Patent GB-805372-A (GB)
Title: Improvements in or relating to rendering organic fibrous materials water-repellent
IPC: D06M13/395
Filed: 1956-01-30
Abstract: Surfaces of metal, glass, ceramic and organic plastics are given protective coatings and organic fibrous material including paper, wood and leather is given a water-repellent finish by applying thereto, e.g. by dipping, brushing, spraying or flooding, a composition comprising (1) a siloxane copolymer of 1 to 50 mol. per cent of units of the formula <FORM:0805372/III/1> in which R is a divalent saturated aliphatic hydrocarbon radical containing at least 3 carbon atoms, the hydroxyl group being attached to a carbon atom which is at least 3 carbon atoms away from the silicon, R1 is a monovalent hydrocarbon or halogenated hydrocarbon radical free from aliphatic unsaturation, and n is from 0 to 2, from 50 to 99 mol. per cent of dimethylsiloxane and 0 to 35 mol. per cent of monomethylsiloxane; and (2) a polyisocyanate, and curing the resin, preferably by heating to 150 DEG  to 250 DEG  C.  The hydroxyl containing siloxanes are described in Specification 769,497, [Group IV (a)].  The amount of isocyanate, of which a number is specified, is preferably in excess of that required to react with all of the hydroxyl groups. The compositions are preferably applied as solutions.  In Example (3), a sheet of iron is coated with a 70 per cent toluene solution of a copolymer of 50 mol. per cent dimethylsiloxane, 35 mol. per cent monomethylsiloxane and 15 mol. per cent of isomers of the formula <FORM:0805372/III/2> and containing m-toluene diisocyanate, and is cured at 250 DEG  C.ALSO:A composition for rendering fibrous material water-repellent comprises (1) a copolymer of from 1 to 50 mol. per cent of a siloxane of the general formula <FORM:0805372/IV (a)/1> in which R is a divalent saturated aliphatic hydrocarbon radical containing at least 3 carbon atoms, the hydroxyl group being attached to a carbon atom which is at least 3 carbon atoms away from the silicon, R1 is a monovalent hydrocarbon or halogenated hydrocarbon radical free from aliphatic unsaturation, and n is from 0 to 2, and from 50 to 99 mol. per cent of a siloxane of the general formula <FORM:0805372/IV (a)/2> in which R11 is a monovalent hydrocarbon or halogenated hydrocarbon radical, m is from 1 to 3, p is 0 to 1, and m + p does not exceed 3; and (2) a polyisocyanate.  The hydroxyl-containing siloxanes and copolymers thereof are described in Specification 769,497.  Examples of polyisocyanates are toluene-2,4-diisocyanate, 2 - nitrodiphenyl - 4,41 - diisocyanate, 2 - nitrodiphenylmethane - 4,41 - diisocyanate, diphenylmethanesulphone - 4,41 - diisocyanate, diphenylsulphone - 4,41 - diisocyanate, naphthalene - 1,4 -, 1,5 -, and 2,7 - diisocyanates, fluorene- and chrysene - diisocyanates, and butylate, hexamethylene, octadecylene, cyclohexylene and cyclopentylene diisocyanates.  The amount of isocyanate is preferably greater than is required to react with all of the hydroxyl groups.  The compositions are preferably applied as solutions in solvents such as hydrocarbons, chlorinated hydrocarbons, ethers and isopropyl ketone. The compositions may also be used for coating on other materials such as metals, glass, ceramics and organic plastics. Complete curing is obtained by heating at 150 DEG  to 250 DEG  C.  In the examples: (1) methyl hydrogen dichlorosilane is cohydrolysed with gammaacetoxy propylmethyl dichlorosilane in toluene, the solution is diluted with toluene and methanol, a catalytic quantity of benzene sulphonic acid is added, and the solution allowed to stand for 7 days.  After washing and drying, a solution of a copolymer of 15 mol. per cent of gammahydroxy propylmethylsiloxane and 85 mol. per cent of methyl hydrogen siloxane is obtained.  A composition is made up of this solution with m-toluene diisocyanate in toluene; (2) a copolymer of 55 mol. per cent PhMeSiO, 15 mol. of PhSiO3/2, 15 mol. per cent PhSiO3/2, 15 mol. per cent MeSiO3/2 and 15 mol. per cent of isomers of the formula <FORM:0805372/IV (a)/3> is dissolved with m-toluene diisocyanate in toluene to give a 2 per cent solution combined materials; (3) a copolymer of 50 mol. per cent Me2SiO, 35 mol. per cent MeSiO3/2 and 15 mol. per cent of isomers of the formula <FORM:0805372/IV (a)/4> is prepared in toluene and m-toluene diisocyanate is added; (4) the copolymer is one of 85 mol. per cent Me2SiO and 15 mol. per cent HO(CH2)3SiO1,5; (6) the copolymer is of 10 mol. per cent ViMeSiO, 20 mol per cent ClC6H4SiO1,5, 25 mol. per cent <FORM:0805372/IV (a)/5> 10 mol. per cent F2C=CFSi(Me)O, 20 mol. per cent HO(CH2)3SiO1,5 and 5 mol. per cent HO(CH2)3(ClC6H4)Si(Me)O0,5; (7) th copolymer is 77.5 mol. per cent MeHSiO, 7.5 mol. per cent Me2SiO and 15 mol. per cent HO(CH2)3 Si(Me)O, dissolved in a mixture of toluene and isopropyl ketone.