JP2010235828A - Ink composition for inkjet printing - Google Patents

Abstract

No nozzle clogging or unstable jetting occurs when printing with an ink jet printer, so that a printed matter preferable in terms of print quality can be obtained, an appropriate drying speed of printing can be obtained, and excellent color expression can be obtained. To provide an ink composition for ink jet printing obtained.
An ink composition for ink jet printing comprising a pigment, a binder resin, a pigment dispersant, a solvent, and an antioxidant excluding a benzotriazole series.
[Selection figure] None

Description

  The present invention relates to an ink composition for ink jet printing, and more specifically, since a nozzle clogging or unstable jet does not occur when printing with an ink jet printer, a printed matter preferable in terms of print quality can be obtained, and the printing can be performed appropriately. The present invention relates to an ink composition for ink jet printing which can obtain a drying speed and is excellent in color development.

  Conventionally, many ink-jet printing ink compositions using various solvents have been proposed as ink-jet printing ink compositions comprising a pigment, a binder resin, a pigment dispersant, and a solvent (see, for example, Patent Documents 1 to 6). ).

  When a printed matter is produced by an ink jet printer using a conventional pigment ink composition, nozzles of the ink jet printer are clogged or unstable jets are produced, resulting in an unfavorable print quality, or such a pigment ink. Even if a printed material is produced using the composition, the color may not always be sufficiently developed.

  The above-mentioned causes of nozzle clogging and unstable jetting are generally considered to be due to the ionic impurities in the ink, the pigment and the acidic group of the resin component, etc. corroding the metal parts constituting the inkjet printer head. In order to prevent metal corrosion, a method of adding a rust preventive agent such as benzotriazole is employed.

  It is also known that radicals and peroxides are generated from polymers, ethers, etc. due to heat, oxygen, light, etc., and materials and peroxides that invalidate radicals to prevent chain oxidation degradation. Materials that break down things are used.

  On the other hand, Patent Document 6 suggests that it is desirable to add an antioxidant in the ink in order to prevent the ink from being oxidized over time, but which composition of the ink oxidizes and affects the ejection of the ink. Has not been elucidated.

JP 2000-044858 A JP 2001-342388 A JP 2002-338863 A JP 2006-056990 A JP 2006-06991 A JP 2007-291253 A

  The present invention has been made in order to solve the above-mentioned problems or to provide an alternative, and does not cause clogging of nozzles or unstable jets when printing with an ink-jet printer. An object of the present invention is to provide an ink composition for ink jet printing which can provide a printed material preferable in terms of printing quality, can obtain an appropriate drying speed for printing, and is excellent in color development.

  As a result of diligent investigations to achieve the above object, the present inventors have found that an ink jet printer head because the binder resin in the ink, particularly the ether solvent, generates radicals and peroxides, and undergoes oxidative degradation in a chained manner. It was found that the metal parts of the steel were corroded, and nozzle clogging and unstable injection occurred. In addition, the water-repellent film on the ink jet printer head surface is corroded by the oxidative deterioration due to the ink, and the eutectoid metal (generally nickel) in the water-repellent film is corroded or peeled off due to the oxidative deterioration. discovered. Therefore, it was found that an excellent ink composition for ink jet printing can be obtained by using a specific antioxidant, and the present invention was completed.

  That is, according to the present invention, there is provided an ink composition for ink jet printing comprising an antioxidant other than a pigment, a binder resin, a pigment dispersant, a solvent and a benzotriazole series.

  By using the ink composition for ink jet printing of the present invention, nozzle clogging or unstable jetting does not occur when printing with an ink jet printer, so that a printed material preferable in terms of print quality can be obtained, and an appropriate drying speed for printing. In addition, excellent color expression can be obtained.

  Below, the ink composition for inkjet printing of this invention is demonstrated concretely.

  In the ink composition for ink jet printing of the present invention, it is essential to use an antioxidant other than the benzotriazole type.

  Examples of the antioxidant used in the present invention include citric acid and derivatives, tartaric acid, gallic acid and derivatives, ascorbic acid and salts, erythorbic acid and salts, catechins, chlorogenic acids, sulfites, and other antioxidants, radical supplements Agents, peroxide decomposers, ultraviolet absorbers, and the like. From the viewpoint of oxidation resistance, radical scavengers, peroxide decomposers, and ultraviolet absorbers are preferred.

Preferably, the radical scavenger is dibutylhydroxytoluene, butylhydroxyanisole, 2,6-di-t-butyl-4-methylphenol, stearyl-β- (3,5-di-butyl-4-hydroxyphenyl) propionate, 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 4 , 4′-butylidenebis (3-methyl-6-tert-butylphenol), tetrakis (methylene-3- (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionate) methane, hinders such as tocopherols Dophenol compounds,
Hindered amines such as ADK STAB LA-57, ADK STAB LA-62, ADK STAB LA-63, ADK STAB LA-67, ADK STAB LA-68, ADK STAB LA-77, ADK STAB LA-82, ADK STAB LA-87 (all manufactured by ADEKA) Compounds.

As the peroxide decomposer, phosphorus compounds such as tris (2,4′-di-t-butylphenyl) phosphite, tris (nonylphenyl) phosphite,
Sulfur compounds such as dilauryl-3,3′-thiodipropionate, dimyristyl 3,3′-thiodipropionate, and distearyl 3,3′-thiodipropionate are listed.

As the UV absorber, benzophenone compounds such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone,
Salicylic acid compounds such as phenyl salicylate and ρ-tert-butylphenyl salicylate,
Cyanoacrylate compounds such as 2-ethylhexyl-2-cyano-3,3′-diphenylacrylate, ethyl-2-cyano-3,3′diphenylacrylate,
Examples thereof include nickel compounds such as nickel bis (octylphenyl) sulfide and nickel-dibutyldithiocarbamate.

  These antioxidants may be used alone or in combination.

  The blending amount of the antioxidant is preferably 0.002 to 1% by mass, more preferably 0.01 to 0.5% by mass of the ink composition. If it is less than 0.002% by mass, it is difficult to suppress oxidation of the resin component or glycol ether compound in the ink. On the other hand, when the content exceeds 1% by mass, there is no problem in suppressing the oxidation of the resin component and glycol ether in the ink, but there is a tendency to deteriorate the properties of the ink film.

  The solvent used in the present invention preferably contains at least one glycol ether compound because the stability of the pigment dispersion is good and the adhesion between the ink and the substrate is good. As the glycol ether compound, (poly) alkylene glycol (di) alkyl ether is preferable, and (di) ethylene glycol (di) alkyl ether, triethylene glycol (di) alkyl ether, and (di) propylene glycol ( And di) alkyl ethers.

As a glycol ether compound, for example,
Ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, ethylene glycol diethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol monobutyl ether, Ethylene glycol ethers such as triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether;
Propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol diethyl ether, etc. Mention may be made of propylene glycol ethers and mixtures thereof. Among these, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol dimethyl ether are more preferable.

Solvents other than glycol ether compounds include alcohols such as ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, tridecyl alcohol, cyclohexyl alcohol, 2-ethylhexyl alcohol; ethyl acetate, isopropylene acetate, acetic acid Esters such as n-butyl, methyl lactate, ethyl lactate, butyl lactate;
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, diacetone alcohol; other heterocyclic compounds such as toluene, xylene, acetonitrile, γ-butyrolactone, γ-valerolactone, N-methyl-2-pyrrolidone, N -Nitrogen-containing compounds such as ethyl-2-pyrrolidone.

  The blending amount of the solvent is determined in consideration of the viscosity, surface tension and the like of the ink composition, and is preferably 15 to 95% by mass of the ink composition, and more preferably 55 to 90% by mass.

  The ink composition for ink-jet printing of the present invention contains a binder resin in the same manner as a normal ink composition for ink-jet printing. The binder resin used in the present invention may be any binder resin commonly used in ordinary ink-jet printing ink compositions, and is not particularly limited, but in the present invention, as such a binder resin, a vinyl chloride copolymer resin, Either a polyester resin or an acrylic resin is preferable. For example, when the base material is vinyl chloride, a vinyl chloride copolymer resin is preferable from the viewpoint of ink adhesion. In this case, the vinyl chloride copolymer resin may be used alone, but the vinyl chloride copolymer resin and other resins may be used in combination. The amount of the binder resin is determined in consideration of the ink adhesion, the viscosity of the ink composition, the surface tension, and the like, and is preferably 0.5 to 15% by mass of the ink composition, and more preferably 1 to 10%. % By mass.

  Various vinyl chloride copolymer resins can be used, and examples thereof include copolymer resins of vinyl chloride and other monomers such as vinyl acetate, vinylidene chloride, acrylic, and maleic acid. Preferred vinyl chloride copolymer resins include vinyl chloride-vinyl acetate copolymer resins obtained by copolymerizing vinyl chloride and vinyl acetate, particularly copolymer resins having a molecular weight of 30,000 or less.

  There is no restriction | limiting in particular as said other resin, Any resin used for the normal ink composition for inkjet printing can be used. For example, epoxy resin, phenol resin, novolak resin, acrylic resin, rosin-modified phenol resin, polyester resin, amino resin such as melamine, benzoguanamine, polyamide resin, cellulose diacetate, cellulose triacetate, nitrocellulose, cellulose nitrate, cellulose propionate, Examples thereof include cellulose ester resins such as cellulose acetate butyrate, cellulose ether resins such as methyl cellulose, ethyl cellulose, benzyl cellulose, trityl cellulose, cyanethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, and aminoethyl cellulose, and vinyl acetate copolymer resins.

The pigment used in the ink composition for ink jet printing of the present invention may be any pigment commonly used in ink compositions for ink jet printing, for example,
Pigment Yellow 12, 13, 14, 17, 20, 24, 31, 42, 53, 55, 74, 83, 86, 93, 109, 110, 117, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 166, 168, 180, 181, 184, 185,
Pigment Orange 16, 36, 38, 43, 51, 55, 59, 61, 64, 65, 71,
Pigment Red 9, 48, 49, 52, 53, 57, 97, 101, 122, 123, 149, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 244, 254,
Pigment violet 19, 23, 29, 30, 32, 37, 40, 50,
Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 30, 60, 64, 80,
Pigment Green 7, 36,
Pigment brown 23, 25, 26,
Pigment Black 1, 7, 26, 27, 28,
Examples thereof include titanium oxide, iron oxide, ultramarine, yellow lead, zinc sulfide, cobalt blue, barium sulfate, and calcium carbonate. The blending amount of the pigment can be arbitrarily determined depending on the kind of the pigment to be used and the like, but is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass of the ink composition.

  The pigment dispersant used in the ink composition for ink jet printing of the present invention may be any pigment dispersant commonly used in ordinary ink jet printing ink compositions, but two or more amides per molecule. A polyester polyamide resin having a group and having a number average molecular weight of 2,000 to 15,000 is preferred. Such a polyester polyamide resin is produced by reacting an acid-terminated polyester resin with a polyamine compound having two or more amino groups in one molecule. Examples of such polyester polyamide resin include Solsperse 32000, Solsperse 32500, Solsperse 32600, Solsperse 33500, Solsperse 34750, Solsperse 35100, Solsperse 37500 (manufactured by Lubrizol), Dispersic 9077 (manufactured by Big Chemie). be able to. The blending amount of the pigment dispersant is determined depending on the type of pigment to be used, and is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass of the ink composition.

  In the polyester polyamide resin as described above, when the number of amide groups is 1 or less per molecule, the pigment dispersibility tends to be insufficient, and when the number average molecular weight is less than 2,000, The pigment dispersion stability tends to be insufficient, and when the number average molecular weight exceeds 15,000, the dispersibility in the ink composition tends to be insufficient.

  Moreover, the ink composition for inkjet printing of this invention can contain an electrical conductivity adjusting agent depending on necessity. The blending amount of such a conductivity adjusting agent is usually preferably from 0.1 to 10% by mass, more preferably from 0.5 to 5% by mass of the ink composition.

  In addition, the ink composition for ink jet printing of the present invention needs to have characteristics adapted to the ink jet printing method in the same manner as a normal ink composition for ink jet printing, and for that purpose, the viscosity of the ink composition is reduced. It is desirable that the surface tension is 1 to 100 mPa · s (20 ° C.), the surface tension is 20 to 60 mN / m, and the specific gravity is 0.8 to 1.2.

  The ink composition for ink jet printing of the present invention can be prepared by stirring and mixing the components, and then filtering and purifying with a filter having a pore size of about 1/10 or less of the nozzle diameter of the ink jet printer to be used. .

  The ink composition for inkjet printing of the present invention can be used for various types of inkjet printers. Examples of such an ink jet printer include a charge control method and a method in which an ink composition is ejected by an ink on demand method. The ink composition for inkjet printing of the present invention can be suitably applied particularly to printing by a large inkjet printer using a large format, for example, printing by an inkjet printer for the purpose of printing on an outdoor article such as a sign display. Further, the contrast is clear in the color graphic printing portion and the video recording drawing, and the reproducibility of the image is remarkably improved.

  The printed surface (ink composition) after inkjet printing is dried at room temperature to several hundreds of degrees C to form a dry film. In addition, about the base material used as the object of printing by this invention, if it does not deform | transform or change in quality on the conditions which dry a printing surface (ink composition), it will not restrict | limit in particular. Examples of such a substrate include the surface of a substrate such as metal, glass and plastic, paper coated with a resin on the surface, a transparent sheet for an overhead project, and outdoor articles such as a sign display.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Hereinafter, both “parts” and “%” are based on mass.

<Examples 1-61 and Comparative Examples 1-9>
The ink compositions of Examples 1 to 61 and Comparative Examples 1 to 9 were prepared by kneading the components shown in Tables 1 to 6 and the mixtures contained in the blending amounts (parts by mass) with a sand mill for 3 hours.

  The pigments used were carbon black as a black pigment, pigment red 122 as a magenta pigment, pigment blue 15: 3 as a phthalocyanine blue, pigment yellow 150 as a yellow pigment, and titanium dioxide as a white pigment.

  As for the resin used, vinyl chloride copolymer resin is Solvain CL (manufactured by Nisshin Chemical Co., Ltd., vinyl chloride-vinyl acetate copolymer, number average molecular weight = 25000, Tg = 70 ° C.), polyester resin is Byron GK810 (manufactured by Toyobo Co., Ltd.) , Number average molecular weight = 6000, Tg = 46 ° C., acid value = 5 mg KOH / g, hydroxyl value = 19 mg KOH / g, acrylic resin is Dianal MB2660 (manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight = 65000, Tg = 52 ° C., Acid value = 3 mg KOH / g).

  Antioxidants used were Yoshinox BHT (manufactured by API Corporation, dibutylcidroxytoluene) as a hindered phenol compound, and Tinuvin 123 (manufactured by Ciba, decanodioic acid bis (2,2,6) as a hindered amine compound. , 6-tetramethyl-1- (octyloxy) -4-hydridinyl) ester), phosphorus compound, ADK STAB 1178 (manufactured by ADEKA, tris (monononylphenyl) phosphite), sulfur compound, Sinox DL (Cipro Kasei Co., didodecylthiodipropionate), benzophenone-based compound as Seesorb 102 (Cipro Kasei Co., Ltd., 2-hydroxy-4-n-octyloxybenzophenone), salicylic acid-based compound as phenyl salicylate (Wako Pure) Manufactured by Yakuhin Kogyo Co., Ltd. Seesorb 502 (manufactured by Cypro Chemical Co., Ltd., 2′-ethylhexyl-2-cyano-3,3-diphenyl acrylate) as a noacrylate compound, and Seesorb 612NH (manufactured by Cypro Chemical Co., Ltd., [2,2′- Thiobis (4-tert-octylphenolate)]-2-ethylhexylamine nickel (II)).

  The corrosion inhibitor used is carboxybenzotriazole.

  For the obtained ink compositions of Examples 1 to 61 and Comparative Examples 1 to 9, the viscosity, average particle diameter, dispersion stability, and nozzle discharge stability were tested and measured by the following methods, respectively. Evaluated by criteria.

  As for the pigment dispersant used, polyester polyamide resin A was Solsperse 32000 (manufactured by Lubrizol, solid concentration 100%, number average molecular weight = 1500), polyester polyamide resin B was BYK9077 (manufactured by BYK Chemie, solid concentration 99%, Number average molecular weight = 1400).

<Viscosity measurement>
The viscosity of each ink composition was measured at 20 ° C. using a viscoelasticity measuring device (“Pysica MCR301” manufactured by Anton Paar).

<Average particle size measurement>
The particle diameter of the pigment of each ink composition was measured by an average particle size (D50) using a dynamic light scattering theoretical particle size distribution analyzer (“UPA-EX150” manufactured by Nikkiso Co., Ltd.).

<Dispersion stability>
After each ink composition was stored in a sealed container at 60 ° C. for 1 month, it was taken out and its viscosity and particle size were measured as described above, and the changes before and after the test were evaluated according to the following criteria.
A: Changes in viscosity and particle size are both within ± 5%.
◯: At least one of changes in viscosity and particle diameter exceeds ± 5% and within ± 10%.
X: Change in viscosity and particle diameter, at least one of which exceeds ± 10%.

<Nozzle discharge stability>
Images were printed on a vinyl chloride substrate for 8 hours continuously using a large format inkjet printer, then stopped for 1 week in an environment of temperature 40 ° C. and humidity 65%, and printed again for 1 hour. The printed state was visually evaluated according to the following criteria.
(Double-circle): It can print correctly in a predetermined position at 90% or more of the printed dots.
○: Printing can be correctly performed at a predetermined position with 80% or more and less than 90% of the printed dots.
Δ: Dot bending occurs at 20% or more and less than 70% of the printed dots.
×: Dot bending occurs in 70% or more of the printed dots.

  The measurement results and evaluation results were as shown in Tables 1 to 6.

  As is apparent from the data shown in Tables 1 to 5, the ink compositions of Examples 1 to 61 of the present invention obtained excellent evaluation results for each test item, and inks with good printing were obtained.

  On the other hand, as apparent from the data shown in Table 6, the ink compositions of Comparative Examples 1 to 9 were clogged with nozzles, resulting in poor printing. In Comparative Example 9 using only carboxybenzotriazole, which is a corrosion inhibitor such as metal, the dispersion stability was poor.

Claims (14)

  An ink composition for ink jet printing comprising a pigment, a binder resin, a pigment dispersant, a solvent, and an antioxidant excluding a benzotriazole type.   The ink composition for ink jet printing according to claim 1, wherein the antioxidant is 0.002 to 1% by mass of the ink composition.   The ink composition for inkjet printing according to claim 1 or 2, wherein the antioxidant is a radical scavenger.   The ink composition for ink jet printing according to claim 3, wherein the radical scavenger is a hindered amine compound or a hindered phenol compound.   The ink composition for ink jet printing according to claim 4, wherein the hindered phenol compound is dibutylcidoxytoluene.   The ink composition for ink jet printing according to claim 1 or 2, wherein the antioxidant is a peroxide decomposer.   The ink composition for ink jet printing according to claim 6, wherein the peroxide decomposing agent is a phosphorus compound or a sulfur compound.   The ink composition for ink jet printing according to claim 1 or 2, wherein the antioxidant is an ultraviolet absorber.   The ink composition for inkjet printing according to claim 8, wherein the ultraviolet absorber is selected from the group consisting of a benzophenone compound, a salicylic acid compound, a cyanoacrylate compound, and a nickel compound.   The ink composition for inkjet printing according to any one of claims 1 to 9, comprising at least one glycol ether compound as the solvent.   The ink composition for ink jet printing according to claim 10, wherein the glycol ether compound is a (poly) alkylene glycol (di) alkyl ether.   The ink composition for inkjet printing according to claim 11, wherein the glycol ether compound is (di) ethylene glycol (di) alkyl ether, triethylene glycol (di) alkyl ether, or (di) propylene glycol (di) alkyl ether. .   The glycol ether compound is ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene The ink composition for inkjet printing according to claim 12, which is glycol dimethyl ether.   The ink composition for inkjet printing according to any one of claims 1 to 13, wherein the binder resin is at least one of a vinyl chloride copolymer resin, a polyester resin, and an acrylic resin.