Polyurea-polyurethane from a mixture of a polyol, an aromatic diamine, and an isocyanate-terminated prepolymer
US4374210A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 18, 1981 |
| Grant date | Feb 15, 1983 |
| Priority date | — |
| Expiry date | Sep 18, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G2120/00
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The use of certain prepolymers of 4,4'-methylenebis(phenyl isocyanate), in place of the latter diisocyanate itself in the preparation of polyurethane-polyureas using aromatic diamine extenders, has a number of advantages particularly when the compositions are prepared by reaction injection molding techniques using two streams of reactants. The principal advantages are (i) a useful increase in gel time and (ii) a ratio of amounts of the two reactant streams which more nearly approaches 1:1. This latter factor not only improves the efficiency of mixing of the components in the mixing head but, together with the longer gel time, significantly increases the output of mixed reactants per unit of time. The prepolymers of 4,4'-methylenebis(phenyl isocyanate) employed to achieve the above results are those derived from polyoxyethylene polyoxypropylene polyether diols and triols (MW=1000-10,000), polytetramethylene glycols (MW=600-5,000) and polyester diols and triols (MW=500-8,000).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.