Patent GB-1103600-A (GB)
Title: Coated fabric and method of making the same
IPC: C08G18/64
Filed: 1965-01-14
Abstract: A polyurethane resin composition comprises the reaction product of an isocyanate terminated pre-polymer of an organic di-isocyanate with a polyester having at least two hydroxyl groups (or a mixture of organic di-isocyanate and a polyester having at least two hydroxyl groups in an amount sufficient to form such a prepolymer), the polyester having an average molecular weight of from 2000 to 2400, and a compatible solid resin having 0.5 to 7% by weight active hydrogen atoms and soluble in volatile inorganic solvents for the composition prior to curing, a glycol having 3 to 6 carbon atoms at least 3 carbon atoms being between hydroxyl groups, and a branch chain polyester having more than two hydroxyl groups and an average molecular weight of 2000 to 4000. Examples of straight chain, cyclo-aliphatic and aromatic di-isocyanates, and polyester diols are given and the preparation of the pre-polymer is described.  Examples of solid resins are cellulose acetate butyrate, a partially hydrolysed copolymer of vinyl chloride, and vinyl acetate, and phenoxy resins.  Examples of glycols and branch chain polyesters are given.  The composition may also contain a tetravalent organic tin salt catalysts, or other organic compounds, a surfactant such as water soluble silicones, e.g. polysiloxane polyoxyalkylene block copolymers, or nonyl phenoxy polyalkylene oxy alkanols, pigments acting as opacifiers or flattening agents.ALSO:A fabric is coated with a polyurethane resin, scuff resistant composition by coating the said composition on a releasable backing, drying to obtain a tacky surface and thereafter applying the fabric to the coating, heating the assembly to cure the polyurethane resin layer and removing the releasable backing.  A slip coating of a polyurethane-resin composition may be applied to the scuff reistant layer, dried and cured to form a laminate suitable for use in making sportswear or rainwear.  An intermediate layer of a patent leather type composition, glossy coating may be applied and dried before the application of the slip coating.  The slip coating can be deposited first on the release paper, then the scuff resistant coating applied, and finally the fabric.  The scuff resistant coating may be coated with an adhesive to adhere a layer of finely-divided fibrous material and provide a material useful for dresswear and under-garments.  The fabric can be formed of fibers of linen, nylon, cotton, rayon, silk, wool, polyester, polyacrylonitrile, modacrylic or mixtures thereof, and may be woven or non woven, and may be of the "brushed" type.  The fabric may be dyed, or treated with a resorcinol-formaldehyde resin or other adhesive, e.g. an isocyanate adhesive.  The releasable backing may be paper, nylon, or Cellophane (Trade Mark) coated with a suitable release material, e.g. a silicone, fluorinated hydrocarbons, polyproylene, polyethylene.  The polyurethane-resin composition comprises the reaction product of an isocyanate terminated prepolymer of an organic diisocyanate with a polyester having at least two hydroxyl groups (or a mixture of organic diisocyanate and a polyester having at least two hydroxyl groups in an amount sufficient to form such a prepolymer), the polyester having an average molecular weight of from 2000 to 2400, a compatible solid resin having 0.5 to 7% by weight active hydrogen atoms and soluble in volatile organic solvents for the composition prior to curing, a glycol having say 3 to 6 carbon atoms at least 3 carbon atoms being between OH groups, and a branched chain polyester having more than 2 hydroxyl groups and an average molecular weight of 2000 to 4000; in a volatile organic solvents such as low molecular weight ketones, or mixtures of ketones with aromatic hydrocarbons, esters.  Examples of straight chain, cycloaliphatic and aromatic diisocyanates, polyester diols and solvents are given and preparation of the prepolymer is described. Examples of solid resins are cellulose acetate butyrate; a terpolymer of vinyl chloride, acetate and maleic acid or other dibasic acid; a copolymer of vinyl chloride and beta hydroxy ethyl acrylate; a terpolymer of vinyl chloride, methyl methacrylate, and beta hydroxy ethyl acrylate; a copolymer of vinyl chloride and vinyl acetate; phenoxy resins.  Examples of glycols and branched chain polyesters are given.  The slip composition coating is the same as the scuff resistant layer except that only aliphatic diisocyanates are employed, and resin in amount greater than said diisocyanate and the polyester diol or in ratios by weight to the prepolymer of 125:100 to 225:100 is used and the total amount of diisocyanate is less than the total amount of active hydrogen groups of the polyester diol and of the resin.  The resin may be partially replaced with polyvinyl chloride.  The slip may be improved by using a coating prepared on an embossed carrier.  The scuff resistant coating composition may contain: a tetravalent p  organic tin salt catalyst of formula RxSn.(O OR')y where x is 1 to 3 and y is 3 to 1, R is an alkyl group of 2 to 8 carbon atoms and R' is an aliphatic hydrocarbon group of 6 to 18 carbon atoms or other organo metallic compounds; a surfactant such as water soluble silicones, e.g. polysiloxane polyoxyalkylene block copolymers or nonyl phenoxy polyalkylene oxy alkanols; finely-divided pigments or mixtures of pigments acting as opacifiers of flattening agents, e.g. calcium carbonate, silica, calcium silicate, phthalocyanine green, phthalocyanine blue, iron oxide, titanium dioxide, carbon black, bone black, chrome yellow, toluidine reds, cadmium reds, cadmium yellows; lecithin to improve levelling, antioxidants.  The slip composition may also contain a tetravalent tin salt catalyst of the kind described, and flatting agents such as silica, calcium silicate, polyvinyl chloride or polymethyl methacrylate resins.  The glossy coating comprises a polyester triol having an OH number of 300 to 400 and an organic triisocyanate in amount sufficient to cure the polyester triol and volatile organic solvents, e.g. ketones and esters.  The polyester triol may be castor oil triol and the preparation of other polyester triols is described. The triisocyanate may have 4 to 22 carbons between isocyanate groups, and examples are: straight chain isocyanates such as the reaction product of kexomethylene, keptamethylene, decamethylene and other aliphatic diisocyanates having 4 to 10 carbon atoms between NCO groups with water; hydrogenated methylene triphenyl isocyanate and other saturated triisocyanate naphthalene triisocyanate; p, p', p"-triphenyl methane triisocyanate, and the phosgenated product of the reaction between aniline and formaldehyde.  The composition may also contain a tin catalyst as described.  The adhesive may be: the polyurethane prepolymer of the scuff resistant layer dissolved in ethylene dichloride and containing a tertiaryamine catalyst; an aqueous emlusion of a curable composition of a copolymer of ethyl acrylate and methacrylic acid.  The finely-divided, fibrous material may be any natural or synthetic fiber such as rayon, cotton, linen, nylon, wool, silk, polyester and mixtures thereof.  Finely divided aluminium and bronze powders may be used, and also in the scuff resistant coating or slip coating, to impart opacity and light reflectivity.  The coatings may be formed using printing rolls, doctor blades, by spraying, and may be dried or cured by means such as drying ovens, exhaust fans, infra red, dielectric heating, conduction heating.  In Figure 1 (not shown), release paper 1 from roll 2 is coated with scuff resistant composition from supply tank 6 by passing under roller coater 4, passed through heating chamber 12 having two heating zones 13 and 14 to from a tacky layer, solvent vapours being exhausted through stock 15.  More than two heating zones may be used of varying temperatures or only one heating zone can be used of constant temperature or containing a number of heating means at various temperatures.  The coated paper 8 passes over carrier rolls 20 and 21 whilst roller 22 spreads out fabric 23 from roll 24 into contact with the laminate 8 with light pressure, i.e. the fabric is "kiss-coated" on to laminate 8 to make laminate 25, which then passes over heating rolls 30, 31, 32 and 33 maintained at 220 DEG F to partially cure the urethane layer and wound on roll 37. Roll 37 is then stored in air at ambient temperature to complete the curing.  In Figures 5 of the drawings (not shown), a slip coating layer is applied by a printing roller and dried in an oven, and in Figure 7 (not shown) an adhesive layer is applied by a printing roller, and apparatus for applying the finely-divided fibrous material is shown, with final drying and curing of the adhesive in a drying oven.