JP2581314B2 - Photosensitive resin plate material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin plate material used for water-developable flexographic printing.

[0002]

2. Description of the Related Art In recent years, printing plates for flexographic printing have changed from hand-carved plates to casting dies and photosensitive resin plates. Flexographic printing has many advantages such as low cost and low pollution as compared with other printing methods. Therefore, a printing technique with higher precision is desired. And, at the same time as the improvement of the printing machine, the use of a printing plate as a photosensitive resin is rapidly progressing.

Most of the above-mentioned photosensitive resin plate for flexographic printing uses a polyester sheet having good dimensional stability as a base material. In order to hold the photosensitive resin layer sufficiently adhered on the base material, the photosensitive resin plate is held. An adhesive layer is provided between the photosensitive resin layer and the substrate.

[0004] When a polyester sheet is used as a base material, it is reported that a system containing a copolymer polyester soluble in a solvent as a main component exhibits good adhesiveness. There are various reports using compositions containing this copolymerized polyester.

For example, Japanese Patent Publication No. 52-50563 discloses an adhesive layer formed of a polyester polyurethane resin formed by subjecting a polyester to urethane modification and then reacting with a polyfunctional isocyanate to form a crosslink. An adhesive layer formed by photocuring a photopolymerizable vinyl monomer on polyester is disclosed.

[0006] In addition to the above-mentioned prior art, an adhesive layer having a sufficient adhesive force even in a developing step has been proposed. For example, Japanese Patent Application Laid-Open Nos. 58-174945 and 60-146235 disclose an adhesive layer. And an adhesive layer formed of a composition comprising a copolymerized polyester, an isocyanate, an ethylenically unsaturated compound, and the like. However, Japanese Patent Application Laid-Open No.
According to Japanese Patent No. 174945, it is necessary to complete ionic addition reaction such as urethanization by aging at 50 ° C. for 2 weeks in order to obtain sufficient adhesive strength of the adhesive layer formed using the above composition. Therefore, there is a disadvantage that production efficiency is poor. Further, JP-A-60-146235 discloses that after forming an adhesive layer on a substrate, the isocyanate group which did not contribute to the adhesiveness with the substrate, that is, the photosensitive isocyanate group remaining in the adhesive layer. The resin layer is adhered. For this reason, after forming the adhesive layer on the substrate as described above, there is a disadvantage that the adhesive force decreases with time when the residual isocyanate decreases over a long time, and the photosensitive resin plate is industrially produced. In this case, there is a disadvantage that the process management is disadvantageous.

By the way, since flexographic printing uses an aqueous ink or an alcoholic ink, it has the merit of being less polluting at the printing stage than using other organic solvent inks. However, there is a problem that an organic solvent is used as a developing solution at the stage of making a flexographic printing plate precursor. In the field of letterpress printing, a water development method instead of alcohol development of a photosensitive resin plate has been established, and in the field of flexographic printing, it has been desired to perform plate making by a water development method.

In response to this demand, the present inventors have already developed a water-developable photosensitive resin for flexographic printing containing a chlorinated polyolefin. This water-developable photosensitive resin is soluble in an aqueous developer in a state where it is not photocured. The development of the water-developable photosensitive resin plate material is performed as follows. When a negative film image is placed on a plate material made of the above-mentioned photosensitive resin, and ultraviolet rays are irradiated from the photosensitive resin layer side, the photosensitive resin layer is irradiated with ultraviolet rays and photocured (image area).
Then, an uncured portion which is shielded by the negative film and not exposed to ultraviolet rays is generated. After the irradiation of the ultraviolet rays, the negative film is removed, the photosensitive resin plate is brought into contact with an aqueous developer by dipping or the like, and the uncured portion is removed. This image portion has practical durability to the aqueous ink or the alcoholic ink for flexographic printing.

However, the photocured portion of the photosensitive resin has a disadvantage that the adhesiveness to a polyester sheet substrate generally used for a photosensitive resin plate material for flexographic printing is insufficient. The lack of adhesiveness of the photosensitive resin layer to the base material causes the relief to be peeled or moved when the printing operation is performed by fixing the printing plate to the plate cylinder of the printing press with an adhesive tape. Further, when the printing plate is peeled off from the printing machine after printing and collected, the relief image is peeled off from the substrate, and the relief cannot be used for printing again.

The above-mentioned conventional adhesive layer has good adhesive strength to the polyester sheet substrate, but has little or insufficient adhesiveness to the photosensitive resin layer developed by the present inventors. There is a disadvantage that there is. Further, when the adhesive layer is left for a long time before the photosensitive resin layer is laminated on the formed adhesive layer, there is a disadvantage that the adhesive force changes remarkably with time, and the adhesive force gradually decreases.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to exhibit good adhesiveness to a water-developable photosensitive resin and to provide a long-term adhesive force. An object of the present invention is to provide a photosensitive resin plate material having an adhesive layer that does not deteriorate and having good adhesion between a photosensitive resin and a substrate.

[0012]

SUMMARY OF THE INVENTION The present invention provides a photosensitive resin plate material comprising a photosensitive resin layer for water-developable flexographic printing provided on a substrate via an adhesive layer. a glass transition temperature include 10 ° C. or less copolyester 90-50 wt%, and the mixture glass transition temperature comprising 50 ° C. or more copolyesters 10 to 50% by weight, polyfunctional iso sheet Ane <br/> And a compound having a hydroxyl group and an acryloyl group or a methacryloyl group, thereby achieving the object described above.

The resin composition for forming the photosensitive resin layer used in the present invention includes a polymer which dissolves or swells in water or an aqueous developer, an ethylenically unsaturated monomer and / or a hydrophobic polymer. And a photoinitiator. Examples of such a resin composition include the compositions disclosed in JP-A-60-211451 and JP-A-60-173055. Preferably, JP-A-2-30
The photosensitive resin composition described in JP-A-5805 is used.

The photosensitive resin composition described in the above specification of the invention comprises (A) a hydrophobic polymer having a glass transition temperature (hereinafter, referred to as Tg) of 5 ° C. or less, (B) a hydrophilic polymer,
(C) ethylenically unsaturated compound, (D) the hydrophilic polymer
The solvent of (B) has a solubility higher than the solubility of the hydrophobic polymer (A), and (E) a photopolymerization initiator, and the content of the hydrophilic polymer (B) is greater than that of the hydrophobic polymer (A). It is a photosensitive resin composition characterized by having a small amount. In this resin composition, the layer mainly composed of the hydrophilic polymer (B) surrounds the layer mainly composed of the hydrophobic polymer (A) to form particles, and the particles are dissolved in the solvent (D). It is characterized by being dispersed.

Examples of the hydrophobic polymer (A) include compounds used as general-purpose elastomers.
For example, a polymer obtained by polymerizing a conjugated diene-based hydrocarbon, a copolymer obtained by polymerizing a conjugated diene-based hydrocarbon and a monoolefin-based unsaturated compound, a polymer containing no conjugated diene-based hydrocarbon, and the like. No.

As the conjugated diene hydrocarbon, 1,3-
Butadiene, isoprene, chloroprene and the like are used. These conjugated diene hydrocarbons can be used alone or 2
You may mix and use more than one type.

Examples of the monoolefinically unsaturated compound include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, acrylamide, and methacryl. Amides , vinyl acetates, acrylates, methacrylates and the like are used.

Examples of the polymer obtained by polymerizing the conjugated diene hydrocarbon include a butadiene polymer, an isoprene polymer and a chloroprene polymer.

Copolymers obtained by polymerizing the above conjugated diene hydrocarbon and monoolefinic unsaturated compound include styrene butadiene copolymer, styrene-isoprene copolymer, styrene-chloroprene copolymer, acrylonitrile -Butadiene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile-chloroprene copolymer, methyl methacrylate-butadiene copolymer, methyl methacrylate-isoprene copolymer, methyl methacrylate-chloroprene copolymer, methyl acrylate -Butadiene copolymer, methyl acrylate-isoprene copolymer, methyl acrylate-chloroprene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-isoprene-styrene copolymer, acrylonitrile-cook Ropuren - styrene copolymer.

Examples of the polymer containing no conjugated diene-based hydrocarbon include elastomers containing a specific amount of chlorine and non-conjugated diene-based hydrocarbons. Since the physical properties of the photosensitive resin composition after light irradiation greatly depend on the properties of the hydrophobic polymer (A), it is preferable that the hydrophobic polymer (A) is essentially a rubber elastic body, and these polymers are used. Of those with rubber elasticity, the chlorine content is 50 to 10% by weight
And more preferably a polymer having a Tg of 5 ° C. or lower, particularly -10 ° C. or lower. If the chlorine content is out of the above range, the flexibility of the polymer tends to be impaired or the thermal stability tends to deteriorate. Therefore, the photosensitive resin composition may be too hard or may be easily discolored.

Examples of such a polymer include a polymer of a chlorine atom-containing monomer and a polymer of a chlorine atom-containing monomer and another monomer copolymerizable with the monomer. There are compounds obtained by reacting a copolymer, chlorine or an active substance containing chlorine with a polymer containing no chlorine atom.

Examples of the polymer of the monomer containing a chlorine atom include an epichlorohydrin polymer.

Examples of the copolymer of the above monomer containing a chlorine atom and another monomer copolymerizable with this monomer include, for example, epichlorohydrin-ethylene oxide copolymer and epichlorohydrin-propylene oxide copolymer. Epichlorohydrin rubber which is a copolymer of the allyl glycidyl ether and a copolymer thereof (epichromer manufactured by Osaka Soda Kogyo Co., Ltd., HYDRIN manufactured by Goodvich Co., Ltd., GECHRON manufactured by Zeon Corporation, Zeospan, Hercules)
HERCLOR).

Examples of the compound obtained by reacting chlorine or an active substance containing chlorine with a polymer containing no chlorine atom include, for example, polyethylene chloride (manufactured by Showa Denko KK).
Eraslen, Daisorak, Osaka Soda Industry Co., Ltd.
HORTALITZ manufactured by echst, DOWC manufactured by Dow Chemical
PE) vinyl chloride copolymer, vinylidene chloride, chlorinated polypropylene, chlorinated ethylene-propylene rubber and the like.

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

The above-mentioned hydrophobic polymer (A) may be blended with an elastomer having good compatibility with the hydrophobic polymer (A) and having ozone resistance, such as acrylic rubber and polyurethane elastomer. Good.

Since the conjugated diene-based hydrocarbon polymer containing a chlorine atom and its copolymer contain a carbon unsaturated bond in the main chain, the chemical stability such as weather resistance is higher than that of the case where only a saturated bond is used. There is a disadvantage of inferiority, which is not preferable.

The content of the hydrophobic polymer (A) in the photosensitive resin composition is preferably from 20% by weight to 80% by weight, and more preferably from 30% by weight to 70% by weight. preferable. If it is less than 20% by weight, the physical properties and shape retention of the printing plate may be insufficient, and if it is 80% by weight, the photopolymerizability may be poor.

The hydrophilic polymer (B) is water or an aqueous solution containing water as a main component, an alkaline aqueous solution, an acidic aqueous solution,
A polymer that is soluble, swellable and dispersible in a developer containing an organic solvent or a surfactant. Examples of the hydrophilic polymer (B) include —NH ₂ , —OH, —COOM group, and —SO ₃ M group (M represents a hydrogen atom, Group I, II, or Group III element, amine, or ammonium. Examples of Group I, II, and III elements include alkali metals such as sodium, potassium, and lithium, alkaline earth metals such as calcium and magnesium, boron, and aluminum, and the like. And a compound having no cross-linked structure. Examples thereof include general-purpose resins such as polyvinyl alcohol (PVA) and carboxymethyl cellulose, and diene rubber obtained by copolymerizing (meth) acrylic acid and a diene compound, and liquid polybutadiene modified with maleic anhydride. Specifically, -COOM group-containing polyurethane, -COOM group-containing polyurea urethane, -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 copolymer, -COOM group-containing polybutadiene, polyacrylamide, sodium polyacrylate, polyvinyl alcohol (PVA), carboxymethyl cellulose (CM
C), hydroxyethylcellulose (HEC), methylcellulose (MC), polyethylene oxide, polyethyleneimine, and derivatives of such compounds can be used. Further, the hydrophilic polymer may have a polyoxyalkylene chain as a hydrophilic part other than the -COOM group, and may have an ethylenically unsaturated group so as to act as a crosslinking agent. These compounds may be used alone or in combination of two or more.

Particularly preferred are polymers having an effective backbone of 50 to 50,000 equivalents / 10 ⁶ g of -COOM. If the -C00M group is less than 50 equivalents / 10 ⁶ g, the affinity for water is poor and development with neutral water is difficult, while if it exceeds 50,000 equivalents / 10 ⁶ , the water-resistant ink resistance is inferior.

Further, in addition to the above hydrophilic polymer, for example, a polymer having a hydrophilic group such as a hydroxyl group, an amino group or a sulfonic acid group and / or a polyoxyalkylene chain may be used in combination as the hydrophilic polymer.

The content of the hydrophilic polymer (B) in the photosensitive resin composition is preferably 5 to 50% by weight, more preferably 7 to 50% by weight.
-40%, more preferably 7-30% by weight. If the amount is out of the range of 5 to 50% by weight, the resistance to the aqueous developer and the affinity for the water-resistant ink may be insufficient. Further, the content of the hydrophilic polymer (B) is preferably smaller than that of the hydrophobic polymer (A). If the content of the hydrophilic polymer is larger than that of the hydrophobic polymer (A), the affinity for the water-resistant ink may be insufficient.

The compound used to neutralize at least a part of the carboxyl groups contained in the hydrophilic polymer includes alkali metal hydroxides such as lithium hydroxide, potassium hydroxide and sodium hydroxide. Alkali metal carbonates such as lithium carbonate, potassium carbonate and sodium carbonate; alkali metal alkoxides such as potassium-t-butoxide and sodium methoxide; water of polyvalent metals such as calcium hydroxide, magnesium hydroxide and aluminum hydroxide Oxides, polyvalent metal alkoxides including aluminum isopropoxide, tertiary amines such as triethylamine and tri-n-propylamine, secondary amines such as diethylamine and di-n-propylamine,
Primary amines such as ethylamine and n-propylamine, cyclic amines such as morpholine, N, N-diethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth)
Examples thereof include amino group-containing (meth) acrylates such as acrylates, ammonium carbonate salts and the like. They are,
A single kind or a combination of plural kinds may be used.

The above ethylenically unsaturated compound (C) is a compound containing at least one terminal ethylenic group. The ethylenically unsaturated compound (C) is capable of forming a high molecular weight polymer by free radical-initiated chain growth addition polymerization. Suitable ethylenically unsaturated compounds (C)
Examples include unsaturated esters of polyols, especially such esters with α-methylene carboxylic acid, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, glycerol diacrylate, 1,3-propane Diol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,2,4-butanetriol tri (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, 1,6-hexane Diol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, diallyl phthalate, fumaric acid diethyl ester, maleic acid dibutyl ester, and the like; and N-methylmaleimide, N-ethylenemaleimide, N-laurylmaleimide, and the like. N-substituted maleimide compounds Oligo (meth) such as oligonitrile butadiene di (meth) acrylate, oligonitrile urethane (meth) acrylate, oligourethane di (meth) acrylate, oligobutanediene di (meth) acrylate, oligobutadiene / urethane di (meth) acrylate Acrylates are mentioned. These compounds may be used alone or in combination of two or more.

The content of the ethylenically unsaturated compound (D) in the composition is preferably 1 to 50% by weight. More preferably 5 to
40% by weight. When the amount is less than 1% by weight, photopolymerization of the resin composition is insufficient, and an image may not remain after development. Conversely, if the content is more than 50% by weight, the shape retention may become insufficient, and the plate after light irradiation becomes too hard and brittle, which is not preferable as a flexographic printing plate.

The solvent (D) is a solvent in which the solubility of the hydrophilic polymer (B) is larger than that of the hydrophobic polymer (A).
It is a highly polar solvent that swells, disperses, and dissolves the hydrophilic polymer (B), but hardly swells the hydrophobic polymer (A). Examples of such a solvent include water, an alcohol having 1 to 5 carbon atoms, and the like.

The water includes surfactants such as sodium alkylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium alkylsulfonate and sodium alkylethersulfonate, fatty acids, lithium hydroxide, potassium hydroxide, sodium hydroxide, boric acid, and the like. It may contain sodium, sodium carbonate, sodium acetate, magnesium acetate or a salt thereof.

Examples of the alcohol include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, t-butyl alcohol, pentyl alcohol, neopentyl alcohol and the like.

Further, if the solvent satisfies the requirement of (D),
Ester, ketone, amide solvents and the like can be used. Specific examples include ethyl acetate, butyl acetate, isobutyl acetate, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, methyl butyl ketone, formamide, dimethylformamide, dimethylacetamide, and the like.

These solvents may be used alone or as a mixed solvent obtained by mixing a plurality of types.

The content of the solvent (D) in the photosensitive resin composition affects the performance of the flexographic printing plate. A preferable range of the content is 0.001% by weight to 5% by weight.
More preferably, it is 0.001% by weight to 2.0% by weight. If the amount exceeds 5% by weight, the plate material before photopolymerization and curing may become soft and cause cold flow, plastic deformation, and the like, and the projections of the relief of the printing plate obtained by photopolymerization may be deformed (so-called low Spots), making it difficult to obtain a clear image when printed.

As the photopolymerization initiator (E), for example,
Benzophenones, benzoins, acetophenones,
Examples include benzyls, benzoin alkyl ethers, benzylalkyl ketals, anthraquinones, thioxanthones and the like. Specifically, benzophenone, chloro benzophenone, benzoin, acetophenone, benzyl, benzoyl Nme Chirueteru, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzyl diethyl ketal, benzyl di isopropoxide pin <br/> Ruketaru, There are anthraquinone, 2-chloroanthraquinone, thioxanthone, 2-chlorothioxanthone and the like.

The photopolymerization initiator (E) is preferably contained in the photosensitive resin composition in an amount of 0.01 to 5% by weight. More preferably, it is 0.1 to 3% by weight. If it is less than 0.01%, the photopolymerization initiation ability may be insufficient, and if it is more than 5%, the photopolymerization initiator (E) itself blocks light and the curing depth of the photosensitive resin layer becomes insufficient. However, it is not preferable because an image is easily chipped in the developing step.

Further, without controlling the photocrosslinking reaction,
In order to simply prevent thermal polymerization, a thermal polymerization inhibitor (F) may be contained in the photosensitive resin composition in addition to the above components (A) to (E). Useful thermal polymerization inhibitors (F) include, for example, hydroquinone, hydroquinone monoethyl ether, catechol, pt-butylcatechol, 2,6-di-t-butyl-p-cresol and the like. Thermal polymerization inhibitor (F)
Is preferably in the range of 0.001 to 5% by weight in the photosensitive resin composition.

In the photosensitive resin composition, other plasticizers such as liquid polybutadiene rubber, liquid polyacrylonitrile butadiene rubber, liquid polystyrene butadiene rubber, liquid rubber such as liquid isoprene rubber, polyvinyl chloride, chlorinated polyethylene, chlorinated polyethylene, It can contain relatively low molecular weight elastomers such as polypropylene, and fine powders such as silica and diatomaceous earth.

Each of the components (A) to (F) of the photosensitive resin is dissolved and mixed in a suitable solvent in an arbitrary order.
Layer composed mainly of hydrophilic polymer (B) is a hydrophobic polymer
Particles are formed by surrounding the layer containing (A) as a main component, and the particles are dispersed in the solvent (D). With the solvent (D),
For example, dissolution tetrahydrofuran, dioxane, methyl ethyl ketone, toluene, cyclohexanone, a solvent consisting of chloroform or the like, each composition component (A) is ~ (F), and then dissolved and mixed under ordinary conditions, the hydrophobic polymer (A) Then, the hydrophilic polymer (B) is obtained by swelling and dispersing.

The substrate used in the present invention is a material having good dimensional stability. For example, metal plates such as iron, aluminum, and stainless steel, and films, sheets, papers, and cloths made of polymers such as rubber and plastic are used, and polyethylene terephthalate is preferably used. These materials are combined and used in the form of a sheet or a cylinder.

The adhesive layer disposed between the photosensitive resin layer composed of the photosensitive resin composition and the base material contains 90 to 50% by weight of a copolymerized polyester having a glass transition temperature of 10 ° C. or less. It is formed using a mixture containing 10 to 50% by weight of a copolyester having a transition temperature of 50 ° C. or higher, a polyfunctional isocyanate, and a compound having a hydroxyl group and an acryloyl group or a methacryloyl group in a molecule. .

The above mixture has a glass transition temperature of 10 ° C.
The following copolymerized polyester is contained in an amount of 90 to 50% by weight, and the copolymerized polyester having a glass transition temperature of 50 ° C or higher is contained in an amount of 10 to 50% by weight. Preferably, the content of the copolyester having a glass transition temperature of 10 ° C or lower is 80 to 60% by weight, and the content of the copolyester having a glass transition temperature of 50 ° C or higher is 20 to 40% by weight. If the content of the copolyester having a glass transition temperature of 10 ° C. or lower is more than 90% by weight, the resulting adhesive layer will be undesirably blocked since the coating surface of the adhesive layer will become tacky and block. When the content ratio is less than 50% by weight, the adhesiveness to a polyester film as a base material is poor.

The above two types of copolymerized polyesters include:
Polyester polyols synthesized from carboxylic acids and their derivatives and polyhydric alcohols and soluble in organic solvents are used.

Examples of the carboxylic acids and derivatives thereof include terephthalic acid, sebacic acid, isophthalic acid,
Adipic acid, trimellitic acid, 5-sodium sulfoisophthalic acid and the like, and the polyhydric alcohols include, for example, ethylene glycol, neopentyl glycol, butanediol, polytetramethylene glycol,
Examples include bisphenol A ethylene oxide adducts and trimethylolpropane.

By appropriately combining the above carboxylic acids and polyhydric alcohols, the glass transition temperature is 10
Polyester having a glass transition temperature of 50 ° C or lower
The above copolymerized polyester is produced. Further, the combination of the above carboxylic acids and polyhydric alcohols, the softening point of the obtained polyester polyol changes,
When a polyethylene terephthalate film is used as the substrate, it is preferable that its softening point is 150 ° C. or lower from the viewpoint of adhesion to the substrate. If the softening point is 125 ° C or less,
The adhesive strength of the adhesive layer becomes insufficient, and the adhesiveness of the surface of the adhesive layer increases. Therefore, a limited combination of raw materials is required to maintain the balance of these properties. The polyester polyol has a molecular weight of 15,000 to 30,000
And the hydroxyl value (KOH mg / g) is preferably in the range of 2 to 10. When a polyester polyol having a molecular weight and a hydroxyl value in the above range is used, a coating operation can be easily performed during the production of the adhesive layer.

Examples of the polyfunctional isocyanate include aliphatic or aromatic polyvalent isocyanates containing two or more isocyanate groups in the molecule, and adducts of these polyisocyanates and polyhydric alcohols. And blocked isocyanates that generate an isocyanate group upon thermal dissociation.

Examples of the compound having a hydroxyl group and a (meth) acryloyl group in the molecule (hereinafter referred to as an acrylate compound) include, for example, pentaerythritol mono-, di- and tri (meth) acrylates, and trimethylolpropane mono- and di- (Meth) such as (meth) acrylate and (meth) acrylate of 2-hydroxyethyl
Acrylates are mentioned.

The above composition for forming an adhesive layer (hereinafter referred to as an adhesive composition) is obtained by mixing the above three components, and the content of each component in the adhesive composition is determined by the amount of the copolymerized polyester. Preferably, the polymer mixture is 80 to 55% by weight, the polyfunctional isocyanate is 15 to 30% by weight, and the (meth) acrylate compound is 5 to 15% by weight.

Among the above components, the acrylate compound which most affects the adhesiveness is 5% by weight.
If it is less than 3, the adhesive strength to the photosensitive resin layer tends to decrease with the passage of time after the formation of the adhesive layer. 15% by weight
If it exceeds, the adhesive strength to the polyester substrate may be low.

A small amount of other components can be added to the adhesive composition, if necessary. For example, dyes,
Examples include an ultraviolet absorber and an anti-blocking agent.

The easiest way to form an adhesive layer on a substrate is to apply a solution of the above adhesive composition and dry it. As a coating method, a known method such as a reverse roll or a gravure coat can be applied. For coating liquid,
It is preferable to add a known substance as a curing catalyst for polyvalent isocyanate, because the thermal reaction during drying can be promoted. The thickness of the applied and dried adhesive layer is preferably in the range of 0.5 to 100 μm, more preferably 2 μm to 50 μm.
μm.

After removing the solvent from the photosensitive resin composition, the photosensitive resin plate material of the present invention can be prepared by heating and pressing on the adhesive layer of the substrate provided with the adhesive layer. it can. Furthermore, on the surface where the photosensitive resin is
A cover film in which a water-soluble polymer, for example, a polyvinyl alcohol coating film is coated on the photosensitive resin surface, may be pressure-bonded so that the coating film surface is in contact with the photosensitive resin surface (in this case, the exposure is This is performed after the cover film is removed, and only the coating film remains on the photosensitive resin layer).

A negative film having a transparent image is applied to the photosensitive resin layer of the photosensitive resin plate material obtained as described above, and ultraviolet rays are irradiated from a light source on the negative film. By removing the non-image area at about 25 ° C. to 45 ° C. using a developer, a printing plate having a clear relief image can be obtained.

The wavelength of the ultraviolet light used for curing the photosensitive resin layer is preferably in the wavelength range of 150 to 500 nm, particularly 300 to 400 nm. Examples of the light source include a low-pressure mercury lamp, a high-pressure mercury lamp, and a carbon arc lamp. Light, ultraviolet fluorescent light,
Chemical lamps, xenon lamps, zirconium lamps and the like are preferred.

As the developer, water having a pH of 5.0 to 9.0 is preferable, and water for daily use can be used. An aqueous solution containing the water as a main component, an alkaline compound such as sodium hydroxide and sodium carbonate, a surfactant, a water-soluble organic solvent, and the like may be used. As the surfactant, sodium alkylnaphthalenesulfonate, sodium alkylbenzenesulfonate, and the like are preferable, and in addition, anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants can be used.

The development of the photosensitive resin plate material of the present invention is carried out by immersing or spraying the above-mentioned developer while bringing the exposed printing plate into contact with a brush. The non-exposed photosensitive resin (and the polyvinyl alcohol coating film, if there is one) is swelled and zeidized by contact with the developing solution, so that it is easily removed by brushing.

The developer adhering to the printing plate after development is washed off with water, and then the adhering water is wiped off and dried. Drying is performed with forced air or infrared rays, but the conditions are not particularly limited. The printing plate after drying is further exposed by the light source used for exposure, and the photosensitive resin on the printing plate is completely cured by the subsequent exposure operation.

In the adhesive layer of the printing plate material of the present invention, a film obtained by reacting a mixture of a copolymerized polyester, a polyfunctional isocyanate and an acrylate compound having a hydroxyl group is insoluble in a solvent and It has good adhesion to the photosensitive resin layer for developable flexographic printing. Moreover, the adhesive strength of the coating is maintained for a long time after the formation of the adhesive layer on the base material such that the isocyanate groups remaining in the adhesive layer disappear. From this, it is presumed that in the photosensitive resin plate material of the present invention, the remaining isocyanate groups are not essential for adhesion between the photosensitive resin layer and the adhesive layer. When the adhesive layer has a residual isocyanate group, it is necessary to take measures such as avoiding contact between the adhesive layer and the outside air in order to preserve the isocyanate group, which is very disadvantageous in storage. But,
In the adhesive layer used in the present invention, such consideration is not required, and the adhesiveness can be easily maintained.

Therefore, after the adhesive layer is formed on the substrate, the photosensitive resin layer can be pressure-bonded even after a while. That is, even after the formation of the adhesive layer, good adhesiveness can be maintained even with the adhesive layer left at room temperature for a long time after the formation of the adhesive layer. The ability to maintain the adhesiveness of the adhesive layer for a long time is very advantageous in controlling the production process of the photosensitive resin plate.

[0067]

The present invention will be described in detail below with reference to examples.

Example 1 Preparation of Photosensitive Resin Composition 21.8 parts by weight of hexamethylene diisocyanate, 15.4 parts by weight of dimethylolpropionic acid, 7.6 parts by weight of polytetramethylene glycol (PG-100 manufactured by Nippon Polyurethane Industry Co., Ltd.) And a solution of 1.0 part by weight of di-n-butyltin dilaurate dissolved in 300 parts by weight of tetrahydrofuran,
The mixture was placed in a 1-liter flask equipped with a stirrer, and the reaction system was heated to 65 ° C. for 3 hours while continuing to stir.

In another reaction vessel, an acrylonitrile-butadiene oligomer having a terminal amino group (Hycar ATBNX 1300
55.3 parts by weight of × 16 Ube Industries, Ltd.) were dissolved in 100 parts by weight of methyl ethyl ketone, and this solution was added to the 1-liter flask with stirring at room temperature to obtain a polymer solution. The obtained polymer solution was dried under reduced pressure to remove tetrahydrofuran and methyl ethyl ketone, thereby obtaining a polymer having a number average molecular weight of 21,000.

Next, 100 parts by weight of the obtained polymer was dissolved in 100 parts by weight of ethyl ethyl ketone, and a solution in which 4.8 parts by weight of lithium hydroxide was dissolved in 100 parts by weight of methyl alcohol was stirred at room temperature while stirring. Was added. After the addition, the mixture is further stirred for 30 minutes to form a hydrophilic polymer (1).
I got

10 parts by weight of the hydrophilic polymer (1), 45 parts by weight of chlorinated polyethylene (H-135 manufactured by Osaka Soda Co., Ltd.) as a hydrophobic polymer, and styrene-butadiene rubber (JSR1)
507 Nippon Synthetic Rubber Co., Ltd.) 15 parts by weight, butadiene oligoacrylate (PB-A Kyoeisha Oil & Fats Co., Ltd.) 28.5 parts by weight, benzyl dimethyl ketal (Irgacure 651, Ciba Geigy Co., Ltd.) 1 part by weight, Hydroquinone monomethyl ether 0.5 part by weight, toluene 40 parts by weight, water 1
Dissolve and disperse in 0 parts by weight and use a heating kneader at 105 ° C
To obtain a photosensitive resin composition.

Preparation of Adhesive Composition Copolyester having a glass transition temperature of 7 ° C. (Toyobo Co., Ltd. Byron RV-30SS, solid content concentration: 30% by weight) 18.1
Parts by weight (70% by weight) and a glass transition temperature of 67 ° C. copolymerized polyester (Toyobo Co., Ltd. Byron RV-20SS,
A mixture (70% by weight) of 7.7 parts by weight (30% by weight) of a solid content concentration of 30% by weight and 3.0 parts by weight of a polyfunctional isocyanate (MR-100 manufactured by Nippon Polyurethane Co., Ltd., solid content concentration of 30% by weight) (20% by weight) Wt.%) And acrylate (A-
TMM-3L) (1.1 parts by weight (10% by weight)), 0.55 parts by weight of u- CAT (manufactured by Sun Abbot Co.) and 0.4 parts by weight of ethyl acetate were added and mixed to obtain an adhesive composition. Thickness as substrate
Using a 125 μm polyethylene terephthalate film (E-5000 manufactured by Toyobo Co., Ltd.), the above adhesive composition was applied thereon and dried at 115 ° C. to form an adhesive layer. The thickness of the obtained adhesive layer was 17 μm.

Preparation of Photosensitive Resin Plate Material Polyethylene terephthalate having a 125 μm-thick polyester cover film coated with a 2 μm-thick polyvinyl alcohol (Nippon Synthetic Chemical Co., Ltd. AH-24) film and the adhesive layer obtained above during the film, the photosensitive resin in contact with the polyvinyl alcohol coating was placed, 105 ° C. in a heat press at a pressure of 100 kg / cm ^2, a photosensitive resin plate having a thickness of 2.8mm hot pressed for 1 minute Materials were produced.

Development of photosensitive resin plate material The uppermost polyester cover film of the obtained photosensitive resin plate material was peeled off, leaving a polyvinyl alcohol film on the photosensitive resin layer. Next, a negative film having an image was brought into close contact with the above-mentioned printing plate material, and exposed for 5 minutes at an illuminance of 25 W / m ² using a mercury lamp (manufactured by Dainippon Screen). After the exposure, the negative film was removed, and development was carried out with a brush using neutral water containing 2% by weight of sodium alkylnaphthalenesulfonate at 40 ° C. for 15 minutes to obtain an image pattern having a relief depth of 1.2 mm. This image pattern accurately reproduced the image of the negative film used. This was post-exposed at 60 ° C. for 20 minutes to obtain a printing plate.

The photo-cured photosensitive resin layer and the substrate polyethylene terephthalate film were firmly adhered. When printing was performed by a flexographic printing machine using this printing plate, the adhesive layer showed the same adhesiveness before and after printing, and the relief did not peel off, and good printing was performed.

Example 2 A polyethylene terephthalate film coated with the adhesive layer obtained in Example 1 was heated at 50 ° C.
After being left in the constant temperature chamber for 2 weeks, a photosensitive resin plate material was produced in the same manner as in Example 1 using the same photosensitive resin as in Example 1. The adhesiveness between the base material of the obtained photosensitive resin plate material and the photosensitive resin layer was excellent without any difference from Example 1. Using this photosensitive resin plate material, a printing plate was prepared in the same manner as in Example 1, and printing was performed using this printing plate. As a result, good printing was achieved.

Example 3 18.7 parts by weight (70% by weight) of a copolymerized polyester (Vylon RV-30SS manufactured by Toyobo Co., Ltd.) and a copolymerized polyester (Vylon RV-2 manufactured by Toyobo Co., Ltd.)
0SS) A mixture of 8.0 parts by weight (30% by weight), 2.0 parts by weight of a polyfunctional isocyanate (MR-400 manufactured by Nippon Polyurethane Co., Ltd.), 1.5 parts of 2-hydroxy-1,3-dimethacryloioxypropane
By weight, 0.55 parts by weight of a catalyst (Sun-Abbott Co., Ltd. U-CAT) and 1.0 part by weight of ethyl acetate were mixed to obtain an adhesive composition.

Using this adhesive composition, a photosensitive resin plate material was prepared in the same manner as in Example 1 except that the thickness of the adhesive layer was changed to 15 μm. The adhesiveness between the base material of the obtained photosensitive resin plate material and the photosensitive resin layer was excellent without any difference from Example 1. Using this photosensitive resin plate material, a printing plate was prepared in the same manner as in Example 1, and printing was performed using this printing plate. As a result, good printing was achieved.

(Comparative Example 1) 26.0 parts by weight of copolymerized polyester (Vylon RV-30SS manufactured by Toyobo Co., Ltd.), 3.0 parts by weight of polyfunctional isocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.), catalyst (Nippon Polyurethane Co., Ltd.) 0.51 parts by weight of u-CAT) and 1.5 parts by weight of ethyl acetate were mixed to obtain an adhesive composition.

Using this adhesive composition, a photosensitive resin plate material was prepared in the same manner as in Example 1 except that the thickness of the adhesive layer was changed to 18 μm. However, after creating the adhesive layer
When the adhesive layer was left at 25 ° C. for 5 days or more, the adhesive strength of the adhesive layer to the photosensitive resin was lost and the photosensitive resin layer was peeled off.

(Comparative Example 2) An adhesive composition was obtained in the same manner as in Example 1 except that trimethylol triacrylate was used instead of the acrylate of Example 1, and this was used to form an adhesive layer on a substrate. Was prepared. Immediately after forming the adhesive layer on the substrate, the photosensitive resin layer was pressure-bonded and subjected to plate-making in the same manner as in Example 1 and showed good adhesiveness. However, after leaving the above-mentioned adhesive layer at 25 ° C. for 5 days or more, the photosensitive resin layer is similarly press-bonded, and the resulting photosensitive resin plate material loses its adhesive strength and the photosensitive resin The layers peeled off.
When the peel strength was measured by T-peel measurement (peel speed: 10 mm / min), the peel strength was 0.1 kg / cm or less.

[0082]

According to the present invention, the adhesive force of the adhesive layer to the photosensitive resin layer for water-developable flexographic printing is maintained even after a long time has passed since the formation of the adhesive layer on the base material. It is possible to provide a photosensitive resin plate material in which the photosensitive resin layer does not peel off from the substrate even during development.

Further, since the photosensitive resin layer and the substrate can be firmly bonded in a short time without aging of the adhesive layer, the production efficiency can be improved.

Further, the adhesive strength of the adhesive layer formed on the base material is maintained even after being left for a long time, and is maintained even when exposed to the outside air, which is advantageous in the management and storage of products. Therefore, it is possible to provide a photosensitive resin plate material suitable for water-developable flexographic printing which can provide a stable product with an adhesive force to a support regardless of storage conditions after the production of the adhesive layer.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location G03F 7/027 513 G03F 7/027 513 (56) References JP-A-58-174945 (JP, A JP-A-60-146235 (JP, A) JP-A-62-167383 (JP, A)

Claims (1)

(57) [Claims] 1. A photosensitive resin plate material comprising a photosensitive resin layer for water-developable flexographic printing provided on a substrate through an adhesive layer, wherein the adhesive layer has a glass transition temperature of 10 ° C. or lower. 90 copolymerized polyester
Comprising 50 wt%, the composition containing a compound having a mixture glass transition temperature comprising 50 ° C. or more copolyesters 10 to 50 wt%, and polyfunctional iso shea Aneto, a hydroxyl group and an acryloyl group or a methacryloyl group A photosensitive resin plate material comprising: