JP6323145B2 - Adhesive and optical member using the same - Google Patents

Description

  The present invention relates to an adhesive that is cured by active energy rays.

  An image display device such as a liquid crystal display (LCD) uses layers having various functions such as anti-glare, viewing angle adjustment, and hard coat on the surface. And when bonding functional layers, such as an antireflection film and a conductive film (ITO film), to a liquid crystal panel, the adhesive using an acrylic polymer was used. However, since a portable information terminal such as a smartphone has a smaller screen than a TV application and requires portability, there has been a strong demand from the market to reduce the thickness of the liquid crystal panel. Instead of a pressure-sensitive adhesive whose adhesive strength decreases when the thickness of the pressure-sensitive adhesive layer is reduced, a thermosetting epoxy adhesive that provides a relatively high adhesive force even when the thickness of the adhesive layer is thin, and an ultraviolet-curable acrylic Adhesives and epoxy adhesives have been studied.

  In addition, the market demanded an adhesive having both an adhesive function and an optical function. Examples of the optical function include refractive index control. A liquid crystal panel generally has a configuration in which a plurality of layers having a plurality of optical functions such as a retardation plate are laminated on a glass substrate and a polarizing plate, but an adhesive used for lamination has a refractive index of about 1.47. Therefore, each member used for lamination (refractive index glass: about 1.52, acrylic resin: about 1.51, polycarbonate: 1.60, polyethylene terephthalate: about 1.65). Since the difference in refractive index between the liquid crystal panel and the liquid crystal panel passes through each layer, the light emission attenuates and the screen becomes dark.

  Therefore, Patent Document 1 discloses an adhesive layer coating material including an ultraviolet curable resin and a thermoplastic resin that can be adjusted in refractive index by inorganic particles.

  Patent Document 2 discloses an adhesive comprising an acrylic polymer containing a cyclic ether group-containing monomer and metal fine particles.

  Patent Document 3 discloses an adhesive containing nanoscale inorganic particles and a dispersant.

JP 2006-182819 A JP 2012-001695 A Special table Hei 11-503773

  However, conventionally, the inorganic fine particles could not be appropriately dispersed in the adhesive, and thus there were problems that the transparency of the adhesive was lowered and that the adhesive force was lowered over time. In addition, since conventional adhesives are insufficient in flexibility, when used for bonding a member such as a flexible display, it is difficult to follow the deformation, and when the bonded film is cut to a desired size, the adhesive is peeled off to the cut end surface. There was a problem that occurred.

  The present invention is an adhesive that has good dispersion of metal oxide particles, the possibility of adjusting the refractive index to a high level, good transparency and flexibility, and adhesive strength that does not easily decrease over time. For the purpose of provision.

The adhesive of the present invention includes four ester units contained in the central skeleton R ⁹ of the dispersant, metal oxide particles having an average primary particle size of 5 to 100 nm, and the (meth) acryloyl group and active energy ray of the dispersant. It is the structure containing at least one of a curable compound.

General formula (2)

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ⁵ and R ⁶ each independently represent an unsubstituted or substituted linear or branched alkylene group or alkyleneoxyalkylene. R ²¹ and R ²² represent a monovalent organic residue having a number average molecular weight of less than 5000, and R ⁹ represents a tetravalent aromatic group or aliphatic group.

According to the present invention having the above structure, the four ester units of the central skeleton R ⁹ of the dispersant form a complex with the metal of the metal oxide fine particles, so that the metal oxide fine particles are highly dispersed in the adhesive. did it. Due to this high degree of dispersion, the adhesive had good adhesive strength and transparency after curing with active energy rays, and had the effect of having moderate flexibility in addition to the effect of being easily adjusted to a high refractive index.

  According to the present invention, it is possible to provide an adhesive in which the dispersion of metal oxide particles is good, the refractive index can be adjusted to a high level, the transparency is good, and the adhesive strength is difficult to decrease after a lapse of time.

  Prior to describing the present invention in detail, terms will be defined. “After time” means a state after long-term use. The (meth) acryloyl group includes an acryloyl group and a methacryloyl group. The (meth) acrylate includes acrylate and methacrylate. Film and sheet are synonymous.

In the adhesive of the present invention, the dispersant represented by the general formula (2) or the general formula (3) is essential, and the four ester units of the central skeleton R ⁹ of the dispersant form a complex with the metal of the metal oxide fine particles. By doing so, the metal oxide fine particles can be highly dispersed in the adhesive. That is, in the dispersant, four ester units possessed by the central skeleton R ⁹ are important, but there are two embodiments depending on the number of substituent (meth) acryloyl groups. Hereinafter, the first embodiment and the second embodiment of the adhesive will be described in order.

<First embodiment>
The adhesive of the present invention contains a dispersant represented by the general formula (2) and metal oxide particles having an average primary particle diameter of 5 to 100 nm. Since the adhesive has an active energy ray-curing property and can form an adhesive layer that can easily control the refractive index, when the adhesive is bonded to a member having the same refractive index, the obtained laminate has a reflection interference fringe. Hard to occur. Therefore, it is preferable to use the adhesive as an adhesive for various optical members such as glass, polarizing plate and retardation plate.

  The 1st embodiment of the adhesive agent of this invention is the structure containing the metal oxide particle whose average primary particle diameter is 5-100 nm and the dispersing agent shown by following General formula (2). The dispersant represented by the general formula (2) has two or more (meth) acryloyl groups.

General formula (2)

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ⁵ and R ⁶ each independently represent an unsubstituted or substituted linear or branched alkylene group or alkyleneoxyalkylene. R ²¹ and R ²² represent a monovalent organic residue having a number average molecular weight of less than 5000, and R ⁹ represents a tetravalent aromatic group or aliphatic group.
In the present invention, “number average molecular weight” and “weight average molecular weight” are numerical values measured using a gel permeation chromatography “HLC-8220GPC” manufactured by Tosoh Corporation, and a separation column: Tosoh Corporation “TSK-GEL SUPER H5000”, “TSK-GEL SUPER H4000”, “TSK-GEL SUPER H3000”, and “TSK-GEL SUPER H2000” manufactured by TSK-GEL SUPER H2000 are connected in series, and tetrahydrofuran with a temperature of 40 ° C. is used for the mobile phase. The value is in terms of polystyrene measured at a flow rate of 0.6 ml / min.

In the dispersant represented by the general formula (2), R ⁹ can be selected from a tetravalent aromatic group or an aliphatic group.
Since the tetravalent aromatic group has a rigid aromatic ring, the cured adhesive layer has excellent cohesive strength and high adhesive strength. Specific examples include a phenyl skeleton, a benzophenone skeleton, a biphenyl skeleton, a phenyl ether skeleton, a diphenyl sulfone skeleton, a diphenyl sulfide skeleton, a perylene skeleton, a fluorene skeleton, a tetrahydronaphthalene skeleton, and a naphthalene skeleton. Among these, a biphenyl skeleton, a naphthalene skeleton, a fluorene skeleton, and a tetrahydronaphthalene skeleton are preferable because they can further improve cohesion and dispersibility.

  The tetravalent aliphatic group has a lower cohesive force than the aromatic group, but can form an adhesive layer having excellent stress relaxation properties. Specifically, a tetravalent aliphatic group having an alkyl skeleton having 4 to 10 carbon chains is preferable. Examples of the aliphatic group include a butane skeleton, a cyclobutane skeleton, a hexane skeleton, a cyclohexane skeleton, and a decalin skeleton. Among these, a cyclobutane skeleton, a cyclohexane skeleton, and a decalin skeleton having an alicyclic structure are preferable because cohesion and stress relaxation can be achieved at a higher level.

R ⁵ and R ^{6 in} the general formula (2) each independently represent an unsubstituted or substituted linear or branched alkylene group or alkyleneoxyalkylene group.
The linear or branched alkylene group is preferably an alkylene group such as a methylene group, an ethylene group, or a polymethylene group having 3 to 10 carbon atoms.
The linear or branched alkyleneoxyalkylene group can be formed, for example, by reacting a polyalkylene oxide with a hydroxyl group-containing (meth) acrylate compound as described later. These alkylene groups or alkyleneoxyalkylene groups are derived from a hydroxyl group-containing (meth) acrylate compound and an epoxy group-containing (meth) acrylate compound as raw materials as described later.
Examples of the substituent of the alkylene group and the alkyleneoxyalkylene group include an alkyl group such as a methyl group and an ethyl group, a hydroxyl group, an acryloyloxymethyl group, an acryloyloxyethyl group, and a phenoxy group.

R ^{21 to} R ²² represent a monovalent organic residue having a number average molecular weight of less than 5000, and specifically, an alkyl group, alkenyl group, or alkynyl group having 1 to 25 carbon atoms which may be substituted with an aryl group. , A (meth) acryloyl group, or a linear or branched alkylene oxide chain or polyester chain bonded to an alkyl group, alkenyl group, alkynyl group or (meth) acryloyl group having 1 to 25 carbon atoms. It is a monovalent organic residue. The number average molecular weight of the monovalent organic residue is preferably 4000 or less, and more preferably 3000 or less.

  In the first embodiment, since the dispersant represented by the general formula (2) has two or more (meth) acryloyl groups on average, it can be cured by active energy rays. And since the said (meth) acryloyl group reacts with an active energy ray, since the said dispersing agent cannot flow easily in an adhesive bond layer, it can suppress the adhesive force fall after time passage.

An example is given and demonstrated about the method of synthesize | combining the dispersing agent shown by General formula (2). The following synthesis method is merely an example, and it goes without saying that the synthesis method is not limited to a single synthesis method.
As a synthesis method, for example, a compound (x1) having an aromatic skeleton or an aliphatic skeleton, and two or more acid anhydride groups, a compound having a number average molecular weight of 5000 or less having a functional group capable of reacting with an acid anhydride group A compound (X) having a carboxyl group is obtained by reacting with the compound (x2). And the compound (X) which has the said carboxyl group can be obtained by making it react with the compound (Y) of the number average molecular weight 5000 or less which has a functional group which can react with a carboxyl group.

  The “functional group capable of reacting with an acid anhydride group” of the compound (x2) is preferably a hydroxyl group, an amino group, an epoxy group, or the like. Among these, a hydroxyl group is more preferable because reaction control is easy.

  The “functional group capable of reacting with a carboxyl group” of the compound (Y) is preferably an epoxy group, an oxazoline group, a hydroxyl group, an amino group, a carbodiimide group, an isocyanate group, an isothiocyanate group, a vinyl ether group or the like.

  Here, when only a compound containing a (meth) acryloyl group is used for the compound (x2) and the compound (Y) in order to improve the active energy ray curability, the dispersant represented by the general formula (2) It becomes a dispersing agent shown by Formula (1). In the present invention, the acid anhydride group is an acid anhydride group derived from a carboxyl group unless otherwise specified.

  Further, the method for synthesizing the dispersant represented by the general formula (2) will be described in detail. For example, the compound represented by the following general formula (4) has a number average molecular weight having a hydroxyl group as a functional group capable of reacting with an acid anhydride group. It is made to react with 5000 or less compounds (x2), and the compound (X) which has a carboxyl group is obtained. An example of the compound (X) having a carboxyl group is the compound represented by the general formula (5). In addition, it is preferable to make the said reaction react at the temperature of 50-120 degreeC in presence of a catalyst as needed.

General formula (4)

(In the formula, R ⁹ represents a tetravalent aromatic group or an aliphatic group.)

General formula (5)

(In the formula, R ⁴¹ and R ⁴² represent a monovalent organic residue having a number average molecular weight of less than 5000, and R ⁹ represents a tetravalent aromatic group or an aliphatic group.)

  Next, the obtained compound (X) having a carboxyl group (for example, a compound represented by the general formula (5)) and a compound (Y) having a functional group capable of reacting with a carboxyl group (for example, the following general formula (6) The compound represented by the general formula (2) can be obtained by reacting the compound represented by In addition, it is preferable to perform the said reaction at the temperature of 50-120 degreeC in presence of a catalyst as needed.

General formula (6)

(In the formula, R ⁰ represents a monovalent organic residue having a number average molecular weight of less than 5000)

The compound represented by the general formula (4) is preferably an aromatic tetracarboxylic dianhydride or an aliphatic tetracarboxylic dianhydride.
Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride having a biphenyl skeleton, oxydiphthalic dianhydride, and diphenyl sulfone tetracarboxylic acid. 9,9-bis (3,4-dicarboxy having a fluorene skeleton, such as dianhydride, diphenyl sulfide tetracarboxylic dianhydride, perylene tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride having a naphthalene skeleton Phenyl) fluorene dianhydride, or 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorene dianhydride, tetrahydronaphthalenecarboxylic dianhydride having a tetrohydronaphthalene skeleton, ethylene glycol bis (Anhydroto Mellitate), and glycerin bis (anhydrotrimellitate) monoacetate, and the like.

  Examples of the aliphatic tetracarboxylic dianhydride include butanetetracarboxylic dianhydride.

  The compound (x2) having a hydroxyl group and a number average molecular weight of 5000 or less is, for example, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol, tert-butanol, 1-pentanol, isopentanol, 1-hexanol. , Cyclohexanol, 4-methyl-2-pentanol, 1-heptanol, 1-octanol, isooctanol, 2-ethylhexanol, 1-nonanol, isononanol, 1-decanol, 1-dodecanol, 1-myristyl alcohol, cetyl alcohol Aliphatic monoalcohols such as 1-stearyl alcohol, isostearyl alcohol, 2-octyldecanol, 2-octyldodecanol, 2-hexyldecanol, behenyl alcohol, oleyl alcohol, Aromatic ring-containing monoalcohols such as zyl alcohol, phenoxyethyl alcohol, paracumylphenoxyethyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol Mono-2-ethylhexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monohexyl ether, propylene glycol mono-2-ethylhexyl ether, diethylene glycol monomethyl ether, diethylene Glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol mono-2-ethylhexyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol Monobutyl ether, dipropylene glycol monohexyl ether, dipropylene glycol mono-2-ethylhexyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, triethylene glycol Monohexyl ether, triethylene glycol mono-2-ethylhexyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, tripropylene glycol monohexyl ether, tripropylene Glycol mono-2-ethylhexyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monopropyl ether, tetraethylene glycol monobutyl ether, tetraethylene glycol monohexyl ether, tetraethylene glycol mono-2-ethylhexyl ether , Tetrapropylene glycol Alkylene glycol such as ethylene glycol monomethyl ether, tetrapropylene glycol monoethyl ether, tetrapropylene glycol monopropyl ether, tetrapropylene glycol monobutyl ether, tetrapropylene glycol monohexyl ether, tetrapropylene glycol mono-2-ethylhexyl ether, tetradiethylene glycol monomethyl ether And monoalkyl ethers.

  The compound (x2) having a hydroxyl group-containing number average molecular weight of 5000 or less is preferably a monoalcohol having an ethylenically unsaturated double bond. The ethylenically unsaturated double bond is, for example, preferably a vinyl group and a (meth) acryloyl group, and more preferably a (meth) acryloyl group. The monoalcohol can be used alone or in combination of two or more.

  Examples of the monoalcohol having an ethylenically unsaturated double bond include compounds containing one, two, and three or more ethylenically unsaturated double bonds. Monoalcohols containing one ethylenically unsaturated double bond are, for example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) Acrylate, 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ethyl 2- (hydroxymethyl) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 1,4-cyclohexanedimethanol mono (meth) Examples include acrylate, 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, and 4-hydroxybutyl vinyl ether. Examples of the monoalcohol containing two ethylenically unsaturated double bonds include 2-hydroxy-3-acryloyloxypropyl methacrylate and glycerin di (meth) acrylate. Examples of the monoalcohol containing 3 ethylenically unsaturated double bonds include pentaerythritol triacrylate. Examples of the monoalcohol containing 5 ethylenically unsaturated double bonds include dipentaerythritol pentaacrylate.

  When the compound (x2) having a hydroxyl group-containing number average molecular weight of 5000 or less uses a monoalcohol containing two or more ethylenically unsaturated double bonds, curability with active energy rays is improved.

  Further, as the compound (x2) having a number average molecular weight of 5000 or less having a hydroxyl group, a compound having a polyalkylene oxide chain or a polylactone chain can be synthesized by ring-opening polymerization of an alkylene oxide or lactone to the aforementioned compound. .

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,4-butylene oxide, 2,3-butylene oxide, 1,3-butylene oxide, and the like. The alkylene oxide can be used alone or in combination of two or more. When the alkylene oxide is used in combination, the bond form may be random or block.

  Examples of the lactone include β-butyrolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, δ-caprolactone, ε-caprolactone, and alkyl-substituted ε-caprolactone. Among these, δ-valerolactone, ε-caprolactone, and alkyl-substituted ε-caprolactone are preferable because of excellent reactivity of ring-opening polymerization. Lactones can be used alone or in combination of two or more. Since the crystallinity when two or more lactones are used in combination is often lowered and becomes liquid at room temperature, it is preferable in terms of workability and compatibility.

  A compound (Y) having a functional group capable of reacting with a carboxyl group and having a number average molecular weight of 5000 or less is, for example, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, dodecyl glycidyl ether, phenyl glycidyl ether, -Tertiary butyl phenyl glycidyl ether, 2,4-dibromophenyl glycidyl ether, 3-methyl-dibromophenyl glycidyl ether (however, the substitution position of bromo is arbitrary), allyl glycidyl ether, ethoxyphenyl glycidyl ether, glycidyl (meta ) Acrylate, 4- (glycidyloxy) butyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate, 3,4-epoxy Rohekishiru (meth) acrylate, methyl glycidyl phthalimide, and styrene oxide and the like.

  The dispersant represented by the general formula (2) is at least one of a compound (x2) having a number average molecular weight of 5000 or less having a hydroxyl group or a compound (Y) having a functional group capable of reacting with a carboxyl group and having a number average molecular weight of 5000 or less. It can be obtained by using a compound having a (meth) acryloyl group.

  As described above, the compound represented by the general formula (2) can be synthesized using no solvent or a solvent. Examples of the solvent include hydrocarbon solvents such as toluene; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; diethyl ether, tetrahydrofuran, and dioxane. Ether solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, and parkrene, etc .; acetonitrile, N, N-dimethylformamide, N, N-dimethylacetamide, and N, N- Examples include polar solvents such as dimethylimidazolidinone. The solvent can be used alone or in combination of two or more.

  In the first embodiment of the adhesive of the present invention, the dispersant represented by the general formula (2) is preferably a dispersant represented by the following general formula (1).

General formula (1)

(Wherein R ^{1 to} R ⁴ each independently represents a hydrogen atom or a methyl group, and R ^{5 to} R ⁸ each independently represents an unsubstituted or substituted linear or branched alkylene group or alkyleneoxyalkylene. R ⁹ represents a tetravalent aromatic group or aliphatic group.)

  Since the dispersant represented by the general formula (1) has at least four (meth) acryloyl groups in the molecule, the active energy ray curability is high.

  As the dispersant represented by the general formula (1), a compound having a (meth) acryloyl group as the compound (x2) having a number average molecular weight of 5000 or less having a hydroxyl group, which has already been explained in the synthesis of the compound represented by the general formula (2), is used. Moreover, it can be obtained by using a compound having a (meth) acryloyl group as the compound (Y) having a functional group capable of reacting with a carboxyl group and having a number average molecular weight of 5000 or less.

  In the present invention, metal oxide particles having an average primary particle diameter of 5 to 100 nm have a function of adjusting the refractive index of the adhesive. When the average primary particle diameter is within the above range, a predetermined refractive index can be obtained, light scattering hardly occurs, and transparency is excellent. In the present invention, the average primary particle diameter is calculated from about 10 to 30 particles that can be observed from a magnified image (1000 to 10,000 times) using a transmission electron microscope (TEM) or a scanning electron microscope (SEM). The average value.

  The metal of the metal oxide particles preferably includes any one of, for example, titanium, zinc, zirconium, antimony, indium, tin, aluminum, and silicon. Specifically, antimony pentoxide, antimony-doped tin oxide (ATO), tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), phosphorus-doped tin oxide (PTO), zinc antimonate (AZO), indium-doped zinc oxide (IZO), tin oxide, ATO-coated titanium oxide, aluminum-doped zinc oxide, titanium oxide, zinc oxide, zirconium oxide, aluminum oxide, and silicon oxide. These can be used alone or in combination of two or more.

  The metal oxide particles preferably have a spherical shape, a rectangular parallelepiped shape, a needle shape, a fiber shape, a spindle shape, and a plate shape. Here, the average primary particle diameter of the metal oxide particles other than the spherical shape is the average primary particle diameter by averaging the shortest sides constituting the particle shape. For example, when the particle has a major axis length and a minor axis length, the minor axis length is averaged.

  The refractive index of the metal oxide particles is, for example, titanium oxide (refractive index 2.5 to 2.7), zinc oxide (refractive index 1.95), zirconium oxide (refractive index 2.4), aluminum oxide (refractive index). 1.6 to 1.7) silicon oxide (refractive index 1.45) and the like.

The metal oxide particles can also form a coating layer on the surface using a silane coupling agent. The presence of the coating layer facilitates dispersibility of the metal oxide particles in the adhesive.
Examples of the silane coupling agent include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxypropyl. A silane compound having two methacryloxy groups such as methyldiethoxysilane, an alkyl group and an alkoxy group;
a silane compound having two acryloxy groups, an alkyl group and an alkoxy group, such as γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, and γ-acryloxypropylmethyldimethoxysilane;
a silane compound having three (meth) acryloxyalkyl groups and three alkoxy groups such as γ-methacryloxymethyltrimethoxysilane and γ-acryloxymethyltrimethoxysilane;
Alkoxysilanes having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane;
Alkoxysilanes having an alkyl group such as 5-hexenyltrimethoxysilane, 9-decenyltrimethoxysilane, styryltrimethoxysilane;
a silane having an aminoalkyl group and an alkoxy group, such as γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane;
γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, β-mercaptomethylphenylethyltrimethoxysilane, mercaptomethyltrimethoxysilane, 6 A compound having a mercapto group such as mercaptohexyltrimethoxysilane, 10-mercaptodecyltrimethoxysilane;
Tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane;
3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane , Phenyltrimethoxysilane, hexamethylsilazane, diphenyldimethoxysilane, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl)- Examples include 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane.

  The metal oxide particles are preferably contained in an amount of 1 to 80% by weight, more preferably 10 to 70% by weight, in a total of 100% by weight of the dispersant represented by the general formula (2) and the metal oxide particles. By including 1 to 80% by weight, the refractive index can be controlled more easily, and the coating of the adhesive layer can be easily formed.

  In the first embodiment of the adhesive of the present invention, an active energy ray-curable compound can be further contained. In the first embodiment, since the dispersant represented by the general formula (2) has two or more (meth) acryloyl groups, it has active energy ray curability, but the curability, the hardness of the adhesive layer, In order to further increase the adhesive strength and the like, it is effective to include an active energy ray-curable compound.

  Examples of the active energy ray-curable compound include compounds having an ethylenically unsaturated double bond group such as a (meth) acryloyl group-containing compound, a fatty acid vinyl compound, an alkyl vinyl ether compound, an α-olefin compound, a vinyl compound, and an ethynyl compound. preferable. These compounds having an ethylenically unsaturated double bond group may further have a functional group such as a hydroxyl group, an alkoxy group, a carboxyl group, an amide group, an epoxy group, or a silanol group.

  The (meth) acryloyl group-containing compound is preferably, for example, an alkyl ester (meth) acrylate, a (meth) acrylate having an alkylene oxide unit, or a (meth) acrylate containing an aromatic ring. The (meth) acryloyl group-containing compound may have a plurality of (meth) acryloyl groups.

  Examples of the alkyl ester (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl ( (Meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) Acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate Rate, eicosyl (meth) acrylate, heneicosyl (meth) acrylate, (meth) acrylates having an alkyl chain of 1 to 22 carbon atoms such as docosyl (meth) acrylate.

  Examples of the (meth) acryloyl group-containing compound containing fluorine include perfluoroalkylalkyl (meth) acrylates having a C 1-20 perfluoroalkyl group. For example, perfluoromethylmethyl (meth) acrylate, perfluoroethylmethyl (meth) acrylate, 2-perfluorobutylethyl (meth) acrylate, 2-perfluorohexylethyl (meth) acrylate, 2-perfluorooctylethyl (meta ) Acrylate, 2-perfluoroisononylethyl (meth) acrylate, 2-perfluorononylethyl (meth) acrylate, 2-perfluorodecylethyl (meth) acrylate, perfluoropropylpropyl (meth) acrylate, perfluorooctylpropyl (Meth) acrylate, perfluorooctyl amyl (meth) acrylate, perfluorooctyl undecyl (meth) acrylate, etc. are mentioned.

  Among the (meth) acrylates having an alkylene oxide unit, (meth) acrylates having a hydroxyl group include, for example, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, and hexaethylene. Glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, tripropylene glycol mono (meth) acrylate, tetrapropylene glycol mono (meth) acrylate, polytetramethylene glycol (meth) acrylate Etc. These compounds have a hydroxyl group at the end of the molecule.

  Among the (meth) acrylates having an alkylene oxide unit, (meth) acrylates having an alkoxy group at the molecular end are, for example, methoxyethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) Acrylate, methoxytetraethylene glycol (meth) acrylate, ethoxytetraethylene glycol (meth) acrylate, propoxytetraethylene glycol (meth) acrylate, n-butoxytetraethylene glycol (meth) acrylate, n-pentoxytetraethylene glycol (meth) Acrylate, tripropylene glycol (meth) acrylate, tetrapropylene glycol (meth) acrylate, methoxyto Propylene glycol (meth) acrylate, methoxytetrapropylene glycol (meth) acrylate, ethoxytetrapropylene glycol (meth) acrylate, propoxytetrapropylene glycol (meth) acrylate, n-butoxytetrapropylene glycol (meth) acrylate, n-pentoxytetra Examples include propylene glycol (meth) acrylate, polytetramethylene glycol (meth) acrylate, methoxypolytetramethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, and ethoxypolyethylene glycol (meth) acrylate.

The (meth) acrylate containing an aromatic ring has a phenyl group, a biphenyl group, a benzyl group, or a phenoxy group. These aromatic rings may be halogenated with bromine, chlorine or the like.
Examples of the (meth) acryloyl group-containing compound having a phenyl group include phenyl (meth) acrylate and orthophenylphenol ethylene oxide-modified acrylate.
Examples of the (meth) acryloyl group-containing compound having a biphenyl group include biphenyl (meth) acrylate and 2.2,2′-diethoxy-biphenyl diacrylate.
Examples of the (meth) acryloyl group-containing compound having a benzyl group include benzyl (meth) acrylate, orthophenylbenzyl acrylate and paraphenylbenzyl acrylate, and pentabromobenzyl acrylate.
Examples of the (meth) acryloyl group-containing compound having a phenoxy group include phenoxydiethylene glycol (meth) acrylate, phenoxyethylene glycol (meth) acrylate, phenoxytriethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, and phenoxy. Examples include hexaethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, and phenoxytetrapropylene ethylene glycol (meth) acrylate. These compounds have a phenoxy group at the end of the molecule.

  Examples of the (meth) acryloyl group-containing compound having a carboxyl group include maleic acid, fumaric acid, itaconic acid, and citraconic acid, and alkyl esters and alkenyl monoesters thereof, and β- (meth) acryloxyethyl phthalate. Examples include monoesters, isophthalic acid β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid.

  Examples of the (meth) acryloyl group-containing compound having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4- Examples thereof include hydroxyvinylbenzene and 2-hydroxy-3-phenoxypropyl (meth) acrylate.

  Examples of the (meth) acryloyl group-containing compound having an epoxy group include glycidyl acrylate and 3,4-epoxycyclohexyl acrylate.

Examples of the (meth) acryloyl group-containing compound having a nitrogen-containing structure include dialkyl (meth) acrylamides such as N, N-dimethylacrylamide and N, N-diethylacrylamide, acryloylmorpholine having a morpholine skeleton, (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N- Monoalkylol (meth) acrylamide such as pentoxymethyl- (meth) acrylamide, N, N-di (methylol) acrylamide N-methylol-N-methoxymethyl (meth) acrylamide, N, N-di (methylol) a Rilamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N, N-di (ethoxymethyl) acrylaminide, N-ethoxymethyl-N-propoxymethylmethacrylamide, N, N-di (propoxymethyl) acrylamide, N-butoxymethyl-N- (propoxymethyl) methacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) methacrylamide, N, N-di (pentoxymethyl) acrylamide A (meth) acryloyl group-containing compound having an amide bond such as dialkyrol (meth) acrylamide such as N-methoxymethyl-N- (pentoxymethyl) methacrylamide;
(Meth) acryloyl group-containing compound having a dialkylamino group such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methylethylaminoethyl (meth) acrylate, dimethylaminostyrene, diethylaminostyrene; and as a counter ion Examples include quaternary ammonium salts of (meth) acryloyl group-containing compounds having a dialkylamino group having halogen ions such as chlorine, bromine and iodine, or QSO ³⁻ (Q: an alkyl group having 1 to 12 carbon atoms).

Examples of the fatty acid vinyl compound include vinyl acetate, vinyl butyrate, vinyl crotonic acid, vinyl caprylate, vinyl laurate, vinyl chloroacetate, vinyl oleate, and vinyl stearate.
Examples of the alkyl vinyl ether compound include butyl vinyl ether and ethyl vinyl ether.

Examples of the α-olefin compound include 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and the like.
Examples of the vinyl compound include allyl compounds such as allyl acetic acid, allyl alcohol, allyl benzene, and allyl cyanide, vinyl cyanide, vinyl cyclohexane, vinyl methyl ketone, styrene, α-methyl styrene, 2-methyl styrene, chlorostyrene, and the like. Can be mentioned. Examples of perfluoroalkyl group-containing vinyl monomers such as perfluoroalkyl and alkylenes include perfluorobutylethylene, perfluorohexylethylene, perfluorooctylethylene, and perfluorodecylethylene. Examples of the alkoxysilyl group-containing vinyl compound include vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, and γ- (meth) acryloxypropyltrimethoxysilane.

  Examples of the ethynyl compound include acetylene, ethynylbenzene, ethynyltoluene, 1-ethynyl-1-cyclohexanol, and the like. These may be used alone or in combination of two or more.

  More preferably, the (meth) acryloyl group-containing compound having a plurality of (meth) acryloyl groups has three or more (meth) acryloyl groups. Thereby, cohesive force and adhesive force can be improved more. Specifically, polyurethane poly (meth) acrylate and polyepoxy poly (meth) acrylate are preferable.

  The polyepoxy poly (meth) acrylate is a compound provided with a (meth) acryloyl group by esterifying an epoxy group of an epoxy resin with (meth) acrylic acid. The epoxy resin is preferably a bisphenol A type epoxy resin, a novolac type epoxy resin, or the like.

  The polyurethane poly (meth) acrylate is, for example, a compound obtained by reacting a diisocyanate with a (meth) acryloyl group-containing compound having a hydroxyl group, an isocyanate group obtained by reacting a polyol and a polyisocyanate under an excess of isocyanate groups. A compound obtained by reacting a urethane-containing prepolymer with a (meth) acryloyl group-containing compound having a hydroxyl group, and a hydroxyl group-containing urethane prepolymer obtained by reacting a polyol and a polyisocyanate under hydroxyl-excess conditions have an isocyanate group. Examples thereof include compounds reacted with (meth) acryloyl group-containing compounds.

  Examples of the polyol include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentane glycol, neopentyl glycol, hexanetriol, trimellilol propane, poly Examples include tetramethylene glycol and a condensation polymer of adipic acid and ethylene glycol.

Examples of the polyisocyanate include tolylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.
As the (meth) acryloyl group-containing compound having a hydroxyl group, the compounds exemplified in the previous step can be used.
Examples of the (meth) acryloyl group-containing compound having an isocyanate group include 2- (meth) acryloyloxyethyl isocyanate and (meth) acryloyl isocyanate.

  In the present invention, when the member to be bonded is a plastic, the active energy ray-curable compound preferably includes a (meth) acryloyl group-containing compound having a hydroxyl group or an alkylene oxide unit. The said compound can improve adhesive force more by having a hydroxyl group or an alkylene oxide unit. The alkylene oxide unit refers to ethylene oxide and propylene oxide.

  When the adhesive of the present invention is used for bonding plastics, it preferably contains an active energy ray-curable compound having one (meth) acryloyl group. By containing the compound, the cohesive force of the adhesive layer is adjusted and the adhesive force is improved. However, the above description does not prevent the (meth) acryloyl group from containing an active energy ray-curable compound having two or more functions.

  The active energy ray-curable compound is preferably included in an amount of more than 0 and not more than 200 parts by weight with respect to a total of 100 parts by weight of the dispersant represented by the general formula (2) and the metal oxide particles, and more preferably 50 to 150 parts by weight. preferable.

  The adhesive of the present invention preferably contains a photopolymerization initiator when a light source other than an electron beam is used as the active energy ray. The photopolymerization initiator is not particularly limited as long as radical polymerization can be initiated by photoexcitation and a known compound can be used. For example, monocarbonyl compounds, dicarbonyl compounds, acetophenone compounds, benzoin ether compounds, acylphosphine oxide compounds, aminocarbonyl compounds, and the like are preferable.

  Specifically, the monocarbonyl compound is, for example, benzophenone, 4-methyl-benzophenone, 2,4,6-trimethylbenzophenone, methyl-o-benzoylbenzoate, 4-phenylbenzophenone, 4- (4-methylphenylthio). Phenyl-ethanone, 3,3′-dimethyl-4-methoxybenzophenone, 4- (1,3-acryloyl-1,3,3′-dimethyl-4-methoxybenzophenone, 4- (1,3-acryloyl-1, 4,7,10,13-pentaoxotridecyl) benzophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 4-benzoyl-N, N, N-trimethyl-1-propane Amine hydrochloride, 4-benzoyl-N, N-dimethyl-N-2- (1-oxo-2-propenyloxy) Ethyl) metaammonium oxalate, 2- / 4-iso-propylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-hydroxy-3- (3 4-dimethyl-9-oxo-9H thioxanthone-2-yloxy-N, N, N-trimethyl-1-propanamine hydrochloride, benzoylmethylene-3-methylnaphtho (1,2-d) thiazoline, and the like.

  Examples of the dicarbonyl compound include 1,2,2-trimethyl-bicyclo [2.1.1] heptane-2,3-dione, benzyl, 2-ethylanthraquinone, 9,10-phenanthrenequinone, and methyl-α-oxo. Examples thereof include benzene acetate and 4-phenylbenzyl. Examples of acetophenone compounds include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-Isopropylphenyl) -2-hydroxy-di-2-methyl-1-phenylpropan-1-one, 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-styrylpropan-1-one Polymer, diethoxyacetophenone, dibutoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,2-diethoxy-1,2-diphenylethane-1-one, 2-methyl-1 -[4- (Methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethyla Mino-1- (4-morpholinophenyl) butan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, 3,6-bis (2-methyl-2-morpholino -Propanonyl) -9-butylcarbazole and the like.

  Examples of the benzoin ether compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzoin normal butyl ether. Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 4-n-propylphenyl-di (2,6-dichlorobenzoyl) phosphine oxide, and the like.

Examples of the aminocarbonyl compound include methyl-4- (dimethoxyamino) benzoate, ethyl-4- (dimethylamino) benzoate, 2-n-butoxyethyl-4- (dimethylamino) benzoate, and isoamyl-4- (dimethylamino). Benzoate, 2- (dimethylamino) ethyl benzoate, 4,4'-bis-4-dimethylaminobenzophenone, 4,4'-bis-4-diethylaminobenzophenone, 2,5'-bis (4-diethylaminobenzal) cyclo Examples include pentanone.
These can be used alone or in combination of two or more.

  In the adhesive of the present invention, a sensitizer (for example, an organic amine) can be used in combination with a photopolymerization initiator. In addition to the radical polymerizable photopolymerization initiator, a photopolymerization initiator for cationic polymerization can be used in combination.

  The photopolymerization initiator is preferably blended in an amount of about 0.05 to 10 parts by weight with respect to a total of 100 parts by weight of the compound having a (meth) acryloyl group.

  The adhesive of the present invention can contain a binder resin. By including a hinder resin, the cohesive strength, adhesive strength, and the like of the adhesive can be adjusted as appropriate. Specifically, for example, polyurethane resin, polyurea resin, polyurethane urea resin, polyester resin, polyether resin, polycarbonate resin, epoxy resin, amino resin, styrene resin, acrylic resin, melamine resin, polyamide resin, phenol resin, vinyl resin Etc. These can be used alone or in combination of two or more. In addition, binder resin is resin which does not harden | cure by active energy ray irradiation, and does not have a (meth) acryloyl group.

  The binder resin preferably contains about 0.1 to 20% by weight in 100% by weight of the nonvolatile content of the adhesive.

The adhesive of the present invention can contain an organic solvent. Specifically, for example, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, acetone, acetylacetone, toluene, xylene, n-butanol, isobutanol, tert-butanol, n-propanol, isopropanol, ethanol, methanol, 3-methoxy-1-butanol , 3-methoxy-2-butanol, ethylene glycol monomethyl ether, ethylene glycol mono n-butyl ether, 2-ethoxyethanol, 1-methoxy-2-propanol, diacetone alcohol, ethyl lactate, butyl lactate, propylene glycol monomethyl ether, ethylene Glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 2-ethoxyethyl acetate, butyl acetate , Isoamyl acetate, dimethyl adipate, dimethyl succinate, dimethyl glutarate, tetrahydrofuran, and methyl pyrrolidone. Among these, since the hydroxyl group-containing solvent has good wettability to the metal oxide particles, the dispersibility is further improved, and the temporal stability of the adhesive can be further improved. Among the hydroxyl group-containing solvents, 3-methoxy-1-butanol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, and ethylene glycol mono n-butyl ether are more preferable.
These can be used alone or in combination of two or more.

  The adhesive of the present invention further contains a surfactant, an antibacterial agent, an antiblocking agent, a plasticizer, an ultraviolet absorber, an infrared absorber, an antioxidant, an inorganic filler, a pigment, a dye, and the like as necessary. be able to.

式中、Ｒ ^３１ 〜Ｒ ^３４ は、数平均分子量５０００未満の１価の有機残基であり、Ｒ ^９ は、４価の芳香族基または脂肪族基を示す。また、一般式（３）で示す分散剤は平均０〜１個の（メタ）アクリロイル基を有する。
<Second embodiment>
The 2nd embodiment of the adhesive agent of this invention is the structure containing the dispersing agent shown by General formula (3), the metal oxide particle whose average primary particle diameter is 5-100 nm, and an active energy ray hardening compound. . The difference between the second embodiment of the adhesive of the present invention and the first embodiment is that the dispersant represented by formula (3) has an average of less than two (meth) acryloyl groups, and An active energy ray-curable compound is an essential component. Since the dispersant represented by the general formula (3) has a central skeleton R9 and four ester units, the dispersibility of the metal oxide particles is equivalent to that of the first embodiment, but the (meth) acryloyl group is 2 on average. Since the active energy ray curability is insufficient because it is less than the number, it is necessary to further contain an active energy ray curable compound. That is, in the second embodiment, it is a mixture of a dispersant represented by the general formula (3) having no (meth) acryloyl group and a dispersant represented by the general formula (3) having two (meth) acryloyl groups. There is a case. In the first embodiment, the dispersant represented by the general formula (3) having no (meth) acryloyl group may be included, but in the first embodiment, only the dispersant represented by the general formula (2) is included. To calculate the number of (meth) acryloyl groups.
General formula (3)

In the formula, R ^{31 to} R ³⁴ are monovalent organic residues having a number average molecular weight of less than 5000, and R ⁹ represents a tetravalent aromatic group or an aliphatic group. Moreover, the dispersing agent shown by General formula (3) has an average of 0-1 (meth) acryloyl group.

  The active energy ray-curable compound is preferably 50 to 200 parts by weight, more preferably 80 to 170 parts by weight with respect to 100 parts by weight in total of the dispersant represented by the general formula (3) and the metal oxide particles.

  The second embodiment of the adhesive of the present invention is the same as the first embodiment except for the points described above.

  The adhesive of the present invention can form an adhesive layer having a high refractive index by controlling the type and amount of metal oxide particles.

  In order to adjust the refractive index of the adhesive layer, the metal oxide particles may be changed. Specific examples include titanium oxide (refractive index 2.5 to 2.7), zirconium oxide (refractive index 2.4), and zinc oxide (refractive index 1.95). In addition, the dispersant represented by the general formula (2) or the general formula (3) (hereinafter sometimes simply referred to as a dispersant) includes an aromatic skeleton in the molecule, thereby improving the refractive index of the adhesive layer. it can.

The adhesive of this invention can disperse | distribute a metal oxide particle favorably in an adhesive agent by fully mixing a dispersing agent and a metal oxide particle.
Examples of the method for producing the adhesive of the present invention include a method of obtaining an adhesive by mechanically mixing a dispersant and metal oxide particles, or a method in which a suspension is prepared by stirring and mixing metal oxide particles and an organic solvent. Examples thereof include a method of preparing an adhesive agent by adding a dispersant while stirring the solution.
For the mechanical mixing, a known apparatus such as a homogenizer, a kneader, a roll, an attritor, a super mill, a ball mill, a bead mill, and a dry pulverizer can be used. In addition, media such as glass beads, zirconia beads, alumina beads, magnetic beads, and styrene beads may be used for the mixing. The dispersing agent and metal oxide particles are dispersed and mixed in the presence of an organic solvent. It is preferable. The degree of dispersion can be measured by “Nanotrack UPA” manufactured by Nikkiso Co., Ltd. using a dynamic light scattering method. In the present invention, as described in Example 1 described later, a metal oxide dispersion paste is prepared, and it is preferably dispersed until the D99 average particle diameter is less than 300 nm by the dynamic light scattering method. It is more preferable to disperse.

  When the adhesive of the present invention contains a raw material other than the dispersant and the metal oxide particles, the raw material is mixed together with the dispersant and the metal oxide particles, or the raw material together with the dispersant and the metal oxide particles. A method of blending and dispersing is preferred.

A method for using the adhesive of the present invention will be described.
The adhesive of the present invention is applied to a substrate to be bonded (also referred to as a member or an adherend), another substrate is bonded, and the adhesive layer is formed by curing by irradiation with active energy rays. . Therefore, any one of the base materials to be used needs to be able to transmit active energy rays. The thickness of the adhesive layer is preferably 0.1 to 30 μm, and more preferably 0.1 to 20 μm. Moreover, it is preferable to adjust a refractive index to 1.4-2, and 1.5-1.8 are more preferable.

Examples of the substrate include metals, ceramics, glass, plastic, wood, slate and the like, and are not particularly limited.
Examples of the shape of the substrate include a sheet, a plate, a lens shape, a disk shape, and a fiber.

Examples of the plastic include polyester, polyolefin, polycarbonate, polystyrene, polymethyl methacrylate, triacetyl cellulose resin, ABS resin, AS resin, polyamide, epoxy resin, and melamine resin.
Moreover, an optical member can be manufactured using the said plastics. Specific examples of the optical member include a polarizing plate, a retardation plate, a protective film, a prism sheet, and a light diffusion film.

  As a method for applying the adhesive, a known method can be used. Specific examples include coating methods such as rods, wire bars, microgravure, gravure, die, curtain, lip, slot, and spin. Further, the solvent can be volatilized by drying with hot air after the application.

  In the present invention, the active energy ray is an electromagnetic wave and particle beam having a curable wavelength. Specifically, ultraviolet rays, electron beams, visible light having a wavelength of 400 to 500 nm, and the like are preferable. Among these, ultraviolet rays and visible light having a wavelength of 400 to 500 nm are preferable. Examples of the active energy ray irradiation source include ultraviolet light and visible light having a wavelength of 400 to 500 nm, such as a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a gallium lamp, a xenon lamp, and a carbon arc lamp. Examples of the electron beam include a thermionic emission gun and an electrolytic emission gun.

Active energy rays used for curing of the adhesive is preferably ^{5~2000mJ / cm 2, 50~1000mJ / cm} 2 is more preferable. In active energy ray irradiation, heat treatment by infrared rays, far infrared rays, hot air, high-frequency heating or the like can be used in combination.

  The adhesive of the present invention can be used for bonding various members, but since a high refractive index is obtained, for example, a cathode ray tube, a flat display panel (liquid crystal display, plasma display, electrochromic display, light emitting diode display, etc.), etc. It is preferably used for manufacturing various display devices.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples shown below, and may be arbitrarily selected without departing from the gist of the present invention and its equivalent scope. You may change to In the following description, “parts” and “%” indicating amounts are based on weight unless otherwise specified.

(Production Example 1: Synthesis of Dispersant 1)
In a four-necked flask equipped with a stirrer, reflux condenser, dry air inlet tube and thermometer, 80.0 parts of biphenyltetracarboxylic dianhydride, pentaerythritol triacrylate (1) (manufactured by Nippon Kayaku Co., Ltd., product Name: KAYARADPET-30) 250.0 parts, hydroquinone 0.16 parts, cyclohexanone 141.2 parts were charged, and the temperature was raised to 85 ° C. Next, 1.65 parts of 1,8-diazabicyclo [5.4.0] -7-undecene was added as a catalyst, and the mixture was stirred at 85 ° C. for 8 hours. Thereafter, 77.3 parts of glycidyl methacrylate and 33.9 parts of cyclohexanone were added, and then 2.65 parts of dimethylbenzylamine was added as a catalyst, stirred at 85 ° C. for 6 hours, and cooled to room temperature to complete the reaction. The obtained Dispersant 1 solution was light yellow and transparent, and had a nonvolatile content of 70%, a number average molecular weight of 920, and a weight average molecular weight of 3,130.

(Production Example 2: Synthesis of Dispersant 2)
In a four-necked flask equipped with a stirrer, a reflux condenser, a dry air introduction tube, and a thermometer, 100.0 parts of 9,9-bis (3,4-dicarboxyphenyl) fluorene dianhydride, pentaerythritol triacrylate ( 2) (Osaka Organic Chemical Co., Ltd., trade name: Biscoat # 300) 200.2 parts, hydroquinone 0.15 parts, cyclohexanone 200.1 parts were charged, and the temperature was raised to 85 ° C. Next, 1.50 parts of 1,8-diazabicyclo [5.4.0] -7-undecene was added as a catalyst, and the mixture was stirred at 85 ° C. for 8 hours. Thereafter, 62.0 parts of glycidyl methacrylate and 42.4 parts of cyclohexanone were added, and then 2.41 parts of dimethylbenzylamine was added as a catalyst, stirred at 85 ° C. for 6 hours, and cooled to room temperature to complete the reaction. The obtained Dispersant 2 solution was light yellow and transparent, and had a nonvolatile content of 60%, a number average molecular weight of 830, and a weight average molecular weight of 2,310.

(Production Example 3: Synthesis of Dispersant 3)
Tetrahydronaphthalene dianhydride 100.0 parts, pentaerythritol triacrylate (1) 305.7 parts, hydroquinone 0.20 parts, cyclohexanone in a four-necked flask equipped with a stirrer, reflux condenser, dry air inlet pipe and thermometer 405.7 parts were charged and heated to 85 ° C. Next, 2.03 parts of 1,8-diazabicyclo [5.4.0] -7-undecene was added as a catalyst, and the mixture was stirred at 85 ° C. for 8 hours. Thereafter, 94.6 parts of glycidyl methacrylate and 96.9 parts of cyclohexanone were added, and then 3.26 parts of dimethylbenzylamine was added as a catalyst, stirred at 85 ° C. for 6 hours, and cooled to room temperature to complete the reaction. The obtained Dispersant 3 solution was light yellow and transparent, and had a nonvolatile content of 50%, a number average molecular weight of 870, and a weight average molecular weight of 3,150.

(Production Example 4: Synthesis of Dispersant 4)
100.0 parts biphenyltetracarboxylic dianhydride, 556.8 parts dipentaerythritol pentaacrylate, 0.33 parts hydroquinone, cyclohexanone in a four-necked flask equipped with a stirrer, reflux condenser, dry air inlet pipe and thermometer 437.8 parts were charged and the temperature was raised to 85 ° C. Next, 3.28 parts of 1,8-diazabicyclo [5.4.0] -7-undecene was added as a catalyst, and the mixture was stirred at 85 ° C. for 8 hours. Thereafter, 96.6 parts of glycidyl methacrylate and 66.8 parts of cyclohexanone were added, and then 5.28 parts of dimethylbenzylamine was added as a catalyst, stirred at 85 ° C. for 6 hours, and cooled to room temperature to complete the reaction. The obtained Dispersant 4 solution was light yellow and transparent, and had a nonvolatile content of 60%, a number average molecular weight of 820, and a weight average molecular weight of 2,660.

(Production Example 5: Synthesis of Dispersant 5)
A 4-necked flask equipped with a stirrer, reflux condenser, dry air inlet tube, thermometer, butanetetracarboxylic dianhydride 100.0 parts, pentaerythritol triacrylate (1) 463.2 parts, hydroquinone 0.28 parts Then, 563.2 parts of cyclohexanone was charged and the temperature was raised to 85 ° C. Next, 2.82 parts of 1,8-diazabicyclo [5.4.0] -7-undecene was added as a catalyst, and the mixture was stirred at 85 ° C. for 8 hours. Thereafter, 143.4 parts of glycidyl methacrylate and 146.5 parts of cyclohexanone were added, and then 4.53 parts of dimethylbenzylamine was added as a catalyst, stirred at 85 ° C. for 6 hours, and cooled to room temperature to complete the reaction. The obtained Dispersant 5 solution was light yellow and transparent, and had a nonvolatile content of 50%, a number average molecular weight of 920, and a weight average molecular weight of 2,200.

(Production Example 6: Synthesis of Dispersant 6)
In a four-necked flask equipped with a stirrer, reflux condenser, dry air inlet tube and thermometer, 50.0 parts butanetetracarboxylic dianhydride, 413.4 parts dipentaerythritol pentaacrylate, 0.23 parts hydroquinone, cyclohexanone 463.4 parts were charged and heated to 85 ° C. Next, 2.32 parts of 1,8-diazabicyclo [5.4.0] -7-undecene was added as a catalyst, and the mixture was stirred at 85 ° C. for 8 hours. Thereafter, 71.7 parts of glycidyl methacrylate and 74.3 parts of cyclohexanone were added, and then 3.73 parts of dimethylbenzylamine was added as a catalyst, stirred at 85 ° C. for 6 hours, and cooled to room temperature to complete the reaction. The obtained Dispersant 6 solution was light yellow and transparent, and had a nonvolatile content of 50%, a number average molecular weight of 900, and a weight average molecular weight of 2,070.

(Production Example 7: Synthesis of Dispersant 11)
In a four-necked flask equipped with a stirrer, reflux condenser, dry air inlet tube, and thermometer, 18.0 parts of isomyristyl alcohol, 38.3 parts of ε-caprolactone, 33.65 parts of δ-valerolactone, monobutyltin as a catalyst 0.02 part of a hydroxide was charged and reacted at 130 ° C. for 3 hours to obtain a polylactone having a number average molecular weight of 1100 having a hydroxyl group at one end. Thereafter, 9.2 parts of pyromellitic anhydride was added and reacted at 120 ° C. for 4 hours. Subsequently, 12.6 parts of phenyl glycidyl ether and 0.80 part of 1,8-diazabicyclo [5.4.0] -7-undecene as a catalyst were added and stirred at 100 ° C. for 8 hours to complete the reaction. The obtained dispersant 11 is a non-solvent light yellow transparent viscous liquid, has a number average molecular weight 2820, a weight average molecular weight 4,170, and does not have an ethylenically unsaturated double bond in the molecule.

(Production Example 8: Synthesis of Dispersant 12)
In a four-necked flask equipped with a stirrer, reflux condenser, dry air inlet tube, and thermometer, 18.0 parts of isomyristyl alcohol, 38.3 parts of ε-caprolactone, 33.65 parts of δ-valerolactone, monobutyltin as a catalyst 0.02 part of a hydroxide was charged and reacted at 130 ° C. for 3 hours to obtain a polylactone having a number average molecular weight of 1100 having a hydroxyl group at one end. Thereafter, 9.2 parts of pyromellitic anhydride was added and reacted at 120 ° C. for 4 hours. Subsequently, 11.9 parts of glycidyl methacrylate and 0.80 part of 1,8-diazabicyclo [5.4.0] -7-undecene as a catalyst were added and stirred at 100 ° C. for 8 hours. The obtained dispersant 12 is a non-solvent light yellow transparent viscous liquid having a number average molecular weight of 2720, a weight average molecular weight of 4,030, and two ethylenically unsaturated double bonds in the molecule. Yes.

(Production Example 9: Synthesis of Dispersant 13)
6.3 parts of diethylene glycol monoacrylate, 44.6 parts of ε-caprolactone, 39.1 parts of δ-valerolactone, monobutyltin as a catalyst in a four-necked flask equipped with a stirrer, reflux condenser, dry air inlet tube and thermometer 0.023 part of hydroxide was charged and reacted at 130 ° C. for 3 hours to obtain a polylactone having a number average molecular weight of 2350 having a hydroxyl group at one end. Thereafter, 4.3 parts of pyromellitic anhydride was added and reacted at 120 ° C. for 4 hours. Next, 5.6 parts of glycidyl methacrylate and 0.75 part of 1,8-diazabicyclo [5.4.0] -7-undecene were added as a catalyst, and the mixture was stirred at 100 ° C. for 8 hours. The obtained dispersant 13 is a light-yellow transparent viscous liquid without solvent, has a number average molecular weight of 5,720, a weight average molecular weight of 7,700, and has four ethylenically unsaturated double bonds in the molecule. doing.

<Example 1>
40 parts of the obtained dispersant 1 solution in terms of non-volatile content, 100 parts of zirconium dioxide, and 187 parts of a methyl isobutyl ketone / 3-methoxy-1-butanol (50/50 wt%) solution as a solvent were placed in a paint shaker, and the media Using zirconia beads, preliminary dispersion was performed to obtain a metal oxide dispersion paste.
100 parts of the obtained metal oxide dispersion paste in terms of non-volatile content and 11.9 parts of a photopolymerization initiator (Irgacure 184 manufactured by BASF Japan Ltd.) were charged into a bead mill disperser (UAM-015 manufactured by Kotobuki Industries Co., Ltd.) Dispersion was performed using zirconia beads as media to obtain an adhesive.

<Examples 2 to 22 and Comparative Examples 1 to 5>
The adhesives of Examples 2 to 22 and Comparative Examples 1 to 5 were obtained by carrying out in the same manner as in Example 1 except that the types and amounts of the raw materials were changed according to the formulations in Tables 1 to 3.

Abbreviations and properties in Tables 1 and 2 are as follows.
ZrO ₂ : Zirconium dioxide “PCS-60” manufactured by Nippon Denko Co., Ltd. (average primary particle size: 20 nm)
TiO _2: Titanium dioxide (average primary particle diameter: 20nm, TTO-51 (A ) manufactured by Ishihara Sangyo Kaisha, Ltd.)
SiO ₂ : Silicon dioxide (average primary particle size: 50 nm, AEROSIL 50 manufactured by Nippon Aerosil Co., Ltd.)
Dispersant 7: Acid group-containing dispersant (Disperbyk-111 manufactured by Big Chemie Japan)
Dispersant 8: Silane coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)
MIBK: methyl isobutyl ketone mettobuta: 3-methoxy-1-butanol monomer 1: 2-hydroxy-3-phenoxypropyl acrylate (Aronix M-5700, (meth) acryloyl group: 1, manufactured by Toagosei Co., Ltd.)
Monomer 2: Orthophenylphenol ethylene oxide modified acrylate (Aronix M-106, (meth) acryloyl group: 1, manufactured by Toagosei Co., Ltd.)
Monomer 3: Ethylene oxide-modified bisphenol A diacrylate (New Frontier BPE-4, (meth) acryloyl group: 2, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
Monomer 4: Tribromophenol acrylate (New Frontier BR-4, (meth) acryloyl group: 1, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
MEK: methyl ethyl ketone The average primary particle size was measured by SEM.

<Creation of evaluation sample>
The obtained adhesive of Example 1 is applied to a PET film having a thickness of 100 μm (easily bonded, Cosmo Shine A-4100, manufactured by Toyobo Co., Ltd.) using a bar coater so that the thickness after drying becomes 3 μm. And dried at 100 ° C. for 1 minute. Thereafter, a peelable film was bonded. Next, using a metal halide lamp, ultraviolet rays were irradiated from the PET film side at 400 mJ / cm ² and cured to form an adhesive layer, thereby obtaining an evaluation sample.
Separately, after applying the adhesive of Example 1 in the same manner as described above, a glass plate was bonded, and an evaluation sample irradiated with ultraviolet rays in the same manner as described above was obtained. In addition, evaluation samples irradiated with ultraviolet rays were obtained in the same manner as described above by replacing the glass plate with a polypropylene plate (PP) or a stainless steel plate (SUS). The adhesive surface of the polypropylene plate is subjected to corona treatment.
The obtained evaluation sample was evaluated by the following method.

[Adhesive strength]
(1) Normal adhesive strength An evaluation sample using a glass plate, an olefin plate and a stainless steel plate was prepared in a size of 25 mm in width and 100 mm in length. Thereafter, a peel test (pulling speed 300 mm / min; unit g / 25 mm width) is performed at a peel angle of 180 ° using a shopper type peel tester in an atmosphere of 23 ° C. and 50% RH. Observed.
○: The PET base material was broken. Good adhesion.
(Triangle | delta): The PET base material and the adhesive bond layer peeled at the interface. Can be used.
X: Cohesive failure of the adhesive layer. I can not use it.
(2) Adhesive strength after time An evaluation sample similar to normal adhesiveness was allowed to stand for 168 hours in an atmosphere of 65 ° C.-80% RH. Thereafter, the sample was left in an atmosphere of 23 ° C. and 50% RH for 12 hours, and a peel test was performed in the same atmosphere at a peel angle of 180 °, and the state of the evaluation sample after peeling was visually observed. The evaluation criteria are the same as above. In Comparative Examples 2 and 4, since the adhesive layer was whitened and the transparency was remarkably impaired, the adhesive strength was not evaluated.

[Haze]
Transparency was evaluated by haze value. First, the peelable film was peeled from the evaluation sample using the peelable sheet, and the haze value was measured using a haze meter NDH-2000 (manufactured by Tokyo Denshoku Co., Ltd.).

[Refractive index]
The peelable film was peeled from the evaluation sample using the peelable sheet, and the refractive index of the adhesive layer was measured using an Abbe refractometer (Atago Co., Ltd.).

[Punching test]
Further, the obtained adhesive of Example 19 was applied to a PET film having a thickness of 100 μm (easily bonded, Cosmo Shine A-4100, manufactured by Toyobo Co., Ltd.) to a thickness of 3 μm after drying using a bar coater. It was applied so that it was dried at 100 ° C. for 1 minute. Thereafter, the same PET film was bonded, and then a UV light was irradiated at 400 mJ / cm ² using a metal halide lamp and cured to obtain a PET film laminate (evaluation sample) having a width of 200 mm × length of 250 mm. The center of this evaluation sample was punched into a square using a blade made by Dumbbell, which can be punched into a square having a width of 100 mm and a length of 100 mm.
When the base material and the adhesive layer are partially peeled off due to the impact of punching, the distance from the punching end (cutting part) to the non-peeling part is measured with a ruler. Rated by stage. The results are shown in Table 5. In this test, the flexibility of the adhesive layer that can withstand the impact or deformation during punching can be evaluated.
A: 0 mm (no peeling, excellent)
○: Less than 1mm (good)
Δ: 1 mm or more and less than 3 mm (practical)
×: 3 mm or more (no practicality)

From the results of Table 4 and Table 5, the examples are adhesives having good adhesive strength and adhesive strength after time, good transparency due to low haze, and having a refractive index that can be controlled to a high level. I understand. For this reason, it can be suitably used as an optical member. In addition, it can be seen from the results in Table 5 that when the number of (meth) acryloyl groups of the dispersant is 0 to 4, an adhesive having excellent punching workability can be obtained.
On the other hand, in Comparative Example 1, since there is no metal oxide particle, a high refractive index cannot be obtained. Since Comparative Example 2 does not use a dispersant, the dispersion of metal oxide particles is poor and transparency cannot be obtained. In Comparative Examples 3 and 5, since the dispersant represented by the general formula (2) or the general formula (3) is not used, the metal oxide particles can be dispersed and the transparency is good. The power was inferior. In Comparative Example 4, another dispersant was used, but the dispersion of the metal oxide particles was poor, and transparency was not obtained.

Claims (6)

An adhesive containing a dispersant represented by the following general formula (2) and metal oxide particles having an average primary particle size of 5 to 100 nm.
General formula (2)

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ⁵ and R ⁶ each independently represent an unsubstituted or substituted linear or branched alkylene group or alkyleneoxyalkylene. R ²¹ and R ²² represent a monovalent organic residue having a number average molecular weight of less than 5000, and R ⁹ represents a tetravalent aromatic group or aliphatic group. The adhesive according to claim 1, wherein the dispersant is a dispersant represented by the following general formula (1).
General formula (1)

(Wherein R ^{1 to} R ⁴ each independently represents a hydrogen atom or a methyl group, and R ^{5 to} R ⁸ each independently represents an unsubstituted or substituted linear or branched alkylene group or alkyleneoxyalkylene. R ⁹ represents a tetravalent aromatic group or aliphatic group.)   Furthermore, the adhesive agent of Claim 1 or 2 containing an active energy ray hardening compound. The adhesive agent containing the dispersing agent shown by following General formula (3), the metal oxide particle whose average primary particle diameter is 5-100 nm, and an active energy ray hardening compound.
General formula (3)

(In the formula, R ^{31 to} R ³⁴ are monovalent organic residues having a number average molecular weight of less than 5000, and R ⁹ represents a tetravalent aromatic group or aliphatic group. Further, the general formula (3) The dispersant represented by has an average of 0 to 1 (meth) acryloyl group.)   The adhesion according to any one of claims 1 to 4, wherein the metal oxide particles contain at least one element selected from the group consisting of titanium, zinc, zirconium, antimony, indium, tin, aluminum, and silicon. Agent.   The optical member provided with the adhesive bond layer formed from the adhesive agent of any one of Claims 1-5, and a base material.