Patent GB-809766-A (GB)
Title: Improvements in or relating to organohydrogenosiloxane emulsions and the treatment of fabrics therewith
IPC: C08G77/00
Filed: 1957-06-21
Abstract: A catalyst comprising an aqueous solution of zirconium acetate and zinc acetate in amounts such that there is from 0.1 to 4.5 zinc atoms per zirconium atom, is used in curing liquid organopolysiloxanes. The solution may be heated at 35 DEG  to 100 DEG  C. before use.  The catalyst solution is added to an aqueous emulsion of an organopolysiloxane of formula <FORM:0809766/III/1> where R is an alkyl radical of 1 to 5 carbon atoms, a is 1.0 to 1.5, b is 0.75 to 1.25, and a+b is 2.0 to 2.25, and the emulsion is used to impregnate organic fabrics, which are then heated to cure the polysiloxane and render the fabrics waterproof.  Examples of compositions containing the catalyst are given. Specifications 680,265, 686,212, 762,819, 766,864 and 790,038, [all in Group IV (a)], are referred to.ALSO:An emulsion for waterproofing materials comprises (1) a liquid organopolysiloxane of formula <FORM:0809766/IV (a)/1> where each R is an alkyl radical having 1 to 5 carbon atoms or an aryl radical, there being not more than 10 molar per cent of aryl-substituted silicon atoms, a is 1.0 to 1.5, b is 0.75 to 1.25 and a + b is 2.0 to 2.25; (2) zirconium acetate and zinc acetate in a ratio of 0.1 to 4.5 zinc atoms per zirconium atom; and (3) an emulsifying agent.  Preferably the organosiloxane constituents of the emulsion consist of a mixture of 5 to 80 per cent by weight of the abovementioned <FORM:0809766/IV (a)/2> polymer and 20 to 95 per cent by weight of (A) a liquid organopolysiloxane having a viscosity of 1000 to 100,000 CS at 25 DEG C. and having the formula <FORM:0809766/IV (a)/3> where R1 is an aliphatic hydrocarbon radical having 1 to 5 carbon atoms or an aryl radical, there being not more than 10 molar per cent of aryl-substituted silicon atoms present, and x is 2.0 to 2.1; and/or (B) a liquid hydroxylated organopolysiloxane having a viscosity less than 1,000,000 CS. at 25 DEG  C., and having an average of 1.4 to 2 organic radicals attached to silicon per silicon atom, each organic radical being an aliphatic hydrocarbon radical of 1 to 5 carbon atoms or an aryl radical, there being not more than 10 molar per cent of aryl-substituted silicon atoms present.  The emulsion may contain sufficient zirconium acetate to provide 0.25 to 30 per cent by weight of zirconium calculated as the metal based on the total organopolysiloxanes present. Materials are wetted with the emulsion and cured by drying at 80 DEG  to 95 DEG  C.  The emulsion may also contain the reaction product of a di- or tri-alkanolamine with an alkyl titanate.  Examples are given.  Specifications 680,265, 686,212, 762,819, 766, 864 and 790,038 are referred to.ALSO:A reaction product or complex is formed by heating zinc acetate and zirconium acetate in water at 35 DEG  to 100 DEG  C. for a short time (e.g. 10 minutes to 1 hour), or by allowing a solution of the salts to stand at room temperature for a longer time (e.g. 24 hours).  The ratio of zinc acetate to zirconium acetate is such that there is 0.1 to 4.5 zinc atoms per zirconium atom.  The zirconium acetate which is used above is prepared by the reaction of acetic acid on basic zirconyl hydroxide, Zr2O3(OH)2, and has the empirical formula H2ZrO2(OOC.CH3)2.  Speci fications 680,265, 686,212, 762,819, 766,864, [all in Group IV (a)], and 790,038 are referred to.