JP2017075270A - Prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prepreg capable of realizing low Dk.SOLUTION: The prepreg comprises a polyphenylene ether resin composition comprising a polyphenylene ether and a crosslinked curing agent, and a filler with a dielectric constant of 3.5 or less. The polyphenylene ether is represented by general formula (1) and has a number average molecular weight of 1000-7000. In general formula (1), X is an aryl group, (Y)is a polyphenylene ether portion, R, R, and Rindependently represent a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group, m is an integer of 1-100, n is an integer of 1-6, and q is an integer of 1-4.SELECTED DRAWING: None

Description

  The present invention relates to a prepreg. In particular, it is related with the filler which comprises a prepreg.

  In recent years, the speed and capacity of data communication used in information communication has been rapidly increased. Therefore, in the above electronic devices, printed wiring boards that satisfy both high frequency characteristics and multilayer wiring are required.

  A printed wiring board used for information communication is required to have a low dielectric constant (low Dk) and a low dielectric loss tangent (low Df) in order to reduce signal propagation delay and transmission loss. In order to realize these requirements, a resin material containing polyphenylene ether is used as an insulating layer between wirings that are multilayered in a printed wiring board. Polyphenylene ether is a compound that has excellent electrical characteristics (low dielectric constant and low dielectric loss tangent) and is expected to be effective in increasing transmission speed and reducing transmission loss. Attempts have been made to apply this prepreg laminate using polyphenylene ether to a printed wiring board in order to improve the performance and the multilayer structure of the printed wiring board.

  In addition, with the increase in performance and multilayering of printed wiring boards, laminated board materials used for printed wiring boards are required to have a low thermal expansion coefficient and high toughness while maintaining a low dielectric constant. In order to satisfy these requirements, for example, in Patent Document 1 and Patent Document 2, a prepreg using an inorganic filler such as silica as a filler is used.

JP-T-2006-516297 International Publication No. 2009/041137

  However, it has been found that the prepregs shown in Patent Document 1 and Patent Document 2 are limited in lowering the Dk due to the material used for the filler, particularly in the dielectric constant (Dk) characteristic value.

  This invention is made | formed in view of such a subject, and it aims at providing the prepreg which can implement | achieve low Dk.

A prepreg according to an embodiment of the present invention includes a polyphenylene ether resin composition containing polyphenylene ether and a cross-linking curing agent, and a filler having a dielectric constant of 3.5 or less. The polyphenylene ether is represented by the general formula (1).

And the number average molecular weight is 1000 to 7000. In the general formula (1), X represents an aryl group, (Y) _m represents a polyphenylene ether moiety, and R ¹ , R ² , and R ³ are each represented by Independently, it represents a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group, m represents an integer of 1 to 100, n represents an integer of 1 to 6, and q represents an integer of 1 to 4.

  Further, the filler may include at least one of a hollow filler and a fluororesin filler.

  A prepreg according to an embodiment of the present invention includes an epoxy compound having a number average molecular weight of 1000 or less and not containing a halogen atom having at least two epoxy groups in one molecule, a polyphenylene ether having a number average molecular weight of 5000 or less, and cyanic acid. A polyphenylene ether resin composition having a resin varnish containing an ester compound, an epoxy compound, a polyphenylene ether and a curing catalyst for promoting a reaction of a cyanate ester compound as a curing agent, and a halogen flame retardant; and a dielectric constant of 3.5 The following fillers are included.

  Further, the filler may include at least one of a hollow filler and a fluororesin filler.

  According to the present invention, it is possible to provide a prepreg capable of realizing low Dk.

<Embodiment 1>
Hereinafter, the prepreg according to the present invention will be described in detail. However, the prepreg of the present invention is not construed as being limited to the description of the following embodiments and examples.

[Configuration of prepreg]
The prepreg according to Embodiment 1 of the present invention includes a resin composition containing polyphenylene ether and a crosslinking curing agent, a base material, and a filler having a dielectric constant of 3.5 or less.

(Polyphenylene ether)
The polyphenylene ether contained in the resin composition of the present invention is represented by the above general formula (1), and those having a number average molecular weight of 1000 or more and 7000 or less can be used.

In the above general formula (1), X represents an aryl group, (Y) _m represents a polyphenylene ether moiety, and R ^{1 to} R ³ each represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. In general formula (1), n is an integer from 1 to 6, and q is an integer from 1 to 4. Here, preferably, n is an integer of 1 or more and 4 or less, more preferably, n is 1 or 2, and ideally n is 1. Preferably, q is an integer of 1 or more and 3 or less, more preferably q is 1 or 2, and ideally q is 1.

(Aryl group)
As the aryl group in the general formula (1), an aromatic hydrocarbon group can be used. Specifically, a phenyl group, a biphenyl group, an indenyl group, and a naphthyl group can be used as the aryl group, and an aryl group is preferably used. Here, the aryl group includes a diphenyl ether group in which the aryl group is bonded with an oxygen atom, a benzophenone group bonded with a carbonyl group, or the like, a 2,2-diphenylpropane group bonded with an alkylene group, or the like. But you can. Further, the aryl group, alkyl group (preferably a C ₁ -C ₆ alkyl group, particularly methyl group), an alkenyl group, an alkynyl group or a halogen atom, may be substituted by common substituent. However, since the “aryl group” is substituted on the polyphenylene ether moiety through an oxygen atom, the number of general substituents depends on the number of polyphenylene ether moieties.

(Polyphenylene ether part)
The polyphenylene ether moiety in the general formula (1) is represented by the following general formula (2) and consists of phenyloxy repeating units. Here, the phenyl group may be substituted with a general substituent.

In the above general formula (2), R ^{4 to} R ⁷ each represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an alkenylcarbonyl group. In General formula (2), m shows the integer of 1-100. Here, the value of m is adjusted so that the number average molecular weight of the polyphenylene ether of the general formula (1) is 1000 or more and 7000 or less. That is, m is not a fixed value but may be a variable within a certain range such that the number average molecular weight of the whole polyphenylene ether contained in the polyphenylene ether resin composition is 1000 or more and 7000 or less.

  Here, when the number average molecular weight of polyphenylene ether exceeds 7000, the fluidity at the time of shaping | molding falls and multilayer shaping | molding will become difficult. On the other hand, if the number average molecular weight of the polyphenylene ether is less than 1000, the original excellent dielectric properties and heat resistance of the polyphenylene ether resin may not be obtained. In order to obtain more excellent fluidity, heat resistance, and dielectric properties, the number average molecular weight of the polyphenylene ether is preferably 1200 or more and 5000 or less. More preferably, the polyphenylene ether has a number average molecular weight of 1500 or more and 4500 or less.

  The polyphenylene ether having the number average molecular weight described above has very good compatibility when blended with a crosslinking type curing agent. In other words, the lower the number average molecular weight of polyphenylene ether, the higher the compatibility with the mixture. Therefore, viscosity increase due to phase separation hardly occurs, and volatilization of the low molecular weight cross-linking curing agent is suppressed. As a result, the embedding property of the polyphenylene ether resin composition into a via hole or the like can be improved.

  As the alkyl group, alkenyl group, and alkynyl group in the general formula (2), those similar to the alkyl group, alkenyl group, and alkynyl group in the general formula (1) described below can be used. As the alkenylcarbonyl group of the polyphenylene ether moiety, a carbonyl group substituted with the above alkenyl group can be used. Specifically, an acryloyl group or a methacryloyl group can be used.

Here, the polyphenylene ether moiety in the general formula (2) is a vinyl group, a 2-propylene group (allyl group), a methacryloyl group, an acryloyl group, a 2-propyne group (propargyl group) or the like as the substituents R ^{4 to} R ⁷ . It may have an unsaturated hydrocarbon-containing group. By providing the unsaturated hydrocarbon-containing group in the substituents R ^{4 to} R ⁷ of the polyphenylene ether portion, it is possible to obtain a more remarkable effect of the crosslinkable curing agent.

  The polyphenylene ether having the above-mentioned group at the terminal has good interaction with the cross-linking curing agent. Therefore, the heat resistance can be improved only by adding a relatively small amount of the cross-linking curing agent, and a low dielectric constant can be realized.

(Alkyl group)
As the alkyl group in the general formula (1) and the general formula (2), a saturated hydrocarbon group can be used. Examples of the alkyl group _may be performed using C 1 _{-C 10} alkyl group. Preferably, it is the use of _C 1 -C ₆ alkyl group as the alkyl group described above. More preferably, it may be used a C ₁ -C ₄ alkyl group as the alkyl group described above. More preferably, it may be used to C ₁ -C ₂ alkyl group as the alkyl group described above. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, or a hexyl group can be used as the alkyl group.

(Alkenyl group)
As the alkenyl group in the general formula (1) and the general formula (2), an unsaturated hydrocarbon group having at least one carbon-carbon double bond in the structure can be used. The alkenyl groups described above _may be performed using C 2 _{-C 10} alkenyl group. Preferably, it is the use of _C 2 -C ₆ alkenyl group as an alkenyl group described above. More preferably, it is the use of C ₂ -C ₄ alkenyl group as an alkenyl group described above. Specifically, an ethylene group, a 1-propylene group, a 2-propylene group, an isopropylene group, a butylene group, an isobutylene group, a pentylene group, or a hexylene group can be used as the alkenyl group.

(Alkynyl group)
As the alkynyl group in the general formula (1) and the general formula (2), an unsaturated hydrocarbon group having at least one carbon-carbon triple bond in the structure can be used. As the alkynyl group, a C ₂ -C ₁₀ alkynyl group may be used. Preferably, it is the use of _C 2 -C ₆ alkynyl group as an alkynyl group as described above. More preferably, it is the use of C ₂ -C ₄ alkynyl group as an alkynyl group as described above. Specifically, an ethyn group, a 1-propyne group, a 2-propyne group, an isopropyne group, a butyne group, an isobutyne group, a pentyne group, and a hexyne group can be used as the alkynyl group.

(Crosslinking curing agent)
As the crosslinkable curing agent contained in the resin composition, a curing agent that three-dimensionally crosslinks polyphenylene ether can be used. Specifically, a polyfunctional vinyl compound, a vinyl benzyl ether compound, an allyl ether compound, or a trialkenyl isocyanurate can be used as the crosslinking curing agent. Polyfunctional vinyl compounds include divinylbenzene, divinylnaphthalene, and divinylbiphenyl. Vinyl benzyl ether compounds are synthesized by the reaction of phenol and vinyl benzyl chloride. Allyl ether compounds are synthesized by the reaction of styrene monomer, phenol, and allyl chloride. Trialkenyl isocyanurate has good compatibility, and triallyl isocyanurate (hereinafter referred to as TAIC) or triallyl cyanurate (hereinafter referred to as TAC) can be used.

  In addition to the above materials, (meth) acrylate compounds (methacrylate compounds and acrylate compounds) can be used as the crosslinking curing agent. In particular, the functional (meth) acrylate compound having 3 to 5 functional groups may be contained in an amount of 3 to 20 mass% with respect to the total amount of the resin composition. Trimethylolpropane trimethacrylate (TMPT) or the like can be used as the functional methacrylate compound having 3 to 5 functional groups, while trimethylolpropane triacrylate or the like is used as the functional acrylate compound having 3 to 5 functional groups. Can do. By using the above-mentioned crosslinkable curing agent, the heat resistance of the resin composition can be further improved.

  When the functionality of the (meth) acrylate compound is less than 3 or more than 5, the heat resistance is reduced as compared with a (meth) acrylate compound having a functionality of 3 or more and 5 or less. Moreover, even if it is a (meth) acrylate compound having a functionality of 3 or more and 5 or less, if the content is less than 3% by mass relative to the total amount of the resin composition, the effect of improving the heat resistance of the resin composition is sufficient. Can't get to. On the other hand, when it exceeds 20% by mass, the dielectric properties and moisture resistance are lowered.

  The content ratio of the polyphenylene ether and the crosslinkable curing agent in the resin composition is preferably 30/70 or more and 90/10 or less. Preferably, the content ratio is 50/50 or more and 90/10 or less. More preferably, the content ratio is 60/40 or more and 90/10 or less.

  Here, if the content ratio of the polyphenylene ether is smaller than the lower limit, the rigidity of the entire resin composition is lowered. As a result, it becomes difficult to make the entire resin composition multilayer. On the other hand, when the content ratio of the polyphenylene ether is larger than the upper limit, the heat resistance of the entire resin composition is lowered. By adjusting the content ratio of the polyphenylene ether and the cross-linking curing agent to the above range, good fluidity and compatibility of the resin composition can be obtained. Therefore, the embedding property of the resin composition in a via hole or the like can be improved.

(Base material)
As a base material contained in the prepreg of the present invention, for example, a glass cloth can be used. Moreover, an organic base material can also be used as a base material.

(Other additives)
The resin composition of the present invention includes, as necessary, one or more additives selected from unmodified polyphenylene ether, flame retardant, and reaction initiator, and a filler having a dielectric constant of 3.5 or less (hereinafter referred to as filler). ) Can be added. Moreover, you may add the general additive component of the resin composition used for manufacture of electronic devices, such as a printed wiring board.

(Unmodified polyphenylene ether)
In addition to the above polyphenylene ether, the resin composition of the present invention may contain unmodified polyphenylene ether having a number average molecular weight of 9000 to 18000. By adding unmodified polyphenylene ether, it is possible to control the fluidity of the resin composition and improve the heat resistance. Moreover, precipitation of additional components, such as a filler, can be suppressed in a resin composition. Here, the unmodified polyphenylene ether is a polyphenylene ether having no carbon-carbon unsaturated group in the molecule, and the amount added is 100 parts by mass of the total mass of the polyphenylene ether and the cross-linking curing agent. 3 parts by mass or more and 70 parts by mass or less are preferable.

  Furthermore, in order to improve heat resistance, adhesiveness and dimensional stability, styrene / butadiene block copolymer, styrene / isoprene block copolymer, 1,2-polybutadiene, 1,4-polybutadiene, maleic acid-modified polybutadiene, acrylic acid-modified polybutadiene. And one or more compatibilizers selected from epoxy-modified polybutadiene can be used.

(Filler)
As a result of the inventors' diligent research, it has been found that the factor limiting the reduction in Dk of the prepreg depends on the dielectric constant of the filler itself contained in the prepreg. In addition, as a result of comparing and examining the dielectric constant of the filler and the characteristic value of Dk of the prepreg, when the dielectric constant of the filler is 3.5 or less, the conventional limitation of lowering the Dk of the prepreg is solved, and further lower Dk It became clear that it became possible.

  As described above, the low Dk of the prepreg using the resin composition can be realized by adding a filler having a dielectric constant of 3.5 or less to the resin composition. As the filler having a dielectric constant of 3.5 or less, a filler having a dielectric constant of 3.5 or less such as a hollow filler or a fluororesin filler can be used.

  As the hollow filler, a hollow filler having a porosity of 10% to 50% can be used. Preferably, a hollow filler having a porosity of 15% to 40% can be used. More preferably, a hollow filler having a porosity of 15% or more and 25% or less can be used. In addition, when the porosity of a hollow filler is lower than a minimum, the effect of dielectric constant reduction will become small. Moreover, when the porosity of a hollow filler is higher than an upper limit, a hollow filler will be easy to break.

  As the fluororesin filler, a fluororesin filler having an average particle size of 0.2 μm or more and 1.0 μm or less can be used. Preferably, a fluororesin filler having an average particle size of 0.3 μm or more and 0.9 μm or less can be used. More preferably, a fluororesin filler having an average particle size of 0.4 μm or more and 0.7 μm or less can be used. In addition, when the average particle diameter of a fluororesin filler is smaller than a minimum, the melt viscosity of a prepreg will rise and a void will be generated when a prepreg is laminated | stacked. Moreover, when the average particle diameter of a fluororesin filler is larger than an upper limit, the adhesiveness of an inorganic filler and a fluororesin will deteriorate.

(Flame retardants)
By adding a flame retardant to the resin composition, water resistance, moisture resistance, moisture absorption heat resistance, and glass transition point of a prepreg using the resin composition can be improved. As the flame retardant, a brominated organic compound such as an aromatic bromine compound can be used. Specifically, decabromodiphenylethane, 4,4-dibromobiphenyl, ethylenebistetrabromophthalimide, or the like can be used. Preferably, the brominated organic compound is contained in an amount such that the bromine content is 8% by mass or more and 20% by mass or less based on the total amount of the resin composition.

  When the bromine content is smaller than the lower limit, the flame retardancy of the prepreg is lowered, and the flame retardancy at the UL standard 94V-0 level cannot be maintained. On the other hand, when the bromine content is larger than the upper limit, bromine is easily dissociated when the prepreg is heated, and the heat resistance of the prepreg is lowered.

(Reaction initiator)
By adding a reaction initiator to the resin composition, a more remarkable effect of the cross-linking curing agent can be obtained. As the reaction initiator, any general material can be used as long as it can improve the properties such as heat resistance of the resin composition by promoting the curing of the resin composition at an appropriate temperature and time. Specifically, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne, benzoyl peroxide 3,3 ′, 5,5′-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, azobisisobutyronitrile An oxidizing agent such as can be used. Here, if necessary, a carboxylic acid metal salt or the like may be added to further accelerate the curing reaction.

  As described above, according to the prepreg according to the first embodiment of the present invention, low Dk can be realized by using a filler having a dielectric constant of 3.5 or less as a filler.

[Prepreg production method]
In the prepreg according to the present invention, a filler having a dielectric constant of 3.5 or less can be used as the filler.

  A prepreg is obtained by impregnating a base material with a varnish obtained by adding a solvent to the resin composition. The amount of the varnish impregnated into the substrate is preferably such that the mass ratio of the resin solid content in the prepreg is 35% by mass or more. Since the dielectric constant of the base material is larger than the dielectric constant of the resin, in order to reduce the dielectric constant of the printed wiring board obtained using this prepreg, the resin solid content in the prepreg is determined from the above mass ratio. More is better. The base material impregnated with the varnish can be heated at a temperature of 80 ° C. or higher and 150 ° C. or lower for a period of 1 minute or longer and 10 minutes or shorter. However, the heating conditions of the base material impregnated with the varnish are not limited to the above conditions.

[Method for producing printed wiring board (laminate)]
Here, the manufacturing method of the laminated body using the prepreg produced as mentioned above is demonstrated. First, one or a plurality of prepregs are stacked, and a metal foil such as a copper foil is stacked on both upper and lower surfaces or one surface thereof, and the laminate is heated and pressed. By this molding, a laminate having metal foil on both sides or one side can be produced. A printed wiring board can be obtained by patterning and etching the metal foil of the laminate to form a circuit. Further, a multilayer printed wiring board can be manufactured by stacking a plurality of prepregs with a metal foil on which a circuit is formed sandwiched therebetween, followed by heating and pressing.

The heating and pressing conditions vary depending on the content ratio of the raw material of the resin composition according to the present invention, but generally 170 ° C. or higher and 230 ° C. or lower, pressure 1.0 MPa or higher and 6.0 MPa or lower (10 kg / cm ² or higher and 60 kg). / Cm ² or less) is preferably heated and pressurized for an appropriate time.

  As a metal foil used for the above laminate, the surface roughness (ten-point average roughness: Rz) is 2 μm or less, and the surface on the side where the resin layer is formed by the prepreg (surface on the side in contact with the prepreg) However, it is possible to use a copper foil that has been treated with zinc or a zinc alloy for rust prevention and improved adhesion to the resin layer and further subjected to a coupling treatment with a vinyl group-containing silane coupling agent or the like. Such a copper foil has good adhesion to the resin layer (insulating layer), and a printed wiring board having excellent high frequency characteristics can be obtained. In addition, when processing copper foil with zinc or a zinc alloy, zinc and a zinc alloy can be formed in the surface of copper foil by the plating method.

  Thus, the laminated body and printed wiring board which were obtained can implement | achieve low Dk. In addition, a laminate or a printed wiring board having high moldability, water resistance, moisture resistance, moisture absorption heat resistance, and glass transition point can be obtained.

<Embodiment 2>
Hereinafter, the prepreg according to the present invention will be described in detail. However, the prepreg of the present invention is not construed as being limited to the description of the following embodiments and examples.

[Configuration of prepreg]
The prepreg according to Embodiment 2 of the present invention includes a resin composition comprising a resin varnish having an epoxy compound, a polyphenylene ether, a cyanate ester compound, a curing catalyst, and a halogen flame retardant, a base material, and a dielectric constant of 3.5. The following fillers are included. Here, the epoxy compound has a number average molecular weight of 1000 or less and does not contain a halogen atom having at least two epoxy groups in one molecule. The polyphenylene ether has a number average molecular weight of 5000 or less. The curing catalyst promotes the reaction between the epoxy compound and polyphenylene ether and the cyanate ester compound that is a curing agent.

(Epoxy compound)
As the epoxy compound, a dicyclopentadiene type epoxy compound, a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a phenol novolac type epoxy compound, a naphthalene type epoxy compound, a biphenyl type epoxy compound, or the like can be used. These can be used alone or in combination. Of these, dicyclopentadiene type epoxy compounds, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, and biphenyl type epoxy compounds are particularly preferred because of their good compatibility with polyphenylene ether. In addition, although it is preferable not to contain a halogenated epoxy compound in this resin composition, as long as the effect of this invention is not impaired, you may add as needed.

  It is preferable that the content rate of the epoxy compound in the prepreg of this embodiment is 20 mass% or more and 60 mass% or less with respect to the total amount of the component of an epoxy compound, polyphenylene ether, and a cyanate ester compound. More preferably, the content ratio of the epoxy compound is 30% by mass or more and 50% by mass or less. By making the content rate of an epoxy compound into said range, sufficient heat resistance and the outstanding mechanical characteristic and electrical property can be maintained.

(Polyphenylene ether)
The polyphenylene ether has a number average molecular weight of 5000 or less, preferably 2000 or more and 4000 or less.

  When the number average molecular weight of the polyphenylene ether exceeds 5000, the fluidity is deteriorated and the reactivity with the epoxy group is also lowered. Therefore, it takes a long time for the curing reaction, and it is not taken into the curing system, and unreacted ones increase, the glass transition temperature decreases, and sufficient heat resistance cannot be obtained.

  The content ratio of the polyphenylene ether in the prepreg of the present embodiment is preferably 20% by mass or more and 60% by mass or less with respect to the total amount of components of the epoxy compound, polyphenylene ether, and cyanate ester compound. More preferably, the content of polyphenylene ether is 20% by mass or more and 40% by mass or less. When the content ratio of the polyphenylene ether is within the above range, excellent dielectric properties can be obtained.

(Cyanate ester compound)
As the cyanate ester compound, a compound having two or more cyanate groups in one molecule can be used. Specifically, 2,2-bis (4-cyanatophenyl) propane, bis (3,5-dimethyl-4-cyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) ethane, etc. Alternatively, aromatic cyanate ester compounds such as derivatives thereof can be used. These can be used alone or in combination.

  The cyanate ester compound is a component that acts as a curing agent for the epoxy compound for forming the epoxy resin and forms a rigid skeleton. Therefore, a high glass transition point (Tg) can be obtained. Moreover, since the viscosity is low, the high fluidity of the resin varnish obtained can be maintained.

  The content ratio of the cyanate ester compound in the prepreg of the present embodiment is preferably 20% by mass or more and 60% by mass or less with respect to the total amount of the components of the epoxy compound, polyphenylene ether, and cyanate ester compound. More preferably, the content ratio of the cyanate ester compound is 20% by mass or more and 40% by mass or less. When the content ratio of the cyanate ester compound is in the above range, sufficient heat resistance can be obtained, the impregnation with respect to the substrate is excellent, and crystals can be hardly precipitated even in the resin varnish.

(Curing catalyst)
Examples of curing catalysts include octanoic acid, stearic acid, acetylacetonate, naphthenic acid, organic acid salts such as salicylic acid, organic metal salts such as Zn, Cu, and Fe, tertiary amines such as triethylamine and triethanolamine, 2-ethyl- Imidazoles such as 4-imidazole and 4-methylimidazole can be used. These can be used alone or in combination. Among the above, organic metal salts, particularly zinc octoate is preferable because higher heat resistance can be obtained.

  The content of the curing catalyst in the prepreg of the present embodiment is, for example, 0.005 with respect to the total amount (100 parts by mass) of the components of the epoxy compound, polyphenylene ether, and cyanate ester compound when using an organic metal salt. It can be set to 5 parts by mass or more. For example, when imidazoles are used, the content of the curing catalyst is 0.01 parts by mass or more and 5 parts by mass with respect to the total amount (100 parts by mass) of the components of the epoxy compound, polyphenylene ether, and cyanate ester compound. It can be as follows.

(Halogen flame retardant)
As the halogen-based flame retardant, a halogen-based flame retardant that does not dissolve in a varnish adjusted with a solvent such as toluene can be used. Specifically, as the halogen-based flame retardant, ethylene dipentabromobenzene, ethylene bistetrabromophthalimide, decabromodiphenyl oxide, tetradecabromodiphenoxybenzene, bis (tribromophenoxy) ethane, or the like can be used. Of these, ethylenedipentabromobenzene, ethylenebistetrabromophthalimide, decabromodiphenyl oxide, and tetradecabromodiphenoxybenzene have a melting point of 300 ° C. or higher and high heat resistance, so that the heat resistance of the prepreg is improved. Can do. When a halogen-based flame retardant having a melting point of 300 ° C. or higher and high heat resistance can be used, it is possible to suppress the elimination of halogen at a high temperature, and thus it is possible to suppress a decrease in heat resistance due to decomposition of the cured product.

  The average particle diameter in the dispersed state of the halogen-based flame retardant is 0.1 μm or more and 50 μm or less, and more preferably 1 μm or more and 10 μm or less can sufficiently maintain heat resistance and interlayer insulation. The average particle size can be measured with a particle size distribution meter (SALD-2100) manufactured by Shimadzu Corporation.

  The content ratio of the halogen-based flame retardant in the prepreg of the present embodiment is such that the halogen concentration is 5% by mass or more and 30% by mass or less in the total amount of the resin component (that is, the component excluding the inorganic component) in the obtained cured product. It is preferable to make it contain in a proper ratio.

(Base material)
As a base material contained in the prepreg of the present invention, for example, a glass cloth can be used. Moreover, an organic base material can also be used as a base material.

(Filler)
As described above, the low Dk of the prepreg using the resin composition can be realized by adding a filler having a dielectric constant of 3.5 or less to the resin composition. As the filler having a dielectric constant of 3.5 or less, a filler having a dielectric constant of 3.5 or less such as a hollow filler or a fluororesin filler can be used.

  The content of the filler in the prepreg of the present embodiment is 10 parts by mass or more and 100 parts by mass or less with respect to the total amount (100 parts by mass) of the components of the epoxy compound, polyphenylene ether, and cyanate ester compound. It is good to contain by a ratio. Preferably, the filler content may be 20 to 70 parts by mass. More preferably, the filler content may be 20 to 50 parts by mass. By making the content rate of a filler into said range, dimensional stability can be improved, without reducing fluidity | liquidity and adhesiveness with metal foil.

  The resin composition of this invention may add the general addition component of the resin composition used for manufacture of electronic devices, such as a printed wiring board, other than said filler. For example, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a flame retardant, a dye, a pigment, a lubricant and the like may be added.

[Prepreg production method]
In the present resin composition of the prepreg according to Embodiment 2 of the present invention, the components of the epoxy compound, polyphenylene ether, and cyanate ester compound are all dissolved in the resin varnish. It is not dissolved in the resin varnish but is dispersed. Such a resin varnish is prepared as follows, for example.

  First, a predetermined amount of an epoxy compound and a cyanate ester compound are dissolved in a resin solution of polyphenylene ether. This dissolution may be performed at room temperature or while heating. As an epoxy compound and a cyanate ester compound, the formation of precipitates in the resin varnish can be suppressed by using a material that dissolves in a solvent such as toluene at room temperature.

  Here, when a filler having a dielectric constant of 3.5 or less is added as an additive, it is dispersed until a predetermined dispersion state is obtained using a ball mill, a bead mill, a planetary mixer, a roll mill or the like after the filler is added. A resin varnish is prepared.

  A prepreg can be obtained by impregnating the substrate with the resin varnish obtained as described above and drying it by the same production method as in Embodiment 1. Moreover, a printed wiring board (laminated body) can be obtained by the same manufacturing method as in the first embodiment.

  Below, the prepreg which concerns on Embodiment 1 and Embodiment 2 of this invention is produced, and the result of having evaluated the characteristic value of dielectric constant (Dk) is demonstrated concretely. Example 1 and Example 2 described below correspond to the example of the first embodiment, and Example 3 and Example 4 correspond to the example of the second embodiment.

  First, the polyphenylene ether used in Examples 1 and 2 and Comparative Example 1 will be described.

(Polyphenylene ether (1))
CuBr ₂ 3.88 g (17.4 mmol), N, N′-di-t-butylethylenediamine 0.75 g (4.) in a 12-liter vertical reactor equipped with a stirrer, thermometer, air introduction tube and baffle plate. 4 mmol), 28.04 g (277.6 mmol) of n-butyldimethylamine and 2600 g of toluene, stirred at a reaction temperature of 40 ° C., and dissolved in 2300 g of methanol in advance, 2,2 ′, 3,3 ′, 5,5′-hexamethyl- (1,1′-biphenol) -4,4′-diol 129.3 g (0.48 mol), 2,6-dimethylphenol 233.7 g (1.92 mol), 2,3, 6-trimethylphenol 64.9 g (0.48 mol), N, N'-di-t-butylethylenediamine 0.51 g (2.9 mmol), n-butyldi A mixed gas of 10.90 g (108.0 mmol) of tilamine was added dropwise over 230 minutes while bubbling at a flow rate of 5.2 liters / min with a mixed gas adjusted to an oxygen concentration of 8% by mixing nitrogen and air. And stirring was performed.

  After completion of the dropwise addition, 1500 g of water in which 19.89 g (52.3 mmol) of ethylenediaminetetraacetic acid tetrasodium was dissolved was added to stop the reaction. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1N hydrochloric acid aqueous solution and then with pure water. The obtained solution was concentrated to 50 wt% with an evaporator to obtain 836.5 g of a toluene solution of a bifunctional phenylene ether oligomer (resin “A”). The resin “A” had a number average molecular weight of 986, a weight average molecular weight of 1530, and a hydroxyl group equivalent of 471.

  In a reactor equipped with a stirrer, a thermometer, and a reflux tube, 836.5 g of a toluene solution of resin “A”, vinylbenzyl chloride (trade name CMS-P; manufactured by Seimi Chemical Co., Ltd.) 162.6 g, methylene chloride 1600 g, 12.95 g of benzyldimethylamine, 420 g of pure water, and 178.0 g of a 30.5 wt% NaOH aqueous solution were charged, followed by stirring at a reaction temperature of 40 ° C. After stirring for 24 hours, the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The obtained solution was concentrated with an evaporator, dropped into methanol for solidification, and the solid was collected by filtration and vacuum dried to obtain 503.5 g of “polyphenylene ether (1)”. The number average molecular weight of “polyphenylene ether (1)” was 1187, the weight average molecular weight was 1,675, and the vinyl group equivalent was 590 g / vinyl group.

(Polyphenylene ether (2))
CuBr ₂ (9.36 g, 42.1 mmol) and N, N′-di-t-butylethylenediamine (1.81 g) in a 12-liter vertical reactor equipped with a stirrer, a thermometer, an air introduction tube, and a baffle plate (10. 5 mmol), 67.77 g (671.0 mmol) of n-butyldimethylamine, 2600 g of toluene, stirred at a reaction temperature of 40 ° C., and dissolved in 2300 g of methanol in advance, 2,2 ′, 3,3 ′, 5,5′-hexamethyl- (1,1′-biphenol) -4,4′-diol 129.32 g (0.48 mol), 2,6-dimethylphenol 878.4 g (7.2 mol), N, N ′ -A mixed solution of 1.22 g (7.2 mmol) of di-t-butylethylenediamine and 26.35 g (260.9 mmol) of n-butyldimethylamine A mixed gas adjusted to an oxygen concentration of 8% by mixing nitrogen and air was added dropwise over 230 minutes while bubbling at a flow rate of 5.2 liters / min, followed by stirring.

  After completion of the dropping, 1500 g of water in which 48.06 g (126.4 mmol) of ethylenediaminetetraacetic acid tetrasodium was dissolved was added to stop the reaction. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1N hydrochloric acid aqueous solution and then with pure water. The obtained solution was concentrated to 50 wt% with an evaporator to obtain 1981 g of a toluene solution of a bifunctional phenylene ether oligomer (resin “B”). The resin “B” had a number average molecular weight of 1975, a weight average molecular weight of 3514, and a hydroxyl group equivalent of 990.

  In a reactor equipped with a stirrer, a thermometer, and a reflux tube, 833.4 g of a toluene solution of the resin “B”, 76.7 g of vinylbenzyl chloride (trade name CMS-P; manufactured by Seimi Chemical Co., Ltd.), 1600 g of methylene chloride, 6.2 g of benzyldimethylamine, 199.5 g of pure water, and 83.6 g of a 30.5 wt% NaOH aqueous solution were charged and stirred at a reaction temperature of 40 ° C. After stirring for 24 hours, the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The obtained solution was concentrated with an evaporator, dropped into methanol for solidification, and the solid was collected by filtration and vacuum dried to obtain 450.1 g of “polyphenylene ether (2)”. The number average molecular weight of vinyl “polyphenylene ether (2)” was 2250, the weight average molecular weight was 3920, and the vinyl group equivalent was 1189 g / vinyl group.

  Next, the manufacturing method of the prepreg of Example 1 and Example 2, and the comparative example 1 and the evaluation sample of a dielectric constant is demonstrated.

[Example 1]
70 parts by mass of the above polyphenylene ether (1) was prepared, 100 parts by mass of toluene was added as a solvent, and the mixture was stirred at 80 ° C. for 30 minutes and completely dissolved. 30 parts by mass of “TAIC” manufactured by Nippon Kasei Co., Ltd. as a crosslinkable curing agent and ethylene bis (pentabromophenyl) (Albemarle) as a brominated organic compound as a flame retardant are used for the polyphenylene ether solution thus obtained. 50 parts by mass of “SAYTEX8010 (trade name)” manufactured by Nippon Co., Ltd. and 50 parts by mass of hollow silica having a porosity of about 19% (manufactured by Admatechs Co., Ltd.) as a filler. Here, the dielectric constant of the hollow silica is 3.0. These were diluted with methyl ethyl ketone to a solid content of 65% to obtain a varnish. Since the above flame retardant is a brominated organic compound that is non-reactive with polyphenylene ether and TAIC, the flame retardant was not dissolved in toluene but dispersed in the varnish as the resin composition.

Next, after impregnating the above-mentioned varnish into E glass cloth (IPC No. # 3313) as a base material, it was dried by heating at a temperature of 170 ° C. for 5 minutes to remove the solvent, and the resin content was 55 mass. % Prepreg was obtained. The thickness of the E glass cloth used as the substrate is 80 μm. Eight prepregs thus obtained were stacked, and 18 μm thick copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) was stacked on both upper and lower sides thereof. Vacuum pressing was performed under the molding conditions of a temperature of 210 ° C. and a pressure of 3.0 MPa (30 kg / cm ² ) for 150 minutes to obtain a double-sided copper-clad laminate for a printed wiring board having a thickness of 0.8 mm. The dielectric constant was evaluated using the obtained copper-clad laminate.

(Measuring method)
Using a test piece from which the copper foil of the copper clad laminate having a thickness of 0.8 mm was removed, a dielectric constant of 10 GHz was measured by a cavity resonator perturbation method (Agilent 8722ES, manufactured by Agilent Technologies).

[Example 2]
In Example 2, it replaced with polyphenylene ether (1) used in Example 1, and produced varnish using polyphenylene ether (2). The method for producing the varnish of Example 2 was performed in the same manner as in Example 1. Moreover, as a filler used in Example 2, a fluororesin filler (manufactured by DIC) was used. Here, the average particle diameter of the fluororesin filler is 0.6 μm, and the dielectric constant is 2.5.

[Comparative Example 1]
In Comparative Example 1, which is a comparative example of Example 1 and Example 2 above, conventional spherical synthetic silica (“SC2050” manufactured by Admatechs Co., Ltd.) was used instead of the hollow silica of Example 1 and the fluororesin filler of Example 2. (Trade name) ").

  Table 1 shows configurations and evaluation results of Examples 1 and 2, and Comparative Example 1.

  As shown in Table 1, compared to Comparative Example 1 using conventional spherical synthetic silica as a filler, Example 1 using hollow silica as a base material and Example 2 using a fluororesin filler are smaller. It was confirmed that a Dk value can be obtained. That is, it was confirmed that a Dk value smaller than the conventional one can be obtained by using a filler having a dielectric constant of 3.5 or less as the filler.

  Subsequently, the polyphenylene ether and the epoxy compound used in Examples 3 and 4 and Comparative Example 2 will be described.

(Polyphenylene ether (3))
As the “polyphenylene ether (3)”, polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics) having a hydroxyl group at the end of polyphenylene ether was used. The number average molecular weight of “polyphenylene ether (3)” is 1700.

(Epoxy compound (1))
As the epoxy compound, a dicyclopentadiene type epoxy compound (“Epiclon HP7200 (trade name)” manufactured by DIC) was used. Epicron HP7200 has a number average molecular weight of 550.

(Epoxy compound (2))
As the epoxy compound, a naphthalene skeleton-modified epoxy resin (“Epiclon HP4032D (trade name)” manufactured by DIC) was used. Epicron HP4032D has a number average molecular weight of 280.

  Next, the manufacturing method of the prepreg of Example 3 and Example 4, and the comparative example 2, and the evaluation sample of a dielectric constant is demonstrated.

[Example 3]
30 parts by mass of the above polyphenylene ether (3) was prepared, toluene was added as a solvent, mixed and stirred, and completely dissolved. With respect to the polyphenylene ether solution thus obtained, 45 parts by mass of the above epoxy compound (1) and 2,2-bis (4-cyanatophenyl) propane (Mitsubishi Gas Chemical) as a cyanate ester compound were used. After adding 25 parts by mass of “CA210 (trade name)” manufactured by Co., Ltd., it was stirred for 30 minutes and completely dissolved. Furthermore, 50 parts by mass of the above-mentioned “SAYTEX8010” as a flame retardant and 50 parts by mass of hollow silica (manufactured by Admatechs Co., Ltd.) having a porosity of about 19% as a filler are mixed, and the solid content is made 65% with methyl ethyl ketone Dilution was performed to obtain a varnish. Here, the dielectric constant of the hollow silica is 3.0. In addition, said flame retardant did not melt | dissolve but was disperse | distributed with the average particle diameter of 1 micrometer or more and 10 micrometers or less in the resin varnish.

Next, after applying the above varnish to the E glass cloth (IPC No. # 3313) as a base material, it was dried by heating at a temperature of 170 ° C. for 5 minutes to obtain a prepreg having a resin content of 55% by mass. It was. The thickness of the E glass cloth used as the substrate is 80 μm. Eight prepregs thus obtained were stacked, and 18 μm thick copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) was stacked on both upper and lower sides thereof. Vacuum pressing was performed under conditions of a temperature of 210 ° C., a pressure of 3.0 MPa (30 kg / cm ² ), and 150 minutes to obtain a double-sided copper-clad laminate for a printed wiring board. Next, the dielectric constant of 10 GHz was measured by the cavity resonator perturbation method (Agilent 8722ES, manufactured by Agilent Technologies) using the obtained test piece from which the copper foil of the copper clad laminate having a thickness of 0.8 mm was removed. .

[Example 4]
In Example 4, it replaced with the epoxy compound (1) used in Example 3, and produced the varnish using the epoxy compound (2). The production method of the varnish of Example 4 was the same as that of Example 3. Further, as a filler used in Example 4, a fluororesin filler (manufactured by DIC) was used. Here, the dielectric constant of the fluororesin filler is 2.5.

[Comparative Example 2]
As a comparative example of the above Example 3 and Example 4, in Comparative Example 2, conventional spherical synthetic silica (“SC2050” manufactured by Admatechs Co., Ltd.) was used instead of the hollow silica of Example 3 and the fluororesin filler of Example 4. (Trade name) ").

  Table 2 shows configurations and evaluation results of Examples 3 and 4, and Comparative Example 2.

  As shown in Table 2, it is smaller in Example 3 using hollow silica as a base material and Example 4 using a fluororesin filler as compared with Comparative Example 2 using conventional spherical synthetic silica as a filler. It was confirmed that a Dk value can be obtained. That is, it was confirmed that a Dk value smaller than the conventional one can be obtained by using a filler having a dielectric constant of 3.5 or less as the filler.

  As described above, according to the prepregs according to Examples 1 to 4 of the present invention, a low Dk could be realized by using a filler having a dielectric constant of 3.5 or less as a filler.

Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention.

Claims (4)

A polyphenylene ether resin composition comprising polyphenylene ether and a cross-linking curing agent;
A filler having a dielectric constant of 3.5 or less,
The polyphenylene ether has the general formula (1)

And the number average molecular weight is 1000 to 7000,
In the general formula (1), X represents an aryl group, (Y) _m represents a polyphenylene ether moiety, and R ¹ , R ² , and R ³ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. M represents an integer of 1 to 100, n represents an integer of 1 to 6, and q represents an integer of 1 to 4.   The prepreg according to claim 1, wherein the filler includes at least one of a hollow filler and a fluororesin filler. An epoxy compound having a number average molecular weight of 1000 or less and having at least two epoxy groups in one molecule and containing no halogen atom, a polyphenylene ether having a number average molecular weight of 5000 or less, a cyanate ester compound, the epoxy compound, and the polyphenylene A polyphenylene ether resin composition having a curing catalyst for promoting the reaction between the ether and the cyanate ester compound as a curing agent, and a resin varnish containing a halogen-based flame retardant;
A prepreg comprising a filler having a dielectric constant of 3.5 or less.   The prepreg according to claim 3, wherein the filler includes at least one of a hollow filler and a fluororesin filler.