JP2009079125A - 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, and to provide an overprint and a manufacturing method for it excellent in surface smoothness and non-tacking properties by using the photocurable coating composition. <P>SOLUTION: The photocurable coating composition comprises (I) a fluorine-containing polymer having cyclic hydrocarbon radicals, (II) an ethylenic unsaturated compound, and (III) a photopolymerization initiator. The overprint and the manufacturing method of it produced by using the photocurable coating composition are provided. The photocurable coating composition can be suitably used as a photocurable coating composition for an overprint of an electrophotographic printed matter. <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 number of actinic radiation curable compositions that can be used for UV-curable printing inks, paints, and coatings have been developed and are now being popularized. However, it is difficult to obtain a photocurable composition that satisfies all of the curability, surface smoothness, strength, storage stability, and the like.
In particular, toner-based images such as electrophotography are more difficult to obtain the desired performance when a feather oil layer is present on the image surface.
In a conventional method for generating a toner-based image, such as electrophotography, an electrostatic charge is formed on the surface of the latent image carrier by uniformly charging the surface of the latent image carrier, for example, a photoreceptor. Let 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.

JP-A-11-70647 JP 2003-241414 A JP-A-61-210365 JP-A-2005-321882

  Problems to be solved by the present invention include a photocurable coating composition excellent in surface smoothness, an overprint excellent in surface smoothness and non-tackiness using the photocurable coating composition, and its It is to provide a manufacturing method.

The above object has been achieved by <1>, <7> or <8> described below. It is described below together with <2> to <6> which are preferred embodiments.
<1> A photocurable coating composition comprising (I) to (III), (I) a fluorine-containing polymer having a cyclic hydrocarbon group, (II) an ethylenically unsaturated compound, (III) Photopolymerization initiator,
<2> The photocurable coating composition according to <1>, wherein the fluoropolymer having a cyclic hydrocarbon group includes a monomer unit represented by the formula (1):

In the formula (1), Rf represents a fluoroalkyl group or a perfluoroalkyl group containing 5 or more fluorine atoms, n represents 1 or 2, and R ¹ represents a hydrogen atom or a methyl group.
<3> The photocurable coating composition according to <1> or <2>, wherein the ethylenically unsaturated compound includes a monofunctional ethylenically unsaturated compound and a polyfunctional ethylenically unsaturated compound,
<4> The photocurable coating composition according to any one of <1> to <3>, which has substantially no absorption in a visible region,
<5> The photocurable coating composition according to any one of <1> to <4>, which is for overprinting,
<6> The photocurable coating composition according to any one of <1> to <5>, which is for overprinting of an electrophotographic printed material,
<7> An overprint comprising an overprint layer obtained by photocuring the photocurable coating composition according to any one of <1> to <6> on an electrophotographic printed material,
<8> A step of obtaining an electrophotographic print by electrophotographic printing on a printing substrate, a step of applying the photocurable coating composition according to any one of <1> to <6> on the electrophotographic print And a method for producing an overprint, comprising the step of photocuring the photocurable coating composition.

  According to the present invention, a photocurable coating composition excellent in surface smoothness, an overprint having an overprint layer excellent in surface smoothness and non-tackiness using the photocurable coating composition, and The manufacturing method could be provided.

The photocurable coating composition of the present invention (hereinafter also simply referred to as “coating composition”) is characterized by containing (I) to (III).
(I) Fluoropolymer having cyclic hydrocarbon group (II) Ethylenically unsaturated compound (III) Photopolymerization initiator The overprint of the present invention is a photocuring of the photocurable coating composition of the present invention on an electrophotographic print. It is characterized by having an overprint layer. The method for producing an overprint of the present invention includes a step of electrophotographic printing on a printing 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 It includes the step of photocuring the coating composition.
Generally, polydimethylsiloxane having a low surface energy is added as a leveling agent to a photocurable coating composition for the purpose of improving surface smoothness (Japanese Patent Laid-Open No. 2005-321787). A material such as polydimethylsiloxane contributes to the improvement of the surface smoothness, but a long waiting time is required during the operation in order to completely smooth the surface. Further, since the material itself is a liquid, there is a drawback that the surface after curing is easily sticky due to the influence of polydimethylsiloxane unevenly distributed on the surface.
In the present invention, it is considered that the surface smoothness was improved because the surface energy of the photocurable coating composition was reduced by using the fluorine-containing polymer having a cyclic hydrocarbon group.
On the other hand, the fluorine-containing polymer having a specific structure has a cyclic hydrocarbon group, and as a result, the fluorine-containing polymer having a cyclic hydrocarbon group has a high Tg. It is considered that the surface stickiness of the cured film was suppressed by improving the film property. Hereinafter, the present invention will be described in detail.

<Photocurable coating composition>
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 rich in color, and an overprint visually close to a silver salt photographic print can be obtained.

(I) Fluoropolymer having a cyclic hydrocarbon group The photocurable coating composition of the present invention contains at least a fluoropolymer having a cyclic hydrocarbon group.
The fluorine-containing polymer having a cyclic hydrocarbon group that can be used in the present invention is a polymer having one or more cyclic hydrocarbon groups and containing a fluorine atom, and there is no particular limitation other than the above.

The cyclic hydrocarbon group in the fluoropolymer having a cyclic hydrocarbon group may be a group obtained by removing one or more hydrogen atoms from a hydrocarbon ring (an alicyclic ring, an aromatic ring, a condensed ring, a bridged ring, etc.). It may be a valent group or a divalent or higher valent group.
Moreover, the said cyclic hydrocarbon group may have a substituent in carbon which can be introduce | transduced.
Examples of substituents that can be introduced include alkyl groups, hydroxy groups, cyano groups, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), amino groups, carboxy groups, acyl groups, alkoxycarbonyl groups, and alkoxy groups. And a nitro group.

As said cyclic hydrocarbon group, an alicyclic hydrocarbon group and an aromatic ring hydrocarbon group can be illustrated preferably, and an alicyclic hydrocarbon group can be illustrated more preferably.
The ring constituting the cyclic hydrocarbon group is preferably a 3- to 7-membered ring, more preferably a 4- to 7-membered ring, and most preferably a 5- or 6-membered ring.
The alicyclic hydrocarbon group may contain a double bond.
The ring constituting the alicyclic hydrocarbon group may be a single ring, a condensed ring obtained by condensing a plurality of rings, or a bridged ring. It is preferable that it is a bridge ring, and more preferably a bridged ring.
Further, among the bridged rings, a bicyclo ring or a tricyclo ring is more preferable, and a ring having a double bond in the ring skeleton is particularly preferable.
The bicyclo ring or tricyclo ring in the present invention refers to a tricyclo ring when the number of ring-atom bond breaks required to open to a chain structure is 3 times, and a bicyclo ring as the case of 2 times, Such ring structures are referred to as a tricyclo ring and a bicyclo ring, respectively.
The ring constituting the aromatic hydrocarbon group may be a single ring or a condensed ring formed by condensing a plurality of rings.
The ring constituting the cyclic hydrocarbon group may be a ring in which an aromatic ring and an alicyclic ring are condensed.

The atoms forming the ring constituting the cyclic hydrocarbon group may contain heteroatoms such as an oxygen atom, a nitrogen atom, and a sulfur atom, but a carbon atom or a ring composed of an oxygen atom and a carbon atom Is preferable, and a ring composed of carbon atoms is more preferable.
The number of carbon atoms forming the ring constituting the alicyclic hydrocarbon group is preferably 6-18, and more preferably 7-12.
The ring constituting the alicyclic hydrocarbon group may have a substituent if it can be introduced. Preferred examples of the substituent include relatively short-chain alkyl groups having about 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

  The ring constituting the cyclic hydrocarbon group preferably has the following structures (R-1) to (R-8). In the present invention, in the chemical formula, the hydrocarbon chain may be described by a simplified structural formula in which symbols of carbon (C) and hydrogen (H) are omitted.

  Among these, (R-3), (R-5), (R-7) or (R-8) is particularly preferable.

The cyclic hydrocarbon group in the fluorine-containing polymer having a cyclic hydrocarbon group is preferably in the side chain in the polymer, and more preferably in the terminal of the side chain in the polymer.
The fluorine-containing polymer having a cyclic hydrocarbon group may have only one kind of cyclic hydrocarbon group or two or more kinds.
Moreover, the fluorine-containing polymer which has a cyclic hydrocarbon group may be used individually by 1 type, and may use 2 or more types together.

The fluorine-containing polymer having a cyclic hydrocarbon group preferably has a group containing a fluorine atom represented by Rf shown below.
By using Rf having 5 or more fluorine atoms, the surface energy of the photocurable coating composition can be reduced, and the surface smoothness can be improved.

Rf is more preferably a fluoroalkyl group or a perfluoroalkyl group represented by the formula (2).
_{Rf = C x F y H z} (2)
In Formula (2), x represents an integer of 2 to 15, y represents an integer of 5 to 2x + 1, and y + z is 2x + 1.
x represents the number of carbon atoms contained in Rf, preferably 2-15, more preferably 2-12, and even more preferably 2-8.

The number y of fluorine atoms is preferably 5-30, more preferably 9-25, and still more preferably 9-17.
By using a fluorine-containing polymer having a cyclic hydrocarbon group having a fluorine atom in this range, excellent surface smoothness can be obtained. Moreover, since the fall of the solubility resulting from the oil repellency of a fluorine atom does not arise, it is preferable.

When Rf is a perfluoroalkyl group C _x F _{2x + 1} , Rf may be linear or branched, and is preferably linear, that is, (CF ₂ ) _x F. The range of x is the same as the range of x described above, and the same applies to the preferable range.
When Rf is a fluoroalkyl group, Rf may be linear or branched, and is preferably linear (CF ₂ ) _x H. The range of x is the same as the range of x described above, and the same applies to the preferable range.

  In the present invention, Rf is preferably a linear perfluoroalkyl group, specifically, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, Examples thereof include a perfluoroheptyl group and a perfluorooctyl group, and among them, a perfluoroethyl group, a perfluorobutyl group, a perfluorohexyl group, and a perfluorooctyl group are more preferable.

The fluorine-containing polymer having a cyclic hydrocarbon group that can be used in the present invention is preferably an addition polymerization resin polymerized by addition polymerization, and more preferably a radical polymerization resin polymerized by radical polymerization.
The fluoropolymer having a cyclic hydrocarbon group is preferably a copolymer of a monomer having a group containing a fluorine element and a monomer having a cyclic hydrocarbon group.

  The fluorine-containing polymer having a cyclic hydrocarbon group preferably has at least a monomer unit represented by the following formula (1).

In the formula (1), Rf represents a fluoroalkyl group or a perfluoroalkyl group containing 5 or more fluorine atoms, n represents 1 or 2, and R ¹ represents a hydrogen atom or a methyl group.
The preferable range of Rf is synonymous with Rf shown in Formula (2), and the preferable range is also the same.
Within the above range, excellent surface smoothness can be obtained by the fluorine-containing polymer having a cyclic hydrocarbon group.
Further, the fluorine-containing polymer having a cyclic hydrocarbon group may have one kind of monomer unit containing a fluorine atom as represented by the formula (1), or two or more kinds. May be.

  Further, the fluorine-containing polymer having a cyclic hydrocarbon group preferably has a monomer unit containing a fluorine atom in a range of 1 to 60 mol%, and in a range of 5 to 50 mol% in all monomer units. It is more preferable to have, and it is still more preferable to have in the range of 10-30 mol%. When the content of the monomer unit containing a fluorine atom is 1 mol% or more, desired surface smoothness can be obtained. Moreover, the solubility of the fluorine-containing polymer which has a cyclic hydrocarbon group is enough that content of the monomer unit containing a fluorine atom is 60 mol% or less.

  The fluorine-containing polymer having a cyclic hydrocarbon group preferably has at least a monomer unit having a cyclic hydrocarbon group represented by the following formula (3).

R ⁶ in the formula (3) represents a hydrocarbon group or a hydrogen atom having 1 to 4 carbon atoms, preferably a methyl group or a hydrogen atom.
Z in Formula (3) represents a divalent linking group or a single bond, and is an oxygen atom, —CO—, —S—, —NR ⁷ —, an alkylene group having 1 or more carbon atoms, or a combination of two or more thereof. It is preferable that
Here, R ⁷ represents a hydrogen atom or an alkyl group having 1 or more carbon atoms, preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, Particularly preferred is an alkyl group having 1 to 4 carbon atoms. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-butyl group, an n-hexyl group, and an n-nonyl group, and a methyl group, an ethyl group, and a butyl group are more preferable.
The alkylene group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 4 carbon atoms.
Specific examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, and a nonylene group, and a methylene group, an ethylene group, a propylene group, and a butylene group are more preferable.
In addition, the alkyl group and the alkylene group may be linear or branched.
The group in which two or more are combined is preferably a group having an ether bond (—O—) in an alkylene chain composed of a methylene group, and particularly preferably a group having an ether bond (—O—) at both ends of the alkylene group.
L in Formula (3) represents a cyclic hydrocarbon group, and the ring constituting the cyclic hydrocarbon group is preferably a condensed ring or a bridged ring.

  Although there is no restriction | limiting in particular as a monomer which has a cyclic hydrocarbon group used for manufacture of the fluorine-containing polymer which has a cyclic hydrocarbon group, It has a (meth) acrylate compound and cyclic hydrocarbon group which have a cyclic hydrocarbon group (meta ) An acrylamide compound and / or a styrene derivative is preferable, and a (meth) acrylate compound having a cyclic hydrocarbon group is more preferable.

  The fluorine-containing polymer having a cyclic hydrocarbon group may have one or more monomer units each having the cyclic hydrocarbon group, and may also have two or more monomer units containing a fluorine atom. May be the same monomer unit, that is, a monomer unit containing a cyclic hydrocarbon group and a fluorine atom.

  The fluorine-containing polymer having a cyclic hydrocarbon group is preferably a polymer obtained by copolymerizing at least a monomer represented by the formula (1-1) and a monomer represented by the formula (3-1). A polymer obtained by copolymerizing only the monomer represented by 1-1) and the monomer represented by the following formula (3-1) is more preferable.

R ¹ and n in the formula (1-1) have the same meanings as R ¹ , n and Rf in the formula (1), and preferred ranges thereof are also the same.
R ⁶ in the formula (3-1), Z and L, the equation (3) has the same meaning as R ^6, Z and L in, a preferred range is also the same.

  Specific examples of monomers having a cyclic hydrocarbon group that can be suitably used in the present invention [Exemplary compounds (B-1) to (B-31), (b-1) to (b-38), (C- 1) to (C-2) and (D-1) to (D-20)] are shown below, but the present invention is not limited thereto. Moreover, when stereoisomers exist in each exemplified compound, any of them may be used, and a mixture of stereoisomers may be used. In the following specific examples, Me represents a methyl group.

  Further, in the fluorine-containing polymer having a cyclic hydrocarbon group, the content of monomer units having a cyclic hydrocarbon group is preferably 20 to 99 mol%, and preferably 40 to 95 mol% in all monomer units. Is more preferable, and it is still more preferable that it is 60-90 mol%. When the content of the monomer unit having a cyclic hydrocarbon group is 20 mol% or more, the glass transition point (Tg) of the polymer is lowered, and the surface stickiness suppression performance is excellent. Moreover, the surface energy of a polymer is moderate as it is 99 mol% or less, and the surface smoothness of a coating composition is excellent.

The fluorine-containing polymer having a cyclic hydrocarbon group may have other monomer units in addition to the monomer unit containing a fluorine atom and the monomer unit having a cyclic hydrocarbon group.
The other monomer unit may be a monomer unit formed from a known monomer, and is preferably a monomer unit formed from a known radical polymerizable monomer, and is a (meth) acrylate compound and / or ( It is more preferably a monomer unit formed from a (meth) acrylamide compound.

The monomer that can be used for the production of the fluorine-containing polymer having a cyclic hydrocarbon group is not particularly limited, but is preferably a radical polymerizable monomer, and more preferably a monomer having an ethylenically unsaturated bond. .
Examples of the radical polymerizable monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and their salts, 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, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, N-methylol acrylamide , Acrylic acid derivatives such as diacetone acrylamide and epoxy acrylate, methacrylic derivatives such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, N-vinyl pyrrolidone, N-vinyl Examples include N-vinyl compounds such as caprolactam, and derivatives of allyl compounds such as allyl glycidyl ether, diallyl phthalate, and triallyl trimellitate, and more specifically, Shinzo Yamashita, “Handbook of Crosslinking Agents” (1981) , Taiseisha; Kato Kiyomi, "UV / EB Curing Handbook (Raw Materials)" (1985, Polymer Publishing Society); Radtech Study Group, "Application and Market of UV / EB Curing Technology", page 79 (1989, CMC Co.); Eiichiro Takiyama, “Polyester Resin Handbook”, (1988, Nikkan Kogyo Shimbun Co., Ltd.) and the like or a monofunctional radical polymerizable monomer known in the industry may be used. it can.

  Moreover, it is preferable that the fluorine-containing polymer which has a cyclic hydrocarbon group is a polymer represented by Formula (4).

（式（４）中、Ｒ^fはフッ素原子を含む基を表し、Ｒ^Cは環状炭化水素基を含む基を表し、Ｒ^Nはフッ素原子及び環状炭化水素基を含まない有機基を表し、Ｒ^x、Ｒ^y及びＲ^zはそれぞれ独立に、水素原子又はメチル基を表し、ｘは１〜６０を表し、ｙは２０〜９９を表し、ｚは０〜７９を表し、また、ｘ＋ｙ＋ｚ＝１００である。）

(In the formula (4), R ^f represents a group containing a fluorine atom, R ^C represents a group containing a cyclic hydrocarbon group, R ^N represents an organic group not containing a fluorine atom and a cyclic hydrocarbon group, R ^x , R ^y and R ^z each independently represents a hydrogen atom or a methyl group, x represents 1 to 60, y represents 20 to 99, z represents 0 to 79, and x + y + z = 100 is there.)

R ^f in Formula (4) represents a group containing a fluorine atom, and is preferably a group having at least a group containing a fluorine atom represented by Formula (A). In Formula (B) or Formula (C), A group having at least a group containing a fluorine atom is more preferable.
R ^C in Formula (4) represents a group containing a cyclic hydrocarbon group. The cyclic hydrocarbon group is preferably an alicyclic hydrocarbon group and an aromatic ring hydrocarbon group, more preferably an alicyclic hydrocarbon group, and further preferably a group obtained by removing one hydrogen electron from a bicyclo ring or a tricyclo ring. .
R ^N in formula (4) represents an organic group containing no fluorine atom and a cyclic hydrocarbon group, -COOR ^B, or is preferably -CONHR ^B. R ^B represents a monovalent organic group, preferably a hydrocarbon group having 1 to 20 carbon atoms, and more preferably a methyl group.
X, y and z in the formula (4) represent the molar ratio of each monomer unit, and x + y + z = 100.
X in Formula (4) represents 1-60, 3-50 are preferable and 10-30 are more preferable.
Y in Formula (4) represents 20-99, 40-95 are preferable and 60-90 are more preferable.
Z in Formula (4) represents 0 to 79, preferably 0 to 20, and more preferably 0.
Each monomer unit in formula (4) may be used alone or in combination of two or more.
Moreover, it is preferable that the terminal of the polymer represented by Formula (4) is a hydrogen atom.

  Specific examples of the fluorine-containing polymer having a cyclic hydrocarbon group that can be suitably used in the present invention are shown below, but the present invention is not limited thereto. In the following specific examples, the numbers appended to the parentheses of each monomer unit represent the molar ratio of each monomer unit in the polymer.

  In addition, the content of the fluorine-containing polymer having a cyclic hydrocarbon group in the photocurable coating composition of the present invention is based on the weight of the entire photocurable coating composition from the viewpoints of surface tackiness suppression and surface smoothness. Thus, the range is preferably 0.0001 to 40% by weight, and more preferably 0.001 to 20% by weight.

  The weight average molecular weight of the fluorine-containing polymer having a cyclic hydrocarbon group is preferably 3,000 to 300,000, more preferably 4,000 to 100,000, and 5,000 to 50,000. More preferably.

  Further, the glass transition point (Tg) of the fluoropolymer having a cyclic hydrocarbon group is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 50 ° C. or higher. Moreover, it is preferable that it is 350 degrees C or less.

(II) Ethylenically unsaturated compound The photocurable coating composition of the present invention comprises (II) an ethylenically unsaturated compound. Examples of the ethylenically unsaturated compound that can be used in the present invention include a radical polymerizable compound and a cationic polymerizable compound.

The compound having an ethylenically unsaturated bond that can be used in the present invention is not particularly limited as long as it is a compound capable of radical polymerization or cationic polymerization.
The radical polymerizable compound in the present invention may be any compound as long as it has at least one ethylenically unsaturated bond, 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.
The ethylenically unsaturated compound preferably contains a polyfunctional ethylenically unsaturated compound, and more preferably contains a monofunctional ethylenically unsaturated compound and a polyfunctional ethylenically unsaturated compound. preferable.

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 bonds, acrylonitrile, styrene Furthermore, radically polymerizable compounds such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides and unsaturated urethanes can be mentioned.
The (meth) acrylate represents acrylate or methacrylate, and (meth) acrylamide represents acrylamide or methacrylamide. In the present invention, for example, a monofunctional (meth) acrylate compound represents a compound having only one (meth) acryloxy group, and further has an ethylenically unsaturated bond other than the (meth) acryloxy group. Also good.

Specifically, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, bis (4- (Acryloxypolyethoxyphenyl) propane, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene Glycol diacrylate, pentaerythritol tria Relate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, 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, 2-ethylhexyl methacrylate, lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, 1,6-hexanediol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene Glycol derivatives such as glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, N-vinylpyrrolidone, N-vinylcaprolactam Derivatives of allyl compounds such as N-vinyl compounds such as allyl glycidyl ether, diallyl phthalate, triallyl trimellitate, and the like. More specifically, Yamashita Shinzo, “Crosslinking Agent Handbook” (1981, Taiseisha); edited by Kiyomi Kato, “UV / EB Curing Handbook (raw material)” (1985, Polymer Publishing Society); edited by Radtech Research Group, “Application and Market of UV / EB Curing Technology”, page 79, (1989, CMC) Commercially available products described in Eiichiro Takiyama, “Polyester Resin Handbook”, (1988, Nikkan Kogyo Shimbun Co., Ltd.) or the like, or radically polymerizable or crosslinkable monomers, oligomers, and polymers known in the industry can be used.
Among these, it is preferable to use trimethylolpropane triacrylate, tripropylene glycol diacrylate, lauryl acrylate, hexanediol diacrylate, and the like.

  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 from the viewpoint of curability, adhesion, and surface hardness, and a divinyl ether compound is particularly preferable. 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 “acrylate compound”). More preferably, they are the following compounds.

  That is, 2-ethylhexyl diglycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxybutyl acrylate, hydroxypivalate neopentyl glycol diacrylate, 2-acryloyloxyethyl phthalate, methoxypolyethylene glycol acrylate, tetramethylol Methane triacrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, dimethylol tricyclodecane diacrylate, ethoxylated phenyl acrylate, 2-acryloyloxyethyl succinic acid, nonylphenol ethylene oxide (EO) adduct acrylate, Modified glycerin triacrylate, bisphenol A diglycidyl ether acrylic acid adduct, modified bisphenol A diacrylate , Phenoxypolyethylene glycol acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, propylene oxide (PO) adduct diacrylate of bisphenol A, EO adduct diacrylate of bisphenol A, dipentaerythritol hexaacrylate, pentaerythritol triacrylate Tolylene diisocyanate urethane prepolymer, lactone-modified flexible acrylate, butoxyethyl acrylate, propylene glycol diglycidyl ether acrylic acid adduct, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, 2-hydroxyethyl acrylate, methoxydi Propylene glycol acrylate, ditrimethylolpropane tetraacrylate, Data triacrylate hexamethylene diisocyanate urethane prepolymer, stearyl acrylate, isoamyl acrylate, isomyristyl acrylate, isostearyl acrylate, lactone-modified acrylate.

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

  The content of the (II) ethylenically unsaturated compound in the photocurable coating composition of the present invention is preferably 50 to 95% by weight based on the total weight of the photocurable coating composition, and is preferably 60 to 90%. More preferably, it is 70% by weight. It is preferable for it to be in the above-mentioned numerical range because of excellent non-tackiness.

The photocurable coating composition of the present invention preferably contains a polyfunctional ethylenically unsaturated compound as the ethylenically unsaturated compound, and may contain a monofunctional ethylenically unsaturated compound and a polyfunctional ethylenically unsaturated compound. More preferred.
When using a polyfunctional ethylenically unsaturated compound, it is preferable that content of a polyfunctional ethylenically unsaturated compound is 5 to 60 weight% with respect to the total weight of a photocurable coating composition. When the content of the polyfunctional ethylenically unsaturated compound is 5% by weight or more, non-tackiness is excellent, and when it is 60% by weight or less, the viscosity of the photocurable coating composition is appropriate, so that the surface smoothness is improved. Excellent.

  In the present invention, in addition to the combination of a radical polymerizable compound and a radical photopolymerization initiator according to various purposes, a cation polymerizable compound and a cationic photopolymerization initiator as shown below are used in combination with them. Alternatively, a radical-cation hybrid coating composition may be used.

The cationically polymerizable compound that can be used in the present invention is not particularly limited as long as it is a compound that initiates a polymerization reaction with an acid generated from a photoacid generator and cures, and various known compounds known as photocationically polymerizable monomers. Cationic polymerizable monomers can be used.
When the cationically polymerizable compound to be used does not have an ethylenically unsaturated bond, a compound having an ethylenically unsaturated bond and a cationically polymerizable compound having no ethylenically unsaturated bond are used in combination.
Examples of the cationic polymerizable compound 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 JP-A-2001-2001. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in each publication such as No. 220526.

  In addition, as the cationic polymerizable compound, for example, a polymerizable compound applied to a cationic polymerization type photocurable resin is known, and recently, a photo cationic polymerization type sensitized in a visible light wavelength region of 400 nm or more. Examples of the polymerizable compound applied to the photo-curable resin are disclosed in JP-A-6-43633 and JP-A-8-324137. These can also be applied to the coating composition of the present invention.

<Photopolymerization initiator>
The coating composition of the present invention contains 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 above-described ethylenically unsaturated compounds. Preferably, it is 0.5 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 ₆ ⁻ , CF ₃ SO ₃ ⁻ salt of an aromatic onium compound such as diazonium, ammonium, iodonium, sulfonium or phosphonium. Can be mentioned. 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, The disulfide compound of 56-75643 gazette etc. are mentioned.
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), Si described in JP-A-8-54735 -H, Ge-H compounds and the like.

<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, polydimethylsiloxane 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, surfactants, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, waxes and the like are appropriately selected and added. be able to.

  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 Examples thereof include a low molecular weight tackifying resin having an unsaturated bond.

<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, as described in the following US patents.
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.

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

<Synthesis of fluorinated polymer having cyclic hydrocarbon group>
(Synthesis method of fluorine-containing polymer (P-1) having a cyclic hydrocarbon group)
R-1620 (manufactured by Daikin Industries, Ltd.) (0.2 mol), FA-513A (manufactured by Hitachi Chemical Co., Ltd.) (0.8 mol), and 2,2′-azobis (2-methylbutyronitrile) ) (Manufactured by Wako Pure Chemical Industries, Ltd.) (0.04 mol) in a 1-methoxy-2-propanol (300 g) solution at 80 ° C. in a nitrogen stream. (300 g) was added dropwise over 4 hours. After completion of the dropping, the mixture was further stirred at 85 ° C. for 3 hours to obtain a fluoropolymer (P-1) having a cyclic hydrocarbon group. When this fluorine-containing polymer (P-1) which has a cyclic hydrocarbon group was measured by the gel permeation chromatography method, the weight average molecular weight was 24,000. Furthermore, the structure of the obtained fluoropolymer (P-1) having a cyclic hydrocarbon group was identified by NMR.

  Polymers (P-2) to (P-23) and comparative polymers (Z-2) to (Z-5) of the present invention were synthesized by the same method as above. Comparative polymers (Z-2) to (Z-5) will be described in detail later.

[Example 1]
The following components were stirred with a stirrer to obtain a photocurable coating composition.
・ Trimethylolpropane triacrylate (made by Shin-Nakamura Chemical Co., Ltd.) 40% by weight
Tripropylene glycol diacrylate (Aldrich) 20% by weight
-Dodecyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 20% by weight
・ IRGACURE 907 (Ciba Specialty Chemicals) 15% by weight
・ Benzophenone (Tokyo Chemical Industry Co., Ltd.) 3% by weight
・ Fluorine-containing polymer (P-1) having a cyclic hydrocarbon group shown in Table 1 2% by weight

  The obtained solventless type photocurable coating composition of Example 1 was evaluated for performance by the following method.

<Evaluation of surface smoothness (leveling property)>
For electrophotographic prints output to double-sided 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

[Examples 2 to 10 and Comparative Examples 1 to 5]
A photocurable coating composition was prepared in the same manner as in Example 1 except that the fluorine-containing polymer having a cyclic hydrocarbon group was changed to the polymer shown in Table 1, and then this was used to produce an overprint. Then, these performance evaluations were performed. The evaluation results are summarized in Table 1.

[Comparative Example 6]
In Example 1, instead of fluorine-containing polymer (P-1) having a cyclic hydrocarbon group (2% by weight) and dodecyl acrylate (20% by weight), 22% of trimethylolpropane triacrylate (Shin Nakamura Chemical) was used. % (62% by weight in total) was used, and a photocurable coating composition was prepared in the same manner as in Example 1 and then used to make an overprint to evaluate the performance. It was. The evaluation results are shown in Table 1.

In the table, Z-1 to Z-5 represent the following compounds Z-1 to Z-5.
Z-1 Polydimethylsiloxane (manufactured by Aldrich) Mw 11.0 × 10 ⁴

  The structures of the comparative polymers (Z-2) to (Z-5) are as follows.

(Example 11)
Twenty printed materials were produced by electrophotographic printing full color images of several frames each on both sides of A4 size double-side coated paper (basis weight 100 g / m ² ). Each of the photocurable coating compositions prepared in 10 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 an overprint. 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 12
A full color image including a menu photo and text were electrophotographic printed on both sides of 10 sheets of A3 size double coated paper (basis weight 100 g / m ² ). The photocurable coating compositions prepared in Examples 1 to 10 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 (8)

A photocurable coating composition comprising (I) to (III).
(I) Fluoropolymer having cyclic hydrocarbon group (II) Ethylenically unsaturated compound (III) Photopolymerization initiator The photocurable coating composition of Claim 1 in which the fluorine-containing polymer which has the said cyclic hydrocarbon group contains the monomer unit represented by Formula (1).

In the formula (1), Rf represents a fluoroalkyl group or a perfluoroalkyl group containing 5 or more fluorine atoms, n represents 1 or 2, and R ¹ represents a hydrogen atom or a methyl group.   The photocurable coating composition according to claim 1 or 2, wherein the ethylenically unsaturated compound includes a monofunctional ethylenically unsaturated compound and a polyfunctional ethylenically unsaturated compound.   The photocurable coating composition according to any one of claims 1 to 3, which has substantially no absorption in the visible region.   The photocurable coating composition according to any one of claims 1 to 4, which is used for overprinting.   The photocurable coating composition according to any one of claims 1 to 5, which is for overprinting of an electrophotographic printed material.   An overprint comprising an overprint layer obtained by photocuring the photocurable coating composition according to claim 1 on an electrophotographic print. A step of obtaining an electrophotographic print by electrophotographic printing on a printing substrate;
Applying the photocurable coating composition according to any one of claims 1 to 6 on the electrophotographic printed material; and
A method for producing an overprint, comprising a step of photocuring the photocurable coating composition.