JP2001232968A - Blanket for printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blanket for printing capable of printing with good solid inking on various type printing sheets by coping with diversification of printing and having no problem of flexibility at mounting. SOLUTION: The blanket for printing comprises a support layer having a compressible support and a compressible layer, and a surface print layer provided on the support layer. In this case, (1) an elastomer composition layer having a complex elastic modulus E* of 10 to 30 MPa (JIS K 7198) is provided between an upper layer foundation cloth and the compressible layer, or/and (2) an elastomer matrix for constituting the compressible layer has an elastomer matrix exhibiting the complex elastic modulus E*.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a blanket for offset printing.

[0002]

2. Description of the Related Art Conventionally, as a blanket in offset printing, a blanket provided with a surface printing layer made of synthetic rubber on a support layer made of a plurality of base fabrics has been used. Such a conventional blanket has good ink inking property on the surface printing layer, but when the pressure (printing pressure) at the time of printing increases, the halftone dot is deformed (particularly, the halftone dot becomes thicker).
This causes a problem that print quality is deteriorated due to the occurrence of printing.

Therefore, for the purpose of adjusting the printing pressure and suppressing the thickness of halftone dots and the like, there has been proposed a blanket for offset printing provided with a porous compressible layer inside.
This blanket has the advantage that the distortion caused by the printing pressure is absorbed by the compressible layer, so that the deformation of the blanket surface is reduced and the dot thickness is suppressed, and as a result, the print quality of the formed image is improved. is there. In particular, in recent years, a blanket provided with such a compressible layer has been widely used.

[0004]

However, in recent years, with the diversification of printing, printing on various types of papers has been required, and some papers with poor ink adhesion are included. I have. In that case, the printing pressure is adjusted or blankets having different compression characteristics are used, but it is still difficult to deal with them effectively. SUMMARY OF THE INVENTION An object of the present invention is to provide a printing blanket which is practically satisfactory in the inking property of ink even for printing papers of different paper qualities, and which has no problem in mountability to a printing press.

[0005]

Means for Solving the Problems and Effects of the Invention
After repeated investigations to solve the above problems,
A support layer having a shrinkable layer, and laminated on the support layer
Printing blanket that includes
Complex modulus E of fixed range^*Elastomer composition layer having
Between the upper base fabric and the compressible layer, and / or
And the complex elastic modulus E in the same specific range. ^*Elastomer with
-Offset by forming the compressible layer with the composition layer
Ink adhesion in high-speed printing on rotary press
The fact that it will improve
Ming completed.

That is, the present invention provides: 1) a printing blanket having a compressible support, a support layer including a compressible layer, and a surface printing layer thereon.
Complex elastic modulus E ^* is 10 to 30 MPa (E ^* is J
Based on the IS K7198 method, the elastomer composition layer having a dynamic strain of 10 Hz, an amplitude of 0.2%, an initial strain of 10%, and a temperature of 23 ° C. is measured). And / or between the active layer
(2) A printing blanket, wherein the elastomer matrix constituting the compressible layer has an elastomer matrix exhibiting the complex elastic modulus E ^* . 2) The blanket between the upper base fabric and the compressible layer. The printing blanket according to the above 1), wherein the thickness of the elastomer composition layer is 0.05 to 0.15 mm, 3) the complex elastic modulus E ^* of the elastomer composition layer is 12
The printing blanket according to the above 1) or 2), wherein the thickness of the compressible layer is from 0.1 to 0.6 mm, and the thickness of the compressible layer is from 0.1 to 0.6 mm. 1.45 thickness
The printing blanket according to any one of the above items 1) to 3), which is from 1.85 to 1.85 mm; 5) the elastomer composition is acrylonitrile butadiene rubber (NBR), hydrogenated NBR, chloroprene rubber (CR), polyurethane rubber , An acrylic rubber, a polysulfide rubber, and one or more rubbers selected from the group consisting of ASTM No. The printing blanket according to any one of the above 1) to 4), which contains one or more carbon blacks selected from N110 to N347 grades; and 6) the elastomer blank according to the present invention. The printing blanket according to any one of the above 1) to 5), wherein the amount of carbon black is 35 to 55 parts by weight based on 100 parts by weight of the elastomer material.

[0007] The printing blanket of the present invention is excellent in printing properties such as good ink depositability and suppression of dot thickening regardless of the type of printing paper even in high-speed printing. The flexibility at the time of attachment to the device does not cause any problem. The following can be considered as the reason. At the time of printing, by pressing the blanket against the substrate, the ink of the blanket is transferred to the substrate and printing is performed. In conventional blankets, improvement of the compressible layer was attempted by focusing on the compression direction of this blanket,
Blankets with moderate compression properties were produced.

In the present invention, the knowledge that the dynamic characteristics of the blanket in the horizontal direction of the blanket, that is, the direction in which the blanket is rotated when the blanket is mounted on the printing press, is also important for the printing characteristics. It is based on an improvement. That is, in addition to the foamable material constituting the compressible layer, in order to have an appropriate dynamic characteristic in the rotation direction, which is not seen in the conventional blanket, as described in the above item 1), a complex of a specific range is used. Printing characteristics and flexibility are improved by using the elastomer composition having the elastic modulus E ^* .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a printing blanket of the present invention will be described in detail. The printing blanket of the present invention comprises:
As described above, the surface printing layer, the support and the support layer having a compressible layer are laminated, and (1) a complex elastic modulus E ^* between the upper base fabric and the compressible layer ^. Is 10-3
And / or (2) the elastomer composition of the elastomer matrix constituting the compressible layer has an elastomer matrix having the complex elastic modulus E ^*. I do.

In the printing blanket of the present invention, when the elastomer composition layer of (1) is interposed, the compressible layer has an elastomer matrix having a complex elastic modulus E ^* specified in (2). Or any other conventionally known compressible layer. In the present invention, the complex elastic modulus E ^* of the elastomer composition in the above (1) and (2) needs to be 10 to 30 MPa,
More preferably, it is 12 to 25 MPa. Where E ^*
As described above, based on JIS K7198, dynamic strain 10 Hz, amplitude 0.2%, initial strain 10%, temperature 2
It shows the value under the measurement conditions of 3 ° C. If E ^* is less than the above range, the effect of improving printing characteristics such as solid inking property cannot be expected, while if it exceeds the above range, the compressible layer becomes too hard in the printing direction and a blanket is attached. Problems, such as difficulty in performing such operations.

As the elastomer material constituting the elastomer composition, a material having resistance to ink and washing liquid is preferably selected from rubber, resin, thermoplastic elastomer and the like. In particular, a rubber material can be preferably used in view of strength, workability, and cost. As the rubber material, for example, acrylonitrile butadiene rubber (N
One or more selected from the group consisting of BR), hydrogenated NBR, acrylic rubber (ACM), chloroprene rubber (CR), urethane rubber (U), and polysulfide rubber are preferably used.

The above-mentioned elastomer composition layer (1) is prepared by dissolving the above-mentioned material in a solvent (eg, toluene, methyl ethyl ketone, etc.) and applying it to a predetermined thickness, or dispersing the material to a predetermined thickness by a calender (rolling machine) or the like. After taking out, it can be formed by a method such as pressure bonding with a support. The thickness of the elastomer composition layer is 0.05 to 0.15 mm, more preferably 0.08 to 0.12 mm. If the ratio is below this range, the above-mentioned desired effects cannot be expected. If the ratio exceeds the above range, the compression direction of the compressible layer becomes too hard and the printing characteristics deteriorate.

Various additives are appropriately added to the elastomer composition together with the elastomer material. In the case of a rubber material, a vulcanizing agent and, in addition thereto, a vulcanization accelerator, a vulcanization accelerator, an antioxidant, a reinforcing agent, a filler, a softener and a plasticizer are appropriately added. In the present invention, in order to adjust E ^* of the elastomer composition layer to the above specific range, for example, an elastomer material or an additive may be appropriately selected. For example, the E ^* of the elastomer composition layer can be adjusted to fall within the above range by appropriately selecting the type and amount of carbon black as a reinforcing agent. Carbon black is, among others, ASTM (American Society for Testing and Materials) No. It is preferable to use one kind or two or more kinds belonging to grades 110 to 347. Specific examples include HAF (High Abrasion Furnace),
ISAF (Intermediate Super Abrasion Furnace),
And similar grades (eg, ISAF-L
S, ISAF-HS, N359, HAF-HS, HAF
-LS) and the like. The amount of carbon black to be added is usually 35 to 55 parts by weight, preferably 40 to 55 parts by weight, per 100 parts by weight of the rubber material.

Examples of the vulcanizing agent include organic sulfur-containing compounds such as tetramethylthiuram disulfide (TMTD) and N, N'-dithiobismorpholine, and sulfur. Further, an organic peroxide-based crosslinking agent can also be used as a vulcanizing agent. Specific examples of the organic peroxide-based crosslinking agent include tert-butyl hydroperoxide, di-te
rt-butyl peroxide, dicumyl peroxide, t
tert-butylcumyl peroxide, 1,1-bis (t
tert-butylperoxy) cyclododecane, 2,2-
Bis (tert-butylperoxy) octane, 2,5
-Dimethyl-2,5-di (tert-butylperoxy)
Hexane, 1,3-bis (tert-butylperoxyisopropyl) benzene, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, etc. Is raised.

The vulcanization accelerators include dibenzothiazyl disulfide (MBTS), N-oxydiethylene-2-benzothiazyl sulfenamide (OBS),
Thiazoles such as -cyclohexyl-2-benzothiazylsulfenamide (CBS) and N-tert-butyl-2-benzothiazylsulfenamide (TBBS) are cited as main accelerators; , 3-Diphenylguanidine (DPG), tetramethylthiuram monosulfide (TMTM), zinc dimethyldithiocarbamate (ZnMDC), zinc ethylphenyldithiocarbamate (ZnEPDC), and tetramethylthiuram mentioned as the vulcanizing agent Disulfide (TMTD) and the like can be appropriately compounded as a secondary accelerator.

Examples of the antioxidant include monophenolic compounds such as 2,6-di-tert-butyl-4-methyl (BHT) and 2,2'-methylenebis (4-
Bisphenols such as methyl-6-tert-butylphenol) and 2,5-di-tert-
Various antioxidants such as polyphenols such as butylhydroquinone, benzimidazoles, thioureas, phosphites, and organic thioacids can be used alone or in combination of two or more.

Examples of the filler include inorganic fillers such as calcium carbonate, hard clay, soft clay, silicic anhydride, barium sulfate, diatomaceous earth, talc, mica, asbestos, graphite, pumice, etc .; recycled rubber, powdered rubber, asphalts, styrene Organic fillers such as resin and glue are included. As the softener / plasticizer, conventional vegetable oil-based, mineral oil-based and synthetic product-based ones can be used as appropriate. For example, vegetable oil-based softeners include fatty acids (eg, stearic acid, lauric acid), which also function as vulcanization accelerators. Examples of the synthetic plasticizer include dioctyl adipate, dibutyl phthalate, and dioctyl phthalate.

Next, in the printing blanket of the present invention, the compressible layer of (2) has a complex elastic modulus E ^* of 10 to 10.
Although it is constituted as an elastomer having a pressure of 30 MPa, it can be prepared using the same elastomer material and additive components as in the case of the above (1). That is, in the compressible layer, a vulcanizing agent, a vulcanization accelerator and, if necessary, a thickening agent and the like are mixed with the rubber material to prepare an elastomer composition of an elastomer matrix. At this time, the complex modulus E of the elastomer after vulcanization of the composition is
The type and amount of the elastomer material and additives are appropriately selected or adjusted so that ^* becomes 10 to 30 MPa.

The compressible layer is formed by coating the base fabric layer with a filler, such as a foaming agent or hollow fine particles described below, if necessary, in addition to the above elastomer composition, and then vulcanizing. Formed by
Alternatively, a compressible layer can be formed by using a mixture of sodium chloride instead of the foaming agent and the hollow fine particles and eluting the salt with water or the like after vulcanization. The above materials are dissolved in a solvent (eg, toluene, methyl ethyl ketone, etc.) and applied to a predetermined thickness on the base fabric,
A compressible layer can be formed by a method such as calendering the material into a predetermined thickness using a calender or the like, and then pressing the material with a support. The thickness of the elastomer layer is 0.1 to 0.6 mm,
More preferably, it is adjusted to be 0.2 to 0.5 mm. If the ratio is below this range, the desired effect as described above cannot be expected. If the ratio exceeds the above range, the compression direction of the compressible layer becomes too hard, and the printing characteristics deteriorate.

The compressible layer is made of a porous elastic member as described above. The compressible layer has an independent pore structure in which each pore in the layer is independent, and a continuous pore structure in which each pore communicates with each other. There are things. In the present invention, either structure may be used, or both structures may be used together.
Among the above, the compressible layer having an independent pore structure is, for example, a method of dispersing a foaming agent that generates a gas by thermal decomposition in an unvulcanized rubber and foaming the rubber simultaneously with vulcanization of the rubber, or in the rubber. It is formed by a method of dispersing hollow fine particles (micro balloon method). On the other hand, the compressible layer having a continuous pore structure disperses extractable particles such as salt in unvulcanized rubber, and after vulcanization, uses a solvent (water in the case of salt) that does not affect the properties of the rubber. The particles are formed by a method of extracting the particles (leaching method).

The proportion of pores (voids) in the compressible layer (hereinafter referred to as
The “porosity” is usually adjusted to a range of 25 to 75%, preferably 30 to 60%, and more preferably 35 to 50%. If the porosity of the compressible layer is below the above range, the compressibility may be reduced and the adjustment of the printing pressure may be insufficient. Conversely, if the porosity exceeds the above range, the resilience may be reduced, causing settling, or the printing pressure required for printing may not be obtained.

In the printing blanket of the present invention,
As described above, via the elastomer composition layer of the above (1).
When the compressible layer has the complex elasticity specified in (2) above,
Rate E ^*Other than having an elastomeric matrix that exhibits
May be selected. In such cases
The hardness of the rubber used for the compressible layer is not particularly limited,
40 to 85 ° in JISA hardness, preferably 45 to 80
°, more preferably in the range of 50-75 °
Appropriate. If the hardness of the compressible layer falls below the above range, the pressure
Low resilience of the shrinkable layer and thus the printing blanket itself
And the printing pressure required for printing cannot be obtained.
May be lost. Conversely, if the hardness exceeds the above range,
There is a possibility that adjustment of printing pressure becomes insufficient due to reduced compressibility.
You.

In the printing blanket of the present invention, the constituent layers other than the above (1) and / or (2), that is, the support and the surface printing layer are formed by known means, for example, JP-A-10-175381, JP-A-10-175381. 10-181235
It can be formed by the method described in Japanese Unexamined Patent Application Publication No. 11-91260. For example, it can be formed as follows. Acrylonitrile-butadiene rubber (NB) is used as the rubber material constituting the surface printing layer.
R), hydrogenated NBR, chloroprene rubber (CR), polyurethane rubber, acrylic rubber, ethylene propylene rubber (EPM), and a terpolymer (EPDM) with ethylene-propylene and a gen component (EPDM).
Further, a mixture of these and a mixture of the synthetic rubber and the polysulfide rubber are also preferably used. The surface printing layer is, for example, the above rubber material, as described above, a vulcanizing agent, a vulcanization accelerator, a filler and the like are blended, and dissolved in a solvent such as toluene to form a rubber paste, the support layer It is formed by applying to the substrate by blade coating or the like.

Although the thickness of the surface printing layer is not particularly limited,
Usually, 0.05-0.8 mm, preferably 0.1-0.
It is appropriate to set the distance in the range of 6 mm, more preferably 0.2 to 0.5 mm. If the thickness of the surface printing layer is less than the above range, the pattern of the base fabric may appear on the printed image. Conversely, if the thickness exceeds the above range, the distortion during printing may become too large and the print quality may be degraded. The hardness of the surface printing layer is not particularly limited, but is suitably adjusted to a JIS A hardness of 40 to 75 °, preferably 50 to 65 °. If the hardness of the surface printing layer is less than the above range, the distortion during printing becomes too large, and the paper discharging property is reduced, and the registration accuracy may be reduced. Conversely, if the hardness exceeds the above range, the flexibility of the surface printing layer becomes insufficient, and the deformation of halftone dots may increase.

The surface roughness of the surface printing layer is not particularly limited and may be a conventional method.
It is preferably not more than μm. If the surface roughness of the surface printing layer exceeds the above range, there is a problem that the quality of the printed halftone dots is disturbed and the printing quality is reduced. Next, the support (also referred to as a reinforcing layer) usually comprises a base fabric layer known per se, and is obtained by impregnating a base fabric comprising a woven or non-woven fabric such as cotton, polyester, rayon or the like with a rubber paste. . Among these, a woven fabric subjected to stretch processing is preferable. Examples of the rubber paste for the base fabric layer include acrylonitrile-butadiene rubber (NBR) and acrylic rubber (AC
M), a rubber material such as chloroprene rubber (CR) or the like, which is mixed with a vulcanizing agent, a vulcanization accelerator, and, if necessary, a thickener, as described above.

The number of the base fabric layers may be appropriately set in accordance with the characteristics required for the product and the like, and is usually preferably 1 to 5 layers. In the present invention, for example, polyethylene terephthalate (PE) may be used instead of the base fabric layer.
T), a film made of a synthetic resin such as polycarbonate (PC), polyethersulfone (PES), or nylon, or a thin metal plate such as aluminum or stainless steel can also be used.

In the printing blanket of the present invention, when the support layer is produced by laminating the support with the elastomer composition layer interposed between the upper base fabric and the compressible layer. The thickness of the entire support layer is set according to the thickness of the elastomer composition layer, the compressible layer, and the like, and is usually 1.45 to 1.85 mm, preferably 1.50 to 1.75 mm. Is set in the range. The printing blanket of the present invention is obtained by coating the above-mentioned rubber paste for a surface printing layer via a primer layer on a support layer containing the elastomer composition layer, and pressing the thus obtained laminate at a predetermined pressure and pressure. It is produced by vulcanizing by heating and pressing at a temperature. The printing blanket thus obtained is used by being mounted on the peripheral surface of the cylinder of the blanket cylinder directly or via an underlay material.

[0028]

EXAMPLES The present invention will be described more specifically below with reference to examples along with comparative examples. <Evaluation Test Method> (1) Solid Filling Property A printing blanket was mounted on a cylinder of an offset rotary press, and the density distribution of the solid on each type of paper was visually judged according to the following criteria.

○ Uniformly good. △ Some unevenness. × Many irregularities. (2) Screen Thickness A blanket was mounted on a cylinder of an offset rotary press in the same manner as in (1) above, and the dot gain of the printed matter on the coated paper (the dot fatness) was observed with a microscope and judged according to the following criteria. .

○ No fatness at all △ Slightly fattening × Large fatness (3) Flexibility of blanket A blanket was prepared into a test piece having a width of 38 mm and a length of 150 mm, and one end was fixed while the other was fixed. Was pressed, and the stress was measured when tilted by 15 degrees from the original position. If the F value is too large, it is difficult to mount a blanket on a printing press, which is not practical. The flexibility was evaluated according to the following criteria according to the F value.・ F ≦ 800mN Good flexibility (○) ・ 800mN <F ≦ 1100mN Can be used without any problem in flexibility (△) ・ 1100mN <F Poor flexibility (×) (4) Measurement of complex elastic modulus E ^* Elastomer composition The rubber paste of the product is vulcanized at 150 ° C. to prepare a sheet having a thickness of 2 mm, according to JIS K7198 (Method A).
Based on the measurement method described in, dynamic strain 10 Hz, amplitude 0.2
%, An initial strain of 10%, and a temperature of 23 ° C. <Elastomer Compounding Composition> In the following Examples and Comparative Examples, the compounding compositions of the upper base fabric and the compressible interlayer elastomer composition or the composition used as the compressible interlayer elastomer composition were measured by the above method. Table 1 summarizes the complex elastic modulus E ^* at this time.

[0031]

[Table 1]

In Table 1, the antioxidants are 2,2 '
-Methylene (4-methyl-6-tert-butylphenol) was used, and N-tert-butyl-2-benzothiazolylsulfenamide (NS) was used as a vulcanization accelerator. Examples 1 to 3 FIG. 1 shows a configuration example of a blanket 10 for offset printing of the present invention. The blanket for printing is composed of three base cloths 13.
The surface printing layer 11 is arranged on a support made of a, 13b and 13c, an elastomer composition layer 15, a compressible layer 14, and a support layer 12 made of an upper base fabric 13d. . Here, the elastomer composition layer 15
Three printing blankets (Examples 1, 2 and 3) whose complex elastic modulus E ^* falls within the range specified in the present invention were produced as follows. (1) Preparation of Support Layer 12 As a base cloth, a mixed-spun fabric obtained by combining fibers of cotton cloth, polyester and rayon was used. A rubber paste obtained by dissolving the rubber compound for an adhesive layer shown in Table 2 in toluene and methyl ethyl ketone was paste-coated on the base fabric until the thickness became 0.05 mm. The three base cloths 13 thus obtained
a, 13b and 13c were pressed with a roll to obtain a base fabric layer (support).

[0033]

[Table 2]

In Table 2, dibenzothiazyl sulfide (DM) was used as the vulcanization accelerator ^* . Next, the compounding composition F shown in Table 1 was dissolved in toluene, and acrylonitrile-based resin hollow fine particles were further mixed so as to have a porosity of 50% to obtain a rubber paste for a compressible layer. On the other hand, each of the blended compositions A, B and C shown in Table 1 was dissolved in toluene to prepare a rubber paste of an elastomer composition for an upper base fabric and a compressible interlayer. Each rubber paste of the elastomer composition obtained here was applied to the base cloth 13d with a thickness of 0.1%.
mm, and dried by heating. A rubber compress (composition composition F) for the compressible layer 14 is pasted thereon, and the paste is pasted so as to have a thickness of 0.5 mm together with the elastomer composition layer. (14 + 15) was prepared. After drying, the base fabric layers (13a, 13b, 13c) prepared as described above and the rubber paste side of the compressible layer 14 were pressed to obtain the support layer 12 including the elastomer composition layer 15. (2) Preparation of Surface Printing Layer 11 As a rubber paste for the surface printing layer, a rubber compound shown in Table 3 below dissolved in toluene was used as the above-mentioned support layer 12.
A top surface printing layer 11 having a thickness of 0.4 mm was formed on the upper surface by coating.

[0035]

[Table 3]

In Table 3, the organic pigment ^* is epsilon blue LB510, the antioxidant ^** is 2,2'-methylenebis (4-methyl-6-tert-butylphenol),
Dibenzothiazyl disulfide was used as the vulcanization accelerator ^*** . (3) Molding The unvulcanized laminate obtained by the above method is subjected to a pressure of 1k.
vulcanized and molded at a temperature of 150 ° C. and g / cm ² respectively.
Next, the 10-point average roughness of the surface printing layer 11 is 3 to 6 μm.
Thus, the blanket 10 for offset printing was manufactured. In this manner, the three types of offset printing blankets 10 in which the complex modulus E ^* of the elastomer composition layer 15 is 12 (composition composition A), 24 (composition composition B) and 29 (composition composition C). I got These will be referred to as Examples 1, 2 and 3 in order. Comparative Example 1 A printing blanket was prepared in the same manner as in the above-mentioned Example except that the elastomer composition layer 15 was not provided. Comparative Examples 2 and 3 In the above Examples, the same procedures as in Comparative Examples 2 and 3 were carried out except that the blended compositions D and E shown in Table 1 were used as the rubber paste for the elastomer composition layer. A printing blanket was prepared.

Table 4 shows the results of the evaluation tests of the blankets prepared in Examples 1 to 3 and Comparative Examples 1 to 3.

[0038]

[Table 4]

As a result, based on the present invention, the elastomer composition layer 15 having a complex elastic modulus E ^* of 12, 24 and 29 MPa, respectively, was added to the upper base fabric 13 d and the compressible layer 14.
Each of the printing blankets of Examples 1 to 3 produced by interposing between them had good solid inking property regardless of the type of printing paper, and had no problem in flexibility. Embodiments 4 to 8 The configuration of the blanket 10 for offset printing of Embodiments 4 to 8 is shown in FIG. The printing blanket includes a support (base fabric layer) composed of three base fabrics 13a, 13b and 13c, a compressible layer 14, and a support layer 12 composed of base fabric 13d.
And a surface print layer 11 is disposed on the surface. Here, the elastomer composition of the elastomer matrix constituting the compressible layer 14 has a complex elastic modulus E.
^* Having an elastomer matrix exhibiting 10 to 30 MPa.

(1) Preparation of Base Fabric Layer As the base fabric, a blended woven fabric obtained by combining fibers of cotton fabric, polyester and rayon was used. On the above base cloth,
The rubber glue for the base fabric layer (rubber glue for the adhesive layer) shown in Table 1 was glued to a thickness of 0.05 mm. The three base fabrics thus obtained were pressed with a roll to obtain a base fabric layer (support). (2) Preparation of Compressible Layer The composition A, B or C shown in Table 1 above was dissolved in toluene, and acrylonitrile-based resin hollow fine particles were further mixed to obtain a rubber paste for a compressible layer. Acrylonitrile-based resin hollow microspheres calculated to have a predetermined porosity (see Table 5 below) were mixed.

The above-mentioned rubber paste for a compressible layer was applied on the base cloth 13d, and was squeezed to 0.4 mm to form a compressible layer. Here, in Example 4, the composition A in Table 1 was used, in Examples 5, 7, and 8, the composition B was used, and in Example 6, the composition C was used. The porosity of the compressible layer was 50% in Examples 4, 5 and 6, 30% in Example 7, and 70% in Example 8.
%.

After drying, the support layer was prepared by pressing the base cloth layer and the compressible layer on the rubber paste side. (3) Preparation of Surface Printing Layer As a rubber paste for the surface printing layer, a rubber composition shown in Table 3 dissolved in toluene was applied on each of the above-mentioned support layers, and a surface having a thickness of 0.4 mm was formed. A printing layer was prepared. (4) Molding Each of the unvulcanized laminates obtained by the above method was subjected to a pressure of 1
Vulcanization and molding were performed at kg / cm ² and a temperature of 150 ° C., respectively. Next, the 10-point average roughness of the surface printing layer is 3 to 6 μm.
To obtain a blanket for offset printing. Comparative Example 4 In the same manner as in Example 5 described above, except that the rubber paste (E ^{* after} vulcanization: 8 MPa) of the composition D shown in Table 1 was used as the elastomer composition for the compressible layer, the same procedure was performed. A printing blanket was prepared. The porosity of the compressible layer is 50%
Was adjusted. Comparative Example 5 The same procedure was performed as in Example 5 except that the rubber paste (E ^{* after} vulcanization: 35 MPa) of the compounding composition E shown in Table 1 was used as the elastomer composition for the compressible layer. A printing blanket was prepared. The porosity of the compressible layer is 50
%. Example 9 A blanket for offset printing was prepared according to the above-described example using the composition A shown in Table 1 as the elastomer composition between the upper base fabric and the compressible layer and the elastomer composition for the compressible layer. did. The porosity of the compressible layer was adjusted to 50%.

Table 5 shows the results of the evaluation tests of the blankets prepared in Examples 5 to 8, Example 9, and Comparative Examples 4 and 5.

[0044]

[Table 5]

As a result, in accordance with the present invention, each of Examples 4, 5 and 6 produced by incorporating an elastomer composition having a complex elastic modulus E ^* of 12, 24 and 29 MPa into the compressible layer, respectively. Regarding the printing blanket, regardless of the type of paper to be printed, the solid inking property was good, there was no practical problem with thickening halftone dots, and there was no practical problem with flexibility. Further, the printing blankets of Examples 7 and 8 in which the porosity of the compressible layer was 30% and 70%, respectively, had no problem in printing on each printing paper, and the flexibility was good. . Further, as in Example 9, by forming both the elastomer layer and the compressible layer provided between the upper base fabric and the compressible layer with the elastomer having the complex elastic modulus E ^* specified in the present invention. However, the printing characteristics and flexibility showed good results.

On the other hand, in the case of Comparative Example 4, the solid inking property on the finely coated paper was poor, and in Comparative Example 5, the halftone dot was large and the flexibility was poor.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a printing blanket of the present invention.

FIG. 2 is a cross-sectional view illustrating another configuration example of the printing blanket of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Printing blanket 11 Surface printing layer 12 Support layer 13a Base fabric 13b Base fabric 13c Base fabric 13d Upper base fabric 14 Compressible layer 15 Elastomer composition layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiko Kondo 3-6-9, Wakihama-cho, Chuo-ku, Kobe City, Hyogo Prefecture Within Sumitomo Rubber Industries, Ltd. (72) Inventor Hiromasa Okubo 3, Wakihama-cho, Chuo-ku, Kobe City, Hyogo Prefecture 6-9, Sumitomo Rubber Industries, Ltd. F-term (reference) 2H114 AA04 CA03 CA10 DA03 DA46 EA08 FA02

Claims (6)

[Claims] 1. A printing blanket having a compressible support, a support layer including a compressible layer, and a surface printing layer thereon, having a complex elastic modulus E ^{* of 10} to 30 MPa (where,
E ^* is based on JIS K7198 method and has a dynamic strain of 10H.
z, amplitude 0.2%, initial strain 10%, temperature 23 ° C.). (1) having an elastomer composition layer between the upper base fabric and the compressible layer, or And / or (2) a printing blanket, wherein the elastomer matrix constituting the compressible layer has an elastomer matrix having the complex elastic modulus E ^* . 2. The printing blanket according to claim 1, wherein the thickness of the elastomer composition layer between the upper base fabric and the compressible layer is 0.05 to 0.15 mm. 3. The complex modulus E of the elastomer composition layer.
The printing blanket according to claim 1 or 2, wherein ^* is 12 to 25 MPa. 4. The thickness of the compressible layer is 0.1 to 0.6 mm.
The printing blanket according to any one of claims 1 to 3, comprising a porous compressible layer of (1), wherein the total thickness of the support layer is 1.45 to 1.85 mm. 5. The composition according to claim 1, wherein the elastomer composition is one or more selected from the group consisting of acrylonitrile butadiene rubber (NBR), hydrogenated NBR, chloroprene rubber (CR), polyurethane rubber, acrylic rubber, and polysulfide rubber. Rubber and ASTM No. The printing blanket according to any one of claims 1 to 4, further comprising one or more carbon blacks selected from N110 to N347 grades. 6. The amount of carbon black in the elastomer composition is from 35 to 100 parts by weight of the elastomer material.
The printing blanket according to any one of claims 1 to 5, wherein the content is 55 parts by weight.