JPH0780295B2 - Offset blanket for printing - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates to a printing offset Bed <br/>Ranke' preparative suitable for printing of fine pattern such as a liquid crystal color filter.

[0002]

Conventionally, intaglio offset printing and flat plate offset printing have been suitable for printing fine patterns. For example, three primary colors of red, green, and blue are striped on a glass substrate. It is also used when manufacturing color filters for liquid crystal color televisions arranged in a mosaic pattern.

In such offset printing, it is required to print a pattern accurately and without any defects. For that purpose, when the ink on the plate is transferred onto the offset blanket and then transferred to the glass substrate or the like, it is necessary that the ink on the blanket is transferred almost completely to the glass substrate or the like. In order to transfer the ink almost completely, it is necessary to use a material having a small surface tension, that is, a material that does not easily wet the ink, for the surface printing layer (surface rubber) of the offset blanket. Generally, there are the following methods for reducing the surface tension of a polymer. (a) Use polymers with low surface tension such as fluororubber and silicone rubber. (b) Coating with a polymer having a low surface tension such as fluororubber or silicone rubber. (c) A polymer such as fluororubber or silicone rubber having a low surface tension is blended during molding. (d) At the time of molding, a substance such as tetrafluoroethylene resin having a small surface tension is added.

By the way, if the surface tension is small, the transferability of the ink is improved, but if it is too small, the ink will not be transferred from the plate to the offset blanket. Therefore, in order to perform precision printing, it is necessary to use a blanket having an optimum surface tension for the equipment used for printing and printing conditions. For that purpose, the surface tension of the polymer must be finely controlled, but if the physical properties other than the surface tension of the polymer (normal physical properties, swelling, etc.) also change due to the control of the surface tension, the printing conditions will change, As a result, the optimum value of the surface tension also changes.

That is, in the above method (a), since the polymer itself constituting the surface printing layer is changed, other physical properties are significantly changed. Also in the case of (b) above, a special coating technique is required to prevent other physical properties from changing and peeling off. In the case of the above (c), a special blending technique is required due to the compatibility with the polymer, and the physical properties may change with changes in the blending ratio. In the case of the above (d), there is a problem that the physical properties of the polymer are deteriorated when the mixed amount increases.

It is therefore an object of the present invention is to solve the technical problems described above, and minimize the impact on other properties, printing Oh that can be finely controlled surface tension of the surface printing layer
It is to provide a fuss blanket .

[0007]

The offset blanket for printing of the present invention comprises a support layer and a support layer.
A printing offset comprising a surface printing layer laminated on the layer
In a blanket, the surface-printed layer is a perfluoroalkyl that lowers the surface tension of the polymer.
Group and acryloyloxy having reactivity with polymer
From a polymer mixed with a surface-modifying agent consisting of a fluorine compound having a group or a methacryloyloxy group in the molecule
It is characterized by being formed . The surface modification
The agent is incorporated into the polymer in a proportion of 0.5 to 30 phr
Is preferred .

That is, the present inventionInIs a surface modifier
Fluorine compounds have the surface tension of polymers in their molecules.
Surface modification site to reduceIs a perfluoroalkyl group
And the reactive site with the polymerIs acryloyloxy
Group or methacryloyloxy groupHave and are compatible
Since it is rich in properties, it can be mixed in the polymer at any ratio.
Surface tension of the polymer depending on the amount
Can be reduced. Moreover, in the above reactive site
The fluorine compound chemically bonds with the polymer.
It is less likely to change other physical properties of the polymer.
It has the characteristic of being bad.Therefore, the surface modifier was mixed.
The present invention has a surface printed layer formed from a polymer.
Husset blanket almost affects other physical properties
Finely control only the surface tension of the surface printing layer without
You can do it.

The surface tension of the polymer in the present invention means
It is a numerical value obtained from the contact angle of droplets formed by the solvent on the surface of the polymer, and the higher the contact angle, that is, the more difficult it is to wet, the lower the surface tension. Perfluoroalkyl group fluorine compound has in the present invention is one <br/> general formula: represented by -C _n F _{2n + 1} (wherein, n is an integer).

Furthermore, acryloyloxy group and methacryloyloxy group fluorine compound has in the present invention,
One general formula: (wherein, R ¹ is hydrogen atom or a methyl _{group.) H 2 C = C (} R 1) COO- represented by.

Specific examples of the fluorine compound in the present invention include "Diefree FB-975", a trade name of perfluoroalkyl acrylate manufactured by Daikin Industries, Ltd. Further, examples of the polymer in which the fluorine compound is mixed include silicone rubber and acrylonitrile-butadiene copolymer rubber (NBR) that have been conventionally used in the surface printing layer of an offset blanket, but the present invention is not limited thereto. Not a thing, but polyisoprene rubber (IR), ethylene-propylene copolymer (EPM, EPDM), chloroprene rubber (C
It is also applicable to polymers such as R), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR).

As the silicone rubber, various conventionally known silicone rubbers can be used. For example, millable silicone rubber that can be kneaded, room temperature vulcanizing (RTV) silicone rubber that cures at room temperature, Examples include injection-moldable LIM silicone rubber. The silicone rubber is polymethyl siloxane and the degree of polymerization is 100-8.
RTV silicone rubber based on liquid silicone gum with a low degree of polymerization of about 00 and degree of polymerization of 6000 to 10000
Millable silicone rubber based on a gel-like silicone gum of a certain degree is conceivable, but in any case, raw silica is an anhydrous silica-based reinforcing filler such as Aerosil, talc,
It is supplied as a rubber compound containing a filler such as mica and a dispersion accelerator. Generally, RTV silicone rubber is mostly polydimethylsiloxane, and the millable silicone rubber is one in which about 0.1 to 0.5 mol% of methyl vinyl group is introduced in order to balance crosslinkability and physical properties. There is. In addition, trifluoropropyl group-introduced FVMQ and phenyl group-introduced PVMQ
Etc. can also be used, and mixtures thereof can be used as well.

The amount of the fluorine compound mixed in the polymer is 0.5 to 30 phr with respect to the polymer. The polymer having such a fluorine compound mixed therein has a lower surface tension depending on the amount of the compound. Therefore, it becomes possible to finely control the transferability of the ink according to the printing conditions and the like. Here, if the amount of the fluorine compound mixed exceeds the above range, other physical properties of the polymer (normal physical properties, swelling, etc.) are deteriorated, and if the amount of the fluorine compound mixed is less than the above range, almost no decrease in surface tension is observed.

[0014] off set blanket of the present invention comprises usually a support layer, a surface printing layer laminated on the support layer. And as above for the surface print layer
By using the surface-modified polymer , the surface tension can be reduced to the optimum range of ink transfer without changing other physical properties, and the ink transfer property from the plate to the offset blanket and the printing from the offset blanket can be performed. It is possible to provide an offset blanket which can almost completely meet the two conflicting requirements of ink transfer to the body.

The surface printing layer is prepared by mixing the polymer with a vulcanizing agent, a filler and the like together with the above surface modifier and molding the mixture.
It is formed by vulcanization by a conventional method. Examples of the vulcanizing agent include benzoyl peroxide, bis 2,
4-dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, p-monochlorobenzoyl peroxide, 2,5-dimethyl-
2,5-bis (t-butylperoxy) hexane, t-
Examples thereof include organic peroxide-based crosslinking agents such as butylcumyl peroxide.

As the filler, anhydrous silicic acid, hydrous silicic acid, calcium carbonate, hard clay, barium sulfate, talc,
Inorganic fillers such as asbestos and graphite and recycled rubber,
Examples include powder rubber, asphalt, styrene resin, and organic filler such as glue. As the support layer for laminating the surface printing layer having the above structure, for example, a plurality of base fabrics impregnated with a rubber material (rubber paste) and at least one compressible layer provided as needed are laminated. The ones created by

The base cloth is woven cloth such as cotton, polyester, rayon and the like. Examples of the rubber material to be impregnated include acrylonitrile-butadiene copolymer rubber and chloroprene rubber. These rubber materials contain a predetermined amount of a vulcanizing agent, a vulcanization accelerator and, if necessary, a thickener and the like. Then, the woven cloth is coated with the rubber agent by an appropriate application means such as a blade coating method. Next, the surface printing layer forming rubber glue made of the above-mentioned specific rubber material is applied to the surface of the support layer through the primer layer and dried, or a sheet-like material formed by calendering or the like is laminated. The obtained laminate is heated and pressurized at a predetermined pressure and temperature for vulcanization to obtain an offset blanket having a compressive layer in the support layer. The compressive layer is prepared by applying a rubber paste in which a water-soluble powder such as salt is dissolved to at least one intermediate cloth, drying and vulcanizing it, and then applying 6-10 to hot water at 60 to 100 ° C. It is formed by immersing for a time, eluting the water-soluble powder and drying.

Further, instead of such a laminated type support layer, a film or sheet such as polyethylene terephthalate (PET), polycarbonate (PC), polypropylene (PP), aluminum foil, and stainless sheet is used as the support layer. Good. The obtained offset blanket is used by being adhered to the peripheral surface of the cylinder of the transfer cylinder either directly or through an undercoating material.

[0019]

[0020]

EXAMPLES Examples 1 to 6 Commercially available silicone rubber (trade name "KE-575u" manufactured by Shin-Etsu Silicone Co., Ltd.) was used as a polymer, and together with a vulcanizing agent, a perfluoroalkyl acrylate (Daikin Product name “Daifree F” manufactured by Kogyo Co., Ltd.
B-975 ") was added at the ratio shown in Table 1 and kneaded with a kneading roll. This was press-vulcanized in a mold at 165 ° C. for 15 minutes, and then secondary vulcanized in an electric oven at 200 ° C. for 4 hours.

The results of the surface tension, normal state test and swelling test of each of the obtained samples are also shown in Table 1. The surface tension of the polymer is calculated by using n-alkane as a solvent,
The contact angle of the droplet formed by the solvent on the polymer surface was measured and determined from Zisman Plot. Contact angle is Kyowa Interface Science
It was measured with a contact angle meter CA-A type manufactured by KK

The normal state test was determined according to JIS-6301. The test items in Table 1 are as follows. M ₁₀₀ : Tensile strength per unit area when the marked line distance extends 100% from the initial state. M ₂₀₀ : Tensile strength per unit area when the marked line distance is increased by 200% from the initial state.

M ₃₀₀ : The marked line distance is 300% from the initial state
It is the tensile strength per unit area when stretched. E _B: is the ratio of the elongation at break of the sample. T _B : Tensile strength at break of sample. H _S : Hardness by A-type hardness tester Swelling test was conducted for each sample (dimensions: 0.5 mm × 2 cm × 2 c
m) is immersed in toluene and ethanol kept at 40 ° C. for 24 hours respectively, and then the sample is taken out. From the weight W ₁ before immersion and the volume W ₂ after immersion, the weight change rate ΔW shown in the following formula Was measured.

ΔW (%) = [(W ₂ −W ₁ ) / W ₁ ] × 100 Further, the volume change rate ΔV shown in the following formula is calculated from the volume V ₁ before immersion and the volume V ₂ after immersion. did. ΔV (%) = [(V ₂ −V ₁ ) / V ₁ ] × 100

[0025]

[Table 1]

Comparative Examples 1 to 6 Comparative Examples 1 to 6 were carried out except that tetrafluoroethylene resin (PTFE, trade name "Lubron" manufactured by Daikin Industries, Ltd.) was used in place of the perfluoroalkyl acrylate in Examples 1 to 6. Each sample was obtained and its physical properties were measured in the same manner as in Examples 1 to 6. The results are shown in Table 2.

[0027]

[Table 2]

From Tables 1 and 2, in Comparative Examples 1 to 6, when the tetrafluoroethylene resin is mixed into the silicone rubber, the surface tension does not change so much and the physical properties of normal state and swelling deteriorate. On the other hand, in the examples, when perfluoroalkyl acrylate is mixed into the silicone rubber as the surface modifier, only the surface tension is decreased according to the mixed amount without substantially changing the physical properties of normal state and swelling. I understand. In the comparative example, the reason why the physical properties are deteriorated is considered that the tetrafluoroethylene resin is hard to be compatible with the silicone rubber. Examples 7 to 12 Instead of the silicone rubber in Examples 1 to 6, NBR
(N230S manufactured by Nippon Synthetic Rubber Co., Ltd.) was used to prepare the compositions shown in Table 3, and press vulcanization was performed at 140 ° C. for 60 minutes, and no secondary vulcanization was performed. Each sample was obtained in the same manner as in Examples 1 to 6 and the physical properties thereof were measured. The results are shown in Table 3.

[0029]

[Table 3]

Comparative Examples 7 to 12 Comparative Examples 7 to 12 were carried out except that tetrafluoroethylene resin (PTFE, trade name "Lubron" manufactured by Daikin Industries, Ltd.) was used in place of the perfluoroalkyl acrylate in Examples 7 to 12. Each sample was obtained and its physical properties were measured in the same manner as in Examples 7 to 12. The results are shown in Table 4.

[0031]

[Table 4]

From the test results of Tables 3 and 4, similarly to the above, in Examples 7 to 12, the physical properties of the normal state and the swelling hardly changed, and only the surface tension decreased in accordance with the mixed amount. On the other hand, in Comparative Examples 7 to 12, the surface tension does not change so much, and the physical properties of normal state and swelling are deteriorated.

[0033]

As described above, according to the present invention, the surface marking
The surface tension of the polymer can be adjusted according to the amount of the surface modifier mixed without changing the physical properties of the polymer that constitutes the printing layer.
Can only be changed so it is offset from the plate
Ink transfer to blanket and offset bra
Ink transfer from the ink cartridge to the printing medium
Offering an offset blanket that meets the contrary requirements
can do.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C08L 101/00 LSY

Claims (1)

[Claims] 1. A support layer and a layer laminated on the support layer.
For offset blanket for printing with surface printing layer
In the above, the surface printing layer has a reactivity with a polymer, which is a perfluoroalkyl group that lowers the surface tension of the polymer.
Having an acryloyloxy group or methacryloyl group
Surface modification consisting of a fluorine compound having a xy group in the molecule
An offset blanket for printing, which is formed from a polymer mixed with a substance . 2. The polymer as the surface modifier is 0.5 to 30.
2. The printing offset according to claim 1 , wherein the offset amount is phr.
Blanket . 3. The offset blanket for printing according to claim 1, wherein the polymer is silicone rubber or acrylonitrile-butadiene copolymer rubber.