WO2015141552A1

WO2015141552A1 - Active energy ray-curable offset ink composition

Info

Publication number: WO2015141552A1
Application number: PCT/JP2015/057280
Authority: WO
Inventors: 誓山本; 圭佑若原; 梓余語; 育男松尾
Original assignee: Ｄｉｃグラフィックス株式会社
Priority date: 2014-03-18
Filing date: 2015-03-12
Publication date: 2015-09-24
Also published as: JPWO2015141552A1; JP5815913B1

Abstract

　The present invention addresses the problem of providing an active energy ray-curable offset ink composition characterized by having excellent suitability for printing and good curing properties and film flexibility even under low-energy ultraviolet irradiation, and a printed article using the same. An active energy ray-curable offset ink composition characterized by containing a photopolymerization initiator composition, (A) a polymerizable urethane acrylate compound obtained by reacting a polyfunctional acrylate having a hydroxyl group and a diisocyanate compound having a weight-average molecular weight in the range of 140-300 and having an aromatic structure or an alicyclic structure as 5-60 wt% of the total amount thereof, and (B) a polymerizable acrylate monomer other than the aforementioned polymerizable urethane acrylate compound.

Description

Active energy ray-curable offset ink composition

The present invention relates to an active energy ray-curable offset ink composition characterized by maintaining excellent curability, flexibility after film curing, and excellent printability for package ink printing applications such as paper containers. Furthermore, the present invention relates to a printed matter using the composition.

∙ Ultraviolet (UV) curable offset ink that cures under active energy ray conditions is widely used in the field of package printing for food packaging such as toys and paper containers due to the convenience of instantaneous drying characteristics.

On the other hand, in active energy ray curable offset printing, excellent ink film curing performance is required from the viewpoint of productivity, so even a small amount of active energy ray irradiation can be cured as a raw material for offset ink used in this. For example, it is necessary to use a polyfunctional monomer having four or more functionalities.

Specific examples of these polyfunctional monomers include ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate (tetrafunctional), dipentaerythritol pentaacrylate (pentafunctional), and dipentaerythritol hexaacrylate (hexafunctional). A pentafunctional or higher functional acrylate monomer is particularly excellent in curability and is widely used mainly for package printing (for example, see Patent Document 1).

Further, if these polyfunctional acrylates such as pentafunctional and hexafunctional are used, the curability is excellent, but the flexibility of the film after curing is not sufficient. For example, in package printing, in the cutting process after printing, the ink in the cut part There was a problem that the cured film peeled off, and cracks (cracking of the ink cured film) occurred in the folded portion of the printed matter in the box making process.

JP 2010-742 A

An object of the present invention is to provide an active energy ray-curable offset ink composition characterized by having good active energy ray curability, film flexibility and excellent printability, and a printed matter thereof.

The present inventors have found that the above-mentioned problems can be achieved by appropriately employing a urethane acrylate having a specific structure excellent in reaction curability and flexibility of a cured film and a low-viscosity monomer, and to complete the present invention. It came.

That is, the present invention reacts a polyisocyanate having a hydroxyl group with a diisocyanate compound having an aromatic ring structure or an alicyclic structure having a weight average molecular weight of 140 to 300, which is 5 to 60% by weight of the total amount. The present invention relates to an active energy ray-curable offset ink composition comprising a polymerizable urethane acrylate compound (A) and a polymerizable acrylate monomer (B) other than those described above.

Furthermore, the present invention relates to an active energy ray-curable offset ink composition having one hydroxyl group in the molecule of the polyfunctional acrylate having a hydroxyl group and having 3 to 5 acryloyl groups.

Furthermore, the present invention provides the polymerizable urethane acrylate compound (A) having a weight average molecular weight in the range of 500 to less than 3,000 and a viscosity of less than 200,000 millipascal seconds (mPa · s) at 25 ° C. The present invention relates to an active energy ray-curable offset ink composition.

Furthermore, the present invention relates to an active energy ray-curable offset ink composition in which the diisocyanate compound is toluene diisocyanate.

Furthermore, the present invention relates to an active energy ray-curable offset ink composition in which the polyfunctional acrylate having a hydroxyl group is pentaerythritol triacrylate.

Furthermore, the present invention relates to an active energy ray-curable offset ink composition in which the polymerizable acrylate monomer (B) other than the above is ethylene oxide-modified trimethylolpropane triacrylate.

Furthermore, the present invention also provides a printed matter that is offset printed using the active energy ray-curable offset ink composition.

According to the present invention, an active energy ray-curable offset ink composition having good curability, film flexibility, and excellent printability can be provided.

The active energy ray-curable offset ink composition of the present invention comprises a diisocyanate compound having an aromatic ring structure or an alicyclic structure having a weight average molecular weight of 140 to 300 and a hydroxyl group, which is 5 to 60% by weight of the total amount. By containing the polymerizable urethane acrylate compound (A) obtained by reacting the polyfunctional acrylate having the polymerizable acrylate monomer and the polymerizable acrylate monomer (B) other than those described above, the intended effect of the present invention is achieved.

The active energy ray-curable offset ink composition of the present invention can be formed into a cured film by irradiating active energy rays after printing on a substrate. Examples of the active energy rays include ionizing radiation such as ultraviolet rays, electron beams, α rays, β rays, and γ rays. Of these, ultraviolet (UV) is particularly preferred from the viewpoint of curability and convenience.

As described above, the active energy rays for curing the active energy ray-curable offset ink composition of the present invention are ionizing radiations such as ultraviolet rays, electron beams, α rays, β rays, and γ rays. Examples of energy sources or curing devices include germicidal lamps, ultraviolet fluorescent lamps, ultraviolet light emitting diodes (UV-LEDs), carbon arcs, xenon lamps, high pressure mercury lamps for copying, medium or high pressure mercury lamps, ultrahigh pressure mercury lamps, and no electrodes Examples thereof include lamps, metal halide lamps, ultraviolet rays using natural light as a light source, or electron beams using a scanning type or curtain type electron beam accelerator.

When ultraviolet rays are used as an active energy ray for curing the active energy ray-curable offset ink composition of the present invention, a publicly known and publicly known photopolymerization initiator composition can be used as an ink curing agent. A cleavage type photoinitiator and a hydrogen abstraction type photoinitiator are mentioned. Examples of the intramolecular cleavage type photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy. -2-Methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl-phenylketone, 2-hydroxy-1- {4- [4 -(2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,2- Acetophenone compounds such as diethoxy-1,2-diphenylethane-1-one; 1- [4- (phenylthio)-, 2- O-benzoyloxime)], 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime), 3,6 A carbazole compound such as bis (2-methyl-2-morpholinopropanonyl) -9-butylcarbazole, a benzoin compound such as benzoin, benzoin methyl ether, and benzoin isopropyl ether;

2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2- (dimethylamino) -2- (4-methylbenzyl) -1- (4-morpholinophenyl) butane Aminoalkylphenones such as -1-one, 2-methyl-2-morpholino ((4-methylthio) phenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone Compounds: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl -Acylphosphine oxide compounds such as pentylphosphine oxide; benzyl, methylphenyl Li oxy esters.

On the other hand, examples of the hydrogen abstraction type photopolymerization initiator include benzophenone, methyl 4-phenylbenzophenone o-benzoylbenzoate, 4,4′-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide. Benzophenone compounds such as acrylated benzophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 3,3′-dimethyl-4-methoxybenzophenone; 2-isopropylthioxanthone, 2,4 Thioxanthone compounds such as dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone; amino such as 4,4′-bisdimethylaminobenzophenone and 4,4′-bisdiethylaminobenzophenone Benzophenone-based compounds; Other 10-butyl-2-chloro acridone, 2-ethyl anthraquinone, 9,10-phenanthrenequinone, camphorquinone, and the like. These photopolymerization initiators can be used alone or in combination of two or more. Of these, aminoalkylphenone compounds are preferable because they are particularly excellent in curability. In particular, an ultraviolet light emitting diode (UV-LED) light source that generates ultraviolet light having an emission peak wavelength in the range of 350 to 420 nm is used as an active energy ray source. When used as, it is preferable from the viewpoint of excellent curability that an aminoalkylphenone compound, an acylphosphine oxide compound, and an aminobenzophenone compound are used in combination.

The amount of these photopolymerization initiator compositions used is in the range of 1 to 20% by weight as the total amount used with respect to 100% by weight of the non-volatile components in the active energy ray-curable offset ink composition of the present invention. It is preferable. That is, when the total amount of the polymerization initiator used is 1% by weight or more, good curability can be obtained, and when it is 20% by weight or less, an unreacted polymerization initiator remains in the cured product. The problem of physical properties such as migration, solvent resistance, weather resistance and the like can be avoided. From the point that these performance balances become better, in particular, the total use amount is 3 to 15% by weight with respect to 100% by weight of the nonvolatile components in the active energy ray-curable ink composition of the present invention. It is more preferable that However, when an electron beam is used as the active energy ray, the use of these photopolymerization initiators is not essential in principle.

Further, in addition to the above-described polymerization initiator, it is possible to further improve curability by using a photosensitizer. Such photosensitizers include, for example, amine compounds such as aliphatic amines, ureas such as o-tolylthiourea, sulfur compounds such as sodium diethyldithiophosphate, s-benzylisothiouronium-p-toluenesulfonate, and the like. It is done. The use amount of these photosensitizers is 1 as the total use amount with respect to 100% by weight of the non-volatile component in the active energy ray-curable ink composition of the present invention from the viewpoint that the effect of improving curability is good. It is preferably in the range of ˜20% by weight.

As an essential component of the active energy ray-curable offset ink composition of the present invention, diisocyanate having an aromatic ring structure or an alicyclic structure that is 5 to 60% by weight of the total amount of the composition and having a weight average molecular weight of 140 to 300 Examples thereof include a polymerizable urethane acrylate compound (A) obtained by reacting a narate compound with a polyfunctional acrylate having a hydroxyl group.
The content of the polymerizable urethane acrylate compound (A) is preferably in the range of 5 to 60% by weight of the total amount of the composition, and if it is less than 5% by weight, good curability cannot be obtained. Exceeding% by weight is not preferable because it becomes difficult to keep the viscosity of the offset ink within an appropriate range. The diisocyanate compound which is a constituent component of the polymerizable urethane acrylate compound (A) preferably has an aromatic ring structure or an alicyclic structure for the purpose of obtaining good curability.

The weight average molecular weight of the diisocyanate compound having an aromatic ring structure or alicyclic structure is preferably in the range of 140 to 300. When a diisocyanate compound having a molecular weight exceeding 300 is used, it is not preferable because the curability of the polymerizable urethane acrylate compound is lowered. Examples of the diisocyanate compound having an aromatic ring structure and constituting the polymerizable urethane acrylate compound (A) having a weight average molecular weight in the range of 140 to 300 include 2,4-toluene diisocyanate and 2,6-toluene. Diisocyanate, 3,4-toluene diisocyanate (all weight average molecular weight: 174), 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate (all weight average molecular weight: 250) 1,3-xylylene diisocyanate (weight average molecular weight: 188).

The number of hydroxyl groups in the molecule of the polyfunctional acrylate having a hydroxyl group is preferably 1, and the number of acryloyl groups is preferably in the range of 3-5. When the number of hydroxyl groups is 2 or more, there is a tendency that acrylate becomes a crosslinking component, resulting in an increase in viscosity, a decrease in reactivity, and gelation due to excessive increase in molecular weight. In addition, the residual amount of unreacted hydroxyl groups There is a tendency to increase the offset printing suitability. When the number of acryloyl groups is 2 or less, the curability is lowered, and when it is 6 or more, the flexibility of the ink cured film tends to be impaired.

Furthermore, examples of the diisocyanate compound having an alicyclic structure and constituting a polymerizable urethane acrylate compound (A) obtained by reacting the polyfunctional acrylate having a hydroxyl group and having a weight average molecular weight of 140 to 300 include isophorone. Examples include diisocyanate (weight average molecular weight: 222), 1,4-cyclohexylene diisocyanate (weight average molecular weight: 166), 4,4′-methylenebiscyclohexyl diisocyanate (weight average molecular weight: 262), and the like. . On the other hand, when an aliphatic diisocyanate compound such as hexamethylene diisocyanate (weight average molecular weight: 168) or 2,2,4-trimethylhexamethylene diisocyanate (weight average molecular weight: 210) is used, polymerization is performed. This is not preferable because the cured film of the curable urethane acrylate compound becomes too flexible and the curability is lowered.

Among the diisocyanate compounds having an aromatic ring structure or an alicyclic structure and having a molecular weight in the range of 140 to 300, an aromatic ring structure is more preferable, and 2,4-toluene diisocyanate and 2,6-toluene diisocyanate are preferred. (Both weight average molecular weights: 174) are particularly preferred.

The polymerizable urethane acrylate compound (A) can be obtained by urethanating the diisocyanate compound and a polyfunctional acrylate having a hydroxyl group. Examples of the polyfunctional acrylate having a hydroxyl group include 2-hydroxyethyl acrylate, 2 -Hydroxypropyl acrylate, 2-hydroxybutyl acrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and compounds obtained by addition polymerization of these ethylene oxide, propylene oxide, tetrahydrofuran or ε-caprolactone, etc. Pentaerythritol triacrylate, which is an acrylate, and pentafunctional dipentaerythritol pentaacrylate are preferred. Pentaerythritol Li acrylate is particularly preferred.

The polymerizable urethane acrylate compound (A) preferably has a weight average molecular weight in the range of 500 or more and less than 3,000, and a viscosity of less than 200,000 millipascal seconds (mPa · s) at 25 ° C., The weight average molecular weight is particularly preferably in the range of 700 or more and less than 1,400. When the molecular weight is 3,000 or more, it is difficult to obtain good curability under the active energy ray irradiation conditions for offset printing because the kinetic performance of the molecule is lowered, and when the viscosity is 200,000 millipascal seconds or more. It is difficult to keep the viscosity of the offset ink composition within a suitable range.

The polymerizable urethane acrylate compound (A) can be obtained by urethanation reaction of the diisocyanate compound and the polyfunctional acrylate having a hydroxyl group. Specifically, both are mixed for 5 hours at 90 ° C. It can be obtained by reacting to some extent. For the purpose of obtaining excellent curability and offset printing suitability, it is preferable that the isocyanate group is urethanated with a hydroxyl group as much as possible. For example, the ratio of the unreacted isocyanate group is preferably less than 10%.

The polymerizable urethane acrylate compound (A) can be blended with a thermal polymerization inhibitor in order to prevent thermal polymerization during synthesis and maintain storage stability. Examples of typical thermal polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, p-benzoquinone, 2,5-t-butylhydroquinone, phenothiazine, N-nitrosophenylhydroxylamine aluminum salt, diethyl Examples include copper dithiocarbamate and 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl. The blending amount is preferably in the range of 0.01 to 1% by weight with respect to the urethane acrylate compound (A).

As a specific example of the polymerizable urethane acrylate compound (A) that is an essential component of the active energy ray-curable offset ink composition of the present invention, one molecule of 2,4-toluene diisocyanate and two molecules of pentaerythritol triacrylate are reacted. The chemical structure of the resulting compound is shown in Formula (1), and the chemical structure of the compound obtained by reacting one molecule of 4,4′-diphenylmethane diisocyanate with two molecules of pentaerythritol triacrylate is shown in Formula (2).

As a means for improving the curability of the active energy ray-curable offset ink composition of the present invention, it is effective to increase the concentration of polymer groups (acrylic groups) in the composition. Although it is effective to use, for example, dipentaerythritol pentaacrylate (DPPA) or dipentaerythritol hexaacrylate (DPHA) having a high density of two polymer groups, the intermolecular distance is reduced when the polymer groups react and bond with each other. As a result, the ink cured film is in a tightly contracted state and the flexibility tends to be impaired. On the other hand, the polymerizable urethane acrylate compound (A) described in the present invention has a plurality of polymer groups in the molecule, while having both a flexible urethane bond and a strong aromatic skeleton or alicyclic skeleton. It is presumed that the balance between flexibility and flexibility is excellent. Furthermore, by using together with a low-viscosity monomer, the compounding concentration of the urethane acrylate compound (A) in the ink composition can be increased, and the curing performance can be further effectively improved.

Examples of the polymerizable acrylate monomer (B) other than the polymerizable urethane acrylate compound (A) used in the active energy ray-curable offset ink composition of the present invention include publicly known acrylate monomers, such as monofunctional acrylates. Examples of the monomer include ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, lauryl acrylate, tridecyl acrylate, hexadecyl acrylate, octadecyl acrylate, isoamyl acrylate, isodecyl acrylate, isostearyl acrylate, cyclohexyl acrylate, benzyl acrylate , Methoxyethyl acrylate, butoxyethyl acrylate, phenoxyethyl acrylate, phenoxydie Lenglycol acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 3-chloro-2-hydroxypropyl acrylate, diethylaminoethyl acrylate, nonylphenoxyethyl tetrahydro Examples include furfuryl acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, isobornyl acrylate, dicyclopentanyl acrylate, and dicyclopentenyloxyethyl acrylate.

Examples of the bifunctional or higher acrylate monomer include 1,4-butanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, 2 -Methyl-1,8-octanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, tricyclodecane dimethanol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, Dihydric alcohol diacrylates such as dipropylene glycol diacrylate and tripropylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol A trivalent or more polyvalent polyacrylate such as acrylate, tris (2-hydroxyethyl) isocyanurate diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol polyacrylate Diacrylate of a diol obtained by adding 2 mol or more of ethylene oxide or propylene oxide to 1 mol of polyhydric alcohol, 1 mol of neopentyl glycol, obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of glycerin Triol triacrylate, 3 moles of ethylene oxide or propylene oxide per mole of trimethylolpropane It added to triol di- or tri-acrylates obtained, polyacrylate polyoxyalkylene polyols and di acrylate of a diol obtained by adding 2 moles or more of ethylene oxide or propylene oxide to bisphenol A1 molar and the like.

However, in the present invention, for the purpose of obtaining suitable curability, flexibility, offset printing suitability, and printing press rubber roller suitability by combining with the polymerizable urethane acrylate compound (A), the polymerizable acrylate monomer (B) is in the molecule. The number of acryloyl groups in the polymer is 2 or more, it is hydrophobic, the weight average molecular weight is in the range of 200 to 600, and the viscosity at 25 ° C. is 1 millipascal second or more to less than 150 millipascal second (mPa · s). As specific examples satisfying these requirements, EO3TMPTA (ethylene oxide average 3 mol-modified trimethylolpropane triacrylate, viscosity 50 to 70 mPa · s, weight average molecular weight 428), DPGDA (dipropylene glycol diacrylate, viscosity 5 to 30 mPa · s, weight flat Molecular weight 240), HDDA (hexanediol diacrylate, viscosity 5-15 mPa · s, weight average molecular weight 226), TMPTA (trimethylolpropane triacrylate, viscosity 80-120 mPa · s, weight average molecular weight 296), GPTA (propylene oxide average) 3 mol-modified glycerin triacrylate, viscosity 80 to 120 mPa · s, weight average molecular weight 428), PO3TMPTA (propylene oxide average 3 mol modified trimethylolpropane triacrylate, viscosity 70 to 100 mPa · s, weight average molecular weight 470) and the like. However, among these, ethylene oxide-modified trimethylolpropane triacrylate having a weight average molecular weight in the range of 300 to 600 has low viscosity and excellent curability, and also has good offset printing suitability. In preferred that points at. These polymerizable acrylate monomers (B) may be used alone or in combination of any one or more thereof.

In the active energy curable offset ink composition of the present invention, a wax can be added for the purpose of improving curability. Examples of the wax include paraffin wax, carnauba wax, beeswax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, polytetrafluoroethylene wax, amide wax and the like, and C8-C18 grades such as coconut oil fatty acid and soybean oil fatty acid. The fatty acid etc. which are in the range can be mentioned. Among them, powder type or particle type polyolefin waxes typified by polyethylene wax and oxidized polyethylene wax are preferable because good ink fluidity and curability are obtained, and the melting point of the polyolefin wax is in the range of 90 to 130 ° C. A polyolefin wax having an average particle diameter D50 in the range of 1 to 10 micrometers is more preferable. When the average particle diameter D50 is less than 1 micrometer, it is difficult to improve the curability, and when it exceeds 10 micrometers, the ink transfer property on the printing press is remarkably deteriorated and the offset printability is impaired. The total amount of wax used is preferably in the range of 0.1 to 5% by weight with respect to 100% by weight of the non-volatile component in the active energy ray-curable composition of the present invention.

In addition, as the measuring method of the average particle diameter, it was calculated from the situation of the frequency distribution measured with Hitachi, Ltd. operation type electron microscope S-3400N.

Examples of the pigment used in the active energy ray-curable offset ink composition of the present invention include publicly known organic pigments for coloring, such as “Organic Pigment Handbook (Author: Isao Hashimoto, Publisher: Color Office, Organic pigments for printing inks, etc., which are listed in the first edition of 2006), soluble azo pigments, insoluble azo pigments, condensed azo pigments, metal phthalocyanine pigments, metal-free phthalocyanine pigments, quinacridone pigments, perylene pigments, perinone pigments, Indolinone pigments, isoindoline pigments, dioxazine pigments, thioindigo pigments, anthraquinone pigments, quinophthalone pigments, metal complex pigments, diketopyrrolopyrrole pigments, carbon black pigments, and other polycyclic pigments can be used.

In the active energy ray-curable offset ink composition of the present invention, inorganic fine particles may be used as extender pigments. As inorganic fine particles, inorganic coloring pigments such as titanium oxide, kraftite, zinc white; lime carbonate powder, precipitated calcium carbonate, gypsum, clay (ChinaClay), silica powder, diatomaceous earth, talc, kaolin, alumina white, barium sulfate, Examples include inorganic extender pigments such as aluminum stearate, magnesium carbonate, barite powder, and abrasive powder; inorganic pigments such as wrinkles, silicone, and glass beads. By using these inorganic fine particles in the ink in the range of 0.1 to 20% by weight, it is possible to obtain effects such as ink fluidity adjustment, prevention of misting, and prevention of penetration into printing substrates such as paper. is there.

In the active energy curable offset ink composition of the present invention, various publicly known binder resins can be used. The binder resin described here refers to all resins having appropriate pigment affinity and dispersibility, and rheological properties required for printing inks. For example, non-reactive resins include diallyl phthalate resin and epoxy resin. Resin, polyurethane resin, polyester resin, petroleum resin, rosin ester resin, poly (meth) acrylic acid ester, cellulose derivative, vinyl chloride-vinyl acetate copolymer, polyamide resin, polyvinyl acetal resin, butadiene-acrylonitrile copolymer, etc. An epoxy acrylate compound, a urethane acrylate compound, a polyester acrylate compound, etc. having at least one polymerizable group in the resin molecule can also be used, and these binder resin compounds are used alone. Even one It may be used in combination with at least species.

In the active energy ray-curable offset ink composition of the present invention, as other blends of the above-described components, dyes, organic solvents, antistatic agents, antifoaming agents, viscosity modifiers, light-resistant stabilizers, weather-resistant stabilizers, Additives such as a heat stabilizer, an ultraviolet absorber, an antioxidant, a leveling agent, and a pigment dispersant can be used.

The printing substrate used in the active energy ray-curable offset ink composition of the present invention is not particularly limited. For example, catalogs, posters, flyers, CD jackets, direct mails, brochures, cosmetics and beverages, pharmaceuticals, toys, equipment, etc. Quality paper, coated paper, art paper, imitation paper, thin paper, cardboard, etc., various synthetic paper, polyester resin, acrylic resin, vinyl chloride resin, vinylidene chloride resin, polyvinyl alcohol, polyethylene, Polypropylene, polyacrylonitrile, ethylene vinyl acetate copolymer, ethylene vinyl alcohol copolymer, ethylene methacrylic acid copolymer, nylon or polylactic acid, polycarbonate film or sheet, cellophane, aluminum foil, and other conventional printing substrates It can be mentioned various substrates that are used Te.

The active energy ray-curable offset ink composition described in the present invention is produced in the same manner as the conventional active energy ray-curable offset ink composition purple, the color pigment, polymerizable acrylate monomer, binder resin, photopolymerization initiator, It is manufactured by blending a sensitizer and other additives, stirring and mixing with a mixer or the like, and kneading using a dispersing machine such as a three-roll mill or a bead mill.

Hereinafter, the present invention will be specifically described with reference to examples.

[Method for producing active energy ray-curable offset ink]
Various ink compositions were obtained by kneading the inks of Examples 1 to 3 and Comparative Examples 1 to 4 with a three roll mill according to the compositions of Tables 1 and 2. In addition, the numerical value of Table 1 and Table 2 is weight%. In addition, indigo pigment DIC Corporation FASTOGEN BLUE TGR-1 (Pigment Blue 15: 3, phthalocyanine blue) was used as a coloring component for all ink compositions.

[Manufacturing method of exhibition colors]
The active energy ray-curable ink composition thus obtained was used on a rubber roll and metal roll of the RI tester using a simple color developing machine (RI tester, manufactured by Toyoe Seiko Co., Ltd.) and using 0.10 ml of ink. With an indigo density of 1.6 (measured with a SpectroEye densitometer from X-Rite) over an area of 200 cm ^{2 on} the surface of coated cardboard (UF coat manufactured by Oji Materia Co., Ltd., 350 g / m ² ) The color was developed so as to be applied uniformly, and a color-extended product was produced. The RI tester is a test machine that develops ink on paper or film, and can adjust the amount of ink transferred and the printing pressure.

[Curing method using UV lamp light source]
Irradiation with ultraviolet rays (UV), which is an active energy ray, was performed on the color-extended product after the ink application to cure the ink film. Using a UV irradiation device equipped with a water-cooled metal halide lamp (output: 100 W / cm1 light) and a belt conveyor (made by Eye Graphics Co., Ltd., with a cold mirror), the color-exposed product is placed on the conveyor and directly under the lamp (irradiation distance: 11 cm) Was passed through at a speed of 100 meters per minute to cure the ink film. The amount of ultraviolet irradiation under each condition was measured using an ultraviolet integrating light meter (UNIMETER UIT-150-A / receiver UVD-C365 manufactured by USHIO INC.).

[Evaluation method 1-1 of active energy ray-curable ink composition 1-1: curability]
The curability was evaluated in the following three stages by checking the presence or absence of scratches on the surface of the developed product by the nail scratch method immediately after the ultraviolet irradiation. In the composition in which the ink cured film is scratched by rubbing with a nail, the printed material is easily damaged in each process such as cutting, box making and transportation of the printed material.
○: No scratches are generated in the nail scratch, and the curability is good.
(Triangle | delta): A slight crack generate | occur | produces with a nail | claw scratch and sclerosis | hardenability is moderate.
X: Scratches are generated in the nail scratches and the curability is poor.

[Evaluation method 1-2 of active energy ray-curable ink composition: solvent resistance]
The solvent resistance was evaluated by a solvent rubbing method. MEK (methyl ethyl ketone) was used as a solvent, and the surface of the developed product was rubbed back and forth 30 times immediately after UV irradiation in a state where MEK was sufficiently immersed in a cotton swab, and the presence or absence of scratches was confirmed and evaluated in the following three stages. In a composition in which scratches are generated on the ink-cured film, the printed material is easily damaged in each process such as cutting, box making, and transportation of the printed material. Moreover, when chemicals, detergents, beverages, or the like adhere to the ink-cured film for some reason, the printed matter is easily damaged.
○: No scratches are generated by solvent rubbing, and the solvent resistance is good.
Δ: Solvent rubbing causes slight scratches, and the solvent resistance is moderate.
X: Scratches are generated by solvent rubbing, and the solvent resistance is poor.

[Evaluation method 2 of active energy ray-curable ink composition: flexibility of cured film]
Using the UV lamp irradiation device, the color composition was irradiated with ultraviolet rays at a conveyor speed of 20 m / min to cure the ink composition. Thereafter, the color-extended product was bent at an angle of 180 ° with the ink cured film facing outward. By this evaluation method (180 ° bending test), a physical load is generated at the bent portion of the ink cured film, so that the flexibility was evaluated in the following three stages by observing cracks in the cured film after the test. .
○: The ink cured film does not crack and has good flexibility.
(Triangle | delta): The micro crack has generate | occur | produced in the ink cured film, and a softness | flexibility is medium.
X: A clear crack has occurred in the ink cured film, and the flexibility is poor.

[Offset printing method of active energy ray-curable ink composition]
With respect to the produced active energy ray-curable inks of Examples 1 to 3 and Comparative Examples 1 to 4, the offset printability was evaluated. 9000 sheets per hour using a Man Roland offset printing machine (Roland R700 printing machine, 40-inch wide machine) equipped with a water-cooled metal halide lamp (output: 160 W / cm, 3 lamps used) as an ultraviolet irradiation device. Offset printing was performed at a printing speed of. For the printing paper, OK Top Coat Plus (57.5 kg, A size) manufactured by Oji Paper Co., Ltd. was used. The fountain solution supplied to the printing plate was an aqueous solution obtained by mixing 98% by weight of tap water and 2% by weight of an etchant (FST-700, manufactured by DIC).

[Evaluation method 3 of active energy ray-curable ink composition: suitability for offset printing]
As an evaluation method of offset ink printing suitability, first set the water supply dial of the printing press to 40 (standard water amount), and the printed product density is standard process indigo density 1.6 (measured with a SpectroEye densitometer manufactured by X-Rite). The ink supply key was operated so that the ink supply key was fixed when the density was stabilized. Thereafter, 300 sheets were printed under the condition that the water supply dial was changed from 40 to 55 and the water supply amount was increased with the ink supply key fixed, and the indigo density of the printed material after 300 sheets was measured. Even when the amount of water supply is increased, the smaller the decrease in the density of the printed matter, the better the emulsification suitability and the better the printability. The printability of the active energy ray-curable ink was evaluated according to the following criteria.
A: The indigo density of the printed material is 1.5 or more, and the offset printability is good.
Δ: The indigo density of the printed material is 1.4 or more and less than 1.5, and the offset printability is moderate.
X: The indigo density of the printed material is less than 1.4, and the offset printability is poor.

(Measurement of weight average molecular weight)
In addition, the measurement of the weight average molecular weight (polystyrene conversion) by GPC in this invention was performed on condition of the following using the Tosoh Corp. HLC8220 system.
Separation column: 4 TSKgelGMHHR-N manufactured by Tosoh Corporation are used. Column temperature: 40 ° C. Moving layer: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml / min. Sample concentration: 1.0% by weight. Sample injection volume: 100 microliters. Detector: differential refractometer.

The numerical values in Tables 1 and 2 are% by weight.
TGR-1: FASTOGEN BLUE TGR-1, phthalocyanine blue (copper phthalocyanine) indigo pigment, manufactured by DIC ・ High filler # 5000PJ: talc with hydrous magnesium silicate, manufactured by Matsumura Sangyo Co., Ltd. ・ Magnesium carbonate TT: basic magnesium carbonate, SAI-381-N1: Polyolefin wax, Shamrock Co., diallyl phthalate resin varnish: 35% diallyl phthalate resin (Daiso Dup A, Daiso Co.) by weight and MIRAMER M410 (ditrimethylolpropane) Mixture of tetraacrylate (DTMPTA), viscosity 450-750 mPa · s, weight average molecular weight 467, manufactured by MIWON) 65% urethane acrylate 1: 2,4-toluene diisocyanate (TDI) and pentae Reaction product of thritol triacrylate; urethanation reaction of 2 moles of pentaerythritol triacrylate per 1 mole of TDI. Reaction product of urethane acrylate 2: 4,4'-diphenylmethane diisocyanate (MDI) and pentaerythritol triacrylate; MDI1 Urethane reaction of 2 moles of pentaerythritol triacrylate per mole ・ Urethane acrylate 3: Reaction product of hexamethylene diisocyanate (HDI) and pentaerythritol triacrylate; Urethane reaction of 2 moles of pentaerythritol triacrylate per mole of MDI ・ MIRAMER M600: Dipentaerythritol hexaacrylate (DPHA), viscosity 4000 to 7000 mPa · s, weight average molecular weight 578, manufactured by MIWON PETA-K: pentaerythritol tetraacrylate (PETA), viscosity 800 mPa · s, weight average molecular weight 352, manufactured by Daicel Ornex ・ MIRAMER M410: ditrimethylolpropane tetraacrylate (DTMPTA), viscosity 450 to 750 mPa · s, weight average Molecular weight 467, manufactured by MIWON, MIRAMER M3130: ethylene oxide (average 3 mol addition) modified trimethylolpropane triacrylate (EO3TMPTA), viscosity 50 to 70 mPa · s, weight average molecular weight 428, manufactured by MIWON Irgacure 907: 2-methyl- 1- [4- (methylthio) phenyl] -2-monoforinopropan-1-one, manufactured by BASF, EAB-SS: 4,4′-bis (diethylamino) benzophenone, The Chemical Industry Co., Ltd. - steerer TBH: 2-tert- butyl hydroquinone, manufactured by Seiko Chemical Co., Ltd.

In the ultraviolet curable offset ink composition described in the examples, good curability, flexibility to overcome the crack of the cured film when the substrate was folded, and good printability were obtained.

In the results of the comparative examples, it was not possible to cover all of curability, flexibility to overcome cracks in the cured film, and printability.

Claims

A polymerizable urethane acrylate compound obtained by reacting a polyisocyanate having a hydroxyl group with a diisocyanate compound having an aromatic ring structure or an alicyclic structure and having a weight average molecular weight of 140 to 300 which is 5 to 60% by weight of the total amount An active energy ray-curable offset ink composition comprising (A) and a polymerizable acrylate monomer (B) other than the above.
2. The active energy ray-curable offset ink composition according to claim 1, wherein the polyfunctional acrylate having a hydroxyl group has one hydroxyl group in the molecule and a acryloyl group number in the range of 3 to 5.
The weight average molecular weight of the polymerizable urethane acrylate compound (A) is in the range of 500 to less than 3,000, and the viscosity is less than 200,000 millipascal seconds (mPa · s) at 25 ° C. 2. The active energy ray-curable offset ink composition according to 2.
The active energy ray-curable offset ink composition according to any one of claims 1 to 3, wherein the diisocyanate compound is toluene diisocyanate.
The active energy ray-curable offset ink composition according to any one of claims 1 to 4, wherein the polyfunctional acrylate having a hydroxyl group is pentaerythritol triacrylate.
The polymerizable acrylate monomer (B) other than the above is an ethylene oxide-modified trimethylolpropane triacrylate having a weight average molecular weight of 300 to 600, and is contained in an amount of 1 to 40% by weight based on the total amount. 5. The active energy ray-curable offset ink composition according to any one of 5 above.
A printed matter offset-printed on the substrate using the active energy ray-curable offset ink composition according to any one of claims 1 to 6.