JP2011195732A - Cured film and method for forming cured film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cured film capable of suppressing time-dependent deterioration of the film after stretching and a method for forming such a cured film.SOLUTION: The cured film is obtained by curing a film of a radiation-curable composition containing (A) a radical polymerizable compound having an ethylenically unsaturated group and (B) a polymerization initiator by irradiation with active radiation, the cured film is heated and stretched so that at least a part of the film attains to a stretching rate of ≥100%, and a polymer formed by the polymerization of the radical polymerizable compound in the film has a weight average molecular weight Mw of 5,000-50,000.

Description

  The present invention relates to a cured film and a method for forming a cured film.

As an image recording method for forming an image on a recording medium such as paper based on an image data signal, there are an electrophotographic method, a sublimation type and a melt type thermal transfer method, an ink jet method and the like. The electrophotographic system requires a process of forming an electrostatic latent image on a photosensitive drum by charging and exposure, and there is a problem that the system becomes complicated and consequently the manufacturing cost becomes high. In addition, although the thermal transfer system is inexpensive, there are problems such as high running costs and waste materials due to the use of ink ribbons.
On the other hand, the ink jet method is an inexpensive device and ejects ink only to the required image portion to form an image directly on the recording medium, so that the ink composition can be used efficiently and the running cost is low. . Furthermore, there is little noise and it is excellent as an image recording method.

Patent Document 1 discloses an active energy ray-curable ink for an ink jet containing a polymerizable monomer, wherein the polymerizable monomer is 95 to 99.99% by weight of a monofunctional monomer with respect to the entire polymerizable monomer. When a cured film having a functional monomer content of 0.01 to 5% by weight and formed using an active energy ray-curable ink and having a thickness of 10 μm is stretched at a temperature of 170 ° C. and a strain rate of 2 / min, the cured film has ductility. An active energy ray-curable ink is disclosed, characterized in that is over 120%.
Patent Documents 2 to 4 disclose image forming methods using a cationic polymerization type ink containing a compound having an oxetane ring.

International Publication No. 2007/013368 JP 2004-90303 A Japanese Patent No. 4032174 Japanese Patent No. 4312050

  The objective of this invention is providing the formation method of the cured film which can suppress the time-dependent deterioration of the film | membrane after an extending | stretching process, and a cured film.

The above object has been achieved by the means described in <1> or <7> below. It is shown below with <2>-<6> and <8>-<12> which are preferable embodiments.
<1> A film of a radiation curable composition containing (Component A) a radically polymerizable compound having an ethylenically unsaturated group and (Component B) a polymerization initiator is cured by irradiation with actinic radiation, and at least The weight average molecular weight Mw of a polymer formed by polymerization of the radical polymerizable compound in the film is 5,000 or more and 50,000 or less by heating and drawing so that a part of the film has a drawing ratio of 100% or more. A cured film characterized by
<2> The cured film according to the above <1>, wherein the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the polymer formed by polymerization of the radical polymerizable compound is 2 or more,
<3> The cured film according to <1> or <2>, wherein the film surface temperature of the film of the radiation curable composition at the time of curing by irradiation with the active radiation is 40 ° C. or higher,
<4> Any one of the above <1> to <3>, wherein the illuminance of the active radiation on the surface of the film of the radiation curable composition upon curing by irradiation with the active radiation is 1 W / cm ² or more. Cured film according to
<5> The cured film according to any one of <1> to <4>, wherein the ratio of the monofunctional polymerizable compound in Component A is 95% by weight or more.
<6> The above <1> to <5>, wherein the radiation curable composition further contains a polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group. A cured film according to any one of
<7> A radiation curable composition containing (Component A) a radically polymerizable compound having an ethylenically unsaturated group and (Component B) a polymerization initiator is provided on a support, and the radiation curable composition is provided. A composition applying step for forming the film, a curing step for curing the film of the radiation curable composition by irradiation with actinic radiation to form a cured film, and at least a stretch ratio of a part of the cured film is 100%. And a heat-stretching step for heat-stretching so that the weight average molecular weight Mw of the polymer formed by polymerization of the radical polymerizable compound in the cured film is 5,000 or more and 50,000 or less. A method for forming a cured film,
<8> The method for forming a cured film according to the above <7>, wherein the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the polymer formed by polymerization of the radical polymerizable compound is 2 or more. ,
<9> In the said hardening process, the film surface temperature of the film | membrane of the said radiation curable composition is 40 degreeC or more, The formation method of the cured film as described in said <7> or <8>,
<10> In any one of the above <7> to <9>, in the curing step, the illuminance of the active radiation on the surface of the film of the radiation curable composition is 1 W / cm ² or more. Method for forming a cured film,
<11> The method for forming a cured film according to any one of the above <7> to <10>, wherein the ratio of the monofunctional polymerizable compound in the component A is 95% by weight or more.
<12> The above <7> to <11>, wherein the radiation curable composition further contains a polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group. The formation method of the cured film as described in any one of these.

  ADVANTAGE OF THE INVENTION According to this invention, the formation method of the cured film which can suppress the time-dependent deterioration of the film | membrane after an extending | stretching process, and a cured film could be provided.

In the method for forming a cured film of the present invention, a radiation curable composition containing (Component A) a radical polymerizable compound having an ethylenically unsaturated group and (Component B) a polymerization initiator is applied to a support. A composition applying step of forming a film of the radiation curable composition, a curing step of curing the film of the radiation curable composition by irradiation with actinic radiation to form a cured film, and at least one of the cured films And a heat-stretching step of heat-stretching so that the stretch ratio of the part becomes 100% or more, and the weight average molecular weight Mw of the polymer formed by the polymerization of the radical polymerizable compound in the cured film is 5,000 It is above 50,000 or less.
The method for forming a cured film of the present invention can be suitably used for a method for forming a cured film using an ink composition, preferably an ink composition for inkjet recording.
Hereinafter, the radiation curable composition that can be used in the method for forming a cured film of the present invention will be described in detail, and then the method for forming a cured film of the present invention will be described in detail.
In addition, in this invention, description of "A-B" showing a numerical range means "A or more and B or less" unless there is particular notice. That is, it means a numerical range including A and B which are end points.
Further, in the present invention, when referring to both or one of “acrylate” and “methacrylate”, it is also referred to as “(meth) acrylate”, and when referring to both or one of “acryl” and “methacryl” “( Also described as “meth) acryl”.

(1) Radiation curable composition The radiation curable composition of the present invention contains (Component A) a radically polymerizable compound having an ethylenically unsaturated group and (Component B) a polymerization initiator.
The radiation curable composition of the present invention can be suitably used as an ink composition, preferably an ink composition for inkjet recording.

  The term “radiation” as used in the present invention is not particularly limited as long as it is an actinic radiation capable of imparting energy capable of generating an initiation species in a radiation curable composition by the irradiation, and is broadly α-ray, γ-ray. , X-rays, ultraviolet rays (UV), visible rays, electron beams, etc. Among them, ultraviolet rays and electron beams are preferable from the viewpoint of curing sensitivity and device availability, and ultraviolet rays are particularly preferable. Therefore, the radiation curable composition of the present invention is preferably one that can be cured by irradiating ultraviolet rays as radiation.

(Component A) Radical polymerizable compound The radiation-curable composition of the present invention contains (Component A) a radical polymerizable compound having an ethylenically unsaturated group.
The radically polymerizable compound that can be used in the present invention is a compound having an ethylenically unsaturated group capable of radical polymerization and any compound having at least one ethylenically unsaturated group capable of radical polymerization in the molecule. These may include those having chemical forms such as monomers, oligomers and polymers, and monomers and oligomers can be preferably used. One kind of radically polymerizable compound may be contained in any ratio in order to improve the desired properties, and two or more kinds thereof may be contained.
Examples of the radical polymerizable compound include photopolymerizable compositions described in JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, and the like. There is known a photo-curing material using the above.

  Examples of radically polymerizable compounds having an ethylenically unsaturated group capable of radical polymerization include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, their esters and their Salts, ethylenically unsaturated anhydrides, acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, unsaturated urethane (meth) acrylic monomers or prepolymers, epoxy monomers or prepolymers (Meth) acrylic acid esters such as polymers, urethane monomers or prepolymers are preferably used.

  Specifically, (poly) ethylene glycol mono (meth) acrylate, (poly) ethylene glycol (meth) acrylate methyl ester, (poly) ethylene glycol (meth) acrylate ethyl ester, (poly) ethylene glycol (meth) acrylate phenyl Ester, (poly) propylene glycol mono (meth) acrylate, (poly) propylene glycol mono (meth) acrylate phenyl ester, (poly) propylene glycol (meth) acrylate methyl ester, (poly) propylene glycol (meth) acrylate ethyl ester, (Poly) propylene glycol diglycidyl ether acrylic acid adduct, neopentyl glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, Poly) tetramethylene glycol di (meth) acrylate, (poly) tetramethylene glycol di (meth) acrylate, PO (propylene oxide) adduct di (meth) acrylate of bisphenol A, ethoxylated neopentyl glycol diacrylate, propoxylated neo Pentyl glycol diacrylate, EO (ethylene oxide) adduct di (meth) acrylate of bisphenol A, EO-modified pentaerythritol triacrylate, PO (propylene oxide) -modified pentaerythritol triacrylate, EO-modified pentaerythritol tetraacrylate, PO-modified pentaerythritol Tetraacrylate, EO-modified dipentaerythritol tetraacrylate, PO-modified dipentaerythritol tetraacrylate , EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, EO-modified tetramethylolmethane tetraacrylate, PO-modified tetramethylolmethane tetraacrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, n- Decyl acrylate, isooctyl acrylate, n-lauryl acrylate, n-tridecyl acrylate, n-cetyl acrylate, n-stearyl acrylate, isomyristyl acrylate, isostearyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, tetrahydrofurfuryl acrylate , Benzyl acrylate, pentaerythritol triacrylate, pentaerythritol Acrylic acid derivatives such as methyl tetraacrylate, dipentaerythritol tetraacrylate, trimethylolpropane triacrylate, oligoester acrylate, isoamyl acrylate, N-methylol acrylamide, diacetone acrylamide, epoxy acrylate, methyl methacrylate, n-butyl methacrylate, 2 -Ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, n-decyl methacrylate, isooctyl methacrylate, n-lauryl methacrylate, n-tridecyl methacrylate, n-cetyl methacrylate, n-stearyl methacrylate, allyl methacrylate, glycidyl methacrylate, Benzyl methacrylate, dimethylaminomethyl methacrylate Methacryl derivatives such as trimethylolethane trimethacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, and other derivatives of allyl compounds such as allyl glycidyl ether, diallyl phthalate, triallyl trimellitate, 1,6 -Hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxybutyl acrylate, hydroxypivalin Acid neopentyl glycol diacrylate, 2-acryloyloxyethyl phthalic acid, nonylphenol EO adduct acrylate, methoxy-polyethylene glycol acrylate, 2-a Liloyloxyethyl-2-hydroxyethylphthalic acid, dimethylol tricyclodecane diacrylate, ethoxylated phenyl acrylate, 2-acryloyloxyethyl succinic acid, modified glycerin triacrylate, bisphenol A diglycidyl ether acrylic acid adduct, modified bisphenol A diacrylate, phenoxy-polyethylene glycol acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, dipentaerythritol hexaacrylate, tolylene diisocyanate urethane prepolymer, lactone-modified flexible acrylate, butoxyethyl acrylate, hexamethylene diisocyanate urethane pre Polymer, 2-hydroxyethyl acrylate, methoxydipropylene glycol acrylate, ditrime Tyrololpropane tetraacrylate and hexamethylene diisocyanate urethane prepolymers are listed. More specifically, Yamashita Shinzo “Cross-linking agent handbook” (1981, Taiseisha); Kato Kiyosumi “UV / EB curing handbook (raw material) ”(1985, Polymer Press Society); Radtech Research Group,“ Application and Market of UV / EB Curing Technology ”, page 79 (1989, CMC); Eiichiro Takiyama,“ Polyester Resin Handbook ”(1988, Nikkan) Commercially available products as described in Kogyo Shimbun) or radically polymerizable or crosslinkable monomers, oligomers and polymers known in the industry can be used.

  These acrylate compounds can have a relatively lower viscosity than the polymerizable compounds conventionally used in radiation curable compositions such as ink compositions, and stable ejection properties of radiation curable compositions can be obtained. Polymerization sensitivity and adhesion to a support such as a recording medium are also favorable, which is preferable.

Furthermore, it is also preferable to use a vinyl ether compound as the radical polymerizable compound, which can be roughly classified into a monovinyl ether compound and a di- or trivinyl ether 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; ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, hydroxyethyl monovinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexylbi Ether ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, hydroxynonyl monovinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, octadecyl vinyl ether, etc. Can be mentioned.
Of these vinyl ether compounds, divinyl ether compounds and trivinyl ether compounds are preferable from the viewpoints of curability, adhesion, and surface hardness, and divinyl ether compounds are 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.

Moreover, as a radically polymerizable compound, the ethylenically unsaturated compound which has a polycyclic structure can be mentioned preferably.
Specifically, a radical polymerizable compound having a norbornyl structure, an isobornyl structure, a dicyclopentanyl structure, a dicyclopentenyl structure or an adamantyl structure is preferable. A radically polymerizable compound having a polycyclic structure is preferable because it has high reactivity, low viscosity, and excellent adhesion to a support such as a recording medium.
Although the ethylenically unsaturated compound which has a polycyclic structure which can be preferably used in this invention is illustrated below, this invention is not limited to this. In the chemical structural formula of the present invention, the hydrocarbon chain may be described by a simplified structural formula in which symbols of carbon (C) and hydrogen (H) are omitted.

Moreover, as a radically polymerizable compound, N-vinyl lactams can be mentioned preferably.
Preferable examples of N-vinyl lactams include compounds represented by the following formula (I).

In the formula (I), n represents an integer of 2 to 6, from the viewpoint of flexibility after the radiation curable composition is cured, adhesion to a support such as a recording medium, and availability of raw materials. , N is preferably an integer of 3 to 5, more preferably n is 3 or 5, and particularly preferably n is 5, that is, N-vinylcaprolactam. N-Vinylcaprolactam is preferable because it is excellent in safety, is generally available and can be obtained at a relatively low price, and provides particularly good curability and adhesion of a cured film to a support.
The N-vinyl lactams may have a substituent such as an alkyl group or an aryl group on the lactam ring, and may be linked with a saturated or unsaturated ring structure.

The radiation curable composition of the present invention preferably contains N-vinyl lactams in an amount of 15% by weight or more based on the total weight of the radiation curable composition. When the content of the N-vinyl lactam is 15% by weight or more, a radiation curable composition excellent in sufficient curability, cured film flexibility, and substrate adhesion of the cured film can be obtained. The more preferable content of the N-vinyl lactam in the radiation curable composition is in the range of 15% by weight to 35% by weight, and the particularly preferable content is 18% by weight to 30% by weight. It is a range.
N-vinyl lactams are compounds having a relatively high melting point. A radiation curable composition having a content of N-vinyl lactam of 40% by weight or less is preferable because it exhibits good solubility even at a low temperature of 0 ° C. or less, and the temperature range in which the radiation curable composition can be handled becomes wide.

  The N-vinyl lactams may be contained in the radiation curable composition only in one kind or in plural kinds. When a plurality of N-vinyl lactams are contained, the radiation curable composition of the present invention has a total amount of N-vinyl lactams of 15% by weight or more of N- with respect to the total weight of the radiation curable composition. It is preferable to contain vinyl lactams.

  In the present invention, oligomers and polymers can be used together. Here, an oligomer means a compound having a molecular weight (weight average molecular weight for those having a molecular weight distribution) of 2,000 or more, and a polymer has a molecular weight (weight average molecular weight for those having a molecular weight distribution) of 10. Means more than 1,000 compounds. The oligomer or polymer may not have a radical polymerizable group, but preferably has a radical polymerizable group. It is preferable that the radical polymerizable group in one molecule of the oligomer or polymer is 1 or more and 4 or less on average because a radiation-curable composition having excellent flexibility can be obtained. Oligomer and polymer can be added in an appropriate amount to adjust the radiation curable composition to an optimum viscosity for ejection.

  The content of the radically polymerizable compound in the radiation curable composition of the present invention is preferably 50 to 95% by weight, more preferably 60 to 95% by weight, based on the total solid content in the radiation curable composition, 65 More preferred is ˜95% by weight.

The radiation-curable composition of the present invention can contain monofunctional and polyfunctional polymerizable compounds as radically polymerizable compounds. Here, the “monofunctional polymerizable compound” and the “polyfunctional polymerizable compound” are respectively a polymerizable compound having only one polymerizable residue in the molecule, and 2 polymerizable residues in the molecule. A polymerizable compound having two or more.
The ratio of the monofunctional polymerizable compound in the radical polymerizable compound is preferably 95% by weight or more, more preferably 95 to 100% by weight, and 97 to 100% by weight based on the total weight of the radical polymerizable compound. % Is more preferable. Within the above range, the heat stretchability of the cured film after photopolymerization can be made excellent.
As the monofunctional ethylenically unsaturated polymerizable compound, a compound selected from the group consisting of monofunctional (meth) acrylates, monofunctional vinyloxy compounds, monofunctional N-vinyl compounds and monofunctional (meth) acrylamides is preferably used. it can.
More preferably, the monofunctional ethylenically unsaturated polymerizable compound contains 65% by weight or more of N-vinyl lactams and monofunctional (meth) acrylates. Monofunctional (meth) acrylates include (meth) acrylates having an alicyclic residue selected from a norbornyl structure, isobornyl structure, dicyclopentanyl structure, dicyclopentenyl structure or adamantyl structure, phenoxyethyl (meth) Acrylate is particularly preferably used.

(Component B) Polymerization initiator The radiation-curable composition of the present invention contains (Component B) a polymerization initiator.
As the polymerization initiator that can be used in the present invention, a known radical polymerization initiator can be used. The radical polymerization initiator that can be used in the present invention may be used alone or in combination of two or more.
The polymerization initiator that can be used in the present invention is a compound that absorbs external energy and generates a polymerization initiating species. External energy used for initiating polymerization is roughly divided into heat and actinic radiation, and a thermal polymerization initiator and a photopolymerization initiator are used, respectively. Examples of the active radiation include γ rays, β rays, electron beams, ultraviolet rays, visible rays, and infrared rays.

  The radical polymerization initiator that can be used in the present invention includes (a) aromatic ketones, (b) acylphosphine compounds, (c) aromatic onium salt compounds, (d) organic peroxides, and (e) thio compounds. (F) hexaarylbiimidazole compound, (g) ketoxime ester compound, (h) borate compound, (i) azinium compound, (j) metallocene compound, (k) active ester compound, and (l) carbon halogen Examples thereof include a compound having a bond. These radical polymerization initiators may be used alone or in combination with the above compounds (a) to (l).

  Preferable examples of (a) aromatic ketones and (e) thio compounds include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” P. FOUASSIER J.M. F. RABEK (1993), pp. Examples include compounds having a benzophenone skeleton or a thioxanthone skeleton described in 77-117. More preferable examples of (a) aromatic ketones, (b) acylphosphine compounds, and (e) thio compounds include α-thiobenzophenone compounds described in JP-B 47-6416, JP-B 47- Benzoin ether compounds described in Japanese Patent No. 3981, α-substituted benzoin compounds described in Japanese Patent Publication No. 47-22326, benzoin derivatives described in Japanese Patent Publication No. 47-23664, and aroylphosphonic acids described in Japanese Patent Publication No. 57-30704. Esters, dialkoxybenzophenones described in JP-B-60-26483, benzoin ethers described in JP-B-60-26403, JP-A-62-81345, JP-B-1-34242, US Pat. No. 318,791 and European Patent No. 0284561A1 described in α-aminobenzofe , P-di (dimethylaminobenzoyl) benzene described in JP-A-2-211452, thio-substituted aromatic ketone described in JP-A-61-194062, acylphosphine sulfide described in JP-B-2-9597 And acylphosphine described in JP-B-2-9596, thioxanthones described in JP-B-63-61950, and coumarins described in JP-B-59-42864.

  Examples of the benzophenone compound include benzophenone, 4-phenylbenzophenone, isophthalophenone, 4-benzoyl-4'-methylphenyl sulfide and the like. Examples of the thioxanthone compound include 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone and the like.

In addition, (a) aromatic ketones are preferably α-hydroxy ketones such as 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one. 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxycyclohexyl phenyl ketone and the like.
Among these, as (a) aromatic ketones, a 1-hydroxycyclohexyl phenyl ketone compound is particularly preferable. In the present invention, the 1-hydroxycyclohexyl phenyl ketone compound means a compound in which 1-hydroxycyclohexyl phenyl ketone and 1-hydroxycyclohexyl phenyl ketone are substituted with an arbitrary substituent. The substituent can be arbitrarily selected as long as it can exhibit the ability as a radical polymerization initiator, and specifically, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, etc.) is exemplified. it can.

Further, as the (b) acylphosphine compound, an acylphosphine oxide compound is preferable.
Examples of the acylphosphine oxide compound include those having the structural formula of formula (7) or formula (8) in the structure of the compound.

  In particular, as the acylphosphine oxide compound, those having a chemical structure of the formula (9) or the formula (10) are particularly preferable.

（式中、Ｒ⁶、Ｒ⁷、Ｒ⁸はメチル基又はエチル基を置換基として有していてもよい芳香族炭化水素基を表す。）

(In the formula, R ⁶ , R ⁷ and R ⁸ represent an aromatic hydrocarbon group which may have a methyl group or an ethyl group as a substituent.)

（式中、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹はメチル基又はエチル基を置換基として有していてもよい芳香族炭化水素基を表す。）

(In formula, R < ⁹ >, R < ¹⁰ >, R < ¹¹ > represents the aromatic hydrocarbon group which may have a methyl group or an ethyl group as a substituent.)

  As the acylphosphine oxide compound, a monoacylphosphine oxide compound, a bisacylphosphine oxide compound, or the like can be used. As the monoacylphosphine oxide compound, a known monoacylphosphine oxide compound can be used. Examples thereof include monoacylphosphine oxide compounds described in JP-B-60-8047 and JP-B-63-40799. Specific examples include isobutyrylmethylphosphinic acid methyl ester, isobutyrylphenylphosphinic acid methyl ester, pivaloylphenylphosphinic acid methyl ester, 2-ethylhexanoylphenylphosphinic acid methyl ester, pivaloylphenylphosphinic acid isopropyl Ester, p-toluylphenylphosphinic acid methyl ester, o-toluylphenylphosphinic acid methyl ester, 2,4-dimethylbenzoylphenylphosphinic acid methyl ester, pt-butylbenzoylphenylphosphinic acid isopropyl ester, acryloylphenylphosphinic acid methyl ester , Isobutyryl diphenyl phosphine oxide, 2-ethylhexanoyl diphenyl phosphine oxide, o-toluyl diphenyl phosphite Oxide, pt-butylbenzoyldiphenylphosphine oxide, 3-pyridylcarbonyldiphenylphosphine oxide, acryloyl-diphenylphosphine oxide, benzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid vinyl ester, adipoylbisdiphenylphosphine oxide, pivaloyl Diphenylphosphine oxide, p-toluyldiphenylphosphine oxide, 4- (t-butyl) benzoyldiphenylphosphine oxide, terephthaloylbisdiphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, versatoyldiphenylphosphine oxide, 2-methyl-2 -Ethylhexanoyldiphenylphosphine oxide, 1- Chill - cyclohexanoyl diphenylphosphine oxide, pivaloyl phenyl phosphinic acid methyl ester and pivaloyl phenyl phosphinic acid isopropyl ester.

  A known bisacylphosphine oxide compound can be used as the bisacylphosphine oxide compound. Examples thereof include bisacylphosphine oxide compounds described in JP-A-3-101686, JP-A-5-345790, and JP-A-6-298818. Specific examples include bis (2,6-dichlorobenzoyl) phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-ethoxy. Phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2-naphthylphosphine oxide, bis (2,6-dichlorobenzoyl) -1-naphthyl Phosphine oxide, bis (2,6-dichlorobenzoyl) -4-chlorophenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,4-dimethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) decylphosphite Oxide, bis (2,6-dichlorobenzoyl) -4-octylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,5- Dimethylphenylphosphine oxide, bis (2,6-dichloro3,4,5-trimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichloro-3,4,5-trimethoxybenzoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2- Methyl-1-naphthoyl) -2-naphthy Phosphine oxide, bis (2-methyl-1-naphthoyl) -4-propylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methoxy-1-naphthoyl) ) -4-engineered phenylphenylphosphine oxide, bis (2-chloro-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide Etc.

  Among these, in the present invention, as the acylphosphine oxide compound, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE 819: manufactured by Ciba Specialty Chemicals), bis (2,6-dimethoxybenzoyl) ) -2,4,4-trimethylpentylphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (DAROCUR TPO: manufactured by Ciba Specialty Chemicals, LUCIRIN TPO: manufactured by BASF) and the like are preferable.

  (C) As aromatic onium salt compounds, elements of Groups 15, 16 and 17 of the periodic table, specifically N, P, As, Sb, Bi, O, S, Se, Te, or I fragrances Group onium salts are included. For example, iodonium salts described in European Patent No. 104143, US Pat. No. 4,837,124, Japanese Patent Laid-Open No. 2-150848, Japanese Patent Laid-Open No. 2-96514, European Patent Nos. 370693, 233567, and 297443 are disclosed. The diazonium salts described in the specifications of U.S. Pat. Nos. 2,974,279, 279210, and 422570, U.S. Pat. Nos. 3,902,144, 4,933,377, 4,760013, 4,734,444, and 2,833,827. Benzenediazonium which may have a substituent), diazonium salt resins (formaldehyde resin of diazodiphenylamine, etc.), N-alkoxypyridinium salts, etc. (for example, US Pat. No. 4,743,528, JP-A-63) -138345, JP-A-63 142345, JP-A-63-142346, and JP-B-46-42363, specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate, etc. The compounds described in JP-A 52-147277, 52-14278, and 52-14279 are preferably used. Generates radicals and acids as active species.

  (D) The organic peroxide includes almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. Examples thereof include 3,3 ′, 4,4′-tetra (t -Butylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra (t-amylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t-octylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (cumylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′- Peroxide compounds such as tetra (p-isopropylcumylperoxycarbonyl) benzophenone and di-t-butyldiperoxyisophthalate are preferred. .

  (F) Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) ) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxyphenyl) biimidazole, 2 , 2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5 ' Tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 Examples include ', 5,5'-tetraphenylbiimidazole.

  (G) Examples of the ketoxime ester compound include 3-benzoyloxyiminobutane-2-one, 3-acetoxyiminobutane-2-one, 3-propionyloxyiminobutane-2-one, and 2-acetoxyiminopentane-3. -One, 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-p-toluenesulfonyloxyiminotan-2-one, 2-ethoxy And carbonyloxyimino-1-phenylpropan-1-one.

  (H) Examples of the borate compound include compounds described in US Pat. Nos. 3,567,453, 4,343,891, European Patents 109,772, and 109,773. Can be mentioned.

  (I) Examples of azinium compounds include those disclosed in JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46-42363. The compound group which has NO bond of each gazette description can be mentioned.

  (J) Examples of metallocene compounds include titanocenes described in JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, and JP-A-2-4705. Examples thereof include iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109.

  Specific examples of the titanocene compound include di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, and di-cyclopentadienyl-Ti-bis-2,3. 4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti- Bis-2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4 -Difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti- -2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyridin-1-yl) phenyl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (methylsulfonamido) phenyl] titanium, bis (cyclopenta And dienyl) bis [2,6-difluoro-3- (N-butylbialoylamino) phenyl] titanium.

  (K) Examples of the active ester compound include the specifications of European Patent Nos. 0290750, 046083, 156153, 271851, and 0388343, U.S. Pat. Nos. 3,901,710, and 4,181,531. Nitrobenzol ester compounds described in JP-A-60-198538 and JP-A-53-133022, European Patents 0199672, 84515, 199672, 0441115, and 0101122. No. 4,618,564, U.S. Pat. No. 4,371,605 and U.S. Pat. No. 4,431,774, and JP-A 64-18143, JP-A-2-245756, and JP-A-4-365048. Sulfonate compounds, JP-B-62-2223, JP-B-63- No. 4340, and compounds, and the like described in the JP-A No. 59-174831.

  (L) Preferable examples of the compound having a carbon halogen bond include, for example, compounds described in Wakabayashi et al., Bull. Chem. Soc. Japan, 42, 2924 (1969), compounds described in British Patent No. 1388492, Examples thereof include compounds described in Japanese Utility Model Publication No. 53-133428, compounds described in German Patent No. 3337024, and the like.

  Further, compounds described in J. Org. Chem., 29, 1527 (1964) by FC Schaefer et al., Compounds described in JP-A-62-258241, compounds described in JP-A-5-281728, and the like can be mentioned. it can. A compound as described in German Patent 2,641,100, a compound described in German Patent 3,333,450, a compound group as described in German Patent No. 3021590, or a compound group as described in German Patent No. 3021599, Etc.

  The radiation curable composition of the present invention preferably contains an acylphosphine oxide compound, more preferably an acylphosphine compound and a benzophenone compound or an α-aminoketone compound are used in combination, and the acylphosphine compound and the benzophenone compound are combined. It is more preferable to use together. When the combination is used, a radiation curable composition having excellent curability and blocking resistance can be obtained.

In the radiation curable composition that can be used in the present invention, the total use amount of the radical polymerization initiator is preferably 0.01 to 35% by weight, more preferably relative to the total use amount of the polymerizable compound. It is in the range of 0.5 to 20% by weight, more preferably 1.0 to 15% by weight. When the content is 0.01% by weight or more, the composition can be sufficiently cured, and when it is 35% by weight or less, a cured film having a uniform degree of curing can be obtained.
Moreover, when using the sensitizer mentioned later for the radiation curable composition which can be used for this invention, the total usage-amount of a radical polymerization initiator is a radical polymerization initiator: sensitization with respect to a sensitizer, respectively. The weight ratio of the agent is preferably 200: 1 to 1: 200, more preferably 50: 1 to 1:50, and still more preferably 20: 1 to 1: 5.

(Component C) A polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group. The radiation-curable composition of the present invention includes the radical polymerizable compound as an essential component and In addition to the polymerization initiator, (Component C) a polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group (hereinafter also referred to as “surface segregation polymer”) .).
The surface segregation polymer is unevenly distributed on the surface of the cured film of the radiation curable composition, thereby suppressing leaching and blocking of residual monomers and volatile components in the radiation curable composition.
Examples of the surface segregation polymer include polymers having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group in the side chain as an example having a partial structure in the side chain. As another example, a side chain of a main chain structure including a urethane bond or a urea bond is selected from a polymerizable group, a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group. And a polymerizable polymer having at least one partial structure. Hereinafter, these surface segregation polymers will be described in detail.

The surface segregation polymer is a polymer containing in its side chain a partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group.
Hereinafter, the partial structures 1) to 3) will be described.

[1] Fluorine-substituted hydrocarbon group]
The fluorine-substituted hydrocarbon group in the surface segregation polymer in the present invention may be a hydrocarbon group substituted with at least one fluorine atom. For example, at least one hydrogen atom in an alkyl group or an alkylene group may be a fluorine atom. A substituted fluoroalkyl group and a fluoroalkylene group can be mentioned, and a perfluoroalkyl group and a perfluoroalkylene group in which all hydrogens of the alkyl group and the alkylene group are substituted with fluorine are more preferable, and a perfluoroalkyl group is still more preferable.

As an alkyl group, C3-C12 is preferable, C4-C10 is more preferable, and C6-C8 is still more preferable.
As an alkylene group, C2-C12 is preferable, C4-C10 is more preferable, and C6-C8 is still more preferable.

Specific embodiments of the fluorine-substituted hydrocarbon group in the present invention will be described.
Preferred fluorine-substituted hydrocarbon groups possessed by the surface segregation polymer include those shown in the following (A) or (B).
(A) A substituent derived from a fluoroaliphatic compound produced by a telomerization method or an oligomerization method (hereinafter, appropriately referred to as “fluoroaliphatic group”)
(B) Substituent represented by the following (general formula I)

In the above (general formula I), R ² and R ³ are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, X is a covalent bond or a divalent linking group (organic group), and m is 0 or more. N represents an integer of 1 or more.
When m is 2 or more, functional groups on adjacent carbons (that is, R ² and R ³ bonded to adjacent carbons) may be bonded to form an aliphatic ring. .
The substituent represented by (general formula I) is connected to the polymer main chain at the portion *.

(A) Substituent derived from fluoroaliphatic compound produced by telomerization method or oligomerization method The fluorine-substituted hydrocarbon group in the present invention is a telomerization method (also called telomer method) or oligomerization. A substituent (fluoroaliphatic group) derived from a fluoroaliphatic compound produced by the method (also referred to as oligomer method) is preferred.
With regard to a method for producing such a fluoroaliphatic group, for example, “Synthesis and Function of Fluorine Compound” (Supervision: Nobuo Ishikawa, published by CMC Co., 1987), “Chemistry of Organic” Fluorine Compounds II "(Monograph 187, Ed by Milos Hudricky and Attila E. Pavlath, American Chemical Society 1995), pages 747-752.

  The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen.

In the present invention, the fluoroaliphatic compound synthesized by the telomer method is preferably a fluoroaliphatic compound represented by the following general formula [TM-1].
By using such a fluoroaliphatic compound as it is or converted into a desired monomer structure, it can be introduced into the fluorine-substituted hydrocarbon group in the surface segregation polymer in the present invention.

In the above general formula [TM-1], T is one group selected from the following (Group T), Z is one group selected from the following (Group Z), and n is an integer of 0 to 20. To express.
When the fluoroaliphatic compound represented by the general formula [TM-1] has a polymerizable group such as a double bond in Z, it should be used as a copolymerization component when synthesizing the surface segregation polymer in the present invention. Can do.

  In the above general formula [TM-1], when the group represented by Z is one group selected from the following (Group Z ′), a structure having an acryloyl group or a methacryloyl group at the molecular terminal Become. For this reason, since the surface segregation polymer in this invention is obtained from the fluoro aliphatic compound represented by general formula [TM-1] simply by vinyl polymerization, it is especially preferable.

  Specific examples of the compound produced by the telomer method, which is preferably used when synthesizing the surface segregation polymer in the present invention (commercially available based on a fluoroaliphatic compound represented by the general formula [TM-1]) Products), for example, fluorine chemical products sold by Daikin Chemicals Sales Co., Ltd., and CHEMINOX FA, FA-M, FAAC, FAAC- manufactured by Nippon Mektron Co., Ltd. M, FAMAC, FAMAC-M and the like.

  The fluoroaliphatic compound produced by the telomer method can easily synthesize a polymer having a fluoroaliphatic group in the side chain, such as the surface segregation polymer in the present invention, by a method known to those skilled in the art. .

In the present invention, a substituent derived from a fluoroaliphatic compound produced by an oligomerization method (oligomer method) is also preferred.
The oligomerization method is a method for producing an oligomer by cationic polymerization of tetrafluoroethylene in a polar solvent such as diglyme using potassium fluoride or cesium fluoride as a catalyst. As a specific example, Synthesis Example 1 below is shown.
Fluoroaliphatic compounds obtained by the oligomer method, like the compounds by the telomer method described above, use a polymerizable group (unsaturated bond) in the oligomer obtained by cationic polymerization, and if necessary, appropriate chemical modification Then, a polymer having a substituent (fluorine-containing hydrocarbon group) derived from the fluoroaliphatic compound in the side chain can be synthesized.

(B) Substituent Represented by (General Formula I) The surface segregation polymer in the present invention has a substituent represented by the following (general formula I) from the viewpoint of uneven distribution on the surface of the cured film (ink surface). It is preferable to have.

In the above (general formula I), R ² and R ³ are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, * is a linking site to the polymer main chain, and X is a covalent bond or a divalent linking group. , M represents an integer of 0 or more, and n represents an integer of 1 or more.
When m is 2 or more, functional groups on adjacent carbons (that is, R ² and R ³ bonded to adjacent carbons) may be bonded to form an aliphatic ring. .

  Among the substituents represented by the above (General Formula I), those in which “n” in (General Formula I) is 1 to 10 are preferable, 1 to 4 are more preferable, 2 or 3 It is particularly preferred that

  That is, as the surface segregation polymer in the present invention, the structure of the side chain portion bonded to the polymer main chain is a structure represented by the following (general formula IB), and in particular, n = 2, 3, It is preferable because it exhibits very good performance.

In the above (formula ^{IB), R 2, R 3} , X, m, and n have the same meanings as ^{R 2, R 3, X,} m, and n in both (general formula I).

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ² and R ³ in (General Formula I) and (General Formula IB) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a tert-butyl group, etc. are mentioned, Preferably they are a hydrogen atom or a methyl group, More preferably, it is a hydrogen atom.

In (General Formula I) and (General Formula IB), when X is a covalent bond, it means that the polymer main chain and the carbon atom to which R ² and R ³ are bonded are directly connected. To do.
When X is a divalent linking group, examples of the linking group include —O—, —S—, —N (R ⁴ ) —, —CO—, and the like. Among these, -O- is more preferable.
Here, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group, and a hydrogen atom and a methyl group are preferable.

In (General Formula I) and (General Formula IB), m represents an integer of 0 or more, preferably an integer of 2 to 8, and particularly preferably 2. When m is 2 or more, functional groups on adjacent carbons (that is, R ² and R ³ bonded to adjacent carbons) may be bonded to form an aliphatic ring. .

  In (General Formula I) and (General Formula IB), n represents an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 4, and particularly preferably 2 or 3.

In (General Formula I), * represents a linking site with a polymer main chain, and specific examples of the polymer main chain include the following examples.
For example, acrylic resin, methacrylic resin, styryl resin, polyester resin, polyurethane resin, polycarbonate resin, polyamide resin, polyacetal resin, phenol / formaldehyde condensation resin, polyvinylphenol resin, maleic anhydride / α-olefin resin, α-hetero substituted A methacrylic resin or the like can be used. Among these, acrylic resins, methacrylic resins, styryl resins, polyester resins, and polyurethane resins are useful, and acrylic resins, methacrylic resins, and polyurethane resins are particularly useful.

  The surface segregation polymer having 1) a fluorine-substituted hydrocarbon group in the present invention has, for example, the above-mentioned monomer (A) having a fluoroaliphatic group or (B) the substituent represented by the above (general formula I). A monomer (that is, a monomer having a fluorine-substituted hydrocarbon group) is appropriately selected and used, and can be easily obtained by methods known to those skilled in the art, such as condensation polymerization, addition polymerization, and ring-opening polymerization. Further, these monomers may be mixed as necessary.

(Monomer having a fluorine-substituted hydrocarbon group)
In the present invention, as described above, it is preferable to obtain a surface segregation polymer by using a monomer having a fluorine-substituted hydrocarbon group (hereinafter referred to as a fluorine-substituted hydrocarbon group-containing monomer).
Preferred examples of the fluorine-substituted hydrocarbon group-containing monomer include monomers represented by the following (General Formula II).

In (General Formula II), R ¹ represents a hydrogen atom, a halogen atom, an optionally substituted methyl group, or an optionally substituted ethyl group. R ² , R ³ , X, m, and n are all synonymous with R ² , R ³ , X, m, and n in (General Formula I), and preferred examples are also the same.

In addition, examples of the halogen atom represented by R ¹ in (General Formula II) include a fluorine atom, a chlorine atom, and a bromine atom.

  Specific examples of the monomer represented by the above (General Formula II) used in the present invention are shown below.

  As a monomer used for the synthesis of the surface segregation polymer in the present invention, among the monomers represented by the above (General Formula II), “n” in (General Formula II) is preferably 1 to 10, and 1 to 4 Is more preferable, and 2 or 3 is particularly preferable.

[2] Siloxane skeleton
The siloxane skeleton contained in the surface segregation polymer in the present invention is not particularly limited as long as it has “—Si—O—Si—”.
In the present invention, as the surface segregation polymer having a siloxane skeleton, from the viewpoint of increasing the discharge stability of the radiation curable composition and increasing the surface segregation property when the radiation curable composition is used as a coating film, A compound including a structural unit having a siloxane skeleton is preferable.

A siloxane compound useful for introducing a siloxane skeleton into the molecule of the surface segregation polymer can be obtained as a commercial product. For example, X-22-173DX, X-22-173BX manufactured by Shin-Etsu Chemical Co., Ltd. One-terminal reactive silicones such as
Further, it can be synthesized by reacting a siloxane having a reactive end with a compound having a cationic polymerizable group. For example, it is synthesized from a compound having a single-terminal hydroxyl group such as Silaplane series FM-0411, FM-0421, FM-0425 manufactured by Chisso Corporation and epichlorohydrin, or disclosed in JP-A-11-80315. It can be synthesized by the method described.
Examples of the siloxane skeleton according to the present invention include, but are not limited to, the structures shown below.

[3] Long chain alkyl group]
The 3) long-chain alkyl group contained in the surface segregation polymer in the present invention is preferably an alkyl group having 6 or more carbon atoms, which may be linear, branched or cyclic, but more linear. preferable. Preferably carbon number is 6-40, More preferably, it is 6-18, More preferably, it is 6-12.

The alkyl group having at least 6 carbon atoms present on the side chain in the surface-segregating polymer is a substituent represented by -C _n H _{2n + 1} in the following general formula (III), represented by the general formula (III) It is preferably introduced into the polymer by including a structural unit.

In general formula (III), n represents an integer of 6 to 40, preferably 6 to 18, and more preferably 6 to 12 from the viewpoint of segregation.
Y represents a polymer main chain, and —C _n H _{2n + 1} (an alkyl group having 6 or more carbon atoms) is bonded to the main chain directly or via a linking group.
W represents a single bond or a linking group. When a single bond is represented, a long-chain alkyl group is directly bonded to the polymer main chain. Z ¹ represents a hydrogen atom or a monovalent substituent.

The structural unit may have a plurality of alkyl groups having 6 or more carbon atoms in the general formula (III). In that case, an alkyl group having 6 or more carbon atoms is bonded to the position of Z ¹ through a linking group W. And a mode in which the linking group W has a branched structure or a ring structure, and another alkyl group having 6 or more carbon atoms is linked to the tip of any carbon atom constituting the W.
Examples of W include linear or branched alkylene having 1 to 20 carbon atoms, linear or cyclic alkylene, linear or branched alkenylene having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, and carbon number 6 -20 arylene (monocyclic, heterocyclic), -OC (= O)-, -OC (= O) Ar-, -OC (= O) O-, -OC (= O) OAr-, -C ( = O) NR -, - C (= O) NAr -, - SO 2 NR -, - SO 2 NAr -, - O- ( alkyleneoxy, polyalkyleneoxy), - OAr- aryleneoxy, polyarylene oxy) —C (═O) O—, —C (═O) O—Ar—, —C (═O) Ar—, —C (═O) —, —SO ₂ O—, —SO ₂ OAr—, — _{OSO 2 -, - OSO 2 Ar} -, - NRSO 2 -, - NArSO 2 -, - NRC (= O) -, NArC (= O)-, -NRC (= O) O-, -NArC (= O) O-, -OC (= O) NR-, -OC (= O) NAr-, -NAr-, -NR- , -N + RR'-, -N + RAr-, -N + ArAr'-, -S-, -SAr-, -ArS-, a heterocyclic group (including heteroatoms such as nitrogen, oxygen, and sulfur, 3- to 12-membered monocyclic or condensed ring), -OC (= S)-, -OC (= S) Ar-, -C (= S) O-, -C (= S) OAr-, -C (= S) OAr-, -C (= O) S-, -C (= O) SAr-, -ArC (= O)-, -ArC (= O) NR-, -ArC (= O) NAr- , -ArC (= O) O-, -ArC (= O) O-, -ArC (= O) S-, -ArC (= S) O-, -ArO-, -ArNR- and the like. Can be mentioned.
R and R ′ are a hydrogen atom, a linear or branched alkyl group, a chain or cyclic alkyl group, a linear or branched alkenyl group, a chain or cyclic alkenyl group, a linear or branched alkynyl group. Represents a group, a chain or cyclic alkynyl group, and Ar and Ar ′ represent an aryl group.

  Among these linking groups, arylene having 6 to 20 carbon atoms (monocyclic, heterocyclic), -C (= O) NR-, -C (= O) NAr-, -O- (alkyleneoxy, polyalkyleneoxy) ), -OAr- (aryleneoxy, polyaryleneoxy), -C (= O) O-, -C (= O) O-Ar-, -C (= O)-, -C (= O) Ar- , -S-, -SAr-, -ArS-, -ArC (= O)-, -ArC (= O) O-, -ArC (= O) O-, -ArO-, -ArNR- and the like are preferable. Arylene (monocyclic, heterocyclic) having 6 to 20 carbon atoms, —C (═O) NR—, —C (═O) NAr—, —O— (alkyleneoxy, polyalkyleneoxy), —OAr— (arylene) Oxy, polyaryleneoxy), -C (= O) O-, -C (= O) O-Ar-, -SAr , -ArS -, - ArC (= O) -, - ArC (= O) O -, - ArC (= O) O -, - ArO -, - ArNR- are more preferable.

In the present invention, the linking group represented by W may be a combination of two or more of the linking groups listed here.
Specific examples of such a divalent substituent represented by W are shown below in particular from the viewpoint of segregation on the ink surface, but the present invention is not limited thereto.

Z ¹ is preferably exemplified by the following groups in addition to the mode in which a long-chain alkyl group is bonded via the linking group W. Here, when m is 6 or more and 20 or less, it is possible to have a long-chain alkyl group in such a manner.

  Here, although the specific example of the structural unit which has the long-chain alkyl group which comprises the surface segregation polymer in this invention is given below, this invention is not limited to these.

In the present invention, the content in the surface segregation polymer of the partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group is 3 to 60% by weight, respectively. It is preferably 3 to 50% by weight, more preferably 5 to 40% by weight.
By setting it as the said range, a surface segregation polymer can be efficiently surface-segregated within a radiation-curable composition.

  In addition, the total content of specific sites in the case of containing two or more partial structures selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group depends on the surface segregation polymer. On the other hand, it is 3 to 60% by weight, more preferably 3 to 50% by weight, and still more preferably 5 to 40% by weight.

  The content of the partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group in the total solid content of the radiation curable composition in the present invention is 0. 1 to 20% by weight is preferable, more preferably 0.5 to 15% by weight, and still more preferably 1 to 10% by weight. By setting it as the said range, it is excellent in surface curability and blocking suppression, and the surface tension (22 mN / m-28 mN / m) and moderate viscosity which can be discharged are obtained.

[Radically polymerizable group]
The surface segregation polymer in the present invention may have a radical polymerizable group in the side chain.
When the surface segregation polymer contains a radical polymerizable group, the cured film surface of the radiation curable composition can be more firmly coated with the polymer. Therefore, even if a volatile component remains in the cured film, it is possible to prevent exudation and elution from the cured film, and as a result, the stickiness of the substrate surface on which the image is printed is suppressed, and the blocking property is reduced. Improve.
This is because when a film is formed by applying a radiation curable composition to a substrate, the surface segregation polymer is unevenly distributed on the film surface, and the polymerizable group of the surface segregation polymer is polymerized, whereby the film surface is It is thought that it is covered with a cured surface segregation polymer.

Examples of the radical polymerizable group include a polymerizable group having an ethylenically unsaturated bond capable of radical polymerization.
Examples of polymerizable groups having an ethylenically unsaturated bond capable of radical polymerization include acrylic acid ester groups, methacrylic acid ester groups, itaconic acid ester groups, crotonic acid ester groups, isocrotonic acid ester groups, and maleic acid ester groups. Examples thereof include radically polymerizable groups such as unsaturated carboxylic acid ester groups and styrene groups. Among these, a methacrylic acid ester group and an acrylic acid ester group are preferable.

  The content of the radical polymerizable group is preferably 5 to 90 mol%, more preferably 5 to 85 mol%, and still more preferably 10 to 80 mol% in the surface segregation polymer.

As a method for introducing a radically polymerizable group into a surface segregation polymer, a monomer in which a double bond of a radically polymerizable group is used to seal a reaction with a protecting group is copolymerized to remove the protecting group. And a method of introducing a radically polymerizable group (double bond) and a method of introducing a low molecular compound having a radically polymerizable group into a surface segregation polymer by a polymer reaction.
Specific examples of the radical polymerizable group are shown below. The present invention is not limited to these specific examples.

The surface segregation polymer in the present invention is a copolymer having a partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group, and a structure other than a radical polymerizable group. A component (other copolymerization component) may be included. The other copolymer component is preferably used in the surface segregation polymer from the viewpoint of improving the solubility in the radiation curable composition and improving the blocking property by controlling the polymer Tg.
The other copolymerization component is not particularly limited as long as it is derived from a radically polymerizable monomer. However, from the viewpoint of copolymerization performance and solubility of the produced polymer in the radiation curable composition, an unsaturated double bond is formed. Among these monomers, acrylate or methacrylate is preferable. The preferable content of other copolymerization components in the surface segregation polymer is 0 to 70 mol%, more preferably 0 to 50 mol%, and most preferably 0 to 30 mol%.

Here, the preferable aspect as a main chain structure of the surface segregation polymer contained in the radiation-curable composition of the present invention is a methacrylic resin or an acrylic resin.
In addition, the main chain structure of the surface segregation polymer is preferably synthesized by radical chain polymerization, and the main chain structure is a polymer containing a urethane structure or a urea structure as a repeating unit. Is also a preferred embodiment.

  The weight average molecular weight of the surface segregation polymer is preferably 5,000 to 200,000, more preferably 5,000 to 100,000, and still more preferably 5,000 to 80,000. By setting it as the said range, moderate viscosity is obtained and it is favorable from a sclerosing | hardenable viewpoint.

  Preferable specific examples of the surface segregation polymer in the present invention include surface segregation polymers described in paragraphs 0108 to 0116 of JP 2010-018728 A.

  A commercially available product may be used as the surface segregation polymer, for example, BYK-UV3500 (polydimethylsiloxane having a polyether-modified acrylic group), BYK-UV3510 (polyether-modified polydimethylsiloxane), BYK- manufactured by BYK Chemie. UV3570 (polydimethylsiloxane having a polyester-modified acrylic group) and the like.

  The content of the surface segregation polymer contained in the radiation curable composition of the present invention is preferably 0.03 to 5% by weight, more preferably 0.1 to 4% by weight in the total solid content of the radiation curable composition. 0.5 to 2% by weight is more preferable.

(Component D) Colorant The radiation curable composition of the present invention is preferably an ink composition, and preferably contains a colorant in order to improve the visibility of the formed image portion.
The colorant that can be used in the present invention is not particularly limited, but pigments and oil-soluble dyes that are excellent in weather resistance and excellent in color reproducibility are preferable, and are arbitrarily selected from known colorants such as soluble dyes. Can be used. The colorant that can be suitably used in the radiation curable composition of the present invention is selected from compounds that do not function as a polymerization inhibitor in a polymerization reaction that is a curing reaction, from the viewpoint of not reducing the sensitivity of the curing reaction by active radiation. It is preferable.

Although it does not necessarily limit as a pigment which can be used for this invention, For example, the organic or inorganic pigment of the following number described in a color index can be used.
Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 42, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, 53. : 1, 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144 , 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13, 16, 20, 36,
Pigment Blue 1,15,15: 1,15: 2,15: 3,15: 4,15: 6,16,17-1,22,27,28,29,36,60 as a blue or cyan pigment ,
As a green pigment, Pigment Green 7, 26, 36, 50,
As yellow pigments, Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 120, 137 , 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193,
As the black pigment, Pigment Black 7, 28, 26,
As a white pigment, Pigment White 6, 18, 21
Etc. can be used according to the purpose.

In the present invention, a disperse dye can be used as long as it is soluble in a water-immiscible organic solvent. The disperse dye generally includes a water-soluble dye, but in the present invention, the disperse dye is preferably used as long as it is soluble in a water-immiscible organic solvent.
Preferable specific examples of the disperse dye include C.I. I. Disperse Yellow 5,42,54,64,79,82,83,93,99,100,119,122,124,126,160,184: 1,186,198,199,201,204,224 and 237 C. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54, 55, 66, 73, 118, 119 and 163; I. Disperse Red 54, 60, 72, 73, 86, 88, 91, 92, 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167: 1,177 , 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165: 1, 165: 2, 176, 183, 185, 197, 198, 201, 214, 224, 225 , 257, 266, 267, 287, 354, 358, 365 and 368; I. Disperse Green 6: 1 and 9;

  It is preferable that the colorant that can be used in the present invention is appropriately dispersed in the ink after being added to the radiation curable composition of the present invention. For dispersing the colorant, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, or a paint shaker can be used.

In the preparation of the radiation curable composition of the present invention, the colorant may be added by direct addition together with each component. However, in order to improve the dispersibility, a colorant such as a solvent or an addition polymerizable compound used in the present invention is used in advance. It can also be added after being added to the dispersion medium and uniformly dispersed or dissolved.
In the present invention, in order to avoid the deterioration of the solvent resistance when the solvent remains in the cured image and the problem of VOC (Volatile Organic Compound) of the remaining solvent, the colorant is an addition polymerizable compound. It is preferable to add and mix in advance in such a dispersion medium. In consideration of only dispersibility, it is preferable to select a monomer having the lowest viscosity as the polymerizable compound used for the addition of the colorant.

  These colorants may be used by appropriately selecting one type or two or more types according to the intended use of the radiation curable composition.

In addition, when using a colorant such as a pigment that remains solid in the radiation curable composition of the present invention, the average particle diameter of the colorant particles is preferably 0.005 to 0.5 μm, more preferably. Is preferably set to 0.01 to 0.45 [mu] m, more preferably 0.015 to 0.4 [mu] m, selection of colorant, dispersant, and dispersion medium, dispersion conditions, and filtration conditions. This particle size control is preferable because clogging of the head nozzle can be suppressed and the storage stability, transparency and curing sensitivity of the radiation curable composition can be maintained.
The content of the colorant in the radiation curable composition of the present invention is appropriately selected depending on the color and purpose of use, and is 0.01 to 30% by weight with respect to the weight of the entire radiation curable composition. Is preferred.

(Component E) Dispersant The radiation curable composition of the present invention preferably contains a dispersant. In particular, when a pigment is used, the dispersant is stably dispersed in the radiation curable composition. It is preferable to contain.
As the dispersant that can be used in the present invention, a polymer dispersant is preferable. The “polymer dispersing agent” in the present invention means a dispersing agent having a weight average molecular weight of 1,000 or more.

Examples of the polymer dispersant include DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-111, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-166, and DISPERBYK-166. , DISPERBYK-168, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-182 (manufactured by BYK Chemie); EFKA7462, EFKA7500, EFKA7570, EFKA7575, EFKA7580 (manufactured by Efka Additive); Disperse Aid 6, Disperse Aid 8, Disperse Aid 15, Disperse Aid 9100 (manufactured by Sannopco); Solsperse (SOLSPERSE) 3000 Various Solsperse dispersants (manufactured by Noveon) such as 5000, 9000, 12000, 13240, 13940, 17000, 22000, 24000, 26000, 28000, 32000, 36000, 39000, 41000, 71000; Adeka Pluronic L31, F38, L42, L44 , L61, L64, F68, L72, P95, F77, P84, F87, P94, L101, P103, F108, L121, -123 (manufactured by ADEKA Co., Ltd.), Ionette S-20 (manufactured by Sanyo Chemical Industries, Ltd.); Disparon KS-860, 873SN, 874 (polymer dispersant), # 2150 (aliphatic polycarboxylic acid), # 7004 (polyether ester type) (manufactured by Enomoto Kasei Co., Ltd.).
Although content of the dispersing agent in a radiation curable composition is suitably selected by the intended purpose, it is preferable that it is 0.05 to 15 weight% with respect to the weight of the whole radiation curable composition.

(Component F) Other components Other components other than the above components can be added to the radiation-curable composition of the present invention as necessary.
Examples of other components include sensitizers, co-sensitizers, surfactants, ultraviolet absorbers, polymerization inhibitors, antioxidants, anti-fading agents, conductive salts, solvents, polymer compounds, and basic compounds. Etc.
Sensitizers, co-sensitizers, surfactants, ultraviolet absorbers, polymerization inhibitors, antioxidants, antifading agents, conductive salts, solvents, polymer compounds, basic compounds that can be used in the present invention Are sensitizers, co-sensitizers, ultraviolet absorbers, polymerization inhibitors, antioxidants, antifading agents, conductive salts, solvents, etc. described in paragraphs 0135 to 0162 of JP2009-22214A The surfactants described in paragraph 0133 of the publication can be used, such as polymer compounds, basic compounds, and the like.

[Ink properties]
The radiation curable composition of the present invention can be suitably used as an ink composition.
In the present invention, in consideration of ejection properties, the viscosity at 25 ° C. of the radiation curable composition as the ink composition is preferably 40 mPa · s or less, more preferably 5 to 40 mPa · s, and 7 More preferably, it is -30 mPa * s.
Moreover, it is preferable that the viscosity in discharge temperature (Preferably 25-80 degreeC, More preferably, 25-50 degreeC) is 3-15 mPa * s, and it is more preferable that it is 3-13 mPa * s. It is preferable that the composition ratio of the ink composition of the present invention is appropriately adjusted so that the viscosity is in the above range. By setting the viscosity at room temperature high, even when a porous recording medium is used, penetration of the ink composition into the recording medium can be avoided and uncured monomers can be reduced. Furthermore, it is preferable because ink bleeding at the time of ink droplet landing can be suppressed, and as a result, the image quality is improved.

  The surface tension at 25 ° C. of the radiation curable composition as the ink composition is preferably 20 to 35 mN / m, and more preferably 23 to 33 mN / m. When recording on various recording media such as polyolefin, PET, coated paper, and non-coated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and 35 mN / m or less is preferable in terms of wettability.

(2) Cured film forming method and cured film The cured film forming method of the present invention is a composition applying step in which the radiation curable composition is applied onto a support to form a film of the radiation curable composition. Curing the film of the radiation curable composition by irradiation with actinic radiation to form a cured film, and heating to heat stretch so that at least a part of the stretched film has a stretching ratio of 100% or more A stretching step.
The cured film of the present invention is formed by the method for forming a cured film of the present invention.

In the present invention, the weight average molecular weight Mw of the polymer formed by polymerization of the radical polymerizable compound in the cured film formed by the method of forming the cured film is 5,000 or more and 50,000 or less, and 7,000 or more. It is preferably 50,000 or less, and more preferably 8,000 or more and 50,000 or less.
In the present invention, the weight average molecular weight Mw is a polystyrene equivalent weight average molecular weight by GPC measurement, and the number average molecular weight Mn is also a polystyrene equivalent number average molecular weight by GPC measurement.
By controlling the weight average molecular weight Mw of the polymer within the above range, the internal stress of the film after heat stretching can be reduced. Thus, according to the present invention, it is possible to suppress deterioration with time of the cured film after stretching. Such control of the weight average molecular weight can be realized by appropriately setting various conditions such as film surface temperature and illuminance in the curing step.

  The ratio Mw / Mn (molecular weight distribution) of the weight average molecular weight Mw to the number average molecular weight Mn of the polymer formed by polymerization of the radical polymerizable compound is preferably 2 or more, and is 2 to 4. Is more preferable, and it is still more preferable that it is 2-3.5. Within the above range, the internal stress of the film after heat stretching can be reduced.

In the said hardening process, it is preferable that the film | membrane surface temperature (exposure temperature) of the film | membrane of the said radiation curable composition is 40 degreeC or more, It is more preferable that it is 40-80 degreeC, It is 40-60 degreeC. Is more preferable. Within the above range, it is easy to control the weight average molecular weight and molecular weight distribution of the polymer produced by polymerization to the preferred ranges.
Moreover, in the said hardening process, it is preferable that the illumination intensity of the said active radiation in the surface of the film | membrane of the said radiation curable composition is 1 W / cm < ² > or more, It is preferable that it is 1-4 W / cm < ² >. More preferably, it is ˜2 W / cm ² . Within the above range, it is easy to control the weight average molecular weight and molecular weight distribution of the polymer produced by polymerization to the preferred ranges.

The heating and stretching step is a step of heating and stretching so that at least a part of the cured film has a stretching ratio of 100% or more, and the maximum stretching ratio is preferably less than 500%, and preferably less than 300%. More preferred. Moreover, it is preferable that it is 30-250 degreeC, and, as for the heating temperature at the time of extending | stretching, it is more preferable that it is 50-200 degreeC.
The heating and stretching step is not particularly limited, but it is preferable to perform stretching while heating the support on which the cured film is formed. For example, various molding processes described later can be used.

(3) Inkjet recording method, inkjet recording apparatus and printed matter The radiation curable composition of the present invention is suitably used as an ink composition for inkjet recording, and the cured film forming method of the present invention is suitable for an inkjet recording method. It can be applied to. Hereinafter, an inkjet recording method, an inkjet recording apparatus, and a printed matter using the radiation curable composition of the present invention as an ink composition will be described.
In the inkjet recording method of the present invention, the ink composition of the present invention is ejected onto a recording medium (support, recording material, etc.) for inkjet recording, and actinic radiation is applied to the ink composition ejected onto the recording medium. It is a method of forming an image by irradiating and curing the ink.

More specifically, the inkjet recording method of the present invention comprises (a ¹ ) a step of ejecting the ink composition of the present invention onto a recording medium, and (b ¹ ) actinic radiation on the ejected ink composition. And a step of curing the ink composition.
By including the steps (a ¹ ) and (b ¹ ), the ink jet recording method of the present invention forms an image with the ink composition cured on the recording medium.
The printed matter of the present invention is a printed matter obtained by using the ink composition of the present invention, and is preferably a printed matter recorded by the inkjet recording method of the present invention.
The ejection is preferably performed using an inkjet head that ejects the ink composition by deformation of the piezoelectric element.
Further, it is preferable that the ejection is performed with a droplet amount of 1 to 10 pl and 1,200 × 1,200 to 4,800 × 4,800 dpi.

In the step (a ¹ ) in the ink jet recording method of the present invention, an ink jet recording apparatus described in detail below can be used.

[Inkjet recording device]
There is no restriction | limiting in particular as an inkjet recording device used for the inkjet recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known inkjet recording apparatus including a commercially available product can eject ink onto a recording medium in the step (a ¹ ) of the inkjet recording method of the present invention.
Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and an actinic radiation source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 1 to 10 pl, preferably 300 × 300 to 4,800 × 4,800 dpi, more preferably 1,200 × 1,200 to It can be driven so that it can be discharged at a resolution of 4,800 × 4,800 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.
In the inkjet recording method of the present invention, it is preferable to use an inkjet head that discharges an ink composition by deformation of a piezoelectric element, a so-called piezo-type inkjet head, as the inkjet head.

  As described above, since the radiation-curable ink composition, like the ink composition of the present invention, desirably discharges the ink composition at a constant temperature, the ink supply tank to the inkjet head portion are insulated. And warming can be performed. The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors in each piping portion and perform heating control according to the flow rate of the ink composition and the environmental temperature. The temperature sensor can be provided near the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of thermal energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

Using the above inkjet recording apparatus, the ink composition of the present invention is ejected by heating the ink composition to preferably 25 to 80 ° C., more preferably 25 to 50 ° C. Preferably it is performed after lowering to 3 to 15 mPa · s, more preferably 3 to 13 mPa · s. In particular, it is preferable to use an ink composition having an ink viscosity at 25 ° C. of 50 mPa · s or less as the ink composition of the present invention, since it can be discharged satisfactorily. By using this method, high ejection stability can be realized.
A radiation curable ink composition such as the ink composition of the present invention generally has a higher viscosity than a water-based ink composition usually used in an ink composition for ink jet recording, and therefore has a large viscosity fluctuation due to temperature fluctuations during ejection. Viscosity fluctuation of the ink composition has a great influence on the change of the droplet size and the change of the droplet discharge speed, and thus causes the image quality deterioration. Therefore, it is necessary to keep the temperature of the ink composition during ejection as constant as possible. Therefore, in the present invention, the temperature control range of the ink composition is preferably set to ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and further preferably set temperature ± 1 ° C. .

Next, (b ¹ ) a step of curing the ink composition by irradiating the discharged ink composition with active radiation will be described.
The ink composition ejected on the recording medium is cured by irradiation with actinic radiation. This is because the polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with actinic radiation to generate radicals and other starting species, and the polymerization reaction of the radical polymerizable compound occurs in the function of the starting species. Because it is promoted. At this time, if a sensitizer is present together with the polymerization initiator in the ink composition, the sensitizer in the system absorbs actinic radiation to be in an excited state, and promotes decomposition of the polymerization initiator by contacting with the polymerization initiator. And a more sensitive curing reaction can be achieved.

  Here, α rays, γ rays, electron beams, X rays, ultraviolet rays, visible light, infrared rays, or the like can be used as the active radiation used. Although the peak wavelength of actinic radiation is based also on the absorption characteristic of a sensitizer, it is preferable that it is 200-600 nm, for example, it is more preferable that it is 300-450 nm, and it is still more preferable that it is 350-420 nm.

Further, the illuminance of the active radiation at the surface of the image of the ink composition discharged onto the recording medium is preferably 1W / cm ² or more, preferably 1~4W / cm ^2, 1~ More preferably, it is ² W / cm ² .

Mercury lamps and gas / solid lasers are mainly used as actinic radiation sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing UV photocurable ink jet recording inks. Yes. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as light sources for photo-curable ink jets.
Further, a light emitting diode (LED) and a laser diode (LD) can be used as the active radiation source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. If even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit actinic radiation centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. The actinic radiation source particularly preferred in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 350 to 420 nm.

The ink composition of the present invention is appropriately irradiated with such actinic radiation for 0.01 to 120 seconds, more preferably for 0.1 to 90 seconds.
Actinic radiation irradiation conditions and a basic irradiation method are disclosed in JP-A-60-132767. Specifically, the light source is provided on both sides of the head unit including the ink composition discharge device, and the head unit and the light source are scanned by a so-called shuttle method. Irradiation with actinic radiation takes a certain period of time (preferably 0.01 to 0.5 seconds, more preferably 0.01 to 0.3 seconds, still more preferably 0.01 to 0.15 seconds) after ink landing. Will be done. In this way, by controlling the time from landing to irradiation of the ink composition to an extremely short time, it is possible to prevent the ink composition that has landed on the recording medium from spreading before curing. In addition, since the ink composition can be exposed to a porous recording medium before the ink composition penetrates to a deep part where the light source does not reach, it is preferable because residual unreacted monomers can be suppressed.
Further, the curing may be completed by another light source that is not driven. International Publication No. 99/54415 pamphlet discloses a method using an optical fiber or a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side of the head unit as an irradiation method. Such a curing method can also be applied to the ink jet recording method of the present invention.

  In the step of irradiating actinic radiation to cure the ink composition, the film surface temperature (exposure temperature) of the film of the ink composition ejected on the recording medium is preferably 40 ° C. or higher, and 40 to 80 More preferably, it is 40 degreeC, and it is still more preferable that it is 40-60 degreeC.

By adopting the ink jet recording method as described above, the dot diameter of the landed ink composition can be kept constant even on various recording media having different surface wettability, and the image quality is improved. In addition, in order to obtain a color image, it is preferable to superimpose in order from the color with the lowest brightness. By superimposing the ink compositions in order of low lightness, it becomes easy for the irradiation rays to reach the lower ink composition, and good curing sensitivity, reduction of residual monomers, and improvement in adhesion can be expected. In addition, irradiation can be performed by discharging all colors and collectively exposing, but exposure for each color is preferable from the viewpoint of promoting curing.
Thus, the ink composition of the present invention can form an image on the surface of a recording medium by being cured with high sensitivity by irradiation with actinic radiation.

  In the present invention, the recording medium is not particularly limited, and a known recording medium can be used as a support or a recording material. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which the above-mentioned metal is laminated or deposited. In addition, as the recording medium in the present invention, a non-absorbable recording medium can be preferably used.

[Heating stretch]
Heat stretching of the recording medium on which an image is formed by the inkjet recording method can be performed by various molding processes. As the forming process for heat stretching, vacuum forming process, pressure forming process, vacuum pressure forming process and embossing process are preferable, vacuum forming process, pressure forming process and vacuum / pressure forming process are more preferable, and vacuum forming process is more preferable. .
As a device for forming and processing the recording medium, a known device can be used, and it may be an apparatus integrated with the ink jet recording apparatus or a separate apparatus.

<Vacuum forming, pressure forming, vacuum pressure forming>
Vacuum forming is a method in which a support on which an image has been formed is preheated to a temperature at which it can be thermally deformed in advance, and is sucked into a mold under reduced pressure and stretched while being pressed and cooled to the mold.
The pressure forming is a method in which a support on which an image is formed is preheated to a temperature at which heat can be deformed in advance, pressurized from the opposite side of the mold, and then compressed and cooled on the mold.
Vacuum / pressure forming is a method in which the pressure reduction and pressurization are performed simultaneously.
For details, see Polymer Dictionary (Maruzen Co., Ltd.) p. Reference can be made to the item “thermoforming” described in 766 to 768 and the literature cited in the item.
The processing temperature is appropriately determined depending on the support type and the support, and the support temperature is preferably 60 to 180 ° C, more preferably 80 to 160 ° C, and more preferably 80 to 150 ° C. More preferably. In the above-mentioned range, there is little change in the color of the image, and it is possible to process with excellent mold releasability.

<Embossing>
Embossing is a process of producing a three-dimensional effect by denting a printed material or the like into an arbitrary shape such as a pattern or a character, and can be processed using, for example, a roller or a press.
An example of embossing is a hot and cold press method, and the method described in JP-A-10-199360 can be referred to.
An example of an embossing apparatus by the hot and cold press method is shown below.
In the embossing apparatus, a lower surface plate (lower surface plate) and an upper surface plate (upper surface plate) are disposed so as to be able to approach and separate from each other. A plate heater is fixed on the lower surface plate, and a plate heater is also fixed on the lower surface of the upper surface plate. Thereby, hot pressing can be performed while heating the support. In this hot press machine, a mold having a convex portion that follows a predetermined emboss shape is attached to the plate-type heater on the lower surface plate, and the convex portion is brought into contact with the heater fixed to the lower surface of the upper surface plate. A mold having a concave portion that matches the shape is attached. Then, an image-formed support is disposed, a cushion sheet is disposed between the support and the concave mold, and the upper surface plate is lowered to support it between the upper surface plate and the lower surface plate. Press the body and cushion sheet. The applied pressure in this hot pressing step is, for example, 30 tons, and the heating temperature by the plate type heater is, for example, 170 ° C. And an upper surface plate is pressed on a lower surface plate, a support body and a cushion sheet are pinched between metal mold | dies, and this hot press is hold | maintained for about 3 minutes. The support is heated by a heater through a mold, and a plurality of convex portions are formed by thermal deformation. Next, the support and the cushion sheet are sandwiched between the molds and placed between the internal water-cooled surface plates without a heater. For example, the internal water-cooled surface plate with a pressure of 30 tons and a holding time of about 3 minutes. Press and cold press. Thereby, the convex shape which carried out the heat deformation by the hot press is hold | maintained, and the molded printed matter which gave the embossing process is obtained. The applied pressure and heating temperature can be appropriately adjusted according to conditions such as the material of the printed matter used and the processed shape.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples.
In the following description, “parts” means “parts by weight” unless otherwise specified.

(Preparation of cyan pigment dispersion 1)
The following pigment, dispersant, and solvent were mixed to obtain a cyan pigment dispersion 1.
・ Face: C.I. I. Pigment Blue 15: 3
(Manufactured by Ciba Specialty Chemicals) 30 parts Dispersant: Polymer dispersant (Solsperse 32000 manufactured by Zeneca) 8 parts Solvent: NK ester AMP-10G
(Phenoxyethyl acrylate, Shin-Nakamura Chemical Co., Ltd.) 62 parts

(Preparation of ink composition)
Cyan pigment dispersion 1, (Component A) radical polymerizable compound (Monomers 1 to 3), (Component B) polymerization initiator, and (Component C) surface segregation polymer were mixed in the formulation shown in Table 1, respectively. Compositions 1-4 were prepared.

In addition to the cyan pigment dispersion 1, each component used for preparing the ink composition shown in Table 1 is as follows.
Monomer 1: V-CAP (N-vinylcaprolactam, manufactured by ISP)
Monomer 2: NK ester AMP-10G (phenoxyethyl acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)
Monomer 3: SR238 (1,6-hexanediol diacrylate, manufactured by Sartomer)
Polymerization initiator: IRGACURE 819 (photopolymerization initiator, manufactured by Ciba Specialty Chemicals)
Surface segregation polymer: Fluorine-containing polymer (14) shown below

  Further, the ratio of the monofunctional monomer in the component A of the ink compositions 1 to 4 is 100% by weight, 98% by weight, 100% by weight, and 93% by weight, respectively.

<Inkjet image recording>
Next, recording on a recording medium was performed using a commercially available inkjet recording apparatus having a piezoelectric inkjet nozzle. The ink supply system was composed of an original tank, supply piping, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head, and heat insulation and heating were performed from the ink supply tank to the inkjet head portion. Temperature sensors were provided near the ink supply tank and the nozzles of the inkjet head, respectively, and temperature control was performed so that the nozzle portions were always 40 ° C. ± 2 ° C. The piezo-type inkjet head was driven so that 1 to 10 pl multi-size dots could be ejected at a resolution of 4,800 × 4,800 dpi. Further, the exposure time was variable, and exposure energy was irradiated. A HAN250NL high-cure mercury lamp (manufactured by GS Yuasa Corporation) was used as the ultraviolet lamp. In the present invention, dpi represents the number of dots per 2.54 cm. As a recording medium, Panlite sheet PC-1151 (manufactured by Teijin Chemicals Ltd.) was used.

<Heat stretching process>
The above print sample was cut into a width of 3 cm and a length of 5 cm, and the length was 10 cm in a 170 ° C environment using a precision universal testing machine (Autograph AGS-1) manufactured by Shimadzu Corporation and a thermostatic chamber TCR2W-200P. It extended so that it might become.

(Examples 1-3 and Comparative Examples 1-3)
In Examples 1 to 3 and Comparative Examples 1 to 3, ink compositions 1 to 4 were filled in the ink jet recording apparatus, and printed materials were obtained under the curing conditions shown in Table 2. Subsequently, the heat-drawing process was performed about the obtained printed matter, and the molded printed matter was obtained. About the obtained molded printed matter, blocking resistance, stretchability, and deformation after stretching were evaluated. Moreover, it measured about the weight average molecular weight Mw and molecular weight distribution (Mw / Mn) of the polymer formed by superposition | polymerization of the radically polymerizable compound in the cured film by an ink composition. These evaluation procedures, evaluation criteria, and measurement methods are as follows.

<Evaluation of blocking resistance>
An unprinted panlite sheet PC-1151 was placed on the image formed after the ultraviolet irradiation, and a weight was applied so that the load was 25 g / cm ² . The evaluation criteria for blocking resistance are as follows.
A: There is no color transfer and there is no sticking feeling.
○: There is no color transfer, but there is a feeling of sticking.
X: There is color transfer.

<Evaluation of stretchability>
The film surface state of the sample after the heat stretching was visually observed. The evaluation criteria for stretchability are as follows.
A: Completely uniform.
○: Color unevenness occurs locally. Δ: Unevenness that can be visually recognized as a whole occurs.
X: Unevenness which can be visually recognized as a whole occurs, and film cracking occurs.

<Evaluation of deformation after stretching>
The sample screen after the above heat-stretching was placed on the top, left standing at room temperature for 30 days, the degree of lifting at the four corners was measured, and the average value was calculated. The evaluation criteria for deformation after stretching are as follows.
A: The average value is less than 1 mm.
○: The average value is 1 mm or more and less than 3 mm.
Δ: The average value is 3 mm or more and less than 10 mm.
X: The said average value is 10 mm or more.

<Measurement of weight average molecular weight and molecular weight distribution>
The cured film is scraped off from the recording medium using a spatula, added to a large excess of tetrahydrafuran (manufactured by Tokyo Chemical Industry Co., Ltd.), and adjusted while adjusting the temperature so that the liquid temperature does not exceed 40 ° C. It was dissolved for 6 hours with a sonic cleaner (UT-105S manufactured by Sharp Corporation). After filtration and concentration, molecular weight measurement was performed. The molecular weight of the polymer represents a weight average molecular weight, and was measured by GPC (GPC HLC-8220 GPC manufactured by Tosoh Corporation). In this GPC measurement, four columns of TSK guardcolumn HHR-H, TSK gelG5000HHR-H, TSK gelG4000HHR-H, and TSK gelG2500HHR-H are used as a column, tetrahydrofuran (THF) is used as an eluent, 40 ° C., 0.5 mL The measurement was performed at a flow rate of / sec. The molecular weight was calculated by comparison with standard polystyrene.

  The evaluation results of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 2 below.

Claims (12)

A radiation-curable composition film containing (Component A) a radically polymerizable compound having an ethylenically unsaturated group and (Component B) a polymerization initiator is cured by irradiation with active radiation;
Heat stretched so that the stretch ratio of at least a part of the film is 100% or more,
A cured film, wherein the polymer formed by polymerization of the radical polymerizable compound in the film has a weight average molecular weight Mw of 5,000 or more and 50,000 or less.   The cured film according to claim 1, wherein a ratio Mw / Mn of a weight average molecular weight Mw to a number average molecular weight Mn of a polymer formed by polymerization of the radical polymerizable compound is 2 or more.   The cured film of Claim 1 or 2 whose film surface temperature of the film | membrane of the said radiation-curable composition at the time of hardening by irradiation of the said active radiation is 40 degreeC or more. The cured film according to any one of claims 1 to 3, wherein an illuminance of the active radiation on the surface of the film of the radiation curable composition at the time of curing by irradiation with the active radiation is 1 W / cm ² or more. .   The cured film of any one of Claims 1-4 whose ratio of the monofunctional polymerizable compound in the said component A is 95 weight% or more.   The said radiation-curable composition further contains a polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group. The cured film as described. A radiation curable composition containing (Component A) a radically polymerizable compound having an ethylenically unsaturated group and (Component B) a polymerization initiator is applied onto a support, and a film of the radiation curable composition is formed on the support. Forming a composition application step;
A curing step of curing the radiation-curable composition film by irradiation with actinic radiation to form a cured film;
A heating and stretching step of heating and stretching so that at least a part of the cured film has a stretching ratio of 100% or more, and
A method for forming a cured film, wherein a weight average molecular weight Mw of a polymer formed by polymerization of the radical polymerizable compound in the cured film is 5,000 or more and 50,000 or less.   The method for forming a cured film according to claim 7, wherein the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the polymer formed by polymerization of the radical polymerizable compound is 2 or more.   The method for forming a cured film according to claim 7 or 8, wherein in the curing step, a film surface temperature of the film of the radiation curable composition is 40 ° C or higher. The method for forming a cured film according to any one of claims 7 to 9, wherein, in the curing step, the illuminance of the active radiation on the surface of the film of the radiation curable composition is 1 W / cm ² or more.   The formation method of the cured film of any one of Claims 7-10 whose ratio of the monofunctional polymerizable compound in the said component A is 95 weight% or more.   The radiation curable composition further contains a polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group. The formation method of the cured film of description.