TW202323434A - Thermosetting composition, resin film, prepreg, metal-clad laminate, and printed wiring board - Google Patents

Abstract

Provided is a thermosetting composition containing a polyphenylene ether and an organic peroxide, wherein the polyphenylene ether has an ethylenic unsaturated double bond at a molecular end, the organic peroxide includes a dialkyl peroxide represented by general formula (1) and a t-alkyl hydroperoxide, and the t-alkyl hydroperoxide is is contained in an amount of 0.02-10 parts by mass per 100 parts by mass of the dialkyl peroxide. The thermosetting composition yields a polyphenylene ether cured product having exceptional dielectric properties and heat resistance, the thermosetting composition resisting gelation and having exceptional fluidity even under high temperature such as in a step for drying a contained solvent.

Description

Thermosetting composition, resin film, prepreg, metal foil-clad laminate and printed circuit board

The invention relates to a thermosetting composition, a resin film, a prepreg, a metal foil-clad laminate and a printed circuit board.

In recent years, with the remarkable advancement of information network technology and the expansion of services utilizing the information network, electronic devices capable of increasing the amount of information and increasing the processing speed are required. The increase in the amount of information and the increase in processing speed are further accelerated due to the popularization of 5G, etc. For electronic circuit substrate materials such as printed circuit boards used in electronic equipment, it is required to have low dielectric constant and low dielectric loss. Tangent performance.

As a resin for a thermosetting composition, polyphenylene ether having excellent dielectric properties (low dielectric constant and low dielectric loss tangent) is attracting attention as an electronic circuit board material that can meet the above requirements (Patent Documents 1 and 2 ).

Known technical literature

patent documents

Patent Document 1: International Publication No. 2008/033612

Patent Document 2: Japanese Patent Laid-Open No. 2019-172725

Technical problem to be solved by the present invention

Curing and processing of a polyphenylene ether-containing thermosetting composition (hereinafter referred to as a polyphenylene ether composition) for electronic circuit board materials is performed at a high temperature of 190° C. or higher. If the heat resistance of the cured product obtained by curing the polyphenylene ether composition (hereinafter referred to as polyphenylene ether cured product) is low, the strength of the polyphenylene ether cured product will decrease during processing, etc. Harsh and longer-term reliability in use. Therefore, the cured polyphenylene ether has heat resistance, but the heat resistance of the conventional cured polyphenylene ether described in Patent Document 1 is not sufficient.

Due to the high viscosity of polyphenylene ether, solvents are used for dilution when processing the polyphenylene ether composition. Therefore, a drying process of the solvent (a process of treating the solvent-diluted composition at a temperature higher than room temperature) is required after that. When the solvent is dried, the organic peroxide may be decomposed to cause gelation, resulting in a problem that fluidity of the composition may be lost. If the fluidity of the composition is lost, voids will be generated in the cured polyphenylene ether, and the uniformity of the cured product will be lost, resulting in a decrease in quality. The polyphenylene ether composition described in Patent Document 2 has technical problems in fluidity during processing, and further improvement is required.

Therefore, the technical problem to be solved by the present invention is to provide a thermosetting composition, which can obtain a polyphenylene ether cured product with excellent dielectric properties and heat resistance, and is not easy to condense even at high temperatures such as the drying process of the solvent contained. Gels, excellent fluidity during processing.

Technical means to solve technical problems

That is, the present invention relates to a thermosetting composition comprising a polyphenylene ether having an ethylenically unsaturated double bond at a molecular terminal and an organic peroxide generally Dialkyl peroxides and tertiary alkyl hydroperoxides represented by formula (1), [Chemical formula 1]

In formula (1), R _is the alkyl group that carbon number is 2～8, with respect to the described dialkyl peroxide of 100 mass parts, described tertiary alkyl hydroperoxide is more than 0.02 mass part and 10 Parts by mass or less.

Furthermore, the present invention relates to a resin film formed from the thermosetting composition, a prepreg obtained by impregnating or applying the thermosetting composition to a fibrous substrate, a resin film or the prepreg A metal foil-clad laminate laminated with metal foil, and a printed wiring board obtained by removing part of the metal foil from the metal foil-clad laminate.

Invention effect

It is presumed that the free radicals generated by the thermal decomposition of the dialkyl peroxide initiate an addition reaction, so that the polyphenylene ether having an ethylenically unsaturated double bond at the molecular end undergoes three-dimensional curing, and the tertiary alkyl hydroperoxide in A small amount of polyphenylene ether decomposes during the curing reaction and contributes to curing, and functions as a radical scavenger. Therefore, the cured polyphenylene ether obtained by curing the thermosetting composition of the present invention has excellent dielectric properties and heat resistance , the thermosetting composition of the present invention can maintain the fluidity of the composition even at high temperature such as the drying process of the contained solvent.

＜Thermosetting composition＞

The thermosetting composition of the present invention contains polyphenylene ether and organic peroxide.

＜Polyphenylene ether＞

The polyphenylene ether contains a phenylene ether unit as a repeating structural unit, and has an ethylenically unsaturated double bond at a molecular terminal. The polyphenylene ethers can be used alone or in combination of two or more.

Specific examples of the structural unit of the polyphenylene ether include poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4 -phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenylene ether), etc., from the dielectric properties and heat resistance From the viewpoint of excellence, poly(2,6-dimethyl-1,4-phenylene ether) is preferred. Further, as specific examples of the structural unit of the polyphenylene ether, for example, 2,6-dimethylphenol and other phenols (for example, 2,3,6-trimethylphenol, 2-methyl- Copolymers of 6-butylphenol, 2-allylphenol, etc.); polyphenylene ether copolymers obtained by coupling 2,6-dimethylphenol with biphenols or bisphenols and in toluene solvent and in the presence of organic peroxides, poly(2,6-dimethyl-1,4-phenylene ether) and the like with phenolic compounds such as bisphenols or triphenols (phenol compound) is heated and undergoes a redistribution reaction to obtain a polyphenylene ether with a linear structure or a branched structure. The phenyl group in the phenylene ether unit may have a substituent, and the polyphenylene ether may contain structural units other than the phenylene ether unit within the range that does not hinder the technical effect of the present invention.

Examples of the ethylenically unsaturated double bond at the end of the polymer include (meth)acryl, styryl, vinylbenzyl, vinyl, allyl, and 1,3-butadienyl wait. Among these, (meth)acryloyl and vinylbenzyl are preferred from the viewpoint of high reactivity during thermosetting and excellent dielectric constant and dielectric loss tangent of cured products.

The number of ethylenically unsaturated double bonds in one molecule of the polyphenylene ether is preferably 1.5-6 on average, more preferably 1.6-4 on average, and still more preferably 1.7-3 on average.

The number of ethylenically unsaturated double bonds in one molecule of the polyphenylene ether can be measured, for example, by measuring the number of hydroxyl groups remaining in the polyphenylene ether, and calculating the number of ethylenically unsaturated double bonds from compounds having ethylenically unsaturated double bonds. The portion that decreases in the number of hydroxyl groups of polyphenylene ether before inactivation. Then, the method of measuring the number of hydroxyl groups remaining in polyphenylene ether can be obtained by taking Polymer Papers, Volume 51, p. 7,480 (1994) (Polymer Papers, vol.51, No.7,480 Based on the method described on page (1994)), tetraethylammonium hydroxide was added to a dichloromethane solution of polyphenylene ether, and the absorbance of the mixed solution at a wavelength of 318 nm was measured.

In addition, the polyphenylene ether preferably has a structure of the following general formula (2). [chemical formula 2]

In the formula (2), X is an arbitrary linking group with a valency, Y is an ethylenically unsaturated double bond at the end of the polymer, and a is 1-6.

In the formula (2), specific examples of X include bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-dihydroxybiphenyl, 2,2'-bisphenol Hydroxybiphenyl, 4,4'-dihydroxy-3,3'5,5'-tetramethylbiphenyl, 4,4'-dihydroxy-2,2',3,3'5,5'-hexa Divalent phenols such as methylbiphenyl, hydroquinone, resorcinol, tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol Trivalent or higher phenols represented by novolaks, o-cresol novolacs, naphthol novolacs, and the like.

From the viewpoint of dielectric properties and impregnation to fibrous substrates, the polyphenylene ether has a number average molecular weight of preferably 800 to 5000, more preferably 900 to 4500, and still more preferably 1000. Above and below 3000.

The number average molecular weight should just be the value measured by the usual molecular weight measuring method, and the polystyrene conversion value etc. which were measured using gel permeation chromatography (GPC) are mentioned. Specifically, after preparing a measurement sample with a sample concentration of 0.2w/vol% (solvent: chloroform), it can be measured using HLC-8220GPC (manufactured by TOSOH CORPORATION) as a measurement device under the following conditions, that is, Column: Shodex GPC KF-405L HQ×3 (manufactured by Showa Denko K.K.); eluent: chloroform; injection volume: 20 μL; flow rate: 0.3 mL/min; column temperature: 40° C.; detector: RI.

The synthesis method of the polyphenylene ether is not particularly limited as long as a modified polyphenylene ether modified with an ethylenically unsaturated double bond can be synthesized. Specifically, a method of reacting a compound having an ethylenically unsaturated double bond and a chlorine atom with a polyphenylene ether before modification, etc. are mentioned. As a compound which has an ethylenically unsaturated double bond and a chlorine atom, (meth)acryloyl chloride, vinylbenzyl chloride, etc. are mentioned, for example. In addition, the said polyphenylene ether can use a commercial item, for example, product name "OPE-2St" (made by Mitsubishi Gas Chemical Company, Inc.), "Noryl SA9000" (manufactured by SABIC Innovative Plastic), etc. are mentioned.

＜Organic peroxides＞

The organic peroxides are dialkyl peroxides represented by the general formula (1) and tertiary alkyl hydroperoxides. [chemical formula 3]

In formula (1), R ₁ is an alkyl group having 2 to 8 carbon atoms.

＜Dialkyl peroxide＞

In the formula (1), examples of R ₁ include ethyl, n-propyl, n-butyl, n-pentyl, neopentyl, 1-cyclohexyl-1-methylethyl, n-octyl etc., preferably ethyl, n-propyl, neopentyl. When R ₁ is 2 or more, the oxygen free radicals generated after the thermal decomposition of the dialkyl peroxide will rapidly undergo β-cracking, thereby converting into carbon free radicals, which can initiate a curing reaction and be introduced into polyphenylene radicals. The lower the polarity of the radicals in the ether cured product, the better the dielectric properties can be improved. On the other hand, when R ₁ is 5 or less, since the molecular weight becomes smaller, the amount of radical generation at the same addition amount increases, so heat resistance can be improved. Therefore, R ₁ is preferably 2-5.

Specific examples of the dialkyl peroxide include, for example, tert-amylcumyl peroxide, tert-hexylcumyl peroxide, 1,1,3,3-tetramethylbutyl phenyl cumyl peroxide, 1-cyclohexyl-1-methylethyl cumyl peroxide, etc., preferably tert-amyl cumyl peroxide, tert-hexyl cumyl peroxide oxide, 1,1,3,3-tetramethylbutylcumyl peroxide. Furthermore, 1,1,3,3-tetramethylbutylcumyl peroxide is particularly preferred.

With respect to 100 parts by mass of the polyphenylene ether, the dialkyl peroxide is preferably 0.1 parts by mass to 5 parts by mass, more preferably 0.2 parts by mass to 3 parts by mass, further preferably 0.5 parts by mass to 2 parts by mass.

The preparation method of the dialkyl peroxide compound is not limited in any way, for example, the following method can be enumerated: comprising making the tertiary alkyl hydroperoxide represented by the general formula (3) and the α- The method of the process (hereinafter referred to as process (A)) that methyl styrene reacts; or the tertiary alkyl hydroperoxide represented by general formula (3) and the 2-phenyl group represented by general formula (5) -The process of reacting 2-propanol (hereinafter referred to as process (B)). [chemical formula 4]

[化學式6]

In formula (3), R ₁ is an alkyl group having 2 to 8 carbon atoms. [chemical formula 5]

[chemical formula 6]

In the process (A), the tertiary alkyl hydroperoxide represented by the general formula (3), the α-methylstyrene represented by the general formula (4), the The 2-phenyl-2-propanol shown can use a commercial item.

In the process (A) and the process (B), from the viewpoint of improving the yield of the target product, it is preferable to make the tertiary alkyl hydroperoxide represented by the general formula (3) relative to 1 Mole of α-methylstyrene represented by the general formula (4) or 1 mole of 2-phenyl-2-propanol represented by the general formula (5), carried out at 1 mole or more reaction, and from the perspective of improving the purity of the target product, it is preferable to react with less than 5 moles.

From the perspective of improving the yield of the target product, the reaction temperature of the process (A) and the process (B) is preferably above 0°C, more preferably above 10°C, and from the point of view of safety, It is preferably below 60°C, more preferably below 50°C.

The reaction time of the process (A) and the process (B) varies depending on the raw materials or reaction temperature, etc., and cannot be generalized, but usually from the perspective of improving the yield of the target product, it is preferably more than 0.5 hours, more preferably It is preferably at least 1 hour, and more preferably at most 5 hours from the viewpoint of safety.

In the preceding process (A) and said process (B), acid catalysts are preferably used. The acid catalyst is not particularly limited, and examples thereof include acetic acid, hydrochloric acid, sulfuric acid, perchloric acid, and the like. The acid catalysts may be used alone or in combination of two or more.

In the process (A) and the process (B), the amount of the acid catalyst used is not particularly limited. From the perspective of improving the yield of the target product, it is generally preferred to The α-methylstyrene represented by the general formula (4) or the 2-phenyl-2-propanol represented by the general formula (5) represented by the general formula (5) of 1 mole is used more than 0.02 mole, and from From the perspective of safety, it is better to use less than 5 moles.

The process (A) and the process (B) can use an organic solvent. The organic solvent is not particularly limited, and is preferably an inert organic solvent in the reaction system. Examples of the organic solvent include nonpolar compounds such as pentane, hexane, and toluene; polar compounds such as isopropanol, acetone, and acetonitrile; and the like. The organic solvents may be used alone or in combination of two or more.

In the process (A) and the process (B), the amount of the organic solvent is not particularly limited, usually relative to 100 parts by mass of α-methylstyrene or 2-phenyl-2-propanol, It is about 3 to 300 parts by mass.

Identification of the obtained target product can be performed using liquid chromatography (LC), gas chromatography (GC), nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), mass spectrometry (MS) and the like.

＜Tertiary Alkyl Hydroperoxide＞

The tertiary alkyl hydroperoxide is not particularly limited. When tertiary alkyl hydroperoxide acts as a curing agent, the generated oxygen free radicals will rapidly undergo β-cracking, thereby converting into carbon free radicals to initiate a curing reaction. Since the lower the polarity of the radicals introduced into the cured polyphenylene ether can improve the dielectric properties, the tertiary alkyl group of hydrogen peroxide preferably has 5 or more carbon atoms. On the other hand, since the molecular weight becomes smaller, the amount of free radicals generated in the same amount added increases, so the heat resistance improves, so the number of carbon atoms in the tertiary alkyl group of hydrogen peroxide is preferably 8 or less. Examples include tert-butyl hydroperoxide, tert-amyl hydroperoxide, tert-hexyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-cumyl hydroperoxide, etc. , preferably tert-amyl hydroperoxide, tert-hexyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide. Furthermore, particularly preferred is 1,1,3,3-tetramethylbutyl hydroperoxide.

The said tertiary alkyl hydroperoxide is 0.02 mass part or more and 10 mass parts or less with respect to 100 mass parts of said dialkyl peroxides. From the viewpoint of inhibiting gelation of the thermosetting composition, the tertiary alkyl hydroperoxide is preferably at least 0.05 parts by mass, more preferably 0.1 parts by mass, relative to 100 parts by mass of the dialkyl peroxide From the above, and from the viewpoint of the heat resistance of the polyphenylene ether cured product, the tertiary alkyl hydroperoxide is preferably 8 parts by mass or less, more preferably 5 parts by mass or less, further preferably 3 parts by mass or less.

The thermosetting composition of the present invention may use a polymerization initiator other than the dialkyl peroxide and tertiary alkyl hydroperoxide of the present invention at the same time within the range that does not impair the effects of the present invention in order to increase productivity and increase the degree of curing. . The polymerization initiator is not particularly limited, and a polymerization initiator generally used in this field can be used, but an oil-soluble polymerization initiator soluble in a thermosetting composition is preferable. These polymerization initiators can be used alone or in combination of two or more.

Specific examples of the polymerization initiator include, for example, peroxydicarbonates such as bis-(4-tert-butylcyclohexyl)peroxydicarbonate, and diacyl peroxides such as diperoxybenzoyl. , tert-butyl peroxy 2-ethylhexanoate, peroxyesters such as tert-butyl benzoate, peroxymonocarbonates such as tert-butyl peroxy 2-ethylhexyl monocarbonate, 1,1-bis(tert-butyl peroxyketal such as cyclohexane, α,α'-bis(tert-butylperoxy)dicumene, 2,5-dimethyl-2,5-bis(tert-butylperoxy ) dialkyl peroxides such as hexyne-3, azo compounds such as 2,2'-azobis(2-methylbutyronitrile), 1-hydroxycyclohexyl phenyl ketone, diphenyl-2,4 ,6-Trimethylbenzoylphosphine oxide, 1-[({1-[9-ethyl-6-(2-methylbenzoyl)-9H-oxazol-3-yl]ethylene} Photopolymerization initiators such as amino)oxy]ethanone and the like.

＜Crosslinking agent＞

From the viewpoint of improving heat resistance, the thermosetting composition of the present invention may contain a polyfunctional monomer. Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra (Meth)acrylates, polyfunctional (meth)acrylates such as dipentaerythritol hexa(meth)acrylate, 1,4-divinylbenzene, 2-acryloylethyl 4-vinylbenzoate Vinylbenzene derivatives such as triallyl isocyanurate (TAIC) and other alkenyl isocyanurate derivatives, triallyl cyanurate (TAC) and other alkenyl cyanurate derivatives, Maleimide derivatives such as 4,4-bismaleimide diphenylmethane, N,N-1,3-phenylene bismaleimide, polybutadiene, etc. have 2 in the molecule Polyfunctional vinyl compounds with more than one vinyl group, etc. Among these, triallyl isocyanurate, triallyl cyanurate, and polybutadiene are preferable because they are excellent in heat resistance. These polyfunctional monomers can be used alone or in combination of two or more.

With respect to 100 parts by mass of the polyphenylene ether, the polyfunctional monomer is preferably 5 parts by mass to 50 parts by mass, more preferably 7 parts by mass to 40 parts by mass, further preferably 10 parts by mass to 30 parts by mass. parts by mass.

A solvent can be further added to the thermosetting composition of the present invention in order to improve viscosity, impregnation to glass cloth, and smoothness of a cured film. The solvent is not particularly limited as long as it can dissolve or disperse the above-mentioned components and is volatilized during drying.

From the viewpoint of solubility, as the solvent, aromatic solvents such as toluene and xylene are preferred; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone and cyclohexanone; Amide solvents such as amine, dimethylacetamide, N-methylpyrrolidone, etc. These solvents can be used alone or in combination of two or more. From the aspects of the solubility of the thermosetting composition in the solvent and the ease of the volatilization process, the amount of the solvent is preferably 10 to 1000 parts by mass, more preferably 20 parts by mass, relative to the solid content of 100 parts by mass of the thermosetting composition. ~500 parts by mass.

The thermosetting composition of the present invention may further contain other components in appropriate combination. Examples of other components include elastomers such as polyisoprene, polybutadiene, styrene butadiene, butyl rubber, ethylene propylene rubber, fluororubber, and silicone rubber, natural silica, and fused silica. , synthetic silica, amorphous silica, hollow silica, alumina, clay, talc and short glass fibers and other inorganic fillers, γ-aminopropyltriethoxysilane, γ-glycidoxy Silane coupling agents, flame retardants, polymerization inhibitors, ultraviolet absorbers, light stabilizers, surfactants, Lubricants, thickeners, defoamers, antistatic agents, pigments, dyes, etc.

＜Resin Film＞

The resin film of the present invention is formed from the thermosetting composition. The resin film contains a thermosetting composition before curing, and a part of the thermosetting composition can be cured. The resin film can be obtained, for example, by drying a resin varnish that is a mixture of the thermosetting composition and the solvent alone, or by drying the resin varnish after coating it on a support such as a support film. The drying removal of the solvent can be performed at 20° C. to 180° C. using a hot air dryer or the like, for example. The drying temperature is preferably 20-150°C, more preferably 50-130°C.

Examples of the support for the resin film include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polycarbonate, etc. Metal foil such as ester, polyimide, ethylene tetrafluoroethylene copolymer, copper foil, aluminum foil, release paper, etc. After coating the thermosetting composition on the metal foil, the material obtained by drying and removing the solvent using a hot air dryer or the like is also called a resin-coated metal foil. In addition, the support may be subjected to chemical or physical treatments such as matte treatment, corona treatment, and mold release treatment.

The resin film is suitably used as an interlayer insulating sheet, an adhesive film, and the like of a laminate such as a multilayer printed wiring board.

＜Prepreg＞

The prepreg of the present invention is a composite of a fibrous substrate and the thermosetting composition. The prepreg contains a thermosetting composition before curing, and a part of the thermosetting composition can be cured. The prepreg is preferably a composite of a fibrous substrate and a thermosetting composition impregnated or coated on the fibrous substrate. When a thermosetting composition is coated on the surface of a fibrous substrate to form a layer, it is also possible to obtain a substrate impregnated with a thermosetting composition by press molding for curing a prepreg. The structure of the cured product. The prepreg can be obtained, for example, by impregnating or coating a substrate such as glass cloth with a resin varnish that is a mixture of the thermosetting composition of the present invention and a solvent, and drying to remove the solvent. In addition, impregnation or coating can be repeated several times. Furthermore, it is also possible to adjust to the final desired impregnation amount by repeating impregnation or coating using a plurality of thermosetting compositions having different concentrations or compositions. Drying and removal of the solvent is carried out using a hot air drier or the like, for example, at 20°C to 180°C. The drying temperature is preferably 20-150°C, more preferably 50-130°C.

Examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, pulp paper, and linter paper. Among these, glass cloth is preferable in order to make the printed wiring board excellent in mechanical strength, and glass cloth subjected to a flattening process is more preferable. These fibrous base materials can be used alone or in combination of two or more. In addition, as the thickness of the fibrous base material, for example, a fibrous base material of 1 to 300 μm can be used.

In the solid content of the prepreg, the ratio of the solid content of the thermosetting composition is preferably 30 to 80% by mass, more preferably 40 to 70% by mass. When the above ratio is less than 30% by mass, the insulation reliability tends to be poor when the prepreg is used for electronic substrates or the like. In addition, when the above ratio exceeds 80% by mass, mechanical properties such as flexural modulus of elasticity tend to be poor when used for electronic substrates and the like.

＜Metal Foil Clad Laminate＞

The metal foil-clad laminate of the present invention is a laminate in which the above resin film or the above prepreg and metal foil are laminated. The laminate can be produced by laminating one or more sheets of the resin film and/or prepreg on a substrate such as metal foil, and then curing the thermosetting composition by compression molding to form an insulating layer. It is also possible to use the resin-coated metal foil instead of the metal foil. Thermoforming can be performed at, for example, a temperature of 180° C. to 240° C., a heating time of 30 minutes to 300 minutes, and a surface pressure of 20 kgf/cm ² to 40 kgf/cm ² .

The said metal foil is not specifically limited, For example, aluminum or copper foil etc. are mentioned, Among these, copper foil is preferable because it has low electrical resistance. As the thickness of the metal foil, for example, a metal foil of 1 to 50 μm can be used.

The resin film and the prepreg combined with the metal foil may be one sheet or a plurality of sheets, and the metal foil is laminated on one side or both sides according to the application to be processed into a laminate. Metal-clad laminates are particularly suitable as printed wiring boards.

＜Printed Circuit Board＞

The printed wiring board of the present invention can be obtained by removing part of the metal foil on the surface of the metal foil-clad laminate by etching or the like to form a circuit, thereby forming a circuit on the surface of the resin film or prepreg. By containing the thermosetting composition, the printed wiring board is excellent in dielectric properties such as dielectric constant and dielectric loss tangent, moldability, and heat resistance.

In addition, the thermosetting composition can be used for molding, lamination, adhesives, composite materials such as copper clad laminates, and the like. In particular, when an isocyanate or an epoxy is used alone or in combination, typical examples include a prepreg obtained by semi-curing a resin, and a laminate obtained by curing the prepreg. Moreover, when an epoxy body is used, the application example to a semiconductor sealing material is mentioned typically.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example at all.

＜Synthesis of Dialkyl Peroxide＞

<Preparation Example 1>

To a 500 mL round bottom flask, α-methylstyrene (purity 99.2%, 42.54 g, 0.36 mol), isopropanol (17.02 g), HCl (purity 35.0%, 24.94 g, 0.68 mol) were added and stirred. The above solution was heated to 35°C, and 1,1,3,3-tetramethylbutyl hydroperoxide (purity 90.0%, 32.17 g, 0.40 mol) was added dropwise. After completion of the dropwise addition, the mixture was stirred for 1.5 hours, and the obtained solution was washed with a 3% NaOH aqueous solution and then washed with water. Then, dehydration was performed using sodium sulfate and magnesium sulfate to obtain a mixture containing 1,1,3,3-tetramethylbutylcumyl peroxide in which R1 in the above general formula (1) represents a neopentyl group. Then, solvent removal was performed at 50° C./1 hour using a vacuum pump to obtain 1,1,3,3-tetramethylbutylcumyl peroxide (79.3 g, purity 90.3%, yield 92.3%).

In addition, the structure of the above-mentioned dialkyl peroxide was identified by 1H-NMR measurement using an AVANCEN NMR spectrometer (manufactured by BRUCKER Scientific Technology Co. Ltd.), 13C-NMR measurement, and TOFMS (manufactured by JEOL LTD.). In addition, the purity was calculated by the simple planimetric method in GC (GC-2014 series manufactured by Shimadzu Corporation).

¹ _{H - NMR} ( _{CDCl 3} , internal standard TMS) _; CH ₃ ) ₂ CH ₂ C(CH ₃ ) ₃ ), 1.50(2H,m,-OC(CH ₃ ) ₂ CH ₂ C(CH ₃ ) ₃ ), 1.57(6H,s,C ₅ H ₆ -C( CH ₃ ) ₂ -O-), 7.20-7.29 (1H, m, aroma.H), 7.29-7.32 (2H, m, aroma.H), 7.44-7.47 (2H, m, aroma.H), molecular weight: 264

<Preparation Example 2>

It was the same except that the 1,1,3,3-tetramethylbutyl hydroperoxide in Preparation Example 1 was changed to tert-hexyl hydroperoxide. Tert-hexylcumyl peroxide (63.1 g, purity 94.3%, yield 69.9%) was obtained.

¹ _H - _NMR ( _{CDCl 3} , internal standard TMS _{) ;} CH ₃ ) ₂ CH ₂ CH ₂ CH ₃ ), 1.26-1.36(2H,m, -OC(CH ₃ ) ₂ CH ₂ CH ₂ CH ₃ ), 1.46-1.59(8H,m, -C(CH ₃ ) ₂ -OOC(CH ₃ ) ₂ CH ₂ CH ₂ CH ₃ ), 7.20-7.25(1H,m,arom.H), 7.29-7.37(2H,m,arom.H), 7.42-7.47(2H,m,arom.H) .H), molecular weight: 236

<Preparation Example 3>

It was the same except that the 1,1,3,3-tetramethylbutyl hydroperoxide in Preparation Example 1 was changed to tert-amyl hydroperoxide. Tert-amylcumyl peroxide (64.2 g, purity 89.0%, yield 89.4%) was obtained.

¹ _H -NMR ( _{CDCl 3 ,} internal standard TMS _{) ;} ) ₂ CH ₂ CH ₃ ), 1.46-1.55(6H,m, -C(CH ₃ ) ₂ -OOC(CH ₃ ) ₂ CH ₂ CH ₃ ), 7.20-7.26(1H,m,arom.H), 7.30 -7.36 (2H, m, aroma.H), 7.41-7.47 (2H, m, aroma.H), molecular weight: 224

<Examples 1-10, Comparative Examples 1-6>

＜Evaluation of fluidity＞

Each component (parts by mass) shown in Table 1 or Table 2 was diluted with toluene and blended at a concentration of 50% by mass, and 3.5 g of the toluene solubilized product of the composition thus obtained was added to a 6 ml screw thread placed in a vial and placed in a constant temperature bath at 60°C. The time until the composition did not move at all when it was turned upside down was defined as gelation time, and evaluated according to the following criteria. ⊚: No gelation after 300 hours or more. ◯: Gelation occurred after 190 hours or more and within 300 hours. ×: Gelation occurred within 190 hours.

＜Preparation of cured product and evaluation of dielectric properties＞

Each component (parts by mass) shown in Table 1 or Table 2 was diluted with toluene and blended so that the concentration was 50% by mass, and 6 g of the toluene solution of the composition thus obtained was added to an aluminum pan, After drying at 400 Pa and 60° C. for 2 hours using a vacuum dryer (EYELA VACUUM OVEN VOS-3LSD), solvent drying was further performed at 80° C. for 2 hours. The resulting powder was molded at 130° C. using a Hand Press (manufactured by TOYOSEIKI Co., Ltd.), and cured at 200° C. to obtain a cured product (film, 16 cm circular, 60 μm thick) ). The dielectric constant and dielectric loss tangent at 1 GHz of the obtained cured product were measured by the method based on IPC-TM-650-2.5.5.9, and evaluated according to the following criteria. ◎: The dielectric constant (Dk) is less than 2.85, and the dielectric loss tangent (Df) is less than 0.0039. ○: The dielectric constant (Dk) is not less than 2.85 and not more than 3.06, and the dielectric loss tangent (Df) is not less than 0.0039 and not more than 0.005. ×: When the dielectric constant (Dk) and dielectric loss tangent (Df) are other than the above-mentioned ◎ or ○.

＜Evaluation of heat resistance＞

Using the DSC measurement method, the glass transition temperature of the cured product was measured according to IPC-TM-650-2.4.25 at a heating rate of 10° C./min, and evaluated according to the following criteria. ⊚: The glass transition temperature (° C.) is 175 or higher. ◯: The glass transition temperature (° C.) is 165 or higher. ×: The glass transition temperature (° C.) is less than 165.

Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Thermosetting composition [parts by mass] Polyphenylene ether OPE-2St 2200 100 100 100 100 100 100 100 100 OPE-2St 1200 100 SA 9000 100 The dialkyl peroxide represented by general formula (1) 1,1,3,3-Tetramethylbutylcumyl peroxide 1 5 5 5 1 1 tert-Hexylcumyl peroxide 1 1 1 tert-amyl cumyl peroxide 1 Bis-(2-tert-butylperoxyisopropyl)benzene tert-Butylcumyl peroxide Tertiary alkyl hydroperoxide (parts by mass relative to 100 parts by mass of dialkyl peroxide) 1,1,3,3-Tetramethylbutyl hydroperoxide 0.003 (0.3) 0.015 (0.3) 0.015 (0.3) 0.015 (0.3) 0.0002 (0.02) 0.04 (4) tert-Hexyl Hydroperoxide 0.003 (0.3) 0.003 (0.3) 0.003 (0.3) tert-Amyl Hydroperoxide 0.003 (0.3) tert-butyl hydroperoxide (parts by mass relative to 100 parts by mass of dialkyl peroxide) 1,4-hydroquinone multifunctional monomer TAIC 10 1,4-divinylbenzene 10 physical properties Dielectric properties Dielectric constant (Dk) 2.84 2.95 2.98 3.05 2.90 3.02 2.98 2.99 2.91 2.85 Dielectric loss positive (Df) 0.00389 0.00398 0.00485 0.00491 0.00391 0.00432 0.00471 0.00399 0.00483 0.00477 evaluate ◎ ○ ○ ○ ○ ○ ○ ○ ○ ○ heat resistance Glass transition temperature (°C) 169 173 176 175 171 171 173 174 174 168 evaluate ○ ○ ◎ ◎ ○ ○ ○ ○ ○ ○ fluidity Gelation time (h) 210 200 190 195 195 250 200 200 230 200 evaluate ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Table 2 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative Example 5 Comparative Example 6 Thermosetting composition [parts by mass] Polyphenylene ether OPE-2St 2200 100 100 100 100 100 100 OPE-2St 1200 SA 9000 The dialkyl peroxide represented by general formula (1) 1,1,3,3-Tetramethylbutylcumyl peroxide 1 1 tert-Hexylcumyl peroxide 1 tert-amyl cumyl peroxide Bis-(2-tert-butylperoxyisopropyl)benzene 1 tert-Butylcumyl peroxide 1.5 Tertiary alkyl hydroperoxide (parts by mass relative to 100 parts by mass of dialkyl peroxide) 1,1,3,3-Tetramethylbutyl hydroperoxide 0.2 (20) tert-Hexyl Hydroperoxide 0.0002 (0.01) tert-Amyl Hydroperoxide tert-butyl hydroperoxide 0.003 (0.3) 0.0045 (0.3) (parts by mass relative to 100 parts by mass of dialkyl peroxide) 1,4-hydroquinone 0.003 (0.3) multifunctional monomer TAIC 1,4-divinylbenzene physical properties Dielectric properties Dielectric constant (Dk) 2.40 3.10 3.01 3.08 2.82 3.14 Dielectric loss tangent (Df) 0.00388 0.00535 0.00515 0.00512 0.00473 0.00522 evaluate ◎ x x x ○ x heat resistance Glass transition temperature (°C) 157 174 173 160 170 159 evaluate x ○ ○ x ○ x fluidity Gelation time (h) Not gelled 170 160 205 135 230 evaluate ◎ x x ○ x ○

In Tables 1 and 2, OPE-2St 2200 is a polyphenylene ether having an average of 2 ethylenically unsaturated double bonds at the molecular terminal (number average molecular weight 2200), manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.); OPE-2St 1200 is a polyphenylene ether having an average of 2 ethylenically unsaturated double bonds at the molecular end (the number average molecular weight is 1200), manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.); SA9000 is a polyphenylene ether having an average of 2 ethylenically unsaturated double bonds at the molecular end Double-bonded polyphenylene ether (number-average molecular weight is 2756), manufactured by SABIC Innovative Plastics); 1,1,3,3-tetramethylbutylcumyl peroxide is Preparation Example 1 (purity 90.8%); tert-hexyl cumyl peroxide is Preparation 2 (purity 94.3%); tert-amyl cumyl peroxide is Preparation 3 (purity 89.0%); two-(2-tert-butyl peroxyiso Propyl)benzene is manufactured by NOF Corporation (purity 99.9%); tert-butyl cumyl peroxide is manufactured by NOF Corporation (purity 90.2%); 1,1,3,3-tetramethylbutyl hydroperoxide Manufactured for NOF Corporation (purity 90.3%); tert-hexyl hydroperoxide is manufactured by NOF Corporation (purity 85.2%); tert-amyl hydroperoxide is manufactured by United Initiators (purity 84.8%); tert-butyl hydroperoxide is manufactured by NOF Corporation Manufactured (purity 68.9%); 1,4-hydroquinone is manufactured by Tokyo Chemical Industry Co., Ltd. (purity 99.9%); TAIC (Triallyl Isocyanurate, triallyl isocyanurate) is Tokyo Chemical Industry Co. , Ltd. (purity: 96.0%); 1,4-divinylbenzene is manufactured by Tokyo Chemical Industry Co., Ltd. (purity: 98.0%).

For Examples 1 to 10, polyphenylene ether cured products capable of maintaining the fluidity of the thermosetting composition and exhibiting excellent physical properties were obtained.

In Comparative Example 1, a test was performed without adding a dialkyl peroxide, and as a result, the heat resistance of the cured polyphenylene ether did not appear.

For Comparative Examples 2 and 3, bis-(2-tert-butylperoxycumyl)benzene and tert-butylcumyl peroxide were used respectively. As a result, although the heat resistance of the cured polyphenylene ether was high, the intermediate The electrical characteristics are low, and the fluidity of the thermosetting composition is lost in a short time.

For Comparative Example 4, more than 10 parts by mass of tertiary alkyl hydroperoxide was added relative to the dialkyl peroxide. As a result, although the gelation of the thermosetting composition could be suppressed, the heat resistance of the cured polyphenylene ether and dielectric properties are not excellent.

In Comparative Example 5, less than 0.02 parts by mass of tertiary alkyl hydroperoxide was added to the dialkyl peroxide. As a result, although the cured polyphenylene ether was excellent in heat resistance and dielectric properties, it lost Flowability of thermosetting compositions.

In Comparative Example 6, 1,4-benzoquinone, which functions as a radical scavenger, was added to the thermosetting composition instead of tert-alkyl hydroperoxide, and gelation was suppressed, but the physical properties did not increase .

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Claims (7)

A thermosetting composition, which is a thermosetting composition containing polyphenylene ether and an organic peroxide, wherein, the polyphenylene ether has an ethylenically unsaturated double bond at the molecular end; the organic peroxide is represented by the general formula (1) For the dialkyl peroxide and tertiary alkyl hydroperoxide represented, the tertiary alkyl hydroperoxide is not less than 0.02 parts by mass and not more than 10 parts by mass with respect to 100 parts by mass of the dialkyl peroxide, [ Chemical formula 1]

In formula (1), R ₁ is an alkyl group having 2 to 8 carbon atoms. The thermosetting composition according to claim 1, wherein the thermosetting composition contains a multifunctional monomer. The thermosetting composition according to Claim 1 or Claim 2, wherein the ethylenically unsaturated double bond is at least one selected from the group consisting of (meth)acryl and vinylbenzyl. A resin film formed from the thermosetting composition described in any one of Claims 1-3. A prepreg, which is formed by impregnating or coating the thermosetting composition described in any one of claims 1 to 3 on a fibrous substrate. A metal foil-clad laminate, which is formed by laminating the resin film described in Claim 4 or the prepreg described in Claim 5 and metal foil. A printed circuit board is formed by removing part of the metal foil from the metal foil-clad laminate described in claim 6.