JP2835657B2 - Manufacturing method of printing blanket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a printing blanket, and more particularly to a method for producing a printing blanket which does not require talc for preventing adhesion between a surface rubber and vulcanized paper.

[0002]

2. Description of the Related Art Compressible printing blankets provided with a compressible layer and non-compressible printing blankets not provided with a compressible layer are used as printing blankets used in high-speed offset printing presses. In any of the blanket manufacturing methods, talc is used in vulcanizing to prevent adhesion between the surface rubber and the vulcanized paper. In other words, after applying the surface rubber, when vulcanizing, the vulcanized paper is wound around a roll while sandwiching the vulcanized paper, but if the vulcanized paper is directly laminated on the surface rubber, the vulcanized paper will not peel off after vulcanization, In order to prevent sticking, talc is powdered on the surface rubber, and the vulcanized paper is wound while being laminated.

Further, a conventional method for manufacturing a compressible printing blanket will be described with reference to FIG.
Apply rubber paste to rayon cloth, polyester cloth, etc.
The support 2 is formed by laminating three to three layers, and the compressible layer 4 is provided on the support 2. Further, an oil-resistant surface rubber layer 8 serving as a printing surface is applied on the compressible layer 4 via a support 6 made of cotton cloth. Then, talc 10 is applied to the surface rubber layer 8.
Is subjected to dustproofing treatment. Talc 1 on surface rubber 8
0, the vulcanized paper 12 such as art paper
Is wound up in a roll while sandwiching it.

[0004] The vulcanized paper 12 is then vulcanized in a rolled state, and is rewound to remove the vulcanized paper 12 whose vulcanization is completed. At this time, since talc is blown between the surface rubber 8 and the vulcanized paper 12 to prevent adhesion, the vulcanized paper 12 can be peeled off smoothly. When the vulcanized paper 12 is peeled off, the surface is finally polished by a polishing machine such as a sandpaper grinder or the like, and the surface is formed into a fine uneven surface having a predetermined roughness. This surface roughness is usually formed with a 10-point average roughness of 2 μm to 15 μm using a stylus-type roughness meter.

[0005]

As described above, the production method using talc for preventing adhesion between the surface rubber 8 and the vulcanized paper 12 has the following problems. From the viewpoint of blanket quality, there is a problem that printing quality lacks stability. That is, some talc not only adheres to the surface but is completely buried in the surface rubber 8, so that it is difficult to completely remove the talc even by polishing at the time of forming the surface. Therefore, talc often remains with being attached to the printing surface, and the talc has hindered the transfer of the ink. Therefore, it was necessary to print a considerable number of sheets before the talc was completely removed and the print quality was stabilized. Further, the talc causes clogging of the polishing paper, and a predetermined surface roughness cannot be obtained.

[0006] From the viewpoint of the working environment, dust is generated during dusting and removal of talc, thereby deteriorating environmental hygiene. In addition, since the production equipment is heavily soiled, environmental hygiene is protected and product quality is maintained. In order to do this, cleaning must be done frequently. Therefore, there is a problem that the working efficiency is reduced. Further, there is a problem that the cost is increased from the viewpoint of cost. That is, in order to reduce the adhesion of talc by polishing, a large amount of polishing must be taken. The larger the polishing allowance, the longer the polishing time and the higher the cost.

The present invention has been made in view of such a situation, and has made it possible to prevent sticking at the time of vulcanization without using talc, so that stable printing quality can be obtained and work efficiency is improved. An object of the present invention is to provide a method of manufacturing a printing blanket that can reduce the cost of a product while maintaining a favorable environment.

[0008]

The present invention has the following configuration to achieve the above object. That is, at least one support and a surface rubber layer serving as a printing surface are provided, a coating layer of a photocrosslinkable composition is provided on the surface rubber layer, the coating layer is crosslinked, and then the surface rubber layer is vulcanized. After that, the coating layer is removed by polishing to make the upper surface of the surface rubber layer a fine uneven surface. The vulcanization of the surface rubber layer is preferably performed by winding it up on a roll, and when winding up the roll, a vulcanized paper may be sandwiched.

[0009]

The coating layer of the photocrosslinkable composition on the surface rubber layer is crosslinked to form a cured thin film layer on the surface rubber layer. work. Therefore, it is not necessary to use talc as an anti-adhesion material.

[0010]

Next, the present invention will be described in detail based on embodiments. FIG. 1 is an explanatory view showing the steps of the manufacturing method according to the present invention. First, a blanket having a known structure is manufactured.
For example, after forming a support 20 by laminating rubber paste on a cotton cloth and laminating it in two layers, forming a compressible layer 21 thereon,
Further, a support 23 made of cotton cloth is provided on the compressible layer 21.
, An oil-resistant surface rubber layer 25 serving as a printing surface is applied and laminated. The supports 20 and 23 may be made of known woven fabrics such as rayon fabrics and polyester fabrics in addition to cotton fabrics. The surface rubber layer may be made of, for example, oil-resistant chloroprene rubber, nitrile rubber, acrylic rubber, or the like. It is used by adding one or more kinds of vulcanizing agent such as sulfur, vulcanization accelerator, anti-aging agent, etc. to rubber, and is applied and laminated to a thickness of 0.2 to 0.8 mm by a spreader, knife coater, roll coater, etc. Is done.

A photocrosslinkable rubber composition obtained by adding a photosensitizer is coated on the surface rubber layer 25.
The coating layer 27 may have a thickness that forms a thin film capable of preventing sticking during winding, and may be, for example, a coating layer having a thickness of 1 to 20 μm. After the coating layer 27 of the photocrosslinkable rubber composition is provided on the surface rubber layer 25 in this manner, the coating layer 27 is irradiated with ultraviolet rays to be crosslinked to form a cured thin film layer.

After the coating layer 27 is cured, the surface rubber layer 25 is vulcanized. Vulcanization is carried out by winding the film on a roll in the same manner as in the prior art. When the film is wound on a roll, vulcanized paper such as art paper is placed on the coating layer 27 so that the coating layer 27 can be wound in a smooth state. It is preferable to sandwich 29. That is, when the vulcanized paper 29 is not used, the unevenness of the support 20 is formed on the surface rubber layer 25 as it is because the coating layer 27 is a cured thin film layer when wound on a roll. This is because if vulcanization is performed in this state, the polishing allowance for the surface rubber layer 25 increases by the amount of the irregularities. However, the vulcanized paper 29 can be omitted by adjusting the thickness of the coating layer 27 and the like.

When the vulcanizing step is completed, the process shifts to a balancing step for removing the vulcanized paper 29. Conversely, the vulcanized paper 29 may be removed only by peeling off the vulcanized paper 29 while winding it up on a roll. The cured coating layer 27 does not cause the support 20 to stick, so that the vulcanized paper 29 can be easily released.
When the use of the vulcanized paper 29 is omitted during vulcanization,
Naturally, this balancing step is omitted, and the process can proceed to the next polishing step.

In the polishing step, the coating layer 27 is removed, and the surface rubber layer 25 is formed with a fine uneven surface having a predetermined roughness. The removal of the coating layer 27 is performed by a polishing machine such as a sandpaper grinder.
The surface of No. 5 is polished, and the surface is formed into a fine uneven surface having a predetermined roughness. As for this surface roughness, a 10-point average roughness is usually 2 μm to 15 μm, preferably 5 μm by a stylus type roughness meter.
７7 μm.

Since the present invention is characterized in that tackiness can be prevented without using talc at the time of vulcanization, the structure of the blanket is not limited. Therefore, it does not matter whether the blanket is a compressible printing blanket or a non-compressible printing blanket. Of course, the support is replaced with a woven fabric, and a strong and high tensile strength paper sheet, such as a rubber-impregnated paper, is used. , Kraft paper or chimpan paper, or the like, and a laminate of a high tensile strength plastic sheet may be used.

[0016]

According to the present invention, the following effects can be obtained. During vulcanization by forming a coating layer with a photocrosslinkable composition, of course, the use of talc,
Since the use of vulcanized paper can be omitted, the manufacturing process can be simplified. In addition, printing defects caused by the use of talc are eliminated, and stable printing quality is obtained. Further, the removal of the coating layer can be easily performed by polishing the surface with a polishing machine, and the cost of the product can be reduced while maintaining a good working efficiency and a good working environment.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a manufacturing process of the present invention.

FIG. 2 is a schematic explanatory view showing a conventional blanket manufacturing process.

[Explanation of symbols]

 Reference Signs List 20 support 21 compressible layer 23 support 25 surface rubber layer 27 photocrosslinkable composition coating layer 29 vulcanized paper

Claims (1)

(57) [Claims] At least one support and a surface rubber layer serving as a printing surface are provided, and a coating layer of a photo-crosslinkable composition is provided on the surface rubber layer to crosslink the coating layer. After vulcanizing the coating, the coating layer is removed by polishing , and the upper surface of the surface rubber layer is formed into a fine uneven surface.