JP2000001061A - Blanket for printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit a high porosity and uniform and excellent compression characteristics by curing a layer of an ordinary temperature curable urethane resin in which hollow fine spheres are dispersed and forming a compressive layer having a closed cell structure. SOLUTION: The blanket 1 for printing is formed in a sheet type by laminating foundation cloths 11 to 13 and providing a printing surface 16 on the cloths via a compressive layer 14 and a foundation cloth 15. The layer 14 is formed by using the cloth 13 or 15 in contact with the layer 14 as a substrate, coating the cloth 13 or 15 with an uncured curable urethane resin in which hollow fine spheres are displayed, and curing the resin. Residual layers for constituting the blanket are laminated on and beneath the resultant laminate, and vulcanizing the entirety, thereby completing the blanket of the sheet type. Thus, the blanket which exhibits a high porosity and has uniform and excellent compression characteristics can be efficiently manufactured in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing blanket.

[0002]

2. Description of the Related Art Recently, a so-called air-type printing blanket provided with a compressible layer having a porous structure, also made of an elastomer such as rubber, under a surface printing layer made of an elastomer such as rubber, It is becoming widespread.

[0003] The air-type printing blanket has a lower compressive stress at the nip deformation caused by pressure contact with a plate cylinder and the like and a change in the amount of distortion as compared with a conventional solid type blanket having no compressible layer. Since the fluctuation of the compressive stress is small, it is excellent in shock absorption, and has an advantage that it is excellent in preventing, for example, an impact generated when feeding a gear of a printing press from adversely affecting printing accuracy. .

In a solid type printing blanket, a so-called bulge is generated due to stress concentration on a surface printing layer at a nip deformation portion, and a registration error due to circumferential elongation, poor paper feed, double, halftone dot, and the like. Although printing defects such as pattern deformation may occur, according to the air-type printing blanket, the compressible layer acts to reduce stress concentration on the surface printing layer. There is also an advantage that occurrence of defects can be prevented.

[0005] In the above-mentioned air-type printing blanket, as a compressible layer having a porous structure, conventionally, particles of sodium chloride particles dispersed in a matrix rubber are formed into a layer, vulcanized, and then vulcanized. A layer having a continuous pore structure formed by a so-called leaching method in which particles are extracted with warm water or the like, and a layer in which a foaming agent that decomposes by heating to generate a gas is dispersed in matrix rubber are formed into layers. Formed by foaming a foaming agent at the same time as vulcanization of rubber by heating during vulcanization,
It is known to have an independent pore structure.

However, in the compressible layer formed by the latter method and having an independent pore structure, it is difficult to control the foaming of the foaming agent, and the size of each formed independent pore may vary. Or, in the foaming process, a plurality of pores communicate with each other to form a huge void, and as a result, the pore structure of the compressible layer becomes non-uniform and the compression characteristics vary, which adversely affects the printing characteristics. There was a problem.

In order to solve such a problem, it has been studied to form a compressible layer having an independent pore structure by using hollow microspheres in which a gas is sealed in a spherical shell made of a thermoplastic resin. Was. Since the above hollow microspheres are supplied in a form in which the shape and particle size are almost uniform,
It was considered that a compressible layer having a uniform pore structure and having no variation in compression characteristics could be obtained by forming a layer obtained by dispersing this in a matrix rubber and vulcanizing the matrix rubber.

However, it has been clarified that, in the above-mentioned structure, if the matrix rubber is vulcanized by heating and pressurizing under the same conditions as in the past, a compressible layer having excellent compression characteristics cannot be obtained.

That is, the shell formed of the thermoplastic resin as described above is softened and melted by heating at the time of vulcanizing the matrix rubber, and easily deformed and crushed by the pressure at the time of the vulcanization. For this reason, a uniform closed pore structure having a sufficient porosity was not formed in the compressible layer, and the compressive properties of the compressible layer were deteriorated.

[0010] Therefore, it has been studied to cure the matrix rubber without deforming or crushing the hollow microspheres, and various proposals have been made.

[0011] For example, Japanese Patent Publication No. 6-59749 discloses that a matrix rubber formed by dispersing hollow microspheres in a layer is formed at a temperature lower than the temperature at which a shell constituting the hollow microspheres softens and melts, at about 43 to 40%. At a temperature of about 77 ° C, 1-1
A method of forming a compressible layer by holding for a long time of 2 hours to primary vulcanize the matrix rubber without deforming or crushing the hollow microspheres is disclosed.

According to this method, the above-mentioned compressible layer is then laminated with another layer constituting the printing blanket, and finally subjected to secondary vulcanization to produce a printing blanket. Even if the shell constituting the hollow microspheres softens and melts or disappears due to compatibility with the matrix rubber even if the same high temperature and high pressure are applied, The matrix rubber around the hollow microspheres, which has been vulcanized to a certain extent, has a high porosity and uniform compressible layer with excellent compression characteristics in order to maintain the shape of the voids where the hollow microspheres were. It is said that a printing blanket provided with

However, this method requires an extremely long time for the primary vulcanization of the matrix rubber as described above, so that the productivity of the compressible layer and, consequently, the printing blanket is significantly reduced. was there. In addition, in order to perform primary vulcanization of the matrix rubber at the low temperature as described above, it is necessary to use a special vulcanization accelerator generally called a super-accelerator, which increases the production cost of a printing blanket. There was also a problem.

Therefore, in order to solve these problems,
Japanese Patent No. 2670188 discloses softening of a shell,
Using highly heat-resistant hollow microspheres having a melting temperature of 135 ° C. or higher, the primary vulcanization temperature of the matrix rubber is set to about 80 ° C.
~ 150 ° C and higher than the previous case, reducing the time of primary vulcanization to 1-6 hours,
It has been proposed to form a compressible layer using a general-purpose vulcanization accelerator without using a special super accelerator as described above.

[0015]

However, in the above method, the primary vulcanization temperature of the matrix rubber is close to the softening and melting temperatures of the shells constituting the hollow microspheres, and the vulcanization time is short. It is still long and the amount of heat applied to the hollow microspheres during vulcanization is large, so during actual vulcanization, the vulcanization reaction of the matrix rubber, softening of the shell, deformation of the hollow microspheres due to melting, and crushing are almost complete. At the same time, it has been clarified by the inventors' studies that the game progresses in a competitive manner.

For example, a layer of matrix rubber in which hollow microspheres are dispersed, which is a base of the compressible layer, is wound in a roll shape together with a single-layer base fabric supporting the layer, and vulcanized in a vulcanizing can. In the case of performing primary vulcanization of the compressible layer by a method in which the amount of heat received by the matrix rubber layer may vary greatly, as in the case of vulcanization, the surrounding matrix rubber is in the same compressible layer. Although sufficiently vulcanized, the hollow microspheres were already deformed and crushed, or the hollow microspheres were not deformed or crushed, but the surrounding matrix rubber was insufficiently vulcanized. During the secondary vulcanization process, the hollow microspheres are deformed and crushed.As a result, the porosity of the compressible layer in the printing blanket is greatly reduced, and the compression properties are varied depending on the location. Getting worse It has been found that some of it.

An object of the present invention is to provide a compressible layer having a high porosity, exhibiting uniform and excellent compression characteristics, and capable of being efficiently produced in a short time, so that there is no danger of lowering the productivity of a printing blanket. Another object of the present invention is to provide a new printing blanket.

[0018]

Means for Solving the Problems To solve the above problems, the present inventors have made it possible to cure at lower temperature and lower pressure in place of the conventional matrix rubber requiring high temperature and high pressure vulcanization. In addition, as a result of studying the use of a curable resin capable of exhibiting the same elasticity as the matrix rubber after curing, it was found that a room-temperature-curable urethane resin should be used, and the present invention was completed. I came to.

Therefore, the printing blanket of the present invention is characterized in that the compressible layer having an independent pore structure is formed by curing a room-temperature-curable curable urethane resin layer in which hollow microspheres are dispersed. It is assumed that.

According to the present invention, the room-temperature-curable curable urethane resin layer in which the hollow microspheres are dispersed is formed under pressure of, for example, 1 kgf / cm ² or less, or under non-pressure.
In addition, a compressive layer is formed only by causing a curing reaction under low temperature and low pressure.

In such a low-temperature, low-pressure, and short-time curing reaction, phenomena such as softening of a shell, deformation of hollow microspheres due to melting, and crushing, which occur when conventional matrix rubber is vulcanized, are hardly found. Since it does not progress, the formed compressible layer has a high porosity, is uniform, and exhibits excellent compression characteristics.

Further, since such a compressible layer is efficiently produced by the above-mentioned short-time curing reaction, there is no possibility that the productivity of the printing blanket is reduced.

1 Note that the aforementioned Japanese Patent Publication No. 6-59749
And Japanese Patent No. 2670188, respectively.
Include polyurethane as an example of matrix rubber
However, the term polyurethane here means that
From the above, so-called millable vulcanization at high temperature and high pressure
Refers to the required urethane rubber and cure as referred to in the present invention.
No mention is made of practically any urethane resin.
Absent. 0

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below.

The above-mentioned cold-setting curable urethane resin constituting the compressible layer in the printing blanket of the present invention includes the following two components: (a) a polyol, a polyamine and a mixture thereof, and (b) a polyisocyanate. And any curable urethane resin that can be cured at room temperature can be used. Specifically, for example, a so-called one-component moisture in which (A) a polyol and / or a polyamine is reacted with a polyisocyanate in a polyisocyanate-excess state, and a curing reaction is started by contact with moisture in the air. Two-component curable urethane resin comprising a curable urethane resin, a first component containing (B) a polyol and / or a polyamine, and a second component containing a polyisocyanate, and mixing the two components to start a curing reaction. , And the like.

Examples of the polyol constituting the above-mentioned room temperature-curable curable urethane resin include castor oil or polyether polyol, polyester polyol, carbonate polyol, acrylic polyol, epoxy resin polyol, silicone polyol, Polymer-based polyols such as fluorinated polyols, polybutadiene-based polyols, butadiene / acrylonitrile copolymer-based polyols, and polyurethane polyols obtained by chain-extending these polyols with polyisocyanates described below.

As the polyamine, for example, 3,
3'-dichloro-4,4'-diaminodiphenylmethane, an initial condensate of o-chloroaniline and formaldehyde, triethylenetetramine, hexamethylenediaminecarbamato, 4,4'-methylenebis-o-chloroaniline and the like. .

Examples of the polyisocyanate to be reacted with the above polyol and / or polyamine include, for example, hexamethylene diisocyanate, xylylene diisocyanate, tolylene diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, tetramethyl xylylene diisocyanate. Aliphatic, alicyclic, or aromatic diisocyanates such as isocyanate and hydrogenated diphenylmethane diisocyanate, or biuret, adduct, or isocyanurate multimers of these diisocyanates, or these polyisocyanates are described above. And a polyurethane polyisocyanate obtained by extending the chain with a polyol.

Of the above, polyamines have higher reactivity with polyisocyanates than polyols.
The storage stability of the one-component moisture-curable urethane resin described above decreases, and the so-called pot life after mixing the two components of the two-component curable urethane resin may be shortened, resulting in reduced workability. . Therefore, it is usually preferable to use a polyol, and it is more preferable to use a polyamine in combination with a polyol, rather than alone, to adjust the reaction rate.

The compressible layer is formed by a method similar to the conventional method of applying an unvulcanized rubber paste on a substrate and curing the same, because it is easy to divert production equipment. Preferably, for this purpose, the viscosity in the uncured state of the room-temperature-curable curable urethane resin comprising the above components is adjusted to about 100 to 100,000 cps, so that the curable urethane resin becomes liquid or paste. It is desirable to have a shape.

In order to adjust the viscosity of the curable urethane resin to the above range, the type and molecular weight of each component described above may be adjusted, or a solvent may be blended. Examples of such a solvent include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate and the like.

The curable urethane resin may contain various conventionally known additives. Examples of such additives include fillers such as carbon black, oils, pigments, and various stabilizers. The amount of these additives, considering the strength and elasticity of the compressible layer,
In total, 10 parts by weight of curable urethane resin
It is preferably less than 0 parts by weight, especially less than 43 parts by weight.

Examples of the hollow microspheres dispersed in the room-temperature-curable urethane resin include, for example,
Conventionally known various hollow microspheres having a shell formed of a thermoplastic resin, such as those disclosed in JP-A-59749 and Japanese Patent No. 2670188, can be used.

In particular, in consideration of oil resistance to printing inks, homopolymers of polymerizable monomers such as vinylidene chloride and (meth) acrylonitrile;
A copolymer of these monomers or a terpolymer or higher copolymer containing these monomers is preferred, and particularly, a terpolymer of vinylidene chloride, acrylonitrile and methyl methacrylate, or acrylonitrile, methacrylonitrile and methacrylic A terpolymer of methyl acid or the like is most preferably used. Although the particle size of the hollow microspheres is not particularly limited, in order to form a uniform independent pore structure in the compressible layer and to make the compressible layer excellent in the compressive properties, the hollow microspheres must Average particle size is about 10-20
It is preferably about 0 μm. The particle size is
In the case of the unfoamed hollow microspheres described below, this is the particle size after heating and foaming.

Specific examples of the hollow microspheres include, for example, the hollow microspheres of the Expancel series manufactured by Expancel. Hollow microspheres of the Expancel series, in a shell of a thermoplastic resin, an unfoamed one in which an organic solvent that forms the voids is sealed,
The above-mentioned organic solvent is vaporized by heating, and a foamed foam having a void formed inside the shell is supplied. In the present invention, any of these foams can be used.

When the former, unfoamed hollow microspheres are used, (1) before dispersion in the curable urethane resin, (2) after dispersion, before the curing reaction of the curable urethane resin, or
(3) In any of the steps of curing the curable urethane resin, it is preferable to vaporize the organic solvent in the shell by heating to expand the hollow microspheres to the above-mentioned particle size.

It is conceivable to foam the unfoamed hollow microspheres after curing the curable urethane resin. In this case, however, since the foaming is hindered by the elasticity of the cured urethane resin, the compressible layer is hardened. There is a possibility that a uniform closed pore structure having a sufficient porosity is not formed therein, and the compressive properties of the compressible layer may be deteriorated.

The mixing ratio of the hollow microspheres in the compressible layer is not particularly limited. However, considering the compression characteristics of the compressible layer, the volume ratio of the hollow microspheres M to the curable urethane resin U after curing is M / M. Expressed as U, M / U = 20/8
It is preferably in the range of 0 to 80/20, especially M
It is preferred that / U = 70/30 to 30/70.

The compressible layer is formed by curing an uncured curable urethane resin layer in which hollow microspheres are dispersed, formed on a base.

For example, the printing blanket 1 is shown in FIG.
(a) As shown in (b), a plurality of (three in the figure) base cloths 11 to 11
13 are laminated, a compressible layer 14 and one base fabric 15
In the case of a sheet type provided with a surface printing layer 16 through the above, the hollow microspheres are dispersed on the base fabric 13 or 15 which is in contact with the compressible layer 14 and which is either upper or lower. Apply uncured curable urethane resin,
The composition is cured under the conditions described above to form the compressible layer 14.

The remaining layers constituting the printing blanket are, for example, vulcanized on the upper and lower sides of the laminate (the laminate in which the compressible layer 14 is formed on one surface of one base fabric 13 or 15). After laminating with an adhesive or the like, the whole is vulcanized in the same manner as before using, for example, a continuous vulcanizer or a vulcanizing can to obtain a sheet-type printing blanket shown in FIGS. 1 (a) and 1 (b). Is completed.

On the other hand, the printing blanket is shown in FIGS.
As shown in FIG. 2, a non-foamed base layer 23 made of an elastomer such as rubber is provided on the outer peripheral surface of a cylindrical sleeve 21 via an adhesive layer 22, and an adhesive layer 24b is formed on the outer peripheral surface.
, A non-stretchable wire (such as a thread) 24a in the length direction
Is spirally wound to form a non-stretchable layer 24, and further, on its outer peripheral surface, a compressible layer 25 and a surface print layer 26 are laminated in this order, which is a so-called gapless type having no seams in the circumferential direction. If this is the case, the sleeve 2
On the outer peripheral surface of No. 1, an uncured urethane resin in which hollow microspheres are dispersed is applied on a substrate on which each layer from the adhesive layer 22 to the non-stretchable layer 24 is formed first. The composition is cured under the conditions described above to form the compressible layer 25.

Then, a layer of a rubber composition for a surface printing layer is laminated on the outer peripheral surface of the compressible layer 25 via, for example, a vulcanizing adhesive or the like, and then, for example, using a vulcanizing can or the like,
When the whole is vulcanized in the same manner as in the prior art, a gapless printing blanket shown in FIGS. 2A and 2B is completed.

The thickness of each of the above-mentioned layers including the compressible layers 14 and 25 may be the same as the conventional one.

That is, in the sheet type printing blanket shown in FIGS. 1A and 1B, the base fabrics 11 to 13 and
15 has a thickness of about 0.15 to 0.5 mm;
Is preferably about 0.1 to 0.8 mm, and the thickness of the surface printing layer 16 is about 0.05 to 2.0 mm. In the gapless type printing blanket shown in FIGS. 2A and 2B, the thickness of the base layer 23 is 0.2 to 1 mm.
0.0mm, the thickness of the non-stretchable layer 24 is 0.15 to
About 1.0 mm, and the thickness of the compressible layer 25 is 0.03-0.
About 8 mm, the thickness of the surface printing layer 26 is 0.1 to 0.6 m
m is preferable.

The curing conditions of the curable urethane resin are not particularly limited. Among them, the pressure is maintained while maintaining the shape of the hollow microspheres dispersed in the curable urethane resin,
In consideration of preventing crushing, the pressure is preferably 1 kgf / cm ² or less, particularly preferably 0.5 kgf / cm ² or less, and is cured in a non-pressurized (pressure-free) state without pressurizing, that is, in the air. Curing of the urethane resin is most preferable, because the pressurizing device can be omitted from the manufacturing equipment.

The curing is preferably carried out at normal temperature in consideration of maintaining the shape of the hollow microspheres dispersed in the curable urethane resin and preventing its deformation and crushing. In this case, there is also an advantage that an apparatus for heating can be omitted from the manufacturing facility.

At this time, the curable urethane resin around the hollow microspheres is sufficiently hardened, and thereafter, the shell constituting the hollow microspheres is softened by heat during the final vulcanization.
In order to maintain the shape of the voids where the hollow microspheres are maintained even after melting, it is preferable to set the curing time to about 10 minutes or more, particularly 15 minutes or more. If the curing time is less than 10 minutes, the cured urethane resin tends to be insufficiently cured. Further, if the curing time is too long, the productivity is reduced. Therefore, the curing time is preferably 2 hours or less, particularly 1 hour or less, particularly preferably 50 minutes or less.

That is, about 10 minutes to 2 hours, particularly about 15 minutes to 1 hour, especially 15 minutes to 5 hours from the start of curing.
After about 0 minutes have passed, it is desirable to carry out the next step of assembling a printing blanket and final vulcanization.

The curing of the curable urethane resin may be performed under heating in order to accelerate the curing reaction and shorten the curing time.

In this case, consideration should be given to improving productivity by shortening the curing time and maintaining the shape of the hollow microspheres dispersed in the curable urethane resin to prevent its deformation and crushing. After that, it is preferable to set the heating temperature and time, specifically, for example, about 40 to 150 ° C.
In particular, at a temperature of 120 ° C. or less, especially 100 ° C. or less, for about 10 to 50 minutes,
It is preferable to cure for about 30 minutes.

As described above, when the unexpanded hollow microspheres are heated and foamed simultaneously with the curing of the curable urethane resin, a large number of hollow microspheres dispersed in the curable urethane resin can be uniformly dispersed. In order to make the foam, the heating temperature should be within the above range, especially at least 60 ° C., especially
It is preferable to set the temperature to 0 ° C. or higher.

The formation of the compressible layer by curing the curable urethane resin can be carried out by using a continuous vulcanizer or a vulcanizer as in the prior art. , Can be performed in a short time, and has excellent productivity.
In addition, since it is completed at lower temperature and lower pressure than vulcanization of rubber, for example, when curing under pressure, an ordinary press molding machine may be used, and when heating under non-pressure, use an oven or the like. You may. Further, when neither pressure nor heating is performed, the compressible layer can be formed without any need for a curing device.

The layer structure of the printing blanket of the present invention is not limited to those shown in FIGS.
Changes can be made.

In short, as long as the compressible layer is formed by curing a room-temperature-curable curable urethane resin, other configurations are not particularly limited.

[0056]

The present invention will be described below based on examples and comparative examples.

Examples 1 to 5 << Synthesis of Polyurethane Polyol >> While stirring the following components in a nitrogen stream, 46 parts by weight of isophorone diisocyanate was added dropwise, and the mixture was reacted at 80 ° C. for 2 hours to obtain a polyurethane polyol. Synthesized.

(Ingredient) (parts by weight) * Polytetramethylene glycol 122 (PTMG650) * Trimethylolpropane 13 * Di-n-butylsulfilaurate 0.1 * Toluene 120 << The curable urethane resin for the compressible layer Preparation >> The polyurethane polyol synthesized above was used as the first component of the two-component curable urethane resin,
To 18 parts by weight of a commercially available curing agent (N3500, manufactured by Sumitomo Bayer Urethane Co., Ltd., isocyanurate of hexamethylene diisocyanate) as the second component and 6 parts by weight of carbon black as a reinforcing agent were added to 00 parts by weight. did. The viscosity of the urethane resin after blending was 500 cps.

Next, the same volume of hollow microspheres (Expancel 091DE manufactured by Expancel, Inc., the shell of which was made of acrylonitrile, methacrylonitrile, and methyl methacrylate) Consisting of a polymer,
Expanded hollow microspheres having an average particle size of 60 μm. ] And uniformly dispersed to prepare a curable urethane resin for a compressible layer.

<< Formation of Compressible Layer >> The curable urethane resin for the compressible layer prepared as described above was coated on one side of a 0.30 mm thick cotton cloth as the base cloth 13 among the layers shown in FIG. 1 (a). , After being applied to a thickness of 0.5 mm, cured under the conditions shown in Table 1 below, and then polished the surface thereof,
A compressible layer 14 having a thickness of 0.4 mm was formed.

[0061]

[Table 1] << Manufacture of printing blanket >> Rubber paste obtained by dissolving the following components in an appropriate amount of toluene was applied to two pieces of cotton cloth having a thickness of 0.30 mm as base cloths 11 and 12 among the layers shown in FIG. 1 (a). Was impregnated so as to have a thickness of 0.08 mm and dried, and then these two cotton cloths were laminated.

[0062] Next, the base fabric 1 having the compressible layer 14 formed on one side in the compressible layer forming step on the two base fabrics 11 and 12 described above.
3 was laminated with the compressible layer 14 facing up.

The thickness of the base cloth 15 is 0.25 m.
On one surface of a cotton cloth having a thickness of 0.4 mm, a rubber paste for a surface printing layer in which the following components were dissolved in an appropriate amount of toluene was applied so as to have a thickness of 0.4 mm, and dried.

(Components) (parts by weight) * Acrylonitrile-butadiene copolymer rubber 100 * Pigment 0.5 * Hydrous silica 20 * Titanium oxide 5 * Zinc flower 3 * Stearic acid 1 * Plasticizer 10 * Sulfur 2 * Vulcanization Accelerator 2 After laminating the above-mentioned base cloth 15 on the compressible layer 14 with the surface coated with the rubber paste for the front print layer facing up, the whole of the laminate is 3 kgf / cm ^2. Under pressure,
After heating at 150 ° C. for 10 minutes for vulcanization, the surface of the surface printing layer 16 was subjected to 10-point average roughness Rz [JIS B0
601 _-1982 ] to 3 to 6 μm.
A printing blanket 1 of a sheet type having an overall thickness of 1.95 mm and having the layer configuration shown in FIG.

Comparative Example 1 With respect to the same rubber paste impregnated in the base cloths 11 and 12, the hollow microspheres having the same volume as the solids in the rubber paste, that is, each component excluding the solvent, were used. FIG. 1 shows a mixture of Expancel 091DE manufactured by Expancel Co., Ltd.
(a) thickness of 0.30 as the base fabric 13 among the layers shown in FIG.
mm cotton cloth to a thickness of 0.5 mm, dried, and then pressed under a pressure of 3 kgf / cm ² for 15 minutes.
After heating and vulcanizing at 0 ° C. for 10 minutes, the surface was polished to form a compressible layer 14 having a thickness of 0.4 mm. ), And a sheet-type printing blanket 1 having an overall thickness of 1.95 mm was manufactured.

Observation of Compressible Layer In the manufacturing process of the printing blanket of each of the above Examples and Comparative Examples, the compressible layer immediately after formation and before the final vulcanization in combination with other layers was subjected to microtome. After cutting, the cut surface was observed with a microscope. Then, the presence or absence of deformation and crushing of the hollow microspheres dispersed in the compressible layer was confirmed.

Actual Machine Test The printing blanket of each of the above Examples and Comparative Examples was wrapped around a blanket cylinder of an offset printing machine [Model 560 manufactured by Ryobi Co., Ltd.], and printing was performed on coated paper under the following printing conditions. Was.

(Printing conditions) Printing speed: 10000 sheets / hour Ink: Trade name “Mark V New” manufactured by Toyo Ink Co., Ltd. Coated paper: Trade name “Utrilo Coat 110 kg” manufactured by Daio Kashiki Co., Ltd. Were examined, and the printing blankets of Examples and Comparative Examples were evaluated.

(Solid inking property) The solid portion of the printed matter was subjected to image analysis, and its standard deviation n was determined. The smaller the value of the standard deviation n, the better the solid inking property.

After the continuous printing of 100,000 sheets, the thickness of the compressible layer was measured, and the original thickness (= 0.4
mm) was calculated as the amount of settling of the compressible layer.

Table 2 shows the above results.

[0072]

[Table 2] As shown in the table, the printing blanket of each example has no deformation or crushing of the hollow microspheres as compared with the comparative example 1 having the conventional structure, and therefore the compressible layer has a high porosity and a uniform porous structure. It was confirmed that the printing characteristics were excellent.

[0073]

As described in detail above, according to the present invention,
A new printing blanket with a compressible layer that has a high porosity, exhibits uniform and excellent compression characteristics, and can be efficiently manufactured in a short time, so that there is no danger of reducing the productivity of the printing blanket. It has a unique effect of being able to do so.

[Brief description of the drawings]

FIG. 1 is a diagram showing a sheet-type printing blanket as an example of an embodiment of the printing blanket of the present invention. FIG. 1 (a) is a cross-sectional view in which main parts are enlarged, and FIG. (b) is a perspective view showing the whole.

FIG. 2 is a diagram showing a gapless type printing blanket as another example of the embodiment of the printing blanket of the present invention, wherein FIG. FIG. 1B is a perspective view showing the whole.

[Explanation of symbols]

 1,2 printing blanket 14,25 Compressible layer

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 23, 1998 (1998.6.2)
3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

[0023] The Contact, respectively Kokoku 6-59749 discloses described above, and Patent No. 2670188, JP-
Polyurethane is included in the examples of the matrix rubber, and the polyurethane here refers to a so-called millable type urethane rubber that needs to be vulcanized at high temperature and high pressure, based on the description before and after the polyurethane. No reference is made to the curable urethane resin at all .

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Kunmoto 4-34-16 Kaida, Nagaokakyo-shi, Kyoto (72) Inventor Akitaka Kimura 1-2-20 Tsukimiyamahoncho, Suma-ku, Kobe-shi, Hyogo F-term (reference 2H114 CA03 DA60 DA74

Claims (2)

[Claims] 1. A printing blanket provided with a compressible layer having an independent pore structure, wherein the compressible layer cures a layer of a room-temperature-curable curable urethane resin in which hollow microspheres are dispersed. A printing blanket characterized by being formed by: 2. A cold-curable urethane resin layer in which hollow microspheres are dispersed is 1 kgf / cm.
^2. The printing blanket according to claim 1, wherein the printing blanket is formed by curing under a pressure of ² or less or under no pressure.