JPH0761756B2 - Fiber nibs - Google Patents

Description

The present invention relates to a nib made of a hard fiber bundle for a liquid writing instrument.

(Prior Art) A conventional nib made of a hard fiber bundle is made by extruding a thermoplastic resin such as polyamide, polyolefin, aliphatic polyester, acrylonitrile, etc. to bundle organic fibers, which are then bonded with a binder resin. It is manufactured by hardening.

(Problems to be Solved by the Invention) In the above-mentioned conventional nib made of a hard fiber bundle, although the liquid such as ink plays a role of a lubricant, it is relatively worn due to friction during writing. have. In particular, when a person with a high writing pressure writes, or when writing on a paper having a large surface roughness, the abrasion is remarkable. When the wear resistance of the pen tip is small in this way, not only is it possible to use fine writing at first, but the drawing line will become thick in a short time due to use, and it will also affect the life of the writing tool, and it will affect the life of the writing instrument. The design has the following disadvantages. That is, since the life of the liquid writing instrument is restricted by the life of the pen tip, increasing the ink storage amount of the ink storage material does not lead to the extension of the life of the liquid writing material, and therefore the ink storage element is replaced by the cartridge. The method has little utility.

The above-mentioned conventional pen nib also has the drawback that the tip of the pen nib is deformed or broken (cracked) during writing because the bending elastic modulus and bending strength of the material are small.

By the way, if only a pen tip having excellent wear resistance and a large bending elastic modulus and bending strength is obtained, the problem can be solved by concentrating and using filaments made of glass, ceramics, or various metals. However, fiber nibs obtained from these materials are inferior in toughness and impact resistance as compared to plastic fiber nibs, and have extremely poor writing quality, which is an important characteristic as a writing instrument (especially The thinner the stroke, the worse the writing feel.) In addition, the tip of the pen tip fiber tears away the paper fiber to let it penetrate into the ink outflow gap. There was a problem such as clogging and easy disturbance of drawing lines.

Therefore, the present invention has excellent wear resistance and a long writing life,
Further, a fiber nib having a bending strength and a bending elastic modulus that prevent the nib from being deformed or dislodged, and that the writing feel is excellent, and that the nib can be manufactured at low cost by industrially simple means is obtained. That is the purpose.

(Means for Solving the Problems) The fiber nib of the present invention has been devised to achieve the above-mentioned object, and is formed by molding a thermoplastic liquid crystal polymer or a compounded composition containing the liquid crystal polymer. The filaments obtained as described above are bundled, and the filaments are bonded and cured with a binder resin.

In the present invention, first, a thermoplastic liquid crystal polymer or a compounded composition containing the liquid crystal polymer is molded using a known extruder to form filaments of long fibers. The thermoplastic liquid crystal polymer used here is used. The term “aromatic polyester-based resin” generally refers to parahydroxybenzoic acid, paraacetoxybenzoic acid, etc., in addition to terephthalic acid, 6-hydroxy-2naphthalenecarboxylic acid, biphenol, polyethylene terephthalate, etc. It is obtained by copolymerizing at least one species. It is possible to use a known or commercially available thermoplastic liquid crystal polymer in the present invention.

The molding material of the filament of the present invention must be a liquid crystal polymer as a whole, or a compounded composition containing at least a liquid crystal polymer, and the content of the liquid crystal polymer in the compounded composition is 20 wt% or more. Is desirable. This is because in this range, the rigidity and orientation of the liquid crystal polymer are exhibited extremely well, and good results are obtained.

The other component in the blended composition is a thermoplastic resin capable of polymer blending with the liquid crystal polymer. For example, thermoplastic resins such as polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyamide and polycarbonate can be used. Further, various additives such as stabilizers can be added as necessary.

In the present invention, next, the filaments described above are bundled, subjected to adhesion / curing treatment by a known method using a binder resin, then cut into short pieces, and further subjected to processing treatment such as polishing on the tip. A hard fiber nib is obtained with a binder resin, and the binder resin used here may be a natural resin or a synthetic resin, but preferably a phenol resin or a urea resin in consideration of the quality and productivity of the resulting nib. It is preferable to use one or more thermosetting resins such as melamine resin, furan resin, unsaturated polyester resin, epoxy resin and polyurethane resin. The amount of binder resin is
Depending on the porosity and mechanical strength required by the pen tip, 5 to 50 parts by weight is suitable for 100 parts by weight of filament.

(Operation) The liquid crystal polymer consists of rigid molecules throughout its structure. In the molten state, the molecules do not tend to bend in an orderly manner and maintain a rod shape, so they have the property of being largely oriented in one direction by a slight shear stress. is doing. As a result, the nib formed by using the liquid crystal polymer or the compounded composition containing the liquid crystal polymer as a material has a dense crystal structure, and the abrasion resistance against friction during writing is improved. Next, the liquid crystal polymer or a compounded composition containing the liquid crystal polymer has its molecular chains oriented in the flow direction during molding and self-reinforces, so that the bending elastic modulus and bending strength in this direction become large, and accordingly The tip of the pen tip thus formed is unlikely to be deformed and is unlikely to come apart. Next, since the filament constituting the nib is made of a liquid crystal polymer or a compounded composition containing a liquid crystal polymer, the nib is a plastic nib, and a pen such as glass, ceramics, or various metals is used. The writing is much better than before, and also
Since the liquid crystal polymer has excellent vibration absorption characteristics, the smoothness of writing feel is further improved. Next, for molding filaments with a thermoplastic liquid crystal polymer or a compounded composition containing the liquid crystal polymer, a usual thermoplastic resin extrusion molding machine can be used as it is and mass molding is possible. The cost is low, and because the liquid crystal polymer has a higher softening point than ordinary thermoplastic resins, the curing treatment temperature of the binder resin can be set to a high temperature, so the treatment time can be shortened by using a thermosetting resin as the binder resin. It is also possible, and the cost merit is great.

(Example) A liquid crystal polymer was melted by heating and then extrusion-molded to obtain a filament of 3 denier, which was then bundled and immersed in an alcohol solution containing 20 wt% of a phenol resin as a binder resin, and then the filament. Appropriately squeeze out excess binder resin liquid so that the content of the dried and cured phenol resin is 25 parts by weight with respect to 100 parts by weight, and then pass through a heating oven set at 160 ° C for curing treatment. Then, it was cut into short pieces, and further polished so that the tip end portion was conical and the protruding end portion of the conical portion was 0.5 mmR to obtain a hard fiber pen core having a diameter of 1.5 mm.

Further, the polyamide resin was melted by heating and then extrusion-molded to obtain a filament of 3 denier, and thereafter the curing temperature of the phenol resin was set to 130 ° C., under the same conditions as in the above-mentioned example and in the same step as in the above-mentioned example. Thus, a hard fiber bundle nib of a comparative example was obtained.

Twenty pen tips of each of the above-mentioned Examples and Comparative Examples were assembled into a writing tool, and the amount of wear was measured after 800 m writing with a mechanical writing tester. The results are shown in Table 1 below.

The pen nibs of the above Examples and Comparative Examples were assembled into a writing instrument, and the width of the drawn line after 200 m writing was measured by a mechanical writing tester. The results are shown in Table 2 below.

The three-point bending test of the nibs of the above Examples and Comparative Examples was performed to measure the bending strength and bending elastic modulus. The results are shown in Table 3 below.

Assemble the writing nibs of the above-mentioned examples and comparative examples into a writing instrument.
A writing test was conducted by a sensory test of a person skilled in the art. The results are shown in Table 4 below.

The conditions of the writing test by the above mechanical writing tester were in accordance with (JIS-S-6037-1986 marking pen) except that the writing load was 100 gf.

(Effect of the invention) Since the fiber nib of the present invention is configured as described above, wear resistance is improved, change in the line width of the writing line is suppressed, and bending strength and bending elastic modulus are increased. It is also clear from the above test results that a very good writing quality can be obtained. This improvement in abrasion resistance extends the life of the pen nib itself, and correspondingly increases the ink storage capacity of the ink occlusion body, or replaces the ink occlusion body with a cartridge type that allows replacement of the writing tool life. It is possible to postpone. This nib with improved abrasion resistance is extremely useful as a writing instrument used by a person with high writing pressure and for various recorders that require long-term writing. Next, since the change in the line width of the drawn line is small, a uniform and beautiful drawn line can be obtained.
In addition, since the bending strength and the bending elastic modulus are increased, the pen tip is prevented from being deformed or scattered, so that a good writing feeling and a beautiful drawn line can be obtained. Further, the filament constituting the fiber nib of the present invention has an advantage that it can be manufactured at a low cost because it can be mass-molded by using an extruder used for molding a usual thermoplastic resin.

Claims (1)

[Claims] 1. A fiber nib formed by bundling filaments obtained by molding a thermoplastic liquid crystal polymer or a compounded composition containing the liquid crystal polymer, and adhering and curing the filaments with a binder resin.