JPH0246460A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To improve the ink transition property of a water type flexoink, without reducing the water developing property of the composition, by blending a hydrophilic polyether urethane and a hydrophobic polymer. CONSTITUTION:The composition is composed of 50-97wt.% of the total of the hydrophilic polyether urethane (A) and the hydrophobic polymer (B), 3-50wt.% of an ethylenic unsatd. compd. and 0.1-2wt.% of a photopolymerization initiator. And, the component A is composed of a polymer obtd. by introducing a hydrophilic group to the main or the side chain of the polymer by allowing the polymer to react with polyoxyalkylene polyol and a prescribed polyisocyanate, and the component B is composed of a hydrophobic polyether urethane, etc. And, an additive such as a thermopolymerization forbidder, etc. is incorporated in the composition.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a photosensitive resin composition that can be developed with water, alkaline water, or an aqueous system containing a surfactant. The present invention relates to a composition for a photosensitive flexo plate material that is possible.

(Prior Art) Conventionally, photosensitive resin plates have been known to include a type that uses an organic solvent as a developer and an aqueous development type that contains water, alkaline water, a surfactant, and the like.

However, among conventional technologies, the organic solvent development type has the disadvantage that measures such as completely sealing the developing device, providing air conditioning equipment, and installing explosion-proof equipment are required in terms of pollution control, work environment, fire prevention, etc. there were.

On the other hand, even in the case of the water-developable type, there was a drawback that the water resistance of the composition after photopolymerization was poor due to the high hydrophilicity of the composition.

Regarding aqueous development flexo plates, for example,
No. 4-110287, JP-A-58-117537, etc. are known. However, in the former case, the developer is an alcohol/alkaline aqueous system such as sodium hydroxide/isopropyl alcohol/water, sodium carbonate/2-butoxycetanol/water, sodium sulfate/2-butoxycetanol/water, etc. was not intended to be used alone as a developer. Furthermore, the latter had the disadvantage that the main component polymer was a cationic polyester amide and there remained a problem in hydrolysis resistance.

Regarding other Fregiso plate compositions using polymers having polyether chains as soft segments, for example, JP-A-50-7603, JP-A-50-6403, JP-A-5
1-17285, JP 49-109104, JP 4932702, JP 49-33702, JP 49-110402, and JP 59413430
The number etc. are known.

However, all of these are liquid types, and solid water-based developable ones have not been reported.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned drawbacks of the conventional photosensitive resin plates that can be developed in water, namely, the limited water resistance of photopolymerized materials, the use of alcohol-containing water-based developers, and the problem of photopolymerization. A photosensitive resin plate composition that eliminates the problems of the liquid type, can be developed with water alone, is a solid plate, has sufficient water resistance for light weight, and has sufficient ink transferability for water-based flexographic inks. It is intended to provide something.

(Means for solving the problem) (B) Ethylenically unsaturated compound 3-50% by weight (C
) A photosensitive resin composition characterized by containing 0.1 to 2% by weight of a photopolymerization initiator.

In the present invention, component (A) is a mixture of hydrophilic polyether urethane and hydrophobic polymer at a ratio (weight ratio) of I:99 to 99:1, preferably 10:90 to 90:10, Examples of the polyether component constituting the hydrophilic polyether urethane include polyoxyalkylene polyols such as polyoxyethylene polyols, polyoxypropylene polyols, and polyoxytetramethylene polyols having a number average molecular weight of 200 to 10,000. can be mentioned.

Various polyisocyanates are exemplified as polyisocyanate-1, which is another essential component when constituting polyether urethane. For example, diphenylmethane diisocyanate (MD
I), diisocyana-1, such as l-lylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate l-(+1111), triphenylmethane triisocyanate, polymethylene poly Mention may be made of polyisocyanates such as phenyl isocyanate.

In addition, the component (8) polyether urethane having a hydrophilic group is a polyether urethane containing a hydrophilic group in the main chain or side chain, and the hydrophilic group is a nonionic group such as a polyethylene glycol group or a hydroxyl group. , carboxyl groups, sulfonic acid groups, phosphoric acid groups, phosphinic acid groups, anionic groups such as phosphinic acid groups, and cationic groups such as amino groups containing tertiary nitrogen atoms, quaternary ammonium groups, etc. . By introducing these hydrophilic groups into the main chain or side chain of a polymer, either singly or in combination, the polymer can be significantly swollen in water or an aqueous alkaline solution. A specific method for introducing these hydrophilic groups is to use a compound containing two active hydrogen atoms capable of reacting with an isocyanate group in the same molecule as the above-mentioned hydrophilic group, such as polyethylene glycol, dimethylolpropionic acid, Polymer raw materials include sodium diaminohense sulfonate, glycerin thinophosphate disodium salt, hydroxyethyl, sodium hydroxyethylphosphonate, sodium dimethylolphosphinate, N-methylethanolamine, and N,N-dimethyljetanol ammonium chloride. It can be easily copolymerized by hand. The hydrophilic polyether urethane obtained by introducing these hydrophilic groups is one that dissolves or disperses when immersed in water at 20°C or aqueous alkaline solution for 24 hours, or has a polymer weight increase rate of at least 200°C. % or more.

In the present invention, hydrophobic polymers are not limited to hydrophobic polyether urethane, but include those whose weight increase rate is 100% or less when immersed in water or alkaline aqueous solution at 20°C for 24 hours as shown above. It is a polymer and has good compatibility with the above-mentioned hydrophilic polyether urethane.

The hydrophilic or hydrophobic polyether urethane in the present invention can be chain-extended with various glycol components in addition to the above-mentioned components, if necessary. Specifically, for example, ethylene glycol, propylene glycol,
C1-6 aliphatic diols such as neopentyl glycol and hexamethylene glycol; ether glycols such as diethylene glycol and dipropylene glycol;

Aromatic diols such as ethylenediamine, 1.
Aliphatic diamines such as 6-hexamethylene diamine and isophorone diamine, with a number average molecular weight of 100 to 10,000
Examples include polyether polyamines such as polyethylene glycol diamine and polypropylene glycol diamine having a number average molecular weight in the range of 500 to 10,000, and butadiene diamines having a number average molecular weight in the range of 500 to 10,000.

The polyether urethane in the present invention can be produced by a conventional method. That is, it can be obtained by synthesizing a prepolymer from polyether glycol and polyisocyanate, then chain-extending it with various components or diamine components, and removing the solvent.

Next, the ethylenically unsaturated compound which is component (B) in the present invention is a compound containing at least one terminal ethylenic group, and this compound is polymerized by chain propagation addition polymerization initiated by free radicals. It is possible to form a union. Suitable ethylenically unsaturated compounds are unsaturated esters of polyols, especially such esters with alpha methylene carboxylic acids, such as ethylene glycol diacrylate, glycerol diacrylate, ethylene glycol dimethacrylate, 1.3 propanediol dimethacrylate. , 1,2゜4-butanetriol triacrylate, 1.4 cyclohexanediol diacrylate, 1゜3-propanediol diacrylate, 1. Examples include 6-hexanediol diacrylate and trimethylolpropane triacrylate.

In the present invention, the content of component (B) in the composition is 3 to 3.
It is preferably in the range of 50% by weight, especially from 10 to 40% by weight.
A range of % by weight is preferred. If the content is less than 3% by weight, the crosslinking density will drop significantly, resulting in the disadvantage that the photopolymerized product will not exhibit sufficient water resistance and, furthermore, it will not be possible to obtain satisfactory images during development. On the other hand, if it exceeds 50% by weight, the crosslinking density becomes high, the hardness of the plate composition becomes high, and the rubber elasticity required for a flexographic printing plate is not exhibited, which is not preferable.

Next, in the present invention, the photopolymerization initiating solvent, component (C), is one that can generate active species by actinic rays and initiate photoradical polymerization. Various known compounds can be used as useful photopolymerization initiators, and specifically, vicinal polyketone compounds such as diacetyl, benzyl, etc.
-Carbonyl alcohols such as benzoin, butyroin, etc., acyloin ethers, such as benzoin methyl ether, benzoin ethyl ether, α-substituted acyloins, such as α-alkylbenzoin, α-alkoxyacyloin, etc., and polynuclear quinones, etc.; used alone or in combination. The photopolymerization initiator is contained in the composition in an amount of 0.1 to 2% by weight, preferably 0.5 to 2% by weight.
It can be contained in a range of 1% by weight.

In addition, in the present invention, in addition to the above-mentioned components, a thermal polymerization inhibitor is added to the composition in an amount of 0 to 1% by weight, preferably 0.5% by weight, in order to simply prevent thermal polymerization without further suppressing the photocrosslinking reaction.
It may be contained in a range of 2 to 0.7% by weight. Useful thermal polymerization inhibitors include, for example, hydroquinone, hydroquinone monomethyl ether, catechol, pt-butylcatechol, and the like.

(Function) Although it is not clear why the composition of the present invention exhibits the contradictory performance of achieving both water developability and relief water resistance, the hydrophilic polymer forms a continuous phase and the hydrophobic polymer forms a dispersed phase. , it is assumed that this is due to moderate compatibilization occurring at the interface.

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

Synthesis Example 1 97.3 g of hexamethylene diisocyanate was added to polytetramethylene glycol +-50.0 g with a molecular weight of 1.100 in a reactor equipped with a stirring device, and the mixture was heated to 110 g under an N2 atmosphere.
A prepolymer was obtained by reacting at °C for 6 hours. Furthermore, 60.0 g of hexamethylene glycol, di-n-butyl Sn
Dilaurate 0.9g to dimethylacetamide 450g
The solution was added to the above prepolymer and reacted for 4 hours at 80°C under N2 atmosphere, and the reaction was terminated by confirming that the IR absorption spectrum (2215 cm-') of the remaining isocyanate disappeared. . Hydrophobic polyether urethane having rubber elasticity was obtained by removing dimethylacetamide under reduced pressure.

(hereinafter referred to as Polymer A).

Synthesis Example 2 Polytetramethylene glycol 15 with a molecular weight of 1,100
0.0g Quizamethylene diisocyanate (+101)
43.2 g was added to a reactor equipped with a stirring device to obtain a prepolymer in the same manner as in the synthesis example. dimethylolpropionic acid 2
0.9 g of di-n-butyl Sn dilaurate was dissolved in 450 g of dimethylacetamide, and the solution was added to the prepolymer described in section 3 and reacted at 80° C. for 4 hours under N2 atmosphere. Il of residual isocyanate? Absorption Spec I Le (2
The reaction was terminated by confirming that 215cnr') had disappeared. Dimethylacetamide was removed under reduced pressure to obtain a hydrophilic polyether urethane having rubber elasticity (hereinafter referred to as Polymer B).

Synthesis Example 3 A hydrophilic polyether urethane having rubber elasticity was obtained in the same manner as in Synthesis Example 2, except that 146.5 g of lID and 23.0 g of dimethylolpropionic acid were used in Synthesis Example 2 (hereinafter referred to as Polymer C). .

Synthesis Example 4 Molecule ff1l, +00 polyte 1-ramethylene glycol: 1
150 g of H1 and 141.4 g of H1 were reacted in the same manner as in Synthesis Example 1 to obtain a prepolymer. Lithium chloride bishydroxyethylaminoethanesulfonic acid 27.0
g and di-n-butyl Sn dilaurate (0.9 g) were dissolved in 450 g of dimethylacetamide, added to the above-mentioned prepolymer, and reacted at 80°C for 4 hours under N2 atmosphere to obtain an IR absorption spectrum (V-221
The reaction was terminated by confirming that 5 cm-') had disappeared. By removing dimethylacetamide under reduced pressure, a hydrophilic polyether urethane having rubber elasticity was obtained (hereinafter referred to as Polymer D).

Synthesis Example 5 In Synthesis Example 4, HDI 51.0 g lithium chlorinated bishydroxyethylethanesulfonic acid 40.0
A hydrophilic polyether urethane was obtained in the same manner as in Synthesis Example 4, except for using G (hereinafter referred to as Polymer E).

Synthesis Example 6 A hydrophilic polyether urethane was obtained in the same manner as in Synthesis Example 4 except that 81.4 g of HDI and 80.0 g of lithium-chlorinated bishydroxyethylethanesulfonic acid were used (hereinafter referred to as Polymer F).

Synthesis Example 7 A hydrophobic polyether urethane (hereinafter referred to as Polymer G) was obtained in the same manner as in Synthesis Example 4 except that 22.5 g of 1101 and 2.5 g of lithium-chlorinated bishydroxyethylethanesulfonic acid were used.

Synthesis Example 8 7.6 g of polytetramethylene glycol with a molecular weight of 850
,, ID121.8g dimethylolpropionic acid 1
5.4 g and di-n-butyl Sn dilaurate 1.0 g
A solution prepared by dissolving 300 g of Hydrahydrofuran was placed in a flask equipped with a stirrer, and the reaction was continued at 65°C for 3 hours. In a separate container, acrylonitrile butadiene oligomer containing terminal amine groups (Ilycav ATBN
A solution prepared by dissolving 55.3 g of 1300 x 16 (manufactured by Ube Industries, Ltd.) in 100 g of tetrahydrofuran was prepared as described in step 1 above. It was added into the flask at room temperature while stirring. A solution of 4.8 g of lithium hydroxide dissolved in 100 g of methyl alcohol was added to the obtained polymer solution while stirring at room temperature, and the mixture was further stirred for 30 minutes to obtain a hydrophilic polyether urethane (hereinafter referred to as Polymer 11). )
.

Table 1 shows the hydrophilic group content of each hydrophilic and hydrophobic polyether obtained in Synthesis Examples 1 to 8.

Example 1 Polymer A I7.5 g Polymer 852.5 g Hexamethylene glycol diacrylate-128.5, Benzyl dimethyl kecool 1 g and hydroquinone monomethyl ether 0.5 g Kneaded at 105°C using a heating kneader After defoaming, the resulting photosensitive resin composition was heated in a heat press at 105°C and a pressure of 100 kg/aft.
Between a polyester film with a thickness of 125 µ+n and a polyester film coated with 2 µm of polyvinyl alcohol on one side on the same polyester film, 1
A sheet having a thickness of 2.8 strokes was prepared by heating and pressing for minutes.

The top layer of polyester film was peeled off to leave a polyvinyl alcohol film on the photosensitive resin layer, and a negative film with an image was adhered thereon and exposed to a mercury lamp (manufactured by Dainippon Screen Co., Ltd.) at an illuminance of 25 W/nf, 5 Exposure was performed for minutes.

After removing the negative film, development was performed with a brush at 40°C for 15 minutes in neutral water containing 2% by weight of sodium alkylnaphthalene sulfonate, and the relief depth was 1.
, 2 mm image patterns were obtained. This image pattern faithfully reproduced the image of the negative film used. Furthermore, the obtained relief had good ink acceptance and transferability and showed a clear image.

Example 2 In Example 1, 35 g of polymer A, 55 g of polymer B
A relief pattern was obtained in the same manner as in Example 1 except for the following, and a relief that faithfully reproduced the image on the film and had excellent ink transferability and solvent resistance was obtained.

Example 3 In Example 1, 17.5 g of polymer A, 5 g of polymer
A relief pattern was obtained in the same manner as in Example 1 except that the amount was 2.5 g, and the relief faithfully reproduced the image of the negative film and had excellent ink transferability and solvent resistance.

Example 4 In Example 1, 35.0 g of polymer A, 3 polymer C3
A relief pattern was obtained in the same manner as in Example 1 except that 5.0g was used, and a relief was obtained that faithfully reproduced the image of the negative film and had excellent ink acceptance transferability and solvent resistance.

Example 5 In Example 1, 35.0 g of Polymer A, Polymer F
A relief pattern was obtained in the same manner as in Example 1 except that the weight was changed to 35.0 g. A relief pattern was obtained that faithfully reproduced the image of the negative film and had excellent ink acceptance transferability and solvent resistance.

Example 6 In Example 1, 35.0 g of Polymer D, 35.0 g of Polymer G. A relief pattern was obtained in the same manner as in Example 1 except that Og was used, and a relief that faithfully reproduced the image of the negative film and had excellent ink transferability and solvent resistance was obtained.

Example 7 In Example 1, 35.0 g of polymer E, polymer G
35. A relief pattern was obtained in the same manner as in Example 1 except that Og was used, and a relief that faithfully reproduced the image of the negative film and had excellent ink transferability and solvent resistance was obtained.

Example 8 In Example 1, polymer H35, Og, polyepichlorohydrin (Ebichroma-H Osaka Soda ■) 35.0 g
A relief pattern was obtained in the same manner as in Example 1 except for the following steps. A relief pattern was obtained that faithfully reproduced the image of the negative film and had excellent ink acceptance and transfer properties and solvent resistance.

Example 9 A relief pattern was obtained in the same manner as in Example 1 except that the polymer H35, Og and chlorinated polyethylene (H135 manufactured by Osaka Soda ■) were changed to 35.0 g, and the image on the negative film was faithfully reproduced. Reliefs with excellent ink transferability and solvent resistance were obtained.

Comparative Example A plate composition was prepared and evaluated in the same manner as in Example 1 using only the hydrophilic polyether urethanes of Polymers B, C, D, and Do shown in Synthesis Examples. All of them are capable of water phenomenon. I obtained a relief pattern with a relief of , but the relief part is
It did not show sufficient water resistance as a flexographic printing plate.

Examples 1 to 9 and comparative layered plate performance evaluation results are shown in Table 2.

Table 1 below: Hydrophilic group content of synthetic polymer (effects of the invention) The composition of the present invention having the above structure has a blend of a hydrophilic polyether urethane and a hydrophobic polymer, and therefore reduces water developability. In addition, it exhibits sufficient water resistance against water-based flexographic inks, so it is particularly useful for flexographic printing plates.

Patent applicant: Toyobo Co., Ltd.

Claims (1)

[Scope of Claims] (A) Hydrophilic polyether urethane and hydrophobic polymer 50-97% by weight (B) Ethylenically unsaturated compound 3-50% by weight (C) Photopolymerization initiator 0.1-2% by weight A photosensitive resin composition comprising: