WO2014034767A1

WO2014034767A1 - Resin composition for laser engraving, relief printing original plate for laser engraving, method for producing relief printing original plate for laser engraving, relief printing plate, and method for producing relief printing plate

Info

Publication number: WO2014034767A1
Application number: PCT/JP2013/073115
Authority: WO
Inventors: 佑介小沢
Original assignee: 富士フイルム株式会社
Priority date: 2012-08-31
Filing date: 2013-08-29
Publication date: 2014-03-06

Abstract

A purpose of the present invention is to provide a resin composition for laser engraving, which is capable of providing a relief printing plate that has excellent film uniformity and excellent solvent-borne ink resistance. Another purpose of the present invention is to provide: a relief printing original plate for laser engraving, which is obtained using the resin composition for laser engraving; a method for producing the relief printing original plate for laser engraving; a relief printing plate; and a method for producing the relief printing plate. A resin composition for laser engraving of the present invention is characterized by containing: (component (A)) a binder polymer which is a plastomer at 20°C and has an SP value of from 7.0 to 9.6 (inclusive); (component (B)) a compound that has a hydrophobic moiety; (component (C)) a polymerizable compound; and (component (D)) a thermal polymerization initiator. This resin composition for laser engraving is also characterized in that: the hydrophobic moiety of component (B) is a hydrocarbon group having 15 or more carbon atoms; and the ratio of the content (mass) of component (B) relative to the content (mass) of component (A) is 0.01-0.5.

Description

Resin composition for laser engraving, relief printing plate precursor for laser engraving and method for producing the same, and relief printing plate and plate making method therefor

The present invention relates to a resin composition for laser engraving, a relief printing plate precursor for laser engraving and a production method thereof, and a relief printing plate and a plate making method thereof.

Many so-called “direct engraving CTP methods” have been proposed in which a relief forming layer is directly engraved with a laser to make a plate. In this method, the flexographic printing plate precursor is directly irradiated with a laser to cause thermal decomposition and volatilization by photothermal conversion, thereby forming recesses. Unlike the relief formation using the original film, the direct engraving CTP method can freely control the relief shape. 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, etc. Is also possible.

Patent Document 1 has one or more (Component A) condensable groups for the purpose of obtaining a relief printing plate that is excellent in composition uniformity and toughness of the obtained film and has a small size dot breakage, And a compound having at least one radical chain transfer group, (Component B) a radical polymerizable compound, (Component C) a radical polymerization initiator, and (Component D) a binder polymer. A resin composition is disclosed.
Patent Document 2 aims to provide a resin composition for laser engraving that can provide a relief printing plate precursor that is excellent in film uniformity and that is excellent in engraving sensitivity in laser engraving and reproducibility of high-definition images. (Component A) one or more cross-linking agents selected from the group consisting of polyfunctional amine compounds, polyfunctional methylol compounds, polyfunctional aldehyde compounds, and polyvalent metal salts, and (Component B) Component A and A resin composition for laser engraving is disclosed, which contains polyvinyl alcohol having a functional group capable of reacting.
Further, Patent Document 3 discloses a laser engraving which is excellent in rinsing property of engraving residue generated during laser engraving and engraving sensitivity in laser engraving, and can suppress unpleasant odor generated during the production of relief printing plate precursors and laser engraving. (A) a crosslinking agent having two or more crosslinkable groups, (b) a polymer having a reactive group capable of reacting with the crosslinkable group, and (c) a fragrance. There is disclosed a resin composition for laser engraving characterized by containing.

JP 2012-30588 A JP 2012-30368 A JP 2011-63014 A

An object of the present invention is to provide a resin composition for laser engraving which can provide a relief printing plate having excellent film uniformity and solvent ink resistance. Furthermore, it aims at providing the relief printing plate precursor for laser engraving obtained using the said resin composition for laser engraving, its manufacturing method, a relief printing plate, and its plate making method.

The above-mentioned problems of the present invention have been solved by means described in the following <1>, <9> to <11>, and <13> to <15>. It is described below together with <2> to <8> and <12> which are preferred embodiments.
<1> (Component A) a binder polymer having an SP value of 7.0 or more and 9.6 or less and a plastomer at 20 ° C., (Component B) a compound having a hydrophobic site, (Component C) a polymerizable compound, and (Component D) A thermal polymerization initiator is contained, the hydrophobic part of Component B is a hydrocarbon group having 15 or more carbon atoms, and the content (mass) of Component B / the content (mass) of Component A is 0. A resin composition for laser engraving characterized by being from 01 to 0.5,
<2> The resin composition for laser engraving according to <1>, wherein component A is polyurethane acrylate,
<3> The resin composition for laser engraving according to <1> or <2>, wherein the component A has a polar group,
<4> The resin composition for laser engraving according to any one of <1> to <3>, wherein Component B has a polar group,
<5> The resin composition for laser engraving according to any one of <1> to <4>, wherein Component B has at least one selected from the group consisting of an ester bond, a carboxy group, and a hydroxy group. ,
<6> (Component E) The resin composition for laser engraving according to any one of <1> to <5>, further containing a photothermal conversion agent,
<7> The resin composition for laser engraving according to <6>, wherein Component E is carbon black,
<8> (Component F) The resin composition for laser engraving according to any one of <1> to <7>, further containing a compound having at least one of a hydrolyzable silyl group and a silanol group,
<9> A relief printing plate for laser engraving comprising a crosslinked relief-forming layer obtained by crosslinking the relief-forming layer comprising the resin composition for laser engraving according to any one of <1> to <8> with light and / or heat. Original,
<10> A layer forming step of forming a relief forming layer comprising the resin composition for laser engraving according to any one of <1> to <8>, and the relief forming layer is crosslinked by light and / or heat A crosslinking printing step for obtaining a relief printing plate precursor having a crosslinked relief forming layer, and a method for producing a relief printing plate precursor for laser engraving,
<11> A relief printing plate for laser engraving having a crosslinked relief forming layer obtained by crosslinking the relief forming layer comprising the resin composition for laser engraving according to any one of <1> to <8> with light and / or heat. A method for making a relief printing plate, comprising a step of obtaining an original plate, and a engraving step of laser engraving a relief printing plate precursor having the crosslinked relief forming layer to form a relief layer,
<12> The method for making a relief printing plate according to <11>, wherein the laser engraving is performed with a semiconductor laser,
<13> Relief printing plate making comprising: a step of preparing a relief printing plate precursor for laser engraving according to <9>; and a engraving step of laser engraving the crosslinked relief forming layer to form a relief forming layer Method,
<14> A relief printing plate having a relief layer produced by the method for making a relief printing plate according to any one of <11> to <13>,
<15> Use of the resin composition for laser engraving according to any one of <1> to <8> in a relief forming layer of a relief printing plate precursor for laser engraving.

According to the present invention, there is provided a resin composition for laser engraving that provides a relief printing plate having excellent film uniformity and excellent solvent ink resistance. Furthermore, a relief printing plate precursor for laser engraving obtained using the resin composition for laser engraving and a method for producing the same, a relief printing plate and a plate making method for the same are provided.

Hereinafter, the present invention will be described in detail.
In the present invention, the description of “lower limit to upper limit” representing the numerical range represents “lower limit or higher and lower limit or lower”, and the description of “upper limit to lower limit” represents “lower limit or higher and lower limit or higher”. That is, it represents a numerical range including an upper limit and a lower limit. In addition, “(Component A) a binder polymer having an SP value of 7.0 or more and 9.6 or less and being a plastomer at 20 ° C.” or the like is also simply referred to as “Component A” or the like.
Further, “parts by mass” and “% by mass” have the same meanings as “parts by weight” and “% by weight”, respectively, and “carboxy group” and “hydroxy group” are respectively “carboxyl group” and “hydroxyl group”. Is synonymous with.
In the present invention, a combination of preferable embodiments described below is a more preferable embodiment.

(Resin composition for laser engraving)
The resin composition for laser engraving of the present invention (hereinafter also simply referred to as “resin composition”) has a SP value of 7.0 to 9.6 and is a plastomer at 20 ° C. , (Component B) a compound having a hydrophobic site, (Component C) a polymerizable compound, and (Component D) a thermal polymerization initiator, wherein the hydrophobic site of Component B is a hydrocarbon group having 15 or more carbon atoms The content (mass) of component B / content (mass) of component A is 0.01 to 0.5.
The action mechanism in the present invention is estimated as follows.
Since the binder polymer having an SP value of 7.0 or more and 9.6 or less has low polarity, the intermolecular force is small, so many of them have a low glass transition temperature (Tg). Among them, in the present invention, 20 ° C. A binder polymer that is a plastomer is used.
In the present invention, “plastomer” means that it is easily fluidly deformed by heating and is cooled as described in “New Polymer Dictionary” edited by the Society of Polymer Science, Japan (Asakura Shoten, published in 1988). It means a polymer having the property that it can be solidified into a deformed shape. Plastomer is a term for an elastomer (having the property of instantly deforming according to the external force when an external force is applied and restoring the original shape in a short time when the external force is removed). It does not show such elastic deformation and easily plastically deforms.
In the present invention, when the original size is 100%, the plastomer can be deformed to 200% with a small external force at room temperature (20 ° C.) and does not return to 130% or less even when the external force is removed. Means things. In more detail, based on the tensile permanent strain test of JIS K 6262-1997, it is possible to extend to twice the distance between the marked lines before tension of the I-shaped test piece in a tensile test at 20 ° C., and It means a polymer having a tensile permanent set of 30% or more after 5 minutes after being held for 5 minutes when stretched to twice the distance between the marked lines before tension, and after removing the tensile external force.
In the case of a polymer that cannot be measured as described above, a polymer that does not deform and does not return to its original shape without applying external force corresponds to a plastomer, for example, a candy-like, oily, or liquid resin.
Furthermore, in the present invention, the plastomer has a glass transition temperature (Tg) of the polymer of less than 20 ° C., and in the case of a polymer having two or more Tg, all Tg is less than 20 ° C.

As a result of intensive studies, the present inventors have developed a flexographic printing plate using a binder polymer that is a plastomer having an SP value of 7.0 or more and 9.6 or less, and the binder polymer itself has a low viscosity. Therefore, it has been found that the coating solution also has a low viscosity, hot flow occurs in the drying process, and the uniformity of the film thickness is impaired. In the present invention, in order to improve the reduction in the viscosity of the coating solution, an attempt was made to add various compounds having a thickening action.
When a compound having a hydrophobic site is added, as the molecular weight of the hydrophobic site increases, aggregation of the hydrophobic sites is likely to occur, and this aggregate is entangled with the binder polymer chain or interacts with the binder polymer chain. It was found that a thickening effect was developed. In the present invention, a thickening effect was exhibited by adding a compound having a hydrocarbon group having 15 or more carbon atoms. This is because, in the present invention, the polarity of the hydrocarbon group having 15 or more carbon atoms and the polarity of the binder polymer are close, the interaction with the binder polymer chain is increased, and the thickening effect is effectively expressed. .

Moreover, it turned out that the tolerance with respect to a solvent improves as an unexpected effect. Since the SP value of the binder polymer is low, it is considered that the penetration of the solvent ink can be suppressed and the elution of the component B is suppressed, but the mechanism relating to the improvement of the solvent resistance is not clear.
Furthermore, as an unexpected effect, when the component A and the component B have a polar group, the rinsing property is improved. When a plastomer having a low elastic modulus is used as the binder polymer, the engraving residue becomes a highly viscous liquid and the rinsing property tends to be poor. However, in the present invention, when the component A and the component B contained in the engraving residue have a polar group, it is considered that the polar group attracts water and the rinsing property is improved.
As described above, by using the resin composition for laser engraving containing components A to D, a relief printing plate precursor and a relief printing plate excellent in film uniformity and solvent ink resistance can be obtained.

The resin composition for laser engraving of the present invention is not particularly limited other than the relief forming layer application of the relief printing plate precursor subjected to laser engraving, and can be widely applied to other applications. For example, not only the relief forming layer of the printing plate precursor that forms the convex relief described in detail below by laser engraving, but also other products that form irregularities and openings on the surface, such as intaglio, stencil, stamp, etc. The present invention can be applied to the formation of various printing plates and various molded articles on which images are formed by laser engraving.
Especially, it is a preferable aspect to apply to formation of the relief forming layer provided on a suitable support body.

In the present specification, regarding the description of the relief printing plate precursor, an image forming layer used for laser engraving is a flat surface and an uncrosslinked crosslinkable layer is referred to as a relief forming layer. A layer obtained by crosslinking the layers is referred to as a crosslinked relief forming layer, and a layer in which irregularities are formed on the surface by laser engraving is referred to as a relief layer.
Hereinafter, the components of the resin composition for laser engraving will be described.

(Component A) SP polymer having an SP value of 7.0 or more and 9.6 or less and a plastomer at 20 ° C. The resin composition for laser engraving of the present invention has (Component A) an SP value of 7.0 or more and 9. It contains a binder polymer that is 6 or less and is a plastomer at 20 ° C.
Here, the SP value is a solubility parameter, and is a parameter calculated by the Okitsu method (Journal of the Adhesion Society of Japan Vol. 29, No. 5 (1993)). The SP value is obtained by integrating the molar attractive constants of each atomic group of the compound and dividing by the molar volume.
In the present invention, the SP value is 7.0 or more and 9.6 or less. When the SP value is less than 7.0, the water rinsing property of engraving residue decreases. Moreover, when SP value exceeds 9.6, the tolerance with respect to a solvent will fall.
The SP value of Component A is 7.0 to 9.6, preferably 7.5 to 9.0, and more preferably 7.5 to 8.5.

Since the SP value of component A can be adjusted by the combination of raw materials at the time of synthesis, there is no particular restriction on the skeleton of the binder polymer. A binder polymer having a skeleton having a low SP value such as a (polybutadiene) skeleton, a polybutadiene skeleton, or a siloxane skeleton is preferred. Moreover, the polyester diol obtained by dehydrating and condensing an aliphatic diol and an aliphatic dicarboxylic acid also has a relatively low SP value. Among these, the component A particularly preferably has at least a hydrogenated polybutadiene skeleton or a siloxane skeleton.
In the present invention, the component A preferably contains 10% by mass or more, more preferably 20% by mass or more, and more preferably 25% by mass of the monomer unit that gives a skeleton having a low SP value. % Or more is more preferable, and 30% by mass or more is particularly preferable. Although an upper limit is not specifically limited, It is preferable that it is 99 mass% or less, It is more preferable that it is 96 mass% or less, It is still more preferable that it is 93 mass% or less.

Component A preferably has a crosslinkable group from the viewpoint of toughness, more preferably a compound having a polymerizable group such as acrylate, methacrylate, polyurethane acrylate (urethane acrylate polymer), and is polyurethane acrylate. Is more preferable.
That is, component A is particularly preferably a polymer obtained by copolymerizing an isocyanate compound, a diol compound, and an acrylate compound. As the diol compound, a compound having a skeleton having a low SP value such as a hydrogenated polybutadiene skeleton, a polybutadiene skeleton, or a siloxane skeleton is preferably used. Moreover, it is preferable to use the compound which has a hydroxyl group and an acryloyl group or an isocyanato group and an acryloyl group as an acrylate compound.
Component A may acrylate the terminal after polymerizing an isocyanate compound and a diol compound to synthesize a polyurethane, or may polymerize an isocyanate compound, a diol compound, and an acrylate compound.

Moreover, it is preferable that the component A has a polar group from a rinse property viewpoint. Polar groups containing atoms that are easily hydrated and have high electronegativity are preferred. In particular, Component A preferably has a polar group in the repeating unit of the main chain. That is, it is preferable to have a polar linking group in the repeating unit of the main chain.
Specifically, preferred polar groups include amino groups, carbonyl groups, carboxyl groups, ester bonds, amide bonds, urethane bonds, urea bonds, carbonate bonds, nitro groups, and the like. Among these, component A preferably has a urethane bond or an ester bond, and particularly preferably has a urethane bond.

In the present invention, component A is a plastomer. When component A is a plastomer, a crosslinked elastomer can be produced without using a plasticizer, and a decrease in solvent resistance due to elution of the plasticizer into the solvent can be suppressed.
The definition of plastomer is as described above.
In the present invention, the viscosity of Component A at 60 ° C. is preferably 10 mPa · s to 1,000,000 mPa · s, more preferably 50 mPa · s to 300,000 mPa · s. When the viscosity is within this range, the resin composition can be easily formed on a sheet-like or cylindrical printing plate precursor, and the process is simple. In the present invention, when the component A is a plastomer, when the printing plate precursor for laser engraving obtained therefrom is formed into a sheet or cylinder, good thickness accuracy and dimensional accuracy can be achieved.
The viscosity of Component A at 60 ° C. can be measured using a capillary viscometer, a rotational viscometer, or a vibration viscometer, and is not particularly limited, but is preferably measured with a rotational viscometer.

Component A has a weight average molecular weight of 2,000 or more, preferably 2,000 to 200,000, more preferably 2,250 to 150,000, still more preferably 2,500 to 100,000, It is preferably 3,000 to 50,000. The resin composition produced using the component A having a weight average molecular weight within this range is easy to process, and the original produced by crosslinking later maintains strength, and a relief image produced from this original (relief layer) ) Is strong and can withstand repeated use. The weight average molecular weight of component A can be measured using a GPC (gel permeation chromatograph) method and determined using a standard polystyrene calibration curve.

In the resin composition of the present invention, Component A may be used alone or in combination of two or more.
The content of the component A in the resin composition is preferably 5 to 90% by mass, more preferably 15 to 85% by mass, and more preferably 30 to 80% by mass with respect to the total solid content. Is more preferable. It is preferable for the content of component A to be in the above-mentioned range because a flexible and high-strength relief layer can be obtained. In the present invention, the solid content in the resin composition is a component obtained by removing volatile components such as a solvent described later from the resin composition.

The resin composition for laser engraving of the present invention may contain a binder polymer other than Component A. Examples of the binder polymer other than Component A include non-elastomers described in JP2011-136455A, binder polymers described in JP2012-121300A, an SP value of less than 7.0, or Examples include binder polymers exceeding 9.6.
The resin composition for laser engraving of the present invention preferably contains Component A as the main component of the binder polymer (resin component), and when other binder polymer is contained, the content of Component A relative to the entire binder polymer is: It is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 95% by mass or more. The upper limit is not particularly limited.

(Component B) Compound Having Hydrophobic Site The resin composition for laser engraving of the present invention contains (Component B) a compound having a hydrophobic site. The hydrophobic part contained in Component B is a hydrocarbon group having 15 or more carbon atoms.
When the resin composition for laser engraving of the present invention contains the component B, the resin composition for laser engraving is thickened even when the component A has a low viscosity, and the film thickness uniformity of the relief forming layer is improved. . Further, as described above, the combined use with Component A improves the solvent resistance as an unexpected effect.
In general, compounds that exhibit a thickening effect are broadly classified into polymer thickeners and associative thickeners. In the present invention, the polymer thickener is not used because it may be eluted in the solvent, and the associative thickener is used. The thickening mechanism of associative thickeners is as follows: a relatively low molecular weight compound having a hydrophobic site and a hydrophilic site is physically cross-linked by associating with hydrophobic and / or hydrophilic interactions, as if it were It is thought that the system thickens by acting as a huge single molecule.

In the present invention, Component B has a hydrocarbon group having 15 or more carbon atoms as a hydrophobic site. When the number of carbon atoms is less than 15, Component B does not have sufficient hydrophobicity, and when used in combination with Component A, it is difficult to exert a sufficient thickening effect. The hydrophobic site of component B is preferably a hydrocarbon group having 17 or more carbon atoms, and more preferably a hydrocarbon group having 19 or more carbon atoms.
Here, the hydrocarbon group may be either a chain or a ring, but is preferably a chain hydrocarbon group, and m (m is an integer of 1 or more) from saturated or unsaturated hydrocarbons. A group in which a hydrogen atom is removed is more preferable. The hydrocarbon group is preferably a hydrocarbon group having a degree of saturation or unsaturation (the number of ethylenically unsaturated groups) of 1 to 4, preferably a hydrocarbon group having a degree of saturation or unsaturation of 1 to 2. More preferred.
When the hydrocarbon group is a chain hydrocarbon group, it may have a straight chain structure or a branched structure, but at least the longest carbon chain preferably has 15 or more carbon atoms, and preferably has a straight chain structure. Particularly preferred.
Moreover, said hydrocarbon group may have a substituent and a hydroxyl group is illustrated as this substituent.

Component B may have two or more hydrophobic sites having a hydrocarbon group having 15 or more carbon atoms in one molecule. In this case, the number of carbon atoms in the hydrophobic portion per molecule of component B can be increased, and a high thickening effect is obtained, which is preferable.
The number of carbon atoms of the hydrophobic site per molecule of Component B is preferably 15 to 140, more preferably 15 to 100, and still more preferably 15 to 60. When the carbon number is within the above range, a high thickening effect is obtained, the film thickness uniformity is excellent, and the solubility at the time of preparing the resin composition is excellent, which is preferable.

Examples of component B include higher fatty acids, higher alcohols, and higher fatty acid esters.
Examples of higher fatty acids include palmitic acid, stearic acid, behenic acid (behenic acid), oleic acid, 12-hydroxystearic acid, isostearic acid, linoleic acid, linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid.
Examples of higher alcohols include linear alcohols such as cetyl alcohol, stearyl alcohol, behenyl alcohol, oleyl alcohol, cetostearyl alcohol, glycerin monostearyl ether (batyl alcohol), cholesterol, phytosterol, hexyldodecanol, isostearyl alcohol, octyl. A branched chain alcohol such as dodecanol is exemplified.
Moreover, ester compounds, such as ethylene glycol fatty acid ester, propylene glycol fatty acid ester, polyglycerol fatty acid ester, glycerol fatty acid ester, can also be used. More specifically, examples of the ethylene glycol fatty acid ester include higher fatty acid esters of ethylene glycol, and examples of the higher fatty acid include the higher fatty acids described above. Examples of the ethylene glycol fatty acid ester include ethylene glycol dipalmitate, ethylene glycol distearate, ethylene glycol dibehenate, ethylene glycol dioleate, and the like.

In the present invention, component B preferably has a polar group.
The polar group is preferably a polar group containing an atom that is easily hydrated and has a high electronegativity from the viewpoint of rinsing properties, and specifically includes an amino group, a carbonyl group, a carboxyl group, an ester bond, a nitro group, a hydroxyl group, and a urea group. Examples thereof include an amino group, a carbonyl group, a carboxyl group, an ester bond, and a hydroxyl group, and a hydroxyl group, an ester bond, and a carboxyl group are more preferable.
Examples of component B having an amino group include stearylamine, oleylamine, and icosylamine.

Component B has a molecular weight (in the case of distribution, a weight average molecular weight) of less than 2,000. The molecular weight is preferably 212 to 1,500, and more preferably 240 to 1,000. It is preferable for the molecular weight to be in the above-mentioned range since the thickening effect and solubility at the time of preparing the resin composition are excellent.

Component B preferably does not contain a terminal ethylenically unsaturated group. If the terminal has an ethylenically unsaturated group, the ethylenically unsaturated group is highly reactive and forms a cross-linked structure with component C or the like at the time of cross-linking, so there is a concern that the thickening effect is weakened.
Component B may have an ethylenically unsaturated group in a site other than the end, for example, a hydrocarbon group in a hydrophobic site, but the number of ethylenically unsaturated groups in one molecule is 0 to 2, preferably 0 or 1, more preferably 0, ie, no ethylenic unsaturation.

Regarding the content, from the viewpoint of solvent resistance and thickening, in the resin composition for laser engraving, (content of component B (mass) / content of component A (mass)) is 0.01 or more and 0.5. It is as follows. If the content (mass) of component B / content (mass) of component A is less than 0.01, a sufficient thickening effect cannot be obtained. Moreover, when it exceeds 0.5, solvent resistance will fall.
The content (mass) of component B / content (mass) of component A with respect to the solid content of the resin composition is preferably 0.02 or more and 0.4 or less, and more preferably 0.1 or more and 0.3 or less.

In the resin composition of the present invention, Component B may be used alone or in combination of two or more.
The content of the component B in the resin composition is preferably 0.05 to 50% by mass, more preferably 0.1 to 40% by mass, and more preferably 0.5 to More preferably, it is 30 mass%. It is preferable for the content of component B to be in the above range because a suitable thickening effect can be obtained.

(Component C) Polymerizable Compound The resin composition for laser engraving of the present invention contains (Component C) a polymerizable compound. By containing component C, a crosslinked structure is formed, and a crosslinked relief forming layer and a relief layer that can be used as a relief printing plate are obtained.

In the present invention, Component C has a molecular weight (weight average molecular weight in the case of molecular weight distribution) of less than 2,000, preferably 1,500 or less, more preferably 1,200 or less. More preferably, it is 1,000 or less. When the molecular weight of component C is within the above range, a high crosslinking density is obtained, which is preferable.

The polymerizable compound having at least one ethylenically unsaturated bond, which is a preferred polymerizable compound used in the present invention, is selected from compounds having at least one, preferably two or more terminal ethylenically unsaturated bonds. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof.
Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, unsaturated carboxylic acid esters having nucleophilic substituents such as hydroxyl groups, amino groups, mercapto groups, amides and monofunctional or polyfunctional isocyanates, addition reaction products of epoxies, monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. In addition, an unsaturated carboxylic acid ester having an electrophilic substituent such as an isocyanato group or an epoxy group, an addition reaction product of an amide with a monofunctional or polyfunctional alcohol, an amine or a thiol, a halogen group In addition, a substituted reaction product of unsaturated carboxylic acid ester or amide with monofunctional or polyfunctional alcohol, amine or thiol having a leaving substituent such as tosyloxy 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 the ester monomer of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid 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, etc. It is done.

Methacrylic acid esters include diethylene glycol dimethacrylate, tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butane Diol dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- ( - methacryloxy-2-hydroxypropoxy) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane, tricyclodecane dimethanol dimethacrylate, and the like.

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 aforementioned 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, 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.

A urethane-based polymerizable compound produced using an addition reaction of isocyanate and hydroxyl group is also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following formula (I) to a polyisocyanate compound having two or more isocyanate groups Is mentioned.
_{CH 2 = C (R) COOCH} 2 CH (R ') OH (I)
(However, R and R ′ represent H or CH _3. )

Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-322, and 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 polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, JP-A-1-105238, etc. It is possible to obtain a photosensitive composition having an extremely excellent photosensitive speed.

Other examples include reacting polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, 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-based 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, Journal of Japan Adhesion Association vol. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

From the viewpoint of photosensitive speed, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. Further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both photosensitivity and intensity by using a compound) is also effective.

In the present invention, Component C may be used alone or in combination of two or more.
(Component C) The polymerizable compound is preferably used in the range of 0.5 to 50% by mass, more preferably 3 to 30% by mass, based on the total solid content of the resin composition for laser engraving. It is preferable for the content of component C to be in the above-mentioned range since a relief layer having a high strength can be obtained.

(Component D) Thermal Polymerization Initiator The resin composition for laser engraving of the present invention contains (Component D) a thermal polymerization initiator. By containing component D, a crosslinked structure is introduced by heating the relief forming layer, and strength that can be used as a relief printing plate precursor is obtained.
As the thermal polymerization initiator, those known to those skilled in the art can be used without limitation. Hereinafter, although the radical thermal polymerization initiator which is a preferable thermal polymerization initiator is explained in full detail, this invention is not restrict | limited by these description.

In the present invention, preferable radical thermal polymerization initiators include (a) aromatic ketones, (b) onium salt compounds, (c) organic peroxides, (d) thio compounds, and (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. 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.

(A) aromatic ketones, (b) onium salt compounds, (d) thio compounds, (e) hexaarylbiimidazole compounds, (f) ketoxime ester compounds, (g) borate compounds, (h) azinium compounds As compounds (i) metallocene compounds, (j) active ester compounds, and (k) compounds having a carbon halogen bond, the compounds listed in paragraphs 0074 to 0118 of JP-A-2008-63554 are preferably used. it can.
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) As the organic peroxide, 3,3 ′, 4,4′-tetra (tertiarybutylperoxycarbonyl) 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 (cumylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (p-isopropylcumylperoxycarbonyl) ) Benzophenone, ditertiary butyl diperoxyisophthalate, tertiary butyl peroxybenzoate Peroxide ester systems such as are preferred.

(L) Azo-based compound Preferred as a radical polymerization initiator usable in the present invention (l) As the azo-based compound, 2,2′-azobisisobutyronitrile, 2,2′-azobispropionitrile, , 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.

In this invention, a thermal-polymerization initiator may be used individually by 1 type, and can also use 2 or more types together.
The content of component D is preferably 0.001 to 15% by mass, more preferably 0.002 to 10% by mass, based on the total solid content of the resin composition for laser engraving. By making content of component D 0.001 mass% or more, the effect which added this is acquired and bridge | crosslinking of a crosslinkable relief forming layer is performed rapidly. Further, when the content is 15% by mass or less, other components are not deficient, and printing durability sufficient for use as a relief printing plate can be obtained.

(Component E) Photothermal Conversion Agent The resin composition for laser engraving of the present invention preferably contains (Component E) a photothermal conversion agent. In the present invention, the photothermal conversion agent is considered to promote thermal decomposition of the crosslinked relief layer during laser engraving by absorbing laser light and generating heat. For this reason, it is preferable to select a photothermal conversion agent that absorbs light having a laser wavelength used for engraving.

When the relief printing plate precursor for laser engraving of the present invention is used for laser engraving with a laser (YAG laser, semiconductor laser, fiber laser, surface emitting laser, etc.) emitting an infrared ray of 700 nm or more and 1,300 nm or less as a light source. Preferably component E is used as the agent. Component E is believed to absorb the laser light and generate heat to promote thermal decomposition of the crosslinked relief layer of the printing plate precursor, and to improve the sensitivity in laser engraving of the relief printing plate precursor for laser engraving of the present invention. . Therefore, the component E is preferably a compound having an absorption wavelength at 700 nm to 1,300 nm, and more preferably a compound having a maximum absorption wavelength at 700 nm to 1,300 nm.
Although it will not restrict | limit as a specific compound of the component E if it has absorption in wavelength 700nm or more and 1,300nm or less, Dye or a pigment is mentioned preferably.

Preferred examples of the dye include those described in paragraphs 0263 to 0275 of JP2010-100047.

Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

Examples of pigments 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 particularly preferable.

These pigments may be used without surface treatment or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Applications of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

Furthermore, when the photothermal conversion agent is used in a combination (condition) in which the thermal decomposition temperature is equal to or higher than the thermal decomposition temperature of the binder polymer, the engraving sensitivity tends to be higher, which is preferable.

Specific examples of the photothermal conversion agent used in the present invention include cyanine dyes such as heptamethine cyanine dyes, oxonol dyes such as pentamethine oxonol dyes, indolium dyes, benzindolinium dyes, and benzothiazolium. And phthalide compounds reacted with a colorant, a quinolinium colorant, and a developer. Not all cyanine dyes have the light absorption characteristics described above. 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.

Also, commercially available laser dyes, supersaturated absorbing dyes, and near infrared absorbing dyes can be used. For example, as a laser dye, trade marks “ADS740PP”, “ADS745HT”, “ADS760MP”, “ADS740WS”, “ADS765WS”, “ADS745NH”, “ADS790NH”, “ADS800NH” of American Dye Source (Canada), Trademarks “NK-3555”, “NK-3509”, and “NK-3519” manufactured by Hayashibara Biochemical Laboratories, Inc. can be mentioned. In addition, as the near-infrared absorbing dyes, 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 Corporation Trademarks “YKR-2200”, “YKR-2081”, “YKR-2900”, “YKR-2100”, “YKR-3071” Industries Co., Ltd., trademark "SDO-1000B", (Ltd.) Hayashibara Biochemical Laboratories, Ltd., trademark "NK-3508", mention may be made of the "NKX-114". However, it is not limited only to these.

Further, as the phthalide compound reacted with the developer, those described in Japanese Patent No. 3271226 can be used. Further, a phosphoric acid ester metal compound, for example, a complex of a phosphoric acid ester and a copper salt described in JP-A-6-345820 and WO99 / 10354 can be used. Furthermore, fine particles having a volume average particle diameter having light absorption characteristics in the near infrared region are preferably 0.3 μm or less, more preferably 0.1 μm or less, and particularly preferably 0.08 μm or less. Examples thereof include metal oxides such as yttrium oxide, tin oxide and / or indium oxide, copper oxide, and iron oxide, or metals such as gold, silver, palladium, and platinum. Furthermore, metal ions such as copper, tin, indium, yttrium, chromium, cobalt, titanium, nickel, vanadium, and rare earth elements are contained in particles such as glass having a volume average particle diameter of 5 μm or less, more preferably 1 μm or less. What was added can also be used. It can also be contained in microcapsules. In that case, the volume average particle diameter of the capsule is preferably 10 μm or less, more preferably 5 μm or less, and still more preferably 1 μm or less. What adsorb | sucked metal ions, such as copper, tin, indium, yttrium, and rare earth elements, can also be used for an ion exchanger particle. The ion exchanger particles may be resin particles or inorganic particles. Examples of the inorganic particles include amorphous zirconium phosphate, amorphous zirconium silicophosphate, amorphous zirconium hexametaphosphate, layered zirconium phosphate, reticulated zirconium phosphate, zirconium tungstate, zeolite, and the like. Examples of the resin particles include commonly used ion exchange resins and ion exchange cellulose.

As the photothermal conversion agent in the present invention, carbon black can be particularly preferably mentioned from the viewpoint of stability and photothermal conversion efficiency. Carbon black is usually used for various applications such as for color, rubber, and dry batteries, as long as there is no problem with dispersion stability in the composition constituting the relief forming layer, as well as products with standards classified by ASTM. Any carbon black used can be preferably used.
The carbon black here includes, for example, furnace black, thermal black, channel black, lamp black, acetylene black, and the like. In addition, in order to facilitate dispersion, black colorants such as carbon black use a dispersant as needed, and as a color chip or color paste previously dispersed in nitrocellulose or a binder, the relief forming layer composition 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 (dibutyl phthalate) absorption and even finer carbon black having a large specific surface area.
Examples of suitable commercially available carbon blacks include Printex U (registered trademark), Printex A (registered trademark) or Spezialschwarz 4 (registered trademark) (both manufactured by Degussa), Seast 600 ISAF-LS (Tokai Carbon Co., Ltd.) Asahi # 70 (N-300), Asahi # 80 (N-220) (Asahi Carbon Co., Ltd.) and the like.

In the present invention, carbon black having a DBP oil absorption of less than 150 ml / 100 g is preferred from the viewpoint of dispersibility in the resin composition for laser engraving.
For such selection of carbon black, for example, “Carbon Black Handbook” edited by Carbon Black Association can be referred to.
It is preferable to use carbon black having a DBP oil absorption of less than 150 ml / 100 g because good dispersibility can be obtained in the relief forming layer. On the other hand, when a carbon black having a DBP oil absorption of 150 ml / 100 g or more is used, the dispersibility in the coating solution for the relief forming layer tends to deteriorate, and the carbon black tends to agglomerate. This is undesirable because of non-uniformity. In order to prevent aggregation, it is necessary to enhance the dispersion of carbon black when preparing the coating solution.

As a method for dispersing the component E, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a paint shaker, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a Dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

The content of component E varies depending on the molecular extinction coefficient inherent to the molecule, but is preferably 0.1 to 15% by mass, more preferably 0, based on the total solid content of the resin composition for laser engraving. 0.1 to 10% by mass, more preferably 0.1 to 5% by mass.

The volume average particle diameter of Component E is preferably in the range of 0.001 μm to 10 μm, more preferably in the range of 0.05 μm to 10 μm, and particularly in the range of 0.1 μm to 7 μm. Is preferred.
The volume average particle size of Component E can be measured using a laser scattering particle size distribution measuring device.

(Component F) Compound having at least one hydrolyzable silyl group and silanol group The resin composition for laser engraving of the present invention comprises (Component F) a compound having at least one hydrolyzable silyl group and silanol group. It is preferable to contain. By containing component F, when a relief forming layer is crosslinked, a crosslinking due to a siloxane bond is also formed, and a relief printing plate having more excellent printing durability can be obtained.

The “hydrolyzable silyl group” in the compound having at least one of hydrolyzable silyl group and silanol group (component F) preferably used in the resin composition for laser engraving of the present invention is a hydrolyzable silyl group. Examples of the hydrolyzable group include an alkoxy group, a mercapto group, a halogen atom, an amide group, an acetoxy group, an amino group, and an isopropenoxy group. The silyl group is hydrolyzed to become a silanol group, and the silanol group is dehydrated and condensed to form a siloxane bond. Such a hydrolyzable silyl group or silanol group is preferably represented by the following formula (1).

In the above formula (1), at least one of R ¹ to R ³ is a water selected from the group consisting of an alkoxy group, a mercapto group, a halogen atom, an amide group, an acetoxy group, an amino group, and an isopropenoxy group. It represents a decomposable group or a hydroxyl group. The remaining R ¹ to R ³ are each independently a hydrogen atom, a halogen atom, or a monovalent organic substituent (for example, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, and an aralkyl group). To express.
In the above formula (1), the hydrolyzable group bonded to the silicon atom is particularly preferably an alkoxy group or a halogen atom, and more preferably an alkoxy group.
The alkoxy group is preferably an alkoxy group having 1 to 30 carbon atoms from the viewpoint of rinsing properties and printing durability. An alkoxy group having 1 to 15 carbon atoms is more preferable, an alkoxy group having 1 to 5 carbon atoms, particularly preferably an alkoxy group having 1 to 3 carbon atoms, and most preferably a methoxy group or an ethoxy group.
Examples of the halogen atom include F atom, Cl atom, Br atom, and I atom. From the viewpoint of ease of synthesis and stability, Cl atom and Br atom are preferable, and Cl atom is more preferable. is there.

Component F in the present invention is preferably a compound having one or more groups represented by the above formula (1), more preferably a compound having two or more. In particular, a compound having two or more hydrolyzable silyl groups is preferably used. That is, a compound having two or more silicon atoms having a hydrolyzable group bonded in the molecule is preferably used. The number of silicon atoms bonded to the hydrolyzable group contained in Component F is preferably 2 or more and 6 or less, and most preferably 2 or 3.
The hydrolyzable group can be bonded to one silicon atom in the range of 1 to 4, and the total number of hydrolyzable groups in the formula (1) is preferably in the range of 2 or 3. In particular, it is preferable that three hydrolyzable groups are bonded to a silicon atom. When two or more hydrolyzable groups are bonded to a silicon atom, they may be the same as or different from each other.

Specific examples of preferable alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, tert-butoxy, phenoxy, benzyloxy and the like. A plurality of these alkoxy groups may be used in combination, or a plurality of different alkoxy groups may be used in combination.
Examples of the alkoxysilyl group to which the alkoxy group is bonded include, for example, a trialkoxysilyl group such as a trimethoxysilyl group, a triethoxysilyl group, a triisopropoxysilyl group, a triphenoxysilyl group; a dimethoxymethylsilyl group, a diethoxymethylsilyl group And dialkoxymonoalkylsilyl groups such as methoxydimethylsilyl group and ethoxydimethylsilyl group.

Component F preferably has at least a sulfur atom, an ester bond, a urethane bond, an ether bond, a urea bond, or an imino group.
Among them, the component F preferably contains a sulfur atom from the viewpoint of crosslinkability, and from the viewpoint of engraving residue removal (rinse property), an ester bond, urethane bond, or It preferably contains an ether bond (particularly an ether bond contained in an oxyalkylene group). The component F containing a sulfur atom functions as a vulcanizing agent or a vulcanization accelerator during the vulcanization treatment, and accelerates the reaction (crosslinking) of the polymer containing the conjugated diene monomer unit. As a result, the rubber elasticity necessary for the printing plate is developed. Further, the strength of the crosslinked relief forming layer and the relief layer is improved.
Moreover, it is preferable that the component F in this invention is a compound which does not have an ethylenically unsaturated bond.

Component F in the present invention includes a compound in which a plurality of groups represented by the above formula (1) are bonded via a divalent linking group, and such a divalent linking group is effective. From the viewpoint, a linking group having a sulfide group (—S—), an imino group (—N (R) —), a urea bond, or a urethane bond (—OCON (R) — or —N (R) COO—) is preferable. R represents a hydrogen atom or a substituent. Examples of the substituent in R include an alkyl group, an aryl group, an alkenyl group, an alkynyl group, and an aralkyl group.
There is no restriction | limiting in particular as a synthesis method of the component F, It can synthesize | combine by a well-known method. As an example, a typical synthesis method of component F containing a linking group having the above specific structure is shown below.

(Synthesis method of a compound having a sulfide group as a linking group and having a hydrolyzable silyl group and / or a silanol group)
The method for synthesizing component F having a sulfide group as a linking group (hereinafter, appropriately referred to as “sulfide linking group-containing component F”) is not particularly limited. Specifically, for example, it has a halogenated hydrocarbon group. Reaction of component F and alkali sulfide, reaction of component F having mercapto group and halogenated hydrocarbon, reaction of component F having mercapto group and component F having halogenated hydrocarbon group, component F having halogenated hydrocarbon group Reaction of mercaptans with component F, reaction of component F having an ethylenically unsaturated double bond with mercaptans, reaction of component F having an ethylenically unsaturated double bond with component F having a mercapto group, ethylenically unsaturated double bond Reaction of component F having mercapto group with compound having bond, reaction of component F having ketone with mercapto group, diazonium salt and mercapto group Reaction of component F having a mercapto group, reaction of component F having a mercapto group and oxirane, reaction of component F having mercapto group and component F having oxirane group, reaction of component F having mercaptan group and oxirane group, mercapto Examples thereof include a synthesis method such as a reaction between component F having a group and aziridines.

(Method for synthesizing a compound having an imino group as a linking group and having a hydrolyzable silyl group and / or a silanol group)
The synthesis method of component F having an imino group as a linking group (hereinafter, referred to as “imino linking group-containing component F” as appropriate) is not particularly limited. Specifically, for example, component F having an amino group and Reaction of halogenated hydrocarbon, reaction of component F having amino group and component F having halogenated hydrocarbon group, reaction of component F having halogenated hydrocarbon group and amines, component F having amino group and oxiranes Reaction of component F having an amino group and component F having an oxirane group, reaction of component F having an amine group and oxirane group, reaction of component F having an amino group and aziridines, Reaction of component F having a heavy bond and amines, reaction of component F having an ethylenically unsaturated double bond and component F having an amino group, compound having an ethylenically unsaturated double bond, Reaction of component F having an mino group, reaction of a compound having an acetylenic unsaturated triple bond and component F having an amino group, reaction of component F having an imine unsaturated double bond and an organic alkali metal compound, iminity Examples of the synthesis method include a reaction between the component F having a saturated double bond and an organic alkaline earth metal compound, and a reaction between the carbonyl compound and the component F having an amino group.

(Method for synthesizing a compound having a urea bond as a linking group and having a hydrolyzable silyl group and / or a silanol group)
The synthesis method of component F having a urea bond as a linking group (hereinafter, appropriately referred to as “urea linking group-containing component F”) is not particularly limited. Specifically, for example, component F having an amino group and Examples include synthetic methods such as reaction of isocyanates, reaction of component F having an amino group and component F having isocyanate, and reaction of component F having amines and isocyanate.

Component F is preferably a compound represented by the following formula (A-1) or formula (A-2).

(In Formula (A-1) and Formula (A-2), R ^B represents an ester bond, an amide bond, a urethane bond, a urea bond, or an imino group, L ¹ represents an n-valent linking group, and L ² represents a divalent linking group, L ^s1 represents an m-valent linking group, L ³ represents a divalent linking group, n and m each independently represents an integer of 1 or more, R ¹ to R ³ each independently represents a hydrogen atom, a halogen atom or a monovalent organic substituent, provided that at least one of R ¹ to R ³ is an alkoxy group, mercapto group, halogen atom, amide group, acetoxy A hydrolyzable group selected from the group consisting of a group, an amino group and an isopropenoxy group, or a hydroxyl group.)

R ¹ ~ R ³ in the above formula (A-1) and Formula (A-2) has the same meaning as R ¹ ~ R ³ in the formula (1), and preferred ranges are also the same.
The R ^B is, from the viewpoint of rinsing properties and film strength, it is preferably an ester bond or a urethane bond, and more preferably an ester bond.
The divalent or n-valent linking group in L ¹ to L ³ is a group composed of at least one atom selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom. It is preferably a group composed of at least one atom selected from the group consisting of carbon atom, hydrogen atom, oxygen atom and sulfur atom. The number of carbon atoms of L ¹ to L ³ is preferably 2 to 60, and more preferably 2 to 30.
The m-valent linking group in L ^s1 is a group composed of a sulfur atom and at least one atom selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom. Are preferable, and an alkylene group or a group in which two or more alkylene groups, sulfide groups, and imino groups are combined is more preferable. The number of carbon atoms of L ^s1 is preferably 2 to 60, and more preferably 6 to 30.
N and m are each independently preferably an integer of 1 to 10, more preferably an integer of 2 to 10, still more preferably an integer of 2 to 6, and particularly preferably 2. preferable.
The n-valent linking group of L ¹ and / or the divalent linking group of L ² or the divalent linking group of L ³ has an ether bond from the viewpoint of the ability to remove engraving residue (rinse). It is more preferable to have an ether bond contained in the oxyalkylene group.
Among the compounds represented by formula (A-1) or formula (A-2), from the viewpoint of crosslinkability and the like, in formula (A-1), an n-valent linking group of L ¹ and / or L ² The divalent linking group is preferably a group having a sulfur atom.

Specific examples of component F applicable to the present invention are shown below. For example, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxy Silane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, p-styryltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacrylic Roxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxy Silane, N- (β-aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercapto Propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, dimethoxy-3-mercaptopropylmethylsilane, 2- (2-aminoethylthioethyl) diethoxymethylsilane, 3- (2-acetoxyethyl) Thiopropyl) dimethoxymethylsilane, 2- (2-aminoethylthioethyl) triethoxysilane, dimethoxymethyl-3- (3-phenoxypropylthiopropyl) silane, bis (triethoxysilylpropyl) disulfide, bis (tri Toxisilylpropyl) tetrasulfide, 1,4-bis (triethoxysilyl) benzene, bis (triethoxysilyl) ethane, 1,6-bis (trimethoxysilyl) hexane, 1,8-bis (triethoxysilyl) octane 1,2-bis (trimethoxysilyl) decane, bis (triethoxysilylpropyl) amine, bis (trimethoxysilylpropyl) urea, γ-chloropropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, trimethylsilanol, Examples thereof include diphenylsilanediol and triphenylsilanol. In addition, the compounds shown below are preferred, but the present invention is not limited to these compounds.

In the above formulas, R represents a partial structure selected from the following structures. When a plurality of R and R ¹ are present in the molecule, these may be the same or different from each other, and are preferably the same in terms of synthesis suitability.

In the above formulas, R represents the partial structure shown below. R ¹ has the same meaning as described above. When a plurality of R and R ¹ are present in the molecule, these may be the same or different from each other, and are preferably the same in terms of synthesis suitability.

Component F can be obtained by appropriately synthesizing, but it is preferable to use a commercially available product from the viewpoint of cost. As component F, for example, commercially available silane products and silane coupling agents commercially available from Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Co., Ltd., Momentive Performance Materials Co., Ltd., Chisso Co., Ltd., etc. Since the product corresponds to this, these commercially available products may be appropriately selected and used for the resin composition of the present invention according to the purpose.

As component F in the present invention, a partial hydrolysis condensate obtained by using one kind of compound having a hydrolyzable silyl group and / or silanol group, or a partial cohydrolysis condensate obtained by using two or more kinds Can be used. Hereinafter, these compounds may be referred to as “partial (co) hydrolysis condensates”.
Among silane compounds as partial (co) hydrolysis condensate precursors, from the viewpoint of versatility, cost, and film compatibility, it has a substituent selected from a methyl group and a phenyl group as a substituent on silicon. It is preferably a silane compound. Specifically, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane Is exemplified as a preferred precursor.
In this case, as a partial (co) hydrolysis condensate, dimers of the silane compound as described above (1 mol of water was allowed to act on 2 mol of the silane compound to remove 2 mol of alcohol to form disiloxane units. To 100-mer, preferably 2 to 50-mer, more preferably 2 to 30-mer, and a partially co-hydrolyzed condensate using two or more silane compounds as raw materials. It is also possible to use it.

In addition, as such a partial (co) hydrolysis condensate, you may use what is marketed as a silicone alkoxy oligomer (for example, it is marketed from Shin-Etsu Chemical Co., Ltd.), etc. You may use what was manufactured by removing by-products, such as alcohol and hydrochloric acid, after making the hydrolysis water of less than an equivalent react with a hydrolysable silane compound based on a conventional method. In production, for example, when using alkoxysilanes or acyloxysilanes as described above as the precursor hydrolyzable silane compound, acids such as hydrochloric acid and sulfuric acid, sodium hydroxide, hydroxide Alkaline or alkaline earth metal hydroxides such as potassium, alkaline organic substances such as triethylamine, etc. may be used as a reaction catalyst for partial hydrolysis and condensation. In the case of direct production from chlorosilanes, by-product hydrochloric acid is used as a catalyst. And water and alcohol may be reacted.

Component F in the resin composition of the present invention may be used alone or in combination of two or more.
The content of the component F contained in the resin composition of the present invention is preferably in the range of 0.1 to 80% by mass, more preferably in the range of 1 to 40% by mass in terms of solid content. Most preferably, it is in the range of 5 to 30% by mass.

(Component G) Alcohol Exchange Reaction Catalyst When component F is used in the resin composition of the present invention, it is preferable to contain (Component G) an alcohol exchange reaction catalyst in order to promote the reaction of component F.
The alcohol exchange reaction catalyst can be applied without limitation as long as it is a commonly used reaction catalyst.
Hereinafter, an acid or basic catalyst, which is a typical alcohol exchange reaction catalyst, and a metal complex catalyst will be sequentially described.

-Acid or basic catalyst-
As the catalyst, an acid or a basic compound is used as it is, or a catalyst in which it is dissolved in a solvent such as water or an organic solvent (hereinafter referred to as an acidic catalyst and a basic catalyst, respectively). The concentration at the time of dissolving in the solvent is not particularly limited, and may be appropriately selected according to the characteristics of the acid or basic compound used, the desired content of the catalyst, and the like.
The type of acidic catalyst or basic catalyst is not particularly limited. Specifically, examples of the acidic catalyst include hydrogen halides such as hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, hydrogen sulfide, perchloric acid, hydrogen peroxide, carbonic acid, Examples of the basic catalyst include carboxylic acids such as formic acid and acetic acid, substituted carboxylic acids obtained by substituting R of the structural formula represented by RCOOH with other elements or substituents, sulfonic acids such as benzenesulfonic acid, and phosphoric acid. Include ammoniacal bases such as aqueous ammonia and amines such as ethylamine and aniline. From the viewpoint of promptly promoting the alcohol exchange reaction in the layer, methanesulfonic acid, p-toluenesulfonic acid, pyridinium p-toluenesulfonate, phosphoric acid, phosphonic acid, acetic acid, 1,8-diazabicyclo [5.4.0] ] Undec-7-ene and hexamethylenetetramine are preferred, and methanesulfonic acid, p-toluenesulfonic acid, phosphoric acid, 1,8-diazabicyclo [5.4.0] undec-7-ene and hexamethylenetetramine are particularly preferred. .

-Metal complex catalyst-
The metal complex catalyst used as the alcohol exchange reaction catalyst in the present invention is preferably a metal element selected from the group consisting of groups 2, 4, 5 and 13 of the periodic table and β-diketone (acetylacetone is preferred), It is composed of an oxo or hydroxy oxygen compound selected from the group consisting of ketoesters, hydroxycarboxylic acids or esters thereof, amino alcohols, and enolic active hydrogen compounds.
Furthermore, among the constituent metal elements, group 2 elements such as Mg, Ca, Sr, and Ba, group 4 elements such as Ti and Zr, group 5 elements such as V, Nb, and Ta, and 13 such as Al and Ga. Group elements are preferred and each form a complex with excellent catalytic effect. Among them, complexes obtained from Zr, Al, or Ti are excellent, and ethyl orthotitanate is particularly preferable.
These are excellent in stability in aqueous coating solutions and in gelation promoting effect in sol-gel reaction during heat drying. Among them, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), di ( Particularly preferred are acetylacetonato) titanium complex and zirconium tris (ethylacetoacetate).

In the resin composition of the present invention, only one alcohol exchange reaction catalyst may be used, or two or more kinds may be used in combination. The content of the alcohol exchange reaction catalyst in the resin composition is preferably 0.01 to 20% by mass and more preferably 0.1 to 10% by mass with respect to the specific binder polymer having a hydroxyl group.

<Other ingredients>
To the resin composition for laser engraving of the present invention, other components suitable for its use, production method and the like can be appropriately added. Hereinafter, preferred additives will be exemplified.

<Polymerization inhibitor>
In the present invention, in addition to the above basic components, a small amount of a thermal polymerization inhibitor is added in order to prevent unnecessary thermal polymerization of a compound having an ethylenically unsaturated bond that can be polymerized during the production or storage of the composition. May be. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2′-methylenebis (4-methyl-6-t-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt, and the like.
The addition amount of the thermal polymerization inhibitor is preferably 0.01% by mass or more and 10% by mass or less with respect to the total mass of the resin composition for laser engraving.
If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to prevent polymerization inhibition due to oxygen, and a relief printing plate precursor is dried after coating on a support or the like. In this process, it may be unevenly distributed on the surface of the photosensitive layer. The addition amount of the higher fatty acid derivative is preferably 0.5% by mass or more and 15% by mass or less with respect to the total mass of the resin composition for laser engraving.

<Filler>
The filler may be an organic compound, an inorganic compound, or a mixture thereof. For example, examples of the organic compound include carbon black, carbon nanotube, fullerene, and graphite. Examples of the inorganic compound include silica, alumina, aluminum, and calcium carbonate.

<Plasticizer>
A plasticizer has the effect | action which softens the resin composition for laser engravings, and needs to have a good compatibility with a binder polymer. Examples of plasticizers include diethylene glycol, dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, and triacetyl glycerin. The amount added is preferably 60% by mass or less, and more preferably 50% by mass or less, based on the total mass.

<Colorant>
Further, a coloring agent such as a dye or a 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. As the colorant, it is particularly preferable to use a pigment. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. The addition amount of the colorant is preferably 0.5% by mass or more and 10% by mass or less with respect to the total mass of the resin composition for laser engraving.

<Co-sensitizer>
By using a certain kind of additive (hereinafter referred to as a co-sensitizer), the sensitivity at the time of photocuring the resin composition for laser engraving can be further improved. These mechanisms of action are not clear, but many are thought to be based on the following chemical processes. That is, a co-sensitizer reacts with various intermediate active species (radicals and cations) generated in the course of a photoreaction initiated by a photopolymerization initiator and a subsequent polymerization reaction, thereby generating a new active radical. Presumed. These can be broadly divided into (i) those that can be reduced to produce active radicals, (ii) those that can be oxidized to produce active radicals, and (iii) radicals that are more active by reacting with less active radicals. Can be classified as those that act as chain transfer agents, but often there is no generality as to which of these individual compounds belong. Examples of co-sensitizers that can be used in the present invention include trihalomethyl-s-triazines, trihalomethyloxadiazoles and diaryliodonium salts, triarylsulfonium salts, N-alkoxypyridinium (azinium) salts, alkylate complexes, Examples include alkylamine compounds, α-substituted methylcarbonyl compounds, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, and 2-mercaptobenzimidazoles. More specific examples of these co-sensitizers are described, for example, in JP-A-9-236913 as additives for the purpose of improving sensitivity, and these are also applied in the present invention. be able to.

Co-sensitizers can be used alone or in combination of two or more. The amount used is preferably 0.05 parts by mass or more and 100 parts by mass or less, more preferably 1 part by mass or more and 80 parts by mass or less, and further preferably 3 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polymerizable compound. Is appropriate.

(Relief printing plate precursor for laser engraving)
The first embodiment of 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.
Further, the second embodiment of the relief printing plate precursor for laser engraving of the present invention has a crosslinked relief forming layer obtained by crosslinking the relief forming layer comprising the resin composition for laser engraving of the present invention. In the present invention, the “relief printing plate precursor for laser engraving” is a state in which the relief-forming layer having a crosslinkability made of the resin composition for laser engraving is in a state before being crosslinked and cured by light or heat. Both or either one.
In the present invention, the “relief-forming layer” refers to a layer in a state before being crosslinked, that is, a layer made of the resin composition for laser engraving of the present invention, and may be dried if necessary. Good.
A “relief printing plate” is produced by laser engraving a printing plate precursor having a crosslinked relief forming layer.
In the present invention, the “crosslinked relief forming layer” refers to a layer obtained by crosslinking the relief forming layer. The above crosslinking can be performed by heat and / or light, and is preferably performed by heat. Moreover, the said bridge | crosslinking will not be specifically limited if it is reaction by which a resin composition is hardened, The bridge | crosslinking structure by reaction of component C etc. can be illustrated.
In the present invention, the “relief layer” refers to a layer engraved with a laser in a relief printing plate, that is, the crosslinked relief forming layer after laser engraving.

The relief printing plate precursor for laser engraving of the present invention has a relief forming layer made of a resin composition for laser engraving containing the above components. The (crosslinked) relief forming layer is preferably provided on the support.
The relief printing plate precursor for laser engraving further has an adhesive layer between the support and the (crosslinked) relief forming layer, if necessary, and a slip coat layer and a protective film on the (crosslinked) relief forming layer. May be.

<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 crosslinked by heat and / or light.

As a production mode of a relief printing plate using a relief printing plate precursor for laser engraving, a relief printing plate precursor having a crosslinked relief forming layer is obtained by crosslinking the relief forming layer, and then a crosslinked relief forming layer (hard relief forming layer) is used. It is preferable that the relief printing plate is produced by forming a relief layer by 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.

The relief forming layer can be formed by molding a resin composition for laser engraving having the above components for the relief forming layer into a sheet shape or a sleeve shape. The relief forming layer is usually provided on a support which will be described later. However, the relief forming layer can be directly formed on the surface of a member such as a cylinder provided in an apparatus for plate making and printing, or can be arranged and fixed there. It does not necessarily require a support.

<Support>
In the present invention, a material having flexibility and excellent dimensional stability is preferably used as the support, for example, polyethylene terephthalate film (PET), polyethylene naphthalate film (PEN), polybutylene terephthalate film. Or a polycarbonate can be mentioned preferably. The thickness of the support is preferably 50 μm or more and 350 μm or less, preferably 100 μm or more and 250 μm or less in view of the mechanical properties of the original plate, the shape stability, the handleability during printing plate making, and the like. If necessary, a known adhesive conventionally used for this kind of purpose may be provided on the surface in order to improve the adhesion between the support and the relief-forming resin layer.
Further, by performing physical and chemical treatments on the surface of the support used in the present invention, the adhesion with the relief forming resin composition layer or the adhesive layer can be improved. Examples of the physical treatment method include a sand blast method, a wet blast method in which a liquid containing particles is jetted, a corona discharge treatment method, a plasma treatment method, an ultraviolet ray or vacuum ultraviolet ray irradiation method, and the like. The chemical treatment method includes a strong acid / strong alkali treatment method, an oxidant treatment method, a coupling agent treatment method, and the like.

<Adhesive layer>
When the relief forming layer is formed on the support, an adhesive layer may be provided between the two for the purpose of enhancing the adhesive strength between the layers.
As a material (adhesive) that can be used for the adhesive layer, for example, I.I. Those described in the edition of Skeist, “Handbook of Adhesives”, the second edition (1977) can be used.

<Protective film, slip coat layer>
For the purpose of preventing scratches or dents on the surface of the relief forming layer or the surface of the crosslinked relief forming layer, a protective film may be provided on the surface of the relief forming layer or the surface of the crosslinked relief forming layer. The thickness of the protective film is preferably 25 to 500 μm, more preferably 50 to 200 μm. As the protective film, for example, a polyester film such as PET, or a polyolefin film such as PE (polyethylene) or PP (polypropylene) can be used. The surface of the film may be matted. The protective film is preferably peelable.

(Manufacturing method of relief printing plate precursor for laser engraving)
Formation of the relief forming layer in the relief printing plate precursor for laser engraving is not particularly limited. For example, a resin composition for laser engraving is prepared, and if necessary, from this coating solution composition for laser engraving. The method of melt-extruding on a support body after removing a solvent is mentioned. Alternatively, the resin composition for laser engraving may be cast on a support and dried in an oven to remove the solvent from the resin composition.
Among them, the plate making method of the relief printing plate for laser engraving of the present invention includes a layer forming step for forming a relief forming layer comprising the resin composition for laser engraving of the present invention, and the relief forming layer by light and / or heat. It is preferable that the production method includes a crosslinking step of obtaining a relief printing plate precursor that is crosslinked and has a crosslinked relief forming layer.

As a method for forming the relief printing plate precursor for laser engraving of the present invention into a sheet shape or a cylindrical shape, an existing resin molding method can be used. For example, a casting method, a method of extruding a resin from a nozzle or a die with a machine such as a pump or an extruder, adjusting the thickness with a blade, or adjusting the thickness by calendering with a roll can be exemplified. In that case, it is also possible to perform molding while heating within a range that does not deteriorate the performance of the resin. Moreover, you may perform a rolling process, a grinding process, etc. as needed. Usually, it is often formed on an underlay called a back film made of a material such as PET or nickel, but it may be formed directly on a cylinder of a printing machine. In addition, a cylindrical support made of fiber reinforced plastic (FRP), plastic, or metal can be used. The cylindrical support can be hollow with a constant thickness for weight reduction. The role of the back film or cylindrical support is to ensure the dimensional stability of the printing plate precursor. Therefore, it is necessary to select one having high dimensional stability.
Specific examples of materials include polyester resin, polyimide resin, polyamide resin, polyamideimide resin, polyetherimide resin, polybismaleimide resin, polysulfone resin, polycarbonate resin, polyphenylene ether resin, polyphenylene thioether resin, polyethersulfone resin, all Examples thereof include liquid crystal resins composed of aromatic polyester resins, wholly aromatic polyamide resins, and epoxy resins.
Further, these resins can be laminated and used. For example, a sheet or the like in which layers of polyethylene terephthalate having a thickness of 50 μm are laminated on both surfaces of a 4.5 μm thick wholly aromatic polyamide film may be used. In addition, a porous sheet, for example, a cloth formed by knitting fibers, a nonwoven fabric, a film in which pores are formed, or the like can be used as a back film. When a porous sheet is used as a back film, high relief is obtained because the relief-formed resin cured product layer and the back film are integrated by photo-curing after impregnating the relief-forming resin composition into the holes. be able to.
The fibers forming the cloth or non-woven fabric include glass fibers, alumina fibers, carbon fibers, alumina / silica fibers, boron fibers, high silicon fibers, potassium titanate fibers, sapphire fibers, and other natural fibers such as cotton and hemp. Examples thereof include semi-synthetic fibers such as fibers, rayon and acetate, and synthetic fibers such as nylon, polyester, acrylic, vinylon, polyvinyl chloride, polyolefin, polyurethane, polyimide, and aramid. Further, cellulose produced by bacteria is a highly crystalline nanofiber, and is a material capable of producing a thin nonwoven fabric with high dimensional stability.

The thickness of the relief forming layer of the printing plate precursor used for laser engraving may be arbitrarily set according to the purpose of use, but when used as a printing plate, it is preferably in the range of 0.05 mm to 10 mm. . From the printing durability of the printing plate and the ease of laser engraving, it is more preferably in the range of 0.1 mm to 7 mm. In some cases, a plurality of materials having different compositions may be stacked. The thickness of the relief forming layer of the relief printing plate precursor for laser engraving is preferably from 0.0005 mm to 10 mm, more preferably from 0.005 mm to 7 mm.

As a combination of a plurality of layers, for example, a layer that can be engraved using a laser having an oscillation wavelength in the near infrared region such as a YAG laser, a fiber laser, or a semiconductor laser is formed on the outermost surface, and the layer below the layer is formed. It is also possible to form a layer capable of laser engraving using an infrared laser such as a carbon dioxide laser or a visible / ultraviolet laser. When laser engraving is performed in this way, engraving can be performed using separate laser engraving equipment equipped with infrared laser and near infrared laser, and laser engraving equipment equipped with both infrared laser and near infrared laser can be used. It is also possible to use.

<Crosslinking process>
The method for producing a relief printing plate precursor for laser engraving of the present invention may be a production method including a crosslinking step for obtaining a relief printing plate precursor having a crosslinked relief forming layer obtained by crosslinking the relief forming layer with heat and / or light. Preferably, the production method includes a crosslinking step for obtaining a relief printing plate precursor having a crosslinked relief-forming layer obtained by crosslinking the relief-forming layer with heat.
The relief forming layer can be crosslinked by heating the relief printing plate precursor for laser engraving (thermal crosslinking step). Examples of the heating means for crosslinking by heat 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 a heated roll for a predetermined time.
By thermally crosslinking the relief forming layer, there is an advantage that, firstly, the relief formed after laser engraving becomes sharp, and secondly, the adhesiveness of engraving residue generated during laser engraving is suppressed.

Moreover, in order to form a bridge | crosslinking by polymerizing a polymeric compound using a photoinitiator etc., you may further perform bridge | crosslinking by light.
When the relief-forming layer contains a photopolymerization initiator, the relief-forming layer is crosslinked by irradiating the relief-forming layer with light that triggers the photopolymerization initiator (also referred to as “active light”). Can do.
The irradiation with actinic light is generally performed on the entire surface of the relief forming layer. Examples of actinic rays include visible light, ultraviolet light, and electron beam, but ultraviolet light is the most common. If the substrate side for immobilizing the relief forming layer, such as the support of the relief forming layer, is the back side, the surface may only be irradiated with light, but the support should be a transparent film that transmits actinic rays. For example, it is preferable to irradiate light from the back side. 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, actinic rays may be irradiated after the relief forming layer is covered with a vinyl chloride sheet and evacuated.

<Other layers>
In the present invention, a cushion layer made of a resin or rubber having cushioning properties may be formed between the support and the resin film (a layer other than the photosensitive layer) or between the resin film and the relief forming resin layer. it can. When a cushion layer is formed between the support and the resin film, a method in which a cushion layer having an adhesive layer on one side is attached with the adhesive layer side facing the cylindrical support is simple. After the cushion layer is applied, the surface can be cut and polished for shaping. A simpler method is a method in which a liquid relief-forming resin composition is applied on a support with a constant thickness and cured with light to form a cushion layer. In order to have cushioning properties, the hardness of the photocured cured product is preferably low. Moreover, you may contain a bubble in the relief forming resin hardened | cured material layer which has this cushioning property. Furthermore, it is possible to shape the surface of the cushion layer by cutting, polishing, etc., and the cushion layer produced in this way is useful as a seamless cushion layer.

(Relief printing plate and plate making method)
The plate making method of the relief printing plate of the present invention comprises a layer forming step of forming a relief forming layer comprising the resin composition for laser engraving of the present invention, and crosslinking the relief forming layer with heat and / or light to form a crosslinked relief forming layer. It is preferable to include a crosslinking step for obtaining the relief printing plate precursor having the above and a engraving step for laser engraving the relief printing plate precursor having the crosslinked relief forming layer. The relief printing plate of the present invention is a relief printing plate having a relief layer obtained by crosslinking and laser engraving a layer made of the resin composition for laser engraving of the present invention. It is preferably a relief printing plate that has been made.
The layer forming step and the cross-linking step in the plate making method of the relief printing plate of the present invention are synonymous with the layer forming step and the cross-linking step in the method for producing a relief printing plate precursor for laser engraving, and the preferred range is also the same.

<Conditions for laser engraving>
In laser engraving, a relief image is created on an original by operating a laser device using a computer as an image to be formed as digital data.
Any laser can be used for the laser engraving as long as the original plate includes a wavelength having absorption. However, in order to perform engraving at a high speed, a laser with a high output is desirable. A laser having an oscillation wavelength in the infrared or near-infrared region, such as a YAG laser, a semiconductor laser, or a fiber laser, is preferable. In addition, an ultraviolet laser having an oscillation wavelength in the ultraviolet region, such as an excimer laser, a YAG laser wavelength-converted to the third or fourth harmonic, a copper vapor laser, and the like, can be ablated to cut bonds between organic molecules, Suitable for fine processing. A laser having an extremely high peak output such as a femtosecond laser can also be used. The laser may be continuous irradiation or pulse irradiation.

Laser engraving is performed in an oxygen-containing gas, generally in the presence of air or in an air stream, but can also be performed in carbon dioxide or nitrogen gas. After engraving is finished, the powdery or liquid substance slightly generated on the relief printing plate surface is washed by an appropriate method such as water containing a solvent or a surfactant, or a water-based cleaning agent is irradiated by a high-pressure spray or the like. Further, it may have a cleaning step (rinsing step) for removing using a method of irradiating high-pressure steam.

The relief printing plate precursor or relief printing plate for laser engraving of the present invention includes a relief image for a printing plate, a stamp / stamp, a design roll for embossing, an insulator, a resistor, and a conductor paste used for electronic component creation. Relief images for patterning, relief images for mold products of ceramics products, relief images for displays such as advertisements and display boards, and prototypes and mother dies of various molded products can be applied and used.

<Surface treatment after laser engraving>
Further, by forming a modified layer on the relief surface of the cylindrical printing plate on which the uneven pattern of the present invention is formed, tackiness on the printing plate surface can be reduced and ink wettability can be improved. Examples of the modified layer include a film treated with a compound that reacts with a surface hydroxyl group such as a silane coupling agent or a titanium coupling agent, or a polymer film containing porous inorganic particles. A widely used silane coupling agent is a compound having in its molecule a functional group highly reactive with the surface hydroxyl group of the substrate. Examples of such a functional group include a trimethoxysilyl group and a triethoxysilyl group. Group, trichlorosilyl group, diethoxysilyl group, dimethoxysilyl group, dichlorosilyl group, monoethoxysilyl group, monomethoxysilyl group and monochlorosilyl group. Further, at least one of these functional groups exists in the molecule, and is immobilized on the surface of the base material by reacting with the surface hydroxyl group of the base material. Further, the compound constituting the silane coupling agent is at least selected from acryloyl group, methacryloyl group, active hydrogen-containing amino group, epoxy group, vinyl group, perfluoroalkyl group, and mercapto group as reactive functional groups in the molecule. Those having one functional group or those having a long-chain alkyl group can be used. When the coupling agent molecule immobilized on the surface has a polymerizable reactive group in particular, it is possible to obtain a stronger coating by irradiating light, heat, or an electron beam and crosslinking after immobilization on the surface. .

The surface treatment liquid is prepared by diluting the above coupling agent with water-alcohol or acetic acid water-alcohol mixed liquid as necessary. The concentration of the coupling agent in the treatment liquid is preferably 0.05% by mass or more and 10.0% by mass or less.

The coupling agent treatment method will be described. The treatment liquid containing the above coupling agent is applied to the printing plate precursor or the surface of the printing plate after laser engraving. The method for applying the coupling agent treatment liquid is not particularly limited, and for example, an immersion method, a spray method, a roll coating method, or a brush coating method can be applied. The coating treatment temperature and the coating treatment time are not particularly limited, but are preferably 5 ° C. or more and 60 ° C. or less, and the treatment time is preferably 0.1 seconds or more and 60 seconds or less. Furthermore, it is preferable to dry the treatment liquid layer on the surface of the resin plate under heating.

Before treating the printing plate surface with a coupling agent, a method of irradiating light in a vacuum ultraviolet region with a wavelength of 200 nm or less, such as a xenon excimer lamp, or by exposing it to a high energy atmosphere such as plasma, a hydroxyl group on the printing plate surface. And the coupling agent can be immobilized at a high density.

In addition, when the layer containing inorganic porous particles is exposed on the printing plate surface, it is treated in a high-energy atmosphere such as plasma, and the organic layer on the surface is slightly etched away to remove minute particles on the printing plate surface. Unevenness can be formed. The effect of improving the ink wettability can be expected by reducing the tack of the printing plate surface by this treatment and making the inorganic porous particles exposed on the surface easy to absorb the ink.

In the method for making a relief printing plate of the present invention, following the engraving step, the following rinsing step, drying step, and / or post-crosslinking step may be included as necessary.
Rinsing step: a step of rinsing the engraved surface of the relief layer surface after engraving with water or a liquid containing water as a main component.
Drying step: a step of drying the engraved relief layer.
Post-crosslinking step: a step of imparting energy to the relief layer after engraving and further crosslinking the relief layer.
Since the engraving residue is attached to the engraving surface after the engraving step, a rinsing step 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, there is a method of washing with tap water, a method of spraying high-pressure water, and a known batch type or conveying type brush type washing machine as a photosensitive resin relief printing machine. For example, when the engraving residue cannot be removed, a rinsing liquid to which soap or a surfactant is added may be used.
When the rinsing process for rinsing the engraving surface is performed, it is preferable to add a drying process for drying the engraved relief forming layer and volatilizing the rinsing liquid.
Furthermore, you may add the post-crosslinking process which further bridge | crosslinks a relief forming layer as needed. By performing the post-crosslinking step, which is an additional cross-linking step, the relief formed by engraving can be further strengthened.

The pH of the rinsing solution that can be used in the present invention is preferably 9 or more, more preferably 10 or more, and still more preferably 11 or more. The pH of the rinsing liquid is preferably 14 or less, more preferably 13.5 or less, still more preferably 13.2 or less, and particularly preferably 12.5 or less. Handling is easy in the said range.
What is necessary is just to adjust pH using an acid and / or a base suitably in order to make a rinse liquid into said pH range, and the acid and base to be used are not specifically limited.
The rinsing liquid that can be used in the present invention preferably contains water as a main component.
Moreover, the rinse liquid may contain water miscible solvents, such as alcohol, acetone, tetrahydrofuran, etc. as solvents other than water.

It is preferable that the rinse liquid contains a surfactant.
As the surfactant that can be used in the present invention, a carboxybetaine compound, a sulfobetaine compound, a phosphobetaine compound, an amine oxide compound, or from the viewpoint of reducing engraving residue removal and influence on the relief printing plate, Preferred are betaine compounds (amphoteric surfactants) such as phosphine oxide compounds.

Examples of the surfactant include known anionic surfactants, cationic surfactants, and nonionic surfactants. Furthermore, fluorine-based and silicone-based nonionic surfactants can be used in the same manner.
Surfactant may be used individually by 1 type, or may use 2 or more types together.
The amount of the surfactant used is not particularly limited, but is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass with respect to the total mass of the rinse liquid.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
In addition, “parts” and “%” of the addition amounts in the examples represent “parts by mass” and “% by mass” unless otherwise specified.

The compounds of Component A to Component F used in Examples and Comparative Examples are shown below.
(Component A)
A-1: Urethane acrylate polymer (UV3630B, manufactured by Nippon Synthetic Chemical Co., Ltd., Mw = 49,500, SP value = 8.1, water-like shape at 20 ° C., 60 ° C. viscosity: 148,000 mPa · s, Tg: 20 Less than ℃)
A-2: Synthesis example is described below (Mw = 42,000, SP value = 7.8, water-like at 20 ° C., viscosity at 60 ° C .: 111,000 mPa · s, Tg: less than 20 ° C.)
A-3: Acrylate polymer (BAC-45, manufactured by Osaka Organic Chemical Industry Co., Ltd., Mw = 3,000, SP value = 8.1, oily at 20 ° C., 60 ° C. viscosity: 60 mPa · s, Tg: 20 Less than ℃)
A-4: The following polymer (Mw = 18,000, SP value = 9.3, water-like at 20 ° C., 60 ° C. viscosity: 54,000 mPa · s, Tg: less than 20 ° C.)
A-5: The following polymer (Mw = 21,000, SP value = 8.7, candy-like at 20 ° C., 60 ° C. viscosity: 65,000 mPa · s, Tg: less than 20 ° C.)
A-6 (for comparison): The following polymer (Mw = 21,000, SP value = 6.8, water-like at 20 ° C., 60 ° C. viscosity: 45,000 mPa · s, Tg: less than 20 ° C.)
A-7 (for comparison): Urethane acrylate polymer (UV3000B, manufactured by Nippon Synthetic Chemical Co., Ltd., Mw = 15,000, SP value = 9.7, water-like at 20 ° C., 60 ° C. viscosity: 52,000 mPa · s , Tg: less than 20 ° C.)
A-8 (for comparison): Styrene butadiene thermoplastic elastomer (manufactured by JSR Corporation, TR2000, SP value = 8.5, non-plastomer at 20 ° C.)
The viscosity at 60 ° C. was measured using a rotational viscometer (Smart H) manufactured by Biscotic Co., Ltd. at a rotation speed of 100 rpm.
Further, Tg was measured using a thermal analysis DSC differential scanning calorimeter (Q1000 type) manufactured by TA Instrument Japan Co., Ltd. under a temperature rising rate of 10 ° C./min.

<Synthesis example of A-2>
In a three-necked flask, 6 parts by mass of isophorone diisocyanate, 100 parts by mass of GI-3000 (manufactured by Nippon Soda Co., Ltd., hydroxylated hydrogenated polybutadiene, Mn = 3,000), KF-6001 (modified at both ends carbinol) After adding 5 parts by mass of silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.3 parts by mass of dibutyltin laurate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) Stir. Thereafter, 1.3 parts by mass of 2-acryloyloxyethyl isocyanate (manufactured by Showa Denko KK, Karenz AOI) was added and further stirred at 60 ° C. for 3 hours to synthesize A-2. The weight average molecular weight Mw was 42,000.

<Synthesis example of A-4>
In a separable flask equipped with a thermometer and a stirrer, 60 parts by mass of 1,8-octanediol (manufactured by Tokyo Chemical Industry Co., Ltd.), 45 parts by mass of adipic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), p-methoxy Polyester having 0.1 parts by weight of phenol (manufactured by Tokyo Chemical Industry Co., Ltd.) in a nitrogen atmosphere at normal pressure and 230 ° C. for 4 hours and then further reacted for 4 hours under reduced pressure of 100 mmHg, and having a hydroxyl group at the terminal (Weight average molecular weight 2,000) was obtained.
56 parts by mass of this polyester, 3.4 parts by mass of isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.06 parts by mass of 2,6-di-tert-butyl-4-methylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) Parts were mixed and reacted at 80 ° C. for 4 hours, and then 4.3 parts by mass of 2-hydroxyethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) and dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) 0 A02 was obtained by adding 0.02 parts by mass and further reacting at 80 ° C. for 2 hours. The weight average molecular weight Mw was 18,000.

<Synthesis example of A-5>
In a separable flask equipped with a thermometer and a stirrer, 60 parts by mass of 1,8-octanediol (manufactured by Tokyo Chemical Industry Co., Ltd.), 45 parts by mass of adipic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), p-methoxy Polyester having 0.1 parts by weight of phenol (manufactured by Tokyo Chemical Industry Co., Ltd.) in a nitrogen atmosphere at normal pressure and 230 ° C. for 4 hours and then further reacted for 4 hours under reduced pressure of 100 mmHg, and having a hydroxyl group at the terminal (Weight average molecular weight 2,000) was obtained.
22 parts by mass of this polyester, 11 parts by mass of carbinol-modified silicone oil (KF-6001, manufactured by Shin-Etsu Chemical Co., Ltd.), 3.4 parts by mass of isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 2,6- 0.06 part by mass of di-tert-butyl-4-methylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) was mixed and reacted at 80 ° C. for 4 hours, and then the reaction product was mixed with 2-hydroxyethyl acrylate (Tokyo Chemical Industry ( A-5 was obtained by adding 4.3 parts by mass) and 0.02 parts by mass of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) and further reacting at 80 ° C. for 2 hours. The weight average molecular weight Mw was 21,000.

<Synthesis example of A-6>
1H, 1H, 2H, 2H-perfluorooctylmethyldimethoxysilane (manufactured by Amax Co.) was added to 70 parts by mass of 1,8-diazabicyclo [5.4.0] undec-7-ene (Wako Pure Chemical Industries, Ltd. )) 0.5 parts by mass and 30 parts by mass of water were added, heated at 70 ° C. for 1 hour, then heated at 110 ° C. for 8 hours while draining water, and a polysiloxane diol having a hydroxyl group at the terminal (weight average molecular weight) 1,830).
To 50 parts by mass of this diol, 3.5 parts by mass of ethylene carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.5 parts by mass of tetraethylammonium iodide (manufactured by Tokyo Chemical Industry Co., Ltd.) are added. Heated for hours. To this, 3.2 parts by mass of isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.05 part by mass of 2,6-di-tert-butyl-4-methylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) were added 80 parts by mass. The mixture was allowed to mix and react at 6 ° C. for 6 hours, and then 4.3 parts by mass of 2-hydroxyethyl acrylate (Tokyo Chemical Industry Co., Ltd.) and 0.02 mass of dibutyltin dilaurate (Tokyo Chemical Industry Co., Ltd.) were added to the reaction product. A-6 was further added and reacted at 80 ° C. for 2 hours to obtain A-6. The weight average molecular weight Mw was 21,000.

(Component B)
B-1: Calcoal 6098 (Kao Co., Ltd., cetanol)
B-2: Calcoal 8098 (manufactured by Kao Corporation, stearyl alcohol)
B-3: Emanon 3201M-V (manufactured by Kao Corporation, ethylene glycol distearate)
B-4: Oleic acid (manufactured by Tokyo Chemical Industry Co., Ltd.)
B-5: Stearylamine (manufactured by Tokyo Chemical Industry Co., Ltd.)
B-6 (for comparison): Decanol (manufactured by Tokyo Chemical Industry Co., Ltd.)

(Component C)
1,6-hexanediol diacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.)
(Component D)
Perbutyl Z (t-butyl peroxybenzoate, manufactured by NOF Corporation)
(Component E)
Carbon Black Asahi # 80 N-220 (Asahi Carbon Co., Ltd., average particle size 20 nm, specific surface area 115 m ² / g, DBP oil absorption 113 ml / 100 g)
(Component F)
KBE-3026 (Shin-Etsu Chemical Co., Ltd., 1,2-bis (triethoxysilyl) ethane)
KBM802 (Shin-Etsu Chemical Co., Ltd., 3-mercaptopropylmethyldimethoxysilane)
(Component G)
1,8-diazabicyclo [5.4.0] undec-7-ene (manufactured by Wako Pure Chemical Industries, Ltd.)

(Examples 1 to 19 and Comparative Examples 1 to 14)
<Method for producing resin composition for laser engraving>
100 parts by mass of component A shown in Table 1 was added to a three-necked flask equipped with a stirring spatula and a cooling tube, 50 parts by mass of tetrahydrofuran was added as a solvent, and the mixture was heated at 70 ° C. for 120 minutes with stirring to dissolve component A. . In this component A dispersion, (Component C) 28 parts by mass of 1,6-hexanediol diacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerizable compound, (Component D) perbutyl Z (t- Butyl peroxybenzoate) (manufactured by NOF Corporation) is added in an amount of 0.005 parts by mass and component B described in Table 1 below is added, and (component E) carbon black Asahi # 80 as a photothermal conversion agent 10 parts by mass of N-220 (Asahi Carbon Co., Ltd.), 10 parts by mass of KBE-3026 as component F, 3 parts by mass of KBM802 (manufactured by Shin-Etsu Chemical Co., Ltd., 3-mercaptopropylmethyldimethoxysilane), (Component G) 0.5 parts by mass of 1,8-diazabicyclo [5.4.0] undec-7-ene (manufactured by Wako Pure Chemical Industries, Ltd.) as an alcohol exchange reaction catalyst was added and stirred to increase viscosity. A resin composition for laser engraving with high consistency was obtained.
When “None” is described in the table, a resin composition for laser engraving was prepared in the same manner except that the component was not added. In addition, when component F was not added, component G was not added.

(Comparative Example 15)
<Method for producing resin composition for laser engraving>
Except for not containing Component C, resin compositions for laser engraving were obtained in the same manner as in Examples 1 to 19 and Comparative Examples 1 to 14.

(Comparative Example 16)
<Method for producing resin composition for laser engraving>
Except not containing Component D, resin compositions for laser engraving were obtained in the same manner as in Examples 1 to 19 and Comparative Examples 1 to 14.

(Comparative Example 17)
<Method for producing resin composition for laser engraving>
Except not containing Component B, resin compositions for laser engraving were obtained in the same manner as in Examples 1 to 19 and Comparative Examples 1 to 14.

<Preparation of flexographic printing plate precursor for laser engraving>
The obtained resin composition for laser engraving was gently cast so as not to flow out onto the PET substrate. It was heated in an oven at 120 ° C. for 5 hours to provide a relief forming layer having a thickness of about 1 mm, and a relief printing plate precursor for laser engraving was prepared. Comparative Example 16 was high in fluidity and did not form a film state.

<Preparation of flexographic printing plate>
The relief forming layer after crosslinking was engraved with the following two types of lasers.
As a carbon dioxide laser engraving machine, engraving by laser irradiation was performed using a high-quality CO ₂ laser marker ML-9100 series (manufactured by Keyence Corporation). After removing the protective film from the printing plate precursor 1 for laser engraving, a carbon dioxide laser engraving machine is used to raster engrave a 1 cm square solid part under the conditions of output: 12 W, head speed: 200 mm / sec, pitch setting: 2,400 DPI did.
As a semiconductor laser engraving machine, a laser recording apparatus equipped with a fiber-coupled semiconductor laser (FC-LD) SDL-6390 (JDSU, wavelength 915 nm) having a maximum output of 8.0 W was used. A 1 cm square solid part was raster engraved with a semiconductor laser engraving machine under conditions of laser output: 7.5 W, head speed: 409 mm / second, pitch setting: 2,400 DPI.

(Evaluation)
<Measurement of film thickness variation>
Regarding the prepared plate, a sample cut to 5 cm × 5 cm is placed on a 100 μm-thick PET film, randomly selected at 10 locations, and the film thickness is measured using a constant-pressure caliper (NTD25-20CX, manufactured by Mitutoyo Corporation). did. Table 1 shows the absolute value of the difference between the measured average value of 10 locations and the value most deviated from the average value. The smaller the value, the higher the film thickness uniformity, and the better the handleability when attaching the printing plate to the printing press.
A film thickness variation of 50 μm or less is acceptable.

<Rinsability measurement>
For engraving, a carbon dioxide laser engraving machine HELIOS 6010 (manufactured by Stock Prints) was used. The engraving conditions were as follows: raster engraving of a 1 cm square solid part under the conditions of engraving conditions: output: 12 W, head speed: 200 mm / second, pitch setting: 2,400 DPI.
The sample immediately after laser engraving was washed with tap water at a constant flow rate for 1 minute without physically rubbing the surface of the engraving surface. By observing with a scanning electron microscope (JSM-7401 manufactured by JEOL Ltd.), the presence or absence of residue remaining on the engraving portion was examined.
A: The engraving residue was powdery and gave a clear uneven pattern.
B: The engraving residue was a highly viscous paste and gave a clear uneven pattern.
C: It can be discriminated that the engraving residue is a pasty paste having a high viscosity and an uneven pattern.
D: It can be determined that the engraving residue is a paste with a low viscosity and is an uneven pattern.
E: The engraving residue is liquid and does not have a clear uneven pattern.
A to C are acceptable levels.

<Insolubilization rate (solvent resistance)>
The solvent resistance was evaluated by looking at the insolubilization rate in propylene glycol monomethyl ether acetate (PGMEA). The insolubilization rate is represented by the following formula.
Insolubilization rate = (mass of plate dried after immersion in PGMEA) / (mass of plate before immersion in PGMEA) × 100
Specifically, a 2 cm × 2 cm sample whose mass was measured was immersed in 100% PGMEA for 24 hours at room temperature, and the taken out plate was dried at 100 ° C. for 3 hours, and then mass measurement was performed. The results are shown in Table 1. The higher the insolubilization rate, the better the solvent resistance.
An insolubilization rate of 80% or more is an acceptable level, and an insolubilization rate of 85% or more is more preferable.

From the results in Table 1, the range of SP value of the binder polymer is 7.0 or more and 9.6 or less, and the larger the number of carbons in the hydrophobic part per molecule of the thickener, the more rinsability and film It was found that the thickness variation and the insolubilization rate all improved. As for the content of component B, when the content is small (Comparative Example 13), the thickening effect does not sufficiently appear and the variation in film thickness is increased. It is thought that the rinsing property was lowered by the reduction. On the other hand, when there was too much content of the component B (comparative example 12), there existed a tendency for the film thickness variation to rise for excessive viscosity increase, and the insolubilization rate fell.
From the above results, by preparing a flexographic printing plate precursor containing component A to component D within the range specified in the present invention, the film thickness uniformity, engraving residue rinsing property, and solvent ink resistance are excellent. We were able to provide a flexographic printing plate precursor.

Claims

(Component A) a binder polymer having an SP value of 7.0 or more and 9.6 or less and a plastomer at 20 ° C.,
(Component B) a compound having a hydrophobic site,
(Component C) a polymerizable compound, and
(Component D) contains a thermal polymerization initiator,
The hydrophobic part of component B is a hydrocarbon group having 15 or more carbon atoms,
A resin composition for laser engraving, wherein the content (mass) of component B / content (mass) of component A is 0.01 to 0.5.
The resin composition for laser engraving according to claim 1, wherein Component A is polyurethane acrylate.
The resin composition for laser engraving according to claim 1 or 2, wherein Component A has a polar group.
The resin composition for laser engraving according to any one of claims 1 to 3, wherein Component B has a polar group.
The resin composition for laser engraving according to any one of claims 1 to 4, wherein Component B has at least one selected from the group consisting of an ester bond, a carboxy group, and a hydroxy group.
6. The resin composition for laser engraving according to claim 1, further comprising (Component E) a photothermal conversion agent.
The resin composition for laser engraving according to claim 6, wherein Component E is carbon black.
The resin composition for laser engraving according to claim 1, further comprising (Component F) a compound having at least one of a hydrolyzable silyl group and a silanol group.
A relief printing plate precursor for laser engraving, comprising a crosslinked relief forming layer obtained by crosslinking the relief forming layer comprising the resin composition for laser engraving according to any one of claims 1 to 8 with light and / or heat.
A layer forming step of forming a relief forming layer comprising the resin composition for laser engraving according to any one of claims 1 to 8, and
A method for producing a relief printing plate precursor for laser engraving, comprising a crosslinking step of crosslinking the relief forming layer with light and / or heat to obtain a relief printing plate precursor having a crosslinked relief forming layer.
A step of obtaining a relief printing plate precursor for laser engraving having a crosslinked relief forming layer obtained by crosslinking the relief forming layer comprising the resin composition for laser engraving according to any one of claims 1 to 8 with light and / or heat; And
A method for making a relief printing plate, comprising: engraving a relief printing plate precursor having the crosslinked relief forming layer by laser engraving to form a relief layer.
The method for making a relief printing plate according to claim 11, wherein the laser engraving is performed by a semiconductor laser.
A method for making a relief printing plate, comprising the steps of: preparing a relief printing plate precursor for laser engraving according to claim 9; and engraving a step of laser engraving the crosslinked relief forming layer to form a relief forming layer.
A relief printing plate having a relief layer produced by the plate making method of a relief printing plate according to any one of claims 11 to 13.
Use of the resin composition for laser engraving according to any one of claims 1 to 8 in a relief forming layer of a relief printing plate precursor for laser engraving.