JP2005054164A - Photo- and heat-curable resin composition, sealing agent for liquid crystal display element, opening-sealing agent for the liquid crystal display element, vertically-conducting material for the liquid crystal display element, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photo- and heat-curable resin composition excellent in adhesion, when used in production of a liquid crystal device, especially, through a liquid crystal-dropping process, without causing irregularity in cell gaps when cured, to provide a sealing agent for a liquid crystal display element, to provide an opening-sealing agent for the liquid crystal display element, to provide a vertically-conducting material for the liquid crystal display element, and to provide the liquid crystal display device. <P>SOLUTION: This photo- and heat-curable resin composition is used in the liquid crystal-dropping process, contains a reactive resin having a cyclic ether group and a radically-polymerizing functional group in its molecule, and further contains inorganic particles having an average particle diameter of ≤1 μm, wherein the composition has an average linear expansion coefficient (α<SB>1</SB>) of 1×10<SP>-4</SP>to 5×10<SP>-4</SP>/°C in a temperature range from a temperature which is lower than a glass transition temperature of a cured product given by curing the composition with light only by 40°C to a temperature which is lower than the glass transition temperature by 10°C, and further has an average linear expansion coefficient (α<SB>2</SB>) of 2×10<SP>-4</SP>to 1×10<SP>-3</SP>/°C in a temperature range from a temperature which is higher than the glass transition temperature by 10°C to a temperature which is higher than the glass transition temperature by 40°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photothermosetting resin composition, a sealing agent for liquid crystal display elements, a liquid crystal display element sealing agent, and a liquid crystal display element that are excellent in adhesiveness, without causing cell gap unevenness during curing, particularly when used in the production of a liquid crystal display device by a dropping method The present invention relates to a sealing agent for a display element, a vertical conduction material for a liquid crystal display element, and a liquid crystal display device.

Conventionally, a liquid crystal display element such as a liquid crystal display cell is formed by forming a cell by facing two transparent substrates with electrodes facing each other at a predetermined interval and sealing the periphery with a sealing agent. The liquid crystal was injected into the cell from the liquid crystal injection port, and the liquid crystal injection port was sealed using a sealing agent or a sealing agent.
In this method, first, a seal pattern provided with a liquid crystal injection port using a thermosetting sealant is formed on one of two transparent substrates with electrodes by screen printing, and prebaked at 60 to 100 ° C. Dry the solvent in the sealant. Next, alignment is performed with the two substrates facing each other with a spacer interposed therebetween, and the gap in the vicinity of the seal is adjusted by performing hot pressing at 110 to 220 ° C. for 10 to 90 minutes, and then at 110 to 220 ° C. in an oven. Heat for 10 to 120 minutes to fully cure the sealant. Next, liquid crystal was injected from the liquid crystal injection port, and finally, the liquid crystal injection port was sealed using a sealing agent to produce a liquid crystal display element.

  However, according to this manufacturing method, positional displacement, gap variation, and decrease in adhesion between the sealant and the substrate occur due to thermal strain; residual solvent thermally expands to generate bubbles, resulting in gap variation and seal path. The seal curing time is long; the prebaking process is complicated; the usable time of the sealant is short due to the volatilization of the solvent; and it takes time to inject liquid crystal. In particular, in a large liquid crystal display device in recent years, it takes a very long time to inject liquid crystal.

  On the other hand, a manufacturing method of a liquid crystal display element called a dripping method using a photocuring / thermosetting sealant has been studied. In the dropping method, first, a rectangular seal pattern is formed on one of the two transparent substrates with electrodes by screen printing. Next, fine droplets of liquid crystal are dropped and applied to the entire surface of the transparent substrate frame in an uncured state of the sealant, and the other transparent substrate is immediately overlaid, and the seal portion is irradiated with ultraviolet rays for temporary curing. Thereafter, heating is performed at the time of liquid crystal annealing to perform main curing, and a liquid crystal display element is manufactured. If the substrates are bonded together under reduced pressure, a liquid crystal display element can be manufactured with extremely high efficiency. In the future, this dripping method is expected to become the mainstream of liquid crystal display manufacturing methods.

  As a sealing agent used in a conventional construction method, for example, Patent Document 1 discloses an adhesive mainly composed of a partial (meth) acrylate of a bisphenol A type epoxy resin. In addition, similar sealing agents are disclosed in Patent Document 2, Patent Document 3, Patent Document 4, or Patent Document 5, and the like. Patent Document 6 discloses a liquid crystal sealant mainly composed of (meth) acrylate.

  However, even if an attempt is made to produce a liquid crystal display device by a dropping method using these sealing agents, the curability by the initial photocuring is too high, and even if a heat curing step is added, sufficient adhesive strength may not be obtained. There has been a problem that the linear expansion coefficient after photocuring becomes large, resulting in cell gap unevenness due to substrate displacement. In addition, when the curable resin composition similar to that of the sealing agent is used as the vertical conduction material, there is a problem similar to that of the sealing agent.

Japanese Patent Laid-Open No. 6-160872 JP-A-1-243029 JP 7-13173 A Japanese Patent Laid-Open No. 7-13174 Japanese Patent Laid-Open No. 7-13175 Japanese Patent Laid-Open No. 7-13174

  In view of the above-described situation, the present invention is a photothermosetting resin composition, which is excellent in adhesion and does not cause cell gap unevenness during curing, particularly when used in the production of a liquid crystal display device by a dropping method. It is an object to provide a sealing agent for liquid crystal, a sealing agent for liquid crystal display element, a vertical conduction material for liquid crystal display element, and a liquid crystal display device.

The present invention 1 is used in a liquid crystal dropping method, and is a photothermosetting resin composition containing a reactive resin having a cyclic ether group and a radical polymerizable functional group in one molecule and inorganic particles having an average particle diameter of 1 μm or less. The average linear expansion coefficient α ₁ from a temperature 40 ° C. lower than the glass transition temperature of the cured product when cured only by light to a temperature 10 ° C. lower than the glass transition temperature is 1 × 10 ^{−4 to} 5 ×. The average linear expansion coefficient α ₂ from 10 ⁻⁴ / ° C. to a temperature 10 ° C. higher than the glass transition temperature to 40 ° C. higher than the glass transition temperature is 2 × 10 ⁻⁴ to 1 × 10 ⁻³ / ° C. It is a certain photothermosetting resin composition.

The present invention 2 is used in a liquid crystal dropping method, and is a photothermosetting resin composition containing a reactive resin having a cyclic ether group and a radical polymerizable functional group in one molecule and inorganic particles having an average particle diameter of 1 μm or less. The average linear expansion coefficient α ₁ from a temperature 40 ° C. lower than the glass transition temperature of the cured product when cured by light and heat to a temperature 10 ° C. lower than the glass transition temperature is 5 × 10 ⁻⁵ to 1 The average coefficient of linear expansion α ₂ from × 10 ⁻⁴ / ° C. and 10 ° C. higher than the glass transition temperature to 40 ° C. higher than the glass transition temperature is 1 × 10 ^{−4 to} 3 × 10 ⁻⁴ / ° C. This is a photothermosetting resin composition.
The present invention is described in detail below.

  The photothermosetting resin composition of the present invention is used in a liquid crystal dropping method and contains a reactive resin having a cyclic ether group and a radical polymerizable functional group in one molecule. Thereby, the photothermosetting resin composition of the present invention has both photocuring properties and thermosetting properties, and is at least one of a sealing agent, a sealing agent, and a vertical conduction material used for manufacturing a liquid crystal display device by a dropping method. When used as, it can be temporarily cured by heating after being temporarily cured by light irradiation.

Although it does not specifically limit as a cyclic ether group in the said reactive resin, For example, an epoxy group or an oxetane group is suitable.
Moreover, it does not specifically limit as a radically polymerizable functional group in the said reactive resin, For example, a (meth) acryl group is suitable. In addition, in this specification, a (meth) acryl group means an acryl group or a methacryl group.

  The preferable lower limit of the functional group equivalent of the total of the cyclic ether group and the radical polymerizable functional group in the reactive resin is 2.5 mmol / g, and the preferable upper limit is 5.5 mmol / g. When it is less than 2.5 mmol / g, heat resistance and moisture resistance may be inferior, and when it exceeds 5.5 mmol / g, adhesion to a substrate or the like may be insufficient.

  The preferable lower limit of the functional group equivalent of the radical polymerizable functional group in the reactive resin is 2.0 mmol / g, and the preferable upper limit is 5.0 mmol / g. When it is less than 2.0 mmol / g, heat resistance and moisture resistance may be inferior, and when it exceeds 5.0 mmol / g, adhesion to a substrate or the like may be insufficient.

  The preferable lower limit of the value obtained by dividing the equivalent of the radical polymerizable functional group in the reactive resin by the equivalent of the cyclic ether group is 1, and the preferable upper limit is 9. If it is less than 1, the photoreactivity decreases, and even if the sealant is irradiated with light after adjusting the gap, not only the initial temporary curing is lost, but the elution into the liquid crystal may increase, If it exceeds 9, it may be insufficient in terms of adhesion and moisture permeability.

Examples of the reactive resin having a cyclic ether group and a radical polymerizable functional group in one molecule include compounds having at least one epoxy group and (meth) acryl group in one molecule. It is done.
The compound having at least one epoxy group and (meth) acryl group in one molecule is not particularly limited, and examples thereof include (meth) acrylic acid-modified epoxy resins and urethane-modified (meth) acryl epoxy resins. Can be mentioned.

  Examples of the (meth) acrylic acid-modified epoxy resin include, for example, partially (meth) acrylated novolac type epoxy resin, bisphenol type epoxy resin, etc .; biphenyl type epoxy resin, naphthalene type epoxy resin, tris (hydroxyphenyl) alkyl Type epoxy resin, tetrakis (hydroxyphenyl) alkyl type epoxy resin and the like are suitable.

  Examples of the epoxy resin used as a raw material for the (meth) acrylic acid-modified epoxy resin include, for example, a novolak type such as a phenol novolak type, a cresol novolak type, a biphenyl novolak type, a trisphenol novolak type, and a dicyclopentadiene novolak type. Examples of the bisphenol type include bisphenol A type, bisphenol F type, 2,2′-diallyl bisphenol A type, bisphenol S type, hydrogenated bisphenol type, and polyoxypropylene bisphenol A type.

  Among the raw materials of the above (meth) acrylic acid-modified epoxy resin, for example, as a phenol novolak type, Epicron N-740, Epicron N-770, Epicron N-775 (above, Dainippon Ink and Chemicals, Inc.) Manufactured by the company), Epicoat 152, Epicoat 154 (manufactured by Japan Epoxy Resin Co., Ltd.), and examples of the cresol novolak type include Epicron N-660, Epicron N-665, Epicron N-670, Epicron N-673, and Epicron N. -680, Epicron N-695, Epicron N-665-EXP, Epicron N-672-EXP (above, manufactured by Dainippon Ink & Chemicals, Inc.) and the like.

  The partially (meth) acrylated product of the epoxy resin can be obtained, for example, by reacting an epoxy resin and (meth) acrylic acid in the presence of a basic catalyst according to a conventional method. It is possible to obtain an epoxy resin having a desired acrylation rate by appropriately changing the blending amount of the epoxy resin and (meth) acrylic acid.

  The urethane-modified (meth) acrylic epoxy resin is obtained by the following method, for example. That is, a method of reacting a polyol with a bifunctional or higher isocyanate, and further reacting this with a (meth) acrylic monomer having a hydroxyl group and glycidol; (meth) acrylic having a hydroxyl group with a bifunctional or higher isocyanate without using a polyol It can be produced by a method in which a monomer or glycidol is reacted; a method in which glycidol is reacted with a (meth) acrylate having an isocyanate group. Specifically, for example, first, 1 mol of trimethylolpropane and 3 mol of isophorone diisocyanate are reacted under a tin-based catalyst, and an isocyanate group remaining in the obtained compound and hydroxyethyl acrylate which is an acrylic monomer having a hydroxyl group and It can be produced by reacting with glycidol which is an epoxy having a hydroxyl group.

  It does not specifically limit as said polyol, For example, ethylene glycol, glycerol, sorbitol, a trimethylol propane, (poly) propylene glycol etc. are mentioned. The isocyanate is not particularly limited as long as it is bifunctional or higher. For example, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4, 4'-diisocyanate (MDI), hydrogenated MDI, polymeric MDI, 1,5-naphthalene diisocyanate, norbornane diisocyanate, tolidine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate , Tris (isocyanatephenyl) thiophosphate, tetramethylxylene diisocyanate, 1,6,10-undecane triisocyanate, etc. It is below.

  The (meth) acrylic monomer having a hydroxyl group is not particularly limited, and examples of the monomer having one hydroxyl group in the molecule include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. Examples of the monomer having two or more hydroxyl groups in the molecule include epoxy (meth) acrylates such as bisphenol A-modified epoxy (meth) acrylate. These may be used alone or in combination of two or more.

  Further, the reactive resin preferably has a hydroxyl group and / or a urethane bond in terms of reducing compatibility with liquid crystal and eliminating contamination, and in terms of improving heat resistance, a biphenyl skeleton, a naphthalene skeleton, a bisphenol skeleton, It is preferable to have at least one molecular skeleton selected from partial (meth) acrylates of novolac type epoxy resins.

  The reactive resin preferably further has a cyclic structure having 24 or less atoms. Here, the number of atoms means the total number of atoms such as carbon, hydrogen, oxygen, etc. in the molecule constituting the cyclic structure. If the number of atoms exceeds 24, the later-described linear expansion coefficient may not be satisfied or the heat resistance may be inferior.

  The minimum with the preferable equivalent of the cyclic structure in the said reactive resin is 1.5 mmol / g, and a preferable upper limit is 6.0 mmol / g. If it is less than 1.5 mmol / g, the coefficient of linear expansion becomes large and the range described later may not be satisfied. If it exceeds 6.0 mmol / g, the adhesion to the substrate or the like may be insufficient.

The atoms constituting the cyclic structure are not particularly limited, but the skeleton structure is preferably a carbon atom, and such a cyclic structure is preferably aromatic.
The aromaticity is not particularly limited, and examples thereof include benzene, indene, naphthalene, tetralin, anthracene, phenanthrene and the like.

  The preferable lower limit of the number average molecular weight of such a reactive resin is 300, and the preferable upper limit is 550. If it is less than 300, it may elute into the liquid crystal and disturb the alignment of the liquid crystal, and if it exceeds 550, it may be difficult to prepare a sealing agent, a sealing agent or a vertical conduction material due to thickening.

The photothermosetting resin composition of the present invention contains inorganic particles. The said inorganic particle has a role which prevents the hardening shrinkage | contraction of the photothermosetting resin composition of this invention, and achieves the following linear expansion coefficient.
The inorganic particles are not particularly limited, and examples thereof include silica, diatomaceous earth, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, barium sulfate, gypsum, and silicic acid. Examples thereof include calcium, talc, glass beads, sericite activated clay, bentonite, aluminum nitride, silicon nitride and the like. Of these, silica and alumina are preferred.
The shape of the inorganic particles is not particularly limited, and examples thereof include regular shapes such as spherical shapes, needle shapes, and plate shapes, or non-standard shapes.

  The upper limit of the average particle diameter of the inorganic particles is 1 μm. When the thickness exceeds 1 μm, the surface of the cured product obtained by curing the photothermosetting resin composition of the present invention with light and / or heat becomes uneven, resulting in poor cell gap accuracy. A preferred lower limit is 0.01 μm and a preferred upper limit is 0.1 μm. If it is less than 0.01 μm, the thixotropy is increased and aggregates may be generated.

  The inorganic particles are surface-treated with at least one selected from the group consisting of an imidazole silane compound, an epoxy silane compound, and an aminosilane compound having a structure in which an imidazole skeleton and an alkoxysilyl group are bonded via a spacer group. May be. By performing such a surface treatment, the affinity between the inorganic particles and the reactive resin can be increased, and these act as a silane coupling agent to improve the adhesive force and storage stability.

  The photothermosetting resin composition of the present invention preferably further contains a photopolymerization initiator. The photopolymerization initiator is not particularly limited as long as it reacts with a radically polymerizable functional group by light irradiation. Benzophenone, 2,2-diethoxyacetophenone, benzyl, benzoylisopropyl ether, benzyldimethyl ketal, 1- Hydroxy cyclohexyl phenyl ketone, thioxanthone and the like can be mentioned. Use of a compound having a reactive double bond and a photoreaction initiation part is preferable because it can prevent elution of the photopolymerization initiator into the liquid crystal. Of these, benzoin (ether) compounds having a reactive double bond such as a (meth) acryl residue and a hydroxyl group and / or a urethane bond are preferable. The benzoin (ether) compounds represent benzoins and benzoin ethers.

  The minimum with the preferable compounding quantity of the said photoinitiator is 0.1 weight part with respect to 100 weight part of reactive resins, and a preferable upper limit is 10 weight part. If it is less than 0.1 parts by weight, the ability to initiate photopolymerization may be insufficient and the effect may not be obtained. If it exceeds 10 parts by weight, a large amount of unreacted photopolymerization initiator may remain, Weather resistance may deteriorate. A more preferred lower limit is 1 part by weight, and a more preferred upper limit is 5 parts by weight.

The photothermosetting resin composition of the present invention preferably further contains a curing agent. The said hardening | curing agent is for making the cyclic ether group in the said reactive resin react and bridge | crosslink, and has a role which improves the adhesiveness of a hardened | cured material, and moisture resistance.
As the curing agent, a latent curing agent having a melting point of 100 ° C. or higher is preferably used. When a curing agent having a melting point of less than 100 ° C. is used, the storage stability may be remarkably deteriorated. Examples of such a curing agent include hydrazide compounds such as 1,3-bis [hydrazinocarbonoethyl-5-isopropylhydantoin], dicyandiamide, guanidine derivatives, 1-cyanoethyl-2-phenylimidazole, N- [2 -(2-Methyl-1-imidazolyl) ethyl] urea, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, N, N'-bis (2- Methyl-1-imidazolylethyl) urea, N, N ′-(2-methyl-1-imidazolylethyl) -adipamide, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxy Imidazole derivatives such as methylimidazole, modified aliphatic polyamines, tetrahydrophthalic anhydride, ethylene glycol -Acid anhydrides such as bis (anhydrotrimellitate), addition products of various amines and epoxy resins, and the like. Further, as the curing agent, in order to suppress the reactivity of the curing agent, a coating curing agent whose surface is coated may be used. For example, the solid curing agent particle surface is coated with fine particles. Etc.

  A preferable lower limit of the amount of the curing agent is 5 parts by weight with respect to 100 parts by weight of the reactive resin, and a preferable upper limit is 60 parts by weight. If it is out of this range, the adhesiveness and chemical resistance of the cured product will be lowered, and the liquid crystal characteristics may be deteriorated in a high temperature and high humidity operation test. A more preferred lower limit is 10 parts by weight, and a more preferred upper limit is 50 parts by weight.

The photothermosetting resin composition of the present invention preferably further contains a silane coupling agent. The silane coupling agent has a role as an adhesion assistant that improves adhesion to a substrate or the like. Moreover, if it uses for the surface treatment of the said inorganic particle as mentioned above, interaction with the said inorganic particle and the said reactive resin can be improved.
The silane coupling agent is not particularly limited. However, since it is excellent in the effect of improving adhesion to a substrate and the like and can be prevented from flowing into the liquid crystal by chemically bonding with a reactive resin, for example, γ-aminopropyl Trimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-isocyanatopropyltrimethoxysilane, etc., or a structure in which an imidazole skeleton and an alkoxysilyl group are bonded via a spacer group What consists of an imidazole silane compound etc. are used suitably. These silane coupling agents may be used alone or in combination of two or more.

The photothermosetting resin composition of the present invention 1 has an average coefficient of linear expansion α ₁ from a temperature 40 ° C. lower than the glass transition temperature of the cured product when cured only by light to a temperature 10 ° C. lower than the glass transition temperature. × 10 ^-4 a to 5 × 10 ^-4 / ° C., and an average coefficient of linear expansion alpha ₂ from 10 ° C. higher temperature than the glass transition temperature to 40 ° C. higher temperature than the glass transition temperature of 2 × 10 ^-4 to 1 × 10 ^-3 / ° C. When the average linear expansion coefficient α ₁ is less than 1 × 10 ⁻⁴ / ° C. or the average linear expansion coefficient α ₂ is less than 2 × 10 ⁻⁴ / ° C., it is used for manufacturing a liquid crystal display device by a dropping method. When used as a sealing agent, a sealing agent or a vertical conduction material, even if the main curing by heating is performed after the temporary curing by light irradiation, the adhesion to the substrate or the like is insufficient, and sufficient adhesion cannot be obtained. When the average linear expansion coefficient α ₁ exceeds 5 × 10 ⁻⁴ / ° C. or the average linear expansion coefficient α ₂ exceeds 1 × 10 ⁻³ / ° C., the substrate is displaced during temporary curing, and the cell Gap unevenness occurs.

The photothermosetting resin composition of the present invention 2 has an average linear expansion coefficient α ₁ from a temperature 40 ° C. lower than the glass transition temperature of the cured product when cured by light and heat to a temperature 10 ° C. lower than the glass transition temperature. The average linear expansion coefficient α ₂ from 5 × 10 ⁻⁵ to 1 × 10 ⁻⁴ / ° C. and 10 ° C. higher than the glass transition temperature to 40 ° C. higher than the glass transition temperature is 1 × 10 ⁻⁴ 3 × 10 ⁻⁴ / ° C. When the average linear expansion coefficient α ₁ is less than 5 × 10 ⁻⁵ / ° C. or the average linear expansion coefficient α ₂ is less than 1 × 10 ⁻⁴ / ° C., it is used for manufacturing a liquid crystal display device by a dropping method. When used as a sealing agent, a sealing agent or a vertical conduction material, even if the main curing by heating is performed after the temporary curing by light irradiation, the adhesion to the substrate or the like is insufficient, and sufficient adhesion cannot be obtained. When the average linear expansion coefficient α ₁ exceeds 1 × 10 ⁻⁴ / ° C. or the average linear expansion coefficient α ₂ exceeds 3 × 10 ⁻⁴ / ° C., the heat resistance and cooling cycle characteristics of the obtained liquid crystal display device Is inferior.

The photothermosetting resin composition of the present invention preferably has a volume resistance of 10 ¹³ Ω · cm or more when cured by light and / or heat, and a dielectric constant of 3 or more at 100 kHz. . When the volume resistance value is less than 1 × 10 ¹³ Ω · cm, it means that the curable resin composition of the present invention contains ionic impurities, and is used as a sealing agent, a sealing agent or a vertical conduction material. When the current is applied, ionic impurities are eluted into the liquid crystal, which affects the liquid crystal driving voltage and may cause display unevenness. In addition, the dielectric constant of the liquid crystal is usually about ε // (parallel) is about 10 and ε⊥ (vertical) is about 3.5. Therefore, when the dielectric constant is less than 3, the curable resin composition is in the liquid crystal. May affect the liquid crystal driving voltage and cause display unevenness.

The preferable lower limit of the tensile elastic modulus at 25 ° C. of the cured product when cured by light and / or heat is 400 MPa, and the preferable upper limit is 4000 MPa. If it is less than 400 MPa, the heat resistance may be inferior, and if it exceeds 4000 MPa, the impact resistance may be inferior.
Moreover, the preferable lower limit of the value obtained by dividing the tensile elastic modulus at 25 ° C. of the cured product when cured by light and / or heat by the tensile elastic modulus at 150 ° C. is 100, in the photothermosetting resin composition of the present invention. A preferred upper limit is 250. If it is less than 100, the flexibility of the cured product is inferior, so that the adhesion to the substrate or the like may be insufficient, and if it exceeds 250, the heat resistance may be inferior.

The lower limit of the glass transition temperature of the cured product when the photothermosetting resin composition of the present invention is cured by light and / or heat is 80 ° C., and the preferable upper limit is 150 ° C. If it is less than 80 ° C., it may be inferior in moisture resistance, and if it exceeds 150 ° C., it may be too rigid and inferior in adhesion to the substrate.
In addition, the said glass transition temperature is the value measured on conditions with a temperature increase rate of 5 degree-C / min and a frequency of 10 Hz by DMA method. However, since the measurement of the glass transition temperature by the DMA method requires a large amount of sample, when only a small amount of sample can be obtained, it is preferable to perform the measurement by the DSC method at a temperature rising rate of 10 ° C./min. In general, the glass transition temperature measured by the DSC method is about 30 ° C. lower than the glass transition temperature measured by the DMA method. Therefore, when measuring a glass transition temperature by DSC method, the preferable minimum of the glass transition temperature of the said hardened | cured material is 50 degreeC, and a preferable upper limit is 120 degreeC.

In the photothermosetting resin composition of the present invention, the preferable lower limit of the contact angle with water of the cured product when cured by light and / or heat is 20 degrees, and the preferable upper limit is 80 degrees. If it is less than 20 degrees, the moisture resistance may be inferior. If it exceeds 80 degrees, it may elute into the liquid crystal before curing.
The contact angle with water is determined by applying a photothermosetting resin composition of the present invention thinly and uniformly onto a glass plate and curing it, then forming water droplets on the glass plate and forming a contact angle measuring device (for example, For example, manufactured by Kyowa Interface Science Co., Ltd.).

  It does not specifically limit as a method to manufacture the photothermosetting resin composition of this invention, The said reactive resin and the said inorganic particle, the hardening | curing agent mix | blended as needed, etc. are mixed by a conventionally well-known method. Methods and the like. At this time, in order to remove ionic impurities, it may be brought into contact with an ion-adsorbing solid such as a layered silicate mineral.

The photothermosetting resin composition of the present invention is cured by light or heat, has a small linear expansion coefficient after curing, and is excellent in adhesiveness with a substrate or the like, so that a liquid crystal display device is produced by a dropping method. It is suitable as a sealing agent for liquid crystal display elements and a sealing agent for liquid crystal display elements.
The sealing agent for liquid crystal display elements and the sealing agent for liquid crystal display elements which use the photothermosetting resin composition of the present invention are also one aspect of the present invention.

In addition, in the liquid crystal display device, a vertical conduction material is generally used in order to make vertical conduction between opposing electrodes on two transparent substrates. The vertical conduction material is usually configured by containing conductive fine particles in a curable resin composition.
The vertical conduction material for a liquid crystal display element comprising the photothermosetting resin composition of the present invention and conductive fine particles is also one aspect of the present invention.

  The conductive fine particles are not particularly limited. For example, metal fine particles; those obtained by subjecting resin substrate fine particles to metal plating (hereinafter referred to as metal plating fine particles); Those coated (hereinafter referred to as coated metal plated fine particles); and those metal fine particles, metal plated fine particles, and coated metal plated fine particles having protrusions on the surface. Especially, since it is excellent in the uniform dispersibility in a resin composition and electroconductivity, the metal plating fine particle and covering metal plating fine particle which gave gold plating are preferable.

  The preferable lower limit of the amount of the conductive fine particles to 100 parts by weight of the photothermosetting resin composition is 0.2 parts by weight, and the preferable upper limit is 5 parts by weight.

  The method for producing the vertical conducting material for a liquid crystal display element of the present invention is not particularly limited. For example, the photothermosetting resin composition, the conductive fine particles, and the like are blended so as to have a predetermined blending amount, and a vacuum planetary planet is obtained. The method of mixing with a type | formula stirring apparatus etc. is mentioned.

  Furthermore, a liquid crystal display device using at least one of the sealing agent for liquid crystal display elements of the present invention, the sealing agent for liquid crystal display elements of the present invention, and the vertical conduction material for liquid crystal display elements of the present invention is also included in the present invention. One.

  As a method for producing the liquid crystal display device of the present invention using at least one of the sealing agent for liquid crystal display elements of the present invention, the sealing agent for liquid crystal display elements of the present invention, and the vertical conduction material for liquid crystal display elements of the present invention. It is not specifically limited, For example, it can manufacture with the following method.

  As a manufacturing method of a liquid crystal display device by a dripping method, for example, a rectangular seal is applied to one of two transparent substrates with electrodes such as an ITO thin film by screen printing, dispenser application, etc. Form a pattern. Further, a vertical conduction pattern is formed on a predetermined electrode on the other transparent substrate by screen printing, dispenser application or the like of the vertical conduction material for a liquid crystal display element of the present invention. Instead of using a vertical conduction material, it is possible to incorporate conductive fine particles in the sealant to achieve vertical conduction. Next, a liquid crystal micro-droplet is dropped onto the entire surface of the transparent substrate frame in an uncured state of the sealant, and the other transparent substrate is immediately overlapped in an uncured state of the vertically conductive material, and the seal portion and the vertically conductive material portion Preliminary curing is performed by irradiating with UV rays. After that, heating is performed at the time of liquid crystal annealing to perform main curing, and a liquid crystal display device is manufactured.

  Since the present invention has the above-described configuration, the photothermosetting resin composition and the liquid crystal are excellent in adhesion because they do not cause cell gap unevenness at the time of curing, particularly when used in the production of a liquid crystal display device by a dropping method. It became possible to obtain a sealing agent for display elements, a sealing agent for liquid crystal display elements, a vertical conduction material for liquid crystal display elements, and a liquid crystal display device.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(A) Synthesis of acrylic acid-modified phenol novolac epoxy resin Liquid phenol novolac type epoxy resin (manufactured by Dow Chemical Co .: DEN 431) 1000 parts by weight, p-methoxyphenol 2 parts by weight as a polymerization inhibitor, reaction As a catalyst, 2 parts by weight of triethylamine and 200 parts by weight of acrylic acid were reacted for 5 hours while stirring at 90 ° C. while feeding air. 100 parts by weight of the obtained resin was filtered through a column packed with 10 parts by weight of a natural combination of quartz and kaolin (manufactured by Hoffman Mineral Co., Ltd., Siritin V85) to adsorb ionic impurities in the reaction product. An acid-modified phenol novolac epoxy resin (50% partially acrylated product) was obtained.

(B) Synthesis of acrylic acid-modified propylene oxide bisphenol A epoxy resin Liquid polyoxyalkylene bisphenol A diglycidyl ether (Asahi Denka Kogyo Co., Ltd., EP4000S) 1440 parts by weight, p-methoxyphenol 2 parts by weight as a polymerization inhibitor, reaction As a catalyst, 2 parts by weight of triethylamine and 200 parts by weight of acrylic acid were reacted for 5 hours while stirring at 90 ° C. while feeding air. 100 parts by weight of the obtained resin was filtered through a column packed with 10 parts by weight of a natural combination of quartz and kaolin (manufactured by Hoffman Mineral Co., Ltd., Siritin V85) to adsorb ionic impurities in the reaction product. An acid-modified propylene oxide bisphenol A epoxy resin (50% partially acrylated product) was obtained.

(C) Synthesis of urethane-modified partially acrylated product 134 parts by weight of trimethylolpropane, 0.2 part by weight of BHT as a polymerization initiator, 0.01 part by weight of dibutyltin dilaurate as a reaction catalyst, and 666 parts by weight of isophorone diisocyanate are added at 60 ° C. The reaction was carried out for 2 hours with stirring under reflux. Next, 25.5 parts by weight of 2-hydroxyethyl acrylate and 111 parts by weight of glycidol were added, and the mixture was allowed to react for 2 hours while stirring at 90 ° C. while feeding air. 100 parts by weight of the obtained resin was filtered through a column packed with 10 parts by weight of a natural combination of quartz and kaolin (manufactured by Hoffman Mineral Co., Ltd., Siritin V85) in order to adsorb ionic impurities in the reaction product. A modified partially acrylated product was obtained.

(Example 1)
40 parts by weight of an acrylic acid-modified phenol novolac epoxy resin obtained in (A), 20 parts by weight of a urethane-modified partially acrylated product obtained in (C), a hydrazide-based curing agent (manufactured by Ajinomoto Fine Techno Co., Ltd.) as a latent thermosetting agent , Amicure VDH) 15 parts by weight, 2,2-diethoxyacetophenone as a photopolymerization initiator 1 part by weight, silica particles (average particle size 0.5 μm) 23 parts by weight, γ-glycidoxypropyltrimethoxysilane 1 part by weight The curable resin composition consisting of was sufficiently mixed using a three roll so as to be a uniform liquid to obtain a sealing agent.

The obtained sealing agent was applied to one of two transparent substrates with transparent electrodes with a dispenser so as to draw a rectangular frame. Subsequently, fine droplets of liquid crystal (manufactured by Chisso Co., Ltd., JC-5004LA) are dropped onto the entire surface of the transparent substrate, and the other transparent substrate is immediately overlaid, and a high-pressure mercury lamp is used as a seal portion to apply ultraviolet light at 50 mW / cm. ² for 60 seconds. Thereafter, liquid crystal annealing was performed at 120 ° C. for 1 hour for thermosetting to produce a liquid crystal display device.

(Example 2)
Instead of 20 parts by weight of the urethane-modified partially acrylated product obtained in (C), 20 parts by weight of the acrylic acid-modified propylene oxide bisphenol A epoxy resin obtained in (B) was used, and a hydrazide-based curing agent (Ajinomoto Fine Techno Co., Ltd.). The sealing agent was obtained in the same manner as in Example 1 except that 15 parts by weight of a hydrazide-based curing agent (manufactured by Nippon Hydrazine Kogyo Co., Ltd., NDH) was used instead of 15 parts by weight. A display device was produced.

(Comparative Example 1)
A curable resin composition comprising 35 parts by weight of urethane acrylate (AH-600, manufactured by Kyoeisha Chemical Co., Ltd.), 15 parts by weight of 2-hydroxybutyl acrylate, 50 parts by weight of isobornyl acrylate, and 3 parts by weight of benzophenone so as to become a uniform liquid. To obtain a photo-curing sealant, which was used to produce a liquid crystal display device.

(Comparative Example 2)
A curable resin composition comprising 50 parts by weight of a bisphenol A epoxy resin (manufactured by Japan Epoxy Resin, Epicoat 828US) and 25 parts by weight of a hydrazide-based curing agent (manufactured by Nippon Hydrazine Kogyo Co., Ltd., NDH) The roll was sufficiently mixed to obtain a sealant, which was used to produce a liquid crystal display device.

For the sealing agents prepared in Examples 1 and 2 and Comparative Examples 1 and 2, the average linear expansion coefficient after photocuring and photothermal curing as well as the volume resistance value after curing, dielectric constant at 100 kHz, and tension by the following methods The elastic modulus was evaluated, and color unevenness of the obtained liquid crystal display device was evaluated by the following method.
The results are shown in Table 1.

(Average linear expansion coefficient after photocuring and after photothermal curing)
After a sealing agent was applied thinly and uniformly on a polyfluorinated ethylene substrate, it was UV-cured under conditions of 3000 mJ / cm ² to produce a photocured sample having a size of 15 mm × 4 mm and a thickness of 0.6 mm. In addition, after a sealing agent is applied thinly and uniformly on a polyfluorinated ethylene substrate, it is UV-cured under conditions of 3000 mJ / cm ² and further heat-cured under conditions of 120 ° C. for 1 hour to obtain a size of 15 mm × 4 mm, thickness A photothermographic sample having a thickness of 0.6 mm was produced.
Using the “EXSTAR6000TMA / SS” manufactured by Seiko Denshi Kogyo Co., Ltd., the average linear expansion coefficient of the prepared photocured sample and photothermographic sample was set to an initial temperature of 35 ° C., a heating end temperature of 150 ° C., and a heating rate of 5 ° C./min. , Retention time: measured under measurement conditions of 0 min.
From the obtained value, the cured product when cured only by light and the cured product when cured by light and heat, from a temperature 40 ° C. lower than the glass transition temperature to a temperature 10 ° C. lower than the glass transition temperature. An average linear expansion coefficient α ₁ and an average linear expansion coefficient α ₂ from a temperature 10 ° C. higher than the glass transition temperature to a temperature 40 ° C. higher than the glass transition temperature were calculated.

(Volume resistance after curing)
Apply a thin and uniform sealant onto the chromium vapor deposition surface of the chromium vapor deposition glass substrate and then cure with ultraviolet rays to form an ultraviolet cured product with a size of 85 mm x 85 mm and a thickness of 3 mm. A chromium-deposited glass substrate was placed on the object side, a load was applied, and thermocompression bonding was performed on a hot plate at 120 ° C. for 1 hour to prepare a test sample. The area of the sealant (S (cm ² )) in this test sample is constant using a constant voltage generator (PA36-2A regulated DC power supply manufactured by Kenwood) between the chromium vapor deposition surfaces of the opposite chromium vapor deposition glass substrate. The voltage (A (A)) flowing through the membrane was measured with an ammeter (Advantest, R644C digital multimeter). When the film pressure (T (cm)) of the sealing agent was used, the volume resistivity (Ω · cm) was determined by the following formula.
Volume resistivity (Ω · cm) = (V · S) / (A · T)
However, the applied voltage was DC 500 V, and the conduction time was 1 minute.

(Dielectric constant at 100 kHz after curing)
A sealant was applied thinly and uniformly on a glass plate and then cured to prepare a test piece having a size of 60 mm × 60 mm and a thickness of 3 mm. Measured at a frequency of 100 kHz using a dielectric measurement electrode (Yokogawa HP, HP16451B) and an LCR meter (Hewlett Packard, 4284A) by a non-contact method (gap method) in accordance with ASTM D150. .

(Tensile modulus after curing)
After applying the sealant thinly and uniformly on a polyfluorinated ethylene substrate, it is cured with ultraviolet rays to form an ultraviolet cured product having a size of 50 mm × 5 mm and a thickness of 0.5 mm, and further heated at 120 ° C. for 1 hour. A test sample was prepared.
Using the “RSA II” manufactured by TA Instruments, the tensile elastic modulus of the prepared test sample, the length between grips: 30 mm, initial temperature: room temperature, heating end temperature: 150 ° C., rate of temperature increase : 5 ° C./min, data taken as interval, lower limit elastic modulus: 10 Pa, lower limit movement: 0.008 N, measurement frequency: 10 Hz, strain (E> 108): 0.1%, static / power ratio: 0, Measurement was performed under the conditions of an upper limit elongation: 50% and an elongation index: 1.

(Color unevenness evaluation)
About the obtained liquid crystal display device, the color unevenness generated in the liquid crystal was visually observed before and after being left at 60 ° C., 95% RH for 500 hours, and ◎ (no color unevenness), ○ (color unevenness was slight) , Δ (a little color unevenness), × (a considerable color unevenness), was evaluated in four stages. Here, the number of samples was 5 per section.

(Example 3)
After thoroughly mixing the curable resin composition obtained in the same manner as in Example 1 using three rolls so as to form a uniform liquid, the conductive fine particles are used with respect to 100 parts by weight of the curable resin composition. 2 parts by weight of gold-plated metal plating fine particles (manufactured by Sekisui Chemical Co., Ltd., Micropearl AU-206) were mixed and mixed with a vacuum planetary stirrer to prepare a vertical conduction material for a liquid crystal display element.

  A liquid crystal display device was produced in the same manner as in Example 1 except that a vertical conduction pattern was formed on the electrode for vertical conduction by applying the obtained vertical conduction material on a transparent substrate by a dispenser.

  The obtained liquid crystal display device was similarly evaluated for color unevenness, and the color unevenness generated in the liquid crystal of the vertical conduction material was visually observed. Also, the conductivity was good.

According to the present invention, when used for producing a liquid crystal display device by a dripping method, a photothermosetting resin composition having excellent adhesion without causing cell gap unevenness at the time of curing, and a sealing agent for liquid crystal display elements A liquid crystal display element sealing agent, a liquid crystal display element vertical conduction material, and a liquid crystal display device can be provided.

Claims (17)

A photothermosetting resin composition used in a liquid crystal dropping method, comprising a reactive resin having a cyclic ether group and a radical polymerizable functional group in one molecule, and inorganic particles having an average particle diameter of 1 μm or less,
The average linear expansion coefficient α ₁ from a temperature 40 ° C. lower than the glass transition temperature of the cured product when cured only by light to a temperature 10 ° C. lower than the glass transition temperature is 1 × 10 ^{−4 to} 5 × 10 ⁻⁴ / ° C. And an average linear expansion coefficient α ₂ from a temperature 10 ° C. higher than the glass transition temperature to a temperature 40 ° C. higher than the glass transition temperature is 2 × 10 ⁻⁴ to 1 × 10 ⁻³ / ° C. A photothermosetting resin composition. A photothermosetting resin composition used in a liquid crystal dropping method, comprising a reactive resin having a cyclic ether group and a radical polymerizable functional group in one molecule, and inorganic particles having an average particle diameter of 1 μm or less,
The average linear expansion coefficient α ₁ from a temperature 40 ° C. lower than the glass transition temperature of the cured product when cured by light and heat to a temperature 10 ° C. lower than the glass transition temperature is 5 × 10 ⁻⁵ to 1 × 10 ⁻⁴ / And the average linear expansion coefficient α ₂ from 10 ° C. higher than the glass transition temperature to 40 ° C. higher than the glass transition temperature is 1 × 10 ^{−4 to} 3 × 10 ⁻⁴ / ° C. A photothermosetting resin composition.   The photothermosetting resin composition according to claim 1 or 2, wherein the cyclic ether group is an epoxy group or an oxetane group.   The photothermosetting property according to claim 1, 2, or 3, wherein the functional group equivalent of the total of the cyclic ether group and the radical polymerizable functional group in the reactive resin is 2.5 to 5.5 mmol / g. Resin composition.   The photothermosetting resin composition according to claim 1, 2, 3 or 4, wherein the equivalent of the radical polymerizable functional group in the reactive resin is 2.0 to 5.0 mmol / g.   The value obtained by dividing the functional group equivalent of the radical polymerizable functional group in the reactive resin by the functional group equivalent of the cyclic ether group is 1 to 9, wherein Photothermosetting resin composition.   The reactive resin further has a cyclic structure having 24 or less atoms, and the equivalent of the cyclic structure in the reactive resin is 1.5 to 6.0 mmol / g. The photothermosetting resin composition according to 3, 4, 5, or 6.   The photothermosetting resin composition according to claim 7, wherein the cyclic structure is aromatic.   The photothermosetting resin composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the number average molecular weight of the reactive resin is 300 to 550.   The blending amount of the inorganic particles is 10 to 20 parts by weight with respect to 100 parts by weight of the photothermosetting resin composition, wherein the amount of the inorganic particles is 1, 2, 3, 4, 5, 6, 7, 8, or 9. The photothermosetting resin composition as described. The volume resistivity of the cured product when cured by light and / or heat is 10 ¹³ Ω · cm or more, and the dielectric constant at 100 kHz is 3 or more. The photothermosetting resin composition according to 5, 6, 7, 8, 9 or 10.   The tensile elastic modulus at 25 ° C of the cured product when cured by light and / or heat is 400 to 4000 MPa, characterized in that it is 1, 2, 3, 4, 5, 6, 7, 8, 9 The photothermosetting resin composition according to 10 or 11.   The value obtained by dividing the tensile elastic modulus at 25 ° C. of the cured product when cured by light and / or heat by the tensile elastic modulus at 150 ° C. is 100 to 250. The photothermosetting resin composition according to 4, 5, 6, 7, 8, 9, 10, 11 or 12.   A sealant for a liquid crystal display device comprising the photothermosetting resin composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13. .   A sealing agent for a liquid crystal display element comprising the photothermosetting resin composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13. .   14. A liquid crystal display element comprising the photothermosetting resin composition according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, and conductive fine particles. For vertical conduction material. A sealing agent for a liquid crystal display element according to claim 14, a sealing agent for a liquid crystal display element according to claim 15, and a vertical conduction material for a liquid crystal display element according to claim 16 are used. Liquid crystal display device.