Plastic crayon
US5055498A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1990 |
| Grant date | Oct 8, 1991 |
| Priority date | — |
| Expiry date | Jun 19, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09D13/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The solid marking composition of the invention includes from about 15% up to about 50% by weight of a polyethylene resin component having a specific gravity in the range of from about 0.95 up to about 0.96. In addition, the composition of the invention includes from about 20% up to about 55% by weight of a compatible plasticizer, and from about 3% up to about 20% by weight active material of a pigment. Optionally, the composition may include a pigment dispersing agent, such as a fatty acid. Further additives which may advantageously employed include extenders or fillers, oxidation stabilizers, UV stabilizers, and mold release agents. The composition of the invention is fabricated into marking instruments having unexpectedly improved eraseability, ease of application, barrel breaking strength, and tip breaking strength, while eliminating bloom entirely.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.