JP2010189609A - Active energy ray-curable ink composition for gravure printing, and printed matter printed using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active energy ray-curable ink composition for gravure printing that has excellent surface curability by an active energy ray-curing, does not cause set-off and blocking due to high speed printing, and can be dissolved or dispersed in an alkali aqueous solution in a wiping process, and to provide the printed matter printed using the ink composition. <P>SOLUTION: This active energy ray-curable ink composition for gravure printing includes, as essential components, a carboxyl group-containing acrylate oligomer having an acid value of 50-300 mg-KOH/g, a photopolymerizable acrylate monomer, a pigment, and a photoinitiator. The active energy ray-curable ink composition for gravure printing includes, based on the total amount, 10-30% of the carboxyl group-containing acrylate oligomer having the acid value of 50-300 mg-KOH/g, 20-50% of the photopolymerizable acrylate monomer, and 1-10% of the photoinitiator having absorption within long wavelength ultraviolet rays of 320-400 nm. The printed matter printed using the ink composition is also disclosed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the intaglio printing, the ink composition is excellent in dissolution of the alkaline aqueous wiping solution in the wiping step, can remove excess ink on the intaglio, and has excellent curability by active energy rays and excellent blocking resistance. Provide the printed matter.

  Intaglio prints have a unique feel and are characterized by fine and sharp lines, which cannot be realized without using a special printing press. It is widely used for printing cash vouchers such as government bonds, stock certificates, and gift certificates.

  The printing operation by the intaglio printing machine is a wiping roll that transfers ink to the intaglio surface on the intaglio cylinder by an inking device, and rotates the ink attached to the portions other than the pattern portion of the transferred ink in contact with the intaglio surface. After wiping, printing is performed by transferring the ink of the remaining pattern portion onto the paper passing between the intaglio cylinder and the impression cylinder.

  The wiping process with the wiping roll is immersed and rotated in a cleaning liquid such as trichlene placed in the liquid tank, and a cleaning member extending in the longitudinal direction of the roll contacts the circumferential surface of the wiping roll in the liquid tank. The ink transferred to the wiping roll by wiping is removed by the cleaning action of the cleaning member and the cleaning liquid, dissolved in the cleaning liquid, and continuously wiped.

  In the wiping process with the wiping roll, wiping can be continuously performed by dispersing or dissolving the wiped ink in an oily solution or an aqueous solution containing a surfactant. The case of using an oily solution is called oily wiping, and the case of using an aqueous solution is called aqueous wiping. However, because of the low load on the work environment, water wiping can be used as an alkaline aqueous solution by dissolving sodium carbonate in water. The method is used.

  In general, photopolymerizable acrylate monomers used in UV curable inks for offset printing have poor solubility in aqueous solutions, and the wiping process during printing is insufficient, resulting in smudges on printed matter. Therefore, it is not suitable for the aqueous wiping method.

  On the other hand, ink that is dried by irradiation with ultraviolet rays is frequently used for reasons such as an increase in printing speed and weather resistance of printed matter. However, in the case of an ink in which a pigment that absorbs ultraviolet rays is dispersed, the thickness of the curable ink film is limited to several μm, and in the case of intaglio printing, the thickness of the ink film is several tens of μm. As a result, it is difficult to use commonly used ultraviolet curable inks.

  Therefore, an ink having both UV curing and oxidative polymerization functions for preventing the set-off by curing the surface by ultraviolet irradiation and gradually curing the uncured portion inside the ink by oxidative polymerization, and printed matter using the same are disclosed. ing. (Patent Document 1)

  In addition, as an ink composition that can remove excess ink with an aqueous wiping solution during intaglio printing and has flexibility in the ink film, acrylic acid ester obtained by dehydration condensation of polyglycerin and acrylic acid, and glycidyl ether of polyglycerin It is disclosed that an ink composition obtained by using an ultraviolet curable material and an oxidative polymerizable material containing at least one of epoxy acrylates obtained by adding acrylic acid, and a printed material thereof are obtained. (Patent Document 2)

  However, in the ink composition having both UV curing and oxidative polymerization functions, since the drying to the inside is not complete immediately after printing, the set-off and the friction resistance cannot be sufficiently satisfied. Since the removal of excess ink is not complete, no solution has been reached.

Japanese Patent Publication No. 8-892 JP 2002-38065 A

  The present invention has excellent surface curability due to active energy ray curing, excellent friction resistance, no occurrence of set-off caused by high-speed printing, and when wiping off excess ink, from the problem of working environment An object of the present invention is to provide an active energy ray-curable ink composition for intaglio printing that can be dissolved or dispersed in an alkaline aqueous solution without using an oil-based wiping method, and a printed product thereof.

  The present invention comprises a carboxyl group-containing acrylate oligomer having an acid value of 50 to 300 mgKOH / g, a photopolymerizable acrylate monomer excluding the carboxyl group-containing acrylate oligomer, a photoinitiator, and an active energy for intaglio printing, The present invention relates to a linear curable ink composition.

  Furthermore, the present invention relates to the active energy ray-curable ink composition for intaglio printing, wherein the carboxyl group-containing acrylate oligomer has a cyclic structure in the molecule.

The present invention also relates to the above-mentioned active energy ray-curable ink composition for intaglio printing, wherein the pigment contains an extender pigment.
Furthermore, the present invention relates to the active energy ray-curable ink composition for intaglio printing, wherein the photoinitiator has an absorption wavelength of 320 to 400 nm.
Moreover, this invention relates to the printed matter characterized by printing the said active energy ray hardening-type ink composition for intaglio printing on a base material.

  According to the present invention, an active energy ray-curable ink having excellent surface curability by ultraviolet curing, excellent friction resistance, and capable of being dissolved or dispersed in water or an alkaline aqueous solution when wiping off excess ink. It has become possible to provide a composition and its printed matter.

  That is, by using an acrylate oligomer containing a carboxyl group having an acid value of 50 to 300 mgKOH / g, good solubility can be obtained by a neutralization reaction between an acid and an alkali.

  In addition, since there is an acrylate, even a thick film can have a three-dimensional crosslinked structure, and a sufficient cured film can be obtained.

Further, since the acrylate has a cyclic structure, rapid curing shrinkage during polymerization can be alleviated, and sufficient film strength can be obtained.
Moreover, by using a photoinitiator having absorption of long wavelength ultraviolet rays of 320 to 400 nm, sufficient internal curability can be ensured even when the ink film has a thickness of about 10 μm.

  The active energy rays used in the present invention are ultraviolet rays and electron beams, but are not necessarily limited thereto.

  The carboxyl group-containing acrylate having an acid value of 50 to 300 mgKOH / g used in the present invention is pentaerythritol triacrylate, dipentaerythritol pentaacrylate, EO-modified 1,6 hexanediol acrylate, ECH-modified phthalic acid diacrylate, stearic acid An acrylate obtained by adding an acid anhydride to an acrylate containing a hydroxyl group, such as modified pentaerythritol diacrylate, 2-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, and 2-hydroxypropyl acrylate.

  Acid components include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, hymic anhydride, maleic anhydride, trimellitic anhydride, methylcyclohexene One or more polybasic acids such as tricarboxylic acid anhydride and pyromellitic anhydride can be used.

The acid value used in the present invention is measured by JISK2501.
The acid value is preferably 50 to 300 mgKOH / g, and more preferably 70 to 120 mgKOH / g. If it is 50 mgKOH / g or less, sufficient solubility in an aqueous alkali solution cannot be ensured. Moreover, if it is 300 mgKOH / g or more, friction resistance cannot fully be ensured.

  The carboxyl group-containing acrylate oligomer having an acid value of 50 to 300 mgKOH / g used in the present invention has a cyclic structure in the molecule, such as a dicyclopentanyl ring, dicyclopentenyl ring, isobornene ring, morpholine ring, benzene ring, cyclohexane. Ring, cyclohexene ring, piperidine ring, naphthalene ring, piperazine ring, pyrimidine ring, furan ring, imidazole ring, imidazoline ring, imidazolidine ring, pyridine ring, picoline ring, quinazoline ring, anthracene ring or fluorene ring. It is not necessarily limited to this.

In the present invention, a non-reactive resin can be used in combination as appropriate.
Non-reactive resins include, for example, polyvinyl chloride, poly (meth) acrylic acid ester, epoxy resin, polyurethane resin, petroleum resin, cellulose derivatives (for example, ethyl cellulose, cellulose acetate, nitrocellulose), vinyl chloride-vinyl acetate copolymer Examples thereof include synthetic rubbers such as coalescence, polyamide resin, polyvinyl acetal resin, diallyl phthalate resin, and butadiene-acrylonitrile copolymer. These resins can be used alone or in combination of two or more thereof. In either case, a resin that is soluble in a photopolymerizable acrylate monomer having an ethylenically unsaturated double bond is used.

  In the present invention, the photopolymerizable acrylate monomer excluding the carboxyl group-containing acrylate oligomer having an acid value of 50 to 300 mgKOH / g refers to a monomer of monofunctional or polyfunctional (meth) acrylates, and ranges from 10 to 30% by weight. Used in

  Monofunctional monomers include alkyl (having 2 to 18 carbon atoms) (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl ( Examples thereof include benzyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, and tricyclodecane monomethylol (meth) acrylate.

  Polyfunctional (meth) acrylates include ethylene 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 glycol di (meth) acrylate, pentyl glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalyl hydroxypivalate di (meth) acrylate (commonly called manda), Hydroxypivalyl hydroxypivalate dicaprolactonate di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,8-octanediol (Meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,2-hexadecanediol di (meth) acrylate, 2-methyl-2,4-pentanediol di (meth) acrylate, bisphenol A tetraethylene oxide Adduct di (meth) acrylate, bisphenol F tetraethylene oxide adduct di (meth) acrylate, water-added bisphenol A tetraethylene oxide adduct di (meth) acrylate, water-added bisphenol F tetraethylene oxide adduct di (meth) acrylate , Water-added bisphenol A di (meth) acrylate, water-added bisphenol F di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylol prop N-tricaprolactonate tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolhexane tri (meth) acrylate, trimethyloloctanetri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra ( (Meth) acrylate, diglycerin tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, ditrimethylolpropane tetracaprolactonate, tetra (meth) acrylate, ditrimethylolethanetetra (meth) acrylate, ditrimethylolbutanetetra ( (Meth) acrylate, ditrimethylolhexanetetra (meth) acrylate, ditrimethyloloctanetetra (meth) acrylate, dipen Erythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, can be used tripentaerythritol hexa (meth) acrylate, tripentaerythritol hepta (meth) acrylate, a tripentaerythritol octa (meth) acrylate.

  Furthermore, there is an alkylene oxide adduct (meth) acrylate of an aliphatic alcohol compound as the acrylic monomer of the present invention. Examples of the alkylene oxide adduct (meth) acrylate monomer of an aliphatic alcohol compound include mono- or poly (1-20) alkylene (C2 to C20) oxide adducts (alkylene oxide) of an aliphatic alcohol compound. Carbon number as a monofunctional monomer 2-20 alkylene oxide adduct (meth) acrylate, for example, methanol mono- or poly (1-20) alkylene (C2-C20) oxide adduct (as alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide) (meth) Examples include acrylate, ethanol mono- or poly (1-20) alkylene (C2-C20) oxide adducts, etc. Further, ethylene glycol mono- or poly (1-20) alkyl as a bifunctional monomer. (C2-C20) oxide adducts (e.g., ethylene oxide, propylene oxide, butylene oxide) di (meth) acrylate, diethylene glycol mono- or poly (2-20) alkylene (C2-C20) oxide adducts and the like as alkylene oxides Furthermore, glycerin poly (2-20) alkylene (C2-C20) oxide adducts (eg, alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide) tri (meth) acrylate, trimethylolpropane poly (2 -20) Alkylene (C2-C20) oxide adducts and the like are exemplified, but not limited thereto.

  The poly (2-20) used in the present invention has a polymerization degree of an alkylene (C2-C20) oxide adduct.

  As a photoinitiator having absorption at 400 to 320 nm of long wavelength ultraviolet rays used in the present invention, Irgacure 369 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1- manufactured by Ciba Specialty Chemicals) Butanone), Esacure KIP100 (manufactured by Ramberty), Lucillin TPO (manufactured by BASF) and the like are exemplified, but not limited thereto.

Furthermore, it is preferable to use the following in combination as a photopolymerization initiator.
Examples of hydrogen abstraction type initiators include benzophenone, p-methylbenzophenone, p-chlorobenzophenone, tetrachlorobenzophenone, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, 2- Aryl ketone initiators such as isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4 diethylthioxanthone, 2,4 dichlorothioxanthone, acetophenone, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethyl) Amino) benzophenone, isoamyl p-dimethylaminobenzoate, dialkylaminoaryl ketone initiators such as p-dimethylaminoacetophenone, thioxanthone, xanthone Polycyclic carbonyl-based initiators such that halogen-substituted system is illustrated.

  Further, as a photocleavable initiator, benzoin such as benzoin, benzoin methyl ether, benzoin isopropyl ether, α-acrylobenzoin, benzyl, Irgacure 907 (2-methyl-2-morpholino (4-thiol produced by Ciba Specialty Chemicals) Methylphenyl) propan-1-one), Irgacure 651 (benzyl methyl ketal manufactured by Ciba Specialty Chemicals), Irgacure 184 (1-hydroxycyclohexyl phenyl ketone manufactured by Ciba Specialty Chemicals), Darocur 1173 (2-hydroxy-2-Merck) Methyl-1-phenylpropan-1-one), Darocur 1116 (Merck 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one), 4- (2- Roxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, ZLI3331 (4- (2-acryloyl-oxyethoxy) phenyl-2-hydroxy-2-propylketone, diethoxyacetophenone, BTTB (Ciba Specialty Chemicals) Nippon Oil & Fats Co., Ltd.), CGI 1700 (manufactured by Ciba Specialty Chemicals, etc.) are exemplified.

Moreover, a photoinitiator auxiliary agent can also be used in combination with a photoinitiator. As the photoinitiator aid, tertiary amines which are hydrogen donors are used. Specifically, aliphatic amines such as triethanolamine, methyldiethanolamine, triisopropanolamine, 4,4′-diethylaminobenzophenone, ethyl 2-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoate Aromatic amines such as isoamyl acid can be mentioned, and triethanolamine, methyldiethanolamine, dibutylethanolamine, triisopropanolamine, and 4,4′-diethylaminobenzophenone are preferable.
The photoinitiator is included in the composition at 1% to 10%, preferably 2 to 5%.

  Examples of the pigment used in the present invention include pigments intended for coloring inks and extender pigments.

  The extender pigment is made by pulverizing natural rock, clay, carbonated lime, precipitated calcium carbonate, gypsum, clay (China Clay), silica powder, diatomaceous earth, talc, alumina white, basic magnesium carbonate, Barite powder. In the present invention, it is used in order to reduce fluidity and prevent thin line characters from being printed. Calcium carbonate and silica are preferable, and the grain system is 0.001 to 0.20 μm as a BET specific surface area conversion value, more preferably 0.01 to 0.05 μm, and 10 to 100 m 2 / g as the BET specific surface area. Furthermore, 40-60 m <2> / g is good.

However, it is not limited to silica or calcium carbonate as long as it can be used to reduce fluidity so as not to crush the fine line characters of the printed matter which is the object of the present invention. For example, polyacrylic acid ester resin, polyurethane resin, polyester resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polysiloxane resin, phenol resin, epoxy resin, or these which are organic fine particles A copolymer, and the like.
The extender pigment is used in an ink composition of 10% to 40%, preferably 20% to 30%.

  Examples of the pigment used in the present invention include white pigments such as titanium oxide, yellow pigments such as mineral furnace yellow, navel yellow, naphthol yellow S, hansa yellow G, quinoline yellow lake, permanent yellow NCG, and tartrazine lake. Orange pigments such as Rembrilliant Orange RK, Pirazone Orange, Vulcan Orange, Benzidine Orange G, Indus Len Brilliant Orange GK, Permanent Red 4R, Lionol Red, Pyrarozone Red, Watching Lettuce Calcium Salt, Lake Red D, Brilliant Carmine 6B , Red pigments such as eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B, purple such as first violet B, methyl violet lake Paint, bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, indanthrene blue BC and other blue pigments, pigment green B, malachide green lake And green pigments such as FINA SWIRY GREEN G, and black pigments such as carbon black, acetylene black, lan black, and aniline black.

On the other hand, various additives for the purpose of anti-friction, anti-blocking, slip, anti-scratch and anti-dark reaction can be used as other additives in the composition. An inhibitor, a surfactant, an antifoaming agent, a polymerization inhibitor and the like may be added.
Examples of the composition of the active energy ray-curable ink for intaglio printing used in the present invention: Carboxyl group-containing acrylate oligomer having an acid value of 50 to 300 mgKOH / g or more 10 to 30% by weight
-Photopolymerizable acrylate monomer excluding acrylate oligomer containing carboxyl group having an acid value of 50 to 300 mgKOH / g or more 20 to 50% by weight
・ Photoinitiator 1-10% by weight
・ External pigments, organic pigments 10 to 40% by weight ・ Other additives 1 to 10% by weight
Etc. are mentioned as preferred compositions.

EXAMPLES The present invention will be specifically described as examples, but the present invention is not limited to the following examples. In the present invention,% indicates% by weight, part indicates part by weight, and the numbers in the table indicate% by weight.
An active energy ray-curable ink composition for intaglio was prepared according to the following formulation.

(Creation of ink composition)
Next, the carboxyl group-containing acrylate oligomer, the photopolymerizable acrylate monomer, the pigment, the photoinitiator, and other additives are mixed at a predetermined blending ratio using a butterfly mixer, and the maximum is achieved with three rolls. Each ink composition was prepared by dispersing the particle size to be 7.5 μm or less and preparing an ink composition with a spread meter so as to achieve a certain viscosity standard.

The carboxyl group-containing acrylate oligomer-1 is an acrylate oligomer (acid value 122) obtained by adding an acid anhydride to the hydroxyl group of pentaerythritol triacrylate, and the carboxyl group-containing acrylate oligomer-2 is a hydroxyl group of dipentaerythritol hexaacrylate. As an acrylate oligomer to which an acid anhydride is added (acid value 80) and a carboxyl group-containing acrylate oligomer-3, an acrylate oligomer having an acid anhydride added to the hydroxyl group of pentaerythritol triacrylate (acid value 200), an acid value of 50 As photopolymerized acrylate monomers excluding carboxyl group-containing acrylate oligomers of ~ 300 mgKOH / g, trimethylolpropane tetraethylene oxide addition triacrylate, photocleavable type Using the 1-hydroxycyclohexyl phenyl ketone as initiator. As the pigment, phthalocyanine blue, as the extender pigment-1, calcium carbonate (particle size: 0.04 μm), and as the extender pigment-2, silica (particle size: 0.016 μm) are used.

Here, the resin 1 is a reactive urethane acrylate oligomer purple light UV-7000B (manufactured by Nippon Synthetic Chemical Industry). The resin 2 is an epoxy resin. The resin 3 is a diallyl phthalate resin. The photopolymerizable acrylate monomer is trimethylolpropane tetraethylene. Oxide-added triacrylate, 1-hydroxycyclohexyl phenyl ketone is used as a photocleavable initiator, and phthalocyanine blue is used as a pigment.
The composition of wiping water is 5.0% sodium carbonate, 95.0% water, and PH is 11.

As a test for solubility in wiping water, the inks prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were diluted 10% with xylene, and wiping water: solvent diluted ink was inserted 1: 1 into the test tube. To do. Thereafter, the test tube is stirred up and down, and the solubility in wiping water is observed in the test tube state. When dissolution in wiping water is sufficient, wiping water is also colored and dissolves uniformly. When the dissolution in wiping water is insufficient, a separating layer is generated between wiping water and diluted ink. The solubility is evaluated in 5 stages. High solubility 5 小 1 Low solubility In addition, when printing on the actual machine using the ink, those that have a solubility in wiping water of 3 or less cannot be wiped off sufficiently, so the printed matter will become dirty. Will occur. Therefore, 4 or more of solubility evaluation in wiping water is required.

As for the blocking test, it was confirmed that the printed material with intaglio printing was stored at 25 ° C. and 60 ° C. for 5 days under a load of 100 g / cm ² for 5 days. The set-up state was evaluated by a five-step evaluation. It is necessary not to be completely reversed, and those of 4 or less are insufficient for practical use.

  The present invention has excellent surface curability by active energy ray curing as in the examples, does not cause set-off or blocking that occurs with high-speed printing, and is dissolved or dispersed in an alkaline aqueous solution in the wiping process. Another object is to provide an active energy ray-curable ink composition for intaglio printing and a printed product thereof.

Claims (5)

  An active energy ray-curable ink for intaglio printing comprising a carboxyl group-containing acrylate oligomer having an acid value of 50 to 300 mgKOH / g, a photopolymerizable acrylate monomer excluding the carboxyl group-containing acrylate oligomer, a photoinitiator, and a pigment. Composition.   2. The active energy ray-curable ink composition for intaglio printing according to claim 1, wherein the carboxyl group-containing acrylate oligomer has a cyclic structure in the molecule.   The active energy ray-curable ink composition for intaglio printing according to claim 1, wherein the pigment contains an extender pigment.   4. The active energy ray-curable ink composition for intaglio printing according to claim 1, wherein the photoinitiator has an absorption wavelength of 320 to 400 nm.   A printed matter comprising the active energy ray-curable ink composition for intaglio printing according to any one of claims 1 to 4 printed on a substrate.