| 摘要 |
Siloxane emulsions for waterproofing fibrous materials (see Division D1) comprise a heat-curable organopolysiloxane and as emulsifier a polyvinyl alcohol or a modified polyvinyl alcohol obtained from a polyalkylene glycol by graft polymerization with polyvinyl acetate and subsequent hydrolysis, and in the aqueous phase of the emulsion a catalyst which comprises (a) an ester of titanic or zirconic acid with a tertiary aliphatic amine carrying at least two b -hydroxyalkyl groups and (b) a water-soluble zinc or cadmium salt with an organic acid, and where (a) is a titanic acid ester, a tri-(b -hydroxylalkyl)-amine as a further component (c). The siloxanes used may contain Si-bonded saturated or unsaturated aliphatic or aromatic hydrocarbon radicals, H atoms or OH groups. The alkanolamine titanates and zirconates (a) used are described in Specification 755,728 and Belgian Specifications 555,021, 558,728 and 595,878. Catalysts (b) specified are the Zn and Cd salts of formic, acetic, propionic and chloracetic acids. Preferably 2-7% of (a), 4-8% of (b) and 7-10% of (c) are used, based on the weight of the siloxane. Amino-plast pre-condensates may also be added. The siloxane is subsequently heat-cured on the fibrous material. In a typical Example (1) an aqueous solution of triethanolamine zirconate and zinc acetate dihydrate was added to an aqueous silicone emulsion containing a liquid methyl hydrogen polysiloxane, xylene and, as emulsifier, a modified polyvinyl alcohol obtained by graft polymerization of polypropylene glycol with polyvinylacetate and subsequent hydrolysis. Specifications 792,593 and 792,594 also are referred to.ALSO:Fibrous materials are rendered water-repellent by impregnating them with a siloxane emulsion comprising a heat-curable organopolysiloxane and, as emulsifier, a polyvinyl alcohol or a modified polyvinyl alcohol obtained from a polyalkyleneglycol by graft polymerization with polyvinylacetate and subsequent hydrolysis, and in the aqueous phase of the emulsion a catalyst which comprises (a) an ester of titanic or zirconic acid with a tertiary aliphatic amine carrying at least two b -hydroxyalkyl groups and (b) a water-soluble zinc or cadmium salt with an organic acid, and where (a) is a titanic acid ester, a tri-(b -hydroxyalkyl)-amine as a further component (c), (see Division C3) drying the impregnated material at temperatures up to 110 DEG C. and subsequently heat-curing the siloxane at 120 DEG to 200 DEG C. for up to 10 minutes. In the examples a cotton poplin is treated in the above manner. Specifications 755,728, 792,593, 792,594 and Belgian Specifications 555,021, 558,728 and 595,878 are referred to. |
