JPS6140199B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a fiber bundle of higher quality by completely covering the periphery and both cut end surfaces of a fiber bundle, which has been previously formed by a conventional method, with an open-cell foam. Conventionally, fiber bundles, which are made by gathering fiber tows or slivers and forming them into various shapes such as rods and plates, are used as the nib of a writing instrument generally called a felt-tip pen.
It is widely used to adjust the absorption and movement of liquids, such as cores for ink storage, perfume storage bodies, and nozzle valve adjustment for gas lighters. Various methods are employed for manufacturing general fiber bundles, such as an adhesive method, a coating method, and a welding method. A common problem when using these fiber bundles is that, even though the fiber bundles have sufficient ability to store liquid, especially when used for applications that absorb and store liquids, such as ink absorbers for felt-tip pens, Due to other factors, such as dropping, high temperatures, and leaving the product upside down,
If the fiber bundle is placed under harsh conditions, it is common to keep the liquid filling amount at about 70% to 50% of the fiber bundle's liquid storage capacity in consideration of overflow of the stored liquid. That is, to take the ink absorber of a felt-tip pen as an example and explain it in detail, the porosity of a fiber bundle that can be used as an ink absorber is 70% to 70% of the apparent volume of the fiber bundle.
It is about 90%. Considering only writing with a felt-tip pen, the larger the amount of ink filled, the greater the amount of writing, so the state where all the air in the pores of the fiber bundle, which is an ink absorber, is replaced with ink, that is, the state of saturated ink amount. shows the maximum amount of writing possible as a writing instrument. However, a writing instrument assembled in this manner is susceptible to ink overflow due to the external shock, and the ink leaking from the inside flows out to the outside, making it practically unusable as a writing instrument. For this reason, the amount of ink is generally kept to a level that allows the fiber bundle's liquid retention capacity to withstand external shocks. In other words, the amount of saturated ink is kept at 70% to 50%. However, according to the present invention, a fiber bundle is immersed in a solution prepared by dissolving an organic synthetic polymer in a solvent, or after the solution is coated on the outer periphery of the fiber bundle, solvent extraction is performed with another solvent. As a result, an extremely fine open-pore foam film is formed on the surface of the fiber bundle, so when this is used as a liquid storage material, even if the amount of liquid stored is the saturated amount of the liquid used. No overflow of liquid due to an external shock occurs, and the space in the fiber bundle with a preset porosity is filled 100% with liquid, thus solving the above-mentioned conventional problems. The gist of the present invention is to dissolve an organic synthetic polymer in one or more first solvent systems, immerse a fiber bundle in the solution, or apply the solution, and then dissolve the fiber bundle in a first solvent system. Pour into the second solvent system. This second solvent system does not dissolve the organic synthetic polymer, but it is a system of one or more solvents that are mutually soluble with the first solvent system, and the fibers introduced into this solvent are The first solvent system in the organic synthetic polymer layered on the surface of the fiber bundle is dissolved and extracted into the second solvent system, and the organic synthetic polymer on the surface of the fiber bundle is dissolved in the introduced solvent system. It becomes an open-cell foam while undergoing substitution. Examples of solvents used in carrying out the present invention are shown in the table below.

[Table] The quality characteristic when the fiber bundle is coated with open cell foam is the increase in the amount of filling liquid. There are other major features covered with. That is, when the liquid moves away from the fiber bundle, the space occupied by the liquid must be immediately replaced with air to ensure smooth movement of the liquid. Since the open cell foam of the present invention is a foam having very fine cells, air is sucked in as the liquid moves, and the liquid and air are replaced very smoothly. The methods shown in FIGS. 1 and 2 are conceivable as methods for covering fiber bundles produced by conventional methods with open-cell foam. That is, Fig. 1 shows a case in which a foam layer 2 is coated on the entire outer periphery of a fiber bundle 1 in which the fibers are dot-bonded or welded together with resin, and Fig. 2 shows a case in which a foam layer 2 is coated on the entire outer periphery of a fiber bundle 1 with resin film or cellophane paper. This is a covering method in which fibers are bundled with a plastic film 3 to form a fiber bundle. In this case, only the cut surfaces are covered with a foam layer 4.
All you have to do is cover it with That is, according to the present invention, the entire outer periphery or both end faces of the fiber bundle is covered with an open-cell foam layer, so even when ink or other liquid is sucked up to the full liquid retention capacity (saturated amount), it is difficult to handle the fiber bundle. There is no risk of liquid leakage (or during use). Therefore, it becomes possible to store a larger amount of liquid in the same volume, which has the effect of increasing the usage amount of the same substance. Furthermore, since the liquid retention property is improved, there are no accidents during use or handling, which has the effect of improving quality. Next, examples of the method of the present invention will be described. Example 1 60% polyester and 40% polypropylene in a solution of 35% polyacrylonitrile (for injection molding) as an organic synthetic polymer dissolved in 50% dimethylformamide and 15% acetone as the first solvent.
A fiber bundle (5.2mm
After immersing a sample (diameter x 92 mm length), it was immediately taken out, placed in water to replace the solvent, and then dried. When measuring the amount of saturated ink in this fiber bundle,
Since it was 1.8 cc, I filled it with that amount, assembled it as a writing instrument, and conducted various environmental acceleration tests, but no ink overflow was observed. Example 2 The fiber bundle used in Example 1 was immersed in a solution of 25% thermoplastic polyurethane (for injection molding) and 75% dimethylformamide, then taken out and placed in water to replace the solvent. After drying, it was filled with 1.8 cc of ink, assembled into a writing instrument, and subjected to various accelerated environmental tests, and no ink overflow was observed. Example 3 Polyester fiber bundles (6 mm diameter x 80 mm
(length) and immediately soak both ends in 50% methyl alcohol.
After replacing the solvent by placing it in a mixed solution of 50% isopropyl alcohol, it was dried and filled with 2.1 cc of ink, which was then used as a writing instrument. When the same test as in Example 1 was conducted, no ink leakage was observed. Ta.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of another embodiment. 1... Fiber bundle, 2, 4... Open cell foam layer.

Claims (1)

[Claims] 1. A fine open-cell foamed layer is provided on the outside of the fiber bundle, and the open-cell foamed layer is made by adhering a solution formed by dissolving an organic synthetic polymer in a first solvent to the fiber bundle. A fiber bundle for liquid storage, characterized in that it is formed by extracting the first solvent with a second solvent. 2. The liquid storage fiber bundle according to claim 1, wherein the open cell foam layer is layered around the entire outer periphery of the fiber bundle. 3. The liquid storage fiber bundle according to claim 1, wherein the fiber bundle is bundled with a liquid-impermeable film, and an open cell foam layer is layered only on both end faces thereof. 4. The liquid storage fiber bundle according to claim 3, wherein the liquid-impermeable film is a synthetic resin film or cellophane paper.