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US 12,545,047 B2Granted
Writing instrument part, method for manufacturing writing instrument part, and writing instrument
AssigneeMitsubishi Pencil Company, Limited
InventorsKiyoshi Fujisawa, Ryota Kubo
Life of this patent
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Abstract
A writing instrument part that improves the releasability of a core pin is provided. In a writing instrument part by the insert molding method in which a wooden barrel material made of natural wood flour and a water-soluble resin binder is injected into a mold, the wooden barrel material and a core pin having a paper straw inserted therein are integrated, and a two-layer structure having a paper straw layer as an inner layer and a wooden barrel layer as an outer layer is formed.
Claims6
A method of manufacturing a writing instrument part, comprising the steps of:
- forming a space having the shape of a writing instrument part by setting a core pin to which a paper straw is attached in a mold;
- injecting a wooden barrel material composed of wood flour and a binder which is a water-soluble resin into the space from a mold spout provided in the mold;
- producing a first molded article in a state in which the wooden barrel material and the core pin are integrally formed by insert molding by removing the mold after injection;
- and
- obtaining a writing instrument part having a two-layer structure with a paper straw layer on the inner layer and a wooden barrel layer on the outer layer, by heating the first molded article to harden and releasing the core pin from a second molded article, which is the heated first molded article.
2 more elements
Dependencies are inferred from the claim text.