JPH04355196A - Pen point lead for writing utensils and production thereof - Google Patents

Abstract

PURPOSE:To obtain a pen point lead for writing utensils containing no obstacle filling voids between fibers and imparting uniform ink flowability which prevents ink from becoming blurred at the time of writing. CONSTITUTION:A pen point lead for writing utensils is made of a fiber aggregate thermally fused to be 0.15-0.75 in density. The fiber aggregate contains 50wt.% or more acrylic fiber.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pen nib used in writing implements such as felt-tip pens and markers, and a method for manufacturing the same.

0002

2. Description of the Related Art Conventionally, wool felt has been used for the nib of writing instruments such as felt-tip pens and markers. In addition, recently, molded products are known in which synthetic fiber bundles such as vinylon, nylon, acrylic, and polyester are impregnated with thermosetting resins such as melamine, epoxy, and phenol, or thermoplastic resins such as polyurethane, and then compressed and heated. . For example, Japanese Patent Publication No. 42-7165 discloses a molded article using melamine resin. Furthermore, there are also known molded products that are integrated by heating and melting a part of the product without using an impregnating liquid. For example, Japanese Patent Publication No. 53-47730 discloses a molded article in which core-sheath composite fibers made of polyethylene and polypropylene having different melting temperatures are thermally fused at a temperature above the melting point of polyethylene and below the melting point of polypropylene.

0003

[Problem to be Solved by the Invention] However, the above-mentioned wool felts are only given strength and hardness by the intertwining of the wool scales, so the fibers loosen and lose their shape. It has the disadvantage of being easy. In addition, when the above-mentioned wool felt is cut into thin pieces, the fiber length becomes short and the strength further decreases, so that a thin core cannot be formed and a product for fine print cannot be obtained.

On the other hand, there are two types of molded products made by impregnating synthetic fiber bundles with resin: those impregnated with a resin solution and those impregnated with a resin emulsion liquid, but each has the following problems. , improvement is required. In the former case, since the solvent is often a harmful organic solvent, it is necessary to install equipment to dry and recover this solvent from the impregnated product, which requires a large investment in equipment and increases costs. There is a problem. In addition, in the latter case, the emulsion is scattered in the fiber bundle, and the voids between the fibers are filled with resin in places, which prevents the smooth flow of ink during use and tends to cause ink smearing. be. And these things are
There is also the problem that the ink may change in quality and coagulate due to the resin remaining in the fibers.

Furthermore, molded products made by heat-sealing the above-mentioned core-sheath type composite fibers are, for example, polyethylene/polypropylene core-sheath type composite fibers, which are heat-sealed using the difference in melting point between polyethylene and polypropylene. Since the polyethylene becomes liquid and collects in lumps at the melting point due to surface tension, the lumps of polyethylene close the gaps between the fibers, resulting in the same problems as those using the resin emulsion described above.

The present invention has been made in view of the above circumstances, and provides a writing instrument that does not contain foreign matter that would block the interfiber spaces, has uniform ink fluidity, and does not cause the ink to become blurred when writing. The purpose of the present invention is to provide a pen nib for use with pens and a method for manufacturing the same at low cost.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a pen nib core for a writing instrument made of a fiber aggregate heat-sealed to a density of 0.15 to 0.75, which The first aspect is a writing instrument nib core in which 50% by weight or more of the fiber aggregate is composed of acrylic fibers, and 0.5% by weight or more of a solvent for acrylic fibers is attached to the acrylic fibers. process, and the above solvent coated acrylic fiber is 50%
A method for manufacturing a pen nib for a writing instrument, comprising the steps of creating a fiber bundle uniformly mixed at a weight percent or more, and passing the fiber bundle through a guide maintained at 200° C. or higher and simultaneously fusing it under pressure and heat. The second gist is a step of adhering 0.5% by weight or more of a solvent for acrylic fibers to acrylic fibers, and a step of creating a sliver in which 50% by weight or more of the solvent-coated acrylic fibers are uniformly mixed. , a step of forming the sliver into a rod shape by heat-sealing the solvent-coated acrylic fibers to each other by passing the sliver under pressure through a nozzle whose surface temperature is set to 200° C. or higher; and forming the rod-like body into a predetermined length. The third gist is a method for manufacturing a pen nib for a writing instrument, which includes the steps of cutting into pieces and forming the nib into a pen nib shape.

[0008]

[Operation] That is, in the present invention, by attaching a solvent to acrylic fiber and swelling the fiber surface, only the fiber surface can be heat-sealed, and the inside of the fiber may be melted depending on the heat-sealing temperature. I tried not to do that. Therefore, the fiber aggregate obtained by heat-sealing these solvent-coated acrylic fibers is bonded where the fibers touch each other, ensuring a certain level of strength and also sealing the voids between the fibers. There is no chance that I will be disappointed. Therefore, ink smearing does not occur during use, unlike in the case of conventional inks impregnated with resin emulsion or core-sheath type composite resins. In addition, since sufficient strength is ensured, it can be formed into thin shapes for fine characters.

Next, the present invention will be explained in detail.

Acrylic fibers used in the present invention include:
In addition to acrylic fibers made of polyacrylonitrile made by homopolymerizing only acrylonitrile, acrylic fibers made of copolymers made of acrylonitrile as a main component and blended with various copolymer monomers can be mentioned. As the copolymerizable monomer, methyl acrylate, vinyl acetate, acrylamide, acrylic acid, vinyl chloride, vinylidene chloride, etc. are used alone or in combination of two or more. However, the amount of these copolymerizable monomers used is preferably set to 60% by weight (hereinafter abbreviated as "%") or less based on the total weight. In addition, other copolymerizable monomers include sodium allylsulfonate, sodium methacrylsulfonate, 2-acrylamide 2
- Sodium methylpropanesulfonate and the like can be used alone or in combination of two or more. The amount of these copolymerized monomers used is 0.5 to 4
It is preferable to set it to %.

The acrylic fiber of the present invention can be obtained from the above monomer by any known method. Examples of such acrylic fibers include commercially available products such as Cashmiron (manufactured by Asahi Kasei Co., Ltd.), Exlan (manufactured by Japan Exlan Co., Ltd.), Bonnel (Mitsubishi Rayon), and Veslon (manufactured by Nihon Exlan Co., Ltd.).
(manufactured by Toho Rayon Co., Ltd.), Toleron (manufactured by Toray Industries, Inc.), and Kanekalon (manufactured by Kanekabuchi Chemical Co., Ltd.).

The acrylic fiber of the present invention may be dyed or spun-dyed cotton.

[0013] Furthermore, as the solvent used in the present invention, an acrylic solvent generally used in the production of acrylic fibers can be used. For example, dimethyl sulfoxide (DMSO), dimethylacetamide (DMA), dimethylformamide (DMF), sulforane (SO)
, Elalene carbonate (EC), etc. Among them, SO having a high boiling point is preferred. However, these may be used alone or in combination of two or more.

[0014] In the present invention, the above-mentioned solvent is uniformly adhered to the above-mentioned acrylic fiber. At this time, it is necessary to set the adhesion amount to 0.5% or more based on the fiber weight, and preferably 1% or more. This is because if the amount of adhesion is less than 0.5%, the resulting solvent-coated acrylic fibers will not have sufficient heat fusion and will be difficult to form into a pen tip core. Another way to apply the solvent is to spray the solvent directly onto the fiber surface and then mix the fibers thoroughly, but with this method it is difficult to spread a small amount of solvent evenly over the entire fiber. Therefore, it is preferable to dilute the above-mentioned solvent with an easily volatile diluent such as water or acetone, and spray this diluted solution uniformly onto the acrylic fibers, or immerse the acrylic fibers in this diluted solution. A solvent-coated acrylic product in which the fiber surface is swollen by the solvent, and the diluent is removed by volatilization by attaching the solvent to the fiber surface by either the spray method or the dipping method described above, and then drying under specified conditions. Fiber can be obtained.

[0015] The drying temperature of the solvent-coated acrylic fiber is preferably set to 70°C or lower, particularly 60°C or lower. That is, as drying progresses, the solvent on the fiber surface impregnates the inside of the fiber surface, promoting swelling of the fiber surface, but if the drying temperature is too high, the fibers will adhere to each other. In particular, if the temperature exceeds 80°C, adhesion will become significant, which is not preferable. However, if the fibers are somewhat stuck together due to drying, the fibers may be opened thoroughly before blending.

The solvent-coated acrylic fiber thus obtained can be formed into a nib core for a writing instrument, for example, in the following manner. That is, first, the solvent-coated acrylic fibers are formed into a web according to a conventional method. At this time, only the solvent-coated acrylic fibers may be used, or other fibers may be mixed. However, it is necessary to set the amount of solvent-coated acrylic fibers to 50% or more, and if you want to obtain a stronger product, you can increase the blending ratio of solvent-coated acrylic fibers. On the other hand, if the solvent-coated acrylic fiber is less than 50%, the resulting molded product will not have sufficient strength and will not be of good quality as a product.

[0017] The obtained web is subjected to a heat treatment by applying it to a conventional thermal calender and is thermally fused to form a non-woven fabric. The adhesive strength of this nonwoven fabric is determined by the surface temperature of the thermal calendar,
Although it varies depending on the applied pressure, web thickness, fabric weight, web passing time, etc., for example, when a web with a fabric weight of 150 g/m2 is heat-treated with a thermal calendar surface temperature of 200°C and a roller weight of 10 kg gauge, the above-mentioned solvent-coated acrylic fibers It is necessary to set the mixing ratio to 50% or more. Furthermore, in order to obtain a nonwoven fabric with strong adhesive strength, the mixing ratio of solvent-coated acrylic fibers may be increased. In addition, the mixing ratio is 75%
If it is less than 100%, it is preferable to lengthen the passage time of the web and increase the applied pressure of the thermal calendar. Also,
When a pen nib with high hardness is required, it is preferable to set the thermal calendar surface temperature to 230° C. or higher. The nonwoven fabric thus obtained can be punched out using a press in accordance with a mold to produce a nib core for a writing instrument.

Furthermore, instead of forming the nib core through a nonwoven fabric as described above, the nib core can also be formed from a sliver. In this case, a sliver is made using only solvent-coated acrylic fibers or a uniform mixture of solvent-coated acrylic fibers and other fibers according to a conventional method. Then, by passing this sliver through a heated cap under pressure, a pen tip core can be obtained. In addition, the surface temperature of the above-mentioned cap should be 200°C or higher, especially 230°C if you want to obtain a pen tip with high hardness.
It is preferable to set the temperature to ℃ or higher.

[0019] For both the method using the nonwoven fabric and the method using the sliver, it is necessary to set the density of the pen tip core to 0.15 to 0.75.
Among these, it is preferable to set it to 0.2 to 0.7. That is, if the density is less than 0.15, the strength and hardness of the nib core will be insufficient, and the ink holding power will be insufficient, causing ink to fade when the nib is turned upward. Conversely, if the density is 0.
When it exceeds 75, the inter-fiber voids in the pen tip core decrease,
This impedes the fluidity of the ink and causes ink to fade.

[0020] The pen nib for writing instruments thus obtained has no impurities between the fibers and the ink has good fluidity, so the ink does not smudge when writing. Also,
Appropriate strength and hardness can be maintained depending on the application and shape.

Next, examples will be shown together with comparative examples.

[0022]

[Examples 1 to 3, Comparative Example 1] Commercially available Kanebo Acrylic R
K1BR3dx102mm (manufactured by Kanebo Co., Ltd.) was used as the raw material acrylic fiber. 10g of this acrylic fiber
The sample was immersed in 00 ml of an aqueous solvent solution under the conditions shown in Table 1 below. The heat fusion strength of this treated product was evaluated and is also shown in Table 1 below.

[0023]

[Table 1]

[0024]

[Examples 4 to 7] Solvent deposition was carried out under the same conditions as in Example 1 above (3.8% SO attached), squeezed with a centrifugal dehydrator, and then dried with a hot air dryer under the conditions shown in Table 2 below. did. The solvent-coated acrylic fibers thus obtained were opened, and it was evaluated whether or not there would be any trouble in opening the fibers. The results are also shown in Table 2 below.

[0025]

[Table 2]

[0026]

[Examples 8 to 11, Comparative Examples 2 and 3] Solvent deposition was carried out under the same conditions as in Example 1 (3.8% SO was attached), and drying was performed at 60°C for 120 minutes. The solvent-coated acrylic fibers were mixed with normal acrylic at a mixing rate of 80% using a cotton mixing machine, and after carding, they were drawn three times and the gel was changed to obtain the desired gel, as shown in Table 3 below. The density of the resulting pen nib was adjusted as shown in . Next, this web was attached to a mouthpiece with an inner diameter of 5 mm (surface temperature 2
The material was heat-treated by passing through a temperature of 30° C.) and processed into a rod shape. Then, it was cut into a predetermined length and one end was polished to produce a nib core for a writing instrument. A writing instrument was manufactured using the pen nib obtained in this way, and it was evaluated whether or not the ink would fade with use. The results are also shown in Table 3 below.

[0027]

[Table 3]

[0028]

[Examples 12 and 13, Comparative Example 4] In addition, the mixing ratio of the solvent-coated acrylic fiber was changed as shown in Table 4 below, and the other processing conditions were the same as in Example 8 above. I got the core. Then, the compressive strength of these pen nib cores was measured. The results are also shown in Table 4 below.

[0029]

[Table 4]

[0030]

[Effects of the Invention] As described above, the writing instrument nib core of the present invention has no impurities in the interfiber spaces and does not use resin as a binder, so the ink does not deteriorate due to residual resin. . Therefore, the fluidity of the ink is not hindered, and ink smearing is less likely to occur when writing. In addition, appropriate strength and hardness can be ensured depending on the application and shape. Further, according to the method of the present invention, there is no need for a solvent recovery step, and the writing instrument nib core can be manufactured with high production efficiency and at low cost.

Claims (3)

[Claims] 1. A writing instrument nib core made of a fiber aggregate heat-sealed to a density of 0.15 to 0.75, wherein 50% by weight or more of the fiber aggregate is composed of acrylic fibers. A writing instrument pen nib characterized by: 2. A step of attaching 0.5% by weight or more of a solvent for acrylic fibers to acrylic fibers, and a step of creating a fiber bundle in which 50% by weight or more of the solvent-coated acrylic fibers are uniformly mixed. A method for producing a nib core for a writing instrument, comprising the step of passing the fiber bundle through a guide maintained at 200° C. or higher and simultaneously pressurizing and heat-sealing the fiber bundle. 3. A step of adhering 0.5% by weight or more of an acrylic fiber solvent to the acrylic fiber, a step of producing a sliver in which 50% by weight or more of the solvent-coated acrylic fiber is uniformly mixed; The sliver is passed under pressure through a nozzle whose surface temperature is set to 200°C or higher to heat-fuse the solvent-coated acrylic fibers to each other to form a rod shape, and the rod-shaped body is cut into a predetermined length. A method for manufacturing a pen nib for a writing instrument, comprising the step of: forming the nib into a pen nib shape.