JPH0987363A - Photocurable composition, sealing material, method for sealing, and sealed liquid crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photocurable composition excellent in thixotropy, etc., by mixing an alicyclic epoxy compound with an aliphatic glycidyl ether type epoxy compound, hydrophobic silica particles and a cationic photopolymerization initiator. SOLUTION: This photocurable composition is prepared by uniformly mixing under agitation 60-90wt.% alicyclic epoxy compound (A) (e.g. a compound of formula I, II or III) in which an epoxy group is bonded to a 4-35C alicyclic structure and which has a molecular weight of 110-1,500, 5-40wt.% aliphatic glycidyl ether type epoxy compound (B) which is derived by bonding a glycidyl ether group to the terminal of an aliphatic compound and having a molecular weight of 110-1,500, 2-8wt.% hydrophobic silica particles the surface silanol groups of which are converted into hydrophobic groups, to an extent of 62-99.8wt.% and has a mean particle diameter of 3-100nm or below when measured in the form of primary particles, and 1-7wt.% cationic photopolymerization initiator which liberates a Lewis acid catalyst when irradiated with an actinic radiation such as ultraviolet rays, α rays, β rays or γ rays and optionally a coupling agent, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photocurable composition, and more particularly to a photocurable composition suitable for encapsulating a liquid crystal between two liquid crystal substrates of a liquid crystal display.

[0002]

2. Description of the Related Art A liquid crystal display basically has a structure in which liquid crystal is sealed between two liquid crystal substrates and transparent electrodes are laminated on the liquid crystal substrates. Conventionally, as a sealing material for sealing liquid crystal, polyimide, silicone resin, rubber, epoxy thermosetting resin (Japanese Patent Laid-Open No. 55-50).
No. 223) was used.

Of these, epoxy thermosetting resins are widely used because of their excellent adhesive strength with a liquid crystal substrate, heat resistance, and moisture resistance. However, in the process of bonding, pressurizing, heating and curing, there is a problem that the epoxy thermosetting composition to be cured flows and the position of the substrate is displaced, and the shape of the seal pattern is distorted. Further, it takes a time required for curing, and there is a problem in terms of production efficiency.

In order to solve these problems, it has been proposed to cure an epoxy photocurable composition which can be cured in a short time and use it as a sealing material (Japanese Patent Laid-Open No. 1-243).
No. 029 publication). However, there is a problem in that the adhesive strength, heat resistance, and moisture resistance are reduced as compared with the case where the epoxy thermosetting composition is cured and used as a sealing material.

Further, in the step of applying these compositions on a substrate with a predetermined thickness and width, thixotropy, which is easy to apply, and easy to maintain the applied shape until subsequent curing, has a thixotropic property. Desired. In conventional sealing materials, a filler is often added in order to impart thixotropy and enhance adhesion strength, heat resistance and moisture resistance (JP-A-55-50223, JP-A-2-114233, etc.). ). However, if the amount of the filler added is small, the application is easy, but it is difficult to maintain the shape after application, and if the amount is large, the shape is easy to maintain but the viscosity is high and the application is difficult. Even when it is considered that good thixotropy is imparted, it is difficult to apply the solution uniformly in a predetermined width and thickness, and it takes time, which causes a problem in production efficiency.

[0006]

The object of the present invention is to provide excellent thixotropy, uniform application in a short time, curing treatment at a low temperature in a short time, adhesive strength after curing, heat resistance, moisture resistance, etc. There is a development of a photocurable composition having excellent properties.

[0007]

As a result of earnest efforts, the present inventors have found that a specific epoxy compound component, a specific filler,
It has been found that the above object can be achieved by adding a specific photopolymerization initiator, and the present invention has been completed. Thus, according to the present invention, a photocurable composition comprising an alicyclic epoxy compound, an aliphatic glycidyl ether type epoxy compound, hydrophobic silica particles, and a cationic type photopolymerization initiator, a sealing material comprising the composition, The sealing material is applied onto at least one of the two liquid crystal substrates, and the two liquid crystal substrates are fixed in parallel so as to seal the space between the sealing material and the two liquid crystal substrates and irradiated with ultraviolet rays to be solidified. Provided is a method for sealing a liquid crystal substrate, and a liquid crystal encapsulation body obtained by encapsulating liquid crystal in a space surrounded by two liquid crystal substrates and the sealing material.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

(Alicyclic Epoxy Compound) The alicyclic epoxy compound used in the present invention is a compound having an alicyclic structure and an epoxy group bonded thereto, and has 3 or more carbon atoms, preferably 4 carbon atoms.
Or more, more preferably 5 or more and 50 or less, preferably 3
A compound having an epoxy group bonded to an alicyclic structure of 5 or less, more preferably 12 or less, and having a molecular weight of 100 or more, preferably 110 or more, more preferably 120 or more, 2000 or less, preferably 1500 or less, It is preferably 1000 or less.

If the molecular weight is too small, the alicyclic epoxy compound has high volatility, which significantly deteriorates the working environment and the processing characteristics during coating. If the molecular weight is too large, the viscosity of the composition becomes high, and it becomes difficult to apply the composition uniformly in a predetermined shape.

Specific examples of the alicyclic epoxy compound include:
General formula 1

Embedded image A compound represented by (for example, Araldite CY179 manufactured by Nippon Ciba Geigy) or the general formula 2

Embedded image A compound represented by (for example, Araldite CY178 manufactured by Nippon Ciba Geigy), a compound represented by the general formula 3

Embedded image Compound represented by (for example, Chisso Knox manufactured by Chisso
206), general formula 4

Embedded image Compound represented by (for example, Chisso Knox manufactured by Chisso
205), general formula 5

Embedded image A compound represented by the formula 6

[Chemical 6] A compound represented by the general formula 7

[Chemical 7] A compound represented by the general formula 8

Embedded image A compound represented by the general formula 9

Embedded image A compound represented by the general formula 10

Embedded image A compound represented by the general formula 11

Embedded image A compound represented by the general formula 12

[Chemical 12] A compound represented by the following general formula 13

Embedded image Examples thereof include compounds represented by.

(Aliphatic Glycidyl Ether Type Epoxy Compound) The aliphatic glycidyl ether type epoxy compound used in the present invention is a compound having a glycidyl ether bond at the terminal of the aliphatic compound, and has a molecular weight of 100 or more, preferably 110 or more, more preferably 120 or more and 2000 or less, preferably 1500 or less, more preferably 1000 or less.

If the molecular weight is too small, the aliphatic glycidyl ether type epoxy compound has high volatility, which significantly deteriorates the working environment and the processing characteristics during coating. If the molecular weight is too large, the viscosity of the composition becomes high, and it becomes difficult to apply the composition uniformly in a predetermined shape.

Specific examples of the aliphatic glycidyl ether type epoxy compound include monofunctional compounds such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, 2-methyloctyl glycidyl ether and glycidol; neopentyl glycol diglycidyl ether. , Glycerol diglycidyl ether, glycerol triglycidyl ether, ethylene glycol diglycidyl ether and other bifunctional compounds; trimethylolpropane polyglycidyl ether with a molecular weight of 2000 or less, 1,4-butanediol diglycidyl ether, polypropylene glycol di with a molecular weight of 2000 or less Glycidyl ether, polyethylene glycol diglycidyl ether with a molecular weight of 2000 or less, sodium glycol with a molecular weight of 2000 or less Polyfunctional compound having three or more functional, such as bi tall polyglycidyl ether; and the like. A bifunctional compound is preferable in terms of adhesive strength. In this case, monofunctional means having one epoxy group, bifunctional means having two epoxy groups, trifunctional means having three epoxy groups, and polyfunctional means having a plurality of epoxy groups. .

(Hydrophobic silica particles) The hydrophobic silica particles used in the present invention have a hydrophobicity of 60% or more, preferably 62% or more, more preferably 64% or more, in which silanol groups on the particle surface are replaced with hydrophobic groups. 100% or less, preferably 9
9.8% or less, more preferably 99.5% or less, the average particle size of primary particles is 1 nm or more, preferably 3 nm or more, more preferably 5 nm or more, 1 μm or less, preferably 10
The silica particles are 0 nm or less, and more preferably 20 nm or less.

It should be noted that the hydrophobicity is 1% of distilled water in a separating funnel.
1 g of silica particles was added to 00 g, shaken sufficiently with a shaker for 20 minutes, and then allowed to stand for 5 minutes,
It is expressed as the ratio of the visible light transmittance of the liquid phase to the visible light transmittance of distilled water before taking out the liquid phase from the lower part and adding silica particles. In addition, the primary particles are particles that are not agglomerated one by one. The particle size of the primary particles is obtained using a micrograph or the like.

Examples of the hydrophobic group used in the present invention include an alkyl group, a phenyl group, a trimethylsilyl group and an octylsilyl group. The method of substituting the silanol group on the surface of the silica particle with the hydrophobic group is not particularly limited, and for example, a method of treating with dimethyldichlorosilane (Japanese Patent Laid-Open Publication No. 6-68242)
1-50882), a method of treating with a hydrolysis solution of alkoxylane (Japanese Patent Publication No. 4-23673), and the like. The hydrophobic groups may be substituted for all or some of the silanol groups on the surface.

If the hydrophobicity is too low, the thixotropy is lowered, and if it is too high, the production is difficult. Further, it is difficult to produce silica particles having an average particle size of the primary particles that is too small, and it is difficult to obtain a uniform particle. When the average particle size of the primary particles is too large, it is difficult to make the sealing material have a uniform thickness. There is a problem of becoming.

Specific examples of the hydrophobic silica particles include Aerosil RX200 (hydrophobicity of about 65%, average particle size of 12n).
m silica particles, Nippon Aerosil Co., Ltd.), Aerosil RY200 (hydrophobicity about 65%, silica particles having an average particle size of 12 nm, Nippon Aerosil Co., Ltd.), Aerosil R
Examples thereof include Y200S (silica particles having a hydrophobicity of about 95% and an average particle diameter of 16 nm, Nippon Aerosil Co., Ltd.).

(Cationic Photopolymerization Initiator) The cationic photopolymerization initiator used in the present invention includes ultraviolet rays, α rays, β rays and γ.
It is a compound that liberates the Lewis acid catalyst by irradiating active energy rays such as rays. In the case of the composition of the present invention, the free Lewis acid catalyst causes the epoxy groups to react and cure.

Specific examples of the cationic photopolymerization initiator include BF ₄ ⁻ , PF ^{6 −} , FeCl ₄ ⁻ , AsF ₆ ⁻ , Sb.
Allyldiazonium salts having F ₆ ⁻ , SbCl ₆ ^{− and the} like as anions, for example, p-chlorobenzenediazonium hexafluorophosphate, p-methoxybenzenediazonium hexafluorophosphate, trichlorobenzenediazonium tetrafluoroborate, 2, 5-dichlorobenzenediazonium hexafluorophosphate, p-nitrobenzenediazonium hexafluoroantimonate, p-chlorobenzenediazonium hexafluoroarsenate, etc .;
Diaryl iodonium salts having BF ₄ ⁻ , PF ^{6 −} , AsF ₆ ⁻ , SbF ₆ ^{− and the} like as anions, for example, diphenyliodonium tetrafluoroborate, di (p-
Methylphenyl) iodonium tetrafluoroborate, di (o-nitrophenyl) such as iodonium ^{_{hexafluorophosphate; BF 4 -, PF 6-,}} AsF
₆ ^-, SbF ₆ ^- diaryl sill salts with such as an anion, e.g., diphenyliodonium sill tetrafluoroboronate Nate, di (o-carboxyphenyl) such iodosyl-hexafluorophosphate; triarylsulfonium salts, for example, Tri (p-methylphenyl) sulfonium tetrafluoroboronate,
Such as triphenylsulfonium · trifluoromethanesulfonate ^{_{Nate; BF 4 -, PF 6-,}} AsF 6 -, SbF
₆ ^- dialkyl phenacyl sulfonium salts having such as an anion, for example, dimethyl - phenacylsulfonium-tetrafluoroboronate Nate, diethyl - phenacylsulfonium tetrafluoroethylene antimonate Nate ^{_{like; BF 4 -, PF 6-,}} AsF ₆ ^-, SbF ₆ ^- dialkyl-4-hydroxyphenyl sulfonium salts having such as an anion, for example, dimethyl-4-hydroxyphenyl sulfonium, tetrafluoroboronate Nate,
Dimethyl- (3,5-dimethyl-4-hydroxyphenyl) sulfonium hexafluorophosphate,
Dimethyl-4-hydroxyphenyl sulfonium tetrafluoroethylene antimonate Nate; BF ₄ ^-, As
Triaryl selenium salts having F ₆ ⁻ , SbF ₆ ^{− and the} like as anions, for example, triphenyl selenium tetrafluoroboronate, triphenyl selenium hexafluoroarsenate, etc .; Iron arene salts; II
Examples include dicarbonyl chelates of group Ia, IVa, or Va; organometallic aluminum complexes; and the like, manganese decacarbonyl, ferrocene, zirconocene dichloride, and the like. Commercially available cationic photopolymerization initiators Adeka Optomer SP-150, Adeka Optomer SP-170 (these two types, manufactured by Asahi Denka Kogyo Co., Ltd.), Irgacure 261 (manufactured by Nippon Ciba Geigy Co., Ltd.), and Sila Cure UVI-6950,
Cylacure UVI-6970 (the above two types, manufactured by Union Carbide Japan Co., Ltd.) and the like can also be used.

(Photocurable composition) The photocurable composition of the present invention contains an alicyclic epoxy compound in an amount of 60% by weight or more, preferably 61% by weight or more, more preferably 62% by weight or more,
90% by weight or less, preferably 80% by weight or less, more preferably 70% by weight or less, aliphatic glycidyl ether type epoxy compound 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more, 40% by weight %Less than,
Preferably 35% by weight or less, more preferably 30% by weight
Below, 1% by weight or more of the hydrophobic silica particles, preferably 2
% By weight or more, more preferably 2.5% by weight or more and 10% by weight or less, preferably 8% by weight or less, more preferably 6% by weight or less.
% By weight, and 0.5% by weight or more, preferably 1% by weight or more, more preferably 2% by weight of the cationic photopolymerization initiator.
The content is not less than 10% by weight, preferably not more than 7% by weight, more preferably not more than 5% by weight.

If the amount of the alicyclic epoxy compound is too small, the thixotropy property is lowered, the fluidity at the time of applying the composition is lowered, and the non-fluidity until the bonding of the substrates is lowered, so that the sealing cannot be performed well. Sometimes,
If it is too large, the adhesive strength will decrease. If the amount of the aliphatic glycidyl ether type epoxy compound is too small, the adhesive strength will be lowered, and if it is too large, the heat resistance and the moisture resistance will be lowered. If the amount of the hydrophobic silica particles is too small, it will be difficult to maintain the coating shape, and if it is too large, it will be difficult to uniformly apply the particles to a predetermined shape in a short time. If the amount of the cationic photopolymerization initiator is too small, it is difficult for the curing to proceed, and the reaction tends to stop in an insufficiently cured state,
In that case, the adhesive strength decreases. In order to prevent this, it is necessary to increase the integrated light amount of ultraviolet irradiation, which causes problems such as energy efficiency, device scale, and irradiation time. If the amount of the cationic photopolymerization initiator is too much, the heat resistance and the moisture resistance will decrease.

The composition of the present invention has a viscosity measured by a BH viscometer at 20 rpm of 10 cps or more, preferably 100 cps or more, more preferably 500 cps or more,
40000 cps or less, preferably 20000 cps or less, more preferably 10000 cps or less, 5000 cps or more at 2 rpm, preferably 10000 cps or more, more preferably 20000 cps or more, 10000
It is 0 cps or less, preferably 80,000 cps or less, and more preferably 60,000 cps or less. 20r
If the value measured in pm is too large, the viscosity is too high for coating, and if it is too small, it becomes difficult to control the coating amount. 2 rp
If the value measured with m is too large, the value measured with 20 rpm tends to be large, and if it is too small, the viscosity cannot be maintained after coating and the coated state cannot be maintained.

If desired, a coupling agent, a coloring agent such as a dye or a pigment, a polymerization inhibitor, particles used as spacers, etc. may be added to the composition of the present invention.

The method of mixing the components to form a composition is not particularly limited, but in order to uniformly mix the components,
It is preferable to use a sand mill, dissolver, three rolls, ultrasonic homogenizer, ball mill or the like.

(Sealing Material) The photocurable composition of the present invention is useful as a sealing material. For example, a sealing material for a liquid crystal display, specifically, a liquid crystal is sealed between two liquid crystal substrates. It is excellent as a sealing material used for this purpose.

The liquid crystal substrate may be formed of glass, acrylic, a transparent resin such as a thermoplastic norbornene-based resin, or the like, and a conductive transparent electrode, a phase film or the like may be laminated on the surface thereof.

(Sealing Method) The sealing material of the present invention is applied onto at least one of two liquid crystal substrates, and the sealing material and
Two liquid crystal substrates are fixed in parallel and irradiated with active energy rays to be solidified so that the space is sealed by the liquid crystal substrates. Generally, ultraviolet rays are irradiated from the viewpoint of safety and energy efficiency.

The coating amount of the sealing material is preferably 1
μm or more, more preferably 2 μm or more, preferably 50
The thickness is not more than μm, more preferably not more than 40 μm. If it is too thin, sufficient adhesive strength cannot be obtained, and if it is too thick, it is difficult to completely cure it, and it is necessary to increase the amount of UV irradiation, resulting in poor production efficiency and energy efficiency.

The ultraviolet irradiation is 500 mJ / c in integrated light quantity.
m ² or more, preferably 800 mJ / cm ² or more, more preferably 1000 mJ / cm ² or more, 7000 mJ / cm ²
Or less, preferably 6000 mJ / cm ² or less, more preferably performed at 4000 mJ / cm ² or less. If the irradiation dose is too low, curing will be insufficient and the seal will not be sufficiently sealed. If the irradiation dose is too high, the sealing material and the liquid crystal substrate may deteriorate.

(Liquid crystal encapsulant) The liquid crystal encapsulant of the present invention comprises 2
A liquid crystal is sealed in a space surrounded by one liquid crystal substrate and a cured product of the sealing material of the present invention. The method for sealing the liquid crystal is not particularly limited, and after sealing with a syringe or the like, the liquid crystal is injected while bleeding the internal air, or after the liquid crystal is injected through an opening provided in a part of the sealing material. Block the opening.

The liquid crystal encapsulant can be used as a liquid crystal display by laminating a transparent conductive film, a phase film or the like on the liquid crystal substrate before or after encapsulation. The liquid crystal encapsulant of the present invention is easy to manufacture, and is excellent in the adhesive strength between the sealing material and the liquid crystal substrate, heat resistance, moisture resistance and the like.

(Aspect) As an aspect of the present invention, (1)
A photocurable composition comprising an alicyclic epoxy compound, an aliphatic glycidyl ether type epoxy compound, hydrophobic silica particles, and a cationic photopolymerization initiator, (2) an alicyclic epoxy compound and an alicyclic structure bonded thereto The composition according to (1), which is a compound having an epoxy group, (3) The alicyclic epoxy compound has an alicyclic structure having 3 to 50 carbon atoms and a molecular weight of 100 to 2000 (1) to
The composition according to (2), (4) the alicyclic epoxy compound is represented by general formula 1, general formula 2, general formula 3, general formula 4, general formula 5, general formula 6, general formula 7, general formula 8, The composition according to (1) to (3), which is a compound represented by the general formula 9, the general formula 10, the general formula 11, the general formula 12, or the general formula 13,
(5) The composition according to (1) to (4), wherein the aliphatic glycidyl ether type epoxy compound is a compound having a glycidyl ether bond at the terminal of the aliphatic compound, (6).
The composition according to (1) to (5), wherein the aliphatic glycidyl ether type epoxy compound has a molecular weight of 100 to 2000, and (7) the aliphatic glycidyl ether type epoxy compound is a bifunctional one. ) To (6), (8) The hydrophobic silica particles have a silanol group on the surface of the silica particle replaced with a hydrophobic group (1).
~ (7) composition, (9) hydrophobic silica particles,
(1) to (8) composition having a hydrophobicity of 60 to 100%, (10) hydrophobic silica particles having an average primary particle size of 0.001 to 1 μm (1) to
(9) The composition, (11) The cationic photopolymerization initiator liberates a Lewis acid catalyst upon irradiation with active energy rays, (1) to (10), (12).
Alicyclic epoxy compound 60 to 90% by weight, aliphatic glycidyl ether type epoxy compound 5 to 40% by weight,
The composition according to (1) to (11), which contains 1 to 10% by weight of hydrophobic silica particles and 0.5 to 10% by weight of a cationic photopolymerization initiator, and (13) a BH viscometer. Viscosity of 10-40,000cp at 20rpm
The composition according to (1) to (12), which is s, (14) B.
Viscosity measured by H-type viscometer is 5000-10 at 2 rpm
(1) to (13) which is 0000 cps,
(15) A sealing material composed of the composition according to (1) to (14), (16) a sealing material according to (15) is applied onto at least one of two liquid crystal substrates to form a sealing material and two sealing materials. A liquid crystal substrate sealing method in which two liquid crystal substrates are stacked in parallel and irradiated with active energy rays to be solidified so as to seal the space with the liquid crystal substrate of (17) (16) The sealing method according to (16), wherein the active energy ray is ultraviolet light (1)
6) to (17), the sealing method according to (19), wherein the cumulative amount of ultraviolet irradiation is from 500 to 7000 mJ / cm ² (18), (20) two liquid crystal substrates and (15) Examples include a liquid crystal sealing body obtained by sealing liquid crystal in a space surrounded by a sealing material, (21) a liquid crystal sealing body according to (20), which is a liquid crystal display.

[0034]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. The method for measuring the hydrophobicity is as described above, but shaking is performed for 5 minutes, 150 times / minute, and shaking width is 40 times.
mm vertical shaking.

Example 1 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate as an alicyclic epoxy compound (Araldite CY manufactured by Nippon Ciba-Geigy)
179) 70 parts by weight (about 64.8% by weight), 30 parts by weight (about 27.8) of 1,4-butanediol diglycidyl ether as an aliphatic glycidyl ether type epoxy compound.
% By weight), Aerosil RY2 as hydrophobic silica particles
00S (hydrophobicity 96%, average primary particle size 16 nm,
3.5 parts by weight (about 3.2% by weight) manufactured by Nippon Aerosil Co., Ltd., and 3 parts by weight (about 2.8% by weight) of a cationic photopolymerization initiator (triphenylsulfonium hexafluorophosphate), Use an ultrasonic homogenizer under the conditions of a high frequency output of 600 W and an oscillation frequency of 19.6 kHz, while cooling so that the temperature does not exceed 50 ° C.
Disperse and mix for a minute to make it even, and then use spacers (Sekisui Fine Chemical's polymer beads, Micropearl S
P-207, 1.5 parts by weight (about 1.4% by weight) of primary particles having an average particle size of 7 μm) were added and mixed sufficiently with a stirrer at room temperature to obtain a photocurable composition of the present invention. It was This composition is also the sealing material of the present invention.

When the viscosity of this sealing material was measured with a BH type viscometer, it was 4000 cps at 20 rpm and 45000 cps at 2 rpm.

A circular seal material having a thickness of 7.5 μm and a diameter of 5 mm is applied to the center of a glass plate having a thickness of 1 mm and 25 mm × 100 mm, and a cross shape is formed by overlapping with the center portion of a glass plate having the same size. The test piece was placed in such a manner and irradiated with ultraviolet rays of 100 mW / cm ² for 10 seconds to be cured to obtain a cured test piece. The distance between the two glass plates of the cured test piece was 7 μm. Pull in a direction perpendicular to the glass plate, JIS K 6
When the shear strength was measured according to 850, the shear strength was 210 kg / cm ² and the peel strength was 2.9 kg / cm ^2.
Met.

Curing test pieces obtained in the same manner were tested at 120 ° C. for 2 hours.
After maintaining under atmospheric pressure and water vapor saturation conditions for 3 hours, the same measurement was performed, and the shear strength was 200 kg / cm ² and the peel strength was 2.7 kg / cm ² .

The sealing material was dispensed using a dispenser with a line width of 1 mm, leaving one opening with a width of 2 mm on the outer periphery of the flat surface of a glass substrate having a thickness of 1 mm and 90 mm × 150 mm.
It was applied at a speed of 2 m / s so as to form a sealing material layer having a thickness of ± 0.05 mm and a thickness of 7.5 μm. Even after 10 minutes from the application, the as-applied state was maintained.

A glass substrate having the same size as the coated glass substrate was laminated so that the sealing material layer was between the glass substrates, and 100 mW / cm ² of ultraviolet light was applied by a high pressure mercury lamp.
It was irradiated for 0 seconds and cured. The cured sealant layer had a line width of 1 mm ± 0.1 mm and a thickness of 7 μm.

A liquid crystal is injected through the opening to prevent air from entering the sealant (Nippon Loctite, Loctite 3
50, an ultraviolet-curable modified acrylate) was used to seal the opening to obtain the liquid crystal encapsulant of the present invention.

Example 2 In the same manner as in Example 1 except that Aerosil RX200 (hydrophobicity 65%, average particle size of primary particles: 12 nm, manufactured by Nippon Aerosil Co., Ltd.) is used as the hydrophobic silica particles.
The sealing material of the present invention was obtained. This sealing material is 20 rpm
Was 4500 cps at 2 rpm and 43000 cps at 2 rpm.

When a cured test piece was manufactured in the same manner as in Example 1 using this sealing material, the gap between the glass plates was also 7
μm, and the shear strength measured using this is 215
kg / cm ² , peel strength 2.8 kg / cm ² , 120
Shear strength after holding for 3 hours under steam saturated conditions at 2 ° C., 2 atmospheres is 205 kg / cm ² , peel strength is 2.7 kg.
/ Cm ² .

The sealing material was dispensed by using a dispenser on the outer circumference of a glass substrate having a thickness of 1 mm, 90 mm × 150 mm, and having a line width of 1 mm ± 0.05 mm and a thickness of 7.5 μm.
When it was applied at a speed of 2 m / s so as to form a sealing material layer of m, the state as applied was maintained even 10 minutes after the application.

Example 3 70 parts by weight of vinylcyclohexenedioxide as an alicyclic epoxy compound (about 64.8% by weight) and 30 parts by weight of trimethylolpropane polyglycidyl ether as an aliphatic glycidyl ether type epoxy compound (about 27.
8% by weight), Aerosil RY as hydrophobic silica particles
An ultrasonic homogenizer was added to 3.5 parts by weight of 200S (about 3.2% by weight), and 3 parts by weight of a cationic photopolymerization initiator (triphenylsulfonium hexafluorophosphate) (about 2.8% by weight). High frequency output 600W,
Used at an oscillation frequency of 19.6 kHz and a temperature of 50 ° C
1.5 minutes by weight of spacers (polymer beads made by Sekisui Fine Chemical Co., Ltd., Micropearl SP-207, average particle size of primary particles 7 μm) 1.5 parts by weight (about 1. 4% by weight) was added and mixed well at room temperature with a stirrer to obtain a composition of the present invention. This composition is also the sealing material of the present invention.

When the viscosity of this sealing material was measured with a BH type viscometer, it was 3700 cps at 20 rpm and 38000 cps at 2 rpm.

When a cured test piece was produced in the same manner as in Example 1 using this sealing material, the glass plate spacing was 7
μm, and the shear strength measured using this is 215
kg / cm ² , peel strength 2.8 kg / cm ² , 120
Shear strength after holding under steam saturated conditions for 3 hours at 205 ° C., 205 kg / cm ² , peel strength 2.8 kg
/ Cm ² .

Also, the sealing material is dispensed using a dispenser on the outer periphery of a glass substrate having a thickness of 1 mm and 90 mm × 150 mm, a line width of 1 mm ± 0.05 mm and a thickness of 7.5 μ.
When it was applied at a speed of 2 m / s so as to form a sealing material layer of m, the state as applied was maintained even 10 minutes after the application.

Comparative Example 1 40 parts by weight of vinylcyclohexenedioxide (about 37.5% by weight) as an alicyclic epoxy compound and 60 parts by weight of trimethylolpropane polyglycidyl ether as an aliphatic glycidyl ether type epoxy compound (about 56.
3% by weight), Aerosil RY as hydrophobic silica particles
An ultrasonic homogenizer was used to add 3.5 parts by weight of 200S (about 2.8% by weight) and 3 parts by weight of a cationic photopolymerization initiator (triphenylsulfonium hexafluorophosphate) (about 3.2% by weight). High frequency output 600W,
Used at an oscillation frequency of 19.6 kHz and a temperature of 50 ° C
1.5 minutes by weight of spacers (polymer beads made by Sekisui Fine Chemical Co., Ltd., Micropearl SP-207, average particle size of primary particles 7 μm) 1.5 parts by weight (about 1. 4% by weight) was added and mixed well using a stirrer at room temperature to obtain a sealing material.

When the viscosity of this sealing material was measured with a BH type viscometer, it was 3500 cps at 20 rpm and 30,000 cps at 2 rpm.

When a cured test piece was produced in the same manner as in Example 1 using this sealing material, the gap between the glass plates was 7
μm, and the shear strength measured using this is 180
kg / cm ² , peel strength 1.9 kg / cm ² , 120
Shear strength after holding for 3 hours under steam saturated conditions at 2 ° C and atmospheric pressure of 130 kg / cm ² , peel strength of 1.2 kg
/ Cm ² .

Further, the sealing material was dispensed by using a dispenser on the outer periphery of a glass substrate having a thickness of 1 mm and 90 mm × 150 mm, a line width of 1 mm ± 0.05 mm, and a thickness of 7.5 μ.
When applied at a speed of 2 m / s so as to form a sealing material layer of m, the applied state was not retained after 10 minutes of application, and the line width had expanded to a maximum of 1.4 mm.

This sealing material was inferior in thixotropy, shear strength, peeling strength and high temperature and high humidity resistance.

Comparative Example 2 A sealing material was obtained in the same manner as in Example 1 except that Aerosil R972 (hydrophobicity 45%, average particle size of primary particles 16 nm, manufactured by Nippon Aerosil Co., Ltd.) was used as the hydrophobic silica particles. . This seal is 3500 at 20 rpm
cps at 2 rpm was 7000 cps.

Using a dispenser, this sealing material is
It was applied at a speed of 2 m / s so as to form a sealing material layer having a line width of 1 mm ± 0.05 mm and a thickness of 7.5 μm on the outer circumference of a glass substrate having a thickness of 1 mm and 90 mm × 150 mm, and 10 minutes after the application. The coated state was not retained and the line width was expanded to a maximum of 2.1 mm. This sealing material is inferior in thixotropy.

Comparative Example 3 Aerosil 300 (hydrophobicity 0
%, Primary particles having an average particle size of 7 nm, manufactured by Nippon Aerosil Co., Ltd.) were used in the same manner as in Example 1 to obtain a sealing material. This sealing material is 50000 cp at 20 rpm
s, 80,000 cps at 2 rpm.

This sealing material is dispensed by using a dispenser.
I tried to apply it at a speed of 2 m / s on a flat surface of a glass substrate having a thickness of 1 mm and 90 mm × 150 mm at a line width of 1 mm ± 0.05 mm and a thickness of 7.5 μm. Since it was expensive, it was difficult to apply, and it was possible to apply only in the form of broken lines. This sealing material is inferior in thixotropy.

Comparative Example 4 Epoxy compound (made by Yuka Shell Epoxy, Epicoat 8
28) 100 parts by weight, ethylene glycol monoethyl ether 5 parts by weight, modified aromatic amine (Nippon Gosei Kako,
Acmex H-94) 50 parts by weight, Aerosil 3
6 parts by weight of 00 was kneaded with a three-roll mill. Spacer (polymer beads made by Sekisui Fine Chemical Co., Ltd., Micropearl SP-207) was added to 100 parts by weight of this mixture.
Parts by weight were added and thoroughly mixed at room temperature with a stirrer to obtain a heat-curable composition.

The heat-curable composition was 15 rpm at 20 rpm.
000 cps and 90,000 cps at 2 rpm.

A glass plate having a thickness of 1 mm and a size of 25 mm × 100 mm has a circular shape with a thickness of 7.5 μm and a diameter of 5 mm at the center.
1.5 kg of this heat-curable composition is applied, and the glass plate of the same size is placed so as to form a cross, overlapping with the central part.
While being pressurized to / cm ² , the test piece was obtained by holding it at 160 ° C. for 1 hour for curing. The distance between the two glass plates of the cured test piece was 7 μm. When measured in the same manner as in Example 1, the shear strength was 220 kg / cm ² , the peel strength was 2.9 kg / cm ² , 120 ° C., 2 atm, and the shear strength after holding for 3 hours under steam saturation conditions was 200 kg / cm ² . c
The m ² and the peel strength were 2.6 kg / cm ² .

Using this dispenser, a mixture layer having a line width of 1 mm ± 0.05 mm and a thickness of 7.5 μm was formed on the outer periphery of a glass substrate having a thickness of 1 mm and 90 mm × 150 mm by using a dispenser. When the coating was performed at a speed of 2 m / s, the coated state was maintained even 10 minutes after the coating, but glass substrates of the same size were stacked so that the mixture layer was between the glass substrates. In total, pressurize to 160 ° C while applying pressure of 1.5 kg / cm ^2.
When the material was held for a while to be cured, a part of the material flowed and the width became 1.3 mm. This heat curable composition,
Excellent in high temperature and high humidity resistance, shear strength and peel strength, but poor in thixotropy.

Comparative Example 5 Acrylic compound (Viscote 5 manufactured by Osaka Organic Chemical Industry)
100 parts by weight, benzoin butyl ether 5 parts by weight, Aerosil
4 parts by weight of 300 was kneaded with a three-roll mill. Spacer (polymer beads made by Sekisui Fine Chemical Co., Ltd., Micropearl SP-207) was added to 100 parts by weight of this mixture.
5 parts by weight was added and thoroughly mixed at room temperature with a stirrer to obtain an ultraviolet curable acrylic composition.

This UV-curable acrylic composition is 20
25,000 cps at rpm, 45,000 cp at 2 rpm
It was s.

A composition was cured in the same manner as in Example 1 except that this ultraviolet-curable acrylic composition was used instead of the sealing material in Example 1. The distance between the two glass plates of the cured test piece was 7 μm. When measured in the same manner as in Example 1, the shear strength was 160 kg / cm ² , the peel strength was 1.8 kg / cm ² , 120 ° C., 2 atm, and the shear strength after holding under steam-saturated conditions for 3 hours was 90 kg / cm ² . c
The m ² and peel strength were 0.8 kg / cm ² .

Further, the ultraviolet curable acrylic composition was used with a dispenser to have a thickness of 1 mm and 90 mm × 150.
mm line width of 1 mm ± 0.05 on the outer circumference of the glass substrate.
mm so that the thickness of the sealant layer is 7.5 μm and 0.5
When applied at a speed of m / s, the as-applied state was maintained even 10 minutes after application.

This UV-curable acrylic composition was excellent in thixotropy, but inferior in shear strength, peeling strength and resistance to high temperature and high humidity.

[0067]

The sealing material of the present invention is excellent in thixotropy, shear strength, peeling strength, resistance to high temperature and high humidity, and easily obtains strong sealing property. When used as a sealing material for liquid crystal displays, etc., A good product can be obtained with high productivity.

Claims (4)

[Claims] 1. A photocurable composition comprising an alicyclic epoxy compound, an aliphatic glycidyl ether type epoxy compound, hydrophobic silica particles, and a cationic photopolymerization initiator. 2. A sealing material comprising the composition according to claim 1. 3. The sealing material according to claim 2 is applied onto at least one of the two liquid crystal substrates, and the two liquid crystal substrates are attached so that the space is sealed by the sealing material and the two liquid crystal substrates. A method of sealing liquid crystal substrates that are stacked in parallel and irradiated with ultraviolet rays to solidify. 4. A liquid crystal sealing body obtained by sealing liquid crystal in a space surrounded by two liquid crystal substrates and the sealing material according to claim 2.