JP4487590B2 - Resin composition used for production of laminate, prepreg and laminate using the same - Google Patents

Description

  The present invention relates to a laminate which is a material for a multilayer printed board used in an electronic device, a prepreg used for the production of the laminate, and a resin composition used for the production of the prepreg.

  A glass cloth is impregnated with a resin composition containing a polyphenylene ether resin (hereinafter, polyphenylene ether may be referred to as “PPE”), an epoxy resin, and a curing agent, and a prepreg is produced using this. This has been done conventionally. Such a laminate is used in the satellite communication wave region because it has excellent high-frequency characteristics, in particular, it exhibits a constant dielectric constant and dielectric loss tangent over a wide temperature range and humidity range, and a low dielectric loss tangent. It is suitable for the X band (10 GHz) region.

  In the above resin composition, as the PPE resin, a modified phenol compound obtained by condensing a low molecular weight PPE and a phenol compound by redistributing a high molecular weight PPE and a phenol compound in the presence of a radical initiator is used. There is a technique for manufacturing a laminated board. In this laminate, it is considered that the solvent resistance is improved by reacting the phenolic hydroxyl group present at the terminal of the modified phenolic compound with the epoxy group in the epoxy resin to form a crosslinked structure.

  In addition, an inorganic filler is added to the resin composition used for the production of a laminated board, which is a multilayer printed board material, in order to impart various characteristics. For example, PPE resin has a disadvantage that it has a high coefficient of thermal expansion compared to other polymer materials and impairs the dimensional stability of the laminate, and therefore silica that can reduce the coefficient of thermal expansion is added. Alternatively, talc may be added to suppress resin flow during pressure curing.

  However, PPE resins and epoxy resins, which are organic polymers, have a low affinity with inorganic fillers, and thus there is a problem in that the adhesive state cannot be maintained in the laminate. Therefore, in order to solve such a problem, surface treatment of the inorganic filler has been performed.

  For example, Patent Document 1 discloses a composition containing a thermosetting polyphenylene ether resin and silica that is an inorganic filler, and the surface of the silica has a specific silane cup having a methacryloxy group, a glycidoxy group, or a vinyl group at the terminal. What has been treated with a ring agent is disclosed. And it describes that the metal foil and film with resin manufactured with this composition have a low coefficient of thermal expansion and excellent smoothness.

  Patent Document 2 includes an epoxy resin, a modified phenolic compound (a product obtained by reacting a high molecular weight PPE and a phenolic compound in the presence of a radical initiator) and a curing agent, and further a silane such as γ-aminopropyltrimethoxysilane. A composition comprising talc surface-treated with a coupling agent is disclosed.

However, a resin composition containing a PPE resin, an epoxy resin and a curing agent has poor adhesion to an inorganic filler, and there is a problem that when a laminate is produced using this, the resin may dissociate from the inorganic filler. there were. Further, the moisture absorption resistance and electric corrosion resistance of the resin are not satisfactory, and further improvement of these characteristics has been desired.
JP 2001-81305 A (Claim 1) JP 2000-212256 A (Claim 1)

  Under the circumstances described above, the problem to be solved by the present invention is a resin composition containing an inorganic filler in addition to a PPE resin, an epoxy resin and a curing agent, and has high adhesion between the resin and the inorganic filler, and The object is to provide a material that also has excellent moisture absorption resistance and electric corrosion resistance. Another object of the present invention is to provide a prepreg and a laminate using the resin composition. These prepreg and laminate have the properties that the resin composition enjoys, such as the adhesion between the resin and the inorganic filler.

In order to solve the above-mentioned problems, the present inventors have intensively studied surface treatment agents for inorganic fillers in order to improve the adhesion between the resin and the inorganic filler, that is, the affinity. As a result, surprisingly, it has been found that if the inorganic filler is surface-treated with a silane coupling agent in which an ammonium base is substituted on an alkyl derivative group bonded to a silicon atom, the adhesion between the two can be improved. The present invention has been completed.

That is, the resin composition of the present invention is a resin composition used for the production of a laminate, and includes (A) a polyphenylene ether resin, (B) an epoxy resin, (C) a curing agent, and (D) an inorganic filler. only including, the inorganic filler, characterized in that it is one which is surface treated with a silane coupling agent having an ammonium salt as a substituent on the alkyl derivative group bonded to the silicon atom.

  As the resin composition, it is preferable that the polyphenylene ether resin is a modified phenol compound obtained by redistributing a high molecular weight polyphenylene ether and a phenol compound in the presence of a radical initiator. This is because the modified phenolic compound has the ability to react with the epoxy resin, and the polyphenylene ether structure in the structure is involved in the crosslinking between the resins, so that the adhesive strength of the laminate can be increased.

As the silane coupling agent, N- (3-trimethoxysilylpropyl) -N- [2- (4-vinylbenzylamino) ethyl] ammonium chloride (N-β- (N-vinylbenzylaminoethyl) -γ -Aminopropyltrimethoxysilane hydrochloride) is preferred. This is because the adhesive strength of the laminate can be increased as compared with a coupling agent having an amino group in a free state as a substituent on the alkyl derivative group , and this effect is demonstrated by the examples described later. Because.

  As said inorganic filler, what was surface-treated by 0.5-2 mass parts said silane coupling agent with respect to 100 mass parts of inorganic fillers before the said surface treatment is preferable. This is because if the amount of the silane coupling agent is within such a range, deterioration of heat resistance and a decrease in the adhesion between the resin and the inorganic filler can be reliably suppressed.

  The prepreg of the present invention is characterized in that the above resin composition is impregnated into a base material and semi-cured, and the laminate of the present invention is obtained by subjecting the prepreg and copper foil to heat-pressure molding. It is characterized by being laminated.

  The resin composition of the present invention has not only the original property of the PPE resin composition, which is excellent in dielectric properties, but also excellent adhesion between the resin and the inorganic filler, and further has high moisture absorption resistance and electric corrosion resistance. Therefore, the resin composition according to the present invention and the prepreg impregnated with the resin composition are useful as a material for producing a laminated board. And this laminated board enjoys the characteristic of the resin composition of this invention as it is, and is very useful industrially especially as what is used in a high frequency area | region.

  Hereinafter, embodiments of the present invention and effects thereof will be described.

(A) Polyphenylene ether resin (PPE resin)
The PPE resin that can be used in the present invention is a homopolymer or copolymer of a phenol derivative, or a copolymer of a phenol derivative and another monomer as long as it has a so-called polyphenylene ether as a main skeleton. Those used as electronic device component materials can be used without particular limitation. Examples of such PPE resins include poly (2,6-dimethyl-1,4-phenylene ether).

  In the present invention, it is also preferable to use a modified phenol compound obtained by redistributing a high molecular weight PPE and a phenol compound in the presence of a radical initiator. Such a modified phenolic compound has a structure in which one end of a high molecular weight PPE that has been appropriately cut and reduced in molecular weight is substituted with a phenolic compound.

  As this modified phenol compound, those having a number average molecular weight of 1000 to 3000 are preferably used. This is because if the number average molecular weight is less than 1000, the heat resistance of the laminate may be lowered. On the other hand, if it exceeds 3000, the melt viscosity of the resin increases when the resin impregnated in the substrate is semi-cured to the B stage. As a result, the peel strength of the metal foil of the laminate, the solder heat resistance, and the plating penetration performance may be hindered.

  As the “high molecular weight PPE resin” used for the production of the modified phenolic compound, those having a number average molecular weight of 10,000 to 30,000 are preferably used. A typical example is poly (2,6-dimethyl-1,4-phenylene oxide). Such a high molecular weight PPE resin can be produced, for example, by the synthesis method disclosed in the specification of USP 4,059,568.

  As the phenol compound used in the redistribution reaction of the high molecular weight PPE, polyfunctional phenols having two or more phenolic hydroxyl groups in the molecule, such as polyphenols bisphenol A, phenol novolak, and cresol novolak, are preferable. Examples of radical initiators include benzoyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butyl peroxide. Peroxides such as oxyhexine-3, 2,5-dimethyl-2,5-di-tert-butylperoxyhexane, α, α'-bis (tert-butylperoxy-m-isopropyl) benzene It is done. Further, as a initiator, a trade name “Biscumyl” (one minute half temperature: 330 ° C.) manufactured by Nippon Oil & Fats Co., Ltd., which is not a peroxide but a commercially available initiator, can be used.

  The synthetic reaction of the modified phenol compound is carried out by mixing and heating a high molecular weight PPE, a phenol compound and a radical initiator in a solvent or without a solvent. As a catalyst, cobalt naphthenate or the like may be added. The solvent used here is not particularly limited as long as it can dissolve these compounds appropriately and does not inhibit the reaction. For example, an aromatic hydrocarbon solvent such as benzene or toluene can be used. The reaction temperature and the reaction time depend on the number average molecular weight of the target PPE, but are reacted at 60 to 100 ° C. for 30 minutes to 6 hours, for example. These reaction conditions may be determined by preliminary experiments. After completion of the reaction, the solvent may be used as it is by simply distilling off the solvent under reduced pressure, but it may be roughly purified by adding a solvent such as methanol having low solubility to PPE to the reaction system and precipitating the target product.

(B) Epoxy resin Generally known epoxy resins can be used as the epoxy resin. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, isocyanurate type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, biphenyl Type epoxy resin, polyfunctional epoxy resin, and the like. In the present invention, these epoxy resins can be used alone or in combination of two or more. Furthermore, flame retardant epoxy resins obtained by brominating these resins can also be used.

(C) Curing agent As the curing agent, those conventionally used can be used, and there is no particular limitation as long as it can be used as a curing agent for the epoxy resin. Examples thereof include amine-based curing agents such as 1 amine and secondary amine, phenol-based curing agents such as bisphenol A and bisphenol F, and acid anhydride-based curing agents. In the present invention, these curing agents can be used alone or in combination of two or more.

(D) Inorganic filler The kind of the inorganic filler added to the resin composition of the present invention may be selected according to the property to be imparted to the resin composition, but the surface treatment with a silane coupling agent is required. Therefore, it is necessary to have at least a hydroxyl group on the surface. Examples of such inorganic fillers include silica, talc, kaolin, and clay (aluminum silicate).

  The shape of the inorganic filler is not particularly limited, and may be spherical or crushed as long as it is silica, for example. The blending amount is preferably 60 to 150 parts by mass with respect to 100 parts by mass of the resin component (total of additives excluding PPE resin, epoxy resin, curing agent and other inorganic fillers). When the amount of the inorganic filler is less than the above, sufficient rigidity necessary to form a laminate as a high-rigidity material may not be obtained, while when more than the above, There is a possibility that dregs and voids may occur during molding, and the heat resistance may decrease.

In the present invention, the inorganic filler is surface-treated using a silane coupling agent having an ammonium salt as a substituent on the alkyl derivative group bonded to the silicon atom . Here, “having an ammonium salt as a substituent on the alkyl derivative group bonded to the silicon atom ” means that an amino group (1st to 3rd class amino group) exists on the alkyl derivative group of the silane coupling agent. In this state, the amino group becomes a cation (such as —NH ₃ ⁺ ) by an acid or the like and forms a salt with a counter anion. Examples of such counter anions include nitrate ions and sulfate ions in addition to halogen ions such as chloride ions and bromide ions.

  When the inorganic filler is surface-treated with a silane coupling agent, the following reaction occurs on at least a part of the inorganic filler surface.

  That is, the structure of the silane coupling agent is such that at least two alkoxy groups and at least one alkyl derivative group are substituted on the silicon atom, and when the silane coupling agent is added to water, the alkoxy group undergoes hydrolysis and silanol groups. Is formed and further self-condensed to become an oligomer. Dehydration occurs between the silanol groups of the oligomer and the hydroxyl groups present on the surface of the inorganic filler, and at least a part of the surface of the inorganic filler is covered with the silane compound. Therefore, the ammonium salt as a substituent in the present invention needs to be present on the alkyl derivative group, not on the alkoxy group of the silane coupling agent. If present on the alkoxy group, the ammonium salt and the coupling agent are separated by hydrolysis, and the effect of the ammonium salt is not exhibited. In addition, since the solvent used for the surface treatment is mainly only a neutral protic solvent such as methanol or water, the ammonium salt present in the structure of the silane coupling agent is coupled to the surface of the inorganic filler. It will be present as it is in the structure of the agent.

As the “silane coupling agent having an ammonium salt as a substituent on the alkyl derivative group bonded to the silicon atom ” used in the present invention, N- (3-trimethoxysilylpropyl) -N- [2- ( 4-vinylbenzylamino) ethyl] ammonium chloride (N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride), N- (2-benzylaminoethyl) -N- (3 -Trimethoxysilylpropyl) -N- (4-vinylbenzyl) ammonium chloride (N-β- (N-benzylaminoethyl) -N-vinylbenzyl-γ-aminopropyltrimethoxysilane hydrochloride), N- ( 3-Trimethoxysilylpropyl) -N- (4-vinylbenzyl) -N- [2- (4-vinylbenzylamino) ethyl] ammonium chloride (N-β- (N-vinylbenzylaminoethyl) -N-vinyl Benzyl-γ-aminopropyltrimethoxysilane N- (2-Benzhydrylaminoethyl) -N- (3-trimethoxysilylpropyl) ammonium chloride (N-β- (N-benzhydrylaminoethyl) -γ-aminopropyltrimethoxy Silane / hydrochloride), octadecyldimethyl (3- (trimethoxysilyl) propyl) ammonium chloride, and the like.

  In the surface treatment, it is preferable to add 0.5 to 2 parts by mass of the silane coupling agent with respect to 100 parts by mass of the inorganic filler before the surface treatment. If the amount of the silane coupling agent is less than the above, sufficient adhesion between the resin and the inorganic filler may not be obtained during the molding of the laminate, whereas if more than the above, after the molding The heat resistance of the laminate may be reduced.

  The surface treatment method of the inorganic filler is not particularly limited, but is preferably a wet method because the surface needs to be uniformly treated. Specifically, an inorganic filler is added to the silane coupling agent solution to form a slurry or soak, and then dried by heating.

(E) Other additives Other additives may be added to the resin composition of the present invention in order to improve the properties of the resin. For example, an imidazole curing accelerator or the like may be added as necessary for the curing reaction of the epoxy resin.

  The resin composition used in the present invention comprises a polyphenylene ether resin, an epoxy resin, a curing agent, and other additives with an inorganic filler subjected to the above surface treatment, and other components as necessary. It can be prepared by mixing uniformly with a mill or the like.

  The prepreg of the present invention can be produced by impregnating a glass cloth with the above resin composition, then drying by heating, and then semi-curing the resin composition in the glass cloth to a B-stage state. . The heating conditions for drying and semi-curing can be appropriately set depending on the composition of the resin composition, etc., and can be, for example, 150 to 170 ° C. for 4 to 7 minutes.

For impregnating the glass composition with the resin composition, a known method can be employed. For example, the above resin composition may be dissolved in an organic solvent to prepare a resin varnish, and this resin varnish may be impregnated into a glass cloth. Examples of the organic solvent used here include aromatic hydrocarbons such as toluene, xylene, and benzene; ketones; alcohols. These organic solvents can be used alone or in combination of two or more. Moreover, what is necessary is just to set the resin content rate of the prepreg of this invention suitably according to the thickness of a glass cloth, and its intended purpose, For example, it can be 45 to 65% .
The electrical laminate (substrate material) of the present invention is formed using the above prepreg and metal foil such as copper foil. One or a plurality of prepregs can be used, and after a metal foil is stacked on one or both sides of this prepreg, the resin composition of the prepreg is cured by heating and pressing to form an insulating layer. In addition, a single-sided or double-sided metal foil-clad laminate can be formed by integrating the metal foil and the insulating layer by curing the resin composition.

  The heating and pressing conditions in the above-described lamination molding can be appropriately set depending on the thickness of the laminated board to be produced, the type of the resin composition of the prepreg, etc., for example, a temperature of 190 to 210 ° C., a pressure of 3.5 to It can be 4.0 Pa and time 120-150 minutes. The laminated board thus obtained has excellent adhesion between the resin and the inorganic filler, has higher moisture absorption resistance and electric corrosion resistance, and can be suitably used even in the high frequency region. .

  Hereinafter, the present invention will be described in more detail by way of examples, but the scope of the present invention is not limited thereto.

Example 1 Production of Resin Composition, Prepreg and Laminate A resin composition was prepared with the formulation shown in Table 1. First, 30 parts by mass (hereinafter referred to as “parts”) of high molecular weight polyphenylene ether (number average molecular weight: about 15000, manufactured by Nippon GE Plastics) and 1.2 parts of bisphenol A are heated and melted and mixed. A modified phenolic compound having a number average molecular weight of about 2000 was prepared by blending 5 parts of benzoyl peroxide (a radical initiator manufactured by NOF Corporation).

Separately, N- (3-trimethoxysilylpropyl) -N- [2- (4-vinylbenzylamino) ethyl] ammonium chloride is a silane coupling agent having the above alkyl derivative group substituted with an ammonium base. (N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane / hydrochloride) (manufactured by Shin-Etsu Silicone, “Silane Coupling Agent A” in Table 1) was dissolved in methanol to obtain a solid content of 1 A treatment solution of mass% is prepared, and silica (particle shape: almost spherical, average particle size: 0.5 μm, manufactured by Admatex) is immersed and stirred in this treatment solution for 1 hour, and then dried at 120 ° C. for 1 hour. As a result, a surface-treated silica was obtained.

  In addition to the modified phenolic compound (polyphenylene ether resin) and surface-treated silica (inorganic filler), 48 parts brominated bisphenol A type epoxy resin (“EPPN501H” manufactured by Nippon Kayaku) as an epoxy resin, 18 parts Phenol novolac type epoxy resin ("EPN1182" manufactured by Asahi Ciba), 1 part diaminodiphenylmethane ("Ecure" manufactured by Yuka Shell) as a curing agent, 0.3 part 2-ethyl-4-methyl as a curing accelerator -It was set as the resin composition using imidazole (made by Shikoku Chemicals).

  100 parts of this resin composition was dissolved in 90 parts of toluene to prepare a resin varnish, and this resin varnish was impregnated into a glass cloth. The glass cloth was heated and dried, and the resin composition was semi-cured to form a prepreg having a resin content of 50%.

  Next, 8 sheets of the above prepregs are stacked, and a copper foil having a thickness of 18 μm is stacked on both outer sides of these prepregs, and this is heated and pressed under conditions of a temperature of 200 ° C., a pressure of 3.5 MPa, and a time of 120 minutes. Thus, a double-sided copper-clad laminate having a thickness of 0.8 mm was manufactured.

Examples 2-9
The prepreg and both surfaces were the same as in Example 1 except that the inorganic filler used was a surface treated with the amount of silica and / or silane coupling agent A changed as shown in Table 1. A copper clad laminate was produced.

Comparative Example 1
A prepreg and a double-sided copper-clad laminate were produced in the same manner as in Example 1 except that 100 parts of silica not subjected to surface treatment was used as the inorganic filler.

Comparative Example 2
N-phenyl-3-aminopropyltrimethoxysilane (in Table 1, “silane coupling agent B”) which is a silane coupling agent in which an ammonium base is not substituted on an alkyl derivative group bonded to a silicon atom. A prepreg and a double-sided copper-clad laminate were produced in the same manner as in Example 1 except that 30 parts of silica subjected to the same surface treatment as in Example 1 was used.

Test Example About the double-sided copper-clad laminate produced in Examples 1 to 9 and Comparative Examples 1 and 2, hygroscopicity, resin-inorganic filler adhesion (by SEM cross section observation), HAST test, moldability, flexural modulus And the heat resistance was evaluated.

  For hygroscopicity, the copper foil on the surface of the obtained double-sided copper-clad laminate is removed by etching, cut into 5 cm squares, and measured for weight increase values before and after being placed in a kettle with a temperature of 121 ° C. and humidity of 100% for 300 hours This value was evaluated as ○ when the value was 0.8% or less, Δ when the value was 0.8 to 1.0%, and × when the value was 1% or more.

  Resin-inorganic filler adhesion was obtained by removing the copper foil on the surface of the obtained double-sided copper-clad laminate by etching and treating it with a kettle at a temperature of 121 ° C. and a humidity of 100% for 24 hours and not treating it. The fracture surface is observed with a scanning electron microscope (SEM). The one where the inorganic filler does not fall out regardless of whether it is treated or not. The inorganic filler is covered with resin without treatment. There is no dropout of the emphasis agent, but with treatment, the inorganic filler is not covered with resin, and the dropout from the resin is seen as △, regardless of whether treatment is present, the inorganic filler is covered with resin. The case where the falling off from the resin was observed was evaluated as x.

  In the HAST test, through holes having a hole diameter of 0.3 m and a hole interval of 0.25 mm were opened in the obtained double-sided copper-clad laminate, and 3.5 V was applied between the through holes in an atmosphere at a temperature of 130 ° C. and a humidity of 85%. A voltage was applied, and a value of 1 μA or less for 200 hours was evaluated as “◯”, a value of 100 to 200 hours as “Δ”, and a durability of only 100 hours or less as “×”.

  Formability is obtained by removing the copper foil on the surface of the obtained double-sided copper-clad laminate by etching, observing the surface of the laminate and the presence or absence of voids in the cross section of the laminate. The case where there was a scum or a void was evaluated as x.

Evaluation of flexural modulus conducted in compliance with JIS K6911, ○ those values at 300 ° C. of 300 kgf / mm ² or more were evaluated as × those 300 kgf / mm ² or less.

  For heat resistance, the obtained double-sided copper-clad laminate was cut into 5 cm square and placed in an oven at 265 ° C. for 1 hour, and then the presence or absence of swelling on the copper foil and the inner layer was observed. Some were evaluated as x. The results are shown in Table 1.

According to the above results, the laminate (Comparative Example 1) produced without surface treatment of the inorganic filler and a free amino group as a substituent instead of an ammonium salt on the alkyl derivative group bonded to the silicon atom. In the laminated board manufactured using the inorganic filler surface-treated with the silane coupling agent (Comparative Example 2), the adhesion between the inorganic filler and the resin was inferior, and the moisture absorption resistance and the electric corrosion resistance were not sufficient.

On the other hand, as an inorganic filler, the laminate of the present invention produced using a surface treated with a silane coupling agent having an ammonium salt as a substituent on an alkyl derivative group bonded to a silicon atom (Examples 1 to 9) proved that the inorganic filler and the resin were sufficiently adhered even when observed with a scanning electron microscope, and were excellent in moisture absorption resistance and electric corrosion resistance. Therefore, it was revealed that the laminate of the present invention can sufficiently withstand practical use particularly in a high frequency region.

Claims (6)

A resin composition used for the production of a laminate,
(A) a polyphenylene ether resin, (B) an epoxy resin, saw-containing (C) a curing agent, and (D) an inorganic filler, the inorganic filler, the substituents on the alkyl derivative group bonded to the silicon atom A resin composition characterized by being surface-treated with a silane coupling agent having an ammonium salt.   The resin composition according to claim 1, wherein the polyphenylene ether resin is a modified phenol compound obtained by redistributing a high molecular weight polyphenylene ether and a phenol compound in the presence of a radical initiator.   The resin composition according to claim 1 or 2, wherein N- (3-trimethoxysilylpropyl) -N- [2- (4-vinylbenzylamino) ethyl] ammonium chloride is used as the silane coupling agent.   The surface treatment with 0.5-2 mass parts of the said silane coupling agent is carried out with respect to 100 mass parts of said inorganic fillers before the said surface treatment of the said inorganic filler. The resin composition described in 1.   A prepreg obtained by impregnating a base material with the resin composition according to claim 1 and semi-curing the base material. A laminate comprising the prepreg according to claim 5 and a copper foil laminated by heating and pressing.