JP2023160193A - Curable resin composition, dry film, prepreg, cured product, laminate and electronic component - Google Patents

Abstract

To provide a curable resin composition, a cured product of which has low dielectric constants and low dielectric loss tangents.SOLUTION: A curable resin composition includes: an episulfide resin; and at least one curing agent selected from the group consisting of a maleimide compound, a benzoxazine compound and a carbodiimide compound.SELECTED DRAWING: None

Description

The present invention relates to a curable resin composition, a dry film, a prepreg, a cured product, a laminate, and an electronic component.

In recent years, mobile communication devices compatible with the 5th generation mobile communication system (5G) have appeared, and even the 6th generation mobile communication system (5G) has appeared.
Development has begun with the next generation in mind. In mobile communication devices and the like, the use of electrical signals in high frequency bands (on the order of GHz) is increasing in order to transmit and process large amounts of information at high speed. Signals in high frequency bands are easily attenuated, and the materials used must be designed to suppress transmission loss.

Against this background, development of materials having low dielectric constants and low dielectric loss tangents that make it possible to reduce transmission loss is progressing.

Conventionally, epoxy resin has been used as a material having a low dielectric constant and a low dielectric loss tangent, but for example, Patent Document 1 proposes a resin material using an episulfide resin. The resin material of Patent Document 1 includes an episulfide resin, a curing agent, and an inorganic filler, and the curing agent is an active ester compound or a cyanate ester compound.

JP2013-60553A

However, the resin material of Patent Document 1 requires an active ester compound or a cyanate ester compound, and further an inorganic filler. There is still a need for resin materials that achieve tangent.

An object of the present invention is to provide a resin material whose cured product has a low dielectric constant and a low dielectric loss tangent.

The present inventors have developed a curable resin composition that combines an episulfide resin with one or more curing agents selected from the group consisting of a maleimide compound, a benzoxazine compound, and a carbodiimide compound. The present invention was completed based on the discovery that it is possible to provide a product.
In these resin compositions, for example, the thiirane group and maleimide group have flexibility (elongation rate) by forming carbon-sulfur bonds in the curing reaction, and an excellent cured product can be obtained due to the low dielectric constant. Thiirane groups and benzoxazine groups have low thermal expansion due to the ring opening of the benzoxazine group promoted by the acidity of the thiol generated by ring opening of the thiirane group, and the ring opening of the thiirane group promoted by the hydroxyl group generated by ring opening of the benzoxazine group. The thiirane group and the carbodiimide group form an imidazolidinethione ring bond in the curing reaction, and a cured product with excellent low thermal expansion and heat resistance can be obtained.

The gist of the present invention is as follows.
[1] A curable resin composition comprising an episulfide resin and one or more curing agents selected from the group consisting of maleimide compounds, benzoxazine compounds, and carbodiimide compounds.
[2] The curable resin composition according to [1], wherein the ratio of the number of moles of the functional group of the curing agent to the number of moles of the thiirane group contained in the episulfide resin is 0.1 or more and 1.5 or less.
[3] The curable resin composition of [1] or [2], further comprising an inorganic filler.
[4] A dry film formed by forming a resin layer made of the curable resin composition according to any one of [1] to [3] on a base material.
[5] A prepreg obtained by impregnating a base material with the curable resin composition according to any one of [1] to [3].
[6] The curable resin composition according to any one of [1] to [3], the curable resin composition in the resin layer of the dry film according to [4], or the curable resin composition in the prepreg according to [5] A cured product.
[7] A laminate containing the cured product of [6].
[8] An electronic component containing the cured product of [6].

According to the curable resin composition of the present invention, a cured product having a low dielectric constant and a low dielectric loss tangent can be provided.

<Curable resin composition>
The curable resin composition of the present invention includes an episulfide resin and one or more curing agents selected from the group consisting of maleimide compounds, benzoxazine compounds, and carbodiimide compounds.

[Episulfide resin]
The episulfide resin is not particularly limited, and a resin having one or more thiirane groups can be used. From the viewpoint of good curability and mechanical strength of the cured product, the number of thiirane groups is preferably 2 or more, more preferably 2 or more and 4 or less.

Examples of episulfide resins having two or more thiirane groups include bisphenol A type episulfide resin, bisphenol F type episulfide resin, bisphenol S type episulfide resin, hydrogenated bisphenol A type episulfide resin, hydrogenated bisphenol F type episulfide resin, and hydrogenated bisphenol S type episulfide resin. Type episulfide resin, dicyclopentadiene type episulfide resin, biphenol type episulfide resin, fluorene type episulfide resin, episulfide resin having a triazine nucleus in its skeleton, naphthalene type episulfide resin, anthracene type episulfide resin, naphthol aralkyl type episulfide resin, etc.
Polyfunctional episulfide resins such as phenol novolac type episulfide resin, biphenyl novolac type episulfide resin, and phenol aralkyl type episulfide resin may be used.
Aliphatic episulfide resins such as episulfide resins having a tricyclodecane skeleton and episulfide resins having an adamantane skeleton may also be used.

The episulfide resin is preferably an episulfide resin such as bisphenol A type, bisphenol F type, or biphenyl, or an episulfide resin having a hydrogenated (alicyclic) structure, and has a hydrogenated (alicyclic) structure from the viewpoint of achieving lower dielectric properties. Episulfide resins are more preferred.

The episulfide resins may be used alone or in combination of two or more in any ratio.

The molecular weight of the episulfide resin can be 200 or more and 2,000 or less, preferably 350 or more from the viewpoint of safety, and preferably 1,000 or less from the viewpoint of handling properties such as fluidity in the composition. .
Molecular weight in this specification means number average molecular weight unless otherwise specified.

The episulfide equivalent of the episulfide resin (mass of resin per equivalent of episulfide group) can be 100 or more and 1,000 or less. It is preferably 500 or less because good reactivity can be obtained.

Episulfide resins can be easily obtained by converting the epoxy groups of epoxy resins into thiirane groups using a sulfurizing agent. Examples of the sulfurizing agent include thiourea and potassium thiocyanate. In order to suppress the polymerization reaction due to ring opening of the thiirane group, the reaction temperature is preferably 70° C. or lower. The reaction temperature can be set to 40° C. or higher in terms of reaction efficiency.

[Curing agent]
The curing agent is selected from the group consisting of maleimide compounds, benzoxazine compounds and carbodiimide compounds. It may be any one of a maleimide compound, a benzoxazine compound, and a carbodiimide compound, or it may be a combination of two or all of these in any ratio.
Among these, maleimide compounds are preferred because they have good mechanical properties and low dielectric constant, and benzoxazine compounds are preferred because they provide good thermal dimensional stability, and they have good thermal dimensional stability and high heat resistance. Carbodiimide compounds are preferred from the viewpoint of availability.

(maleimide compound)
The maleimide compound is not particularly limited, and a compound having one or more maleimide groups can be used. From the viewpoint of good curability and toughness of the cured product, the number of maleimide groups is preferably 2 or more, more preferably 2 or more and 4 or less.

Examples of the maleimide compound include polyfunctional aliphatic maleimide and polyfunctional aromatic maleimide. The polyfunctional aliphatic maleimide includes a maleimide containing an alicyclic structure, and the aromatic ring in the polyfunctional aromatic maleimide may be a carbocyclic ring or a heterocyclic ring.

Examples of polyfunctional aliphatic maleimides include maleimide ester compounds with an isocyanurate skeleton obtained by dehydrating and esterifying tris(hydroxyethyl)isocyanurate and aliphatic maleimide carboxylic acid; tris(carbamatehexyl)isocyanurate and aliphatic maleimide Isocyanuric skeleton polymaleimides such as isocyanurate skeleton maleimide urethane compounds obtained by urethanizing alcohol; dehydration esterification of aliphatic maleimide carboxylic acid and various aliphatic polyols, or aliphatic maleimide carboxylic acid ester and various aliphatic polyols; Aliphatic polymaleimide ester compounds obtained by transesterification with a polyol; aliphatic polymaleimide ester compounds obtained by ether ring-opening reaction of aliphatic maleimide carboxylic acid and various aliphatic polyepoxides; aliphatic maleimide alcohol Examples thereof include aliphatic polymaleimide urethane compounds obtained by a urethanization reaction of and various aliphatic polyisocyanates.

As polyfunctional aromatic maleimide, aromatic polymaleimide ester compounds obtained by dehydration esterification of maleimide carboxylic acid and various aromatic polyols, or transesterification reaction of maleimide carboxylic acid ester and various aromatic polyols; maleimide Aromatic polymaleimide ester compounds obtained by ether ring-opening reaction of carboxylic acid and various aromatic polyepoxides; Aromatic polymaleimide urethane compounds obtained by urethanization reaction of maleimide alcohol and various aromatic polyisocyanates, etc. can be mentioned.

Polyfunctional aliphatic maleimides and polyfunctional aromatic maleimides can include heterocycles, and specifically include tetracarboxylic dianhydrides (e.g., alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, etc.) and diamines. (For example, a diamine with an aliphatic chain structure, an aromatic diamine, etc.) A maleimide group-containing imide compound in which a terminal amine is sealed with maleic anhydride; a dicarboxylic acid derivative and a bis(o-aminophenol) are polymerized. There are maleimide group-containing benzoxazole compounds whose terminal amines are capped with maleic anhydride.

The maleimide compound is preferably a maleimide compound containing an alicyclic structure in the skeleton from the viewpoint of improving the low dielectric properties of the cured product, and preferably a maleimide compound containing an aliphatic chain in the skeleton from the viewpoint of increasing the toughness of the cured product. From the viewpoint of increasing the rigidity of the cured product, maleimide compounds containing an aromatic ring, a heterocycle, or a structure in which these rings are condensed in the skeleton are preferred.

The molecular weight of the maleimide compound can be 300 or more and 8,000 or less. From the viewpoint of flexibility of the cured product, it is preferably 1,000 or more.

The maleimide equivalent of the maleimide compound (mass of the compound per equivalent of maleimide group) can be 150 or more and 4,000 or less. The maleimide equivalent is preferably 1,000 or more from the viewpoint of the toughness of the cured product.

These maleimide compounds may be synthesized by known methods, or commercially available products may be used.
Commercially available products include, for example, BMI, BMI-70 and BMI-80 (manufactured by KAI Kasei Co., Ltd.), BMI-1000, BMI-1000H, BMI-1000S, BMI-1100, BMI-1100H, BMI-2000, BMI-2300, BMI-3000, BMI-3000H, BMI-4000, BMI-5100, BMI-7000, BMI-7000H, and BMI-TMH (manufactured by Daiwa Chemical Industries, Ltd.), MIA-200 (manufactured by DIC), BMI- Examples include BMI-2500, BMI-3000J, BMI-6000, and BMI-6100 (manufactured by Designer Molecules), SLK-2600 (manufactured by Shin-Etsu Chemical Co., Ltd.), and MIR-3000-70MT (manufactured by Nippon Kayaku Co., Ltd.).

(Benzoxazine compound)
The benzoxazine compound is not particularly limited, and a compound having one or more benzoxazine rings can be used. From the viewpoint of good curability and brittleness of the cured product, the number of benzoxazine rings is preferably 2 or more, more preferably 2 or more and 4 or less.

As the benzoxazine compound, a known benzoxazine compound can be used, such as a P-d type benzoxazine compound, a F-a type benzoxazine compound, an ALP-d type benzoxazine compound, a T-ala type benzoxazine compound, etc. can be mentioned.

The benzoxazine compounds may be used alone or in combination of two or more in any ratio.

The molecular weight of the benzoxazine compound can be 300 or more and 2,000 or less, preferably 300 or more and 1,000 or less.

The benzoxazine equivalent (mass of the compound per equivalent of benzoxazine ring) of the benzoxazine compound can be 150 or more and 1,000 or less. The benzoxazine equivalent is preferably 500 or less, more preferably 300 or less.

(Carbodiimide compound)
The carbodiimide compound is not particularly limited, and a compound containing two or more carbodiimide groups (-N=C=N-) can be used. From the viewpoint of good curability, the number of carbodiimide groups is preferably 2 or more, more preferably 2 or more and 10 or less.

A carbodiimide compound can be synthesized by a known method (for example, see JP-A-2019-38960). Specifically, it can be synthesized by condensation polymerization of diisocyanate.

Diisocyanates used in the synthesis of carbodiimide compounds include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. Specifically, 1,5-naphthylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4- Aromatic diisocyanates such as phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, tetramethylxylylene diisocyanate, methylene diisocyanate, tetramethylene diisocyanate, hexa Aliphatic diisocyanates such as methylene diisocyanate and trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexane diisocyanate, 2,5-bis(isocyanatomethyl)bicyclo[ Examples include alicyclic diisocyanates such as 2.2.1]heptane and 2,6-bis(isocyanatomethyl)bicyclo[2.2.1]heptane.
These diisocyanates may be used alone or in combination of two or more, and from the viewpoints of reactivity and heat resistance as a cured product, aromatic diisocyanates, solubility in organic solvents, flexibility as a cured product, and low From the viewpoint of dielectric properties, aliphatic diisocyanates and alicyclic diisocyanates can be used as appropriate.
In particular, as the carbodiimide compound used in the present invention, 2,4'-diphenylmethane diisocyanate and 4 , 4'-diphenylmethane diisocyanate are preferably used in condensation polymerization.

In the carbodiimide compound thus obtained, it is preferable that the terminal isocyanate group is subjected to a capping reaction with a compound having one functional group that reacts with an isocyanate group. Compounds that react with this isocyanate group include monoisocyanates, monoalcohols, monoamines, acid anhydrides, and the like.

Examples of the monoisocyanate include lower alkyl isocyanates such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, n-, sec- or tert-butyl isocyanate, alicyclic aliphatic isocyanates such as cyclohexyl isocyanate, phenyl isocyanate, tolyl isocyanate, dimethyl Examples include aromatic isocyanates such as phenyl isocyanate and 2,6-diisopropylphenyl isocyanate.
Examples of monoalcohols include methanol, ethanol, cyclohexanol, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, and the like.
Examples of the monoamine include primary amines such as butylamine and cyclohexylamine, and secondary amines such as diethylamine, dibutylamine, and dicyclohexylamine.
Examples of the acid anhydride include phthalic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, benzoic anhydride, and the like.
These may be used alone or in combination of two or more. Among these, from the viewpoint of reactivity, phenyl isocyanate and tolylisocyanate are preferred, and phenyl isocyanate is more preferred.

The carbodiimide compounds may be used alone or in combination of two or more in any ratio.

The molecular weight of the carbodiimide compound can be 500 or more and 8,000 or less, and from the viewpoint of good film-forming properties, it is preferably 1,000 or more, more preferably 1,400 or more. In terms of compatibility, it is preferably 5,000 or less, more preferably 3,500 or less.

The carbodiimide equivalent (mass of the compound per equivalent of carbodiimide group) of the carbodiimide compound can be 50 or more and 4,000 or less. From the viewpoint of toughness of the cured product, it is preferably 100 or more, more preferably 130 or more, and from the viewpoint of good curability, it is preferably 1,000 or less, more preferably 500 or less, and even more preferably 260. It is as follows.

[Amount]
In the curable resin composition of the present invention, the ratio of the number of moles of the functional group of the curing agent to the number of moles of the thiirane group contained in the episulfide resin is preferably 0.1 or more and 1.5 or less. Within this range, the thiirane group and the functional group of the curing agent react in just the right amount, making it possible to achieve both excellent low dielectric properties, mechanical properties, and thermal properties.
Here, the functional group of the curing agent is a maleimide group for a maleimide compound, a benzoxazine ring for a benzoxazine compound, and a carbodiimide group for a carbodiimide compound.
Specifically, the ratio of the number of moles of maleimide groups in the maleimide compound to the number of moles of thiirane groups contained in the episulfide resin is 0.1 or more and 0.5 or less, since a cured product with excellent mechanical properties can be obtained. is more preferable, and the ratio of the number of moles of the benzoxazine ring of the benzoxazine compound to the number of moles of the thiirane group contained in the episulfide resin is 0.1 or more and 1.5 or more, since a cured product with excellent thermal properties can be obtained. The following is more preferable, and the ratio of the number of moles of the carbodiimide group of the carbodiimide compound to the number of moles of the thiirane group contained in the episulfide resin is 0.8 or more and 1.5 or less, since a cured product with excellent thermal properties can be obtained. is more preferable.

In the curable resin composition of the present invention, the total proportion of the episulfide resin and one or more curing agents selected from the group consisting of maleimide compounds, benzoxazine compounds, and carbodiimide compounds in the nonvolatile components is 30% by mass or more. The content is preferably 40% by mass or more, and more preferably 40% by mass or more.

[Optional ingredients]
The curable resin composition of the present invention contains optional ingredients in addition to an episulfide resin and one or more curing agents selected from the group consisting of a maleimide compound, a benzoxazine compound, and a carbodiimide compound, within a range that does not impair the effects of the present invention. can include.

(Inorganic filler)
From the viewpoint of improving the thermal dimensional stability of the cured product, it is preferable to incorporate an inorganic filler. Inorganic fillers are not particularly limited, and include silica (fused silica, amorphous silica, crystalline silica, etc.), talc, barium sulfate, barium titanate, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, alumina. , silicon nitride, boron nitride, aluminum nitride, and the like. Among them, silica is preferred from the viewpoint of low thermal expansion and low dielectric loss tangent.

The average particle diameter of the inorganic filler can be 0.1 μm or more and 1.0 μm or less, and preferably 0.3 μm or more from the viewpoint of reducing the dielectric constant. Here, the average particle diameter is a value measured using a laser analysis type particle size distribution analyzer.

The inorganic filler may be surface-treated with a coupling agent. Examples of the coupling agent include a silane coupling agent and a titanate coupling agent.

The content of the inorganic filler is not particularly limited, but from the viewpoint of obtaining sufficient blending effects, it is preferably 40% by mass or more, more preferably 50% by mass of the nonvolatile components of the curable resin composition of the present invention. % or more. Further, the content is preferably 80% by mass or less, more preferably 75% by mass or less.
When using an inorganic filler, the inorganic filler may be used alone or in combination of two or more in any ratio.

(hardening accelerator)
From the viewpoint of curing speed and controlling the crosslinked structure of the cured product, it is preferable to include a curing accelerator. The curing accelerator is not particularly limited, and examples thereof include imidazole compounds, amine compounds, phosphorus compounds, organometallic complexes, and organometallic salts.
Examples of imidazole compounds include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-( Examples include 2-cyanoethyl)-2-ethyl-4-methylimidazole.
Examples of amine compounds include dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, 4-methyl-N,N-dimethylbenzylamine, etc. The following amine compounds are mentioned.
Examples of the phosphorus compound include triphenylphosphine.
Examples of organometallic complexes or organometallic salts include acetylacetonate complexes such as cobalt, copper, zinc, iron, nickel, and manganese.

The content of the curing accelerator is not particularly limited, but from the viewpoint of obtaining sufficient blending effects, the content of the curing accelerator is preferably 0.05% by mass or more, more preferably 0.05% by mass or more based on the solid content of the curable resin composition of the present invention. .1% by mass or more. Moreover, it is preferably 1% by mass or less, more preferably 0.6% by mass or less.
When using a curing accelerator, the inorganic filler may be used alone or in combination of two or more in any ratio.

(Thermoplastic resin)
The curable resin composition of the present invention can contain a thermoplastic resin for film-forming properties, flexibility, adhesion, and the like. Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, thermoplastic elastomer, and the like.
When a thermoplastic resin is used, the inorganic filler may be used alone or in combination of two or more in any ratio.

(solvent)
The curable resin composition of the present invention can contain a solvent to adjust the viscosity during coating. The solvent is not particularly limited, and organic solvents are preferred. For example, ketones such as acetone, methyl ethyl ketone, and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, Glycol ethers such as dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, diethylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene Esters such as glycol ethyl ether acetate and propylene glycol butyl ether acetate; Alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; Aliphatic hydrocarbons such as octane and decane; Petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvents Examples include petroleum solvents such as naphtha; aprotic polar solvents such as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and acetonitrile. From the viewpoint of solubility and volatility during curing, ketones, esters, etc. are preferred.
The solvents may be used alone or in combination of two or more in any ratio.

(Other ingredients)
The curable resin composition of the present invention may contain other components as long as the effects of the present invention are not impaired. For example,; conductive particles; colorants; wetting and dispersing agents; ultraviolet absorbers; silane coupling agents; plasticizers; flame retardants; antistatic agents; antiaging agents; antioxidants; antibacterial and antifungal agents; antifoaming agents; Leveling agents; thickeners; adhesion agents; thixotropy agents; mold release agents; surface treatment agents; dispersants; dispersion aids; surface modifiers; stabilizers; phosphors.

The curable resin composition of the present invention is thermosetting, and includes various components (e.g., compounds having ethylenically unsaturated groups such as photopolymerizable monomers and photopolymerizable oligomers; photopolymerization initiators, photoacid generators, etc.). Photosensitivity and photocurability may be imparted by incorporating a photosensitive agent such as a photobase generator, a photobase generator, a photoinitiation aid, a sensitizer, etc.).

The curable resin composition of the present invention may contain thermosetting resins other than episulfide resins (for example, epoxy resins, oxetane resins, etc.), but preferably does not contain them. Further, although it may contain a curing agent other than the maleimide compound, benzoxazine compound, and carbodiimide compound (for example, an active ester compound, a cyanate ester compound, etc.), it is preferably not included.

[Production method]
The curable resin composition of the present invention can be prepared by mixing one or more curing agents selected from the group consisting of episulfide resins, maleimide compounds, benzoxazine compounds, and carbodiimide compounds, and optional components. The viscosity of the composition is preferably from 100 mPa·s to 100,000 mPa·s from the viewpoint of coatability. The viscosity can be adjusted by blending a solvent, and the solvent can be blended in an arbitrary amount in view of compatibility with the components in the composition, coating properties, and drying properties of the composition.

<Dry film>
The curable resin composition of the present invention can be made into a dry film by coating and drying on a substrate to form a resin layer.
Examples of the base material include metal foil (eg, copper foil, etc.), carrier film, and the like.
The carrier film is not particularly limited, and for example, films such as polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and polystyrene films may be used. I can do it.
The coating and drying methods are not particularly limited, and known methods can be used.
A protective film may be laminated on the surface of the resin layer of the dry film. Examples of the protective film include polyester film, polyethylene film, polypropylene film, and the like.

<Prepreg>
The curable resin composition of the present invention can be impregnated into a base material to form a prepreg. Examples of the base material include glass cloth, glass nonwoven fabric, aramid nonwoven fabric, and the like. After a base material is impregnated with the curable resin composition, it may be dried to obtain a semi-cured product.

<Cured product>
A cured product can be obtained by curing the curable resin composition of the present invention, the resin layer of the dry film of the present invention, and the curable resin composition in the prepreg of the present invention. When using the curable resin composition of the present invention, a cured product can be obtained by applying the composition to a desired object, drying it, and heating it at a temperature of 160° C. or higher and 280° C. or lower. The heating time can be set as appropriate, and can be, for example, 30 minutes or more and 120 minutes or less. When using the dry film of the present invention, a cured product of the resin layer can be obtained by laminating the dry film on a desired object and heating it at a temperature of 160° C. or higher and 280° C. or lower. The heating time can be set as appropriate, and can be, for example, 40 minutes or more and 90 minutes or less.

<Laminated board>
The present invention also relates to a laminate containing the cured product of the present invention. The laminate of the present invention can be produced using the prepreg of the present invention. For example, by stacking one or more prepregs of the present invention, further stacking metal foil such as copper foil on both or one side of the upper and lower sides, and heating and press-molding the laminate, a double-sided integrated laminated product can be obtained. A laminate having a metal foil on one side or a metal foil on one side and a cured product of a curable resin composition can be obtained.

<Electronic parts>
The present invention further relates to an electronic component containing the cured product of the present invention. Examples of electronic components include printed wiring boards and inductors. Electronic components comprising the cured product of the present invention are preferable for use as cured films such as solder resists, interlayer insulating materials, and coverlays, and as fillers for through holes, via holes, and the like.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples.

The following ingredients were used.
<Episulfide resin>
Episulfide resin 1: TBIS-AHSP manufactured by Taoka Chemical Industry Co., Ltd. Hydrogenated bisphenol A type episulfide resin, episulfide equivalent 214g/eq
Episulfide resin 2: A bisphenol A type episulfide resin obtained by converting the epoxy group of Epoxy Resin 2 below into a thiirane group as follows. Episulfide equivalent: approximately 207g/eq
A solution obtained by dissolving 2.1 g of thiourea in 42 mL of methanol in a 50 mL vial was added to a 120 mL vial containing a solution of 22.9 g of epoxy resin 2 dissolved in 18 mL of tetrahydrofuran (THF) at room temperature (about 25 °C). ) was added dropwise over 6 minutes, the temperature was raised to 50°C, and maintained at that temperature for 2 and a half hours. It was then cooled to room temperature and left for 24 hours.
The obtained reaction solution was transferred to a 200 mL flask using 10 mL of methanol, concentrated using an evaporator, then 29 mL of distilled water was added, extracted with 32 mL of ethyl acetate (AcOEt), and further extracted with 16 mL of AcOEt. After washing the extract with 30 mL of brine, it was dried over magnesium sulfate, filtered, and the solvent was distilled off to obtain 3.7 g of bisphenol A episulfide resin as a residue.

<Other resins>
Epoxy resin 1: YX-8034 manufactured by Mitsubishi Chemical Corporation. Hydrogenated bisphenol A type epoxy resin, epoxy equivalent 270g/eq
Epoxy resin 2: JER828 manufactured by Mitsubishi Chemical Corporation. Bisphenol A type epoxy resin, epoxy equivalent 185g/eq
Thiol compound: SS32 manufactured by Kawaguchi Chemical Industry Co., Ltd. Trifunctional thiol compound, molecular weight 532. Thiol equivalent: 177.3g/eq

<Curing agent>
Maleimide compound: BMI-6000 manufactured by Designer Molecules, terminal bismaleimide resin, number average molecular weight 6626, weight average molecular weight 21733, maleimide equivalent weight 3313 g/eq
Benzoxazine compound: P-d type benzoxazine compound manufactured by Shikoku Kasei Co., Ltd., molecular weight 435, benzoxazine equivalent weight 217.5 g/eq
Carbodiimide compound: A compound prepared as follows. Number average molecular weight 2997, weight average molecular weight 17193, carbodiimide group equivalent weight 205g/eq
A mixture of 54 parts by mass of 2,4'-diphenylmethane diisocyanate and 46 parts by mass of 4,4'-diphenylmethane diisocyanate (manufactured by Tosoh Corporation, Monomeric MDI; Millionate NM), an isocyanate group was placed in a reaction vessel equipped with a reflux tube and a stirrer. 10 parts by mass of phenyl isocyanate as a compound having one functional group that reacts with , and 0.6 parts by mass of 3-methyl-1-phenyl-2-phosphorene-1-oxide as a carbodiimidation catalyst were added, and the mixture was heated for 100 minutes under a nitrogen stream. The mixture was stirred at ℃ for 2 hours, and it was confirmed by infrared absorption (IR) spectroscopy that the absorption peak due to isocyanate groups at a wavelength of around 2270 cm ^-1 had almost disappeared, and a carbodiimide compound was obtained.
Active ester compound: HPC-8000-65T manufactured by DIC, non-volatile component 65% by weight, active ester group equivalent 223 g/eq
Cyanate compound: BA-230S manufactured by Lonza Japan, non-volatile component 75% by weight, cyanate ester group equivalent 235g/eq

<Other ingredients>
Inorganic filler: silica filler (spherical, average particle size 0.5 μm)
Solvent 1: Cyclohexanone Solvent 2: Methyl ethyl ketone

Various measurements were performed as follows.
<Preparation of resin composition>
Each component was mixed in the amount shown in Table 1 (in Table 1, the amount of each component is expressed in parts by mass) at 2000 rpm using a revolving agitation degassing device (manufactured by Photo Chemical Co., Ltd., Kakuhunter SK-300S). The mixture was stirred for 1 minute and defoamed at 2200 rpm for 2 minutes to produce compositions of Examples and Comparative Examples.

<Preparation of cured film>
The compositions of Examples and Comparative Examples were applied to copper foil using an applicator and dried at 90° C. for 10 minutes in a box drying oven. Next, the copper foil with the dried coating film was placed in a drying oven where the temperature inside the oven was room temperature (about 25 ° C.), and after raising the temperature to the temperature shown in Table 1 over 30 minutes, it was held at that temperature for 1 hour, Heat treatment was performed. The copper foil with the cured coating film was taken out of the drying oven, the copper foil was removed with an etching solution, and the copper foil was washed with water to obtain a cured film with a thickness of about 30 μm.

<Dielectric properties>
The cured film produced by the above method was dried at 120° C. for 10 minutes in a box drying oven, and the dielectric constant and dielectric loss tangent at 10 GHz were measured using the SPDR method.

<Mechanical properties>
A film sample consisting of a cured product of each composition produced in the same manner as above was cut into a 5 mm width x 70 mm length to prepare a test piece.
This test piece was subjected to tensile test measurements five times using EZ-SX manufactured by Shimadzu Corporation, with a distance between the grips of 30 mm and a tensile speed of 3 mm/min.
The elastic modulus at a tensile strength of 5 to 10 MPa was measured, and the average value was taken as the elastic modulus (GPa). The stress until the test piece broke was measured, and the average value of the maximum values was taken as the maximum point stress (MPa). The elongation rate until the test piece broke was measured, and the maximum value was taken as the tensile elongation rate at break (%).

<Thermal properties>
The cured film produced by the above method was cut into pieces 3 mm wide x 30 mm long, and measured using a TMA "Q400-1330" manufactured by TA Instruments at a heating rate of 10°C/min and a measurement temperature range of 30 to 300°C. , thermal expansion coefficient and glass transition temperature were measured.

As shown in Table 1, the cured products of the examples have a low dielectric constant and a low dielectric loss tangent, and are particularly improved in terms of the low dielectric loss tangent compared to the comparative examples combined with epoxy resins or thiol compounds. It can be seen that
Among them, Examples 1 and 2 in which a maleimide compound was used as a curing agent showed remarkable improvement in maximum point stress and elongation at break.
Furthermore, Example 4, which used a carbodiimide compound as a curing agent, had an improved coefficient of thermal expansion and a high glass transition temperature.

Cured in the same manner as above, except that the resin compositions of Examples and Comparative Examples were prepared using each component in the amounts shown in Table 2 (in Table 2, the amounts of each component are expressed in parts by mass). A membrane was prepared and various properties were measured. The resin composition shown in Table 2 contains an inorganic filler.

As shown in Table 2, even when an inorganic filler was used, the cured products of the examples had a low dielectric constant and a low dielectric loss tangent, and were particularly low compared to the comparative example combined with an epoxy resin. It can be seen that the dielectric loss tangent has improved.
Among them, Example 5 in which a maleimide compound was used as a curing agent showed remarkable improvement in maximum point stress and elongation at break.
Further, Example 7, which used a carbodiimide compound as a curing agent, had an improved coefficient of thermal expansion and a high glass transition temperature.
On the other hand, it can be seen that Comparative Examples 6 and 7, in which an active ester compound or a cyanate compound was used as a curing agent, had poorer induction characteristics than the Examples.

According to the curable resin composition of the present invention, a cured product having a low dielectric constant and a low dielectric loss tangent can be provided, so that it is highly useful industrially.

Claims (8)

A curable resin composition comprising an episulfide resin and one or more curing agents selected from the group consisting of maleimide compounds, benzoxazine compounds, and carbodiimide compounds. The curable resin composition according to claim 1, wherein the ratio of the number of moles of the functional group of the curing agent to the number of moles of the thiirane group contained in the episulfide resin is 0.1 or more and 1.5 or less. The curable resin composition according to claim 1, further comprising an inorganic filler. A dry film comprising a resin layer formed from the curable resin composition according to any one of claims 1 to 3 on a base material. A prepreg obtained by impregnating a base material with the curable resin composition according to any one of claims 1 to 3. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 3. A laminate comprising the cured product according to claim 6. An electronic component comprising the cured product according to claim 6.