KR20110071906A - Ink composition for color filter - Google Patents

Abstract

PURPOSE: An ink composition for a color filter is provided to prevent the degradation of contrast ratio after high temperature treatment by adding a melamine compound and to improve ink dispersibility. CONSTITUTION: An ink composition for a color filter comprises pigment, binder resin and polymerizable monomer, and further a melamine compound. The melamine compound has an average molecular weight of 126~5000 and includes compounds represented by chemical formula 1 and one or more polymers between the compounds. In chemical formula 1, R1, R2, R3, R4, R5 and R6 are respectively independent a compound including hydrogen, C1-6 alkyl group, C1-6 alkoxy group, carboxyl group, C1-6 ether group, C1-6 alcohol group, amino group, nitro group, hydroxyl group, phenyl group, or acryl group.

Description

Ink composition for color filters {INK COMPOSITION FOR COLOR FILTER}

The present invention relates to an ink composition for a color filter and a color filter made of the ink composition.

A typical liquid crystal display device includes a liquid crystal layer sandwiched between two polarizing plates, the first polarizing plate controls the degree of polarization of the light passing through, and the second polarizing plate is operated in a manner of adjusting the amount of light passing through. Such a liquid crystal display device is capable of color display by providing a color filter between two polarizing plates. Recently, liquid crystal display devices have been widely used in televisions and PC monitors, and high brightness and high contrast are required for color filters. It is rising.

A color filter is what arrange | positioned two or more types of fine strip | belt (stripe) shape filter segments of parallel or crossed on the surface of transparent substrates, such as glass, or arrange | positioned the fine filter segments in fixed arrangement. The filter segments are fine in the order of several micrometers to several 100 micrometers, and are arranged in a predetermined arrangement for each color.

In general, in a color liquid crystal display device, a transparent electrode for driving a liquid crystal on a color filter is formed by vapor deposition or sputtering, and an alignment film for aligning the liquid crystal in a predetermined direction is formed thereon. In order to fully acquire the performance of these transparent electrodes and an oriented film, the formation needs to be performed generally at 200 degreeC or more, Preferably it is 230 degreeC or more high temperature. For this reason, the pigment dispersion method is mainly used as a manufacturing method of a color filter at present. The said pigment dispersion method is a method of using the pigment excellent in light resistance and heat resistance as a coloring agent.

However, the color filter which disperse | distributed the pigment generally has a problem that the polarization degree controlled by the liquid crystal is disperse | distributed by scattering of the light by a pigment. That is, since the light leaks when it is necessary to block the light (OFF state) or the transmitted light is attenuated when it is required to transmit the light (ON state), the ratio of the luminance on the display device in the ON state and the OFF state ( There is a problem that the contrast ratio is low.

Although the filter segment is formed using the coating liquid of the color resist formed by mix | blending a photoinitiator and ethylenically unsaturated monomer with a pigment dispersion, in order to implement | achieve high brightness and high contrast of a color filter, it is contained in a filter segment first. It is necessary to prepare the pigment dispersion which carried out the pigment refinement | miniaturization and stably disperse | distributed this refinement pigment in the pigment carrier which consists of resin etc. (for example, refer Unexamined-Japanese-Patent No. 10-130547).

However, when the aggregation of the pigment is strong and it is not possible to disperse all of it, the pigment and the contrast ratio of the color filter are lowered by going through the pigment miniaturization step. Moreover, when the dispersion stability of a pigment dispersion is low, aggregation of a pigment particle advances with time, raises the viscosity of a coloring composition, and causes fluidity defect, and spin-coats a coating liquid on a glass substrate, when forming a filter segment. In some cases, such as poor coating performance, poor leveling, or the like, a coating film with a uniform film thickness cannot be obtained, which is not preferable.

In order to stabilize the pigment dispersion using such a micronized pigment, dispersion formulation optimization using a pigment derivative or a resinous dispersant has been performed, and improvement of the pigment derivative, the resinous dispersant or a binder resin has also been carried out (for example, Japanese Patent Laid-Open No. 2005). -181383). However, in these methods, there are cases where it is insufficient to fully exhibit the performance of high quality micronized pigments in recent years.

In addition, even when the dispersion of the micronized pigment can be prepared and a high contrast filter segment can be formed, the filter segment is formed in the same manner as described above for the formation of the color filter (transparent electrode and alignment film formation, post-baking step). Exposed to a high temperature of 230 ° C. or higher, the dispersion system of the pigment collapses and the contrast ratio may decrease.

Currently, the pigment dispersion method of heat resistance and light resistance is mainly used as a method of manufacturing a color filter. A color filter in which a pigment is dispersed causes a scattering of light passing between two polarizing plates, thereby lowering a contrast ratio. have. In particular, when the particle size of the pigment is large, the scattering of light is increased to reduce the contrast ratio.

Therefore, in order to realize a high contrast ratio, it is necessary to refine the particle size of the pigment, but when the particle size of the pigment is reduced, the surface energy of the pigment particles increases, and another problem of inferior dispersion stability occurs. If the dispersion stability of the pigment is poor, aggregation of the pigment particles may occur, and the contrast ratio may be lowered, and problems such as unstable jetting or clogging of the nozzle due to viscosity increase, gelation, etc. of the ink composition may occur. May occur.

Generally, in order to disperse the finely pigmented pigments, pigment derivatives, resinous dispersants (polymeric dispersants) and the like are used, and various kinds of patents have been applied for them. However, pigment derivatives or dispersants alone cannot prevent the aggregation of pigments or the deterioration of pigment dispersibility that occur during the high temperature treatment of the ink in which the micronized pigment is dispersed (heat treatment at 200 ° C. or higher, for example, post-baking process). . The decrease in pigment dispersibility occurring in the process after the high temperature treatment has a problem that leads to a decrease in the contrast ratio.

Accordingly, the present invention is to provide a color filter ink composition excellent in heat resistance, high contrast and excellent fluidity in order to solve the problems of the prior art described above.

The present invention has been made to solve the above problems of the prior art,

In the ink composition for color filters containing a pigment, binder resin, and a polymerizable monomer,

It further comprises a melamine compound,

The melamine compound has a weight average molecular weight in the range of 126 ~ 5000, and provides an ink composition for a color filter, characterized in that it comprises at least one of a compound, and a polymer therebetween.

[Formula 1]

(Wherein the _{R 1, R 2, R 3} , R 4, R 5 and R ₆ is an alkoxy group, a carboxyl group, a C _1-6 alkyl group, C _1-6 of hydrogen, C _1-6 each independently Compound containing an alcohol group, a C _1-6 alcohol group, an amino group, a nitro group, a hydroxyl group, a phenyl group or an acryl group)

In addition, in the present invention, the compound represented by the formula (1) provides a color filter ink composition, characterized in that the compound represented by the formula (2).

[Formula 2]

Where R _1a , R _2a and R _3a They are each independently of each other by means a hydrogen, an alkyl group or a (meth) acrylate of a C _{1 -6)}

In addition, in the present invention, the compound represented by Formula 1 provides a color filter ink composition, characterized in that the compound represented by the following formula (3).

(3)

Wherein R _1b , R _2b , R _3b , R _4b , R _5b and R _6b They are each independently of each other by means a hydrogen, an alkyl group or a (meth) acrylate of a C _{1 -6)}

In addition, in the present invention, the compound represented by the formula (1) provides a color filter ink composition, characterized in that one of the compounds represented by the following formula (4) to formula (7).

In addition, in the present invention, the melamine compound provides an ink composition for a color filter, characterized in that included in the range of 1 to 20 wt% based on the total composition.

In addition, in the present invention, further comprising a pigment dispersant, wherein the pigment is 5 to 20 wt% based on the total composition, the pigment dispersant is 1 to 10 wt%, the polymerizable monomer is contained within the range of 0.5 to 8 wt% It provides an ink composition for a color filter, characterized in that.

In addition, in the present invention, there is provided an ink composition for a color filter, further comprising an additive.

In addition, in the present invention, the viscosity of the ink composition provides a color filter ink composition, characterized in that within the range of 10 to 18 cP.

In addition, the present invention provides a color filter, which is prepared from the ink composition of the present invention.

By adding a melamine compound, the color filter ink composition of the present invention can prevent a phenomenon in which the contrast ratio after a high temperature treatment is lowered, and has an effect of further improving the dispersibility of the ink. In addition, there is an effect of lowering the viscosity of the ink, there is an effect that can increase the solids more than when not adding the melamine compound.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention,

In the ink composition for color filters containing a pigment, binder resin, and a polymerizable monomer,

It further comprises a melamine compound,

The melamine compound is characterized in that it comprises a weight average molecular weight in the range of 126 ~ 5000, at least one of a compound represented by the following formula (1), and a polymer therebetween.

[Formula 1]

(Wherein the _{R 1, R 2, R 3} , R 4, R 5 and R ₆ independently of one another are each hydrogen, C _{1 -6} alkyl, C _{1 -6} alkoxy group, a carboxyl group, C _{1 -6} of the refers to a compound containing an ether group, an alcohol group in the C _{1 -6,} an amino group, a nitro group, a hydroxyl group, a phenyl group or an acrylic group)

The melamine compound is represented by Chemical Formula 1, and the melamine compound serves to improve heat resistance of the ink. That is, the pigment dispersibility is broken during the high temperature treatment of the post-baking process or post-process (formation of alignment film, etc.) for forming the ink film, resulting in a phenomenon such as pigment aggregation, which serves to prevent the contrast of the color filter film from decreasing. In particular, it is preferable that at least two of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ of the compound of Formula 1 have a substituent other than hydrogen. This is because, when the melamine compound has a substituent other than hydrogen, crosslinking with other compounds is good, and thus the heat resistance and the dispersibility of the pigment can be improved. More preferably, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ of the compound of Formula 1 have a substituent other than at least 3 hydrogen.

In addition, since the viscosity of the melamine compound is lower than that of a binder or a commonly used crosslinking agent, the viscosity of the melamine compound is relatively low when added to the ink. Usually ink compositions for color filters for inkjet processes have a suitable viscosity for jetting in the range of 10-18 cP. When the melamine compound is added to the ink instead of the cross-linker of the binder resin, since the melamine compound plays a role of crosslinking between the binder resins, the content of the crosslinking agent usually included by adding the melamine compound can be reduced. Therefore, the viscosity of the ink is lowered, there is an advantage that can increase the relatively solid content. That is, when the melamine compound is not added, the solid content cannot be increased due to the constraint of viscosity, but since the melamine compound is added, the viscosity can be increased, thereby increasing the solid content by about 1 to 2%. In the inkjet process, the higher the solids content of the ink, the smaller the number of drops of ink filling the pixels, and thus, there are process advantages (reduced step height and reduced tack time in the pixel, etc.). .

In particular, the compound of Chemical Formula 1 is preferably a compound represented by the following Chemical Formula 2 or Chemical Formula 3.

[Formula 2]

Where R _1a , R _2a and R _3a They are each independently of each other by means a hydrogen, an alkyl group or a (meth) acrylate of a C _{1 -6)}

(3)

Wherein R _1b , R _2b , R _3b , R _4b , R _5b and R _6b They are each independently of each other by means a hydrogen, an alkyl group or a (meth) acrylate of a C _{1 -6)}

The melamine compound is in the range of the weight average molecular weight 126 ~ 5000. If it is within the above, the contrast ratio after high temperature treatment is effective in preventing a fall (refer the Example mentioned later). In particular, when the weight average molecular weight of the melamine compound exceeds 5000, since the viscosity tends to increase, there is a fear that jetting may not be performed well. Preferably the weight average molecular weight is 200 to 4000, more preferably the weight average molecular weight is within the range of 300 to 3000.

The melamine compound is preferably included 1 to 20 wt% based on the total composition. In the case where the melamine compound is included in less than 1 wt%, the effect of reducing the contrast ratio after the high temperature treatment and the effect of improving the dispersibility of the ink may be insignificant. You can't. In particular, when the content of the pigment is reduced too much, there is a fear that a desired color cannot be obtained at a desired thickness.

Although the said pigment can mix and use two or more types of organic or inorganic pigments, it is especially preferable to use the organic pigment with high coloring property and heat resistance.

Below, the specific example of the pigment which can be used for the coloring composition of this invention is shown by a color index number.

CI Pigment Red 7, 14, 41, 48: 1, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 81: 4, 146, 168, 177 , 178, 179, 184, 185, 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, 279 and the like, among them CI in terms of high brightness and high contrast Pigment Red 177, 254 is preferred.

As an example of a green pigment, C. I. Pigment Green 7, 10, 36, 37, 58, etc. can be used, Among these, C. I. Pigment Green 7, 36, 58 is preferable from a viewpoint of high brightness and high contrast.

Examples of yellow pigments include CI Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 6300 · 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 198, 199, 213, 214 and the like can be used, and among these, CI Pigment Yellow 138, 139, 150 is preferable from the viewpoint of high brightness and high contrast.

As an example of a blue pigment, C. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64 and the like can be used.

As an example of the violet pigment, Violet 23 or the like can be used.

As an example of the cyan pigment, I. Pigment Blue 15: 3 or C. I. Pigment Blue 15: 3 and C. I. Pigment Green 7 may be used.

As an example of the magenta pigment, pigments such as C. I. Pigment Red 81, 81: 1, 81: 2, 81: 3, 81: 4, 122, 192, 202, 207, 209, C. I. Pigment Violet 19 and the like can be used.

In the composition of this invention, dyes other than the said pigment can also be used together. As dyes other than a pigment, dye, a natural pigment, etc. are mentioned.

It is preferable to refine | miniaturize and use the said pigment from a viewpoint of achieving high contrast. As a means for miniaturizing a pigment, a method of mechanically pulverizing a pigment (called a grinding method), a method of dissolving a good solvent in a poor solvent to precipitate a desired micronized pigment (called a precipitation method), and a desired method at the time of synthesis And a method for producing a micronized pigment (called a synthetic precipitation method). According to the synthesis | combining method, chemical property, etc. of the pigment to be used, an appropriate method can be selected and performed with respect to each pigment.

The pigment is preferably included within the range of 5 to 20 wt% based on the total composition.

The ink composition of this invention may further contain the pigment dispersant. The pigment dispersant is added to increase the pigment dispersibility and to prevent reaggregation of the pigment after dispersion.

Since the said pigment dispersant adsorb | sucks on the surface of a pigment using an acidic group or a basic group as an anchor, and the repulsive effect of a polymer acts effectively and expresses maintenance of dispersion stability, it is preferable that it is a polymer which has an acidic group or a basic group.

As an acidic group, a sulfone group is preferable at the point which is excellent in adsorption characteristic, and an amino group is preferable at the point which is excellent in adsorption characteristic as a basic group.

The dispersant having an acidic group or a basic group is preferable because the comb polymer having a structure in which a branched polymer is graft-bonded to a stem polymer having an acidic group or a basic group has more organic solvent solubility due to excellent steric repulsion effect of the branched polymer. Moreover, the comb-tooth type polymer which has the molecular structure which graft-bonded the branch polymer of 2 or more molecules to 1 molecule of stem polymer is preferable for the said reason.

As a commercially available resin type dispersant, Disperbyk-101, 103, 107, 108, 110, 111, 116, 130, 140, 154, 161, 162, 163, 164, 165, 166, 170, 171, 174 made by BIC Chem Corporation , Nippon, 180, 181, 182, 183, 184, 185, 190, 2000, 20O1, or Anti-Terra-U, 203, 204, or BYK-P104, P104S, 220S, or Lactimon, Lactimon-WS or Bykumen, etc. S0LSPERSE-3000, 9000, 13240, 13650, 13940, 17000, 18000, 20000, 21000, 24000, 26000, 27000, 28000, 31845, 32000, 32500, 32600, 34750, 36600, 38500, 41000, 41090 EFKA-46, 47, 48, 452, LP4008, 4009, LP4010, LP4050, LP4055, 400, 401, 402, 403, 450, 451, 453, 4540, 4550, LP4560, etc. 120, 150, 1501, 1502, 1503, etc. are mentioned.

The pigment dispersant is preferably included within the range of 1 to 10 wt% based on the total composition.

The binder resin may be used without limitation a binder resin widely used in the art.

The binder resin is preferably included in 8 wt% or less based on the total composition.

The ink composition of this invention may further contain the thermal initiator which initiates superposition | polymerization of a polymerizable monomer by heat. Specific examples of thermal initiators that may be used in the present invention include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2 ' -Azobis- (4-methoxy-2,4-dimethylvaleronitrile), 2-cyano-2-propylazoformamide, 1,1'-azobis (cyclohexane-1-carbonitrile), 2 , 2'-azobis (2-methylbutyronitrile), V-40, VA-086, VA-085, VF096, VAm-110, Vam-111 (above Wako pure chemicals ind.), Benzoyl peroxide, lau Loyle peroxide, t-butylperoxy pivalate and 1,1'-bis- (bis-t-, butylperoxy) cyclohexane may be used alone or two or more selected from the group consisting of, but is not limited thereto. .

The thermal initiator is preferably included in 1.5 wt% or less based on the total composition.

The polymerizable monomer may be used without limitation in the art, and may exemplify an ethylenically unsaturated monomer including a carboxyl group. As such a monomer, methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, (beta) Carboxyethyl (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate , Trimetholpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,6-hexanediol diglycidyl ether di (meth) acrylate, bisphenol A diglycidyl ether di (meth) ) Acrylate, neopentyl glycol diglycidyl ether di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, ester acrylate, methirol Various acrylic esters and methacrylic esters, such as (meth) acrylic acid ester of melamine, epoxy (meth) acrylate, and urethane acrylate, (meth) acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether , Pentaerythritol trivinyl ether, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-vinylformamide, acrylonitrile, and the like, and these may be used alone or in combination of two or more thereof. Can be used.

The polymerizable monomer is preferably included within the range of 0.5 to 8 wt% based on the total composition. If the content of the polymerizable monomer is less than 0.5 wt%, crosslinking may not be sufficiently performed after the pattern formation of the ink, and thus the desired film strength and chemical resistance properties may not be obtained due to the decrease in curing degree. On the other hand, if the content is more than 8 wt%, it may lead to an increase in viscosity of the ink and a decrease in fluidity.

The ink composition of the present invention may contain an organic solvent. The organic solvent sufficiently disperses the colorant in the transparent resin, and dries the coloring composition of the present invention on a transparent substrate such as a glass substrate on which BM is patterned. It is used to facilitate the formation of the filter segment by jetting the film thickness to be 0.2 to 5 mu m.

As an organic solvent, for example, cyclohexanone, ethyl cellosolve acetate, butyl cellosolve acetate, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, ethyl benzene, ethylene glycol diethyl ether, xylene, ethyl cell Rosolve, methyl-n-amyl ketone, propylene glycol monomethyl ether, toluene, methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol, isobutyl ketone, petroleum solvents, and the like. Used alone or in combination.

The solvent having a boiling point of 180 ° C. or higher plays a role of controlling ink jetting (ejection) by preventing the nozzle part from drying, and has a boiling point of 180 ° C. to 300 ° C., and at the same time, a solvent having a vapor pressure of 0.5 mmHg at room temperature. desirable. Non-limiting examples thereof include ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, and diethylene glycol monoethyl ether acetate. One or more selected from the group consisting of may be used, but is not limited thereto.

The composition of the present invention may further comprise at least one additive selected from a dispersing aid, a storage stabilizer, a curing accelerator, a thermal polymerization inhibitor, a plasticizer, an adhesion promoter, a filler, an antifoaming agent and an anti-agglomerating agent.

The said dispersing aid can use surfactant. Since the dispersion aid is excellent in dispersing the colorant and has a great effect of preventing re-agglomeration of the colorant after dispersion, a color filter having excellent transparency may be used when a colorant composition obtained by dispersing the colorant in the transparent resin using the dispersion aid. Obtained. As surfactant, polyoxyethylene alkyl ether sulfate, sodium dodecylbenzene sulfonate, the alkali salt of a styrene-acrylic acid copolymer, sodium alkylnaphthalin sulfonate, sodium alkyl diphenyl ether disulfonate, lauryl sulfate monoethanolamine, lauryl sulfate Anionic surfactants such as triethanolamine, ammonium lauryl sulfate, monoethanolamine stearate, sodium stearate, sodium lauryl sulfate, and monoethanolamine of styrene-acrylic acid copolymer; Nonionic surfactants such as polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene sorbitan monostearate and polyethylene glycol monolaurate; Cationic surfactants such as alkyl quaternary ammonium salts and ethylene oxide adducts thereof; Amphoteric surfactants, such as alkyl betaine, such as alkyl dimethylamino acetic acid betaine, and alkyl imidazoline, are mentioned, These can be used individually or in mixture of 2 or more types.

The storage stabilizer serves to stabilize the viscosity over time. Examples of the storage stabilizer include organic acids such as quaternary ammonium chloride, lactic acid and oxalic acid, and organic phosphines such as methyl ether, t-butyl pyrocatechol, tetraethylphosphine and tetraphenylphosphine, and phosphite. have.

The curing accelerators, thermal polymerization inhibitors, plasticizers, adhesion promoters, fillers, antifoaming agents, anti-agglomerating agents can be used without limitation in the art.

The additive is preferably added in an amount of 0.01 to 3% by weight based on the total weight of the ink composition.

In the present invention, the viscosity of the ink composition is preferably within the range of 10 to 18 cP, more preferably within the range of 12 to 16 cP. The ink composition may be most easily jetted within the viscosity range.

The composition of the present invention can be prepared by first mixing a pigment, a pigment dispersant, a melamine compound, and further adding and mixing a binder resin, a polymerizable monomer, a thermal initiator and an organic solvent thereto.

Next, the color filter of this invention is demonstrated.

The color filter of this invention is a color filter provided with the filter segment formed from the ink composition for color filters of this invention. The color filter includes two to six color filter segments selected from red, green, blue, magenta, cyan and yellow, and at least one filter segment is formed using the coloring composition of the present invention.

The color filter of this invention can be manufactured by forming the filter segment of each color on a board | substrate by the inkjet printing method using the coloring composition of this invention.

As a board | substrate, the glass plate with high transmittance | permeability with respect to visible light, and resin plates, such as polycarbonate, polymethyl methacrylate, and a polyethylene terephthalate, are used.

Examples of the BM (black matrix) layer formed by the photolithography method include the following method. That is, each color-colored photosensitive composition prepared as the solvent-developed or alkali-developed black resist cured by light irradiation is dried on a transparent substrate by a coating method such as spray coating, spin coating, slit coating or roll coating. Coating is carried out so that the film thickness becomes 0.2-5 micrometers. Ultraviolet exposure is performed to the dried film which passed through prebaking (60-120 degreeC, 30 second-5 minutes) through the mask which has a predetermined pattern provided in the contact or non-contact state with this film. Thereafter, the developer is sprayed with a solvent or an alkaline developer, or sprayed with a spray to remove the uncured portion to form a desired pattern. After that, in order to completely cure the BM portion, a post-baking process (200-230 ° C., 30-60 minutes) is performed. According to such a photolithography method, a highly precise BM portion can be formed.

At the time of image development, aqueous solution, such as sodium carbonate and sodium hydroxide, is used as alkaline developing solution, Organic alkali, such as dimethylbenzylamine and triethanolamine, can also be used. Moreover, an antifoamer and surfactant can also be added to a developing solution.

In addition, in order to increase the ultraviolet exposure sensitivity, after coating and drying the black resist material, a water-soluble or alkali-soluble resin such as polyvinyl alcohol or a water-soluble acrylic resin is applied and dried to form a film to prevent polymerization inhibition by oxygen. After that, ultraviolet light exposure may be performed.

R, G, and B color parts are formed on the glass on which the BM pattern is formed through an inkjet process. After filling each bank by R, G and B, fill the bank, prebaking (3 minutes at 90 ° C) and post-baking (30 minutes at 220 ° C) each time, or jetting R, G, and B simultaneously A prebaking and a postbaking process can be performed. In view of the process, the latter method is more preferable.

Hereinafter, an Example is given and this invention is demonstrated in detail. It is clear that the embodiments in the present specification are for the purpose of detailed description of the invention and are not intended to limit the scope of the patent.

Example  One

Based on 100 parts by weight of the total composition, 3.5 parts of red pigment (R254), 6.2 parts of red pigment (R177), 5.4 parts of pigment dispersant, melamine compound (Cymel 303, a compound represented by the following formula (4) and a polymer mixture thereof) 5.5 The parts were mixed first to prepare a solution in which the pigment was dispersed, and then 0.9 parts of a binder resin (which is a copolymer of benzyl methacrylate, methyl methacrylate, and glycidyl methacrylate), and 2.0 parts of a polymerizable monomer (DPHA). 0.5 parts of a thermal initiator (V-40) and 76 parts of a solvent (BCA) were further added and mixed to prepare a color filter ink for an inkjet process.

[Formula 4]

Example  2

Based on 100 parts by weight of the total composition, 10.2 parts of the red pigment (R254), 5.3 parts of the pigment dispersant, and 7.2 parts of the melamine compound (Cymel 303, the compound represented by Formula 4 and a polymer mixture therebetween) were first mixed to disperse the pigment. After preparing the solution, 0.3 parts of binder resin (which is a copolymer of benzyl methacrylate, methyl methacrylate, and glycidyl methacrylate), 0.9 part of polymerizable monomer (DPHA), thermal initiator (V-40) 0.1 part and 76 parts of solvent (BCA) were further added and mixed to prepare an ink.

Example  3

Based on 100 parts by weight of the total composition, 10.2 parts of a red pigment (R177), 5.4 parts of a pigment dispersant, and 7.1 parts of a melamine compound (Cymel 303, a compound represented by Formula 4 and a polymer mixture therebetween) were first mixed to disperse the pigment. After preparing the solution, 0.3 parts of binder resin (which is a copolymer of benzyl methacrylate, methyl methacrylate, and glycidyl methacrylate), 0.9 part of polymerizable monomer (DPHA), thermal initiator (V-40) 0.1 part and 76 parts of solvent (BCA) were further added and mixed to prepare an ink.

Example  4

A color filter ink for an inkjet process was prepared in the same manner as in Example 1 except for using another melamine compound (Cymel 327, a compound represented by Formula 5 below and a polymer mixture therebetween).

[Formula 5]

Example  5

A color filter ink for an inkjet process was prepared in the same manner as in Example 1 except for using another melamine compound (Cymel 1130, a compound represented by Chemical Formula 6, and a polymer mixture therebetween).

[Formula 6]

Example  6

A color filter ink for an inkjet process was prepared in the same manner as in Example 1 except for using another melamine compound (Cymel 1158, a compound represented by Formula 7 and a polymer mixture therebetween).

[Formula 7]

Comparative example  One

Based on 100 parts by weight of the total composition, 3.5 parts of red pigment (R254), 6.2 parts of red pigment (R177) and 5.4 parts of pigment dispersant were first mixed to prepare a solution in which the pigment was dispersed, followed by binder resin (benzyl methacrylate, 2.7 parts of methyl methacrylate and glycidyl methacrylate), 5.7 parts of a polymerizable monomer (DPHA), 0.5 part of a thermal initiator (V-40), and 76 parts of a solvent (BCA) were added and mixed. Color filter inks for inkjet processes were prepared.

Comparative example  2

Based on 100 parts by weight of the total composition, 10.2 parts of the red pigment (R254) and 5.3 parts of the pigment dispersant were first mixed to prepare a solution in which the pigment was dispersed, followed by binder resins (benzyl methacrylate, methyl methacrylate, and glycidyl). 2.7 parts of a copolymer of methacrylate), 5.7 parts of a polymerizable monomer (DPHA), 0.1 part of a thermal initiator (V-40), and 76 parts of a solvent (BCA) were further added and mixed to prepare an ink.

Comparative example  3

Based on 100 parts by weight of the total composition, 10.2 parts of red pigment (R177) and 5.4 parts of a pigment dispersant were mixed first to prepare a solution in which the pigment was dispersed, and then binder resin (benzyl methacrylate, methyl methacrylate, and glycidyl). 2.6 parts of a copolymer of methacrylate), 5.7 parts of a polymerizable monomer (DPHA), 0.1 part of a thermal initiator (V-40), and 76 parts of a solvent (BCA) were further added and mixed to prepare an ink.

Experimental Example

Contrast ratio measurement experiments were carried out on the Examples and Comparative Examples as follows. The results were shown in Tables 1 and 2 below.

* Contrast Ratio Measurement Method

Ink was applied to the washed glass, prebaked at 90 ° for 3 minutes, and postbaked at 220 ° C. for 30 minutes to completely cure the ink. The contrast ratio of each sample which passed through the obtained ink coating film (thickness 1-2 micrometers) only to the prebaking and the postbaking was measured.

Ink composition Contrast ratio after prebaking Contrast ratio after postbaking Viscosity (cP) Example 1 Red pigment (R254, R177), Melamine compound (cymel 303) added 6,234 5,798 12.8 Example 2 Red pigment (R254), melamine compound (cymel 303) added 4,088 3,553 15.6 Example 3 Red pigment (R177), melamine compound (cymel 303) added 7,454 7,553 12.7 Comparative Example 1 No Melamine Compound Added in Example 1 6,051 5,317 16.3 Comparative Example 2 No Melamine Compound Added in Example 2 4,053 3,313 16.2 Comparative Example 3 No Melamine Compound Added in Example 3 6,908 6,691 13.8 * Contrast ratio: luminance value when the upper and lower polarizers are vertical / luminance value when the upper and lower polarizers are horizontal

Ink composition Weight average molecular weight of melamine compound Contrast ratio after postbaking Viscosity (cP) Example 1 Red pigment (R254, R177), Melamine compound (cymel 303) added 585 5,798 12.8 Example 4 Red pigment (R254, R177), Melamine compound (cymel 327) added 509 6,022 14.5 Example 5 Red pigment (R254, R177), Melamine compound (cymel 1130) added 1,137 5,707 13.8 Example 6 Added red pigment (R254, R177), melamine compound (cymel 1158) 2,881 5,522 12.6 * Contrast ratio: luminance value when the upper and lower polarizers are vertical / luminance value when the upper and lower polarizers are horizontal

* Method for measuring molecular weight of melamine compound

Typically, GPC (Gel Permeation Chromatography) was widely used for molecular weight measurement. The solvent used was THF (TetraHydroFuran), and the standard was polystyrene.

The molecular weight measurement results of the melamine compound used in the examples were as shown in Table 3 below.

Split integral Total integral cymel 303 1,295 / 583/293 585 cymel 327 1,115 / 601/311 509 cymel 1130 2,060 / 789/416 1,137 cymel 1158 4,083 / 952/548 2,881

As shown in Table 1, it can be seen that the contrast ratio is improved when the melamine compound is added. In particular, when the melamine compound is added, it was found that the effect of preventing the contrast ratio decrease after the post-baking is great. For example, after the post-baking, the contrast ratio tends to decrease a little. In Example 1, the contrast ratio decreases after the post-baking is about 430, whereas the comparative example 1 shows that the decrease is larger than about 730. Could.

In addition, as shown in Table 2, it was confirmed that the effect is somewhat different depending on the weight average molecular weight of the melamine compound. In particular, it was found that the weight-average molecular weight of the melamine compound is more advantageous for improving the contrast ratio when the weight average molecular weight is around 500.

Claims (9)

In the ink composition for color filters containing a pigment, binder resin, and a polymerizable monomer, It further comprises a melamine compound, The melamine compound is a weight average molecular weight in the range of 126 ~ 5000, the ink composition for a color filter, characterized in that it comprises at least one of a compound represented by the formula (1), and polymers therebetween. [Formula 1]

(Wherein the _{R 1, R 2, R 3} , R 4, R 5 and R ₆ independently of one another are each hydrogen, C _{1 -6} alkyl, C _{1 -6} alkoxy group, a carboxyl group, C _{1 -6} of the refers to a compound containing an ether group, an alcohol group in the C _{1 -6,} an amino group, a nitro group, a hydroxyl group, a phenyl group or an acrylic group) The ink composition of claim 1, wherein the compound represented by Chemical Formula 1 is a compound represented by the following Chemical Formula 2. [Formula 2]

Where R _1a , R _2a and R _3a They are each independently of each other by means a hydrogen, an alkyl group or a (meth) acrylate of a C _{1 -6)} The ink composition of claim 1, wherein the compound represented by Chemical Formula 1 is a compound represented by Chemical Formula 3. (3)

Wherein R _1b , R _2b , R _3b , R _4b , R _5b and R _6b They are each independently of each other by means a hydrogen, an alkyl group or a (meth) acrylate of a C _{1 -6)} The ink composition of claim 1, wherein the compound represented by Chemical Formula 1 is one of the compounds represented by the following Chemical Formulas 4 to 7.

The ink composition of claim 1, wherein the melamine compound is included in a range of 1 to 20 wt% based on the total composition. The method of claim 5, further comprising a pigment dispersant, wherein the pigment is 5 to 20 wt% based on the total composition, the pigment dispersant is contained in the range of 1 to 10 wt%, the polymerizable monomer within 0.5 to 8 wt% An ink composition for color filters. The ink composition for color filters of claim 1, further comprising an additive. The ink composition of claim 1, wherein the ink composition has a viscosity of 10 to 18 cP. A color filter prepared from the ink composition of claim 1.