JPH03274200A - Pen tip of liquid writing instrument - Google Patents

Abstract

PURPOSE:To satisfy not only wear resistance, strength but also a writing taste by axially elongating a pipe molded from polyacetal resin, and engaging an ink guide core within the pipe. CONSTITUTION:Polyacetal resin is molded in a pipe state by using a thermoplastic resin molding machine. The pipe is elongated at 150 deg.C or lower, cut in a short length, its end is polished, and a movable guide core is engaged within the pipe. In order to obtain the pipe, it is desirable to use an extrusion molding machine in view of a manufacturing cost. The obtained pipe is cut in a short length, its end is polished in a conical state with roundness of 0.5mm in diameter to form a pen tip of highly elongating material.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has a structure in which a movable ink guide core is fitted inside a pipe, and has excellent abrasion resistance, strong strength, and writing quality. The present invention relates to a good liquid writing instrument nib and a method for manufacturing the same.

[Conventional technology]

Conventionally, metals or ceramics have been used as pipe materials for the nibs of this type of writing instruments. However, because the pipe material is metal or ceramic, even if the strength and abrasion resistance of the nib are satisfactory, it has the disadvantage of extremely poor writing quality, which is another important characteristic of the nib of a writing instrument. In particular, the thinner the line width is, the worse the writing quality tends to be, and the tip or paper fibers may be torn off from the paper, causing the paper fibers to dig into the ink drain pipe. It has drawbacks such as clogging and disturbing drawn lines.

Therefore, although it is widely used as a drafting tool, automatic drafting machine, and plotter, it is currently not used much as a writing instrument for handwriting.

[Problem to be solved by the invention]

An object of the present invention is to provide a pen nib of a liquid writing instrument that has satisfactory quality not only in abrasion resistance and strength but also in terms of writing taste and is suitable for use as a writing instrument for handwriting, and a method for manufacturing the same. do.

[Means to solve the problem]

As a result of intensive research to solve the above problems, the present inventors focused on the fact that polyacetal resin is a thermoplastic resin with high crystallinity, and by stretching it,
The present invention was completed by discovering that a pen nib with excellent writing taste while maintaining high abrasion resistance and strength can be obtained.

That is, the present invention is a pen nib for a liquid writing instrument, which is formed by stretching a pipe made of polyacetal resin in the axial direction and fitting an ink guide core inside the stretched pipe.

In addition, the manufacturing method involves forming polyacetal resin into a pipe shape using a molding machine for thermoplastic resins, stretching the pipe at a pipe temperature of 150°C or less, cutting the pipe into short lengths, and polishing the tip. , a method for manufacturing a pen nib for a liquid writing instrument, characterized by fitting a movable ink guide core inside a pipe.

Although polyacetal resin has high crystallinity, molded products of unstretched crystalline polymers usually contain a mixture of crystalline parts in which molecular chains are properly arranged and amorphous parts in which molecular chains are disordered. This amorphous portion causes a decrease in mechanical strength such as elastic modulus.

Therefore, in order to improve mechanical strength, it is necessary to adjust the molecular arrangement of this amorphous part and crystallize it.

Furthermore, the crystal part is a lamellar crystal with folded molecular chains, and in order to further improve the strength, it is necessary to unwind the folded molecular chains and align them in one direction.

In order to obtain the target pipe of the present invention, it is preferable to use a known extrusion molding machine or injection molding machine that is commonly used for molding thermoplastic resin, but from the viewpoint of manufacturing cost, it is preferable to use an extrusion molding machine. is preferred.

In any method, it is desirable that the speed of the melt flow and the melt temperature can be sufficiently controlled.

Next, the extruded pipe continuum is stretched.

The temperature of the pipe during stretching must be below 150°C.

This is because even if the polyacecool resin is stretched near its melting point in a nearly molten state, the apparent shape will change, but the strength will not be improved in any way.

The obtained pipe is cut into short lengths, and the tip is polished to a conical shape with a radius of about 0.5 mm to make a highly elongated pen nib. Note that there are no particular restrictions on the ink guide core fitted into the pipe.

[For production]

The highly stretched pen nib of the present invention has the following excellent effects.

(1) Both the amorphous portion and the crystalline portion have molecular chains oriented in one direction and have a dense crystal structure, so they have excellent abrasion resistance during writing.

(2) Since the elastic modulus and strength in the stretching direction are high, there is no drawback that the pen tip deforms or breaks during writing.

(3) Since the structural member of the pen nib is made of plastic, it has an excellent writing feel, unlike pen nibs made of glass, ceramics, various metals, etc.

(4) As the molding equipment, ordinary thermoplastic resin equipment can be used as is, mass production is possible, and the unit cost per piece is low.

〔Example〕

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

(Example) A polyacetal resin is extruded into a pipe shape using a hot melt extrusion molding machine. This molded product was stretched at a stretching ratio of 12 times, cut to a required length, and the tip was polished so as not to impair the writing quality to form a pipe. Next, a movable ink guiding core was fitted inside the pipe to complete the pen nib. I then assembled this nib into a writing instrument.

(Comparative Example 1) A liquid writing instrument consisting of a pen nib in which a movable ink guide core is fitted inside a commercially available metal pipe.

(Comparative Example 2) A military recorder consisting of a pen nib with a movable ink guiding core fitted inside a commercially available ceramic pipe.

The above sample was subjected to a writing taste test by an expert's sensory test. The results are shown in Table 1.

Unlike metal pen nibs, it not only provides an excellent writing feel, but also has excellent abrasion resistance, high elastic modulus, and high strength, so even when the line width is made thinner, the line width decreases as the writing length increases. It has a long life without becoming thick, and can be mass-produced using ordinary thermoplastic resin equipment as it is, so the actual cost can be reduced.

Table 1

Claims (2)

[Claims] (1) A pen nib for a liquid writing instrument, which is made by stretching a pipe made of polyacetal resin in the axial direction and fitting an ink guide core inside the stretched pipe. (2) Polyacetal resin is molded into a pipe shape using a molding machine for thermoplastic resin, and the pipe is molded at a temperature of 15°C.
A method for manufacturing a pen nib for a liquid writing instrument, which comprises stretching the pipe at 0° C. or lower, cutting the pipe into short lengths, polishing the tip, and fitting a movable ink guide core inside the pipe.