Verfahren zum Herstellen von klebrige Stoffe abweisenden UEberzuegen

摘要

1,228,194. Polysiloxane coating. WACKERCHEMIE G.m.b.H. 10 July, 1968 [14 Feb., 1968], No. 32824/68. Heading B2E. [Also in Division C3] Coatings which repel tacky substances are produced by applying to a substrate a coating of a solution of a composition comprising 80 to 95% by weight of a diorgano polysiloxane having end groups capable of reacting with an amino-substituted silicon compound and 5 to 20% by weight of a cross-linking aminosubstituted silicon compound containing at least 3 hydrolysable groups in the molecule in a volatile organic solvent that is free from water and is inert to SiN bonds, at least at ambient temperature and curing the coating by heating it to 80‹ to 200‹C in the presence of steam. The substrate may be paper, e.g. imitation parchment, parchment, kraft or silk paper, metals such as aluminium foils and organic plastics, e.g. polyamides or regenerated cellulose, or cardboard. The diorgano polysiloxanes which may be used are those of formula: (in which R is a monovalent optionally substituted hydrocarbon radical, x has an average value of 0.99 to 1.01, y has an average value of 1.99 to 2.01, the sum of x+y is 3, and n is an integer having a value of 10 to 10,000). The hydroxyl groups may be at least partially replaced by other reactive end groups, e.g. radicals of formula R"HN-, where R" is optionally substituted hydrocarbon, alkoxy or alkoxyalkoxy radical. The diorgano polysiloxanes may be homopolymers, mixtures of various homopolymers, copolymers or mixtures of various copolymers. Preferred crosslinking amino-substituted silicone are aminosilanes of formula: (in which R is as hereinbefore defined, R1 is a monovalent hydrocarbon radical, p is 0 or 1, m is 0, 1 or 2. Further examples of crosslinking amino-substituted silicone compounds are: silazanes of formula: (H m R1 2-m N) 2 SiR" (NHSiR"NH m R1 2-m ) n NHSiR" (NH m R1 2-m ) 2 (in which R" is as R or a 1-4C alkoxy or 3-6 C alkoxyalkoxy; n' is 0 or an integer; compounds of formula: R'' r SiZ 4-r (in which Z is aminoalkoxy; r is 0, 1, 2 or 3); and com- O pounds of formula: R" r Si(NR"'CR"') 4-r (in which R"' is as R' or is H). The compositions can be applied by dipping, brushing, pouring, spraying or rolling. The process is particularly suitable for the production of release backings and blanket papers for self-adhesive tapes and self-adhesive films, the coating of the back of self-adhesive tapes and films, of release papers such as are used in the preparation of laminates from epoxy resins and glass fibre fabrics, for the preparation of packaging material for tacky foodstuffs such as meat, and other tacky substances such as asphalt, resins, tar and photographic films.