Hardening composition, liquid crystal cell, and method for producing the same

Abstract

To provide: a curable composition which, while maintaining liquid crystal resistance, is curable with light irradiation only and has excellent adhesion to a substrate; a liquid cell comprising the curable composition as a liquid crystal encapsulating material; and a production method of the liquid crystal cell, having excellent productivity of the liquid crystal cell.SOLUTION: A curable composition comprises: polyisobutylene (A) having a carbon-carbon double bond, monomers (B), and a photoinitiator (C), where the monomers (B) comprise a monomer (B1) having an aliphatic ring and a monomer (B2) having a heterocyclic ring.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a curable composition, a liquid crystal cell, and a method for manufacturing the same.

Background Art

[0002] As one of the methods for manufacturing a liquid crystal cell, a liquid crystal droplet discharge method is known. For example, in the liquid crystal droplet discharge method, a sealant is applied on a substrate to form a frame, liquid crystal is dropped into the frame, the opposing substrates are bonded together, and then the sealant is irradiated with light for temporary curing and then heated for full curing to manufacture a liquid crystal cell.

[0003] For example, Patent Document 1 discloses a specific sealant for the liquid crystal droplet discharge method, which contains a curable resin, fillers having different particle sizes, a thermosetting agent, and a radical polymerization initiator, and has excellent adhesiveness and moisture resistance reliability.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In addition to liquid crystal display devices, liquid crystal cells are also beginning to be used as liquid crystal dimming films that switch between transparent and opaque, for example, in in-vehicle applications (such as side glass and sunroofs), building materials (such as window glass and partitions), sunglasses, goggles, etc. The substrate of the liquid crystal dimming film may be not only a glass substrate but also a resin substrate. Although the liquid crystal droplet discharge method is also being studied in the manufacture of liquid crystal dimming films, there has been a problem that conventional sealants require sufficient heating during curing, so a substrate with low heat resistance cannot be selected. Also, from the viewpoint of improving the productivity of liquid crystal cells, simplification of the curing process of the sealant is also required.

[0006] The present invention has been made in view of the above circumstances, and provides a curable composition that can be cured only by light irradiation while maintaining liquid crystal resistance and has excellent adhesion to a substrate, a liquid crystal cell including the curable composition as a liquid crystal sealing material, and a method for manufacturing a liquid crystal cell having excellent productivity of the liquid crystal cell.

Means for Solving the Problems

[0007] [1] A curable composition containing polyisobutylene (A) having a carbon-carbon double bond, a monomer (B), and a photoinitiator (C), wherein the monomer (B) includes a monomer (B1) having an alicyclic ring and a monomer (B2) having a heterocyclic ring. [2] The curable composition according to [1], wherein the monomer (B1) having an alicyclic ring includes a monomer having a glass transition temperature of the homopolymer of 140°C or higher. [3] The curable composition according to [1] or [2], wherein the monomer (B2) having a heterocyclic ring includes a monomer having a glass transition temperature of the homopolymer of 140°C or higher. [4] The curable composition according to any one of [1] to [3], wherein the monomer (B) is 15 to 50 parts by mass with respect to 100 parts by mass of the polyisobutylene (A). [5] The curable composition according to any one of [1] to [4], wherein the monomer (B1) having an alicyclic ring is 65 to 95 parts by mass in 100 parts by mass of the monomer (B). [6] The curable composition according to any one of [1] to [5], wherein the monomer (B2) having a heterocyclic ring is 5 to 35 parts by mass in 100 parts by mass of the monomer (B). [7] The curable composition according to any one of [1] to [6], further containing a plasticizer (D). [8] The curable composition according to any one of [1] to [7], further containing a filler (E). [9] The curable composition according to any one of [1] to [8], which is for liquid crystal sealing.

[10] Two substrates arranged opposite to each other, a sealing member arranged in a frame shape between the two substrates, A liquid crystal filled in a space formed by the two base materials and the sealing member, and A liquid crystal cell, wherein the sealing member is a cured product of any one of the curable compositions [1] to [9].

[11] The liquid crystal cell according to

[10] , wherein the base material is a resin base material.

[12] Applying any one of the curable compositions [1] to [9] on the first base material in a frame pattern, Dropping liquid crystal into the frame of the curable composition, Bonding a second base material to the surface side of the first base material where the frame of the curable composition is formed, A method for manufacturing a liquid crystal cell, comprising irradiating light on the curable composition.

[13] The method for manufacturing a liquid crystal cell according to

[12] , wherein the first base material is a long resin base material and is carried out by a roll-to-sheet method or a roll-to-roll method.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a curable composition that can be cured only by light irradiation while maintaining liquid crystal resistance and has excellent adhesion to a base material, a liquid crystal cell including the curable composition as a liquid crystal sealing material, and a method for manufacturing a liquid crystal cell with excellent productivity.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the curable composition, liquid crystal cell, and manufacturing method thereof according to the present invention will be described. In the present invention, the (meth)acrylic monomer represents at least one of acrylic monomer and methacrylic monomer, and (meth)acrylic oligomer, (meth)acryloyl group, etc. also conform to this. Polyisobutylene (A) having a carbon-carbon double bond may be referred to as "polyisobutylene (A)", monomer (B1) having an alicyclic ring may be referred to as "monomer (B1)", and monomer (B2) having a heterocyclic ring may be referred to as "monomer (B2)". The same applies to other components. In addition, "~" indicating a numerical range includes its lower limit value and upper limit value unless otherwise specified.

[0011] The curable composition according to the present invention contains polyisobutylene (A) having a carbon-carbon double bond, monomer (B), and photoinitiator (C), and is characterized in that the monomer (B) includes monomer (B1) having an alicyclic ring and monomer (B2) having a heterocyclic ring.

[0012] By including monomer (B1) having an alicyclic ring and monomer (B2) having a heterocyclic ring as monomer (B), the compatibility with the above polyisobutylene (A) is significantly improved, and a transparent liquid composition that does not become cloudy can be obtained. In addition, since each of polyisobutylene (A), monomer (B1) having an alicyclic ring, and monomer (B2) having a heterocyclic ring has a bulky structure, contamination by liquid crystal is suppressed even in the uncured state. Further, the ring structures of monomer (B1) having an alicyclic ring and monomer (B2) having a heterocyclic ring improve the adhesion to the resin substrate, resulting in a liquid crystal sealing member having sufficient mechanical strength only by photocuring.

[0013] This curable composition contains at least polyisobutylene (A), monomer (B1) having an alicyclic ring, monomer (B2) having a heterocyclic ring, and photoinitiator (C), and may further contain other components within the scope where the effects of the present invention are achieved. Hereinafter, each component that can be included in this curable composition will be described.

[0014] <Polyisobutylene (A) having a carbon-carbon double bond> Polyisobutylene (A) is a polyisobutylene skeleton ([-CH 2 C(CH 3 ) 2 n -, provided that n is an integer of 2 or more.) Polyisobutylene skeleton is a linear polymer (oligomer) having a large number of methyl groups, the coating film of this composition is suppressed from being contaminated by liquid crystal, and the cured product of this composition is excellent in liquid crystal sealing property. Polyisobutylene (A) has a carbon-carbon double bond. By having the double bond, when irradiated with light, a crosslinking reaction occurs with monomer (B) or between polyisobutylene (A) to form a cured product of this composition. The carbon-carbon double bond is preferably located in the side chain and / or at the end of polyisobutylene (A), and preferably at the end. The carbon-carbon double bond may be a vinyl group, or may be an allyl group or a (meth)acryloyl group. In the present invention, polyisobutylene (A) having a (meth)acryloyl group at the end is particularly preferred. Polyisobutylene (A) may be synthesized, for example, with reference to JP-A-2013-035901, or a commercially available product may be used. Examples of commercially available products include EPION EP400V manufactured by Kaneka Corporation.

[0015] <Monomer (B)> This curable composition uses a combination of a monomer (B1) having an alicyclic ring and a monomer (B2) having a heterocyclic ring as the monomer (B). By combining monomer (B1) and monomer (B2), the compatibility with the polyisobutylene (A) is improved, and a composition excellent in adhesion to the substrate and liquid crystal resistance can be obtained. Also, other monomer (B3) may be included within the range where the effects of the present invention are exhibited.

[0016] ​Monomer (B) may be appropriately selected from compounds having one or more carbon-carbon double bonds in one molecule. As the structure containing a carbon-carbon double bond, in addition to a vinyl group, an allyl group, and a (meth)acryloyl group, a carbon-carbon double bond may be present in an alicyclic ring or a heterocyclic ring described later. From the viewpoints of liquid crystal resistance and curability, etc., a (meth)acryloyl group is preferable. Further, the number of carbon-carbon double bonds in one molecule is preferably 1 to 6 from the viewpoints of curability and adhesion, etc., more preferably 1 to 3 from the viewpoint of suppressing curing shrinkage, and still more preferably 1 to 2. Further, from the viewpoints of curability, adhesion to a substrate, and suppressing curing shrinkage, it is preferable to combine a monofunctional monomer having one carbon-carbon double bond and a bifunctional monomer having two carbon-carbon double bonds. The combination method of the monofunctional monomer and the bifunctional monomer is not particularly limited. For example, a monofunctional monomer (B1) and a bifunctional monomer (B2) may be combined, or a monofunctional monomer (B1), a bifunctional monomer (B1), and a monofunctional monomer (B2) may be combined. Further, from the viewpoint of suppressing the viscosity of the composition, monomer (B) is preferably in a liquid state having a viscosity of 10 mPa·s or less, preferably 8 mPa·s or less at room temperature (25°C).

[0017] (Monomer (B1) having an alicyclic ring) In monomer (B1), the alicyclic ring represents a saturated or unsaturated hydrocarbon ring having no aromaticity, and the hydrogen atoms of the hydrocarbon ring may be substituted. Specific examples of the alicyclic ring include saturated carbon rings such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, and cyclopropene; unsaturated carbon rings such as cyclopentene, cyclohexene, cyclohexadiene, cycloheptene, and cyclooctene; polycyclic condensed rings such as perhydronaphthalene (bicyclo[4.4.0]decane), bicyclo[5.3.0]decane, and tricyclo[8.4.0.0 3,8 tetradecane; polycyclic condensed rings such as norbornane (bicyclo[2.2.2]octane), adamantane (tricyclo[3.3.1.1 3,7 decane), and dimethyloltricyclodecane (tricyclo[5.2.1.0 2,6Examples include crosslinked condensed rings (which also belong to polycyclic condensed rings) such as decane, norbornene (bicyclo[2.2.1]hepta-2-ene), etc. Note that a crosslinked condensed ring refers to a condensed ring containing condensations other than ortho-condensation.

[0018] Examples of the substituent that the alicyclic ring may have include, in addition to groups having a carbon-carbon double bond such as vinyl group, allyl group, (meth)acryloyl group (-C(=O)CR 1 =CH 2 ), oxy(meth)acryloyl group (-O-C(=O)CR 1 =CH 2 ), alkyloxy(meth)acryloyl group (-R 2 -O-C(=O)CR 1 =CH 2 ), alkyl group (-R 3 ), oxyalkyl group (-OR 3 ), oxo group (=O), halogen atom, etc. However, R 1 is a hydrogen atom or a methyl group, R 2 is a linear alkylene group having 1 to 6 carbon atoms, and R 3 is an alkyl group having 1 to 6 carbon atoms which may have a branch. Specific examples of R 2 include methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group. Specific examples of R 3 include methyl group, ethyl group, propyl group, n-butyl group, tert-butyl group, pentyl group, hexyl group, etc. Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom, etc.

[0019] From the viewpoint of liquid crystal resistance, the monomer (B1) preferably has a bulky structure. Specifically, an alicyclic ring having an alkyl group (-R 3 ), oxyalkyl group (-OR 3 ), or oxo group (=O) as a substituent, or a crosslinked condensed ring which may have a substituent is preferable, and a crosslinked condensed ring is more preferable.

[0020] Specific examples of the monomer (B1) include bicyclic (meth)acrylates such as cyclopropyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, etc., tricyclic (meth)acrylates such as dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, adamantyl (meth)acrylate, and the like.

[0021] Also, from the viewpoints of liquid crystal resistance and curability, the glass transition temperature of the homopolymer of the monomer (B1) is preferably 140°C or higher, more preferably 150°C or higher. The glass transition temperature of the homopolymer is the glass transition temperature of the polymer obtained by polymerizing one type of monomer (B1), which may be determined by measurement or referred to the literature value.

[0022] Preferable specific examples of the monomer (B1) include compounds represented by the following (B1-1) to (B1-5). However, R 4 is each independently a group having a carbon-carbon double bond.

[0023]

Chemical formula

[0024] (Monomer (B2) having a heterocyclic ring) In the monomer (B2), the heterocyclic ring represents a ring containing a carbon atom and a heteroatom as atoms constituting the ring skeleton. Examples of the heteroatom include O, N, S, Si, etc. The heterocyclic ring may or may not have aromaticity. The hydrogen atom of the heterocyclic ring may be substituted. Also, the heterocyclic ring may have a carbon-carbon double bond. Specific examples of the heterocyclic ring include aromatic heterocyclic skeletons such as pyrrole, oxazole, imidazole, pyridine, indole, quinoline, benzofuran, and triazine; and non-aromatic heterocyclic skeletons such as tetrahydrofuran, pyrrolidine, tetrahydrothiophene, imidazolidine, oxazolidine, thiazoline, dioxolane, tetrahydropyran, piperidine, thiane, piperazine, morpholine, thiomorpholine, dioxane, dithiane, furan, thiophene, imidazole, oxazole, thiazole, triazole, diazone, oxazine, dioxine, octahydroindole, octahydroisoindole (hexahydrophthalimide), and heptahydrobenzimidazole. From the viewpoint of compatibility with the polyisobutylene (A) and the monomer (B1), it is preferable that the heterocyclic ring does not have aromaticity.

[0025] Examples of the substituent that the heterocyclic ring may have include a vinyl group, an allyl group, a (meth)acryloyl group (-C(=O)CR 1 =CH 2 ), an oxy(meth)acryloyl group (-O-C(=O)CR 1 =CH 2 ), an alkyloxy(meth)acryloyl group (-R 2 -O-C(=O)CR 1 =CH 2 ), etc., groups having a carbon-carbon double bond, and in addition, an alkyl group (-R 3 ), an oxyalkyl group (-OR 3 ), an oxo group (=O), a halogen atom, etc. However, R 1 ~R 3 is the same as the substituent that the alicyclic ring may have.

[0026] Also, from the viewpoints of liquid crystal resistance and curability, the glass transition temperature of the homopolymer of monomer (B2) is preferably 140°C or higher, more preferably 145°C or higher.

[0027] Preferable specific examples of monomer (B2) include compounds represented by the following (B2-1) to (B2-8). However, R 4 is each independently a group having a carbon-carbon double bond.

[0028]

Chemical formula

[0029] (Other monomer (B3)) Monomer (B) may contain other monomer (B3) within the scope where the effects of the present invention are exhibited. Monomer (B3) includes monomers other than monomer (B1) and monomer (B2), such as monomers having no ring structure and monomers having an aromatic carbon ring.

[0030] Specific examples of the monomer (B3) include vinyl monomers such as styrene, vinyltoluene, 2-methylstyrene, t-butylstyrene, chlorostyrene, and vinyl acetate; linear or branched alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isostearyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, and monomers having a hydroxy group including N-hydroxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, and cyclohexanedimethanol mono(meth)acrylate; (meth)acrylates having an aromatic ring such as benzyl (meth)acrylate and phenyl (meth)acrylate; (meth)acrylamides such as methyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, and N-ethoxyethyl (meth)acrylamide; monomers having a carboxy group such as (meth)acrylic acid and carboxyethyl (meth)acrylate; monomers having an amino group such as dimethylaminomethyl (meth)acrylate; and allyl (meth)acrylate. Among them, vinyl monomers, linear or branched alkyl (meth)acrylates, and (meth)acrylates having an aromatic ring are preferable as the monomer (B3).

[0031] Monomer (B1), monomer (B2), and monomer (B3) may all be synthesized and used, or commercially available products may be used. Further, monomer (B1), monomer (B2), and monomer (B3) may each be used alone or in combination of two or more kinds.

[0032] <Mixing ratio of polyisobutylene (A) and monomer (B)> In this curable composition, the ratio of oligomer (A) and monomer (B) may be appropriately adjusted in consideration of the compatibility of each component and the liquid crystal resistance. In this composition, the total ratio of the monomer (B) with respect to 100 parts by mass of polyisobutylene (A) is preferably 15 to 50 parts by mass, more preferably 20 to 45 parts by mass. In 100 parts by mass of the total amount of monomer (B), the monomer (B1) having an alicyclic ring is preferably 65 to 95 parts by mass, more preferably 70 to 90 parts by mass. In 100 parts by mass of the total amount of monomer (B), the monomer (B2) having a heterocyclic ring is preferably 5 to 35 parts by mass, more preferably 10 to 30 parts by mass. Further, in 100 parts by mass of the total amount of monomer (B), monomer (B3) is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 1 part by mass or less.

[0033] <Photoinitiator (C)> The photoinitiator (C) is a component used to promote the photocuring of polyisobutylene (A) and monomer (B), and examples include a photo radical polymerization initiator, a photo cationic polymerization initiator, etc. This curable composition preferably contains a photo radical polymerization initiator from the viewpoint of photocurability and the like, and preferably consists essentially of a photo radical polymerization initiator. The photo radical polymerization initiator is preferably a cleavage type initiator in which the initiator itself cleaves by the action of light to generate radicals. Once the cleavage type initiator generates radicals, it decomposes and loses the function of the initiator, resulting in a decrease in reactivity. Therefore, for example, the risk of unexpected reactions with liquid crystals and the like is suppressed. Further, such a cleavage type initiator is excellent in curability, and after decomposition, the light absorbability decreases, suppressing the coloring of the cured product and improving the transparency.

[0034] (Photo radical polymerization initiator) The photo radical polymerization initiator may be any compound that generates radicals upon irradiation with light and can be appropriately selected and used. Specific examples of the photo radical polymerization initiator include benzophenone, diacetyl, benzyl, benzoin, ω-bromoacetophenone, chloroacetone, acetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, p,p'-bisdiethylaminobenzophenone, Michler's ketone, benzoin methyl ether, benzoin isobutyl ether, benzoin-n-butyl ether, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-one, 2-hydroxy-2-methyl-1-phenyl-propanone multimer, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, methyl benzoylformate, 2,2-diethoxyacetophenone and 4-N,N'-dimethylacetophenones and other carbonyl-based photoinitiators; sulfide-based photoinitiators such as diphenyl disulfide and dibenzyl disulfide; quinone-based photoinitiators such as benzoquinone and anthraquinone; ultraviolet light initiators such as azobisisobutyronitrile and 2,2'-azobispropane; and visible light initiators such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-benzyl-2-(dimethylamino)-4'-morpholinobutylphenone, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholinophenyl)-butan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, etc.

[0035] From the viewpoints of sensitivity, curing rate, etc., carbonyl-based photoinitiators or visible light initiators are preferred as the photo radical polymerization initiator. Among carbonyl-based photoinitiators, 2,2-dimethoxy-2-phenylacetophenone is preferred. As the visible light initiator, 2-benzyl-2-(dimethylamino)-4'-morpholinobutylphenone or 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one is preferred.

[0036] As the photoinitiator (C), commercially available products can be used, and one type can be used alone or two or more types can be used in combination. From the viewpoints of curability and adhesive strength after curing, the photoinitiator (C) is preferably 0.1 to 3 parts by mass, more preferably 0.2 to 2.5 parts by mass, based on 100 parts by mass of the polyisobutylene (A).

[0037] <Optional additive components> This curable composition may further contain other components within the range where the effects of the present invention are exhibited. Examples of such components include fillers, plasticizers, polymerization inhibitors, silane coupling agents, light-shielding materials, thixotropic agents, elastomers, reactive diluents, chain transfer agents, curing accelerators, ion trap agents, ion exchange agents, leveling agents, pigments, dyes, defoaming agents, and the like.

[0038] (Plasticizer (D)) This composition may further contain a plasticizer (D). By containing a plasticizer, the elastic modulus and shrinkage rate can be controlled. In this composition, as the plasticizer (D), a hydrocarbon resin is preferred from the viewpoint of compatibility with the polyisobutylene (A) and the monomer (B). Among hydrocarbon resins, a hydrogenated alicyclic hydrocarbon resin obtained by hydrogenating a polymer of a dicyclopentadiene (DCPD)-based monomer and a hydrogenated alicyclic / aromatic copolymer hydrocarbon resin obtained by hydrogenating a polymer of a DCPD-based monomer and an aromatic (C9)-based monomer are preferred. When using the plasticizer (D), its content ratio is preferably 1 to 20 parts by mass, more preferably 5 to 18 parts by mass, based on 100 parts by mass of the polyisobutylene (A).

[0039] (Filler (E)) From the viewpoints of adjusting viscosity, improving strength after curing, suppressing linear expansibility, etc., the composition may contain filler (E). Filler (E) can be appropriately selected from inorganic fillers and organic fillers and used. Examples of inorganic fillers include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, titanium oxide, alumina, zinc oxide, silicon dioxide, kaolin, talc, glass beads, sericite activated clay, bentonite, aluminum nitride, and silicon nitride. Examples of organic fillers include polymethyl methacrylate, polystyrene, copolymers obtained by copolymerizing monomers constituting these with other monomers, polyester fine particles, polyurethane fine particles, rubber fine particles, and core-shell particles composed of a shell containing a copolymer having a high glass transition temperature and a core of a copolymer having a low glass transition temperature, etc. Filler (E) can be used alone or in combination of two or more. When using filler (E), its content ratio is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass, based on 100 parts by mass of the total amount of the curable composition.

[0040] (Polymerization inhibitor) From the viewpoints of improving storage stability and detergency, the composition may contain a polymerization inhibitor. The polymerization inhibitor can be appropriately selected from those that suppress the curing reaction and used. Examples of polymerization inhibitors include hindered amine-based, hindered phenol-based, quinone-based, phenothiazine-based, and nitrosoamine-based polymerization inhibitors, and among them, hindered phenol-based compounds are preferred. Hindered phenol-based compounds are compounds having a bulky structure at the 2-position and 6-position of phenol, and examples include 2,6-t-butylphenol, 2,6-t-butyl-4-methylphenol, 2,4,6-t-butylphenol, etc. The polymerization inhibitor can be used alone or in combination of two or more. When using a polymerization inhibitor in this curable composition, the content ratio is preferably 0.0001 to 0.5 parts by mass, more preferably 0.0005 to 0.3 parts by mass, based on 100 parts by mass of polyisobutylene (A), from the viewpoint of achieving both storage stability and curability during use.

[0041] (Silane coupling agent) This composition may contain a silane coupling agent from the viewpoint of further improving the adhesiveness to the substrate. Examples of the silane coupling agent include γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-isocyanatopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and the like. These silane coupling agents can be used alone or in combination of two or more. When using a silane coupling agent, the content ratio is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 3 parts by mass, based on 100 parts by mass of polyisobutylene (A).

[0042] (Light-shielding material) This composition may contain a light-shielding material for preventing light leakage and improving contrast near the seal of the liquid crystal element. Here, the light-shielding property means that the cured product of this composition containing the light-shielding material has an OD (optical density) value of 2 to 5. It is preferable to use a light-shielding material with low contamination to the liquid crystal. Examples include carbon black, titanium black, and the like. The light-shielding material can be used in an amount of 50 parts by mass or less, preferably 5 to 40 parts by mass, more preferably 10 to 30 parts by mass, based on 100 parts by mass of polyisobutylene (A).

[0043] (Thixotropy-imparting agent) For the purpose of improving coatability, etc., the composition may contain a thixotropic agent. Examples of the thixotropic agent include particulate silica such as fumed silica, particulate alumina, and non-spherical particles such as aliphatic amides. From the viewpoint of suppressing the unevenness of the sealant interface after lamination, the amount of the thixotropic agent is preferably 10 parts by mass or less with respect to 100 parts by mass of polyisobutylene (A). From the viewpoint of improving coatability, 0.1 to 5 parts by mass is preferable, and 0.5 to 3 parts by mass is more preferable.

[0044] <Uses of the curable composition> Since the curable composition can be cured only by light irradiation and has excellent liquid crystal resistance, it can be suitably used as a sealant for liquid crystal encapsulation that comes into contact with liquid crystal. In particular, it can be suitably used as a sealant for the liquid crystal droplet method that comes into contact with liquid crystal in an uncured state. Further, since it can be cured only by light irradiation, it can be suitably used even for a resin substrate having relatively low heat resistance as a substrate, and for example, a flexible liquid crystal cell can also be suitably manufactured.

[0045] [Liquid crystal cell] The liquid crystal cell according to the present invention is characterized by including a cured product of the above curable composition. In this liquid crystal cell, the cured product has excellent liquid crystal resistance, and the disturbance of the liquid crystal, etc. is suppressed.

[0046] An example of the liquid crystal cell will be described with reference to FIG. 1. FIG. 1 is a plan view showing an example of the liquid crystal cell 100. As shown in FIG. 1, the liquid crystal cell 100 includes two substrates (a first substrate 10 and a second substrate 40) arranged opposite to each other, a sealing member 21 arranged in a frame shape between the two substrates, and a liquid crystal 30 filled in a space formed by the two substrates and the sealing member 21. In this liquid crystal cell, since the sealing member 21 is a cured product of the curable composition, it has excellent liquid crystal resistance.

[0047] The first substrate 10 and the second substrate 40 are usually substrates that are transparent to visible light. As the substrate, in addition to glass substrates such as quartz glass, non-alkali glass, and synthetic quartz plates, a resin substrate may also be used. Since the present curable composition does not require a thermal effect, a liquid crystal cell can be manufactured while suppressing damage to the resin substrate. Examples of the material of the resin substrate include acetyl cellulose-based resins such as triacetyl cellulose, polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, olefin-based resins such as polyethylene and polymethylpentene, acrylic resins, polyurethane-based resins, transparent resins such as polyethersulfone, polycarbonate, polysulfone, polyether, polyether ketone, acrylonitrile, methacrylonitrile, and cycloolefin copolymer (COP). The thickness of the substrate is not particularly limited, but for example, those having a thickness of about 50 μm or more and 1 mm or less can be used. On the surface of the substrate in contact with the liquid crystal, depending on the driving method of the liquid crystal cell, an alignment film for aligning the liquid crystal may be provided. When having an alignment film, the alignment film may be any of a rubbed alignment film, an optical alignment film, and a shaped alignment film. The substrate may further appropriately have a known configuration that can be used in a liquid crystal cell, such as a transparent electrode layer or a color filter. Also, the liquid crystal 30 is not particularly limited and may be appropriately selected from known liquid crystals used in liquid crystal cells according to the driving method of the liquid crystal or the like.

[0048] <Method for manufacturing a liquid crystal cell> The method for manufacturing a liquid crystal cell will be described with reference to FIG. 2. FIG. 2 is a schematic process diagram showing an example of the method for manufacturing a liquid crystal cell 100, and FIGS. 2(a) to 2(d) are cross-sectional views of the liquid crystal cell 100 in each of the processes (a) to (d) described later. FIG. 2(e) corresponds to the cross-sectional view taken along the cutting line IIE-IIE in FIG. 1. As shown in the example of Fig. 2, the method includes: a step (a) of applying the curable composition 20 onto the first substrate 10 in a frame pattern; a step (b) of dropping a liquid crystal 30 into the frame; a step (c) of bonding a second substrate 40 to the surface side of the first substrate 10 where the frame of the curable composition 20 is formed; and a step (d) of irradiating the curable composition 20 with light.

[0049] The method of applying the curable composition 20 in step (a) is not particularly limited and may be appropriately selected from known printing methods and coating methods. In the example of Fig. 1, the curable composition 20 is applied to the edge of the first substrate 10, but depending on the application, etc., it may be formed inside the first substrate 10, or after forming a plurality of frame patterns, the first substrate may be cut.

[0050] The method of dropping the liquid crystal 30 in step (b) is not particularly limited and may be appropriately selected from known methods. Although the uncured curable composition 20 comes into contact with the liquid crystal 30, when using this curable composition, the elution of the curable composition into the liquid crystal, etc. is suppressed, and the disturbance of the liquid crystal alignment is suppressed.

[0051] Next, in step (c), the first substrate 10 and the second substrate 40 are bonded together through the curable composition to enclose the liquid crystal 30. Thereafter, in step (d), light irradiation is performed to cure the uncured curable composition 20 and obtain a sealing member 21. The curing conditions in step (d) may be appropriately adjusted according to the composition of the curable composition. For example, by irradiating with ultraviolet light at 1,000 mJ / cm 2 and then heating at about 100 - 120 °C for about 1 hour, a sealing member 21 which is a cured product of the curable composition 20 is formed. Since the curable composition is used, a sealing member sufficiently cured by light irradiation can be obtained. On the other hand, for the purpose of stress relaxation by heat, aging (re - alignment treatment) of the liquid crystal, etc., heat treatment may be performed as necessary. In the liquid crystal cell of the present invention, since the sealing member 21 is a cured product of the curable composition of the present invention, the disturbance of the liquid crystal alignment is suppressed.

[0052] In this manufacturing method, since a thermosetting process is not required, a transparent resin substrate on a film can be suitably used as the first substrate 10 and the second substrate 40. In this case, by using a long resin substrate as at least the first substrate, each of the above steps can be carried out as a series of steps by a roll-to-sheet method or a roll-to-roll method. FIG. 3 is a schematic diagram showing an example of a manufacturing method of a liquid crystal cell by a roll-to-sheet method or a roll-to-roll method. As shown in the example of FIG. 3, a long first substrate 10 is conveyed by a roller, and a curable composition 20 is applied in a predetermined frame pattern using a printing roll 51. Next, liquid crystal 30 is dropped into the frame using dropping means 52, a long second substrate is overlaid, and the curable composition 20 is cured by irradiating light using light irradiation means 53 to form a sealing member 21, thereby manufacturing a liquid crystal cell. The long liquid crystal cell may be once wound into a roll and conveyed (not shown), and may be cut at another location (roll-to-roll method), or a single-sheet liquid crystal cell may be manufactured by a cutting means (not shown) as a post-process after light irradiation (roll-to-sheet method).

Examples

[0053] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

[0054] [Raw materials] <Polyisobutylene (A)> (A-1): Manufactured by Kaneka Corporation, EPION EP400V (polyisobutylene having acryloyl groups at both ends) <Other oligomer (A’)> (A’-2): Urethane acrylate-modified polybutadiene

[0055] <Monomer (B1)> (B1-1): Isobornyl methacrylate (monofunctional, glass transition temperature (Tg) of the homopolymer is 180 ° C) (B1-2): Dimethylol-tricyclodecane diacrylate (bifunctional, Tg of the homopolymer is 187 ° C) (B1-3): 3,3,5-Trimethylcyclohexyl acrylate (monofunctional, Tg of homopolymer is 52 °C)

[0056] <Monomer (B2)> (B2-1): Morpholine acrylamide (monofunctional, Tg of homopolymer is 145 °C)

[0057] <Photoinitiator (C)> (C-1): 2-Benzyl-2-(dimethylamino)-4'-morpholinobutyl phenone (Omnirad 369E) (C-2): 2,2-Dimethoxy-2-phenylacetophenone (Omnirad 651) (C-3): 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (Omnirad 907)

[0058] <Plasticizer (D)> (D-1): Hydrogenated hydrocarbon resin (DCPD) (manufactured by ENEOS Corporation, HA-105) (D-2): Hydrogenated hydrocarbon resin (DCPD / C9) (manufactured by ENEOS, HB-125)

[0059] <Filler (E)> (E-1): Acrylic particles (average particle diameter 2 μm; manufactured by Nippon Shokubai Co., Ltd., MV1002) (E-2): Acrylic particles (average particle diameter 2.2 μm; manufactured by Negami Kogyo Co., Ltd., J-4PY)

[0060] [Example 1: Production of curable composition] 3.5 parts by mass of polyisobutylene (A-1), 0.95 parts by mass of monomer (B1-1), 0.1 parts by mass of monomer (B1-2), 0.25 parts by mass of monomer (B2-1), 0.02 parts by mass of photoinitiator (C-1), and 0.5 parts by mass of plasticizer (D-1) were blended and kneaded well while heating to 60 °C to obtain a composition. The compatibility of the said composition was evaluated as described later. Next, 1.6 parts by mass of filler (E-1) was blended into the said composition and kneaded and dispersed well to obtain a curable composition.

[0061] [Examples 2 to 14, Comparative Examples 1 to 7: Production of Curable Compositions] In Example 1, except that each component and the compounding amount were changed as shown in Table 1, each curable composition was obtained in the same manner as in Example 1.

[0062] [Evaluation] [Compatibility Evaluation] Regarding the composition containing the polyisobutylene (A), the monomer (B), and the photoinitiator (C), the compatibility was evaluated based on the transparency of the composition. The results are shown in Table 1. (Evaluation Criteria) 〇 (Excellent): No cloudiness was confirmed (it was a transparent liquid). △ (Fair): Some cloudiness was confirmed. × (Poor): Cloudiness was confirmed.

[0063] [Adhesion Strength Evaluation] The adhesion strength was evaluated by the following 180-degree peel strength test. Specifically, first, the curable composition was applied to the PI side surface of a polyimide (PI) / ITO / polyethylene terephthalate (PET) laminated substrate, and it was laminated so that the thickness of the curable composition became 20 μm to form PET / ITO / PI / curable composition / PI / ITO / PET. For PI, SE-5291 manufactured by Nissan Chemical Industries, Ltd. was used, and for the ITO / PET substrate, an ITO-PET film manufactured by Gunze Ltd. was used. Next, using a metal halide lamp (with a bandpass filter of 340 nm to 440 nm) from above the substrate, UV irradiation was performed at an irradiation dose of 3,000 mJ / cm 2 (100 mW × 30 s) to cure the composition. The obtained laminate was cut into test pieces with a size of 5 cm × 10 mm wide. As shown in Figure 4, a part of the test piece 60 was peeled off, each substrate of the peeled part of the test piece was set in a chuck (fixture) 61, the distance between the upper and lower chucks was set to 3 cm, and the peel strength was measured under the condition of a tensile speed of 10 mm / min. The results are shown in Table 1.

[0064] [Orientation Evaluation] The method for evaluating the orientation will be described with reference to Fig. 6. (a) in Fig. 6 is a top view, and (b) is a side view. The surface on the PI side of the PI / glass laminated substrate 71 was rubbed to form an alignment film for the TN mode. A 12-μm spacer was sprayed on the alignment film surface. The curable composition 72 was applied to five locations, i.e., the central part (for testing) and four corners (for fixing) as shown in Fig. 5, on the alignment film surface. TN liquid crystal 73 (MLC-11900 manufactured by Merck) was dropped onto the central curable composition 72, and then the surface on the PI side of another PI / glass laminated substrate 74 was bonded onto the liquid crystal from above, fixed, and UV irradiation was performed at an irradiation dose of 3,000 mJ / cm 2 2 was irradiated, and after aging at 100°C for 1 hour, the cell was sandwiched between polarizing plates with the cross Nicol arrangement, and the alignment defects around the central sealant were observed by transmission. Note that SE-7492 manufactured by Nissan Chemical Industries, Ltd. was used as the PI. The results are shown in Table 1. Note that "-" in Table 1 indicates that the measurement was not performed. (Evaluation Criteria) 〇 (Excellent): No alignment defects were observed. △ (Good): The alignment defects were less than 0.5 mm. × (Poor): The alignment defects were 0.5 mm or more.

[0065]

Table 1

[0066] As shown in Table 1, it was revealed that the curable compositions of Examples 1 to 14, which are combinations of polyisobutylene (A) having a carbon-carbon double bond, a monomer (B1) having an alicyclic ring, a monomer (B2) having a heterocyclic ring, and an initiator (C), are excellent in compatibility, liquid crystal resistance, and adhesion to the substrate. Thus, according to the present invention, a curable composition capable of forming a sealing member excellent in liquid crystal resistance and adhesion without performing thermosetting can be obtained.

Explanation of Reference Numerals

[0067] 10: First substrate, 20: Curable composition, 21: Sealing member 30: Liquid crystal, 40: Second substrate, 51: Printing roll, 52: Dropping means, 53: Light irradiation means, 60: Test piece, 61: Chuck, 71: Glass laminated substrate, 72: Curable composition, 73: Liquid crystal, 74: Glass laminated substrate, 100: Liquid crystal cell

Claims

1. A curable composition containing polyisobutylene (A) having a carbon-carbon double bond, a monomer (B), and a photoinitiator (C), wherein the monomer (B) includes a monomer (B1) having an alicyclic ring and a monomer (B2) having a heterocyclic ring, and being for liquid crystal sealing.

2. A curable composition containing polyisobutylene (A) having a carbon-carbon double bond, a monomer (B), and a photoinitiator (C), wherein the monomer (B) includes a monomer (B1) having an alicyclic ring and a monomer (B2) having a heterocyclic ring, and the monomer (B2) having a heterocyclic ring includes a monomer having a glass transition temperature of the homopolymer of 140°C or higher.

3. The curable composition according to claim 1 or 2, wherein the monomer (B1) having an alicyclic ring includes a monomer having a glass transition temperature of the homopolymer of 140°C or higher.

4. The curable composition according to claim 1, wherein the monomer (B2) having a heterocyclic ring includes a monomer having a glass transition temperature of the homopolymer of 140°C or higher.

5. The curable composition according to claim 1 or 2, wherein the monomer (B) is 15 to 50 parts by mass with respect to 100 parts by mass of the polyisobutylene (A).

6. The curable composition according to claim 1 or 2, wherein the monomer (B1) having an alicyclic ring is 65 to 95 parts by mass in 100 parts by mass of the monomer (B).

7. The curable composition according to claim 1 or 2, wherein the monomer (B2) having a heterocyclic ring is 5 to 35 parts by mass in 100 parts by mass of the monomer (B).

8. The curable composition according to claim 1 or 2, further containing a plasticizer (D).

9. The curable composition according to claim 1 or 2, further containing a filler (E).

10. Two substrates arranged opposite to each other, A sealing member arranged in a frame shape between the two substrates, And a liquid crystal filled in the space formed by the two substrates and the sealing member, and The liquid crystal cell, wherein the sealing member is a cured product of the curable composition according to claim 1 or 2.

11. The liquid crystal cell according to claim 10, wherein the substrate is a resin substrate.

12. Coating the curable composition according to claim 1 or 2 on the first substrate in a frame pattern, Dropping liquid crystal into the frame of the curable composition, Bonding a second substrate to the surface side of the first substrate where the frame of the curable composition is formed, And irradiating the curable composition with light. A method for manufacturing a liquid crystal cell.

13. The manufacturing method of the liquid crystal cell according to claim 12, wherein the first substrate is a long resin substrate and is carried out by a roll-to-sheet method or a roll-to-roll method.

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