JPS609250B2 - Photosensitive resin composition - Google Patents

Description

Detailed Description of the Invention The present invention provides an excellent photosensitive material that has low rubber hardness and sufficient rubber elasticity by irradiating active light including ultraviolet rays for photocuring, and then dissolving the unirradiated areas with an aqueous developer. The present invention relates to a photosensitive resin composition that can provide a flexible resin flexographic plate.

Conventionally, natural rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and other synthetic rubbers have been used as materials for flexographic printing plates. This is because flexographic printing mainly prints on papers with extremely rough surfaces, such as cardboard and heavy bags, and is therefore limited to printing plates with low rubber hardness, that is, rubber elasticity. To produce such flexographic printing plates, skilled craftsmen engrave directly onto a rubber plate by hand, or apply a photosensitive resin to zinc or magnesium sakagami, apply a negative film, expose it, develop it, and then use an inorganic acid. A corroded metal plate was prepared, and a thermosetting resin mainly composed of phenolic resin was applied to the metal corroded plate and pressurized to create a matrix, and a stimulant was added to the resulting matrix. There is a method of obtaining a rubber reproduction plate by heat-pressing and vulcanizing various synthetic rubbers including natural rubber. However, hand engraving is unsuitable for modern printing, as craftsmen make each plate one at a time, which takes a long time, making it difficult to create fine letters and designs, and making photo plates impossible. There are drawbacks, and furthermore, the number of craftsmen has been decreasing in recent years.

Rubber duplicating plates are currently mainly used for flexo printing plates, but as mentioned above, a metal corroding plate must first be made, and the treatment liquid containing inorganic acids discharged during the process of corroding metals can reduce water quality. We have reached the stage where we have to take into account the effects of strong acids on the human body, which can cause pollution and the effects of using strong acids.

Furthermore, the cost of rubber duplication plates has been rising in recent years as the series of processes for producing rubber duplication plates from a matrix takes a long time and labor costs have soared. Regarding plate performance,
Since two steps are required to go from a metal corrosion plate to a rubber duplication plate, the reproducibility of the originally used original is poor, and there are drawbacks that reduce plate performance, such as missing dots in the pongee lines and end point areas. It is not possible to handle a sufficient number of screen lines to satisfy the demand for high-end printed matter as packaging expands. Rubber reproduction plates require high-temperature treatment and vulcanization during the production process, so the resulting plates suffer from heat shrinkage, so various measures have been taken to prevent shrinkage.
It is difficult to solve this problem, and it must be said that it is extremely inappropriate for multicolor printing, which requires precision. Flexographic printing plates produced by hand engraving and rubber duplication methods have various drawbacks, and photosensitive resin flexographic plates have been introduced to solve these drawbacks.

In other words, the process of making a flexographic printing plate with photosensitive resin is ■
A negative film is applied to a liquid photosensitive resin coated on a transparent support such as a polyester film, or to a solid photosensitive resin on which a photosensitive resin layer has been previously held, and active light including ultraviolet rays is irradiated. , (1) Dissolving and removing the unirradiated area, and (2) Drying, which are extremely simplified processes, so anyone can do the work without requiring any skill. There is no need for high-temperature processing when making rubber duplication plates, and a plate that faithfully transfers the negative film can be obtained, so it has high resolution and can handle not only multicolor printing but also screen line counts of 15 eaves/inch or more. Recently, a trend has begun to change from gravure printing, which has been synonymous with high-quality printing. Several photosensitive resin flexo plates are currently on the market, but the current situation is that they are not satisfactory in all aspects. In other words, in order to convert the rubber reproduction plate directly into a photosensitive resin, a photopolymerizable unsaturated compound and a photosensitizer are added to synthetic rubber such as styrene-butadiene rubber or acrylonitrile-butadiene rubber to create a photosensitive resin master plate. In order to produce this, a negative film is applied and exposed to light to create crosslinks between rubber molecules, creating a latent image on the original plate, which is developed by taking advantage of the difference in solubility. , chlorinated hydrocarbons such as percrene are mainly used as the developer. Therefore, special measures have been taken to the developing device to prevent organic solvent from leaking to the outside as much as possible. However, when installing or removing plates from the developing device, workers may not come into direct contact with the organic solvent. You will inhale the vapor. These chlorinated solvents are not only harmful to the human body, but also
When used in large quantities, it must be regulated by the Fire Service Act, and this is a major drawback of commercially available photosensitive resin flexo plates. Furthermore, since it is mainly composed of rubber with a high molecular weight, the solubility of unexposed areas during development is poor, so the rate of dissolution is increased by artificially rubbing the zero plate surface with a brush. When such an operation is carried out, there are also disadvantages in that the highlighted portions of halftone dots with a large number of screen lines are deleted, and the shoulders of the relief are rounded, resulting in unclear printed matter. In order to solve these drawbacks of photosensitive resin flexo plates, the present inventors developed [11(1) Conjugated diolefin hydrocarbons ■ and Q,
8-ethylenically unsaturated carboxylic acid B} as an essential component, and a monoolefinically unsaturated compound [C' and A:
Contains a copolymer containing 10 to 95 mol%, B: 5 to 90%, C: 0 to 85 mol%, (0) a photopolymerizable unsaturated monomer, and (m) a photosensitizer. (1) At least a part of the Q,8-ethylenically unsaturated carboxylic acid {B) contained in the copolymer is an alkali metal salt, ammonium salt, or amine salt. If a photosensitive resin composition containing a copolymer, (0) a photopolymerizable unsaturated monomer, and (a) a photosensitizer is used, an aqueous developer containing an inorganic alkali or water can be used. It was discovered that a new flexographic printing plate could be obtained that could be developed quickly and the resulting printing plate had flexibility, rubber elasticity, and good water resistance, and filed a patent application earlier (Japanese Patent Application Laid-Open No. 52-134655, Japanese Patent Publication No. 134-655).
10648).

The composition of the invention of the above-mentioned earlier application {1' and became. As a result of further intensive research on this point, in the inventions of these earlier applications, as a part of the photopolymerizable unsaturated monomer, the general formula (R, , R2 is hydrogen or a methyl group, R3 is an alkyl group having 1 to 12 carbon atoms) When using a photosensitive resin composition using a monomer represented by a group (n = an integer of 1 to 23), it has sufficient flexibility and rubber elasticity, and can be used as a Sakaki plate for printing on a phase surface such as cardboard. The inventors discovered the fact that an excellent photosensitive resin flexo plate can be produced and completed the present invention. That is, the first invention of the present invention has (1) a conjugated diolefinic hydrocarbon compound and Q,8-ethylenically unsaturated carboxylic acid (B) as essential components, and a monoolefinic unsaturated compound therein. A: 10-98 mol%, B: 2-90 mol%, C: 0-90 mol%
A copolymer containing 85 mol% and (0) general formula (R
、． R2 is hydrogen or a methyl group, R3 is an alkyl group having 112 carbon atoms, n = an integer of 1 to 23) All photopolymerizable unsaturated monomers added A photosensitive resin composition characterized in that it contains a photopolymerizable unsaturated monomer and (m) a photosensitizer, which are mixed so as to account for 5 to 95% by weight of the photosensitive resin composition, and further comprises a second photosensitive resin composition. The invention provides Q,8 contained in the copolymer (1) of the first invention.
- A photosensitive resin composition in which at least a portion of the ethylenically unsaturated carboxylic acid legs is an alkali metal salt, ammonium salt or amine salt.

As the conjugated diolefin hydrocarbon of the polymer of the present invention, 1,3-butadiene, isoprene, chloroprene, dimethylbutadiene, etc. are preferably used.

Conjugated diolefin hydrocarbons may be used alone or
Two or more types may be mixed and used as long as the total amount is within the range of 10 to 98 mol%. When these conjugated diolefin hydrocarbons are polymerized and incorporated into a copolymer, double bonds remain in the main chain or side chain of the copolymer, so a photopolymerizable unsaturated monomer (described later) is formed by a photoreaction. The mer radical is added to the double bond, and the composition after photoreaction not only forms a strong three-dimensional network structure, but also has enhanced water resistance and solvent resistance. Further, the conjugated diolefin hydrocarbon contained in the copolymer can impart flexibility, ie, rubber elasticity, which is required for a flexographic printing plate. If the proportion of the conjugated diolefin hydrocarbon in the copolymer is less than 10 mol%, the above-mentioned three-dimensional crosslinking property and the flexibility required as a flexographic printing plate will be lacking, and the intended photosensitive resin flexographic plate cannot be created.

In addition, if it exceeds 98 mol%, Q contained in the copolymer,
The amount of 3-ethylene unsaturated carboxylic acid becomes relatively small, and the affinity of the photosensitive resin layer containing the copolymer as one component for a dilute aqueous alkaline solution decreases, making it impossible to use the desired development method. . Q,3-ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, crotonic acid, itaconic acid, itaconic anhydride, monoethyl maleate,
Examples include monoesters such as monoethyl fumarate and monoethyl itaconate, citraconic acid, and mesaconic acid.

These Q,3-ethylenically unsaturated carboxylic acids must be contained in the copolymer in an amount of 2 to 90 mol%, and 2
If it is less than mol %, the proportion of hydrophilic groups in the copolymer decreases, making it impossible to satisfy alkaline developability.

In addition, copolymers containing more than 90 mol% of Q,8-ethylenically unsaturated carboxylic acid have decreased rubber elasticity, and can be obtained by exposing and developing a photosensitive resin layer containing the copolymer as one component. It has the disadvantage that the water resistance of the printing plate decreases and the plate lacks flexibility. Q,8-ethylenically unsaturated carboxylic acids may be used alone or in combination of several types as long as the total amount is within the range of 2 to 90 mol%. Although the monoolefinically unsaturated compound does not need to be contained in the copolymer of the present invention, it is added to improve the mechanical properties such as the rubber elasticity, strength, elongation degree, etc. of the printing plate made of the copolymer as one component. This is because the purpose is to improve the printing characteristics of the printing plate, and to improve the printing surface such as the ink receptivity and ink transferability of the printing plate. Examples of monoolefinically unsaturated compounds include styrene, Q-methylstyrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, acrylonitrile, methacrylonitrile, pinyl chloride, vinylidene chloride, acrylamide, methacrylamide, vinyl acetate, general formula (wherein R is hydrogen or a methyl group, R2 is 1 carbon atom to 18 alkyl groups), such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, imbutyl acrylate, te-9-butyl acrylate, n-bentyl acrylate. Acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nasyl acrylate, lauryl acrylate, n
- acrylates or methacrylates such as octadecyl acrylate or their methacrylates.

In addition, the general formula (R,, R2 is hydrogen or a methyl group, R3 is a carbon number of 1 to
alkoxyalkyl acrylate or methacrylate, alkoxypolyalkylene glycol acrylate or methacrylate, dimethyl maleate, jetyl maleate, dibutyl maleate, dioctyl maleate, Gesters of dicarboxylic acids such as dimethyl fumarate, jetyl fumarate, dibutyl fumarate, dioctyl fumarate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, dioctyl itaconate, 2-hydroxyethyl acrylate, 2-hydroxypropyl Esters of hydroxyalkyl alcohols such as acrylates or their methacrylates, benzyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, glycidyl acrylate or the like.
Acrylates or methacrylates having a cyclic side chain, such as these methacrylates, and Aronic type monomers M-5500 and M-5700 manufactured by Toagosei Chemical Industry Co., Ltd. are also preferably used.

These may be used as a mixture of two or more types as long as the total amount does not exceed 85 mol%. When the content of the monoolefinic unsaturated compound in the copolymer exceeds 85 mol%, the amount of bonding of the conjugated diolefinic hydrocarbon and Q,8-ethylenically unsaturated carboxylic acid decreases, so Three-dimensional crosslinkability, rubber elasticity, alkali developability, etc., which are the objectives of the present invention, cannot be satisfied. Preferable copolymers used in the present invention are those containing A: 30 to 95 mol%, B: 5 to 60 mol%, and C: 0 to 60 mol%.

In the present invention, the photopolymerizable unsaturated monomer has the general formula (R,
, R2 represents hydrogen or a methyl group, R3 represents an alkyl group having 1 to 12 carbon atoms, and n = an integer of 1 to 23.

), alkoxypolyalkylene glycol acrylates or methacrylates, such as methoxyethyl acrylate, butoxyethyl acrylate, methoxyisopropyl acrylate, butoxyisopropyl acrylate or their methacrylates, ethoxy Acrylates or methacrylates such as diethylene glycol acrylate, butoxydiethylene glycol acrylate, ethoxydipropylene glycol acrylate, butoxydipropylene glycol acrylate or their methacrylates, methoxytetraethylene glycol acrylate, methoxy nonaethylene glycol acrylate, methoxytetrapropylene glycol acrylate, methoxy nonapropylene Acrylates or methacrylates such as glycol acrylate or their methacrylates account for 5 to 50% of the total photopolymerizable unsaturated monomers.
It is necessary to account for 95% by weight, preferably from 10 to 8% by weight.

These photopolymerizable unsaturated monomers impart flexibility and rubber elasticity derived from side chain ether groups to the photosensitive resin plate containing the photopolymerizable unsaturated monomers. If the photopolymerizable unsaturated monomer of the general formula is less than 5% by weight of the total amount of photopolymerizable unsaturated monomers added, flexibility and rubber elasticity can be achieved in the photosensitive resin plate, which is the object of the present invention. It has little effect,
If it exceeds 95% by weight, these effects can be sufficiently provided, but the photocuring speed in the process of creating a bath image by irradiating the photosensitive resin layer with ultraviolet rays will decrease by 4.0%, making it difficult to create a plate that can withstand practical use. This has the disadvantage that the exposure time must be long.

Photopolymerizable unsaturated monomers used in combination with this pond include unsaturated aromatic compounds such as styrene, Q-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, diisoprobenylbenzene, and divinylbenzene. : o-unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile, methyl acrylate, ethyl acrylate, propyl acrylate, n-
butyl acrylate, imptylacrylate, rt
-butyl acrylate, n-bentyl acrylate, n-
Acrylates or methacrylates of alkyl alcohols such as hexyl acrylate, 2-ethylhetaxyl acrylate, n-octyl acrylate, n-decyl acrylate, lauryl acrylate, n-octadecyl acrylate or their methacrylates: 2-hydroooxyethyl Acrylates or methacrylates of hydroxyalkyl alcohols such as acrylate, 2-hydroxypropyl acrylate or their methacrylates; pendyl acrylate, cyclohexyl acrylate, tetrahydrotaflufuryl acrylate,
Acrylates or methacrylates with a cyclic side chain such as glycidyl acrylate or their methacrylates, Q, 3 such as maleic acid, fumaric acid, maleic anhydride, crotonic acid, itaconic acid, itaconic anhydride, citraconic acid, mesaconic acid, etc. - Ethylenically unsaturated carboxylic acids; monoesters of unsaturated polycarboxylic acids such as monoethyl maleate, monoethyl fumarate, monoethyl itaconate, etc.: dimethyl maleate, jetyl maleate, dibutyl maleate, dioctyl tamaleate, dimethyl fumarate , esters of unsaturated polyhydric carboxylic acids such as diethyl fumarate, dibutyl fumarate, dioctyl fumarate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, dioctyl itaconate; acrolylamide, methacrylamide, N,N Acrylamides such as '-methylenebisacrylamide and N,N'-hexamethylenebisacrylamide or their methacrylamides; ethylene glycol diacrylate or dimethacrylate, diacrylate of polyalkylene glycol (alkylene glycol alone 2 to 2 needles) or dimethacrylates; diacrylates, triacrylates, tetraacrylates, or di-, tri-acrylates of polyhydric alcohols such as glycerin, bentaerythritol, trimethylolalkane, tetramethylolalkane (alkanes include methane, ethane, and propane); , tetramethacrylate: Aronic type monomer M-5500, M-5700, M-6100, M-6 manufactured by Toagosei Chemical Industry Co., Ltd.
A series of oligoacrylates of 300, M-8030, M-8060; Diarylidenebentaerythrit and its modified products, 2,2'-bis(4-methacryloxydiethoxyphenyl)propane, 2,2' -bis(4-acryloxydiethoxyphenyl)propane, 2,2-bis(4
-acryloxyfuropyroxyphenyl)propane, and the like.

These photopolymerizable unsaturated monomers contain 5 to 2
00% by weight, preferably 10 to 10% by weight. Within this range, two or more types can be used in combination. If it is less than 5% by weight, the curing of the photosensitive resin layer and the mechanical strength of the printing plate cannot be sufficiently improved, and if it exceeds 200% by weight, the elasticity of the copolymer rubber will be significantly impaired and the solvent resistance will be reduced. It has disadvantages such as decreased sexual performance.

Preferred are inorganic alkali salts, lithium hydroxide, sodium hydroxide, potassium hydroxide, and ammonia used when synthesizing the carboxylate of the copolymer (1) of the present invention, and the alkali salts are lithium carbonate, sodium carbonate. , potassium carbonate,
Ammonium carbonate, etc.

In addition, amine compounds are also preferably used, including primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and metaljethylamine,
Examples include alcohol amines such as dimethylethanolamine and triethanolamine, and cyclic amines such as morpholine. These are Q,8 contained in copolymer (1)
- It is used in an amount of 0.05 to 1.0, preferably 0.2 to 1.0 equivalent per equivalent of carboxyl group of the ethylenically unsaturated carboxylic acid. It is also possible to mix and use different types of alkali within this range. In this way, the copolymer (
At least a part of the B-ethylene unsaturated carboxylic acid contained in 1) is converted into an alkali metal salt, an ammonium salt,
Alternatively, when an amine salt is used, water can be used as a developer to elute the unexposed area after photocuring. If the amount added is less than 0.05 equivalent, the copolymer itself will not dissolve in water, making water development impossible. Examples of the photosensitizer used in the present invention include Q-diketone compounds such as diacetyl and benzyl, which are commonly used as photoreaction initiators, acyloins such as benzoin and piparoin, and benzene,
Examples include acyloin ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin isoprobyl ether, and polynuclear quinones such as anthraquinone and 1,4-naphthoquinone.

The amount of photosensitizer added is 0.1 to 1% by weight, preferably 1 to 5% by weight, based on the copolymer. 0.1% by weight
If it is less than 1% by weight, sufficient curing cannot be given to the photosensitive resin layer, and if it exceeds 1% by weight, all of the added photosensitizer does not participate in the reaction, which is not only uneconomical, but also
In some cases, the compatibility with the copolymer or photopolymerizable unsaturated monomer is poor, resulting in non-uniform dispersion.

・Some of the commercially available photopolymerizable unsaturated monomers mentioned above usually contain a small amount of a thermal polymerization inhibitor such as p-methoxyphenol, but this has no effect on the exposure of the photosensitive resin layer. Rather, since it acts as a storage stabilizer for the photosensitive resin composition, when preparing the composition, the thermal polymerization inhibitor can be added as is without being removed from the photopolymerizable unsaturated monomer. Furthermore, if necessary, hydroquinone, p-methoxyphenol, p-rt-butylcatechol, 2,6-di-butyl-p-cresol,
Pi. Hydroxy aromatic compounds such as triol, quinones such as benzoquinone, p-torquinone, p-xyloquinone, and amines such as phenyl-Q-naphphthylamine are added in an amount of 0.01 to 2% by weight based on the copolymer. can do. Since the photosensitive resin composition of the present invention is a liquid photosensitive resin composition or a rubber-like solid photosensitive resin composition, it may be necessary to use a spacer with an appropriate thickness to make a constant film thickness.
It can be coated onto a support using a roll coater or the like, or it can be formed into a photosensitive resin layer of a constant thickness by compression molding, extrusion molding, etc., exposed to light with a negative film, and developed to form a photosensitive resin relief plate.

The photosensitive resin letterpress plate has high rubber elasticity and is therefore ideal for flexographic printing plates, and as a support for supporting the resin layer, a support or a plastic film having the same degree of rubber elasticity as the photosensitive resin composition can be used. Examples include sheets of natural rubber, styrene-butadiene rubber, butadiene rubber, acrylonitriloptadiene rubber, isoprene rubber, ethylene-propylene rubber, crystalline 1,2-butadiene resin, soft vinyl chloride resin, etc. Plastic film made of polyester, polypropylene, polystyrene, nylon, vinylidene chloride, polyethylene, etc. Further, grained aluminum plates, iron plates, zinc plates, magnesium plates, etc. can also be used as supports for using the photosensitive resin of the present invention in fields such as newspaper printing and general commercial printing. One of the features of the present invention is the developability with a dilute alkali aqueous solution or water, but the alkali used may be any ordinary alkali, such as sodium hydroxide, potassium hydroxide,
A low concentration aqueous solution of about 0.1 to 1.0% of lithium hydroxide, ammonia, sodium carbonate, potassium carbonate, lithium carbonate, etc. is used as the developer.

Moreover, the photosensitive resin composition of the present invention can of course be developed not only with an alkaline aqueous solution but also with an organic solvent such as alcohol, ketone, or aromatic hydrocarbon.

Since the photosensitive resin composition of the present invention has high photosensitivity, exposure time can be shortened, and its solubility in dilute alkaline aqueous solutions and water is extremely good, allowing development in 1 to 2 minutes.

Since printing can be performed immediately after drying, the complicated manufacturing process and manufacturing time of conventional rubber letterpress plates for flexographic printing can be greatly improved. In addition, it is of course possible to print with solvent-based flexo ink, but because it has good water resistance despite being alkali-soluble, it has become possible to print with water-based flexo ink, which is now replacing solvent-based flexo ink due to air pollution concerns. . The photosensitive resin composition of the present invention not only provides resin plates for full lexographic printing, but also plates for newspapers, general commercial printing, offset PS plates, name plates, printed wiring displays, photoadhesives, etc. It can also be widely used as a photosensitive material for pharmaceuticals.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples in any way unless it exceeds the gist thereof.

Example 1 63.5 of a butadienomethyl methacrylate/acrylic acid = 55/30/15 (molar ratio) copolymer polymerized using methanol as a solvent and N,N'-azobisisobutyronitrile as an initiator. 126% by weight solution was placed in a 500cm separable flask equipped with a fly rod, and further added as photopolymerizable unsaturated monomers, 322% ethoxydiethylene glycol acrylate and 32% nonaethylene glycol dimethacrylate (ethoxydiethylene glycol acrylate). (5% by weight, based on the total photopolymerizable unsaturated monomers), 2.4% penzoinisopropyl ether as a photosensitizer and 0.4% p-methoxyphenol as a storage stabilizer. was added and stirred until a homogeneous solution was obtained.

The separable flask was immersed in a water bath controlled at 4000 °C, and methanol was distilled off under reduced pressure while the contents were immersed in water to prepare a liquid photosensitive resin composition.
Approximately 99% of this liquid photosensitive resin composition was placed on a polyester film (8 x 8 skin, 100 layers thick), a 1.5-thickness baser was placed on the outside of the polyester film, and a polybutadiene resin film "Neorap" ( A glass plate (13×
13 skin, thickness 5 skin) on top of the composition to give a thickness of 1.
A photosensitive resin layer on the fourth side was prepared. After irradiating the glass plate with ultraviolet rays from a 250W ultra-high pressure mercury lamp for 2 minutes from the top 60 degrees of the glass plate, spray development was performed with a 0.5% sodium hydroxide aqueous solution for 1 minute, and a printing plate faithful to the original image was produced. Also, the thickness is 3. 3 without using negative film using the sub-baser of the enemy
Rubber hardness (Shore A hardness,
2000 measurement) is 39, and the rebound modulus (JISK
6301) was 47%, indicating that the printing plate was excellent as a photosensitive resin flexo plate.

When printing on cardboard using the printing plate thus obtained, printed matter with good ink transfer properties was obtained despite the roughness of the cardboard surface.

Comparative Example 1 A photosensitive resin plate was prepared in the same manner as in Example 1 except that 2-ethylhexyl acrylate was used in place of ethoxydiethylene glycol acrylate, and the rubber hardness was Despite being as low as 51,
The rebound modulus was as low as 10%, and there were parts of the printed matter where the ink did not transfer, making it undesirable as a flexographic printing plate material.

*Examples 2 to 6
, Comparative Examples 2 to 3 The ratio of ethoxyjethylene glycol acrylate and nonaethylene glycol dimethacrylate in Example 1 was changed, plate making was carried out in exactly the same manner as in Example 1, and the rubber hardness and rebound modulus were measured. Table 1 I got the result.

Table 1 Total photopolymerization of ethoxydiethylene glycol acrylate, raw bag, rubber hardness, impact elasticity modulus, and weight yield per unit weight)
Cooperation Example 2 10
50 253 30
43 314 70 35
505 90 33
51 Comparative Example 2 0 57
83 100 25
20 The photosensitive resin plates obtained in Examples 2 to 6 had low hardness and rubber elasticity, and were excellent as photosensitive resin flexo plates.

However, as shown in Comparative Examples 2 and 3, if ethoxydiethylene glycol acrylate is not contained in the photopolymerizable unsaturated monomer, the rubber hardness increases and the rebound modulus decreases, resulting in insufficient performance as a flexo plate. If ethoxydiethylene glycol acrylate is used only as a photopolymerizable unsaturated monomer, the decrease in photocuring speed due to monofunctionality may cause curling of fine characters, independent thin lines, etc. Both of them are inferior to the one of the present invention as a photosensitive resin flexo plate because the reduction in crosslinking density makes the plate brittle. Examples 6 to 12 The photopolymerizable unsaturated monomer shown in Table 2 was used in place of the ethoxyjethylene glycol acrylate in Example 1, and the plate was made using the same machine as in Example 1, and the comb hardness and rebound modulus were measured. was measured.

Table 2 Amount of monomers of photochromic unsaturated fo
Rubber hardness (repulsion modulus omitted) Example 6 Etkinethyl acrylate 52 337
Ethquin ethyl methacrylate 53
308 Butquin ethyl acrylate
38 429 Methoxotetraethylene glycolme 47
44 Tacrylate 10 Metquin nonaethylene glycol meth 42 48 Acrylate 11
Methoxypolyethylene glycol meth 3
Both of the 5 and 52 acrylates (n=23) gave excellent printing plates as photosensitive resin flexographic plates, and the print quality of the printed matter was also good.

Examples 13-20 Polymerization using methanol as a solvent and N,N'-azobisisobutyronitrile as an initiator Table 3
The dry weight of each copolymer solution shown in 100 was 28% butoxyethyl acrylate and 42% nonaethylene glycol dimethacrylate (the concentration of butoxyethyl acrylate was 4% by weight based on the total photopolymerizable unsaturated monomers).
), 3 parts of benzoin isopropylene, and 0.5 parts of p-methoxyphenol were added, and methanol was removed under reduced pressure to prepare a liquid photosensitive resin composition. Plate making was carried out in exactly the same manner as in Example 1, rubber hardness and rebound modulus were measured, and cardboard printing was carried out, and it was found that these photosensitive resin plates were excellent as plates for flexographic printing. . Table 3 Copolymer composition Rubber hardness Impact modulus Phosphorus Example 13 BO/EMA/A
A=55/25/20 42 40
14 BD/n-BA/AA=58/17/25
50 4115 BD/2-EH
MA/IA=68/18/14 59 3
316 BD/LMA/IA=70/15/15
58 3717 BD/AN/IA=
75/20/5 54 4
518 BD/ETA/AA=65/15/20
43 4719 BD/8TMA/
AA〒63/17/20 45
452o BD/OA/AA=57/24/19
55 49 However, BD = 1,3-butadiene, EMA = ethyl methacrylate, AA! Acrylic acid, n-BA=n-butyl acrylate, 2-EH
MA; 2-ethylhexyl methacrylate, LMA = lauryl methacrylate, IA = itaconic acid, AN = acrylonitrile, ETA = ethoxyethyl acrylate,
ETMA=ethoxyethyl methacrylate, CA=ethoxydiethylene glycol acrylate, and the ratio is a molar ratio.

Examples 21 to 26 The dry weight of the copolymer solution of butadiene/n-butyl acrylate/acrylic acid = 58/17/25 (molar ratio) used in Example 14 was 100, and the photopolymerizability shown in Table 4 was Add the unsaturated monomer, and further add 2.5 mm of penzoin methyl ether and 0.5 mm of hydroquinone to make a homogeneous solution, and remove methanol under reduced pressure to obtain a transparent liquid photosensitive resin composition. was created.

Table 4 Total photopolymerization Hardness Elastic modulus of antipolymerizable polyacrylate Rubber Total photopolymerization hardness Elastic modulus Examples of photopolymerization biounsaturated polymers Acidity for saturated monounsaturated polymers Covalent polymer powder
(Weight*) 21 Ethoxydiethylene glycol 60
83.3 60
49 acrylate/TMPT22 /A
P-9G 75 40
52 4323 〃 /4M-80
30 60 83.3
61 4024 〃 /B
P8-4 70 57
55 5325 〃 /2-HE
MA 55 40
42 5526 〃 /GMA
55 40 45
51 However, TMPT = trimethylolpropane trimethacrylate, AP-93 = nonapropylene glycol diacrylate, AM-8030 = Aronix M-8
030, BPE-4-2,2'-bis(4-methacryloxydiethoxyphenyl)propane, 2-HEMA=2
-Hydroxyethyl methacrylate, GMA=glycidyl methacrylate.

Plates obtained from these photosensitive resin compositions had good plate-making evaluations, rubber hardness, and rebound modulus, and were useful as flexo plates.

Example 27 Butadiene/methyl methacrylate/used in Example 1
Acrylic acid = 55/30/15 (mole ratio) copolymer 6
Pour the 3.5% by weight solution into a 500ml separable flask equipped with a cylindrical rod, add an aqueous solution of 115% water and 11.9% potassium hydroxide, and stir until it becomes a homogeneous solution. ``The number of carboxyl groups in the copolymer is 0.''
．． A potassium salt of the copolymer corresponding to 5 equivalents was synthesized.

Claims (1)

[Claims] 1 (I) Conjugated diolefin hydrocarbon (A) and α, β
- an ethylenically unsaturated carboxylic acid (B) as an essential component, and a monoolefinic unsaturated compound (C) as an essential component;
: 10-98 mol%, B: 2-90 mol%, C: 0-8
Copolymer containing at a ratio of 5 mol% and (II) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (R_1, R_2 are hydrogen or methyl group, R_3 is an alkyl group having 1 to 12 carbon atoms, n = A photopolymerizable unsaturated monomer (representing an integer from 1 to 23) is mixed so that the photopolymerizable unsaturated monomer represented by A photosensitive resin composition comprising a saturated monomer and (III) a photosensitizer. 2 (I) Conjugated diolefin hydrocarbon (A) and α, β
- an ethylenically unsaturated carboxylic acid (B) as an essential component, and a monoolefinic unsaturated compound (C) in A:1
0 to 98 mol%, B: 2 to 90 mol%, C: 0 to 86 mol%, and at least a part of the α,β-ethylenically unsaturated carboxylic acid (B) is an alkali metal salt, ammonium There are copolymers that are salts or amine salts, and (II) general formulas ▲ mathematical formulas, chemical formulas, tables, etc. ▼ (R_1, R_
2 is hydrogen or a methyl group, R_3 is an alkyl group having 1 to 12 carbon atoms, and n is an integer of 1 to 23) All photopolymerizable unsaturated monomers added A photosensitive resin composition comprising a photopolymerizable unsaturated monomer and (III) a photosensitizer, which are mixed so as to account for 5 to 95% by weight of the monomers.