JP5946574B1 - Polyurethane resin composition - Google Patents

Abstract

An object of the present invention is to provide a polyurethane resin composition exhibiting excellent elongation (flexibility) and excellent compatibility, hardness, moisture resistance and flame retardancy. A polyurethane resin composition comprising a hydroxyl group-containing compound, a polyisocyanate compound, a plasticizer and an inorganic filler, wherein the hydroxyl group-containing compound is a dimer acid polyol, and the content of the inorganic filler is: The polyurethane resin composition which is 50 to 85% by weight in the polyurethane resin composition. [Selection figure] None

Description

  The present invention relates to a polyurethane resin composition.

  Polyurethane resins are used for electrically insulating sealing materials and the like because of their good flexibility, wear resistance, low temperature curability, electrical properties, and the like.

  This polyurethane resin can protect electrical and electronic parts from moisture, dust-containing atmosphere, vibration, impact, and the like.

  In addition to the electrical insulating sealing material, polyurethane resins are widely used as coating agents, adhesives, and the like in various fields such as electricity, electronics, automobiles, civil engineering, and architecture.

  When such polyurethane-based resins are used in the various fields described above, the selection of the polyol component is important, and various studies have been conducted.

  For example, a polyurethane-based resin composition containing a polybutadiene polyol as a polyol component has been reported. Japanese Patent No. 5568187 (Patent Document 1) describes wet heat resistance, flame resistance, electrical insulation, and workability. A polyurethane resin composition that is excellent and hardly causes chemical stress cracks in a housing such as an electronic substrate or a resin case is disclosed. A chemical stress crack is a typical brittle fracture that occurs with a tensile stress that is less than the tensile strength of the resin case. The chemical adheres to or comes into contact with the part where the tensile stress occurs (the part where the load is applied) in the molded product. In this case, it refers to a phenomenon in which cracks occur due to a synergistic effect between chemicals and stress.

  On the other hand, an inorganic filler is added to the polyurethane resin composition in order to improve heat resistance and heat dissipation (Patent Document 2).

Japanese Patent No. 5568187 JP 2011-001426 A

  Therefore, when an inorganic filler is blended in the polyurethane resin composition described in Patent Document 1, the elongation rate (flexibility) of the polyurethane resin is insufficient, and the polyurethane resin is cast and molded on an electronic substrate. When the heat cycle test was performed, the problem was that the resin case cracked or peeled off.

  An object of this invention is to provide the polyurethane resin composition which shows the outstanding elongation rate (flexibility), and shows the outstanding compatibility, hardness, moisture resistance, and a flame retardance.

  In view of the above problems, the present inventors conducted extensive research. As a result, a polyurethane resin composition containing a hydroxyl group-containing compound, a polyisocyanate compound, a plasticizer, and an inorganic filler, wherein the hydroxyl group-containing compound is a dimer acid polyol and the content of the inorganic filler is polyurethane. It has been found that the above object can be achieved if the polyurethane resin composition is 50 to 85% by weight in the resin composition. Further research based on this knowledge has led to the completion of the present invention.

That is, this invention provides the following polyurethane resin compositions, sealing materials, and electrical and electronic parts.
Item 1. A polyurethane resin composition comprising a hydroxyl group-containing compound, a polyisocyanate compound, a plasticizer and an inorganic filler,
The polyurethane resin composition, wherein the hydroxyl group-containing compound is a dimer acid polyol, and the content of the inorganic filler is 50 to 85% by weight in the polyurethane resin composition.
Item 2.
Item 2. The polyurethane resin composition according to Item 1, wherein the hydroxyl group-containing compound comprises a castor oil-based polyol together with the dimer acid polyol.
Item 3.
Item 3. The polyurethane resin composition according to Item 2, wherein the content ratio of the dimer acid polyol and the castor oil-based polyol is the former: the latter = 20: 80 to 80:20 in a weight ratio.
Item 4.
Item 4. The polyurethane resin composition according to any one of Items 1 to 3, wherein the polyisocyanate compound is an isocyanurate-modified product of hexamethylene diisocyanate.
Item 5.
Item 5. The polyurethane resin composition according to any one of Items 1 to 4, which is used for sealing electric and electronic parts.
Item 6.
Item 6. A sealing material comprising the polyurethane resin composition according to any one of Items 1 to 5.
Item 7.
Item 7. An electrical and electronic component sealed with a resin using the sealing material according to Item 6.

  An object of the polyurethane resin composition of the present invention is to provide a polyurethane resin composition that exhibits excellent elongation (flexibility) and exhibits excellent compatibility, hardness, moisture resistance, and flame retardancy. The polyurethane resin composition of the present invention can be suitably used for, for example, insulation treatment of various electric and electronic parts. Moreover, since the sealing material of this invention contains the said polyurethane resin composition, it is excellent in elongation rate (flexibility), compatibility, hardness, moisture resistance, and a flame retardance. Furthermore, since the electrical / electronic component of the present invention is resin-sealed using the sealing material, it exhibits high reliability.

  The polyurethane resin composition, sealing material and electric / electronic component of the present invention will be described in detail below. In this specification, the expression “containing” or “including” includes the concepts of “containing”, “including”, “consisting essentially of”, and “consisting only of”.

1. Polyurethane resin composition The polyurethane resin composition of the present invention is a polyurethane resin composition comprising a hydroxyl group-containing compound, a polyisocyanate compound, a plasticizer and an inorganic filler, wherein the hydroxyl group-containing compound is a dimer acid polyol, and It is a polyurethane resin composition whose content of this inorganic filler is 50 to 85 weight% in a polyurethane resin composition.

1-1. Hydroxyl-containing compound The hydroxyl-containing compound (A) used in the present invention contains a dimer acid polyol (A1).

1-1-1. Dimer acid polyol (A1)
Examples of the dimer acid polyol (A1) used in the present invention include the following reaction products (1) to (4) or a mixture thereof.
(1) a reaction product of a dimer acid and a short-chain diol (dihydric alcohol), triol (trihydric alcohol) or short-chain polyol (tetrahydric or higher alcohol);
(2) reaction product of dimer acid and polyalkylene glycol, polyalkylene triol or long-chain polyol;
(3) a reaction product obtained by reacting the short-chain diol, triol, or polyol with a mixture of dimer acid and other polycarboxylic acid such as adipic acid, and (4) dimer acid and alkylene oxide. Reaction product with (for example, ethylene oxide, propylene oxide, etc.) The above dimer acid is a dibasic acid, and two monobasic fatty chains (usually 18 carbon atoms) are bonded by a carbon-carbon covalent bond. This refers to a dibasic acid having a double molecular weight obtained by bonding two molecules. The typical compound is a dimer obtained by polymerization of unsaturated fatty acids such as linoleic acid, oleic acid, elaidic acid, tall oil fatty acid and the like. Generally, since the unsaturated fatty acid having 18 carbon atoms is used as a raw material, the main component is a dicarboxylic acid having 36 carbon atoms. The dimer acid may contain a trimer and / or a monomer.

  Examples of the short-chain diol include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol 2,2,4-trimethyl-1,5-pentanediol, 2-ethyl-2-butylpropanediol, 1,9-nonanediol, 2-methyloctanediol, 1,10-decanediol, etc. To 10 diols.

  Examples of the triol include triols having 3 to 10 carbon atoms such as glycerin and trimethylolpropane (TMP).

  Examples of the short-chain polyol include polyols having 3 to 10 carbon atoms such as tetramethylolmethane and pentaerythritol.

  Examples of the polyalkylene glycol include polyalkylene glycol having 10 to 500 carbon atoms such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and ethylene glycol-propylene glycol copolymer.

  Examples of the polyalkylene triol include C10-500 polyalkylene triols such as polypropylene oxide triol, polyethylene oxide triol, polypropylene oxide / polyethylene oxide copolymer triol, and the like.

  Examples of the long-chain polyol include a polyol having 11 to 500 carbon atoms such as polypropylene glycol.

  The weight average molecular weight (Mw) of the dimer acid polyol is usually in the range of 300 to 50000, preferably in the range of 300 to 10000, more preferably in the range of 300 to 3000.

  The dimer acid polyol (A1) has an average number of functional groups per molecule of 2 to 4 (preferably 2 to 3), and a hydroxyl value of 2 to 10000 mgKOH / g, preferably 30 to 500 mgKOH / g. Is more preferable, and it is further more preferable that it is 30-300.

  A commercial item can be used for dimer acid polyol (A1). As the dimer acid polyol (A1), for example, Pripol 2033-LQ- (GD) (average hydroxyl value: 202 to 212 mgKOH / g, average functional group number: 2) manufactured by Croda Japan Co., Ltd., manufactured by Hitachi Chemical Co., Ltd. TA22-558 (hydroxyl value: 70 to 75 mgKOH / g, average functional group number: 3), TA22-559 (hydroxyl value: 78 to 82 mgKOH / g, average functional group number: 3), EDITION E-404 manufactured by Kao Corporation ( Hydroxyl value: 120 mgKOH / g, average functional group number: 3) and the like.

  There is no restriction | limiting in particular in content of a dimer acid polyol (A1), It is preferable that it is 0.01-40 weight% with respect to 100 weight% of polyurethane resin compositions especially, and is 0.1-30 weight%. More preferably, the content is 1 to 25% by weight.

  The said dimer acid polyol (A1) can be used individually by 1 type, or 2 or more types can also be mixed and used for it.

  In addition to the dimer acid polyol (A1), the hydroxyl group-containing compound (A) used in the present invention can further contain a castor oil-based polyol (A2).

1-1-2. Castor oil-based polyol (A2)
Examples of the castor oil-based polyol (A2) used in the present invention include castor oil and castor oil derivatives.

  Examples of the castor oil derivative include castor oil fatty acid; hydrogenated castor oil hydrogenated to castor oil or castor oil fatty acid; transesterification product of castor oil and other fats and oils; reaction product of castor oil and polyhydric alcohol; An esterification reaction product of a castor oil fatty acid and a polyhydric alcohol; those obtained by addition polymerization of an alkylene oxide, and the like. Among the above castor oil-based polyols, it is preferable to use castor oil.

  The castor oil-based polyol used in the present invention may be a hydrogenated castor oil-based polyol. Examples of the hydrogenated castor oil-based polyol include those disclosed in JP-A-2-298574. The hydrogenated castor oil-based polyol can be obtained by hydrogenation of the aforementioned castor oil-based polyol.

  The number average molecular weight (Mn) of the castor oil-based polyol (A2) is usually in the range of 100 to 4,000, preferably in the range of 300 to 2,500.

  The castor oil-based polyol (A2) has an average hydroxyl value determined according to JIS K1557-1 of preferably 20 to 250 mgKOH / g, and more preferably 50 to 120 mgKOH / g.

  In the present specification, the number average molecular weight (Mn) and the weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the number average molecular weight and the weight average molecular weight determined by the GPC method are as follows: Shodex GPC System 21 manufactured by Showa Denko KK as a measuring device and Shodex LF-804 / KF-803 / manufactured by Showa Denko KK as a column. KF-804 can be measured using NMP as the mobile phase at a column temperature of 40 ° C. and calculated using a standard polystyrene calibration curve.

  The content of the castor oil-based polyol (A2) is not particularly limited, and is preferably 0.01 to 40% by weight, more preferably 0.1 to 30% by weight with respect to 100% by weight of the polyurethane resin composition. More preferably, it is 1 to 25% by weight.

  The castor oil-based polyol (A2) can be used alone or in combination of two or more.

  The polyurethane resin composition of the present invention preferably contains a dimer acid polyol (A1) and a castor oil-based polyol (A2) as a hydroxyl group-containing compound, whereby the compatibility when mixing the polyurethane resin composition is improved. Excellent and effective in suppressing bleed out.

  When the dimer acid polyol (A1) and the castor oil-based polyol (A2) are contained as the hydroxyl group-containing compound, the content ratio is not particularly limited, and is, for example, 10:90 to 90:10 (weight ratio). It is preferable that the ratio is 20:80 to 80:20 (weight ratio).

  The hydroxyl group-containing compound used in the present invention can contain a hydroxyl group-containing compound (A3) other than the dimer acid polyol (A1) and the castor oil-based polyol (A2) to such an extent that the effects of the present invention are not impaired. Examples of the hydroxyl group-containing compound (A3) include polydiene polyols such as polybutadiene polyol and polyisoprene polyol; polyether polyols; polyester polyols; polycarbonate polyols; polycaprolactone polyols; hydrides thereof (for example, hydrides of polybutadiene polyols). Hydrides of polydiene polyols such as hydrides of polyisoprene polyol; hydrides of castor oil, etc.).

  Examples of the polydiene polyol include polybutadiene polyol [NISSO-PBG series manufactured by Nippon Soda Co., Ltd. (G-1000, G-2000, G-3000, etc.), “Poly Bd series” (R-45M, manufactured by ARCO, USA). , R-45HT, CS-15, CN-15, etc.)] and polyisoprene polyol [“Poly ip” manufactured by Idemitsu Kosan Co., Ltd.] and the like.

  Examples of the hydride of polydiene polyol include, for example, hydride of polybutadiene polyol [NISO-PBGI series (GI-1000, GI-2000, GI-3000, etc.) manufactured by Nippon Soda Co., Ltd.], hydrogen of polyisoprene polyol. And chemicals [“Epol” manufactured by Idemitsu Kosan Co., Ltd.].

  Examples of polyether polyols include water, low molecular weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcin, hydroquinone, etc.), etc. And polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

  The polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

  Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 2-butyl-2-ethyl-1. , 3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl Examples include -1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol.

  Examples of the acid component include succinic acid, methyl succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid , And these acid anhydrides.

  Examples of the polycarbonate polyol include a polycarbonate polyol obtained by polycondensation reaction of the polyol component and phosgene; the polyol component, dimethyl carbonate, diethyl carbonate, diprovir carbonate, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, ethylene carbonate, Polycarbonate polyol obtained by ester exchange condensation with carbonic acid diesters such as propylene carbonate, diphenyl carbonate and dibenzyl carbonate; copolymerized polycarbonate polyol obtained by using two or more of the above polyol components in combination; Polycarbonate polyol obtained by esterification reaction with a compound; the above-mentioned various polycarbonate polyols and a hydroxyl group-containing compound A polycarbonate polyol obtained by a reaction of tellurization; a polycarbonate polyol obtained by a transesterification reaction between the above various polycarbonate polyols and an ester compound; a polycarbonate polyol obtained by a transesterification reaction between the various polycarbonate polyols and a hydroxyl group-containing compound; And polyester polycarbonate polyols obtained by polycondensation reaction of the various polycarbonate polyols and dicarboxylic acid compounds; copolymer polyether polycarbonate polyols obtained by copolymerizing the various polycarbonate polyols and alkylene oxides; and the like.

  Examples of the polycaprolactone polyol include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and δ-valerolactone.

  The said hydroxyl-containing compound (A3) can be used individually by 1 type, or 2 or more types can also be mixed and used for it.

  In the case of containing the hydroxyl group-containing compound (A3), the content is not particularly limited, and is preferably 1 to 20% by weight, more preferably 1 to 15% by weight with respect to 100% by weight of the polyurethane resin composition. More preferably, it is 1 to 10% by weight.

1-2. Polyisocyanate compound (B)
The polyisocyanate compound (B) used in the present invention is not particularly limited, and examples thereof include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic polyisocyanate compounds, and araliphatic polyisocyanate compounds.

  Examples of the aliphatic polyisocyanate compound include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2-methyl. Examples include pentane-1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate.

  Examples of the alicyclic polyisocyanate compound include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, and 1,3-bis (isocyanate methyl). And cyclohexane.

  Examples of the aromatic polyisocyanate compound include tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and the like can be mentioned.

  Examples of the araliphatic polyisocyanate compound include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and α, α, α, α-tetramethylxylylene diisocyanate.

  Especially, as a polyisocyanate compound used for this invention, it is preferable to contain the isocyanurate modified body (B1) of a polyisocyanate compound. When the polyisocyanate compound contains the isocyanurate-modified product (B1) of the polyisocyanate compound, the polyurethane resin composition has excellent heat resistance and moisture resistance.

  Examples of such isocyanurate-modified products (B1) of polyisocyanate compounds include the above-mentioned isocyanurate-modified products of aliphatic polyisocyanate compounds, isocyanurate-modified products of alicyclic polyisocyanate compounds, and isocyanurates of aromatic polyisocyanate compounds. Examples include modified products and araliphatic polyisocyanate compounds. Among these, a preferable isocyanurate-modified product (B1) of a polyisocyanate compound is an isocyanurate-modified product of an alicyclic polyisocyanate compound, more preferably an isocyanurate-modified product of hexamethylene diisocyanate or diphenylmethane diisocyanate.

  As a commercial item of the isocyanate group containing compound containing the isocyanurate modified body (B1) of a polyisocyanate compound, for example, Duranate TLA-100 (manufactured by HDI-based isocyanurate Asahi Kasei Chemicals), Coronate HX (HDI-based isocyanurate Nippon Polyurethane Co., Ltd.) Manufactured) and the like.

  The said isocyanate group containing compound can be used individually by 1 type, or can also mix and use 2 or more types.

  The polyisocyanate compound may contain other polyisocyanate compound (B2) in addition to the isocyanurate-modified product of the polyisocyanate compound.

  Examples of other polyisocyanate compounds (B2) include allophanate-modified products of the above-mentioned aliphatic polyisocyanate compounds, allophanate-modified products of alicyclic polyisocyanate compounds, allophanate-modified products of aromatic polyisocyanate compounds, and araliphatic poly Examples include allophanate-modified products of isocyanate compounds.

  In the polyurethane resin composition of the present invention, the content of the polyisocyanate compound (B) used is not particularly limited, and is preferably 0.1 to 30% by weight with respect to 100% by weight of the polyurethane resin composition. -20% by weight is more preferred. In the polyurethane resin composition of the present invention, the NCO / OH ratio between the isocyanate group-containing compound and the hydroxyl group-containing compound is preferably 0.6 to 2.0, and preferably 0.7 to 1.5. It is more preferable.

1-3. Plasticizer (C)
Examples of the plasticizer (C) used in the present invention include phthalic acid esters such as dioctyl phthalate, diisononyl phthalate (diisononyl phthalate) and diundecyl phthalate; adipates such as dioctyl adipate and diisononyl adipate; Castor oil-based esters such as butylacetylricinoleate, acetylated ricinoleic acid triglyceride, and acetylated polyricinoleic acid triglyceride; trimellitic esters such as trioctyl trimellitate and triisononyl trimellitate; tetraoctyl pyromellitate, tetra Examples include pyromellitic acid esters such as isononyl pyromellitate. Among these, diisononyl phthalate is preferable.

  There is no restriction | limiting in particular as content of a plasticizer (C), Especially it is preferable that it is 0.1-50 weight% with respect to 100 weight% of polyurethane resin compositions, and it is more preferable that it is 5-30 weight%. preferable.

  The said plasticizer (C) can be used individually by 1 type, or 2 or more types can also be mixed and used for it.

1-4. Inorganic filler (D)
The inorganic filler (D) used in the present invention is not particularly limited, and examples thereof include metal hydroxide, metal oxide, metal nitride, and zeolite.

  Examples of the metal hydroxide include aluminum hydroxide and magnesium hydroxide.

  Examples of the metal oxide include aluminum oxide (alumina), magnesium oxide, silicon oxide (silica and the like), titanium oxide and the like.

  Examples of the metal nitride include boron nitride, aluminum nitride, silicon nitride, and the like.

  The zeolite is not particularly limited, and various types of zeolite used in the polyurethane resin composition can be used.

  As the zeolite, for example, an alkali metal or alkaline earth metal crystalline hydrous aluminosilicate is preferable.

  The crystal form of zeolite is not particularly limited, and examples include A type, X type, and LSX type. Among these, A type is preferable.

  The alkali metal or alkaline earth metal in the zeolite is not particularly limited, and examples thereof include potassium, sodium, calcium, and lithium. Among these, potassium is preferable.

  Preferred inorganic fillers are metal hydroxides and metal oxides, more preferably aluminum hydroxide and alumina, and particularly preferably aluminum hydroxide.

  The said inorganic filler (D) can be used individually by 1 type, or 2 or more types can also be mixed and used for it. In particular, it is preferable to mix two or more inorganic fillers, and it is more preferable to mix two or more inorganic fillers having different average particle diameters.

  The content of the inorganic filler (D) is 50 to 85% by weight in the polyurethane resin composition, and when it is less than 50% by weight, the flame retardancy of the polyurethane resin composition is deteriorated and 85% by weight is reduced. When exceeding, a uniform hardened | cured material cannot be produced from a polyurethane resin composition.

  Especially, 55-80 weight% is preferable with respect to 100 weight% of polyurethane resin compositions, and, as for content of an inorganic filler (D), 60-79 weight% is more preferable.

  The average particle diameter of the inorganic filler (D) is not particularly limited, and examples thereof include an inorganic filler of 1 to 45 μm. In the present invention, when two or more kinds of inorganic fillers having different average particle diameters are contained, as the inorganic filler, an inorganic filler (D1) having an average particle diameter of 5 to 45 μm and an average particle diameter of less than 5 μm It is preferable to contain an inorganic filler (D2).

  The inorganic filler (D1) having an average particle diameter of 5 to 45 μm is preferably an inorganic filler having an average particle diameter of 5 to 30 μm, and more preferably an inorganic filler having an average particle diameter of 8 to 27 μm.

  The inorganic filler (D2) having an average particle diameter of less than 5 μm is preferably an inorganic filler having an average particle diameter of 3 μm or less, more preferably an inorganic filler having an average particle diameter of 2 μm or less, and more preferably an average An inorganic filler having a particle size of 1 μm or less.

Here, the average particle diameter means a particle diameter at a volume-based cumulative 50% in a particle size distribution measured by a laser diffraction / scattering method, that is, D ₅₀ (median diameter).

The volume-based cumulative 50% particle size (D ₅₀ ) is a particle size at which the cumulative value is 50% in a cumulative curve obtained by obtaining a particle size distribution on a volume basis and setting the total volume to 100%.

Similarly, the 10% particle size (D ₁₀ ) and the 90% particle size (D ₉₀ ) are a volume-based cumulative 10% particle size and a volume-based cumulative 90% particle size, and the total volume of the obtained particle size distribution is 100. In the cumulative curve with%, the particle size at the point where the cumulative value becomes 10% and 90% is shown. Therefore, the ratio (D ₉₀ / D ₁₀ ) between the 90% particle size (D ₉₀ ) and the 10% particle size (D ₁₀ ) can be considered as an index indicating the breadth of the particle size distribution. As the value of D ₉₀ / _{D 10} is large, it has a broad particle size distribution. As D ₉₀ / D ₁₀ is closer to 1, the particle size distribution is closer to monodispersion.

In the inorganic filler (D1) having an average particle diameter of 5 to 45 μm in the present invention, the value of D ₉₀ / D ₁₀ is preferably 40 or less, and more preferably in the range of 1 to 25.

In the inorganic filler (D2) having an average particle diameter of less than 5 μm in the present invention, the value of D ₉₀ / D ₁₀ is preferably 20 or less, and more preferably in the range of 1-15.

  The content ratio of the inorganic filler (D1) and the inorganic filler (D2) is 40:60 to 95: 5 (weight ratio), preferably 60:40 to 90:10 (weight ratio), and more. Preferably it is 70: 30-85: 15 (weight ratio).

  The shape of the inorganic filler (D) may be either spherical or irregular.

1-5. Polymerization catalyst (E)
The polyurethane resin composition of the present invention may further contain a polymerization catalyst (E) as necessary.

  As a polymerization catalyst (E), a well-known polymerization catalyst can be used, For example, metal catalysts, such as an organic tin catalyst, an organic lead catalyst, and an organic bismuth catalyst, an amine catalyst etc. are mentioned.

  Examples of the organic tin catalyst include dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, and dioctyltin diacetate.

  Examples of the organic lead catalyst include lead octylate, lead octenoate, lead naphthenate, and the like.

  Examples of the organic bismuth catalyst include bismuth octylate and bismuth neodecanoate.

  Examples of the amine catalyst include diethylenetriamine, triethylamine, N, N-dimethylcyclohexylamine, N, N, N ′, N′tetramethylethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, tri Examples include methylenediamine, dimethylaminoethanol, bis (2-dimethylaminoethyl) ether and the like. In addition, as the catalyst, an organometallic compound, a metal complex compound, or the like may be used.

  When the polymerization catalyst (E) is contained, the content is not particularly limited, and is preferably 0.00001 to 10% by weight with respect to 100% by weight of the polyurethane resin composition, and preferably 0.0001 to 5%. More preferably, it is% by weight.

  The said polymerization catalyst (E) can be used individually by 1 type, or 2 or more types can also be mixed and used for it.

1-6. Antifoam (F)
The polyurethane resin composition of the present invention may further contain an antifoaming agent (F) as necessary.

  The antifoaming agent used in the present invention is not particularly limited, and examples thereof include silicones (oil type, compound type, self-emulsifying type, emulsion type, etc.), alcohols and the like.

  As a preferable silicone-based antifoaming agent, a modified silicone-based antifoaming agent (particularly, a polysiloxane made of a lipophilic group and modified with a hydrophilic group) is preferable.

  The said antifoamer (F) can be used individually by 1 type, or 2 or more types can also be mixed and used for it.

  When the antifoaming agent (F) is contained, the content is not particularly limited, and 0.001 to 10% by weight is preferable with respect to 100% by weight of the polyurethane resin composition, and 0.01 to 5% by weight. % Is more preferable.

1-7. Other components The polyurethane resin composition of the present invention may further include, for example, a tackifier, a curing accelerator, a colorant, a chain extender, a crosslinking agent, a filler, a pigment, a filler, a flame retardant, and a urethanization. Various additives such as a catalyst, an ultraviolet absorber, an antioxidant, a moisture absorbent, an antifungal agent, and a silane coupling agent can be added.

  The content of these components may be appropriately determined from the normal addition amount and the range of identification so as not to inhibit the desired properties of the polyurethane resin composition according to the purpose of use.

  In addition, the polyurethane resin composition of this invention does not add a foaming agent. That is, the polyurethane resin composition of the present invention is intended for heat dissipation by an inorganic filler, whereas the foamed urethane foam containing a foaming agent is intended for heat insulation and the like, and both have different purposes. .

2. Method for Producing Polyurethane Resin Composition The method for producing the polyurethane resin composition of the present invention is not particularly limited, and can be produced according to a known method used as a method for producing a polyurethane resin composition.

  Examples of such a production method include a step of preparing a composition (first component) containing a hydroxyl group-containing compound (step 1), and a step of preparing a composition (second component) containing a polyisocyanate compound (step 2). And a method including a step (step 3) of mixing the second component and the first component to obtain a polyurethane resin composition.

  As long as the first component contains a hydroxyl group-containing compound and the second component contains a polyisocyanate compound, the other component may be contained in either the second component or the first component.

  For example, the structure in which a 1st component contains a hydroxyl-containing compound, a plasticizer, and an inorganic filler, and a 2nd component contains a polyisocyanate compound is mentioned.

The first component may contain a hydroxyl group-containing compound, a plasticizer, an inorganic filler, and an antifoaming agent, and the second component may contain a polyisocyanate compound and a polymerization catalyst;
The first component may contain a hydroxyl group-containing compound, a plasticizer, an antifoaming agent, an inorganic filler, and a catalyst, and the second component may contain a polyisocyanate compound;
The first component may contain a hydroxyl group-containing compound, a plasticizer and an antioxidant, and the second component may contain a polyisocyanate compound and an inorganic filler;
The first component may contain a hydroxyl group-containing compound, a plasticizer, an inorganic filler, and a polymerization catalyst, and the second component may contain a polyisocyanate compound and an antifoaming agent.

  In the polyurethane resin composition, the hydroxyl group-containing compound and the polyisocyanate compound may be partially or wholly reacted to form a polyurethane resin. That is, the polyurethane resin composition may be liquid before curing or may be cured. As a method of curing the polyurethane resin composition, by mixing the second component and the first component, the hydroxyl group-containing compound and the polyisocyanate compound react to form a polyurethane resin, whereby the polyurethane resin composition is aged over time. Although the method of making it harden | cure is mentioned, you may make it harden | cure by heating. In this case, the heating temperature is preferably about 40 to 120 ° C., and the heating time is preferably about 0.5 to 24 hours.

3. Use The present invention is also a sealing material comprising the polyurethane resin composition. The sealing material made of the polyurethane resin composition is excellent in heat dissipation, hydrolysis resistance and flame retardancy, and even when used in a high temperature environment, the reduction in flame retardancy is suppressed. Therefore, it can be suitably used for electrical and electronic parts that generate heat. Examples of such electric and electronic parts include transformers such as transformer coils, choke coils, and reactor coils, equipment control boards, and various sensors. Such electric and electronic parts are also one aspect of the present invention. The electric and electronic parts of the present invention can be used in electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, electric tools, automobiles, motorcycles, and the like.

  Hereinafter, the polyurethane resin composition of the present invention will be specifically described with reference to Examples and Comparative Examples. However, the examples are merely examples, and the present invention is not limited to the examples.

  The raw materials used in Examples and Comparative Examples are shown below.

Dimer acid polyol (A1)
a1: Dimer acid polyol having an average hydroxyl value of 206 mgKOH / g (trade name: Pripol 2033-LQ- (GD), manufactured by Claude Japan Co., Ltd.)
Castor oil-based polyol (A2)
a2: Castor oil-based polyol (trade name: castor oil, manufactured by Ito Oil Co., Ltd.)
Polybutadiene polyol (comparative product)
Comparative product: Polybutadiene polyol having an average hydroxyl value of 103 mgKOH / g (trade name: R-15HT, manufactured by Idemitsu Kosan Co., Ltd.)
Polyisocyanate compound (B)
b1: Isocyanurate modified product of hexamethylene diisocyanate (trade name: Duranate TLA-100, manufactured by Asahi Kasei Chemicals Corporation)
b2: Diphenylmethane diisocyanate (MDI) -based isocyanate (trade name: Millionate MTL, manufactured by Tosoh Corporation)
Plasticizer (C)
c1: Diisononyl phthalate (DINP)
(Product name: DINP, manufactured by J Plus Co., Ltd.)
Inorganic filler (D)
d1: Aluminum hydroxide (Showa Denko H-32, average particle size 8 μm)
(Product name: Aluminum hydroxide, Showa Denko KK)
d2: Aluminum hydroxide (Showa Denko H-42I, average particle size 1 μm)
(Product name: Aluminum hydroxide, Showa Denko KK)
Polymerization catalyst (E)
e1: Dioctyltin dilaurate (trade name: Neostan U-810, manufactured by Nitto Kasei Corporation)
Antifoam (F)
f1: SC-5570 (silicone-based, manufactured by Toray Dow Silicone Co., Ltd.)
Preparation of polyurethane resin composition <Examples 1 to 7 and Comparative Examples 1 to 5>
It mix | blended with the composition shown in following Table 1, and prepared the various polyurethane resin compositions in the following procedure.

  First, with the compounding amounts shown in Table 1, a hydroxyl group-containing compound, a plasticizer, an antifoaming agent, an inorganic filler, and a catalyst are added, and 2000 rpm is used using a mixer (trade name: manufactured by Shinkey Co., Ltd., trade name: Aritori Kentaro). 1 minute at 23 ° C., and then cooled to room temperature to obtain a mixture (first component).

  Subsequently, the polyisocyanate compound (second component) is added to the above mixture (first component) at the blending amount shown in Table 1 adjusted to 23 ° C., and mixed at 2000 rpm for 1 minute using the same mixer. Defoaming was performed to obtain polyurethane resin compositions of Examples and Comparative Examples.

  The mixing ratio of the second component and the first component was such that the active hydrogen (OH) in the hydroxyl group-containing compound was 1 equivalent with respect to 1 equivalent of the NCO group in the isocyanate group-containing compound.

Preparation of test piece (test piece) 130 × 130 × 3 mm molding die, 130 × 130 × 6 mm molding die, or a resin containing the materials listed in Table 1 in a molding die having an inner diameter of 30 mm and a height of 10 mm The composition was injected. Next, the resin composition was heated at 60 ° C. for 16 hours and then allowed to cure at room temperature for 1 day. Hardness, appearance of cured product (compatibility) with respect to the obtained cured product A (130 × 130 × 3 mm), cured product B (130 × 130 × 6 mm), or cured product C (diameter 30 mm and height 10 mm) Tests of moisture resistance, elongation (flexibility) and flame retardancy were carried out by the following methods. The results are shown in Table 1.

The hardness of the cured product C was measured according to JISK 6253 using an Asker A type hardness meter (manufactured by Kobunshi Keiki Co., Ltd.).

Hardened product appearance (compatible)
About the polyurethane resin composition described in the Example and comparative example after hardening, the surface state (appearance) of the obtained hardened | cured material A was observed visually, and compatibility was evaluated according to the following evaluation criteria.
○: Even after heating at 80 ° C. for 16 hours and then at 120 ° C. for 168 hours, no droplets and cloudiness are observed on the surface (no bleeding occurs).
Δ: Bleed does not occur after heating at 80 ° C. for 16 hours, but bleed occurs after heating at 120 ° C. for 168 hours. X: Bleed occurs after heating at 80 ° C. for 16 hours.
A pressure cooker test (PCT test) was performed on the moisture-resistant cured product C under the conditions of 121 ° C. and 100% RH 2 atm / 100 hours. The hardness before the test and the hardness after the test were measured according to JIS K 6253 using an Asker A type hardness meter (manufactured by Kobunshi Keiki Co., Ltd.), and the hardness retention was measured.
[Hardness retention] = {[(hardness before test) − (hardness after test)] ÷ (hardness after test)} × 100
Based on the calculated hardness reduction rate, the moisture resistance was evaluated according to the following evaluation criteria.
○: Hardness retention is 50% or more Δ: Hardness retention is 20% to less than 50% ×: Hardness retention is less than 20%
Elongation rate (flexibility )
The elongation (flexibility) of the cured product A was evaluated according to JISK 6251 based on the following formula.
Formula: Elongation rate = {[(Distance between marked lines at break) − (Distance between marked lines)] ÷ (Distance between marked lines)} × 100
○: Elongation rate is 50% or more ×: Elongation rate is less than 50%
Flame retardancy A flame retardancy test was conducted using test piece B, which is a cured product of the polyurethane resin compositions obtained in Examples and Comparative Examples. The test was conducted by Underwriters Laboratories, Inc., USA. Based on the combustion test standard (UL94) established by Flame retardancy was evaluated according to the following evaluation criteria.
○: V-0 is satisfied ×: V-0 is not satisfied (V-1, V-2 or HB)
<Result>
From the results of Examples 1 to 7, it was found that the polyurethane resin composition of the present invention satisfied all of elongation (flexibility), cured product appearance (compatibility), hardness, moisture resistance and flame retardancy. .

  On the other hand, from the result of Comparative Example 1, the polyurethane resin composition containing the polybutadiene polyol was inferior in elongation (flexibility) and compatibility.

  From the results of Comparative Examples 2 and 4, it was found that the polyurethane resin cured product containing no dimer acid polyol was inferior in elongation (flexibility) and / or moisture resistance.

  Moreover, from the result of Comparative Example 3, it was found that the cured polyurethane resin in which the content of the inorganic filler is 20% by weight in the polyurethane resin composition is inferior in flame retardancy.

  From the results of Comparative Example 5, it was found that the polyurethane resin composition having an inorganic filler content of about 90% cannot produce a uniform cured product.

  When the polyurethane resin composition of the present invention is used, the obtained polyurethane resin cured product exhibits excellent elongation (flexibility) and excellent compatibility, hardness, moisture resistance and flame retardancy. It can be used in the field of electronic parts.

Claims (4)

A polyurethane resin composition comprising a hydroxyl group-containing compound, a polyisocyanate compound, a plasticizer and an inorganic filler,
The hydroxyl group-containing compound includes a dimer acid polyol and a castor oil-based polyol,
The content ratio of the dimer acid polyol and the castor oil-based polyol is, by weight ratio, dimer acid polyol: castor oil-based polyol = 20: 80 to 80:20,
The content of the inorganic filler, the polyurethane resin composition, Ri 50-85 wt% der,
The polyisocyanate compound is an isocyanurate-modified product of hexamethylene diisocyanate.
Polyurethane resin composition. The polyurethane resin composition according to claim 1 , which is used for sealing electric and electronic parts. Sealing material made of a polyurethane resin composition according to claim 1 or 2. An electrical / electronic component sealed with a resin using the sealing material according to claim 3 .