JPH0915611A - Sealing material composition for assembling liquid crystal cell - Google Patents

Abstract

PURPOSE: To provide a sealing material compsn. for film liquid crystal cells which has pliability to follow up the flexibility of films and has excellent moisture resistance. CONSTITUTION: This sealing material compsn. for assembling the liquid crystal cells consisting of an epoxy resin, an epoxy resin hardener and other components contains (a) 10 to 50 pts.wt. polyethylene glycol diglycidyl ether which is liquid at room temp. and (b) 90 to 50 pts.wt. bisphenol type epoxy resin which is liquid at room temp. at an epoxy resin component, (c) 20 to 80 pts.wt. a trifunctional thiol compd. which is liquid at room temp. as an epoxy resin hardener, (d) 0.5 to 5.0 pts.wt. silane coupling agent, (e) 1 to 10 pts.wt. amorphous silica having an average grain size of <=1μm and (f) 5 to 50 pts.wt. inorg. packing material exclusive of the amorphous silica as essential components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sealing material composition for assembling a liquid crystal cell.

[0002]

2. Description of the Related Art Conventionally, most liquid crystal cells use glass as a substrate, but in recent years, film liquid crystals having an engineering plastic as a substrate have been developed. Advantages of the film liquid crystal are that it is thinner, does not break, is lighter than glass liquid crystal, and can be used for curved surface display. The property required for the film liquid crystal cell sealant is that it does not adversely affect the liquid crystal molecules because it is in direct contact with the liquid crystal molecules, but it must be a soft material that follows the flexibility of the film. Also, it has excellent moisture resistance in terms of durability of the liquid crystal display element, strong adhesiveness that can withstand expansion and contraction due to temperature change of the liquid crystal cell, and various external stresses, and constant liquid crystal cell gap. There is no filler having a diameter larger than the diameter of the spacer in order to hold it.

As described above, many characteristics are required for the sealing material, but unlike the sealing material for glass liquid crystal cells, which may exhibit rigid physical properties when it becomes a cured material, especially the cured material of the sealing material is flexible. There are very few sealing materials for film liquid crystals, which have an essential property, and have excellent moisture resistance to external humidity. Incidentally, Japanese Patent Publication No. 6-90379 mentions a sealant for a plastic film which is characterized by containing epoxidized polyether glycol as a main component, but an epoxy resin having an aliphatic main chain is aromatic. It has a drawback that it is inferior in curing reactivity as compared with a glycidyl compound having both ends on its main chain.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a film-liquid crystal cell sealing material composition having flexibility that follows the flexibility of a film and excellent moisture resistance.

[0005]

The inventor of the present invention has made extensive studies to solve the above-mentioned problems, and as a result, has completed the present invention. That is, the present invention relates to a sealant composition for assembling a liquid crystal cell, which comprises an epoxy resin, an epoxy resin curing agent and other components, wherein (a) polyethylene glycol diglycidyl ether (hereinafter referred to as liquid) at room temperature is used as the epoxy resin component. Abbreviated as PEG epoxy) 10
50 parts by weight, (b) 90 to 50 parts by weight of a bisphenol type epoxy resin (hereinafter abbreviated as bis type epoxy) which is liquid at room temperature, and (c) 20 to 30 parts of a trifunctional thiol compound which is liquid at room temperature as an epoxy resin curing agent. 80 parts by weight, and as another component, 0.5 to (d) a silane coupling agent.
5.0 parts by weight, (e) 1 to 10 parts by weight of amorphous silica having an average particle size of 1 μm or less, (f) 5 to 50 parts by weight of inorganic filler other than amorphous silica having an average particle size of 2 μm or less A sealant composition for assembling a liquid crystal cell, which comprises a part as an essential component.

The epoxy resin used in the present invention comprises a PEG epoxy which is liquid at room temperature and a bis type epoxy which is liquid at room temperature. The PEG epoxy used in the present invention is represented by the general formula (1).

[0007]

Embedded image (In the formula, n is an integer of 1 ≦ n ≦ 10)

PEG epoxies within this range are liquid. The amount of PEG epoxy used is from 10 to 50 parts by weight, preferably from 10 to 30 parts by weight, more preferably from 10 to 20 parts by weight, based on 100 parts by weight of the total epoxy resin component. In addition, the cured material of the sealing material becomes hard and rigid, and the followability to the deformation of the film is deteriorated, which is not preferable. On the other hand, if the amount used is more than 50 parts by weight, the curing reaction will be significantly delayed, which is not preferable. It is not possible to obtain a sealing material composition that combines suitable reactivity and flexibility suitable for practical use and is also excellent in moisture resistance for the first time by combining PEG epoxy with a bis type epoxy resin that is liquid at room temperature. It is particularly useful as a sealing material for film liquid crystal.

The room temperature liquid trifunctional thiol curing agent used in the present invention has, for example, a structure represented by the general formula (2).

[0010]

Embedded image (In the formula, R: an ester group or a carbonyl group)

Next, examples of the silane coupling agent used in the present invention include, for example, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-aminoethylaminopropylmethyldimethoxysilane, γ- Examples thereof include mercaptopropyltrimethoxysilane, and the amount thereof is 0.5 to 5 parts by weight with respect to 100 parts by weight of the epoxy resin. By adding these silane coupling agents, the adhesiveness to the film substrate can be remarkably improved, and the entry of external moisture into the liquid crystal cell can be inhibited.

Next, examples of the inorganic filler used in the present invention include titanium oxide, spherical silica, alumina, calcium carbonate, amorphous silica and the like, which are essential conditions for keeping the cell gap of the liquid crystal uniform. The maximum particle size is smaller than that of the spacer. Titanium oxide, spherical silica, alumina, calcium carbonate, etc. having an average particle size of 2 μm or less and amorphous silica having an average particle size of 1 μm or less are used. Amorphous silica having an average particle size of 1 μm or less is used to impart thixotropy to the entire system. If a certain thixotropic property is not imparted, the screen printability is adversely affected and a precise seal pattern cannot be formed. It should be noted that it is desirable to use these inorganic fillers that have been conditioned for at least 3 months in an atmosphere having a temperature of 60 to 70 ° C. and a humidity of 2 to 5%. If this pretreatment is not carried out, the water content in the sealant composition will change seasonally. Sealing materials made using the above inorganic fillers that have not been subjected to humidity control have seasonal fluctuations in viscosity and thixotropy, disturbing the linearity of the seal pattern during prebaking on the line, and preventing bleeding etc. It may cause it. Further, there may be various adverse effects such as causing a foaming phenomenon of the sealing material when the films are overlapped and main cured.

The amount of the amorphous silica used is the epoxy resin 1
It is 1 to 10 parts by weight with respect to 00 parts by weight, but when it is less than 1 part by weight, thixotropy is deteriorated, and a seal pattern formed by screen printing or a dispenser has a shape when passing through a heat process. May cause disturbances in. On the other hand, if the amount of use is more than 10 parts by weight, the fluidity of the entire sealing material system is deteriorated, which adversely affects plate separation during screen printing, which is not preferable.

Further, the amount of the inorganic filler other than the amorphous silica used is 5 to 50 parts by weight with respect to 100 parts by weight of the epoxy resin, but when it is less than 5 parts by weight, the viscosity of the entire sealing material is remarkably lowered. However, the fluidity is extremely increased at the time of heat such as pre-baking, so that the shape is disturbed, which is not preferable. Further, when more than 50 parts by weight is used, the viscosity is remarkably increased, the workability at the time of forming the seal pattern such as screen printing is adversely affected, and the elastic modulus of the cured material of the seal material is increased. It is not preferable because the property is not obtained.

The sealant composition for assembling the film liquid crystal cell of the present invention is usually cured using a curing accelerator. The type and amount of the curing accelerator that can be used are not particularly limited, and examples thereof include trisdimethylaminomethylphenol (TAP), salts of TAP and octylic acid, imidazoles, triphenylphosphine (TPP), and the like. . The amount used is 0.1 with respect to 100 parts by weight of the epoxy resin.
-8 parts by weight, preferably 0.1-3 parts by weight. When the amount used is less than 0.1 part by weight, the effect promoting action cannot be sufficiently exhibited, which is not preferable. On the other hand, when the amount is more than 8 parts by weight, the pot life is shortened and the workability is adversely affected, which is not preferable.

[0016]

The present invention will be described in more detail with reference to the following examples. Example 1 A PEG epoxy represented by the formula (1) (n =
9, Epolite 400E, manufactured by Kyoeisha Chemical Co., Ltd., epoxy equivalent 300) 20 g, bisphenol A type epoxy (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 190) 80 g was stirred with a DC motor and the average particle size was 0. 5 g of 0.5 μm amorphous silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) was uniformly dispersed. Furthermore γ
-Glycidoxypropyltrimethoxysilane (Sila Ace S-510, manufactured by Chisso Corporation) 1 g, average particle size 1 μm
The following titanium oxide (CR-EL, Ishihara Sangyo Co., Ltd.) 80
After adding g, the mixture was uniformly mixed and further kneaded with a three-roll mill to obtain a main agent. In addition, a trifunctional thiol having a isocyanurate skeleton represented by the formula (2) (THEIC-BMP
A, Yodo Chemical Co., Ltd., mercapto equivalent 174) 85 g,
Octyl acid salt of trisdimethylaminomethylphenol (K-61B, manufactured by Anchor Chemical Co., Ltd.) 1.0 g, amorphous silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) having an average particle size of 0.5 μm, 5 g, average 20 g of titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) having a particle size of 1 μm was added and uniformly mixed with a DC motor, and further kneaded with a three-roll to obtain a curing agent. 100/60 of these main agents / hardeners
The mixture was mixed in the following ratio and well stirred to obtain a sealing material for liquid crystal cell assembly. In the above main agent, a new main agent was prepared with a formulation in which all PEG epoxy was replaced with bis A epoxy, and mixed with a curing agent at an equivalent ratio of 1 and cured. When the durometer hardness of each cured product was measured, the one using PEG epoxy was Shore D10, but the one replacing all with bis A epoxy was Shore D60.

Example 2 20 g of PEG epoxy (n = 4, Epolite 200E, Kyoeisha Chemical Co., Ltd., epoxy equivalent 200) was added to bisphenol F type epoxy (E).
XA835LV, manufactured by Dainippon Ink Co., Ltd., epoxy equivalent 1
65) 50 g and bisphenol A type epoxy (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 190) 30 g were added, and the mixture was stirred by a DC motor and amorphous silica having an average particle size of 0.5 μm (R-972, Nippon Aerosil). 5 g (manufactured by K.K.) was dispersed uniformly. Further γ-
Aminopropyltriethoxysilane (S-330, manufactured by Chisso Corporation) 1 g, titanium oxide (C having an average particle diameter of 1 μm or less)
R-EL, manufactured by Ishihara Sangyo Co., Ltd.) (80 g) was added and uniformly mixed, and further kneaded with a three-roll mill to obtain a main agent.
Further, a trifunctional thiol having a isocyanurate skeleton represented by the formula (2) (THEIC-BMPA, manufactured by Yodo Chemical Co., Ltd.,
To 98 g of mercapto equivalent 174), trisdimethylaminomethylphenol (TAP, manufactured by Kayaku Akzo Co., Ltd.) was added.
5 g, amorphous silica having an average particle size of 0.5 μm (R-97
2, Nippon Aerosil Co., Ltd.) 5 g, and titanium oxide (CR-EL, Ishihara Sangyo Co., Ltd.) 15 g with an average particle size of 1 μm were added and uniformly mixed with a DC motor. To obtain a curing agent. 10 of these base / hardening agents
The mixture was mixed at a ratio of 0/64 and stirred well to obtain a sealing material for liquid crystal cell assembly. All of the PEG epoxy components in this composition were replaced with bis type epoxy to prepare a cured product. Next, each cured product was subjected to a high temperature and high humidity treatment at 85 ° C./85%/24 hr, and the water absorption rates of both were compared, and both were 2%. Also, when the durometer hardness of each cured product was measured, the one using PEG epoxy was Shore A40, but the one replacing all with bis A epoxy was Shore D3.
It was 0.

[0018]

EFFECTS OF THE INVENTION A cured sealant material has both flexibility and moisture resistance, and a sealant composition useful for a film liquid crystal cell can be obtained.

Claims (3)

[Claims] 1. A sealant composition for assembling a liquid crystal cell, comprising an epoxy resin, an epoxy resin curing agent and other components, wherein (a) polyethylene glycol diglycidyl ether which is liquid at room temperature is used as the epoxy resin component.
˜50 parts by weight, (b) 90 to 50 parts by weight of a bisphenol type epoxy resin which is liquid at room temperature, and 20 to 30 parts of a trifunctional thiol compound which is liquid at room temperature (c) as an epoxy resin curing agent.
80 parts by weight, 0.5 to 5.0 parts by weight of (d) a silane coupling agent, (e) 1 to 10 parts by weight of amorphous silica having an average particle size of 1 μm or less, (f) ) A sealant composition for assembling a liquid crystal cell, which contains 5 to 50 parts by weight of an inorganic filler other than amorphous silica having an average particle diameter of 2 µm or less as an essential component. 2. The sealant composition for assembling a liquid crystal cell according to claim 1, wherein polyethylene glycol diglycidyl ether is represented by the general formula (1). Embedded image (In the formula, n is an integer of 1 ≦ n ≦ 10) 3. The sealant composition for assembling a liquid crystal cell according to claim 1, wherein the trifunctional thiol compound is represented by the general formula (2). Embedded image (In the formula, R: an ester group or a carbonyl group)