JP4796322B2 - Novel thermosetting resin composition - Google Patents

Description

  The present invention relates to a novel thermosetting resin composition that provides a cured product having excellent curability, high optical transparency, and excellent heat resistance and light resistance.

  In general, epoxy resins are widely used in adhesives, paints, civil engineering and building materials, electrical / electronic component materials, and insulating materials due to their excellent characteristics such as adhesion, mechanical properties, heat resistance, chemical resistance, and electrical properties. Yes.

  Optical component materials used as sealants for light-emitting diodes, raw materials for plastic lens molding, adhesives for connecting optical cables, etc., sealants for solar cells and outdoor electric bulletin boards, and adhesives Therefore, it is required to have light resistance that is difficult to cause coloring and alteration deterioration even when it repeatedly receives strong light from the short wavelength region of visible light to the ultraviolet region, and has heat resistance.

  A representative example of a resin for optical parts that has been used in the past is a transparent epoxy resin obtained by blending a bisphenol A type epoxy resin and an acid anhydride curing agent and thermosetting, but there is a problem of poor light resistance. It was.

  Under such circumstances, alicyclic epoxy resin cured products (Patent Document 1) and hydrogenated bisphenol A type epoxy resin cured products (Patent Document 2) thermally cured with an acid anhydride curing agent have been proposed. However, the alicyclic epoxy resin cured product is excellent in light resistance and heat resistance, but the hue after curing is poor, and the hydrogenated bisphenol A type epoxy resin cured product is excellent in light resistance. There was a problem of being bad.

  In addition, a cured product obtained by thermal cationic polymerization of a hydrogenated bisphenol A type epoxy resin having a low residual chlorine concentration with a latent catalyst has been proposed as a resin that can be stored in one liquid and has excellent light resistance and heat resistance. (Patent Document 3). However, this cured product also has a problem in heat resistance because it is mainly composed of hydrogenated bisphenol A type epoxy as described above.

  There is also a method of using a silicone resin instead of an epoxy resin. However, for example, when used as a sealant for a light emitting diode, the silicone resin has a low refractive index compared to an epoxy resin and has low adhesion to the element, so the light extraction efficiency from the light emitting diode element is reduced, There are many difficulties in obtaining a bright light-emitting diode.

Therefore, a thermosetting resin composition excellent in transparency, light resistance and heat resistance has been demanded.
JP 2003-221490 A Japanese Patent Laid-Open No. 2003-12896 JP 2003-73452 A

  An object of the present invention is to provide a thermosetting resin composition that has high optical transparency, is excellent in curability, light resistance, and heat resistance, is hardly colored, and hardly undergoes alteration or deterioration.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that cyclohexane-1,2,4-tricarboxylic acid, cyclohexane-1,3,4-tricarboxylic acid-3,4-anhydride, cyclohexane- An epoxy resin (A) comprising a compound represented by the following general formula (1) obtained by reacting at least one compound selected from 1,3,5-tricarboxylic acid with epihalohydrin and a curing agent (B ) As an essential component, the present inventors have found that the above object can be achieved, and have completed the present invention.

  The thermosetting resin composition of the present invention is excellent in curability, and the cured product is colorless and transparent, excellent in heat resistance, excellent in light resistance without deterioration due to various wavelengths of light emitted from a light source, The light resistance to light with strong energy from the short wavelength region of the visible light region of blue light or violet light to the ultraviolet region is particularly excellent.

  This resin composition is useful as a sealant for light emitting diodes, a raw material for molding plastic lenses, an adhesive for connecting optical cables, a sealant for solar cells and outdoor electric bulletin boards, and an adhesive. . In particular, it is useful as a sealant for near-ultraviolet and white light emitting diodes.

で示される化合物が主成分であるエポキシ樹脂（Ａ）は公知の技術を用いてシクロヘキサン−１，２，４−トリカルボン酸、シクロヘキサン−１，３，４−トリカルボン酸―３，４−無水物、シクロヘキサン−１，３，５−トリカルボン酸から選ばれる１種以上の化合物とエピハロヒドリンとを反応させることで合成する事が出来る。 In the present invention

The epoxy resin (A) whose main component is a compound represented by the formula is cyclohexane-1,2,4-tricarboxylic acid, cyclohexane-1,3,4-tricarboxylic acid-3,4-anhydride using a known technique, It can be synthesized by reacting one or more compounds selected from cyclohexane-1,3,5-tricarboxylic acid with epihalohydrin.

  The said epoxy resin (A) may be used individually by 1 type, and may mix | blend and use arbitrary other epoxy resins or silicone resins as needed.

  Examples of the curing agent (B) in the present invention include polycarboxylic acids and / or acid anhydrides thereof, cationic polymerization initiators, amine-based curing agents and the like. Among these, polycarboxylic acids and / or acid anhydrides thereof and cationic polymerization initiators are preferable, and acid anhydrides of cycloaliphatic polycarboxylic acids having excellent light resistance are more preferable.

  Specific examples of the polycarboxylic acid and / or acid anhydride thereof in the present invention include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, norbornane-2,3-dicarboxylic acid Anhydride, methylnorbornane-2,3-dicarboxylic acid anhydride, cyclohexane-1,2,4-tricarboxylic acid, cyclohexane-1,3,5-tricarboxylic acid, cyclohexane-1,3,4-tricarboxylic acid-3, 4-Anhydride, maleic anhydride, phthalic anhydride, succinic anhydride, dodecyl succinic anhydride, pyromellitic anhydride, trimellitic anhydride, etc. can be mentioned. Among these, cycloaliphatic polycarboxylic acid and / or acid anhydride thereof excellent in light resistance are preferable, and methylhexahydrophthalic anhydride, norbornane-2,3-dicarboxylic acid anhydride, methylnorbornane-2, excellent in handling properties, 3-dicarboxylic anhydride is more preferred.

  The content of the polycarboxylic acid and / or acid anhydride thereof is preferably in the range of 0.5 to 1.5 equivalents relative to 1 equivalent of the epoxy group of the epoxy resin (A), and has heat resistance and light resistance. In consideration, it is more preferably in the range of 0.6 to 1.2 equivalents.

  Polycarboxylic acid and / or acid anhydride thereof may be used alone or in combination of two or more as required.

As the cationic polymerization initiator, at least one cation selected from aromatic sulfonium, aromatic iodonium, aromatic diazonium, aromatic ammonium, and the like, and at least one selected from BF ₄ ⁻ , PF ₆ ⁻ , and SbF ₆ ^— An onium salt composed of the anion. Such a cationic polymerization initiator may be used individually by 1 type, and may use 2 or more types together. Among these, those having SbF ₆ ^— as an anion are particularly preferable because of fast curing.

  Specific examples of the aromatic sulfonium salt-based cationic polymerization initiator include bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluoroantimonate. Bis [4- (diphenylsulfonio) phenyl] sulfide bistetrafluoroborate, bis [4- (diphenylsulfonio) phenyl] sulfide tetrakis (pentafluorophenyl) borate, (2-ethoxy-1-methyl-2-oxoethyl) ) Methyl-2-naphthalenylsulfonium hexafluorophosphate, (2-ethoxy-1-methyl-2-oxoethyl) methyl-2-naphthalenylsulfonium hexafluoroatimonate, (2-ethoxy-1-methyl) Ru-2-oxoethyl) methyl-2-naphthalenylsulfonium tetrafluoroborate, (2-ethoxy-1-methyl-2-oxoethyl) methyl-2-naphthalenylsulfonium tetrakis (pentafluorophenyl) borate, diphenyl-4 -(Phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenylthio) phenylsulfonium hexafluoroatimonate, diphenyl-4- (phenylthio) phenylsulfonium tetrafluoroborate, diphenyl-4- (phenylthio) phenylsulfonium tetrakis (penta Fluorophenyl) borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, trif Nylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- ( Di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluoroantimonate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bistetrafluoro Examples thereof include borates and bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide tetrakis (pentafluorophenyl) borate.

  Specific examples of aromatic iodonium salt-based cationic polymerization initiators include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, bis (dodecylphenyl) Iodonium hexafluorophosphate, bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1- Methylethyl) phenyliodonium hexafluorophosphate, 4-methylphenol 4- (1-methylethyl) phenyliodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrafluoroborate, 4-methylphenyl-4- (1-methylethyl) phenyl Examples thereof include iodonium tetrakis (pentafluorophenyl) borate.

  Specific examples of the aromatic diazonium salt-based cationic polymerization initiator include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis (pentafluorophenyl) borate.

  Specific examples of the aromatic ammonium salt cationic polymerization initiator include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetra Fluoroborate, 1-benzyl-2-cyanopyridinium tetrakis (pentafluorophenyl) borate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, Examples include 1- (naphthylmethyl) -2-cyanopyridinium tetrafluoroborate, 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) borate, and the like. The

  A cationic polymerization initiator may be used individually by 1 type, and may be used together 2 or more types as needed.

  Specific examples of the amine curing agent include diethylenetriamine <DETA>, triethylenetetramine <TETA>, tetraethylenepentamine <TEPA>, m-xylenediamine <MXDA>, trimethylhexamethylenediamine <TMD>, 2-methylpenta Methylenediamine <2-MPMDA>, diethylaminopropylamine <DEAPA>, isophoronediamine <IPDA>, 1,3-bisaminomethylcyclohexane <1,3-BAC>, bis (4-aminocyclohexyl) methane <PACM>, Norbornenediamine <NBDA>, 1,2-diaminocyclohexane <1,2-DCH>, diaminodiphenylmethane <DDM>, metaphenylenediamine <MPDA>, diaminodiphenylsulfone <DDS>, N-aminoethylpi Perazine <N-AEP> and the like can be mentioned. These modified products such as MXDA modified products and IPDA modified products may also be used.

  The amine curing agent may be used alone or in combination of two or more as required.

  Moreover, you may make the thermosetting epoxy resin composition of this invention contain a hardening accelerator other than said component in the range which does not impair the physical property of hardened | cured material. Examples of the curing accelerator include phosphines and / or their quaternary salts, tertiary amines or imidazoles and / or their organic carboxylates, organic carboxylic acid metal salts, and metal-organic chelate compounds. . Of these, phosphines and / or quaternary salts thereof having excellent heat resistance are preferred.

  The content of the curing accelerator is preferably 0 to 5.0 parts by weight with respect to 100 parts by weight of the epoxy resin (A), and 0.1 to 3 considering the balance of curability, heat resistance and light resistance. More preferably, it is 0.0 parts by weight.

  Specific examples of the curing accelerator include triphenylbenzylphosphonium tetraphenylborate, tetrabutylphosphonium diethylphosphorodithioate, tetraphenylphosphonium bromide, tetrabutylphosphonium acetate, tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium. Benzotriazolate, tetra-n-butylphosphonium tetrafluoroborate, tetra-n-butylphosphonium tetraphenylborate, methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium iodide, ethyltriphenylphosphonium acetate, n-Butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chlora Phosphines such as tetraphenylphosphonium tetraphenylborate and quaternary salts thereof, 2-ethyl-4-methylimidazole <2E4MZ>, 2-phenylimidazole, 1- (2-cyanoethyl) -2-ethyl-4- Methylimidazole <2E4MZ-CN>, 2,4-diamino-6- [2-methylimidazolyl- (1)] ethyl-s-triazine <2MZ-A>, 2-phenylimidazoline <2PZL> 2,3-dihydro- Imidazoles such as 1H-pyrrolo [1,2-a] benzimidazole <TBZ>, tris (dimethylaminomethyl) phenol <DMP-30>, benzyldimethylamine <BDMA>, 1,8-diazabicyclo (5,4, 0) Tertiary amines such as undecene-7 <DBU>, zinc octylate, zinc laurate, Known compounds such as organic carboxylic acid metal salts such as zinc thetearate and tin octylate, metal-organic chelate compounds such as benzoylacetone zinc chelate, dibenzoylmethane zinc chelate and ethyl zinc acetoacetate chelate are included. Particularly preferred are triphenylbenzylphosphonium tetraphenylborate, tetrabutylphosphonium diethylphosphorodithioate, and tetraphenylphosphonium bromide, which are excellent in transparency, light resistance, and heat resistance of the cured product.

  The said hardening accelerator may be used individually by 1 type, and may be used together 2 or more types as needed.

  The thermosetting resin composition of the present invention includes an anti-aging agent, a radical inhibitor, an ultraviolet absorber, an adhesion improver, and a flame retardant, as long as the transparency, heat resistance, and light resistance of the resulting cured product are not impaired. , Surfactant, storage stability improver, ozone degradation inhibitor, light stabilizer, thickener, plasticizer, coupling agent, antioxidant, thermal stabilizer, conductivity enhancer, antistatic agent, radiation blocker A nucleating agent, a phosphorus peroxide decomposing agent, a lubricant, a pigment, an antifoaming agent, a metal deactivator, a stress reducing agent, a physical property adjusting agent, and the like can be added.

  Hereinafter, the details of the present invention will be specifically described with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, parts and% mean weight basis unless otherwise specified.

<Synthesis example>
45 g (0) of cyclohexane-1,2,4-tricarboxylic acid (H-TMA (manufactured by Mitsubishi Gas Chemical Co., Ltd.)) was added to a 1 L four-necked flask equipped with a stirrer, thermometer, condenser and nitrogen inlet tube. .62 equivalents) and 462 g (5 mol) of epichlorohydrin were added, and 1 g of 50% tetramethylammonium chloride aqueous solution was further added as a phase transfer catalyst. Next, after reacting for 2 hours at an internal temperature of 90 ° C., 62 g (0.75 mol) of 48% sodium hydroxide was added dropwise over 2.5 hours under reduced pressure dehydration conditions, and reacted at the same temperature for 1 hour. . After the reaction, the generated sodium chloride, unreacted sodium hydroxide and catalyst were removed by washing with water, and then epichlorohydrin was distilled off under reduced pressure to obtain 72 g of a transparent liquid product. The epoxy equivalent of this product was 138 g / eq, and the total chlorine component was 1.2%.

<Example 1>
According to the formulation shown in Table 1, 100 parts of the liquid product (cyclohexane-1,2,4-tricarboxylic acid triglycidyl ester) obtained in the synthesis example as an epoxy resin (A) and methylhexayl as a curing agent (B) A thermosetting resin composition was obtained by uniformly stirring and mixing 102 parts of hydrophthalic anhydride (Licacid MH-700, manufactured by Shin Nippon Rika Co., Ltd.). The amount of the curing agent (B) is such that the acid anhydride group of the curing agent (B) is 0.85 equivalent per 1 equivalent of the epoxy group of the epoxy resin (A).

  The obtained resin composition was cast into an aluminum container and cured under conditions of 100 ° C. × 2 hours + 120 ° C. × 12 hours. The thickness of the obtained cured product was 5 mm, and the physical properties were evaluated by the following evaluation methods. The results are shown in Table 1.

The evaluation method in the above-mentioned Example is demonstrated below.
<Initial physical properties>
After the resin composition was cured and cooled to room temperature, the total light transmittance and yellowness (yellow index) of the cured product having a thickness of 5 mm were measured. The total light transmittance was measured using a NDH2000 turbidimeter manufactured by Nippon Denshoku Industries Co., Ltd. The yellowness was determined by performing calculations based on data measured with a ND-1001DP color difference meter manufactured by Nippon Denshoku Industries Co., Ltd. The smaller the value of yellowness, the closer it is to colorless and transparent. The smaller the increase in yellowness and the smaller the decrease in total light transmittance, the less the resin is discolored.
<Heat resistance>
The cured product was heated for 72 hours in a hot air dryer at 150 ° C., and then the total light transmittance and yellowness were measured in the same manner as in the above <Initial physical properties>.
<Light resistance>
The cured product was irradiated with ultraviolet light having a light intensity of 25 mW / cm ² at 365 nm for 3 hours with a high-pressure mercury lamp at room temperature, and then the total light transmittance and yellowness were measured in the same manner as in the above <Initial physical properties>.

<Example 2>
According to the formulation shown in Table 1, 86 parts of cyclohexane-1,3,4-tricarboxylic acid-3,4-anhydride (H-TMAn, manufactured by Mitsubishi Gas Chemical Co., Ltd.) is weighed as the curing agent (B). Immediately after heating and dissolving, 100 parts of the liquid product (cyclohexane-1,2,4-tricarboxylic acid triglycidyl ester) obtained in the synthesis example as an epoxy resin (A) is added, and heat curing is performed by mixing with stirring. A functional resin composition was obtained. Heat curing and evaluation were performed by the method shown in Example 1. The results are shown in Table 1.

<Example 3>
According to the formulation shown in Table 1, 102 parts of methylhexahydrophthalic anhydride (Ricacid MH-700, manufactured by Shin Nippon Rika Co., Ltd.) as a curing agent (B), tetrabutylphosphonium diethyl phosphorodithioate (as a curing accelerator) 1 part of Hishicolin PX-4ET (manufactured by Nippon Chemical Industry Co., Ltd.) was weighed and mixed until uniform by heating and stirring to obtain a mixture of a curing agent and a curing accelerator. To the mixture cooled to room temperature, 100 parts of the liquid product (cyclohexane-1,2,4-tricarboxylic acid triglycidyl ester) obtained in the synthesis example as an epoxy resin (A) is added and mixed with stirring to thermosetting. A resin composition was obtained. Heat curing and evaluation were performed by the method shown in Example 1. The results are shown in Table 1.

<Examples 4-6, Comparative Examples 1-6>
According to the formulation shown in Table 1, a cured product was prepared in the same manner as in Example 3 except that each component was mixed, and evaluation was performed by the method shown in Example 1. The results are shown in Table 1.

<Comparative Example 7>
According to the formulation shown in Table 1, a cured product was prepared in the same manner as in Example 1 except that each constituent component was mixed. However, the cured product was insufficient and subsequent evaluation could not be performed.

  As shown in Table 1 above, the thermosetting resin composition of the present invention is excellent in curability, and the thermosetting resin is colorless and transparent, excellent in heat resistance, and with respect to light of various wavelengths emitted from a light source. It was found that the resin is excellent in light resistance without deterioration.

  Can be applied to sealants for near-ultraviolet and white light emitting diodes, raw materials for plastic lens molding, adhesives for connecting optical cables, etc., and sealants and adhesives for solar cells and outdoor electric bulletin boards Therefore, the industrial utility value is extremely large.

Claims (6)

One or more compounds selected from cyclohexane-1,2,4-tricarboxylic acid, cyclohexane-1,3,4-tricarboxylic acid-3,4-anhydride, cyclohexane-1,3,5-tricarboxylic acid and epihalohydrin Is a compound obtained by reacting with general formula (1)

The thermosetting resin composition which contains as an essential component the epoxy resin (A) which the compound shown by (2) is a main component, and the hardening | curing agent (B) which is cycloaliphatic polycarboxylic acid and / or its acid anhydride .   The thermosetting resin composition according to claim 1, comprising a curing accelerator. The thermosetting resin composition according to claim 2 , wherein the curing accelerator is a phosphine and / or a quaternary salt thereof. The thermosetting resin composition in any one of Claims 1-3 which mixed the hardening | curing agent (B) in the ratio of 0.5-1.5 equivalent with respect to 1 equivalent of epoxy groups of an epoxy resin (A). The thermosetting resin composition in any one of Claims 2-4 which mixed the hardening accelerator in the ratio of 0-0.5 weight part with respect to 100 weight part of epoxy resins (A). The thermosetting resin composition according to any one of claims 1 to 5, which is prepared as an optical component material.