WO2007072613A1

WO2007072613A1 - Elastomer constituent and photosensitive composition making use of the same

Info

Publication number: WO2007072613A1
Application number: PCT/JP2006/318236
Authority: WO
Inventors: Motokazu Takeuchi; Fumiaki Miura; Masatoshi Torii; Takumi Miyachi
Original assignee: Kraton Jsr Elastomers K.K.
Priority date: 2005-12-22
Filing date: 2006-09-14
Publication date: 2007-06-28
Also published as: JPWO2007072613A1; JP5163872B2

Abstract

An elastomer constituent that is suitable for use in a printing plate material; and a photosensitive composition making use of the elastomer constituent that excels in laser workability performance, image developability, clear printing even with respect to small letters and, with a hydrophilic polymer added thereto, water developability. There is provided an elastomer constituent comprised mainly of a block (co)polymer containing as indispensable components a polymer block composed mainly of at least two aromatic vinyl compounds, a copolymer block of specified structure consisting of a polymer block composed mainly of at least one conjugated diene and a polymer block composed mainly of one or more conjugated dienes wherein one or more aromatic vinyl compound polymer blocks may be contained. Further, there is provided a photosensitive composition comprising the above elastomer constituent, a photopolymerizable unsaturated monomer and a photopolymerization initiator.

Description

Specification

Elastomer-one composition and photosensitive composition using the same

Technical field

[0001] The present invention relates to 1) a single elastomer composition, and 2) a photosensitive composition. More specifically, an elastomer-one composition obtained by combining two types of specific conjugated diene-based block (co) polymers, and a photopolymerizable unsaturated monomer, a photopolymerization initiator, and the elastomer-one composition. The present invention relates to a photosensitive composition which is excellent in image developability, sharp printability even in small letters, and dimensional stability, and further, in the case where a hydrophilic polymer is added, in addition to water developability.

Background art

[0002] The photosensitive composition is used as a plate material for letterpress printing represented by flexo printing and letter press printing, and is widely used mainly for films, labels, envelopes, heavy bags, wrapping paper, corrugated cardboard and the like. It is done.

A thermoplastic block copolymer is mainly used as one elastomer component of the photosensitive composition, and among them, a styrene-based polymer block composed mainly of styrene and a polymer block composed mainly of butadiene or isoprene. Plasticizable elastomers (SBS, SIS) are disclosed particularly well (Patent Document 1, Patent Document 2, Patent Document 3).

As a method for obtaining a photosensitive composition, a styrene-based thermoplastic elastomer, liquid polyvinyl alcohol, a photopolymerizable monomer, a photopolymerization initiator, and a hydrophilic polymer when water developable is made at 100 ° C to 200 ° C. It is common to knead | mix with a C mixer. At that time, one of the factors for having excellent image reproducibility and having clear printability even for small characters is to suppress the gel amount of the photosensitive composition and to have low hardness and high strength.

[0003] The control of the amount of gel includes (1) prevention of thermal deterioration during kneading, (2) management of gel amount in raw materials, etc. For (1), appropriate adjustment of kneading temperature and anti-aging agent It corresponds by optimizing the amount of antioxidants).

In addition, (2) is dealt with by managing the amount of gel derived from the raw material. Of the raw materials, the one that most affects the amount of gel is the styrenic thermoplastic elastomer It is done. Examples of using a type (SEBS, SEPS) or a partially saturated type (SBBS) of saturated double bonds of polymer block portion mainly composed of butadiene or isoprene as a measure for reducing gel amount are disclosed. Speak! (Patent Document 4).

In the case of the saturated type, the co-crosslinking property of the styrene-based thermoplastic elastomer with the photopolymerizable monomer by the photopolymerization initiator is inferior and preferable.

Further, it is not preferable because the rate of light curing which is considered to be compounded to an appropriate amount or more of the amount of an antioxidant (antioxidant) in the styrenic thermoplastic elastomer is decreased, and the material cost is further increased.

It is possible to cope with low hardness and high strength by changing the molecular design of styrenic thermoplastic elastomer which is one component of elastomer used (Patent Document 5, Patent Document 6), but In order to achieve this, it is necessary to add a large amount of liquid polymer, and there is a problem that the material cost is greatly increased.

Patent Document 1: Japanese Patent Application Laid-Open No. 5-94015

Patent Document 2: Japanese Patent Application Laid-Open No. 2003-280186

Patent Document 3: Japanese Patent Application Laid-Open No. 5-134425

Patent Document 4: Japanese Patent Application Laid-Open No. 9-40728

Patent Document 5: JP-A-5-134410

Patent Document 6: Japanese Patent Application Laid-Open No. 2000-181060

Disclosure of the invention

Problem that invention tries to solve

The present invention relates to an elastomer composition suitable for a printing plate material having a specific conjugated diene block (co) polymer as a main component, a laser processing characteristic using the elastomer composition, an image development It is an object of the present invention to provide a photosensitive composition which is excellent in water resistance, printability even in small letters, and water developability when a hydrophilic polymer is added.

Means to solve the problem

[0005] As a result of intensive studies to develop a photosensitive composition having the above-mentioned performance, the present inventors have found that the gel amount is small in a specific range of structure! / ヽ aromatic vinyl compound Block copolymers with conjugated gen show very good performance and this purpose is achieved The present invention has been completed.

The present invention relates to (a) a polymer block composed mainly of at least two aromatic bi-loi-blends and a polymer block copolymer composed mainly of at least one conjugated agent, And 20 to 40% of the total bonded aromatic vinyl compound content in the block copolymer, and 10 to 50% of the boule bond content in the polymer block mainly composed of a conjugated gene. And a block copolymer having a peak molecular weight of 70,000 to 300,000 in terms of standard polystyrene measured by gel permeation chromatography (GPC) (hereinafter also referred to as "(a) block copolymer"), (B) A block (co) polymer which essentially comprises a polymer block mainly composed of one or more conjugated dienes and which may contain this and one or more aromatic vinyl copolymer polymers block, And the total bond viscosity of the block (co) polymer Aromatic vinyl compound content: SO to 25%, vinyl bond content in polymer block mainly composed of conjugated gen: 10 to 80%, standard poly determined by gel permeation chromatography (GPC) Block (co) polymers having a styrene-equivalent peak molecular weight of 5,000 or more and less than 70,000 and (a) less than 1Z3 of the peak molecular weight of the block copolymer (hereinafter referred to as “(i) pro The present invention also relates to an elastomer composition comprising (1) / (i) (weight ratio) = 60 to 95Z5 to 40).

Here, one constituent of the elastomer of the present invention is

(I) 20 to 80% of the vinyl bond content in the copolymer block mainly composed of the conjugated diene of the block (co) polymer is preferably 30 to 80%. Also, (() Mel 卜レレレレ (190. C, 2 1 2 N) force ^). 1 to 20 g Z 1 o minutes,

(E) Toluene insoluble content is 20 ppm or less, and

(E) Hardness measurement method according to JIS K6253 Type A hardness is 30 to 70, and

(Force) an antiblocking agent is contained in an amount of not more than 0.2 parts by weight with respect to 100 parts by weight of the elastomer-constituting member,

Is preferred.

Furthermore, in the elastomer single composition of the present invention, the content of the total amount of the bonded aromatic vinyl compound in the (a) block copolymer is 20 to 35%, and gel permeation chromatography of the copolymer is also carried out. The peak molecular weight in terms of standard polystyrene measured by (GPC) is 100, Forced to be between 000 and 250,000!

Furthermore, in the elastomer single composition of the present invention, the peak molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC) of the (i) block (co) polymer is 10,000 to 50, It is 000!

Next, the present invention

Said (k) Elastomer one component,

(G) photopolymerizable unsaturated monomers, and

(F) Photopolymerization initiator,

It relates to the photosensitivity characterized by containing.

Here, the blending proportions of the respective components in the photosensitive composition of the present invention are 10) to 90% by weight of the (i) elastomer composition and 1 to 50% by weight of (g) the photopolymerizable unsaturated monomer. And (f) The photopolymerization initiator is 0.010 to L0% by weight (wherein (f) + (f) + (f) = 100% by weight). In the photosensitive composition of the present invention, (co) liquid polybutadiene can further be contained.

In this case, the blending amount of (co) liquid polybutadiene is 50% by weight or less in the photosensitive composition.

Furthermore, the photosensitive composition of the present invention may further contain a (j) hydrophilic polymer.

In this case, the blending amount of the (h) hydrophilic polymer is 5 to 80 wt% in the photosensitive composition.

Effect of the invention

The elastomer composition of the present invention is suitable as an elastomer component of a printing plate material for relief printing represented by flexo printing and letter press printing.

Further, the photosensitive composition of the present invention is hydrophilic if the elastomer composition of the present invention, the photopolymerizable unsaturated monomer, the photopolymerization initiator and, if necessary, liquid polybutadiene and water developability are required. It is a composition with water soluble polymer, has good laser processability, image developability, sharp printability even for small letters, excellent water developability when hydrophilic polymer is added, and photosensitivity for flexo plate Photosensitive combination usable for resin, photosensitive resin for letterpress etc It is a product.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

First, an elastomer construction of the present invention will be described.

The elastomer composition used in the present invention comprises (a) a polymer block mainly composed of at least two aromatic vinyl compound and a polymer block mainly composed of at least one conjugated agent. Block copolymer, and (i) a polymer block mainly composed of one or more conjugated dienes, and a block which may contain the block and one or more aromatic bi-lodine compound polymer blocks The (co) polymer is a main component.

Here, as the aromatic vinyl ethylene compound used to obtain the (a) to (i) components, styrene, t-butynostyrene, a-methinolestyrene, p-methinolestyrene, dibibi And 1, 1-diphenylenostyrene, N, N dimethi nol p amino ethynole styrene, N, N jetyl p-aminoethyl styrene, buryl pyridine, etc., and particularly styrene, a-methyl styrene And p-methylstyrene is preferred.

In addition, as conjugated dienes used to obtain components (a) to (i), 1,3 butadiene, isoprene, 1,3 pentagen, 2-methyl 1,3 pentagen, 1,3 Examples of these include Sagen, 4,5 Jetyl-1, 3-Octagen, 3Butyl-1, 3-Octadiene, and Croupprene, but 1,3-butadiene, isoprene and 1, 3-pentadiene are preferred, with 1, being preferred. 3 Butadiene, isoprene.

Here, the content of the aromatic boule compound of the (a) block copolymer is 20% by weight to 40% by weight, preferably 20% by weight to 35% by weight. If the content is less than 20% by weight, the photosensitive composition of the present invention has low plate strength after exposure to a flexographic printing plate or a letterpress printing plate, and defects in the plate material during the washing-out step or excessive Sharp printing can not be performed when printing pressure is strong. On the other hand, if it exceeds 40% by weight, the flexibility of the printing material is poor, which is not preferable because it causes blur and printing unevenness.

The content of the aromatic vinyl compound of the (i) block (co) polymer is 0 wt% to 25 wt%, preferably 0 wt% to 20 wt%. If this content exceeds 25% by weight, the flexibility of the printing material is poor, which is not preferable because it causes blurring and printing unevenness. Also, the boule bond content in the (a) block copolymer is 10% to 50%, preferably 10% to 30%. If this content is less than 10%, industrial production is difficult. On the other hand, if it exceeds 50%, in the photosensitive composition of the present invention, after exposure, the plate strength is low when it is used as a flexographic printing plate or letterpress printing plate; You can not make a sharp mark j if you use it.

Further, the boule bond content of the (i) block (co) polymer is 10% to 80%, preferably 20%.

% To 80%. If this content is less than 10% or more than 80%, industrial production is difficult. In the photosensitive composition of the present invention, when it is converted to a flexographic printing plate or a letterpress printing plate after exposure, in order to obtain sharp printing, the vinyl bond content of (i) block (co) polymer is Is more preferably 30 to 80%.

Furthermore, the peak molecular weight in the (a) block copolymer is 70,000 to 300,000, preferably 100,000 to 250,000 in terms of standard polystyrene measured by gel permeation chromatography (GPC). It is. Less than 70,000, photosensitive photosensitive yarn composition of the present invention 【After exposure to light, the plate strength of the flexographic printing plate and the letterpress printing plate is too low. Sharp printing can not be performed when defects or excessive printing pressure is applied. On the other hand, if it exceeds 300,000, the miscibility with the photopolymerizable unsaturated monomer used in the photosensitive composition of the present invention is poor, which is preferable.

In the present invention, “peak molecular weight” refers to the molecular weight of the peak tip (peak of peak), and the same applies to the following.

(Ii) The peak molecular weight of the block (co) polymer is 5,000 or more and less than 70,000 in terms of standard polystyrene measured by gel permeation chromatography (GPC), and A) The peak molecular weight in the block copolymer is less than 1Z3, preferably less than 1Z5. (B) If the molecular weight of the component is less than 5,000, it is unrealistic in terms of economics. Further, when the molecular weight of the (i) component is 70,000 or more, or 1Z3 or more of the peak molecular weight of the (a) component, the flexibility is inferior or the processability at the time of producing the photosensitive composition is inferior.

(I) The peak molecular weight in the block (co) polymer is preferably 10,000 to 50,000, more preferably in terms of standard polystyrene measured by gel permeation chromatography (GPC). <Is 10,000-40,000. If it is less than 10,000, the photosensitive composition of the present invention In addition, after exposure, the plate strength is low when it is used as a flexographic printing plate or a letterpress printing plate, and sharp defects can not be obtained if defects in the plate material or excessive printing pressure occurs during the washing process. Absent. On the other hand, when it exceeds 50,000, it is inferior to the processability at the time of producing a photosensitive composition.

The ratio of (a) block copolymer to (i) block (co) polymer is (a) / (i) (weight ratio) = 60 to 95Z5 to 40, preferably 70 to 95Z5 to 35, More preferably, it is 75 to 95, 5 to 30. (A) When the block copolymer content is less than 60% by weight, in the photosensitive composition of the present invention, after exposure, the plate strength is low when forming a flexographic printing plate or a letterpress printing plate. Sharp printing can not be performed when material defects or excessive printing pressure is strong. On the other hand, if it exceeds 95% by weight, the processability at the time of producing a photosensitive composition is inferior.

The polymer block mainly composed of the conjugated diene in (a) block copolymer and (ii) block (co) polymer may contain an aromatic vinyl compound. . The structure may be random or incremental taper blocks. As a random and taper analysis method, a method by GPC of decomposition products obtained by ozone cleaving all double bonds of butadiene units by Tanaka et al. (“Rubber Chemical Technology”, No. 59, p. 16, 1986) And the acid decomposition method using osmium tetraoxide and t-butyl hydroxide peroxide ("Journalist's polymer" science, 1st page, page 429, 1946). A polymer block mainly composed of an aromatic vinyl compound and a polymer block mainly composed of a conjugated gene are adjusted by containing a bonded aromatic vinyl compound in a polymer block mainly composed of a conjugated gene Thus, the miscibility with the photopolymerizable unsaturated monomer used in the photosensitive composition of the present invention is improved. The amount of the conjugated aromatic vinyl compound in the polymer block mainly composed of the conjugated diene is 30% by weight or less, and when it exceeds 30% by weight, the molecular weight of the polymer block mainly composed of the aromatic vinyl compound is small If the photosensitive composition is used as a photosensitive composition, the plate strength of the flexographic printing plate and the letterpress printing plate after exposure is too low. It is not preferable because sharp printing can not be performed. The structure containing the aromatic vinyl compound may be a random structure or a tapered block in which the aromatic vinyl compound gradually increases.

[0020] The melt flow rate (190 ° C, 21.2 N) of one elastomer component of the present invention is preferred. Or 0.5 to 20 g Z10, more preferably 0.5 to 8 g Z10. When the amount is less than 1 lgZlO, the photosensitive composition has poor image compatibility with the photopolymerizable unsaturated monomer and the photopolymerization initiator, and when the water developability is required, the compatibility with the hydrophilic polymer is poor. And unfavorably cause deterioration of plate strength. On the other hand, if it exceeds 20 gZlO, the plate strength is low and it is not preferable. In the elastomer single-piece construction of the present invention, the melt flow rate can be adjusted, for example, by the amount of the polymerization initiator.

Further, the (f) toluene insoluble content of one elastomer component is preferably 20 ppm or less, more preferably 15 ppm or less, particularly preferably 10 ppm or less. When the toluene insoluble content exceeds 20 ppm, in the photosensitive composition of the present invention, it is not preferable because it causes defects of the printing plate during the washing step and sharpness of small characters during printing. Here, the toluene insoluble content is a value measured by the method described later. The toluene insolubles can be easily adjusted by mild or rapid conditions for dissolution.

Furthermore, the hardness measurement method according to JIS K6253 (A) of the elastomer single body preferably has a hardness of 30 to 70, and more preferably 35 to 70. If it exceeds 70, it is not preferable because it has poor flexibility and causes blurring and printing unevenness. On the other hand, if it is less than 30, the plate strength is low when it is made a flexo printing plate or a letterpress printing plate after exposure, and sharp printing can not be performed if defects in the printing plate or excessive printing pressure occurs during the washing step. . The hardness can be easily adjusted by the total bonding content of the aromatic vinyl compound.

It is to be noted that (a) block copolymer and (i) block (co) polymer used for one elastomer component of the present invention, and further, one elastomer component of the present invention containing these as a main component It may be in the form of pellet, porous pellet or crumb.

In order to produce an elastomer composition of the present invention, (a) block copolymer, and (ii) block (co) polymer are dissolved in a hydrocarbon solvent using an organic lithium compound as an initiator and then added to the solution. It is preferable to obtain the respective polymer solutions obtained by legally mixing them separately, mixing and homogenizing the obtained respective polymer solutions and then removing them by dissolving. For example, after producing the (a) block copolymer as described above, the above (i) block (co) polymer solution may be further mixed with solution, homogenized, and then dissolved. it can.

Here, the (i) component can be finished separately using a special manufacturing method, but (a) In production facilities generally used for block copolymers etc., substantial production can not be achieved due to problems of stickiness and drying defects. In addition, even special equipment is not suitable for mass production, and it can not be denied that it is cost-wise disadvantageous. Therefore, mixing with the component (a) may be followed by homogenization followed by dissolution and drying. It is preferable practically.

Also, the (i) block (co) polymer may be polymerized simultaneously with the polymerization of the (a) block copolymer described above to produce an elastomer single-piece construction of the present invention. For example, in order to produce (a) a block copolymer as the first step, an aromatic vinyl compound and a polymerization initiator (initiator 1) are brought into contact and reacted, and then a conjugated gene is added, After the reaction is completed, a polymerization initiator (initiator-2) is added, and a conjugated diene is added again, and (a) block (co) polymer is continued while (b) block copolymer production is continued. Start production of Finally, an aromatic vinyl compound may be reacted to simultaneously produce (a) a block copolymer and (b) a block (co) polymer to make a single elastomer. Here, in order to control the molecular structure of the polymer to be produced, the addition of the second stage initiator is preferably after the completion of the polymerization of the first stage conjugated gen, but the amount of the conjugated gen addition of the first stage is adjusted. However, it may be added in the middle of the polymerization, and the addition of the second stage coagent may be omitted. Also, in order to precisely control the molecular structure of the polymer to be produced, the addition amounts of the first and second stage initiators, and the addition amounts of the first stage aromatic vinyl copolymer and the conjugated diene And, it can be carried out by adjusting the amount of addition of conjugated ben and aromatic burle compound in the second stage.

Specific examples of the method for producing the (a) block copolymer or (i) block (co) polymer used in the present invention include, for example, organic lithium compounds and the like in an inert hydrocarbon solvent. It can be produced by sequentially polymerizing an aromatic vinyl compound and a conjugated gene, which is used as a polymerization initiator.

For example, it can be produced by first polymerizing an aromatic vinyl compound and then polymerizing a conjugated diene, then reacting a coupling agent or again reacting an aromatic vinyl compound. In addition, in polymerization of a conjugated diene, a desired amount of an aromatic bi-Louisium compound may be added and copolymerized, if necessary. Preferably, the production method does not use a coupling agent. When a coupling agent is used, the transparency of the coupling agent is deteriorated due to the residue of the coupling agent, which affects the developability. [0027] As the above-mentioned inert hydrocarbon solvent, hydrocarbons such as pentane, n-hexane, heptane, octane, methylcyclopentane, cyclohexane, benzene, xylene and the like can be used. Xane is preferred.

As an organic alkali metal compound which is a polymerization initiator, an organic lithium compound is preferable. As this organic lithium compound, organic monolithium, organic dilithium and organic lithium compound are used.

Specific examples thereof include ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, isoprenyldilithium and the like, and the amount of 0.02 to 2 parts by weight per 100 parts by weight of the monomer. Used in

Also, at this time, as a regulator of microstructure, ie, content of buryl bond of conjugated gen moiety, a Lewis base such as ether, amine and the like, specifically jetyl ether, tetrahydrofuran, propyl ether, butyl ether, Higher ether, ethylene glycolomethylethione ethylene glycol, ethylene glycolo regethinole tenolee, ethylene glycolo regethinole tenolee, ethylene glycolo resin dibutyle nore tenolee, propylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethyleneglycolo dibutyl ether nore tenolee Ether derivatives of polyethylene glycol such as ethylene glycono rebutinore tenore ethylene glycono resibut no ester, tetramethyl as amine Ji Renjiamin, pyridine, tertiary Amin such Toripuchiruamin and the like, used in conjunction with an inert hydrocarbon solvent.

These can also be used as a structure regulator of the aromatic vinyl compound Z conjugated gen when copolymerizing the aromatic vinyl compound in the polymerization of a polymer block mainly composed of a conjugated diene!

[0029] The polymerization reaction is usually carried out at 20 to 120 ° C, preferably 30 to 100 ° C. Also, even if polymerization is carried out under control at a constant temperature, it may be carried out under elevated temperature without heat removal.

A bifunctional coupling agent is preferably used as a coupling agent which may be used for the production of (a) block copolymer and (i) block (co) polymer. As such, for example, dibromomethane, dibromoethane, dibromopropane, methylene chloride , Dihalogenated alkanes such as dichloroethane, dichloropropane, dichlorobutane, dichlorosilane, methyldichlorosilane, dimethyldichlorosilane, monoethyldichlorosilane, getyldichlorosilane, monobutyldichlorosilane, dibutyldichlorosilane, monohexyl dichlorosilane Halogenated compounds such as chlorosilanes, dihexyldichlorosilanes, dibutary mosilanes, monomethyl dibutary mosilans, dimethyl dibutary mosilanes, diaromatic bee compounds such as dibuylbenzenes and dibuernaphthalenes, cetyl formate, ethyl acetate, Ester compounds such as butyl acetate, methyl propionate, phenyl acetate, ethyl benzoate, phenyl benzoate, and diethyl ether adipate, sulfur compounds such as dibutyl dichloro tin and tetrachloro tin, bis pheno R 1 A, Bisphenol 1 AD, Bisphenol 1 F, 3-glycidoxypropyltrimethoxysilane, other epoxy compounds, propyuric acid chloride, acid chloride such as dihydroxy acid dichloride, 1, 4- Chloromethylbenzene, tolylene diisocyanate and the like can be mentioned.

Further, the bonding content of the aromatic vinyl compound of the (a) to (i) components is controlled by the supply amount of the monomer at the time of polymerization in each stage, and it is controlled as needed. The binding content is adjusted by varying the components of the microregulator. In addition, the structure of a conjugated vinyl-based polymer block of an aromatic vinyl complex, Z conjugated, is also controlled by the above-mentioned microregulator. Here, the structural control of the aromatic vinyl compound Z-conjugated agent is to control the bonding state of the random, tapered or block structure of the aromatic vinyl compound bonded to the conjugated agent.

Further, the weight average molecular weight and melt flow rate of the (a) to (i) components are adjusted by the addition amount of a polymerization initiator, for example, sec-butyllithium.

Further, an elastomer composition having (a) a block copolymer and (b) a block (co) polymer as main components can be obtained by the following method after polymerization according to the above method. .

For example, the polymer solution is poured into hot water with stirring, the solvent is distilled off, the water-containing polymer is dewatered with a screw-type squeezer, acetone or alcohol is coated and precipitated, and the method is dried with a band dryer. And direct solvent removal using an extruder. Preferably, the method is charged into hot water with stirring, the solvent is distilled off, and the water-containing polymer is dewatered with a screw-type squeezer. The dewatered one elastomer composition of the present invention may block by its own weight.

(Force) The antiblocking agent may be added in an amount of 0.2 parts by weight or less in terms of 100 parts by weight of one elastomer. When it exceeds 0.2 parts by weight, the image developability of the photosensitive composition of the present invention and the clear printability of even small characters are inferior. Preferred antiblocking agents are inorganic substances such as silica, talc and calcium stearate, and metal soaps. The blocking inhibitor preferably has an average particle size of 30 m or less, and more preferably 1 to 20 μm, as measured by Coulter Counter 1 method.

Next, the photosensitive composition of the present invention is a photosensitive composition obtained by blending the above-mentioned (k) one elastomer component with (g) a photopolymerizable unsaturated monomer and (k) a photopolymerization initiator. It is a composition.

In the photosensitive composition of the present invention, when the blending amount is too small, the (i) elastomer composition is inferior in flexibility and lacks sharpness in small characters. On the other hand, if it is too large, the image developability is poor. Accordingly, the (i) one component of the elastomer is preferably 10 to 90% by weight, more preferably 50 to 90% by weight, based on the total amount of the photosensitive composition.

The photopolymerizable unsaturated monomer (g) used in the photosensitive composition is an unsaturated compound having a photopolymerizable ethylenic double bond, and a general photosensitive elastomer composition. As long as it can be used for products and photosensitive resin compositions, it can be used without particular limitation. Specifically, ethylene glycol mono (meth) atalylate, diethylene glycol mono (meth) atalylate, propylene glycol mono (meth) atalylate, polyethylene glycol mono (meth) atalylate, polypropylene glycol mono (meth) atarilate , Polyethylene glycol monomethoxy monoazatalylate, N-methylol acrylamide, N-ethyrol acrylamide, N-propyrrole acrylamide, N-methylol (meth) acrylamide, N-ethylol (meth) acrylamide, N-propyrrole methacrylamide, Diacetone acrylamide, hydroxypropyl atalylate, triacryl formal, diacrylamide dimethylene ether, methylene bis acrylamide, ethylene glycol di (Meth) atalylate, diethylene glycol di (meth) atalylate, triethylene glycol di (meth) atalylate, tetraethylene glycol di (meth) atalylate, polyethylene glycol di (meth) atalylate, trimethylolpropane tri (meth) Atalylate, trimethylol propane di (meth) atalylate, oligourethane di (meth) atalylate, 1, 3-butanedio Di- (meth) atalylate, 1, 4-butanediol di (meth) atalylate, 1, 6 hexandiol di (meth) atalylate, glycerin di (meth) atalylate, neopentyl diaryl di (meth) atalylate, 1, 10-decanediol di (meth) atalylate, ethylene oxide adduct of bis phenol A di (meth) atalylate, ethylene oxide modified trimethylol propane triarylate, pentaerythritol tetra (meth) atalylate, pentaerythritol triol (Meth) atarylates, triacrylic formals, methacrylamides, styrenes, butyltoluenes, diarylbenzenes, diaryl phthalates, triaryl cyanurates, fumaric acid getil esters, fumaric acid dibutyl esters, fumaric acid dioxtyl esters , Fumaric acid distearyl ester, fumaric acid butyloctyl ester, fumaric acid diaryl ester, fumaric acid dibenzyl ester, maleic acid dibutyl ester, maleic acid dioctyyl ester, fumaric acid bis (3-phenylpropyl) ester , Fumaric acid dilauryl ester, fumaric acid diperyl ester, N-n-hexyl maleimide, N-cyclohexyl maleimide, N-n-octyl maleimide, N- 2-ethyl hexyl maleimide, N- n-decyl maleimide And N-n-laurylmaleimide.

These photopolymerizable unsaturated monomers may be used alone or in combination of two or more.

[0035] When the content of the photopolymerizable unsaturated monomer is too small, the formation of fine dots and characters is reduced. On the other hand, if the blending amount is too large, the hardness of the obtained plate becomes high and the ink riding becomes worse. The amount of the photopolymerizable unsaturated monomer is preferably 1 to 50% by weight, more preferably 1 to 20% by weight, based on the total amount of the photosensitive composition.

Further, the photopolymerization initiator (f) used for the photosensitive composition is particularly limited as long as it can be used for general photosensitive elastomer compositions and photosensitive resin compositions. It can be used without any problems. For example, benzophenones, benzoins, acetifephenones, a-diketones, acyloines, acyloin ethers, benzyl alkyl ketals, polynuclear quinones, thioxanthones, glycyl phosphines, etc. are specifically mentioned. Benzophenone, Chlorbenzophenone, Acetophenone, Benzyl, Diacetyl, Benzoin, Viva in, Benzoin methyl ether, Benzoin ethyl ether, Benzoin isopropyl ether, Benzoin butyl ether, Hydroquinone monomethyl ether, Benzyl dimethyl ketal, benziljetil ketal , Benzyl diisopropyl Examples include luketal, anthraquinone, 2-acetylanthraquinone, 1,4-naphthoquinone, methylnaphthoquinone, 2-chloroanthraquinone, thioxanthone, 2-chlorothioxanthone, and acyl phosphine oxide.

These photopolymerization initiators may be used alone or in combination of two or more.

If the blending amount of the photopolymerization initiator is too small, the photopolymerization initiation ability tends to be insufficient. If the blending amount is too large, the inside of the photosensitive composition does not cure due to light shielding by itself. Development makes it easy to lose images. The blending amount of the photopolymerization initiator is preferably 0.1 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total amount of the photosensitive composition.

[0038] A (co) liquid polybutadiene can be further blended into the photosensitive composition of the present invention. Here, the liquid polybutadiene is a liquid polybutadiene at a normal temperature (23 ° C.) having a weight average molecular weight in terms of polystyrene of about 100 to 20,000, preferably about 500 to 10,000.

By blending (co) liquid polybutadiene with the photosensitive composition of the present invention, the sheet processability at plate making, plate strength after exposure, and plate strength and balance when made into a flexographic printing plate and a letterpress printing plate are good. It produces acupuncture effect.

The blending amount of (co) liquid polybutadiene used in the photosensitive composition is preferably 0 to 50% by weight, more preferably 5 to 40% by weight, based on the total amount of the photosensitive composition. If more than 50 by weight ^_0/0, sharp when after exposure, flexographic printing plate, defects and excessive printing pressure plate strength is Teigu washout process when plate material when the letterpress printing plate did not force Unable to print.

Furthermore, the photosensitive composition of the present invention can be made water-developable by incorporating a (j) hydrophilic polymer. The hydrophilic polymer used in the photosensitive composition requiring water developability is water or a developer containing an aqueous alkaline solution, an aqueous acidic solution, an organic solvent, or a surfactant containing water or water as a main component. It means a polymer that is soluble or swelled (dispersed), COOM group [carboxylic acid (metal) base], SO M group [sulfonic acid (metal)

3

Base] (M represents a hydrogen atom, periodic table group I, Π, a group III element, an amine, an ammonium) It is a polymer having a hydrophilic group such as NH 2 or -OH and having no crosslinking. .

2

Examples of such hydrophilic polymers include polyvinyl alcohol (PVA), carboxyme In addition to general-purpose resins such as chill cellulose, gen-based rubbers obtained by copolymerizing (meth) acrylic acid and a mixture of jenny, liquid polybutadiene modified with maleic anhydride, and COOM group (MOM as an especially effective skeleton) the I, [pi, III group element is a hydrogen atom, the periodic table, Amin, § Nmo - © shows the beam) to 50 to 50, 000 is equivalent ZL0 ⁶ g with polymer, the periodic table I, as a II group element And alkali metals such as sodium, potassium and lithium, alkaline earth metals such as calcium and magnesium, boron and aluminum. In the present invention, the COOM group 50 equivalent ZL0 less than ⁶ g, poor affinity for water, while it is difficult tool developed with neutral water 50, 000 exceeds the equivalent ZL0 ⁶ g, resistance to aqueous ink resistance Because it is inferior, it is desirable.

Specific examples of the hydrophilic polymer include COOM group-containing polyurethane, -COOM group-containing polyester, COOM group-containing epoxy compound, COOM group-containing polyamic acid, -COOM group-containing acrylonitrile-butadiene copolymer, -COOM group Containing styrene-butadiene polymer, COOM group-containing polybutadiene, polybutyl alcohol (PVA), polyacrylamide, sodium polyacrylate, carboxymethylcellulose (CMC), hydroxyl cellulose (MRC), methylcellulose (MC), polyethylene glycol For example, hydroxide, polyethyleneimine, and the compound derivative may be used, but not limited thereto.

The compound used to neutralize at least a part of the carboxyl group contained in the above-mentioned hydrophilic polymer includes hydroxides of alkali metals such as sodium hydroxide, carbonates and the like. Alkali metal carbonates such as lithium, potassium carbonate and sodium carbonate, hydroxides of alkali metals such as potassium tetrabutoxide and sodium methoxide, hydroxides of polyvalent metals such as calcium hydroxide, magnesium hydroxide and aluminum hydroxide , Polyvalent metal alkoxides such as aluminum isopropoxide, tertiary amine such as tolylamine, tri-n-propylamine, secondary amine such as jetlyamine, di-n-propylamine, n-propylamine, etc. Primary amines, cyclic amines such as morpholine, N, N Examples include amino group-containing (meth) atalylate such as noethyl (meth) atalylate, N, N dimethylaminoethyl (meth) atalylate, ammonium salts such as ammonium carbonate and the like. These may be used alone or in combination of two or more.

The above-mentioned hydrophilic polymer may have a polyoxyalkylene chain as a hydrophilic portion in addition to the COOM group, and may have an ethylenically unsaturated group so as to act as a crosslinking agent. May be In the present invention, as the hydrophilic polymer, in addition to the above hydrophilic polymer, for example, a polymer having a hydrophilic group such as a hydroxyl group, an amine group or a sulfonic acid group and z or a polyoxyalkylene chain may be used in combination. .

The amount of the (h) hydrophilic polymer in the photosensitive composition of the present invention is preferably 5 to 80% by weight in consideration of water-based developability and water-resistant ink resistance when water developability is required. More preferably, it is 7 to 40% by weight. If the amount is less than 5% by weight, the water developability is inferior. If the amount is more than 80% by weight, the flexibility is inferior to cause blur and printing unevenness, which is not preferable.

In addition to the above-described essential components, the photosensitive composition of the present invention may optionally contain various auxiliary additives such as plasticizers, fillers such as calcium carbonate, other thermoplastic polymers, Antioxidants, pigments, crosslinkers, flame retardants, UV absorbers, antihalation agents, light stabilizers and the like can be added. The compounding amount of these auxiliary additive components is 5% by weight or less in the photosensitive composition of the present invention.

Among these, as plasticizers, hydrocarbon oils such as naphthenic oil and paraffin oil, liquid polystyrene, modified products of liquid polybutadiene, liquid acrylonitrile / butadiene copolymer, liquid styrene / butadiene copolymer, number average molecular weight 2 And polystyrenes, sebacates, phthalates and so on.

Further, as other thermoplastic polymers, other styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene-block copolymer, other thermoplastic elastomers, liquid rubber, thermoplastic resin, For example, other polymers such as styrene-butadiene rubber latex, ethylene-acetate-cobalt copolymer, ethylene-ethyl acetate copolymer, atactic polypropylene, syndiotactic 1,2-polybutadiene, ethylene propylene rubber and the like can be mentioned. In this case, the components (a) to (i) of the present invention and the other thermoplastic polymer are kneaded at an arbitrary ratio, pelletized and / or powdered. It can also be used.

[0046] Furthermore, in the photosensitive composition, as the antioxidant (antioxidant), it contains phenol. It is preferable that at least one selected from the group consisting of phosphorus compounds, phenol compounds and ratatone compounds, which does not generate any phenol after hydrolysis, is also selected. Examples of this phosphorus compound and Z or phenol compound include 2,6 di-t-butyl taresol, 4,6 bis (octylthiomethyl) -o-cresol, 1,3,5-tri-methyl-2,4,6 tris. (3,5-di-t-butyl 4-hydroxybenzyl) benzene, 2,2-methylenebis (6-t-butyl-4 methylphenol), pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionate], Octadecyl- 3-(3, 5 di-t-butyl 4-hydroxyphenyl) propionate, 2-t-butyl 6- (3-t-butyl 2-hydroxyl 5- methylbenzyl) 4- methylphenyl Atarylate, 2- [1- (2-hydroxy-3,5 di-t pentyl phenyl) hexyl] 4, 6-di-tert-pentyl phenyl arylate, 6- [3- (3-t butyl-4-hydroxy- Five- Chill) propoxy]-2, 4, 8, 10-tetra-tert-butyldibenz [d, f] [l, 3, 2] diophosphosphepin, tris (2,4-di-t-butylphenyl) phosphate, Tetrakis (2, 4 di-t-butylphenyl) [1, 1-biphenyl] — 4, 4, di-bisbisphosphite, 2, 2- methylene bis (4, 6 di-t-butyl phenyl) Octyl phosphite, reaction product of 3-hydroxy-1,5-di-tert-butyl-furan-one and o-xylene, 3-hydroxy-5,7-di-tert-butyl-furan 2-one and p-xylene Products of the reaction, products of reaction of 3-hydroxy 5, 7-di-tert-butyl-furan 2-one with m-xylene, products of reaction of 3-hydroxy 5, 7-di-tert-butyl furan 2-one with toluene, etc. .

The above-mentioned antioxidizing agent used for the photosensitive composition is preferably 0.2 to 4.0% by weight, more preferably 0.3 to 3.0% by weight, in the photosensitive composition. If the amount is less than 0.2% by weight, the amount of gel increases, which is not preferable for the sharpness of small characters. On the other hand, when it exceeds 4.0% by weight, the light curing speed is unfavorably lowered.

As an acid inhibitor other than the phenolic compound, the phosphorus compound and the ratatone compound, for example, an ionic compound may be added together. In addition, stabilizers such as light stabilizers may be added. As light stabilizers, benzotriazole-based, benzophenone-based, etc., may be used. [0048] The photosensitive composition of the present invention can be prepared by various methods. For example, the raw material to be compounded is a suitable solvent such as esters such as butyl acetate and 3-methoxybutyl acetate, petroleum fractions, hydrocarbons such as decalin and toluene, ketones such as methyl ethyl ketone and methyl isobutyl ketone , Ethers such as tetrahydrofuran, chlorforms such as chloroform, carbon tetrachloride, 1, 1, 1-trichloroethane, tetrachlorethylene, trichlorethylene, etc. and alcohols such as propanol, butanol, pentanol etc. It is possible to dissolve it in a mixed solvent and mix it, pour it into a mold, evaporate the solvent, and leave it as a plate as it is. If the plate of this photosensitive composition is heat-pressed, the layer with higher thickness accuracy can be obtained. Is obtained. In addition, after the photosensitive composition is mixed using an extruder, a mixer, a Bantry mixer or the like, it is possible to form a desired thickness by hot press molding, calendering or extrusion. The support and the flexible film layer can be adhered to the photosensitive layer by roll lamination after sheet formation. After lamination, heat pressing can be performed to obtain a photosensitive layer with high accuracy.

In the photosensitive composition of the present invention, a support such as a polyester may be provided on the opposite side of the relief in order to maintain the accuracy as a printing plate.

Further, the photosensitive composition of the present invention may be tacky depending on its composition, so in order to improve the contact with the transparent picture simple substance (negative film) to be superimposed thereon, the reuse of the image simple substance is required. In order to make it possible, a flexible film layer may be provided on the surface.

As an actinic ray source used for photocuring the photosensitive composition of the present invention, a low pressure mercury lamp, a high pressure mercury lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, a xenon lamp, a zirconium lamp, sunlight, etc. is there.

The photosensitive composition of the present invention can also be processed by a laser. A carbon dioxide gas laser can mainly be used as a laser oscillation device.

Here, the dose of the actinic radiation source is usually in the range of 10 to ³ , OOO mj Z cm ² .

After the photosensitive composition of the present invention is irradiated with an actinic ray through a transparent image carrier to form an image, a developer used to elute the unexposed area dissolves the unexposed area well. It is preferable that the image area which has been dispersed and exposed is hardly affected.

For example, in the solvent system, chlorine such as 1, 1, 1-trichloroethane, tetrachlorethylene, etc. Examples include organic solvents, esters such as butyl acetate and 3-methyloxy acetate, petroleum fractions, hydrocarbons such as toluene, and mixtures thereof with alcohols such as propanol and butanol added thereto as an example. Can.

The water system is water such as tap water, well water, industrial water and the like, and may or may not contain a surfactant.

Elution of the unexposed area is carried out by spraying with a nozzle force or by brushing with a brush.

Example

EXAMPLES The present invention will be described more specifically with reference to examples. The present invention is not limited to these examples.

In the examples, parts and% are by weight unless otherwise specified.

In addition, various evaluations in the examples are obtained as follows.

<(A) Block Copolymer, (i) Block (Co) Polymer, or a Mixture of These Also Properties of One Elastomer>

(1) Weight average molecular weight (Mw)

For measurement of weight average molecular weight, gel permeation chromatography (HLC-8220) manufactured by Higashi Soichi Co., Ltd. was used, and Ultrabondagel E750A manufactured by Waters was used as a column. Tetrahydrofuran is used as the solvent, and the measurement conditions are a temperature of 45 ° C., a flow rate of 1. Oml Z, a sample concentration of 0.1%, an injection amount of 201, and a value converted with a standard polystyrene.

(2) bound styrene content

The content of bound styrene was calculated by the absorption intensity force calibration curve method at a wavelength of 699 cm ¹ using an infrared spectrometer (Fourier transform type infrared spectrometer made by Perkin Elmer ^One ).

(3) Quantitative analysis of boule bond content in butadiene

Based on the analysis results obtained by measuring 450 to ¹ , 200 cm.sup.- ¹ obtained as described above, the boule bond content in butadiene was calculated by the Morello method.

(4) Analysis of Melt Flow Rate [MFR (D)] For this analysis, Automelt Indexer 1 (TP-404 type) manufactured by Tester Sangyo Co., Ltd. was used. The analysis sample measured the said one elastomer composition according to D method (190 degreeC, 21.2N load) of JISK7210. The unit is gZlO minutes.

(5) Toluene insolubles

After dissolving 100 g of block (co) polymer lOOg in toluene, the insoluble matter in toluene was measured by filtration through a 100 mesh wire mesh.

(6) Hardness

It was measured according to JIS K6253 using a Type A Deuterus meter.

(7) Image developability

When development was carried out according to the method described in Example 1, a non-exposed area is hardly developed and a non-exposed area is difficult to be developed, with a development depth of about 1 mm at the non-exposed area corresponding to the negative of the printed image. An image with a depth of 0.7 mm or less was X.

(8) Even small letters and clear printability

When development is carried out by the method described in Example 1, the line width corresponding to the negative of the printed image is distorted to the shape of a convex thin line of 0.1 mm width, and reproduced in the same width as the fat-free negative. In the case of てい, the shape of the convex thin line of 0.2 mm width is distorted, the case of reproducing with the same width as the negative without fat power is 〇, and the case of being reproduced substantially in the width of 0.2 mm. 、, X was not reproduced.

(9) Dimensional stability

In order to evaluate the dimensional stability of the sheet before exposure, a weight of 720 g was placed on a sheet of 3 × 3 cm in size, and the reduction (%) of plate thickness after 7 days at 40 ° C. was measured. When the plate thickness reduction rate (%) is 5% or less, it is 〇, and when it is more than 5%, it is X.

(10) Laser processability

Sealed carbon dioxide laser oscillator (USA Shinraddo Co., output; 25W) at the mounted laser processing machine [Great Computer Corporation (Great Computer Corporation), manufactured by "Laser Pro (L _ase r Pro)"), the speed ( SPEED was used as 20 (%), power (POWER) 100 (%), and resolution 1000 (dpi). Here, speed 20 (%) is 20 (%) means about 200 mm Zsec because it is a velocity and can be varied from 2.5 mm Zsec to 1066 mm Zsec. The output is variable from 0 to 100 (%) at a maximum of 25 W, and 10 0 (%) indicates 25 W.

The sheet produced in (9) was subjected to laser processing, and the flame generation during processing, the stickiness of the processed surface, and the odor were evaluated. "O" means good or none, "X" means bad or big.

Example 1

(A) block copolymers, (i) block (co) polymers, and elastomers of these properties.

After completely replacing the 100-liter stainless steel polymerization vessel with a jacket and a stirrer with nitrogen, 50 kg of cyclohexane and 0.8 kg of styrene were charged, and the contents were brought to 40 ° C. by passing warm water through the jacket.

Then, 5.Og of sec-butyllithium was added to initiate polymerization. After completion of the styrene polymerization, 6.4 kg of 1,3-butadiene was slowly added with temperature control so that the content temperature would be 80.degree. After completion of polymerization, 0.8 kg of styrene was added and reacted for 30 minutes. After the reaction, 1 ml of methanol was added, and after stirring for 10 minutes, the mixture was transferred to a blending container, and 50 g of Sumilizer 1 BHT (manufactured by Sumitomo Chemical Co., Ltd.), which is an antioxidant, Irganox B220 / FF (CHINOKU) '50g of Specialty Chemicals was added.

Furthermore, after completely replacing the 100-liter stainless steel polymerization vessel with a jacket and a stirrer with nitrogen, 15 kg of cyclohexane, 0.3 kg of styrene, and 20 g of ethylene glycol acetyl ether are charged, and the contents are passed through warm water through the jacket. The temperature was 40 ° C. Then, 1 l of sec-butyllithium was added to initiate polymerization. After completion of the styrene polymerization, 1.7 kg of 1,3-butadiene was slowly added while the temperature was adjusted so that the content temperature became 50 ° C., and the reaction was allowed to proceed for 30 minutes. After the reaction, 20 ml of methanol was added, and after stirring for 10 minutes, the mixture was transferred to a blending vessel to prepare a mixed solution.

The mixed solution was steam-stripped and the solvent was removed to obtain a water-containing crumb. Subsequently, the resultant was dewatered and dried by a heat roll, and pelletized by a 50 mm extruder, to obtain an elastomer (1). Stearic acid as an antiblocking agent to obtain A shim (Ca-St manufactured by Nitto Kasei Kogyo Co., Ltd., average particle diameter measured by Coulter Counter = 12 m) was used, and 0.1 g (PHR) added to 100 g of the elastomer (No. 1). did. Table 1 shows the analysis values and physical property values.

Examples 2 to 6

It was obtained in the same manner as in Example 1 except that the charge of styrene, 1,3-butadiene and sec-butyllithium, ethylene glycol jetyl ether as a vinyl modifier, and the amount of antiblocking agent were changed. The results are shown in Tables 1 and 2.

Example 7

of

One part of the elastomer obtained as described above (No. 1) 90 parts, 8 parts of 1, 6-hexanediarylate, 1.5 parts of 2, 2-dimethoxy-2-phenylacetophenone, 0.5 parts of 2, 6-di-t-butylcresol was kneaded at 150 ° C. in a 3 L-binder.

The obtained photosensitive composition was placed in a 3 mm-thick sheet mold, sandwiched between upper and lower 0.1 mm polyester films, heated at 130 ° C. with a press, and cooled to form a 3 mm-thick sheet. After molding, one of the polyester films is peeled off, and an exposure amount of 90 0 WZ cm ^{2 is} achieved so that the thickness of the cured layer is about 1.5 mm using an ultraviolet exposure machine (manufactured by Nippon Denshi Seiki Co., Ltd., JE-A4-SS type). Exposed for 2 minutes. Next, the polyester film on the side not exposed was peeled off, the negative film for evaluation of reproducibility was brought into close contact with the surface, and this side was exposed for 15 minutes with the same exposure amount by the above-mentioned exposure machine. The negative film was removed, and the unexposed area was dissolved away with a mixed solvent of trichloroethene Z-isopropyl alcohol (mixing ratio = 80Z20). Thereafter, it was dried at 50 ° C. for 30 minutes, and the surface from which the unexposed area was removed was re-exposed for 10 minutes at the same exposure amount with the above light source to evaluate the photosensitive characteristics. The results are shown in Table 3.

[0060] Examples 8 to 12

Ito

It was prepared and evaluated in the same manner as in Example 7. The results are shown in Tables 3 and 4.

Examples 13 to 14 Ito

A photosensitive composition was prepared in the same manner as in Example 7, except that Example 13 used an elastomer (No. 2) and Example 14 used an elastomer (No. 1). The results are shown in Table 5

Example 15

Ito

50 parts of one elastomer (no. 4) obtained above, 40 parts of a hydrophilic polymer, 8 parts of a 1,6 hexanediol atalylate, 2,5 dimethoxy-l 2-phenylacetophenone 1.5 parts, 2, 0.5 parts of di-t-butyl taresol is kneaded at 150 ° C. in a 3 L mixer and dissolved as a solvent for removal of the unexposed part, 2% concentration, 50 ° C. at a temperature of 50 ° C. The photosensitive properties and the laser processability were evaluated in the same manner as in Example 7 except that an aqueous solution of phenyl ether was used.

In addition, as a hydrophilic polymer, polyvinyl alcohol Z polyethylene glycol copolymer (manufactured by Heckiston Earth, GE597) was used. The results are shown in Table 5.

From Example 15, it is understood that when a hydrophilic polymer is blended, the photosensitive composition of the present invention is also excellent in water developability.

Comparative Example 1

Manufacturing of Elastomer-One Component

The components (a) to (i) are prepared by changing the amounts of styrene, 1,3 butadiene, sec butyl lithium and ethylene glycol jetyl ether, and (a) component and (i) component Using the same method as in Example 1 except that the blending ratio was varied, a single elastomer (Hi) was obtained. The results are shown in Table 6.

Comparative Examples 2 to 3

An elastomer-one composition (heat 2) shown in Table 7 was obtained in the same manner as in Comparative Example 1 except that the amount of the antiblocking agent added was changed. In addition, using the same method as in Example 1, except that the amounts of styrene, 1,3-butadiene and sec butyl lithium are changed to prepare the components (a) to (i), a single elastomer is produced. I got (He 3). The results are shown in Table 6.

Comparative Examples 4 to 6 Ito

It prepared by the method similar to Example 7, and evaluated the photosensitive characteristic and laser processability. The results are shown in Table 7.

[table 1]

* 1: Calcium stearate

Table 2]

* 1: Calcium stearate

Table 3]

* 2: 1, 6—Hexanediol diazallylate

* 3: 2, 2-Dimethoxy-l-phenylacetophenone * 4: B- 2000 * 5: 2, 6-di-t-butynorecreose-onele * 6: GE 597

Table 4]

* 2: 1, 6—Hexanediol diazallylate

[Table 5]

* 2: 1, 6—Hexanediol diazallylate

Table 6]

* 1: Calcium stearate

[Table 7]

* 2: 1, 6—Hexanediol diazallylate

* 3: 2, 2-Dimethoxy-1-2-Phacetophenone * 4: B-2000

* 5: 2, 6-Di-t-Butyno lek Reso 1 Nore * 6: GE 597

From Tables 1 to 2, Examples 1 to 6, which are one elastomer component including the (a) block copolymer and the (i) block (co) polymer of the present invention, are within the scope of the present invention. Yes, the fluidity is excellent, and the hardness that the gel content (toluene insoluble content) is low is 70 or less. Also, from Tables 3 to 5, Examples 7 to 15 which are photosensitive compositions using one of these elastomer constructions have image developability, clear printability even with small characters, dimensional stability, laser processing It can be seen that the water resistance and water developability are good.

On the other hand, as described in Tables 6 to 7, in Comparative Example 1, the blend ratio of (a) block copolymer and (i) block (co) polymer is outside the scope of the present invention. The photosensitive composition of Comparative Example 4 using this elastomer-one composition is inferior in clear printability in small letters and dimensional stability. . In Comparative Example 2, since the blend ratio of (a) block copolymer and (i) block (co) polymer is out of the range of the present invention, and the amount of the antiblocking agent is large, The photosensitive composition of Comparative Example 5 used is inferior in image developability as well as sharp printability with small letters, dimensional stability. In Comparative Example 3, the content of the aromatic compound in the (a) block copolymer is out of the range of the present invention, and additionally, the hardness of one constituent unit of the elastomer is too high. The photosensitive composition of No. 6 is inferior in sharp printability in small letters and dimensional stability.

Industrial applicability

The elastomer composition comprising the (a) block copolymer and the (i) block (co) polymer of the present invention is suitable for use in letterpress printing plate materials since the amount of gel is small.

Further, the photosensitive composition of the present invention is excellent in image developability, clear printability even in small characters, dimensional stability, laser processability, and when a hydrophilic polymer is blended, it is further improved in water developability. Because of its superiority, it is used as a plate material for letterpress printing represented by flexo printing and letter press printing, and is widely used mainly for films, labels, envelopes, heavy bags, wrapping paper, corrugated cardboard and the like.

Claims

The scope of the claims

[1] (a) A block copolymer comprising a polymer block mainly composed of at least two aromatic vinyl compounds and a polymer block unit mainly composed of at least one conjugated agent, wherein the block copolymer comprises And 20 to 40% of the total bonded aromatic vinyl compound content in the copolymer, and 10 to 50% of boule bond content in the polymer block mainly composed of conjugated diene, and a gel. A block copolymer having a peak molecular weight of 70,000 to 300,000 in terms of standard polystyrene measured by permeation chromatography (GPC), and a polymer block mainly composed of (i) one or more conjugated dienes. And a block (co) polymer which may contain one or more aromatic vinyl compound polymers and a totally bonded aromatic vinyl compound copolymer of the block (co) polymer. Content power ^ ~ 25%, and The boule bond content in the main polymer block is 10 to 80%, and the peak molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC) is 5,000 or more and less than 70,000. And (a) a block (co) polymer having a peak molecular weight of less than 1Z3 of the block copolymer, in a ratio of (a) Z (i) (weight ratio) = 60 to 955 to 40. Mer composition.

[2] The elastomer composition according to claim 1, wherein the content of the boule bond in the copolymer block consisting mainly of the conjugated diene of the block (co) polymer is 20 to 80%.

[3] The elastomer composition according to claim 1 or 2, wherein a boule bond content in a copolymer block mainly composed of a conjugated diene of a block (co) polymer is 30 to 80%.

[4] of elastomer composition

(ゥ) Mel 卜レレレレ (190. C, 21. 2 N) power O. l-20 g Z l o minutes,

(E) Toluene insoluble content is 20 ppm or less, and

(O) Hardness measurement method according to JIS K6253 Type A hardness is 30 to 70, and (force) an antiblocking agent is contained in an amount of not more than 0.2 parts by weight with respect to 100 parts by weight of the single elastomer.

An elastomer as claimed in any one of claims 1 to 3.

[5] (a) The content of the total bonded aromatic vinyl compound in the block copolymer is 20 to 35% by weight, and it is determined by gel permeation chromatography (GPC) of the block copolymer The peak molecular weight in terms of standard polystyrene is 100,000 to 250,000.

V. The elastomer composition according to any one of the above.

[6] (i) The peak molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC) of the block (co) polymer is from 10,000 to 50,000. The elastomer 1 structure of a statement.

[7] (K) An elastomer according to any one of claims 1 to 6,

(G) photopolymerizable unsaturated monomers, and

(F) Photopolymerization initiator

A photosensitive composition characterized by containing.

[8] In the photosensitive composition, 10 to 90% by weight of (k) one elastomer component, (5) 1 to 50% by weight of (k) photopolymerizable unsaturated monomer, and (k) photopolymerization initiator 0.10 to 1: L0% by weight [but (i)

The photosensitive composition according to claim 7, wherein + (f) + (f) = 100% by weight].

[9] The photosensitive composition according to claim 7 or 8, further comprising (co) liquid polybutadiene.

[10] The photosensitive composition according to Claim 9, wherein 50 wt% or less of (co) liquid polybutadiene is blended in the photosensitive composition.

[11] The photosensitive composition according to any one of claims 7 to 10, further comprising (j) a hydrophilic polymer.

12. The photosensitive composition according to claim 11, wherein 5 to 80% by weight of the hydrophilic polymer is blended in the photosensitive composition.