JP2015021118A - Two-component potting composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a potting composition excellent in heat resistance and moisture resistance, which shows high fluidity before curing, and lower Tg and higher thermal conductivity of a cured material.SOLUTION: A two-component potting composition formed from a main agent and a curing agent, comprises: a polyfunctional epoxy resin having an epoxy equivalent of 300 g/mol or more; a non-reactive diluent having a flash point of 250°C or more; a polyfunctional amino compound having an active hydrogen equivalent of 100 g/mol or more; a mono-functional phenolic compound having a flash point of 200°C or more; and an inorganic filler. The polyfunctional epoxy resin is included in the main agent and the polyfunctional amino compound is included in the curing agent.

Description

  The present disclosure relates to two-part potting compositions. More particularly, the present invention relates to an epoxy two-part potting composition having thermal conductivity.

  Thermally conductive potting compositions are used for electronic devices such as battery chargers, battery units for electric vehicles and plug-in hybrid vehicles. The potting composition is filled between an electronic component such as a toroidal coil, a transformer coil, and a ferrite core and the wall of the container to fix the position of the electronic component in the container. With regard to epoxy-based potting compositions, potting compositions with various high glass transition temperatures (Tg) and / or low coefficients of thermal expansion (CTE) have been developed, including bisphenol A type epoxy resins and acid anhydrides or polyamines. Has been.

  However, it is a big problem that the base material can be cracked during the heat shock test. The cause of cracking is a CTE mismatch between the substrate and the cured product of the potting composition. In recent years, there has been an increasing demand for highly flexible potting compositions that can absorb stresses resulting from temperature changes. Typical requirements are low Tg and low modulus. Silicone-modified potting compositions and urethane-modified potting compositions have the properties of low Tg and low modulus, but silicone-modified potting compositions are expensive and urethane-modified potting compositions are hot and / or humid. Low durability in the environment. Also, although epoxy based flexible potting compositions have been developed, there remains a need for potting compositions that are less expensive and have higher thermal conductivity.

  Patent Document 1 (US Pat. No. 5,367,006) includes “(a) at least one aliphatic epoxy resin, (b) a stoichiometric amount of at least one aliphatic polyamine curing agent, and (c) effective. A thermally conductive film adhesive comprising an amount of thixotropic agent and (d) about 20 to 50 volume percent of at least one filler based on the total amount of the epoxy resin and the polyamine curing agent.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 10-036804) states that “(a) at least one kind of polysiloxane having a durometer Shore D reading of 45 or less when cured with a stoichiometric amount of diethylenetriamine. A soft epoxy adhesive comprising a combination of an epoxy resin component and (b) a substantial stoichiometric amount of at least one epoxy resin latent hardener component, said combination being rheologically stable at room temperature And a soft epoxy adhesive having a durometer Shore A of less than 95 when cured ".

US Pat. No. 5,367,006 Japanese Patent Laid-Open No. 10-036804

  Provided is a potting composition having high fluidity before curing, lower Tg of the cured product and higher thermal conductivity, and excellent heat resistance and moisture resistance.

According to one embodiment of the present disclosure,
A polyfunctional epoxy resin having an epoxy equivalent of 300 g / mol or more,
A non-reactive diluent with a flash point of 250 ° C. or higher,
A polyfunctional amino compound having an active hydrogen equivalent of 100 g / mol or more,
A two-component potting composition comprising a main component and a curing agent, comprising a monofunctional phenolic compound having a flash point of 200 ° C. or higher, and an inorganic filler,
There is provided a two-component potting composition in which the polyfunctional epoxy resin is contained in a main agent and the polyfunctional amino compound is contained in a curing agent.

  The two-component potting composition of the present disclosure can contain an inorganic filler at a high filling rate, has a low viscosity, and has a low Tg of a cured product. Therefore, for example, a part (for example, a coil) can be fixed in a metal case and used as a potting composition that dissipates heat from the part to the metal case. Further, since the cured product of the potting composition of the present disclosure can reduce stress in a wide temperature range (for example, −40 ° C. to 100 ° C.) from a low temperature to a high temperature, Peeling is prevented and the parts in the case are not damaged. Moreover, the two-component potting composition of the present disclosure is excellent in heat resistance and moisture resistance often required for outdoor use, and is inexpensive because it uses an epoxy resin as a base.

  The above description should not be construed as disclosing all embodiments of the present invention and all advantages related to the present invention.

  Hereinafter, the present invention will be described in more detail for the purpose of illustrating representative embodiments of the present invention, but the present invention is not limited to these embodiments.

  The two-component potting composition according to an embodiment of the present disclosure includes a main agent and a curing agent. The main agent contains a polyfunctional epoxy resin having an epoxy equivalent of 300 g / mol or more, and the curing agent contains a polyfunctional amino compound having an active hydrogen equivalent of 100 g / mol or more. The main agent and the curing agent each further include at least one of a non-reactive diluent having a flash point of 250 ° C. or higher, a monofunctional phenol compound having a flash point of 200 ° C. or higher, and an inorganic filler. The product as a whole comprises a multifunctional epoxy resin, a multifunctional amino compound, a non-reactive diluent, a monofunctional phenolic compound and an inorganic filler.

  In the present disclosure, a “potting composition” is defined as a composition used for the purpose of covering at least a part of the surface of an object of interest and / or fixing the position of the object relative to another object. The material, shape and arrangement of other objects surrounding the composition or on which the potting composition is placed may vary. For example, the potting composition of the present disclosure includes potting materials, sealing materials, underfill materials, filling materials, and the like.

  In the present disclosure, the flash point of the components of the potting composition is a value measured by the Cleveland open method according to JIS K 2265-4: 2007.

  The polyfunctional epoxy resin contained in the main agent is one of the main components for curing the potting composition by reacting with the polyfunctional amino compound to form a crosslinked structure when the main agent and the curing agent are mixed. . As the polyfunctional epoxy resin, a known epoxy resin generally used in an epoxy resin composition can be used. A polyfunctional epoxy resin can be used individually or in combination of 2 or more types, and may be solid or liquid according to the viscosity, shape, etc. of another component.

  The epoxy equivalent of the polyfunctional epoxy resin is about 300 g / mol or more. In some embodiments, the epoxy equivalent weight of the multifunctional epoxy resin is about 350 g / mole or more, about 400 g / mole or more, or about 500 g / mole or more, about 2000 g / mole or less, about 1500 g / mole or less, or about 1000 g / mol or less. By making the epoxy equivalent of a polyfunctional epoxy resin into the said range, favorable fluidity | liquidity can be provided to a potting composition, and intensity | strength required for the hardened | cured material of a potting composition can be ensured. When a mixture of two or more polyfunctional epoxy resins is used, the above epoxy equivalent means the value of the mixture.

  Examples of multifunctional epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, hydrogenated bisphenol F type epoxy resins, alkylene oxide modified bisphenol A type epoxy resins, and alkylene oxide modified bisphenols. Bisphenol epoxy resins such as F-type epoxy resins; alkylphenol novolac epoxy resins such as phenol novolac epoxy resins and cresol novolac epoxy resins; naphthalene epoxies such as naphthalene skeleton modified epoxy resins, methoxynaphthalene modified cresol novolac epoxy resins and methoxynaphthalenedylene methylene epoxy resins Resin; biphenyl epoxy such as biphenyl epoxy resin and tetramethylbiphenyl epoxy resin Fats; such halogenated flame-retarded epoxy resins the epoxy resin; Cardano over glycidyl ether, cardanol epoxy resins, such as cardanol novolak resin. Among these, since it is excellent in compatibility with other components of the potting composition and can impart good fluidity to the potting composition, the alkylene oxide modified bisphenol A type epoxy resin, the alkylene oxide modified bisphenol F type epoxy It is desirable to use a resin and a cardanol epoxy resin, for example, ethylene oxide (EO) modified bisphenol A type epoxy resin, propylene oxide (PO) modified bisphenol A type epoxy resin, ethylene oxide / propylene oxide (EO / PO) modified bisphenol A type. Epoxy resin, ethylene oxide (EO) modified bisphenol F type epoxy resin, propylene oxide (PO) modified bisphenol F type epoxy resin, ethylene oxide / propylene oxide (EO / Etc. O) modified bisphenol F type epoxy resins, especially propylene oxide (PO) modified bisphenol A type epoxy resin can be advantageously used.

  The number average molecular weight of the polyfunctional epoxy resin is a standard polystyrene equivalent value measured by gel permeation chromatography (GPC), and is generally about 600 or more, about 800 or more, or about 1000 or more, and about 5000 or less, about It can be 3000 or less, or about 2000 or less. By setting the number average molecular weight of the polyfunctional epoxy resin within the above range, it is possible to impart good fluidity to the potting composition and to secure the strength necessary for the cured product of the potting composition. The average epoxy functionality of the polyfunctional epoxy resin, i.e. the average number of epoxy groups per molecule, is generally at least 2 and preferably 2-4.

  In some embodiments, the multifunctional epoxy resin is about 10 wt% or more, about 20 wt% or more, or about 25 wt% or more, about 25 wt% or more based on the total weight of the organic components of the potting composition. It is included in an amount of 60% by mass or less, about 50% by mass or less, or about 45% by mass or less. In the present disclosure, the “organic component of the potting composition” means a polyfunctional epoxy resin, a polyfunctional amino compound, a non-reactive diluent, and a monofunctional phenol compound, and an optional component, a dispersant, a reactivity It means an organic compound such as a diluent, and does not include an inorganic compound such as an inorganic filler and a simple element such as carbon black.

  The polyfunctional amino compound contained in the curing agent is one of the main components for curing the potting composition by reacting with the polyfunctional epoxy resin to form a crosslinked structure when the main agent and the curing agent are mixed. is there. As the polyfunctional amino compound, aliphatic polyamine, polyether polyamine, and the like can be used. A polyfunctional amino compound can be used individually or in combination of 2 or more types.

  The active hydrogen equivalent of the polyfunctional amino compound is about 100 g / mol or more. In some embodiments, the active hydrogen equivalent weight of the polyfunctional amino compound is about 110 g / mole or more, about 120 g / mole or more, or about 130 g / mole or more, about 300 g / mole or less, about 250 g / mole or less, or About 200 g / mol or less. By setting the active hydrogen equivalent of the polyfunctional amino compound within the above range, the strength required for the cured product of the potting composition can be ensured. When a mixture of two or more polyfunctional amino compounds is used, the active hydrogen equivalent means the value of the mixture.

  Examples of the aliphatic polyamine include dimer acid derivatives such as dimer amine, dimer triamine and dimer polyamine, cardanol-modified polyamine, polycyclohexyl polyamine and the like. In the present disclosure, “aliphatic polyamine” means a polyamine in which an amino nitrogen is bonded to an aliphatic carbon, and includes alicyclic polyamines, aralkyl polyamines, and the like, and has an active hydrogen on the nitrogen atom of the amide group. Amidoamine is also included. Examples of the polyether polyamine include polyethylene glycol diamine, polypropylene glycol diamine, polytetramethylene glycol diamine, and polypropylene glycol triamine (for example, Jeffamine (manufactured by Huntsman)). By using an aliphatic polyamine, the moisture resistance of the potting composition can be further increased. Aliphatic polyamines having a C6-C30 chain alkyl moiety or a chain alkylene moiety, such as dimer amine, dimer triamine, and dimer polyamine, can be used particularly advantageously.

  In some embodiments, the multifunctional amino compound is about 2 wt% or more, about 5 wt% or more, or about 10 wt% or more, about 10 wt% or more based on the total weight of the organic components of the potting composition. It is contained in an amount of 30% by mass or less, about 20% by mass or less, or about 15% by mass or less.

  Non-reactive diluents are one of the important ingredients for obtaining the properties of the potting composition of the present disclosure. In general, an epoxy diluent used for adjusting the viscosity of a curable epoxy composition reacts during curing to generate a hydroxyl group derived from an epoxy group. Since the generated hydroxyl group increases the hydrophilicity of the cured product, the moisture resistance of the cured product may be reduced. According to the present disclosure, by using a non-reactive diluent, fluidity is imparted to the potting composition before curing, while reducing the generation of such unnecessary hydroxyl groups, and having excellent moisture resistance. A cured product can be obtained. Moreover, since a non-reactive diluent contributes also to low Tg of the hardened | cured material of a potting composition, a potting composition can contain an inorganic filler with a high filling rate. Non-reactive diluents are compounds that do not substantially react with glycidyl groups or amino groups under the curing conditions of the potting agent. As the non-reactive diluent, compounds having a flash point of about 250 ° C. or more among compounds known as plasticizers in the technical field of thermoplastic resins such as vinyl chloride resins can be used. Since the non-reactive diluent having a flash point of about 250 ° C. or higher has low volatility, it is possible to suppress changes in viscoelastic characteristics of the cured potting composition over time. In some embodiments, the flash point of the non-reactive diluent is about 260 ° C. or higher, or about 270 ° C. or higher, about 400 ° C. or lower, or about 350 ° C. or lower. A non-reactive diluent can be used individually or in combination of 2 or more types.

  Non-reactive diluents include, for example, paraffinic and naphthenic mineral oils; vegetable oils such as soybean oil, linseed oil and castor oil, and their modified halogenated, hydrogenated, oxidatively polymerized, maleated, etc. Epoxy-modified vegetable oils such as bean oil, epoxidized linseed oil, and epoxidized castor oil; dibasic acid esters such as azelaic acid alkyl ester and sebacic acid alkyl ester; glycerin fatty acid ester, polyglycerin fatty acid ester, trimethylolethane fatty acid ester, trimethylol Fatty acid esters of polyhydric alcohols such as propane fatty acid ester, pentaerythritol fatty acid ester, dipentaerythritol fatty acid ester; trimellitic acid ester, pyromellitic acid ester, biphenyltetracarboxylic acid ester, etc. Aromatic polycarboxylic acid ester; polybutadiene, polybutene, polyisobutylene, butadiene-acrylonitrile, polychloroprene, sebacic acid, azelaic acid, adipic acid, phthalic acid and other basic acids and ethylene glycol, propylene glycol, tetramethylene glycol, hexanediol , Octanediol, decanediol, dodecanediol, dimer acid diol, polyesters obtained from dihydric alcohols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polymer plasticizers such as poly (meth) acrylate. . Among these, vegetable oils, modified vegetable oils, epoxy-modified vegetable oils, and aromatic polycarboxylic acid esters are preferable because of their compatibility with potting compositions and the effect of lowering the Tg of cured products of potting compositions. In view of the above, trimellitic acid esters are particularly preferable, and in terms of sustainability, vegetable oils, modified vegetable oils, and epoxy-modified vegetable oils are particularly preferable.

  In addition, epoxy-modified vegetable oils such as epoxidized soybean oil, epoxidized flaxseed oil, and epoxidized castor oil react slowly with monofunctional phenolic compounds described below at high temperatures above the curing temperature, so monofunctional phenolic compounds at high temperatures Volatilization can be suppressed. Therefore, potting compositions containing these epoxy-modified vegetable oils as non-reactive diluents can be used particularly advantageously in terms of heat resistance and long-term stability.

  The aromatic polycarboxylic acid ester preferably has a linear or branched alkyl group at the ester site because of its excellent dispersibility and heat resistance in the potting composition. The carbon number of the alkyl group at the ester site of the aromatic polycarboxylic acid ester is generally 4 or more, 6 or more, or 8 or more, about 30 or less, about 24 or less, or about 20 or less. In the aromatic polycarboxylic acid ester, all carboxylic acids may be esterified or partial esters. All the alkyl groups at the ester site of the aromatic polycarboxylic acid ester may be the same or different from each other. The molecular weight of the aromatic polycarboxylic acid ester is not particularly limited, but is generally about 380 or more, about 500 or more, or about 600 or more, about 2000 or less, about 1500 or less, or about 1000 or less.

  Examples of trimellitic acid esters include tri- (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisooctyl trimellitate, tri-n-decyl trimellitate, triisodecyl trimellitate, carbon Examples include trimellitic acid mixed esters having an alkyl group of 4 to 30 at the ester site. Examples of pyromellitic acid esters include tetra- (2-ethylhexyl) pyromellitate, tetra-n-octyl pyromellitate, tetraisooctyl pyromellitate, tetra-n-decyl pyromellitate, tetraisodecyl pyromellitate, carbon Examples include pyromellitic acid mixed esters having an alkyl group of 4 to 30 at the ester site. Examples of biphenyl tetracarboxylic acid esters include 2,3,3 ′, 4′- or 3,4,3 ′, 4′-biphenyltetracarboxylic acid tetrabutyl ester, 2,3,3 ′, 4′- or 3 , 4,3 ′, 4′-biphenyltetracarboxylic acid tetrapentyl ester, 2,3,3 ′, 4′- or 3,4,3 ′, 4′-biphenyltetracarboxylic acid tetrahexyl ester, 2,3, 3 ', 4'- or 3,4,3', 4'-biphenyltetracarboxylic acid tetraheptyl ester, 2,3,3 ', 4'- or 3,4,3', 4'-biphenyltetracarboxylic acid Tetra (2-methylhexyl) ester, 2,3,3 ′, 4′- or 3,4,3 ′, 4′-biphenyltetracarboxylic acid tetra (n-octyl) ester, 2,3,3 ′, 4 '-Or 3, 4, 3' 4'-biphenyltetracarboxylic acid tetra (2-ethylhexyl) ester, 2,3,3 ', 4'- or 3,4,3', 4'-biphenyltetracarboxylic acid tetraisooctyl ester, 2,3,3 Examples include ', 4'- or 3,4,3', 4'-biphenyltetracarboxylic acid tetradecyl ester, and biphenyltetracarboxylic acid mixed ester having an alkyl group having 4 to 30 carbon atoms in the ester moiety.

  The number average molecular weight of the polymer plasticizer is, for example, about 500 or more, about 800 or more, or about 1000 or more, about 10,000 or less, about 8000 or less, or about 5000 or less. Fluidity can be imparted. The molecular weight distribution of the polymeric plasticizer is not particularly limited, but is generally less than about 3.5, less than about 2.5, or less than about 1.5.

  In some embodiments, the non-reactive diluent is about 5% or more, about 10% or more, or about 15% or more, about 15% or more by weight of the potting composition, based on the total weight of the organic components of the potting composition. It is contained in an amount of 50% by mass or less, about 45% by mass or less, or about 40% by mass or less. By using the non-reactive diluent within the above range, the potability of the potting composition can be further lowered while further improving the fluidity of the potting composition. The potting compositions according to these embodiments of the present disclosure are characterized by the use of greater amounts than using non-reactive diluents as plasticizers for thermoplastic resins.

  The monofunctional phenolic compound is a compound having one phenolic hydroxyl group and contributes to improving the brushing resistance of the potting composition while imparting fluidity to the potting composition like the non-reactive diluent. . Brushing (also called amine brushing) is a phenomenon in which the surface of the potting composition during or after curing reacts with the polyfunctional amino compound by carbon dioxide absorbed in the potting composition from the atmosphere. is there. Further, active hydrogen of the polyfunctional amino compound is consumed during brushing, and the curability and fluidity of the potting composition may be impaired. The flash point of the monofunctional phenolic compound is about 200 ° C. or higher. Since the monofunctional phenol compound having a flash point of about 200 ° C. or higher has low volatility, it is possible to suppress changes in viscoelastic characteristics of the cured potting composition over time. In some embodiments, the flash point of the monofunctional phenolic compound is about 210 ° C or higher, or about 220 ° C or higher, about 350 ° C or lower, or about 300 ° C or lower. A monofunctional phenol compound can be used individually or in combination of 2 or more types.

  The monofunctional phenol compound is preferably a highly hydrophobic compound containing no polar group such as a carbonyl group, a carboxyl group, a carboxylic acid group, or an amino group in addition to the phenolic hydroxyl group. Monofunctional phenolic compounds with high hydrophobicity, especially when combined with aliphatic polyamines as polyfunctional amino compounds, can lower the water absorption of the potting composition and increase the brushing resistance and the moisture resistance of the cured product. .

  Examples of the monofunctional phenol compound include octadecylphenol, cardanol, 3,4-dihydro-2,5,7,8-tetramethyl-2- (4,8, substituted with a substituted or unsubstituted long chain alkyl. 12-trimethyltridecyl) -2H-benzopyran-6-ol, 2,4-dimethyl-6- (1-methylpentadecyl) phenol, 4,6-bis (octylthiomethyl) -o-cresol, 4,6 -Bis (dodecylthiomethyl) -o-cresol, alkyl-3- (3,5-ditert-butyl-4-hydroxyphenyl) propionate, at least one of the 2-6 positions of substituted or unsubstituted phenol is substituted or Styrenated phenol substituted with unsubstituted 1-phenylethyl group (styrenyl group); substituted with phenylmethyl group (benzyl group) Etc. The benzylated phenol. The substituent on the phenolic aromatic ring of styrenated phenol and / or the aromatic ring of 1-phenylethyl group is preferably an alkyl group having 1 to 4 carbon atoms. Of these, styrenated phenol and cardanol can be advantageously used because they are easily available and highly hydrophobic. The number of substitutions of the 1-phenylethyl group of the styrenated phenol is generally 1 (mono-styrenated phenol), 2 (di-styrenated phenol) or 3 (tri-styrenated phenol), and in some embodiments the number of substitutions. Is 2 or 3. The styrenated phenol may be a mixture of two or more different numbers of 1-phenylethyl groups.

  In some embodiments, the monofunctional phenolic compound is about 5% or more, about 8% or more, or about 10% or more, about 10% or more by weight of the potting composition, based on the total weight of the organic components of the potting composition. It is contained in an amount of 40% by mass or less, about 35% by mass or less, or about 30% by mass or less. By using the monofunctional phenol compound within the above range, the brushing resistance of the potting composition can be further improved while further improving the fluidity of the potting composition.

  The non-reactive diluent and the monofunctional phenolic compound together add up to about 10% or more, about 15% or more, or about 20% or more by weight of the potting composition based on the total weight of the organic components of the potting composition. , About 55 mass% or less, about 50 mass% or less, or about 48 mass% or less. By setting the total amount of the non-reactive diluent and the monofunctional phenol compound in the above range, a cured product having a sufficient crosslinking density can be obtained while further improving the fluidity of the potting composition.

  The inorganic filler is a component that imparts strength and thermal conductivity to the potting composition. In general, inorganic fillers are not particularly limited because they have higher thermal conductivity than organic resins, but it is preferable to use inorganic compounds having excellent thermal conductivity. Examples of such inorganic compounds include aluminum hydroxide, alumina, and nitridation. Aluminum, boron nitride, silicon nitride, magnesium oxide and the like can be mentioned. Aluminum hydroxide, alumina, boron nitride and silicon nitride are preferred because they are excellent in thermal conductivity and moisture resistance, and among these, aluminum hydroxide is advantageously used because it is inexpensive and has excellent thermal conductivity.

  The shape of the inorganic filler is not particularly limited, but is preferably spherical when considering fluidity. The average particle size of the inorganic filler is, for example, about 0.05 μm or more, about 0.1 μm or more, or about 0.2 μm or more, about 100 μm or less, about 50 μm or less, or about 30 μm or less. As the inorganic filler, a filler having a single particle size distribution may be used, or two or more inorganic fillers having different particle size distributions may be used in combination in order to increase the filling rate of the inorganic filler. For example, by using the inorganic filler A having an average particle diameter of 8 μm and the inorganic filler B having an average particle diameter of 1 μm in combination, the gaps between the particles of the inorganic filler A can be filled with the inorganic filler B. The filling rate of the inorganic filler can be increased more than when A is used alone.

  In some embodiments, the inorganic filler is about 50% or more, about 52% or more, or about 55% or more, about 70% or less, about 70% or less of the potting composition, based on the total volume of the potting composition. 65 vol% or less, or about 60 vol% or less. The potting composition of these embodiments includes an inorganic filler at a high loading, so that the cured product can have a higher thermal conductivity. Since the thermal conductivity increases exponentially as the filling rate of the inorganic material increases, it is important to increase the filling rate. Inorganic fillers such as silica, kaolin, clay and calcium carbonate may be mixed with inorganic fillers having high thermal conductivity.

  The potting composition may contain a dispersant as required. The dispersant is used together with the inorganic filler in order to satisfactorily disperse the inorganic filler contained in one or both of the main agent and the curing agent. In order to increase the fluidity of the potting composition, a dispersant that does not impart thixotropic properties to the composition, that is, has a thinning effect, can be advantageously used. In general, it is considered that the dispersing agent is partially adsorbed on the particle surface of the inorganic filler and is stabilized without agglomerating the particles by 1) electrical repulsion between the particles and 2) steric repulsion. Dispersants are classified into low molecular compounds such as surfactants and coupling agents, and high molecular compounds having various functional groups. Examples of functional groups for adsorbing the dispersant on the particle surface of the inorganic filler include sulfonic acid groups, phosphoric acid groups, carboxylic acid groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, amide groups, ester groups, ether groups, and the like. Can be mentioned.

  Specifically, surfactant type dispersants include stearic acid, isostearic acid, dodecylbenzenesulfonic acid, Neogen series, Neocor series, Prisurf series, Sorgen series, Kao manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Examples include the Leidol series, Exel series, and the Tyrazole series manufactured by Taiyo Kagaku. Coupling agent types include Shin-Etsu Chemical Co., Ltd. silane coupling agent KBM series, KBE series, Momentive Performance Materials silane coupling agent SILQUEST Silanes series, Evonik silane coupling agent dyna Examples include the silane series, titanate manufactured by Ajinomoto Fine Techno Co., Ltd., and the aluminate coupling agent Plenact series. The polymer compound type dispersants include the DISPERBYK series manufactured by Big Chemie, the DISPARLON series manufactured by Enomoto Kasei Co., Ltd., the Floren series manufactured by Kyoeisha Chemical Co., Ltd., the AgriSperse series manufactured by New Century Coatings Co., Ltd., and NOF Corporation And the Mariarim series.

  A dispersing agent can be used individually or in combination of 2 or more types. Generally, the dispersant is about 0.1 parts by mass or more, about 0.2 parts by mass or more, or about 0.5 parts by mass or more, about 10 parts by mass or less, about 5 parts by mass or less with respect to 100 parts by mass of the inorganic filler. Alternatively, it can be used in an amount of about 2 parts by mass or less.

  The potting composition may contain a reactive diluent, such as a reactive epoxy diluent, a reactive amine diluent, as required. The reactive epoxy diluent is included in the main agent, and the reactive amine diluent is included in the curing agent. Examples of the reactive epoxy diluent include n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, alkyl glycidyl ether having 12 to 18 carbon atoms, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, nonylphenyl glycidyl ether, carda Monofunctional glycidyl ether such as norglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, resorcinol diglycidyl ether, etc. And trifunctional glycidyl ethers such as trimethylolpropane triglycidyl etherExamples of the reactive amine diluent include 2-ethylhexylamine, octylamine, dodecylamine, octadecylamine, oleylamine, cocoalkylamine having 8 to 20 carbon atoms, tallow alkylamine having 12 to 22 carbon atoms, and N-cocoalkyl-1 , 3-diaminopropane, polypropylene glycol monoamine (for example, Jeffamine M-600, M-1000, M-2005, M-2070 (manufactured by Huntsman)). Reactive diluents also impart fluidity to the potting composition. A reactive diluent can be used individually or in combination of 2 or more types, for example, a reactive epoxy diluent and a reactive amine diluent can also be used in combination. The reactive diluent may generally be included in the potting composition in an amount of about 30 wt% or less, about 25 wt% or less, or about 20 wt% or less, based on the total weight of the organic components of the potting composition. If the amount added is too large, the monofunctional diluent may reduce the heat resistance of the cured product of the potting composition, and the multifunctional diluent may increase the crosslink density of the cured product of the potting composition to increase flexibility. May not provide a cured product.

  The potting composition includes additives such as coupling agents such as modified silanes and organic titanates, colorants such as carbon black, leveling agents, antioxidants, metal deactivators, and flame retardants as necessary. But you can. These additives can be included in one or both of the main agent and the curing agent.

  The number of active hydrogens in the polyfunctional amino compound and optional reactive amine diluent relative to the number of epoxy groups in the polyfunctional epoxy resin and optional reactive epoxy diluent in the potting composition is about Advantageously, it is 0.6 or more, or about 0.8 or more, about 1.2 or less, or about 1.1 or less. By setting it as the said range, high intensity | strength can be provided to the hardened | cured material of a potting composition.

  The preparation method of the main agent and the curing agent of the potting composition is not particularly limited, and the main agent and the curing agent components are each a mixer such as a pot mill, a rotation and revolution stirrer, a three roll mill, a rotary mixer, a twin screw mixer, a disper, etc. It can be prepared by putting in and mixing. You may heat at the time of mixing, and you may perform a defoaming process after mixing as needed.

  Since the potting composition of the present disclosure is a two-component potting composition comprising a main agent and a curing agent, the main agent and the curing agent are mixed at the time of use. The mixing method of the main agent and the curing agent is not particularly limited, and the main agent and the curing agent can be charged and mixed in a mixer such as a rotation / revolution stirrer, a rotary mixer, a twin screw mixer, or a disper. You may perform a defoaming process after mixing as needed. It is also possible to mix the main agent and the curing agent in the dispenser through a metering valve and pot it from the dispenser.

In some embodiments, the pre-curing viscosity (initial viscosity) of the mixture of base agent and curing agent is no greater than about 50 Pa · s, no greater than about 40 Pa · s, as measured at a temperature of 25 ° C. and a shear rate of 200 s ⁻¹ , or About 30 Pa · s or less. The viscosity is a value measured at 25 ° C. using a rotational viscometer using a shear rate of 200 s ⁻¹ and a cone plate of 1 ° as a probe. By determining the composition of each component so that the viscosity of the mixture falls within the above range, the flowability of the potting composition can be made particularly suitable for potting applications.

  The mixed potting composition is poured, for example, so as to cover the whole or around the object placed in the container or on the substrate, or to fill the space below the object. The potting composition is then cured by standing at room temperature or heating, for example by heating at about 50 to about 200 ° C. for about 1 minute to about 10 hours.

  The Tg of the cured product of the potting composition is, for example, about −10 ° C. or lower, about −15 ° C. or lower, or about −20 ° C. or lower. The Tg of the cured product is 3.5 Hz in length, 0.5 cm in width, and 1 mm in thickness on a cured product strip using a dynamic viscoelasticity measuring device in a tension mode with a frequency of 1 Hz and a heating rate of 5 ° C./min. It is defined as a peak temperature when tan δ defined as storage elastic modulus E ′ / loss elastic modulus E ″ is plotted while applying a stress at a temperature. A cured product having such a low Tg has a wide range from a low temperature to a high temperature. Since stress can be relaxed in a temperature range (for example, −40 ° C. to 100 ° C.), cracking of the cured product itself, peeling of the cured product from the container, and the like are prevented, and the object in the container is not damaged.

  The thermal conductivity of the cured material of the potting composition varies depending on the type of inorganic filler used and the filling amount. In some embodiments where the inorganic filler includes aluminum hydroxide, the cured product of the potting composition has a thermal conductivity of about 1 W / m · K or more, about 1.1 W / m · K or more, or about 1.2 W / m · K or more. The thermal conductivity of the cured product is a value measured according to the hot wire method using a thermal conductivity meter for a block of a cured product of 20 mm × 75 mm × 150 mm. Since the potting composition of the present disclosure can increase the filling amount of the inorganic filler even when aluminum hydroxide having a lower thermal conductivity than boron nitride or the like is used, the cured product has a high thermal conductivity. Can be granted.

In some embodiments, the cured potting composition has a low hardness and / or a high volume resistivity. The hardness of the cured product of the potting composition is, for example, about 90 or less, about 70 or less, or about 40 or less when measured with a Shore A durometer on a small piece of the cured product having a diameter of 4 cm and a thickness of 8 mm. The volume resistivity of the cured product of the potting composition is, for example, about 1 × 10 ⁸ Ω · cm or more when measured using a superinsulator equipped with a plate sample electrode for a cured product having a 10 cm square and a thickness of 1 mm. , About 1 × 10 ⁹ Ω · cm or more, or about 1 × 10 ¹¹ Ω · cm or more. A cured product having a high volume resistivity can be suitably used for potting applications that require insulation.

  The two-part potting composition of the present disclosure can be suitably used for potting applications that require thermal conductivity, for example, battery units of electric vehicles and plug-in hybrid vehicles.

  In the following examples, specific embodiments of the present disclosure are illustrated, but the present invention is not limited thereto. All parts and percentages are by weight unless otherwise specified.

  The materials used as components of the potting composition in this example are shown in Table 1 below.

<Test method>
(1) Viscosity The viscosity (initial viscosity) of the mixed composition is measured at 25 ° C. using a viscometer rheostress (manufactured by Haake Medingen GmbH) using a cone plate 1 ° as a probe at a shear rate of 200 s ⁻¹ .

(2) Thermal conductivity A block of a cured product having a size of 20 mm × 75 mm × 150 mm is prepared. The thermal conductivity is measured according to a hot wire method using a thermal conductivity meter Chemtherm QTM-D3 (manufactured by Kyoto Electronics Industry Co., Ltd.).

(3) Viscoelastic properties A cured product strip having a length of 3.5 cm, a width of 0.5 cm, and a thickness of 1 mm is prepared. Using a dynamic viscoelasticity measuring device RSA-III (manufactured by Rheometric Scientific), the cured product was stressed in tension mode at a frequency of 1 Hz and a heating rate of 5 ° C./min. The tan δ defined as “is plotted, and the peak temperature is defined as Tg of the cured product. The Tg is desirably −10 ° C. or lower. The storage elastic modulus at −20 ° C. is shown in Table 3.

(4) Shore A hardness A small piece of a cured product having a diameter of 4 cm and a thickness of 8 mm is prepared. The hardness is measured using a Shore A durometer hardness meter (manufactured by Kobunshi Keiki Co., Ltd.). The Shore A hardness is desirably 90 or less.

(5) Volume resistivity A cured sheet having a 10 cm square and a thickness of 1 mm is prepared. The volume resistivity is measured using a superinsulator SM-8220 (manufactured by Hioki Electric Co., Ltd.) equipped with a plate sample electrode SME-8310. The volume resistivity is desirably at least 1 × 10 ⁹ Ω · cm.

(6) Moist heat resistance Prepare a small piece of a cured product having a diameter of 4 cm and a thickness of 8 mm. The small piece is left in a constant temperature and humidity oven at 85 ° C. and a relative humidity of 85% and taken out after 1000 hours. After standing at room temperature for 24 hours, it is immersed in methyl ethyl ketone, and changes after 24 hours are recorded at the following three levels. A: No change in the cured product. B: Methyl ethyl ketone solvent was dirty. C: The cured product was dissolved.

(7) Heat resistance A small piece of a cured product having a diameter of 4 cm and a thickness of 8 mm is prepared. The small piece is left in a constant temperature oven at 130 ° C. and taken out after 1000 hours. After standing at room temperature for 24 hours, it is immersed in methyl ethyl ketone, and changes after 24 hours are recorded at the following three levels. A: No change in the cured product. B: Methyl ethyl ketone solvent was dirty. C: The cured product was dissolved.

<Preparation of potting composition>
<Example 1>
The main agent was prepared by the following procedure. EP4005 10.5 g, ED503 1.5 g, N-08 4.5 g and Disperbyk-111 0.9 g were mixed well in a plastic container. Next, aluminum hydroxide (30.0 g of BF013 and 60.0 g of BF083) was added to the container and mixed.

  A curing agent was prepared by the following procedure. Priamine 1071 2.4 g, Famine O 2.4 g, SP-24 6.0 g and N-08 2.7 g were mixed in a plastic container. A tan liquid was obtained.

  The cured product was prepared by the following procedure. The main agent and the curing agent were mixed at 2000 rpm for 2 minutes using a rotation and revolution stirrer, and deaerated for 1.5 minutes. The mixture was poured into a mold of the shape for measuring each property. For example, the sheet sample was prepared by the following procedure. The mixture is poured onto a liner paper on which a PTFE sheet spacer having a thickness of 1 mm is placed and covered with another liner paper to form a stack. The stack is placed between upper and lower platens of a hot press machine at 105 ° C., 2 ° C. Pressure was applied for a time, and the liner paper was removed to obtain a sheet sample. Table 2 shows the composition of the potting composition, and Table 3 shows the properties of the cured product.

<Examples 2 to 16 and Comparative Examples 1 and 2>
A potting composition was prepared in the same manner as in Example 1 except that the composition was as shown in Table 2. Table 3 shows the properties of the cured product. When the cured product of Comparative Example 1 using a monofunctional phenol compound having a low flash point was allowed to stand at a high temperature (130 ° C.), the monofunctional phenol compound was gradually volatilized and the hardness increased with time.

Claims (7)

A polyfunctional epoxy resin having an epoxy equivalent of 300 g / mol or more,
A non-reactive diluent with a flash point of 250 ° C. or higher,
A polyfunctional amino compound having an active hydrogen equivalent of 100 g / mol or more,
A two-component potting composition comprising a main component and a curing agent, comprising a monofunctional phenolic compound having a flash point of 200 ° C. or higher, and an inorganic filler,
A two-component potting composition in which the polyfunctional epoxy resin is contained in a main agent and the polyfunctional amino compound is contained in a curing agent.   The two-component potting composition contains the non-reactive diluent and the monofunctional phenolic compound in an amount of 10 to 50% by mass based on the total mass of the organic components of the two-component potting composition. The two-component potting composition according to claim 1.   The two-component potting composition according to any one of claims 1 and 2, wherein the two-component potting composition contains 50% by volume to 70% by volume of the inorganic filler based on a total volume of the two-component potting composition. Composition.   The two-component mold according to any one of claims 1 to 3, wherein the cured product of the two-component potting composition has a thermal conductivity of 1 W / m · K or more, and the inorganic filler contains aluminum hydroxide. Potting composition.   The two-component potting composition according to any one of claims 1 to 4, wherein the polyfunctional amino compound is an aliphatic polyamine, and the monofunctional phenol compound is styrenated phenol or cardanol.   The two-component potting composition according to any one of claims 1 to 5, wherein the non-reactive diluent is an epoxy-modified vegetable oil. The two-component potting according to any one of claims 1 to 6, wherein the viscosity of the mixture of the main agent and the curing agent when measured at a temperature of 25 ° C and a shear rate of 200 s ^-1 is 50 Pa · s or less. Composition.