TWI777919B - Prepregs, Prepregs with Metal Foils, Laminates, Metal-Clad Laminates, and Printed Circuit Boards - Google Patents

Abstract

The present invention provides a prepreg impregnated with a resin composition, wherein a first phase of the resin composition and a second phase serving as an island phase form a phase-separated structure, the average domain size of the island phase is 1 μm to 10 μm, and the The resin composition contains (C) a filler, wherein the first phase contains (A) an acrylic polymer, and the second phase contains (B) a thermosetting resin.

Description

Prepregs, prepregs with metal foils, laminates, metal-clad laminates and printed circuit board

The present invention relates to a prepreg, a prepreg with metal foil, a laminate, a metal-clad laminate and a printed circuit board.

With the rapid spread of information electronic equipment, the miniaturization and thinning of the electronic equipment are gradually progressing, and the printed circuit board mounted therein is also required to be increased in density and function.

Since the thickness of the glass cloth used as the base material is made thinner, for example, the thickness is 30 μm or less, the density of the printed circuit board can be more preferably achieved. Prepreg. As a result, although the density of printed circuit boards has been gradually increased, it has been difficult to ensure sufficient heat resistance, insulation reliability, and adhesion between wiring layers and insulating layers in the printed circuit boards.

Heat resistance, electrical insulation, long-term reliability, adhesiveness, and the like are required for wiring board materials used for such high-performance printed circuit boards. Moreover, as one of these high-performance printed circuit boards, for example, a flexible wiring board material is required, and the flexible wiring board material is required to have low elasticity in addition to the above-mentioned properties.

Further, in the printed circuit board on which the ceramic parts are mounted, there is a problem of the reliability of the connection of the parts, and this problem occurs due to the difference in thermal expansion coefficient between the ceramic parts and the printed circuit board, and external impact. As a solution to this problem, for example, stress relaxation is performed from the printed circuit board side.

As a wiring board material satisfying these requirements, there has been proposed, for example, a resin composition prepared by blending a thermosetting resin with a high molecular acrylic polymer obtained by copolymerizing a crosslinkable functional group. Acrylic polymers are acrylonitrile-butadiene-based resins, carboxyl-containing acrylonitrile-butadiene-based resins, and the like (for example, see Patent Documents 1 to 3).

[Prior Art Literature]

(patent literature)

Patent Document 1: Japanese Patent Application Laid-Open No. 8-283535

Patent Document 2: Japanese Patent Laid-Open No. 2002-134907

Patent Document 3: Japanese Patent Laid-Open No. 2002-371190

Polyacrylate epoxy resin is a polyacrylate epoxy resin obtained by mixing a high molecular acrylic polymer (which is obtained by copolymerizing a crosslinkable functional group) and a thermosetting resin. The structure seems to be interconnected and regularly dispersed. In this state, the sea phase of the macromolecular acrylic polymer and the island phase of the epoxy resin will form a phase-separated structure, and the main component of the sea phase is macromolecular propylene Acid-based polymer, the main component of the island phase is polyacrylate epoxy resin. A resin composition that forms a phase-separated structure and contains a high-molecular acrylic polymer and a polyacrylate epoxy resin is expected to have the excellent characteristics of both the high-molecular acrylic polymer and the epoxy resin, but there is no sufficient combination of both. of outstanding characteristics.

High molecular acrylic polymers obtained by copolymerizing crosslinkable functional groups are characterized by low elasticity, high elongation, and easy addition of functional groups. On the other hand, epoxy resins which are thermosetting resins are characterized by high insulation reliability, high heat resistance, high glass transition temperature (Tg), and the like.

When a high molecular acrylic polymer (which is obtained by copolymerizing a crosslinkable functional group) and an epoxy resin (thermosetting resin) are uniformly mixed with each other to have a structure that is nearly compatible in appearance, the Epoxy resin will be dispersed in the sea phase mesh of macromolecular acrylic polymer in nanometer size, so it will be biased towards the characteristics of macromolecular acrylic polymer, and cannot fully display the high insulation reliability of epoxy resin , high heat resistance, and high Tg. In addition, the surface area of the high-molecular acrylic polymer with relatively weak adhesion strength to the metal foil increases, and the adhesion strength between the insulating layer and the metal foil decreases.

On the other hand, in the phase-separated structure, when the characteristics of the island phase are high, the characteristics of the island phase of the epoxy resin will be biased, and the adhesion strength with the metal foil will be improved, but the polymer cannot be fully expressed. Low elasticity and flexibility of acrylic polymers.

In addition, the introduction of filler components for the purpose of imparting strength and heat resistance is currently being attempted, but it is difficult to achieve a balance due to aggregation and deposition of components, high elasticity of the resin composition, and reduction in heat resistance. In other words, it is difficult to form an insulating layer that sufficiently satisfies insulating reliability, high heat resistance, flexibility, low elasticity, and the like.

An object of the present invention is to provide a prepreg, a metal foil-attached prepreg, a laminate, a metal-clad laminate and a printed circuit board, the prepreg having low elasticity, insulation reliability, heat resistance and compatibility with the metal foil The adhesion between them is excellent.

The present invention relates to the following matters.

(1) a prepreg impregnated with a resin composition, a first phase of the resin composition forming a phase-separated structure with a second phase as an island phase, and the average domain size of the island phase is 1 μm to 10 μm, and The resin composition contains (C) a filler, wherein the first phase contains (A) an acrylic polymer, and the second phase contains (B) a thermosetting resin.

(2) The prepreg according to (1), wherein the (A) acrylic acid is the total amount of the (A) acrylic polymer and the (B) thermosetting resin as 100 parts by mass. The compounding amount of the system polymer is 10 to 70 parts by mass.

(3) The prepreg according to (1) or (2), wherein the resin composition contains (C-1) the coupling-treated filler as the aforementioned (C) filler.

(4) The prepreg described in any one of (1) to (3), wherein the resin composition contains (C-2) an uncoupling filler as the (C) filler.

(5) The prepreg according to any one of (1) to (4), wherein the (B) thermosetting resin includes (B-1) epoxy resin and (B-2) phenol resin.

(6) The prepreg according to (5), wherein the epoxy resin (B-1) contains an epoxy resin having two or more epoxy groups in one molecule.

(7) The prepreg according to (5) or (6), wherein the epoxy resin (B-1) has a weight average molecular weight of 200 to 1,000.

(8) The prepreg according to any one of (5) to (7), wherein the epoxy equivalent of the epoxy resin (B-1) is 150 to 500.

(9) The prepreg according to any one of (1) to (8), wherein the (A) acrylic polymer has a weight average molecular weight of 10,000 to 1,500,000.

(10) The prepreg according to any one of (5) to (9), wherein the (B-2) phenol resin contains a phenol resin having two or more hydroxyl groups in one molecule.

(11) The prepreg according to any one of (1) to (10), which contains silicon oxide as the (C) filler.

(12) The prepreg according to any one of (1) to (11), wherein the volume average particle diameter of the filler (C-2) is 1.0 μm to 3.5 μm

(13) A metal foil-attached prepreg, which is obtained by laminating the prepreg described in any one of (1) to (12) and a metal foil.

(14) A laminate having a plurality of the prepregs according to any one of (1) to (12).

(15) A metal-clad laminate comprising the laminate described in (14) further including a metal foil.

(16) A printed circuit board obtained by further adding a circuit to the laminate described in (14).

According to the present invention, it is possible to provide a prepreg, a metal foil with resin, and a printed circuit board, which are excellent in low elasticity, insulation reliability, heat resistance, and adhesion to the metal foil.

FIG. 1 is a model diagram showing a case where the phase-separated structure of the resin composition is a continuous spherical structure.

FIG. 2 is a model diagram showing a case where the phase-separated structure of the resin composition is a sea-island structure.

FIG. 3 is a model diagram showing a case where the phase separation structure of the resin composition is a composite dispersed phase structure.

Fig. 4 is a model diagram showing a case where the phase separation structure of the resin composition is a co-continuous phase structure.

Fig. 5 is an electron microscope photograph showing a cross-sectional structure as an example of the resin composition having a sea-island structure obtained in the present invention.

Fig. 6 is an electron microscope photograph showing a cross-sectional structure as an example of the resin composition having a composite dispersed phase structure obtained in the present invention.

[Preferred form for carrying out the invention]

Hereinafter, an embodiment of the present invention will be described in detail, but the present invention is not limited to the following embodiment.

(prepreg)

A prepreg according to an embodiment of the present invention is characterized in that a resin composition is impregnated, a first phase of the resin composition and a second phase serving as island phases form a phase-separated structure, and the average domain size of the island phases is 1 μm to 10 μm, and the resin composition contains (C) filler (hereinafter referred to as “(C) component”), the first phase contains (A) acrylic polymer (hereinafter referred to as “(A) component”), The second phase contains (B) a thermosetting resin (hereinafter referred to as "component (B)").

Regarding the reason why the component (A) does not form the island phase but forms the sea phase, we think the reason is as follows: In the component (A) with a large molecular weight and many entanglements, when the component (B) is phase-separated, the component (A) ) component in order to become an island phase, it is necessary to cut off the intertwined or cross-linked network, and it is not easy to become an island phase.

[resin composition] [acrylic polymer: (A) component]

The component (A) is an acrylic polymer, usually a copolymer containing an alkyl (meth)acrylate as a monomer. The copolymer is preferably an acrylic polymer obtained by copolymerizing a crosslinkable functional group. Such a copolymer is generally produced by copolymerizing an alkyl (meth)acrylate and a comonomer having a crosslinkable functional group. The comonomer having a cross-linkable functional group is not particularly limited as long as it is a compound capable of copolymerizing with alkyl (meth)acrylate; as the cross-linkable functional group, it is preferable to have an epoxy group, Glycidyl groups are preferred. As a comonomer having a crosslinkable functional group, glycidyl (meth)acrylate is preferable. In the alkyl (meth)acrylate, the alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, and the alkyl group may have a substituent. As a substituent of an alkyl group, an alicyclic group, a glycidyl group, a C1-C6 alkyl group which has a hydroxyl group, a nitrogen-containing cyclic group, etc. are mentioned, for example.

Examples of alkyl (meth)acrylates include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isobutyl acrylate, ethylene glycol monoacrylate Methyl ether acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, isobornyl acrylate, acrylamide, isodecyl acrylate, octadecyl acrylate, lauryl acrylate, acrylic acid Allyl Ester, N-Vinyl Pyrrolidone Acrylate, Methyl Methacrylate, Ethyl Methacrylate, Propyl Methacrylate, Butyl Methacrylate, Hexyl Methacrylate, 2-Ethyl Methacrylate Hexyl ester, isobutyl methacrylate, ethylene glycol monomethyl ether methacrylate, cyclohexyl methacrylate, methyl methacrylate 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, isobornyl methacrylate, methacrylamide, isodecyl methacrylate, octadecyl methacrylate, lauryl methacrylate , Allyl methacrylate, N-vinylpyrrolidone methacrylate, acrylonitrile, etc.

When the component (A) has an epoxy group, the epoxy group value is preferably 2 equivalents/kg to 18 equivalents/kg, and preferably 2 equivalents/kg to 8 equivalents/kg. When the epoxy group value is 2 equivalents/kg or more, the glass transition temperature of the cured product can be suppressed from falling, and the heat resistance of the substrate can be sufficiently ensured. When the epoxy group value is 18 equivalents/kg or less, the storage elastic modulus is not high. is too large and tends to maintain the dimensional stability of the substrate. When copolymerizing glycidyl (meth)acrylate and another monomer that can be copolymerized therewith, the epoxy group value of the component (A) can be adjusted by appropriately adjusting the copolymerization ratio. Usually, with respect to 100 parts by mass of glycidyl (meth)acrylate, the ratio of other monomers is set to 5 parts by mass to 15 parts by mass, that is, an epoxy group value of 2 equivalents/kg to 18 equivalents/kg can be obtained The high molecular acrylic polymer.

As a commercially available product of the component (A) having an epoxy group, for example, "HTR-860" (manufactured by Nagase ChemteX Co., Ltd., trade name, epoxy group value 3.1), "KH-CT-865" ( manufactured by Hitachi Chemical Co., Ltd., trade name, epoxy value 3.0), "HAN5-M90S" (manufactured by Negami Kogyo Co., Ltd., trade name, epoxy value 2.2). From the viewpoint of improving elongation and improving low elasticity, the weight average molecular weight of component (A) is preferably 10,000 to 1,500,000, more preferably 50,000 to 1,500,000, and 300,000~1,500,000 is better, 300,000~1,100,000 is especially good. When the weight-average molecular weight of the component (A) is 1,500,000 or less, it tends to be easily dissolved in a solvent and easy to handle. In addition, when the weight average molecular weight of the (A) component is 1,500,000 or less, there is a tendency that a phase-separated structure having a co-continuous phase having a large domain is not easily formed after the (B) component is prepared, and high insulation reliability is likely to be exhibited. , High heat resistance, high adhesion tendency to metal foil. When the weight average molecular weight of the (A) component is 10,000 or more, the low elasticity of the (A) component tends to be easily expressed.

(A) Component can combine 2 or more types from which weight average molecular weight differs.

The above-mentioned weight average molecular weight is a value measured by gel permeation chromatography (GPC) analysis, and means a value converted to standard polystyrene. GPC analysis can be performed using tetrahydrofuran (THF) as a solvent.

In addition, in order to obtain sufficient characteristics in an accelerated test of insulation reliability such as a pressure cooker bias test (PCBT), the alkali metal ion concentration of the component (A) is preferably 500 ppm or less, more preferably 200 ppm or less, and more preferably 100 ppm or less. good.

Generally, (A) component is obtained by radically polymerizing a monomer using a radical polymerization initiator which can generate|occur|produce a radical. As the radical polymerization initiator, for example, azobisisobutyronitrile (AIBN), tertiary butyl perbenzoate, benzyl peroxide, lauryl peroxide, potassium persulfate, etc. Sulfate, cumene hydroxide, tertiary butyl hydrogen Peroxide, dicumenyl peroxide, bis(tertiary butyl) peroxide, 2,2'-azobis-2,4-dimethylvaleronitrile, tertiary butyl perisobutyrate , tert-butyl pertrimethylacetate, hydrogen peroxide/ferrous salt, persulfate/sodium bisulfite, cumene hydroperoxide/ferrous salt, benzyl peroxide/dimethyl Aniline etc. As a radical polymerization initiator, it may be used alone or in combination of two or more.

In the resin composition of the embodiment of the present invention, when the total amount of the (A) component and the (B) component is 100 parts by mass, the blending amount of the (A) component is preferably 10 to 70 parts by mass. If the compounding quantity of (A) component is less than 10 mass parts, there exists a tendency which the excellent characteristic of (A) component, ie, low elasticity, will not be effectively expressed. Moreover, when the compounding quantity of (A) component exceeds 70 mass parts, there exists a tendency which the favorable adhesive strength with a metal foil cannot be acquired, or a flame retardance tends to fall.

In addition, in particular, from the viewpoint of making it low in elasticity, in 100 parts by mass of the total amount of the (A) component and the (B) component, the compounding amount of the (A) component is preferably 15 parts by mass or more, and 20 parts by mass. The above is preferable, and 30 parts by mass or more is more preferable.

Moreover, from the viewpoint of obtaining good adhesion strength with metal foil in particular, in 100 parts by mass of the total amount of (A) component and (B) component, the compounding amount of (A) component is 60 parts by mass or less More preferably, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less.

[thermosetting resin: (B) component]

As the component (B) used in the present invention, a compound having a phase-separated structure after being cured in combination with the component (A) is suitably selected. as (B) The components are not particularly limited, and examples thereof include epoxy resins, cyanate ester resins, bismaleimide resins, addition polymers of bismaleimide resins and diamines, phenol resins, and resols. Varnish (resol) resin, isocyanate resin, triallyl isocyanurate resin, triallyl cyanurate resin, vinyl group-containing polyolefin compound, and the like. Among these, an epoxy resin or a cyanate resin is preferable in consideration of the balance of properties such as heat resistance and insulating properties.

Component (B) When the resin composition of the embodiment of the present invention is cured, a resin composite having a phase-separated structure can be formed, and the component (B) is preferably a resin composition comprising: (B-1) Epoxy resins having two or more epoxy groups in one molecule (hereinafter referred to as "(B-1)" components); and (B-2) phenol resins having two or more hydroxyl groups in one molecule (hereinafter referred to as "(B-2)" component).

<Epoxy resin having two or more epoxy groups in one molecule: (B-1) component>

The component (B) preferably contains the component (B-1).

The weight average molecular weight of the component (B-1) is preferably 200 to 1,000, and more preferably 300 to 900. When the weight average molecular weight is 200 or more, a phase-separated structure tends to be formed with the component (A), and when the weight average molecular weight is 1,000 or less, a phase-separated structure having a small second phase tends to be easily formed. And there is a tendency to easily show low elasticity.

The epoxy equivalent of the component (B-1) is preferably 150 to 500, more preferably 150 to 450, and more preferably 150 to 300. If the epoxy ring When the oxygen equivalent is within the above range, the average domain size of the second phase tends not to be too large.

As the component (B-1), a known thing can be used, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, phenol Novolak epoxy resin, cresol novolak epoxy resin, bisphenol A novolak epoxy resin, phosphorus-containing epoxy resin, epoxy resin containing naphthalene skeleton, epoxy resin containing aralkyl skeleton , Phenol biphenyl aralkyl type epoxy resin, phenol salicyl novolac type epoxy resin, phenol salicyl novolac type epoxy resin substituted by lower alkyl, epoxy resin containing dicyclopentadiene skeleton, Multifunctional glycidyl amine epoxy resin, multifunctional alicyclic epoxy resin, tetrabromobisphenol A epoxy resin, etc. One or more of these can be used.

As a commercial item of the component (B-1), for example, a phenol novolak type epoxy resin "N770" (manufactured by DIC Co., Ltd., trade name), and a tetrabromobisphenol A type epoxy resin "EPICLON 153" are mentioned. (manufactured by DIC Co., Ltd., trade name), biphenyl aralkyl type epoxy resin "NC-3000H" (manufactured by Nippon Kayaku Co., Ltd., trade name), bisphenol A type epoxy resin "Epikote 1001" ( Mitsubishi Chemical Corporation, trade name), phosphorus-containing epoxy resin "ZX-1548" (Todo Chemical Co., Ltd., trade name), cresol novolak epoxy resin "EPICLON N-660" (DIC Corporation Co., Ltd., trade name), etc.

<Phenol resin having two or more hydroxyl groups in one molecule: (B-2) component>

From the viewpoint of securing the adhesion strength with the metal foil, the component (B) preferably contains the component (B-2).

As the component (B-2), conventional ones can be used, and examples thereof include aralkyl-type phenol resins, dicyclopentadiene-type phenol resins, salicylic phenol resins, benzaldehyde-type phenol resins, and aralkyl-type phenol resins. Copolymer resins obtained from phenol resins, and novolac-type phenol resins, etc. One or more of these can be used.

It is preferable to use polyhydric phenols, such as a phenol novolak, as a component (B-2) from a viewpoint of low water absorption.

As a commercial item of the component (B-2), for example, cresol novolak resin "KA-1165" (manufactured by DIC Co., Ltd., trade name), and biphenyl novolak resin "MEH-7851" can be mentioned. (Minghe Chemical Co., Ltd., trade name) and so on.

(B-2) The blending ratio of the component is usually determined so that the glass transition temperature increases. For example, when a phenol novolac resin is used as the component (B-2), it is preferable to use 0.5 to 1.5 equivalents of epoxy groups relative to the component (B-1). 0.5 to 1.5 equivalents of the epoxy group relative to the component (B-1) can prevent the decrease in adhesion to the outer layer copper, and also prevent the decrease in glass transition temperature (Tg) and insulating properties.

<(B) Component Hardener>

The resin composition of this invention may contain the hardening|curing agent of (B) component. As a hardening agent of (B) component, a conventional thing can be used. Examples include: amine-based hardeners such as dicyandiamide, diaminodiphenylmethane, and diaminodiphenylene; acid anhydride hardeners such as pyromellitic anhydride, trimellitic anhydride, and benzophenone tetracarboxylic acid ; or a mixture of these, etc.

In the present invention, various combinations of the (B) component and its curing agent can be considered depending on the (A) component used, curing conditions, curing agent, and curing catalyst.

Generally speaking, the phase structure of the resin hardened product is determined by the competitive reaction between the phase separation speed and the crosslinking reaction speed. Taking epoxy resin as an example, it is possible to form a phase-separated structure with an average domain size of about 1 μm to 10 μm by controlling the catalyst species, skeleton structure, etc., and mixing and curing epoxy resins with different characteristics. the island structure.

[filler: (C) component]

The resin composition of the embodiment of the present invention preferably contains one or more kinds of silicon oxides as the component (C). Further, the resin composition of the embodiment of the present invention preferably contains one or more (C-1) coupling-treated fillers (hereinafter referred to as "(C-1) component") as the (C) component. In addition, the tree composition of the embodiment of the present invention preferably contains (C-2) a filler (hereinafter referred to as "(C-2) component") without coupling treatment as the (C) component.

The (C)component used in the present invention preferably contains one or more (C-1) components and one or more (C-2) components. using implemented coupling The treated compound and the (C-2) component not subjected to the coupling treatment can control the filler dispersibility in the resin composition, and can fully express the characteristics of both (A) components and (B) components.

The average particle size of the component (C-1) is preferably 0.1 μm to 1.5 μm, more preferably 0.2 μm to 1.2 μm, and more preferably 0.3 μm to 1.0 μm. When the average particle diameter of the component (C-1) is 0.1 μm or more, the fillers tend to be easily dispersed after varnishing and agglomeration is not likely to occur. When the average particle diameter of the component (C-1) is 1.5 μm or less , the (C) component tends to be less likely to deposit when varnishing.

The average particle size of the component (C-2) is preferably 1.0 μm to 3.5 μm, more preferably 1.2 μm to 3.2 μm, and more preferably 1.4 μm to 3.0 μm. When the average particle diameter of the component (C-2) is 1.0 μm or more, the fillers tend to be easily dispersed and agglomeration does not occur. When the average particle diameter of the component (C-2) is 3.5 μm or less, the progress of the In the case of varnishing, the (C) component does not tend to deposit easily.

Here, the average particle size refers to the particle size at the point corresponding to 50% of the volume when the cumulative power distribution curve obtained from the particle size is obtained by taking the total volume of the particles as 100%, and it can be obtained by using a particle diameter. The particle size distribution measurement apparatus of the diffraction diffraction scattering method etc. is used for measurement.

As (C)component used by this invention, a well-known thing can be used. For the purpose of lowering the thermal expansion coefficient and ensuring flame retardancy, it is preferable to add an inorganic filler. Examples of inorganic fillers include silicon oxide, aluminum oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, calcium oxide, magnesium oxide, aluminum nitride, and boric acid. Aluminum whiskers, boron nitride, silicon carbide, etc. Among them, silicon oxide is preferably used because of its low dielectric constant and low coefficient of linear expansion.

As the silicon oxide used in the present invention, the following various silicon oxides can be used: pulverized silicon oxide obtained by pulverizing various synthetic silicon oxides or silica synthesized by a wet method or a dry method; Various synthetic silicon oxides synthesized by dry method or fused silicon oxides temporarily melted from silica, etc.

In the present invention, the blending ratio of (C) component is preferably 5% by mass to 40% by mass of the solid content of all resin compositions, preferably 10% by mass to 35% by mass of the solid content of all resin compositions, More preferably, it is 15 mass % - 30 mass % of the solid content of all resin compositions. The compounding ratio of (C) component is 40 mass % or less, and the insulating resin does not become brittle and can obtain sufficient high-molecular acrylic polymer obtained by copolymerizing the crosslinkable functional group of (A) component. It has a tendency to have low elasticity and softness. Moreover, when the compounding ratio of (C)component is 5 mass % or more, the linear expansion coefficient will fall and there exists a tendency for sufficient heat resistance to be acquired.

In this specification, the term "solid content" refers to the non-volatile content remaining after removing volatile substances such as solvents, and refers to the remaining components that are not volatilized after drying the resin composition, and are also included in the It is a liquid, maltose and waxy ingredient at room temperature. Here, in this specification, "room temperature" means 25 degreeC.

<Hardening accelerator>

The resin composition may contain a hardening accelerator. Although it does not specifically limit as a hardening accelerator, amines or imidazoles are preferable. Examples of amines include dicyandiamide, diaminodiphenylethane, formamidinyl urea, and the like. Examples of imidazoles include 2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, Trimellitic acid 1-cyanoethyl-2-imidazolium salt, benzimidazole, etc.

The compounding amount of the hardening accelerator can be determined according to the total amount of ethylene oxide rings in the resin composition, and generally, it is set to 0.01 part by mass to 100 parts by mass of the resin solid content of the resin composition. 10 parts by mass is preferable, preferably 0.02 parts by mass to 9.0 parts by mass, and more preferably 0.03 parts by mass to 8.0 parts by mass.

<Other ingredients>

The resin composition of the present invention may contain, for example, a crosslinking agent, a flame retardant, a flow regulator, conductive particles, a coupling agent, a pigment, a leveling agent, an antifoaming agent, an ion trapping agent, an antioxidant, etc., as required. , and can use conventional materials.

<Solvent>

When a prepreg or the like is produced using the resin composition of the present invention, a varnish can be produced in a state in which the components of the resin composition of the present invention are dissolved or dispersed in an organic solvent.

When the resin composition of the present invention is prepared as a varnish, the organic solvent to be used is not particularly limited, and ketone-based, aromatic hydrocarbon-based, ester-based, amide-based, alcohol-based, and the like can be used.

As a ketone type solvent, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. are mentioned, for example.

As an aromatic hydrocarbon type solvent, toluene, xylene, etc. are mentioned, for example.

As an ester type solvent, methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, ethyl acetate etc. are mentioned, for example.

Examples of the amide-based solvent include N-methylpyrrolidone, carboxamide, N-methylformamide, N,N-dimethylacetamide, and the like.

Examples of alcohol-based solvents include methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, triethylene glycol monomethyl ether, triethylene glycol Alcohol monoethyl ether, triethylene glycol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, etc.

These organic solvents may be used alone or in combination of two or more.

[Phase separation structure]

In the present invention, the so-called phase separation structure refers to: sea-island structure, continuous spherical structure, composite dispersed phase structure, and co-continuous phase structure, and the average domain size of the island phase is 1 μm~10 μm, preferably 1 μm~9 μm, and 2μm~8μm is preferred.

If the average domain size of the island phase is less than 1 μm, the good insulation reliability and high heat resistance of the thermosetting resin (B) tend to be difficult to express. In addition, there is a tendency that the surface area of the acrylic polymer having relatively weak adhesive strength with the metal foil becomes large, and good adhesive strength between the insulating layer and the metal foil cannot be obtained.

In addition, when the average domain size of the island phase exceeds 10 μm, the low elasticity of the component (A) tends to be difficult to express.

Here, the average domain size of the island phase is obtained by smoothing the cross section of the resin composition after thermosetting using a microtome, and then using an electron microscope to measure 70 or more of the obtained cross-sectional structures. The maximum width and the minimum width of the island phase were measured, respectively, and the average value was calculated.

Furthermore, regarding the sea-island structure, the continuous spherical structure, the composite dispersed phase structure, and the co-continuous phase structure (also referred to as the continuous phase structure) as the phase-separated structure, it has been described in, for example, "Polymer Alloys", p. 325 (1993) Tokyo. It is described in detail in Chemist, and the continuous spherical structure has been described in detail in, for example, Keizo Yamanaka and Takashi Iniue, POLYMER, Vol. 30, pp. 662 (1989).

Figures 1 to 4 represent model diagrams, showing the continuous spherical structure, the sea-island structure, the composite dispersed phase structure, and the co-continuous phase structure, respectively.

Such a fine phase-separated structure is obtained by controlling the catalyst species of the resin composition, hardening conditions such as reaction temperature, or the compatibility between the components of the resin composition. In order to make phase separation easy to occur, it can be achieved by the following methods, for example: using epoxy resin substituted with alkyl groups to reduce the compatibility with high molecular acrylic polymers, or using the same composition system , increase the hardening temperature, or reduce the hardening rate by selecting the catalyst species.

FIG. 5 shows an electron microscope photograph, which shows a cross-sectional structure of an example of the resin composition having a sea-island structure obtained as described above. As shown in the figure, the resin composition has a sea-island structure, which is composed of an acrylic polymer phase and an epoxy resin-rich phase. In addition, the average domain size of the island phase composed of the epoxy resin is about 1 μm to 10 μm. By having such a phase-separated structure, it is possible to have both of the following excellent characteristics: low elasticity of acrylic polymers; and high insulation reliability, high heat resistance, and metal properties of thermosetting resins. High adhesion between foils.

As described above, the resin composition used in the present invention will form a sea-island structure or a continuous spherical structure when the component (C) is not added thereto, but by adding the component (C), in addition to the sea-island structure or continuous spherical structure In addition, it is also possible to form a fine co-continuous phase structure or a resin insulating layer of a composite dispersed phase structure. FIG. 6 shows an electron microscope photograph showing a cross-sectional structure of an example of an insulating resin having a composite dispersed phase structure.

[Manufacturing method of prepreg]

The prepreg of the present invention can be produced by impregnating the base material with the varnish of the resin composition, and drying it, for example, in the range of 80°C to 180°C.

The base material is not particularly limited as long as it is a base material used in the production of a metal-clad laminate, a printed circuit board, or the like, and a fibrous base material such as a woven fabric and a non-woven fabric is usually used. As the material of the fiber base material, for example, glass, alumina, asbestos, boron, silica alumina glass, silica glass, Inorganic fibers such as Tyranno, silicon carbide, silicon nitride, zirconia, etc.; organic fibers such as aramid, polyetheretherketone, polyetherimide, polyetherimide, carbon, cellulose, etc.; and mixed systems of these. Among these, glass cloth is preferred, glass cloth having a thickness of 100 μm or less is preferred, and glass cloth having a thickness of 50 μm or less is particularly preferred. If the thickness of the glass cloth is 50 μm or less, a printed circuit board that can be bent arbitrarily can be obtained, and dimensional changes due to temperature, moisture absorption, etc. during the process are small, which is preferable.

It is preferable that the organic solvent used in the varnish of the obtained prepreg has volatilized at least 80% by mass. If the organic solvent used in the varnish has volatilized more than 80% by mass, the production method and drying conditions are not limited. During drying, the temperature is, for example, 80°C to 180°C, and the time is appropriately set in consideration of the gelation time of the varnish. . In addition, it is preferable to set the impregnation amount of the varnish so that the solid content of the varnish is 30% by mass to 80% by mass with respect to the total amount of the varnish solid content and the base material.

(Prepreg with metal foil)

The metal foil-attached prepreg of the present invention is preferably formed by laminating the above-mentioned prepreg and metal foil.

The metal foil-attached prepreg of the present invention can be produced by, for example, stacking metal foil on one or both sides of the prepreg of the present invention, and the temperature is usually 130°C to 250°C, preferably It is a temperature in the range of 150°C to 230°C, and is heated and pressurized with a pressure in a range of usually 0.5 MPa to 20 MPa, preferably 1 MPa to 8 MPa. The method of heating and pressing is also not particularly limited, and for example, multi-stage pressing, multi-stage vacuum pressing, continuous molding, autoclave molding machine, and the like can be used.

Moreover, when manufacturing the prepreg with metal foil of this invention, the metal foil used is not specifically limited, For example, copper foil and aluminum foil are generally used. The thickness of the metal foil is not particularly limited, and a metal foil of 1 μm to 200 μm can be used. Others can also be used, such as: using nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. as the intermediate layer and setting 0.5μm~15μm copper layer and 10μm~300μm copper layer on both sides. A composite foil with a 3-layer structure composed of copper layers; or a composite foil with a 2-layer structure composed of aluminum and copper foil.

(laminated board)

The laminate of the present invention preferably has a plurality of the above-mentioned prepregs.

The laminate of the present invention is obtained, for example, by laminating the prepreg of the present invention under heat and pressure. The method of heating and pressing is not particularly limited, and, for example, multi-stage pressing, multi-stage vacuum pressing, continuous molding, autoclave molding machine, and the like can be used.

(metal clad laminate)

It is preferable that the metal-clad laminate of the present invention further includes a metal foil.

The metal-clad laminate of the present invention can be produced by, for example, laminating metal foil on one side or both sides of the laminate of the present invention, and the temperature is usually 130°C to 250°C, preferably 150°C to 230°C. The temperature in the range of °C is usually heated and pressurized with a pressure in the range of 0.5 MPa to 20 MPa, preferably 1 MPa to 8 MPa. The method of heating and pressing is also not particularly limited, and for example, multi-stage pressing, multi-stage vacuum pressing, continuous molding, autoclave molding machine, and the like can be used.

In addition, when manufacturing the metal-clad laminate of the present invention, the metal foil used is not particularly limited, and generally, for example, copper foil and aluminum foil are used. The thickness of the metal foil is not particularly limited, and a metal foil of 1 μm to 200 μm can be used. Others can also be used, such as: using nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. as the intermediate layer and setting 0.5μm~15μm copper layer and 10μm~300μm copper layer on both sides. A composite foil with a 3-layer structure composed of copper layers; or a composite foil with a 2-layer structure composed of aluminum and copper foil.

(Printed Circuit Board)

In the printed circuit board of the present invention, it is preferable that the above-mentioned laminate further has a circuit. The circuit is preferably formed by performing circuit processing on the laminated board of the present invention.

The method for producing the printed circuit board of the present invention is not particularly limited, and it can be produced by applying a circuit to the metal foil of the laminate (metal-clad laminate) of the present invention in which metal foil is provided on one or both sides (Line) processing.

[Example]

Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples. In addition, the numerical value in the following example means mass % unless otherwise indicated.

[Example 1 to Example 13]

Component (A), component (B-1), component (B-2), component (C-1), and component (C-2) were prepared in the amounts shown in Table 1, and these components were After dissolving in methyl ethyl ketone, (D) component and a coupling agent were prepared according to Table 1, and a resin composition varnish with a non-volatile content of 40% was obtained.

[Comparative Example 1 to Comparative Example 10]

(A) component, (B-1) component, (B-2) component, (C-1) component, (C-2) component are prepared in the preparation amounts shown in Table 2, and these components are dissolved In methyl ethyl ketone, (D) component was prepared according to Table 2, and the resin composition varnish of 40% of non-volatile content was obtained.

[Prepreg, metal foil with resin, and metal-clad laminate] (1) Production of prepreg

The varnishes prepared in Examples 1 to 13 and Comparative Examples 1 to 10 were impregnated in glass cloth "1037" (manufactured by Asahi-Schwebel Co., Ltd., trade name) with a thickness of 0.028 mm, and then heated at 140° C. for 10 minutes. , and dried to obtain a prepreg.

(2) Production of copper foil with resin

Using a coater, the varnishes prepared in Examples 1 to 13 and Comparative Examples 1 to 10 were coated on an electrolytic copper foil "YGP-18" (manufactured by Nippon Electron Co., Ltd., trade name) having a thickness of 18 μm. It was molded, and hot-air drying was performed at 140° C. for about 6 minutes to obtain a copper foil with a resin with a coating thickness of 50 μm.

(3) Production of metal clad laminates (copper clad laminates)

After stacking 4 sheets of the prepreg prepared in (1), an electrolytic copper foil "YGP-18" (manufactured by Nippon Electron Co., Ltd., trade name) with a thickness of 18 μm was applied so that the adhesive surface was in close contact with the prepreg. overlapped with the overlapped On both sides of the prepreg, a double-sided copper-clad laminate was fabricated under the conditions of 200°C for 60 minutes and a vacuum pressure of 4MPa. In addition, the copper foil with the resin was superimposed so that the resin surfaces face each other, and a double-sided copper-clad laminate was produced under the condition of 200° C. for 60 minutes and a vacuum pressure of 4 MPa.

[Evaluation methods for varnishes, prepregs and metal-clad laminates] (1) Varnish property

The varnish property was evaluated by placing the prepared varnish in a transparent container and observing the appearance after 24 hours with the naked eye to observe the separation and deposition of the varnish components. If the hue of the varnish is uniform, it is judged that it is not separated. In addition, it was judged that there was no deposit when it was not confirmed with the naked eye that the deposit was deposited on the bottom of the container. The results are shown in Tables 1 and 2.

(2) Viscosity of prepreg

The evaluation of the viscosity of the prepreg is to process the obtained prepreg into a size of 250mm × 250mm and overlap 100 pieces, put it into a bag that can be sealed in an airtight manner, and then put it into a bag with a temperature of 25°C and a humidity of 70%. In a constant temperature and humidity environment, observe whether the prepregs are in close contact with each other. After 48 hours, the prepreg arranged at the bottom and the prepreg adjacent to it were peeled off, and when each prepreg maintained the surface before injection, it was determined that no adhesion occurred, and it was judged that there was no adhesion. question. The results are shown in Tables 1 and 2.

(3) Appearance of prepreg (presence or absence of aggregates)

The appearance of the prepreg was assessed using a 20x magnifying glass to observe the formation of agglutinates. The results are shown in Tables 1 and 2.

(4) Stored elastic modulus

The storage elastic modulus was evaluated by etching the entire surface of the copper-clad laminate obtained by overlapping the copper foil with the resin so that the resin surfaces face each other to obtain a laminate, and cutting the laminate into After a width of 5 mm and a length of 30 mm, the storage elastic modulus was calculated using a dynamic viscoelasticity measuring device (manufactured by UBM Co., Ltd.). When the storage elastic modulus at 25° C. was 2.0×10 ⁹ Pa or less, it was judged that the stress relaxation effect could be exhibited. The results are shown in Tables 1 and 2.

(5) Tensile elongation

The tensile elongation is evaluated by etching the entire surface of a copper-clad laminate obtained by overlapping the resin-attached copper foil so that the resin surfaces face each other to obtain a laminate, and cutting the laminate into After a width of 10 mm and a length of 100 mm, the tensile elongation was calculated using an autograph (manufactured by Shimadzu Corporation). When the tensile elongation at 25° C. is 3% or more, it is judged that the stress relaxation effect can be exhibited. The results are shown in Tables 1 and 2.

(6) Heat resistance

A test piece was obtained by cutting the double-sided copper-clad laminate obtained from the prepregs that were superimposed on 4 sheets into a square with four sides of 50 mm. This test piece was immersed in the solder bath of 260 degreeC, and the time which elapsed from the time point until the time point when the swelling of the test piece could be confirmed with the naked eye was measured. The measurement of the elapsed time was set to 300 seconds, and it was judged that the heat resistance was sufficient for 300 seconds or more. The results are shown in Tables 1 and 2.

(7) Evaluation of the adhesion of metal foil to substrate

A part of the copper foil of the double-sided copper-clad laminate obtained by stacking four prepregs was etched to form a copper foil line with a width of 3 mm. Then, the direction of the copper foil wire was measured to be 90 with respect to the adhesive surface at a speed of 50 mm/min. After the load at the time of direction peeling, it was set as copper foil peeling strength. When the copper foil peeling strength was 0.5 kN/m or more, it was judged that the adhesiveness with the metal foil was sufficient. The results are shown in Tables 1 and 2.

(8) Phase structure observation test

The average area size of the island phase is obtained by smoothing the cross-section of the resin insulating layer of the copper clad laminate obtained by overlapping the copper foil with resin so that the resin surfaces face each other by using a slicing machine. After etching with a sulfate solution, the maximum width and the minimum width of each of 70 or more island phases were measured from the obtained cross-sectional structure using an electron microscope, and the average value was calculated. The results are shown in Tables 1 and 2.

(9) Electrical insulation reliability

The electrical insulation reliability was measured using a test pattern obtained by processing a double-sided copper-clad laminate obtained by stacking 4 sheets of prepregs so that the hole wall spacing of the through-holes was 350 μm. The insulation resistance of 400 holes was measured over time. The measurement conditions were performed by applying 100 V in an environment of 85° C./85% RH, and the time until conduction breakdown occurred was measured. The measurement time was set to 2000 hours, and it was judged that the electrical insulation reliability was sufficient for 1000 hours or more. The results are shown in Tables 1 and 2.

*1: Trade name "KH-CT-865", manufactured by Hitachi Chemical Co., Ltd. (weight average molecular weight: Mw=45×10 ⁴ to 65×10 ⁴ , as a compound represented by formula (1), containing in ester Part of methacrylates with cycloalkyl groups of 5 to 10 carbon atoms and acrylic polymers without nitrile groups in the structure)

*2: Trade name "HTR-860P-3", manufactured by Nagase ChemteX Co., Ltd. (weight average molecular weight: Mw=80×10 ⁴ , acrylic polymer that does not contain a nitrile group in its structure)

*3: Trade name "HAN5-M90S", manufactured by Negami Kogyo Co., Ltd. (weight average molecular weight: Mw=90×10 ⁴ , acrylic polymer that does not contain a nitrile group in its structure)

*4: Trade name "N770", manufactured by DIC Co., Ltd. (phenol novolac epoxy resin)

*5: Trade name "EPICLON 153", manufactured by DIC Co., Ltd. (tetrabromobisphenol A type epoxy resin)

*6: Trade name "NC-3000H", manufactured by Nippon Kayaku Co., Ltd. (biphenyl aralkyl type epoxy resin)

*7: Trade name "4005P", manufactured by Mitsubishi Chemical Corporation, (bisphenol F type epoxy resin)

*8: Trade name "KA-1165", manufactured by DIC Co., Ltd. (cresol novolak resin)

*9: Trade name "SC-2050KC", manufactured by Admatechs Co., Ltd. (fused spherical silica, silane coupling treatment, average particle size 0.5μm)

*10: Trade name "HK-001", manufactured by Kawai Lime Co., Ltd. (aluminum hydroxide, average particle size 4.0 μm)

*11: Trade name "F05-12", manufactured by Fukushima Kiln Co., Ltd. (pulverized silica, average particle size 2.5μm)

*12: Trade name "F05-30", manufactured by Fukushima Kiln Co., Ltd. (pulverized silica, average particle size 4.2μm)

*13: Trade name "2PZ", manufactured by Shikoku Chemical Industry Co., Ltd., (2-phenylimidazole)

*14: Trade name "A-187", manufactured by Dow Corning Toray Co., Ltd. (Silane Coupler)

As is apparent from Table 1, the examples of the present invention are all excellent in low elasticity, heat resistance, adhesion to metal foil, and insulation reliability. On the other hand, all of the comparative examples were not excellent in low elasticity, heat resistance, adhesion to metal foil, and insulation reliability.

The resin composition, prepreg, prepreg with metal foil, laminate, metal-clad laminate and printed circuit board of the present invention have low elasticity, high insulation reliability, high heat resistance, and compatibility with metal High adhesion between foils.

Claims (15)

A prepreg, which is impregnated with a resin composition, a first phase of the resin composition and a second phase serving as an island phase form a phase-separated structure, and the average domain size of the island phase is 3.0 μm to 10 μm, and the resin The composition contains (C) a filler, wherein the first phase contains (A) an acrylic polymer, and the second phase contains (B) a thermosetting resin. When the (A) acrylic polymer is combined with the (B) ) When the total amount of the thermosetting resin is 100 parts by mass, the blending amount of the (A) acrylic polymer is 10 to 70 parts by mass, and the weight average molecular weight of the (A) acrylic polymer is 300,000 to 1,500,000. The prepreg according to claim 1, wherein the resin composition contains (C-1) a coupling-treated filler as the aforementioned (C) filler. The prepreg according to claim 1, wherein the resin composition contains (C-2) an uncoupling filler as the (C) filler. The prepreg according to claim 1, wherein the (B) thermosetting resin includes (B-1) epoxy resin and (B-2) phenol resin. The prepreg according to claim 4, wherein the epoxy resin (B-1) contains an epoxy resin having two or more epoxy groups in one molecule. The prepreg according to claim 4, wherein the aforementioned (B-1) The weight average molecular weight of the epoxy resin is 200 to 1,000. The prepreg according to claim 4, wherein the epoxy equivalent of the epoxy resin (B-1) is 150 to 500. The prepreg according to claim 1, wherein the weight average molecular weight of the (A) acrylic polymer is 450,000 to 1,500,000. The prepreg according to claim 4, wherein the (B-2) phenol resin contains a phenol resin having two or more hydroxyl groups in one molecule. The prepreg according to claim 1, wherein silicon oxide is contained as the (C) filler. The prepreg according to claim 1, wherein the volume average particle size of the filler (C-2) is 1.0 μm to 3.5 μm. A prepreg with metal foil, which is obtained by laminating the prepreg and metal foil according to any one of claims 1 to 11. A laminate having the prepreg according to any one of claims 1 to 11. A metal-clad laminate comprising the laminate described in claim 13 further including metal foil. A printed circuit board obtained by further adding a circuit to the laminate described in claim 13.

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