JP2000038547A - Photocuring adhesive composition and optical member using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocuring adhesive which is of the one-pack curable type, easy to handle, free from discharge of a solvent or the like curable in a short period of time and high in bonding strength. SOLUTION: This photocuring adhesive composition comprises (A) 5-70 pts.wt. urethane polymer having two or more (meth)acryloxy groups in the molecule, (B) 30-95 pts.wt. monofunctional (meth)acrylate, (C) 0-40 pts.wt. polyfunctional (meth)acrylate, and (D) 0.01-5 pts.wt. [provided that the sum of components (A)-(C) is 100 pts.wt.] photopolymerization initiator. An optical member is obtained by laminating sheet lenses with the adhesive composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable adhesive composition useful for bonding a transparent member such as an organic glass or an inorganic glass, and an optical member using the same.

[0002]

2. Description of the Related Art Conventionally, epoxy-based adhesives and urethane-based adhesives have been used as adhesives used for bonding organic glasses, inorganic glasses, or a combination thereof. As the two-component mixed-curable adhesive, for example, a two-component reactive adhesive described in JP-A-58-149971 can be mentioned. As the thermosetting adhesive, for example, JP-A-52-133337 can be used. The solvent-based adhesive includes, for example, JP-A-63-163
An example of the adhesive composition is described in JP-A-83182.

[0003]

The two-component mixed-curing adhesive is used by measuring and mixing two materials at the time of use. Therefore, although the pot life is longer than that of the one-component curable adhesive, it takes time to use. In addition, since the thermosetting adhesive takes a long time to cure, the workability at the time of bonding is poor and the productivity of the product is low. Further, the organic solvent of the solvent-type adhesive is not preferable in terms of environment and occupational health.

An object of the present invention is to provide a light-curing adhesive which is a one-part curing type, which is easy to handle, does not discharge a solvent or the like, cures in a short time, and has high adhesive strength. An object of the present invention is to provide an optical member used.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a urethane polymer having two or more (meth) acryloyloxy groups in one molecule and a monofunctional (meth) acrylate It has been found that the use of a composition containing at least an extremely effective effect can be obtained, and the present invention has been completed.

That is, according to the present invention, the urethane polymer (A) having two or more (meth) acryloyloxy groups in one molecule is 5 to 70 parts by weight, the monofunctional (meth) acrylate (B) is 30 to 95 parts by weight, 0 to 40 parts by weight of the functional (meth) acrylate (C) and 0.1 part of the photopolymerization initiator (D).
It is a photocurable adhesive composition comprising from 0.1 to 5 parts by weight [100 parts by weight in total of components (A), (B) and (C)].

In the present invention, "(meth) acrylate" means "acrylate and / or methacrylate".

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

The urethane polymer (A) having two or more (meth) acryloyloxy groups in one molecule used in the present invention includes, for example, (meth) acryloyl at the molecular terminals and / or side chains of various polymers or copolymers. Examples include those obtained by introducing an oxy group.

As a method for producing the urethane polymer (A), for example, the following two production methods can be mentioned.

In the first production method, a polyol having two or more hydroxyl groups at a molecular terminal and / or a side chain and a polyisocyanate having two or more isocyanate groups in a molecule are subjected to a urethanization reaction. A method of reacting an isocyanate group remaining in the polyurethane with a hydroxyl group-containing (meth) acrylate.

The polyol having two or more hydroxyl groups at the molecular terminal and / or the side chain used herein includes, for example, polyester polyol, polyether polyol, polycarbonate diol, acrylic polyol, polybutadiene polyol, phenolic polyol, epoxy polyol And the like.

Examples of the polyisocyanate having two or more isocyanate groups in the molecule used herein include aliphatic isocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene triisocyanate and undecane triisocyanate; Aromatic isocyanates such as xylylene diisocyanate, tetramethyl xylylene diisocyanate, and diphenylmethane diisocyanate; alicyclic isocyanates such as isophorone diisocyanate, dicyclohexylmethane diisocyanate, and bicycloheptane triisocyanate;

The hydroxyl group-containing (meth) used herein
As the acrylate, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, and the like.

The second production method comprises the steps of urethane-forming a compound having an isocyanate group and a (meth) acryloyloxy group in a molecule, such as (meth) acryloyloxy isocyanate and 2- (meth) acryloyloxyethyl isocyanate, and a polyol. It is a method of reacting.

In the first and second production methods described above, the molecular weights and types of the raw materials such as polyol, polyisocyanate, and hydroxyl group-containing (meth) acrylate, and each of these raw materials may be used alone or in combination of two or more. It is possible to easily obtain urethane polymers (A) having different properties and molecular weights by appropriately selecting whether or not to use together.

The molecular weight of the urethane polymer (A) is not particularly limited, and may be appropriately selected according to the use and the like. The adjustment of the molecular weight can be carried out by changing the molar ratio of the raw materials polycisocyanate and polyol at the time of charging, or by dropping polyisocyanate into polyol, or dropping polyol into polyisocyanate. According to these adjustment methods, a urethane polymer having an arbitrary molecular weight can be obtained even when the same kind of starting compound is used.

The weight average molecular weight of the urethane polymer (A) is preferably 1500 or more from the viewpoint of exhibiting higher adhesive strength. Further, from the viewpoint of facilitating synthesis and handling, the weight average molecular weight is preferably 1,000,000 or less. The weight average molecular weight is a value determined by GPC (in terms of polystyrene).

The amount of the urethane polymer (A) used is
With respect to 100 parts by weight of the total of components (A) to (C),
70 parts by weight, preferably 15 to 60 parts by weight. If this amount is less than 5 parts by weight, the curability will be poor and the productivity during the bonding operation will be reduced. In addition, the cohesive strength of the adhesive composition is insufficient, so that cohesive failure is apt to occur, whereby the adhesive strength tends to decrease. On the other hand, if the amount exceeds 70 parts by weight, the viscosity of the composition tends to be high, and the workability during the bonding operation tends to decrease.

The monofunctional (meth) acrylate (B) used in the present invention plays a role as a reactive diluent, and exhibits excellent adhesive strength when used in combination with the urethane polymer (A).

The monofunctional (meth) acrylate (B) is
It is a compound having one (meth) acryloyloxy group, and may be appropriately selected from conventionally known monofunctional (meth) acrylates according to the use of the adhesive. In particular,
It is preferable to use one or more monofunctional (meth) acrylates in combination in consideration of the adhesive strength to the adherend, transparency after curing, refractive index, and the like. For example, a (meth) acrylate having a hydroxyl group is particularly effective for improving the adhesive strength to glass.

Specific examples of the monofunctional (meth) acrylate (B) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate,
1-butyl (meth) acrylate, t-butyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy Propyl (meth) acrylate,
Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth)
Acrylate, tricyclo [5 · 2 · 1 · 0 ^2.6] decanyl (meth) acrylate.

Particularly, specific examples of the (meth) acrylate having a hydroxyl group include hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, and hydroxypropyl (meth) acrylate. These may be used alone or in combination of two or more.

The amount of the monofunctional (meth) acrylate (B) used is 30 to 95 parts by weight, preferably 40 to 85 parts by weight, based on 100 parts by weight of the total of the components (A) to (C). is there. If the amount is less than 30 parts by weight, the viscosity of the composition tends to be high, and the workability during the bonding operation tends to decrease. On the other hand, when the amount exceeds 95 parts by weight, the adhesive composition has insufficient cohesive strength, which tends to cause cohesive failure, which tends to reduce the adhesive strength.

The polyfunctional (meth) acrylate (C) used in the present invention is a compound having two or more (meth) acryloyloxy groups, which controls the crosslink density, improves the curability,
It plays a role in adjusting the refractive index and improving the adhesive strength.

Specific examples of the polyfunctional (meth) acrylate (C) include ethylene oxide-modified bisphenol A
Di (meth) acrylate, trimethylolethanetri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris (meth) acryloyloxyethyl isocyanurate, pentaerythritol tetra (meth) acrylate, Examples thereof include dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

The amount of the polyfunctional (meth) acrylate (C) used is 0 to 40 parts by weight, preferably 0 to 30 parts by weight, based on 100 parts by weight of the total of the components (A) to (C). is there. If the amount used exceeds 40 parts by weight, the stress due to curing shrinkage increases, and the adhesive strength tends to decrease.

The photopolymerization initiator (D) used in the present invention generates radical species upon irradiation with light to initiate polymerization, and may be appropriately selected from various conventionally known photopolymerization initiators. Specific examples thereof include 2-hydroxy-2-methyl-1-phenylpropan-1-one,
-Hydroxycyclohexylphenyl ketone, methylphenylglyoxylate, acetophenone, benzophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-methyl [4- (methylthio) phenyl] morpholino-1-propanone, benzyl, benzoin methyl ether, Benzoin ethyl ether, 2-chlorothioxanthone, isopropylthioxanthone, 2,4,6-
Trimethylbenzoyldiphenyl-phosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,
4,4-trimethylpentyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

The amount of the photopolymerization initiator (D) used is from (A) to
(C) 0.01 to 5 parts by weight based on a total of 100 parts by weight of the component.
Parts by weight. If the amount is less than 0.01 part by weight, the curability of the adhesive composition tends to be insufficient.
On the other hand, when this amount exceeds 5 parts by weight, the adhesive composition is apt to yellow.

The adhesive composition of the present invention may further contain additives such as a thermal oxidation stabilizer, an ultraviolet absorber, a bluing agent, an antifoaming agent, and a polymerization inhibitor, as long as the effects of the present invention are not impaired. It may be added. When the adherend is glass, a silane coupling agent copolymerizable with the components in the composition may be added to increase the adhesive strength.

The adhesive composition of the present invention can be polymerized and cured by light irradiation. As the light source,
For example, conventionally known light sources such as ultraviolet rays, X-rays, electron beams, and visible rays can be used without any particular limitation. For example, in the case of curing by irradiation of ultraviolet rays, a wavelength of 2000 to 80
It is preferable to use ultraviolet rays of 00 °, and as the light source, for example, a chemical lamp, a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, or the like may be used.

The adhesive composition of the present invention can be used for bonding various members. For example, a glass plate, a polycarbonate plate, a resin plate such as an acrylic plate, or the like can be used for bonding the same or different kinds of combinations. In particular,
Since the cured product of the adhesive composition of the present invention is colorless and transparent, it is suitable for bonding a transparent member such as an organic glass or an inorganic glass.

The optical member of the present invention is characterized in that the optical member is formed by laminating a sheet-like lens with the photocurable adhesive composition of the present invention. As a specific example of this optical member, by filling and curing between the sheet-shaped lenses with the adhesive composition of the present invention, for example, a front plate and a Fresnel lens are bonded, or a Fresnel lens and a lenticular lens are bonded. And the like.
The optical member of the present invention is colorless and transparent and has good adhesion without peeling or the like even in various environments.

[0034]

The present invention will be described in more detail with reference to the following examples.

[Synthesis Example 1: Synthesis of polyethylene glycol urethane methacrylate polymer (PPEG)] In a three-necked flask, polyethylene glycol 2000 (a reagent manufactured by Kishida Chemical Co., Ltd., Mw = 1800-2200) 51
0.0 parts by weight, 0.35 parts by weight of di-n-butyltin dilaurate as a catalyst and 0.30 parts by weight of p-methoxyphenol as a polymerization inhibitor were added, and the temperature was raised to 50 ° C. while stirring.

In addition, methylene-bis- (4-cyclohexyl isocyanate) (Sumitomo Bayer Urethane Co., Ltd.)
132.4 parts by weight of 60
The mixture was dropped over a period of minutes, and then the temperature was raised to 70 ° C., and stirring was continued for 2 hours. Subsequently, the temperature was lowered to 50 ° C., and 58.1 parts by weight of hydroxyethyl acrylate was added dropwise over 30 minutes. After the completion of the addition, the temperature was raised to 70 ° C., and stirring was continued for 3 hours to complete the reaction.

The polyethylene glycol urethane methacrylate polymer (PPEG) thus obtained has a weight average molecular weight (Mw) of 479 in terms of polystyrene.
00.

[Synthesis Example 2: Synthesis of polybutadiene urethane methacrylate polymer (PPB)] In a three-necked flask, polybutadiene polyol (Nisso PB G-3000, manufactured by Nippon Soda Co., Ltd., Mw = 300)
0) 173.9 parts by weight, di-n-dilaurate as catalyst
0.18 parts by weight of butyltin and 0.1 part by weight of p-methoxyphenol as a polymerization inhibitor were added, and the mixture was stirred at 50 ° C.
And then isophorone diisocyanate 22.2
A part by weight was added dropwise over 30 minutes, the temperature was raised to 70 ° C., and stirring was continued for 2 hours. Next, the temperature was lowered to 50 ° C., and 17.3 parts by weight of hydroxypropyl methacrylate was added dropwise over 30 minutes.
The reaction was completely terminated.

The weight average molecular weight (Mw) of the polybutadiene urethane methacrylate polymer (PPB) thus obtained was 32,000 in terms of polystyrene.

[Synthesis Example 3: Synthesis of Polycarbonate Urethane Methacrylate Polymer (PPC)] In a three-necked flask, polycarbonate diol (a reagent manufactured by Daicel Chemical Industries, Ltd., trade name PLACCEL CD-208,
(Mw = 800) 20.2 parts by weight, 0.15 parts by weight of di-n-butyltin dilaurate as a catalyst and 0.15 parts by weight of p-methoxyphenol as a polymerization inhibitor were stirred at room temperature, and then 2-methacryloyl was added. 77.5 parts by weight of oxyethyl isocyanate were added dropwise over 30 minutes. After completion of the dropwise addition, the temperature was raised to 40 ° C., and stirring was continued for 2 hours to complete the reaction.

The weight average molecular weight (Mw) of the polycarbonate urethane methacrylate polymer (PPC) thus obtained was Mw = 1110 in terms of polystyrene.
Met.

Example 1 The polyethylene glycol urethane methacrylate polymer obtained in Synthesis Example 1 (PP
EG) 30 parts by weight, hydroxyethyl methacrylate 2
0 parts by weight, 50 parts by weight of benzyl methacrylate, 0.5 parts by weight of γ-methacryloyloxypropyltrimethoxysilane as a copolymerizable silane coupling agent, and 2-hydroxy-2-methyl-1-phenylpropane as a photopolymerization initiator 1.0 part by weight of -1-one and 1.0 part by weight of 1-hydroxycyclohexylphenyl ketone were mixed,
A photocurable adhesive composition was obtained.

This adhesive composition was applied to a glass plate having a thickness of 3 mm so as to have an adhesion area of 25 square mm, and a polycarbonate resin (PC) plate having a thickness of 2 mm [GE
(Trade name, Lexan LS-II, manufactured by the Company) are superimposed so that the thickness of the adhesive composition becomes 200 μm, and the glass plate is irradiated with ultraviolet rays 3000 mJ / cm ² using a high-pressure mercury lamp to cure the adhesive. Was.

When a tensile shear test (head-speed 20 mm / min) was carried out on the obtained test piece at 20 ° C., the tensile shear strength was 23.3 MPa.

Examples 2 to 4 Using the polymer (PPB) obtained in Synthesis Example 2, the compounds shown in Table 1 were mixed to obtain a photocurable adhesive composition. Using these adhesive compositions, test pieces were prepared in the same manner as in Example 1, and a tensile shear test was performed.
6.9 MPa in Example 3, 5.9 MPa in Example 3, Example 4
Was 17.8 MPa.

Example 5 Using the polymer (PPEG) obtained in Synthesis Example 1, the compounds shown in Table 1 were mixed to obtain a photocurable adhesive composition. Using this adhesive composition, a test piece was prepared in the same manner as in Example 1, and a tensile shear test was performed. The tensile shear strength was 12.2 MPa.
a.

Example 6 Using the polymer (PPC) obtained in Synthesis Example 3, the compounds shown in Table 1 were mixed to obtain a photocurable adhesive composition. Using this adhesive composition,
A test piece was prepared in the same manner as in Example 1, and a tensile shear test was performed. As a result, the tensile shear strength was 9.6 MPa.

Example 7 The polycarbonate resin plate of Example 1 was replaced with polymethyl methacrylate (PM) having a thickness of 2 mm.
MA) A test piece was prepared in the same manner as in Example 1 except that a plate (Acrylite L, trade name, manufactured by Mitsubishi Rayon Co., Ltd.) was used, and a tensile shear was performed. The test was performed. Its tensile shear strength was 18.8 MPa.

Examples 8 to 15 Using the polymers obtained in Synthesis Examples 1 to 3, the compounds shown in Table 1 were mixed to obtain photocurable adhesive compositions. Using these adhesive compositions, test pieces were prepared in the same manner as in Example 1, and a tensile shear test was performed. Table 1 shows the results.

[Comparative Examples 1, 4, and 5] Photocurable adhesive compositions were prepared according to the compositions shown in Table 2, test pieces were prepared in the same manner as in Example 1, and tensile shear tests were performed. The tensile shear strength was as low as 0.4 MPa in Comparative Example 1, 0.1 MPa in Comparative Example 4, and 0.8 MPa in Comparative Example 5, indicating a brittle cured product.

[Comparative Examples 2 and 3] A photocurable adhesive composition was prepared according to the composition shown in Table 2, and a test piece was prepared in the same manner as in Example 1. The viscosity of the adhesive was too high. Application was difficult.

[Comparative Example 6] A photocurable adhesive composition was prepared according to the composition shown in Table 2, and a test piece was prepared in the same manner as in Example 1. The shear test could not be performed.

Comparative Example 7 A photocurable adhesive composition was prepared according to the composition shown in Table 2, a test piece was prepared in the same manner as in Example 1, and a tensile shear test was performed. The tensile shear strength was 16.1 MPa, but the cured product of the adhesive was visually discolored to yellow.

[0054]

[Table 1]

[0055]

[Table 2]

In the numerical units in the table, the composition part is "parts by weight", the tensile shear strength is "MPa", and the abbreviations in the table are as follows. PPEG: polyethylene glycol urethane methacrylate polymer obtained in Synthesis Example 1 Mw = 47900 PPB: polybutadiene urethane methacrylate polymer Mw obtained in Synthesis Example 2 = 32000 PPC: polycarbonate urethane methacrylate polymer Mw obtained in Synthesis Example 3 HEMA: hydroxyethyl methacrylate THFA: tetrahydrofurfuryl acrylate BzMA: benzyl methacrylate ABPE: ethylene oxide-modified bisphenol A
Diacrylate • DPHA: dipentaerythritol hexaacrylate • HMPP: 2-hydroxy-2-methyl-1-phenylpropan-1-one • HCCP: 1-hydroxycyclohexyl phenyl ketone • A174: γ-methacryloyloxypropyltrimethoxysilane

[0057]

As described in detail above, according to the present invention,
A light-curing adhesive which is a one-part curing type, is easy to handle, does not discharge a solvent or the like, cures in a short time, and has high adhesive strength, and an optical member using the same can be provided.

Continued on the front page F term (reference) 2H025 AB14 AB20 AC01 AC05 AC06 AD01 BC14 BC34 BC43 BC66 BC92 4J040 EF111 EF112 EF121 EF122 EF131 EF132 EF141 EF142 EF151 EF152 EF181 EF182 EF221 EF222 EF251 EF252 FA 161 FA EF FA 172 FA EF FA FA171 FA172 FA281 FA282 FA291 FA292 GA05 HB19 HB20 HB31 HC26 HD19 HD23 JB08 KA13 KA24 LA01 MA05 MA10 MB03 NA18

Claims (4)

[Claims] 1. A urethane polymer having two or more (meth) acryloyloxy groups in one molecule, (A) 5 to 70 parts by weight, monofunctional (meth) acrylate (B) 30 to 95 parts by weight, polyfunctional (meth) ) 0-40 parts by weight of acrylate (C) and 0.01-5 parts by weight of photopolymerization initiator (D) [(A)
(A total of 100 parts by weight of the components (B) and (C)). 2. The photocurable adhesive composition according to claim 1, wherein the urethane polymer (A) has a weight average molecular weight of 1500 or more. 3. The monofunctional (meth) acrylate (B) is
The photocurable adhesive composition according to claim 1, comprising at least a (meth) acrylate having a hydroxyl group. 4. An optical member obtained by laminating a sheet lens with the photocurable adhesive composition according to claim 1.