TWI488923B - Ink composition for ink-jet printing - Google Patents

Description

Ink composition for inkjet printing

The present invention relates to a reactive ink composition suitable for printing or coating by an ink jet method. In particular, it relates to an ink composition which can be immediately hardened by irradiation with an active-energy-ray such as ultraviolet (UV) or electron beam (EB).

Printing or coating by inkjet printing is not only for printing on paper, but also for printing or patterning of plastic materials or fiber materials, and in recent years, it has also been used for manufacturing. Wiring of electronic and electrical devices, formation of a resist pattern, and the like. In particular, in the case of using an ink composition which can be immediately cured by active energy rays, the cured ink can be made to have water resistance, solvent resistance, rubfastness, and the like, which is preferable.

In the ink composition for inkjet printing disclosed in Patent Document 1, A crosslinkable (polyfunctional) monomer constituting a main hardening component is a reactive functional group introduced at the end of an alkylene oxide adduct (adduct) of a neopentyl alcohol polymer. Founder. However, according to a specific example, a crosslinkable monomer (Example 1) obtained by introducing an acrylate group at a terminal has a viscosity at 25 ° C of 580 mPas and is high. Further, the frictional fastness of the obtained cured product may be such that it is not scratched or scratched by the nail (paragraphs 100 to 102). That is, it is generally considered that it is desired to improve the viscosity and the strength of the cured product or the fastness property.

The ink composition for inkjet printing disclosed in Patent Document 2 is characterized by containing a specific photo-polymerization initiator and a poly-oxygen system (silicone-based as a surface regulator). Based on a compound or the like, for example, in Example 18 and Example 23, dipentaerythritol-hexaacrylate was used together with a diacrylate compound as a crosslinkable (polyfunctional) monomer (Table 3 and Table 4). . However, in Example 18 in which the content of hexaacrylate was small, although the viscosity at 25 ° C was as low as 15 mPas, the evaluation of the hardenability was "Δ", which was not necessarily sufficient (Table 8). In addition, in Example 23, in which the hexaacrylate content was twice or more that of Example 18, the evaluation of the hardenability was "○" and was good, but the viscosity was 29 mPas, and Example 18 was obtained. About 2 times (Table 9). That is, it is generally considered that further improvement is desired so that the viscosity and the hardenability become good at the same time.

Further, the ink composition for inkjet printing disclosed in Patent Document 3 is characterized in that it contains dineopentaerythritol hexaacrylate modified with ε-caprolactone (ε-caprolactone), and allyl propylene Aldyl glycol. Although it inhibits hardening shrinkage by modifying the crosslinkable monomer with caprolactone, since the length of the segment of caprolactone is large, it is conceivable that the crosslinking density will be lowered and the hardened substance will be hardened. Hardness and friction fastness are not necessarily sufficient.

On the other hand, Patent Document 4 discloses that a UV curable resin is applied by an inkjet method to provide a photoresist pattern for manufacturing a printed board.

[Previous Technical Literature] (Patent Literature)

Patent Document 1: Japanese Patent Laid-Open No. 2011-132386

Patent Document 2: Japanese Patent Laid-Open No. 2009-275175

Patent Document 3: Japanese Patent Laid-Open No. 2010-202736

Patent Document 4: Japanese Patent Laid-Open No. 2012-184411

The present invention has been made in view of the above, and a technical problem thereof is to provide an ink composition for inkjet printing which can maintain the viscosity of a crosslinkable monomer and shrinkability at the time of hardening to be low, and to make a hardenability and a cured product. The friction resistance is improved.

The inventors of the present invention conducted intensive studies to solve the above problems, and found that if an alkylene oxide-modified dipentaerythritol (meth)acrylate is used as a crosslinkable monomer When the amount of the alkylene oxide addition moth used as the modified (meth)acrylic acid dipentaerythritol ester is moderately small, the viscosity and the shrinkability at the time of hardening can be kept low. Further, the present invention has been completed based on the findings that the hardenability and the rubbing fastness of the cured product are improved.

That is, the ink composition for inkjet printing of the present invention is one comprising an alkylene oxide (meth)acrylic acid pentaerythritol having a structure represented by the following general formulae (I) and (II).

Wherein, in the formula (I), R represents a substituent represented by the formula (II), and AO represents a group selected from -CH ₂ CH ₂ O-, -CH ₂ CH(CH ₃ )O-, -CH One or more of ₂ alkylene oxide units represented by ₂ CH ₂ CH ₂ CH ₂ O- or -CH ₂ CH(C ₂ H ₅ )O-, indicating the average degree of polymerization of the added alkylene oxide chain L is 0 < L ≦ 5, the average value of m is greater than 0 and 5 or less, and the average addition molar number of the alkylene oxide L × m is 0 < L × m ≦ 5, n is 1 or 2, o The average value is 0 or more and 6 or less, and the total value of m, n, and o is 6; in the general formula (II), R ² represents a hydrogen atom or a methyl group.

The ink composition for inkjet printing of the present invention is obtained by including a crosslinkable monomer having a structure represented by the above formulas (I) and (II), and A non-crosslinkable monomer reactive with the crosslinkable monomer is included as needed. In addition, a pigment or a dye as a coloring component, a metal fine powder which imparts conductivity or the like, and the like are contained as needed, and when a pigment is used, a pigment dispersing agent is contained as needed.

The ink composition for inkjet printing of the present invention is preferably completely free of a solvent. Further, in the case of containing a solvent, it is also 5% by weight or less, preferably 1% by weight or less. The ink composition for ink jet printing of the present invention preferably has a viscosity at 25 ° C of 1 to 50 mPas, more preferably 3 to 15 mPas. The viscosity was measured in accordance with JIS K 5600-2-3 of Japan.

The ink composition for inkjet printing of the present invention can be cured by, for example, irradiation with an active energy ray such as ultraviolet rays, electron beams, blue visible rays, or gamma rays. In the case of using ultraviolet rays, the light source may use light having a wavelength in the range of 150 to 450 nm, and if necessary, a photopolymerization initiator. Further, heat by infrared rays, far infrared rays, hot air, high frequency heating, or the like may be used in combination. The ratio of the energy ray hardening component, particularly the ultraviolet curable component, in the portion other than the pigment of the ink composition for inkjet printing of the present invention is usually 70 to 95% by weight, typically 80 to 90% by weight. . Further, the curing by the active energy ray irradiation may be performed, for example, by arranging the irradiation lamp directly behind the nozzle (nozzle) and substantially simultaneously with the coating, or after the coating pattern is completed. It is placed in the irradiation device.

<Alkylene oxide modified dipentaerythritol (meth)acrylate>

The ink composition for inkjet printing of the present invention has a structure represented by the above formulas (I) and (II) as a crosslinkable monomer. In formula (I), AO represents -CH ₂ CH ₂ O-, or -CH ₂ CH(CH ₃ )O-, or -CH ₂ CH ₂ CH ₂ CH ₂ O-, or -CH ₂ CH(C An alkylene oxide unit represented by ₂ H ₅ )O-. That is, it means any one of an ethylene oxide (EO) unit, a propylene oxide (PO) unit, and a butylene oxide unit, from the viewpoints of viscosity, photosensitivity, and polymerization rate. It is preferably an ethylene oxide unit. These alkylene oxide units may be present alone or in combination of two or more.

The average addition molar number (L x m) of dipentaerythritol per 1 mole of alkylene oxide is more than 0 and 5 or less, preferably 1 or more and 3 or less. When the average molar amount of the alkylene oxide is less than this range, the effect of lowering the viscosity of the crosslinked monomer and the effect of improving the photosensitivity are insufficient. Further, when it is larger than this range, the viscosity of the crosslinkable monomer becomes large, so that if the discharge property is desired to be good, it is necessary to increase the blending amount of the monofunctional (diluted) monomer. Further, since the alkylene oxide chain becomes long, the crosslinking density is also lowered by a corresponding amount, and the strength of the cured product is lowered. On the other hand, it represents the average polymerization of the added alkylene oxide chain. The degree L is 0 < L ≦ 5, preferably 1 ≦ L ≦ 3. Further, the average value of m is more than 0 and 6 or less, preferably 1 or more and 2 or less. The average value of n indicating the residual hydroxyl group is 0 or more and less than 6, preferably 1 or more and 2 or less. The average value of 0 is 0 or more and 6 or less, preferably 0 or more and 4 or less. The total value of these m, n, and o is 6.

R is a (meth)acryloyl group represented by the formula (II), and in the formula (II), R ² is a hydrogen atom or a methyl group, and a wavy line Part) indicates the key portion.

That is, the crosslinking monomer having a part or all of the six hydroxyl groups of dipentaerythritol is composed of a plurality of kinds of ethylene oxide, propylene oxide, butylene oxide, or the like. The spacer is converted into a structure of a (meth) acrylate group represented by the general formula (II). Further, since one or two hydroxyl groups having no (meth) acrylate group remain as a hydrophilic group, adhesion to various substrates and the like is facilitated.

<Method for producing alkylene oxide modified (methylene) acrylated neopentyl glycol ester>

The above crosslinkable monomer can be produced by, for example, the method hereinafter, but the production route thereof is not particularly limited, and any production method can be employed.

The alkylene oxide upgrading method using dipentaerythritol as a raw material can be arbitrarily selected. As a general method, in addition to a method of using an alkylene oxide such as ethylene oxide, propylene oxide or butylene oxide, an ethylene carbonate, a propyl carbonate, or a carbonic acid ester may be used. a method of a cyclic carbonate such as an ester; and a method of using ethylene chlorohydrin.

Further, in the production method described below, since the (meth)acrylic compound used as the raw material of the above-mentioned crosslinkable monomer is highly polymerizable, a polymerization inhibitor can be suitably used to make it in the production. Do not polymerize during storage or product storage. Examples of the polymerization inhibitor include hydroquinones such as p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, and 2,5-diphenyl-p-benzoquinone; tetramethylpiperidinyl-N- N-oxyl radicals such as tetramethylpiperidinyl-N-oxy radical (TEMPO); substituted catechols such as tertiary butyl catechol; An amine such as phenothiazine, diphenylamine or phenyl-β-naphthylamine; Cupferron, nitrosobenzene, picric acid, molecular oxygen, sulfur , copper (II) chloride [copper (II) chloride] and the like. Among them, hydroquinones, thiophenes And N-oxyl radicals are preferred in terms of versatility and polymerization inhibition efficiency.

The addition amount of the polymerization inhibitor is preferably about 10 ppm or more, preferably 30 ppm, based on the compound represented by the formula (I) with respect to the object. The upper limit is usually 5,000 ppm or less, preferably 1,000 ppm or less. If it is too small, sufficient polymerization inhibiting effect will not be exhibited, and there is a risk of polymerization during production or storage of the product; if too much, the curing or polymerization reaction may be inhibited conversely. Therefore, there is a concern that the sensitivity of the compound of the present invention alone or as a polymerizable resin composition is lowered, the crosslinking property of the cured product is poor, and the physical properties such as mechanical strength are lowered, which is not preferable.

In the case of producing the above-mentioned crosslinkable monomer, a general introduction method of the (meth) acrylate group is a (meth) acrylate having a desired structure corresponding to methyl acrylate or methyl methacrylate. Transesterification method; acid chloride method using (meth)acrylic acid chloride; using N,N'-dicyclohexylcarbodiimide, chlorination 2- 2-chloro-1,3-dimethylimidazolium chloride, propanephosphonic anhydride, carbonyldiimidazole (CDI), WSCD (water-soluble carbodiimide) A method of a condensation agent or the like; a dehydration esterification method in which azeotropic-dehydration is carried out with (meth)acrylic acid in the presence of an acid catalyst. In the following, regarding the esterification reaction of a representative alkylene oxide-modified dipentaerythritol, conditions practicable in terms of production are disclosed.

The reaction can be carried out by distilling off the formed water in the presence of an acid catalyst with (meth)acrylic acid and alkylene oxide-modified dipentaerythritol. The acid to be used is not particularly limited as long as it is an acid which is usually used in the esterification reaction. For example, an inorganic acid such as sulfuric acid or hydrochloric acid; an organic sulfonic acid such as p-toluenesulfonic acid or methanesulfonic acid or camphorsulfonic acid; an acid ion exchange resin; and a boron fluoride-ether complex. (Lewis acid) such as a fluorinated boron-ether complex; a water-soluble Lewis acid such as a lanthanoid triflate or the like. These acids may be used singly or in combination of two or more kinds of any of them.

The amount of the acid to be used is preferably 0.1 mole equivalent or more, preferably 0.5 mole equivalent or more, relative to the alkylene oxide-modified dipentaerythritol of the substrate. On the other hand, the upper limit is not limited and is usually 20 mol equivalent or less, preferably 10 mol equivalent or less. If the amount of the acid catalyst is too small, the progress of the reaction may be delayed or stopped, which is not preferable, and if it is too much, the product may be colored or the catalyst may remain. The problem, or the tendency to form undesirable side reactions such as Michael addition product.

The reaction can be carried out in either a solvent-based or solvent-free system, but it is considered from the viewpoint of formation of by-products and handling in the process. Preferably, it is a solvent system. When a solvent is used, the solvent to be used is not particularly limited, and an aromatic hydrocarbon solvent such as toluene or xylene or an aliphatic hydrocarbon solvent such as hexane or heptane is suitable; An ether-based solvent such as a group ether, tetrahydrofuran, monoethylene glycol dimethyl ether or diethylene glycol dimethyl ether; or a halogen-based solvent such as dichloromethane, chloroform or carbon tetrachloride. These solvents may be used singly or in combination with any plural number of solvents.

In the case of using a solvent, the amount of the raw material alkylene oxide-modified dipentaerythritol is usually 1% by mass or more, preferably 20% by mass or more, and the upper limit is not particularly limited, and is usually 80. The mass% or less is preferably 70% by mass or less. The reaction is usually carried out at a temperature higher than the boiling point of the solvent to be used, and is carried out while distilling off the formed water. However, when the reaction using the above (meth)acrylic acid chloride or a condensing agent is carried out, the reaction may be carried out at a temperature below the boiling point of the solvent or under ice cooling. The reaction time can be arbitrarily selected, and the end point of the reaction can be confirmed by measuring the amount of water formed and the acid value in the system.

The reaction time is usually 30 minutes or longer, preferably 60 minutes or longer, and the upper limit is not particularly limited, and is usually 20 hours or shorter, preferably 10 hours or shorter.

<Refining method>

The compound represented by the formula (I) can be produced by the above reaction, and can be purified without any particular limitation using the purification method previously used. For example, a distillation method, a recrystallization method, an extraction washing method, an adsorption treatment method, and the like. In the case of performing distillation, a simple distillation, a precision distillation, a film distillation, a molecular distillation, or the like can be arbitrarily selected.

<Method for preserving (meth) acrylate monomer>

The above crosslinkable monomer is preferably stored in a dark place due to its polymerizability. Further, in order to prevent polymerization, the above polymerization inhibitor may be stored using the above amount.

<Pigments, dyes or metal fine powders, etc.>

In the ink composition for inkjet printing of the present invention, a pigment or a dye may be blended as a colorant. In order to obtain weather resistance, a pigment is preferable, and either or both of an inorganic pigment and an organic pigment can be used. Further, as a black pigment or for the purpose of shielding, carbon black produced by a conventional method such as a contact method, a furnace method, or a thermal method may be blended. Further, in order to impart conductivity, various metal powders, graphite powders, and the like may be blended.

Examples of the inorganic pigment include chrome yellow, zinc yellow, iron blue (Prussian blue), barium sulfate, cadmium red, titanium oxide, and zinc white. (zinc white) (zinc oxide), red iron (red ocher) (Bengala), alumina, calcium carbonate, ultramarine, graphite, and titanium black. Examples of the organic pigment include β-naphthol-based, β-hydroxynaphthoic anilide-based, and acetoacetic anilide-based. , soluble azo pigments such as pyrazolone-based; β-naphthol-based, β-hydroxynaphthoic acid-based, β-hydroxynaphthoic acid anilide, acetamidine An insoluble azo pigment such as acetoacetic anilide-based monoazo, acetoacetic anilide-based disazo, pyrazolone-based or the like; Copper phthalocyanine blue, copper phthalocyanine blue, sulfonated copper phthalocyanine blue, metal-free phthalocyanine, etc. Isoindolinone-based, quinacridone-based, dioxins A polycyclic or heterocyclic compound such as dioxazine-based, perinone-based, and perylene-based. Further, examples of the carbon black as the black pigment include HCF #2650, HCF #2600, HCF #2350, HCF #2300, MCF #1000, MCF #980, manufactured by Mitsubishi Chemical Co., Inc. MCF #970, MCF #960, MCF88, LFFMA7, MA8, MA11, MA77, MA100; and Printex 95, Printex 85, Printex 75, Printex 55, Printex 45, etc. manufactured by Degussa-Huls Corporation. Further, examples of the metal powder to which conductivity is imparted are fine powder of aluminum or the like.

The particle diameter (weight average particle diameter) of the pigment or the like is preferably from 0.01 μm to 2.0 μm, more preferably from 0.01 μm to 1.0 μm. The blending amount of the pigment or the like is 1 to 60% by weight, preferably 5 to 40% by weight, based on the ink composition for inkjet printing. In the case of blending a pigment, it is preferred to simultaneously blend each pigment dispersant or pigment derivative as a pigment dispersant, and specific examples thereof include, for example, an ionic or nonionic surfactant, or an anion. A cationic, cationic or nonionic polymeric compound. Among these, a polymer compound containing a cationic group or an anionic group is preferred from the viewpoint of dispersion stability. For example, polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyacrylic acid, carboxylate-containing carboxylate, long-chain polyamine amide and high molecular weight acid ester salt, high molecular weight polycarboxylate can be used. Acid salts, salts of long chain polyamine amides and polar acid esters, high molecular weight unsaturated acid esters, high molecular copolymers, modified polyurethanes, modified polyacrylates, polyether esters Anionic active agent, naphthalenesulfonic acid-formalin condensate salt, aromatic sulfonic acid formaldehyde condensate salt, polyoxyethylene alkyl phosphate (polyoxyethylene alkylphosphoric acid ester), polyoxyethylene nonylphenyl ether, stearylamine acetate. A commercially available pigment dispersant may be mentioned, such as: SOLSPERSE manufactured by The Lubrizol Corporation, DISPERBYK manufactured by BYK Chemie Corp., EFKA manufactured by EFKA Additives BV, etc. . Specific examples of the pigment derivative include a pigment derivative having a dialkylaminoalkyl group, a pigment derivative having a dialkylaminoalkylsulfonate sulfonate group, and the like. The blending amount of the pigment dispersant or the like is preferably 0.05 to 5% by weight in the ink composition for ink jet printing.

<Other energy ray polymerizable monomers>

Other crosslinkable monomers may be used together with the above crosslinkable monomer, and a non-crosslinkable monomer may be used together with such a crosslinkable monomer. In the case where they are used in combination as described above, the ratio of the crosslinkable monomer to the energy ray polymerizable monomer may be 55 to 90% by weight, preferably 65 to 80% by weight. As the monomer to be used in combination as described above, any one can be used as long as it can simultaneously carry out polymerization reaction when irradiated with an energy ray. Specific examples thereof include (meth) acrylates having 4 to 30 carbon atoms, (meth) acrylamides having 5 to 35 carbon atoms, aromatic vinyls having 5 to 35 carbon atoms, and carbon number. 2 to 20 vinyl ethers and other radical polymerizable compounds. Among them, preferred is (meth)acrylate [(meth)acrylate] or (meth) propyl Ethylamine [(meth)acrylamide]. In the present specification, the case of either or both of "acrylate" and "methacrylate" is referred to as "(meth)acrylate".

Examples of the non-crosslinkable (monofunctional) (meth) acrylate include hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and (meth) acrylate. Tertiary octyl ester, isoamyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, Cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, borneyl (meth)acrylate, isobornyl (meth)acrylate, (methyl) Benzyl acrylate, 2-ethylhexyl diglycol (meth)acrylate, butoxyethyl (meth)acrylate, 2-chloroethyl (meth)acrylate Ester, 4-bromobutyl (meth)acrylate, cyanoethyl (meth)acrylate, benzyl (meth)acrylate, butoxymethyl (meth)acrylate, methoxypropenyl acrylate Methoxypropylene monoacrylate), 3-methoxybutyl (meth)acrylate, alkoxymethyl (meth)acrylate, 2-ethylhexylcarbitol (meth)acrylate, alkoxylate (meth)acrylate Ethyl ester, (meth) propyl 2-(2-methoxyethoxy)ethyl acid, 2-(2-butoxyethoxy)ethyl (meth)acrylate, 2,2,2-tetrafluoro(meth)acrylate Ester, (meth)acrylic acid 1H, 1H, 2H, 2H-perfluoro Oxime ester, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-tetramethylphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate , phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, glycidoxybutyl (meth)acrylate, (methyl) Glycidyloxyethyl acrylate, glycidoxypropyl (meth)acrylate, tetrahydrofuran methyl (meth)acrylate, hydroxyalkyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate , 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylic acid Dimethylaminoethyl ester, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, (methyl) ) Trimethoxysilylpropyl (meth)acrylate, trimethoxymercaptopropyl (meth)acrylate, trimethylmercaptopropyl (meth)acrylate, poly(meth)acrylate ring Ethylene oxide monomethyl ether ester De monomethyl ether(meth)acrylate], oligoethylene oxide monomethyl ether (meth)acrylate, poly(meth)acrylate ethylene oxide, oligo(A) Ethylene oxide acrylate, oligo(meth)acrylate oxirane monoalkyl ether ester, poly(meth)acrylic acid oxirane monoalkyl ether ester, (meth)acrylic acid dipropylene glycol ester , poly(meth)acrylic acid propylene oxide monoalkyl ether ester, oligo(meth)acrylic acid propylene oxide monoalkyl ether ester, 2- Methyl propylene methoxyethyl succinic acid, 2-methacryloyloxyhexahydrophthalic acid, 2-hydroxypropyl phthalate 2-methyl propylene oxy ethoxylate 2-methacryloyloxyethyl 2-hydroxypropylphthalate, butoxy diglycol (meth)acrylate, trifluoroethyl (meth)acrylate, perfluorooctyl ethyl (meth)acrylate, (meth)acrylic acid 2-hydroxy-3-phenoxypropyl ester, EO modified (meth)acrylic acid phenol ester, EO modified (meth)acrylic acid cresol ester, EO modified (meth)acrylic acid nonylphenol ester, PO modified Nonyl methacrylate (meth) acrylate, EO modified 2-ethylhexyl (meth) acrylate, and the like.

Examples of the (meth) acrylamide having 5 to 35 carbon atoms include (meth) acrylamide, N-methyl (meth) acrylamide, and N-ethyl (meth) propylene. Indoleamine, N-propyl (meth) acrylamide, N-n-butyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N-butoxymethyl ( Methyl) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-Diethyl(meth)acrylamide and (meth)acryloylmorpholine.

<Polymerization initiator>

As a polymerization initiator, a radical polymerization or a cationic polymerization is mentioned. Energy ray polymerization initiator, for example, having an aromatic ketone, an aromatic sulfonium compound, an organic peroxide, a hexaarylbiimidazole compound, a ketoxime compound, a borate compound, an oxazinium salt compound (azinium) Compound), a metallocene compound, a compound of an active ester compound, and the like.

For example, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenyl ethane-1-one, Xanthone, fluorenone, benzaldehyde, fluorene, guanidine, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorodiphenyl ketone, 4 , 4'-dimethoxydiphenyl ketone, 4,4'-diaminodiphenyl ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1 -(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, oxysulfur Star (thioxanthone), diethyl oxysulfide Star, 2-isopropyloxysulfide Star, 2-chlorosulfur Star, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, 2-benzyl-2-dimethylamino-1- 4-morpholinylphenyl)-butanone-1,4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)one, 2,4,6-trimethylbenzene Mercaptodiphenylphosphine oxide, bis-(2,6-dimethoxybenzylidene)-2,4,4-trimethylpentylphosphine oxide, oligo(2-hydroxy-2-methyl- 1-(4-(1-methylvinyl)phenyl)acetone) and the like.

In addition, a commercially available product of a polymerization initiator of an active energy ray may, for example, be a product name: IRGACURE 184, 369, 651 manufactured by Ciba Specialty Chemicals Co., Ltd. 500, 819, 907, 784, 2959, CGI1700, CGI1750, CGI1850, CG24-61, DAROCUR 1116, 1173; BASF Corporation (BASF Corporation) trade name: LUCIRIN TPO; UCB company trade name: EBECRYL P36; Fratilli Lamberti Product name: ESACURE KIP150, KIP65LT, KIP100F, KT37, KT55, KTO46, KIP75/B, etc.

The amount of the polymerization initiator to be used by the active energy ray may be selected according to a conventional polymerization reaction. For example, the radical polymerization initiator is usually 0.0001 to 10 parts by weight, and preferably 0.001 to 5 parts by weight, based on the total amount of the active energy ray-polymerizable monomer. The temperature at the time of the hardening reaction is usually 0 ° C or higher, preferably 10 ° C or higher, and the upper limit is usually 200 ° C or lower, preferably 100 ° C or lower.

The ink composition for inkjet printing of the present invention may contain 5 to 10% by weight of a tackifier (silane coupling agent) or a sensitizer, or 1 as needed. ~5 wt% of a solvent or the like. Further, in combination with the purpose of use, it may contain inorganic fine particles, a dispersing agent, an antifoaming agent, a leveling agent, a thixotropy imparting agent, a slip additive, a flame retardant, and an antistatic agent. , antioxidants and UV absorbers. Examples of the adhesion imparting agent include γ-aminopropyltrimethoxydecane, γ-aminopropyltriethoxydecane, vinyltriethoxydecane, and γ-glycidoxypropyl group. Triethoxy decane, γ-methyl propylene methoxy propyl trimethoxy decane, urea propyl triethoxy decane, ginsylacetate aluminum [tris (acetylacetonato) aluminum] and acetyl Acetylacetate aluminum diisopropylate and the like. As the sensitizer, ketocoumarin, hydrazine, and oxysulfide are mentioned. Star, diethyl oxysulfide Star, isopropyloxysulfide Star, anthraquinone, naphthiazoline, diacetyl (diacetyl; butane-2, 3-dione), diphenylethylenedione (benzil) and derivatives thereof, perylene and Substituted cockroaches, etc.

Further, examples of the solvent include glycol ethers (ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone) And cyclohexanone, etc.; esters (ethyl acetate, butyl acetate, ethylene glycol alkyl ether acetate and propylene glycol alkyl ether acetate); aromatic hydrocarbons (toluene, xylene (茬), both Metsitylene and limonene, etc.; alcohols (methanol, ethanol, n-propanol, isopropanol, butanol, geraniol, linalool, and citronellol) Citronellol), etc.; and ethers (tetrahydrofuran and 1,8-decyl ether (1,8-cineole), etc.). These may be used alone or in combination of two or more.

The ink composition for inkjet printing of the present invention can be used for printing or coating in a manner other than the inkjet method, as the case may be. For example, conventional coating methods such as spin coating, roll coating, and spray coating, and planographic printing, carton printing, metal printing, offset printing, and net printing can be used. Screen printing and gravure printing.

[Effect of the invention]

In the case of the ink composition for inkjet printing of the present invention, the viscosity of the crosslinking monomer of the main component is significantly lower than that of the commonly used dinet pentaerythritol acrylate, and can be made lower than the prior art. Derivatives. Therefore, in particular, in the case of a solvent-free reactive composition, the content of the monofunctional monomer added for the purpose of lowering the viscosity or adjusting the viscosity can be reduced, or it can be made better without adding it. Further, due to this, the (meth) acrylonitrile group concentration of the polymerizable functional group in the reactive composition can be increased.

Therefore, by incorporating the viscosity of the composition into the ink composition for inkjet printing which is emphasized, the film strength of the ink can be maintained without impairing the discharge property from the nozzle. Also, since the photosensitivity of the crosslinking monomer is high It is also excellent in productivity in the case of dipentaerythritol acrylate. In addition, the shrinkage at the time of hardening can be kept low.

"Embodiment"

In the following, the present invention will be described in more detail by way of examples, but the present invention is not limited by the scope of the invention. In addition, unless otherwise specified, "%" is mass%, and "part" is based on mass.

<Liquid Chromatography-Mass Spectrometry analysis (hereinafter, simply referred to as LC-MS analysis) conditions>

The LC-MS analysis of the examples and comparative examples was carried out under the following conditions:

[LC Part] 1100 Series by Agilent Technologies Corporation

Column: Inertsil ODS-2 (4.6mm φ×250mm, 5μm), dissolving solution: water 80.0%-30min→0.0%, methanol 20.0%-30min→100.0%; column temperature: 40°C, flow rate: 1mL/min Injection volume: 5Ml (200ppm methanol solution), detector: UV, RI

[MS part] JMS T100LP (made by JEOL Ltd.)

Ring lens voltage: 10V, ionization method: APCI+, desolvation chamber temperature: 350 ° C, needle voltage: 2500 V, orifice 1 temperature: 80 ° C, orifice 1 voltage: 60V, high-frequency ion-guided peak (ion-guide peak) voltage: 1000V, orifice 2 voltage: 5V

<hydroxyl value (OH valence) measurement conditions>

Acetic acid and pyridine were mixed at a weight ratio of 1:9 as an acetylation reagent. The sample was weighed into a flask, and an acetamidine reagent was added thereto, followed by heating at 80 ° C for 2 hours. After the reaction, phenolphthalein was used as an indicator and titrated with a 1 mol/l potassium hydroxide aqueous solution.

<NMR analysis>

As a result of the NMR analysis, the assignment of each peak is indicated by the number ((1) to (3)) of the following formula.

[Example 1] (Composition containing dipentaerythritol 3EO adduct acrylate) <Synthesis of dipentaerythritol 3EO adduct acrylate>

In the autoclave with a capacity of 1 liter equipped with a stirring device, dipentaerythritol (Koei Chemical Industry Co., Ltd.), OH price 1324 was fed. 254 g (1.0 mol), 127 g of toluene, 0.3 g of KOH, warmed to 90 ° C and stirred to obtain a slurry-like liquid. Next, by heating to 130 ° C, 176 g (4 mol) of ethylene oxide was slowly introduced into the autoclave to carry out a reaction. When ethylene oxide is introduced, the temperature inside the autoclave rises. The cooling is carried out at any time so that the reaction temperature is kept below 140 °C. After the reaction, the pressure was reduced to 140 mmHg or less at 140 ° C to remove excess ethylene oxide and a by-produced ethylene glycol polymer. Then, it was neutralized with acetic acid to adjust to pH 6-7. The OH value of the dipentaerythritol 3EO adduct obtained was 897.

The obtained ethylene glycol modified dipentaerythritol (OH price 897) 375 g (1 mol), acrylic acid 562 g (7.8 mol), p-toluenesulfonic acid 46 g, toluene 900 g, hydroquinone 0.9 g The mixture was fed to a glass four-necked flask, and a heating reaction was performed while blowing air. The water produced in the reaction is azeotroped with toluene and removed to the outside of the system at any time. The reaction temperature was between 100 and 110 ° C. At the end of the reaction, the amount of water removed to the outside of the system was 112 g. After the reaction, the mixture was washed with water and washed with water, and the toluene layer of the upper layer was separated, and toluene was distilled off under reduced pressure to obtain a 3 EO addition of dipentaerythritol represented by the general formulae (I) and (II). The acrylate was 615 g (yield 88%).

In this connection, the measurement of the valence of the hydroxyl group and the analysis of the hydroxyl group by ¹ H-NMR, ¹³ C-NMR, HPLC, and LC-MS, and the valence of the hydroxyl group are revealed to be dihydroxypentaerythritol containing a hydroxyl group. 3EO adduct acrylate. In the following, the results of NMR analysis and LC-MS analysis are shown, and the assignment of the peaks of NMR is shown by the above number.

< ¹³ C-NMR analysis of the 3EO adduct acrylate (400 MHz) in CDCl ₃ >

45ppm: from (2), 60ppm: from (3), 61~63ppm: (3) from the ethylene oxide addition, 68~73ppm: from the addition Ethylene oxide in (3), 77-79 ppm: derived from Deuterated chloroform, 128-131 ppm: derived from ester-bonded acrylic acid, 165-167 ppm: ester bond ( Esteratic site).

^<1 H-NMR analysis acrylate 3EO adduct (400MHz), in CDCl _3>

3.3~4.1ppm(16H): from (1), (3), 3.6~4.4ppm (8H): Ethylene oxide derived from OH added to (3), 5.7~6.4ppm(18H): Double bond derived from acrylate, 7.3 ppm: derived from deuterated chloroform.

<LC-MS Analysis of 3EO Additive Acrylate>

8.8~11.5 parts: ethylene oxide polymer diacrylate, 14~16 parts: dipentaerythritol ethylene oxide modified one acrylate, 16~20 parts: dipentaerythritol ethylene oxide modified Hexa acrylate.

<Preparation of Pigment Dispersion>

50 parts of titanium oxide ("Tipaque R-930" manufactured by Ishihara Sangyo Kaisha, Ltd.), pigment dispersant ["SOLSPERSE 32000" manufactured by The Lubrizol Co., Ltd.), N, N-diethyl propylene 45 parts of guanamine ("Kohjin Co., Ltd.") The mixture composed of DEAA" was kneading for 4 hours by using a ball mill to prepare a pigment dispersant liquid having a pigment concentration of 50% by weight.

<Preparation of ink composition containing pigment>

40 parts of the above pigment dispersant liquid, diphenyl (2,4,6-trimethyl benzhydryl) phosphine oxide (manufactured by Ciba Japan Co., Ltd.) Irgacure TPO"] 3 parts, diethyl oxysulfide 3 parts of "KAYACURE DETX-S" manufactured by Nippon Kayaku Co., Ltd., and 54 parts of the 3EO adduct acrylate obtained as described above, kneaded at 25 ° C using a ball mill 4 The ink composition for inkjet printing of the present invention is produced in an hour.

[Example 2] (Composition containing dipentaerythritol 4EO adduct acrylate) <Synthesis of dipentaerythritol 4EO adduct acrylate>

In a 1 liter autoclave equipped with a stirring device, dipentaerythritol (manufactured by Guangrong Chemical Industry Co., Ltd., OH price 1324), 254 g (1.0 mol), 127 g of toluene, and 0.3 g of KOH were fed. The temperature was raised to 90 ° C and stirred to obtain a slurry-like liquid. Next, by heating to 130 ° C, 220 g (5 mol) of ethylene oxide was slowly introduced into the autoclave to carry out a reaction. When ethylene oxide is introduced, the temperature inside the autoclave rises. Keep cold at any time However, the reaction temperature was kept below 140 °C. After the reaction, the pressure was reduced to 140 mmHg or less at 140 ° C to remove excess ethylene oxide and a by-produced ethylene glycol polymer. Then, it was neutralized with acetic acid to adjust to pH 6-7. The OH value of the dipentaerythritol 4EO adduct obtained was 765.

The obtained ethylene glycol modified dipentaerythritol (OH price 765) 440 g (1 mol), acrylic acid 562 g (7.8 m), p-toluenesulfonic acid 50 g, toluene 900 g, hydroquinone 1 g The mixture was fed to a glass four-necked flask, and a heating reaction was performed while blowing air. The water produced in the reaction is azeotroped with toluene and removed to the outside of the system at any time. The reaction temperature was from 100 to 110 ° C, and at the end of the reaction, the amount of reaction water removed to the outside of the system was 113 g. After the reaction, the mixture was washed with an alkali water and washed with water, and the toluene layer of the upper layer was separated, and toluene was distilled off under reduced pressure to obtain a dipentaerythritol 4EO adduct acrylate represented by the general formulae (I) and (II). 665 g (yield 87%).

In this connection, the measurement of the hydroxyl value and the analysis of ¹ H-NMR, ¹³ C-NMR, HPLC, and LC-MS, and the valence of a hydroxyl group show that it is a 4 EO addition of dipentaerythritol containing a hydroxyl group. Acrylate. In the following, the results of NMR analysis and LC-MS analysis are shown, and the assignment of the peaks of NMR is shown by the above number.

< ¹³ C-NMR analysis of <4EO adduct acrylate (400 MHz) in CDCl ₃ >

45ppm: from (2), 60ppm: from (3), 61~63ppm: (3), 68~73ppm derived from ethylene oxide addition: from ethylene oxide added to (3) 77~79ppm: derived from deuterated chloroform, 128~131ppm: derived from ester-bonded acrylic acid, 165~167ppm: ester bond.

^<1 H-NMR analysis 4EO acrylate adduct (400MHz), in CDCl _3>

3.3~4.1ppm(16H): from (1), (3), 3.6~4.4ppm (16H): Ethylene oxide derived from OH added to (3), 5.7~6.4ppm(18H): Double bond derived from acrylate, 7.3 ppm: derived from deuterated chloroform.

<LC-MS Analysis of 4EO Additive Acrylate>

8.8~11.5 parts: ethylene oxide polymer diacrylate, 14~16 parts: dipentaerythritol ethylene oxide modified one acrylate, 16~20 parts: dipentaerythritol ethylene oxide modified Hexa acrylate.

<Preparation of Pigment Dispersion and Modulation of Ink Composition Containing Pigment>

The same as in Example 1, except that the above 3EO adduct acrylate was used instead of the obtained 4EO adduct acrylate. The way to proceed.

[Example 3] (Composition containing dipentaerythritol 5EO adduct acrylate) <Synthesis of pentylenetetraol 5EO adduct acrylate>

In a 1 liter autoclave equipped with a stirring device, dipentaerythritol (manufactured by Guangrong Chemical Industry Co., Ltd., OH price 1324) 254 g (1.0 mol), distilled water 36 g, KOH 0.3 g was fed. The temperature was raised to 90 ° C and stirred to obtain a slurry-like liquid. Next, heating to 130 ° C, 264 g (6 mol) of ethylene oxide was slowly introduced into the autoclave to carry out a reaction. When ethylene oxide is introduced, the temperature inside the autoclave rises. Cool at any time to keep the reaction temperature below 140 °C. After the reaction, the pressure was reduced to 140 mmHg or less at 140 ° C to remove excess ethylene oxide and a by-produced ethylene glycol polymer. Then, it was neutralized with acetic acid to adjust to pH 6-7. The OH value of the obtained pentaerythritol 5EO adduct was 706.

The obtained ethylene glycol modified dipentaerythritol (OH 706) 477 g (1 mol), acrylic acid 562 g (7.8 mol), p-toluenesulfonic acid 52 g, toluene 900 g, hydroquinone 1 g The mixture was fed to a glass four-necked flask, and a heating reaction was performed while blowing air. The water produced in the reaction is azeotroped with toluene and removed to the outside of the system at any time. The reaction temperature is at 100~ At 110 ° C, at the end of the reaction, the amount of water removed to the outside of the system was 113 grams. After the reaction, the mixture was washed with an alkali water and washed with water, and the toluene layer of the upper layer was separated, and toluene was distilled off under reduced pressure to obtain a dipentaerythritol 5EO adduct acrylate represented by the general formulae (I) and (II). 697 g (yield 87%).

In this connection, the measurement of the hydroxyl value and the analysis by ¹ H-NMR, ¹³ C-NMR, HPLC, and LC-MS showed that it was a hydroxyl-containing dipentaerythritol 5EO adduct acrylate. . In the following, the results of NMR analysis, LC-MS analysis, and hydroxyl value measurement are shown, and the assignment of the peak of NMR is shown by the above number.

< ¹³ C-NMR analysis of the 5EO adduct acrylate (400 MHz) in CDCl ₃ >

45ppm: from (2), 60ppm: from (3), 61~63ppm: (3), 68~73ppm derived from ethylene oxide addition: from ethylene oxide added to (3) 77~79ppm: derived from deuterated chloroform, 128~131ppm: derived from ester-bonded acrylic acid, 165~167ppm: ester bond.

^<1 H-NMR analysis 5EO adduct acrylate (400MHz), in CDCl _3>

3.3~4.1ppm(16H): from (1), (3), 3.6~4.4ppm (24H): Ethylene oxide derived from OH added to (3), 5.7 to 6.4 ppm (18H): double bond derived from acrylate, 7.3 ppm: derived from deuterated chloroform.

<LC-MS Analysis of 5EO Additive Acrylate>

8.8~11.5 parts: ethylene oxide polymer diacrylate, 14~16 parts: dipentaerythritol ethylene oxide modified one acrylate, 16~20 parts: dipentaerythritol ethylene oxide modified Hexa acrylate.

<Preparation of Pigment Dispersion and Modulation of Ink Composition Containing Pigment>

The same procedure as in Example 1 was carried out except that the above-mentioned 3EO adduct acrylate was used instead of the obtained 5EO adduct acrylate.

[Comparative Example 1] (Composition containing dipentaerythritol-hexaacrylate)

Except that the above-mentioned dipentaerythritol 3EO adduct acrylate was used, and dipentaerythritol-hexaacrylate (KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd.) was used, the others were identical to Example 1. The way to proceed.

[Comparative Example 2] (Composition containing trimethylolpropane acrylate)

In addition to the above-mentioned dipentaerythritol 3EO adduct acrylate, trimethylolpropane acrylate (SARTOMER) was used. Except for SR351S (SARTOMER), the rest was carried out in exactly the same manner as in Example 1.

[Comparative Example 3] (Composition containing EO-modified trimethylolpropane triacrylate)

Except for the above-mentioned dipentaerythritol 3EO adduct acrylate, and ethylene oxide-modified trimethylolpropane triacrylate (SR454 manufactured by SARTOMER Co., Ltd.) was used, the others were identical to those of Example 1. Way to proceed.

[Comparative Example 4] (Composition containing caprolactone-modified dipentaerythritol acrylate)

In addition to the above-mentioned dipentaerythritol 3EO adduct acrylate, and the use of caprolactone-modified dipentaerythritol acrylate (KAYARAD DPCA-60 manufactured by Nippon Kayaku Co., Ltd.), Example 1 was carried out in exactly the same manner.

The evaluation of the ink compositions of the above Examples 1 to 3 and Comparative Examples 1 to 4 was carried out as follows.

[hardenability]

The ink compositions of Examples 1 to 3 and Comparative Examples 1 to 4 were adhered to an easy adhesion treatment PET film (Lumirror T-60 manufactured by Toray Industries, Inc.). The easy adhesion treatment surface was coated with a bar coater to have a dry film thickness of 10 μm. Moreover, in the Belt Conveyer Type UV irradiation device (GS-YUASA UV SYSTEM CSN2-40) and the Spot Type UV irradiation device (USHIO Optical Modulex SX-UID500H), the integrated illumination is 200mj/ Cm ² is hardened. In the case of ultraviolet ray irradiation, it was confirmed that the number of cells was set to be tack-free by shading with a Step Tablet (25 steps, manufactured by Riston Co., Ltd.). A high number of cells indicates a high degree of opacity. That is, even if it is hardened by a low exposure amount, it can be called that the ink composition has high photosensitivity and is excellent in productivity.

[steel wool resistance]

On the adhesive-treated PET film (Lumirror T-60, manufactured by Toray Industries, Inc.), a hardened film was produced in the same manner as the above evaluation of the hardenability. Further, the state of the coating film at the time of grinding 100 times using a steel wool of 00 L steel wool was observed by visual observation and evaluated on the following basis: ○: no scratch, Δ: confirmed in the test piece About 10 scratches, ×: Many scratches were confirmed.

[curl characteristics]

A hardened film was produced in the same manner as the above-described hardenability evaluation item on a PET film (Lumirror T-60, manufactured by Toray Industries, Inc.) which is easy to adhere. A point of the four corners of the film was fixed on a flat surface, and the heights of the remaining three points at the time of the film were measured, and the average value was taken as the curling property.

[spouting property]

The ejection property evaluation device ("inkjet drawing-coating device"; NanoPrinter-300 manufactured by MICROJET Corporation) was used for the evaluation of the discharge property. The evaluation device is a scanner that scans a head and scans by a plurality of nozzles of a piezoelectric element type. In addition, the atmospheric temperature of the measurement chamber was 25 °C.

○: No nozzle clogging, ×: No nozzle clogging.

As is apparent from the results shown in Table 1, in the case of the ink compositions of Examples 1 to 3 of the present invention, the discharge can be improved as compared with Comparative Example 1 using dipentaerythritol-hexaacrylate. Sex. It can be considered that the crosslinking of the crosslinkable monomer itself is reduced by moderate modification of ethylene oxide. In addition, although specific data is not shown, even when compared with the same acrylate (dipentaerythritol 12EO adduct acrylate) obtained by adding 12 moles of ethylene oxide to diheptaerythritol, spouting property Great improvements have been made. In addition, a considerable improvement was obtained as compared with the acrylate (dipentaerythritol 8EO adduct acrylate) which was formed by adding 8 moles of ethylene oxide to dipentaerythritol.

In the case of the comparative examples 2 to 4, the use of a crosslinkable (polyfunctional) monomer which is low in viscosity and excellent in discharge property, although the discharge property and the curling property are good, the hardenability and the steel wool resistance are low. . In the case of the ink composition of the examples of the present application, it is known that the steel wool can be maintained while controlling the molar amount of ethylene oxide to the minimum necessary amount. Sexuality suppresses deformation of the printed matter caused by hardening shrinkage of the ink composition on the printed matter. Further, the hardenability was also greatly improved as compared with Comparative Example 1 using dipentaerythritol-hexaacrylate. The improvement in the hardenability is considered to be due to the modification of ethylene oxide, which improves the mobility and degree of freedom of the terminal acrylonitrile group. In addition, although not shown specifically Hardening and steel wool resistance compared to acrylate (dipentaerythritol 12EO adduct acrylate) which is the same as dipentyl alcohol plus 12 moles of ethylene oxide. It has also been greatly improved. In addition, a considerable improvement was obtained as compared with the acrylate (dipentaerythritol 8EO adduct acrylate) which was formed by adding 8 moles of ethylene oxide to dipentaerythritol.

[Industrial use possibility]

As described above, there is an alkylene oxide-modified (meth)acrylic acid which is obtained by optimizing the molar number of alkylene oxide (AO) represented by the above formulas (I) and (II). The pentaerythritol ester as the crosslinkable monomer of the ink composition for inkjet printing of the present invention exhibits low viscosity, good photosensitivity and hardenability, and low shrinkage, and hardenability. The material has good resistance to friction and firmness. Therefore, it is suitable for use as an ink composition for inkjet printing which is required to be printed or coated, such as water resistance, fastness, and the like. Further, in particular, it can be applied to the manufacture of a circuit product such as a printed wiring board, for example, formation of an insulating film at a specific place after wiring formation, or vapor deposition. Formation of a photoresist pattern such as sputtering.

The present invention has been described in detail with reference to the specific embodiments thereof, and it is obvious to those skilled in the art that various changes or modifications can be made without departing from the spirit and scope of the invention.

The present application is based on Japanese Patent Application No. 2013-040861, filed on Jan.

Claims (2)

An ink composition for inkjet printing comprising an alkylene oxide-modified (methylene) acrylate (methylene) acrylate having a structure represented by the following general formulae (I) and (II), Wherein, in the formula (I), R represents a substituent represented by the formula (II), and AO represents a group selected from -CH ₂ CH ₂ O-, -CH ₂ CH(CH ₃ )O-, -CH One or more of ₂ alkylene oxide units represented by ₂ CH ₂ CH ₂ CH ₂ O- or -CH ₂ CH(C ₂ H ₅ )O-, indicating the average degree of polymerization of the added alkylene oxide chain L is 0 < L ≦ 5, the average value of m is greater than 0 and 5 or less, and the average addition molar number of the alkylene oxide L × m is 0 < L × m ≦ 5, n is 1 or 2, o The average value is 0 or more and 6 or less, and the total value of m, n, and o is 6; in the general formula (II), R ² represents a hydrogen atom or a methyl group. An ink composition for inkjet printing according to claim 1, wherein The average addition mole number (L x m) of pentaerythritol per 1 mole of alkylene oxide is 3 to 5.