TW201420735A - Liquid crystal sealing agent and liquid crystal display cell using same - Google Patents

Abstract

Provided is a liquid crystal sealing agent for use in a liquid crystal dropping process which, due to the particularly excellent adherence to an organic film such as an oriented film, does not readily peel from upper/lower substrates even in various environments, and further, has excellent fundamental characteristics as a liquid crystal sealing agent, such as low liquid crystal staining properties and heat resistance. This liquid crystal sealing agent is characterized in that, when the strength of adhesive bonding to an ITO substrate at 25 DEG C after curing for 1 hour under an atmosphere of 120 DEG C, following irradiation of 3000 mJ/cm2 ultraviolet rays, is taken as A [MPa], the strength of adhesive bonding at 120 DEG C after said curing is taken as B [MPa], and the strength of adhesive bonding to an ITO substrate at 25 C after curing with only 3000 mJ/cm<SP>2</SP> ultraviolet rays is taken as C [MPa], A, B and C satisfied the relational expressions shown by expressions (1) and (2) below. B ≥ 0.5 A (1) C ≥ 0.3 A (2).

Description

Liquid crystal sealing agent and liquid crystal display unit using the liquid crystal sealing agent

The present invention relates to a liquid crystal sealing agent used in a liquid crystal dropping method. More specifically, it relates to a liquid crystal sealing agent and a liquid crystal display unit using the liquid crystal sealing agent, which is excellent in adhesion to an organic film such as an alignment film (alignment film).

In recent years, as a method of manufacturing a liquid crystal display unit, a so-called liquid crystal dropping method has been proposed, which has a higher mass productivity (Patent Documents 1 and 2). Specifically, the liquid crystal dropping method is a manufacturing method in which a liquid crystal sealing agent is cured by dropping a liquid crystal on the inside of a crucible formed of a liquid crystal sealing agent formed on one substrate, bonding the other substrate, and then sealing the liquid crystal sealing agent.

However, in the liquid crystal dropping method, since the liquid crystal is in contact with the liquid crystal sealing agent before the liquid crystal sealing agent is hardened, the liquid crystal sealing agent may be infiltrated due to the pressure caused by the liquid crystal, and in the worst case, there are A flaw caused by a liquid crystal sealant may occur and become a problem. In order to solve this problem, it is necessary to increase the precision of the liquid crystal dropping amount. However, since the liquid crystal expands during the curing step of the liquid crystal sealing agent, that is, the liquid crystal, it is difficult to completely suppress the above-described infiltration phenomenon.

In order to suppress the above infiltration phenomenon, a technique is proposed which is used The rapid curing of the liquid crystal sealing agent is achieved by increasing the reaction rate of the liquid crystal sealing agent, or the viscosity of the liquid crystal sealing agent is increased during heating by using a gelling agent or the like (Patent Documents 3 and 4). These are reasonable techniques for the liquid crystal sealing agent to resist the pressure due to the expansion of the liquid crystal, but the pressure is nowhere to vent, and the upper and lower directions, that is, the direction in which the two substrates are peeled off, are increased. A new poor condition that causes substrate peeling occurs.

Further, the liquid crystal sealing agent which has been subjected to the above-mentioned increase in the reaction rate or the addition of the gelling agent has a large change over time, and many of them have problems in ease of use.

Also, nowadays, liquid crystal display elements are used in a very wide variety of Something in it. Therefore, it is necessary to produce a poor state even for a large temperature change or high humidity. This property is a characteristic that is applied evenly to the liquid crystal sealing agent, and does not cause peeling between the substrates due to a change in temperature, and is required to have resistance to high humidity or to prevent penetration of water. As a method for solving this problem, a technique of using a partially (meth)acrylated epoxy resin having a specific property or the like has been proposed (Patent Document 5). However, it has not yet been said to be perfect.

Moreover, the liquid crystal panel of the narrow frame design in recent years, due to the liquid crystal sealing The line width of the agent becomes thinner, and the problem of adhesion strength becomes more serious than before. That is, since the line width of the liquid crystal sealing agent is reduced, the conventional adhesive strength causes a problem that the upper and lower substrates are peeled off after the normal temperature and moisture resistance reliability test.

Moreover, recently, a liquid crystal sealing agent is disposed on a liquid above an orientation film or the like. The design of the crystal display unit has increased. However, in the conventional liquid crystal sealing agent, the adhesion to such an organic film cannot be said to be sufficient, and it becomes a problem to be solved.

As described above, there are various liquid crystal sealing agents for liquid crystal dropping methods. The problem, although being fully researched, has not yet been developed to solve these problems.

Further, the liquid crystal sealing agent for a liquid crystal dropping method must be excellent in general characteristics such as low liquid crystal contamination and high adhesion strength.

[Previous Technical Literature]

(Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. SHO63-179323

Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 10-239694

Patent Document 3: International Publication No. 2011/061910

Patent Document 4: Japanese Laid-Open Patent Publication No. 2006-23419

Patent Document 5: Japanese Laid-Open Patent Publication No. 2011-221168

The present invention provides a liquid crystal sealing agent and a liquid crystal display unit using the liquid crystal sealing agent, which is a liquid crystal sealing agent used in a liquid crystal dropping method, and has excellent adhesion to an organic film such as an oriented film, and thus In the various environments, peeling of the upper and lower substrates is less likely to occur, and low liquid crystal contamination, heat resistance, and the like are also excellent as basic characteristics of the liquid crystal sealing agent.

As a result of intensive investigation, the inventors of the present invention have found that a liquid crystal sealing agent which is excellent in adhesion strength to an organic film which is hardened after being irradiated with ultraviolet rays of 3000 mJ/cm ² and at 120 ° C. After the aging, the adhesion of the cured liquid crystal sealing agent to the ITO (indium tin oxide) substrate at 25 ° C is set to A [MPa], and the adhesion strength of the cured liquid crystal sealing agent at 120 ° C is set. When the liquid crystal sealing agent which is cured by ultraviolet rays of only 3000 mJ/cm ² is B [MPa] and the adhesion strength to the ITO (indium tin oxide) substrate is C [MPa] at 25 ° C, the above A, B And C have a certain relationship.

In the present specification, the term "(meth)acrylic acid" means "acrylic acid and/or methacrylic acid".

That is, the present invention relates to the following 1) to 13).

1)

A liquid crystal sealing agent for liquid crystal dropping method, which is cured by irradiating ultraviolet rays of 3000 mJ/cm ² and cured at 120 ° C for 1 hour, and then curing the cured liquid crystal sealing agent at 25 ° C for ITO (indium tin oxide) The adhesive strength of the substrate is A [MPa], and the adhesion strength of the liquid crystal sealing agent after curing at 120 ° C is B [MPa], and the liquid crystal sealing is performed only by ultraviolet rays of 3000 mJ/cm ² . When the adhesive strength of the ITO (indium tin oxide) substrate is C [MPa] at 25 ° C, the above A, B, and C satisfy the relationship represented by the following formulas (1) and (2): B ≧ 0.5 ×A (1)

C≧0.3×A (2).

2)

The liquid crystal sealing agent for liquid crystal dropping method according to the above-mentioned 1), wherein the liquid crystal sealing agent which has been cured by ultraviolet rays of only 3,000 mJ/cm ² has an adhesion strength to an ITO (indium tin oxide) substrate at 120 ° C. In the case of D [MPa], the above A and D satisfy the relationship represented by the following formula (3): D ≧ 0.3 × A (3).

3)

The liquid crystal sealing agent for liquid crystal dropping method according to the above 1), which comprises: component (a) (meth) acrylated epoxy resin, component (b) photopolymerization initiator, component (c) inorganic filler, And component (d) an organic hydrazine compound.

4)

The liquid crystal sealing agent for a liquid crystal dropping method according to the above 3), which further contains a component (e) a thermal radical polymerization initiator.

5)

The liquid crystal sealing agent for liquid crystal dropping method according to the above 4), wherein the component (e) thermal radical polymerization initiator is 1,2-bis(trimethyldecyloxy)-1,1,2 , 2-tetraphenylethane.

6)

A liquid crystal sealing agent for a liquid crystal dropping method according to the above 3), which further comprises a component (f) epoxy resin.

7)

The liquid crystal sealing agent for a liquid crystal dropping method according to the above 3), which further contains a component (g) decane coupling agent.

8)

The liquid crystal sealing agent for a liquid crystal dropping method according to the above 7), wherein the component (g) is an amino decane coupling agent.

9)

a liquid crystal sealing agent for liquid crystal dropping method according to the above 7), wherein Component (g) is a mixture of an amine decane coupling agent and an epoxy decane coupling agent.

10)

The liquid crystal sealing agent for a liquid crystal dropping method according to the above 3), which further contains a compound having a phenolic hydroxyl group as component (h).

11)

The liquid crystal sealing agent for a liquid crystal dropping method according to the above 10, wherein the component (h) is a phenolic phenol resin.

12)

A liquid crystal display unit manufacturing method according to any one of the above-mentioned 1) to 11), wherein a liquid crystal display unit comprising two substrates is formed by a liquid crystal dropping method according to any one of the above 1) to 11) After the liquid crystal is dropped on the inside of the crucible formed of the agent, the other substrate is bonded, and then the liquid crystal sealing agent for liquid crystal dropping method is cured by ultraviolet rays and/or heat.

13)

A liquid crystal display unit obtained by curing a liquid crystal sealing agent for a liquid crystal dropping method according to any one of the above 1) to 11), which is obtained by curing a liquid crystal sealing agent according to any one of the above 1) to 11).

The liquid crystal sealing agent for a liquid crystal dropping method of the present invention is excellent in adhesion to an organic film such as an oriented film, and is not easily peeled off in various environments. Therefore, a liquid crystal display unit that can be used in a wide variety of environments can be realized. Further, since the general characteristics such as low liquid crystal contamination, heat resistance, heat cycle resistance, and moisture resistance are also excellent, a liquid crystal display unit excellent in long-term reliability can be realized.

The liquid crystal sealing agent for liquid crystal dropping method of the present invention (hereinafter simply referred to as "liquid crystal sealing agent") is cured by irradiating ultraviolet rays of 3000 mJ/cm ² and then curing at 120 ° C for 1 hour, and then curing the liquid crystal after curing. When the sealant is at 25 ° C, the adhesion strength to the ITO (indium tin oxide) substrate is A [MPa], and the adhesion strength of the liquid crystal sealing agent after curing at 120 ° C is B [MPa], and only When the liquid crystal sealing agent hardened by ultraviolet rays of 3000 mJ/cm ² is C [MPa] when the adhesion strength to the ITO (indium tin oxide) substrate is 25 ° C, the above A, B, and C satisfy the following formula (1). (2) The relationship represented by: B≧0.5×A (1)

C≧0.3×A (2).

The above formula (1) means that after the irradiation with ultraviolet rays of 3000 mJ/cm ² and hardening at 120 ° C for 1 hour, the adhesive strength at 120 ° C is 50% of the adhesive strength at 25 ° C (50). %)the above. The liquid crystal sealing agent having such a characteristic can be stably produced without causing peeling of the upper and lower substrates in the heating step in the production of the liquid crystal display unit. Further, as in the case of the heat cycle test, even when the state is exposed to the high temperature and the low temperature alternately, the substrate peeling does not occur and the stability is maintained.

Further, the above formula (2) refers to an adhesive strength in an environment of 25 ° C after being cured by irradiation with only ultraviolet rays of 3,000 mJ/cm ² , and is hardened by irradiation with ultraviolet rays of 3,000 mJ/cm ² and at 120 ° C for 1 hour. After that, the adhesive strength at 30 ° C was 30% (30%) or more. The liquid crystal sealing agent having such a characteristic has a small hardening shrinkage in the ultraviolet irradiation step in the production of the liquid crystal display unit, that is, even if the stress applied to the organic film is small on the organic film, excellent performance can be achieved. Adhesive.

Further, after irradiating ultraviolet rays of 3,000 mJ/cm ² and curing in an environment of 120 ° C for 1 hour, the adhesion strength of the cured liquid crystal sealing agent to the ITO (indium tin oxide) substrate at 25 ° C was set to A [ MPa]; The adhesion strength of the liquid crystal sealing agent which was cured by ultraviolet rays of only 3000 mJ/cm ² to the ITO (indium tin oxide) substrate at 120 ° C was D [MPa]. In this case, the effect of the present invention is particularly remarkable in the case where the relationship expressed by the following formula (3) is satisfied.

D≧0.3×A (3)

The adhesion strength to an ITO (indium tin oxide) substrate at 25 ° C means the adhesion strength in an environment of 25 ° C. The method of measuring the adhesion strength is to use the adhesion strength in the shear direction. For example, a small amount of a liquid crystal sealing agent is applied onto a 5 cm square ITO (indium tin oxide) substrate, and then a 1.5 mm square glass wafer (cut by EAGLE XG: CORNING Co., Ltd., 1.5 mm square) is bonded using a tweezers. The test piece was irradiated with ultraviolet rays of 3000 mJ/cm ² , placed in a hot air oven set at 120 ° C for 1 hour, and heat-hardened. For this test piece (a glass wafer to be bonded), the adhesion strength can be measured using a bond tester (SS-30WD: Sejin Corporation). In the present case, the value of the adhesive strength thus obtained is defined as A [MPa]. In addition, the ITO (indium tin oxide) substrate used was cut into 5 cm squares and cut into 470 × 370 × 0.7 SP30 ITO (manufactured by GEOMATEC Co., Ltd.).

The so-called adhesive strength at 120 ° C is the test after hardening The adhesion strength measured by heating the sheet to 120 ° C was measured in the same manner as described above. As a method of heating to 120 ° C, the method of heating the measurement stage of the measuring device of the adhesion strength to 120 ° C is simple. In the present case, the value of the adhesive strength thus obtained is defined as B [MPa].

The adhesion strength of the liquid crystal sealing agent which is hardened by ultraviolet rays of only 3000 mJ/cm ² to the ITO (indium tin oxide) substrate at 25 ° C is that the liquid crystal sealing agent is not heat-hardened during the production of the test piece. The adhesive strength measured by the prepared test piece was a value measured in an environment of 25 °C. Further, the measurement itself was carried out in the same manner as described above. In the present case, the value of the adhesive strength thus obtained is defined as C [MPa].

The adhesion strength of the liquid crystal sealing agent which is hardened by ultraviolet rays of only 3000 mJ/cm ² to the ITO (indium tin oxide) substrate at 120 ° C is that the liquid crystal sealing agent is not heat-hardened during the production of the test piece. The adhesive strength measured by the prepared test piece was a value measured in an environment of 120 °C. Further, the measurement itself was carried out in the same manner as described above. In the present case, the value of the adhesive strength thus obtained is defined as D [MPa].

The present invention is a liquid crystal sealing agent for a liquid crystal dropping method. In the liquid crystal drop In the lower working method, in the manufacturing step of the liquid crystal display unit, there is generally a step of irradiating ultraviolet rays, and a large stress is accumulated between the liquid crystal sealing agent hardened in this step and the organic film such as the alignment film. Therefore, when such a liquid crystal dropping method is carried out, it is very effective to use the liquid crystal sealing agent of the present invention.

The liquid crystal sealing agent of the present invention is a liquid crystal droplet having the above characteristics The liquid crystal sealing agent used in the following method is not particularly limited, but contains components (a) (meth)acrylated epoxy resin, component (b) photopolymerization initiator, component (c) inorganic filler, and component (d). The case of an organic acid hydrazide compound is a particularly preferred aspect. The liquid crystal sealing agent containing these components has low contamination property with respect to liquid crystals, and is excellent in the liquid crystal dropping method.

The component (a) (meth) acrylated epoxy resin can be obtained by a well-known reaction of an epoxy resin and (meth)acrylic acid. For example, by adding a specific equivalent ratio of (meth)acrylic acid to a catalyst (for example, benzyldimethylamine, triethylamine, benzyltrimethylammonium chloride, triphenylphosphine, three) Benzoquinone, etc., with polymerization inhibitors (eg methoxyphenol, hydroquinone, methyl hydroquinone, thiophene (phenothiazine), dibutylhydroxytoluene, etc., obtained by, for example, an esterification reaction at 80 to 110 °C. The epoxy resin to be used as a raw material is not particularly limited, and is preferably a bifunctional or higher epoxy resin, and examples thereof include diglycidyl ether of resorcinol (Resorcin) and bisphenol A type ring. Oxygen resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolac type epoxy resin, bisphenol A phenol type epoxy resin, bisphenol F phenol type epoxy Resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, intramethylene urea resin, isocyanuric epoxy resin, A phenolic novolac type epoxy resin of a trisphenol methane skeleton, and a diglycidyl ether compound of a difunctional phenol, a diglycidyl ether compound of a difunctional alcohol, and a halide or a hydride thereof. Among these, from the viewpoint of liquid crystal contamination, a bisphenol type epoxy resin, a novolac type epoxy resin, and a diglycidyl ether of resorcin (resorcin) are more preferable.

The content of the above component (a) (meth) acrylated epoxy resin, In view of the workability and physical properties of the obtained liquid crystal sealing agent, the liquid crystal sealing agent is usually about 25 to 80% by mass, preferably 25 to 75% by mass.

The component (b) photopolymerization initiator is not particularly limited as long as it is a compound that initiates a chain polymerization reaction by irradiation of ultraviolet rays or visible light, and examples thereof include, for example, benzyldimethylketal, 1-hydroxycyclohexyl phenyl ketone, diethyl thioxanthone, benzophenone, 2-ethyl hydrazine, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(A Thio)phenyl]-2-(N-morpholinyl)-1-propane, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, diphenyl Dithioethers and the like. Specifically, IRGACURE ^RTM 651, 184, 2959, 127, 907, 396, 379EG, 819, 784, 754, 500, OXE01, OXE02, DAROCURE ^RTM 1173, LUCIRIN ^RTM TPO (above, BASF); SEIKUOL ^RTM Z, BZ, BEE, BIP, BBI (above, manufactured by Seiko Chemical Co., Ltd.). In addition, the "RTM" superscripted in this manual means a registered trademark.

Further, from the viewpoint of liquid crystal contamination, it is preferred to use a (meth)acrylic group in the molecule, and for example, 2-methylpropenyloxyethyl isocyanate and 1-[4-(2-hydroxyl) are suitably used. A reaction product of ethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one. This compound can be produced by the method described in International Publication No. 2006/027982.

The content of the component (b) photopolymerization initiator which can be used in the liquid crystal sealing agent of the present invention is usually 0.01 to 15% by mass, preferably 0.02 to 10%, when the entire liquid crystal sealing agent is 100% by mass. quality%.

As the component (c) inorganic filler, molten cerium oxide, Crystalline cerium oxide, cerium carbide, cerium nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesia, zirconia, aluminum hydroxide, magnesium hydroxide , calcium citrate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably molten cerium oxide, crystalline cerium oxide, cerium nitride Boron nitride, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium citrate, aluminum citrate, more preferably molten cerium oxide, crystalline cerium oxide, aluminum oxide ,talc. These inorganic fillers may be used in combination of two or more kinds. In particular, when it is used as an adhesive for the following liquid crystal display unit, when the average particle diameter is too large, it is difficult to form a gap when the upper and lower glass substrates are bonded during the manufacture of the liquid crystal display unit with a narrow gap, so that 3 μm or less is suitable, and preferably 2 μm or less. The particle size can be measured by a laser diffraction/scattering particle size analyzer (dry type) (manufactured by SEISHIN Co., Ltd.; LMS-30).

The content of the above component (c) inorganic filler, in the liquid of the present invention When the total amount of the crystal sealant is 100% by mass, it is usually 1 to 60% by mass, preferably 5 to 50% by mass. When the content of the component (c) inorganic filler is too small, the adhesive strength is lowered and the moisture resistance reliability is also deteriorated, so that the adhesion strength after moisture absorption is also largely lowered. On the other hand, when the content of the component (c) inorganic filler is too large, when it is used as an adhesive for a liquid crystal display unit, a cell gap may not be formed.

The component (d) organic ruthenium compound is an aromatic or aliphatic compound having a functional group such as -NHNH _{2 in} such a manner that ruthenium is reacted with an organic acid. Examples of the aromatic hydrazine include diterpene terephthalate, diammonium isophthalate, diammonium 2,6-naphthoate, 2,6-pyridine dioxime, 1,2,4- Benzoquinone, tetramethylphosphonium 1,4,5,8-naphthoate, tetrabenzal tetrahydrofuranate, and the like. Further, examples of the aliphatic hydrazine compound include formazan, acetamidine, acetonide, bismuth oxalate, diammonium malonate, diterpene succinate, and glutaric acid. Bismuth, diammonium adipate, diammonium pimelate, diterpene sebacate, 1,4-cyclohexanedioxime, diterpenic tartrate, diterpenic acid malate, iminodiyl Diterpene acetate, N, N'-hexamethylene bis-semicarbazone, triterpenoid citrate, trimethyl sulfatriacetate, triterpene Cyclohexane tricarboxylate, 1,3-double (肼Carbocarbonylethyl)-5-isopropylhydantoin or the like having an intramethylene uregar skeleton, preferably having a carbendazim urea skeleton (the carbon atom of the uremone ring is replaced by an isopropyl group) a bismuth compound, a compound having an isocyanuric acid skeleton, and the like. Examples of the compound having an isocyanuric acid skeleton include ginseng (1-fluorenylcarbonylmethyl)isocyanurate, ginseng (2-mercaptocarbonylethyl)isocyanurate, and ginseng (2-oxime). Alkylcarbonylethyl)isocyanurate, ginseng (3-mercaptocarbonylpropyl)isocyanurate, bis(2-mercaptocarbonylethyl)isocyanurate, and the like. From the balance of hardening reactivity and potential, it is preferably diammonium isophthalate, diammonium malonate, diterpene adipate, ginseng (1-mercaptocarbonylmethyl) isocyanuric acid. Acid ester, ginseng (2-mercaptocarbonylethyl) isocyanurate, ginseng (2-mercaptocarbonylethyl) isocyanurate, ginseng (3-mercaptocarbonylpropyl) isocyanurate Particularly preferred are diammonium malonate, diterpene sebacate, and bis(2-mercaptocarbonylethyl)isocyanurate. When the total amount of the component (a) (meth) acrylated epoxy resin is 100 parts by mass, the content of the component (d) organic cerium compound is 1 to 20 parts by mass. The case is preferably 2 to 10 parts by mass, and may be used in combination of 2 or more types.

The liquid crystal sealing agent of the present invention may further contain a component (e) a thermal radical polymerization initiator as needed.

The component (e) thermal radical polymerization initiator is not particularly limited as long as it is a compound which initiates a chain polymerization reaction by generating a radical by heating, and examples thereof include an organic peroxide, an azo compound, and a benzoin compound. A benzoin ether compound, an acetophenone compound, a benzopinacol or the like is preferably used as the benzopinacol. For example, as an organic peroxide, Kayamek ^RTM A, M, R, L, LH, SP-30C, Perkadox CH-50L, BC-FF, Cadox B-40ES, Perkadox 14, Trigonox ^RTM 22-70E, 23 can be purchased. -C70, 121, 121-50E, 121-LS50E, 21-LS50E, 42, 42LS, Kayaester ^RTM P-70, TMPO-70, CND-C70, OO-50E, AN, Kayabutyl ^RTM B, Perkadox 16, Kayacarbon ^RTM BIC-75, AIC-75 (above is made by Akzo Co., Ltd.); PERMEK ^RTM N, H, S, F, D, G, PERHEXA ^RTM H, HC, TMH, C, V, 22, MC, PERCURE Commercial products such as ^RTM AH, AL, HB, PERBUTYL ^RTM H, C, ND, L, PERCUMYL ^RTM H, D, PEROYL ^RTM IB, IPP, PEROCTA ^RTM ND (above, Nippon Oil Co., Ltd.). Further, as the azo compound, commercially available products such as VA-044, V-070, VPE-0201, VSP-1001, etc. (the above is manufactured by Wako Pure Chemical Industries, Ltd.) can be purchased.

As the component (e) thermal radical polymerization initiator, a benzopinacol-based thermal radical polymerization initiator (including a chemical modification of benzopinacol) is preferred. Specific examples thereof include benzopinacol, 1,2-dimethoxy-1,1,2,2-tetraphenylethane, and 1,2-diethoxy-1,1,2. 2-tetraphenylethane, 1,2-diphenyloxide Base-1,1,2,2-tetraphenylethane, 1,2-dimethoxy-1,1,2,2-tetrakis(4-methylphenyl)ethane, 1,2-di Phenoxy-1,1,2,2-tetrakis(4-methoxyphenyl)ethane, 1,2-bis(trimethyldecyloxy)-1,1,2,2-tetraphenyl Ethane, 1,2-bis(triethyldecyloxy)-1,1,2,2-tetraphenylethane, 1,2-bis(tertiary butyldimethylmethylalkoxy)-1 1,1,2,2-tetraphenylethane, 1-hydroxy-2-trimethyldecyloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-triethyldecane Oxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-tributylbutylmethyloxyl-1,1,2,2-tetraphenylethane, and the like. Preferred is 1-hydroxy-2-trimethyldecyloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-triethyldecyloxy-1,1,2,2 -tetraphenylethane, 1-hydroxy-2-tributyl dimethyl decyloxy-1,1,2,2-tetraphenylethane, 1,2-bis(trimethyldecyloxy) -1,1,2,2-tetraphenylethane, more preferably 1-hydroxy-2-trimethyldecyloxy-1,1,2,2-tetraphenylethane, 1,2- Bis(trimethyldecyloxy)-1,1,2,2-tetraphenylethane, particularly preferably 1,2-bis(trimethyldecyloxy)-1,1,2,2-tetra Phenylethane.

The above benzopinacol is sold from Tokyo Chemical Industry Co., Ltd., and Wako Pure Chemical Industries Co., Ltd., and the like. Further, a compound obtained by etherifying a hydroxyl group of benzopinacol can be easily synthesized by a known method. Further, a compound obtained by subjecting a hydroxyl group of a benzopinacol to a decyl ether can be synthesized by heating a corresponding benzopinacol with various decylating agents under an alkaline catalyst such as pyridine. . The decylating agent may, for example, be a trimethyl chloroalkylene (TMCS), hexamethyldioxane (HMDS) or N,O-bis(trimethylnonane) which is generally known. Trifluoroacetamide (BSTFA), and triethyl decylating agent, namely triethyl chlorodecane (TECS), tertiary butyl dimethyl methacrylate, ie, tertiary butyl methyl decane (TBMS), etc. . These reagents It can be easily purchased by the market of bismuth derivative manufacturers and the like. The amount of the reaction of the alkylating agent is preferably 1.0 to 5.0 times the molar amount of the hydroxyl group of the compound of 1 mole. More preferably 1.5 to 3.0 times Mo. If it is less than 1.0 times Moule, the reaction time becomes long due to poor reaction efficiency, and thus thermal decomposition is promoted. If it is more than 5.0 times Mo, the separation deteriorates or becomes difficult to refine at the time of recovery.

Ingredient (e) a thermal radical polymerization initiator, preferably a particle size reduction And dispersed evenly. When the average particle diameter is too large, it is difficult to form a gap when the liquid crystal display unit having a narrow gap is formed, and the gap is not easily formed when the upper and lower glass substrates are bonded. Therefore, it is preferably 5 μm or less, and more preferably 3 μm or less. Further, although it may be reduced without limitation, the lower limit is usually about 0.1 μm. The particle size can be measured by a laser diffraction/scattering particle size analyzer (dry type) (manufactured by SEISHIN Co., Ltd.; LMS-30).

The content of the component (e) thermal radical polymerization initiator, which will be the present invention When the total amount of the liquid crystal sealing agent is 100% by mass, it is preferably about 0.001 to 0.5% by mass.

The liquid crystal sealing agent of the present invention may further contain a component (f) as needed Epoxy resin.

The component (f) epoxy resin is not particularly limited, but is preferably one which is less polluting or solubility to liquid crystal. Examples of suitable epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and diglycidyl ether of resorcinol (redozin). , phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A phenolic epoxy resin, bisphenol F phenolic epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, shrinkage Glyceride type epoxy resin, glycidylamine type epoxy resin, intramethylene urea cycle Oxygen resin, isocyanuric acid type epoxy resin, phenolic novolac type epoxy resin having a trisphenol methane skeleton, and other diglycidyl ether compounds of difunctional phenols, diglycidyl ether of difunctional alcohols, And such halides, hydrides, and the like.

The content of the component (f) epoxy resin is considered as the liquid crystal sealant The liquid crystal sealing agent is usually about 25 to 80% by mass, preferably 25 to 75% by mass, depending on the industrial properties and physical properties. Further, among the sum of the component (a) (meth) acrylated epoxy resin and the component (f) epoxy resin, the component (f) epoxy resin accounts for 1 to 30% by mass, which is a preferred aspect of the present invention. First, it is more preferably 5 mass% to 15 mass%.

The liquid crystal sealing agent of the present invention can be used as component (g) decane coupling Agent, to seek further improvement in adhesion strength. Examples of the component (g) decane coupling agent include an amino decane coupling agent, an epoxy decane coupling agent, a decyl decane coupling agent, a vinyl decane coupling agent, a decyl methacrylate coupling agent, a decane methacrylate coupling agent, and a ureido group. A decane coupling agent or the like. Among these, an amine decane coupling agent and an epoxy decane coupling agent are preferable, and the effect of the present invention is more remarkably obtained in the case where an amino decane coupling agent and an epoxy decane coupling agent are used in combination. Specific examples of the decane coupling agent include 3-glycidoxypropyltrimethoxydecane and 3-glycidoxypropylmethyldimethoxydecane as the epoxy decane coupling agent. 3-glycidoxypropylmethyldiethoxydecane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, etc., as the amine decane coupling agent, N-benzene --γ-aminopropyltrimethoxydecane, N-(2-aminoethyl) 3-aminopropylmethyldimethoxydecane, N-(2-aminoethyl)3-amine Propylmethyltrimethoxydecane, N-2-(aminoethyl)-3-aminopropyl Trimethoxy decane, 3-aminopropyltriethoxy decane, N-(2-(vinylbenzylamino)ethyl) 3-aminopropyltrimethoxydecane ruthenate, etc. Examples of the decane coupling agent include 3-mercaptopropyltrimethoxydecane. Examples of the vinyl decane coupling agent include vinyltrimethoxydecane. Examples of the decane coupling agent include 3-propenyloxypropane. Examples of the decyl methacrylate coupling agent include 3-methacryloxypropyltrimethoxydecane and the like, and the ureido decane coupling agent may, for example, be 3-ureidopropyltriene. Ethoxy decane and the like. Since these decane coupling agents have been sold by Shin-Etsu Chemical Co., Ltd., etc. in KBM series, KBE series, etc., they can be easily purchased from the market. Among these, a preferred decane coupling agent is N-2-(aminoethyl)-3-aminopropyltrimethoxydecane (KBM-603 Shin-Etsu Chemical Co., Ltd.), 3-glycidol Ethoxypropyltrimethoxydecane (manufactured by S-510 CHISSO Co., Ltd.) is more preferably used in combination. When the total amount of the liquid crystal sealing agent of the present invention is 100% by mass, the content of the component (g) of the decane coupling agent is preferably 0.05 to 3% by mass.

The liquid crystal sealing agent of the present invention can be phenolic using component (h) A compound of a hydroxyl group is used to further improve the adhesion strength. Examples of the compound having a phenolic hydroxyl group include bisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol S, 4,4-biphenylphenol, and 2,2,6,6-tetramethyl- 4,4-biphenylphenol, 2,2-methylene-bis(4-methyl-6-tertiary butylphenol), ginseng (hydroxyphenyl)methane, pyrogallol, with diamethylene a phenol having a fluorenyl skeleton, a phenol having an anthracene skeleton such as a phenol skeleton, a polyphenol compound such as a phenolated polybutadiene, or a phenol, a cresol or an ethylphenol; Various kinds of butyl phenols, octyl phenols, bisphenol A, allyl phenols, brominated bisphenol A, bisphenol F, bisphenol S, naphthols, etc. Phenolic resin having phenol as a raw material; phenolic phenol resin having a benzene dimethyl skeleton; phenolic phenol resin having a dicyclopentadiene skeleton; phenolic phenol resin such as a phenolic phenol resin having an anthracene skeleton; phenol, cresol , ethyl phenols, butyl phenols, octyl phenols, and the like. Among these, a phenolic phenol resin is preferred.

In the liquid crystal sealing agent of the present invention, according to further needs, Monomers of (meth) acrylate and/or oligomers are used. Examples of such monomers and oligomers include a reaction product of dipentaerythritol and (meth)acrylic acid, a reaction product of dipentaerythritol-caprolactone and (meth)acrylic acid, and the like, as long as it is a liquid crystal. There are no special restrictions on the low polluting people.

In the liquid crystal sealing agent of the present invention, it can be formulated according to further needs A hardening accelerator such as an organic acid or imidazole, an organic filler, or an additive such as a pigment, a coating agent, an antifoaming agent, or a solvent.

As an example of a method of obtaining the liquid crystal sealing agent of the present invention, There are ways as shown below. First, in the component (a) (meth) acrylated epoxy resin, the dissolved component (b) photopolymerization initiator is heated, and the dissolved component (f) epoxy resin is heated as needed, and the component (h) has a phenolic hydroxyl group. Compound. After cooling to room temperature, the component (c) inorganic filler, component (d) organic hydrazine compound is added, and if necessary, component (e) thermal radical polymerization initiator, component (g) decane coupling agent is added, and organic is further added. The filler, the antifoaming agent, the leveling agent, the solvent, and the like are uniformly mixed by a well-known mixing device such as a three-roll mill, a sand mixer, a ball mill, etc., and are filtered by a metal mesh to enable The liquid crystal sealing agent of the present invention is produced.

In the liquid crystal display unit of the present invention, a pair of substrates on which specific electrodes have been formed are disposed oppositely at a predetermined interval, and the liquid crystal sealing agent of the present invention is used to seal the periphery and seal the liquid crystal in the gap. The type of liquid crystal to be sealed is not particularly limited. Here, the substrate is composed of a combination substrate which is made of glass, quartz, plastic, tantalum or the like and has at least one side having light transmissivity. In the liquid crystal sealing agent of the present invention, after a spacer such as a glass fiber (gap control material) is added, a dispenser or a screen printing apparatus is used for one of the pair of substrates. After the liquid crystal sealing agent is applied, it is pre-cured at 80 to 120 ° C as needed. Thereafter, the liquid crystal was dropped on the inside of the crucible composed of the liquid crystal sealing agent, and another glass substrate was superposed in a vacuum to form a gap. After the gap is formed, the liquid crystal display unit of the present invention can be obtained by hardening at 90 to 130 ° C for 1 to 2 hours. Moreover, when it is used as a photothermal type, the liquid crystal sealing agent is irradiated with ultraviolet rays by an ultraviolet irradiation machine, and it is photocured. The ultraviolet irradiation amount is preferably from 500 to 6,000 mJ/cm ² , more preferably from 1,000 to 4,000 mJ/cm ² . Thereafter, the liquid crystal display unit of the present invention can be obtained by curing at 90 to 130 ° C for 1 to 2 hours as needed. The liquid crystal display unit of the present invention thus obtained has no display failure due to liquid crystal contamination, and is excellent in adhesion and moisture resistance reliability. Examples of the spacer include glass fibers, ceria beads, polymer beads, and the like. The diameter, although depending on the purpose, is usually 2 to 8 μm , preferably 4 to 7 μm . The amount of use is usually from 0.1 to 4% by mass, preferably from 0.5 to 2% by mass, more preferably from 0.9 to 1.5% by mass, based on the liquid crystal sealing agent of the present invention.

The liquid crystal sealing agent of the present invention has high adhesion strength after hardening due to ultraviolet rays, and has a small difference in adhesion strength at normal temperature and adhesion strength in a heating environment, and therefore has excellent adhesion to an organic film such as an alignment film. Can be made A stable liquid crystal display unit and a liquid crystal display unit excellent in long-term reliability. Further, since the cured product of the liquid crystal sealing agent of the present invention is stable in the heat cycle test and excellent in heat resistance and moisture resistance, it is possible to realize a liquid crystal display unit having excellent reliability. Further, the heat resistance can be confirmed by measuring the glass transition temperature, and the moisture resistance can be confirmed by measuring the adhesion strength after being placed in a high humidity environment. Further, in the liquid crystal sealing agent of the present invention, the constituent components have little elution of the liquid crystal, and the display failure of the liquid crystal display unit can be reduced. Moreover, since it is excellent in storage stability, it is suitable for manufacture of a liquid crystal display unit. Further, the liquid crystal display unit produced by using the liquid crystal sealing agent of the present invention has sufficient characteristics such as high voltage holding ratio and low ion density as a liquid crystal display unit.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the invention is not limited to the examples. In addition, the "parts" and "%" described herein are based on quality unless otherwise stated.

[Synthesis Example 1] [Synthesis of epoxy acrylate of bisphenol A epoxy resin]

282.5 g of bisphenol A type epoxy resin (product name: YD-8125, manufactured by Nippon Steel Chemical Co., Ltd.) was dissolved in 266.8 g of toluene, and 0.2 g of dibutylhydroxytoluene was added thereto as a polymerization inhibitor. Up to 60 ° C. Then, 117.5 g of 100% equivalent of acrylic acid of epoxy group was added, and the temperature was further raised to 80 ° C, and 0.2 g of trimethylammonium chloride as a reaction catalyst was added thereto, and the mixture was stirred at 98 ° C for about 30 hours to obtain a reaction liquid. By washing the reaction liquid and distilling off Benzene obtained 540 g of a bisphenol A type epoxy acrylate as a target.

[Synthesis Example 2] [Synthesis of Epoxy Methacrylate of Bisphenol A Type Epoxy Resin]

282.5 g of bisphenol A type epoxy resin (product name: YD-8125, manufactured by Nippon Steel Chemical Co., Ltd.) was dissolved in 266.8 g of toluene, and 0.2 g of dibutylhydroxytoluene was added thereto as a polymerization inhibitor. Up to 60 ° C. Then, 141.1 g of methacrylic acid having 100% equivalent of an epoxy group was added, and the temperature was further raised to 80 ° C, and 0.2 g of a reaction catalyst, that is, trimethylammonium chloride was added thereto, and the mixture was stirred at 98 ° C for about 30 hours to obtain a reaction liquid. . The reaction liquid was washed with water, and toluene was distilled off to obtain 540 g of a desired bisphenol A type epoxy methacrylate.

[Synthesis Example 3] [Synthesis of epoxy acrylate of resorcinol diglycidyl ether]

181.2 g of resorcinol diglycidyl ether (manufactured by Nagase ChemteX Co., Ltd.) was dissolved in 266.8 g of toluene, and 0.8 g of dibutylhydroxytoluene was added thereto as a polymerization inhibitor, and the temperature was raised to 60 °C. Then, 117.5 g of 100% equivalent of acrylic acid of epoxy group was added, and the temperature was further raised to 80 ° C, and 0.6 g of trimethylammonium chloride as a reaction catalyst was added thereto, and the mixture was stirred at 98 ° C for about 30 hours to obtain a reaction liquid. The reaction liquid was washed with water, and toluene was distilled off to obtain 293 g of an epoxy acrylate as the intended meta- benzenediol diglycidyl ether.

[Examples 1-3, Comparative Examples 1-2]

The ratio shown in the following Table 1 is acrylated in the component (a) (meth) Heating the dissolved component in the epoxy resin (b) photopolymerization initiator, component (f) epoxy resin, component (h) having a phenolic hydroxyl group, and cooling to room temperature, adding component (c) inorganic filler The component (d) organic hydrazine compound, component (e) thermal radical polymerization initiator, and component (g) decane coupling agent were uniformly mixed by a three-roll mill. Next, the liquid crystal sealing agents of Examples 1 to 3 were prepared by filtration through a metal mesh. Further, the materials shown in Table 1 were mixed in the same manner to prepare liquid crystal sealing agents of Comparative Examples 1 and 2.

[Measurement of Adhesion Strength of ITO (Indium Tin Oxide) Substrate]

1 g of a glass fiber (PF-50S: manufactured by Nippon Electric Glass Co., Ltd.) of 5 μm was added as a spacer to 100 g of the obtained liquid crystal sealing agent, and the mixture was stirred and mixed. This liquid crystal sealing agent was applied onto a 50 mm × 50 mm ITO (Indium Tin Oxide) substrate (470 × 370 × 0.7 SP30 ITO: manufactured by GEOMATEC Co., Ltd.), and a glass piece of 1.5 mm × 1.5 mm was attached to the liquid crystal sealing agent. (The EAGLE XG: manufactured by CORNING Co., Ltd. was cut into 1.5 mm squares), and the shear adhesion strength was measured under the conditions of A [MPa], B [MPa], C [MPa], and D [MPa]. The results are shown in Table 1.

[Adhesion strength to organic film]

The alignment film solution (PIA-5540-05A; manufactured by CHISSO Co., Ltd.) was applied to a glass substrate by a spin coater, and the plate was preheated at 60 ° C for 90 seconds, and baked at 220 ° C for 1 hour. The glass substrate with the oriented film was cut into two types of 25 mm × 25 mm and 25 mm × 30 mm, and washed with an ultraviolet ozone cleaning device (UVD-25U03: manufactured by Nippon UV Machine Co., Ltd.) for 80 seconds. After ultraviolet ozone treatment, a 25 mm × 25 mm glass substrate with an orientation film was applied, and a liquid crystal sealing agent was applied by a dispenser or a screen printing machine, and a 25 mm × 30 mm glass substrate with an orientation film was attached thereto, and irradiated with a UV irradiation machine at 3000 mJ/ After ultraviolet light of cm ² , it was placed in an oven and heat-hardened at 120 ° C for 1 hour. For the obtained test piece, the adhesion strength was measured by an adhesion strength tester (SS-30WD: Xijin Commercial Co., Ltd.) with the stylus pressed against the straight line distance of 2 mm from the sealed end. The results are shown in Table 1.

1 synthesized according to Synthesis Example 1

2 synthesized according to Synthesis Example 2

3 synthesized according to Synthesis Example 3

4 Synthesized according to the method described in International Publication No. 2006/027982

5SS-15 (made by Osaka Chemical Industry Co., Ltd.)

6SPC (C.I. Chemical Co., Ltd.)

7IXE-100 (East Asia Synthetic Co., Ltd.)

8D-600 (made by Japan Talc Co., Ltd.)

9SDH (made by Japan FINECHEM Co., Ltd.)

10 Synthesized by the method described in International Publication No. 2011/06190

11YD-8125 (manufactured by Nippon Steel Chemical Co., Ltd.)

12KBM-603 (Shin-Etsu Chemical Industry Co., Ltd.)

13Sila-Ace S-510 (manufactured by CHISSO Co., Ltd.)

14PN-152 (manufactured by Nippon Kayaku Co., Ltd.)

15Paraloid EXL-2655 (manufactured by Rohm and Haas)

16PET-30 (made by Nippon Kayaku Co., Ltd.)

According to the results of Table 1, it was confirmed that the liquid crystal sealing agents of Examples 1 to 3 had a very strong adhesion to the oriented film, that is, to the organic film. Therefore, the liquid crystal sealing agent of the present invention can realize a liquid crystal display unit excellent in reliability even in the design of a liquid crystal display unit which is applied to an alignment film.

[Industry Utilization]

The liquid crystal sealing agent of the present invention is excellent in adhesion to an organic film such as an oriented film, and is not easily peeled off even in various environments. Therefore, a liquid crystal display unit that can be used in a wide variety of environments can be realized. Further, since the general characteristics such as low liquid crystal contamination, heat resistance, heat cycle resistance, and moisture resistance are also excellent, a liquid crystal display unit excellent in long-term reliability can be realized.

Claims (13)

A liquid crystal sealing agent for liquid crystal dropping method, which is cured by irradiating ultraviolet rays of 3000 mJ/cm ² and cured at 120 ° C for 1 hour, and then curing the cured liquid crystal sealing agent at 25 ° C for ITO (indium tin oxide) The adhesion strength of the substrate is A [MPa], and the adhesion strength of the liquid crystal sealing agent after curing at 120 ° C is B [MPa], and the liquid crystal sealing is performed by curing only ultraviolet rays of 3000 mJ/cm ² . When the adhesive strength of the ITO (indium tin oxide) substrate is C [MPa] at 25 ° C, the above A, B, and C satisfy the relationship represented by the following formulas (1) and (2): B ≧ 0.5 ×A (1) C≧0.3×A (2). The liquid crystal sealing agent for liquid crystal dropping method according to claim 1, wherein the liquid crystal sealing agent which has been cured by ultraviolet rays of only 3000 mJ/cm ² has an adhesion strength to an ITO (indium tin oxide) substrate at 120 ° C. In the case of D [MPa], the above A and D satisfy the relationship represented by the following formula (3): D ≧ 0.3 × A (3). The liquid crystal sealing agent for liquid crystal dropping method according to claim 1, which comprises: component (a) (meth) acrylated epoxy resin, component (b) photopolymerization initiator, component (c) inorganic filler, And component (d) an organic hydrazine compound. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 3, further comprising a component (e) a thermal radical polymerization initiator. The liquid crystal sealing agent for liquid crystal dropping method according to claim 4, wherein the component (e) thermal radical polymerization initiator is 1,2-bis(trimethyldecyloxy) -1,1,2,2-tetraphenylethane. The liquid crystal sealing agent for liquid crystal dropping method according to claim 3, further comprising a component (f) epoxy resin. The liquid crystal sealing agent for liquid crystal dropping method according to claim 3, further comprising a component (g) decane coupling agent. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 7, wherein the component (g) decane coupling agent is an amino decane coupling agent. The liquid crystal sealing agent for liquid crystal dropping method according to claim 7, wherein the component (g) decane coupling agent is a mixture of an amino decane coupling agent and an epoxy decane coupling agent. The liquid crystal sealing agent for a liquid crystal dropping method according to claim 3, further comprising a compound having a phenolic hydroxyl group as component (h). The liquid crystal sealing agent for a liquid crystal dropping method according to claim 10, wherein the compound having a phenolic hydroxyl group in the component (h) is a phenolic phenol resin. A liquid crystal display unit manufacturing method for liquid crystal sealing agent for liquid crystal dropping method according to any one of claims 1 to 11, wherein a liquid crystal display unit comprising two substrates is formed in one of the substrates. After the liquid crystal is dropped on the inside of the crucible, the other substrate is bonded, and then the liquid crystal sealing agent for liquid crystal dropping method is cured by ultraviolet rays and/or heat. A liquid crystal display unit obtained by curing a liquid crystal sealing agent for a liquid crystal dropping method according to any one of claims 1 to 11, which is obtained by curing a liquid crystal sealing agent according to any one of claims 1 to 11.