POLYURETHANE COMPOSITION FOR ARTICLES WITH INCREASED FROST RESISTANCE AND METHOD FOR PRODUCTION THEREOF Russian patent published in 2021 - IPC C08L75/04 C08L75/08 C08G18/10 C08G18/48 B29C39/00 

FIELD: polymers.

SUBSTANCE: present invention relates to a group of inventions: a polyurethane composition for articles with increased frost resistance and a method for manufacturing a polyurethane composition for articles with increased frost resistance. The composition comprises the components in a ratio, molar fractions: polyurethane prepolymer based on mixtures of polyethers with a molecular weight of 1,000 to 2,000 - 1.0; mixture of 2,4- and 2,6-toluylenediisocyanates - 1.9 to 2.2, amine hardener - 0.85 to 0.95. The content of isocyanate groups in the composition is 3.3÷5.7 wt.% at a stoichiometric concentration of the amine hardener of 85÷95 wt.%. The amine hardener constitutes a eutectic mixture of bi-, tri- and greater functionality amines. The method includes three stages: first stage - the raw materials, polyethers with a molecular weight of 1,000 to 2,000 are heated until complete melting, followed by loading into a prepolymer synthesis reactor, wherein, prior to the synthesis of the prepolymer, the polyethers are dried under a vacuum at a temperature of 80÷95°C until a moisture content of no more than 0.08 wt.% at Pres = 10÷20 mm Hg is reached, followed by cooling the polyethers to a temperature of 50÷60°C, then the calculated amount of 2,4- and 2,6-toluylenediisocyanate with a certain isocyanate index is loaded into the cooled mixture of polyethers with a working stirrer in two or three passes; second stage - synthesis of the prepolymer under a vacuum (Pres = 10÷20 mm Hg) at a temperature of 80÷85°C for 30÷40 minutes, controlling the end of the reaction by sampling for the content of NCO groups; third stage - the hardener heated to 85°C is introduced into the resulting prepolymer with heavy stirring, wherein the stoichiometric concentration of the amine hardener can amount to 85-95 wt.%.

EFFECT: production of a polyurethane composition with a high level of physical and mechanical properties: increased frost resistance, wear resistance, resistance to cyclic loads, low indicators of water absorption and residual deformation, and articles made thereof are suitable for operation under heavy loads, in operating conditions with a large temperature difference, during work in an aggressive environment.

7 cl, 1 tbl, 6 ex