process for the production of a vacuum and exclusion of water lagerfaehigen organpolysiloxanmassen in the presence of water at room temperature to haerten elastomers

摘要

Liquid compositions which are moisture-free, vulcanisable in the presence of water and which are stable in storage, comprise a linear siloxane of the formula R2SiO, in which R is a hydrocarbon radical, and containing at least 0,1% Si-bonded OH groups, and from 0,5 to 25% (by weight of the siloxane) of an organotriacyloxysilane of the formula R 1Si(OCOR11)3 wherein R1 is a lower alkyl, alkenyl, aryl or aralkyl radical and R11 is an alkyl group of 1 to 18 C atoms or an aryl group. Moisture-free loading agents of fillers, e.g. ZnO, CdO, CaCO3, SiO2, diatomaceous earth and iron oxide, and solvents, e.g. toluene and xylene, may also be added. In application the compositions are simply spread in layers, poured into a mould or profiled by means of a trace press, and then subjected, e.g. to contact with a moist atmosphere. In a typical Example (1) a dimethylsiloxane oil, containing 0,15% by weight of SiOH groups and obtained by heating the cyclic tetramer with aqueous KOH-, was mixed with methyltriacetoxysilane in an apparatus fitted with a stirrer, and agitated under an atmosphere of dry nitrogen until a translucent liquid was obtained; a portion of this liquid was cast on a glass plate and formed a film after 5 hours in the ambient air at 20 DEG C. Uses: for sticking various materials together, e.g. silicone rubber, phenol-formaldehyde resins, brickwork, wood and glass; for caulking, coating glass fabrics, protecting supports, covering articles and producing films and moulded articles.