| 摘要 |
FIELD: polymer production. ^ SUBSTANCE: invention is concerned with a method for preparing prepolymer for use in delivery device for single-component foamed material via polymerization of mixture containing (A) isocyanate components, (B) polyol component containing one or several polyols to impart rigidity to foamed material and (C) low-viscosity component non-reactive toward isocyanate and hydroxyl groups. Disclosed prepolymer preparation process comprises stage of removing free diisocyanate monomer from the prepolymer to a level below 2% after polymerization of mixture containing A, B, and C components or after polymerization of mixture containing A and B components followed by adding C component. Free diisocyanate monomer is removed from prepolymer using elevated temperatures and/or reduced pressures, e.g. by means of thin-layer distillation. Once distillation is completed, prepolymer jointly with commonly used additives, such as cell stabilizers, foaming agents, propellants, and catalysts, is placed in suitable delivery container. ^ EFFECT: increased strength of foamed material and reduced content of diisocyanate monomer therein. ^ 2 cl, 2 tbl, 4 ex |
