JPS62133425A - Composition of sealing material for liquid crystal cell - Google Patents

Abstract

PURPOSE:To satisfy completely several conditions required for screen-printing a sealing material on a substrate surface, and for heat-curing after lamination by constituting a compsn. of the sealing material for a liquid crystal cell of liquid epoxy resin contg. phosphoric ester groups in the skeletal structure of the epoxy resin, usual liquid epoxy resin, a polythiol compd., a curing accelerator, and an inorg. filler. CONSTITUTION:The compsn. consists of a liquid epoxy resin, liquid epoxy compd. contg. phosphoric ester, a polythiol compd., a curing accelerator, and an inorg. filler. The epoxy resin in the sealing material compsn. is necessary to be a mixture of a liquid epoxy resin contg. phosphoric ester group in combination with a liquid epoxy resin. The phosphoric ester group contained in the epoxy resin contributes to increase adhesive strength of the sealing material to an ITO electrode, so the stability of the adhesive property of the sealing layer is improved remarkably. Any polythiol compd. contg. >=2 -SH groups having sufficient compatibility to epoxy resin may be useful. When this compd. is used for a curing agent, satisfactory light resistance is realized due to the oxidation preventing effect of the -SH group. Furthermore, low temp. curing property, and flexibility are improved characteristically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sealant composition used in the production of liquid crystal cells used in display bodies, and more specifically, the present invention relates to a sealant composition that is used in the production of liquid crystal cells used in display bodies, and more specifically, the composition is composed of a liquid synthetic resin, The present invention relates to a sealant composition comprising a phosphoric acid ester-containing enoxy liquid, a hiritiol compound, a curing accelerator, and an inorganic filler.

[Prior art] A conventional liquid crystal cell has a cavity (cavity thickness 5 to
10 μm) was left in the liquid crystal injection hole and sealed.
It is generally obtained by enclosing the liquid crystal in the cavity, and then sealing the enclosing port with an ultraviolet curing resin, with an alignment film attached (a glass or plastic film is used as the polar substrate).

On the other hand, in recent years, there has been a strong desire to make liquid crystal cells thinner due to the trend of increasing viewing angles due to lighter and thinner liquid crystal displays and larger sizes, and there is a trend toward reducing the thickness of glass substrates or adopting plastic film substrates. is sudden.

Under these circumstances, the requirements regarding the sealing layer have changed in appearance, and there is a strong desire to respond to these requirements.

That is, specifically, the following has been required.

As liquid crystal cells become larger, it is necessary to form a substrate and a layer in which the ratio of the area of the seal layer to the cell area is extremely small.

2. Due to the reduction in substrate thickness and the adoption of plastic film substrates, it is necessary to provide the sealing layer with appropriate flexibility due to changes in the manufacturing process and the environment in which the liquid crystal cell is used.

3. From the viewpoint of mass production and workability, there is a need for a sealant that has a long shelf life and can be cured quickly at low temperatures.

4. Since the liquid crystal is sealed after the cavity is formed, it is essential that the sealant be inactive with respect to the liquid crystal.

5. Rounding sealants, which are mainly used for transmissive liquid crystal displays, are required to have high light resistance and heat resistance to withstand backlight.

6. In order to effectively utilize the area of the liquid crystal cell, the seal layer must have a narrow line width, and the seal layer must have sharp linearity.

These severe requirements could not be met with the conventionally used sealants based on polyamides and polyamides.

[Purpose of the invention]

The inventors of the present application conducted extensive research in an effort to obtain a sealant that could satisfy these # and required temperature requirements, and after discovering the superiority of a polythiol-epoxy resin composition, filed an application. However, since the 170g surface is a hydrophilic surface, there are some difficulties in terms of adhesion with normal epixy systems, so we conducted intensive studies to improve this point, and found that the combination of nixy resin containing phosphate ester groups was an excellent improvement. We have found that this is effective and have arrived at the present invention.

Structure of the Invention] The epoxy resin 111 in the sealant composition according to the present invention must be a combination of a liquid epoxy resin and a liquid epoxy resin containing a phosphoric acid ester.

In other words, the phosphoric acid ester group contained in the edoxy side fat contributes to strong adhesion with the ITO electrode, making it a seal! - The adhesion stability is significantly improved. On the other hand, using only a phosphoric acid group-containing epoxy resin has the disadvantage of increased viscosity and poor printability.

In addition, in the present invention, any compound containing two or more 15H groups that has good compatibility with the engeki resin can be used as the talythiol compound, and if the compound is present all around the compound as a curing agent, the -SH group can be oxidized. Good light resistance can be obtained due to the prevention ability, and characteristics such as low-temperature curability and flexibility are also exhibited. Specifically, the following compounds are used alone or in combination, and the general formula is 1 mole of 18H group to 1 mol of x4xy group. That is, 2,2'- Dimethyl mercapto diethyl ether, intererythritol β-thioglycolate, glycerin β
-thioglucorate, sorbitol β-thioglycolate, trishydroxyethyl (βthiogelcol) isocyanurate, trishydroxyethyl (mercaptopropyl)in cyanurate, and the like.

Next, as the curing accelerator M used in the present invention, all accelerators used in curing acid anhydride-based Nixy resin can be used, but in particular, imidazole-based compounds such as 2-ethyl-4-methylimidazole (hereinafter referred to as 2E4klZ>2.4 , 6) Amine compounds such as (dimethylamine methyl) phenol (hereinafter referred to as 'rAP) are preferred.

In addition, salts of the above compounds are preferred as latent accelerators, especially 2E4M, in order to improve the hardness and curing speed after mixing the two liquids (KJ-Kishi side fat and streamtail).
Salts of Z and triphenylphosphite and TAP and salts of compounds having an ethylenic 2ffi bond with a carboxyl group are preferred.

These accelerated AQs are stable at ambient temperatures, and therefore rapidly dissociate at temperatures of 80° C. or higher, exhibiting rapid curing properties, despite the presence of stable Ittra 7.

Further, from the viewpoint of printability and prevention of bleeding during printing, the addition of an inorganic filler is essential, and the addition of titanium white is particularly preferable from the standpoint that linearity during printing can be checked. Further, since titanium white has ultraviolet light absorbing properties, it is preferable from the viewpoint that it exhibits extreme light resistance to backlight light when producing gold for transmission type liquid crystal devices, etc.

〔Effect of the invention〕

The resulting blended composition is an excellent composition that can form an excellent cured sealing layer that completely satisfies the above-mentioned requirements when it is screen printed on the substrate surface and then heat-cured after lamination.

Examples are shown below.

Example 1 Cyindium was deposited on a non-optically active polyether sulfono film obtained by a melt extrusion method by the Snow Z-vine method.
A tin oxide thin film was formed (sheet resistance: 380 Ω/unit). Next, a circuit consisting of electrodes and edge parts was formed using the thin film using a normal etching method. After that, an alignment film treatment was performed on the circuit surface using an imide resin. I did it.

Next, a mixture of the main ingredient and curing agent having the following composition, which had been kneaded with an ink roll on the Iul road board upper plate, was printed by screen printing, leaving the liquid crystal injection port. During printing, the printing speed was 0.5 ttrtn, and the printing thickness was 20 μm.

Base component composition Hardener composition Main component/curing agent blend ratio = 100/95 Next, the upper circuit board (PES/ITO circuit board) was pressed together with a gap agent of 10 μm interposed therebetween and heat-cured for 120'C2hrs.

The seal width of the cured product is 1 inch, and the thickness between the stains is 6 to 7 μm.
Met.

Next, liquid crystal was injected into the cavity of the pasted product from the injection port under vacuum, and the injection port was sealed with UV curing resin. The obtained liquid crystal cell was strongly and completely sealed, had flexibility, and was useful as a display body with excellent moisture and heat resistance reliability.

Claims (3)

[Claims] (1) Manufacturing a liquid crystal cell by sealing the four peripheries of two substrates with alignment films equipped with opposing indium-tin oxide thin film electrodes to form a certain cavity, and enclosing the liquid crystal cell within the cavity. It is a sealing agent used in Features of sealant for liquid crystal cells (2) The sealant composition for a liquid crystal cell according to claim 1, wherein the curing accelerator is a combination of 2-ethyl-4-methylimidazole and triphenylphosphite. (3) A patent claim in which the curing accelerator is a salt of 2,4,6 tri(dimethylaminomethyl)phenol and a compound having an ethylenic double bond and a -COOH group in the molecule. Sealant composition for liquid crystal cells according to scope 1