JP2009209248A - Photocurable coating composition, overprint and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocurable coating composition excellent in surface smoothness, non-tackiness (surface tackiness control) and odor control, an overprint obtained by applying and curing the photocurable coating composition, and a method for producing the overprint. <P>SOLUTION: The photocurable coating composition contains an onium salt containing a di- or higher valent anion and a polymerizable compound. The overprint using the photocurable coating composition and the method for producing the overprint are also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photocurable coating composition, an overprint, and a method for producing the same. More specifically, the present invention relates to a photocurable coating composition that can be cured by irradiation with active radiation such as an electron beam and ultraviolet rays. In particular, light for coating an image created by arranging ink and / or toner on a printing substrate (image receiving substrate) by a method such as planographic printing, relief printing, intaglio printing, screen printing, ink jetting, and electrophotography. The present invention relates to a curable coating composition. More particularly, it relates to photocurable overprint compositions that can be used particularly suitably for coating toner-based prints printed by electrophotography.

In recent years, a large amount of photocurable compositions, particularly curable compositions using ultraviolet rays, have been used. Examples of the curable composition include printing ink, overcoat varnish, paint, adhesive, and photoresist.
In particular, by applying overprint coating on toner-based image information such as electrophotography, the protection of printed matter is improved, and glossy printed matter is a product that replaces silver salt photographic prints. Has attracted attention.
In the electrophotographic method in which a toner-based printed matter is obtained, an electrostatic charge is formed on the surface of the latent image holding member by uniformly charging the surface of the latent image holding member, for example, a photoreceptor. Then, the uniformly charged area is selectively released by the activation irradiation pattern corresponding to the image of the original. The latent image charge pattern remaining on the surface corresponds to the areas not exposed to irradiation. The photoreceptor is then passed through one or more development housings containing toner, so that the toner adheres in a charge pattern due to electrostatic attraction, thereby visualizing the latent image charge pattern. The developed image is then fixed to the imaging surface or transferred to a printing substrate, such as paper, and fixed to it by a suitable fixing technique to obtain an electrophotographic print, i.e. a toner-based print. .

As a known method for protecting a printed matter, it has been proposed to apply an overprint coating to the printed matter. For example, Patent Documents 1 and 2 propose a method of covering the surface by performing fixing after transferring a transparent toner onto a toner-based image, such as electrophotography.
Patent Document 3 proposes a method of performing overprint coating by applying a liquid film coating that can be cured by ultraviolet rays or the like, and polymerizing (crosslinking) the coating components with light.
In addition, Patent Document 4 discloses a polyfunctional alkoxylated acrylic monomer or polycrystal comprising a radiation curable oligomer selected from the group consisting of trifunctional unsaturated acrylic resins and one or more di-acrylates or tri-acrylates. An overprint composition comprising a radiation curable monomer selected from the group consisting of alkoxylated acrylic monomers, at least one photopolymerization initiator, and at least one surfactant is disclosed.

  On the other hand, with respect to the polymerization initiator, Patent Document 5 discloses a polymer-type initiator in which a phenyl ketone derivative having a polymerization initiating ability is introduced. A copolymerizable monoacrylate photopolymerization initiator is also disclosed in Patent Document 6.

  Patent Document 7 contains, on a support, (A) a photothermal conversion agent, (B) a compound having a polymerizable unsaturated group, and (C) an onium salt having a divalent or higher anion as a counter ion. However, there is disclosed a negative lithographic printing plate precursor for heat mode, which is provided with a photosensitive layer that can be recorded with an infrared laser.

JP-A-11-70647 JP 2003-241414 A JP-A-61-210365 JP-A-2005-321882 JP 7-33811 A European Patent No. 377191 JP 2002-268217 A

  The object of the present invention is to provide a photocurable coating composition excellent in surface smoothness, non-tackiness (surface tackiness suppression), and odor control, an overprint obtained by applying and curing the photocurable coating composition, And it is providing the manufacturing method of an overprint.

The above object has been achieved by <1> to <10> described below.
<1> A photocurable coating composition comprising an onium salt containing a divalent or higher anion and a polymerizable compound,
<2> The photocurable coating composition according to <1>, which has substantially no absorption in the visible region,
<3> The photocurable coating composition according to <1> or <2>, wherein the onium salt is a sulfonium salt and / or an iodonium salt,
<4> The photocurable coating composition according to any one of <1> to <3>, which is for overprinting,
<5> The photocurable coating composition according to any one of <1> to <4>, which is for overprinting of an electrophotographic printed material,
<6> Overprint having an overprint layer obtained by photocuring the photocurable coating composition according to any one of <1> to <5> on a printed material,
<7> The overprint according to <6>, wherein the overprint layer has a thickness of 1 to 10 μm.
<8> The overprint according to <6> or <7>, wherein the printed material is an electrophotographic printed material,
<9> A step of printing on a printing substrate to obtain a printed material, a step of applying the photocurable coating composition according to any one of <1> to <5> on the printed material, and the photocuring A method for producing an overprint comprising a step of photocuring a functional coating composition,
<10> The method for producing an overprint according to <9>, wherein the printed material is an electrophotographic printed material.

  According to the present invention, surface smoothness, non-tackiness (surface tackiness suppression), and a photocurable coating composition excellent in odor suppression, an overprint obtained by applying and curing the photocurable coating composition, In addition, an overprint manufacturing method could be provided.

The photocurable coating composition of the present invention includes an onium salt containing a divalent or higher anion and a polymerizable compound.
Hereinafter, the present invention will be described in detail.

<Photocurable coating composition>
In the case of a toner-based image such as an electrophotographic method, when a feather oil layer is present on the image surface, the printed surface is hydrophobic and the surface energy is low, so that the curability, surface smoothness, strength, It is difficult to obtain a photocurable coating composition that satisfies all of storage stability and the like.
In addition, when overprint coating is applied on toner-based image information to treat it as an alternative to silver salt photographic prints, the odor and safety of the product is one of the important qualities for the general consumer to obtain directly. Become one.
The cause of odor generation is the remaining of volatile compounds such as polymerizable monomers (uncured monomer) and polymerization that is not incorporated into the cured film because it does not copolymerize with the curable composition. Examples include decomposition products of initiators.
Regarding the reduction of odor caused by polymerizable monomers, the use of low-volatile solid monomers and high molecular weight liquid monomers can be considered, but the surface smoothness decreases due to the increase in the viscosity of the polymerizable composition, and the printed surface There is a problem that streaks occur.

  By using a photocurable coating composition containing an onium salt having a divalent or higher valent anion as a counter ion, the present inventor can achieve surface smoothness, non-tackiness (surface tackiness suppression), and odor suppression. It has been found that an excellent overprint can be provided.

The photocurable coating composition of the present invention preferably has substantially no absorption in the visible range. “Substantially no absorption in the visible region” means that there is no absorption in the visible region of 400 to 700 nm, or there is absorption in the visible region only to the extent that there is no problem as a photocurable coating composition. It means not. Specifically, it means that the 5 μm optical path length transmittance of the coating composition is 70% or more, preferably 80% or more in the wavelength range of 400 to 700 nm.
The photocurable coating composition of the present invention can be suitably used for overprinting, and can be particularly suitably used for overprinting of electrophotographic prints.
The photocurable coating composition of the present invention is excellent in non-tackiness and surface smoothness, glossy and glossy even when an overprint layer is formed on an electrophotographic print having an image portion having a thickness equivalent to the toner. It gives a certain overprint and can visually give an impression close to that of a conventional silver halide photographic print.
In addition, the photocurable coating composition of the present invention is excellent in non-tackiness and surface smoothness, gloss, gloss, and flexibility with little warpage, even for a toner image having a feather oil layer on the image surface. Image prints that are rich in color and can provide an overprint that is visually similar to a silver halide photographic print.

<Onium salt containing a divalent or higher anion>
The photocurable coating composition of the present invention (hereinafter also simply referred to as “coating composition”) contains an onium salt containing a divalent or higher anion (hereinafter also simply referred to as “multivalent anion onium salt”). To do.

In the present invention, examples of the polyvalent anion onium salt include known diazonium salts, iodonium salts, sulfonium salts, ammonium salts, pyridinium salts, and azinium salts. Preferred onium ions include sulfonium ions, iodonium ions, diazonium ions. , Azinium ions, ammonium ions, and the like.
Specific examples of the polyvalent anion onium salt that can be suitably used include sulfonium salts, iodonium salts, and diazonium salts represented by the formulas (1) to (4), and more preferably from the viewpoint of stability. Triarylsulfonium salt or diaryliodonium salt.

In formula (1), Ar ¹¹ and Ar ¹² each independently represent an aryl group having 20 or less carbon atoms, which may have a substituent. Preferred substituents when this aryl group has a substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or 12 or less carbon atoms. Of the aryloxy group.
Z ¹¹ⁿ⁻ represents an n-valent counter anion described in detail below.
n represents an integer of 2 or more, and is preferably an integer of 2 to 4. The n iodonium ions may be the same or different.

In formula (2), Ar ²¹ represents an aryl group having 20 or less carbon atoms which may have a substituent. Preferred examples of the substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an aryloxy group having 12 or less carbon atoms, and 12 or less carbon atoms. Examples thereof include an alkylamino group, a dialkylamino group having 12 or less carbon atoms, an arylamino group having 12 or less carbon atoms, or a diarylamino group having 12 or less carbon atoms.
Z ^21n- represents a counter anion having the same ^meaning as Z ^11n- . The n diazonium ions may be the same or different.

In the formula (3), R ³¹ , R ³² and R ³³ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferably, all of R ³¹ , R ³² and R ³³ are aryl groups, and each may have a substituent. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms.
Z ^31n- represents a counter anion having the same ^meaning as Z ^11n- . The n sulfonium ions may be the same or different.

Ar ¹¹ and Ar ¹² in the formula (4) has the same meaning as Ar ¹¹ and Ar ¹² in the formula ^{(1), R 31, R} 32 and R ³³ in formula (4) is, R ³¹ in the formula (3), R ³² and R ³³ as synonymous.
l and m each represent an integer of 1 or more and satisfy l + m = n. n represents an integer of 2 or more, and is preferably an integer of 2 to 4.
Z ^41n- represents a counter anion having the same ^meaning as Z ^11n- . Further, when l is an integer of 2 or more, l iodonium ions may be the same or different, and when m is an integer of 2 or more, m sulfonium ions may be the same or different.

In the present invention, the divalent or higher anion Z ⁿ⁻ introduced as a counter ion to the polyvalent anion onium salt is not particularly limited as long as it has two or more anion sites in one molecule, and two or more The anion sites may be the same or different.
The polyvalent anion Z ⁿ⁻ is preferably divalent or higher and hexavalent or lower, more preferably a divalent, trivalent, or tetravalent anion, and further preferably a divalent anion in terms of synthesis. is there.

Examples of the anion moiety contained in the polyvalent anion Z ^n- include carboxylic acid, sulfonic acid, phosphonic acid, phenol, R ¹ —SO ₂ —NH—R ² , wherein R ¹ and R ² are monovalent non-valent A conjugated base of a carboxylic acid or a sulfonic acid from the viewpoint of stability and reactivity.
Examples of preferable divalent, trivalent, and tetravalent anions Zn ⁿ⁻ that can be applied to the present invention will be described below, but the present invention is not limited thereto.

  As the counter cation of these divalent, trivalent, and tetravalent anions, each onium ion described above is applied, but the same onium ion or a plurality of different onium ions may be applied. . Moreover, you may mix and use the polyvalent anion onium salt which has onium ion different from the same onium ion. Examples of preferable divalent, trivalent, and tetravalent polyvalent anion onium salts that can be applied to the present invention are shown below, but the present invention is not limited thereto.

  The following exemplified compounds (SA-1) to (SD-8) are examples of sulfonium salt compounds having a divalent anion and the same onium ion, and the exemplified compounds (SE-1) to (SG-6) are It is an example of a sulfonium salt compound having divalent anions and onium ions different from each other, and exemplary compounds (SH-1) to (SH-3) are trivalent anions and sulfonium salt compounds having the same onium ion. Example compounds (SI-1) and (SI-2) are examples of a sulfonium salt compound having a tetravalent anion and the same onium ion.

  The following exemplary compounds (IA-1) to (IF-8) are examples of iodonium salt compounds having a divalent anion and the same cation, and exemplary compounds (IG-1) to (IH-7) are 2 Example compounds (IJ-1) to (IJ-3) are examples of iodonium salt compounds having a trivalent anion, and are exemplified compounds (IK). -1) and (IK-2) are examples of iodonium salt compounds having a tetravalent anion.

  The following exemplary compounds (ISA-1) to (ISB-6) are examples of onium salt compounds having a divalent anion structure and sulfonium and iodonium as the cation structure.

  Among them, SA-1, SA-3, SA-13, SB-4, SC-1, SC-4, SC-5, SD-5, SF-2, SH-2, IA-1, IA-7, IB-4, IB-14, IB-15, IE-6, IF-7, IJ-2 and ISA-4 are preferred.

Below, the typical synthesis example of a polyvalent anion onium salt is shown.
[Synthesis Example 1: Synthesis of Multivalent Anion Onium Salt Illustrative Compound (SA-3)]
Diphenyl sulfoxide (50.9 g) was dissolved in benzene (800 ml), and aluminum chloride (200 g) was added thereto, followed by refluxing for 24 hours. The reaction solution was slowly poured into 2 L of water under ice cooling, 400 ml of concentrated hydrochloric acid was added thereto, and the mixture was heated at 70 ° C. for 10 minutes. This aqueous solution was washed with 500 ml of ethyl acetate and filtered, and then 200 g of ammonium iodide dissolved in 400 ml of water was added.
The precipitated powder was collected by filtration, washed with water, washed with ethyl acetate and dried to obtain 70 g of triphenylsulfonium iodide. 30.5 g of triphenylsulfonium iodide was dissolved in 1,000 ml of methanol, and 19.1 g of silver oxide was added to this solution, followed by stirring at room temperature for 4 hours. The solution was filtered and 3.2 g oxalic acid was added to it. The reaction solution was concentrated, and the concentrated solution was washed with ethyl acetate and hexane, and vacuum dried to obtain Exemplified Compound (SA-3) as a sulfonium salt in a yield of 91%.

[Synthesis Example 2: Synthesis of Multivalent Anion Onium Salt Illustrative Compound (IB-14)]
60 g of t-amylbenzene, 39.5 g of potassium iodate, 81 g of acetic anhydride and 170 ml of dichloromethane were mixed, and 66.8 g of concentrated sulfuric acid was slowly added dropwise thereto under ice cooling. The mixture was stirred for 2 hours under ice-cooling and then at room temperature for 10 hours. To the reaction solution stirred at room temperature for 10 hours, 500 ml of water was added under ice cooling, and components dissolved in the reaction were extracted with dichloromethane. The organic tank made of dichloromethane was washed with an aqueous sodium hydrogen carbonate solution and then with water. After washing, the organic phase was concentrated to obtain di (4-t-amylphenyl) iodonium sulfate. This sulfate was added to an aqueous solution of excess potassium iodide. Dichloromethane was extracted with this aqueous solution, washed with water, and the organic phase was concentrated to obtain di (4-t-amylphenyl) iodonium iodide. 75 g was obtained.
42.2 g of di (4-t-amylphenyl) iodonium iodide obtained above was dissolved in 2,000 ml of methanol, 19.1 g of silver oxide was added to this solution, and the mixture was stirred at room temperature for 4 hours. The solution was filtered, and 12 g of 1,3-benzenedisulfonic acid dipotassium salt was added thereto. The reaction solution was concentrated, the concentrated solution was washed with ethyl acetate and hexane, and vacuum dried to obtain Exemplified Compound (IB-14) which is an iodonium salt in a yield of 85%.

  Other sulfonium salts and iodonium salts can be synthesized in the same manner. As another method for obtaining iodonium iodide, Bull. Chem. Soc. Jpn 70, 219-224 (1997), Bull. Chem. Soc. Jpn 70, 1665-1669 (1997), Bull. Chem. Soc. Jpn 70, 115-120 (1999), J. MoI. Amer. Chem. Soc; 82; 1960, 725-731, J. MoI. Amer. Chem. Soc; 81; 1959, 342-346. Other methods for obtaining sulfonium iodide are described in J. Org. Amer. Chem. Soc; 91; 1969; 145-150, and the like can be used.

The preferable addition amount of these polyvalent anion onium salts is 0.1 to 40% by weight, more preferably 1 to 30% by weight, and still more preferably 5 to 20% by weight in the total solid content of the photocurable coating composition. It is a range.
If it is within the above numerical range, the photocurable coating composition is sufficiently cured and is excellent in non-tackiness (suppression of surface stickiness). Moreover, the viscosity of a photocurable coating composition is suitable, and the overprint layer excellent in surface smoothness is obtained.
Moreover, only 1 type may be used for polyvalent anion onium salt, and 2 or more types may be used together.

In the present invention, a compound that initiates and accelerates the polymerization of a known compound having a polymerizable group by generating a radical by thermal energy in addition to the polyvalent anion onium salt as a polymerization initiator (polymerization initiator) Can be used in combination as long as the effects of the present invention are not impaired. As such a polymerization initiator, a known thermal polymerization initiator or a compound having a bond with a small bond dissociation energy can be selected and used. For example, a compound having the onium salt structure and a counter anion is used. Monovalent ones can be preferably used.
When an onium salt having a general monovalent anion is used in the present invention, the addition amount is preferably 0 to 30% by weight, more preferably the total amount of the polymerization initiator containing a polyvalent anion onium salt. It is in the range of 0 to 15% by weight.
The polyvalent anion onium salt used in the present invention preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less. Thus, a coating composition with high transparency can be obtained by setting the absorption wavelength in the ultraviolet region.

<Polymerizable compound>
The photocurable coating composition of the present invention contains a polymerizable compound.
As the polymerizable compound, a radical polymerizable compound can be used, and a cationic polymerizable compound can also be used.

<Radically polymerizable compound>
In the present invention, the radical polymerizable compound is preferably a compound having an ethylenically unsaturated group.
The radical polymerizable compound in the present invention may be any compound as long as it has at least one ethylenically unsaturated group, and includes compounds having chemical forms such as monomers, oligomers, and polymers.
Only one type of radically polymerizable compound may be used, or two or more types thereof may be used in combination at an arbitrary ratio in order to improve target properties. From the viewpoint of controlling performance such as reactivity and physical properties, it is preferable to use two or more kinds of radically polymerizable compounds in combination.

  Examples of radically polymerizable compounds include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and other unsaturated carboxylic acids and salts thereof, anhydrides having ethylenically unsaturated groups, acrylonitrile, styrene Furthermore, radically polymerizable compounds such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides and unsaturated urethanes can be mentioned.

  Specifically, methyl acrylate, ethyl acrylate, n-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl Acrylate, phenoxyethyl acrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, dicyclopentenyloxyethyl acrylate, bis (4-acryloxypolyethoxyphenyl) propane, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate , Ethylene glycol diacrylate, diethylene glycol diacrylate, Liethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, caprolactone-modified dipentaerythritol hexaacrylate , Trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, N-methylol acrylamide, diacetone acrylamide, epoxy acrylate and other acrylic acid derivatives, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, hexyl meta Relate, 2-ethylhexyl methacrylate, lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, phenoxyethyl methacrylate, dicyclopentenyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenyloxyethyl methacrylate, dimethylaminomethyl methacrylate, 1,6-hexanediol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimeta Methacryl derivatives such as acrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, N-vinyl compounds such as N-vinylpyrrolidone and N-vinylcaprolactam, allyl glycidyl ether, diallyl phthalate, triallyl trimelli Derivatives of allyl compounds such as tate, etc., more specifically, Shinzo Yamashita, “Crosslinker Handbook” (1981, Taiseisha Co., Ltd.); (Ingredients) ”(1985, Polymer Press Association); Radtech Study Group,“ Application and Market of UV / EB Curing Technology ”, p. 79, (1989, CMC Publishing Co., Ltd.); Eiichiro Takiyama, Commercially available products described in “Polyester Resin Handbook” (1988, Nikkan Kogyo Shimbun Co., Ltd.) or other radios known in the industry Le polymerizable or crosslinkable monomers, may be used an oligomer, and polymer.

  Examples of the radical polymerizable compound include those disclosed in JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, JP-A-9-134011, and the like. Photocurable polymeric compound materials used for the described photopolymerizable compositions are known and can also be applied to the coating compositions of the present invention.

Furthermore, it is also preferable to use a vinyl ether compound as the radical polymerizable compound. Suitable vinyl ether compounds include, for example, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, and cyclohexanedimethanol. Di- or trivinyl ether compounds such as divinyl ether and trimethylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl Monovinyl ether compounds such as ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, octadecyl vinyl ether, ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, hydroxyethyl monovinyl ether, hydroxynonyl monovinyl ether, etc. Is mentioned.
Among these vinyl ether compounds, a divinyl ether compound or a trivinyl ether compound is preferable and a divinyl ether compound is more preferable from the viewpoint of curability, adhesion, and surface hardness. A vinyl ether compound may be used individually by 1 type, and may be used in combination of 2 or more type as appropriate.

  Examples of other polymerizable compounds that can be used in the present invention include (meth) acrylic monomers or prepolymers, epoxy monomers or prepolymers, or (meth) acrylic acid esters such as urethane monomers or prepolymers (hereinafter referred to as “polymeric esters”). As appropriate, it is also referred to as “(meth) acrylate compound”). More preferably, they are the following compounds. In addition, “(meth) acrylate” represents both “acrylate” and “methacrylate”.

  That is, 2-ethylhexyl diglycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, 2-acryloyl Roxyethylphthalic acid, methoxypolyethylene glycol (meth) acrylate, tetramethylolmethane tri (meth) acrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, dimethylol tricyclodecane di (meth) acrylate, ethoxylated phenyl (Meth) acrylate, 2-acryloyloxyethyl succinic acid, nonylphenol ethylene oxide (EO) adduct (meth) acrylate, modified glycerin tri (meth) acrylate, bis Enol A diglycidyl ether acrylic acid adduct, modified bisphenol A di (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, 2-acryloyloxyethylhexahydrophthalic acid, propylene oxide (PO) adduct di ( (Meth) acrylate, bisphenol A EO adduct di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate tolylene diisocyanate urethane prepolymer, lactone-modified flexible (meth) acrylate, Butoxyethyl (meth) acrylate, propylene glycol diglycidyl ether acrylic acid adduct, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate Urethane prepolymer, 2-hydroxyethyl (meth) acrylate, methoxydipropylene glycol (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate urethane prepolymer, stearyl (Meth) acrylate, isoamyl (meth) acrylate, isomyristyl (meth) acrylate, isostearyl (meth) acrylate, lactone-modified (meth) acrylate, and the like.

  The (meth) acrylate compounds listed here have high reactivity, low viscosity, and excellent adhesion to a printing substrate.

In the present invention, in order to further improve non-tackiness (surface tackiness) and transparency, it is preferable to include a polyfunctional (meth) acrylate compound among the above-mentioned radical polymerizable compounds.
As the polyfunctional (meth) acrylate, bisphenol A epoxy di (meth) acrylate and tripropylene glycol di (meth) acrylate can be particularly preferably exemplified.
Moreover, when using polyfunctional ethylenically unsaturated compounds, such as polyfunctional (meth) acrylate, as content of a polyfunctional ethylenically unsaturated compound, it is 5 to 80 weight% with respect to the total weight of a coating composition. It is preferable that it is 40 to 70% by weight. Within the above range, non-tackiness is excellent.

  In the present invention, depending on various purposes, a combination of a radical polymerizable compound and a radical photopolymerization initiator, a combination of a cationic polymerizable compound and a cationic photopolymerization initiator, or a combination of these radicals. -It is good also as a hybrid type coating composition of a cation.

<Cationically polymerizable compound>
The cationically polymerizable compound in the present invention is not particularly limited as long as it is a compound that generates and cures a cationic polymerization reaction by applying some energy, and can be used regardless of the type of monomer, oligomer, or polymer. Various known cationically polymerizable monomers known as photocationically polymerizable monomers that cause a polymerization reaction with an initiation species generated from the aforementioned cationic polymerization initiator can be used. The cationic polymerizable compound may be a monofunctional compound or a polyfunctional compound.

As the cationically polymerizable compound in the present invention, an oxetane ring-containing compound and an oxirane ring-containing compound are preferable from the viewpoint of curability and scratch resistance, and an embodiment containing both the oxetane ring-containing compound and the oxirane ring-containing compound is preferable. More preferred.
Here, in this specification, an oxirane ring-containing compound (hereinafter sometimes referred to as “oxirane compound” as appropriate) is a compound containing at least one oxirane ring (oxiranyl group, epoxy group) in the molecule. Specifically, it can be appropriately selected from those usually used as an epoxy resin, and examples thereof include conventionally known aromatic epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins. Any of a monomer, an oligomer, and a polymer may be sufficient. An oxetane ring-containing compound (hereinafter sometimes referred to as “oxetane compound” as appropriate) is a compound containing at least one oxetane ring (oxetanyl group) in the molecule.

Hereinafter, the cationically polymerizable compound applicable to the present invention will be described in detail.
Examples of the cationic polymerizable monomer include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and 2001-2001. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in each publication such as No. 220526.

  Examples of monofunctional epoxy compounds that can be used in the present invention include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, and 1,2-butylene. Oxide, 1,3-butadiene monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide , 3-vinylcyclohexene oxide and the like.

Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol. S diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxy 2- (3,4-epoxycyclohexyl) -7,8-epoxy-1,3-dioxaspiro [5.5] undecane, bis (3,4-epoxycyclohexyl) Rumethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, Reserin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,13-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-diepoxyoctane 1,2,5,6-diepoxycyclooctane and the like.
Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  Examples of monofunctional vinyl ethers that can be used in the present invention include, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl. Vinyl ether, cyclohexyl methyl vinyl ether, 4-methyl cyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxy Ethyl vinyl ether, methoxypoly Tylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether Chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether, and the like.

Examples of the polyfunctional vinyl ether include, for example, ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, and bisphenol F. Divinyl ethers such as alkylene oxide divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide addition Examples thereof include polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.
As the vinyl ether compound, a di- or trivinyl ether compound is preferable from the viewpoints of curability, adhesion to a recording medium such as a printing substrate or printed matter, and surface hardness of the formed image, and a divinyl ether compound is particularly preferable.

  As the oxetane compound in the present invention, known oxetane compounds as described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217 can be arbitrarily selected and used.

  As the oxetane compound that can be used in the present invention, a compound having 1 to 4 oxetane rings in its structure is preferable. By using such a compound, it becomes easy to maintain the viscosity of the photocurable coating composition in a favorable range of handling properties, and the photocurable coating composition after curing, the printing substrate, High adhesion to a recording medium such as a printed material can be obtained.

  Examples of monofunctional oxetane compounds that can be used in the present invention include, for example, 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanyl). Methoxy) methylbenzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl [benzene, 4-methoxy- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3-Ethyl-3-oxetanylmethoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3 -Ethyl-3-oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl) -3-oxetanylmethyl) ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ) Ether, 2-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3) Oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether Pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, and the like.

  Examples of polyfunctional oxetane compounds include, for example, 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene) ) Bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether , Triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3 Ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3 -Ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl- 3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3- Til-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentane Kiss (3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, ethylene oxide (EO) modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, Propylene oxide (PO) modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, EO modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) Examples thereof include polyfunctional oxetanes such as ether, PO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, and EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl) ether.

Such oxetane compounds are described in detail in the above-mentioned JP-A No. 2003-341217, paragraphs 0021 to 0084, and the compounds described herein can be suitably used in the present invention.
Among the oxetane compounds that can be used in the present invention, it is preferable to use a compound having 1 to 2 oxetane rings.
In the present invention, these cationically polymerizable compounds may be used alone or in combination of two or more.

In view of curability and surface smoothness, the content of the polymerizable compound in the photocurable coating composition of the present invention is preferably in the range of 10 to 97% by weight with respect to the total weight of the coating composition. 30 to 95% by weight is more preferable, and 50 to 90% by weight is more preferable.
Moreover, a polymeric compound may be used by 1 type and may use 2 or more types together.

<Photopolymerization initiator>
The coating composition of the present invention may contain a photopolymerization initiator.
A known photopolymerization initiator can be used as the photopolymerization initiator. In the present invention, it is preferable to use a radical photopolymerization initiator.
The photopolymerization initiator used in the coating composition of the present invention is a compound that generates a polymerization initiating species by absorbing external energy due to actinic radiation. Examples of the active radiation include γ rays, β rays, electron beams, ultraviolet rays, visible rays, and infrared rays. Although the wavelength to be used is not specifically limited, Preferably it is a 200-500 nm wavelength range, More preferably, it is a 200-450 nm wavelength range.

Examples of radical photopolymerization initiators that can be preferably used in the present invention include (a) aromatic ketones, (b) acylphosphine compounds, (c) aromatic onium salt compounds, (d) organic peroxides, (e) thios. Compound, (f) hexaarylbiimidazole compound, (g) ketoxime ester compound, (h) borate compound, (i) azinium compound, (j) metallocene compound, (k) active ester compound, (l) carbon halogen bond And (m) alkylamine compounds and the like.
A preferable photopolymerization initiator from the viewpoint of transparency is preferably a compound having an absorbance at a wavelength of 400 nm of 0.3 or less when the photopolymerization initiator is formed to a thickness of 3 g / cm ^2. More preferably, the compound is 2 or less, and further preferably 0.1 or less.
Among these, preferable photopolymerization initiators include (a) aromatic ketones, (b) acylphosphine compounds, and (c) aromatic onium salt compounds.
The photopolymerization initiator in the present invention may be used alone or in combination.

The content of the photopolymerization initiator in the present invention is preferably 0.01 to 35% by weight, more preferably 0.1 to 30% by weight, based on the total amount of the polymerizable compound. More preferably, it is 5 to 30% by weight.
Moreover, when using a sensitizer described later, the photopolymerization initiator is preferably 200: 1 to 1: 200 in a weight ratio of photopolymerization initiator: sensitizer with respect to the sensitizer. It is more preferably 50: 1 to 1:50, and further preferably 20: 1 to 1: 5.

In the present invention, as the cationic photopolymerization initiator (photoacid generator) used in combination with the above cationic polymerizable compound, for example, a chemical amplification type photoresist or a compound used for photocationic polymerization is used (for example, organic (Electronic Materials Research Group, “Organic Materials for Imaging”, Bunshin Publishing (1993), pages 187 to 192).
Examples of the cationic photopolymerization initiator suitable for the present invention are listed below.
That is, first, B (C ₆ F ₅ ) ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF of aromatic onium compounds such as diazonium, ammonium, iodonium, sulfonium, phosphonium, excluding the polyvalent anion onium salt. ₆ ^-, CF ₃ SO ₃ ^- salts. Secondly, sulfonated products that generate sulfonic acid can be mentioned. Thirdly, a halide that generates hydrogen halide by light can also be used. Fourthly, iron arene complexes can be mentioned.
The cationic photopolymerization initiator as described above may be used alone or in combination of two or more.

<Sensitizer>
A sensitizer can be added to the coating composition of the present invention in order to promote decomposition of the photopolymerization initiator by irradiation with active radiation.
The sensitizer absorbs specific actinic radiation and enters an electronically excited state. The sensitizer in an electronically excited state comes into contact with the photopolymerization initiator to cause actions such as electron transfer, energy transfer, and heat generation, thereby causing a chemical change of the photopolymerization initiator, that is, decomposition, radical, acid. Or it promotes the production of bases.
In addition, the sensitizer that can be used in the present invention is preferably a compound or an amount having a small influence of coloring or the like when the coating composition of the present invention is used for overprinting.
The content of the sensitizer in the present invention is preferably 0.001 to 5% by weight, more preferably 0.01 to 3% by weight, based on the total weight of the coating composition. With this addition amount, curability is improved and the influence of coloring is small.

The sensitizer may be a compound corresponding to the wavelength of actinic radiation that generates an initiating species in the photopolymerization initiator to be used, but considering that it is used for a curing reaction of a general coating composition. Examples of preferred sensitizers include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.
Polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine), merocyanines (Eg, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squalium (eg, Squalium), coumarins (for example, 7-diethylamino-4-methylcoumarin), benzophenones (for example, benzophenone) and the like.

  More preferable examples of the sensitizer include compounds represented by the following formulas (II) to (VI).

In the formula (II), A ¹ represents a sulfur atom or NR ⁵⁰ , R ⁵⁰ represents an alkyl group or an aryl group, and L ² represents a non-nuclear group that forms a basic nucleus together with the adjacent A ¹ and the adjacent carbon atom. R ⁵¹ and R ⁵² each independently represent a hydrogen atom or a monovalent non-metal atomic group, and R ⁵¹ and R ⁵² may be bonded to each other to form an acidic nucleus. W represents an oxygen atom or a sulfur atom.

In formula (III), Ar ¹ and Ar ² each independently represent an aryl group, and are linked via a bond with —L ³ —. Here, L ³ represents —O— or —S—. W is synonymous with that shown in Formula (II).

In the formula (IV), A ² represents a sulfur atom or NR ⁵⁹ , L ⁴ represents a nonmetallic atomic group that forms a basic nucleus in combination with adjacent A ² and a carbon atom, R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ and R ⁵⁸ each independently represent a monovalent nonmetallic atomic group, and R ⁵⁹ represents an alkyl group or an aryl group.

In formula (V), A ³ and A ⁴ each independently represent —S— or —NR ⁶² — or —NR ⁶³ —, wherein R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted alkyl group, substituted or Represents an unsubstituted aryl group, and L ⁵ and L ⁶ each independently represent a nonmetallic atomic group that forms a basic nucleus together with adjacent A ³ , A ^4, and adjacent carbon atoms, R ⁶⁰ , R Each ⁶¹ is independently a hydrogen atom or a monovalent nonmetallic atomic group, or can be bonded to each other to form an aliphatic or aromatic ring.

In the formula (VI), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent, and A ⁵ represents an oxygen atom, a sulfur atom or NR ⁶⁷ . R ⁶⁴ , R ⁶⁵ and R ⁶⁷ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ are each an aliphatic or aromatic ring. Can be combined to form

  Preferable specific examples of the compounds represented by formulas (II) to (VI) include those shown below. In the specific examples below, Ph represents a phenyl group, and Me represents a methyl group.

<Co-sensitizer>
The coating composition of the present invention can also contain a co-sensitizer.
In the present invention, the co-sensitizer has functions such as further improving the sensitivity of the sensitizer to actinic radiation or suppressing polymerization inhibition of the polymerizable compound by oxygen.
Examples of such cosensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Society”, Vol. 10, 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59-138205. And JP-A-60-84305, JP-A-62-18537, JP-A-64-33104, Research Disclosure 33825, and the like.
Specific examples include triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

Other examples of co-sensitizers include thiols and sulfides such as thiol compounds described in JP-A-53-702, JP-A-55-500806, and JP-A-5-142277, Examples thereof include disulfide compounds described in JP-A-56-75643.
Specific examples include 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercaptonaphthalene and the like.

  Other examples include amino acid compounds (for example, N-phenylglycine), organometallic compounds described in Japanese Patent Publication No. 48-42965 (for example, tributyltin acetate), and hydrogen described in Japanese Patent Publication No. 55-34414. Donors, sulfur compounds described in JP-A-6-308727 (for example, trithiane), phosphorus compounds described in JP-A-6-250387 (for example, diethyl phosphite), and JP-A-8-54735 Examples thereof include Si—H and Ge—H compounds.

<Surfactant>
The coating composition of the present invention may contain a surfactant.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. Further, an organic fluoro compound or a polysiloxane compound may be used as the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compounds include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826. Among these, as the surfactant, a polydimethylsiloxane compound can be preferably exemplified.
These surfactants may be used alone or in combination of two or more.

<Other ingredients>
If necessary, other components can be added to the coating composition of the present invention. Examples of other components include a polymerization inhibitor, a solvent, inorganic particles, and organic particles.
A polymerization inhibitor may be added from the viewpoint of enhancing the storage stability. The polymerization inhibitor is preferably added in an amount of 200 to 20,000 ppm based on the total amount of the coating composition of the present invention.
Examples of the polymerization inhibitor include hydroquinone, benzoquinone, p-methoxyphenol, TEMPO, TEMPOL, and cuperon Al.
Inorganic particles such as Aerosil (Degussa silicon dioxide particles) and organic particles such as crosslinked polymethylmethacrylate (PMMA) are added to the coating composition of the present invention to intentionally reduce the surface gloss. A print layer or overprint can be formed.

In view of the fact that the coating composition of the present invention is a radiation curable coating composition, it is preferable that the coating composition of the present invention does not contain a solvent so that it can react quickly and be cured after application. However, a predetermined solvent can be included as long as the curing rate of the coating composition is not affected.
In the present invention, an organic solvent can be used as the solvent, and it is preferable that water is not substantially added from the viewpoint of curing speed. An organic solvent can be added to improve adhesion to a printing substrate (image receiving substrate such as paper).
When using an organic solvent, the amount is preferably as small as possible, preferably 0.1 to 5% by weight, and preferably 0.1 to 3% by weight, based on the total weight of the coating composition of the present invention. Is more preferable.

In addition, known compounds can be added to the coating composition of the present invention as necessary.
For example, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, waxes, and the like can be appropriately selected and added.

  Moreover, in order to improve the adhesiveness to printing base materials, such as polyolefin and a polyethylene terephthalate (PET), it is also preferable to contain the tackifier (tackifier) which does not inhibit superposition | polymerization. Specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, pages 5 to 6 (for example, (meth) acrylic acid and an alcohol having an alkyl group having 1 to 20 carbon atoms). Esters, copolymers of (meth) acrylic acid and C3-14 alicyclic alcohols, copolymers of (meth) acrylic acid and C6-14 aromatic alcohols), ethylenic And low molecular weight tackifying resins having an unsaturated group.

<Properties of photocurable coating composition>
The preferred physical properties of the photocurable coating composition of the present invention will be described.
When used as a photocurable coating composition, the viscosity at 25 to 30 ° C. is preferably 5 to 100 mPa · s, more preferably 7 to 75 mPa · s in consideration of applicability.
It is preferable that the composition ratio of the photocurable coating composition of the present invention is appropriately adjusted so that the viscosity is in the above range.
By setting the viscosity at 25 ° C. to 30 ° C. to the above value, an overprint having an overprint layer excellent in non-tackiness (no surface stickiness) and excellent in surface smoothness can be obtained.
The surface tension of the photocurable coating composition of the present invention is preferably 16 to 40 mN / m, and more preferably 18 to 35 mN / m.

<Overprint and manufacturing method thereof>
The overprint of the present invention has an overprint layer obtained by photocuring the coating composition of the present invention on a printed material.
The overprint forms at least one overprint layer on the surface of a printed material obtained by a printing method such as electrophotographic printing, inkjet printing, screen printing, flexographic printing, planographic printing, intaglio printing, or relief printing. It is what.
The overprint layer in the overprint of the present invention may be formed on a part of the printed matter or on the entire surface of the printed matter. In the case of a double-sided printed matter, it is formed on the entire surface of both sides of the printing substrate. It is preferable. Needless to say, the overprint layer may be formed in a non-printed portion of the printed material.
The printed material used for the overprint of the present invention is preferably an electrophotographic printed material. By forming an overprint layer, which is a cured layer of the coating composition of the present invention, on an electrophotographic printed matter, it is excellent in non-tackiness, surface smoothness and gloss, and visually similar to a silver salt photographic print. Can be obtained.
Further, since the overprint of the present invention is excellent in non-tackiness, even if a plurality of overprints of the present invention are stacked and stored for a long period of time, the overprints do not stick to each other and are excellent in storability.
The thickness of the overprint layer in the overprint of the present invention is preferably 1 to 10 μm, and more preferably 3 to 6 μm.

The overprint production method of the present invention includes a step of printing on a printing substrate to obtain a printed material, a step of applying the photocurable coating composition of the present invention on the printed material, and the photocurable coating composition. It is preferable to include a step of photocuring.
The overprint manufacturing method of the present invention includes a step of generating an electrostatic latent image on a latent image carrier, a step of developing the electrostatic latent image with toner, and printing the developed electrostatic image. A step of transferring to a substrate to obtain an electrophotographic printed material, a step of applying the photocurable coating composition of the present invention on the electrophotographic printed material, and a step of photocuring the photocurable coating composition. It is more preferable.
The printing substrate is not particularly limited, and known materials can be used. However, image receiving paper is preferable, plain paper or coated paper is more preferable, and coated paper is further used. preferable. As the coated paper, a double-sided coated paper is preferable because a full color image can be printed on both sides beautifully. When the printing substrate is paper or double-side coated paper, the preferred basis weight is 20 to 200 g / m ² , and the more preferred basis weight is 40 to 160 g / m ² .

The method for developing an image in electrophotography is not particularly limited, and can be arbitrarily selected from methods known to those skilled in the art. For example, a cascade method, a touchdown method, a powder cloud method, a magnetic brush method, and the like can be given.
Examples of a method for transferring the developed image to the printing substrate include a method using a corotron or a bias roll.
A fixing step for fixing an image in the electrophotographic method can be performed by various appropriate methods. Examples thereof include flash fixing, heat fixing, pressure fixing, and vapor fixing.
The image forming method, apparatus, and system by electrophotography are not particularly limited, and known ones can be used. Specifically, it is as described in the following US patent specifications.
US Pat. No. 4,585,884, US Pat. No. 4,584,253, US Pat. No. 4,563,408, US Pat. No. 4,265,990, US Pat. US Pat. No. 6,180,308, US Pat. No. 6,212,347, US Pat. No. 6,187,499, US Pat. No. 5,966,570, US Pat. No. 5,627,002, US Pat. No. 5,366,840; US Pat. No. 5,346,795, US Pat. No. 5,223,368, and US Pat. 826, 147 specification.

In order to apply the photocurable coating composition, a commonly used liquid film coating device can be used. Specifically, roll coaters, rod coaters, blades, wire bars, dipping, air knives, curtain coaters, slide coaters, doctor knives, screen coaters, gravure coaters, offset gravure coaters, slot coaters, extrusion coaters, etc. It can be illustrated. These devices can be used in the same way as usual, but for example, direct and reverse roll coating, blanket coating, dampner coating, There are curtain coating, lithographic coating, screen coating, and gravure coating. In a preferred embodiment, the coating composition of the present invention is applied and cured using two or three roll coaters and a UV curing station.
Moreover, you may heat as needed at the time of application | coating and hardening of the coating composition of this invention.
Typical levels of coating weight of the coating composition of the present invention, a weight per unit area is preferably in the range of ^{1g / m 2 ~10g / m 2} , 3g / m 2 ~6g / m ² is more preferable.
The formation amount of the overprint layer in the overprint of the present invention, per unit area, it is preferably in the range of ^{1g / m 2 ~10g / m 2} , is 3g / m ² ~6g / m ² More preferred.

The energy source used to initiate the polymerization of the polymerizable compound contained in the coating composition of the present invention may be actinic, for example, radiation having a spectral ultraviolet or visible wavelength. ) (Active radiation). Polymerization by irradiation with actinic radiation is excellent in initiating polymerization and adjusting the polymerization rate.
Suitable actinic radiation irradiation sources include, for example, mercury lamps, xenon lamps, carbon arc lamps, tungsten filament lamps, lasers, sunlight, and the like.

  Under ultraviolet irradiation (UV light irradiation), irradiation with a medium pressure mercury lamp using a high-speed conveyor (preferably 20 to 70 m / min) is preferable, in which case UV light irradiation has a wavelength of 200 to 500 nm. And preferably for less than 1 second. More preferably, the speed of the high-speed conveyor is 15 to 35 m / min, and UV light having a wavelength of 200 to 450 nm is irradiated for 10 to 50 milliseconds (ms). The emission spectrum of the UV light source usually overlaps with the absorption spectrum of the UV polymerization initiator. Curing equipment used in some cases includes a reflector that collects and diffuses UV light, and a cooling system for removing heat generated by the UV light source. It is not limited.

<Properties of cured product obtained by curing photocurable coating composition>
The cured product obtained by curing the photocurable coating composition of the present invention by light irradiation (preferably ultraviolet irradiation (UV light irradiation)) preferably has substantially no absorption in the visible region. “Substantially no absorption in the visible range” means that there is no absorption in the visible range of 400 to 700 nm, or that there is no absorption in the visible range to the extent that there is no problem as a photocurable coating. Means. Specifically, it means that the 5 μm optical path length transmittance of the coating composition is 70% or more, preferably 80% or more in the wavelength range of 400 to 700 nm.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the embodiments in these examples.

[Example 1]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 1.
FA-513A (manufactured by Hitachi Chemical Co., Ltd.) 25% by weight
2-phenoxyethyl acrylate (Tokyo Chemical Industry Co., Ltd.) 25% by weight
N-vinylcaprolactam (Aldrich) 20% by weight
Hexyl acrylate 15% by weight
Compound (SA-1) 13% by weight
BYK-3510 (manufactured by BYK Chemie) 2% by weight

[Examples 2 to 10]
In Examples 2 to 10, photocurable overprint compositions 2 to 10 were obtained in the same manner as in Example 1 except that the compound (SA-1) of Example 1 was changed to the compounds described in Table 1. .

Example 11
The following components were stirred with a stirrer to obtain a photocurable overprint composition 11.
30% by weight of tripropylene glycol diacrylate (manufactured by Aldrich)
Lauryl acrylate (Tokyo Chemical Industry Co., Ltd.) 10% by weight
OTA-480 (CYTEC SURFACE SPECIAL TIES) 30% by weight
Hexyl acrylate 15% by weight
Compound (SA-1) 13% by weight
BYK-3510 (manufactured by BYK Chemie) 2% by weight

[Examples 12 to 20]
In Examples 12 to 20, photocurable overprint compositions 12 to 20 were obtained in the same manner as in Example 11 except that the compound (SA-1) of Example 11 was changed to the compounds described in Table 1. .

Example 21
The following components were stirred with a stirrer to obtain a photocurable overprint composition 21.
30% by weight of tripropylene glycol diacrylate (manufactured by Aldrich)
NK Ester A-TMPT (Shin Nakamura Chemical Co., Ltd.) 10% by weight
DPCA-60 (Nippon Kayaku Co., Ltd.) 10% by weight
Lauryl acrylate (Tokyo Chemical Industry Co., Ltd.) 20% by weight
Hexyl acrylate 15% by weight
Compound (SA-1) 13% by weight
Polydimethylsiloxane (Aldrich) 2% by weight

[Example 22]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 22.
3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UCB) 20% by weight
3,7-bis (3-oxetanyl) -5-oxanonane (OXT-221: manufactured by Toagosei Co., Ltd.) 45% by weight
3-ethyl-3-phenoxymethyloxetane (OXT-211: manufactured by Toagosei Co., Ltd.)
20% by weight
Compound (SA-1) 13% by weight
9,10-dibutoxyanthracene 2% by weight
Even when the photocurable overprint composition of Example 22 was used, a good coating was obtained.

[Comparative Example 1]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 1 for comparison.
FA-513A (Hitachi Chemical Industry Co., Ltd.) 25% by weight
2-phenoxyethyl acrylate (Tokyo Chemical Industry Co., Ltd.) 25% by weight
N-vinylcaprolactam (Aldrich) 20% by weight
Hexyl acrylate 15% by weight
Comparative compound HS 13% by weight
BYK-351 (manufactured by BYK Chemie) 2% by weight

[Comparative Example 2]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 2 for comparison.
FA-513A (manufactured by Hitachi Chemical Co., Ltd.) 25% by weight
2-phenoxyethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 25% by weight
N-vinylcaprolactam (Aldrich) 20% by weight
Hexyl acrylate 15% by weight
Comparative compound HI 13% by weight
BYK-3510 (manufactured by BYK Chemie) 2% by weight

[Comparative Example 3]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 3 for comparison.
FA-513A (manufactured by Hitachi Chemical Co., Ltd.) 25% by weight
2-phenoxyethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 25% by weight
N-vinylcaprolactam (Aldrich) 20% by weight
23% by weight of hexyl acrylate
Comparative compound HI 5% by weight
BYK-3510 (manufactured by BYK Chemie) 2% by weight

[Comparative Example 4]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 4 for comparison.
30% by weight of tripropylene glycol diacrylate (manufactured by Aldrich)
Lauryl acrylate (Tokyo Chemical Industry Co., Ltd.) 10% by weight
OTA-480 (CYTEC SURFACE SPECIAL TIES) 30% by weight
Hexyl acrylate 15% by weight
Comparative compound HS 13% by weight
BYK-3510 (manufactured by BYK Chemie) 2% by weight

[Comparative Example 5]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 5 for comparison.
30% by weight of tripropylene glycol diacrylate (manufactured by Aldrich)
Lauryl acrylate (Tokyo Chemical Industry Co., Ltd.) 10% by weight
OTA-480 (CYTEC SURFACE SPECIAL TIES) 30% by weight
Hexyl acrylate 15% by weight
Comparative compound HI 13% by weight
BYK-3510 (manufactured by BYK Chemie) 2% by weight

[Comparative Example 6]
The following components were stirred with a stirrer to obtain a photocurable overprint composition 6 for comparison.
30% by weight of tripropylene glycol diacrylate (Aldrich)
Lauryl acrylate (Tokyo Kasei) 10% by weight
OTA-480 (CYTEC SURFACE SPECIAL TIES) 30% by weight
23% by weight of hexyl acrylate
Comparative compound HI 5% by weight
BYK-3510 (manufactured by BYK Chemie) 2% by weight

[Comparative Example 7]
The following components were stirred with a stirrer to obtain a comparative photocurable overprint composition 7.
3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UCB) 20% by weight
3,7-bis (3-oxetanyl) -5-oxanonane (OXT-221: manufactured by Toagosei Co., Ltd.) 45% by weight
3-ethyl-3-phenoxymethyloxetane (OXT-211: manufactured by Toagosei Co., Ltd.)
20% by weight
Comparative compound HS 13% by weight
9,10-dibutoxyanthracene 2% by weight

<Performance evaluation>
Using the obtained photocurable overprint composition, the performance was evaluated by the following method. The results are shown in Table 1.

<Evaluation of surface smoothness (leveling property)>
For electrophotographic prints output to double-side coated paper with a digital printer (DC8000) manufactured by Fuji Xerox Co., Ltd., coated on one side with a film thickness of 5 g / m ² using a UV varnish coater (SG610V) manufactured by Shinano Kenshi Co., Ltd. This was visually evaluated for the occurrence of vertical stripes on the surface of the coated printed material. The evaluation criteria are shown below.
◎: No vertical stripes ○: A little vertical stripes remain ×: Remarkably vertical stripes are observed

<Non-tackiness (surface stickiness suppression) evaluation>
It is obtained by applying a bar coating on one side of the electrophotographic printed matter outputted on a double-side coated paper with a digital printer (DC8000) manufactured by Fuji Xerox Co., Ltd. so that the coating composition has a film thickness of 5 g / m ^2. The coated film was exposed to 120 mJ / cm ² at an illuminance of 1.0 W / cm ² using a UV lamp (LC8) manufactured by Hamamatsu Photonics Co., Ltd., to prepare an overprint sample. The non-tackiness after exposure was evaluated by touch. The evaluation criteria are shown below.
◎: No stickiness ○: Almost no stickiness ×: With stickiness

<Odor evaluation>
A varnish coater manufactured by Shinano Kenshi Co., Ltd. (SG610V) on one side of the electrophotographic printed material outputted on a double-side coated paper with a digital printer (DC8000) manufactured by Fuji Xerox Co., Ltd. so that the coating composition has a film thickness of 5 g / m ^2. ), The sensory evaluation was performed by smelling the odor and the odor level was evaluated according to the following criteria.

Evaluated by the following evaluation criteria (evaluation points) with 8 expert panelists.
Evaluation criteria (evaluation points):
5 (points): Eight out of eight people recognized the effect of reducing odor.
4 (points): 6 to 7 out of 8 people recognized the effect of reducing odor.
3 (points): 4 to 5 out of 8 people recognized the effect of reducing odor.
2 (points): 1 to 3 out of 8 people recognized the effect of reducing odor.
1 (point): No odor reduction effect was observed.
In addition, when an evaluation score is 4 points or more, it is thought that there is no problem in practical use.

Example 23
Twenty-two printed materials were produced by electrophotographic printing full color images of several frames each on both sides of an A4 size double-side coated paper (basis weight 100 g / m ² ). Each of the photocurable coating compositions prepared in 22 was applied in the same manner as in Example 1 so that the coating amount was 5 g / m ² , and then irradiated with ultraviolet rays to prepare overprints. When these were bound and used as a photo album together with the cover, a photo album with the same visibility as a silver halide photo print was obtained.

Example 24
A full color image including a menu photo and text were electrophotographic printed on both sides of 22 sheets of A3 size double side coated paper (basis weight 100 g / m ² ). The photocurable coating compositions prepared in Examples 1 to 22 were applied to both sides of these printed materials in the same manner as in Example 1 so that the coating amount was 5 g / m ^{2 on} one side. Thereafter, ultraviolet light was irradiated to prepare a double-sided overprint. When these were bound into a restaurant menu, a restaurant menu was obtained that had the same visibility as a silver halide photographic print.

Claims (10)

An onium salt containing a divalent or higher anion, and
A photocurable coating composition comprising a polymerizable compound.   The photocurable coating composition of claim 1 having substantially no absorption in the visible range.   The photocurable coating composition according to claim 1 or 2, wherein the onium salt is a sulfonium salt and / or an iodonium salt.   The photocurable coating composition according to any one of claims 1 to 3, which is used for overprinting.   The photocurable coating composition according to any one of claims 1 to 4, which is used for overprinting an electrophotographic printed material.   The overprint which has the overprint layer which photocured the photocurable coating composition of any one of Claims 1-5 on printed matter.   The overprint according to claim 6, wherein the overprint layer has a thickness of 1 to 10 μm.   The overprint according to claim 6 or 7, wherein the printed matter is an electrophotographic printed matter. Printing on a printing substrate to obtain a printed matter,
Applying the photocurable coating composition according to any one of claims 1 to 5 on the printed matter; and
A step of photocuring the photocurable coating composition.   The overprint manufacturing method according to claim 9, wherein the printed material is an electrophotographic printed material.