CA1144009A

CA1144009A - Pressure sensitive composite article, method, and substrate/article combination

Info

Publication number: CA1144009A
Application number: CA000303804A
Authority: CA
Inventors: Gregory M. Sheyon
Original assignee: Stauffer Chemical Co
Current assignee: Stauffer Chemical Co
Priority date: 1977-07-28
Filing date: 1978-05-19
Publication date: 1983-04-05
Also published as: GB1602233A; BR7804091A; NL7806262A; AR221594A1; IL54748A; JPS5425982A; FR2398603B1; IT7850476A0; AU3632778A; AU519508B2; SE7805814L; DD137554A5; YU183178A; IL54748A0; NO782577L; FR2398603A1; DE2832343A1

Abstract

ABSTRACT OF THE DISCLOSURE

A pressure sensitive composite article which is useful, for example, as an exterior roofing material for a vehicle, is disclosed. It comprises a plastic film which is attached to a backing material which has a substantially continuous coating of pressure sensitive adhesive on its opposite side thereof. A re-lease liner is preferably attached to the adhesive layer on the opposed side to the backing material. The invention also includes a method of affixing such a composite article to a desired sub-strate, e.g., a vehicle, by application of pressure alone, as well as the resulting substrate/article combination.

Description

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CIP of C-5066 Background of the Invention Field of the Invention The present invention is a pressure sensitive,plastic film/
flexible backing composite article useful as, for example, a vehicle roof ma~erial, its method of application to a desired sub-strate, and the resulting substrate/article combination.
Description of the Prior Art Plastic film, flexible backing composite articles suitable, for example, as a roofing material on vehicles, e.g., automobiles, are known products. Such composite materials have other uses, for example as padded vinyl wallcoverings,liningmaterials for automo-bile trunks, etc., but will be described herein in connection with their primary commercial use as a roofing material for motor vehicles, such as automobiles.
Such composite articles when used as vehicle roof materials have been conventionally sold to the vehicle manufacturers without a layer of adhesive and the manufacturers would spray the exposed side of the backing material with a solution of a contact adhesive in the vehicle manufacturing plant and then affix the sprayed com-posite article to the vehicle substrate which had also been covered with the same adhesive (see U.S. Patent No. 3,935,353 to R. G. Doerfling et al., Col. 1, lines 31~45). Contact adhesives are adhesives which must be applied to both surfaces that are to be bonded together. They cannot be considered to be "pressure sensitive" adhesives as that term is employed herein. Such a technique has a number of serious disadvantages. Spraying of solvent based adhesives in the vehicle plant can give rise to potentially serious environmental/safety/health problems. The technique is rather time consuming and involves the use of greater amounts of manpower than desired. The spraying of adhesive onto - ~.4~9 CIP of C-5066 the backing can also result in a non-uniform and discontinuous ad-hesive coverage of the backing leading to formation of voids be-tween the backing and vehicle roof which can permit corrosion problems when the finished vehicle is placed in actual service.
An alternative to this conventional procedure is described in U.S. Patent Nos. 3,8~6,200 and 3,935,353 to R. G. Doerfling et al. In these patents a plastic film/flexible backing product con-taining a layer of a non-pressure sensitive, heat activatable ad-hesive is proposed. Such a product, although overcoming some of the shortcomings of conventional in-plant spraying techniques also has certain drawbacks. One of the most serious is the need for heating means in the automobile assembly area to heat the adhesive to its heat-activatable temperature at which tackification occurs.
This may require an additional undesirable capital investment for the vehicle manufacturer. In addition, plastic film materiaI in such a technique must be preformed in a press with heat prior to application in order to insure the proper fit.

Summary of the Invention . .
The present invention is a preSsure sensitive composite article suitable for use, e.g., as a roofing material on vehicles, which, when used to provide such a roofing material, overcomes the shortcomings noted above for solvent sprayed, contact adhesive con-structions and constructions containing a heat activatable adhesive.
It comprises a plastic film which is attached to a backing material which has a substantially continuous and uniform coating of a pres-sure sensitive adhesive on the side thereof which is remote from the plastic film and, in a preferred embodiment, which also has the exposed surface of the adhesive layer covered with a release liner to protect this layer from contamination. The present invention ( : ~

CIP of C-5066 ~- also includes a method of affixing such a laminate to a desired substrate, e.g., a vehicle, by application of pressure only, and it also includes the resulting substrate/composite article combin-ation.
The composite article of the present invention, when used ` as a vehicle roof material, has the following major advantages over the prior art use ofsprayed solvent adhesives elimination of ~; the potential environmental/safety/health hazards involved with spraying potentially toxic solvents in the workplace; a reduction in the time and manpower needed to apply the article to the vehi-cle; and a greater degree of protection from corrosion in the composite article/vehicle combination due to the presence of a substantially continuous and uniform layer of adhesive in the article of the present invention to provide a substantially continuous and uniform surface for contact with the substrate.
The article of the present invention has the following major advantages, when used as a vehicle roof material, over the `~ use of a heat activatable adhesive such as shown in U.S. Patent Nos. 3,846,200 and 3,935,353 to R. G. Doerfling et al.: heating of the article after its application to a vehicle is not necessary to affect an adhesive bond between the article and the vehicle -~ substrate; and preforming the article in a heated press is not needed~

Description of the Drawings ;~ .
:
~; The Drawings which form a portion of this specification may be consulted to further understand the composite article of the present invention wherein:
Figure 1 is an enlarged, cross-sectional view of the clos-est known prior art article showing the discontinuous layer 6 of ., ~
. . . . . . ... . . . . .. . .

CIP of C-5066 non-pressure sensitive,contact adhesive after the adhesive has been sprayed onto the backing 3 in a vehicle assembly plant; and Figure 2 is an enlarged, cross-sectional view of a pre-ferred embodiment of the present invention as release liner 8 is being removed from the substantially continuous and uniform layer of pressure sensitive adhesive 7 preparatory to affixing the com-posite article to a desired substrate, e.g., a vehicle roof.

r I Descri~tion of Preferred Embodiments of the Invention , s_ _ _ _ The composite article of the present invention comprises some elements which are old, namely, plastic film 1 as well as ` flexible backing 3, which is attached to film 1. A suitable ad-hesive 2, e.g., a plastisol adhesive, can be used to attach plas-tic film 1 to backing 3, if desired, and this adhesive layer is also sometimes used in film l/backing 3 articles known to the prior art. Any person of ordinary skill in the art would be able to select appropriate materials for making such a film/backing sub-combination ~optionally joined with adhesive) from the description which follows.
The plastic film 1 may be formed of any thermoplastic or thermosetting synthetic polymer which, preferably, is resistant to weathering and ultraviolet light so as to provide a long, use-ful life for the composite article should it be intended to be affixed to a vehicle and used as a roofing material. Representa-tive plastic film materials include the ~;inyl and vinylidene, acrylic, urethane, polyester, fluorocarbon, and polyolefin poly-mers and compatible blends thereof. Vinyl chloride polymers are l.i economically preferred. Preferred vinyl chloride polymers may , ;

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CIP of C-5066 be any of the conventional polyvinyl chloride resins that have been hithertoused in such applications in formulation with any desired and suitable plasticizers, fillers, stabilizers, pigments, fungicides, process aids, and the like. If desired, internally plasticized vinyl chloride polymers may be used instead of the combination of conventional vinyl chloride polymers and external plasticizers. The thickness of this plastic film will generally range from about 5 mils (0.13 mm.) to about 25 mils (0.7 mm.) al-though thinner as well as thicker films can be used, if desired.
The film can be formed by any fabrication technique known to the art and is generally embossed with a suitable decorative pattern.
It may be covered with a thin protective polymeric topcoat (not shown), such as a urethane, acrylic or vinyl polymer or compatible blends thereof, to protect it from degradation due to mechanical, chemical and environmental factors.
The film 1 is attached to a backing which is broadly in-:, .
dicated by reference numeral 3 in the Figures. The attachment of :, backing 3 to film 1 can be made by means of a thin adhesive layer

2 or the film 1 can be directly attached to the backing 3 (e.g.~
by extrusion or calendering of hot plastic film 1 onto the back-ing 3) so that the attachment is made without the need for an intermediate adhesive layer.
The backing 3 can be selected from a wide variety of back-ing materials, such as non-woven, woven, knit, or composite mater-lals (non-woven/foam combinations, non-woven/knit combinations, non-woven/woven/knit combinations, etc.) to provide a sufficient-ly thick layer which will aid in camouflaging any surface irreg-ularities that may exist on the substrate, e.g., vehicle roof, when the composite article is in position on the substrate. The term "backing" as used herein is to be construed as relating to ~ such backing materials which are well known in the art of making ,.

CIP of C-5066 film/backing composite articles which are useful, for example, as exterior roofing materials for vehicles. Generally the weight of the backing material will range from about 2 to about 20 oz/yd2 , (68-680 gm./m2) and its density from about 2 to about 20 lbs/ft3 (32-320 kg/m3). The thickness of the backing and film composite will generally range from about 20 to about 200 mlls (0.5 - 5.1 mm.), preferably from about 55 mils (1.4 mm.) to about 85 mils (2.2 mm.).
A preferred backing material for reasons of improved tailorability of the finished product are the commercially avail-able backings of a non-woven fabrlc of synthetic fibers which have ~ been needle punched into a thin layer of foam. Some preferred ex-; amples of fibers which can be used in such a backing include: poly-propylene, rayon, polyester, acrylonitrile, nylon, polyphenylene ~5 sulfide, and mixtures thereof. Suitable foam materials which can be used include urethane and polyvinyl chloride foams. The denier ~; of such fibers in this type of backing can range from about 1 to about 20. "Denier" is defined as a unit of fineness equal to the fineness of a yarn weighing one gram for each 9000 meters. The "
foam in such a backing can have a thickness of from about 10 mils (0.25 mm.~ to about 150 mils (2.5 mm.) The backing 3 is preferably made water repellent by treat-ment with an effective amount of at least one water repellent agent when the composite article of the present invention is to have an ; , 25 ~ exterior use, e.g., as a vehicle roof material. Fluorocarbon , . . .
emulsions, which are available under the trademarks "Zepel" (from ; E. I. DuPont de Nemours Co.) or "Scotchguard" (from 3M Co.), are representative types of materials which can be used to confer such water repellency. In order to treat the selected type of backing material, it can, for example, be placed in a fluorocarbon bath, dried, and the resulting product can be cured. The product that results from either this or alternative treating procedures will CIP of C-5066 resist being wetted by water, oil and other contaminants. Further information on how backing 3 might be rendered water repellent can be ascertained from "Waterproofing and Water Repellency", Kirk~
Othmer Encyclopedia of Chemical Technology, 2nd Edition, Vol. 22, pp. 135-156 (1970).
If desired, one or more corrosion inhibitors can be used to treat the backing 3,if the article is to have exterior uses,in order to confer or enhance corrosion protection on the article/
substrate combination. The corrosion inhibitor can be any compat-ibleinhibitor and can be applied in conjunction with the afore-mentioned water repellent agent. For example, when a fluorocarbon bath treatment is employed, suchknown corrosion inhibitors as the nitrites, phosphates, chromates and sulfates might be present in the bath to act as a corrosion inhibitor when the article is sub-jected to exterior use for the final article/substrate combination that will be produced. One corrosion inhibitor which is preferred for economic reasons is sodium nitrite. Further information on how the backing 3 might be treated to render the article/substrate combination corrosion resistant can be ascertained from "Corrosion Inhibitors", Kirk-Othmer Encyclopedia of Chemical Technology, 2nd Edition, Vol. 6, pp. 317-346 (1965).
The composite article of film 1 and backing 3 which is known to the prior art can be formed by a number of well-known processes such as direct calender lamination or extrusion coating, post lamination or casting.
Direct calender lamination or extrusion coating produce a composite article without the use of adhesive layer 2. The plastic film 1 acts as the adhesive because it is brought in contact with the backing 3 shortly after formation while the film 1 is still ~30 hot and sticky.

CIP of C-5066 Post lamination is another well known method and differs from the extrusion coating or direct calender lamination tech-niques in that the plastic film 1 is not usually formed just prior to the bonding step and an adhesive layer 2 is applied directly by known coating techniques (gravure cylinder, knife, roller, reverse roller, etc.) to the film before the film is contacted with the backing 3. A roll of preformed film is generally the source of the film, and a thin layer of adhesive is applied to the side of the film which is to be bonded to the backing. The adhesive is applied by a suitable means usually in an amount in the range of from about 1 to about 5 oz./yd. 2 (34 to 170 g/m2) depending upon the adhesive. The coated film then is contacted with the backing to form the composite article known to the prior art.
Adhesives suitable for use in the post lamination technique are well known in the art. Some examples include plastisol, epoxy, acrylic, and urethane adhesives~ Plastisols are one of the best known materials. These are dispersions of finely divided polymer-ic materials in nonvolatile organic liquids and low melting solids, generally referred to as plasticizers. Suitable plasticizers in-clude phthalate, adipate and sebaccate esters and polyols such as ethylene glycol and its derivatives. A typical plastisol composi-tion is 50 parts polymeric material and 50 parts plasticizer, forming a paste which gels, and fuses when heated to about 300F.
as a result of solvation of the resin particles by the plasticizer.
If a volatile solvent is included in the plastisol, then the ad-hesive generally is referred to as an organosol which also is suit-able for use in the invention.
In order to form the final pressure sensitive, composite article of the present invention, the exposed side of backing 3 is coated with a substantially continuous layer 7 of a suitable tacky, pressure sensitive adhesive. Pressure sensitive adhesives are a well know~ class of adhesives and develop maximum adhesive bondingwith the application of pressure alone. Preferred adhesives of this class are those which exhibit good adhesion and, when the article is to be used in exterior applications, outdoor durability.
.S Self crosslinking thermosetting acrylic pressure sensitive adhes-ives are one preferred class which can be used in the forming of the laminate of the present invention. Illustrative U.S. patents describing adhesives of this type are U.S. Patent Nos. 3,269,994,

3,579,49n and 4~005~247O Preferred formulations are available under the trademarks "Aroset 1085'1 ~Ashland Chemical Company), "Bostik 7525" (~SM Corp.) and "D~-7025 (Daubert Chemical Co.).
These adhesives have, moreover, shown to have especially good compatibility to backings containing the water repellent and/or corrosion inhibitor agents described above. The thickness of the adhesive layer in the composite article of the present in-vention can range from about 0.5 mil (0.01 mm.) to about 10 mils (0.25 mm.). The layer is deposited on backing 3 so that it forms , .
a substantially continuous coating which is also substantially free of voids, channels and the like. The presenceof such a layer affords a barrier between the substrate and the atmosphere to ''!,~ moisture and other environmental factors which are prone to cause corrosion when the article is used in exterior applications in the substrate/article combination.
The composite article of the present invention can find utility without the presence of release liner 8, for example, if it is used shortly after application of the adhesive layer, and care is taken to avoid contamination of the exposed surface of the .,;
adhesive layer 7 with foreign matter. If this embodiment of the invention is desired, the adhesive in the form of a viscous fluid can be cast onto the backing 3 and dried by the application of heat.
In most end uses however, the composite article will be manufac-tured with a suitable release liner 8 by a manufacturer,and the product will be sent to a customer for use.

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CIP of C-5066 The release liner 8 may be any of the release liners known to persons of ordinary skill in the art of making pressure sensi-tive products including removable, water soluble protective coat-ings, and the like. One preferred liner material is silicone coated release paper having a thickness of from about 2 mils (0.05 mm.) to about 10 mils (0.25 mm.) Polyolefinic (e.g. ethyl-ene), ethylene/vinyl acetate copolymer, ethylene/acrylic copolymer, and ethylene/chlorinated polyethylene blends which have been suitably release coated, e.g., with a silicone release agent, may also be employed as release liners.
A preferred process for affixing the film l/backing 3 combination and the pressure sensitive adhesive 7 and release lin-er 8 comprises transfer lamination. In such a process a solvent solution, aqueous dispersion or hot melt of the adhesive 7 is applied to the release liner 8, and the resulting composite (ex-cept when a hot melt technique is used) is heated to dry the ad-; hesive layer 1. The adhesive side of this adhesive/liner laminatèis then laminated to the exposed surface of the backing 3, pref-~ erably at a heated lamination nlp, to form the product shown in Figure 2. The use of a heated nip insures good bonding betweenthe adhesive layer 7 and the backing 3 which may have been treated with water repellents and/or corrosion inhibitors Besides transfer lamination, the adhesive can be applied to the backing by use of conventional direct application methods using either knife, roller, reverse roller or extrusion coating techniques provided a substantially continuous and uniform coat-ing of pressure sensitive adhesive results.
When the composite article of the present invention is to -be used, the adhe~sive layer 7 is brought into contact with the vehicle substrate and, when properly positioned~ pressure is applied to securely affix it to the vehicle. This process is

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CIP of C-5066 performed in the absence of spraying solvent based adhesives or `heating the laminate/vehicle substrate combination.
The Examples which follow illustrate certain preferred em-bodiments of the present invention.

~; This Example illustrates how one preferred composite article in accordance with the present invention was made.
'; ;10 The first step ln forming the desired product was calen-dering at a temperature of about 335 C. a film formulation con-taining the following ingredients to a thickness of about 14.5 mils (0.36 mm.):
Ingredient Percent by Weight , 15 Polyvinyl Chloride Homo-polymer Resin..................... 47.745 Calcium carbonate filler........... ~14.328 , Normal alkyl phthalate plasticizer....................... 31.194 Fungicide/Plasticizer-Stabilizer......................... 1.197 Epoxidized Soya Oil~ 2~385 ; Colloidal Silica..................... 0.477 Heat sta~ilizer (Metallic soap)........~..................... 0.100 Pigment............................ .. 0.900 Barium/Cadmium/Zinc Stabilizer....................... .. I.197 Liquid Phosphite ^ Stabilizer....................... .. 0.477 To the calendered film was then applied via a roller knife technique a polymeric solution topcoat at a rate of 0.105 lbs/yd2 (0~57 kg/m2). The volatile solvent in the topcoat solution was flashed off in a drying oven at a tempera~ure of about 160F.
(71.1C.) and recovered without release to the environment. The following ingredients formed the topcoat:

CIP of C-5066 Ingredient Percent bv Weight Methyl ethyl ketone................ 89.11 PVC Homopolymer Resin.............. 7.61 Acrylic Resin...................... 2.70 Colloidal Silica................... 0.58 The topcoated vinyl film was then laminated to a non-woven substrate with a plastisol adhesive and was in-line embossed with a decorative grain at a temperature of about 320F. (160C.) which also cured the plastisol adhesive. The non-woven substrate was an all-polyester blend of 60%, by weight, 3 denier, 4 inch (10.2 cm.) staple fibers; 20%, by weight, 6 denier, 3 inch (7.6 cm.) staple fibers; and 20% by weight, 6 denier, 6 inch (15.2 cm.) staple fibers; which had been needle punched into a polyester urethane foam having a thickness of 30 mils (0.8 cm.) and a density of 2.0 lbs/ft3 (32 kg/m3). The composite non-woven/foam construction had s been fluorocarbon treated. It is a commercially available product ;- 15 from Foss Manufacturing and had a weight of 6.5 oz/sq. yd.
(0.22 kg/m2). The 30 mils (0.8 cm.) of foam was primarily on the one side of the substrate, and it was this side which was lamin-; ated to the vinyl film.

The pressure sensitive adhesive formulatior comprised these ingredients:
Ingredient Percent by Weight Self-Crosslinkable Acrylic Pressure Sensitive Adhesive Solution ("Aroset 1085").......... 77.77 Ethyl acetate solvent............... 16.67 Toluene Solvent..................... 5.56 The composition was reverse roll coated at 0.3 lbs/yd2 (0.16 kg/m~) onto 94 lbs/ream (43 kg/ream), polyethylene coated, Kraft release paper from H. P. Smith, Inc. The solvent was flashed off in a drying oven at 150-300F. (65-150 C.) and recovered.

After drying, the release paper/adhesive composite was laminated to the non-woven side of the non-woven/vinyl film construction.
In order to achieve the desired degree of penetration of the ad-hesive into the non-woven backing, the steel nip roll at the ' ClP of C-5066 lamination station was heated to about 185F, (85C.) and placed against the release paper.

The same procedure as used in Example l was employed to make a composite article using as the pressure sensitive adhesive a commercially available adhesive from Daubert Chemical Company ("DC-7025") which was used without dilution by addition of further solvent.

EX~MPLE 3 The same procedure as used in Example 1 was employed to make a composite article using as the pressure sensitive adhesive a commercially available adhesive from USM Corp. ("Bostik 7525") which was used without dilution by addition of further solvent The foregoing Examples illustrate preferred embodiment of the present invention which should not be construed in a limiting sense. The scope of protection that is sought is set forth in the claims which follow.

Claims

CIP of C-5066 What is Claimed:
1. A pressure sensitive, composite article which com-prises:
(a) a plastic film;
(b) a thick backing attached to the film on one side there-of; and (c) a substantially continuous and uniform layer of a pressure sensitive adhesive bonded to the side of the backing which is opposite the plastic film.
2. A product as claimed in Claim 1 wherein the film is a vinyl chloride polymer.
3. A product as claimed in Claim 1 wherein the film has a thickness of from about 5 mils to 25 mils.
4. A product as claimed in Claim 1 wherein the film is attached to the backing by a layer of adhesive.
5. A product as claimed in Claim 4 wherein the adhesive is a plastisol adhesive.
6. A product as claimed in Claim 1 wherein the backing is a non-woven fabric.
7. A product as claimed in Claim 6 wherein the non-woven fabric also comprises a foam layer.
8. A product as claimed in Claim 1 wherein the weight of the backing ranges from about 2 to about 20 oz/yd2.
9. A product as claimed in Claim 1 wherein the density of the backing ranges from about 2 to about 20 lbs/ft3.
10. A product as claimed in Claim 1 wherein the pressure sensitive adhesive is an acrylic pressure sensitive adhesive.
11. A product as claimed in Claim 1 wherein the adhesive layer has a thickness of from about 0.5 mil to about 10 mils.
12. A product as claimed in Claim 1 which further comprises a release liner.

13. A product as claimed in Claim 12 wherein the backing has a weight of from about 2 to about 20 oz/yd2 and a density of from about 2 to about 20 lbs/ft3.
14. A product as claimed in Claim 1 wherein the backing has been treated with a compound selected from the group consist-ing of a water repellent agent and a corrosion inhibitor.
15. A product as claimed in Claim 1 wherein the thickness of the film and backing ranges from about 20 to about 200 mils.
16. In combination, a substrate and the product of Claim 1 securely affixed thereto.
17. A combination as claimed in Claim 16 wherein the film in the product is a vinyl chloride polymer.
18. A combination as claimed in Claim 16 wherein the film in the product has a thickness of from about 5 mils to 25 mils.
19. A combination as claimed in Claim 16 wherein the film in the product is attached to the backing by a layer of adhesive.
20. A combination as claimed in Claim 19 wherein the ad-hesive in the product is a plastisol adhesive.
21. A combination as claimed in Claim 16 wherein the back-ing in the product is a non-woven fabric.
22. A combination as claimed in Claim 21 wherein the non-woven fabric in the product also comprises a foam layer.
23. A combination as claimed in Claim 16 wherein the weight of the backing in the product ranges from about 2 to about 20 oz/yd2.

CIP of C-5066 24. A combination as claimed in Claim 16 wherein the density of the backing in the product ranges from about 2 to about 20 lbs/ft3.
25. A combination as claimed in Claim 16 wherein the pres-sure sensitive adhesive in the product is an acrylic pressure sen-sitive adhesive.
25. A combination as claimed in Claim 16 wherein the ad-hesive layer in the product has a thickness of from about 0.5 mil to about 10 mils.
27. A combination as claimed in Claim 21 wherein the back-ing in the product has a weight of from about 2 to about 20 oz/yd2 and a density of from about 2 to about 20 lbs/ft3.
28. A combination as claimed in Claim 21 wherein the back-ing has been treated with a compound selected from the group con-sisting of a water repellent agent and a corrosion inhibitor.
29. A combination as claimed in Claim 21 wherein the thick-ness of the film and backing ranges from about 20 to about 200 mils