JPH08112981A - Offset printing blanket and manufacture thereof - Google Patents

Abstract

PURPOSE: To use a mirror for a surface of a surface rubber layer on a blanket base material and protect the surface of the surface rubber layer from flaws. CONSTITUTION: An offset printing blanket is obtained by forming a surface rubber layer on a blanket base material. In a mold 51, together with a blanket base material 57, a PET film 52 which has a surface roughness of 1μm or less on the surface side of the base material 57 and is releasable from the surface rubber layer is arranged separately from and oppositely to the base material. Thereafter, in an area between the base material 57 in the mold 51 and the film 52, the material of the surface rubber layer is injected and molded so as to form the surface rubber layer whose surface at the surface side of the film 52 is made of a mirror.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blanket for offset printing and a method for manufacturing the blanket, and more particularly to a blanket used for offset printing fine patterns such as stripes of liquid crystal color filters and mask patterns on a substrate such as glass. is there.

[0002]

2. Description of the Related Art Conventionally, blankets used for offset printing are manufactured in a long length in order to reduce the manufacturing cost. Then, in order to obtain the blanket thickness accuracy, a method of polishing the blanket surface rubber is adopted. When a liquid crystal color filter is printed using a blanket manufactured by such a method, the surface of the color filter stripe and the shape of the edge are deteriorated because the blanket surface is polished.

For example, the roughness of the surface rubber layer of a polished blanket is 3 to 5 μm even if finely polished. At this level, the stripe thickness is about 2 to 2.5 μm.
There is a hole on the surface, which causes white spots, allows light from the backlight to pass through, and causes defective color filters (see FIG. 3). In FIG. 3, reference numeral 31 indicates a blanket surface rubber layer, reference numeral 32 indicates ink, and reference numeral 33 indicates blank areas. Further, during printing, the convex portion of the polishing surface is worn away and becomes a foreign substance. When such a color filter is incorporated into a liquid crystal display and operated, the contrast and the image quality are significantly adversely affected.

[0004]

When a blanket manufactured by polishing the surface of a blanket, which is a conventional manufacturing method, is printed with a stripe for a liquid crystal color filter, the roughness of the rubber layer on the surface of the blanket has an effect. As a result, white spots and jagged edges on the printed stripes occur. When this color filter was incorporated into a liquid crystal display and operated, it had a very bad effect on contrast and image quality.

On the other hand, in order to eliminate the influence of the surface roughness of the blanket, the blanket surface is mirror-finished, for example, 1 μm.
Molding was performed using the following mold, and the same color filter printing as described above was performed. As a result, very good stripes could be printed without white spots, etc. When these printed color filters were incorporated into a liquid crystal display and operated, the contrast and image quality were very good.
However, when a blanket with a mirror surface on these blankets was transported to a user for testing, dust and scratches that had adhered during the transport of the blanket caused the white stripes and jagged stripes to appear on the printed stripes. Good printed matter was not obtained.

The present invention has been made in consideration of the above circumstances, and the blanket surface can be mirror-finished and the blanket surface can be protected from dust and scratches during transportation, and good offset printing can be achieved. It is an object to provide a blanket and a manufacturing method thereof.

[0007]

The first invention of the present application is a method for manufacturing a blanket for offset printing in which a surface rubber layer is formed on a blanket base material. After arranging a sheet having a roughness of 1 μm or less and releasable from the surface rubber layer so as to face the base material with a space therebetween, a material for the surface rubber layer in a region between the base material and the sheet in the mold. Inject, mold,
A method of manufacturing a blanket for offset printing, comprising forming a surface rubber layer having a mirror surface on the sheet surface side.

A second invention of the present application is a blanket substrate,
An offset printing blanket comprising a surface rubber layer formed on the base material and the sheet formed on the surface rubber layer.

FIG. 1 is a schematic sectional view of a blanket for offset printing according to the present invention, in which a gauge paper (for expansion prevention) 12 made of paper, resin or the like is stuck on a compression layer 11 such as a sponge rubber layer. The blanket base material, a blanket surface rubber layer 13, and a releasable sheet 14 such as a resin film (for molding and surface protection).

In the present invention, a sheet having a surface roughness of 1 μm or less and which can be released from the surface rubber layer is a film, for example, a PET film having a thickness of 0.2 mm and a thickness of 0.3.
Examples include a stainless steel film having a thickness of mm and a glass plate having a thickness of 1.0 mm. The thickness of each film or glass plate is not limited to these numerical values.

[0011]

According to the present invention, a sheet having a surface roughness of 1 μm or less on the side of the base material and a releasable mold for the surface rubber layer together with the blanket base material is opposed to the base material in the mold. After arranging, the blanket surface can be made into a mirror surface by injecting and molding the material of the surface rubber layer in the region between the base material and the sheet in the mold, and the blanket surface during transportation is dusted by the sheet used for molding. It can be protected from scratches and scratches, and good printing can be performed.

[0012]

EXAMPLES Examples of the present invention will be described below together with Comparative Examples 1 and 2. (Comparative Example 1) As shown in FIG. 2, a generally used blanket for offset printing has a structure in which a compression layer having a thickness of 0.5 mm is formed on a base layer 21 formed by laminating three cotton cloths. 22, a cotton cloth 23, and a surface rubber layer 24 having a thickness of 0.3 to 0.5 mm are formed (the total thickness is 1.9 to 2.
0 mm). A method for manufacturing such a blanket for offset printing is made long, and the surface rubber layer 24 is polished to obtain the blanket thickness accuracy. At this time, for the surface rubber layer, a silicone rubber having a good ink transfer property was used in order to transfer 100% from a blanket to a substrate such as glass. Using this blanket, a stripe having a thickness of 2 μm and a width of 80 μm for a liquid crystal color filter was printed. The blanket surface rubber roughness at this time was 3 μm.

FIG. 3 described above is an explanatory view showing the shape of stripes when printed on a blanket of an abrasive product. As for the quality of the printed stripes, the edges of the stripes were notched and there were many white spots. The ink is red,
A black matrix with three colors of green and blue and a line width of 30 μm was used. When these printed materials were incorporated into a liquid crystal color display and operated, none of them could be commercialized in terms of contrast and image quality.

(Comparative Example 2) A blanket was prepared using a split mold 41 as shown in FIG. 4 in order to make the blanket surface rubber layer a mirror surface. The reference numeral 42 in the figure
Is a silicone rubber casting port provided in the mold 41.
When a blanket is created using the mold 42 having such a configuration, it is performed as follows. (1) Apply a mixture of polybutadiene rubber and a curing agent to the gauge paper 43. (2) The gauge paper 43 is combined with the chloroprene sponge rubber layer 44 to form a blanket base material. (3) The blanket substrate is adhesively cured in an oven at 50 ° C. (4) The sponge surface of the adhesively cured blanket substrate is ground to a thickness of 1.0 mm. (5) Apply the product name: Primer A of Shin-Etsu Chemical Co., Ltd. as an adhesive on the gauge paper surface of the blanket base material. (6) The blanket base material is mounted in the mold 41 as shown in FIG. 4 (the surface roughness of the inner surface 41 ′ of the mold at this time is a mirror surface of 1 μm or less). (7) Cast silicone rubber from the silicone rubber casting port 42. (8) Heat cure at 110 ° C. for 30 minutes. (9) After demolding, cut the product to size.

When printing was carried out in-house using the blanket thus produced, very good stripes could be printed. The stripe shape at this time is 2 μm in thickness.
m and the width was 80 μm. Next, when the blanket thus produced was conveyed to the user and stripes were printed, white spots on the stripes and jagged phenomenon occurred. As a result of investigating the cause, it was found to be the effect of dust adhesion and scratches during transportation. In addition, in the case of Comparative Example 2, in order to protect the surface of the surface rubber layer from dust, scratches, and the like during transportation, it is necessary to attach a protective film to the surface rubber layer of the blanket made by the mold 41, which is unnecessary. It takes a process. In addition, dust may adhere during the application of the protective film.

(Embodiment 1) In order to make the blanket surface rubber layer a mirror surface, the mold 51 has a thickness of 0.2 mm and a surface roughness of 0.3.
A PET film 52 of ˜0.4 μm was used (see FIG. 5). Reference numeral 53 in the figure is a silicone rubber casting port provided in the mold 51. Next, a blanket manufacturing method will be described. (1) A mold release agent 54 is applied to the mirror surface PET film 52. (2) The film 52 coated with the release agent 54 is set in the mold 51 as shown in FIG. (3) Apply the adhesive to the gauge paper 55. (4) The chloroprene sponge rubber layer 56 is attached to the adhesive application surface side of the gauge paper 55 to form a blanket base material 57. (5) Bond and cure in an oven at 50 ° C. (6) The surface of the chloroprene sponge rubber layer 56 of the blanket base material 57 is ground to 1.0 mm. (7) Apply primer A as an adhesive on the gauge paper side. (8) The blanket substrate 57 coated with primer A
Is set in the mold 51 as shown in FIG. (9) Silicone rubber is cast from the silicone rubber casting port 53 of the die 51. (10) Heat cure at 110 ° C. for 30 minutes. (11) After demolding, cut into dimensions and commercialize.

The PET film 52 for pattern making of this blanket is conveyed to the user as it is without releasing the mold, and the PET film 52 for pattern making is peeled off from the blanket immediately before printing to expose the blanket printing surface. A stripe having a thickness of 2 μm and a width of 80 μm for a filter was printed. Good printing was possible without stripes and white spots. When this color filter was incorporated into a liquid crystal color display and operated, very good contrast and image quality could be obtained. Further, the PET film 52 for mirror surface shaping made the surface of the blanket mirror surface. Further, by carrying the PET film 52 with the blanket surface attached, it was possible to prevent dust and scratches during carrying. Furthermore, since it is not necessary to mirror-finish the die 51 unlike the die of FIG. 4, the die cost can be reduced and the die need not be sensitive to scratches.

[0018]

As described in detail above, according to the present invention, the surface of the blanket base material and the surface of the base material have a surface roughness of 1 μm in the mold.
After arranging a sheet of m or less and capable of releasing from the surface rubber layer so as to face the base material with a space therebetween, the material of the surface rubber layer is injected into a region between the base material and the sheet in the mold. By molding, the blanket surface can be easily made into a mirror surface without using a mirror-finished die, and the blanket surface can be protected from dust, scratches, etc. during transportation, and good printing can be achieved at low cost. A blanket for offset printing and a method for manufacturing the same can be provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a blanket for offset printing according to the present invention.

FIG. 2 is a schematic sectional view of a conventional blanket.

FIG. 3 is an explanatory diagram of a “white spot” state that occurs when ink is transferred from a blanket to a glass plate.

FIG. 4 is an explanatory view of a mold used for manufacturing a blanket for offset printing according to a comparative example.

FIG. 5 is an explanatory diagram of a mold used for manufacturing an offset printing blanket according to an embodiment of the present invention.

[Explanation of symbols]

11 ... Compression layer, 12 ... Resin film, 13 ...
Surface rubber layer, 14 ... Resin film, 51 ... Mold,
52 ... PET film, 53 ... Silicone rubber casting port, 54 ... Release agent, 55 ... Gauge paper, 56 ... Chloroprene sponge rubber layer, 57 ... Blanket base material.

Claims (2)

[Claims] 1. A method for producing an offset printing blanket in which a surface rubber layer is formed on a blanket base material, comprising: a blanket base material having a surface roughness of 1 μm or less on the base material surface side with respect to the surface rubber layer in a mold. After arranging the releasable sheet so as to face the base material apart from the base material, the material of the surface rubber layer is injected and molded in the region between the base material and the sheet in the mold, and the sheet surface side is a mirror surface. A method for producing a blanket for offset printing, which comprises forming a surface rubber layer that is 2. A blanket base material, a surface rubber layer formed on the base material, and the sheet according to claim 1 formed on the surface rubber layer, for offset printing. blanket.