| abstract |
A rubber-impregnated plastic foam is obtained by soaking a preformed body of foamed polyurethane or polyvinyl plastic in a bath of a rubber latex composition or spraying or brushing the foamed plastic with the latex composition which contains a sulphur vulcanizing agent comprising 1 to 3% of sulphur based on the dry weight of the rubber component, the latex composition being introduced into the foamed plastic in an amount such that the weight ratio of rubber to plastic in the composite material is within the range from 2:1 to 5:1, drying the latex -soaked material and vulcanizing at a temperature of at least 100 DEG C. for not more than 70 minutes to establish cross-linking bridges of sulphur between the rubber component and the plastic component. The latex may be derived from natural rubber or synthetic rubbers based on butadiene, styrenebutadiene, isoprene and/or chloroprene. An anticoagulant such as sodium lauryl sulphate may be incorporated in the latex or used to impregnate the plastic prior to latex treatment. Polyurethane plastics may be exposed to the action of difluorodichloromethane or monofluorotrichloromethane before soaking, e.g. in the foaming stage. Fire retarding agents such as sodium, potassium or ammonium phosphates may be added. Products with unimpregnated cores may be prepared.ALSO:A fire-proofed plastic foam is obtained by soaking a preformed body of foamed polyurethane or polyvinyl plastic in a bath of a rubber latex composition or spraying or brushing the foamed plastic with the latex composition which contains a sulphur vulcanising agent comprising 1 to 3% of sulphur based on the dry weight of the rubber component, the latex composition being introduced into the foamed plastic in an amount such that the weight ratio of rubber to plastic in the composite material is within the range from 2 : 1 to 5 : 1, drying the latex-soaked material and vulcanising at a temperature of at least 100 DEG C. for not more than 70 minutes to establish cross-linking bridges of of sulphur between the rubber component and the plastic component. The latex may be derived from natural rubber or synthetic rubbers based on butadiene, styrene-butadiene, isoprene and/or chloroprene. An anticoagulant such as sodium lauryl sulphate may be incorporated in the latex or used to impregnate the plastic prior to latex treatment. Polyurethane plastics may be exposed to the action of difluorodichloromethane or monofluorotrichloromethane before soaking, e.g. in the foaming stage. Fire retarding agents such as sodium, potassium or ammonium phosphates may be added. Products with unimpregnated cores may be prepared. |