TH34413A - Moisture-cured elastomer and heat cured of polyurethane. And polyurethane / urea Where physical properties were improved - Google Patents

Abstract

DC60 (10/02/42) Elastomers with improved physical properties, especially strength, elasticity, tensile strength, and compression set, can be prepared by chain extension or moisture curing of isocyanate terminates. Prepolymers prepared from polyol compositions consisting of high molecular weight polyoxypropylene, low unsaturated diols, and low molecular weight diols are useful for applications such as rollers and other applications where physical properties are critical. Elastomers with improved physical properties, especially strength, elasticity, tensile strength, and compression set, can be prepared by chain extension or moisture curing of isocyanate terminates. Prepolymers prepared from polyol compositions consisting of high molecular weight polyoxypropylene, low unsaturated diols, and low molecular weight diols are useful for applications such as rollers and other applications where physical properties are critical.

Claims (13)

1. Isocyanate terminate prepolymers or quasi-prepolymers, which contain an excess of stoichiometric reaction products of di- or polyisocyanates greater than toluene diisocyanates in which the polyol composition consists of: ai) 1 or more 1 high molecular weight polyoxypropylene diols with an unsaturation of less than 0.02 meq/g and a molecular weight greater than 2000 Daltons; and aii) 1 or more 1 low molecular weight diols with a molecular weight less than 400 Daltons, where the hydroxyl number of such polyols is between 50 and 200. 2. Prepolymers or quasi-prepolymers conforming to Patent 1, where such prepolymers have an NCO group capacity of 2% by weight to 12% by weight. 3. Prepolymer or quasi-prepolymer conforming to claim 1 or 2 when the polyoxypropylene diol has less than 0.015 meq. grams of unsaturated polyoxypropylene diol. 4. Prepolymers or quasi-prepolymers conforming to any one of the above claims when such polyoxypropylene diol has a molecular weight between 3000 Daltons and 800 Daltons. 5. Prepolymers or quasi-prepolymers conforming to one of the above claims when at least 1 of such low molecular weight diols has a molecular weight not greater than 200 Daltons. 6. Prepolymers or quasi-prepolymers conforming to one of the above claims are selected from a pool consisting of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, diethylene glycol, tripropylene glycol, 2-methyl-1,3-propanediol and mixtures thereof. 7. Prepolymers or quasi-prepolymers as per the aforementioned claims when the hydroxyl number of the polyol component is approximately between 75 and 150. 8. A polyurethane or polyurethane/urea elastomer recomposed of a reaction product of a prepolymer conforming to one of the above claims, and b) a chain extender with an isocyanate index of 85 to 115. 9. A polyurethane or polyurethane/urea elastomer that has been repeatedly cured by moisture consists of a prepolymer reaction product conforming to one of the claims 1 through 7 above, and water. 10. An elastomer compliant with claim 8 when such chain extender contains diol or diamine. 11. An elastomer conforming to claim 8 or 10 when such chain extender is selected from a group consisting of 1,4-butanediol, ethylene glycol neopentyl glycol, 2-methyl-1,3-propanediol, 4,4''-methylenebis(3-chloro-2,6-diethylaniline). 12. Microcellular elastomer that complies with any of the claims 8 through 11. 13. Methods for the preparation of polyurethane or polyurethane/urea elastomers in which the method involves the reaction of: a) an isocyanate terminate prepolymer or quasi-prepolymer containing an excess of stoichiometric reaction products of di- or polyisocyanate more than toluene diisocyanate in which the polyol composition consists of: ai) one or more high molecular weight polyoxypropylene diols with an unsaturation of less than 0.02 meq/g and a molecular weight greater than 2000 daltons; and aii) one or more low molecular weight diols with a molecular weight less than 400 daltons, where the hydroxyl number of such polyol composition is from 50 to 200 (Clause 15, page 3, Figure).