JPH062437B2 - Liquid writing instrument nib - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a liquid that has improved abrasion resistance, significantly extended writing life, and still retains a good writing quality as compared with a conventional nib. Regarding the pen tip of writing instruments.

(Prior Art) Conventionally, most of the nibs of this type are manufactured by press-molding a thermoplastic resin. As the resin, polyamide, polyurethane, polyacetal or the like is used alone or a filler is added to these resins. Compounded compounding agents are commonly used.

Although such a conventional nib has a drawback that the liquid such as ink plays a role of a lubricant due to sliding friction during writing, it has a drawback that the wear is relatively large. This tendency was remarkable when used or for paper having a large surface roughness. That is, all of the resins used for conventional pen nibs have insufficient abrasion resistance that affects the writing life. When the pen tip has low abrasion resistance, the following problems occur in the design of the liquid writing instrument. In other words, the amount of ink stored in the ink storage material and the writing life of the pen tip cannot be balanced, and the writing life of the pen tip is extended even though there is sufficient ink remaining in the ink storage material. The liquid writing instrument becomes unusable.

Therefore, by converting the ink occlusion body into a cartridge,
The intention to extend the life of a writing instrument significantly is also impossible. To improve the wear resistance of the nib, for example, it is possible to manufacture the nib by using glass, ceramics, various metals, etc., but the writing feel is much better than that of the plastic nib. It has the bad effect of being poor. In particular, the thinner the line width of the writing, the worse the writing quality tends to be. Moreover, there are drawbacks such as the fact that fibers of the paper bite into the ink outflow gap to cause clogging and disturb the drawn line.

Further, since the conventional resin nib has a small bending elastic modulus and bending strength of the material, there is a drawback that the tip of the nib is deformed or dislocated during writing.

(Problems to be Solved by the Invention) The present invention solves the problems of the above-described conventional pen tip,
By improving abrasion resistance, the writing life is greatly extended, the writing feel is good, and it has a high elastic modulus and bending strength, and it can be manufactured at low cost using an industrially simple method. The purpose is to provide a nib for the obtained liquid writing instrument.

(Means for Solving the Problems) The pen tip of the liquid writing instrument of the present invention devised to achieve the above-mentioned object is characterized by being formed using a compounded composition containing a thermoplastic liquid crystal polymer as a material. It is what

The thermoplastic liquid crystal polymer used in the present invention is an aromatic polyester resin, and is generally terephthalic acid, 6-hydroxy-2naphthalenecarboxylic acid, piphenol, for parahydroxybenzoic acid or paraacetoxybenzoic acid. It is a copolymer of one or more polyethylene terephthalates. In the present invention, a known or commercially available liquid crystal polymer having thermoplasticity can be used.

Further, the compounded composition of the present invention must be the above liquid crystal polymer as a whole or at least contain the liquid crystal polymer. Preferably, the content of the liquid crystal polymer in the blended composition is 20 wt% or more, which gives good results in utilizing the rigidity and orientation of the liquid crystal polymer. As another compounded composition, a thermoplastic resin capable of polymer blending with a liquid crystal polymer, an inorganic or organic filler, or both of them may be added. As the thermoplastic resin capable of polymer blending, known thermoplastic resins such as polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyamide, and polycarbonate can be used.Also, as an inorganic or organic filler, calcium carbonate, talc, clay,
Fillers such as graphite, short glass fibers, short carbon fibers, wood powder, and short aramid fibers can be used. In addition, various additives such as stabilizers may be added if necessary.

In the present invention, a known extruding machine or an injection molding machine used for molding a thermoplastic resin can be used to manufacture a pen point from the above-mentioned blended composition, but in order to secure a gap for ink outflow in the molded product. From the viewpoint of manufacturing cost, it is preferable to use an extruder. In any method, it is desirable to be able to sufficiently control the melt flow rate and the melt temperature.

(Function) In a normal thermoplastic resin, molecules are entangled in a molten state, and the degree of orientation is small even if shear stress is applied at the time of molding, but the liquid crystal polymer is made of rigid molecules, and in the molten state, the molecules are Since it does not bend in an orderly manner and maintains a rod shape, it has the property of being largely oriented in one direction even if it receives a slight shear stress. As a result, the structure of the molded product has a dense crystal structure in which rigid molecules are oriented in the flow direction, and the abrasion resistance of the pen tip is extremely improved.
Further, in the liquid crystal polymer, the molecular chains are oriented in the flow direction during molding and self-reinforce, so that the elastic modulus and bending strength of the pen tip are increased.

Further, since the liquid crystal polymer is of course plastic, unlike the nibs of glass, ceramics, various metals, etc., the writing quality does not deteriorate.

(Example) Example 1 Liquid crystal polymer 80 wt%, polyethylene terephthalate 20 wt
% Of the compounded composition is molded by using an extrusion molding machine equipped with a die having a large number of small holes arranged so as to be fused so as to have a gap with a modified cross section after heat melt extrusion molding, Short cutting was performed to obtain a nib having a gap of irregular cross section.

Example 2 A compounding composition comprising a liquid crystal polymer containing 25 wt% of graphite powder was fused at the tip of a die having a large number of small holes so as to be fused after heating and melt extrusion so as to have gaps of irregular cross section. Molding was carried out using the equipped extruder, and short cutting was performed to obtain a pen tip having a gap of irregular cross section.

(Test Results) Assemble the pen tip obtained in the above example into a writing instrument,
The results of the measurement of the amount of wear of the pen tip by a mechanical writing tester, the three-point bending test of bending elastic modulus and bending strength, and the writing quality evaluation test by a sensory test by an expert are shown in the following table. As a comparative example, a test result of a pen tip manufactured by using the polyacetal resin in the same process as the example is also shown.

(Effects of the Invention) As is apparent from the above test results, the pen tip formed by using the compounded composition containing the thermoplastic liquid crystal polymer according to the present invention has a significantly improved abrasion resistance as a result of the above test results. The life of the tip was extended, and although the ink could still be written with a short writing distance with the conventional nib, it is now possible to write even with a significantly longer writing distance. Therefore, it is particularly effective when writing by a person with a high writing pressure or when writing on paper with a high surface roughness, and it is also used as a pen tip for various recorders that must be written over a long period of time. Can be extremely useful,
Further, there are various advantages such as the fact that an ink cartridge type marking pen can be put to practical use.

Next, since the elasticity and bending strength of the pen tip increase, the drawback that the tip of the pen tip is deformed or broken during writing is eliminated. Further, the writing quality is also good as in the above evaluation test. Further, as the molding equipment, the usual equipment of thermoplastic resin can be used as it is, so that a large amount of processing is possible and the cost per one can be kept small.

Therefore, the above object is completely achieved.

Claims (1)

[Claims] 1. A pen tip of a liquid writing instrument having an ink outflow gap, which is formed by using a compounded composition containing a thermoplastic liquid crystal polymer as a material.