Polyurethane elastomers
AssigneeHuntsman International LLC
InventorsGerhard Jozef Bleys, Alan James Hamilton, Jan Willem Leenslag
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Abstract
A polyisocyanate-based elastomer having a ratio of the storage modulus (E′) at 20° C. and the storage modulus (E′) at 120° C. of between 0.75 and 1.5, a tan δ at 100° C. of less than 0.1 and a maximum value of the tan δ of more than 0.8, the tan δ being the ratio of the loss modulus (E″) and the storage modulus (E′).
Claims17
An elastomer having a ratio of the storage modulus (E′) at 20° C. and the storage modulus (E′) at 120° C. of between 0.75 and 1.5, a tan δ at 100° C. of less than 0.1 and a maximum value of the tan δ of more than 0.8, the tan δ being the ratio of the loss modulus (E″) and the storage modulus (E′), the storage and loss modulus being measured by Dynamic Mechanical Thermal Analysis according to ISO/DIS 6721-5, wherein the elastomer is made from a reaction mixture comprising a polyisocyanate component, a polyol composition, a chain extender and optionally a crosslinking agent wherein the polyisocyanate component contains at least 85% by weight of 4,4′-diphenylmethane diisocyanate or a variant thereof derived from a polyisocyanate composition containing at least 85% by weight of 4,4′-diphenylmethane diisocyanate, the polyol composition comprises at least one polyoxyalkylene polyol containing oxyethylene residues, said polyol composition having an average nominal hydroxyl functionality of from 2 to 4, an average hydroxyl equivalent weight of from 500 to 7000 and an average oxyethylene content of between 50 and 85% by weight, and the chain extender has an average hydroxyl equivalent weight of up to about 250.
A method for the preparation of an elastomer comprising reacting a polyisocyanate component, a polyol composition, a chain extender and optionally a crosslinking agent wherein the polyisocyanate component contains at least 85% by weight of 4,4′-diphenylmethane diisocyanate or a variant thereof derived from a polyisocyanate composition containing at least 85% by weight of 4,4′-diphenylmethane diisocyanate, the polyol composition comprises at least one polyoxyalkylene polyol containing oxyethylene residues, said polyol composition having an average nominal hydroxyl functionality of from 2 to 4, an average hydroxyl equivalent weight of from 500 to 7000 and an average oxyethylene content of between 50 and 85% by weight, and the chain extender has an average hydroxyl equivalent weight of up to about 250;
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- wherein said elastomer has a ratio of the storage modulus (E′) at 20° C. and the storage modulus (E′) at 120° C. of between 0.75 and 1.5, a tan δ at 100° C. of less than 0.1 and a maximum value of the tan δ of more than 0.8, the tan δ being the ratio of the loss modulus (E′) and the storage modulus (E′), the storage and loss modulus being measured by Dynamic Mechanical Thermal Analysis according to ISO/DIS 6721-5.
Dependencies are inferred from the claim text.