JP2012153853A - Ink composition, image forming method, and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition which is superior in thermal shrinkage resistance, image flow suitability, elongation ability and punching work suitability of images to be obtained, and to provide an image forming method using the same and a printed matter.SOLUTION: The ink composition comprises: a multifunctional polymerizable compound having an acetal structure (component A); a polymerization initiator (component B); a monofunctional polymerizable compound (component C); and a coloring agent (component D). The ink composition, in which the content of the monofunctional polymerizable compound (component C) in the total content of the polymerizable compounds is 80-99.5 mass%, is used.

Description

  The present invention relates to an ink composition, an image forming method, and a printed matter.

  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. Among these, the ink jet method can be implemented with an inexpensive apparatus, and the ink can be efficiently used because the image is directly formed on the recording medium by ejecting the ink only to the required image portion. Running cost is low.

  The ink jet method can print not only on plain paper but also on non-water-absorbing recording media such as plastic sheets and metal plates. In the ink jet method, the time required for drying and curing of the droplets after printing has an effect on speeding up and high image quality such as productivity of printed matter or sharpness of a printed image.

  As one of the ink jet methods, there is a recording method using an ink for ink jet recording that can be cured by irradiation with active energy rays. According to this method, the productivity of printing is improved and a sharp image can be formed by irradiating the active energy ray immediately after ink ejection or after a certain period of time to cure the ink droplets.

  For example, Patent Document 1 discloses that an active energy ray-curable oxygen inhibition inhibitor having a hemiacetal structure can be applied to the field of ink and the like.

  Patent Document 2 discloses a resin composition for laser engraving having a hemiacetal ester compound, a polymerizable compound, and a polymerization initiator.

JP 2000-144011 A JP 2009-241418 A

However, in each of the above-mentioned techniques, there is no description regarding suppressing the phenomenon that an image of a printed matter formed with an image shrinks by heating, that is, improving “heat-resistant shrinkage”. Further, there is no description about suppressing the phenomenon that a plurality of colors of ink forming an image are mixed when forming a printed material by heating, that is, improving the “image flow aptitude”.
Furthermore, there is no description regarding “stretchability”, which is the ease of stretching by heating the printed material. Further, there is no description regarding suppressing cracking of the image portion (improving “punching suitability”) even under a condition in which a larger stress is applied to the image portion, such as drilling.
An object of the present invention is to provide an ink composition excellent in heat shrinkage resistance, image flowability, stretchability and punching suitability of an image obtained, an image forming method using the same, and a printed matter.

Means for achieving the above object are as follows.
Item 1. (Component A) A polyfunctional polymerizable compound having an acetal structure, (Component B) a polymerization initiator, (Component C) a monofunctional polymerizable compound, and (Component D) a colorant, and a total content of all polymerizable compounds The ink composition wherein the content of the (component C) monofunctional polymerizable compound with respect to the amount is 80% by mass to 99.5% by mass.
Item 2. Item 2. The ink composition according to Item 1, wherein the acetal structure in the (functional component A) polyfunctional polymerizable compound having an acetal structure is a structure represented by the following formula (1).

Formula (1)

In formula (1), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. * Indicates a binding position.

Item 3. Item 2. The ink composition according to Item 1, wherein the acetal structure in the (functional component A) polyfunctional polymerizable compound having an acetal structure is a structure represented by the following formula (2).

Formula (2)

In formula (2), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. * Indicates a binding position.

Item 4. Item 2. The ink composition according to Item 1, wherein the acetal structure in the (functional component A) polyfunctional polymerizable compound having an acetal structure is a structure represented by the following formula (3) or formula (4).

Formula (3)

Formula (4)

In formula (3) and formula (4), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. Z represents at least one group selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group and a —NR— group (R is a hydrogen atom or an alkyl group), or a single bond. X represents a polymerizable group having an ethylenically unsaturated double bond. * Indicates a binding position.

Item 5. Item 5. The ink composition according to any one of Items 1 to 4, wherein the polymerizable group in the polyfunctional polymerizable compound having the (Component A) acetal structure is a (meth) acrylate group or a (meth) acrylamide group. .
Item 6. Item 6. The ink composition according to any one of Items 1 to 5, wherein the (functional component A) polyfunctional polymerizable compound having an acetal structure has a weight average molecular weight of 5,000 to 100,000.
Item 7. The content of the (component A) polyfunctional polymerizable compound having an acetal structure is the sum of the (component A) polyfunctional polymerizable compound having an acetal structure and the polyfunctional polymerizable compound not having an acetal structure. Item 7. The ink composition according to any one of Items 1 to 6, which is 50% by mass to 100% by mass.
Item 8. Item 8. The ink composition according to any one of Items 1 to 7, wherein the (functional component A) polyfunctional polymerizable compound having an acetal structure includes a (meth) acrylate repeating unit or a urethane repeating unit (—NHCOO—). .
Item 9. Item 9. The ink composition according to Item 8, wherein the (functional component A) polyfunctional polymerizable compound having an acetal structure contains a urethane repeating unit (—NHCOO—).
Item 10. A step of forming an image on the recording medium by applying the ink composition according to any one of Items 1 to 9 by an inkjet method, and a step of irradiating the applied ink composition with active energy rays. An image forming method comprising:
Item 11. Printed matter obtained by the image forming method according to Item 10.

  ADVANTAGE OF THE INVENTION According to this invention, the ink composition excellent in the heat-resistant shrinkage | contraction property of the image obtained, image flow aptitude, stretchability, and punching process aptitude, an image forming method using the same, and a printed matter can be provided.

1. Ink Composition The ink composition of the present invention comprises (Component A) a polyfunctional polymerizable compound having an acetal structure, (Component B) a polymerization initiator, (Component C) a monofunctional polymerizable compound, and (Component D) a colorant. And the content of the (functional component C) monofunctional polymerizable compound with respect to the total content of all polymerizable compounds is 80% by mass to 99.5% by mass. Hereinafter, each component may be simply referred to as “(component A)”, “(component B)”, “(component C)”, and “(component D)”.
Hereinafter, the ink composition of the present invention will be described in detail.

((Component A) polyfunctional polymerizable compound having an acetal structure)
The ink composition of the present invention contains (Component A) a polyfunctional polymerizable compound having an acetal structure as an essential component. (Component A) in the present invention is not limited as long as it is a polyfunctional polymerizable compound having an acetal structure. The polyfunctional polymerizable compound in the present invention refers to a compound having two or more polymerizable groups. The acetal structure is preferably a structure represented by the following formula (1).

Formula (1)

In formula (1), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. * Indicates a binding position.

The alkyl group represented by R ^a and R ^b in the formula (1) is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 carbon atom. Particularly preferred. Specific examples of the alkyl group represented by R ^a and R ^b include a methyl group, an ethyl group, a t-butyl group, and the like. These groups may or may not have a substituent, but preferably do not have a substituent.

The thermal cleavage temperature of the acetal structure of (Component A) in the present invention is preferably 90 ° to 200 °, more preferably 90 ° to 180 °. The thermal cleavage temperature can be controlled by appropriately changing the structure of the acetal structure.
The method for measuring the temperature at the time of the thermal cleavage is, for example, that 5 mg of (Component A) is weighed, and 20 ° C./min using a thermal mass measuring device (manufactured by TA Instruments Japan Co., Ltd.). It can obtain | require by the thermal mass measurement when heating from 40 degreeC to 500 degreeC with the temperature increase rate of. That is, it is possible to measure the temperature (T _d10 ) at which the mass is reduced by 10% by continuously heating between 40 ° C. and 500 ° C. as the “thermal cleavage temperature”.

  The acetal structure is more preferably a structure represented by the following formula (2).

Formula (2)

In formula (2), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. * Indicates a binding position.

The alkyl group represented by R ^a and R ^b in the formula (2) is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 carbon atom. Is particularly preferred. Specific examples of the alkyl group represented by R ^a and R ^b include a methyl group, an ethyl group, a t-butyl group, and the like. These groups may or may not have a substituent, but preferably do not have a substituent.

Q in the formula (2) represents —CO—, —SO ₂ —, —C ₆ H ₄ — or —PO ₂ —. As Q represented by the formula (2), —SO ₂ — or —CO— is preferable, and —CO— is particularly preferable.

  The acetal structure is more preferably a structure represented by the following formula (3) or formula (4).

Formula (3)

(Formula 4)

In formula (3) and formula (4), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. Z represents at least one group selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group and a —NR— group (R is a hydrogen atom or an alkyl group), or a single bond. X represents a polymerizable group having an ethylenically unsaturated double bond. * Indicates a binding position.

  When Z in Formula (3) and Formula (4) is an alkylene group, the alkylene group may have a linear structure, a branched structure, or a cyclic structure. The alkylene group preferably has 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Examples of the alkylene group represented by Z include a methylene group and an ethylene group.

  When Z in Formula (3) and Formula (4) is an arylene group, the arylene group preferably has 6 to 18 carbon atoms, more preferably 6 to 14 carbon atoms, and 6 to 6 carbon atoms. 10 is particularly preferred. Examples of the arylene group represented by Z include a phenylene group.

  When Z in Formula (3) and Formula (4) is an alkyleneoxy group (—R—O—, where R is an alkylene group), the alkyleneoxy group is cyclic regardless of whether it is a linear structure or a branched structure. It may be a structure. The alkyleneoxy group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Examples of the alkyleneoxy group represented by Z include an ethyleneoxy group.

  When Z in Formula (3) and Formula (4) is a —COO— group, the —COO— group may be bonded to Q in the direction of —COO— * or —OCO— *. * In the -COO- * and -OCO- * represents a position bonded to Q.

  When Z in Formula (3) and Formula (4) is an —NR— group, the group represented by R in the —NR— group represents a hydrogen atom or an alkyl group. The alkyl group may have a linear structure or a branched structure, or may form a ring, and preferably has 1 to 4 carbon atoms.

  In the formulas (3) and (4), Z may or may not have a substituent, but preferably does not have a substituent.

  Examples of the substituent that Z in formula (3) and formula (4) may have include a carboxyl group, a halogen atom (F, Cl, Br, I, etc.), a hydroxyl group, and the like. (Hereinafter, these substituent groups are referred to as “substituent U”).

  Z in Formula (3) and Formula (4) is at least one selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group, and a —NR— group (R is a hydrogen atom or an alkyl group). Seed groups may be combined. Preferred combinations of groups are a combination of a —COO— group and an alkylene group, a combination of an alkyleneoxy group, a —NR— group, a —COO— group and an arylene group, and a combination of an alkyleneoxy group and an arylene group.

  Z in the formula (3) and the formula (4) is preferably an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group or an —NR— group, more preferably an alkylene group, an arylene group or an alkyleneoxy group.

Q in Formula (3) and Formula (4) represents —CO—, —SO ₂ —, —C ₆ H ₄ — or —PO ₂ —, preferably —CO— or —SO ₂ —, and —CO—. Is particularly preferred.

When R ^a and R ^{b in} Formula (3) and Formula (4) are alkyl groups, the alkyl group may have a linear structure, a branched structure, or a cyclic structure. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms.

  X in Formula (3) and Formula (4) represents a polymerizable group having an ethylenically unsaturated double bond. Examples of the group having an ethylenically unsaturated double bond include (meth) acryloyl group, (meth) acrylate group, (meth) acrylamide group, vinyl ether group, maleimide group, vinylsulfonamide group, and N-vinylsulfonamide. Group, an allyl group, and the like, and a (meth) acrylamide group or a (meth) acrylate group is preferable in terms of imparting appropriate flexibility. “(Meth) acrylamide” means at least one of acrylamide and methacrylamide, and the notation of adding (meth) to other (meth) acryloyl groups, (meth) acrylate groups, and the like is the same as this. .

As a preferable combination of Z, Q, R ^a , R ^b and X in the formula (3) and the formula (4), Z is an alkylene group, an arylene group or an alkyleneoxy group, Q is —CO—, R It is preferable that ^a is a hydrogen atom, R ^b is a methyl group, and X is a (meth) acrylamide group or a (meth) acrylate group.

  Specific examples of the groups represented by the formula (3) and the formula (4) include, for example, the following (3-1) to (3-2) or (4-1) to (4-10). Group to be used.

(3-1)

(3-2)

(4-1)

(4-2)

(4-3)

(4-4)

(4-5)

(4-6)

(4-7)

(4-8)

(4-9)

(4-10)

  The ratio of (Component A) in the ink composition in the invention is preferably, for example, 0.25 to 20% by mass, more preferably 0.3 to 15% by mass, and 0.5 to 10%. It is particularly preferable that the content is% by mass.

  In the ink composition of the present invention, (Component A) a polyfunctional polymerizable compound having an acetal structure and (Component A) a polyfunctional polymerizable compound having an acetal structure with respect to the sum of polyfunctional polymerizable compounds not having an acetal structure described later. The content of the functional polymerizable compound is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and particularly preferably 80% by mass to 100% by mass.

  (Component A) may be a low molecular compound having a molecular weight of 300 or more and less than 2,000, or a polymer compound having a weight average molecular weight of 2,000 or more. From the viewpoint of image flowability after curing the ink composition, (Component A) is preferably a polymer compound having a weight average molecular weight of 5,000 or more, and a weight average molecular weight of 5,000 to 100,000. Is more preferable.

  The weight average molecular weight is measured by gel permeation chromatography (GPC). GPC uses HLC-8020GPC (manufactured by Tosoh Corporation), TSKgel SuperHZM-H, TSKgel SuperHZ4000, TSKgel SuperHZ200 (4.6 mm ID × 15 cm, Tosoh Corporation) as columns and THF (tetrahydrofuran) as an eluent. Is used.

  Hereinafter, the case where (Component A) is a low molecular compound having a molecular weight of 300 or more and less than 2,000 will be described in detail.

  When (Component A) is a low molecular weight compound having a molecular weight of 300 or more and less than 2,000, it is preferably a compound represented by the following general formula (1-L).

(1-L)

In formula (1-L), R ^y represents a residue obtained by removing n hydrogen atoms from a saturated or unsaturated hydrocarbon, and T represents a group represented by the following formula (31) or formula (41). To express. n represents an integer of 2 to 6.

Formula (31)

Formula (41)

In formulas (31) and (41), Z is at least one selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group, and a —NR— group (R is a hydrogen atom or an alkyl group). Or a single bond. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. R ^a and R ^b each independently represents a hydrogen atom or an alkyl group. X represents a polymerizable group having an ethylenically unsaturated double bond. * Indicates a binding position.

The saturated hydrocarbon in the residue obtained by removing n hydrogen atoms from the saturated hydrocarbon represented by R ^y in the formula (1-L) may have a linear structure, a branched structure, or a cyclic structure. It may be. As said saturated hydrocarbon, C1-C20 is preferable and C1-C10 is still more preferable. Specific examples of the saturated hydrocarbon include cyclohexane, ethane, butane and the like.

The unsaturated hydrocarbon in the residue obtained by removing n hydrogen atoms from the unsaturated hydrocarbon represented by R ^y in the formula (1-L) may have a linear structure or a branched structure. A cyclic structure may be sufficient, C2-C18 is preferable, and C6-C14 is still more preferable. Specific examples of the unsaturated hydrocarbon include benzene and naphthalene.

Z, Q, R ^a , R ^b and X in formula (31) and formula (41) at T in formula (1-L) are Z, Q in formula (3) and formula (4) described above. , R ^a , R ^b and X are the same including the definition and preferred range.

  N in the formula (1-L) represents an integer of 2 to 6, preferably 2 to 4, more preferably 2 to 3, and particularly preferably 2.

  When (Component A) is a low molecular compound having a molecular weight of 300 or more and less than 2,000, the following compounds (M-1) to (M-9) can be preferably used in the present invention.

(M-1)

(M-2)

(M-3)

(M-4)

(M-5)

(M-6)

(M-7)

(M-8)

(M-9)

When (Component A) is a low molecular weight compound, (Component A) can be synthesized by reacting an acidic compound such as a carboxylic acid with a vinyl ether compound at room temperature to 100 ° C. in the presence of an appropriate catalyst. Such a synthesis reaction proceeds even in the absence of a catalyst, but it is preferable to use a trace amount of an acid catalyst as necessary. As the acid catalyst used in the synthesis, pyridinium, p-toluenesulfonate, and p-toluenesulfonic acid are preferable in that a good balance between polyaddition and depolymerization is maintained. Moreover, you may perform a synthesis | combination by adding a solvent as needed. For example, when there is a concern about the cleavage of the hemiacetal ester bond due to heat of reaction, it is preferable to dilute with tetrahydrofuran, methyl isobutyl ketone, 2-butanone, or the like.
Specifically, (Component A) is a carboxylic acid group-containing compound synthesized by the method described in JP-A No. 2004-126057 and 1,4-cyclohexanedimethanol divinyl ether (manufactured by Aldrich). It can be synthesized by reacting a commercially available polyfunctional vinyl ether compound or the like under known reaction conditions. For example, “Network polymer” Vol. 22, no. 4, p28-37 (2001), “Macromolecules”, Vol. 32, p9059-9061 (1999), and the like, and synthesizing the two compounds in combination. Can do.

  Hereinafter, the case where (Component A) is a polymer compound having a weight average molecular weight of 5,000 or more will be described in detail.

  When (Component A) is a polymer compound, (Component A) is not limited to the polymer structure as long as it is a polyfunctional polymerizable compound having an acetal structure.

  When (Component A) is a polymer compound, the repeating unit capable of forming a polymer structure is a known or commercially available repeating unit such as styrene, (meth) acrylate, (meth) acrylamide, ester, urethane, urea, etc. Monomers that can be constructed can be used. Specifically, the monomer etc. which are represented with the following compound groups can be mentioned, for example.

―Compound group―
Monomers capable of constituting styrene repeating units such as styrene and p-methoxystyrene,
Methyl (meth) acrylate, ethyl (meth) acrylate, allyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, Stearyl (meth) acrylate, cyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexylglycol (meth) acrylate, butoxyethyl (meth) acrylate, butoxymethyl ( (Meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate Rate, 2,2,2-tetrafluoroethyl (meth) acrylate, 1H, 1H, 2H, 2H-perfluorodecyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4 , 5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, glycidyloxybutyl (meth) acrylate, glycidyl Roxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydride Xylpropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorooctyl Monomers capable of constituting (meth) acrylate repeating units such as ethyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate,
Monomers capable of constituting acrylamide repeating units such as (meth) acrylamide, N-butyl (meth) acrylamide, Np-hydroxyphenyl (meth) acrylamide, p-sulfamoylphenyl (meth) acrylamide,
A combination of diphthalic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, and diol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol. A monomer capable of constituting an ester repeating unit such as a condensation product,
Construct urethane repeating units such as tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, norbornene diisocyanate, dicyclohexylmethane-4,4-diisocyanate, diphenylmethane-4,4-diisocyanate, dimer diisocyanate Diisocyanate component monomer capable of
Polyol component monomers that can constitute urethane or urea repeating units such as alkylene diols, polyether diols, polyester diols, and polycarbonate diols.

  Among these, it is particularly preferable to have a (meth) acrylate repeating unit or a urethane repeating unit (—NHCOO—), and it is particularly preferable to have a urethane repeating unit (—NHCOO—).

When (Component A) is a polymer compound, (Component A) includes (i) an embodiment having an acetal structure in the side chain, (ii) an embodiment having an acetal structure at the main chain end, and (iii) an acetal structure on the side. It can take the form which has a chain | strand and the principal chain terminal. Among these, (Component A) is preferably the above-described (i) or (iii) embodiment having an acetal structure in the side chain.
Hereinafter, three modes that (Component A) can take ((i) an embodiment having an acetal structure in the side chain, (ii) an embodiment having an acetal structure at the end of the main chain, and (iii) an acetal structure having the side chain and the main chain) Each of the preferred structures will be described in detail with respect to the embodiment having both ends.

(I) Aspect Having Acetal Structure in Side Chain Hereinafter, a preferred structure of an aspect in which (Component A) has an acetal structure in the side chain is described.

  When (Component A) has an acetal structure in the side chain, it is preferable that the repeating unit containing an acetal structure has a structure represented by the following formula (7).

Formula (7)

Wherein (7), ^{X a} is a residue obtained by removing three hydrogen atoms from a hydrocarbon having 1 to 10 carbon atoms. W ^a represents a single bond or an alkylene group. T ′ represents a group represented by the following formula (32) or formula (42). * Indicates a binding position.

Formula (32)

Formula (42)

In Formula (32) and Formula (42), Z is at least one selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group, and an —NR— group (R is a hydrogen atom or an alkyl group). Represents a group of species or a single bond. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. R ^a and R ^b each independently represents a hydrogen atom or an alkyl group. X represents a polymerizable group having an ethylenically unsaturated double bond. * Indicates a binding position.

Z, Q, R ^a , R ^b and X in formula (32) and formula (42) are defined as Z, Q, R ^a , R ^b and X in formula (3) and formula (4), respectively. The same applies to the preferred range (including preferred combinations).

X ^a in the formula (7) represents the three a residue obtained by removing a hydrogen atom from a hydrocarbon having 1 to 10 carbon atoms. The hydrocarbon having 1 to 10 carbon atoms may be linear or branched. The hydrocarbon preferably has 2 to 6 carbon atoms, and particularly preferably 3 to 5 carbon atoms. Specific examples include residues obtained by removing three hydrogen atoms from alkanes such as propane, 2-methylpropane, butane, pentane, and cyclohexane.

W ^a in Formula (7) represents ^a single bond or an alkylene group, and a single bond is preferable.

The alkylene group represented by W ^a in the formula (7) may have a linear structure, a branched structure, or a cyclic structure. The alkylene group preferably has 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms. The alkylene group represented by W ^a, for example, methylene group, an ethylene group, and the like.

  Specific examples (7-1) to (7-2) of the repeating unit represented by the formula (7) are shown below, but are not limited thereto.

(7-1)

(7-2)

  When (Component A) has an acetal structure in the side chain, (Component A) more preferably has a repeating unit structure represented by the following formula (5) in the main chain.

Formula (5)

In Formula (5), R ^x represents at least one group selected from the group consisting of an alkylene group and an arylene group. * Indicates a binding position.

The alkylene group represented by R ^X in Formula (5) is preferably an alkylene group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms. It is. The alkylene group may be a linear structure, a branched structure, or a cyclic structure, and is preferably a cyclic structure (cycloalkylene group). Specific examples include a cyclopropylene group and a cyclohexylene group.

The arylene group represented by R ^X in formula (5) is preferably an arylene group having 6 to 15 carbon atoms, and specifically includes a phenylene group, a tolylene group, a naphthalenylene group, a biphenylene group, and the like. .

R ^X in formula (5) may be combined with an alkylene group or an arylene group. As a preferable group combination, a combination of an alkylene group having 1 to 12 carbon atoms and an arylene group having 6 to 15 carbon atoms is preferable.

R ^X in formula (5) may or may not have a substituent, but preferably does not have a substituent.

  Examples of the substituent in the case where these groups have a substituent include the substituent U which Z in Formula (3) may have.

  Specific examples (5-1) to (5-4) of the repeating unit represented by the formula (5) in the (component A) polymer compound are listed below, but the present invention is not limited thereto.

(5-1)

(5-2)

(5-3)

(5-4)

  When (Component A) has an acetal structure in the side chain, (Component A) may further have a repeating unit represented by the following formula (6) in addition to the repeating unit represented by the above formula (5). More preferred.

Formula (6)

  In formula (6), R represents an alkylene group. n represents an integer of 1 to 10.

  The alkylene group represented by the formula (6) may have a linear structure, a cyclic structure, or a branched structure. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms.

When (Component A) has an acetal structure in the side chain, it is particularly preferable to have a structure represented by the following general formula (A ′).

Formula (A ')

In the formula (A ′), R ^x represents at least one group selected from the group consisting of an alkylene group and an arylene group. R represents an alkylene group. n represents an integer of 1 to 10. X ^a is a residue obtained by removing three hydrogen atoms from a hydrocarbon having 1 to 20 carbon atoms. W ^a represents a single bond or an alkylene group. T ′ represents a group represented by the following formula (34) or formula (44). * Indicates a binding position. “a”, “b”, and “c” represent a composition ratio (on a molar basis), and the sum of a, b, and c is 100.

Formula (34)

Formula (44)

In formula (34) and formula (44), Z is at least one selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group and a —NR— group (R is a hydrogen atom or an alkyl group). Represents a group of species or a single bond. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. R ^a and R ^b each independently represents a hydrogen atom or an alkyl group. X represents a polymerizable group having an ethylenically unsaturated double bond. * Indicates a binding position.

^{R x} in formula (A') is preferable ranges are also included, is the same as ^{R x} in formula (5).

  R in the formula (A ′) is the same as R in the formula (6) including a preferable range.

^X a, ^{W a} and T'in formula (A') is preferable ranges are also included, ^X a in the formula (7) are the same as ^{W a} and T'.

  In the formula (A ′), a, b, and c represent the composition ratio in (component A), and the sum of a, b, and c is 100 (the composition ratio is on a molar basis). Preferably 50 ≦ a + b ≦ 99 and 1 ≦ c ≦ 50, more preferably 50 ≦ a + b ≦ 90 and 10 ≦ c ≦ 50.

  As a synthesis method of an embodiment in which (Component A) has an acetal structure in the side chain, for example, a monomer such as a diol having a specific structure can be synthesized by performing a known polycondensation reaction. Specifically, 2,2-dimethyl-1,3-dioxolane-4-methanol (manufactured by Wako Pure Chemical Industries, Ltd.) and the like are used as starting materials. Am. Chem. Soc. A diol having a vinyl ether group can be synthesized by vinyl etherification with reference to 2002, Vol 124, p1590, etc., and deacetalization using a methanol solution or the like. By synthesizing a vinyl ether group-containing polymer compound obtained by polymerizing a vinyl ether group-containing monomer by the above-described method, a coloring material, Vol. 67, No. 12, pages 766-774, published in 1994, coloring material, no. A polymer compound having an acetal structure in the side chain can be obtained by reacting with a carboxylic acid-containing monomer described in Vol. 69, No. 11, pp. 735-742, published in 1996, and the like. In addition, after performing a known polycondensation reaction using a monomer such as a diol having a carboxylic acid in the side chain described in JP-A-2005-250438 [0089] to [0092], a vinyl ether monomer is reacted. Can also be synthesized.

(Ii) Aspect having an acetal structure at the main chain terminal Hereinafter, a preferred structure of an aspect having an acetal structure at the main chain terminal will be described.

  When (Component A) has an acetal structure at the end of the main chain, it may be contained in at least one of the main chain structures in the polymer structure of the main chain, but may be contained at both ends, It is preferably contained at both ends of the main chain structure. Further, the terminal structure may be branched to have a plurality of acetal structures. When (Component A) has an acetal structure at the main chain terminal, it is preferable to have a structure represented by the following formula (33) or formula (43) at the main chain terminal.

Formula (33)

Formula (43)

In formulas (33) and (43), Z is at least one selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group, and a —NR— group (R is a hydrogen atom or an alkyl group). Or a single bond. Q is _{-CO -, - SO 2 -,} - C 6 H 4 - or -PO ₂ - represents a. R ^a and R ^b each independently represents a hydrogen atom or an alkyl group. X represents a polymerizable group having an ethylenically unsaturated double bond. * Indicates a binding position.

Z, Q, R ^a , R ^b and X in the formulas (33) and (43) are the same as the definitions of Z, Q, R ^a , R ^b and X in the formulas (3) and (4). The same applies to the preferable range.

  When (Component A) has an acetal structure at the end of the main chain, (Component A) preferably has a structure represented by the following formula (51).

Formula (51)

In Formula (51), R ^x represents at least one group selected from the group consisting of an alkylene group and an arylene group. * Indicates a binding position.

^{R x} in the formula (51) is the same as the preferred ranges are also included ^{R x} in the aforementioned formula (5).

  When (Component A) has the structure represented by the formula (51), the proportion of the structural unit (monomer) having the structure represented by the formula (51) is, for example, 10 in all the structural units (monomer). -90 mass% is preferable, More preferably, it is 20-50 mass%.

  When (Component A) has an acetal structure at the main chain end, (Component A) more preferably has a structure represented by the following formula (61) in addition to the above formula (51).

Formula (61)

  In formula (61), R represents an alkylene group. n represents an integer of 1 to 10. * Indicates a binding position.

  R in Formula (61) is the same as R in Formula (6) described above including a preferable range.

  When (Component A) has the structure represented by the formula (61), the proportion of the structural unit (monomer) having the structure represented by the formula (61) is, for example, 20 in all structural units (monomer). -100 mass% is preferable, More preferably, it is 35-100 mass%, Most preferably, it is 40-100 mass%.

  As a synthesis method in which (Component A) has an acetal structure at the end of the main chain, a polymer compound synthesized by a known polycondensation or polyaddition reaction such as polyurethane and polyester is used as a vinyl ether compound having an active hydrogen group. A precursor is synthesized by performing a termination reaction with a carboxylic acid group-containing polymerizable compound described in a coloring material, Vol. 69, No. 11, pages 735-742, 1996, etc. It can synthesize | combine by the method of reacting.

(Iii) Aspect having an acetal structure at the side chain and main chain terminal Hereinafter, a preferred structure of an aspect having an acetal structure at the side chain and main chain terminal will be described.
When (Component A) has an acetal structure at the side chain and main chain terminal, in addition to the structure that the main chain structure preferably has in the embodiment (i) having the acetal structure at the side chain, (ii) the main acetal structure It is preferable that the main chain terminal has a group that the main chain terminal preferably has in the aspect of the chain terminal. More specifically, it is preferable that the main chain structure has the structure of the formula (A ′) and the main chain terminal structure has a group of the formula (33) or the formula (43).

  As the synthesis method of the embodiment in which (Component A) has an acetal structure at the side chain and the main chain end, the synthesis method of the embodiment having the acetal structure at the side chain and the synthesis method of the embodiment having the acetal structure at the main chain end are combined. Can be synthesized.

  Specific examples in the case where (Component A) in the present invention is a polymer compound are given below. The (component A) polymer compound of the present invention is not limited to the following specific examples.

((Component B) polymerization initiator)
The ink composition of the present invention contains a polymerization initiator.
The polymerization initiator of the present invention may be either a thermal polymerization initiator or a photopolymerization initiator, but in the present invention, a photopolymerization initiator is preferably mentioned. As the photopolymerization initiator, a known photopolymerization initiator can be appropriately selected and used according to the kind of the polymerizable compound and the purpose of use of the ink composition.
The photopolymerization initiator used in the ink composition of the present invention is a compound that absorbs external energy (light) and generates radicals that are polymerization initiation species. In the photopolymerization initiator, the light for initiating polymerization indicates active irradiation rays, that is, γ rays, β rays, electron beams, ultraviolet rays, visible rays, infrared rays, and the like, and preferably ultraviolet rays.

  As the photopolymerization initiator, known compounds can be used. Preferred photopolymerization initiators that can be used in the present invention include (a) aromatic ketones, (b) acylphosphine oxide compounds, and (c) aromatics. Onium salt compound, (d) organic peroxide, (e) thio compound, (f) hexaarylbiimidazole compound, (g) ketoxime ester compound, (h) borate compound, (i) azinium compound, (j) Examples thereof include metallocene compounds, (k) active ester compounds, (l) compounds having a carbon halogen bond, and (m) alkylamine compounds.

  These photopolymerization initiators may use the above compounds (a) to (m) alone or in combination. The photopolymerization initiator in the present invention is preferably used alone or in combination of two or more.

  Preferable examples of (a) aromatic ketones, (b) acylphosphine oxide compounds, and (e) thio compounds include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY”, J. MoI. P. FOUASSIER, J.A. F. RABEK (1993), pp. Examples include compounds having a benzophenone skeleton or a thioxanthone skeleton described in 77-117. More preferable examples include α-thiobenzophenone compounds described in JP-B-47-6416, benzoin ether compounds described in JP-B-47-3981, α-substituted benzoin compounds described in JP-B-47-22326, Benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, dialkoxybenzophenones described in JP-B-60-26483, JP-B-60-26403, JP-A Benzoin ethers described in JP-A-62-81345, JP-B-1-34242, US Pat. No. 4,318,791, α-aminobenzophenones described in European Patent 0284561A1, JP-A-2-21152 P-Di (dimethylaminobenzoyl) benze Thio-substituted aromatic ketones described in JP-A-61-194062, acylphosphine sulfides described in JP-B-2-9597, acylphosphines described in JP-B-2-9596, and JP-B-63-61950 Thioxanthones, and coumarins described in JP-B-59-42864. Moreover, the polymerization initiators described in JP 2008-105379 A and JP 2009-114290 A are also preferable.

  Among these, in the present invention, it is preferable to use an aromatic ketone or an acylphosphine oxide compound as a photopolymerization initiator, and p-phenylbenzophenone (manufactured by Wako Pure Chemical Industries, Ltd.), bis (2, 4, 6 -Trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819: manufactured by BASF Japan), bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphenylphosphine oxide, 2,4,6-trimethylbenzoyl -Diphenyl-phosphine oxide (Darocur TPO: manufactured by BASF Japan, Lucirin TPO: manufactured by BASF Japan) and the like are preferable.

A polymerization initiator can be used individually by 1 type or in combination of 2 or more types.
The content of the polymerization initiator in the ink composition is preferably 2 to 25% by mass, more preferably 5 to 20% by mass, and still more preferably 5 to 15% by mass with respect to the ink composition.

((Component C) monofunctional polymerizable compound)
The ink composition of the present invention contains (Component C) monofunctional polymerizable compound, and the content of (Component C) monofunctional polymerizable compound with respect to the total content of all polymerizable compounds is from 80% by mass to 99.5% by mass. % Is mandatory.

The content of the (component C) monofunctional polymerizable compound in the total polymerizable compound in the ink composition of the present invention is 80 to 99.5% by mass, preferably 85 to 99% by mass, and 90 to 99% by mass. More preferably.
The monofunctional polymerizable compound used in the ink composition of the present invention is not limited as long as it is a polymerizable compound having one polymerizable group.
The monofunctional polymerizable compound used in the ink composition of the present invention may be either a radical polymerizable compound or a cationic polymerizable compound, but in the present invention, a radical polymerizable compound is preferable, Examples thereof include compounds having an ethylenically unsaturated bond capable of radical polymerization. More specifically, any compound having at least one ethylenically unsaturated bond capable of radical polymerization in the molecule may be used.

  Examples of polymerizable monomers having an ethylenically unsaturated bond capable of radical polymerization include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, unsaturated carboxylic acid esters, and the like. A salt having an ethylenically unsaturated group; acrylonitrile; styrene and the like. Further, various macromonomers such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides and unsaturated polyurethanes are also included.

  Examples of such monofunctional compounds are preferably 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, tridecyl acrylate, 2-phenoxyethyl acrylate, N- Methylol acrylamide, diacetone acrylamide, epoxy acrylate, isobornyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl phthalate Acid, methoxy-polyethylene glycol acrylate, 2-acryloyloxyethyl-2-hydro Cyethylphthalic acid, cyclic trimethylolpropane formal acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, ethoxylated phenyl acrylate, 2-acryloyloxyethyl succinic acid, nonylphenol EO adduct acrylate, phenoxy-polyethylene glycol acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, lactone-modified acrylate, stearyl acrylate, isoamyl acrylate, isomyristyl acrylate, isostearyl acrylate, lactone-modified acrylate, etc .; methyl methacrylate , N-butyl methacrylate, allyl methacrylate, glycidyl methacrylate , Benzyl methacrylate, methacrylate compounds such as dimethylaminoethyl methacrylate; allyl compounds such as allyl glycidyl ether.

  Also suitable are monofunctional vinyl ether compounds. Specific examples of the monofunctional vinyl ether compound include, for example, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, n-octadecyl vinyl ether, 2-ethylhexyl vinyl ether, n -Nonyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, Butoxyethylbi Ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol mono Vinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxy polyethylene glycol vinyl ether, cyclohexanedimethanol monovinyl ether, isopropenyl ether-O-pro Ren carbonate, and the like.

  In addition, N-vinyl compounds such as N-vinyl lactams and N-vinylformamide are also preferable. Preferred examples of N-vinyl lactams are represented by the following formula.

  In the above, m represents an integer of 1 to 5, m is preferably an integer of 2 to 4, m is more preferably 2 or 4, and m is 4, that is, N-vinylcaprolactam. It is particularly preferred.

-Cationically polymerizable compound-
Examples of the monofunctional polymerizable compound that can be used in the present invention also include a cationic polymerizable compound. There is no particular limitation as long as it is a compound that causes a polymerization reaction with an acid generated from a photoacid generator and cures, and various known cationically polymerizable compounds known as photocationically polymerizable compounds can be used. Examples of the cationic polymerizable compound include an epoxy compound and an oxetane compound.

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

  In the present invention, the molecular weight of the monofunctional polymerizable compound is preferably 130 to 3000, and more preferably 130 to 500.

(Polyfunctional polymerizable compound having no acetal structure)
The ink composition of the present invention may contain a polyfunctional polymerizable compound having no acetal structure.
Examples of radically polymerizable polyfunctional compounds having no acetal structure include bis (4-acryloxypolyethoxyphenyl) propane, tripropylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, dipentaerythritol tetraacrylate, Trimethylolpropane (PO-modified) triacrylate, oligoester acrylate, hydroxypivalate neopentyl glycol diacrylate, tetramethylol methane triacrylate, dimethylol tricyclodecane diacrylate, modified glycerin triacrylate, bisphenol A diglycidyl ether acrylic acid addition , Modified bisphenol A diacrylate, PO adduct diacrylate of bisphenol A, Sphenol A EO adduct diacrylate, dipentaerythritol hexaacrylate, propylene glycol diglycidyl ether acrylic acid adduct, acrylate compounds such as ditrimethylolpropane tetraacrylate; polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate 2,2-bis And methacrylate compounds such as (4-methacryloxypolyethoxyphenyl) propane. Other examples include allyl compounds such as diallyl phthalate and triallyl trimellitate. PO represents propylene oxide, and EO represents ethylene oxide. More specifically, Shinzo Yamashita, “Crosslinker Handbook”, (1981 Taiseisha); Kato Kiyosumi, “UV / EB Curing Handbook (Materials)” (1985, Polymer Publications); Radtech Study Group, “Application and Market of UV / EB Curing Technology”, p. 79, (1989, CMC); Eiichiro Takiyama, “Polyester Resin Handbook”, (1988, Nikkan Kogyo Shimbun) Commercially available products or radically polymerizable or crosslinkable compounds known in the industry can be used.

  Moreover, the polyfunctional vinyl ether which does not have an acetal structure is also mentioned. Examples of the polyfunctional vinyl ether include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butylene glycol divinyl ether, butanediol divinyl ether, Divinyl ethers such as hexanediol divinyl ether, cyclohexane dimethanol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether; trimethylol ethane trivinyl ether, trimethylol propane trivinyl ether, ditrimethylol propane tetrabi Ether, glycerol trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, Propylene oxide addition ditrimethylolpropane tetravinyl ether, ethylene oxide addition pentaerythritol tetravinyl ether, propylene oxide addition pentaerythritol tetravinyl ether, ethylene oxide addition dipentaerythritol hexavinyl ether, propylene oxide addition dipe Polyfunctional vinyl ethers such as data hexavinyl ether, and the like.

  Examples of the radical polymerizable compound having no acetal structure include, for example, JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, and JP-A-9-134011. No., JP-A-2004-514014, etc., photocurable polymerizable compounds used in the photopolymerizable compositions described in each publication are known, and these are also applied to the ink composition of the present invention. Can do.

  In the present invention, the molecular weight of the polyfunctional polymerizable compound having no acetal structure is preferably 130 to 3000, more preferably 130 to 500, as the molecular weight.

((Component D) Colorant)
The ink composition of the present invention contains a colorant. By adding a colorant to the ink composition, the ink composition can form a visible image (colored image).
The colorant that can be used in the ink composition of the present invention is not particularly limited, and various known colorants (pigments and dyes) can be appropriately selected and used depending on the application. For example, when forming an image excellent in weather resistance, a pigment is preferable. As the dye, both water-soluble dyes and oil-soluble dyes can be used, but oil-soluble dyes are preferred.

-Pigment-
First, a pigment that is preferably used as a colorant in the ink composition of the present invention will be described.
The pigment is not particularly limited, and all commercially available organic pigments and inorganic pigments or pigments dispersed in an insoluble resin or the like as a dispersion medium, or a resin is grafted on the pigment surface. Can be used. Moreover, what dye | stained the resin particle with dye can be used.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include C.I. I. Pigment Yellow 1 (Fast Yellow G, etc.), C.I. I. A monoazo pigment such as C.I. Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine type azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).

  C. As a thing which exhibits red or magenta color, C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as C.I. Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Azo lake pigments such as C.I. Pigment Red 57: 1 (Brilliant Carmine 6B); I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Red 174 (Phloxine B Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G 'lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (Thioindigo Bordeaux, etc.); I. Perinone pigments such as C.I. Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.); I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Quinacridone pigments such as CI Pigment Red 122 (quinacridone magenta, etc.); I. Isoindolinone pigments such as CI Pigment Red 180 (isoindolinone red 2BLT, etc.); I. And alizarin lake pigments such as CI Pigment Red 83 (Mada Lake, etc.).

  As a pigment exhibiting blue or cyan, C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Phthalocyanine pigments such as C.I. Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

  As a pigment exhibiting green, C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).

  As a pigment exhibiting an orange color, C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

  Examples of the black pigment include carbon black, titanium black, and aniline black.

Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Strontium titanate (SrTiO ₃ , so-called titanium strontium white) or the like can be used.

  For dispersion of the pigment, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, or a wet jet mill is used. Can do.

It is also possible to add a dispersant when dispersing the pigment. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular weight copolymer, a modified polyacrylate, an aliphatic polyacrylate. Carboxylic acid, naphthalenesulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester, pigment derivative and the like. It is also preferable to use a commercially available polymer dispersant such as Solsperse series manufactured by Lubrizol.
Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

  In the ink composition, as a dispersion medium for various components such as pigments, a solvent may be added, and the polymerizable compound which is a low molecular weight component without a solvent may be used as a dispersion medium. The ink composition of the invention is suitable as an active energy ray-curable ink, and is preferably solvent-free because it is cured after it is applied to a recording medium.

  The volume average particle size of the pigment particles in the ink composition is preferably 0.02 μm to 0.60 μm, more preferably 0.02 μm to 0.10 μm. Further, the maximum particle size is preferably 3 μm or less, more preferably 1 μm or less, and the selection of the pigment, dispersant, dispersion medium, dispersion conditions, and filtration conditions are set so as to be in such a range. The volume average particle diameter is measured using a laser diffraction / scattering particle size distribution analyzer (LA920, manufactured by Horiba, Ltd.) using tripropylene glycol methyl ether as a measurement solvent.

-Dye-
Next, the dyes preferably used as the colorant in the present invention will be described.
The dye can be appropriately selected from conventionally known compounds (dyes). Specific examples include compounds described in paragraph numbers [0023] to [0089] of JP-A No. 2002-114930 and paragraph numbers [0136] to [0140] of JP-A No. 2008-13646. These can also be applied to the present invention.

  The colorant is preferably added in an amount of 0.05% by mass to 20% by mass with respect to the total mass of the ink composition, and more preferably 0.2% by mass to 10% by mass. When an oil-soluble dye is used as the colorant, the content is particularly preferably 0.2% by mass to 6% by mass with respect to the total mass (including the solvent) of the ink composition.

<Water>
The ink composition of the present invention is preferably a non-aqueous ink composition containing substantially no water. Specifically, it is preferably 3% by mass or less, more preferably 2% by mass or less, and particularly preferably 1% by mass or less with respect to the total amount of the ink composition.

<Other ingredients>
Furthermore, components other than those described above can be added to the ink composition of the present invention. This will be sequentially described below.

(Chain transfer agent)
The ink composition of the present invention may further contain a chain transfer agent.
The chain transfer agent can be used without particular limitation as long as it is a substance that moves the active site of the reaction by a chain transfer reaction in the polymerization reaction.

  Specific examples of the chain transfer agent that can be used in the present invention include, for example, halogen compounds such as carbon tetrachloride and carbon tetrabromide; alcohols such as isopropyl alcohol and isobutyl alcohol; 2-methyl-1-butene, 2,4 -Olefins such as diphenyl-4-methyl-1-pentene; sulfur-containing compounds; and the like, but are not limited thereto.

  The molecular weight of the chain transfer agent is preferably 250 or more, particularly preferably 250 or more and 100,000 or less, more preferably 500 or more and 80,000 or less, and particularly preferably 3,000 or more and 80,000 or less.

Only 1 type may be used for a chain transfer agent and it may use 2 or more types together.
The addition amount of the chain transfer agent to the ink composition of the present invention is preferably 0.1% by mass to 15% by mass, and preferably 0.5% by mass to 10% by mass with respect to the total solid mass of the ink composition. More preferably, it is more preferably 1% by mass to 10% by mass.

(Sensitizing dye)
A sensitizing dye can be added to the ink composition of the present invention in order to promote decomposition of the polymerization initiator by irradiation with active energy rays.

As the sensitizing dye, a compound corresponding to the wavelength of the active energy ray that generates an initiation species in the polymerization initiator used in the ink composition may be used, but it is used for a curing reaction of a general ink composition. Considering this, examples of preferable sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.
Polynuclear aromatics (for example, anthracene, pyrene, perylene, triphenylene), thioxanthones (for example, isopropylthioxanthone), xanthenes (for example, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (for example, thiaxene) Carbocyanine, oxacarbocyanine), merocyanines (eg, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones ( For example, anthraquinone), squalium (for example, squalium), coumarins (for example, 7-diethylamino-4-methylcoumarin), and the like can be mentioned. Xanthones may be mentioned as preferred class.
Further, sensitizing dyes described in JP-A-2008-95086 are also suitable.

(Co-sensitizer)
The ink composition of the present invention can also contain a co-sensitizer.
Examples of co-sensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Science”, Vol. 10, page 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59-138205. No. 60-84305, JP-A 62-18537, JP-A 64-33104, Research Disclosure 33825, and the like. Specific examples include triethanolamine. P-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

  Other examples of co-sensitizers include thiols and sulfides such as thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142772, No. 56-75643, such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercapto. And naphthalene.

  Other examples of the co-sensitizer include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in JP-B-48-42965 (eg, tributyltin acetate), JP-B 55- No. 34414, a hydrogen donor described in JP-A-6-308727 (eg, trithiane), a phosphorus compound described in JP-A-6-250387 (eg diethylphosphite), JP-A-8-65779 Si-H and Ge-H compounds described in the above No.

(UV absorber)
An ultraviolet absorber can be used in the ink composition of the present invention.
Examples of the ultraviolet absorber are described in JP-A-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194843, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in No. 24239, compounds that emit ultraviolet light by absorbing ultraviolet rays typified by stilbene and benzoxazole compounds, so-called fluorescent brighteners, and the like.

(Antioxidant)
An antioxidant can be added to the ink composition of the present invention.
Examples of the antioxidant include European published patents, 223739, 309401, 309402, 310551, 310552, 359416, and 3435443. JP, 54-85535, 62-262417, 63-113536, 63-163351, JP-A-2-262654, JP-A-2-71262, Examples thereof include those described in Kaihei 3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.

(Anti-fading agent)
In the ink composition of the present invention, various organic and metal complex anti-fading agents can be used. Examples of organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, and the like.
In addition, examples of the metal complex anti-fading agent include nickel complexes and zinc complexes. No. 17643, No. VII, I to J, ibid. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .

(Conductive salts)
Conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, and dimethylamine hydrochloride can be added to the ink composition of the present invention for the purpose of controlling ejection properties.

(solvent)
The ink composition of the present invention preferably contains no solvent, but may contain a very small amount of a non-curable organic solvent. The content of the solvent in the ink composition is preferably 1% by mass or less with respect to the total amount of the ink composition.
Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol, and chlorine such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether And ether solvents.

(Polymer compound)
Various oil-soluble polymer compounds can be added to the ink composition of the present invention in order to adjust film physical properties.
Examples of oil-soluble polymer compounds include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenol resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellacs, vinyl resins, acrylics. Resins, rubber resins, waxes, and other natural resins can be used. Two or more of these may be used in combination.
In addition, when the ink composition of the present invention is used as a film, a polymer compound that easily segregates on the surface for the purpose of improving tackiness or the like is also suitable. These polymer compounds contain Si and F atoms described in paragraph numbers [0017] to [0037] of JP-A-2008-248119, paragraph numbers [0015] to [0034] of JP-A-2005-250890, and the like. A polymer, a polymer having a long-chain alkyl group in the side chain, and the like can be used.

(Surfactant)
A surfactant may be added to the ink composition of the present invention.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts.
An organic fluoro compound may be used in place of the surfactant.
The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compound include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). (Columns 8 to 17) and those described in JP-A Nos. 62-135826.

In addition to this, for example, a polymerization inhibitor, a leveling additive, a matting agent, a wax for adjusting film properties, a polyolefin, a PET, etc. Further, a tackifier (tackifier) that does not inhibit the polymerization can be contained.
Examples of the polymerization inhibitor include hydroquinone, methoxybenzoquinone, methoxyphenol, phenothiazine, t-butylcatechol, mercaptobenzimidazole, alkyldithiocarbamates, alkylphenols, alkylbisphenols, salicylates, thiodipropionates, phosphines Phytes, nitroxide aluminum complexes and the like. Specific examples include Gerrad 16, 18, 20, 21, 22, (Rahn).
As the tackifier, specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, 5-6p (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms). An ester with an alcohol having, an ester of (meth) acrylic acid with an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid with an aromatic alcohol having 6 to 14 carbon atoms) And a low molecular weight tackifying resin having a polymerizable unsaturated bond.

(Preferred physical properties of ink composition)
The ink composition of the present invention is suitably used for inkjet applications. For this reason, in consideration of ejection properties, the viscosity is at a temperature during ejection (for example, 40 ° C. to 80 ° C., preferably 25 ° C. to 30 ° C.). 7 mPa · s to 30 mPa · s is preferable. More preferably, it is 7 mPa · s to 20 mPa · s. For example, the viscosity of the ink composition of the present invention at room temperature (25 ° C. to 30 ° C.) is preferably 35 to 500 mPa · s, more preferably 35 mPa · s to 200 mPa · s.

  The ink composition of the present invention is suitably used for ink jet recording. When applied to ink jet recording, the ink composition of the present invention is ejected onto a recording medium by an ink jet recording apparatus, and then the ejected ink composition is irradiated with an energy ray and cured to perform recording.

The present inventors include (Component A) a polyfunctional polymerizable compound having an acetal structure, (Component B) a polymerization initiator, (Component C) a monofunctional polymerizable compound, and (Component D) a colorant, It has been found that the effect of the present invention can be achieved by setting the content of the (functional component C) monofunctional polymerizable compound to 80% by mass to 99.5% by mass with respect to the total content of the polymerizable compound. Although it is not clear about this mechanism, the present inventors infer as follows.
That is, it is speculated that as a result of the formation of a heat-cleavable cross-linked structure via the acetal structure, the internal stress due to curing at the time of heating is alleviated and the heat shrinkage resistance is improved. Furthermore, by setting the content of the (component C) monofunctional polymerizable compound to the total polymerizable compound to be 80% by mass to 99.5% by mass, an appropriate flexibility is imparted to the film and the stretchability is improved. It is considered. As a result, it is presumed that the effect of the present invention is improved because the cross-linking structure is maintained at room temperature and a strong film can be formed, and the internal stress is relaxed by the cleavage of the acetal bond during heating. .
In addition, the said mechanism is inference and this invention is not limited to the said mechanism.

2. Image Forming Method and Printed Product The image forming method of the present invention is a method of applying an ink composition of the present invention on a recording medium by an ink jet method using a known ink jet recording apparatus including a commercially available apparatus. A step of forming, and an image forming method of irradiating the obtained image with active energy rays to cure the ink composition. Furthermore, the image forming method may include a step of obtaining a printed matter having a cured image on the recording medium.

  The recording medium (base material) that can be applied to the image forming method of the present invention is not particularly limited, and various non-absorbent resin materials used for ordinary non-coated paper, coated paper, and other so-called soft packaging or Resin films formed into films can be used, and various plastic films include, for example, PET film, OPS film, OPP film, ONy film, PVC film, PE film, TAC film, vinyl chloride sheet, etc. Can be mentioned. In addition, examples of the plastic that can be used as the recording medium material include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers. Metals and glasses can also be used as a recording medium. Furthermore, examples of the recording material applicable to the present invention include a support for a lithographic printing plate.

Examples of active energy rays applied to the image forming method of the present invention include α rays, γ rays, X rays, ultraviolet rays, visible rays, infrared rays, and electron beams. The peak wavelength of the active energy ray is preferably 200 nm to 600 nm, more preferably 300 nm to 450 nm, and still more preferably 350 nm to 420 nm. The output of the active energy rays, is preferably 2,000 mW / cm ² or less, more ^preferably at ^{10mW / cm 2 ~2,000mW / cm 2} , more preferably, 20 mW / ^cm 2 to 1 a 000mW / cm ^2, particularly ^{preferably 50mW / cm 2 ~800mW / cm 2} .

In particular, in the image forming method of the present invention, the active energy ray irradiation, emission wavelength peak is 350Nm～420nm, and maximum illuminance of the recording medium surface is 10mW ^/ cm ² ~2,000mW ^/ cm 2 The light is preferably emitted from a light emitting diode that generates ultraviolet rays. The ink composition of the present invention can be cured with high sensitivity even with low exposure light such as light emitted from a light emitting diode.

  In the image forming method of the present invention, the active energy rays can be exposed collectively after ejecting all colors, but it is preferable to perform exposure for each color.

  Further, as described above, the ink composition of the present invention is suitably used for image formation of general printed matter, and also suitable for a mode in which an image is formed on a recording medium such as a support and then processed. Can be used.

A printed matter molded body may be processed and molded using the printed matter. The printed product is formed by ejecting the ink composition of the present invention onto a recording medium by an inkjet method to form an image, and irradiating the obtained image with active energy rays to cure the ink composition. And a step of obtaining a print having a cured image on the recording medium, and a step of obtaining the print product by molding the print and obtaining a print product by the method for producing a print product of the present invention. Manufactured.
As the recording medium used for the production of the printed matter molded body, a recording medium made of a moldable resin material is used, and examples thereof include PET, polycarbonate, polystyrene and the like.

  As a processing method for producing the print product, vacuum forming, pressure forming, or vacuum / pressure forming is most preferable. In principle, vacuum forming pre-heats a flat support to a temperature at which it can be thermally deformed, sucks it into the mold by decompression, and cools it by crimping to the mold. Pressure is applied from the opposite side to the mold and cooled by pressure. In vacuum / pressure forming, the pressure reduction and pressurization are performed simultaneously.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof. Unless otherwise specified, “%” and “parts” are based on mass.

<Preparation of pigment dispersion>
The following pigments, dispersant, and solvent were mixed to prepare pigment dispersions (Y1, M1, C1, K1, and W1) for each color.

Yellow pigment dispersion (Y1)
Pigment: C.I. I. Pigment Yellow 12: 10 parts Dispersant: Polymer dispersant (Nippon Lubrizol Corp., Solsperse 32000) ... 5 parts Monofunctional monomer: 2-phenoxyethyl acrylate [Biscoat # 192, manufactured by Osaka Organic Chemical Co., Ltd., Radical polymerizable monomer] 85 parts

Magenta pigment dispersion (M1)
Pigment: C.I. I. Pigment Red 57: 1 ... 15 parts-Dispersant: Polymer dispersant [manufactured by Nippon Lubrizol Co., Ltd., Solsperse 32000] ... 5 parts-Monofunctional monomer: 2-phenoxyethyl acrylate ... 80 parts

Cyan pigment dispersion (C1)
Pigment: C.I. I. Pigment Blue 15: 3 ... 20 parts Dispersant: Polymer dispersant [manufactured by Nippon Lubrizol Co., Ltd., Solsperse 32000] ... 5 partsMonofunctional monomer: 2-phenoxyethyl acrylate ... 75 parts

Black pigment dispersion (K1)
Pigment: C.I. I. Pigment Black 7: 20 parts Dispersant: Polymer dispersant (manufactured by Nippon Lubrizol Corporation, Solsperse 32000) ... 5 parts Monofunctional monomer: 2-phenoxyethyl acrylate ... 75 parts

White pigment dispersion (W1)
Pigment: MICROLITH WHITE RA (BASF Japan) 20 parts Dispersant: Polymer dispersant [manufactured by Nippon Lubrizol Corporation, Solsperse 32000] 5 parts Monofunctional monomer: 2-phenoxyethyl Acrylate ... 75 parts

<(Component A) Synthesis of polyfunctional polymerizable compound having acetal structure>
The low molecular compounds (M-1) to (M-9) shown below as (Component A) were synthesized with reference to the method described in JP-A-2009-241418.

(M-1)

(M-2)

(M-3)

(M-4)

(M-5)

(M-6)

(M-7)

(M-8)

(M-9)

(Synthesis of (P-1))
In a 200 ml three-necked flask, 4.7 g of isophorone diisocyanate, 20 g of polypropylene glycol (number average molecular weight 1000), 20 g of 2-butanone, and 0.02 g of neostan U-600 (bismuth catalyst, manufactured by Nitto Kasei Co., Ltd.) are added. And heated at 70 ° C. for 12 hours. 2 g of 2-hydroxyethyl vinyl ether was added, and the mixture was further reacted for 4 hours to obtain a polyurethane having a vinyl ether group at the terminal. Thereafter, 1.7 g of acrylic acid and 0.04 g of phosphoric acid were added and reacted at 40 ° C. for 24 hours. The solution was poured into a large amount of methanol / water mixture and purified by reprecipitation three times. Then, it dried under reduced pressure at 50 degreeC and obtained (P-1).

(Synthesis of (P-2) to (P-4))
(P-2), (P-3) and (P-4) were synthesized in the same manner as (P-1) except that the reaction time was changed.

(Synthesis of (P-5) to (P-13))
(P-5) to (P-13) could be synthesized by the same method as (P-1) using the corresponding raw materials.

(Synthesis of (P-14))
In a 200 ml three-necked flask containing 38 g of 2-butanone and heated to 70 ° C., 38 g of 2-butanone, 4.56 g of acrylic acid, 14 g of methyl methacrylate, V-601 (dimethyl 2,2′-azobis (2 -Methylpropionate), Wako Pure Chemical Industries, Ltd., polymerization initiator) added with 0.28 g of liquid was added over 2 hours, and heated to 70 ° C. under a nitrogen stream. It reacted for 2 hours after dripping. As an initiator, 0.28 g of V-601 was further added and reacted for 4 hours. After cooling to room temperature, 13.4 g of VEEA (2- (2-vinyloxyethoxy) ethyl acrylate) and 0.03 g of phosphoric acid were added and reacted for 24 hours. After pouring into a large amount of methanol / water mixture and reprecipitation purification three times, it was dried under reduced pressure at 50 ° C. to obtain (P-14).

(Synthesis of (P-15) to (P-16))
(P-15) to (P-16) could be synthesized by the same method as (P-14) using the corresponding raw materials.

<Preparation of ink composition>
Example 1
The following components were mixed to prepare the ink composition of Example 1. In particular, the monofunctional monomer component was prepared so that the total amount of the monofunctional monomer including the monofunctional monomer present in the pigment dispersion was the amount shown in Table 1 (unit is part by mass). Mixed.

・ N-vinylcaprolactam (V-CAP, manufactured by BASF, radical polymerizable compound, (component C) monofunctional polymerizable compound) ... 25.9 parts ・ IBOA (isobornyl acrylate, (component C) monofunctional polymerizable Compound) ... 20.0 parts FA-513 (dicyclopentanyl acrylate, (Component C) monofunctional polymerizable compound) ... 15.0 parts ACMO (acryloylmorpholine, (Component C) monofunctional polymerizable compound) ... 5.0 parts · M-1 ((Component A) polyfunctional polymerizable compound having an acetal structure) ... 5.0 parts · Lucirin TPO (manufactured by BASF, (Component B) polymerization initiator) ... 6.0 parts · p-Phenylbenzophenone (manufactured by Wako Pure Chemical Industries, Ltd., (Component B) polymerization initiator) ... 4.0 parts, pigment dispersion (K1) ((Component D) colorant) ... 8.9 parts

-Examples 2-33, Comparative Example 1-
(Component A) Polyfunctional polymerizable compound having an acetal structure, (Component C) monofunctional polymerizable compound, and (Component D) pigment dispersion as a colorant and the amount added were changed as shown in Table 1. Except for the above, Examples 2 to 33 and Comparative Example 1 were prepared in the same manner as Example 1.

Abbreviations in Table 1 indicate the following.
NVC: N-vinylcaprolactam IBOA: isobornyl acrylate FA-513: dicyclopentanyl acrylate ACMO: acryloylmorpholine PEA: 2-phenoxyethyl acrylate NPGPODA: polyfunctional monomer, manufactured by Sartomer, the following structure

[Evaluation]
<Inkjet image recording>
First, the prepared ink composition was filtered with a filter having an absolute filtration accuracy of 2 μm.
Next, recording on a recording medium (soft vinyl chloride sheet) was performed using a commercially available inkjet recording apparatus having a piezoelectric inkjet nozzle. The ink supply system was composed of an original tank, a supply pipe, 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 are provided near the ink supply tank and the nozzle of the inkjet head, respectively, and the temperature is controlled by controlling the heating device according to the temperature measured by the temperature sensor so that the nozzle part is always 70 ° C ± 2 ° C. It was. The piezo-type ink jet head was driven so that multi-size dots of 8 pl to 30 pl could be emitted at a resolution of 720 × 720 dpi (dot per inch), and a solid image was produced. In the present invention, dpi represents the number of dots per 2.54 cm.

After landing, the image was cured by ultraviolet irradiation (exposure) using a proximity type exposure machine (manufactured by Hitachi High-Tech Electronics Engineering Co., Ltd.) having a high-pressure mercury lamp to obtain a printed matter. Specifically, the exposure system, the main scanning speed, and the emission frequency were adjusted so that irradiation was started 0.1 seconds after the ultraviolet rays were condensed to an exposure surface illuminance of 100 mW / cm ² and landed on the recording medium. Further, the exposure time was variable, and exposure energy was irradiated.

Depending on the setting of the distance and the transport speed for the recording medium, the exposure energy was adjusted from ^{0.01J / cm 2 ~15J / cm 2} , was exposed to a sticky feel of an image plane is eliminated.

  Under the following conditions, the heat shrinkage resistance, punching suitability and high temperature elastic modulus of the ink composition were evaluated. The results are shown in Table 1. In addition, the measurement / evaluation method of each evaluation item in Table 1 is as follows.

(Extension evaluation)
In the production of the prints of Examples 1 to 33 and Comparative Example 1, the recording medium (soft vinyl chloride sheet) was replaced with Fasson PE (Fason's polyethylene film: film thickness 100 μm), and ultraviolet rays from a high-pressure mercury lamp after inkjet image recording were performed. A printed material for evaluation of the stretch ratio was obtained in the same manner except that the irradiation was changed to an integrated exposure of 12,000 mJ / cm ² and an illuminance of 2,140 mW / cm ² and the ultraviolet irradiation was performed.
The obtained printed material for evaluation of stretchability is cut into an axial length of 5 cm and a width of 2.5 cm, and stretched at a speed of 30 cm / min using a tensile tester (manufactured by Shimadzu Corporation), whereby the cured film breaks. The rate was measured. The state of extending from the initial length to twice the length was defined as 100% elongation and measured. Table 1 shows specific numerical values of the stretching ratio. The practical allowable range of stretchability is 200% or more, and 300% or more is a result of excellent stretchability.

(Punching process aptitude evaluation)
Using an image produced by inkjet image recording, a sample was punched by hitting a hammer (1.5 kg) to a punch (φ = 10 mm) (punch, manufactured by TRUSCO) and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: Almost no cracking occurred in the periphery of the hole even when confirmed by an optical microscope.
B: Fine cracks that could not be visually confirmed around the hole occurred.
C: A crack that can be visually confirmed was generated around the hole.

(High temperature elastic modulus evaluation)
By the inkjet image recording method, an image (cured film of the ink composition) was formed so as to have a film thickness of 100 μm. The cured film of the obtained ink composition having a thickness of 100 μm was measured for storage elastic modulus E ′ at 90 ° C. using a viscoelasticity measuring device (DVA-225, manufactured by IT Measurement Control Co., Ltd.), and evaluated as follows. Evaluation was made according to the criteria.
-Evaluation criteria-
A: Elastic modulus at 90 ° C. exceeds 2 MPa.
B: Elastic modulus at 90 ° C. is more than 1 MPa and 2 MPa or less.
C: Elastic modulus at 90 ° C. is 1 MPa or less.

(Evaluation of heat shrinkage resistance)
The image produced by the inkjet image recording was stretched by heating so that the stretch ratio was 100%. The heat-stretched sample was punched with a diameter of 50 mm, left in a thermostatic bath at 90 ° C. and 85% RH for 2 weeks, and visually observed for shrinkage and peeling around the punched hole and evaluated with a 50 × optical microscope as follows. Evaluation was made according to the criteria.
-Evaluation criteria-
A: No change.
B: There is a minute peeling that can be seen with a microscope.
C: There is peeling which can be confirmed visually.

(Image flow aptitude evaluation)
<Method for producing resin molded product>
Using a polycarbonate film (trade name Panlite, manufactured by Teijin Kasei Co., Ltd.) having a thickness of 100 μm instead of a soft vinyl chloride sheet as a base material, a 1 mm side grid pattern is printed and a printed layer having a thickness of about 20 μm is formed. Formed.
A vinyl chloride resin (Daiichi Seika Co., Ltd. VM-PEARL) was further applied to the stamp screen, and an adhesive layer having a thickness of 3 μm was provided to obtain a decorative sheet.
An injection molding machine (IS80FPA3, manufactured by Toshiba Machine Co., Ltd.) was used for resin molding. An ABS resin heated to 250 degrees was injected into a mold into which the decorative sheet was inserted, and the mold was allowed to cool and then released to obtain a resin molded product.
Then, the resin molded product was obtained by peeling off from a manufacturing apparatus. In addition, regarding the manufacturing method of a resin molded product, it manufactured with reference to Unexamined-Japanese-Patent No. 2005-262452.
After cooling, visually check for changes in the grid pattern from the back side, and when performing molding by heating, the image evaluation, which is a phenomenon in which the ink of the image forming the printed matter is mixed, is visually or optical microscope based on the following evaluation criteria Was evaluated.
-Evaluation criteria-
A: There was no image flow.
B: Image drift could not be confirmed by visual observation, but it could be confirmed by magnifying the image 100 times with an optical microscope.
C: The image flow was confirmed visually.
A and B are practically acceptable ranges.

  From the above results, it was shown that the Examples had a high stretch ratio, and it was possible to produce a printed material excellent in punching workability, heat shrinkage resistance and image flowability.

Claims (11)

(Component A) polyfunctional polymerizable compound having an acetal structure,
(Component B) polymerization initiator,
(Component C) monofunctional polymerizable compound, and
(Component D) contains a colorant,
The ink composition wherein the content of the (component C) monofunctional polymerizable compound with respect to the total content of all polymerizable compounds is 80% by mass to 99.5% by mass. The ink composition according to claim 1, wherein the acetal structure in the (functional component A) polyfunctional polymerizable compound having an acetal structure is a structure represented by the following formula (1).

Formula (1)
(In formula (1), R ^a and R ^b each independently represents a hydrogen atom or an alkyl group. * Represents a bonding position.) The ink composition according to claim 1, wherein the acetal structure in the (functional component A) polyfunctional polymerizable compound having an acetal structure is a structure represented by the following formula (2).

Formula (2)
(In Formula (2), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. Q represents —CO—, —SO ₂ —, —C ₆ H ₄ — or —PO ₂ —. (* Indicates the binding position.) The ink composition according to claim 1, wherein the acetal structure in the (functional component A) polyfunctional polymerizable compound having an acetal structure is a structure represented by the following formula (3) or formula (4).

Formula (3)

Formula (4)
(In Formula (3) and Formula (4), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group. Q represents —CO—, —SO ₂ —, —C ₆ H ₄ —, or — Represents PO ₂ —, Z represents at least one group selected from the group consisting of an alkylene group, an arylene group, an alkyleneoxy group, a —COO— group and a —NR— group (where R is a hydrogen atom or an alkyl group), or Represents a single bond, X represents a polymerizable group having an ethylenically unsaturated double bond, and * represents a bonding position.)   The ink according to any one of claims 1 to 4, wherein the polymerizable group in the polyfunctional polymerizable compound having the (component A) acetal structure is a (meth) acrylate group or a (meth) acrylamide group. Composition.   The ink composition according to claim 1, wherein the (functional component A) polyfunctional polymerizable compound having an acetal structure has a weight average molecular weight of 5,000 to 100,000.   The content of the (component A) polyfunctional polymerizable compound having an acetal structure is the sum of the (component A) polyfunctional polymerizable compound having an acetal structure and the polyfunctional polymerizable compound not having an acetal structure. The ink composition according to claim 1, wherein the ink composition is 50% by mass to 100% by mass.   The ink according to claim 1, wherein the (functional component A) polyfunctional polymerizable compound having an acetal structure includes a (meth) acrylate repeating unit or a urethane repeating unit (—NHCOO—). Composition.   The ink composition according to claim 8, wherein the (functional component A) polyfunctional polymerizable compound having an acetal structure includes a urethane repeating unit (—NHCOO—). A step of forming an image on the recording medium by applying the ink composition according to any one of claims 1 to 9 by an inkjet method;
Irradiating the applied ink composition with active energy rays.   A printed matter obtained by the image forming method according to claim 10.