JPH0572271B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a porous stamp having fine continuous pores.

(Prior Art) Conventionally, as a method for manufacturing this type of porous stamp, for example, a thermoplastic elastomer containing a hydrophilic group was used alone, or a mixture with a thermoplastic elastomer not containing a hydrophilic group, or a thermoplastic elastomer containing a hydrophilic group or containing a hydrophilic group was used. An oil-in-water type product obtained by dissolving a mixture of a thermoplastic elastomer and a hydrophilic material in a solvent that is soluble in the thermoplastic elastomer but whose boiling point is 120°C or less, and dispersing water in the solution. Alternatively, a water-containing porous body obtained by selectively removing only the solvent from a water-in-oil dispersion is pulverized as it is, or the powder obtained by pulverizing after drying is filled into a mold and sintered.
It has become publicly known from Publication No.-35554 and the like.

(Problems to be Solved by the Invention) However, in the porous stamp obtained by this method, the porosity of the type part protruding from the lower surface and the ink supply part of the upper layer is constant, so the shape of the type part tends to change. If the overall porosity is reduced in order to prevent distortion and distortion, the porosity of the ink supply section will also be reduced, reducing the ink content and lowering the rate of ink supply to the printed area, which may cause the stamp to become blurred. In addition, in order to avoid such a situation, the amount of ink supplied to the type area is increased, which increases the overall porosity of the type area. This caused problems such as the impression of the seal made by the type part became unclear.

(Means for solving the problems) The present invention chemically crushes a thermoplastic elastomer containing a hydrophilic group, a mixture of thermoplastic elastomers not containing a hydrophilic group, or a mixture of a thermoplastic elastomer and a hydrophilic material. Alternatively, the fine powder material obtained by physically pulverizing is subjected to sintering by setting the temperature, pressure, amount of powder, and time so as not to lose its elasticity and microporosity at the sintering temperature. Then, the sheet-like sintered form is inserted between a female mold for characters and a male mold for characters, and the sintered form is placed in a predetermined shape. A thin film for the surface layer that exhibits an unevenly deformed shape along the mold surface is constructed by performing hot press processing in which the material is softened and deformed while maintaining its porosity, and cooling press processing in which it is rapidly cooled in the softened and deformed state. Furthermore, after removing the male mold for characters, the female mold for characters with the thin film for the surface layer still in place is filled with the above powder material to a predetermined appropriate amount, and on top of this filled powder material, an ink occluding material is added. An ink absorber made of a suitable porous open pore sintered foam or porous open open crosslinked foam is placed and hot pressed into the ink absorber, filling powder material, or thin film for the surface layer. The powder material and the thin film for the surface layer are applied at a pressure temperature and time set so as to maintain a predetermined porosity, and then rapidly cooled by cooling press processing to form the ink absorber, filled powder material, and surface layer. The present invention attempts to solve these problems by providing a method for manufacturing a porous stamp having continuous pores, which is characterized by combining thin layers.

(Example) First, a thermoplastic elastomer containing a hydrophilic group alone, a mixture of a thermoplastic elastomer not containing a hydrophilic group, or a mixture of a thermoplastic elastomer and a hydrophilic material were obtained by pulverizing using a glider. Temperature 150 between 150 micron powder material
℃ for 3 minutes at a compression ratio of 65% to produce a sheet-like sintered foam 1 with a porosity of 35% and a thickness of 1 mm.
Configure.

Next, the sheet-like sintered form 1 is inserted between the female mold 2 for characters and the male mold 3 for characters, and the sintered foam 1 is softened while maintaining the above porosity. The thin film 4 for the surface layer, which exhibits an unevenly deformed shape along the mold surface, is formed by performing hot press processing for deformation and cooling press processing for rapid cooling in a softened and deformed state.

Furthermore, after removing the male letter mold 3, the female letter mold 2 with the surface layer thin film 4 still in it is filled with the powder material to a height of approximately 5 mm, and the filled powder material 5 is An approximately 2 mm thick ink storage body 6 made of cross-linked urethane foam with a porosity of 65% is placed on top of the ink storage body 6, the filler powder material 5, the thin film 4 for the surface layer, and the hot plates 7, 7'. Compressibility of cross-linked urethane foam is 10%, compressibility of filled powder material is 10%.
The above-mentioned filler powder material was sintered by heat pressing at a temperature of 150℃ for 6 minutes at a pressure such that the compression rate of the thin film for the surface layer was 10% (with a porosity of 40%).
%) Afterwards, it is rapidly cooled by cooling press processing, and the ink storage body 6, the filling powder material 5, and the thin film 4 for the surface layer are combined to complete a porous ink having a three-layer structure.

(Operations and Effects of the Invention) As the present invention is as described above, an ink storage body,
Of course, it is possible to easily obtain a porous stamp by integrating the thin film for the surface layer forming the ink supply part and the printing part, but according to the present invention, the compressibility of the powder material during the sintering process of the thin film for the surface layer is By similarly adjusting the compression ratio during the sintering process of the ink supply section, the porosity of the former is made smaller than the latter, and this small porosity increases the shape retention of the type section, preventing the section from losing its shape. In addition to preventing distortion, the large porosity of the ink supply section allows ink to be efficiently supplied to the typed area, and provides suitable elasticity for holding the typed area, thereby improving the impression of the typed area. It is possible to make the appearance even clearer, and the present invention has effects such as being able to sufficiently solve the above-mentioned problems.

[Brief explanation of drawings]

The figure shows an embodiment of the present invention.
The figure is a sectional view of the thin film for the surface layer, FIG. 2 is a sectional view of the finished product, and FIGS. 3 to 6 are sectional views sequentially showing the manufacturing process. 1...Sheet-like sintered form, 2...Female mold for letters,
3...Male mold for characters, 4...Thin film for surface layer, 5...Filled powder material, 6...Ink storage body, 7,7'...Hot plate, I...Finished product.

Claims (1)

[Claims] 1 A thermoplastic elastomer containing a hydrophilic group alone,
or a mixture of thermoplastic elastomers containing no hydrophilic groups, or a mixture of thermoplastic elastomers and hydrophilic materials, is subjected to sintering into a fine powder material obtained by chemically or physically pulverizing the mixture to give elastic properties. and a thin sheet-like sintered foam by setting the temperature, pressure, amount of powder, and time so as not to lose the microporosity at the sintering temperature, and then forming the above-mentioned sheet-like sintered foam. is inserted between a female mold for letters and a male mold for letters, and then the sintered form is subjected to a heat press process in which the sintered form is softened and deformed while maintaining a predetermined porosity, and cooling in which the sintered form is rapidly cooled in the softened and deformed state. By performing press working, a thin film for the surface layer that exhibits an uneven shape along the mold surface is formed, and after the male mold for characters is removed, a female mold for characters with the thin film for the surface layer still in place is formed. The above-mentioned powder material is filled into a mold to a predetermined appropriate amount, and an ink storage body made of a porous continuous pore sintered foam or a porous continuous pore crosslinked foam suitable for occluding ink is placed on top of the filled powder material. Then, the ink absorbing body, the filling powder material, and the thin film for the surface layer are subjected to heat press processing, and the pressure, temperature, and time are applied so that the ink absorbing body, the filling powder material, and the thin film for the surface layer maintain a predetermined porosity. A method for producing a porous stamp having continuous pores, characterized in that the ink storage body, the filling powder material, and the thin film for the surface layer are combined by setting and applying and then rapidly cooling by cooling press processing.