JP5180051B2 - Resin composition for sealing material - Google Patents

Description

  The present invention is excellent in low moisture permeability, adhesion, transparency, weather resistance, solvent resistance and chemical resistance, for example, a resin composition for sealing materials suitable for sealing materials (hereinafter simply referred to as “resin composition”). It may be said that).

  In recent years, with the progress of advanced information society, various display electronic devices such as organic EL display devices, liquid crystal display devices and electrophoretic display devices, organic EL lighting devices, optical devices such as optical elements, optical waveguides, thin film silicon solar cells Many functional devices such as organic thin-film solar cells and solar cells such as dye-sensitized solar cells have been proposed. For these functional devices, a sealing material or a sealing material is usually used, but an epoxy resin or an acrylic resin has been conventionally used (for example, see Patent Documents 1, 2, and 3).

  As mentioned above, various functional devices use sealing materials and sealing materials in order to prevent the adverse effects of moisture and oxygen in the atmosphere, but they are insufficient in terms of their moisture permeability and various gas barrier performances. In order to improve the lifetime of the functional device, there is a demand for a sealing material (sealing material) having transparency and low gas barrier performance.

  On the other hand, a liquid crystal injection method called an ODF (One Drop Filling) method has recently been proposed for a liquid crystal display device in which liquid crystal is sealed (see Patent Document 4). In this ODF method, the sealing material comes into contact with the encapsulated liquid crystal in an uncured state, and this causes a liquid crystal panel misalignment (non-uniformity of the liquid crystal display) when the sealing material melts into the liquid crystal. Therefore, the sealing material is required to be non-staining to liquid crystals.

Furthermore, in dye-sensitized solar cells that enclose liquid electrolytes (including quasi-solid electrolytes such as gel electrolytes) in which iodine is dissolved in an organic solvent such as acetonitrile, the main seal and end seals are sealed. In addition to low moisture permeability, adhesiveness, transparency, and weather resistance, the part is required to have electrolyte solution resistance (see Patent Document 5).
JP-A-2005-320404 JP 2008-59945 A JP 2007-324259 A JP 2006-323033 A JP 2008-140759 A

  As described above, the sealing material (sealing material), which is the sealing material for functional devices, which has been actively developed in recent years, has low moisture permeability, adhesiveness, and transparency as described above. In addition to the properties and weather resistance, there is a strong demand for the development of a product having excellent characteristics with respect to solvent resistance and chemical resistance.

  The present invention has been made in view of such circumstances, and is suitable for a sealing material (sealing material) excellent in solvent resistance and chemical resistance in addition to low moisture permeability, adhesiveness, transparency, and weather resistance. It is an object of the present invention to provide a resin composition.

In order to achieve the above object, a resin composition for a sealing material of the present invention is a solvent-free sealing material containing the following (A) and (B) and dimethylol dicyclopentane diacrylate as essential components: It is a resin composition, Comprising: The compounding quantity of the following (B) takes the structure that it is 30 to 70 weight% with respect to the whole resin composition.
(A) reacting a vinyl polymer having a number average molecular weight of 500 to 20000 containing a hydroxyl group in a side chain having a hydroxyl equivalent weight (OHV) of 5 to 200 mgKOH / g and an isocyanate compound containing a (meth) acryloyl group. An acrylic polymer having a (meth) acryloyl group in the side chain, obtained by:
(B) An inorganic filler having an average particle size of 0.05 to 0.2 μm.

That is, the present inventors have obtained a resin composition that can be a sealing material (sealing material) excellent in solvent resistance and chemical resistance in addition to low moisture permeability, adhesiveness, transparency, and weather resistance. A series of research was repeated. As a result, an acrylic polymer (A) having a (meth) acryloyl group in the side chain, an inorganic filler (B) having an average particle size of 0.05 to 0.2 μm , dimethylol dicyclopentane diacrylate , In addition to low moisture permeability, adhesiveness, transparency, and weather resistance, it was found that excellent solvent resistance and chemical resistance were obtained, and the present invention was reached. That is, by using the acrylic polymer having the specific structure, particularly when the functional device is used outdoors, excellent weather resistance is exhibited. In addition, by using an inorganic filler having a specific particle size for this, in particular, in addition to reducing moisture permeability, transparency is improved with respect to ultraviolet rays, so that the curability during ultraviolet curing is not impaired. As a result, the excellent characteristics can be obtained from the synergistic effect of the combined use of the two.

As described above, the present invention relates to (A) an acrylic polymer having a (meth) acryloyl group in the side chain, (B) an inorganic filler having an average particle size of 0.05 to 0.2 μm , and dimethylol. It is a resin composition containing dicyclopentane diacrylate as an essential component. For this reason, not only excellent low moisture permeability, adhesiveness, transparency and weather resistance, but also excellent properties such as solvent resistance and chemical resistance are provided. Therefore, the resin composition of the present invention is very useful as a sealing material (sealing material) for various functional devices.

  And when the number average molecular weight of the said specific acrylic polymer (A) is 500-20000, with the improvement of the applicability | paintability of a resin composition, intensity | strength, adhesiveness, weather resistance, solvent resistance, and chemical resistance Is further improved.

  Further, when the inorganic filler (B) is a spherical silica particle, the surface can be arbitrarily designed from hydrophobic to hydrophilic, and the affinity with the resin component can be improved.

Furthermore, in the resin composition of the present invention, when dimethylol dicyclopentane diacrylate, which is a polyfunctional acrylate compound , is included as a reactive diluent, the viscosity of the resin composition is reduced, thereby improving coatability. In addition, since it acts as a cross-linking agent, it is further excellent in low moisture permeability, solvent resistance and chemical resistance.

  And when the said inorganic filler (B) is that by which the surface was chemically modified, affinity with the resin component with the said (A) component etc. improves further, and uncured solution of This will contribute to a reduction in viscosity and an improvement in dispersibility of the inorganic filler (B).

  Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

The resin composition of the present invention is obtained using a specific acrylic polymer (component A), an inorganic filler (component B) having a specific particle size, and dimethylol dicyclopentane diacrylate. It is. The resin composition of the present invention includes sealing materials (sealing materials) for various functional devices, and many of the various functional devices to be sealed are plastic substrates and glass substrates. Since it has a structure in which substrates with electrodes are arranged to face each other, it is a solventless resin composition that does not contain a solvent or a volatile component that causes voids. Moreover, since the resin composition of the present invention also has thixotropic properties, it exhibits a liquid that is excellent in application properties such as dispense coatability and screen printing. In the present invention, (meth) acryloyl is acryloyl or methacryloyl, (meth) acrylate is acrylate or methacrylate, (meth) acrylic acid is acrylic acid or methacrylic acid, and (meth) acryloxy is acryloxy or Each means methacryloxy.

  The specific acrylic polymer (component A) has a (meth) acryloyl group in the side chain, a vinyl polymer containing a hydroxyl group in the side chain, and a (meth) acryloyl group-containing isocyanate compound, It is obtained by reacting.

  The vinyl polymer containing a hydroxyl group in the side chain is, for example, a vinyl polymer obtained by a high-temperature continuous polymerization method of a vinyl monomer containing a hydroxyl group, a vinyl monomer not containing a hydroxyl group, or other vinyl monomers. It is a liquid random copolymer having a number average molecular weight of 500 to 20000 and a hydroxyl equivalent (OHV) of about 5 to 200 mgKOH / g.

  As the vinyl monomer containing a hydroxyl group, a hydroxyl group-containing (meth) acrylate is used. For example, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, pentaerythritol (meth) Examples thereof include acrylate and glycerin (meth) acrylate. These may be used alone or in combination of two or more. Of these, hydroxyethyl (meth) acrylate is preferably used from the viewpoint of good random copolymerizability.

  As the vinyl monomer not containing a hydroxyl group, (meth) acrylic acid ester is used. For example, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl ( (Meth) acrylate, t-butyl (meth) acrylate, isooctyl (meth) acrylate, neopentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, styryl (meth) acrylate, Isobornyl (meth) acrylate, tricyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, Methylaminoethyl (meth) acrylate, chloroethyl (meth) acrylate, monofunctional (meth) acrylates such as trifluoroethyl (meth) acrylate. These may be used alone or in combination of two or more. Among them, preferably, from the viewpoint of achieving both flexibility and tack-free properties of the resulting cured product, the ester residue of (meth) acrylate has 1 to 20 carbon atoms, and butyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and cyclohexyl (meth) acrylate are used.

  Examples of the other vinyl monomers include crotonic acid esters, α-olefins, chloroethylenes, vinyl ethers, vinyl esters, isopropenyl ethers, allyl ethers, allyl esters, aromatic vinyl monomers Examples thereof include a monomer and (meth) acrylic acid. These may be used alone or in combination of two or more.

  The use ratio of the vinyl monomer containing a hydroxyl group and the vinyl monomer not containing a hydroxyl group is a liquid having a hydroxyl group equivalent (OHV) of a vinyl polymer containing a hydroxyl group in the obtained side chain of about 5 to 200 mgKOH / g. What is necessary is just to set arbitrarily the mixture ratio of each monomer with which it uses for reaction so that it may become a random copolymer. That is, if the hydroxyl equivalent (OHV) is too small, the cross-linking density of the cured product of the resin composition of the present invention to be obtained becomes insufficient, the strength tends to be insufficient, and sufficient low moisture permeability, adhesion, transparency, weather resistance. This is because there is a tendency that it may not be possible to exert its properties and solvent resistance / chemical resistance. On the other hand, if the hydroxyl equivalent (OHV) is too large, the glass transition temperature (Tg) of the resulting cured product of the resin composition of the present invention tends to be high, the elastic modulus is high, and sufficient adhesiveness may not be exhibited. This is because a tendency to occur is observed.

  The vinyl polymer containing a hydroxyl group in the side chain obtained by using each of the above monomers is obtained by a continuous polymerization method at a high temperature (for example, 150 to 350 ° C.), and has a number average molecular weight of 500 to 20000. A polymer is obtained. Among these, a liquid polymer having a number average molecular weight of 1000 to 15000 is preferable from the viewpoints of coating property, strength, adhesion, weather resistance, solvent resistance and chemical resistance. In addition, in this invention, a number average molecular weight shows the number average molecular weight by polystyrene conversion measured by gel permeation chromatography (GPC).

  On the other hand, examples of (meth) acryloyl group-containing isocyanate compounds used in the present invention include (meth) acrylic acid such as 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 1,1-bis (acryloxymethyl) ethyl isocyanate, and the like. Examples include loxyisocyanate compounds. These may be used alone or in combination of two or more.

  As described above, the specific acrylic polymer (component A) used in the present invention is a reaction between a vinyl polymer containing a hydroxyl group in the side chain and an isocyanate compound containing a (meth) acryloyl group. Is obtained. And the synthesis | combination is 30-30 degreeC by heating from room temperature (about 20 degreeC) depending on the case in catalysts, such as metals, such as titanium and tin, and organic metal salts, such as dibutyltin laurate, in inert gas atmosphere. The acrylic polymer having a (meth) acryloyl group in the side chain is obtained at room temperature (25 ± 15 ° C.).

The degree of progress of modification in the synthesis reaction of the specific acrylic polymer (component A) is, for example, in the infrared absorption spectrum, the characteristic absorption band (near 2260 cm ⁻¹ ) derived from isocyanate groups decreases with the progress of the reaction. Therefore, it can be confirmed by measuring the characteristic absorption band derived from this isocyanate group. The end point of modification in the synthesis reaction can be confirmed by disappearance of the characteristic absorption band derived from the isocyanate group.

  Insulating spherical inorganic fillers such as silica powder, alumina powder, titanium oxide powder, calcium carbonate powder, calcium silicate powder and the like as the inorganic filler (B component) having a specific particle size used together with the above A component The agent is opened. These may be used alone or in combination of two or more. Among these, in terms of dispersibility in the hydrogenated elastomer derivative, the surface of the inorganic filler can be arbitrarily designed from hydrophobic to hydrophilic, and the silica powder is used from the viewpoint of easily improving the affinity with the resin component. It is preferable to use a spherical silica powder having an average particle diameter of 0.3 μm or less. Examples of the spherical silica powder include fused spherical silica powder obtained by melting crushed silica powder.

  The average particle diameter of the inorganic filler is 0.05 to 0.2 μm. That is, when the average particle size is too small and the particles become ultrafine, the specific surface area becomes too large, and the filling amount tends to be reduced, and the effect of reducing the moisture permeability of the cured product tends to be insufficient. When the particle diameter is too large, the transparency of the cured product is impaired, and in the case of ultraviolet curing, the curability tends to be impaired.

Further, the maximum particle size of the inorganic filler is preferably 10 μm or less, particularly preferably 1 μm or less. Then, as the specific surface area of the inorganic filler is preferably from 10 to 100 m ² / g, more preferably 20 to 50 m ² / g.

  The average particle size and the maximum particle size of the inorganic filler can be measured using, for example, a laser diffraction / scattering particle size distribution analyzer. The specific surface area of the inorganic filler can be measured by, for example, a pore characteristic measuring device (for example, Autosorb 3B type manufactured by Cantachrome) by a nitrogen adsorption method. And the said average particle diameter and specific surface area are the values derived | led-out using the said measuring apparatus using the sample arbitrarily extracted from the population of an inorganic filler.

  The inorganic filler is preferably surface-treated by chemically modifying its surface. Thereby, affinity with resin components, such as the said specific acrylic polymer (A component), improves more, the viscosity fall of an uncured solution and the dispersibility of an inorganic filler improve.

  The compound used for such chemical modification may be any compound that reacts with a functional group such as a hydroxyl group or a carboxyl group present on the surface of the inorganic filler, and more preferably a silane coupling agent or a silylated compound. Reactive silane compounds such as agents, titanate compounds, isocyanate compounds and the like. These may be used alone or in combination of two or more.

  The compound used for the chemical modification is the same as the surface treatment method of a conventionally known inorganic filler, for example, a method of surface-treating the inorganic filler by blending the compound together with the inorganic filler in an organic solvent. Used in the method. The amount of the compound used in such a surface treatment method is preferably set, for example, to an addition ratio that provides a minimum covering area with respect to the inorganic filler.

  Examples of the silane coupling agent include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycid. Xylpropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N 2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-amino Propyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltriethoxysilane, N- (vinylbenzyl) -2-aminoethyl- 3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) Examples thereof include tetrasulfide and 3-isocyanatopropyltriethoxysilane. These may be used alone or in combination of two or more.

  Examples of the silylating agent include methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, trifluoropropyltrichlorosilane, hexamethyldisilazane, and the like. These may be used alone or in combination of two or more.

  Examples of the titanate compound include tetraalkyl titanate compounds such as tetraisopropyl titanate and tetra-n-butyl titanate, and other low molecular weight condensates. These may be used alone or in combination of two or more.

  Examples of the isocyanate compound include (meth) acryloxy isocyanate compounds such as 2-isocyanate ethyl methacrylate, 2-isocyanate ethyl acrylate, and 1,1-bis (acryloxymethyl) ethyl isocyanate. These may be used alone or in combination of two or more.

  The compounding quantity of the inorganic filler (B component) provided with the said specific particle diameter is set to 30 to 70 weight% with respect to the whole resin composition, More preferably, it is 40 to 60 weight%. That is, if the blending amount of the B component is too small, the low moisture permeability of the sealing material tends to be insufficient. If the blending amount of the B component is too large, the liquid viscosity of the uncured resin composition is extremely high. This is because it tends to be high and interfere with coating.

  A polymerization initiator can be arbitrarily mix | blended with the resin composition of this invention with the said A component and B component.

  Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator. More preferably, in the process of curing the resin composition of the present invention, a photopolymerization initiator using ultraviolet rays is used for the purpose of avoiding adverse effects on the functional device due to heating.

  As the thermal polymerization initiator, for example, a peroxide such as dicumyl peroxide, or a radical generator such as 2,2′-azobis (2-methylpropionitrile) can be used.

  As the photopolymerization initiator, for example, a photo radical generator that is a UV curing agent using ultraviolet (UV) is used. Specifically, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl Examples include -1- (4-methylthiophenyl) -2-morpholinopropan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. These may be used alone or in combination of two or more.

  The blending amount of the photopolymerization initiator is preferably set in the range of 0.1 to 30% by weight, more preferably in the range of 0.5 to 20% by weight, based on the entire resin composition of the present invention. That is, when the amount of the photopolymerization initiator is too small, the degree of polymerization tends to be insufficient, and when too large, the decomposition residue increases, the durability of the sealing material decreases, and the solvent resistance / This is because the chemical resistance tends to decrease.

The resin composition of the present invention, as a reactive diluent, also as a diluent at each component formulation, and at the time of curing you containing polyfunctional acrylate compounds which act as crosslinking agents. Examples of the polyfunctional acrylate compounds, from the viewpoint of compatibility with the hydrogenated elastomer derivative is good, dimethylol dicyclopentane diacrylate is found using.

  Furthermore, the resin composition of the present invention includes, in addition to the above-mentioned respective blending components, other additives depending on its use, monofunctional (meth) acrylates, antioxidants, antifoaming agents, surfactants, A coloring agent, an organic filler, various spacers, etc. can be suitably mix | blended as needed. These may be used alone or in combination of two or more.

  The resin composition of the present invention is, for example, blended with a specific acrylic polymer (component A), an inorganic filler (component B) having a specific particle size, and other blended components, and kneaded such as three rolls. It can be produced by mixing and kneading using a disperser.

  The resin composition of the present invention thus obtained is provided as a cured product by light irradiation such as ultraviolet irradiation using a UV lamp or the like. In addition, after light irradiation such as ultraviolet irradiation, curing is performed by post-curing at a predetermined temperature as necessary to form a sealing layer (sealing part, sealing part) with a sealing material (sealing material). Is done.

  As the light source used for the ultraviolet irradiation, known various light sources such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp and the like that effectively irradiate ultraviolet rays are used. On the other hand, what effectively irradiates visible light, such as a photographic flood bulb and a solar lamp, is also used as light irradiation other than ultraviolet irradiation.

  When sealing various functional devices using the resin composition of the present invention, in order to further improve the adhesion between the cured resin composition (sealing material, sealing material) and the electrode substrate or substrate. It is more effective and preferable to previously coat the surface of the sealing portion with a silane coupling agent.

  Examples of the silane coupling agent include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycid. Xylpropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N 2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-amino Propyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltriethoxysilane, N- (vinylbenzyl) -2-aminoethyl- 3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) Examples thereof include tetrasulfide and 3-isocyanatopropyltriethoxysilane. These may be used alone or in combination of two or more.

  In the various functional devices, the pair of electrode substrates, and at least one of the electrode substrate and the cap material (lid) are arranged to face each other at a predetermined interval, and the pair of electrode substrates and the electrode substrate and the cap material ( After covering the surface of at least one peripheral portion of the lid) with a silane coupling agent, a sealing portion is formed which is disposed while maintaining a gap. As the coating treatment of the silane coupling agent at this time, for example, an alcohol solution of a silane coupling agent mixed with 0.1 to 2% by weight of methanol or the like is applied to the surface of the sealing portion, and then at 100 ° C. It is preferable to dry for 5 minutes.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

[Example 1]
As a vinyl polymer containing a hydroxyl group, a liquid acrylic polymer having a viscosity of 6000 mPa · s, a number average molecular weight of 2000, and a hydroxyl group equivalent (OHV) of 110 mgKOH / g (manufactured by Toagosei Co., Ltd., ARUFON UH-2032) is 40 g (0 as OH group). 0.084 mol) and 14.6 g (0.0941 mol) of 2-isocyanatoethyl methacrylate were charged in a reaction vessel, and kept at 50 ° C. in a hot water bath under a nitrogen stream. Thereafter, 0.028 g of dibutyltin laurate (catalyst) (0.19% by weight with respect to 2-isocyanatoethyl methacrylate) was added and held for 8 hours. The disappearance of 2260 cm ⁻¹ was confirmed using an infrared absorption spectrum (FT-IR: manufactured by Thermo Electron, FT-IR200 type), and an acrylic polymer having a methacryloyl group content in the side chain was prepared.

On the other hand, 100 g of spherical silica powder (specific surface area 28 m ² / g) having an average particle size of 0.1 μm (maximum particle size of 0.2 μm), 64.55 g of hexamethyldisilazane, and 250 g of toluene were put into a reaction vessel, and ultrasonic waves were added. For 2 hours at room temperature (25 ° C.). Then, it isolate | separated using the filter paper, and it wash | cleaned and dried with toluene and ethanol, and obtained the spherical silica powder which hydrophobized the surface.

  Next, 7 g of an acrylic polymer having a methacryloyl group in the side chain, 10 g of spherical silica powder having a hydrophobic surface, 3 g of dimethylol dicyclopentane diacrylate (tricyclodecane dimethanol diacrylate), as a photopolymerization initiator Prepare 0.5 g of photo radical polymerization initiator (Ciba Specialty Chemicals, Irgacure 651), premix them in a mortar under light shielding, and then knead and disperse with 3 rolls for the desired sealing material A resin composition was prepared.

The obtained resin composition for a sealing material was sandwiched between two separators, which are polyester films having a thickness of 50 μm, with a gap (gap) adjusted to 100 μm, and then irradiated with ultraviolet rays under a nitrogen gas stream using an ultraviolet lamp. (10 mW / cm ² × 300 seconds) to prepare a cured film. Using the obtained cured film, moisture permeability test by cup method (JIS Z 0208), weight change and color observation by visual immersion in 0.1M iodine acetonitrile solution at room temperature (25 ° C.) for 168 hours (visual observation) Determination of discoloration by) and a solvent resistance test, and an elastic modulus was measured by a viscoelasticity test apparatus (RSA3 type, manufactured by TA Instruments).

Further, in the same manner as described above, two slide glass plates (260 mm × 76 mm × thickness of 1. mm) having a gap adjusted to 50 μm and pre-adhering the glass surface by applying 3-acryloxypropyltrimethoxysilane in advance. 2 mm), and a glass / glass adhesion test piece was obtained by irradiating with an ultraviolet ray under a nitrogen gas stream (3000 mJ / cm ² ) using an ultraviolet lamp. It was left for 168 hours in a high humidity and high temperature bath of 85% RH. Then, the adhesiveness (presence / absence of peeling) of the two slide glass plates was evaluated.

Further, in the same manner as described above, the gap was adjusted to 50 μm, the resin composition for sealing material was sandwiched between two slide glass plates (260 mm × 76 mm × thickness 1.2 mm), and an ultraviolet lamp was used. After ultraviolet ray irradiation (3000 mJ / cm ² ) under a nitrogen gas stream to obtain a test piece, a super-energy irradiation tester (UE-1DEC type, manufactured by Suga Test Instruments Co., Ltd.) was used at 90 W / m ² . Irradiation was for 168 hours. The light transmittance retention at a wavelength of 350 nm before and after the irradiation was measured and evaluated using a measuring apparatus (manufactured by Hitachi, spectrophotometer U-3900 type).

[Example 2]
3 g of acrylic polymer having a methacryloyl group content in the side chain produced in Example 1 above, 10 g of surface-hydrophobized spherical silica powder similarly produced in Example 1 above, dimethylol dicyclopentane diacrylate (tricyclo Prepare 7 g of decanedimethanol diacrylate) and 0.5 g of photo radical polymerization initiator (Ciba Specialty Chemicals, Irgacure 651), premix them in a mortar under light shielding, and then knead and disperse with 3 rolls. Thus, a desired resin composition for a sealing material was produced. Other than that, the measurement and evaluation by various characteristic tests were performed in the same manner as in Example 1.

Example 3
As a vinyl polymer containing a hydroxyl group, a liquid acrylic polymer (ARUFON UH-2000, manufactured by Toagosei Co., Ltd.) having a viscosity of 14,000 mPa · s, a number average molecular weight of 11,000, and a hydroxyl group equivalent (OHV) of 20 mgKOH / g is 0 g as an OH group. 0.0143 mol) and 2.65 g (0.0171 mol) of 2-isocyanatoethyl methacrylate were put into a reaction vessel and kept at 50 ° C. in a hot water bath under a nitrogen stream. Thereafter, 0.006 g of dibutyltin laurate (catalyst) (0.23% by weight with respect to 2-isocyanatoethyl methacrylate) was added and held for 8 hours. The disappearance of 2260 cm ⁻¹ was confirmed using an infrared absorption spectrum (FT-IR: manufactured by Thermo Electron, FT-IR200 type), and an acrylic polymer having a methacryloyl group content in the side chain was prepared. Otherwise, a resin composition for a sealing material was prepared in the same manner as in Example 1, and measurements and evaluations by various characteristic tests were performed in the same manner as in Example 1 using this resin composition for a sealing material.

[Comparative Example 1]
As a vinyl polymer not containing a hydroxyl group, 3 g of a liquid acrylic polymer (manufactured by Toagosei Co., Ltd., ARUFON UP-1030) having a viscosity of 5000 mPa · s, a number average molecular weight of 6000, and a hydroxyl group equivalent (OHV) of 0 mg KOH / g, Example 1 above 10 g of spherical silica powder having a hydrophobized surface, 7 g of dimethylol dicyclopentane diacrylate (tricyclodecane dimethanol diacrylate), and 0.5 g of a photo radical polymerization initiator (Ciba Specialty Chemicals, Irgacure 651) Each was prepared, premixed in a mortar under light shielding, and then kneaded and dispersed with three rolls to produce the desired resin composition for a sealing material. Other than that, the measurement and evaluation by various characteristic tests were performed in the same manner as in Example 1.

[Comparative Example 2]
Using 100 g of spherical silica powder (specific surface area 6.2 m ² / g) having an average particle size of 0.7 μm (maximum particle size of 3.2 μm), a spherical silica powder having a surface hydrophobized in the same manner as in Example 1 was obtained. . And while producing the resin composition for sealing materials similarly to the said Example 1, measurement and evaluation by various characteristic tests were performed like Example 1 using this resin composition for sealing materials.

[Comparative Example 3]
Using 100 g of spherical silica powder (specific surface area 6.2 m ² / g) having an average particle size of 0.4 μm (maximum particle size 1.0 μm), a spherical silica powder having a surface hydrophobized in the same manner as in Example 1 was obtained. . And while producing the resin composition for sealing materials similarly to the said Example 1, measurement and evaluation by various characteristic tests were performed like Example 1 using this resin composition for sealing materials.

  The measurement and evaluation results by various characteristic tests of these examples and comparative examples are also shown in Table 1 below.

  From the above results, the example products had a low moisture permeability and a low rate of weight change. Furthermore, the degree of discoloration was also suppressed, peeling did not occur and the adhesiveness was excellent, the light transmittance retention was high, and the transparency was excellent.

  On the other hand, the product of Comparative Example 1 which does not use an acrylic polymer having a (meth) acryloyl group in the side chain as the A component of the present invention has a high light transmittance retention and is excellent in terms of transparency. there were. However, high moisture permeability and high weight change rate were obtained. Moreover, it was confirmed that the film was broken and turned blackish brown. Further, it can be seen that peeling occurs and the adhesiveness is poor. Further, Comparative Examples 2 and 3 using a spherical silica powder having a large average particle diameter had a low weight change rate, and the degree of discoloration was suppressed. Moreover, peeling did not occur and the adhesiveness was excellent. However, in the measurement of the light transmittance and the light transmittance retention rate, the light transmittance of 350 nm was not transmitted before the irradiation, so that it was not subjected to the light transmittance retention measurement test.

  The resin composition of the present invention includes organic EL display devices, various display electronic devices such as liquid crystal display devices and electrophoretic display devices, organic EL lighting devices, optical devices such as optical elements and optical waveguides, thin film silicon solar cells, organic It is useful for sealing materials and sealing materials for various functional devices such as thin film solar cells and solar cells such as dye-sensitized solar cells.

Claims (4)

The following (A) and (B) and a solvent-free resin composition for a sealing material containing dimethylol dicyclopentane diacrylate as essential components, wherein the blending amount of the following (B) is the whole resin composition The resin composition for sealing materials, characterized by being 30 to 70% by weight based on the weight.
(A) reacting a vinyl polymer having a number average molecular weight of 500 to 20000 containing a hydroxyl group in a side chain having a hydroxyl equivalent weight (OHV) of 5 to 200 mgKOH / g and an isocyanate compound containing a (meth) acryloyl group. An acrylic polymer having a (meth) acryloyl group in the side chain, obtained by:
(B) An inorganic filler having an average particle size of 0.05 to 0.2 μm.   The resin composition for a sealing material according to claim 1, wherein the number average molecular weight of the acrylic polymer having a (meth) acryloyl group in the side chain (A) is 500 to 20,000.   The resin composition for a sealing material according to claim 1 or 2, wherein the inorganic filler (B) is a spherical silica powder. The resin composition for a sealing material according to any one of claims 1 to 3 , wherein the surface of the inorganic filler (B) is chemically modified.