JPH0931418A - Thermosetting adhesive tape not requiring release sheet and method for producing the same - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide excellent adhesion to electronic parts, particularly to metals and laminated plates as circuit board materials and semiconductor mounting materials,
Provided is a thermosetting adhesive tape which does not require a release sheet. SOLUTION: Polyvinyl butyral (component A) 100
A resin composition comprising 50 to 200 parts by weight of an epoxy compound having at least two epoxy groups in the molecule and 0.05 to 100 parts by weight of a curing agent is used as a main component with respect to parts by weight. A thermosetting adhesive tape that does not require a release sheet and a method for producing the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting adhesive tape which is used for bonding electronic parts, and particularly has excellent adhesiveness to a metal or laminated plate as a circuit board material or a semiconductor mounting material and does not require a release sheet, and its production. It is about the method.

[0002]

2. Description of the Related Art Adhesive tapes for electronic parts are used, for example, for fixing laminated boards, flexible circuit boards, lead frames, etc., and are used for joining metals to laminated board materials, metals to heat-resistant plastic films, and metals to metals. Is what you do.
With the recent development of the electronic and electrical equipment industry, it has been required to reduce the size and weight of devices for communication, industrial use, consumer use, etc., have high reliability, and simplify the mounting method. Capacities and fine pitches of printed circuits and lead frames are rapidly advancing, and higher functionality and higher reliability are required. As an example of this, there is a flexible circuit board using a light and foldable plastic film as an insulating substrate. Various adhesive resin compositions for adhering a plastic film and a metal foil have been studied so far, and examples thereof include epoxy resin, polyacrylonitrile resin, polyacrylic ester resin, phenol resin / nitrile rubber system, phenol resin / A polyvinyl acetal type, a phenolic resin / epoxy resin / polyvinyl acetal type, a phenolic resin / epoxy resin / nitrile rubber type, etc., has been researched and developed as an adhesive agent or has been put into practical use as an adhesive agent. Cast molding of such a thermosetting adhesive resin or a resin solution thereof on a support,
The adhesive tape is obtained by drying. When manufacturing such a thermosetting adhesive tape, if too much heat is applied in the drying step, curing proceeds and the adhesive strength deteriorates. Therefore, the adhesive resin is in a semi-cured state (B stage),
Therefore, the adhesiveness of the tape is strong, and when the tape is wound into a reel, it follows the inner or outer contact surface,
The adhesive layer is turned up and cannot be used. In order to prevent the above points, a method of laminating a release sheet on one side or both sides of the tape is adopted. However, using a release sheet increases costs, is not suitable from the viewpoint of resource conservation in recent years, and it may be technically difficult to lengthen the tape due to friction between the release sheets and the winding thickness being bulky. . In order to attach a release sheet to one side or both sides of a base material, an unwinder for the release sheet and a roll for laminating are required in the coating machine, which is a problem in equipment. It is desired to develop an adhesive tape that solves the problems mentioned above.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermosetting material which is excellent in adhesiveness to electronic parts, particularly as a circuit board material or a semiconductor mounting material, to a metal or a laminated plate and does not require a release sheet. The purpose of the present invention is to provide an adhesive tape.

[0004]

According to the present invention, 40 to 220 parts by weight of an epoxy compound (component B) having at least two epoxy groups in the molecule is added to 100 parts by weight of polyvinyl butyral (component A). The present invention relates to a thermosetting adhesive tape that does not require a release sheet containing a resin composition containing 0.04 to 100 parts by weight of a curing agent (component C) as a main component, and a method for producing the same.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The adhesive resin used in the present invention comprises 40 parts by weight of an epoxy compound (component B) having at least two epoxy groups in the molecule, based on 100 parts by weight of polyvinyl butyral (component A). ˜220 parts by weight and 0.04 to 100 parts by weight of a curing agent (component C).

The polyvinyl butyral (component A) used in the present invention preferably has an average degree of polymerization of 500 or more and 50 cps or more (ethanol / toluene = 1/1 (weight ratio) 10% by weight solution). When the degree of polymerization is low, the coated surface tends to be sticky and a release sheet is required. Further, it becomes difficult to obtain a self-supporting coating film, and it becomes impossible to manufacture a tape without a base material. As a concrete resin, for example, a 5% solution of acetalization degree 70 mol%, acetyl group 3 mol%, ethanol / toluene = 1/1 has a viscosity of 250 ± 50 cps at 20 ° C. and a glass transition point of 110 ° C. or higher. Polyvinyl acetal resin, which is a high degree of polymerization type, butyral group 65 ± 3
Mol%, acetyl group 3 mol% or less, viscosity of a 5% solution of 90% ethanol at 20 ° C has a viscosity of 70 to 130 cps.
Polyvinyl butyral resin, which is a high polymerization type of
Butyral group 70 mol% or more, acetyl group 4-6
A highly butyrated polyvinyl butyral resin, which is a high degree of polymerization type having a viscosity of 40 cps at 20 ° C. of a 5% solution of mol% and ethanol / toluene = 1/1, can be mentioned.

Further, excellent heat resistance is required for electronic material applications including the soldering step, and for such applications, it is desirable to use a type in which the hydroxyl groups of polyvinyl butyral resin remain in a high concentration. , Residual hydroxyl group 3
The viscosity of a 5% solution of 3 ± 3 mol%, acetyl groups of 3 mol% or less, and ethanol / toluene = 1/1 has a viscosity of 7 at 20 ° C.
Polyvinyl butyral resin of high polymerization degree of 0 to 140 cps, residual hydroxyl group 33 ± 3 mol%, acetyl group 3 mol% or less, ethanol / toluene = 1 /
Polyvinyl butyral resin, which is a high degree of polymerization type, in which the viscosity of a 5% solution of 1 at 20 ° C. is 60 to 120 cps, residual hydroxyl group 33 ± 3 mol%, acetyl group 3 mol%
20% of a 5% solution of ethanol / toluene = 1/1
High polymerization degree type polyvinyl butyral resin with viscosity of 130-200 cps at 30 ° C, residual hydroxyl group 30 ± 3
mol%, acetyl group 3 mol% or less, ethanol /
Viscosity of a 5% solution of toluene = 1/1 at 20 ° C is 70-
Polyvinyl butyral resin having a high polymerization degree of 100 cps is suitable. These can be used alone or in combination of two or more.

The epoxy compound (component B) used in the present invention is preferably solid. In the case of a liquid epoxy compound, the compounding amount has to be reduced in order to suppress the tackiness of the coated surface, which lowers the adhesion reliability after curing and is not preferable. Examples thereof include bisphenol A type diglycidyl ether, bisphenol F type diglycidyl ether, novolac type epoxy resin, and biphenyl type epoxy resin. These alone,
Alternatively, two or more kinds can be used in combination.

The epoxy compound (component B) is preferably added in an amount of 40 to 220 parts by weight based on 100 parts by weight of the polyvinyl butyral resin (component A). 220
If it is more than parts by weight, the adhesive layer after casting is soft,
When the adhesive tape is peeled from the support, the adhesive tape is deformed or cut, and the self-supporting property of the coating film is deteriorated, which is not preferable. If the amount is less than 40 parts by weight, the adhesiveness at the time of heat, the heat resistance and the like are deteriorated.

As the curing agent (component C) used in the present invention, one type or two or more types of general curing agents of epoxy compounds such as amine compounds, acid anhydrides, phenols, imidazoles and dicyandiamides are used in combination. Can be used. A phenol resin is particularly preferable. Not only the cross-linking of the epoxy compound but also the cross-linking reaction with the hydroxyl group in polyvinyl butyral can improve the adhesion reliability and heat resistance. For example, P which is a phenol resol
R-175, PR-22193, phenol novolac PR-7031A, PR-50731, PR-1
Phenolic resins such as 2686 (manufactured by Sumitomo Dures Co., Ltd.) are suitable.

The addition amount of the curing agent (component C) is 0.0 with respect to 100 parts by weight of the polyvinyl butyral resin (component A).
It is desirable to use 4 to 100 parts by weight, and more desirably 5 to 100 parts by weight. If the amount is more than 100 parts by weight, the physical properties of the cured product are deteriorated, such as foaming at the time of curing and deterioration of toughness, which is not preferable. If the amount is less than 0.04 part by weight, the curing is not completed and the adhesive strength and heat resistance decrease, which is not preferable.

The organic solvent for dissolving the resin composition is not particularly limited, but preferably has a boiling point of 120 ° C. or lower. For example, acetone as a ketone solvent,
Examples thereof include methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone.
These solvents may be used alone or in combination of two or more. Amide solvents such as N,
Since N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like have high boiling points, a high temperature is required during coating and drying, which is not preferable in that the curing reaction proceeds.

If desired, various additives such as a smoothing agent for providing surface smoothness and a defoaming agent can be added to the resin varnish obtained by dissolving the resin composition in an organic solvent. A coupling agent or an inorganic filler may be added to the resin varnish within a range that does not impair the processability and heat resistance.

In the present invention, the resin varnish is used as an adhesive tape, which is obtained by casting or coating the resin varnish,
For example, using a heat-resistant film substrate as a support, an adhesive resin layer is similarly formed on one or both sides of the support to form an adhesive tape with the support, or on a release sheet such as a roll, a metal sheet, or a polyester sheet. It can be obtained by a method of forming a film by a flow coater, a roll coater, etc., peeling it after heating and drying to obtain a substrateless adhesive tape.

The heat-resistant film base material used in the present invention comprises a polyimide resin film having a small coefficient of thermal expansion and excellent dimensional stability with respect to temperature change, flexibility and easy handling, and a resin of the present invention. Is preferable because it has excellent adhesion. In particular, a polyimide resin having a glass transition temperature of 350 ° C. or more is excellent in workability and stability in a step of drying a coating varnish.

For coating and drying the resin varnish, an apparatus in which coating equipment such as a flow coater or roll coater and a hot air drying furnace are combined can be used. After applying the resin varnish to the support, the resin varnish is guided to a hot-air drying oven and dried at a temperature and air volume sufficient to volatilize the solvent of the varnish.

The method of using the adhesive tape of the present invention is not particularly limited, but it is heated by a continuous laminating method by roll-to-roll short-time roll compression or a heat block which is cut into a predetermined shape and heated. Examples include a method of pressure bonding and adhesion. The thermosetting adhesive tape of the present invention may be used for bonding electronic components, particularly for circuit board materials and semiconductor mounting materials.

The thermosetting adhesive tape of the present invention is preferable from the viewpoint of resource saving because it does not require a release sheet, and can simplify the coating equipment and coating process. Further, since it is possible to obtain a coating film having self-supporting properties, a thermosetting adhesive tape without a substrate can be produced. Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0019]

【Example】

(Example 1) In accordance with the formulation shown in Table 1, ethanol / toluene = 1/1 (weight ratio) 900 g was added with a special polyvinyl acetal resin (KS-5, Sekisui Chemical Co., Ltd.) as component A.
(Manufactured by Mitsui Chemicals Co., Ltd.) and uniformly dissolved, and then, in 30 g of methyl ethyl ketone (MEK), Epicoat 100 which is a bisphenol A type diglycidyl ether as component B
MEK solution in which 120 g of 1 (Okaka Shell Epoxy Co., Ltd.) was added and uniformly dissolved, and methyl ethyl ketone (ME
K) PR-7031A (manufactured by Sumitomo Dures Co., Ltd.) which is an alkylphenol-modified novolac as component C in 10 g.
MEK solution in which 30 g was added and uniformly dissolved was added and stirred to obtain a resin composition varnish. This varnish was applied to one side of a polyimide film (trade name Upilex SGA, thickness 50 μm, Ube Industries, Ltd.) with a reverse roll coater to obtain an adhesive tape having an adhesive layer thickness of 30 μm. The maximum drying temperature was 110 ° C and the maximum drying time was 6 minutes. Even when the coated tape was wound with a winder, no hindrance was given to the winding process without attaching a release sheet. Further, when unrolling from the wound tape, the adhesive layer did not follow the upper surface or the lower surface of the base material and the adhesive layer was turned up. Next, this adhesive tape was pressure-bonded to a non-black-treated metallic glossy surface of a 35 μm electrolytic copper foil by a hot press having a heat block to prepare a test piece. Adhesive conditions: 200 ° C / 1 second, pressure: 4k
It was g / cm ² . The test piece was cured on a hot plate at 175 ° C / 1.5 hours. The 180 degree peel strength of this test piece was measured by a tensile tester (pulling speed: 50 mm
/ Min). At the fracture surface, the adhesive layer was cohesively broken and no foaming was observed. The thermal decomposition start temperature was measured by a differential thermogravimetric analyzer (TG / DTA, heating rate 1 using a sample obtained by curing the coated tape on a hot plate at 175 ° C. for 1.5 hours.
The results are shown in Table 1.

[0020]

[Table 1]

(* 1) KS-5: Elex K, Sekisui Chemical Co., Ltd. special polyvinylnyl acetal resin, degree of acetalization =
70mol% or more Viscosity = 250cps (Ethanol / toluene = 1/1, measured with a 5% solution using a rotary viscometer, 20 ° C) (* 2) BH-3: Elex B, Sekisui Chemical Co., Ltd. Polyvinyl Butyral resin, degree of butyralization = 65mol% Viscosity = 70-130cps (90% ethanol, measured with a rotational viscometer at 5% solution, 20 ° C) (* 3) BX-1: Elex B, Sekisui Chemical ( Polyvinyl butyral resin manufactured by K.K., residual hydroxyl content = 33mol%, viscosity = 70-140cps (Ethanol / toluene = 1/1, measured with a 5% solution using a rotary viscometer, 20 ° C) (* 4) Epicate 1001: Bisphenol A type diglycidyl ether manufactured by Yuka Shell Epoxy Co., Ltd. Softening point = 64 to 74 ° C, Epoxy equivalent = 450 to 500 g / eq (* 5) YX-4000H: Biphenyl epoxy resin Oilized shell epoxy (stock) ) Melting point = 105 ° C, Epoxy equivalent = 187-192g / eq (* 6) PR-7031A: Alkylphenol-modified Rack resin, Sumitomo Durez Co. mp = 100 ° C., gel time (sec / 165 ℃) = 25 (* 7) PR-175: alkylphenol modified resole resin,
Sumitomo Dures Co., Ltd. Melting point = 60 ° C, gelation time (sec / 165 ° C) = 25

(Examples 2 to 4) In the same manner as in Example 1, resin varnishes were prepared according to the formulation shown in Table 1, and adhesive tapes were prepared and evaluated.

Example 5 According to the formulation of Table 2, the component A was added to 600 g of ethanol / toluene = 1/1 (weight ratio).
100 g of a special polyvinyl acetal resin (KS-5, manufactured by Sekisui Chemical Co., Ltd.) was added as a solution and uniformly dissolved, and then 30 g of methyl ethyl ketone (MEK) was added to Epicoat 1001 which is a bisphenol A type diglycidyl ether (B). Yuka Shell Epoxy Co., Ltd.) 12
MEK solution in which 0 g was added and uniformly dissolved, and MEK solution in which 10 g of methyl ethyl ketone (MEK), 30 g of PR-7031A (manufactured by Sumitomo Dures Co., Ltd.), which is an alkylphenol-modified novolac, was added as Component C and uniformly dissolved were added. The resin composition varnish was obtained by stirring. Apply this varnish to a biaxially stretched polyester film (trade name: Diamond foil, thickness: 50 μm, manufactured by Mitsubishi Rayon Co., Ltd.) with a reverse roll coater, and after drying, peel the adhesive layer from the polyester film as a base material. The tape obtained in 1. was wound with a winder to obtain a single-layer adhesive tape having a thickness of 75 μm. The maximum drying temperature was 120 ° C. and the maximum drying time was 7.5 minutes. Even when the coated tape was wound with a winder, no hindrance was given to the winding process, and the tension applied during winding did not cause the single-layer adhesive tape to stretch. Further, when unrolling from the wound tape, the adhesive layer did not follow the upper surface or the lower surface of the base material and the adhesive layer was turned up. The thermal decomposition start temperature is 175 ° C /
A differential thermogravimetric analyzer (TG / DTA, heating rate 10 ° C./using a single layer sample cured on a hot plate for 1.5 hours
min, under air) and the results are shown in Table 2.
The adhesive strength is a polyimide base material as in Examples 1 to 4,
Tape samples were prepared according to the coating conditions shown in Table 2. As in the previous case, this adhesive tape was pressure-bonded to a 35 μm electrolytic copper foil, which had not been subjected to black treatment, on a metallic glossy surface with a hot press having a heat block to prepare a test piece. Adhesion condition is 20
The temperature was 0 ° C./1 second and the pressure was 4 kg / cm ² . The test piece was cured on a hot plate at 150 ° C. for 1.5 hours. The 180 degree peel strength of this test piece was measured by a tensile tester (pulling speed: 50 mm / min). At the fracture surface, the adhesive layer was cohesively broken and no foaming was observed.

[0024]

[Table 2]

(Examples 6 to 8) In the same manner as in Example 5, resin varnishes were prepared according to the formulations shown in Table 2 to prepare and evaluate adhesive tapes.

(Comparative Examples 1 to 3) According to the formulations shown in Table 3, test pieces were prepared in the same manner as in Example 2.

[0027]

[Table 3]

(* 8) PNR-1H: acrylonitrile-
Butadiene rubber, manufactured by Nippon Synthetic Rubber Co., Ltd. Mooney viscosity = 70ML1 + 4 (100 ° C) Acrylonitrile content = 27wt% Bond carboxyl group content = 4.0mol%

From the results shown in Table 3, it can be confirmed that the component A is a polyvinyl butyral resin, which exhibits non-adhesiveness at room temperature, resulting in a thermosetting adhesive tape which does not require a release sheet. It can be seen that if any one of C and C is missing, problems such as lack of self-supporting property or lack of adhesiveness at the time of heating occur, and expected physical properties are not expressed. From the above examples, the present invention shows that a thermosetting adhesive tape which does not require a release sheet having excellent adhesiveness and heat resistance can be obtained, and a single-layer thermosetting adhesive tape without a base material.

[0030]

EFFECTS OF THE INVENTION The thermosetting adhesive tape of the present invention is preferable from the viewpoint of resource saving in that a release sheet is not required, and the coating equipment and coating process can be simplified. Further, since it is possible to obtain a coating film having self-supporting properties, a thermosetting adhesive tape without a substrate can be produced. Since it has excellent adhesiveness to metals and laminated plates as usages, it can be advantageously used for electronic parts bonding applications, particularly circuit board materials and semiconductor mounting materials.

Claims (3)

[Claims] 1. Polyvinyl butyral (component A) 100
40 to 220 parts by weight of an epoxy compound (component B) having at least two epoxy groups in the molecule based on parts by weight.
A thermosetting adhesive tape which does not require a release sheet containing a resin composition containing 0.04 to 100 parts by weight of a curing agent (component C) as a main component. 2. A method for producing a thermosetting adhesive tape, which does not require a release sheet formed by casting the solution of the resin composition according to claim 1 on one side or both sides of a support. 3. A baseless thermosetting method which does not require a release sheet obtained by casting the solution of the resin composition according to claim 1 on a support, and then drying after casting. Of producing a flexible adhesive tape.