JP2013240907A - Blanket for offset printing, method of processing blanket and method of manufacturing blanket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blanket that has superior reception performance of ink and transferability to a printed matter, and has no winding up of the printed matter.SOLUTION: An offset printing blanket has a surface layer including silicon rubber. The surface layer is partially coated with silicon dioxide (SiO), and has a tack value by a probe tack test regulated by JISZ0237 of 200gf or less, and a tack value with respect to a mending tape of 250gf or more.

Description

  The present invention relates to a blanket for offset printing, a method for processing the blanket, and a method for manufacturing the blanket. More specifically, the present invention relates to a blanket for offset printing mounted on an offset printing machine, a method for processing the blanket, and a method for manufacturing the blanket.

  The offset printing is a method of printing by transferring the ink attached to the image portion of the plate cylinder to the surface of the blanket (surface rubber layer) and then transferring it to the substrate by an offset printing machine.

  FIG. 1 is a diagram for explaining a formation state of a fine pattern when a thick film is formed using a blanket, which is also applied to an embodiment of the present invention described later by offset printing using an intaglio. Thus, offset printing using an intaglio is performed as follows, for example. That is, in FIG. 1, first, the ink 12a is filled with the blade 20 into the recess 11 formed in a predetermined pattern on the intaglio 10 (see FIG. 1A). Next, the blanket cylinder 13 to which the blanket of the present invention is attached is pressed on the intaglio plate 10 while being rotationally moved to transfer the ink 12a in the recess 11 onto the blanket cylinder 13 (see FIG. 1B). Subsequently, the blanket cylinder 13 is pressure-bonded to the substrate 14 to transfer the ink 12a on the blanket cylinder 13 to the substrate 14 to form a fine pattern (see FIG. 1C).

  Recently, such an offset printing method has been used for printing such as touch panel electrode printing and conductive ink printing on a green sheet formed on a release film in the printed electronics field ( For example, see Patent Document 1).

  As a blanket used for such offset printing, a silicone rubber blanket having a surface layer made of silicone rubber is used particularly from the viewpoint of good solvent absorbability and releasability.

JP 2008-49495 A

  However, since such a silicone rubber blanket has a mirror-like surface and has high adhesion to the ink (tack value), the problem of winding up the substrate to be printed often occurs in the printing process. On the other hand, if the adhesiveness of the blanket surface is reduced, for example, by roughening the surface by polishing or the like, the ink acceptability is lowered. As a result, it becomes difficult to obtain a uniform film thickness (ink thickness) for the ink on the surface of the substrate.

  The present invention has been made in view of the above-described circumstances, and has both good ink acceptability and good transferability to a printing material, and does not cause the printing material to be rolled up, a method for processing the blanket, and It aims at providing the manufacturing method of this blanket.

  The blanket for offset printing according to the first aspect of the present invention is a blanket for offset printing having a surface layer containing silicone rubber, and the surface layer is partially covered with silicon dioxide. In addition, the tack value according to the probe tack test defined in JISZ0237 is 200 gf or less, and the tack value for the mending tape is 250 gf or more.

  A processing method of an offset printing blanket according to a second aspect of the present invention is a processing method of an offset printing blanket having a surface layer containing silicone rubber, wherein the surface is exposed to a flame and subjected to heat treatment. By covering at least part of the surface of the layer with silicon dioxide, the tack value by the probe tack test specified in JISZ0237 is 200 gf or less, and the tack value for the mending tape is 250 gf or more. .

A processing method of an offset printing blanket according to a third aspect of the present invention is a processing method of an offset printing blanket having a surface layer containing silicone rubber, and is subjected to heat treatment by exposure to a flame containing a silane compound as a vapor. By performing at least a part of the surface of the surface layer with silicon dioxide,
The tack value by the probe tack test specified by Z0237 is 200 gf or less, and the tack value for the mending tape is 250 gf or more.

  In the flame, the ratio of propane gas: air: Itrogas (registered trademark) is preferably in the range of 2-10: 130-180: 0-10.

  The distance between the burner that emits the flame and the blanket is preferably 20 to 100 mm, and the burner speed is preferably 20 to 60 m / min.

  The manufacturing method of the offset printing blanket according to the fourth aspect of the present invention includes the processing method of the offset printing blanket according to the second to third aspects of the present invention.

  According to the present invention, it is possible to provide a blanket for offset printing that has both good ink acceptability and good transferability to a printing material, and does not wind up the printing material.

(A)-(c) is a schematic diagram explaining the state by which ink is transcribe | transferred from an intaglio (plate copper) to a blanket, (a) is filling of ink, (b) is acceptance of ink, (c) Indicates ink transfer. It is sectional drawing which shows an example of the laminated constitution of the blanket which concerns on embodiment of this invention. It is explanatory drawing explaining the state in which ink is received to a blanket from an intaglio, and the state by which ink is transcribe | transferred to to-be-printed material. It is a three-dimensional analysis image by the scanning probe microscope (ScanningProbe Microscopy; SPM) about the surface layer of the blanket of the comparative example 2 (unprocessed goods). It is a three-dimensional analysis image by the scanning probe microscope about the surface layer of the blanket of Example 3 (frame processing goods). It is a three-dimensional analysis image by the scanning probe microscope about the surface layer of the blanket of Example 1 (itro process goods). (B) shows the surface photograph of the to-be-printed material which was printed with the blanket of Example 1, and shows the transfer state of the ink in which both the acceptability and transferability of ink were favorable, (a) is the blanket of Comparative Example 2 The surface photograph of the to-be-printed material which shows the transcription | transfer state of the ink printed by (2) which shows the transfer property of the ink which is good, but acceptability is bad is shown.

  When performing surface treatment of a blanket made of silicone rubber, the inventors of the present invention are exposed to a flame containing a silane compound as a vapor and subjected to heat treatment under a predetermined condition, whereby one surface of the silicone rubber layer (surface layer) is treated. Since the part is coated with silicon dioxide and predetermined physical property values are obtained, the above-mentioned problems are solved, the ink acceptability and the transferability to the printing material are both good, and the printing material Led to the development of a blanket that does not wind up.

  Hereinafter, a blanket for offset printing, a blanket processing method, and a blanket manufacturing method including the blanket processing method according to an embodiment of the present invention will be described with reference to the drawings.

<Embodiment>
The blanket for offset printing according to the present embodiment improves the ink acceptability in the blanket by controlling the coating state of silicon dioxide (SiO ₂ ) on the surface of the blanket made of silicone rubber according to the processing conditions. On the other hand, there is a feature in that a characteristic capable of reducing the adherence of the printed material during printing is obtained while ensuring good transferability.

In addition, the processing method and the manufacturing method of the offset printing blanket according to the present embodiment are a processing method of the offset printing blanket having a surface layer made of silicone rubber, and the flame includes the surface layer of the blanket as a vapor of a silane compound. The surface of the surface layer is covered with silicon dioxide under the predetermined conditions as described below. And JIS
By setting the tack value in the probe tack test specified by Z0237 to 200 gf or less and the tack value for the mending tape to 250 gf or more, the above-mentioned problems are solved.

In the following description, “Itrogas” means, for example, an air mixed compressed gas containing 1.0 × 10 ⁻⁴ mol% tetramethylsilane and 1.0 × 10 ⁻⁵ mol% tetramethoxysilane as a surface modifier. Can be used. Here, the mol% of tetramethylsilane and tetramethoxysilane is the total amount of itrogas of 100 mol%. In addition, itrogas other than this composition can also be used.

In addition, in the surface treatment (itro treatment) using this “Itorogas”, a chemical reaction represented by the following formula 1 occurs.
Silane compound (organosilicon: Si—O) + O ₂ (oxygen, air) + LPG (liquefied petroleum gas) => SiO ₂ + H ₂ O (water vapor) + CO ₂ (carbon dioxide) (Formula 1)

The “tack value by the probe tack test” is defined by JIS Z0237, and is measured by the following method.
That is, a test piece (width = about 25 mm, length = about 25 mm) is attached to a probe tack test device, the probe is brought into contact with the silicone rubber layer for a certain period of time while applying a certain load, and then the probe is perpendicular to the silicone rubber layer. The force required for peeling in the direction is obtained, and this is used as the probe tack value. Here, a stainless steel SUS cylindrical probe (diameter = 5 mm) is used as the probe, the contact speed (peeling speed) is 10 mm per second, the contact load is 0.98 N / cm ² , and the contact time is 1 second.

The “tack value with respect to the mending tape” is measured by the following method using a product name (model number): mending tape CM15-DC manufactured by Sumitomo 3M as the mending tape.
That is, a test piece (width = about 25 mm, length = about 25 mm) is attached to a probe tack test device, the above-mentioned mending tape is brought into contact with the silicone rubber layer for a certain period of time while applying a certain load, and then the probe is silicone rubber. The force required to peel off from the layer in the vertical direction is determined, and this is used as the probe tack value. Here, the contact speed (peeling speed) is 10 mm per second, the contact load is 0.98 N / cm ² , and the contact time is 1 second.

(Blanket processing method)
As the silicone rubber to be subjected to the surface treatment according to the present embodiment, for example, a peroxide-crosslinked silicone rubber or an addition-crosslinked silicone rubber can be used.

  Moreover, as a silane compound included as a vapor | steam in a flame, tetramethylsilane, tetramethoxysilane, and mixtures thereof can be used, for example.

  Further, the heat treatment can be performed only with a flame (frame) without using a gas. In addition, when using itrogas containing a silane compound with a flame, use a flame in which the ratio of propane gas: air: itrogas (registered trademark) is in the range of 2-10: 130-180: 0-10. Is preferred. This is because if the upper limit of this range is exceeded, deposits such as silica may be formed in layers.

  Further, it is preferable that the distance between the burner for releasing the flame and the silicone rubber blanket is 20 to 100 mm and the burner speed is 20 to 60 m / min. If the lower limit of this range is exceeded, combustion may occur. If the upper limit is exceeded, the heat treatment becomes insufficient, and the desired surface processing may not be realized.

  Moreover, it is preferable that the coating state of silicon dioxide on the surface of the silicone rubber layer (surface layer) partially covers the surface of the silicone rubber layer. Specifically, it is preferable that silicon dioxide is scattered on the surface of the silicone rubber layer and partially covered. For example, a surface state as shown in FIG. 4B (Example 3) and FIG. 4C (Example 1) is desirable. As a comparison, FIG. 4A (Comparative Example 2) shows the surface state of the silicone rubber layer before the surface treatment.

(Blanket manufacturing method)
With reference to FIG. 2, the manufacturing method of the blanket in this embodiment is shown. In this embodiment, the silicone rubber blanket 12 as a base has a two-layer structure in which a silicone rubber layer 32 is laminated on a base material 34 made of PET or the like. The silicone rubber blanket 12 having such a configuration can be manufactured, for example, as follows.

First, an addition-crosslinking type silicone rubber is formed on the surface of a base material 34 made of a resin film selected from the group consisting of a PET film, a PPS film, a PEN film, etc., and then both are vulcanized and bonded to form a silicone rubber blanket. 12 is obtained.
Here, the uncrosslinked silicone rubber formed on the surface of the substrate 34 may be a peroxide-crosslinked silicone rubber or an addition-crosslinked silicone rubber.

  By performing the surface treatment as shown in the above (Blanket processing method) on the silicone rubber blanket 12 obtained by the above manufacturing method, as shown in FIG. Since the surface tension of the silicone rubber blanket 12 is small when the ink 12a is transferred to the substrate 22 after being received, a good transfer state without ink separation is realized. On the other hand, as shown in FIG. 3, when the blanket processing method according to the present embodiment is not performed and the surface tension of the silicone rubber blanket 12 is large, the ink is divided and the transfer state becomes poor.

  Hereinafter, the present invention will be described more specifically with reference to examples. Needless to say, the technical scope of the present invention is not limited to the embodiments described below. Hereinafter, description will be made with reference to FIGS. 1 and 2 as appropriate.

[Example]
<Example 1>
First, a main agent composed of a linear vinyl group-containing dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KE-1935-A) blocked at both ends with dimethylvinylsiloxy groups, and methyl having a branched structure A curing agent made of hydrogen polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KE-1934-B) was prepared.
Subsequently, these main agent and curing agent were mixed at a ratio in which the number of moles of vinyl groups in the main agent and the number of moles of SiH groups in the curing agent were equal.

Subsequently, a platinum group metal catalyst was added to the obtained mixed solution and dissolved in toluene to prepare an addition-crosslinking type silicone rubber composition.
Subsequently, the obtained silicone rubber composition was formed on the surface of a PET (Polyethylene telephtalate) film having a thickness of 125 μm and a surface roughness (Ra) of 0.5 μm.

  Subsequently, the silicone rubber composition was subjected to addition crosslinking at 140 ° C. for 3 minutes. Thereby, the silicone rubber blanket 12 in which the addition-crosslinked silicone rubber layer (surface layer having a thickness of 350 μm) 32 was formed on the resin film (base material) 34 made of the PET was obtained.

  With respect to the silicone rubber layer 32 of the silicone rubber blanket 12 obtained by the above-described method, a silane compound (here, tetramethylsilane and tetramethoxy) is used with a silicate flame treatment apparatus (manufactured by Itro Co., Ltd., model number: ITS-1). A blanket 12 of this example was produced by surface treatment with a flame of fuel gas containing a silane mixture (included in itrogas) as a vapor) (see FIG. 4C).

  The surface treatment conditions here (hereinafter referred to as “treatment conditions”) are propane gas: air: itrogas mixing ratio of 6: 160: 1, and the distance from the surface of the silicone rubber that is the object to be treated: 20˜. 40 mm, the burner speed was 30 m / min, and the number of treatments was twice.

<Example 2>
For the silicone rubber layer 32 of the silicone rubber blanket 12 used in Example 1, the surface treatment was performed in the same manner as in Example 1 except that the treatment condition was changed to only one treatment, so that the silicone rubber blanket of Example 2 was used. 12 was produced.

<Example 3>
By subjecting the silicone rubber layer 32 of the silicone rubber blanket 12 used in Example 1 to surface treatment in the same manner as in Example 2 except that the treatment conditions were set to only flame (frame) treatment without using itrogas. A silicone rubber blanket 12 of Example 3 was produced (see FIG. 4B).

<Example 4>
For the silicone rubber layer 32 of the silicone rubber blanket 12 used in Example 1, the surface treatment was performed in the same manner as in Example 3 except that the treatment condition was set at a separation distance of 100 mm from the surface of the silicone rubber as the object to be treated. By performing, the silicone rubber blanket 12 of Example 4 was produced.

<Comparative Examples 1 and 2>
For the silicone rubber layer 32 of the silicone rubber blanket 12 used in Example 1, the surface treatment was performed in the same manner as in Example 3 except that the treatment condition was set to a separation distance of 120 mm from the surface of the silicone rubber as the object to be treated. By performing, the silicone rubber blanket 12 of the comparative example 1 was produced. Moreover, the thing which did not perform the said surface treatment was made into the comparative example 2 (refer FIG. 4A).

[Tack value by probe tack test]
About the silicone rubber blanket 12 produced in Examples 1-4 and Comparative Examples 1 and 2, the probe tack value of the silicone rubber layer (surface layer) 32 was measured. Probe tack value is JIS
Measurement was performed based on the probe tack test method of Z0237.

The test condition was that a test piece (width = about 25 mm, length = about 25 mm) was attached to a probe tack test apparatus, and the silicone rubber layer 32 of the silicone rubber blanket prepared in Examples 1 to 4 and Comparative Examples 1 and 2 was probed. Was applied for a certain period of time while applying a constant load, and then the force required to peel the probe from the silicone rubber layer 32 in the vertical direction was determined and used as the probe tack value. Here, a cylindrical probe made of stainless steel (diameter = 5 mm) was used as the probe, the contact speed (peeling speed) was 10 mm per second, the contact load was 0.98 N / cm ² , and the contact time was 1 second.

[Tack value for mending tape]
Next, silicone rubber was used in the same manner as the “tack value by probe tack test” except that the adhesive part of a mending tape (manufactured by Sumitomo 3M, trade name (model number): mending tape CM15-DC) was used as a probe. The tack value of the silicone rubber layer 32 of the blanket 12 was measured.

[Evaluation of ink acceptability, transferability, and paper releasability]
The silicone rubber blanket 12 obtained in Examples 1 to 4 and Comparative Examples 1 and 2 was evaluated for ink acceptability, transferability, and roll-up property of the printing material. The ink used was prepared by mixing a polyester resin, butyl carbitol acetate (BCA) as a solvent, and silver powder. In addition, a green sheet (a film obtained by forming a dielectric such as alumina on a release film) was used as the substrate. The transfer speed was 50 mm / second.

The obtained results are summarized in Table 1 below.

  Here, with regard to ink acceptability, very good (）) means a state in which there is no image defect due to poor acceptability of ink on the printing material 14, and good (（) means poor ink acceptability. Although the image defect due to the ink was recognized, the acceptability of the ink was in a state that was practically acceptable, and the defect (x) was that the substrate 14 could not accept the ink at all. State.

  The ink transferability was generally good (◯) for all Examples 1 to 4 and Comparative Examples 1 and 2. That is, the transfer property of the ink from the intaglio 10 (plate copper) to the silicone rubber blanket 12 was almost completely performed. However, there was a tendency that the transferability of the ink gradually deteriorated as the transfer from Comparative Example 2 to Example 1 progressed.

  Further, the roll-up property of the printing material tended to become poor as the ink acceptability deteriorated. This roll-up of the printing material is caused by high adhesion with the printing material originally provided in the silicone blanket.

  From the above results, it was confirmed that when the tack value by the probe tack test was 200 gf or less, the roll-up of the blanket substrate was eliminated. Moreover, when the tack value with respect to the mending tape was 250 gf or more, preferably 400 gf or more, it was confirmed that the ink acceptability and transferability were compatible at a high level.

[Reference Experiment 1]
For Example 1 (itro-treated product) and Comparative Example 2 (untreated product), butyl carbitol acetate (hereinafter referred to as “BCA”) widely used as a paste on the obtained silicone rubber layer (surface layer) 32. Was used to measure the static contact angle. As the solvent, butyl carbitol acetate (hereinafter abbreviated as “BCA”) generally used for pastes was used.

The obtained results are summarized in Table 2 below.

  From the above results, it can be seen that in Example 1, the adhesion to BCA has been dramatically improved. This confirmed that the acceptability of blanket ink was greatly improved.

[Reference Experiment 2]
A predetermined image line was printed on a glass substrate using the silicone rubber blanket 12 used in Example 1 and Comparative Example 2. Here, a silver paste is used as the ink, and for the image pattern, the printing plate design values are a stripe pattern with a line width of 75 μm, a line width of 100 μm, and a pad pattern, respectively, and the ink transfer state on the print substrate of the print substrate. Judged the quality. Furthermore, the presence or absence of pinhole defects in the image line was examined.

  FIG. 5B shows the transfer state (image pattern) of the ink on the substrate for Example 1, and FIG. 5A shows the transfer state (image line) of the ink on the substrate for Comparative Example 2. Pattern).

  As shown in FIG. 5B, for Example 1 (itro-processed product), a good line shape (stripe pattern and pad pattern) was obtained, and no occurrence of pinholes was observed. On the other hand, as shown in FIG. 5 (a), in Comparative Example 2 (untreated product), the occurrence of pinholes and the like were slightly observed together with a slightly poor image line shape (stripe pattern and pad pattern).

  Further, in Reference Experiment 2, in Comparative Example 2 (untreated product), the printing material was wound up during printing, but in Example 1, the printing material was not rolled up.

10 Intaglio 11 Recess 12 Silicone Rubber Blanket (Blanket)
12a Ink 13 Blanket cylinder 14 Printed material 20 Blade 32 Silicone rubber layer 34 Base material

Claims (6)

  A blanket for offset printing having a surface layer containing silicone rubber, wherein the surface layer is partially coated with silicon dioxide and has a tack value of 200 gf by a probe tack test defined in JISZ0237. A blanket for offset printing, characterized in that the tack value with respect to the mending tape is 250 gf or more.   A method for processing a blanket for offset printing having a surface layer containing silicone rubber, wherein at least a part of the surface of the surface layer is coated with silicon dioxide by performing heat treatment by exposure to a flame, according to JISZ0237. A method for processing a blanket for offset printing, characterized in that a tack value by a specified probe tack test is 200 gf or less and a tack value for a mending tape is 250 gf or more.   A processing method of a blanket for offset printing having a surface layer containing silicone rubber, wherein at least a part of the surface layer is coated with silicon dioxide by performing heat treatment by exposing it to a flame containing a silane compound as a vapor. By doing so, the tack value by the probe tack test specified by JISZ0237 is set to 200 gf or less, and the tack value for the mending tape is set to 250 gf or more.   4. The blanket for offset printing according to claim 3, wherein the ratio of propane gas: air: Itrogas (registered trademark) in the flame is in the range of 2-10: 130-180: 0-10. Method.   5. The offset printing according to claim 2, wherein a separation distance between the burner that emits the flame and the blanket is 20 to 100 mm, and a burner speed is 20 to 60 m / min. Blanket processing method.   A method for manufacturing a blanket for offset printing, comprising the processing method for a blanket for offset printing according to any one of claims 2 to 5.