Pencil for writing or colouring
US10316208B2 · kind B2 · utility
2Cited by
5References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 14, 2015 |
| Grant date | Jun 11, 2019 |
| Priority date | — |
| Expiry date | May 25, 2036 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB43K19/18
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
The present invention thus relates to a writing or color pencil comprising the following 3 layers obtained by coextrusion a polyolefin-based non-expanded lead, a non-expanded protective intermediate layer surrounding the lead and comprising a mixture of polystyrene and EVA, and an expanded synthetic wood material based on a styrene polymer surrounding the protective intermediate layer, the protective intermediate layer thickness/lead radius ratio being between 0.05 and 0.17, advantageously between 0.07 and 0.15.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.