JPH02199B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink storage body for a writing instrument. Conventionally, this type of ink absorber has been made by combining fiber bundles of synthetic fibers such as polyester, nylon, acrylic, vinylon, and polyethylene with melamine, epoxy,
Ink for writing is impregnated with an initial condensate of thermosetting resin such as phenol, compressed, and heated to harden the impregnated thermosetting resin and bind and mold the fibers. When these thermosetting resins are used in occluding bodies that are supposed to allow liquid materials to flow smoothly, it is difficult for the thermosetting resin to adhere to the fiber bundles evenly in all parts, resulting in problems such as ink leakage and proper ink occlusion. The drawback was that the capillary structure where this was carried out was incomplete, resulting in severe variations in the amount of ink flowing out. In order to improve this defect, for example, a manufacturing method was developed in which a sliver obtained by mixing multiple types of fibers with different melting points was covered with a resin film having a similar melting point and heat-sealed. −
As described in Publication No. 37571, in the case of multiple types of fibers with different melting points, there are large differences in fiber strength and elongation, differences in crimp conditions, etc., and therefore uniform and sufficient It is difficult to set spinning conditions that produce a mixed wool effect, and it is also difficult to obtain a uniform blend of multiple types of fibers, resulting in difficulty in obtaining a uniform capillary structure. In addition, an adhesive solution is applied to a continuous fiber bundle in which the fibers are aligned in the axial direction, and then the liquid is squeezed and the solvent is dried and removed to bind and solidify.Finally, the outer periphery of the fiber bundle is covered with a polymer film. The manufacturing method for the ink storage body was published in 1974.
Although it is described in Japanese Patent No. 16963, it has the disadvantage that the process of wrapping a polymer film into a tape and then joining the tapes at their overlapping parts cannot be sped up, and also has a high rate of defective products, making it uneconomical. Ta. The present inventors completed the present invention as a result of intensive research to eliminate such defects. The purpose of the present invention is to have a high ink utilization rate, prevent blurring,
To provide an ink storage body for a writing instrument which has excellent writing properties without blurring and is easy to assemble. In the present invention, the fibers are aligned in the axial direction, and at least
An ink for a writing instrument consisting of a fiber bundle of crimped acrylic fibers made of a polymer containing 50% by weight of acrylonitrile, in which a portion of the acrylic fibers are adhered by gelation of the fibers themselves. This applies to the occlusion body. The crimped acrylic fiber applied to the present invention may be a commercially available acrylic fiber, for example, containing 50% by weight, preferably 80% by weight or more of acrylonitrile, and if necessary, methyl acrylate, methyl methacrylate, etc. An acrylic acid derivative or an acrylic polymer copolymerized with a monomer containing a sulfonic acid group is spun and then crimped. Acrylic fibers preferably have a crimp count of 5 to 20 crimps/inch, particularly 6 to 14 crimps/inch, and have a fineness of usually 1 to 20 denier, preferably 2 to 10 denier. Also, the fiber length of the fiber bundle is 30
Preference is given to slivers consisting of fibers of up to 200 mm, especially 8 to 110 mm. Therefore, in the ink absorbing body of the present invention, the gaps between the fibers are distributed almost uniformly, and in particular, the gaps between the fibers are not too large.
In addition, it is necessary to have a substantially uniform capillary structure so that the capillary structure is not too small, and for this purpose, it is necessary to avoid close contact between fibers. In this respect, when crimping without crimp is used, the fibers tend to stick partially to each other, making it difficult to form an appropriate capillary gap. Therefore, the fibers used must be crimped, and when such fibers are used, it is difficult for the fibers to adhere to each other, and it is easy to obtain excellent ink storage properties and ink fluidity. The crimp may be applied physically or mechanically in the latter stage of the spinning process, or it may be a structural crimp that utilizes the latent shrinkage force of the fibers. Organic solvents applicable to the present invention include amide-based,
A large number of compounds can be listed, such as nitrile, sulfone, sulfoxide, nitro, and carbonate compounds; for example, amide compounds include dimethylformamide, dimethylacetamide, etc.
In addition, nitrile compounds include succinonitrile, malonitrile, etc., sulfone compounds include nitramethylene sulfone, ethylmethyl sulfone, etc., and sulfoxide compounds include dimethyl sulfoxide, nitro compounds, etc. Examples of compounds include nitromethane, and examples of carbonate compounds include γ-butyrolactone and ethylene carbonate. These solvents can also be used as a mixture or as a solution such as an aqueous solution. The dissolution behavior of these various solvents for acrylic fibers is not necessarily the same, but is influenced by the chemical characteristics of each solvent, and the temperature dependence or solubilization temperature varies widely. Therefore, for the present invention, any of these organic solvents can be used as long as the processing conditions are selected, but in this case, the chemical properties of each organic solvent for acrylic fibers, especially Taking temperature dependence into consideration, it is important to select the immersion bath temperature at a temperature within which the fibers do not yet swell. Therefore, for consolidation and drying after impregnation and squeezing, the fibers are exposed to a higher temperature atmosphere, but it is only at this point that the organic solvent swells the fibers. - The drying/consolidation temperature must be chosen at such a temperature that the dissolution phenomenon begins. Tetramethylene sulfone is particularly suitable as a solvent for use in the present invention in terms of workability and quality of the product obtained. The amount of the organic solvent used in the present invention needs to be appropriately increased or decreased depending on the hardness of the occluding body to be manufactured, and the hardness also depends on the size of the writing instrument, that is, the thickness of the occluding body, and the connection with the nib body. It is also related to the format, or the viscosity and fluidity of the ink used. Therefore, in accordance with such hardness requirements, the amount of the pure organic solvent deposited on the fiber is usually appropriately selected from the range of 1 to 30% by weight, and most preferably from 7 to 15% by weight. In addition, when used as an organic solvent solution, the concentration of the organic solvent may be increased or decreased as appropriate according to the subsequent squeezing rate of the squeezing device. The content may be adjusted to 30% by weight, preferably 7 to 15% by weight. The ink storage body of the present invention is formed by aligning fiber bundles, at least a part of which is adhered by gelation of the acrylic fibers used. The degree of adhesion varies depending on the denier of the fibers used, fiber length, number of crimps, gelation of the sliver, the density of the intended occlusion body, its type, etc., but at least part of it retains the shape of the fibers. . Next, a method for manufacturing the ink storage body of the present invention will be described. Acrylic fibers with crimp have a fiber length of 30 to 200
The cut cotton of mm size is carded and drawn into fiber bundles aligned in the axial direction, and then molded. Depending on the fiber length of the acrylic fiber, short spinning methods such as the so-called 2-inch spinning method and 3-inch spinning method, or long spinning methods such as worsted spinning and semi-worsting spinning can be used as the carding and kneading methods. Worsted sliver is most preferred.
The gel of the sliver can be determined appropriately depending on the type of the intended ink storage body, but it is usually 1 to 100g/
m is used, and in the case of the present invention, the density is usually
It is 0.1 to 0.6 g/cm ³ . Next, a soluble organic solvent is applied between the fibers by impregnation etc. to the acrylic fibers forming the fiber bundle made by aligning the slivers thus obtained, to partially dissolve the fibers, and then It is molded into the desired shape by heating while compressing it. Compression and heating are usually performed by passing through a high-temperature tube at a temperature of 200°C or higher, which evaporates the organic solvent on the surface layer of the fiber bundle and causes adhesion between the fibers that are in contact with each other. In addition to inducing softening due to high heat, the fibers in the surface layer are crushed, so that the flattened fibers are piled up, a coating layer is provided around the outer surface of the cylindrical body, and it is molded into a desired external shape. The contact time of this treatment is usually 0.05~
A short time of about 0.3 seconds, and the temperature is normal.
A temperature range of 200°C to 350°C can be used, but preferably a contact time of 0.1 to 0.2 sec and a treatment temperature of 250 to 280°C. The fiber bundle formed into a desired shape by heating is then dried to remove the solvent. Drying may be carried out at a temperature that is at least the dissolution temperature of the organic solvent used for the acrylic fibers, and as mentioned above, in the case of tetramethylene sulfone, which is considered to be the most preferred, it may be at least 60°C. Drying involves forcing hot air into the center layer of the fiber bundle to evaporate the organic solvent inside the gelled fibers and fuse the fibers in the areas that are in contact with each other.
A temperature range of 80°C to 90°C and a processing time of 3 to 7 minutes are most preferable, although it varies depending on the thickness and density of the desired molded product. It is better to keep the drying temperature as low as possible.
This is preferable because it is economical and prevents inadvertent heat damage to the fibers. The time required for drying may be increased or decreased depending on the outer diameter of the ink storage body, the required hardness, and the speed of passage through the cylindrical molding nozzle. In short, it is sufficient that the necessary and sufficient drying and solidification are performed up to the central core of the ink storage cylinder, and there is no need to spend more time than necessary for drying. The hard coating layer on the outer peripheral surface of the obtained ink storage body forms a slight gap between the writing instrument body and the ink storage body when the ink storage body is later installed in the writing instrument main body cylinder, and this creates a small gap between the writing instrument body and the ink storage body. When press-fitting ink, it serves as a leakage path for the air that should replace the injected ink, and at the same time, in the completed writing instrument,
When drawing characters, etc., it is also advantageous because the air that is to be replaced with the ink flowing onto the paper is conducted. Since the ink storage body of the present invention swells and dissolves the fibers themselves without using a thermosetting resin, unreacted residues of hardening agents, processing agents, etc. do not settle inside the fibers, and It is far superior to hardeners in that the treatment agent is evenly distributed into the pores within the fibers, and in short, it is far superior to hardeners, and in short, it is not only capable of deteriorating the quality of the ink due to chemical reactions with treatment agent residues, but also eliminating pores caused by uneven adhesion. It is possible to provide an occluding body that can stably supply liquid ink without being unable to write due to ink clogging caused by non-uniformity. The ink storage body for writing instruments according to the present invention has such features and is easy to use, so it can be used for fine, medium, and bold characters, or for oil-based ink, water-soluble ink, or with a hard nib. It can be used in a wide range of writing instruments, regardless of whether it is a writing instrument with a brush-type nib or a writing instrument with a brush-type nib. Furthermore, the ink storage body for writing instruments of the present invention has various features, one of which is that the capillary structure between the fiber bundles is uniform, so that the permeation and storage functions are uniform, and ink leaching always occurs smoothly. Another reason is that thermosetting resins and various chemicals such as curing accelerators, catalysts, and stabilizers are not used at all, so there is a risk of chemical reactions between these unreacted residues or additives and the ink. This is extremely advantageous in that there is no risk of deterioration in the quality of the ink. Examples of the present invention are listed below. Example 1 A mechanically crimped acrylic fiber with a fineness of 3 denier and a fiber length of 102 mm bias cut was carded and kneaded in the same process as normal worsted spinning to produce a 40 g/m sliver. This sliver is immersed in a 10% acetone solution of tetramethylene sulfone, squeezed with a roller (liquid content 100%), passed through a focusing nozzle, and run through a molding cylinder whose surface temperature is maintained at 20°C. Organic solvents (tetramethylene sulfone and acetone) on the sliver surface fiber layer are evaporated and removed, and a cured film is created. Subsequently, it was passed through a dryer circulating hot air at 80°C to evaporate and remove all remaining organic solvent, and finally passed through a cutter to obtain a cylindrical ink storage body with a diameter of 15 mm and a length of 100 mm. The resulting ink absorber was fitted into the main body of a writing instrument with an inner diameter of 16 mm, and oil-based ink was filled in. The workability, writability, and ink utilization were compared with conventional products, and the results are shown in Table 1. Obtained. 【table】

Claims (1)

[Scope of Claims] 1 Consists of a fiber bundle of acrylic fibers aligned in the fiber axis direction and having crimps made of a polymer containing at least 50% by weight of acrylonitrile; An ink-absorbing body for writing instruments in which a portion of the fibers are glued together by gelation. 2. The storage body according to claim 1, wherein the fiber bundle is a sliver. 3. The occlusion body according to claim 1, wherein the weight of the occlusion body is 1 to 100 g per meter (converted). 4. The occluding method according to claim 1, wherein the occluding body has a density of 0.1 to 0.6 g/cm ³ .