Polyurethane elastomers comprising allophanate modified isocyanates
AssigneeBayer MaterialScience AG
InventorsStephen Harasin, Richard Roesler, Rick Starcher, Carol Kinney, James Garrett
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Abstract
This invention relates to polyurethane elastomers and to a process for their production. These elastomers comprise the reaction product of a polyisocyanate component comprising an allophanate modified (cyclo)aliphatic polyisocyanate which has an NCO group content of about 15 to about 35% or a prepolymer thereof, with an isocyanate-reactive component comprising one or more polyether polyols which is free of amine groups, and a low molecular weight organic compound containing two hydroxyl groups and which is free of amine groups, in the presence of one or more catalysts.
Claims20
A process for the production of a polyurethane elastomer comprising reacting a reaction mixture by a reaction injection molding technique, wherein the reaction mixture comprises:
- (A) a polyisocyanate component comprising (I) an allophanate-modified polyisocyanate having an NCO group content of about 15 to about 35% by weight, and comprising the reaction product of:
- (1) a (cyclo)aliphatic polyisocyanate having an NCO group content of about 25 to about 60% NCO,
- with
- (2) an organic alcohol selected from the group consisting of aliphatic alcohols containing from 1 to 36 carbon atoms, cycloaliphatic alcohols containing from 5 to 24 carbon atoms and aromatic alcohols containing from about 7 to about 12 carbon atoms in which the alcohol group is not directly attached to an aromatic carbon atom;
- with
- (B) an isocyanate-reactive component comprising:
- (1) from about 70 to about 90% by weight, based on 100% by weight of (B), of one or more polyether polyols having a functionality of from about 2 to about 8, a molecular weight of about 1,000 to about 8,000 and is free of amine groups;
- (2) from about 10 to about 30% by weight, based on 100% by weight of (B), of one or more organic compounds having a molecular weight of from about 62 to about 400, having a hydroxyl functionality of 2 to 3, and is free of amine groups,
- in the presence of
- (C) one or more catalysts corresponding to the formula:
- wherein:
- m:
- represents an integer from 3 to 8,
- and
- n:
- represents an integer from 3 to 8;
- and, optionally,
- (D) one or more additives;
- wherein the relative amounts of (A) and (B) are such that the isocyanate index ranges from about 90 to about 120.
A polyurethane elastomer comprising the reaction product of:
- (A) a polyisocyanate component comprising (I) an allophanate-modified polyisocyanate having an NCO group content of about 15 to about 35% by weight, and comprising the reaction product of:
- (1) a (cyclo)aliphatic polyisocyanate having an NCO group content of about 25 to about 60% NCO,
- with
- (2) an organic alcohol selected from the group consisting of aliphatic alcohols containing from 1 to 36 carbon atoms, cycloaliphatic alcohols containing from 5 to 24 carbon atoms and aromatic alcohols containing from about 7 to about 12 carbon atoms in which the alcohol group is not directly attached to an aromatic carbon atom;
- with
- (B) an isocyanate-reactive component comprising:
- (1) from about 70 to about 90% by weight, based on 100% by weight of (B), of one or more polyether polyols having a functionality of from about 2 to about 8, a molecular weight of about 1,000 to about 8,000 and is free of amine groups;
- (2) from about 10 to about 30% by weight, based on 100% by weight of (B), of one or more organic compounds having a molecular weight of from about 62 to about 400, having a hydroxyl functionality of 2 to 3, and is free of amine groups,
- in the presence of
- (C) one or more catalysts corresponding to the formula:
- wherein:
- m:
- represents an integer from 3 to 8,
- and
- n:
- represents an integer from 3 to 8;
- and, optionally,
- (D) one or more additives;
- wherein the relative amounts of (A) and (B) are such that the isocyanate index ranges from about 90 to about 120.
Dependencies are inferred from the claim text.