JP7592310B2 - Polyurethane resin composition - Google Patents

Description

The present invention relates to a polyurethane resin composition.

The spread of high-capacity, high-speed communications, such as the fifth-generation mobile communications system (5G), has led to an increase in the frequency of signals in communications devices. To achieve high-capacity communications associated with data transmission in the high-frequency band, it is important to keep the dielectric loss (dielectric constant (Dk)/dielectric loss tangent (Df)) of electronic devices low. When polyphenylene ether (PPE) or the like is used as a printed wiring board material, the dielectric loss increases as the frequency increases, because the dielectric constant (Dk) or dielectric loss tangent (Df) is not sufficiently low, resulting in problems such as signal attenuation and heat generation.

The following have been proposed as resins with low dielectric loss (for example, Patent Document 1).
Patent Document 1 describes a curable composition containing polyphenylene ether (PPE) using specific phenols as raw materials.
However, there is no mention at all of the use of a polyurethane resin in the curable composition described in Patent Document 1.

The resin composition described in Patent Document 1 is rigid and requires a high molding temperature of 100°C or higher, limiting its applications.

JP 2020-015909 A

The objective of the present invention is to provide a resin composition that has low dielectric loss in the high frequency band and excellent moldability without adding polyphenylene ether (PPE).

As a result of intensive research into solving the above problems, the inventors have found that the above problems can be solved by forming a polyurethane resin composition in which the polyol compound contains a polyolefin-based polyol. The present invention was completed based on this knowledge.

That is, the present invention relates to the following polyurethane resin composition, etc.

Item 1.
A polyurethane resin composition comprising (A) a polyisocyanate compound and (B) a polyol compound,
The (B) polyol compound contains (B-1) a polyolefin-based polyol,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 2.
Item 2. The polyurethane resin composition according to Item 1, wherein the (B-1) polyolefin-based polyol comprises at least one selected from the group consisting of polyolefin polyols and hydrogenated polyolefin polyols.
Item 3.
Item 3. The polyurethane resin composition according to Item 2, wherein the (B-1) polyolefin-based polyol is a hydrogenated polyolefin polyol.
Item 4.
Item 4. The polyurethane resin composition according to any one of Items 1 to 3, wherein the (A) polyisocyanate compound is an aromatic polyisocyanate compound.
Item 5.
Item 5. The polyurethane resin composition according to item 4, wherein the aromatic polyisocyanate compound is a diphenylmethane diisocyanate compound.
Item 6.
Item 6. The polyurethane resin composition according to item 5, wherein the aromatic polyisocyanate compound is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof.
Item 7.
The polyol compound (B) further contains an ester group-containing polyol (B-2), and
Item 7. The polyurethane resin composition according to any one of items 1 to 6, wherein the ester content in the polyurethane resin composition is less than 9.5%.
Item 8.
Item 8. The polyurethane resin composition according to any one of Items 1 to 7, wherein the (B-2) ester group-containing polyol is a castor oil-based polyol.
Item 9.
Item 9. The polyurethane resin composition according to any one of items 1 to 8, further comprising (C) a plasticizer.
Item 10.
Item 10. The polyurethane resin composition according to item 9, wherein the plasticizer (C) includes at least one selected from the group consisting of ester group-containing plasticizers and hydrocarbon-based plasticizers.
Item 11.
The (C) plasticizer is an ester group-containing plasticizer, and
The ester content in the polyurethane resin composition is less than 9.5%.
Item 11. The polyurethane resin composition according to item 9 or 10.
Item 12.
Item 10. The polyurethane resin composition according to item 9, wherein the plasticizer (C) is a hydrocarbon-based plasticizer.
Item 13.
Item 13. The polyurethane resin composition according to any one of items 1 to 12, further comprising (D) an inorganic filler.
Item 14.
Item 14. The polyurethane resin composition according to item 13, wherein the inorganic filler (D) is fused spherical silica or aluminum hydroxide.
Item 15.
The polyurethane resin composition according to any one of claims 1 to 14, further comprising (H) a crosslinking agent.
Item 16.
Item 16. The polyurethane resin composition according to any one of items 1 to 15, wherein the polyurethane resin composition does not contain polyphenylene ether.
Item 17.
A polyurethane resin composition comprising (A) a polyisocyanate compound and (B) a polyol compound,
The polyurethane resin composition does not contain polyphenylene ether,
The (B) polyol compound contains (B-1) a polyolefin-based polyol,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 18.
A polyurethane resin composition comprising (A) a polyisocyanate compound and (B) a polyol compound,
The polyisocyanate compound (A) is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof,
The (B) polyol compound is a hydrogenated polyolefin polyol,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 19.
A polyurethane resin composition comprising (A) a polyisocyanate compound and (B) a polyol compound,
The polyisocyanate compound (A) is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof,
the (B) polyol compound contains a hydrogenated polyolefin polyol as the (B-1) polyolefin polyol and a castor oil-based polyol as the (B-2) ester group-containing polyol, the content of the (B-1) polyolefin polyol being 20 to 80 parts by mass relative to 100 parts by mass of the (B) polyol compound, and
The content of ester contained in the polyurethane resin composition is less than 9.5%,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 20.
A polyurethane resin composition comprising (A) a polyisocyanate compound, (B) a polyol compound, and (C) a plasticizer,
The polyisocyanate compound (A) is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof,
The (B) polyol compound is a hydrogenated polyolefin polyol,
The (C) plasticizer is an ester group-containing plasticizer, and
The content of ester contained in the polyurethane resin composition is less than 9.5%,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 21.
A polyurethane resin composition comprising (A) a polyisocyanate compound, (B) a polyol compound, and (C) a plasticizer,
The polyisocyanate compound (A) is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof,
The (B) polyol compound is a hydrogenated polyolefin polyol,
The (C) plasticizer is a hydrocarbon-based plasticizer,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 22.
A polyurethane resin composition comprising (A) a polyisocyanate compound, (B) a polyol compound, (C) a plasticizer, and (D) an inorganic filler,
The polyisocyanate compound (A) is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof,
The (B) polyol compound is a hydrogenated polyolefin polyol,
The (C) plasticizer is an ester group-containing plasticizer, and
The content of ester contained in the polyurethane resin composition is less than 9.5%,
The inorganic filler (D) is fused spherical silica or aluminum hydroxide,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 23.
A polyurethane resin composition comprising (A) a polyisocyanate compound, (B) a polyol compound, (C) a plasticizer, and (D) an inorganic filler,
The polyisocyanate compound (A) is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof,
The (B) polyol compound is a hydrogenated polyolefin polyol,
The (C) plasticizer is a hydrocarbon-based plasticizer,
The inorganic filler (D) is fused spherical silica or aluminum hydroxide,
A polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less.
Item 24.
24. The polyurethane resin composition according to any one of items 1 to 23, which is used for sealing electric and electronic parts.
Item 25.
Item 25. An encapsulant comprising the polyurethane resin composition according to any one of items 1 to 24.
Item 26.
Item 26. An electric/electronic component resin-sealed with the sealing material according to item 25.
Item 27.
Item 25. An electronic part comprising the polyurethane resin composition according to any one of items 1 to 24.
Item 28.
Item 25. An adhesive comprising the polyurethane resin composition according to any one of items 1 to 24.
Item 29.
Item 25. A coating agent comprising the polyurethane resin composition according to any one of items 1 to 24.

The present invention provides a resin composition that has low dielectric loss in the high frequency band and excellent moldability.

Specifically, the polyurethane resin composition of the present invention has a polyol compound containing a polyolefin polyol, a relative dielectric constant of 3.0 or less at 10 GHz, and a dielectric loss tangent of 0.01 or less, so that the dielectric loss in the high frequency band is small. In addition, because it is a polyurethane resin composition, it has excellent moldability compared to conventionally used polyphenylene ethers, etc.

The polyurethane resin composition of the present invention will be described in detail below. In this specification, the expressions "contain" and "comprise" include the concepts of "contain," "comprise," "consist essentially of," and "consist only of."

1. Polyurethane resin composition The polyurethane resin composition of the present invention is a polyurethane resin composition containing (A) a polyisocyanate compound and (B) a polyol compound,
The (B) polyol compound contains (B-1) a polyolefin-based polyol,
The relative dielectric constant is 3.0 or less, and the dielectric loss tangent is 0.01 or less.

The resin composition obtained by curing the polyurethane resin composition of the present invention exhibits low dielectric properties, such as a low relative dielectric constant and/or a low dielectric loss tangent, in the high frequency band, and therefore has low dielectric loss in the high frequency band.
In this specification, a high frequency is equal to or higher than 1 GHz, preferably 3 GHz to 80 GHz, and more preferably 5 GHz to 72 GHz.
Specifically, the polyurethane resin composition of the present invention has a relative dielectric constant at 10 GHz of 3.0 or less, preferably 2.5 or less, and more preferably 2.3 or less. The lower limit of the relative dielectric constant is preferably as close to 0 as possible.
The polyurethane resin composition of the present invention has a dielectric loss tangent at 10 GHz of 0.01 or less, preferably 0.005 or less, and more preferably 0.003 or less. The lower limit of the dielectric loss tangent is preferably as close to 0 as possible.
The polyurethane resin composition of the present invention can exhibit low dielectric properties even without containing polyphenylene ether (PPE).

1-1. (A) Polyisocyanate Compound The "(A) polyisocyanate compound" is not particularly limited as long as it has two or more isocyanate groups, and various components that are used or can be used in polyurethane resin compositions can be used.

The polyisocyanate compound (A) is not particularly limited and may be, for example,
(A1) an aliphatic polyisocyanate compound,
(A2) an alicyclic polyisocyanate compound,
(A3) polyisocyanate compounds such as aromatic polyisocyanate compounds;
The modified polyisocyanate compound (a) (e.g.,
(a-1) an isocyanurate compound,
(a-2) a carbodiimide compound,
(a-3) adduct,
(a-4) biuret form,
(a-5) allophanate, etc.);
The polynuclear derivative (b) of the polyisocyanate compound is also included.

(A1) Examples of aliphatic polyisocyanate compounds include tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, and 3-methylpentane-1,5-diisocyanate, with 1,6-hexamethylene diisocyanate (HDI) being preferred.

In addition, the aliphatic polyisocyanate compound (A1) is preferably an isocyanurate of an aliphatic polyisocyanate compound (A1a-1). For example, in the present invention, an isocyanurate compound having an isocyanate group at its terminal, which is derived from 1,6-hexamethylene diisocyanate (hereinafter abbreviated as "HDI"), can be used as the isocyanurate-modified 1,6-hexamethylene diisocyanate. Specific examples of these include Duranate (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TSE-100, and TLA-100 manufactured by Asahi Kasei Corporation; Desmodur (registered trademark) N3390 manufactured by Sumitomo Bayer Urethane Co., Ltd.; Coronate (registered trademark) EH manufactured by Nippon Polyurethane Co., Ltd.; Takenate D170N manufactured by Takeda Pharmaceutical Co., Ltd.; and Burnock (registered trademark) DN980 manufactured by Dainippon Ink and Chemicals, Inc. (DIC Corporation).

(A2) Examples of 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, and 1,3-bis(isocyanatomethyl)cyclohexane.

The hydrogenated product of 4,4'-diphenylmethane diisocyanate used in the present invention is a polyisocyanate obtained by hydrogenating 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as MDI). A specific example of this is WANNATE (registered trademark) HMDI manufactured by Wanka Chemical Japan.

(A3) Examples of aromatic polyisocyanate compounds 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, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α,α,α,α-tetramethylxylylene diisocyanate, and the like, and preferred are 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate (MDI). A specific example of this is Millionate (registered trademark) MR-200 (a mixture of MDI and its polynuclear derivatives) manufactured by Tosoh Corporation.

(A3) An example of the modified aromatic polyisocyanate compound (a) is the (a-2) carbodiimide derivative of 4,4'-diphenylmethane diisocyanate (MDI). In the present invention, a polyisocyanate having a carbodiimide group derived from 4,4'-diphenylmethane diisocyanate (carbodiimide-modified MDI) can be used. A specific example of this is Millionate (registered trademark) MTL manufactured by Tosoh Corporation.

The viscosity of the (A) polyisocyanate compound varies depending on the type of polyisocyanate compound and whether it is modified or not, but is not particularly limited. For example, in the case of aromatic polyisocyanate compounds and their modified products and polynuclear products (preferably carbodiimide and polynuclear products of aromatic polyisocyanate compounds), the viscosity is, for example, 5 to 200 mPa·s, preferably 10 to 150 mPa·s, more preferably 15 to 100 mPa·s, and even more preferably 20 to 80 mPa·s at 25°C. As another example, in the case of aliphatic polyisocyanate compounds and their modified products and polynuclear products (preferably isocyanurate products of aliphatic polyisocyanate compounds), the viscosity is, for example, 100 to 3000 mPa·s, preferably 500 to 2500 mPa·s, more preferably 1000 to 2000 mPa·s, and even more preferably 1200 to 1700 mPa·s at 25°C.

The NCO content of the (A) polyisocyanate compound is not particularly limited, but is, for example, 15 to 45%, more preferably 20 to 40%, and even more preferably 20 to 35%.

As the (A) polyisocyanate compound, from the viewpoint of being able to further reduce the relative dielectric constant and the dielectric loss tangent, preferably, (Aa-1) an isocyanurate of a polyisocyanate compound (more preferably, (A1a-1) an isocyanurate of an aliphatic polyisocyanate compound),
(A3) an aromatic polyisocyanate compound (more preferably, 4,4'-diphenylmethane diisocyanate (MDI) or a polynuclear product of MDI, and a mixture of MDI and a polynuclear product of MDI);
(A3) A carbodiimide derivative of an aromatic polyisocyanate compound (more preferably, a polyisocyanate having a carbodiimide group derived from 4,4'-diphenylmethane diisocyanate (carbodiimide-modified MDI)) can be mentioned.

As the (A) polyisocyanate compound, 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof is more preferable, and specifically,
(A3) An aromatic polyisocyanate compound (more preferably, 4,4'-diphenylmethane diisocyanate (MDI) or a polynuclear MDI, and a mixture of MDI and a polynuclear MDI) and a carbodiimide-modified product of 4,4'-diphenylmethane diisocyanate, i.e., a polyisocyanate having a carbodiimide group derived from 4,4'-diphenylmethane diisocyanate (carbodiimide-modified MDI) are more preferred.

Among these, preferred commercially available polyisocyanate compounds (A) include, for example, Duranate (registered trademark) TPA-100 (manufactured by Asahi Kasei Corporation), Millionate (registered trademark) MR-200 (manufactured by Tosoh Corporation), and Millionate (registered trademark) MTL (manufactured by Tosoh Corporation), with Millionate (registered trademark) MR-200 (manufactured by Tosoh Corporation) and Millionate (registered trademark) MTL (manufactured by Tosoh Corporation) being more preferred.

(A) The polyisocyanate compound may be used alone or in any combination of two or more.

The content of the (A) polyisocyanate compound is not particularly limited as long as it is an amount that can be used in the polyurethane resin composition. The content is, for example, usually 0.01 to 50 mass%, preferably 0.1 to 35 mass%, more preferably 1 to 30 mass%, and particularly preferably 1.5 to 25 mass%, based on 100 mass% of the polyurethane resin composition.
The content of the polyisocyanate compound (A) relative to 100 parts by mass of the polyol compound (B) is, for example, 5 to 75 parts by mass, preferably 8 to 70 parts by mass, and more preferably 10 to 65 parts by mass.

When two or more types of (A) polyisocyanate compounds are blended in the polyurethane resin composition of the present invention, the total amount can be adjusted according to the content of the above-mentioned (A) polyisocyanate compound.

When the polyurethane resin composition of the present invention contains the aromatic polyisocyanate compound (A3), the content thereof is usually 0.01 to 50 mass%, preferably 0.1 to 35 mass%, and more preferably 1 to 30 mass%, relative to 100 mass% of the polyurethane resin composition.

The amount of the polyisocyanate compound (A) and the polyol compound (B) described below is in such a range 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 total of the polyol compounds, is 0.5 to 1.5, preferably 0.7 to 1.3, and more preferably 0.8 to 1.1.

1-2. (B) Polyol Compound The (B) polyol compound used in the present invention includes (B-1) a polyolefin polyol. (B-1) Polyolefin polyol is, for example, a polymer of a radically polymerizable monomer having two or more unsaturated double bonds, or a copolymer of such a radically polymerizable monomer and another radically polymerizable monomer, and has two or more hydroxyl groups.

(B-1) Polyolefin polyols include polyolefin polyols (e.g., polybutadiene polyols, polyisoprene polyols) and hydrogenated polyolefin polyols (hydrogenated polyolefin polyols), etc.

Examples of polyolefin polyols include polybutadiene polyols and polyisoprene polyols. Commercially available polyolefin polyols include polybutadiene polyols [Nisso-PBG series (G-1000, G-2000, G-3000, etc.) manufactured by Nippon Soda Co., Ltd., Poly Bd (registered trademark) series (R-45M, R-45HT, CS-15, CN-15, etc.) manufactured by ARCO Corporation of the United States], and polyisoprene polyols [Poly ip manufactured by Idemitsu Kosan Co., Ltd.].

Examples of hydrogenated polyolefin polyols (hydrogenated polyolefin polyols) include hydrogenated polybutadiene polyols and hydrogenated polyisoprene polyols. Commercially available hydrogenated polyolefin polyols include hydrogenated polybutadiene polyols (NISSO-PBGI series (GI-1000, GI-2000, GI-3000, etc.) manufactured by Nippon Soda Co., Ltd.), hydrogenated polyolefin polyols (Epole manufactured by Idemitsu Kosan Co., Ltd.), etc.

The hydroxyl value of the polyolefin polyol (B-1) is preferably 1 to 120 mgKOH/g, more preferably 10 to 90 mgKOH/g, and particularly preferably 25 to 80 mgKOH/g.

The hydroxyl group content of the polyolefin polyol (B-1) is not particularly limited, but is usually 0.001 to 3 mol/kg, preferably 0.01 to 2 mol/kg, and more preferably 0.1 to 1.2 mol/kg.

The number average molecular weight (Mn) of the polyolefin polyol (B-1) 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.

The viscosity of the polyolefin polyol (B-1) (30° C.) is usually in the range of 0.01 to 500 Pa·s, preferably in the range of 0.1 to 300 Pa·s, and more preferably in the range of 1 to 150 Pa·s.
do.

The iodine value of the polyolefin polyol (B-1) is usually in the range of 1 to 1000 g/100 g, preferably in the range of 5 to 500 g/100 g, and more preferably in the range of 10 to 100 g/100 g.
do.

The polyolefin polyol (B-1) may be used alone or in combination of two or more kinds.
Among these, the polyolefin polyol (B-1) is preferably a polyolefin polyol or a hydrogenated polyolefin polyol having a side chain structure (substituent) containing at least one selected from the group consisting of a methyl group, an ethyl group, an isopropyl group, and a vinyl group, a repeating unit containing the side chain structure being a 15-45-mer, and a hydroxyl value of 80 mgKOH/g or less.
As the polyolefin polyol (B-1), hydrogenated polyolefin polyols are more preferred, and hydrogenated polybutadiene polyols are particularly preferred.
As commercially available hydrogenated polyolefin polyols, hydrogenated polybutadiene polyols ("NISSO-PBGI series" GI-1000, manufactured by Nippon Soda Co., Ltd.) and hydrogenated polyolefin polyols ("EPOL", manufactured by Idemitsu Kosan Co., Ltd.) are preferably used.

The (B) polyol compound used in the present invention may further contain (B-2) an ester group-containing polyol.

(B-2) Examples of ester group-containing polyols include castor oil-based polyols and polyester polyols other than the castor oil-based polyols.

There are no particular limitations on the castor oil-based polyol, and examples include castor oil and castor oil derivatives.

Examples of the castor oil derivatives include castor oil fatty acid; hydrogenated castor oil obtained by hydrogenating castor oil or castor oil fatty acid; transesterification products of castor oil and other fats and oils; reaction products of castor oil and polyhydric alcohol; esterification products of castor oil fatty acid and polyhydric alcohol; and compounds obtained by addition polymerization of these with alkylene oxide. Of the castor oil-based polyols, it is preferable to use castor oil.

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

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

The castor oil-based polyol preferably has an average hydroxyl value, determined in accordance with JIS K1557-1, of 20 to 250 mgKOH/g, and more preferably 50 to 200 mgKOH/g.

The ester group-containing polyol other than the castor oil-based polyol is not particularly limited, and examples thereof include polyols obtained by an esterification reaction between a polyol component and an acid component.

The polyol component is not particularly limited, and examples thereof include 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, and polypropylene glycol.

The acid component is not particularly limited, and examples thereof include succinic acid, methylsuccinic 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, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and anhydrides thereof.

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

(B-2) As the ester group-containing polyol, castor oil-based polyol is preferred. Commercially available castor oil-based polyols include URIC H-35 manufactured by Ito Oil Mills Co., Ltd.

The (B) polyol compound used in the present invention may further contain a polyol compound other than the above (B-1) polyolefin polyol and (B-2) ester group-containing polyol (hereinafter referred to as "(B-3) polyol").

(B-3) Examples of polyols include dimer acid polyols; polyether polyols; polyester polyols; polycarbonate polyols; polycaprolactone polyols; acrylic polyols; and hydrogenated versions of these.

There are no particular limitations on the dimer acid polyol, and any known dimer acid polyol can be used.

The polyether polyol is not particularly limited, and examples thereof include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide using water, low molecular weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcin, hydroquinone, etc.) as initiators. Specific examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

The polycarbonate polyol is not particularly limited, and examples thereof include polycarbonate polyols obtained by polycondensation reaction of the above polyol components with phosgene; polycarbonate polyols obtained by transesterification condensation of the above polyol components with carbonate diesters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, 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 esterification reaction of the above polycarbonate polyols with a carboxyl group-containing compound; Examples of the polycarbonate polyol include polycarbonate polyols obtained by etherification reaction of the various polycarbonate polyols with hydroxyl group-containing compounds; polycarbonate polyols obtained by transesterification reaction of the various polycarbonate polyols with ester compounds; polycarbonate polyols obtained by transesterification reaction of the various polycarbonate polyols with hydroxyl group-containing compounds; polyester-based polycarbonate polyols obtained by polycondensation reaction of the various polycarbonate polyols with dicarboxylic acid compounds; copolymerized polyether-based polycarbonate polyols obtained by copolymerizing the various polycarbonate polyols with alkylene oxides. The polycarbonate polyols can be referred to as polycarbonate diols.

There are no particular limitations on the polycaprolactone polyol, and examples include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and δ-valerolactone.

Examples of acrylic polyols include copolymers obtained by copolymerizing a hydroxyl group-containing acrylate with a copolymerizable vinyl monomer that is copolymerizable with the hydroxyl group-containing acrylate.

Examples of hydroxyl group-containing acrylates include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, 2,2-dihydroxymethylbutyl (meth)acrylate, polyhydroxyalkyl maleate, polyhydroxyalkyl fumarate, etc., and preferably 2-hydroxyethyl (meth)acrylate, etc.

Examples of the copolymerizable vinyl monomer include alkyl (meth)acrylates (having 1 to 12 carbon atoms) such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, isononyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl acrylate;
For example, aromatic vinyls such as styrene, vinyl toluene, and α-methyl styrene;
For example, vinyl cyanides such as (meth)acrylonitrile;
For example, vinyl monomers containing a carboxyl group, such as (meth)acrylic acid, fumaric acid, maleic acid, itaconic acid, etc., or alkyl esters thereof;
For example, alkane polyol poly(meth)acrylates such as ethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, oligoethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, and trimethylolpropane tri(meth)acrylate;
For example, vinyl monomers containing an isocyanate group such as 3-(2-isocyanate-2-propyl)-α-methylstyrene can be mentioned.

Acrylic polyols can be obtained by copolymerizing these hydroxyl group-containing acrylates and copolymerizable vinyl monomers in the presence of a suitable solvent and polymerization initiator.

Acrylic polyols include, for example, silicone polyols and fluorine polyols.

Examples of silicone polyols include acrylic polyols blended with a silicone compound containing a vinyl group, such as γ-methacryloxypropyltrimethoxysilane, as a copolymerizable vinyl monomer in the copolymerization of the acrylic polyol described above.

Examples of fluorine polyols include acrylic polyols blended with fluorine compounds containing vinyl groups, such as tetrafluoroethylene and chlorotrifluoroethylene, as copolymerizable vinyl monomers in the copolymerization of the acrylic polyols described above.

The vinyl monomer modified polyol can be obtained by reacting the above-mentioned high molecular weight polyol with a vinyl monomer.

As the polyol compound (B), the polyolefin polyol (B-1) can be used alone, or the polyolefin polyol (B-1) and the ester group-containing polyol (B-2) can be mixed. As the polyolefin polyol (B-1), two or more kinds of polyolefin polyols (B-1) having different molecular weights can be used, or a polyolefin polyol and a hydrogenated polyolefin polyol can be mixed. In addition, a polyol compound (B-3) other than the above (B-1) and (B-2) can be blended. When the polyol compound (B-3) is blended, one kind can be used alone, or two or more kinds can be mixed.

The polyurethane resin composition of the present invention contains (B-1) a polyolefin polyol as a hydroxyl group-containing compound, which allows the relative dielectric constant and/or dielectric tangent of the polyurethane resin composition to be reduced.

The content of (B-1) polyolefin polyol is preferably 20 to 100 parts by mass, more preferably 50 to 100 parts by mass, and even more preferably 80 to 100 parts by mass, per 100 parts by mass of (B) polyol compound.

When the polyurethane resin composition of the present invention contains an ester group-containing compound, the ester content in the polyurethane resin composition is preferably less than 9.5%, and more preferably 5% or less.

Here, the ester group-containing compound may be a compound (monomer) or a polymer, so long as it contains an ester group (COO group). Examples of ester group-containing compounds include polyols (ester group-containing polyols), prepolymers (prepolymers obtained by reacting isocyanates with ester group-containing polyols), and plasticizers (ester group-containing plasticizers) described below.

When the polyurethane resin composition of the present invention contains a polyol as an ester group-containing compound, i.e., when the (B) polyol compound contains (B-2) an ester group-containing polyol, the ester content in the polyurethane resin composition is preferably less than 9.5%, and more preferably 6% or less.

When the ester group-containing compound is an ester group-containing polyol, the ester content in the polyurethane resin composition is a value calculated according to the following formula (1).

The ester mass (%) in formula (1) represents the mass (%) of ester groups per molecule of ester group-containing polyol, and can be calculated using the following formula (2).

When the polyurethane resin composition of the present invention contains only two components, that is, (A) a polyisocyanate compound and (B) a polyol compound, it is preferable that the (B) polyol compound contains only (1) (B-1) a polyolefin-based polyol, or contains (2) (B-1) a polyolefin-based polyol and (B-2) an ester group-containing polyol.
When the polyurethane resin composition of the present invention contains, as the polyol compound (B), a polyolefin-based polyol (B-1) and an ester group-containing polyol (B-2), the content of the polyolefin-based polyol (B-1) is preferably 20 to 95 parts by mass, and more preferably 25 to 80 parts by mass, per 100 parts by mass of the polyol compound (B) (the total amount of the polyolefin-based polyol (B-1) and the ester group-containing polyol (B-2)).

1-3. (C) Plasticizer The polyurethane resin composition of the present invention may further contain (C) a plasticizer, if necessary.

The plasticizer (C) used in the present invention is not particularly limited, and examples thereof include ester group-containing plasticizers and hydrocarbon-based plasticizers.

Examples of ester group-containing plasticizers include phthalate ester plasticizers such as dioctyl phthalate, diisononyl phthalate (diisononyl phthalate), and diundecyl phthalate; adipate ester plasticizers such as dioctyl adipate, diisononyl adipate, and diisodecyl adipate; castor oil ester plasticizers such as methyl acetyl ricinoleate, butyl acetyl ricinoleate, acetylated ricinoleic acid triglyceride, and acetylated polyricinoleic acid triglyceride; trimellitic acid esters such as trioctyl trimellitate and triisononyl trimellitate; and pyromellitic acid ester plasticizers such as tetraoctyl pyromellitate and tetraisononyl pyromellitate.

Examples of hydrocarbon plasticizers include olefinic hydrocarbons such as ethylene and α-olefin co-oligomers, poly-α-olefins, and hydrogenated poly-α-olefins, paraffinic hydrocarbons, naphthenic hydrocarbons, and mixed paraphene-naphthenic hydrocarbons.

Among these, hydrocarbon plasticizers are preferred, and olefin plasticizers are more preferred.

When the polyurethane resin composition of the present invention contains a plasticizer (C), the content of the plasticizer (C) is preferably 0.01 to 50 mass%, more preferably 0.1 to 30 mass%, and particularly preferably 1 to 20 mass%, relative to 100 mass% of the polyurethane resin composition.

In particular, when the polyurethane resin composition of the present invention contains a plasticizer as an ester group-containing compound, i.e., when the polyurethane resin composition contains an ester group-containing plasticizer as a plasticizer, the lower limit of the ester content in the polyurethane resin composition is preferably 0.1% or more, and particularly preferably 1% or more. The upper limit of the ester content in the polyurethane resin composition is preferably less than 9.5%, more preferably 6% or less, and particularly preferably 5% or less.
Here, when the ester group-containing compound is an ester group-containing plasticizer, the ester content in the polyurethane resin composition is a value calculated according to the following formula (3).

The ester mass (%) in formula (3) represents the mass (%) of ester groups per molecule of the ester group-containing plasticizer, and can be calculated using the following formula (4).

When two or more kinds of ester group-containing compounds are contained, the ester content of each ester group-containing compound can be calculated separately and the obtained values can be added together to determine the ester content.
When the polyurethane resin composition of the present invention contains both an ester group-containing polyol and an ester group-containing plasticizer as the ester group-containing compound, it is preferable that the respective ester contents are calculated separately and the total ester content is less than 9.5%.

The above (C) plasticizers can be used alone or in combination of two or more.

When the polyurethane resin composition of the present invention is composed of three components, namely (A) a polyisocyanate compound, (B) a polyol compound, and (C) a plasticizer, it is preferable that (B) the polyol compound contains only (B-1) a polyolefin-based polyol and does not contain (B-2) an ester group-containing polyol.

1-4. (D) Inorganic Filler (D) An inorganic filler can be added to the polyurethane resin composition of the present invention within a range that does not lower or have no effect on the relative dielectric constant and/or dielectric tangent.

The inorganic filler (D) used in the present invention is not particularly limited, and examples thereof include metal hydroxides, metal oxides, metal nitrides, zeolites, etc. Furthermore, the surface of the metal oxides, etc. may be treated. Examples of methods for treating the surface of the metal oxides, etc. include oxidation treatment and treatment with a surface treatment agent such as a silane coupling agent.

Examples of metal hydroxides include aluminum hydroxide and magnesium hydroxide. Here, aluminum hydroxide and magnesium hydroxide also act as flame retardants.

Examples of metal oxides include aluminum oxide (alumina), magnesium oxide, silicon dioxide (silica, etc.), titanium oxide, etc.

Examples of metal nitrides include boron nitride, aluminum nitride, and silicon nitride.

There are no particular limitations on the zeolite, and any zeolite used in known polyurethane resin compositions can be used.

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

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

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

Preferred inorganic fillers are metal hydroxides and metal oxides, more preferably aluminum hydroxide, aluminum oxide (alumina), and silicon dioxide (silica), and particularly preferably fused silica.

The inorganic filler (D) may be used alone or in combination of two or more.

When the polyurethane resin composition of the present invention contains an inorganic filler (D), the content of the inorganic filler (D) is usually preferably 1 to 85% by mass, more preferably 5 to 70% by mass, and particularly preferably 20 to 60% by mass, based on 100% by mass of the polyurethane resin composition.

The shape of the inorganic filler (D) is not particularly limited and may be any of spherical, hollow, irregular, etc., with spherical being preferred. As the inorganic filler (D), spherical fused silica (fused spherical silica) can be particularly preferably used.
The average particle diameter (D50) of the inorganic filler (D) is, for example, 0.001 μm to 100 μm, preferably 0.01 μm to 50 μm, and more preferably 0.1 μm to 30 μm. The average particle diameter (D50) is measured by a laser diffraction scattering type particle size distribution measurement method.

When the polyurethane resin composition of the present invention is composed of four components, namely (A) a polyisocyanate compound, (B) a polyol compound, (C) a plasticizer, and (D) an inorganic filler, it is preferable that (B) the polyol compound contains only (1) (B-1) a polyolefin-based polyol and does not contain (B-2) an ester group-containing polyol.

1-5. (E) Defoaming Agent The polyurethane resin composition of the present invention may further contain (E) an antifoaming agent, if necessary.

The defoaming 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, etc.

The preferred silicone-based defoaming agent is a modified silicone-based defoaming agent (especially one in which polysiloxane is modified with a hydrophilic group, with the lipophilic group being polysiloxane).

The above (E) defoaming agent can be used alone or in a mixture of two or more types.

When (E) an antifoaming agent is contained, its content is not particularly limited, but is preferably 0.001 to 10 mass% and more preferably 0.005 to 5 mass% relative to 100 mass% of the polyurethane resin composition.

1-6. (F) Polymerization catalyst The polyurethane resin composition of the present invention may further contain (F) a polymerization catalyst, if necessary. By using (F) a polymerization catalyst, the reactivity of the isocyanate compound (particularly, HDI-based isocyanate having low activity) can be increased, and the number of unreacted hydroxyl groups can be reduced, thereby decreasing the relative dielectric constant and/or the dielectric loss tangent.

(F) As the polymerization catalyst, known polymerization catalysts can be used, for example, metal catalysts such as organotin catalysts, organolead catalysts, and organobismuth catalysts; amine catalysts, etc.

Examples of organotin catalysts include dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, and dioctyltin diacetate.

Examples of organic lead catalysts include lead octoate, lead octenate, and lead naphthenate.

Examples of organic bismuth catalysts include bismuth octoate and bismuth neodecanoate.

Examples of amine catalysts include diethylenetriamine, triethylamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, trimethylenediamine, dimethylaminoethanol, bis(2-dimethylaminoethyl)ether, and the like. In addition, organometallic compounds, metal complex compounds, and the like may also be used as the catalyst.

When (F) a polymerization catalyst is contained, its content may be within a range that does not impair workability. For example, it is preferably 0.00001 to 10 mass%, more preferably 0.0001 to 5 mass%, and even more preferably 0.001 to 1 part by mass relative to 100 mass% of the polyurethane resin composition.

The above (F) polymerization catalyst can be used alone or in combination of two or more.

1-7. (G) Flame Retardant The polyurethane resin composition of the present invention may further contain (G) a flame retardant.
(G) Examples of the flame retardant include inorganic flame retardants, bromine-based flame retardants, chlorine-based flame retardants, and phosphorus-based flame retardants.
As the inorganic flame retardant, in addition to aluminum hydroxide, magnesium hydroxide, alumina, magnesium oxide, and silica described above as the inorganic filler, for example, antimony trioxide, antimony pentoxide, ammonium borate, etc. can be used.
Examples of bromine-based flame retardants include hexabromobenzene, decabromodiphenyl oxide (DBDPO), tetrabromobisphenol A (TBBA), and ethylenebis(pentabromophenyl).
Examples of chlorine-based flame retardants include chlorinated paraffin, perchlorocyclopentadecanone, and chlorendic acid.
Examples of phosphorus-based flame retardants include triphenyl phosphate (TPP), tricresyl phosphate (TCP), trixylenyl phosphate (TXP), and cresyl diphenyl phosphate (CDP).

When the polyurethane resin composition of the present invention contains a flame retardant (G), the content of the flame retardant (G) is usually preferably 5 to 85% by mass, more preferably 10 to 70% by mass, and particularly preferably 20 to 60% by mass, relative to 100% by mass of the polyurethane resin composition.

1-8. (H) Crosslinking agent (chain extender)
The polyurethane resin composition of the present invention may further contain (H) a crosslinking agent (also known as a chain extender).
The (H) crosslinking agent is not particularly limited, and examples thereof include (H1) aromatic alcohol crosslinking agents such as N,N-bis(2-hydroxypropyl)aniline, hydroquinone-bis(β-hydroxyethyl)ether, and resorcinol-bis(β-hydroxyethyl)ether;
(H2) Aliphatic alcohol-based crosslinking agents such as ethylene glycol, 1,3-butanediol (1,3-butylene glycol), 1,4-butanediol, octanediol, trimethylolpropane, and triisopropanolamine;
(H3) aromatic amine-based crosslinking agents such as phenylenediamine, tolylenediamine, diphenyldiamine, 4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 1,2-bis(2-aminophenylthio)ethane, and trimethylene glycol-p-aminobenzoate;
Examples of the crosslinking agent include (H4) aliphatic amine-based crosslinking agents such as ethylenediamine, propylenediamine, hexamethylenediamine, and diethylenetriamine.

Among these, (H1) aromatic alcohol-based crosslinking agent and (H2) aliphatic alcohol-based crosslinking agent are preferred, and (H2) aliphatic alcohol-based crosslinking agent is more preferred.

The number average molecular weight of the crosslinking agent (H) is usually 1,000 or less, preferably 500 or less, and more preferably 400 or less.

When the polyurethane resin composition of the present invention contains a crosslinking agent (H), the content of the crosslinking agent (H) is not particularly limited, and is, for example, usually 0.01 to 30% by mass, preferably 1 to 20% by mass, and more preferably 2 to 15% by mass, relative to 100% by mass of the polyurethane resin composition.

The above-mentioned (H) crosslinking agent may be used alone or in combination of two or more kinds.
As the (H) crosslinking agent, among the (H2) aliphatic alcohol crosslinking agents, short-chain diols having a number average molecular weight of 500 or less (for example, ethylene glycol, 1,3-butanediol, 1,4-butanediol, octanediol, etc.) can be preferably used.

1-9. Other Components The polyurethane resin composition of the present invention may further contain various additives, such as antioxidants, tackifiers, curing accelerators, colorants, fillers, pigments, bulking agents, urethanization catalysts, ultraviolet absorbers, moisture absorbents, antifungal agents, and silane coupling agents, as necessary.

The content of these components may be appropriately determined based on the usual amounts added and the ranges of their identification, depending on the intended use, so as not to impair the desired properties of the polyurethane resin composition.

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

Examples of such a production method include a method including a step (step 1) of preparing (A) a composition (first component) containing a polyisocyanate compound, a step (step 2) of preparing (B) a composition (second component) containing a polyol compound, and a step (step 3) of mixing the second component with the first component to obtain a polyurethane resin composition.

As long as the first component (agent I) contains (A) a polyisocyanate compound and the second component (agent II) contains (B) a polyol compound, the other components may be contained in either the second component or the first component.

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

The second component (agent II) may contain other components in addition to the polyol compound (B).

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

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

Specifically, the (X) urethane prepolymer is obtained by reacting components including (A) a polyisocyanate compound and (B) a polyol compound. The (X) urethane prepolymer includes not only urethane prepolymers obtained by reacting materials consisting of the (A) and (B) components, but also urethane prepolymers obtained by reacting the (A) and (B) components with optional components, etc., and may also contain other components as described above.

More specifically, the polyurethane resin composition of the present invention may have a structure in which the first component contains a polyisocyanate compound (A) and a plasticizer (C), and the second component contains a polyol compound (B) and an inorganic filler (D);
A structure in which the first component contains (A) a polyisocyanate compound, and the second component contains (B) a polyol compound, (C) a plasticizer, and (D) an inorganic filler;
An example of the composition includes a first component containing a polyisocyanate compound (A) and a plasticizer (C), and a second component containing a polyol compound (B), a plasticizer (C), and an inorganic filler (D).

The first component contains a polyisocyanate compound (A) and an inorganic filler (D), and the second component contains a polyol compound (B);
A configuration in which the first component contains (A) a polyisocyanate compound and (C) a plasticizer, and the second component contains (B) a polyol compound, (C) a plasticizer, and (D) an inorganic filler;
A structure in which the first component contains (A) a polyisocyanate compound and (C) a plasticizer, and the second component contains (B) a polyol compound, (C) the plasticizer, (D) an inorganic filler, and (E) an antifoaming agent;
The first component may contain (A) a polyisocyanate compound and (C) a plasticizer, and the second component may contain (B) a polyol compound, (C) a plasticizer, (D) an inorganic filler, (E) an antifoaming agent, and (F) a polymerization catalyst.
In addition, when the polyurethane resin composition of the present invention further contains a flame retardant (G) and/or a crosslinking agent (H), the flame retardant (G) and the crosslinking agent (H) may be blended in either the first component or the second component.

When producing a polyurethane resin composition, the first component (agent I) is usually used in an amount of 1 to 1,000 parts by mass, preferably 3 to 100 parts by mass, and more preferably 5 to 25 parts by mass, per 100 parts by mass of the second component (agent II).
The reason for blending other components with the first component is to lower the viscosity of the polyisocyanate compound and to match the ratio (blending ratio) of the first component and the second component. Therefore, the first component can be used without blending other components. If necessary, the first component or the second component may be diluted with an organic solvent (e.g., toluene, methyl ethyl ketone, butyl acetate, etc.) or water before mixing, or the first component and the second component may be mixed and then diluted with the organic solvent or water. Diluting with an organic solvent or water reduces the viscosity of each agent, improving workability.

In the polyurethane resin composition, the (A) polyisocyanate compound and the (B) polyol compound may react partially or completely to form a polyurethane resin. That is, the polyurethane resin composition may be in a liquid state before curing, or may be cured. The polyurethane resin composition may be cured over time by mixing the first and second components, causing the (A) polyisocyanate compound and the (B) polyol compound to react to form a polyurethane resin, but it may also be cured 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. Applications The polyurethane resin composition of the present invention has low dielectric loss in the high frequency band and excellent moldability, and therefore can be suitably used as an adhesive for flexible substrates and multi-layer substrates, as a surface coating agent, etc.

The polyurethane resin composition of the present invention will be specifically described below with reference to examples and comparative examples. However, the examples are merely illustrative, and the present invention is not limited to the examples.

The raw materials used in the examples and comparative examples are listed below.

<(A) Polyisocyanate Compound>
A1: MTL
Product name: Millionate MTL (registered trademark) (carbodiimide-modified MDI), manufactured by Tosoh Corporation A2: TPA-100
Product name: Duranate (registered trademark) TPA-100 (HDI isocyanurate modified product), manufactured by Asahi Kasei Corporation

<(B) Polyol Compound>
(B-1) Polyolefin polyol b1: R-15HT
Product name: Poly bd (registered trademark) R-15 HT, manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight 1200, hydroxyl value 102.7 mg KOH/g (JIS K 1557), iodine value 420 g/100 g (JIS K 0070), viscosity 1.5 Pa·S/30°C (JIS K 2283)
b2: R-45HT
Product name: Poly bd (registered trademark) R-45 HT, manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight 2800, hydroxyl value 46.6 mg KOH/g (JIS K 1557), iodine value 398 g/100 g (JIS K 0070), viscosity 5 Pa·S/30°C (JIS K 2283)
b3: Epol
Product name: EPOL (registered trademark) manufactured by Idemitsu Kosan Co., Ltd. (hydrogenated polyolefin polyol), number average molecular weight 2500, hydroxyl value 50 mg KOH/g (JIS K 1557), iodine value 5 g/100 g or less (JIS K 0070)
b4: GI-1000
Product name: NISSOPB GI-1000, manufactured by Nippon Soda Co., Ltd. (hydrogenated polybutadiene polyol), number average molecular weight 1500, hydroxyl value 67 mg KOH/g (JIS K 1557), iodine value 21 g/100 g or less (JIS K 0070)
(B-2) Ester group-containing polyol b5: H-35 (castor oil-based polyol)
Product name: URIC H-35, manufactured by Ito Oil Mills Co., Ltd. (castor oil-based polyol for polyurethane), molecular weight: 933, hydroxyl value: 159 mg KOH/g (JIS K 1557), number of ester groups: 3, ester mass (mass% of ester groups per molecule): 14%
(B-3) Other polyols b6: GP-3000 (polyether polyol)
Product name: Sannix GP-3000, manufactured by Sanyo Chemical Industries, Ltd. (polyether polyol), number average molecular weight 3000, hydroxyl value 56 mg KOH/g (JIS K 1557)
b7: PH-200D (polycarbonate polyol)
Product name: ETERNACOLL (registered trademark) PH-200D, manufactured by Ube Industries, Ltd., hydroxyl value 56 mg KOH/g (JIS K 1557)

<(C) Plasticizer>
(C-1) Ester group-containing plasticizer c1: Phthalate ester (DINP)
Product name: Sanso Cizer DINP, manufactured by New Japan Chemical Co., Ltd. (diisononyl phthalate), molecular weight: 419, number of ester groups: 2, ester mass (mass% of ester groups per molecule): 21%
(C-2) Hydrocarbon plasticizer c2: Polyolefin oil (LX004)
Product name: LUCANT (registered trademark) LX004, manufactured by Mitsui Chemicals, Inc. (ethylene-polypropylene copolymer), iodine value 0.1g/100g or less (JIS K 0070)

<(D) Inorganic Filler>
d1: Fused spherical silica (S-210)
Product name: S-210, manufactured by Nippon Steel Chemical & Material Co., Ltd. (fused spherical, non-crystalline silica), average particle size (d50): 26 μm, specific surface area: 1.8 m ² /g
d2: H-32
Product name: Hijilite (registered trademark) H-32, manufactured by Showa Denko K.K. (aluminum hydroxide), average particle size (d50): 8 μm, specific surface area: 2.0 m ² /g

<(G) Flame Retardant>
g1: Brominated flame retardant (Scitex 8010)
Product name: SAYTEX (registered trademark) 8010, manufactured by Almavel Japan Co., Ltd. (ethylene bis (pentabromophenyl))

<(H) Crosslinking Agent>
h1: OK all 100
Product name: OK All 100, manufactured by Okahata Sangyo Co., Ltd., molecular weight 212
h2: Octanediol Product name: Octanediol, manufactured by KH Neochem Co., Ltd. (2-ethyl-1,3-hexanediol), molecular weight 146.2
h3: 1,3BG
Product name: 1,3-butylene glycol, manufactured by KH Neochem Co., Ltd., molecular weight 90.1

Preparation of Polyurethane Resin Composition (1)
<Examples 1 to 13 and Comparative Examples 1 to 3>
Various polyurethane resin compositions were prepared using the components in the compositions and amounts (parts by mass) shown in Tables 1 to 3 according to the following procedure.

The (B) polyol compound, (C) plasticizer, and (D) inorganic filler shown in Tables 1 to 3 were mixed for 1 minute at 2000 rpm using a centrifugal mixer (Thinky Mixer, manufactured by Thinky Corporation).
The polyisocyanate compound (A) shown in Tables 1 to 3 was added to the above mixed components, and mixed for 1 minute at 2000 rpm using a planetary centrifugal mixer (Thinky Mixer, manufactured by Thinky Corporation). The resulting mixture was degassed to obtain the polyurethane resin compositions of Examples 1 to 13 and Comparative Examples 1 to 3.

<Viscosity>
The viscosity (23° C.) of each polyurethane resin composition obtained was measured using a B-type rotational viscometer. When the viscosity could not be measured at 23° C., the composition was heated to 40° C. and the viscosity was measured using a B-type rotational viscometer.

<Preparation of test pieces>
The prepared polyurethane resin composition was poured into a molding die of 1×1×80 mm or a molding die of 30 mm inner diameter and 10 mm height, and then heated at 80° C. for 16 hours and then allowed to stand at room temperature for 1 day to harden, to obtain test piece A (100×100×1 mm) and test piece B (diameter 30 mm and height 10 mm).

The hardness and volume resistivity of the obtained test piece A (1 x 1 x 80 mm) and test piece B (diameter 30 mm and height 10 mm) were measured using the test methods described below. The results are shown in Table 1.

<Hardness>
The hardness (Type A) of test piece B (diameter 30 mm, height 10 mm) at a temperature of 23° C. was measured in accordance with JIS K 6253 using a hardness meter (Asker Rubber Hardness Meter Type A, manufactured by Kobunshi Keiki Co., Ltd.).

<Dielectric constant and dielectric loss tangent>
The dielectric constant and dielectric loss tangent were measured by a cavity resonator perturbation method using test piece A (1×1×80 mm). An ENA network analyzer N5071C manufactured by Agilent Technologies was used as the measuring device. The measurement conditions were a frequency of 10 GHz and a measurement temperature of 23° C. For Example 12, the measurement was also performed at a frequency of 5 GHz and a measurement temperature of 23° C.

The dielectric loss was calculated from the obtained dielectric constant and dielectric tangent values according to the following formula.

Dk: relative dielectric constant Df: dielectric tangent f: frequency

Note that "-" in Table 2 indicates that data has not been obtained.

The relative dielectric constant of Example 12 at 5 GHz was 2.4, and the dielectric tangent was 0.002.

<Judgment Results>
As seen from Table 1, the polyurethane resin compositions of Examples 1 to 6 containing a polyolefin-based polyol as a polyol compound had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric dissipation factor of 0.01 or less. On the other hand, the polyurethane resin compositions of Comparative Examples 1 to 3 containing other polyols had a relative dielectric constant of 3.0 or less at 10 GHz, but a dielectric dissipation factor of more than 0.01.

From Table 2, the polyurethane resin compositions of Examples 7 to 19, which contain polyolefin-based polyol and ester group-containing polyol as polyol compounds and have an ester content of less than 9.5%, had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric loss tangent of 0.01 or less. The polyurethane resin composition of Example 10, which contains polyolefin-based polyol as polyol compound, ester group-containing plasticizer as plasticizer, and has an ester content of less than 9.5%, had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric loss tangent of 0.01 or less. Furthermore, the polyurethane resin composition of Example 11, which contains polyolefin-based polyol as polyol compound and olefin-based plasticizer as plasticizer, had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric loss tangent of 0.01 or less. In addition, the polyurethane resin composition of Example 12, which contains a polyolefin-based polyol as a polyol compound and an olefin-based plasticizer as a plasticizer, had a relative dielectric constant of 3.0 or less at 5 GHz and 10 GHz, and a dielectric loss tangent of 0.01 or less. The polyurethane resin compounds of Examples 10 to 12 had low viscosities of 7 to 15 Pa·s at 23° C. Thus, the polyurethane resin compounds of Examples 10 to 12 have the advantage of being easily moldable at room temperature.
On the other hand, the polyurethane resin composition of Comparative Example 1, which contained an ester group-containing polyol as the polyol compound and had an ester content of 9.9%, had a relative dielectric constant of 3.0 or less at 10 GHz, but a dielectric loss tangent of more than 0.01.

As shown in Table 3, the polyurethane resin composition of Example 13, which contains a polyolefin-based polyol as a polyol compound and further contains an inorganic filler, had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric loss tangent of 0.01 or less.

Preparation of polyurethane resin composition (2)
<Examples 14 to 25>
Various polyurethane resin compositions were prepared in the same manner as above using the components in the compositions and amounts (parts by mass) shown in Tables 4 and 5. The hardness, dielectric constant, and dielectric tangent were measured and the dielectric loss was calculated in the same manner as above.

<Judgment Results>
As shown in Table 4, the polyurethane resin compositions of Examples 14 to 19 containing an isocyanate compound, a polyolefin-based polyol as a polyol compound, and a crosslinking agent had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric tangent of 0.01 or less.

From Table 5, the polyurethane resin compositions of Examples 20 to 23, which contain an isocyanate compound, a polyolefin polyol as a polyol compound, an ester group-containing plasticizer as a plasticizer, and an inorganic filler or flame retardant, and have an ester content of less than 9.5%, had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric dissipation factor of 0.01 or less. In addition, the polyurethane resin compositions of Examples 24 to 25, which contain an isocyanate compound, a polyolefin polyol as a polyol compound, a hydrocarbon plasticizer as a plasticizer, and an inorganic filler or flame retardant, and have an ester content of less than 9.5%, had a relative dielectric constant of 3.0 or less at 10 GHz and a dielectric dissipation factor of 0.01 or less.

The cured polyurethane resin obtained from the polyurethane resin composition of the present invention has low dielectric loss in the high frequency band and excellent moldability, and therefore can be used for flexible substrates, adhesives for multilayer substrates, surface coating agents, sealants, coverlays, bonding sheets, copper foils, laminates, dry films, electronic component materials, etc.

Claims (14)

A polyurethane resin composition comprising (A) a polyisocyanate compound, (B) a polyol compound, and (C) a plasticizer, the polyurethane resin composition having a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.01 or less,
The (B) polyol compound includes a hydrogenated polybutadiene polyol , and
The (C) plasticizer is a cooligomer of ethylene and an α-olefin.
A polyurethane resin composition. 2. The polyurethane resin composition according to claim 1 , wherein the content of the plasticizer (C) is 0.01 to 50 mass% relative to 100 mass% of the polyurethane resin composition . The polyurethane resin composition according to claim 1 or 2 , wherein the polyisocyanate compound (A) is an aromatic polyisocyanate compound. The polyurethane resin composition according to claim 3 , wherein the aromatic polyisocyanate compound is a diphenylmethane diisocyanate compound. 4. The polyurethane resin composition according to claim 3 , wherein the aromatic polyisocyanate compound is 4,4'-diphenylmethane diisocyanate or a modified or polynuclear compound thereof. The polyol compound (B) further contains an ester group-containing polyol (B-2), and
The polyurethane resin composition according to any one of claims 1 to 5 , wherein the content of the ester contained in the polyurethane resin composition is less than 9.5%. The (C) plasticizer further contains an ester group-containing plasticizer, and
The ester content in the polyurethane resin composition is less than 9.5%.
The polyurethane resin composition according to any one of claims 1 to 6 . The polyurethane resin composition according to any one of claims 1 to 7 , further comprising (D) an inorganic filler. The polyurethane resin composition according to claim 8 , wherein the inorganic filler (D) is fused spherical silica or aluminum hydroxide. The polyurethane resin composition according to any one of claims 1 to 9 , further comprising (H) a crosslinking agent. The polyurethane resin composition according to any one of claims 1 to 10 , which does not contain polyphenylene ether. The polyurethane resin composition according to any one of claims 1 to 11 , which is used for sealing electric and electronic parts. A sealing material comprising the polyurethane resin composition according to any one of claims 1 to 12 . An electric/electronic component resin-sealed with the sealing material according to claim 13 .