Method of making moisture-resistant polyurethane-based pressure-sensitive adhesives
US3940513A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 19, 1974 |
| Grant date | Feb 24, 1976 |
| Priority date | — |
| Expiry date | Feb 19, 1994 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2666/28
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
In U.S. Pat. Nos. 3,437,622 and 3,761,307 and U.S. Pat. application Ser. No. 323,944, filed January 15, 1973 and now abandoned, are disclosed pressure-sensitive adhesives, the required cohesive strength of which is provided by a polyurethane polymer in place of the natural or synthetic rubber of the prior art. However, some of such polyurethane-based adhesives are not highly resistant to moisture unless special procedures are used. For example, they may lose 20 to 75% of their adhesiveness after exposure for 3 days or less to 90% relative humidity at 150.degree.F. This invention discloses means of overcoming this problem by combinations of excluding moisture, adding minor proportions of the reaction-products of hydroxylated elastomers or of hexamethylene tetramine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.