SOLID POLYURETHANE ELASTOMERS, HAVING LOW SHRINKAGE OF DIMENSIONS Russian patent published in 2011 - IPC C08G18/10 C08G18/40 C08G18/48 

FIELD: chemistry.

SUBSTANCE: invention relates to a solid polyurethane elastomer having low shrinkage, used in production of cast polyurethane articles via reaction injection moulding, as well as a method of producing said elastomer. Said elastomer contains a product of reaction (A) of polyisocyanate prepolymer containing 10-30% isocyanate groups and (B) a component which is reactive towards isocyanate in the presence of (C) one or more catalysts. Component (A) contains a product of reaction between polyisocyanate, having isocyanate functionality from approximately 2 to approximately 2.5, and a component which is reactive towards isocyanate, having molecular weight less than 1000 and hydroxyl functionality from approximately 2 to approximately 4. Component (B) contains the following (in wt %) per 100% total weight of (B)(1), (B)(2) and (B)(3): (1) from approximately 80 to approximately 90 of at least one component reactive towards isocyanate, having functionality from approximately 2 to approximately 3, hydroxyl number from approximately 28 to approximately 35, molecular weight from approximately 4000 to approximately 6000, and containing less than 15 wt % per 100% weight of alkylene oxide groups present in (B)(1), ethylene oxide, completely present as terminal groups, and in which the residue of alkylene oxide groups present in (B)(1) is propylene oxide groups: (2) from approximately 10 to approximately 20 chain extender, having functionality of approximately 2 and molecular weight from approximately 60 to less than approximately 250, where the chain extender is selected from a group consisting of ethylene glycol, 1,4-butane diol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol or mixtures thereof, and (3) from 2 to approximately 5 components reactive towards isocyanate, having hydroxyl functionality from approximately 3 to approximately 4, hydroxyl number from approximately 400 to approximately 850, molecular weight from approximately 200 to approximately 400, and containing a product of reaction of a compound, which contains at least two amine groups, with alkylene oxide. Components (A) and (B) react in a closed mould through reaction injection moulding with isocyanate index from approximately 70 to approximately 130.

EFFECT: method reduces shrinkage of solid elastomers without adding special additives, such as organic filling substances or acid additives.

10 cl, 5 tbl