JP2627077B2 - Core for writing instruments - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a writing instrument core having high strength against bending.

(Prior art and its problems) Conventionally, polypropylene has been used as a material for a pipe-shaped molded product used for a writing instrument core, for example, an oil-based ballpoint pen.

The core of this oil-based ballpoint pen is inserted into a hard armored shaft and is used.However, if it is stored as a cartridge without being inserted into the armored shaft, or if the armored shaft has a structure that can be bent for design or use, When an external force is applied to the core and the core is bent, using a conventional core, especially at low temperatures, when bent, buckling or cracking of the core-shaped pipe-shaped molded product occurs, There are problems such as ink leakage.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned problems. That is, the gist of the present invention is to provide a writing part and a writing instrument core made of a pipe-shaped molded article containing ink. The material for the pipe-shaped molded article is a mixture of soft polyethylene and hard polyethylene, and the soft core contains 10% by weight or more of soft polyethylene.

 Hereinafter, the present invention will be described in more detail.

As the pipe-shaped molded product, a mixture of soft polyethylene and hard polyethylene is used. Specific examples of the soft polyethylene include Suntech M2004 (manufactured by Asahi Kasei Kogyo Co., Ltd.) and Ultzex (Mitsui Petrochemical Industry Co., Ltd.)
), Patrocene (manufactured by Toyo Soda Co., Ltd.), Himilan (manufactured by Mitsui Polychemicals Co., Ltd.) and the like.
This is because the effect cannot be obtained.

Specific examples of hard polyethylene include Suntec B870 (manufactured by Asahi Kasei Corporation), Chisso Polyeth (manufactured by Chisso Corporation), and Novatec (Mitsubishi Kasei Kogyo Co., Ltd.)
And Nipolon Hard (manufactured by Toyo Soda Co., Ltd.). The amount of soft polyethylene is 90% by weight or less because the amount of soft polyethylene used is 10% by weight or more.
If the amount is more than the weight percentage, buckling or cracking occurs when bent at low temperature, and the effect cannot be obtained.

(Action) Polyethylene has a lower foaming temperature than polypropylene, so it is less likely to break when bent at low temperatures.

(Examples) Example 1 10 parts by weight of soft polyethylene 90 parts by weight of hard polyethylene The above components were mixed, and extruded to obtain a pipe-shaped molded product.

Example 2 50 parts by weight of soft polyethylene 50 parts by weight of hard polyethylene The above components were mixed and extruded to obtain a pipe-shaped molded product.

Example 3 25 parts by weight of soft polyethylene 75 parts by weight of hard polyethylene The above components were mixed and extruded to obtain a pipe-shaped molded product.

Comparative Example 1 A pipe-like molded product was obtained by extrusion molding using only polypropylene.

Comparative Example 2 Only a hard polyethylene was used and was extruded to obtain a pipe-shaped molded product.

Comparative Example 3 Only soft polyethylene was used and was extruded to obtain a pipe-shaped molded product.

(Effects) The results of bending resistance tests performed on the pipe-shaped molded articles obtained in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in the following table.

Thus, according to the present invention, a writing instrument core having high strength against bending can be obtained.

Claims (1)

(57) [Claims] 1. A writing instrument core comprising a writing section and a pipe-shaped molded article containing ink, wherein the material of the pipe-shaped molded article is a mixture of soft polyethylene and hard polyethylene, and the soft polyethylene is 10 A core for writing implements, characterized in that it contains not less than% by weight.