JP2016210975A - Active energy ray-curable ink, printed matter and container for food package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active energy ray-curable ink good in curing even under low energy irradiation conditions, also having low migration properties and having reduced odor.SOLUTION: Provided is an active energy ray-curable ink characterized in that, provided that an active energy ray-curable ink is applied to the surface of the ink receiving face 3 of a base material 1 provided with an ink receiving layer at 1.6×10g/cm, ultraviolet irradiation is performed under the conditions where laminated light quality reaches 10 mJ/cmso as to be a cured film 2, the cured film face 3 of the base material p1 free from odor from the cured film face 3 and provided with the cured film 2 cut to the area of 600 cmand the resin layer face of the base material p2 not provided with the cured film are superimposed, it is placed in a 95% ethanol aqueous solution of 1,000 ml under a load of 0.5 kg/cmunder the environment of 25°C and 50%RH for 48 hr. After that, when the base material p2 is immersed in an ethanol aqueous solution at 25°C in a 50% RH environment for 24 hr, and thereafter, when the whole concentration of a photopolymerization initiator present in the ethanol is measured, it is below 100 ppb.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an active energy ray-curable ink.

  Conventionally, printed materials for forms, printed materials for various books, printed materials for packaging such as carton paper, various printed materials for plastics, seals, printed materials for labels, printed materials for arts, printed materials for arts (printed products for art, printed beverages, canned foods, etc.) In order to obtain various printed materials, various printing methods such as lithographic (ordinary lithographic using fountain solution and waterless lithographic plate not using fountain solution), letterpress, intaglio, and stencil printing are adopted. Ink is suitable for each printing method. An active energy ray curable ink is known as one of such inks.

  Active energy ray-curable inks are instantly cured by irradiation with active energy rays to form a strong film, and because of their high curability, post-processing is easy, contributing to productivity improvement and friction resistance. Because it can provide performance, it is used for packaging containers.

  In particular, it is often used in beverage packs for food packaging, but in recent years, the migration (migration) of photopolymerization initiators contained in ink to encapsulated foods has been regarded as a problem. In addition, from the viewpoint of environmental protection, ultraviolet curable inks that can be cured well under irradiation conditions with lower energy have attracted attention.

  Low-energy irradiation conditions refer to conditions lower than ultraviolet irradiation energy from conventional light sources such as mercury lamps, xenon lamps, and methane halide lamps. LED-UV (ultraviolet light-emitting diode) light sources and low-power-consumption ultraviolet rays that have attracted attention in recent years Indicates that a fluorescent lamp or the like is used.

  Patent Document 1 discloses an active energy ray-curable ink composition containing one or more specific photopolymerization initiators (A) and two or more photopolymerization initiators (B). Although it has a curability equivalent to that of the conventional product with an integrated light amount lower than the UV integrated light amount, it is cured on a PET film, and there is no description or suggestion about migration.

  Patent Document 2 discloses an active energy ray containing an α-aminoalkylphenone photopolymerization initiator (A), an α-hydroxyketone photopolymerization initiator (B), a tetrafunctional or higher polymerizable acrylate monomer, and a polymerized oligomer. Although a curable offset ink composition has been disclosed, the conditions used for evaluating the migration of the printed material are much larger than the amount of UV light integrated by the existing UV energy, and there is no description or suggestion under the curing conditions of low UV irradiation energy. .

  Patent Document 3 discloses an active energy ray-curable offset ink composition containing an α-hydroxyketone photopolymerization initiator, an aromatic tertiary amine compound, an extender pigment, a tetra- or higher functional polymerizable acrylate monomer, and a polymerized oligomer. Although disclosed, the conditions used for evaluating the migration of the printed material are much larger than the existing UV integrated light quantity based on the existing UV energy, and there is no description or suggestion on the curing condition of the low UV irradiation energy.

JP 2012-36245 A WO2014 / 129461 Japanese Patent No. 5634652

  An object of the present invention is to provide an active energy ray-curable ink that has good curing even under low energy irradiation conditions, has low migration properties, and has little odor.

  The present inventors have found that the above object can be achieved by containing a specific photopolymerization initiator at a specific content, and have completed the present invention.

That is, the present invention
(1) An active energy ray-curable ink containing the following photopolymerization initiator (A) containing 6 to 25% by mass in an active energy ray-curable ink and a diallyl phthalate resin (B),
The active energy ray curable ink is 1.6 × on the surface of the ink receiving layer of the substrate (P) provided with a resin layer on one side of the base paper (X) and an ink receiving layer on the other side. Applying at 10 ⁻⁴ g / cm ² , and using a UV irradiation device, the UV irradiation is carried out under the condition that the UV irradiation integrated light quantity becomes 10 mJ / cm ² , and the cured film (Q) is cured. There is no odor from the film surface, and the cured film surface of the substrate (p1) provided with the cured film cut to an area of 600 cm ² and the substrate (p2) not provided with the cured film having the same area The resin layer surface was overlaid and allowed to stand for 48 hours in an environment of 25 ° C. and 50% RH at a load of 0.5 kg / cm ² , and then the substrate (p2) was placed in 1000 ml of 95% ethanol aqueous solution. After immersion for 24 hours in an environment of 50 ° C and 50% RH, in ethanol When the total concentration of existing photopolymerization initiator was determined, active energy ray-curable ink and less than 100 ppb,
Base paper (X): Milk carton paper, cardboard paper, coated cardboard paper, Manila cardboard paper, Kent paper, aluminum evaporated paper, synthetic paper (YUPO paper) with a thickness of 2 mm or less
Photopolymerization initiator (A): 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2-[(4-methylphenyl) methyl ] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 4 , 4′-bis (diethylamino) benzophenone or more (2) The photopolymerization initiator (A) is 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1- Butanone or 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone One or more (a1), and 4,4′-bis (diethylamino) benzophenone (a2),
The active energy ray-curable ink according to (1), wherein (a1) :( a2) is from 1: 0.2 to 3 by weight,
(3) The diallyl phthalate resin (B) is an orthotype (b1) and an isotype (b2),
The active energy ray-curable ink according to (1) or (2), wherein (b1) :( b2) is 5:95 to 95: 5 by weight,
(4) Printed matter obtained by using the active energy ray-curable ink according to any one of (1) to (3),
(5) A food packaging container formed using the printed matter according to (4),
It is.

  ADVANTAGE OF THE INVENTION According to this invention, in an active energy ray curable ink, the active energy ray curable ink which has favorable curing | hardening also on low energy irradiation conditions, has low migration property, and there are few odors can be provided.

An example in which a cured film is formed on the surface of an ink receiving layer of a substrate using the active energy ray-curable ink of the present invention, and a load is applied by overlapping the resin layer surface of another substrate on the cured film surface. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. The present embodiment is merely one form for carrying out the present invention, and the present invention is not limited by the present embodiment, and various modifications and embodiments are possible without departing from the gist of the present invention. Is possible.

The active energy ray-curable ink of the present invention (hereinafter also simply referred to as “ink”) comprises a photopolymerization initiator (A) containing 6 to 25 mass% in the ink, and a diallyl phthalate resin (B). Containing the ink on the ink-receiving layer surface of the base material (P) (see FIG. 1 (a)) on which one side of the base paper (X) has a resin layer and the other side having an ink-receiving layer 1.6 × 10 ⁻⁴ g / cm ² , and using a UV irradiation device, UV irradiation is performed under the condition that the UV irradiation integrated light quantity becomes 10 mJ / cm ² , and the cured film (Q) (FIG. 1 (b)), the cured film surface of the base material (p1) provided with the cured film having no odor from the cured film surface and cut into an area of 600 cm ² , and the same area The resin layer surface of the base material (p2) not provided with the cured film is overlapped (see FIG. 1 (c)). And after standing for 48 hours in an environment of 25 ° C. and 50% RH at a load of 0.5 kg / cm ² (see FIG. 1 (d)), the substrate (p2) was mixed with 1000 ml of 95% aqueous ethanol solution. It is characterized by being less than 100 ppb when the total concentration of the photopolymerization initiator present in ethanol is measured after immersion for 24 hours in an environment of 25 ° C. and 50% RH.

  When the photopolymerization initiator (A) is less than 6% by mass, the curability is inferior. More preferably, it is 10-15 mass% in ink. An ink having good printability can be obtained, and a printed matter with less odor can be obtained when printing with a multicolor set.

  The photopolymerization initiator (A) is 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2-[(4-methylphenyl). ) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide , 4,4′-bis (diethylamino) benzophenone is preferable. These are preferred because there is no odor from the cured film surface when cured.

Of these, particularly preferred are 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone or 2- (dimethylamino) -2-[(4-methylphenyl) methyl. ] 1- [4- (4-morpholinyl) phenyl] -1-butanone selected from (a1) and 4,4′-bis (diethylamino) benzophenone (a2), wherein (a1) and (A2) is preferably contained in the active energy ray-curable ink in an amount of 6 to 25% by mass. If it is less than 6% by mass, the curability is inferior, and if it exceeds 25% by mass, the solid content of the pigment decreases and the concentration decreases. More preferably, it is 10-15 mass% in ink.
Furthermore, it is preferable that (a1) :( a2) is 1: 0.2 to 3 by weight. When (b2) is less than 0.2, the surface curability is inferior, and when it exceeds 3, the internal curability is inferior. More preferably, (a1) :( a2) is 1: 0.5-2. By being in the said range, sufficient sclerosis | hardenability is acquired and transferability (low migration) is excellent.

The type of paper used for the base paper (X) is not particularly limited, but paperboard is mainly used. In particular, it is preferably at least one selected from milk carton paper, cardboard paper, coated cardboard, Manila cardboard, Kent paper, aluminum vapor-deposited paper, and synthetic paper (Yupo paper) having a thickness of 2 mm or less. The basis weight of base paper is preferably from 100 to 1500 g / ^{m 2,} more preferably from 200 to 1000 g / ^{m 2.} If the basis weight is too small, the strength of the container becomes weak, and if the basis weight is too large, the paper becomes too thick and molding tends to be difficult.

  The base paper (X) is preferably a base material (P) having a resin layer on one side and an ink receiving layer on the other side.

  The resin layer is selected from resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate and the like, and the layer is formed on one side and / or both sides of the base paper (X). Is formed. Further, a multilayer structure composed of low density polyethylene / medium density polyethylene / low density polyethylene or low density polyethylene / high density polyethylene / low density polyethylene may be used. The resin layer may be formed by bonding the resin film to the base paper with an adhesive or the like, or by extruding and laminating the resin on the base paper. The thickness of the resin layer is preferably in the range of 20 to 100 μm. If the thickness of the resin layer is too thin, it is difficult to maintain the shape, and there is no difference in the effect obtained even if the thickness exceeds 100 μm.

  The ink receiving layer is preferably provided on the other surface on which the resin layer is provided. In the case where the resin layer is provided on both surfaces, either one of the surfaces is used as an ink receiving layer by corona treatment or the like.

  The unit of the photopolymerization initiator concentration (hereinafter, also simply referred to as “elution concentration”) is ppb, and is quantified by a liquid chromatograph mass spectrometer or the like. At that time, a calibration curve using an ethanol solution for the photopolymerization initiator. Is calculated in advance by using this.

Specifically, the dissolution test is performed as follows. An active energy ray-curable ink containing the photopolymerization initiator (A) and the diallyl phthalate resin (B) is applied to the ink receiving layer of the substrate (P) by an RI tester at 1.6 × 10 ⁻⁴ g / cm ^2. After the color was developed, a cured film (Q) that was irradiated and cured was formed at a conveyor speed of 300 m / min (ultraviolet irradiation integrated light amount = 10 mJ / cm ² ) using a metal halide lamp irradiation device at 20 cm under an 80 W lamp. The cured film surface of the base material (p1) provided with the cured film cut to an area of 600 cm ² and the resin layer surface of the base material (p2) not provided with the cured film having the same area are superposed. After leaving still for 48 hours in an environment of 25 ° C. and 50% RH at a load of 5 kg / cm ^2, the base material (p2) was placed in 1000 ml of 95% ethanol aqueous solution in an environment of 25 ° C. and 50% RH. Soaked for hours , Using a liquid chromatograph mass spectrometer, present in ethanol obtaining the elution total concentration of the photoinitiator. The RI tester is a tester that develops ink on paper or film, and can adjust the amount of ink transferred and the printing pressure.

  According to the dissolution test, the total concentration of the photopolymerization initiator eluted is preferably less than 100 ppb, more preferably less than 30 ppb, and even more preferably 0 ppb. Note that the value below the detection limit is 0 ppb.

  The odor on the surface of the cured film forms a cured film (Q) under the same conditions as in the elution test, and the presence or absence of the odor emitted from the surface of the cured film is evaluated by sensory evaluation.

  In addition, although the said elution test was performed about the grade (migration | transfer) of the photoinitiator to the surface which has not formed the cured film, it is from the surface (cured film surface) itself which formed the cured film. It is also preferred that the elution concentration of the photopolymerization initiator is lower. The degree of elution concentration from the cured film surface itself depends on the accumulated amount of ultraviolet irradiation. That is, the larger the UV irradiation integrated light amount, the less the unreacted photopolymerization initiator, so the elution concentration becomes smaller, and the smaller the UV irradiation integrated light amount, the more unreacted photopolymerization initiator, the elution concentration. Tend to be larger.

In general, curing and drying of the active energy ray-curable ink is performed by appropriately determining an integrated amount of ultraviolet irradiation using an ultraviolet irradiation device or the like, and irradiating ultraviolet rays or the like. Ultraviolet irradiation equipment includes high pressure mercury lamp irradiation equipment, ultra high pressure mercury lamp irradiation equipment, xenon lamp irradiation equipment, metal halide lamp irradiation equipment, ozone-less metal halide lamp irradiation equipment, LED-UV lamp irradiation equipment and low power consumption ultraviolet fluorescent lamp irradiation equipment. Etc. Conventional active energy ray curable inks cure and dry well when the UV irradiation cumulative light quantity is about 40-60 mJ / cm ² , but low energy curable inks that cure and dry under low irradiation energy conditions are UV irradiation. It cures and dries well when the integrated light quantity is about 10 to ²⁰ mJ / cm ² . That is, in actual printing sites, it is generally performed to sufficiently irradiate ultraviolet rays in order to cure and dry the active energy ray curable ink, but there are few due to requests such as reduction of energy cost and shortening of irradiation time. Curing and drying are possible even with UV irradiation accumulated light quantity, and curing is sufficiently stable against fluctuations in UV irradiation accumulated light quantity, and the elution concentration of the photopolymerization initiator from the cured film is small, and those with little fluctuation are preferred. .

Therefore, a photopolymerization initiator that satisfies the following conditions (hereinafter also simply referred to as “photopolymerization initiator (A ′)”) is preferable.
On the surface of the ink-receiving layer of the substrate (P), it is applied at 1.6 × 10 ⁻⁴ g / cm ² , and using the ultraviolet irradiation device, the ultraviolet irradiation integrated light amount is 10 mJ / cm ² and 95 mJ / cm ^2. under conditions such that the, irradiated with ultraviolet rays, respectively cured film _{(q 10), (q 95} ) and then, cured film _{(q 10)} a provided substrate cut to an area of 600cm ² _{(p 10)} and the area The base material (p ₉₅ ) provided with the cured film (q ₉₅ ) was immersed in 1000 ml of 95% ethanol aqueous solution for 24 hours in an environment of 25 ° C. and 50% RH, and then a liquid chromatograph mass spectrometer was used. When the elution concentrations (d ₁₀ ) and (d ₉₅ ) of the photopolymerization initiator (A ′) present in ethanol were measured, the elution concentration (d ₁₀ ) was 4000 ppb or less and the ratio of elution concentrations ( _{d 10)} / (d ₉ ) Is preferably 1.6 or less. More preferably, (d ₁₀ ) is 3000 ppb or less, and the ratio of elution concentrations (d ₁₀ ) / (d ₉₅ ) is 1.1 or less.
Within this range, even if the curing conditions (ultraviolet irradiation integrated light quantity) vary, the cured film is sufficiently cured, the elution concentration of the photopolymerization initiator (A ′) is small, and the variation is small. Is obtained. Here, as a condition for the ultraviolet irradiation integrated light amount to be 10 mJ / cm ² , using a metal halide lamp irradiation device, the conveyor speed is 300 m / min with 20 cm under the 80 W lamp, and the ultraviolet irradiation integrated light amount is 95 mJ / cm ² . As a condition for this, the conveyor speed is 30 m / min.

  Examples of the photopolymerization initiator (A ′) include 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2- Methyl-1-phenylpropan-1-one, phenylglyoxylic acid methyl ester, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- [2-hydroxyethoxy] ethyl ester 2,4-diethylthioxanthone, 4, '- bis (diethylamino) benzophenone, o- benzoyl methyl benzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid 2-ethylhexyl and the like. Among them, 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, phenylglyoxylic acid Methyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] Mixture of ethyl ester and oxyphenylacetic acid, 2- [2-hydroxyethoxy] ethyl ester, 4,4′-bis (diethylamino) benzophenone, methyl o-benzoylbenzoate, ethyl 4-dimethylaminobenzoate, 4-dimethyl 2-ethylhexyl aminobenzoate Preferred. Further, there is no odor when cured, and 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 4,4′-bis (diethylamino) benzophenone.

Specifically, 4 parts of the photopolymerization initiator (A ′) is added to and mixed with the base ink containing diallyl phthalate resin to prepare a test ink. However, a photopolymerization initiator that is not cured by itself (for example, 4,4′-bis (diethylamino) benzophenone, etc.) is mixed with another photopolymerization initiator that is cured to obtain a test ink. After the test ink was developed on the ink receiving layer of the base material (P) with an RI tester at 1.6 × 10 ⁻⁴ g / cm ² , the conveyor speed was increased by 20 cm under an 80 W lamp using a metal halide lamp irradiation device. Irradiated and cured cured films (q ₁₀ ) and (q ₉₅ ) are formed at 300 m / min (ultraviolet irradiation integrated light amount = 10 mJ / cm ² ) and a conveyor speed of 30 m / min (ultraviolet irradiation integrated light amount = 95 mJ / cm ² ). The base material (p ₁₀ ) provided with the cured film (q ₁₀ ) cut to an area of 600 cm ² and the base material (p ₉₅ ) provided with the cured film (q ₉₅ ) of the same area were each 95% ethanol. After being immersed in 1000 ml of an aqueous solution in an environment of 25 ° C. and 50% RH for 24 hours, using a liquid chromatograph mass spectrometer, a photopolymerization initiator (A ′ Each elution concentration _(d 10), determine the _{(d 95).}

  The diallyl phthalate resin (B) is orthotype (b1) and isotype (b2), and (b1) :( b2) is preferably 5:95 to 95: 5 by weight. If the isotype (b2) is more than this, the active energy ray curability of the ink is lowered, and if it is less, the fluidity of the ink is lowered. More preferably, it is 10: 90-90: 10 parts. By being within this range, the balance between ink fluidity and curability is good.

  Furthermore, it is preferable to contain a gloss improver. By adding the gloss improver, the gloss of the multicolored portion of the printed matter is remarkably improved. Even when the uppermost layer is not yellow but is indigo or red, the same effect can be obtained if the uppermost layer ink contains a gloss improver. The same effect can be obtained even when the uppermost layer is an overprint varnish containing a gloss improver.

  The gloss improver preferably contains a dibasic acid ester, and the dibasic acid ester is preferably an ester of a dibasic acid having 2 to 18 carbon atoms and a monoalcohol.

The dibasic acid ester is obtained by esterifying a dibasic acid having a carboxyl group at both ends having 2 to 18 carbon atoms and a monoalcohol.
Examples of the dibasic acid having 2 to 18 carbon atoms include the following.
Oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecane Examples include diacid, hexadecanedioic acid, heptadecanedioic acid, and octadecanedioic acid.

  Examples of the dibasic acid ester include oxalic acid ester, malonic acid ester, succinic acid ester, fumaric acid ester, maleic acid ester, glutaric acid ester, adipic acid ester, pimelic acid ester, phthalic acid ester, azelaic acid ester, and sebacic acid. One or two selected from ester, undecanedioic acid ester, dodecanedioic acid ester, tridecanedioic acid ester, tetradecanedioic acid ester, pentadecanedioic acid ester, hexadecanedioic acid ester, heptadecanedioic acid ester and octadecanedioic acid ester It is preferable to contain seeds or more. The dibasic acid ester is preferably a diester rather than a monoester.

Furthermore, the monoalcohol is a monoalcohol having 1 to 13 carbon atoms. The monoalcohol preferably has a saturated hydrocarbon chain which may be linear or branched.
Examples of the monoalcohol having 1 to 13 carbon atoms include the following.
Methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, n-pentyl alcohol, sec-pentyl alcohol, tert-pentyl alcohol, neopentyl alcohol , Isopentyl alcohol, sec-isoamyl alcohol, 2-methylbutyl alcohol, n-hexyl alcohol, sec-hexyl alcohol, isohexyl alcohol, tert-isohexyl alcohol, methylpentyl alcohol, 1,1-diethyl alcohol, 1-ethyl Butyl alcohol, 2-ethylbutyl alcohol, 3,3-dimethylbutyl alcohol, pinacolyl alcohol, n-heptyl alcohol Tert-heptyl alcohol, 1-methylhexyl alcohol, 1-propylbutyl alcohol, n-octyl alcohol, isooctyl alcohol, sec-octyl alcohol, 2-ethylhexyl alcohol, n-nonyl alcohol, isononyl alcohol, 1-butylpentyl Alcohol, n-decyl alcohol, isodecyl alcohol, 1-methylnonyl alcohol, 3,7-dimethyloctyl alcohol, hedecyl alcohol, 2-hendecyl alcohol, 3-hendecyl alcohol, n-dodecyl alcohol, n-tridecyl Examples include alcohol and 1,1-dibutylpentyl alcohol. Of these, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, n-pentyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, 2-ethylhexyl alcohol and the like are more preferable. .

  Examples of oxalate esters include dioctyl oxalate, di-2-ethylhexyl oxalate, diisononyl oxalate, diisodecyl oxalate, and maleate esters such as di-n-butyl maleate, dipentyl maleate, dihexyl maleate, and maleic acid. Diheptyl, dioctyl maleate, di-2-ethylhexyl maleate, diisononyl maleate, diisodecyl maleate, adipic acid ester include di-n-butyl adipate, dipentyl adipate, dihexyl adipate, diheptyl adipate, adipic acid Dioctyl, di-2-ethylhexyl adipate, diisononyl adipate, diisodecyl adipate, phthalate esters include di-n-butyl phthalate, dipentyl phthalate, diheptyl phthalate, phthalate Dihexyl, dioctyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, diisodecyl phthalate, azelaic acid ester include dipropyl azelate, di-n-butyl azelate, dipentyl azelate, dihexyl azelate, azelaic acid Diheptyl, dioctyl azelate, di-2-ethylhexyl azelate, diisononyl azelate, diisodecyl azelate, sebacate, dimethyl sebacate, diethyl sebacate, dipropyl sebacate, di-n-butyl sebacate, sebacate Dipentyl, dihexyl sebacate, diheptyl sebacate, dioctyl sebacate, di-2-ethylhexyl sebacate, diisodecyl sebacate, diisononyl sebacate, dode Didecanoic acid dipropyl, dodecanedioic acid di-n-butyl, dodecanedioic acid dipentyl, dodecanedioic acid dihexyl, dodecanedioic acid diheptyl, dodecanedioic acid dioctyl, dodecanedioic acid di-2-ethylhexyl, Mention may be made of didecanonyl dodecanedioate and diisodecyl dodecanedioate. Among them, dioctyl oxalate, di-2-ethylhexyl oxalate, diisononyl oxalate, diisodecyl oxalate, di-n-butyl maleate, dipentyl maleate, dihexyl maleate, diheptyl maleate, dioctyl maleate, di- maleate 2-ethylhexyl, di-n-butyl adipate, dipentyl adipate, dihexyl adipate, diheptyl adipate, dioctyl adipate, di-2-ethylhexyl adipate, di-n-butyl phthalate, dipentyl phthalate, phthalic acid Diheptyl, dihexyl phthalate, dioctyl phthalate, di-2-ethylhexyl phthalate, di-n-butyl azelate, dipentyl azelate, dihexyl azelate, diheptyl azelate, dioctyl azelate, azela Di-2-ethylhexyl acetate, dimethyl sebacate, diethyl sebacate, di-n-butyl sebacate, dipentyl sebacate, dihexyl sebacate, diheptyl sebacate, dioctyl sebacate, di-2-ethylhexyl sebacate, dodecane Gloss improvement effect of dimethyl acid, diethyl dodecanedioate, di-n-butyl dodecanedioate, dipentyl dodecanedioate, dihexyl dodecanedioate, diheptyl dodecanedioate, dioctyl dodecanedioate, di-2-ethylhexyl dodecanedioate Is preferable. Particularly preferred are di-n-butyl adipate, dipentyl adipate, dihexyl adipate, diheptyl adipate, dioctyl adipate, di-2-ethylhexyl adipate, di-n-butyl phthalate, dipentyl phthalate, phthalate Diheptyl acid, dihexyl phthalate, dioctyl phthalate, di-2-ethylhexyl phthalate, dimethyl sebacate, diethyl sebacate, di-n-butyl sebacate, dipentyl sebacate, dihexyl sebacate, diheptyl sebacate, dioctyl sebacate And di-2-ethylhexyl sebacate. When the total number of carbon atoms of the dibasic acid diester is 10 or less, the solubility with the resin is low, the ink becomes cloudy, and the effect of improving gloss is reduced.

  The gloss improver is more effective as the amount added is increased in the ink, but is preferably 0.1 to 6% by mass. If the amount of the gloss improving agent is less than 0.1% by mass, the effect of improving the gloss is not recognized. If it exceeds 6% by mass, the curability by the active energy ray is lowered, and smearing is likely to occur during printing. More preferably, the addition amount of the gloss improver is 0.5 to 3% by mass in the ink. An ink composition having good printability can be obtained, and a printed matter having excellent gloss of a multicolored portion when printed can be obtained.

  The gloss improver is preferably contained in at least the uppermost ink of the active energy ray-curable ink. Usually, in the case of process ink, since multi-color overprinting of ink is performed in the order of black, indigo, red, and yellow, the yellow ink layer is the uppermost layer and forms a printing portion. It is considered that the gloss was increased because the surface of the uppermost layer was flattened with a yellow ink to which a gloss improver was added. By adding the gloss improver, the gloss of the multicolored portion of the printed matter is remarkably improved. Even in the case where the uppermost layer is not yellow but is indigo, red or other color, the same effect can be obtained if the uppermost layer ink contains a gloss improver. The same effect can be obtained even when the uppermost layer is an overprint varnish containing a gloss improver.

  Furthermore, it is preferable to contain an ethylenically unsaturated compound.

  The ethylenically unsaturated compound is a monomer or oligomer that is polymerized by irradiation with active energy rays, and is preferably a compound having a (meth) acryl group (hereinafter also referred to as (meth) acrylate). The ethylenically unsaturated compound may be a monofunctional (meth) acrylate or a polyfunctional (meth) acrylate. Further, urethane (meth) acrylate and polyester (meth) acrylate may be used.

  Examples of monofunctional (meth) acrylates include phenoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, tricyclodecane monomethylol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl Examples include (meth) acrylate. Examples of polyfunctional (meth) acrylates include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) Acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene di (meth) acrylate, butylene glycol di (meth) acrylate, pentyl glycol di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, 1,7-heptanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, , 2-octanediol di (meth) acrylate di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 1,12-dodecanediol di (meth) Bifunctional (meth) acrylates such as acrylate, tricyclodecane dimethylol di (meth) acrylate, tricyclodecane dimethylol dicaprolactonate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin tri (meta) ) Acrylate, glycerin propoxytri (meth) acrylate, pentaerythritol tri (meth) acrylate and other trifunctional (meth) acrylates, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) Acrylate, pentaerythritol tetracaprolactonate tetra (meth) acrylate, diglycerin tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, Examples include tetrafunctional or higher polyfunctional (meth) acrylates such as tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tripentaerythritol polyalkylene oxide hepta (meth) acrylate, and the like.

  Moreover, the (meth) acrylate of the polyol which has a C1-C18 alkyl group may be sufficient. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and isobornyl (meta) ) Monofunctional (meth) acrylates such as acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di ( (Meth) acrylate, pentyl glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalyl hydroxypivalate di (meth) acrylate Todi (meth) acrylate, hydroxypivalyl hydroxypivalate dicaprolactonate di (meth) acrylate, hexanediol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, tricyclodecane dimethylol dicaprolactonate Di (meth) acrylate, bisphenol A tetrapropylene oxide adduct di (meth) acrylate, bisphenol A polyalkylene oxide adduct di (meth) acrylate, bisphenol F tetrapropylene oxide adduct di (meth) acrylate, bisphenol F polyalkylene oxide Adduct di (meth) acrylate, bisphenol S tetraethylene oxide adduct di (meth) acrylate, bisphenol S polyalkylene oxide Adduct di (meth) acrylate, water-added bisphenol A tetrapropylene oxide adduct di (meth) acrylate, water-added bisphenol A polyalkylene oxide adduct di (meth) acrylate, water-added bisphenol F tetrapropylene oxide adduct di (meth) ) Acrylate, water-added bisphenol F polyalkylene oxide adduct di (meth) acrylate, water-added bisphenol A di (meth) acrylate, water-added bisphenol F di (meth) acrylate, dihydroxybenzene (catechol, resorcin, hydroquinone, etc.) polyalkylene Oxide di (meth) acrylate, alkyldihydroxybenzene polyalkylene oxide di (meth) acrylate, bisphenol A tetraethylene oxide adduct dica Bifunctional (meth) acrylates such as prolactonate di (meth) acrylate, bisphenol F tetraethylene oxide adduct dicaprolactonate di (meth) acrylate, glycerin poly (2-20) alkylene (C2-C20) oxide addition (As alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tri (meth) acrylate, trimethylolpropane poly (2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene Oxide, butylene oxide) tri (meth) acrylate, trimethylolethane poly (2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide) For example, trifunctional (meth) acrylate such as ethylene oxide, propylene oxide, butylene oxide) tri (meth) acrylate, pentaerythritol poly (2-20) alkylene (C2-C20) oxide adduct (alkylene oxide, for example, ethylene oxide , Propylene oxide, butylene oxide) tetra (meth) acrylate, diglycerin poly (2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tetra (meth) acrylate , Diglycerin poly (2-20) alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide) adduct tetra ( ) Acrylate, ditrimethylolpropane poly (2-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tetra (meth) acrylate, ditrimethylolpropane poly (2- 20) Alkylene oxide (for example, ethylene oxide, propylene oxide, butylene oxide, etc.) tetra (meth) acrylate, ditrimethylolpropane tetracaprolactonate, tetra (meth) acrylate, ditrimethylolethane poly (2-20) alkylene (C2- C20) Oxide adduct (As alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) tetra (meth) acrylate And polyfunctional (meth) acrylates having 4 or more functional groups such as cartons.

  The ethylenically unsaturated compound may be epoxidized vegetable oil (meth) acrylate. Epoxidized vegetable oil (meth) acrylate is a compound obtained by ring-opening addition polymerization of (meth) acrylic acid to the epoxy group of epoxidized vegetable oil epoxidized with peracetic acid and perbenzoic acid to the double bond of unsaturated vegetable oil. . The unsaturated vegetable oil is a triglyceride in which at least one fatty acid is a fatty acid having at least one carbon-carbon unsaturated bond in the triglyceride of glycerin and a fatty acid. Oil, linseed oil, coconut oil, oil deer oil, olive oil, cacao oil, kapok oil, kayak oil, coconut oil, apricot oil, tung oil, kukui oil, walnut oil, poppy oil, sesame oil, safflower oil, radish seed oil, large Bean oil, dairy oil, coconut oil, rapeseed oil, niger oil, nuka oil, palm oil, castor oil, sunflower oil, grape seed oil, tonsils oil, pine seed oil, cottonseed oil, coconut oil, peanut oil, dehydrated castor oil Etc. Examples of the epoxidized vegetable oil (meth) acrylate include epoxidized soybean oil (meth) acrylate (CN111 manufactured by Sartomer, EBECRYL860 manufactured by Daicel Ornex Co., Ltd., Photomer 3005 manufactured by iGMRESINS), and the like.

  Among them, ethylenically unsaturated compounds used in the present invention are phenoxyethyl acrylate, cyclohexyl (meth) acrylate, ethoxydiethylene glycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol. Di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, tri Methylolpropane tri (meth) acrylate, glycerin propoxytri (meth) acrylate, pentaerythritol tri (meth) acrylate, di Limethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane 3EO modified tri (meth) acrylate, bisphenol A4EO modified di (Meth) acrylate, bisphenol A10EO modified di (meth) acrylate, trimethylolpropane 6EO modified tri (meth) acrylate, trimethylolpropane 9EO modified tri (meth) acrylate, trimethylolpropane 3PO modified tri (meth) acrylate, pentaerythritol EO It is modified tetra (meth) acrylate, epoxidized soybean oil (meth) acrylate, polyester (meth) acrylate It is preferred. In particular, in the case of an environment-friendly type, epoxidized soybean oil (meth) acrylate is more preferable.

  The ethylenically unsaturated compound is preferably contained in the ink in an amount of 30 to 70% by mass, and more preferably 40 to 60% by mass. If the amount of the ethylenically unsaturated compound is less than 30% by mass, sufficient printability cannot be obtained, and if it exceeds 70% by mass, the pigment solid content decreases and the concentration decreases. When the addition amount of the ethylenically unsaturated compound is within the above range in the ink, an active energy ray-curable ink having no white turbidity, good curability and good printability can be obtained.

  Furthermore, it is preferable to contain a pigment.

  Examples of the pigment include organic pigments and inorganic pigments, such as organic pigments typified by disazo yellow, carmine 6B, phthalocyanine blue, and inorganic pigments typified by carbon black, calcium carbonate, and the like, and are not particularly limited. .

  Furthermore, you may contain other photoinitiators other than said (A) and (A ').

  Although the kind and content of a photoinitiator can be suitably selected according to the kind of ethylenically unsaturated compound and the active energy ray to irradiate, it is preferable to select the thing which a migration does not occur easily.

The photopolymerization initiator other than (A) and (A ′) is particularly preferably a compound capable of generating a substance that initiates radical polymerization by irradiation with active energy rays. Examples of photopolymerization initiators include 2-methyl-1- [4- (methylthio) phenyl] -2- (4-morpholinyl) -1-propanone, 2-methyl-1- [4- (2-hydroxyethoxy) ) Phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 4-phenylbenzophenone, 1- [4- (4-benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methyl) Phenylsulfonyl) propan-1-one, 4-benzoyl-4′-methyldiphenyl sulfide, bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H— Pyrrol-1-yl) phenyl) titanium, 1,2-octanedione, 1- [4- (phenylthio)-, 2- (o-benzoyloxime)], ethanone, 1 [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (o-acetyloxime), 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, benzophenone, trimethylbenzophenone, methylbenzophenone, Isopropylthioxanthone, methyl 4-phenylbenzophenone, o-benzoylbenzoate, 4-, 4'-dichlorobenzophenone, hydroxybenzophenone, acrylated benzophenone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone 3,3′-dimethyl-4-methoxy Benzophenone, 2,2-dimethyl-2-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, Michler's ketone, trimethylbenzophenone, methylbenzophenone mixture, 2-isopropylthioxanthone, 2,4-dichlorothioxanthone, L-chloroform-4 -Propoxythioxanthone, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, L-phenyl-2-hydroxy-2-methylpropanone, 10-butyl-2-chloroacridone, Examples include 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone, 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer, and the like.

  The total amount of the photopolymerization initiators (A), (A ′) and other photopolymerization initiators is preferably 6 to 25% by mass in the ink. When the total amount of the photopolymerization initiators (A), (A ′) and other photopolymerization initiators is less than 6% by mass, the curability is inferior. When the total amount exceeds 25% by mass, the pigment solid content decreases and the concentration decreases. End up. More preferably, it is 10-15 mass% in ink. An ink having good printability can be obtained, and a printed matter with less odor can be obtained when printing with a multicolor set.

  Moreover, the photosensitizer may be included. Examples of photosensitizers include triethanolamine, methyldiethanolamine, triisopropanolamine, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, and 4-dimethylaminobenzoic acid (n-butoxy) ethyl. And amine compounds. The addition amount of these photosensitizers is preferably 0.01 to 10% by mass in the ink. These photosensitizers may be used alone or in combination of two or more.

  The printed matter of the present invention can be used as long as it is a substrate to which the active energy ray-curable ink of the present invention is adhered, and can be produced by ordinary offset printing.

  As the base material used for the printed matter of the present invention, in particular, the ink is used on the base paper of milk carton paper, cardboard paper, coated cardboard paper, Manila cardboard paper, Kent paper, aluminum vapor-deposited paper, synthetic paper (Yupo paper) having a thickness of 2 mm or less. Those provided with a receiving layer are preferably used.

  The food packaging container of the present invention can be produced from a printed matter printed on the substrate. In particular, a printed material using a base material made of milk carton paper, cardboard paper, coated cardboard, or manila cardboard is preferably used as a food packaging container. The form of the food packaging container may be any known form used for food packaging such as Tetra Pak, Gable Top, Brick, Cup, Tray.

  The active energy ray-curable ink of the present invention can be preferably used as an ink having a viscosity of 20 Pa · s to 70 Pa · s at 25 ° C. Viscosity is a numerical value measured with an L-type viscometer in accordance with JIS K5701-1: 2000. When the viscosity is lower than 20 Pa · s, even if the gloss improver of the present invention is contained, the effect of improving gloss is hardly exhibited, and when the viscosity exceeds 70 Pa · s, printing cannot be performed well, and a glossy printed matter may not be obtained. There is.

  The active energy ray in the present invention represents energy required for the starting material of the curing reaction to be excited from the ground state to the transition state, and the active energy ray in the present invention refers to ultraviolet rays or electron beams.

  The photocuring method of active energy ray curable ink is generally an electroded high-pressure mercury lamp, electroded metal halide lamp, electrodeless high-pressure mercury lamp, electrodeless metal halide lamp, ozoneless metal halide lamp, xenon lamp, LED-UV lamp. A light source that emits ultraviolet rays such as a low power consumption ultraviolet fluorescent lamp is used. In particular, an LED-UV lamp that is irradiated with low energy can also be suitably used.

  The production of the active energy ray curable ink of the present invention may be carried out by the same method as that of the conventional active energy ray curable ink. For example, a resin, a photopolymerization initiator, and a gloss improver between room temperature and 100 ° C. Ink components such as ethylenically unsaturated compounds, pigments, extender pigments, polymerization inhibitors, amine compounds, and other additives, kneaders such as kneaders, three rolls, attritors, sand mills, gate mixers, Manufactured using a mixing and adjusting machine.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these. In addition, the part in an Example and a comparative example represents a weight part, and% represents the mass%.

<Production of varnish>

(Reference Example 1)
24 parts of diallyl (ortho) phthalate resin (Daiso Dup A, manufactured by Daiso Corporation), 49.9 parts of dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.), ditrimethylolpropane tetraacrylate (Miramer 410) ), 26 parts, and 0.1 part of a polymerization inhibitor (Q-1301, manufactured by Wako Pure Chemical Industries, Ltd.) were blended to obtain varnish 1.

(Reference Example 2)
Diallyl (iso) phthalate resin (Daiso Isodap, manufactured by Daiso Corporation) 24 parts, Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku Co., Ltd.) 49.4 parts, Ditrimethylolpropane tetraacrylate (Miramer 410) 26 parts), polymerization inhibitor (Q-1301, Wako Pure Chemical Industries, Ltd.) 0.1 part, aluminum ethyl acetoacetate diisopropylate 0.5 part, and varnish 2 is obtained. It was.

In the following combination, 4 parts of each photopolymerization initiator was blended with the base ink to prepare test inks 1 to 5 as shown in Table 1.
(Base ink)
Varnish 1 34.5 parts Varnish 2 11.5 parts Dipentahexaacrylate 11.5 parts Ditrimethylolpropane tetraacrylate 15 parts Carmine 6B (Sumika Print Carmine 6BC 300 Super, manufactured by Sumika Color Co., Ltd.) 24 parts Magnesium carbonate ( Magnesium carbonate TT, manufactured by Naikai Shigyo Co., Ltd.) 3.5 parts (test initiator 1)
2-Methyl-1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one 2- (dimethylamino) -2-[(4-methylphenyl) methyl ] -1- [4- (4-morpholinyl) phenyl] -1-butanone 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Test Initiator 2)
2-Methyl-1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one 2-hydroxy-2-methyl-1-phenylpropan-1-one 2 -Hydroxy-1- [4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl] -2-methylpropan-1-one oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy ] Mixture of ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) ethyl ester (Test Initiator 3)
Phenylglyoxylic acid methyl ester oligo (2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone 2-hydroxy-1- [4- [4- (2-hydroxy-2- Methylpropionyl) phenoxy] phenyl] -2-methylpropanone bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (test initiator 4)
1-hydroxycyclohexyl phenyl ketone 2,2-dimethoxy-1,2-diphenylethane-1-one o-benzoylmethyl 4-benzoylbenzoate 2-ethylhexyl benzoate (test initiator 5)
2-Benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone 2,4-diethylthioxanthone 4,4′-bis (diethylamino) benzophenone 4-dimethylaminoethyl benzoate

<Migration test of photopolymerization initiator>
Test inks 1 to 5 with a thickness of 0.5 mm milk carton paper (polyethylene resin coat, single-sided corona treatment, manufactured by Nippon Paper Industries Co., Ltd.) (see FIG. 1 (a)) 1.6 × with a RI tester. After ^{spreading at} 10 ⁻⁴ g / cm ² , using a metal halide lamp irradiator, cured by irradiation and curing at a conveyor speed of 300 m / min (ultraviolet light irradiation integrated light amount = 10 mJ / cm ² ) with 20 cm under an 80 W lamp. A film is formed (see FIG. 1B), which is cut into an area of 600 cm ² to obtain a test piece, while the milk carton paper not provided with a cured film is similarly cut into an area of 600 cm ² to obtain a blank paper As a test piece, the cured film surface of the test piece and the resin layer surface of the blank paper test piece are overlapped (see FIG. 1 (c)), and an environment of 25 ° C. and 50% RH is applied at a load of 0.5 kg / cm ^2. 48 After leaving still for a period of time (see FIG. 1 (d)), the blank paper test piece was immersed in 1000 ml of 95% ethanol aqueous solution for 24 hours in an environment of 25 ° C. and 50% RH, and then using a liquid chromatograph mass spectrometer. The total elution concentration of the photopolymerization initiator present in ethanol was determined. The value below the detection limit was also described as 0 ppb. The results are shown in Table 2.
Moreover, sensory evaluation was performed about the odor emitted from the cured film surface immediately after hardening. The results are shown in Table 2. The printed surface immediately after curing was touched with a finger and it was confirmed that there was no stickiness.

  From the results in Table 2, 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2-[(4-methylphenyl) methyl]- 1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 4,4 The photopolymerization initiator of '-bis (diethylamino) benzophenone has no odor and is very effective because it has good migration (difficult to migrate) even with a small amount of accumulated UV light. .

<Elution dependence test of photopolymerization initiator>
The test inks 1 to 5 are applied to a corona-treated surface of milk carton paper (polyethylene resin coat, single-sided corona treatment, Nippon Paper Industries Co., Ltd.) having a thickness of 0.5 mm with an RI tester at 1.6 × 10 ⁻⁴ g / cm ² . After the color development, using a metal halide lamp irradiation device, the conveyor speed is 300 m / min (ultraviolet irradiation integrated light quantity = 10 mJ / cm ² ) and the conveyor speed is 30 m / min (ultraviolet irradiation integrated light quantity = 95 mJ / cm) with 20 cm under the 80 W lamp. ^{In 2} ), a cured film cured by irradiation was formed, and this was cut into an area of 600 cm ² to obtain a test piece. The test specimen was immersed in 1000 ml of 95% ethanol aqueous solution for 24 hours in an environment of 25 ° C. and 50% RH, and then the elution concentration of the photopolymerization initiator present in ethanol using a liquid chromatograph mass spectrometer ( d ₁₀ ), (d ₉₅ ) and elution concentration ratio (d ₁₀ ) / (d ₉₅ ) were determined. The value below the detection limit was also described as 0 ppb. The printed surface immediately after curing was touched with a finger and it was confirmed that there was no stickiness. The results are shown in Table 3.

From the results in Table 3, 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, phenylglycol Oxylic acid methyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, oxyphenylacetic acid, 2- [2-oxo-2-phenyl Acetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) ethyl ester, 4,4′-bis (diethylamino) benzophenone, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid 2 -UV light with less ethylhexyl photopolymerization initiator It is recognized that the elution concentration is small in the integrated light quantity ((d ₁₀ ) ≦ 3000 ppb), and the variation in the elution concentration is small and favorable ((d ₁₀ ) / (d ₉₅ ) ≦ 1.1) with respect to the variation in the curing conditions. And was very effective.

<Production of active energy ray curable red ink>
Example 19 having a viscosity value of 35 to 45 Pa · s by an L-type viscometer (25 ° C.) according to the composition shown in Table 4 by adding and mixing a photopolymerization initiator, a gloss improver, and the like using the base ink. To 28 and Comparative Examples 19 to 20 were obtained.

  The following table test was performed about each active energy ray hardening type | mold red ink of Examples 19-28 and Comparative Examples 19-20. The results are shown in Table 5.

<Evaluation of curability>
Each ink was developed at 1.6 × 10 ⁻⁴ g / cm ² using a RI tester on the corona-treated surface of 0.5 mm thick milk carton paper (polyethylene resin coat, single-sided corona treatment, Nippon Paper Industries Co., Ltd.). Then, 20 cm under the metal halide lamp 80 W was irradiated and cured at a conveyor speed of 300 m / min (ultraviolet irradiation integrated light amount = 10 mJ / cm ² ), and the printed surface immediately after curing was touched with a finger to evaluate the presence or absence of stickiness. ○: No stickiness, Δ: Slightly sticky (no problem in practical use), ×: Stickiness evaluated.

<Evaluation of migration (low migration)>
Each ink was developed at 1.6 × 10 ⁻⁴ g / cm ² using a RI tester on the corona-treated surface of 0.5 mm thick milk carton paper (polyethylene resin coat, single-sided corona treatment, Nippon Paper Industries Co., Ltd.). Then, a cured film formed by irradiation and curing at a conveyor speed of 300 m / min (ultraviolet irradiation integrated light amount = 10 mJ / cm ² ) by 20 cm under the lamp of the metal halide lamp 80W is formed, and this is cut into an area of 600 cm ² to obtain a test piece. On the other hand, the milk carton paper without a cured film is similarly cut into an area of 600 cm ² to obtain a blank paper test piece, and the cured film surface of the test piece and the resin layer surface of the blank paper test piece are overlapped to obtain 0.5 kg / cm. ^After leaving for 48 hours in an environment of 25 ° C. and 50% RH under a load of ^2, the blank paper test piece was placed in 1000 ml of 95% ethanol aqueous solution at 25 ° C. and 50% R. After immersion for 24 hours in an H environment, the total elution concentration of the photopolymerization initiator present in ethanol was determined and evaluated using a liquid chromatograph mass spectrometer. The lower the total concentration of elution, the better the migration (low migration). A: Total elution concentration of photopolymerization initiator is less than 50 ppb, O: Total elution concentration of photopolymerization initiator is 50 ppb or more and less than 100 ppb, X: Total elution concentration of photopolymerization initiator is evaluated in three stages: 100 ppb or more .

<Evaluation of odor>
Each ink was developed at 1.6 × 10 ⁻⁴ g / cm ² using a RI tester on the corona-treated surface of 0.5 mm thick milk carton paper (polyethylene resin coat, single-sided corona treatment, Nippon Paper Industries Co., Ltd.). Then, it was cured by irradiation at a conveyor speed of 300 m / min (ultraviolet irradiation integrated light amount = 10 mJ / cm ² ) by 20 cm under a metal halide lamp 80 W to form a cured film, thereby obtaining a sample piece. The sensory evaluation was performed about the odor emitted from the cured film of the sample piece immediately after hardening. ○: No odor at all, Δ: Little odor (no problem in practical use), ×: Odor, XX: Unpleasant odor

  From the data in Table 5, it was confirmed that the inks of Examples 19 to 28 were very good in terms of curability, transferability and odor. Therefore, it is clear that even with a low UV integrated light amount, the curability is sufficient and the transition is difficult. Comparative Example 19 using a photopolymerization initiator similar to Cited Document 2 has good curability and migration, but 2-hydroxy-1- [4- [4- (2-hydroxy-2-methylpropionyl). Odor due to benzyl) phenyl] -2-methylpropan-1-one was confirmed. This is because the content of the photopolymerization initiators (a1) and (a2) is low, so that 2-hydroxy-1- [4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl] -2- It was judged to be a result of supplementing curability by adding methylpropan-1-one. Further, Comparative Example 20, which is a conventional example, has good curability, but migration of 2-methyl-1- [4- (methylthio) phenyl] -2- (4-morpholinyl) -1-propanone was confirmed. Moreover, the odor derived from the photoinitiator was confirmed.

<Preparation of active energy ray-curable yellow ink>
Except having changed the red pigment to the yellow pigment, Examples 29 to 33 having a viscosity value of 35 to 45 Pa · s by an L-type viscometer (25 ° C.) according to the composition of Table 6 under the same conditions as the above red ink And the active energy ray hardening-type yellow inks 1-6 of the comparative example 21 were obtained.

<Production of active energy ray curable indigo ink>
Examples 34 to 37 having a viscosity value of 35 to 45 Pa · s as measured by an L-type viscometer (25 ° C.) according to the composition shown in Table 7 under the same conditions as the above red ink except that the red pigment was changed to an indigo pigment. And the active energy ray hardening-type indigo inks 1-5 of the comparative example 22 were obtained.

<Preparation of active energy ray-curable black ink>
Examples 38 to 40 having a viscosity value of 35 to 45 Pa · s according to an L-type viscometer (25 ° C.) according to the composition shown in Table 8 under the same conditions as the above red ink except that the red pigment was changed to a black pigment. And the active energy ray hardening-type black ink 1-4 of the comparative example 23 was obtained.

  About each ink of Examples 29-40 and Comparative Examples 21-23, evaluation of sclerosis | hardenability, transferability, and an odor was performed similarly to the said red ink. The results are shown in Table 9.

  From the data in Table 9, each of the inks of Examples 29 to 40 has a curability equivalent to that of Comparative Examples 21 to 23, which is a conventional example, is excellent in migration (low migration), and is suppressed in odor. Was confirmed.

<Production of active energy ray-curable red ink>
Except for changing the red pigment to a red pigment (valve), under the same conditions as the above red ink, according to the composition shown in Table 10, the viscosity value by an L-type viscometer (25 ° C) is 35 to 45 Pa · s. The active energy ray-curable red inks 1 to 3 of Examples 41 to 42 and Comparative Example 24 were obtained.

  About the ink of Examples 41-42 and the comparative example 24, sclerosis | hardenability, transferability, and odor were evaluated similarly to the said red ink. The results are shown in Table 11.

  From the data in Table 11, it is confirmed that the red inks of Examples 41 to 42 have the same curability as Comparative Example 24, which is a conventional example, are excellent in migration (low migration), and are suppressed in odor. It was done.

  According to the present invention, the LED-UV lamp has good curability, hardly migrates (low migration), and can be effectively used as an active energy ray-curable ink that can greatly reduce odor during curing. Even with a low-energy light source like this (even if the cumulative amount of UV irradiation is small), the curability is sufficient, which contributes to environmental conservation and can also suppress odors. Since the migration can be significantly suppressed and the elution of the photopolymerization initiator from the cured film itself is small, it can be effectively used as an active energy ray-curable ink for food packaging containers such as beverages.

1 Substrate 2 Cured film (Q)
3 Ink-receiving layer surface 4 Resin layer surface p1 Base material provided with cured film p2 Base material not provided with cured film

Claims (5)

An active energy ray-curable ink containing the following photopolymerization initiator (A) containing 6 to 25% by mass in an active energy ray-curable ink and a diallyl phthalate resin (B),
The active energy ray curable ink is 1.6 × on the surface of the ink receiving layer of the substrate (P) provided with a resin layer on one side of the base paper (X) and an ink receiving layer on the other side. Applying at 10 ⁻⁴ g / cm ² , and using a UV irradiation device, the UV irradiation is carried out under the condition that the UV irradiation integrated light quantity becomes 10 mJ / cm ² , and the cured film (Q) is cured. There is no odor from the film surface, and the cured film surface of the substrate (p1) provided with the cured film cut to an area of 600 cm ² and the substrate (p2) not provided with the cured film having the same area The resin layer surface was overlaid and allowed to stand for 48 hours in an environment of 25 ° C. and 50% RH at a load of 0.5 kg / cm ² , and then the substrate (p2) was placed in 1000 ml of 95% ethanol aqueous solution. After immersion for 24 hours in an environment of 50 ° C and 50% RH, in ethanol When the total concentration of existing photopolymerization initiator was determined, active energy ray-curable ink and less than 100 ppb.
Base paper (X): Milk carton paper, cardboard paper, coated cardboard paper, Manila cardboard paper, Kent paper, aluminum evaporated paper, synthetic paper (YUPO paper) with a thickness of 2 mm or less
Photopolymerization initiator (A): 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2-[(4-methylphenyl) methyl ] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 4 , 4′-bis (diethylamino) benzophenone The photopolymerization initiator (A) is 2-benzyl-2- (dimethylamino) -1- (4-morpholinophenyl) -1-butanone or 2- (dimethylamino) -2-[(4-methylphenyl) One or more (a1) selected from methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone and 4,4′-bis (diethylamino) benzophenone (a2),
2. The active energy ray-curable ink according to claim 1, wherein (a1) :( a2) is 1: 0.2 to 3 by weight. The diallyl phthalate resin (B) is an orthotype (b1) and an isotype (b2),
The active energy ray-curable ink according to claim 1 or 2, wherein (b1) :( b2) is 5:95 to 95: 5 by weight.   Printed matter obtained by using the active energy ray-curable ink according to any one of claims 1 to 3.   A food packaging container formed using the printed matter according to claim 4.

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