JP2019182887A - Polyurethane resin composition - Google Patents

Abstract

To provide a polyurethane resin, which is excellent in compatibility and workability and in cold-heat cycle characteristics, using polybutadiene polyol having a hydroxyl value of 60 mgKOH/g or less.SOLUTION: A polyurethane resin composition contains (A) a polyisocyanate compound, (B) a polyol compound, (C) an inorganic filler and (D) a plasticizer, in which (B) the polyol compound contains (b1) polybutadiene polyol having a hydroxyl value of 60 mgKOH/g or less, and contains 50-85 mass% of (C) an inorganic filler and 1-30 mass% of (D) a plasticizer to 100 mass% of the polyurethane resin composition.SELECTED DRAWING: None

Description

  The present invention relates to a polyurethane resin composition.

  In recent years, due to advances in electronic circuit boards and electronic components, stress on members due to the thermal cycle is increasing, and members that can maintain high heat resistance and long-term heat dissipation are demanded.

  The polyurethane resin used for these seals has a problem in that it loses its flexibility due to a long-term cooling cycle and cracks are generated, and the temperature dependency of the elastic modulus can be further reduced and the member can be maintained for a long time. Development is an urgent need.

  For example, Patent Documents 1 to 3 describe using a polybutadiene polyol having a hydroxyl value of 20 to 120 mgKOH / g. However, these documents do not specifically disclose a polyurethane resin using a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less, and as a polyol compound, a polybutadiene polyol having a hydroxyl value of 100 mgKOH / g or more (Poly bd ( (Registered trademark) R-15HT or the like).

JP 2006-020439 A Japanese Patent Laying-Open No. 2015-131883 Japanese Patent Laying-Open No. 2015-089944

  An object of the present invention is to provide a polyurethane resin excellent in compatibility, workability, and cooling cycle characteristics using a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less.

  As a result of intensive studies to solve the above problems, the present inventor has found that the polyol compound contains a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less, and the inorganic filler is contained in 100% by mass of the polyurethane resin composition. It has been found that if the polyurethane resin composition contains 50 to 85% by mass and 1 to 30% by mass of a plasticizer, the above problems can be solved. The present invention has been completed based on such findings.

  That is, the present invention relates to the following polyurethane resin composition, sealing material, electric / electronic component and the like.

Item 1.
A polyurethane resin composition comprising (A) a polyisocyanate compound, (B) a polyol compound, (C) an inorganic filler, and (D) a plasticizer,
The (B) polyol compound includes (b1) a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less,
A polyurethane resin composition containing (C) an inorganic filler in an amount of 50 to 85% by mass and (D) a plasticizer in an amount of 1 to 30% by mass with respect to 100% by mass of the polyurethane resin composition.
Item 2.
Item 2. The polyurethane resin composition according to Item 1, wherein the number average molecular weight (Mn) of the (b1) polybutadiene polyol is in the range of 100 to 5,000.
Item 3.
Item 3. The polyurethane resin composition according to Item 1 or 2, wherein the (b1) polybutadiene polyol has a viscosity (30 ° C) in the range of 0.01 to 100 Pa · s.
The
Item 4.
Item 4. The polyurethane resin composition according to any one of Items 1 to 3, further comprising (E) a crosslinking agent.
Item 5.
Item 5. The polyurethane resin composition according to Item 4, wherein the (E) crosslinking agent is (E1) an aromatic alcohol-based crosslinking agent and / or (E2) an aliphatic alcohol-based crosslinking agent.
Item 6.
Item 6. The polyurethane resin composition according to Item 4 or 5, wherein the (E) crosslinking agent is (E1) an aromatic alcohol crosslinking agent.
Item 7.
Item 7. The polyurethane resin composition according to any one of Items 4 to 6, wherein the (E) crosslinking agent is a crosslinking agent having a number average molecular weight of 400 or less.
Item 8.
Item 8. The polyurethane resin composition according to any one of Items 1 to 7, wherein the (D) plasticizer includes (d1) an adipic acid plasticizer and / or (d2) a phthalic acid plasticizer.
Item 9.
Item 9. The polyurethane resin composition according to any one of Items 1 to 8, wherein the (D) plasticizer is (d1) an adipic acid-based plasticizer.
Item 10.
Item 10. The polyurethane resin composition according to any one of Items 1 to 9, wherein the (D) plasticizer contains 10 to 29% by mass with respect to 100% by mass of the polyurethane resin composition.
Item 11.
Item 11. The polyurethane resin composition according to any one of Items 1 to 10, which is used for sealing electric and electronic parts.
Item 12.
Item 12. A sealing material comprising the polyurethane resin composition according to any one of Items 1 to 11.
Item 13.
Item 13. An electrical and electronic component sealed with a resin using the sealing material according to Item 12.

  INDUSTRIAL APPLICABILITY The present invention can provide a polyurethane resin composition and a sealing material that are excellent in compatibility, workability, and excellent in thermal cycle characteristics.

  Specifically, the polyurethane resin composition and the sealing material of the present invention can reduce the temperature dependence of the elastic modulus (120 ° C. to −40 ° C.) and exhibit excellent elongation (flexibility) as the thermal cycle characteristics. In addition, changes in hardness, elongation (flexibility) and elastic modulus due to thermal degradation (after heat resistance) can be suppressed (100 ° C.).

  Therefore, the polyurethane resin composition and the sealing material of the present invention can be suitably used for, for example, insulation treatment of various electric and electronic parts.

  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 containing (A) a polyisocyanate compound, (B) a polyol compound, (C) an inorganic filler, and (D) a plasticizer,
The (B) polyol compound includes (b1) a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less,
(C) Inorganic filler is contained in an amount of 50 to 85% by mass and (D) a plasticizer is contained in an amount of 1 to 30% by mass with respect to 100% by mass of the polyurethane resin composition.

1-1. (A) Polyisocyanate compound “(A) Polyisocyanate compound” is not particularly limited as long as it has two or more isocyanate groups, and is a polyurethane resin composition (particularly, a polyurethane resin composition for sealing electric and electronic parts). It is possible to use various components that can be used or components that can be used.

(A) There is no limitation in particular as a polyisocyanate compound, For example,
(A1) aliphatic polyisocyanate compound,
(A2) alicyclic polyisocyanate compound,
(A3) a polyisocyanate compound such as an aromatic polyisocyanate compound;
Modified product of the polyisocyanate compound (a) (for example,
(A-1) isocyanurate body,
(A-2) a carbodiimide body,
(A-3) Adduct body,
(A-4) Biuret body,
(A-5) allophanate, etc.);
The polynuclear body (b) etc. of the said polyisocyanate compound are mentioned.

  Examples of the (A1) aliphatic polyisocyanate compound include tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethyl. Examples include hexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, and 3-methylpentane-1,5-diisocyanate, and 1,6-hexamethylene diisocyanate (HDI) is preferred.

  Moreover, as said (A1) aliphatic polyisocyanate compound, the isocyanurate body of (A1a-1) aliphatic polyisocyanate compound is preferable. For example, the isocyanurate-modified 1,6-hexamethylene diisocyanate used in the present invention is an isocyanate having an isocyanate group at the terminal derived from 1,6-hexamethylene diisocyanate (hereinafter abbreviated as “HDI”). Nurate compounds are used. Specific examples thereof include Duranate (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TSE-100, TSE-100 and TLA-100 manufactured by Asahi Kasei Kogyo Co., Ltd .; Sumitomo Bayer Urethane Desmodule (registered trademark) N3390 manufactured by Co., Ltd .; Coronate (registered trademark) EH manufactured by Nippon Polyurethane Co., Ltd .; Takenate D170N manufactured by Takeda Pharmaceutical Co., Ltd .; Burnock manufactured by Dainippon Ink & Chemicals, Inc. (DIC Corporation) (Registered trademark) DN980 and the like.

  Examples of (A2) alicyclic polyisocyanate compounds include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate (hydrogenated 4,4′-diphenylmethane diisocyanate, HMDI), 1,4 -Cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane and the like.

  The hydrogenated 4,4'-diphenylmethane diisocyanate used in the present invention is a polyisocyanate hydrogenated with 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as MDI). Specific examples thereof include WANNATE (registered trademark) HMDI manufactured by Wanhua Chemical Japan.

  Examples of the aromatic polyisocyanate compound (A3) include tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), and 4,4′-di. Benzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethylxylylene diene Isocyanate, etc. are mentioned, Preferably 2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-di It is E methane diisocyanate (MDI).

  As the 4,4'-diphenylmethane diisocyanate (MDI) used in the present invention, a polyisocyanate (carbodiimide-modified MDI) having a carbodiimide group derived from 4,4'-diphenylmethane diisocyanate is used. Specific examples thereof include Millionate (registered trademark) MTL manufactured by Tosoh Corporation.

  (A) Although the viscosity of a polyisocyanate compound changes greatly according to the kind of polyisocyanate compound, the presence or absence of modification, etc., it is not particularly limited. For example, in the case of an aromatic polyisocyanate compound and a modified product and a polynuclear product thereof (preferably a carbodiimide product and a polynuclear product of an aromatic polyisocyanate compound), the viscosity at 25 ° C. is, for example, 5 to 200 mPa · s, preferably 10 It is -150 mPa * s, More preferably, it is 15-100 mPa * s, More preferably, it is 20-80 mPa * s. As another example, in the case of an aliphatic polyisocyanate compound and modified products and polynuclear products thereof (preferably an isocyanurate form of an aliphatic polyisocyanate compound), the viscosity at 25 ° C. is, for example, 100 to 3000 mPa · s, preferably It is 500-2500 mPa * s, More preferably, it is 1000-2000 mPa * s, More preferably, it is 1200-1700 mPa * s.

  (A) Although the NCO content of a polyisocyanate compound is not specifically limited, For example, it is 15 to 45%, More preferably, it is 20 to 40%, More preferably, it is 20 to 35%.

As said (A) polyisocyanate compound, from the viewpoint that heat resistance and hydrolysis resistance can be further improved, (Aa-1) isocyanurate of polyisocyanate compound (more preferably (A1a-1) ) Isocyanurate of an aliphatic polyisocyanate compound),
(A2) an alicyclic polyisocyanate compound (more preferably a hydrogenated product of 4,4′-diphenylmethane diisocyanate),
(A3) An aromatic polyisocyanate compound (polyisocyanate having a carbodiimide group derived from 4,4′-diphenylmethane diisocyanate (carbodiimide-modified MDI)) and the like.

  Among these, as a commercially available product of preferable (A) polyisocyanate compound, for example, Duranate (registered trademark) TPA-100 (manufactured by Asahi Kasei Chemicals), Luplanate (registered trademark) M5S (manufactured by BASF INOAC polyurethane), WANNAT ( (Registered trademark) HMDI (hydrogenated MDI, manufactured by Wanhua Chemicals Japan Co., Ltd.), Millionate (registered trademark) MTL (produced by Tosoh Corporation), and the like.

  (A) A polyisocyanate compound can also be used individually by 1 type, and can also be used in combination of arbitrary 2 or more types.

  Especially, it is preferable to use 2 types as this (A) polyisocyanate compound, and it is more preferable to use the mixture of the isocyanurate body of (Aa-1) polyisocyanate compound, and (A2) alicyclic polyisocyanate compound. Preferably, it is more preferable to use a mixture of an isocyanurate form of (A1a-1) an aliphatic polyisocyanate compound and a hydrogenated product of (A2) 4,4′-diphenylmethane diisocyanate.

(A) Content of a polyisocyanate compound is not specifically limited as long as it is the quantity which can be employ | adopted in a polyurethane resin composition (especially polyurethane resin composition for electrical / electronic component sealing). As this content, for example with respect to 100 mass% of polyurethane resin compositions, it is 0.01-25 mass% normally, Preferably it is 0.1-20 mass%, More preferably, it is 1-10 mass% Especially preferably, it is 1.5-6 mass%.
Moreover, content of (A) polyisocyanate compound is 5-75 mass parts with respect to 100 mass parts of (B) polyol compounds, Preferably it is 8-65 mass parts, More preferably, it is 10-60 mass parts. is there.

  In the polyurethane resin composition of the present invention, when two or more types of (A) polyisocyanate compounds are blended, the total amount can be prepared in accordance with the content of the above-mentioned (A) polyisocyanate compound. For example, when (A) polyisocyanate compound is blended with an isocyanurate of (Aa-1) polyisocyanate compound and (A2) alicyclic polyisocyanate compound, (Aa-1) isocyanurate of polyisocyanate compound As content of a body, it is 1-400 mass parts normally with respect to 100 mass parts of (A2) alicyclic polyisocyanate compound, Preferably it is 10-380 mass parts, More preferably, it is 100-350 mass parts. Part.

  In the polyurethane resin composition of the present invention, when the (A3) aromatic polyisocyanate compound is contained, the content thereof is usually 0.01 to 25% by mass with respect to 100% by mass of the polyurethane resin composition. , Preferably, it is 1-10 mass%, More preferably, it is 2-4 mass%.

  The amount of the (A) polyisocyanate compound and the following (B) polyol compound is such that the NCO / OH ratio (INDEX), which is the ratio of the number of moles of isocyanate groups in the polyisocyanate compound to the number of moles of hydroxyl groups in the polyol compound, is 0. 0.5 to 1.5, preferably 0.7 to 1.3, more preferably 0.8 to 1.1.

  Further, when (A) the polyisocyanate compound contains an isocyanurate form of (Aa) polyisocyanate compound (more preferably (A1a-1) isocyanurate form of an aliphatic polyisocyanate compound), the content is heat resistant. From the viewpoint that the property and the hydrolysis resistance can be further improved, it is usually 1 to 80 parts by mass, preferably 10 to 80 parts by mass with respect to 100 parts by mass of the (A) polyisocyanate compound, More preferably, it is 30-80 mass parts, More preferably, it is 50-80 mass parts.

  In addition to (A) the polyisocyanate compound (Aa-1) isocyanurate of the polyisocyanate compound (more preferably (A1a-1) isocyanurate of the aliphatic polyisocyanate compound), (Ab) polyisocyanate compound Or (A3b) a polynuclear compound of an aromatic polyisocyanate compound (preferably (A3b) a polynuclear body of an aromatic polyisocyanate compound) ) And (Aa-2) a carbodiimide form of a polyisocyanate compound (preferably (A3a-2) a carbodiimide form of an aromatic polyisocyanate compound), the content of (Ab) and / or (Aa-2) Is it a viewpoint that electric characteristics can be improved more? , (Aa-1) The polyisocyanate compound is 100 parts by mass, for example, 1 to 1000 parts by mass, preferably 5 to 800 parts by mass, more preferably 8 to 700 parts by mass, and still more preferably 65 to 500 parts by mass. .

1-2. (B) Polyol Compound The (B) polyol compound used in the present invention contains (b1) a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less (hereinafter sometimes referred to as “(b1) polybutadiene polyol”).

  (B1) As a commercially available polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less, for example, polybutadiene polyol [NISSO-PBG series manufactured by Nippon Soda Co., Ltd. (G-1000, G-2000, G-3000, etc.), US "Poly Bd (registered trademark) series" (R-45M, R-45HT, CS-15, CN-15, etc.)] manufactured by ARCO.

  (B1) The hydroxyl value of the polybutadiene polyol is preferably 1 to 58 mgKOH / g, more preferably 5 to 55 mgKOH / g, and particularly preferably 10 to 50 mgKOH / g.

  (B1) The hydroxyl group content of the polybutadiene polyol is not particularly limited, and is usually 0.001 to 3 mol / kg, preferably 0.01 to 2 mol / kg, more preferably 0.1 to 1.2 mol. / Kg.

  (B1) The number average molecular weight (Mn) of the polybutadiene polyol is usually in the range of 100 to 5000, preferably in the range of 1000 to 4000, and more preferably in the range of 1500 to 3500.

(B1) The viscosity of the polybutadiene polyol (30 ° C.) is usually in the range of 0.01 to 100 Pa · s, preferably in the range of 0.1 to 100 Pa · s, more preferably 1 to 10 Pa · s. It is a range.
The

(B1) The iodine value of the polybutadiene polyol is usually in the range of 1 to 1000 g / 100 g, preferably in the range of 10 to 600 Pa · s, and more preferably in the range of 100 to 500 Pa · s.
The

  The (b1) polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less can be used alone or in combination of two or more.

  The (B) polyol compound used in the present invention further comprises a polyol compound (b2) (hereinafter referred to as “(b2) polyol”) containing one or more hydroxyl groups other than the polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less. Can be contained.

  (B2) Examples of the polyol include dimer acid polyols; castor oil-based polyols; polydiene polyols (polyisoprene polyols and the like); polyether polyols; polyester polyols; polycarbonate polyols; polycaprolactone polyols; acrylic polyols; For example, polydiene polyol hydride and the like.

  There is no restriction | limiting in particular as a dimer acid polyol, A well-known dimer acid polyol can be used.

  There is no restriction | limiting in particular as a castor oil type | system | group polyol, For example, a castor oil, a castor oil derivative, etc. are mentioned.

  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; a compound 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.

  Examples of the hydrogenated castor oil include those disclosed in JP-A-2-298574. Hydrogenated castor oil can be obtained by hydrogenation of the aforementioned castor oil-based polyol.

  The number average molecular weight (Mn) of the castor oil-based polyol is usually in the range of 100 to 4000, and preferably in the range of 300 to 2500.

  The castor oil-based polyol 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) can be measured by a gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the number average molecular weight by the GPC method is Shodex GPC System 21 manufactured by Showa Denko KK as a measuring device, and Shodex LF-804 / KF-803 / KF-804 manufactured by Showa Denko KK as a column. Measured at a column temperature of 40 ° C. using NMP as a mobile phase, and can be calculated using a standard polystyrene calibration curve.

  There is no restriction | limiting in particular as polydiene polyol, For example, polyisoprene polyol [Idemitsu Kosan Co., Ltd. product "Poly ip"] etc. are mentioned.

  The hydride of polydiene polyol is not particularly limited. For example, a hydride of polybutadiene polyol [NISO-PBGI series (GI-1000, GI-2000, GI-3000, etc.) manufactured by Nippon Soda Co., Ltd.], Hydride of polyisoprene polyol [“Epol” manufactured by Idemitsu Kosan Co., Ltd.] and the like.

  There is no restriction | limiting in particular as polyether polyol, For example, water, a low molecular polyol (propylene glycol, ethylene glycol, glycerol, a trimethylol propane, pentaerythritol, etc.), bisphenols (bisphenol A etc.), dihydroxybenzene (catechol, resorcinol) 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.

  There is no restriction | limiting in particular as polyester polyol, For example, it can obtain by esterification reaction of a polyol component and an acid component.

  The polyol component is not particularly limited. For example, ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 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-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polypropylene glycol and the like can be mentioned.

  The acid component is not particularly limited. For example, 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 Examples include '-biferrodicarboxylic acid and acid anhydrides thereof.

  There is no restriction | limiting in particular as a polycarbonate polyol, For example, the polycarbonate polyol obtained by carrying out the polycondensation reaction of the said polyol component and phosgene; The said polyol component, Dimethyl carbonate, Diethyl carbonate, Dipropyl carbonate, Diisopropyl carbonate, Dibutyl carbonate, Ethyl butyl Polycarbonate polyols obtained by transesterification with carbonic acid diesters such as carbonic acid, ethylene carbonate, propylene carbonate, diphenyl carbonate and dibenzyl carbonate; copolymer polycarbonate polyols obtained by using two or more of the above polyol components in combination; Polycarbonate polyols obtained by esterifying a polyol and a carboxyl group-containing compound; the above-mentioned various polycarbonate polyols and hydroxyl Polycarbonate polyol obtained by etherification reaction of the containing compound; polycarbonate polyol obtained by transesterification of the various polycarbonate polyols and ester compounds; obtained by transesterification of the various polycarbonate polyols and hydroxyl group-containing compounds. Polycarbonate polyols obtained by polycondensation reaction between the above-mentioned various polycarbonate polyols and dicarboxylic acid compounds; copolymer polyether-based polycarbonate polyols obtained by copolymerizing the above various polycarbonate polyols and alkylene oxides, etc. Can be mentioned.

  The polycaprolactone polyol is not particularly limited, and examples thereof include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and δ-valerolactone.

  Examples of the acrylic polyol include a copolymer obtained by copolymerizing a hydroxyl group-containing acrylate and a copolymerizable vinyl monomer copolymerizable with the hydroxyl group-containing acrylate.

  Examples of the hydroxyl group-containing acrylate include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2,2-dihydroxymethylbutyl (meth) acrylate, polyhydroxyalkyl maleate, Examples include polyhydroxyalkyl fumarate. Preferably, 2-hydroxyethyl (meth) acrylate etc. are mentioned.

Examples of the copolymerizable vinyl monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and s-butyl ( Alkyls such as (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, isononyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl acrylate, etc. (Meth) acrylate (C1-12);
For example, aromatic vinyl such as styrene, vinyltoluene, α-methylstyrene;
For example, vinyl cyanide such as (meth) acrylonitrile;
For example, a vinyl monomer containing a carboxyl group such as (meth) acrylic acid, fumaric acid, maleic acid, itaconic acid, or an alkyl ester thereof;
For example, ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, oligoethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) ) Alkane polyol poly (meth) acrylates such as acrylates;
For example, a vinyl monomer containing an isocyanate group such as 3- (2-isocyanate-2-propyl) -α-methylstyrene can be used.

  The acrylic polyol can be obtained by copolymerizing these hydroxyl group-containing acrylate and copolymerizable vinyl monomer in the presence of a suitable solvent and polymerization initiator.

  The acrylic polyol includes, for example, silicone polyol, fluorine polyol and the like.

  Examples of the silicone polyol include an acrylic polyol in which a silicone compound containing a vinyl group such as γ-methacryloxypropyltrimethoxysilane is blended as the copolymerizable vinyl monomer in the copolymerization of the acrylic polyol described above. It is done.

  As the fluorine polyol, for example, in the copolymerization of the acrylic polyol described above, as the copolymerizable vinyl monomer, for example, an acrylic polyol in which a fluorine compound containing a vinyl group such as tetrafluoroethylene or chlorotrifluoroethylene is blended can be cited. It is done.

  The vinyl monomer-modified polyol can be obtained by a reaction between the above-described high molecular weight polyol and a vinyl monomer.

  The (B) polyol compound used in the present invention can be (b1) a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less alone, or (b1) a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less and a hydroxyl value of 60 mgKOH / g. It is also possible to use a mixture with a hydroxyl group-containing compound (b2) other than g or less polybutadiene polyol. As the (b1) polybutadiene polyol, two or more kinds of polybutadiene polyols having different molecular weights can be used. Two or more kinds of the hydroxyl group-containing compound (b2) other than the polybutadiene polyol can be mixed and used.

  The polyurethane resin composition of this invention can improve the moisture resistance and heat cycle property of a polyurethane resin composition by containing a polybutadiene polyol (B-1) as a hydroxyl-containing compound.

  The content of the (b1) polybutadiene polyol used in the present invention is not particularly limited, and is usually 0.01 to 25% by mass, preferably 1 to 20% by mass with respect to 100% by mass of the polyurethane resin composition. More preferably, it is 5 to 15% by mass.

1-3. (C) Inorganic filler The polyurethane resin composition of the present invention contains (C) an inorganic filler.

  The inorganic filler (C) used in the present invention is not particularly limited, and examples thereof include metal hydroxides, metal oxides, metal nitrides, and zeolites.

  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 those used in known polyurethane resin compositions can be used.

  Among them, the zeolite is preferably an alkali metal or alkaline earth metal crystalline hydrous aluminosilicate.

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

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

  (C) As content of an inorganic filler, it is 50-85 mass% normally with respect to 100 mass% of polyurethane resin compositions, Preferably it is 52-75 mass%, More preferably, it is 54-70 mass%. And particularly preferably 55 to 69% by mass.

(C) The shape of the inorganic filler may be either spherical or indefinite.
1-4. (D) Plasticizer The polyurethane resin composition of the present invention contains (D) a plasticizer.

  The (D) plasticizer used in the present invention is not particularly limited, and examples thereof include phthalate ester plasticizers such as dioctyl phthalate, diisononyl phthalate (diisononyl phthalate) and diundecyl phthalate; dioctyl adipate, diisononyl adipate, diisodecyl adipate Adipate plasticizers such as methyl acetyl ricinoleate, butyl acetyl ricinolate, acetylated ricinoleic acid triglyceride, acetylated polyricinoleic acid triglyceride, etc .; trioctyl trimellitate, triisononyl tri And trimellitic acid esters such as melitrate; pyromellitic acid ester plasticizers such as tetraoctyl pyromellitate and tetraisononyl pyromellitate. Among these, phthalic acid ester plasticizers and adipic acid ester plasticizers are preferable, and adipic acid ester plasticizers are more preferable.

  (D) As content of a plasticizer, it is 1-30 mass% normally with respect to 100 mass% of polyurethane resin compositions, Preferably it is 10-29 mass%, More preferably, it is 12-28 mass%. It is particularly preferably 15 to 26% by mass.

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

1-5. (E) Cross-linking agent (chain extender)
The polyurethane resin composition of the present invention may further contain (E) a crosslinking agent (also known as a chain extender).
(E) The crosslinking agent is not particularly limited, and examples thereof include N, N-bis (2-hydroxypropyl) aniline, hydroquinone-bis (β-hydroxyethyl) ether, resorcinol-bis (β-hydroxyethyl) ether, and the like. (E1) aromatic alcohol-based crosslinking agent,
(E2) aliphatic alcohol-based crosslinking agents such as ethylene glycol, 1,4-butanediol, octanediol, trimethylolpropane, triisopropanolamine;
Phenylenediamine, tolylenediamine, diphenyldiamine, 4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 1,2-bis (2-aminophenylthio) ethane, trimethylene glycol -(E3) aromatic amine crosslinkers such as p-aminobenzoate;
Examples include (E4) aliphatic amine-based crosslinking agents such as ethylenediamine, propylenediamine, hexamethylenediamine, and diethylenetriamine.

Among these, (E1) aromatic alcohol crosslinking agent and (E2) aliphatic alcohol crosslinking agent are preferable, and (E1) aromatic alcohol crosslinking agent is more preferable.

  The number average molecular weight of the (E) crosslinking agent is usually 1000 or less, preferably 500 or less as the number average molecular weight, more preferably 400 or less as the number average molecular weight.

  When the polyurethane resin composition of the present invention contains (E) a crosslinking agent, the content of (E) the crosslinking agent is not particularly limited. For example, the content is usually 0.01 with respect to 100% by mass of the polyurethane resin composition. It is -30 mass%, Preferably it is 0.1-20 mass%, More preferably, it is 0.3-10 mass%, Most preferably, it is 0.5-5 mass%.

  Said (E) crosslinking agent 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.

  A preferred silicone antifoaming agent is a modified silicone antifoaming agent (particularly, a polysiloxane made of a lipophilic group and modified with a hydrophilic group).

  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 mass is preferable with respect to 100% by mass of the polyurethane resin composition, and preferably 0.005 to 5% by mass. Is more preferable.

1-7. (G) Polymerization catalyst The polyurethane resin composition of the present invention may further contain (G) a polymerization catalyst, if necessary.

  (G) As a polymerization catalyst, 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.

  (G) When a polymerization catalyst is contained, the content thereof is not particularly limited, and is usually 0.00001 to 10% by mass, preferably 0.0001 to 5% with respect to 100% by mass of the polyurethane resin composition. It is mass%, More preferably, it is 0.001-1 mass part.

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

1-8. Other components The polyurethane resin composition of the present invention may further comprise an antioxidant, a tackifier, a curing accelerator, a colorant, a chain extender, a crosslinking agent, a filler, a pigment, a filler, a flame retardant, if necessary. Various additives such as a urethanization catalyst, an ultraviolet absorber, a moisture absorbent, an antifungal agent, and a silane coupling agent can be included.

  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, a foaming agent is not added to the polyurethane resin composition of the present invention. 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.

  As such a production method, for example, (A) a step of preparing a composition (first component) containing a polyisocyanate compound (step 1), and (B) a composition (second component) containing a polyol compound are prepared. And a method including a step (step 2) of mixing the second component and the first component to obtain a polyurethane resin composition (step 3).

  If the first component (I agent) contains the (A) polyisocyanate compound and the second component (II agent) contains the (B) polyol compound, the other components are the second component or the second component. It may be contained in any one component.

  Here, in addition to the (A) polyisocyanate compound, the first component (agent I) can contain other components.

  In addition to the (B) polyol compound, the second component (II agent) can contain other components.

  For example, when the first component (I agent) contains a polyol compound in addition to the (A) polyisocyanate compound, the first component (I agent) is a urethane prepolymer having an isocyanate group (NCO) at the terminal. May be.

  Similarly, when the second component (II agent) contains (A) a polyisocyanate compound in addition to the (B) polyol compound, the second component (II agent) is a urethane prepolymer having a hydroxyl group (OH) at the terminal. It may be a polymer.

  Specifically, the (X) urethane prepolymer is obtained by reacting a component containing (A) a polyisocyanate compound and (B) a polyol compound. The (X) urethane prepolymer includes not only the urethane prepolymer obtained by reacting the material comprising the components (A) and (B), but also the components (A) and (B), and (E ) Urethane prepolymers obtained by reacting with a crosslinking agent and optional components are also applicable, and may contain other components as described above.

More specifically, as the polyurethane resin composition of the present invention, for example, the first component contains (A) a polyisocyanate compound and (D) a plasticizer, and the second component contains (B) a polyol compound and (C). Configuration containing an inorganic filler; first component containing (A) a polyisocyanate compound, and second component containing (B) a polyol compound, (C) an inorganic filler, and (D) a plasticizer;
Examples include a configuration in which the first component contains (A) a polyisocyanate compound and (D) a plasticizer, and the second component contains (B) a polyol compound, (C) an inorganic filler, and (D) a plasticizer. .

The first component contains (A) a polyisocyanate compound and (C) an inorganic filler, and the second component contains (B) a polyol compound;
The first component contains (A) a polyisocyanate compound and (D) a plasticizer, and the second component contains (B) a polyol compound, (C) an inorganic filler, (D) a plasticizer and (E) a crosslinking agent. Configuration to do;
The first component contains (A) a polyisocyanate compound and (D) a plasticizer, and the second component is (B) a polyol compound, (C) an inorganic filler, (D) a plasticizer, (E) a crosslinking agent, and ( F) Configuration containing an antifoaming agent;
The first component contains (A) a polyisocyanate compound and (D) a plasticizer, and the second component is (B) a polyol compound, (C) an inorganic filler, (D) a plasticizer, (E) a crosslinking agent, F) The structure containing an antifoamer and (G) a polymerization catalyst may be sufficient.

When manufacturing a polyurethane resin composition, the said 1st component (I agent) is 1-1000 mass parts normally with respect to 100 mass parts of 2nd components (II agent), Preferably it is 3-100 mass parts. Preferably it is 5-25 mass parts.
The reason why other components are blended with the first component is to reduce the viscosity of the polyisocyanate compound and to match the ratio (blending ratio) between the first component and the second component. Therefore, the first component can be used without blending other components.

  In the polyurethane resin composition, (A) the polyisocyanate compound and (B) the polyol compound may partially or completely react to form a polyurethane resin. That is, the polyurethane resin composition may be in a liquid state before being cured or may be cured. As a method of curing the polyurethane resin composition, by mixing the first component and the second component, the (A) polyisocyanate compound and the (B) polyol compound react to form a polyurethane resin. Although the method of hardening a resin composition with time 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. For this reason, 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 bases, and various sensors. Such electric and electronic parts are also one aspect of the present invention. The electric / electronic component of the present invention can be used in, for example, an electric washing machine, toilet seat, water heater, water purifier, bath, dishwasher, electric tool, automobile, motorcycle, 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.

<(A) Polyisocyanate compound>
а1: TPA-100
Product name: Duranate (registered trademark) TPA-100 (modified HDI isocyanurate), manufactured by Asahi Kasei Chemicals Corporation а2: HMDI
Product name: WANNATE (registered trademark) HMDI (hydrogenated MDI), Manka Chemical Japan Co., Ltd. а3: MTL
Product name: Millionate (registered trademark) MTL (carbodiimide-modified MDI), manufactured by Tosoh Corporation

<(B) polyol compound>
b1: R-45HT
Product name: Poly bd (registered trademark) R-45 HT, manufactured by Idemitsu Petrochemical Co., Ltd., number average molecular weight 2800, hydroxyl value 46.6 mg KOH / g (JIS K 1557), hydroxyl group content 0.83 mol / kg (JIS K 1557) , Iodine value 398g / 100g (JIS K 0070), Viscosity 5Pa ・ S / 30 ℃ (JIS K 2283)
b2 (Comparison polyol compound): R-15HT
Product name: Poly bd (registered trademark) R-15 HT, manufactured by Idemitsu Petrochemical Co., Ltd., number average molecular weight 1200, hydroxyl value 102.7 mg KOH / g (JIS K 1557), hydroxyl group content 1.83 mol / kg (JIS K 1557) , Iodine number 420g / 100g (JIS K 0070), viscosity 1.5Pa ・ S / 30 ℃ (JIS K 2283)

<(C) Inorganic filler>
c1: H-32
Product name: Heidilite (registered trademark) H-32 (aluminum hydroxide), manufactured by Showa Denko KK

<(D) Plasticizer>
d1: Diisodecyl adipate (DIDA)
Product name: DIDANB, Taoka Chemical Co., Ltd. d2: Diundecyl phthalate (DUP)
Product Name: DUP, made by J Plus

<(E) Crosslinking agent>
e1: OK All 100: Trade name, manufactured by Okabata Sangyo Co., Ltd., molecular weight 212
e1: Octanediol: trade name, manufactured by KH Neochem Co., Ltd., molecular weight 145

<(F) Antifoaming agent>
f1: SC-5570
Product name: SC-5570 (silicone defoaming agent), manufactured by Toray Dow Corning

<(G) Polymerization catalyst>
g1: U-810
Neostan U-810 (dioctyltin dilaurate): Product name, manufactured by Nitto Kasei Co., Ltd.

Preparation of polyurethane resin composition <Examples 1 to 11 and Comparative Examples 1 to 4>
Each component and 0.01% by weight of SC-5570 (silicone antifoaming agent) were blended as components and an antifoaming agent in the composition shown in Table 1, and various polyurethane resin compositions were prepared according to the following procedures.

(B) polyol compound, (C) inorganic filler, (D) plasticizer, (E) cross-linking agent, (F) antifoaming agent and (G) polymerization catalyst shown in Table 1 are mixed with a rotating / revolving mixer. Taro, manufactured by Shinky Corp.) and mixed at 2000 rpm for 1 minute.
The polyisocyanate compound (A) shown in Table 1 was added to the above-mentioned mixed components, and mixed for 1 minute at 2000 rpm using a rotation / revolution mixer (Awatori Kentaro, manufactured by Shinky Corp.). The obtained mixture was degassed to obtain each polyurethane resin composition of Examples 1 to 11 and Comparative Examples 1 to 4.

<Preparation of test piece>
The prepared polyurethane resin composition was poured into a molding die of 100 × 100 × 3 mm, or a molding die having an inner diameter of 30 mm and a height of 10 mm, and 10 × 80 × 3 mm. Next, the polyurethane resin composition was heated at 60 ° C. for 16 hours and then allowed to stand at room temperature for 1 day to be cured, and test piece A (130 × 130 × 3 mm), test piece B (diameter 30 mm and height 10 mm). ) And test piece C (10 × 80 × 3 mm).

  A No. 3 type dumbbell test piece D described in JIS K 6251 is prepared as the test piece A, and a measurement temperature of 25 ° C. and a tensile speed of 500 mm are prepared using this test piece according to the method defined in JIS K6251 item 3. A tensile test was performed under the conditions of / min, and the elongation (flexibility) was measured. The results are shown in Table 1.

  Moreover, hardness, compatibility, and heat resistance for the obtained test piece A (130 × 130 × 3 mm), test piece B (diameter 30 mm and height 10 mm) and test piece C (10 × 80 × 3 mm). Properties, elastic modulus (DMS method: 10 Hz), and volume resistance were measured by the following test methods. The results are shown in Table 1.

<Hardness>
The hardness (type A) when the temperature of the test piece B (the cured product B, inner diameter 30 mm, height 10 mm) is 23 ° C. is measured in accordance with JIS K 6253. ).

<Compatibility (outline)>
The mixture of “polyol compound, cross-linking agent, plasticizer, antifoaming agent, inorganic filler, polymerization catalyst” is heated in a dryer at 60 ° C. for 1 week, cooled to room temperature (23 ° C.), and then the appearance is improved. confirmed.

A: There is no transparent layer (phase separation) in the upper layer (supernatant) of the mixed liquid.
C: There is a transparent layer (phase separation) in the upper layer (supernatant) of the mixed liquid.

<Heat resistance>
After the initial hardness measurement, the specimen B was heated with a dryer at 100 ° C. for 500 hours, cooled to room temperature (23 ° C.), and then the hardness (final hardness) of the specimen was measured in the same manner as the initial hardness. From the initial hardness and the final hardness, the hardness change rate was calculated based on the following formula.

Formula: Hardness change rate (%) = [(final hardness−initial hardness) / initial hardness] × 100
Based on the calculated rate of change in hardness, heat resistance was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

A: Hardness change rate is less than 30%.
C: Hardness change rate is 30% or more.

<Elongation rate (flexibility)>
The elongation percentage (flexibility) of the test piece D was evaluated based on the following formula according to JIS K 6251.

Formula: Elongation rate = {[(Distance between marked lines at break) − (Distance between marked lines)] ÷ (Distance between marked lines)} × 100
A: Elongation rate is 100% or more C: Elongation rate is less than 100%

<Elastic modulus (10 Hz)>
The elastic modulus (10 Hz) of the test piece C was measured using a dynamic viscoelasticity measuring device: DMS (manufactured by SII Nano Technology: DMS6100). The elastic modulus was evaluated according to the following evaluation criteria.
An elastic modulus (10 Hz) at −40 ° C. is 40 MPa or less as an acceptable value.

The elastic modulus change (MPa) of the test piece C was evaluated based on the following formula.
Formula: Elastic Modulus Change (MPa) = [− 40 ° C. Elastic Modulus (MPa)] − [120 ° C. Elastic Modulus (MPa)]
The elastic modulus change from −40 ° C. to 120 ° C. is 30 MPa or less as an acceptable value.

<Volume resistance value>
The volume resistivity of the test piece A was measured using a resistance measuring instrument (manufactured by HIOKI, DSM-8104). Based on the measurement results, the insulation was evaluated according to the following evaluation criteria. Table 1 shows the measured values (Ω · cm) of volume resistivity and the evaluation results.
Volume resistivity is 1 × 10 ¹² Ω · cm or more.

<Judgment result>
From the results of Examples 1 to 11, the polyurethane resin composition of the present invention can reduce the temperature dependence of the elastic modulus (120 ° C. to −40 ° C.), exhibits excellent elongation (flexibility), and is due to thermal degradation. The change in hardness could be suppressed.

  Furthermore, it was found that the polyurethane resin composition of the present invention satisfies all items of excellent compatibility, hardness, and volume resistance.

  On the other hand, regarding Comparative Examples 1 to 4, the composition is not a composition that can satisfy all the items of temperature dependence of elastic modulus, elongation rate (flexibility), change in hardness due to thermal deterioration, compatibility, hardness, and volume resistance value. I understood it.

  Among Examples 1 to 11 above, for Example 1, Example 4 and Example 11, the elongation and elastic modulus were compared with those measured in heat-resistant 100 ° C./700 hours, compared with Comparative Example 4, It was shown in 2.

<Judgment result>
From the results of Example 1, Example 4 and Example 11, the polyurethane resin composition of the present invention has a modulus of elasticity and an elongation rate (flexibility) of Comparative Example 4 even after standing at 100 ° C./700 hours. And was able to suppress changes in hardness due to thermal degradation.

If the polyurethane resin composition of the present invention is used, the resulting polyurethane resin cured product satisfies all the items of heat resistance, moisture resistance, and heat cycleability, and therefore can be used in the fields of electrical products, electronic components, and the like. Is possible

Claims (13)

A polyurethane resin composition comprising (A) a polyisocyanate compound, (B) a polyol compound, (C) an inorganic filler, and (D) a plasticizer,
The (B) polyol compound includes (b1) a polybutadiene polyol having a hydroxyl value of 60 mgKOH / g or less,
A polyurethane resin composition containing (C) an inorganic filler in an amount of 50 to 85% by mass and (D) a plasticizer in an amount of 1 to 30% by mass with respect to 100% by mass of the polyurethane resin composition. The polyurethane resin composition according to claim 1, wherein the number average molecular weight (Mn) of the (b1) polybutadiene polyol is in the range of 100 to 5,000. The polyurethane resin composition according to claim 1 or 2, wherein the viscosity (30 ° C) of the (b1) polybutadiene polyol is in the range of 0.01 to 100 Pa · s.
The Furthermore, the polyurethane resin composition as described in any one of Claims 1-3 containing (E) crosslinking agent. The polyurethane resin composition according to claim 4, wherein the (E) crosslinking agent is (E1) an aromatic alcohol crosslinking agent and / or (E2) an aliphatic alcohol crosslinking agent. The polyurethane resin composition according to claim 4 or 5, wherein the (E) crosslinking agent is (E1) an aromatic alcohol crosslinking agent. The polyurethane resin composition according to any one of claims 4 to 6, wherein the (E) crosslinking agent is a crosslinking agent having a number average molecular weight of 400 or less. The polyurethane resin composition according to any one of claims 1 to 7, wherein the (D) plasticizer includes (d1) an adipic acid plasticizer and / or (d2) a phthalic acid plasticizer. The polyurethane resin composition according to any one of claims 1 to 8, wherein the (D) plasticizer is (d1) an adipic acid plasticizer. The polyurethane resin composition according to any one of claims 1 to 9, wherein the (D) plasticizer is contained in an amount of 10 to 29% by mass with respect to 100% by mass of the polyurethane resin composition. The polyurethane resin composition according to claim 1, wherein the polyurethane resin composition is used for sealing electrical and electronic parts. The sealing material which consists of a polyurethane resin composition as described in any one of Claims 1-11. An electrical / electronic component sealed with a resin using the sealing material according to claim 12.