JP2010076135A - Resin composition for laser carving, image forming material, relief printing original plate for laser carving, relief printing plate, and method for manufacturing relief printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a resin composition for laser carving which shows high carving sensitivity during laser carving; an image forming material of high carving sensitivity wherein direct plate making is possible by laser carving; a relief printing original plate for laser carving; a method for manufacturing the relief printing plate using the relief printing original plate, and the relief printing plate obtained by the method. <P>SOLUTION: The resin composition for laser carving, which includes two or more ethylenically unsaturated bonds (A), multifunctional polymer composition having carbon-to-sulfur bond and ionic bond at the connection between two of the ethylenically unsaturated bonds, and at least binder polymer (B), is employed for the image forming material, the relief printing original plate for laser carving, the relief printing plate, and the method for manufacturing the relief printing plate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resin composition for laser engraving, an image forming material, a relief printing plate precursor for laser engraving, a relief printing plate, and a method for producing a relief printing plate.

  As a method for forming a printing plate by forming irregularities on a photosensitive resin layer laminated on a surface area of a support, a relief forming layer formed using a photosensitive composition is exposed to ultraviolet light through an original film. A method of selectively curing an image portion and removing an uncured portion with a developer, so-called “analog plate making” is well known.

  The relief printing plate is a relief printing plate having a relief layer having irregularities, and the relief layer having such irregularities includes, for example, an elastomeric polymer such as synthetic rubber, a resin such as a thermoplastic resin, Alternatively, it is obtained by patterning a relief forming layer containing a photosensitive composition containing a mixture of a resin and a plasticizer to form irregularities. Of such relief printing plates, those having a soft relief layer are sometimes referred to as flexographic plates.

  When producing a relief printing plate by analog plate making, since an original image film using a silver salt material is generally required, the production time and cost of the original image film are required. Furthermore, since chemical processing is required for development of the original image film and processing of the development waste liquid is also required, a simpler plate preparation method, for example, a method that does not use the original image film, and development processing are required. The method of not doing is examined.

In recent years, a method of making a relief forming layer by scanning exposure without using an original film has been studied.
As a technique that does not require an original image film, a relief printing plate precursor provided with a laser-sensitive mask layer element capable of forming an image mask on a relief forming layer has been proposed (see, for example, Patent Documents 1 and 2). . According to these plate making methods, since an image mask having the same function as the original film is formed from the mask layer element by laser irradiation based on the image data, it is referred to as “mask CTP method”. A film is not necessary, but the subsequent plate making process is a process of exposing with ultraviolet light through an image mask to develop and remove an uncured portion, and there is still room for improvement in that a development process is required.

Many so-called “direct engraving CTP methods” have been proposed as plate making methods that do not require a development step, in which a relief forming layer is directly engraved with a laser to make a plate. The direct engraving CTP method literally engraves with a laser to form reliefs, and has the advantage that the relief shape can be freely controlled unlike the relief formation using the original film. For this reason, when an image such as a letter is formed, the area is engraved deeper than other areas, or the fine halftone dot image is engraved with a shoulder in consideration of resistance to printing pressure. Is also possible.
However, high energy is required to form a relief having unevenness that can withstand printing pressure on a relief forming layer having a predetermined thickness, and since the speed of laser engraving is slow, compared to a type that forms an image through a mask, There is a problem of low productivity.

  For this reason, attempts have been made to improve the sensitivity of the relief original plate. For example, a flexographic printing plate precursor for laser engraving including an elastomer foam has been proposed (see, for example, Patent Document 3). In this technology, low-density foam is used for the relief forming layer to improve the engraving sensitivity. However, because it is a low-density material, the strength of the printing plate is insufficient and the printing durability is significantly impaired. There is a problem of being.

  Further, for example, Patent Documents 4 to 6 disclose flexographic printing plate precursors capable of laser engraving or flexographic printing plates obtained by laser engraving. In these documents, a monomer is mixed with an elastomeric rubber as a binder, the mixture is cured by a thermal polymerization mechanism or a photopolymerization mechanism, and then laser engraving is performed to obtain a flexographic plate.

The problem that the direct engraving CTP method has is that the speed of laser engraving is low. In the mask CTP method, the thickness of the mask layer element to be ablated is about 1 to 10 μm, whereas in the direct engraving CTP method, it is necessary to engrave at least 100 μm in order to directly form a relief. Because.
Therefore, some proposals for improving the laser engraving sensitivity have been made as follows.

For example, a flexographic printing plate precursor for laser engraving including an elastomer foam has been proposed (see, for example, Patent Document 7). In this technology, the engraving sensitivity is improved by using a foam having a low density. However, since it is a low-density material, the strength as a printing plate is insufficient and the printing durability is significantly impaired. is there.
For example, a flexographic printing plate precursor for laser engraving containing a microsphere encapsulating a hydrocarbon gas has been proposed (see, for example, Patent Document 8). In this technology, the gas in the microspheres expands due to the heat generated by the laser, and the engraving sensitivity is improved by a system that collapses the material to be engraved. There is a problem that the strength tends to be insufficient. In addition, gas is more easily expanded by heat than solids, and even if a microsphere with a high thermal deformation start temperature is selected, volume changes due to changes in external temperature cannot be avoided. However, it is not suitable to use a material containing air bubbles in a printing plate that requires the above.
For example, a resin relief printing plate for laser engraving containing a polymer filler having a ceiling temperature of less than 600 degrees K has been proposed (see, for example, Patent Document 9). In this technology, the engraving sensitivity is improved by adding a polymer filler having a low depolymerization temperature. However, when such a polymer filler is used, the surface of the printing plate precursor is uneven, There is a problem of seriously affecting print quality.

As described above, various techniques have been proposed for the resin composition that can be suitably used for the relief forming layer of the relief printing plate precursor for laser engraving, but those having high engraving sensitivity when subjected to laser engraving The current situation is not yet provided.
Japanese Patent No. 2773847 JP-A-9-171247 JP 2002-357907 A Japanese Patent No. 2846954 JP 11-338139 A JP-A-11-170718 JP 2000-318330 A US Patent Application Publication No. 2003/180636 JP 2000-168253 A

This invention makes it a subject to achieve the following objectives.
That is, an object of the present invention is to provide a resin composition for laser engraving having high engraving sensitivity when subjected to laser engraving.
Another object of the present invention is to provide an image forming material having high engraving sensitivity and capable of direct plate making by laser engraving, a relief printing plate precursor for laser engraving, and a method for producing a relief printing plate using the relief printing plate precursor And a relief printing plate obtained by the production method.

  Means for solving the above-mentioned problems are as follows.

<1> (A) A polyfunctional polymerizable compound having two or more ethylenically unsaturated bonds, a carbon-sulfur bond and an ionic bond at a site connecting two ethylenically unsaturated bonds, and (B) A resin composition for laser engraving containing at least a binder polymer.
<2> In the (A) polyfunctional polymerizable compound, the carbon-sulfur bond is —C—S—, —C—SS—, —NH (C═S) O—, —NH (C═O) S. The resin composition for laser engraving according to <1>, wherein the resin composition is at least one unit selected from —, —NH (C═S) S—, and —C—SO ₂ —.

<3> In the (A) a polyfunctional polymerizable compound, ionic _{^{bond, * -CO-O -, *}} -SO 2 -O -, * -PO 3 -, and represented by the following general formula (1) <1> or <2> comprising one type of anion moiety selected from the structure and one type of cation moiety selected from the structures represented by the following general formulas (2) to (4): Resin composition for laser engraving.

In the general formulas (1) to (4), R ^{1 to} R ⁸ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an alkoxy group, an aryl group, or a heterocyclic group. And at least two of R ^{2 to} R ⁴ may be linked to form a ring, at least two of R ^{5 to} R ⁷ may be linked to form a ring, and R ⁸ and R ⁹ may be They may be linked to form a ring.

  <4> In the (A) polyfunctional polymerizable compound, at least one of the partial structures containing the ethylenically unsaturated bond is a partial structure represented by any one of the following general formulas (5) to (7). The resin composition for laser engraving according to any one of <1> to <3>.

In the general formulas (5) to (7), R ^{10 to} R ²⁰ each independently represent a hydrogen atom or a monovalent substituent, and X, Y, and Z each independently represent an oxygen atom, A sulfur atom, — (N—R ²¹ ) —, and a sulfonyl group, and R ²¹ represents a hydrogen atom or a monovalent organic group.

<5> (C) The resin composition for laser engraving according to any one of <1> to <4>, further including a photothermal conversion agent capable of absorbing light having a wavelength of 700 nm to 1300 nm.
<6> The resin composition for laser engraving according to any one of <1> to <5>, which is cured by at least one of light and heat.
<7> The resin composition for laser engraving according to any one of <1> to <6>, which is cured by heat.

<8> An image forming material having an image forming layer made of the resin composition for laser engraving according to any one of <1> to <7> on a support.
<9> The image forming material according to <8>, wherein the image forming layer is cured by at least one of light and heat.

<10> A relief printing plate precursor for laser engraving having a relief forming layer comprising the resin composition for laser engraving according to any one of <1> to <7>.
<11> (1) Step of crosslinking the relief forming layer in the relief printing plate precursor for laser engraving according to <10> by at least one of light and heat, and (2) Laser engraving of the crosslinked relief forming layer And forming a relief layer, a method for producing a relief printing plate.
<12> The method for producing a relief printing plate according to <11>, wherein the step (1) is a step of crosslinking the relief forming layer with heat.

<13> A relief printing plate having a relief layer, produced by the method for producing a relief printing plate according to <11> or <12>.
<14> The relief printing plate according to <13>, wherein the relief layer has a thickness of 0.05 mm to 10 mm.
<15> The relief printing plate according to <13> or <14>, wherein the relief layer has a Shore A hardness of 50 ° or more and 90 ° or less.

According to the present invention, a resin composition for laser engraving having high engraving sensitivity when subjected to laser engraving can be provided.
Further, according to the present invention, an image forming material having high engraving sensitivity and capable of direct plate making by laser engraving, a relief printing plate precursor for laser engraving, a method for producing a relief printing plate using the relief printing plate precursor, and A relief printing plate obtained by the production method can be provided.

  Hereinafter, the resin composition for laser engraving, the image forming material, the relief printing plate precursor for laser engraving, the relief printing plate, and the method for producing the relief printing plate of the present invention will be described in detail.

[Resin composition for laser engraving]
The resin composition for laser engraving of the present invention has (A) two or more ethylenically unsaturated bonds, and a carbon-sulfur bond and an ionic bond are formed at a site connecting two ethylenically unsaturated bonds. It contains at least a polyfunctional polymerizable compound having (B) a binder polymer.
Hereinafter, the resin composition for laser engraving of the present invention is also simply referred to as “resin composition of the present invention”.

  Since the resin composition of the present invention has high engraving sensitivity when subjected to laser engraving, laser engraving can be performed at a high speed, and therefore engraving time can be shortened. The resin composition of the present invention having such characteristics can be applied to a wide range of applications for forming a resin molded article subjected to laser engraving without any particular limitation. For example, as an application mode of the resin composition of the present invention, specifically, an image forming layer of an image forming material that forms an image by laser engraving, a relief forming layer of a printing plate precursor that forms a convex relief by laser engraving , Intaglio, stencil, stamp, and the like, but are not limited thereto. The resin composition of the present invention can be particularly suitably used for an image forming layer of an image forming material for forming an image by laser engraving and a relief forming layer in a relief printing plate precursor for laser engraving. Hereinafter, the components of the resin composition for laser engraving will be described.

<(A) Polyfunctional polymerizable compound having two or more ethylenically unsaturated bonds, and having a carbon-sulfur bond and an ionic bond at a site connecting two ethylenically unsaturated bonds>
The resin composition of the present invention is (A) a polyfunctional compound having two or more ethylenically unsaturated bonds, and having a carbon-sulfur bond and an ionic bond at a site connecting two ethylenically unsaturated bonds. A polymerizable compound (hereinafter referred to as “a sulfur-containing polyfunctional monomer” as appropriate) is contained.

Specific examples of the functional group containing a carbon-sulfur bond include sulfide, disulfide, sulfoxide, sulfonyl, sulfonamide, thiocarbonyl, thiocarboxylic acid, dithiocarboxylic acid, sulfamic acid, thioamide, thiocarbamate, dithiocarbamate, or thiol. Examples include functional groups containing urea.
From the viewpoint of engraving sensitivity, a functional group containing disulfide, thiocarbamate, or dithiocarbamate is preferred, and a functional group containing disulfide is more preferred.
Moreover, in a sulfur-containing polyfunctional monomer, as a coupling group containing a carbon-sulfur bond that links two ethylenically unsaturated bonds, more specifically, —C—S—, —C—SS—, — It is preferably at least one unit selected from NH (C═S) O—, —NH (C═O) S—, —NH (C═S) S—, and —C—SO ₂ —. Among these, -C-SS-, -NH (C = S) O-, -NH (C = O) S-, and -NH (C = S) S- are preferable from the viewpoint of increasing engraving sensitivity. C-SS- is most preferred.

As the ionic bond in the sulfur-containing polyfunctional monomer in the present invention, any ion bond may be used as long as it is an ionic bond comprising an anion portion having a binding site with an adjacent atom and a cation portion having a binding site with an adjacent atom. It may be a thing.
The ionic bond is preferably composed of a monovalent anion portion and a monovalent cation portion from the viewpoint of thermal stability.
For ionic bonding, more specifically, in terms of raw material procurement and thermal _{^{stability, * -CO-O -, *}} -SO 2 -O -, * -PO 3 -, and the following general formula (1) It is preferable to consist of 1 type of anion part selected from the structure represented, and 1 type of cation part selected from the structure represented by following General formula (2)-(4).
Here, “*” in the anion portion and the cation portion represents a binding site between an ionic bond and an adjacent atom.

In the general formulas (1) to (4), R ^{1 to} R ⁸ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an alkoxy group, an aryl group, or a heterocyclic group. To express.

The alkyl group or alkoxy group represented by R ^{1 to} R ⁸ may be linear or branched, preferably has 1 to 12 carbon atoms, more preferably has 1 to 8 carbon atoms, and carbon Those having 1 to 4 atoms are more preferred.
The alkenyl group or alkynyl group represented by R ^{1 to} R ⁸ may be linear or branched, preferably has 2 to 12 carbon atoms, and more preferably has 2 to 8 carbon atoms. More preferred are those having 2 to 4 carbon atoms.
Cycloalkyl group: The ring may be condensed. The number of carbon atoms is preferably 5 to 12, more preferably 5 to 10, and still more preferably 5 to 8.

The aryl group represented by R ^{1 to} R ⁸ may be condensed, preferably has 6 to 18 carbon atoms, more preferably has 6 to 14 carbon atoms, and more preferably has 6 to 10 carbon atoms. Are more preferred.
In addition, the heterocyclic group represented by R ^{1 to} R ⁸ may be condensed, and preferably includes any of a sulfur atom, a nitrogen atom, and an oxygen atom, and more preferably includes a nitrogen atom. 3-10 are preferable, as for this heterocyclic group, 3-8 are more preferable, and 3-6 are still more preferable.

Each group represented by R ^{1 to} R ⁸ may further have a substituent, and examples of the substituent include a halogen atom, a nitro group, a cyano group, a hydroxy group, a thiol group, an amide group, and a formyl group. Carbonyl group, ester group, ether, thioether, alkyl group, alkenyl group, cycloalkyl group, alkoxy group, aryl group, or heterocyclic group. The preferred embodiments of the alkyl group, alkenyl group, cycloalkyl group, alkoxy group, aryl group, or heterocyclic group listed here are alkyl groups, alkenyl groups, cycloalkyl groups represented by R ^{1 to} R ⁸ , It is the same as the alkoxy group, aryl group, or heterocyclic group.
In the present invention, each group represented by R ^{1 to} R ⁸ is preferably unsubstituted or has a methyl group, an ethyl group, a methoxy group, an ethoxy group, or a phenyl group as a substituent.

In the general formulas (1) to (4), at least two of R ^{2 to} R ⁴ may be connected to form a ring, or at least two of R ^{5 to} R ⁷ may be connected to form a ring. R ⁸ and R ⁹ may be linked to form a ring. As a structure of the ring formed, a 3-10 membered ring is preferable, a 4-8 membered ring is more preferable, and a 5-6 membered ring is still more preferable. Further, the ring formed may be saturated or unsaturated, or may be condensed. Furthermore, the connecting chain for forming a ring may contain a nitrogen atom, an oxygen atom, or a sulfur atom.

Among them, from the viewpoint of raw material procurement properties, preferably anion ^{portion, * -CO-O -, *} -SO 2 -O - , more preferably ^an, * -CO-O ^- a.
Moreover, from a viewpoint of raw material cost and thermal stability, a preferable cation part is a structure represented by the said General formula (2).
Here, the anion portion constituting the ionic bonds ^* -SO ₂ -O ^- in the case of sulfur-containing anion such as a carbon of the sulfur-containing polyfunctional monomer in the carbon atoms adjacent to the sulfur-containing anion -A sulfur bond may be formed.

The number of sulfur atoms contained in the molecule of the sulfur-containing polyfunctional monomer is not particularly limited as long as it is 1 or more, and can be appropriately selected according to the purpose, but the balance between engraving sensitivity and solubility in the coating solvent. From the viewpoint, 1 to 10 is preferable, 1 to 5 is more preferable, and 1 to 2 is more preferable.
The number of ionic bonds contained in the molecule of the sulfur-containing polyfunctional monomer is not particularly limited as long as it is 1 or more, and from the viewpoint of the balance of engraving sensitivity and solubility in the coating solvent, 1 to 10 is preferable, 1 to 5 is more preferable, and 1 to 2 is more preferable.
On the other hand, the number of ethylenically unsaturated sites contained in the molecule is not particularly limited as long as it is 2 or more, and can be appropriately selected according to the purpose. -10 are preferable, 2-6 are more preferable, and 2-4 are still more preferable.

In the sulfur-containing polyfunctional monomer, at least one of the partial structures containing an ethylenically unsaturated bond is a partial structure represented by any one of the following general formulas (5) to (7) from the viewpoint of decomposability of the polymer. It is preferable that
In the sulfur-containing polyfunctional monomer in the present invention, two or more of the same types of partial structures of the following general formulas (5) to (7) may be present in one molecule, or different types. Two or more things may exist.
Here, “*” in any partial structure of the general formulas (5) to (7) represents a bonding site with an adjacent atom.

In general formulas (5) to (7), R ^{10 to} R ²⁰ each independently represent a hydrogen atom or a monovalent substituent. X, Y, and Z each independently represent an oxygen atom, a sulfur atom, —N—R ²¹ —, or a sulfonyl group. Here, R ²¹ represents a hydrogen atom or a monovalent organic group.

In the general formula (5), R ^{10 to} R ¹² each independently represent a hydrogen atom or a monovalent substituent.
Examples of R ¹⁰ include a hydrogen atom or an organic group such as an alkyl group which may have a substituent. Specifically, a hydrogen atom, a methyl group, a methylalkoxy group, or a methyl ester group is particularly preferable.
R ¹¹ and R ¹² may each independently have a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or a substituent. A good alkyl group, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like are mentioned. Among them, a hydrogen atom, a carboxyl group, alkoxycarbonyl A group, an alkyl group which may have a substituent, and an aryl group which may have a substituent are preferable. Here, examples of the substituent that can be introduced into these groups include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropyloxycarbonyl group, a methyl group, an ethyl group, and a phenyl group.
X is preferably an oxygen atom, a sulfur atom, or —N—R ²¹ —, and examples of R ²¹ include an alkyl group which may have a substituent.

In the general formula (6), R ^{13 to} R ¹⁷ each independently represent a hydrogen atom or a monovalent substituent.
Examples of R ^{13 to} R ¹⁷ include a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, and an alkyl group that may have a substituent, An aryl group that may have a substituent, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent. An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferred. Here, examples of the substituent that can be introduced into these groups include those exemplified as the substituent that can be introduced in the general formula (5).
Y is preferably an oxygen atom, a sulfur atom, or —N—R ²¹ —, and examples of R ²¹ include the same as those in General Formula (5).

In the general formula (7), R ^{18 to} R ²⁰ each independently represents a hydrogen atom or a monovalent substituent.
Specific examples of R ^{18 to} R ²⁰ include a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, and a substituent. An alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent , An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, etc., among which a hydrogen atom, a carboxyl group, an alkoxy A carbonyl group, an alkyl group which may have a substituent, and an aryl group which may have a substituent are preferable. Here, examples of the substituent that can be introduced into these groups include those exemplified as the substituent that can be introduced in the general formula (5).
Z is preferably an oxygen atom, a sulfur atom, or —N—R ²¹ —, and examples of R ²¹ include the same as those in General Formula (5).

  Among the partial structures represented by the general formulas (5) to (7), the partial structure described in the general formula (5) is preferable from the viewpoint of easy crosslinking by heat or light.

Moreover, the sulfur-containing polyfunctional monomer in the present invention includes a linking group L for linking the ethylenically unsaturated sites. Here, the linking group L represents a divalent or higher valent linking group containing a carbon-sulfur bond and an ionic bond.
Examples of the functional group having a carbon-sulfur bond contained in the linking group L include sulfide, disulfide, sulfoxide, sulfonyl, sulfonamide, thiocarbonyl, thiocarboxylic acid, dithiocarboxylic acid, sulfamic acid, thioamide, thiocarbamate, dithiocarbamate, or Examples include functional groups containing thiourea. From the viewpoint of engraving sensitivity, a functional group containing disulfide, thiocarbamate, or dithiocarbamate is preferred, and a functional group containing disulfide is more preferred.
In addition, the ionic bond in the linking group L is included as an atomic group constituting the ionic bond (that is, an atomic group composed of an anion portion and a cation portion). As this atomic group, ^* —CO—O ^{− _{, * -SO 2 -O -, *}} -PO 3 -, and tables in a one anionic portion, wherein the general formula (2) to (4) is selected from the structures represented by the general formula (1) An atomic group consisting of one kind of cation moiety selected from the structures to be formed is preferable.

  In addition, the linking group L preferably contains a hydrocarbon group in addition to the functional group having a carbon-sulfur bond and the atomic group constituting the ionic bond, and in particular, the total number of carbon atoms is 1 to 10. Is more preferable. Among them, the linking group L is composed of a plurality of hydrocarbon groups having 1 to 6 carbon atoms, or the plurality of hydrocarbon groups having 1 to 6 carbon atoms has a structure other than a hydrocarbon group such as an ester bond. It is preferable to include what was connected via the. As a hydrocarbon group, a C1-C6 alkylene group, a phenylene group, etc. are preferable. Examples of the structure other than the hydrocarbon group constituting the linking group L include an ester bond, an amide bond, a urea bond, a urethane bond, an ether bond, a carbonyl group, a sulfonyl group, and the like. Most preferred. The hydrocarbon group may be appropriately substituted with a monovalent substituent, and a hydroxyl group, thiol group, amino group, carboxyl group, cyano group, nitro group, or the like is preferably used as the substituent. In particular, the hydrocarbon group constituting the linking group L is preferably a hydrocarbon group substituted with a hydroxyl group. The linking group L preferably has a structure containing 1 to 5 hydrocarbon groups per one ethylenically unsaturated bond.

Specific preferred examples of the sulfur-containing polyfunctional monomer having a partial structure represented by any one of the general formulas (5) to (7) are shown below, but the present invention is not limited thereto.
Moreover, R in the following specific examples represents a hydrogen atom or a methyl group, and these may be the same or different.

  The sulfur-containing polyfunctional monomer in the present invention includes (a) a compound containing a sulfur atom and having two or more carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups, and an amine having an ethylenically unsaturated bond site. (B) neutralization reaction between (b) a compound containing a sulfur atom and having two or more amino groups and a carboxylic acid, sulfonic acid or phosphoric acid having an ethylenically unsaturated bond site, (c) a sulfur atom And a neutralization reaction of a carboxylic acid, sulfonic acid or phosphoric acid having an ethylenically unsaturated bond with an amine having an ethylenically unsaturated bond, (d) a carboxylic acid having an ethylenically unsaturated bond, a sulfonic acid, Or a neutralization reaction between phosphoric acid and an amine containing a sulfur atom and having an ethylenically unsaturated bond, (e) containing a sulfur atom and having two or more ammonium groups, sulfonium groups, and phosphonium groups An ion exchange reaction between a salt of the compound and a metal salt of a carboxylic acid, sulfonic acid or phosphoric acid having an ethylenically unsaturated bond; (f) a salt of the compound having two or more ammonium groups, sulfonium groups and phosphonium groups; And an ion exchange reaction with a metal salt of a carboxylic acid, a sulfonic acid, or a phosphoric acid containing a sulfur atom and having an ethylenically unsaturated bond. Moreover, you may use a commercial item.

  The molecular weight of the sulfur-containing polyfunctional monomer in the present invention is preferably 120 to 3000, more preferably 120 to 1500, from the viewpoint of the flexibility of the formed film.

  Moreover, although the sulfur-containing polyfunctional monomer in this invention may be used independently, you may use it as a mixture with the polyfunctional polymerizable compound and monofunctional polymerizable compound which do not have a sulfur atom in a molecule | numerator. From the viewpoint of engraving sensitivity, it is preferable to use a sulfur-containing polyfunctional monomer alone or as a mixture of a sulfur-containing polyfunctional monomer and a monofunctional ethylenic monomer, more preferably a sulfur-containing polyfunctional monomer and a monofunctional. This is an embodiment used as a mixture with an ethylenic monomer.

In the resin composition of the present invention, film properties such as brittleness and flexibility can be adjusted by using a polymerizable compound including a sulfur-containing polyfunctional monomer.
In addition, the total content of polymerizable compounds including the sulfur-containing polyfunctional monomer in the resin composition of the present invention is based on the non-volatile components in the composition from the viewpoint of flexibility and brittleness of the crosslinked film. 10 mass%-60 mass% are preferable, and the range of 15 mass%-40 mass% is more preferable.
In addition, when using together a sulfur-containing polyfunctional monomer and another polymeric compound, 5 mass% or more is preferable and, as for the quantity of the sulfur-containing polyfunctional monomer in all the polymeric compounds, 10 mass% or more is more preferable.

  In the present invention, a polymerizable compound having no sulfur atom in the molecule that can be used in combination with the sulfur-containing polyfunctional monomer (hereinafter simply referred to as “polyfunctional monomer”) has two terminal ethylenically unsaturated bonds. It is preferably selected from compounds having ˜20. Such a compound group is widely known in this industrial field, and in the present invention, these can be used without any particular limitation. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or copolymers thereof, and mixtures thereof. Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. In addition, unsaturated carboxylic acid ester having a nucleophilic substituent such as hydroxyl group or amino group, amide and monofunctional or polyfunctional isocyanate, addition reaction product of epoxy, monofunctional or polyfunctional carboxylic acid A dehydration condensation reaction product with an acid or the like is also preferably used. In addition, unsaturated carboxylic acid esters having an electrophilic substituent such as isocyanato group, epoxy group, amides with monofunctional or polyfunctional alcohols, addition reaction products of amines, halogen groups, tosyloxy A substitution reaction product of an unsaturated carboxylic acid ester or amide with a monofunctional or polyfunctional alcohol or amine having a leaving substituent such as a group is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of monomers of esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.

  Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetracrotonate.

  Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.

  Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, Those having an aromatic skeleton described in JP-A-59-5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used.

  The ester monomers can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, and 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like.

  Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (i) to a polyisocyanate compound having two or more isocyanate groups. Compounds and the like.

_{CH 2 = C (R) COOCH} 2 CH (R ') OH (i)
(However, R and R ′ each represent H or CH _3. )

  Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable.

  Further, by using addition polymerizable compounds having an amino structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238, a short time can be obtained. A cured composition can be obtained.

  Other examples include reacting polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490. And polyfunctional acrylates and methacrylates such as epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid compounds described in JP-A-2-25493 are also included. be able to. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, the Japan Adhesion Association magazine vol. 20, No. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

  In the present invention, the monofunctional polymerizable compound (hereinafter simply referred to as “monofunctional monomer”) that can be used in combination with the sulfur-containing polyfunctional monomer is selected from compounds having one terminal ethylenically unsaturated bond. Such a compound group is widely known in this industrial field, and in the present invention, these can be used without any particular limitation. Examples of monofunctional monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof. An ester of a saturated carboxylic acid and a monofunctional alcohol compound, or an amide of an unsaturated carboxylic acid and a monofunctional aliphatic amine compound is used. Also, unsaturated carboxylic acid ester having nucleophilic substituent such as hydroxyl group, amino group, mercapto group, amide and monofunctional isocyanate, addition reaction product of epoxy, dehydration with monofunctional carboxylic acid A condensation reaction product or the like is also preferably used. In addition, unsaturated carboxylic acid esters having an electrophilic substituent such as an isocyanato group or an epoxy group, addition products of amides with monofunctional alcohols, amines, thiols, halogen groups, and tosyloxy groups A substitution reaction product of an unsaturated carboxylic acid ester having a leaving substituent such as amide, amides with monofunctional alcohols, amines or thiols is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of a monofunctional aliphatic alcohol compound and an unsaturated carboxylic acid include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (Meth) acrylate having a hydroxyl group such as 3-chloro-2-hydroxypropyl (meth) acrylate, β-hydroxy-β ′-(meth) acryloyloxyethyl phthalate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl Alkyl (meth) acrylates such as (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, Cycloalkyl (meth) acrylates such as xyl (meth) acrylate, chloroethyl (meth) acrylate, halogenated alkyl (meth) acrylates such as chloropropyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, Alkoxyalkyl (meth) acrylates such as butoxyethyl (meth) acrylate, phenoxyethyl acrylate, phenoxyalkyl (meth) acrylates such as nonylphenoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate , Methoxydipropylene glycol (meth) acrylate, alkoxyalkylene glycol (meth) acrylate, and the like.

  Specific examples of amide monomers of monofunctional aliphatic amine compounds and unsaturated carboxylic acids are (meth) acrylamides such as (meth) acrylamide, diacetone (meth) acrylamide, and N, N′-methylenebis (meth) acrylamide. Acrylamides, 2,2-dimethylaminoethyl (meth) acrylate, 2,2-diethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, etc. There is.

The resin composition of the present invention is characterized by containing a sulfur-containing polyfunctional monomer as described above, and has an effect of being excellent in engraving sensitivity.
The sulfur-containing polyfunctional monomer in the present invention has both a carbon-sulfur bond having a bond dissociation energy smaller than a carbon-carbon bond and an ionic bond having a bond dissociation energy smaller than a covalent bond in the molecule. Yes. Such a sulfur-containing polyfunctional monomer is crosslinked by light and / or heat. When the obtained crosslinked product is thermally decomposed, a monomer having a carbon-carbon bond instead of a carbon-sulfur bond, or an ion Compared to a monomer having a covalent bond instead of a bond, the carbon-sulfur bond and the ionic bond are cleaved at a lower temperature. Thus, in the sulfur-containing polyfunctional monomer, since the crosslinked product obtained from the monomer has low-temperature thermal decomposition characteristics, the crosslinked product is irradiated with a laser to dissipate or scatter the irradiated portion. It is presumed that the engraving sensitivity can be increased when it is subjected to laser engraving.

In addition to (A) a sulfur-containing polyfunctional monomer and (B) binder polymer described later, the resin composition of the present invention is (C) photothermal conversion capable of absorbing light with a wavelength of 700 nm to 1300 nm in order to correspond to an infrared laser. It is a preferable embodiment to contain an agent (hereinafter, sometimes simply referred to as “photothermal conversion agent”).
Laser engraving using a near-infrared laser corresponding to the resin composition of such an embodiment is (1) (C) light absorption by a photothermal conversion agent → (2) (C) photothermal conversion by a photothermal conversion agent → ( 3) Heat transfer from photothermal conversion agent to (B) binder polymer and / or (A) cross-linked product (polymer) of sulfur-containing polyfunctional monomer → (4) Binder and / or (A) sulfur-containing Thermal decomposition of cross-linked product (polymer) of polyfunctional monomer → (5) Dissipation and scattering of (B) decomposed (B) binder polymer and / or (A) cross-linked product (polymer) of sulfur-containing polyfunctional monomer It is thought to consist of processes.
Here, since the sulfur-containing polyfunctional monomer (A) has low-temperature pyrolysis characteristics as described above, the effect of promoting thermal decomposition in the process of (4) by the low-temperature pyrolysis characteristics. Therefore, it is considered that the laser engraving sensitivity is very high. In particular, this effect is great when a sulfur-containing polyfunctional monomer having a C—SS bond, —NH—C (═O) —S— bond, or —NH—C (═S) —S— bond is used. This is presumably because the bond dissociation energy of SS bond, C (═O) —S bond, and C (═S) —S bond is smaller than that of C—S—C bond. In particular, this effect is remarkable in the case of the C-SS bond.

  In the resin composition of the present invention, (B) the binder polymer to be combined with (A) the sulfur-containing polyfunctional monomer will be described later. In the case of a poly (hydroxycarboxylic acid) ester such as polylactic acid, the engraving sensitivity improvement effect Is remarkable. This is because, in the process of (4), (B) the nucleophilic site generated when the binder polymer is thermally decomposed is (A) a nucleophilic attack on the cross-linked product (polymer) of the sulfur-containing polyfunctional monomer. This is presumed to promote the decomposition of the crosslinked product. Further, in the process of (4), when (B) a binder polymer that is easily depolymerized is used, it is decomposed into finer fragments. It is considered that the sculpture sensitivity is improved and the engraving sensitivity is improved.

  Hereinafter, (B) binder polymer, which is an essential component of the resin composition of the present invention, and (C) a photothermal conversion agent capable of absorbing light having a wavelength of 700 nm to 1300 nm, a polymerization initiator, etc., which are optional components, explain.

<(B) Binder polymer>
The resin composition for laser engraving of the present invention contains (B) a binder polymer.
The binder polymer is a main component contained in the resin composition for laser engraving, and usually a thermoplastic resin, a thermoplastic elastomer, or the like is used according to the purpose.
For example, from the viewpoint of laser engraving sensitivity, a polymer containing a partial structure that is thermally decomposed by exposure or heating is preferable.
For example, when the purpose is to form a soft and flexible film, a soft resin or a thermoplastic elastomer is selected.
Furthermore, if the resin composition for laser engraving is applied to the relief forming layer in the relief printing plate precursor for laser engraving, the ease of preparation of the composition for the relief forming layer, the oil-based ink in the resulting relief printing plate From the viewpoint of improving the resistance to water, it is preferable to use a hydrophilic or alcoholic polymer.
In addition, for example, when used for the purpose of curing by heating or exposure and improving the strength, a polymer having a carbon-carbon unsaturated bond in the molecule is selected as the binder polymer.
Thus, considering the physical properties according to the application application of the resin composition for laser engraving, selecting a binder polymer according to the purpose, and using one kind of the binder polymer or a combination of two or more kinds. it can.
Hereinafter, various polymers that can be used as the binder polymer in the present invention will be described.

(Degradable polymer)
Examples of the binder polymer that is preferably used from the viewpoint of laser engraving sensitivity include polymers having a partial structure that decomposes upon application of energy such as exposure and heating (polymer having decomposability).

  Examples of degradable polymers include styrene, α-methylstyrene, α-methoxystyrene, acrylic esters, methacrylic esters, and esters other than the above as monomer units having a partial structure that is easily decomposed and cleaved in the molecular chain. Examples include polymers containing compounds, ether compounds, nitro compounds, carbonate compounds, carbamoyl compounds, hemiacetal ester compounds, oxyethylene compounds, aliphatic cyclic compounds, and the like.

Among these, in particular, polyethers such as polyethylene glycol, polypropylene glycol, polytetraethylene glycol, aliphatic polycarbonates, aliphatic carbamates, polymethyl methacrylate, polystyrene, nitrocellulose, polyoxyethylene, polynorbornene, polycyclohexane. A polymer having a molecular structure such as a hydrogenated hexadiene or a dendrimer having many branched structures is preferred from the viewpoint of degradability.
A polymer containing a large number of oxygen atoms in the molecular chain is preferred from the viewpoint of degradability. From such a viewpoint, a compound having a carbonate group, a carbamate group, or a methacryl group in the polymer main chain is preferable.
For example, polyesters and polyurethanes synthesized from (poly) carbonate diol or (poly) carbonate dicarboxylic acid as raw materials, polyamides synthesized from (poly) carbonate diamine as raw materials, and the like can be cited as examples of polymers having good thermal decomposability. . These polymers may contain a polymerizable unsaturated group in the main chain and side chain. In particular, when it has a reactive functional group such as a hydroxyl group, an amino group, or a carboxyl group, it is easy to introduce a polymerizable unsaturated group into such a thermally decomposable polymer.

  Moreover, polyester which consists of hydroxyl carboxylic acid units, such as polylactic acid, can be used as a polymer which has decomposability | degradability. Specific examples of such polyesters include polyhydroxyalkanoate (PHA), lactic acid-based polymer, polyglycolic acid (PGA), polycaprolactone (PCL), poly (butylene succinic acid), and derivatives or mixtures thereof. Those selected from the group consisting of are preferred.

(Thermoplastic polymer)
One of the binder polymers preferably used from the viewpoint of laser engraving sensitivity is a thermoplastic polymer.
The thermoplastic polymer may be an elastomer or a non-elastomeric resin, and may be selected according to the purpose of the resin composition for laser engraving of the present invention.
Examples of the thermoplastic elastomer include urethane-based thermoplastic elastomers, ester-based thermoplastic elastomers, amide-based thermoplastic elastomers, and silicone-based thermoplastic elastomers. For the purpose of improving the laser engraving sensitivity of these thermoplastic elastomers, those obtained by introducing an easily decomposable functional group such as a carbamoyl group or a carbonate group into the main chain of the elastomer can also be used. Moreover, you may mix and use a thermoplastic polymer and the said thermodegradable polymer.
Thermoplastic elastomer is a material that exhibits rubber elasticity at room temperature, and its molecular structure consists of a soft segment such as polyether or rubber molecule, and a hard segment that prevents plastic deformation at around room temperature, just like vulcanized rubber, There are various types of hard segments such as a frozen phase, a crystalline phase, hydrogen bonding, and ionic crosslinking. Such a thermoplastic elastomer is suitable when the resin composition for laser engraving of the present invention is applied to the production of a relief printing plate that requires flexibility, such as a flexographic plate.

  The type of thermoplastic elastomer is selected according to the purpose.For example, when solvent resistance is required, urethane type, ester type, amide type, fluorine type thermoplastic elastomer is preferable, and when heat resistance is required, Urethane-based, olefin-based, ester-based, and fluorine-based thermoplastic elastomers are preferred. Moreover, the hardness of the film | membrane formed with a resin composition can be changed greatly by selecting the kind of thermoplastic elastomer.

  Non-elastomeric resins include, for example, polyester resin, unsaturated polyester resin, polyamide resin, polyamideimide resin, polyurethane resin, unsaturated polyurethane resin, polysulfone resin, polyethersulfone resin, polyimide resin, polycarbonate resin, wholly aromatic Mention may be made of polyester resins and hydrophilic polymers containing hydroxyethylene units (for example polyvinyl alcohol derivatives).

(Hydrophilic or alcoholic polymer)
As the binder polymer used in the present invention, a hydrophilic polymer or an alcoholic polymer is preferable from the viewpoint of removal of residue after engraving. Specific examples of the hydrophilic polymer include those described later. Among these, a hydrophilic polymer containing a hydroxyethylene unit is preferable. In addition, as the hydrophilic or alcoholic binder, for example, a polymer such as polyvinyl butyral can be suitably used.

The hydrophilic polymer which is one of the preferred embodiments of the binder polymer will be described in detail.
The hydrophilic polymer refers to a water-soluble or water-swellable polymer. Here, in the present invention, “water solubility” means that 5% by mass or more is dissolved in water at 25 ° C., and “water swellability” is 5% by mass in water at 25 ° C. When added in such a manner, it absorbs water and expands, and when it is visually observed, it does not dissolve, but it indicates that there is no clear solid (powder) precipitate.

  As the hydrophilic polymer, a single polymer may be used, or a plurality of types of polymers may be used.

  Examples of the hydrophilic polymer include hydrophilic polymers containing hydroxyethylene units, polysaccharides having hydrophilic functional groups such as cellulose, and salt structures and amino acids neutralized with acidic functional groups such as sodium polyacrylate. Examples thereof include an acrylic resin containing a salt structure or an onium structure in which the group is neutralized, a polyamide resin or a polyester resin into which a hydrophilic group such as polyethylene oxide is introduced, gelatin, and the like.

  Hydrophilic polymers include hydrophilic polymers containing hydroxyethylene, polar groups such as amino groups or carboxylic acid groups / sulfonic acid groups / sulfuric acid groups, and salt structures in which these are neutralized in that they exhibit good hydrophilicity. Cellulose, amino group or polar group-containing acrylic resin such as carboxylic acid group / sulfonic acid group / sulfuric acid group and salt structure in which these are neutralized, and polyamide resin are preferred. More preferably, hydrophilic polymers containing hydroxyethylene, polar groups-containing acrylic resins such as amino groups or carboxylic acid groups / sulfonic acid groups / sulfuric acid groups and salt structures in which these are neutralized, and polyamide resins are more preferable. Polyvinyl alcohols and polyamide resins.

Particularly preferred as the hydrophilic polymer is a polymer selected from polyvinyl alcohol (PVA) and derivatives thereof from the viewpoint of film property and resistance to UV ink.
The PVA and the PVA derivative will be specifically described as preferable examples of the vinyl polymer described later.
In the present invention, PVA and derivatives thereof contain 0.1 to 100 mol% of hydroxyethylene units, preferably 1 to 98 mol%, more preferably 5 to 95 mol%. A copolymer or a polymer thereof and modified products thereof.

  As the hydrophilic polymer, in particular, one or more selected from PVA and derivatives thereof and a hydrophilic polymer not containing a hydroxyethylene unit (hereinafter also referred to as “non-PVA derivative” as appropriate) may be used in combination. Good.

Examples of the method for synthesizing the hydrophilic polyamide include the following.
A polyamide having a polyethylene glycol unit is obtained by reacting ε-caprolactam and / or adipic acid with polyethylene glycol modified with both terminal amines, and a hydrophilic polyamide having a piperazine skeleton is obtained by reacting with piperazine. Moreover, the hydrophilic polyamide by which the crosslinkable functional group was introduce | transduced into the polymer is obtained by making the amide group of hydrophilic polyamide and the epoxy group of glycidyl methacrylate react. These non-PVA derivatives may be used alone or in combination of two or more.

Further, the non-PVA derivative means a substance having a polarity close to the degree of compatibility with PVA and its derivatives.
Specifically, as the non-PVA derivative, for example, hydrophilicity in which a hydrophilic group such as polyethylene glycol or piperazine is introduced into water-insoluble polyamide obtained by polymerization of only adipic acid, 1,6-hexanediamine, and ε-caprolactam. Include polyamides. A hydrophilic polyamide is suitable for use as a non-PVA derivative because it exhibits compatibility with the PVA derivative by the action of the hydrophilic group. In other words, such a hydrophilic polyamide has good compatibility with PVA and its derivatives, and easily enters between the molecules of PVA and its derivatives. Will be flexible.

(Hydrophobic polymer)
As the binder polymer in the present invention, a relatively hydrophobic binder polymer may be used.
In order to adjust properties such as film hardness and flexibility at the time of film formation, compatibility with other components such as a polymerizable compound and an initiator, the relatively hydrophobic binder polymer is shown below. A polymer containing such a monomer as a polymerization or copolymerization component can also be used.
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, β-hydroxy-β ′-(meth) (Meth) acrylate having a hydroxyl group such as acryloyloxyethyl phthalate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) Alkyl (meth) acrylates such as acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate, chloroethyl (meth) Alkyl halides (meth) acrylates such as acrylate and chloropropyl (meth) acrylate, alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and butoxyethyl (meth) acrylate, phenoxyethyl acrylate Alkoxyalkylene glycols (meth) such as phenoxyalkyl (meth) acrylates such as nonylphenoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate Acrylate, (meth) acrylamide, diacetone (meth) acrylamide, N, N′-methylenebis (meth) acryl (Meth) acrylamides such as amides, 2,2-dimethylaminoethyl (meth) acrylate, 2,2-diethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethyl Compounds having only one ethylenically unsaturated bond such as aminopropyl (meth) acrylamide, di (meth) acrylate of polyethylene glycol such as diethylene glycol di (meth) acrylate, such as dipropylene glycol di (meth) acrylate Polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol tri (meth) acrylate Such as polyvalent (meth) acrylates and glycidyl (meth) acrylates obtained by addition reaction of compounds with ethylenically unsaturated bonds and active hydrogen, such as unsaturated carboxylic acids and unsaturated alcohols, with ethylene glycol diglycidyl ether Polyhydric (meth) acrylamides such as polyvalent (meth) acrylates and methylenebis (meth) acrylamides obtained by the addition reaction of unsaturated epoxy compounds with compounds having active hydrogen such as carboxylic acids and amines, and many compounds such as divinylbenzene. And compounds having two or more ethylenically unsaturated bonds, such as a valent vinyl compound. In this invention, these can be used individually or in combination of 2 or more types.

  From the viewpoint of film property, the monomer of the polymerization component is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytrile. Alkoxyalkylene glycol (meth) acrylates such as ethylene glycol (meth) acrylate and methoxydipropylene glycol (meth) acrylate, (meth) acrylamide, diacetone (meth) acrylamide, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, N -Acryloylmorpholine is preferred. Among these, acrylates are particularly preferable from the viewpoint of ensuring flexibility of the obtained polymer.

In addition, the following polymers can also be used as the binder polymer.
That is, a polymer containing at least one of an olefin and a carbon-carbon triple bond in the main chain is exemplified. For example, SB (polystyrene-polybutadiene), SBS (polystyrene-polybutadiene-polystyrene), SIS (polystyrene-polyisoprene-polystyrene). , SEBS (polystyrene-polyethylene / polybutylene-polystyrene) and the like.

(Polymer having carbon-carbon unsaturated bond)
As the binder polymer, a polymer having a carbon-carbon unsaturated bond in the molecule can be suitably used. The carbon-carbon unsaturated bond may be present in either the main chain or the side chain of the polymer, and may be present in both. Hereinafter, the carbon-carbon unsaturated bond may be simply referred to as “unsaturated bond”, and the carbon-carbon unsaturated bond remaining at the end of the main chain or side chain may be referred to as “polymerizable group”. .
When having a carbon-carbon unsaturated bond in the main chain of the polymer, it may be present at one end, both ends, or in the main chain of the polymer main chain. Moreover, when it has a carbon-carbon unsaturated bond in the side chain of a polymer, this unsaturated bond may be directly couple | bonded with the principal chain structure, and may be couple | bonded through the suitable coupling group.

  Examples of the polymer containing a carbon-carbon unsaturated bond in the main chain include SB (polystyrene-polybutadiene), SBS (polystyrene-polybutadiene-polystyrene), SIS (polystyrene-polyisoprene-polystyrene), SEBS (polystyrene-polyethylene / polybutylene). -Polystyrene) and the like.

  When a polymer having a highly reactive polymerizable unsaturated group such as a methacryloyl group is used as a polymer having a carbon-carbon unsaturated bond in the side chain, a film having extremely high mechanical strength can be produced. In particular, in polyurethane-based and polyester-based thermoplastic elastomers, it is possible to introduce a highly reactive polymerizable unsaturated group into the molecule relatively easily.

  When an unsaturated bond or a polymerizable group is introduced into the binder polymer, a structural unit having a polymerizable group precursor formed by bonding a protective group to the polymerizable group is copolymerized with the polymer to remove the protective group. Reactive group such as hydroxyl group, amino group, epoxy group, carboxyl group, acid anhydride group, ketone group, hydrazine residue, isocyanate group, isothiocyanate group, cyclic carbonate group, ester group And then reacting a binder having a plurality of groups capable of binding to the reactive group (for example, polyisocyanate in the case of a hydroxyl group or an amino group) to adjust the molecular weight and Is converted to a bonding group, and then reacted with an organic compound having a polymerizable unsaturated group and a group that reacts with the terminal bonding group, and a polymerizable group is obtained by a polymer reaction. A method of introducing, it is possible to take any known method. According to these methods, the amount of unsaturated bond and polymerizable group introduced into the polymer compound can be controlled.

Such a polymer having an unsaturated bond is also preferably used in combination with a polymer having no unsaturated bond. That is, a polymer obtained by adding hydrogen to the olefin part of the polymer having a carbon-carbon unsaturated bond, or a monomer hydrogenated to the olefin part, for example, a monomer hydrogenated to butadiene, isoprene, or the like, is used as a raw material. The polymer obtained by forming can be used together because it is excellent in compatibility, and the amount of unsaturated bonds of the binder polymer can be adjusted.
When these are used in combination, the polymer having no unsaturated bond is generally 1 part by mass to 90 parts by mass, preferably 5 parts by mass to 80 parts by mass with respect to 100 parts by mass of the polymer having an unsaturated bond. Can be used in proportions.
As will be described later, in the case where the curing property is not required for the binder polymer, such as when other polymerizable compounds are used in combination, an unsaturated bond is not necessarily required for the binder polymer, and various polymers having no unsaturated bond. Alone can also be used as the binder polymer. Preferred examples of the polymer having no unsaturated bond in such a case include polyester, polyamide, polystyrene, acrylic resin, acetal resin, and polycarbonate.

  The number average molecular weight of the binder polymer having or not having an unsaturated bond that can be used in the present invention is preferably in the range of 10,000 to 1,000,000. A more preferable range is from 50,000 to 500,000. When the number average molecular weight is in the range of 10,000 to 1,000,000, the mechanical strength of the formed film can be ensured. The number average molecular weight is measured using gel permeation chromatography (GPC), and evaluated with respect to a polystyrene sample having a known molecular weight.

As the binder polymer in the present invention, among various binder polymers as described above, it is preferable to use a polymer selected from the group consisting of vinyl polymers, polyamides, polyurethanes, and polyureas from the viewpoint of improving engraving sensitivity. .
Hereinafter, these preferable binder polymers will be described.

(Vinyl polymer)
The vinyl polymer according to the present invention includes acrylic ester, methacrylic ester, vinyl ester, acrylamide, methacrylamide, olefin, styrene, crotonic ester, itaconic acid diester, as shown below. Polymers or copolymers obtained from vinyl monomers such as maleic acid diesters and fumaric acid diesters are preferred, but the present invention is not limited to these.

  Acrylic acid esters: for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, Octyl acrylate, tert-octyl acrylate, 2-chloroethyl acrylate, 2-bromoethyl acrylate, 4-chlorobutyl acrylate, cyanoethyl acrylate, 2-acetoxyethyl acrylate, dimethylaminoethyl acrylate, benzyl acrylate, methoxybenzyl acrylate, 2-chloro Cyclohexyl acrylate, cyclohexyl acrylate, full-free Acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, 5-hydroxypentyl acrylate, 2,2-dimethyl-3-hydroxypropyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, 2-ethoxyethyl acrylate, 2-iso- Propoxyethyl acrylate, 2-butoxyethyl acrylate, 2- (2-methoxyethoxy) ethyl acrylate, 2- (2-butoxyethoxy) ethyl acrylate, ω-methoxypolyethylene glycol acrylate (added mole number n = 9), 1-bromo 2-methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate

  Methacrylic acid esters: for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate Chlorobenzyl methacrylate, octyl methacrylate, sulfopropyl methacrylate, N-ethyl-N-phenylaminoethyl methacrylate, 2- (3-phenylpropyloxy) ethyl methacrylate, dimethylaminophenoxyethyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, Phenyl methacrylate , Cresyl methacrylate, naphthyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, triethylene glycol monomethacrylate, dipropylene glycol monomethacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, 2-acetoxyethyl methacrylate 2-acetoacetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-iso-propoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2- (2-methoxyethoxy) ethyl methacrylate, 2- (2-ethoxyethoxy) ethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate, ω-methoxypolyethylene glycol methacrylate ( Number of added moles n = 6)

  Vinyl esters: for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxy acetate, vinyl phenyl acetate, vinyl benzoate, vinyl salicylate

  Acrylamides: For example, acrylamide, methyl acrylamide, ethyl acrylamide, propyl acrylamide, butyl acrylamide, tert-butyl acrylamide, cyclohexyl acrylamide, benzyl acrylamide, hydroxymethyl acrylamide, methoxyethyl acrylamide, dimethylaminoethyl acrylamide, phenyl acrylamide, dimethyl acrylamide, diethyl Acrylamide, β-cyanoethylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, diacetoneacrylamide

  Methacrylamide: for example, methacrylamide, methyl methacrylamide, ethyl methacrylamide, propyl methacrylamide, butyl methacrylamide, tert-butyl methacrylamide, cyclohexyl methacrylamide, benzyl methacrylamide, hydroxymethyl methacrylamide, methoxyethyl methacrylamide, dimethyl Aminoethylmethacrylamide, phenylmethacrylamide, dimethylmethacrylamide, diethylmethacrylamide, β-cyanoethylmethacrylamide, N- (2-acetoacetoxyethyl) methacrylamide

Olefins: for example, dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene styrenes: for example, styrene, methylstyrene, dimethyl Styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester

Crotonic acid esters: for example, butyl crotonic acid, hexyl crotonic acid, itaconic acid diesters: for example, dimethyl itaconate, diethyl itaconate, dibutyl itaconate Maleic acid diesters: for example, diethyl maleate, dimethyl maleate, dibutyl maleate Fumarate diesters: for example, diethyl fumarate, dimethyl fumarate, dibutyl fumarate and the like.

Moreover, the following are mentioned as an example of the other monomer used when obtaining a vinyl-type polymer.
Allyl compounds: for example, allyl acetate, allyl caproate, allyl laurate, allyl benzoate;
Vinyl ethers: for example, methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether;
Vinyl ketones: For example, methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone;
Vinyl heterocyclic ring compounds: for example, vinylpyridine, N-vinylimidazole, N-vinyloxazolidone, N-vinyltriazole, N-vinylpyrrolidone;
Glycidyl esters: for example, glycidyl acrylate, glycidyl methacrylate;
Unsaturated nitriles: For example, acrylonitrile, methacrylonitrile;

  The vinyl polymer used in the present invention may be a homopolymer of the above-mentioned monomer, or may be a copolymer obtained from two or more kinds of monomers as required.

The binder polymer in the present invention is preferably a vinyl polymer that is soluble in water and / or ethanol among vinyl polymers.
Here, in the present invention, “a polymer soluble in water and / or ethanol” means that, when the solubility is observed as follows, there is no polymer precipitate, and the solution (dispersion) is It means something that is transparent and uniform.
That is, 0.1 g of a powder or pellet binder polymer and 2 mL of water or 2 mL of ethanol are mixed, capped, and allowed to stand at room temperature for 24 hours, and then the solubility is visually observed.

  As the vinyl polymer soluble in water and / or ethanol, polyvinyl alcohol (PVA) derivatives are preferred. Here, the PVA derivative in the present invention contains hydroxyethylene units in an amount of 0.1 mol% to 100 mol%, preferably 1 mol% to 98 mol%, more preferably 5 mol% to 95 mol%. It means a copolymer or a polymer, and modified products thereof. Therefore, polyvinyl alcohol itself is also included. The monomer for forming the copolymer can be appropriately selected from known copolymerizable monomers. Examples of the modified body include those described below.

  Examples of modified PVA derivatives include polymers in which at least some of the hydroxyl groups of the hydroxyethylene units are modified to carboxyl groups, polymers in which some of the hydroxyl groups are modified to (meth) acryloyl groups, and at least some of the hydroxyl groups are amino. Examples thereof include a polymer modified with a group, and a polymer in which ethylene glycol, propylene glycol and a multimer thereof are introduced into at least a part of the hydroxyl group.

A polymer obtained by modifying at least a part of the hydroxyl group of a hydroxyethylene unit to a carboxyl group is esterified with polyvinyl alcohol or partially saponified polyvinyl alcohol and a polyfunctional carboxylic acid such as succinic acid, maleic acid or adipic acid. Can be obtained.
The amount of the carboxyl group introduced is 0.01 mol to 1 mol per mol of the hydroxyl group. 00 mol is preferable, and 0.05 mol to 0.80 mol is more preferable.

A polymer obtained by modifying at least a part of hydroxyl groups of a hydroxyethylene unit to a (meth) acryloyl group can be obtained by adding glycidyl (meth) acrylate to the carboxyl group-modified polymer, or by adding polyvinyl alcohol or partially saponified polyvinyl alcohol ( It can be obtained by esterification with (meth) acrylic acid.
The amount of (meth) acryloyl group introduced is preferably 0.01 mol to 1.00 mol, and more preferably 0.03 mol to 0.50 mol, with respect to 1 mol of the hydroxyl group.
In addition, the description with a (meth) acryloyl group is a general term for an acryloyl group and / or a methacryloyl group. The notation (meth) acrylate is a general term for acrylate and / or methacrylate. The same applies to (meth) acrylic acid and the like.

A polymer in which at least a part of the hydroxyl groups of the hydroxyethylene unit is modified with an amino group is obtained by esterification with polyvinyl alcohol or partially saponified polyvinyl alcohol and a carboxylic acid containing an amino group such as carbamic acid. be able to.
The amount of amino group introduced is preferably 0.01 mol to 1.00 mol, more preferably 0.05 mol to 0.70 mol, per 1 mol of the hydroxyl group.

Polymers in which ethylene glycol, propylene glycol, or a multimer thereof is introduced into at least a part of the hydroxyl groups of the hydroxyethylene unit are obtained by heating polyvinyl alcohol or partially saponified polyvinyl alcohol and glycols under a sulfuric acid catalyst as a by-product. It can be obtained by removing some water out of the reaction system.
The total amount of ethylene glycol, propylene glycol, and their multimers introduced is preferably 0.01 mol to 0.90 mol, more preferably 0.03 mol to 0.50 mol, per mol of the hydroxyl group.

  Among these modified products, a polymer obtained by modifying at least a part of the hydroxyl group of the hydroxyethylene unit to a (meth) acryloyl group is preferably used. That is, by directly introducing an unreacted crosslinkable functional group into such a hydrophilic polymer, for example, the strength of the cured film can be obtained without using a large amount of a polymerizable compound having an ethylenically unsaturated bond as described later. This is because it is possible to enhance the flexibility and strength of the cured film.

  Moreover, polyvinyl acetal can also be used effectively as the vinyl polymer of the present invention. As the polyvinyl acetal, those obtained by treating polyvinyl alcohol with aldehydes can be used. The aldehydes used in the acetal treatment are specifically described below, but are not limited.

  Aldehydes used for acetal treatment include aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, t-butyraldehyde, amyl aldehyde, hexyl aldehyde and 2-ethylhexyl aldehyde, and fats such as cyclohexyl aldehyde and furfural. Examples include aromatic aldehydes such as cyclic aldehydes, benzaldehyde, alkyl-substituted benzaldehyde, halogen-substituted benzaldehyde, and phenyl-substituted alkyl aldehyde. Among these, acetaldehyde and butyraldehyde are preferably used because they are easy to handle. These aldehydes may be used alone or in combination of two or more.

(polyamide)
Polyamide can be obtained by polycondensation of a diamine compound and a dicarboxylic acid compound, polycondensation of an aminocarboxylic acid compound, ring-opening polymerization of lactams, and the like.
Examples of diamine compounds, dicarboxylic acid compounds, aminocarboxylic acid compounds, and lactams used when synthesizing the polyamide in the present invention will be given below, but the present invention is not limited to these.

Examples of diamine compounds include ethylenediamine, 1,3-propanediamine, 1,2-propanediamine, hexamethylenediamine, octamethylenediamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, piperazine, 2, Examples include 5-dimethylpiperazine, 4,4′-diaminophenyl ether, 3,3′-diaminodiphenyl sulfone, and xylylenediamine.
Examples of dicarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, glutaric acid, dimethylmalonic acid, adipic acid, pimelic acid, α, α-dimethylsuccinic acid, acetone dicarboxylic acid, sebacic acid, 1,9-nonane. Dicarboxylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, 2-butyl terephthalic acid, tetrachloroterephthalic acid, acetylenedicarboxylic acid, poly (ethylene terephthalate) dicarboxylic acid, 1,2 -Cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, ω-poly (ethyleneoxy) dicarboxylic acid, p-xylylene dicarboxylic acid, and the like.
These dicarboxylic acid compounds may be used in the form of alkyl esters of carboxylic acids (for example, dimethyl esters) or acid chlorides of dicarboxylic acids, or acid anhydrides such as maleic anhydride, succinic anhydride, and phthalic anhydride. It may be used in the form of a thing.

Examples of aminocarboxylic acids include glycine, alanine, phenylalanine, ω-aminohexanoic acid, ω-aminodecanoic acid, ω-aminoundecanoic acid, anthranilic acid and the like.
Examples of monomers (lactams) used for ring-opening polymerization include ω-caprolactam, azetidinone, and pyrrolidone.

(Polyurethane)
Polyurethane is basically synthesized by a polyaddition reaction using a diol compound and a diisocyanate compound as raw materials.
Hereinafter, although the example of the diol compound and diisocyanate compound used when synthesize | combining the polyurethane in this invention is given, this invention is not limited to these.

  Specific examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, and 2,2-dimethyl-1,3-propane. Diol, 1,4-pentanediol, 2,4-pentanediol, 3,3-dimethyl-1,2-butanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,6-hexanediol 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,2-diethyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2-methyl-2 -Propyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-octa Diol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol (average molecular weight = 200, 300, 400 600, 1000, 1500, 4000), polypropylene glycol (average molecular weight = 200, 400, 1000), polyester polyol, 4,4′-dihydroxy-diphenyl-2,2-propane, 4,4-dihydroxyphenylsulfone, 2, , 2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,5,6-trimethoxy-3,4-dihydroxyhexanoic acid, 2,3-dihydroxy-4,5-dimethoxy pen Phosphate, 2,4-di (2-hydroxyethyl) ethyloxycarbonyl benzenesulfonic acid, and their salts.

  Preferred specific examples of the diisocyanate compound include ethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-toluene diisocyanate, 1,3-xylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene. Examples include diisocyanate, p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 3,3′-dimethylbiphenylene diisocyanate, dicyclohexylmethane diisocyanate, and methylenebis (4-cyclohexylisocyanate).

(Polyurea)
Polyurea can be basically obtained by polyaddition of a diamine compound and a diisocyanate compound or a deammonification reaction of a diamine compound and urea.
Hereinafter, examples of the diamine compound and the diisocyanate compound used when synthesizing the polyurea in the present invention will be given, but the present invention is not limited to these.

Examples of the diamine compound include compounds selected from the same group as the diamines described in the polyamide.
Moreover, as a diisocyanate compound, the compound chosen from the same group as diisocyanate demonstrated in the said polyurethane can be mentioned.

  In the present invention, the binder polymer is particularly preferably a vinyl polymer from the viewpoint of engraving sensitivity, and more preferably a vinyl polymer soluble in water and / or ethanol.

  The weight average molecular weight (polystyrene conversion by GPC measurement) of the binder polymer in the present invention is preferably 50,000 to 500,000 for both the binder polymer selected from the aforementioned group a and other binder polymers. If the weight average molecular weight is 50,000 or more, the form retainability as a single resin is excellent, and if it is 500,000 or less, it is easy to dissolve in a solvent such as water, which is convenient for preparing a resin composition for laser engraving. is there. The weight average molecular weight of the binder polymer is more preferably 10,000 to 400,000, particularly preferably 15,000 to 300,000.

The total content of the binder polymer is preferably 5% by mass to 80% by mass, preferably 15% by mass to 75% by mass, and 20% by mass to 65% by mass with respect to the total mass of the solid content of the resin composition for laser engraving. More preferred.
For example, when the resin composition for laser engraving of the present invention is applied to the relief forming layer of a relief printing plate precursor, the resulting relief printing plate can be used as a printing plate by setting the binder polymer content to 15% by mass or more. Printing durability sufficient for use is obtained, and when it is 75% by mass or less, other components are not deficient, and it is sufficient to be used as a printing plate even when a relief printing plate is used as a flexographic printing plate. Flexibility can be obtained.

  In the present invention, when (A) a sulfur-containing polyfunctional monomer and a poly (hydroxycarboxylic acid) ester such as polylactic acid are used in combination, engraving sensitivity can be further improved. This is presumably because, as described above, the active species generated during the depolymerization of polylactic acid accelerates the decomposition of the monomer by nucleophilic attack on the sulfur-containing polyfunctional monomer (A).

  The resin composition for laser engraving of the present invention may contain optional components such as a photothermal conversion agent, a polymerization initiator, and a plasticizer together with the above-described (A) sulfur-containing polyfunctional monomer and (B) binder polymer as essential components. preferable. Hereinafter, each of these components will be described in detail.

<(C) Photothermal conversion agent>
The resin composition for laser engraving of the present invention preferably contains (C) a photothermal conversion agent. It is considered that the photothermal conversion agent promotes thermal decomposition of the cured product of the resin composition for laser engraving of the present invention by absorbing laser light and generating heat. Therefore, it is preferable to select a photothermal conversion agent that absorbs light having a laser wavelength used for engraving.

When a laser (YAG laser, semiconductor laser, fiber laser, surface emitting laser, etc.) emitting an infrared ray having a wavelength of 700 nm to 1300 nm is used as a light source for laser engraving, the relief forming layer in the present invention is a light having a wavelength of 700 nm to 1300 nm. It is preferable to contain a photothermal conversion agent capable of absorbing water.
Various dyes or pigments are used as the photothermal conversion agent in the present invention.

  Among the photothermal conversion agents, as the dye, commercially available dyes and known ones described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, diimmonium compounds, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes And the like.

Examples of the dye preferably used in the present invention include the dyes described in paragraphs [0124] to [0137] of JP-A-2008-63554.
One suitable photothermal conversion agent in the present invention is at least one compound selected from cyanine compounds and phthalocyanine compounds from the viewpoint of high engraving sensitivity. Further, when the photothermal conversion agent is used in a combination (condition) in which the thermal decomposition temperature of the hydrophilic polymer suitable as the binder polymer is equal to or higher than the thermal decomposition temperature, the engraving sensitivity tends to be further increased, which is preferable.

Of the photothermal conversion agents used in the present invention, the dye is preferably a dye having an absorption maximum at a wavelength of 700 nm to 1300 nm.
Dyes that can be preferably used in the present invention include cyanine dyes such as heptamethine cyanine dyes, oxonol dyes such as pentamethine oxonol dyes, indolium dyes, benzindolinium dyes, benzothiazolium dyes, quinolinium Among the phthalide compounds and the like reacted with a system dye and a developer, those having a maximum absorption wavelength at 700 nm to 1300 nm can be mentioned. The light absorption characteristics vary greatly depending on the type of substituent and position in the molecule, the number of conjugated bonds, the type of counterion, the surrounding environment in which the dye molecule is present, and the like.

  Further, commercially available laser dyes, supersaturated absorbing dyes, and near infrared absorbing dyes can also be used. For example, as a laser dye, trade marks “ADS740PP”, “ADS745HT”, “ADS760MP”, “ADS740WS”, “ADS765WS”, “ADS745NH”, “ADS790NH”, “ADS800NH” of American Diese Source (Canada), Trademarks “NK-3555”, “NK-3509”, and “NK-3519” manufactured by Hayashibara Biochemical Laboratories, Inc. can be mentioned. In addition, as a near-infrared absorbing pigment, trade names “ADS775MI”, “ADS775MP”, “ADS775HI”, “ADS775PI”, “ADS775PP”, “ADS780MT”, “ADS780BP”, “ADS793EI”, trade names “ADS775MI”, “ADS775MP”, “ADS775HI” , “ADS798MI”, “ADS798MP”, “ADS800AT”, “ADS805PI”, “ADS805PP”, “ADS805PA”, “ADS805PF”, “ADS812MI”, “ADS815EI”, “ADS818HI”, “ADS818HT”, “ADS8” ADS830AT, ADS838MT, ADS840MT, ADS845BI, ADS905AM, ADS956BI, ADS1040T, "ADS1040P", "ADS1045P", "ADS1050P", "ADS1060A", "ADS1065A", "ADS1065P", "ADS1100T", "ADS1120F", "ADS1120P", "ADS780WS", "ADS785WS", "ADS790WS", "ADS790WS", "ADS790WS" , “ADS820WS”, “ADS830WS”, “ADS850WS”, “ADS780HO”, “ADS810CO”, “ADS820HO”, “ADS821NH”, “ADS840NH”, “ADS880MC”, “ADS890MC”, “Yamamoto Co., Ltd.” , Trademarks “YKR-2200”, “YKR-2081”, “YKR-2900”, “YKR-2100”, “YKR-3071”, Arimoto Made by Manabu Industry Co., Ltd., trademark "SDO-1000B", Hayashibara Biochemical Laboratories Inc., trademark "NK-3508", mention may be made of the "NKX-114". However, it is not limited only to these.

  Among the photothermal conversion agents used in the present invention, commercially available pigments and color index (CI) manuals, “latest pigment manuals” (edited by the Japan Pigment Technical Association, published in 1977), “latest pigment application” The pigments described in “Technology” (CMC Publishing, 1986) and “Printing Ink Technology” CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

  As long as the dispersibility in the composition is stable, carbon black can be used regardless of the classification according to ASTM or the use (for example, for color, for rubber, for dry battery, etc.). Carbon black includes, for example, furnace black, thermal black, channel black, lamp black, acetylene black and the like. In order to facilitate dispersion, black colorants such as carbon black can be used as color chips or color pastes previously dispersed in nitrocellulose or a binder, if necessary. Such chips and pastes can be easily obtained as commercial products.

  In the present invention, it is also possible to use carbon black having a relatively low specific surface area and relatively low DBP absorption and even finer carbon black having a large specific surface area. Examples of suitable carbon blacks include Printex® U, Printex® A, or Specialschwarz® 4 (from Degussa).

The carbon black that can be applied to the present invention has a specific surface area of at least 150 m ² / g and a DBP number of at least from the viewpoint of improving engraving sensitivity by efficiently transferring heat generated by photothermal conversion to surrounding polymers. Conductive carbon black, which is 150 ml / 100 g, is preferred.

This specific surface area is preferably at least 250, particularly preferably at least 500 m ² / g. The DBP number is preferably at least 200, particularly preferably at least 250 ml / 100 g. The carbon black described above may be acidic or basic carbon black. The carbon black is preferably basic carbon black. Of course, mixtures of different binders can also be used.

Suitable conductive carbon blacks with specific surface areas up to about 1500 m ² / g and DBP numbers up to about 550 ml / 100 g are for example Ketjenblack® EC300J, Ketjenblack® EC600J (from Akzo), It is commercially available under the names Princex® XE (from Degussa) or Black Pearls® 2000 (from Cabot), Ketjen Black (manufactured by Lion Corporation).

  The content of the photothermal conversion agent in the resin composition for laser engraving varies greatly depending on the molecular extinction coefficient inherent to the molecule, but is 0.01% by mass to 20% by mass of the total solid content of the resin composition. Is preferable, more preferably 0.05% by mass to 10% by mass, and particularly preferably 0.1% by mass to 5% by mass.

<(D) Polymerization initiator>
The resin composition for laser engraving of the present invention preferably contains (D) a polymerization initiator.
As the polymerization initiator, those known to those skilled in the art can be used without limitation. Specifically, for example, Bruce M. Monroe et al., Chemical Revue, 93, 435 (1993) and RSD Davidson, Journal of Photochemistry and biology A: Chemistry, 73.81 (1993); JPFaussier, “Photoinitiated Polymerization-Theory and Applications ": Rapra Review vol. 9, Report, Rapra Technology (1998); M. Tsunooka et al., Prog. Polym. Sci., 21, 1 (1996). FDSaeva, Topics in Current Chemistry, 156, 59 (1990); GGMaslak, Topics in Current Chemistry, 168, 1 (1993); HBShuster et al, JACS, 112,6329 (1990); IDFEaton et al, JACS, 102 , 3298 (1980) and the like, a group of compounds that cause oxidative or reductive bond cleavage is also known.

  Hereinafter, a specific example of a preferable polymerization initiator will be described in detail with respect to a radical polymerization initiator which is a compound that generates radicals by light and / or heat energy and initiates and accelerates a polymerization reaction with the polymerizable compound. Are not limited by these statements.

  In the present invention, preferred radical polymerization initiators include (a) aromatic ketones, (b) onium salt compounds, (c) organic peroxides, (d) thio compounds, (e) hexaarylbiimidazole compounds, (F) ketoxime ester compound, (g) borate compound, (h) azinium compound, (i) metallocene compound, (j) active ester compound, (k) compound having carbon halogen bond, (l) azo compound, etc. Is mentioned. Specific examples of the above (a) to (l) are given below, but the present invention is not limited to these.

In the present invention, from the viewpoint of engraving sensitivity and a good relief edge shape when applied to a relief forming layer of a relief printing plate precursor, (c) an organic peroxide and (l) an azo compound are more Preferably, (c) an organic peroxide is particularly preferable.
Normally, engraving sensitivity decreases when the hardness is increased to improve the edge shape of the relief. The edge shape can be improved without lowering. This is probably because the oxygen atom or nitrogen atom in the polymerization initiator forms an interaction with the sulfur atom of the (A) sulfur-containing polyfunctional monomer, and the degree of polymerization increases due to the presence of both components in close proximity. Therefore, it is expected that the edge shape is improved, and the low-temperature thermal decomposition characteristics of the (A) sulfur-containing polyfunctional monomer are expected to suppress a decrease in sensitivity due to an increase in the degree of polymerization.

(A) aromatic ketones, (b) onium salt compounds, (d) thio compounds, (e) hexaarylbiimidazole compounds, (f) ketoxime ester compounds, (g) borate compounds, (h) azinium compounds , (I) metallocene compounds, (j) active ester compounds, and (k) compounds having a carbon halogen bond are preferably the compounds listed in paragraphs [0074] to [0118] of JP-A-2008-63554. Can be used.
In addition, (c) the organic peroxide and (l) the azo compound are preferably the following compounds.

(C) Organic peroxide Preferred as a radical polymerization initiator that can be used in the present invention (c) Organic peroxide includes almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. Examples include methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tertiary butyl peroxy) -3,3. 5-trimethylcyclohexane, 1,1-bis (tertiary butyl peroxy) cyclohexane, 2,2-bis (tertiary butyl peroxy) butane, tertiary butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene Hydroperoxide, parameter hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, ditertiary butyl peroxide, tertiary butyl Cumyl peroxide, dicumyl peroxide, bis (tertiary butyl peroxyisopropyl) benzene, 2,5-dimethyl-2,5-di (tertiary butyl peroxy) hexane, 2,5-xanoyl peroxide, peroxy Succinic oxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, meta-toluoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxy Carbonate, dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tertiary butyl peroxyacetate, tertiary butyl peroxypivalate, tertiary butyl peroxyneodecanoate, tarsha Libutyl butyl peroxy octanoate, Tertiary butyl peroxy-3,5,5-trimethylhexanoate, Tertiary butyl peroxy laurate, Tertiary carbonate, 3,3'4,4'-Tetra- (tarsha Libutyl oxyperoxycarbonyl) benzophenone, 3,3′4,4′-tetra- (tertiary amyl peroxycarbonyl) benzophenone, 3,3′4,4′-tetra- (tertiary hexylperoxycarbonyl) benzophen Non, 3,3′4,4′-tetra- (tertiary octylperoxycarbonyl) benzophenone, 3,3′4,4′-tetra- (cumylperoxycarbonyl) benzophenone, 3,3′4,4 ′ -Tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (tertiarybutylperoxydihydrogen diphthalate), carbonyldi (tertiary hexylperoxydihydrogendiphthalate) and the like.

  Among them, 3,3′4,4′-tetra- (tertiary butyl peroxycarbonyl) benzophenone, 3,3′4,4′-tetra- (tertiary amyl peroxycarbonyl) benzophenone, 3,3′4 4'-tetra- (tertiary hexylperoxycarbonyl) benzophenone, 3,3'4,4'-tetra- (tertiary octylperoxycarbonyl) benzophenone, 3,3'4,4'-tetra- (cumylper) Peroxyesters such as oxycarbonyl) benzophenone, 3,3′4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, di-tertiary butyldiperoxyisophthalate are preferred.

(L) Azo-based compound Preferred as a radical polymerization initiator that can be used in the present invention (l) As the azo-based compound, 2,2′-azobisisobutyronitrile, 2,2′-azobispropionitrile, 1 , 1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′- Azobis (4-methoxy-2,4-dimethylvaleronitrile), 4,4′-azobis (4-cyanovaleric acid), dimethyl 2,2′-azobisisobutyrate, 2,2′-azobis (2-methylpropionamide) Oxime), 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2- Hydro Ethyl] propionamide}, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis (N-butyl-2-methylpropionamide), 2,2 '-Azobis (N-cyclohexyl-2-methylpropionamide), 2,2'-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2'-azobis (2,4,4- Trimethylpentane) and the like.

The polymerization initiator in the present invention may be used alone or in combination of two or more.
The polymerization initiator can be added in an amount of preferably 0.01 to 10% by mass, more preferably 0.1 to 3% by mass, based on the total solid content of the resin composition for laser engraving.

<Other additives>
The resin composition for laser engraving of the present invention preferably contains a plasticizer. The plasticizer has a function of softening a film formed of the resin composition for laser engraving, and needs to have good compatibility with the binder polymer.
As the plasticizer, for example, dioctyl phthalate, didodecyl phthalate or the like, polyethylene glycols, polypropylene glycol (monool type or diol type), polypropylene glycol (monool type or diol type) are preferably used.
In the resin composition for laser engraving of the present invention, it is more preferable to add nitrocellulose or a highly thermally conductive substance as an additive for improving engraving sensitivity. Since nitrocellulose is a self-reactive compound, it generates heat during laser engraving and assists in the thermal decomposition of a binder polymer such as a hydrophilic polymer. As a result, it is estimated that the engraving sensitivity is improved.
The high thermal conductive material is added for the purpose of assisting heat transfer, and examples of the thermal conductive material include inorganic compounds such as metal particles and organic compounds such as conductive polymers. As the metal particles, the conductive polymer is preferably a gold fine particle, a silver fine particle, or a copper fine particle having a particle size of micrometer order to several nanometer order. It is done.
Moreover, the sensitivity at the time of photocuring the resin composition for laser engraving can be further improved by using a co-sensitizer.
Furthermore, it is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the polymerizable compound during the production or storage of the composition.
A colorant such as a dye or pigment may be added for the purpose of coloring the resin composition for laser engraving. Thereby, properties such as the visibility of the image portion and the suitability of the image density measuring device can be improved.
Furthermore, in order to improve the physical properties of the cured film of the resin composition for laser engraving, a known additive such as a filler may be added.

[Image forming materials]
The image forming material of the present invention has an image forming layer made of the resin composition for laser engraving of the present invention on a support.
The image forming material of the present invention is not particularly limited as long as it can form an image on the image forming layer by laser engraving, and includes a relief printing plate precursor for laser engraving described later, a three-dimensional structure, a seal. It can be applied to ablation mask layers, intaglio printing plates and the like.

[Relief printing plate precursor for laser engraving]
The relief printing plate precursor for laser engraving of the present invention has a relief forming layer comprising the resin composition for laser engraving of the present invention. The relief forming layer is preferably provided on the support.
In the present invention, the “relief printing plate precursor for laser engraving” refers to a state in which a crosslinkable relief forming layer made of a resin composition for laser engraving is cured by light or heat. A “relief printing plate” is produced by laser engraving the printing plate precursor.

  If necessary, the relief printing plate precursor for laser engraving may further have an adhesive layer between the support and the relief forming layer, and a slip coat layer and a protective film on the relief forming layer.

<Relief forming layer>
The relief forming layer is a layer made of the resin composition for laser engraving of the present invention, and is preferably a layer that is cured by at least one of light and heat, that is, a layer having crosslinkability.
The production mode of the relief printing plate using the relief printing plate precursor of the present invention is preferably a mode in which the relief printing plate is produced by forming a relief layer by crosslinking the relief forming layer and then laser engraving. By crosslinking the relief forming layer, wear of the relief layer during printing can be prevented, and a relief printing plate having a relief layer having a sharp shape after laser engraving can be obtained.

  In addition, a relief forming layer can be formed by using the coating liquid composition for relief forming layers, and shape | molding this to a sheet form or a sleeve form.

<Support>
The support that can be used for the relief printing plate precursor for laser engraving will be described.
The material used for the support for the relief printing plate precursor for laser engraving is not particularly limited, but materials having high dimensional stability are preferably used. For example, metals such as steel, stainless steel and aluminum, polyester (for example, PET, PBT, PAN ) And plastic resins such as polyvinyl chloride, synthetic rubber such as styrene-butadiene rubber, and plastic resins reinforced with glass fibers (such as epoxy resins and phenol resins). As the support, a PET (polyethylene terephthalate) film or a steel substrate is preferably used. The form of the support is determined depending on whether the relief forming layer is a sheet or a sleeve.

<Adhesive layer>
An adhesive layer may be provided between the relief forming layer and the support for the purpose of enhancing the adhesive force between the two layers.

  The material that can be used for the adhesive layer may be any material that strengthens the adhesive force after the relief forming layer is crosslinked, and preferably has a strong adhesive force before the relief forming layer is crosslinked. Here, the adhesive force means both the adhesive force between the support / adhesive layer and the adhesive layer / relief forming layer.

  When the adhesive layer and the relief forming layer are peeled from the laminate comprising the support / adhesive layer / relief forming layer at a rate of 400 mm / min, the peel force per 1 cm width of the sample is 1 It is preferably 0.0 N / cm or more or non-peeling, and more preferably 3.0 N / cm or more or non-peeling.

  The adhesive force of the adhesive layer / relief forming layer is such that when the adhesive layer is peeled from the adhesive layer / relief forming layer at a rate of 400 mm / min, the peel force per 1 cm width of the sample is 1.0 N / cm or more or cannot be peeled off. It is preferable that it is 3.0 N / cm or more, or more preferably non-peelable.

  Examples of materials (adhesives) that can be used for the adhesive layer include: Those described in the edition of Skeist, “Handbook of Adhesives”, the second edition (1977) can be used.

<Protective film, slip coat layer>
The relief forming layer becomes a portion (relief layer) where the relief is formed after laser engraving, and the surface of the relief layer functions as an ink depositing portion. Since the relief forming layer after cross-linking is reinforced by cross-linking, the surface of the relief forming layer hardly causes scratches or dents that affect printing. However, the relief forming layer before cross-linking is often insufficient in strength, and the surface is likely to have scratches and dents. From this point of view, a protective film may be provided on the surface of the relief forming layer for the purpose of preventing scratches or dents on the surface of the relief forming layer.

  If the protective film is too thin, the effect of preventing scratches and dents cannot be obtained. If the protective film is too thick, handling becomes inconvenient and the cost increases. Therefore, the thickness of the protective film is preferably 25 μm to 500 μm, and more preferably 50 μm to 200 μm.

  As the protective film, a known material as a protective film for a printing plate, for example, a polyester film such as PET (polyethylene terephthalate), or a polyolefin film such as PE (polyethylene) or PP (polypropylene) can be used. The surface of the film may be plain or matted.

  When providing a protective film on a relief forming layer, the protective film must be peelable.

  When the protective film cannot be peeled or when it is difficult to adhere to the relief forming layer, a slip coat layer may be provided between both layers.

  The material used for the slip coat layer is a resin that can be dissolved or dispersed in water, such as polyvinyl alcohol, polyvinyl acetate, partially saponified polyvinyl alcohol, hydroxyalkyl cellulose, alkyl cellulose, polyamide resin, etc. It is preferable that Of these, partially saponified polyvinyl alcohol having a saponification degree of 60 mol% to 99 mol%, hydroxyalkyl cellulose having 1 to 5 carbon atoms in the alkyl group, and alkyl cellulose are particularly preferably used from the viewpoint of tackiness.

  When peeling the protective film from the relief forming layer (and slip coat layer) / protective film at a rate of 200 mm / min, the peel force per 1 cm is preferably 5 to 200 mN / cm, more preferably 10 to 150 mN / cm. preferable. If it is 5 mN / cm or more, it can work without peeling off the protective film during the work, and if it is 200 mN / cm or less, the protective film can be peeled without difficulty.

-Preparation of relief printing plate precursor for laser engraving-
Next, a method for producing a relief printing plate precursor for laser engraving will be described.
Formation of the relief forming layer in the relief printing plate precursor for laser engraving is not particularly limited. For example, a relief forming layer coating liquid composition (resin composition for laser engraving) is prepared, and this relief forming layer is prepared. The method of melt-extruding on a support after removing a solvent from the coating liquid composition for coating is mentioned. Alternatively, a method of casting the relief forming layer coating solution composition on a support and drying it in an oven to remove the solvent from the coating solution composition may be used.
Thereafter, a protective film may be laminated on the relief forming layer as necessary. Lamination can be performed by pressure-bonding the protective film and the relief forming layer with a heated calendar roll or the like, or by bringing the protective film into close contact with the relief forming layer impregnated with a small amount of solvent on the surface.
When using a protective film, you may take the method of laminating | stacking a relief formation layer on a protective film first, and laminating a support body then.
When providing an adhesive layer, it can respond by using the support body which apply | coated the adhesive layer. When providing a slip coat layer, it can respond by using the protective film which apply | coated the slip coat layer.

  The coating composition for the relief forming layer is produced, for example, by dissolving a binder polymer and, as an optional component, a photothermal conversion agent and a plasticizer in an appropriate solvent, and then dissolving a polymerizable compound and a polymerization initiator. it can.

  Since most of the solvent components need to be removed at the stage of producing the relief printing plate precursor, low-molecular alcohols (e.g., methanol, ethanol, n-propanol, isopropanol, propylene glycol monomethyl ether, which are easily volatile) are used as the solvent. Etc.) and the total addition amount of the solvent is preferably minimized. The amount of the solvent added can be suppressed by raising the temperature of the system, but if the temperature is too high, the polymerizable compound is likely to undergo a polymerization reaction, so that the coating after the addition of the polymerizable compound and / or polymerization initiator is performed. The preparation temperature of the liquid composition is preferably 30 ° C to 80 ° C.

  Here, in the present invention, in the case of a relief printing plate precursor for laser engraving, as described above, it refers to the state in which the relief forming layer is crosslinked. In the method of crosslinking the relief forming layer, it is preferable to perform a step of crosslinking the relief forming layer by irradiation with actinic rays and / or heating (step (1) in the method for producing a relief printing plate of the present invention described later).

  The thickness of the relief forming layer in the relief printing plate precursor for laser engraving is preferably from 0.05 mm to 10 mm, more preferably from 0.05 mm to 7 mm, and particularly preferably from 0.05 mm to 3 mm, before and after crosslinking. is there.

[Relief printing plate and its manufacture]
The method for producing a relief printing plate of the present invention comprises (1) a step of crosslinking an uncrosslinked relief forming layer in the relief printing plate precursor for laser engraving of the present invention by at least one of irradiation with actinic rays and heating (hereinafter referred to as “ And (2) a step of laser engraving the crosslinked relief forming layer to form a relief layer (hereinafter referred to as “step (2)” as appropriate). Features. By the method for producing a relief printing plate of the present invention, the relief printing plate of the present invention having a relief layer on a support can be produced.

<Step (1)>
The relief printing plate precursor for laser engraving of the present invention has a relief forming layer cured by crosslinking as described above. In order to obtain such a relief forming layer, it is preferable to use a step of crosslinking the uncrosslinked relief forming layer in the relief printing plate precursor for laser engraving of the present invention by irradiation with active light and / or heating.
The term “crosslinking” in the present invention is a concept including a crosslinking reaction for linking binder polymers, and a relief by a polymerization reaction between polymerizable compounds having an ethylenically unsaturated bond or a reaction between a binder polymer and a polymerizable compound. It is a concept that includes the curing reaction of the formation layer.

As described above, in the step (1), crosslinking of the uncrosslinked relief forming layer is performed by irradiation with actinic rays and / or heat.
In the step (1), when the step of crosslinking by light and the step of crosslinking by heat are used in combination, these steps may be simultaneous with each other or separate steps.

Step (1) is a step of crosslinking the relief forming layer of the relief printing plate precursor for laser engraving with at least one of light and heat.
The relief forming layer preferably contains a polymerizable compound, a binder polymer, a photothermal conversion agent, and a polymerization initiator, and in step (1), the polymerizable compound is polymerized by the action of the polymerization initiator to form a crosslink. It is a process to do.
The polymerization initiator is preferably a radical generator, and the radical generator is roughly classified into a photopolymerization initiator and a thermal polymerization initiator depending on whether the trigger for generating radicals is light or heat.

When the relief forming layer contains a photopolymerization initiator, the relief forming layer can be crosslinked by irradiating the relief forming layer with an actinic ray that triggers the photopolymerization initiator (step of crosslinking by light ).
The irradiation with actinic rays is generally performed on the entire surface of the relief forming layer. Visible light, ultraviolet light, or an electron beam is mentioned as actinic light, but ultraviolet light is the most common. If the support side of the relief forming layer is the back side, the surface may only be irradiated with actinic rays, but if the support is a transparent film that transmits actinic rays, it is preferable that the back side is further irradiated with actinic rays. . When the protective film exists, the irradiation from the surface may be performed while the protective film is provided, or may be performed after the protective film is peeled off. Since polymerization inhibition may occur in the presence of oxygen, irradiation with actinic rays may be performed after the relief forming layer is covered with a vinyl chloride sheet and evacuated.

  When the relief forming layer contains a thermal polymerization initiator (the above-mentioned photopolymerization initiator can also be a thermal polymerization initiator), the relief forming layer is crosslinked by heating the relief printing plate precursor for laser engraving. (Step of crosslinking by heat). Examples of the heating means include a method of heating the printing plate precursor in a hot air oven or a far infrared oven for a predetermined time, and a method of contacting the heated roll for a predetermined time.

When step (1) is a step of crosslinking by light, an apparatus for irradiating actinic rays is relatively expensive, but the printing plate precursor does not become high temperature, so there are restrictions on the raw materials of the printing plate precursor. rare.
In the case where the step (1) is a step of crosslinking by heat, there is an advantage that an extra expensive apparatus is not required. However, since the printing plate precursor becomes high temperature, the thermoplastic polymer that becomes flexible at high temperature is being heated. The raw materials to be used must be carefully selected.
A thermal polymerization initiator may be added during the thermal crosslinking. As the thermal polymerization initiator, it can be used as a commercial thermal polymerization initiator for free radical polymerization. Examples of such a thermal polymerization initiator include a compound containing a suitable peroxide, hydroperoxide, or azo group. Representative vulcanizing agents can also be used for crosslinking. Thermal crosslinking can also be performed by adding a heat-curable resin, such as an epoxy resin, as a crosslinking component to the layer.

As a method for crosslinking the relief forming layer in the step (1), crosslinking by heat is preferable from the viewpoint that the relief forming layer can be uniformly cured (crosslinked) from the surface to the inside.
By crosslinking the relief forming layer, there is an advantage that the relief formed first after laser engraving becomes sharp, and secondly, the adhesiveness of engraving residue generated during laser engraving is suppressed. When an uncrosslinked relief forming layer is laser engraved, unintended portions are likely to melt and deform due to residual heat that has propagated around the laser irradiated portion, and a sharp relief layer may not be obtained. In addition, as a general property of a material, a material having a low molecular weight tends to be liquid rather than solid, that is, the adhesiveness tends to be strong. The engraving residue generated when engraving the relief forming layer tends to become more tacky as more low-molecular materials are used. Since the polymerizable compound which is a low molecule becomes a polymer by crosslinking, the generated engraving residue tends to have less adhesiveness.

<Step (2)>
In the method for producing a relief printing plate of the present invention, the step (1) is followed by (2) a step of forming a relief layer by laser engraving a crosslinked relief forming layer. By the method for producing a relief printing plate of the present invention, the relief printing plate of the present invention having a relief layer on a support can be produced.

In the method for producing a relief printing plate of the present invention, following the step (2), the following steps (3) to (5) may be further included as necessary.
Step (3): A step of rinsing the surface of the engraved relief layer with water or a liquid containing water as a main component (rinsing step).
Step (4): A step of drying the engraved relief layer (drying step).
Step (5): A step of imparting energy to the relief layer after engraving and further crosslinking the relief layer (post-crosslinking step).

Step (2) is a step of forming a relief layer by laser engraving the relief forming layer crosslinked in step (1). Specifically, the relief layer is formed by engraving the crosslinked relief forming layer by irradiating a laser beam corresponding to the image to be formed. Preferably, a step of controlling the laser head with a computer based on digital data of an image to be formed and scanning and irradiating the relief forming layer is exemplified.
In this step (2), an infrared laser is preferably used. When irradiated with an infrared laser, the molecules in the relief forming layer undergo molecular vibrations and generate heat. When a high-power laser such as a carbon dioxide laser or a YAG laser is used as an infrared laser, a large amount of heat is generated in the laser irradiation portion, and molecules in the relief forming layer are selectively removed by molecular cutting or ionization, that is, Sculpture is made. The advantage of laser engraving is that the engraving depth can be set arbitrarily, so that the structure can be controlled three-dimensionally. For example, a portion that prints fine halftone dots can be engraved shallowly or with a shoulder so that the relief does not fall down due to printing pressure, and a groove portion that prints fine cut characters is engraved deeply As a result, the ink is less likely to be buried in the groove, and it is possible to suppress the crushing of the extracted characters.
In particular, when engraving with an infrared laser corresponding to the absorption wavelength of the photothermal conversion agent, the relief forming layer can be selectively removed with higher sensitivity, and a relief layer having a sharp image can be obtained. As the infrared laser used in the step (2), a carbon dioxide laser or a semiconductor laser is preferable from the viewpoint of productivity, cost, and the like. In particular, a semiconductor infrared laser with a fiber is preferably used.

When engraving residue is attached to the engraving surface, a step (3) of rinsing the engraving residue by rinsing the engraving surface with water or a liquid containing water as a main component may be added. As a means of rinsing, a method of washing with tap water, a method of spraying high-pressure water, a known batch type or conveying type brush type washing machine as a developing device for photosensitive resin relief printing, the surface of engraving is mainly present For example, when the engraving residue cannot be removed, a rinsing solution to which a surfactant is added may be used.
When the step (3) of rinsing the engraved surface is performed, it is preferable to add a step (4) of drying the engraved relief forming layer and volatilizing the rinse liquid.
Furthermore, you may add the process (5) which further bridge | crosslinks a relief forming layer as needed. By performing the additional crosslinking step (5), the relief formed by engraving can be further strengthened.

As described above, the relief printing plate of the present invention having a relief layer on a support is obtained.
The thickness of the relief layer of the relief printing plate is preferably 0.05 mm or more and 10 mm or less, more preferably 0.05 mm or more from the viewpoint of satisfying various flexographic printing aptitudes such as abrasion resistance and ink transferability. It is 7 mm or less, and particularly preferably 0.05 mm or more and 0.3 mm or less.

The Shore A hardness of the relief layer of the relief printing plate is preferably 50 ° or more and 90 ° or less.
When the Shore A hardness of the relief layer is 50 ° or more, even if the fine halftone dots formed by engraving are subjected to the strong printing pressure of the relief printing press, they do not collapse and can be printed normally. In addition, when the Shore A hardness of the relief layer is 90 ° or less, it is possible to prevent faint printing in a solid portion even in flexographic printing with a printing pressure of kiss touch.
The Shore A hardness in this specification is a durometer (spring type) in which an indenter (called a push needle or indenter) is pushed into the surface of the object to be measured, and the amount of deformation (indentation depth) is measured and digitized. It is a value measured by a rubber hardness meter.

  The relief printing plate produced by the method of the present invention can be printed with oil-based ink or UV ink by a letterpress printing machine, and can also be printed with UV ink by a flexographic printing machine.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Synthesis Example: Synthesis of sulfur-containing polyfunctional monomer M-1]
In a 500 mL three-necked flask equipped with stirring blades, 3,3′-thiodipropionic acid (Wako Pure Chemical Industries, 89.10 g), 2- (dimethylamino) ethyl methacrylate (Wako Pure Chemical Industries, 157 .21 g) and toluene (100 mL) were added and stirred at room temperature. One hour later, toluene was removed under reduced pressure to obtain sulfur-containing polyfunctional monomer M-1 (243.02 g) having the following structure.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of Sulfur-Containing Polyfunctional Monomer M-2]
For the sulfur-containing polyfunctional monomer M-2 having the following structure, the same synthesis method as that for the sulfur-containing polyfunctional monomer M-1 was applied, and “3,3′-thiodipropionic acid” was converted to “3,3′- Instead of “dithiodipropionic acid”, synthesis was performed.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of sulfur-containing polyfunctional monomer M-3]
In a 100 mL eggplant flask containing a stir bar, 1,4-phenylene diisothiocyanate (Tokyo Kasei Co., Ltd., 3.00 g), glycolic acid (Tokyo Kasei Co., Ltd., 2.37 g), 2-butanone (dehydrated, summed) Mitsui Chemicals, 7.06 g) was added and stirred at 60 ° C. for 8 hours. To this solution, 2- (dimethylamino) ethyl methacrylate (manufactured by Tokyo Chemical Industry, 4.90 g) was added and stirred at room temperature for 1 hour. After the reaction, 2-butanone was removed to obtain a sulfur-containing polyfunctional monomer M-3 (10.27 g) having the following structure.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of sulfur-containing polyfunctional monomer M-4]
Thioglycolic acid (manufactured by Tokyo Chemical Industry, 6.35 g) and triethylamine (manufactured by Kanto Chemical Co., 0.09 g) were placed in a 100 mL three-necked flask equipped with a stirring blade and a condenser tube, and 2,4-tolylene diisocyanate was added. Nart (Tokyo Kasei Co., Ltd., 6.00 g) was added dropwise at room temperature. The temperature was raised to 60 ° C., stirred for 4 hours, and then returned to room temperature. To this solution, 2-butanone (Wako Pure Chemicals, 20 g) and 2- (dimethylamino) ethyl methacrylate (Tokyo Kasei, 10.84 g) were added and stirred at room temperature for 1 hour. After the reaction, 2-butanone was removed to obtain a sulfur-containing polyfunctional monomer M-4 (23.19 g) having the following structure.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of Sulfur-Containing Polyfunctional Monomer M-5]
The sulfur-containing polyfunctional monomer M-5 having the following structure was synthesized by applying the same synthesis method as that of the sulfur-containing polyfunctional monomer M-3, replacing “glycolic acid” with “thioglycolic acid”.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of sulfur-containing polyfunctional monomer M-6]
In a 500 mL three-necked flask with stirring blades, N, N, N ′, N′-tetramethyl-1,3-propanediamine (manufactured by Wako Pure Chemical, 50.00 g), 500 mL three-necked flask (Wako Pure Chemical Industries, 159.13 g) and 2-butanone (100 mL) were put in the solution, and stirred at room temperature. One hour later, toluene was removed under reduced pressure to obtain sulfur-containing polyfunctional monomer M-6 (209.13 g) having the following structure.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of sulfur-containing polyfunctional monomer M-7]
For the sulfur-containing polyfunctional monomer M-7 having the following structure, the same synthesis method as that for the sulfur-containing polyfunctional monomer M-6 was applied, and “N, N, N ′, N′-tetramethyl-1,3-propane” was applied. “Diamine” was synthesized in place of “2- (dimethylamino) ethyl acrylate”.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of sulfur-containing polyfunctional monomer M-8]
For the sulfur-containing polyfunctional monomer M-8 having the following structure, the same synthesis method as that for the sulfur-containing polyfunctional monomer M-6 was applied, and “N, N, N ′, N′-tetramethyl-1,3-propane” was applied. The “diamine” was synthesized in place of “tris (2-aminoethyl) amine”.
The structure of the obtained sulfur-containing polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of Comparative Multifunctional Monomer C-1]
In a 500 mL three-necked flask equipped with a stirring blade and a condenser tube, pimelic acid (manufactured by Wako Pure Chemical, 80.09 g), glycidyl methacrylate (manufactured by Wako Pure Chemical, 156.26 g), 1-methoxy-2- Propanol (manufactured by Nippon Emulsifier Co., Ltd., 27.78 g), tetraethylammonium bromide (manufactured by Tokyo Chemical Industry, 4.20 g), 4-hydroxy-2,2,6,6-tetramethylpyridine 1-oxyl free radical (Tokyo Kasei) Made, 0.50 g) and stirred at 80 ° C. for 4 hours. To this solution, water (500 g) and ethyl acetate (500 g) were added, transferred to a separatory funnel and stirred vigorously, and then the aqueous layer was removed. Subsequently, a saturated aqueous sodium carbonate solution (200 g) was added and stirred vigorously. The aqueous layer was removed. Subsequently, saturated brine (200 g) was added and stirred vigorously, and then the aqueous layer was removed. After the organic layer was transferred to a 1 L Erlenmeyer flask, magnesium sulfate (100 g) was added and dried. Magnesium sulfate was removed by filtration and ethyl acetate was removed under reduced pressure to obtain a comparative polyfunctional monomer C-1 (222.23 g) having the following structure.
The structure of the obtained comparative polyfunctional monomer was identified by ¹ H NMR.

[Synthesis Example: Synthesis of Comparative Multifunctional Monomer C-2]
For the comparative polyfunctional monomer C-2 having the following structure, the same synthesis method as that for the sulfur-containing polyfunctional monomer M-1 was applied, and “3,3′-dithiodipropionic acid” was replaced with “pimelic acid”. And synthesized.
The structure of the obtained polyfunctional monomer for comparison was identified by ¹ H NMR.

[Example 1]
1. Preparation of resin composition for laser engraving In a three-necked flask equipped with stirring blades and a cooling tube, 40 g of GOHSENAL T-215 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., PVA derivative) as a binder polymer, kettle as a photothermal conversion agent 0.75 g of Chain Black EC600JD (carbon black, manufactured by Lion Corporation), 20 g of diethylene glycol as a plasticizer, 35 g of water and 12 g of ethanol as a solvent were added and heated at 70 ° C. for 120 minutes with stirring to dissolve the polymer. Further, 28 g of the sulfur-containing polyfunctional monomer M-1 synthesized as described above and 1.6 g of perbutyl Z (manufactured by NOF Corporation) as a polymerization initiator are added and stirred for 30 minutes, and have fluidity. Laser engraving resin composition 1 (relief-forming layer coating solution composition) was obtained.

2. Preparation of relief printing plate precursor for laser engraving A spacer (frame) of a predetermined thickness is placed on a PET substrate, and the resin composition 1 for laser engraving obtained above is gently cast so as not to flow out of the spacer (frame). Then, it was dried in an oven at 70 ° C. for 3 hours to provide a relief forming layer having a thickness of about 1 mm.
The obtained relief forming layer was heated at 100 ° C. for 2.5 hours to thermally crosslink the relief forming layer, whereby a relief printing plate precursor 1 for laser engraving was obtained.

3. Preparation of relief printing plate “FD-100” (manufactured by Tosei Electrobeam Co., Ltd.) equipped with a semiconductor laser with a maximum output of 16 W (laser oscillation wavelength 840 nm) as a near-infrared laser engraving machine for the relief forming layer after crosslinking. ), The engraving conditions are set to laser output: 15 W, scanning speed: 100 mm / second, pitch interval: 0.15 mm, and a 2 cm square solid part is engraved to form a relief layer, and a relief printing plate 1 was obtained.

The thickness of the relief layer of the relief printing plate 1 was 1.32 mm.
Moreover, when the Shore A hardness of the relief layer was measured by the above-mentioned measuring method, it was 63 °. In addition, the measurement of the Shore hardness A of a relief layer was similarly performed also in each Example and comparative example which are mentioned later.

[Examples 2 to 8, Comparative Examples 1 and 2]
For laser engraving in the same manner as in Example 1 except that the “sulfur-containing polyfunctional monomer M-1” used in Example 1 was changed to the following polyfunctional monomer to prepare a resin composition for laser engraving. After producing the relief printing plate precursor, relief printing plates 2 to 8, C1, and C2 were produced from the relief printing plate precursor for laser engraving.

Example 2: Sulfur-containing polyfunctional monomer M-2
Example 3: Sulfur-containing polyfunctional monomer M-3
Example 4: Sulfur-containing polyfunctional monomer M-4
Example 5: Sulfur-containing polyfunctional monomer M-5
Example 6: Sulfur-containing polyfunctional monomer M-6
Example 7: Sulfur-containing polyfunctional monomer M-7
Example 8: Sulfur-containing polyfunctional monomer M-8
Comparative Example 1: Comparative multifunctional monomer C-1
Comparative Example 2: Comparative multifunctional monomer C-2
Here, the sulfur-containing polyfunctional monomer used in Examples 2 to 8 and the comparative polyfunctional monomer used in Comparative Examples 1 and 2 are compounds synthesized in the aforementioned synthesis examples.

  The thicknesses of the relief layers and Shore A hardness of the obtained relief printing plates 2 to 8, C1 and C2 are as shown in Table 1 below.

[Example 9]
Except that the resin composition for laser engraving was prepared by changing the “Gosenal T-215 which is a binder polymer” used in Example 1 to “Denkabutyral # 3000-2 (manufactured by Denki Kagaku Kogyo)” In the same manner as in No. 1, a relief printing plate precursor for laser engraving was prepared, and then a relief printing plate 9 was prepared from the relief printing plate precursor for laser engraving.
The thickness of the relief layer and the Shore A hardness of the obtained relief printing plate 9 are as shown in Table 1 below.

[Example 10]
A resin composition for laser engraving was prepared by changing “Ketjen Black EC600JD (carbon black), which is a photothermal conversion agent” used in Example 1, to “ADS820HO (cyanine compound, manufactured by American Die Source)”. Except that, a relief printing plate precursor for laser engraving was prepared in the same manner as in Example 1, and then a relief printing plate 10 was prepared from the relief printing plate precursor for laser engraving.
The thickness of the relief layer and the Shore A hardness of the obtained relief printing plate 10 are as shown in Table 1 below.

[Example 11]
Except that “Ketjen Black EC600JD (carbon black) as a photothermal conversion agent” used in Example 1 was changed to “D99-009 (phthalocyanine compound, manufactured by Yamamoto Kasei)” to prepare a resin composition for laser engraving. In the same manner as in Example 1, after producing a relief printing plate precursor for laser engraving, a relief printing plate 11 was produced from the relief printing plate precursor for laser engraving.
The thickness of the relief layer and the Shore A hardness of the obtained relief printing plate 11 are as shown in Table 1 below.

[Example 12]
Except that “Perbutyl Z as a polymerization initiator” used in Example 1 was changed to “V-30 (azo compound, manufactured by Wako Pure Chemical Industries)”, a resin composition for laser engraving was prepared. In the same manner as in No. 1, a relief printing plate precursor for laser engraving was prepared, and then a relief printing plate 12 was prepared from the relief printing plate precursor for laser engraving.
The thickness of the relief layer and the Shore A hardness of the obtained relief printing plate 12 are as shown in Table 1 below.

[Examples 13 to 24, Comparative Examples 3 and 4]
In Examples 1 to 12 and Comparative Examples 1 and 2, the “near-infrared laser engraving machine” used in producing the relief printing plate was changed to “the following carbon dioxide laser engraving machine” and changed as follows. Relief printing plates 13 to 24, C3, and C4 were prepared in the same manner as in Example 1 except that laser engraving was performed.
That is, “CO ₂ laser marker ML-Z9500” (manufactured by Keyence Corporation) equipped with a carbon dioxide laser with a maximum output of 30 W was used as a carbon dioxide laser engraving machine. Engraving conditions were set such that the laser output was 15 W, the scanning speed was 100 mm / second, and the pitch interval was 0.15 mm, and a solid portion of 2 cm square was engraved to obtain a relief printing plate.
Here, the thickness of the relief layer and the Shore A hardness of the obtained relief printing plates 13 to 24, C3, and C4 are as shown in Table 1 below.

<Evaluation>
-Sculpture depth-
The “engraving depth” of the relief layers of the relief printing plates 1 to 24 and C1 to C4 was measured as follows. Here, “sculpture depth” refers to the difference between the engraved position (height) and the unengraved position (height) when the cross section of the relief layer is observed. The “engraving depth” in this example was measured by observing the cross section of the relief layer with an ultra-deep color 3D shape measuring microscope VK9510 (manufactured by Keyence Corporation). A large engraving depth means high engraving sensitivity. The results are shown in Table 1.

  As shown in Table 1, the relief printing plate of the example produced using the resin composition for laser engraving containing the (A) sulfur-containing polyfunctional monomer in the present invention is used regardless of the type of engraving laser. (A) It turns out that engraving depth is larger than the relief printing plate of the comparative example using the comparative polyfunctional monomer of the structure different from a sulfur-containing polyfunctional monomer. This confirmed that the engraving sensitivity of the resin composition for laser engraving prepared in Examples was high.

Claims (15)

  (A) a polyfunctional polymerizable compound having two or more ethylenically unsaturated bonds, a carbon-sulfur bond and an ionic bond at a site connecting two ethylenically unsaturated bonds, and (B ) A resin composition for laser engraving containing at least a binder polymer. In the (A) polyfunctional polymerizable compound, the carbon-sulfur bond is -C-S-, -C-SS-, -NH (C = S) O-, -NH (C = O) S-,- The resin composition for laser engraving according to claim 1, which is at least one unit selected from NH (C═S) S— and —C—SO ₂ —. In (A) the polyfunctional polymerizable compound, ionic _{^{bond, * -CO-O -, *}} -SO 2 -O -, * -PO 3 -, and selected from the structures represented by the following general formula (1) 3. The laser engraving according to claim 1, comprising: one kind of anion moiety and one kind of cation moiety selected from the structures represented by the following general formulas (2) to (4): Resin composition.

(In the general formulas (1) to (4), R ^{1 to} R ⁸ are each independently a hydrogen atom, alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, or heterocyclic group. And at least two of R ^{2 to} R ⁴ may be linked to form a ring, at least two of R ^{5 to} R ⁷ may be linked to form a ring, and R ⁸ and R ⁹ May be linked to form a ring.) In the (A) polyfunctional polymerizable compound, at least one of the partial structures containing the ethylenically unsaturated bond is a partial structure represented by any one of the following general formulas (5) to (7). The resin composition for laser engraving according to any one of claims 3 to 4.

(In the general formulas (5) to (7), R ^{10 to} R ²⁰ each independently represents a hydrogen atom or a monovalent substituent, and X, Y, and Z each independently represent an oxygen atom. , A sulfur atom, — (N—R ²¹ ) —, a sulfonyl group, and R ²¹ represents a hydrogen atom or a monovalent organic group.)   (C) The resin composition for laser engraving according to any one of claims 1 to 4, further comprising a photothermal conversion agent capable of absorbing light having a wavelength of 700 nm to 1300 nm.   The resin composition for laser engraving according to any one of claims 1 to 5, which is cured by at least one of light and heat.   The resin composition for laser engraving according to any one of claims 1 to 6, which is cured by heat.   The image forming material which has an image forming layer which consists of a resin composition for laser engraving of any one of Claims 1-7 on a support body.   The image forming material according to claim 8, wherein the image forming layer is cured by at least one of light and heat.   A relief printing plate precursor for laser engraving having a relief forming layer comprising the resin composition for laser engraving according to any one of claims 1 to 7. (1) a step of crosslinking the relief forming layer in the relief printing plate precursor for laser engraving according to claim 10 by at least one of light and heat; and
(2) forming a relief layer by laser engraving a crosslinked relief forming layer;
A method for producing a relief printing plate comprising   The method for producing a relief printing plate according to claim 11, wherein the step (1) is a step of crosslinking the relief forming layer with heat.   The relief printing plate which has a relief layer manufactured by the manufacturing method of the relief printing plate of Claim 11 or Claim 12.   The relief printing plate according to claim 13, wherein the thickness of the relief layer is from 0.05 mm to 10 mm.   The relief printing plate according to claim 13 or 14, wherein the Shore A hardness of the relief layer is from 50 ° to 90 °.