Plastic pencils
US4063828A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1975 |
| Grant date | Dec 20, 1977 |
| Priority date | — |
| Expiry date | Sep 16, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31913
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Plastic pencils comprising a writing core, a porous casing to enclose said writing core, and a coating which is coated on the surface of said porous casing, said casing being a homogeneous unitary mixture composed of 100 parts by weight of atactic polystyrene, 10-40 parts by weight of polyethylene, 10-55 parts by weight of glass fibers and the required amount of coloring agent and having sharpenability comparable to that of incense cedar and a flexural modulus in excess of 30,000 kg/cm.sup.2, and said coating being a homogeneous unitary mixture composed of 100 parts by weight of atactic polystyrene, 5-50 parts by weight of polyolefin and a required amount of a coloring agent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.