Patent ID: 6770681
Filing Date: 2004-08-03
Classification: C08J

Abstract:
A suspension for use in forming a foamable copolymer resin, the suspension comprising the following components: methyl methacrylate and styrene monomers, an initiator comprising an organic peroxide selected from the group consisting of benzoyl peroxide and tert-butyl perbenzoate, a foaming agent selected from the group consisting of pentane, isohexane and petroleum ether, a modifying aid comprising divinyl benzene or ethylene glycol dimethecrylate and a compound selected from the group consisting of C8-C12-alkyl mercaptan, carbon tetrabromide and carbon tetrachloride, a dispersant comprising a cellulose ether selected from the group consisting of hydroxy ethyl cellulose and hydroxylpropyl cellulose ether, and deionized water, the components being present in the suspension in parts by weight as follows:a) 40 to 49 of the methyl methacrylate monomer, 51 to 60 of the styrene monomer, 180 to 225 of the deionized water, 0.25 to 0.55 of the dispersant, 10 to 14 of the foaming agent, 0.35 to 0.75 of the initiator and 0.2 to 0.5 of the modifying aid; or b) 91 to 95 of the methyl methacrylate monomer, 5 to 9 of the styrene monomer, 230 to 270 of the deionized water, 0.4 to 0.6 of the dispersant, 13 to 15 of the foaming agent, 0.25 to 0.65 of the initiator and 0.5 to 1.0 of the modifying aid; or c) 70 of the methyl methacrylate monomer, 30 of the styrene monomer, 180 to 220 of the deionized water, 0.3 to 0.6 of the dispersant, 8 to 15 of the foaming agent, 0.3 to 0.8 of the initiator and 0.35 to 0.60 of the modifying aid.