Method of producing thermoplastic elastomers having alternate crystalline structure such as polyoxetane ABA or star block copolymers by a block linking process
US5516854A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1990 |
| Grant date | May 14, 1996 |
| Priority date | — |
| Expiry date | Jul 27, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G2250/00
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
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.degree. C. and said B block is amorphous at temperatures above about -20.degree. 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 monofunctional hydroxyl terminated A blocks which are crystalline at temperatures below about 60.degree. C. and separately providing di-, tri- or tetrafunctional hydroxyl terminated B blocks which are amorphous at temperatures above about -20.degree. C., end-capping said A blocks by separately reacting said A blocks with a difunctional diisocyanate in which one isocyanate moiety is at least about five times as reactive with the terminal hydroxyl group of the A blocks as the other isocyanate moiety, whereby the more reactive isocyanate moiety tends to react with the terminal hydroxyl group of the A blocks, leaving the less reactive isocyanate moiety free and unreacted, and adding di-, tri- or tetrafunctional B block to the end-capped A blocks at approximately the stoichiometric ra…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.