JP4831266B2 - Ink composition for letterpress reversal printing, printed matter, and color filter - Google Patents

Description

  The present invention relates to a printing ink composition used in a letterpress reverse printing method and a color filter produced by a letterpress reverse printing method using the printing ink composition.

  In recent years, in order to cope with cost reduction and miniaturization of electronic parts, various circuit boards, liquid crystal display elements, organic electroluminescence elements, organic thin film solar cells, conductive layers for electronic parts such as thin film transistors, insulating layers, semiconductor layers, Attempts have been made to form pattern shapes such as a light shielding layer, a black matrix of a color filter, and a light shielding design layer around the display by a printing method, an ink jet, or the like. Of these, the printing method is attracting attention as an inexpensive manufacturing method compared to the current photoresist method, but there is room for improvement in the printability of blankets, producing patterns with fine pattern dimensions and good shapes. It was difficult to do.

On the other hand, as a printing method capable of forming a sufficiently fine pattern having a good shape, a relief printing method (also referred to as a relief printing offset printing method) has attracted attention (see Patent Document 1).
The letterpress reversal printing method is a method of applying an ink composed of a polymer resin or the like on a blanket surface such as a silicone blanket so that the film thickness is uniform, and then a blanket having an ink layer formed on the surface and the letterpress. This is a printing method in which an unnecessary ink layer is transferred to and removed from a convex portion of a relief printing plate, and the ink layer remaining on the surface of the blanket is transferred to a printing material. For example, in Patent Document 1, by using the above-described relief printing method capable of continuous lamination (wet-on-wet), a significant cost reduction can be achieved while achieving the same accuracy as a color filter manufactured by a photoresist method. A method for producing a color filter having the same is described.

  As an example of an ink composition suitable for this relief printing method, for example, a printing ink composition characterized by having a colorant, a resin and a hydrocarbon solvent as essential components and having a viscosity of 50 mPa · s or less is used. It has been proposed (see Patent Document 2). The resin in this printing ink composition helps to reduce the colorant by adsorbing to the colorant, and also forms the desired pattern with the ability to prevent re-aggregation of the colorant after the reduction (dispersibility). It is essential to have the ability (printability) that can be performed and the ability to form a strong coating film after printing and maintain the shape (coating resistance). In addition, a printing ink composition containing a pigment, a resin, a surface energy adjusting agent, a fast-drying organic solvent, and a slow-drying organic solvent has been proposed (see Patent Document 3).

However, for example, a field requiring finer patterning as compared with the patterning of a color filter (line width 50 microns) as required in the above-mentioned document 2 or document 3, for example, a black matrix for various display elements, and a thin film transistor In such applications, it is difficult to form a desired pattern with the printing ink composition.
In recent years, from the viewpoint of high image quality design of various display elements, etc., an ink composition for letterpress reversal printing that can reproduce a finer pattern (with a line width of 40 microns or less) at a high optical density and has excellent durability. It was anxious.

JP 2001-56405 A JP 2005-54104 A JP 2005-128346 A

An object of the present invention is to provide an ink composition for letterpress reverse printing which can form a fine pattern with high optical density and has excellent durability when producing a black matrix for a color filter by the letterpress reverse printing method. It is to provide. Another object of the present invention is to provide an ink composition for letterpress reversal printing which can form a high precision pattern having a line width of 25 microns or less.

That is, the present invention is a printing ink composition containing a colorant, a dispersant, a binder resin, and a solvent, and used in a relief printing method,
The binder resin is a (meth) acrylic resin having a weight average molecular weight of 1000 to 5000 having a glass transition temperature of 25 ° C. or less, and an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and alkoxysilyl in one molecule. There is provided an ink composition for letterpress reversal printing, which has an average of at least two functional groups selected from the group consisting of groups in one molecule of a binder resin .

  In addition, the present invention provides an ink composition for letterpress reverse printing having desired film properties by thermally curing a functional group of a colorant, a functional group of a dispersant, and a functional group contained in a binder resin. Offer things.

  Moreover, this invention provides the printed matter obtained by the letterpress reverse printing method using the ink composition for letterpress reverse printing of the said description.

The present invention also provides a color filter produced by a letterpress reverse printing method using the above-described ink composition for letterpress reverse printing.
The present invention also provides a relief printing method using the above-described ink composition for relief printing.

By using the relief printing ink composition of the present invention, a printed matter having a high-definition pattern dimension and a good shape can be obtained.
The printed matter obtained by the relief printing method using the relief printing ink composition of the present invention can be effectively used as an insulating layer, a light shielding layer, a black matrix for a color filter, a shielding layer of a thin film transistor, and the like. .

(Ink composition for letterpress reverse printing)
The present invention will be described in detail below.
The ink composition for letterpress reversal printing of the present invention contains a colorant, a dispersant, a binder resin, and a solvent, and the binder resin has a weight average molecular weight of 1000 to 6000, an epoxy group, a hydroxyl group, An average of two or more functional groups selected from the group consisting of an acid group, an acid anhydride group, and an alkoxysilyl group are contained in one molecule of the binder resin.

(Coloring agent)
The colorant used in the present invention is not particularly limited as long as it is used as a colorant, and organic pigments, inorganic pigments and the like can be used. In particular, when the printing ink composition of the present application is used for forming a color filter, those commonly used as color filter pigments can be used, and among them, those having high color purity and color density and high transparency are preferred.
Examples of the organic pigment include azo, phthalocyanine, indigo, anthraquinone, perylene, quinacridone, methine / azomethine, and isoindolinone. Since the higher the dispersibility of the pigment, the more easily these characteristics are exhibited, so that an auxiliary agent such as a surface treatment or a surfactant can be added to the pigment as necessary. For these pigments, for example, pigment systems suitable for colored images such as red, green, blue and black are used. The type of pigment is a color index (CI) No. It shows with.

As the red colorant, a single red pigment system may be used, or a yellow pigment system may be mixed with a red pigment system to perform toning. Examples of the red pigment system include 9, 97, 122, 123, 149, 155, 168, 177, 180, 192, 208, 209, 215, 217, 220, 224, 254, and the like. Examples of the yellow pigment system include 7, 17, 20, 24, 36, 83, 93, 109, 110, 117, 125, 128, 129, 138, 139, 147, 150, 154, 180, 185, and the like. Is mentioned.
Two or more of these red pigment systems and yellow pigment systems can be used in combination.

  As the green colorant, a single green pigment system may be used, or the above yellow pigment system may be mixed with a green pigment system to perform toning. Examples of the green pigment system include 7, 36, 37, 58, and the like. Two or more of these green pigment systems and yellow pigment systems can be used in combination.

  As the colorant for the blue pigment, a single blue pigment system may be used, or the color may be adjusted by mixing a violet pigment system with a blue pigment system. Examples of the blue pigment system include 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64, and the like. Moreover, as a purple pigment type | system | group, 19, 23, 29, 37, 50, 122 etc. are mentioned, for example. Two or more of these blue pigment systems and purple pigment systems can be used in combination.

  Further, in order to improve the color adjustment of the red, green and blue pigments and the fluidity of the ink, the following pigments can be added in the required amounts. For example, white pigments include 18, 21, 27, 28, and orange pigments include 38, 43, and the like.

  In particular, when the ink composition for letterpress reversal printing of the present invention is used for forming a black matrix, carbon black, graphite, titanium black, black iron, manganese dioxide or the like is used as a black colorant. Normally, in the photoresist method, if an attempt is made to achieve the light shielding degree required for the black matrix (substitute with the optical density of black ink: hereinafter referred to as OD value) at a higher level, the light penetrates sufficiently in the exposure process. Insufficient exposure and poor development are likely to occur. On the other hand, the relief printing method according to the present invention does not go through an exposure step or the like, and thus does not cause the above-described problems as in the photoresist method. Therefore, a black matrix having a high OD value can be obtained. Specifically, when a black matrix is produced by a letterpress reverse printing method using the ink composition for letterpress reverse printing of the present invention, a black matrix having a transmission OD value of 3.5 or more per 1 micron film thickness is obtained. I can do it.

  These colorants can also be used in combination with inorganic transparent particles. Examples of the inorganic transparent particles include silica, magnesium fluoride, alumina, titanium oxide, barium titanate, and the like.

  Further, in order to impart conductivity to the coating film produced using the ink composition for letterpress reversal printing of the present invention, nickel, copper, gold, silver, aluminum, chromium, platinum (platinum), palladium, tungsten, molybdenum Etc., an alloy composed of two or more metals among these, or a compound of these metals having good conductivity can be used in combination.

Since the colorant is heat-cured at the time of pattern formation, it preferably has a functional group that can be thermally cured and a functional group that a binder resin described later has. For example, when the colorant has an acidic functional group such as a carboxyl group, a phosphoric acid group, a sulfonic acid group, or a neutralized product thereof (organic salt, inorganic salt, metal salt), the binder resin is an epoxy group, a hydroxyl group, It preferably has at least one functional group selected from the group consisting of alkoxyl groups, and the colorant is a basic functional group such as a primary, secondary, tertiary, quaternary amino group, or the like. When having a neutralized product (organic salt, inorganic salt, metal salt), the binder resin may have at least one functional group selected from the group consisting of an epoxy group, an acid group, an acid anhydride group, and an alkoxyl group. Preferably, when the colorant has a neutral functional group such as a hydroxyl group, an acid anhydride group, or a carbonyl group, the binder resin is selected from the group consisting of an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and an alkoxyl group. It is preferred to have the Kutomo one functional group.
Examples of such a colorant include a pigment having a functional group such as a carboxyl group, a carbonyl group, and a hydroxyl group in advance such as carbon black, and a functional pigment having a functional group introduced by various pigment surface treatments. There is no restriction | limiting in particular about the method of introduce | transducing a functional group on the pigment surface, For example, a plasma processing, a synergist processing, surfactant processing, a polymer processing etc. are mentioned.

(Dispersant)
The colorant can of course be used alone, but may be a dispersion in which the colorant is previously dispersed in an organic solvent. Especially, it is preferable that it is the dispersion liquid which disperse | distributed (miniaturized) the coloring agent using the dispersing agent.
The dispersant preferably has a functional group that can be thermally cured with a functional group that the binder resin described later has because it is heat-cured during pattern formation. For example, when the dispersant has an acidic functional group such as carboxyl group, phosphoric acid group, sulfonic acid group, or a neutralized product thereof (organic salt, inorganic salt, metal salt), the binder resin is an epoxy group, a hydroxyl group, It is preferable to have at least one functional group selected from the group consisting of alkoxyl groups, and the dispersant is a basic functional group such as a primary, secondary, tertiary, quaternary amino group, or the like. When having a neutralized product (organic salt, inorganic salt, metal salt), the binder resin may have at least one functional group selected from the group consisting of an epoxy group, an acid group, an acid anhydride group, and an alkoxyl group. Preferably, when the dispersant has a neutral functional group such as a hydroxyl group, an acid anhydride group, or a carbonyl group, the binder resin is selected from the group consisting of an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and an alkoxyl group. It is preferred to have the Kutomo one functional group.

Further, it is essential for the dispersant to have an ability (dispersibility) to help refining the colorant by adsorbing to the colorant and to prevent re-aggregation of the colorant after refining. Specifically, acidic functional groups such as carboxyl groups, phosphoric acid groups, and sulfonic acid groups having high affinity with colorants and neutralized salts thereof, or primary, secondary, tertiary, and quaternary What has in a molecule | numerator the at least 1 sort (s) of functional group chosen from the group which consists of basic functional groups, such as an amino group, and its neutralization salt is preferable.
Among such dispersants, an example is listed: Azisper PB-814, PB-821, PB-822, PB-824, PA-111 (Ajinomoto Fine Techno Co., Ltd.), Disperbyk-101, 102, 106 , 108, 109, 110, 111, 112, 116, 130, 140, 142, 145, 161, 162, 163, 164, 166, 167, 168, 170, 171, 174, 180, 181, 182, 183, 184 , 185, 187, 2000, 2001, 2008, 2009, 2010, 2015, 2020, 2025, 2050, 2070, 2090, 2091, 2095, 2096, 2150, 2153, 2155, 2163, 2164, BYK-LPN 21116, 6919 ·Japan( ) Product), EFKA-4010, 4020, 4320, 4330, 4401, 4570, 5054, 7461, 7462, 7476, 7477 (Ciba Specialty Chemicals), Solsperse 24000GR, 26000, 28000, 76500 (Lubrisol Corporation products) ) And the like.

(Binder resin)
The binder resin used in the present invention has a weight average molecular weight of 1000 to 6000, and at least one functional group selected from the group consisting of an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and an alkoxysilyl group, It is characterized by having an average of 2 or more in one molecule of the binder resin. By having the functional group, the binder resin reacts with the functional group of the binder resin and the pigment dispersant having a thermosetting functional group, or with the functional group of the binder resin and the thermosetting colorant, so that a strong coating is obtained. Since a film can be formed, the obtained pattern can maintain a good shape. In order to obtain a desired coating strength, the binder resin is an acrylic resin, and at least one functional group selected from the group consisting of an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and an alkoxysilyl group. It is desirable to have a structure in which two or more groups, preferably five or more groups are introduced into one molecule on average. When the average number of functional groups is less than 2 in one molecule, the desired coating film hardness may not be obtained.
The number of functional groups contained in the binder resin may be directly measured by sampling the obtained binder resin, but in the present invention, “the number of functional groups contained in one molecule of the binder resin = N” It calculated from the following formula.

  However, N represents the number of functional groups contained in one molecule of the binder resin, Mw represents the weight average molecular weight of the obtained binder resin, and W1, W2, W3. The weight fraction (%) of each monomer having a functional group with respect to the monomer charge amount is represented, and M1, M2, M3... Each represents the molecular weight of each monomer having a functional group.

The weight average molecular weight of the binder resin is determined by filtering a diluted solution obtained by diluting the resin 50 times with tetrahydrofuran (THF) with a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). Then, a measurement sample is prepared, and then this measurement sample is supplied to a gel permeation chromatograph (trade name “HLC-8220GPC” manufactured by GPC Tosoh Corporation), under conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C. The value obtained by measuring the polystyrene equivalent molecular weight of the resin was taken as the weight average molecular weight. In the GPC measurement, a column commercially available from Tosoh Corporation under the trade name “TSK-GEL HXL series” was used as a column, and a differential refractometer was used as a detector.

The binder resin is preferably a radical copolymer using a vinyl monomer as a raw material, and among them, an acrylic resin using a (meth) acryl monomer as a main raw material is preferable.
For example, a monomer having at least one functional group selected from the group consisting of an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and an alkoxysilyl group, methyl (meth) acrylate, ethyl (meth) acrylate, n- Propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) Various (meth) acrylates such as acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, dibromopropyl (meth) acrylate, tribromophenyl (meth) acrylate or alkoxyalkyl (meth) acrylate General purpose (meth) acrylate monomers such as styrene, α-methylstyrene, pt-butylstyrene or vinyltoluene, (meth) acrylonitrile, vinyl chloride, vinylidene chloride, vinyl fluoride or fluoride Vinylidene, (meth) acrylamide, dimethyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N-octyl (meth) acrylamide, N-butoxymethylacrylamide, diacetone acrylamide, dimethylaminopropyl (meth) acrylamide or alkoxyl It is prepared by copolymerization with vinyl monomers such as modified N-methylolated (meth) acrylamide.

  Examples of the monomer having an epoxy group include glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 4- (2,3-epoxypropoxy) butyl acrylate, and the like.

  Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl ( (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate, polyethylene glycol mono Various α, β-ethylenically unsaturated carboxylic acids such as (meth) acrylate, polypropylene glycol mono (meth) acrylate, “Placcel FM or Plaxel FA” (a caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.) And hydroxyalkyl esters.

  Examples of the monomer having an acid group include carboxyl group-containing monomers such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, or salts thereof, and 2-methacryloyloxyethyl acid phosphate. Examples thereof include phosphate ester group-containing monomers or salts thereof, sulfonic acid group-containing monomers such as t-butylacrylamide sulfonic acid, or salts thereof.

  Examples of the monomer having an acid anhydride group include (meth) acrylic anhydride, maleic anhydride, citraconic anhydride, and the like.

  Examples of the (meth) acrylic monomer having an alkoxysilyl group include α- (meth) acryloxypropyltrimethoxysilane, α- (meth) acryloxypropyltriethoxysilane, α- (meth) acryloxypropylmethyldiethoxy. Silane etc. are mentioned.

One kind or several kinds of monomers having these functional groups may be used, but combinations of functional groups capable of reacting with each other (for example, combinations of acid anhydride groups and hydroxyl groups, etc.) A combination of functional groups that do not react with each other is preferred because it may cause gelation during polymerization.
Examples of a preferable combination of monomers include an epoxy group-containing monomer such as glycidyl (meth) acrylate and a (meth) acrylate having an alkoxysilyl group such as α-methacryloxypropyltrimethoxysilane.

  In addition to the above method, the binder resin is a previously prepared (meth) acrylic resin and at least one functional group selected from the group consisting of an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and an alkoxysilyl group. It may be produced by introducing.

For example, in order to form a high-definition pattern having a line width of 25 microns or the like, even if the non-volatile content of the printing ink composition is increased, that is, the printing ink composition is reduced even if the solvent concentration in the printing ink composition is decreased. It is desirable to use a binder resin that does not excessively thicken, specifically, a (meth) acrylic resin that does not exhibit elastic behavior even under high non-volatile conditions.
The binder resin used in the present invention has a weight average molecular weight of 1000 to 6000. In order to reduce the influence of the elasticity of the resin, the molecular weight of the resin should be made smaller. Specifically, the molecular weight of the binder resin capable of forming high-definition patterning with a line width of 25 microns is preferably 1000 to 5000, more preferably 1500 to 3500 in terms of the weight average molecular weight. . When the weight average molecular weight is less than 1000, the hardness of the coating film may be insufficient and a high-definition pattern may not be maintained. When the molecular weight exceeds 6000, the (meth) acrylic resin has viscoelasticity. As a result, the desired high-definition patterning may not be formed.

  Further, the glass transition temperature (Tg) of the binder resin has a great influence on the formation of high-definition patterning. Therefore, the Tg of the binder resin is 25 ° C. or less, preferably 0 ° C. or less. When the Tg of the binder resin exceeds 25 ° C., the viscoelasticity of the (meth) acrylic resin may not be negligible, and as a result, the desired high-definition patterning may not be formed.

  The Tg of the binder resin may be measured directly by sampling the obtained binder resin. However, since it is complicated, in the present invention, the Tg calculated and calculated from the Tg of the homopolymer of the charged monomer is used. Specifically, Tg calculated by the following Fox equation is defined as “binder resin Tg” in the present invention.

なお上記式において、成分とは、バインダ樹脂を構成するモノマーを指す。

In the above formula, the component refers to a monomer constituting the binder resin.

  There is no limitation in particular as a manufacturing method of the said binder resin, It can superpose | polymerize by well-known methods, such as a block polymerization method and a solution polymerization method. The polymerization temperature is 40 to 140 ° C., and the polymerization time is about 5 to 24 hours.

The solvent used in the polymerization is not particularly limited. For example, toluene, xylene, cyclohexane, n-hexane or mineral spirit hydrocarbon, ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol Esters such as monomethyl ether acetate, butyl carbitol acetate or amyl acetate, ethers such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether or diethylene glycol, methyl ethyl ketone, methyl isobutyl ketone, methyl amino ketone, diisobutyl ketone Alternatively, ketones such as cyclohexanone, nitrogen-containing compounds such as N-methylpyrrolidone, isopropyl alcohol Is properly alcohol such as n- butanol, it is possible to use the "Swasol 310, Swasol 1000, SWASOL 1500" organic solvent aromatic petroleum solvent system such as [Cosmo Oil Co., Ltd.].
Further, the solvent used in the polymerization can be used as it is as a dilution solvent when preparing the pigment dispersion.

  Also, the polymerization initiator is not particularly limited. For example, a known azo radical polymerization initiator such as azobisisobutyronitrile, a known peroxide radical polymerization initiator such as benzoyl peroxide, Alternatively, two or more types can be used in combination. Moreover, it is also possible to use well-known chain transfer agents, such as a lauryl mercaptan, an octyl mercaptan, 2-mercaptoethanol, or thioglycolic acid, as a molecular weight regulator.

(Mixing ratio)
The solid content ratio of the colorant and the resin component (the sum of the dispersant and the binder resin) is preferably 1: 5 to 2: 1 by volume ratio, more preferably 1: 3 to 3: 2. is there. This ratio is the same even when the image is formed on the ink coating on the blanket surface by letterpress. If the solid content ratio between the colorant and the resin component is more than 2: 1 by volume, the colorant of the coating film is deteriorated because the colorant cannot be made fine due to insufficient dispersant, and the binder resin is insufficient. This is not preferable because the desired coating film hardness cannot be maintained, and when the volume ratio is less than 1: 5, the amount of the coloring agent in the coating film is too small to produce the desired color. It is not preferable.
When the relief printing ink composition blended at the above mass ratio is used for black matrix applications, a black matrix having a transmission OD value of 3.5 or more per 1 micron film thickness can be obtained.

(solvent)
As the solvent used in the present invention, a solvent that does not impair the dispersibility of the colorant is selected. Moreover, when coating using a slit coater, it is preferable to use it, combining a quick-drying organic solvent and a slow-drying organic solvent.
In the present invention, the quick-drying organic solvent is selected from the group consisting of an ester solvent, an alcohol solvent, an ether solvent, a ketone solvent, and a carbonate solvent having a vapor pressure at 25 ° C. of 20 × 10 ² Pa (15 mmHg) or more. And at least one organic solvent. The quick-drying organic solvent is preferably contained in the total ink composition in an amount of 5 to 90% by mass, more preferably 20 to 80% by mass, and further preferably 30 to 70% by mass. When the quick-drying organic solvent is less than 5% by mass, drying of the ink coating on the blanket is insufficient, resulting in poor reproducibility of the high-definition pattern, and when it exceeds 90% by mass, The ink coating becomes too dry and difficult to transfer to the relief plate or the substrate to be printed.

In addition, when the vapor pressure of the quick-drying organic solvent is less than 20 × 10 ² Pa (15 mmHg), the ink coating on the blanket is not sufficiently dried, and the ink coating is transferred to portions other than the relief printing plate. This is not preferable because a problem such as a good fine pattern not being formed on the top occurs.

The quick-drying organic solvent is selected in consideration of the solubility of the binder resin and the affinity for the colorant dispersion, and the following solvents are used as examples.
As ester solvents, for example, ethyl acetate, normal propyl acetate, isopropyl acetate, alcohol solvents, for example, methanol, ethanol, 1-propanol, 2-propanol, ketone solvents, for example, methyl ethyl ketone, methyl isobutyl ketone, carbonate Examples of the system solvent include dimethyl carbonate. These may be a single system or a mixture of a plurality of systems. Of these, isopropyl acetate, 2-propanol, and dimethyl carbonate are preferable in view of their evaporation rate and surface tension.

In the present invention, the slow-drying organic solvent is an ester solvent or an alcohol solvent of an organic solvent having a vapor pressure at 20 ° C. of 0.4 × 10 ² Pa (0.03 mmHg) or more and less than 20 × 10 ² Pa (15 mmHg). And at least one organic solvent selected from the group consisting of ether solvents, ketone solvents and carbonate solvents. The slow-drying organic solvent is preferably contained in the total ink composition in an amount of 5 to 90% by mass, more preferably 5 to 70% by mass, and still more preferably 10 to 30% by mass. When the slow-drying organic solvent is less than 5% by mass, the ink coating on the blanket becomes too dry to transfer onto the relief plate, and when it exceeds 90% by mass, the ink coating on the blanket is insufficiently dried. Therefore, such a problem that a good fine pattern cannot be formed is not preferable.
Further, when the vapor pressure of the slow-drying organic solvent is less than 0.4 × 10 ² Pa, the ink coating on the blanket is not sufficiently dried, or it takes a long time to dry, which is not preferable. In the case where the vapor pressure of the slow-drying organic solvent is 20 × 10 ² Pa or more, the ink coating on the blanket is excessively dried and is difficult to transfer to the relief plate or the substrate to be printed.

The slow-drying organic solvent is selected in consideration of the solubility of the binder resin and the affinity for the colorant dispersion, and the following solvents are used as examples.
As ester solvents, for example, propylene glycol monomethyl ether acetate, 3-methoxy-3-methyl-butyl acetate ("Solfit AC" trade name, manufactured by Kuraray Co., Ltd.), ethoxyethyl propionate, alcohol solvents, for example 1-butanol, 3-methoxy-3-methyl-1-butanol, 1-hexanol, 1-pentanol, 2-methyl 1-butanol, 4-methyl-2-pentanol, ether solvents such as propylene glycol monomethyl Ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol tertiary butyl ether, dipropylene glycol monomethyl ether, ethylene glycol butyl ether, ethylene glycol Examples of coal ethyl ether, ethylene glycol methyl ether, diethylene glycol butyl ether, diethylene glycol ethyl ether, and carbonate solvents include diethyl carbonate. In addition, these may be a single system or a mixture of a plurality of systems. Among these, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and diethyl carbonate are preferable in view of their evaporation rate and surface tension.

(Other ingredients)
The ink composition for letterpress reversal printing of the present invention may appropriately contain various additives such as a surface energy adjusting agent, an antifoaming agent, and an adhesion-imparting agent for a substrate to be printed, in addition to the components described above.

  The surface energy adjusting agent is added to make the surface energy of the ink composition smaller than the surface energy of the blanket surface so that the ink composition can be uniformly and satisfactorily applied to the blanket surface. As the surface energy adjusting agent, one or more of fluorine-based surfactants are used, and 0.05 to 5.0% by mass, preferably 0.1 to 1.0% by mass in the total ink composition. It is desirable to contain. Thereby, the smoothness of the coated film improves at the time of ink coating to a blanket, and a more uniform coating film is obtained. If the content of the surface energy adjusting agent is too small outside this range, the ink repelling on the blanket will occur or the ink coating will not be uniform and uneven, which is undesirable. After the transfer onto the base material, the surface energy adjusting agent in the ink coating film has a problem of inhibiting the adhesion between the substrate to be printed and the ink coating film, which is also not preferable.

  Specific examples of the surface energy adjusting agent include one or two types such as Megafuck F-470, Megafuck F-472, Megafuck F-482, and Megafuck F-484 (product of DIC Corporation). The above is used.

(Preparation method)
The ink composition for letterpress reversal printing of the present invention is prepared by first preparing a dispersion in which a colorant, a dispersant, and a solvent are dispersed to a desired dispersion state, and then adding a binder resin and an organic solvent to the prepared dispersion. And after mixing various additives, it is prepared by filtering coarse particles.
Specifically, a colorant, a dispersant, and a solvent are dispersed in advance to obtain a dispersion, and then the dispersion, the binder resin, and a surface energy adjusting agent as necessary are blended. Can be obtained by stirring.
Dispersion means used for dispersion is not particularly limited and known ones can be used. Examples thereof include a three roll mill, a two roll mill, a sand mill, an atrider, a bead mill, a ball mill, a kneader, and a paint shaker. It is done.

(viscosity)
When the ink composition for letterpress reversal printing of the present invention is applied using a slit coater, the viscosity is preferably in the range of 0.5 mPa · s to 10 mPa · s, more preferably 0.5 mPa · s to 5 mPa. -The range of s. This numerical value is determined in view of the ink dischargeability from the coating apparatus in order to uniformly apply the printing ink composition to the blanket. If the viscosity is higher than this range, the ink discharge from the coating device will be uneven, the printing ink composition will be divided on the blanket and applied, and the applied ink coating will be uneven This is not preferable.

(Printing method of ink composition for letterpress reverse printing)
The ink composition for letterpress reversal printing of the present invention is a printing ink composition suitable for forming a high-definition pattern used for a color filter such as a black matrix by the letterpress reversal printing method.
The printing method of the ink composition for letterpress reverse printing will be described. First, as shown in FIG. 1, the printing ink composition is applied to a roll-shaped blanket using a cap coater or the like. The cap coater supplies a printing ink composition by utilizing capillary action. After drying for several minutes, an unnecessary ink coating film is removed by pressing the letterpress on the ink coating film applied on the blanket. Thereafter, a desired pattern can be obtained by transferring the remaining ink coating film from the blanket surface to the substrate surface.

As a blanket, it is a roller-shaped member having releasability on the surface, for example, a sheet having releasability wound around the surface of a body that is a roll-shaped member composed of metal, resin, or the like, Examples include those obtained by treating the surface of the body with a release agent.
Examples of the sheet having releasability include a sheet made of a silicone resin or a fluororesin.
Examples of the release agent include silicone release agents such as dimethyl silicone oil, dimethyl silicone rubber, silicone resin, and organically modified silicone, and fluorine release agents such as polytetrafluoroethylene.

  The relief printing plate is not particularly limited, and examples thereof include a photosensitive resin, glass, and metal. Each member is etched to form a reverse pattern of the target shape.

  The substrate is selected depending on the application, for example, a transparent glass plate such as white plate glass, blue plate glass, and silica-coated blue plate glass, and a synthetic resin such as polyester resin, polycarbonate resin, (meth) acrylic resin, and vinyl chloride resin. Examples thereof include a sheet, a film or plate, a metal plate such as an aluminum plate, a copper plate, a nickel plate, and a stainless plate, other ceramic plates, and a semiconductor substrate having a photoelectric conversion element.

  Hereinafter, the present invention will be described with reference to examples. Unless otherwise specified, “part” and “%” are based on mass.

<Reference Example 1 Synthesis of Binder Resin (a) Having Thermosetting Functional Group>
Into a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 850 parts of propylene glycol monomethyl ether acetate was charged and heated to 100 ° C. while stirring. Next, a mixed solution consisting of 350 parts of 2-ethylhexyl acrylate, 400 parts of glycidyl methacrylate, “TSL-8370” (γ-methacryloxypropyltrimethoxysilane, product of Momentive Performance Materials LLC), A mixed solution consisting of 150 parts of “Perbutyl O” [Nippon Oil Co., Ltd.] and 150 parts of propylene glycol monomethyl ether acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 100 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid content solution of binder resin (a) which has a thermosetting functional group was obtained by depressurizingly removing at 70 degreeC.
The weight average molecular weight (hereinafter abbreviated as Mw) of the binder resin (a) having a thermosetting functional group measured by (Measurement 1: GPC measurement method) was 5,930 in terms of polystyrene. As a result, the binder resin (a) was found to have an average of 22.7 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (a) having a thermosetting functional group was −20 ° C.
Details of various property values of the binder resin (a) are shown in Table 1.

(Measurement 1: GPC measurement method)
A measurement sample was prepared by filtering the diluted solution obtained by diluting the resin 50 times with tetrahydrofuran (THF) through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The measurement sample is supplied to a gel permeation chromatograph (trade name “HLC-8220GPC” manufactured by GPC Tosoh Corp.) and measured under the conditions of a sample flow rate of 1 ml / min and a column temperature of 40 ° C. The measured value was defined as the weight average molecular weight. In the GPC measurement, a column commercially available from Tosoh Corporation under the trade name “TSK-GEL HXL series” was used as a column, and a differential refractometer was used as a detector.

<Reference Example 2 Synthesis of Binder Resin (b) Having Thermosetting Functional Group>
In a four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, 8000 parts of propylene glycol monomethyl ether acetate was charged and heated to 135 ° C. while stirring. Next, a mixed solution composed of 200 parts of styrene, 300 parts of 2-ethylhexyl acrylate, 100 parts of glycidyl methacrylate, 200 parts of methacrylic acid, 200 parts of maleic anhydride, 850 parts of propylene glycol monomethyl ether acetate, and “Perbutyl O” 150 A mixed solution consisting of 10 parts of “Perbutyl D” (product of NOF Corporation) and 150 parts of propylene glycol monomethyl ether acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid content solution of binder resin (b) which has a thermosetting functional group was obtained by carrying out the solvent removal under reduced pressure at 70 degreeC.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (b) having a thermosetting functional group was 1,860 in terms of polystyrene. As a result, the binder resin (b) was found to have an average of 9.4 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (b) having a thermosetting functional group was 30 ° C.
Details of various property values of the binder resin (b) are shown in Table 1.

<Reference Example 3 Synthesis of Binder Resin (c) Having Thermosetting Functional Group>
Into a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 2850 parts of propylene glycol monomethyl ether acetate was charged and heated to 135 ° C. while stirring. Next, 450 parts of n-butyl acrylate, 50 parts of t-butyl acrylate, 400 parts of glycidyl methacrylate, “SILQUEST ^* Y-9936” [γ-methacryloxypropyltriethoxysilane, Momentive Performance Materials LLC. Product] A mixed solution consisting of 100 parts, a mixed solution consisting of 150 parts of "Perbutyl O", 10 parts of "Perbutyl D", and 150 parts of propylene glycol monomethyl ether acetate were added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid solution of binder resin (c) having a thermosetting functional group was obtained by removing the solvent under reduced pressure at 70 ° C.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (c) having a thermosetting functional group was 2,330 in terms of polystyrene. As a result, it was found that the binder resin (c) has an average of 7.4 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (c) having a thermosetting functional group was −12 ° C.
Details of various property values of the binder resin (c) are shown in Table 1.

<Reference Example 4 Synthesis of Binder Resin (d) Having Thermosetting Functional Group>
Into a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 3850 parts of propylene glycol monomethyl ether acetate was charged and heated to 135 ° C. while stirring. Next, 230 parts of styrene, 600 parts of n-butyl acrylate, 50 parts of 2-hydroxyethyl methacrylate, 120 parts of “SILQUEST ^* Y-9936”, 150 parts of “Perbutyl O”, “Perbutyl D” A mixed solution consisting of 10 parts and 150 parts of propylene glycol monomethyl ether acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid content solution of binder resin (d) which has a thermosetting functional group was obtained by carrying out solvent removal under reduced pressure at 70 degreeC.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (d) having a thermosetting functional group was 2,130 in terms of polystyrene. As a result, the binder resin (d) was found to have an average of 1.7 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (d) having a thermosetting functional group was −19 ° C.
Details of various property values of the binder resin (d) are shown in Table 1.

<Reference Example 5 Synthesis of Binder Resin (e) Having Thermosetting Functional Group>
In a four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, 8000 parts of propylene glycol monomethyl ether acetate was charged and heated to 135 ° C. while stirring. Next, a mixed solution consisting of 50 parts of styrene, 300 parts of n-butyl acrylate, 300 parts of glycidyl methacrylate, 50 parts of maleic anhydride, 300 parts of “TSL-8370”, 850 parts of propylene glycol monomethyl ether acetate, A mixed solution consisting of 150 parts of “O”, 10 parts of “perbutyl D” and 150 parts of propylene glycol monomethyl ether acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid content solution of binder resin (e) which has a thermosetting functional group was obtained by carrying out solvent removal under reduced pressure at 70 degreeC.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (e) having a thermosetting functional group was 1,740 in terms of polystyrene. As a result, the binder resin (e) was found to have an average of 6.7 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (e) having a thermosetting functional group was −6 ° C.
Details of various property values of the binder resin (e) are shown in Table 1.

<Reference Example 6 Synthesis of Binder Resin (f) Having Thermosetting Functional Group>
Into a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 19850 parts of propylene glycol monomethyl ether acetate was charged and heated to 135 ° C. while stirring. Next, a mixed solution consisting of 400 parts of n-butyl acrylate, 300 parts of glycidyl methacrylate, 300 parts of “SILQUEST ^* Y-9936”, 200 parts of “Perbutyl O”, 10 parts of “Perbutyl D”, propylene glycol monomethyl ether A mixed solution consisting of 150 parts of acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid content solution of binder resin (f) which has a thermosetting functional group was obtained by carrying out vacuum desolvation at 70 degreeC.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (f) having a thermosetting functional group was 870 in terms of polystyrene. As a result, it was found that the binder resin (f) has an average of 2.7 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (f) having a thermosetting functional group was −9 ° C.
Details of various property values of the binder resin (f) are shown in Table 2.

<Reference Example 7 Synthesis of binder resin (g) having thermosetting functional group>
Into a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 1850 parts of propylene glycol monomethyl ether acetate was charged and heated to 135 ° C. while stirring. Next, a mixed solution consisting of 450 parts of 2-ethylhexyl acrylate, 400 parts of glycidyl methacrylate, 150 parts of “SILQUEST ^* Y-9936”, 150 parts of “Perbutyl O”, 10 parts of “Perbutyl D”, propylene glycol monomethyl ether A mixed solution consisting of 150 parts of acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid solution of binder resin (g) having a thermosetting functional group was obtained by removing the solvent under reduced pressure at 70 ° C.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (g) having a thermosetting functional group was 3,430 in terms of polystyrene. As a result, it was found that the binder resin (g) had an average of 11.4 thermosetting functional groups in one molecule.
In addition, Tg by the formula of Fox of the radically polymerizable monomer mixture used for binder resin (g) which has a thermosetting functional group was -21 degreeC.
Details of various property values of the binder resin (g) are shown in Table 2.

<Reference Example 8 Synthesis of Binder Resin (h) Having Thermosetting Functional Group>
In a four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, 8000 parts of propylene glycol monomethyl ether acetate was charged and heated to 135 ° C. while stirring. Next, a mixed solution consisting of 150 parts of styrene, 300 parts of n-butyl acrylate, 200 parts of glycidyl methacrylate, 150 parts of maleic anhydride, 200 parts of “TSL-8370”, 850 parts of propylene glycol monomethyl ether acetate, and “perbutyl” A mixed solution consisting of 150 parts of “O”, 10 parts of “perbutyl D” and 150 parts of propylene glycol monomethyl ether acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, the 70% solid content solution of binder resin (h) which has a thermosetting functional group was obtained by carrying out the vacuum solvent removal at 70 degreeC.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (h) having a thermosetting functional group was 1,730 in terms of polystyrene. As a result, the binder resin (h) was found to have an average of 6.5 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (h) having a thermosetting functional group was 7.6 ° C.
Details of various property values of the binder resin (h) are shown in Table 2.

<Reference Example 9 Synthesis of Binder Resin (i) Having Thermosetting Functional Group>
A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was charged with 8850 parts of propylene glycol monomethyl ether acetate and heated to 135 ° C. while stirring. Next, 300 parts of n-butyl acrylate, 300 parts of 2-ethylhexyl acrylate, 100 parts of 2-hydroxyethyl methacrylate, 300 parts of “SILQUEST ^* Y-9936”, 150 parts of “Perbutyl O”, A mixed solution consisting of 10 parts of “Perbutyl D” and 150 parts of propylene glycol monomethyl ether acetate was added dropwise over 5 hours. After the completion of dropping, the reaction was carried out at 135 ° C. for 12 hours, and then sampling was performed to measure the nonvolatile content. Furthermore, 70% solid content solution of binder resin (i) which has a thermosetting functional group was obtained by carrying out solvent removal under reduced pressure at 70 degreeC.
Mw measured by (Measurement 1: GPC measurement method) of the binder resin (i) having a thermosetting functional group was 1,810 in terms of polystyrene. As a result, it was found that the binder resin (i) has an average of 3.3 thermosetting functional groups in one molecule.
In addition, Tg by the Fox formula of the radical polymerizable monomer mixture used for the binder resin (i) having a thermosetting functional group was −33 ° C.
Details of various property values of the binder resin (i) are shown in Table 2.

<Preparation of Reference Example 10 Dispersion (A)>
"DISPERBYK-164" which is a basic dispersant as a dispersant [BIC Chemie Japan Co., Ltd. product, solid content 60%] 8.3 parts, "carbon black (1)" as a colorant [primary particle size of pigment 30 nanometers, carboxyl group, sulfonic acid group, hydroxyl group, and carbonyl group are present on the pigment surface] 25 parts, 46.7 parts of isopropyl acetate and 20 parts of diethyl carbonate as a solvent are blended and dispersed using a bead mill. Thus, a dispersion (A) was obtained.
The viscosity of dispersion (A) at 25 ° C. was 2.1 mPa · s as measured with a cone-plate rotary viscometer [TV-20L, product of Toki Sangyo Co., Ltd.]. there were.
Various property values of the dispersion (A) are shown in Table 3.

<Preparation of Reference Example 11 Dispersion (B)>
Binder resin (c) (containing 70% solid content epoxy group and alkoxysilane group) 7.1 parts as dispersant, 25 parts “carbon black (1)” as colorant, 47.9 parts isopropyl acetate as solvent and diethyl Dispersion liquid (B) was obtained by mix | blending 20 parts of carbonate and performing a dispersion process using a bead mill.
The obtained dispersion (B) was subjected to a dispersion treatment using the binder resin (c) having poor dispersibility of the colorant, so that the viscosity at 25 ° C. greatly exceeded 10 mPa · s and the fluidity was very low. It became a paste-like dispersion.
Various property values of the dispersion (B) are shown in Table 3.

<Example 1 Preparation and Evaluation of Ink Composition for Reversal Printing (1)>
Dispersion (A) 43.3 parts as a dispersion, binder resin (c) (solid content 70%) 5.6 parts as a binder resin, isopropyl acetate 48.6 parts and diethyl carbonate 1.4 parts as a solvent, additive 0.3 parts of "MegaFuck F-482" [DIC Corporation product, solid content 30%] and 0.8 parts of "PTG-L1000" [Hodogaya Chemical Co., Ltd. product, solid content 100%] The mixture was mixed and stirred with a disper to obtain an ink composition for letterpress reversal printing (1).
The ink composition for letterpress reverse printing (1) had a viscosity at 25 ° C. of 1.5 mPa · s and was an ink composition for letterpress reverse printing with high fluidity.
Various property values of the ink composition for letterpress reverse printing (1) are shown in Table 4.

(Production of black matrix ink cured film A)
As shown in FIG. 1A, the ink composition for letterpress reverse printing (1) was applied to the surface of the silicone blanket 2 using a cap coater and then dried for several minutes to obtain a theoretical film thickness of 1.0 micron. A black matrix ink coating 1A was prepared.
Next, as shown in FIG. 1 (b), the blanket 2 having the ink coating layer 3 formed on the surface thereof is rolled while being brought into contact with a glass relief plate 4 having a reverse pattern with a line width of 25 microns. Then, the convex portion of the relief plate 4 was brought into contact with the ink coating layer 3, and an unnecessary portion (non-pixel portion) of the blanket surface 2 was transferred to the convex portion and removed.
Thereafter, as shown in FIG. 1 (c), the ink coating film 3 produced on the silicone blanket 2 was transferred to a glass substrate 5. The glass substrate having the transferred material was heated in a dryer at 230 ° C. for 30 minutes to obtain a black matrix ink cured coating film 1A having a high-definition patterning having a line width of 25 microns. Similarly, after being applied to a blanket, dried, transferred to a glass substrate without contact with the relief plate, and heated at 230 ° C. for 30 minutes, the transmission OD value of the black matrix ink-cured coating film 1A was determined as a black and white transmission densitometer [ X-Rite 361T, distributor: Japan Flat Plate Equipment Co., Ltd.].

(Image patterning evaluation)
The accuracy and shape of the line pattern of the obtained black matrix ink-cured coating film 1A were observed with a transmission microscope and determined as follows.
A: Patterning is completely reproduced, and the line width is about 25 microns (pass).
○: Patterning is completely reproduced and the line width is 28 microns or less (pass)
X: Patterning is unclear or incomplete, or the line width is larger than 28 microns (failed)

(Production of black matrix ink cured film B)
As shown in FIG. 1A, the ink composition for letterpress reverse printing (1) was applied to the surface of the silicone blanket 2 using a cap coater and then dried for several minutes to obtain a theoretical film thickness of 1.0 micron. A black matrix ink coating 1B was prepared.
Next, as shown in FIG. 1 (b), the blanket 2 having the ink coating layer 3 formed on the surface is rolled while being brought into contact with a glass relief plate 4 having a reverse pattern with a line width of 40 microns. Then, the convex portion of the relief plate 4 was brought into contact with the ink coating layer 3, and an unnecessary portion (non-pixel portion) of the blanket surface 2 was transferred to the convex portion and removed.
Thereafter, as shown in FIG. 1 (c), the ink coating film 3 produced on the silicone blanket 2 was transferred to a glass substrate 5. The glass substrate having the transferred material was heated in a dryer at 230 ° C. for 30 minutes to obtain a black matrix ink cured coating film 1B having fine patterning with a line width of 40 microns. Similarly, after being applied to a blanket, dried, transferred to a glass substrate without being contacted with a relief plate, and heated at 230 ° C. for 30 minutes, the transmission OD value of the ink cured coating film 1B for black matrix obtained was measured using a black and white transmission densitometer X-Rite 361T, distributor: Japan Flat Plate Equipment Co., Ltd.].

(Image patterning evaluation)
The accuracy and shape of the line pattern of the obtained black matrix ink cured coating film 1B were observed with a transmission microscope and determined as follows.
A: Patterning is completely reproduced, and the line width is approximately 40 microns (pass).
○: Patterning is completely reproduced and the line width is 43 microns or less (pass)
X: Patterning is unclear or incomplete, or the line width is larger than 43 microns (fail)

(Solvent rubbing resistance evaluation of black matrix ink cured coating)
The ink composition (1) for letterpress reversal printing was applied to a 5 × 5 cm glass plate using a spin coater, and then heated at 230 ° C. for 30 minutes to obtain a black matrix ink cured coating 1C.
The obtained black matrix ink cured coating 1C was rubbed with a cotton swab moistened with isopropyl alcohol or methyl ethyl ketone. By observing the ink-cured coating film and the cotton swab after rubbing, the solvent rubbing resistance of the ink-cured coating film was evaluated and judged as follows.
> 30: The ink cured coating did not peel off even after rubbing 30 times with a solvent, and the cotton swab was not colored (pass)
30: The ink-cured coating film did not peel off even after rubbing 30 times with a solvent. A small amount of black on a cotton swab (pass)
Less than 30: The ink-cured coating film has been peeled off (failed)
Table 4 shows the evaluation results of the ink composition for letterpress reverse printing (1).

<Example 2 Preparation and Evaluation of Ink Composition for Reversal Printing (2)>
An ink composition (2) for letterpress reverse printing was prepared in the same manner as in Example 1 except that the binder resin (e) was used as the binder resin when blending the ink composition for letterpress reverse printing.
The resulting relief printing ink composition (2) was evaluated in the same manner as in Example 1, and the results are shown in Table 4.

<Example 3 Preparation and evaluation of ink composition (3) for letterpress reversal printing>
An ink composition (3) for letterpress reverse printing was prepared in the same manner as in Example 1 except that the binder resin (g) was used as the binder resin when blending the ink composition for letterpress reverse printing.
The obtained ink composition for letterpress reverse printing (3) was evaluated in the same manner as in Example 1, and the results are shown in Table 4.

< Comparative Example 6 Preparation and Evaluation of Ink Composition for Reversal Printing (6)>
An ink composition for letterpress reverse printing (6) was prepared in the same manner as in Example 1 except that the binder resin (a) was used as the binder resin when blending the letterpress reverse printing ink composition.
The obtained ink composition for letterpress reverse printing (6) was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

< Comparative Example 7 Preparation and Evaluation of Ink Composition for Reversal Printing (7)>
An ink composition for letterpress reverse printing (7) was prepared in the same manner as in Example 1 except that the binder resin (b) was used as the binder resin when blending the letterpress reverse printing ink composition.
The obtained relief printing ink composition (7) was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

< Comparative Example 8 Preparation and Evaluation of Ink Composition for Reversal Printing (8)>
Ink composition for letterpress reversal printing in the same manner as in Example 1 except that binder resin (a) was used as the binder resin and 10 parts of isopropyl acetate was replaced with 10 parts of octane as the solvent at the time of blending the printing ink composition. 8) was produced.
The obtained relief printing ink composition (8) was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

<Example 7 Preparation and Evaluation of Ink Composition for Reversal Printing (7)>
An ink composition for letterpress reverse printing (7) was prepared in the same manner as in Example 1 except that the binder resin (b) was used as the binder resin when blending the letterpress reverse printing ink composition.
The obtained relief printing ink composition (7) was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

<Example 8 Preparation and Evaluation of Ink Composition for Reversal Printing (8)>
Ink composition for letterpress reversal printing in the same manner as in Example 1 except that binder resin (a) was used as the binder resin and 10 parts of isopropyl acetate was replaced with 10 parts of octane as the solvent at the time of blending the printing ink composition. 8) was produced.
The obtained relief printing ink composition (8) was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

<Comparative Example 1 Preparation and Evaluation of Ink Composition for Reversal Printing (11)>
An ink composition (11) for letterpress reverse printing was prepared in the same manner as in Example 1 except that the binder resin was not used when the ink composition for letterpress reverse printing was blended.
The obtained relief printing ink composition (11) was evaluated in the same manner as in Example 1, and the results are shown in Table 6.

<Comparative Example 2 Preparation and Evaluation of Ink Composition for Reversal Printing (12)>
Ink composition for letterpress reverse printing (12) in the same manner as in Example 1 except that the dispersion liquid (B) was used as the dispersion liquid and no binder resin was used when blending the ink composition for letterpress reverse printing. Was made.
The obtained relief printing ink composition (12) was evaluated in the same manner as in Example 1, and the results are shown in Table 6.

As is clear from the results of Tables 4 and 5, the black matrix produced from the printing ink compositions obtained in Examples 1 to 5 and Comparative Examples 6 to 8 has a film thickness of 1.0 microns and a unit OD value. The image line pattern having a high value of 4.0 and a line width of 50 microns was completely reproduced. Moreover, the hardness of the cured coating film was also at a desired level as seen in good solvent rubbing resistance.
Among them, the black matrix produced from the printing ink compositions obtained in Examples 1 to 5 has a weight average molecular weight of 5000 or less, a glass transition temperature of 25 ° C. or less, and a functional per molecule. Since a binder resin having an average of 2 or more radix was used, the unit OD value was as high as 4.0 with a film thickness of 1.0 micron, and not only a line width of 40 micron, but also a high line width of 25 microns. The fine line pattern was completely reproduced. In particular, the black matrix produced from the printing ink composition obtained in Examples 1 and 2 has a weight average molecular weight of 3000 or less, a glass transition temperature of 0 ° C. or less, and a functional per molecule. Since a binder resin having an average number of 5 or more was used, the reproduction of high-definition line patterning with a line width of 25 microns and the hardness of the cured coating film were particularly excellent.
On the other hand, as seen in Table 6, in Comparative Example 1, because no binder resin was used when the printing ink composition was prepared, an image line pattern having a line width of 25 microns and a line width of 40 microns could not be formed. Moreover, the rubbing resistance of the cured coating film was also poor. In Comparative Example 2, since the dispersion liquid (B) produced using the binder resin (c) having a poor ability to refine the colorant was used, and the binder resin was not added at the time of blending the ink composition for letterpress reversal printing, black The unit OD value of the matrix was very low, image line patterning with a line width of 25 microns and a line width of 40 microns could not be reproduced, and the solvent rubbing resistance was also poor. In Comparative Example 3, since the binder resin (d) having an average number of functional groups per molecule of less than 2 was used, the solvent rubbing resistance of the coating film was poor. In Comparative Example 4, since the binder resin (f) having a weight average molecular weight of less than 1000 was used, the solvent rubbing resistance of the coating film was poor.

<Comparative Example 4 Preparation and Evaluation of Ink Composition for Reversal Printing (14)>
An ink composition for letterpress reverse printing (14) was prepared in the same manner as in Example 1 except that the binder resin (f) was used as the binder resin when blending the letterpress reverse printing ink composition.
The obtained relief printing ink composition (14) was evaluated in the same manner as in Example 1, and the results are shown in Table 6.

As is clear from the results of Tables 4 and 5, the black matrix produced from the printing ink compositions obtained in Examples 1 to 8 had a film thickness of 1.0 microns and a high unit OD value of 4.0, and The line pattern with a line width of 40 microns was completely reproduced. Moreover, the hardness of the cured coating film was also at a desired level as seen in good solvent rubbing resistance.
Among them, the black matrix produced from the printing ink compositions obtained in Examples 1 to 5 has a weight average molecular weight of 5000 or less, a glass transition temperature of 25 ° C. or less, and a functional per molecule. Since a binder resin having an average of 2 or more radix was used, the unit OD value was as high as 4.0 with a film thickness of 1.0 micron, and not only a line width of 40 micron, but also a high line width of 25 microns. The fine line pattern was completely reproduced. In particular, the black matrix produced from the printing ink composition obtained in Examples 1 and 2 has a weight average molecular weight of 3000 or less, a glass transition temperature of 0 ° C. or less, and a functional per molecule. Since a binder resin having an average number of 5 or more was used, the reproduction of high-definition line patterning with a line width of 25 microns and the hardness of the cured coating film were particularly excellent.
On the other hand, as seen in Table 6, in Comparative Example 1, because no binder resin was used when the printing ink composition was prepared, an image line pattern having a line width of 25 microns and a line width of 40 microns could not be formed. Moreover, the rubbing resistance of the cured coating film was also poor. In Comparative Example 2, since the dispersion liquid (B) produced using the binder resin (c) having a poor ability to refine the colorant was used, and the binder resin was not added at the time of blending the ink composition for letterpress reversal printing, black The unit OD value of the matrix was very low, image line patterning with a line width of 25 microns and a line width of 40 microns could not be reproduced, and the solvent rubbing resistance was also poor. In Comparative Example 3, since the binder resin (d) having an average number of functional groups per molecule of less than 2 was used, the solvent rubbing resistance of the coating film was poor. In Comparative Example 4, since the binder resin (f) having a weight average molecular weight of less than 1000 was used, the solvent rubbing resistance of the coating film was poor.

Since the ink composition for letterpress reversal printing of the present invention obtains a printed matter having a high-definition pattern size and a good shape, insulation for electronic components such as various circuit boards, liquid crystal display elements, organic electroluminescence elements, and thin film transistors. It can be particularly effectively used for forming pattern shapes such as a layer, a light shielding layer, a black matrix of a color filter, and a light shielding design layer around the display.

The schematic block diagram which shows typically an example of the relief printing method in this invention.

1. 1. Ink application device Blanket3. 3. Ink coating film Letterpress 5. Printed substrate

Claims (10)

A printing ink composition containing a colorant, a dispersant, a binder resin, and a solvent, and used in a relief printing method,
The binder resin is a (meth) acrylic resin having a weight average molecular weight of 1000 to 5000 having a glass transition temperature of 25 ° C. or less , and an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and alkoxysilyl in one molecule. An ink composition for letterpress reversal printing, having an average of at least two functional groups selected from the group consisting of groups in one molecule of a binder resin. The ink composition for letterpress reverse printing according to claim 1, which is used in a letterpress printing method for forming a pattern having a line width of 25 microns or less. The ink composition for letterpress reverse printing according to claim 1 or 2, wherein the dispersant has a functional group capable of reacting with a functional group of the binder resin. The ink composition for letterpress reverse printing according to any one of claims 1 to 3, wherein the colorant has a functional group capable of reacting with a functional group of the binder resin. The ink composition for letterpress reverse printing according to any one of claims 1 to 4, wherein the printing ink composition is used for a black matrix for a color filter. The ink composition for letterpress reverse printing according to claim 5, comprising at least one selected from the group consisting of carbon black, graphite, titanium black, black iron, and manganese dioxide as a colorant. The printed matter obtained by the letterpress reverse printing method using the ink composition for letterpress reverse printing in any one of Claims 1-6. The color filter produced by the letterpress reverse printing method using the ink composition for letterpress reverse printing in any one of Claims 1-6. A printing ink composition containing a colorant, a dispersant, a binder resin, and a solvent, and used in a relief printing method,
The binder resin is a (meth) acrylic resin having a weight average molecular weight of 1000 to 5000 having a glass transition temperature of 25 ° C. or less, and an epoxy group, a hydroxyl group, an acid group, an acid anhydride group, and alkoxysilyl in one molecule. A letterpress reverse printing method comprising using an ink composition for letterpress reverse printing having an average of at least two functional groups selected from the group consisting of groups in one molecule of a binder resin. The relief printing method according to claim 9, wherein a pattern having a line width of 25 microns or less is formed.

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