| 摘要 |
1344130 Thermosetting acrylic moulding materials and foams thereof FORD MOTOR CO Ltd 21 Dec 1971 [21 Dec 1970] 59306/71 Headings C3C and C3P A thermosetting moulding powder comprises the reaction product of a monoblocked organic diisocyanate, the blocking group of which is liberated at a temperature of from 120‹ to 170‹ C., with hydroxy group-containing graded rubber particles comprising (a) a core of a cross-linked acrylic polymer derived from a major proportion of a monofunctional acrylate (i.e. an acrylate or methacrylate ester containing no reactive groups such as hydroxyl or epoxy groups) and a minor proportion, as cross-linking agent, of an ethylenically unsaturated monomer containing two or three non-conjugated terminal ethylenic groups; (b) an outer shell of a polymer derived from a mixture of an alkyl acrylate or methacrylate (e.g. methyl methacrylate) and one or more other ethylenically unsaturated monomers including a hydroxy acrylate or hydroxymethacrylate monomer; and (c) an intermediate layer of a polymer derived from the monomer components of said core and said shell. The graded rubber particles, preferably of particle size 0À04 to 1 micron, can be obtained as described in Specification 1,332,070. The crosslinking monomer may be a poly(meth)acrylate or divinylbenzene, and the particles may also contain units of (meth)acrylonitrile, styrene or vinyl acetate. The diisocyanate used is preferably an aromatic compound and can be monoblocked with a phenol, t-butyl alcohol or, preferably, caprolactam. The rubber particles and blocked diisocyanate are reacted in a solvent, after which the reaction product is recovered as a dry foam which is then powdered for moulding use. The powdered material, optionally together with another hydroxy-functional material, e.g. ethylene glycol or the unreacted graded rubber particles, can be moulded and cross-linked; useful applications include cover sleeves for flexible cables and conduits, flooring materials and flexible housings. |
