CA1188345A

CA1188345A - Sealant strip

Info

Publication number: CA1188345A
Application number: CA000411048A
Authority: CA
Inventors: Arthur Hauptman
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1981-09-21
Filing date: 1982-09-09
Publication date: 1985-06-04
Also published as: BE894455A; US4356676A; DE3234808A1; GB2106559A; GB2106559B; FR2513342A1; JPH0222783B2; JPS58132072A; FR2513342B1

Abstract

ABSTRACT
A sealant strip is provided having a soft, resilient synthetic foamed resin core, preferably having a pressure sensitive adhesive coating on at least one of two of the opposed sides of the core and thin preferably silicone rubber sealing layers cured in situ on the two remaining surfaces of the core. The strip is adapted for adhesive attachment to and compression between structural members, with the core supporting the edges of the sealing layers in contact with the opposed surfaces of the structural elements between which the strip has been compressed.

Description

TECHNICAL FIELD
This invention relates to a flexible resilient sealant strip for use between structural and non-structural elements to form an effective air and moisture barrier.
BACKGROUND ART
5 Prior Art Statement The following publications are representative of the most relevant prior art known to the Applicant at the time of filing the application:
United States Patents

2,232,094 August 4, 1942 D. F. Dreher 2,395,668 February 26, 1946 W. Kellgren et al 2,565,509 August 28, 1951 R. C. Marcin 2,882,183 April 14, 1959 H. M. Bond et al 4,169,184 September 25, 1979 J. Pufahl 4,199,645 April 2~, i980 Gunter Schwarz 4,232,489 November 11, 1980 E.J. Corvington et al Various types of flexible sealant strips have been proposed that carry a pressure sensitive adhesive for attaching the strip to a surface to be protected. One such 20 known weather resistant 5trip adapted for use between a base and decorative layer attached to an automotive body for example is shown in U.S. Patent 4,169,184 wherein a body of open celled, high density, flexible urethane foam that is impregnated with a vulcani~ed polychloroprene elastomer to form a deformable base material is described, the base being coated on opposite sides with a pressure sensitive adhesiven The tape or strip may be dispensed in a roll form and is made to have a significant inherent resilience and flexibility yet is described as including an ability to withstand elongation.
30 The tape is prepared to be non-absorbent and solvent ~,~
~, resistant ~or use in areas where gasoline, oils and greases might cause problems.
U.S. Patent 4,199,645 also shows a laminated adhesive strip having an elastic carrier layer coated on 5 opposed sides with adhesive layers having different characteristics for adhesion to different types of surfaces.
A basic form of a flexible and deformable strip coated on both sides with a pressure sensitive adhesive is illustrated in ~.S. Patent 2r292~024O This teaching provides lO an adhesive mounting strip for use between objects having irregular or undulating surfaces to provide a more uniform adhesive bonding action.
The use of release strips in combination with rolled up tapes having pressure sensitive adhesive on both 15 sides thereof is known and typical tapes of this type are illustrated in U.S. Patents 2,395,668, 2,565t509 and 4,169,184 mentioned above.
U.S. Patent 2,882,183 describes a silicone tape backing having a single layer of a silicone adhesive on one 20 side to form an electrical insulation that can be wrapped around an exposed electrical connection and then heated after it is in place to weld the laye`rs of tape together to produce a sealed electrical covering.
U.S. Patent 4,232,48~ shows a flat strip of plastic 25 foam forminq a core for a tape with a pressure sensitive adhesive on one side for attaching the tape to a bow of a ~reenhouse enclosure for example, the tape having a silicone coated kraft paper adhered to its other side that forms a relatively friction free support surface for a sheet of 30 plastic material laid on the exposed silicone impregnated paper material.
Thus the known flexible tapes show various types of adhesive strip structures adapted for insertion between elements to be associated together. However, none of these 35prior art teachings i~ directed to the problem of providing an effective substitute for a caulked seal between structural elements. It is the purpose of this invention to provide a sealant strip having various features of the known prior art ~:~3~

combined together in a novel construction to satisfy the need for a flexible sealant strip adapted to mounting at the edges of abutting structural members to produce weather or moisture and air flow resistant seals alonq such joints to provide an 5 effective seal.
None of the above described tapes is very well adapted to provide a substitute for a caulking such as is extruded conventionally into a joint to effect a waterproof seal for example, such caulking is usually applied after a 10 structure has been erected. In this instance it is essential that the ~oint to be sealed be thoroughly cleaned before the caulking is forced into the joint and the sealant must be carefully applied throu~h an extrusion nozzle moved along the joint. The proper auantity of sealant must be extruded to 15 fill the ~oint and it must be applied in such a manner as to not interfere with the proper expansion and contraction of the seal in a manner to avoid breakinq the seal. It is di~ficult to deliver the flowing sealant into the joint without some possibility of there being air holes, skips, and 20 uneven application of the sealant in a manner to produce a uniform concave surface shape when it solidifies in place.
In fact, the application of the usual caulkin~ sealant in a joint after the structural parl:s have been assembled is so dependent on the skill of the operator that it should be 25 considered more of an art than a science.
BRIEF DESCRIPTION OF THE INVENTION
._ It is the p~rpose of this invention to provide a sealant strip that may be laid up with the building elements forming a structure as they are being assembled to eliminate 30 the need for caulking the joint between the elements after the assembly has been completed. In following ~his invention a flexible and resilient tape is trapped between these abutting elements to fill the joint and seal it.
It is the object of this invention to provide a 35 resilient and elastic laminated sealant strip for use in forming such sealed joints between two structural elements which sealant strip may be installed in a manner to provide a barrier to moisture and air flow. The core of the strip is

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-4 made of a foamed synthetic resin that has a relatively low densit~ and low internal strength but which is resilient and elastic. Preferably the core has a rectangular crossection and has two of its opposed si~es coated with a layer of

5 Pressure sensitive adhesive. The remaining two sides are each coated with an integral cured thin layer of a flexible and resilient silicone rubber.
The sealant strip is adapted to be attached with the pressure sensitive adhesive to one elernent of a joint and 10 the other abutting structural element is then moved in~o its assembled position in engagement with the other pressure sensitive adhesive coated on the other side of the strip.
When the strip has thus been adhesively attached to both the elements at their junction, the silicone coatings which cover 15 the other faces of the rectanqular strip are facing the opposite exposed sides of the joint and the resilient and elastic core will hold the edges of each of these silicone surfaces pressed gentl~ against the surfaces of the two structural ele~ents to seal the joint. The si]icone rubber 20 coatings on the sides are impervious to moisture and air whereby an effective barrier seal is formed by com~ressing the sealant strip between the ed~es of the structural elements to be sealed.
In some instances it may be desirable to add a 25 uniformly extruded sealing fillet at the edges of the silicone layer where the exposed layer is pressed against the structural element. Such a fillet along each edge of the exposed silicone layer can be used to more assuredly bond the sealant strip to both structural elements to ensure a perfect 30 seal along the entire length of the joint.
BRIEF DESCRIPTION OF THE DRAWING
__.
Figure 1 is side elevation showing the sealant strip as it is dispensed for use;
Figure 2 is a crossectional view of one layer of 35 the strip taken on line 2-2 of Figure l;
Figure 3 is a crossectional view of a joint formed between structural elements, making use of this sealant strip.

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DETAILED DESCRIPTION OF T~E_ INVENTION
The flexible strip of this invention is preferably adapted to be packaged for distribution from ~he factory in a roll form as shown in Fiq~ 1. The strip includes a foam core 5 10 having a rectangular crossection and is made of a foamed synthetic resin selected from any of the conventionally known foamable open cell9 flexible resilient synthetic resins such as a polyester-urethane foam. Other foamed core compositions may be used such as other resilient polymeric materials 10 includin9 p~lyvinyl chloride, polyisobutylene, polyethers, polyesters, silicone rubbers, fluorocarbon rubbers, butyl rubber, and polychloroprene.
The core is designed ~o be resilient and elastic to conform easily to the surface agaînst which it is pressed as 15 it is applie~ and for this purpose a foamed resin having a low internal stren~th is preferred. The core preferably is selected to have a density within the range of about one pound per cubic fo~t of the foamed ~ore materialO
Two opposed sides of the core are each coated 20 respe~tively with thin layers ~r coatin~s 12 and 14 of a known pressure sensitive adhesive, preferably a tacky adhesive, such as an acrylic re~in like that disclosed in ~.S. Patent 4,169,184, having the ability to tenaciously adhere to a wide variety of surfacesO Other suitable 25 adhesives are those based on plastomerics like acrylic, polyvinylether~neoprene, styrene-butadiene 9 acrylonitrile, urethane, silicone, polyisobutylene and the like. These pressure sensitive adhesive l~yers cover essentially the entire surface of each of the opposed surfaces of the core 10 30 for maximum engaqement o the strip with the structure with which it is to be associated and the entire length of one ~f the adhesive layers such as layer 12 of the roll is covered with a known type of cured sili~one coated release tape 16 so that the roll may be easily unwound and the release tape i~
35-removed to expose the adhesive layer when the strip is to be applied to the elements forming the joint of a structure which is to be sealed~ The adhesive may not be necessary in some applications ~ut is certainly an aid to utilizing the sealant strip.
The remaining two sides of the core 10 are each entirely coated with an impervious layer of a high performa~ce cured coating to form thin resilient sealing 5 layers such as 18 and 20. These cured coatings produce water and air resistant seals over the exposed faces of the core of the sealant strip when it is in use as will be described more fully belowO Preferably these coating are formed of a thin flexible, resilient silicone rubber material that can be l0 easily deformed with the core material when the core is pressed and deformed between the two surfaces to be sealed to preclude the flow of moisture or air through the foamed core that fills the space between the two elements of the structure. Other coating polymers include, among others, 15 polyurethane, flexible epoxy and the like, as well as thermoplastic films like polyvinyl chloride.
The sealant strip is suggested for use in any joint beinq constructed by placin~ two matin~ parts together where a perceptible ~ap inherently is produced by the mating of the 20 structural parts~ The sealant strip is selected to have a width to fill the gap between the parts to be sealed and preferably should be compressed to a thickness of about 75%
of it~ original thickness. Referring to Figure 3 the strip is shown positioned between two logs 22 and 24 forming the 25 wall of a building with the strip compressed in the gap 26 which has been illustrated in the drawings in an exaggerated degree. The sealant strip is positioned along the length of the joint and is compressed somewhat all alo~g the length of the ~oint on an average of as much as 25% of its thickness 30 whereby the core 10 resiliently presses the edges of the exposed sealinq surfaces 18 and 20 tightly against the surfaces of the logs between which the strip is positioned.
Preferably the sealant strip installed in the gap of a ioint between two structural elements can be more 35 assuredly sealed by applying two small uniformly extruded fillet heads 28 and 30 length-wise along the edges of the exposed sealin~ layer 18 as shown in Figure 3. The fillet material is selected to be one that bonds to the surface of ~ 7--the 6tructural elements 22 and 24 and is also ~ompatible with and b~nds to the cured sealing layer 18. Usually a silicone fillet material will be found most useful for bonding to most surfaces and the cured silicone sealing layer as is used in 5 the preferred construction of this sealant strip. However, other caulking materials are opera~le as well, such as butyl rubber " polysul f ide or phenol ic based materials.
As will be underst~od frc>m ~che above~ this strip suggests itself for use in effectively we~ther sealing a lO joint between logs in a structure where exact tolerances cannot always be ea~ily maintained~ ~150 for example in the installation of curtain walls in a building~ this sealant strip will be found most useful.
It is apparen~ that the sealant strip described 15 above may be utilized to completely seal many joints that occur in normal buildin~ s~ructures that have heretofore required the application of caulking to seal the joint after the structure has been completed. The disadvanta~es inherent in the application of an extruded caulkin~ into a joint are 20 completely eliminated when the herein disclosed sealant strip is used in such joints. The cure~ sealing layers 18 and 20 preclude the flow of air or m~isture into the joint and thus form a most effective seal especially as in the pre~erred form when fillets which may be easily extruded, are used. It is 25 to be noted that when such fillets are laid over the joint between the structural elements and coatings 18 and 20, the fillets need be placed merely in contact with both surfaces to which ~he fillets are bonded and need n~t be made to fill the space in a joint having a variable thickness as when 30 extruding caulking into a joint.
The sealing layers 18 and 20 with or witho~t the fillets at their edges always provide a uniformly dispos*d ~ealing bridge between the structural elements and may be colored to provide an artistic seam if desired. This more 35 uniform appearance at the seam is realized by the simple placement of the sealant strip in the joint as the ~tru~ture is assembled, no special ~kill be~n~ reyuired to assure a perfect alignment and shape of the joint as compared with 83~5 the craftsmanship re~uired for properly extruding a caulked seal in a joint.
While the invention has been described in terms of a sealant strip having a rectangular cross section, it is to 5 be understood that it may ~ake on a different cross section depending on its specific usel e.g. a U-shaped sealant strip could be used to bed a curtain wall; or the cross-section could be I shaped, or the like.
The above describes the preferred form of my 10 invention but it is suggested that modifications thereof may occur to those skilled in the art that will fall within the scope of the claims which follow.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A strip adapted to be used for sealing a joint between two abutting structural elements comprising a core of foamed synthetic resin that is resilient and elastic, and which includes on two opposite sides thereof, a high performance cured flexible coating that is impervious to water and air, and at least one of remaining two sides being coated with a pressure sensitive adhesive layer.

2. A strip according to Claim 1 wherein said foamed synthetic resin is one selected from the group consisting of polyurethane, polyvinyl chloride, polystyrene, polyisobutylene, polyethers, polyesters, silicone rubber, fluorocarbon rubbers, butyl rubber, and polychloroprene.

3. A strip according to Claim 2 wherein said high performance cured flexible coating is one selected from the group consisting of silicone rubber and polyurethane.

4. A strip according to Claim 1 wherein said core has a generally rectangular crossection and a layer of a pressure sensitive adhesive carried on at least one side of the core; and wherein two of the remaining sides have a thin, resilient layer in the form of a high performance cured coating thereon that is impervious to water and air.

5. A strip as in Claim 1 wherein said layer of a high performance cured coating is a silicon rubber resin.

6. A strip as in Claim 1 rolled into a coil for storage until used wherein a release tape is carried on one of said pressure sensitive layers and said strip is wound into a roll with said release liner separating the coils of the roll to permit easy unrolling of the rolled strip for applying the strip to one of said structural elements, and wherein said liner may be left on said one surface of the unrolled strip until the other structural element is brought into engagement with said strip so that a sealed joint can be completed.

7. A strip as in Claim 1 wherein said core has low internal strength.

8. A strip as in Claim 1 wherein said core has a low density in the range of one pound per cubic foot.

9. A strip as in Claim 1 wherein said core has a thickness of up to three fourths of an inch between said sides that are covered with the pressure sensitive adhesive.

10. A sealant strip adapted to be used for sealing a joint between two abutting structural elements comprising a core of foamed resilient polyurethane having a rectangular cross section, two opposite sides of said sealant strip being coated with a pressure sensitive adhesive, and the remaining two sides of the sealant strip having a thin layer of a cured silicone rubber thereon.