WO2011061910A1

WO2011061910A1 - Novel thermal radical generator, method for producing the same, liquid crystal sealing agent, and liquid crystal display cell

Info

Publication number: WO2011061910A1
Application number: PCT/JP2010/006651
Authority: WO
Inventors: 昌典橋本; 常俊坂野; 直美荷見; 真規恵曽根
Original assignee: 日本化薬株式会社
Priority date: 2009-11-17
Filing date: 2010-11-12
Publication date: 2011-05-26
Also published as: TWI482777B; JP5783606B2; CN102612521B; JPWO2011061910A1; CN104031082A; KR101806152B1; CN102612521A; TW201129574A; TW201437220A; TWI511974B; KR20120085855A

Abstract

Provided are a tetraphenylethane derivative represented by general formula (1), a method for producing the same, the use of the tetraphenylethane derivative as a radical generator, a liquid crystal sealing agent containing the tetraphenylethane derivative, and a thermosetting liquid crystal sealing agent for the one-drop fill process in particular. The radical generator does not foam and has excellent thermal radical generating performance, and, when used with a liquid crystal sealing agent, the resulting liquid crystal sealing agent does not contaminate liquid crystals, has a long pot life, and performs well in terms of forming a seal and forming a cell gap. (1) Y¹ and Y² in general formula (1) are each independently a hydrogen atom, phenyl, or silicon atom, R¹through R⁶ are each independently a hydrogen atom or C_1-4 linear or branched alkyl group, and X¹ through X⁴ are each independently a hydrogen atom, methyl group, ethyl group, methoxy group, ethoxy group, phenoxy group, or halogen group. R¹through R³ or R⁴ through R⁶ that bond with Y¹ or Y², respectively, are not present when Y¹ or Y² is a hydrogen atom, and Y¹ and Y² are not both hydrogen atoms.

Description

Novel thermal radical generator, method for producing the same, liquid crystal sealing agent, and liquid crystal display cell

The present invention relates to a novel silylbenzopinacol, its use as a thermal radical generator, a liquid crystal sealing agent containing the same, and a liquid crystal display cell using the same.

Conventionally, azo compounds, organic peroxides, benzoins, benzoin ethers, acetophenones, benzopinacols, etc. are known as radical generators for curing radically polymerizable compounds by radical polymerization by heating. in use.

Azo compounds and organic peroxides, which are most likely to generate radicals by thermal cleavage, are used as radical generators in products such as adhesives, sealants, gap forming agents and molding materials. However, since the radical generator is accompanied by the generation of a gas such as nitrogen or carbon dioxide when the radical is generated, there is a concern that the characteristics of the product may be greatly impaired by the gas. For example, the characteristics that may be damaged include a decrease in adhesive strength, a decrease in heat resistance strength, a shape defect of a molded product, and the like. Other radical generators include benzoins, benzoin ethers, acetophenones, benzopinacols, and the like. In these, foaming at the time of heating is small, but radical generation ability is inferior, and there is a problem that desired performance (reactivity and curability) cannot be obtained.

Patent Document 1 discloses that benzopinacol is used as a thermal radical generator in a system that is cured using both ultraviolet rays and heat in order to cure a shadow portion that is not exposed to light. Patent Document 2 discloses that an iniferter type radical generator is effective in producing molded products such as contact lenses, various lenses, and dental materials, and benzopinacol is mentioned as an example. Further, Patent Document 3 mentions benzopinacol as a thermal radical generator used in a sealant for flat panel displays.

Patent Documents

1 and 3 further mention compounds in which benzopinacol is chemically modified. The compounds are further described as exhibiting the desired effect. However, benzopinacol is a tertiary alcohol, and no suitable one has been reported for obtaining a stable derivative having a poor hydroxyl group due to the steric hindrance of the phenyl group.

In addition, as one of the fields of use of the thermal radical generator, there is a liquid crystal sealing agent for a liquid crystal display cell.
With the increase in size of liquid crystal display cells, in recent years, a liquid crystal dripping method has been introduced as a method of manufacturing liquid crystal display cells, which is more mass-productive than conventional liquid crystal vacuum injection liquid crystal display cell manufacturing methods. Has been manufactured (see Patent Document 4). The liquid crystal dropping method is to apply a liquid crystal sealing agent weir on the liquid crystal substrate (main seal), and then apply the sealing agent to the outermost circumference, apply the sealing agent (dummy seal), drop the liquid crystal inside the internal seal, and then This is a manufacturing method in which the liquid crystal display cell is completed by bonding the other liquid crystal substrate facing each other in a vacuum, sealing the liquid crystal by releasing it to atmospheric pressure, and curing the seal portion by UV irradiation and heating. . As a liquid crystal sealing material used for sealing liquid crystal in this manufacturing method, not a conventional thermosetting liquid crystal sealing agent but a photothermosetting combined type liquid crystal sealing agent is generally used. The reason why a conventional thermosetting liquid crystal sealant (also called a thermosetting liquid crystal sealant) is not used in the liquid crystal dropping method is that when the liquid crystal dropping method is performed with the conventional thermosetting liquid crystal sealing agent, heating is performed under vacuum and reduced pressure. This is because the thermal expansion of the liquid crystal during heating and the viscosity decrease due to the heating of the liquid crystal sealant occur, the seal punctures and the liquid crystal cannot be sealed.

The photo-curing combined type liquid crystal sealant is used by applying a liquid crystal sealant weir to the liquid crystal substrate with a dispenser, etc., then dropping the liquid crystal inside the weir and attaching the other substrate facing in vacuum. After the alignment, the liquid crystal cell is manufactured by irradiating the seal portion with light such as ultraviolet rays and temporarily curing, and then thermally curing the liquid crystal sealant at about 120 ° C. for about 1 hour.

However, in the case of the photothermographic combination type, the liquid crystal sealant must be irradiated with light such as ultraviolet rays. However, the following problems occur with the narrowing of the frame of the liquid crystal cell in recent years.
That is, the liquid crystal seal portion is shielded from light by the wiring or the black matrix, and a portion where the liquid crystal sealant is not irradiated with light is formed, so that an uncured portion is generated. There has been a problem that the uncured portion is inserted by the liquid crystal during the heat curing process or liquid crystal contamination occurs. Therefore, in designing the liquid crystal cell, there has been a restriction that the sealant must be designed so that as much light as possible is irradiated. Further, since deterioration of the liquid crystal and the alignment film due to ultraviolet irradiation becomes a problem, it is necessary to shield the liquid crystal portion with a light shielding mask during the ultraviolet irradiation process so that the ultraviolet rays do not hit the liquid crystal. Furthermore, along with the increase in the size of the liquid crystal glass substrate, the ultraviolet irradiation apparatus is increased in size, and the running cost of the ultraviolet irradiation apparatus is increasing.

From the above, in recent years, in the liquid crystal dropping method, a thermosetting liquid crystal sealing agent (thermosetting liquid crystal sealing agent for liquid crystal dropping method) that does not require ultraviolet irradiation and can produce a liquid crystal display cell only by thermosetting Realization is desired.
To date, proposals have been made for thermosetting liquid crystal sealing agents for the liquid crystal dropping method. For example, in

Patent Document

5, 3 to 40 thermosetting agents are added to 100 parts by weight of a curable resin having a value obtained by dividing the number of hydrogen bonding functional groups in one molecule by molecular weight of 3.5 × 10 ⁻⁴ or more. A thermosetting liquid crystal sealing agent for liquid crystal dropping method containing parts by weight has been proposed. It has been disclosed that the use of this liquid crystal sealant results in low liquid crystal contamination. However, in the liquid crystal dropping method using the thermosetting liquid crystal sealing agent, there is a problem that the liquid crystal leaks because the weir of the liquid crystal sealing agent in the middle of curing, whose viscosity has been lowered by heating, is broken (seal puncture problem) In addition, the liquid crystal sealant component whose viscosity has been reduced by heating is heated more than the NI point (temperature at which the isotropic phase transitions to the liquid crystal phase) or more, so that the liquid crystal becomes more fluid than usual. It is difficult to say that the serious problem of leaching out and contaminating the liquid crystal has been sufficiently solved.

Further, in Patent Document 6, the liquid crystal sealant to which the gelling agent is added can prevent the seal puncture and keep the seal shape by the liquid crystal dropping method only by thermosetting. However, it has not been solved about the contamination of the liquid crystal sealant to the liquid crystal at the time of heat curing, which is a problem of the thermosetting liquid crystal dropping method.
Patent Document 7 proposes a manufacturing method in which a liquid crystal sealant made of a thermosetting resin is applied, pre-baked, and thereafter liquid crystal dropping and vacuum bonding are performed. However, the specific resin composition of the liquid crystal sealant is not specified.

Patent Documents

8 and 9 propose a thermosetting liquid crystal sealing method for a liquid crystal dropping method in which a pre-baking process is performed as a B-stage (semi-cured state) process. Since this method requires a B-stage treatment for 20 minutes at 80 ° C., there is a drawback that the process time becomes long. Further, if the processing temperature is increased to, for example, 100 ° C. or higher in order to shorten the B-stage processing time for 20 minutes, the described liquid crystal sealant is not preferable because the curing reaction proceeds.
Patent Document 7 proposes a liquid crystal sealing agent characterized by containing a thermal cleavage type radical generator, a thermosetting compound containing a compound having an unsaturated double bond, and a polyaddition type thermosetting agent. Yes. And, there is described production of a liquid crystal display element that is partially UV-irradiated by bonding a liquid crystal substrate at atmospheric pressure. However, there is no description about the production of a liquid crystal display element only by thermosetting without UV irradiation by vacuum decompression bonding of a liquid crystal substrate.
As mentioned above, there is no thermosetting liquid crystal dropping sealant that solves all the problems with the thermosetting sealant in the liquid crystal dropping method, and the liquid crystal dropping method only by thermosetting has not been realized yet.

In addition, in recent years, there has been a strong demand to increase the display area without increasing the external size of the substrate. For this reason, liquid crystal cells have been designed such as narrowing the outer periphery of the liquid crystal seal and narrowing the liquid crystal seal width. As a result, there has been a demand for a liquid crystal sealant that can be formed with a narrow seal width and has a uniform seal shape that is not easily disturbed, and a liquid crystal sealant that has high adhesive strength even if the seal width is narrow. Further, there is a demand for a liquid crystal sealant having a long pot life in which the change in the application condition of the liquid crystal sealant is small within the working time.
In recent years, with the spread of liquid crystal televisions and the like, the cell gap of the liquid crystal (the gap between the two substrates filled with liquid crystal) is narrowed in order to increase the high-speed response of the liquid crystal when playing back moving images. It is coming. There has been a demand for a liquid crystal sealant that can easily narrow the cell gap when the liquid crystal substrate is vacuum-bonded.

And in response to the demand for a long life of the liquid crystal cell, deterioration of the liquid crystal seal under high humidity conditions has become a problem. There has been a demand for a liquid crystal sealant with a small deterioration of the adhesive strength of the liquid crystal seal after the high temperature and high humidity test.
As described above, the thermosetting type liquid crystal dropping method is realized, the substrate is vacuum-bonded, does not seal puncture by heating, and there is no liquid crystal contamination, and the adhesive strength after the moisture resistance test is strong. There is a need for a thermosetting liquid crystal sealant for liquid crystal dropping method that has excellent seal coatability, has a long pot life at room temperature, and is easy to narrow the cell gap.

JP-A-57-53508 Japanese Patent Laid-Open No. 11-21304 JP 2006-10870 A Japanese Patent Publication No. 8-20627 Japanese Patent No. 3955038 Japanese Patent No. 3976749 JP 2005-92043 A JP 2007-199710 A JP 2007-224117 A

The present invention has been made in view of the above-described background art, and a first object of the present invention is to develop a novel thermal radical generator that does not foam during heating and has a higher activity.
A second object of the present invention is to provide a thermosetting liquid crystal sealing agent for a liquid crystal dropping method which does not require ultraviolet irradiation. Furthermore, thermosetting liquid crystal seal for liquid crystal dripping method with low liquid crystal contamination, high adhesive strength and high adhesive strength after moisture resistance test, excellent seal linearity, long pot life at room temperature, and easy narrowing of cell gap The present invention provides an agent (hereinafter also referred to as a thermosetting liquid crystal sealing agent for a liquid crystal dropping method).

As a result of intensive studies to solve the above-mentioned problems, the present inventors have made at least one hydroxyl group of benzopinacol optionally having a substituent on the benzene ring into a foam during heating. In addition, it has been found that a more highly active novel thermal radical generator can be obtained, and that the thermosetting liquid crystal sealing agent for liquid crystal dropping method can be obtained by using the thermal radical generator. The invention has been completed.
That is, the present invention relates to the following (1) to (20).

(1) The following general formula (1 ')

(Wherein Y ¹ ′ and Y ² ′ each independently represent a hydrogen atom or a silicon atom, and R ¹ to R ⁶ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms) X ¹ to X ⁴ each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen group, provided that they are bonded to Y ¹ ′ or Y ² ′, respectively. to ^R 1 ~ ^{R 3,} or ^R 4 ~ ^{R 6} is not present if ^{Y 1} 'or ^{Y 2'} is a hydrogen atom, and unless ^{Y 1} 'and ^{Y 2'} is a hydrogen atom, further, ^{Y 1} A tetraphenylethane derivative represented by the formula: “and Y ² ′ are silicon atoms, all of R ¹ to R ⁶ are methyl groups, and all of X ¹ to X ⁴ are hydrogen atoms”.
(2) In the general formula (1 ′), one of Y ¹ ′ and Y ² ′ is a hydrogen atom and the other is a silicon atom, and in the case of a silicon atom, R ¹ R ² R ³ Y ¹ ′ — R ⁴ R ⁵ R ⁶ Y ² ′ — is a di (C 1-4 straight or branched alkyl) silyl group or a tri (C ^1-4 straight or branched alkyl) silyl group, and X ¹ The tetraphenylethane derivative according to the above (1), wherein all of .about.X ⁴ are hydrogen atoms.
(3) In the general formula (1 ′), one of Y ¹ ′ and Y ² ′ is a hydrogen atom and the other is a silicon atom, and in the case of a silicon atom, R ¹ R ² R ³ Y ¹ ′ — R ⁴ R ⁵ R ⁶ Y ² '-is trimethylsilyl, triethylsilyl, or t-butyldimethylsilyl, and all of X ¹ to X ⁴ are hydrogen atoms, and the tetraphenyl according to (1) or (2) above Ethane derivative.
(4) Following formula (2)

The tetraphenylethane derivative according to any one of the above (1) to (3), which is 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane represented by the formula:

(5) (a) The following general formula (1)

Wherein Y ¹ or Y ² each independently represents a hydrogen atom, phenyl or silicon atom, and R ¹ to R ⁶ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. X ¹ to X ⁴ each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen atom, provided that R is bonded to Y ¹ or Y ² , respectively. ¹ to R ³ or R ⁴ to R ⁶ are not present when Y ¹ or Y ² is a hydrogen atom, and each of Y ¹ and Y ² is a hydrogen atom. A liquid crystal dropping method comprising a derivative, (b) one or both of an epoxy resin or an epoxy resin (meth) acrylic acid adduct, (c) a thermosetting agent, and (d) an inorganic filler. Thermosetting liquid crystal sealant.
(6) (a) The tetraphenylethane derivative of the general formula (1) is the tetraphenylethane derivative according to any one of the above (1) to (4) or the following (20), Liquid crystal sealant.
(7) The liquid crystal sealing agent according to the above (5) or (6), wherein the tetraphenylethane derivative of the general formula (1) is a solid powder having an average particle size of 5 μm or less.
(8) (c) The liquid crystal sealant according to any one of the above (5) to (7), which is a latent curing agent having a melting point or softening point of 100 ° C. or higher.
(9) The liquid crystal sealing agent according to any one of (5) to (8), wherein (d) the inorganic filler is alumina and / or silica.
(10) The liquid crystal sealing agent according to any one of (5) to (9), wherein (d) the inorganic filler has an average particle size of 10 to 2000 nm.
(11) The liquid crystal sealant as described in any one of (5) to (10) above, which comprises (e) a curing accelerator.
(12) The liquid crystal sealing agent according to any one of (5) to (11) above, which contains a coupling agent (f).
(13) (a) 0.1 to 10% by mass of the tetraphenylethane derivative of the general formula (1) with respect to the total amount of the liquid crystal sealant, (b) (meth) acrylic acid of epoxy resin and / or epoxy resin The adduct is 30 to 75% by mass with respect to the total amount of the liquid crystal sealant, (c) the thermosetting agent is 5 to 60 parts by mass with respect to 100 parts by mass of the component (b), and (d) the inorganic filler. The liquid crystal sealant according to any one of the above (5) to (12), which is contained in a range of 1 to 30% by mass with respect to the total amount of the liquid crystal sealant.
(14) (a) In the general formula (1), when either Y ¹ or Y ² is a hydrogen atom and the other is a silicon atom, R ¹ R ² R ³ Y ¹ — or R ⁴ R ⁵ R ⁶ Y ² — represents a di (linear or branched alkyl having 1 to 4 carbon atoms) silyl group or a tri (linear or branched alkyl having 1 to 4 carbon atoms) silyl group, and X ¹ to X ^A tetraphenylethane derivative in which all ⁴ are hydrogen atoms, (b) one or both of an epoxy resin and an (meth) acrylic acid adduct of an epoxy resin, or (c) a melting point or a softening point of 100 as a thermosetting agent. (5) to (5) above, which contains a latent curing agent having a temperature of not lower than ° C., (d) an inorganic filler, and (e) a curing accelerator or (f) a coupling agent. 13) Liquid crystal sealing agent as described in any one of

(15) A liquid crystal display cell sealed with a cured product of the liquid crystal sealant according to any one of (5) to (14) above.
(16) A radical generator containing the tetraphenylethane derivative of the general formula (1) described in (5) as an active ingredient.
(17) Use of the tetraphenylethane derivative of the general formula (1) described in the above (5) as the radical generator described in the above (16) for producing a thermosetting liquid crystal sealant.
(18) A cured product obtained by thermally curing a radical curable resin composition containing the tetraphenylethane derivative of the general formula (1) described in (5) above.
(19) The following general formula (3)

(Wherein X ¹ to X ⁴ each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen group)
The following formula (1 ′) for reacting a benzopinacol represented by the formula:

(Wherein Y ¹ ′ and Y ² ′ each independently represent a hydrogen atom or a silicon atom, and R ¹ to R ⁶ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms) X ¹ to X ⁴ each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen group, provided that they are bonded to Y ¹ ′ or Y ² ′, respectively. R ¹ to R ³ or R ⁴ to R ⁶ are not present when Y ¹ ′ or Y ² ′ is a hydrogen atom, and each of Y ¹ ′ and Y ² ′ is a hydrogen atom) The manufacturing method of the tetraphenylethane derivative represented.
(20) In the general formula (1 ′), one of Y ¹ ′ and Y ² ′ is a hydrogen atom and the other is a silicon atom, and in the case of a silicon atom, R ¹ to R ³ or R ⁴ to R ⁶ The tetraphenylethane derivative according to the above (1), wherein each is independently a linear or branched alkyl group having 1 to 4 carbon atoms.

The tetraphenylethane derivative (also referred to as a benzopinacol derivative) represented by the general formula (1) used in the present invention is useful as a thermal radical generator, has no foaming during heating, and can increase the reaction rate. Is possible. Therefore, it can be used as a thermal radical generator that has no fear of deterioration of physical properties due to foaming, for a wide variety of uses such as the production of adhesives, sealants, gap forming agents, molding materials, etc. Products with excellent cured properties, adhesive strength, shape stability, etc. can be obtained. In particular, it is excellent as a thermal radical generator for a thermosetting liquid crystal sealing agent used in a liquid crystal dropping method.
The thermosetting liquid crystal sealing agent using the tetraphenylethane derivative represented by the general formula (1) used in the present invention as a thermal radical generator is for a liquid crystal dropping method that does not require ultraviolet irradiation to the liquid crystal sealing portion. It is optimal as a thermosetting liquid crystal sealant (hereinafter also referred to as the liquid crystal sealant of the present invention). The liquid crystal sealant has excellent properties such as low liquid crystal contamination, high adhesive strength and adhesive strength after moisture resistance test, excellent seal linearity, and long pot life at room temperature. The liquid crystal cell can be easily manufactured. As a result, a high yield, high reliability, and high quality liquid crystal display cell can be manufactured. Further, the liquid crystal display cell of the present invention sealed with a cured product of the liquid crystal sealant of the present invention has no display failure due to liquid crystal contamination, and has excellent adhesion and moisture resistance reliability.
The tetraphenylethane derivative represented by the general formula (1 ′) is a novel compound synthesized by the present inventors.

1 is an NMR (proton) spectrum (solvent: DMSO-d6) of 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane of the present invention.

Hereinafter, the present invention will be described in detail.
In the following description, for the sake of convenience, the general formula (1) will be described. However, except for the case where it does not fall within the range of the general formula (1 ′), the general formula (1) is replaced by the general formula (1). By replacing with “)”, the same applies to the general formula (1 ′). Moreover, even with the description of Y ¹ and Y ^2, replaced respectively with Y ^{1 'and} Y ^2', by excluding those not included in the scope of the Y 1 ^'and Y ^2', is similarly applicable Shall.
In the general formula (1) of the present invention, Y ¹ and Y ² each independently represent a hydrogen atom, a phenyl group or a silicon atom, and at least one of them is a group other than a hydrogen atom. Preferred is when one is a hydrogen atom and the other is a silicon atom.
In the general formula (1) of the present invention, examples of the linear or branched alkyl group having 1 to 4 carbon atoms (hereinafter also simply referred to as C1 to C4 alkyl group) in R ¹ to R ⁶ include, for example, methyl, ethyl, n-propyl , I-propyl, t-butyl and the like. Examples of the halogen in X ¹ to X ⁴ include a fluorine atom, a chlorine atom, and a bromine atom.
When Y ¹ or Y ^{2 in} the general formula (1) is a group other than a hydrogen atom, R ¹ R ² R ³ Y ¹ — or R ⁴ R ⁵ R ⁶ Y ² — represents a phenyl group or 1 to 3 C1 A phenyl group substituted with a -C4 alkyl group, or a di-C1-C4 alkylsilyl group or a tri-C1-C4 alkylsilyl group, more preferably a di-C1-C4 alkylsilyl group or a tri-C1-C4 alkylsilyl group And more preferably a tri-C1 to C4 alkylsilyl group.
In the di- or tri-C 1-4 linear or branched alkylsilyl group in R ¹ R ² R ³ Y ¹ —, R ⁴ R ⁵ R ⁶ Y ² — in the general formula (1), 2 or 3 The alkyl group having 1 to 4 carbon atoms may be the same or different. Examples of the silyl group include di-C1 to C4 alkylsilyl groups such as dimethylsilyl, diethylsilyl, and methylethylsilyl: or trimethylsilyl, triethylsilyl, dimethylethylsilyl And tri-C1 to C4 alkylsilyl groups such as t-butyldimethylsilyl; Of these, a tri-C1 to C4 alkylsilyl group is preferable, and a trimethylsilyl group is more preferable.
X ¹ to X ⁴ each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen group, and preferably all of X ¹ to X ⁴ are hydrogen atoms. Is the case.

Preferred compounds in the tetraphenylethane derivative represented by the general formula (1) include 1-hydroxy-2-di or tri (C1-C4 alkyl) siloxy-1,1,2,2-tetraphenylethane or 1, 2-bis {di or tri (C1-C4 alkyl) siloxy} -1,1,2,2-tetraphenylethane can be mentioned, such as 1-hydroxy-2-di or tri (C1-C4 alkyl) siloxy- 1,1,2,2-tetraphenylethane is more preferable, and 1-hydroxy-2-tri (C1-C4 alkyl) siloxy-1,1,2,2-tetraphenylethane is more preferable.
In di- or tri- (C1-C4 alkyl) siloxy in the above tetraphenylethane, 2 or 3 alkyl groups on the silyl group may be the same or different. For example, tri (C1-C4 alkyl) siloxy includes trimethylsiloxy, triethylsiloxy, t-butyldimethylsiloxy and the like.
Specific examples of preferable tetraphenylethane derivatives include 1,2-bis (trimethylsiloxy) -1,1,2,2-tetraphenylethane and 1,2-bis (triethylsiloxy)- 1,1,2,2-tetraphenylethane, 1,2-bis (t-butyldimethylsiloxy) -1,1,2,2-tetraphenylethane, 1-hydroxy-2-trimethylsiloxy-1,1, 2,2-tetraphenylethane, 1-hydroxy-2-triethylsiloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-t-butyldimethylsiloxy-1,1,2,2-tetra Phenylethane. Preferably 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-triethylsiloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2- t-Butyldimethylsiloxy-1,1,2,2-tetraphenylethane.
Among these, in the present invention, 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane, 1-hydroxy-2-triethylsiloxy-1,1,2,2-tetraphenyl More preferred is ethane or 1-hydroxy-2-t-butyldimethylsiloxy-1,1,2,2-tetraphenylethane, and 1-hydroxy-2-trimethylsiloxy-1,1, represented by the formula (2) 2,2-tetraphenylethane is more preferred.
The tetraphenylethane derivative represented by the general formula (1) of the present invention is characterized by a structure in which the benzopinacol represented by the general formula (3) is silylated with various silylating agents.

The tetraphenylethane derivative represented by the general formula (1) of the present invention is obtained by synthesizing by a method in which the benzopinacol represented by the general formula (3) and various silylating agents are heated under a basic catalyst such as pyridine. be able to.
The silylating agent may be any as long as it can be di-C1-C4 alkylsilylated, tri-C1-C4 alkylsilylated or phenyldi-C1-C4 alkylsilylated, and a tri (C1-C4 alkyl) silylating agent is preferred. . Preferable examples include trimethylchlorosilane (TMCS), hexamethyldisilazane (HMDS), N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA), which are generally known trimethylsilylating agents, and triethylsilylating agent. Examples of chlorosilane (TECS) and t-butyldimethylsilylating agent include t-butyldimethylsilane (TBMS).
These reagents can be easily obtained from markets such as silicon derivative manufacturers. The reaction amount (silylation equivalent) of the silylating agent is preferably 1.0 to 5.0 times equivalent to 1 equivalent of hydroxyl group of benzopinacol represented by the formula (3). More preferably, it is 1.5 to 3.0 times equivalent. If the amount is too small, the reaction efficiency is poor, and the reaction time becomes long, so that thermal decomposition is promoted. On the other hand, when the amount is too large, the separation becomes worse during the recovery or the purification becomes difficult.

Examples of the basic catalyst include pyridine and triethylamine. The basic catalyst has an effect of trapping hydrogen chloride generated during the reaction and keeping the reaction system basic, or drawing out a hydrogen atom of a hydroxyl group to further promote the reaction. The amount used may be 0.5 equivalents or more of the basic group equivalent to 1 equivalent of the hydroxyl group of the target compound, and may be used as a solvent. Usually, the equivalent amount of the basic group of the basic catalyst is 1 to 5 times equivalent to 1 equivalent of the hydroxyl group of the target compound.
As the solvent, nonpolar organic solvents such as hexane, ether and toluene are excellent because they do not participate in the reaction. Also preferred are polar solvents such as pyridine, dimethylformaldehyde (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) and acetonitrile. The amount used is preferably such that the weight concentration of the solute is 5 to 40% by mass. More preferably, it is 10 to 30% by mass. If the amount is too small, the reaction is slow, decomposition by heat is accelerated, and the yield is lowered. Moreover, when there are too many, a by-product will increase and a yield will fall.
When the silyl group is introduced into one of the hydroxyl groups of benzopinacol of the general formula (3), the reaction temperature is preferably 80 ° C. or less, and the reaction time is within 2.5 hours, preferably within 2 hours. The benzopinacol derivative, for example, the benzopinacol of the general formula (3) or the produced target compound is preferably reacted at a low temperature because it causes thermal decomposition by heating. By reacting with time, the target product is obtained in high yield. Considering reaction efficiency, etc., about 50 to 80 ° C. is preferable. The reaction time is about 30 minutes to 2.5 hours, preferably about 30 minutes to 2 hours.
When the silyl group is introduced into both of the hydroxyl groups of the benzopinacol of the general formula (3), a higher temperature, for example, a temperature of about 75 to 100 ° C. is preferable, but the yield is considered to decrease.

The tetraphenylethane derivative represented by the general formula (1) of the present invention can be used as a radical generator. Specifically, it can be used in various fields as a thermal radical generator or a photo radical generator, and is particularly preferably used as a thermal radical generator in the present invention.
The thermal radical generator of the present invention can be used for applications that are difficult to achieve with other photoradical generators. For example, it can be used for curing a portion that is not exposed to light or curing a portion having a problem when irradiated with strong energy. Specifically, as thermal radical generators in sealants for precision equipment, as thermal radical generators for curing areas where low-molecular substances that are subject to decomposition may coexist, and for organic synthesis by thermal reaction, etc. It can be used as a thermal radical generator for Furthermore, since the thermal radical generator of the present invention does not cause foaming when radicals are generated and does not impair the curing rate even with a small amount, it can be expected to maintain the form of the cured product and improve physical properties. In the present invention, the amount of the tetraphenylethane derivative of the general formula (1) used as a radical generator may vary depending on the type of polymerization monomer to be cured and the field of use, and the amount added may be appropriately selected.
One of the preferred fields of use of the thermal radical generator of the present invention is the use as a thermal radical generator in a radical curable resin composition. In this case, the content of the thermal radical generator of the present invention (tetraphenylethane derivative of the general formula (1)) with respect to the total amount of the composition is not particularly limited, but is usually about 0.1 to 10% by mass. The balance is a radically polymerizable resin and additives that may be included as necessary. A cured product of the resin composition can be obtained by thermosetting the resin composition, and the cured product has good transparency because it does not cause turbidity due to foaming, and has adhesiveness, moisture-resistant adhesion, etc. Excellent. In addition, as a radical curable resin, an epoxy resin or a (meth) acrylic resin is mentioned. In particular, as one of useful radical curable resin compositions, a thermosetting sealant can be exemplified, and among them, a thermosetting liquid crystal sealant for a liquid crystal dropping method is optimal.

The thermosetting liquid crystal sealing agent for liquid crystal dropping method of the present invention comprises (a) a tetraphenylethane derivative represented by the general formula (1), (b) an epoxy resin, and / or a (meth) acrylic epoxy resin. An acid adduct, (c) a thermosetting agent, and (d) an inorganic filler are contained as essential components.

The thermosetting liquid crystal sealing agent for liquid crystal dropping method of the present invention contains (a) a tetraphenylethane derivative represented by the general formula (1) as a thermal radical generator in order to improve curability. Hereinafter, the tetraphenylethane derivative represented by the general formula (1) is also referred to as a component (a) or a thermal radical generator (a) for simplification.
In general, a thermal radical generator refers to a compound that dissociates and generates radicals upon heating, and examples thereof include azo compounds, organic peroxides, benzoins, benzoin ethers, acetophenones, and benzopinacols. However, azo compounds and organic peroxides foam when nitrogen and carbon dioxide are generated at the same time when radicals are generated by heating. Therefore, bubbles are included in the cured product, which causes a decrease in cured property and adhesive strength. In addition, benzoin derivatives and benzopinacol do not foam when heated, but the desired curing degree does not occur at the thermal curing temperature of 90 to 130 ° C of the sealant, which is used when manufacturing liquid crystal panels. There was a problem that could not be obtained.

Therefore, as a result of various studies, the present inventors have found that a thermal radical generator with higher activity and less liquid crystal contamination can be obtained by chemical modification to benzopinacol. And it discovered that the benzopinacol derivative in which at least one of the hydroxyl group of pinacol became an ether bond from the ease of a synthesis method was more preferable. Examples of the ether bond include methyl ether, ethyl ether, propyl ether, isopropyl ether, butyl ether, phenyl ether group, silyl ether group, and the like. Among these, a phenyl ether group or a silyl ether group is preferable from the viewpoint of activity and the like, and a tetraphenylethane derivative represented by the general formula (1) is more preferable.

Preferred tetraphenylethane derivatives (a) represented by the general formula (1) used in the present invention include 1-hydroxy-2-di or tri (C1-C4 alkyl) siloxy-1,1, 2,2- Mention may be made of tetraphenylethane or 1, 2-bis {di or tri (C1-C4 alkyl) siloxy} -1,1, 2,2-tetraphenylethane, such as 1-hydroxy-2-di or tri (C1 -C4 alkyl) siloxy-1,1, 2,2-tetraphenylethane is more preferable, and 1-hydroxy-2-tri (C1-C4 alkyl) siloxy-1,1, 2,2-tetraphenyl is more preferable. It is ethane. Specific compound examples are as described above.

It is preferable that the thermal radical generator (a) (tetraphenylethane derivative (a) represented by the general formula (1)) is finely dispersed and uniformly dispersed. The average particle diameter is preferably 5 μm or less, and more preferably 3 μm or less, because if the average particle size is too large, it becomes a cause of defects such as poor gap formation when the upper and lower glass substrates are bonded together during the production of a narrow gap liquid crystal cell. Further, the particle size of the component (a) can be made infinitely fine, but the lower limit is usually about 0.1 μm as the average particle size.

The content of (a) the thermal radical generator in the liquid crystal sealing agent of the present invention is usually 0.1 to 10% by mass, preferably 0.3 to 7% by mass, based on the total amount of the liquid crystal sealing agent. More preferably, it is 0.5 to 5% by mass. When the content is too small, the curability is deteriorated and seal puncture occurs, and when the content is too large, the liquid crystal contamination tends to be strong.
In the present invention, as long as the effect of the present invention is achieved, a radical generator other than the component (a) may be used in combination, but usually the component (a) is used alone as a radical generator. Is preferred.

The epoxy resin and / or (meth) acrylic acid adduct (b) of epoxy resin contained in the thermosetting liquid crystal sealant for the liquid crystal dropping method of the present invention is used as a curable resin. Here, “(meth) acryl” means “acryl” and / or “methacryl”. The epoxy resin and / or the (meth) acrylic acid adduct (b) of the epoxy resin are preferably low in contamination and solubility in the liquid crystal and low in resin viscosity.

The epoxy resin is preferably bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, ethylene oxide-added bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A, for example. Novolac type epoxy resin, bisphenol F novolac type epoxy resin, resorcin diglycidyl ether, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type Epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, phenol novolac type with triphenolmethane skeleton Epoxy resins, diglycidyl ethers of other bifunctional phenols, diglycidyl etherified products such as other difunctional alcohols. These epoxy resins may be used alone or in combination of two or more. Of these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, ethylene oxide-added bisphenol S type epoxy resin, and resorcin diglycidyl ether are more preferable from the viewpoint of liquid crystal contamination and viscosity. preferable.

The (meth) acrylic acid adduct of the epoxy resin (hereinafter also referred to as “(meth) acrylated epoxy resin” for convenience) is a compound obtained by the reaction of an epoxy resin and (meth) acrylic acid, and the epoxy group of the epoxy resin. A compound in which (meth) acrylic acid is added to all or an epoxy group of an epoxy resin is reacted with less than an equivalent amount of (meth) acrylic acid to leave an epoxy group intentionally (hereinafter referred to as partial (meth) acrylated epoxy resin Or any of them).
As the (meth) acrylated epoxy resin, a compound having a bifunctional or higher (meth) acryloyl group is preferable. Further, the ratio of the epoxy group to the (meth) acryloyl group in the partially (meth) acrylated epoxy resin is not limited, and is appropriately selected from the viewpoint of process compatibility and liquid crystal contamination.
In the present invention, (meth) acrylic acid is usually added at a ratio of 50 to 100%, preferably 70 to 100%, more preferably 80 to 100% with respect to all epoxy groups contained in the epoxy resin. A (meth) acrylated epoxy resin is preferred. Usually, (meth) acrylic acid is often used because of its low cost. Therefore, it is preferable to use a compound in which acrylic acid is added to the epoxy group of the epoxy resin.

Although it does not specifically limit as an epoxy resin used as a raw material of this (meth) acrylated epoxy resin, The epoxy resin more than bifunctional is preferable.
For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, ethylene oxide addition bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F Novolac type epoxy resin, resorcin diglycidyl ether, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, dicyclopentadiene type Epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin having triphenolmethane skeleton, other bifunctional phenols Diglycidyl ethers of Le ethers, diglycidyl etherified products such as other difunctional alcohols.
Bisphenol A type epoxy resin, bisphenol F type epoxy resin or resorcin diglycidyl ether is preferable, and resorcin diglycidyl ether is particularly preferable.
Accordingly, the (meth) acrylated epoxy resin can be obtained by the reaction of at least one selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin and resorcin diglycidyl ether with (meth) acrylic acid (meta). ) An acrylated epoxy resin is preferred, and a (meth) acrylated epoxy resin obtained by reaction of resorcin diglycidyl ether and (meth) acrylic acid is more preferred.
As the (meth) acrylated epoxy resin, an acrylated epoxy resin obtained by a reaction between the epoxy resin and acrylic acid is preferable from the viewpoint of curability. More preferably, it is at least one selected from the group consisting of an acrylic acid adduct of bisphenol A type epoxy resin, an acrylic acid adduct of bisphenol F type epoxy resin, and an acrylic acid adduct of resorcin diglycidyl ether.
The above (meth) acrylated epoxy resins may be used alone or in combination of two or more.
In a preferred embodiment, the preferred (meth) acrylated epoxy resin occupies the entire amount of the (meth) acrylated epoxy resin in the liquid crystal sealant.

The content of the epoxy resin and / or (meth) acrylated epoxy resin (b) (hereinafter also simply referred to as curable resin (b)) in the liquid crystal sealant of the present invention is usually relative to the total amount of the liquid crystal sealant. 30 to 75% by mass, preferably 40 to 65% by mass. If the content is too small, the reaction at the time of thermosetting becomes slow, and the weir of the sealing agent becomes sealed due to thermal expansion of the liquid crystal and the lowering of the viscosity of the sealing agent when a liquid crystal cell is produced by the liquid crystal dropping method. If the content is too large, sufficient adhesive strength cannot be obtained.
An embodiment in which both an epoxy resin and a (meth) acrylated epoxy resin are used in combination as the curable resin (b) is one of the preferred embodiments in the sealing agent of the present invention.
In particular, when the epoxy resin and the (meth) acrylated epoxy resin are used in combination, the content of the epoxy resin in the curable resin (b) is usually 3 to 3% relative to the total amount of the curable resin (b). It is 40% by mass, preferably 3 to 30% by mass, more preferably about 5 to 30% by mass, and still more preferably 8 to 30% by mass. In some cases, 5 to 20% by mass is preferable, and 8 to 15% by mass may be more preferable. The balance is (meth) acrylated epoxy resin. Specifically, the content of the (meth) acrylated epoxy is 60 to 97% by mass, preferably 70 to 95% by mass, more preferably 70 to 92% by mass, based on the total amount of the curable resin (b). It is. If the epoxy resin content is too low, the adhesive strength is weakened, and if the epoxy resin content is too high, curing may be delayed and seal puncture may occur easily.

The thermosetting liquid crystal sealing agent for liquid crystal dropping method of the present invention contains a thermosetting agent (c). Any thermosetting agent conventionally used can be used as the thermosetting agent (c), but in the present invention, a latent thermosetting agent (hereinafter also referred to as a latent curing agent) is preferable. A latent curing agent is a compound having a melting point or softening point of a solid at room temperature of 100 ° C. or higher, does not react with a resin component at room temperature, and does not act as a curing agent, but is heated at 100 ° C. or higher, usually 100 to 150. A substance that reacts with a resin component by being gradually dissolved or melted at about 110 ° C., preferably about 110 to 130 ° C., and exhibits a function as a curing agent.
The melting point or softening point in the present invention was measured by thermal analysis using a differential scanning calorimeter (DSC). Specifically, a differential scanning calorimeter (EXSTAR6000 manufactured by Seiko Instruments Inc.) was used, and measurement was performed at a temperature increase of 5 ° C./min.
Examples of the latent curing agent include polyhydrazide compounds, polyamine compounds, imidazole derivatives, urea derivatives, and the like. A polyhydrazide compound is preferred, and a compound having two or more hydrazide groups in the molecule. Di-tetrahydrazide compounds are preferred, and di- or trihydrazide compounds are more preferred.
Examples of the polyhydrazide compound include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecandiodihydrazodihydride, Dihydrazide, fumaric acid dihydrazide, diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4-bisbenzenedihydrazide, 1,4-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,2,4-benzenetrihydrazide, pyromellitic acid tetrahydrazide, 1,4,5,8-naphtho Acid tetrahydrazide; a hydrazide compound having a hydantoin skeleton such as 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydantoin, preferably a valine hydantoin skeleton (a skeleton in which the carbon atom of the hydantoin ring is substituted with an isopropyl group) Tris (1-hydrazinocarbonylmethyl) isocyanurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate, bis (2-hydrazinocarbonylethyl) isocyanurate, etc. Bis or tris (hydrazinocarbonyl C1-C3 alkyl) isocyanurate, and these may be used alone or in combination of two or more. Bis or tris (hydrazinocarbonyl C1-C3 alkyl) isocyanurate is one of the preferred di- or trihydrazide compounds.

Among these polyhydrazide compounds, di- or trihydrazides of di- or tricarboxylic acids are preferred, and more specifically, C4 to C8 aliphatic or aromatic dicarboxylic dihydrazides, excluding carbon of carboxylic acid, or Bis or tris (hydrazinocarbonyl C1-C3 alkyl) isocyanurate and the like. More preferably, it is at least one selected from the group consisting of dihydrazide of C4 to C8 alkylene dicarboxylic acid, dihydrazide of phthalic acid, and tris (hydrazinocarbonyl C1-C3 alkyl) isocyanurate.
Specific examples of preferred polyhydrazides include adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydrantoin, and tris (1-hydrazinocarbonylmethyl) isocyanate. Examples thereof include nurate, tris (2-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate, and bis (2-hydrazinocarbonylethyl) isocyanurate.
More preferred are adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, and tris (2-hydrazinocarbonylethyl) isocyanurate.

The thermosetting agent (c) is preferably dispersed uniformly with a fine particle size in order to make it a rapid curing latent curing agent. If the average particle size is too large, it becomes a cause of defects such as inability to form a gap when the upper and lower glass substrates are bonded together when manufacturing a narrow gap liquid crystal cell. Therefore, the particle size is preferably 4 μm or less, more preferably 3 μm or less. The particle size was measured with a laser diffraction / scattering type particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd .: LMS-30). In addition, since it will become easy to raise | generate aggregation if an average particle diameter is too small, it is preferable to prepare so that it may not become extremely small (for example, 0.1 micrometer or less).

In the liquid crystal sealing agent of the present invention, the content of the thermosetting agent (c) is usually 5 parts by mass to 100 parts by mass of the curable resin (b) which is an epoxy resin and / or a (meth) acrylated epoxy resin. The amount is about 60 parts by mass, preferably 10 to 40 parts by mass. When there are few thermosetting agents (c) than 5 mass parts, thermosetting reaction will become inadequate and adhesive force and a glass transition point will become low. On the other hand, when there are more thermosetting agents (c) than 60 mass parts, a hardening | curing agent will remain, adhesive force will fall, and pot life will also deteriorate.

The thermosetting liquid crystal sealant for the liquid crystal dropping method of the present invention contains an inorganic filler (d). Examples of the inorganic filler (d) include alumina, silica (such as spherical silica or fumed silica), talc, clay, bentonite, organic bentonite, barium titanate, titanium oxide, cobalt oxide, magnesium oxide, nickel oxide, and zirconium oxide. Metal oxides such as calcium carbonate and magnesium carbonate, sulfates such as barium sulfate and calcium sulfate, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, calcium silicate, aluminum silicate, silicic acid Examples thereof include silicates such as zirconium. These may be used alone or in combination of two or more. Of these inorganic fillers, alumina and / or silica are particularly preferable.

The average particle diameter of the inorganic filler (d) is preferably 3 μm or less.
If the average particle size is too large, it will hinder the gap formation when the upper and lower glass substrates are bonded together during the production of the liquid crystal cell. The lower limit of the average particle size of the inorganic filler (d) is usually about 0.01 μm.
The content of the inorganic filler (d) in the liquid crystal sealing agent of the present invention is usually 1 to 30% by mass, preferably 2 to 20% by mass, more preferably 3 to 15% by mass. When there is too little content, the adhesive strength with respect to a glass substrate will fall. Moreover, when there is too much filler content, a viscosity will be too high and applicability | paintability will worsen.

The liquid crystal sealant of the present invention contains a curing accelerator (e) in order to accelerate the curability of the thermosetting reaction.
The curing accelerator (e) is not particularly limited as long as it has a high thermosetting reaction accelerating property during heating, low contamination to liquid crystals, and does not deteriorate the pot life of the liquid crystal sealant during normal temperature storage.
Examples thereof include polyvalent carboxylic acids having an isocyanuric ring skeleton, epoxy resin amine adducts, imidazole derivatives, urea derivatives, and the like. These may be used alone or in combination of two or more. Preferred examples of the curing accelerator include urea compound curing accelerators and isocyanuric ring skeleton-containing polycarboxylic acid curing accelerators. Specifically, aliphatic dimethylurea (trade name: UCAT3503N manufactured by Sun Apro Co., Ltd.) (a compound in which a methyl group and two dimethylurea groups are substituted on the cyclohexane ring), aromatic dimethylurea (trade name) : UCAT3502T manufactured by San Apro Co., Ltd. (a compound in which two dimethylurea groups are substituted at the 2- and 3-positions of toluene) and tris (carboxy C1-C3 alkyl) isocyanurate. Examples of tris (carboxy C1-C3 alkyl) isocyanurate include tris (1-carboxymethyl) isocyanurate, tris (2-carboxyethyl) isocyanurate, tris (3-carboxypropyl) isocyanurate, bis (2-carboxyethyl). ) Isocyanurate. Of these, tris (3-carboxypropyl) isocyanurate is preferable.

It is preferable that the curing accelerator (e) is uniformly dispersed with a fine particle size so as to be a rapid curing latent curing accelerator. If the average particle size is too large, it becomes a cause of defects such as inability to form a gap when the upper and lower glass substrates are bonded together when manufacturing a narrow gap liquid crystal cell. Therefore, the average particle size is preferably 4 μm or less, more preferably 3 μm or less. The lower limit as the average particle size is usually about 0.1 μm.

The content of the curing accelerator (e) in the liquid crystal sealant of the present invention is preferably 0.5 to 15% by mass, more preferably 1 to 8% by mass, based on the total amount of the liquid crystal seal.
If the content is too small, the curability is deteriorated and seal puncture occurs, and if the content is too large, the room temperature storage stability and the linearity of the seal are deteriorated.

A coupling agent (f) may be added to the liquid crystal sealant of the present invention in order to improve the adhesive strength. There is no particular limitation on the coupling agent (f).
Examples of the coupling agent (f) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy) (Cyclohexyl) ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane , 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltri Methoxysilane, 3- Silane coupling agents such as rolopropylmethyldimethoxysilane and 3-chloropropyltrimethoxysilane; isopropyl (N-ethylaminoethylamino) titanate, isopropyl triisostearoyl titanate, titanium di (dioctyl pyrophosphate) oxyacetate, tetraisopropyl di Titanium coupling agents such as (dioctyl phosphite) titanate and neoalkoxytri (pN- (β-aminoethyl) aminophenyl) titanate; Zr-acetylacetonate, Zr-methacrylate, Zr-propionate, neoalkoxyzirco , Neoalkoxy tris neodecanoyl zirconate, neoalkoxy tris (dodecanoyl) benzenesulfonyl zirconate, neoalkoxy tris (ethylene di) Minoethyl) zirconate, neoalkoxytris (m-aminophenyl) zirconate, zirconium-based coupling agents such as ammonium zirconium carbonate; aluminum-based coupling agents such as Al-acetylacetonate, Al-methacrylate, Al-propionate; These may be used alone or in admixture of two or more.
Of these coupling agents, a silane coupling agent is preferable, and an aminosilane coupling agent or an epoxy silane coupling agent is more preferable.
By using the coupling agent, it is possible to obtain a liquid crystal sealing agent having excellent moisture resistance reliability and little decrease in adhesive strength after moisture absorption. When the coupling agent is contained in the liquid crystal sealing agent of the present invention, the content thereof is about 0.05 to 3% by mass.

The liquid crystal sealant of the present invention may contain a polythiol compound (g) for further improving curability. The polythiol compound is preferably a compound having two or more thiol groups in the molecule, such as methanedithiol, 1,2-dimercaptoethane, 1,2-dimercaptopropane, 2,2-dimercaptopropane, , 3-dimercaptopropane, 1,2,3-trimercaptopropane, 1,4-dimercaptobutane, 1,6-dimercaptohexane, bis (2-mercaptoethyl) sulfide, 1,2-bis (2- Mercaptoethylthio) ethane, 1,5-dimercapto-3-oxapentane, 1,8-dimercapto-3,6-dioxaoctane, 2,2-dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane -1,2-dithiol, 2-mercaptomethyl-1,3-dimercaptopropane, 2-mercaptomethyl-1 4-dimercaptobutane, 2- (2-mercaptoethylthio) -1,3-dimercaptopropane, 1,2-bis (2-mercaptoethylthio) -3-mercaptopropane, 1,1,1-tris ( Mercaptomethyl) propane, tetrakis (mercaptomethyl) methane, ethylene glycol bis (2-mercaptoacetate), ethylene glycol bis (3-mercaptopropionate), 1,4-butanediol bis (2-mercaptoacetate), 1, 4-butanediol bis (3-mercaptopropionate), trimethylolpropane tris (2-mercaptoacetate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol Trakis (3-mercaptopropionate), 1,1-dimercaptocyclohexane, 1,4-dimercaptocyclohexane, 1,3-dimercaptocyclohexane, 1,2-dimercaptocyclohexane, dipentaerythritol hexakis (3- Mercaptopropionate), dipentaerythritol hexakis (2-mercaptoacetate), 1,2-dimercaptobenzene, 1,3-dimercapto-2-propanol, 2,3-dimercapto-1-propanol, 1,2- Dimercapto-1,3-butanediol, hydroxymethyl-tris (mercaptoethylthiomethyl) methane, hydroxyethylthiomethyltris (mercaptoethylthio) methane, ethylene glycol bis (3-mercaptopropionate), propylene group Recall bis (3-mercaptopropionate), butanediol bis (3-mercaptopropionate), octanediol bis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate), ethylene glycol Bis (4-mercaptobutyrate), propylene glycol bis (4-mercaptobutyrate), butanediol bis (4-mercaptobutyrate), octanediol bis (4-mercaptobutyrate), trimethylolpropane tris (4-mercapto) Butyrate), pentaerythritol tetrakis (4-mercaptobutyrate), ethylene glycol bis (6-mercaptovalerate), propylene glycol bis (6-mercaptovalerate), butanediol bis (6- Luccaptovalerate), octanediol bis (6-mercaptovalerate), trimethylolpropane tris (6-mercaptovalerate), pentaerythritol tetrakis (6-mercaptovalerate), 1,6-hexanedithiol, 1,9 -Nonanedithiol, 1,10-decanedithiol, 4,4'-bis (mercaptomethyl) phenyl sulfide, 2,4'-bis (mercaptomethyl) phenyl sulfide, 2,4,4'-tri (mercaptomethyl) phenyl Sulfide, 2,2 ′, 4,4′-tetra (mercaptomethyl) phenyl sulfide, 1,3,5-tris [2- (3-mercaptopropionyloxy) ethyl] -1,3,5-triazine-2, 4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (3- Lucaptobutyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis (3-mercapto Butyryloxy) butane and the like. These may be used alone or in combination of two or more.

Among these polythiol compounds, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), 1, 3, 5-tris [2- (3-mercaptopropionyloxy) ethyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (3-mercapto (Butyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate) are preferred, and liquid crystal contamination and room temperature are more preferred. From the viewpoint of storage stability, 1,3,5-tris (3-merca having a secondary thiol structure DOO butyl oxy) -1,3,5-triazine-2,4,6 (IH, 3H, 5H) - trione, pentaerythritol tetrakis (3-mercapto butyrate) is particularly preferred.

When the polythiol compound (g) is contained in the thermosetting liquid crystal sealing agent for liquid crystal dropping method of the present invention, the content thereof is usually 0.1 to 10% by mass, preferably 0.3 to 5% by mass. . If the content is too small, the curability is poor and seal puncture is likely to occur, and if the content is too large, the room temperature storage stability tends to be poor.

The organic filler (h) may be added to the thermosetting liquid crystal sealant for the liquid crystal dropping method of the present invention within a range that does not affect the properties of the liquid crystal sealant. Examples of the organic filler (h) include silicone rubber fine particles, acrylic rubber fine particles, and core-shell type acrylic fine particles. These organic fillers may be used alone or in combination of two or more.

The average particle diameter of the organic filler that may be added is usually 5 μm or less, preferably 2 μm or less. When the average particle size is too large, it becomes difficult to form a cell gap. However, when the organic filler is a silicone rubber powder, a cell gap can be formed even if the average particle size is large. Therefore, the preferable average particle size of the silicone rubber powder is 15 μm or less.
In addition, when the organic filler is contained in the liquid crystal sealing agent of the present invention, the content thereof is preferably 40% by mass or less, and more preferably 30% by mass or less with respect to the total amount of the liquid crystal sealing agent. The lower limit may be 0% by mass. Usually, it is preferably 1% by mass or more, more preferably 5% by mass or more. When the amount is too large, the viscosity becomes high and it becomes difficult to form a cell gap. The aspect which contains this organic filler in the liquid-crystal sealing compound of this invention is one of the preferable aspects.
In addition, an aspect in which silicone rubber fine particles and other organic fillers such as (meth) acrylic resin fine particles, preferably core-shell type (meth) acrylic fine particles are used in combination as the organic filler is also one of the preferable embodiments of the present invention. . In that case, it is preferable to use the silicone rubber fine particles in a proportion of usually 1 to 10 parts by mass, preferably 3 to 7 parts by mass with respect to 1 part by mass of the other organic filler.

If necessary, the liquid crystal sealing agent of the present invention may further contain additives such as a photo radical polymerization initiator, an organic solvent, a pigment, a leveling agent, and an antifoaming agent.
Next, some preferred embodiments for the sealant of the present invention will be described.
1. In the invention described in any one of (5) to (14) described in the above “Means for Solving the Problems”, the curable resin (b) is an epoxy resin and a (meth) acrylated epoxy resin. The aspect which is combined use.
2. 2. The embodiment according to 1 above, wherein the content of the epoxy resin is 3 to 40% by mass and the content of the (meth) acrylated epoxy resin is 60 to 97% by mass with respect to the total amount of the curable resin (b).
3. In the above 1 or 2, in the case of the embodiment containing the curing accelerator (e) (the invention described in (11) to (14) of (5) to (14) in the above 1), the content of the curing accelerator Is 0.5 to 15% by mass, preferably 1 to 8% by mass, based on the total amount of the sealing agent of the present invention.
4). 4. The aspect according to 3 above, wherein the curing accelerator (e) is an isocyanuric ring skeleton-containing polyvalent carboxylic acid curing accelerator.
5. 5. The embodiment according to 4 above, wherein the curing accelerator (e) is tris (carboxy C1-C3 alkyl) isocyanurate.
6). In the case of the embodiment (the invention described in (12) to (14) of (5) to (14) in 1) including the coupling agent (f) described in any one of 1 to 5 above The embodiment according to any one of 1 to 5 above, wherein the content of the coupling agent (f) is 0.05 to 3% by mass relative to the total amount of the sealing agent of the present invention.
7). The aspect of said 6 whose coupling agent (f) is a silane coupling agent.
8). The embodiment according to any one of the above 1 to 7, further comprising 0.1 to 10% by mass of the polythiol compound (g) based on the total amount of the sealing agent of the present invention.
9. The embodiment according to any one of 1 to 8 above, further comprising the organic filler (h) in a range of 1 to 40% by mass with respect to the total amount of the sealing agent of the present invention.

In order to obtain the liquid crystal sealing agent of the present invention, the above-mentioned epoxy resin and / or (meth) acrylated epoxy resin (b) and, if necessary, a coupling agent or additive are dissolved and mixed, and the above-mentioned heat is added thereto. Adding a curing agent (c), the thermal radical generator (a), the inorganic filler (d), the curing accelerator (e) and other optional components as appropriate, a normal mixing device, for example, What is necessary is just to mix uniformly by a 3 roll, a sand mill, a ball mill, etc. It is preferable to perform a filtration treatment to remove foreign substances after mixing is completed.

In the liquid crystal display cell of the present invention, a pair of substrates on which predetermined electrodes are formed are arranged to face each other at a predetermined interval, the periphery is sealed with the liquid crystal sealant of the present invention, and the liquid crystal is sealed in the gap. The kind of liquid crystal to be sealed is not particularly limited.
Here, the substrate is made of glass, quartz, plastic, silicon or the like. In the method for producing a liquid crystal display cell by the thermosetting liquid crystal dropping method, first, a spacer (gap control material) such as glass fiber is added to and mixed with the liquid crystal sealing agent of the present invention. Examples of the spacer include glass fiber, silica beads, polymer beads and the like. The diameter varies depending on the purpose, but is usually 2 to 8 μm, preferably 3 to 6 μm, and the amount used is usually 0.1 to 4 parts by weight, preferably 0.5 to 4 parts per 100 parts by weight of the liquid crystal sealant. The amount is about 2 parts by mass, more preferably about 0.9 to 1.5 parts by mass.

After applying a liquid crystal sealant containing a spacer to one side of the substrate with a dispenser or the like to form a weir (main seal), in order to keep the liquid crystal sealing substrate in a vacuum, the sealant is further applied to the outermost circumference. Apply (dummy seal). Thereafter, the liquid crystal is dropped inside the weir of the internal seal, and the other glass substrate is overlaid in a vacuum, and then opened to the atmospheric pressure to release the gap. The dummy sealant for holding the liquid crystal sealing substrate in a vacuum does not come into contact with the liquid crystal and is cut off after completion of the liquid crystal cell. Even if the same liquid crystal sealant is used, another UV curable type is used. A sealant, a visible light curable sealant, or a thermosetting sealant may be used. After the vacuum gap is formed, when UV curable sealant or visible light curable sealant, which is a light curable sealant, is used for the dummy seal, UV or visible light is applied to the dummy seal part by an ultraviolet irradiator or visible light irradiator. Irradiate to cure the dummy seal. If no photo-curing sealant is used for the dummy seal, the light irradiation step is omitted. The substrate with the gap formed is heated at 90 to 130 ° C. for 1 to 2 hours, and then the dummy seal portion is cut off, whereby the liquid crystal display cell of the present invention can be obtained.
The liquid crystal display cell of the present invention thus obtained has no display defects due to liquid crystal contamination, and has excellent adhesion and moisture resistance reliability.

Hereinafter, the present invention will be described in more detail with reference to examples.
In addition, this invention is not limited at all by the following examples.
Moreover, unless otherwise indicated in an Example, a part means a mass part and% means the mass%.

Example A
[Synthesis of 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane] (silylated benzopinacol)
100 parts (0.28 mol) of commercially available benzopinacol (manufactured by Tokyo Chemical Industry) was dissolved in 350 parts of dimethylformaldehyde. To this was added 32 parts (0.4 mol) of pyridine as a base catalyst and 150 parts (0.58 mol) of BSTFA (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silylating agent, and the mixture was heated to 70 ° C. and stirred for 2 hours. The obtained reaction solution was cooled and stirred while adding 200 parts of water to precipitate the product and deactivate the unreacted silylating agent. The precipitated product was separated by filtration and thoroughly washed with water. Subsequently, the obtained product was dissolved in acetone, recrystallized by adding water and purified. 105.6 parts (yield: 88.3%) of the target 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane were obtained.
As a result of analysis by HPLC (high performance liquid chromatography), the purity was 99.0% (area percentage).
438 molecular ion peaks were obtained by HPLC-MASS (high performance liquid chromatography mass spectrometry). Further, as a chemical shift value from the NMR spectrum (solvent DMSO-d6), hydroxyl proton 5.8 ppm (1H), siloxymethyl proton 0.0 ppm (9H), phenyl proton 7.1 ppm (16H), 7.4 ppm (4H) Obtained and identified as the desired product. The NMR spectrum is shown in FIG.

It should be noted that the benzopinacol derivative is considered to have selectively introduced a silyl group on one side in the above reaction because the reactivity of the other hydroxyl group further decreases due to a large steric hindrance when one of the two tertiary alcohols reacts.

Experimental example 1
In order to see the effect of the thermal radical generator of the present invention, the gelation time at 120 ° C. of the sample (the time for curing on a 120 ° C. hot plate) and a foaming test were performed.
(Test method)
For 10 parts of acrylic acid adduct of bisphenol A type epoxy resin (manufactured by Nippon Kayaku Co., Ltd .: R93100), in Test Example 1 (the present invention) as a thermal radical generator, 1-hydroxy-2-trimethylsiloxy of the present invention is used. -1,1,2,2-tetraphenylethane, benzopinacol in Test Example 2 (for comparison), t-butylperoxy-2-ethylhexanoate in Test Example 3 (for comparison) (manufactured by Kayaku Akzo Corporation) : Kaya ester O) mixed in 0.1 part each was kneaded with three rolls to prepare each sample.
The obtained sample was placed on a 120 ° C. hot plate and cured (gelation time at 120 ° C.) and the presence or absence of turbidity due to foaming of the cured product was visually observed. The results are shown in Table A. The curing time was measured by bringing a glass rod into contact with the sample and measuring the time until the sample stopped pulling the yarn.

The evaluation criteria for turbidity due to foaming are as follows.
Evaluation of presence or absence of turbidity due to foaming ○: The cured product is transparent without turbidity due to foaming.
(Triangle | delta): Hardened | cured material is slightly cloudy by foaming and transparency is also falling a little.
X: White turbidity due to foaming is clearly observed in the entire cured product, and the transparency is also clearly lowered.

Table A
Test Example 1 Test Example 2 Test Example 3
Gel time 7sec 23sec 4sec
Turbidity ○ ○ ×

As shown in Table A, the thermal radical generator of the present invention (Test Example 1) has a high curing rate, no foaming, and no turbidity, so that it can be applied to various applications that require transparency. .
On the other hand, in Test Example 2 to be compared, there is no problem with transparency, but the curing time is long and there is a problem with workability. Although Test Example 3 is excellent in terms of the curing time, turbidity due to foaming occurs, so it is transparent. Since the properties are inferior, it is unsuitable for uses requiring transparency, and there is a concern that the physical properties of the cured product may be reduced due to foaming.

Examples 1 and 2 and Comparative Examples 1 and 2
A resin liquid was obtained by mixing an acrylated epoxy resin, an epoxy resin, and a silane coupling agent described in Table 1 below.
Table 1 shows the inorganic filler, thermosetting agent, curing accelerator, silylated benzopinacol, polythiol compound, silicone rubber powder (organic filler) and core-shell acrylic fine particles (organic filler) in the obtained resin liquid. The liquid crystal sealants of Examples 1 and 2 were obtained by blending with the three blending amounts and kneading with three rolls.
In the composition of Example 1, a liquid crystal sealant of Comparative Example 1 was obtained in the same manner as in Example 1 except that benzopinacol was used in the amount shown in Table 1 instead of silylated benzopinacol.
Further, in the composition of Example 1, a liquid crystal sealant of Comparative Example 2 was obtained in the same manner as in Example 1 except that organic peroxide was used in the amount shown in Table 1 instead of silylated benzopinacol. It was.

Reference Synthesis Example 1 [Synthesis of All Acrylate of Resorcin Diglycidyl Ether]
140 parts of resorcin diglycidyl ether resin was dissolved in 160 parts of toluene. To this, 0.48 part of dibutylhydroxytoluene was added as a polymerization inhibitor, and the temperature was raised to 60 ° C. Thereafter, 100 parts of acrylic acid (100% equivalent of the epoxy group of resorcin diglycidyl ether resin) was added, and the temperature was further raised to 80 ° C., and 0.96 part of trimethylammonium chloride as a reaction catalyst was added thereto. Stir at 50 ° C. for about 50 hours. The obtained reaction solution was washed with water and toluene was distilled off to obtain 241 parts of an epoxy acrylate of resorcinol.

Table 1
Example 1 Example 2 Comparative Example 1 Comparative Example 2
Acrylic epoxy resin * 1 16 16 16 16
Epoxy resin * 2 4 4 4 4
Inorganic filler * 3 1.25 1.25 1.25 1.25
Silicone rubber powder * 4 9 9 9 9
Silane coupling agent * 5 0.3 0.3 0.3 0.3
Silane coupling agent * 6 0.05 0.05 0.05 0.05
Thermosetting agent * 7 2.8 2.8 2.8 2.8
Silylated benzopinacol * 8 0.5 0.5--
Benzopinacol * 9--0.5-
Organic peroxide * 10---0.5
Polythiol compound * 11 0.2 0.2 0.2 0.2
Curing accelerator * 12 1 0.5 1 1
Acrylic fine particles * 13 2 2 2 2

The numerical values in Table 1 are parts by weight.
* 1: Total acrylate of resorcin diglycidyl ether (compound obtained in Reference Synthesis Example 1)
* 2: Resorcin diglycidyl ether (manufactured by Nippon Kayaku Co., Ltd., trade name: RGE-HH)
* 3: Spherical silica (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-24-9163A; primary average particle size 110 nm)
* 4: Silicone rubber powder (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KMP-598; primary average particle size 13 μm)
* 5: 3-Glycidoxypropyltrimethoxysilane (manufactured by Chisso Corporation, trade name: Silaace ^RTM S-510)
* 6: N-2 (aminoethyl) 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM603)
* 7: Tris (2-hydrazinocarbonylethyl) isocyanurate finely pulverized product (manufactured by Nippon Finechem Co., Ltd., trade name: HCIC finely pulverized with jet mill to an average particle size of 1.5 μm)
* 8: 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane (compound obtained in the same manner as in Example A (silylated benzopinacol) was averaged in a diameter of 1.9 μm using a jet mill. Finely ground)
* 9: Finely pulverized benzopinacol (Benzopinacol manufactured by Tokyo Chemical Industry Co., Ltd., pulverized to an average particle size of 1.9 μm with a jet mill)
* 10: t-Butylperoxy-2-ethylhexanoate (manufactured by Kayaku Akzo Co., Ltd., trade name: Kayaester ^RTM O)
* 11: Pentaerythritol tetrakis (3-mercaptobutyrate) (manufactured by Showa Denko KK, trade name: Karenz ^RTM MT PE1)
* 12: Tris (3-carboxypropyl) isocyanurate pulverized product (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: C3-CIC acid finely pulverized with a jet mill to an average particle size of 1.5 μm)
* 13: Core-shell acrylic fine particles (manufactured by Ganz Kasei Co., Ltd., trade name: F351S; average particle size 0.3 μm)

Preparation of liquid crystal cell for evaluation 1 g of 5 μm glass fiber is added as a spacer to 100 g of each of the liquid crystal sealants of Examples 1 and 2 or Comparative Examples 1 and 2, and the mixture is stirred and degassed and filled into a syringe. An alignment film solution (trade name: PIA-5540-05A, manufactured by Chisso Corporation) was applied to a glass substrate with an ITO transparent electrode, fired, and rubbed. Using this dispenser (SHOTMASTER 300: manufactured by Musashi Engineering Co., Ltd.), the liquid crystal sealant of Example and Comparative Example previously filled in the syringe on this substrate was applied with a seal pattern and a dummy seal pattern. : JC-5015LA, manufactured by Chisso Corporation) was dropped into the frame of the seal pattern. Furthermore, an in-plane spacer (trade name: NATCO SPACER KSEB-525F, manufactured by NATCO, gap width of 5 μm after bonding) is sprayed on another glass substrate that has been rubbed, heat-fixed, and a vacuum bonding apparatus is used. Then, it was bonded to the previous liquid crystal dripped substrate in a vacuum. Then, after opening to the atmosphere and forming a gap, it was put into an oven at 120 ° C. and cured by heating for 1 hour to prepare a liquid crystal test cell for evaluation.

Table 2 shows the results of observing the seal shape and liquid crystal alignment disorder of the prepared liquid crystal cell for evaluation with a polarizing microscope. Further, Table 2 shows the results of measuring the gap of the prepared liquid crystal cell using a liquid crystal characteristic evaluation apparatus (trade name: OMS-NK3, manufactured by Chuo Seiki Co., Ltd.). Evaluation of the seal shape, liquid crystal alignment disorder, and the gap of the liquid crystal cell was made into the following four stages.

Evaluation of seal shape ○: There is no disturbance in the linearity of the seal.
[Delta]: Deformation of the seal is recognized, but there is no problem in sealing the liquid crystal.
X: A level at which liquid crystal is inserted into the seal and a problem may occur in sealing the liquid crystal.
XX: The seal is broken and a cell cannot be formed.

Evaluation of liquid crystal cell gap ○: The inside of the cell is uniformly 5 μm.
Δ: There is a cell gap of about 5.5 μm in the cell.
X: There is a place where a cell gap of 6 μm or more exists in the cell.
XX: The seal is broken and a cell cannot be formed.

Evaluation of liquid crystal alignment (circle): There is no disorder of liquid crystal alignment in the vicinity of the seal.
(Triangle | delta): There exists orientation disorder in the area | region slightly in the seal | sticker vicinity.
X: There is orientation disorder from the vicinity of the seal to a wide area.
XX: The seal is broken and a cell cannot be formed.

Table 2
Example 1 Example 2 Comparative Example 1 Comparative Example 2
Seal shape ○ ○ ○ ××
Liquid crystal cell gap ○ ○ ○ ××
Liquid crystal alignment ○ △ × ××

Liquid Crystal Sealant Adhesive Strength Test 1 g of 5 μm glass fiber as a spacer is added to 100 g of each liquid crystal sealant of Examples 1 and 2 or Comparative Examples 1 and 2 and mixed and stirred. This liquid crystal sealant was applied onto a 50 mm × 50 mm glass substrate, a 1.5 mm × 1.5 mm glass piece was bonded onto the liquid crystal sealant, and cured by placing in a 120 ° C. oven for 1 hour. The shear adhesive strength of the glass piece was measured using a bond tester (trade name: SS-30WD, manufactured by Seishin Shoji Co., Ltd.). The results are shown in Table 3 below.

Liquid crystal sealant moisture-resistant adhesive strength test The same measurement sample as the liquid crystal sealant adhesive strength test is prepared. The test sample was placed in a pressure cooker tester (trade name: TPC-411, manufactured by Tabai Espec Co., Ltd.) for 20 hours under the conditions of 121 ° C., 2 atm, and humidity 100%, and a bond tester (trade name: SS- 30WD: manufactured by Seishin Shoji Co., Ltd.). The results are shown in Table 3 below.

Using a pot life R-type viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity change at 25 ° C. of the obtained liquid crystal sealant was measured. The viscosity increase rate (%) with respect to the initial viscosity is shown in Table 3 below.

Table 3
Example 1 Example 2 Comparative Example 1 Comparative Example 2
Initial viscosity Pa · s (25 ° C.) 185 165 180 150
Pot life (vs. initial viscosity increase)
1 day after storage at 25 ° C 3% 3% 3% 8%
Adhesive strength (MPa) 78 62 58 38
Adhesive strength after moisture resistance (MPa) 58 45 40 15

As shown in Tables 2 and 3, the liquid crystal sealant of the example of the present invention using silylated benzopinacol as a radical generator is compared with the liquid crystal sealant of Comparative Example 1 using benzopinacol as a radical generator. In terms of liquid crystal alignment, adhesive strength, and post-humidity adhesive strength, all are remarkably excellent.

From the above, the tetraphenylethane derivative of the present invention is useful as a thermal radical generator having a short gel time and no foaming in the radical curable resin composition because it has high radical generation performance due to heat and no foaming. In addition, since there is no decrease in transparency due to foaming or a decrease in physical properties of other cured products, a resin cured product having high transparency and good physical properties can be obtained. In addition, when the tetraphenylethane derivative is used as a thermal radical generator in a liquid crystal sealant, the sealant has little liquid crystal contamination, a long pot life, seal formation, and cell gap formation. Since it is good, the workability is also good, and furthermore, it has the characteristics that both the adhesive strength and the adhesive strength after moisture resistance are excellent. Therefore, it is particularly suitable as a thermosetting liquid crystal sealing agent for a liquid crystal dropping method.

Claims

The following general formula (1 ')

(Wherein Y 1 ′ and Y 2 ′ each independently represent a hydrogen atom or a silicon atom, and R 1 to R 6 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms) X 1 to X 4 each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen group, provided that they are bonded to Y 1 ′ or Y 2 ′, respectively. to R 1 ~ R 3, or R 4 ~ R 6 is not present if Y 1 'or Y 2' is a hydrogen atom, and unless Y 1 'and Y 2' is a hydrogen atom, further, Y 1 A tetraphenylethane derivative represented by the formula: “and Y 2 ′ are silicon atoms, all of R 1 to R 6 are methyl groups, and all of X 1 to X 4 are hydrogen atoms”.
In the general formula (1 ′), one of Y 1 ′ and Y 2 ′ is a hydrogen atom and the other is a silicon atom, and in the case of a silicon atom, R 1 R 2 R 3 Y 1 ′ — or R 4 R 5 R 6 Y 2 ′ — represents a di (C 1-4 straight or branched alkyl) silyl group or a tri (C 1-4 straight or branched alkyl) silyl group, and X 1 to X 4 Any of these is a hydrogen atom, The tetraphenylethane derivative of Claim 1.
In the general formula (1), either Y 1 ′ or Y 2 ′ is a hydrogen atom and the other is a silicon atom, and in the case of a silicon atom, R 1 R 2 R 3 Y 1 ′ — or R 4 R 5 The tetraphenylethane derivative according to claim 1, wherein R 6 Y 2 '-is trimethylsilyl, triethylsilyl or t-butyldimethylsilyl, and any of X 1 to X 4 is a hydrogen atom.
Following formula (2)

The tetraphenylethane derivative according to claim 1, which is 1-hydroxy-2-trimethylsiloxy-1,1,2,2-tetraphenylethane represented by the formula:
(A) The following general formula (1)

Wherein Y 1 or Y 2 each independently represents a hydrogen atom, phenyl or silicon atom, and R 1 to R 6 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. X 1 to X 4 each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen atom, provided that R is bonded to Y 1 or Y 2 , respectively. 1 to R 3 or R 4 to R 6 are not present when Y 1 or Y 2 is a hydrogen atom, and each of Y 1 and Y 2 is a hydrogen atom. A liquid crystal dropping method comprising a derivative, (b) one or both of an epoxy resin or an epoxy resin (meth) acrylic acid adduct, (c) a thermosetting agent, and (d) an inorganic filler. Thermosetting liquid crystal sealant.
(A) The liquid crystal sealant according to claim 5, wherein the tetraphenylethane derivative of the general formula (1) is the tetraphenylethane derivative according to any one of claims 1 to 4.
(A) The liquid crystal sealant according to claim 5, wherein the tetraphenylethane derivative of the general formula (1) is a solid powder having an average particle size of 5 μm or less.
(C) The liquid crystal sealant according to claim 5, which is a latent curing agent having a melting point or a softening point of 100 ° C or higher.
(D) The liquid crystal sealant according to claim 5, wherein the inorganic filler is alumina and / or silica.
(D) The liquid crystal sealant according to claim 5, wherein the inorganic filler has an average particle size of 10 to 2000 nm.
(E) The liquid crystal sealant according to claim 5, further comprising a curing accelerator.
(F) A liquid crystal sealing agent according to claim 5, which contains a coupling agent.
(A) A tetraphenylethane derivative of the general formula (1) is 0.1 to 10% by mass with respect to the total amount of the liquid crystal sealant, and (b) an epoxy resin and / or a (meth) acrylic acid adduct of the epoxy resin. 30 to 75% by mass with respect to the total amount of the liquid crystal sealing agent, (c) 5 to 60 parts by mass of the thermosetting agent with respect to 100 parts by mass of the component (b), and (d) an inorganic filler, The liquid crystal sealant according to claim 5, which is contained in the range of 1 to 30% by mass with respect to the total amount of the sealant.
(A) In the general formula (1), when either Y 1 or Y 2 is a hydrogen atom and the other is a silicon atom and is a silicon atom, R 1 R 2 R 3 Y 1 — or R 4 R 5 R 6 Y 2 — is a di (C 1-4 straight or branched alkyl) silyl group or a tri (C 1-4 straight or branched alkyl) silyl group, and any of X 1 to X 4 A tetraphenylethane derivative which is a hydrogen atom, (b) either one or both of an epoxy resin or an (meth) acrylic acid adduct of an epoxy resin, and (c) a melting point or softening point of 100 ° C. or more as a thermosetting agent. 6. A liquid crystal sealant according to claim 5, comprising a latent curing agent, (d) an inorganic filler, and (e) a curing accelerator or (f) a coupling agent or both. .
A liquid crystal display cell sealed with a cured product of the liquid crystal sealant according to claim 5.
A radical generator containing the tetraphenylethane derivative of the general formula (1) described in claim 5 as an active ingredient.
Use of the tetraphenylethane derivative of the general formula (1) as a radical generator according to claim 16 for producing a thermosetting liquid crystal sealant.
Hardened | cured material which heat-cured the radical curable resin composition containing the tetraphenylethane derivative of General formula (1) described in Claim 5.
The following general formula (3)

(Wherein X 1 to X 4 each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen group)
The following formula (1 ′) for reacting a benzopinacol represented by the formula:

(Wherein Y 1 ′ and Y 2 ′ each independently represent a hydrogen atom or a silicon atom, and R 1 to R 6 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms) X 1 to X 4 each independently represents a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenoxy group, or a halogen group, provided that they are bonded to Y 1 ′ or Y 2 ′, respectively. R 1 to R 3 or R 4 to R 6 are not present when Y 1 ′ or Y 2 ′ is a hydrogen atom, and each of Y 1 ′ and Y 2 ′ is a hydrogen atom) The manufacturing method of the tetraphenylethane derivative represented.
In the general formula (1 ′), one of Y 1 ′ and Y 2 ′ is a hydrogen atom and the other is a silicon atom, and in the case of a silicon atom, R 1 to R 3 or R 4 to R 6 are each independently The tetraphenylethane derivative according to claim 1, which is a linear or branched alkyl group having 1 to 4 carbon atoms.