JPH10237271A - Thermosetting resin composition, film or sheet adhesive and adhesive-coated metal foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition improved in relative permittivity, dielectric loss tangent and water absorptivity by using a linear high-molecular-weight epoxy polymer, a polyfunctional epoxy resin and a polyphenylene sulfide as the essential components and to obtain a film adhesive formed therefrom and an adhesive-coated metal foil. SOLUTION: The linear high-molecular weight epoxy polymer is obtained by reacting a difunctional epoxy resin with a difunctional phenol resin in the presence of an etherification catalyst in a solvent under heating. The catalyst is used in an amount of 0.0001-0.2mol per mol of the difunctional epoxy resin. The solvent is suitably an amide solvent having a boiling point of 130 deg.C or above (e.g. formamide or acetamide). The polyfunctional epoxy resin comprises at least one epoxy compound having at least two epoxy groups on the average per molecule. The polyhenylene sulfide is a commercially available one. It is desirable that the linear high-molecular-weight epoxy polymer is used in an amount of 40-70 pts.wt. per 100 pts.wt. total of the three essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition, a film-like or sheet-like adhesive and a metal foil with an adhesive, and more particularly to a thermosetting resin composition suitable for electrical insulation bonding. The present invention relates to a film-like or sheet-like adhesive made of the thermosetting resin composition as a material (hereinafter, the film-like or sheet-like is simply referred to as a film-like) adhesive and a metal foil with an adhesive using this thermosetting resin as an adhesive.

[0002]

2. Description of the Related Art Thermosetting resin compositions in which a polyfunctional epoxy resin and a curing agent are blended with a linear high molecular weight epoxy polymer are excellent as insulating adhesives for electronic materials (JP-A-5-25368). Reference). A film-like adhesive obtained by forming the thermosetting resin composition into a film has excellent adhesiveness and heat resistance, and is used as an insulating adhesive material between an outer layer material and an inner layer material of a multilayer printed wiring board. A metal foil with an adhesive provided with an adhesive layer made of the thermosetting resin composition on one side of the metal foil is used as an outer layer base material of a multilayer printed wiring board.

[0003]

The use of a printed wiring board in an electronic device is indispensable. However, as the speed of signal propagation in an electronic device becomes higher and the frequency becomes higher, the propagation delay of a signal in a printed wiring circuit and the transmission loss are increased. And crosstalk is becoming an issue. Signal propagation delay is proportional to the square root of the dielectric constant of the insulating layer material that the printed wiring circuit is in contact with, and crosstalk is also likely to occur in proportion to the capacitance of the insulator that the printed wiring circuit is in contact with. Become. This capacitance is proportional to the relative dielectric constant of the insulating layer material. Also,
The transmission loss increases as the dielectric loss tangent increases. Therefore, the insulating layer material of the printed wiring board is required to have low relative dielectric constant and low dielectric loss tangent.

[0004] Further, since the relative dielectric constant varies depending on the moisture absorption state of the insulating layer material, it is required that the insulating layer material with which the high-frequency printed circuit is in contact has a low water absorption.

However, a thermosetting resin composition in which a polyfunctional epoxy resin and a curing agent are blended with a linear high molecular weight epoxy polymer has a relative dielectric constant, dielectric loss tangent and water absorption that are not always satisfactory for high frequency applications. I couldn't do it. An object of the present invention is to improve the relative dielectric constant, dielectric loss tangent, and water absorption of a thermosetting resin composition in which a polyfunctional epoxy resin is mixed with a linear high molecular weight epoxy polymer.

Further, the present invention relates to a film adhesive obtained by forming a thermosetting resin composition obtained by blending a polyfunctional epoxy resin with a linear high molecular weight epoxy polymer into a film. And to improve the water absorption.

Further, the present invention relates to a metal foil with an adhesive in which an adhesive layer made of a thermosetting resin composition in which a polyfunctional epoxy resin is blended with a linear high molecular weight epoxy polymer is formed on one surface. It is an object to improve relative dielectric constant, dielectric loss tangent, and water absorption.

[0008]

According to the first aspect of the present invention, a linear high molecular weight epoxy polymer, a polyfunctional epoxy resin and a polyphenylene sulfide obtained by reacting a bifunctional epoxy resin with a bifunctional phenol are essential. It is a thermosetting resin composition contained as a component.

Further, the invention of claim 2 contains, as essential components, a linear high molecular weight epoxy polymer obtained by reacting a bifunctional epoxy resin with a bifunctional phenol, a polyfunctional epoxy resin, and polyphenylene sulfide. It is a film adhesive obtained by forming a thermosetting resin composition into a film.

A third aspect of the present invention is a linear high molecular weight epoxy polymer, a polyfunctional epoxy resin and a polyphenylene obtained by reacting a bifunctional epoxy resin with a bifunctional phenol on one surface of a metal foil. Metal foil with an adhesive provided with an adhesive layer made of a thermosetting resin composition containing sulfide as an essential component.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The linear high molecular weight epoxy polymer used in the present invention is obtained by reacting a bifunctional epoxy resin with a bifunctional phenol by heating in a solvent in the presence of an etherification catalyst. Obtainable.

The bifunctional epoxy resin may be any compound as long as it has two epoxy groups in the molecule, such as a bisphenol A epoxy resin, a bisphenol F epoxy resin, and a bisphenol S epoxy resin. , Alicyclic epoxy resin, aliphatic chain epoxy resin, diglycidyl etherified bifunctional phenol, diglycidyl etherified bifunctional alcohol,
These halides include these hydrogenated products.
There is no limitation on the molecular weight of these compounds. Some of these compounds can be used in combination.

The bifunctional phenol may be any compound as long as it has two phenolic hydroxyl groups in the molecule. Examples thereof include monocyclic bifunctional phenols such as hydroquinone, resorcinol, catechol, and polycyclic bifunctional phenol. There are bisphenol A and bisphenol F which are functional phenols, halides and alkyl-substituted products thereof.
There is no limitation on the molecular weight of these compounds. As with the bifunctional epoxy resin, these compounds can be used in combination of several kinds.

The etherification catalyst is a catalyst which promotes the etherification reaction between the epoxy group and the phenolic hydroxyl group, and a compound having a catalytic function which promotes the etherification reaction between the epoxy group and the phenolic hydroxyl group is used. Is done. Examples include alkali metal compounds, alkaline earth metal compounds, imidazoles, organic phosphorus compounds, secondary amines, tertiary amines, quaternary ammonium salts, and the like. Examples of alkali metal compounds include sodium,
Hydroxide, halide, organic acid salt, alcoholate, phenolate, hydride, borohydride or amide, lithium, hydroxide, halide, organic acid salt, alcoholate, phenolate, hydride, borohydride or amide , Potassium hydroxide, halides, organic acid salts, alcoholates, phenolates, hydrides, borohydrides or amides. These can be used in combination.

The amount of the etherification catalyst is not particularly limited, but is generally about 0.0001 to 0.2 mol per 1 mol of the bifunctional epoxy resin. The amount of the catalyst was 0.0001 to 1 mol of the bifunctional epoxy resin.
If the amount is less than 10 mol, the reaction for increasing the molecular weight is extremely slow,
If the amount is more than 2 mol, side reactions may increase and the molecular weight may not be increased linearly.

Since the reaction between the bifunctional epoxy resin and the bifunctional phenol is performed by heating in a solvent, it is preferable to use an amide-based solvent having a boiling point of 130 ° C. or higher as a solvent. The amide-based solvent may be any as long as it can dissolve the bifunctional epoxy resin and the bifunctional phenol as raw materials. Examples thereof include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide. N, N, N ',
N'tetramethylurea, 2-pyrrolidone, N-methylpyrrolidone, carbamic acid esters, and the like. These solvents can be used in combination.

When a bifunctional epoxy resin is reacted with a bifunctional phenol in a solvent, the solid concentration of the reaction component is 5%.
It is preferable to carry out at a rate of ５０50% (weight%, the same applies hereinafter). When the solid content of the reaction component is less than 5%, the reaction is slow and it is difficult to increase the molecular weight. On the other hand, if it exceeds 50%, side reactions increase, and it is difficult to increase the molecular weight in a linear manner. For this reason, the solid content concentration of the reaction component is more preferably set to 10 to 30%. When the reaction is carried out at a high concentration, it is preferable to lower the reaction temperature and reduce the blending amount of the etherification catalyst.

When the blending equivalent ratio of the bifunctional epoxy resin and the bifunctional phenol is determined as follows: epoxy group / phenol hydroxyl group = 1 /
By reacting as (0.9 to 1.1), a linear high molecular weight epoxy polymer having film forming ability can be obtained. Here, having a film-forming ability, for example, a film can be formed when a raw material dissolved in a solvent is cast on a substrate, and the formed film is conveyed, during a process such as cutting and lamination. , Which means that troubles such as cracks and dropouts are unlikely to occur. Epoxy group 1
If the equivalent of the phenolic hydroxyl group to the equivalent is less than 0.9 equivalent, the resin may not be polymerized linearly, but may be cross-linked by a side reaction to make the resin insoluble. In addition, epoxy group 1
When the equivalent of the phenolic hydroxyl group to the equivalent is more than 1.1 equivalent, the obtained polymer tends to have insufficient film-forming ability.

If the molecular weight of the linear high molecular weight epoxy polymer is about 70,000 or more as a weight average molecular weight (hereinafter simply referred to as molecular weight) determined by gel permeation chromatography in terms of standard polystyrene, the film-forming ability is reduced. Have. In order to have a practically sufficient film-forming ability, the molecular weight of the linear high molecular weight epoxy polymer is preferably set to 100,000 or more. When a bifunctional epoxy resin is reacted with a bifunctional phenol, the molecular weight of the linear high molecular weight epoxy polymer tends to increase as the equivalent ratio of epoxy group / phenol hydroxyl group approaches 1. It can also be adjusted by the amount of the etherification catalyst and the reaction conditions. The upper limit of the molecular weight of the linear high molecular weight epoxy polymer is not particularly limited, but if it is too large, the solubility in a solvent decreases.

As the polyfunctional epoxy resin, an epoxy compound having an average of two or more epoxy groups per molecule,
For example, bisphenol epoxy resin, halogenated bisphenol epoxy resin, bisphenol novolak epoxy resin, halogenated bisphenol novolak epoxy resin, alkylphenol novolak epoxy resin, polyphenol epoxy resin, polyglycol epoxy resin, cycloaliphatic epoxy Resins. These can be used alone or in combination of two or more.

In order to cure the polyfunctional epoxy resin, it is necessary to incorporate a curing agent. Any curing agent may be used as long as it is a curing agent for a polyfunctional epoxy resin.
Representative examples include polyfunctional phenols, amines, imidazoles, and acid anhydrides. The curing agent is
What is necessary is just to mix | blend the amount required for hardening a polyfunctional epoxy resin. The appropriate range is set depending on the polyfunctional epoxy resin and the curing agent to be blended. As polyfunctional phenols,
Monocyclic bifunctional phenols such as hydroquinone, resorcinol, catechol, and polycyclic bifunctional phenols such as bisphenol A and bisphenol F, naphthalene diols and biphenols, as well as halides and alkyl-substituted products of these polyfunctional phenols Can be
Novolak and resol, which are polycondensates of these polyfunctional phenols and aldehydes, can also be used. Examples of the amines include aliphatic primary amines, aliphatic secondary amines, aliphatic tertiary amines, aromatic primary amines, aromatic secondary amines, aromatic tertiary amines, guanidines, and urea derivatives. Specific examples include triethylenetetramine, diaminodiphenylmethane, diaminodiphenylether, dicindiamide, tolylbiguanide, guanylurea, and dimethylurea. Examples of imidazoles include alkyl-substituted imidazole, benzimidazole and the like. Examples of the acid anhydride include phthalic anhydride, hexahydrophthalic anhydride, pyromellitic dianhydride, and benzophenonetetracarboxylic dianhydride.

As polyphenylene sulfide, commercially available products can be used. Commercial products of polyphenylene sulfide include FORTRON 1140A1, 114
0A4, (Polyplastics Corporation, trade name), Toprene T-4 (Toprene Corporation, trade name) and the like.

When the total amount of the linear high molecular weight epoxy polymer, the polyfunctional epoxy resin and the polyphenylene sulfide is 100 parts by weight, the amount of the linear high molecular weight epoxy polymer is preferably 40 to 70 parts by weight. If the amount of the linear high molecular weight epoxy polymer is less than 40 parts by weight, it tends to be brittle and the handleability tends to be poor. On the other hand, if it exceeds 70 parts by weight, the fluidity at the time of heat curing is low, and when used in the production of a multilayer printed wiring board, the embedding of irregularities in the surface circuit of the inner layer material becomes insufficient. The polyfunctional epoxy resin and the polyphenylene sulfide are, when the total amount of the linear high molecular weight epoxy polymer, the polyfunctional epoxy resin and the polyphenylene sulfide is 100 parts by weight, the polyfunctional epoxy resin is 15 to 55 parts by weight, and the polyphenylene sulfide is The sulfide is also preferably blended in the range of 15 to 55 parts by weight. When the polyfunctional epoxy resin is less than 15 parts by weight, the adhesiveness is poor, and when the polyphenylene sulfide is less than 15 parts by weight, the effect of improving the relative dielectric constant, the dielectric loss tangent and the water absorption is reduced. If the blending amount of any of the polyfunctional epoxy resin and the polyphenylene sulfide exceeds 55 parts by weight, the blending amount of one or both of the other two components becomes relatively small, which is not preferable. From this,
When the total amount of the linear high molecular weight epoxy polymer, the polyfunctional epoxy resin and the polyphenylene sulfide is 100 parts by weight, 40 to 60 parts by weight of the linear high molecular weight epoxy polymer, 15 to 25 parts by weight of the polyfunctional epoxy resin, It is more preferable to blend the polyphenylene sulfide in the range of 25 to 35 parts by weight.

The thermosetting resin composition of the present invention is used as a varnish. As a solvent for the varnish, the synthesis of a linear high molecular weight epoxy polymer is carried out in a solvent. It is preferable to use the solvent used for the above as it is. That is, a varnish is obtained by dissolving components such as a polyfunctional epoxy resin, polyphenylene sulfide, and a curing agent in a linear high molecular weight epoxy polymer solution obtained by reacting a bifunctional epoxy resin with a bifunctional phenol. preferable.

The obtained varnish is applied and dried as it is on the adherend surface of the adherend, and the adherend is adhered by applying heat and pressure with the applied surfaces facing each other. At this time, the temperature is 100 to 250 ° C,
It is preferable to heat and press at a pressure of 0.1 to 10 MPa for 20 minutes or more. If both the temperature and the pressure are outside these ranges, the peel strength tends to gradually decrease. For this reason, it is particularly preferable to heat and press at a temperature of 150 to 200 ° C. and a pressure of 1 to 4 MPa for 60 to 120 minutes.

When a varnish is formed into a film adhesive by a method such as casting, the adhesive can be heated and pressurized while being sandwiched between adherends, thereby facilitating the bonding operation. The thickness is not particularly limited, but is 0.01 to
It is selected in the range of 0.1 mm depending on the application and the adherend to be bonded. Also, other thermosetting resins, for example,
As in the case of the epoxy resin or the like, the varnish may be impregnated into a fiber base and dried to be used as a prepreg. As the fiber base material, a fiber base material for prepreg such as glass cloth, glass mat, aromatic polyamide fiber cloth, aromatic polyamide fiber mat and the like can be generally used. The conditions for bonding the adherend using the film adhesive or the prepreg are the same as those when using the varnish.

Further, the metal foil with an adhesive applied and dried on one side of a metal foil, for example, a copper foil, of a varnish can be used as it is as an outer layer base material when producing a multilayer printed wiring board. . In this way, when forming the interstitial via hole, the outer layer base material can be preliminarily drilled and then bonded to the inner layer material.

[0028]

【Example】

Example 1 (Synthesis of high molecular weight epoxy polymer) 177.5 g of bisphenol A type epoxy resin (epoxy equivalent: 177.5) as a bifunctional epoxy resin and bisphenol A (hydroxyl equivalent: 115.5) 11 as a bifunctional phenol
5.5 g, sodium hydroxide 1.
77 g was dissolved in 683.7 g of N, N-dimethylformamide, which is an amide solvent, to give a solid concentration of 30% in the reaction system. While mechanically stirring this, 125 ° C
The temperature in the reaction system was kept at 120 ° C. in an oil bath of, and the mixture was stirred as it was for 4 hours. As a result, the viscosity is 12,800
The solution was saturated at mPa · s, and a solution (concentration: 30%) of a linear high molecular weight epoxy polymer was obtained. The molecular weight of the obtained linear high molecular weight epoxy polymer was 72,500.
The reduced viscosity of the dilute solution of the high molecular weight epoxy resin was 0.770 dl / g.

(Preparation of Varnish) Bisphenol A was added to 300 g of the linear high molecular weight epoxy polymer solution obtained above.
120 g of a type epoxy resin (epoxy equivalent: 177.5),
A varnish was prepared by dissolving 100 g of polyphenylene sulfide and 1.5 g of Curazole 2E4MZ (Shikoku Chemicals Co., Ltd., trade name) as a curing agent. The polyphenylene sulfide used was Fortron 1140A4 (trade name) manufactured by Polyplastics Co., Ltd.

(Preparation of Film Adhesive) The obtained varnish was cast on a glass plate and dried at 100 ° C. for 10 minutes.
Peel off the glass plate, fix it on an iron frame,
After drying for 5 minutes, a film adhesive having a thickness of 50 μm was prepared.

(Preparation of Four-Layer Printed Wiring Board) Thickness 0.2
mm, copper foil 18 μm thick glass cloth base epoxy resin double-sided copper-clad laminate is etched to form a circuit to form an inner plate, and both sides of this inner plate are thickened via the prepared film adhesive. 35μm copper foil, 180 ℃, 3M
Heating and pressurization was performed at Pa for 90 minutes to produce a four-layer printed wiring board. In addition, the glass cloth base material epoxy resin double-sided copper-clad laminate used MCL-E-67 (trade name) manufactured by Hitachi Chemical Co., Ltd.

Example 2 (Preparation of Copper Foil with Adhesive) The varnish prepared in Example 1 was applied to a roughened surface of a copper foil having a thickness of 35 μm, and heated at 100 ° C. for 10 minutes, and then at 140 ° C. Heat for 15 minutes and thickness 50
A copper foil with an adhesive was produced by providing an adhesive layer of μm. (Production of Four-Layer Printed Wiring Board) The prepared copper foil with adhesive was placed on both sides of the inner layer board in the same manner as in Example 1, and then heated and pressed under the same conditions as in Example 1 to obtain a four-layer printed wiring board. Produced.

Example 3 Tetrabromobisphenol A (hydroxyl equivalent: 271.9) 271.9 instead of 115.5 g of bisphenol A
g and N, N-dimethylformamide 1048.7
g, and a high-molecular-weight linear epoxy polymer was synthesized in the same manner as in Example 1. Thereafter, a four-layer printed wiring board was produced in the same manner as in Example 1.

Comparative Example 1 Instead of 100 g of polyphenylene sulfide, 50 g of a phenol novolak resin (having a hydroxyl equivalent of 106) was added, and a varnish was prepared in the same manner as in Example 1. Thereafter, four-layer printing was performed in the same manner as in Example 1. A wiring board was manufactured.

Comparative Example 2 Using the varnish prepared in Comparative Example 1, a copper foil with an adhesive was produced in the same manner as in Example 2, and a four-layer printed wiring board was produced in the same manner as in Example 2. .

The relative permittivity, dielectric loss tangent, peel strength, water absorption and solder heat resistance of the four-layer printed wiring board produced as described above were examined. Table 1 shows the results. In addition, these test methods are as shown below.

Relative permittivity and dielectric loss tangent: Measured at a frequency of 1 GHz by the bridge method. Peel strength: copper foil on the surface is removed by etching, leaving copper foil 10 mm wide and 100 mm long, and JIS
The examination was carried out in accordance with C6481. Water absorption: Calculated from the change in weight before and after holding for 2 hours in a pressure cooker tester at 121 ° C., 2229 hPa, saturated steam pressure. Solder heat resistance: 50m from the fabricated 4-layer printed wiring board
A test piece having an m-square size was cut out, and the appearance of the test piece after being floated in a solder bath at 260 ° C. for 30 seconds was visually inspected.

[0038]

[Table 1]

[0039]

According to the thermosetting resin composition of the present invention, an insulating layer having a small relative dielectric constant and a small dielectric loss tangent and a small water absorption can be formed. According to the film adhesive and the metal foil with the adhesive according to the third aspect of the present invention, it is possible to form an insulating adhesive layer having a small relative dielectric constant and a low dielectric loss tangent and a small water absorption.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 163/00 C09J 163/00 181/02 181/02 // C08G 65/28 C08G 65/28 (C08L 63/00 81:02 71:08 (72) Inventor Masafumi Tanaka 1500 Ogawa, Oji, Shimodate City, Ibaraki Pref. Hitachi Chemical Industry Co., Ltd.

Claims (3)

[Claims] 1. A thermosetting resin composition comprising, as essential components, a linear high molecular weight epoxy polymer, a polyfunctional epoxy resin and polyphenylene sulfide. 2. A film or sheet adhesive obtained by forming the thermosetting resin composition according to claim 1 into a film or sheet. 3. A metal foil with adhesive provided with an adhesive layer comprising the thermosetting resin composition according to claim 1 on one side of the metal foil.