Patent GB-1010097-A (GB)
Title: Improvements in or relating to open-fibred collagenous masses and methods of making same
Inventor: SHU-TUNG-TU
IPC: C08L89/06
Filed: 1962-03-12
Abstract: 1,010,097. Bonded fibrous fabrics. UNITED SHOE MACHINERY CORPORATION. March 12, 1962, No. 9337/62. Heading D1R. A leather-like material is produced by distributing an aqueous solution of skin proteinous material precipitable by a chrome tanning agent through a mass of collagen fibres and causing precipitation of the skin proteinous material among the collagen fibres. The fibrous mass may be treated first with the proteinous material and then with a polyfunctional linking agent, namely a chrome complex tanning agent, or vice versa. The skin proteinous material may be obtained by hydrolysis of hides, skins, bones, hoofs, glur, &c. The aqueous solution of proteinous material may be a tropocollagen solution prepared as described in Specifications 927,282 and 979,310 or a gelatin solution prepared as described in Specification 992,585. A chrome tanning agent is not necessarily used to carry out the method. If a gelatin solution is used the molecules thereof are converted into fibrous insoluble material through the action of polyfunctional linking agents e.g. a chrome complex tanning agent, other inorganic salts such as those of aluminium, ferric iron, titanium and zirconium, and organic cross linking agents such as aldehydes and certain hydroxylcontaining compounds. Precipitation of the proteinous material is preferably effected by water soluble compounds of trivalent and hexavalent chromium, e.g. compounds formed by partially neutralizing chromic salts such as chromic chloride and chromic sulphate. The collagen fibres are preferably obtained by lightly tanning skin with formaldehyde or glutaral  dehyde, beating with added water to form individual fibres or clumps of fibres, and finally dewatering, all under controlled pH conditions as described in Specifications 927,282 and 957,783. If carded or garnetted webs of dry collagen fibres are employed more than one layer thereof may be used with the direction of fibres of one layer at an angle to the direction of fibres of an adjoining layer. The dry fibres are preferably sprayed with water before the application of the skin proteinous material or may be impregnated with an emulsion or dispersion of a tropocollagen or gelatin solution in a non-aquous continuous phase. An open fabric, e.g. netting having openings from <SP>1</SP>/ 32  to <SP>3</SP>/ 16  inch across, may be incorporated as part of the collagen fibre sheet to orient fibres perpendicular to the surface thereof to impart tensile strength thereto. The leather-like material may be dried and treated with an agent to inhibit further water bonding. Suitable agents include hydrophobic oily or fatty materials such as oleic acid which may be introduced in emulsion or solution form, e.g. on a methanol solution, synthetic resinous or rubbery components such as natural rubber latex, butadiene acrylonitrile copolymer synthetic rubber latices, polyvinyl chloride and polyvinyl chloride-acetate latices. The material may be subjected to needling as described in Specification 960,830 and may then be coated with a fluid hardenable polymer and plated, pressed or embossed. In the apparatus shown, a fluid slurry of collagen fibres are spread on a porous paper layer 26 on a foraminous screen 14 in a shell 10. A cover 16 is secured in place and a valve 24 in an inlet 20 is closed. Air under pressure is supplied through a pipe 18 to force liquid from the slurry to a discharge outlet 12. Air pressure is released, the aqueous solution of proteinous material is introduced through a funnel 28 and air pressure applied to force the proteinous material into the fibrous layer. The sheet is removed from the apparatus and immersed in a chrome tanning agent. Alternatively the slurry may be treated with the tanning agent before being supplied to the apparatus shown.