Polycarbodiimide compound, resin composition, and cured resin product

Abstract

The present invention provides a polycarbodiimide compound having a polyphenylene ether-based structure, capable of producing a cured resin product with a low dielectric constant and a low dielectric loss tangent, excellent low dielectric properties, and excellent adhesion to metal foil, as well as a resin composition containing the compound and a cured product thereof. The polycarbodiimide compound has a structure derived from polycarbodiimide obtained by diisocyanate polymerization (a) and a structure derived from polyphenylene ether (b), wherein the mass ratio of the structure derived from polyphenylene ether (b) to the structure derived from polycarbodiimide (a) (b / a) is 0.20 to 1.50.

Description

Polycarbodiimide compound, resin composition, and cured resin

[0001] The present invention relates to a polycarbodiimide compound having a structure based on polyphenylene ether, a resin composition containing the same, and a cured product thereof.

[0002] In electronic circuit boards used in various electronic devices, insulating materials forming insulating layers are required to have low dielectric constants and dielectric dissipation factors in order to reduce dielectric loss. Polyphenylene ether (PPE), known as an engineering plastic, has low dielectric constants and dielectric dissipation factors and is excellent in low dielectric properties, and is therefore also used as a resin material for such insulating materials.

[0003] PPE is used by being given various functional groups or modified to improve specific properties. For example, Patent Document 1 discloses functionalizing modified PPE having carboxy groups with carbodiimide to improve resistance to non-polar solvents and compatibility in blends with polymers.

[0004] Furthermore, Patent Document 2 discloses the use of a compound obtained by reacting a cyclic monocarbodiimide with a PPE having a carboxy group in order to obtain a cured resin product having excellent adhesion to a metal foil.

[0005] JP 63-315 A International Publication No. 2024 / 043083

[0006] However, Patent Document 1 does not mention the adhesion between PPE and metal foil. Furthermore, the carbodiimide-functionalized PPE in Patent Document 1 has a low carbodiimide group content, and therefore a cured resin product having sufficient adhesion to metal foil cannot be obtained. The compound produced by the reaction of PPE with a cyclic monocarbodiimide, as described in Patent Document 2, also has a low carbodiimide group content relative to the PPE, and therefore a cured resin product using this compound cannot be said to have sufficient adhesion to metal foil.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a polycarbodiimide compound having a PPE-based structure, which can give a cured resin product having a low dielectric constant and dielectric dissipation factor, excellent low dielectric properties, and excellent adhesion to metal foil, a resin composition containing the compound, and a cured resin thereof.

[0008] The present invention is based on the discovery that the use of a polycarbodiimide compound having a specific polycarbodiimide-based structure and a PPE-based structure improves the adhesion of a cured resin to a metal foil.

[0009] The present invention provides the following means: [1] A polycarbodiimide compound having a structure based on polycarbodiimide (a) formed by polymerization of diisocyanate and a structure based on polyphenylene ether (b), wherein the mass ratio (b / a) of the structure based on polyphenylene ether (b) to the structure based on polycarbodiimide (a) is 0.20 to 1.50. [2] The polycarbodiimide compound of [1], wherein the polycarbodiimide (a) has an average degree of polymerization of carbodiimide groups of 2.0 to 15.0. [3] The polycarbodiimide compound of [1] or [2], wherein the diisocyanate is at least one selected from the group consisting of alicyclic diisocyanates and aromatic diisocyanates. [4] The polycarbodiimide compound according to [3], wherein the alicyclic diisocyanate is at least one selected from the group consisting of dicyclohexylmethane-4,4'-diisocyanate and isophorone diisocyanate, and the aromatic diisocyanate is at least one selected from the group consisting of o-tolidine diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and tolylene-2,4-diisocyanate. [5] The polycarbodiimide compound according to any of [1] to [4], wherein the polyphenylene ether (b) has a number average molecular weight of 1,500 to 3,000. [6] The polycarbodiimide compound according to any of [1] to [5], wherein a structure based on the polycarbodiimide (a) and a structure based on the polyphenylene ether (b) are bonded via a urethane bond. [7] In the infrared absorption spectrum, 2100 to 2200 cm derived from the carbodiimide group －１ and the peak intensity (Ia) of 1150 to 1200 cm derived from the ether group of the polyphenylene ether (b). －１The polycarbodiimide compound according to any one of [1] to [6], wherein the ratio (Ia / Ib) of the peak intensity (Ib) of the polycarbodiimide (a) to the peak intensity (Ib) of the polycarbodiimide (a) is 0.70 to 4.00. [8] The polycarbodiimide compound according to any one of [1] to [7], wherein the polycarbodiimide (a) is a reaction product of the polycarbodiimide (a), the polyphenylene ether (b), and the compound having an unsaturated double bond (c), and the compound having an unsaturated double bond (c) has a functional group reactive with an isocyanate group. [9] The polycarbodiimide compound according to [8], wherein the amount of the polycarbodiimide (a) is 35 to 80 parts by mass per 100 parts by mass of the total of the polycarbodiimide (a), the polyphenylene ether (b), and the compound having an unsaturated double bond (c).

[10] The polycarbodiimide compound according to [8] or [9], wherein the functional group capable of reacting with an isocyanate group of the compound (c) having an unsaturated double bond is at least one selected from the group consisting of a hydroxyl group, an amino group, an isocyanate group, and a carboxy group.

[0010]

[11] The polycarbodiimide compound according to any one of [8] to

[10] , wherein the compound (c) having an unsaturated double bond is a hydroxyalkyl (meth)acrylate.

[12] A resin composition comprising the polycarbodiimide compound according to any one of [1] to

[11] and a compound (A) having an unsaturated double bond.

[13] The resin composition according to

[12] , further comprising a radical polymerization initiator (B).

[14] A cured resin product which is a cured product of the resin composition according to

[12] or

[13] .

[15] An insulating material for electronic circuit boards which is the resin composition according to

[12] or

[13] .

[0011] According to the present invention, there are provided a polycarbodiimide compound that can give a cured resin product having a low dielectric constant and dielectric loss tangent, excellent low dielectric properties, and excellent adhesion to metal foil, as well as a resin composition using the same and a cured product thereof.

[0012] The definitions and meanings of terms and notations used in this specification are as follows. A numerical range expressed using "to" means that the numerical values ​​before and after "to" are the lower and upper limits. For numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages may be combined independently. The lower and upper limits of a numerical range may be replaced with numerical values ​​described in the examples. The peak intensity in an infrared absorption (IR) spectrum refers to the peak height (baseline corrected) of absorbance in a specified wavenumber range in a Fourier transform infrared absorption (FTIR) spectrum. "(Meth)acrylic" is a general term for acrylic and methacrylic. Similarly, "(meth)acrylate" is a general term for acrylate and methacrylate.

[0013] [Polycarbodiimide Compound] The polycarbodiimide compound of the present invention (hereinafter also referred to as polycarbodiimide compound (X)) has a structure based on polycarbodiimide (a) obtained by polymerization of diisocyanate, and a structure based on polyphenylene ether (PPE) (b), and the mass ratio (b / a) of the structure based on PPE (b) to the structure based on polycarbodiimide (a) is 0.20 to 1.50. By using the polycarbodiimide compound (X) having such a PPE-based structure, a resin cured product can be obtained that has a low dielectric constant and dielectric loss tangent, an excellent low dielectric constant, and excellent adhesion to metal foil.

[0014] (Polycarbodiimide (a)) The polycarbodiimide compound (X) has a structure based on polycarbodiimide (a) formed by polymerization of diisocyanate. Polycarbodiimide (a) is a compound formed by polymerization of diisocyanate, having two or more carbodiimide groups per molecule and having isocyanate groups at both ends. From the viewpoint of obtaining a resin cured product having sufficient adhesion to metal foil, the average degree of polymerization of the carbodiimide groups is preferably 2.0 to 15.0, more preferably 2.0 to 13.0, and even more preferably 2.5 to 10.0. Here, the average degree of polymerization of the carbodiimide groups refers to the average number of carbodiimide groups formed by the decarboxylation condensation reaction of diisocyanate contained in one molecule. The average degree of polymerization of the carbodiimide groups can be determined by the method described in the Examples below.

[0015] Examples of diisocyanates that are constituent raw materials of polycarbodiimide (a) include aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates. These diisocyanates may be used alone or in combination of two or more. Among these, from the viewpoint of ease of production of polycarbodiimide (X), at least one selected from the group consisting of alicyclic diisocyanates and aromatic diisocyanates is preferred. From the viewpoint of ease of production of polycarbodiimide (a), alicyclic diisocyanates are more preferred.

[0016] Examples of aliphatic diisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, etc., and aliphatic diisocyanates containing an aromatic ring such as m-xylylene diisocyanate, tetramethylxylylene diisocyanate, etc. Examples of alicyclic diisocyanates include 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 2,2-bis(4-isocyanatocyclohexyl)propane, dicyclohexylmethane-4,4'-diisocyanate (HMDI), isophorone diisocyanate (IPDI), etc., of which HMDI and IPDI are preferred, and HMDI is more preferred. Examples of aromatic diisocyanates include o-tolidine diisocyanate (TODI), tolylene-2,4-diisocyanate (TDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), and 2,4,6-triisopropylbenzene-1,3-diyl diisocyanate, with TODI, TDI, 2,4'-MDI, and 4,4'-MDI being preferred.

[0017] The polycarbodiimide (a) may be prepared as a raw material for producing the polycarbodiimide compound (X), or the polycarbodiimide compound (X) having a structure based on the polycarbodiimide (a) may be produced by one-pot synthesis of a raw material mixture containing diisocyanate, which is a raw material for the polycarbodiimide (a), and PPE (b), without isolating the polycarbodiimide (a).

[0018] When a prepared polycarbodiimide (a) is used, the polycarbodiimide (a) can be produced by subjecting a diisocyanate to a carbodiimidation reaction in the presence of a catalyst. Examples of the carbodiimidation reaction include a decarboxylation condensation reaction of a diisocyanate in the presence of a carbodiimidation catalyst. When a polycarbodiimide compound (X) having a structure based on the polycarbodiimide (a) is produced by one-pot synthesis from a raw material mixture containing a diisocyanate, the carbodiimidation reaction is preferably carried out in the presence of a carbodiimidation catalyst.

[0019] Examples of carbodiimidization catalysts include phospholene oxides such as 1-phenyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, and 3-phospholene isomers thereof. Of these, 3-methyl-1-phenyl-2-phospholene-1-oxide is preferred from the standpoints of reactivity and availability. The amount of carbodiimidization catalyst used in the decarboxylation condensation reaction of diisocyanate is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.1 to 2 parts by mass, per 100 parts by mass of diisocyanate.

[0020] The decarboxylation condensation reaction of diisocyanate can be carried out in a solvent or without a solvent. Examples of the solvent that can be used include alicyclic ethers such as tetrahydrofuran, 1,3-dioxane, and dioxolane; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, percrene, trichloroethane, and dichloroethane; and cyclohexanone. The solvent may be used alone or in combination of two or more.

[0021] The reaction temperature for the decarboxylation condensation reaction is set appropriately depending on factors such as appropriate reaction acceleration and the degree of polymerization of the carbodiimide group, but is preferably 40 to 250°C, more preferably 50 to 230°C, and even more preferably 70 to 200°C. When the reaction is carried out in a solvent, the reaction temperature is preferably within the range of 40°C to the boiling point of the solvent. When an aromatic diisocyanate is used as the diisocyanate, the reaction temperature is preferably 40 to 100°C from the viewpoint of preventing the formation of an adduct with the carbodiimide group. When an alicyclic diisocyanate is used as the diisocyanate, the reaction temperature is preferably 150 to 200°C from the viewpoint of the reaction rate.

[0022] The reaction time for the decarboxylation condensation reaction is appropriately set depending on the reaction temperature, the degree of polymerization of the carbodiimide group, etc., but is preferably 0.5 to 100 hours, more preferably 1 to 70 hours, and even more preferably 2 to 30 hours. The decarboxylation condensation reaction is preferably carried out in an inert gas atmosphere such as nitrogen gas or a rare gas.

[0023] (PPE (b)) The polycarbodiimide compound (X) has a structure based on the polycarbodiimide (a) as well as a structure based on the PPE (b). The PPE (b) has a phenylene ether unit as a repeating structural unit, and the phenylene group in the phenylene ether unit may or may not have a substituent. The PPE (b) may also contain structural units other than the phenylene ether unit, as long as the effects of the present invention are not impaired.

[0024] The PPE (b) preferably has a repeating structural unit represented by the following formula (1).

[0025]

[0026] In formula (1), R １ ~R ４are each independently a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom, or a bromine atom), an alkyl group which may have a substituent (for example, a linear or branched alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, or a tert-butyl group, or a cyclic alkyl group having 6 to 10 carbon atoms such as a cyclohexyl group), an alkoxy group which may have a substituent (for example, an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, or a butoxy group), an aryl group which may have a substituent (for example, a phenyl group or a naphthyl group), an amino group which may have a substituent, a nitro group, or a carboxy group.

[0027] Specific examples of PPE include poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenylene ether), copolymers of 2,6-dimethylphenol and other phenols (for example, 2,3,6-trimethylphenol, 2-methyl-6-butylphenol, etc.), and polyphenylene ether copolymers obtained by coupling 2,6-dimethylphenol with biphenols or bisphenols.

[0028] The number average molecular weight of PPE (b) is preferably 1500 to 3000, more preferably 1800 to 2800, and even more preferably 2000 to 2500, from the viewpoints of the fluidity and ease of handling of polycarbodiimide compound (X). The number average molecular weight of PPE is a polystyrene-equivalent molecular weight determined by gel permeation chromatography (GPC) based on a calibration curve prepared using standard polystyrene samples. Specifically, it is determined by the method described in the Examples.

[0029] From the viewpoint of imparting good adhesion to metal foil to a cured resin product using the polycarbodiimide compound (X), it is preferred that the structure based on the polycarbodiimide (a) in the polycarbodiimide compound (X) and the structure based on the PPE (b) are bonded via a urethane bond. That is, it is preferred that the polycarbodiimide compound (X) has a urethane bond formed by reaction between an isocyanate group of the polycarbodiimide (a) and a hydroxyl group of the PPE (b).

[0030] To obtain a polycarbodiimide compound (X) having such a urethane bond, PPE (b) preferably has a hydroxyl group, more preferably has a hydroxyl group at the molecular chain terminal, and even more preferably has two or more hydroxyl groups per molecule. When PPE (b) is a linear molecule, it preferably has hydroxyl groups at both molecular chain terminals. The hydroxyl group equivalent of PPE (b) having a hydroxyl group is preferably 500 to 1200 g / mol, more preferably 600 to 1000 g / mol, and even more preferably 700 to 900 g / mol, from the viewpoint of imparting good adhesion to metal foil to a cured resin product using polycarbodiimide compound (X) by providing an appropriate concentration of urethane bonds in polycarbodiimide compound (X).

[0031] The urethane bond between the isocyanate group of the polycarbodiimide (a) and the hydroxyl group of the PPE (b) can be formed by a known method by a reaction using a urethane catalyst, if necessary. Examples of the urethane catalyst include amine catalysts such as triethylamine and triethylenediamine; and organometallic catalysts such as dibutyltin dilaurate and tetraoctyl titanate. The urethane catalyst may be used alone or in combination of two or more.

[0032] The content of PPE (b) in the raw material composition of polycarbodiimide compound (X) is preferably 0.1 to 1.5 mol, more preferably 0.2 to 1.0 mol, and even more preferably 0.3 to 0.8 mol per mol of polycarbodiimide (a), from the viewpoints of maintaining good low dielectric properties of a cured product of a resin composition using polycarbodiimide compound (X) and imparting good adhesion to a metal foil.

[0033] (Compound (c) Having an Unsaturated Double Bond) The polycarbodiimide compound (X) has a structure based on polycarbodiimide (a) and a structure based on polyphenylene ether (b), and is preferably a reaction product of polycarbodiimide (a), polyphenylene ether (b), and compound (c) having an unsaturated double bond. The compound (c) having an unsaturated double bond is a compound having a functional group capable of reacting with an isocyanate group. By including compound (c) having an unsaturated double bond in the raw material composition of polycarbodiimide compound (X), a polycarbodiimide compound (X) having an ethylenically unsaturated bond can be obtained. By using such a polycarbodiimide compound (X), it becomes easier to obtain a radically polymerizable resin composition that has good adhesion to metal foil.

[0034] Examples of functional groups that can react with an isocyanate group include a hydroxyl group, an amino group, an isocyanate group, and a carboxy group. These functional groups may be of one type alone or two or more types. By reacting with an isocyanate group, a urethane bond is formed in the case of a hydroxyl group, a urea bond in the case of an amino group, a carbodiimide bond in the case of an isocyanate group, and an amide bond in the case of a carboxy group.

[0035] Examples of the compound (c) having an unsaturated double bond include (meth)acrylate and vinyl compounds. The compound (c) having an unsaturated double bond may be used alone or in combination of two or more. Among these, (meth)acrylate is preferred from the viewpoint of easily obtaining a resin composition having good reactivity and adhesion to the metal foil, and hydroxy(meth)acrylate is more preferred from the viewpoint of ease of handling, and hydroxyalkyl(meth)acrylate is even more preferred.

[0036] The number of carbon atoms in the alkyl group of the hydroxyalkyl (meth)acrylate is preferably 1 to 15, more preferably 2 to 12, and even more preferably 2 to 10, and the alkyl group is preferably linear. Specific examples of hydroxyalkyl (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate. Of these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred.

[0037] When the raw material composition of the polycarbodiimide compound (X) contains a compound (c) having an unsaturated double bond, the content thereof is preferably 0.1 to 2.0 moles, more preferably 0.5 to 1.5 moles, and even more preferably 0.8 to 1.2 moles per mole of polycarbodiimide (a) from the viewpoint of maintaining good low dielectric properties of the cured product of the resin composition using the polycarbodiimide compound (X) and imparting good adhesion to metal foil. In this case, the content of the compound (c) having an unsaturated double bond in a total of 100 parts by mass of the polycarbodiimide (a), PPE (b), and compound (c) having an unsaturated double bond is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and even more preferably 3 to 20 parts by mass. Furthermore, the content of polycarbodiimide (a) is preferably 35 to 80 parts by mass, more preferably 40 to 80 parts by mass, and even more preferably 43 to 75 parts by mass, per 100 parts by mass of the total of polycarbodiimide (a), PPE (b), and compound (c) having an unsaturated double bond. Per 100 parts by mass, the content of PPE (b) is preferably 10 to 50 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 18 to 47 parts by mass.

[0038] The polycarbodiimide compound (X) exhibits a peak at 2100 to 2200 cm derived from the carbodiimide group in the infrared absorption (IR) spectrum. －１ and the peak intensity of 1150 to 1200 cm due to the ether group of PPE (b). －１The ratio (Ia / Ib) of the peak intensity (Ib) of the peak intensity (Ia) to the peak intensity (Ib) of the peak intensity (Ib) of the

[0039] The peak intensity ratio (Ia / Ib) is an index showing the balance between the concentrations of carbodiimide groups and ether groups in the polycarbodiimide compound (X). When the value of Ia / Ib is within the above range, the cured product of the resin composition using the polycarbodiimide compound (X) can maintain good low dielectric properties and can be imparted with good adhesion to metal foil.

[0040] (Other Component (d)) The polycarbodiimide compound (X) may be a reaction product of a polycarbodiimide (a), a PPE (b), an optional compound (c) having an unsaturated double bond, and another component (d) other than these. The other component (d) is preferably a compound having a functional group capable of reacting with an isocyanate group, and may be included in the raw material composition of the polycarbodiimide compound (X) within the scope that does not impair the effects of the present invention. The functional group capable of reacting with an isocyanate group is the same as that described above for the compound (c) having an unsaturated double bond. Examples of the other component (d) include alcohols such as 1-butanol, 1-hexanol, and 1-octanol; amines such as butylamine and cyclohexylamine; and carboxylic acids such as propionic acid and butyric acid.

[0041] [Method for Producing Polycarbodiimide Compound (X)] The method for producing the polycarbodiimide compound (X) is not particularly limited. For example, the polycarbodiimide compound (X) can be produced by heating a mixed raw material containing polycarbodiimide (a) and PPE (b) to cause a reaction. The mixed raw material may contain a compound (c) having an unsaturated double bond and other components, as necessary. Furthermore, a solvent and a catalyst may be used to improve the reaction efficiency.

[0042] A preferred embodiment of the method for producing the polycarbodiimide compound (X) includes, for example, a method in which a solvent, PPE (b), a compound having an unsaturated double bond (c), and a urethanization catalyst are added to and mixed with preheated polycarbodiimide (a), and the mixture is heated under a stream of an inert gas such as nitrogen.

[0043] The heating temperature during the reaction is preferably 50 to 120° C., more preferably 60 to 100° C., and even more preferably 70 to 90° C. The reaction time is preferably 1 to 48 hours, more preferably 2 to 36 hours, and even more preferably 3 to 30 hours.

[0044] Examples of the solvent include hydrocarbons and ketones, and among these, preferred are toluene, xylene, cyclohexanone, diisobutyl ketone, methyl isobutyl ketone, etc. The amount of the urethanization catalyst added is preferably 2 parts by mass or less, more preferably 0.05 to 1 part by mass, and even more preferably 0.1 to 0.5 parts by mass, per 100 parts by mass of the total of the polycarbodiimide (a), the PPE (b), and the compound having an unsaturated double bond (c).

[0045] Another preferred embodiment of the method for producing polycarbodiimide compound (X) is a method in which the constituent raw materials of polycarbodiimide (a), diisocyanate, PPE (b), and compound (c) having an unsaturated double bond are mixed, a carbodiimidization catalyst is added, and the mixture is heated under a stream of inert gas such as nitrogen. This method is a method for producing polycarbodiimide compound (X) by one-pot synthesis from diisocyanate without isolating polycarbodiimide (a). The heating temperature and reaction time during the reaction are the same as those in the production embodiment described above.

[0046] [Resin Composition] The resin composition of the present embodiment contains a polycarbodiimide compound (X) and a compound (A) having an unsaturated double bond. Such a resin composition can provide a cured resin product having a low dielectric constant and a low dielectric loss tangent, excellent low dielectric properties, and excellent adhesion to a metal foil.

[0047] (Compound (A) Having an Unsaturated Double Bond) The compound (A) having an unsaturated double bond preferably has a radically polymerizable carbon-carbon double bond, and examples thereof include (meth)acrylates, vinyl compounds, and maleimide compounds. The number of unsaturated double bonds in one molecule of the compound (A) having an unsaturated double bond may be one or more. The compound (A) having an unsaturated double bond may be used alone or in combination of two or more.

[0048] Examples of the compound (A) having an unsaturated double bond include compounds (modified PPE) in which the molecular end of PFE is modified with a substituent having an unsaturated double bond. Specific examples include styrene-modified PPE and (meth)acrylic-modified PPE. Other examples include triallyl isocyanurate, diallyl phthalate, and divinylbenzene. Furthermore, the compound (A) having an unsaturated double bond may be the same as the compound (c) having an unsaturated double bond described above. Among these, (meth)acrylic-modified PPE and triallyl isocyanurate are preferred from the viewpoint of obtaining a cured resin having excellent low dielectric properties through a reaction with the polycarbodiimide compound (X).

[0049] From the viewpoint of low dielectric properties of the resulting cured resin and good adhesion to the metal foil, the content of the compound (A) having an unsaturated double bond in the resin composition is preferably 50 to 98 parts by mass, more preferably 55 to 95 parts by mass, even more preferably 60 to 90 parts by mass, and even more preferably 65 to 80 parts by mass, per 100 parts by mass of the polycarbodiimide compound (X) and the compound (A) having an unsaturated double bond. That is, per 100 parts by mass of the polycarbodiimide compound (X) and the compound (A) having an unsaturated double bond, the content of the polycarbodiimide compound (X) is preferably 2 to 50 parts by mass, more preferably 5 to 45 parts by mass, even more preferably 10 to 40 parts by mass, and even more preferably 20 to 35 parts by mass.

[0050] (Radical Polymerization Initiator (B)) The resin composition of this embodiment preferably further contains a radical polymerization initiator (B). The radical polymerization initiator (B) promotes polymerization of a compound having an unsaturated double bond in the resin composition, and may be a photopolymerization initiator or a thermal polymerization initiator, and any known initiator can be used. The radical polymerization initiator may be added as a component separate from the resin composition when producing a cured product of the resin composition. From the viewpoint of ease of control of the polymerization reaction, the photopolymerization initiator is preferably one that can be used with ultraviolet irradiation with a wavelength of 380 nm or less, and the thermal polymerization initiator is preferably one that has a 10-hour half-life temperature in the range of 70 to 140°C.

[0051] Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-(2-oxo-2-phenylacetoxyethoxy)ethyl oxyphenylacetate, 2-(2-hydroxyethoxy)ethyl oxyphenylacetate, 2-hydroxy-2-methylpropiophenone, diethoxyacetophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropanone, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropanone, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone, benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl. Examples of photopolymerization initiators include benzoin ether, benzoin-n-butyl ether, benzoin phenyl ether, benzil dimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone-4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, methylphenyl glyoxylate, benzil, camphorquinone, etc. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination.

[0052] Examples of the thermal polymerization initiator include azo compounds; and organic peroxides such as hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, peroxydicarbonates, peroxyketals, and ketone peroxides. Specific examples include azobisisobutyronitrile, benzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoyl)peroxyhexane, tert-butylperoxybenzoate, tert butyl peroxide, cumene hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-dibutylperoxyhexane, 2,4-dichlorobenzoyl peroxide, 1,4-di(2-t-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, methyl ethyl ketone peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, etc. The thermal polymerization initiator may be used alone or in combination of two or more.

[0053] When the resin composition contains the radical polymerization initiator (B), the content thereof is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, and even more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass in total of the polycarbodiimide compound (X) and the compound (A) having an unsaturated double bond, from the viewpoint of an appropriate polymerization rate.

[0054] (Other Components (C)) The resin composition may contain other components (C) in addition to the polycarbodiimide compound (X), the compound (A) having an unsaturated double bond, and the radical polymerization initiator (B), depending on the ease of handling and its application. Examples of the other components (C) include colorants such as pigments and dyes, silane coupling agents, fillers, etc. A solvent may also be contained. Examples of the solvent include the same solvents as those listed in the description of the method for producing the polycarbodiimide compound (X) above.

[0055] The resin composition may contain other components (C) in an amount within a range that does not impair the effects of the present invention. The total amount of the polycarbodiimide compound (X) and the compound (A) having an unsaturated double bond in the resin composition (excluding the solvent) is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more.

[0056] The content of the solvent in the resin composition is within a range that does not impair the effects of the present invention, and is preferably 60% by mass or less, more preferably 10 to 55% by mass, and even more preferably 10 to 50% by mass, from the viewpoint of uniform mixing and moldability of the resin composition, etc. When the resin composition contains a solvent, the solvent is preferably removed by volatilization during or after curing of the resin composition.

[0057] The components of the resin composition are preferably mixed uniformly, and the mixing order is not limited. The components may be mixed in advance or immediately before curing the resin composition. For example, the radical polymerization initiator (B) may be added to a premix in which components other than the radical polymerization initiator (B) are mixed in advance, immediately before curing the resin composition.

[0058] [Cured Resin Product] The cured resin product of this embodiment is a cured product of the above-described resin composition. The resin composition can be cured by a known method such as irradiation with active energy rays (e.g., light such as ultraviolet rays, or electron beams) or heating.

[0059] When the resin composition is cured by heating, the heating temperature and heating time are appropriately set depending on the raw material composition of the resin composition, the form of the cured product, etc. The heating temperature is preferably 100 to 250°C, more preferably 120 to 220°C, and even more preferably 150 to 200°C, and may be increased in stages. The heating time is preferably 5 to 180 minutes, more preferably 10 to 120 minutes, and even more preferably 20 to 90 minutes.

[0060] The resin composition of this embodiment is suitable for use as an insulating material for electronic circuit boards because the cured product has good low dielectric properties and excellent adhesion to metal foil. Examples of the metal foil include metal foils used in copper-clad laminates and resin-coated metal foils, specifically copper foil, aluminum foil, etc. For example, a copper-clad laminate having excellent adhesion to the copper foil can be produced by placing a semi-cured resin composition on copper foil and thermally curing it using a heat press.

[0061] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples, and various modifications are possible within the scope of the gist of the present invention.

[0062] [Compounds Used] Details of the raw material compounds used are shown below. Note that the molecular weight and weight average molecular weight are calculated values ​​or catalog values. HMDI: dicyclohexylmethane-4,4'-diisocyanate; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 262.35 IPDI: isophorone diisocyanate; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 222.29 TODI: o-tolidine diisocyanate; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 264.28 MDI: "Millionate (registered trademark) NM" manufactured by Tosoh Corporation; mixture of 2,4'-MDI and 4,4'-MDI (molar ratio of 54:46), molecular weight 250.25 TDI: tolylene-2,4-diisocyanate; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 174.16 CHI: cyclohexyl isocyanate; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 125.17 MPPO: 3-methyl-1-phenyl-2-phospholene-1-oxide; manufactured by Tokyo Chemical Industry Co., Ltd., carbodiimide formation catalyst SA90: "NORYL (registered trademark) SA90"; manufactured by SABIC Corporation, hydroxyl group-terminated PPE, hydroxyl group equivalent weight 852 g / mol, number average molecular weight 2346 4-HBA: 4-hydroxybutyl acrylate; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 144.17 2-HEMA: 2-hydroxyethyl methacrylate; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 130.14 1-octanol; manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 130.23 Toluene; manufactured by Tokyo Chemical Industry Co., Ltd. Cyclohexanone; manufactured by Tokyo Chemical Industry Co., Ltd. Triethylenediamine; manufactured by Tokyo Chemical Industry Co., Ltd., urethane formation catalyst SA9000: "NORYL (registered trademark) SA9000"; manufactured by SABIC, methacrylic-modified PPE, theoretical molecular weight 1700 TAIC: triallyl isocyanurate; manufactured by Tokyo Chemical Industry Co., Ltd. DTBP: di-tert-butyl peroxide; manufactured by Tokyo Chemical Industry Co., Ltd., radical polymerization initiator DCC: dicyclohexylcarbodiimide; manufactured by Tokyo Chemical Industry Co., Ltd.

[0063] [Analysis and Measurement] The analysis and measurement methods used in the following Synthesis Examples and Production Examples are as follows: (Infrared absorption (IR) spectrum measurement) The reaction solution was measured using a Fourier transform infrared spectrophotometer "FT / IR-6100" (manufactured by JASCO Corporation) and the 2120 cm spectrum derived from the carbodiimide group was measured. －１ The formation of polycarbodiimide was confirmed by the appearance of a peak around 2200 to 2300 cm derived from the isocyanate group in the IR spectrum. －１ The disappearance of the carbodiimide group was confirmed by the disappearance of the peak at 2100 to 2200 cm －１ In the production examples, the maximum peak intensity of the IR spectrum of the polycarbodiimide compound was adjusted to 60 to 70% in transmittance, and the disappearance of the peak of 2100 to 2200 cm derived from the carbodiimide group was confirmed. －１ and the peak intensity (Ia) of 1150 to 1200 cm due to the ether group of polyphenylene ether (b). －１ The ratio (Ia / Ib) of the peaks (Ia) and (Ib) was calculated.

[0064] (NCO Content and Average Degree of Polymerization of Carbodiimide Groups (NCN)) A toluene solution of di-n-butylamine was added to an isocyanate-terminated polycarbodiimide to cause a reaction, and the remaining di-n-butylamine was subjected to back-titration by potentiometric titration using an automatic titrator "COM-1700A" (manufactured by HIRANUMA Corporation) to determine the NCO content, from which the average degree of polymerization of NCN was calculated.

[0065] (Number average molecular weight of SA90) Measurement was carried out by gel permeation chromatography (GPC) under the following measurement conditions. <Measurement conditions> - Instrument used: "Prominence (registered trademark) CTO20A, LC20AB, SIL20AC", manufactured by Shimadzu Corporation - Column used: "KF-804L", "KF-806M", manufactured by Resonac Corporation - RI detector: "RID-10A", manufactured by Shimadzu Corporation - UV-VIS detector: "SPD-20AV", manufactured by Shimadzu Corporation - Eluent: tetrahydrofuran - Standard sample: polystyrene

[0066] Synthesis of Polycarbodiimide (a) Synthesis Example 1 200 g of HMDI and 1 g of MPPO were placed in a 0.3 L reaction vessel equipped with a reflux condenser and a stirrer, and the mixture was reacted at 175° C. for 9 hours under a nitrogen stream to synthesize polycarbodiimide (a1) (NCN average degree of polymerization: 2.0), which was a polymer of HMDI and had isocyanate groups at both ends.

[0067] Synthesis Examples 2 to 6 Using the raw material compositions, reaction temperatures and reaction times shown in Table 1, polycarbodiimides (a2) to (a6) each having isocyanate groups at both ends were synthesized in the same manner as in Synthesis Example 1.

[0068]

[0069] [Production of Polycarbodiimide Compound (X)] (Production Example 1) 30.0 g of polycarbodiimide (a1) was placed in a 0.3 L reaction vessel equipped with a reflux condenser and a stirrer and heated to 110°C. 73.4 g of toluene as a solvent, 36.6 g of SA90 as PPE (b) (0.5 mol per mol of polycarbodiimide (a1)), 6.8 g of 4-HBA as ethylenically unsaturated compound (c) (1.1 mol per mol of polycarbodiimide (a1)), and 0.3 g of triethylenediamine as a urethanization catalyst were added and stirred. The reaction was carried out at 80°C for 24 hours under a nitrogen stream. After confirming the disappearance of the isocyanate groups, the mixture was cooled to room temperature (25°C) to obtain polycarbodiimide compound (X1). In the IR spectrum of polycarbodiimide compound (X1), a peak at 2100 to 2200 cm originating from the carbodiimide group was observed. －１ and the peak intensity of 1150 to 1200 cm due to the ether group of PPE (b). －１ The ratio (Ia / Ib) of the peak intensities (Ia) and (Ib) was 0.75.

[0070] (Production Examples 2 to 8) Using the raw material compositions shown in Table 2, polycarbodiimide compounds (X2) to (X8) were produced in the same manner as in Production Example 1.

[0071]

[0072] Production Example 9 A 0.3 L reaction vessel equipped with a reflux condenser and a stirrer was charged with 40.0 g of TODI, 34.6 g of SA90 as PPE (b) (0.5 mol per mol of polycarbodiimide (a) obtained by polymerization of TODI), and 10.9 g of 4-HBA as ethylenically unsaturated compound (c) (1.1 mol per mol of polycarbodiimide (a) obtained by polymerization of TODI), and the mixture was stirred at 50°C for 3 hours under a nitrogen stream. 0.4 g of MPPO was added thereto, and the mixture was reacted at 80°C for 24 hours. After confirming the disappearance of the isocyanate groups, the mixture was cooled to room temperature (25°C) to obtain polycarbodiimide compound (X9). Although polycarbodiimide (a) obtained by polymerization of TODI was not isolated, in the above raw material composition, 3 moles of carbodiimide groups are produced by decarboxylation from 4 moles of TODI, and therefore the theoretical mass is 35.0 g. This theoretical mass is regarded as the content of polycarbodiimide (a) in the raw material composition of polycarbodiimide compound (X9). In the IR spectrum of polycarbodiimide compound (X9), the peak at 2100 to 2200 cm originating from carbodiimide groups is －１ and the peak intensity of 1150 to 1200 cm due to the ether group of PPE (b). －１ The ratio (Ia / Ib) of the peak intensities (Ia) and (Ib) was 0.80.

[0073] (Production Examples 10 to 12 and Comparative Production Example 1) Using the raw material compositions shown in Table 3, polycarbodiimide compounds (X10) to (X12) and (X'1) were produced in the same manner as in Production Example 9.

[0074]

[0075] Comparative Production Example 2 Production of Monocarbodiimide-Modified PPE (Y) 50.0 g of SA90, 12.2 g of DCC, and 63.0 g of cyclohexanone as a solvent were placed in a 0.3 L reaction vessel equipped with a reflux condenser and a stirrer, and the mixture was reacted at 150°C for 10 hours under a nitrogen stream. After confirming the disappearance of the carbodiimide groups, the mixture was cooled to room temperature (25°C) to obtain monocarbodiimide-modified PPE (Y).

[0076] Comparative Production Example 3 Production of Polycarbodiimide (Z) Not Having a PPE-Based Structure 200 g of HMDI, 20.0 g of CHI, and 1 g of MPPO were placed in a 0.5 L reaction vessel equipped with a reflux condenser and a stirrer, and reacted at 175° C. for 72 hours under a nitrogen stream. After confirming the disappearance of the isocyanate groups, the mixture was cooled to room temperature (25° C.) to obtain Polycarbodiimide (Z) not having a PPE-based structure.

[0077] [Production of Resin Composition] (Example 1) 10 parts by mass (based on the mass of nonvolatile matter) of polycarbodiimide compound (X1), 63 parts by mass of SA9000 and 27 parts by mass of TAIC as ethylenically unsaturated compounds (A), 2 parts by mass of DTBP as radical polymerization initiator (B), and 100 parts by mass of toluene as a solvent were mixed and stirred at 20°C for 2 hours to produce a resin composition having a resin component concentration of 50% by mass.

[0078] Examples 2 to 14 Using the raw material compositions shown in Table 4, and following the same procedures as in Example 1, each resin composition was produced.

[0079] Comparative Example 1 10 parts by mass of polycarbodiimide compound (X′1), 69 parts by mass of SA9000 and 27 parts by mass of TAIC as ethylenically unsaturated compounds (A), 2 parts by mass of DTBP as radical polymerization initiator (B), and 100 parts by mass of toluene as a solvent were mixed and stirred at 20° C. for 2 hours to produce a resin composition having a resin component concentration of 50% by mass.

[0080] Comparative Examples 2 to 5 Using the raw material compositions shown in Table 5, and following the same procedure as in Comparative Example 1, each resin composition was produced.

[0081] [Evaluation of Resin Compositions] The adhesive strength, dielectric constant, and dielectric loss tangent of each of the resin compositions produced in the above Examples and Comparative Examples were measured as follows. The results are shown in Tables 4 and 5. Note that the resin composition of Comparative Example 2 could not be evaluated because no cured product was obtained.

[0082] (Adhesion strength) The resin composition was poured into a plastic container and then impregnated into a glass cloth (2116, NE Glass, manufactured by Nittobo Co., Ltd.). The excess was removed with a glass rod and then dried at 105 ° C. for 30 minutes to obtain a semi-cured product. Two sheets (7 mm x 8 mm, thickness 0.3 mm) of the obtained semi-cured product were stacked and sandwiched between the roughened surfaces of copper foil ("SI-VSP (registered trademark)-AM2R", manufactured by Mitsui Mining & Smelting Co., Ltd.; the same applies hereinafter). A copper-clad laminate was produced by hot pressing in a vacuum press (pressure 3.5 MPa) at 170 ° C. for 30 minutes and then at 190 ° C. for 30 minutes. A 10 mm wide cut was made in the copper foil of the copper-clad laminate with a cutter and fixed to a stainless steel plate with double-sided tape. The load required to peel the copper foil was measured using a desktop precision universal testing machine ("Autograph AGS-100NX", manufactured by Shimadzu Corporation), and the average value of the load measurements at peel lengths of 20 mm to 40 mm was taken as the adhesion strength. Tables 4 and 5 also show evaluations based on the adhesion strength of Comparative Example 5. The evaluation criteria were as follows: A: an increase in adhesion strength of 7% or more; B: an increase in adhesion strength of 3% or more but less than 7%; and C: an increase in adhesion strength of less than 3%.

[0083] (Dielectric Constant and Dielectric Loss Tangent) The resin composition was dried at 105°C for 30 minutes to obtain a semi-cured product. Two sheets (7mm x 8mm, thickness 0.3mm) cut from the obtained semi-cured product were stacked and sandwiched between Naflon (registered trademark) PTFE sheets ("TOMBO (registered trademark) No. 9000", manufactured by Nichias Corporation). The sheets were then heat-pressed in a vacuum press (pressure 3.5MPa) at 170°C for 30 minutes and then at 190°C for 30 minutes to obtain a cured resin product. A sample (30mm x 30mm, thickness 0.29mm) cut from the cured resin product with a cutter was measured for the dielectric constant and dielectric loss tangent at a resonance peak near 60GHz using a dielectric constant measuring device ("PS-X10-100", "PNA Microwave Network Analyzer N5227A", manufactured by Keysight Technologies).

[0084]

[0085]

[0086] As can be seen from the evaluation results shown in Tables 4 and 5, the cured resin compositions (Examples 1 to 14) containing polycarbodiimide compounds having a structure based on the specified polycarbodiimide of the present invention and a structure based on PPE were found to have low dielectric constants and dielectric loss tangents even in the high frequency band of 60 GHz, and to have excellent adhesion to metal foil while maintaining low dielectric properties.

Claims

1. A polycarbodiimide compound having a structure based on polycarbodiimide (a) formed by polymerization of diisocyanate and a structure based on polyphenylene ether (b), wherein the mass ratio (b / a) of the structure based on polyphenylene ether (b) to the structure based on polycarbodiimide (a) is 0.20 to 1.

50.

2. The polycarbodiimide compound according to claim 1, wherein the polycarbodiimide (a) has an average degree of polymerization of the carbodiimide groups of 2.0 to 15.

0.

3. The polycarbodiimide compound according to claim 1 or 2, wherein the diisocyanate is at least one selected from the group consisting of alicyclic diisocyanates and aromatic diisocyanates.

4. The polycarbodiimide compound according to claim 3, wherein the alicyclic diisocyanate is at least one selected from the group consisting of dicyclohexylmethane-4,4'-diisocyanate and isophorone diisocyanate, and the aromatic diisocyanate is at least one selected from the group consisting of o-tolidine diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and tolylene-2,4-diisocyanate.

5. The polycarbodiimide compound according to any one of claims 1 to 4, wherein the polyphenylene ether (b) has a number average molecular weight of 1,500 to 3,000.

6. The polycarbodiimide compound according to any one of claims 1 to 5, wherein the structure based on the polycarbodiimide (a) and the structure based on the polyphenylene ether (b) are bonded via a urethane bond.

7. In the infrared absorption spectrum, the peak at 2100-2200 cm originating from the carbodiimide group －１ and the peak intensity (Ia) of 1150 to 1200 cm derived from the ether group of the polyphenylene ether (b). －１ 7. The polycarbodiimide compound according to claim 1, wherein the ratio (Ia / Ib) of the peak intensity (Ib) of the peak intensity (Ia) to the peak intensity (Ib) of the peak intensity (Ib) of the polycarbodiimide compound according to claim 1 is 0.70 to 4.

00.

8. The polycarbodiimide compound according to any one of claims 1 to 7, which is a reaction product of the polycarbodiimide (a), the polyphenylene ether (b), and a compound (c) having an unsaturated double bond, wherein the compound (c) having an unsaturated double bond has a functional group capable of reacting with an isocyanate group.

9. The polycarbodiimide compound according to claim 8, wherein the polycarbodiimide (a) is present in an amount of 35 to 80 parts by mass per 100 parts by mass of the polycarbodiimide (a), the polyphenylene ether (b), and the compound having an unsaturated double bond (c).

10. The polycarbodiimide compound according to claim 8 or 9, wherein the functional group capable of reacting with an isocyanate group of the compound (c) having an unsaturated double bond is at least one selected from the group consisting of a hydroxyl group, an amino group, an isocyanate group, and a carboxy group.

11. The polycarbodiimide compound according to any one of claims 8 to 10, wherein the compound (c) having an unsaturated double bond is a hydroxyalkyl (meth)acrylate.

12. A resin composition comprising the polycarbodiimide compound according to any one of claims 1 to 11 and a compound (A) having an unsaturated double bond.

13. The resin composition according to claim 12, further comprising a radical polymerization initiator (B).

14. A cured resin product, which is a cured product of the resin composition according to claim 12 or 13.

15. An insulating material for electronic circuit boards, which is the resin composition according to claim 12 or 13.

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