Moisture curable polyurethane systems
US4038239A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 19, 1975 |
| Grant date | Jul 26, 1977 |
| Priority date | — |
| Expiry date | Aug 19, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/0885
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The disclosed process for making a high % solids, one-part, curable, essentially flowable or pumpable, high equivalent weight polyurethane (i.e., polyol-polyisocyanate adduct) prepolymer composition involves de-watering the polyol component of the reaction mixture with an alkaline earth metal oxide, preferably calcium oxide; adding the minimum acceptable level of catalyst for the NCO/polyol reaction; exothermically reacting a partially hindered aliphatic polyisocyanate such as isophorone diisocyanate (IPDI) and a partially hindered aromatic polyisocyanate such as 2,4-tolylene diisocyanate seriatim, so that at least about one-fourth of the IPDI reacts before the 2,4-TDI is added; and then adding more catalyst for the curing (e.g. moisture cure) reaction. Careful control over the amounts and selection of raw materials, proper selection of sequences of addition of these amounts and materials, careful de-watering of the reaction mixture, and proper adjustment or selection of isocyanate functionality minimizes random and undesired reactions and side reactions (e.g. chain extension) during prepolymer formation and insures good elastomeric properties in the ultimately cured product. As a …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.