JP3409872B2 - Blanket and method for producing color filter using the blanket - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blanket having excellent ink acceptability and transferability, and a method for producing a color filter using the blanket.

[0002]

2. Description of the Related Art Generally, a blanket plays a role of receiving ink from a plate and transferring the ink to a printing material. The characteristics of the blanket have a great influence on the reproducibility of the printed pixel shape and the stability during continuous printing. give. Properties of such a blanket include physical properties of rubber such as wettability to ink and viscoelasticity, which are defined by critical surface tension and the like.

Among these, the critical surface tension of rubber has a great influence on the ink acceptance rate from the plate to the blanket and the ink transfer rate from the blanket to the substrate, and this ink transfer rate substantially controls the suitability for continuous printing. is important.

The critical surface tension of rubber also has a great influence on the shape of printed pixels. In other words, in a blanket with extremely poor critical surface tension, the ink transferred from the plate is repelled on the blanket, which causes the line width to become smaller than the planned line width, or in the case of significant line breaks. . On the other hand, in the case of a blanket with extremely large critical surface tension, the ink transfer rate from the blanket to the work is significantly reduced, and the ink remaining on the blanket makes it extremely difficult to control the film thickness during continuous printing. .

However, it has not hitherto been performed to numerically measure the critical surface tension of the blanket and design the blanket based on it. That is, the conventional blanket design has been performed based on the swelling property of the surface rubber layer with respect to the ink used and the sensible ink transfer property. Therefore, line width reproducibility ± 5 μm, film thickness reproducibility 0.3 μm
The conventional blanket is unsuitable for the ultra-precision printing that prints the pattern of the liquid crystal color filter that requires the precision of.

For example, ethylene propylene rubber (EPD
M), nitrile butadiene rubber (NBR) and the like, when the colored layer (line width of about 100 μm) of the liquid crystal color filter is printed by lithographic offset, the minimum resolution is 30 to
It is as bad as 40 μm, and since EPDM and NBR have high critical surface tension and high ink wettability, the ink transfer rate from the blanket to the glass plate that is the printing target is low (5
0% or less), resulting in ink piling on the blanket. For this reason, when continuous printing was performed, the line width and the printed film thickness increased, and the spectral transmittance tended to decrease, making it unusable.

Further, a colored layer (line width of about 100 to 3) for a liquid crystal color filter is used by using a silicone blanket.
It has been reported that an intaglio offset printing method is used (JP-A-62-85202). Since a silicone blanket generally has a low critical surface tension and a low wettability to ink, the ink transfer rate from the blanket to the glass plate is high, and the stability in continuous printing is increased. At the same time, however, the ink tends to be repelled on the blanket due to the low wettability with the ink, which is necessary to clearly reproduce a pattern with a narrow line width (about 20 μm) like a black matrix layer. It is difficult to obtain high resolution. Also, 100 μm
The line width reproducibility of the colored layer tends to be small.

The thinning of the pixel line width of a printed pixel, which occurs when a rubber having a relatively low critical surface tension such as the above-mentioned silicone rubber, is used as a blanket, and the deterioration of the minimum resolving power due to the breaking of the thin line is mainly caused by the plate. Occurs in the process of receiving ink from the blanket to the blanket.

Ink receptivity including line width reproducibility and fine line reproducibility (from plate to blanket) is considered to be affected by the physical properties of the blanket, especially viscoelasticity, and the critical surface tension of rubber is low, resulting in ink acceptance. It is considered that the effect is more remarkable as the rubber is subjected to the critical condition.

Therefore, the ink transfer rate from the blanket to the work for printing the liquid crystal color filter is required to be high, and the high line width reproducibility of about ± 5 μm and the minimum resolving power of about 10 to 20 μm are required. It is considered necessary to precisely control the physical properties of rubber, especially viscoelasticity, in the ultra-precision printing blanket. However, high-precision viscoelasticity control has not been performed from such a viewpoint, and the effect of rubber viscoelasticity on ink acceptability has not been clarified.

[0011]

As described above, in the conventional blanket design stage, it is not possible to accurately control the physical properties of the blanket by quantifying the critical surface tension and viscoelasticity of the surface rubber layer of the blanket. Therefore, the ink transfer rate from the blanket to the printed material is low and ink printing occurs on the blanket, and continuous printing cannot be performed. Conversely, the ink transfer rate is high and the ink acceptance for the blanket is good. However, there was a problem that the fine lines could not be reproduced clearly because the ink was repelled on the blanket. A printing method using a blanket for ultra-precision printing is regarded as important because it can correspond to the recent reduction in the manufacturing cost required for color filters. A colored layer having a line width of about 100 μm and a black layer having a line width of about 20 μm are used. It is required to be able to clearly reproduce the matrix layer.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a blanket having a high ink transfer rate and fine line reproducibility, and a method for producing a color filter using the blanket. To do.

[0013]

In order to achieve such an object, the present invention comprises a surface rubber layer on the outermost surface, and the surface rubber layer has a surface tension in the range of 10 to 23 dyne / cm . The viscoelasticity tan δ was set to be in the range of 0.05 to 0.25.

Further, according to the present invention, the ink retained on the intaglio plate having a desired pattern of the color filter is transferred to the surface rubber layer of the blanket cylinder using the above blanket, and then transparent from the blanket cylinder. The ink was transferred onto the substrate.

[0015]

The blanket has a surface rubber layer having a critical surface tension in the range of 10 to 23 dyne / cm and a viscoelasticity tan δ of 0.05 to
By setting it in the range of 0.25, the blanket has an ink transfer rate of 100% and very good ink acceptability. Then, a colored layer having a line width of about 100 μm and a line width of 20 μ are formed by intaglio offset printing using a blanket cylinder equipped with such a blanket.
A black matrix layer of about m can be clearly reproduced, and extremely stable continuous printing is possible.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an example of the blanket of the present invention. In FIG. 1, blanket 1 is base cloth 2
And a surface rubber layer 4 formed on the base cloth 2 via a compression layer 3.

The base cloth 2 has a function of preventing the blanket 1 from being stretched due to tension when the blanket 1 is mounted on the blanket cylinder of the printing machine, and the known base cloth used in the conventional blanket is used. Can be used.

The compression layer 3 has a sponge-like structure. When pressure is applied to the surface rubber layer 4 from the outside, the compression layer 3 is compressed and absorbs stress to deform the surface rubber layer 4 (bulge). It prevents the occurrence of (phenomenon) and prevents the reduction of the dimensional accuracy of the printed pattern.

The surface rubber layer 4 has a function of receiving the ink held on the intaglio plate and then transferring the received ink to the material to be printed. The blanket 1 of the present invention is characterized by optimizing the surface chemical properties (critical surface tension) and physical properties (viscoelasticity) of the surface rubber layer 4.

First, the surface rubber layer 4 has a critical surface tension of the surface rubber of 10 to 23 dyne / cm , preferably 15 to 23.
I chose a material that gives dyne / cm . The critical surface tension is 23 dyne /
If it is larger than cm, the wettability of the surface rubber layer 4 to the ink is too high, and the ink transfer rate from the blanket to the printing object becomes low, which causes piling. On the other hand, when the critical surface tension is less than 10 dyne / cm , the ink receptivity from the plate to the blanket is lowered, and the fine line reproducibility and the line width reproducibility are lowered, which is not preferable.

Here, the contact angle between the monomer of the ink resin and the surface rubber layer can be measured as follows. That is, the rubber to be measured is cut to an appropriate size, measured with a contact angle meter CA-D type (manufactured by Kyowa Interface Science Co., Ltd.), and determined from Zisman plot. The solvent used for the Zisman plot and its surface tension are shown below.

Solvent name Surface tension ( dyne / cm 2 ) ・ Ethanol… 20.05 ・ Diethylene glycol monoethyl ether… 31.9 ・ Trimethylolpropane triacrylate… 35.5 ・ Diallyl phthalate… 36.8 Generally the critical surface tension is 10 The rubber material in the range of up to 23 dyne / cm includes dimethyl siloxane, methyl vinyl siloxane, methyl fluorovinyl siloxane, methyl phenyl vinyl siloxane, and the above polymers and NB.
R, EPDM, blends and copolymerization systems with styrene-butadiene rubber (SBR), fluororubber, and NBR, EP
Examples thereof include those obtained by mixing silicone oil or the like into DM, SBR, etc., and those obtained by baking NBR, EPDM, SBR in a siloxane atmosphere at 100 to 200 ° C. for about 1 hour to form a coat layer having a small surface energy.

Next, the viscoelastic characteristics of the material whose critical surface tension is set to a predetermined value as described above are adjusted.
Here, the viscoelasticity (tan δ) of rubber is the rheovibron DD
V-II-EP (Orientec Co., Ltd.), temperature 20
Measured at a temperature of 11 ° C. and a frequency of 11 Hz.

The viscoelasticity of the rubber material depends on the density of cross-linking groups in the raw rubber, the localized state of cross-linking groups, the type of filler, the content rate, the particle size, the surface treatment, the type of cross-linking agent, the primary vulcanization conditions (temperature). , Time, etc.) It can be adjusted by the presence or absence of secondary vulcanization and the conditions thereof.
Here, as the filler to be used, fumed silica, ground silica, precipitated silica, calcium bicarbonate, calcium carbonate, diatomaceous earth, talc, quartz powder and the like can be used.

In the present invention, the viscoelasticity tan δ of the surface rubber layer 4 is
Is in the range of 0.05 to 0.25, preferably 0.10 to
It is set to be in the range of 0.20. When the viscoelasticity tan δ of the surface rubber layer 4 is less than 0.05, the ink acceptability from the plate to the blanket decreases, the image line becomes thin, and the edge accuracy decreases, which is not preferable. On the other hand, if the viscoelasticity tan δ exceeds 0.25, the viscous physical properties of the blanket become too large, which adversely affects pitch accuracy and workpiece chucking, which is not preferable.

The surface rubber layer 4 of the blanket 1 of the present invention as described above is a state in which the surface rubber is applied onto the base cloth 2 and the compression layer 3 and then a film having a smooth surface is pressure-bonded to the surface rubber-coated surface. It is prepared by vulcanizing at 1, then peeling off the film. Also, a rubber sheet produced by vulcanizing a film having a smooth surface under pressure is laminated on the compression layer 3 so that the surface from which the film having a smooth surface is peeled is the outermost surface. You may.
As the film having a smooth surface, a polyethylene terephthalate (PET) film, a polyethylene (PE) film and the like are preferable.

The surface rubber layer 4 may be formed on the compression layer 3 via an anchor layer. In this case, the anchor layer can be formed of a material such as a cotton cloth layer or a silane coupler agent. The thickness of this anchor layer is 0-5
It is preferably about 00 μm.

Further, in the above-mentioned example, the blanket 1 is a so-called compressible type blanket, but the present invention is not limited to this and may be a solid type blanket having no compression layer.

Then, by using the blanket cylinder equipped with the blanket 1 of the present invention as described above, a high resolution color filter can be continuously printed by intaglio offset printing. FIG. 2 is a diagram illustrating formation of a fine pattern in manufacturing a color filter using the blanket of the present invention. In FIG. 2, first, the ink 12 is filled into the recesses 11 formed in the intaglio 10 in a predetermined pattern (FIG. 2A). Next, the blanket cylinder 15 equipped with the blanket 1 of the present invention is pressed onto the intaglio plate 11 while being rotationally moved to transfer the ink 12 in the recess 11 onto the blanket cylinder 15 (FIG. 2B). Then, the blanket cylinder 15 is attached to the transparent glass substrate 2 which is the object to be printed.
The ink 12 on the blanket cylinder 15 is transferred to the transparent glass substrate 20 by pressure-bonding to 0 to form a fine pattern (FIG. 2C).

The plate depth of the intaglio plate in such intaglio offset printing is preferably 8 μm or less, more preferably 3 to 8 μm. Next, the present invention will be described in more detail with reference to experimental examples.

Experimental Example 1 (Preparation of blanket sample) A surface rubber was applied on a base material composed of a base cloth and a compression layer, and then vulcanization was performed while the PET film was pressed onto the surface rubber-coated cotton. The film was peeled off to form a surface rubber layer (thickness: about 100 μm) to prepare blankets (Samples 1 to 16). The conditions for producing each blanket (Samples 1 to 16) were as follows, and the critical surface tension, surface roughness, viscoelasticity, and hardness of each sample rubber were as shown in Table 1 below. At this time, as a preferable range of the surface roughness and hardness of the rubber, the surface roughness Ra was 1.0 μ or less and the hardness was 50 to 80 °.

[0032]

[Table 1] In each of the blankets of Samples 1 to 5, the critical surface tension of the surface rubber layer was changed.

Sample 1: The critical surface tension was 10 dyne / cm . The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) KE765-U manufactured by Shin-Etsu Silicone Co., Ltd. 100 parts by weight Cross-linking agent 2,5-di-methyl-2,5-di-t-butylferroxyhexane 5 parts by weight (vulcanization conditions) Primary Vulcanization 170 ° C, 20 minutes Secondary vulcanization 200 ° C, 4 hours * Atmosphere during secondary vulcanization was retained. The atmospheric conditions during the secondary vulcanization have a great influence on the critical surface tension of the blanket surface. It is considered that this is because the low-molecular-weight siloxane in the dispersed rubber during the secondary vulcanization redeposits on the surface, so that the secondary surface vulcanization under the conditions of residence in the atmosphere lowers the critical surface tension of the rubber.

Sample 2: The critical surface tension was 18 dyne / cm . The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) KE765-U manufactured by Shin-Etsu Silicone Co., Ltd .... 100 parts by weight Crosslinking agent 2,5-di-methyl-2,5-di-t-butylferroxyhexane ... 5 parts by weight (vulcanization condition) Primary Vulcanization 170 ° C., 20 minutes Secondary vulcanization 200 ° C., 4 hours * Fresh air was introduced during secondary vulcanization.

Sample 3: The critical surface tension was 23 dyne / cm . The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) KE5570-U manufactured by Shin-Etsu Silicone Co., Ltd. 100 parts by weight Crosslinking agent 2,5-di-methyl-2,5-di-t-butylferroxyhexane 5 parts by weight (vulcanization conditions) Primary Vulcanization 170 ° C., 20 minutes Secondary vulcanization 200 ° C., 4 hours * Fresh air was introduced during secondary vulcanization.

Sample 4: The critical surface tension was 8 dyne / cm . The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) KE765-U manufactured by Shin-Etsu Silicone Co., Ltd .... 100 parts by weight Crosslinking agent 2,5-di-methyl-2,5-di-t-butylferroxyhexane ... 5 parts by weight (vulcanization condition) Primary Vulcanization 170 ° C, 20 minutes Secondary vulcanization 200 ° C, 4 hours * Secondary vulcanization atmosphere was retained. Further, the dimethyl silicone oil was heated in the chamber used for the secondary vulcanization to forcibly form a redeposition coating film of low molecular weight siloxane on the rubber surface.

Sample 5: The critical surface tension was set to 25 dyne / cm . The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) KE5570-U manufactured by Shin-Etsu Silicone Co., Ltd. 100 parts by weight JSR N220SH manufactured by Nippon Synthetic Rubber Co., Ltd. 10 parts by weight Crosslinking agent 2,5-di-methyl-2,5-di-t-butylferro Xyhexane: 5 parts by weight Sulfur yellow: 0.3 parts by weight Thallium: 0.1 parts by weight (vulcanization conditions) Primary vulcanization 170 ° C., 20 minutes Secondary vulcanization 200 ° C., 4 hours The critical surface tension is The following solvents were used, the contact angle was measured by CA-D model, Kyowa Interface Science Co., Ltd., and calculated from Zisman plot.

Solvent Name Surface Tension (dyne / cm) -Ethanol 20.05-Diethylene glycol monoethyl ether 31.9-Trimethylolpropane triacrylate 35.5-Diallyl phthalate 36.8 Each blanket of Samples 6 to 9 has a surface. The surface roughness of the rubber layer was changed. That is, in the blankets of Samples 6 to 9, a base layer (including a compression layer) was coated with a rubber layer, and the PE layer having an arbitrary surface roughness was coated on the rubber layer.
After T was pressure-bonded, primary vulcanization was performed to crosslink the rubber, and then the PET film was peeled off from the rubber surface to form a blanket rubber surface having an arbitrary surface roughness.

The surface roughness Ra was confirmed by a Deck Tuck 16000, ULVAC, Inc., with a needle pressure of 5 mmg and a measuring range of 1 m.
m and the measurement speed was low, and Ra was calculated. In each of the blankets of Samples 10 to 13, the viscoelasticity of the surface rubber layer was changed.

Sample 10: Viscoelasticity tan δ was set to 0.05. The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) Shin-Etsu Silicone KE-108 ... 100 parts by weight Curing agent CAT-108 (Shin-Etsu) ... 5 parts by weight Filler CERATOM FW-14 (Kakiuchi Co., Ltd.) ... 30 parts by weight (vulcanization conditions) Primary vulcanization 25 ° C, 75 hours * No secondary vulcanization Sample 11: Viscoelasticity tan δ was set to 0.25. The composition for forming the surface rubber layer and the vulcanization conditions used were as follows.

(Composition) Toray Silicone Co., Ltd. SH 746U… 100 parts by weight Crosslinking agent RC-4 (Toray Silicone)… 0.5 parts by weight (vulcanization conditions) Primary vulcanization 170 ° C., 1 hour * Secondary Unvulcanized Sample 12: Viscoelasticity tan δ was set to 0.01. The composition for forming the surface rubber layer and the vulcanization conditions used were as follows.

(Composition) KE-108 Shin-Etsu Silicone Co., Ltd. 100 parts by weight Curing agent CAT-108 (Shin-Etsu) 5 parts by weight Filler Aerosil 200 (Japan Aerosil Co., Ltd.) 15 parts by weight (vulcanization conditions) ) 25 ° C, 75 hours * No secondary vulcanization Sample 13: Viscoelasticity tan δ was 0.3. The composition for forming the surface rubber layer and the vulcanization conditions used were as follows.

[0043]   (Composition)       Shin-Etsu Silicone Co., Ltd. FE361-U… 100 parts by weight       Crosslinking agent C-8A ... 5 parts by weight (Vulcanization conditions) Primary vulcanization 165 ° C, 10 minutes Secondary vulcanization 200 ℃, 4 hours * The atmosphere was retained.

The viscoelasticity tan δ was measured at 20 ° C. with Rheovibron DDV-II-EP manufactured by Orientec Co., Ltd.
It was measured at a frequency of 11 Hz. In each of the blankets of Samples 14 to 16, the hardness of the surface rubber layer was changed.

Sample 14: Hardness was 50 °. The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) Shin-Etsu Silicone KE742U ... 100 parts by weight Crosslinking agent 2,5-di-methyl-2,5-di-t-butylferroxyhexane ... 5 parts by weight (vulcanization conditions) Primary vulcanization 170 ° C., 20 Minute * No secondary vulcanization Sample 15: Hardness was set to 80 °. The composition for forming the surface rubber layer and the vulcanization conditions used were as follows.

(Composition)         Shin-Etsu Silicone Co., Ltd. KE785-U… 100 parts by weight         Cross-linking agent 2,5-di-methyl-2,5-di-t-butylferroxyhexane                                                       … 5 parts by weight (Vulcanization conditions) Primary vulcanization 170 ℃, 20 minutes Secondary vulcanization 200 ℃, 4 hours * Fresh air was introduced during the secondary vulcanization.

Sample 16: Hardness was 40 °. The composition for forming the surface rubber layer and the vulcanization conditions used were as follows. (Composition) KE742-U Shin-Etsu Silicone Co., Ltd. 100 parts by weight Cross-linking agent 2,5-di-methyl-2,5-di-t-butylferroxyhexane 5 parts by weight (vulcanization conditions) Primary addition Sulfuric acid 170 ° C, 20 minutes * No secondary vulcanization (evaluation of blanket sample) Using the blanket samples 1 to 16 prepared as described above, intaglio plates having different line & space (L & S) patterns (plate depth 6 μm) The pattern was printed on a glass substrate and the resolution in L & S was measured. In addition, the ink transfer rate from the blanket to the glass substrate was measured. The composition of the ink used for the measurement is shown below. (Ink composition) Pigment anthraquinone type lett 16% by weight Disazo type yellow 4% by weight Resin oligoester acrylate 42% by weight Diallyl phthalate prepolymer 18% by weight Monomer diallyl phthalate monomer 15% by weight Solvent agent Diethylene glycol monoethyl ether 5% by weight The ink transfer rate was measured as follows. First, for the ink transfer film from the plate to the blanket, a microscopic photograph was taken on the blanket using an interference film thickness meter Sin 20X (Union Optical Co., Ltd.), and the ink film thickness was measured from the photograph. This is defined as the film thickness from the plate to the blanket = a (μm).

Next, printing on glass is performed under the same conditions,
The ink film thickness on the glass is similarly measured. Ink film thickness transferred from blanket to glass = b
(Μm).

By the above, Ink transfer rate = b / a x 100 (%) Ask for.

As shown in Table 1, Samples 1 to 3, 6 to 8, 10, 11, 14, 1 which are blankets of the present invention.
When No. 5 was used, the ink transfer rate from the blanket cylinder to the glass substrate was high (100%), and the resolution in L & S was 20 μm, and good results were obtained. On the other hand, when other blankets were used, none of them had a good ink transfer rate and a good resolution in L & S.

Experimental Example 2 Using the blanket of Sample 2 of Experimental Example 1 above, 120
Intaglio offset printing on a glass substrate was continuously performed using an intaglio (plate depth 5 μm) having a stripe pattern of μm. As a result, as shown in FIG. 3, when the blanket of the present invention, Sample 2, was used, the ink transfer rate from the blanket to the glass substrate was high (100%), so that the line width was slightly (about 3 μm). Although it became thinner, continuous printing was possible with a stable line width. However, when Sample 5 was used, the ink transfer rate was low (80%), so that the line width drastically increased, exceeding the range of use for color filters.

[0052]

As described in detail above, according to the present invention, by controlling the critical surface tension and viscoelasticity of the surface rubber layer, a blanket having a high ink transfer rate of 100% and a high resolution can be obtained. Further, it is possible to manufacture a color filter having a high fine line accuracy by using the blanket by a printing method, and further, it is possible to obtain an effect that the line width and the ink film thickness during continuous printing are stable.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a blanket of the present invention.

FIG. 2 is a diagram illustrating formation of a fine pattern in manufacturing a color filter using the blanket of the present invention.

FIG. 3 is a diagram showing a change in line width when intaglio offset printing is continuously performed.

[Explanation of symbols]

1 ... Blanket 2 ... Base cloth 3 ... compression layer 4 ... Surface rubber layer 10 ... Intaglio 15 ... Blanket body 20 ... Glass substrate

Claims (3)

(57) [Claims] 1. A surface rubber layer is provided on the outermost surface, and the surface rubber layer has a critical surface tension in the range of 10 to 23 dyne / cm and a viscoelasticity tan δ in the range of 0.05 to 0.25. A blanket , wherein the surface rubber layer is formed by applying a surface rubber on a base fabric,
A state where a film with a smooth surface is crimped onto the surface coated with rubber
It is prepared by vulcanizing with, and then peeling off the film.
A blanket that has been characterized. 2. A surface rubber layer is provided on the outermost surface, and the surface rubber is provided.
The layer has a critical surface tension in the range of 10-23 dyne / cm.
The viscoelasticity tan δ is in the range of 0.05 to 0.25.
A blanket, wherein the surface rubber layer is formed by pressing a film having a smooth surface.
Laminated vulcanized rubber sheet on base fabric
A blanket characterized by being created by. 3. The surface rubber layer has a compression layer on a base cloth.
Claim 1 or Claim characterized by being formed by
The blanket according to item 2.