Patent GB-992261-A (GB)
Title: A process for making and finishing artificial hides or leathers
IPC: D04H1/64
Filed: 1962-02-28
Abstract: A method of producing an artificial leather comprises impregnating a lap of fibres with latex, heating the impregnated lap to 60-80  DEG C. to coagulate the latex and thereby bind the lap, squeezing the impregnated lap until the water content is 20-50% of its total weight and drying the impregnated lap.  The lap may then be coated with either (1) a plurality of coats of an aqueous resinous coating composition containing casein, an anti-fermenting agent, one or more resins selected from butadiene-acrylonitrile copolymers, butadiene-styrene copolymers, polyvinyl chloride and aliphatic polyesters of acrylic and methacrylic acid, at least one plasticizer and, if desired, one or more pigments and fillers, and heating the coated lap after each coating to a temperature sufficient to dry the lap, or with (2) at least one coat of a coating composition comprising polyvinyl chloride and at least one plasticizer and, if desired, one or more resins selected from butadiene-acrylonitrile copolymers, butadiene-styrene copolymers, and aliphatic poleysters of acrylic and methacrylic acid, and pigments and fillers and heating the coated lap after each coating to a temperature sufficient to gel the said coat.  Preferably textile fibres, e.g. cotton, rayon, nylon and acetate fibres and their waste or combinations thereof are formed into a web in a carding engine, and by laying such webs on one another a lap of the desired thickness is formed.  The lap is then dipped into an aqueous bath containing natural or synthetic latex or mixtures thereof and is then put in an oven at a temperature of 200-300  DEG C. to coagulate the latex.  The latter is produced when its temperature reaches 60-80  DEG C. and binds the lap together. Excess water is then squeezed out, e.g. by passing the lap through rollers, until the water content is from 20-50% of the total weight of the material so that on drying, the space occupied by water in the material is replaced by air cells which gives the material a certain porosity. When dry the lap may be coated by spray, brush or calender means as indicated above.  The coats may consist of one first coat, one or more intermediate coats and two final coats, the first coat containing a wetting agent, the intermediate coats containing less plasticizer than the first coat and the final coats containing no pigments or fillers.  The coating composition (2) above may be in an amount of 70-300 gm./sq.metre and is preferably between 70 and 150 gm./sq.metre.  The filler in the coating composition (1) above may be zinc stearate and the anti-fermenting agent may be formaldehyde.ALSO:A method of producing an artificial leather comprises impregnating a lap of fibres with latex, heating the impregnate lap to 60 to 80 DEG C. to coagulate the latex and thereby bind the lap, squeezing the impregnated lap until the water content is 20 to 50% of its total weight and drying the impregnated lap.  The lap may then be coated with either (1) a plurality of coats of an aqueous resinous coating composition containing casein, an anti-fermenting agent, one or more resins selected from butadiene-acrylonitrile copolymers, butadiene-styrene copolymers, polyvinyl chloride and aliphatic polyesters of acrylic and methacrylic acid, at least one plasticizer, and, if desired, one or more pigments and fillers, and heating the coated lap after each coating to a temperature sufficient to dry the lap; or with (2) at least one coat of a coating composition comprising polyvinyl chloride and at least one plasticizer and, if desired, one or more resins selected from butadiene-acrylonitrile copolymers, butadiene-styrene copolymers, and aliphatic polyesters of acrylic and methacrylic acid, and pigments and fillers and heating the coated lap after each coating to a temperature sufficient to gel the said coat.  Preferably textile fibres e.g. cotton, rayon, nylon and acetate fibres and their waste or combinations thereof are formed into a web in a carding engine, and by laying such webs on one another a lap of the desired thickness is formed.  The lap is then dipped into an aqueous bath containing natural or synthetic latex or mixtures thereof and is then put in an oven at a temperature of 200 to 300 DEG C. to coagulate the latex.  The latter is produced when its temperature reaches 60 to 80 DEG C. and binds the lap together. Excess water is then squeezed out, e.g. by passing the lap through rollers, until the water content is from 20 to 50% of the total weight of the material so that on drying, the space occupied by water in the material is replaced by air cells which gives the material a certain porosity.  When dry the lap may be coated by spray, brush or calender means as indicated above.  The coats may consist of one first coat, one or more intermediate coats and two final coats, the first coat containing a wetting agent, the intermediate coats containing less plasticizer than the first coat and the final coats containing no pigments or fillers.  The coating composition (2) above may be in an amount of 70 to 300 gm/sq. metre and is preferably between 70 and 150 gm/sq. metre. The filler in the coating composition (1) above may be zinc stearate and the anti-fermenting agent may be formaldehyde.