WO1993016414A1

WO1993016414A1 - Photosensitive composition for flexographic plate material

Info

Publication number: WO1993016414A1
Application number: PCT/JP1993/000152
Authority: WO
Inventors: Kazunori Kanda; Hidefumi Kusuda; Hisao Sato; Chitoshi Kawaguchi; Yusuke Ninomiya; Sadayoshi Nakatsukasa; Toshihiro Fujii
Original assignee: Nippon Paint Co., Ltd.; Hayakawa Rubber Co. Ltd.
Priority date: 1992-02-06
Filing date: 1993-02-05
Publication date: 1993-08-19
Also published as: JPH05216225A

Abstract

To provide a photosensitive composition which can yield a flexographic plate material having good properties as a plate material and a good solvent ink resistance at a high productivity. A photosensitive composition for flexographic plate material comprising: (1) 5-98 wt.% of a photopolymerizable composite rubber having a gel fraction of 0.5 % or less, prepared by reacting; (a) a photopolymerizable diene/urethane-modified acrylate represented by general formula (1), wherein R represents C2-C8 alkylene or polyoxyalkylene; R1 represents H or CH3; R2 and R3 represent each the residue of a diisocyanate compound; R4 represents the residue of a dihydric alcohol having a molecular weight of 2,000 or less and represented by general formula (2), (wherein R5 represents C2-C8 alkylene or polyoxyalkylene, and R6 and R7 represent each H, CH3, (meth)acryloyloxy or allyloxy); X represents a non-hydroxylated part of a liquid hydroxylated diene rubber; l represents an integer of 1 to 4; 1 < m « 4; and n represents an integer of 1 to 16, with (b) a diene elastomer of which at least one Tg is 0 °C or below; (2) 1-80 wt.% of an elastomer other than component (1); (3) 1-50 wt.% of a polymerizable compound having at least one photopolymerizable group in its molecule; and (4) 0.1-20 wt.% of a photopolymerization initiator.

Description

Incense

Photosensitive composition for flexographic plate material

'' Field of Invention

The present invention relates to a photosensitive composition for a flexographic plate material and a flexographic plate material obtained therefrom.

Conventional technology

Since the flexographic printing plate requires flexibility as the name implies, a rubber component is compounded together with the polymerizable monomer as a resin composition for the printing plate. For example, U.S. Pat.No. 3,674,486 and U.S. Pat.No. 4,332,636 and Japanese Patent 1,004,932 have an elastomeric block copolymer as a rubber component. A photosensitive flexographic printing plate material is disclosed. However, since the elastomer itself does not cross-link at the time of photocuring, the resulting plate material has poor solvent resistance.

Japanese Patent Application Laid-Open Nos. Sho 62-165643 and Japanese Patent Application No. 2-208131 disclose a photopolymerizable oligomer for improving the crosslinkability of the composition and the above-mentioned elastomer component. Have been proposed. However, the compatibility between the oligomer and the rubber may be insufficient, and the resulting plate material becomes opaque and image reproducibility decreases. In addition, although the physical properties and chemical resistance are improved by the cross-linking of the oligomer, the solvent resistance of the obtained printing plate is still insufficient. Solvent ink resistance of the obtained plate material is still insufficient. In particular, when a solvent-type flexo ink having an alcohol content of 60% or less is used, the plate material swells due to the contained solvent, and good print quality cannot be obtained with a mouth lip. In addition, there is a practical problem that the relief is rubbed (scratched) due to contact with the plate material on the upper surface when removing the inner plate from the stacked plates when handling the plate material. Purpose of the invention

Therefore, it is easy to manufacture flexographic printing plate materials, and the obtained printing plate materials have good physical properties, in particular, excellent scratch resistance of the printing plate surface and good solvent resistance (especially that of flexographic inks with low alcohol-based solvent content). There is a need for a photosensitive composition for a material and a flexographic plate material obtained therefrom.

Summary of the Invention

That is, the present invention relates to (l) (a)

General formula 1 1 II 11 III! II I 1 I ^m '

R, 0 O H H O O H H O

[However, in the formula, R is an alkylene group or a polyoxyalkylene group having 2 to 8 carbon atoms, is H or CH ₃ group, and R ₂ and R ₃ are a part obtained by removing a dicocyanate group from a diisocyanate compound, and R ₄ is a molecular weight. The following general formula 1 below 2000 2 ―

HO— F —OH… ②

R 7

(R ₅ is an alkylene group having 2-8 carbon atoms in the formula, and polyoxyalkylene groups, R _e and R ₇ are H, CH _3, or (meth) § methacryloyl Ruo Kin group, certain stomach Ariruokishi group X) is a residue excluding the hydroxyl group of the dihydric alcohol represented by the following formula, X is a portion of the diene liquid rubber having a hydroxyl group, excluding the hydroxyl group, is an integer of 1 to 4, 1 m 4, n is 1 to: I indicates an integer of 6)

And photopolymerizable gen-based urethane-modified acrylate

— One 5 to 98% by weight of a photopolymerizable composite rubber (composite composite rubber) having a gel fraction of 0.5% or less, each of which is obtained by reacting with a gen-based elastomer having a temperature of o ° c or less.

(2) 1 to 80% by weight of an elastomer other than the component (1),

(3) a polymerizable compound having at least one or more photopolymerizable groups in the molecule 1 to 50% by weight, and

(4) A photopolymerization initiator relates to a photosensitive composition for flexographic printing plate materials containing 0.1 to 20% by weight.

Detailed description of the invention

It is a well-known phenomenon that high-temperature, high-pressure, high-shear kneading of gen-based compounds, especially rubber, etc., causes polymerization and gelation. This is generally due to the fact that during the kneading process, heat causes a reaction between unsaturated bonds to cause intermolecular cross-linking, the high shear force of the gen-yarn compound itself causes physical molecular breakage at low temperatures, and chemical breakage at high temperatures. Radicals are generated by chemical molecular cleavage, and the active sites of these molecules cause the molecules to react again and form new intermolecular cross-links, resulting in compound compounding, polymerization and gelation. However, the mechanism is not yet clear.

In the present invention, by utilizing this phenomenon, a photopolymerizable gen-based urethane-modified acrylate (a) represented by the general formula (1) is reacted with a gen-based elastomer (b) and further a liquid rubber (c). It has been found that the resulting photopolymerizable composite rubber (or simply the composite rubber) has extremely excellent manufacturability, image quality, printing plate physical properties, and chemical resistance as a binder resin for flexographic printing plate materials.

The compounded rubber shown in the present invention is a compounded rubber having a new function, and is obtained by simply mixing components (a) and (b), and furthermore, component (c) as conventionally performed. Flexographic plates consisting of uncomposited compositions are not It has excellent performance and its manufacture is relatively easy.

The characteristics of this rubber compounding reaction are as follows.

(1) A photopolymerizable rubber in which a photopolymerizable group is introduced into a polymer rubber molecule can be produced. (2) Since the reaction is carried out without using a solvent in the form of a rubber solution, a dissolving or desolvating agent can be used. It is a simple process that does not require a process. (3) The complexing reaction must be performed while controlling the gelling reaction. (4) The resulting photopolymerizable composite rubber is Even afterwards, since it has sufficient photopolymerizability, it has the characteristic of giving a plate with excellent physical properties and chemical properties when used for flexographic plate materials.

The photopolymerizable gen-based urethane-modified acrylate oligomer (photopolymerizable oligomer) component (a) used in the present invention is represented by the general formula (1). The photopolymerizable oligomer is obtained mainly by reacting a gen-based liquid rubber having a hydroxyl group, an ethylenically unsaturated monomer having a monovalent hydroxyl group, a dihydric alcohol and a diisocyanate compound. It is something that can be done.

Examples of the gen-based liquid rubber having a hydroxyl group include, for example, 1.2-polybutadiene, 1,4-polybutadiene, 1,2-pentadiene, polyisoprene, chloroprene, styrene-butadiene copolymer having a hydroxyl group in the molecule, There are acrylonitrile-butadiene copolymer and the like, and these can be used alone or in combination. The number average molecular weight of the polymer of the gen-based liquid rubber having a hydroxyl group is from 1000 to 100,000, and the hydroxyl valence in the molecule (is 1 <m≤4. The crosslink density is low, the solid state maintainability of the photocured product is not satisfied, and if m> 4, the composition becomes too hard and the elasticity is reduced, so that the desired rubber elasticity cannot be obtained.

Examples of the above-mentioned ethylenically unsaturated monomers having a monovalent hydroxyl group include 2-hydroxyhexyl acrylate and 2-hydroxyxethyl methacrylate. And 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and polypropylene glycol mono (meth) acrylate, and at least one of these can be used.

Examples of the diisocyanate compound include, for example, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and methylene bis (4-cyclohexyl isocyanate), trimethylhexamethylene diisocyanate and the like. At least one compound is compounded in an amount of 5 to 190 parts by weight based on 10 parts by weight of the liquid rubber.

Further, the above dihydric alcohol has the following general formula:

R ₅

H O-R s-O H… ②

(In the formula, R ₅ represents an alkylene group having 2 to 8 carbon atoms and a polyoxyalkylene group, and R ₆ and R ₇ represent H, CH ₃ , or (meth) acryloyloxy group or aryloxy group)

And a dihydric alcohol having a skeleton represented by R in the above formula 及び and a dihydric alcohol having a photopolymerizable ethylenically unsaturated group can be used. Examples of the dihydric alcohol of the above formula (1) include, for example, ethylene glycol, ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1.3-butanediol, and 1,4-butanediol. , 1,5-pentanediol, 1,6-hexanediol, and the like. Further, examples of the dihydric alcohol having a photopolymerizable ethylenically unsaturated group include trimethylolpropane monoacrylate, trimethylolprono, Monomethacrylate, glycerol α-monoallyl ether and the like. At least one of these dihydric alcohols can be used. The blending ratio of the above components is as follows. Assuming that the repeating unit of the urethane bond is n, the molecular weight is not more than 2000 with respect to 1 mol of a gen-based liquid rubber having a hydroxyl group valence of m (1 14;) in one molecule. Preferably, the dihydric alcohol having a molecular weight of 300 or less is mx n mol, the diisocyanate compound is nx (n + 1) mol, and the monohydric ethylenically unsaturated monomer having a hydroxyl group is mmol.

Here, n is the number of repeating units of a urethane bond consisting of a diisocyanate compound and a divalent alcohol having a molecular weight of 2000 or less, and represents an integer of 1 to 16, preferably 2 to 16, and the number of repeating units is When n> 16 or n = 1, the rubber-like properties are lost, which is not preferable. The n part means the length of the part forming the hard segment with respect to the rubber molecular chain (soft segment). The long hard segment is formed of a series of urethane bonds having high polarity and cohesion, and causes microscopic phase separation with a rubber molecule chain (soft segment) having low polarity and cohesion. In addition, a dense crosslink is provided between the photopolymerizable ethylenically unsaturated groups following the hard segment. Therefore, the photopolymerizable gen-based urethane-modified acrylate used in the present invention or the photopolymerizable oligomer alone can give a high-strength, high-elongation photocured product by irradiation with an active energy ray. When a dihydric alcohol containing R ₄ having a molecular weight of 2000 or more is used, phase separation between the hard segment and the soft segment becomes difficult to occur, and the desired purpose cannot be achieved, and therefore, R ₄ is contained. The molecular weight of the dihydric alcohol is preferably 2000 or less, particularly preferably 300 or less. Such a dihydric alcohol having a molecular weight of 2000 or less is introduced into the skeleton of the hard segment component.

The photopolymerizable oligomer includes a hard segment composed of a repeating urethane bond formed from the above formula (1) and a diisocyanate compound, and a soft segment composed of the X part of the above formula (1), that is, a skeleton of a gen-based liquid rubber. of It consists of two segments.

The synthesis of the photopolymerizable oligomer will be specifically described. In an appropriately selected solvent, dibutyltin dilaurate, tin octoate, triethylamine, and triethylenediamine are added to a diisocyanate compound [πχ (η + 1)] mole. A small amount of a dihydric alcohol (nixn) having a molecular weight of 2,000 or less is added and reacted in the presence of a catalyst such as min to obtain a compound having isocyanate groups at both ends. The reaction temperature in this case is 10-120, preferably 40-80. Should be C. Next, to the compound, a mole of an ethylenically unsaturated monomer having a monovalent hydroxyl group is gradually added and reacted to obtain a compound having an isocyanate group at one terminal, and then a divalent hydroxyl group is added thereto. 1 mol of the gen-based liquid rubber is gradually added. Hydroquinone, t-butylcatechol, 0-dinitrophenol, m-dinitrophenol, p-ditrophenol, 2,4-dinitrophenol are used in this synthesis reaction as necessary to suppress thermal polymerization. , 2,4,6-trinitrophenol, methquinone, methoxyphenol, p-benzoquinone, phenothiazine, anthraquinone, 2.6-di-tert-butyl-p-cresol, etc. However, 0.05 to 1% by weight of the total compounding weight may be added, or air may be bubbled during the reaction. Thus, a photopolymerizable oligomer represented by the above formula (1) having a rubber skeleton structure and having an acryloyloxy group, a methacryloyloxy group or a mixture thereof can be synthesized.

The gen-based elastomer (b) in which at least one Tg compounded in the composition for a photosensitive flexographic printing plate material of the present invention has a conjugated genomonomeric content of at least 30 ° C. or less in one molecule is used. (Preferably at least 40%), a molecular weight of 5,000 to 1,000,000 (preferably 10,000 to 500,000) and at least one glass transition.

-?- The transfer temperature is 0 or lower (preferably 15 ° C or lower, most preferably −30; or lower). When the conjugated diene monomer unit is small, the elasticity, flexibility, image quality and the like of the obtained composition are reduced. Further, even if the molecular weight is small or large, it is not possible to obtain a film having sufficient developability and image quality. Typical elastomers include, for example, polymers of conjugated gen-based compounds and copolymers of conjugated or conjugated gen-based compounds with monoolefinic unsaturated compounds. These are prepared according to polymerization techniques known to those skilled in the art.

An elastomer having at least one Tg of less than or equal to o ° c refers to an elastomer having at least one Tg below 0 °, and includes one Tg such as a general elastomer. And that is o. c) or less, 2) Includes thermoplastic elastomers that have two or more Tg, one of which is 0 ° C or less and the other is 0 or more. The Tg of the elastomer varies depending on the measurement method, but can be easily determined by the DSC method, the TMA method, the DMA method, the viscoelasticity measurement method, or the like.

Examples of the conjugated diene compound used for the preparation of the elastomer (b) include butadiene, isoprene, and chloroprene. One or more of these may be used. Examples of the monoolefinic unsaturated compound include styrene, -methylstyrene, 0-methylstyrene, in-methylstyrene, p-methylstyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, methacrylamide, vinyl acetate, Examples include acrylates and methacrylates. In the combination of a conjugated gen-based compound and a monoolefin-unsaturated compound, one having a block copolymer structure is desirable.

Specific examples of the gen-based elastomer (b) in which at least one of the Tg is 0 ° C. or lower include a butadiene polymer, an isoprene polymer, Natural rubber, 1,2-boributadiene rubber, butyl rubber, pentadiene rubber, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-chloroprene copolymer, acryl nitrile-butadiene copolymer, acryloni Tris-isoprene copolymer, acrylonitrile-chloroprene copolymer, methyl methacrylate butadiene copolymer, methyl methacrylate isoprene copolymer, methyl methacrylate-chloroprene copolymer, methyl butyl acrylate Copolymer, methyl acrylate-isoprene copolymer, methyl acrylate-chloroprene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-isoprene-styrene copolymer, acrylonitrile-chloroprene-styrene copolymer Copolymers, and diblock copolymers such as polystyrene-polyisoprene, polystyrene-polybutadiene, polyisoprene-polybutadiene, polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-polyethylene-polystyrene, polystyrene-borate Examples include block copolymers such as styrene / butylene-polystyrene and the like, and at least one of these may be used.

The two components described above are mixed with a gen-based liquid rubber (c) as necessary, and a compounding reaction is carried out under conditions that do not cause gelation. Examples of the diene-based liquid rubber (c) include polyisoprene, 1,2-polybutadiene, 1,4-polybutadiene, 1,2-1 pentadiene, ethylene-butadiene copolymer, acrylonitrile-tagenecopoly-1, and modified products thereof. At least one compound selected from the group consisting of a liquid at room temperature and having a molecular weight of 500 to 2000 is exemplified.

In the complexing reaction, the gel fraction is controlled to 0.5% or less, preferably 0.2% or less by reacting under conditions where gelation does not occur. Gel fraction Is measured by the following method. After dissolving the composite rubber in an organic solvent, for example, a solvent such as toluene-xylene, and dissolving with stirring for 24 hours, the dissolved solution was filtered through a mesh of about 400 mesh, and the resin that could not be removed was filtered. The gel fraction is collected, sufficiently washed and dried to obtain a gelled product, and the gel fraction can be determined from the ratio to the original rubber. According to the above measurement method, the gel fraction may be substantially 0 in some cases. According to the present invention, conditions under which complexation occurs but three-dimensional cross-linking does not occur are merely expressed in terms of gel fraction, and a desirable condition of substantially zero can be naturally included. If the gel fraction is larger than 0.5%, it will be difficult to handle when used as a resin for flexographic plate materials, it will be difficult to develop and dissolve, and the target plate material performance will not be obtained. Cause problems.

The conditions under which gelation does not occur, that is, the conditions under which the gel fraction of the obtained composite product is 0.5% or less, may be performed under any conditions. For example, the reaction may be performed at a low temperature for a long time so that the reaction can be controlled. Generally, such a condition is satisfied by reacting at a temperature of 100 to ^{200 and} a pressure of 5 to 200 kg / cm ² in the presence of a gelling inhibitor. I can do it.

Examples of typical anti-gelling agents include amines (for example, naphthylamine, diphenylamine, phenylenediamine, etc.), quinoline (for example, a polymer of 2,2.4-trimethyl-1,2-dihydroquinoline, 6 —Ethoxy-1,2,2,4-trimethyl-1,2-dihydroquinoline, etc., hydroquinone derivatives (eg, 2,5-di (t-amyl) hydroquinone, 2,5-di-t-butylhydroquinone, hydroquinone monomethyl ether Etc.), monophenols (eg, 1-hydroxy-13-methyl-4-isopropylbenzene, 2,6-dibutyl phenol), bis-1, tris, or triphenols (eg, 2, 2 ' Ethylene-bis-1-methyl-6-t-butylphenol), 2,2-methylenebis (4-methyl-16-cyclohexylphenol), etc. Obisphenols (for example, 4,4'-thiobis (6-t-butyl-3.3-methylphenol)), hindered phenols, phosphites, ditroso, aniline point of 40 to 9 Examples include a naphthenic process oil containing a naphthene component at 5 ° C as a main component, a coumarone indene resin, a rosin resin, a phenol resin, and a petroleum hydrocarbon resin. These anti-gelling agents are generally known as anti-aging agents, and are listed in “Rubber Rubber Plastic E-Chemicals (Latest Version)”, Rubber Dignist Co., Ltd., published March 30, 1989. Pp. 68-127 and 481-484.

The temperature of the internal reactant is raised to 100 to 200 ° C while the frictional heat is generated by mixing and kneading the above-described raw materials and simultaneously using a heating device, and the pressure applied to the internal reactant is increased by 5 ° C. At the same time, the machine is set and operated so that the shearing force acts as a high shearing force on the reactant in the working section of the rotary kneading device while adjusting to ~ 20 O kg / cin ² to perform the compounding reaction. The complexing reaction is usually carried out by a kneader such as a hot roll, a pressure kneader, an extruder, a planetary mixer, a Banbury mixer and a mixer. In order for the applied shear force to effectively contribute to kneading and reaction, a closed kneader is particularly suitable.

The most important reaction conditions are temperature control and internal pressure control. As for the temperature, it is necessary to employ a kneading method and apparatus in which the content reactants have a uniform temperature distribution. It is thought that the conjugation reaction is mainly caused by the reaction between gen bonds between molecules. The reaction temperature is 110 to 200, preferably 100 to 180 ° 0; and more preferably 100 to 150. Below this temperature, the complexing reaction is difficult to occur, and above this temperature, it is difficult to control the complexing reaction, and the required photopolymerizable gen-urethane-modified acrylate (a) shown in ① and Tg Small In addition to the complexing reaction with at least one gen-based elastomer (b) at 0 ° C or lower, a cross-linking reaction between gen-based elastomers (b) and within the elastomer occurs mainly, and the entire rubber However, there is a risk that the polymer may become too high to handle as a polymer for flexographic printing plate material, or the whole may be gelled.

Another control factor is the control of the pressure on the internal reactants. It is necessary to adjust the pressure to 5 to 200 kg / cm ² , preferably 15 to 200 kg / cm ² , more preferably 30 to 190 kg / cm ² . In order to efficiently react the photopolymerizable gen-based urethane-modified acrylate (a) with the gen-based elastomer (1), it is necessary to make the components uniformly and well compatible with each other and to make the reaction sites close to each other. When these (a) and (b) have different viscosities or have insufficient compatibility, it is difficult to achieve a sufficiently uniform state by the ordinary kneading method. A raised closed kneader is preferably used.

Sufficient kneading is required to increase the reactivity of complexing the internal reactants. Below these pressures, the compounding reaction is insufficient, and the resulting photopolymerizable compounded rubber has poor crosslinking reactivity and physical properties. Above these pressures, a gelling reaction other than the required complexing reaction is likely to occur, and the temperature distribution and the like in the system become non-uniform, causing the entire body to gel, and In some cases, it is difficult to handle as a polymer for lithographic printing plate materials, or the desired plate material performance cannot be obtained.

The degree of the reaction of the composite reaction product of the present invention can also be confirmed by measuring the molecular weight and viscosity of the obtained rubber.

When measuring the molecular weight, the reactants are dissolved in an organic solvent before the complexation reaction, and the molecular weight and molecular weight distribution are measured by gel permeation chromatography (GPC). Photopolymerizable gen-based urethane modified resin In the acrylate (a) and high molecular weight regions, peaks due to the gen-based elastomer (b) are observed. On the other hand, after the conjugation reaction, the peak of (a) disappears, so that the conjugation of the oligomer to the rubber can be confirmed. As the photopolymerizable composite rubber for the flexographic printing plate material, one having the peak (a) disappeared and having a gel fraction of 0 is preferable. Of course, in this case, since the rubber after the complexing reaction has photopolymerizability, it is expected that the complexing is easily caused only by the reaction between the gen bonds. In this method, even if the initial gelation of the composite rubber is progressing, the degree of gelation can be easily predicted from the increase in the high molecular weight portion of the composite rubber.

The viscosity is determined by measuring the resin viscosity with a viscometer, such as a M-212 viscometer or a flow tester. However, from a practical point of view, as a monitoring method in the compounding reaction, a method of reading a change in the current value of the kneading drive section flowing into the kneader is preferable.

To promote the complexing reaction effectively, a mastication accelerator or a peptizer may be added. The compounding reaction can be facilitated by enhancing the effect of mastication and obtaining the effect of the mastication solution. There is a peptizer that is effective at both high temperature and high temperature, and it is possible to add sulphide or aromatic sulfur compounds such as 2-benzamide thiophenol for low-temperature use, and lysyl mercaptan for high-temperature use. . In order to improve the physical properties and processability of rubber and facilitate the compounding reaction, tackifiers such as alkylphenol formaldehyde resins and modified resins thereof, alkylphenol acetylene resins, cumarone Indene resin, xylene formaldehyde resin, petroleum hydrocarbon resin, polybutene, hydrogenated rosin, and processed products thereof may be combined. Further, in order to increase the stability of the polymer in the complexing reaction, a ρ-phenylenediamine compound, a fuynol compound, a paraffinic compound or the like may be added. In the present invention, another elastomer (2) is compounded as a binder in addition to the composite rubber. Such elastomers have a molecular weight of 1000 to 1, 000, 0000, preferably 50,000 to 500, 000. Further, at least one of these elastomers has a glass transition temperature of at most 110, preferably at most 130 ° C. In addition, in terms of the relationship with the composite rubber (elastomer) of (1), it is necessary to have good compatibility with them. Good compatibility includes not only the fact that the appearance does not cause turbidity due to mixing, but also the good physical performance of a film. Specific examples of such an elastomer component (2) include butadiene polymer, isoprene polymer, chlorobrene polymer, styrene butadiene copolymer, styrene-isoprene copolymer, styrene-chloroprene copolymer, Acrylonitrile-butadiene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile-chlorobrene copolymer, methyl methacrylate butadiene copolymer, methyl methacrylate-isoprene copolymer, methyl methacrylate-chloroprene copolymer, Methyl butadiene acrylate copolymer, methyl acrylate-isoprene copolymer, methyl acrylate-chloroprene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-isoprene-styrene copolymer, a Libronitrile monochloroprene-styrene copolymer, polystyrene monopolyisoprene, polystyrene polybutadiene, polyisoprene polybutadiene, and other dibutene copolymers; polystyrene monopolybutadiene polystyrene; polystyrene monopolyisoprene polystyrene; Block copolymers such as polystyrene-polyethylene-butylene-polystyrene, etc .; epichlorohydrin polymer; epichlorohydrin-ethylene oxide copolymer; epichlorohydrin-propylene oxide copolymer; And conjugated hydrocarbons such as picrohydrin rubber, chlorinated polyethylene, vinyl chloride copolymer, vinylidene chloride, polypropylene chloride, and chlorinated ethylene-propylene rubber, which are copolymers of acrylic glycidyl ether with them. Polymers. The composition of the present invention further contains a polymerizable compound (3) having at least one or more photopolymerizable groups (addition polymerizable groups) in the molecule.

Examples of the polymerizable compound (3) having at least one addition-polymerizable group in the molecule include a carboxyl group ゃ sulfone group-containing monomer: (meth) acrylic acid, styrene-p-sulfonic acid, Hydroxyl group-containing monomers; for example, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, aryl alcohol , Methallyl alcohol, N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide, o-, m-, p-hydroxystyrene, 0-, m-, p-hydroxyphenyl Two acrylates or one methacrylate, alkyl acrylate Or methacrylate; for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, propyl (meth) acrylate, acyl (meth) acrylate, cyclohexyl (meth) acrylate, o Cutyl acrylate, 2-chloroethyl acrylate, polymerizable amide; for example, acrylamide, methylarylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethyl Acrylamide, N-hexyl acrylamide, N-cyclohexyl acrylamide, N-hydroxyshethyl acrylamide, N-phenyl acrylamide, N-ditrophenyl acrylamide, N —Ethyl-N-phenylacrylamide Acrylamide or methacrylamides, nitrogen-containing alkyl acrylates or methacrylates; for example, dimethylaminoethyl acrylate, dimethylaminoethyl medacrylate, vinyl ethers: for example, ethyl vinyl ether, 2-chloroethyl Vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, vinyl ether, vinyl esters; for example, vinyl acetate, vinyl acetate, vinyl butyrate, vinyl benzoate, styrenes For example, styrene, -methylstyrene, methylstyrene, chloromethylstyrene, vinylketones: for example, methylvinyloketone, ethylvinylketone, propylvinylketo Phenylvinyl ketone, olefins; for example, ethylene, propylene, isobutylene, glycidyl (meth) acrylate, polymerizable nitrile: for example, atarilonitrile, methacrylonitrile, N-vinylpyrrolidone, N-vinylcarbazole, 4-vinyl pyridine, zwitterionic monomer; for example, Ν, Ν-dimethyl-1-Ν-methacryloxyshethyl-1- ((3-sulfopropyl) ammonium betaine, Ν, Ν-dimethyl-1-Ν — Reacts chemically with methacrylamide propyl mono- (3-sulfoprovir) -ammonium-betaine, 1- (3-sulfop-open pill) -1-2-vinylpyridinium-betaine, and any of the above monomers A compound obtained by reacting a compound having a functional group; for example, the above-mentioned hydroxyl group-containing monomer and isocyanate The reaction product monomer with bets compound, the reaction product monomers and carboxyl group-containing monomer and a glycidyl group-containing compounds.

Examples of compounds having at least two groups capable of addition polymerization include trimethylolpropane di (meth) acrylate, trimethylolpropanetri

(Meth) acrylate, divinylbenzene, ethylene glycol di (meth) acrylate Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexadiol di (meth) acrylate, triethylene glycol di (meth) acrylate Acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol di (meth) acrylate Acrylate, glycerol aryloxydi (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate Glycerol tripropoxytri (meth) acrylate, glycerol (poly) propoxytri (meth) acrylate, neopentyl glycol (poly) ethoxydi (meth) acrylate, trimethylolpropane (poly) ethoxytri (meth) acrylate, 1 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,1,1 trishydroxymethylethanedi (meth) acrylate, 1,1.1-trishydroxymethyl Ethanetri (meth) acrylate, 1,1,1 trishydroxymethylpropane di (meth) acrylate, 1,1,1,1 trishydroxymethylpropane tri (meth) acrylate, triallyl diannulate, tri Allyl isocyanurate, triaryl trimellitate , Xia Lil terephthalate, di § Lil phthalate. Preferred examples of the above are glycerol tripropoxytri (meth) acrylate, glycerol (poly) propoxytri (meth) acrylate, neopentyl glycol (poly) ethoxydi (meth) acrylate, trimethylolpropane ( Poly) ethoxytri (meth) acrylate and the like. The photopolymerizable initiator (4) is a compound having a function of initiating addition polymerization by light irradiation. Examples of such a compound include benzoin ethers (for example, benzoin isopropyl ether, benzoin isobutyl). Benzophenones (eg, benzophenone, methyl-10-benzoinbenzoate, 4,4'-bis (dimethylamino) -benzophenone), xanthones (eg, xanthone, thioxanthone, 2-cloxantoxanthone), Acetofphenones (eg, acetofphenone, trichloroacetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-1-2-funyulasetofenone), benzyl, 2-ethylanthraquinone, methylbenzoylformate, 2-hydroxy- 2-Methylpropionpheno And 2-hydroxy-2-methyl-4'-isopropyl-isopropiophenone, 1-hydroxycyclohexylphenol ketone and the like. These may be used alone or in combination.

The photosensitive resin composition of the present invention may also optionally contain conventional additives, for example, a heating weight of 0.001% to 2.0% based on the weight of the total photosensitive resin composition without solvent. Inhibitors can be included. Suitable polymerization inhibitors include, for example, hydroquinone, hydroquinone monomethyl ether, mono-t-butyl hydroquinone, catechol, p-t-butyl catechol, 2,6-di-t-butyl-p-cresol, benzoquinone, 2, 5-diphenyl p-benzoquinone, p-methoxyphenol, t-butyl pyrocatechol, pyrogallol,

—Naphthol, 2,6-di-tert-butyl-p-cresol, phenothiazine, pyridine, nitrobenzene, dinitrobenzene, the nitrosonimer inhibitor system described in UK Patent No. 1,453,681. And the bis (substituted amino) sulfides disclosed in US Pat. No. 4,168,981. Other useful polymerization inhibitors include p-toluquinone, chlorani And thiazine dyes such as thionine blue G (CI 52025), methylene blue B (CI 52015) and toluidine blue (CI 52 040). Preferred inhibitors are 2.6-di-tert-butyl-4-methylphenol and p-methoxyphenol.

The photosensitive resin composition of the present invention is further improved by incorporating an appropriate amount of a well-known well-compatible antioxidant and / or antiozonant in order to prevent polymerization inhibition by oxygen, ozone, and the like. be able to. Antioxidants useful in the present invention include alkylated phenols, such as 2,6-di-t-butyl-4-methylphenol, alkylated bisphenols, such as 2.2-methylenebis (4-methyl-6-t-butylphenol), 3,5-trimethyl-2,4,6-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2--4-hydroxy-3,5-di-tert-butylanilino-1,6-bis (n —S-octylthio) -1,3,5-triazine, polymerized trimethyldihydroquinone and dilaurylthiodibutone pionate. Examples of the antiozonants useful in the present invention include microcrystalline wax and paraffin wax, dibutylthiourea, 1,1.3,3-tetramethyl-2-thiourea, “antisozonant” AFD (a product of Naphton), norbornane, and 5-Norbornene 2-methyl adipate, G 5-Nonorne Bornene 2-methyl maleate, G 5-Norbornene 2-methyl terephthalate, Ozone Protector 80 (a product of Reichhold Chemical Co.), N-Fuji Lu 2-naphthylamine, unsaturated vegetable oils (eg, rapeseed oil, linseed oil, safflower oil), polymers and resins (eg, ethylene / vinyl acetate copolymer resin, chlorinated polyethylene, chlorosulfonated polyethylene, chlorine) Chemical modified Tylene / methacrylic acid copolymer, polyurethane, polypropylene Nantagen, polybutadiene, furfural derived resin, ethylene / Propylene / diene rubber, diethylene dalicol ester of rosin, and α-methylstyrene Z-vinyl toluene copolymer).

Optionally, the photosensitive resin composition also includes an immiscible polymeric or non-polymeric organic or essentially non-scattering actinic radiation that is essentially transparent at the wavelengths used to expose the photosensitive resinous material. Incorporation of inorganic fillers or scavengers, such as polystyrene, internally three-dimensional microresin particles (microgels), organophilic silica, bentonite, silica, powdered glass, colloidal carbon, and various types of dyes and pigments Can be. Such materials are used in various amounts depending on the desired properties of the elastomeric composition. Fillers improve the strength of the elastic layer, reduce tack (stickiness), and are also useful as colorants.

If desired, a plasticizer having good compatibility may be used in the photosensitive resin layer to lower the glass transition temperature of the binder and facilitate selective development. The plasticizer must be compatible with the polymer. Among the common plasticizers that can be used are dialkyl phthalates, alkyl phosphates, polyethylene glycols, polyethylene glycol esters and polyethylene glycol ethers.

In the resin photosensitive composition for flexographic printing plate material of the present invention, the composite rubber (1) is 5 to 98% by weight, preferably 10 to 95% by weight, more preferably 15 to 90% by weight, 1 to 80% by weight, preferably 5 to 50% by weight, more preferably 5 to 30% by weight of the elastomer (2) other than the component (1), and 1 to 50% by weight of the polymerizable compound (3). %, Preferably 2 to 40% by weight, more preferably 5 to 25% by weight, and the photoinitiator (4) is 0.1 to 20% by weight, 0.1 to 10% by weight, more preferably 0.2 to 5% by weight (when the total composition is 100%). The composite rubber (1) is less than the above range! The physical properties of the plate material cannot be obtained, and the printability cannot be obtained. If the amount is larger than the above range, the developability is reduced. If the amount of the elastomer component (2) other than the component (1) is less than 1% by weight, the balance between the developability and the physical properties of the plate material is difficult, and it is difficult to manufacture the plate material. If the amount is more than 80% by weight, sufficient physical properties of the plate material cannot be obtained, and the printability is not satisfied. If the content of component (3) is less than 1% by weight, sufficient image quality cannot be obtained. If it exceeds 50% by weight, the plate will lack elasticity and will not be suitable for flexographic printing. If the amount of the photopolymerization initiator is less than 0.1% by weight, sufficient image quality cannot be obtained and the sensitivity is lowered. If it exceeds 20% by weight, the crosslink density and the hardness of the plate will increase, making it unsuitable for flexographic printing.

The above-described photosensitive resin composition of the present invention can be used for producing a resin plate for flexographic printing. That is, the resin for flexographic printing of the present invention is obtained by subjecting the photosensitive resin composition obtained above to a suitable state (for example, sheet or blade) in a molten state by a conventional method, for example, extrusion molding or extrusion molding. It is obtained by calender molding on a support material to a thickness of 200 to 2 Omm. Examples of the support material include a plastic plate, a plastic sheet, a rubber sheet, a foamed olefin sheet, a foamed rubber sheet, a foamed urethane sheet, a metal plate, and a metal sheet. A resin plate for flexographic printing can be obtained by appropriately applying an adhesive to these supports as required. Usually, a mat layer is formed on these flexographic printing resin plates in order to improve the vacuum adhesion of the negative during exposure and to enhance the peelability of the negative film after exposure. Therefore, as a desirable structure, the above-mentioned photosensitive resin composition of the present invention is formed on a flexible support via an adhesive layer, and further has a flexible mat thereon. In the production of the flexographic printing plate of the present invention, for example, first, the resin for flexographic printing obtained as described above is exposed through a negative film having an appropriate image to cause photopolymerization on the exposed portion. To get a latent image. As light used for exposure, For example, ultraviolet light is used. Next, after exposure, a non-exposed portion is developed with a developer and washed away to obtain a relief image. If this is further dried and post-exposed with ultraviolet light, the flexographic printing plate of the present invention having excellent image reproducibility, water resistance, rubber elasticity and mechanical strength can be obtained. The flexographic printing plate is particularly suitable for commercial flexographic printing because of its excellent developability and durability. In addition, the ozone resistance of the manufactured flexographic printing plate can also be improved by annealing it at high temperature before use.

The invention's effect

In the present invention, physical properties as a flexographic plate material are obtained by using a photopolymerizable composite rubber, that is, a composite rubber obtained by subjecting a gen-based urethane-modified acrylate having a photopolymerizable functional group to a conjugated reaction with a gen-based rubber. And chemical properties, especially the solvent resistance and the ink resistance of flexo solvent inks with low alcohol content are improved. It is also easy to form a flexographic plate material.

Example

The present invention will be described in more detail by way of examples. The present invention is not limited to these examples.

Synthesis example 1

Production of photopolymerizable gen-based urethane-modified atalylate

2,4-Tolylene diisocyanate (hereinafter abbreviated as “TDI”) A solution of 48.4 g in dioxane 14.5.2 g is placed in a 50-mL reaction vessel and placed under a nitrogen atmosphere. While stirring with, a solution prepared by dissolving 16.6 g of 1,4-butanediol, 0.2 g of quinone at the opening and 0.2 g of triethylenediamine in 49.8 g of dioxane was added dropwise. The temperature of the reaction solution was maintained at 75 to 80 ° C, and the reaction was continued at the same temperature for 2 hours after the completion of the dropwise addition. Next, 10.8 g of 2-hydroxyshethyl methacrylate (hereinafter abbreviated as “H EMA”) was dissolved in 32.4 g of dioxane. The solution was added to the reactor and reacted at 75 to 80 ° C for 2 hours with stirring in a nitrogen atmosphere.

Further, a solution prepared by dissolving 100 g of liquid rubber (JSR-HTPB (manufactured by Nippon Synthetic Rubber Co., Ltd., average molecular weight: 2120, hydroxyl group content: 0.93)) in 300 g of dioxane was put into another 1000 ml reactor and stirred with nitrogen. The above reactants were added dropwise under stirring. During the dropwise addition, the reaction solution was kept at 75-80, and after the completion of the dropwise addition, the reaction was continued at the same temperature for 6 hours. The infrared absorption spectrum was used to confirm that the absorption of the isocyanate group (225 Ocir ¹ ) had disappeared. Finished. The reaction solution was pale yellow and transparent and had a viscosity of 450 cps (30 BH type viscometer).

The reaction solution was gradually dropped into a beaker containing 5400 ml of n-hexane to obtain a white precipitate. The sludge was dried in a vacuum drier for 2 days after removing the solvent layer by a gradient method. After drying, a solid urethane acrylate was obtained. The yield of the polymer was 162 g (92% yield). In the measurement of infrared absorption scan Bae click preparative le, in SSOOcnr ^ 292 Ocm '^ 1710cm' 1. 1640cm "1 specific absorption was observed. The molecular weight determination by Gelber permeation chromatography Chillon chromatography (G PC), the number The average molecular weight was 3400. Synthesis Examples 2 to 4

Production of photopolymerizable gen-based urethane-modified acrylate

Perethane acrylate was produced in the same manner as in Example 1 except that the types of the liquid rubber and the dihydric alcohol having a molecular weight of 2000 or less used in Synthesis Example 1 were changed. Table 1 shows the mixing ratio and the physical properties of the obtained urethane acrylate. Table 1 also shows examples of formulations in which the number n of hard segment repeating units is increased. The weight of the liquid rubber used here is 100 g. table 1

* 1) Poly bd R-45 HT Idemitsu Petrochemical Co., Ltd. Average molecule: >> 2800 hydroxyl group included 含 0.83 (meq g)

* 2) 〇 means that the characteristic absorption was observed in 330 Ocm— ', 292 Ocm—17 1 Ocm —'. 164 OcnT ',

Synthesis example 5

(Synthesis of composite rubber)

45 parts of the photopolymerizable gen-based urethane-modified acrylate obtained in Synthesis Example 1, 45 parts of a styrene-butadiene rubber having a styrene content of 23.5%, and a liquid 1,2-polybutadiene having a molecular weight of 300,100 Parts and :: One part of L-loop naphthylamine is placed in a pressurized kneader and pressurized and kneaded for 4 hours while maintaining the temperature in the system at 130 to 140 ° C. A complexing reaction was performed while performing the reaction. During the complexing reaction, the current flowing through the pressurized kneader and the temperature inside the system were continuously monitored. During the conjugation reaction, the current value remained constant without any decrease. On the way, sampling was performed at the second hour. The molecular weight distribution of the photopolymerizable composite rubber obtained after the complexation reaction was analyzed using GPC at 1, 1 and 2 hours. After the reaction, Mn = 72.000 and Mw-116,000. Some peaks attributable to the gen-based urethane-modified acrylate observed before the start of the conjugation reaction were partially observed at the second hour, but disappeared after the reaction. Next, 1 part of the composite rubber was taken, dissolved in 19 parts of toluene over 24 hours, and then filtered through a 400 mesh screen to measure the gel fraction. It was 0.1% after the reaction and 0.1% after the reaction.

Gel fraction = {(filtration residue on 400 mesh) / (sample amount)} X 100

%

100 parts of the obtained composite rubber and 2 parts of irgacure (IR-1651, manufactured by Ciba-Geigy Corporation) were taken as a photopolymerization initiator, kneaded well, and the photopolymerizability was confirmed as 100 film. . I

Table 2 continued

Synthesis Example 12

A part of the composite chemical composition 11 obtained in Synthesis Example 15 was reacted in the same manner for another hour while raising the composite temperature and maintaining the temperature at 160 ° C, and the composite chemical reaction was performed. Obtained. The gel fraction of this elastomer measured by the same method was 1.0%.

Example 1 1

65 parts of the photopolymerizable composite elastomer obtained in Synthesis Example 1-5, 25 parts of a polystyrene-polyisoprene-polystyrene block copolymer elastomer (trade name: CARIFLEX TR-1107, manufactured by Shell), polyethylene glycol glycol Acrylate (obtained from polyethylene glycol with a molecular weight of 200) 4 parts, 1,6 hexanediol diacrylate 2 parts, trimethylolpropane triacrylate 2 parts, Irgacure 651 as a photopolymerization initiator (manufactured by Ciba-Geigy) 1.5 Parts, Irgacure 184 (manufactured by Ciba-Geigy Corporation), 0.5 part, methquinone 0.1 part, and G-tert-butylparacresol 2 parts were charged into a pressure kneader and stirred and mixed to obtain a photosensitive flexographic printing plate composition.

The resulting mixture is further extruded into a sheet by a 350 single-screw extruder equipped with a double-armed extruder, and is a 130-thick polyester coated with a black mouth-prene adhesive (Hitachi Chemical Co., Ltd. A 2.8 mπ photosensitive resin layer was formed on the film. Next, a PET film coated with a coating solution for forming a matting layer consisting of a toluene solution of a polyamide resin and a fine silica powder was layered thereon, and the matting layer was transferred to the plate for photosensitive flexographic printing plates. I got it.

In order to form a relief on the surface of the photosensitive flexographic printing plate, a back exposure was performed from the back of the plate using an exposing machine consisting of a 60W ultraviolet lamp. After forming the floor for a few minutes, a negative film having an appropriate image was brought into close contact with the vacuum and then irradiated for 12 minutes to perform the main exposure. After irradiation, development was carried out with 20 ml of trichlorethane for 5 minutes using a dissolution machine 1215 system manufactured by DuPont to obtain a negative 1.2 faithful relief 1.2M printing plate.

The obtained plate material has a Shore hardness A of 47 degrees, has sufficient elasticity, is strong, and has an alcohol content of 800 at a printing speed of 500 feet / minute with a stack type two-color flexographic printing press. Printing was performed on a 70-thick milk-white treated polyethylene film using flexo ink of at least%. No change was observed on the surface of the printing plate even after printing 200,000 passes.

Solvent resistance evaluation

In order to examine the solvent resistance of the obtained printing plate, the plate was immersed in hexane and ethyl acetate, allowed to stand for 6 hours, removed, and the attached solvent was removed. It was 82% for xanth and 86% for ethyl acetate.

Next, using a solvent-type flexoink with an alcohol component of 60% or less for polyfilm, a 10,000-thick milky-white polyethylene film was printed through 10,000 passes and the surface of the printing plate was observed. No change was observed on the surface of the printing plate even after printing 100,000 passes, but thin lines were slightly thicker than those at the beginning. Evaluation of film properties

A practical toughness check of the obtained printing plate was performed by a coin scratch method. Although scratching was performed five times, no scratch was found and it was confirmed that the steel had good toughness.

Comparative Example 1

In Example 11, the photopolymerizable gen-based urethane modification obtained in Synthesis Example 1 was used. Example of synthesis of a mixture of 29.3 parts of polyacrylate, styrene-containing S2 3.5% styrene-butadiene rubber with 3.5% 29.2 parts, liquid 1,2-boributadiene having a molecular weight of 3,500 A composition for photosensitive flexographic printing plate material is obtained in the same manner except that the compounding reaction is not performed instead of the compounding reaction in place of (5), and the photosensitive layer is formed by forming a resin layer on a polyester film in the same manner. A flexographic printing plate was obtained.

Exposure and development were performed in the same manner to form a relief to obtain a printing plate. The resulting plate material had a Shore hardness A of 45 degrees, and printing was performed on a 70-thick milky-white polyethylene film using a flexoink containing an alcohol component of at least 80% at a printing speed of 500 feet / minute. Although printing was performed for 100,000 copies, the fine lines of the printing plate were slightly missing.

In a similar solvent resistance test of the obtained printing plate, an increase in the weight of the plate material due to an organic solvent of 160% for hexane and 100% for ethyl acetate was observed. In a printing test using a solvent-type flexo ink of not more than 10%, thick printed thin relief lines were observed after printing 10,000 times, and good printed matter was not obtained. In addition, the toughness of the plate was similarly tested by the coin scratch method, but three out of five scratches were scratched.

Comparative Example 2

In Example 1, a composition for a photosensitive flexographic printing plate material was obtained in exactly the same manner as in Example 1, except that the one obtained in Synthesis Example 12 was used as the composite chemical elastomer, and a flexographic printing plate was similarly produced. Manufactured.

In the same manner, a relief was formed by exposure and development to obtain a flexographic printing plate, but the image reproducibility was not good. In particular, the depth at the white spots at the diameters of 250 # and 7500X was shallow, and did not have practical performance. Table 3 Example (l) I ^ LfcjEl ^ i lath-(2) Other than (1) (!) Stomach-(3) Polymerizable compound (4) Polymerization initiator (5) Others

2 Synthesis example 1 6 79 parts TR-1107 10 parts Limeci 0- * bu 0 banzofu I non 1.0 parts Mmrj 0.02 parts μ "7 k!) Rate -2 parts Zochi 7 gin 0.01 parts Kishi Ichi ft" !) Rate 2 copies

Tori I-Tylene glycol コー

, Di 7 creators' 2nd

3 Synthetic example-End part / TR-110 end 25 parts Ri 1 Tyrene glyco- »RH651 1.5 parts

S-BI5X 7- * ¹ 48 parts

Nesai Pliers Little

, Di 7 crete '3 copies

+9

4 Synthesis Example—8 65 parts / S-II Lasta 25 parts Glyce Q-Polyethylene Nzov Inon 1.0 part Pen 0.1 part

Glyco-diacrylate-4 parts [di-tert-butyl 1.6-hexanediyl-le-laqueryl 2.0 parts, diacryle- "3.0 parts

* 1 SB ester 'styrene-butadiene block copolymer elastomer with 28% styrene content * 2 SI ester styrene-containing S15% styrene-isoprene block copolymer elastomer with 28%

Examples 2 to 4

A composition for photosensitive flexographic printing plate material was obtained in the same manner with the composition shown in Table 3, and a printing plate was obtained in the same manner. Each plate had good image quality and printing performance. It also had good performance in the solvent resistance test.

Examples 5 to 8

Synthetic example of the photopolymerizable composite elastomer (1) having exactly the same composition as in Example 1 was used instead of Synthetic Example 1-5 instead of Synthetic Example 1-9, 110, -11, and 1-6. In the same manner, a composition for a photosensitive flexographic printing plate material was obtained, and a printing plate was prepared and evaluated. All had good performance.

Claims

The scope of the claims

1. (l) (a)

General formula 1

I II ^Λ II II II II II II ⁿ

R, 0 O H H O O H H O

[However, alkylene or polyoxy alkylene group R charcoal purple number 2-8 in the formula, is H or CH _3, portions R ₄ R ₂ and R ₃ excluding the Isoshianeto group from Jiisoshianeto of compound is The following general formula 1 with a molecular weight of 2000 or less 2

Re

HO- R ₅ -OH… ② R,

(R ₅ is an alkylene group having 2 to 8 carbon atoms in the formula, and polyoxyalkylene groups, R _e and R ₇ are H, CH _3, or (meth) § methacryloyl Ruo alkoxy group,. One had the Ariruokishi group X is a residue excluding the hydroxyl group of the dihydric alcohol having a hydroxyl group, X is an integer of 1 to 4, 1 is m≤4, n is The gel fraction obtained by reacting the photopolymerizable gen-based urethane-modified acrylate represented by the formula (1) with at least one of the (b) Tg and the following gen-based elastomer is 0.5 5 to 98% by weight of photopolymerizable composite rubber of

(2) Elastomers other than component (1) :! ~ 8C wt%,

(3) 1 to 50% by weight of a polymerizable compound having at least one or more photomultiplying groups in the molecule, and (4) A photosensitive composition for a flexographic printing plate material comprising 0.1 to 20% by weight of a photopolymerization initiator.

2. The reaction according to claim 1, wherein the reaction between the modified acrylate (a) and the gen-based elastomer (b) is carried out in a closed kneader at a temperature of 100 to 200 ° C in the presence of a gelling inhibitor. Photosensitive composition.

3. The photosensitive composition according to claim 1, wherein (c) a gen-based liquid rubber is added as a third component in the reaction between the modified acrylate (a) and the gen-based elastomer (b).

4. In the reaction between the modified acrylate (a) and the gen-based elastomer (b), the amount of the modified acrylate (a) is 5 to 90% by weight, and the amount of the gen-based elastomer (b) is 10 to 10%. 3. The photosensitive composition according to claim 2, wherein 70% by weight and the amount of the anti-gelling agent used are 0.01 to 5% by weight.

5. The photosensitive composition according to claim 3, wherein the amount of the gen-based liquid rubber (c) is 1 to 30% by weight.

6. Gen-based elastomers) are selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, pentadiene rubber, and block copolymers of styrene with isoprene or butadiene. The light-sensitive composition according to claim 1, wherein the composition is prepared. ·

7. (l) (a)

General formula 1

I II H i Mi II III! To ^m

R, 0 O H H O O H H O

Wherein R is an alkylene group having 2 to 8 carbon atoms or polyoxy An alkylene group, is an H or CH ₃ group, R ₂ and R ₃ are portions of the diisocyanate compound excluding the isocyanate group, and R ₄ is a compound represented by the following general formula 1 2 R _{

H O-Rs- OH… ②

[

(Wherein R ₅ is an alkylene group having 2 to 8 carbon atoms and a polyoxyalkylene group, and R ₆ and R ₇ are H, CH ₃ , or (meth) acryloyloxy group, or aryloxy group). X) is the residue excluding the hydroxyl group of the dihydric alcohol represented by the following formula: X is the part of the diene liquid rubber having a hydroxyl group excluding the hydroxyl group, is an integer of 1 to 4, 1 is πι≤4, and n is 1 to The gel fraction obtained by reacting the photopolymerizable gen-based urethane-modified acrylate represented by the formula (1) with (b) a gen-based elastomer having at least one Tg of 0 ° C or less is 0.5%. 5 to 98% by weight of the following photopolymerizable composite rubber,

(2) Elastomer other than component (1) 1-80% by weight,

(3) a polymerizable compound having at least one or more photopolymerizable groups in the molecule 1 to 50 weight, and

(4) Photosensitive composition for flexographic plate material containing 0.1 to 20% by weight of photopolymerization initiator

Is formed on a flexible support with a thickness of 200 to 2Οππη via an adhesive layer, and further has a flexible resin mat layer on the photosensitive flexographic printing plate.