JP2536762B2 - Printing blanket and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a printing blanket and a method for manufacturing the same, and more particularly, to a printing blanket having a good paper discharge property and a method for manufacturing the same.

(Technical background of the invention) As for a printing machine, for example, when an offset printing machine is taken as an example, a plate copper 1 on which a plate to be a document is wound and a blanket 5 which rotates in conjunction with the plate copper 1 are wound. Blanket copper 2
The blanket copper 2 and the press copper 4 for sandwiching the printing paper 3 under pressure are basically constructed.
Then, ink is adhered to the plate wound around the plate copper 1, the image formed by the ink is once transferred to the blanket 5 of the blanket copper 2, and the transferred image is printed on the contacting printing paper 3. It is a thing.

As shown in FIG. 2, the blanket 5 used in such a printing machine generally has a compression layer 52 made of an elastic material formed on a machine cloth 51 as required, and further has a surface layer 53 on the compression layer 52. The printing paper 3 contacts the surface layer 53 with the surface layer 53.

One problem in using such a printing blanket 5 is that the printing blanket 5 is attached to the printing paper 3.
It can be mentioned that the printing blanket 5 and the printing paper 3 are less likely to be peeled off after being printed by. It is considered that this is mainly caused by a vacuum state occurring between the surface layer 53 of the printing blanket 5 and the printing paper 3, and the printing paper 3 being adsorbed on the surface of the blanket 5. Therefore, as shown in FIG. 2, the surface of the surface layer 53 of the printing blanket 5 is polished to form a rough surface 54, and the rough surface 54 allows air to easily enter between the blanket 5 and the printing paper 3. And has a structure that allows good peeling.

However, in the printing blanket having the structure in which the rough surface 54 is provided by the above-described polishing, it has not been possible to maintain a good paper discharge property. That is, in order to secure a good paper discharge property, it is necessary to perform polishing for a long time and increase the number of the rough surfaces 54. However, if the number of the rough surfaces is increased in this way, the halftone dot reproducibility is deteriorated and the printing is good. This will result in being unable to do so. For this reason,
The current situation is to ensure good halftone dot reproducibility by sacrificing the paper discharge property.

(Summary of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to provide a printing blanket having a better paper discharge property and halftone dot reproducibility than a conventional one, and a manufacturing method thereof. And

Therefore, the printing blanket according to the present invention is a printing blanket having a surface layer that comes into contact with an object to be printed on a base fabric, and the surface of the surface layer is polished to a rough surface, and through an adhesive layer, Cylindrical protrusions are provided at a density of 20 to 70%, the top surface dimension of the protrusions is 5 to 50 μm, and the height is 2.5 to 25 μm.

Further, according to the method for producing a printing blanket according to the present invention, an oil-resistant or solvent-resistant polymer is laminated on a base fabric, vulcanized to form a surface layer, and then the surface layer is polished and bonded. The agent is applied, then the photosensitive resin is laminated at a rate of 2.5 to 35 g / m ² , and the density is 20 to 70% in a dot shape of 5 to 50 μm.
And a non-exposed portion is removed by etching.

According to the printing blanket of the present invention, the surface of the surface layer is polished to form a rough surface, and cylindrical projections are provided on the rough surface at a density of 20 to 70% via an adhesive layer. In addition, the size of the protrusion is 5 to 50 μm, and the height is 2.5 to 2
It has been found that a thickness of 5 μm can provide a printing blanket having a good paper discharge property. That is, as a result of earnest studies of the printing blanket surface layer having a rough surface formed by such polishing, the present inventor has found that the height of peaks and valleys of the rough surface of the surface layer by the conventional polishing is 1 to 10 μm, The pitch between (valley-valley) is
It was found that the thickness was in the range of 50 to 100 μm, and based on this result, the surface layer structure having a good paper discharge property and a good dot reproducibility was determined. Then, through an adhesive on the rough surface by polishing as described above, further providing a cylindrical protrusion, by controlling the density and size of the protrusion,
The present invention has been completed by discovering that the printing blanket has excellent paper discharge properties while maintaining good halftone dot reproducibility.

Further, according to the method for producing a printing blanket according to the present invention, an oil-resistant or solvent-resistant polymer is laminated on a base fabric, vulcanized to form a surface layer, and then the surface layer is polished and bonded. The agent is applied, and the photosensitive resin is applied at a rate of 2.5 to 35 g / m ² , and the density of the dots is 5 to 50 μm.
By exposing at a rate of 20 to 70% and removing the unexposed portion by etching, it is possible to form protrusions with good dimensional controllability, uniformity, and uniform density on the rough surface layer,
Therefore, there is an advantage that it is possible to manufacture a printing blanket having good paper discharge properties and halftone dot reproducibility.

(Detailed Description of the Invention) In the printing blanket according to the present invention, as shown in FIG. 3, a compression layer 52 made of an elastic material is laminated on a base fabric 51, and a surface layer 53 is further formed on the compression layer 52. It has a formed structure. The surface of this surface layer 53 is roughened by polishing.
Is formed on the rough surface 54, the rough surface 54
An adhesive 55 is applied to the adhesive layer 55, and a plurality of protrusions 56 are further formed on the adhesive layer 55, so that good paper discharge performance can be ensured.

The rough surface 54 is for not only ensuring the paper ejection property but also the adhesiveness of the protrusions 56. Usually, as in the case of the rough surface 54 of this type, the height of the peaks and valleys is 1 to 10 μm. , The pitch between peaks (valleys) is preferably in the range of 50 to 100 μm. If it deviates from this range, the halftone dot reproducibility and the paper ejection property may be impaired, and the adhesiveness of the protrusions 56 may be impaired.

The adhesive 55 applied on the rough surface 54 is provided in order to fix the projection 56 with good adhesive strength. Therefore, basically any material can be used as long as it can satisfactorily bond the above-mentioned protrusion 56. For example, two-component urethane resin,
One or more types of isocyanate-containing synthetic rubber paste and the like can be used. The thickness of the adhesive layer 55 is preferably 2 to 20 μm. If it is less than 2 μm, good adhesive strength may not be secured, while if it exceeds 20 μm, the adhesive strength is reduced and the thickness accuracy is reduced.

The shape of the protrusion 56 formed on the adhesive layer 55 is not basically limited, and for example, as shown in the front view of FIG. 4, the top surface shape may be circular, Also, various shapes such as an ellipse and a square can be used. Further, the arrangement of the protrusions 56 is not basically limited in the present invention, and for example, the protrusions 56 may be arranged alternately as shown in FIG.

Such protrusions 56 are formed on the surface layer 53 in the present invention.
It is provided with a density of 20 to 70%. If this density is less than 20%, the projections 56 may be too small to ensure good paper discharge performance, while if it exceeds 70%, the halftone dot reproducibility may be impaired.

The size of such a protrusion 56 is 5 to 50 μm. If the protrusions 56 are too small, it may be difficult for air to enter between the printing paper 3 and the printing blanket 5, and the paper ejection performance may not be good. This is because it may cause damage. here,
The dimension of the protrusion 56 is indicated by the length of the longest portion of the top surface of the protrusion 56. That is, when the shape of the top surface is circular, it is the diameter of the circle, when it is square, the diagonal line,
If the shape is elliptical, it means the length of the major axis.

The height of the protrusion 56 is 2.5 to 25 μm. If the height of the protrusions 56 is less than 2.5 μm, the paper ejection property may be deteriorated, while if it exceeds 25 μm, the halftone dot reproducibility may be impaired.

Next, a method for manufacturing the printing blanket of the present invention will be described.

According to the method for producing a printing blanket of the present invention, first, the surface layer is formed after forming the compression layer on the base fabric or without forming the layer.

When manufacturing this surface layer, first, an oil-resistant or solvent-resistant polymer, which is a base material for forming the surface layer, is provided by coating or the like on the base cloth without the compression layer.

In the present invention, the base cloth or the compression layer is not particularly limited, and the base cloth or compression layer conventionally used in this type of printing blanket can be effectively used. For example, the base fabric can be a base fabric made of cotton, strong human silk, or a reinforced fiber (Kevlar fiber or the like) having little stretchability.

The compression layer has a compressive stress of 2.0 to 8.0 kg / c.
Elastic bodies in the m ^{2 range} (stress at 1 mm / min compression rate, 0.15 mm compression) can be used. Various types of such elastic bodies are known.

According to the present invention, a surface layer is formed on such a base fabric or a compression layer, and the oil-resistant polymer or solvent-resistant polymer which is the base material of this surface layer is basically used in the present invention. It is not limited. The polymers conventionally used for forming this type of surface layer can be effectively used. For example, one or more of acrylonitrile-butadiene rubber (NBR), polyvinyl chloride, chloroprene rubber, fluorine rubber, acrylic rubber, polysulfide rubber, polyurethane, hydrin rubber and the like can be used. One or more of vulcanizing agents such as sulfur, vulcanization accelerators, antioxidants, processing aids such as stearic acid, etc., added to such polymers conventionally in oil-resistant or solvent-resistant polymers. Ingredients can be added.

Such oil-resistant polymers or solvent-resistant polymers are usually used in a semi-fluid state, and examples of the solvent include at least one kind of ethane dichloride and toluene.

After the unvulcanized surface layer is formed from such an oil-resistant polymer or solvent-resistant polymer, it is vulcanized to form the surface layer 53.

After the surface layer 53 is formed in this way (Fig. 5a), it is polished to form a rough surface 54 (Fig. 5b).

This polishing is not basically limited in the present invention, and the polishing method conventionally used in this type of manufacturing method can be effectively used.

After forming the rough surface 54 in this way, an adhesive 55 is applied as shown in FIG.

Such an adhesive 55 is as described above,
This coating amount is preferably ² to 25 g / m ² . If it is less than 2 g / m ² , the adhesive strength may not be sufficiently secured, while if it exceeds 25 g / m ² , both the adhesive strength and the thickness accuracy may be reduced.

After applying such an adhesive 55, a photosensitive resin 57 is laminated.

The photosensitive resin is basically not limited in the present invention, but may be formed on the adhesive 55, contact with a printing ink, contact with a non-printed material, etc. Considering this, it is preferable that it has elasticity, good compression set, oil resistance, and good adhesive strength with the adhesive 55.
As such a photosensitive resin, urethane type or polyester type can be used. Specific examples of such a photosensitive resin include, for example, APR (Asahi Kasei Co., Ltd.), Devista (Tokyo Ohka Kogyo Co., Ltd.), UD-022M (Yokohama Rubber Co., Ltd.), APL (Toray Co., Ltd.), NAPP (Japan). Paint Co., Ltd.), etc.

This photosensitive resin is applied to the surface layer at a rate of 2.5 to 35 g / m ² . If the coating amount is less than 2.5 g / m ^2, it is difficult for the height of the protrusions formed to be 2.5 μm or more, while 35 g
If it exceeds / m ² , it is also difficult to form protrusions of 25 μm or less.

After laminating such a photosensitive resin 57 on the surface layer 53, a predetermined pattern is irradiated with energy rays to form a dot-shaped exposed portion (FIG. 5d).

The exposure method of the predetermined pattern shape is not limited in the present invention. For example, a halftone dot-shaped exposed portion is formed by irradiating an energy ray (indicated by an arrow) through a mask 7 having a window 6 in a predetermined pattern shape. Can be formed. In this case, the size of the exposed portion 58 is 5 to 50 μm.
Exposure is performed so that 20 to 70% of the area of the front surface layer is occupied by the protrusions 56 (FIG. 5e).

Ultraviolet rays are usually used as the energy rays.
This is because, for example, in the case of a resin that is exposed to visible light, the storage and exposure steps become complicated and it is not practical.

The exposed portion 58 thus exposed becomes insoluble in the etching liquid (FIG. 5e), and the projection 56 can be formed by removing the non-exposed portion 59 by etching or the like (FIG. 5f).

This etching is performed, for example, on the part not exposed to the etching solution.
This is done by dissolving 59. Such an etching solution varies depending on the type of the photosensitive resin, but examples thereof include weak alkaline water such as sodium carbonate water and sodium hydroxide.

 Examples of the present invention will be described below.

Example After providing a compression layer on a base fabric, a surface rubber layer of unvulcanized NBR was formed and then vulcanized to form a surface layer.

This surface layer was polished under the conventional blanket surface polishing conditions to form a rough surface having a height of unevenness of 6 μm and a pitch of 70 μm, and then the two-liquid urethane was added to the rough surface at a rate of 10 g / m ^2. After applying a system adhesive and drying, an APR resin (photosensitive resin) (Asahi Kasei Co., Ltd.) was laminated and the photosensitive resin was exposed using a mask having a halftone dot pattern. The top surface dimension of the exposed portion was 25 μm and the density was 50%. The product exposed in this way is dipped in dilute sodium carbonate solution (etching solution) to remove the non-exposed part, and the height is 15μ.
m, and a surface layer having protrusions 56 having a top surface size of 25 μm at a density of 50% was formed.

After using the same base cloth and compression layer as this printing blanket and forming the surface layer using the same NBR,
A printing blanket, which was simply polished and provided with a rough surface, was manufactured for comparison, and the paper discharge property and halftone dot reproducibility were measured.

 The results are shown in Table 1.

Table 1 Paper discharge property (diagonal gap of 5 cm square after printing transfer) Example 54 mm Comparative example 1 28 mm Comparative example 2 25 mm Halftone dot reproducibility (50% halftone dot density) Example 0.63 Comparative example 1 0.67 Comparative example 2 0.78 ( EFFECTS OF THE INVENTION As is apparent from the above description, in the printing blanket according to the present invention, since the protrusions are provided with a predetermined size, density and height via the adhesive layer together with the rough surface, The synergistic effect of the protrusions and the protrusions has an advantage that the paper discharge property can be remarkably improved. In this case, the halftone dot reproducibility is equal to or slightly improved as compared with the conventional one, and there is an advantage that the printing blanket has extremely good performance. Further, the protrusions have good adhesive strength, and a printing blanket having excellent durability can be obtained.

Further, according to the method for producing a printing blanket according to the present invention, a printing blanket having the above-mentioned good halftone dot reproducibility and excellent paper discharge property has a large degree of freedom in design, good controllability, and easy It has the advantage of being manufacturable.

[Brief description of drawings]

1 is a schematic view of a printing machine, FIG. 2 is a sectional view showing the structure of a conventional printing blanket, FIG. 3 is a sectional view of an example of the printing blanket of the present invention, and FIG. 4 is a front view of the blanket. 5 and 5 are diagrams schematically showing an example of the method of the present invention. 5 ... Printing blanket, 53 ... Surface layer, 54 ... Rough surface, 55 ... Adhesive, 56 ... Protrusion, 57 ... Photosensitive resin, 58
…… Exposed area, 59 …… Unexposed area, 6 …… Window, 7 …… Mask.

Claims (2)

(57) [Claims] 1. A printing blanket having a surface layer on a base cloth, which is in contact with an object to be printed, the surface of the surface layer is polished to a rough surface, and a density of 20 to 20 is obtained via an adhesive layer.
A printing blanket, wherein cylindrical projections are provided at a ratio of 70%, and the top surface dimension of the projections is 5 to 50 μm and the height is 2.5 to 25 μm. 2. An oil-resistant or solvent-resistant polymer is laminated on a base fabric, vulcanized to form a surface layer, the surface layer is polished, an adhesive is applied, and then 2.5 to 35 g / Photosensitive resin is laminated at a ratio of m ² to form halftone dots of 5 to 50 μm and a density of 20 to
A method for manufacturing a printing blanket, which comprises exposing at a rate of 70% and removing the non-exposed portion by etching.