Compositions, processes, and writing elements employing resins of the thermosetting type
US4371632A · kind A · utility
9Cited by
41References
31Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1981 |
| Grant date | Feb 1, 1983 |
| Priority date | — |
| Expiry date | Apr 24, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09D13/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A "cold-processed" thermoset plastic pencil lead is produced by extruding a composition formed by blending a mixture of a marking material, a phenolic novolac resin, a hardening agent, a plasticizer, and a lubricant. Blending, billeting, and extruding operations are performed at material temperatures that, in general, do not exceed about 200.degree. F. The extrudate is cured at higher temperatures of, for example, 260.degree. F. to 325.degree. F.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.