JPS59137929A - Sealing material for liquid crystal display panel - Google Patents

Abstract

PURPOSE:To obtain a sealing material which is short in curing time and has an excellent characteristic by consisting essentially said material of epoxy polyacrylate, mixing bisphenol A diacrylate therewith, and adding a silane coupling agent and a photopolymn. initiator to the same. CONSTITUTION:Bisphenol A having about 400mol.wt. and acrylate of bisphenol F diglycidyl ether are used as an essential component of a sealing material, and bisphenol A diacrylate is mixed therewith in order to decrease the viscosity and to provide the strength of a cured material. A silane coupling agent having an acryl group in its molecule is used as the silane coupling agent to be added to said material in order to provide adhesiveness. A benzoin ether compd. is used at about 1.5wt% by weight of the resin as a photopolymn. initiator. The sealing material is curable by UV light, has a short curing time, is suitable for printing for its low viscosity and provided substantial adhesive strength.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sealing material for bonding a liquid crystal display panel container constructed by bonding a pair of glass substrates.

Conventional structure and its problems The container of the liquid crystal display panel has a transparent electrode and an alignment film on all stages.
It is manufactured by placing a pair of glass substrates facing each other and sealing both substrates with a sealing material. This sealing material prevents the liquid crystal from being damaged by moisture and other impurities that enter from the outside, and also serves to create a gap in the liquid crystal display panel by containing nupesa such as glass fiber. Conventionally, liquid organic resins are often used as K. □ In particular, thermosetting epoxy resins using acid anhydrides or amine compounds as curing agents exhibit excellent properties as sealing materials and have been widely used. The above-mentioned resin requires full heating during curing, and curing usually takes about 2 to 4 hours, and special consideration is required to provide a gap in the liquid crystal display panel during curing. In other words, in order to create a gap equal to the diameter of the Nupesa mixed in the resin, two sheets were bonded together facing each other at the same time as they were heated.
Uniform pressure must be applied to each substrate. This is J
- Metal surface plates with high precision flatness are usually used, but due to this heat capacity, there are problems in that extra time is required for heating and cooling, and workability is very poor. .

As described above, conventional epoxy sealing materials require a long time for curing process and are complicated.
The disadvantage is that it has a large impact on the productivity of liquid crystal display panels.

Purpose of the Invention The present invention c. In order to reduce the time required for panel assembly and resin curing processes in the production process of liquid crystal display panels and increase productivity, an epoxy system with short curing time and excellent properties is used. The overall objective is to provide a sealing material that can replace resins.

Construction of the Invention One possible short cure time resin is a series of resins that can be cured by ultraviolet light. This UV-curable resin has been extensively researched and developed due to its advantages of time-saving, energy-saving, and clean curing. Its uses are expanding.

It is clear that the productivity of LCD panels can be improved by using ultraviolet curable resins with these advantages as sealing materials for LCD panels, but in terms of the performance of the cured products, conventional Nothing comparable to curable epoxy resins has yet been found.

The present invention focuses on the fact that the photopolymerization of epoxy acrylate is chemically stable, and uses this as the main component, and bisphenol A diacrylate is added to reduce the viscosity and give strength. After mixing, a silane coupling agent and a photopolymerization initiator are added to impart adhesiveness.

That is, acrylates of bisphenol A and bisphenol F diglycidyl ether with a molecular weight of around 400 are:
Since it exhibits a very high viscosity at room temperature, 1-bisphenol A cyaze acrylate is mixed in to lower the viscosity and impart strength to the cured product. The silane coupling agent added to the silane coupling agent to impart adhesiveness is preferably one having an acrylic group in its molecule, and in order to react with the silane coupling agent on the surface of the glass substrate, K is added before curing with ultraviolet IIJK. to 8
Although heat treatment for about 15 minutes at 0''t is required, the sealing material does not harden due to this heat treatment, and therefore the above-mentioned gap opening operation step can be performed during ultraviolet irradiation.

As the photopolymerization initiator, benzoin ether compounds are suitable because they do not generate gas. If the concentration is about 1.5% by weight based on the resin, the curing time will be
It is suitable from the viewpoint of pot life, etc. 90 seconds is sufficient for curing with this ultraviolet ray.

Since the sealing material is usually applied onto the substrate by Nuclean printing, the printing properties are important. For this reason, it is effective to add a K layer stacking agent, but in the present invention, Merck T is mainly used for this purpose. It has been found that this Merck powder is compatible with the above-mentioned resin, imparts suitable sharpness to printing, and has a great influence on the strength and adhesiveness of the cured product.

Description of examples Next, embodiments of the present invention and their effects will be described.

Example 1゜ Epoxy acrylate (trade name, Viscoat Kou 5uO) was used as a sealing material.
1 Osaka Organic Chemical Co., Ltd.) 51 Bisphenol A diacrylate C brand name, Viscoat-+ 700. Osaka Organic Chemistry System) 51 Benzoin Ethyl Ether 0.15 F Silane Coupling Agent C Trade Name, KBM503. Made by Shin-Etsu Silicone)
O,l F Merck powder (product name,
Micronice 1 made by Nippon Talc)
A liquid crystal display panel container was assembled by applying and adhering this sealing material (21) to a pair of glass plates (c unit m) having a composition of uW and having dimensions as shown in Fig. 1 (c unit m). When a knife was inserted from one end (3) and a heating test was performed, it showed a strength of 1.6 to 1.8 and 9, and all specimens were broken in bulk. No resin flow was observed, and the seal had good linearity.

Example 2: Diazilyte of bisphenol F diglycidyl ether was used as a sealing material.
rate
5y Bisphenol A diacrylate 5y Pentwin isoprobyl ether o, 15p Silane coupling agent 0.1 Tatalk powder
When the same container as in Example 1 was made using the same composition as in Example 1 and a macroscopic peel test was conducted, it showed an odor intensity of 2.1 to 2.8, and other characteristics were the same as in Example 1. It was the same.

Example ).

Diazilyte of bisphenol A diglycidyl ether is used as a sealing material.
Shi - To
2.5 Diazylyte of bisphenol F diglycidyl ether
2.
5y Benzine ethyl ether 0.15y
Using a silane coupling agent with a composition of 0.1P Merck powder 4, the same container as in Example 1 was made, and all the same exfoliation tests were conducted, showing a strength of 1.7 to 2 stone odor. . Other characteristics were also similar to those in Example 1.

For comparison with conventional examples, the sealing material used was a thermosetting epoxy resin conventionally used, with a silane coupling agent (trade name, KBMl103, manufactured by Shin-Etsu Silicone) and a filler added. When containers similar to those in Examples 1 to 3 were made using an amine curing agent and subjected to a peel test, they exhibited a total strength of 1.1 to 1.9 Kp. In this product, some seal flow was observed during the heat treatment process.

As described above, the sealing material of the present invention is UV-curable, has a short curing time, has a low viscosity and is suitable for printing, and has sufficient adhesive strength as shown in the comparison with the conventional example described above. As a result, it has excellent performance as a sealing material for liquid crystal display panels.

[Brief explanation of the drawing]

FIG. 1 shows the structure and dimensions of a test piece subjected to a peel test according to an example of the present invention, with (a) being a plan view and (b) being a side sectional view thereof. (1)...Glass substrate, (2)...Sealing material, (
3) --- Naifetsuji insertion part. Name of agent: Patent attorney Etsuji Yoshizaki l1II! l (0) (b)

Claims (1)

[Claims] 1. Epoxy acrylate resin and bisphenol A
A sealing material for liquid crystal display panels that is cured by ultraviolet light and is made by adding a coupling agent to diacrylate and benzoin ether compounds. 2. The liquid crystal according to claim 1, wherein the epoxy acrylate resin is composed of either or both of bisphenol A diglycidyl ether diacrylate and bisphenol F diglycidyl ether diacrylate. Seal material for display panels. ), the sealing material for a liquid crystal display panel according to claim 1, wherein the coupling agent is a silane coupling agent having an acrylic group.