Method of producing thermoplastic elastomers having alternate crystalline structure for use as binders in high-energy compositions
US4806613A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 29, 1988 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Mar 29, 2008 |
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(s) 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 PA0 providing hydroxyl terminated A blocks which are crystalline at temperatures below about 60.degree. C. and separately providing hydroxyl terminated B blocks which are amorphous at temperatures above about -20.degree. C., PA0 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, PA0 mixing said end-capped A blocks and said end-capped B blocks together at approximately the stoichiometric ratios th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.