초록 ▼

A method of preparing a thermoplastic elastomer having A blocks and at least one B block, wherein said A blocks are crystalline at temperatures below about 60°C. and said B block(s) is amorphous at temperatures above about -20°C., said A blocks each being polyethers derived from monomers of oxetane

A method of preparing a thermoplastic elastomer having A blocks and at least one B block, wherein said A blocks are crystalline at temperatures below about 60°C. and said B block(s) is amorphous at temperatures above about -20°C., said A blocks each being polyethers derived from monomers of oxetane and its derivatives and/or tetrahydrofuran and its derivatives, the method comprising providing hydroxyl terminated A blocks which are crystalline at temperatures below about 60°C. and separately providing hydroxyl terminated B blocks which are amorphous at temperatures above about -20°C., end-capping said A blocks and said B blocks by separately reacting each of said A blocks and B blocks with a diisocyanate in which one isocyanate moiety is at least about five times as reactive with the terminal hydroxyl groups of each of the blocks as the other isocyanate moiety, whereby the more reactive isocyanate moiety tends to react with terminal hydroxyl groups of the blocks, leaving the less reactive isocyanate moiety free and unreacted, mixing said end-capped A blocks and said end-capped B blocks together at approximately the stoichiometric ratios that they are intended to be present in the thermoplastic elastomer, and reacting said mixture with a linking compound having two isocyanate-reactive groups which are sufficiently unhindered to react with the free isocyanate groups of said end-capped polymer.

대표청구항 ▼

A method of preparing a thermoplastic elastomer having A blocks and at least one B block, wherein said A blocks are crystalline at temperatures below about 60°C. and said B block(s) is amorphous at temperatures above about -20°C., said A blocks each being polyethers derived from monomers of oxetane

A method of preparing a thermoplastic elastomer having A blocks and at least one B block, wherein said A blocks are crystalline at temperatures below about 60°C. and said B block(s) is amorphous at temperatures above about -20°C., said A blocks each being polyethers derived from monomers of oxetane and its derivatives and/or tetrahydrofuran and its derivatives, the method comprising providing hydroxyl terminated A blocks which are crystalline at temperatures below about 60°C. and separately providing hydroxyl terminated B blocks which are amorphous at temperatures above about -20°C., end-capping said A blocks and said B blocks by separately reacting each of said A blocks and B blocks with a diisocyanate in which one isocyanate moiety is at least about five times as reactive with the terminal hydroxyl groups of each of the blocks as the other isocyanate moiety, whereby the more reactive isocyanate moiety tends to react with terminal hydroxyl groups of the blocks, leaving the less reactive isocyanate moiety free and unreacted, mixing said end-capped A blocks and said end-capped B blocks together at approximately the stoichiometric ratios that they are intended to be present in the thermoplastic elastomer, and reacting said mixture with a linking compound having two isocyanate-reactive groups which are sufficiently unhindered to react with the free isocyanate groups of said end-capped polymer.