Patent GB-872147-A (GB)
Title: Heat-hardenable compositions composed of polyvinyl chloride, epoxy resin and hardening agent
IPC: C08L27/06
Filed: 1958-03-03
Abstract: Heat-hardenable compositions, which are paste-like to liquid at room temperature, comprise (i) powdered P.V.C. or paste-forming co-polymers thereof (ii) an epoxy resin, and (iii) a hardener for (ii) which is a polycarboxylic anhydride and is capable of forming with the epoxy resin, at least upon being so heated with the resin as to avoid gelatinization, and being subsequently cooled, a mixture that is a pourable liquid at room temperature.  Components specified are: (i) P.V.C., and co-polymers of vinyl chloride with vinylidene chloride, vinyl ethers, or vinyl acetate, and in Examples (7) and (8) a mixture of P.V.C. with a copolymer of vinyl and vinylidene chlorides; (ii), which are preferably liquid, polyglycidyl ethers of resorcinol, hydroquinone, bisphenol A, phenol-formaldehyde resins, ethylene glycol or glycerine, polyglycidyl esters of phthalic or terephthalic acid, and butadiene dioxide; (iii) methyl-endomethylene tetrahydrophthalic, dodecenyl-succinic, or hexahydrophthalic anhydrides, or mixtures of anhydrides, the mixtures being liquid at room temperature after their components have been melted together and cooled, e.g. a mixture of hexahydrophthalic with tetrahydrophthalic and/or phthalic, and a mixture of hexachloroendomethylene tetrahydrophthalic with hexahydrophthalic or with methyl endomethylene tetrahydrophthalic with or without endomethylene tetrahydrophthalic.  Other additives specified are: accelerators (2,4,6-tris-(dimethylaminomethyl)-phenol and BF3), diluents (cresyl glycide), stabilizers (Pb stearate, carbonate or phosphite), dioctyl phthalate, fillers, e.g. glass fibres, mica, quartz meal, cellulose, kaolin and metal powder, and blowing agents (see Group V).  All the various components may be mixed in various orders.  Uses: Coating (steel or glass), laminates, printing pastes, casting, impregnating, embedding, foils, and foamed articles. Specification 872,148 is referred to.ALSO:Foamed materials may be produced by incorporating a blowing agent in a heat-hardenable composition which is paste-like to liquid at room temperature and which comprises (i) a powdered P.V.C. or a paste-forming co-polymer thereof, (ii) an epoxy resin, and (iii) a hardener for (ii) which is a polycarboxylic anhydride and is capable of forming in the epoxy resin, at least upon being so heated with the resin as to avoid gelatiniation, and being subsequently cooled, a mixture that is a pourable liquid at room temperature. Especially suitable is a 2-stage blowing method in which in the first stage a homogeneous paste is gelatinized in a closed mould at about 150 degree under pressure, the moulded article is removed from the mould after cooling, whereupon an initial expansion takes place, and then in the same stage the final expansion and hardening are brought about at 100 DEG C. without a mould.  In Examples (9), (10) and (11) this process is carried out using compositions comprising : pulverulent P.V.C., a liquid epoxy resin, cresylglycide, Pb stearate, ether hexalhydrophthalic anhydride or a mixture of hexahydro-, tetrahydro- and phthalic anhydrides, and, as blowing agent, either azodiisobutyronitrile or azo-hexahydrobenzonitrile.  The quantities of the various components are varied to give products of different densities and all sizes; the cells are apparently closed.  The dimensional stability of the products may be increased by adding a plasticizer such as dioctyl phthalate.  Constituents listed include: (i) co-polymers of vinyl chloride with vinylidene chloride, vinyl ethers or vinyl acetate; (ii) polyglycidyl ethers of phenols, phenol-formaldehyde resins, or alcohols, polyglycidyl esters, and butadiene dioxide; and (iii) dodecenyl succinic anhydride and various carboxylic anhydrides including a chlorinated one, which may be used alone or in mixtures (see Group IV(a)). Specifications 872,148 is referred to.