JP2003238904A - Photocuring adhesive composition for optical use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocuring adhesive composition for optical use that is favorably used particularly as a photocuring adhesive used for bonding optical articles such as lenses and prisms, and has a high refractive index, good curability, and strong adhesive strength by including a specific mercapto compound, a photo-polymerization initiator, and a silane coupling agent in the adhesive. <P>SOLUTION: The adhesive is mainly constituted of a photocuring adhesive composition containing a mercapto compound having at least ≥2 thiol end groups, a compound having ≥2 unsaturated bonds, a photo-polymerization initiator, and a silane coupling agent. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photocurable optical adhesive composition, and more particularly to a high refractive index photocurable optical adhesive composition. Further, the present invention relates to an adhesive suitable for increasing light utilization efficiency by eliminating loss of transmitted light due to reflection at an interface when adhering a translucent material such as an optical material or an electronic material. .

[0002]

2. Description of the Related Art For the assembly of optical transmission components and optical components, methods such as soldering and laser welding have been adopted from the viewpoint of reliability. However, since it cannot be used in a portion where light passes or where high temperature is disliked, and a high-level joining technique is required, a method using an adhesive has been changed as a simple method. In particular, adhesion of a portion through which light passes, such as bonding optical components such as lenses and prisms, is required to have the same refractive index as that of the optical member of the base material and performance such as transparency.

That is, when transmitting light to a light-transmitting member such as a lens or a prism used as an optical material or an optoelectronic material, reflection loss on the surface becomes a problem, and a plurality of substances having different refractive indexes are used. When light is transmitted, reflection loss occurs corresponding to the number of interfaces, and it becomes impossible to secure sufficient transmittance. Since the reflectivity of the substance is determined by the difference in the refractive index of the materials that make up the interface, in order to reduce this loss, it is necessary to use a material having a similar index of refraction as the base material at the interface. Therefore, the refractive index equivalent to that of the member is particularly required for bonding various optical members.

Further, as an adhesive agent for adhering these optical members, there are actually thermoplastic natural resins such as Canada balsam, epoxy resin type adhesive agent, acrylic resin type adhesive agent and the like. However, the refractive index of Canadian balsam is 1.
In addition, the conventional epoxy resin adhesives and acrylic resin adhesives have a refractive index of about 1.51 to 1.58, and these adhesives have a high refractive index of 1.60 or more. When used as an adhesive for members, it has a drawback that the light transmittance is lowered. Further, as a refractive index of 1.59 or more, an epoxy adhesive containing bromine is also known, but its refractive index is limited to 1.61.

In order to improve these drawbacks, JP-A-7-
Japanese Patent No. 3237 discloses an adhesive containing a compound having a thiol (meth) acrylate group and a compound having an epoxy group.

[0006]

However, in the above-mentioned prior art, the compound having a thiol (meth) acrylate group alone has a high refractive index but a large curing shrinkage rate, and there is a problem in distortion and adhesiveness. On the other hand, when the content of the compound having an epoxy group is increased to enhance the adhesiveness, there is a problem that the refractive index is lowered, and it is difficult to obtain an adhesive that satisfies both the high refractive index and the high adhesiveness.

Therefore, the present invention has been made to solve the above-mentioned problems, and it is cured with a high refractive index by an adhesive containing a specific mercapto compound, a photopolymerization initiator and a silane coupling agent. Good adhesion, high adhesive strength,
In particular, it is an object of the present invention to provide a photocurable optical adhesive composition that is preferably used as a photocurable adhesive.

[0008]

In order to solve the above-mentioned problems, in the invention of claim 1, the photocurable optical adhesive composition has a mercapto compound having at least two thiol terminal groups. And a compound having two or more unsaturated double bonds, a photopolymerization initiator, and a silane coupling agent are the most main features.

In the invention according to claim 2, the main feature of the photocurable optical adhesive composition is that the mercapto compound having two or more thiol terminal groups has at least the structure of the general formula (1). And N in formula (1)
Represents a positive integer.

In a third aspect of the invention, the photocurable optical adhesive composition is mainly characterized in that the mercapto compound having two or more thiol terminal groups contains at least a phenyl sulfide structure.

In the invention of claim 4, the photocurable optical adhesive composition is a compound having two or more unsaturated double bonds to be copolymerized with a mercapto compound having two or more thiol terminal groups. Has at least the structure of the general formula (1).

In a fifth aspect of the present invention, the photocurable optical adhesive composition is at least a compound having two or more unsaturated double bonds to be copolymerized with a mercapto compound having two or more thiol terminal groups. The main feature is that it contains a phenyl sulfide structure.

In the invention of claim 6, the main feature of the photocurable optical adhesive composition is that the photopolymerization initiator is at least a liquid or a photoradical polymerization initiator compatible with the liquid initiator. And

According to a seventh aspect of the invention, in the photocurable optical adhesive composition, the photoradical polymerization initiator compatible with the liquid or liquid initiator contains at least a phosphorus photopolymerization initiator. That is the main feature.

In the invention of claim 8, the photocurable optical adhesive composition uses a compound in which a compound having two or more unsaturated double bonds is liquid at room temperature or compatible with the liquid compound. Is the main feature.

According to a ninth aspect of the present invention, the photocurable optical adhesive composition uses a compound in which a mercapto compound having two or more thiol terminal groups is liquid at room temperature or compatible with the liquid compound. The main feature.

In a tenth aspect of the invention, the photocurable optical adhesive composition is characterized mainly in that the silane coupling agent contains at least a sulfur atom in the molecular structure.

In the invention according to claim 11, in the photocurable optical adhesive composition, the reaction equivalent ratio of the thiol terminal group to the unsaturated double bond in the photocurable optical adhesive composition is 1:
The main characteristic is 1 to 1: 5.

In the invention of claim 12, the photocurable optical adhesive composition mainly comprises a photopolymerization initiator having a light absorption of 405 nm or more and a photopolymerization initiator having a light absorption of 365 nm or less. It is a characteristic.

In the thirteenth aspect of the invention, the photocurable optical adhesive composition is mainly characterized in that a photopolymerization initiator and a thermal polymerization initiator are used in combination.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. Examples of the mercapto compound having two or more thiol terminal groups used in the present invention include 4,4 ′
-Bis (mercaptomethyl) phenyl sulfide, 2,
4'-bis (mercaptomethyl) phenyl sulfide,
2,4,4'-tri (mercaptomethyl) phenyl sulfide, 2,2 ', 4,4'-tetra (mercaptomethyl) phenyl sulfide, 4,4'-bis (4-mercapto-2-thiabutyl) phenyl sulfide , 2, 4 '
-Bis (4-mercapto-2-thiabutyl) phenyl sulfide, 2,4,4'-tri (4-mercapto-2-
Thiabutyl) phenyl sulfide, 2,2 ', 4,4'
-Tetra (4-mercapto-2-thiabutyl) phenyl sulfide, 4,4'-bis (7-mercapto-2,5
-Dithiaheptyl) phenyl sulfide, 2,4'-bis (7-mercapto-2,5-dithiaheptyl) phenyl sulfide, 2,4,4'-tri (7-mercapto-
2,5-dithiaheptyl) phenyl sulfide, 2,
2 ', 4,4'-Tetra (7-mercapto-2,5-dithiaheptyl) phenyl sulfide, 4-mercaptomethyl-4'-(4-mercapto-2-thiabutyl) phenyl sulfide, 2-mercaptomethyl-4 ' -(4-
Mercapto-2-thiabutyl) phenyl sulfide, 4
-Mercaptomethyl-2 '-(4-mercapto-2-thiabutyl) phenyl sulfide, 4- (4-mercapto-2-thiabutyl) -4'-(7-mercapto-2,5
-Dithiaheptyl) phenyl sulfide, 2- (4-mercapto-2-thiabutyl) -4 '-(7-mercapto-2,5-dithiaheptyl) phenyl sulfide, 4-
(4-Mercapto-2-thiabutyl) -2 '-(7-mercapto-2,5-dithiaheptyl) phenyl sulfide, 4-mercaptomethyl-4'-(7-mercapto-
2,5-Dithiaheptyl) phenyl sulfide, 2-mercaptomethyl-4 ′-(7-mercapto-2,5-dithiaheptyl) phenyl sulfide, 4-mercaptomethyl-2 ′-(7-mercapto-2,5-dithiaheptyl) Examples thereof include phenyl sulfide.

Examples of the mercapto compound having the structure of the general formula (1) include bis (2-mercaptoethyl) sulfide, bis (3-mercaptopropyl) sulfide, bis (4-mercaptobutyl) sulfide, bis (8-mercaptooctyl). ) Sulfide, etc., 1,2-benzenedithiol, 1,4-benzenedithiol, 4-methyl-
1,2-Benzenedithiol, 4-butyl-1,2-benzenedithiol, 4-chloro-1,2-benzenedithiol and the like can also be mentioned. In addition, tetrakis- (7
-Mercapto-2,5-dithiaheptyl) methane and the like can also be mentioned.

Further, as the mercapto compound, 2,
4,6-trimercapto-1,3,5-triazine,
2,4-dimercapto-6- (2-mercaptoethylthio) -1,3,5-triazine, 2,6-dimercapto-4- (2-mercaptoethylthio) -1,3,5-triazine, 4, 6-dimercapto-2- (2-mercaptoethylthio) -1,3,5-triazine, 2,4,6
-Tri (2-mercaptoethylthio) -1,3,5-triazine, 2,4-di (2-mercaptoethylthio)-
6-mercapto-1,3,5-triazine, 2,6-di (2-mercaptoethylthio) -4-mercapto-1,
3,5-triazine, 4,6-di (2-mercaptoethylthio) -2-mercapto-1,3,5-triazine,
2,4,6-tri (5-mercapto-3-thiapentathio) -1,3,5-triazine, 2,4-di (5-mercapto-3-thiapentathio) -6-mercapto-1,
3,5-triazine, 2,6-di (5-mercapto-3
-Thiapentathio) -4-mercapto-1,3,5-triazine, 4,6-di (5-mercapto-3-thiapentathio) -2-mercapto-1,3,5-triazine,
2,4-di (5-mercapto-3-thiapentathio)-
6- (2-mercaptoethylthio) -1,3,5-triazine, 2,6-di (5-mercapto-3-thiapentathio) -4- (2-mercaptoethylthio) -1,3
5-triazine, 4,6-di (5-mercapto-3-thiapentathio) -2- (2-mercaptoethylthio)-
1,3,5-triazine, 4- (5-mercapto-3-
Thiapentathio) -2,6-dimercapto-1,3,5
-Triazine, 2-mercapto-4- (5-mercapto-3-thiapentathio) -6- (2-mercaptoethylthio) -1,3,5-triazine, 2,4,6-tri (8-mercapto-3) , 6-thiapentathio) -1,
3,5-triazine, 2,4,6-tri (11-mercapto-3,6,9-trithiaundecathio) -1,3,3
5-triazine, 2,4,6-tri (14-mercapto-3,6,9,12-tetrathiatetradecathio)-
1,3,5-triazine, 2- (5-mercapto-3-
Thiapentathio) -4,6-di (8-mercapto-3,
6-dithiaoctathio) -1,3,5-triazine,
2,4-di (5-mercapto-3-thiapentathio)-
6- (8-mercapto-3,6-dithiaoctathio)-
1,3,5-triazine, 2- (2-mercaptoethylthio) -4- (5-mercapto-3-thiapentathio)
-6- (8-Mercapto-3,6-dithiaoctathio)
-1,3,5-triazine, 4,6-di (11-mercapto-3,6,9-trithiaundecathio) -2- (5
-Mercapto-3-thiapentathio) -1,3,5-triazine, 2- (5-mercapto-3-thiapentathio) -4- (8-mercapto-3,6-dithiaoctathio) -6- (11-mercapto-3 , 6,9-Trithiaundecathio) -1,3,5-triazine, 2- (2-
Mercaptoethylthio) -4- (5-mercapto-3-
Thiapentathio) -6- (11-mercapto-3,6
9-Trithiaundecathio) -1,3,5-triazine, 2,4-di (5-mercapto-3-thiapentathio) -6- (11-mercapto-3,6,9-trithiaundecathio)- 1,3,5-triazine, 2,4-di (5-mercapto-3-thiapentathio) -6- (14
-Mercapto-3,6,9,12-tetrathiatetradecathio) -1,3,5-triazine, 2- (5-mercapto-3-thiapentathio) -4- (8-mercapto-
3,6-Dithiaoctathio) -6- (14-mercapto-3,6,9,12-tetrathiatetradecathio)-
1,3,5-triazine, 2- (5-mercapto-3-
Thiapentathio) -4- (11-mercapto-3,6
9-Trithiaundecathio) -6- (14-mercapto-3,6,9,12-tetrathiatetradecathio)-
1,3,5-triazine, 4,6-di (14-mercapto-3,6,9,12-tetrathiatetradecathio)-
2- (5-mercapto-3-thiapentathio) -1,
3,5-triazine and the like can be mentioned. The thiol compound is not limited to these compounds. You may use these thiol compounds individually or in mixture of 2 or more types.

Further, 4,4'-bis (mercaptomethyl) phenyl sulfide, 4,4'-bis (4-mercapto-2-thiabutyl) phenyl sulfide and 4,4'-bis (4-mercapto-2-thiabutyl) phenyl sulfide
4'-bis (7-mercapto-2,5-dithiaheptyl) phenyl sulfide is a solid at room temperature.

From the viewpoint of workability and properties, such room-temperature solid thiol compounds are not used alone, but other thiol compounds or copolymerized unsaturated compounds such that they are liquid rather than solid at room temperature. It is preferable to use it in combination with a compound having two or more double bonds.

Among these thiol compounds, when the compound having the above-mentioned phenyl sulfide structure is contained, the refractive index is significantly improved due to both the phenyl group and the sulfide structure.

Further, tetrakis- (7-mercapto-
Aliphatic thiol compounds such as 2,5-dithiaheptyl) methane are preferable because they are liquid at room temperature and have excellent compatibility, and the cured product has high transparency.

Further, tetrakis- (7-mercapto-
2,5-dithiaheptyl) methane also has a skeleton represented by the formula (1), imparts flexibility to the cured product, and improves adhesive strength, which is particularly preferable.

Examples of the compound having two or more unsaturated double bonds used in the present invention include aromatic vinyl compounds and (meth) acrylic acid derivatives. As the aromatic vinyl compound, divinylbenzene,
Bis (4-vinylthiophenyl) sulfide, bis (4
-Vinylthiomethylphenyl) sulfide, 2,4
4'-tri (vinylthiomethyl) phenyl sulfide and the like can be mentioned. In particular, it is preferable to use a compound having a phenyl sulfide structure such as bis (4-vinylthiophenyl) sulfide because the refractive index of the cured product is significantly improved.

As the (meth) acrylic acid derivative, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (Meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth)
Acrylate, 1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (or tetra) ) (Meth) acrylate, compounds having sulfur in the structure, bis (4-methacryloylthiophenyl) sulfide, and (meth) acryl-terminated aliphatic sulfide having the structure of formula (1). In addition, bis (4-methacryloylthiophenyl) sulfide, bis (3-methyl-4-methacryloylthiophenyl) sulfide, bis (3,5
-Dimethyl-4-methacryloylthiophenyl) sulfide, bis (2,3,5,6-tetramethyl-4-methacryloylthiophenyl) sulfide, bis (3-hexyl-4-methacryloylthiophenyl) sulfide,
Bis (3,5-dihexyl-4-methacryloylthiophenyl) sulfide, bis (3-chloro-4-methacryloylthiophenyl) sulfide, bis (3,5-dichloro-4-methacryloylthiophenyl) sulfide,
Bis (2,3,5,6-tetrachloro-4-methacryloylthiophenyl) sulfide, bis (3-bromo-4)
-Methacryloylthiophenyl) sulfide, bis (3,5-dibromo-4-methacryloylthiophenyl) sulfide, bis (2,3,5,6-tetrabromo-4-methacryloylthiophenyl) sulfide, preferably bis (4- Methacryloylthiophenyl) sulfide, bis (2,3,5,6-tetrachloro-4-methacryloylthiophenyl) sulfide, bis (2,2
3,5,6-Tetrabromo-4-methacryloylthiophenyl) sulfide and the like can also be mentioned, and further compounds such as bis (2-vinylthioethyl) sulfide and 2,4′-bis (vinylthiomethyl) sulfide can also be mentioned. You can also

Further, a polyfunctional (meth) acrylic oligomer which can be used for general adhesive formulation can also be used,
It is possible to improve the adhesive strength. The compounds having two or more unsaturated double bonds may be used alone or in combination of two or more, and are not limited to these. In particular, it is preferable to use a compound having an unsaturated double bond having sulfur in its structure because the refractive index can be further improved.

Further, the use of the (meth) acrylic-terminated aliphatic sulfide having the structure of the formula (1) is more preferable because the refractive index and the adhesive strength can be improved and the Abbe number can be increased.

The copolymerization of the mercapto compound having two or more thiol terminal groups with the compound having two or more unsaturated double bonds is carried out by combining two reactions of a thiol / ene polymerization reaction and a radical polymerization reaction, A good cured product can be provided. The reaction equivalent ratio of the mercapto compound having two or more thiol terminal groups to the compound having two or more unsaturated double bonds is preferably 1: 1 to 1: 5. When it is 1: 1 or less, unreacted thiol compound is present in the cured product, and curing becomes insufficient, which is not preferable. Further, when it is 1: 5 or more, the polymerization of the compound having an unsaturated double bond is prioritized, the cured product becomes poor in flexibility, and the adhesive strength decreases, which is not preferable.

In particular tetrakis- (7-mercapto-2,
When 5-dithiaheptyl) methane is copolymerized with a (meth) acryl-terminated aliphatic sulfide having the structure of formula (1), a cured product having a high refractive index and a high Abbe number can be obtained, and the adhesive strength is also high. Because it can be improved
Particularly preferred.

Examples of the photopolymerization initiator used in the present invention include 2,2-diethoxyacetophenone and 2,2-diethoxyacetophenone.
2-diethoxy-2-phenylacetophenone, benzophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one,
Benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2 -Hydroxy-2-methyl-1-phenyl-propane-1-
On, 1- (4-hydroxyethoxy) -phenyl-2
-Hydroxy-2-methyl-1-propan-1-one,
2-methyl-1- (4- (methylthio) phenyl) -2
-Morpholinopropan-1-one, 2-benzyl-2
-Dimethylamino-1- (4-morpholinophenyl)
-Butanone-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,2
6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (η5-2,4-cyclopentadien-1-yl)- Bis (2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium, 4,4-bisdimethylaminobenzophenone, methylbenzoisoformate, benzyldimethylketal, benzoylbenzoic acid, 2-chlorothioxanthone , 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone and the like.

Particularly, photoradical polymerization initiators which are compatible with liquid or liquid initiators include 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone. Eutectic compound, a mixed compound of bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2 A mixed compound of 4,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one and the like are mentioned, but not limited thereto. In addition, these may be used alone or in combination of two or more kinds.

As an initiator having a light absorption of 405 nm or more, 2-benzyl-2-dimethylamino-1-
(4-morpholinophenyl) -butanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 and 2,2-dimethoxy-1,
2-diphenylethan-1-one mixed compound, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine A mixed compound of oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one, bis (2,6
-Dimethoxybenzoyl) -2,4,4-trimethyl-
A mixed compound of pentylphosphine oxide and 1-hydroxy-cyclohexyl-phenyl-ketone, 2,
A mixed compound of 4,6-trimethylbenzoyl-diphenyl-phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one, bis (η5
-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium. This 405n
An initiator having an absorption of m or more and the other initiators described above can be used in combination, and more uniform curability can be imparted, and in particular, uniformity can be imparted in the depth direction, which is preferable.

Among them, particularly, an initiator containing a phosphorus-based initiator, and a liquid system includes bis (2,6-
Dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide and 2-hydroxy-2-
Methyl-1-phenyl-propan-1-one mixed compound, 2,4,6-trimethylbenzoyl-diphenyl-
A mixed compound of phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one is mentioned, and a compound which is more transparent and has a good deep-curing property can be obtained, which is preferable.

The thermal polymerization initiator used in combination includes, for example, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobisisobutyronitrile, 2,
2'-azobisisovaleronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, Examples thereof include benzoyl peroxide and 2,4-dichlorobenzoyl peroxide.

The amount of these initiators added depends on the type of initiator,
Although it cannot be unconditionally determined because it depends on the type and composition ratio of the compound to be blended, it is preferably in the range of 0.5 to 6% by weight based on the total amount of the adhesive composition. Particularly preferably 1
Is in the range of up to 3% by weight. If it is less than 0.5% by weight, the curability is poor and unreacted matter remains, resulting in poor adhesion. Also,
If it exceeds 6% by weight, the degree of polymerization becomes low, the cured product becomes too soft, and the adhesiveness decreases, which is not preferable. 1
When the content is ˜3% by weight, an adhesive composition having particularly good curability and high adhesiveness can be provided.

Examples of the silane coupling agent used in the present invention include, specifically, silane coupling agents such as γ-aminopropyltriethoxysilane and N-β- (aminoethyl) -γ-. Aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane,
Aminosilane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane and γ-ureidopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy Epoxy silane coupling agents such as silane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) Vinylsilane coupling agents such as silane, γ-mercaptopropyltrimethoxysilane, mercaptosilane coupling agents such as γ-mercaptopropylmethyldimethoxysilane, γ-methacryloyloxypropyltrimethoxy Acrylic silane coupling agents such as silane, methyl trimethoxy silane, methyl triethoxy silane, .gamma.-chloropropyl trimethoxy silane, in the general formula RSi (OR ') ₃ [Formula such as a trifluoromethyl trimethoxy silane, R represents 1 Shows a linear or branched alkyl group having about 1 to 4 carbon atoms which may be substituted with one or two or more halogen atoms, and R ′ represents 1 to 4 carbon atoms.
A linear or branched alkyl group of about 4 is shown. ] An alkyl trialkoxy silane etc. which are represented by these can be mentioned. These may be used alone or in combination of two or more, and are not limited to these compounds.

Particularly, the mercaptosilane coupling agent γ
-Mercaptopropyltrimethoxysilane and γ-mercaptopropylmethyldimethoxysilane have good compatibility with sulfur-based compounds and are preferable for improving the adhesion to a member such as glass. Further, since these mercaptosilane coupling agents contain a sulfur atom, there is little decrease in the refractive index due to the compounding, and it is more preferable.

The amount of these silane coupling agents added is
Although it varies greatly depending on the photocurable adhesive composition of the present invention, 0.1 to 10 parts by weight is preferable when the total amount of the photocurable adhesive composition is 100 parts by weight. If it is less than 0.1 part by weight, the wettability is lowered and the curing acceleration effect is poor, and the adhesive strength is lowered. On the other hand, if it exceeds 10 parts by weight, the cohesive force of the resin is lowered, and the adhesive strength and reliability are lowered. These blends interact with each other and are effective in controlling viscosity before curing, photo-curing property, post-heat curing property, curing shrinkage property, and adhesive property, and it is possible to achieve characteristics that are difficult to be expressed only by each blending type.

Next, the curing method and bonding method of the photocurable adhesive composition will be described in more detail. First, regarding the amount of ultraviolet irradiation of the photocurable adhesive resin composition, it varies depending on the adhesive composition, and thus is determined by each curing condition. It is sufficient that the photocurable adhesive composition is cured at an irradiation dose, and it is sufficient that the curing conditions satisfy the adhesive strength of the cured product. Further, when used in combination with heat curing, it is possible to improve the curing speed, the curability, and the adhesive strength. One is a method of improving the curing speed by performing heat curing at the same time as photocuring to improve the curability, and another method is to heat the cured product to Tg or more and the thermal polymerization initiator cleavage temperature or more after irradiation. This is a method of curing the radical-reactive compound remaining as an unreacted substance by only light irradiation by post-curing to improve the curability and improve the adhesive strength.

Although it varies depending on the composition of the photocurable adhesive composition, the higher the temperature range is, the more effective the promotion of curing after light irradiation is, and the shorter the heat treatment is. Also,
The lower the temperature, the longer the heat treatment. Such thermal after-curing also has an effect of aging the moisture, the adhered organic matter and the unreacted impurities.

It should be noted that the pot life contains a photo radical initiator, and if it is not irradiated with light, the polymerization is difficult to start, and it is long and has good workability. However, the photocurable adhesive composition in which a thermal radical polymerization initiator is used in combination needs to be stored in a cool and dark place, and frozen storage is particularly preferable in terms of pot life. Further, when describing the coating method of these adhesive compositions, although it varies depending on each site and member, it may be a commonly used uniform coating method, for example, a screen printing method, a spin coating method, a transfer method, a dispenser method, or the like. However, the present invention is not limited to these. The viscosity of the photocurable adhesive composition of the present invention can be adjusted according to these methods, which is effective.

Further, particularly when the curing reaction is difficult to proceed due to no light when the members are adhered, a heat polymerization initiator is used in combination in this photocurable adhesive composition to perform heat treatment after light irradiation. Since the reaction can be completed and the reaction can be completed completely, the adhesive strength is high and the unreacted material does not adversely affect other parts. In this way, it is possible to adhere according to the application.

[0048]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples of photocurable optical adhesive compositions. In the following, "part" and "%" are based on weight.
The resulting photocurable optical adhesive composition was evaluated by the following tests. (Optical Adhesive Composition Evaluation Method) The components described below were mixed and stirred to prepare an optical adhesive composition.
This composition was cured under the following conditions, and its refractive index, Abbe number, light transmittance, photocurability, and adhesive strength were evaluated. Curing conditions are 100 mW / cm ² UV irradiation, 3 J / c
It was cured by photopolymerization at m ² . Furthermore, in the case of using a thermal polymerization initiator together, thermal after cure curing is performed at 100 ° C.
It was heated for 3 hours. (I) Curability: Coat on a glass plate and apply 3 with a high pressure mercury lamp.
J / cm ² irradiation and cured by visual evaluation were evaluated as ◯, only the surface was cured, or those having a sticky surface were evaluated as Δ, and those not cured at all were evaluated as x. (Ii) Adhesion: Compressive shear strength test glass / glass (Pyrex (registered trademark) glass plate:
20mm x 25mm x 5mm) bonded (bonded area: 2c
After m ² ), the compressive shear strength was measured at a speed of 1 mm / min. ◯: 20 kgf / cm ² or more, Δ: 10 to 20 kgfc
m ^{2 or} less, x: less than 10 kgf / cm ² (iii) Adhesion reliability: compressive shear strength test After curing adhesion, the sample was subjected to an environmental test (80 ° C. 4 h and 60
After carrying out the test at 60 ° C. for 100 h), a compressive shear strength test was conducted. ◯: 20 kgf / cm ² or more, Δ: 10 to 20 kgfc
less than m ² , x: less than 10 kgf / cm ² (iv) Refractive index and Abbe number: 2 using Abbe refractometer
It was measured at 5 ° C. (V) Light transmittance: curing the adhesive composition to a thickness of 1 mm,
The sheet was measured with a spectrophotometer. (Wavelength 800n
m). Transmittance / 80% or more: ○, 60 to less than 80%: Δ, 60
%: Less than x Table 1 shows the evaluation results of the examples of the respective adhesive compositions. The respective formulations are shown in the examples below.

[0049] Example 1   4,4'-bis (mercaptomethyl) phenyl sulfide 40 parts by weight   60 parts by weight of ethylene glycol diacrylate   Eutectic of 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone Compound (I500 manufactured by Ciba Specialty Chemicals) 2 parts by weight   γ-methacryloyloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) 3 parts by weight

[0050] Example 2   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             50 parts by weight   50 parts by weight of trimethylolpropane triacrylate   Eutectic of 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone Compound (I500 manufactured by Ciba Specialty Chemicals) 2 parts by weight   γ-methacryloyloxypropylmethyldimethoxysilane (Shin-Etsu Chemical KBM502) 5 parts by weight

[0051] Example 3   4,4'-thiol dibenzenethiol 30 parts by weight   70 parts by weight of 1,4-butanediol dimethacrylate   Eutectic of 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone Compound (I500 manufactured by Ciba Specialty Chemicals) 3 parts by weight   γ-methacryloyloxypropylmethyldiethoxysilane (Shin-Etsu Chemical KBE502) 5 parts by weight

[0052] Example 4   4,4'-thiol dibenzenethiol 20 parts by weight Methacryl-terminated aliphatic sulfide having the structure of formula (1) (S2EG manufactured by Sumitomo Seika) 80 parts by weight   Eutectic of 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone Compound (I500 manufactured by Ciba Specialty Chemicals) 3 parts by weight   γ-methacryloyloxypropyltriethoxysilane (KBE manufactured by Shin-Etsu Chemical) 503) 3 parts by weight

[0053] Example 5   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             50 parts by weight   Bis (4-methacryloylthiophenyl) sulfide 20 parts by weight   Bis (4-vinylthiophenyl) sulfide 30 parts by weight   Eutectic of 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone Compound (I500 manufactured by Ciba Specialty Chemicals) 3 parts by weight   γ-methacryloyloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) 3 parts by weight

[0054] Example 6   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             50 parts by weight   Bis (4-vinylthiophenyl) sulfide 50 parts by weight   2-hydroxy-2-methyl-1-phenyl-propan-1-one (C117 Specialty Chemicals D1173) 2 parts by weight   γ-methacryloyloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) 2 parts by weight

[0055] Example 7   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             10 parts by weight   Methacryl-terminated aliphatic sulfide having the structure of formula (1) (S2EG manufactured by Sumitomo Seika) 90 parts by weight   Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propa N-1-one 1: 3 mixed compound (Ciba Specialty Chemicals I1700) 2 parts by weight   γ-methacryloyloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) 2 parts by weight

[0056] Example 8   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             10 parts by weight   Methacryl-terminated aliphatic sulfide having the structure of formula (1) (S2EG manufactured by Sumitomo Seika) 50 parts by weight   Bis (4-methacryloylthiophenyl) sulfide 20 parts by weight Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphen Phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propane -1-one 1: 3 mixed compound (Ciba Specialty Chemicals I1700) 2 parts by weight   γ-methacryloyloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) 2 parts by weight

[0057] Example 9   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             20 parts by weight   Methacryl-terminated aliphatic sulfide having the structure of formula (1) (S2EG manufactured by Sumitomo Seika) 70 parts by weight   Bis (4-vinylthiophenyl) sulfide 10 parts by weight   Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propa N-1-one 1: 3 mixed compound (Ciba Specialty Chemicals I1700) 2 parts by weight   γ-Mercaptopropylmethyldimethoxysilane (Shin-Etsu Chemical KBM802) 5 parts by weight

[0058] Example 10   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             30 parts by weight   Methacryl-terminated aliphatic sulfide having the structure of formula (1) (S2EG manufactured by Sumitomo Seika) 70 parts by weight (The above reaction equivalence ratio = 1: 3)   Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propa N-1-one 1: 3 mixed compound   (Ciba Specialty Chemicals I1700) 2 parts by weight γ-mercaptopropyltrimethoxysilane (Shin-Etsu Chemical KBM803) 2 parts by weight

[0059] Example 11   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                             30 parts by weight   Methacryl-terminated aliphatic sulfide having the structure of formula (1) (S2EG manufactured by Sumitomo Seika) 70 parts by weight   With 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide 2-Hydroxy-2-methyl-1-phenyl-propan-1-one 1: 1 mixture Compound (Ciba Specialty Chemicals D4265: Absorption of 405 nm or more and 365n m or less absorption initiator mixed type) 2 parts by weight   γ-mercaptopropyltrimethoxysilane (Shin-Etsu Chemical KBM803) 2 parts by weight

Example 12 Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane 30 parts by weight Methacryl-terminated aliphatic sulfide having the structure of formula (1) (S2EG manufactured by Sumitomo Seika) 70 parts by weight 2,4 1: 1 mixed compound of 6-trimethylbenzoyl-diphenyl-phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Ciba Specialty Chemicals D4265: absorption above 405 nm and absorption below 365 nm) Agent mixing type) 2 parts by weight 2,2'-azobisisovaleronitrile (thermal polymerization initiator) 1 part by weight γ-mercaptopropyltrimethoxysilane (KBM803 manufactured by Shin-Etsu Chemical Co., Ltd.) 2 parts by weight 100 after 5 hours of light irradiation The temperature was raised to 100 ° C and the temperature was maintained at 100 ° C for 3 hours.

[0061] Comparative Example 1   Tetrakis- (7-mercapto-2,5-dithiaheptyl) methane                                                           100 parts by weight   Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propa N-1-one 1: 3 mixed compound (Ciba Specialty Chemicals I1700) 2 parts by weight   γ-methacryloyloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) 2 parts by weight

[0062] Comparative example 2   Bis (4-methacryloylthiophenyl) sulfide 100 parts by weight   Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propa N-1-one 1: 3 mixed compound (Ciba Specialty Chemicals I1700) 2 parts by weight   γ-methacryloyloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) 2 parts by weight

[0063] Comparative Example 3   Bis (4-vinylthiophenyl) sulfide 100 parts by weight   2-hydroxy-2-methyl-1-phenyl-propan-1-one (C117 Specialty Chemicals D1173) 2 parts by weight

[0064] Comparative Example 4   Bis (4- (2,3-epoxythio) phenyl) sulfide 100 parts by weight   Aromatic sulfonium salt polymerization initiator / photocationic initiator (Asahi Denka, SP-170) 5 parts by weight   γ-glycidoxypropylmethyldiethoxysilane (Shin-Etsu Chemical KBE402) 5 parts by weight

[0065]

[Table 1]

[0066]

INDUSTRIAL APPLICABILITY The present invention provides a photocurable optical adhesive composition which has a high refractive index, good curability and high adhesive strength, and is particularly suitable for use as a photocurable adhesive. it can. According to claim 1, a photocurable optical adhesive containing at least a mercapto compound having two or more thiol terminal groups, a compound having two or more unsaturated double bonds, a photopolymerization initiator and a silane coupling agent. The agent composition can provide a photocurable optical adhesive composition having a high refractive index and a high adhesive strength.

According to the second aspect, the mercapto compound having two or more thiol terminal groups has at least the structure of the formula (1). , A photocurable optical adhesive composition having high adhesive strength is provided, and in particular, by containing the structure of formula (1), the flexibility of the cured product can be increased and the adhesive strength can be improved. Since the number of sulfur atoms in the composition increases, it is possible to provide a photocurable optical adhesive composition capable of improving the refractive index and the Abbe number.

According to the third aspect, a mercapto compound having two or more thiol terminal groups contains at least a phenyl sulfide structure, and a photocurable adhesive composition for optics is used to bond with a high refractive index. A high-strength photocurable adhesive composition for optics is provided. In particular, a compound having a phenyl sulfide or phenyl disulfide structure is contained, so that the compound has a sulfur atom and an aromatic molecular structure, so that it has a large refractive index. It is possible to provide a photocurable optical adhesive composition capable of improving the rate.

According to claim 4, the compound having two or more unsaturated double bonds to be copolymerized with the mercapto compound having two or more thiol end groups contains at least the structure of the formula (1). A photocurable optical adhesive composition having a high refractive index and a high adhesive strength is provided by the photocurable optical adhesive composition, and in particular, a cured product is obtained by containing the structure of the formula (1). To provide a photo-curable optical adhesive composition capable of increasing the flexibility, improving the adhesive strength, increasing the number of sulfur atoms in the compound, and greatly improving the refractive index and the Abbe number. You can

According to the fifth aspect, the compound having two or more unsaturated double bonds to be copolymerized with the mercapto compound having two or more thiol terminal groups contains at least a phenyl sulfide structure, so that a high refractive index can be obtained. , A photocurable optical adhesive composition having high adhesive strength is provided, and in particular, a compound having a phenyl sulfide or a phenyl disulfide structure is contained, so that the compound has a sulfur atom and an aromatic molecular structure, It is possible to provide a photocurable optical adhesive composition capable of greatly improving the refractive index.

According to the sixth aspect, since the photopolymerization initiator is at least a liquid or a photoradical polymerization initiator compatible with the liquid initiator, the photocurable optical adhesive having a high refractive index and a high adhesive strength. An agent composition is provided, and in particular, it is possible to provide a photocurable optical adhesive composition which prevents opacity due to a residue of a photoinitiator and imparts transparency to a cured product.

According to the seventh aspect, since the photo-radical polymerization initiator which is liquid or compatible with the liquid initiator contains at least a phosphorus-based photo-polymerization initiator, it has a high refractive index.
Provided is a photocurable optical adhesive composition having high adhesive strength, in particular, a photocurable optical adhesive which prevents opacity due to a residue of a photoinitiator, imparts transparency to a cured product, and makes a curing reaction uniform. An agent composition can be provided.

According to the eighth aspect, by using a compound in which a compound having two or more unsaturated double bonds is liquid or compatible with the liquid compound at room temperature, photocuring with high refractive index and high adhesive strength is achieved. Provided is an optical adhesive composition for optical molds, and in particular, it is possible to provide a photocurable optical adhesive composition having good compatibility between copolymerized monomers, imparting transparency to a cured product, and making the curing reaction uniform. it can.

According to the ninth aspect, by using a compound in which a mercapto compound having two or more thiol terminal groups is liquid at room temperature or compatible with the liquid compound, a photocurable type having a high refractive index and a high adhesive strength is used. An optical adhesive composition is provided, and in particular, it is possible to provide a photocurable optical adhesive composition that has good compatibility between copolymerized monomers, imparts transparency to a cured product, and makes the curing reaction uniform. .

According to the tenth aspect, the silane coupling agent contains a sulfur atom in at least the molecular structure, whereby a photocurable optical adhesive composition having a high refractive index and a high adhesive strength is provided. In particular, the invention provides a photocurable optical adhesive composition that has an effect on the adhesiveness between glass and a cured product, has good compatibility with the cured product because it contains a sulfur atom, and also has an effect of improving the refractive index. You can

According to the eleventh aspect, the reaction equivalence ratio of the thiol terminal group to the unsaturated double bond in the photocurable optical adhesive composition is from 1: 1 to 1: 5, which results in a high refractive index. And, a photocurable optical adhesive composition having high adhesive strength is provided, and particularly, a curing reaction is uniform and gives a good cured product, and a photocurable optical adhesive composition having good adhesive strength is provided. be able to.

According to claim 12, the light absorption is 405 nm.
By using the photopolymerization initiator also having the above and the photopolymerization initiator having a wavelength of 365 nm or less in combination, a photocurable optical adhesive composition having a high refractive index and a high adhesive strength is provided, and particularly a curing reaction is uniform. It is possible to provide a photocurable optical adhesive composition having a high adhesive strength, which enables the inside of the cured product to be cured well.

According to the thirteenth aspect, by using the photopolymerization initiator and the thermal polymerization initiator in combination, a photocurable optical adhesive composition having a high refractive index and a high adhesive strength is provided. It is possible to provide a better cured product by heating after curing or simultaneous heating with light irradiation, and to provide a photocurable optical adhesive composition having high adhesive strength.

Continued front page    F-term (reference) 4J030 BA04 BB07 BB62 BC43 BF14                       BG03                 4J040 EK052 EK072 EK082 FA041                       FA141 FA161 GA24 HD03                       HD05 HD21 HD31 HD32 JA01                       KA13 LA06 LA10 NA18

Claims (13)

[Claims] 1. A photocurable type comprising at least a mercapto compound having two or more thiol terminal groups, a compound having two or more unsaturated double bonds, a photopolymerization initiator and a silane coupling agent. Optical adhesive composition. 2. The photocurable optical adhesive composition according to claim 1, wherein the mercapto compound having two or more thiol terminal groups has at least the structure of the general formula (1). [Chemical 1] (N represents an integer of 1 or more) 3. The photocurable optical adhesive composition according to claim 1, wherein the mercapto compound having two or more thiol terminal groups has at least a phenyl sulfide structure. 4. The photo-curable optical adhesive according to claim 1, wherein the compound having two or more unsaturated double bonds has at least the structure represented by the general formula (1). Agent composition. 5. The photocurable optical adhesive composition according to claim 1, wherein the compound having two or more unsaturated double bonds has at least a phenyl sulfide structure. 6. The photocurable optical adhesive according to claim 1, wherein the photopolymerization initiator is at least a liquid or a photoradical polymerization initiator compatible with the liquid initiator. Composition. 7. The photocurable optical adhesive according to claim 6, wherein the photoradical polymerization initiator compatible with a liquid or a liquid initiator contains at least a phosphorus photopolymerization initiator. Composition. 8. The photocurable optical adhesive according to claim 1, wherein the compound having two or more unsaturated double bonds is compatible with a liquid or a liquid initiator at room temperature. Agent composition. 9. The photocurable optical adhesive composition according to claim 1, wherein the mercapto compound having two or more thiol terminal groups is compatible with a liquid or a liquid initiator at room temperature. object. 10. The photocurable optical adhesive composition according to claim 1, wherein the silane coupling agent contains at least a sulfur atom in its molecular structure. 11. The reaction equivalent ratio of the thiol terminal group and the unsaturated double bond in the photocurable optical adhesive composition is 1: 1 to 1: 5. The photocurable optical adhesive composition according to any one of the above. 12. A photopolymerization initiator having a light absorption at a wavelength longer than 405 nm and a photopolymerization initiator having a light absorption at a wavelength shorter than 365 nm are used in combination. The light-curable optical adhesive composition described. 13. The curable optical adhesive composition according to any one of claims 1 to 12, wherein a photopolymerization initiator and a thermal polymerization initiator are used in combination.