JP7411693B2 - Photothermosetting resin composition, liquid crystal sealant containing the same, liquid crystal display panel, and manufacturing method thereof - Google Patents

Description

The present invention relates to a photothermosetting resin composition, a liquid crystal sealant containing the same, a liquid crystal display panel, and a method for manufacturing the same.

2. Description of the Related Art Display panels such as liquid crystal and organic EL are widely used as image display panels for various electronic devices such as mobile phones and personal computers. For example, a liquid crystal display panel consists of two transparent substrates with electrodes on their surfaces, a frame-shaped sealing member sandwiched between them, and a liquid crystal material sealed in an area surrounded by the sealing member. and has.

Here, the sealing member is required to have high adhesion to the substrate. If the sealing member peels off from the substrate, liquid crystal leakage or the like will occur, resulting in poor image display. Therefore, conventionally, a compound having a hydrophilic group (for example, a silane coupling agent, etc.) was included in the liquid crystal sealant for forming the sealing member, and the hydrophilic group in the sealing member and the hydrophilic group present on the substrate surface were combined. Their adhesion was enhanced by chemically bonding them.

Furthermore, Patent Document 1 proposes including core-shell type particles in a liquid crystal sealant for forming a sealing member. Specifically, core-shell structure fine particles (manufactured by Aica Kogyo Co., Ltd. F-351), ie, particles in which the core is polybutyl acrylate and the shell is polymethyl methacrylate, are described.

Japanese Patent Application Publication No. 2005-15757

Here, in a liquid crystal display panel, it is common to arrange alignment films on the surfaces of a pair of substrates to align liquid crystal in a desired direction. In conventional liquid crystal display panels, a sealing member is generally formed by applying a liquid crystal sealant to the outside of an alignment film disposed on a substrate. Therefore, it is only necessary to increase the adhesion between the substrate and the sealing member, and as described above, it has been possible to increase the adhesion of the sealing member to the substrate by adding a silane coupling agent or the like.

However, in recent years, there has been a demand for narrower frames for liquid crystal display panels. Therefore, it is required to form a sealing member by applying a liquid crystal sealant also to the region where the alignment film is arranged. However, recent alignment films are highly hydrophobic and have a small number of hydrophilic groups. In other words, the amount of groups capable of covalent bonding with hydrophilic groups in the liquid crystal sealant is small. Therefore, with conventional liquid crystal sealants, it has been difficult to sufficiently increase the adhesive strength between the sealing member obtained by applying the liquid crystal sealant and the substrate on which the alignment film is disposed. For example, when a load is applied to the liquid crystal display panel from the outside, there is a problem that the sealing member and the substrate peel off at the interface. Furthermore, it has been difficult to improve the adhesion between the substrate and the sealing member even with a liquid crystal sealant containing particles as described in Patent Document 1.

The present invention has been made in view of the above problems. The object of the present invention is to provide a photothermosetting resin composition that can form a sealing member with high adhesion to various substrates when used as a liquid crystal sealant, for example.

The present invention provides the following photothermosetting resin composition and a liquid crystal sealant containing the same.
[1] Photothermal curing containing a curable compound (A) having an ethylenically unsaturated double bond in the molecule, a photopolymerization initiator (B), a latent thermosetting agent (C), and organic fine particles (D) The organic fine particles (D) have an outer shell portion and a core portion, and the core portion is at least one of a conjugated diene rubber and a silicone rubber containing a structural unit derived from a conjugated diene. A photothermosetting resin composition comprising one.

[2] The organic fine particles (D) are composed of the outer shell part and the core part, and the core part contains a conjugated diene rubber containing a structural unit derived from a conjugated diene and an aromatic vinyl compound, The photothermosetting resin composition according to [1], wherein the outer shell portion contains a polymer having one or more structures selected from the group consisting of a methyl methacrylate structure, a styrene structure, an acrylonitrile structure, and a glycidyl structure.

[3] The photothermosetting resin composition according to [1] or [2], further containing an inorganic filler (E).
[4] The photothermosetting resin composition according to any one of [1] to [3], wherein the content of the organic fine particles (D) is 5 to 17% by mass.
[5] The latent thermosetting agent (C) is one or more selected from the group consisting of an organic acid dihydrazide-based thermally latent curing agent, an amine adduct-based thermally latent curing agent, and a polyamine-based thermally latent curing agent. The photothermosetting resin composition according to any one of [1] to [4], which is a curing agent.
[6] A liquid crystal sealant comprising the photothermosetting resin composition according to any one of [1] to [5] above.

The present invention provides the following method for manufacturing a liquid crystal display panel and a liquid crystal display panel obtained from the manufacturing method.
[7] A step of applying the liquid crystal sealant described in [6] above on the alignment film of one of a pair of substrates each having an alignment film to form a seal pattern, and a step of forming a seal pattern on the alignment film of one substrate, and forming a seal pattern on the alignment film of one of the substrates, each having an alignment film. A step of dropping liquid crystal on the one substrate and within the area of the seal pattern or onto the other substrate in a cured state, and a step of overlapping the one substrate and the other substrate via the seal pattern. and curing the seal pattern.

[8] The method for manufacturing a liquid crystal display panel according to [7], wherein in the step of curing the seal pattern, the seal pattern is cured by irradiating the seal pattern with light.
[9] The method for manufacturing a liquid crystal display panel according to [8], wherein the light irradiated onto the seal pattern includes light in the visible light region.
[10] The method for manufacturing a liquid crystal display panel according to [8] or [9], wherein in the step of curing the seal pattern, the seal pattern after being irradiated with light is further heated.
[11] A pair of substrates each having an alignment film, a frame-shaped sealing member disposed between the alignment films of the pair of substrates, and a space surrounded by the sealing member between the pair of substrates. a filled liquid crystal layer, wherein the sealing member is a cured product of the liquid crystal sealant according to [6].

According to the photothermosetting resin composition of the present invention, when used as a liquid crystal sealant, a sealing member capable of firmly adhering a pair of substrates can be obtained.

1. Photothermosetting resin composition The photothermosetting resin composition of the present invention comprises a curable compound (A) having an ethylenically unsaturated double bond in the molecule, a photopolymerization initiator (B), a latent thermosetting agent ( C) and specific organic fine particles (D).

As mentioned above, in conventional photothermosetting resin compositions (liquid crystal sealants), the adhesion between the cured product (sealing member) and the substrate is generally enhanced by chemical bonding. However, this method cannot sufficiently cope with cases where an alignment film is disposed on a substrate, and depending on the type of substrate, sufficient adhesion with the substrate cannot be obtained.

On the other hand, the photothermosetting resin composition of the present invention includes organic fine particles (D) having an outer shell part and a core part, and the core part of the organic fine particles (D) is a structural unit derived from a conjugated diene. Contains either conjugated diene rubber or silicone rubber. When the photothermosetting resin composition contains such organic fine particles (D), the residual stress generated when the photothermosetting resin composition is applied and cured is relaxed by the core of the organic fine particles (D). Ru. Therefore, stress is less likely to be applied between the substrate and the cured product. That is, even if an alignment film or the like is disposed on the substrate, peeling between the substrate and the photothermosetting resin composition (sealing member) is unlikely to occur. Furthermore, even if a load is applied to a liquid crystal display panel or the like containing a cured product (sealing member) of the photothermosetting resin composition, the organic fine particles (D) can disperse the load. Therefore, stress is less likely to act on the interface between the sealing member and the substrate, and peeling thereof is suppressed.

Hereinafter, each component in the photothermosetting resin composition of the present invention will be explained in detail.

1-1. Curable compound (A)
The curable compound (A) may be any compound having an ethylenically unsaturated double bond in its molecule. The curable compound (A) may be a monomer, oligomer or polymer. Examples of the curable compound (A) include compounds having a (meth)acryloyl group in the molecule. The number of (meth)acryloyl groups per molecule of the compound having the (meth)acryloyl group may be one or two or more. In this specification, the description of a (meth)acryloyl group means an acryloyl group, a methacryloyl group, or both. Moreover, the description "(meth)acrylate" means acrylate, methacrylate, or both. Further, the term (meth)acrylic means acrylic, methacrylic, or both.

Examples of the curable compound (A) containing one (meth)acryloyl group in one molecule include methyl (meth)acrylate, ethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. Contains (meth)acrylic acid alkyl ester.

Examples of the curable compound (A) having two or more (meth)acryloyl groups in one molecule include di(meth)acrylate derived from polyethylene glycol, propylene glycol, polypropylene glycol, etc.; tris(2-hydroxyethyl)isocyanate; di(meth)acrylate derived from nurate; di(meth)acrylate derived from diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol; 2 moles of ethylene oxide or propylene to 1 mole of bisphenol A Di(meth)acrylate derived from diol obtained by adding oxide; Di- or tri(meth)acrylate derived from triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane; Bisphenol A1 di(meth)acrylate derived from diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to mole; tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate; trimethylolpropane tri(meth)acrylate; or its oligomer; pentaerythritol tri(meth)acrylate or its oligomer; dipentaerythritol poly(meth)acrylate; tris(acryloxyethyl)isocyanurate; caprolactone-modified tris(acryloxyethyl)isocyanurate; caprolactone-modified tris(meth)acrylate poly(meth)acrylate of alkyl-modified dipentaerythritol; poly(meth)acrylate of caprolactone-modified dipentaerythritol; neopentyl hydroxypivalate glycol di(meth)acrylate; caprolactone-modified neopentyl glycol hydroxypivalate Di(meth)acrylates; ethylene oxide-modified phosphoric acid (meth)acrylates; ethylene oxide-modified alkylated phosphoric acid (meth)acrylates; oligo(meth)acrylates of neopentyl glycol, trimethylolpropane, pentaerythritol, and the like.

The curable compound (A) may further have an epoxy group in the molecule. The number of epoxy groups per molecule may be one, or two or more. When the curable compound (A) has not only a (meth)acryloyl group but also an epoxy group in the molecule, the photothermosetting resin composition can be cured by heat as well. In other words, it becomes possible to use both photocuring and thermosetting. When the photothermosetting resin composition has photocurability and thermosetting property, it becomes possible to cure the photothermosetting resin composition efficiently in a short time.

Examples of compounds having a (meth)acryloyl group and an epoxy group in the molecule include (meth)acrylic acid glycidyl ester obtained by reacting an epoxy compound and (meth)acrylic acid in the presence of a basic catalyst. included.

The epoxy compound to be reacted with (meth)acrylic acid may be a polyfunctional epoxy compound having two or more epoxy groups in the molecule, and the crosslinking density may be too high, resulting in poor adhesion of the cured product of the photothermosetting resin composition. From the viewpoint of suppressing a decrease in , bifunctional epoxy compounds are preferred. Examples of bifunctional epoxy compounds include bisphenol type epoxy compounds (bisphenol A type, bisphenol F type, 2,2'-diallylbisphenol A type, bisphenol AD type, hydrogenated bisphenol type, etc.), biphenyl type epoxy compounds, and naphthalene type epoxy compounds. Among these, bisphenol type epoxy compounds such as bisphenol A type and bisphenol F type are preferred from the viewpoint that the coating properties of the photothermosetting resin composition tend to be good. The curable compound (A) derived from a bisphenol type epoxy compound has advantages such as superior coating properties compared to the curable compound (A) derived from a biphenyl ether type epoxy compound.

Note that the curable compound (A) may contain only one type of the above compound, or may contain two or more types. In particular, the curable compound (A) is a compound (A1) having a (meth)acryloyl group in the molecule and no epoxy group, and a compound (A2) having a (meth)acryloyl group and an epoxy group in the molecule. ). For example, when the photothermosetting resin composition further contains another curable compound (for example, an epoxy compound) described below, the compatibility between the compound (A1) and the epoxy compound may be low. On the other hand, when the compound (A2) having an epoxy group is combined, the compatibility of each component in the photothermosetting resin composition increases. Generally, when a photothermosetting resin composition is used as a liquid crystal sealant, hydrophobic compounds (such as epoxy compounds) are more easily eluted into the liquid crystal than hydrophilic compounds, but compound (A1) and compound By combining (A2), elution of the epoxy compound into the liquid crystal can be easily suppressed. The mass ratio of compound (A2) to compound (A1) is preferably A2/A1=1/0.4 to 1/0.6.

Note that the content of the compound (A2) having a (meth)acryloyl group and an epoxy group in the molecule is not particularly limited, but is preferably 30% by mass or more, for example, based on the total amount of the curable compound (A).

Further, the weight average molecular weight of any of the above-mentioned curable compounds (A) is preferably about 310 to 1000. The weight average molecular weight of the curable compound (A) can be measured in polystyrene terms, for example, by gel permeation chromatography (GPC).

The content of the curable compound (A) is preferably 40 to 80% by mass, more preferably 50 to 75% by mass, based on the total amount of the photothermosetting resin composition. When the amount of the curable compound (A) is within this range, the strength of the resulting cured product (for example, a seal member) increases, and furthermore, the adhesiveness between the substrate and the cured product (seal member) can be improved.

1-2. Photopolymerization initiator (B)
The photopolymerization initiator is not particularly limited as long as it is a compound that can radically polymerize the curable compound (A) by irradiation with light. For example, it may be a self-cleavage type photopolymerization initiator or a hydrogenated inorganic type photopolymerization initiator.

Examples of self-cleavable photopolymerization initiators include alkylphenone compounds (for example, benzyl dimethyl such as 2,2-dimethoxy-1,2-diphenylethan-1-one (IRGACURE 651 manufactured by BASF)). Ketal; α-aminoalkylphenone such as 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one (BASF IRGACURE 907); 1-hydroxy-cyclohexyl-phenyl-ketone (BASF IRGACURE) 184), acylphosphine oxide type compounds (e.g. 2,4,6-trimethylbenzoindiphenylphosphine oxide etc.), titanocene type compounds (e.g. bis(η5-2,4-cyclopentadiene-1) -yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, etc.), acetophenone compounds (e.g. diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl) Propan-1-one, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ) Ketone, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone ), phenylglyoxylate compounds (e.g., methylphenylglyoxyester, etc.), benzoin ether compounds (e.g., benzoin, benzoin methyl ether, benzoin isopropyl ether, etc.), and oxime ester compounds (e.g., 1,2-octanedione). -1-[4-(phenylthio)-2-(O-benzoyloxime)] (manufactured by BASF IRGACURE OXE01), ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3 -yl]-1-(0-acetyloxime) (IRGACURE OXE02 manufactured by BASF), etc.).

Examples of hydrogen abstraction type photopolymerization initiators include benzophenone compounds (e.g., benzophenone, methyl-4-phenylbenzophenone o-benzoylbenzoate, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'- Methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, etc.), thioxanthone compounds (e.g. thioxanthone, 2-chlorothioxanthone (manufactured by Tokyo Kasei Kogyo Co., Ltd.), 1-chloro-4-propoxythioxanthone, 1-chloro-4-ethoxythioxanthone (Speedcure CPTX, manufactured by Lambson Limited), 2-isopropylxanthone (Speedcure ITX, manufactured by Lambson Limited) , 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone (Speedcure DETX manufactured by Lambson Limited), 2,4-dichlorothioxanthone, etc.), anthraquinone compounds (such as 2-methylanthraquinone, 2-ethyl Anthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone, 2-hydroxyanthraquinone (manufactured by Tokyo Kasei Kogyo Co., Ltd.), 2,6-dihydroxyanthraquinone (manufactured by Tokyo Kasei Kogyo Co., Ltd. Anthraflavic Acid), 2-hydroxymethylanthraquinone (2-(Hydroxymethyl)anthraquinone, manufactured by Junsei Kagaku Co., Ltd.) and benzyl compounds. The photothermosetting resin composition may contain only one type of photopolymerization initiator (B), or may contain two or more types of photopolymerization initiator (B).

The absorption wavelength of the photopolymerization initiator (B) is not particularly limited, and for example, a photopolymerization initiator (B) that absorbs light with a wavelength of 360 nm or more is preferable. Among these, a photopolymerization initiator (B) that absorbs light in the visible light region is more preferable, a photopolymerization initiator (B) that absorbs light in a wavelength range of 360 to 780 nm is even more preferable, and a photopolymerization initiator (B) that absorbs light in a wavelength range of 360 to 430 nm is more preferable. ) is particularly preferred.

Examples of the photopolymerization initiator (B) that absorbs light with a wavelength of 360 nm or more include alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, thioxanthone compounds, and anthraquinone compounds. , preferably oxime ester compounds.

Note that the structure of the photopolymerization initiator (B) can be specified by combining high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS) with NMR measurement or IR measurement.

The molecular weight of the photopolymerization initiator (B) is preferably 200 or more and 5000 or less, for example. When the molecular weight is 200 or more, when the photothermosetting resin composition is used as a liquid crystal sealant, the photopolymerization initiator (B) is difficult to dissolve into the liquid crystal. On the other hand, when the molecular weight is 5000 or less, the compatibility with the curable compound (A) increases, and the curability of the photothermosetting resin composition tends to improve. The molecular weight of the photopolymerization initiator (B) is more preferably 230 or more and 3000 or less, and even more preferably 230 or more and 1500 or less.

The molecular weight of the photopolymerization initiator (B) can be determined as the "relative molecular mass" of the molecular structure of the main peak detected when analyzed by high performance liquid chromatography (HPLC).

Specifically, a sample solution in which the photopolymerization initiator (B) is dissolved in THF (tetrahydrofuran) is prepared and subjected to high performance liquid chromatography (HPLC) measurement. Then, the area percentage of the detected peak (the ratio of the area of each peak to the total area of all peaks) is determined, and the presence or absence of the main peak is confirmed. The main peak refers to the peak with the highest intensity (the peak with the highest peak height) among all peaks detected at a detection wavelength characteristic of each compound (for example, 400 nm for a thioxanthone compound). The relative molecular mass corresponding to the peak apex of the detected main peak can be measured by liquid chromatography mass spectrometry (LC/MS).

The amount of the photopolymerization initiator (B) is preferably 0.01 to 10% by mass based on the above-mentioned curable compound (A). When the amount of the photopolymerization initiator (B) is 0.01% by mass or more based on the curable compound (A), the curability of the photothermosetting resin composition tends to be good. When the content of the photopolymerization initiator (B) is 10% by mass or less, when the photothermosetting resin composition is used as a liquid crystal sealant, the photopolymerization initiator (B) becomes difficult to elute into the liquid crystal. The content of the photopolymerization initiator (B) is more preferably 0.1 to 5% by mass, even more preferably 0.1 to 3% by mass, and 0.1 to 2.5% by mass based on the curable compound (A). % by weight is particularly preferred.

1-3. Latent thermosetting agent (C)
The latent thermosetting agent (C) does not cure the thermosetting compound (A) or other curable compounds described below under normal storage conditions (room temperature, under visible light, etc.), but when heated, It is a compound that hardens these compounds. When the photothermosetting resin composition contains the latent thermosetting agent (C), the photothermosetting resin composition becomes thermocurable. The latent thermosetting agent (C) is preferably a curing agent capable of curing an epoxy compound (hereinafter also referred to as "epoxy curing agent").

The epoxy curing agent preferably has a melting point of 50°C or more and 250°C or less, from the viewpoint of increasing the viscosity stability of the photothermosetting resin composition and not impairing the moisture resistance of the cured product. The temperature is more preferably 150°C or higher and 200°C or lower.

Examples of epoxy hardeners include organic acid dihydrazide-based heat latent hardeners, imidazole-based heat latent hardeners, dicyandiamide-based heat latent hardeners, amine adduct-based heat latent hardeners, and polyamine-based heat latent hardeners. Contains agents.

Examples of organic acid dihydrazide-based heat latent curing agents include adipic acid dihydrazide (melting point 181°C), 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin (melting point 120°C), 7,11-octa These include decadiene-1,18-dicarbohydrazide (melting point 160°C), dodecanedioic acid dihydrazide (melting point 190°C), and sebacic acid dihydrazide (melting point 189°C).

Examples of imidazole-based heat latent curing agents include 2,4-diamino-6-[2'-ethylimidazolyl-(1')]-ethyltriazine (melting point 215-225°C), and 2-phenylimidazole (melting point 137-147°C), etc.

Examples of the dicyandiamide-based thermally latent curing agent include dicyandiamide (melting point: 209°C).

The amine adduct-based thermal latent curing agent is a thermal latent curing agent consisting of an addition compound obtained by reacting an amine-based compound having catalytic activity with an arbitrary compound. Examples of amine adduct-based thermal latent curing agents include Amicure PN-40 (melting point 110°C) manufactured by Ajinomoto Fine-Techno, Amicure PN-23 (melting point 100°C) manufactured by Ajinomoto Fine-Techno, and Amicure PN manufactured by Ajinomoto Fine-Techno. -31 (melting point 115°C), Amicure PN-H (melting point 115°C) manufactured by Ajinomoto Fine-Techno, Amicure MY-24 (melting point 120°C) manufactured by Ajinomoto Fine-Techno, and Amicure MY-H (melting point 120°C) manufactured by Ajinomoto Fine-Techno. 131℃), etc.

The polyamine-based thermal latent curing agent is a thermal latent curing agent having a polymer structure obtained by reacting an amine with an epoxy. Examples include ADEKA Hardener EH4339S (softening point 120 to 130°C) manufactured by ADEKA. and ADEKA Hardener EH4357S (softening point 73-83°C).

Among the above, organic acid dihydrazide-based thermal latent curing agents, amine adduct-based thermal latent curing agents, and polyamine-based thermal latent curing agents are preferred from the viewpoint of availability, compatibility with other components, etc. . The latent thermosetting agent (C) may contain only one kind of epoxy curing agent, or may contain two or more kinds.

The content of the latent thermosetting agent (C) is preferably 3 to 30% by mass, more preferably 3 to 20% by mass, and even more preferably 5 to 20% by mass, based on the total amount of the photothermosetting resin composition. The photothermosetting resin composition of the present invention may be a one-component curable resin composition. One-component curable resin compositions have excellent workability because there is no need to mix the base resin and the curing agent during use.

The content of the latent thermosetting agent (C) is preferably 3.8 to 75% by mass, more preferably 3.8 to 50% by mass, and 5 to 40% by mass based on the above-mentioned curable compound (A). is even more preferable. When the content of the latent thermosetting agent (C) with respect to the curable compound (A) is 3.8% by mass or more, the curability of the curable compound (A) during heating is likely to be increased. On the other hand, when the amount is 75% by mass or less, when the photothermosetting resin composition is used as a liquid crystal sealant, the liquid crystal is unlikely to be contaminated by the latent thermosetting agent (C).

1-4. Organic fine particles (D)
The organic fine particles (D) may be particles having an outer shell portion and a core portion and containing conjugated diene rubber or silicone rubber in the core portion. Here, the core is a region located near the center of the organic fine particles (D) and imparts desired elasticity to the organic fine particles (D). On the other hand, the outer shell is a layered region disposed on the outermost surface side of the organic fine particles (D) from the core, and is a layered region that forms a phase between the organic fine particles (D) and other components in the photothermosetting resin composition. This layer is for increasing solubility. The outer shell portion may completely cover the core portion, or may cover only a portion of the core portion, but it is better for the outer shell portion to completely cover the core portion, since the organic fine particles (D) The affinity with other components can be improved, and the dispersibility of the organic fine particles (D) can be improved.

The organic fine particles (D) may include another layer between the outer shell and the core, but from the viewpoint of ease of preparing the organic fine particles (D), the outer shell and the core may be separated. Preferably, it consists of: Whether or not the organic fine particles (D) have an outer shell portion and a core portion can be determined by curing the photothermosetting resin composition with light and heat, and then identifying the cross section using a transmission electron microscope (TEM) or the like. can.

The core portion may contain at least one of conjugated diene rubber or silicone rubber, but may contain both. Further, the core portion may contain components other than these rubbers as long as the purpose of the present invention and curing are not impaired.

The conjugated diene rubber only needs to contain a structural unit derived from a conjugated diene, and may have only a structural unit derived from a conjugated diene. It may be a combination or the like.

Examples of conjugated dienes include isoprene, 1,3-butadiene, 2-chloro-1,3-butadiene, 2-methyl-1,3-butadiene, chloroprene, and the like. The conjugated diene rubber may contain only one type of structural unit derived from a conjugated diene, or may contain two or more types. Further, the amount of structural units derived from conjugated diene in the conjugated diene rubber is preferably 50 to 100% by mass based on the total amount of all structural units.

On the other hand, examples of vinyl monomers copolymerizable with conjugated dienes include aromatic vinyl monomers such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; vinyl carboxylic acid monomers such as acrylic acid and methacrylic acid; and acrylonitrile. , vinyl cyanide monomers such as methacrylonitrile; halogenated vinyl monomers such as vinyl chloride and vinyl bromide; vinyl acetate; alkene monomers such as ethylene, propylene, butylene, and isobutylene; diallyl phthalate, triallyl cyanurate, triallyl Includes polyfunctional monomers such as isocyanurate and divinylbenzene. The conjugated diene rubber may contain only one type of structural unit derived from these vinyl monomers, or may contain two or more types. The amount of structural units derived from the vinyl monomer in the conjugated diene rubber is preferably 0 to 50% by mass based on the total amount of all structural units.

Specific examples of conjugated diene rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), and ethylene propylene diene rubber (EPDM). , chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR).

On the other hand, examples of silicone rubber include rubbers obtained by polymerizing siloxane monomers, or copolymers of siloxane monomers and vinyl monomers copolymerizable with the siloxane monomers.

Examples of siloxane-based monomers include siloxane monomers with two alkyl and/or aryl groups, such as dimethylsiloxane, diethylsiloxane, methylphenylsiloxane, diphenylsiloxane, dimethylsiloxane-diphenylsiloxane; siloxanes with one alkyl or aryl group; Contains monomers, etc. On the other hand, the vinyl monomer copolymerizable with the siloxane monomer is the same as the vinyl monomer copolymerizable with the above-mentioned conjugated diene.

The core of the organic fine particles (D) preferably contains a conjugated diene rubber among the above, and further preferably contains a structural unit derived from a conjugated diene and an aromatic vinyl compound (the above-mentioned aromatic vinyl monomer). Styrene butadiene rubber (SBR) is particularly preferred.

The amount of the core portion in the whole organic fine particles (D) is preferably 60 to 90% by mass, more preferably 80 to 90% by mass. When the ratio of the core portion in the organic fine particles (D) is within the above range, sufficient elasticity can be obtained in the cured product of the photothermosetting resin composition. For example, the adhesive strength between the sealing member obtained from the curable resin composition and the substrate of the liquid crystal display panel is sufficiently increased. The content of the core in the organic fine particles (D) can be measured from the absorbance ratio of the spectrum of infrared spectroscopy.

Further, the shape of the core is not particularly limited, but is preferably spherical from the viewpoint of making the particle size uniform.

On the other hand, the outer shell portion of the organic fine particles (D) is a layer that has an affinity with the above-mentioned core portion and is capable of increasing the dispersibility of the organic fine particles (D) in the photothermosetting resin composition. If so, there are no particular restrictions. The outer shell portion can be made of a polymer of (meth)acrylate monomer or vinyl monomer. Such an outer shell can be formed, for example, by forming the above-mentioned core and then polymerizing (meth)acrylate monomer or vinyl monomer around the core.

Examples of (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl ( Alkyl (meth)acrylates such as meth)acrylate and behenyl (meth)acrylate; Aromatic ring-containing (meth)acrylates such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 4- Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate; Glycidyl (meth)acrylates such as glycidyl (meth)acrylate and glycidyl alkyl (meth)acrylate; Alkoxyalkyl (meth)acrylates; Allyl (meth)acrylate , allyl alkyl (meth)acrylate such as allyl alkyl (meth)acrylate; polyfunctional (meth)acrylate such as monoethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, etc. Acrylate; etc. are included.

On the other hand, examples of vinyl monomers include monomers similar to the vinyl monomers copolymerizable with the above-mentioned conjugated diene.

Among these, it is preferable that the outer shell portion contains a polymer having one or more structures selected from the group consisting of a methyl methacrylate structure, a styrene structure, an acrylonitrile structure, and a glycidyl structure. When the outer shell portion contains a polymer having such a structure, the compatibility between the above-mentioned curable compound (A) and the like and the organic fine particles (D) will be improved.

The amount of the outer shell portion in the whole organic fine particles (D) is preferably 10 to 40% by mass, more preferably 10 to 20% by mass. When the ratio of the outer shell portion in the organic fine particles (D) is within the above range, the dispersibility of the organic fine particles (D) will be good. The content of the outer shell in the organic fine particles (D) can be measured from the absorbance ratio of the spectrum of infrared spectroscopy.

Further, the shape of the organic fine particles (D) is not particularly limited, but is preferably substantially spherical. When the organic fine particles (D) are approximately spherical, the average particle diameter is preferably 0.1 to 0.8 μm, more preferably 0.1 to 0.6 μm. When the average particle diameter is within this range, it becomes possible to form a thin sealing member using the photothermosetting resin composition. The average particle diameter can be measured by microscopy, specifically by image analysis using an electron microscope. More specifically, the liquid crystal sealant is image-analyzed, 50 organic fillers having a particle diameter of 1 μm or less are selected, and the average value of the measured particle diameters is defined as the average particle diameter.

The content of the organic fine particles (D) is preferably 5 to 17% by mass, more preferably 7 to 16% by mass, and even more preferably 9 to 15% by mass, based on the total amount of the photothermosetting resin composition. When the amount of organic fine particles is 5% by mass or more, when the photothermosetting resin composition is used as a liquid crystal sealant, the adhesive strength between the cured product (sealing member) and the substrate becomes high. On the other hand, when the content of organic fine particles (D) is 17% by mass or less, the amount of other components (for example, curable compound (A)) becomes sufficient, and the strength of the cured product (sealing member) increases.

1-5. Inorganic filler (E)
The photothermosetting resin composition of the present invention may further contain an inorganic filler (E) if necessary. When the photothermosetting resin composition contains the inorganic filler (E), the viscosity of the photothermosetting resin composition, the strength of the cured product, the linear expansion property, etc. are likely to be improved.

Examples of the inorganic filler (E) include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, titanium nitride, aluminum oxide (alumina), zinc oxide, silicon dioxide, Includes potassium titanate, kaolin, talc, glass beads, sericite activated clay, bentonite, aluminum nitride, silicon nitride, etc. Among them, silicon dioxide and talc are preferred.

The shape of the inorganic filler (E) may be a regular shape, such as a spherical shape, a plate shape, or a needle shape, or may be an amorphous shape. When the inorganic filler (E) is spherical, the average primary particle diameter of the inorganic filler (E) is preferably 1.5 μm or less, and the specific surface area is more preferably 0.5 to 20 m ² /g. The average primary particle diameter of the inorganic filler (E) can be measured by the laser diffraction method described in JIS Z8825-1. The specific surface area of the filler can be measured by the BET method described in JIS Z8830.

The content of the inorganic filler (E) is preferably 1 to 45% by mass based on the total amount of the photothermosetting resin composition. When the content of the inorganic filler (E) is 1% by mass or more, the moisture resistance of the cured product of the photothermocurable resin composition tends to increase, and when the content is 45% by mass or less, the coating of the photothermocurable resin composition tends to increase. Engineering stability is less likely to be impaired. The content of the inorganic filler (E) is more preferably 3 to 30% by mass based on the photothermosetting resin composition.

1-6. Other curable compounds The photothermosetting resin composition may further contain a thermosetting compound. However, the thermosetting compound is a compound different from the above-mentioned curable compound (A).

Examples of thermosetting compounds include epoxy compounds having an epoxy group in the molecule. Epoxy compounds may be monomers, oligomers or polymers. When the photothermosetting resin composition contains an epoxy compound, the display characteristics of the resulting liquid crystal panel will be improved, and the moisture resistance of the cured product (sealing member) will be improved.

It is particularly preferable that the epoxy compound has an aromatic ring. Further, the weight average molecular weight of the epoxy compound is preferably 500 to 10,000, more preferably 1,000 to 5,000. The weight average molecular weight of the epoxy compound is measured in terms of polystyrene by gel permeation chromatography (GPC).

Examples of aromatic epoxy compounds include aromatic diols represented by bisphenol A, bisphenol S, bisphenol F, bisphenol AD, etc., and diols obtained by modifying these aromatic diols with ethylene glycol, propylene glycol, alkylene glycol, etc. Aromatic polyglycidyl ether compounds obtained by the reaction of phenol or cresol with formaldehyde, polyphenols represented by polyalkenylphenols and their copolymers, etc., and epichlorohydrin. Novolac-type polyglycidyl ether compounds obtained by the reaction; glycidyl ether compounds of xylylene phenol resin, etc. are included. Among them, cresol novolac type epoxy compounds, phenol novolac type epoxy compounds, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, triphenolmethane type epoxy compounds, triphenolethane type epoxy compounds, trisphenol type epoxy compounds, dicyclopentadiene type. Epoxy compounds, diphenyl ether type epoxy compounds or biphenyl type epoxy compounds are preferred. The photothermosetting resin composition may contain only one kind of epoxy compound, or may contain two or more kinds of epoxy compounds.

The epoxy compound may be liquid or solid. From the viewpoint of easily increasing the moisture resistance of the cured product, solid epoxy compounds are preferred. The softening point of the solid epoxy compound is preferably 40°C or higher and 150°C or lower. The softening point can be measured by the ring and ball method specified in JIS K7234.

The content of the thermosetting compound is preferably 3 to 20% by mass based on the photothermosetting resin composition. When the amount of the thermosetting compound is 3% by mass or more, the moisture resistance of the cured product (sealing member) of the photothermosetting resin composition can be easily improved. When the content of the thermosetting compound is 20% by mass or less, excessive viscosity increase is unlikely to occur in the photothermosetting resin composition. The amount of the thermosetting compound is more preferably 3 to 15% by mass, and even more preferably 4 to 15% by mass, based on the photothermosetting resin composition.

The content of the thermosetting compound is preferably 3.8 to 50% by mass, more preferably 5 to 30% by mass based on the curable compound (A). When the content of the thermosetting compound relative to the curable compound (A) is 3.8% by mass or more, the moisture resistance of the cured product and the adhesive strength to the glass substrate further increase. On the other hand, when the content is 50% by mass or less, the compatibility with the curable compound (A) tends to be good during production.

1-7. Other Compounds The photothermosetting resin composition of the present invention may optionally contain a thermal radical polymerization initiator, a coupling agent such as a silane coupling agent, an ion trapping agent, an ion exchange agent, a leveling agent, a pigment, a dye, and an additive. It may further contain additives such as sensitizers, plasticizers, and antifoaming agents.

Examples of the silane coupling agent include vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and the like. The content of the silane coupling agent is preferably 0.01 to 5% by mass based on the curable compound (A). When the content of the silane coupling agent is 0.01% by mass or more, the cured product of the photothermosetting resin composition tends to have sufficient adhesiveness.

The photothermosetting resin composition of the present invention may further contain a spacer or the like for adjusting the gap of the liquid crystal display panel.

The total amount of other components is preferably 1 to 50% by mass based on the total amount of the photothermosetting resin composition. When the total amount of other components is 50% by mass or less, the viscosity of the photothermosetting resin composition is less likely to increase excessively, and the coating stability of the photothermosetting resin composition is less likely to be impaired.

1-8. Physical Properties of Photothermosetting Resin Composition The viscosity of the photothermosetting resin composition of the present invention at 25° C. and 2.5 rpm using an E-type viscometer is preferably 200 to 450 Pa·s, more preferably 300 to 400 Pa·s. . When the viscosity is within the above range, the photothermosetting resin composition will have good applicability with a dispenser.

The photothermosetting resin composition of the present invention can be used, for example, as a sealant. The photothermosetting resin composition is particularly suitable as a display element sealant used for sealing display elements such as liquid crystal display elements, organic EL elements, and LED elements. Furthermore, the photothermosetting resin composition of the present invention is highly suitable for use as a liquid crystal sealant for liquid crystal dropping methods because it hardly contaminates liquid crystals.

2. Liquid Crystal Display Panel and Manufacturing Method Thereof The liquid crystal display panel of the present invention includes a pair of substrates (a display substrate and a counter substrate) each having an alignment film, and a frame-shaped seal disposed between the alignment films of the pair of substrates. and a liquid crystal layer filled in a space surrounded by the sealing member between the pair of substrates. The sealing member is a cured product of the above-mentioned photothermosetting resin composition (liquid crystal sealant).

Both the display substrate and the counter substrate are transparent substrates. The material of the transparent substrate may be an inorganic material such as glass, or a plastic such as polycarbonate, polyethylene terephthalate, polyether sulfone, and PMMA.

A matrix of TFTs, color filters, black matrices, etc. may be arranged on the surface of the display substrate or the counter substrate. An alignment film is further arranged on the surface of the display substrate or the counter substrate. The alignment film contains a known organic alignment agent or inorganic alignment agent.

As described above, sealing members obtained from common liquid crystal sealants may have low adhesion to these alignment films. On the other hand, the above-mentioned photothermosetting resin composition (liquid crystal sealant) can alleviate the residual stress generated in the sealing member during curing, and can absorb the stress applied to the liquid crystal display panel from the outside. Therefore, even if the sealing member is placed in the area where the alignment film is formed, peeling is unlikely to occur at these interfaces. Therefore, in the liquid crystal display panel of the present invention, it is possible to realize a narrow frame.

A liquid crystal display panel is manufactured using the liquid crystal sealant of the present invention. Methods for manufacturing liquid crystal display panels generally include a liquid crystal dropping method and a liquid crystal injection method, and the liquid crystal display panel of the present invention is preferably manufactured by the liquid crystal dropping method.

The manufacturing method of liquid crystal display panels using the liquid crystal dripping method is as follows:
1) A step of applying the above-mentioned liquid crystal sealant onto the alignment film of one of a pair of substrates each having an alignment film to form a seal pattern;
2) Dropping liquid crystal onto one substrate and within the area surrounded by the seal pattern, or onto the other substrate while the seal pattern is uncured;
3) a step of overlapping one substrate and the other substrate via a seal pattern;
4) curing the seal pattern.

In the step 2), the uncured state of the seal pattern means a state where the curing reaction of the liquid crystal sealant has not progressed to the gelation point. Therefore, in step 2), in order to suppress dissolution of the liquid crystal sealant into the liquid crystal, the seal pattern may be semi-cured by light irradiation or heating. One substrate and the other substrate are each a display substrate or a counter substrate.

In step 4), only curing by light irradiation may be performed, but curing by heating may be performed after curing by light irradiation. By curing by light irradiation, the liquid crystal sealing agent can be cured in a short time, so dissolution into the liquid crystal can be suppressed. By combining curing by light irradiation and curing by heating, damage to the liquid crystal layer caused by light can be reduced compared to the case of curing only by light irradiation.

The light to be irradiated is appropriately selected depending on the type of photopolymerization initiator (B) in the above-mentioned liquid crystal sealant (photothermosetting resin composition), but light in the visible light region is preferable, for example, light in the visible light range, for example, in the wavelength range of 370 to 370. Preferably, the light is 450 nm. This is because light of the above wavelength causes relatively little damage to the liquid crystal material and drive electrodes. For light irradiation, a known light source that emits ultraviolet rays or visible light can be used. When irradiating visible light, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a xenon lamp, a fluorescent lamp, etc. can be used.

The light irradiation energy may be any energy that can cure the curable compound (A). The photocuring time is, for example, about 10 minutes, although it depends on the composition of the liquid crystal sealant.

The thermosetting temperature is, for example, 120° C., although it depends on the composition of the liquid crystal sealant, and the thermosetting time is about 2 hours.

The present invention will be explained in detail based on Examples, but the present invention is not limited to these Examples.

1. Preparation of curable compound (A) <Synthesis example 1: Curable compound (A-1)>
160 g of liquid bisphenol F type epoxy resin (Epotote YDF-8170C, manufactured by Toto Kasei Co., Ltd., epoxy equivalent: 160 g/eq), 0.1 g of polymerization inhibitor (p-methoxyphenol), 0.2 g of catalyst (triethanolamine) , and 43.0 g of methacrylic acid were charged into the flask. Then, dry air was fed into the mixture, and the mixture was allowed to react at 90° C. for 5 hours while being refluxed and stirred. The obtained compound was washed 20 times with ultrapure water to obtain a methacrylic acid partially modified bisphenol F type epoxy resin (curable compound (A-1)).

<Synthesis Example 2: Curable compound (A-2)>
116 g of 2-hydroxyethyl acrylate, 0.1 g of a polymerization inhibitor (p-methoxyphenol), and 100 g of succinic anhydride were charged into a flask. Then, dry air was introduced and the reaction was carried out for 5 hours while stirring and refluxing at 90°C. Subsequently, 170 g of bisphenol A diglycidyl ether was added, and the mixture was similarly reacted at 90° C. for 5 hours while stirring under reflux. The obtained compound was washed 20 times with ultrapure water to obtain a curable compound (A-2).

<Synthesis Example 3: Curable compound (A-3)>
160 g of liquid bisphenol F type epoxy resin (Epotote YDF-8170C, manufactured by Toto Kasei Co., Ltd., epoxy equivalent 160 g/eq), 0.1 g of polymerization inhibitor (p-methoxyphenol), 0.2 g of catalyst (triethanolamine) , and 81.7 g of methacrylic acid were placed in a flask, and the mixture was reacted at 90° C. for 5 hours while blowing dry air and stirring under reflux. The obtained compound was washed 20 times with ultrapure water to obtain a partially modified bisphenol F type epoxy resin containing 95% methacrylic acid (curable compound (A-3)).

<Preparation of curable compound (A-4)>
As the curable compound (A-4), an acrylic resin (polyethylene glycol diacrylate, Light Acrylate 14EG-A, manufactured by Kyoeisha Chemical) was used.

2. Preparation of organic fine particles (D) <Synthesis example 4: Organic fine particles (D-1)>
- Preparation of emulsion D' containing the core In a nitrogen-substituted autoclave equipped with a stirrer, 500 parts by mass of deionized water, 3 parts by mass of sodium lauryl sulfate, 0.6 parts by mass of potassium persulfate, 187.5 parts by mass of butadiene, and 62.5 parts by mass of styrene were charged and reacted at 70°C for 10 hours. After the obtained emulsion was cooled to room temperature, ion-exchanged water was added to adjust the solid content to 30% by mass.

- Formation of the outer shell In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer, 500 parts by mass of emulsion D' containing the above-mentioned core, 169 parts by mass of ion-exchanged water, and 0.5 parts by mass of sodium lauryl sulfate were added. 4 parts by mass were charged, and the temperature was raised to 70° C. while stirring and purging with nitrogen. The internal temperature was maintained at 70°C, and 0.5 parts by mass of potassium persulfate was added as a polymerization initiator. Furthermore, a monomer mixture solution in which 23 parts by mass of styrene, 19 parts by mass of methyl methacrylate, 12 parts by mass of acrylonitrile, and 15 parts by mass of glycidyl methacrylate were mixed in advance was continuously dropped into the reaction solution over a period of 3 hours. After completion of the dropping, aging was carried out for 3 hours. After aging, the obtained aqueous emulsion was cooled to room temperature, and then a spray dryer was used to obtain organic fine particles (D-1) having an average particle size of 0.2 μm.

<Synthesis Example 5: Synthesis of organic fine particles (D-2)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer, 500 parts by mass of the emulsion D' containing the core obtained in Synthesis Example 4, 169 parts by mass of ion-exchanged water, and 0.4 parts by mass of sodium lauryl sulfate were added. Parts by mass were charged, and the temperature was raised to 70° C. while stirring and purging with nitrogen. The internal temperature was maintained at 70° C., and 0.5 parts by mass of potassium persulfate was added as a polymerization initiator. Furthermore, a monomer mixture containing 23 parts by mass of styrene, 23.3 parts by mass of methyl methacrylate, 12 parts by mass of acrylonitrile, and 10.8 parts by mass of n-butyl methacrylate was continuously added dropwise into the reaction solution over a period of 3 hours. did. After completion of the dropping, aging was carried out for 3 hours. After aging, the obtained aqueous emulsion was cooled to room temperature, and then a spray dryer was used to obtain organic fine particles (D-2) having an average particle size of 0.2 μm.

3. Preparation of other materials The following materials were used as other materials.
・Epoxy compound: Epicote 1004, manufactured by JER, softening point 97°C
・Photopolymerization initiator (B): IRGACURE OXE01, manufactured by BASF ・Latent thermosetting agent (C): Adipic acid dihydrazide (ADH, manufactured by Nippon Kasei Co., Ltd., melting point 177-184°C)
・Inorganic filler (E): Silica particles (S-100, manufactured by Nippon Shokubai Kagaku Co., Ltd.)
・Other particles:
Fine particle polymer (F351, manufactured by Aica Kogyo Co., Ltd. (core-shell particles in which the core is a polymer of n-butyl acrylate and the shell is polymethyl methacrylate))
Polymethylsilsesquioxane particles (MSP-N080, manufactured by Nikko Rica)
Polymethylsilsesquioxane particles (MSP-N050, manufactured by Nikko Rica)
Polymethylsilsesquioxane particles (X-52-854, manufactured by Shin-Etsu Chemical)
Melamine/formaldehyde condensate (Epostor S, manufactured by Nippon Shokubai Co., Ltd.)
Single layer polymethyl methacrylate (Art Pearl J-3PY, manufactured by Negami Kogyo Co., Ltd.)
・Silane coupling agent: KBM-403

4. Preparation of photothermosetting resin composition <Example 1>
40 parts by mass of epoxy compound, 230 parts by mass of curable compound (A-1) obtained in Synthesis Example 1, 50 parts by mass of curable compound (A-2) obtained in Synthesis Example 2, 50 parts by mass of curable compound (A-2) obtained in Synthesis Example 3. 250 parts by mass of curable compound (A-3), 150 parts by mass of curable compound (A-4), 50 parts by mass of latent thermosetting agent (C), 60 parts by mass of inorganic filler (E), Synthesis Example 4 150 parts by mass of the curable resin (D-1) obtained in step 1, 10 parts by mass of a silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and 10 parts by mass of photopolymerization initiator (B) were mixed into a triple roll. A photothermosetting resin composition was obtained by sufficiently mixing the mixture to form a uniform liquid.

<Examples 2 to 6 and Comparative Examples 1 to 6>
A photothermosetting resin composition was prepared in the same manner as in Example 1, except that the composition was changed to the one shown in Table 1.

5. Evaluation The adhesive strength of the photothermosetting resin compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 6 was evaluated by the following method.

<Adhesive strength test>
The obtained photothermosetting resin composition was applied to a 40 mm x 45 mm glass substrate (RT-DM88-PIN, EHC) on which a transparent electrode and an alignment film were previously formed on the entire surface using a dispenser (Shotmaster, manufactured by Musashi Engineering Co., Ltd.). A rectangular line-shaped seal pattern (cross-sectional area: 2500 μm ² ) of 38 mm×38 mm was formed on the alignment film (manufactured by Co., Ltd.). Next, a pair of glass substrates were bonded together under reduced pressure so as to be perpendicular to the glass substrate on which the seal pattern was formed, and then they were bonded together while being exposed to the atmosphere. After holding the two bonded glass substrates in a light-shielding box for 1 minute, they were irradiated with light containing 3000 mJ/cm ² of visible light (light with a wavelength of 370 to 450 nm), and then heated at 120°C for 1 hour. A test piece was obtained.

A portion 4.5 mm from the corner (outside the line) of the seal pattern of the obtained test piece was indented vertically at a speed of 5 mm/min using an indentation tester (Model 210, manufactured by Intesco) to determine the photothermosetting resin composition. The stress when the cured product peeled off was measured. The adhesive strength was determined by dividing the stress by the line width of the cured product. The results are shown in Table 1.

As shown in Examples 1 to 6 in Table 1, one or more selected from the group consisting of rubber and silicone rubber, which have an outer shell and a core, and the core has a structural unit derived from a conjugated diene. All of the photothermosetting resin compositions containing this rubber gave good results in adhesive strength tests. It is thought that the residual stress generated when the photothermosetting resin composition is cured is relaxed by the organic fine particles (D), and that the organic fine particles (D) disperse the stress when external stress is applied. Therefore, it is presumed that in Examples 1 to 6, peeling at the interface between the cured product and the substrate was less likely to occur.

On the other hand, even if the particles have a core-shell structure, if the core does not contain the above-mentioned rubber, the residual stress and external stress will not be sufficiently dispersed, and the results of the adhesive strength test will be low (comparison). Example 1). Furthermore, the effect of improving adhesive strength was not obtained with polymethylsilsesquioxane particles having no core and outer shell, particles made of melamine/formaldehyde condensate, polymethyl methacrylate, etc. (Comparative Example 2-6).

This application claims priority based on Japanese Patent Application No. 2020-018755 filed on February 6, 2020. All contents described in the specification of the application are incorporated herein by reference.

According to the photothermosetting resin composition of the present invention, a cured product with high adhesiveness to various substrates can be obtained. Therefore, the photothermosetting resin composition is very useful as a sealant for various liquid crystal display devices.

Claims (11)

Photothermal curing containing a curable compound (A) having an ethylenically unsaturated double bond and an epoxy group in the molecule, a photopolymerization initiator (B), a latent thermosetting agent (C), and organic fine particles (D) is a resin composition,
The organic fine particles (D) have an outer shell part and a core part,
The core portion includes at least one of a conjugated diene rubber containing a structural unit derived from a conjugated diene and a silicone rubber,
The outer shell portion includes a polymer having a methyl methacrylate structure, a styrene structure, an acrylonitrile structure, and a glycidyl structure.
Photothermosetting resin composition. The core portion includes a conjugated diene rubber containing a structural unit derived from a conjugated diene and an aromatic vinyl compound.
The photothermosetting resin composition according to claim 1. further containing an inorganic filler (E),
The photothermosetting resin composition according to claim 1 or 2. The content of the organic fine particles (D) is 5 to 17% by mass,
The photothermosetting resin composition according to any one of claims 1 to 3. The latent thermosetting agent (C) is one or more curing agents selected from the group consisting of an organic acid dihydrazide-based thermal latent curing agent, an amine adduct-based thermal latent curing agent, and a polyamine-based thermal latent curing agent. be,
The photothermosetting resin composition according to any one of claims 1 to 4. Comprising the photothermosetting resin composition according to any one of claims 1 to 5,
LCD sealant. A step of applying the liquid crystal sealant according to claim 6 on the alignment film of one of a pair of substrates each having an alignment film to form a seal pattern;
Dropping liquid crystal onto the one substrate and within the area of the seal pattern, or onto the other substrate while the seal pattern is uncured;
overlapping the one substrate and the other substrate via the seal pattern;
curing the seal pattern;
including,
A method for manufacturing a liquid crystal display panel. In the step of curing the seal pattern, curing the seal pattern by irradiating the seal pattern with light,
The method for manufacturing a liquid crystal display panel according to claim 7. The light irradiated to the seal pattern includes light in the visible light region.
The method for manufacturing a liquid crystal display panel according to claim 8. In the step of curing the seal pattern, further heating the seal pattern after being irradiated with light;
The method for manufacturing a liquid crystal display panel according to claim 8 or 9. a pair of substrates each having an alignment film;
a frame-shaped sealing member disposed between the alignment films of the pair of substrates;
a liquid crystal layer filled in a space surrounded by the sealing member between the pair of substrates,
The sealing member is a cured product of the liquid crystal sealant according to claim 6,
LCD display panel.