JPS6217729A - Production of cell for sealing liquid crystal - Google Patents

Abstract

PURPOSE:To improve the airtightness of a liquid crystal sealing cell and to improve the resistance to heat, cold and water by coating an adhesive agent consisting of a prescribed ratio each of a cationic polymer and photo initiator on base materials for a cell or materials to be adhered for the cell and subjecting these materials to compression seaming by way of backing then to curing the adhesive agent by UV rays. CONSTITUTION:>=1 kind of the cationic polymerizable compds. essentially consisting of an epoxy resin having an oxysilane ring in one molecule and 10-50pts.wt., by 100pts.wt., said polymerizable compds., compd. having >=2 hydroxyl groups in one molecule and having 50-5,000 number average mol.wt. are incorporated into the adhesive agent for sealing the liquid crystal. The initiator which can initiate the polymn. of the polymerizable compds. and liberates a Lewis acid catalyst when irradiated with UV rays is incorporated therein and such adhesive agent is used at 0.5-10pts. wt. by 100pts.wt. polymerizable compds. The adhesive agent constituted in such a manner is coated on the base materials or the materials to be adhered for the cell and the respective materials to be adhered or base materials are subjected to compression sealing by way of backing then the adhesive agent is cured by UV rays, by which the airtightness of the liquid crystal sealing cell is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel method for manufacturing a sealing cell.

[Conventional technology and problems]

In recent years, methods for storing electrical and electronic materials using sealing cells have become popular mainly in the electrical and electronic industries. In particular, liquid crystal encapsulation methods using glass or film as cells have been widely put into practical use. This cell for enclosing liquid crystal is a part having an important function, and is required to have extremely high physical properties. In other words, the materials that make up the cells must be strongly bonded to each other, must have high airtightness, and must have excellent chemical and physical stability against moisture, heat, etc. . Currently, in manufacturing cells for sealing, a method is generally used in which adhesives are used to bond cell materials, that is, cell base materials and cell adhesives.

Currently, adhesives used for this purpose are mainly based on epoxy resins; in the past, two-component epoxy resins were used, and currently, one-component epoxy resins are mainly used. When manufacturing cells using these adhesives,
A method is used in which the adhesive is screen printed on a cell base material, an adherend is applied, and the adhesive is pressed to about 10 to 30 kII/crI and cured by heating. However, in order to prevent the printed pattern from collapsing due to the flow of the adhesive when the adherend is applied, preliminary curing is performed for several hours to semi-cure before heating and curing, and after pressing, the main curing is performed for several hours. is common. However, the time required for curing them is very long, and the production efficiency is extremely low, which has been a problem.

In order to solve these problems, UV-curable adhesives that harden in a short time with UV rays were considered, but the chemical and physical stability of the manufactured liquid crystal cells against moisture, heat, etc. was poor, making them impractical. There was a lack of

[Means for solving problems]

As a result of intensive studies to solve these problems, the present inventor discovered that an adhesive using a cationically polymerizable compound is very suitable as an adhesive for liquid crystal sealing cells, and completed the present invention. did.

That is, the present invention provides: (a) one or more cationically polymerizable compounds whose main component is an epoxy resin having an oxirane ring in one molecule; (b) 10 to 50 parts by weight per 100 parts by weight of the cationically polymerizable compound. (3) A compound having two or more hydroxyl groups in one molecule and having a number average molecular weight of 50 to 3,000;
15 to 100 parts by weight of the cationic polymerizable compound
An adhesive consisting of a photoinitiator weighing 10% by weight and fillers, solvents, additives, etc. as necessary is applied onto the cell substrate or cell adherend, respectively. This is a method for producing a cell for liquid crystal sealing, which is characterized by applying and pressing a base material and then curing it with ultraviolet light, or further curing it with heat after curing it with ultraviolet light.

The cationically polymerizable compound as component (a) used in the present invention is one or more cationically polymerizable compounds whose main component is an epoxy resin having two or more oxirane rings in one molecule. is bisphenol A type epoxy resin, bisphenol yfJl epoxy resin,
Examples include novolac type epoxy resins and alicyclic epoxy resins. Examples of the darkening hisphenol A type epoxy resin include Epicote 82B and 'Epicote 834.
, Epicor-l-856, Epicort 1001, Epicort 1004 (manufactured by Shell Chemical Co., Ltd., trade names), DK
R-331, DKR-532, DER-661, DER
-664, DER-667 (manufactured by Dow Chemical Company,
(trade name), and these may be used alone or in combination. Bisphenol F type epoxy resins include Epicort 807 (manufactured by Shell Kagaku, trade name), Epiclon 830, and Epiclon 8308 (Dainippon Ink).
products, product names), etc. Examples of the novolac type epoxy resin include Epicort 152, Epicor 1-154, (trade names manufactured by Shell Chemical Co., Ltd.), Araldite FiPN11'5B, and Araldite EPN1.
139, Araldite ECN1235, Araldite E
Examples include CN1273, Araldite ECN1280, and Araldite ECN1299 (trade names, manufactured by Ciba Geigy), which may be used alone or in combination. Further, as the alicyclic epoxy resin, for example, Araldite CY175, Araldite CY177, Araldite CY179, Araldite CYI84, Araldite CY192 (trade name, manufactured by Ciba Geigy).
, ERL-4221, ERL-4299, gRL-4
254 (manufactured by Union Carbide, trade name), etc., and these may be used alone or in combination. Other polybutadiene-based epoxy resins can also be used, and mixtures with the various epoxy resins mentioned above can also be used. Further, a monofunctional epoxy diluent may be used in the cationic polymerizable compound within a range that does not impede the properties of the cured product.

Examples of the compound (0) used in the present invention having two or more hydroxyl groups in one molecule and having a number average molecular weight of 50 to 3,000 include ethylene glycol, propylene glycol, 1.4-butadiol, diethylene glycol, and dipropylene. Glycol, triethylene glycol, 1.5
-Low molecular polyhydric alcohols such as bentanediol, glycerin, trimethylolpropane, molecular t50-500
Polyfunctional polyols such as polyethylene glycol, polypropylene glycol, polycaprolactone polyol, and polyester polyol can be mentioned. These polyfunctional polyols may be used alone or in combination. When the number average molecular weight of the polyol is greater than 3000, the adhesive has poor curability and poor adhesion to the cell substrate.

The amount of the polyhydric alcohol and polyfunctional polyol added to component (A) is 10 to 50 parts by weight per 100 parts by weight of component (A).
4 parts by weight, more preferably 15 parts by weight or more.
It is 0 parts by weight or less. When the amount of component (B) added to component (A) is less than 10 parts by weight or more than 50 parts by weight, the adhesion of the cured adhesive to the cell base material is poor;
It cannot be used for liquid crystal sealing cells.

By irradiating the component (c) used in the present invention with ultraviolet rays, (
Examples of the photoinitiator that releases a Lewis acid catalyst capable of initiating polymerization of the cationic polymerizable compound of component (a) include aromatic diazonium salts, aromatic halonium salts, aromatic onium salts, and the like. Among these photoinitiators, aromatic hacnium salts and aromatic onium salts are particularly preferred from the viewpoint of photocurability.

The aromatic halonium salt has the general formula CI)(:(R
1), (Rz)bx): CMQ(1)i d-”
[:I] (In the formula, R is a monovalent aromatic organic group, R2 is a divalent aromatic organic group, X is a halogen atom such as I, Br, or CI, M is a metal, and Q is a halogen atom. represent

a is 0 or 2, b is 0 or 1, and (a+b)
is equal to 2 or the valence of There are compounds.

Examples of the compounds represented by the general formula (I) include the following.

Further, as aromatic onium salts, general formula (II)-(j-k
) ((R3) r (R4) g (Rs)hY) i
(MJ:l (n:)(In the formula, R3 is a monovalent aromatic organic group, R3 is a monovalent aliphatic organic group selected from the group consisting of an alkyl group, a cycloalkyl group, and a substituted alkyl group. A polyvalent organic group selected from aliphatic organic groups and aromatic organic groups, Y is S, Ss, T'e, or N, P, As.

Element selected from sb and Bi, M is a metal or metalloid,
Q represents a halogen atom. f is an integer from 0 to 4, g is 0
~2 integer, h is an integer from 0' to 2, and (f+g
+h) is equal to the valence of Y, and 1=(j-k) holds, parentheses k is an integer from 2 to 7 and equal to the valence of M, and j is k
(representing a larger integer of 8 or less).

Examples of the aromatic onium salt represented by the general formula (n) include the following.

The amount of component (c) to be added to component (a) is 15 to 10 parts by weight per 100 parts by weight of component (i),
Preferably it is 1 to 5 parts by weight. When the amount is less than 15 parts by weight, the ultraviolet curing speed tends to be slow and the curing time tends to be too long. Moreover, if it exceeds 10 parts by weight, it is expensive and the residual photoinitiator may have an adverse effect on the liquid crystal.

In the present invention, fillers, solvents, and additives may be used as necessary. Examples of fillers include inorganic fillers such as calcium carbonate, magnesium carbonate, talc powder, kaolin, and quartz powder, and organic fillers such as polyethylene powder and polyester powder. They are added and mixed within a range that does not interfere with the mixing.

Furthermore, examples of the solvent include aromatic solvents such as toluene, xylene, and ethylbenzene; halogenated hydrocarbons such as methylene chloride, ethylene chloride, and trichloroethane;
Alcohols such as isopropyl alcohol, butanol, and cyclohexanol; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone;
Examples include cellosolve solvents such as methyl cellosolve, methyl cellosolve acetate, and methyl carpitol.

Further, as additives, for example, a leveling agent, a thixotropic agent, a silane coupling agent, etc. can be added within a range that does not impede the effects of the present invention.

The cell base material and cell adhesive used in the present invention include:
Glass is the main material. Possibly polyester resin,
Organic materials such as polyimide resin and polysulfone resin are also used. Typically, these cell substrates or cell adhesives are surface-treated with transparent electrodes, alignment films, etc.

Next, to specifically explain a typical manufacturing method of the present invention, screen printing of a compound/adhesive consisting of the compounds (a), (0), and (c) above and fillers, solvents, and additives as necessary The thickness of the film on the cell substrate is 3.
Apply the film to a thickness of ~100μ, cover with cell adhesive, and use a light source such as a low-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, or carbon arc lamp while pressurizing with a collet or vacuum bottle. The adhesive is cured in a range where the amount of irradiation light reaching the adhesive is 500 to 3000 m, r/cffl. Next, the pressure is released, and if necessary, the material is heated and cured. The heat curing conditions are generally such that the material is cured in a hot air dryer at a temperature of 100° C. to 200° C. for 5 to 120 minutes.

The liquid crystal sealing cell manufactured in this manner has extremely high airtightness and is exceptionally excellent in heat resistance, cold resistance, water resistance, and the like.

〔Example〕

Next, the method of the present invention will be specifically explained using Examples, but the present invention is not limited to these Examples.

Example 1 Bisphenol A type epoxy resin with a number average molecular weight of about 380 (manufactured by Yuka Shell Epoxy ■, trade name: Meiko Pico) 82
8) 100 parts by weight, 30 parts by weight of trifunctional polyol P-505 (manufactured by Daicel Chemical Industries ■, trade name, polyester polyol with a number average molecular weight of 550), KBM-403 (manufactured by Shin-Etsu Silicone ■, trade name, silane coupling agent) ) and 3 parts by weight of Aerosil+200 (Japan Aerosil■
Mix 2 parts of (trade name) and knead uniformly with three rolls, then add 1 part of crushed glass fiber with a diameter of 7μ as a spacer.
parts by weight and 3 parts of triphenylsulfonium hexafluoroantisupernate were added and mixed to prepare an adhesive. The viscosity of this product measured by a B-type viscometer at 25°C is 180.
It was Poise.

Next, a liquid crystal display cell for a digital wristwatch was manufactured using this adhesive under the conditions shown below.

Cell substrate: A transparent electrode made of indium trioxide was deposited on the surface of a glass plate 10 mm wide, 20 m long, and 1 blade thick using a conventional method, and the surface was treated with a polyimide alignment film. Item 0 Adhesive for cells: Same as base material for cells.

Coating process: The above adhesive was coated onto the cell base material to a film thickness of 7 μm using a 300-mesh screen printing plate with a coating width of 0.8 inches and a coating length of 9 inches in width x 18 squares in height. .

Adhesion process: Cover the cell base material coated with adhesive with the cell adhesive, pressurize with a vaquium pin, and then use a 2.5kW high-pressure mercury lamp (manufactured by Mitsubishi Electric ■, product name H25-UVA) as a light source. 10100O/c for adhesive! The adhesive was cured by irradiation with ultraviolet rays under conditions where a moderate amount of energy was applied. Thereafter, after releasing the pressure, it was left in a drying oven at 150° C. for 20 minutes to perform post-curing.

Finishing step: Biphenyl liquid crystal was injected into the sealing cell obtained above according to the twisted nematic display method, and the injection hole was sealed using a commercially available two-component epoxy resin to produce a liquid crystal display cell.

The liquid crystal display cell manufactured in this way was heated to 120°C±2.
A high temperature and humidity resistance test was conducted by placing the sample in a pressure tester adjusted to a temperature of °C.

Thereafter, the liquid crystal display cell was taken out every 10 o'clock, polarizing plates were applied to both the front and back surfaces, and a DC voltage of 6 V was applied between the electrodes, and the presence or absence of disturbance in the display pattern was observed with the naked eye. Normally, it is considered that the display pattern should not be disturbed for more than 10 hours, and the display cell of this example performed well for up to 20 hours.

Example 2 50 parts by weight of bisphenol F type epoxy resin having a number average molecular weight of about 360 (trade name: Epiclon 830, manufactured by Dainippon Ink ■), Bakelite ERL-4221 (cycloaliphatic epoxy resin, U, C, C, trade name, manufactured by Dainippon Ink, Inc.) , number average molecular weight approximately 270
) 50 parts by weight, polyether polyol with number average molecular weight 400 (MN-400, trade name manufactured by Mitsui Nichia Urethane ■)
20 parts by weight, 2.5 parts by weight of KBM-403, talc (
Micro Ace L+-1.

Made by Nippon Talc (trade name) 30 parts by weight, and Erosil +2
Mix 2.5 parts by weight of 0.00, mix evenly with three rolls, and then add 1 part by weight of crushed glass fiber with a diameter of 7 μm and 2.5 parts of diphenyliodonium hexafluoroantimonate. An adhesive was prepared by mixing. The viscosity of this product measured by a B-type viscometer at 25°C is 25
There was 0 voice.

Next, a liquid crystal display cell was manufactured using this adhesive under the conditions shown below.

Cell base material: Same as Example 1.

Adherent material for cells: Same as base material for cells.

Coating process: Same as Example 1.

Adhesion process: Same as Example 1. However, this time it is 150'C20
No post-curing was performed for minutes.

Finishing process: Same as Example 1.

A durability test was conducted in the same manner as in Example 1, and the result was good for 10 hours or more.

Claims (1)

Scope of Claims: (a) one or more cationic polymerizable compounds whose main component is an epoxy resin having an oxirane ring in one molecule; (b) 10 to 50 parts by weight based on 100 parts by weight of the cationic polymerizable compound. a compound having a number average molecular weight of 50 to 3,000 and having two or more hydroxyl groups in one molecule of the weight part; (c) capable of liberating a Lewis acid catalyst capable of initiating polymerization of the cationically polymerizable compound upon irradiation with ultraviolet rays;
15 to 100 parts by weight of the cationic polymerizable compound
An adhesive consisting of 10 parts by weight of a photoinitiator is applied onto the cell base material or the cell adherend material, and the cell adherend material or cell base material is applied and pressed, respectively, and then cured by ultraviolet rays. A method for manufacturing a cell for liquid crystal sealing, characterized by: