JPH03246098A - Pen point of liquid writing utensil - Google Patents

Abstract

PURPOSE:To enhance abrasion resistance and to improve a writing feeling by stretching a molded body of a polyacetal resin in such a state that gaps having a profile cross-section for the outflow of ink are opened to the outside in the axial direction thereof to prepare a pen point. CONSTITUTION:A polyacetal resin is melted under heating and formed into a continuous body in such a state that gaps having a profile cross-section for the outflow of ink are opened to the outside by extrusion molding using an extrusion molding machine having a die to which a large number of small holes are arranged provided to the leading end thereof. This molded body is stretched by a microwave heating and stretching apparatus, for example, set to 12 times in its stretch ratio and shortly cut to obtain a pen point having gaps of a profile cross-section. This pen point is used, for example, by radially opening gaps 1 to the outer surface thereof in the radius direction thereof and mounting a pipe 3 on the outer peripheral part thereof if necessary. The polyacetal resin is a material having a simple molecular structure and capable of easily generating the rearrangement of a molecular chain by weak bipolar mutual action and, since the stretched pen point has a dense unidirectionally oriented crystal structure, the abrasion resistance thereof at the time of writing can be enhanced and an excellent writing feeling can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pen nib for a liquid writing instrument in which a gap of irregular cross section for ink flow is provided in the axial direction. The present invention relates to a pen nib for a liquid writing instrument which increases the amount of water and provides good writing taste.

[Conventional technology]

Most of the pen nibs of conventional liquid writing instruments, which have a gap in the axial direction with a irregular cross section for ink to flow out, are made by extrusion molding of thermoplastic resins that are melted by heat. Generally, single materials such as polyamide, polyurethane, polyacetal, etc., or composite materials in which fillers are blended with these resins have been used.

Although pen nibs molded using conventional thermoplastic resin play the role of liquid such as ink or lubricant during sliding friction during writing, they have relatively large drawbacks such as wear and tear. This tendency was particularly noticeable when the paper was used by a person with high writing pressure or on paper with a large surface roughness. In other words, all of the above-mentioned resins have some problems with respect to abrasion resistance, which affects the writing life of the pen tip. Therefore, this low abrasion resistance is a major obstacle in the design of liquid writing instruments, and the following two points can be mentioned in particular.

The point is that there needs to be a balance between the amount of ink stored in the ink absorber and the amount of wear on the pen tip, but since conventional pen tips have a large amount of wear, there is enough ink remaining. Despite this, the lifespan of liquid writing instruments is limited by the wear of the pen tip.

Another point is whether it is possible to significantly extend the writing life by converting the ink storage body into a cartridge/nozzle, and the reason is that the wear resistance of the conventional pen nib with an irregular cross section and a gap for ink flow is low. Therefore, it is hardly useful to use a liquid writing instrument with a replaceable ink cartridge.

[Problem to be solved by the invention]

By the way, the present inventor has been researching pen nibs with various gaps for ink to flow out, and has found materials with high wear resistance,
Although abrasion can be solved by using glass, ceramics, various metals, etc., compared to pen nibs made of plastic materials, these materials have poor writing quality, which is another important characteristic of a writing instrument nib. It has the disadvantage of being very poor, and in particular, the thinner the line width is, the worse the writing quality tends to be, and the paper fibers etc. can get stuck in the gaps for ink to flow out, causing eye irritation. This had problems such as clogging and disturbing the drawn lines.

Therefore, the present invention has been made in consideration of the above circumstances.
The aim is to significantly improve writing life and abrasion resistance, which were previously unobtainable.
Moreover, it is an object of the present invention to provide a pen nib of a liquid writing instrument which has a much better writing taste and is manufactured at a low cost using an industrially simple method.

[Means to solve the problem]

As a result of intensive research to achieve the above object, the present inventor has
The molded product obtained by molding polyacetal resin is stretched at a high magnification in the axial direction, and the filament with this high stretching magnification becomes the nib of a liquid writing instrument that has excellent writing properties, especially abrasion resistance and writing taste. The present invention was completed.

That is, a molded product of an unstretched crystalline polymer usually has 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, this amorphous part must be crystallized by adjusting the molecular arrangement, and the crystalline part is a lamellar crystal with folded molecular chains. It is necessary to unravel the molecular chains and orient them in one direction.

Polyacecool resin is a material that can easily rearrange its molecular chains due to its simple molecular structure and weak dipole interaction, and is a material that can be used as a pen tip for reasons such as formability, abrasion resistance, and ink wettability. preferable.

In order to obtain the desired pen nib of the present invention, it is preferable to use a known extrusion molding machine or injection molding machine that is used for molding ordinary thermoplastic resins. It is preferable to use an extrusion molding machine from the viewpoint of manufacturing cost. In any method, it is desirable that the speed of the melt flow and the melt temperature be sufficiently controlled.

Next, the molded product of crystalline polymer having a structure provided in the axial direction is stretched with the gap of the irregular cross section for ink flow opened to the outside obtained by extrusion molding. The temperature of the molded product during this stretching must be 150°C or lower. This is because there is no improvement in strength even if the polyacetal resin is stretched near its melting point. Then, a pen nib can be created by cutting the obtained stretched product into short lengths and polishing the tip into a pen nib shape. Further, if necessary, a pipe may be attached to the outer periphery or the outer periphery may be covered with plastic.

[For production]

The stretched pen nib obtained by the present invention has the following excellent advantages.

(1) Since both the amorphous portion and the crystalline portion are oriented in one direction and have a dense crystal structure, it has excellent abrasion resistance during writing.

(2) The strength of the pen core itself has been increased, so even people who use high writing pressure will not damage the pen tip.

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

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

(5) Since the irregular cross-section for ink flow is open to the outside, the tip can be made sharp, and therefore various line widths can be created by changing the shape of the polishing.

In addition, the product can be stretched to a similar shape during stretching, and a stable product can be obtained even when extrusion molded using a liquid crystal polymer.

〔Example〕

Next, the present invention will be explained in more detail based on examples.

The polyacetal resin is heated and melted, and a continuous body is extruded using an extrusion molding machine with a gap of irregular cross section for ink outflow open to the outside. This molded product was stretched using a microwave heating stretching device at a stretching ratio of 12 times, and cut into short lengths to obtain a pen nib with a gap in the irregular cross section. This pen nib was assembled into a writing instrument, and the abrasion resistance was measured by measuring the amount of wear on the nib when writing with a mechanical writing tester, and the writing feel was evaluated by a sensory test conducted by an experienced evaluator. Further, the bending elastic modulus was determined to be 71P1 with the pen tip intact. The results are shown in Table 1.

Polyacetal resin is a material in which rearrangement of molecular chains can easily occur due to its simple molecular structure and weak dipolar interaction, and is preferable for reasons such as moldability as a pen nib, abrasion resistance, and ink wettability.

The above-mentioned microwave heating stretching apparatus will be explained based on FIG. 1. In the same figure, a stretching device for stretching a hollow continuous body having an ink flow gap obtained by extrusion molding with an extrusion molding machine 10 and red coloring in a cooling tank 11 is used for heating the molded body by microwave heating. It is composed of a device 20, a feeder 12 which serves to stretch the heated material, and a take-up device 13. The microwave heating device 20 includes an oscillator 21, a cylindrical waveguide 22 for heating, and a rectangular waveguide 23 connecting these.
, a dummy 24 that absorbs excess microwaves.

Further, an embodiment of a gap of irregular cross section for ink to flow out at the pen tip will be described with reference to FIGS. 2 to 8. The first embodiment shown in Fig. 2 has a pen nib 2 in which a radial gap 1 is opened radially on the outer surface, and if necessary, a pipe 3 is attached to the outer periphery as shown in Fig. 3 for use. do. Further, in the second embodiment shown in FIG. 4, a branch-like gap 1 in the circumferential direction is connected to a pen nib 2 in the middle of a radial gap 1 opened on the outer surface in the radial direction.
It is.

Furthermore, the third embodiment shown in FIG. 5 has a semicircular pen nib 2 with several parallel gaps 1 opened on the flat surface, and a pair of symmetrical pen nibs 2 as shown in FIG. They are combined and fixed by attaching a pipe 3 to the outer periphery.

The fourth embodiment shown in FIG. 7 has a fan-shaped gap 1 with a complicated shape that opens toward the center, and as shown in FIG. and fix it.

[Comparative example]

Polyacetal resin is heated and melted, and after extrusion molding, it is molded using an extrusion molding machine equipped with a die at the tip with many small holes arranged so that there are gaps in the irregular cross section, and then cut into short lengths to create gaps in the irregular cross section. A pen nib having the following properties was obtained.

Measurement of the bending elastic modulus of the pen tip obtained by the above operation,
After assembling it into a writing instrument, the amount of wear was measured using a writing tester, and the writing feel was tested using a sensory test by an expert. The results are also shown in Table 1.

〔Test results〕

Table 1 However, in the abrasion loss test, the conditions for the writing test using a mechanical writing tester were that only the writing load was 100g, but the other conditions were t2 in accordance with JIS-5-6037-1986 hooking pen.

〔Effect of the invention〕

As explained above, the pen tip according to the present invention has writing characteristics,
In particular, it has excellent abrasion resistance and writing quality, and as is clear from the test results above, with conventional pen nibs, even though there is sufficient ink remaining, it becomes impossible to write after a short writing distance. However, it became possible to write over a significantly longer distance, and as a result, it became extremely useful as a writing instrument with high writing pressure and as a pen tip for various recorders, and it was also possible to use cartridges as an ink storage body. It becomes possible to realize this and significantly extend the writing life.

In addition, of course, carbon copying and non-carbon copying are also possible.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a microwave heating and stretching apparatus used in carrying out the present invention, Fig. 2 is a cross-sectional view showing the first embodiment of the present invention, and Fig. 3 is another use of the first embodiment. FIG. 4 is a cross-sectional view showing the second embodiment of the present invention, FIG. 5 is a cross-sectional view showing the third embodiment of the present invention, and FIG. 6 is a cross-sectional view of the third embodiment. FIG. 7 is a cross-sectional view showing a fourth embodiment of the present invention, and FIG. 8 is a cross-sectional view showing another mode of use of the fourth embodiment. DESCRIPTION OF SYMBOLS 1... Gap, 2... Pen tip, 3... Nonobu, 10... Extrusion molding machine, 20... Microwave heating device.

Claims (1)

[Claims] A molded product of polyacetal resin is formed in the axial direction with a gap of irregular cross section for ink flow open to the outside.
A pen nib for a liquid writing instrument characterized by being manufactured by stretching in the axial direction.