CA1324477C - Shaped articles from polyester and cellulose ester compositions - Google Patents

Abstract

Abstract SHAPED ARTICLES FROM POLYESTER AND
CELLULOSE ESTER COMPOSITIONS

Disclosed are shaped articles comprising a continuous polyester phase having dispersed therein microbeads of cellulose acetate which are at least partially bordered by void space, the microbeads of cellulose acetate being poresent in an amount of about 10-30% by weight based on the weight of said polyester, said void space occupying about 2-50% by volume of said shaped article. Such articles have excellent physical properties, especially optical properties, and are useful in such applications as paper substitutes, for example.

Description

SHAPED ARTICLES FROM POLYESTER AND
CELLULOSE ESTER COMPOSITIONS

Technical Field The present invention is directed to shaped articles such as films, sheets, bottles, tubes, fibers and rods having a polyester continuou~ phase containing cellulose ester microbead~ di_persed therein which are at least partially bordered by 10 voids. The articles have unique properties of `
texture, opaquene_s, ~hiteness in the absence of colorants, and generally 8Ood physical properties _uch as tensile properties~

Back~round of the Inv~ntion Blends of linear polyeQter_ with other incompatible material~ of organic or inorganic nature to form microvoided structure_ are well-known ln the art. U.S. Patent No. 3,154,461 diQcloses, for ~xample, the linear polyester, poly(ethylene terephtbalate), blend~d with, $ot example, calcium carbonate. U.S. Patent No. 3,944,699 diQclo~es blends of linear polyester, preferably poly(ethylene terephthalat~) with 3 to 2~S of organic materlal ~uch a~ ethylcnQ or propylene polymer. U.S. Patent No.
3,640,944 alao di~close~ the u~e of poly(ethylene terephthalate) but blended ~ith 8~ organlc materlal such as polyqulfon~ or polyt4-methyl,l-pentene).
U.S. Patent No. 4,37~,616 dl~close~ a blend o~ -polypropylene to serve a~ the matrix with a ~mall percentage of another and incompatlble organlc material, nylon, to lnitlate mlcrovoldlng ln the polypropylene matrix. U.K. Patent Specification 1,563,591 disclose~ linear polyester polymers, and partlcularly poly(ethylene terephthalate), for making~
an opaque thermopla~tic film _upport in which have ~ -. ~ .
.~,'. ' been blended finely divided particles of barium sulfate together with a void-promoting polyolefin, sueh as polyethylene, polypropylene and poly-4-methyl-1-pentene.
The above-mentioned patents show that it ia known to use incompatible blends to form films having paper-like characteristics a$ter such blends have been extruded into films and the films have been quenched, biaxially oriented and heat set. The minor 1~ component of the blend, due to its incompatibility with the mfl~or component of the blend, upon melt extrusion into film forms generally spher~cal particles each of which initiates a microvoid in the resulting matrix formed by the ma~or component. The melting points of the void initiating particles, in the use of organic materials, Qhould be above the glas~ transition temperature of the ma~or component of the blend and particularly at the temperature of ~iaxial orientation~
As indicated in U.S~ Patent No. 4,377,616, ~pherlcal particles initiate void~ of unusual regularity and orientation in a qtratified rQlationship throughout the matrlx material after biaxial orientation of the extruded film. Eaeh vold tends to be of like shape, not necessarily of like size sinc~ the size dQpends upon the ~lze of the particle.
Ideally, each void assumes a shape defined by two opposed and edge contacting concave disks. In other word8, the volds tend to have a lens-like or biconvex shape. The voids are oriented so that the two ma~or dimensions are aligned in correspondence with the direction of orientation of the film structure. One ma~or dimension is aligned with machine direction orientation, a second ma~or dimension is aligned with the transverse direction orientation, and a minor ' '' `

` 1 324477 dimension approximately corresponds to the cross-section dimension of the void-initiating particle.
The voids generally tend to be closed cells, and thus there is virtually no path open from one side of a biaxially oriented film to the other side through which liquid or gas can traverse.
Upon biaxial orientation of the resulting extruded film, the film becomes white and opaque, the :`
opacity resulting from light being scattered from the ualls of the microvoids~ The transmission of light through the ~ilm beco~es leQsened with increased number and with increased Qi2e of the microvoids relative to the _i~e of a particle within each microvoid~
Also, upon biaxial orientation, a matte finiQh on the qurfaee of the film re~ult~, a~ discu_Qed in U.S.
Patent No~ 3,154,461~ The particle~ ad~acent the _urface_ of the film tend to be incompre~ible and thu_ form pro~ectionq ulthout rupturlng the ~urface~
Such matte finiQhe-q enable the film to be wrltten upon ~ith pencil or ~ith ink~, crayon~, and the llke~
Although t~e filmQ dlscu_Qed so far are generally ~hlte and opaque, ~uitable dye~ may be u~ed either in ~hat ~ill become the matrix polymer or in the void lnltiatlng particle~ V.S. Patent No. 4,37~,616 `
polnt~ out that lntere~tlng effectQ can be achieved by the u~e of ~pheres of different color~ or by the u~e of ~phereQ of different color ab~orption or ~ ~`
reflectance. The li8ht ~cattered in a particular void may additionally either be abqorbed or reflected `
by the void initlating ~phere and a ~eparate color contribution i~ made to the light ~cattering in each void~
U.S~ Patent No~ 4,377,616 di~close_ that preferred particle ~ize of a void initiatin8 sphere ` 1 324477 may be about 0.1 to about 10 microns, and that preferred particle size range from about 0.75 to about 2 microns. U.S. Patent No. 3,154,461 specifies that a range of sizes may be approximately 0.3 micron to approximately 20 microns, and that when calcium carbonate is used, its Qize may range from 1 to 5 microns.
U.S. Patent No. 3,944,699, for example, indicates that the linear polyester component of the film may comprise any thermoplastic film $orming polye~ter uhich may be produced by condensing one or more dicarboxylic acids or a louer alkyl diester thereof, _uch a-~ terephthalic acid, isophthaliC acid, 2,5-,2,6- or 2,~-naphthalene dicarboxylic acid, succinlc acid, sebacic acid, adipic acid, azelaic acid, bibenzoic acid, and hexahydroterephthalic acid, os bi~-p-carboxy phenoxy ethane, with one or more glycolg. Such glycols may include ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol~ Al_o, a copolyester of any of the above-indicated materialQ may be used.
~he preferred polye~ter i~ poly(ethylene terephthalate).
U.S. Patent No. 3,944,699 al~o indicates that the -extru-~ion, quenching and ~tr~tching of the film may be effect~d by any proce~ which i~ known in the art for producing oriented film, ~uch as by a flat fllm proceQ~ or a bubble or tubular proce~a. The flat fllm proce~ involve~ extruding the blend throu~h 8 ` `
sllt dye and rapidly quQnching the extruded web upon a chllled ca~ting drum ~o that the polye~ter component of the film iQ quenched into the amorphous ~tate. The quenched fllm i~ then biaxially orlented by ~tretchlng in mutually perpendicular directions at a temperature above the glaQ~ tranQitlon temperature of the polyeQter. The fllm may be ~tretched ln one direction and ~hen in a second direction or may be -simultaneously stretched in both directions. After the film has been stretched it is heat set by heatlng to a temperature sufficient to crystallize the polyester while restraining the film against retraction in both directions of stretching.
Paper is essentially a non-~oven sheet of more or less randomly arrayed fibers~ The key properties of these structures are opacity, texture, strength, and stability. Obviously, fiber technology evolved synergistically with paper, and today we have a variety of synthetic fibers and synthetic papers. In both areas, hoever, the synthetic material~ have never quite matched the cellulose-based natural polymers, like cotton for fibers and cellulo~e pulp9 for papers~ On the other hand, the natural polymer~ `
are generally weaker and less stable~ A -Qerious problem, for example, is brightness reversion or fadin8 of papers and ~ibers. The present invention ~ `
advance_ the state of these prior arts~
Although there ar~ many ways ~o produce opaque media, thi_ inventlon i_ concerned with creating opacity by Qtretchlng or orlentlng plastlc materials to induce microvolds which _catter light, preferably ~hite llght. A large body of prior art deals with this technique, wherein a plurality of inorganic solid particle~ are used as the di_perQed pha~e, around ~hich the microvold~ form. Some ~ignificant problem-Q assoclated ith this approach are:
(1) agglomeration and particle ~ize control, (2) abrasive ear of extrusion equipment, guides~ and cutters, ~3) hi8h ~pecific gravity of these solids, (4) poor vold nucleation around the ~olid particle~ `
due to the lo thermal contraction of solid~ relative ~-to liquids and polymer wetting and adhesion to the ~olid surfaces, (5) cost of these materials on a -,.,' ' volume bas~s, and (6~ handling and processing problems in general. In every case, the inventlon reduces or eliminates the problem.
The prior art also teaches a variety of methods of creating surface texture. Often the surface is roughened by physical means like abrasion, crimping, etc. Nany chemical methods are also used to react with, etch, or otherwise alter the surface. Flame, electricâl corona, and electromagnetic radiations are often employed~ ~oatin8 technology is well advanced for filling and whitening, and of~en lnorganic materials are ma~or components of these coatings.
Even if the orientation or stretching stap i9 eliminated, a coating step is required. Not only do most of the problems above remain, but neu ones are created in such areas as adhesion, uniformity, and coating stability~
The cited prior are concentrates on ~ynthetic paper compositions and methods of manufacturing Idirectly related to t~i~ invention, namely compo~itlons of matter involvlng polyesters and/or colluloQe estQrs, ~tretching lncompatible/lmmi~cible thermopla~tlc blend~ to create voided Qtruetures wlth or without texture, and some of the properties and problem~ a~Qociated wlth the use of lnorganic, nonmelting materlal~ The blend compositions and proce~ing methodQ of this invention constltute a ~igniflcant lmprovement over the immlscible polymer blend ~y-~tem~ found in the prior art. -`
De~criDtion of the Drawin~
In the dra~in89:
~ lgure 1 i~ a perQpective view in ~ection lllu~trating an embodiment of the present invention;
Figure 2 i~ a perspective view in ~ection illustrating another embodiment of the present invention;
"' . ~

Figure 3 is a perspective view illustra~lng still another embodiment of the present invention;
Figure 4 is a section of a shaped article in the form of a bottle;
Figure 5 is an enlarged section view illustrating a microbead of cellulose acetate entrapped in a void in a polyester continuou matrix;
Figure 6 is a sactional view taken along lines 6-6 of Figure 5;
Figure 7 is a sectional view ~imiliar to Figure 5 illustrating a modification of the present invention; `
and Figure 8 is a graphical representation illustrating how the slze of microbeads surrounding microbeads changes with respect to stretch ratlo.
Figures 9, 10 and 11 are photomicrograph~ of film compriQing a polya~ter continuous matrix, and cellulo_e e_ter microbead-Q at least psrtially bordered by void_~
~`
~eQc~E~ on of the Invention In accordance ~ith the preQent invention, ~haped article~ are provided ~hlch have unique propertie~
such a~ texture and opacity. The articleQ are e~pecially useful uhen in the form of ~ilm or ~heet material ~e~g~, aQ a paper substitute) or when in the `
form of a biaxially oriented bottle (beverage container)~ .
Referrin8 to the drawings, FlgurQ 1 illustrates a ~haped article in the form of a sheet 10 which has been biaxially oriented tbiaxially stretched, i.e., stretched ln both the longitudinal (X) snd transverse (Y) direction~], a~ indicated by the arrows. The ~heet 10 i~ lllustrated in Rection, showing microbead~ of celluloQe acetate 12 contained within circular vold~ 14 in the polyeQter continuous matrix 16. The voids 14 surrounding the microbeads 12 are theoretically doughnut-shaped, but are often of irregular shape. Sometimes two or more microbeads will be bordered by common voids, as illustrated in Figures 9, 10 and 11. Often, a line drawn perpendicular to and through the article will penetrate several voids and possibly some microbeads.
Figure 2 also illustrates a shaped article in the form of a sheet 20 which has been unidirectionally oriented (stretched in one direction only, as indicated by the arrow). Microbeads o$ cellulose acetate 22 are contained between microvoids ~4 and 24'. The microvoids in this instance form at oppo~ite ~ides o$ the microbeads as the sheet i9 stretched. Thue, if the stretching is done in the machine direction (X) ae indicated by the arrow, the voids ~ill form on the leading and trailing sides o$
the microbeads~ This is becauQe of the unldirectional orientation as opposed to the bidireetional orientation of the sheet ~hown in Figure 1. This is the only dif~erence between Figure 1 and 2. Note particularly the bumpy texture of the surfacee.
Figure 3 illuQtrates a ~haped article in the form of a fiber or rod 30 ~hich has been orlented by stretching in the length~ise (X) direction. The microbeads 32 of cellulose ester are bordered by microvoids 34 and 34.
Figure 4 illu~trates a section of the w811 of a shaped article 40 ~uch a~ a bottle or wire coating.
Due to the bidirectional orientatlon or stretching, the microvoid~ 42 are 8enerallY doughnut-shaped, surrounding the mlerobeads 44, in a manner similar to that sho~n in Figure 1~
Figure~ 5 and 6 are sectional views illustrating enlargement of a -~ection of a ~haped article `: "

- ~ 324477 according to this invention, microbead 50 being entrapped within polyester continuous matrix 52 and encircled by void 54. These structures result from tha shaped article being stretched in the X and Y
directions.
Figure 7 is a view similar ~o Figure S, except illustrating in enlarged form microbead 60 entrapped in polyester continuous matrix 62, having formed on opposite sides thereof microvoids 64 and 64', which ~ -~
are formed as the shaped article ia stretched in the direction of the arrow X
Figure 8 is sn enlargement illustrating the manner in ~hich microvoid~ are formed in the polyes~er continuous matrix as the shaped article is 15 stretched or oriented. The formation of the - `
microvoids 70 and 70` around microbead~ 72 i9 .`` . `
illustrated on a stratch ratio _cale aQ the shaped "
article i~ ~tretched up to 4 times its original dimension. For example, aQ the article is ~tretched ``
4 times it~ original dimension in the X direction (4X), the void~ 70 and 70' uould extent to the point~
74 and 74' re~pective}y.
Figure~ 9 and 10 are actuai photographs of sections of a ~heet accordin8 to thi~ invention which has been fro~en and fractured. The continuou~
matrix, microbeads and voidQ are obvlouA. Figure 11 i~ an actual photo~raph of a section of ~heet material, oriented ln one direction. The scale of the~e photomicrographs is indicated at the top o~
each in micron~ (um).
~ccording to the preQent invention, there are ~
provided shaped articles comprising a continuou~ '~ ! ' -thermoplastic polyester phase having dispersed ~-therein microbeads of cellulose ester which are at ~-lea~t partially bordered by voids. The shaped articles are conveniently in the form of ~heet~ or . . .
. .:" `

- lQ -film, rods or flbers, bottles, wire co~ting~, etc.
The polyester is relatively s~rong and tough, while the cellulose acetate is relatively hard and brittle~
More specifically, the present invention provides shaped articles comprising a continuous thermoplastic polyester phase having dispersed therein microbeads of cellulose ester which are at least partially bordered by voids, the microbeads of cellulose acetate being present in an amount of 10-30~ by ~eight based on the ~eight of polyester, the voids occupying 2-50S by volume of the shaped article, the composition of the shaped article when consisting only of the polyester continuous phase and microbeads of cellulose eQter bordered by voids characterized by havin~ a Kubelka-Munk R value (infinite thickness) of 0.90 to I.O and the following Kubelka-Nunk value~
~hen formed into a 3 mll (~6.2 microns) thick film:
Opacity - ~bout 0.78 to about 1~0 SX - 25 or less KX - about 0.001 to 0.2 Ti - about 0.02 to 1.0 ~hereln the opacity value~ indicate that the article `
is opaque, the SX value~ lndicate a large amount of light scattering throu8h the thickness of the artlcle, the KX value~ indicate a low amount of light absorption through the thickne~ of the article, and the Ti value~ lndicate a lo~ level amount of internal transmittance of the thickness of the article. The R
(infinite thickness) value~ indicate a large amount of li~ht reflectance.
Obviously, the Kubelka-Munk value~ which are dependent on thickness of the article mu~t be ~pecified at a certain thickness. Although the ~haped articies themselves may be very thin, e.g., le~ than 1 mil (25.4 mlcron) or thèy m~y be thlcker, e.~., 20 mils ~508 microns), the ~ubelXa-Munk values, -~

except for R infinity, are specified at 3 mils (76.2 microns) and in the absence of any additives which would effect opt~cal properties. Thus, to determine whether shaped articles have the optical 5 properties called for, the polyester containing microbeads at least partially bordered by voids, without additives, should be formed in a 3 mils thick film for determination of Kubelka-Munk value_. -The shaped articles according to this invention :-10 are useful, for example, when in the $orms of sheets .~-or films, bottles, ribbon~, fibers or rods, wire coatings, etc~ In the absence of additive~ or colorants, they are very white, have a very pleasant :
feel or hand and very receptive to ink from ~ritin8 : .
15 lnstruments, especially conventional ball polnt : :
pen~ In fact, one of the mo~t important u~es contemplated for the present invention is as a :
~ynthetic paper for ~rltlng on or for prlnts ~uch aQ
drauing_~ The qhaped artlcl~ are very reslstant to `. :~
~Qar~ moi~ture, oll, tear~ng, etc~
The polye_tQr ~or copolye~ter~ phaae may be any artlcl~-forming polye~tQr _uch a~ a polysstsr capable ~;
of being ca~t into a fllm or ~heet, ~pun into flbers, axtrud~d into rod_ or extruQion, blow-molded into `
25 contain~r~ such a_ bottles, etc~ The polye_terQ :-~hould have a glaqs tran~ition temperature bstween `.
50C and 150C, pr~ferably 60-100C, Qhould be orientable, and have an I~V~ of at leaQt 0.5$, pr~ferably 0~6 to 0.9. Suitable polyeQterQ include ` : -tho_e produced from atomatic, aliphatic or cycloallphatlc dicarboxylic acid-~ of 4-20 carbon atom~ and aliphatlc or alicyclic glycol3 having from 2-24 carbon atomQ~ Examples of Qultable dlcarboxylic /-acld~ lnclude terephthallc, iQophthalic, phthallc, naphthalene dlcarboxyllc acld, Quccinic, glutarlc, adlpic, azelalc, ~ebaclc, fumaric, maleic, itaconic, .~
.'~ . ` ' 1,4-cyclohexanedicarboxylic, and mixture~ thereof.
Examples of suita~le glycols include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, 1,4-cyclohexanedimethanol diethylene glycol and m~xtures thereof. Such polyesters are well known in the art and may be produced by well-known techniques, e.g~, those described in U.S.
Patents 2,465,319 and 2,901,466. The preferred polyester is polyethylene terephthalate having a T8 of about ~0C. Other suitable polyesters include liquid crystal copolyesters formed by the inclusion `
of a suitable amount of a co-acid component such as stilbene dicarboxylic acid. Examples o~ such liquid crystal copolyesters are those disclosed in U.S.
Patent Nos. 4,420,607, 4,459,402 and 4,468,510. ` "-Blends of polyesters and/or copolyesters are useful in the present invention. Also, small amounts of other polymers such as polyolefins can be tolerated in the continuous matrix.
Suitable cellulo~e acetates are thosQ having an acetyl content of 28 to 44~8~ by wQight, and a viscosity of 0.01-90 seconds~ Such cellulose acetate~ are ~ell ~nown in the art. Small contents of propionyl can usually be tolerated. Also, procosscs for preparing such cellulose acetates are ~cll knoun in the art. Suitable co D ercially available cellulose acetates include the following ~hich are marketed by Eastman Chcmical Product~, Inc.:

O~llulose i it 1 i~ yl ~yl ~elting ~ber ~ erage ~ce~te Poises Content Cont~nt Rangl~ rg, ~l~cular ~ S~conds ~s~l)tSec~? s2_ 2~

a~ 0.0 æ.8 39.5 ~.0 2~260 186 60,000 3 3.01 ~ 1- 39.8 3~5 230~50 180 30,000 C~9~6 6.02.2~ 39~8 3.5 230-250 la2 35,000 ```
1~9~1010.03.80 35~.8 ~.5 230-250 185 ~0,0~0 ``
~39~0 30.0)1.~0 3~.~ 3.5 230-250 ~89 50,0~0 ,~
a~-g20s0.~50.02 32.0 8.- 190-269 bou~ ~ou~
laO-nO 18,000 `` `
~CS ~0 30.4 ~.~ 0.82 2~9-300 1~0 ~02,0~0 ``;

" '`: `
081~ (h~la 1~ ~ D13~3 hts u~ ~olystyr n~ nt ~l~cular ~igt.ts, using ~1 P~a ` `

` `` ` ``
'.
: .
: .....
:~`~.: .. ~
`;'.'''': ,,`
~ ~ :

The microbeads of cellulose esters ran8e in size from 0.1-50 microns, and are present in an amount of 10-30~ by welght based on the weight of the polyester. The microbeads of cellulose acetate have a Tg of at least 20C higher than the Tg of the polyester and are hard compared to the polyester.
The microbeads of cellulose acetate are at least partially bordered by void~. The void space in the shaped articla should occupy 2-~OS, preferably 20-30S, by volume of the shaped article. Dependin8 on the manner in ~hich the shaped articles are made, the voids may completely encircle the microbeada, e.g., a void may be in the shape of a dou~hnut (or flattened doughnut) encircling a microbead, or the voids may only partially border the microbeads, e.g., a pair of voids may border a microbead on oppo~ite `
side-~.
The invention does not require but permits the u~e or addltion of a plurality of organic and inor8anic material~ ~uch as flller~, pigments, ~nti-block~, antl-~tats, plastlclzers, dye~, ~tabili~rs, nucleating agents, etc. The~e materials may be incorporated into the matrix pha~e~, into the di~per~ed phase~, or may exist a~ separate dispersed pha~eQ~
The microvoid~ form on coolin8 without requiring nucleating agent~. During ~tretching the void~
a~-Qume characteri~tic ~hapes from the balanced biaxial orientation of paperlike film~ to the uniaxial orientation of microvoided/Qatin-like fiber~. Balanced microvoid~ are largely circular in the plane of orientation while ~iber microvoid~ are elongated in the dlrection of the fiber axi~. The ~i~e of the microvoid~ and the ultimate physical propertie~ depend upon the de8ree and balance of the orientation, temperature and rate of ~tretching, ",'. ,- ' ,:

crystallization kinetics, the size distribution of the microbeads, and the like.
The shaped articles according to this invention are prepared by (a) forming a mixture of molten polyester and cellulose acetate wherein the cellulose acetate is a multiplicity of microbeads uniformly dispersed throughout the polyester, the polyester being as de~cribed hereinbefore, the cellulo~e acetate being a_ described hereinbefore, (b) forming a shaped article from the mixture by extrusion, ca_ting or molding, (c) orienting the article by stretching to $orm microbeads of cellulo_e acetate uniformly di-qtributed throughout the article and void~
at least partially bordering the microbeads on _ide_ thereof in the directlon, or direction of orientation. `
The mixture m~y be formed by ~ormin8 a melt of the polyester and mixing therein ehe cellulose ::
acetate. The c~llulose acetate may be in the form of -~olid or ~emi-~olid mlcrobeads, or in molten form. ` ` `
Due to the incompatsbility betweQn the polyester and cellulo-Qe acetate, there is no attraction or adheslves between them, allowing ehe cellulose acetate to "bead-up" if molten to form dispersed microbeads upon mixing. If solid or ~emi-solid, the microbeads become uniformly dispersed in the 30 polyester upon mixln8- ~
Wh~n the microbead_ have become uniformly ~ -di-~persed in the polyester, a ~haped article is formed by processe~ ~uch a-q extru~ion, ca~tina or molding. Example~ of extruQion or caqting would be extruding or ca~ting a film or ~heet, and an example of molding would be in~ection or reheat blow-moldin~
''''`

a bottle~ Such forming method_ are well known in the art. If sheets or film material are cast or extruded, it is important that such article be oriented by stretching, at least in one direction.
Methods of unilaterally or bilaterally orienting sheet or film material are well known in the art~
Basically, such methods comprise stretching the sheet or film at least in the machine or longitudinal direction after it is case or extruded an amount of about 1.5-10 (usually 3-4) times its original dimension. Such sheet or film may also be stretched in the transverQe or cross-machinQ direction by apparatus and methods ~ell known in the art, in amounts of generally 1.5-10 (usually 3-4) times the original dimension. Such apparatus and methods are ~ell kno~n in the art and are described in such U.S.
Patent NO-Q. 3,903,234, lncorporated herein by reference.
If the shaped article is in the form o~ a bottle, oriQntation i9 generally biaxial as the bottle i~
atratched in all directions as it is blow-molded.
Such formation of bottles 1~ al~o well known in the art. See, for example, U.S. Patent No. 3,849,530, incorporated herein by reference.
The voids, or ~oid space~, referred to herein surrounding the microbead~ are formed as the ~`
poly~ster continuous matrix is stretched at 8 temperature between the polyester T8 and the cellulose acetate ~8- The microbead~ of cellulose --acetate are relatively hard compared to the polyester continuous matrix. Also, due to the incompatability and immiscibility betwQen the cellulo~e acetate and - --the polyester, the polyester continuou~ m~trix slides over the microbeads a~ it 1~ stretched, cau~ing void~
to be formed at the ~ides in the direction or directions of strQtch, whlch void~ elongate as the ~ -' ', ,: .:""

~ 324477 polyester matrix continues to be stretched. Thus, the final size and sh~pe of the voids depends on the direction(s) and amount of stretching. If stretching is only in one direction, microvoids will form at the 5 sides of the microbead~ in the direction of stretching. If stretching is in two directions (bidirectional stretching), in effect such stretchlng has vector components extendin8 radially from any given position to result in a doughnut-shaped void lo surrounding each microbead.
The preferred preform _tretching operation simultaneously opens ~he microvoids and orients the matrlx material. The final product propertie_ depend :`:
on and can be controlled by stretching time-temperature relationships and on the type and de8ree of stretch. For maximum opacity and texture, the stretching i~ done ~ust above the glas~
tran~ition temperature of the matrix material. When ~tretching 1~ done in tho neighborhood of the higher gla-qQ tran~ition temperature, both phaQe_ ~tretch together and opacity decrea~e~. In the former case, the material~ are pulled apart, a mechanical antl-compatibilization proce~ In the latter ca-qe, they are dra~n together, a mechanical `
compatibilization proce~. Two example_ are high-~peed melt _pinning of fiber-n and melt blowing of fiber~ and filmQ to form non-woven/spun-bonded product~. In Qummary, the scope of thi3 invention include-~ the complete ran8e of forming operationQ
30 ~u~t de~cribed. `~
In general, void formation occur~ independent of, and doe~ not require, crystalline orien~ation of the matrix pha~e. Opaque, microvoided fllms have been made in accordance ~ith the methodQ of thi_ invention u~ing completely amorphous, non-cryQtallizing copolye~ter~ a~ the matrix pha_e. ~ `

Crystallizable/orientable (strain hardening) matrix materi~ls are preferred for some properties like tens~le strength and barrier. On the other hand, amorphol~s matrix materials have special utility in other areas like tear resistance and heat sealability. The specific matrix composition can be tailored to meet many product needs. The complete range $rom crystalline to amorphous matrix materials is part of the invention.
Stretching experiments reveal that increasing the cellulose ester content of the blends reduces the effectiva natural draw ratio relative to that of the matrix material and raises the effective orientation or draw temperature~ When melt casting these films, ~ `
required casting roll temperature increases with cellulose e_ter content. Minimal cooling below the orientation temperature prior to stretching is preferred since the cooled preform state i~ often `
brittle, the brittlene_~ increasing ~ith cellulose e8ter content. Thi_ iQ not a problem in blowing bottles from reheated in~ection-molded preforms.
~ nother important and u~eful property of the~e microvoided -~tructureQ i~ the irreverQible closure of the microvoid~ under the action of direct pressure.
25 ~lthough cell/void closure phenomena are not new, the ~`
film~ of thi~ invention repre~ent an improvement over `
the prior art. Hi8h re~olution, clear light paths are created in these partially opaque, light-diffusing filmQ when the microvoid~ clo~e around the clear, cellulose ester microbead~. These closures can be accompli~hed before or after ~ -heat-~etting and also survive the heat-setting procesQ. The films of thi~ invention are u~eful for recording information Quitable for reading by light Qen~in8 device~ or pro~ecting by tran~mitted light.
In~tant ~lide~ have been made by inkle~s wrlting and typing on these films, mounting in a slide frame, and he~t shrinking. When pro~ected onto a ~creen with a conventional slide pro~ector, precise, bright, white images on a soft gray background are seen. When colors are incorporated into the film~, precise, bright, tinted-white images on soft tinted-gray background are seen. When these films are pressure printed with transparent colors, precise, bright, colored ima8es are created. Use of the compositions -and products of this invention for microvoided recording and pro~ection media are the result of and part of the invention~
The following exa~ples are ~ubmitted for a better understanding of the invention.
15In the examples the specified materials were combined and mixed in a dry state prior to extru~ion. Most of the materials used in these example~ are granules (ground through a 2 millimeter ~creen) ~nd fine powders. This form pQrmits good dry blending without ~eparation durlng proce~lng. In most cases, the mixed material~ were dried under vacuum condition~ ulth nitrogen bleed to carry off the volatiles. Of courqe, when ~ubqtantlal amounts of lo~melting material-~ were u~ed, separate drying was done, folloued by mixing and immediate extrusion. The relative amount~ of the polyester, cellulose ester, and other materlals are indicated by ma~s ratio~; and all percent~ are weight S. During exttu~ion, the materlal~ are melted and mixed a~
viscou~ melts. Shear emulsification of the immiscible melts was enhanced with a mixing ~ction centrally located in the meterlng section of the extruder screw. Residence time was kept small by de~i8n; ~or example, ~crew L/D was 24:1 lKillion 3s 1.25 inch (31.8 mm) extruder] and the dies were 30ined directly to the extruder via small-sized adaptors. The extrudate is quenched to form flat films or sheet, tubular films, rods, fibers, or bottle preforms (injection molding). The required ~ orientation was carried out by conve~tional equipment and methods associated with the specific forming operation.
Example ~
Blends were prepared with a polyester and a cellulose acetate. The polyester is Polyester A and the cellulose ester is cellulose acetate CA-398-30.
Two blends ~80~20) and (90~10) were melt cast to form sheets batween 15 to 20 mils (381 to 508 microns) thick. These sheets were simultaneously stretched 4X
(a multiple of 4) in both directions to form white, paper-like films just over 1 mil (25.4 microns) thick. T~e films of this invention are highly diffuse reflective ov~r the visible spactrum and remain highly reflective in the near W (300 to 400 nanometer wavelengths~ region. Typical films proparties and procQssing conditions are giv~n balow.
Exa~al~ 2 (Control) This example is an example of prior art. It is givan here for direct comparison with Example 1.
Blends ware prep~rad with the same polyester as kxample 1 and inorganic materials. The inorganics are tit~nium dioxide tRutile (trademark) R-100] and ~ `
calcium carbonate t~icrowhite (trademark) 25~. A
(90~10) blend of the polyQster and each of tha inorganics was melt cast to form sheets between 15 to 20 mils (381 to 508 microns~ thick. These sheets were simultaneously stretched 4X in both directions to for w~ite, pl~tic-like ~ilms ~ust over 1 mil (25.4 microns) thick. Typical film propQrties and ~- ;
processin~ conditions are given below.

. .
'`.' ~"' .. .:: .
. . .~,.. ..

1 324~77 ExamPle 3 Blends were prepared with a polyester and a cellulose acetate. The polyester is a blend of Polyester A and Polyester A containing a covalently bound colorant. The cellulose acetate is CA-398-30.
Two (80/20) blends (one containing 0.5~ red moiety and one containing 0.5~ blue moiety) were melt cast -to form sheets 20 mils (508 microns) thick. These sheets uere simultaneously stretched 4X in both directions to form pastel-colored, paper-like films about 1.75 mils (44.5 microns) thicX. Typical film properties and processlng conditions are ~iven belou.
Exam~le 4 Blend~ ~ere prepared with a polyester and a mixed cellulose ester, cellulose acetate propionate.
The polyeater iQ Polyester A and the cellulo~e ester is CAP-482-20. This (90/10) blènd and a (90/10) blend made like Example 1 were melt cast to form sheets 15 mils (381 microns) thick. These ~heets were simultaneously stretched 4X in both directions to form translucent, paper-like films about 1 mil ~25.4 microns) thlck. Typical fllm propertie~ and processlng conditions are 8iven below.
Exam~e 5 Blend~ were prepared with the same polyester and cellulose acetate as Example 1. The specific blends (95/5), (90/10~, (85/15), (80/20~, (75/25), and (70/30) were melt cast to form ~heets 25 mils (635 microns) ehick. Extrusion conditionQ were similar to those of EXample 1. TheQe sheets were simultaneously stretched 3X in both direction~ to form ~hite, paper-like films 3 mils (76.2 microns) thick. The~e sheet~ were also ~lmultaneously stretched 4X in both directions to form white, paper-like films 2 mil~ (50.8 microns) thick.
Typical film optical properties are given below.
'' , ' ExamPle 6 This example shows that light-colored, opaque structures developed when the di_persed phase was colored. The polyester of Example 1 was mixed with a cellulose acetate (CA-320S, containing a covalently bonded coloran~). A (90llO) blend (containing 0.13 red moiety) was melt cast to form sheets 15 mils (381 microns) thick. These sheet_ were stretched as in Example 1 yielding uniformly pa~tel-red, opaque, paper-liXe ~ilms.
ExamDle 7 This example shows that lower ViSCQSity polyesters containing minor amounts of additives yielded products of this invention. A blend was prepared uith a polyester and a cellulo_e acetate.
The polyester is Polyester B and the cellulose acetate is CA-398-30. A (90/10) blend wa_ melt cast to ~orm _heets betueen 15 to 20 mils (381 to 508 micron~) thick~ ~ Brabender 3/4-inch ~l9-mm) laboratory extruder ~lthout a mixing ~crew was used at 110 RPM and 260 C (melt temperature). The_e ~heet~ ~ere _imultaneou~ly stretched 4X in both directions to form ~hite, paper-llke fllm-q 3ust over 1 mil (25~4 micron~) thick~ The effect of the optical bri8htener ua~ ually observed to be enhanced by the highly reflectlve structures of this ~ ```
invention. These filmQ contained vi~lble particles of cellulo-qe acetate resulting from the incomplete shear emulsification on this machine.
Ex~mp~
ThiQ example show_ ehat white, opaque properties developed over a ran8e of stretching conditions. A
(90/10) blend of the _ame materials as Example 1 was melt cast using the equipment of Example 6.
Stretching condition-Q were (2xl), ~2x2), (3xl), (3x2), (3x3), (4xl), (4x2), (4x3) and (4x4).
", :.

Whiteness and opacity were visually evident at all levels of stretching, increasing with balance and degree o$ stretch.
ExamPle 9 This example illustrates that polyesterl polyester blends can be used with cellulose acetates to produce articles of thi~ invention. The specific blends of this example are (65125/10) and ~65/15/20) using Polyester A, Polyester C, and CA-398-30 respectively. Films ~ere made as in Example 1, and the resulting properties were similar. The fllms of thi-~ example, howeverl were more flexible due to the presence of the thermoplastic elastomer in the blend.
Example 10 Blends were prepared with a polyester and 8 cellulose acetata. The polyester is Polyester A and the cellulose acetate is CA-394-~OS. The followin~
blends ~95J5), ~90/10~, ~85/15), and (80/20) were melt extruded and Qimultaneou~qly biaxially oriented on a laboratory blo~n film line. The oriented tubeq had a layflat uidth of 9 to 12 incheQ ~22.9 to 30.5 centimeterQ), and the film thicknesi3 was about 0.5 mil (12.? micron_). Thè~e film~q were whiee, opaque, and had tiQ~ue paper qualitieq. Typical film propertie. and proce~_ing conditionq are given below.
Exa~ple 11 Blendq were prepared with a polyester and a cellulo_e acetate. The polye_ter is a blend of Polyeqter A and PolyeQter A containlng a covalently -~
30 bound colorant. The celluloqe acetate is CA-3g8-30.
Four (80/20) blends were melt extruded and ~imultaneously biaxlally oriented as in Example 10.
Typical film propertie~ and processing conditions are 8iven belo~.

ExamDle 12 A (90/10) blend uas prepared with a higher glass transition polyester, Polyester D, and a cellulose --acetate (CA-394-~0S). This blend was melt extruded 5 at a melt temperature of 2~0 C and simultaneously biaxially oriented at about 140 C as in Example 10~ -The resulting film was uhite, opaque, and - -`
paper-like. The quality was slightly degraded because the polyester uas recycled material. This blend system is especially attractive if high temperature resistant products are being manu~actured.
Exam~le 13 The blends of this example ~ere prepared ~rom a polyester, a polypropylene, and a cellulose ~cetate.
The polyester is Polyester A; the polypropylene homopolymer is PP 4230; and ehe celluloQe acetate i_ C~-394-60S. Three blendQ (70/10/20), (75l5/20), and (~7/3/20) ~ere melt extruded and _imultaneou_ly `biaxially oriented as in Example 10~ White, opaque, 20 paper-like film_ ~erQ made, houever film strength and ``
~quality decreased aQ the level of polypropylene increa-Qed~ , . .' ExamPle 14 ~ (90/10) blend ~a_ prepared with a polyeQter, ~` `
Polye~ter A, and a cellulo_e triacetate CA-436-80S.
Thi~ blend ~aQ melt extruded at a melt temperature of 2~5C and Qimultaneou_ly blaxially oriented aQ in Example 10~ White, opaque, paper-llke filmQ were made, ho~ever the quality of the film waQ de8raded by 30 the pre~ence of _m~ll particleq of incompletely ~ ~;
meltQd cellulo~e triacetate.
Exam~le 15 "
Blendq uere prepared with a polyester, Polyeqter A, a uater-di_per_ible polyeQter, and a cellulo_e acetate (CA-398-30)~ The ~olend waQ melt extruded and `
qimultaneou~ly blaxially oriented a~ in Example 10.
".' The white, opaque~ paper-like films were of good quality, with an enhanced hydrophilic character due to the presence of the hydrophilic polyester~
ExamPle lS
A ~90/10) blend of an amorphous copolyester and a cellulose acetate was prepared. The copolyester was Polyester E, and the cellulose acetate was CA-394-60S. The blend was melt extruded and simultaneously biaxially oriented as in Example 10;
however the white, opaque, paper-liXe films had a faint, yellowish tint, indicating greater thermal degradation~
ExamDle 1~
A (90/10) blend of another copolyester and a lS cellulose acetate was preparcd. The copolyester was Polyester F and the cellulose acetaee was CA-398-30.
The blend uas melt extruded and simultaneously biaxially oriented as in Example 10~ A good quality, ~hite, opaque, paper-like film resulted.
Exam~Le 18 A (90/10) blend was prepared from a polyester, Polyester A, and a lower viscosity cellulo~e acetate tC~-398-3). A second (90/10) blend of this polye~tr ~ith a lo~er ~ acetyl cellulo~e acetate tCA-320S) was also prepared. Both blends were melt extruded and simultanQously biaxially oriented as in Example 10.
Good quality, white, opaque, paper-like films resulted. In addltlon, both blendQ were melt extruded à~ in Exa~ple 10, followed by uniaxial (machine direction) drawing in the second bubble.
Thi-Q procedure was used to create tubular or hollow fiber analogs. Relatively strong, white, opaque, textured-~urface structures containing uniaxially dra~n microvoid~ were observed. Fiber structures 35 were also produced by reheating and hand-drawing ``
strands cut from cast sheets.

.

1 3~4477 ExamPle . 19 Another ~90/10) blend of polyester, Polyester A, and cellulose acetate (CA-398-30) was melt extruded on a New Britain in~ection-molding machine to make standard 55 gram preforms (parisons) for 2-litre oriented polyester beverage bottles. The preforms uere reheated and blown at a manual blowing station to produce uhite, opaque, textured, oriented bottles. The surface of these bottles was noticeably -rough ~hen compared with the films and fibers. This ~as a result of the poor mixing conditions in the in~ection-molding machine, a cyclic operation without :
a mixing scre~. ~
;' `' : .
' ' . . -:, `'` ;~' . ~-. .
`',,. ' ~
',''.... ~
-:-.:.. -.... .
` '" ' ' ,.

:.: , .:, ''` -'''-"'"-' EX~E 1 lYPIC~L C~ST ~ ~lEREt~ FIIJI PROPI~TIES
FOR 8a~20 ~ 90tlO POl.YESlER~OELl.UL06E AOETAIE

~bt~ial tao) polyQster ~ (90) Po)yestQr ~20) ~0 ~10) C1~30 ~lt ~ C 260 262 Scr~ Speed (r~ 50 so , .
C~st ~ lp. C 82 58 Cast ~11 SpC d tfP~ 6~0 ~1~83 ~tersh~in~ -Stretcl~ r~p~,~c 120 110 Fi)~ ess bil) 1~3t (3t~8 l~eronS) l~t~ (29.7 ~icrons) Ir~nt Vise~ Id)~9) 0.590 0.623 lI nsity (g~ee) 1~023 1.903 -" `
~nsile'rield tlO psi~t~* 1.~6.61 tSl.0~6.0) 12.8/12.6 tl#~.~a6.9) ~ IlSile I~k tlO pSi) 10.~ ttl.t~60.3) 23.5~22.t tl6V15O
noll5pt~ U ~61 9Vtt ``
~gcn ~ission 16.0 (6.90~ 9.5~ t3.t6) ( ff~t2~ t~)l ~) ~ lys~s ~S~O 1~):
Sc~tt~ 3.6U
~solpt~o~ ~ 0,00~ 0,0~
~tt~ ~t~) 0.21~ 0.302 ` ` `
R flt~ Rtinf~ 0.966 0.966 ~ t~ 0.~12 O.t22 _9~SC~lS ` ` `

EX~PLE 2 C~ST ~ TENnEoED FII~ PROPRTIES
FOR 9oU10 PC~YESTER~rNORGANIc F~L@~
."

~ateria) (90) Polyester ~ (S0) Polyes~er (10) Rutile R-100 tlO) ~lcro~hite 25 ~e~t ~p~, 'C 263 263 Scre~ Speed (rps~ 50 50 C~st oOll ~p., 'C ~2 50 Cast Roll Sp ed (fF~d - ~terh~in - ~
Str~tc~ ~ p., 'C 110 11~ ~.
Fil~ ~ic~n ss ~il) 1.13 (28~ ~icrons) 1~33 (39.8 ~icrons) tn~tr nt Visc. (dlJg~ 0~563 0~573 ~nsity (g~cc) 1~32 1~323 ~nsile Yi~ld (103 psi)~Pa)* 11.3J12.0 (~7~9~82~) lO.U 11~2 t~.SJ7~2) ~nsile 3re~ ~103 ps~) 19~6~20~3 tl2U 1~0) 16.5J17~7 tll4J122) Elong t~on Co 8re-~ tS~ loaJlao 73~
C~yq~n tr~n9~ss~0n s~n ~3~3) 10~2 (~02) aaib tl~t~rl~lero~

~ub~ un~ ~n~lys~s , :.
~0 1~
Sc tt r~ng SX 2~310 ~115 ~boorpt~on ~X o.aa6x o~aoEx tr ns~tt~no~ Tt~) 0.3ao 0~68 O tlectano~ Rt~n ) 0~93t o.ee6 : .
Cp c~ty 0.~2 0.5gl `` ; `
.; .: , ''. .-.' ', ~ls ''' '~'' .:, `, , :," ' ~ ,. . .- .-, .. ..

E~WPLE 3 FOR ~20 POIYES~VRED POlYESlElVOEIIUlOSE ~CET~TE
~2 POIYESTER~BIUE POIYESTER~OEIIUIOS ~OET~TE

. _ _ _ _ l~bterja) 1~5) Poly~ster A (I5) Polyester ~
( 5) Polyester ~ tQed) ( 5) Poly~ster ~ tBlue) 120) C~39B 30 t20) ~39~30 ~lt T~p., C 260 260 :~
Sc~ Speed trp~ 50 50 c~st Ibll r~., c a2 ~2 C st ~Dll Speed tfF~ 6.0 tl~ e~in) 6.0 (l.~ ~ters~in) Str~tcl~ ~p., 'C l20 l25 Fil~ Thickness (~il) l.78 1~5~2 ~icrons) l.T5 t~.< ~icra~s) Inb ~ nt Visc. (dl~g) 0.6~0 0.672 ~ity ~ec) 0~9 0.~95 `
nsil~ Yi~ld tlO psi)~Pa~* 6.19~6.00 t~2.7~ .9~<.92 t3~.3~33.9) ~ nsil~ ~r~ 10~ psi) 8.10~.75 t55.8~5~.4) 5.78~5.39 ~39.9~3~.1) Elong~t~on So Br~-~ r ~ 50~2 l n 3 Cb~n~n T Nnn~ission 18.~ 2~) 21.8 t8~58) Scc~nil~lOO~n 2~n~ tn~ ` `

~1~ b~l~S~s ~#O ~):
Sc~t ring SX 5.571 6.5~0 ~bsorption ~X 2.332x 2.~0Bx lr~nl~tt nc~ ~t~) 0.003 O.OC0 R~fl~ noe Rtinf3 0.-13 0.~3~ :

_9~1S
..

EX~PtE 4 c~sr ~ TENnERED FII~ PR0PERTIES
FOR sO~lQ POLnESTER~ OE IIU~OSE ~ OE t~TE
~D 90~10 poLyEsnER~ OE IIU~05E ~cEr~rE PR0PI0N~TE

~te ia) (90) Polyester A (90) Polyestcr ~elt te~p., 'C 264 (10) W -JB2-20 Scr~ Speed (~ 50 50 C~st Rol~ t~p., ^C ~9 ~9 ~ -C~st Roll Speed (fpe~ 6.0 (1.83 retersh~in) 6~0 (1~83 cetQrst~in) - `
Str tch tc~p~, C 105 llS
Fil~ thi*nKs (~il) 1~03 (26~2 ~icrons) 0~9~ (23~9 ~icrons) ;
Inb r~nt Visc~ (dl~g~ 0~603 0~665 ~-O~ns~ty (g~cc) 1~192 1.36~ :
T~nsile ~i~ld tl0 psi)~ P~* 13.5~13~ t93~1 n ~5) lS~9~1S~l (111~10 nsns~le Brc~ ~10 psi) ZS~S m ~9 tl~6~1~9) 29~0J29~2 (200t201~ . .
Elor~ tion to ~rr~ 6~X18 103~10~ -Cx~g n Tr~nsn~ss h n 8.01 t3~15) ~.3~ (2.~9) tct~ 10C~n 2~Lbr- t~
~1~ '`" ', ':
t~ta~
s~s tS60 ~:
Sc~tt~r~ng 5X 2~39~ 0.399 l~n~rpt~on ~X o.oC6x 0.006x ~r~nn~tt no~ ) 0.2~2 0.~11 Rrfl~K~ o~ Rt~nO 0.930 0.E~8 .
~ 0.,56 ,,:``, 0.~ '.''~
. : ''~ ` ' s '`, '.'";; '~

E~LE 5 la~Ew~ ~IYSES

PolyesterJ
O~llulose 5tretc~1 Str~tc~ Re~at ~t te ~tios t~p. ~i~ T~icltm!ss ~ lh~unlt Valu s _ l~tio~ ~ x Y) C ~S c) ~ils)nlicr~ns~ 5X l~X T(iL Roo OD~City 99J1 3x3 100 ~5 2.~ 68.6 0.20~ 0.012X 0.822 0.~10 0.233 9~2 3x3 100 ~ 2.a ~ 0.2m O~O~X o~ns 0~30 0.289 95~5 3x3 100 60 2.9 ~3. ~ 0.~6~ 0.0~3X 0~529 0~ 0~545 90flO 3x3 100 ~5 3.2 al.3 2.611 O.O~X O.nl O.gOl 0.79 ~5 3x3 100 ~5 3.~ 9~.0 6.~ 0~0~5X 0.128 O.q33 O.gl~
~20 3x3 ~00 ~5 ~.0 102 ll.ag2 0.013X 0.073 0.95~ 0~958 ~25 3x3 ~00 60 3.<a6.~ 12.126 0~016X 0.0~1 0~950 0.961 ~30 3x3 110 75 5~2 132 19~ 160 O~Ol5X 0~0~5 0~961 0~9~a ~25 3~5x3.5 115 60 2~ 6~6 ~262 0~012X 0~ 0~9~5 0~922 ~OQO 3~5x3~5 115 60 5~0 ln 21.990 0~012X Q~0~0 0~96~ 0~9 ~1 *x~ 110 60 1~6~0~6 0~195 O~Olllt 0~2B 0~19 0.22~
~2 *x~ 110 60 1.6<0.6 0.2~0 O~OllX 0~5 0.~49 0.2~3 ~5 ~ 110 6~ 1~8 ~5~ 0~5 O.OlOX 0.56~ 0.~51 0.~
90/~0 ~ ~0 60 2.1 53.3 2.593 O.OlOX 0.2~ 0.9~ 0.7~2 06n5 *x~ 115 60 2.050.a ~.0~6 0~039X 0.193 0.93~ 0.851 ~20 *x 115 *5 2.~68.6 9~699 O~OllX Q.090 0.95~ 0.943 ~30 *x~ 120 120 s.a l~ 22.63~ O.OlSX 0.03~ 0.96~ 0.9~3 e ~ ~ ~ 3 -- ~ o ,~, -`
~3~s~ ~ ~

;; `;`"

' ' ~ . . . !, . ,` A ,, '.. ; ' ' ,', . ~, i , ' . , : ' .

e ~ t ~ 0~
_ _ ~t~ Y~ , æ^ B

: ~ .
i ~i ~ ~ 8n _ ær ~ O _ ~

8- ~ 0 ~O æ

~ 1 ;5 ~ 5 ¦?~

Polyester A is described as follows:
Reaction Product Of:
Dicarboxylic acid(s) - dimethyl terephthalate or Ester Thereof -Glycol(s) - ethylene glycol I.V. - 0.70 .
Tg - 80C .
Tm - 255C -:
Polyester B iQ described as $ollows~
Reaction Product Of ~
Dicarboxylic acid(s) - dimethyl terephthalate or Ester Thereo~ `"`````
Glycol(s) - ethylene glycol ~ `~
I.V. - 0.64 .
Tg - 80C ;
Tm - 255C :
Polye~ter C i~ described as fol lows:
Reaction Product Of:
Dicarboxylic acid~ - 99.5 mol S 1,4-cyclo- `~
haxanedicarboxylic acid or Estar Thereof - 0.5 mol S trimellatic anhydride `.
Glycol(s) - 91.1 mol S 1,4-cyclo-hexanedimethanol 8.9 mol S poly(tetra- `~ `
methylene ether ~lycol) ~
~.V. - 1.05 `
Tg - below 0C
Tm - 120C ..

;~

.', ~ ' ' Polyester D is described as follows:
Reac~ion Product of:
Dicarboxylic acid(s) - Naphthalene dicarboxylic or Ester Thereof acid Glycol(s) - ethylene glycol I.V. - 0.80 :
Tg - 125C
Tm - 265C
Polyester E is described as ~ollows~
Reaction Product Of: `
Dicarboxylic acid(s) - terephthalic acid or Ester Thereof `:
Glycol(s) - t9 mol ~ ethylene glycol 31 mol ~ 1,4-cyclo-hexanedimethanol I.V~ - 0 75 Tg - 80C
Tm - amorphous Polyestor F 1~ described as follow~:
Reaction Product Of:
Dicarboxylic acid(a) - 75 mol ~ terephthalic or E~ter Thoreof acid 25 mol ~ tren~-4,4'- .:
stilbene dicarboxylic : .
acid Glycol(~) - ethylene glycol I.V. - 0.8 Tg - 95C .
Tm - -215C : :-: `
The cellulo~e acetates, desi8nated a~ "CA" are -`
as dofinod in the table above.
~here ratio~ or part~ are given, e.g., 80/20, ~ -they are part~ by ueight, with the polye~ter weight : `:
35 ~pecifiod fir-~t. ` .
~ ' , ' The following applies to Xubelka-Munk values:
SX is the scattering coefficient of the whole thickness of the article and is determined as follows: :
sx = 1 Ar ctgh a-R - Ar ctgh ~
b b b wherein:
b = (a2~ n Ar ctgh is the inverse hyperbolic cotangent .
a = 1~2 R + Ro~ q RoRg .
Ro is reflectance with black tile behind sheet :
R is reflectance with white tile behind sheet Rg is rQflectanca of a white tile = 0.89 .:
KX is the absorption coefficient of the whole thickness of the article and is detQrmined as follows: `
RX = SX (a-l) ~herein SX and a are as defined above R (infinity) i8 th~ reflectance of an article if ` :
the articlQ ~as so thick that additional thickness ~o~ld not ch~nge it and i8 deterDined as follows:
R (infinity) ~ a - (a~-l)m ~herein a is a8 defined above Ti is the internal light transmittance and is deter ined as follows: .~
Ti ~ l(a-Ro)~ n . ~.
Opacity ~ ~Q ~ :
Rg ,~
~herein Ro and Rg are as de~ined above. ~:
In the above for~ulae, Ro, R and Rg are .
deter ined in a conventional manner using a Diano Natch-$can (trade~ark) II Spectrophotometer tMilton Roy Co.) using a wavelength of 560 nanometers. Also :~
above, X in the formulae SX and KX i8 the thickness '';.
. ~ . .

`` I 324477 of the article. A full description of these terms is found in Colors in "Business, Science and Industry"
3rd Edition, by Deane B. Judd & Gunter Wyszecki, publis~ed by John Wiley & Sons, N.Y. (1975), pages 397-~39.
Glass transition temperatures, Tg and melt temperatures, Tm, are determined using a Perkin-Elmer (trademark) DSC-2 Differential Scanning Calorimeter.
In the examples, physical properties are measured as follows:
Tensile Strength at Yield - ASTN D882 Tensile Strength at Brea~ - ASTM D882 ~longation at Break - ASTM D882 Unless otherwise specified inherent viscosity is measured in a 60~40 parts by weight solution of phenol~tetrachloroethane 25C. and at a concentration of 0.5 gram of polymer in 100 mL of the solvent. -`
Where acids are spacified herein in the formation of tha polyesters or copolyesters, it should ba understood that estar forming derivatives of the acids may ba used rather than the acids themselvas as iq conv~ntional practice. For example, di~ethyl isophthalate ~ay bQ u~ed rather than isophthalic acid.
In tha examples, oxygen per~eability is determined according to ASTM D 3985, in cubic canti~QtQrs permeating a 1 mil (25.4 microns) thick sample, 100 inches squarQ, for a 24-hour period under oxygen partial pressure diffarence of one atmosphere at 30-C. using a NOCON Oxtran ttrademark) 10-50 instru~ent. oxygan per~aability is also given in S.T. (Systems International) units in cubic centi~eters peroeating a 1 cm. thick sample, 1 cm.
square, for 1 ~econd at atmospheric pressure.
Unless otherwise specified, all parts, ratios, percentages, etc. are by weight.
.~, ' , ,:

. .' ` . . ` .: .
.

- ` 1 324477 The invention has been described in detail with particular reference to pre$erred embod~ments thereof, but it will be understood that variations and modifications can be effected within the spirit 5 and sCope of the invention~ .

;". -':
:` .
'"`'

Claims (24)

1. A shaped article characterized by having a continuous polyester phase having dispersed therein microbeads of cellulose acetate which are at least partially bordered by void space, said polyester having an I.V. of at least 0.55 and said cellulose acetate having an acetyl content of 28-44.8% by weight and a viscosity of 0.01-90 seconds and being present in an amount of 10-30% by weight based on the weight of said polyester, said microbeads having a size of 0.1-50 microns, said void space occupying 2-50%
by volume of said shaped article.

2. A shaped article characterized by having a continuous polyester phase having dispersed therein microbeads of cellulose acetate which are at least partially bordered by voids, said polyester having an I.V. of at least 0.55 and said cellulose acetate having an acetyl content of 28-44.8% by weight, a viscosity of 0.01-90 seconds and being present in an amount of 10-30% by weight based on the weight of said polyester, said microbeads having a size of 0.1-50 microns, said void space occupying 2-50%
by volume of said shaped article, the composition of said shaped article when consisting only of said polyester continuous phase and said microbeads at least partially bordered by void space characterized by having a Kubelka-Munk R value (infinite thickness) of 0.90 to 1.0 and the following Kubelka-Munk values when formed into a 3 mil (76.2 micron) thick film:
opacity - 0.78 to 1.0 SX - 25 or less KX - 0.001 to 0.2 T(i) - 0.02 to 1.0 - 39a -

3. A shaped article according to Claim 2 wherein said polyester is poly(ethylene terephthalate) having an I.V. of at least 0.55.

4. A shaped article according to Claim 2 wherein said cellulose acetate has an acetyl content of 28 to 44.8% by wt. and a viscosity of 0.01-90 seconds.

5. A shaped article according to Claim 2 wherein said void spaces completely encircle said microbeads.

6. A shaped article according to Claim 2 wherein said microbeads have an average diameter of 0.1-50 microns.

7. A shaped article according to Claim 2 wherein said void spaces surround said microbeads, said void spaces being oriented such that they lie in generally the same or parallel planes.

8. A shaped article according to Claims 2, 3, 4, 5, 6 or 7 wherein said article is a sheet of 0.10-20 mils (2.54-508 microns) thickness.

9. A shaped article according to Claims 2, 3, 4, 5, 6 or 7 wherein said article is a fiber or rod of 0.5-50 mils (12.7-1270 microns) diameter.

10. A shaped article according to Claims 2, 3, 4, 5.
6 or 7 wherein said article is a tube.

11. A shaped article according to Claims 2, 3, 4, 5, 6 or 7 wherein said article is a bottle.

12. A shaped article according to Claims 2, 3, 4, 5, 6 or 7 wherein said article is a wire coating.

13. A paper-like sheet characterized as having a continuous phase of poly(ethylene terephthalate) having dispersed therein microbeads of cellulose acetate encircled by void space when viewed in a direction perpendicular to the plane of the sheet, (a) said polytethylene terephthalate) having a Tg of 60-100°C and an I.V. of at least 0.55, (b) said cellulose acetate having an acetyl content of about 28to 44.8% by weight, a viscosity of about 0.01-90 seconds, and a Tg of at least 20°C higher than the Tg of said poly(ethylene terephthalate), (c) said microbeads having an average diameter of about 0.1-50 microns and being present in an amount of about 10-30% by weight based on the weight of said poly(ethylene terephthalate), (d) said void space occupying about 2-50% by volume of said sheet, and (e) said sheet when consisting only of said polyester continuous phase and said microbeads at least partially bordered by void space characterized by having a Kubelka-Munk R value (infinite thickness) of about 0.90 to about 1.0 and the following Kubelka-Munk values when formed into a 3 mil (76.2 microns) thick film:
Opacity - about 0.78 to about 1.0 SX - 25 or less KX - about 0.001 to 0.2 T(i) - about 0.02 to 1.0

14. The sheet according to Claim 13 wherein said void spaces completely encircle said microbeads.

15. The sheet according to Claim 13 wherein said void spaces surround said microbeads, said void spaces being oriented such that they lie in generally the same or parallel planes.

16. A fiber or rod characterized as having a continuous phase of poly(ethylene terephthalate) having dispersed therein microbeads of cellulose acetate bounded on the lengthwise sides by void space (a) said poly(ethylene terephthalate) having a Tg of about 60-100°C and an I.V. of at least 0.55, (b) said cellulose acetate having an acetyl content of about 28 to 44.8% by weight, a viscosity of about 0.01-90 seconds, and a Tg of about 20°C higher than the Tg of said poly(ethylene terephthalate), (c) said microbeads having an average diameter of about 0.1-50 microns and accounting for 10-30% by weight of said sheet, (d) said void space occupying about 2-50% by volume of said fiber or rod, and (e) said sheet when consisting only of said polyester continuous phase and said microbeads at least partially bordered by void space characterized by having a Kubelka-Munk R value (infinite thickness) of about 0.90 to about 1.0 and the following Kubelka-Munk values when formed into a 3 mil (76.2 microns) thick film:

Opacity - about 0.78 to about 1.0 SX - 25 or less KX - about 0.001 to 0.2 T(i) - about 0.02 to 1.0

17. The fiber or rod according to claim 16 wherein said void spaces completely encircle said microbeads.

18. The fiber or rod according to Claim 16 wherein said void spaces surround said microbeads, said void spaces being oriented such that they lie in generally the same or concentric circles.

19. The method of forming a shaped article having at least one major surface comprising a continuous phase of polytethylene terephthalate) having dispersed therein microbeads of cellulose acetate at least partially bordered by void space oriented generally flatwise with respect to said major surface of said shaped article, said sheet when consisting only of said polyester continuous phase and said microbeads at least partially bordered by void space characterized by having a Kubelka-Munk R value (infinite thickness) of about 0.90 to about 1.0 and the following Kubelka-Munk values when formed into a 3 mil (76.2 microns) thick film:
Opacity - about 0.78 to about 1.0 SX - 25 or less KX - about 0.001 to 0.2 T(i) - about 0.02 to 1.0 said method comprising (a) forming a mixture of molten polyester and cellulose acetate, wherein the cellulose acetate is a multiplicity of uniformly dispersed microbeads throughout said polyester, said polyester having an I.V. of at least 0.55, said cellulose acetate having an acetyl content of about 28 to 44.8% by weight, a viscosity of about 0.01-90 seconds and a Tg of about 20°C
higher than the Tg of said polyester, (b) forming a shaped article from said mixture by extrusion, casting, or molding, (c) orienting said article by stretching at least in one direction to form microbeads of said cellulose acetate uniformly distributed throughout said article and voids at least partially bordering said microbeads on sides thereof in the direction(s) of orientation.

20. The method according to Claim 19 wherein said shaped article is a sheet, fiber or rod and is oriented by stretching in one direction.

21. The method according to Claim 18 wherein said shaped article is a sheet and is oriented by stretching in two directions.

22. The method according to Claim 19 wherein said shaped article is a bottle and is biaxially oriented by blow-molding.

23. The method according to Claim 19 wherein said polyester is poly(ethylene terephthalate).

24. The method of forming a paper-like sheet comprising a continuous phase of poly(ethylene terephthalate) having dispersed therein microbeads of cellulose acetate encircled by void spaces when viewed in a direction perpendicular to the plane of the sheet, said sheet when consisting only of said polyester continuous phase and said microbeads at least partially bordered by void space characterized by having a Kubelka-Munk R value (infinite thickness) of about 0.90 to about 1.0 and the following Kubelka-Munk values when formed into a 3 mil (76.2 microns) thick film:

Opacity - about 0.78 to about 1.0 SX - 25 or less KX - about 0.001 to 0.2 T(i) - about 0.02 to 1.0 said method comprising (a) forming a molten mixture of poly(ethylene terephthalate) and cellulose acetate, wherein the cellulose acetate is uniformly dispersed throughout said poly(ethylene terephthalate); said poly(ethylene terephthalate) having a Tg of about 80°C, and an I.V. of at least 0.55, said cellulose acetate having an acetyl content of about 28 to 44.8% by weight, a viscosity of about 0.01-90 seconds and a Tg of about 20°C higher than the Tg of said poly(ethylene terephthalate), (b) casting a film of said mixture, and (c) orienting said sheet by stretching to form microbeads of said cellulose acetate uniformly distributed throughout said sheet and encircled by doughnut-shaped voids lying in planes generally parallel to the surfaces of said sheet.