GB788074A - Improvements in or relating to silicon-containing resinous products and compositionscontaining the same - Google Patents

Abstract

Resinous products are obtained by heating a composition comprising a hydroxy-containing polyepoxide, or a hydroxy-containing polyepoxide derivative which is free of epoxy groups, and an organo-silicon compound having a halogen atom and/or an alkoxy radical attached directly to a silicon atom and not containing a hydrogen atom reactive with epoxy groups, except that in the case of the polyepoxide derivative the silicon compound may alternatively contain a hydroxyl group attached to a silicon atom. Examples of hydroxy-containing epoxides are 4,41 - bis - (2 - hydroxy - 3,4 - epoxybutoxy) diphenyldimethylmethane, 2,3 - bis - (2 - hydroxy-3,4 - epoxybutoxy) benzene, 1,4 - bis - (2-hydroxy - 4,5 - epoxypentoxy) benzene and 1,2,3,4 - tetrakis (2 - hydroxy - 3,4 - epoxybutoxy) butane; glycidyl polyethers of polyhydric phenols, prepared from halohydrins and a polyhydric phenol, particularly bis-phenol-A; glycidyl polyethers similarly prepared from polyhydric alcohols having a secondary OH group; polyethers prepared from a polyhydric phenol or alcohol with a polyepoxide; and hydroxy-containing polymers and copolymers of epoxy-containing unsaturated monomers which have been polymerized in the absence of an alkaline or acidic catalyst and then treated so as to have part of the epoxy groups opened to form hydroxyl groups. Many examples are given of all these epoxides. The derivatives which are free of epoxy groups are prepared by reacting with compounds having an active hydrogen atom, e.g. acids, amines, amides, mercaptans, hydrogen sulphide, alcohols and acetylene derivatives, including those described in Specifications 705,786 and 730,670. The preferred derivatives are polyesters in which the acids used are unsaturated fatty acids containing at least 10 carbon atoms and having an iodine value of at least 110, particularly those derived from natural oils of which many are specified. Examples describe the preparation of Polyesters B and D from glycidyl polyethers of bisphenol-A and linseed oil fatty acids, Polyester F by substituting soybean fatty acid, and Polyester G, using dehydrated castor oil acids. Copolymers of these esters with styrene as described in Specification 705,434 may also be used. The organo-silicon compounds include mono- and poly-silanes and siloxanes, e.g. compounds of the formula RaSiXb, where X is halogen, hydroxy or alkoxy, R is a hydrocarbon including unsaturated, aliphatic and aromatic and substituted hydrocarbon radical, aryloxy, alkaryloxy or aralkoxy radical, and a and b are from 1 to 3; silanes of the formula: <FORM:0788074/IV (a)/1> where R is a hydrocarbon radical, at least one X is a halogen, hydroxy or alkoxy radical and R1 is a divalent organic radical; siloxanes of the formula: <FORM:0788074/IV (a)/2> where at least one R is a halogen, hydroxy or alkoxy radical and the others may be hydrocarbon or hydrocarbyloxy radicals; and silicon esters of the formula R(COOR1SiX3)n, where R is a carboxylic acid residue, R1 is a hydrocarbon or oxa-hydrocarbon radical, one X is halogen, hydroxy or alkoxy, and the others are hydrocarbon, or hydrocarbyloxy radicals. The reaction between the silicon compound and the epoxy compound or derivative may be in the presence of absence of catalysts, solvents and acid-binders, and temperatures of 50-250 DEG C. are normally used. The products are viscousliquid to solid resins and are useful as coating, impregnating and adhesive compositions and for potting and casting in electrical apparatus. For coating purposes, they may be combined with a solvent, curing agent or drier and with other film-forming materials, e.g. phenol-aldehyde resins. They may be cured by various means; e.g. the polyester products prepared from the unsaturated polyesters may be air cured in the presence of driers; those having hydroxyl groups may be cured by reaction with polyisocyanates, urea-formaldehyde resins or polycarboxylic acids; those having amine groups may be cured by reaction with polyepoxides, polycarboxylic acids or phenols; and those having mercapto groups by reaction with polyepoxides, metal oxides and peroxides. Other curing agents are ethylene diamine and phosphoric acid. Examples are given, the silicon compounds used being (1) and (2) trimethyl chlorosilane, (3) and (4) diphenyl silanediol, (5) dimethyldiethoxysilane, (6) trimethylethoxysilane, (7) and (8) a methoxy methylphenyl poly sloxane, and (9) dimethyl triphenyl trimethoxy trisiloxane; and the epoxy derivatives being the Polyesters B, D, F and G referred to above and various glycidyl polyethers of bis-phenol-A. Specifications 737,614 and 760,309 also are referred to.