JP6283479B2 - Photocurable resin composition and sealing material - Google Patents

Description

  The present invention relates to a photocurable resin composition and a sealing material.

In recent years, various photocurable resins have been developed for sealing materials and adhesives.
For example, for the purpose of obtaining a cured product excellent in low moisture permeability, adhesion and setability, (A) a reactive polymer having a (meth) acryloyl group at the terminal, and (B) a (meth) acrylic acid ester monomer , (C) a photo radical polymerization initiator, and (D) a photocurable sealing material composition containing a predetermined amount of an inorganic filler and / or an organic thickener is disclosed (for example, patents). Reference 1).
In addition, in order to obtain a material suitable for a sealing material having a high water vapor barrier property, excellent heat resistance, and appropriate hardness as a rubber elastic material, (A) a conjugated diene monomer or conjugated with a dilithium initiator A step of polymerizing a diene monomer and an aromatic vinyl monomer to produce a (co) polymer having a predetermined molecular weight and molecular weight distribution; and (B) the (co) polymer and an alkylene oxide. Reacting to produce a (co) polymer polyol; (C) hydrogenating the (co) polymer polyol to produce a hydrogenated (co) polymer polyol; (D) It has been reported that a photocurable liquid resin is produced by a method comprising a step of reacting a hydrogenated (co) polymer polyol and a photocurable unsaturated hydrocarbon group-containing compound (for example, Patent Document 2). reference).

JP 2006-298964 A JP 2007-145949 A

  The cured product of the photocurable sealing material composition described in Patent Document 1 and the cured product obtained by the method described in Patent Document 2 have insufficient flexibility. Further, depending on the type of photopolymerization initiator used for preparing the composition, the water vapor permeability (moisture permeability) of the cured product may be increased, and the adhesiveness may be decreased. Therefore, there was room for further improvement.

An object of the present invention is to achieve the following object.
That is, the present invention provides a photocurable resin composition that can provide a cured product having low moisture permeability, high adhesion, and excellent flexibility, and low moisture permeability, high adhesion, and excellent flexibility. It aims at providing the sealing material which has property.

In the present invention, a photocurable resin composition is formed by connecting an ester group and a terminal carboxy group with an alkylene group having a small number of carbon atoms together with a photocurable resin having a structural unit derived from a diene compound and a cyclic photocurable monomer. It was found and completed that a cured product having low moisture permeability, high adhesion, and high flexibility can be obtained by containing a photocurable monomer having a molecular chain.
Specific means for solving the above-described problems are as follows.

[1] (A) a photocurable resin having a structural unit derived from a diene compound and having (meth) acryloyl groups at both ends;
(B) a photocurable monomer having a non-conjugated cyclic hydrocarbon group and a (meth) acryloyl group;
(C) a photocurable monomer represented by the following general formula (1);
(D) A photocurable resin composition comprising a photopolymerization initiator.

[In General Formula (1), R represents a hydrogen atom or a methyl group, and X and Y each independently represent an acyclic hydrocarbon group having 2 to 4 carbon atoms. ]
[2] The photocurable resin composition according to [1], wherein Y is a linear hydrocarbon group.
[3] The photocurable resin composition according to [1] or [2], wherein the ring of the non-conjugated cyclic hydrocarbon group is a bridged ring.
[4] The photocurable resin composition according to any one of [1] to [3], wherein the structural unit derived from the diene compound is a structural unit derived from at least one of butadiene and isoprene.
[5] The photocurable resin composition according to any one of [1] to [4], wherein the structural unit derived from the diene compound is hydrogenated.
[6] The content of the (C) photocurable monomer is 0.1 to 15 parts by mass with respect to 100 parts by mass in total of the (A) photocurable resin and the (B) photocurable monomer. The photocurable resin composition according to any one of [1] to [5], which is part by mass.
[7] The content of the (B) photocurable monomer is 10 parts by mass to 50 parts by mass with respect to 100 parts by mass in total of the (A) photocurable resin and the (B) photocurable monomer. The photocurable resin composition according to any one of [1] to [6].
[8] A sealing material obtained by irradiating the photocurable resin composition according to any one of [1] to [7] with light.

  ADVANTAGE OF THE INVENTION According to this invention, the photocurable resin composition from which the hardened | cured material which has low moisture permeability, high adhesiveness, and high flexibility can be obtained can be provided. Furthermore, according to the present invention, it is possible to provide a sealing material that has low moisture permeability, high adhesion, and high flexibility, and also has excellent compression fracture strength.

It is the figure which showed typically the measuring method of the compression fracture strength of an Example and a comparative example.

<Photocurable resin composition>
The photocurable resin composition of the present invention comprises (A) a photocurable resin having a structural unit derived from a diene compound and having (meth) acryloyl groups at both ends, and (B) a non-conjugated cyclic hydrocarbon group. And a photocurable monomer having a (meth) acryloyl group, (C) a photocurable monomer represented by the general formula (1), and (D) a photopolymerization initiator.
Hereinafter, (A) a photocurable resin having a structural unit derived from a diene compound and having (meth) acryloyl groups at both ends is also referred to as a “diene polymer”. (B) A photocurable monomer having a non-conjugated cyclic hydrocarbon group and a (meth) acryloyl group is also referred to as a “cyclic monomer”. (C) The photocurable monomer represented by the general formula (1) is also referred to as “specific monomer”.
Moreover, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.
Hereinafter, the components (A) to (D) included in the photocurable resin composition of the present invention and various components that can be included in the photocurable resin composition of the present invention will be described in detail.

[(A) Photocurable resin having a structural unit derived from a diene compound and having (meth) acryloyl groups at both ends (diene polymer)]
The photocurable resin composition of the present invention includes (A) a photocurable resin (diene polymer) having a structural unit derived from a diene compound and having (meth) acryloyl groups at both ends.
The hardened | cured material of the photocurable resin composition of this invention has a softness | flexibility because the photocurable resin composition of this invention contains the diene polymer which is (A) component.
The diene-based polymer is not particularly limited as long as it has a structural unit derived from a diene compound in the molecule and has (meth) acryloyl groups at both ends of the molecular chain. Or may have other structural units. High adhesiveness can be obtained by having a (meth) acryloyl group at the “both ends” of the molecular chain, but a photocurable resin having a (meth) acryloyl group at the “one end” of the molecular chain in the component (A) In the component (A), the content is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less.

[Structural unit derived from diene compound]
The “diene compound-derived structural unit” refers to a structural unit formed by addition polymerization of a compound having two double bonds in the molecule, that is, a so-called diene compound. Further, the structural unit derived from the diene compound may be hydrogenated (also simply referred to as hydrogenation).
The diene compound constituting the structural unit derived from the diene compound is not particularly limited, and isoprene, 1,3-butadiene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1, 3-hexadiene etc. are mentioned. The structural unit derived from a diene compound may be derived from only one of the above diene compounds, or may be derived from two or more diene compounds. Among these, from the viewpoint of easily obtaining the flexibility of the cured product of the photocurable resin composition, the diene compound is preferably at least one of butadiene and isoprene, and more preferably 1,3-butadiene.
When the structural unit derived from the diene compound is hydrogenated, the hydrogenation rate is preferably 70 mol% or more from the viewpoint of weather resistance and the like. The larger the hydrogenation rate, the better. Specifically, it is more preferably 80 mol% or more, further preferably 90 mol% or more, and particularly preferably 95 mol% or more. What is necessary is just to calculate the hydrogenation rate of the structural unit derived from a diene compound using a nuclear magnetic resonance spectrum (< ¹ > H-NMR spectrum).

  When the diene compound is 1,3-butadiene, examples of the structural unit derived from 1,3-butadiene include a structural unit represented by the following formula (i) or formula (ii).

[M1 and n1 in formula (i) and m2 and n2 in formula (ii) are the average number of repeating units, each independently representing 0 or more, and 1 ≦ m1 + n1, ≦ m2 + n2. ]

The structure represented by m1 of formula (i) or m2 of formula (ii) represents a 1,2-addition unit of butadiene, and the structure represented by n1 of formula (i) or n2 of formula (ii) is butadiene. Represents a 1,4-addition unit.
Formula (i) represents that the structural unit derived from butadiene is not hydrogenated (non-hydrogenated state), and Formula (ii) represents that the structural unit derived from butadiene is hydrogenated (hydrogenated) State). In formula (ii), both the 1,2-addition unit and the 1,4-addition unit are hydrogenated. However, from the viewpoint of increasing the compression fracture strength of the cured product, the structural unit derived from the diene compound is preferably hydrogenated. When the diene compound is 1,3-butadiene, the diene polymer is It preferably has formula (ii).
Further, m1: n1 and m2: n2 are each preferably 15:85 to 95: 5, more preferably 60:40 to 95: 5, from the viewpoint of moisture permeability and reworkability. .

The diene polymer has various linking groups such as a divalent hydrocarbon group, an ester bond, an amide bond, an ER bond, and a urethane bond between the structural unit derived from the diene compound and the (meth) acryloyl group. It may be. Moreover, you may have structural units other than the structural unit derived from a diene compound.
From the viewpoint of ease of synthesis when the diene polymer is obtained by synthesis, the diene polymer has a urethane bond between the structural unit derived from the diene compound and the (meth) acryloyl group. Is preferred.

The diene polymer may be synthesized or a commercially available product may be used.
When synthesizing a diene polymer, for example, it can be produced as follows.
For example, as a diene compound, a diene polymer having both ends hydroxyl groups (for example, polybutadiene; see Polymerization Production Example 1 of JP-A-2007-145949) is reacted with a lower ester of acrylic acid (such as methyl acrylate). The both ends may be acrylated. At this time, the diene polymer having both hydroxyl groups at the ends may be a non-hydrogenated diene polymer or a hydrogenated hydrogenated diene polymer. However, from the viewpoint of lowering the moisture permeability of the cured product, a hydrogenated diene polymer is preferable.
Moreover, the acrylic acid ester monomer (2-hydroxyethyl acrylate etc.) which has a hydroxyl group may be made to react with the diene polymer whose both terminal is an isocyanate group, and both terminal may be acrylated.
When the diene polymer is obtained as a commercial product, for example, CN9014 manufactured by Sartomer Japan, UC-102 manufactured by Kuraray Co., Ltd., SPBDA-S30 manufactured by Osaka Organic Chemical Industry Co., Ltd., and Osaka Organic Chemical Co., Ltd. BAC-45 manufactured by Kogyo Co., Ltd. may be used. SPBDA-S30 has a structural unit derived from hydrogenated butadiene, and UC-102 and BAC-45 have a structural unit derived from non-hydrogenated butadiene.

The weight average molecular weight of the diene polymer is preferably 1,000 to 100,000, and more preferably 2,000 to 50,000. When the weight average molecular weight of the diene polymer is 1,000 to 100,000, the hardness of the cured product can be suppressed and the flexibility is excellent.
The content of the diene polymer in the photocurable resin composition of the present invention is such that the diene polymer [(A) photocurable resin] and the cyclic monomer [( B) 50 parts by weight to 90 parts by weight, more preferably 54 parts by weight to 85 parts by weight, and more preferably 60 parts by weight to 85 parts by weight with respect to 100 parts by weight as a total. More preferably.

[(B) Photocurable monomer having non-conjugated cyclic hydrocarbon group and (meth) acryloyl group (cyclic monomer)]
The photocurable resin composition of the present invention includes (B) a photocurable monomer (cyclic monomer) having a non-conjugated cyclic hydrocarbon group and a (meth) acryloyl group.
When the photocurable resin composition of the present invention contains the cyclic monomer as the component (B), the moisture permeability of the cured product of the photocurable resin composition of the present invention is lowered. That is, the water vapor barrier property is enhanced.
The cyclic monomer is not particularly limited as long as it has a non-conjugated cyclic hydrocarbon group and a (meth) acryloyl group.

Examples of the non-conjugated cyclic hydrocarbon group include a cycloalkyl group (saturated alicyclic group) and a non-conjugated cycloalkenyl group (unsaturated alicyclic group). The number of carbon atoms of the non-conjugated cyclic hydrocarbon group is preferably 5 to 20, more preferably 6 to 15, and still more preferably 7 to 10.
Specific examples of the cycloalkyl group include a cyclohexyl group, a cyclopentyl group, a bornyl group, an isobornyl group, a dicyclopentanyl group, an adamantyl group, and the like.
Specific examples of the non-conjugated cycloalkenyl group include a cyclobutenyl group, a cyclohexenyl group, a 1,5-cyclooctadienyl group, a dicyclopentenyl group, and a norbornenyl group.
The non-conjugated cyclic hydrocarbon group preferably has a bulky molecular structure from the viewpoint of moisture permeability of the cured product of the photocurable resin composition. That is, the ring of the non-conjugated cyclic hydrocarbon group is preferably a bridged ring such as a bicyclo structure or a tricyclo structure. Among the above examples, bornyl group, isobornyl group, dicyclopentanyl group, adamantyl group, dicyclopentenyl group, and norbornenyl group are preferable, and dicyclopentanyl group, dicyclopentenyl group, and isobornyl group are more preferable. .

Specific examples of the cyclic monomer include, for example, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dimethylol dicyclopentane di ( Examples include meth) acrylate and isobornyl (meth) acrylate.
Among these, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate and isobornyl (meth) acrylate are preferable, and dicyclopentanyl acrylate, dicyclopentenyl acrylate and isobornyl acrylate are more preferable.

A cyclic monomer may be used individually by 1 type, and 2 or more types may be mixed and used for it.
In addition, the content of the cyclic monomer in the photocurable resin composition of the present invention is such that the diene polymer [(A) photocurable resin] and the cyclic monomer [( It is preferable that it is 10 mass parts-50 mass parts with respect to a total of 100 mass parts with B) photocurable monomer], It is more preferable that they are 15 mass parts-46 mass parts, 15 mass parts-30 mass parts More preferably.

[(C) Photocurable monomer represented by general formula (1) (specific monomer)]
The photocurable resin composition of this invention contains the photocurable monomer (specific monomer) represented by (C) general formula (1).

[In General Formula (1), R represents a hydrogen atom or a methyl group, and X and Y each independently represent an acyclic hydrocarbon group having 2 to 4 carbon atoms. ]

  When the photocurable resin composition of the present invention contains the specific monomer that is the component (C) together with the component (B), the cured product of the photocurable resin composition of the present invention as compared with the case where the specific monomer is not included. Increase adhesion and flexibility.

In general formula (1), R represents a hydrogen atom or a methyl group.
X and Y in the general formula (1) each independently represents an acyclic hydrocarbon group having 2 to 4 carbon atoms. Since X and Y are acyclic hydrocarbon groups having 2 to 4 carbon atoms, the three-dimensional molecular movement of the cured product of the photocurable resin composition is facilitated, and the flexibility of the cured product is increased. Moreover, adhesiveness improves. Moreover, it is difficult to synthesize a compound in which X and Y have 1 carbon atom or a compound having more than 4 carbon atoms.
Examples of the acyclic hydrocarbon group having 2 to 4 carbon atoms include an alkylene group, an alkenylene group, and an alkynylene group, and the molecular structure may be linear or branched.
Examples of the alkylene group include an ethylene group (ethanediyl group), a propylene group (propanediyl group), and a butylene group (butanediyl group).
Examples of the alkenylene group include a vinylene group, a propenylene group, and a butenylene group.
Examples of alkynylene groups include ethynylene groups and propynylene groups.
Among these, the acyclic hydrocarbon group represented by X and Y is a linear alkylene group, that is, a 1,2-ethanediyl group (—CH ₂ CH ₂ —), a 1,3-propanediyl group ( _{-CH 2 CH 2 CH 2 -)} , and 1,4-butanediyl group _{(-CH 2 CH 2 CH 2 CH} 2 -) is preferred. Furthermore, a 1,2-ethanediyl group and a 1,3-propanediyl group are more preferable, and a 1,2-ethanediyl group is particularly preferable.

The content of the specific monomer [(C) photocurable monomer] in the photocurable resin composition of the present invention is a diene polymer [from the viewpoint of adhesiveness and moisture permeability of the cured product of the photocurable resin composition. It is preferable that it is 0.1-15 mass parts with respect to a total of 100 mass parts of (A) photocurable resin] and a cyclic monomer [(B) photocurable monomer]. Adhesiveness of hardened | cured material can be improved more because content of the specific monomer with respect to a total of 100 mass parts of a diene polymer and a cyclic monomer is 0.1 mass part or more, and it is 15 mass parts or less. Thus, the flexibility of the cured product can be increased and the moisture permeability can be further reduced.
The content of the specific monomer with respect to a total of 100 parts by mass of the diene polymer and the cyclic monomer is more preferably 0.3 parts by mass to 15 parts by mass, and then preferably 0.5 parts by mass to 15 parts by mass, and 0.5 parts by mass. Parts to 13.5 parts by weight are then preferred, 0.5 parts to 8 parts by weight are then preferred, 0.5 parts to 4 parts by weight are preferred, and 1 part to 2 parts by weight are particularly preferred.

[(D) Photopolymerization initiator]
The photocurable resin composition of the present invention contains (D) a photopolymerization initiator.
The photopolymerization initiator as component (D) is one in which the curing reaction of components (A), (B), and (C) proceeds and a cured product of the photocurable resin composition of the present invention can be obtained. If there is, it will not restrict | limit in particular, A well-known thing can be used.
Examples of the photopolymerization initiator include, as intramolecular cleavage types, benzoin derivatives, benzyl ketals [for example, manufactured by BASF Japan Ltd., trade name: Irgacure 651], α-hydroxyacetophenones [for example, BASF Japan ( Product name: Darocur 1173, Irgacure 184, Irgacure 127], α-aminoacetophenones [for example, product name: Irgacure 907, Irgacure 369], α-aminoacetophenones and thioxanthones (For example, isopropylthioxanthone, diethylthioxanthone), acylphosphine oxides [for example, product name: Irgacure 819] manufactured by BASF Japan Ltd., and the like. Emissions of the combination, and the like combination of thioxanthones and amines. Further, an intramolecular cleavage type and a hydrogen abstraction type may be used in combination. Of these, α-hydroxyacetophenone and benzophenones are preferable.
Examples of the photopolymerization initiator include the photoradical polymerization initiator described in paragraph [0036] of JP-A-2006-298964 in addition to the above.

  In addition, the content of the photopolymerization initiator in the photocurable resin composition of the present invention is selected from the diene polymer [(A) photocurable resin] and cyclic from the viewpoint of curability of the photocurable resin composition. It is preferably 0.1 parts by mass to 5 parts by mass, more preferably 0.5 parts by mass to 5 parts by mass with respect to 100 parts by mass in total with the monomer [(B) photocurable monomer], More preferably, it is 0.8-3 mass parts.

[(E) Additive]
The photocurable resin composition of the present invention may further contain various (E) additives.
(E) There is no restriction | limiting in particular as an additive, For example, coloring agents, such as a stabilizer, a photosensitizer, an inorganic filler, a thickener, tackifying resin, titanium black, 1, 4- cyclohexylcarbodiimide, N , N′-ethylcarbodiimide and other carbodiimide compounds, polythiol and the like.
Examples of the stabilizer include those described in paragraph [0041] of JP-A-2006-298964. Moreover, about a photosensitizer, a thickener, and tackifier resin, the photosensitizer, thickener, and tackifier resin of Paragraph [0033] and [0034] of Unexamined-Japanese-Patent No. 2013-028861 are shown. Is mentioned.

The manufacturing method of the photocurable resin composition of this invention is not specifically limited, A well-known method is applicable. For example, (A), (B), (C), and (D) components, and (E) an additive capable of adjusting the temperature of the additive as required, for example, a single screw extruder, twin screw extruder, etc. It can be manufactured by kneading using a machine, a planetary mixer, a twin screw mixer, a high shear mixer and the like.
By irradiating the photocurable resin composition thus obtained with light, the photocurable resin composition can be cured to obtain a cured product.

The light beam that can be used for curing the photocurable resin composition of the present invention is specifically an active energy ray, and examples thereof include a particle beam, an electromagnetic wave, and a combination thereof.
Examples of the particle beam include an electron beam (EB) and an α ray. Examples of the electromagnetic wave include ultraviolet (UV), visible light, infrared light, γ-ray, and X-ray. Among these, it is preferable to use ultraviolet rays as active energy rays.
Examples of the ultraviolet light source include a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, and a microwave excimer lamp. The active energy ray is preferably irradiated in an inert gas atmosphere such as nitrogen gas or carbon dioxide gas or an atmosphere in which the oxygen concentration is lowered, but can be sufficiently cured even in a normal air atmosphere. The irradiation temperature of the active energy ray is usually preferably 10 ° C to 200 ° C, and the irradiation time is usually preferably 10 seconds to 60 minutes. The integrated light amount of the active energy ray is usually preferably 1,000 mJ / cm ^{2 to} 20,000 mJ / cm ² .

<Seal material>
The sealing material of the present invention is obtained by irradiating the photocurable resin composition of the present invention with light.
For example, what is necessary is just to manufacture a sealing material as hardened | cured material by apply | coating the photocurable resin composition of this invention to a to-be-adhered body, forming the application layer of a desired shape, and irradiating with a light beam.
As the adherend, for example, one made of a hard resin can be used, but a metal one is preferable from the viewpoint of workability. There are no particular restrictions on the metal, for example, cold-rolled steel sheet, galvanized steel sheet, aluminum / zinc alloy plated steel sheet, stainless steel sheet, aluminum plate, aluminum alloy plate, magnesium plate, magnesium alloy plate, etc. Use it. Moreover, you may use what injection-molded magnesium. From the viewpoint of corrosion resistance, a metal subjected to electroless nickel plating is preferable.

Application | coating to the to-be-adhered body of a photocurable resin composition should just be performed by arbitrary methods using the coating liquid which adjusted the temperature of the photocurable resin composition as needed, and adjusted it to fixed viscosity.
Examples of the method include gravure coating, roll coating, spin coating, reverse coating, bar coating, screen coating, blade coating, air knife coating, dipping, and dispensing. In this way, after applying the coating liquid and forming the coating layer, the coating layer may be cured by irradiating light to form a sealing material.

The sealing material of the present invention is useful as a gasket for an electronic product such as a hard disk drive (HDD), a seal for an ink tank, a liquid crystal seal, and the like.
The sealing material has a cross-sectional aspect ratio (width: height) of the coating layer of the photocurable resin composition of 1: 0.5 to 1: 2 from the viewpoint of good sealing performance and efficient use of the space in the HDD. It is preferable to apply the photocurable resin composition to the adherend so as to be 0.0. The cross-sectional aspect ratio (width: height) of the coating layer is more preferably 1: 0.8 to 1: 2.0.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited at all by these examples.
The cured products of the photocurable resin compositions prepared in Examples , Reference Examples, and Comparative Examples described later were evaluated by the following methods, and the evaluation results are shown in Table 1.
All cured products of the photocurable resin composition were coated at 25 ° C. in an air atmosphere with a photocurable resin composition on a glass substrate to form a sheet and then irradiated with UV under the following UV irradiation conditions. Obtained.
[UV irradiation conditions]
・ Irradiation device: UV irradiation machine SE-UV1501BA-LT manufactured by Sen Engineering Co., Ltd.
・ Irradiation source: Metal halide lamp ・ Irradiation temperature: 25 ℃
・ Irradiation time: 60 seconds ・ Light wavelength: range from 320 nm to 390 nm ・ Integrated light quantity: 2,000 mJ / cm ²
・ Irradiation condition: Under air atmosphere

1. Method for Measuring Hardness (Shore A) After the photocurable resin composition is formed into a sheet form and UV-irradiated into a cured product (sealing material) in Examples , Reference Examples or Comparative Examples, the thickness becomes about 6 mm. I stacked the sheets until. About the obtained laminated body, hardness was measured based on JISK6253 (type A durometer). For the measured value, the load holding time was 4 seconds.
The target value is 65 or less.

2. Measurement method of moisture permeability The photocurable resin composition obtained in the example , reference example or comparative example was formed into a sheet and irradiated with UV to obtain a cured product (sealing material), thereby obtaining a sheet having a thickness of 1 mm. . Using this as a specimen, the moisture permeability of the specimen was measured under the conditions of 50 ° C. and 90% relative humidity in accordance with JIS Z0208 using a moisture permeability cup of Method A described in JIS L1099. It shows that it is excellent in the permeation | transmission resistance of water vapor, so that the value of moisture permeability is small.
The target value is 10 g / m ² · 24 hr or less.

3. Adhesive evaluation method The photo-curable resin composition obtained in Examples , Reference Examples or Comparative Examples is made into a sheet and irradiated with UV to form a cured product (sealing material), and a sheet having a thickness of 0.86 mm is obtained. Obtained. Next, a metal plate (25 × 60 × 0.8 mm) obtained by electroless nickel plating having a thickness of 5 μm on an A5052P aluminum alloy specified by JIS H4000 was prepared.
Based on JIS K6256, the adhesive strength [N / mm] between the metal plate and the obtained sheet was determined.
The target value is 1 N / mm or more.

4). Method of measuring compressive fracture strength The photocurable resin compositions obtained in Examples , Reference Examples or Comparative Examples were poured into a mold having three molds having a width of 1 mm, a depth of 10 mm, and a depth of 0.72 mm. A cured product was obtained under the irradiation conditions described above. Next, the cured product was placed on a step-shaped jig having different heights, and the cured product was sandwiched between the jig and a plate to compress the cured product. Specifically, it was performed as follows.
FIG. 1 shows a state in which three cured products 2 are placed on a stepped jig 4 having different heights. The jig 4 has steps at both ends that are the same, and has a step between the steps that is lower than the height of the end step and a step that is even lower. Spacers 6 were placed on both stages of the jig 4 respectively. Next, the plate 8 was placed on the cured product 2, and the plate 8 was pressed against the cured product 2 until the plate 8 was in contact with the spacer 6. The cured product 2 is compressed to a thickness of “the depth of each recess of the jig 4” + “the thickness of the spacer 6” or “the thickness of the spacer 6” for each step. For example, the cured product placed on the step where the gap between the laminate of the plate 8, the spacer 6, and the jig 4 is 0.36 mm in height has a compression rate of 50% (100 × 0.36 mm / 0). 72 mm). The cured product 2 was allowed to stand at 80 ° C. for 20 hours while being sandwiched between the plate 8 and the jig 4. Then, the damage state of the three hardened | cured material 2 pinched | interposed with each compression rate was observed visually.
By this method, the compression fracture state of multiple types of cured products with different compression ratios is examined, and among the observed cured products, the compression rate of the cured product with the largest compression rate is the compression rate of the cured product. The breaking strength [%] was used. For example, the compression fracture strength of 50% means that the limit of not compressing the cured product and compressing it at 80 ° C. for 20 hours was a condition with a compression rate of 50%.
The target value is 50% or more.

<Creation of a photocurable resin composition>
Examples 1 and 2, Reference Examples 1 to 6 and Comparative Examples 1 to 12
Each component of (A), (B), (C), and (D) shown in Table 1 is mixed in the composition shown in Table 1, and a photocurable resin composition of an example , a reference example, or a comparative example. I made a thing.
Details of each component shown in Table 1 are shown below.

(A) Polymer A
Polymer A-1: A polymer synthesized from three raw materials of KRASOL HLBH-3000 manufactured by Cray Valley, isophorone diisocyanate, and 2-hydroxyethyl acrylate (having a structural unit derived from a hydrogenated diene compound).
・ Polymer A-2: UC-102 manufactured by Kuraray Co., Ltd.
(Contains structural units derived from non-hydrogenated butadiene.)
・ Polymer A-3: Nippon Synthetic Chemical Industry Co., Ltd., Purple light UV3700B
(Comparative polymer, UV curable urethane acrylate resin)
(B) Cyclic monomer B
・ Cyclic monomer B-1 manufactured by Hitachi Chemical Co., Ltd., FANCLIL FA-511AS
・ Cyclic monomer B-2: manufactured by Hitachi Chemical Co., Ltd., FANCLIL FA-512AS
Cyclic monomer B-3: Osaka Organic Chemical Industry Co., Ltd., IBXA
The chemical structures of cyclic monomers B-1 to B-3 are as follows.

(C) Monomer C
(Specific monomer)
Monomer C-1: Shin-Nakamura Chemical Co., Ltd., A-SA
(Comparative monomer)
・ Monomer C-2 ... manufactured by Kojin Film & Chemicals Co., Ltd., ACMO
Monomer C-3: Kojin Film & Chemicals, DMAA
・ Monomer C-4: NIPAM, manufactured by Kojin Film & Chemicals Co., Ltd.
Monomer C-5: Aronix M-140 manufactured by Toa Gosei Co., Ltd.
Monomer C-6: Osaka Organic Chemical Industry Co., Ltd., Viscoat # 2100
Monomer C-1 to monomer C-6 have the structures shown below.
(D) Photopolymerization initiator, BASF Japan K.K., Irgacure 184

In Table 1, the “remarks” column shows the characteristics of the components (A) to (D).
In the component (A), “diene-based” means that the polymer A-1 and the polymer A-2 have a structural unit derived from a diene compound. “Non-diene-based” means having no structural unit derived from the diene compound of polymer A-3.
“Saturated alicyclic ring” and “unsaturated alicyclic ring” in component (B) represent the ring structure of the non-conjugated cyclic hydrocarbon group possessed by each cyclic monomer.
In the component (C), “Y is —C ₂ H ₄ —”, “COOH and —COO—not contained”, “COOH not contained”, and “Y is a benzene ring” are represented by “—OCO of the general formula (1)”. -Y-COOH "part state.

As shown in Table 1, the cured products of Comparative Examples 1 to 3 and Comparative Example 9 that do not contain the specific monomer as the component (C) show low moisture permeability, but have low adhesiveness or flexibility. Was insufficient. Further, in place of the component (C), a monomer that is acyclic but does not have a carboxy group or an ester group (Comparative Examples 4 to 7), or a monomer in which Y in the general formula (1) is an aromatic ring When (Comparative Example 8) was included, the cured product could not be made flexible, and the moisture permeability increased or the adhesiveness decreased. As shown in Comparative Examples 10 to 12, even if the specific monomer was included as the component (C), the moisture permeability could not be reduced unless the diene polymer or the cyclic monomer was included.
On the other hand, the photocurable compositions of Examples 1 and 2 and Reference Examples 1 to 6 all had low hardness (flexibility), low moisture permeability, and high adhesion. Moreover, even if there was little content of a specific monomer from Example 1, 2 and Reference Example 4 , the hardened | cured material was flexible and showed the low water vapor transmission rate. Further, from the comparison between Reference Example 3 and Example 1 , it can be seen that if the amount of the specific monomer is increased and the amount of the cyclic monomer is decreased, the adhesiveness can be improved without deteriorating the flexibility and low moisture permeability. It was. When the component (A) in which the structural unit derived from the diene compound is hydrogenated ( Reference Example 5 ), the compression is further performed than when the non-hydrogenated component (A) is used ( Reference Example 6 ). The breaking strength was increased.

  The cured product obtained by irradiating the photocurable resin composition of the present invention with light has low moisture permeability, high adhesiveness, and excellent flexibility. Moreover, since the sealing material of the present invention is molded by irradiating the photocurable resin composition of the present invention with light, it has low moisture permeability, high adhesion, and high flexibility, and further has a compressive fracture strength. Also excellent. Therefore, the sealing material of this invention is excellent in the airtightness with respect to water vapor | steam, and the adhesiveness with the member adjacent to a sealing material.

  The sealing material of the present invention is particularly useful as a sealing material (sealing material) for electronic products. More specifically, sealing materials for electronic displays such as hard disk drive (HDD) gaskets, organic electroluminescence elements and inorganic electroluminescence elements, and electronic devices such as mobile phones, digital video cameras, and PDAs using LEDs. It is useful as a sealing material for light-emitting elements such as backlights, display units such as large displays and road indicators, and general lighting.

2 Cured material 4 Jig 6 Spacer 8 Plate

Claims (7)

(A) a photocurable resin having a structural unit derived from a diene compound and having (meth) acryloyl groups at both ends;
(B) a photocurable monomer having a non-conjugated cyclic hydrocarbon group and a (meth) acryloyl group;
(C) a photocurable monomer represented by the following general formula (1);
(D) with a photopolymerization initiator
Consists of
The content of the (C) photocurable monomer is 0.5 to 4 parts by mass with respect to a total of 100 parts by mass of the (A) photocurable resin and the (B) photocurable monomer. A certain photocurable resin composition.

[In General Formula (1), R represents a hydrogen atom or a methyl group, and X and Y each independently represent an acyclic hydrocarbon group having 2 to 4 carbon atoms. ]   The photocurable resin composition according to claim 1, wherein Y is a linear hydrocarbon group.   The photocurable resin composition according to claim 1 or 2, wherein the ring of the non-conjugated cyclic hydrocarbon group is a bridged ring.   The photocurable resin composition according to claim 1, wherein the structural unit derived from the diene compound is a structural unit derived from at least one of butadiene and isoprene.   The photocurable resin composition in any one of Claims 1-4 in which the structural unit derived from the said diene compound is hydrogenated. The content of the (B) photocurable monomer is 10 to 50 parts by mass with respect to a total of 100 parts by mass of the (A) photocurable resin and the (B) photocurable monomer. The photocurable resin composition in any one of Claims 1-5 . The sealing material formed by light-irradiating the photocurable resin composition in any one of Claims 1-6 .