TWI723102B - Display element sealant, liquid crystal display panel and manufacturing method thereof - Google Patents

Abstract

The object of the present invention is to provide a photocurable resin composition that has sufficient curability to visible light and can highly suppress contamination of liquid crystals when used as, for example, a display element sealing agent, particularly a liquid crystal display element sealing agent. The photocurable resin composition of the present invention contains a curable compound A having an ethylenically unsaturated double bond in the molecule, and a compound B represented by the following general formula (1).

(In the general formula (1), _{at least one of R 1} to R ₈ is -SX, X and at least one of the remaining R ₁ to R ₈ is a hydroxyl group, and the number of carbons 1 to 8 substituted by a hydroxyl group or a hydroxyl group-containing group The alkyl group, an alkenyl group with 1 to 8 carbon atoms substituted by a hydroxyl group or a hydroxyl group-containing group, or an aryl group substituted by a hydroxyl group or a hydroxyl group-containing group)

Description

Display element sealant, liquid crystal display panel and manufacturing method thereof law

The present invention relates to a photocurable resin composition, a display element sealing compound, a liquid crystal display element sealing compound, a liquid crystal display panel, and a manufacturing method thereof.

In recent years, as image display panels for various electronic devices represented by mobile phones and personal computers, display panels such as liquid crystal or organic electroluminescence (EL) have been widely used. For example, a liquid crystal display panel has two transparent substrates provided with electrodes on the surface, a frame-shaped sealing member sandwiched between the transparent substrates, and liquid crystal sealed in an area surrounded by the sealing member.

The liquid crystal display panel can be manufactured by, for example, a liquid crystal dropping process. Regarding the manufacture of a liquid crystal display panel using a liquid crystal dropping process, it is carried out in the following manner: (1) apply a liquid crystal display element sealant to the inner edge of a transparent substrate to form a frame for filling the liquid crystal, and (2) apply the frame to the frame. Liquid crystal is dripped inside, (3) after keeping the liquid crystal display element sealant in an uncured state and superimposing the two substrates under high vacuum, (4) hardening the liquid crystal display element sealant.

In this way, in the liquid crystal dropping process, photocuring or thermal curing is performed in a state where the uncured liquid crystal display element sealing compound is in contact with the liquid crystal. Therefore, the sealant for liquid crystal display elements is required not only to have high curability, but also to reduce the liquid crystal Pollution.

As the liquid crystal display element sealing agent used in the liquid crystal dropping process, the following photocurable resin composition containing a compound having a (meth)acryloyl group in the molecule and as a photopolymerization initiator has been proposed Anthraquinone derivatives (for example, Patent Document 1). In addition, a photocurable resin composition has been proposed which contains a photopolymerizable oligomer and a photopolymerization initiator obtained by reacting a compound having two or more epoxy groups in the molecule with hydroxythioxanthone Compound B (for example, Patent Document 2). Furthermore, a sealing compound for liquid crystal display elements containing a curable resin, a specific thioxanthone-based polymerization initiator, and an amine-based sensitizer has been proposed (for example, Patent Document 3).

Prior art literature

Patent literature

Patent Document 1: International Publication No. 2007/074782

Patent Document 2: International Publication No. 2012/077720

Patent Document 3: International Publication No. 2015/072415

However, the photopolymerization initiator having a thioxanthone skeleton of Patent Document 2 and Patent Document 3 has a low sensitivity to visible light, and therefore, a composition containing the same has a problem of insufficient curability.

On the other hand, the photopolymerization initiator having an anthraquinone skeleton of Patent Document 1 has high sensitivity to visible light, and therefore the composition containing it has sufficient curability. however, Since the photopolymerization initiator having an anthraquinone skeleton has high sensitivity to visible light, there is a concern that the photopolymerization initiator eluted under light irradiation reacts with the liquid crystal to generate a polymer component. Such a polymer component easily contaminates the liquid crystal together with the eluted photopolymerization initiator, resulting in display failure.

The present invention has been made in view of the above-mentioned problems, and its object is to provide a photocurable resin composition that is also resistant to visible light when used as, for example, a display element sealing agent, particularly a liquid crystal display element sealing agent. It has sufficient curability and can highly suppress the contamination of liquid crystals.

[1] A photocurable resin composition containing a curable compound A having an ethylenically unsaturated double bond in the molecule, and a compound B represented by the following general formula (1),

(In the general formula (1), _{at least one of R 1} to R ₈ is -SX (X is an optionally substituted alkyl group with 1 to 8 carbons, an optionally substituted alkenyl group with 1 to 8 carbons, or Substituted aryl group), the remaining R ₁ to R ₈ are hydrogen atoms, hydroxyl groups, optionally substituted alkyl groups with 1 to 8 carbons, optionally substituted alkenyl groups with 1 to 8 carbons, or A substituted aryl group, and _{at least one of the X and the remaining R 1} to R ₈ is a hydroxyl group, an alkyl group with 1 to 8 carbon atoms substituted by a hydroxyl group or a hydroxyl group-containing group, a hydroxyl group or a hydroxyl group-containing group Alkenyl groups with 1 to 8 carbon atoms, or aryl groups substituted with hydroxyl groups or hydroxyl-containing groups).

[2] The photocurable resin composition according to [1], wherein the compound B is represented by the following general formula (2),

(In the general formula (2), X is an alkyl group with 1 to 8 carbons substituted by a hydroxyl group or a hydroxyl-containing group, an alkenyl group with 1 to 8 carbons substituted by a hydroxyl group or a hydroxyl-containing group, or Aryl group substituted by a hydroxyl group or a hydroxyl group-containing group).

[3] The photocurable resin composition as described in [1] or [2], wherein the compound B is represented by the following general formula (2'),

(In the general formula (2'), X is an alkyl group with 1 to 8 carbons substituted with a hydroxyl group or a hydroxyl group-containing group, an alkenyl group with 1 to 8 carbons substituted with a hydroxyl group or a hydroxyl group-containing group, or Aryl substituted with a hydroxyl group or a hydroxyl group-containing group).

[4] The photocurable resin composition as described in any one of [1] to [3], further containing an amine-based sensitizer C.

[5] The photocurable resin composition according to any one of [1] to [4], wherein the content of the compound B relative to the curable compound A is 0.01% by mass to 10% by mass.

[6] The photocurable resin composition according to any one of [1] to [5], wherein the curable compound A further has an epoxy group in the molecule.

[7] The photocurable resin composition according to any one of [1] to [6], further containing a thermosetting compound D having an epoxy group in the molecule (wherein, the thermosetting compound D is It is set to be different from the curable compound A) and the thermosetting agent E.

[8] The photocurable resin composition according to [7], wherein the thermosetting agent E is selected from the group consisting of organic acid dihydrazine-based thermal latent curing agents, imidazole-based thermal latent curing agents, and amine adducts. One or more of the group consisting of a material-based thermal latent curing agent and a polyamine-based thermal latent curing agent.

[9] The photocurable resin composition according to any one of [1] to [8], further containing an inorganic filler or an organic filler.

[10] A display element sealing agent comprising the photocurable resin composition as described in any one of [1] to [9].

[11] A liquid crystal display element sealing agent comprising as described in any one of [1] to [9] The photocurable resin composition described.

[12] A method of manufacturing a liquid crystal display panel, including the steps of: using the liquid crystal display element sealant as described in [11] to form a sealing pattern on a substrate; Injecting liquid crystal in the area of the sealing pattern or on another substrate paired with the one substrate; superimposing the one substrate and the other substrate with the sealing pattern interposed therebetween; and making the sealing pattern hardening.

[13] The method for manufacturing a liquid crystal display panel according to [12], wherein the step of hardening the seal pattern includes a step of irradiating the seal pattern with light to harden the seal pattern.

[14] The method for manufacturing a liquid crystal display panel as described in [13], wherein the light irradiated to the seal pattern includes light in the visible light region.

[15] The method of manufacturing a liquid crystal display panel as described in [13] or [14], wherein the step of hardening the seal pattern further includes a step of heating and hardening the seal pattern irradiated with light.

[16] A liquid crystal display panel comprising a pair of substrates, a frame-shaped sealing member arranged between the pair of substrates, and a space enclosed by the sealing member between the pair of substrates The liquid crystal layer of, and the sealing member is a cured product of the liquid crystal display element sealing agent as described in [11].

According to the present invention, it is possible to provide a device having sufficient curability to visible light when used as, for example, a sealing agent for a display element, particularly a sealing agent for a liquid crystal display element, In addition, a photocurable resin composition capable of highly suppressing contamination of liquid crystals.

1. Light-curable resin composition

The photocurable resin composition of the present invention contains a curable compound A and a compound B, and may further contain an amine-based sensitizer C, a thermosetting compound D, and a thermosetting agent E as necessary. The photocurable resin composition of the present invention may further contain other components as necessary.

1-1. Hardening compound A

The curable compound A contained in the photocurable resin composition of the present invention is a compound having an ethylenically unsaturated double bond in the molecule. The compound having an ethylenically unsaturated double bond in the molecule is preferably a compound having a (meth)acryloyl group in the molecule. The number of (meth)acryloyl groups per molecule is one or two or more. The compound having a (meth)acryloyl group in the molecule may be any of monomers, oligomers, and polymers. (Meth)acryloyl refers to acrylic or methacryloyl, and (meth)acrylate refers to acrylate or methacrylate.

Examples of compounds having one (meth)acryloyl group in one molecule include: methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, etc. (meth) Alkyl acrylate.

Examples of compounds having two or more (meth)acrylic groups in one molecule include di(meth)acrylates such as polyethylene glycol, propylene glycol, and polypropylene glycol; Di(meth)acrylate of tris(2-hydroxyethyl) isocyanurate; diol obtained by adding 4 mols of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol Di(meth)acrylate of diol; added 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A; di(meth)acrylate of diol obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A; Di(meth)acrylate or tri(meth)acrylate of triol obtained by adding more than 3 moles of ethylene oxide or propylene oxide to methyl propane; add to 1 mole of bisphenol A Di(meth)acrylate of diol derived from 4 moles of ethylene oxide or propylene oxide; tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate; trimethylol Propyl propane tri(meth)acrylate or its oligomer; pentaerythritol tri(meth)acrylate or its oligomer; poly(meth)acrylate of dipentaerythritol; tris(acryloxy) isocyanurate Ethyl) ester; caprolactone modified tris(acryloxyethyl) isocyanurate; caprolactone modified tris(methacryloxyethyl) isocyanurate; alkyl modified Dipentaerythritol polyacrylate or polymethacrylate; Caprolactone modified polyacrylate or polymethacrylate of dipentaerythritol; Hydroxytrimethylacetate neopentyl glycol diacrylate or hydroxytrimethylacetic acid Neopentyl glycol dimethacrylate; caprolactone modified hydroxytrimethyl acetate neopentyl glycol di(meth)acrylate; ethylene oxide modified phosphoric acid acrylate or ethylene oxide modified phosphate diphosphate Methacrylate; Ethylene oxide modified alkylated phosphoric acid (meth)acrylate; Neopentyl glycol, trimethylolpropane, pentaerythritol oligomeric (meth)acrylate, etc.

The curable compound A may further have an epoxy group in the molecule. The number of epoxy groups per molecule is one or two or more. If the curable compound A has not only a (meth)acryloyl group but also an epoxy group in the molecule, the photocurable resin composition containing the curable compound A can be imparted with photocuring properties and thermosetting properties. borrow Therefore, the hardenability of the hardened product can be improved.

The compound having a (meth)acryloyl group and an epoxy group in the molecule may be, for example, glycidyl (meth)acrylate obtained by reacting an epoxy compound and (meth)acrylic acid in the presence of a basic catalyst.

The epoxy compound to be reacted may be a polyfunctional epoxy compound having two or more epoxy groups in the molecule, and the crosslink density is prevented from being too high and the adhesiveness of the cured photocurable resin composition is prevented from decreasing. In other words, it is preferably a bifunctional epoxy compound. Examples of bifunctional epoxy compounds include: bisphenol type epoxy compounds (bisphenol A type, bisphenol F type, 2,2'-diallyl bisphenol A type, bisphenol AD type, and hydrogenated bisphenol Type, etc.), biphenyl type epoxy compound and naphthalene type epoxy compound. Among them, from the viewpoint of good coating properties, bisphenol A type and bisphenol F type bisphenol epoxy compounds are preferred. Bisphenol-type epoxy compounds have advantages such as superior coating properties compared to diphenyl ether-type epoxy compounds.

The compound having a (meth)acryloyl group and an epoxy group in the molecule may be one type or a combination of two or more types.

You may combine the compound A1 which has a (meth)acryloyl group in a molecule|numerator and does not have an epoxy group, and the compound A2 which has a (meth)acryloyl group and an epoxy group in a molecule|numerator. With this, when the photocurable resin composition further contains an epoxy compound as the thermosetting compound D, the epoxy compound and the compound having a (meth)acrylic group in the molecule and not having an epoxy group can be improved. Compatibility of A1. In addition, the photocurable resin composition contains the compound B having moderate hydrophilicity. Therefore, even if it contains the compound A1, which is more hydrophobic than the compound A2, the photocurable resin can be suppressed. The elution of the lipid composition into the display element, especially the liquid crystal. The content mass ratio of the compound A2 and the compound A1 can be set to, for example, A2/A1=1/0.4 to 1/0.6.

The content of the compound A2 having a (meth)acryloyl group and an epoxy group in the molecule is not particularly limited. For example, it may be 30% by mass or more with respect to the total of the curable compound A.

The weight average molecular weight of the curable compound A is preferably about 310 to 1,000. The weight average molecular weight of the curable compound A can be measured by polystyrene conversion using, for example, Gel Permeation Chromatography (GPC).

The content of the curable compound A is preferably 40% by mass to 80% by mass, and more preferably 50% by mass to 75% by mass relative to the photocurable resin composition.

1-2. Compound B

The compound B contained in the photocurable resin composition of the present invention can function as a photoinitiator, and is represented by the following general formula (1).

At least one _{of R 1} to R ₈ in the general formula (1) is -SX. X is an optionally substituted alkyl group having 1 to 8 carbons, an optionally substituted alkenyl group having 1 to 8 carbons, or an optionally substituted aryl group. The remaining R ₁ to R ₈ are a hydrogen atom, a hydroxyl group, an optionally substituted alkyl group having 1 to 8 carbon atoms, an optionally substituted alkenyl group having 1 to 8 carbon atoms, or an optionally substituted aryl group.

Among them, _{at least one of R 1} to R ₈ is a hydroxyl group or a hydroxyl group-containing group. That is, at least one of X and the remaining R ₁ to R ₈ is a hydroxyl group, an alkyl group having 1 to 8 carbons substituted with a hydroxyl group or a hydroxyl group-containing group, and a carbon number of 1 to 1 substituted with a hydroxyl group or a hydroxyl group-containing group. The alkenyl group of 8 or the aryl group substituted with a hydroxyl group or a hydroxyl group-containing group. The number of hydroxyl groups in the hydroxyl group-containing group may be one or two or more.

Examples of the alkyl group having 1 to 8 carbon atoms represented by X or the remaining R ₁ to R ₈ include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl. The alkyl group having 1 to 8 carbon atoms may be linear or branched.

Examples of the alkenyl group having 1 to 8 carbons represented by X or the remaining R ₁ to R _{8 include a propenyl group and a butenyl group.} The alkenyl group having 1 to 8 carbon atoms may be straight or branched.

Examples of substituents that an alkyl group and an alkenyl group may have include a hydroxyl group, a hydroxyl group-containing group, and an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms (for example, a methoxy group, etc.). Examples of alkyl groups with 1 to 8 carbon atoms substituted with hydroxyl groups or hydroxyl groups include: hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, -CH ₂ -O-CH ₂ CH(OH )-CH ₂ -O-CO-C(CH ₃ )=CH etc. Examples of the alkenyl group having 1 to 8 carbon atoms substituted with a hydroxyl group or a hydroxyl group-containing group include a hydroxybutenyl group and the like.

Examples of the aryl group represented by X or the remaining R ₁ to R ₈ include a phenyl group, a naphthyl group, and the like. Examples of substituents that the aryl group may have include: hydroxyl groups, hydroxyl-containing groups, and alkyl groups having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms (e.g., methyl, ethyl, perfluoromethyl, etc.) ), an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms (e.g., methoxy group, etc.), and the like. The number of substituents is not particularly limited, but one to three is preferred. Examples of aryl groups substituted with a hydroxyl group or a hydroxyl group-containing group include: hydroxyphenyl, dihydroxyphenyl, -C ₆ H ₄ -O-CH ₂ CH(OH)-CH ₂ -O-CO-C( CH ₃ )=CH etc.

The hydroxyl group-containing group is preferably a group formed by ring-opening addition of a substituted alkylene oxide to the hydroxyl group. Examples of the substituent in the alkylene oxide which may be substituted include a polymerizable functional group. The polymerizable functional group is a photopolymerizable functional group (for example, (meth)acrylic acid group) or a thermally polymerizable functional group (for example, oxepanyl group). Since the compound B having a polymerizable functional group can undergo a polymerization reaction with the curable compound A, it is considered that it is easy to suppress elution from the cured product. Examples of the hydroxyl group-containing group having a polymerizable functional group include a group represented by the following formula (A).

Y: alkylene or phenylene

Z: alkylene

Rb: alkyl

The compound B has a hydroxyl group in the molecule, and may not further have another hydrophilic group (for example, an NHCO group) in terms of suppressing liquid crystal contamination well.

In terms of high light absorption in the visible light region, Compound B is better than It is preferably represented by the following general formula (2), and more preferably represented by the following general formula (2').

X in the general formula (2) and general formula (2') is the above-mentioned alkyl group with 1 to 8 carbons substituted by a hydroxyl group or a hydroxyl group-containing group, a carbon substituted by a hydroxyl group or a hydroxyl group-containing group An alkenyl group of 1 to 8 or an aryl group substituted with a hydroxyl group or a hydroxyl group-containing group.

Specific examples of the compound represented by the general formula (1) include: 2-(2-hydroxyethylthio)thioxanthone, 2-(2-hydroxypropylthio)thioxanthone, 2-(4-hydroxybenzene) Sulfuryl) thioxanthone and the like.

The compound represented by the general formula (1) can be produced by any method. For example, a compound having a thiol group and a hydroxyl group can be reacted with a halogenated thioxanthone; the substituted alkylene oxide can be further subjected to a ring-opening addition reaction with the compound obtained by the reaction. In addition, a compound having a thiol group may be reacted with halogenated hydroxythioxanthone.

For example, the compound represented by general formula (2) and general formula (2') can be obtained by reacting a compound having a thiol group and a hydroxyl group with a halogenated thioxanthone (refer to the following reaction formula 1); The alkylene oxides that can be substituted are further reacted with The compound of is obtained by the ring-opening addition reaction (refer to the following reaction formula 2).

In the reaction formula 1, Y is an aryl group, an alkylene group having 1 to 8 carbons, or an alkenylene group having 1 to 8 carbons. The so-called "Halo" refers to a halogen atom such as a chlorine atom.

In the reaction formula 2, Y is an arylene group, an alkylene group or an alkenylene group. Ra is a hydrogen atom, an alkyl group, or a group represented by the following formula (B). Z and Rb of the following formula (B) are the same as Z and Rb of the above-mentioned formula (A), respectively.

The original thioxanthone skeleton itself has low sensitivity to visible light. In contrast, the compound B has a structure in which a thioether group is bonded to the thioxanthone skeleton, so that the sensitivity to visible light can be appropriately improved.

Compound B further has a hydroxyl group as a hydrophilic group in the molecule. Therefore, not only can the elution into the liquid crystal exhibiting hydrophobicity be reduced, but also when the photocurable resin composition is cured, the compound B and other components (for example, monomer components) can form chemical bonds such as hydrogen bonds or addition bonds. Therefore, the elution of the compound B or its decomposition product from the obtained hardened product can be reduced.

The number of hydroxyl groups in one molecule of the compound B is preferably one to five, and more preferably one to three. If the number of hydroxyl groups in a molecule is one or more, the hydrophilicity of compound B can be appropriately increased, and the photocurable resin composition can be used as a liquid crystal display element sealing agent to preferably suppress the compound B in the liquid crystal Dissolve. If the number of hydroxyl groups in one molecule is five or less, the moisture resistance of the cured product is unlikely to be impaired.

The molecular weight of compound B is preferably 274 to 500, for example. If the molecular weight of the compound B is 274 or more, elution into the liquid crystal is unlikely to occur. If the molecular weight of the compound B is 500 or less, the compatibility with the curable compound A can be improved, so sufficient curability can be easily obtained. The molecular weight of compound B is more preferably 280-350.

The molecular weight of compound B can be obtained in the form of the "relative molecular mass" of the molecular structure of the main peak detected when performing High Performance Liquid Chromatography (HPLC) under the following conditions .

Specifically, the compound B was dissolved in tetrahydrofuran (Tetrahydrofuran, THF) to prepare a sample solution, and a high performance liquid chromatography (HPLC) measurement was performed under the following measurement conditions. Then, the area percentage of the detected peaks (the ratio of the area of each peak to the total area of all peaks) is determined, and the presence or absence of a main peak (main detection peak) is confirmed. The "main peak (main detection peak)" refers to the peak with the highest intensity (the peak with the highest peak height) among all peaks detected at a detection wavelength of 400 nm.

(HPLC measurement conditions)

Device: AcquityTM UPLC H-Class system manufactured by Waters

Column: Acquity UPLC BEH C18, 2.1mm ID×100mm Particle size: 1.7μm

Mobile phase: A: Acetonitrile

B: 5mM ammonium acetate aqueous solution

A/B=60/40 (0 minutes~4 minutes)

95/5 (4 minutes to 9 minutes)

95/5 (9 minutes to 10 minutes)

Flow rate: 0.4mL/min

Photo-Diode Array (PDA) detector: measurement wavelength: 190nm~500nm, selected wavelength: 400nm

The relative molecular mass corresponding to the peak apex of the detected main peak can be analyzed by liquid chromatography mass spectrometry (Liquid Chromatography-Mass Spectrometry, LC/MS).

(LC/MS measurement conditions)

Device: manufactured by Waters, AcquityTM H-Class system/SQ Detector

Column: Acquity UPLC BEH C18, 2.1mm ID×100mm Particle size: 1.7μm

Mobile phase: A: Acetonitrile

B: 5mM ammonium acetate aqueous solution

A/B=60/40 (0 minutes~4 minutes)

95/5 (4 minutes to 9 minutes)

95/5 (9 minutes~10 minutes)

Flow rate: 0.4mL/min

Ionization: Electrospray Ionization (Electrospray Ionization, ESI), positive/negative ion measurement

PDA detector: measurement wavelength: 190nm~500nm, select wavelength: 400nm

Compound B may be one type or a combination of two or more types.

The content of the compound B relative to the curable compound A is preferably 0.01% by mass to 10% by mass. If the content of the compound B is 0.01% by mass or more, it is easy to obtain sufficient photocurability. If the content of the compound B is 10% by mass or less, the elution into the liquid crystal is small, and therefore the contamination of the liquid crystal is more easily reduced. Relative to the curable compound A, the content of the compound B is more preferably 0.1% by mass to 5% by mass, still more preferably 0.1% by mass to 3% by mass, and particularly preferably 0.1% by mass to 2.5% by mass.

The structure of compound B contained in the photocurable resin composition can be measured by high performance liquid chromatography (HPLC), liquid chromatography mass spectrometry (LC/MS) and nuclear magnetic resonance (Nuclear Magnetic Resonance, NMR) or infrared rays. (Infrared, IR) Determined by measuring the combination. Specifically, it can be performed in the following procedure.

1) Centrifugal separation of the solution obtained by dissolving the photocurable resin composition in tetrahydrofuran (THF) with a centrifugal separator to settle particle components such as silica particles or thermoplastic resin particles. The obtained solution was filtered with a filter to remove particle components, and a sample liquid was obtained.

2) Perform high performance liquid chromatography (HPLC) measurement on the sample solution obtained in 1). The HPLC measurement method and conditions are the same as the HPLC measurement method and conditions in the measurement of the molecular weight of Compound B.

Then, in the HPLC measurement, liquid chromatography mass spectrometry (LC/MS) was used to measure the thioxanthone skeleton corresponding to the peak apex of the main peak detected by the characteristic wavelength 400nm detector. Molecular mass and composition formula. The LC/MS measurement method and conditions are the same as the LC/MS measurement method and conditions in the measurement of the molecular weight of Compound B.

3) Perform NMR measurement or IR measurement on the sample liquid obtained in 1). In this way, the presence or absence of the characteristic spectrum of the thioxanthone skeleton, thioether group, and hydroxyl group is confirmed, and the chemical structure is determined.

As described above, from the viewpoint of obtaining high curability, the photoinitiator preferably has a high sensitivity to visible light. On the other hand, if the photoinitiator is too sensitive to visible light, the eluted photoinitiator may react unnecessarily with the liquid crystal.

In contrast, the compound B that can function as a photoinitiator has a structure in which a thioether group is bonded to the thioxanthone skeleton, and therefore has a moderate sensitivity to visible light (the sensitivity is not too high). Therefore, it has good curability in the visible light region, and can suppress unwanted reactions with the liquid crystal when eluted into the liquid crystal.

Furthermore, since compound B has a hydrophilic hydroxyl group, it can also reduce elution into hydrophobic liquid crystals.

Thereby, it is possible to highly suppress the contamination of the liquid crystal caused by the elution of the compound B into the liquid crystal or the unwanted reaction with the liquid crystal, without impairing the curability in the visible light region.

1-3. Amine-based sensitizer C

Amine-based sensitizer C includes alkylamine compounds, amine-modified (meth)acrylate compounds, having an aminobenzyl structure (-R ₁ R ₂ NC ₆ H ₄ -CO-, R ₁ and R ₂ ：Hydrogen atom or alkyl) compound, etc.

Examples of alkylamine compounds include: n-butylamine, di-n-butylamine, tri-n-butylphosphine, allylthiouric acid, triethylamine, diethylaminoethyl methacrylate, diethanolamine Wait.

Examples of amine-modified (meth)acrylate compounds include: amine-modified polyester (meth)acrylate oligomers, amine-modified epoxy (meth)acrylate oligomers, amine-modified (meth)acrylate oligomers, and amine-modified (meth)acrylate oligomers. Base) acrylate monomers and the like.

Examples of compounds having an aminobenzyl structure include: 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone Benzophenone compounds with amino groups; 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid Methyl ester, ethyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4-dimethylamine Benzoic acid or esters thereof having an amino group such as butoxyethyl benzoate and 2-(dimethylamino)ethyl benzoate; and a compound represented by the following general formula (3).

P in the general formula (3) is a group derived from a polyol compound. Examples of polyol compounds include: (poly)ethylene glycol, (poly)propylene glycol, (poly)butylene glycol, glycerin, trimethylolpropane, di-trimethylolpropane, pentaerythritol, dipentaerythritol, and hexamethylene glycol. Ester polyol. The molecular weight of the group represented by P is preferably 100 to 2,000. If the molecular weight of the group represented by P is 100 or more, elution into the liquid crystal is less likely to occur, and if it is 2000 or less, it is possible to suppress an excessive increase in the viscosity of the photocurable resin composition.

N in the general formula (3) represents an integer of 1 or more, preferably an integer of 2-6. If n is 2 or more, the molecular weight can be made constant or more, so it is easy to suppress elution into the liquid crystal. If n is 6 or less, it is easy to suppress an excessive increase in the viscosity of the photocurable resin composition.

The compound represented by the general formula (3) is preferably n is 2, and P is composed of polyethylene A group derived from a diol.

Among these compounds, in terms of improving the reactivity of Compound B, compounds having an aminobenzyl structure are preferred. In addition, the compound having an aminobenzyl structure may not further have an NHCO group.

The molecular weight of the sensitizer C is preferably 200 or more and 3000 or less, for example. If the molecular weight of the sensitizer C is 200 or more, it is unlikely to be eluted into the liquid crystal, so it is easy to reduce the contamination of the liquid crystal. If the molecular weight of the sensitizer C is 3000 or less, the compatibility with the curable compound A is unlikely to be impaired. The molecular weight of the sensitizer C is more preferably 250 or more and 1,000 or less.

The content of the sensitizer C is preferably 0.01% by mass to 10% by mass relative to the curable compound A. If the content of the sensitizer C is 0.01% by mass or more, the compound B can be sufficiently activated, and therefore sufficient curability can be easily obtained. If the content of the sensitizer C is 10% by mass or less, the curability will not be impaired, and elution into the liquid crystal will not easily occur. Relative to the curable compound A, the content of the sensitizer C is more preferably 0.1% by mass to 5% by mass, still more preferably 0.1% by mass to 3% by mass, and particularly preferably 0.1% by mass or more and less than 2% by mass.

The better content of compound B and sensitizer C is compound B: sensitizer C=1:0.05~1:5. If the content mass ratio of the compound B and the sensitizer C is within the above-mentioned range, it is easy to obtain sufficient curability even under long-wavelength light. The content ratio of compound B to sensitizer C is more preferably compound B: sensitizer C=1:0.1~1:2.

1-4. Thermosetting compound D

The thermosetting compound D is preferably an epoxy compound having an epoxy group in the molecule. Among them, the thermosetting compound D is set to be different from the curable compound A. The thermosetting compound D is more preferably an epoxy compound having no (meth)acryloyl group in the molecule. The epoxy compound may be any of monomers, oligomers, or polymers. When the photocurable resin composition is used as a sealing agent for liquid crystal display elements, for example, the solubility or diffusibility of the epoxy compound in the liquid crystal is low, which not only improves the display characteristics of the obtained liquid crystal panel, but also improves the durability of the cured product. Wetness.

The epoxy compound may be an aromatic epoxy compound having a weight average molecular weight of 500 to 10,000, preferably 1,000 to 5,000. The weight average molecular weight of the epoxy compound can be measured by polystyrene conversion using gel permeation chromatography (GPC).

Examples of aromatic epoxy compounds include: aromatic polyglycidyl ether compounds, which use aromatic diols represented by bisphenol A, bisphenol S, bisphenol F, bisphenol AD, etc., and these two Alcohol is obtained by reacting diols modified from ethylene glycol, propylene glycol, and alkanediol with epichlorohydrin; novolac type polyglycidyl ether compound, which is derived from phenol or cresol and formaldehyde Polyphenols represented by novolak resins, polyalkenyl phenols or their copolymers are obtained by the reaction of epichlorohydrin; glycidyl ether compounds of xylylene phenol resins, etc. Among them, preferred are cresol novolac type epoxy compounds, phenol novolac type epoxy compounds, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, triphenol methane type epoxy compounds, and triphenol ethane. Type epoxy compound, triphenol type epoxy compound, dicyclopentadiene type epoxy compound, diphenyl ether type epoxy compound and biphenyl type epoxy compound. The epoxy compound may be one type or a combination of two or more types.

The epoxy compound may be liquid or solid. In terms of easily improving the moisture resistance of the cured product, a solid epoxy compound is preferred. The softening point of the solid epoxy compound is preferably 40°C or more and 150°C or less.

The content of the thermosetting compound D is preferably 3% by mass to 20% by mass relative to the photocurable resin composition. If the content of the thermosetting compound D is 3% by mass or more, the moisture resistance of the cured product of the photocurable resin composition is easily improved. If the content of the thermosetting compound D is 20% by mass or less, an excessive increase in the viscosity of the photocurable resin composition can be suppressed. The content of the thermosetting compound D is more preferably 3% by mass to 15% by mass, and still more preferably 5% by mass to 15% by mass relative to the photocurable resin composition.

1-5. Thermal hardener E

The thermosetting agent E is a compound that does not harden the thermosetting compound D under normal storage conditions (room temperature, under visible light, etc.), but hardens the compound when heat is applied. The photocurable resin composition containing the thermosetting agent E is excellent in storage stability and excellent in thermosetting properties. The thermal hardener E is preferably an epoxy hardener.

Regarding the melting point of the epoxy curing agent, from the viewpoint of improving the viscosity stability of the photocurable resin composition without impairing the moisture resistance of the cured product, although it also depends on the thermal curing temperature, it is preferably 50°C. Above and 250°C or less, more preferably 100°C or more and 200°C or less, and still more preferably 150°C or more and 200°C or less.

Examples of epoxy hardeners include organic acid dihydrazide-based thermal latent hardeners, imidazole-based thermal latent hardeners, amine adduct-based thermal latent hardeners, and polyamine-based thermal latent hardeners.

Examples of organic acid dihydrazine-based thermal latent hardeners include: dihydrazine adipate (melting point 181°C), 1,3-bis(hydrazinocarbonylethyl)-5-isopropylhydantoin (Melting point 120℃), 7,11-octadecadiene-1,18-dicarbohydrazine (melting point 160℃), dihydrazine dodecanedioate (melting point 190℃), and dihydrazine sebacate (Melting point 189°C) and so on. Examples of imidazole-based thermal latent hardeners include 2,4-diamino-6-[2'-ethylimidazolyl-(1')]-ethyltriazine (melting point 215°C to 225°C), and 2-Phenylimidazole (melting point 137℃~147℃) and so on. The amine adduct-based thermal latent curing agent is a thermally latent curing agent containing an addition compound obtained by reacting an amine-based compound with a catalyst activity with an arbitrary compound, and examples thereof include: Ajinomoto Precision Technology (Ajinomoto Amicure PN-40 (melting point 110°C) manufactured by Fine-techno (stock), and Amicure PN-23 manufactured by Ajinomoto Fine-techno (stock) Melting point 100°C), Amicure PN-31 (melting point 115°C) manufactured by Ajinomoto Fine-techno (stock), Ajinomoto Fine-techno (stock) Amicure PN-H (melting point 115°C) manufactured by Ajinomoto Fine-techno (stock), Amicure MY-24 (melting point 120°C) manufactured by Ajinomoto Fine-techno, and flavor Amicure MY-H (melting point 131°C) manufactured by Ajinomoto Fine-techno (stock), etc. Polyamine-based thermal latent hardeners are thermal latent hardeners having a polymer structure obtained by reacting amines and epoxides, and examples thereof include: Adika hardener manufactured by ADEKA Co., Ltd. (Adeka Hardner) EH4339S (softening point 120℃~130℃), and Adeka Hardner EH4357S (softening point) manufactured by ADEKA (stock) 73℃~83℃) and so on. The epoxy hardener may be only one type or a combination of two or more types.

With respect to the photocurable resin composition, the content of the thermosetting agent E is preferably 3% by mass to 30% by mass, more preferably 3% by mass to 20% by mass, and still more preferably 5% by mass to 20% by mass. The photocurable resin composition containing the thermosetting agent E can be a one-liquid curable resin composition. The one-component curable resin composition does not need to mix the main agent and the curing agent during use, so it has excellent workability.

With respect to the photocurable resin composition, the total content of the thermosetting compound D and the thermosetting agent E is preferably 6 mass% to 50 mass %, more preferably 6 mass% to 35 mass %, and still more preferably 6 mass% ~30% by mass.

1-6. Other ingredients F

1-6-1. Thermoplastic resin particles

The photocurable resin composition of the present invention may further contain thermoplastic resin particles as necessary. The thermoplastic resin particles include a thermoplastic resin with a softening point temperature of 50°C to 120°C, preferably 70°C to 100°C, as determined by the ring and ball method, and the number average particle size may be 0.05 μm to 5 μm, preferably 0.1 μm~3μm. The photocurable resin composition containing such thermoplastic resin particles can relax the shrinkage stress generated in the cured product. In addition, by setting the number average particle diameter to the upper limit or less, when forming a sealing member with a narrow line width, thermoplastic resin particles can be used to prevent a decrease in coating stability. The number average particle size can be measured with a dry particle size distribution meter.

Examples of the thermoplastic resin particles include fine particles obtained by suspension polymerization of a resin containing an epoxy group and a double bond group and a monomer capable of radical polymerization. Examples of resins containing epoxy groups and double bond groups include resins obtained by reacting bisphenol F type epoxy resin and methacrylic acid in the presence of tertiary amine. Examples of monomers that can be radically polymerized include butyl acrylate, glycidyl methacrylate, and divinylbenzene.

The content of the thermoplastic resin particles relative to the photocurable resin composition is preferably 5% by mass to 40% by mass, more preferably 7% by mass to 30% by mass. When the content of the thermoplastic resin particles is within the above range, the thermoplastic resin particles can preferably relax the shrinkage stress during heat curing of the photocurable resin composition, and it is easy to form a sealing member with a target line width.

1-6-2. Filling agent

The photocurable resin composition of the present invention may further contain a filler as necessary. The photocurable resin composition containing the filler can improve the viscosity, the strength of the cured product, and the linear expansion properties.

The filler may be an inorganic filler or an organic filler. Examples of inorganic fillers 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 , Potassium titanate, kaolin, talc, glass beads, sericite, activated clay, bentonite, aluminum nitride, silicon nitride, etc. Among them, silica and talc are preferred.

The shape of the filler may be a fixed shape such as a spherical shape, a plate shape, or a needle shape, or an indefinite shape. When the filler is spherical, the average primary particle size of the filler is preferably 1.5 μm or less, and the specific surface area is preferably 0.5 m ² /g to 20 m ² /g. The average primary particle size of the filler can be measured by the laser diffraction method described in Japanese Industrial Standards (JIS) Z8825-1. The specific surface area of the filler can be measured by the Brunauer-Emmett-Tellern (BET) method described in JIS Z8830.

The content of the filler is preferably 1% by mass to 50% by mass relative to the photocurable resin composition. If the content of the filler is 50% by mass or less, the coating stability of the photocurable resin composition is less likely to be impaired. The content of the filler is more preferably 10% by mass to 30% by mass relative to the photocurable resin composition.

The photocurable resin composition of the present invention may further contain coupling agents such as thermal radical polymerization initiators, silane coupling agents, ion scavengers, ion exchangers, leveling agents, pigments, dyes, plasticizers, and disinfectants as needed. Additives such as foaming agents.

Examples of silane coupling agents include: vinyl trimethoxysilane, γ-(meth)acryloxypropyl trimethoxysilane, γ-glycidoxypropyl trimethoxysilane, γ-glycidoxysilane Group propyl triethoxy silane and so on. The content of the silane coupling agent may be 0.01% by mass to 5% by mass relative to the photocurable resin composition. If the content of the silane coupling agent is 0.01% by mass or more, the cured product of the photocurable resin composition tends to have sufficient adhesiveness.

The photocurable resin composition of the present invention may further include a spacer for adjusting the gap of the liquid crystal display panel.

1-7. Physical properties of photocurable resin composition

The viscosity of the E-type viscometer of the photocurable resin composition of the present invention at 25° C. and 2.5 rpm is preferably 200 Pa. s~450Pa. s, more preferably 300Pa. s~400Pa. s. If the viscosity is within the range, the dispenser for the use of the photocurable resin composition (dispenser) coatability becomes better.

The photocurable resin composition of the present invention can be used as a sealant, for example. The sealant is preferably a display element sealant for sealing display elements such as liquid crystal display elements, organic EL elements, and light emitting diode (Light Emitting Diode, LED) elements. The display element sealing compound is particularly preferably a liquid crystal display element sealing compound, and more preferably a liquid crystal display element sealing compound for a liquid crystal dropping process.

2. Display element panel and manufacturing method thereof

The display element panel of the present invention includes a pair of substrates, a display element arranged between the pair of substrates, and a sealing member that seals the display element. The sealing member can be a cured product of the display element sealing agent of the present invention. The display element sealing agent of the present invention contains the photocurable resin composition of the present invention.

Examples of display elements include liquid crystal display elements, organic EL elements, and LED elements. Among them, since the photocurable resin composition of the present invention can favorably suppress liquid crystal contamination, a liquid crystal display element is preferred.

That is, the liquid crystal display panel of the present invention includes a pair of substrates, a frame-shaped sealing member arranged between the pair of substrates, and a space enclosed by the frame-shaped sealing member between the pair of substrates. Liquid crystal layer (liquid crystal display element). The sealing member can be a cured product of the liquid crystal display element sealing agent of the present invention. The liquid crystal display element sealing agent of this invention contains the photocurable resin composition of this invention.

The pair of substrates are both transparent substrates. The material of the transparent substrate can be plastics such as glass or polycarbonate, polyethylene terephthalate, polyether ether, and polymethyl methacrylate (PMMA).

On the surface of one of the pair of substrates, a matrix of Thin Film Transistor (TFT), color filter, black matrix, etc. may be arranged. An alignment film may be further arranged on the surface of the one substrate. The alignment film contains a well-known organic alignment agent or inorganic alignment agent.

The liquid crystal display panel is manufactured using the liquid crystal display element sealing compound of this invention. In the manufacturing method of the liquid crystal display panel, there are usually a liquid crystal dropping process and a liquid crystal injection process. The liquid crystal display panel of the present invention is preferably manufactured by a liquid crystal dropping process.

The method of manufacturing a liquid crystal display panel using a liquid crystal dropping process includes the following steps: 1) forming a sealing pattern of the liquid crystal display element sealant of the present invention on a substrate; 2) in a state where the sealing pattern is not hardened, The liquid crystal is dripped in the area enclosed by the seal pattern, or in the area of the other substrate opposite to the area enclosed by the seal pattern; 3) One substrate and the other substrate are overlapped with the seal pattern interposed therebetween; and 4) Use The seal pattern is hardened.

In the step of 2), the state in which the seal pattern is not cured refers to a state in which the curing reaction of the liquid crystal display element sealing agent has not progressed to the gelation point. Therefore, in the step of 2), in order to suppress the dissolution of the liquid crystal display element sealing agent in the liquid crystal, the sealing pattern may be semi-cured by light irradiation or heating.

In the step 4), the hardening caused by light irradiation can be performed only, or After curing by light irradiation, curing by heating is performed. That is, the step 4) includes the step of irradiating light to the seal pattern to harden the seal pattern; when the liquid crystal display element sealant further includes the thermosetting agent E described above, it may further include the step of irradiating light The step of heating and hardening the sealing pattern. By curing by light irradiation, the liquid crystal display element sealing agent can be cured in a short time, so dissolution in the liquid crystal can be suppressed. By combining the hardening caused by light irradiation and the hardening caused by heating, it is possible to reduce the damage of light to the liquid crystal layer compared with the case of hardening only caused by light irradiation.

The irradiated light is preferably light with a wavelength of 370 nm to 450 nm. The reason is that the light of the wavelength causes relatively little damage to the liquid crystal or the driving electrode. For the irradiation of light, a known light source that emits ultraviolet or visible light can be used. When irradiating visible light, high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, xenon lamps, fluorescent lamps, etc. can be used.

The light irradiation energy should just be the energy of the degree which hardens the curable compound A. The photocuring time also depends on the composition of the liquid crystal display element sealing agent, and is, for example, about 10 minutes.

The thermosetting temperature also depends on the composition of the liquid crystal display element sealing agent, for example, it is 120°C, and the thermosetting time is about 2 hours.

The elution of the liquid crystal display element sealing agent of this invention in a liquid crystal is reduced. Therefore, the liquid crystal display panel which has the hardened|cured material of the liquid crystal display element sealing compound of this invention has little liquid crystal contamination, and can have high-quality display performance.

The photocurable resin composition of the present invention is also effective against long-wavelength light. The compound B exhibiting sufficient light absorption can have good curability. Thereby, the damage to the display element such as the liquid crystal layer can be reduced, and the curing can be performed in a short time.

In addition, since good curability can be obtained, the elution of compound B from the cured product can be reduced. Not only that, but compound B exhibits moderate hydrophilicity and therefore is not easily eluted into the liquid crystal exhibiting hydrophobicity. Even if a small amount of compound B is eluted into the liquid crystal, the sensitivity to visible light is not too high, and it is difficult to cause an unwanted reaction with the liquid crystal. Therefore, good curability in the visible light region can be obtained, and the contamination of liquid crystal can be highly suppressed.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples. The scope of the present invention is not limitedly interpreted by these examples.

1. Preparation and evaluation of compound B and comparative compounds

1-1. Compound B

(Synthesis example 1)

5.6g (0.0225 mol) of 2-chlorothioxanthone and 2.6g (0.0225 mol) of the potassium salt of 2-mercaptoethanol were stirred in 20ml of N,N-dimethylacetamide at 100°C 18 hours. Then, the obtained reaction mixture was poured into 2N hydrochloric acid, and extracted with ethyl acetate. The obtained extract was subjected to conventional post-treatment and purification by chromatography to obtain 3.5 g of compound B-1 (2-(2-hydroxyethylthio)thioxanthone) represented by the following formula.

[化11]

(Synthesis example 2)

5.6g (0.0225 mol) of 2-chlorothioxanthone and 3.2g (0.0225 mol) of potassium salt of 4-mercaptophenol were stirred in 20ml of N,N-dimethylacetamide at 100°C 12 hours. Then, the obtained reaction mixture was poured into 2N hydrochloric acid, and extracted with ethyl acetate. The obtained extract was subjected to usual post-treatment and purification by chromatography to obtain 4.5 g of compound B-2 (2-(4-hydroxyphenylthio)thioxanthone) represented by the following formula.

1-2. Comparative compounds

Compound R-1: 2,4-Diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., KAYACURE DETX-5, refer to the following formula)

[化13]

Compound R-2: 2-isopropylthioxanthone (manufactured by Tokyo Chemical Industry Co., Ltd., refer to the following formula)

Compound R-3: 2-Chlorothioxanthone (manufactured by Tokyo Chemical Industry Co., Ltd., refer to the following formula)

1-3. Evaluation of compound B and comparative compounds

(Experimental example 1~Experimental example 2, Comparative experimental example 1~Comparative experimental example 3)

High performance liquid chromatography (HPLC) was performed on the compound B-1 and compound B-2 obtained in Synthesis Example 1 and Synthesis Example 2, and Comparative Compound R-1~Comparative Compound R-3 Measurement/Liquid Chromatography Mass Spectrometry (LC/MS) measurement to determine the molecular weight. In addition, the following methods were used to evaluate the voltage holding ratio of the liquid crystal and the drop in the N-I point of the liquid crystal.

(Molecular weight)

1) High performance liquid chromatography (HPLC) determination

For the compound B-1 and compound B-2 obtained in Synthesis Example 1 and Synthesis Example 2, and Comparative Compound R-1~Comparative Compound R-3, sample solutions dissolved in tetrahydrofuran (THF) were prepared, respectively, as follows: High performance liquid chromatography (HPLC) measurement was performed under the above measurement conditions. Then, the area percentage of the detected peaks (the ratio of each peak to the total area of all peaks) is obtained.

(HPLC measurement conditions)

Device: manufactured by Waters, AcquityTM UPLC H-Class system

Column: Acquity UPLC BEH C18, 2.1mm ID×100mm Particle size: 1.7μm

Mobile phase: A: Acetonitrile

B: 5mM ammonium acetate aqueous solution

A/B=60/40 (0 minutes~4 minutes)

95/5 (4 minutes to 9 minutes)

95/5 (9 minutes~10 minutes)

Flow rate: 0.4mL/min

PDA detector: measurement wavelength: 190nm~500nm, select wavelength: 400nm

Will be relative to the total area of all detected peaks and all peaks The peak with the highest intensity (the peak with the highest peak height) is referred to as the "main peak".

2) Liquid chromatography mass spectrometry (LC/MS)

The relative molecular weight corresponding to the peak apex of the detected main peak is determined by liquid chromatography mass spectrometry (LC/MS).

(LC/MS measurement conditions)

Device: manufactured by Waters, AcquityTM H-Class system/SQ Detector

Column: Acquity UPLC BEH C18, 2.1mm ID×100mm Particle size: 1.7μm

Mobile phase: A: Acetonitrile

B: 5mM ammonium acetate aqueous solution

A/B=60/40 (0 minutes~4 minutes)

95/5 (4 minutes to 9 minutes)

95/5 (9 minutes~10 minutes)

Flow rate: 0.4mL/min

Ionization: ESI (electrospray ionization), positive/negative ion measurement

PDA detector: measurement wavelength: 190nm~500nm, select wavelength: 400nm

(Voltage retention rate of liquid crystal)

0.1 g of compound B and 1 g of liquid crystal (MLC-7021-000, manufactured by Merck) were put into a vial bottle, and heated at 120°C for 1 hour to obtain a liquid crystal mixture. Then, the liquid crystal mixture was taken out and poured into a glass cell with a transparent electrode formed in advance (KSSZ-10/B111M1NSS05, manufactured by EHC Corporation), a voltage of 1V was applied, and the voltage retention rate at 60 Hz was measured with a 6254 measuring device (Toyo Technica Corporation).

The case where the voltage retention rate was 95% or more was regarded as ⊚, the case where the voltage retention ratio was 90% or more and less than 95% was regarded as ○, and the case where it was less than 90% was regarded as ×.

The higher the voltage holding rate, the more the contamination of the liquid crystal is suppressed.

(The N-I point of the liquid crystal drops)

0.1 g of compound B and 1 g of liquid crystal (MLC-7021-000, manufactured by Merck) were put into a small glass bottle and heated at 120°C for 1 hour to obtain a liquid crystal mixture. Then, 10 mg of the liquid crystal mixture was put into an aluminum open pan (manufactured by Epolead Service), and subjected to differential thermal analysis-thermogravimetric analysis. analysis, DTA-TG) device (manufactured by Seiko Instruments) to measure the NI point (Nematic-Isotropic transition temperature). The measurement is performed by heating the liquid crystal mixture from 55°C to 150°C at a temperature increase rate of 2°C/min.

The case where the amount of change from the N-I point of the liquid crystal was less than 2°C was regarded as ⊚, the case of 2°C or more and less than 5°C was regarded as ○, and the case of 5°C or more was regarded as ×.

Table 1 shows the obtained measurement results.

As shown in Table 1, the compound B-1 and compound B-2 of Experimental Example 1 and Experimental Example 2 are compared with the comparative compound R-1~Comparative compound R-3 of Comparative Experimental Example 1~Comparative Experimental Example 3, the liquid crystal The voltage retention rate and NI point drop results are better. The reason for this is considered to be that the compound B-1 and the compound B-2 have a hydroxyl group in the molecule and exhibit moderate hydrophilicity, so the elution into the liquid crystal exhibiting hydrophobicity is reduced.

2. Preparation and evaluation of photocurable resin composition

(Sclerosing compound A)

Hardening compound A-1:

The following method was used to synthesize methacrylic modified bisphenol F epoxy resin (95% partial methacrylate).

160g of liquid bisphenol F type epoxy resin (YDF-8170C, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent of 160g/eq), 0.1g of p-methoxyphenol as a polymerization inhibitor, as a catalyst The medium 0.2g of triethanolamine and 81.7g of methacrylic acid were added to the flask, and the reaction was carried out for 5 hours while feeding dry air and refluxing and stirring at 90°C. The obtained reaction product was washed 20 times with ultrapure water to obtain a methacrylic acid-modified bisphenol F epoxy resin (curable compound A-1).

The obtained resin was analyzed by HPLC and NMR. As a result, it was confirmed that it was a methacrylic modified bisphenol F epoxy resin in which 95% of the epoxy group was modified with methacrylic acid. In addition, GPC analysis of the obtained resin revealed that the weight average molecular weight was 792.

Hardening compound A-2:

Use the following method to synthesize acrylic modified bisphenol F epoxy resin (50% part Sub-acrylate).

First, mix 175g of bisphenol F epoxy resin (YDF-8170C, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent of 160g) in a 500ml four-necked flask equipped with a stirrer, gas introduction tube, thermometer and condenser. /eq), 37g of acrylic acid, 0.2g of triethanolamine as a catalyst, and 0.2g of hydroquinone monomethyl ether as a polymerization inhibitor, heated and stirred at 110°C for 12 hours while blowing in dry air . The obtained reaction product was repeatedly washed 12 times with ultrapure water to obtain an acrylic modified bisphenol F epoxy resin (curable compound A-2).

The resin was analyzed by HPLC and NMR, and it was found that it was a bisphenol F type epoxy resin in which 50% of the epoxy group was modified with acrylic acid. In addition, GPC analysis of this resin revealed that the weight average molecular weight was 692.

Polyethylene glycol diacrylate represented by the following formula: manufactured by Kyoeisha Chemicals, Light Acrylate 14EG-A, molecular weight 600

(Compound B)

Synthesis Example 1~Compound B-1~Compound B-2 obtained in Synthesis Example 2

(Comparative compound)

Compound R-1~Compound R-3

(Amine-based sensitizer C)

Compound C-1: Polyethylene glycol bis(p-dimethylaminobenzoate) (manufactured by IGM Resins, Omnipol ASA, refer to the following formula)

Compound C-2: 4,4'-bis(dimethylamino)benzophenone (manufactured by Tokyo Chemical Industry Co., Ltd., refer to the following formula)

(Thermosetting compound D)

Epoxy resin: manufactured by Mitsubishi Chemical Corporation, jER1004, softening point 97°C

(Thermal hardener E)

Dihydrazine adipate: manufactured by Nippon Kasei Co., Ltd., ADH, melting point 177℃~184℃

(Other ingredients F)

Silicon dioxide particles: manufactured by Nippon Shokubai Co., Ltd., S-100

Thermoplastic resin particles: manufactured by Aica Industries, F351, softening point 120°C, average particle size 0.3μm

γ-glycidoxypropyltrimethoxysilane: manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403

(Example 1)

Using a three-roll mill, 420 parts by mass of curable compound A-1 and 200 parts by mass of polyethylene glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., Wright Acrylic Ester (Light Acrylate) 14EG-A), 10 parts by mass of compound B as compound B-1 obtained in Synthesis Example 1, and 50 parts by mass of epoxy resin as thermosetting compound D (manufactured by Mitsubishi Chemical Corporation, jER1004 ), 90 parts by mass of dihydrazide adipate (manufactured by Nippon Kasei Co., Ltd., ADH) as a thermosetting agent E, and 130 mass parts of silica particles (manufactured by Nippon Shokubai Co., Ltd., S-100) as a filler , 70 parts by mass of F351 (manufactured by Aica Industrial Co., Ltd.) as thermoplastic resin particles, and 20 parts by mass of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) as silane coupling agent KBM-403) was thoroughly mixed to obtain a photocurable resin composition.

(Example 2~Example 9, Comparative Example 1~Comparative Example 9)

Except having changed to the composition shown in Table 2 or Table 3, it carried out similarly to Example 1, and obtained the photocurable resin composition.

Use the following methods to evaluate the performance of the resulting photocurable resin composition: 示性。 Show characteristics.

(Test of the display characteristics of the LCD panel when it is not powered)

A dispenser (Shot Master: manufactured by Musashi Engineering) was used for the obtained photocurable resin composition, and a transparent electrode and an alignment film were formed on a 40mm×45mm glass substrate (RT-DM88). -PIN, manufactured by EHC Corporation), is formed with a 35mm×40mm quadrangular seal pattern (cross-sectional area 3500μm ² ) (main seal), and the same seal pattern (38mm×43mm quadrangular seal pattern) is formed on the outer periphery.

Then, the liquid crystal (MLC-7021-000, manufactured by Merck) corresponding to the content of the panel after the bonding was precisely dripped into the frame of the main seal using a dispenser. Then, after bonding the paired glass substrates under reduced pressure, the atmosphere is released and bonding is performed. Then, after the two bonded glass substrates were kept in a light-shielding box for 3 minutes, the main seal was shielded by a substrate coated with a 36mm×41mm quadrangular black matrix, and the irradiation wavelength was ^{3000mJ/cm 2} 370nm~450nm light, and then heated at 120°C for 1 hour. Polarizing films were attached to both sides of the obtained panel to obtain a liquid crystal display panel.

The case where the liquid crystal is aligned and no color unevenness up to the main sealing edge of the obtained liquid crystal display panel is evaluated as ◎, and the case where color unevenness occurs in the vicinity of the main sealing edge within a range of less than 1 mm is evaluated as ○ , The case where color unevenness occurs within a range of 1 mm or more from the vicinity of the main seal edge is evaluated as ×.

(Test of the display characteristics of the liquid crystal display panel when the power is turned on)

The liquid crystal display is produced in the same way as the liquid crystal display panel display characteristics test described above Display panel. When the liquid crystal display panel was driven by a DC power supply with an applied voltage of 5V, the case where the liquid crystal display function near the main seal was evaluated as ◎, and white unevenness occurred in the range of less than 1mm near the main seal It was evaluated as ○, and the case where white unevenness occurred in a range of 1 mm or more from the vicinity of the main seal and not normally driven was evaluated as ×.

The evaluation results of Example 1 to Example 9 are shown in Table 2, and the evaluation results of Comparative Example 1 to Comparative Example 9 are shown in Table 3.

As shown in Table 2, it was found that the photocurable resin compositions of Examples 1 to 9 containing the compound B showed good display characteristics both when energized and when not energized. It is considered that the reason is that the compound B has a moderately high sensitivity to visible light, can sufficiently harden the sealant, reduce the elution of the components of the sealant, and also reduce the elution of the compound B itself into the liquid crystal.

Furthermore, as shown in the comparison of Example 1, Example 2, and Example 6, or the comparison of Example 7 to Example 9, it is known that the combination of compound B and an amine-based sensitizer can further reduce non-energized The display of the liquid crystal display panel is uneven at the time. The reason for this is considered to be that the compound B has an amine-based sensitizer that makes it easy to appropriately increase the sensitivity to visible light.

On the other hand, as shown in Table 3, it was found that the photocurable resin compositions of Comparative Example 1 to Comparative Example 9 containing the comparative compound all showed poor characteristics. It is believed that the reason is that none of the comparative compound R-1~the comparative compound R-3 has a structure in which a thioether group is bonded to the thioxanthone skeleton, so the sensitivity to visible light is low, and the sealant cannot be sufficiently It hardens and cannot sufficiently suppress the elution of the sealing compound component into the liquid crystal. In addition, it is considered that the comparative compound R-1 to the comparative compound R-3 do not have a hydrophilic hydroxyl group in the molecule, and therefore cannot sufficiently suppress their own elution into the liquid crystal.

This application claims priority based on Japanese Patent Application No. 2016-11769 filed on January 25, 2016. All the contents recorded in the specification of this application are quoted in the specification of this case.

[Industrial availability]

The present invention can provide a sealant for use as a display element, particularly In the case of a liquid crystal display element sealing agent, a photocurable resin composition that has sufficient curability to visible light and can highly suppress contamination of liquid crystals.

Claims (15)

A display element sealing agent comprising a photocurable resin composition containing a curable compound A having an ethylenically unsaturated double bond in the molecule, and a compound represented by the following general formula (1) B,

In the general formula (1), _{at least one of R 1} to R ₈ is -SX (X is an optionally substituted alkyl group with 1 to 8 carbons, an optionally substituted alkenyl group with 1 to 8 carbons, or a substituted Aryl group), the remaining R ₁ to R ₈ are hydrogen atoms, hydroxyl groups, optionally substituted alkyl groups with 1 to 8 carbons, optionally substituted alkenyl groups with 1 to 8 carbons, or A substituted aryl group, and _{at least one of the X and the remaining R 1} to R ₈ is a hydroxyl group, an alkyl group with 1 to 8 carbons substituted by a hydroxyl group, and an alkenyl group with 1 to 8 carbons substituted by a hydroxyl group , Or an aryl group substituted by a hydroxyl group. The display element sealant described in the first item of the patent application, wherein the compound B is represented by the following general formula (2),

In the general formula (2), X is an alkyl group with 1 to 8 carbons substituted with a hydroxyl group, an alkenyl group with 1 to 8 carbons substituted with a hydroxyl group, or an aryl group substituted with a hydroxyl group. The display element sealant described in the first item of the patent application, wherein the compound B is represented by the following general formula (2'),

In the general formula (2'), X is an alkyl group having 1 to 8 carbon atoms substituted with a hydroxyl group, an alkenyl group having 1 to 8 carbon atoms substituted with a hydroxyl group, or an aryl group substituted with a hydroxyl group. The display element sealing agent described in the first item of the scope of patent application, wherein the photocurable resin composition further contains an amine-based sensitizer C. The display element sealing agent described in the first item of the scope of patent application, wherein the content of the compound B is 0.01% by mass to 10% by mass relative to the curable compound A. The display element sealant described in the first item of the patent application, wherein the sclerosing compound A further has an epoxy group in the molecule. The display element sealant according to the first item of the patent application, wherein the photocurable resin composition further contains a thermosetting compound D having an epoxy group in the molecule (wherein, the thermosetting compound D is set It is different from the curable compound A) and the thermosetting agent E. The display element sealing agent as described in item 7 of the scope of patent application, wherein the thermal hardening agent E is selected from the group consisting of organic acid dihydrazine-based thermal latent hardeners, imidazole-based thermal latent hardeners, and amine adducts. One or more of the group consisting of a thermal latent curing agent and a polyamine-based thermal latent curing agent. The display element sealing agent described in claim 1, wherein the photocurable resin composition further contains an inorganic filler or an organic filler. The display element sealing compound as described in the claim 1st item is a liquid crystal display element sealing compound. A method for manufacturing a liquid crystal display panel includes the following steps: forming a sealing pattern on a substrate using the display element sealant described in item 10 of the scope of patent application; Inject liquid crystal in the area of the seal pattern or on the other substrate paired with the one substrate; superimpose the one substrate and the other substrate with the seal pattern interposed therebetween; and harden the seal pattern . The method for manufacturing a liquid crystal display panel as described in claim 11, wherein the step of hardening the sealing pattern includes a step of irradiating the sealing pattern with light to harden the sealing pattern. The method for manufacturing a liquid crystal display panel as described in claim 12, wherein the light irradiated to the sealing pattern includes light in the visible light region. According to the method for manufacturing a liquid crystal display panel described in claim 12, the step of hardening the sealing pattern further includes a step of heating the sealing pattern irradiated with light to harden it. A liquid crystal display panel comprising: a pair of substrates, a frame-shaped sealing member arranged between the pair of substrates, and liquid crystal filled in a space surrounded by the sealing member between the pair of substrates Layer, and the sealing member is a hardened product of the display element sealant as described in item 10 of the scope of the patent application.