JP7699997B2 - Phosphorus compound having an isocyanurate ring, synthesis method thereof, and use of said phosphorus compound having an isocyanurate ring - Google Patents

Description

The present invention relates to a novel phosphorus compound having an isocyanurate ring, a method for synthesizing the phosphorus compound having an isocyanurate ring, and the use of the phosphorus compound having an isocyanurate ring.

2. Description of the Related Art In recent years, electronic devices have become smaller and more sophisticated, and in multilayer printed wiring boards, build-up layers have become more numerous, and there is a demand for finer and denser wiring.
In particular, in high frequency applications, insulating materials (resin materials) with low dielectric tangents are required to reduce transmission loss of electrical signals. In addition to electrical properties, such resin materials are also required to have flame retardancy when cured, and flame retardants are being investigated.

Flame retardants used in resin materials include inorganic flame retardants and organic flame retardants.
Inorganic flame retardants have excellent dielectric properties, but because they are water absorbent and hydrolyzable, the cured product is prone to deterioration over time, making them unsuitable for use in electrical and electronic devices that require long-term reliability.
On the other hand, phosphorus compounds, which are organic flame retardants, have plasticity, so there was a problem that increasing the amount of phosphorus compound added to enhance flame retardancy would impair the mechanical strength of the cured product.

Various substances have been investigated as flame retardants to solve these problems. Among them, phosphorus compounds having radically polymerizable groups in the molecule are expected to improve low thermal expansion, heat resistance, and mechanical strength.
For example, (2,5-dimethacryloxyphenyl)diphenylphosphine oxide and its analogues are proposed as flame retardants in Patent Document 1. However, resin compositions using these compounds still have room for improvement in terms of low thermal expansion, heat resistance, mechanical strength, and electrical properties.

International Publication No. 2013/114866

The present invention aims to provide a novel phosphorus compound having an isocyanurate ring, a method for synthesizing the phosphorus compound having an isocyanurate ring, a flame retardant containing the phosphorus compound having an isocyanurate ring, and a resin composition containing the phosphorus compound having an isocyanurate ring and a resin component.
A further object of the present invention is to provide a prepreg, a resin-coated metal foil, a thermosetting resin film, a metal-clad laminate, a printed wiring board, and an adhesive, which use the resin composition.

Means for Solving the Problems The present inventors have conducted intensive research to solve the above problems, and as a result have found that the desired object can be achieved by a phosphorus compound having an isocyanurate ring obtained by reacting a certain type of phosphorus compound with a certain type of isocyanurate compound, thereby completing the present invention.
That is, a first aspect of the present invention is a phosphorus compound having an isocyanurate ring represented by chemical formula (I).

（式中、Ｒ^１は、炭素数１～２０のアルキル基、アリール基、ベンジル基を表し、Ｒ^２は、式（１）で示される基を表す。或いは、Ｒ^１およびＲ^２が連結して環を形成してもよい。Ｒ^３は、同一または異なって、炭素数２～２０のアルケニル基、炭素数２～２０のアルキニル基を表す。Ｒ^４は、同一または異なって、水素原子、炭素数１～２０のアルキル基、アリール基、ベンジル基、炭素数２～２０のアルケニル基、炭素数２～２０のアルキニル基を表す。Ｙは、同一または異なって、炭素数１～２０のアルキレン基を表す。）

(In the formula, R ¹ represents an alkyl group, an aryl group, or a benzyl group having 1 to 20 carbon atoms, and R ² represents a group represented by formula (1). Alternatively, R ¹ and R ² may be linked to form a ring. R ³ may be the same or different and represent an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms. R ⁴ may be the same or different and represent a hydrogen atom, an alkyl group, an aryl group, a benzyl group, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms. Y may be the same or different and represent an alkylene group having 1 to 20 carbon atoms.)

（式中、Ｒ^３、Ｒ^４およびＹは、前記と同様である。）

(In the formula, R ³ , R ⁴ and Y are the same as defined above.)

The second invention is a method for synthesizing a phosphorus compound having an isocyanurate ring according to the first invention, which is characterized by reacting a phosphorus compound represented by chemical formula (II) with an isocyanurate compound represented by chemical formula (III).

（式中、Ｒ^１は、前記と同様であり、Ｒ^８は、－Ｙ－Ｘを表す。或いは、Ｒ^１およびＲ^８が連結して環を形成してもよい。Ｙは、前記と同様である。Ｘは、同一または異なって、フッ素原子、塩素原子、臭素原子、ヨウ素原子、メシルオキシ基（ＯＭｓ）、トシルオキシ基（ＯＴｓ）、トリフルオロメタンスルホニルオキシ基（ＯＴｆ）を表す。）

(In the formula, R ¹ is the same as defined above, R ⁸ represents -Y-X, or R ¹ and R ⁸ may be linked to form a ring. Y is the same as defined above. X may be the same or different and represents a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a mesyloxy group (OMs), a tosyloxy group (OTs), or a trifluoromethanesulfonyloxy group (OTf).)

（式中、Ｒ^３およびＲ^４は、前記と同様である。）

(In the formula, ^R3 and ^R4 are the same as defined above.)

A third invention is a flame retardant containing the phosphorus compound having an isocyanurate ring according to the first invention.
A fourth invention is a resin composition containing the phosphorus compound having an isocyanurate ring of the first invention and a resin component.
A fifth invention is the resin composition according to the fourth invention, characterized in that the resin component is a polyphenylene ether resin.
A sixth invention is a prepreg comprising the resin composition of the fourth or fifth invention and a substrate.
A seventh invention is a resin-coated metal foil comprising a resin layer containing the resin composition of the fourth or fifth invention or a semi-cured product of the resin composition, and a metal foil.
An eighth invention is a thermosetting resin film formed from the resin composition of the fourth invention or the fifth invention.
A ninth invention is a metal-clad laminate comprising an insulating layer containing a cured product of the resin composition of the fourth invention or the fifth invention, and a metal foil.
A tenth invention is a printed wiring board comprising an insulating layer containing a cured product of the resin composition of the fourth or fifth invention, or a cured product of the thermosetting resin film of the eighth invention, and wiring.
An eleventh invention is an adhesive comprising the resin composition according to the fourth or fifth invention.

The phosphorus compound having an isocyanurate ring of the present invention is a novel phosphorus compound having an isocyanurate ring, and is expected to be used as a flame retardant for resins.
Since the phosphorus compound having an isocyanurate ring of the present invention has an isocyanurate ring and an unsaturated bond group in the molecule, when used as a raw material for a resin (resin material), it is expected to give a cured product having low thermal expansion, heat resistance, adhesiveness (adhesion), mechanical properties, electrical properties and flame retardancy superior to those obtained when a conventional phosphorus compound is used. Therefore, the resin composition of the present invention can be suitably used as a material for printed wiring boards and the like.
Furthermore, the adhesive of the present invention is expected to have excellent flame retardancy, low thermal expansion, heat resistance, adhesiveness, mechanical properties, and electrical properties.

1 is an IR spectrum chart of the white powder obtained in Example 1. 1 is an IR spectrum chart of the white powder obtained in Example 2.

(1. Phosphorus Compound Having an Isocyanurate Ring)
The present invention relates to a phosphorus compound having an isocyanurate ring represented by the above-mentioned chemical formula (I) (hereinafter, sometimes referred to as the "phosphorus compound of the present invention"). The phosphorus compound of the present invention includes a phosphorus compound represented by the chemical formula (I-1) and a phosphorus compound represented by the chemical formula (I-2).

（式中、Ｒ^１は、炭素数１～２０のアルキル基、アリール基、ベンジル基を表す。Ｒ^３は、同一または異なって、炭素数２～２０のアルケニル基、炭素数２～２０のアルキニル基を表す。Ｒ^４は、同一または異なって、水素原子、炭素数１～２０のアルキル基、アリール基、ベンジル基、炭素数２～２０のアルケニル基、炭素数２～２０のアルキニル基を表す。Ｙは、同一または異なって、炭素数１～２０のアルキレン基を表す。）

(In the formula, R ¹ represents an alkyl group, an aryl group, or a benzyl group having 1 to 20 carbon atoms; R ³ is the same or different and represents an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms; R ⁴ is the same or different and represents a hydrogen atom, an alkyl group, an aryl group, a benzyl group, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms; and Y is the same or different and represents an alkylene group having 1 to 20 carbon atoms.)

（式中、Ｒ^３は、炭素数２～２０のアルケニル基、炭素数２～２０のアルキニル基を表す。Ｒ^４は、水素原子、炭素数１～２０のアルキル基、アリール基、ベンジル基、炭素数２～２０のアルケニル基、炭素数２～２０のアルキニル基を表す。Ｙは、炭素数１～２０のアルキレン基を表す。）

(In the formula, ^R3 represents an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms. ^R4 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, a benzyl group, an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms. Y represents an alkylene group having 1 to 20 carbon atoms.)

Examples of the phosphorus compound represented by chemical formula (I-1) include the phosphorus compounds represented by chemical formulas (I-1-1) to (I-1-12).
Examples of the phosphorus compound represented by the chemical formula (I-2) include the phosphorus compounds represented by the chemical formulas (I-2-1) to (I-2-3).

Examples of the alkyl group having 1 to 20 carbon atoms represented by ^R1 and ^R4 include linear or branched alkyl groups having 1 to 20 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group.

Examples of the aryl group represented by ^R1 and ^R4 include a phenyl group, a 2-tolyl group, a 3-tolyl group, a 4-tolyl group, a 2,3-xylyl group, a 2,4-xylyl group, a 2,5-xylyl group, a 2,6-xylyl group, a 3,4-xylyl group, a 3,5-xylyl group, a 2,4,6-trimethylphenyl group, a 2,3,5-trimethylphenyl group, a 2,3,6-trimethylphenyl group, a 2,4,5-trimethylphenyl group, a 2,3,5,6-tetramethylphenyl group, a biphenyl group, a 1-naphthyl group, and a 2-naphthyl group.

As described above, ^R1 and ^R2 may be linked to form a ring. An example of a ring formed by linking ^{R1 and R2} is a phosphorus compound represented by the chemical formula (I- ² ).

Examples of the alkenyl group having 2 to 20 carbon atoms represented by ^R3 and ^R4 include linear or branched alkenyl groups having 2 to 20 carbon atoms, and specific examples thereof include a vinyl group, an allyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, and an icosenyl group.

Examples of the alkynyl group having 2 to 20 carbon atoms represented by ^R3 and ^R4 include linear or branched alkynyl groups having 2 to 20 carbon atoms, and specific examples thereof include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, a pentynyl group, a hexynyl group, a heptynyl group, an octynyl group, a nonynyl group, a decynyl group, an undecynyl group, a dodecynyl group, a tridecynyl group, a tetradecynyl group, a pentadecynyl group, a hexadecynyl group, a heptadecynyl group, an octadecynyl group, a nonadecynyl group, and an icosynyl group.

Examples of alkylene groups having 1 to 20 carbon atoms represented by Y include linear or branched alkylene groups having 1 to 20 carbon atoms, such as methylene, methylmethylene, dimethylene, trimethylene, ethylmethylene, dimethylmethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, and dodecamethylene.

In the phosphorus compound represented by the chemical formula (I-1), preferred substituents are as follows.
R ¹ is preferably an alkyl group having 1 to 5 carbon atoms, a phenyl group, a 2,6-xylyl group, a biphenyl group, a 1-naphthyl group, a 2-naphthyl group, or a benzyl group.
R ³ and R ⁴ are the same and preferably an alkenyl group having 2 to 4 carbon atoms or an alkynyl group having 2 to 4 carbon atoms.
Y is preferably a methylene group.

In the phosphorus compound represented by the chemical formula (I-2), preferred substituents are as follows.
R ³ and R ⁴ are the same and preferably an alkenyl group having 2 to 4 carbon atoms or an alkynyl group having 2 to 4 carbon atoms.
Y is preferably a methylene group.

(2. Method for synthesizing phosphorus compounds of the present invention)
The phosphorus compound of the present invention can be synthesized by reacting a phosphorus compound represented by chemical formula (II) with an isocyanurate compound represented by chemical formula (III).

The phosphorus compounds represented by chemical formula (II) include the phosphorus compounds represented by chemical formula (II-1) and the phosphorus compounds represented by chemical formula (II-2).

（式中、Ｒ^１およびＹは、前記と同様である。Ｘは、同一または異なって、フッ素原子、塩素原子、臭素原子、ヨウ素原子、メシルオキシ基（ＯＭｓ）、トシルオキシ基（ＯＴｓ）、トリフルオロメタンスルホニルオキシ基（ＯＴｆ）を表す。）

(In the formula, ^R1 and Y are the same as defined above. X may be the same or different and represents a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a mesyloxy group (OMs), a tosyloxy group (OTs), or a trifluoromethanesulfonyloxy group (OTf).)

（式中、Ｙは、前記と同様である。Ｘは、フッ素原子、塩素原子、臭素原子、ヨウ素原子、メシルオキシ基（ＯＭｓ）、トシルオキシ基（ＯＴｓ）、トリフルオロメタンスルホニルオキシ基（ＯＴｆ）を表す。）

(In the formula, Y is the same as defined above. X represents a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a mesyloxy group (OMs), a tosyloxy group (OTs), or a trifluoromethanesulfonyloxy group (OTf).)

In the chemical formula (II), as described above, ^R1 and ^R8 may be linked to form a ring. An example of a ring formed by linking ^{R1 and R8} is a phosphorus compound represented by the chemical formula (II- ² ).

Examples of the phosphorus compound represented by the chemical formula (II-1) include the phosphorus compounds represented by the chemical formulas (II-1-1) to (II-1-10).
Examples of the phosphorus compound represented by the chemical formula (II-2) include the phosphorus compounds represented by the chemical formulas (II-2-1) to (II-2-4).

These phosphorus compounds can be prepared by purchasing commercially available reagents, or can be synthesized according to the methods described in, for example, Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 44B(6), 1248-1251(2005), RSC Advances, 6(57), 52485-52394(2016), Youji Huaxue, 13(5), 527-532(1993), Agricultural and Biological Chemistry, 46(2), 411-418(1982), etc.

Examples of the isocyanurate compound represented by chemical formula (III) include the isocyanurate compounds represented by chemical formulas (III-1) to (III-3).

These isocyanurate compounds can be purchased commercially and used, or can be synthesized, for example, according to the method described in JP 2016-216399 A.

Reaction scheme (A) shows an example of synthesizing a phosphorus compound represented by chemical formula (I-1) by reacting a phosphorus compound represented by chemical formula (II-1) with an isocyanurate compound represented by chemical formula (III).
In addition, an example of synthesizing a phosphorus compound represented by chemical formula (I-2) by reacting a phosphorus compound represented by chemical formula (II-2) with an isocyanurate compound represented by chemical formula (III) is shown in reaction scheme (B).

（式中、Ｒ^１、Ｒ^３、Ｒ^４、ＹおよびＸは、前記と同様である。）

(In the formula, R ¹ , R ³ , R ⁴ , Y and X are the same as defined above.)

（式中、Ｒ^３、Ｒ^４、ＹおよびＸは、前記と同様である。）

(In the formula, R ³ , R ⁴ , Y and X are the same as defined above.)

In the reaction scheme (A), the amount (charge amount) of the isocyanurate compound represented by the chemical formula (III) is preferably set at an appropriate ratio in the range of 2 to 4 times the molar amount of the phosphorus compound represented by the chemical formula (II-1).
In the reaction scheme (B), the amount (charge amount) of the isocyanurate compound represented by the chemical formula (III) is preferably set at an appropriate ratio in the range of 1 to 2 times the molar amount of the phosphorus compound represented by the chemical formula (II-2).

In reaction schemes (A) and (B), it is preferable to use a base (a) to remove the acid by-product generated as the reaction proceeds. If necessary, a reaction catalyst (b) and a reaction solvent (c) may also be used appropriately.

Examples of bases (A) include trimethylamine, triethylamine, N,N-diisopropylethylamine, diazabicyclononene, diazabicycloundecene, pyridine, imidazole, sodium hydride, potassium hydride, lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, cesium hydrogen carbonate, trilithium phosphate, trisodium phosphate, tripotassium phosphate, tricesium phosphate, dilithium hydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dicesium hydrogen phosphate, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, cesium dihydrogen phosphate, lithium acetate, sodium acetate, potassium acetate, cesium acetate, sodium alkoxide, potassium alkoxide, and potassium t-butoxide. These may be used alone or in combination of two or more.

In the reaction scheme (A), the amount of the base (A) used (charged amount) is preferably an appropriate ratio in the range of 2 to 5 times the molar amount of the phosphorus compound represented by the chemical formula (II-1).
In the reaction scheme (B), the amount of the base (A) used (charged amount) is preferably an appropriate ratio in the range of 1 to 2.5 times the molar amount of the phosphorus compound represented by the chemical formula (II-2).

Examples of reaction catalysts (b) include alkali metal iodide salts such as lithium iodide, sodium iodide, and potassium iodide. These may be used alone or in combination of two or more.

In the reaction scheme (A), the amount of the reaction catalyst (ii) used (charged amount) is preferably an appropriate ratio in the range of 0.01 to 0.3 times the molar amount of the phosphorus compound represented by the chemical formula (II-1).
In the reaction scheme (B), the amount of the reaction catalyst (ii) used (charged amount) is preferably an appropriate ratio in the range of 0.01 to 0.3 times the molar amount of the phosphorus compound represented by the chemical formula (II-2).

The reaction solvent (iii) is not particularly limited as long as it does not inhibit the reaction, and examples thereof include
Examples of the solvent include tetrahydrofuran, dioxane, ethyl acetate, acetonitrile, benzene, toluene, xylene, dichloromethane, chloroform, carbon tetrachloride, dimethylformamide, dimethylacetamide, dimethylsulfoxide, hexamethylphosphoric triamide, and water. If necessary, these can be combined and used in appropriate amounts.

In reaction schemes (A) and (B), the reaction temperature is preferably set in the range of 50 to 140°C. The reaction time is set appropriately depending on the reaction temperature, but is preferably set in the range of 1 to 30 hours.

After completion of the reaction, the target phosphorus compound of the present invention can be isolated from the obtained reaction liquid (reaction mixture) by, for example, concentrating the reaction liquid by distilling off the reaction solvent or by a solvent extraction method.
If necessary, the product can be further purified by washing with water or the like, treatment with activated carbon, silica gel chromatography, recrystallization or the like.

(3. Flame retardant and resin composition)
The flame retardant and resin composition of the present invention contain the phosphorus compound of the present invention. The phosphorus compound of the present invention has a high flame retardant effect, so it can be suitably used as a flame retardant for resins. By containing the phosphorus compound of the present invention in the resin composition, the cured product (molded product) of the resin composition shows excellent flame retardancy.
In addition to the phosphorus compound and resin component of the present invention, the resin composition of the present invention may contain other flame retardants, polymerizable components, polymerization initiators, reactive diluents, fluororesins, inorganic fillers, and additives as necessary. In the present invention, the resin composition means the state of the mixture before curing.

[Resin component]
The resin component (including uncured and semi-cured resins) used in the resin composition of the present invention is not particularly limited as long as it is one that is commonly used as a material for a resin molded product.
Examples of the resin component include polyethylene resin, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, polyisoprene resin, polybutadiene resin, polystyrene resin, impact-resistant polystyrene resin, acrylonitrile-styrene resin (AS resin), acrylonitrile-butadiene-styrene resin (ABS resin), methyl methacrylate-butadiene-styrene resin (MBS resin), methyl methacrylate-acrylonitrile-butadiene-styrene resin (MABS resin), acrylonitrile-acrylic rubber-styrene resin (AAS resin), polymethyl (meth)acrylate resin, polyester resin (polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate, etc.), unsaturated polyester resin, polyesterimide resin, polyketone resin, polycarbonate resin, polyamide resin, polyimide resin, polyamideimide resin, polycarbodiimide resin, polyetherimide resin, polyetherketone resin, polyetheretherketone resin (PEEK resin), polyethersulfone resin, polythioethersulfone resin, polysulfone resin, polyphenylene sulfide resin, polyethernitrile resin, polyarylate resin, polybenzimidazole resin, benzoxazine resin, liquid crystal polymer resin, silicone resin, epoxy resin, polyurethane resin, phenol resin, melamine resin, urea resin, diallylphthalate resin, etc. These may be used alone or in combination of two or more.

The amount of the phosphorus compound of the present invention in the resin composition of the present invention is not particularly limited, and is 0.1 to 200 parts by weight, preferably 0.5 to 100 parts by weight, and more preferably 1 to 80 parts by weight, per 100 parts by weight of the resin component.

[Other flame retardants]
In the resin composition of the present invention, a flame retardant other than the phosphorus compound of the present invention (other flame retardant) may be used in combination.
Other flame retardants include, for example, phosphate ester compounds, phosphazene compounds, phosphite ester compounds, phosphine compounds, melamine phosphate, phosphoric acid amide compounds, phosphoric acid amide ester compounds, phosphinate compounds and salts thereof, ammonium phosphate, ammonium polyphosphate, melam, melam polyphosphate, melem, melem polyphosphate, red phosphorus, melon, melamine, melamine pyrophosphate, melamine cyanurate, succinoguanamine, phosphonic acid esters, phosphinic acid esters, phosphine oxide, ethylene bispentabromobenzene, and ethylene bistetrabromophthalimide.
Examples of the phosphate ester compound include triphenyl phosphate, tricresyl phosphate, xylenyl diphenyl phosphate, cresyl diphenyl phosphate, 1,3-phenylenebis(di-2,6-xylenyl phosphate), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), condensed phosphate ester compounds such as aromatic condensed phosphate ester compounds, and cyclic phosphate ester compounds.
Examples of the phosphazene compound include cyclic or chain phosphazene compounds. The cyclic phosphazene compound is also called cyclophosphazene, and is a compound having a cyclic structure and a double bond in the molecule, the double bond being composed of phosphorus and nitrogen.
Examples of the phosphite ester compound include trimethyl phosphite and triethyl phosphite.
Examples of the phosphine compound include tris-(4-methoxyphenyl)phosphine and triphenylphosphine.
These may be used alone or in combination of two or more.

The amount of other flame retardants in the resin composition of the present invention is not particularly limited, and is 0 to 200 parts by weight, preferably 0.5 to 100 parts by weight, and more preferably 1 to 50 parts by weight, per 100 parts by weight of the resin component.

[Polymerizable component]
The resin composition of the present invention may contain a polymerizable component (polymerizable monomer and/or oligomer). Examples of the polymerizable component include vinyl compounds, vinylidene compounds, diene compounds, acrylic compounds, and cyclic compounds (epoxy compounds, lactone compounds, lactam compounds, cyclic ether compounds, etc.).
Examples of these polymerization components include vinyl chloride, butadiene, isoprene, styrene, high-impact polystyrene precursors, acrylonitrile-styrene resin (AS resin) precursors, acrylonitrile-butadiene-styrene resin (ABS resin) precursors, methyl methacrylate-butadiene-styrene resin (MBS resin) precursors, methyl methacrylate-acrylonitrile-butadiene-styrene resin (MABS resin) precursors, acrylonitrile-acrylic rubber-styrene resin (AAS resin) precursors, methyl (meth)acrylate, epoxy acrylate resin precursors, epoxidized oil acrylate resin precursors, and urethane acrylate resins. Examples of the resin precursor include precursors, polyester acrylate resin precursors, polyether acrylate resin precursors, acrylic acrylate resin precursors, unsaturated polyester resin precursors, vinyl/acrylate resin precursors, vinyl ether resin precursors, polyene/thiol resin precursors, silicon acrylate resin precursors, polybutadiene acrylate resin precursors, polystyryl(ethyl)methacrylate resin precursors, polycarbonate acrylate resin precursors, alicyclic epoxy resin precursors, glycidyl ether epoxy resin precursors, and photocurable or thermosetting polyimide resin precursors, silicon-containing resin precursors, epoxy resin precursors, etc. These may be used alone or in combination of two or more.

The amount of the polymerizable component in the resin composition of the present invention is not particularly limited, and is 0 to 200 parts by weight, preferably 0.5 to 100 parts by weight, and more preferably 1 to 50 parts by weight, per 100 parts by weight of the resin component.

[Polymerization initiator]
The resin composition of the present invention may contain a polymerization initiator. The polymerization initiator can be appropriately selected depending on the method for polymerizing the resin composition of the present invention. Examples of the polymerization initiator include a thermal polymerization initiator, a photopolymerization initiator, and a radical polymerization initiator.
Examples of the thermal polymerization initiator include azo compounds such as 2,2-azobisisobutyronitrile (AIBN), 2,2-azobis(2-methylbutyronitrile), azobis-2,4-dimethylvaleronitrile, azobiscyclohexylnitrile, and azobiscyanovaleric acid; peroxides such as benzoyl peroxide, dicumyl peroxide, and diisopropyl peroxydicarbonate; and acid generators such as aromatic sulfonates. These may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include acetophenone-based photopolymerization initiators, benzophenone-based photopolymerization initiators, benzoin-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, sulfonium-based photopolymerization initiators, iodonium-based photopolymerization initiators, etc. These may be used alone or in combination of two or more kinds.
When a photopolymerization initiator is used, a sensitizer such as a tertiary amine may be used in combination, if necessary.

Examples of radical polymerization initiators include peroxides such as di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxide)hexane, 2,5-dimethyl-2,5-di(t-butylperoxide)hexyne-3, α,α'-di(t-butylperoxy)diisopropylbenzene, and t-butylperoxybenzoate. These may be used alone or in combination of two or more.

The amount of the polymerization initiator in the resin composition of the present invention is not particularly limited, and is 0 to 10 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight, per 100 parts by weight of the resin component.

[Reactive Diluent]
The resin composition of the present invention may contain a reactive diluent as necessary.
Examples of reactive diluents include aliphatic alkyl glycidyl ethers such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and allyl glycidyl ether; alkyl glycidyl esters such as glycidyl methacrylate and tertiary carboxylic acid glycidyl ester; and aromatic alkyl glycidyl ethers such as styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, p-s-butylphenyl glycidyl ether, and nonylphenyl glycidyl ether. These may be used alone or in combination of two or more.

The amount of reactive diluent in the resin composition of the present invention is not particularly limited, and is 0 to 100 parts by weight, preferably 0.1 to 50 parts by weight, and more preferably 0.1 to 20 parts by weight, per 100 parts by weight of the resin component.

[Fluororesin]
The resin composition of the present invention may contain a fluororesin for the purpose of improving the flame retardancy (particularly dripping prevention performance) of the cured product (formed product).
Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), poly(trifluorochloroethylene) (CTFE), polyfluorovinylidene (PVdF), etc. These may be used alone or in combination of two or more.

The amount of fluororesin in the resin composition of the present invention is not particularly limited, and is 0 to 20 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the resin component.

[Inorganic filler]
The resin composition of the present invention may contain an inorganic filler for the purpose of improving the flame retardancy (particularly dripping prevention performance) and mechanical strength of the cured product (formed article).
Examples of inorganic fillers include mica, natural mica, synthetic mica, kaolin, calcined kaolin, talc, calcined talc, wollastonite, silica, alumina, boron nitride, clay, calcined clay, titania, barium sulfate, barium carbonate, calcium carbonate, calcium sulfate, aluminum hydroxide, magnesium hydroxide, calcium silicate, titanium oxide, zinc oxide, zinc borate, glass beads, glass balloons, glass flakes, short glass fibers, fine glass powder, hollow glass, and fibrous aluminum titanate. Examples of the material include potassium metal salts (potassium titanate fibers, sodium titanate fibers, etc.), fibrous borates (aluminum borate fibers, magnesium borate fibers, zinc borate fibers, etc.), zinc oxide fibers, titanium oxide fibers, magnesium oxide fibers, gypsum fibers, aluminum silicate fibers, calcium silicate fibers, silicon carbide fibers, titanium carbide fibers, silicon nitride fibers, titanium nitride fibers, carbon fibers, alumina fibers, alumina-silica fibers, zirconia fibers, quartz fibers, flaky titanates, flaky titanium dioxide, etc. These may be used alone or in combination of two or more.
In particular, in order to reduce the dielectric constant of a resin composition, it is preferable to use a low dielectric constant filler such as silica, boron nitride, etc., as an inorganic filler. Examples of silica include ground silica, fused silica, natural silica, fired silica, synthetic silica, crystalline silica, and amorphous silica.
The average particle size of the inorganic filler is preferably 5 μm or less. For example, by using an inorganic filler such as silica particles having an average particle size of 5 μm or less, when the resin composition is used in a metal-clad laminate or the like, the adhesion to the metal foil is improved.
In order to suppress deterioration of the resin component, the surface of the inorganic filler may be coated with a silane coupling agent.

The amount of inorganic filler in the resin composition of the present invention is not particularly limited. In order to achieve a balance between improved flame retardancy and improved mechanical properties, the amount of inorganic filler is 0 to 200 parts by weight, preferably 5 to 100 parts by weight, per 100 parts by weight of the resin component.

[Additives]
The resin composition of the present invention may contain various additives depending on the application, the type of resin component, etc., within the range that does not impair the desired physical properties.
Examples of additives include white carbon, aluminum nitride, zinc borate, zinc stannate, zinc molybdate, molybdenum oxide, silicon nitride, aerosil, wollastonite, nanocarbons (nanocarbon tubes, graphene, fullerene, etc.), organic fibers (aramid fibers, polyparaphenylene benzobisoxazole fibers, etc.), silane coupling agents, waxes, fatty acids and metal salts thereof, release agents (acid amides, paraffin, etc.), chlorinated paraffin, silicone-based flame retardants, bromine-based flame retardants, flame retardant assistants (antimony trioxide, etc.), ultraviolet absorbers (benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, triazine compounds, etc.), antioxidants (hindered phenol compounds, styrenated phenol compounds, Examples of the additives include organic phosphorus peroxide decomposers, organic sulfur peroxide decomposers, etc.), fluorescent brighteners (stilbene derivatives, etc.), light stabilizers (hindered amine compounds, etc.), photosensitizers, gloss agents, metal deactivators (benzotriazole compounds, etc.), light shielding agents (rutile titanium oxide, zinc oxide, chromium oxide, cerium oxide, etc.), quenchers (organic nickel, etc.), curing agents, curing accelerators, crosslinking agents, diluents, flowability regulators, polymerization inhibitors, dyes, pigments, colorants, antifogging agents, antifungal agents, antibacterial agents, deodorants, plasticizers, antistatic agents, surfactants, defoamers, foaming agents, leveling agents, lubricants, lubricants, thixotropy imparting agents, thickeners, nucleating agents, reinforcing agents, compatibilizers, conductive agents, antiblocking agents, antitracking agents, luminous agents, plasticizers, adhesives, pressure sensitive adhesives, tackifiers, and various stabilizers. These may be used alone or in combination of two or more.

The amount of additives in the resin composition of the present invention is not particularly limited, and is 0 to 50 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of the resin component.

The resin composition of the present invention can be produced by mixing and/or kneading the flame retardant of the present invention and, if necessary, other flame retardants, polymerizable components, polymerization initiators, reactive diluents, fluororesins, inorganic fillers, and additives with a resin component by a known method. For example, the resin composition can be produced by mixing and/or kneading a mixture of liquid, powder, beads, flakes, or pellet-like components using an extruder (single-screw extruder, twin-screw extruder, etc.), a kneader (Banbury mixer, pressure kneader, two-roll mill, three-roll mill, etc.), etc.

(4. Thermally Radical Curable Resin Composition)
The resin composition of the present invention (hereinafter referred to as "thermal radical curable resin composition of the present invention") contains the phosphorus compound of the present invention and a thermal radical curable resin component. In addition to the phosphorus compound of the present invention and the thermal radical curable resin component, the thermal radical curable resin composition of the present invention may contain other resin components, other flame retardants, crosslinking agents, compatibilizers, radical polymerization initiators, inorganic fillers, stress relaxation agents, organic solvents, and additives as necessary. In the present invention, the resin composition means the state of the mixture before curing.

[Thermal radical curing resin component]
Examples of the thermally radically curable resin component (including resins in an uncured or semi-cured state) used in the thermally radically curable resin composition of the present invention include polyphenylene ether resins, bismaleimide resins, bismaleimide-triazine resins, polyfunctional styrene compounds, benzocyclobutene resins, polytetrafluoroethylene resins, and acrylic resins.

An example of a polyphenylene ether resin is a compound having a structure shown in formula (2).

（式中、Ｒ^ａは、同一または異なって、水素原子、炭素数１～６のアルキル基または炭素数２～６のアルケニル基を表す。ｎは、繰り返し単位の数を表し、通常、１以上の整数を表す。）

(In the formula, R ^a may be the same or different and represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms; n represents the number of repeating units and is usually an integer of 1 or more.)

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ^a include linear or branched alkyl groups having 1 to 6 carbon atoms, specifically methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-pentyl, n-hexyl, etc., of which methyl is preferred. Examples of the alkenyl group having 2 to 6 carbon atoms represented by R ^a include linear or branched alkenyl groups having 2 to 6 carbon atoms, specifically vinyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, pentenyl, hexenyl, etc. R ^a may be the same or different and is preferably a hydrogen atom or a methyl group. n is preferably 1 to 400.

Examples of compounds having the structure represented by formula (2) include compounds having the structure represented by formula (2-1), compounds having the structure represented by formula (2-2), and compounds having the structure represented by formula (2-3).

（式中、ｎは、前記と同様である。）

(In the formula, n is the same as defined above.)

（式中、ｎは、前記と同様である。）

(In the formula, n is the same as defined above.)

（式中、ｎは、前記と同様である。）

(In the formula, n is the same as defined above.)

It is preferable that the compound having the structure represented by formula (2) has two or more structures represented by formula (2) in the molecule. Furthermore, it is preferable that this compound has a crosslinkable group (for example, a group having a carbon-carbon double bond such as a (meth)acrylic group, an allyl group, or a vinylbenzyl group). It is preferable that the crosslinkable group is present at the terminal of the molecule of this compound.

A preferred embodiment of the compound having the structure represented by formula (2) is, for example, a compound represented by chemical formula (IV).

（式中、Ｘ^ａは、同一または異なって、水素原子または式（３）で示される基を表す。Ｙ^ａは、－Ｏ－または式（４）で示される基を表す。Ｒ^ａは、前記と同様である。ｎは、同一または異なって、前記と同様である。）

(In the formula, X ^a is the same or different and represents a hydrogen atom or a group represented by formula (3); Y ^a is -O- or a group represented by formula (4); ^{R a} is the same as above; n is the same or different and is the same as above.)

（式中、Ｒ^ｂ、Ｒ^ｃおよびＲ^ｄは、同一または異なって、水素原子または炭素数１～３のアルキル基を表す。Ｚは、同一または異なって、炭素数１～１０のアルキレン基、－Ｃ（＝Ｏ）－、－Ｐｈ－、－Ｐｈ－ＣＨ_２－または－Ｐｈ－ＣＨ_２ＣＨ_２－を表す。）

(In the formula, R ^b , R ^c and R ^d are the same or different and represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Z is the same or different and represents an alkylene group having 1 to 10 carbon atoms, -C(═O)-, -Ph-, -Ph-CH ₂ - or -Ph-CH ₂ CH ₂ -.)

（式中、Ｒ^ｅは、同一または異なって、水素原子、炭素数１～６のアルキル基、炭素数２～６のアルケニル基、またはアリール基を表す。Ｗは、フェニル基で置換されていてもよい炭素数１～６のアルキレン基、シクロアルキレン基、ハロゲン原子で置換されていてもよい炭素数２～６のアルケンジイル基、－Ｃ（＝Ｏ）－、－Ｓ（Ｏ）_ｍ－（ｍは、０、１または２を表す。）、または－（アルキレン）－（フェニレン）－（アルキレン）－を表す。）

(In the formula, R ^e are the same or different and represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an aryl group. W represents an alkylene group having 1 to 6 carbon atoms which may be substituted with a phenyl group, a cycloalkylene group, an alkenediyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom, -C(=O)-, -S(O) _m- (m represents 0, 1 or 2), or -(alkylene)-(phenylene)-(alkylene)-.)

Examples of the alkyl group having 1 to 3 carbon atoms represented by R ^b , R ^c and R ^d include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc. ^{R b} and R ^c are preferably a hydrogen atom, and R ^d is preferably a hydrogen atom or a methyl group.

Examples of the alkylene group having 1 to 10 carbon atoms represented by Z include a methylene group, a methylmethylene group, a dimethylene group, a trimethylene group, an ethylmethylene group, a dimethylmethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, etc. Z is preferably -C(=O)-, -Ph-, -Ph-CH ₂ - or -Ph-CH ₂ CH ₂ -.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ^e include linear or branched alkyl groups having 1 to 6 carbon atoms, specifically methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-pentyl, and n-hexyl groups. Examples of the alkenyl group having 2 to 6 carbon atoms represented by R ^e include linear or branched alkenyl groups having 2 to 6 carbon atoms, specifically vinyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, pentenyl, and hexenyl groups. Examples of the aryl group represented by R ^e include phenyl, 2-tolyl, 3-tolyl, and 4-tolyl groups. R ^e is preferably a hydrogen atom or a methyl group.

Examples of alkylene groups having 1 to 6 carbon atoms which may be substituted with a phenyl group represented by W include, for example, a methylene group, a methylmethylene group, a dimethylmethylene group, a phenylmethylene group, a phenylmethylmethylene group, and a diphenylmethylene group. Examples of cycloalkylene groups represented by W include, for example, a cyclohexane-1,1-diyl group. Examples of alkene diyl groups having 2 to 6 carbon atoms which may be substituted with a halogen atom represented by W include, for example, ethylene-1,1-diyl and 2,2-dichloroethylene-1,1-diyl. Examples of -(alkylene)-(phenylene)-(alkylene)- represented by W include, for example, -(alkylene having 1 to 3 carbon atoms)-(phenylene)-(alkylene having 1 to 3 carbon atoms)-. Examples of alkylene groups having 1 to 3 carbon atoms include methylene, methylmethylene, dimethylene, trimethylene, ethylmethylene, and dimethylmethylene groups, and are preferably dimethylmethylene groups. Examples of phenylene groups include 1,2-phenylene, 1,3-phenylene, and 1,4-phenylene groups, and are preferably 1,4-phenylene groups. W is preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms (particularly a dimethylmethylene group).

Y ^a is preferably a group represented by formula (4) (wherein R ^e represents a hydrogen atom or a methyl group, and W represents an alkylene group having 1 to 3 carbon atoms).

Preferred examples of the compounds represented by chemical formula (IV) include compounds represented by chemical formula (IV-1), compounds represented by chemical formula (IV-2), and compounds represented by chemical formula (IV-3).

（式中、Ｒ^ａ、Ｒ^ｄ、Ｗおよびｎは、前記と同様である。）

(In the formula, R ^a , R ^d , W and n are the same as defined above.)

（式中、Ｒ^ａ、Ｒ^ｂ、Ｒ^ｃ、Ｒ^ｄ、Ｗおよびｎは、前記と同様である。）

(In the formula, R ^a , R ^b , R ^c , R ^d , W and n are the same as defined above.)

（式中、ｎは、前記と同様である。）

(In the formula, n is the same as defined above.)

These polyphenylene ether resins can be synthesized according to or in accordance with known methods, such as those described in U.S. Pat. No. 4,059,568 and The Journal of Organic Chemistry, 34, 297-303 (1969).

The weight average molecular weight (Mw) of the polyphenylene ether resin is usually 1,000 to 120,000, preferably 1,000 to 50,000, and more preferably 1,000 to 20,000. The weight average molecular weight can be measured using gel permeation chromatography (GPC) in styrene equivalent.

Bismaleimide resin is a compound having two maleimide groups in the molecule, and refers to a bismaleimide compound before curing. Examples of bismaleimide resins include aliphatic bismaleimide compounds and aromatic bismaleimide compounds.

Examples of aliphatic bismaleimide compounds include N,N'-(2,2,4-trimethylhexamethylene)bismaleimide, N,N'-decamethylene bismaleimide, N,N'-octamethylene bismaleimide, N,N'-heptamethylene bismaleimide, N,N'-hexamethylene bismaleimide, N,N'-pentamethylene bismaleimide, N,N'-tetramethylene bismaleimide, N,N'-trimethylene bismaleimide, N,N'-ethylene bismaleimide, N,N'-(oxydimethylene)bismaleimide, 1,13-bismaleimide-4,7,10-trioxatridecane, and 1,11-bismaleimide-3,6,9-trioxaundecane.

Examples of aromatic bismaleimide compounds include N,N'-(4-methyl-1,3-phenylene)bismaleimide, N,N'-(1,3-phenylene)bismaleimide, N,N'-(1,4-phenylene)bismaleimide, N,N'-(1,2-phenylene)bismaleimide, N,N'-(1,5-naphthylene)bismaleimide, N,N'-(4-chloro-1,3-phenylene)bismaleimide, and N,N'-(methylenedi-p-phenylene)bismaleimide. bismaleimide, N,N'-(4,4'-biphenylene)bismaleimide, N,N'-(sulfonyldi-p-phenylene)bismaleimide, N,N'-(oxydi-p-phenylene)bismaleimide, N,N'-(3,3'-dimethyl-4,4'-biphenylene)bismaleimide, N,N'-(benzylidene di-p-phenylene)bismaleimide, N,N'-[methylenebis(3-chloro-4-phenylene)]bismaleimide, N,N'-[methylene bis(3-methyl-4-phenylene)]bismaleimide, N,N'-[methylenebis(3-methoxy-4-phenylene)]bismaleimide, N,N'-(thiodi-p-phenylene)bismaleimide, N,N'-3,3'-benzophenone bismaleimide, N,N'-[methylenebis(3-methyl-5-ethyl-4-phenylene)]bismaleimide, N,N'-[tetramethylenebis(oxy-p-phenylene)]bismaleimide, 2,2-bis[4 -(4-maleimidophenoxy)phenyl]propane, bis[4-(4-maleimidophenoxy)phenyl]sulfone, 1,4-phenylenebis(4-maleimidophenoxy), bis[3-(4-maleimidophenoxy)phenyl]sulfone, bis[4-(3-maleimidophenoxy)phenyl]ketone, 1,3-phenylenebis(4-maleimidophenoxy), bis[4-(4-maleimidophenylthio)phenyl]ether, etc. These may be used alone or in combination of two or more.

There are no particular limitations on the bismaleimide-triazine resin, so long as it is a prepolymer made mainly of a maleimide compound and a cyanate ester compound. For example, there is one in which 2,2-bis(4-cyanatophenyl)propane and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane are heated and melted to polymerize, and one in which novolac-type cyanate ester resin and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane are heated and melted to polymerize, and then dissolved in methyl ethyl ketone.

Examples of polyfunctional styrene compounds include bisvinylphenylmethane, 1,2-bis(m-vinylphenyl)ethane, 1,2-bis(p-vinylphenyl)ethane, 1-(p-vinylphenyl)-2-(m-vinylphenyl)ethane, 1,3-bis(m-vinylphenylethyl)benzene, 1,3-bis(p-vinylphenylethyl)benzene, 1-(p-vinylphenylethyl)-3-(m-vinylphenylethyl)benzene, 1,4-bis(m-vinylphenylethyl)benzene, 1,4-bis(p-vinylphenylethyl)benzene, 1,6-bis(vinylphenyl)hexane, and divinylbenzene polymers (oligomers) having vinyl groups on the side chains.

There are no particular limitations on the benzocyclobutene resin, so long as it has two or more benzocyclobutene groups bonded directly or via an organic group.

In the thermally radically curable resin composition of the present invention, the above-mentioned thermally radically curable resin components may be used alone or in combination of two or more kinds.

[Other resin components]
In the thermal radical curable resin composition of the present invention, in addition to the thermal radical curable resin component, if necessary, a resin component other than the thermal radical curable resin component (other resin component) may be used in combination. Examples of the other resin components include the above-mentioned resin components (resin components described in paragraph [0056]), styrene-based block copolymers, etc. Examples of the styrene-based block copolymers include styrene-butadiene block copolymers, styrene-isoprene block copolymers, styrene-ethylene/butylene-styrene block copolymers (SEBS), styrene-(ethylene-ethylene/propylene)-styrene block copolymers (SEEPS), styrene-ethylene/propylene-styrene block copolymers (SEPS), etc. These may be used alone or in combination of two or more.

The amount of other resin components in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0 to 1,000 parts by weight, preferably 50 to 800 parts by weight, and more preferably 100 to 700 parts by weight, per 100 parts by weight of the thermally radically curable resin component.

[Flame retardant]
In the thermally radically curable resin composition of the present invention, in addition to the phosphorus compound of the present invention as a flame retardant, a flame retardant other than the phosphorus compound of the present invention (other flame retardants described in paragraph [0058]) may be used in combination as necessary.

The amount of the phosphorus compound of the present invention in the thermally radically curable resin composition of the present invention is not particularly limited, and is 1 to 200 parts by weight, preferably 1 to 160 parts by weight, and more preferably 2 to 100 parts by weight, per 100 parts by weight of the resin components (the total of the thermally radically curable resin component and other resin components).
The amount of the other flame retardant in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0 to 100 parts by weight, preferably 1 to 80 parts by weight, and more preferably 1 to 40 parts by weight, relative to 100 parts by weight of the resin component (the total of the thermally radically curable resin component and the other resin component).

[Crosslinking agent]
The thermal radical curable resin composition of the present invention may contain a crosslinking agent within a range in which the effect of the resin composition can be exhibited. Examples of crosslinking agents include monobenzyl diallyl isocyanurate such as mono(alkyl having 6 to 20 carbon atoms), 1-benzyl-3,5-diallyl isocyanurate, and 1-(4-vinylbenzyl)-3,5-diallyl isocyanurate, triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl trimellitate, and polyfunctional styrene compounds (polyfunctional styrene compounds described in paragraph [0104]). These may be used alone or in combination of two or more.

The amount of the crosslinking agent in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0 to 200 parts by weight, preferably 5 to 150 parts by weight, and more preferably 10 to 100 parts by weight, per 100 parts by mass of the resin components (total of the thermally radically curable resin components and other resin components).

The thermally radically curable resin composition of the present invention may further contain other components as necessary, such as a compatibilizer, a radical polymerization initiator (the radical polymerization initiator described in paragraph [0064]), an inorganic filler (the inorganic filler described in paragraph [0070]), a stress relaxation agent, an organic solvent, an additive (the additive described in paragraph [0072]), etc.

[Compatibilizer] Examples of compatibilizers include 1,2-polybutadiene, 1,4-polybutadiene, maleic acid-modified polybutadiene, acrylic-modified polybutadiene, and epoxy-modified polybutadiene. These may be used alone or in combination of two or more.

The amount of the compatibilizer in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0 to 100 parts by weight, preferably 20 to 50 parts by weight, per 100 parts by mass of the resin components (total of the thermally radically curable resin components and other resin components).

[Radical polymerization initiator] The amount of radical polymerization initiator in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0.001 to 10 parts by weight, preferably 0.005 to 5 parts by weight, and more preferably 0.01 to 3 parts by weight, per 100 parts by weight of the resin components (total of the thermally radically curable resin components and other resin components).

[Inorganic filler] The amount of inorganic filler in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0 to 500 parts by weight, preferably 1 to 200 parts by weight, and more preferably 5 to 100 parts by weight, per 100 parts by weight of the resin components (total of the thermally radically curable resin components and other resin components).

[Stress relaxation agent] The stress relaxation agent is not particularly limited, and examples thereof include silicone resin particles. The average particle size of the stress relaxation agent is preferably 10 μm or less. By using a stress relaxation agent having such an average particle size, adhesion to metal foil is improved when the thermo-radical curable resin composition of the present invention is used in a metal-clad laminate or the like.

The amount of the stress relaxation agent in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0 to 100 parts by weight, preferably 0 to 50 parts by weight, per 100 parts by mass of the resin components (total of the thermally radically curable resin components and other resin components).

[Organic solvent] The organic solvent is not particularly limited as long as it can dissolve or disperse the thermally radically curable resin component, and examples thereof include ketone solvents such as methyl ethyl ketone (MEK); ether solvents such as dibutyl ether; ester solvents such as ethyl acetate; amide solvents such as dimethylformamide; aromatic hydrocarbon solvents such as benzene, toluene, xylene; and chlorinated hydrocarbon solvents such as trichloroethylene. These may be used alone or in combination of two or more. The thermally radically curable resin composition of the present invention containing an organic solvent can be used to produce a prepreg by impregnating a substrate as a resin varnish, as described below.

The amount of organic solvent in the thermally radically curable resin composition of the present invention can be adjusted according to the operation of applying or impregnating/applying the resin varnish to a substrate, and is 30 to 1,000 parts by weight, preferably 100 to 500 parts by weight, per 100 parts by mass of the resin components (total of the thermally radically curable resin components and other resin components).

[Additives] The amount of additives in the thermally radically curable resin composition of the present invention is not particularly limited, and is 0 to 50 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of the resin components (total of the thermally radically curable resin components and other resin components).

The thermally radically curable resin composition of the present invention can be produced by mixing and/or kneading the thermally radically curable resin component with the flame retardant of the present invention and, if necessary, other resin components, other flame retardants, crosslinking agents, compatibilizers, radical polymerization initiators, inorganic fillers, stress relaxation agents, organic solvents, and additives by known methods. For example, the composition can be produced by mixing and/or kneading a mixture of liquid, powder, beads, flakes, or pellet-like components using an extruder (single-screw extruder, twin-screw extruder, etc.), kneader (Banbury mixer, pressure kneader, two-roll, three-roll, etc.), etc.

(5. Uses of the Resin Composition of the Present Invention)
The resin composition described in the above 3. and the heat-radical curable resin composition described in the above 4. (hereinafter, both are collectively referred to as "the resin composition of the present invention") can be suitably used for applications such as prepregs, resin-coated metal foils, thermosetting resin films, metal-clad laminates, printed wiring boards, resin boards, semiconductor devices, and adhesives.

[Prepreg]
The prepreg of the present invention will be described.
When the resin composition of the present invention is used to produce a prepreg for use in RCC, etc., the resin composition of the present invention can be prepared in a varnish form and used as a resin varnish. Such a resin varnish can be prepared, for example, as follows.
First, each component that can be dissolved in an organic solvent (each component contained in the resin composition of the present invention) is put into an organic solvent and dissolved. At this time, heating may be performed as necessary. Then, a component that cannot be dissolved in an organic solvent (each component contained in the resin composition of the present invention) is added as necessary, for example, an inorganic filler, and dispersed until a predetermined dispersion state is reached using a ball mill, a bead mill, a planetary mixer, a roll mill, or the like, to prepare a varnish-like resin composition of the present invention.

The prepreg of the present invention comprises the resin composition of the present invention or a semi-cured product of the resin composition of the present invention, and a substrate. The semi-cured product is the resin composition of the present invention in a partially cured state (B-staged state).

The prepreg of the present invention may be a prepreg comprising a semi-cured product of the resin composition of the present invention (a resin composition in a B-stage state) and a substrate, or a prepreg comprising a resin composition of the present invention before curing (a resin composition in an A-stage state) and a substrate.

Examples of substrates used in prepregs include glass cloth, aramid cloth, polyester cloth, LCP (liquid crystal polymer) nonwoven fabric, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. Examples of glass cloth materials include normal E-glass, as well as D-glass, S-glass, NE-glass, quartz glass, and L-glass. When glass cloth is used, a laminate with excellent mechanical strength is obtained. As the glass cloth, glass cloth that has been flattened is preferable. Flattening can be performed, for example, by continuously pressing the glass cloth with a press roll at an appropriate pressure to compress the yarns flat. Examples of the thickness of the substrate include 0.02 to 0.3 mm.

The proportion of the base material in the prepreg is 20 to 80% by weight of the entire prepreg, and preferably 25 to 70% by weight.

Examples of methods for producing prepregs include a method in which the resin composition of the present invention is prepared in a varnish form and then impregnated or coated on a substrate. Examples of methods for impregnation and coating include a method in which the substrate is immersed (dipping), a method in which coating is performed using a roll, die coat, bar coat, or the like, and a method in which the substrate is sprayed with a sprayer, etc. This impregnation and coating can be repeated multiple times as necessary. It is also possible to repeat impregnation and coating using multiple resin compositions with different resin component concentrations. After impregnation and coating, the substrate may be dried or heated.

The substrate impregnated and coated with the resin composition of the present invention is heated at 80 to 180°C for 1 to 10 minutes to obtain a prepreg in a semi-cured state (B-stage state).

Table 1 shows a preferred blend example (excluding organic solvents) when using the resin composition of the present invention in a prepreg.

By using such prepregs, it is possible to manufacture metal-clad laminates and printed wiring boards that have excellent electrical properties (e.g., dielectric properties), heat resistance, flame retardancy, adhesive strength, and chemical resistance.

[Metal foil with resin]
The resin-coated metal foil of the present invention will be described.
The resin-coated metal foil of the present invention comprises a resin layer containing the resin composition of the present invention or a semi-cured product of the resin composition of the present invention, and a metal foil.
The resin-coated metal foil of the present invention comprises a metal foil on the surface of a resin layer containing the resin composition of the present invention or a semi-cured product of the resin composition of the present invention. The resin-coated metal foil of the present invention may also comprise another layer between the resin layer and the metal foil.

As described above, the resin layer may be a semi-cured product of the resin composition of the present invention (a resin composition in a B-stage state) or the resin composition of the present invention before curing (a resin composition in an A-stage state). The resin layer may or may not contain a substrate. The substrate may be the same as the substrate of the prepreg.

Examples of metal foil include copper foil and aluminum foil. The thickness of the copper foil is about 12 to 70 μm.

The method for producing the resin-coated metal foil of the present invention can be, for example, a method in which the resin composition of the present invention prepared in a varnish form as described above is applied onto a metal foil. The application method is not particularly limited as long as it is a method that can apply the resin composition of the present invention to the metal foil. Examples include a method of application using a roll, die coater, bar coater, etc., and a method of spraying using a sprayer, etc. After application, the composition may be dried or heated.

The metal foil coated with the resin composition of the present invention can be heated at 80 to 180°C for 1 to 10 minutes to obtain a resin-coated metal foil in a semi-cured state (B-stage state).

Preferable blending examples (excluding organic solvents) when the resin composition of the present invention is used for a resin-coated metal foil containing a substrate are the same as those for the prepreg described above (see Table 1 in paragraph [0133]). In addition, preferred blending examples (excluding organic solvents) when the resin composition of the present invention is used for a resin-coated metal foil not containing a substrate are shown in Table 2.

By using such resin-coated metal foil, it is possible to manufacture metal-clad laminates and printed wiring boards that have excellent electrical properties (e.g., dielectric properties), heat resistance, flame retardancy, adhesive strength, and chemical resistance.

[Thermosetting resin film]
The thermosetting resin film of the present invention will be described.
The thermosetting resin film of the present invention can be produced by forming the resin composition of the present invention into a desired shape. For example, the thermosetting resin film of the present invention can be produced by applying the resin composition of the present invention onto a support and then drying it.
The support is not particularly limited, and examples thereof include metal foils such as copper and aluminum, and organic films such as polyester resin, polyethylene resin, and polyethylene terephthalate resin (PET). The support may be subjected to a release treatment with a silicone compound or the like. The resin composition of the present invention can be used in various shapes, and the shape is not particularly limited.

The method for applying the resin composition of the present invention to a support is not particularly limited, but from the viewpoint of thinning and controlling the film thickness, the gravure method, slot die method, doctor blade method, etc. are preferred. With the slot die method, it is possible to obtain an uncured film of the resin composition (thermosetting resin film of the present invention) that has a thickness of 5 to 300 μm after heat curing.

Drying conditions can be set appropriately depending on the type and amount of organic solvent used in the resin composition of the present invention, the thickness of the coating, etc. For example, drying conditions can be set to 50 to 120°C and 1 to 60 minutes. The thermosetting resin film of the present invention obtained in this manner has good storage stability. The thermosetting resin film can be peeled off from the support at the desired time.

The thermosetting resin film of the present invention can be cured, for example, at 150 to 230° C. for 30 to 180 minutes. The thermosetting resin film of the present invention may be cured after sandwiching the thermosetting resin film between substrates on which wiring made of copper foil or the like is formed, or after appropriately laminating the thermosetting resin film on which wiring made of copper foil or the like is formed. The thermosetting resin film can also be used as a coverlay film for protecting wiring on a substrate, and the curing conditions in this case are also the same.
The thermosetting resin film of the present invention can also be suitably used for flexible copper clad laminates (FCCLs) for flexible printed circuit boards (FPCs), copper clad laminates (CCLs) for multilayer boards, build-up materials, and the like.

Table 3 shows a preferred blend example (excluding organic solvents) when using the resin composition of the present invention in a thermosetting resin film. When adding an organic solvent, it is preferable to add it appropriately so that the viscosity is in the range of 200 to 3000 mPa·s.

[Metal-clad laminate]
The metal-clad laminate of the present invention will now be described.
The metal-clad laminate of the present invention comprises an insulating layer containing a cured product of the resin composition of the present invention and a metal foil. The metal-clad laminate comprises the metal foil on the surface of the insulating layer. The metal-clad laminate may also comprise another layer between the insulating layer and the metal foil.
The insulating layer may or may not include a base material. The base material may be the same as the base material of the prepreg. The metal foil may be the same as the metal foil of the resin-coated metal foil.

Examples of the method for producing a metal-clad laminate include a method using the above-mentioned prepreg. Examples of the method for producing a metal-clad laminate using a prepreg include a method in which one or more prepregs are stacked, and a metal foil such as copper foil is stacked on both sides or one side of the prepreg, and the stack is heated and pressurized to laminate and integrate the stack. By this method, a laminate with metal foil on both sides or one side can be produced.
The heating and pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate to be produced, the composition of the resin composition used in the prepreg, etc. For example, the conditions can be: temperature: 170 to 220° C., pressure: 1.5 to 5.0 MPa, and time: 60 to 150 minutes.
The metal-clad laminate can also be produced without using a prepreg, for example, by applying the resin composition of the present invention in a varnish form onto a metal foil, forming a layer containing the resin composition of the present invention on the metal foil, and then applying heat and pressure to the metal foil, or by curing a thermosetting resin film using a metal foil as a support.

Preferable compounding examples (excluding organic solvents) when the resin composition of the present invention is used in a metal-clad laminate containing a substrate are the same as those in the prepreg described above (see Table 1 in paragraph [0133]). In addition, preferable compounding examples (excluding organic solvents) when the resin composition of the present invention is used in a metal-clad laminate not containing a substrate are the same as those in the resin-attached metal foil not containing a substrate described above (see Table 2 in paragraph [0141]).

By using such metal-clad laminates, it is possible to manufacture printed wiring boards with excellent electrical properties (e.g., dielectric properties, etc.), heat resistance, flame retardancy, adhesive strength, and chemical resistance.

[Printed wiring board]
The printed wiring board of the present invention will now be described.
The printed wiring board of the present invention comprises an insulating layer containing a cured product of the resin composition of the present invention or a cured product of the thermosetting film of the present invention, and wiring. The printed wiring board of the present invention comprises wiring on the surface of the insulating layer. The printed wiring board of the present invention may also comprise another layer between the insulating layer and the wiring.
The insulating layer may or may not contain a base material. The base material may be the same as that of the prepreg.
The printed wiring board of the present invention has an insulating layer containing a cured product of the resin composition of the present invention or a cured product of the thermosetting resin film of the present invention, and thus has excellent electrical properties (e.g., dielectric properties, etc.) and high flame retardancy.

The wiring is not particularly limited as long as it is wiring that can be provided on a printed wiring board. For example, wiring formed by partially removing metal foil laminated on an insulating layer can be used. In addition, wiring formed by methods such as subtractive, additive, semi-additive, chemical mechanical polishing (CMP), trench, inkjet, squeegee, and transfer can be used.

Examples of methods for manufacturing printed wiring boards include a method using the above-mentioned metal-clad laminate. Examples of methods for manufacturing printed wiring boards using metal-clad laminates include a method in which the metal foil on the surface of the metal-clad laminate is etched to form a circuit. This method makes it possible to obtain a printed wiring board in which a conductor pattern is provided as a circuit on the surface of the metal-clad laminate.

Preferable compounding examples (excluding organic solvents) when the resin composition of the present invention is used in a printed wiring board containing a substrate in the insulating layer are the same as those in the prepreg described above (see Table 1 in paragraph [0133]). In addition, preferable compounding examples (excluding organic solvents) when the resin composition of the present invention is used in a printed wiring board not containing a substrate in the insulating layer are the same as those in the resin-coated copper foil not containing a substrate described above (see Table 2 in paragraph [0141]).

The printed wiring board obtained in this manner has excellent electrical properties (e.g., dielectric properties, etc.), heat resistance, flame retardancy, and chemical resistance, and the delamination of the circuit is sufficiently suppressed. Furthermore, even when it is in the form of a package to which a semiconductor chip is bonded, it is easy to mount, has no variation in quality, and has excellent signal speed and impedance.

[Resin plate]
The resin composition of the present invention can also be used as a resin plate cured into a plate shape. For example, a resin plate obtained by applying the resin composition of the present invention in a varnish form to a plate shape, drying, and then curing can be used. In addition, the resin plate can also be an unclad plate obtained by removing the metal foil from the metal-clad laminate.

[Semiconductor device]
The case where the resin composition of the present invention is used in a semiconductor device will be described.
A semiconductor device can be manufactured by using and curing the resin composition of the present invention or the thermosetting resin film of the present invention. This semiconductor device is suitable for high frequency applications because it has excellent electrical properties (e.g., dielectric properties, etc.) and high flame retardancy due to the cured product of the resin composition of the present invention or the cured product of the thermosetting resin film of the present invention.
The term "semiconductor device" refers to any device that can function by utilizing semiconductor characteristics, and includes electronic components, semiconductor circuits, modules incorporating these, electronic equipment, and the like.

[glue]
The adhesive of the present invention will now be described.
The adhesive of the present invention contains the resin composition of the present invention as a component. The adhesive of the present invention can be used as an adhesive between two materials selected from metals, inorganic materials, and resin materials. In particular, the adhesive is preferably used as an adhesive between a metal and a material selected from metals, inorganic materials, and resin materials.

Examples of the metals include copper, aluminum, titanium, nickel, tin, iron, silver, gold, and alloys thereof. Of these metals, copper is preferred. Examples of the metal form include plates, foils, plated films, etc. made of these metals.

Examples of the inorganic material include silicon, ceramics, carbon used as a filler, inorganic salts, glass, etc. Specific examples include silicon compounds such as silicon, silicon carbide, silica, glass, diatomaceous earth, calcium silicate, talc, glass beads, sericite activated clay, bentonite, aluminosilicate, and mica; oxides such as alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, and titanium oxide; hydroxides such as magnesium hydroxide, aluminum hydroxide, and basic magnesium carbonate; carbonates such as calcium carbonate, zinc carbonate, hydrotalcite, and magnesium carbonate; sulfates such as barium sulfate and gypsum; titanates such as barium titanate; nitrides such as aluminum nitride and silicon nitride; graphites such as flake graphite (natural graphite), expanded graphite, and expanded graphite (synthetic graphite); activated carbons; carbon fibers; and carbon black.
Among these inorganic materials, silicon, ceramics (alumina, silicon carbide, aluminum nitride, silicon nitride, barium titanate, etc.), glass and inorganic salts are preferred.

Examples of the resin material include nylon, acrylate resin, epoxy resin, olefin resin, benzoxazine resin, polybenzoxazole resin, silicone resin, polyamide resin, polyimide resin, bismaleimide resin, maleimide resin, cyanate resin, polyphenylene ether resin, polyphenylene oxide resin, fluorine-containing resin, polyether resin, polyetherimide resin, polyether ether ketone resin, polyester resin, silicone resin, liquid crystal resin, and the like. These may be mixed or modified together to form a combination.
Among these resin materials, acrylate resin, epoxy resin, olefin resin, benzoxazine resin, polybenzoxazole resin, bismaleimide resin, polyphenylene ether resin, fluorine-containing resin, polyether resin, liquid crystal resin, silicone resin and polyimide resin are preferable.

Methods for bonding materials using adhesives can be carried out by known methods. Specifically, there are (1) a method in which an adhesive is applied to the surface of a material selected from metals, inorganic materials, and resin materials, and another material is pressed onto part or all of the applied adhesive to bond (cure), and (2) a method in which a sheet of semi-cured adhesive is attached to the surface of a material selected from metals, inorganic materials, and resin materials, and another material is pressed onto part or all of the other side of the adhesive to bond (cure).

The adhesive can be cured by a known method. For example, it can be heated and pressed using a heat press, or it can be heat-treated after drying the adhesive that has been applied first. Heating and pressing conditions can be, for example, temperature: 50 to 300°C (particularly, 80 to 250°C), pressure: 0.1 to 50 MPa (particularly, 0.5 to 10 MPa), time: about 1 minute to 10 hours (particularly, about 30 minutes to 5 hours).

The adhesive of the present invention can be used to bond two materials, particularly two materials made of different materials, and can therefore be suitably used in various electrical or electronic components, semiconductor wafers, printed wiring boards, flexible metal-clad laminates, and other electronic devices.

Preferred formulation examples (excluding organic solvents) for using the resin composition of the present invention as an adhesive are the same as those for the thermosetting resin film described above (see Table 3 in paragraph [0148]).

In this specification, the terms "comprise" and "have" include the concepts of "consisting essentially of" and "consisting of."

The present invention will be described in more detail below with reference to Examples (synthesis test, evaluation test) and Comparative Examples (evaluation test), but the present invention is not limited thereto. "Parts" used herein means "parts by weight" unless otherwise specified.
The main raw materials used in the reference examples and synthesis tests are as follows.

[Main raw materials]
2-Phenoxy-5,5-bis(bromomethyl)-1,3,2-dioxaphosphorinane 2-oxide (synthesized according to the method described in Indian Journal of Chemistry, Section B: Organic Chemistry Including Medicinal Chemistry, 44B(6), 1248-1251(2005). See chemical formula (II-1-1).)
Diallyl isocyanurate (manufactured by Shikoku Chemical Industry Co., Ltd.; see chemical formula (III-1))
・N,N-Dimethylformamide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
・Potassium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
・Potassium iodide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
- Isopropyl alcohol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
・4-(Methanesulfonyloxy)methyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide (synthesized according to the method described in RSC Advances, 6(57), 52485-52494(2016). See chemical formula (II-2-1).)
・Sodium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
・Sodium iodide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

The main raw materials (excluding the phosphorus compound of the present invention) used in the evaluation tests are as follows.
[Main raw materials]
(A) Flame retardant: 1,3-phenylenebis(di-2,6-xylenyl phosphate) (manufactured by Daihachi Chemical Industry Co., Ltd., product name "PX-200", see chemical formula (V)).

(B) Thermally radically curable resin component - methacrylic modified polyphenylene ether (manufactured by SABIC, polyphenylene ether resin, product name "SA9000-111", molecular weight: 2300)
(C) Other resin components: Styrene-butadiene block copolymer (manufactured by Asahi Kasei, styrene-based block copolymer, product name "Tufprene A", styrene/butadiene weight ratio = 40/60)
(D) Crosslinking agent: 1-dodecyl-3,5-diallyl isocyanurate (manufactured by Shikoku Chemical Industry Co., Ltd.)
(E) Radical polymerization initiator: α,α'-di(t-butylperoxy)diisopropylbenzene (manufactured by NOF Corp., trade name "Perbutyl P")
(F) Inorganic filler - silica (manufactured by Admatechs, product name "Admafine SC2300-SVJ")
(G) Organic solvent - toluene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

The methods of evaluation tests (flame retardancy evaluation, Tg and CTE measurement, and adhesion evaluation) used in the examples and comparative examples are as follows:

[Flame retardancy evaluation]
The resin composition was applied to a 25 μm-thick polyimide film using a bar coater so that the coating film after drying had a thickness of 50±5 μm, and toluene was distilled off until a constant weight was reached. Then, a film for evaluation was produced by performing a heat treatment under conditions of 150° C. for 30 minutes and 200° C. for 1 hour. The flame retardancy of this film for evaluation was evaluated according to the UL94 VTM test method of the vertical flame test of the US UL standard.

[Measurement of Tg and CTE]
The resin composition was poured into an aluminum cup with a radius of 3.5 cm coated with a mold release agent so that the thickness after curing would be 1.5 mm, and toluene was distilled off until a constant weight was reached. A cured product for evaluation was then produced by heat treating the product at 150°C for 30 minutes and at 200°C for 1 hour. The glass transition temperature (Tg) and coefficient of linear expansion (CTE) of the cured product for evaluation were measured using a thermomechanical analyzer (TMA, Hitachi High-Tech Science, "TMA7100") (flow gas: nitrogen, heating condition: 5°C/min.).

[Evaluation of Adhesion]
The resin composition was applied to a 10 x 10 cm polyimide film (thickness: 40 μm, Toray DuPont, "Kapton LK") so that the thickness after drying would be 15 μm, and toluene was distilled off until a constant weight was reached. A glass epoxy substrate (FR-4 grade) was then placed on the surface coated with the resin composition, and pressed under heating and pressure conditions of 150°C for 30 minutes and 200°C for 1 hour at 0.5 MPa to prepare a test specimen. The normal peel strength of this test specimen was measured in accordance with "JIS C6481".

Example 1
<Synthesis of 2-phenoxy-5,5-bis[(tetrahydro-2,4,6-trioxo-3,5-di-2-penten-1-yl-1,3,5-triazin-1(2H)-yl)methyl]-1,3,2-dioxaphosphorinane 2-oxide>
A 1 L recovery flask was charged with 40.00 g (100.00 mmol) of 2-phenoxy-5,5-bis(bromomethyl)-1,3,2-dioxaphosphorinane 2-oxide, 46.02 g (220.00 mmol), diallyl isocyanurate, 34.55 g (250.00 mmol), potassium carbonate, 1.66 g (10.00 mmol) of potassium iodide, and 200.00 g of dimethylformamide, and the mixture was heated to 100° C. with stirring and continued to be stirred for 36 hours.
Toluene was then added to the reaction solution, which was then washed with water, and the organic layer was concentrated. The resulting concentrate was recrystallized from isopropyl alcohol to obtain 41.50 g of a white powder (yield 63.2%).

^{The 1} H-NMR spectrum data of this white powder was as follows:
・¹ H-NMR (d ₆ -DMSO) δ: 7.42(t, 2H), 7.24(t, 1H), 7.21(d, 2H), 5.76-5.85(m, 4H), 5.11-5.27(m, 8H), 4.86(s, 2H), 4.35-4.48(m, 12H), 4.26(s, 2H).
The IR spectrum data of this white powder was as shown in the chart of FIG.
From these spectral data, the obtained white powder was identified as the title phosphorus compound represented by chemical formula (I-1-1).

Example 2
<Synthesis of 4-(tetrahydro-2,4,6-trioxo-3,5-di-2-penten-1-yl-1,3,5-triazin-1(2H)-yl)methyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide>
In a 1L eggplant flask, 41.31g (160.00mmol) of 4-(methanesulfonyloxy)methyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide, 35.15g (168.00mmol), diallyl isocyanurate, 25.43g (240.00mmol), sodium carbonate, 2.40g (16.00mmol), and N,N-dimethylformamide, 188.80g, were charged and heated to 100°C while stirring, and stirred for 14 hours. After cooling to 30°C, 400g of water was added, and the precipitated solid was filtered off. The solid was washed with a saturated aqueous solution of sodium bicarbonate, water, and methanol, and dried under reduced pressure to obtain 45.00g of white powder (yield 75.80%).

^{The 1} H-NMR spectrum data of this white powder was as follows:
・^1H -NMR (d ₆ -DMSO) δ: 5.77-5.86(m, 2H), 5.13-5.29(m, 4H), 4.67(d, 6H), 4.33-4.35(m, 4H), 3.73(s, 2H).
The IR spectrum data of this white powder was as shown in the chart of FIG.
From these spectral data, the obtained white powder was identified as the title phosphorus compound represented by chemical formula (I-2-1).

Example 3
A thermal radical curable resin composition was prepared by mixing 107.5 parts by weight of the phosphorus compound synthesized in Example 1 as a flame retardant, 22.4 parts by weight of methacrylic modified polyphenylene ether as a thermal radical curable resin component, 138.8 parts by weight of a styrene-butadiene block copolymer as another resin component, 20.0 parts by weight of 1-dodecyl-3,5-diallyl isocyanurate as a crosslinking agent, 1.2 parts by weight of α,α'-di(t-butylperoxy)diisopropylbenzene as a radical polymerization initiator, 134.4 parts by weight of silica as an inorganic filler, and 314.8 parts by weight of toluene as an organic solvent.
This resin composition was subjected to evaluation tests, and the test results obtained are shown in Table 4.

[Example 4, Comparative Examples 1 and 2]
In the same manner as in Example 3, thermally curable resin compositions having the compositions shown in Table 4 were prepared and evaluation tests were carried out on these resin compositions. The test results obtained were as shown in Table 4.

As seen from the results in Table 4, both Examples 3 and 4, in which the phosphorus compound of the present invention having an isocyanurate ring and an unsaturated bond group (allyl group) in the molecule was used as a flame retardant, showed improved flame retardancy compared to Comparative Example 1, in which no flame retardant was used, and showed flame retardancy equivalent to that of Comparative Example 2, in which a conventional flame retardant was used.
Moreover, both Examples 3 and 4 exhibited higher Tg and lower CTE values than Comparative Examples 1 and 2. This indicates that the crosslink density of the cured products of the resin compositions of Examples 3 and 4 was increased, the heat resistance was high, and the volume change due to temperature was suppressed.
In addition, in both Examples 3 and 4, the adhesion is improved compared to Comparative Example 1.
Therefore, it can be seen that the use of the phosphorus compounds of the present invention (the compounds of Examples 1 and 2) as flame retardants gives cured products having low thermal expansion properties, heat resistance, adhesive properties (adhesion) and excellent flame retardancy.

The phosphorus compound of the present invention is expected to be used as a flame retardant for resins.
In addition, the resin composition containing the phosphorus compound of the present invention is expected to give a cured product having excellent low thermal expansion properties, heat resistance, adhesiveness (adhesion), mechanical properties, electrical properties and flame retardancy, and is therefore suitable as a material for printed wiring boards, adhesive materials, etc.

Claims (11)

A phosphorus compound having an isocyanurate ring represented by chemical formula (I).

(In the formula, R ¹ represents an alkyl group, an aryl group, or a benzyl group having 1 to 20 carbon atoms, and R ² represents a group represented by formula (1). Alternatively, R ¹ and R ² may be linked to form a ring. R ³ may be the same or different and represents an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms. R ⁴ may be the same or different and represents an alkenyl group having 2 to 20 carbon atoms or an alkynyl group having 2 to 20 carbon atoms. Y may be the same or different and represents an alkylene group having 1 to 20 carbon atoms.)

(In the formula, R ³ , R ⁴ and Y are the same as defined above.) 2. The method for synthesizing a phosphorus compound having an isocyanurate ring according to claim 1, characterized in that the phosphorus compound represented by chemical formula (II) is reacted with an isocyanurate compound represented by chemical formula (III).

(In the formula, R ¹ is the same as defined above, R ⁸ represents -Y-X, or R ¹ and R ⁸ may be linked to form a ring. Y is the same as defined above. X may be the same or different and represents a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a mesyloxy group (OMs), a tosyloxy group (OTs), or a trifluoromethanesulfonyloxy group (OTf).)

(In the formula, ^R3 and ^R4 are the same as defined above.) A flame retardant containing a phosphorus compound having an isocyanurate ring according to claim 1. A resin composition containing the phosphorus compound having an isocyanurate ring according to claim 1 and a resin component. The resin composition according to claim 4, characterized in that the resin component is a polyphenylene ether resin. A prepreg comprising the resin composition according to claim 4 or claim 5 and a substrate. A resin-coated metal foil comprising a resin layer containing the resin composition according to claim 4 or claim 5 or a semi-cured product of the resin composition, and a metal foil. A thermosetting resin film formed from the resin composition according to claim 4 or 5. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to claim 4 or 5, and a metal foil. A printed wiring board comprising an insulating layer containing a cured product of the resin composition according to claim 4 or claim 5, or a cured product of the thermosetting resin film according to claim 8, and wiring. An adhesive comprising the resin composition according to claim 4 or claim 5.

Images