KR20100090305A - Process for producing liquid crystal display apparatus - Google Patents

Abstract

The present invention eliminates the need for a special ultraviolet irradiation device and at the same time provides an LCD manufacturing method by a simple liquid crystal dropping method with high accuracy. The method of this invention is a method of manufacturing the liquid crystal display device which has a liquid crystal layer between a 1st board | substrate and a 2nd board | substrate by the liquid crystal dropping method, (a) contains an epoxy resin and a latent hardening | curing agent, Applying a thermosetting resin composition having a gelation time of 3 minutes or less to a sealing region surrounding the periphery of the surface of the first substrate; (b) a liquid crystal in a central region on the center side of the sealing region of the surface of the first substrate; It is characterized by including the step of dropping, (c) the step of superposing the second substrate on the first substrate, and (d) a heating step of curing the thermosetting resin composition.

Description

Manufacturing method of liquid crystal display device {PROCESS FOR PRODUCING LIQUID CRYSTAL DISPLAY APPARATUS}

TECHNICAL FIELD This invention relates to the manufacturing method of the liquid crystal display device using the liquid crystal dropping method. Specifically, It is related with the manufacturing method which performs the main sealing of a board | substrate peripheral part using a thermosetting resin composition.

Conventionally, when assembling a relatively small liquid crystal display (hereinafter, referred to as an LCD), a transparent substrate having two electrodes is opposed to each other at a predetermined interval, and the surroundings are sealed and sealed with a sealing agent. The liquid crystal was injected into the cell from the liquid crystal injection hole provided in the one part, and this liquid crystal injection hole was produced by sealing using a sealing agent.

In recent years, as large LCDs have become widespread, various problems, such as poor productivity, have occurred due to the very long time required for the injection of liquid crystals.

Therefore, the manufacturing method of LCD called a one drop fill process (ODF) is examined and put into practical use as an efficient manufacturing method of a large size LCD. In this method, first, a rectangular sealing pattern is formed on one side of a transparent substrate having two electrodes by screen printing or the like. Subsequently, microdroplets of liquid crystal are applied dropwise into the sealing frame on the transparent substrate in the state of the sealant uncured state, and the other transparent substrate is overlapped, and then the sealant is cured to produce an LCD. By bonding the substrates under reduced pressure, an LCD can be produced efficiently.

The sealing agent used for a liquid crystal dropping method is ultraviolet curing type or the ultraviolet-heat combined use curing type (refer patent document 1). In the combined type of ultraviolet rays and heat, the two substrates are superimposed, the sealant is cured in a short time to the extent that positional shift or the like does not occur by ultraviolet irradiation, and then further heated to thermally harden the sealant to final strength. However, when the size of LCD becomes larger, a special ultraviolet irradiation apparatus is needed, and also the countermeasure against deterioration of members, such as a liquid crystal and an alignment film by ultraviolet rays, is also needed.

On the other hand, a thermosetting resin, for example, a one-component type thermosetting epoxy resin composition, has excellent performance and is easy to handle, and is used in various applications. For example, it is used for the assembly and mounting of precision components, such as an image sensor packaging, an image sensor module assembly, an optical device attachment, and LCD main sealing (a conventional liquid crystal suction method).

However, in the thermosetting resin composition, at the time of heating for hardening, since a resin viscosity falls rapidly before hardening, position shift may arise. In the dropping method, a slight time delay occurs while the thermosetting resin is completely cured in the thermosetting process. During this time, the liquidity of the liquid thermosetting resin increases by heating, and the shape of the sealing portion collapses or under reduced pressure. There is a problem that the liquid crystal leaks due to the formation of a sealing part. For this reason, the liquid crystal dropping method which uses a thermosetting resin composition is not currently utilized.

Therefore, in patent document 2, it is described to contain microparticles | fine-particles of acryl-type microparticles | fine-particles and a sugar compound derivative as a gelling agent (patent document 2, paragraph 0021, etc.). According to this document, it is described that fluidity at high temperature can be reduced by adding a gelling agent. However, although the gelling agent mentioned in patent document 2 is considered to be a simple solid particle and functions to lower fluidity, it is not a material for promoting the gelation reaction. And it remains in hardened | cured material and affects the physical property.

Therefore, it is very useful to provide a method that can utilize the excellent properties (for example, durability and reliability) of a thermosetting resin without using such a gelling agent.

Japanese Patent Laid-Open No. 2002-342947 Japanese Patent Laid-Open No. 2005-308811

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing an LCD by a liquid crystal dropping method, which does not require a special ultraviolet irradiation device, is precise, simple, and excellent in durability.

The present invention relates to the following matters.

1. A method of manufacturing a liquid crystal display device having a liquid crystal layer between a first substrate and a second substrate by a liquid crystal dropping method,

(a) applying a thermosetting resin composition containing an epoxy resin and a latent curing agent and having a gelation time at 100 ° C. of 3 minutes or less to a sealing region surrounding the substrate surface at the periphery of the first substrate surface,

(b) dropping a liquid crystal onto a central region surrounded by the sealing region on the surface of the first substrate,

(c) superposing the second substrate on the first substrate, and

(d) Heating step of curing the thermosetting resin composition

Characterized by having a.

2. The said (c) superposition process is performed in the state in which the said thermosetting resin composition has fluidity, and then, it heats at the said (d) heating process, The method of said 1 characterized by the above-mentioned.

3. The method according to the above 1, wherein the (d) heating step is started before the step of (c) overlapping is completed.

4. The method according to any one of 1 to 3 above, wherein the thermosetting resin composition further contains an additive selected from the group consisting of fillers, thixotropic imparting agents and silane coupling agents.

5. Said epoxy resin contains epoxy resin selected from the group which consists of a bisphenol-type epoxy resin, a novolak-type epoxy resin, and a biphenyl-type epoxy resin, The method in any one of said 1-4 characterized by the above-mentioned.

6. Said latent hardener is chosen from modified amine latent hardener, The method in any one of said 1-5 characterized by the above-mentioned.

7. It contains epoxy resin and latent hardener, and gelation time in 100 degreeC shows three minutes or less, The thermosetting resin composition for liquid crystal dropping methods used by the method of said 1 characterized by the above-mentioned.

According to the LCD manufacturing method by the liquid crystal dropping method of this invention, LCD can be manufactured simply, without the need of a special ultraviolet irradiation apparatus, and maintaining the precise position alignment precision, without a position shift. And since epoxy thermosetting resin which is excellent in durability and reliability can be used as a sealing agent, it is excellent in LCD, especially the durability and reliability of the sealing part.

In general, the manufacturing method of the present invention,

(a) applying a liquid thermosetting resin composition to a sealing region surrounding the substrate surface at the periphery of the first substrate surface,

(b) dropping a liquid crystal onto a central region surrounded by the sealing region on the surface of the first substrate,

(c) superposing the second substrate on the first substrate, and

(d) Heating step of curing the thermosetting resin composition

Has

The first substrate and the second substrate used in the present invention are usually transparent glass substrates. Generally, transparent electrodes, active matrix elements (TFTs, etc.), alignment films, color filters, and the like are formed on at least one side of two substrates facing each other, which can be changed in configuration depending on the type of LCD. . It is believed that the manufacturing method of the present invention is applicable to all types of LCDs.

In a process (a), the thermosetting resin composition which is a sealing agent is apply | coated in frame shape to the periphery of one board | substrate and the surface (opposing surface with another board | substrate) of a 1st board | substrate around the board | substrate. In addition, the location which apply | coats a sealing agent in frame shape in this way is called sealing area. The thermosetting resin composition can be apply | coated by well-known methods, such as screen printing and dispensing, as a liquid so that application | coating is possible at least at this time. The sealing area is generally rectangular in the form of a frame, and the display portion of the LCD is provided in the central area in the sealing area. Therefore, the "peripheral part" in which the sealing area is set generally means the outer side of the display part of the LCD, and does not necessarily mean the end of the substrate. On the surface of the substrate, there may be a space in which an electrode and an electric / electronic device for driving the LCD are provided outside the sealing region.

Next, in a process (b), a liquid crystal is dripped at the center area | region enclosed by the frame-shaped sealing area of the 1st board | substrate surface. This process is preferably carried out under reduced pressure.

Next, in a process (c), the said 2nd board | substrate is superimposed on a said 1st board | substrate, In a process (d), it heats and hardens a thermosetting resin composition, and completes sealing. This completes the main part of the LCD panel.

Heating of a process (d) is performed in order to harden a thermosetting resin composition. In one Embodiment of this invention, a process (c) and a process (d) are performed in order. That is, a superposition | polymerization process (c) is performed in the state which has a fluidity | liquidity of a thermosetting resin composition, Then, it heats in a heating process (d), and the said composition gelatinizes and hardens.

However, if bonding of a 1st board | substrate and a 2nd board | substrate is possible, the process (c) which superimposes a said 2nd board | substrate on a 1st board | substrate may be performed in the state in which the fluidity | liquidity of the thermosetting resin composition fell slightly. That is, it is also possible to start the heating step of step (d) before step (c) is completed. However, it is always after process (c) that a composition hardens | cures finally in process (d).

The hardening of the step (d) is generally heated by a heating profile such that the maximum temperature is preferably up to 150 ° C, more preferably up to 130 ° C. The heating time is appropriately selected, for example 3 hours or less, preferably 2 hours or less, more preferably 1.5 hours or less (typically 1 hour).

The thermosetting resin composition used for this invention is characterized by the rapid progress of gelatinization by heating. That is, in this invention, hardening advances before a viscosity falls by temperature rise, and the composition which selects the state which immediately reaches the state without fluidity is selected. In this invention, since the viscosity of a thermosetting resin composition does not have a sharp fall, there exists no position shift of two board | substrates, and the positional relationship of two board | substrates is fixed at the initial stage of heating.

The thermosetting resin composition used by this invention is a thermosetting resin composition which contains an epoxy resin and latent hardening | curing agent specifically, and the gelation time in 100 degreeC shows 3 minutes or less. The progress of hardening of a thermosetting resin composition can be confirmed by sticking a wooden stick into a composition (heating) and lifting up during a heating. In the initial state, the composition is a liquid, and even though the stick is brought into contact with the composition, the seal is not formed. However, when the curing proceeds and the fluidity disappears and the adhesiveness increases, the seal is formed when the stick is lifted up. The state which formed the yarn of about 2-3 cm is made into gelation time.

In the thermosetting resin composition used in the present invention, when the composition is placed at 100 ° C., when the gelation time is less than 3 minutes, curing proceeds competitively with a decrease in viscosity due to a temperature rise, and thus a low viscosity at which position shift occurs. Do not. The gelling time at 100 ° C. is more preferably within 2 minutes, most preferably within 1 minute.

For this reason, a viscosity does not fall sharply from an initial viscosity in the heating profile for hardening of a thermosetting resin composition.

The thermosetting resin composition used for this invention can be obtained by selecting suitably an epoxy resin, a latent hardening | curing agent, and the component added arbitrarily as needed so that it may have said predetermined gelling time. In this invention, it is not necessary to contain the gelling agent prescribed | regulated by the above-mentioned patent document 2 (Unexamined-Japanese-Patent No. 2005-308811 method).

It is preferable that the epoxy resin contained in a thermosetting resin composition has an epoxy resin which has an aromatic ring as a main component, and especially a component (a): 50% or more (by weight) of a thermosetting resin component, Preferably it is 70% or more, Especially preferably, it is 90% or more, and it is also preferable that it is 100%. As needed, you may contain the epoxy resin which does not have an aromatic ring.

As an epoxy resin which has an aromatic ring, Bisphenol-type epoxy resins, such as bisphenol-A epoxy resin, bisphenol F-type epoxy resin, and bisphenol S-type epoxy resin; Novolak-type epoxy resins, such as a phenol novolak-type epoxy resin and a cresol novolak-type epoxy resin; Biphenyl type epoxy resins, such as the brand name YX4000 by Japan Epoxy Resin Co., Ltd., etc. are mentioned. The epoxy resin which has an aromatic ring usually has one or more epoxy groups in a molecule | numerator, and epoxy equivalent can be selected suitably.

As the epoxy resin not having an aromatic ring, an alicyclic epoxy resin having an epoxy group having a ring modification such as a cyclohexene oxide structure and a cyclopentene oxide structure in a molecule (for example, the following formulas (1) to (5) Compound shown)

; Hydrogenated bisphenol type epoxy resins (hydrogenated benzene rings of bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol S type epoxy resins); Dicyclopentadiene type epoxy resins such as glycidyl ether of dicyclopentadiene phenol novolac; Aliphatic alkyl mono- or di-glycidyl ethers such as cyclohexanedimethanol diglycidyl ether, butylglycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether; Alkyl glycidyl esters such as glycidyl methacrylate and tertiary carboxylic acid glycidyl esters; Styrene oxide; Aromatic alkyl monoglycidyl ethers such as phenylglycidyl ether, cresyl glycidyl ether, p-s-butylphenyl glycidyl ether and nonylphenyl glycidyl ether; Tetrahydrofurfuryl alcohol glycidyl ether and the like.

Moreover, the other well-known diluent may be contained in the epoxy resin component.

The latent hardener contained in the thermosetting resin composition used by this invention hardens an epoxy resin when it heats. The latent curing agent suitably selects one or more types of commercially available latent curing agents so that the gelation time at 100 ° C. of the thermosetting resin composition is 3 minutes or less, and also considers the epoxy equivalent of the epoxy resin in terms of potential It is preferable to set the addition amount of a hardening | curing agent suitably.

Specifically, the latent curing agent which is preferably contained in the thermoplastic resin composition used in the present invention is preferably a heat-curable latent curing agent, and particularly preferably a fine powder-based modified amine-based or modified imidazole-based latent curing agent, and further modified. An amine latent hardener is preferable, and the modified amine latent hardener containing active hydrogen is the most preferable. The modified amine-based and modified imidazole-based latent curing agents have a core-shell type in which the surface of the core of the amine compound (or amine adducts) is surrounded by the shell of the modified amine (surface adducts, etc.). Hardeners and masterbatch type hardeners in which they are mixed with an epoxy resin.

As an example of the amine compound which has a heat-hardening type | mold potential, Aromatic first amines, such as diamino diphenylmethane and diamino diphenyl sulfone;

2-heptadecylimidazole, 1-cyanoethyl-2-undecyl imidazolium trimellit, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl- S-triazine, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-phenylimidazolium isocyanurate, 2-phenyl-4-methyl-5-hydroxymethylimidazole, etc. Imidazoles;

Boron trifluoride-amine complex;

Dicyandiamide and derivatives of dicyandiamide such as o-tolyl biguanide and α-2,5-methyl biguanide;

Organic acid hydrazides such as succinic acid dihydrazide and adipic acid dihydrazide;

Diaminomaleonitrile and its derivatives;

Melamine derivatives, such as a melamine and diallyl melamine, are mentioned.

The modified amine latent curing agent is obtained by finely powdering a solid reaction product of an amine compound with an epoxy compound, an isocyanate compound, and a urea compound. The modified imidazole-based latent curing agent is usually obtained by fine powdering the solid reaction product obtained by the adduct reaction of the imidazole compound and the epoxy resin.

As a typical example of a commercially available modified amine latent curing agent, for example, "ADECA HARDNER EH-3615S" (trademark of ADEKA), "ADECA HARDNER EH-4070S" (trademark of ADEKA) , "ADEKA HARDNER EH-4357S" (trademark of ADEKA), "Azicure MY-24" (trademark of Ajinomoto Co., Ltd.), "Fujicure FXE-1000" (Fuji Kasei Kogyo Co., Ltd.) Trademarks), "Fujicure FXR-1036" (trademark of Fuji Kasei Kogyo Co., Ltd.), "Aradur" 939 (trademark of "Huntsman Advanced Materials"), and the like.

As a representative of the commercially available modified imidazole-based latent curing agent, "adeka hardener EH-3293S" (trademark of ADEKA), "adeka hardener EH-4344S" (trademark of ADEKA), "Aji Cure PN-23 "(trademark of Ajinomoto Co., Ltd.)," cure duct P-505 "(trademark of Shikoku Kasei Kogyo Co., Ltd.), and Sanamide LH-210 (trademark of Air Products Co., Ltd.).

In addition, the core-shell curing agent may further treat the surface of the amine compound (or amine adducts) with, for example, acidic compounds such as carboxylic acid compounds and sulfonic acid compounds, isocyanate compounds, epoxy compounds and the like. It is a shell of modified products (adducts, etc.). In addition, the masterbatch type hardener is a state in which the core-shell type hardener is mixed with an epoxy resin.

As a commercially available masterbatch type hardening | curing agent, "Novacure HX-3722" (trademark of Asahi Kasei epoxy), "Novacure HX-3742" (trademark of Asahi Kasei epoxy), "Nobacure HX-3613 "(Asahi Kasei Epoxy Co., Ltd.) etc. are mentioned.

Even if not mentioned above, if it can be combined with an epoxy resin so that the gelling time in 100 degreeC may be 3 minutes or less, it can be used for this invention.

In the thermosetting resin composition, the ratio of the epoxy resin and the latent curing agent can be appropriately set according to the type of the latent curing agent. For example, the latent curing agent is 0.5 to 500 parts by weight, preferably 100 parts by weight of the epoxy resin. Is 2 to 200 parts by weight.

The thermosetting resin composition may further contain an additive, a resin component, and the like in order to improve or change properties such as fluidity, coating properties, storage properties, curing properties, and physical properties after curing.

Examples of components that may be contained as necessary include organic or inorganic fillers, thixotropic imparting agents, silane coupling agents, diluents, modifiers, colorants such as pigments and dyes, surfactants, storage stabilizers, plasticizers, lubricants, antifoaming agents. Although a leveling agent etc. are mentioned, It is not limited to these. It is preferable to contain the additive chosen especially from the group which consists of a filler, a thixotropic imparting agent, and a silane coupling agent.

Although it does not specifically limit as a filler, For example, silica, diatomaceous earth, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, barium sulfate, gypsum, calcium silicate, talc, glass Inorganic fillers such as beads, mica active clay, bentonite, aluminum nitride, silicon nitride, and the like.

Although it does not specifically limit as a thixotropic imparting agent, For example, talc, fine silica, ultra fine surface-treated calcium carbonate, fine alumina, plate-shaped alumina; Layered compounds such as montmorillonite; Acicular compounds, such as aluminum borate whisker, etc. are mentioned. Among them, talc, fine silica, fine alumina and the like are preferable.

Although it does not specifically limit as a silane coupling agent, (gamma) -aminopropyl triethoxysilane, (gamma)-mercaptopropyl trimethoxysilane, (gamma)-methacryloxypropyl trimethoxysilane, (gamma)-glycidoxy propyl trimethoxysilane, SH6062, SZ6030 (above, Toray Dow Corning Silicone Co., Ltd.), KBE903, KBM803 (above, Shin-Etsu Silicone Co., Ltd.), etc. are mentioned.

Moreover, the thermosetting resin composition used by this invention is used suitably for the use which requires precise granulation without position shift other than the liquid crystal dropping method of this invention.

[Example]

<Material>

Each material used in the Example and the comparative example is as follows.

Epoxy resin: Bisphenol-A epoxy resin, the Nippon Kayaku Co., Ltd. make, RE-310S, liquid phase (viscosity 13000-17000 mPa * s) at 25 degreeC, epoxy equivalent 175-190 g / eq.

Latent curing agents

EH4357 modified polyamine latent curing agent manufactured by Adeka Corporation;

EH4070S modified polyamine latent hardener manufactured by Adeka Corporation;

Ajicure PN-23 Ajinomoto Co., Ltd .;

Novacure HX-3722 manufactured by Asahi Kasei Epoxy Co., Ltd.

&Lt; Example 1 >

64.5 parts of epoxy resin RE-310S (manufactured by Nippon Kayaku Co., Ltd.) and 35.5 parts of latent curing agent EH-4357S (manufactured by Adeka Co., Ltd.) were stirred and mixed, and then dispersed in a ceramic triaxial roll mill to disperse the resin of Example 1. A composition was obtained.

<Example 2>

64.5 parts of epoxy resin RE-310S (manufactured by Nippon Kayaku Co., Ltd.) and 35.5 parts of latent curing agent EH-4070S (manufactured by Adeka Co., Ltd.) were stirred and mixed, and then dispersed in a ceramic triaxial roll mill to disperse the resin of Example 2. A composition was obtained.

Comparative Example 1

83.3 parts of epoxy resin RE-310S (manufactured by Nippon Kayaku Co., Ltd.) and 16.7 parts of the latent curing agent Azicure PN-23 (manufactured by Ajino Moto Fine Techno Co., Ltd.) were stirred and mixed, and then dispersed with a ceramic triaxial roll mill. The resin composition of Comparative Example 1 was obtained.

Comparative Example 2

76.9 parts of epoxy resin RE-310S (manufactured by Nippon Kayaku Co., Ltd.) and 23.1 parts of latent curing agent Novacure HX-3722 (manufactured by Asahi Kasei Epoxy Co., Ltd.) were stirred and mixed, and then dispersed in a ceramic triaxial roll mill. The resin composition of 2 was obtained.

<Measurement experiment of characteristic>

The characteristic of the resin composition of the said Example and the comparative example was measured as follows. The measurement results are shown in Table 1.

Availability time: Availability time is the time when the viscosity in the measurement period reached twice the initial viscosity.

Gelation time: Hot plate method By the measuring method of gel time, the composition sample of an Example and a comparative example was put on the 100 degreeC hotplate, and the time which a composition gelatinized was made into gelation time. As for gelation, as for the description in a main body, the state which became sticking a wooden stick in the composition during heating, and forming the thread of about 2-3 cm is made into gelation time.

Seal shape stability: After mixing and defoaming the spacer 1% with the obtained sealing agent, after filling it into the syringe, the rectangular frame was apply | coated on the glass substrate. Subsequently, an appropriate amount of liquid crystal is dropped into the rectangular boundary frame, and another glass substrate is loaded under vacuum. The vacuum is released and heat cured at 100 ° C for 1 hour. The sealing state after hardening is observed, and the same state as before hardening is judged as favorable, and when there exists a deformation | transformation, a crack, etc., it determines with being impossible.

The compositions of Examples 1 and 2 satisfy the characteristics of the thermosetting resin composition used in the present invention in terms of pot life, gelation time and sealing shape stability.

As is apparent from the above, various changes can be made without departing from the gist of the present invention. Therefore, the form described here is an example, The range of this invention described in the claim is not limited to this.

The LCD manufacturing method by the liquid crystal dropping method of this invention can manufacture LCD easily, without the need of a special ultraviolet irradiation apparatus, and maintaining the precise position alignment precision, without a position shift. And LCD, especially the sealing part is excellent in durability and reliability. Therefore, it is useful as an LCD manufacturing method.

Claims (7)

It is a method of manufacturing the liquid crystal display device which has a liquid crystal layer between a 1st board | substrate and a 2nd board | substrate by the liquid crystal dropping method,
(a) applying a thermosetting resin composition containing an epoxy resin and a latent curing agent and having a gelation time at 100 ° C. of 3 minutes or less to a sealing region surrounding the substrate surface at the periphery of the first substrate surface,
(b) dropping a liquid crystal onto a central region surrounded by the sealing region on the surface of the first substrate,
(c) superposing the second substrate on the first substrate, and
(d) Heating step of curing the thermosetting resin composition
Characterized by having a. The method according to claim 1, wherein the step of (c) overlapping is performed in a state in which the thermosetting resin composition has fluidity, and then, the heating step is performed in the (d) heating step. The method according to claim 1, wherein the heating step (d) is started before the overlapping step (c) is completed. The method according to any one of claims 1 to 3, wherein the thermosetting resin composition further contains an additive selected from the group consisting of fillers, thixotropic imparting agents and silane coupling agents. . The method according to any one of claims 1 to 4, wherein the epoxy resin contains an epoxy resin selected from the group consisting of bisphenol type epoxy resins, novolac type epoxy resins, and biphenyl type epoxy resins. . The method according to any one of claims 1 to 5, wherein the latent curing agent is selected from a modified amine latent curing agent. It contains an epoxy resin and a latent hardener, and gelation time in 100 degreeC shows 3 minutes or less, The thermosetting resin composition for liquid crystal dropping methods used by the method of Claim 1 characterized by the above-mentioned.