JPH0216705B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ink-impregnated body. More specifically, the present invention relates to ink-impregnated bodies such as ink rolls and ink pads that are tough, have excellent abrasion resistance and dimensional stability, and have good elasticity and porosity. Traditionally, ink-impregnated bodies such as ink rolls and ink pads have been made by filling polymer powders such as acrylonitrile-butadiene rubber, polyurethane, and nylon into molds and heating and sintering them at high temperatures to form porous bodies with micropores. However, it is well known that the porous body is then manufactured by a so-called sintering method in which the porous body is impregnated with ink. However, in the case where polymer powders as mentioned above are simply integrated by sintering, a large amount of heat is required for sintering, and it is difficult to obtain the desired porosity, and it is difficult to achieve the desired ink impregnation rate. This method has the disadvantage that it is not possible to produce a porous body that is strong and has appropriate elasticity and has excellent ink exudation properties. It is also known that inorganic or organic fine powder particles are coated with thermoplastic elastomer on the entire surface and then sintered to obtain a porous body, which is then impregnated with ink (Japanese Patent Application Laid-Open No. (See Publication No. 53-23357). However, this type also had the same drawbacks as the previous type, and the vacancy rate was still low. The present invention has been completed in order to eliminate the above-mentioned drawbacks, and its gist is that inorganic powder particles are formed by a large number of fine particles of an organic elastic material attached to the outer peripheral surface at intervals. The present invention is an ink-impregnated body in which a continuous porous body is formed by using the organic elastic material as a framework material, and the framework materials are mutually fixed by fine particles of the organic elastic material, and the ink is impregnated with the continuous porous body. The ink-impregnated body of the present invention has a structure in which inorganic powder particles are fixed to each other by organic elastic material fine particles, and has superior toughness, abrasion resistance, and porosity compared to conventional ones, and can absorb ink. It has good durability for replenishing ink ribbons or type. Inorganic powders used in the present invention include, for example, soft inorganic powders with excellent compression properties such as carbon black, calcium carbonate, and calcium sulfite, hard inorganic powders with excellent tensile strength such as silica, aluminum silicate, and clay, and titanium powders. Potassium acid, wollastonite, talc, mica, etc., which increase tensile strength and compressive properties, can be mentioned. Examples of materials for the organic elastic material fine particles in the present invention include thermoplastic resins, thermoplastic rubbers, thermosetting resins, and reactive liquid rubbers. Examples of the thermoplastic resin include polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyamide, and polyamide copolymer. Examples of the thermoplastic rubber include polyurethane and acrylonitrile-butadiene rubber. These thermoplastic resins and thermoplastic rubbers are attached in a molten state. Examples of thermosetting resins include polyurethane, epoxy resins, unsaturated polyesters, and diallyl phthalate resins, and examples of reactive liquid rubbers include liquid urethane rubber, liquid butadiene-styrene rubber, and liquid acrylonitrile-butadiene rubber. , liquid chloroprene rubber, etc. Both of these thermosetting resins and reactive liquid rubbers are liquefied or liquefied at relatively low temperatures. Next, a method of manufacturing a skeleton material by attaching organic elastic material fine particles to the outer surface of the inorganic powder particles and a method of molding the obtained skeleton material will be explained. The organic elastic material is in a liquid state and is mixed with the inorganic powder so that it adheres to the surface of the inorganic powder particles with some spacing, and a large number of fine organic elastic material particles adhere to the outer surface of the inorganic powder particles at intervals. Obtain the framework material for the structure. FIG. 1 is a schematic cross-sectional view showing an example of a skeleton material obtained in this manner, in which a large number of organic elastic material fine particles 2 are attached to inorganic powder particles 1 with gaps between the particles. This makes it possible to greatly increase the porosity of the resulting porous material, and furthermore, by appropriately changing the amount of organic elastic material mixed, it is possible to obtain a porous material with a desired porosity. The advantages are demonstrated. The inorganic powder particles 1 preferably have a particle size of 5 to 150 μm and are spherical or nearly spherical (for example, ellipsoidal). The framework material in which the organic elastic material fine particles 2 are attached to the inorganic powder particles 1 in this way is uniformly filled into the mold by a pressureless filling method using a vibrator, and the porous material is sintered by heat treatment with hot air. You can gain a healthy body. Thus, the present invention has the advantage that the amount of heat required for sintering can be extremely reduced. The organic elastic material is attached to the surface of the inorganic powder particles with gaps between the particles, and the framework materials are bonded to each other by thermoforming and impart elasticity. The organic elastic material may be mixed with an inorganic powder in a liquid state and then filled into a mold, or the materials may be placed in a mold and mixed together. When a thermoplastic resin is used as the organic elastic material, the thermoplastic resin is heated and molten and mixed with an inorganic powder, and then cooled and solidified in a mold. In addition, liquid thermosetting resin undergoes polycondensation by heating and forming in a mold.
After being cured, the reactive liquid rubber is likewise crosslinked and cured by heat treatment in the mold. The blending amount of the organic elastic material will be changed as appropriate depending on the type of material used, but it should be 10 to 50% (wt%, same hereinafter), especially 20 to 35% of the total amount of inorganic powder and organic elastic material. % is preferred. In order to improve the adhesion between the inorganic powder and the organic elastic material, titanate coupling agents such as isopropyl tri(dioctyl phosphate) titanate and isopropyl triisostearoyl titanate, as well as silane coupling agents, zirconate coupling agents, and aluminum are used. It is preferable to use a coupling agent such as a calcium-based coupling agent or a calcium-based coupling agent. Such coupling agents improve the surface adhesion of inorganic powders,
It imparts strong adhesive strength, acts as a viscosity modifier for liquid organic elastic materials, and also functions as a curing catalyst. The shape of the inorganic powder in the present invention is spherical,
Various shapes such as fibrous shape and plate shape (flake shape) are preferably employed. For example, if the inorganic powder is approximately spherical, the powder particles in the mold are arranged as shown in Figure 2 by the non-pressure filling method using a vibrator (for example, the parallel rhombus filling method) as described above. However,
In the present invention, as shown in FIG. 1, the organic elastic material fine particles 2 are attached to the surface with appropriate spacing, resulting in an arrangement as shown in FIG. 3, which greatly increases the porosity. can do. Incidentally, in the arrangement shown in FIG. 2, the porosity is about 25% by volume, but in the arrangement shown in FIG. 3, it is possible to increase the porosity to 60-75% by volume. If the inorganic powder is in the form of short fibers (for example, monocrystalline fibers such as potassium titanate or wollastonite, with an aspect ratio of 10 to 50:1 and a diameter of 15 to 30μ), the strength will be increased uniaxially when blended. However, by filling the mold without orientation, the void can be enlarged.
In addition, inorganic short fibers include organic short fibers (for example, aromatic polyamide fibers such as Kevlar fiber manufactured by DuPont),
It is preferable to use a mixture of carbon fibers, graphite fibers, polyester fibers, etc., in order to increase toughness. In addition, plate-like powder (such as kaolin and talc, typically mica, which has a width
When the flake aspect ratio is 1.4 to 4μ and 40μ or less, usually 2 to 3μ, and the flake aspect ratio is 4:1 to 100:1, it is also non-oriented or uniaxially oriented, as in the case of short fibers. Just fill it into the mold. Furthermore, by using inorganic powders having each of these shapes in combination, the porosity can be increased. In the present invention, after filling a mold with a framework material in which organic elastic material fine particles are attached to inorganic powder particles, the organic elastic material fine particles are rapidly melted and sintered, and either cooled and solidified or heated and hardened. In order to shorten the processing time, it is preferable to preheat by far-infrared irradiation or the like. After heat molding, the resulting porous body can be treated with alcohol, acetone, benzene, etc. to dissolve the organic elastic material.
Micropores are formed by removing or shrinking the thin film on the surface of the porous material by immersing it in a mixed solution of a solvent such as xylene or dimethylformamide and a non-solvent such as water, or preferably by contacting it with the magnetism of these solvents. It is preferable to open it and aim for uniform porous formation. For impregnating the thus obtained porous body with ink, an ink impregnation method used for ordinary ink pads and ink rolls can be suitably employed. As described above, the present invention uses inorganic powder etc. to create a framework material having a structure in which fine particles of an organic elastic material are attached to the outer surface of inorganic powder particles which can take various shapes with gaps between the particles. It is firmly bonded by short-time heating and pressure forming under much lower temperature conditions than normal sintering conditions, and has the toughness, wear resistance, and dimensional stability of inorganic powder. It has the excellent advantage of being able to easily produce a porous body having excellent properties such as, and having cavities of a size suitable for an ink roll or an ink pad. Next, the present invention will be explained with reference to Examples. Example 1 While stirring spherical calcium sulfite powder with an average particle size of 5 μm in a high-shear stirrer, molten nylon 66 was atomized at a ratio of 20% of the total amount to the outside of the calcium sulfite powder particles. The droplets were deposited on the surface with gaps between them and then cooled. The obtained adhering calcium sulfite powder was struck and vibrated with a ribbon blender to sufficiently loosen the agglomerated powder, and then a predetermined amount was filled into a mold with a diameter of 20 mmφ and a length of 40 mm, and the powder was heated under pressure. It was heat-molded at 200°C for 5 minutes and then allowed to cool to obtain a porous body. This material was impregnated with oil-based ink to obtain an ink-impregnated body. Example 2 While stirring spherical calcium sulfite powder with an average particle size of 10μ in a high-shear stirrer, liquid polyurethane [room-temperature curable polyurethane resin ADAPT60L]
Liquid polyurethane (manufactured by Kokusai Chemical Co., Ltd.) containing 10 parts by weight and 3 parts by weight of a curing agent (liquid isocyanate) was poured into a thread at a ratio of 15% of the total amount to the outer surface of the calcium sulfite powder particles. The droplets were deposited with a gap between them. The resulting adhered calcium sulfite powder was struck and vibrated with a ribbon blender to sufficiently loosen the agglomerated powder, and then a predetermined amount was filled into a mold with a diameter of 25 mmφ and a length of 50 mm, and heated at 100°C.
A porous body was obtained by heating and molding for 5 minutes. This material was impregnated with oil-based ink to obtain an ink-impregnated body. Example 3 A reactive liquid rubber composition [Hiker CTBN 1300
(Nitrile rubber manufactured by Gutsudoritsuchi Chemical Co.)
143 parts by weight, 24 parts by weight of bisphenol A (chain extender), epoxy resin RA 10A (manufactured by Kokusai Chemical Co., Ltd.)
A composition containing 100 parts by weight of epoxy resin curing agent RA 10B (manufactured by Kokusai Chemical Co., Ltd.)]
was injected at a rate of 10% of the total amount using a quantitative mixing and dispensing machine, and the droplets were deposited on the outer surface of the calcium sulfite powder particles with gaps between the droplets. The obtained adhered calcium sulfite powder was prepared in Example 1.
In the same manner as above, it was loosened with a ribbon blender, filled into a mold, gelled at 40°C for 7.5 minutes, and further cured at room temperature for 30 minutes to obtain a porous body. This material was impregnated with oil-based ink to obtain an ink-impregnated body. Comparative example Filled with nylon 6 powder with an average particle size of 65μ,
After preheating and forming under pressure at 160℃ for 10 minutes,
The porous body obtained by firing in a hot atmosphere at 260° C. for 3 minutes was cooled and dried, and then impregnated with oil-based ink to obtain an ink-impregnated body. The toughness, abrasion resistance, and porosity of each ink-impregnated body obtained in Examples 1 to 3 and Comparative Example were examined. The results are shown in Table 1. The test items for each test item in Table 1 are as follows. (1) Toughness Tensile strength and elongation were based on the tensile test method described in JIS K 6301. In addition, the tensile stress was measured on the test piece (outer diameter 44.6 mmφ, inner diameter
36.6mmφ, length 57.5mm) by measuring the tensile load when 50% elongation was applied. (2) Wear rate The degree of wear was measured in accordance with British standard BS 903 part A9C method. In other words, a load of 1.4 kg (3 pounds) was applied to a sample (thickness 10 mm, width 14 mm) using an Akron type abrasion tester, and the polishing disk was rotated with an inclination angle of 15 degrees between the sample and the rotating surface of the polishing disk. The wear rate was determined by measuring the abrasion weight. (3) Vacancy rate The vacancy rate was calculated using the following formula. (1-W/d×V)×100 W: Weight of porous body not containing ink V: Volume of porous body d: Specific gravity of porous body constituent material

[Table] In addition, the ink-impregnated bodies obtained in Examples 1 to 3 were excellent in exudation of the ink contained in the fine pores, and were particularly excellent in ink exudation under slight pressure.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view showing an example of a framework material in which organic elastic material fine particles are attached to the outer surface of inorganic powder particles in the present invention, and Fig. 2 shows an arrangement of spherical inorganic powder particles in a mold. The schematic explanatory drawing, FIG. 3, is a schematic cross-sectional view showing the arrangement of the framework material shown in FIG. 1 within the mold. (Symbols in drawings), 1: inorganic powder particles, 2: organic elastic material fine particles.

Claims (1)

[Scope of Claims] 1. Inorganic powder particles having a large number of fine particles of an organic elastic material attached to the outer circumferential surface at intervals are used as a skeleton material, and the fine particles of the organic elastic material make the skeleton material An ink-impregnated body is formed by impregnating ink into a continuous porous body formed by mutually fixed porous bodies. 2. The ink-impregnated body according to claim 1, wherein the inorganic powder has a particle size of 5 to 150 μm. 3. The ink-impregnated body according to claim 1 or 2, wherein the inorganic powder is spherical or nearly spherical. 4. The ink-impregnated body according to claim 1, wherein the inorganic powder is in the form of short fibers. 5. The ink-impregnated body according to claim 4, further comprising organic short fibers as a skeleton material. 6. The ink-impregnated body according to claim 1, wherein the inorganic powder is plate-shaped. 7. The organic elastic material is at least one selected from the group consisting of thermoplastic resin, thermoplastic rubber, thermosetting rubber, thermosetting resin, and reactive liquid rubber.
Claims 1, 2, and 3 that are species
The ink-impregnated body according to item 1, 4, 5, or 6.