KR20060109624A - Offset ink composition for color-filter - Google Patents

Abstract

Provided is an offset ink composition for a color filter, which shows a high production yield and excellent transfer property when fabricating a color filter via a simple offset printing process with a high printing rate. The offset ink composition for a color filter comprises a resin, a pigment and a solvent and further comprises a phenolic resin represented by the following formula 1. In the formula 1, R is a group represented by the formula of -CHl(CH3)m, wherein each of l and m is a number of 0-3, with the proviso that l+m is 3, and n is an integer of 2-150. The phenolic resin is used in an amount of 2-40 wt% based on the total weight of the ink composition.

Description

Offset ink composition for color filters

The present invention relates to an ink composition for producing a color filter by an offset printing method, and more particularly, to an offset ink composition using a resin for improving transferability.

In general, color filters are manufactured by coating fine regions colored in three or more colors on a transparent substrate as an indispensable component of the liquid crystal panel. Compared with the CRT, the display device is small in size and equivalent in performance to that of the CRT, and has been replaced by the CRT as a television screen, a personal computer screen, and other display devices. Such colored thin films are produced by dyeing, printing, electrodeposition, pigment dispersion, or the like.

In recent years, the LCD market is steadily increasing, requiring production volume and cost reduction. As a result, production efficiency and economic efficiency are further required. Currently, color filters for LCDs use a spin coater, a roll coater, or the like to apply a photosensitive colored resin composition dispersed in various photosensitive compositions to form a coating film, and then the pattern is exposed to a pattern to develop colored pixels. The preparation by the pigment dispersion method which obtains is common. In the pigment dispersion method, it is converted from spin-coating to spinless-coating in order to improve economic efficiency and production efficiency. However, it is necessary to repeat the exposure-developing process for red, green, and blue, which leads to high consumption, high manufacturing cost, and high production efficiency. There is a limit to. Accordingly, there is a growing demand for a printing method using an ink jet printer, a printing method or a dyeing method using a printing machine capable of forming patterns of various colors at once without an exposure-developing process.

Until now, methods for producing ink compositions for color filters used in printing presses have been proposed, but in the ink jet method, a binder using an condensation reaction of an amino compound and an aldehyde compound is mainly used, and a low viscosity and low boiling point solvent is mainly used. It is content. In particular, Korean Patent Laid-Open Publication No. 2002-0025037 introduces a binder using a condensation reaction between an amino compound and an aldehyde compound including a carboxyl group and / or phenolic hydroxyl group, and a method using a solvent having a boiling point of 80 to 200 ° C. In the gravure method in the printing press, the thermosetting type mainly using melamine resin and hardener is the main content.

In the ink composition using a melamine resin in the offset printing machine method, there is a problem of high and low roughness occurring on the surface. The method of suppressing the high and low difference of the rough surface which generate | occur | produces on the printing ink surface by adding an epoxy resin was devised. However, the printing plate needs to be cleaned frequently in the process and there is a limit to the precision of the pattern.

Conventional offset printing method ink composition has a problem that the pattern is transferred to the transparent substrate in the blanket (blanket) is a problem that must be frequently cleaned.

Accordingly, an object of the present invention is to provide an ink composition having a high production yield and excellent transferability in manufacturing a color filter by a printing method using a quick offset printing method.

The ink composition of the offset for the color filter of the present invention for achieving the above object is characterized in that it further comprises a phenol resin represented by the following formula, comprising a resin, a pigment and a solvent.

Formula 1

Wherein R is represented by -CH ₁ (CH ₃ ) _m , where l and m are 0-3 and l + m satisfies 3, and n is an integer from 2 to 150.

The present invention will be described in more detail as follows.

The ink composition according to the present invention contains, as a main component, a solvent, a pigment dispersed in the solvent, a curable resin and a resin for improving transferability.

The compounding component used for the color filter inkjet ink composition of this invention and the method of using this composition are demonstrated.

In the ink composition of the present invention, the thermosetting resin uses melamine or epoxy resin. Melamine-based resins are thermosetting resins made by reacting melamine with formaldehyde. Melamine has three amino groups and six functional groups that react with formaldehyde. Depending on the mixing ratio and the reaction conditions, a mixture of polymethylolmelamine containing many methylol groups (HOCH ₂ ) — or (CH ₂ ) n (OH) n — is obtained. It causes condensation reaction between other OH groups, crosslinks, and hardens. As the melamine resin used in the present invention, a known commercially available resin can be used.

The content of such melamine resin or epoxy resin is preferably 2 to 50% by weight of the total ink composition. If the content is less than 2% by weight, there is a problem in that the coating film is not formed well. Due to this, there may be a problem in the thickness variation of the coating film and the process of the printing press.

In the ink composition of the present invention, the phenolic resin is mixed with the above resin and used as the resin for improving the transferability. At this time, the resin to improve the transferability should be high compatibility with the solvent, the adhesion to the transparent substrate should be better than the adhesion to the blanket (blanket). For this reason, in the present invention, it is preferable to use a resol type of the phenolic resin.

The phenolic resin of the resol type refers to a phenolic resin having a higher content of formaldehyde, with a composition ratio of phenol and formaldehyde of 1: 1.5 to 1.6. Specific structure is as represented by the formula (1).

The content of such phenolic resin is preferably 2 to 40% by weight of the total ink composition. If the content is less than 2% by weight, there is a problem of poor transfer, and when the content is more than 40% by weight, the thickness of the coating film is not constant. It may not, there is a problem that the projection occurs.

As a dye or pigment which can be used for this invention, 1 type, or 2 or more types of conventionally well-known various dyes and pigments can be used. In addition, since the pigment is preferably high transmittance, it is preferable to use the smallest possible particles. Preferably, the pigment having an average particle diameter of 0.01 to 0.2 탆, more preferably 0.01 to 0.05 탆 is preferable.

Examples of the inorganic pigments include metal oxides such as iron, cobalt, aluminum, cadmium, lead, copper, titanium, antimony, zinc, chromium and magnesium, and complex oxides of the above metals. As an organic pigment, it can illustrate with a color index. Specifically, C.I. Pigment Yellow 11, 24, 31, 53, 83, 93, 99, 108, 109, 110, 138, 139, 147, 150, 151, 154, 155, 167, 180, 185, 199; C.I. Pigment Orange 36, 38, 43, 71; C.I. Pigment Red 81, 105, 122, 149, 150, 155, 171, 175, 176, 177, 209, 220, 224, 242, 254, 255, 264, 270; C.I. Pigment Violet 19, 23, 32, 39; C.I. Pigment Blue 1, 2, 15, 15: 1, 15: 3, 15: 6, 16, 22, 60, 66; C.I. Pigment Green 7, 9, 36, 37; C. I. Pigment Brown 25, 28; C.I. Pigment Black 1, 7, etc. can be illustrated.

The content of such a pigment is preferably 1 to 49% by weight of the total ink composition. If the content is less than 1% by weight, there is a problem in that the desired chromaticity cannot be exhibited. There may be a problem.

As the solvent used in the present invention, ethers and alkylene glycol (alkyl ether) alkylates having high compatibility with other materials used for color filter production are preferable.

Specific examples of the ethers include diethylene glycol butyl ether, diethylene glycol hexyl ether, diethylene glycol dibutyl ether or dipropylene glycol tertiary butyl ether. Specific examples of the alkylene glycol (alkyl ether) alkylates include ethylene glycol butyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol dibenzoate and the like.

It is also possible to use together with the following low boiling point solvents from a viewpoint of solubility, reactivity with each component, and convenience of coating film formation: diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol methyl ether acetate; Ketones such as methyl ethyl ketone, cyclohexanone and 4-hydroxy-4-methyl-2-pentanane; Methyl, ethyl, propyl, butyl ester of acetic acid, ethyl of 2-hydroxypropionic acid, methyl ester, ethyl ester of 2-hydroxy-2-methylpropionic acid, methyl, ethyl, butyl ester of hydroxyacetic acid, ethyl lactate, lactic acid Ethyl, propyl lactate, butyl lactate, methyl of methoxyacetic acid, ethyl, propyl, butyl ester, methyl of ethyl propoxy, ethyl, propyl, butyl ester, methyl of methyl butoxy, ethyl, propyl, butyl ester, 2-methic Methyl, ethyl, propyl, butyl ester of oxypropionic acid, methyl, ethyl, propyl, butyl ester, methyl of ethoxypropionic acid, methyl, ethyl, propyl, butyl ester of 2-butoxypropionic acid, methyl of 3-methoxypropane, S, such as ethyl, propyl, butyl ester, methyl of 3-ethoxy propionic acid, ethyl, propyl, butyl ester, methyl of 3-butoxy propionic acid, ethyl, propyl, butyl ester, etc. It may be the reuryu.

Such a solvent is used so that the total solid concentration is 10 to 50% by weight. If the total solid concentration of the ink composition is less than 10% by weight, there may be a problem in that a coating film is not formed due to low viscosity. This is because there may be a problem that the thickness of the coating film is not constant.

On the other hand, the composition of this invention can mix | blend various additives other than the said component, such as surfactant, a dispersing agent, etc. as needed in the range which does not violate the objective of this invention.

Surfactants are intended to improve applicability and wettability during the development process. Specifically, phthalocyanine derivatives of Mority City Bridge, organosiloxane polymers of Shin-Etsu Chemical Co., Ltd. (KP322, KP323, KP340, KP341), 3M Silicone surfactants, such as the fluorine derivative (FC-129, FC-170C, FC-430; F-172, F-173, F-183, F-470, F-475) of DIC Corporation and DIC Corporation, are mentioned. Such surfactant may be used in an amount of preferably 5 parts by weight or less, more preferably 2 parts by weight or less, based on 100 parts by weight of the resin. When the amount of the surfactant exceeds 5 parts by weight, bubbles are likely to occur during application.

The dispersing agent used by this invention does not have limitation in particular, A well-known conventional dispersing agent can be used. Examples of such dispersants include intermediates of pigments, intermediates of dyes, surfactants and resin type dispersants such as polyethylene, acrylic, polyester, polyamide and polyurethane compounds.

As a commercial item of the said resin type dispersing agent, "Disperbyk-160 family" "Disperbyk-170 family" etc. by a BYK Chemie company are mentioned, for example.

The color filter may be prepared by forming the color filter pattern on the transparent substrate in an offset manner and then thermosetting the composition. If the transparent substrate used by this invention is a transparent substrate used for a color filter, and can be used as long as it is excellent in heat resistance, a glass substrate etc. are mentioned, for example.

Examples of the offset method used in the present invention include a gravure or reverse method.

In order to form a coloring pattern, first, a pattern is formed on a blanket by the offset method of the ink composition used by this invention on the transparent substrate provided with the black matrix, and what is necessary is just to transfer a coloring pattern to a board | substrate.

Thermosetting can use well-known conventional heat sources, such as a hotplate and an electric oven. The heating temperature is preferably in the range of 200 to 300 ° C. If it is less than 200 ° C, evaporation and thermal curing of the solvent are insufficient, so that the film strength and chemical resistance tend to be poor. If the temperature is over 300 ° C, excessive shrinkage of the pixel portion may cause problems in substrate adhesion and precision.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited to the Examples. The following method was used for the performance evaluation about the created coating film.

1) Transcription evaluation

The composition was evaluated to the extent that the colored pattern patterned on the blanket by a printing machine was transferred to the transparent substrate and remained on the blanket.

○: When all 100 pieces of 100 pieces are left

×: If any one of 100 pieces remain

2) adhesion evaluation

3M Tape No. Cross-cut tests were performed using 810, 0.5 inch.

○: 100 out of 100 pieces remain intact

×: If one out of 100 pieces fall or there is an abnormality

Example 1 and Comparative Examples 1 and 2

Next, propylene glycol methyl acetate was added to the resin and the pigment as shown in Table 1 so as to have a total solid concentration of 18% by weight, and the composition was mixed. In Table 1, a unit is weight%.

Example 1 Comparative Example 1 Comparative Example 2 Suzy Melamine resin 26.1 36.1 26.1 Epoxy resin - 10.0 Acrylic resin - - - Phenolic resin 10.0 - - Blue pigment 15.0 15.0 15.0 Phenolic resin: Phenolic resin represented by general formula (1)

The composition of Example 1 and Comparative Examples 1-2 was evaluated by the said color filter manufacturing method and evaluation method. The results are shown in Table 2 below.

Furtherance Evaluation item Transcription Adhesion Example 1 ○ ○ Comparative example One × ○ 2 × ○

As described in detail above, the ink composition obtained by further comprising a phenolic resin according to the present invention can increase the production yield when the color filter is produced by the printing method through the offset method and also excellent transferability.

Claims (3)

In the ink composition of the inkjet for color filters containing a resin, a pigment and a solvent, The ink composition of the offset for the color filter, characterized in that it further comprises a phenol resin represented by the following formula (1). Formula 1

Wherein R is represented by -CH ₁ (CH ₃ ) _m , where l and m are 0-3 and l + m satisfies 3, and n is an integer from 2 to 150. According to claim 1, wherein the ink composition of the offset for the color filter, characterized in that it comprises 2 to 40% by weight of the phenol resin represented by the formula (1). The color filter obtained by spraying the ink composition of Claim 1 by the inkjet system.