JPH10183076A - Adhesive film for printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an adhesive film which has a good adhesiveness and is excellent in handleability without causing dusting or cracks by compounding a high-mol.-wt. epoxy resin, a solvent-soluble polyamide resin, and a polyfunctional epoxy resin. SOLUTION: A high-mol.-wt. epoxy resin in an amount of 100 pts.wt. having a wt. average mol.wt. of 50,000 or higher and obtd. by copolymerizing a difunctional epoxy resin (e.g. a bisphenol type A epoxy resin or a bisphenol F type epoxy resin) with a difunctional phenol (e.g. hydroquinone or resorcinol), 1-100 pts.wt. polyamide soluble in an amide solvent, a ketone solvent, or a lactone solvent, and pref. having an arom. residue in the molecular chain, and 5-200 pts.wt. polyfunctional epoxy resin having at least two epoxy groups in the molecule are compounded to give an adhesive film for printed circuit boards.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive film for a printed wiring board.

[0002]

2. Description of the Related Art As an interlayer insulating material capable of increasing the density and thickness of a multilayer printed wiring board, there is an adhesive film that can be handled without using a continuous substrate such as glass cloth. As the organic material used for the adhesive film, polyimide resin or epoxy resin is used.
It is useful to use an epoxy resin as a main component from the viewpoint of cost and the like, and JP-A-4-119846 discloses an epoxy resin film composed of a high-molecular-weight epoxy resin. JP-A-4-339852 discloses an epoxy resin composition comprising a high-molecular-weight epoxy resin, a polyfunctional epoxy resin and a curing agent and capable of producing an epoxy adhesive film.

[0003]

By mixing a polyfunctional epoxy resin with a high molecular weight epoxy resin, it is possible to obtain an adhesive film for printed wiring boards having good adhesiveness. However, the addition of a polyfunctional epoxy resin with a relatively low molecular weight makes the semi-cured adhesive film brittle, easily falling off when cut, and easily cracking. There was a problem of inferiority. An object of the present invention is to provide an adhesive film for a printed wiring board which is excellent in handleability without causing powder dropping or cracking and has good adhesiveness.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and have reached the present invention. The present invention is an adhesive film for a printed wiring board, comprising (1) a high molecular weight epoxy resin, (2) a solvent-soluble polyamide resin, and (3) a polyfunctional epoxy resin. The present invention is also an adhesive film for a printed wiring board, wherein the high molecular weight epoxy resin is a high molecular weight epoxy resin having a weight average molecular weight of 50,000 or more obtained by polymerizing a bifunctional epoxy resin and a bifunctional phenol resin. Further, the present invention provides
Solvent-soluble polyamide resin solvent, amide solvent,
The adhesive film for a printed wiring board, which is at least one of a ketone solvent and a lactone solvent, wherein the polyamide resin is an adhesive film for a printed wiring board having an aromatic residue.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be described below in detail. The adhesive film for printed wiring boards of the present invention is a high-molecular weight epoxy resin, a solvent-soluble polyamide resin, an adhesive varnish in which a composition containing a polyfunctional epoxy resin is dissolved, and dried to form a semi-cured film. can get. The high molecular weight epoxy resin used in the present invention can be obtained by heating and polymerizing a bifunctional epoxy resin and a bifunctional phenol resin in an amide or ketone solvent in the presence of a catalyst. The high molecular weight epoxy resin preferably has a molecular weight of 50,000 or more, and a weight average molecular weight of 100,
It is more preferable if it is 000 or more. In order to make the adhesive flame-retardant, the high-molecular-weight epoxy resin is preferably halogenated, and particularly preferably brominated.

[0006] The bifunctional epoxy resin is not limited as long as it is a compound having two epoxy groups in the molecule. For example, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, alicyclic epoxy resin Epoxy resins, aliphatic chain epoxy resins, diglycidyl ether compounds of bifunctional phenols, diglycidyl ether compounds of bifunctional alcohols, halides thereof, hydrogenated products thereof, and the like can be used.
The molecular weight of these compounds is not limited, and several kinds can be used in combination.

[0007] The bifunctional phenol resin is not limited as long as it is a compound having two phenolic hydroxyl groups.
Monocyclic bifunctional phenols such as hydroquinone, resorcinol, and catechol, and polycyclic bifunctional phenols such as bisphenol A and bisphenol F, and halides and substituted alkyl groups thereof can be used. The molecular weight of these compounds is not limited, and several kinds can be used in combination.

[0008] The catalyst in the present invention is a compound having a catalytic activity to promote an etherification reaction between an epoxy group and a phenolic hydroxyl group, and includes an alkali metal hydroxide, an alkali metal alcoholate, an alkali metal phenolate, and an alkyl phosphorus-based catalyst. And at least one selected from aliphatic cyclic amine catalysts. The alkali metal of the alkali metal hydroxide, alkali metal alcoholate and alkali metal phenolate is sodium, lithium and potassium, and these catalysts can be used in combination with other catalysts.
Alkyl phosphorus catalysts include tri-n-propylphosphine, tri-n-butylphosphine and the like. As an aliphatic cyclic amine catalyst, 1,4-diazabicyclo [2,
2,2] octane, 1,5-diazabicyclo [4,3,0]-
5-nonane, 1,8-diazabicyclo [5,4,0] -7-
And undecene. The amount of the catalyst is not particularly limited.
It is about 001 to 0.2 mol. When the amount is less than this range, the reaction for increasing the molecular weight is remarkably slow, and when the amount is more than this range, the side reaction increases and the molecular weight may not be increased linearly.

The ketone solvent having a boiling point of 100 ° C. or higher in the present invention may be any solvent as long as it dissolves the epoxy resin and phenols as raw materials. For example, methyl isobutyl ketone, 2-heptanone, 4-heptanone,
Aliphatic ketone solvents such as -octanone, cyclohexanone, and acetylacetone; cycloaliphatic ketone solvents; and aliphatic diketone solvents. These solvents can be used in combination. Further, it may be used in combination with other solvents such as amide solvents and ether solvents.

Examples of the amide solvents include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide,
N-dimethylacetamide, N, N, N ', N'-tetramethylurea, 2-pyrrolidone, N-methylpyrrolidone and the like.

As for the production conditions, the blending equivalent ratio of the bifunctional epoxy resin and the bifunctional phenol is set so that epoxy group / phenolic hydroxyl group = 1: 0.9 to 1.1. When the amount is less than 0.9 equivalent, a side reaction occurs without causing a high molecular weight in a linear form, resulting in crosslinking and insolubility in a solvent. If it is more than 1.1 equivalents, the increase in the molecular weight will not proceed. The polymerization reaction temperature is 60 to 15
Desirably, the temperature is 0 ° C. If the temperature is lower than 60 ° C., the reaction for increasing the molecular weight is remarkably slow, and if it is higher than 150 ° C., side reactions increase and the molecular weight may not be increased linearly. Preferably, the temperature is 130 ° C. or less. The resulting high molecular weight epoxy resin has a reduced viscosity of 0.6 dl / g (30 ° C., N,
(N-dimethylacetamide) or more. The solid content concentration during the polymerization reaction is set to 50% by weight or less, more preferably 30% by weight or less. As the concentration increases, side reactions increase and it becomes difficult to increase the molecular weight in a linear manner. Therefore, when performing a polymerization reaction at a relatively high concentration and obtaining a linear high molecular weight epoxy resin, the reaction temperature may be lowered and the amount of catalyst may be reduced.

The high-molecular-weight epoxy resin obtained by the present invention is a high-molecular-weight epoxy resin having a film-forming ability, and has less branches and higher molecular weight than conventional high-molecular-weight epoxy resins. Is considered
It has sufficient film forming ability. The resulting film has characteristics that cannot be realized by a film molded using a conventional high molecular weight epoxy resin. That is,
The strength is remarkably large and the elongation is remarkably large.

The solvent-soluble polyamide resin used in the present invention is not limited as long as it has an acid amide bond in the molecular chain and is soluble in an organic solvent or water. For example, polyamide 6/66, 6 / 66/12, etc .; aliphatic dicarboxylic acids such as adipic acid and succinic acid, glutaric acid, azelaic acid, sebacic acid, dimer acid and the like, and aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid and phthalic acid; Hexamethylenediamine, aromatic diamines such as diaminodiphenylmethane, diaminodicyclohexylmethane, aliphatic diamines such as isophoronediamine, or aromatic isocyanates, amorphous synthesized using components that inhibit crystallinity such as aliphatic isocyanates Poly containing flexible components such as nylon and polyglycols Bromide elastomer, formalin-modified polyamide and the like. Further, the solvent for dissolving the polyamide, since the high molecular weight epoxy resin has good solubility in amide solvents or ketone solvents,
Those which are soluble in amide-based or ketone-based solvents or lactone-based solvents or which have an aromatic residue in the molecular chain are preferred. Examples of such a solvent-soluble polyamide resin include Trogamide T-5000 (trade name, manufactured by Daicel Huls), CM4000 (trade name, manufactured by Toray Industries, Inc.) and the like. In order to improve the handleability of the semi-cured adhesive film and the heat resistance of the cured adhesive film, the amount of the solvent-soluble polyamide resin is from 1 part by weight to 100 parts by weight based on 100 parts by weight of the high molecular weight epoxy resin. It is preferably in the range of parts.

The polyfunctional epoxy resin used in the present invention is not limited as long as it is a compound having two or more epoxy groups in a molecule. For example, phenol novolak epoxy resin, cresol novolak epoxy resin, salicylaldehyde novolak Epoxy resins, glycidyl ethers of phenols such as bisphenol epoxy resins, alicyclic epoxy resins, aliphatic chain epoxy resins, glycidyl ester epoxy resins, glycidylamine epoxy resins, hydantoin epoxy resins, There are isocyanurate type epoxy resins, epoxidized polybutadienes, flexible epoxy resins and the like, and halides and hydrogenated products thereof. These compounds can be used alone or in combination of several kinds. In order to improve the heat resistance of the adhesive film, the amount of the polyfunctional epoxy resin is preferably 5 to 200 parts by weight based on 100 parts by weight of the high molecular weight epoxy resin. If it is less than 5 parts by weight, the adhesiveness is poor, and if it exceeds 200 parts by weight, the handleability of the film is inferior.

Further, in the present invention, a curing agent for epoxy resin and a curing accelerator can be used. The curing agent for the epoxy resin, the curing accelerator is not limited as long as it cures the epoxy resin, and includes novolak-type phenol resins, dicyandiamide, acid anhydrides, amines, imidazoles, phosphines, and these compounds. Can be used alone or in combination.

If necessary, a crosslinking agent for a high molecular weight epoxy resin, a silane coupling agent and a flame retardant may be added. As a crosslinking agent for high molecular weight epoxy resin, 2
There are polyisocyanates having two or more isocyanate groups, and blocked polyisocyanates in which isocyanate groups are blocked by using a masking agent. Examples thereof include tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and the above polyisocyanates. Block-type polyisocyanate obtained by blocking with a phenol, an oxime, an alcohol, or an amine. These isocyanates can be used alone or in combination of several kinds. Among them, isophorone diisocyanate or tolylene diisocyanate blocked with a novolak type phenol resin is heat-resistant when used as an adhesive for printed wiring boards. It is preferable because of good properties. The silane coupling agent is preferably epoxy silane, amino silane, urea silane, or the like. The flame retardant has reactivity with the constituents of the adhesive described in the present invention, such as a halogenated epoxy resin, preferably a brominated epoxy resin or a polyfunctional halogenated phenol, preferably a polyfunctional brominated phenol. Reaction-type flame retardants and additive-type flame retardants such as nitrogen-based flame retardants, phosphorus-based flame retardants, and inorganic flame retardants can be used.

In order to dissolve or mix the above components to form an adhesive varnish, an organic solvent in which the components of the adhesive are soluble can be used. As such an organic solvent, an amide solvent, a ketone solvent or a lactone solvent can be used. Examples of amide solvents include
N-methylpyrrolidone, formamide, N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, and the like. Examples of ketone solvents include acetone, methylethylketone, methylisobutylketone, and heptanone. , Cyclohexanone, octanone, holon, isophorone, acetophenone and the like, and lactone solvents such as γ-butyrolactone. These solvents may be used alone or in combination of several kinds. In addition, as these solvents, the synthesis solvent for the adhesive component can be used as it is.

The adhesive film for a printed wiring board of the present invention is prepared by applying the adhesive varnish to a plate-shaped or roll-shaped substrate and drying it. There is no particular limitation on the substrate on which the adhesive film varnish is applied, but a carrier film such as a polyethylene terephthalate film, or an adhesive film varnish applied to a copper foil and dried to form an adhesive film with a carrier film or a copper foil. Can be obtained. Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

[0019]

【Example】

(Example 1) (Synthesis of high molecular weight epoxy resin) A bisphenol A type epoxy resin (epoxy equivalent: 172) was used as a bifunctional epoxy resin, and tetrabromobisphenol A (hydroxyl equivalent:
272), and an epoxy group / phenol hydroxyl group = 1 /
1.02, lithium hydroxide as a catalyst in the presence of 0.065 mol per mol of epoxy resin, N, N-dimethylacetamide as a reaction solvent, and a solid concentration of the solution of 30. % By weight and heated at 120 ° C. for 10 hours for polymerization. The obtained high molecular weight epoxy resin has a weight average molecular weight in terms of styrene of 15 by gel permeation chromatography (GPC).
The reduced viscosity was 1.22 dl / g in N, N-dimethylacetamide at 30 ° C.

100 parts by weight of a brominated high molecular weight epoxy resin having a weight average molecular weight of 155,000 synthesized above as a high molecular weight epoxy resin and T-5000 as a solvent-soluble polyamide resin (trade name, manufactured by Daicel Huls Co., Ltd.) 20 parts by weight, bisphenol A type epoxy resin (epoxy equivalent: 172) 30 as a polyfunctional epoxy resin
10 parts by weight of isophorone diisocyanate blocked by phenol novolak was dissolved in an organic solvent containing dimethylacetamide to obtain an adhesive film varnish having a solid content of 40% by weight. An adhesive film varnish is applied to a 50 μm-thick polyethylene terephthalate film as a carrier film so that the thickness of the dried adhesive film is 50 μm, and is applied at 100 ° C. for 2 minutes.
After drying at 0 ° C. for 2 minutes, an adhesive film with a carrier film was obtained. This adhesive film with a carrier film showed no powder dropping at the time of cutting, and showed good handling without cracking when removing the carrier film. Also, sandwich the adhesive film between 18μm copper foil,
It was shaped by heating and pressing at 170 ° C. and 4 MPa for 60 minutes, and the copper foil peeling strength was measured to be 1.5 kN /
m.

(Example 2) A bisphenol A type epoxy resin used in Example 1 was replaced with a phenol novolak type epoxy resin (epoxy equivalent: 175).
An adhesive film varnish was obtained in the same manner as in Example 1, and an adhesive film with a carrier film was obtained. This adhesive film with a carrier film showed no powder dropping at the time of cutting, and showed good handling without cracking when removing the carrier film. Also, an adhesive film is sandwiched between 18 μm copper foils, and is heated at 170 ° C., 4 MPa, 60
It was 1.5 kN / m when the copper foil was peeled off by heating and pressurizing for 5 minutes.

Example 3 An adhesive film varnish was obtained in the same manner as in Example 2 except that the phenol novolak-blocked isophorone diisocyanate used in Example 1 was not used, and an adhesive film with a carrier film was obtained. This adhesive film with a carrier film showed no powder dropping at the time of cutting, and showed good handling without cracking when removing the carrier film. In addition, an adhesive film is sandwiched between 18 μm copper foils,
The molded product was heated and pressurized at 4 ° C. for 60 minutes, and the copper foil peeling strength was measured to be 1.4 kN / m.

Comparative Example 1 An adhesive film varnish was obtained in the same manner as in Example 1 except that the solvent-soluble polyamide resin used in Example 1 was not added, and an adhesive film with a carrier film was obtained. This adhesive film with a carrier film was powdery when cut, and cracked when the carrier film was removed, making handling difficult. Further, the adhesive film was sandwiched between 18 μm copper foils, heated and pressed at 170 ° C., 4 MPa for 60 minutes, and the copper foil peeling strength was measured.
It was 6 kN / m. Table 1 summarizes the properties of the adhesive films shown in Examples 1, 2, and 3 and Comparative Example 1.

[0024]

[Table 1]

[0025]

According to the present invention, an adhesive film containing (1) a high-molecular-weight epoxy resin, (2) a solvent-soluble polyamide resin, and (3) a polyfunctional epoxy resin has excellent handleability, heat resistance, An adhesive film for printed wiring boards having good adhesiveness can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // B32B 27/38 B32B 27/38 (72) Inventor Kazunori Yamamoto 1500 Ogawa Oji, Shimodate City, Ibaraki Prefecture Hitachi Chemical Industry Co., Ltd. Shimodate Research Inside

Claims (4)

[Claims] 1. An adhesive film for a printed wiring board comprising (1) a high molecular weight epoxy resin, (2) a solvent-soluble polyamide resin, and (3) a polyfunctional epoxy resin. 2. The adhesive for printed wiring boards according to claim 1, wherein the high molecular weight epoxy resin is a high molecular weight epoxy resin having a weight average molecular weight of 50,000 or more obtained by polymerizing a bifunctional epoxy resin and a bifunctional phenol resin. the film. 3. The solvent of a solvent-soluble polyamide resin,
The adhesive film for a printed wiring board according to claim 1, wherein the adhesive film is an amide-based solvent, a ketone-based solvent, or a lactone-based solvent. 4. The adhesive film for a printed wiring board according to claim 1, wherein the polyamide resin has an aromatic residue.