JP7425971B2 - inkjet printing ink - Google Patents

Description

The present invention relates to inkjet printing inks.

Color filters used in color display devices generally have pixels of three colors: red (R), green (G), and blue (B), and these pixels form a grid-like black light-shielding layer called a black matrix. surrounded by As one method for manufacturing such a color filter, a method has been proposed in which a colored layer of a color filter is formed by an inkjet method using a black matrix as a partition (for example, Patent Documents 1 and 2). In various display devices as well as color filters, image contrast may be improved by providing a black matrix on the boundary between each pixel. The black matrix is formed, for example, by a photolithographic method using a photosensitive resin composition containing a black pigment. Carbon black is commonly used as a black pigment.

In recent years, black matrices are required to have higher optical density (hereinafter sometimes referred to as "OD value").

International Publication 2018/155500 Japanese Patent Application Publication No. 2004-325736

Producing the black matrix by the inkjet method is advantageous in terms of simplifying the manufacturing process, reducing environmental impact, and reducing the amount of raw materials used. It is expected that the raw material usage fee for the inkjet method can be reduced to 90% or less compared to the raw material usage fee when using a photosensitive resin composition. However, when printing with ink on the surface of a non-absorbing material such as a glass substrate using the inkjet method, unlike printing on paper or cloth that absorbs ink, the cured film that is formed when the ink hardens and the base material. Adhesion to the material was sometimes insufficient after the durability test. Cured films formed with inks containing a large amount of colorants such as pigments to increase the OD value tended to exhibit particularly low adhesion.

An object of one aspect of the present invention is to provide an inkjet printing ink that can form a cured film that maintains high adhesion to the surface of a non-absorbent adherend even after a durability test.

The inkjet printing ink according to one aspect of the present invention includes (A) a binder polymer, (B) a blocked isocyanate, (C) an epoxy resin, (D) a coloring agent, and (E) a silane coupling agent. (F) a solvent. The binder polymer has carboxyl groups. When the total amount of the binder polymer, the block isocyanate, and the epoxy resin is 100 parts by mass, the content of the binder polymer is 60 to 80 parts by mass, and the content of the block isocyanate is 10 to 35 parts by mass. , the content of the epoxy resin is 5 to 30 parts by mass.

According to one aspect of the present invention, an inkjet printing ink capable of forming a cured film that maintains high adhesion to the surface of a non-absorbent adherend even after a durability test is provided. The cured film formed by the ink according to one aspect of the present invention can maintain high adhesion to the surface of a non-absorbent substrate after a hot water bath test.

Inkjet printing inks according to some embodiments of the present invention can have good ejection properties that can suppress clogging of inkjet nozzles.

A cured film formed from the ink according to one aspect of the present invention can be used, for example, as a light shielding film for shielding excess light from a backlight or the like.

Hereinafter, several embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

As used herein, "(meth)acrylic acid" means "acrylic acid" or "methacrylic acid", "(meth)acrylate" means "acrylate" or "methacrylate", and "(meth)acrylate" means "acrylate" or "methacrylate"; "meth)acryloyl group" means "acryloyl group" or "methacryloyl group".

The inkjet printing ink according to one embodiment includes (A) a binder polymer, (B) a blocked isocyanate, (C) an epoxy resin, (D) a colorant, (E) a silane coupling agent, and (F ) Contains a solvent.

Component (A): Binder polymer having carboxyl groups The binder polymer of component (A) is a polymer having carboxyl groups. Examples of binder polymers include acrylic polymers, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, phenolic resins, and urethane resins. These can be used alone or in combination of two or more. From the viewpoint of adhesion to the adherend, the binder polymer may be an acrylic polymer.

The acrylic polymer as component (A) is a polymer mainly composed of monomer units derived from a monomer having a (meth)acryloyl group. The acrylic polymer may be a copolymer of a monomer having a carboxyl group and another monomer.

Examples of monomers having a (meth)acryloyl group include (meth)acrylic acid; (meth)acrylic acid alkyl ester, (meth)acrylic acid glycidyl ester, β-furyl (meth)acrylic acid, and β-styryl. Examples include (meth)acrylic acid derivatives such as (meth)acrylic acid; and acrylamide. The acrylic polymer may contain one or more monomers selected from these as monomer units. Among these monomers, (meth)acrylic acid, β-furyl (meth)acrylic acid, and β-styryl (meth)acrylic acid are monomers having carboxyl groups, and monomer units derived from these monomers The acrylic polymer containing can have a carboxyl group. The monomer having a carboxyl group may be (meth)acrylic acid.

Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, and (meth)acrylate. Examples include hexyl acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and structural isomers thereof. The acrylic polymer may contain at least one selected from methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate as a monomer unit.

Examples of other monomers include styrene; styrene derivatives such as α-methylstyrene, p-methylstyrene, and p-ethylstyrene; acrylonitrile; esters of vinyl alcohol such as vinyl-n-butyl ether; maleic acid, maleic Acid monoesters; and organic carboxylic acids having a polymerizable unsaturated group such as fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. Among these, acrylic polymers containing monomer units derived from organic carboxylic acids can have carboxyl groups.

The acrylic polymer may be a copolymer having (meth)acrylic acid and (meth)acrylic acid ester having a hydroxyl group as monomer units, and (meth)acrylic acid, alkyl (meth)acrylate It may also be a copolymer having as a monomer unit an ester and a (meth)acrylic acid ester having a hydroxyl group.

Examples of (meth)acrylic esters containing hydroxyl groups include hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and hydroxybutyl (meth)acrylate. ) hydroxypentyl acrylate, hydroxyhexyl (meth)acrylate, hydroxyheptyl (meth)acrylate, hydroxyoctyl (meth)acrylate, and structural isomers thereof.

The acid value of the binder polymer having a carboxyl group may be 20 mgKOH/g or more, 40 mgKOH/g or more, or 60 mgKOH/g or more from the viewpoint of ink curability and adhesion. In terms of excellent adhesion, the acid value of the binder polymer may be 250 mgKOH/g or less, 240 mgKOH/g or less, 230 mgKOH/g or less, or 220 mgKOH/g or less.

Here, the acid value can be measured by the following method.
First, approximately 1 g of a polymer solution containing a binder polymer whose acid value is to be measured is accurately weighed. Thereafter, 30 g of acetone is added to this polymer solution and mixed uniformly. An appropriate amount of phenolphthalein as an indicator is added to the mixed solution. Titration is performed using a 0.1N KOH aqueous solution. The titer of the KOH aqueous solution is determined, and the acid value is calculated using the following formula.
A=10×Vf×56.1/(Wp×I)
In the formula, A indicates the acid value (mgKOH/g), Vf indicates the titration amount (mL) of 0.1N KOH aqueous solution, Wp indicates the mass (g) of the measured polymer solution, and I indicates the measured mass (g) of the polymer solution. The percentage (% by mass) of non-volatile content (binder polymer) in the polymer solution is shown.

The weight average molecular weight of the binder polymer may be 15,000 or more, or 18,000 or more from the viewpoint of excellent physical properties of the cured film. From the viewpoint of good ejection properties from an inkjet nozzle, the weight average molecular weight of the binder polymer may be 30,000 or less, or 22,000 or less. The weight average molecular weight herein means a value measured by gel permeation chromatography and converted to standard polystyrene.

The content of the binder polymer may be 60 to 80 parts by weight based on 100 parts by weight of the total amount of the binder polymer, block isocyanate, and epoxy resin. From the viewpoint of adhesion and ink ejectability, the content of the binder polymer may be 60 to 70 parts by mass based on 100 parts by mass of the total amount of the binder polymer, block isocyanate, and epoxy resin.

(B) Blocked Isocyanate Blocked isocyanate is a compound formed from an isocyanate compound and a blocking agent, and has two or more isocyanate groups blocked by the blocking agent. Since the blocking agent dissociates upon heating and the isocyanate group is regenerated, the blocked isocyanate has a long pot life and the ink containing it has excellent processability. In the ink according to this embodiment, blocked isocyanate is used as a curing agent. Blocked isocyanate is usually heated at a relatively low temperature to dissociate (deprotect) the blocking agent and regenerate the isocyanate group. The reaction between the regenerated isocyanate groups and the carboxyl groups of the binder polymer contributes to the curing of the ink.

Blocking agents can be selected from those commonly used in the art. Examples of blocking agents include phenolic blocking agents such as phenol, cresol, xylenol, chlorophenol, and ethylphenol; lactam blocking agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam; Active methylene blocking agents such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, and acetylacetone; methanol, ethanol, propanol, butanol, amyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl Alcohol blocking agents such as ether, propylene glycol monomethyl ether, benzyl alcohol, methyl glycolate, butyl glycolate, diacetone alcohol, methyl lactate and ethyl lactate; formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monoxime , cyclohexanone oxime, and other oxime-based blocking agents; mercaptan-based blocking agents such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, thiophenol, methylthiophenol, and ethylthiophenol; acid amide-based blocking agents such as acetate amide and benzamide; amber Examples include imide blocking agents such as acid imide and maleic acid imide; imidazole blocking agents such as imidazole and 2-ethylimidazole; pyrazole blocking agents; and triazole blocking agents. For low temperature curing, active methylene blocking agents and oxime blocking agents are advantageous. The blocking agent may be at least one oxime-based blocking agent selected from methyl ethyl ketoxime, acetaldehyde oxime, and cyclohexanone oxime.

The isocyanate compound forming the blocked isocyanate may be a diisocyanate compound, examples thereof include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4' -diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3 '-Dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3 , 3'-dimethoxydiphenyl-4,4'-diisocyanate; xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, xylylene-1,2-diisocyanate, tetramethylxylylene diisocyanate, etc. Aroaliphatic diisocyanates: aliphatic diisocyanates such as hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, lysine diisocyanate: isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate and alicyclic diisocyanates such as hydrogenated tetramethylxylene diisocyanate.

The blocked isocyanate may be an isocyanurate-type blocked isocyanate having an isocyanurate group or a biuret-type blocked isocyanate. The isocyanurate-type blocked isocyanate is a compound formed from an isocyanurate-type isocyanate derived from a diisocyanate compound and a blocking agent. A biuret-type blocked isocyanate is a compound formed from a biuret-type blocked isocyanate derived from a diisocyanate compound and a blocking agent. The blocking agent forming the isocyanurate-type blocked isocyanate or the biuret-type blocked isocyanate may be at least one selected from methyl ethyl ketoxime, acetaldehyde oxime, and cyclohexanone oxime. The diisocyanate compound from which the isocyanurate-type blocked isocyanate is derived may be hexamethylene diisocyanate. Isocyanurate-type isocyanates derived by trimerization (isocyanuration) of hexamethylene diisocyanate are sometimes referred to as isocyanurate-modified hexamethylene diisocyanates.

The isocyanurate reaction that produces isocyanurate-type isocyanates from diisocyanate compounds can be carried out using, for example, isocyanurate catalysts such as tertiary amines, alkyl-substituted ethyleneimines, trialkylphosphines, acetylacetone metal salts, and metals of various organic acids. Salts etc. are used alone or in combination. A co-catalyst such as a phenolic hydroxyl group-containing compound or an alcoholic hydroxyl group-containing compound is used as necessary. The reaction temperature is usually 0 to 90°C. The reaction is carried out in the absence or presence of a solvent or in a polyol or plasticizer such as dioctyl phthalate (DOP) which is liquid at the reaction temperature. Examples of solvents include aromatic solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and butyl acetate, propylene glycol methyl ether acetate, diethylene glycol butyl ether acetate, and ethyl-3-ethoxypropylene. It is carried out in the presence of a glycol ether ester system such as pionate and optionally in a liquid polyol or a plasticizer such as dioctyl phthalate (DOP) at the reaction temperature. After the reaction, the catalyst can be inactivated and the reaction can be stopped by using a terminator (for example, phosphoric acid, para-toluenesulfonic acid ester, sulfur). Thereafter, odor can be suppressed by removing free isocyanate monomers.

Isocyanurate-modified hexamethylene diisocyanate is a compound containing two or more isocyanate groups in one molecule. Isocyanurate-modified hexamethylene diisocyanate is, for example, Duranate TPA-100, TKA-100, MFA-75B, MHG-80B, TUL-100, TLA-100, TSA-100, TSS-100, or TSE manufactured by Asahi Kasei Corporation. -100 commercially available.

The content of the block isocyanate may be 10 to 35 parts by weight based on 100 parts by weight of the total amount of the binder polymer, block isocyanate, and epoxy resin.

(C) Epoxy resin Epoxy resin is usually a compound having two or more epoxy groups. Examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenol type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, phenol compound ( Glycidyl etherified products of condensates of phenol, cresol, alkylphenols, catechol, bisphenol F, bisphenol A, bisphenol S, etc.) and aldehyde compounds (formaldehyde, salicylaldehyde, etc.), glycidyl etherified products of difunctional phenols, glycidyl difunctional alcohols Examples include etherified products, glycidyl etherified products of trifunctional or higher functional polyphenols, and hydrogenated products or halogenated products thereof. From the viewpoint of adhesion to the adherend, the epoxy resin may be a compound containing an alicyclic ring or an aromatic ring, and in particular may be a compound having a dicyclopentadiene skeleton, which is an alicyclic ring. Examples of epoxy resins having a dicyclopentadiene skeleton include dimethylol tricyclodecane diglycidyl ether and polyglycidyl ether of a polycondensate of cresol and dicyclopentadiene.

The content of the epoxy resin may be 5 to 30 parts by weight based on 100 parts by weight of the total amount of the binder polymer, block isocyanate, and epoxy resin. From the viewpoint of adhesion and ink ejectability, the content of the epoxy resin may be 10 to 20 parts by mass based on 100 parts by mass of the total amount of the binder polymer, block isocyanate, and epoxy resin.

(D) Colorant The colorant contained in the ink may be appropriately selected from various colorants depending on the purpose and the like. Colorants of various colors such as yellow, cyan, magenta, and black can be employed. The colorant may be a pigment such as an organic pigment or an inorganic pigment that disperses well in the ink and has excellent light resistance.

Specific examples of organic pigments include dye lake pigments, azo-based, benzimidazolone-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigo-based, thioindico-based, perylene-based, perinone-based, diketopyrrolopyrrole-based, Examples include isoindolinone-based, nitro-based, nitroso-based, anthraquinone-based, flavanthrone-based, quinophthalone-based, pyranthrone-based, and indanthrone-based pigments. Specific examples of inorganic pigments include carbon black, titanium oxide, red iron oxide, graphite, iron black, chromium oxide green, and aluminum hydroxide.

The pigment exists in the form of fine particles dispersed in the solvent of component (F), and if it aggregates, it can cause nozzle clogging. From the viewpoint of preventing clogging, the average particle size of the pigment may be 10 to 300 nm, 10 to 250 nm, or 10 to 200 nm.

Carbon black can be used as a pigment (coloring material) that imparts light-shielding properties to a light-shielding cured film used as a black matrix or the like. Examples of commercially available carbon blacks include carbon black #2400, #2350, #2300, #2200, #1000, #980, #970, #960, #950, #900, #850 manufactured by Mitsubishi Chemical Corporation. , MCF88, #650, MA600, MA7, MA8, MA11, MA100, MA220, IL30B, IL31B, IL7B, IL11B, IL52B, #4000, #4010, #55, #52, #50, #47, #45, # 44, #40, #33, #32, #30, #20, #10, #5, CF9, #3050, #3150, #3250, #3750, #3950, Diamond Black A, Diamond Black N220M, Diamond Black N234, Diamond Black I, Diamond Black LI, Diamond Black II, Diamond Black 339, Diamond Black SH, Diamond Black SHA, Diamond Black LH, Diamond Black H, Diamond Black HA, Diamond Black SF, Diamond Black N550M, Diamond Black E, Dia Black G, Dia Black R, Dia Black N760M, Dia Black LR; Carbon black Thermax N990, N991, N907, N908, N990, N991, N908 manufactured by Can Carb; Carbon black Asahi #80 manufactured by Asahi Carbon Co., Ltd. , Asahi #70, Asahi #70L, Asahi F-200, Asahi #66, Asahi #66HN, Asahi #60H, Asahi #60U, Asahi #60, Asahi #55, Asahi #50H, Asahi #51, Asahi #50U, Asahi #50, Asahi #35, Asahi #15, Asahi Thermal; Degussa carbon black ColorBlackFw200, ColorBlack Fw2, ColorBlack Fw2V, ColorBlack Fw1, ColorBlackFw18, ColorBlackS1 70, ColorBlackS160, SpecialBlack6, SpecialBlack5, SpecialBlack4, SpecialBlack4A, PrintexU, PrintexV, Printex 140U, Printex 140V; SF BLACK AD2065, SF BLACK AD2091, SF BLACK AD2128, SF BLACK AH4203 manufactured by Sanyo Shiki Co., Ltd., and the like.

As a light-shielding material, an inorganic pigment may be combined with an organic pigment as an auxiliary pigment. By selecting an organic pigment that exhibits a complementary color to the inorganic pigment, the following effects can be obtained. For example, carbon black exhibits a reddish black color. Therefore, by adding an organic pigment that exhibits blue, which is the complementary color of red, to carbon black as an auxiliary pigment, the redness of carbon black disappears, and the cured film (light-shielding layer) can exhibit a higher quality black color as a whole. .

Since these pigments often have aggregated particles, dispersion treatment may be required before use. A mill base is prepared by adding a dispersant and a solvent to the pigment, and the pigment can be dispersed using a ball mill, a sand mill, a bead mill, a three-roll mill, a paint shaker, an ultrasonic wave, a bubble homogenizer, or the like. It is also possible to combine two or more of these processing methods. As the dispersant, resins or other known dispersants can be used.

The content of the colorant (especially pigment) may be 25 to 60% by mass based on the mass of the total solid content (components other than the solvent) of the ink. When the content of the colorant (or pigment) is 25% by mass or more, it is easy to form a cured film having a high optical density (OD value) required for a black matrix or the like. When the optical density is high, effects such as reducing light leakage and improving contrast in a display device can be obtained. When the content of the colorant (or pigment) is 60% by mass or less, the adhesion to the adherend tends to be further improved.

(E) Silane coupling agent When the inkjet printing ink contains a silane coupling agent, the adhesion of the cured film to the adherend (substrate) is further improved. The silane coupling agent may be, for example, an alkylsilane, an alkoxysilane, a vinylsilane, an epoxysilane, an aminosilane, an acryloylsilane, a methacryloylsilane, a mercaptosilane, a sulfidesilane, an isocyanatesilane, a sulfursilane, a styrylsilane, or an alkylchlorosilane. .

Specific examples of silane coupling agents include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, diisopropyldimethoxysilane, isobutyl Trimethoxysilane, diisobutyldimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-dodecylmethoxysilane, phenyltrimethoxysilane, Diphenyldimethoxysilane, triphenylsilanol, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, n-octyldimethylchlorosilane, tetraethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2- Aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropylmethyldimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxy Silane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, bis(3-(triethoxysilyl)propyl)disulfide, bis(3-(triethoxysilyl)propyl)tetrasulfide, Vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, allyltrimethoxysilane, diallyldimethylsilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3- Methacryloyloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, N-(1,3-dimethylbutylidene)-3-aminopropyltriethoxysilane , aminosilane. These can be used alone or in combination of two or more.

The silane coupling agent may have an epoxy group. The silane coupling agent having an epoxy group has a greater interaction with the binder polymer, and more effectively develops the adhesiveness of the cured film to the adherend (substrate). Here, the number of epoxy groups that the silane coupling agent has is usually one. In this specification, compounds having two or more epoxy groups are classified as the above-mentioned epoxy resins.

Examples of silane coupling agents having epoxy groups include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyl Examples include diethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

The content of the silane coupling agent may be 0 to 10% by mass based on the mass of the ink. This tends to further improve the adhesion of the cured film formed by the ink to the adherend (support).

(Leveling agent)
When the inkjet printing ink contains a pigment as a colorant, it may contain a leveling agent to improve the smoothness of the cured film. The leveling agent can be selected without particular limitation from those commonly used in the field of inks, and may be a siloxane compound.

Examples of leveling agents include BYK-300, 302, 306, 307, 310, 313, 315N, 320, 322, 323, 325N, 326, 327, 330, 331, 333, 342 manufactured by BYK Chemie Japan Co., Ltd. 345/346, 347, 348, 349, 370, 375, 377, 378, 3450, 3451, 3455, 3456, 3760, 350, 354, 355/356, 358N/361N, 381, 392, 394, 3441, 399, 3440, 3550, 3560, 3565, and 3566. These may be used alone or in combination of two or more.

(F) Solvent In the inkjet printing ink according to the present embodiment, the content of the solvent (F) component may be 60 to 95% by mass based on the mass of the ink. When the content of the solvent is 60% by mass or more, particularly good inkjet ejection properties tend to be easily obtained. When the content of the solvent is 95% by mass or less, a cured film having a sufficiently dark color tends to be easily formed.

Examples of solvents include glycol ethers (ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether, etc.), ketones (acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-propyl ketone, methyl-n-butyl ketone, methyl -iso-butyl ketone, methyl-n-pentyl ketone, methyl-n-hexyl ketone, diethyl ketone, dipropyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, γ-valerolactone, cyclohexanone, etc.), esters (ethyl acetate, butyl acetate, ethylene glycol alkyl ether acetate, propylene glycol alkyl ether acetate, etc.), cyclic esters (gamma-butyrolactone, etc.), aromatic hydrocarbons (toluene, xylene, mesitylene, limonene, etc.), alcohols (methanol, ethanol, normal propanol, isopropanol, butanol, geraniol, linalool, citronellol, etc.), and ethers (tetrahydrofuran, 1,8-cineol, etc.). These may be used alone or in combination of two or more.

The solvent may contain as a main component at least one selected from acetate ester (acetate ester solvent), glycol ether (glycol ether solvent), and glycol ester (glycol ester solvent). Here, the main component usually means a component that accounts for 50% by mass or more of the total amount of the solvent.

Examples of acetic acid esters include methyl acetate, ethyl acetate, propyl acetate, iso-propyl acetate, butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, Methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, nonyl acetate, methyl acetoacetate and ethyl acetoacetate.

Examples of glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol. Glycol monoalkyl ethers such as monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-propyl ether, ethylene glycol dimethyl ether; Butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl mono-n-propyl ether, diethylene glycol methyl mono-n-butyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, diethylene glycol methyl mono- n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl mono-n-butyl ether, triethylene glycol di-n-butyl ether, triethylene glycol methyl mono-n- Hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetradiethylene glycol methyl ethyl ether, tetraethylene glycol methyl mono-n-butyl ether, diethylene glycol di-n-butyl ether, tetraethylene glycol methyl mono-n-hexyl ether, tetraethylene Glycol di-n-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether, dipropylene Glycol methyl mono-n-butyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl mono-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, Propylene glycol methyl ethyl ether, tripropylene glycol methyl mono-n-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl mono-n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetradipropylene Examples include alkylene glycol dialkyl ethers such as glycol methyl ethyl ether, tetrapropylene glycol methyl mono-n-butyl ether, tetrapropylene glycol methyl mono-n-hexyl ether, and tetrapropylene glycol di-n-butyl ether.

Examples of glycol esters include ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol-n-butyl ether. Acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol ethyl ether acetate, and other alkylene glycol alkyl ether acetates.

A cured film used as a light-shielding film etc. is produced by, for example, a process of forming an ink film forming a pattern such as a grid on a base material by inkjet printing using ink, and a process of heating the ink film to form a cured film. It can be formed by a method including forming.

Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the present invention is not limited to the following examples.

1. Raw material (A) Binder polymer acrylic polymer A1
80 parts by mass of propylene glycol monomethyl ether acetate (PMA) was placed in a flask equipped with a stirrer, a reflux condenser, an inert gas inlet, and a thermometer. The temperature of PMA in the flask was raised to 145° C. under a nitrogen gas atmosphere. 17 parts by mass of methacrylic acid, 53 parts by mass of methyl methacrylate, 20 parts by mass of ethyl acrylate, 0.7 parts by mass of 2,2'-azobis(isobutyronitrile), and 11 parts by mass of PMA. The mixed liquid was uniformly added dropwise over 2.5 hours while maintaining the temperature of the liquid in the flask at 145°C±2°C. After the dropwise addition, stirring was continued for 3.5 hours while maintaining the temperature at 145°C±2°C to obtain a solution containing the acrylic polymer A1 having carboxyl groups. The concentration of acrylic polymer A1 was 50% by mass. Table 1 shows the weight average molecular weight of acrylic polymer A1.

Acrylic polymers A2, A3 and A4
Acrylic polymer A2 having a carboxyl group was synthesized in the same manner as in the synthesis of acrylic polymer A1, except that the type and amount of monomer, radical polymerization initiator, propylene glycol monomethyl ether acetate, and reaction temperature were changed as shown in Table 1. , A3 and A4 solutions were obtained. The concentration of the solutions of acrylic polymers A2 and A4 was 50% by mass, and the concentration of the solution of acrylic polymer A3 was 30% by mass.

(B) Blocked isocyanate/isocyanurate type blocked isocyanate (BL3175, manufactured by Sumika Covestro Urethane Co., Ltd.)
(C) Epoxy resin
・Epoxy compound containing dicyclopentadiene skeleton (EP-4088L, manufactured by ADEKA Co., Ltd.)
(D) Pigment/SF BLACK AH4203: Carbon black composition (carbon black content: 20-30% by mass, manufactured by Sanyo Shiki Co., Ltd.)
(E) Silane coupling agent KBM-403: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)
(Leveling agent)
・BYK-333: Mixture of polyether-modified polydimethylsiloxane and polyether (manufactured by BYK-Chemie Japan Co., Ltd.)
(F) Solvent - Gamma-butyrolactone (GBL): Manufactured by Mitsubishi Chemical Corporation - Propylene glycol monomethyl ether acetate (PMA): Manufactured by KH Neochem Corporation

2. Ink raw materials were mixed in the ratios (parts by mass) shown in Table 2. The mixture was stirred for 15 minutes to obtain inks of Examples and Comparative Examples for forming cured films. The amount of each component is the amount (parts by mass) of the component (solid content) excluding the solvent contained in each material. "Solvent derived from raw materials" in the table indicates the total amount of solvent contained in each component before mixing.

3. Preparation of cured film A soda lime glass plate (100 mm x 150 mm, thickness 2 mm) was prepared as a base material. The surface of the substrate was wiped with an acetone-soaked cloth and then allowed to air dry. Each ink was uniformly applied onto the substrate using a barcoder. The coating film was temporarily dried by heating in a hot air convection dryer at 80° C. for 15 minutes to remove the solvent. The temporarily dried coating film was thermally cured by heating for 60 minutes in a hot air convection dryer at 200° C. to obtain a test piece for evaluation having a cured film (cured coating film, thickness 5 μm).

4. Evaluation 4-1. Viscosity of Ink The viscosity of the ink was measured using a viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80L viscometer, measurement temperature 25° C., rotation speed 20 rpm). Based on the viscosity measurement results, evaluation was made according to the following criteria. From the viewpoint of inkjet ejection properties, it means that the viscosity is better in the order of A, B, C, D, and E.
A: Viscosity 8.5mPa or more and 9.5mPas or less B: Viscosity 8.0mPa or more and less than 8.5mPas, or more than 9.5mPas and 10.0mPas or less C: Viscosity 7.5mPa - s or more and less than 8.0 mPa-s, or more than 10.0 mPa-s and less than 10.5 mPa-s D: Viscosity 7.0 mPa-s or more and less than 7.5 mPa-s, or more than 10.5 mPa-s and 11.0 mPa-s s or less E: Viscosity less than 7.0 mPa・s or more than 11.0 mPa・s

4-2. Cross-cut test (adhesion)
(initial)
A 100-square cross-cut test was conducted with reference to the JIS standard (K5400: Paint general test method [K5600]). A cross-cut cut of 1×1 mm square was made in the cured film of the evaluation test piece using a cutter knife. Mending tape (CT-18, manufactured by Nichiban Co., Ltd.) was firmly pressed onto the grid portion of the cured film. The mending tape was slowly peeled off from the cured film by pulling the end of the mending tape at an angle of approximately 0°. Thereafter, the area ratio of the area of the portion remaining in close contact with the base material to the total area of the grid portion was measured. Adhesion was evaluated according to the following criteria. It means that the adhesion is good in the order of A, B, C, D, E, and F.
A: Area ratio 100%
B: Area ratio of 95% or more and less than 100% C: Area ratio of 85% or more and less than 95% D: Area ratio of 65% or more and less than 85% E: Area ratio of 35% or more and less than 65% F: Area ratio of 0% or more and less than 35%

(Hot water bath test)
The test piece for evaluation was left in pure water at 85°C for 6 hours. The test piece for evaluation was taken out from the pure water and thoroughly wiped. Thereafter, the adhesion of the cured film was evaluated by the same cross-cut test as above.

Table 2 shows the evaluation results. The cured films formed from the inks of Examples 1 to 9 showed excellent adhesion initially and after the hot water bath test. With respect to 100 parts by mass of the total amount of the binder polymer, block isocyanate, and epoxy resin, the content of the binder polymer is 60 to 70 parts by mass, the content of the block isocyanate is 10 to 35 parts by mass, and the content of the epoxy resin is The inks of Examples 1, 2, and 5 to 9 containing 10 to 20 parts by mass exhibited particularly excellent properties in terms of adhesion after the hot water bath test and viscosity suitable for dischargeability.

Claims (9)

(A) a binder polymer;
(B) blocked isocyanate;
(C) an epoxy resin;
(D) a coloring agent;
(E) a silane coupling agent;
(F) a solvent;
Contains
the binder polymer has a carboxyl group,
When the total amount of the binder polymer, the block isocyanate, and the epoxy resin is 100 parts by mass, the content of the binder polymer is 60 to 80 parts by mass, and the content of the block isocyanate is 10 to 35 parts by mass. , the content of the epoxy resin is 5 to 30 parts by mass,
Ink for inkjet printing. The inkjet printing ink according to claim 1, wherein the blocked isocyanate includes an isocyanurate-type blocked isocyanate formed from an isocyanurate-type isocyanate derived from a diisocyanate compound and a blocking agent. The inkjet printing ink according to claim 1, wherein the blocked isocyanate includes an isocyanurate-type blocked isocyanate formed from an isocyanurate-type isocyanate derived from hexamethylene diisocyanate and a blocking agent. Inkjet printing according to any one of claims 1 to 3, wherein the blocked isocyanate contains a compound having an isocyanate group blocked with at least one blocking agent selected from methyl ethyl ketoxime, acetaldehyde oxime, and cyclohexanone oxime. ink. The inkjet printing ink according to any one of claims 1 to 4, wherein the epoxy resin contains a compound having an alicyclic ring or an aromatic ring. The inkjet printing ink according to any one of claims 1 to 4, wherein the epoxy resin contains a compound having a dicyclopentadiene skeleton. The inkjet printing ink according to any one of claims 1 to 6, wherein the colorant contains a pigment with an average particle size of 10 to 300 nm. The inkjet printing ink according to any one of claims 1 to 7, wherein the silane coupling agent contains a compound having an epoxy group. The inkjet printing ink according to any one of claims 1 to 8, wherein the solvent contains at least one selected from the group consisting of glycol ether, glycol ester, and cyclic ester.