HETEROGENEOUS POLYMER MIXTURE

1299742 Polymerizing within the pores of a foamed polymer FARBENFABRIKEN BAYER AG 18 Nov 1969 [29 Nov 1968] 56270/69 Heading C3P [Also in Division B2] A heterogeneous polymer mixture of interpenetrating coherent phases comprises a first polymer in the form of a foam, and a second polymer filling the pores of at least a part of the foam of the first polymer, the first and second polymers each forming a coherent phase, and the second polymer having been polymerized within the pores of the first polymer in the absence of compression. The foam is preferably open pored to the extent of 5-100% by volume. The second polymer may be made from a mixture of monomers, which may be in solution. The foam may be of, for example, a polyamide, a polyolefin, a urea-formaldehyde resin, a phenolformaldehyde resin, a polyester-urethane resin a polyether-urethane resin, a cured unsaturated polyester resin, polyvinylchloride, polystyrene or a polyurethane. The second resin may be, for example an epoxy resin, a polymer of a vinyl compound such as styrene, or a mixture of styrene with comonomers such as fumaric acid and maleic acid esters, acrylic and methacrylic esters, or a mixture of styrene with an unsaturated polyester, a polyurethane, a lactam polymer, or a polyamide. In the examples (1) and (2) a polyamide foam is impregnated with a styrene/diethylfumarate mixture which is polymerized; (3) a maleic anhydride/phthalic anhydride/propylene glycol unsaturated polyester and styrene are polymerized in a phenolformaldehyde resin foam; (4), as in (3) but using a urea-formaldehyde resin foam and (5), as in (3) but using a polyester-urethane foam.