portion of the exterior film covering when all of the vibration attenuating material is covered by the exterior film covering.

Description

VIBRATION AND SIIOCK Al-l~;NUATING ARTICLES AND A METHOD
S OF AI~ENUATING VIBRATIONS AND S~IOCKST~IEREWlT~I

Field of the Invention The present invention relates to a one-piece vibration ~tteml; ~in~ article thathas a non-tacky film covering enr,losin~ all or a ci~lifit ~nt portion of the surface of a vibration ~ttçml~ting material, w~,ein at least a portion of the vibration ~ttçnU~tin~ material's surface covered by the film covering is a three dim~pn~ion~l surface. The articles can be used in numerous applications where vibration or shock ~tt~nu~tion is required, inclu~ling, but not limited to, disk drive applications, automotive applications, and electronics applications.

Bal k~round of the Invention Vibrations and/or shocks can excite resonant frequPncies in structures.
Damping and/or isolation can be used to reduce the vibration and shock effects.
Applications where vibration and shock control are particularly hl~ ol lanl include disk drive applications, actuator voice coil motor applications, computer shock isolation applications, car applications, shock isolator applications for drawers or doors, and the like.
As a specific example, resonant vibrations or shocks in a disk drive can be caused by the read-write actuator voice coil motor assembly. An actuator is used in a disk drive to very quickly and p~ec;sely position the read/write element over the data track of a spinning disk. The actuator voice-coil motor design most often used to position the tr~n~ducPr can often generate vibrations that lead to excessive acoustical noise that is irritating to users of the disk drive. These vibrations can also impair the positioning or stability of the read-write tr~n~ducPr over the desired data track, thus redur.ing the drive's performance.
Fig. 1 illustrates a partial exploded view of a disk drive with only a few key features shown for clarity. Fig. l shows top cover 2, a bottom cover 4, and a top , ................................... . . ...... . .

WO 97/38237 PCTtUS97/05827 - m~netic plate of the voice coil motor 6. A damper which would be used to damp vibrations within the disk drive could be positioned on the top magnetic plate of the voice coil motor 6. The damper location is intlic~ted as 8. A more detailed description of a disk drive and actuator voice coil motor is found in U. S. Patent No.
5,224,000.
One method of damping such an actuator is to use a damper which is a die cut part of damping material that is placed in key areas which experience vibration to add damping to the actuator motor assembly. (See Fig. 2 where the die cut part of d~mping material is represented by 10, the top cover of the disk drive is 2, and the top magnetic plate of the voice coil motor is 6.) Typically, the damper is placed b~;Lween a portion of the motor assembly and an outer surface, such as the drive's cover or base. Known d~"~el ~ often use a damping material with a tacky surface ~soci~ted with the polymer that can make their use difficult.
Known die cut dampers are typically from 0.025mm (lmil) thick to over 3.81mrn (150 mils) thick. These die cut dalllpel~ have ess~nti~lly flat top and bottom surfaces and straight die cut side edges that are ess~nti~lly perpen~icul~r to the top and bottom surfaces of the damper. The vibration damper may optionally have a polymeric film layer, for example, a die cut piece of polyester or polyethylene film, att~hed to the damper with a p,css~re sensitive adhesive. Theadd on polymeric film covers only the top portion of the flat top damper. This polyrneric film layer can be the same size as the damper top surface area or extend past the top surface edges. (See Figs. 2a and 2b, respectively. ln Fig. 2a the polyethylene film is 16, the pressure sensitive adhesive is 14, the damping material is 12, the disk drive cover is 2, and the top m~gnP~tic plate ofthe voice coil motor is 6.
In Fig. 2b the polyethylene film is 22, the pressure sensitive adhesive is 20, the damping material is 18, the disk drive cover is 2, and the top m~netic plate of the voice coil motor is 6.) Neither the surface of the film in contact with the damper, nor the damper surface with which the film is in contact, is three dimensional. The films do not offer any significant damping benefit as compared to the damping material and the main benefit the film does provide is to provide a tack-free surface , . , W 097138237 rCT~U~97/05827 on a single flat surface of the damper that will not bond to other surfaces it contacts.
Two-piece "damping" constructions that use a damper and a separate die cut film part have been used in disk drive systems where a damper (a die cut section of darnping polymer) has a film (a polyethylene polymeric film with a pres~ e sensitive adhesive on one side) ~ttr~ to a surface opposite from that which the damper is placed on, such that when the drive is assembled, the damper and film are in contact (See Fig. 2c, wl~elein the polyethylene polymeric film is 26, the pressure sensitive adhesive is 28, the d~ polymer is 24, the top cover of the disk drive is 2, and the top m~gn~tic plate ofthe voice coil motor is 6). The film provides a surface to which the damper will have a fairly weak bond so that the drive can be easily opened and reworked. The surface of this film in contact with the damper is not three dimensional, nor does it contact a three ~limPnciQnal surface of the damper.
Summan of the Invention These known dampers provide for significant redllctiorlc in ~Col~ct~ noise as well as vibration levels. However, problems with these known dampers include the inability to use low Tg d~mring materials effectively because they may be tacky at room t~ pe~L~Ire or at disk drive use te,,.l).,.~LLIres. Additional problems with the current d~llpel~ include poor o lt~Ccing~ difficulty in d;.ll~.-;on~l control, etc.
These and other problems are expanded upon in detail hereafter:

1) Known dampers not used in conjunction with a polymeric film attached opposite the dampers (See Fig. 2 ) can build a strong bond to the surfaces they come into contact with (such as such as the cover or base surface of a drive). This makes reworking of the drive difficult as the drive may be difficult to reopen due to the strong bond which may have been formed.

2) A damper that has a film ~tt~hment coextensive with the top surface of the damper, can experience "blooming" whereby the damping polymer eyr~n~ls past WO 97/38237 PCT~US97/05827 - the edge of the film during use crealing a situation where the dq-mping polymer can still create a significant bond in an undesired location. When co.,.pressed intoposition, the damping polymer expands around the film allowing a bond to form toan undesired surface (See Fig. 2d wherein the polymeric film is 30, the pressuresensitive adhesive is 32, and the ~ ping polymer is 34). Using thicker films to limit this is not practical for thick dampers and could make the dampers difficult andmore costly to m~nllf~chlre 3) Dampers with a polymeric film (such as a polyester film) extended over the edges of the damper (See Fig. 2b) are difficult to handle and costly to mqnllf~ctllre as the larger film is die cut and ~tt~cl-ed via pres~u,e sensitive adhesive to the damper or the damper is pre-cut and subsequçntly ~tt~hed via pres~ure sensitive adhesive to the film.

4) Dampers that use a separate film die cut part attq-~hed to an opposite surface in the drive (to prevent high degree of bonding) prior to asselllbly of the drive require an additional part to mqmlf~ct~lre and apply to the drive (See Fig. 2c).

5) Often low Tg damping materials have a tacky surface associated with the damping material, unless a s -fficient degree of crosclinlrin~ is present in the polymer to render them tack-free. The polymers that have been rendered tack-free by highlevels of crosclinking (greater than or equal to about 0.5%) have a higher rubbery region modulus than a similar polymer not so highly crosslinked. The me~hqnical strength of the damping polymer may also be reduced due to the high level of cross!in'-ing These highly crosslinked tack-free polymers will not stress relax as quickly or to as low a level as less highly crosslinked dal"~)ing polymers. This retention of stress in highly crosslinked polymers is d~l- ill~el~lal in applications where the damper is initially stressed upon application and to function prope- Iy, the damper needs to stress relax (e.g., over the range of thickness stack-up assembly tolerances for the actuator motor assembly, the high crosclinked or high Tg damping polymer may not - have sufficient relaxation in the polymer to prevent cover bowing once the cover is att~çhçd to the base of the drive and the damper is COIII~ ssed). A tack-free d~mring polymer may not meet all the application needs as the presence of crosslinking may reduce the peak d~ of the dd~.,ping polymer at both room and opelalillg telllpelal~res~
In addition, these dampers require a pressure sensitive adhesive to aid in att~çhinp: the damper to the drive since the d~mring polymer is not tacky.

6) The current dampers which tend to be tacky at 25 to 65~ C (See Figs. 2, 2a, 2b, and 2c) can collect cor.~ tion easily and are difficult to clean either by hand or via automatic cle~ning systems.

7) Current dampers (See Figs. 2, 2a, 2b, and 2c) can have a high degree of ol~t~ ing This can be a problem for the enclosed en~,iro~ enl of the disk drive where o~lt~eed materials can lead to drive reliability problems. The current da",pe, ~ have a significant exposed surface area inside the drive and are often the largest source of organic material in the drive. Current dalnl)el ~ may be pre-outgPc~ed in an oven by heating the dampers to an elevated telllpe,~ re for a period oftime. But this adds cost and complexity to the m~nll~ctllring process, 20 inçl~.din~ the potential for the dampers to become conl~;n~ted 8) The current dampers (See Figs. 2, 2a, 2b, and 2c) can be difficult to handle as plerel,ed damping polymers tend to be somewhat tacky at room tenlpelal~lre and most are tacky at drive opelaling ten-pela~llres. .AIltom~ted pl~cem~nt o~such dampers can be difficult and costly due to the d~"~cl's tacky characteristics .

9) The shapes of the current pl efel I ed dall"~c. s (See Figs. 2, 2a, 2b, and 2c) are limited as a die cutting process is used to attain the length (X) and width (Y) of the damper. The material used for the damper, especially as the construction becol"es thicker and the polymer tacky, can be difficult to remove from the excess W O 97/38237 PCTnUS97/05827 ing material after die cutting. This excess r~mping material, or "weed", removal problem can limit the dampers' shapes. Dampers of square and re~ g~ r shapes can be obtained, but other shapes such as round, tri~n~ r or "peanut't shapes can be difficult to obtain as the damper th;~l~ness increases. Sharp co-,.ered or small radius dampers are also very difficult to m~mlfacture and can limit thedarnpers aspect ratio for thickness versus X or Y d -....l.- ;on and also corner radius tolerances. Dimensional control of length and width is more difficult as the damper becomes thicker and tolerances that can be held become greater as the die cut damper becomes thicker.

10) The exposed damping polymers of a damper can be o~citli7ed at elevated te~l~pe~alule for short times or medi~lm te".pe-~ res at long times. Oxidation can change the damping pl ope- lies of the damper and decrease the benefit of the damper.

11) The exposed damping material of a damper can be exposed to harsh en~il o~ from the air or solutions it may come into contact with during m~mlf~ctllre or use. These harsh medillrn5 can react ~,vith the damping polymer to reduce the benefit of the damper. In addition, reaction~ between the damping material and the harsh en~dlol~"~ can create secondary organic compol1e,.l~ thathave a negative effect on other materials near the dampers use. Furthermore, components or agents used in the damping material m~mlf~ct~1re may escape from the damper and have negative effects on materials near the damper's use location.
For cA~ll~le, if the damping material uses a catalyst that can be leached from the cl~mping material, it can cause del,in.e.~lal reactions to occur elsewhere in the area near the damper's use location. For e,.~"ple, a component that leaches or outg~cses onto the storage disk's surface from the damping material could lead to corrosion of the disk surface area.

12) The exposed damping material of current dampers does not have a high degree of wear or abrasion characteristics. This limits the dampers use to W 097/38237 PCTrUS97/05827 applications where the damper is not ~".pGsed to abrasive or wear type envi.o.. - -.ls. Wear or abrasion could be induced by repeated contact ofthe damper to other objects or exposure to a flow of material (fluids such as air, water, etc.).

The ~~-ecl-~nicm by which current dampers ~ic~ A~le undesirable energy by d~mring resonant vibrations, involves de~.l..aliol~ or sl~ail~ing ofthe ~
material. That is, when the structure that the damper is applied to is subjected to cyclic loading, for example, the d~nrin~ material is subjected to tension-co~ ession de~.l.~ion and diecipates the energy through an extensional strain mecl~ni~.., In addition, damping can occur by energy ~icsiration from the da-~ gmaterial via a shear .~Çl~ 5.~ that results from consll~.nl created by the damper being placed between two structures (for example, an actuqtor motor and cover orbase). The dampers can also act as isolators by reducing the vibration l~ c~n;~
from a vibration or shock source to the structure on which the dampers are beingused. The peak shock and /or vibration energy or peak acceleration is reduced byuse of the damper.

Although the current dampers used in drives are reasonably effective, the problems in using the dampers with a tacky damping material can be difficult and as the drive requirements for ~leAnl;neSC, out~ccingJ ease of application, etc. become more restrictive these probl_llls could limit the use of the d~pe~ s. Thus, an alternative approach is needed to damp vibrational or shock energy without negative effects of the current dampers.
Summary of the Invention The present invention provides a novel attçnll~ting article that can overcome the negative aspects of the current d~l.l)cl ~, and even offer the potential forimproved ~mping and isolation perforrnance.

~ , .

W 097/38237 rCTAJS97105827 - The novel article ofthe invention conl~JIi3e,s (a) a vibration ~ttçn~ting material, wherein the vibration ~ltten~ ting material has a storage modulus greater than about 6.9x103 Pascals and a loss factor greater than about 0.01 at 25~C and 1 Hertz, wherein the vibration ilttemJ~ting material has a surface and an interior;
(b) an exterior film covering, wherein the exterior film covering film has a tensile modulus greater than about 6.9x103 Pascals at 25~C and 50% relative humidity, wherein the exterior film covering co~ ises one or more of the following:
(i) a film;
(ii) a film segm~nt;
wherein the vibration ~tten.l~tinE material surface is at least partially enclosed by the exterior film covering;
whel ein an inner surface of the exterior film covering col~",ls to the surface of the vibration ~ttPn~)~ting material that it is at least partially enclosing;
wherein at least a portion of the surface of the enrlosed vibration ~ttenu~ting material has a three dimensional shape;
(c) optionally one or more interior film dividers, wherein each interior film divider has a tensile modulus greater than about 6.9x103 Pascals at 25~C and 50%relative hurnidity, wherein each interior film divider co"l~,lises one or more of the following:
(i) a film;
(ii) a film seg~..P~
wherein each interior film divider separates at least a portion of the vibrationatten-l~ting material from another portion ofthe vibration ~tt~n-~ting material; and (d) optionally a layer of adhesive coated on one or more of the following:
(i) at least a portion of a surface of the exterior film covering;
(ii) at least a portion of a surface of any interior film divider, if present;
(iii) at least a portion of any vibration att~n~1~ting material which is not enclosed by the exterior film covering.

W O 97/38237 PCT~US97/05827 - wherein when the vibration ~ttçn~tin~ material is completely enclosed by the exterior film covering a layer of adhesive is coated on at least a portion of an outer surface of the exterior film covering.

S The exterior film covering is des~;.ibed herein as having two surfaces, an inner surface which is in contact with the vibration atten~ting surface and an outer surface which is its surface which is not in contact with the vibration ~ttçn~ting material.
An embodiment ofthe article ofthe invention is that wherein at least one interior film divider has multiple layers, wherein at least two of the layers have di~~ g chemical compositions.
The present invention also provides a method of ~ttçnu~ting vibration in a structure comprising the step of po~itioning an flttçn..~ti~ article in relation to the structure such that the attçnu~tin~. article is capable of ~tt~nu~ting the vibration of the structure in at least one vibrational mode, wherein the ~ttenu?ting article comprises:
(a) a vibration ~tten-l~ting material, wherein the vibration att~n~ting material has a storage modulus greater than about 6.9x103 Pascals and a loss factor greater than about 0.01 at 25~C and I Hertz, wherein the vibration atten-J?tin~
material has a surface and an interior;
(b) an exterior film covering, wL.ein the exterior film covering film has a tensile modulus greater than about 6.9x103 Pascals at 25~C and 50% relative humidity, wherein the exterior film covering comprises one or more of the following:
(i) a film;
(ii) a film segm.o.nt;
wherein the vibration atten~tin~ material surface is at least partially enclosed by the exterior film covering;
wherein an inner surface of the exterior film covering con~o""s to the surface of the vibration ~tteml~ting material that it is at least partially enclosing;

.. . . , . ~ . . . .. .. .. ~ .

- wherein at least a portion of the surface of the enclosed vibration ~tt~nl~tin~
material has a three dimensional shape;
(c) optionally one or more interior film dividers, wherein each interior film divider has a tensile modulus greater than about 6.9x103 Pascals at 25~C and 50%relative humidity, wherein each interior film divider ~~ Jl ises one or more of the following:
(i) a film;
(ii) a film segm.~nt;
wLcrein each interior film divider 5ep~aleS at least a portion of the vibration damping material from another portion of the vibration damping material; and (d) optionally a layer of adhesive coated on one or more of the following:
(i) at least a portion of a surface of the exterior film covering;
(ii) at least a portion of a surface of any interior film divider, if 1 5 presen~, (iii) at least a portion of any vibration ~tten-~qting material which is not enclosed by the exterior film covering.

A p~relled method is that wherein the vibration amplitude ofthe structure has been reduced by at least about 10% in one mode.
The exterior film covering is described herein as having two surfaces, the inner surface which is in contact with the vibration att~nu~ting surface and the outer surface, which is its surface which is not in contact with the vibration ~ttçml~ting material.
Preferably the structure in the above listed method is selected from the group consisting of disk drive assemblies, optical disk drives, compact disk assemblies, appliances, ~ sl)ol L vehicles, automobiles, doors, drawers, hoods, computers, test equipment which is sensitive to shock or vibrations, and the like.
As a specific example, an article of the invention, when used to damp a disk drive, may be placed between the top magnet plate of the actuator voice coil motor assembly and the disk drive top cover. The vibration ~ttçml~tor is typically placed - under 140 percent co~ ress,on when the cover is ~tt~rhed to the base of the drive.
The damper could also be placed, for example, between the bottom magnet plate and the base of the disk drive. This damper location may not have ~ignifir~nt co""),~ssion, but the damper does contact the base of the drive and the bottom -S magnet plate. U.S. Patent No. 5,224,000, provides additional detail regalding disk drives.
Another embodiment of the method of the invention is that wherein the structure is a disk drive assembly, wherein the article is positioned between anactu~tor and a surface opposite the actl~tor such that the article can be contacted by the actuator during actuation.
As another example, an article of the invention when used to isolate a disk drive a~tu~tor may be placed between an edge surface ofthe voice coil motor, typically on the coil of the voice coil motor or the side edge of the "E-block"
asscl"bly used to support the read/write çlemçnts~ or on a surface opposite the coil or " E-Block" assembly, when the voice coil motor is actu~ted or is subjected toexcessive vibrations or shocks allowing the actuator to i.~ ge against a surfacewith the article, the article of the invention ~ttenu~tçs the vibration or shock.
As another example, an article of the invention can be used to isolate a door or drawer when the structure is opened or closed, (i.e. actu~ted in the door or drawer frame thus producing a vibration or shock). The article may be placed on the door or drawer at a location that will contact the structure the door or drawer is being impinged against. The article of the invention will attçm.Ate the vibration or shock energy and reduce the acoustical noise and vibration level.
The present invention also provides a structure having an Att~nuating article positioned in relation to the structure such that the atten.~ting article is capable of attenll~ting the vibration of the structure in at least one vibrational mode, wht;~t;in the article comprises:
(a) a vibration attçn~l~ting material, wherein the vibration ~ttçn~l~ting material has a storage modulus greater than about 6.9xl o3 Pascals and a loss factor greater than about 0.01 at 25~C and I Hertz, wherein the vibration attçn-lAting material has a surface and an interior;

.. ~ .. .... . .

(b) an exterior film covering, wherein the exterior film covering film has a tensile modulus greater than about 6 9x~03 Pascals at 25~C and 50% relative humidity, wherein the exterior film covering comprises one or more of the following (i) a film;
(ii) a film seen.ç~ l, erein the vibration ~tt~nU~ting material surface is at least partially enclosed by the exterior film covering;
wherein an inner surface ofthe exterior film covering sllbst~nti~lly col~lms to the surface of the vibration attçno~tine material that it is at least partially enclosing;
wherein at least a portion of the surface of the enclosed vibration ~ttçn~l~tinematerial has a three di...c;l.s;onal shape;
(c) optionally one or more interior film dividers, ~hel ein each interior film divider has a tensile modulus greaterthan about 6 9x103 Pascals at 25~C and 50%
relative humidity, wherein each interior film divider colllplises one or more of the following (i) a film;
(ii) a film seg~
wherein each interior film divider separates at least a portion of the vibrationd&,..ping material from another portion of the vibration damping material;

(d) optionally a layer of adhesive coated on one or more of the following:
(i) at least a portion of a surface of the exterior film covering;
(ii) at least a portion of a surface of any interior film divider, if prese..l, (iii) at least a portion of any vibration ~ttçnu~tine material which is not enclosed by the exterior film covering W 097138237 PCT~US97/05827 - Definitions The term "atten~tQr" as used herein inchldes dampers, isolators, and co...l~;l.dlions thereof that dicsipate vibration energy and/or shock and/or change the S vibration and/or shock ll~ns~ ed to a structure that it is used with, in or on.

The terrn ''atten~1atine material" as used herein refers to a material that provides vibration and/or shock energy dissipation and/or shock and/or vibrationisolation improvement.
The novel articles of the present invention overcome the many shortfalls of current damper designs by having the following design and application advantages:

1) An optimum vibration ~tten~l~tine material can be used for a given application, without the Tg, and thus the potential tac~in~ss of the material nfceSs~ ily being a limiting factor to the design or use of the novel article. The novel article design provides for partial or complete enclosure of the attç~ ting material to limit negative effects of using a plere-led vibration ~ttçm.~tine material.

2) The novel articles can be desiened such that they ~,vill not experience negative "blooming" effects as some current da~ e. s do. The exterior film covering may cover the vibration atten~ating material completely or to a large extent andprevent the vibration ~ttçn.l~tine material from blossoming around the exterior film covering and creating contact with an undesired surface.
3) The novel articles of the invention do not require a film e~t~qn~1ing away from the attPn..~fine material surface to prevent blooming around the film edges as some existing dampers use. The current dampers that use a film extçn-ling away from the damping material surface are expensive to m~nllfac.t~lre, difficult to handle, and complex to m~nllf~ctllre.

W 097/38237 PCTrUS97/05827 - 4) The novel articles of the invention are a unitary design. Single piece construction reduces application costs as con~pared to the current two-part damper used in many disk drives.

5) The novel article of the invention allows tacky vibration ~ttçn~ting materials having low Tgs and/or low crocclinking levels to be used. The novel article can çlimin~te the proble~ associated with using the optimum tacky vibration s~ttçnll~tin~ materials for a damper. Previously, some dampers have overcome some of the current damping material problems (for eY~n ple the tacky characteristic of the darnping material at application or drive opel dlhlg temperature), but in doing so they created new problems by using high modulus (high Tg, high cross-linking) d~..ping materials which have minim~l stress relaxation and thus retain a significant amount of stress when cor..l~essed. As many appli~tion~ require stress relaxation, for example, to prevent the disk drive cover from being bowed during or after the dampers application, the high Tg damper is not acceptable for many applications.Plus, the damping pe,r~",lal1ce ofthe damper is less than Oplilllulll.

6) The novel articles of the invention can potentially use an optimum vibration ~ttçnll~ting material which may be, for example, a tacky material and .. ~ ;.. i7f': collection of co,.l~n~ ion, as a ci~nifi~ n~ portion ofthe surface ofthe article may not be tacky dependillg on the size of the exterior film covering. In addition, the novel article may, depel1dillg on its design, be effectively cleaned by hand or in automatic cle~ning systems. The current gene,~ion vibration ~tt~n--~ting materials are not easily cleaned and collect co..l;....il-~l;on (dust, debris, etc.) easily as a tacky surface is often related to the da.l.pin~, material. As a damper may need to be clean to a level s~-ffisient to meet a clean room deci~n~inn of Class 1 or Class l O0, the novel article of the invention is particularly advantageous.

7) The novel articles of the present invention can use films that act as barriers to components out~c~in~ from the vibration ~ttçn~l~tin~ material (examples include unreacted monomers, impurities, small molecular weight reaction W 097/38237 PCTrUS97/05827 - components such as alcohols, catalysts such as those based on tin or pl~timlm, etc.).
The o~lt~csing components may have a reduced surface area from which to escape as col.lpared to conventional da.llpel~ wherein the vibration ~tt~n~ting material is not enclosed as in the article of the present invention. The exposed areas of the S vibration ~qttPn-~ting material can also be signifir~ ltly less than for the vibration ~ttP.n-~?tin~ material of a current damper.

If pre-outg~sci~ should be needed for the novel articles of the invention this also can be accomplished, but with the added benefit that the vibration ~ttçn.~ting material is generally not exposed and thus will not collect debris if o~tg~c~ed on a convection type air heated oven. The novel article design is also less likely to absorb undesirable components that the articles may be exposed to during cle~ning, sllil)pillg, h~nflling and m~nufactl1re and that could outgas at a later time.

8) The article of the invention is easily positiQnp~d by hand or by the use of a~P~~ device such as tweezers, graspers, etc., with little or no limit~tion basedon the type of vibration ~tten~ting material used in the article. ~ltorn~ted devices may also be used to position the article of the invention. Current dampers can be difficult to handle and efforts to automate their p!rc~PnnPnt would require special methods to handle a tacky attçn~l~tin~ material.

9) The novel articles of the invention can have a plethora of shapes and provide greater ranges for dimçmion~ and aspect ratios than known dampers. The novel articles may optionatly have one or more of the fotlowing features: holes,25 multiple contours, ridges, raised portions, flat surfaces, protrusions, convex features, concave features, and flaps of film at the article's edges. These features allow the article to be custom shaped for specific applications and can atlow the article to have less conventional shapes to aid in locating the part for assembly or inspection.

W 097/38237 PCT~US97tO5827 - 10) The articles of the invention can have up to 100% of the vibration ~ttçnll-tin~ material surface covered by the exterior film covering, thus improving the oxidative rçcict~nce ofthe vibration ~ttçnu~ting material at elevated tclllpclalLlre for short times or at mPAillm tclllpel~llJres at long time. The vibration attçn~atin~
5 mater.ial may be sub~l~llially or completely protected from oxidative deterioration (depending on the size and characteristics of the exterior film covering, etc.), and thus is more likely to retain its vibration ~ttçn~ tin pr~pel Lies.
Oxidation is d~tl il..clltal in that it can change the prop~ ies of the vibration ~ttçnu~ting material of the article and decrease its benefits. The use of the exterior 10 film covering can also allow the use of a vibration att~nu?tine material which is substantially free of oxidation inhibitors (antioxidants, for example). The ç~ ion or reduction of antioxidants and other rhçmic~ to çl~h--nce the thermal oxidative stability of the vibration attçnu~tin~ material used in the novel article of theinvention can allow for the use of a less costly danl~ g material, a material which experiences less oul~,~c~ as well as a material which has a higher polymerization degree and which can be p. cpal ed via a faster reaction conl~al ed to those materials which contain oxidation inhibitors.
Further, the novel articles of the invention may utilize films of multiple layers. The multiple layers can improve the barrier p~o~>el ~ies of the film(s) layer.
They can also provide good conrolll,ability to the vibration ~tt~mlS~ting material and also reduce the stiffnçs~ of single layer film. For eAa,lll~le, a film 6 mils (0.1 5mm) thick may be stiffer than a tri-layer film of three layers each 2 mils (0.051 mm) thick, each layer separ~ted by an adhesive layer or otherwise bonded to each other with a lower modulus material. Multiple layers bonded together via a vibration ~ttçm-~tin~ material may also improve the vibration attçnl~ ting ability of the article as col,.pared to a single film layer.
The use of an exterior film covering which may cover a large portion or all of the vibration att~nuatin~ material may also lead to inc~ eased shearing of the vibration atteml~ting material in shearing and co"-p-t~sion-tension modes. Thus improved damping may be achieved by the use ofthe novel article over the conventional damper.

W 097/38237 PCTrUS97/05827 - Protrusions ~oYt~.nrlinp from the exterior film covering into the vibration attçnu~tin,~ material can also improve the shearing effect in the vibration ~ttenu~ting material and further increase vibration ~ttenwtisn A portion of the resulting meçh~nical strain energy in the vibration attçn-~ting material is then ~lissipqted in the form of heat. The higher the strain energy into the vibration ~tt~nu~ting material, the more vibration energy is ~icQip~ted from the system in which the article is used.

1 l) The novel article ofthe invention may have increased enviro~
l 0 survivability with the use of various wear/abrasion, çh~mi~lly, thermally and radiation (for e.~nple, ultraviolet or infrared radiation) resistant films and/or film se~..e~llc. The novel articles ofthe invention may have improved resict~nce to harsh envirnn~ c such as gases or solutions they may come into contact with during m~nllf~cture or use. These harsh m~il mc can react with exposed vibration~ttçmls~ting material to reduce the benefit ofthe article. In addition, reactions bel~een the vibration ~ttenU~ting material and the harsh envil onl"~lll can create secondary co,.")onenls that may have a negative e~ect on other materials near the article's use location.
Furthermore, components or agents used in the vibration ~ttçn~ ting material m~mlf~ctllre may escape from the artide and have negative effects on materials near the article's use location. For example, if the vibration ~ttçml~ting material uses a catalyst that can be leached from the vibration ~ttçm~tin~ material, it can cause d~L,hl,~"Lal reactions to occur elsewhere in the area near the article's use location.
12) The novel article of the invention can be desig1led to have a high degree of wear or abrasion recist~nce. This improved wear and abrasion re~ict~nce expands the article's use to applicaLions where the current generation dampers are not utilized because of conc~ s l egardh~g abrasion or wear. Wear or abrasion could be in~uced by contact of the article to other objects or exposure to a flow of material (fluids such as air, water, slurries, etc.).

W O 97/38237 PCTrUS97/05827 Brief De~ tion of the Drawin~s Fig. I illustrates a partially exploded view of a disk drive showing a location where a damper could be used.
Figs. 2-2d illustrate cross-sectional views of prior art d~.l~)e~ ~.
Figs. 3a-31 illustrate top plan views of embodiments of the articles of the invention.
Figs. 4a-4m illustrate cross-sectional view of emborlim~nts of the articles of the invention.
Figs. 5a-5h illustrate cross-sectional view of embo.iim~onts ofthe articles of the invention.
Figs. 6a-6c illustrate cross-sectional view of embodim~nts of the articles of the invention.
Figs. 7a-7c illustrate cross-sectional view of emb~diments of the articles of the invention.
Figs. 8a-8d illustrate cross-sectional view of embodimçnt~ of the articles of the invention.
Figs. 9a-9d illustrate cross-sectional view of embodiments of the articles of the invention.
Figs. 1 Oa- 1 Oc illustrate cross-sectional view of embodiment~ of the articles of the invention.
Figs. 11 illustrates a cross-sectional view of an embodiment of the article of the invention.

Detailed Dcrc. ;~tion of the Invention ARTICLE S~APES
The article of the invention, as well as the vibration ~ttçnu~tin~ material, may have a variety of shapes. The shapes may or may not be symmetrical.
Ex~ples of suitable shapes include but are not limited to those selected from the group consisting of polyhedrons such as cubes, rings, pyramids, prisms, trunc~ted - pyramids, stepped pyramids, stepped le~ gles~ etc., and other shapes such as cylinders, cones, spheres, hçmi~pheres, pillows, etc.
The article may optionally have at least one flat surface which may be used to mount the article for its intended applicalion. This surface typically has anadhesive (most typically a pressure sensitive adhesive) coated thereon to aid inmounting the article. The adhesive may be coated onto any exposed vibration ~tteml~tin~ material and/or the outside surface of the exterior film covering that encloses the vibration ~tten-~ting material. The exposed vibration ~ttenl~tin~
material may possess adhesive cha, _~ :eristics itself and thus could aid in adhering the article to a surface if desired.

EXTERIOR FILM COVERINGS AND INTERIOR FILM DIVIDERS
The exterior film covering co,.,p~ ises one or more films and/or film se~ s of various p- UpCI Lies. Likewise, the interior film dividers may comprise one or more films and/or film seg.n~ of various prope~ ~ies. These films and/or film se~ n~ may have the same or d;rre~e.l~ che".c~l compositions, ~ n~ n~
(thickness, widths, lengths) etc. These films and/or film se.e~ may adjoin, overlay, overlap each other, etc. These film(s) and/or film se ,,.~nl(s) may be contim~o~ls or discontinuous, with or without perforations, holes, and/or slits, etc.
Likewise the exterior film covering and the interior film dividers may be continor discol,~ ous, with or without pe~rulalions~ holes, and/or slits, etc. The exterior film covering and the interior film dividers, as well as each film and/or film se~n~nt which make them up, may optionally have various degrees of surface roughn~c in order to modify the article's pe~rc"".dl~ce.
Various films and/or film seg,.~ may be used in the exterior film coverings and internal film dividers. The films and/or film seg...-...ls may be woven and/or non-woven. For example, the non-woven could be a hot melt blown micro-fiber of polypropylene and/or polyester. The films and/or film seg. . .~nl ~ mayoptionally be porous. Polymeric and/or non-polyrneric films and/or film seg. .~nl S
may be used. E~l,ples of suitable polymeric films include but are not limited tothose selected from the group consisting of polyester, polyimide, polyamide, .

W 097/38237 PCT~US97/05827 - polyethylene, polypropylene, acrylic, phenolic, polyvinyl chloride, polyurethane, polystyrene, fluorinated polymer films (such as those available under the trademark Teflon from DuPont), polyvinyl acetAtes, nylon, etc. Useful non-polymeric films and/or film seg~ include but are not limited to those selected from the group cons;sling of ~ min~m gold, silver, ~IA;~IeSS steel, copper, brass, etc. Amorphous polyester is a ylerelred film.
The films and/or film se~ c may optionally be metAli7e-1, corona treated, pi~m~nte~l, provided with a release surface, provided with a surface capable of ~i~cip~ting static electricity, provided with a reflective surface, provided with an adhesive surface, provided with environm~nt~l re~:~lA.-ce (i.e. re~;C~A.-ce to heat, hurnidity, chemicals, radiation, and/or vacuum effects, etc.), provided with wear or abrasion res~ nce, provided with co...; ~ ity (envirol.n~e~ lly, ...ecl1Ai-:c.~lly, and/or chemicAlly) with a plal~ed surface that it will cont~ct, provided with a low energy surfaces, provided with ~ceol~s and/or liquid barrier properties, and/or provided with thermal and/or electrical con~ c.tivity in order to provide an exterior film covering and/or internal film divider having such prope. Iies. The films and film segJnentc may be coated with various c~tingS such as epoxies, waxes, silicones, fluoropolymers to impart release characteristics or low energy surfaces to the exterior film covering and/or the interior film divider. The films and/or film se,~,,.. ~l-l s may optionally be hl~yr~ Aled with various materials to modify their propel ~ies (such as fillers, tough~ning agents, colorants, fibers, partiC~ te~ etc.) The film and/or film se~m~nt p-ope- Iies may be localized to specific areas if desired.
Different films andlor film seg~ 1 s may be used to provide an exterior film covering or an internal film divider with di~l elll pl opel Iies. For example, the exterior film covering may comprise two layers which can be identified as an inner film and an outer film. An inner film may be selected to which the vibration ~tten-~Atin~ material readily adheres while the outer film of the exterior film covering may be selected which provides better exterior wear characteristics to the damper (such as scuff resislance). Other exterior film coverings are possible. The exterior film covering may co,,,yl;se one, two, three, four, five, or more layers of film and/or film se~n~ Likewise each interior film may comprise one, two, three, W O 97/38237 PCTrUS97/05827 -four, five, or more layers of film and/or film seg,..~ . As another eA~Ilp1~ the exterior film covering may have inner and outer layers which are the same, but amiddle layer which is dil~ wll. If the exterior film covering co",p, ises more than one film or film se~ l the films and film se~nPnts may optionally be bonded togeth~r via an adhesive such as a pressure sensitive adhesive or otherwise optionally bonded together by other means. The same potential for bonding also applies to the interior film dividers.
Other ~ ..ples include a three layer exterior film covering construction comprising a low density/high densityllow density polyethylene construction, a low density /me~ m density Aligh density polyethylene construction, and a low density polyethylene/high density polyethylene/low density polyethylene. One or more of the afol e~ nlioned film layers may cptionqlly be thermally or electrically conductive. The exterior film covering may also co",p,;se, for example, constructions of polyester/polyimide or acrylic/polyester or polyethylene/polyamide, 1 5 etc.
The article of the invention may optionally have one or more i~pl ei,;,;ons therein in order to aid application, assembly or ide-ntific~qtiQn of the articles for m~mlfqctllrer, end-user, application, etc. The h~ples~ions can be made in one ormore ofthe following: the eAterior film covering, the vibration qtt.on--qting material, the interior film divider(s). An eAa"")le would be an idçntific.~q-tion logo to identify the end user.
As mentiorled previously the vibration attenl~-qting material may be partially or completely enclosed by the exterior film covering. When the vibration ~qtten~l~ting material is partially enclosed by the exterior film covering typically about 50 to about 99 percent of the surface of the vibration ~tteml~ting material is enclosed by the exterior film covering, more typically about 60 to about 90 percent, and most typically about 65 to about 85 percent.
The exterior film covering may optionally have features such as protrusions, hll~ ,ss;ons, etc. These features may be on the side of the exterior film covering contacting the vibration attçn--~tin~ material or on the side of the exterior film covering not cont~cting the vibration ~tten~tin~ material, or both. These fealules ... . .. .

- may impart various potential pel rO, ~llance characteristics to the article or aid in its intentled end use. The protrusions can also improve the bonding or adherence of the film to the ~ttenu~ting material. Likewise the interior film dividers may have such features on either or both sides thereof.
The exterior film covering encloses the vibration ~tt~n.l~tin~ material. A
surface of the exterior film covering that contacts the vibration attçn-l~ting material is considered to be an inner surface, whereas a surface of the exterior film covering which does not contact the vibration ~ttenlJ~ting material is corlQidçred to be an outer surface. Some designs allow for one film to fi~nctiQn as an exterior film covering for a sections(s) ofthe article where it encloses vibration ~ttenl~tin~material by only one of its sides but as an interior film divider where it is contacted on both of its sides by vibration ~ttçn-~tin~ material. This concel)l is furtherexpl~ined in the discussion of the Figures.
Optionally two or more of the articles of the invention can be joined together by or through their exterior film coverings. (for example one continuous film may serve as part of the exterior film covering of two or more articles).
Optionally two or more of the articles of the invention may be adhered together either via an adhesive or via exposed vibration i~ttçnn~ting material.
The adhesive layer can co,,ll,l ise one or more layers of adhesive which may be the same or di~ere,lL. The adhesive layer may for eA~ !e, be fully cured or partially cured. Exallll)les of suitable adhesives include but are not limited to those selected from the group consisting of pressure sensitive adhesives, epoxies, structural epoxies, and the like. The adhesive layer may be contimlo~-s or discontinuous.
VIBRATION ATTENUATrNG MATERIALS
The term "vibration ~tt~nu~tin~ material" as used herein incl~ldes vibration damping materials, vibration i~o!~tin~ materials, colllbh,alions thereof, etc.
The vibration and/or shock Atten-l~tinp~ material can include any material that is viscoelastic. A viscoelastic material is one that is viscous, and therefore capable of dissipating energy, yet exhibits certain elastic propel lies, and thererore capable of storing energy. That is, a viscoelastic material is an elastomeric material typically cGn~ inp long-chain molecules that can convert n~ecl~ ical energy into heat whenthey are deformed. The viscoelastic material can also be designed to have the desired elastic characteristics needed to provide isolation propcl lies and a lower level of dan~pin~ than as used in a design where damping is a primary design S objective. Such a material typically can be de~l,lled, e.g., stretched, by an applied load and gradually regain its original shape, e.g., contract, so~net;...e after the losd has been removed.
Additives such as flame retardants, anti~xid~nts, fibers, anti-static additives,particulate and colorants can also be added to the ~tten~ting material to impart specific pwro.~ ce features.
The viscoelastic ~ttçn~ting material useful in the invention can be a thermoplastic polymer or a thermoset polymer or co...bh~alion of both fully or partially cured. Thermoset polymers, while useful as viccoel~ctic ~ttçn~ting materials, are used less often than ll.e....o~l~cl;c polymers due to their lower15 e~ective te,,,pelal~lre range of high damping. Ple~lably~ the viccoelS~ctic ~ttçn~tinP material is a thermoplastic polymer, such as an acrylate.
Suitable viscoelastic materials for use in the vibration ~ttçn-~ting materials ofthe present invention have a storage mo~ us, i.e., measure ofthe energy storedduring dero,...alion, of at least about I psi (6.9 x 103 Pascals). The storage modlllllc of useful viscoelastic materials can be as high as 500,000 psi (3.45 x 109 Pascals); however, typically it is about 1-2000 psi (6.9 x 103- 1.4 x 107 Pascals).
Suitable viscoelastic materials for use in the vibration ~ttçn-l~ting materials of the present invention that have as a primary design goal damping, have a lossfactor, i.e., the ratio of energy loss to energy stored, of at least about 0.0l .
Preferably the loss factor is at least about 0.1, more preferably about 0.5-10, and most preferably about l-10, regardless ofthe frequency and temperature experienced by the material. Suitable viscoelastic material for use in vibrationattem~tion materials of the present invention that have as a primary design goalisolation, have a loss factor of less than l .0, preferably less than 0.3-0.5 and most prere,dbly less than about 0.1. An ~tten.~tor design material should be sçlectedthat allows the isolation level required to be a~' ~cd, along with the minim~m .. .. ..

ing needed to allow control of the desired resonanl frequ~Pncies ( if the material is available).
This loss factor ~ep.esenls a measure ofthe energy tliCcip~tion ofthe material and depends on the frequency and te~ re experienced by the ~ttçn~7tinp material. For example, for a lightly cros~linlçd acrylic polymer with a Tg of about 5~C, at a frequency of 1 Hz and a primary design goal of dal..ping, the loss factor at 68~F (20~C) and 1 Hz is about 1.0, while at 1 58~F (70~C) the loss factor is about 0.7. As the Tg of a material is also an in-lic~tor of the potential for the d~.,ping material to have a tacky or sticky characteristic, especi~lly if the 10 ~ttenllating material is only lightly crosslinked, the aforellJt;~ oned acrylic damping material is very tacky at 25~C.
~ ttem~ting materials that have high Tgs (Tg >60~C at a frequency of 1 Hz) are known. However, these higher Tg materials may have less capacity to add d~ ril-g to the system at the use t~lllpelalure (for t.~ lple, the typical driveopelaling te,llpel~lure range of 5~C to 65~C). Thus, ~ttPn~l~tin~ polymers with a Tg greater than 60~C may have limited benefit for most disk drive applications. Thus, the optimum ~ttPnu~tor for a drive actuator application uses an attenl)~ting material with a Tg less than about 60~C (at a typical drive op~;ldling te..,l~e~L~lre of 5 to 65~C) and most preftl~bly an ~ttem~qting material with a Tg less than about 45~C at 20 a frequency of I Hz, and most preferably an att~nu~tin~ material with a Tg less than about 38~C at a frequency of 1 Hz.. This damper will tend to be tacky and build a strong bond to most surfaces it comes into contact with (stainless steel, ~luminllm~
epoxy co~tingc, etc.) The material se~ected for use in an isolator design that has vibration or shock isolation as the pJ;I~laly design objective, will typically have less damping (lower loss factor) than material for a design where vibration dal,l~ lg is the primary design objective.. This is because an und~mped material is superior to adamped material in reducing trancmicsibility. However, reduction in lli.n~ ccibility occurs only for frequencies greater than the square root of 2 times the natural frequency ofthe isolator, v. The.e~ore, the material must have an amount of W 097/38237 PCT~US9710S827 - domping sufficient to reduce structural le30na"l amplitudes for resonances occurring below v to an acceptable level.
Preferred vicco~lqctic materials are those that remain functional over a wide range oftemperatures, e.g., -60~F (-51~C) to 600~F (315 ~C). Most prt;rel~ed S viscoelastic materials are those that cover the broadest te,.,l)cr~lure and frequency range at the desired loss factor and storage m~ us to achieve acceptable attçnu~iorl of the item that the ott~nUotQr of the invention is being used to darnp, isolate, or both and do not CAp~l iellce a significant degradation in prop~, lies due to long times at high tenlpel alures or short excursions beyond these high ten~i)G, al~re levels.
Useful viscoelastic ott~n--~ting materials can be is~l~op.c as well as anisollopic materials, particularly with respect to its elastic prope, lies. As used herein, an "anisotropic material" or "noni30l10p c material" is one in which theprope, lies are depende~.l upon the direction of ~"e&s.lre."~l. Suitable viscoelastic materials include urelhane rubbers, silicone rubbers, nitrile rubbers, butyl rubbers, acrylic rubbers, natural rubbers, styrene-but~ ne rubbers, and the like. Other useful attçn.l~ting viccoPl?ctis materials include polyesters, polyurethon~s poly _ ~çs, ethylene-vinyl acetate copolyrners, polyvinyl butyral, polyvinyl butyral-polyvinyl acetate copolymers, epoxy-acrylate int~ enellaling networks and the like.
Examples of thermoplastic materials suitable for use as the vibration ~tt~nuvoting material in ~ottenu~tors ofthe present invention include, but are not limited to, those sPlected from the group con~ g of polyacrylates, polycarbonates, polyetherimides, polyesters, polysulfones polystyrenes, acrylonitrile-but~ ne-styrene block copolymers, polypropylenes, acetal polymers,polyamides, polyvinyl chlorides, polyethylenes, polyurethon~s, and colllbillalions thereo~
Useful viscoelastic materials can also be cros~ .oble to çnhonce their ~l~en~ Such viscoelastics are cl-o-~ified as thermosetting resins. When the viscoelastic material is a therrnosetting resin, then prior to the m~nllfioct~re ofthe attçnu-o-tors of the invention the thermosetting resin is in a thermoplastic or uncured .. ....

W O 97/38237 pcTrus97lo5827 state. During the m~mlf~ct~lring process, the therrnosetting resin is cured or crosslinked typically to a solid state, although it could be a gel upon curing as long as the cured material possesses the vi.ccoÇl~etic pl ope~Iies described above.
Depen-ling upon the particular therrnosetting resin employed, the thermosettir~
resin can include a curing agent, e.g., catalyst, which when exposed to an approp,iate energy source (such as thermal energy) the curing agent initiates the polyl"e-i~ution ofthe therrnosetting resin. Particularly p~ere--ed viwelsctic att~n-~ating materials are those based on acrylates.
In general, any suitable vibration ~ttçn~atin~ material can be used. The choice of vibration ~tten--~ting material for a particular set of conditions, e.g., te~"pe~al~lre~ frequency of vibration or shock, balance of dan-ping and/or isolation is dete",uhled by a particular application. The selection of a suitable vibration ~tt~n-~atin~ material is also based on the processability of the material. It is to be understood that blends of any of the foregoing materials can also be used.
The ~tten~ting prope, lies of the vibration ~ttçnl~ti~ article may be ~l~hAnced by the inclusion of an effective amount of a fibrous or particulate material in the ~tt~n~sting material of the ~tt~n--~ting article. Herein, an "effective amount"
of a fibrous material or particulate is an arnount s ~fficiçnt to impart at least improvement in desirable characteristics to the ~tten--ation material. Generally, the fibrous or particulate material is used in an amount effective to inc,ease the strain energy ratio of a component co~ p. the same amount and type of atten--~tion material without the fibrous or particulate material. Generally, an increase in the strain energy ratio of a factor of at least about two in at least one vibrational mode is desired. Typically, the amount of the fibrous material in the viscoelastic material is within a range of about 3-60 wt%, preferably about 10-50 wt%, more ~l ~rerably about 15-45 wt%, and most prerel~bly about 30-35 wt%, based on the total weight ofthe vibration ~ttçn~ting material. Typically, the amount ofthe particulate material in the attçnl~ating material is within a range of about 0. 5-20 wt%, p,c;re.ably about 1-15 wt%, more preferably about 5 -15 wt%, and most preferablyabout 5-10 wt%, based on the total weight ofthe vibration ~tt~n.. ~tinE material.

WO 97/38237 PCT/USg7105827 - The fibrous material can be in the form of fibrous strands or in the forrn of a fiber mat or web, although fibrous strands are prert" t;d. The fibrous strands can be in the form of threads, cords, yarns, rovings, fil~ments, etc. They can be dispersed randomly or un,rollllly in a spe~ified order. Pl~felably, the fibrous strands, i.e., fibers or fine threadlike pieces, have an aspect ratio of at least about 2:1, and more preferably an aspect ratio within a range of about 2:1 to about 10:1. The aspectratio of a fiber is the ratio of the longer dimension of the fiber to the shorter ~limP.nQi~n The fibrous material can be composed of any material that in~il eases the ~ttPnll~tion capability ofthe cured ~ttPn~ting material. Examples of useful fibrous materials in applications of the present invention include metallic fibrous materials, such as ~lllrnimlm oxide, m~g~P.sil~m or steel fibers, as well as nonmet~llic fibrous materials, such as fil)elglass. Generally, hi8h Young's modulus fibrous materials, i.e., those having a modlllu$ of at least about 1,000,000 psi (6.9 x 109 Pascals), are prer~lled. Most preferably, the fibrous material is nonmet~llic. The nol~l.. el~lliG
fibrous materials can be a variety of materials, incl~ ing, but not limited to, those sPlected from the group consisting of glass, carbon, minerals, synthetic or natural heat res;sLal,l organic materials, and ceramic materials. Plefelled fibrous materials are organic materials, glass, and ceramic fibrous material.
By "heat resistant" organic fibrous material, it is meant that useable organic materials should be s~ffi~i~ntly res;~l~,l to meltin~, or otherwise softening orbreaking down, under the conditions of m~nllf~chlre and use of the ~ttçn--?tors of the present invention. Useful natural organic fibrous materials include, but are not limited to, those selected from the group consisting of wool, silk, cotton, and cellulose. Examples of useful synthetic organic fibrous materials in~llldP" but are not limited to, those sPIected from the group CQ~ ;ng of polyvinyl alcohol, nylon, polypropylene, polyester, rayon, polyamide, acrylic, polyolefin, aramid, and phenol.
The prefe., ed organic fibrous material for applications of the present invention is aramid fibrous material. Such a material is co",l"t;l.,ially available from DuPont Co., Wilmin~on, Delaware under the trade names of "Kevlar" and "Nomex."

CA 02248828 l998-09-09 Generally, any c~ Lc fibrous material is useful in applications of the present invention. An tA~Illple of a ceramic fibrous material suitable for the present invention is NEXTELTM which is co,.. ç~c;ally available from Minnesota Mining and l~nl~f~ct~ring Co., St. Paul, Mh~llesola. E~n~les of useful, co.ll,..e.cially 5 available, glass fibrous material are those available from PPG Industries, Inc.
Pittsburgh, Pennsylvania, under the product name E-glass bobbin yarn; Owens Corning, Toledo, Ohio, under the product name "Fiberglass" continuous fil~rnçnt yarn; and Manville Corporation, Toledo, Ohio, under the product name "Star Rov 502" fiberglass roving.
Advantages can be obtained through use of fibrous materials of a length as short as about 100 micrometers. The fibers are not limited in length but much longer fibers may provide insufficient fiber interface and therefore decl eas~d shearing surfaces between fibers. The fiber thickness or rli~meter for typical fibrous material ranges from about at least S micrometers. The thinner the fiber, the higher the surface area of the fibrous material. Thus, preftl I ed fibrous materials are very thin. The thickness of the fiber is also dependent upon the desired thickness of the overall damper of the invention. Thus, many co,llmoll fibers may be suitable.
The particulate material useful in the invention can be in the form of glass and ceramic bubbles or beads, flakes, or powder, as long as the viscoelastic can wet the surface of the material. The particulate material can vary in size and be a random distribution or a specific distribution of size(s) within the practical limits of the att~ml~tor design. Pl~fel~bly, the particulate material is on the size order of about 0.1 to about 5 micrometers and more prefel ~bly about 0.1 to about 2 micrometers. The particulate material can be composed of any material that increases the atten~l~sin~ c~pability of the ~ttenl~ting material.
Examples of useful particulate materials in applications of the present invention include coated or uncoated glass and ceramic bubbles or beads such as thermally conductive bubbles, electrically conductive bubbles, powders such as ~lllmimlm oxide powder and ~hlminllm nitride powder, silica, cured epoxy nodules, uncured epoxy nodules, and the like, i.e., those having a modulus of at least about 10,000 pSi(6.9 X 107 Pascals), are prer~l~ed. More preferably, usefi~l particulate , ~, W 097/38237 PCT~US97/05827 ~ materials have a Young's modulus of about 100,000 psi (6.9 x 108 Pascals), and most pr~fe,able are those with a modulus of at least 1,000,000 psi (6.9 x 109 Pascals).
In addition to fibers and particulate material, the vibration attçn-l~ting material of the present invention can optionally include additives such as fillers (e.g.
talc, clay, etc.), colorants, to~lghenin~ agents, fire retardants, ~nti~t~tic agents, ~ntioxid~nt~, and the like. S~lffi~içnt amounts of each of these materials can be used to effect the desired result.
This invention will be better understood by referring to the following figures which are not meant to be limiting Figs. 3a-31 illustrate various top plan views of the article of the invention.
Figs. 3a-31 shows dampers having rect~n~ r, key-hole, non-angular symmetric, tri~n~ r, square, star, T-shaped, circular with a central hole, symmetrical angular, ClGSCGIIt, irregular, and ~,rescenl with one circular and two rect~n~ cut out shapes, r~s~)e.,~ ely. In Figs. 3a-31 the exterior film coverings are represented as 36 to 47, les~,e.,li~ely. In Fig. 3h the circular hole is rep~esel.led as 48. In Fig. 31 the circular hole cut out is leplese~led as 50 and the re~ g~ r cut outs are epres~ ed as 52.
Fig. 4a illustrates a cross-sectional view of an article of the invention comprising exterior film covering 54 and vibration attçn~l~tin~ material 58, thearticle having a central raised portion with a flat surface 59 and an adhesive layer 56.
Fig. 4b illustrates a cross-sectional view of the article of the invention comprising exterior film covering 60, vibration attçn~ting material 62, and pressure sensitive adhesive layer 64.
Fig. 4c illustrates a cross-sectional view of an article of the invention comprising exterior film covering 66 and vibration ~ttçnll~ting material 70, thearticle having a central raised portion with a flat surface 69, and a pressure sensitive adhesive layer 68.

wo 97/38237 PCT/US97/05827 Fig. 4d illustrates a cross-sectional view of the article of the invention colnplisillg exterior film covering 72 vibration ~tten~.~tin~ material 74 and pressure sensitive adhesive layer 76.
Fig. 4e illustrates a cross-sectior~' view of the article of the invention co~npli~;"g exterior film covering 78, vibration ztt~n.J~tine material 80 and pressure sensitive adhesive layer 82.
Fig. 4f illustrates a cross-sectional view of the article of the invention comprising exterior film covering 84, vibration attt n~l~ting material 86 and pressure sensitive adhesive layer 89.
Fig. 4g illustrates a cross-sectional view of the article of the invention co",p,;sing exterior film covering 90 and vibration attçn..~ting material 92 thearticle having a raised curved portion 91 and a raised flat portion 93.
Fig. 4h illustrates a cross-sectional view of an article of the invention comprising exterior film covering 94 and vibration Attenu~tin~ material 96.
Fig. 4i illustrates a cross-section~l view of an article comprising two articlesof the invention joined together by their exterior film coverings 104 and 100. One article cor,Lains vibration Attçn.nAtin~ material 106 and the other contains vibration att~n-l~tin~ material 102. Adhesive layers 103 and 105 is present on the exterior film covering 104.
Fig. 4j illustrates a cross-sectional view of an article of the invention comprising exterior film covering 110 (~"~"is;ng film se~mçnts 113 and 115, vibration ~ttçnu~ting material 112 and pressure sensitive adhesive layer 114 wherein the article has a tri~n~-lAr cross-section.
Fig. 4k illustrates a cross-sectiQn~l view of the article of the invention co,np,isillg exterior film covering 116 and vibration Atten~tin~ material 118, wherein the article has a prism shape. The exterior film covering 1 16 extends away from the vibration ~ttem~tin~ material 118 to form flaps 120.
Fig. 41 illustrates a cross-sectional view of the article of the invention comprising exterior film covering 122 (comprising film se~;~"~nls 123 and 125) and vibration attenu~ting material 124, having two projections (126 and 128) e~cten~ing from the top surface of the article at either side of the top surface.

W097/38237 PCT~US97/05827 Fig. 4m illustrates a cross-sectional view of an article of the invention CGIl.pli~;ng exterior film covering 130 (comprising film segrnçnts 133 and 135),vibration attçn~ting material 132., having a central projection 136 extPn-iing from the top surface of the article.
Fig. Sa illustrates a cross-sectional view of an article of the invention - comprising exterior film covering 138, vibration ~ttçn~ating material 140, and pressure sensitive adhesive layer 142 coated against the exposed surface of vibration atten~tine material 140.
Fig. 5b illustrates a cross-sectional view of the article of the invention comprising exterior film covering 144, vibration ~ttP.n-~ting material 146, and pressure sensitive adhesive layer 148. The exterior film covering 144 and pressure sensitive adhesive layer 148 extend to form flaps 150.
Fig. Sc illustrates a cross-sectional view of an article of the invention col..l,.;sing exterior film covering 152, vibration ~ttçn~ating material 154, and 15 pressure sensitive adhesive layer 156.
Fig. 5d illustrates a cross-sectional view of the article of the invention co..-p.ising exterior film covering 158, vibration ~ttçn~ting material 160, pres~ur~
sensitive adhesive layer 162, film layer 164, and pressure sensitive adhesive layer 166.
Fig. Se illustrates a cross-sectional view of an article of the invention comprising exterior film covering 168, vibration ~ttçn-~ting material 170, interior film divider 172, a di~ren~ vibration ~tten~l~ting material 174, pressure sensitive adhesive layer 176, and flaps 178.
Fig. 5f illustrates a cross-sectional view of the article of the invention comprising two separate attenn~tors adhered together, the first comprising exterior film covering 180, vibration ~ttçnl~tinp~ material 182, and pressure sensitive adhesive layer 184, and the second comprising vibration ~ttçn~-~ting material 188, exterior film covering 186, and pressure sensitive adhesive layer 200.
Fig. 5g illustrates a cross-sectional view of the article of the invention comprising exterior film covering 202, vibration ~tt~n~ting material 204, interior . .

film divider 206, a di~rerent vibration ~ttçm.~tine material 208, pressure sensitive adhesive layer 210, and flaps 212.
Fig. Sh illustrates a cross-sectiQn~l view of the article of the invention co~ ising exterior film covering 214 (made up of film se~ s 216, 217, and 219), vibration attem~qting material 218, pressure sensitive adhesive layer 224, and flaps 220.
Another embodiment of the article of the invention comprises an exterior film covering with holes, vibration ~ttçnu~ting material, pressure sensitive adhesive layer, and flaps.
Another embodiment of tthe article of the invention comprises an exterior film covering which col"l ,;ses film and film se~ 1 vibration ~ttçml~tinp material, pressure sensitive adhesive layer, and flaps. The exterior film covering is thus a single layer in some areas and a double layer in others.
Another embodiment of the article of the invention comprises exterior film covering comp, ising a film and another film having projections, vibration çml~ting material, pressure sensitive adhesive layer, and flaps.
Another embodiment ofthe article ofthe invention cGn""ises exterior film covering co~.~p~;s;ng film seg.\.- .1 and film, vibration ~ttçn..~ting material, adhesive layer, and hole.
Another embodiment of the article of the invention co",p,ises an exterior film covering comprising film segn..~nl and pelr~laled film having pelro,~lions,vibration ~tten.l~ting material, and structured pressure sensitive adhesive layer, having projections and flaps.
Another embodiment of the article of the invention comprises exterior film covering, vibration attçn.latin~ material, and pressure sensitive adhesive layer.
Fig. 6a illustrates a cross-sectional view of the article of the invention co""),i~i~,g exterior film covering 282, vibration ~ttçn..~ting material 286, and pressure sensitive adhesive layer 288. Protrusions 284 extend from the inner surface of the exterior film covering in a direction towards the interior of the article.
Fig. 6b illustrates a cross-sectional view of an article of invention comprisingexterior film covering 290, vibration attçnU~ting material 294, pressure sensitive CA 02248828 1998-o9-o9 ~ adhesive layer 296, and flaps 298. Protrusions 292 extend from the outer surface of the exterior film covering 290 in a direction away from the interior of the article.
Fig. 6c illustrates a cross-sectionql view of an atticle of the invention coln~lis;ng exterior film covering 300, vibration att~n~l~ting material 304, pressure sensitive adhesive layer 306, and flaps 302.
Fig. 7a illustrates a cross-sectional view of an article of the invention co,n~ i, g an exterior film covering which is formed from film layers 308, 310, and 312; vibration attçn~l~ting material 314, p~essule sensitive adhesive layer 316, and flaps 318.
Fig. 7b illustrates a cross-sectional view of the article of the invention co,~ ;ng exterior film covering 320, vibration ~tt~m~ting material 322, vibration ~ttçn~tine material 326 which is di~e~enl than that of 322, interior film divider 324 having p~ alions 328, pressure sensitive adhesive layer 330, and flaps 332.
Fig. 7c illustrates a cross-sectional view of an article of the invention comprising vibration ~tten~ting material 334 and another vibration ~ttçnuatine material 336, a pressure sensitive adhesive layer 338, and flaps 340. An exterior film covering is present which is in some area a single layer and in other areas a double layer. The exterior film covering is a single layer where film 348 contarts vibration ~qttçn~qtin~ material 334. However, the exterior film covering is a double layer where film layer 348 contacts film seg~.~enl 344 and also where film layer 348 contacts film segmçnt 346. Film segm~nt 342 which divides vibration ~ttçnll~tingmaterial 334 and 336 is considered to be an interior film divider. Thus, one contimlouC film having film Se~m~nt~ 342, 344, and 346, in some places is considered to be part of the exterior film covering and in others an interior film divider. Film 348 is always considered to be a layer of the exterior film covering.
Fig. 8a illustrates a cross-sectional view of the article of the invention comprising exterior film covering 350, vibration att~n~~~ting material 352, flaps 354 and pressure sensitive adhesive layer 353.
Fig. 8b illustrates a cross-sectional view of the article of the invention coll")l;sing exterior film covering 360, vibration ~ttçn~ating material 356, a W 097/38237 PCT~US97/05827 chemically di~le.ll vibration ~tten~l~ting material 358, flaps 362, and pressure sensitive adhesive layer 355.
Fig. 8c illustrates a cross-section~l view of two articles of the invention joined by a layer of adhesive. One article COIIIIJ1;~S exterior film covering 364 and vibration ~ttçn-J~ting material 366. The other article co~ )lises exterior Im covering 370 and vibration attçn~ting material 368. The exterior films 364 and 370 are of dilTe,e--l chemical compositions. The vibration ~tt~m.~tin~ materials 366 and 368 are of di~erenl ch~miC~l compositions. The exterior film cover 370 has an adhesive layer 371 thereon. The flaps are id~.ntified as 372.
Fig. 8d illustrates a cross-sectional view of two articles of the invention joined together. One article co...~,.ises exterior film covering 382 and vibration att~nl)?tin~ material 376. The other article co-ll~li3es exterior film covering 378 and vibration attçn~tin~ material 380. The exterior films 382 and 378 are of dilrere..L Che~ILC~I compositions. The vibration ~tt~.nl.~ting materials 376 and 380 are of di~e- elll chemical compositions. The articles are joined via a multilayer construction comprising adhesive layers 382 and 386 and inner film layer 384.
Exterior film layer 378 has a layer of adhesive 381 thereon. The flaps are identified as 374.
Fig. 9a illustrates a cross-sectional view of the article of the invention comprising exterior film covering 390, vibration ~tt~ml~ting material 394, flaps 392, and pressure sensitive adhesive layer 396.
Fig. 9b illustrates a cross-sectional view of two articles of the invention joined together. The first article colll~)lises exterior film covering 398 and vibration ?ttem~ting material 400. The second article co-.lplises exterior film covering 404, vibration ~ttçn-l~ting material 406, and pressure sensitive adhesive layer 408. The articles are joined via adhesive 402.
Fig. 9c illustrates a cross-sectional view of two articles of the invention joined together via their vibration atten~ting materials. The first article comprises exterior film covering 410 and vibration att~m~ting material 412. The second article co--.~,lises exterior film covering 416 and vibration ~ttenn~ting material 414.

.

W O 97/38237 PCT~US97/05827 Fig. 9d illustrates a cross-sectional view of the article of the invention comprising an exterior film covering 418, a vibration atteml~ting material 420, an interior film divider 422, a di~re,ll vibration ~tt~n-l~tin~ material 424, and apressure sensitive adhesive layer 426.
Fig. 10a illustrates a cross-section~l view of an article ofthe invention co~ ,l;s;l~g exterior film covering 428, vibration attçml~tin~ material 430, andpressure sensitive adhesive layer 434. The vibration attçn~ in~ material col-~aills high modnl~lc filler particles 432.
Fig. lOb illustrates a cross-sectional view of an article of the invention comprising exterior film covering 436, vibration att~m.~ting material 438, and pressure sensitive adhesive layer 442. The vibration ~tten~l~ting material cGnla;l s high mf dnlllc filler particles 440.
Fig. 10c illustrates a cross-sçction~l view of an article of the invention con~plising exterior film covering 446 ,vibration ~tteml~ting material 448, and pressure sensitive adhesive layer 452. The vibration attçnllating material contains high modulus filler object 450.
Fig. 11 illustrates a cross-sectional view of the article of the invention collll~lis;t~g exterior film covering cOllllJl;sil1g film se~ 454, 455, and 459,vibration ~tteml~ting material 456, 458, and 460, and pressure sensitive adhesive layers 460, 462, and 464, and interior film dividers 470 and 468. The same contimlQ~ls film functions as part ofthe exterior film covering (se.g,..~.lc 455, 4s4 and 459) and in other areas ofthe article as the interior film divider (se~ç~n~ 470 and 468).
Method of M~kin~p the Article of the Invention The article of the invention can be prepa~ ed by a number of methods such that vibration attçnu~ting material is at least partially en~losed by an exterior film covering. A specific article of the invention can be made, for example, by providing two layers of a desired film (typically a polymeric film such as a polyethylene or polyester film) of the same dim~n~ions~ heat sealing the edges of the films together on three sides to forrn a bag, filling the bag with an uncured vibration attçnu~ting material, sealing the films along the rem~ining side of the bag, thus .. . .

~ enclosing the vibration stt~nufltine material in a "pillow" and optionally curing the vibration ~sttçnu~sting material by app~ - iate means such as by subjecting the sealed bag to heat or radiation, for e - , le. An initiator can be added to the vibration -s-ttçn~-s-ting material prior to cure if desired. The rçe~.lt~nt article can optionally have an adhesive applied to one or more sides to fs~ilitste application of the article to a surface.
Another method of making a specific article of the invention, for CA ple, is by blow molding a film (such as a polymeric film, for example) into a desiredshape, removing the shaped film from the mold, and filling the shaped film with an uncured vibration attçnllating material. The vibration ~ttçn-l~ting material can be optionally cured by a number of methods, such as those described above. An additional film layer(s) and/or film seg~ (s) may optionally be lsminsted over some or all of the c~.l osed vibration ~s~ttAn~lstinp material. An adhesive layer may optionally be coated over some or all of the film coating and/or optionally an adhesive may be coated on some or all of any exposed vibration att~nu~stinp material.
A layer of adhesive (such as a pressure sensitive adhesive) may be coated on an outer surface of the exterior film covering of the article and/or on an exposed surface of vibration stten--stin~ material. Optionally a layer of adhesive may be coated on at least a portion of an inner surface of the exterior film covering prior to addition of the vibration ~stt~n~l~ting material. In addition a layer of adhesive may be coated on at least a portion of one or both surfaces of an interior film divider which separates one area of vibration att~n--~ting material from another. An interior divider may be included in the article by, for ~ le, first ~Illling a molded exterior film covering, filling the molded exterior covering partially with a vibration attçn-)~tin~ material, inse- ling a layer of a dif~elenl film over the vibration~ttçn-.~ting material which will serve as the interior film divider, adding a layer of a dil~renl vibration attenll~ting material over the interior film divider, followed by cure, and optionally a layer of adhesive over the exposed vibration att~m~ating material. Particulate and other additives may optionally be added to the vibration attçn-.~ting material prior to enclosing with the exterior film cover although in some .. .. . ..

W 097/38237 PCTnUS97/05827 ~ situations they may be added to the vibration attçm-~tin~ material after it is inserted into a molded exterior film covering, for example. The vibration ~tt~n.nqtin~
material when only partially enclQsed by the exterior film covering must not be in a liquid state such that it can flow out of its enclosure. The vibration ~qtten~qti~
material is thus typically a solid or gel which is bonded to the exterior film covering, typically due to the possible adhesive nature of the vibration ~ttçn..qting material ~Itholl~h this may be due to a separate adhesive which may optionally be used tobond the vibration ~tten~l~qting material to the exterior film covering.
These methods and articles described are not meant to be limiting Uses of the Articles of the Invention The articles of the invention can be used for numerous applications.
F. ~ 'es of suitable applications include, for structures selected from the group con~;sling of disk drive ~c~F.."hliçc, optical disk drives, compact disk acsemhlie appliql~ces~ transport vehicles, ~1tomobiles, doors, drawers, hoods, comruters, printed circuit boards, and test eq~irm~nt.

The article of the invention can, for t,~ c, be placed with, on or within a structure to be ~qttçn~qtecl The article may be adhered to the structure via an 20 adhesive. Alternatively it may be placed or wedged in its place of use without an adhesive if the structure of the article is conducive to such pl,qcP.ment Other methods of pl ~,cPm~nt are also possible.
The shape of the article of the invention, selection of polymeric or non-polymeric films, selection of vibration qttçn~.q~in~ material(s), additives, etc. are all based on the end use pe,r~"",ance and envhor.. ~ ql requiremenls of the article.
The article of the invention can be as thin or as thick as needed for a given application.
For most applications the article has a thickness of about 0.025 to 50mm, preferably about 0.125 to 25mm, and most plefelably about 0.125 to about 1 7.5mm, For most applications the article has a width of about 1.25 to 75mm, preferably about 2.5mm to 50mm, and most pler~lably about Smm to about WO 97t38237 PCT/US97/05827 ~ 37.5mm. For most applicalions the article has a length of about 1.25mm to 75 mm, prere,2,bly about 2.5 to 50mm, and most prerelably about 1.35 to about 37.5mm.
For most applications the article has an exterior film covering with a thickness of about 0.005 to 1.25mm, preferably about 0.025 to 0.75mm, and most ple~-~bly about 0.025 to about 0.375mm.
When present, an interior film divider typically has a thickness of about 0.005 to about 1.25mm, preferably about 0.005 to about 0.075mm, most preferably about 0.01 to about 0.375mm.
For a typical disk drive applic~lion for dqfnp;~ a voice coil motor between the top magnet plate and the disk drive cover, the exterior film covering typically ranges from about 0.0127mm (0.5mil) thickness to about 0.508 to 0.762 (20 to 30 mils) thiclrnçse, pre~,ably about 0.025mm(1 mil) to 0.25mm(10 mils), and most p~e~l~bly about 0.025mm(1 mil) to about 0.178(7 mils) thic~ness. The vibration ~ttemlating material llL~l~ness is dep~ndent upon the particular application. For a typical disk drive application, the vibration ~ttçn.-~tine material nominal thicl~nçs~
(~Csllmin~ a basic tn.nç~ted flat top/flat bottom pyramid shape damper) is typically in the range from about 0.0127 mrn (0.5 mil) lhichRss to about 12.7mm (500 mils)th;~~nf~.~s Most applications typically require a damper design with a damping material thiclrness of about 0.25mm (10 mil) to about Smm (200 mils).
Preferably the vibration ~ttçnu~ting material has a glass transition te~ )cl alul e of less than about 60~C at 1 Hz., more pre~- ~bly less than about 45~C
at 1 Hz, and most preferably less than about 38~C at 1 Hz.
The overall geometry of the article of the invention will vary with the degree of vibration attçnu~tion required for an application. For a typical disk drive, and for a vibration ~ttem~ting article applied between the top magnet plate of the actuator motor and the top cover and that is designed to have a trunc~ted (flat top)Mat bottom pyramid shape, and where the top of the damper is from 50-80% of the surface area of the bottom of the article, the top of the article will have a top flat surface area that ranges from about 6.45 square mm (0.1" squared) to 2581 squaremm (2" squared). The damper for this application is also under a degree of co~llpres~ion, typically ranging from about .5% to 50% after in~t~ tion.

E~amPle The invention has been described with refe~ ce to various specific and pre~c~led embodiments and will be further described by rcrelence to the following det~iled example It is understood, however, that there are many extensions, variations, and modifications on the basic theme of the present invention beyondthat shown in the e~...rle and det~;led description, which are within the spirit and scope of the present invention E~ample 1 - Single Layer Damper:
A 0 10 mm thick amorphous polyester film was set over a heat re~;sl~ l mold and heated to allow the film to take the shape of the mold The shape of themold was a truncated pyramid measuring 12 mm x 12 mm at the base, appro~ alely 8 mm x 8 mm at the top, and appl ~-I.ldtely 4 mm thick The shaped film was removed from the mold and filled with a partially photopol~me. zed mixture of by weight 41 parts of isooctyl acrylate 59 parts of isbornyl acrylate 0 04 part of 2,2-~innethoxy-2-phenyl acetophçnon~ which was obtained as Irgacure~65 1 from Ciba Geigy The partial photopoly.nel.~---g of the mixture was acco...plished in an inert (nitrogen) atmosphere using a bank of 40-watt fluorescc--~ black lights to provide a syrup of a viscosity (Brookfield) of about 3000 cps Prior to filling the shaped film, 0.22 part of hexane diol diacrylate and an -~tlition~l 0.12 part of"Irgacure" 651 were added to the partially polylllcli~ed mixture A 0 025 mm thick film of 3M
SCotcl ~mpTM ISD-262 acrylic polymer on a 0 05 mm thick polyester release liner was l~min~ted to the 12 mm x 12 mm base ofthe truncated pyramid shaped film with the partially poly.nc ized mixture in intim~te contact with the Scotçhd~mplM
ISD-262 polymer The filled shaped film was irradiated with the same fluorescent lamps for 10 minutes to complete the pOI~/lllcl izalion of the partially polymerized .

W 097138237 PCTrUS97/05827 mixture. The polyester release liner was then removed. The res ~lting article was a single layer ~ttenuatQr ready for testing.

Comparative E~ample I - Current Generation Damper Design A damper currently available from 3M and used for a disk drive actuator application is designqted as follows:

Two P~lnt Damper Design:
Part one: Applo~;...~t~ly 4mm thick ISD-110 ~1~."~ material with 0.05mm ISD-112 ds~.~pil-~ material layer ~tta< hed on the base and ap~ xi,l,dlely 1 Smm x 1 Smm length and width die cut rectanEle.
Part two: 28mm x 28mm die cut part of 3M VC-134 polyethylene release film 0.016 mm with a 0.04 mm thick acrylic pressure sensitive adhesive on one surface.
The Example 1 and the CGnlpa ~ e Example 1 dal-~;)c- ~ as pr~pd~ed above were tested in the following configurations:
Configuration 1-The disk drive cover of the designqted test drive was removed. One of the E~ampl~s 1 dampers was ~ttnehed to the top surface of the msgnetie plate of the act-l~tQr motor so that the base of the damper was in contact with the plate. It was attached such that when the cover was re~ttAçh~l1 the damper would be coll~pl~s~ed by at least 1 percent ofthe d~-pel~ total thietrness Configuration 2-The same as Configuration 1 except that two Example 1 dampers were ~tt~~hed side by side on the top surface of the mqgnetic plate.
Configuration 3-The same as Configuration 1 except that one Colllpa,dLi~e Example 1 damper was used in the drive. Part one was ~tt~ched to the top surfaceof the m~netic plate and Part two was ~ttached to the inner surface of the drivecover via its adhesive in a position which allowed its adhesive free side to directly contact Part one when the cover was re~tt;lch.od Configuration 4-The disk drive without using any darnper.
The disk drive cover ofthe decign~ted test drive was removed. One or two Example 1 and Col.-pa- a~i~e Example 1 darnpers were added to the top portion of -40~

W097/38237 PCT~US97/05827 ~ the actuator motor on the top magnet plate. The dampers were specifically attached to the magnet plate of the actuator motor such that when the cover was re~tt~che(l the darnper would be co",~ ssed by at least 1% ofthe dampers total th~ ness for all dçci~ The drive was tested at 20-30~C in an ~r ~-ctic chqmber.
The drive was then placed into a test room for acoustic meas~rt;,nenls and - started. The drive reached the desired ope.alillg spindle speed and a computer cormected to the disk drive sent instructions to the drive to allow the actuatormotor to do random movements moving the read-write heads quickly over a series of data or servo tracks. This movement of the actuator created vibrations in theactuator assembly and other areas of the drive, leading to acoustical noise above the levels when the actu~tQr in the drive is not opelalii~g~ Adding a damper to the actuator asse.llbly for this test between the cover and actuator reduced this noise.
Monitoring the acoustical levels of the drive was a microphone (placed appro,.;...~tely 2 feet from the drive) ~ttr~hed to a Bruel and Kj~r frequency analyzer. The test measured the noise in dBA over a frequency range in Hz. This tester allowed collection of data for the relative acoustic~l pel roll.lance of the drive with no actuator dampers and the Example 1 and Co~pal ~live Example 1 dampers.
Results are reported in the table below. Configuration 1 is identified in the table as "1 x Example Damper" Configuration 2 is id~ntified in the table as "2 x F.Y~nnple Damper", Configuration 3 is identified in the table as "Co.llpa,ali~e Example Damper", and Configuration 4 is identified in the table as "No Damper".

.

W 0 97138237 PCTAUS97/0~827 FREQUENCY Co.. ,l,a,a~ e I x 2 x No Example Example Example Damper Damper Damper Damper 200 2.09 13.55 12.28 30.13 250 17.07 20.25 19.43 19.66 315 11.4~ 16.49 17.07 17.50 400 15.90 19.90 16.86 17.92 - 500 23.05 23.40 20.15 21.54 630 26.20 26.20 21.61 24.62 800 24.46 23.54 17.92 22.~3 1000 24.76 28.88 25.87 30.36 1250 29.89 33.30 33.18 40.05 1600 25.47 27.33 26.46 40.43 2000 30.83 30.34 29.37 35.82 2500 32.34 32.95 29.19 28.41 3150 27.47 28.53 27.37 30.29 4000 32.57 37.61 30.88 37.13 5000 31.91 34.10 32.78 30.57 6300 20.39 18.65 18.11 22.18 8000 ~9.66 21.73 18.04 21.99 10000 14.53 15.05 12.51 14.89 12500 13.03 13.95 12.30 13.15 16000 12.35 10.49 9.43 11.90 20000 9.90 6.07 5.53 8.70 The data in the above table shows that the dampers of the invention have exce~ nt cl~...pi~g pe-~..~ ce as compared to the colll?araL,~e damper example.
Either one or two smaller Example 1 dampers provided nearly the same damping benefit or improved p~l~.. ance as cGn~pared to the larger colllpal~Li~e damper.So, in addition to the benefits associated with the example dampers design for environm~nt~l protection, cleanability, one piece design, etc., the example dampers have excellent damping pel~o~ll,ance.

The foregoing detailed description and examples have been given for clarity of underst~n-iing only. No llnnecçss~ry limitations are to be understood thelefiolll.
The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be in~.h~ded within the invention defined by the claims. Varying damper designs may also provide for better dal"pil-g results than shown by the above example.

W O 97/38237 PCTnUS97/05827 E~ample 2 - Outgassing Ev~luation In order to dçmonctrate the improved outg~Ccing pe.ro~ ce ofthe novel dampers as colll~ared to control d~llpe~ ~ not having an exterior film covering,S sample dal,lpct~ ofthe invention were pl.,palcd and tested for Olltg~CCi~g pcl~,lll~ce.
Four single layer dampers were prepa~ed as described in Example 1. The polyester outer film was removed from two of the dampers leaving just the viccoelsetic d~n ring polymer in the shape of the trunrqted p,vramid in order toprovide the Control Samples. The le ~;n;~g two dampers with their coverings intact were ide~ntifif~A as the Ex. 1 dampers.
Testing was done by placing the darnpers in separate clean preweighed qh~mimlnl pans with the base of the damper in contact with the bottom surface ofthe test pan. The dampers were weighed on a scale in the test pans and then placed into a Class 100 Cleanroom convection oven that had been prehcd~ed to the desired test tellli)c~ re, 1 50~C. After 2 hours in the oven, the sal~lpl e s were removed from the oven, placed into a dessicator for 30 minutes to allow to cool and stabilize, and then reweighed to determine the weight loss of each sample.
The average weight loss of the 2 samples for each condition are showed in the following table.

SamPles % Wei~ht Loss Control 0.336 Ex. 1 0.167 The data for the outg~e,eing weight loss shows that that the samples ofthe invention have improved o~t~eeing p~lrolll~ ce as the %
weight loss is less than the s~mples of the control. The above data shows that the novel damper design of the invention does provide for an improved olltg~csing design ae compared to the Control Samples, for example as the part is used for disk drive applications.

.. .. . ~ .. .. . . .

The foregoing detailed description and examples have been given for clarity of understanding only. No ~.nl~ecess~i y limitations are to be understood therefrom.
The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be in~luded ~,vithin the invention defined by the claims. Varying damper designs may also provide for better outg~ing results thanshown by the above example.

Claims (11)

It is claimed:

1. An article comprising:
(a) a vibration attenuating material, wherein the vibration attenuating material has a storage modulus greater than about 6.9x10 3 Pascals and a loss factor greater than about 0.01 at 25°C and 1 Hertz, wherein the vibration attenuating material has a surface and an interior;
(b) an exterior film covering, wherein the exterior film covering film has a tensile modulus greater than about 6.9x10 3 Pascals at 25°C and 50% relative humidity, wherein the exterior film covering comprises one or more of the following:
(i) a film;
(ii) a film segment;
wherein the vibration attenuating material surface is at least partially enclosed by the exterior film covering;
wherein an inner surface of the exterior film covering conforms to the surface of the vibration attenuating material that it is at least partially enclosing;
wherein at least a portion of the surface of the enclosed vibration attenuating material has a three dimensional shape;
(c) optionally one or more interior film dividers, wherein each interior film divider has a tensile modulus greater than about 6.9x10 3 Pascals at 25°C and 50%
relative humidity, wherein each interior film divider comprises one or more of the following:
(i) a film;
(ii) a film segment;
wherein each interior film divider separates at least a portion of the vibrationattenuating material from another portion of the vibration attenuating material; and (d) optionally a layer of adhesive coated on one or more of the following:
(i) at least a portion of a surface of the exterior film covering;
(ii) at least a portion of a surface of any interior film divider, if present;

(iii) at least a portion of any vibration attenuating material which is not enclosed by the exterior film covering;
wherein when the vibration attenuating material is completely enclosed by the exterior film covering a layer of adhesive must be coated on at least a portion of an outer surface of the exterior film covering.

2. The article of claim 1 wherein the vibration attenuating material is completely enclosed by the exterior film covering.

3. The article of claim 1 wherein the vibration attenuating material is partially enclosed by the exterior film covering and about 50 to about 99 percent of the surface of the vibration attenuating material is enclosed by the exterior film covering.

4. The article of claim 1 wherein the vibration attenuating material is partially enclosed by the exterior film covering except for one flat surface of the vibration attenuating material and wherein an adhesive layer is present which is coated over the flat surface which is not enclosed by the exterior film covering.

5. The article of claim 1 wherein the vibration attenuating material has a shapeselected from the group consisting of cubes, rings, pyramids, prisms, truncated pyramids, stepped pyramids, stepped rectangles, cylinders, cones, spheres, hemispheres, and pillows; wherein the exterior film covering comprises film layer(s) and/or film segment(s) each independently selected from the group consisting of crystalline polyester, amorphous polyester, polyimide, polyamide, polyethylene, polypropylene, acrylic, phenolic, polyvinyl chloride, polyurethane, polystyrene,fluorinated polymer films, polyvinyl acetates, and nylon; and wherein the vibration attenuating material is selected from the group consisting of urethane rubbers, silicone rubbers, nitrile rubbers, butyl rubbers, acrylic rubbers, natural rubbers, styrene-butadiene rubbers, polyesters, polyurethanes, polyamides, ethylene-vinylacetate copolymers, polyvinyl butyral, polyvinyl butyral-polyvinyl acetate copolymers, epoxy-acrylate interpenetrating networks, polyacrylates, polycarbonates, polyetherimides, polyesters, polysulfones, polystyrenes, acrylonitrile-butadiene-styrene block copolymers, polypropylenes, acetal polymers, polyamides, polyvinyl chlorides, polyethylenes, and combinations thereof.

6. The article of claim 1 wherein the vibration attenuating material has a glasstransition temperature of less than about 60°C at 1 Hz, wherein the article has a thickness of about 0.025 to about 50mm, a length of about 1.25 to about 75mm, and a width of about 1.25 to about 75mm, and wherein the exterior film covering has a thickness of about 0.005 to about 1.25mm, wherein the exterior film covering may have one or more features selected from the group consisting of holes, slits, impressions, and protrusions, and wherein at least one interior film divider maypresent which may have one or more features present selected from the group consisting of holes, slits, impressions, and protrusions.

7. A method of attenuating vibration in a structure comprising the steps of:

(i) placing an attenuating article of any of claims 1 to 6 with, on, or within the structure; and (ii) compressing the article from 0.5 to 50%.

8. The method of claim 7 wherein the structure is selected from the group consisting of disk drive assemblies, optical disk drives, compact disk assemblies, appliances, transport vehicles, automobiles, doors, drawers, hoods, computers, printed circuit boards, and test equipment.

9. The method of claim 7 wherein the structure is a disk drive assembly, whereinthe article is positioned between and in contact with a magnet plate of an actuator voice coil motor assembly and at least one of the following:(i) a disk drive cover;
(ii) a disk drive base.

10. The method of claim 7 wherein the structure is selected from the group consisting of (i) a door and door frame assembly wherein the article is positioned between the door and the door frame such that the door will contact the article during actuation and a (ii) a drawer and a drawer frame assembly wherein the article is positioned between the drawer and the drawer frame such that the drawer will contact the article during actuation.

11. A structure having an attenuating article positioned in relation to the structure such that the attenuating article is capable of attenuating the vibration of thestructure in at least one vibrational mode, wherein the article comprises (a) a vibration attenuating material, wherein the vibration attenuating material has a storage modulus greater than about 6.9x10 3 Pascals and a loss factor greater than about 0.01 at 25°C and 1 Hertz, wherein the vibration attenuating material has a surface and an interior;
(b) an exterior film covering, wherein the exterior film covering film has a tensile modulus greater than about 6.9x10 3 Pascals at 25°C and 50% relative humidity, wherein the exterior film covering comprising one or more of the following:
(i) a film;
(ii) a film segment;
wherein the vibration attenuating material surface is at least partially enclosed by the exterior film covering;
wherein an inner surface of the exterior film covering substantially conforms to the surface of the vibration attenuating material that it is at least partially enclosing;
wherein at least a portion of the surface of the enclosed vibration attenuating material has a three dimensional shape;
(c) optionally one or more interior film dividers, wherein each interior film divider has a tensile modulus greater than about 6.9x10 3 Pascals at 25°C and 50%
relative humidity, wherein each interior film divider comprises one or more of the following:

(i) a film;
(ii) a film segment;
wherein each interior film divider separates at least a portion of the vibrationdamping material from another portion of the vibration damping material; and (d) optionally a layer of adhesive coated on one or more of the following:
(i) at least a portion of a surface of the exterior film covering;
(ii) at least a portion of a surface of any interior film divider, if present;
(iii) at least a portion of any vibration attenuating material which is not enclosed by the exterior film covering.