JP7209886B1 - Vinyl group-containing prepolymer and curable resin composition - Google Patents

Abstract

Kind Code: A1 A vinyl group-containing prepolymer having excellent dielectric properties is provided. SOLUTION: A vinyl group-containing prepolymer according to an embodiment is derived from a first portion derived from a hydrogenated product of a conjugated diene polymer polyol and at least one polyisocyanate selected from an aliphatic polyisocyanate and an alicyclic polyisocyanate. and a third portion derived from a hydroxy group-containing aromatic vinyl compound. The first portion and the second portion are linked through urethane bonds formed by reaction of the hydroxy groups of the hydrogenated compound with the isocyanate groups of the polyisocyanate. The second portion and the third portion are bonded via a urethane bond formed by reaction between the isocyanate group of the polyisocyanate and the hydroxy group of the hydroxy group-containing aromatic vinyl compound. [Selection figure] None

Description

An embodiment of the present invention relates to a vinyl group-containing prepolymer, a curable resin composition containing the same, and a cured product thereof.

As a curable composition that can be cured by heat or the like, Patent Document 1 discloses a thermosetting composition comprising a vinyl group-containing prepolymer obtained by reacting an organic isocyanate compound and a hydroxy group-containing aromatic vinyl compound, and a vinyl monomer. A flexible resin composition is disclosed. As an example, in Patent Document 1, 1 mol of polybutadiene glycol and 2 mol of 1,3-phenylene diisocyanate are reacted, and further 2 mol of hydroxyethylstyrene is reacted to obtain a vinyl group at the end. A prepolymer having

Japanese Patent Publication No. 52-43514

However, it has been found that the vinyl group-containing prepolymer described in Patent Document 1 has insufficient dielectric properties when used, for example, in applications where high-frequency electrical signals are used.

An object of the present invention is to provide a vinyl group-containing prepolymer having excellent dielectric properties.

で表される化合物であり、式（１）中のＲ^１は炭素数１～４のアルカンジイル基を表し、Ｒ^２は炭素数１～４のアルキル基を表し、ｐは０～４の整数を表す、［１］～［３］のいずれか１項に記載のビニル基含有プレポリマー。
［５］ ［１］～［４］のいずれか１項に記載のビニル基含有プレポリマーを含む硬化性樹脂組成物。
［６］ 高周波絶縁材料用である、［５］に記載の硬化性樹脂組成物。
［７］ ［５］または［６］に記載の熱硬化性樹脂組成物が硬化した硬化物。 The present invention includes embodiments shown below.
[1] A first portion derived from a hydrogenated conjugated diene polymer polyol, a second portion derived from at least one of an aliphatic polyisocyanate and an alicyclic polyisocyanate, and a hydroxy group-containing aromatic vinyl a third portion derived from the compound;
The first portion and the second portion are bonded via a urethane bond formed by the reaction of the hydroxy group of the hydrogenated compound with the isocyanate group of the polyisocyanate, and the second portion and the third portion are connected to the polyisocyanate. A vinyl group-containing prepolymer having a structure in which an isocyanate group of an isocyanate and a hydroxyl group of the hydroxyl group-containing aromatic vinyl compound are reacted with each other via a urethane bond, and which has a terminal vinyl group.
[2] The vinyl group-containing prepolymer according to [1], wherein the hydrogenated conjugated diene polymer polyol has a number average molecular weight of 500 to 5,000.
[3] The vinyl group-containing prepolymer according to [1] or [2], wherein the hydrogenated conjugated diene polymer polyol is hydrogenated polybutadiene polyol and/or hydrogenated polyisoprene polyol.
[4] The hydroxy group-containing aromatic vinyl compound has the following general formula (1):

In formula (1), R ¹ represents an alkanediyl group having 1 to 4 carbon atoms, R ² represents an alkyl group having 1 to 4 carbon atoms, and p is an integer of 0 to 4. The vinyl group-containing prepolymer according to any one of [1] to [3].
[5] A curable resin composition containing the vinyl group-containing prepolymer according to any one of [1] to [4].
[6] The curable resin composition according to [5], which is used as a high-frequency insulating material.
[7] A cured product obtained by curing the thermosetting resin composition according to [5] or [6].

According to embodiments of the present invention, it is possible to provide a vinyl group-containing prepolymer having excellent dielectric properties.

The vinyl group-containing prepolymer according to this embodiment is a prepolymer having a vinyl group at its end. As used herein, the term "prepolymer" refers to a substance that is in a preliminary stage to become a polymer, and refers to a substance that exhibits curability such that it can be cured by causing a polymerization or cross-linking reaction with heat, light, or the like.

The vinyl group-containing prepolymer according to the present embodiment includes a first portion derived from a hydrogenated product (A) of a conjugated diene polymer polyol, and at least one of an aliphatic polyisocyanate and an alicyclic polyisocyanate (B ) and a third portion derived from the hydroxy group-containing aromatic vinyl compound (C). In the vinyl group-containing prepolymer, the first portion and the second portion are bonded via urethane bonds formed by reaction of the hydroxy groups of the hydrogenated product (A) and the isocyanate groups of the polyisocyanate (B), It has a structure in which the second portion and the third portion are bonded through a urethane bond formed by reaction between the isocyanate group of the polyisocyanate (B) and the hydroxy group of the hydroxy group-containing aromatic vinyl compound (C). Therefore, the vinyl group-containing prepolymer has a urethane bond together with the vinyl group.

In one embodiment, the vinyl group-containing prepolymer reacts a hydrogenated conjugated diene polymer polyol (A) with at least one of an aliphatic polyisocyanate and an alicyclic polyisocyanate (B). The isocyanate group of the isocyanate group-containing primary product (D) obtained by reacting the hydroxy group of the hydroxy group-containing aromatic vinyl compound (C). However, this description is not intended to limit the method for synthesizing the vinyl group-containing prepolymer. For example, after reacting the hydrogenated product (A) and the polyisocyanate (B), the resulting product may be reacted with the hydroxy group-containing aromatic vinyl compound (C). Alternatively, after reacting the polyisocyanate (B) with the hydroxy group-containing aromatic vinyl compound (C), the resulting product may be reacted with the hydrogenated product (A).

The hydrogenated conjugated diene polymer polyol (A) has a structure obtained by hydrogenating the conjugated diene polymer polyol. A conjugated diene-based polymer polyol has a structure in which a hydroxy group is introduced into a conjugated diene-based polymer obtained by polymerizing a conjugated diene-based monomer. Conjugated diene-based monomers include, for example, 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, etc. Any one or two or more of these may be used. . Preferred are 1,3-butadiene and/or isoprene. Therefore, the hydrogenated conjugated diene polymer polyol (A) is preferably hydrogenated polybutadiene polyol and/or hydrogenated polyisoprene polyol, more preferably hydrogenated polybutadiene polyol from the viewpoint of high elongation.

As the hydrogenated conjugated diene polymer polyol (A), one having an average of 1.5 or more hydroxy groups per molecule is preferably used, more preferably an average of 1.6 to 2.5. . More preferably, a hydrogenated conjugated diene polymer diol having an average of 1.8 to 2.1 hydroxy groups per molecule (eg, hydrogenated polybutadiene diol, hydrogenated polyisoprene diol) is used. . As used herein, the number of hydroxy groups (number of functional groups) per molecule is a value calculated by the following formula.
Number of functional groups = {(hydroxyl value) x (Mn)}/(56.1 x 1000)

In the hydrogenated conjugated diene polymer polyol (A), the microstructure of the conjugated diene polymer chain forming the basic skeleton is not particularly limited, and may be 1,4-bond type, 1,2-bond type, 3, A 4-bond type or a mixture of two or more thereof may be used. For example, hydrogenated polybutadiene polyol has a structure obtained by hydrogenating polybutadiene polyol having hydroxyl groups at both ends of a 1,4-bonded, 1,2-bonded, or mixed polybutadiene structure in the molecule. It can be anything you have. Further, the hydrogenated polyisoprene polyol is a polyisoprene structure having a 1,4-bonded, 1,2-bonded, 3,4-bonded, or mixed polyisoprene structure with hydroxyl groups at both ends. It may have a structure obtained by hydrogenating isoprene polyol. In one embodiment, the microstructure of the hydrogenated polybutadiene polyol may have a 1,2-linkage content of 50 mol % or more, or from 50 to 80 mol %. Here, the microstructure can be measured by ¹³ C-NMR.

The hydrogenated conjugated diene polymer polyol (A) is obtained by hydrogenating some or all of the unsaturated double bonds contained in the conjugated diene polymer polyol. Therefore, the above 1,4-bond type, 1,2-bond type and 3,4-bond type are used with the concept of including both hydrogenated and non-hydrogenated.

In the hydrogenated conjugated diene polymer polyol (A), the degree of hydrogenation is not particularly limited. For example, the iodine value may be 40 g/100 g or less, 30 g/100 g or less, or 25 g/100 g or less. , 15 g/100 g or less, or 10 g/100 g or less. As used herein, the iodine value is measured according to JIS K0070:1992.

The molecular weight of the hydrogenated conjugated diene polymer polyol (A) is not particularly limited, but the number average molecular weight (Mn) is preferably 500 to 5,000, more preferably 1,000 to 4,500, and still more preferably 1,500. ~4000.

As used herein, the number average molecular weight (Mn) is a value measured by a GPC method (gel permeation chromatography) and calculated using a standard polystyrene calibration curve. GPC conditions are, for example, column: "Shodex GPC columns KF-601, KF-602, KF-603, KF-604" manufactured by Showa Denko Co., Ltd. (4 columns connected), mobile phase: THF (tetrahydrofuran), mobile The phase flow rate is 0.6 mL/min, the column temperature is 40° C., the sample injection volume is 10 μL, and the sample concentration is 0.1 mass %.

The hydroxyl value of the hydrogenated conjugated diene polymer polyol (A) is not particularly limited, and may be, for example, 10 to 200 mgKOH/g, 15 to 120 mgKOH/g, 20 to 100 mgKOH/g, or 25 to 80 mgKOH. /g. As used herein, the hydroxyl value is measured according to JIS K1557-1:2007, Method A.

Aliphatic polyisocyanate and/or alicyclic polyisocyanate is used as the polyisocyanate (B).

Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 1 ,5-pentanediisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate and the like. These can be used either singly or in combination of two or more.

Examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), dicyclohexylmethane 4,4′-diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1, 3-bis(isocyanatomethyl)cyclohexane and the like. These can be used either singly or in combination of two or more.

As the polyisocyanate (B), it is preferable to use an alicyclic polyisocyanate, more preferably isophorone diisocyanate and/or dicyclohexylmethane 4,4'-diisocyanate, from the viewpoint of lowering the dielectric loss tangent. That is. Isophorone diisocyanate is more preferably used from the viewpoint of reaction control when synthesizing a vinyl group-containing prepolymer.

The hydroxy group-containing aromatic vinyl compound (C) is a vinyl compound having a hydroxy group and an aromatic ring, and one having one vinyl group and one hydroxy group is preferably used. As the hydroxy group-containing aromatic vinyl compound (C), it is preferable to use a compound represented by the following general formula (1).

In formula (1), R ¹ represents an alkanediyl group having 1 to 4 carbon atoms. Specific examples of R ¹ include a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group and an ethylethylene group. The bonding position of R ¹ OH to the benzene ring may be ortho, meta or para to the vinyl group.

In formula (1), R ² represents an alkyl group having 1 to 4 carbon atoms. Specific examples of R ² include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group and tert-butyl group. p in formula (1) is the number of substituents R ² on the benzene ring and represents an integer of 0-4, preferably an integer of 0-2. The bonding position of ^R2 to the benzene ring may be ortho, meta or para to the vinyl group.

Examples of the hydroxy group-containing aromatic vinyl compound (C) include 4-vinylbenzyl alcohol, 3-vinylbenzyl alcohol, 2-vinylbenzyl alcohol, p-(2-hydroxypropyl)styrene, p-hydroxyethylstyrene, o -Hydroxyethylstyrene and the like, and any one of them or a combination of two or more of them may be used. Vinylbenzyl alcohol is used as the hydroxy group-containing aromatic vinyl compound (C), that is, at least one selected from the group consisting of 4-vinylbenzyl alcohol, 3-vinylbenzyl alcohol, and 2-vinylbenzyl alcohol. of vinylbenzyl alcohol is preferably used.

The primary product (D) is a compound having an isocyanate group obtained by reacting a hydrogenated conjugated diene polymer polyol (A) with a polyisocyanate (B). For example, by reacting 2 mol of the polyisocyanate (B) with the hydrogenated product (A) in an amount corresponding to 1 mol, a primary product (D) having isocyanate groups at both ends can be obtained.

The reaction between the hydrogenated product (A) and the polyisocyanate (B) may be carried out without a solvent or in an organic solvent. The reaction temperature is not particularly limited, and may be, for example, 10 to 100°C or 20 to 80°C. As the organic solvent, for example, a diluent (vinyl monomer having no active hydrogen), which will be described later, may be used. In that case, a polymerization inhibitor may be added to inhibit their polymerization. Moreover, you may use a well-known urethanization catalyst in the case of reaction.

In one embodiment, the primary product (D) comprises a first portion derived from the hydrogenated product (A) and a second portion derived from the polyisocyanate (B), and via urethane bonds at both ends of the first portion It has a structure in which the second portion is bound at the end and has an isocyanate group at both ends. The urethane bond is formed by reaction between the hydroxy group of the hydrogenated product (A) and the isocyanate group of the polyisocyanate (B).

In one embodiment, the vinyl group-containing prepolymer is obtained by reacting the isocyanate group of the primary product (D) with the hydroxy group of the hydroxy group-containing aromatic vinyl compound (C). For example, by reacting hydroxy group-containing aromatic vinyl compound (C) in an amount corresponding to 2 mol with 1 mol of primary product (D), a vinyl group-containing prepolymer having vinyl groups at both ends can be obtained. be done.

The reaction between the primary product (D) and the hydroxy group-containing aromatic vinyl compound (C) may be carried out without solvent or in an organic solvent. The reaction temperature is not particularly limited, and may be, for example, 10 to 100°C or 20 to 80°C. As the organic solvent, for example, a diluent (vinyl monomer having no active hydrogen), which will be described later, may be used. Further, in the reaction, a known urethanization catalyst or a polymerization inhibitor that inhibits polymerization of vinyl groups may be added.

The vinyl group-containing prepolymer contains a third portion derived from the hydroxy group-containing aromatic vinyl compound (C) in addition to the first portion and the second portion, and the second portion and the third portion are bonded via a urethane bond. have a structured structure. In one embodiment, the urethane linkages are formed by reaction of the isocyanate groups of the primary product (D) with the hydroxy groups of the hydroxy group-containing aromatic vinyl compound (C). The vinyl group-containing prepolymer has vinyl groups derived from the hydroxy group-containing aromatic vinyl compound (C) at both ends.

式（２）中、Ｒ^１、Ｒ^２およびｐは、式（１）中のＲ^１、Ｒ^２およびｐと同じであり、両端のＲ^１、Ｒ^２およびｐはそれぞれ同一でも異なってもよい。 A vinyl group-containing prepolymer according to one embodiment is represented by the following general formula (2).

In formula (2), R ¹ , R ² and p are the same as R ¹ , R ² and p in formula (1), and R ¹ , R ² and p at both ends may be the same or different. .

In formula (2), X represents the first portion, i.e., the residue of the hydrogenated conjugated diene polymer polyol (A), specifically, the hydrogenated conjugated diene polymer polyol (A) represents the portion excluding the hydroxyl groups at both ends. Y represents the second portion, that is, the residue of the polyisocyanate (B), and more specifically represents the portion of the polyisocyanate (B) excluding the isocyanate groups at both terminals. Multiple Y's may be the same or different. Both ends of formula (2) are bound to the third portion. The third portion is the residue of the hydroxy group-containing aromatic vinyl compound (C), which is the portion of the hydroxy group-containing aromatic vinyl compound (C) from which the hydroxy group has been removed.

n in Formula (2) is an integer of 1 or more. n represents the number of repeating bonds between the first portion and the second portion, and molecules with different n may be mixed. Although n=1 is preferred, n=2 or more may be included. The upper limit of n is not particularly limited, and may be 20 or less, for example.

As described above, in the vinyl group-containing prepolymer of formula (2), the second portion is bonded to both ends of the first portion via urethane bonds, and the third portion is bonded to the second portions at both ends via urethane bonds. It is a urethane bond-containing vinyl compound having a bonded structure, and the first portion and the second portion may be alternately bonded multiple times, or may be a mixture of different repeating numbers.

The number average molecular weight (Mn) of the vinyl group-containing prepolymer is not particularly limited, and may be, for example, 1,000 to 50,000 or 2,000 to 20,000.

Since the vinyl group-containing prepolymer has a vinyl group, it exhibits curability such that it can be cured by addition polymerization with heat, light, or the like. Therefore, the curable resin composition according to the embodiment contains the vinyl group-containing prepolymer. In one embodiment, the curable resin composition is preferably a thermosetting resin composition that is cured by heat.

The curable resin composition may contain, together with the vinyl group-containing prepolymer, a vinyl monomer copolymerizable therewith. As the vinyl monomer, a monofunctional (i.e., having one vinyl group) vinyl monomer may be used as a diluent, or a bifunctional or higher (i.e., having a plurality of vinyl groups) may be used as a cross-linking agent. Vinyl monomers may also be used.

Examples of monofunctional vinyl monomers include styrene, chlorostyrene, butylstyrene, acrylic acid, methacrylic acid, ethyl acrylate, methyl methacrylate, acrylonitrile, vinylpyrrolidone, and vinyl acetate. Divinylbenzene, 1,5-hexadiene and the like are examples of the bifunctional or higher vinyl monomer.

The curable resin composition further includes fillers such as inorganic fillers, thermoplastic resins, flame retardants, curing accelerators, polymerization initiators, antifoaming agents, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes and pigments, etc. may contain various ingredients such as colorants, lubricants and dispersants.

Moreover, the curable resin composition may contain an organic solvent in order to adjust its viscosity, and the curable resin composition may be a solution containing the vinyl group-containing prepolymer. As the organic solvent, those capable of dissolving the vinyl group-containing prepolymer are used. Amides such as dimethylformamide, aromatic hydrocarbons such as toluene and xylene, and the like can be mentioned, and these can be used singly or in combination of two or more.

Examples of polymerization initiators include di-tert-butyl peroxide, tert-butyl hydroperoxide, organic peroxides such as benzoyl peroxide, radical initiators such as azo compounds such as azobisisobutyronitrile, benzophenone, and acetophenone. and photoinitiators such as The amount of the polymerization initiator is not particularly limited, and may be, for example, 0.01 to 10 parts by mass with respect to 100 parts by mass of the vinyl group-containing prepolymer.

The vinyl group-containing prepolymer has a low dielectric loss tangent and a low dielectric constant with respect to high-frequency electrical signals, that is, excellent dielectric properties when used in applications where high-frequency electrical signals are used. Therefore, the curable resin composition containing the vinyl group-containing prepolymer is suitable for insulating applications against high-frequency electrical signals, that is, for high-frequency insulating materials. Here, high frequency means 1 GHz or higher, more preferably 3 to 80 GHz.

The high-frequency insulating material is not particularly limited, but includes, for example, a material for forming a printed circuit board (high-frequency printed circuit board) used for transmitting high-frequency signals, and a material forming one layer (insulating layer) of the high-frequency printed circuit board. is mentioned.

The present invention will be described in more detail below based on Examples and Comparative Examples, but the present invention is not limited thereto.

The details of the conjugated diene polymer polyols used in the examples are as follows.

- Hydrogenated polybutadiene diol (1): "Krasol HLBH-P3000" manufactured by CRAY VALLEY, number average molecular weight: 3000, 1,2-bond type content: 65 mol%, number of functional groups: 1.9, hydroxyl value: 36 mg KOH / g, iodine value: 7 g / 100 g

- Hydrogenated polybutadiene diol (2): "Krasol HLBH-P2000" manufactured by CRAY VALLEY, number average molecular weight: 2000, 1,2-bond type content: 65 mol%, number of functional groups: 1.9, hydroxyl value: 53 mg KOH /g, iodine value: 8g/100g

- Hydrogenated polybutadiene diol (3): "NISSO-PB GI-3000" manufactured by Nippon Soda Co., Ltd., number average molecular weight: 3100, number of functional groups: 2.0, hydroxyl value: 36 KOHmg/g, iodine value: 5 g/100 g

- Hydrogenated polyisoprene diol (4): "EPOL" manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight: 2500, 1,2-bond content: 20 mol%, number of functional groups: 2.0, hydroxyl value: 45 mg KOH / g, iodine value: 7 g / 100 g

- Polybutadiene diol (5): "Polybd R45HT" manufactured by Idemitsu Kosan Co., Ltd. (number average molecular weight: 2800, number of functional groups: 2.0, hydroxyl value: 40 KOHmg/g)

[Example 1]
300 g (0.1 mol) of hydrogenated polybutadiene diol (1), 44.4 g (0.2 mol) of isophorone diisocyanate (IPDI), and dioctyl lily of the valley were added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 0.04 g of the rate was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol (VBA) was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1 mass % or less. Thus, a vinyl group-containing prepolymer of Example 1 was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 4,500 measured by the GPC method.

[Example 2]
200 g (0.1 mol) of hydrogenated polybutadiene diol (2), 44.4 g (0.2 mol) of isophorone diisocyanate, and 0.2 mol of dioctyltin laurate were added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 03 g was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 3,500 as measured by the GPC method.

[Example 3]
310 g (0.1 mol) of hydrogenated polybutadiene diol (3), 44.4 g (0.2 mol) of isophorone diisocyanate, and 0.2 mol of dioctyltin laurate were added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 04 g was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 4,600 measured by the GPC method.

[Example 4]
250 g (0.1 mol) of hydrogenated polyisoprene diol (4), 44.4 g (0.2 mol) of isophorone diisocyanate, and dioctyl are added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer and nitrogen sparge. 0.03 g of stannous laurate was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 3,800 measured by the GPC method.

[Example 5]
300 g (0.1 mol) of hydrogenated polybutadiene diol (1), 33.6 g (0.2 mol) of hexamethylene diisocyanate (HDI), and dioctyltin were added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 0.04 g of laurate was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 5,500 as measured by the GPC method.

[Example 6]
300 g (0.1 mol) of hydrogenated polybutadiene diol (1) and 52.47 g (0.1 mol) of hydrogenated polybutadiene diol (1) and 52.47 g (0.1 mol) of dicyclohexylmethane 4,4'-diisocyanate (hydrogenated MDI) were placed in a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 2 mol) and 0.04 g of dioctyltin laurate were charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 5,500 measured by the GPC method.

[Example 7]
300 g (0.1 mol) of hydrogenated polybutadiene diol (1), 30.8 g (0.2 mol) of 1,5-pentanediisocyanate, and dioctyltin were added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 0.04 g of laurate was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 5,500 as measured by the GPC method.

[Comparative Example 1]
A four-necked flask equipped with a stirrer, reflux condenser, thermometer and dropping device was charged with 280 g (0.1 mol) of polybutadiene diol (5), 280 g of toluene, and 20.2 g (0.2 mol) of triethylamine. 19.91 g (0.22 mol) of acid chloride was added dropwise over 1 hour. After completion of dropping, reaction was carried out at room temperature for 1 hour. 50 g of isopropyl alcohol and 150 g of ion-exchanged water were added to the reaction solution, stirred and allowed to stand, and the separated aqueous layer was removed. The prepolymer of Comparative Example 1 was then obtained by removing the solvent under reduced pressure. The resulting prepolymer had a number average molecular weight Mn of 3,200 as measured by the GPC method.

[Comparative Example 2]
A four-necked flask equipped with a stirrer, reflux condenser and thermometer was charged with 280 g (0.1 mol) of polybutadiene diol (5), 44.4 g (0.2 mol) of isophorone diisocyanate, and 0.04 g of dioctyltin laurate. It was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 4,200 measured by the GPC method.

[Comparative Example 3]
300 g (0.1 mol) of hydrogenated polybutadiene diol (1), 34.84 g (0.2 mol) of tolylene diisocyanate (TDI), and dioctyltin were added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 0.04 g of laurate was charged and reacted at 50 to 80° C. for 3 hours. Next, 29.52 g (0.22 mol) of 4-vinylbenzyl alcohol was added, and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. A containing prepolymer was obtained. The obtained vinyl group-containing prepolymer had a number average molecular weight Mn of 5,000 as measured by the GPC method.

[Comparative Example 4]
300 g (0.1 mol) of hydrogenated polybutadiene diol (1), 44.4 g (0.2 mol) of isophorone diisocyanate, and 0.2 mol of dioctyltin laurate were added to a four-necked flask equipped with a stirrer, reflux condenser and thermometer. 04 g was charged and reacted at 50 to 80° C. for 3 hours. Next, 25.52 g (0.22 mol) of 2-hydroxyethyl acrylate was added and further reacted at 50 to 80° C. until the amount of free isocyanate was 0.1% by mass or less. got The prepolymer obtained had a number average molecular weight Mn of 4,500 as measured by the GPC method.

Dielectric properties (dielectric constant Dk, dielectric loss tangent Df) and cured film physical properties (glass transition temperature Tg, strength, elongation) of the prepolymers of Examples 1 to 7 and Comparative Examples 1 to 4 obtained above were measured. bottom. Each measurement method is as follows.

[Preparation of cured product]
0.05 g of a thermal polymerization initiator (“PERBUTYL P” manufactured by NOF Corporation) was added to 10 g of each of the above prepolymers and dissolved. Using a test single-acting compression molding machine (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), 1.5 g of the sample was pressed at a pressure of 10 Pa and a temperature of 200° C. for 5 minutes to prepare a flat plate of 40 mm×40 mm×1 mm thickness.

[Permittivity, dissipation factor]
A test piece having a width of 2 mm, a thickness of 1 mm, and a length of 40 mm was prepared by cutting the flat plate obtained above. The dielectric constant Dk and the dielectric loss tangent Df at 10 GHz of the test piece were measured using a cavity resonator method dielectric constant measuring device (manufactured by KEYSIGHT).

[Glass transition temperature Tg]
A dynamic viscoelasticity measuring device (manufactured by UBM Co., Ltd., model number: Rheogel-E4000) was used to measure the glass transition temperature. A test piece having a width of 2 mm, a thickness of 1 mm, and a length of 40 mm was prepared by cutting the flat plate obtained above. The maximum value of the loss tangent (tan δ) measured under the conditions of a tensile sine wave, a frequency of 1 Hz, and a temperature increase rate of 3° C./min was obtained as the glass transition temperature.

[Strength, elongation]
A universal material testing machine (manufactured by A&D Co., Ltd., model number: RTC-1225A) was used to measure the strength and elongation. A test piece having a width of 5 mm, a thickness of 1 mm, and a length of 40 mm was prepared by cutting the flat plate obtained above. The test piece was subjected to a tensile test at a rate of 50 mm/min in accordance with JIS C2151:2019 to determine tensile strength (stress at break) and elongation at break.

The results are shown in Tables 1 and 2. In the prepolymer of Comparative Example 1, both ends of non-hydrogenated polybutadiene diol are reacted with acrylic acid chloride. In Comparative Example 1, the dielectric loss tangent was high and the dielectric properties were poor. In addition, the strength and elongation were low, and the physical properties of the cured film were poor. Furthermore, the glass transition temperature Tg was low and the heat resistance was poor.

In the vinyl group-containing prepolymer of Comparative Example 2, both ends of non-hydrogenated polybutadiene diol are reacted with a hydroxy group-containing aromatic vinyl compound via an alicyclic polyisocyanate. In Comparative Example 2, the dielectric loss tangent was high and the dielectric properties were poor. Further, the strength was low and the glass transition temperature Tg was low.

In the vinyl group-containing prepolymer of Comparative Example 3, both ends of hydrogenated polybutadiene diol are reacted with a hydroxy group-containing aromatic vinyl compound via an aromatic polyisocyanate. In Comparative Example 3, the dielectric constant and dielectric loss tangent were high, and the dielectric properties were poor. In addition, the elongation was low and the physical properties of the cured film were poor.

In the prepolymer of Comparative Example 4, both ends of hydrogenated polybutadiene diol are reacted with hydroxy-containing acrylate through aliphatic polyisocyanate. In Comparative Example 4, the dielectric constant and dielectric loss tangent were high, and the dielectric properties were poor.

On the other hand, in the vinyl group-containing prepolymers of Examples 1 to 7, hydroxy group-containing aromatic vinyl reacting compounds. In Examples 1 to 7, the dielectric constant and dielectric loss tangent were low, and the dielectric properties were excellent. In addition, the glass transition temperature Tg was higher than that of Comparative Example 1, the strength and elongation were higher, and the physical properties of the cured film were excellent.

It should be noted that the various numerical ranges described in the specification can be arbitrarily combined with their upper and lower limits, and all combinations thereof are described in this specification as preferred numerical ranges. Further, the description of the numerical range "X to Y" means X or more and Y or less.

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments, their omissions, replacements, modifications, etc., are included in the invention described in the scope of claims and equivalents thereof, as well as being included in the scope and gist of the invention.

Claims (6)

A first portion derived from a hydrogenated conjugated diene polymer polyol, a second portion derived from at least one of an aliphatic polyisocyanate and an alicyclic polyisocyanate, and a hydroxyl group-containing aromatic vinyl compound. and a third part to
The hydroxy group-containing aromatic vinyl compound has the following general formula (1):

In formula (1), R ¹ represents an alkanediyl group having 1 to 4 carbon atoms, R ² represents an alkyl group having 1 to 4 carbon atoms, and p is an integer of 0 to 4. represents
The first portion and the second portion are bonded via a urethane bond formed by the reaction of the hydroxy group of the hydrogenated compound with the isocyanate group of the polyisocyanate, and the second portion and the third portion are connected to the polyisocyanate. A vinyl group-containing prepolymer having a structure in which an isocyanate group of an isocyanate and a hydroxyl group of the hydroxyl group-containing aromatic vinyl compound are reacted with each other via a urethane bond, and which has a terminal vinyl group. 2. The vinyl group-containing prepolymer according to claim 1, wherein the hydrogenated conjugated diene polymer polyol has a number average molecular weight of 500 to 5,000. 2. The vinyl group-containing prepolymer according to claim 1, wherein the hydrogenated conjugated diene polymer polyol is hydrogenated polybutadiene polyol and/or hydrogenated polyisoprene polyol. A curable resin composition comprising the vinyl group-containing prepolymer according to any one of claims 1 to 3 . 5. The curable resin composition according to claim 4 , which is used as a high frequency insulating material. A cured product obtained by curing the curable resin composition according to claim 4 .