US3087848A - Method of making automobile top material - Google Patents

Description

April 30, 1963 J. w. RASH 3,087,848

METHOD OF MAKING AUTOMOBILE TOP MATERIAL Filed May 1, 1958 WATEE REPELLE NT INVENTOR JOHN W. RASH ATTO R N EY United States Patent 3,087,848 METHOD OF MAKING AUTOMOBILE TOP MATERIAL John W. Rash, Westfield, NJL, assignor to Interchemical Corporation, New York, N.Y., a corporation of Ohio Filed May 1, 1953, Ser. No. 732,390 1 Claim. (Cl. 156-280) This invention relates to a combined coated fabric specifically designed for use as top material for convertible automobiles, and aims to provide such a coated fabric characterized by excellent resistance to weather, high strength, good flexibility, pleasing appearance and excellent sound absorption characteristics.

Convertible automobile tops have generally been covered with fabric, which must have certain definite characteristics. It must be water-repellant to keep out the rain; it must be flexible so that it folds well when the tops are put up and down; and the fabric must have sufficient mechanical strength to resist accidental impact in the raising and lowering operation.

Originally, heavy waterproofed textile fabrics, either single thickness or laminated, were used for such tops, generally dyed with vat dyes to give some degree of resistance to fading. Such tops were water-repellant and had the desired flexibility and mechanical strength when new; they also had the additional desirable property of absorbing sound. But they did not stand up well on weathering; the fabric deteriorated under the influence of sun, rain and weather, so that such top fabrics required replacing after a relatively short time.

Coated fabrics, which were widely used on fixed tops of automobiles before the all-steel bodies came into use, were early suggested as potential replacements for the simple dyed waterproofed fabrics. However, while coated fabrics are generally substantially more weatherresistant than uncoated fabrics, the flexibility requirements of the convertible top rule out a very large percentage of all coated fabrics. Most products which are flexible enough unweathered and for a few bendings, lose their flexibility after repeated bendings and/ or weathering. Furthermore, as the fabric structure is built up to give higher mechanical strength, the overall flexibility of the system suffers. In addition, the coating of the fabric, where the coating is designed for optimum weather resistance, will often change the characteristics of the base fabric, so that the desirable sound absorption characteristics of the fabric are lost.

It is an object of the present invention to produce a coated fabric for use in convertible automobile tops which has good mechanical strength, has a permanent pleasing appearance on both sides, is sufliciently flexible after repeated flexings to be foldable on lowering of the top over long periods of time, is sufficiently waterproof and water-resistant on both the upper side and the underside to keep out water over extended periods of use, and yet has the desirable sound absorption capacity on the inside of the automobile characteristic of uncoated fabric.

Another object of the present invention is an improved method of producing such a fabric characterized by the fact that waterproofing of the underside of the fabric, and shrinkage of the complete fabric are obtained with a single treating agent.

According to the present invention, these objects are obtained by coating-either before or after lamination-a relatively light strong textile fabric with a pigmented weather-resistant resinous coating, preferably a plasticized polyvinyl chloride coating, preferably applied by the plastisol method, laminating the coated fabric by the use of an elastomeric adhesive to a second fabric,

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printing the free side of the second fabric with a very thin film of pigmented ink, preferably in a design simulating a textile, and making the uncoated fabric waterrepellant without completely coating the threads, preferably by applying an aqueous emulsion of an agent which makes the fabric water-repellant without forming a continuous coating over the fabric, rolling the fabric and holding for 4 to 8 hours to permit the water to shrink the structure, and then unrolling and drying the fabric without tension thereon.

The resultant coated combined fabric is illustrated in cross-section in the accompanying drawing. It comprises a weather resistant pigmented resinous coating 10, preferably a plasticized polyvinyl chloride coating laid down by the plastisol process, carried by a textile fabric 12, which is laminated by means of a layer of elastomeric adhesive 14 to a textile fabric 16, which is Waterproofed by a Water repellent agent, which does not coat the textile, but acts despite the open nature of the textile, the textile bieng decorated with a thin ink film '18, preferably laid down in such a pattern as to resemble an unprinted dyed textile.

The textile fabrics which are to be combined into the laminated coated fabric are selected to give the desired strength; they may be of cotton, rayon or synthetic fibers such as nylon, cellulose acetate, Dacron polyester fiber, and the like. The stronger synthetics, used alone or blended with cotton, give stronger fabrics at equivalent weights and thickness than cotton fabrics. The choice is a matter largely of economics. The weaves are chosen for smoothness and strength-sheetings, drills, twills and sateens are typical.

With cotton fabrics, the finished thickness of the finished coated fabric will range between about .025 and .040 inch; weightwise, the fabric will represent about 30% to 40% of the composite material.

The topcoating is picked for its original flexibility and its resistance to weathering; it must retain this flexibility after prolonged weathering and after repeated flexing. Pigmented plasticized polyvinyl chloride by which is meant either the homopolyer, or any copolymer with small amounts of other materials such as vinyl acetate, maleic anhydride, etc.-is a preferred material. The coatings may be applied to the top fabric by calendering or controlled solution coating, and the coated fabric so produced laminated to the second fabric; or the fabric may be laminated before coating, and the polyvinyl chloride coating be applied by the plastisol techniquei.e., as a dispersion in a plasticizer, followed by heat to fuse the resin and dissolve it in the plasticizer to form I the desired tough coating.

. binders can be used which have these properties.

The fabrics may be combined with any cured elastomeric adhesive, made of natural or any synthetic rubber. These adhesives, when formulated with the necessary antioxidant and cured, are permanently flexible unless exposed directly to weathering. In the combined fabric, they are protected by the polyvinyl chloride topcoat against the direct weather exposure of the car top and by the water-proofed bottom textile against the indirect exposure inside the car. In general, to ease the combining, the adhesives are spread on both fabrics and are then joined face to face with heat and pressure, and cured.

The printing ink used for printing the design on the bottom of the fabric must employ light-fast pigments, and have weather-resistant properties. A wide range of We have used inks based on Epon resins (bis-phenol epichlorhydrin condensates) on cellulose acetobutyrate, on various polyvinyl chloride copolymers, on polyvinylidene chloride copolymers, on polyacrylate resins of various sorts, and on alkyd resins; it appears that if the pigments are light-fast, any binder of even moderate weather resistance is adequate to protect the pigment against the relatively mild weather conditions experienced on the bottom side of the fabric. Particularly satisfactory inks are those shown in the Booth United States Patent 2,691,005, issued October 5, 1954.

It should be noted that the printing ink, which is preferably deposited in a pattern resembling a dyed textile, is so thin and discontinuous that it provides only a very slight diminution of the sound absorbing capacity of the fabric.

This desirable feature is retained in the water-repellancy treatment by using any of the known hydrophobic materials which will give textile materials waterrepellancy without a continuous coating. Such known materials include wax emulsions and emulsions of water insoluble metallic soaps; somewhat better results are obtainable by treatment with materials which give waterrepellancy with somewhat lower concentrations of agent-- e.g., the chlorosilanes, which convert on the fabric to alkyl polysiloxanes, the stearamidomethyl pyridinium and similar halides (Zelan) and the polymerizable fluorocarbons which are converted on the fabric to water-repellant polymers (e.g., Minnesota Mining Scotchgard PC 149).

As indicated above, these water-repellents are preferably applied to the fabric in aqueous dispersion, and the fabric is rolled up and held for 4 to 8 hours, following which the fabric is dried without tension (as by festoonning) to convert the water-repellent to the desired form. Shrinkage control is thus obtained in a single operation together with water-repellency.

Example I In a typical process for practicing the invention, a 2.10 cotton sheeting (2.10 linear yards per pound ona 56 inch width basis) of a thread count 64 x 64, using #21 carded cotton yarn for the warp and #25 carded cotton yarn for the fill, was employed as top sheet, and a 1.95 cotton drill, 68 x 40 count, with a #21 warp and #14- fill, was employed as the bottom sheet.

Each of the fabrics was coated with an adhesive com-' position having the following formula, using a total of 9 ounces adhesive (solid basis) per linear yard (56 inches wide) of combined material:

Lbs. Ozs

Eniay Butyl #268 (Bntyl rubber) 50 Soft Clay 37 0 Silene (Calcium silicate) 2 8 Zinc Oxide. 2 8 Sulfur l2 Altax (Benzothiazyl snlfide).. 4 Methyl Zimate (Zinc dimethyl dithiocarbamate) 8 Staybelite Resin (Stabilized rosin) 12 Aluminum Stenratc l 0 Titanium Dioxide 5 0 The two sheets were laminated together by passing between a steel and rubber roller, under pressure; curing took place partially by heating the rolls, and partially in the remainder of the process.

The combined sheet was coated with a vinyl plastisol, using about 13.5 ounces per'linear yard of 56 inch material and of the following composition:

Parts by weight Pigment dispersion-55% TiO 45% Flexol 8N8--- 10% vinyl acetate) 10 Acryloid A101 (40% solution of polymethyl methacrylate in methyl ethyl ketone) 11 Paraplex G50 (Rohm & Haas-polymeric polyester plasticizer) 5 Heat and light stabilizer for polyvinyl chloride (as in the vinyl plastisol) /z Solvent (half acetone-half toluene) 55 /2 The design was an engraved gravure plate simulating a textile weave, giving the underside of the fabric the appearance of a dyed fabric.

Finally, the fabric was padded with a thin aqueous dispersion of a water-repellant agent-Arkansas Chemical Companys clear. Hydropruf, which is a chlorosilanc which converts on the fabric to an alkyl polysiloxane (4% solids as applied). The wet fabric was rolled, and held 6 hours; it was then dried without tension, in a festooned rack, at a temperature of 220 F.

The resultant fabric is strong, flexible, weather resistant after prolonged use, and the underside has the appearance and desirable sound absorbency properties of ordinary fabric for the inside of an automobile when the top is up; at the same time, the underside will not fade or deteriorate in the manner of ordinary dyed underside fabrics of the prior art.

Example 11 Instead of proceeding as above, the top fabric may be coated first, and then combined. Thus, using the same fabric as in the above example, the 2.10 cotton sheeting was coated by calendaring on 14 ounces per linear yard of 56 inch material of a composition comprising:

Part by weight Vinylite VYNS (copoly-mer of vinyl chloride,

The calendered coated fabric was combined with the 1.95 drill as in Example I, or it may be combined by usmg a rubber cement made by compounding, on a rubber mill Part by weight Smoked sheets (natural rubber) 57.5 Clay 23.0 Zinc oxide 2.8 Benzothiazyl disulfide 0.6 Zinc dibutyl thiocarbamate 0.05 Antioxidant [2-2 methylene bis(4 methyl 6 tertiary butyl phenol)] 1.20

Titanium dioxide 14.00

and dissolving this compound in the ratio of 35 parts by weight compound to 35 parts by weight of any suitable solvent, such as a gasoline range petroleum distillate. The cement is coated on both fabrics, allowed to become tacky, and the fabrics combined as in Example I; the rubber cement is partially cured in combining, partially during further processing.

In this example, the inner fabric was printed with an ink made in accordance with the Booth Patent 2,691,005, issued October 5, 1954; the ink was set by heating the fabric, which heat acted also to help cure the rubber cement.

The fabric was made water-repellent by treatment with aqueous zirconium acetate, in conventional fashion; the wet fabric was treated as in Example I, to shrink the fabric along with the water control treatment.

The above examples can be carried out with preshrunk fabric, in which case no care need be exercised in the drying of the Wet combined fabric. The resinous topcoating employed may be applied as plastisol or by calendering, or it may be applied by coating solutions of resins, using a multiplicity of coats to build up the desired film thickness. Any weather resistant resinous coating can be used, the preferred coatings being of polyvinyl chloride (including copolymers with minor portions of active ingredients). Further, as indicated above, various adhesive may be used, as long as they are of curable elastomeric material, and any light-fast inks may be employed, which do not completely coat the fabric.

Obviously, the examples given above are not exhaustive and can be widely modified, as indicated above, by utilizing any of the topcoats, adhesives or inks which have been indicated as useful, without departing from the invention which is defined in the claim.

What is claimed is:

The method of producing convertible automobile top material which comprises preparing a combined fabric comprising two woven textile fabrics united by an elastomeric adhesive and coated on one face with a weatherresistant pigmented plasticized polyvinyl chloride coating, printing the back of the combined fabric with a lightresistant ink, soaking the back of the fabric in an aqueous dispersion of an agent capable of making the fabric back water-repellent without producing a continuous coating, rolling up the wet fabric, holding it rolled for 4 to 8 hours, and finally unrolling and heating while free of tension to drive out the water to simultaneously shrink the composite fabric and set the water-repellent agents.

References Cited in the file of this patent UNITED STATES PATENTS 815,307 Odell Mar. 13, 1906 \1,-18 5,067 Colburn May 30, 19 16 2,098,754 Nickowitz Nov. 9, 1937 2,431,745 Flanagan Dec. 2, 1947 2,527,299 De Phillips Oct. 24, 1950 2,533,976 Teague Dec. 12, 1950 2,779,035 McMunry Jan. 29, 1957

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