JP2013139113A - Offset printing blanket and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an offset printing blanket which is increased in ink-receiving performance, transferability to a material to be printed and adhesion to a substrate film, and also substantially free from warpage.SOLUTION: An offset printing blanket 1 is configured so that silicone rubber sheets 2 are stacked on both surfaces between which the substrate film 3 is interposed, and two layers of the silicone rubber sheets 2 are subjected to heat treatment at a temperature of 100°C or higher by an open system. A manufacturing method thereof is also provided.

Description

  The present invention relates to a blanket for offset printing and a method for manufacturing the same.

  Offset printing refers to a printing technique in which printing is performed without bringing a plate on which a print image is formed into contact with a printing material such as paper. In offset printing, ink from a plate is once transferred to a blanket, and then printed from the blanket onto a substrate. Offset printing has been conventionally used for printing on paper media such as newspapers and magazines because it can produce a large amount of the same printed material at a time, but in recent years it can be printed with relatively high accuracy. In addition to that, it is also expanding into the field of electronic components.

  The blanket has a structure in which a printing layer is laminated on a base material, and has a function of receiving ink from a plate with the printing layer. The main blanket has a structure in which a uniform thickness of silicone rubber is laminated on a polyethylene terephthalate base film. When manufacturing a blanket having such a structure, a method is used in which a base film is set inside a mold, a liquid silicone rubber material is poured from above the base film, and is integrally formed with the base film at room temperature. (For example, refer to Patent Document 1).

JP 2007-69412 A

  However, when the silicone rubber is only cured in the mold, it remains containing residues such as uncrosslinked low-molecular siloxane in the silicone rubber, and the crosslinking reaction of the silicone rubber siloxane does not proceed sufficiently. It cannot be said that the physical properties typified by mechanical properties and chemical properties required for the blanket printing layer are sufficient. As a result, ink acceptability is lowered, transferability to a printing material is lowered, and characters and the like during printing are dropped or deformed.

  Further, depending on the type of silicone rubber, the adhesiveness with a base film such as polyethylene terephthalate is low, and the base film and the silicone rubber may be peeled off during use. In order to improve the acceptability of ink, the transferability to the substrate, and the adhesion to the substrate film, it is possible to heat the blanket to sufficiently crosslink the silicone rubber on the substrate film. As a result, the silicone rubber shrinks more than the base film, resulting in curling. As a result, it is difficult to attach the blanket to the offset printing machine, and it is also difficult to perform high-precision printing.

  The present invention has been made in view of the problems as described above, and provides an offset printing blanket that improves ink acceptability, transferability to a printing material and adhesion to a substrate film, and has almost no warpage. The purpose is to provide.

  One form of the present invention for achieving the above object is formed by laminating a silicone rubber sheet on both surfaces sandwiching a base film, and heating two layers of the silicone rubber sheet at a temperature of 100 ° C. or higher in an open system. It is the blanket for offset printing made into the processed sheet | seat.

  In another embodiment of the present invention, at least one of the bonding surfaces of the base film and the silicone rubber sheet is a surface that is modified by surface excitation by ultraviolet light, corona, plasma, or excimer light, or silane. A blanket for offset printing in which at least one of the surfaces modified by a coupling agent or a primer is used.

  Another form of the present invention is a blanket for offset printing, wherein the base film is made of any one resin of polyethylene terephthalate, polycarbonate, polymethyl methacrylate, or polyimide.

  One embodiment of the present invention is a method for producing a blanket for offset printing, in which a silicone rubber sheet is laminated on both surfaces sandwiching a base film, and an uncured silicone rubber material is placed in a mold. A first molding step for curing and molding the silicone rubber sheet, a first heat treatment step for heat-treating the silicone rubber sheet after the first molding step at a temperature of 100 ° C. or higher in an open system, and a first heat treatment A blanket for offset printing comprising: a first lamination step in which a base film is laminated and bonded between two layers of silicone rubber sheets produced by the step.

  In another embodiment of the present invention, prior to the first laminating step, at least one of the bonding surfaces of the base film and the silicone rubber sheet after the first heat treatment step is subjected to ultraviolet light, corona, plasma, or excimer light. The offset printing blanket further includes a first modification treatment step that is a modified surface of at least one of a surface excited and modified by the surface, or a surface modified by a silane coupling agent or a primer. It is a manufacturing method.

  Another embodiment of the present invention is a method for producing a blanket for offset printing, in which a silicone rubber sheet is laminated on both surfaces sandwiching a substrate film, and the substrate film is formed between the formed silicone rubber sheets. And a second heat treatment step of heat-treating the three-layer laminate in an open system at a temperature of 100 ° C. or higher. This is a method of manufacturing a blanket for offset printing.

  According to another aspect of the present invention, the laminate manufacturing step further includes a second molding step in which an uncured silicone rubber material is cured in a mold and molded into a silicone rubber sheet, and the second molding step. And a second lamination step of laminating and bonding the base film so as to sandwich the two layers of the silicone rubber sheet.

  In another embodiment of the present invention, in the laminate production step, at least one of the bonding surfaces of the base film and the molded silicone rubber sheet is surface-excited by ultraviolet light, corona, plasma, or excimer light. A method for producing a blanket for offset printing, further comprising a second modification treatment step in which at least one of a modified surface and a modified surface by a silane coupling agent or a primer is used.

  According to the present invention, it is possible to provide a blanket for offset printing with improved ink acceptability, transferability to a printing material, and adhesion to a substrate film, and almost no warpage.

FIG. 1 shows a cross-sectional view when the blanket for offset printing according to the embodiment of the present invention is cut in the thickness direction. FIG. 2 shows an example of a manufacturing process of the offset printing blanket according to the embodiment of the present invention. FIG. 3 shows a change in the situation until an offset printing blanket is manufactured by the manufacturing process shown in FIG. FIG. 4 shows an example of a manufacturing process of the offset printing blanket according to the embodiment of the present invention, which is different from the manufacturing process shown in FIG. FIG. 5 shows a change in the situation until the offset printing blanket is manufactured by the manufacturing process shown in FIG. FIG. 6 shows an example of a manufacturing method of the offset printing blanket according to the embodiment of the present invention, which is a more specific example of the manufacturing process shown in FIG. FIG. 7 shows a change in the situation until the offset printing blanket is manufactured by the manufacturing process shown in FIG. FIG. 8 shows changes in the situation until the offset printing blanket is manufactured in another specific manufacturing process included in the category of the manufacturing process of the offset printing blanket shown in FIG.

  Next, preferred embodiments of the offset printing blanket and the manufacturing method thereof according to the present invention will be described.

1. Configuration of Offset Printing Blanket FIG. 1 is a cross-sectional view of the offset printing blanket according to an embodiment of the present invention cut in the thickness direction.

  A blanket 1 for offset printing according to an embodiment of the present invention is formed by laminating a silicone rubber sheet 2 on both surfaces sandwiching a base film 3.

(1) Base film The base film 3 constituting the offset printing blanket 1 is a resin film, and preferably polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA) or It is made of polyimide (PI), and more preferably made of PET, which is one of the materials from which a relatively inexpensive film having a uniform thickness can be obtained. The thickness of the base film 3 is preferably 50 to 400 μm, and more preferably 150 to 300 μm. The surface state of the base film 3 is not particularly problematic as long as the surface states of both sides of the film are the same, but preferably the surface roughness of the film is arithmetic average roughness (Ra) = 0.8 μm or less, more preferably , 0.6 μm or less is preferable.

(2) Silicone rubber sheet The silicone rubber sheet 2 constituting the offset printing blanket 1 is a rubber-like sheet having a siloxane bond (Si-O-Si) as a main skeleton, and is an uncured silicone rubber material. Is formed by crosslinking. Here, the silicone rubber material is a material obtained by polymerizing only silicone, that is, what is generally called dimethyl silicone rubber, methylphenyl silicone rubber, fluorosilicone rubber, or a silicone-modified polymer obtained by polymerizing silicone and an organic monomer, such as ethylene. It is broadly interpreted to include rubber obtained by modifying propylene rubber with silicone. The silicone rubber sheet 2 is a sheet that is heat-treated at a temperature of 100 ° C. or higher in an open system before or after lamination with the base film 3 (vulcanization) after molding. The molding temperature is appropriately changed depending on the type of silicone rubber material. In general, silicone rubber is a residue generated during the reaction even if it is molded at the molding temperature and molding time recommended by the material manufacturer, even if the crosslinking reaction is not complete or the crosslinking reaction is almost complete. Remains, and does not reach the original physical and chemical properties of the material. Therefore, a heat treatment step is provided in the present invention. The heat treatment temperature is set to 100 ° C. or higher in an open system in order to increase the crosslinking rate of the silicone rubber and to remove residues such as uncrosslinked low molecular siloxane. Further, when the silicone rubber sheet 2 is formed on both surfaces sandwiching the base film 3, the offset printing blanket is not flat as the offset printing blanket, and the offset printing blanket is substantially flat. It is important from the viewpoint of attachment to an apparatus, acceptance of ink from a plate during offset printing, and transfer of ink to a substrate to be printed. For this reason, in the case where the heat treatment step is performed after the base film 3 and the silicone rubber sheet 2 are laminated, the shape of the silicone rubber sheet 2 formed on both surfaces of the base film 3 is the same and the thickness is almost the same. It is desirable that The difference in thickness between the silicone rubber sheets 2 on both sides is preferably within 0.1 mm, more preferably within 0.07 mm, when viewed as the difference in average thickness of the silicone rubber sheets 2.

  In order to obtain a silicone rubber sheet 2 having a uniform thickness, a liquid silicone rubber material having a viscosity of 2500 Pa · s or less measured by “viscosity measurement method using a single cylindrical rotational viscometer” in accordance with JIS K7177. It is preferable to use it. However, in the case of using a press device or a calender device capable of applying a high pressure, a millable rubber whose state before curing is similar to that of an unvulcanized state of natural rubber or synthetic rubber may be used.

2. Method for Manufacturing Offset Printing Blanket FIG. 2 shows an example of the manufacturing process of the offset printing blanket according to the embodiment of the present invention. FIG. 3 shows a change in the situation until an offset printing blanket is manufactured by the manufacturing process shown in FIG.

  2 and 3, the silicon rubber sheet 2 is sufficiently cross-linked before the silicone rubber sheet 2 is laminated on the base film 3, and then the base film 3 is sandwiched. In this method, the silicone rubber sheet 2 is laminated. Hereinafter, the manufacturing method will be described.

  First, as shown in FIG. 3 (3A-1) and (3B-1), an uncured silicone rubber material 2a is supplied into the recess 11 of the lower mold 10 constituting the mold, The upper mold 20 constituting the mold is placed and cured at room temperature to mold the silicone rubber sheet 2b. In addition, as shown in (3A-2) and (3B-2) of FIG. 3, another silicone rubber sheet 2b is formed by performing the same operation in parallel or subsequently (step S110: second). One molding step). Next, after opening the upper mold 20 and the lower mold 10 and taking out the molded silicone rubber sheet 2b, as shown in (3C-1) and (3C-2) of FIG. The silicone rubber sheet 2b is heated at a temperature of 100 ° C. or higher in an open system (step S120: first heat treatment step). Next, a modification treatment is performed in which at least one of the bonding surfaces of the base film 3 and the heat-treated silicone rubber sheet 2 is a modified surface excited by ultraviolet rays, corona, plasma, or excimer light. It performs (step S130: 1st modification | reformation process step). Further, in the first modification treatment step, the surface of the base film 3 may be modified with a silane coupling agent or a primer.

  Next, as shown to (3D) of FIG. 3, it laminate | stacks so that both surfaces of the base film 3 may be pinched | interposed with the heat-treated silicone rubber sheet 2, and it bonds together (step S140: 1st lamination | stacking step). Prior to bonding with the base film 3, the silicone rubber sheet 2 is heated at a temperature of 100 ° C. or higher to be sufficiently crosslinked, and then bonded to the base film 3 so that the blanket 1 for offset printing is used. It will not be greatly warped.

  In the first modification treatment step, when a modification treatment for exciting the surface by ultraviolet rays, corona, plasma, or excimer light is performed on at least one surface of the silicone rubber sheet 2 and the base film 3, In the laminating step, the base film 3 and the silicone rubber sheet 2 can be bonded together at room temperature with hydrogen bonding. In addition, an adhesive mainly composed of a silicone component can also be used for bonding. Further, in the first laminating step, the silicone rubber sheet 2 is arranged on the base film 3 after the modification treatment in accordance with the required printing size, shape or position, and bonded to the base film 3. Can do.

  FIG. 4 shows an example of a manufacturing process of the offset printing blanket according to the embodiment of the present invention, which is different from the manufacturing process shown in FIG. FIG. 5 shows a change in the situation until the offset printing blanket is manufactured by the manufacturing process shown in FIG.

  The manufacturing method shown in FIG. 4 and FIG. 5 is a heat treatment at a temperature of 100 ° C. or higher after producing a three-layer laminate 1b having a base film 3 sandwiched between room temperature cured silicone rubber sheets 2b. This is a method for obtaining a blanket 1 for offset printing. Hereinafter, the manufacturing method will be described.

  As shown to (5A) of FIG. 5, the three-layer laminated body 1b laminated and bonded so that the base film 3 may be pinched | interposed between the shape | molded silicone rubber sheets 2b is produced (step S210: laminated body preparation) Step). Next, as shown in FIG. 5 (5B), the three-layer laminate 1b is heat-treated at a temperature of 100 ° C. or higher in an open system using an oven 30 or the like (step S220: second heat treatment step). . As a result, a blanket 1 for offset printing, in which the silicone rubber sheet 2 is laminated on both surfaces sandwiching the base film 3, is completed. In this manufacturing method, the shape of the silicone rubber sheet 2 formed on both surfaces of the base film 3 is the same shape and the thickness is substantially the same so that the blanket for offset printing after the heat treatment becomes substantially flat. Is desirable. The difference in thickness between the silicone rubber sheets 2 on both sides is desirably the same as the difference in thickness between the silicone rubber sheets 2 described above.

  FIG. 6 shows an example of a manufacturing method of the offset printing blanket according to the embodiment of the present invention, which is a more specific example of the manufacturing process shown in FIG. FIG. 7 shows a change in the situation until the offset printing blanket is manufactured by the manufacturing process shown in FIG.

  6 and 7, the uncured silicone rubber material 2 a is cured at room temperature to form a silicone rubber sheet 2 b, and then the molded silicone rubber sheet 2 b is laminated on both surfaces of the base film 3. The three-layer laminate 1b is manufactured, and then the three-layer laminate 1b is heat-treated. Hereinafter, the manufacturing method will be described.

  First, as shown in (7A-1) and (7B-1) of FIG. 7, an uncured silicone rubber material 2a is supplied into the recess 11 of the lower mold 10 constituting the mold, The upper mold 20 constituting the mold is placed and cured at room temperature to mold the silicone rubber sheet 2b. In addition, as shown in (7A-2) and (7B-2) of FIG. 7, another silicone rubber sheet 2b is formed by performing the same operation in parallel or subsequently (step S310: No. 2). Two molding steps). Next, a modification process is performed in which at least one surface of the bonded surface of the base film 3 and the molded silicone rubber sheet 2b is a modified surface excited by ultraviolet rays, corona, plasma, or excimer light. (Step S320: Second modification processing step). In the second modification treatment step, the surface of the base film 3 may be modified with a silane coupling agent or a primer.

  Next, as shown to (7C) of FIG. 7, the three-layer laminated body 1b laminated and bonded so that the base film 3 may be pinched | interposed between the shape | molded silicone rubber sheets 2b is produced (step S330 :). Second lamination step). The processes from step S310 to step S330 are processes in which the laminate manufacturing step (step S210) shown in FIG. Next, as shown in (7D) of FIG. 7, using an oven 30 or the like, the three-layer laminate 1b is heat-treated at a temperature of 100 ° C. or higher in an open system (step S220: second heat treatment step). . As a result, a blanket 1 for offset printing, in which the silicone rubber sheet 2 is laminated on both surfaces sandwiching the base film 3, is completed. Also in this case, as described above, the shape of the silicone rubber sheet 2 formed on both surfaces of the base film 3 is the same and the thickness is substantially the same so that the blanket for offset printing after the heat treatment becomes substantially flat. It is desirable. The difference in thickness between the silicone rubber sheets 2 on both sides is desirably the same as the difference in thickness between the silicone rubber sheets 2 described above.

3. As described above, the blanket 1 for offset printing according to the present embodiment is formed by laminating the silicone rubber sheet 2 on both surfaces sandwiching the base film 3, and the two layers. The silicone rubber sheet 2 is a sheet that is heat-treated at a temperature of 100 ° C. or higher in an open system. At least one surface of the bonding surface of the base film 3 and the silicone rubber sheet 2 is modified by surface excitation by ultraviolet rays, corona, plasma or excimer light, or by a silane coupling agent or primer. Even if the silicone rubber sheet 2 is heated at a temperature of 100 ° C. or higher to become a sheet having a high degree of cross-linking by using at least one of the modified surfaces, it adheres well to the base film 3. Is possible. In particular, when both surfaces of the bonding surface of the base film 3 and the silicone rubber sheet 2 are surface-excited by corona, plasma, or excimer light, an adhesive effect by hydrogen bonding is exhibited. By such a modification treatment, the offset printing blanket 1 has high durability. Moreover, since the silicone rubber sheet 2 having the same shape and a difference in average thickness of 0.1 mm or less is present on both surfaces of the base film 3, the single-sided silicone rubber sheet 2 is After being used as a printing layer, the silicone rubber sheet 2 on the other side can be used as a printing layer. Therefore, the offset printing blanket 1 can be used for a longer period of time.

  For example, as shown in FIGS. 2 and 3, the blanket 1 for offset printing was obtained by molding an uncured silicone rubber material 2 a and performing heat treatment at a temperature of 100 ° C. or higher in an open system. It is manufactured through a manufacturing process in which a base film 3 is laminated between two layers of silicone rubber sheets 2 and bonded together. For this reason, the blanket 1 for offset printing has high ink acceptability, excellent transferability to a printing material, high adhesion to the base film 3, and little warpage. In addition, since the base film 3 does not exist during the heat treatment of the silicone rubber sheet 2b, even if the material is originally difficult to cure at low temperature or a material requiring a special curing process, such as a silicone-modified polymer, It can be cured by a method according to the material and can be used as a constituent material of the blanket 1 for offset printing. Furthermore, if the manufacturing method which bonds the silicone rubber sheet 2 after heat processing to the base film 3 is used, the base film 3 is not necessarily laminated | stacked on the base film 3 with the silicone rubber sheet 2 of the same area as it. There is a degree of freedom in which the silicone rubber sheet 2 having a required shape or size can be attached to the required position above. For this reason, optimization of the usage-amount of the silicone rubber material 2a and the cost reduction accompanying it are attained.

  Further, as shown in FIGS. 4 to 7, for example, the offset printing blanket 1 is manufactured by forming a three-layer laminate 1 b in which a room temperature-cured silicone rubber sheet 2 b is laminated on both surfaces of a base film 3. It is manufactured through a manufacturing process in which the layer stack 1b is heated at a temperature of 100 ° C. or higher in an open system. During the heat treatment, since the silicone rubber sheet 2b having the same shape and a difference in average thickness of 0.1 mm or less is present on both surfaces of the base film 3, the base film 3 and Even if the silicone rubber sheet 2b having a different linear expansion coefficient tends to contract greatly, the blanket 1 for offset printing with almost no warpage can be obtained without curling on one side.

4). Other Embodiments While the preferred embodiment of the offset printing blanket and the method for manufacturing the same according to the present invention has been described above, the present invention is not limited thereto and can be implemented with various modifications.

  FIG. 8 shows changes in the situation until the offset printing blanket is manufactured in another specific manufacturing process included in the category of the manufacturing process of the offset printing blanket shown in FIG.

  First, the same modification treatment as described above is performed on one surface of the base film 3. Next, as shown in (8A) and (8B) of FIG. 8, the base film 3 is laid in the recess 11 of the lower mold 10 with the modified surface facing up, and the uncured state is placed thereon. The silicone rubber material 2a is supplied, the upper mold 20 is placed thereon, the silicone rubber material 2a is cured at room temperature, and the base film 3 and the silicone rubber sheet 2b are integrally formed. Next, a reforming process is performed on the surface of the integrally molded body on the base film 3 side. Subsequently, another mold is prepared, and as shown in (8C) and (8D) of FIG. 8, the above-mentioned integrally molded body is placed in the recess 51 of the lower mold 50 constituting the mold. Place the film 3 side up, supply the uncured silicone rubber material 2a to the base film 3 side, place the upper mold 60 from above to cure the silicone rubber material 2a at room temperature Then, the base film 3 and the silicone rubber sheet 2b are integrally formed. Next, when the lower mold 50 and the upper mold 60 are opened, as shown in FIG. 8 (8E), a three-layer laminate in which the room temperature cured silicone rubber sheet 2b is laminated on both surfaces of the base film 3. 1b is obtained. In this case, since the heat treatment is reserved for the subsequent process, the silicone rubber sheet 2b formed on both surfaces of the base film 3 has the same shape, and the difference when viewed from the difference in average thickness is 0.1 mm. It is as follows. Next, as shown to (8F) of FIG. 8, the three-layer laminated body 1b is heat-processed by the temperature of 100 degreeC or more by an open system using oven 30 grade | etc.,. As a result, a blanket 1 for offset printing, in which the silicone rubber sheet 2 is laminated on both surfaces sandwiching the base film 3, is completed. Thus, even if the three-layer laminate 1b is manufactured in the mold, the same blanket 1 for offset printing as that obtained through the manufacturing steps shown in FIGS. 6 and 7 can be manufactured.

  When the base film 3 and the silicone rubber sheet 2 are bonded together, or when the silicone rubber material 2a is placed on the base film 3 and integrally molded, either the base film 3 or the silicone rubber sheets 2 and 2b are used. One bonded surface or both bonded surfaces can be modified with a silane coupling agent or primer. The corona surface treatment, the plasma surface treatment or the surface treatment using excimer light is preferably performed on both the bonding surface of the base film 3 and the bonding surface of the silicone rubber sheet 2, but either one of the surfaces. Can also be done. Furthermore, the modification treatment is not an essential step, and the base film 3 and the silicone rubber sheets 2 and 2b may be bonded together without any modification.

  The present invention can be used as a blanket for offset printing.

DESCRIPTION OF SYMBOLS 1 Blanket for offset printing 1b Three-layer laminated body 2 Silicone rubber sheet 2a Silicone rubber material 2b Silicone rubber sheet 3 Base film 10 Lower mold (one structure of mold)
20 Upper mold (configuration of mold)
50 Lower mold (one mold configuration)
60 Upper mold (one mold)

Claims (8)

It is composed by laminating silicone rubber sheets on both sides of the base film,
A blanket for offset printing, wherein the two-layer silicone rubber sheet is a sheet obtained by heat treatment at a temperature of 100 ° C. or higher in an open system.   At least one surface of the bonding surface of the base film and the silicone rubber sheet is modified by surface excitation by ultraviolet light, corona, plasma or excimer light, or modified by a silane coupling agent or primer. The blanket for offset printing according to claim 1, wherein the blanket is a modified surface of at least one of the formed surfaces.   The blanket for offset printing according to claim 1 or 2, wherein the base film is made of any one of polyethylene terephthalate, polycarbonate, polymethyl methacrylate, and polyimide. A method for producing a blanket for offset printing, in which a silicone rubber sheet is laminated on both surfaces sandwiching a base film,
A first molding step of curing the uncured silicone rubber material in a mold and molding the silicone rubber sheet;
A first heat treatment step of heat-treating the silicone rubber sheet after the first molding step at a temperature of 100 ° C. or higher in an open system;
A first lamination step of laminating and bonding the base film so as to sandwich the two layers of the silicone rubber sheet produced by the first heat treatment step;
The manufacturing method of the blanket for offset printing characterized by including these.   Prior to the first laminating step, at least one of the bonding surfaces of the base film and the silicone rubber sheet after the first heat treatment step is surface-excited by ultraviolet rays, corona, plasma, or excimer light. 5. The method according to claim 4, further comprising a first reforming treatment step for forming at least one of a modified surface and a modified surface by a silane coupling agent or a primer. The manufacturing method of the blanket for offset printing of description. A method for producing a blanket for offset printing, in which a silicone rubber sheet is laminated on both surfaces sandwiching a base film,
A laminate production step for producing a three-layer laminate laminated and bonded so as to sandwich the base film between the molded silicone rubber sheets,
A second heat treatment step of heat-treating the three-layer laminate at a temperature of 100 ° C. or higher in an open system;
The manufacturing method of the blanket for offset printing characterized by including these. The laminate manufacturing step includes
A second molding step of curing the uncured silicone rubber material in a mold and molding the silicone rubber sheet;
A second lamination step of laminating and bonding the base film so as to sandwich the two layers of the silicone rubber sheet produced by the second molding step;
The manufacturing method of the blanket for offset printing of Claim 6 characterized by the above-mentioned.   In the laminate production step, at least one surface of the bonding surface of the base film and the molded silicone rubber sheet is a surface that is modified by surface excitation by ultraviolet rays, corona, plasma, or excimer light, The offset according to claim 6 or 7, further comprising a second modification treatment step in which at least one modified surface of the surface modified by the silane coupling agent or the primer is used. A method of manufacturing a printing blanket.

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