JP2009083104A - Blanket for offset printing and method for manufacturing the same - Google Patents

Abstract

An offset printing blanket capable of preventing the surface of a substrate from becoming water-repellent when printing on the substrate is provided.
Silicon rubber is used as a material for the blanket 10 for offset printing. The surface of this silicon rubber is subjected to an electron beam treatment. Here, in the irradiation process of the electron beam, the electron beam is generated at an acceleration voltage in the range from 70 kV to 90 kV, and the dose of the electron beam irradiated to the silicon rubber is a value in the range from 4 kGy to 20 kGy. It is said. Thereby, when printing on the substrate, even if a portion of the surface of the silicon rubber where the ink has not transferred contacts the substrate, the contacted portion can be prevented from having water repellency. .
[Selection] Figure 6

Description

  The present invention relates to a blanket for offset printing using silicon rubber as an ink transfer medium and a method for producing the same.

  In recent years, in a semiconductor device manufacturing process, a technology for imparting functionality to various substrates by offset printing has been developed. Specifically, by utilizing an offset printing technique, a circuit pattern is formed on a substrate, or a black matrix or a pattern of three primary colors is printed on a glass substrate to form a color filter.

  In order to perform offset printing, first, an ink pattern is formed on a printing plate. Next, the ink formed on the printing plate is transferred to the blanket. Here, the blanket is attached to the blanket cylinder so as to cover the surface of the blanket cylinder. The surface layer of the blanket becomes an ink transfer medium. In general, synthetic rubber, urethane rubber, silicon rubber, other soft rubbers, and the like are used as materials for the ink transfer medium. Thereafter, the ink transferred to the blanket is transferred again to a predetermined substrate (printed material), whereby printing on the printed material is performed.

  In offset printing, ink remains on the printing plate when the ink is transferred from the printing plate to the blanket, and ink remains on the blanket when the ink is transferred from the blanket to the substrate. There is. As described above, since all of the ink formed on the printing plate is not necessarily printed on the printing material, it is difficult to faithfully reproduce the printing pattern formed on the printing plate on the printing material. This is not a major problem in commercial printing, which is intended to print on paper itself, but printing that adds functionality to the substrate, such as circuit pattern printing, color filter black matrix, and three primary color patterns However, this printing has been a big problem because high printing accuracy is required. Recently, in order to solve such a problem, a technique has been proposed in which the polarity of the surface layer of an offset printing blanket is changed between when ink is received and when it is transferred (see, for example, Patent Document 1). That is, by increasing the surface energy of the blanket surface layer during ink reception, the blanket can reliably receive the ink formed on the printing plate, while the surface energy of the blanket surface layer is increased during ink transfer. By making it low, the ink received by the blanket is easily peeled off, and is surely transferred onto the substrate.

JP 2000-229398 A

  By the way, when printing on a substrate using a blanket using silicon rubber as an ink transfer medium, when a portion of the silicon rubber surface where the ink has not transferred comes into contact with the substrate, the surface of the contacted substrate Has water repellency. That is, the surface of the substrate becomes partially water-repellent. In the manufacturing process of the semiconductor device, the processing of the substrate is not completed only by the printing, and other processing is performed on the substrate after the printing. Here, examples of such other processing include reprinting, application of an insulating film, adhesion with a resin, and the like. For this reason, if printing is performed again on a substrate whose surface has become partially water-repellent, an ink repelling phenomenon occurs, which may cause pinholes or create a place where printing is not performed. In addition, when an insulating film is applied onto a substrate whose surface is partially water-repellent, the thickness of the insulating film may become uneven or pinholes may occur. Furthermore, when a substrate whose surface is partially water-repellent and another substrate are bonded together with an adhesive, the bonding strength is weakened. As described above, there is a problem that various kinds of processing cannot be satisfactorily performed on a substrate whose surface is partially water-repellent.

  In order to solve such a problem, the surface of the substrate having water repellency may be made hydrophilic. As a hydrophilization technique, there is a saponification treatment or plasma treatment with a strong alkali at a high temperature. However, if the substrate surface is hydrophilized by saponification or plasma treatment, the number of processing steps increases and an expensive apparatus is required. Further, when a saponification treatment is performed, a strong alkali is used, which is dangerous for an operator and may adversely affect the substrate. For this reason, the realization of the blanket for offset printing which can prevent that the surface of a board | substrate becomes water-repellent when printing on a board | substrate is desired.

  The present invention has been made based on the above circumstances, and provides an offset printing blanket capable of preventing the surface of the substrate from having water repellency when printing on the substrate, and a method of manufacturing the same. It is for the purpose.

  In order to achieve the above object, the present invention provides a blanket for offset printing using silicon rubber as an ink transfer medium and a method for manufacturing the same, and the surface of the silicon rubber is subjected to an electron beam irradiation treatment. Yes. Here, in the electron beam irradiation process, an electron beam is generated at an acceleration voltage in the range of 70 kV to 90 kV, and the dose of the electron beam applied to the silicon rubber is a value in the range of 4 kGy to 20 kGy. It is said.

  By setting the acceleration voltage within the range of 70 kV to 90 kV, it is possible to generate a low energy electron beam and stop the penetration of the electron beam up to the surface and the surface layer of the silicon rubber. Moreover, by setting the dose of the electron beam irradiated to the silicon rubber to a value within the range of 4 kGy to 20 kGy, the low molecular silicon compound existing on the surface and surface layer of the silicon rubber is decomposed or converted into other large molecules. It is thought that it can be combined. For this reason, when performing printing on a glass substrate, for example, using a blanket for offset printing using silicon rubber that has been subjected to such electron beam irradiation treatment, a portion of the surface of the silicon rubber where ink has not transferred Even when it comes into contact with the glass substrate, low-molecular silicon compounds are not released from the silicon rubber surface of the contacted portion, so that the surface of the glass substrate in contact with the glass substrate is prevented from having water repellency. can do. Therefore, when the next process is performed on the glass substrate, the process can be performed satisfactorily.

  The blanket for offset printing according to the present invention is suitable for use for performing circuit printing or color filter printing on the surface of a glass substrate. For example, when a circuit printing is performed on a glass substrate using the offset printing blanket, and then a process such as applying a resin such as a polyimide resin to the glass substrate is performed, the surface of the glass substrate does not have water repellency. Therefore, the resin can be satisfactorily applied. In addition, when performing color filter printing on the surface of a glass substrate using the offset printing blanket, a plurality of printing operations are performed to print a black matrix or a pattern of three primary colors. After that, the surface of the glass substrate does not have water repellency, so that the black matrix and the pattern of the three primary colors can be printed on the glass substrate, and the color filter can be produced with high printing accuracy. .

  When the blanket for offset printing according to the present invention is used, it is possible to prevent the surface of the substrate from having water repellency when printing on the substrate.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1A is a schematic perspective view of an offset printing blanket according to an embodiment of the present invention, and FIG. 1B is a schematic perspective view of an offset printing blanket attached to a blanket cylinder.

  The offset printing blanket 10 of this embodiment is itself formed in a sheet shape as shown in FIG. This offset printing blanket 10 is used as an ink transfer medium in the offset printing technique. The size of the offset printing blanket 10 is determined according to the size of the substrate. At the time of offset printing, the sheet-like offset printing blanket 10 is attached to the blanket cylinder 20 so as to be wound around the surface of the blanket cylinder 20 as shown in FIG.

  In this embodiment, the offset printing blanket 10 is used to perform printing for imparting functionality to various substrates in the manufacturing process of the semiconductor device. Specifically, using the offset printing blanket 10, circuit printing for forming a circuit pattern on a substrate, color filter printing for forming a black matrix or a pattern of three primary colors on a glass substrate, and the like are performed.

  Further, silicon rubber is used as a material for the offset printing blanket 10. In this embodiment, the silicon rubber is subjected to a process of irradiating an electron beam. That is, the blanket 10 for offset printing of this embodiment is manufactured by irradiating the surface of the silicon rubber with an electron beam after producing the sheet-like silicon rubber. Here, in the electron beam irradiation process, the electron beam is generated at an acceleration voltage in the range of 70 kV to 90 kV, and the dose of the electron beam applied to the silicon rubber is set to a value in the range of 4 kGy to 20 kGy. Yes. This electron beam irradiation process will be described in detail later.

  Next, a printing process using the offset printing method will be briefly described. FIG. 2 is a diagram for explaining a printing process by the offset printing method. First, an ink pattern is formed on the printing plate 30. Here, as an ink material, a material corresponding to a substance to be formed by printing on a substrate which is a substrate is used. Next, as shown in FIG. 2A, the ink formed on the printing plate 30 is transferred to the offset printing blanket 10 by rotating the blanket cylinder 20 on the printing plate 30. That is, the surface layer of the offset printing blanket 10 is an ink transfer medium. After that, as shown in FIG. 2B, the offset printing blanket 10 and the blanket cylinder 20 to which the ink has been transferred are moved to the place where the substrate 40 that is the printing object is disposed. Then, as shown in FIG. 2C, the ink transferred to the offset printing blanket 10 is transferred again to the substrate 40 by rotating the blanket cylinder 20 on the substrate 40. Thus, printing on the substrate 40 is completed.

  Next, the electron beam irradiation apparatus used when manufacturing the blanket 10 for offset printing of this embodiment is demonstrated in detail. FIG. 3 is a schematic configuration diagram of the electron beam irradiation apparatus, and FIG. 4 is a schematic circuit diagram of an electron beam generator of the electron beam irradiation apparatus.

  An electron beam irradiation apparatus 100 shown in FIG. 3 is used when manufacturing the offset printing blanket 10 of the present embodiment, and includes an electron beam generation unit 110, an irradiation chamber 120, an irradiation window unit 130, A conveying means 140. In this embodiment, the processing which irradiates an electron beam to a sheet-like silicon rubber (to-be-processed object) is performed using this electron beam irradiation apparatus.

As shown in FIG. 3, the electron beam generator 110 includes a terminal 111 that generates an electron beam and an acceleration tube 112 that accelerates the electron beam generated at the terminal 111 in a vacuum space (acceleration space). The terminal 111 includes a linear filament 111a that emits thermoelectrons, a gun structure 111b that supports the filament 111a, and a grid 111c that controls thermoelectrons generated in the filament 111a. Further, the inside of the electron beam generation unit 110 is 10 ⁻⁴ to 10 ⁻⁵ Pa by a pump or the like (not shown) in order to prevent electrons from colliding with gas molecules and losing energy and to prevent oxidation of the filament 111a. The vacuum is maintained.

  As shown in FIG. 3, the irradiation chamber 120 includes an irradiation space 121 for irradiating an object with an electron beam. The inside of the irradiation chamber 120 is maintained in an irradiation atmosphere having an oxygen concentration of 400 ppm or less. Further, the sheet-like silicon rubber that is the object to be processed is conveyed by the conveying means 140 from the left side to the right side in the irradiation chamber 120 in FIG. Specifically, a conveyor is used as the transport unit 140. The surroundings of the electron beam generator 110 and the irradiation chamber 120 are shielded from lead so that X-rays that are secondarily generated during electron beam irradiation do not leak to the outside.

  As shown in FIG. 3, the irradiation window section 130 includes a window foil 131 made of a metal foil, and a window frame structure 132 that cools the window foil 131 and supports the window foil 131. The window foil 131 separates the vacuum atmosphere in the electron beam generating unit 110 from the irradiation atmosphere in the irradiation chamber 120 and takes out the electron beam from the electron beam generating unit 110 to the irradiation chamber 120 through the window foil 131. It is. The metal used for the window foil 131 has mechanical strength that can sufficiently maintain the vacuum atmosphere in the electron beam generator 110, has a small specific gravity and a small thickness so that it can easily transmit the electron beam, and is heat resistant. It is desirable that it is excellent in An example of a metal used for the window foil 131 is titanium (Ti). Usually, a Ti foil having a thickness of about 13 μm is most often used because of easy mechanical handling.

  Further, in the electron beam irradiation apparatus 100, as shown in FIG. 4, a heating power source 151 for heating the filament 111a to generate thermoelectrons and a control for applying a voltage between the filament 111a and the grid 111c. DC power supply 152 for acceleration, and DC power supply 153 for acceleration which applies a voltage (acceleration voltage) between the grid 111c and the window foil 131 are provided.

  When the filament 111a is heated with current by the heating power supply 151, the filament 111a emits thermoelectrons, and these thermoelectrons are scattered in all directions by the control voltage of the control DC power supply 152 applied between the filament 111a and the grid 111c. Gravitate. Of these, only those that have passed through the grid 111c are effectively extracted as electron beams. The electron beam extracted from the grid 111 c is accelerated in the acceleration space in the acceleration tube 112 by the acceleration voltage of the acceleration DC power supply 153 applied between the grid 111 c and the window foil 131, and then the window foil 131. The sheet-like silicon rubber conveyed through the irradiation chamber 120 below the irradiation window 130 is irradiated. The current value due to the flow of the electron beam extracted from the grid 111c is referred to as a beam current. Therefore, the amount of electron beams increases as the beam current increases.

  In this embodiment, an electron beam irradiation device CB250 / 30/20 mA manufactured by Iwasaki Electric Co., Ltd. is used as the electron beam irradiation device 100. In such an electron beam irradiation apparatus 100, the effective irradiation width of the electron beam, that is, the irradiation width of the electron beam that can be taken out from the electron beam generator 110 into the irradiation chamber 120 through the window foil 131 and irradiate the object to be processed is 30 cm. That is, the electron beam irradiation apparatus 100 can perform processing on a workpiece having a width of 30 cm or less. For example, when producing a color filter used in a liquid crystal display device, a silicon rubber having a width of 5 cm to 300 cm is generally used as the silicon rubber for performing the color filter printing. For this reason, when performing the irradiation process of an electron beam with respect to the silicon rubber whose width | variety is larger than 30 cm, another large-sized electron beam irradiation apparatus will be used. Further, in this electron beam irradiation apparatus 100, the acceleration voltage can be set within a range from 80 kV to 250 kV, and the beam current can be set within a range from 0.5 mA to 20 mA. Furthermore, the moving speed of the conveyor that conveys the object to be processed, and hence the conveying speed of the object to be processed, can be set within a range from 5 m / min to 60 m / min.

  By the way, the energy given to the electron beam is determined by the acceleration voltage. That is, as the acceleration voltage is set higher, the energy obtained by the electron beam increases, and as a result, the electron beam can reach a deep position from the surface of the object to be processed. Therefore, the penetration depth of the electron beam into the object to be processed changes according to the set value of the acceleration voltage.

  Further, the amount of energy received by the object to be processed when the object is irradiated with an electron beam is represented by a value called absorbed dose. In order to give an appropriate absorbed dose to the workpiece, the beam current of the electron beam irradiation apparatus 100 is controlled. Normally, the beam current is adjusted by setting the heating power supply 151 and the acceleration DC power supply 153 to predetermined values and making the control DC power supply 152 variable. The absorbed dose D (kGy) received by the workpiece is obtained from the relational expression D = K · I / V using the beam current I (mA) and the conveyance speed V (m / min) of the workpiece. Here, K is a constant representing the electron beam generation efficiency. The greater the efficiency K, the more the generated electron beam can be irradiated onto the object to be processed. In this respect, efficiency K is an indicator of device performance. Further, the efficiency K varies depending on the acceleration voltage. For example, for the electron beam irradiation apparatus CB250 / 30/20 mA, the efficiency K when the acceleration voltage is 250 kV is “68”, and the efficiency K when the acceleration voltage is 80 kV is “35”. That is, as the acceleration voltage decreases, the efficiency K decreases, and the efficiency of extracting the electron beam into the irradiation chamber 120 decreases. In addition, when the process which irradiates a to-be-processed object with an electron beam is performed in multiple times, the absorbed dose which the said to-be-processed object receives becomes a value which multiplied D of the above type | formula by the process frequency (pass frequency).

  Actually, when irradiating an electron beam onto a sheet-like silicon rubber that is an object to be processed, various parameters in the electron beam irradiation apparatus are set to the following values. That is, the acceleration voltage is set to 80 kV, the beam current is set to 0.7 mA, the workpiece conveyance speed is set to 5 m / min, the number of treatments (pass number) is set to 1, and the oxygen concentration in the irradiation chamber 120 is set to 300 ppm or less. . At this time, the absorbed dose received by the silicone rubber is 35 × 0.7 (mA) ÷ 5 (m / min) = 4.9 (kGy) ≈5 (kGy).

  In this way, the blanket 100 for offset printing of this embodiment is obtained by performing the irradiation process of an electron beam on the surface of a sheet-like silicon rubber. The offset printing blanket 100 is wound around the surface of the blanket cylinder 20 as shown in FIG. At this time, the blanket 100 for offset printing is attached to the blanket cylinder 20 so that the surface on the side irradiated with the electron beam is located outside.

  Next, the present inventors set the surface state of the substrate for the substrate printed using the offset printing blanket 10 of the present embodiment and the substrate printed using the conventional offset printing blanket. Various tests were conducted.

  In these various tests, silicon rubber, which is a standard blanket product manufactured by Fujikura Rubber Industry, was used as a material for the ink transfer medium of the offset printing blanket. And the various parameters in electron beam irradiation apparatus CB250 / 30 / 20mA were set to the above-mentioned value, and the blanket 10 for offset printing of this embodiment was manufactured by irradiating the silicon rubber with an electron beam. On the other hand, a conventional blanket for offset printing was produced using the silicon rubber as it was without irradiating the silicon rubber with an electron beam. Moreover, the glass substrate was used as a board | substrate which is a test target object.

  Specifically, the present inventors conducted various tests for examining the surface state of the substrate, such as a test for evaluating the water repellency of the substrate surface, a test for evaluating the printing state when the substrate was printed again, and a resin for the substrate. The test which evaluates the application state in the case of apply | coating and the test which evaluates the adhesive strength of a board | substrate surface were done. FIG. 5 is a diagram for explaining the results of various tests conducted by the present inventors.

  First, a test for evaluating the water repellency of the substrate surface will be described. In this test, a glass substrate A1 on which a predetermined circuit printing was performed using the offset printing blanket 10 of the present embodiment and a glass substrate B1 on which the same circuit printing was performed using a conventional offset printing blanket. Were used as test objects. And the present inventors investigated whether the surface was water-repellent about each of glass substrate A1 and glass substrate B1. As a result, as shown in FIG. 5, about glass substrate B1, the part which the ink has not transferred by the said circuit printing among the surfaces was water-repellent. That is, the same result as the content already described as a problem of the conventional example was obtained. On the other hand, about the glass substrate A1, the surface maintained the surface state substantially equivalent to before performing the said circuit printing. Actually, the surface of the glass substrate A1 was not water-repellent. This is because in the offset printing blanket 10 of the present embodiment, even if a portion of the surface of the silicon rubber where the ink has not transferred contacts the glass substrate A1, the low molecular silicon compound from the silicon rubber surface of the contacted portion. I think that is because it does not release. That is, it is considered that the silicon rubber was modified so that the low-molecular silicon compound was not liberated from the surface by performing the electron beam irradiation treatment on the silicon rubber.

  Next, a test for evaluating a printing state when printing is performed again on the substrate will be described. This test was performed by performing color filter printing and examining the printing state. Specifically, in this test, the glass substrate A2 on which the black matrix was printed using the offset printing blanket 10 of the present embodiment and the black matrix were printed using the conventional offset printing blanket. The broken glass substrate B2 was used as a test object. Here, the portions of the glass substrates A2 and B2 where the ink has not been transferred by the printing of the black matrix are in direct contact with the portions of the blanket surface where the ink has not been transferred. Then, the inventors of the present invention performed offset printing of each pattern of the three primary colors on each of the glass substrate A2 and the glass substrate B2 to produce a color filter, and then examined the printing state of each pattern of the three primary colors. As a result, as shown in FIG. 5, with respect to the color filter manufactured using the glass substrate B2, the ink repelling phenomenon or pinholes may occur in the portion where each pattern of the three primary colors is printed. And there was a place where it was not possible to print partially. This is presumably because the portion is water-repellent. On the other hand, with respect to the color filter produced using the glass substrate A2, good printing results were obtained for the three primary color patterns.

  Next, a test for evaluating the application state when a resin is applied to the substrate will be described. In this test, a glass substrate A3 on which predetermined circuit printing was performed using the offset printing blanket 10 of the present embodiment, and a glass substrate B3 on which the same circuit printing was performed using a conventional offset printing blanket. Were used as test objects. And the present inventors applied predetermined resin on the surface about each of glass substrate A3 and glass substrate B3, and investigated the application state. Here, a polyimide resin was used as the resin. That is, the application of the resin corresponds to a processing step of forming an insulating layer on the substrate in the manufacturing process of the semiconductor device. As a result of this test, as shown in FIG. 5, the glass substrate B3 had polyimide resin coating spots on its surface. Moreover, pinholes were also generated in the polyimide resin. This is presumably because the surface of the glass substrate B3 is partially water-repellent. On the other hand, about glass substrate A3, the polyimide resin was apply | coated uniformly and the favorable application result was obtained.

Next, a test for evaluating the adhesive strength of the substrate surface will be described. In this test, a glass substrate A4 on which predetermined circuit printing was performed using the offset printing blanket 10 of the present embodiment, and a glass substrate B4 on which the same circuit printing was performed using a conventional offset printing blanket. Were used as test objects. And the present inventors performed the tension test in order to investigate adhesive strength about each of glass substrate A4 and glass substrate B4. In this tensile test, each glass substrate A4, B4 and a steel piece were bonded using an adhesive, and the adhesive strength was measured. Here, an epoxy resin was used as the adhesive. As a result, as shown in FIG. 5, the glass substrate B4 and the steel piece were peeled when pulled with a pressure of 40 kg weight / cm ² . That is, the adhesive strength of the glass substrate B4 was quite weak. This is also considered to be because the surface of the glass substrate B4 is partially water-repellent. On the other hand, the glass substrate A4 and the steel pieces were peeled when pulled with a pressure of 120 kg weight / cm ² . Therefore, it was confirmed that the adhesive strength of the glass substrate A4 is sufficiently large, and there is no problem with respect to the adhesive strength of the glass substrate A4.

  Thus, when printing on the substrate using the offset printing blanket 10 of the present embodiment, even if a portion of the surface of the silicone rubber where the ink has not transferred contacts the substrate, the contact is made. It was confirmed that the low molecular weight silicon compound was not liberated from the surface of the silicon rubber in part, and the surface of the contacted substrate could be prevented from becoming water repellent. Therefore, when the next process such as reprinting or resin application is performed on the substrate, the process can be performed satisfactorily.

  Next, the present inventors conducted an experiment to find out the electron beam irradiation conditions that can prevent the substrate surface from becoming water-repellent during printing.

  In this experiment, a blanket for offset printing produced using several silicon rubbers with different electron beam irradiation conditions was used as an experimental sample. In this experiment, as in the above various tests, a blanket standard product manufactured by Fujikura Rubber Industry was used as the silicon rubber, and an electron beam irradiation device CB250 / 30 manufactured by Iwasaki Electric Co., Ltd. was used as the electron beam irradiation device. / 20 mA was used. FIG. 6 is a diagram for explaining the three experimental samples used in this experiment and the experimental results for each experimental sample.

  Specifically, three offset printing blankets S1, S2, and S3 were used as experimental samples. The offset printing blanket S1 was manufactured using silicon rubber irradiated with an electron beam under irradiation condition 1, and the offset printing blanket S2 was irradiated with an electron beam under irradiation condition 2. The offset printing blanket S3 is manufactured using silicon rubber irradiated with an electron beam under irradiation condition 3. Here, as shown in FIG. 6, the irradiation condition 1 is that the acceleration voltage is 250 kV, the beam current is 10 mA, the transfer speed is 5 m / min, the number of treatments (pass number) is 2, and the oxygen concentration in the irradiation chamber 120 is The condition is 300 ppm or less. At this time, the dose of the electron beam received by the silicon rubber of the offset printing blanket S1 is 68 × 10 (mA) ÷ 5 (m / min) × 2 (times) = 272 (kGy). Irradiation condition 2 is that the acceleration voltage is 80 kV, the beam current is 7.1 mA, the transfer speed is 5 m / min, the number of treatments (the number of passes) is 1, and the oxygen concentration in the irradiation chamber 120 is 300 ppm or less. . At this time, the dose of the electron beam received by the silicon rubber of the offset printing blanket S2 is 35 × 7.1 (mA) ÷ 5 (m / min) × 1 (times) = 49.7 (kGy) ≈50 ( kGy). Furthermore, the irradiation condition 3 is a condition that the acceleration voltage is 80 kV, the beam current is 0.7 mA, the transfer speed is 5 m / min, the number of treatments (pass number) is 1, and the oxygen concentration in the irradiation chamber 120 is 300 ppm or less. . At this time, the dose of the electron beam received by the silicon rubber of the offset printing blanket S3 is 35 × 0.7 (mA) ÷ 5 (m / min) × 1 (times) = 4.9 (kGy) ≈5 ( kGy). That is, the irradiation condition 3 is the same as the irradiation condition set when the offset printing blanket 10 of this embodiment is manufactured as described above, and prevents the substrate surface from becoming water-repellent during printing. It is a suitable irradiation condition that can be achieved.

  The inventors performed predetermined printing on the glass substrates using these offset printing blankets S1, S2, and S3, and examined the surface states of the glass substrates. As a result, for the glass substrate printed using the offset printing blanket S1 and the glass substrate printed using the offset printing blanket S2, the surface of the glass substrate becomes partially water-repellent. It was. Therefore, it was found that the irradiation conditions 1 and 2 are not suitable irradiation conditions that can prevent the surface of the substrate from becoming water-repellent when performing offset printing on the substrate. On the other hand, the glass substrate printed using the offset printing blanket S3 has a surface state substantially the same as that before the printing, as can be seen from the test results of FIG. It was not water-repellent.

  The present inventors examined the results of such experiments, and considered suitable irradiation conditions. In order to prevent the surface of the substrate from becoming partially water-repellent when performing offset printing on the substrate, the portion of the silicon rubber surface that does not transfer ink contacts the substrate during the offset printing. Even so, it is necessary to prevent the low-molecular silicon compound from being released from the silicon rubber surface of the contacted portion. For this reason, in this embodiment, the silicon rubber is modified by irradiating the silicon rubber with an electron beam.

  By the way, since good results were not obtained under irradiation condition 1, and good results were obtained under irradiation condition 3, one of the conditions for obtaining good results was to set the acceleration voltage low. However, it is considered that the silicon rubber is irradiated with a low energy electron beam. When silicon rubber is irradiated with a low-energy electron beam, the electron beam penetrates only to the surface and surface layer of the silicon rubber. For this reason, in order to obtain good results, it is necessary to irradiate only the surface and the surface layer of the silicon rubber, not the entire silicon rubber, to improve only the surface and the surface layer of the silicon rubber. Assuming that good results were obtained when the accelerating voltage was actually set to 80 kV, it is thought that even if the accelerating voltage was set to 90 kV, only the surface and surface layer of the silicon rubber could be modified. It is done. It is also expected that good results will be obtained even when the acceleration voltage is set to a fairly low value (for example, 30 kV) such that the electron beam passes through the surface of the silicon rubber. However, from a practical viewpoint, it is desirable that the lower limit of the acceleration voltage is 70 kV. This is because the lower limit value of the accelerating voltage that can be adjusted is 70 kV for an industrially used electron beam irradiation apparatus that is commercially available. Some experimental electron beam irradiation apparatuses can adjust the acceleration voltage to a value smaller than 70 kV. However, in such an electron beam irradiation apparatus, the effective irradiation width of the electron beam is small. This is because it is very short and is not suitable for processing wide silicon rubber.

  In addition, since good results were not obtained under irradiation conditions 1 and 2, and good results were obtained under irradiation conditions 3, the other conditions for obtaining good results were silicon rubber. This is thought to be to reduce the dose given to the patient. If a dose of about 50 kGy or higher is applied to silicon rubber, the silicon rubber may not be modified as desired, or the silicon rubber may be destroyed. On the other hand, when a dose of about 5 kGy is applied to silicon rubber, it is considered that a low molecular silicon compound existing on the surface and surface layer of silicon rubber can be decomposed or bonded to other large molecules. That is, in this case, it is considered that a desired modification is performed on the silicon rubber so that the low molecular silicon compound is not released from the surface of the silicon rubber during offset printing. Naturally, it is considered that the silicone rubber cannot be modified as desired when a too small dose is given to the silicone rubber. Assuming that a good result was obtained when a dose of about 5 kGy was actually applied to silicon rubber, it can be considered that a good result can be obtained even if a dose of 4 kGy is applied to silicon rubber. On the other hand, based on the fact that good results were not obtained when a dose of about 50 kGy was given to silicon rubber and the knowledge and experience of the present inventors, the dose given to silicon rubber was at most It is expected that 20 kGy will give good results as well.

  Therefore, as a result of the above consideration, when the electron beam irradiation treatment is performed on the silicon rubber, the electron beam is generated at an acceleration voltage within the range of 70 kV to 90 kV and the dose of the electron beam irradiated on the silicon rubber is 4 kGy. It can be said that it is preferable to set the value within a range from 1 to 20 kGy. By setting the acceleration voltage within the range of 70 kV to 90 kV, a low energy electron beam can be generated and stopped at the surface and the surface layer of the silicon rubber, and the dose of the electron beam irradiated to the silicon rubber. This is because it is considered that a low molecular silicon compound existing on the surface and the surface layer of silicon rubber can be decomposed or bonded to other large molecules by setting the value to a value within the range of 4 kGy to 20 kGy. . For this reason, when printing on a substrate using a blanket using silicon rubber that has been subjected to such electron beam irradiation treatment, a portion of the surface of the silicon rubber where the ink has not transferred contacts the substrate. Even so, since the low-molecular silicon compound is not released from the silicon rubber surface in the contacted portion, it is possible to prevent the surface of the contacted substrate from becoming water-repellent.

  In the blanket for offset printing of the present embodiment, silicon rubber that has been subjected to a process of irradiating an electron beam is used as an ink transfer medium. Here, in the irradiation process of the electron beam, the electron beam is generated at an acceleration voltage of 80 kV and the dose of the electron beam applied to the silicon rubber is about 5 kGy. For this reason, when the blanket for offset printing of this embodiment is used, it is possible to prevent the surface of the substrate from becoming partially water-repellent when printing on the substrate. Therefore, when the next process is performed on the substrate, the process can be performed satisfactorily.

  In particular, the offset printing blanket of the present embodiment is suitable for use for performing circuit printing or color filter printing on the surface of a glass substrate. For example, when a circuit printing is performed on a glass substrate using the offset printing blanket and then a process of applying a resin such as a polyimide resin to the glass substrate is performed, the surface of the glass substrate is water-repellent. Therefore, the resin can be satisfactorily applied. In addition, when performing color filter printing on the surface of a glass substrate using the offset printing blanket, a plurality of printing operations are performed to print a black matrix or a pattern of three primary colors. After that, the surface of the glass substrate does not become water-repellent, so that a black matrix and a pattern of three primary colors can be printed on the glass substrate, and a color filter can be produced with high printing accuracy.

  In addition, this invention is not limited to said embodiment, A various deformation | transformation is possible within the range of the summary. For example, in the above embodiment, silicon rubber manufactured by Fujikura Rubber Industry was used, but this silicon rubber may be manufactured by another company. Moreover, in said embodiment, although the electron beam irradiation apparatus CB250 / 30 / 20mA by Iwasaki Electric Co., Ltd. was used, the electron beam irradiation apparatus made by other companies may be used. Furthermore, although said embodiment demonstrated the case where it printed on the surface of a glass substrate, this invention is not limited to a glass substrate, For example, you may print on the surface of a printed circuit board etc. .

  As described above, when the offset printing blanket according to the present invention is used, it is possible to prevent the surface of the substrate from partially having water repellency when printing on the substrate. Therefore, the offset printing blanket according to the present invention is suitable for use in performing printing for imparting functionality to various substrates, for example, circuit printing or color filter printing, in the manufacturing process of a semiconductor device.

(A) is a schematic perspective view of the blanket for offset printing which is one Embodiment of this invention, (b) is a schematic perspective view of the blanket for offset printing attached to the blanket cylinder. It is a figure for demonstrating the printing process by an offset printing system. It is a schematic block diagram of the electron beam irradiation apparatus used when manufacturing the blanket for offset printing of this embodiment. It is a schematic circuit diagram of the electron beam generation part of the electron beam irradiation apparatus. It is a figure for demonstrating the result of the various tests which this inventor etc. performed. It is a figure for demonstrating the three experimental samples used in the experiment which the present inventors etc. performed, and the experimental result with respect to each experimental sample.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Blanket for offset printing 20 Blanket cylinder 30 Printing plate 40 Substrate 100 Electron beam irradiation device 110 Electron beam generation part 111 Terminal 111a Filament 111b Gun structure 111c Grid 112 Acceleration tube 120 Irradiation chamber 121 Irradiation space 130 Irradiation window part 131 Window foil 132 Window frame structure 140 Conveying means (conveyor)
151 Heating Power Supply 152 Control DC Power Supply 153 Acceleration DC Power Supply

Claims (3)

  A blanket for offset printing using silicon rubber as an ink transfer medium, the surface of the silicon rubber being subjected to a process of irradiating an electron beam, and in the electron beam irradiation process, the electron beam A blanket for offset printing, wherein a line is generated at an acceleration voltage in a range of 70 kV to 90 kV and a dose of the electron beam applied to the silicon rubber is set to a value in a range of 4 kGy to 20 kGy.   The blanket for offset printing according to claim 1, wherein the blanket is used for circuit printing or color filter printing on the surface of a glass substrate. In the manufacturing method of offset printing blanket using silicon rubber as an ink transfer medium,
A first step of producing the sheet-like silicon rubber, and a second step of irradiating the surface of the silicon rubber obtained in the first step with an electron beam,
In the irradiation process of the electron beam in the second step, the electron beam is generated at an acceleration voltage within a range of 70 kV to 90 kV, and the dose of the electron beam irradiated to the silicon rubber is 4 kGy to 20 kGy. A method for producing a blanket for offset printing, characterized in that the value is within the range.

Images