JPH0380634B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applied to the field of rubber stamps as shown in FIG. The present invention relates to a method of manufacturing a rubber printed body 2 in which a portion 5 is formed to protrude.

More specifically, in order to improve the adhesion of the ink to the printed surface and ensure good transferability of the ink to the paper surface, an extremely thin porous rubber coating layer 4 is applied to the surface of the non-porous rubber base layer 3. This relates to a method of manufacturing a rubber printed body 2 having a cross-sectional structure in which the following are integrally laminated.

[Conventional technology]

As a prior art regarding this type of rubber printed body 2, there is Japanese Utility Model Application Publication No. 55-63763. This is the fourth
To explain with a diagram, the rubber printed body 2 attached to the lower end of the rootstock 1 is formed by integrally laminating a porous rubber coating layer 4 on the surface of a rubber base layer 3 with almost no air bubbles. When the rubber base layer 3 is adhered to the rubber base layer 3 and the rubber base layer 3 is put into use, continuous imprinting can be performed using the ink contained in the porous rubber coating layer 4.

In this process, easily soluble substances such as common salt are uniformly mixed into unvulcanized rubber materials, vulcanized and molded in a mold, and then the intermediate molded product is placed in a liquid to extract the easily soluble substances. As a result, a porous rubber printed body 2 is obtained.

[Problem that the invention seeks to solve]

However, in the conventional example shown in the above-mentioned Japanese Utility Model Publication No. 55-63763, the aim is to enable clear and continuous printing of 10 times or more. For this purpose, the total thickness of the rubber printed body 2 is set to approximately 3.0 mm, and the porous rubber coating layer 4 is set to a thickness of approximately 1.0 mm. In this case, the porous rubber coating layer 4 on the surface becomes too thick, and the entire printed portion 5 formed to protrude has a cross-sectional structure composed of the porous rubber coating layer 4.

In such a conventional example, firstly, the printed part 5, which was originally finished with a fine uneven relief, has become porous and the material is fragile, so the printed part 5 is easily broken off during use. Cheap.

Secondly, the printing part 5 is compressed and deformed excessively during stamping, which inevitably causes the impression to lose its shape and the ink to become sticky, and the present invention does not have a stopper means to prevent excessive compression. It is difficult to put rubber stamps into practical use.

Thirdly, since the porous rubber coating layer 4 is thick and the rubber base layer 3 is basically formed to be porous, it takes time to extract easily soluble substances from the intermediate molded product. , this extraction work is time-consuming, and the formation cycle, ie, productivity is poor.

Fourth, when an easily soluble substance is uniformly mixed into an unvulcanized rubber substance and then vulcanized and molded, and the intermediate molded product is placed in a liquid to extract the easily soluble substance, the entire rubber printed body 2 becomes easily soluble. It should have the same porosity commensurate with the amount of mixed materials. Setting the porosity of the rubber coating layer 4 to a large value and forming the porosity of the rubber base layer 3 to a uniform value as in the conventional example requires special treatment and the manufacturing process is complicated. I can imagine it would be troublesome.

Fifth, in the rubber stamp to which the present invention is applied, it depends on the surface relief of the rubber print body 2, but its size (contact area and size to the paper surface), the hardness of the rubber base layer 3, and the rubber print body 2 The relationship between the total thickness of the rubber coating layer 4 and the thickness of the rubber coating layer 4 relative to the rubber base layer 3 becomes a problem. For example, if the hardness of the rubber base layer 3 is high and the thickness of the rubber coating layer 4 is small, part of the stamp impression will tend to fade when the area of the rubber print body 2 is large; This is because if the hardness is too low, the stamp impression becomes sticky and tends to lose its shape when the area of the rubber printed body 2 is small. However, changing the hardness of the rubber base layer 3 and the thickness of the rubber coating layer 4 each time according to the size of the rubber print body 2 requires preparing a wide variety of rubber print bodies 2, which increases production costs. It's not a good idea. Conventional examples lack awareness regarding this point. Incidentally, although there is also a description in the conventional example that the rubber hardness is set at 50 to 60°,
It is unclear whether this refers to the hardness of the entire rubber printed body 2, which has a two-layer structure, or the hardness of the porous rubber coating layer 4 alone, and it is difficult to find any significance in this.

[Purpose of the invention]

An object of the present invention is to obtain a rubber printed body on which ink can easily be applied and which can ensure good transferability of the ink to the paper surface.

An object of the present invention is to obtain a rubber printed body with excellent durability, in which printed portions formed protruding from the surface are hard to come off.

SUMMARY OF THE INVENTION An object of the present invention is to provide a manufacturing method that allows a rubber printed body to be molded easily and with high precision and contributes to improving productivity.

The most important object of the present invention is to be able to adapt to a single specification of the cross-sectional shape of a rubber printed body, regardless of its size. That is, the objective is to make it possible to use a single specification for rubber printed bodies ranging in area from large ones of about 10 cm x 3 cm to small ones of 7 mm square.

[Means for solving problems]

As shown in FIG. 2, the present invention first provides an unvulcanized second rubber material 4a containing easily soluble substances such as salts and sugars on the surface of an unvulcanized sheet-like first rubber material 3a.
and the step of applying the first and second rubber substances 3.
A and 4a are placed in a mold and vulcanized, and a printed part 5 is formed to protrude on the surface.The intermediate molded product after molding is placed in a liquid and an easily soluble substance is extracted from the second rubber substance 4a. It goes through the process of

Thus, as shown in FIG.
Rubber hardness at a is 55 to 65°, more preferably 62 to 64°
A non-porous rubber base layer 3 having an average thickness of 0.1 to 0.35 mm, more preferably 0.25 to 0.35 mm is formed on the surface of the rubber base layer 3 with a second rubber substance 4a. Porous rubber coating layer 4
are integrally laminated to produce a rubber printed body 2 in which the overall height H of the protruding portion of the printed portion 5 is set to 2.0 to 3.0 mm.

Here, set the rubber hardness of the rubber base layer 3 to 55 to 65 degrees.
The reason for this setting is that if the rubber coating layer 3 is made softer than 55 degrees, even if the thickness of the rubber coating layer 3 is made as small as possible, the print will lose its shape when the area of the rubber print body 2 is small. On the other hand, if the rubber print body 2 becomes hard beyond 65°, its adhesion to the uneven paper surface becomes poor when the area of the rubber print body 2 is large, and the stamp impression tends to be partially blurred.

In addition, the average thickness of the rubber coating layer 4 is 0.1 to 0.35 mm.
The reason for this setting is that if it exceeds 0.35 mm, the compressive deformability of the rubber printing body 2 will become too high, and regardless of the size of the rubber printing body 2 (this is especially noticeable when it is small), it will hold too much ink and the stamp will not be printed. This results in loss of shape and stickiness due to excess ink. On the other hand, the thickness is 0.1mm
If it is lower than this, there is a risk that a part of the rubber base layer 3 will be exposed to the outside, and the original function of the rubber coating layer 4 to adsorb ink will not be fully demonstrated, especially if the area of the rubber printed body 2 is This is because, if the amount of paper is large, even a slight uneven contact with the paper surface will result in poor transfer.

〔Effect of the invention〕

According to the present invention as described above, the rubber printed body 2 affixed to the lower end surface of the rootstock 1 is mainly composed of a non-porous rubber base layer 3, and this rubber base layer 3 has an angle of 55° to 60°. Since the rubber has a hardness of 100°C, it has a suitable overall elasticity and is comfortable to press. In addition, it has good adhesion to the paper surface, that is, it has good adhesion (hitting), and it is possible to prevent the surface of the rubber printed body 2 from being unevenly hit, and is particularly effective for large-sized rubber stamps.

Then, a porous rubber coating layer 4 having an average thickness of 0.1 to 0.35 mm was integrally laminated on the surface of the rubber base layer 3. Therefore, when the rubber printed body 2 is brought into pressure contact with the ink stamp stand, the ink is well adsorbed and captured in the fine pores of the rubber coating layer 4, and the ink adhesion to the surface of the rubber printed body 2 is improved. When the coating layer 4 is pressed against the paper surface, good transferability of ink to the paper surface can also be ensured.

In particular, in the present invention, the total height H of the printed portion 5 of the rubber printed body 2 is set to 2.0 to 3.0 mm, and the average thickness of the rubber coating layer 4 is set to be extremely thin, 0.1 to 0.35 mm, so that the rubber coating layer 4 can be compressed by itself. The amount of deformation was suppressed, and the hardness of the rubber base layer 3 was set at 55 to 65 degrees. Therefore, first of all, molding defects such as when a part of the rubber base layer 3 breaks through the rubber coating layer 4 and is exposed on the printing surface can be effectively prevented. Second, even when the area of the rubber printed body 2 is large, the appropriate elasticity and thickness of the rubber base layer 3 ensure good adhesion to the paper surface. Thirdly, even when the area of the rubber printed body 2 is small, the upper limit of the thickness of the rubber coating layer 4 is 0.35.
mm, it is possible to prevent excessive compression deformation without a stopper means. Fourthly,
The total height H of the printing part 5 of the rubber printing body 2 is 2.0~
3.0mm, whereas the average thickness of the rubber coating layer 4 is
Since the thickness is 0.1 to 0.35 mm, the entire protruding printed portion 5 is not porous, and in this respect too, excessive compressive deformation of the printed portion 5 is suppressed to ensure a sharp impression. Although the rubber printed body 2 has a single specification, it has the greatest advantage in that it can be used with rubber stamps of different sizes and can always reliably prevent the impression from deforming and the ink from becoming sticky.

Moreover, since the cross-sectional structure of the rubber printed body 2 can be made into a single specification, there is no variation in the thickness of the rubber base layer 3 and especially the rubber coating layer 4, and the same rubber substances 3a and 4a can be used to constitute these layers. Therefore, it is suitable for mass producing high quality rubber printed bodies 2 at low cost.

Furthermore, in order to make the rubber coating layer 4 porous, the process of placing the intermediate molded product in a liquid and extracting easily soluble substances from the rubber substance 4a takes the most time during its production, but in the present invention, the rubber coating layer 4 Since the layer 4 is set to be extremely thin with an average finished thickness of 0.1 to 0.35 mm, and it is only necessary to extract easily soluble substances from the rubber substance 4a on the surface, this extraction process can be carried out in a short time. In this respect as well, it is possible to increase the molding cycle and improve productivity.

In addition, since the rubber printed body 2 is attached to the lower end of the rootstock 1 via the non-porous rubber base layer 3, the ink does not penetrate into the adhesive through the rubber base layer 3, and therefore the rubber stamp on the rootstock 1 The adhesion of the font 2 can also be maintained well over a long period of time.

〔Example〕

In FIG. 2, an unvulcanized second rubber material, in which easily soluble substances such as salts and sugars are mixed on the surface of an unvulcanized first sheet-like rubber material 3a having a thickness of 1.5 to 2.3 mm, is shown.
Apply the rubber substance 4a thinly with a brush or spatula. Next, the first and second rubber substances 3a and 4a are put into a mold and heated and pressurized.
After vulcanizing the rubber material 4a and molding the printed portion 5 into a protruding shape on the surface, the intermediate molded product is placed in a liquid to extract the easily soluble substance from the second rubber material 4a, and finally the desired width is formed. The rubber printed body 2 was made by cutting.

In such a case, as shown in Fig. 1, a non-porous rubber base layer 3 is formed with a first rubber substance 3a, and a porous rubber coating layer 4 is integrally formed with a second rubber substance 4a on the surface of the rubber base layer 3. Laminated layers are formed.

When the coating thickness of the second rubber substance 4a was 0.5 mm, the average thickness of the rubber coating layer 4 after molding was about 0.3 mm. The porosity of the rubber coating layer 4 is 60 to 90%,
Preferably it was set at 68-70%. Although it depends on the size of the rubber printed body 2, the total height H of the protruding printed portion 5 was set to a value of 2.0 to 3.0 mm.

The rubber substances 3a, 4a constituting the rubber base layer 3 and the rubber coating layer 4 are mutually compatible and preferably consist of the same substance, generally NBR (acnylonitrile butadiene rubber). Natural rubber (NR), polyvinyl chloride, vinyl chloride/vinylidene chloride copolymer, etc. can also be used.

The rubber printed body 2 thus obtained was directly adhered to the lower end surface of the rootstock 1 via the rubber base layer 3 to obtain the rubber stamp shown in FIG. 3. The rubber printed body 2 may be attached to the rootstock 1 via an elastic mat member or the like. The rootstock 1 is not limited to being made of wood, but may also be made of plastic material, especially for small rubber stamps.

Incidentally, according to the prototype produced by the present inventor, the rubber hardness of the rubber base layer 3 is 63°, and the rubber coating layer 4 has a hardness of 63°.
When using the rubber print body 2 with a thickness of 0.3 mm, the same specifications could be applied to large rubber stamp formats, that is, large ones measuring 10 cm x 3 cm to small ones measuring 7 mm square.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of the main part, FIG. 1 is an external perspective view of a rubber stamp to which the invention is directed.
FIG. 4 is a longitudinal cross-sectional view of the main parts of a conventional rubber printed body. DESCRIPTION OF SYMBOLS 1... Rootstock, 2... Rubber printed body, 3... Non-porous rubber base layer, 3a... Rubber substance constituting the rubber base layer, 4... Porous rubber coating layer, 4a...
Rubber substance constituting the rubber coating layer, 5...Printed portion.

Claims (1)

[Scope of Claims] 1. In a method for manufacturing a rubber printed body 2 affixed to the lower end of a rootstock 1, on the surface of an unvulcanized sheet-like first rubber substance 3a,
Unvulcanized secondary materials containing easily soluble substances such as salts and sugars
A step of applying a rubber substance 4a, a step of putting the first and second rubber substances 3a and 4a into a mold and vulcanizing them, and a step of protruding a printed part 5 on the surface, and forming an intermediate molded product after molding. A step of extracting the easily soluble substance from the second rubber substance 4a by placing it in a liquid, and forming a non-porous rubber base layer 3 having a rubber hardness of 55 to 65° with the first rubber substance 3a. , a second rubber substance 4 is formed on the surface of the rubber base layer 3.
A porous rubber coating layer 4 having an average thickness of 0.1 to 0.35 mm is integrally laminated, and the printed portion 5 is
A method for manufacturing a rubber printed body in which the total height H at the protruding portion is set to 2.0 to 3.0 mm.