JPS63186232A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To improve the ozone and oxidation resistances of a photosensitive resin compsn. by using epichlorohydrin rubber as the base polymer of the compsn. CONSTITUTION:This photosensitive resin compsn. contains epichlorohydrin rubber, a hydrophilic polymer, an ethylenic unsatd. compd. and a photopolymn. initiator. The pref. amt. of the epichlorohydrin rubber is 20-80wt.% of the amt. of the compsn. and that of the hydrophilic polymer is 5-50wt.%. The epichlorohydrin rubber used has no double bond in the principal chain but has ether and allyl bonds forming the skeleton. Thus, superior ozone and oxidation resistances are obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a photosensitive resin composition that has rubber elasticity and is capable of aqueous processing, and particularly relates to a photosensitive resin composition that is applied to flexographic printing plates.

(Prior art) Conventional photosensitive resin plates for flexographic printing are known to react with resin-like solvents, but these printing plates have safety issues for the human body and the environment, such as toxicity and flammability. Ta.

Therefore, as an alternative to this, a photosensitive resin composition capable of water-based processing has been proposed.

For example, a copolymer containing a conjugated diene hydrocarbon and an α,β-ethylenically unsaturated carboxylic acid as essential components and a monoolefinically unsaturated compound, a photopolymerizable unsaturated monomer, and a photosensitized (Japanese Patent Application Laid-Open No. 134855/1989), a method using a photosensitive resin composition containing a hydrophilic agent, a method using a conjugated diene hydrocarbon polymer or a copolymer of a conjugated diene hydrocarbon and a monoolefinic unsaturated compound, and a method using a photosensitive resin composition containing a hydrophilic compound. polymer compound,
There is a photosensitive elastomer composition (JP-A-80-211451) containing a non-gaseous ethylenically unsaturated compound and a photopolymerization initiator as essential components.

(Problems to be Solved by the Invention) The composition can be developed with an aqueous developing solution, such as an alkaline aqueous solution or an alkaline water-organic solvent system, but since the base is a conjugated diene hydrocarbon, it is difficult to develop a flexographic printing plate. The problem is that the ozone resistance, light resistance, and oxidation resistance required for this purpose are insufficient.

(Means for Solving the Problems) As a result of intensive studies, the present inventors solved the above problems by using epichlorohydrin rubber and a hydrophilic polymer as the base polymer, and also improved the water resistance of ink. Ta. That is, the present invention provides (A) epichlorohydrin rubber, (B) 1! This is a photosensitive resin composition characterized by containing an aqueous polymer, (C) an ethylenically unsaturated compound, and (D) a photopolymerization initiator.

(A) Epichlorohydrin rubber in the present invention is a general term for rubbers containing epichlorohydrin as a main component, and is a copolymer of a homopolymer of epichlorohydrin and a cyclic ether such as ethylene oxide and/or allyl glycidyl ether. This epichlorohydrin rubber is marketed as a commercial product, for example, in the United States by Gutdrich and Hilcres, and in Japan by Nippon Zeon and Osaka Soda under the "Ebichromer" (registered trademark) series.

In addition, in the present invention, not only epichlorohydrin rubber but also an elastomer having good compatibility with epichlorohydrin rubber and ozone resistance,
For example, acrylic rubber, polyurethane elastomer, etc. may be blended.

In the present invention, the content of component (A) in the composition is 20% by weight in consideration of physical properties and shape retention as a printing plate.
Above, it is particularly preferably at least 30% by weight, and from the viewpoint of photopolymerizability, it is preferably at most 80% by weight, particularly preferably at most 70% by weight.

Component (B) of the present invention, a hydrophilic polymer, is a polymer that is soluble or swells (dispersed) in water or a developer containing water as a main component, an alkaline aqueous solution, an acidic aqueous solution, an organic solvent, or a surfactant. means.

Examples include polymers that grow hydrophilic groups such as hydroxyl groups, carboxyl groups, amine groups, and sulfonic acid groups and/or polyethylene glycol chains. Specific examples include polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, water-soluble polyurethane, and water-soluble hydrophilic polyurea urethane, water-soluble polyester water-soluble epoxy compound, carboxyl group-containing acrylonitrile-butadiene copolymer, carboxyl group-containing styrene-butadiene copolymer, carboxyl group-containing polybutadiene, polyacrylamide, sodium polyacrylate, carboxyl group, etc. Polyurethane containing a group, polyureaurethane containing a carboxyl group, polyamic acid, etc. can be used, but the present invention is not limited to these.

The content of component (B) in the composition is preferably 5 to 50% by weight, particularly 7 to 40% by weight, taking into consideration water-based developability and water-based ink resistance.

The ethylenically unsaturated compound of component (C) in the present invention contains at least one terminal ethylenic group, and this compound is capable of forming a high molecular weight polymer by free radical initiated chain growth addition polymerization. It is something. Suitable ethylenically unsaturated compounds are unsaturated esters of polyols, especially such esters with α-methylenecarboxylic acid, such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, glycerol diacrylate. , 1,3-propanediol di(meth)acrylate), 1,4-butanediol di(meth)acrylate, 1,2゜4-butanetriol tri(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate ) acrylate, 1,6-hexanethiol di(meth)acrylate, trimethylolpropane tri(meth)acrylate diallyl phthalate, fumaric acid diethyl ester, maleic acid dibutyl ester, and N-methylmaleimide, N-
N-substituted maleimide compounds such as ethylmaleimide and N-laurylmaleimide, oligonitrile and butadiene di(
Examples include oligo(meth)acrylates such as meth)acrylate, oligonitrile urethane(meth)acrylate, and oligourethane')(meth)acrylate.
These may be used alone or in combination.

The proportion of component (C) present in the composition is preferably 1 to 50% by weight, and if it is less than 1% by weight, photopolymerizability will be impaired and no image will remain after development. On the other hand, if it exceeds 50% by weight, shape retention will be impaired. Furthermore, the plate after irradiation with light becomes hard and brittle, making it unsuitable as a flexographic printing plate material, which is not preferable. More preferably, it is 5 to 40% by weight.

Examples of the component (D) photopolymerization initiator in the present invention include benzophenones, benzoins, acetophenones, benzyls, benzoin alkyl ethers, penzyl alkyl ketals, anthraquinones, and thioxanthones. Specifically, benzophenone, chlor benzophenone, benzoin, acetophenone, benzyl, benzoin, methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzyl diethyl ketal. , benzyl diisopropyl ketal, anthraquinone, 2-chloroanthraquinone, thioxanthone, 2
-There are chlor thioxanthone, etc.

These are contained in the composition in an amount of 0.01 to 5% by weight. 0
．． If it is less than 0.01%, the ability to initiate photopolymerization will be impaired. 5%
If the amount is larger than this, it is not preferable because the curing depth cannot be obtained due to its own light shielding, and the image is likely to be chipped during development. More preferably, it is 0.1 to 3% by weight.

In the present invention, in order to simply prevent thermal polymerization without suppressing the photocrosslinking reaction, the requirements (A) to (D) are met.
In addition, 0.001 to 5% by weight of (E) a thermal polymerization inhibitor may be included. Examples of effective thermal polymerization inhibitors include:
hydroquinone, hydroquinone monoethyl ether,
Examples include catechol, pt-butylcatechol, 2,6-di-t-phthyl-p-cresol, and the like.

In addition to the photosensitive resin composition of the present invention, as a plasticizer, liquid rubber such as liquid polybutadiene rubber, liquid polyacrylonitrile butadiene rubber, liquid polystyrene butadiene rubber, liquid imprene rubber, polyvinyl chloride,
It can contain relatively low molecular weight elastomers such as chlorinated polyethylene and chlorinated polypropylene, and fine powders such as silica and diatoms.

A method for preparing a flexographic printing original plate using the photosensitive resin plate composition of the present invention is to dissolve each of the above-mentioned components in a suitable solvent such as tetrahydrofuran, dioxane, methyl ethyl ketone, cyclohexanone, chloroform, etc. in any order. It can be produced by heating and pressing onto a suitable support such as a film of polyester, polyethylene, polypropylene, etc. after removing the . Further, a similar film or a thin layer of polyvinyl alcohol, polyacrylamide, hydroxypropyl cellulose, etc. soluble in an aqueous developer is coated or laminated on a surface different from the support. It also has excellent ink resistance, ink transfer properties, and printing durability. The photosensitive resin composition of the present invention is mainly useful as a flexo printing plate, but it can also be applied to photoresists and sandblasting.
In addition, it can be used as an elastomer that is cured by ultraviolet rays, such as adhesives, films, paints, and others.

(Function) One of the features of the present invention is the use of epichlorohydrin rubber. The epichlorohydrin rubber used in the present invention is a ring-opened copolymer of epichlorohydrin or epichlorohydrin and/or ethylene oxide and/or a cyclic ether such as allyl glycidyl ether, and has an ether bond in the main chain and a chloromethyl group or allyl group in the side chain. It has a base. This rubber does not have double bonds in its main chain, leaving the ether bonds and allyl bonds that form the skeleton, so it is thought to have excellent ozone resistance, heat aging resistance, and excellent oil resistance due to the chloromethyl group. . Showing excellent ozone resistance will significantly improve one of the drawbacks of conventional butadiene-based flexographic printing materials, and the allyl group extended to the side chain not only improves heat deterioration resistance but also has excellent resistance to photopolymerization. It acts as a functional group and can be involved in improving the crosslinking density and solvent resistance of the composition.

In addition, by controlling the blending ratio of hydrophilic polymers,
Water-resistant ink properties are improved.

(Examples) The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

In the examples, parts mean parts by weight.

Furthermore, the hardness of the flexographic printing plate obtained from the composition of the present invention,
Repulsion resilience and ozone resistance were measured by the following methods.

Hardness: Measured at 20°C using a spring type hardness test (type A) according to JIS-6301.

Repulsion modulus: A steel ball with a diameter of 10 m/m (weight 4.16 g) was dropped from a height of 20c11, and the rebound height a) was read and expressed as (a/20) x 100%.

Ozone resistance: A test piece of 5 x 20 x 1 mm was placed under 03 atmosphere (ippm, lm'/lll1n),
The hardness was measured after being left at 25° C. for 24 hours and expressed as a change from the hardness immediately after the test piece was prepared.

Example 1 ■ Preparation of photosensitive resin composition 21.8 parts of hexamethylene diisocyanate, 15.4 parts of dimethylolpropionic acid Polytetramethylene glycol (PG-100 manufactured by Nippon Polyurethane Kogyo 9m)7.
A solution of 6 parts dissolved in 300 parts of methyl ethyl ketone is placed in a flask equipped with a stirrer. In a separate container, acrylonitrile butadiene oligomer containing terminal amino groups (Hycar ATBNX 1300XIE3
(manufactured by Ube Industries, Ltd.) 55.3 parts to 1 part of methyl ethyl ketone
A solution prepared by dissolving 0.00 parts of the solution was added into the above 1 g flask at room temperature with stirring. Nilauric acid di-n
-1.0 part of butyltin was added and the flask was heated at 70° C. for 3 hours with continued stirring. The obtained polymer solution was dried under reduced pressure to remove methyl ethyl ketone to obtain a hydrophilic polymer [I] having a number average molecular weight of 45.000.

The above hydrophilic polymer [25 parts of Eco, 50 parts of polyepichlorohydrin (Ebichroma-H manufactured by Osaka Soda Ell) as epichlorohydrin rubber, 23.5 parts of butadiene oligoacrylate (A-3025, Idemitsu Petrochemical '11), benzyl dimethyl ketal ( 1 part of Irgacure 651 (manufactured by Ciba Geigy Wholesale) and 0.5 part of hydroquinone monomethyl ether were kneaded at 105°C using a heating kneader, and after defoaming, the resulting photosensitive resin composition was heated at 105°C with a heat press machine at 1100 kg. /am' pressure, 125μ
A polyester film with a thickness of 2.8 m was heated and pressed for 1 minute between a polyester film with a thickness of m and a polyester film coated with 2 μm of polyvinyl alcohol on one side on the same polyester film, so that the polyvinyl alcohol coated layer was in contact with the photosensitive resin. I created a sheet.

A polyester film made by Mogami was heated to leave a polyvinyl alcohol film on the photosensitive resin layer, and a negative film containing an image was placed on top of it, and a mercury lamp (manufactured by Dainippon Screen Co., Ltd.) was used to illuminate the film at an illuminance of 25 W/♂, 5 Exposure was performed for minutes. After removing the negative film, 0.5% by weight of hydroxide) I
When development was carried out using a brush at 40° C. for 10 minutes with a Jumium aqueous solution, an image pattern with a relief depth of 1.2 m was obtained. This image pattern faithfully reproduced the image of the negative film used.

Example 2 A solution in which 20 parts of a propylene oxide oligomer containing a terminal amine group (Jeffamine D-2000 manufactured by Mitsui Texaco Chemical 11) was dissolved in 30 parts of tetrahydrofuran, and 4.4 parts of pyromellitic anhydride was dissolved in 2 parts of tetrahydrofuran.
It was added to a solution pre-dissolved in 0 parts at room temperature while stirring.

Acrylonitrile/butadiene oligo for terminal amino base? -(Hycar ATBNX 1300×16
The above reaction solution of propylene oxide oligomer and pyromellitic anhydride was added to a solution obtained by dissolving 36 parts (manufactured by Ube Industries, Ltd.) in a mixed solvent of 100 parts of tetrahydrofuran and 50 parts of methanol while stirring at room temperature. A solution of polyamic acid was obtained. After casting this solution, the solvent was removed by drying under reduced pressure, and the hydrophilic polymer (II)
I got it.

20 parts of the above hydrophilic polymer (II), 50 parts of epichlorohydrin rubber (Ebichroma-H manufactured by Osaka Soda ill),
Butadiene oligoacrylate (8-3025, manufactured by Idemitsu Petrochemical Co., Ltd.) 28.5 parts, benzyl dimethyl ketal 1
A relief pattern was obtained in the same manner as in Example 1 using 5 g of hydroquinone monomethyl ether and
Relief depth 1 faithfully reproduces negative film images
A relief pattern of drunkenness was obtained.

Example 3 Hydrophilic polymer of Example 1 [117.5 parts, epichlorohydrin rubber (Ebichroma-H1 manufactured by Osaka Soda Association) 52
．． 5 parts, epichlorohydrin oligomer (L-1 Osaka Soda i) manufactured by Shun) 15 parts, butadiene oligoacrylate (
When a relief pattern was obtained in the same manner as in Example 1 using 23.5 parts of A-3025 (Idemitsu Petrochemical Co., Ltd.), 1 part of dimethylbenzyl ketal and 0.5 part of hydroquinone monomethyl ether, the image on the negative film was faithfully reproduced. A relief pattern with a relief depth of 0.9 mm was obtained.

Example 4 All the same procedures as in Example 2 were carried out except that epichlorohydrin copolymer (92 mol% epichlorohydrin, 8 mol% allyl glycidyl ether copolymer, Ebichroma-HG Osaka Futatsu ai!) was used as the epichlorohydrin rubber. When a relief pattern was obtained in the same manner as Example 2,
A relief that faithfully reproduced the negative film image was obtained.

Example 5 Copolymer of inbutylene and maleic anhydride (Isopane D
-4, 200 parts of Clareisoprene Chemical (a), 400 parts of methanol, and 3 parts of 2-methylimidazole were placed in a flask equipped with a reflux condenser and a stirrer, and heated at 64°C for 8 hours.
Time reacted. The reaction solution was cast and dried under reduced pressure to obtain a hydrophilic polymer [■].

55 parts of the above hydrophilic polymer [15 parts of epichlorohydrin rubber (manufactured by Ebichroma-H Osaka!!!Fill) 1], monoacrylate of phenol ethylene oxide adduct (manufactured by Aroex M-102ffi Agosei Kagaku 8m) 20 parts, hexamethylene diacrylate 8
．． A relief pattern was obtained in the same manner as in Example 1 using 5 parts of dimethylbenzyl ketal, 1 part of dimethylbenzyl ketal, and 0.5 parts of hydroquinone monomethyl ether. The developing solution in this case is sodium hydroxide/2-(2-butoxyethoxy)ethanol/aqueous solution (0.4 parts of sodium hydroxide, 2 parts of sodium hydroxide,
-(2-Butoxyethoxy)ethanol 15 parts, water 84 parts
．． The procedure was the same as in Example 1 except that 6 parts) was used.

Example 6 As a hydrophilic polymer, 20 parts of hydroxypropyl methyl cellulose (TC-5R (KM Kagaku H1), epichlorohydrin copolymer (equimolar copolymer of epichlorohydrin and ethylene oxide, manufactured by Nippon Zeo 7 [1 part,
H'ldrin 200) 50 parts, acrylonitrile butadiene oligoacrylate) (HYCARV
28.5 parts of an equal weight mixture of TBNX 1300 A relief pattern was obtained in the same manner as in Example 1, and a relief that faithfully reproduced the image of the negative film was obtained.

Example 7 25 parts of methacrylic acid/acrylonitrile/butadiene copolymer (Nipole 1072 manufactured by Nippon Zeon A21), epichlorohydrin rubber (Ebichromer H1 Osaka Soda fl
l) 50 parts, phenol ethylene oxide adduct monoacrylate (Aronix M2O3 manufactured by Toagosei Kagaku H1) 13.5 parts, hexamethylene diacrylate 1
A relief pattern was obtained in the same manner as in Example 1 using 0 part of dimethylbenzyl ketal, 1 part of dimethylbenzyl ketal, and 0.5 part of hydroquinone monomethylene ether. The developing solution in this case is the same as in Example 5, sodium hydroxide/2-(2-butoxyethoxy)ethanol/aqueous solution (sodium hydroxide 0
．． 5 parts, 2-(2-butoxyethoxy)ethanol 15
and 84.6 parts of water) for 30 minutes at 50''C.The relief image obtained with a relief depth of 1fiI11 faithfully reproduced the image of the negative film.

Comparative Example 1 Acrylonitrile-butadiene copolymer (acrylonitrile 21%, butadiene 79% copolymer, Nippon Zeon 0
1! Example 1 was prepared using 50 parts of Hycar 1014, manufactured by Co., Ltd., in place of the epichlorohydrin rubber in Example 1.
A sheet of the photosensitive resin composition was obtained in the same manner as in Example 1, and a relief was obtained in the same manner, but the relief depth was 0.7 mm and the developability was worse than in Example 1.

Comparative Example 2 Styrene O-butadiene copolymer (styrene 23.5%,
A relief was obtained in the same manner as in Comparative Example 1 using 50 parts of butadiene 76.5% copolymer and Nipole 1507 (manufactured by Nippon Zeon σ-ku), but the relief became extremely cloudy and a clear image could not be reproduced. Ta.

Reference Example Table 1 shows the measurement results of the hardness, rebound modulus, and ozone resistance of the reliefs obtained in Examples 1 to 7 and Comparative Examples 1 to 2.

The following margin (effects of the invention) Since the photosensitive resin composition of the present invention uses epichlorohydrin rubber as the base polymer, it has better ozone resistance, oxidation resistance, etc. than those using conventional conjugated diene rubber as the base polymer. Excellent. In addition, epichlorohydrin rubber has a slightly more hydrophilic property than conventional conjugated diene rubber, so the content of hydrophilic polymers can be reduced, resulting in various advantages such as improved water-based ink resistance. have.

Claims (3)

[Claims] (1) (A) epichlorohydrin rubber, (B) hydrophilic polymer, (C) ethylenically unsaturated compound, and (D)
A photosensitive resin composition containing a photopolymerization initiator. (2) Add 20% epichlorohydrin rubber to the entire composition.
80% by weight of the photosensitive resin composition according to claim (1). (3) The photosensitive resin composition according to claim (1), which contains a hydrophilic polymer in an amount of 5 to 50% by weight based on the total composition.