TWI882101B - Sealant for liquid crystal dripping method, method for manufacturing liquid crystal display panel, and liquid crystal display panel - Google Patents

Abstract

The subject of the present invention is to provide a sealing agent for a liquid crystal dropping method that can form a sealing member having good bonding strength with a substrate even when exposed to a high temperature and high humidity environment, a liquid crystal display panel using the same, and a method for manufacturing a liquid crystal display panel. The sealing agent for a liquid crystal dropping method that solves the above-mentioned subject is used in a liquid crystal dropping method. When the sealant used in the liquid crystal dropping method is formed into a film with a thickness of 100 μm, irradiated with 3000 mJ/cm ² of light and heated at 120° C. for 1 hour to form a film, the initial Young's modulus of the film at 120° C. measured by a dynamic viscoelasticity measuring device is 1.0×10 ⁸ Pa or less, and after the film is stored in a 121° C., 100% Rh environment for 24 hours, the difference between the post-PCT Young's modulus of the film at 120° C. measured by a dynamic viscoelasticity measuring device and the initial Young's modulus is 8.0×10 ⁷ Pa or less.

Description

Sealant for liquid crystal dripping method, method for manufacturing liquid crystal display panel, and liquid crystal display panel

The present invention relates to a sealing agent for liquid crystal dripping method, a method for manufacturing a liquid crystal display panel, and a liquid crystal display panel.

Previously, the liquid crystal dropping method was widely used as a method for sealing liquid crystal between a pair of substrates. When a liquid crystal display panel is manufactured by the liquid crystal dropping method, a sealant is applied to form a sealing pattern. Then, liquid crystal is dropped onto the substrate or a paired substrate with the sealing pattern formed thereon, and the substrates are bonded together under vacuum. Then, the sealing pattern is cured by ultraviolet (UV) irradiation or heating, and the liquid crystal is sealed by a sealing member.

Here, various compositions have been proposed as sealants used in the above-mentioned liquid crystal dropping method. For example, a sealant capable of forming a highly flexible sealing member has also been proposed (for example, Patent Document 1 and Patent Document 2). [Prior Art Document] [Patent Document]

[Patent document 1] Japanese Patent Publication No. 2017-197731 [Patent document 2] Japanese Patent Publication No. 2015-206997

[Problems to be solved by the invention] In recent years, with the popularization of tablet terminals or mobile terminals, liquid crystal display panels are used in various environments. For example, it is also required to use liquid crystal display panels in high temperature and high humidity environments. However, previous liquid crystal display panels have the following problems: even in normal environments, the bonding strength between the substrate and the sealing component is high, but if exposed to a high temperature and high humidity environment, the bonding strength is easily reduced. Even a highly flexible sealing component as described in Patent Document 1 or Patent Document 2 is difficult to maintain sufficient bonding strength with the substrate after a high temperature and high humidity test.

Therefore, attempts have been made to suppress the peeling of the sealing component and the substrate during or after storage in a high-temperature and high-humidity environment by further improving the bonding strength between the sealing component and the substrate in a normal environment. However, the inventors have conducted diligent research and found that the bonding strength between the sealing component and the substrate during or after storage in a high-temperature and high-humidity environment is not necessarily related to the bonding strength between the sealing component and the substrate in a normal environment. In other words, it is difficult for the previous method to achieve good bonding strength between the sealing component and the substrate during or after storage in a high-temperature and high-humidity environment. In addition, the moisture resistance of previous sealing components in a high-temperature and high-humidity environment is sometimes insufficient, and sometimes causes adverse conditions in liquid crystal display panels.

The present invention is made in view of the above-mentioned problem. Specifically, a sealing agent for a liquid crystal dripping method capable of forming a sealing member having good bonding strength with a substrate even when exposed to a high temperature and high humidity environment, a liquid crystal display panel using the same, and a method for manufacturing a liquid crystal display panel are provided. In addition, a sealing agent for a liquid crystal dripping method capable of forming a sealing member having good bonding strength with a substrate and high moisture resistance even when exposed to a high temperature and high humidity environment, a liquid crystal display panel using the same, and a method for manufacturing a liquid crystal display panel are also provided. [Means for solving the problem]

The present invention provides the following first sealing agent for liquid crystal dropping method. [1] A sealing agent for a liquid crystal dropping method, which is used in a liquid crystal dropping method, wherein the sealing agent for a liquid crystal dropping method is formed into a film having a thickness of 100 μm, irradiated with light of 3000 mJ/cm ² and heated at 120° C. for 1 hour to form a film, and the initial Young's modulus of the film at 120° C. measured by a dynamic viscoelasticity measuring device is 1.0×10 ⁸ Pa or less, and after the film is stored in a 121° C., 100% Rh environment for 24 hours, the difference between the Young's modulus of the film at 120° C. measured by a dynamic viscoelasticity measuring device after a pressure cooker test (PCT) and the initial Young's modulus is 8.0×10 ⁷ Pa or less.

[2] The sealing agent for liquid crystal dropping method according to [1], comprising a polymerizable compound having a polymerizable functional group, wherein the polymerizable compound comprises a curable monomer having a structure represented by the following general formula (1). ( _R1 in the general formula (1) represents a group selected from [Chemical 2] The groups formed by the above mentioned groups (* indicates a bond), _R2 and _R3 are independently selected from [Chemical 3] The groups formed are (* represents a bond, m, n and p represent integers from 1 to 30), _R4 and _R5 each independently represent a hydrogen atom or a methyl group)

[3] The sealant for liquid crystal dropping method as described in [2], wherein the molecular weight of the curable monomer is 700 or more. [4] The sealant for liquid crystal dropping method as described in [2] or [3], wherein the total amount of the curable monomer relative to the total amount of the polymerizable compound is 10 mass % or more and 30 mass % or less. [5] The sealant for liquid crystal dropping method as described in any one of [2] to [4], further comprising (meth)acrylic thermoplastic polymer particles, wherein the amount of the (meth)acrylic thermoplastic polymer particles is 10 mass % or more.

[6] The sealing agent for liquid crystal dropping method as described in any one of [2] to [5], further comprising at least one thermosetting agent selected from the group consisting of imidazole-based thermosetting agents, amine adduct-based thermosetting agents and polyamine-based thermosetting agents.

The present invention provides the following second liquid crystal dripping method sealant. [7] A liquid crystal dripping method sealant, comprising a polymerizable compound having a polymerizable functional group and a thermosetting agent, wherein the polymerizable compound in the liquid crystal dripping method sealant comprises an epoxy compound, the ratio of the amount of active hydrogen derived from the thermosetting agent in the liquid crystal dripping method sealant to the amount of epoxy groups derived from the epoxy compound in the liquid crystal dripping method sealant is 0.25 or more, and when the liquid crystal dripping method sealant is formed into a film having a thickness of 100 μm, irradiated with 3000 mJ/ ^cm2 of light and heated at 120°C for 1 hour to form a film, the initial Young's modulus of the film at 120°C measured by a dynamic viscoelasticity measuring device is 1.0×10 ⁸ Pa or less, and after the film is stored in a 121° C., 100% Rh environment for 24 hours, the difference between the post-PCT Young's modulus of the film at 120° C. measured by a dynamic viscoelasticity measuring apparatus and the initial Young's modulus is 8.0×10 ⁷ Pa or less.

[8] The sealing agent for liquid crystal dropping method according to [7], wherein the polymerizable compound further comprises a curable monomer having a structure represented by the following general formula (1). ( _R1 in the general formula (1) represents a group selected from [Chemical 2] The groups formed by the above mentioned groups (* indicates a bond), _R2 and _R3 are independently selected from [Chemical 3] The groups formed are (* represents a bond, m, n and p represent integers from 1 to 30), _R4 and _R5 each independently represent a hydrogen atom or a methyl group)

[9] The sealant for liquid crystal dropping method as described in [8], wherein the molecular weight of the curable monomer is 700 or more. [10] The sealant for liquid crystal dropping method as described in [8] or [9], wherein the total amount of the curable monomer relative to the total amount of the polymerizable compound is 10 mass % or more and 30 mass % or less. [11] The sealant for liquid crystal dropping method as described in any one of [7] to [10], further comprising a curing catalyst, wherein the melting point of the curing catalyst is 100°C or more.

[12] The sealant for liquid crystal dripping method as described in any one of [7] to [11], further comprising coated particles, wherein the coated particles have a core comprising inorganic particles and a polymer layer covering the core, and the coated particles have a functional group comprising an epoxy group and/or a carbon-carbon double bond on the surface. [13] The sealant for liquid crystal dripping method as described in [12], wherein the polymer layer comprises a crosslinked polymer. [14] The sealant for liquid crystal dripping method as described in [12] or [13], wherein the average particle size of the coated particles is 0.2 μm to 10 μm.

The present invention also provides the following method for manufacturing a liquid crystal display panel. [15] A method for manufacturing a liquid crystal display panel, comprising: a step of coating a sealant for a liquid crystal dripping method as described in any one of [1] to [14] on one of a pair of substrates to form a sealing pattern; a step of dripping liquid crystal in the area of the sealing pattern of one of the substrates or on the other substrate when the sealing pattern is not hardened; a step of overlapping the one substrate and the other substrate with the sealing pattern interposed therebetween; and a step of hardening the sealing pattern.

[16] The method for manufacturing a liquid crystal display panel as described in [15], wherein, in the step of hardening the sealing pattern, the sealing pattern is irradiated with light. [17] The method for manufacturing a liquid crystal display panel as described in [16], wherein the light includes visible light.

[18] The method for manufacturing a liquid crystal display panel as described in [16] or [17], wherein, in the step of curing the sealing pattern, heating is performed after irradiating light.

The present invention also provides the following liquid crystal display panel. [19] A liquid crystal display panel comprising a cured product of a sealant for a liquid crystal dripping method as described in any one of [1] to [14]. [Effect of the invention]

The first liquid crystal dripping method sealant of the present invention can form a sealing member having good bonding strength with the substrate even when exposed to a high temperature and high humidity environment. Therefore, it can be applied to liquid crystal display panels used in various environments. In addition, the second liquid crystal dripping method sealant of the present invention can form a sealing member having good bonding strength with the substrate and high moisture resistance even when exposed to a high temperature and high humidity environment. Therefore, it can be applied to liquid crystal display panels used in various environments.

1. Sealant for liquid crystal dripping method The sealant for liquid crystal dripping method of the present invention (hereinafter, also referred to as "sealant") is a composition of a sealing member for manufacturing a liquid crystal display panel, and can be preferably used in the case of manufacturing a liquid crystal display panel by a liquid crystal dripping method. Among them, it can also be used to manufacture a liquid crystal display panel by a liquid crystal injection method, etc. The following describes two embodiments of the sealant for liquid crystal dripping method.

1-1. Sealant for the first liquid crystal dripping method As described above, the sealing components obtained by the previous sealant are often: if exposed to a high temperature and high humidity environment, the bonding strength to the substrate is reduced. Moreover, if such a reduction in bonding strength occurs, it is easy to cause adverse conditions such as liquid crystal leakage.

In contrast, the inventors have made a study that by adjusting the Young's modulus of the cured product of the sealant to a predetermined range, the sealing member and the substrate can have good bonding strength during or after storage in a high temperature and high humidity environment. Specifically, it has been found that when the initial Young's modulus at 120°C of a film formed by curing the sealant under predetermined conditions is 1.0×10 ⁸ Pa or less, and the difference between the post-PCT Young's modulus at 120°C of the film after storage in a 100% Rh environment for 24 hours and the initial Young's modulus is 8.0×10 ⁷ Pa or less, the sealing member has excellent bonding strength to the substrate even when exposed to a high temperature and high humidity environment.

The reason is speculated as follows. Generally, if the cured product of the sealant (sealing member) is exposed to a high temperature and high humidity environment, the sealing member expands due to the heat, thereby applying stress to the interface between the sealing member and the substrate. In addition, due to the heat or moisture in the high temperature and high humidity environment, the unreacted components (such as epoxy groups, etc.) in the sealing member react with each other, or the unreacted components react with the moisture in the environment, thereby generating strain inside the sealing member. Moreover, due to the strain, stress is easily generated at the interface between the sealing member and the substrate, and the sealing member and the substrate are easily separated.

In contrast, if the Young's modulus (initial Young's modulus) of the cured product of the sealant (sealing member) at 120°C is 1.0×10 ⁸ Pa or less as in the present embodiment, the sealing member is relatively soft and can absorb the stress generated at the interface between the substrate and the sealing member. Furthermore, the small change in the Young's modulus after PCT and the initial Young's modulus after being placed in a high temperature and high humidity environment indicates that the state change in the high temperature and high humidity environment is small, that is, the strain generated in the sealing member is small. Therefore, the substrate and the sealing member can maintain high bonding strength during or after storage in a high temperature and high humidity environment.

Here, the initial Young's modulus can be measured as follows. First, the sealant is applied to a release paper with a thickness of 100 μm using an applicator to form a 100 μm film. Then, it is placed in a nitrogen replacement container and flushed with nitrogen for 5 minutes, and then irradiated with 3000 mJ/ ^cm2 of light (light calibrated with a wavelength of 365 nm sensor), and then heated at 120°C for 1 hour to form a film.

Then, the obtained film is cut into pieces with a length of 35 mm and a width of 10 mm, and the storage elastic modulus is measured by heating from 25°C to 170°C using a dynamic viscoelasticity measuring device (e.g., Dynamic Mechanical Analyzer (DMA), manufactured by Seiko Instruments, DMS6100). Then, the storage elastic modulus at 120°C among the obtained results is taken as the initial Young's modulus. Furthermore, the initial Young's modulus is more preferably 1.0×10 ⁶ Pa to 1.0×10 ⁸ Pa, and further preferably 1.0×10 ⁷ Pa to 5.0×10 ⁷ Pa.

On the other hand, the Young's modulus after PCT can be measured as follows. First, a film prepared in the same manner as described above is left to stand for 24 hours at 121°C and 100% Rh. Then, the temperature is lowered to room temperature, and the storage modulus is measured by raising the temperature from 25°C to 170°C using a dynamic viscoelasticity measuring device (e.g., DMA, DMS6100 manufactured by Seiko Instruments). Then, the storage modulus at 120°C in the obtained result is taken as the Young's modulus after PCT. Furthermore, the difference between the Young's modulus after PCT and the initial Young's modulus is preferably less than 8.0×10 ⁷ Pa, and further preferably less than 7.0×10 ⁷ Pa.

Here, in order to adjust the initial Young's modulus or the post-PCT Young's modulus to the above range, it is sufficient to adjust the composition of the sealant. The sealant of the present invention preferably contains a polymerizable compound having a polymerizable functional group or a photopolymerization initiator, a thermosetting agent, (meth) acrylic thermoplastic particles, etc. The components constituting the sealant are described in detail below.

(1) Polymerizable compound The sealant of this embodiment usually contains a polymerizable compound having a polymerizable functional group. In this specification, the so-called polymerizable functional group refers to a functional group that is activated by light irradiation or heating, a heat curing agent or a photopolymerization initiator, a catalyst, etc. and undergoes a polymerization reaction. Examples of the polymerizable functional group include (meth)acrylic acid, vinyl, acrylamide, epoxy, isocyanate, silanol, etc. In addition, the description of (meth)acrylic acid in this specification means methacrylic acid, acrylic acid, or both of the above, and the description of (meth)acrylic acid means methacrylic acid, acryl, or both of the above.

The polymerizable compound may be a monomer, an oligomer, or a polymer, but from the viewpoint of the coating property of the sealant, a monomer or an oligomer is preferred. In addition, the sealant of the present embodiment may contain only one type of the polymerizable compound, or may contain two or more types.

Here, if the polymerizable compound contains a curable monomer represented by the following general formula (1), the initial Young's modulus or the Young's modulus after PCT of the cured product of the sealant is likely to be within the above range. In the general formula (1), R ₁ represents a compound selected from [Chemical 5] In other words, R ₁ is a structure derived from bisphenol A, bisphenol E or bisphenol F, and among these, a structure derived from bisphenol A or bisphenol F is preferred.

In addition, _R2 and _R3 in the general formula (1) are independently selected from [Chemical 6] In the group formed, the radicals (* represents a bond) are represented. In addition, m, n and p each represent an integer of 1 to 30, and m, n and p are more preferably 2 to 10. Furthermore, R ₄ and R ₅ in the general formula (1) each independently represent a hydrogen atom or a methyl group.

Here, the molecular weight (or weight average molecular weight) of the curable monomer is preferably 700 or more, and more preferably 750 to 1300. If the molecular weight (or weight average molecular weight) of the curable monomer is 700 or more, the cured product of the curable monomer becomes soft, and the effect of absorbing the stress generated at the interface between the substrate and the sealing member becomes higher. The molecular weight of the curable monomer can be adjusted according to the number of n, m or p in the general formula (1), that is, the amount of the structure derived from ethylene oxide or the structure derived from propylene oxide. In addition, the weight average molecular weight of the curable monomer can be measured, for example, by gel permeation chromatography (GPC) (polystyrene conversion).

The total amount of the curable monomer is preferably 10% by mass or more and 30% by mass or less, and more preferably 10% by mass or more and 20% by mass or less relative to the total amount of the polymerizable compound. If the amount of the curable monomer is too much, the display characteristics of the liquid crystal display panel may be affected by the curable monomer. In contrast, if the amount of the curable monomer is 30% by mass or less, the display characteristics of the liquid crystal display panel are likely to be good. On the other hand, if the amount of the curable monomer is 10% by mass or more, the initial Young's modulus and the post-PCT Young's modulus are likely to be within the range.

Here, the polymerizable compound preferably includes, in addition to the curable monomer, an epoxy compound or a (meth)acrylic-epoxy-containing compound, a (meth)acrylic compound other than the curable monomer (hereinafter, also referred to as "(meth)acrylic compound"), etc. If the polymerizable compound includes these, the bonding strength between the obtained sealing member and the substrate is likely to be improved, or the display characteristics of the liquid crystal display panel are likely to be improved.

The epoxy compound may be any compound having an epoxy group (except compounds corresponding to the (meth) acrylic acid-epoxy compound described later). The number of epoxy groups contained in one molecule of the epoxy compound is preferably two or more. If the number of epoxy groups in the epoxy compound is two or more, the adhesion between the obtained sealing member and the substrate of the liquid crystal display panel becomes good. Furthermore, the moisture resistance of the obtained sealing member is also easily improved.

The epoxy compound may be in a liquid or solid state at room temperature. From the viewpoint of setting the viscosity of the sealant to a desired range, the softening point of the epoxy compound is preferably 40°C to 120°C.

In addition, the epoxy compound can be a monomer, an oligomer, or a polymer. The molecular weight (or weight average molecular weight) of the epoxy compound is generally preferably 220 to 3000, more preferably 250 to 2500, and further preferably 300 to 2000. Among them, relative to the total amount of the epoxy compound, the proportion of components with a molecular weight of 500 or more is preferably 25% by mass or more. Epoxy compounds with a molecular weight of 500 or more are not easily dissolved in liquid crystals when making liquid crystal display panels. Therefore, the display characteristics of the obtained liquid crystal display panel become good. The weight average molecular weight of the epoxy compound can be measured, for example, by gel permeation chromatography (GPC) (polystyrene conversion).

Here, the structure of the epoxy compound is not particularly limited, and examples thereof include aromatic epoxy compounds containing an aromatic ring in the main chain. Examples of aromatic epoxy compounds include aromatic polyglycidyl ether compounds obtained by reacting aromatic diols represented by bisphenol A, bisphenol S, bisphenol F, bisphenol AD, etc., or diols obtained by modifying these diols with ethylene glycol, propylene glycol, or alkanediol, with epichlorohydrin; novolac-type polyglycidyl ether compounds obtained by reacting novolac resins derived from phenol or cresol and formaldehyde, or polyphenols represented by polyalkenylphenol or copolymers thereof, with epichlorohydrin; glycidyl ether compounds of xylylphenol resins; naphthalene-type epoxy compounds; diphenyl ether-type epoxy compounds; biphenyl-type epoxy compounds, etc.

More specifically, the aromatic epoxy compound is preferably a cresol novolac epoxy compound, a phenol novolac epoxy compound, a bisphenol A epoxy compound, a bisphenol F epoxy compound, a trisphenol methane epoxy compound, a trisphenol ethane epoxy compound, a trisphenol epoxy compound, a diphenyl ether epoxy compound, or a biphenyl epoxy compound. The polymerizable compound may contain only one epoxy compound or two or more epoxy compounds.

Here, the total amount of the epoxy compound is preferably 5 mass % to 70 mass %, and more preferably 10 mass % to 50 mass % relative to the total amount of the polymerizable compound. If the amount of the epoxy compound in the polymerizable compound is 5 mass % or more, the bonding strength between the cured sealant and the substrate of the liquid crystal display panel is easily improved. On the other hand, if the amount of the epoxy compound is 70 mass % or less, the unreacted components contained in the obtained sealing member are easily reduced. Therefore, the difference between the post-PCT Young's modulus and the initial Young's modulus of the cured sealant is easily reduced.

On the other hand, the so-called (meth)acrylic-epoxy-containing compound refers to a compound having an epoxy group and a (meth)acrylic group in one molecule. When the polymerizable compound includes the epoxy compound and the curable monomer, there is a case where the compatibility of these is low. In contrast, if the polymerizable compound further includes a (meth)acrylic-epoxy-containing compound, the compatibility of the epoxy compound and the curable monomer is improved. Furthermore, the (meth)acrylic-epoxy-containing compound can also be used to suppress the dissolution of the epoxy compound into the liquid crystal.

Here, the number of epoxy groups and (meth)acrylic groups in one molecule of the (meth)acrylic-epoxy-containing compound is not particularly limited, and may be, for example, one or more. In addition, the number of epoxy groups and the number of (meth)acrylic groups may be the same or different. Examples of the (meth)acrylic-epoxy-containing compound include (meth)acrylic-modified epoxy compounds obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of an alkaline catalyst.

The epoxy compound used in the preparation of the (meth)acrylic acid-modified epoxy compound may be any epoxy compound having two or more epoxy groups in the molecule, including bisphenol-type epoxy compounds such as bisphenol A type, bisphenol F type, 2,2'-diallylbisphenol A type, bisphenol AD type, and hydrogenated bisphenol type; novolac-type epoxy compounds such as phenol novolac type, cresol novolac type, biphenyl novolac type, and trisphenol novolac type; biphenyl-type epoxy compounds; naphthalene-type epoxy compounds, and the like.

Among them, (meth)acrylic acid-modified epoxy compounds obtained by (meth)acrylic acid-modified polyfunctional epoxy compounds such as trifunctional or tetrafunctional have high crosslinking density during curing. Therefore, if the sealant contains such (meth)acrylic acid-modified epoxy compounds, it may be difficult to satisfy the initial Young's modulus. Therefore, (meth)acrylic acid-modified epoxy compounds obtained by (meth)acrylic acid-modified bifunctional epoxy compounds are preferred.

Therefore, the epoxy compound used in the preparation of the (meth)acrylic acid modified epoxy compound is preferably a biphenyl type epoxy compound, a naphthalene type epoxy compound and a bisphenol type epoxy compound. From the viewpoint of the coating efficiency of the sealant, a bisphenol type epoxy compound such as bisphenol A type and bisphenol F type is more preferred. Furthermore, the epoxy compound used in the preparation of the (meth)acrylic acid modified epoxy compound may be one type or two or more types. In addition, the epoxy compound used in the preparation of the (meth)acrylic acid modified epoxy compound is preferably highly purified by molecular distillation, washing method, etc.

In addition, the reaction between the epoxy compound and (meth)acrylic acid can be carried out according to a conventional method. When the reaction is carried out, (meth)acrylic acid reacts with a part of the epoxy groups in the epoxy compound to obtain a (meth)acrylic acid-modified epoxy compound having a (meth)acrylic group and an epoxy group.

Here, the molecular weight (weight average molecular weight) of the (meth)acrylic-epoxy-containing compound is preferably 310 to 1000, more preferably 350 to 900. The weight average molecular weight of the (meth)acrylic-epoxy-containing compound can be measured by gel permeation chromatography (GPC), for example (polystyrene conversion). When the molecular weight of the (meth)acrylic-epoxy-containing compound is within this range, the viscosity of the sealant is likely to be within a desired range.

The total amount of the (meth)acrylic-epoxy-containing compound is preferably 30% to 80% by mass, and more preferably 40% to 70% by mass, relative to the total amount of the polymerizable compound. If the amount of the (meth)acrylic-epoxy-containing compound in the polymerizable compound is 40% by mass or more, the compatibility of the curable monomer and the epoxy compound is easily improved. On the other hand, if the amount of the (meth)acrylic-epoxy-containing compound is 70% by mass or less, the initial Young's modulus or the Young's modulus after PCT is easily within the desired range.

In addition, the (meth)acrylic compound is a compound containing one or more (meth)acrylic groups in one molecule and is a compound without an epoxy group (except for the compound corresponding to the curable monomer). The (meth)acrylic compound may be a monomer, an oligomer, or a polymer.

The number of (meth)acrylic groups contained in one molecule of the (meth)acrylic compound is preferably two or more. When the number of (meth)acrylic groups in the (meth)acrylic compound is two or more, the photocurability of the sealant becomes good.

Here, examples of the (meth)acrylic compound include di(meth)acrylates of polyethylene glycol, propylene glycol, polypropylene glycol, etc.; di(meth)acrylate of tri(2-hydroxyethyl)isocyanurate; di(meth)acrylate of a diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol; di(meth)acrylate or tri(meth)acrylate of a triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trihydroxymethylpropane; tri(meth)acrylate of tri(2-hydroxyethyl)isocyanurate; tri(meth)acrylate of trihydroxymethylpropane or its oligomer; tri(meth)acrylate of pentaerythritol or its oligomer; ; poly(meth)acrylate of dipentaerythritol; tri(acryloxyethyl) isocyanurate; caprolactone-modified tri(acryloxyethyl) isocyanurate; caprolactone-modified tri(methacryloxyethyl) isocyanurate; poly(meth)acrylate of dipentaerythritol modified by alkyl; poly(meth)acrylate of dipentaerythritol modified by caprolactone; di(meth)acrylate of hydroxytrimethylacetic neopentyl glycol; di(meth)acrylate of hydroxytrimethylacetic neopentyl glycol modified by caprolactone; (meth)acrylate of ethylene oxide-modified phosphoric acid; (meth)acrylate of ethylene oxide-modified alkylated phosphoric acid; oligomeric (meth)acrylate of neopentyl glycol, trihydroxymethylpropane and pentaerythritol, etc.

Among these, the glass transition temperature of the (meth)acrylic compound is preferably 25°C or higher and 200°C or lower from the viewpoint that the initial Young's modulus of the cured product of the sealant is easily within the desired range. The glass transition temperature is more preferably 40°C to 200°C, and further preferably 50°C to 150°C. The glass transition temperature can be measured by a viscoelasticity measuring device (Dynamic Mechanical Spectrometer, DMS).

The molecular weight (or weight average molecular weight) of the (meth)acrylic compound is preferably 310 to 1000, more preferably 400 to 900. The weight average molecular weight of the (meth)acrylic compound can be measured by gel permeation chromatography (GPC), for example (polystyrene conversion). When the molecular weight of the (meth)acrylic compound is within this range, the viscosity of the sealant is likely to be within the desired range.

The amount of the (meth)acrylic compound is preferably 5% to 70% by mass, more preferably 10% to 50% by mass, relative to the total amount of the polymerizable compound. If the amount of the (meth)acrylic compound is 5% by mass or more, the photocurability of the sealant tends to be good. On the other hand, if the amount of the (meth)acrylic compound is 70% by mass or less, the moisture resistance of the obtained sealing member tends to be good.

Furthermore, the total amount of the polymerizable compound (the total amount of the curable monomer, the epoxy compound, the (meth)acrylic-epoxy-containing compound, and the (meth)acrylic compound) is preferably 60% to 80% by mass, and more preferably 65% to 75% by mass, relative to the total amount of the sealant. If the polymerizable compound is contained in the sealant within this range, the curability of the sealant becomes good, and a high-strength sealing member can be obtained.

(2) Photopolymerization initiator The sealant preferably contains a photopolymerization initiator. The photopolymerization initiator may be any compound that can generate active species by irradiation with light, and may be a self-cleaving type photopolymerization initiator or a dehydrogenating type photopolymerization initiator. The sealant may contain only one type of photopolymerization initiator or may contain two or more types.

Examples of the self-cleaving photopolymerization initiator include alkyl phenone compounds (e.g., benzyl dimethyl ketal such as 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE 651 manufactured by BASF), α-aminoalkyl phenone such as 2-methyl-2-oxo-(4-thiomethylphenyl)propane-1-one (IRGACURE 907 manufactured by BASF), 1-hydroxy-cyclohexyl-phenyl- ketone (IRGACURE 184 manufactured by BASF) and other α-hydroxy phenyl alkyl ketones, etc.); acyl phosphine oxide compounds (such as 2,4,6-trimethylbenzoin diphenylphosphine oxide, etc.); diocene titanium compounds (such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, etc.); acetophenone compounds (such as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1 -ketone, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholinyl (4-thiomethylphenyl) propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone, etc.); benzoyl formic acid ester compounds (such as methyl benzoyl formic acid, etc.); benzoin ether compounds (such as benzoin, Benzoin methyl ether, benzoin isopropyl ether, etc.); oxime ester compounds (such as 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzoyl oxime)] (IRGACURE OXE01 manufactured by BASF), ethyl ketone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime) (IRGACURE OXE02 manufactured by BASF), etc.).

Examples of dehydrogenation-type photopolymerization initiators include benzophenone compounds (e.g., benzophenone, methyl o-benzoylbenzoate-4-phenylbenzophenone, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetrakis(tert-butylcarbonylperoxide)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, etc.); thioxanthrone compounds (e.g., thioxanthrone, 2-chlorothioxanthrone, 1-chloro-4-propoxythioxanthrone, 1-chloro-4-ethoxythioxanthrone (Speedcure CPTX manufactured by Lambson Limited), 2-isopropylthioxanthrone (Lambson Limited), Limited), 4-isopropylthioanthraquinone, 2,4-dimethylthioanthraquinone, 2,4-diethylthioanthraquinone (Speedcure DETX manufactured by Lambson Limited), 2,4-dichlorothioanthraquinone (Omnipol-TX manufactured by IGM Regins Co., Ltd.); anthraquinone compounds (e.g. 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, etc.), 2-hydroxyanthraquinone (2-Hydroxyanthraquinone manufactured by Tokyo Chemical Industry Co., Ltd.), 2,6-dihydroxyanthraquinone (Anthraflavic manufactured by Tokyo Chemical Industry Co., Ltd.); Acid), 2-hydroxymethylanthraquinone (2-(Hydroxymethyl)anthraquinone manufactured by Junsei Chemical Co., Ltd.), etc.); benzoyl compounds, etc.

The absorption wavelength of the photopolymerization initiator is not particularly limited, and for example, a photopolymerization initiator that absorbs light with a wavelength of 360 nm or more is preferred. Among them, a photopolymerization initiator that absorbs light in the visible light region is more preferred, and a photopolymerization initiator that absorbs light with a wavelength of 360 nm to 780 nm is further preferred, and a photopolymerization initiator that absorbs light with a wavelength of 360 nm to 430 nm is particularly preferred.

Examples of photopolymerization initiators that absorb light at a wavelength of 360 nm or longer include alkyl phenone compounds, acyl phosphine oxide compounds, titanocene compounds, oxime ester compounds, thioxanthrone compounds, and anthraquinone compounds, preferably alkyl phenone compounds or oxime ester compounds.

Furthermore, the structure of the photopolymerization initiator can be identified by combining high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS) with nuclear magnetic resonance (NMR) or infrared (IR) analysis.

The molecular weight of the photopolymerization initiator is preferably, for example, 200 or more and 5000 or less. If the molecular weight of the photopolymerization initiator is 200 or more, the photopolymerization initiator is not easily eluted into the liquid crystal when the sealant contacts the liquid crystal. On the other hand, if the molecular weight is 5000 or less, the compatibility with the (meth) acrylic acid compound and the like is improved, and the curability of the sealant is easily improved. The molecular weight of the photopolymerization initiator is more preferably 230 or more and 3000 or less, and further preferably 230 or more and 1500 or less.

The molecular weight of the photopolymerization initiator can be determined as the "relative molecular mass" of the molecular structure of the main peak detected during analysis using high performance liquid chromatography (HPLC).

Specifically, a sample solution is prepared by dissolving a photopolymerization initiator in tetrahydrofuran (THF), and then 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 calculated to confirm the presence or absence of a main peak. The so-called main peak refers to the peak with the highest intensity (the peak with the highest peak height) among all peaks detected at a characteristic detection wavelength for each compound (for example, 400 nm for thioxanthrone compounds). 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 relative to the total amount of the sealant is preferably 0.1 mass % to 15 mass %, more preferably 0.5 mass % to 10 mass %, and further preferably 1 mass % to 10 mass %. If the amount of the photopolymerization initiator is 0.1 mass % or more, the photocurability of the sealant is easily improved. If the amount of the photopolymerization initiator is 15 mass % or less, the photopolymerization initiator is not easily eluted into the liquid crystal.

(3) Thermosetting agent The sealant preferably contains a thermosetting agent. The thermosetting agent may be any component that can cure the polymerizable compound, especially the epoxy compound or the (meth)acrylic-epoxy-containing compound, by heating. The thermosetting agent is preferably a compound that does not cure the epoxy compound or the (meth)acrylic-epoxy-containing compound under normal storage conditions (room temperature, visible light, etc.), but cures these compounds by heating. A sealant containing such a thermosetting agent can achieve both storage stability and thermosetting properties.

In addition, the solubility of the thermosetting agent in water at 20° C. is preferably 5 g/100 g or less, more preferably 3 g/100 g or less, and further preferably 1 g/100 g or less. If the solubility of the thermosetting agent in water is within this range, it is not easy to dissolve into the liquid crystal together with water in the atmosphere.

As the thermosetting agent, a compound capable of curing epoxy compound (hereinafter, also referred to as "epoxy curing agent") is preferably used.

From the viewpoint of improving the viscosity stability of the sealant without impairing the moisture resistance of the obtained sealing member, the melting point of the epoxy curing agent is preferably 50°C or more and 250°C or less, more preferably 100°C or more and 200°C or less, and further preferably 150°C or more and 200°C or less. If the melting point of the epoxy curing agent is within this range, the sealant can be one-liquid curing. If the sealant is one-liquid curing, it is not necessary to mix the main agent and the curing agent when using it, so the workability is excellent.

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

Examples of organic acid dihydrazide-based thermal latent curing agents include adipic acid dihydrazide (melting point 181°C), 1,3-bis(hydrazinocarbonylethyl)-5-isopropylhydantoin (melting point 120°C), 7,11-octadecadiene-1,18-dicarbonylhydrazide (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°C to 225°C) and 2-phenylimidazole (melting point: 137°C to 147°C).

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

The amine addition-based thermal latent curing agent is a thermal latent curing agent comprising an addition compound obtained by reacting an amine compound having catalytic activity with an arbitrary compound. Examples of amine addition-based thermal latent hardeners 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, Amicure PN-31 (melting point 115°C) manufactured by Ajinomoto Fine-Techno, 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 131°C) manufactured by Ajinomoto Fine-Techno.

Polyamine-based heat latent hardeners are heat latent hardeners having a polymer structure obtained by reacting amines with epoxides, and examples thereof include Adeka Hardener EH4339S (softening point 120°C to 130°C) manufactured by Adeka Corporation and Adeka Hardener EH4357S (softening point 73°C to 83°C) manufactured by Adeka Corporation.

Among the above, imidazole-based heat latent curing agents, amine adduct-based heat latent curing agents, or polyamine-based heat latent curing agents are preferred from the viewpoints of availability, compatibility with other components, etc. The sealant may contain only one epoxy curing agent, or may contain two or more.

The content of the thermosetting agent is preferably 1 mass % to 20 mass %, more preferably 2 mass % to 18 mass %, and further preferably 3 mass % to 15 mass % relative to the total amount of the sealant. When the amount of the thermosetting agent is within this range, the thermosetting property of the sealant becomes good.

(4) (Meth)acrylic thermoplastic polymer particles In addition, the sealant preferably further comprises (meth)acrylic thermoplastic polymer particles (hereinafter also referred to as "polymer particles"). In terms of ensuring good dispersibility in the sealant, the average particle size of the polymer particles is preferably 0.05 μm to 5 μm, and more preferably 0.07 μm to 3 μm. The average particle size is a value measured by the Coulter counter method.

The softening point temperature of the polymer particles is preferably 50°C to 120°C, more preferably 60°C to 80°C. If the softening point temperature of the polymer particles is within this range, when the sealant is heated, the (meth) acrylic thermoplastic polymer melts and is compatible with other components in the sealant. Moreover, the compatible (meth) acrylic thermoplastic polymer swells to suppress the viscosity reduction of the sealant before curing. As a result, the components in the sealant are not easily dissolved into the liquid crystal.

The polymer particles can be particles of a polymer containing structural units derived from a (meth)acrylate monomer, but are preferably particles of a polymer obtained by copolymerizing a (meth)acrylate monomer with other monomers. The amount of structural units derived from (meth)acrylate in the polymer particles is preferably 50% by mass to 99.9% by mass, and more preferably 60% by mass to 80% by mass. On the other hand, the amount of structural units derived from other monomers in the polymer particles is preferably 0.1% by mass to 50% by mass, and further preferably 20% by mass to 40% by mass.

Examples of (meth)acrylate monomers include monofunctional (meth)acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and glycidyl (meth)acrylate. Among these, methyl (meth)acrylate, butyl acrylate, and 2-ethylhexyl (meth)acrylate are preferred. The polymer particles may include only one structure derived from these, or may include two or more structures.

On the other hand, examples of other monomers include acrylamides; acid monomers such as (meth) acrylic acid, itaconic acid, and maleic acid; aromatic vinyl compounds such as styrene and styrene derivatives; conjugated dienes such as 1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, and chloroprene; polyfunctional monomers such as divinylbenzene and diacrylates, etc. The polymer particles may contain only one structure derived from other monomers, or may contain two or more structures.

Here, the polymer particles may be either non-crosslinked or crosslinked, and may also be a composite type having a core-shell structure including a crosslinked core and a non-crosslinked shell. Whether the polymer particles are non-crosslinked or crosslinked can be adjusted by the type of other monomers.

The content of the polymer particles is preferably 3% by mass or more, more preferably 5% by mass to 30% by mass, based on the total amount of the sealant. When the amount of the polymer particles is within this range, the moisture resistance of the obtained sealing member becomes good.

(5) Inorganic particles The sealant may further contain inorganic particles. If the sealant contains inorganic particles, the viscosity of the sealant and the strength and linear expansion of the obtained sealing member are likely to be improved.

Examples of materials of inorganic particles 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 titanium oxide, kaolin, talc, glass beads, sericite, activated clay, bentonite, aluminum nitride, silicon nitride, etc. The sealant may contain only one type of inorganic particles or may contain two or more types. Among the above, the inorganic particles are preferably silicon dioxide or talc.

The shape of the inorganic particles may be a fixed shape such as spherical, plate-like, needle-like, or an indefinite shape. When the inorganic particles are spherical, the average primary particle size of the inorganic particles 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 inorganic particles can be measured by the laser diffraction method described in Japanese Industrial Standards (JIS) Z8825-1. The specific surface area of the inorganic particles can be measured by the Brunauer-Emmett-Teller method (BET method) described in JIS Z8830.

The content of the inorganic particles is preferably 0.1 mass % to 25 mass %, more preferably 3 mass % to 20 mass %, and even more preferably 5 mass % to 18 mass % relative to the total amount of the sealant. If the content of the inorganic particles is 0.1 mass % or more, the moisture resistance of the obtained sealing member is easily improved, and if it is 25 mass % or less, the coating stability of the sealant is not easily impaired.

(6) Organic particles In addition to the (meth)acrylic thermoplastic polymer particles or inorganic particles, the sealant may further contain organic particles. If the sealant contains organic particles, it is easy to adjust the elastic modulus of the sealant after light curing.

Examples of organic particles include silicone particles, styrene particles such as styrene-divinylbenzene copolymers, and polyolefin particles. The sealant may contain only one type of organic particles or two or more types. The average primary particle size of the organic particles is preferably 0.05 μm to 13 μm, more preferably 0.1 μm to 10 μm, and even more preferably 0.1 μm to 8 μm.

In addition, the shape of the organic particles is not particularly limited, but preferably spherical, and more preferably round. The so-called spherical means that the ratio of the minimum value (b) of the diameter of each particle to the maximum value (a) is b/a=0.9 to 1.0. The average primary particle size of the organic particles can be measured by microscopy, specifically, by electron microscope image analysis. In addition, the surface of the organic particles is preferably smooth. If the surface is smooth, the specific surface area is reduced, and the amount of organic particles that can be added to the sealant is increased.

The content of the organic particles is preferably 0.1 mass % to 20 mass %, more preferably 1 mass % to 15 mass %, and further preferably 3 mass % to 12 mass % relative to the total amount of the sealant. If the amount of the organic particles is within this range, the Young's modulus of the sealant after light curing is likely to be within a desired range.

(7) Others The sealant of this embodiment may further include additives such as thermal free radical polymerization initiators, coupling agents such as silane coupling agents, ion scavengers, ion exchange agents, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoaming agents as needed.

Examples of silane coupling agents include vinyl trimethoxysilane, γ-(meth)acryloxypropyl trimethoxysilane, γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropyl triethoxysilane, etc. The amount of the silane coupling agent is preferably 0.01 mass% to 6 mass%, more preferably 0.1 mass% to 5 mass%, and further preferably 0.5 mass% to 3 mass% relative to the total amount of the sealant. If the content of the silane coupling agent is 0.01 mass% or more, the obtained sealing component is likely to have sufficient adhesion.

The sealant may further include spacers for adjusting the gap of the liquid crystal display panel.

The total amount of other components is preferably 1 mass % to 50 mass % relative to the total amount of the sealant. If the total amount of other components is 50 mass % or less, the viscosity of the sealant is unlikely to increase excessively, and the coating stability of the sealant is unlikely to be impaired.

(8) Physical properties of sealant The viscosity of the sealant measured by an E-type viscometer at 25°C and 2.5 rpm is preferably 200 Pa·s to 450 Pa·s, and more preferably 250 Pa·s to 400 Pa·s. If the viscosity is within the above range, when a pair of substrates are overlapped by the sealant (sealing pattern), the sealant is easily deformed to fill the gap. Therefore, the gap between a pair of substrates of the liquid crystal display panel can be appropriately controlled.

In addition, from the perspective of the coating properties of the sealant, the thixotropy index (TI (thixotropy index) value) of the sealant is preferably 1.0 to 1.5, and more preferably 1.1 to 1.3. The TI value is obtained by using an E-type viscometer at room temperature (25°C) with the viscosity of the sealant at 0.5 rpm as η1 and the viscosity of the sealant at 5 rpm as η2, and applying these measured values to the following formula (1). TI value = (viscosity η1 at 0.5 rpm (25°C)) / (viscosity η2 at 5 rpm (25°C))···(1)

1-2. Sealing agent for the second liquid crystal dripping method As mentioned above, the sealing components obtained by the previous sealing agent are often: if exposed to a high temperature and high humidity environment, the bonding strength to the substrate is reduced. Moreover, if such a reduction in bonding strength occurs, it is easy to cause undesirable conditions such as liquid crystal leakage. The previous sealing components sometimes have insufficient moisture resistance, and are likely to affect the liquid crystal display panel when or after being exposed to a high temperature and high humidity environment.

In contrast, as described above, it is clear that by adjusting the Young's modulus of the cured product of the sealant to a predetermined range, the sealing member and the substrate can have good bonding strength during or after storage in a high temperature and high humidity environment. Specifically, it is clear that when the initial Young's modulus at 120°C of the film formed by curing the sealant under predetermined conditions is 1.0×10 ⁸ Pa or less, and the difference between the post-PCT Young's modulus at 120°C of the film after storage in a 100% Rh environment for 24 hours and the initial Young's modulus is 8.0×10 ⁷ Pa or less, the sealing member has excellent bonding strength to the substrate even when exposed to a high temperature and high humidity environment. The reason and the method for measuring the Young's modulus are as described in the first sealant.

In the present embodiment, the initial Young's modulus is more preferably 1.0×10 ⁶ Pa to 1.0×10 ⁸ Pa, and more preferably 1.0×10 ⁷ Pa to 5.0×10 ⁷ Pa. In addition, the difference between the Young's modulus after PCT and the initial Young's modulus is more preferably 8.0×10 ⁷ Pa or less, and more preferably 7.0×10 ⁷ Pa or less.

Furthermore, in the present embodiment, the ratio of the amount of active hydrogen derived from the thermosetting agent in the sealant to the amount of epoxy groups derived from the epoxy-based compound in the sealant (the amount of active hydrogen/the amount of epoxy groups) is 0.25 or more. Therefore, the moisture resistance of the obtained sealing component becomes very good. As a reason for this, it can be cited that the amount of active hydrogen is relatively large relative to the amount of epoxy groups. By setting such a ratio, unreacted epoxy groups are less likely to remain after curing, and further, the cross-linking density in the sealing component becomes higher. Therefore, the sealing component is less likely to absorb moisture or allow moisture to pass through.

Furthermore, the number of epoxy groups derived from the epoxy compound is obtained by dividing the amount (mass) of the epoxy compound in the sealant by the epoxy equivalent of the compound. Furthermore, the epoxy equivalent is a value obtained by dividing the molecular weight (or weight average molecular weight) of the epoxy compound by the number of epoxy groups contained in one molecule of the epoxy compound (molecular weight of the epoxy compound/number of epoxy groups). On the other hand, the amount of active hydrogen derived from the thermosetting agent is a value obtained by dividing the amount (mass) of the thermosetting agent in the sealant by the active hydrogen equivalent of the thermosetting agent. The active hydrogen equivalent is a value obtained by dividing the molecular weight (or weight average molecular weight) of the thermosetting agent by the number of active hydrogens bonded to nitrogen atoms contained in one molecule of the thermosetting agent (molecular weight of the thermosetting agent/number of active hydrogens).

Furthermore, when the sealant contains a plurality of epoxy compounds, the number of epoxy groups is calculated for each epoxy compound, and the total value of all of them is used as the number of epoxy groups in the entire sealant. Similarly, when the sealant contains a plurality of thermosetting agents, the number of active hydrogen is calculated for each thermosetting agent, and the total value of all of them is used as the number of active hydrogen in the entire sealant.

The ratio (the number of active hydrogen atoms/the number of epoxy groups) is more preferably 0.25 to 1.0, and further preferably 0.3 to 0.6.

Here, in order to adjust the initial Young's modulus or the post-PCT Young's modulus to the above range, it is only necessary to adjust the composition of the sealant. The components constituting the sealant are described in detail below.

(1) Polymerizable compound The sealant of the present embodiment includes a polymerizable compound having a polymerizable functional group. The polymerizable compound may be a monomer, an oligomer, or a polymer, but is usually a monomer or an oligomer. The sealant of the present embodiment may include only one type of the polymerizable compound, or may include two or more types.

The sealant of the present embodiment at least contains an epoxy compound as a polymerizable compound. In this specification, the epoxy compound is a polymerizable compound having an epoxy group, and the coated particles described below are not included in the epoxy compound. Here, the sealant of the present embodiment also preferably contains a curable monomer represented by the general formula (1).

Examples of epoxy compounds include compounds having an epoxy group and no (meth)acrylic group (hereinafter, also referred to as "epoxy compounds") or compounds having an epoxy group and a (meth)acrylic group (hereinafter, also referred to as "(meth)acrylic-epoxy compounds").

The epoxy compound may be any compound having an epoxy group (except compounds corresponding to the (meth)acrylic acid-epoxy compound described later). The number of epoxy groups contained in one molecule of the epoxy compound is preferably two or more. If the number of epoxy groups in the epoxy compound is two or more, the adhesion between the obtained sealing component and the substrate of the liquid crystal display panel becomes good. Furthermore, the moisture resistance of the obtained sealing component is also easily improved.

The epoxy compound may be in liquid or solid form at room temperature. From the viewpoint of the viscosity of the obtained sealant, the softening point of the epoxy compound is preferably 40°C to 110°C.

The epoxy equivalent of the epoxy compound is preferably 200 to 2000, more preferably 300 to 1000. When the epoxy equivalent is within this range, the ratio of the active hydrogen equivalent of the thermosetting agent to the epoxy equivalent of the epoxy compound can be easily satisfied.

In addition, the epoxy compound can be a monomer, an oligomer, or a polymer. The molecular weight (or weight average molecular weight) of the epoxy compound is generally preferably 220 to 3000, more preferably 250 to 2500, and further preferably 300 to 2000. Among them, relative to the total amount of the epoxy compound, the proportion of components with a molecular weight of 500 or more is preferably 25% by mass or more. Epoxy compounds with a molecular weight of 500 or more are not easily dissolved in liquid crystals when making liquid crystal display panels. Therefore, the display characteristics of the obtained liquid crystal display panel become good. The weight average molecular weight of the epoxy compound can be measured, for example, by gel permeation chromatography (GPC) (polystyrene conversion).

Here, the structure of the epoxy compound is not particularly limited, and examples thereof include aromatic epoxy compounds containing an aromatic ring in the main chain. The structure of the epoxy compound is the same as the epoxy compound contained in the first sealant. The sealant may contain only one epoxy compound, or may contain two or more epoxy compounds.

Here, the total amount of the epoxy compound is preferably 5 mass % to 70 mass %, and more preferably 10 mass % to 50 mass % relative to the total amount of the polymerizable compound. If the amount of the epoxy compound in the polymerizable compound is 5 mass % or more, the bonding strength between the cured sealant and the substrate of the liquid crystal display panel is easily improved. On the other hand, if the amount of the epoxy compound is 70 mass % or less, the unreacted components contained in the obtained sealing member are easily reduced. Therefore, the difference between the post-PCT Young's modulus and the initial Young's modulus of the cured sealant is easily reduced.

On the other hand, the so-called (meth)acrylic-epoxy-containing compound refers to a compound having an epoxy group and a (meth)acrylic group in one molecule. When the polymerizable compound includes the epoxy compound and the curable monomer described later, there is a case where the compatibility of these is low. In contrast, if the polymerizable compound further includes a (meth)acrylic-epoxy-containing compound, the compatibility of the epoxy compound and the curable monomer is improved. Furthermore, the (meth)acrylic-epoxy-containing compound can also be used to suppress the dissolution of the epoxy compound into the liquid crystal.

Here, the specific structure or preferred structure of the (meth)acrylic-epoxy compound is the same as the (meth)acrylic-epoxy compound contained in the first sealant.

Here, the molecular weight (weight average molecular weight) of the (meth)acrylic-epoxy-containing compound is preferably 310 to 1000, more preferably 350 to 900. The weight average molecular weight of the (meth)acrylic-epoxy-containing compound can be measured by gel permeation chromatography (GPC), for example (polystyrene conversion). When the molecular weight of the (meth)acrylic-epoxy-containing compound is within this range, the viscosity of the sealant is likely to be within a desired range.

The total amount of the (meth)acrylic-epoxy-containing compound is preferably 30% to 80% by mass, and more preferably 40% to 70% by mass, relative to the total amount of the polymerizable compound. If the amount of the (meth)acrylic-epoxy-containing compound is 30% by mass or more, the compatibility of the curable monomer and the epoxy compound is easily improved. On the other hand, if the amount of the (meth)acrylic-epoxy-containing compound is 80% by mass or less, the initial Young's modulus or the Young's modulus after PCT is easily within the desired range.

On the other hand, if the polymerizable compound further includes a curable monomer represented by the general formula (1) described in the first sealant, the initial Young's modulus or the post-PCT Young's modulus of the cured product of the sealant is likely to be within the above range.

Here, the molecular weight (or weight average molecular weight) of the curable monomer represented by the general formula (1) is preferably 700 or more, and more preferably 750 to 1300. If the molecular weight (or weight average molecular weight) of the curable monomer is 700 or more, the cured product of the curable monomer becomes soft, and the effect of absorbing the stress generated at the interface between the substrate and the sealing component becomes higher. The molecular weight of the curable monomer can be adjusted according to the number of n, m, or p in the general formula (1), that is, the amount of the structure derived from ethylene oxide or the structure derived from propylene oxide. In addition, the weight average molecular weight of the curable monomer can be measured, for example, by gel permeation chromatography (GPC) (polystyrene conversion).

The total amount of the curable monomer is preferably 10% by mass or more and 30% by mass or less, and more preferably 10% by mass or more and 20% by mass or less relative to the total amount of the polymerizable compound. If the amount of the curable monomer is too much, the display characteristics of the liquid crystal display panel may be affected by the curable monomer. In contrast, if the amount of the curable monomer is 30% by mass or less, the display characteristics of the liquid crystal display panel are likely to be good. On the other hand, if the amount of the curable monomer is 10% by mass or more, the initial Young's modulus and the post-PCT Young's modulus are likely to be within the range.

In addition, the polymerizable compound preferably includes, in addition to the epoxy compound and the curable monomer, a (meth)acrylic compound other than the curable monomer. If the polymerizable compound includes a (meth)acrylic compound, the bonding strength between the substrate and the sealing member is likely to be improved, or the display characteristics of the liquid crystal display panel are likely to be improved.

The (meth)acrylic compound contained in the polymerizable compound of the present embodiment is a compound containing one or more (meth)acrylic groups in one molecule and is a compound without an epoxy group (except for the compound corresponding to the curable monomer). The (meth)acrylic compound may be a monomer, an oligomer, or a polymer.

The number of (meth)acrylic groups contained in one molecule of the (meth)acrylic compound is preferably two or more. When the number of (meth)acrylic groups in the (meth)acrylic compound is two or more, the photocurability of the sealant becomes good.

The (meth)acrylic compound is the same as the (meth)acrylic compound contained in the first sealant. Among the (meth)acrylic compounds, the glass transition temperature of the (meth)acrylic compound is preferably 25°C or more and less than 200°C from the viewpoint that the initial Young's modulus of the cured product of the sealant is easily within the desired range. The glass transition temperature is more preferably 40°C to 200°C, and further preferably 50°C to 150°C. The glass transition temperature can be measured by a viscoelasticity measuring device (DMS).

The molecular weight (or weight average molecular weight) of the (meth)acrylic compound is preferably 310 to 1000, more preferably 400 to 900. The weight average molecular weight of the (meth)acrylic compound can be measured by gel permeation chromatography (GPC), for example (polystyrene conversion). When the molecular weight of the (meth)acrylic compound is within this range, the viscosity of the sealant is likely to be within the desired range.

The amount of the (meth)acrylic compound is preferably 5% to 70% by mass, more preferably 10% to 50% by mass, relative to the total amount of the polymerizable compound. If the amount of the (meth)acrylic compound is 5% by mass or more, the photocurability of the sealant tends to be good. On the other hand, if the amount of the (meth)acrylic compound is 70% by mass or less, the moisture resistance of the obtained sealing member tends to be good.

Furthermore, the total amount of the polymerizable compound (the total amount of the epoxy compound, the (meth)acrylic-epoxy-containing compound, the curable monomer, and the (meth)acrylic compound) is preferably 60% to 80% by mass, and more preferably 65% to 75% by mass, relative to the total amount of the sealant. If the polymerizable compound is contained in the sealant within this range, the curability of the sealant becomes good, and a high-strength sealing member can be obtained.

(2) Thermosetting agent The sealant contains a thermosetting agent. The thermosetting agent is not particularly limited as long as it is a component that can cure the polymerizable compound, especially the epoxy compound or the (meth)acrylic-epoxy group-containing compound, by heating, and the ratio of the amount of active hydrogen derived from the thermosetting agent to the amount of epoxy groups in the sealant is 0.25 or more. Furthermore, the thermosetting agent is preferably a compound that does not cure the epoxy compound or the (meth)acrylic-epoxy group-containing compound under normal storage conditions (room temperature, visible light, etc.), but cures these compounds by heating. A sealant containing such a thermosetting agent can achieve both storage stability and thermosetting properties.

The active hydrogen equivalent of the thermosetting agent is preferably 10 to 500, more preferably 100 to 300. When the active hydrogen equivalent of the thermosetting agent is within this range, the ratio of the amount of active hydrogen derived from the thermosetting agent to the amount of epoxy groups in the sealant can be easily satisfied.

As the thermosetting agent, the same epoxy curing agent as the epoxy curing agent contained in the first sealant is preferred. From the viewpoint of improving the viscosity stability of the sealant without impairing the moisture resistance of the obtained sealing member, the melting point of the epoxy curing agent is preferably 50°C or more and 250°C or less, more preferably 100°C or more and 200°C or less, and further preferably 150°C or more and 200°C or less. If the melting point of the epoxy curing agent is within this range, the sealant can be one-liquid curing. If the sealant is one-liquid curing, it is not necessary to mix the main agent and the curing agent when using it, so the workability is excellent.

The structure of the epoxy curing agent is the same as that of the epoxy curing agent contained in the first sealant. Among the epoxy curing agents, imidazole-based heat latent curing agents, amine adduct-based heat latent curing agents, or polyamine-based heat latent curing agents are preferred from the viewpoints of availability, compatibility with other components, etc. The sealant may contain only one epoxy curing agent, or may contain two or more.

The content of the thermosetting agent is preferably 1 mass % to 20 mass %, more preferably 2 mass % to 18 mass %, and further preferably 3 mass % to 15 mass % relative to the total amount of the sealant. When the amount of the thermosetting agent is within this range, the thermosetting property of the sealant becomes good.

(3) Curing Catalyst In addition, the sealant preferably contains a curing catalyst. The curing catalyst may be a compound that functions as a catalyst when the polymerizable compound is polymerized or crosslinked. Examples of the curing catalyst include imidazole-based curing catalysts, amine adduct-based curing catalysts, and modified amine-based curing catalysts.

Examples of imidazole-based curing catalysts include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-hydroxymethylimidazole, 1-benzyl-5-hydroxymethylimidazole, 1,2-dihydroxyethylimidazole, and a mixture of 1,3,5-triazine-2,4,6(1H,3H,5H)-trione and 6-[2-(2-methyl-1H-imidazol-1-yl)ethyl]-1,3,5-triazine-2,4-diamine.

Examples of amine adduct-based curing catalysts include Amicure PN-23 (manufactured by Ajinomoto Seika Chemicals Co., Ltd.). Examples of modified amine-based curing catalysts include Fujicure FXR-1020, FXR-1081, FXR-1121, FXR-1032, and FXR-1131 (all manufactured by Fuji Chemical Industries, Ltd.).

Among the above, the melting point of the curing catalyst is preferably 100° C. or higher, and more preferably 140° C. to 300° C. When the melting point of the curing catalyst is 100° C. or higher, the storage stability of the sealant tends to be good.

The content of the hardening catalyst is preferably 0.1 mass % to 20 mass %, more preferably 0.2 mass % to 15 mass %, and further preferably 0.3 mass % to 13 mass % relative to the total amount of the sealant. When the amount of the hardening catalyst is within this range, the sealant is well hardened.

(4) Coated particles The sealant preferably further comprises coated particles. The coated particles in this specification are particles having a core comprising inorganic particles and a polymer layer covering the core, and refer to particles having functional groups comprising epoxy groups and/or carbon-carbon double bonds on the surface. Examples of carbon-carbon double bonds include vinyl groups, allyl groups, and (meth)acrylic groups.

The polymer layer may cover the entire core or only a portion thereof, wherein the coverage is preferably 50% or more, more preferably 80% or more.

In addition, when the coated particles have epoxy groups on their surfaces, the amount of epoxy groups per 1 g of coated particles is preferably 1 μeq/g to 300 μeq/g. From the viewpoint of storage stability, the value is preferably 1 μeq/g to 150 μeq/g. From the viewpoint of improving bonding strength, the value is preferably 5 μeq/g to 300 μeq/g. The amount of epoxy groups can be specified by a known measurement method.

In addition, when the surface of the coated particles has a functional group containing a carbon-carbon double bond, the amount of the functional group having a carbon-carbon double bond per 1 g of the coated particles is preferably 1 μeq/g to 300 μeq/g. Within this range, the storage stability of the sealant becomes good. The method for determining the equivalent of the functional group having a carbon-carbon double bond is not particularly limited, and as an example, the iodine value method (General Testing Methods 65. Oil and Fats Testing Method, Fourteenth Revision of the Japanese Pharmacopoeia) can be cited.

In addition, the average particle size of the coated particles is preferably 0.2 μm to 10 μm, more preferably 0.2 μm to 5 μm, and further preferably 0.2 μm to 3 μm. In addition, the thickness of the polymer layer in the coated particles is preferably 0.001 μm to 1 μm, and more preferably 0.001 μm to 0.5 μm. If the thickness of the polymer layer is within this range, the affinity between the coated particles and the polymerizable compound is improved, not only the coating property of the sealant becomes good, but also the deformation of the obtained sealing component can be suppressed. The thickness of the polymer layer can be specified based on the average particle size of the core and the average particle size of the coated particles. Specifically, it can be calculated in the form of average thickness of the polymer layer = (average particle size of the coated particles - average particle size of the core)/2. The average particle size of the core and the average particle size of the coated particles can be determined by a laser particle size measuring device using a laser with a wavelength of 632.8 nm, and is taken as the average value when the average particle size of the primary particles is measured 10 times.

Examples of the core of the coated particles include crystalline silica, fused silica, silica obtained by a precipitation method, silica obtained by a sol-gel method, calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, zirconium dioxide, iron oxide, titanium oxide, alumina, zinc oxide, silica, titanium dioxide, potassium titanium oxide, kaolin, talc, silicon nitride, boron nitride, aluminum nitride, quartz powder, mica, glass fiber, etc.; composite oxides of silica and other metals such as silica and titanium oxide, silica and zirconium oxide, etc. Among these, more preferred are crystalline silica, fused silica, silica obtained by a sol-gel method, and the like having excellent thermal stability. The core may be subjected to a hydrophobic treatment.

Examples of the hydrophobic treatment include a method of treating the core material with a hydrophobic surface treatment agent such as cyclic siloxane, silane coupling agent, titanium ester coupling agent, hexaalkyldisilazane, etc. Among these, if the hydrophobic treatment is performed with a cyclic siloxane such as hexamethylcyclotrisiloxane or a hexaalkyldisilazane such as hexamethyldisilazane, the hygroscopicity of the obtained sealing member is likely to be reduced.

On the other hand, the polymer layer can be formed by free radical polymerization of a monomer having a free radical polymerizable functional group in the presence of the core. For example, a monomer having a free radical polymerizable functional group (such as an acrylate epoxy ester having a carbon-carbon double bond or a multifunctional carbon-carbon double bond compound) can be sprayed on the core to attach the monomer to the surface of the core, and then the monomer is free radically polymerized to form a polymer layer. In addition, the functional group on the core can be grafted with a monomer having a free radical polymerizable functional group (such as an acrylate epoxy ester having a carbon-carbon double bond or a multifunctional carbon-carbon double bond compound) by a dehydration condensation reaction, thereby forming a polymer layer. In addition, a method of reacting a compound having a carbon-carbon double bond such as an acrylic silane compound with a core and then further reacting the core with a monomer having a free radical polymerizable functional group (an acrylic epoxy ester having a carbon-carbon double bond or a multifunctional carbon-carbon double bond compound) to form a core layer is particularly preferred. Furthermore, in this specification, a polymer obtained by polymerizing a multifunctional carbon-carbon double bond compound is referred to as a crosslinked polymer. The polymer layer preferably includes a crosslinked polymer.

Furthermore, when forming the polymer layer, an acrylate epoxy ester or a multifunctional carbon-carbon double bond compound having a carbon-carbon double bond as a monomer having a free radical polymerizable functional group and a thermosetting agent or a photopolymerization initiator may also be used together. These may be the same as the thermosetting agent or photopolymerization initiator contained in the sealant. In addition, the amount thereof may also be appropriately selected according to the desired polymer layer.

Examples of the acrylic silane compound that reacts with the core when forming the polymer layer include methacryloxypropyltrimethoxysilane, 3-methacryloxymethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-acryloxypropyltrimethoxysilane.

Examples of the epoxy acrylate used in forming the polymer layer include glycidyl (meth)acrylate, glycidyloxystyrene, glycidyloxymethylstyrene, glycidyloxyethylstyrene, and the like.

In addition, the polyfunctional carbon-carbon double bond compound used in forming the polymer layer is a compound having two or more carbon-carbon double bonds, and examples thereof include aromatic vinyl monomers such as polyfunctional aromatic vinyl compounds such as divinylbenzene, divinylbiphenyl, trivinylbenzene, and divinylnaphthalene; polyfunctional (meth)acrylic monomers such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trihydroxymethylmethane tri(meth)acrylate, tetrahydroxymethylmethane tetra(meth)acrylate, and hexamethylenedi(meth)acrylamide; (meth)allyl (meth)acrylate, etc. Furthermore, in order to allow carbon-carbon double bonds to remain on the surface of the particles, the amount of the photopolymerization initiator may be controlled. Furthermore, even when monomers having a plurality of functional groups with different reactivities are combined, a portion of the carbon-carbon double bonds can remain on the surface.

In addition, monomers other than epoxy acrylate or multifunctional carbon-carbon dibond compounds may be used in combination when forming the polymer layer. Examples of other monomers include aromatic vinyl monomers such as styrene, vinyl toluene, 2,4-dimethylstyrene, tert-butylstyrene, and vinyl naphthalene; (meth)acrylic monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and (meth)acrylonitrile; divinyl sulfide, ethyl vinyl ether, methyl vinyl ketone, and vinyl pyrrolidone.

The content of the coated particles is preferably 0.1 mass % to 30 mass %, more preferably 3 mass % to 20 mass %, and further preferably 5 mass % to 20 mass % relative to the total amount of the sealant. When the amount of the coated particles is within this range, the moisture resistance of the sealant becomes good.

(5) Photopolymerization initiator The sealant preferably contains a photopolymerization initiator. The photopolymerization initiator may be any compound that can generate active species by irradiation with light, and may be a self-cleaving type photopolymerization initiator or a dehydrogenating type photopolymerization initiator. The sealant may contain only one type of photopolymerization initiator or may contain two or more types.

Specific examples of the photopolymerization initiator contained in the sealant of this embodiment are the same as the photopolymerization initiator contained in the first sealant.

The absorption wavelength of the photopolymerization initiator is not particularly limited, and for example, a photopolymerization initiator that absorbs light with a wavelength of 360 nm or more is preferred. Among them, a photopolymerization initiator that absorbs light in the visible light region is more preferred, and a photopolymerization initiator that absorbs light with a wavelength of 360 nm to 780 nm is further preferred, and a photopolymerization initiator that absorbs light with a wavelength of 360 nm to 430 nm is particularly preferred.

Examples of photopolymerization initiators that absorb light with a wavelength of 360 nm or more include alkyl phenoxide compounds, acyl phosphine oxide compounds, titanocene compounds, oxime ester compounds, thioxanthrone compounds, and anthraquinone compounds, preferably alkyl phenoxide compounds or oxime ester compounds. The structure of the photopolymerization initiator can be specified using the above method.

The molecular weight of the photopolymerization initiator is preferably, for example, 200 or more and 5000 or less. If the molecular weight of the photopolymerization initiator is 200 or more, the photopolymerization initiator is not easily dissolved into the liquid crystal when the sealant contacts the liquid crystal. On the other hand, if the molecular weight is 5000 or less, the compatibility with the (meth) acrylic acid compound and the like is improved, and the curability of the sealant is easily improved. The molecular weight of the photopolymerization initiator is more preferably 230 or more and 3000 or less, and further preferably 230 or more and 1500 or less. The molecular weight of the photopolymerization initiator can be obtained using the method described above.

The amount of the photopolymerization initiator relative to the total amount of the sealant is preferably 0.1 mass % to 15 mass %, more preferably 0.5 mass % to 10 mass %, and further preferably 1 mass % to 10 mass %. If the amount of the photopolymerization initiator is 0.1 mass % or more, the photocurability of the sealant is easily improved. If the amount of the photopolymerization initiator is 15 mass % or less, the photopolymerization initiator is not easily eluted into the liquid crystal.

(6) Organic particles The sealant may further contain organic particles as needed. If the sealant contains organic particles, it is easy to adjust the Young's modulus of the sealant.

Examples of organic particles include silicone particles, acrylic particles, styrene particles such as styrene-divinylbenzene copolymers, and polyolefin particles. The sealant may contain only one type of organic particles or two or more types. The average primary particle size of the organic particles is preferably 0.05 μm to 13 μm, more preferably 0.1 μm to 10 μm, and even more preferably 0.1 μm to 8 μm.

The shape of the organic particles is not particularly limited, but preferably spherical, more preferably round. Spherical means that the ratio of the minimum diameter (b) to the maximum diameter (a) of each particle is b/a = 0.9 to 1.0. The average primary particle diameter of the organic particles can be determined by the above method.

The content of the organic particles is preferably 0.1 mass % to 20 mass %, more preferably 1 mass % to 15 mass %, and further preferably 3 mass % to 13 mass % relative to the total amount of the sealant. When the amount of the organic particles is within this range, the elastic modulus of the sealant after light curing is likely to be within a desired range.

(7) Inorganic particles The sealant may further contain inorganic particles. If the sealant contains inorganic particles, the viscosity of the sealant and the strength and linear expansion of the obtained sealing member are likely to be improved.

Specific examples of the inorganic particles contained in the sealant of this embodiment are the same as the inorganic particles contained in the first sealant.

The content of the inorganic particles is preferably 0.1 mass % to 25 mass %, more preferably 3 mass % to 20 mass %, and even more preferably 5 mass % to 18 mass % relative to the total amount of the sealant. If the content of the inorganic particles is 0.1 mass % or more, the moisture resistance of the obtained sealing member is easily improved, and if it is 25 mass % or less, the coating stability of the sealant is not easily impaired.

(8) Others The sealant of this embodiment may further include additives such as thermal free radical polymerization initiators, coupling agents such as silane coupling agents, ion scavengers, ion exchange agents, leveling agents, pigments, dyes, sensitizers, plasticizers, and defoaming agents as needed.

Examples of silane coupling agents include vinyl trimethoxysilane, γ-(meth)acryloxypropyl trimethoxysilane, γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropyl triethoxysilane, etc. The amount of the silane coupling agent is preferably 0.01 mass% to 6 mass%, more preferably 0.1 mass% to 5 mass%, and further preferably 0.5 mass% to 3 mass% relative to the total amount of the sealant. If the content of the silane coupling agent is 0.01 mass% or more, the obtained sealing component is likely to have sufficient adhesion.

The sealant may further include spacers for adjusting the gap of the liquid crystal display panel.

The total amount of other components is preferably 1 mass % to 50 mass % relative to the total amount of the sealant. If the total amount of other components is 50 mass % or less, the viscosity of the sealant is unlikely to increase excessively, and the coating stability of the sealant is unlikely to be impaired.

(9) Physical properties of sealant The viscosity of the sealant measured by an E-type viscometer at 25°C and 2.5 rpm is preferably 200 Pa·s to 450 Pa·s, and more preferably 250 Pa·s to 400 Pa·s. If the viscosity is within the above range, when a pair of substrates are overlapped by the sealant (sealing pattern), the sealant is easily deformed to fill the gap. Therefore, the gap between a pair of substrates of the liquid crystal display panel can be appropriately controlled.

In addition, from the perspective of the coating properties of the sealant, the flexural index (TI value) of the sealant is preferably 1.0 to 1.5, and more preferably 1.1 to 1.3. The TI value is obtained by using an E-type viscometer at room temperature (25°C) with the viscosity of the sealant at 0.5 rpm as η1 and the viscosity of the sealant at 5 rpm as η2, and applying these measured values to the following formula (1). TI value = (viscosity η1 at 0.5 rpm (25°C)) / (viscosity η2 at 5 rpm (25°C))···(1)

2. Liquid crystal display panel The liquid crystal display panel of the present invention has a pair of substrates, a frame-shaped sealing member disposed between the substrates, and liquid crystal filled between the pair of substrates and inside the frame-shaped sealing member. In the liquid crystal display panel, the sealing member is a cured product of the sealant. The sealing member obtained by the first sealant or the second sealant has a high bonding strength with the substrate, and even if the sealing member is thinned, liquid crystal leakage is not likely to occur. Furthermore, the sealant is not likely to contaminate the liquid crystal. Therefore, when the liquid crystal display panel is used, afterimages are not likely to occur.

A pair of substrates (also referred to as "display substrate and counter substrate") are both transparent substrates. Examples of materials for the transparent substrates include glass, polycarbonate, polyethylene terephthalate, polyether ether, and polymethyl methacrylate (PMMA).

A matrix-shaped thin film transistor (TFT), a color filter, a black matrix, etc. are arranged on the surface of the display substrate or the counter substrate. An alignment film is further formed on the surface of the display substrate or the counter substrate. The alignment film contains a known organic alignment agent or an inorganic alignment agent, etc. In addition, the liquid crystal can use a known liquid crystal.

There are generally two methods for manufacturing a liquid crystal display panel: a liquid crystal dropping method and a liquid crystal injection method. However, the method for manufacturing a liquid crystal display panel of the present invention is preferably the liquid crystal dropping method.

The manufacturing method of a liquid crystal display panel using a liquid crystal dropping method includes: 1) a sealing pattern forming step, in which the sealing agent is applied on one of the substrates to form a frame-shaped sealing pattern; 2) a liquid crystal dropping step, in which, when the sealing pattern is not hardened, liquid crystal is dropped on one of the substrates and in an area surrounded by the sealing pattern, or on another substrate and in an area surrounded by the sealing pattern when the other substrate is facing the one of the substrates; 3) an overlapping step, in which one of the substrates and the other substrate are overlapped with each other via the sealing pattern; and 4) a curing step, in which the sealing pattern is cured.

1) In the sealing pattern forming step, the sealant is applied on one of the substrates. The method of applying the sealant is not particularly limited, and any method that can form a sealing pattern with a desired thickness or width, such as screen printing or application using a dispenser, is not particularly limited, and is the same as the known method of applying the sealant.

In addition, the shape of the sealing pattern formed can be appropriately selected according to the purpose of the liquid crystal display panel, as long as it is a shape that does not leak liquid crystal. For example, it can be set to a rectangular frame shape, but it is not limited to this shape. The line width of the sealing pattern is preferably 0.2 mm to 1.0 mm, and more preferably 0.2 mm to 0.5 mm.

2) In the liquid crystal dropping step, a pair of substrates are placed facing each other in a state where the sealing pattern is not hardened. Here, the state where the sealing pattern is not hardened refers to a state where the curing reaction of the sealant has not proceeded to the gelation point. Furthermore, before the liquid crystal dropping step, in order to suppress the dissolution of the sealant in the liquid crystal, the sealing pattern may be irradiated with light or heated to semi-harden it. In addition, the liquid crystal dropping method is the same as the known liquid crystal dropping method, and the liquid crystal may be dropped on a substrate with a sealing pattern formed thereon, or on a substrate (another substrate) without a sealing pattern formed thereon.

3) In the overlapping step, one substrate is overlapped with the other substrate in a manner of facing each other through the sealing pattern. At this time, the gap between the substrates is controlled in a manner to be within a desired range.

4) In the curing step, the sealing pattern is cured. There is no particular limitation on the curing method of the sealing pattern, but it is preferably temporarily cured by irradiation with light of a specified wavelength and then formally cured by heating. The sealing pattern can be cured instantly by light irradiation, and the components in the sealant can be suppressed from dissolving in the liquid crystal.

The wavelength of the irradiated light can be appropriately selected according to the type of photopolymerization initiator, and light containing visible light is preferred. In addition, the light irradiation time also depends on the composition of the sealant, and is, for example, about 10 minutes. At this time, the irradiated energy can be an energy of a degree that can cure the (meth) acrylic compound or the (meth) acrylic-epoxy-containing compound.

After irradiation with light, the epoxy compound or the (meth)acrylic-epoxy-containing compound can be cured by heating. The heating temperature also depends on the composition of the sealant, but is, for example, 100°C to 150°C, and the heating time is preferably about 2 hours. [Example]

The present invention is described in detail based on the embodiments, but the present invention is not limited to these embodiments.

1. First embodiment [Synthesis Example 1] Synthesis of curable monomer (A-1) 228 g of liquid bisphenol A (manufactured by Fuji Film and Koshun Chemical Co., Ltd.) and 0.74 g of catalyst (potassium hydroxide, manufactured by Fuji Film and Koshun Chemical Co., Ltd.) were placed in a high-pressure reactor (autoclave) equipped with a stirrer and replaced with nitrogen. Next, the high-pressure reactor was heated while stirring, and when the internal temperature reached 70°C, 440 g of ethylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was pressure-charged into the high-pressure reactor, and then heated to 100°C and half-reacted for 4 hours. After the reaction, the temperature was cooled to 23°C, and the bisphenol A type ethoxylate was separated. 316 g of the obtained bisphenol A type ethoxylate and 144 g of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a flask, and dry air was introduced, and the mixture was stirred under reflux at 105°C for 20 hours. The obtained compound was washed 20 times with ultrapure water to obtain a curable monomer (A-1) (ethylene oxide (EO) modified bisphenol A type acrylic acid monomer (m+n+p=10 in the general formula (1)) satisfying the structure of the general formula (1). The average molecular weight is shown in Table 1.

[Synthesis Example 2] Synthesis of curable monomer (A-2) 228 g of liquid bisphenol A (manufactured by Fuji Film and Koujun Chemical Co., Ltd.) and 0.74 g of catalyst (potassium hydroxide, manufactured by Fuji Film and Koujun Chemical Co., Ltd.) were placed in a high-pressure reactor (autoclave) equipped with a stirrer and replaced with nitrogen. Next, the high-pressure reactor was heated while stirring, and when the internal temperature reached 70°C, 704 g of ethylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was pressure-charged into the high-pressure reactor, and then heated to 100°C and half-reacted for 4 hours. After the reaction, the temperature was cooled to 23°C, and the bisphenol A type ethoxylate was separated. 316 g of the obtained bisphenol A type ethoxylate and 144 g of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a flask, and dry air was introduced, and the mixture was stirred under reflux at 105°C for 20 hours. The obtained compound was washed 20 times with ultrapure water to obtain a curable monomer (A-2) (ethylene oxide (EO)-modified bisphenol A type acrylic acid monomer (m+n+p=16 in the general formula (1))) having a structure satisfying the general formula (1). The average molecular weight is shown in Table 1.

[Synthesis Example 3] Synthesis of curable monomer (A-3) 228 g of liquid bisphenol A (manufactured by Fuji Film and Koshun Chemical Co., Ltd.) and 0.74 g of catalyst (potassium hydroxide, manufactured by Fuji Film and Koshun Chemical Co., Ltd.) were placed in a high-pressure reactor (autoclave) equipped with a stirrer and replaced with nitrogen. Next, the high-pressure reactor was heated while stirring, and when the internal temperature reached 70°C, 440 g of ethylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was pressure-charged into the high-pressure reactor, and then heated to 100°C and half-reacted for 4 hours. After the reaction, the temperature was cooled to 23°C, and the bisphenol A type ethoxylate was separated. 316 g of the obtained bisphenol A ethoxylate and 200 g of methacrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a flask, and dry air was introduced, and the mixture was reacted for 20 hours under reflux stirring at 105°C. The obtained compound was washed 20 times with ultrapure water to obtain a curable monomer (A-3) (ethylene oxide (EO)-modified bisphenol A methacrylic acid monomer (m+n+p=10 in the general formula (1)) satisfying the structure of the general formula (1). The average molecular weight is shown in Table 1.

[Synthesis Example 4] Synthesis of curable monomer (A-4) 200 g of liquid bisphenol F (manufactured by Fuji Film and Koshun Chemical Co., Ltd.) and 0.74 g of catalyst (potassium hydroxide, manufactured by Fuji Film and Koshun Chemical Co., Ltd.) were placed in a high-pressure reactor (autoclave) equipped with a stirrer and replaced with nitrogen. Next, the high-pressure reactor was heated while stirring, and when the internal temperature reached 70°C, 440 g of ethylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was pressure-charged into the high-pressure reactor, and then heated to 100°C and half-reacted for 4 hours. After the reaction, the temperature was cooled to 23°C, and the bisphenol F type ethoxylate was separated. 288 g of the obtained bisphenol F type ethoxylate and 144 g of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a flask, and dry air was introduced, and the mixture was reacted for 20 hours under reflux stirring at 105°C. The obtained compound was washed 20 times with ultrapure water to obtain a curable monomer (A-4) (EO-modified bisphenol F type acrylic monomer (m+n+p=10 in the general formula (1)) satisfying the structure of the general formula (1). The weight average molecular weight is shown in Table 1.

[Synthesis Example 5] Synthesis of curable monomer (A-5) 200 g of liquid bisphenol F (manufactured by Fuji Film and Koshun Chemical Co., Ltd.) and 0.74 g of catalyst (potassium hydroxide, manufactured by Fuji Film and Koshun Chemical Co., Ltd.) were placed in a high-pressure reactor (autoclave) equipped with a stirrer and replaced with nitrogen. Next, the high-pressure reactor was heated while stirring, and when the internal temperature reached 70°C, 440 g of ethylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was pressure-charged into the high-pressure reactor, and then heated to 100°C and half-reacted for 4 hours. After the reaction, the temperature was cooled to 23°C, and the bisphenol F type ethoxylate was separated. 288 g of the obtained bisphenol F type ethoxylate and 200 g of methacrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a flask, and dry air was introduced, and the mixture was reacted for 20 hours under reflux stirring at 105°C. The obtained compound was washed 20 times with ultrapure water to obtain a curable monomer (A-5) (EO-modified bisphenol F type methacrylic acid monomer (m+n+p=10 in the general formula (1)) satisfying the structure of the general formula (1). The weight average molecular weight is shown in Table 1.

[Synthesis Example 6] Synthesis of curable monomer (A-6) 456 g of liquid bisphenol A (manufactured by Fuji Film and Koshun Chemical Co., Ltd.) and 0.74 g of catalyst (potassium hydroxide, manufactured by Fuji Film and Koshun Chemical Co., Ltd.) were placed in a high-pressure reactor (autoclave) equipped with a stirrer and replaced with nitrogen. Next, the high-pressure reactor was heated while stirring, and when the internal temperature reached 70°C, 352 g of ethylene oxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was pressure-charged into the high-pressure reactor, and then heated to 100°C and half-reacted for 4 hours. After the reaction, the temperature was cooled to 23°C and the bisphenol A type ethoxylate was separated. 316 g of the obtained bisphenol A type ethoxylate and 144 g of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were placed in a flask, and dry air was introduced, and the mixture was reacted for 20 hours under reflux stirring at 105°C. The obtained compound was washed 20 times with ultrapure water to obtain a curable monomer (A-6) (EO-modified bisphenol A type acrylic acid monomer (m+n+p=4 in the general formula (1)) having a structure satisfying the general formula (1). The weight average molecular weight is shown in Table 1.

[Preparation of other compounds] The following compounds were used as components other than the curable monomer.

·Polymerizable compounds Epoxy compound 1: Epikote 1004 manufactured by JER, softening point 97°C, epoxy equivalent: 900, weight average molecular weight: 1650 Epoxy compound 2: EP-4003S manufactured by ADEKA, epoxy equivalent: 470, weight average molecular weight: 940 Acrylic modified epoxy compound: BAEM-50 manufactured by KSM, epoxy equivalent: around 470 (estimated) Acrylic compound: EBECRYL3700 manufactured by Daicel Allnex, weight average molecular weight: 500 Polybutadiene terminal diacrylate: BAC-45 manufactured by Osaka Organic Chemical Industry Co., Ltd., weight average molecular weight: 10000

·Thermohardener Thermohardener 1: EH-4357S manufactured by ADEKA, polyamine type, melting point 75℃～85℃, solubility in water: insoluble, amine equivalent: 0.013 Thermohardener 2: Malonic acid dihydrazide (MDH) manufactured by FINE CHEM, melting point 150℃～160℃, solubility in water: 10 g/100 g, amine equivalent: 0.045

· Photopolymerization initiator Photopolymerization initiator 1: BASF, Irgacure 651 Photopolymerization initiator 2: IGM Regins, Omnipol-TX

·Inorganic particles Manufactured by Admatechs, SO-C1 (silicon dioxide particles)

·(Meth)acrylic thermoplastic polymer particles F351, a microparticle polymer manufactured by Aica Industries

Silane coupling agent Made by Shin-Etsu Chemical Co., Ltd., KBM-403

[Example 1-1] Using three rollers, 100 parts by mass of epoxy compound 2, 495 parts by mass of acrylic modified epoxy compound, 60 parts by mass of acrylic compound, 80 parts by mass of curable monomer (A-1) prepared in Synthesis Example 1, 30 parts by mass of thermosetting agent, 120 parts by mass of inorganic particles, 100 parts by mass of acrylic thermoplastic polymer particles, 10 parts by mass of silane coupling agent, and 10 parts by mass of photopolymerization initiator 1 were fully mixed in a uniform liquid state to obtain a sealing agent for liquid crystal dropping method.

[Example 1-2 to Example 1-10 and Comparative Example 1-1 to Comparative Example 1-5] Except that the type or amount of each component was changed as shown in Table 1, a sealing agent for liquid crystal dropping method was obtained in the same manner as in Example 1-1.

[Evaluation] For the sealants for liquid crystal dropping method obtained in Example 1-1 to Example 1-10 and Comparative Example 1-1 to Comparative Example 1-5, Young's modulus, PCT post-strength and display characteristics were evaluated by the following method.

· Measurement of Young's modulus The obtained sealant for liquid crystal drop method was applied to a release paper with a thickness of 100 μm using an applicator. Then, it was placed in a nitrogen replacement container and flushed with nitrogen for 5 minutes, then irradiated with 3000 mJ/ ^cm2 of light (light calibrated with a wavelength of 365 nm sensor), and then heated at 120°C for 1 hour to prepare a film.

The Young's modulus of the obtained film was measured by cutting the obtained cured film into pieces of 35 mm in length and 10 mm in width using a scissors and heating the film from 25°C to 170°C using a dynamic viscoelasticity measuring device (DMA, DMS6100 manufactured by Seiko Instruments). The value of the storage elastic modulus at 120°C was defined as the initial Young's modulus.

Next, the film prepared in the same manner as above was placed in a PCT tester (manufactured by Hirayama Seisakusho Co., Ltd., PC-422R8D) and exposed to a 121°C, 100% Rh environment for 24 hours. After the temperature was lowered to room temperature, the film was taken out and measured using a dynamic viscoelasticity measuring device in the same manner as above. The value of the storage elastic modulus at 120°C among the obtained results was taken as the Young's modulus after PCT.

· PCT followed by strength evaluation Using a dispenser (Musashi Engineering, Shotmaster), the sealant for the liquid crystal drop method was applied in a 38 mm × 38 mm square (frame shape) on a 40 mm × 45 mm glass substrate (RT-DM88-PIN, EHC) on which a transparent electrode and an alignment film were previously formed, forming a sealing pattern (cross-sectional area 2500 μm ² ). Next, the paired glass substrates were bonded under reduced pressure in a manner perpendicular to the glass substrate on which the sealing pattern was formed, and then bonded by opening the atmosphere. Then, the two bonded glass substrates were kept in a light-shielding box for 1 minute, and then irradiated with 3000 mJ/ ^cm2 of light including visible light (light with a wavelength of 370 nm to 450 nm), and then heated at 120°C for 1 hour to cure the sealant.

Then, the bonded glass substrates were placed in a PCT tester (manufactured by Hirayama Seisakusho Co., Ltd., PC-422R8D), exposed to a 121°C, 100% RH environment for 24 hours, and then taken out after the temperature was lowered to room temperature, thereby obtaining a test piece.

The obtained test piece was pressed vertically at a speed of 5 mm/min at a portion 4.5 mm from the outer periphery of the sealing pattern using an indentation tester (Intesco, Model 210) to measure the stress when the sealant peeled off. The strength was then calculated by dividing the stress by the width of the sealing line drawn with the liquid crystal sealant. Then, the evaluation was performed according to the following criteria. ◎: Peeling occurs when it is 25 N/mm or more ○: Peeling occurs when it is 15 N/mm or more and less than 25 N/mm ×: Peeling occurs when it is less than 15 N/mm

Evaluation of display characteristics Using a dispenser (Shotmaster, manufactured by Musashi Engineering) on a 40 mm × 45 mm glass substrate (RT-DM88-PIN, manufactured by EHC) on which a transparent electrode and an alignment film were previously formed, a 35 mm × 35 mm square (frame-shaped) seal pattern (cross-sectional area 3500 μm ² ) was formed as a main seal using a sealant by the above-mentioned liquid crystal dropping method, and a 38 mm × 38 mm square (frame-shaped) seal pattern was formed on the periphery thereof.

Next, a dispenser is used to precisely drip a liquid crystal material (Merck, MLC-6609-000) of the same volume as the panel after bonding into the frame of the main seal. Next, the paired glass substrates are bonded under reduced pressure and then bonded by opening to the air. The two bonded glass substrates are then kept in a light-shielding box for 1 minute, and then, while shielding the main seal with a 36 mm × 36 mm square substrate coated with a black matrix, 500 mJ/cm ² of visible light (light with a wavelength of 370 nm to 450 nm) is irradiated, and then heated at 120°C for 1 hour to cure the main seal. Then, polarizing films are attached to both sides of the obtained liquid crystal unit to obtain a liquid crystal display panel. The evaluation is performed in the following manner.

○: The liquid crystal is aligned to the edge of the main seal of the LCD panel and there is no color unevenness △: Color unevenness occurs within a range of less than 1 mm near the main seal edge ×: Color unevenness occurs within a range of more than 1 mm near the main seal edge

[Table 1] Embodiment Comparative example Molecular weight 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9 1-10 1-1 1-2 1-3 1-4 1-5 Polymeric compounds Epoxide 1 1650 50 Epoxide 2 940 100 80 80 80 80 80 80 50 80 80 80 80 80 80 80 Acrylic modified epoxy - 495 435 395 515 515 515 515 495 515 535 555 515 515 515 555 Acrylic compounds 500 60 60 60 60 60 60 60 60 60 60 60 60 60 60 60 Hardening Monomer A-1 776 80 160 200 80 80 80 40 80 80 Hardening Monomer A-2 1216 80 Hardening Monomer A-3 806 80 Hardening Monomer A-4 746 80 Hardening Monomer A-5 776 80 Hardening Monomer A-6 512 80 Polybutadiene terminal diacrylate 10000 80 Heat hardener 1 25 25 25 25 25 25 25 25 25 25 25 25 25 25 Heat Hardener 2 25 Inorganic particles 120 120 120 120 120 120 120 120 120 80 120 120 120 120 120 (Meth)acrylic thermoplastic polymer particles 100 100 100 100 100 100 100 100 100 120 100 100 100 100 60 Silane coupling agent 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 Photopolymerization initiator 1 10 10 10 10 10 10 10 10 10 10 10 10 10 10 Photopolymerization initiator 2 10 Initial Young's modulus 1.50E+07 1.20E+07 1.70E+07 1.60E+07 1.60E+07 1.60E+07 1.60E+07 1.90E+07 1.60E+07 1.30E+07 2.00E+07 1.90E+07 1.10E+08 2.60E+07 1.70E+07 Young's modulus after PCT 8.40E+07 8.00E+07 8.40E+07 8.10E+07 8.20E+07 8.30E+07 8.20E+07 8.80E+07 8.20E+07 7.70E+07 1.03E+08 2.30E+08 1.88E+08 1.10E+08 9.90E+07 ΔYoung's modulus 6.90E+07 6.80E+07 6.70E+07 6.50E+07 6.60E+07 6.70E+07 6.60E+07 6.90E+07 6.60E+07 6.40E+07 8.30E+07 2.11E+08 7.80E+07 8.40E+07 8.20E+07 Ratio of curable monomer in polymerizable compound (mass %) 11% twenty two% 27% 11% 11% 11% 11% 11% 11% 11% 5% 11% 11% 0% 10% PCT followed by strength assessment ○ ○ ○ ○ ○ ○ ○ ○ ○ ◎ × × × × × Display feature evaluation ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ × × ○ ○

As shown in Table 1, when the initial Young's modulus was 1.0×10 ⁸ Pa or less and the difference between the Young's modulus after PCT and the initial Young's modulus was 8.0×10 ⁷ Pa or less, the adhesion strength after PCT was high and the display characteristics were good (Example 1-1 to Example 1-10).

On the other hand, when the initial Young's modulus exceeded 1.0×10 ⁸ Pa (Comparative Example 1-3) or the difference between the Young's modulus after PCT and the initial Young's modulus exceeded 8.0×10 ⁷ Pa (Comparative Example 1-1, Comparative Example 1-2, Comparative Example 1-4 and Comparative Example 1-5), the strength after PCT was low. In addition, especially when the curable monomer represented by the general formula (1) was not contained, the exhibited properties were also low (Comparative Example 1-2, Comparative Example 1-3).

2. Second Implementation Form [Synthesis Example 1 to Synthesis Example 6] Synthesis of Hardening Monomer (A-1) to Hardening Monomer (A-6) Each hardening monomer was prepared in the same manner as the synthesis method of the hardening monomer (A-1) to hardening monomer (A-6) of the first implementation form. The average molecular weight is shown in Table 2 and Table 3.

[Synthesis Example 7] Synthesis of coated particles 100 g of sol-gel silica was placed in a 1 L Teflon (registered trademark) three-flask with a stirrer having a Teflon (registered trademark) stirring blade, and a solution of 0.28 g of glycidyl acrylate, 0.026 g of divinylbenzene and 0.04 g of PERBUTYL O (manufactured by NOF Corporation) was sprayed using a two-fluid nozzle while stirring at high speed. After the spraying was completed, stirring was continued for 2 hours. Then, the temperature of the flask was raised to 100°C over 1 hour while stirring, and maintained at 100°C for 4 hours.

The amount of epoxy groups per 1 g of the coated particles obtained in the above manner was measured and found to be 22 μeq/g. Furthermore, the equivalent of the dibond functional group was measured but could not be detected. Based on the results, it was confirmed that the coated particles had epoxy groups on the surface. Furthermore, the thickness of the polymer layer of the coated particles was 0.009 μm.

[Preparation of other compounds] The following compounds are used as components other than the curable monomer and coated particles.

·Polymerizable compounds Epoxy compound 1: Epikote 1004 manufactured by JER, softening point 97°C, epoxy equivalent: 900, weight average molecular weight: 1650 Epoxy compound 2: EP-4003S manufactured by ADEKA, epoxy equivalent: 470, weight average molecular weight: 940 Acrylic modified epoxy compound: BAEM-50 manufactured by KSM, epoxy equivalent: around 470 (estimated) Acrylic compound: EBECRYL3700 manufactured by Daicel Allnex, weight average molecular weight: 500 Polybutadiene terminal diacrylate: BAC-45 manufactured by Osaka Organic Chemical Industry Co., Ltd., weight average molecular weight: 10000

·Thermosetting agent Made by ADEKA, EH-4357S, polyamine type, melting point 75℃～85℃, solubility in water: insoluble, active hydrogen equivalent: 79.75

· Curing catalyst Made by Shikoku Chemical Co., Ltd., Curezol 2MZ-H, melting point 140℃～148℃

· Photopolymerization initiator Made by BASF, Irgacure 651 Made by IGM, Omnipol-TX

·Inorganic particles Manufactured by Admatechs, SO-C1, silicon dioxide particles

·Organic particles Microparticle polymers manufactured by Aica Industries, F351

Silane coupling agent Made by Shin-Etsu Chemical Co., Ltd., KBM-403

[Example 2-1] Using three rollers, 80 parts by mass of epoxy compound 2, 510 parts by mass of acrylic modified epoxy compound, 60 parts by mass of acrylic compound, 80 parts by mass of curable monomer (A-1) prepared in Synthesis Example 1, 30 parts by mass of thermosetting agent, 120 parts by mass of inorganic particles, 100 parts by mass of organic particles, 10 parts by mass of silane coupling agent, and 10 parts by mass of photopolymerization initiator were fully mixed in a uniform liquid state to obtain a sealing agent for liquid crystal dropping method.

[Example 2-2 to Example 2-14 and Comparative Example 2-1 to Comparative Example 2-5] Except for changing the type or amount of each component as shown in Table 2 or Table 3, a sealing agent for liquid crystal dropping method was obtained in the same manner as in Example 2-1.

[Evaluation] For the sealants for the liquid crystal dropping method obtained in Example 2-1 to Example 2-14 and Comparative Example 2-1 to Comparative Example 2-5, Young's modulus, PCT post-strength and display characteristics were evaluated by the following method.

· Measurement of Young's modulus The obtained sealant for liquid crystal drop method was applied to a release paper with a thickness of 100 μm using an applicator. Then, it was placed in a nitrogen replacement container and flushed with nitrogen for 5 minutes, then irradiated with 3000 mJ/ ^cm2 of light (light calibrated with a wavelength of 365 nm sensor), and then heated at 120°C for 1 hour to prepare a film.

The Young's modulus of the obtained film was measured by cutting the obtained cured film into pieces of 35 mm in length and 10 mm in width using a scissors and heating the film from 25°C to 170°C using a dynamic viscoelasticity measuring device (DMA, DMS6100 manufactured by Seiko Instruments). The value of the storage elastic modulus at 120°C was defined as the initial Young's modulus.

Next, the film prepared in the same manner as above was placed in a PCT tester (manufactured by Hirayama Seisakusho Co., Ltd., PC-422R8D) and exposed to a 121°C, 100% Rh environment for 24 hours. After the temperature was lowered to room temperature, the film was taken out and measured using a dynamic viscoelasticity measuring device in the same manner as above. The value of the storage elastic modulus at 120°C among the obtained results was taken as the Young's modulus after PCT.

·Ratio of the amount of active hydrogen in the sealant to the amount of epoxy groups First, the amount of epoxy groups derived from the epoxy compound and the amount of active hydrogen derived from the thermosetting agent are calculated based on the following formula. The number of epoxy groups = (the content of epoxy compound 1/the epoxy equivalent of epoxy compound 1) + (the content of epoxy compound 2/the epoxy equivalent of epoxy compound 2) + (the content of acrylic modified epoxy compound/the epoxy equivalent of the compound) The number of active hydrogen = the content of thermosetting agent/the active hydrogen equivalent of thermosetting agent The value obtained by dividing the number of active hydrogen by the number of epoxy groups (the number of active hydrogen/the number of epoxy groups) is calculated as the ratio of the number of active hydrogen derived from the thermosetting agent in the sealant to the number of epoxy groups derived from the epoxy-based compound in the sealant.

· PCT followed by strength evaluation Using a dispenser (Musashi Engineering, Shotmaster), the sealant for the liquid crystal drop method was applied in a 38 mm × 38 mm square (frame shape) on a 40 mm × 45 mm glass substrate (RT-DM88-PIN, EHC) on which a transparent electrode and an alignment film were previously formed, forming a sealing pattern (cross-sectional area 2500 μm ² ). Next, the paired glass substrates were bonded under reduced pressure in a manner perpendicular to the glass substrate on which the sealing pattern was formed, and then bonded by opening the atmosphere. Then, the two bonded glass substrates were kept in a light-shielding box for 1 minute, and then irradiated with 3000 mJ/ ^cm2 of light including visible light (light with a wavelength of 370 nm to 450 nm), and then heated at 120°C for 1 hour to cure the sealant.

Then, the bonded glass substrates were placed in a PCT tester (manufactured by Hirayama Seisakusho Co., Ltd., PC-422R8D), exposed to a 121°C, 100% RH environment for 24 hours, and then taken out after the temperature was lowered to room temperature, thereby obtaining a test piece.

The obtained test piece was pressed vertically at a speed of 5 mm/min at a portion 4.5 mm from the outer periphery of the sealing pattern using an indentation tester (Intesco, Model 210) to measure the stress when the sealant peeled off. The strength was then calculated by dividing the stress by the width of the sealing line drawn with the liquid crystal sealant. Then, the evaluation was performed according to the following criteria. ◎: Peeling occurs when it is 25 N/mm or more ○: Peeling occurs when it is 15 N/mm or more and less than 25 N/mm ×: Peeling occurs when it is less than 15 N/mm

· Evaluation of moisture permeability A hardened film is prepared in the same manner as the measurement of Young's modulus. The hardened film is placed on an aluminum cup filled with calcium chloride (anhydrous) as a moisture absorbent, and an aluminum ring is placed and screwed. Then, the initial mass of the entire aluminum cup is measured. Then, the aluminum cup is placed in a constant temperature bath set at 60°C and 90%Rh and left for 24 hours. Then, the aluminum cup is taken out to measure the mass. The obtained mass is substituted into the calculation formula "Moisture permeability = (mass after test - mass before test) * film thickness / (film area × 100)" to calculate the moisture permeability. The obtained value is evaluated according to the following criteria. ◎: less than 70 g/m ² ○: 70 g/m ² or more and less than 150 g/m ² ×: 150 g/m ² or more

·Viscosity stability evaluation The sealant was drawn into a plastic syringe, and the initial viscosity (viscosity: A) was measured using an E-type viscometer at 25°C and 2.5 rpm. On the other hand, the sealant (syringe) was stored in a constant temperature bath at 23°C for 168 hours, and then the viscosity was measured again (viscosity: B). The viscosity increase rate was calculated using the following formula for the obtained viscosity, and the evaluation was performed according to the following criteria. In addition, the closer the viscosity increase rate is to 100%, the higher the viscosity stability. Viscosity increase rate (%) = B/A×100 ○: Viscosity increase rate is less than 120% ×: Viscosity increase rate exceeds 120%

· Evaluation of coating properties The obtained sealant was filled into a 10 cc syringe, degassed, and then filled into a dispenser (Shotmaster; manufactured by Musashi Engineering). The dispenser was used to coat the glass substrate at a speed of 4 cm per second for drawing. Coating properties were evaluated according to the following criteria. ○: There was no sealant seepage or stringing from the desired drawing line, and the appearance was also good △: There was no such seepage or stringing, but the appearance was poor ×: The such seepage or stringing occurred, and the coating suitability was extremely poor

[Table 2] Example 2-1 Example 2-2 Embodiment 2-3 Embodiment 2-4 Embodiment 2-5 Embodiment 2-6 Embodiment 2-7 Embodiment 2-8 Embodiment 2-9 Embodiment 2-10 Polymeric compounds Epoxide 1 (Epoxide equivalent: 900) 40 Epoxide 2 (Epoxide equivalent: 470) 80 80 80 80 80 80 80 40 80 80 Acrylic modified epoxy compound (epoxy equivalent: 470) 510 500 490 510 510 510 510 510 510 505 Acrylic compounds 60 60 60 60 60 60 60 60 60 60 Polybutadiene terminal diacrylate Hardening monomer (A-1) (Molecular weight: 776) 80 80 80 80 80 80 Hardening monomer (A-2) (Molecular weight: 1216) 80 Hardening monomer (A-3) (Molecular weight: 806) 80 Hardening monomer (A-4) (Molecular weight: 746) 80 Hardening monomer (A-5) (Molecular weight: 776) 80 Hardening monomer (A-6) (Molecular weight: 512) Thermal hardener (active hydrogen equivalent 79.75) 30 40 50 30 30 30 30 30 30 30 Hardening catalyst (melting point 140℃～148℃) 5 Silicon dioxide particles 120 120 120 120 120 120 120 120 120 120 covered particles Microparticle polymer 100 100 100 100 100 100 100 100 100 100 Silane coupling agent 10 10 10 10 10 10 10 10 10 10 Photopolymerization initiator (IRGACURE 651) 10 10 10 10 10 10 10 10 10 Photopolymerization initiator (Omnipol-TX) 10 Initial Young's modulus 1.70E+07 2.20E+07 3.70E+07 1.60E+07 1.60E+07 1.60E+07 1.60E+07 1.90E+07 1.60E+07 2.50E+07 Young's modulus after PCT 8.40E+07 9.10E+07 1.06E+08 8.10E+07 8.20E+07 8.30E+07 8.20E+07 8.80E+07 8.20E+07 9.10E+07 ΔYoung's modulus 6.70E+07 6.90E+07 6.90E+07 6.50E+07 6.60E+07 6.70E+07 6.60E+07 6.90E+07 6.60E+07 6.60E+07 The ratio of the number of active hydrogen groups to the number of epoxy groups in the sealant 0.30 0.41 0.52 0.30 0.30 0.30 0.30 0.31 0.30 0.30 The amount of curable monomer relative to the total amount of polymerizable compound 11% 11% 11% 11% 11% 11% 11% 11% 11% 11% Then the strength evaluation ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Moisture permeability evaluation ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Viscosity stability evaluation ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Applicability evaluation ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

[Table 3] Embodiment 2-11 Embodiment 2-12 Embodiment 2-13 Embodiment 2-14 Comparative example 2-1 Comparative example 2-2 Comparative example 2-3 Comparative example 2-4 Comparative example 2-5 Polymeric compounds Epoxide 1 (Epoxide equivalent: 900) Epoxide 2 (Epoxide equivalent: 470) 80 80 80 80 80 80 80 80 80 Acrylic modified epoxy compound (epoxy equivalent: 470) 500 510 430 500 550 510 510 520 517 Acrylic compounds 60 60 60 60 60 60 60 60 60 Polybutadiene terminal diacrylate 80 Hardening monomer (A-1) (Molecular weight: 776) 80 80 80 80 40 80 80 Hardening monomer (A-2) (Molecular weight: 1216) Hardening monomer (A-3) (Molecular weight: 806) Hardening monomer (A-4) (Molecular weight: 746) Hardening monomer (A-5) (Molecular weight: 776) Hardening monomer (A-6) (Molecular weight: 512) 80 Thermal hardener (active hydrogen equivalent 79.75) 30 30 30 30 30 30 30 20 20 Hardening catalyst (melting point 140℃～148℃) 10 10 3 Silicon dioxide particles 120 120 120 120 120 120 covered particles 120 200 120 Microparticle polymer 100 100 100 100 100 100 100 100 100 Silane coupling agent 10 10 10 10 10 10 10 10 10 Photopolymerization initiator 10 10 10 10 10 10 10 10 10 Initial Young's modulus 3.20E+07 1.80E+07 1.90E+07 3.30E+07 2.00E+07 2.60E+07 1.90E+07 1.80E+07 1.80E+07 Young's modulus after PCT 9.60E+07 8.10E+07 8.30E+07 9.50E+07 1.03E+08 1.10E+08 2.30E+08 9.90E+07 9.70E+07 ΔYoung's modulus 6.40E+07 6.30E+07 6.40E+07 6.20E+07 8.30E+07 8.40E+07 2.11E+08 8.10E+07 7.90E+07 The ratio of the number of active hydrogen groups to the number of epoxy groups in the sealant 0.30 0.30 0.35 0.30 0.28 0.30 0.30 0.20 0.20 The amount of curable monomer relative to the total amount of polymerizable compound 11% 11% 12% 11% 5% 0% 11% 11% 11% Then the strength evaluation ◎ ◎ ◎ ◎ × × × × ○ Moisture permeability evaluation ◎ ○ ◎ ◎ ○ ○ × × × Viscosity stability evaluation ○ ○ ○ ○ ○ ○ ○ ○ ○ Applicability evaluation ○ ○ ○ ○ ○ ○ ○ ○ ○

As shown in Tables 2 and 3, when the initial Young's modulus is 1.0×10 ⁸ Pa or less, the difference between the Young's modulus after PCT and the initial Young's modulus is 8.0×10 ⁷ Pa or less, and the ratio of the active hydrogen equivalent of the thermosetting agent to the epoxy equivalent of the epoxy compound is 0.25 or more, the adhesion strength after PCT is evaluated to be high and the moisture permeability is also low. Furthermore, the viscosity stability and coating properties are also evaluated to be good (Example 2-1 to Example 2-15). In addition, especially in the case of containing a curing catalyst having a melting point of 100°C or more (Example 2-11 and Example 2-14), the adhesion strength is particularly high and the moisture permeability is also low. In addition, when coated particles are included, the strength is also improved and the moisture permeability is reduced (Example 2-12 to Example 2-14).

On the other hand, when the difference between the post-PCT Young's modulus and the initial Young's modulus exceeded 8.0×10 ⁷ Pa (Comparative Examples 2-1 to 2-4), the post-PCT strength was low. In addition, when the ratio of the amount of active hydrogen derived from the thermosetting agent in the sealant to the amount of epoxy groups derived from the epoxy compound in the sealant was less than 0.25, the moisture permeability evaluation was low (Comparative Examples 2-4 and 2-5).

This application claims priority based on Japanese Patent Application No. 2020-060596 filed on March 30, 2020 and Japanese Patent Application No. 2020-060603 filed on March 30, 2020. All contents described in the specifications of those applications are incorporated herein by reference. [Industrial Applicability]

The cured product of the sealant of the present invention has high bonding strength with the substrate even after being stored in a high temperature and high humidity environment. Therefore, the sealant is very useful as a sealant for manufacturing sealing components of various liquid crystal display panels.

without

without

Claims (15)

A sealing agent for a liquid crystal dropping method, comprising a polymerizable compound having a polymerizable functional group, wherein the sealing agent for a liquid crystal dropping method is used in a liquid crystal dropping method, and in the sealing agent for a liquid crystal dropping method, the polymerizable compound comprises a curable monomer having a structure represented by the following general formula (1), and a (meth)acrylic acid group-epoxy group-containing compound having an epoxy group and a (meth)acrylic acid group in one molecule, the amount of the curable monomer is 10 mass % or more and 30 mass % or less relative to the total amount of the polymerizable compound, and the amount of the (meth)acrylic acid group-epoxy group-containing compound is 30 mass % or more and 70 mass % or less relative to the total amount of the polymerizable compound,

(R ₁ in the general formula (1) represents a

The groups (* represents a bond), _R2 and _R3 each independently represent a group selected from

The group (* represents a bond, m, n and p represent integers of 1 to 30), _R4 and _R5 each independently represent a hydrogen atom or a methyl group), when the sealant for the liquid crystal dropping method is formed into a film with a thickness of 100 μm, irradiated with 3000 mJ/ ^cm2 of light and heated at 120°C for 1 hour to form a film, the initial Young's modulus of the film at 120°C measured by a dynamic viscoelasticity measuring device is 1.0×10 ⁸ Pa or less, and after the film is stored in an environment of 121°C and 100% Rh for 24 hours, the difference between the Young's modulus of the film after the pressure pot test at 120°C measured by the dynamic viscoelasticity measuring device and the initial Young's modulus is 8.0×10 ⁷ Pa or less. The sealant for liquid crystal dripping method as described in claim 1, wherein the molecular weight of the curable monomer is 700 or more. The sealant for liquid crystal dripping method as described in claim 1 further comprises (meth)acrylic thermoplastic polymer particles, and the amount of the (meth)acrylic thermoplastic polymer particles is 10% by mass or more. The sealant for liquid crystal dripping method as described in claim 1 further comprises at least one thermosetting agent selected from the group consisting of imidazole-based thermosetting agents, amine adduct-based thermosetting agents, and polyamine-based thermosetting agents. A sealing agent for a liquid crystal dropping method, comprising a polymerizable compound having a polymerizable functional group and a thermosetting agent, wherein the polymerizable compound in the sealing agent for a liquid crystal dropping method comprises a curable monomer having a structure represented by the following general formula (1), and an epoxy compound of a (meth)acrylic acid group-epoxy group-containing compound having an epoxy group and a (meth)acrylic acid group in one molecule, and the thermosetting agent in the sealing agent for a liquid crystal dropping method is derived from the thermosetting agent. The ratio of the amount of active hydrogen in the hardener to the amount of epoxy groups derived from the epoxy-based compound in the sealant for a liquid crystal dropping method is 0.25 or more, the amount of the hardening monomer is 10% by mass or more and 30% by mass or less relative to the total amount of the polymerizable compound, and the amount of the (meth)acrylic-epoxy-containing compound is 30% by mass or more and 70% by mass or less relative to the total amount of the polymerizable compound,

(R ₁ in the general formula (1) represents a

The groups (* represents a bond), _R2 and _R3 each independently represent a group selected from

The group (* represents a bond, m, n and p represent integers of 1 to 30), _R4 and _R5 each independently represent a hydrogen atom or a methyl group), when the sealant for the liquid crystal dropping method is formed into a film with a thickness of 100 μm, irradiated with 3000 mJ/ ^cm2 of light and heated at 120°C for 1 hour to form a film, the initial Young's modulus of the film at 120°C measured by a dynamic viscoelasticity measuring device is 1.0×10 ⁸ Pa or less, and after the film is stored in an environment of 121°C and 100% Rh for 24 hours, the difference between the Young's modulus of the film after the pressure pot test at 120°C measured by the dynamic viscoelasticity measuring device and the initial Young's modulus is 8.0×10 ⁷ Pa or less. The sealant for liquid crystal dripping method as described in claim 5, wherein the molecular weight of the curable monomer is 700 or more. The sealant for liquid crystal dripping method as described in claim 5 further comprises a hardening catalyst, and the melting point of the hardening catalyst is above 100°C. The sealant for liquid crystal dripping method as described in claim 5 further comprises coated particles, wherein the coated particles have a core comprising inorganic particles and a polymer layer covering the core, and the coated particles have a functional group comprising an epoxy group and/or a carbon-carbon double bond on the surface. The sealant for liquid crystal dripping method as described in claim 8, wherein the polymer layer contains a cross-linked polymer. The sealant for liquid crystal dripping method as described in claim 8, wherein the average particle size of the coated particles is 0.2μm~10μm. A method for manufacturing a liquid crystal display panel, comprising: a step of applying a sealant for a liquid crystal dripping method as described in any one of claim 1 to claim 10 on one of a pair of substrates to form a sealing pattern; a step of dripping liquid crystal in the area of the sealing pattern of one of the substrates or on the other substrate when the sealing pattern is not hardened; a step of overlapping the one substrate and the other substrate with the sealing pattern interposed therebetween; and a step of hardening the sealing pattern. A method for manufacturing a liquid crystal display panel as described in claim 11, wherein, in the step of hardening the sealing pattern, the sealing pattern is irradiated with light. A method for manufacturing a liquid crystal display panel as described in claim 12, wherein the light includes visible light. A method for manufacturing a liquid crystal display panel as described in claim 12 or claim 13, wherein, in the step of hardening the sealing pattern, heating is performed after irradiating light. A liquid crystal display panel, comprising: a cured product of a sealant for a liquid crystal dripping method as described in any one of claim 1 to claim 10.