JPH03296059A - Photosensitive resin composition for water-developable flexographic printing plate - Google Patents

Abstract

PURPOSE:To obtain a water-developable flexographic printing plate having resistance to water-base ink and flexibility by caking or toughening a large amt. of an ethylenic unsatd. compd. with a small amt. of a specified resin. CONSTITUTION:Polyamide (A) with polyethylene oxide segments having 150-5,000 number average mol. wt. and thermoplastic elastomer (B) with polyalkylene oxide segments having >=2.5 ratio of the number of C atoms to that of O atoms and 200-5,000 number average mol. wt. as soft segments are used as resin components in 0.5-5 weight ratio of A to B. A water-developable printing plate having improved ink resistance can be obtd. as a practical flexible or flexographic printing plate.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a water-developable photosensitive resin composition for flexographic printing plates, and in particular, a water-developable photosensitive resin composition with improved printing durability when using water-based inks. The present invention relates to a solid photosensitive resin composition for flexographic printing plates.

[Prior art] Chlorinated rubber, styrene-butadiene block copolymer,
Using an elastomer such as polyurethane as a carrier resin component,
A photosensitive resin composition containing an ethylenically unsaturated compound and a photopolymerization initiator is useful as a flexographic printing plate material by taking advantage of the characteristics of an elastomer.
No. 48611, No. 3024180, Special Publication No. 51-43
Many proposals have been made, such as in Publication No. 374.

However, since such photosensitive resin solid plate materials require halogenated hydrocarbon development, they have problems such as health problems and environmental pollution.

On the other hand, when considering photosensitive resin printing plates that are not particularly limited to flexographic printing applications, water- or alcohol-developable solid printing plates are well known;
As shown in Japanese Patent Publication No. 6-26125, Japanese Patent Publication No. 50-32645, Japanese Patent Publication No. 57-28485, etc., printing in which the photosensitive layer is a photosensitive resin composition whose carrier resin component is mainly water- or alcohol-soluble polyamide. The plate material is widely known. However, although printing plates obtained from such water- or alcohol-developable solid printing plate materials are resistant to oil-based inks, they are not resistant to inks containing polar solvents such as aqueous or alcohol-based. It is something that we do not have. In view of the above problems, the present inventors investigated the possibility of developing a photosensitive resin solid plate material that can be developed with water and is resistant to inks containing polar solvents such as water-based or alcoholic solvents. As a result, we have developed a method in which a large amount of photocurable components, which are mainly liquid components, are gelled and solidified using a small amount of a specific resin component, and furthermore, a specific component known as an organic solvent gelling agent, to form the desired photosensitive resin solid. It was discovered that a printing plate material could be obtained, and was previously proposed (for example, Japanese Patent Application Laid-open No. 63-278053, Japanese Patent Application Laid-open No. 63-287845, etc.).

[Problems to be Solved by the Invention] The object of the present invention is to further develop and improve the techniques described in the above-mentioned JP-A-63-278053 and JP-A-63-287845, and in particular to develop a technology that can be developed with water. An object of the present invention is to provide a photosensitive resin composition that provides a printing plate with improved flexibility, ink resistance, and printing durability as a practical flexible printing plate or flexographic printing plate.

[Means for Solving the Problems] The object of the present invention is to provide a photosensitive resin composition for a flexographic printing plate comprising a resin component, an ethylenically unsaturated compound, and a photopolymerization initiator, the resin component comprising: Polyamide (A) having a polyethylene oxide segment with a number average molecular weight of 150 to 5000 and a carbon number/oxygen number ratio of 2
．． 5 or more and a thermoplastic elastomer (B) having a polyalkylene oxide segment having a number average molecular weight of 200 to 5,000 as a soft segment, and having a weight ratio of B/A of 0. This is achieved by a photosensitive resin composition for a flexographic printing plate characterized by having a molecular weight in the range of 5 to 5.

That is, the present inventors solidified or toughened a large amount of ethylenically unsaturated compound with a small amount of a specific resin, which had not been thought of as a solid plate material, and applied this to a photosensitive resin composition. It was discovered that the photosensitive resin printing plate material has excellent developability and is suitable for a wide range of inks. Improvements to this printing plate material, especially water-based ink, which is the main ink for flexographic printing, have been developed. Further improvements in printing durability during use have led to the use of polyamide (A
), further using a thermoplastic elastomer (B) having a polyalkylene oxide segment with a carbon number/oxygen number ratio of 2.5 or more and a number average molecular weight of 200 to 5000 as a soft segment, and B/A 0 as the weight ratio of
The present invention was achieved by discovering that by selecting a range of 5 to 5, a water-developable flexographic printing plate unexpectedly having both water-based ink resistance, flexibility, and printing durability can be obtained.

Number average molecule used in the present invention 1150-500
The polyamide (A) having 0 polyethylene oxide segments is usually prepared by using α・ω-diaminopropylpolyoxyethylene as at least a part of the raw diamine component by a known method (for example, JP-A-55-79437, etc.). Polyetheramide or polyethylene glycol obtained by polycondensation or copolycondensation is used as at least a part of the raw diol component and is polycondensed or copolymerized by a known method (for example, JP-A-50-159586). Polyether ester amide obtained by condensation is used, but it is not particularly limited, and it broadly has a polyethylene oxide segment with a number average molecular weight of 150 to 5,000 in the main chain or side chain, and an amide bond in the main chain. Polymers having the following properties can be used.

Here, the number average molecular weight of the polyethylene oxide segment needs to be in the range of 150 to 5000, preferably 200 to 3000, and if the number average molecular weight is less than 150, the resulting plate material will have insufficient water developability. If it is larger than 5000, the obtained plate material will have insufficient shape retention. The number average molecular weight of the polyamide having these polyethylene oxide segments is 5,000 to 200,000, preferably 10,000 to 200,000.
It is preferably in the range of 50,000, and the amount used is preferably in the range of 3 to 20% by weight, more preferably 4 to 10% by weight, based on the total photosensitive resin composition. If the amount used is less than 3% by weight, the form retention of the obtained plate material is likely to be insufficient, and if the amount used is more than 20% by weight, the resulting printing plate will have poor flexographic ink solvent resistance, especially water resistance. It is easy to become unsatisfactory.

In addition, a thermoplastic elastomer (B
) is usually poly(1°2- and 1,3-propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, or diols that are block or random copolymers thereof. A polyether ester elastomer obtained by polycondensation or copolycondensation as at least a part of the raw material components by a known method (for example,
8-29896, etc.), polyether ester amide elastomers (e.g., Japanese Patent Publication No. 2-371, Japanese Patent Publication No. 2-372, etc.), polyether urethane elastomers (e.g., Japanese Patent Application Laid-Open No. 1987-109105, etc.) ), and furthermore, the diamine obtained by cyanethylating both ends of the above diols and then hydrogenating them is used as at least a part of the raw diamine component using a known method (for example, JP-A-55-79437, etc.). ) can be used, such as polyetheramide elastomers obtained by polycondensation or copolycondensation, but polyamide elastomers are particularly preferably used. The polyalkylene oxide segment, which is the soft segment of the elastomer used here, has a carbon number/oxygen number ratio of 2.5 or more, preferably 3.
．． 0 to 10.0, more preferably 4.0 to 8.0, and the number average molecular weight is 200 to 5000, preferably 300 to 3.
000, and if it is out of this range, the printing durability of the resulting flexographic printing plate will be insufficient.

From the viewpoint of achieving both water developability and printing durability when using a water-based ink, the weight ratio of the polyamide (A) having a polyethylene oxide segment and the elastomer component (B) used in the photosensitive resin composition of the present invention is B It is necessary that /A is in the range of 0.5 to 5, preferably 1.2 to 4. That is, if B/A is less than 0.5, the printing durability will be insufficient, and if it is more than 5, the water developability will be insufficient.

The effect of using the above-mentioned elastomers is to improve the printing durability of flexographic printing plates, which is the objective of the present invention, especially when using water-based ink, which is the main ink for flexographic printing, and from that point of view, the amount of these elastomers to be used is The amount is preferably in the range of 5% to 40% by weight based on the total photosensitive resin composition. If it is less than 5% by weight, the effect of improving printing durability is small, and if it exceeds 40% by weight, water development sex is significantly reduced. From the viewpoint of water developability, the amount of these elastomers used is preferably 30% by weight or less, and 20% by weight.
It is more preferable that it is the following.

The photosensitive resin composition of the present invention is characterized by containing the above polymer component, but the ethylenically unsaturated compound used as the other essential component has at least one ethylenic compound in the molecule. boiling point 1 with double bond
It is a compound that can be photopolymerized at temperatures of 00°C or higher, and all known compounds can be used. For example, in addition to various alkyl monoacrylates and alkyl monomethacrylates, reaction products of alkylene glycol and acrylic acid or methacrylic acid, unsaturated epoxy compounds and carboxylic acids, unsaturated carboxylic acids, or amines, etc. Synthesized mono- or poly-acrylates, mono- or poly-methacrylates, mono- or poly-valent acrylamides or methacrylamides, mono- or polyvalent urethane acrylates or methacrylates, and polyene oligomers such as liquid polybutadiene. etc., but are not limited to these, and can be selected as appropriate depending on the required characteristics of the desired molded product and in combination with the polyamide component that functions as a polymer gelling agent. However, the ethylenically unsaturated compounds preferably used to obtain the water-developable flexographic printing plate material, which is the object of the present invention, have one or more hydroxyl groups in the molecule, and Examples include ethylenically unsaturated compounds whose hydroxyl equivalents are in the range of 50 to 500, such as epichlorohydrin-modified bisphenol A diacrylate or epichlorohydrin-modified bisphenol A dimethacrylate represented by the following general formula. Acrylate (Hereinafter, both will be abbreviated as epichlorohydrin-modified bisphenol A di(meth)acrylate. Also, in the following explanation, all descriptions of (meth)acrylate are abbreviated to include both acrylate and methacrylate.) , caprolactone-modified 2-hydroxyethyl (meth)acrylate, epichlorohydrin-modified propylene glycol di(meth)acrylate, propylene oxide-epichlorohydrin-modified (meth)acrylate, epichlorohydrin-modified butyl (meth)acrylate, epichlorohydrin-modified diethylene glycol di(meth)acrylate, epichlorohydrin Modified phenyl (meth)acrylate, ethylene oxide modified phthalic acid (meth)acrylate such as β-hydroxyethyl β-acryloyloxyethyl phthalate, polycaprolactone modified (meth)acrylate, polyethylene oxide modified ethyl phthalate (meth)acrylate, polypropylene oxide Examples include, but are not limited to, modified ethyl phthalate (meth)acrylate, polypropylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, and others with a hydroxyl equivalent of 5
Ethylenically unsaturated compounds in the range of 0 to 500 can be widely used, and it is also possible to use two or more kinds together, and it is also possible to use them together with other ethylenically unsaturated compounds.

In particular, among these compounds, mono(meth)acrylates are preferably used to obtain the flexographic printing plate material which is the object of the present invention.

The amount of such ethylenically unsaturated compounds having one or more hydroxyl groups in the molecule is not particularly limited, but is 5 to 100% by weight based on the total ethylenically unsaturated compounds.
Preferably it is 30 to 100% by weight. Further, in order to obtain the flexographic printing plate material which is the object of the present invention, compounds preferably used as a part of the ethylenically unsaturated compound component include polyenes having a number average molecular weight of 300 to 20,000. is liquid polyisoprene, polybutadiene, etc., or the main chain, side chain,
Modified products that utilize the reactivity of terminal groups, such as maleic anhydride modified products, other acid anhydride modified products, isocyanate modified products, (meth)acrylic group-introduced products, epoxy modified products, etc. The use of the compound imparts favorable flexibility, rubber elasticity, polar solvent resistance, etc. to the flexographic printing plate obtained from the composition of the present invention.

The amount of polyenes used is not particularly limited, but is preferably 1 to 70% in the ethylenically unsaturated compound.
% by weight, more preferably 3 to 30% by weight; if it is less than 1% by weight, the addition effect will not appear, and if it is more than 70% by weight, the developability of the flexographic printing plate material will be poor. be.

As the photopolymerization initiator for rapidly photopolymerizing the composition of the present invention, all conventionally known compounds can be used. Examples include benzoin alkyl ethers, benzophenones, anthraquinones, benzyls, acetophenones, and diacetyls. These photoinitiators account for 100% of the ethylenically unsaturated compounds in the entire composition.
It can be used in a range of 0.01 to 10 parts by weight. Further, in order to increase the thermal stability of the photosensitive resin composition of the present invention, all conventionally known polymerization inhibitors can be used. Preferred polymerization inhibitors include phenols, hydroquinones, catechols, and phenothiazine. These heat stabilizers can be used in an amount of 0.001 to 5% by weight based on the total composition. Other additives that can be added include dyes, pigments, surfactants, antifoaming agents, ultraviolet absorbers, fragrances, and plasticizers. The use of a compound having one or more tertiary amine bonds and one or more hydroxyl groups in the molecule as an additive in the composition of the present invention is effective for improving molding processability and properties of molded products. Addition of such a compound improves the stability of the photosensitive resin composition of the present invention during preparation, and also improves the image of the printing plate obtained from the photosensitive resin composition of the present invention. In particular, such amine additives have a molecular weight of 300 to 3000. Furthermore, 700-20
00 compounds are preferably used. When using such an amine additive, a method of adding an active hydrogen-containing amine to form a tertiary amine during composition preparation can also be adopted.

The photosensitive resin composition of the present invention has a feature that there is a wide range of composition selection from the standpoint of compatibility because the amount of polyamide used as a resin component that functions as a gelling agent in a polymer state is small. In order to further improve the compatibility, shape retention, etc. of the printing plate material obtained from the photosensitive resin composition of the invention, an N-acylamino acid derivative, that is, N
- Acyl amino acid amine salt, N-acylamino acid amide, N-acylamino acid ester, or 12-hydroxystearic acid or its salt, metal soaps, alkylidene sorbitols, alkyl group-substituted or unsubstituted benzaldehyde, and polyhydric alcohol, preferably It is preferable to add at least one of a condensate with sorbitol and a polysaccharide acylated product, and these compounds are preferably used in an amount of 0.1 to 20% by weight based on the total amount of the composition.

As a method for producing the photosensitive resin composition of the present invention, first, an ethylenically unsaturated compound mixed with liquid components such as a heat stabilizer and a plasticizer is added to a resin such as polyamide (A) and a thermoplastic elastomer (B). Add ingredients and stir under stirring for 70 minutes.
After dissolving the resin component by heating to ~200°C, preferably 100 to 180°C, a photopolymerization initiator and other additive components are mixed and dissolved to produce a substantially solvent-free solution. . A reactive plasticizer component may be added at this stage. This solution can be cast or cast and cooled to directly obtain a molded product. The photosensitive resin composition of the present invention is characterized by being substantially a thermoreversible gel, and is a solid with practical strength at room temperature, but becomes a relatively low-viscosity liquid when heated. Therefore, an easy molding method that takes advantage of this property can be applied. The photosensitive resin composition of the present invention can be designed to become a liquid with a temperature of 1000 poise or less at 150°C, and further to become a liquid with a temperature of 1000 poise or less at 100°C.

In order to form a printing plate material using the photosensitive resin composition of the present invention, for example, a solution of the composition can be directly cast onto a support or a cover film. If necessary, dry film formation may be performed if a solvent is used, but normally it is formed without a solvent, so
Photosensitive resin sheets can be produced only by cooling, and thick objects can be easily molded. Generally, it is preferable to form a thin film layer mainly composed of water-soluble or dispersible resin on the upper surface of the photosensitive resin sheet in order to improve the adhesion with the negative film.

As the support, a metal plate made of steel, stainless steel, aluminum, copper, etc., which has an adhesive layer if necessary, a plastic sheet such as a polyester film, a synthetic rubber sheet, etc. is used, and the photosensitive layer usually has a 0. 1~10m
It is formed to a thickness of m.

In order to form a relief image for printing using the photosensitive resin composition of the present invention, a negative or positive original film is closely adhered to the photosensitive layer prepared as described above, and a wavelength of 300 to 450 mμ is usually centered on the photosensitive layer. UV rays from a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, xenon lamp, chemical lamp, power-bonarch lamp, etc. are irradiated to cause curing through a photoreaction. A relief is then formed on the support by dissolving or dispersing the uncured portion in water using a spray or brush developing device.

After drying this, a flexographic printing plate can be obtained by treating it with actinic light in the atmosphere.

The photosensitive resin composition of the present invention has the characteristic of containing an elastomer component that could not be used as a water-developable printing plate material in the past, so it can be used as a water-developable flexographic printing plate with improved printing durability. be.

[Example code] Hereinafter, the present invention will be explained in detail with reference to Examples.

Note that the numbers used in the following examples are parts by weight.

Synthesis Example 1 Known formulation (for example, JP-A-55-79437)
A polyether amide consisting of the following components was synthesized based on the following.

ε-caprolactam / Equimolar salt of hexamethylene diamine and adipic acid / Equimolar salt of α,ω-diaminopropylpolyoxyethylene (number average molecular weight 1000) and adipic acid = 20/20/60 Polyetheramide obtained here When the terminal group of is quantified, it is a primary amino group of 4.0XIO-
5 mol/g, carboxyl group 2. lXl0-5 mol/g
The number average molecular weight according to the terminal group determination method is approximately 330.
It was 00.

Synthesis Example 2 A polyether ester amide consisting of the following components was synthesized based on a known recipe (for example, JP-A-58-117537).

ε-caprolactam/polyethylene glycol with a number average molecular weight of 1000 and equimolar terephthalic acid mixture = 40/
70 The polyether ester amide obtained here had a GPC number average molecular weight in terms of nylon 6.6 of 28,000, and a terminal carboxyl group of 2.9XIO5 mol/g.

Synthesis Example 3 A polyether ester amide elastomer (polyalkylene oxide segment with a carbon number/oxygen number ratio of 4) consisting of the following components was synthesized based on a known recipe (for example, Japanese Patent Publication No. 2-372). .

Laurolactam/Equimolar adipic acid mixture with poly(tetramethylene oxide) glycol having a number average molecular weight of 650 = 40/70 The number average molecular weight of the polyether ester amide obtained here is 25,000 in terms of GPC nylon 6.6.

Synthesis Example 4 A polyether ester amide elastomer (polyalkylene oxide segment with a carbon number/oxygen number ratio of 3) consisting of the following components was synthesized based on a known recipe (for example, Japanese Patent Publication No. 2-372). .

Laurolactam/Equimolar adipic acid mixture with poly(propylene oxide) glycol having a number average molecular weight of 1,000 = 40/70 The number average molecular weight of the polyether ester amide obtained here is 22,000 in terms of GPC nylon 6.6.

Synthesis Example 5 1 mol of isophorone diamine and 2-
Ethylhexyl glycidyl ether 1 mole adduct
70°C, 3 hours reaction) was synthesized.

Example 1 5 parts of the polyetheramide obtained in Synthesis Example 1, 15 parts of the polyetheresteramide elastomer obtained in Synthesis Example 3, 0.05 part of heat stabilizer hydroquinone, and 15 parts of caprolactone-modified 2-hydroxyethyl methacrylate. 1 part, 25 parts of β-hydroxyethyl β'-acryloyloxyethyl phthalate, 10 parts of 2-acryloyloxyethyl hexahydrophthalic acid, and further maleic anhydride-modified polybutadiene "M2O0O-20" (manufactured by Nippon Petrochemical Co., Ltd.). 1 at 105℃ by mixing, heating, and increasing the temperature.
After stirring for an hour, 10 parts of the additive shown in Synthesis Example 5 was added, and after stirring at 140°C for 1 hour, 1.5 parts of benzyl dimethyl ketal was added as a photopolymerization initiator, and as other additive components. , 5 parts of 12-hydroxystearic acid, 5 parts of dibenzylidene sorbitol, and 5 parts of N-lauroyl-glutamic acid-α·γ-di-n-butylamide were added and dissolved. The solution obtained in this way was applied to a thickness of 1.
The thickness of the photosensitive layer is 170μ on a 00μ polyester substrate.
A solid photosensitive resin printing plate material was obtained by casting and coating so as to have a thickness of 0μ, and allowing it to stand at room temperature. On the photosensitive layer of this printing plate material,
Gray scale negative film for sensitivity measurement (Stouff
Manufactured by er, 21Steps 5ensitivity
Guide) and negative film for image reproducibility evaluation 15
0 line 3%, 5%, 10% halftone dots, diameter 200μ, and 3
00μ independent points, widths of 50 and 70μ thin lines) were placed in vacuum contact and exposed for 3 minutes from a distance of 1 m using a 2KW ultra-high pressure mercury lamp.

After the exposure was completed, development was performed using a brush type washing machine (liquid temperature: 25° C.) containing neutral water. Depth 1000 in 8 minutes development time
A relief image of μ was formed. As a result of evaluating this relief image, it was found that up to 14 steps remained in the grayscale area, and that the image area had almost completely reproduced 5% halftone dots, 300μ independent points, 50μ fine lines, etc. The hardness of the printing plate was 55 Shore A hardness after completion of the post-exposure to actinic light. 100 using water-based ink using this printing plate
A flexographic printing test of 000 sheets was conducted and good printed matter was obtained. This printing test is “Mercanday” 5DG12-8
This was carried out using a water-based ink (manufactured by G-Man) on a type flexographic label printing machine (manufactured by Markandy).

Comparative Example 1 In Example 1, the amount of polyetheramide obtained in Synthesis Example 1 was 15 parts, and the polyetheresteramide elastomer obtained in Synthesis Example 3 was not used.
A photosensitive resin printing plate material was similarly obtained, but in the same printing test as in Example 1, the printing plate obtained from this printing plate material showed remarkable thickening in the print area.

Comparative Example 2 In Example 1, a photosensitive resin printing plate material was similarly obtained by using the polyether ester amide obtained in Synthesis Example 2 instead of the polyether ester amide elastomer obtained in Synthesis Example 3. In a printing test similar to that in Example 1 using this printing plate, remarkable thickening occurred in the print area.

Example 2 8 parts of polyetheramide obtained in Synthesis Example 1, Synthesis Example 3
Polyether ester amide elastomer 8 obtained in
34 parts of β-hydroxyethyl β' acryloyloxyethyl phthalate, 0.05 parts of heat stabilizer hydroquinone
15 parts of caprolactone-modified 2-hydroxyethyl methacrylate and liquid rubber "8-stone polybutadiene" B
2000-20 (manufactured by Nippon Petrochemical Co., Ltd., liquid polybutadiene) was added to a mixture of 20 parts, stirred and heated, the temperature was raised, and the mixture was stirred at 110°C for 1 hour, and then the mixture obtained in Synthesis Example 5 was added. After further heating and stirring at 140°C for 1 hour, 1.5 parts of benzyl dimethyl ketal was added as a photopolymerization initiator, and N-lauroyl-shi-glutamic acid-α-γ-di-n-butylamide was added as an additive. 2 parts and 5 parts of dibenzylidene sorbitol were added and dissolved. The solution obtained in this way was cast onto a 100 μm thick polyester substrate on which a polyester adhesive had been applied and cured in advance so that the photosensitive layer had a thickness of 1500 μm.
The coating was applied and left at room temperature to obtain a solid photosensitive resin printing plate material.

A printing plate was obtained from this printing plate material in the same manner as in Example 1. The Shore A hardness of this printing plate was 61, making it an excellent flexographic printing plate suitable for water-based inks.

Example 3 In Example 1, the polyether ester amide obtained in Synthesis Example 2 was used instead of polyether amide,
A printing plate material was obtained in the same manner at a preparation temperature of 150°C. A printing plate was produced from this printing plate material in the same manner as in Example 1. This printing plate is even more suitable for printing using flexo ink than the printing plate obtained in Example 1,
A 200,000 print test using water-based ink gave good prints.

Example 4 5 parts of the polyetheramide obtained in Synthesis Example 1, 15 parts of the polyetheresteramide elastomer obtained in Synthesis Example 3, 0.05 part of heat stabilizer hydroquinone, and 15 parts of caprolactone-modified 2-hydroxyethyl methacrylate. 1 part, 20 parts of β-hydroxyethyl β'-acryloyloxyethyl phthalate, 5 parts of n-butylbenzenesulfonamide, 10 parts of sebacic acid, and maleic anhydride-modified polybutadiene "M2O0O-20" (Nippon Petrochemical Co., Ltd.) 1) at 105℃ by mixing, heating, and increasing the temperature.
After stirring for an hour, 10 parts of the additive shown in Synthesis Example 5 was added, and after stirring at 140°C for 1 hour, 1.5 parts of benzyl dimethyl ketal was added as a photopolymerization initiator, and as other additive components. , 5 parts of 12-hydroxystearic acid, 5 parts of dibenzylidene sorbitol, and 5 parts of N-lauroyl-glutamic acid-α·γ-di-n-butylamide were added and dissolved. The solution obtained in this way was applied to a thickness of 1.
The thickness of the photosensitive layer is 170μ on a 00μ polyester substrate.
A solid photosensitive resin printing plate material was obtained by casting and coating so as to have a thickness of 0μ, and allowing it to stand at room temperature. On the photosensitive layer of this printing plate material,
Gray scale negative film for sensitivity measurement (Stouff
Manufactured by er, 21Steps 5ensitivity
Guide) and negative film for image reproducibility evaluation (150 lines, 3%, 5%, 10% halftone dots, 200μ and 300μ diameter independent points, 50 and 70μ thin lines) were vacuum-adhered and heated at 2KW ultra-high pressure. Exposure was performed for 3 minutes from a distance of 1 m using a mercury lamp.

After the exposure was completed, development was performed using a brush type washing machine (liquid temperature: 25° C.) containing neutral water. Depth 1000 in 5 minutes development time
A relief image of μ was formed. As a result of evaluating this relief image, it was found that up to 14 steps remained in the grayscale area, and that the image area had almost completely reproduced 5% halftone dots, 300μ independent points, 50μ fine lines, etc. The hardness of the printing plate was 55 Shore A hardness after completion of the post-exposure to actinic light. 100 using water-based ink using this printing plate
A flexographic printing test of 000 sheets was conducted and good printed matter was obtained.

Example 5 In Example 4, the polyether ester amide elastomer obtained in Synthesis Example 4 was used instead of the polyether ester amide elastomer obtained in Synthesis Example 3.
When carried out in the same manner, similar results were obtained.

[Effects of the Invention] Since the present invention is configured as described above, it is possible to provide a photosensitive resin composition that provides a water-developable flexographic printing plate material with excellent resistance to flexographic printing using water-based ink. .

Claims (1)

[Claims] (1) A photosensitive resin composition for a flexographic printing plate comprising a resin component, an ethylenically unsaturated compound, and a photopolymerization initiator, wherein the resin component has a number average molecular weight of 150 to 500.
A polyamide (A) having a polyethylene oxide segment of 0, and a thermoplastic elastomer (B) having a polyalkylene oxide segment having a carbon number/oxygen number ratio of 2.5 or more and a number average molecular weight of 200 to 5000 as a soft segment. and the weight ratio of B/A is 0.5 to 5.
A water-developable photosensitive resin composition for a flexographic printing plate, characterized in that the composition is within the range of: