JP4018951B2 - Method for manufacturing printing blanket - Google Patents

Description

【００５５】
表１より明らかなように、未硬化状態で液状またはペースト状であるシリコーン系エラストマーを用いるとともに、エラストマー層を第１のシートと第２のシートとの貼り合わせと圧着によって形成したときは、印刷用ブランケットの表面に現れる欠点の数を極めて少なくする（実施例では観察されない程度にまで低減する）ことができた。すなわち、極めて平滑性の高い印刷用ブランケットを得ることができた。
【図面の簡単な説明】
【図１】本発明に係る印刷用ブランケットの製造方法を示す模式図である。
【符号の説明】
１０ 印刷用ブランケット
１１ 第１のシート
１２ 第１のフィルム基材
１３ （第１の）エラストマー層
１４ 第２のシート
１５ 第２のフィルム基材
１６ （第２の）エラストマー層
１７ エラストマー層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a printing blanket suitable for precision printing, in which a surface is subjected to a mirror finish or a predetermined matte treatment.
[0002]
[Prior art]
Offset printing is used in various fields, but it originally has the advantage that pattern formation can be realized by a simple method and at low cost, and in recent years, printing accuracy has been improved. Therefore, it is being used especially in the electronics field. Specifically, the use of offset printing has been attempted in fields that require extremely fine and high-precision pattern formation, such as electrical wiring patterns, phosphor patterns, and color filter and black matrix patterns.
[0003]
In the formation of a pattern by offset printing, the affinity between the surface printing layer of the printing blanket and the printing ink is one of the factors that greatly influence the printing accuracy of the pattern. Offset printing is a method of transferring an ink image on a printing plate to a printing blanket and further transferring the ink image onto a printing material to form a target pattern. This is because if the affinity with the printing ink is high, a phenomenon occurs in which the ink splits between the two. When such a phenomenon occurs, the pattern shape is disturbed or the film thickness of the pattern varies, and the printing accuracy is significantly reduced. For this reason, the surface printing layer of the printing blanket is made of, for example, silicone rubber. Thus, it is required to use a material having low surface energy and low affinity with printing ink (high ink releasability).
[0004]
Furthermore, in pattern formation by offset printing, the surface accuracy and thickness accuracy of a printing blanket are factors that greatly affect the printing accuracy. This is because if the size and thickness of the printing blanket are varied or the surface is rough, the shape of the pattern transferred onto the substrate to be printed is destroyed, or the printing position is shifted. In particular, in precision printing that forms a pattern with a line width and thickness of about several μm, even if the surface roughness of the printing blanket is kept to a very low level of about several μm, problems such as disconnection occur in the pattern. Can not be prevented.
[0005]
Therefore, various studies have been made on a method for producing a printing blanket (hereinafter referred to as a silicone blanket) using a silicone rubber for the surface printing layer from the viewpoint of improving the surface accuracy and thickness accuracy of the surface printing layer. As one of them, a so-called casting method is known in which liquid silicone rubber is poured into a mold to form a surface printing layer.
However, in recent years, there is a limit in terms of dimensional accuracy in manufacturing large-sized silicone blankets, which are in great demand in recent years, in terms of dimensional accuracy, and the cost and size of molds are enormous, making it difficult to put them into practical use. There is.
[0006]
As another method for producing a silicone blanket, a so-called coating method is known in which a liquid silicone rubber is stretched on a substrate using a knife or a roller. Since this method is simple in manufacturing equipment and can accommodate upsizing of equipment,
Large-size silicone blankets can also be produced with high accuracy.
However, in this method, since the surface is continuously exposed to the air when the silicone rubber is cured, the curing of the outermost surface of the silicone rubber is hindered by moisture, oxygen, and other impurities, and the entire silicone rubber is not cured. There is a problem that the printing becomes insufficient and adversely affects printing. There is also a problem that defects due to foaming or foreign matter are likely to occur on the surface.
[0007]
[Problems to be solved by the invention]
Incidentally, in JP-A-6-122186, JP-A-8-112981, JP-A-8-267952 and JP-A-2000-177266, silicone rubber is brought into contact with a release film such as a PET film. A method for producing a silicone blanket for vulcanization (crosslinking) and curing is disclosed.
According to the above method, the surface roughness of the silicone blanket can be made extremely small because the surface of the release film is a mirror surface and the mirror surface is transferred to the surface of the silicone rubber. .
[0008]
However, since the silicone blanket produced by the method described in the above publication has a compressible layer or is a complicated laminate, it has a conventional general structure. The base material part is stretched or contracted when the resin is bonded to the silicone rubber layer, or a gap is generated between the silicone rubber layer and the base layer due to the gas generated during the vulcanization of the silicone rubber. There is a problem that unevenness occurs in the surface. Therefore, the accuracy of the silicone blanket obtained by this method is insufficient as a blanket for precision printing.
[0009]
Accordingly, an object of the present invention is to provide a printing blanket with high surface smoothness and high ink releasability, which is suitable for printing a fine pattern with high accuracy, and a method for accurately producing the printing blanket. Is to provide.
[0010]
[Means for Solving the Problems and Effects of the Invention]
  A method for manufacturing a printing blanket according to the present invention for solving the above problems is as follows.
  Silicone on the first film substrateSeriesApply the lasterThe first film substrate and a cured first elastomer layerForming a first sheet;
  On the second film substrateSame as applied on the first film substratesiliconeSeriesApply the lasterThe second film substrate;UncuredA second elastomer layerForming a second sheet;
  SaidFirstSheet and saidSecond sheetWhenThe elastomer layers ofAnd curing to combine the first elastomer layer and the second elastomer layerAnd the process,
  CompleteFully curedAre unitedFrom the elastomer layerThe aboveFirstFilm substrateandSaidPeeling one of the second film bases;
HaveIt is characterized by that.
[0011]
  In the method for producing a printing blanket according to the present invention, the surface printing layer of the printing blanket is not formed only by, for example, a step of applying and curing an elastomer on a film substrate, but on a separate film substrate. Each with siliconeSeriesAfter applying lastmer, HardAn elastomer layer,UnhardenedChemicalIt is formed by superimposing and pressure-bonding the elastomer layer. Therefore, the surface portion of the elastomer layer that was exposed to air after being applied on the film substrate and left to stand and cured must be buried inside the finally obtained elastomer layer (ie, the surface printing layer). Thus, it does not appear on the surface of the printing blanket (especially the surface responsible for ink transfer).
[0012]
On the other hand, the surface that finally becomes the surface of the elastomer layer by peeling off the film substrate, that is, the surface that is responsible for the transfer of ink, is allowed to stand and cure in contact with the film substrate. Curing is not hindered by the inclusion of impurities. Therefore, the occurrence of defects is greatly suppressed. This is particularly useful when using a silicone-based or fluorine-based elastomer whose curing method is an addition type.
[0013]
Further, in the method of the present invention, bubbles generated during the curing of the elastomer are diffused from the respective surfaces when the first and second sheets are allowed to stand. Therefore, air bubbles remain between the elastomer layer and the film substrate, and the smoothness of the blanket surface is not impaired, and the blanket compressibility does not vary. Moreover, even if fine recesses are generated on the surface of the elastomer layer as the bubbles are diffused, the surface is a portion that is finally buried inside as described above, and therefore, the smoothness of the printing blanket surface is reduced. The impact on decline is extremely small.
[0014]
Furthermore, in the method of the present invention, since the elastomer layer is applied and cured in a state in contact with the film base material, the unevenness of the surface of the film base material is transferred to the surface appearing by peeling of the film base material. It becomes. Therefore, when a film substrate having extremely small surface irregularities is used, the surface flatness of the elastomer layer can be made extremely excellent. Normally, when the surface roughness of the elastomer layer is limited to about several μm when smoothed by means such as polishing, the surface of a highly flat film substrate is transferred. Although it varies depending on the surface roughness of the film substrate itself, the surface roughness of the elastomer layer can be reduced to about 0.01 to 1 μm (smoothed). On the other hand, by using a film substrate formed by adjusting the surface roughness to be moderately rough, fine irregularities such as rubbed glass can be provided on the surface of the elastomer layer.
[0015]
  Moreover, the elastomer layer formed by the method of the present invention has a very low surface energy and is excellent in ink releasability.SeriesThe laster is used.
  For the above reasons, according to the production method of the present invention, it is possible to obtain a printing blanket that has excellent surface flatness and ink releasability, and can transfer even a fine pattern with high accuracy. Can do.
[0016]
  In the present invention, when the first and second sheets are bonded, the elastomer layer in the first sheet is hard.ChemicalWhereas the elastomer layer in the second sheet is adjusted to beIs not yetAdjusted to stay in the cured state. IeThe secondThe first sheet is adjusted so that the degree of curing is higher than that of the second sheet.
[0017]
Here, the “cured state” refers to a state in which curing accompanying vulcanization / crosslinking of the elastomer is completed. The “semi-cured state” means a state in which fluidity is lost due to a certain degree of vulcanization / crosslinking of the elastomer or evaporation of the solvent. Further, the “uncured state” means a state in which elastomer vulcanization / crosslinking or solvent evaporation has not progressed and has fluidity.
By adjusting the cured state of the elastomer layers in the first and second sheets as described above, the first and second layers can be obtained without extra effort, that is, by simply pressing both layers and allowing them to stand. The sheet can be adhered with high accuracy.
[0018]
Therefore, the present invention is suitable as a method for producing a printing blanket for printing a fine pattern with high accuracy, and particularly as a method for producing such a printing blanket with a simple method with high accuracy.
[0019]
  Silicone used for forming an elastomer layer in the method for producing a printing blanket according to the present inventionSeriesLastomer,It is preferably liquid or pasty.
  When the elastomer is solid, it is necessary to dissolve or disperse it in a solvent in order to apply it, but in this case, there is a problem that the thickness accuracy after curing of the formed elastomer layer is not necessarily good. is there. On the other hand, when an elastomer that is originally liquid or pasty is used, such a problem does not occur, and an extremely smooth elastomer layer can be formed by self-leveling after coating. The self-leveling means “to flatten by standing”.
[0020]
  siliconeSeriesWhen the lastomer is liquid or pasty, the elastomer is preferably a room temperature curable elastomer.
  The curing method is preferably an addition reaction type from the viewpoint of improving the dimensional accuracy.
  When the elastomer is a room temperature curable type, heating and pressurizing processes are not required for the curing process of the elastomer, so that the printing blanket is not distorted by heating and pressurizing. The use of a room temperature curable elastomer is preferable for improving the thickness accuracy and surface accuracy of the printing blanket.
[0021]
  siliconeSeriesIn the case where the lastmer is liquid or pasty and is of room temperature curing type, the step of forming the first sheet is performed by applying silicone on the first film substrate.SeriesAfter applying lastmerThisUntil the elastomer loses its fluidity, leave it horizontally to cure the elastomer.The
  Details of the elastomer that can be used in the present invention are as described later.SeriesThe laster is applied after adjusting this, and then left to stand at room temperature (about 25 ° C.) for about 2 to 8 hours to cure to such an extent that fluidity is lost (that is, a semi-cured state)..
[0022]
In the method for producing a printing blanket according to the present invention, the first film substrate and / or the second film substrate is preferably a polyethylene terephthalate film.
This is because a polyethylene terephthalate (PET) film is excellent in dimensional stability and is preferable for forming an elastomer layer excellent in dimensional accuracy and thickness accuracy.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Next, a method for manufacturing a printing blanket according to the present invention will be described in detail with reference to the drawings.
One embodiment of a method for producing a printing blanket according to the present invention is shown in FIG.
FIG. 1 shows a process in the case where a liquid, room temperature curable elastomer is used as an elastomer, and the first film substrate is peeled after the elastomer is cured.
[0024]
  That is, first, liquid silicone is formed on the first film substrate 12.SeriesApply the laster and harden the elastomer layer by standing on a horizontal table (not shown).ChemicalState. In this way, the 1st sheet | seat 11 by which the 1st elastomer layer 13 is provided on the 1st film base material 12 is obtained [Fig.1 (a)].
  On the other hand, a primer layer (not shown) is applied and formed on the second film substrate 15, and then a liquid siliconeSeriesApply the laster and leave it on a horizontal table (not shown). Here, the resting is to the extent that the elastomer layer is smoothed by self-leveling, and the state of the elastomer layer 16Not yetHardChemicalStay in a state. In this way, the 2nd sheet | seat 14 with which the 2nd elastomer layer 16 is provided on the 2nd film base material 15 is obtained [FIG.1 (b)].
[0025]
  Next, the first elastomer layer 13 is superposed on the surface of the second elastomer layer 16, and further, the two elastomers are passed through a pair of rolls 20 and bonded together, thereby bonding them together. [FIG. 1 (c)].
  After the first sheet 11 and the second sheet 14 are bonded, the first film substrate 12 is peeled from the first sheet 11 [FIG. 1 (d)]. Thereby, the blanket 10 for printing which consists of the film base material 15 as a base layer and the elastomer layer 17 as a surface printing layer is obtained.
  When the elastomer to be used is not liquid or pasty, but is used by dissolving or dispersing in a solvent and is of a heat curable type, it is cured by heating, not by standing after the elastomer is applied. You can do it. In addition, the elastomer layer formed on the second film substrate can be adjusted by appropriately adjusting the evaporation of the solvent., Not yetHardChemicalIt may be adjusted to be in a state.
[0026]
[Film base]
In the present invention, the film substrate to be peeled after the bonding step is used as a substrate for forming the elastomer layer, and a member for adjusting the surface roughness of the elastomer layer (a member for surface mold taking) ). On the other hand, the film base material that remains without being peeled after the bonding step is used as a base material at the time of forming the elastomer layer, and acts as a so-called base material in the printing blanket finally obtained. It is.
[0027]
Therefore, both the first and second film substrates are required not to inhibit the curing of the elastomer used in the present invention and to have excellent dimensional stability.
Examples of the film substrate include resins such as polyethylene terephthalate (PET), vinyl chloride (PVC), polyethylene (PE), polypropylene (PP), (meth) acryl, polyimide, polycarbonate (PC), and polytetrafluoroethylene. Examples thereof include films used and films using metals such as stainless steel, aluminum, copper and nickel.
[0028]
Among these, PET film is particularly excellent in dimensional stability, and is excellent in the effect of adjusting the handleability and surface roughness as a member for adjusting the surface roughness of the elastomer layer (member for surface molding). And since it is excellent also in the workability of film itself, it is used suitably in this invention.
Impurities such as dust are likely to adhere to the surface of the film base, and these impurities cause defects on the surface of the elastomer layer. Therefore, when applying an elastomer on a film base material, it is preferable to wash the surface of the film base material.
[0029]
Of the first and second film substrates, the film substrate that is peeled after the bonding step is required to have particularly high surface flatness. This is because the surface of the elastomer layer after peeling off the film substrate becomes a surface responsible for ink transfer. Specifically, the flatness of the surface of the film base material peeled after the bonding step is preferably adjusted to a range of 0.01 to 1 μm in terms of ten-point average roughness (Rz). When the surface roughness of the film substrate exceeds the above range, the mirroring treatment for the elastomer layer may be insufficient. On the other hand, if the surface roughness of the film substrate is less than the above range, the degree of adhesion with the elastomer becomes extremely high, and the surface of the elastomer layer may be damaged when the film substrate is peeled off.
[0030]
Of the first and second film bases, the film base that is peeled after the bonding step is thin as long as it does not adversely affect the flattening process during the formation of the elastomer so that the peeling work can be easily performed. It is preferable to design. Usually, the thickness of the film base is set in the range of 0.05 to 1 mm, preferably 0.1 to 0.5 mm.
On the other hand, among the first and second film base materials, the film base material that remains without being peeled after the bonding step and finally becomes the base material of the printing blanket, is a mechanical material necessary as the base material. The thickness is appropriately set according to the strength and the thickness required for the printing blanket as a whole. Usually, the thickness of the said film base material is set to 0.1-1 mm, Preferably it is the range of 0.2-0.5 mm.
[0031]
Of the first and second film base materials, the film base material that will ultimately be the base material of the printing blanket is not strictly defined for the flatness of the surface, In order not to cause variation in the thickness of the elastomer layer formed on the surface, it is required to be flat to some extent. Specifically, the ten-point average roughness (Rz) is preferably adjusted to a range of 0.01 to 5 μm.
[0032]
Regardless of whether the first and second film substrates are peeled after the bonding step, it is required that the thickness variation is extremely small. If the thickness of the film base material varies, the thickness of the elastomer layer formed on the film base material may vary, or the smoothness of the surface may be hindered. As a result, the entire printing blanket This is because it may adversely affect the thickness and smoothness of the film.
[0033]
  [Elastomer]
  Silicone used in the present inventionSeriesExamples of the laster include silicone elastomers such as silicone rubber and fluorosilicone rubber.IsCan be mentioned.
  The elastomer used in the present invention may be solid, but in order to realize smoothing by self-leveling, for example, liquid silicone rubber (LSR) or the like is liquid or pasty in an uncured state. Are preferred.
[0034]
The elastomer used in the present invention is one that cures without requiring heating or pressurization, that is, one that cures at room temperature (about 25 ° C.), such as room temperature vulcanization type (RTV) silicone rubber. It is preferable for stabilizing the surface accuracy and dimensional accuracy of the elastomer layer.
Specific examples of the silicone elastomer used in the present invention include “KE1600”, “KE1300”, “KE1400”, “KE1402”, “KE10” manufactured by Shin-Etsu Chemical Co., Ltd., which are two-component RTV rubbers, “KE17”, “KE116”; “TSE3503”, “TSE3502”, “TSE3455T”, “TSE3450” manufactured by GE Toshiba Silicone Co., Ltd., and the like.
[0035]
  ThisWhen these elastomers are coated on a flat substrate and allowed to stand and cure at room temperature (about 25 ° C.), that is, without heat treatment, the elastomer layer should be easily handled. Specifically, in order to cure the surface of the elastomer layer to such an extent that the stickiness of the elastomer layer is eliminated, it is generally necessary to stand for about 2 to 8 hours, although it varies depending on the type of elastomer used.
[0036]
  The elastomer applied to the first and second sheets is,sameOne elastomeris there. ThisFirst and second sheetCrimping ofThus, both elastomer layers can be firmly combined.
[0037]
The viscosity of the elastomer used in the present invention is not particularly limited, but the viscosity is preferably low in order to sufficiently achieve smoothing by self-leveling during the formation of the elastomer layer. Specifically, the viscosity of the elastomer in an uncured state is preferably 10 to 600 Pa · s, and more preferably 30 to 300 Pa · s. If the viscosity of the elastomer exceeds the above range, curing may be completed before self-leveling is achieved, and the thickness accuracy of the elastomer layer may be adversely affected. On the other hand, when the viscosity of the elastomer is lower than the above range, the elastomer tends to flow and spread out to the surroundings at the time of application work, and it may be difficult to form a uniform layer.
[0038]
The time required for the elastomer to cure, that is, the pot life (pot life) of the elastomer is not particularly limited, but is preferably 10 minutes to 12 hours at room temperature (about 25 ° C.), preferably 30 minutes to 2 hours. It is more preferable that As the pot life is longer, smoothing by self-leveling can be steadily performed, which is advantageous in preventing the remaining of bubbles, but when the pot life is longer than the above range, it is disadvantageous in terms of work efficiency. On the other hand, when the pot life is less than the above range, the self-leveling may not be cured, which is not preferable in terms of work efficiency.
[0039]
You may mix | blend an organic peroxide type crosslinking agent with the said elastomer as needed.
The thickness of the elastomer layer formed on the first and second film bases is 0.05 to 2 mm, respectively, and the thickness of the elastomer layer after the first sheet and the second sheet are pressure-bonded is 0. Designed to be 3 to 2.5 mm. If the thickness of the elastomer layer formed on the first and second film bases exceeds the above range, the overlay accuracy may be reduced when the first and second sheets are bonded. On the other hand, if the thickness of the elastomer layer is less than the above range, the printing pressure will increase too much during printing, resulting in use. The thickness of the elastomer layer is preferably set in the above range from the viewpoint of printability.
[0040]
[Elastomer application process and curing process]
The elastomer may be applied to the surface of the film substrate in a conventional manner using a coater such as a doctor blade, roll coater, comma coater, or gravure coater.
Of the first and second film base materials, the surface of the film base material that will eventually become the base material of the printing blanket is provided with good adhesion between the film base material and the elastomer. A primer layer may be provided.
[0041]
After the elastomer is applied to the surface of the film substrate, the elastomer layer is held horizontally to be cured while smoothing the elastomer layer by self-leveling.
The top surface of the horizontal platform for allowing the film substrate to stand is 1 m in order to sufficiently exhibit the smoothing effect by self-leveling.² It is required to have a very high level of level so that the difference in height per hit is within 0.02 mm. When the level does not satisfy the above range, the intended purpose may not be achieved in smoothing by self-leveling.
[0042]
When the film base material formed by applying and forming the elastomer layer is allowed to stand on a horizontal base, it is preferable that the film base is in close contact with the horizontal base in order to more reliably perform self-leveling.
As a practical adhesion means, for example,
(a) Use static electricity generated between the film base and the horizontal base,
(b) While holding and pulling the edge of the film substrate, press against the horizontal base,
(c) Air is sucked between the film base and the horizontal base.
(d) Sealing the film substrate on a horizontal base and air-pressurizing with the elastomer layer,
And the like.
[0043]
In the case of a room temperature curable elastomer, the elastomer is applied on a film substrate and allowed to stand on a horizontal base, and then left to stand for about 8 to 24 hours to complete curing. In order to accelerate the curing, warm air may be blown against the elastomer, but in this case, care must be taken so that the wind pressure does not adversely affect the smoothing of the elastomer layer.
It is preferable to overlap the elastomer layers in the first and second sheets, for example, through an adjusted guide so that the two sheets are overlapped without causing a shift. By passing the sheet between the pair of rolls, the air remaining on the surfaces of the first and second elastomer layers is expelled by pressure bonding.
[0044]
  [Peeling of film substrate]
  In the method for producing a printing blanket according to the present invention, the film base material to be peeled after the first sheet and the second sheet are pressure-bonded is preferably the first film base material. When the first film substrate and the second film substrate are pressure-bonded, the elastomer layer (first elastomer layer) formed on the first film substrate is hard.ChemicalIn contrast, the elastomer layer (second elastomer layer) formed on the second film substrate is in an uncured state.In stateis there. That is, the first elastomer layer is more cured than the second elastomer layer. Therefore, by peeling the first film substrate and using the first elastomer layer side surface as the ink carrying surface, distortion that may occur when the elastomer layer is pressure-bonded is as much as possible to the printing accuracy of the printing blanket. It is possible to prevent the influence.
[0045]
In the printing blanket manufacturing method according to the present invention, it is preferable that the thickness of the elastomer layer from which the film substrate is peeled is larger than the thickness of the other elastomer layer. Since the surface of the elastomer layer from which the film base material is peeled becomes a surface for receiving and receiving printing ink, it is necessary to design the surface so that the roughness of the surface becomes extremely small. Here, when the thickness of the elastomer layer from which the film substrate is peeled is thicker than the other elastomer layer, compared to the opposite case, from the ink carrying surface of the printing blanket to the joint surface between the elastomer layers The distance becomes longer, and the influence of the distortion that occurs at the time of pressure bonding becomes difficult.
[0046]
【Example】
Next, an Example and a comparative example are given and this invention is demonstrated.
[Manufacture of printing blankets]
Example 1
A liquid silicone rubber [trade name “KE1600” manufactured by Shin-Etsu Chemical Co., Ltd.] was applied onto a polyethylene terephthalate (PET) film having a thickness of 0.2 mm. The coating was performed over 120 cm square so that the thickness was 0.7 mm. After the application, the PET film was placed on a flat place and allowed to stand at room temperature for 24 hours to cure the silicone rubber. In this way, a first sheet provided with a cured silicone rubber layer (first elastomer layer) on a PET film (first film substrate) was obtained.
[0047]
On the other hand, the above-mentioned liquid silicone rubber (KE1600) was applied on a PET film having a thickness of 0.4 mm. The coating was performed over 120 cm square so that the thickness was 0.2 mm. After application, the silicone rubber layer was self-leveled by placing the PET film on a flat place and allowing it to stand at room temperature for 10 minutes. Thus, a second sheet provided with an uncured silicone rubber layer (second elastomer layer) on a PET film (second film substrate) was obtained.
Next, the silicone rubber layer side of each of the first sheet and the second sheet was bonded together, and both were crimped by passing through a crimping roll. Further, after being placed on a flat place and allowed to stand at room temperature for 24 hours, the PET film (first film substrate) on the first elastomer layer side is peeled off from the first elastomer layer, and the silicone blanket is removed. Obtained.
[0048]
(Comparative Example 1)
The above liquid silicone rubber (KE1600) was applied onto a PET film having a thickness of 0.4 mm. The coating was performed over 120 cm square so that the thickness was 0.8 mm. After the application, the PET film was placed on a flat place and allowed to stand at room temperature for 24 hours to cure the silicone rubber. Thus, a silicone blanket provided with a silicone rubber layer on a substrate made of a PET film was obtained.
[0049]
[Physical property evaluation of silicone blanket]
(Thickness accuracy)
About the silicone blanket obtained in Example 1 and Comparative Example 1, the thickness was measured at a total of 36 locations, and thickness variation (difference between the maximum value and the minimum value) was determined.
The variation in the thickness of the silicone blanket is required to be suppressed to 0.08 mm or less in order to achieve precision printing. The variation is preferably 0.05 mm or less, and more preferably 0.02 mm or less, in the above range.
The 0.4 mm thick PET film used in Example 1 and Comparative Example 1 had a thickness variation of 0.01 mm. The PET film having a thickness of 0.2 mm used in Example 1 had a thickness variation of 0.01 mm.
[0050]
(Defect observation)
The surface of the silicone blanket obtained in Example 1 and Comparative Example 1 was visually observed, and the number of defects (surface irregularities, etc.) of 100 μm or more was measured.
The number of defects on the silicone blanket surface depends on the size of the individual defects, but to achieve precision printing, the surface of the blanket 1 m² It is required that the number is suppressed to 1 or less per unit (preferably 0).
[0051]
(Print test)
For the printing test, printing ink in which 100 parts by weight of polyester and 500 parts by weight of nickel powder are dispersed in 40 parts by weight of butyl carbitol acetate, the line width of the recesses is 20 μm, the depth is 10 μm, and the pattern spacing is 200 μm. An intaglio with a certain orthogonal pattern (lattice pattern) was used.
[0052]
The silicone blankets obtained in the examples and comparative examples were each mounted on an intaglio offset printing machine, and an orthogonal pattern was formed on a PET film as a substrate using the above intaglio and printing ink.
Printing is carried out continuously for 5 sheets of PET film, and the printing shape of the pattern formed on the PET film every 5 sheets is printed, and the transferability of the ink from the intaglio to the blanket and from the blanket to the substrate is visually observed. Evaluation was performed according to the criteria.
○: The printing ink was almost completely transferred from the intaglio to the blanket and from the blanket to the substrate.
(Triangle | delta): Transfer of printing ink was not perfect, and the one part remained in the recessed part of an intaglio, or the surface of a blanket.
X: Transfer of printing ink was extremely insufficient.
[0053]
The results are shown in Table 1.
[0054]
[Table 1]

[0055]
As apparent from Table 1, when a silicone elastomer that is liquid or pasty in an uncured state is used and the elastomer layer is formed by bonding and pressure bonding of the first sheet and the second sheet, printing is performed. The number of defects appearing on the surface of the blanket can be extremely reduced (to an extent not observed in the examples). That is, an extremely smooth printing blanket could be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a method for producing a printing blanket according to the present invention.
[Explanation of symbols]
10 Blanket for printing
11 First sheet
12 First film substrate
13 (First) Elastomer Layer
14 Second sheet
15 Second film substrate
16 (Second) elastomer layer
17 Elastomer layer

Claims (5)

A step of applying a silicone et elastomer to form said a first film base, a first sheet consisting of a first elastomeric layer cured state on the first film substrate,
On the second film base, wherein the first film is applied to those applied to the substrate the same silicone et elastomer, the second film base, a second elastomeric layer in an uncured state forming a second sheet consisting of,
A step of crimping the elastomeric layer between the first sheet and the second sheet, and cured to coalesce and said second elastomeric layer and the first elastomeric layer,
A step to cure completely, from coalesced elastomer layer, peeling off one of the first film substrate and the second film substrate,
A method for producing a printing blanket, comprising: The silicone et elastomer, characterized in that a liquid or pasty elastomer method for producing a printing blanket of claim 1, wherein. The silicone et elastomer, characterized in that an elastomer at room temperature curable, according to claim 1 or 2 method for producing a printing blanket according. In the step of forming the first sheet, after the coating cloth silicone et elastomer on a first film substrate, at least the first elastomeric layer until losing fluidity, the first film by standing substrate horizontally, the first, characterized in that curing the elastomer layer, the manufacturing method of the printing blanket according to claim 1. The first film substrate and / or the second film base, characterized in that it is a polyethylene terephthalate film, a manufacturing method of the printing blanket according to any one of claims 1 to 4.

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