JP2012153121A - Resin composition for laser engraving, method for producing the same, relief printing original plate for laser engraving, method for manufacturing the same, relief printing plate, and method for making the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for laser engraving which is excellent in engraving residue removing property and film strength and forms a highly delicate image, a relief printing original plate using the composition, a method for making a relief printing plate using the original plate, and a relief printing plate obtained by the method.SOLUTION: The resin composition for laser engraving includes: (component A) a main polymer; (component B) a dispersion polymer smaller in weight-average molecular weight than the main polymer; and (component C) a filler, the component C being preliminarily dispersed in the component B. The relief printing original plate using the composition, a method for making a relief printing plate using the original plate, and a relief printing plate obtained by the method are also provided.

Description

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

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 original is directly irradiated with a laser, and thermal decomposition and volatilization are caused by photothermal conversion to form a recess. 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. In general, a high-power carbon dioxide laser is used as a laser for this method. In the case of a carbon dioxide laser, all organic compounds can absorb irradiation energy and convert it into heat. On the other hand, inexpensive and small-sized semiconductor lasers have been developed. However, since these are visible and near infrared light, it is necessary to absorb the laser light and convert it into heat.
On the other hand, Patent Literature 1 and Patent Literature 2 are known as photosensitive resin compositions used as resists.

JP 2003-26950 A JP 2008-81732 A

  An object of the present invention is to provide a resin composition for laser engraving, which is excellent in engraving residue removal and film strength, and provides a high-definition image, a relief printing plate precursor using the resin composition for laser engraving, and using the same It is to provide a method for making a relief printing plate and a relief printing plate obtained thereby.

The above-described problems of the present invention have been solved by means described in the following <1>, <12> to <16>, and <19>. It is described below together with <2> to <11>, <17> and <18> which are preferred embodiments.
<1> Contains (Component A) main polymer, (Component B) a dispersion polymer having a weight average molecular weight smaller than that of the main polymer, and (Component C) filler, and Component C is dispersed in advance by Component B. A resin composition for laser engraving,
<2> The resin composition for laser engraving according to <1>, wherein the weight average molecular weight of component A is 5,000 to 300,000,
<3> The resin composition for laser engraving according to <1> or <2>, wherein the component A and the component B are the same type of polymer,
<4> The resin composition for laser engraving according to any one of the above <1> to <3>, wherein the weight average molecular weight of component B is half or less of the weight average molecular weight of component A,
<5> The resin composition for laser engraving according to any one of the above <1> to <4>, wherein both component A and component B are polyvinyl butyral,
<6> The resin composition for laser engraving according to the above <5>, wherein the difference between the absolute values of mol% of hydroxyl groups of component A and component B is 0 to 10,
<7> The resin composition for laser engraving according to any one of the above <1> to <6>, wherein Component C is carbon black,
<8> (Component D) The resin composition for laser engraving according to any one of the above <1> to <7>, further comprising an ethylenically unsaturated compound,
<9> (Component E) The resin composition for laser engraving according to any one of the above <1> to <8>, further comprising a polymerization initiator,
<10> (Component F) The resin composition for laser engraving according to any one of the above <1> to <9>, further comprising a plasticizer,
<11> (Component G) The laser engraving according to any one of <1> to <10>, further including at least one oxy compound of a metal or metalloid selected from Group 1 to 16 of the periodic table. Resin composition,
<12> In any one of the above items <1> to <11>, including a dispersion step of dispersing component C in advance with component B, and a mixing step of mixing the dispersion prepared in the dispersion step and component A A method for producing the resin composition for laser engraving,
<13> A relief printing plate precursor for laser engraving having a relief forming layer comprising the resin composition for laser engraving according to any one of <1> to <11> above,
<14> A relief printing plate precursor for laser engraving having a crosslinked relief forming layer obtained by thermally crosslinking a relief forming layer comprising the resin composition for laser engraving according to any one of <1> to <11> above,
<15> A layer forming step of forming a relief forming layer comprising the resin composition for laser engraving according to any one of the above <1> to <11>, and the relief forming layer by light and / or heat A method for producing a relief printing plate precursor for laser engraving, comprising a crosslinking step of obtaining a relief printing plate precursor that is crosslinked and has a crosslinked relief-forming layer,
<16> A layer forming step of forming a relief forming layer comprising the resin composition for laser engraving according to any one of the above <1> to <11>, the relief forming layer is crosslinked by light and / or heat. A method for making a relief printing plate comprising a crosslinking step for obtaining a relief printing plate precursor having a crosslinked relief forming layer, and a engraving step for laser engraving the relief printing plate precursor having the crosslinked relief forming layer to form a relief layer,
<17> The method for making a relief printing plate according to <16>, wherein the laser engraving is performed with a laser having a wavelength of 700 to 1,300 nm,
<18> The process for making a relief printing plate according to <16> or <17>, further comprising a washing step of washing the relief layer surface after engraving with water or an aqueous solution,
<19> A relief printing plate having a relief layer produced by the method for making a relief printing plate according to any one of <16> to <18>.

  According to the present invention, the resin composition for laser engraving, which is excellent in engraving residue removal property and film strength and provides a high-definition image, the relief printing plate precursor using the laser engraving resin composition, and the same A method for making a relief printing plate and a relief printing plate obtained thereby were provided.

It is a schematic block diagram (perspective view) which shows the plate making apparatus provided with the semiconductor laser recording device with a fiber used for this invention.

Hereinafter, the present invention will be described in detail.
In the present invention, the description of “lower limit to upper limit” representing a 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. Further, “(component A) main polymer” or the like is also simply referred to as “component A” or the like.

(Resin composition for laser engraving)
The resin composition for laser engraving of the present invention (hereinafter also simply referred to as “resin composition”) includes (Component A) a main polymer, (Component B) a dispersion polymer having a weight average molecular weight smaller than that of the main polymer, and (Component C) A filler is contained, and Component C is dispersed in advance by Component B.
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 explanation 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) main polymer>
The resin composition for laser engraving of the present invention contains (Component A) a main polymer.
The main polymer is a binder polymer (hereinafter also referred to as “binder”) contained in the resin composition for laser engraving, and is a binder resin having a molecular weight of 1,000 to 1,000,000. The binder of this invention can be used individually by 1 type, or can use 2 or more types together. In particular, when the resin composition for laser engraving is used for the relief forming layer of the printing plate precursor, the binder of the present invention is selected in consideration of various performances such as laser engraving sensitivity, ink acceptability, and engraving residue dispersibility. It is preferable to do.
The weight average molecular weight of the main polymer of the present invention is preferably 5,000 to 500,000, more preferably 5,000 to 300,000, and particularly preferably 10,000 to 200,000. The weight average molecular weight is a value in terms of polystyrene as measured by GPC.
As the main polymer of the present invention, polystyrene resin, polyester resin, polyamide resin, polyurea resin, polyamideimide resin, polyurethane resin, polysulfone resin, polyethersulfone resin, polyimide resin, polycarbonate resin, hydrophilic polymer containing hydroxyethylene units, Examples include acrylic resin, acetal resin, epoxy resin, polycarbonate resin, rubber, and thermoplastic elastomer. Preferably, an acetal resin is used.

  As the main polymer of the present invention, known compounds synthesized by various polymerization reactions such as addition polymerization and polycondensation can be used, and a polymer suitable for the purpose can also be selected. For example, from the viewpoint of laser engraving sensitivity, a polymer containing a partial structure that is thermally decomposed by exposure or heating is preferable. For example, when the purpose is to form a soft and flexible film, a soft resin or a thermoplastic elastomer is selected. Furthermore, if the resin composition for laser engraving is applied to the relief forming layer in the relief printing plate precursor for laser engraving, the ease of preparation of the composition for the relief forming layer and the oil-based ink in the resulting relief printing plate It is preferable to use a hydrophilic or alcoholic polymer from the viewpoint of improving the resistance to water.

In addition, when the relief forming layer is cured by heating or exposure and used for the purpose of improving the strength, reactive functional groups such as hydroxyl group, alkoxy group, hydrolyzable silyl group and silanol group are present in the molecule. It is preferable that the main polymer has
These functional groups may be present anywhere in the main polymer molecule, but are preferably present in the side chain of the main polymer chain. Examples of such polymers include vinyl copolymers (copolymers of vinyl monomers such as polyvinyl alcohol and polyvinyl acetal and derivatives thereof), acrylic resins (copolymers of acrylic monomers such as hydroxyethyl (meth) acrylate), and the like. Derivatives) are preferably used. Here, the vinyl monomer copolymer derivative is specifically a hydroxyl group of the vinyl alcohol unit or a form in which the α-position of the hydroxyl group is chemically modified to extend the side chain, and a hydroxyl group or a carboxyl group is formed at the terminal. It refers to a polymer into which a functional group has been introduced.
As the main polymer used in the present invention, a binder polymer having a hydroxyl group is particularly preferably used.

[Binder polymer having a hydroxyl group]
Hereinafter, the binder polymer having a hydroxyl group (hereinafter, also referred to as “specific polymer” as appropriate) used as the main polymer of the present invention will be described. This binder polymer is preferably insoluble in water and soluble in an alcohol having 1 to 4 carbon atoms.

  As a specific polymer, polyvinyl butyral (PVB) and its derivatives, an acrylic resin having a hydroxyl group in a side chain, from the viewpoint of having both water-based ink suitability and UV ink suitability and having high engraving sensitivity and good film properties, And the epoxy resin etc. which have a hydroxyl group in a side chain are preferable. Among these, polyvinyl butyral (PVB) and its derivatives are more preferable.

  The specific polymer is particularly preferable because the engraving sensitivity is improved when the glass transition temperature (Tg) is 20 ° C. or higher when combined with a photothermal conversion agent described later. Hereinafter, the binder polymer having such a glass transition temperature is referred to as a non-elastomer. That is, an elastomer is generally defined academically as a polymer having a glass transition temperature of room temperature or lower (see Science Dictionary 2nd Edition, Editor International Science Promotion Foundation, published by Maruzen Co., Ltd., P154). . Therefore, a non-elastomer refers to a polymer having a glass transition temperature exceeding normal temperature. Although there is no restriction | limiting in the upper limit of the glass transition temperature of a binder polymer, it is preferable from a viewpoint of handleability that it is 200 degrees C or less, and it is more preferable that it is 25 degreeC or more and 120 degrees C or less.

When a polymer having a glass transition temperature of room temperature (20 ° C.) or higher is used, the specific polymer takes a glass state at room temperature. Therefore, compared to a rubber state, the thermal molecular motion is considerably suppressed. It is in. In laser engraving, in addition to the heat imparted by the infrared laser during laser irradiation, the heat generated by the function of the photothermal conversion agent used in combination with the desired heat is transferred to a specific polymer around it, which decomposes and dissipates. As a result, engraving is performed to form a recess.
In a preferred embodiment of the present invention, it is considered that heat transfer and thermal decomposition to a specific polymer occur effectively when a photothermal conversion agent is present in a state where thermal molecular motion of the specific polymer is suppressed. It is presumed that the engraving sensitivity is further increased by this effect.
Specific examples of the non-elastomer which is a particularly preferable embodiment of the specific polymer are listed below.

(1) Polyvinyl acetal derivative In this specification, a polyvinyl acetal and its derivative are also only called a polyvinyl acetal derivative hereafter. That is, in this specification, a polyvinyl acetal derivative is used by the concept including polyvinyl acetal and its derivative, and shows the general term of the compound obtained by carrying out the cyclic acetalization of the polyvinyl alcohol obtained by saponifying a polyvinyl acetate.
The acetal content in the polyvinyl acetal derivative is preferably 30 to 90%, more preferably 50 to 85%, assuming that the total number of moles of the raw vinyl acetate monomer is 100%, and the mole percentage of vinyl alcohol units to be acetalized. 55 to 78% is particularly preferable.
The vinyl alcohol unit in the polyvinyl acetal derivative is preferably 10 to 70 mol%, more preferably 15 to 50 mol%, particularly preferably 22 to 45 mol%, based on the total number of moles of the starting vinyl acetate monomer.
Moreover, the polyvinyl acetal derivative may have a vinyl acetate unit as other components, and the content thereof is preferably 0.01 to 20 mol%, and more preferably 0.1 to 10 mol%. The polyvinyl acetal derivative may further have other copolymer units.
Examples of the polyvinyl acetal derivative include a polyvinyl butyral derivative, a polyvinyl propylal derivative, a polyvinyl ethylal derivative, a polyvinyl methylal derivative, etc. Among them, a polyvinyl butyral derivative (hereinafter also referred to as “PVB derivative”) is particularly preferable. In these descriptions, for example, the term “polyvinyl butyral derivative” is used in the present specification to include polyvinyl butyral and its derivatives, and the same applies to other polyvinyl acetal derivatives.

Hereinafter, polyvinyl butyral will be described as a particularly preferable example of polyvinyl acetal. However, the present invention is not limited to this.
An example of the structure of the polyvinyl butyral derivative is as shown below, and each of these structural units is included at an arbitrary ratio, but L is preferably 50 mol% or more.

As the PVB derivative, it is also available as a commercial product, and preferred specific examples thereof include, from the viewpoint of alcohol solubility (particularly ethanol), “S-Lec B” series, “S-LEC K” (manufactured by Sekisui Chemical Co., Ltd.). KS) ”series and“ Denkabutyral ”manufactured by Denki Kagaku Kogyo Co., Ltd. are preferred. From the viewpoint of alcohol solubility (especially ethanol),“ S-Lec B ”series manufactured by Sekisui Chemical Co., Ltd., Denki Kagaku Kogyo Co., Ltd. “Denkabutyral” made by) is more preferable.
Among these, particularly preferred commercial products are shown below together with the values of L, m, and n and the molecular weight in the above formula. In the “S Lec B” series manufactured by Sekisui Chemical Co., Ltd., “BL-1” (L = 61, m = 3, n = 36, weight average molecular weight 190000), “BL-1H” (L = 67, m = 3, n = 30, weight average molecular weight 2 million), “BL-2” (L = 61, m = 3, n = 36, weight average molecular weight about 27,000), “BL− 5 ”(L = 75, m = 4, n = 21, weight average molecular weight 32,000),“ BL-S ”(L = 74, m = 4, n = 22, weight average molecular weight 23,000) "BM-S" (L = 73, m = 5, n = 22, weight average molecular weight 53,000), "BH-S" (L = 73, m = 5, n = 22, weight average molecular weight 6) In addition, “# 3000-1” (L = 71, m = 1, n = 28, weight average molecular weight 74,000) in the “Denkabutyral” series manufactured by Denki Kagaku Kogyo Co., Ltd. “# 3000-2” (L = 71, m = 1, n = 28, weight average molecular weight 90000), “# 3000-4” (L = 71, m = 1, n = 28, weight average molecular weight 17,000), “# 4000-2” (L = 71, m = 1, n = 28, weight average molecular weight 152,000), “# 6000-C” (L = 64, m = 1, n = 35, weight average molecular weight 308,000), "# 6000-EP" (L = 56, m = 15, n = 29, weight average molecular weight 381,000), "# 6000-CS" (L = 74 , M = 1, n = 25, weight average molecular weight 322,000), “# 6000-AS” (L = 73, m = 1, n = 26, weight average molecular weight 242,000) "B60H" (L = 71, m = 1, n = 28, weight average molecular weight 14,000,000), "B6" HH "(L = 80, m = 1, n = 19, weight average molecular weight 190,000)," B30HH "(L = 80, m = 1, n = 19, weight average molecular weight 130,000) may be mentioned, respectively.
When a relief forming layer is formed using a PVB derivative as a specific polymer, a method in which a solution dissolved in a solvent is cast and dried is preferable from the viewpoint of the smoothness of the film surface.

(2) Acrylic resin As the main polymer of the present invention, an acrylic resin having a hydroxyl group is preferably mentioned.
As the acrylic monomer used for the synthesis of the acrylic resin having a hydroxyl group, for example, (meth) acrylic acid esters, crotonic acid esters, (meth) acrylamides having a hydroxyl group in the molecule are preferable. . Specific examples of such a monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like.

Moreover, as an acrylic resin, acrylic monomers other than the acrylic monomer which has the said hydroxyl group can also be included as a copolymerization component. Such (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) ) Acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, acetoxyethyl (meth) acrylate, phenyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2 -Ethoxyethyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, diethylene glycol monomethyl ether (meth) a Relate, diethylene glycol monoethyl ether (meth) acrylate, diethylene glycol monophenyl ether (meth) acrylate, triethylene glycol monomethyl ether (meth) acrylate, triethylene glycol monoethyl ether (meth) acrylate, dipropylene glycol monomethyl ether (meth) acrylate , Polyethylene glycol monomethyl ether (meth) acrylate, polypropylene glycol monomethyl ether (meth) acrylate, monomethyl ether (meth) acrylate of a copolymer of ethylene glycol and propylene glycol, N, N-dimethylaminoethyl (meth) acrylate, N , N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopro Le (meth) acrylate.
Furthermore, a modified acrylic resin comprising an acrylic monomer having a urethane group or a urea group can also be preferably used.
Among these, alkyl (meth) acrylates such as lauryl (meth) acrylate and (meth) acrylates having an aliphatic cyclic structure such as t-butylcyclohexyl methacrylate are particularly preferable from the viewpoint of water-based ink resistance.

Moreover, novolak resin which is resin which condensed phenols and aldehydes on acidic conditions can be used as a specific polymer.
Preferred novolak resins include, for example, novolak resins obtained from phenol and formaldehyde, novolak resins obtained from m-cresol and formaldehyde, novolak resins obtained from p-cresol and formaldehyde, and obtained from o-cresol and formaldehyde. Novolak resin, novolak resin obtained from octylphenol and formaldehyde, novolak resin obtained from m- / p-mixed cresol and formaldehyde, phenol / cresol (m-, p-, o- or m- / p-, m- / No-, o- / p-mixed) and a novolak resin obtained from formaldehyde.

Among the specific polymers, polyvinyl butyral derivatives are particularly preferable from the viewpoints of rinsing properties and printing durability when used as a relief forming layer.
The hydroxyl group content contained in the specific polymer is preferably 0.1 to 15 mmol / g, and more preferably 0.5 to 7 mmol / g, in any of the above-described polymers.

Component A in the resin composition of the present invention may be used alone or in combination of two or more.
The content of Component A contained in the resin composition of the present invention is preferably 10 to 60% by weight, more preferably 15 to 55% by weight, and particularly preferably 20 to 50% by weight with respect to the total solid content.

<(Component B) Dispersion polymer having a weight average molecular weight smaller than that of the main polymer>
The resin composition for laser engraving of the present invention contains (Component B) a dispersion polymer having a weight average molecular weight smaller than that of the main polymer.
(Component B) The dispersion polymer having a weight average molecular weight smaller than that of the main polymer is a dispersion polymer that disperses the (Component C) filler contained in the resin composition for laser engraving of the present invention (hereinafter simply referred to as “dispersion polymer”). Also called.).
It is essential that the weight average molecular weight of the dispersion polymer is smaller than the weight average molecular weight of the main mepolymer, and preferably not more than half.
Component B can be selected from the resin group in which component A is selected. That is, polystyrene resin, polyester resin, polyamide resin, polyurea resin, polyamideimide resin, polyurethane resin, polysulfone resin, polyethersulfone resin, polyimide resin, polycarbonate resin, hydrophilic polymer containing hydroxyethylene units, acrylic resin, acetal resin, Examples thereof include an epoxy resin, a polycarbonate resin, rubber, and a thermoplastic elastomer.
Among them, like the component A, a binder having a reactive functional group such as a hydroxyl group, an alkoxy group, a hydrolyzable silyl group, and a silanol group in the molecule is preferable, and a filler that can easily disperse the filler is preferable. . More preferably, polyvinyl butyral (PVB) and its derivatives, an acrylic resin having a hydroxyl group in the side chain, an epoxy resin having a hydroxyl group in the side chain, and the like are mentioned. Among these, polyvinyl butyral (PVB) and its derivatives are particularly preferable.

As long as the component B has a weight average molecular weight smaller than that of the component A, it may be a different type of polymer from the component A or the same type of polymer. Preferably, they are the same type of polymer, and both component A and component B are polyvinyl butyral (PVB) and its derivatives, an acrylic resin having a hydroxyl group in the side chain, an epoxy resin having a hydroxyl group in the side chain, and the like. It is particularly preferable that both are polyvinyl butyral (PVB) and derivatives thereof. Here, the same type of polymer refers to a polymer having the same repeating unit.
When both component A and component B are polymers having a hydroxyl group such as a polyvinyl butyral derivative, it is preferable that the difference between the absolute values of mol% of the hydroxyl groups contained in the polymer is 0-10.

The absolute value of mol% of the hydroxyl group in the polymer is measured using a ¹ H-NMR spectrum. For example, dry polyvinyl butyral resin powder is dissolved in deuterated dimethyl sulfoxide to form a 1 wt% solution, then a small amount of tetramethylsilane is added as a standard substance, and a ¹ H-NMR spectrum is measured at 25 ° C. It is calculated from the integrated intensity of each peak of the obtained spectrum.

<(Component C) filler>
The (Component C) filler in the present invention is not particularly limited as long as it is not molecularly dispersed in the resin composition but is dispersed in a solid state.
Examples of fillers that can be used in the present invention include organic fillers and inorganic fillers.

Examples of the organic filler include low density polyethylene particles, high density polyethylene particles, polystyrene particles, various organic pigments, microballoons, urea-formalin fillers, polyester particles, cellulose fillers, and organic metals.
Examples of the organic pigment include known pigments, indigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments. Fluorescent pigments, carbon black, etc. can be used. Moreover, you may contain the inorganic pigment.
Among these, carbon black is particularly preferable as the organic filler.

Carbon black is usually used in various applications such as for color, rubber, and dry batteries, as long as there is no problem with dispersion stability in the resin composition constituting the relief forming layer, as well as products with standards classified by ASTM. Any carbon black used can be used.
The carbon black here includes, for example, furnace black, thermal black, channel black, lamp black, acetylene black, and the like.
In the present invention, it is also possible to use carbon black having a relatively low specific surface area and relatively low DBP (Di-butyl phthalate) absorption, and fine carbon black having a large specific surface area.

Examples of suitable carbon black commercial products include Printex U (registered trademark), Printex A (registered trademark) or Specialzwarz 4 (registered trademark) (both manufactured by Degussa), Seast 600 ISAF-LS (Tokai Carbon Co., Ltd.) Asahi # 70 (N-300) (Asahi Carbon Co., Ltd.), Ketjen Black EC600JD (Lion Co., Ltd.) and the like.
For such selection of carbon black, for example, “Carbon Black Handbook” edited by Carbon Black Association can be referred to.
The average primary particle size of carbon black is preferably greater than 20 nm and less than 80 nm, and more preferably greater than 25 nm and less than 70 nm. Within the above range, aggregation can be suppressed and the dispersibility is excellent.

Inorganic fillers include alumina, titania, zirconia, kaolin, calcined kaolin, talc, wax, diatomaceous earth, calcium carbonate, aluminum hydroxide, magnesium hydroxide, zinc oxide, lithopone, amorphous silica, colloidal silica, calcined stone Examples include kou, silica, magnesium carbonate, titanium oxide, alumina, barium carbonate, barium sulfate, and mica.
Among these, silica or alumina is preferable, and silica is particularly preferable.

The shape of the filler that can be used in the present invention is not particularly limited, and examples thereof include a spherical shape, a layer shape, a fiber shape, and a hollow balloon shape. Among these, a spherical shape or a layered shape is preferable, and a spherical shape is more preferable.
The average particle size (average primary particle size) of the filler that can be used in the present invention is preferably 10 nm to 10 μm, more preferably 10 nm to 5 μm, and particularly preferably 50 nm to 3 μm. preferable. Within the above range, the stability of the resin composition is good, and the occurrence of particulate film leakage after engraving can be suppressed, and the image quality is excellent.

Further, as the layered filler, an inorganic layered compound having a thin flat plate shape is preferably exemplified, for example, a mica group such as natural mica and synthetic mica represented by the following formula, 3MgO · 4SiO · H ₂ O Examples include talc, teniolite, montmorillonite, saponite, hectorite, and zirconium phosphate.
A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
(In the formula, A represents any of K, Na, and Ca, B and C represent any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D represents Si or Al). To express.)

  The shape of the inorganic stratiform compound that can be used in the present invention is preferably an aspect ratio of 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is the ratio of the major axis to the thickness of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

As for the particle diameter of the inorganic stratiform compound that can be used in the present invention, the average major axis is preferably 0.3 to 20 μm, more preferably 0.5 to 10 μm, and more preferably 1 to 5 μm. Particularly preferred. The average thickness of the particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.01 μm or less.
For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

Preferred examples of the spherical silica particles that can be used in the present invention include the following commercially available products. In addition, the numerical value in a parenthesis represents an average particle diameter.
As a product of Nippon Aerosil Co., Ltd., AEROSIL RM50 (40 nm), R711 (12 nm), R7200 (12 nm), AEROSIL OX50 (40 nm), 50 (30 nm), 90 G (20 nm), 130 (16 nm), 150 (14 nm), Examples include 200 (12 nm), 200 CF (12 nm), 300 (7 nm), and 380 (7 nm).
Sunsphere H-31 (3 μm), H-51 (5 μm), H-121 (12 μm), H-201 (20 μm), Sunsphere L-31 (3 μm), L-51 (5 μm), Sunsphere NP-30 (4 μm), NP-100 (10 μm), NP-200 (20 μm).
As a product made by Nissan Chemical Industries, Ltd., methanol silica sol (10-20 nm), MA-ST-M (10-20 nm), IPA-ST (10-20 nm), EG-ST (10-20 nm), EG-ST- ZL (70-100 nm), NPC-ST (10-20 nm), DMAC-ST (10-20 nm), MEK-ST (10-20 nm), XBA-ST (10-20 nm), MIBK-ST (10-20 nm) ).

  Examples of mica particles that can be used in the present invention include synthetic mica (“Somasif ME-100” manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1,000 or more).

  The addition amount of (Component C) filler in the resin composition for laser engraving of the present invention is 0.5 to 20% by weight based on the total solid content (excluding the solvent) of the resin composition for laser engraving of the present invention. Is preferable, 1 to 15% by weight is more preferable, and 3 to 10% by weight is particularly preferable. Moreover, when using dispersing agents, such as a polymer, it is preferable that the total amount of a filler and a dispersing agent is in the range of said addition amount.

[Method of dispersing filler by component B]
As a method of dispersing the filler with the component B, a known dispersion technique used for ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, a bead 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 dispersion of component C by component B of the present invention is performed before the dispersion of component B and component C is mixed with component A.
The weight% of component B with respect to the total content of component B and component C is preferably 30 to 80% by weight, more preferably 40 to 70% by weight.
As described above, the content of the dispersion of component B and component C is preferably 1 to 20% by weight based on the total solid content (amount excluding the solvent) of the resin composition for laser engraving of the present invention. 15 weight% is more preferable and 5 to 10 weight% is especially preferable.
As the solvent for dispersion, various known solvents are used, and among them, propylene glycol monomethyl acetate is more preferably used.

<(Component D) ethylenically unsaturated compound>
The resin composition for laser engraving of the present invention can contain (Component D) an ethylenically unsaturated compound.
The ethylenically unsaturated compound that can be used in the present invention can be arbitrarily selected from compounds having at least 1, preferably 2 or more, more preferably 2 to 6 ethylenically unsaturated groups.

Hereinafter, a monofunctional monomer having one ethylenically unsaturated group and a polyfunctional monomer having two or more ethylenically unsaturated groups, which are used as the ethylenically unsaturated compound, will be described.
Monofunctional monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and monohydric alcohol compounds, unsaturated carboxylic acids and monovalent amine compounds And amides. Polyfunctional monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and polyhydric alcohol compounds, unsaturated carboxylic acids and polyvalent monomers. Examples include amides with amine compounds.
In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used.
Since the resin composition of the present invention forms a crosslinked structure in the film, a polyfunctional monomer is preferably used. The molecular weight of the polyfunctional monomer is preferably 200 to 2,000.

Examples of the polyfunctional monomer include esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds.
Specific examples thereof include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, and trimethylol. Propane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylol ethane 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 oligomers and the like.

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

Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bisacrylamide, methylene bismethacrylamide, 1,6-hexamethylene bisacrylamide, 1,6-hexamethylene bismethacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.
Examples of other preferable amide-based polyfunctional ethylenically unsaturated compounds include those having a cyclohexylene structure described in JP-B No. 54-21726.

A urethane-based addition polyfunctional monomer produced by using an addition reaction between an isocyanate and a hydroxyl group is also suitable as a polyfunctional ethylenically unsaturated compound. 2 or more in one molecule in which a polyisocyanate compound having two or more isocyanate groups per molecule described therein and an ethylenically unsaturated compound containing a hydroxyl group represented by the following formula (A) are added And urethane-based polyfunctional ethylenically unsaturated compounds containing ethylenically unsaturated groups.
_{CH 2 = C (R) COOCH} 2 CH (R ') OH (A)
(However, R and R ′ represent H or CH _3. )

Further, urethane acrylates as described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 No. 1, JP-B 62-39417, and JP-B 62-39418, and urethane-based polyfunctional ethylenically unsaturated compounds having an ethylene oxide chain are also suitable.
Furthermore, polyfunctional ethylenically unsaturated compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 By using, a resin composition crosslinked in a short time can be obtained.

  Examples of other polyfunctional ethylenically unsaturated compounds include polyester acrylates and epoxy resins as described in JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490. And polyfunctional acrylates and methacrylates such as epoxy acrylates obtained by reacting (meth) acrylic acid. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, and JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like are also included. Can be mentioned. 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. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

Examples of the ethylenically unsaturated compound that can be used in the present invention include saturated bridged cyclic polyfunctional monomers.
As the saturated bridged cyclic polyfunctional monomer, an alicyclic polyfunctional monomer having a condensed ring structure such as a bicyclo ring having two methacryloyloxy groups or acryloyloxy groups or a compound having a tricyclo ring structure is used. It is preferable from the viewpoint of control.
Examples of the bicyclo ring and tricyclo ring structure include a norbornene skeleton (bicyclo [2.2.1] heptane), a dicyclopentadiene skeleton (tricyclo [5.2.1.0 ^2,6 ] decane), an adamantane skeleton (tricyclo [3 .3.1.1 ^3,7 ] decane) and the like.
As the saturated bridged cyclic polyfunctional monomer, an amino group may be directly bonded to a bicyclo ring or tricyclo ring part, or may be bonded via an aliphatic part such as alkylene such as methylene or ethylene. Good. Furthermore, the hydrogen atom of the alicyclic hydrocarbon group of these condensed ring structures may be substituted with an alkyl group or the like.
In the present invention, the saturated bridged cyclic polyfunctional monomer is preferably an alicyclic polyfunctional monomer selected from the following.

Further, as the ethylenically unsaturated compound, an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group and a monofunctional or polyfunctional alcohol, amine or thiol. Addition reaction products, and further substitution products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a halogeno group or a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols are also suitable. It is.
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.
There is no restriction | limiting in particular as an ethylenically unsaturated compound, A well-known various compound other than the compound illustrated above can be used, For example, the compound of Paragraph 0098-0124 of Unexamined-Japanese-Patent No. 2009-204962, etc. May be used.

In the present invention, a compound having a sulfur atom in the molecule is preferably used as the ethylenically unsaturated compound from the viewpoint of improving engraving sensitivity.
Thus, as an ethylenically unsaturated compound which has a sulfur atom in a molecule | numerator, from a viewpoint of an engraving sensitivity improvement, it has two or more ethylenically unsaturated bonds especially among two ethylenically unsaturated bonds. It is preferable to use a radically polymerizable compound having a carbon-sulfur bond at the site to be linked (hereinafter also referred to as “sulfur-containing polyfunctional monomer” as appropriate).
The functional group containing a carbon-sulfur bond in the sulfur-containing polyfunctional monomer in the present invention includes sulfide, disulfide, sulfoxide, sulfonyl, sulfonamide, thiocarbonyl, thiocarboxylic acid, dithiocarboxylic acid, sulfamic acid, thioamide, and thiocarbamate. , A functional group containing dithiocarbamate or thiourea.
In addition, as a linking group containing a carbon-sulfur bond that connects two ethylenically unsaturated bonds in a sulfur-containing polyfunctional monomer, -C-S-, -C-SS-, -NHC (= S) O A linking group containing at least one unit selected from —, —NHC (═O) S—, —NHC (═S) S—, and —C—SO ₂ — is preferable.

Further, the number of sulfur atoms contained in the molecule of the sulfur-containing polyfunctional monomer is not particularly limited as long as it is 1 or more, and can be appropriately selected according to the purpose. From the viewpoint of balance, 1 to 10 is preferable, 1 to 5 is more preferable, and 1 or 2 is particularly preferable.
On the other hand, the number of ethylenically unsaturated sites contained in the molecule is not particularly limited as long as it is 2 or more, and can be appropriately selected according to the purpose. 10 is preferable, 2 to 6 is more preferable, and 2 to 4 is particularly preferable.

The molecular weight of the sulfur-containing polyfunctional monomer in the present invention is preferably 120 to 3,000, more preferably 120 to 1,500, from the viewpoint of the flexibility of the formed film.
Moreover, although the sulfur-containing polyfunctional monomer in this invention may be used independently, you may use it as a mixture with the polyfunctional polymerizable compound and monofunctional polymerizable compound which do not have a sulfur atom in a molecule | numerator.
Specific examples of the polymerizable compound having a sulfur atom in the molecule include those described in paragraphs 0032 to 0037 of JP-A-2009-255510, and the compounds described herein are used in the present invention. Also good.

Component D in the resin composition of the present invention may be used alone or in combination of two or more.
The content of Component D contained in the resin composition of the present invention is preferably 2 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 10 to 30% by weight based on the total solid content.

<(Component E) Polymerization initiator>
The resin composition for laser engraving of the present invention can contain (Component E) a polymerization initiator.
As the polymerization initiator, those known to those skilled in the art can be used without limitation, but a radical polymerization initiator is preferable.
Hereinafter, although the radical polymerization initiator which is a preferable polymerization initiator is explained in full detail, this invention is not restrict | limited by these description.
The radical polymerization initiator may be a photo radical polymerization initiator or a thermal radical polymerization initiator, but is preferably a thermal radical polymerization initiator.

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

  In the present invention, from the viewpoint of engraving sensitivity and a good relief edge shape when applied to a relief forming layer of a relief printing plate precursor, (c) an organic peroxide and (l) an azo compound are more Preferably, (c) an organic peroxide is particularly preferable.

(A) aromatic ketones, (b) onium salt compounds, (d) thio compounds, (e) hexaarylbiimidazole compounds, (f) ketoxime ester compounds, (g) borate compounds, (h) azinium compounds As (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-isopropylcumylper) Oxycarbonyl) benzophenone, di-tertiary butyl diperoxyisophthalate, tertiary butyl peroxy Peroxide esters such as benzoate are preferred.

(L) Azo-based compound Preferred as a radical polymerization initiator that can be used in the present invention (l) As the azo-based compound, 2,2′-azobisisobutyronitrile, 2,2′-azobispropionitrile 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2 '-Azobis (4-methoxy-2,4-dimethylvaleronitrile), 4,4'-azobis (4-cyanovaleric acid), dimethyl 2,2'-azobisisobutyrate, 2,2'-azobis (2-methyl) Propionamidoxime), 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl)- 2 Hydroxyethyl] 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 the present invention, the organic peroxide (c) is particularly preferable as the polymerization initiator in the present invention from the viewpoint of the crosslinkability of the film (relief forming layer) and the improvement of engraving sensitivity.

From the viewpoint of engraving sensitivity, an embodiment in which (c) the organic peroxide and (Component A) a polymer having a glass transition temperature of room temperature (20 ° C.) or higher as the main polymer is particularly preferred.
This is because when an organic peroxide is used to cure the relief forming layer by thermal crosslinking, unreacted organic peroxide that does not participate in radical generation remains, but the remaining organic peroxide is self-reactive. Works as an additive and decomposes exothermically during laser engraving. As a result, it is presumed that the engraving sensitivity is increased because the heat generated is added to the irradiated laser energy.
In particular, when the glass transition temperature of the binder polymer is above room temperature, the heat generated from the decomposition of the organic peroxide is efficiently transferred to the binder polymer and effectively used for the thermal decomposition of the binder polymer itself. It is estimated that the sensitivity will be higher.
This effect is remarkable when carbon black is used as the photothermal conversion agent. This is because heat generated from carbon black is transferred to (c) organic peroxide, and heat is generated not only from carbon black but also from organic peroxide. This is because energy generation occurs synergistically.

Moreover, it is more preferable because the engraving sensitivity becomes extremely high by using a combination of an organic peroxide and a photothermal conversion agent described later, and an aspect in which an organic peroxide and a carbon black that is a photothermal conversion agent are combined is used. Most preferred.
This is because when an organic peroxide is used to cure the relief forming layer by thermal crosslinking, unreacted organic peroxide that does not participate in radical generation remains, but the remaining organic peroxide is self-reactive. Works as an additive and decomposes exothermically during laser engraving. As a result, the amount of heat generated is added to the irradiated laser energy, so that the engraving sensitivity is estimated to increase.

Component E in the resin composition of the present invention may be used alone or in combination of two or more.
The content of Component E contained in the resin composition of the present invention is preferably 0.1 to 5% by weight, more preferably 0.3 to 3% by weight, and more preferably 0.5 to 2% based on the total solid content. .5% by weight is particularly preferred.

<(Component F) Plasticizer>
The resin composition of the present invention preferably contains (Component F) a plasticizer from the viewpoint of imparting necessary flexibility as a flexographic plate.
As the plasticizer, those known as polymer plasticizers can be used, and are not limited. For example, described in pages 211 to 220 of Polymer Dictionary (First Edition, published by Maruzen Co., Ltd., 1994). Adipic acid derivatives, azelaic acid derivatives, benzoyl acid derivatives, citric acid derivatives, epoxy derivatives, glycol derivatives, hydrocarbons and derivatives, oleic acid derivatives, phosphoric acid derivatives, phthalic acid derivatives, polyesters, ricinoleic acid derivatives, sebacic acid derivatives , Stearic acid derivatives, sulfonic acid derivatives, terpenes and derivatives, trimellitic acid derivatives. Among these, an adipic acid derivative, a citric acid derivative, and a phosphoric acid derivative are preferable, and a phosphoric acid derivative is more preferable from the viewpoint of the effect of lowering the glass transition temperature.
As the adipic acid derivative, dibutyl adipate and 2-butoxyethyl adipate are preferable.
As the citric acid derivative, tributyl citrate is preferable.
Examples of phosphoric acid derivatives include tributyl phosphate, tri-2-ethylhexyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, t-butylphenyl phosphate, 2-ethylhexyl phosphate And diphenyl. Among these, triphenyl phosphate, cresyl diphenyl phosphate, and tricresyl phosphate are preferable, and cresyl diphenyl phosphate is more preferable.
Component F may use only 1 type and may use 2 or more types together.
From the viewpoint of lowering the glass transition temperature to room temperature or lower, the content of Component F is preferably 1 to 50% by weight, preferably 10 to 40% by weight, in terms of solid content, with the total weight of the resin composition being 100% by weight. Is more preferable, and 20 to 30% by weight is particularly preferable.

<(Component G) at least one oxy compound of a metal or metalloid (metalloid) selected from Group 1 to 16 of the periodic table>
The resin composition of the present invention preferably contains (Component G) at least one oxy compound of a metal or metalloid (metalloid) selected from Groups 1 to 16 of the periodic table.
The metal or metalloid selected from group 1-16 of the periodic table is not particularly limited as long as it is selected from group 1-16 of the periodic table, but alkali metals (Li, Na, K, Rb, Cs, Fr), alkaline earth metals (Be, Mg, Ca, Sr, Ba, Ra), aluminum, silicon, phosphorus, titanium, germanium, arsenic, zirconium, tin, zinc, cadmium, bismuth, indium, scandium and antimony Is preferred.
Among these, alkaline earth metals, aluminum, silicon, phosphorus, titanium, germanium, arsenic, zirconium, tin, zinc, and bismuth are preferable from the viewpoint of engraving sensitivity, and alkaline earth metals, aluminum, and titanium (preferably valences are preferred) 4) Zirconium, tin, zinc and bismuth are more preferred, and alkaline earth metals, aluminum, titanium (preferably valence 4), tin, zinc and bismuth are particularly preferred.
Examples of the oxy compound (oxygen-containing compound) include alkoxides, phenoxides, enolates, carbonates, acetates or carboxylates and oxides of the above metals or metalloids.
If desired, the organic portion of the oxy compound can be partially polyvalent, such as those derived from polyhydric alcohols (eg, glycol or glycerol), polyvinyl alcohol, or hydroxycarboxylic acids. Chelate compounds may be used. When carbon atoms are present, typically the number of carbon atoms per metal or metalloid ranges from 4 to 24.
In the present invention, a carboxylate of aluminum, zinc, tin or bismuth is preferable, and a carboxylate of zinc is more preferable.
Specifically, zinc acetate, zinc 2-ethylhexylate, tin 2-ethylhexylate, bismuth tris (2-ethylhexanoate), bis (2-ethylhexylate) hydroxyaluminum are particularly preferred, and zinc 2-ethylhexylate is preferred. Most preferred.
The content of component G is preferably 0.01 to 20% by weight, more preferably 0.5 to 10% by weight, and more preferably 1 to 5% with respect to the total solid content of the resin composition from the viewpoint of engraving sensitivity and film property. Weight percent is particularly preferred.

<Solvent>
It is preferable to use a solvent when preparing the resin composition for laser engraving of the present invention.
As the solvent, an organic solvent is preferably used.
Preferred specific examples of the aprotic organic solvent include acetonitrile, tetrahydrofuran, dioxane, toluene, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl acetate, butyl acetate, ethyl lactate, N, N-dimethylacetamide, N -Methylpyrrolidone, dimethyl sulfoxide are mentioned.
Preferable specific examples of the protic organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, ethylene glycol, diethylene glycol, and 1,3-propanediol.
Among these, propylene glycol monomethyl ether acetate is particularly preferable.
There is no restriction | limiting in particular in the usage-amount of a solvent, What is necessary is just to adjust a usage-amount as needed.

<Other additives>
In the resin composition for laser engraving of the present invention, various known additives can be appropriately blended as long as the effects of the present invention are not impaired. Examples include waxes, process oils, metal oxides, antiozonants, antioxidants, polymerization inhibitors, colorants, etc. These may be used alone or in combination of two or more. May be.

<Compound having only one hydrolyzable silyl group and / or silanol group>
Moreover, you may use the compound which has only one hydrolyzable silyl group and / or silanol group as another component.
Specific examples of the compound having only one hydrolyzable silyl group and / or silanol group include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxy. Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, p-styryltrimethoxysilane, γ -Methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyl Rudimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyl Triethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, mercaptomethyltrimethoxysilane, dimethoxy-3-mercaptopropylmethylsilane, 2- ( 2-aminoethylthioethyl) diethoxymethylsilane, 3- (2-acetoxyethylthiopropyl) dimethoxymethylsilane, 2- (2-aminoethylthioethyl) triethoxysilane, dimethoxymethyl-3- (3-phenoxypropyl) Thiop Pyr) silane, γ-chloropropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, trimethylsilanol, diphenylsilanediol, triphenylsilanol, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane Dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane and the like.

<A photothermal conversion agent capable of absorbing light having a wavelength of 700 to 1,300 nm>
The resin composition for laser engraving of the present invention preferably further contains a photothermal conversion agent capable of absorbing light having a wavelength of 700 to 1,300 nm (hereinafter also simply referred to as “photothermal conversion agent”). That is, it is considered that the photothermal conversion agent in the present invention promotes thermal decomposition of a cured product 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 crosslinked relief forming layer in the relief printing plate precursor for laser engraving of the present invention is used for laser engraving using a laser emitting a infrared ray of 700 to 1,300 nm (YAG laser, semiconductor laser, fiber laser, surface emitting laser, etc.) as a light source In addition, as the photothermal conversion agent, it is preferable to use a compound having a maximum absorption wavelength at 700 to 1,300 nm.
Various dyes or pigments are used as the photothermal conversion agent that can be used in the present invention.

  Among the photothermal conversion agents, as the dye, commercially available dyes and known ones described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, those having a maximum absorption wavelength at 700 nm to 1,300 nm are preferably mentioned, and azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes , Diimmonium compounds, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, and the like.

  Dyes preferably used in the present invention include cyanine dyes such as heptamethine cyanine dyes, oxonol dyes such as pentamethine oxonol dyes, phthalocyanine dyes, and paragraphs 0124 to 0137 of JP-A-2008-63554. Mention may be made of dyes.

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

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

(Method for producing resin composition for laser engraving)
The method for producing a resin composition for laser engraving of the present invention comprises a dispersion step of dispersing a filler of component C with a dispersion polymer of component B, and a polymer dispersion of filler prepared in the dispersion step and a binder polymer of component A And a mixing step of mixing the two.
As a method of dispersing the filler with the component B, a known dispersion technique used for ink production, toner production, or the like can be used. For details, the method described in “Latest Pigment Applied Technology” (CMC Publishing, 1986) can be used.
The filler dispersion and the binder polymer may be mixed by mixing the binder into the mixing container containing the dispersion, or conversely mixing the dispersion into the mixing container containing the binder, or separating the dispersion and the binder separately. It may be charged from the container to the mixing container and mixed. It is only necessary that the filler is dispersed before mixing the binder polymer and the filler dispersion.

(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 a relief forming layer having a crosslinkability made of a resin composition for laser engraving is cured by light and / or heat before being crosslinked. It refers to both or either state.
The relief printing plate precursor for laser engraving of the present invention preferably has a thermally crosslinked crosslinked relief forming layer.
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.
In the present invention, the “crosslinked relief forming layer” refers to a layer obtained by crosslinking the relief forming layer. The crosslinking is preferably performed by light and / or heat. The crosslinking is not particularly limited as long as the resin composition is cured.
A “relief printing plate” is produced by laser engraving a printing plate precursor having a crosslinked relief forming layer.
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 a crosslinkable layer.
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.
Hereinafter, the case where the relief forming layer is formed into a sheet shape will be mainly described as an example.

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

<Adhesive layer>
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.
Examples of the material (adhesive) that can be used for the adhesive layer include 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.

  When the protective film cannot be peeled or when it is difficult to adhere to the relief forming layer, a slip coat layer may be provided between both layers. The material used for the slip coat layer is a resin that can be dissolved or dispersed in water, such as polyvinyl alcohol, polyvinyl acetate, partially saponified polyvinyl alcohol, hydroxyalkyl cellulose, alkyl cellulose, polyamide resin, etc. It is preferable that

(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 comprises a layer forming step of 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 crosslinking and obtaining a relief printing plate precursor having a crosslinked relief forming layer, and a layer forming step of forming a relief forming layer comprising the resin composition for laser engraving of the present invention, and More preferably, the production method includes a crosslinking step of thermally crosslinking the relief forming layer to obtain a relief printing plate precursor having the crosslinked relief forming layer.

Thereafter, a protective film may be laminated on the relief forming layer as necessary. Lamination can be performed by pressure-bonding the protective film and the relief forming layer with a heated calendar roll or the like, or by bringing the protective film into close contact with the relief forming layer impregnated with a small amount of solvent on the surface.
When using a protective film, you may take the method of laminating | stacking a relief forming layer on a protective film first, and laminating a support body then.
When providing an adhesive layer, it can respond by using the support body which apply | coated the adhesive layer. When providing a slip coat layer, it can respond by using the protective film which apply | coated the slip coat layer.

<Layer formation process>
The plate making method of the relief printing plate for laser engraving of the present invention preferably includes a layer forming step of forming a relief forming layer comprising the resin composition for laser engraving of the present invention.
As a method for forming the relief forming layer, the resin composition for laser engraving of the present invention is prepared. A method of preparing the resin composition for laser engraving of the present invention, casting the resin composition for laser engraving of the present invention on a support and drying it in an oven to remove the solvent is preferably exemplified.

  The thickness of the (crosslinked) relief forming layer in the relief printing plate precursor for laser engraving is preferably 0.05 mm or more and 10 mm or less, more preferably 0.05 mm or more and 7 mm or less, and more preferably 0.05 mm or more and 3 mm or less before and after crosslinking. Particularly preferred.

<Crosslinking process>
The method for producing a relief printing plate precursor for laser engraving of the present invention is a production method including a crosslinking step of obtaining a relief printing plate precursor having a crosslinked relief forming layer by crosslinking the relief forming layer with light and / or heat. Is preferred.
When the relief forming layer contains a photopolymerization initiator, the relief forming layer can be crosslinked by irradiating the relief forming layer with an actinic ray that triggers the photopolymerization initiator.
In general, light is applied to the entire surface of the relief forming layer. Examples of light (also referred to as “active light”) include visible light, ultraviolet light, and electron beam, and 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.

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

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

When the crosslinking step is a step of crosslinking by light, an apparatus for irradiating actinic rays is relatively expensive, but the printing plate precursor does not become high temperature, so there are almost no restrictions on the raw materials of the printing plate precursor. Absent.
When the cross-linking step is a step of cross-linking by heat, there is an advantage that an extra expensive apparatus is not required, but since the printing plate precursor becomes high temperature, the thermoplastic polymer that becomes flexible at high temperature is not heated. The raw materials to be used must be carefully selected, such as the possibility of deformation.
In the case of thermal crosslinking, it is preferable to add a thermal polymerization initiator. As the thermal polymerization initiator, it can be used as a commercial thermal polymerization initiator for free radical polymerization. Examples of such a thermal polymerization initiator include a compound containing a suitable peroxide, hydroperoxide, or azo group. Representative vulcanizing agents can also be used for crosslinking. Thermal crosslinking can also be performed by adding a heat-curable resin, such as an epoxy resin, as a crosslinking component to the layer.

(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, the relief forming layer is crosslinked by light and / or heat, and a crosslinked relief forming layer is formed. A relief printing plate precursor comprising the resin composition for laser engraving of the present invention, preferably comprising: a crosslinking step for obtaining a relief printing plate precursor comprising: and a engraving step for laser engraving the relief printing plate precursor comprising the crosslinked relief forming layer A layer forming step for forming a layer, a crosslinking step for thermally crosslinking the relief forming layer to obtain a relief printing plate precursor having a crosslinked relief forming layer, and an engraving step for laser engraving the relief printing plate precursor having the crosslinked relief forming layer More preferably, it contains.
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.
In the relief printing plate of the present invention, a water-based ink can be suitably used during printing.
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.

<Engraving process>
The plate making method of the relief printing plate of the present invention preferably includes an engraving step of laser engraving the relief printing plate precursor having the crosslinked relief forming layer.
The engraving step is a step of forming a relief layer by laser engraving the crosslinked relief forming layer crosslinked in the crosslinking step. Specifically, it is preferable to form a relief layer by engraving a crosslinked crosslinked relief forming layer by irradiating a laser beam corresponding to a desired image. Moreover, the process of controlling a laser head with a computer based on the digital data of a desired image, and carrying out scanning irradiation with respect to a bridge | crosslinking relief forming layer is mentioned preferably.
In this engraving process, an infrared laser is preferably used. When irradiated with an infrared laser, the molecules in the crosslinked relief forming layer undergo molecular vibrations and generate heat. When a high-power laser such as a carbon dioxide laser or YAG laser is used as an infrared laser, a large amount of heat is generated in the laser irradiation part, and molecules in the crosslinked relief forming layer are selectively cut by molecular cutting or ionization. That is, engraving is performed. The advantage of laser engraving is that the engraving depth can be set arbitrarily, so that the structure can be controlled three-dimensionally. For example, a portion that prints fine halftone dots can be engraved shallowly or with a shoulder so that the relief does not fall down due to printing pressure, and a portion of a groove that prints fine punched characters is engraved deeply As a result, the ink is less likely to be buried in the groove, and it is possible to suppress the crushing of the extracted characters.
In particular, when engraving with an infrared laser corresponding to the absorption wavelength of the photothermal conversion agent, the crosslinked relief forming layer can be selectively removed with higher sensitivity, and a relief layer having a sharp image can be obtained.

As the infrared laser used in the engraving process, a carbon dioxide laser (CO ₂ laser) or a semiconductor laser is preferable from the viewpoints of productivity and cost. In particular, a semiconductor infrared laser with a fiber (FC-LD) is preferably used. In general, a semiconductor laser can be downsized with high efficiency and low cost in laser oscillation compared to a CO ₂ laser. Moreover, since it is small, it is easy to form an array. Furthermore, the beam shape can be controlled by processing the fiber.
The semiconductor laser preferably has a wavelength of 700 to 1,300 nm, more preferably 800 to 1,200 nm, still more preferably 860 to 1,200 nm, and particularly preferably 900 to 1,100 nm.

Moreover, since the semiconductor laser with a fiber can output a laser beam efficiently by attaching an optical fiber, it is effective for the engraving process in the present invention. Furthermore, the beam shape can be controlled by processing the fiber. For example, the beam profile can have a top hat shape, and energy can be stably given to the plate surface. Details of the semiconductor laser are described in “Laser Handbook 2nd Edition” edited by the Laser Society, practical laser technology, and the Institute of Electronics and Communication Engineers of Japan.
Also, a plate making apparatus equipped with a fiber-coupled semiconductor laser that can be suitably used in a method for making a relief printing plate using the relief printing plate precursor of the present invention is disclosed in JP 2009-172658 A and JP 2009-214334 A. It is described in detail in the official gazette and can be used for making a relief printing plate according to the present invention.

Hereinafter, the configuration of the plate making apparatus 11 including the fiber-coupled semiconductor laser recording apparatus 10 used in the present invention will be described with reference to FIG.
A plate making apparatus 11 including a fiber-coupled semiconductor laser recording apparatus 10 that can be used in the present invention rotates a drum 50 having a relief printing plate precursor F (recording medium) of the present invention mounted on its outer peripheral surface in the main scanning direction. A plurality of laser beams corresponding to the image data of the image to be engraved (recorded) are simultaneously emitted onto the relief printing plate precursor F, and the exposure head 30 is moved at a predetermined pitch in the sub-scanning direction (S) perpendicular to the main scanning direction. By scanning, the two-dimensional image is engraved (recorded) on the relief printing plate precursor F at high speed. Further, when engraving a narrow area (precision engraving such as fine lines and halftone dots), the relief printing plate precursor F is shallowly engraved, and when engraving a wide area, the relief printing plate precursor F is deeply engraved.

  As shown in FIG. 1, the plate making apparatus 11 is equipped with a relief printing plate precursor F on which an image is recorded by engraving with a laser beam, and the arrow R in FIG. 1 is moved so that the relief printing plate precursor F moves in the main scanning direction. A drum 50 that is rotationally driven in the direction and the laser recording apparatus 10 are included. The laser recording apparatus 10 includes a light source unit 20 that generates a plurality of laser beams, an exposure head 30 that exposes a plurality of laser beams generated by the light source unit 20 onto a relief printing plate precursor F, and the exposure head 30 in a sub-scanning direction. And an exposure head moving unit 40 that is moved along the direction.

  The light source unit 20 includes semiconductor lasers 21A and 21B each composed of a broad area semiconductor laser in which one ends of the optical fibers 22A and 22B are individually coupled, and a light source substrate 24A on which the semiconductor lasers 21A and 21B are arranged. , 24B, adapter boards 23A, 23B that are vertically attached to one end of the light source boards 24A, 24B and that are provided with a plurality of adapters for the SC type optical connectors 25A, 25B (the same number as the semiconductor lasers 21A, 21B); An LD driver substrate that is horizontally mounted on the other end of 24A and 24B and provided with an LD driver circuit 26 that drives the semiconductor lasers 21A and 21B in accordance with image data of an image engraved (recorded) on the relief printing plate precursor F 27A and 27B.

  The exposure head 30 includes a fiber array unit 300 that collectively emits laser beams emitted from the plurality of semiconductor lasers 21A and 21B. The fiber array section 300 includes laser beams emitted from the semiconductor lasers 21A and 21B by a plurality of optical fibers 70A and 70B connected to SC type optical connectors 25A and 25B connected to adapter boards 23A and 23B, respectively. Is transmitted.

  As shown in FIG. 1, in the exposure head 30, a collimator lens 32, an aperture member 33, and an imaging lens 34 are arranged in order from the fiber array unit 300 side. The opening member 33 is arranged so that the opening is positioned at the far field as viewed from the fiber array unit 300 side. As a result, an equivalent light amount limiting effect can be given to all laser beams emitted from the optical fiber end portions of the plurality of optical fibers 70A and 70B in the fiber array unit 300.

The laser beam is imaged in the vicinity of the exposure surface (front surface) FA of the relief printing plate precursor F by the imaging means composed of the collimator lens 32 and the imaging lens 34.
In the present invention, since the beam shape can be changed in the semiconductor laser with a fiber, in the present invention, the imaging position (imaging position) P is in the range from the exposure surface FA to the inside (the laser beam traveling direction side). Thus, it is desirable to control the beam diameter of the exposure surface (relief forming layer surface) FA in the range of 10 μm to 80 μm from the viewpoints of performing efficient engraving and improving fine line reproducibility.

The exposure head moving unit 40 is provided with a ball screw 41 and two rails 42 arranged so that the longitudinal direction thereof is along the sub-scanning direction. By operating a sub-scanning motor that rotationally drives the ball screw 41, The pedestal portion on which the exposure head 30 is provided can be moved in the sub-scanning direction while being guided by the rails 42. Further, the drum 50 can be rotated in the direction of arrow R in FIG. 1 by operating a main scanning motor (not shown), whereby main scanning is performed.
Such an apparatus is described in detail in Japanese Patent Application Laid-Open No. 2009-172658 proposed by the present applicant, and can be used in the present invention.

Further, in controlling the shape to be engraved, it is possible to change the shape of the engraving region by changing the amount of energy supplied to the semiconductor laser without changing the beam shape of the semiconductor laser with fiber.
Specifically, there are a method of controlling by changing the output of the semiconductor laser and a method of controlling by changing the laser irradiation time.

In the plate making method of the 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 (cleaning) the engraved surface of the relief layer 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 adheres to the engraving surface after the above process, 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 rinse liquid is preferably 14 or less, more preferably 13.5 or less, and further preferably 13.2 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, amphoteric 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 weight and more preferably 0.05 to 10% by weight with respect to the total weight of the rinse liquid.

As described above, a relief printing plate having a relief layer on the surface of an arbitrary substrate such as a support can be obtained.
The thickness of the relief layer of the relief printing plate is preferably from 0.05 mm to 10 mm, more preferably from 0.05 mm to 7 mm, from the viewpoint of satisfying various printability such as abrasion resistance and ink transferability. Hereinafter, it is particularly preferably 0.05 mm or more and 3 mm or less.

The Shore A hardness of the relief layer of the relief printing plate is preferably 50 ° or more and 90 ° or less. When the Shore A hardness of the relief layer is 50 ° or more, even if the fine halftone dots formed by engraving are subjected to the strong printing pressure of the relief printing press, they do not collapse and can be printed normally. In addition, when the Shore A hardness of the relief layer is 90 ° or less, it is possible to prevent faint printing in a solid portion even in flexographic printing with a kiss touch.
In addition, the Shore A hardness in this specification is a numerical value obtained by indenting and deforming an indenter (called a push needle or an indenter) on a surface to be measured at 25 ° C., and measuring the deformation amount (indentation depth). This is a value measured with a durometer (spring type rubber hardness meter).

  The relief printing plate of the present invention is particularly suitable for printing with water-based ink by a flexographic printing machine, but printing is possible with any of water-based ink, oil-based ink and UV ink by a relief printing press. In addition, printing with UV ink by a flexographic printing machine is also possible.

  Hereinafter, the present invention will be described in detail with reference to examples. Unless otherwise specified, “part” means “part by weight” and “%” means “% by weight”.

The compounds used in Examples and Comparative Examples are shown below.
Polyvinyl butyral (Denka butyral # 3000-2, weight average molecular weight: 90,000, manufactured by Denki Kagaku Kogyo Co., Ltd.)
・ Polyvinyl butyral (ESREC BM-S, weight average molecular weight: 53,000, manufactured by Sekisui Chemical Co., Ltd.)
・ Polyvinyl butyral (ESREC BL-S, weight average molecular weight: 23,000, manufactured by Sekisui Chemical Co., Ltd.)
・ Polyvinyl butyral (ESREC BL-1, weight average molecular weight: 19,000, manufactured by Sekisui Chemical Co., Ltd.)
・ Polyvinyl butyral (ESREC BL-1H, weight average molecular weight: 20,000, manufactured by Sekisui Chemical Co., Ltd.)
・ Polyvinyl butyral (ESREC BL-10, weight average molecular weight: 15,000, manufactured by Sekisui Chemical Co., Ltd.)
・ Polyvinyl butyral (Movital B60H, weight average molecular weight: 90,000, manufactured by Kuraray Co., Ltd.)
・ Ketjen Black EC600JD (Lion Corporation carbon black, average primary particle size 34.0 nm)
R7200 (Nippon Aerosil Co., Ltd. silica particles, average particle size 12 nm)
・ 200CF (Nippon Aerosil Co., Ltd. silica particles, average particle size 12 nm)

Monomer 1 (bifunctional acrylate compound shown below)

・ Perbutyl Z (t-butyl peroxybenzoate, manufactured by NOF Corporation)
・ Irgacure 184 (α-hydroxyketone, manufactured by Ciba Specialty Chemicals) ・ Cresyl diphenyl phosphate (plasticizer, manufactured by Tokyo Chemical Industry Co., Ltd.)
・ Zinc 2-ethylhexylate (manufactured by Hope Pharmaceutical Co., Ltd.)

<Method for dispersing filler by component B>
The filler was dispersed in the dispersion polymer by the following method.
The following formulation was dispersed with a motor mill M-200 (manufactured by Eiger) at a peripheral speed of 9 m / s for 5 hours using zirconia beads having a diameter of 1.0 mm to obtain a filler dispersion.
15 parts of filler shown in Table 1 (dry weight)
10 parts of dispersion polymer shown in Table 1 75 parts of propylene glycol monomethyl acetate

<Preparation of Example 1 (Relief Printing Plate Precursor for Laser Engraving Having a Thermally Crosslinked Relief Forming Layer)>
As main binders, 40 parts of polyvinyl butyral “ESREC BM-S”, carbon black “Ketjen Black EC600JD” (hereinafter also referred to as CB) 10 parts of dispersion (total amount of filler and dispersion polymer), cresyl diphenyl phosphate 25 Part, 3 parts zinc 2-ethylhexylate and 100 parts propyl glycol monoethyl ether acetate (PGMEA) as a solvent are placed in a three-necked flask equipped with a stirring blade and a condenser and heated at 70 ° C. for 120 minutes with stirring. And dissolved.
Thereafter, 20 parts of monomer 1 was further added and stirred for 30 minutes. Thereafter, 2 parts of perbutyl Z was added and stirred at 70 ° C. for 10 minutes. By this operation, a fluid resin composition for laser engraving was obtained.
A spacer (frame) of a predetermined thickness is placed on the PET substrate, and the resin composition for laser engraving is gently cast so as not to flow out of the spacer (frame), and is dried and thermally crosslinked in an oven at 100 ° C. for 3 hours. Then, a relief forming layer having a thickness of about 1 mm was provided, and a relief printing plate precursor for laser engraving of Example 1 was produced.

<Production of Examples 2 to 8>
Example 2 was conducted in the same manner as in the relief printing plate precursor for laser engraving of Example 1, except that the binder polymer of Component A, the filler dispersion polymer of Component B, and the filler of Component C were changed to the types shown in Table 1. Relief printing plate precursors for laser engraving of 8 to 8 were respectively prepared.

<Production of Example 9 (Relief Printing Plate Precursor for Laser Engraving with Photocrosslinked Relief Forming Layer)>
As binder polymer, 40 parts of polyvinyl butyral “ESREC BM-S”, 10 parts of “Aerosil 200CF” dispersion (total amount of filler and dispersion polymer), 25 parts of cresyl diphenyl phosphate, 3 parts of zinc 2-ethylhexylate, solvent As a solution, 100 parts of propyl glycol monoethyl ether acetate (PGMEA) was placed in a three-necked flask equipped with a stirring blade and a cooling tube, and dissolved by heating at 70 ° C. for 120 minutes with stirring.
Thereafter, 20 parts of monomer 1 was further added and stirred for 30 minutes. Thereafter, 2 parts of Irgacure 184 was added and stirred at 70 ° C. for 10 minutes. By this operation, a fluid resin composition for laser engraving was obtained.
A spacer (frame) with a predetermined thickness is placed on the PET substrate, and the resin composition for laser engraving is gently cast to such an extent that it does not flow out of the spacer (frame). Then, using an exposure machine using a metal halide lamp manufactured by Ushio Corp., exposure was performed so that the exposure amount on the plate surface was 2,000 mJ / cm ² , and relief printing for laser engraving of Example 9 was performed. An original plate was prepared.

<Preparation of Comparative Example 1 (Relief Printing Plate Precursor for Laser Engraving)>
For the laser engraving of Comparative Example 1 in the same manner as the relief printing plate precursor for laser engraving of Example 1, except that the filler dispersion polymer of Component B was not added and 6.6 parts of CB was added as the filler of Component C. A relief printing plate precursor was prepared.

<Production of Comparative Example 2>
In the same manner as in the relief printing plate precursor for laser engraving of Example 1, except that the binder polymer of Component A, the filler dispersion polymer of Component B, and the filler of Component C were changed to the types shown in Table 1, Comparative Example 2 A relief printing plate precursor for laser engraving was prepared.

<Production of Comparative Example 3>
As the binder polymer of component A, two types of binders shown in Table 1 were added in half the amount of the binder of Example 1, respectively, the dispersion polymer of component B was eliminated, and the filler of component C was changed to the type described in Table 1. A relief printing plate precursor for laser engraving of Comparative Example 3 was produced in the same manner as the relief printing plate precursor for laser engraving of Example 1 except that.

<Preparation of relief printing plate for laser engraving>
In Examples 1 to 8 and Comparative Examples 1 to 3, the semiconductor laser engraving machine was equipped with a fiber-coupled semiconductor laser (FC-LD) SDL-6390 (manufactured by JDSU, wavelength: 915 nm) with a maximum output of 8.0 W. The laser recording apparatus shown in FIG. 1 (described as “FC-LD” in Table 1 below) was used. Engraving was performed with a semiconductor laser engraving machine under conditions of laser output: 6 W, head speed: 100 mm / second, pitch setting: 2,400 DPI.
In Example 9, ADFLEX (manufactured by Comtex Co., Ltd., wavelength: 10,600 nm, described as “CO ₂ ” in Table 1 below) was used as the laser engraving machine.
For each of the obtained printing plate precursors for laser engraving, a halftone dot pattern (2 × 2 dots, high height) was obtained with the laser engraving machine under the conditions of output: 12 W, head speed: 200 mm / second, pitch setting: 2,400 DPI. 300 μm) was engraved, and each relief printing plate was obtained.

<Evaluation of sculpture residue cleaning>
On each relief printing plate engraved by the above method, a 0.01 N aqueous KOH solution (manufactured by Wako Pure Chemical Industries, Ltd.) is dropped with a dropper (about 100 ml / m ² ) so that the plate surface is evenly wetted. After standing for 1 minute, it was rubbed 20 times (total 30 seconds) in parallel with the plate with a load of 200 gf using a toothbrush (Lion Corporation Clinica Habrush Flat). Thereafter, the plate surface was washed with running water, the water on the plate surface was removed, and air-dried for about 1 hour.
The surface of the plate obtained by natural drying was observed with a microscope (manufactured by Keyence Co., Ltd.) having a magnification of 100 times, and the degree of engraving residue left on the plate was evaluated. The evaluation criteria are as follows.
A: No engraving residue remains on the plate.
○: Slight engraving residue remains on the bottom (recessed portion) of the image on the plate.
Δ: Engraving residue remains on the image convex portion and the image bottom portion (concave portion) on the plate.
X: Engraving residue is attached to the entire plate surface.
In addition, (double-circle), (circle), and (triangle | delta) are the ranges which do not have a problem practically.
<Evaluation of film strength>
The obtained relief printing plate precursor (thickness 1 mm) for laser engraving was punched using a dumbbell defined in JIS K 62533 and hooked on one end of a relief forming layer punched with a spring alone (max 1,000 g), The tip of the other side was pulled by hand, and the value of the load of the spring alone when it broke was inserted into the following equation to obtain.
Sheet strength [N / cm]) = Load at break [kg] × 9.8 [m / s ² ]) / 0.5 [cm]
The evaluation criteria are as follows.
◯: 4 N / cm or more Δ: 2 N / cm or more and less than 4 N / cm ×: less than 2 N / cm In addition, ◯ and Δ are ranges that have no practical problem.
<High-definition evaluation: Measurement of engraving fine line width>
In this evaluation, the minimum thin line width when an engraving depth of 2 μm or more was obtained was measured. It was evaluated that the smaller the fine line width, the better the engraving sensitivity and the fine line formability, and the higher definition image can be obtained. If it is 30 μm or less, there is no practical problem.
The engraving depth is the distance between the engraved position (height) and the unengraved position (height) when the flexographic printing plate is viewed in cross section, and is observed with a SEM (transmission electron microscope). Can be measured.

  From the results shown in Table 1, according to the present invention, the resin composition for laser engraving, which is excellent in engraving residue removal and film strength, and provides a high-definition image, the relief printing plate using the laser engraving resin composition It can be seen that an original plate and a relief printing plate can be provided.

10 Laser recording device (exposure device)
30 exposure head 32 collimator lens (imaging means)
34 Imaging lens (imaging means)
70A optical fiber 70B optical fiber 300 fiber array part
F Relief printing plate precursor (recording medium)
FA exposure surface (surface of relief printing plate precursor)

Claims (19)

(Component A) main polymer,
(Component B) a dispersion polymer having a weight average molecular weight smaller than that of the main polymer, and
(Component C) a filler,
Component C is previously dispersed by component B. A resin composition for laser engraving.   The resin composition for laser engraving according to claim 1, wherein the component A has a weight average molecular weight of 5,000 to 300,000.   The resin composition for laser engraving according to claim 1, wherein Component A and Component B are the same type of polymer.   The resin composition for laser engraving according to any one of claims 1 to 3, wherein the weight average molecular weight of Component B is not more than half of the weight average molecular weight of Component A.   The resin composition for laser engraving according to any one of claims 1 to 4, wherein both component A and component B are polyvinyl butyral.   The resin composition for laser engraving according to claim 5, wherein the difference in absolute value of mol% of hydroxyl groups between Component A and Component B is 0-10.   The resin composition for laser engraving according to any one of claims 1 to 6, wherein Component C is carbon black.   The resin composition for laser engraving according to claim 1, further comprising (Component D) an ethylenically unsaturated compound.   The resin composition for laser engraving according to any one of claims 1 to 8, further comprising (Component E) a polymerization initiator.   The resin composition for laser engraving according to any one of claims 1 to 9, further comprising (Component F) a plasticizer.   (Component G) The resin composition for laser engraving according to any one of claims 1 to 10, further comprising at least one oxy compound of a metal or metalloid selected from Groups 1 to 16 of the periodic table. A dispersion step of pre-dispersing component C with component B; and
The manufacturing method of the resin composition for laser engraving of any one of Claims 1-11 including the mixing process which mixes the dispersion and component A which were prepared at the said dispersion | distribution process.   A relief printing plate precursor for laser engraving having a relief forming layer comprising the resin composition for laser engraving according to any one of claims 1 to 11.   A relief printing plate precursor for laser engraving, comprising a crosslinked relief forming layer obtained by thermally crosslinking the relief forming layer comprising the resin composition for laser engraving according to any one of claims 1 to 11. 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 11, 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 layer forming step of forming a relief forming layer comprising the resin composition for laser engraving according to any one of claims 1 to 11,
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; 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 16, wherein the laser engraving is performed with a laser having a wavelength of 700 to 1,300 nm.   The plate-making method of the relief printing plate of Claim 16 or 17 which further includes the washing | cleaning process of wash | cleaning the relief layer surface after engraving with water or aqueous solution.   The relief printing plate which has a relief layer manufactured by the plate-making method of the relief printing plate of any one of Claims 16-18.

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