초록 ▼

Polydiene polyurethanes having high tear strength are obtained by using polydiene glycols, prepared with use of lithium-based catalyst, having a number average molecular weight of 1,000 to 5,000 and functionality of 1.8 -2.1, diisocyanates and chain-extending agents, and by controlling chemical cros

Polydiene polyurethanes having high tear strength are obtained by using polydiene glycols, prepared with use of lithium-based catalyst, having a number average molecular weight of 1,000 to 5,000 and functionality of 1.8 -2.1, diisocyanates and chain-extending agents, and by controlling chemical cross-link density being 4 ×10-5 mole/cc and less. When the chemical cross-link density is within the above range, elongation and tensile strength in addition to tear strength of the polyurethane are improved significantly. Furthermore, when 10 -50 parts by weight of the specified carbon black are added to 100 parts by weight of the mixture of the prepolymer, the chain-extending agent and the additive prior to curing the prepolymer, these mechanical properties of the polyurethane are improved further.

대표청구항 ▼

A process for preparing a polydiene polyurethane having high tear strength, which process comprises reacting a. a polydiene glycol prepared with use of a dilithio compound as a catalyst, and having a functionality of from 1.8 to 2.1 and a number average molecular weight of from 1,000 to 5,000, the r

A process for preparing a polydiene polyurethane having high tear strength, which process comprises reacting a. a polydiene glycol prepared with use of a dilithio compound as a catalyst, and having a functionality of from 1.8 to 2.1 and a number average molecular weight of from 1,000 to 5,000, the residual lithium content being below 30 ppm, b. a diisocyanate compound, and c. a chain-extending agent selected from diamine and diol compounds by the prepolymer method, the equivalent ratio of the isocyanate groups in said polydiene glycol being 1.5 to 3.0, the equivalent ratio of active hydrogens in said chain-extending agent to isocyanate groups in said prepolymer being 0.8 to 1.1, and the curing temperature being 50 to 140°C. the polydiene polyurethane so obtained having a chemical cross-link density of 4 ×10-5 mole/cc or less.