PROCESS FOR PREPARING CARBIDE-FORMALDEHYDE PLASTIC FOAM Russian patent published in 1997 - IPC

FIELD: preparation of polymeric materials, more particularly carbide-formaldehyde plastic foams used as thermoinsulating materials in construction and for improvement of structure of soils. SUBSTANCE: claimed process comprises adding carbide-formaldehyde resin at urea to formaldehyde resin molar ratio of 1.00:(1.15-1.20) adding carbide-formaldehyde resin at urea to formaldehyde resin molar ratio of 1.00:(1.5-1.65) at weight ratio of 1.0: (0.5-4.0), dispersing mixture of resins and mixing said mixture with foamed solution of foaming hardening agent. Plastic foam for arrangement of flowers is prepared with weight ratio of resins maintained at 1.00:(3.0-4.0). Acid resistant dye is added to foaming-hardening agent solution in amount of 0.5-0.7 g per 100 g of solution, and plastic foam is additionally treated with aqueous solution at 50-60 C for 10-30 minutes. Said aqueous solution contains nitric or oxalic acid, salt in amount of 28-50 g/l, and glycol or water soluble polyglycol in amount of 25-50 g/l. EFFECT: lower toxicity with constant quality properties of the plastic foam, and wider use of carbamide-formaldehyde resins. 1 tbl