Process for preparing foamed solids using two or more azo compounds
US4101464A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1976 |
| Grant date | Jul 18, 1978 |
| Priority date | — |
| Expiry date | Sep 16, 1996 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J9/102
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Cellular polymeric solids are made by mixing an acidulous or acidic polymerizable medium that is polymerizable and/or cross-linkable by a free radical mechanism (e.g. an unsaturated polyester) with an effective amount of two or more acid sensitive mono- or poly-azo compounds containing the group: ##STR1## wherein Y is an acid sensitive group (e.g. Cl, OH, --OCN, --NCO) which in the presence of an acidulous or acidic polymerizable medium causes sufficient decompsition of the azo compound that gas is released in the medium and during the decomposition the mono- or poly- azo compound promotes polymerization and/or cross-linking of the medium to provide a matrix that is sufficiently polymerized and/or cross-linked that the generated gases cause the matrix to expand, each of the remaining valences being satisfied by an organic radical; provided that any carbon atom that is directly linked to an azo nitrogen, except that of a carbonyl group, has at least two of its remaining three valences satisfied by a carbon to carbon bond or a carbon to hydrogen bond. Preferably, the mixture contains at least two such azo compounds having appreciably different sensitivity to decomposition by acid. Th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.