JP2000109645A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition exhibiting high adhesive strength to a polyimide film and having excellent heat resistance and low water absorptivity by incorporating a polyimide comprising an ester acid dianhydride and a diamine with an epoxy resin. SOLUTION: This composition comprises a polyimide comprising an ester acid dianhydride represented by formula I and a diamine represented by formula II, desirably, a diamine represented by formula III and an epoxy resin. In the formulae, X is an aromatic-ring-containing divalent group; Y is -C(O)-, SO2-, -O-, -S-, -(CH2)m-, -NHCO-, -C(CH3)2-, -C(CF3)2-, -C(O)O-, or a single bond; and m and n are 1-5. It is desirable that this composition has a water absorptivity after being cured. The epoxy resin used is exemplified by a (halogenated) bisphenol epoxy resin or a phenol novolac epoxy resin and is used in an amount of, desirably, 1-50 pts.wt. per 100 pts.wt. polyimide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition which can be adhesively cured at a relatively low temperature, is soluble in a solvent, and has excellent heat resistance and adhesiveness. The resin composition of the present invention comprises a flexible printed circuit board, TAB (Tape Automated).
It is useful as an adhesive having excellent heat resistance and adhesiveness used in bonding tapes, composite lead frames, laminated materials, and the like.

[0002]

2. Description of the Related Art In recent years, electronic devices have become more sophisticated and more sophisticated.
With miniaturization progressing, there has been a demand for miniaturization and weight reduction of electronic components used accordingly. Therefore, a semiconductor element packaging method and a wiring material or a wiring component for mounting the same have been required to have higher density, higher function, and higher performance. In particular, semiconductor packages, COL and LOC packages, MCM (Mul
There is a need for a material exhibiting good adhesion that can be suitably used as a high-density packaging material such as a ti chip module), a printed wiring board material such as a multilayer FPC, and an aerospace material.

Heretofore, in semiconductor packages and other mounting materials, adhesives such as acrylic, phenolic, epoxy and polyimide have been known as adhesives exhibiting good mechanical properties, heat resistance and insulating properties. .

However, phenol-based and epoxy-based adhesives have excellent adhesiveness, but are inferior in flexibility. There has been a problem that a flexible acrylic adhesive has low heat resistance.

[0005]

In order to solve these problems, polyimide is used. Polyimide is excellent in heat resistance among various organic polymers, and is therefore widely used in the fields of space and aviation to the field of electronic communication, and is also used as an adhesive material. However, a polyimide-based adhesive having high heat resistance requires a high temperature of about 300 ° C. and a high pressure for bonding, and the adhesive strength is not so high. Also, conventional polyimide adhesives have high water absorption,
For example, when a lead frame using this polyimide-based adhesive is immersed in a solder bath, there has been a problem that blisters and the like are easily generated.

[0006]

SUMMARY OF THE INVENTION The present invention has a low water absorption rate, excellent solder heat resistance, and excellent heat resistance and adhesiveness.
An object of the present invention is to provide a resin composition that can be bonded at a low temperature of 0 ° C. or lower.

The gist of the present invention is that the general formula (1)

[0008]

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An ester dianhydride represented by the formula (2):
Chemical 5

[0010]

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A resin composition comprising a polyimide composed of a diamine and an epoxy resin is described.

In the diamine represented by the general formula (2), particularly, the diamine represented by the general formula (3)

[0013]

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The present invention relates to the above resin composition characterized by the following.

[0015] The present invention also relates to the resin composition, wherein the water absorption after curing is 1.5% or less.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compound represented by the general formula (1):
X represents a divalent group containing an aromatic ring. ) And a diamine of the formula (2) or (3).

The acid dianhydride used in the polyimide composition according to the present invention has the general formula (1)

[0018]

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(In the formula, X is a divalent organic group.) It is essential to use an ester dianhydride represented by the formula:

The polyimide composition using the ester dianhydride represented by the general formula (1) has excellent low heat absorption and therefore has excellent solder heat resistance.

The general formula (2)

[0022]

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(Where Y is -C (= O)-, -SO
_{2 -, - O -, -} S -, - (CH 2) m -, - NHCO
_{-, - C (CH 3)} 2 -, - C (CF 3) 2 -, - C
(= O) O- or a bond. m and n are 1 or more and 5
It is essential to use a diamine represented by the following integer:

In the general formula (2), a plurality of Y
May be the same or two or more substituents. Further, hydrogen of each benzene ring can be appropriately substituted with various substituents within a range that can be considered by those skilled in the art. Examples thereof include a halogen group such as a methyl group, an ethyl group, and Br and Cl, but are not limited to these substituents.

Furthermore, the present inventors have found that the amino group of the diamine represented by the general formula (2) is bonded to the meta position, so that the solubility of the polyimide composition using the same in a solvent is increased. And paid attention to exhibiting excellent usefulness when used as an adhesive.

Specifically, as a diamine, in the general formula (2), particularly, an amino group is represented by the general formula (3):

[0027]

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(Where Y is -C (= O)-, -SO
_{2 -, - O -, -} S -, - (CH 2) m -, - NHCO
_{-, - C (CH 3)} 2 -, - C (CF 3) 2 -, - C
(= O) O- or a bond. m and n are 1 or more and 5
It is the following integer. As shown in ()), it is preferably in the meta position. By having an amino group at the meta position,
The solubility of the resulting polyimide in an organic solvent is better, and the processability is excellent.

The diamine represented by the general formula (2) or (3) can be used alone or in combination of two or more.

The polyimide used in the resin composition according to the present invention is obtained by dehydrating and cyclizing a polyamic acid polymer as a precursor thereof. This polyamic acid solution uses substantially equimolar amounts of the ester dianhydride represented by the general formula (1) and one or more diamine components represented by the general formula (2) or (3). And polymerized in an organic polar solvent.

This polyimide is first prepared by reacting a compound represented by the general formula (2) and / or
Or one or more diamines represented by the general formula (3),
An acid dianhydride selected from ester acid dianhydrides represented by the general formula (1) is dissolved or diffused in an organic polar solvent to obtain a polyamic acid polymer solution.

As for the order of adding each monomer, the general formula (1) is added to an organic polar solvent first, and the above-mentioned general formula (2) and / or general formula (3) as a diamine component is added. It may be a solution of a polyamic acid polymer.

Examples of the organic polar solvent used in the reaction for producing the polyamic acid solution include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide;
Formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide; acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide; pyrrolidone solvents such as N-methyl-2-pyrrolidone; phenol , O-, p-, m-, or p-cresol, xinol, halogenated phenol,
Examples include phenol-based solvents such as catechol, and hexamethylphosphoramide and γ-butyrolactone. Further, if necessary, these organic polar solvents can be used in combination with an aromatic hydrocarbon such as xylene or toluene.

The polyamic acid polymer obtained above is dehydrated and ring-closed by a thermal or chemical method to obtain a polyimide. As the imidation method, any of a thermal method of dehydrating the polyamic acid solution by heat treatment and a chemical method of dehydrating using a dehydrating agent are used.

In the method of thermally dehydrating and cyclizing, the solvent of the above polyamic acid solution is evaporated, and in the method of chemically dehydrating and cyclizing the polyamic acid solution, a stoichiometric or more dehydrating agent and a catalyst are added to the polyamic acid solution, and an organic solvent is added. Is evaporated and imidized while heating and drying in both the thermal method and the chemical method to obtain a polyimide constituting the resin composition according to the present invention. The evaporation of the organic solvent is preferably performed at a temperature of 150 ° C. or less for a time period of about 5 minutes to 90 minutes. The heating temperature for imidization is appropriately selected from room temperature to about 250 ° C., and the temperature is gradually increased. Examples of the dehydrating agent by a chemical method include aliphatic acid anhydrides such as acetic anhydride, and aromatic acid anhydrides. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine and isoquinoline.

Among them, according to the chemical method, the heating temperature is low, and the time required for imidization is shortened.
This is preferable because it does not affect the mechanical properties such as elongation or tensile strength of the resulting polyimide. Combinations with thermal and chemical methods can also be used.

The polyimide obtained above has a low water absorption and a glass transition temperature at a relatively low temperature, so that a polyimide resin composition which can be used as an excellent adhesive material capable of low water absorption and low temperature bonding is used. It can be used as a constituent. Therefore, when the resin composition according to the present invention is cured, an excellent low water absorption of 1.5% or less, preferably 1.3% or less, particularly preferably 1.0% or less can be exhibited. .

The resin composition according to the present invention is characterized in that an epoxy resin is mixed with a polyimide comprising the above ester dianhydride and a diamine. By using the epoxy resin, the resin composition according to the present invention can impart more excellent adhesiveness to the excellent properties such as heat resistance and low water absorption of the polyimide used in the present invention.

The epoxy resin used in the present invention includes bisphenol epoxy resin, halogenated bisphenol epoxy resin, phenol novolak epoxy resin, halogenated phenol novolak epoxy resin, alkylphenol novolak epoxy resin,
Polyphenol-based epoxy resin, polyglycol-based epoxy resin, cycloaliphatic epoxy resin, cresol novolak-based epoxy resin, glycidylamine-based epoxy resin, urethane-modified epoxy resin, rubber-modified epoxy resin, epoxy-modified polysiloxane, and the like can be used.

The mixing ratio of the epoxy resin is polyimide 1
It is desirable to add 1 to 50 parts, preferably 5 to 30 parts with respect to 00 parts. If the amount is too small, the adhesive strength is low, and if it is too large, the flexibility and heat resistance are poor.

Further, if necessary, commonly used epoxy curing agents such as acid dianhydrides, amines, imidazoles, etc., accelerators and various coupling agents may be used in combination as required. obtain. Further, a thermosetting resin other than the epoxy resin, a phenol resin, a cyanate resin, or the like may be used.

Conventional polyimide adhesives have insufficient adhesion to metals such as copper foil and resin films such as polyimide, and have been more difficult to mix with epoxy resins due to their poor solubility. The resin composition according to the present invention has good adhesiveness to a metal foil such as a copper foil or a polyimide film, and also has a property that its solubility in an organic solvent is good. Excellent in nature. For example, a solution obtained by imidizing a polyamic acid polymer solution can be used directly in the form of a sheet or in the form of a varnish. Further, it can be used in the form of a solid and then dissolved in an organic solvent as appropriate to be used as a varnish.

There are various methods of using the resin composition of the present invention as an adhesive material within a range that can be carried out by a person skilled in the art. Can be used as an adhesive. Further, the resin composition of the present invention is impregnated as a varnish in glass cloth, glass mat, aromatic polyamide fiber cloth, aromatic polyamide fiber mat, etc., semi-cured resin, and used as a fiber-reinforced sheet adhesive. It is also possible.

Further, the resin composition of the present invention can be dissolved in a solvent and used as it is as a varnish. Specifically, a varnish in which the resin composition is dissolved is applied to one or both surfaces of the polyimide film, and dried, and copper foil / aluminum foil,
For example, a metal foil such as a 42 alloy foil, a polyimide film, a printed circuit board, or the like may be bonded by heating and pressing. In this case, the type of the polyimide film is not particularly limited. The organic solvent to be dissolved is not particularly limited, but is preferably an organic polar solvent used for a reaction for producing a polyamic acid solution. For example, sulfoxide solvents such as dimethylsulfoxide and diethylsulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, and acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide , A pyrrolidone solvent such as N-methyl-2-pyrrolidone, phenol,
Examples include o-, p-, m-, or p-cresol, xinol, halogenated phenols, phenolic solvents such as catechol, or hexamethylphosphoramide, γ-butyrolactone, and the like. Further, if necessary, these organic polar solvents may be used in combination with an aromatic hydrocarbon such as xylene or toluene, but the present invention is not limited thereto. The bonding condition in this case may be any bonding condition necessary and sufficient for bonding and curing, and specifically, a heating temperature of 150 ° C.
~ 250 ° C, pressure 0.1 ~ 10MPa, heating time 5 ~ 2
It is preferable to heat and pressurize under the condition of about 0 minutes.

The resin composition according to the present invention obtained as described above has characteristics that can be suitably used for electronic devices, particularly, flexible printed circuit boards, TAB tapes, composite lead frames, laminated materials, and the like. That is, specifically, it shows an excellent low water absorption of 1.5% or less, preferably 1.3% or less, particularly preferably 1.0% or less, and has excellent solder heat resistance and heat resistance. It has excellent adhesiveness and can be bonded at a temperature of about 250 ° C. or less when used as an adhesive.

[0046]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples, but these Examples illustrate the present invention.
It is not meant to be limiting. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention.

Example 1 In a glass flask having a capacity of 500 ml, 280 g of dimethylformamide (hereinafter referred to as DMF) and 3,3'-bis (aminophenoxyphenyl) propane (meta type: hereinafter referred to as BAPP-M). ) 0.1487 mol is charged and dissolved under stirring in a nitrogen atmosphere. Further, the solution was stirred while cooling the solution with ice water under a nitrogen-substituted atmosphere in the flask, so that 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ′,
4,4'-tetracarboxylic dianhydride (hereinafter referred to as ESDA
That. ) 0.1487 mol was gradually added while paying attention to the viscosity. When the viscosity reached 1500 poise, the addition of ESDA was stopped to obtain a polyamic acid polymer solution.

280 g of dimethylformamide (hereinafter referred to as DMF) is placed in a 500-ml glass flask.
3,3'-bis (aminophenoxyphenyl) propane (meta type: hereinafter referred to as BAPP-M) 0.148
7 mol is charged and dissolved under a nitrogen atmosphere. Further, the solution is stirred while cooling the solution with ice water under a nitrogen-substituted atmosphere in the flask, and 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ′, 4,4′-tetracarboxylic dianhydride (Hereinafter referred to as ESDA) 0.14
87 mol was gradually added while paying attention to the viscosity. When the viscosity reached 1500 poise, the addition of ESDA was stopped to obtain a polyamic acid polymer solution.

To this polyamic acid solution, DMF150,
After adding 35 g of β-picoline and 60 g of acetic anhydride and stirring for 1 hour, the mixture was further stirred at 100 ° C. for 1 hour and imidized. Thereafter, the solution was dripped little by little into methanol stirred at high speed. The filamentous polyimide precipitated in methanol was dried at 100 ° C. for 30 minutes, pulverized with a mixer, washed with Soxhlet with methanol, and dried at 100 ° C. for 2 hours to obtain a polyimide powder.

20 g of the above-obtained polyimide powder, 5 g of bisphenol A epoxy resin; Epicoat 828 (manufactured by Yuka Shell Co.), and 2-ethyl- as a curing accelerator
0.015 g of 4-methylimidazole in 83 g of DMF
Was dissolved. The obtained varnish was cast on a glass plate,
After drying at 00 ° C for 10 minutes, it was peeled off from the glass plate, fixed to an iron frame, further dried at 150 ° C for 20 minutes, and had a thickness of 25 µm.
Sheet was obtained. The obtained sheet was coated with a polyimide film (Apical 50AH, manufactured by Kanegabuchi Chemical Industry Co., Ltd.) and a thickness of 25 μm.
m at a temperature of 200 ° C and a pressure of 3 MPa.
The mixture was heated and pressed for 0 minutes to obtain a copper-clad flexible laminate.

(Example 2) The varnish obtained in Example 1 was applied to a polyimide film (Apical 50AH, manufactured by Kanegabuchi Chemical Industry Co., Ltd.), and then 100 ° C. for 10 minutes and 150 minutes.
The resultant was dried by heating at 20 ° C. for 20 minutes to form an adhesive layer having a thickness of 25 μm. The obtained single-sided polyimide film with an adhesive layer and a 25 µm copper foil were heated at a temperature of 200 ° C and a pressure of 3 MPa for 20 minutes to obtain a copper-clad flexible laminate.

Example 3 20 g of the polyimide powder obtained in Example 1, glycidylamine type epoxy resin; TETR
5 g of AD-C (Mitsubishi Gas Chemical Co., Ltd.) to 83 g of D
Dissolved in MF. The resulting varnish was cast on a glass plate, dried at 100 ° C. for 10 minutes, peeled off from the glass plate, fixed on an iron frame, and dried at 150 ° C. for 20 minutes to obtain a sheet having a thickness of 25 μm. The obtained sheet was sandwiched between a polyimide film (Apical 50AH, manufactured by Kanegabuchi Chemical Industry Co., Ltd.) and a copper foil having a thickness of 25 μm.
Heating and pressurizing was performed at a pressure of 3 MPa for 20 minutes to obtain a copper-clad flexible laminate.

(Example 4) Diamine component was 4,4'-
(1,3-phenylenebis (1-methylethylidene))
A polyamic acid polymer solution was obtained and a polyimide powder was obtained in the same manner as in Example 1 except that bisaniline (para-type) was used.

A copper-clad flexible laminate was obtained from the above-obtained polyimide powder in the same manner as in Example 1.

Example 5 A polyamic acid polymer solution was obtained in the same manner as in Example 1 except that the diamine component was changed to 4,4'-bis (aminophenoxyphenyl) propane (para type). I got

A copper-clad flexible laminate was obtained from the polyimide powder obtained in the same manner as in Example 1.

Example 6 The diamine component was replaced with 3,3'-bis (aminophenoxyphenyl) sulfone (BAPS)
A polyamic acid polymer solution was obtained and a polyimide powder was obtained in the same manner as in Example 1 except that -M) was used.

Using the polyimide powder obtained above, a copper-clad flexible laminate was obtained in the same manner as in Example 1.

(Comparative Example 1) A glass flask having a capacity of 500 ml was charged with 0.1487 mol of 3,3'-bis (aminophenoxyphenyl) propane (hereinafter referred to as BAPP-M) in 280 g of dimethylformamide (DMF) under a nitrogen atmosphere. Dissolve with stirring. Further, 0.1487 mol of benzophenonetetracarboxylic dianhydride (hereinafter referred to as BTDA) was gradually added while cooling the solution with ice water and stirring while replacing the atmosphere in the flask with nitrogen while paying attention to the viscosity. 1500poise viscosity
When BTDA was reached, the addition of BTDA was stopped to obtain a polyamic acid polymer solution.

To this polyamic acid solution were added 150 g of DMF,
After adding 35 g of β-picoline and 60 g of acetic anhydride and stirring for 1 hour, the mixture was further stirred at 100 ° C. for 1 hour and imidized. The solution was then dripped little by little into methanol stirred at high speed. The filamentous polyimide precipitated in methanol was dried at 100 ° C. for 30 minutes, pulverized with a mixer, washed with Soxhlet with methanol, and dried at 100 ° C. for 2 hours to obtain a polyimide powder.

20 g of the polyimide powder obtained above, 5 g of Epicoat 828 (manufactured by Yuka Shell Co., Ltd.), and 2-ethyl-
0.015 g of 4-methylimidazole in 83 g of DMF
Was dissolved. The obtained varnish was cast on a glass plate,
After drying at 00 ° C for 10 minutes, it was peeled off from the glass plate, fixed to an iron frame, further dried at 150 ° C for 20 minutes, and had a thickness of 25 µm.
Sheet was obtained. The obtained sheet was sandwiched between a polyimide film (Apical 50AH, manufactured by Kanegabuchi Chemical Industry Co., Ltd.) and a copper foil of 25 μm, and heated and pressed at a temperature of 200 ° C. and a pressure of 3 MPa for 20 minutes to obtain a copper-clad flexible laminate.

Comparative Example 2 20 g of the polyimide powder obtained in Example 1 was dissolved in 83 g of DMF. The obtained varnish was cast on a glass plate, dried at 100 ° C. for 10 minutes, peeled off from the glass plate, fixed to an iron frame, and further fixed at 150 ° C. for 2 minutes.
After drying for 0 minutes, a sheet having a thickness of 25 μm was obtained. The obtained sheet was sandwiched between a polyimide film (Apical 50AH, manufactured by Kanegabuchi Chemical Industry Co., Ltd.) and a copper foil of 25 μm, and a temperature of 200 μm.
Heating and pressurizing was performed at a temperature of 3 ° C. and a pressure of 3 MPa for 20 minutes to obtain a copper-clad flexible laminate.

Comparative Example 3 10 g of Platabond M1276 (copolymer nylon, manufactured by Nippon Rilsan Co., Ltd.), 20 g of Epicoat 828 (manufactured by Yuka Shell Co., Ltd.), and 1 g of diaminodiphenylsulfone were dissolved in 83 g of DMF. The resulting varnish was cast on a glass plate, dried at 100 ° C. for 10 minutes, peeled off from the glass plate, fixed on an iron frame, and dried at 150 ° C. for 20 minutes to obtain a sheet having a thickness of 25 μm. The obtained sheet is placed on a polyimide film (Apical 5).
0AH, manufactured by Kanegabuchi Chemical Industry Co., Ltd.) and a copper foil of 25 μm, and heated and pressed at a temperature of 200 ° C. and a pressure of 3 MPa for 20 minutes.
A copper-clad flexible laminate was obtained.

The peel strength and solder heat resistance of the flexible copper-clad laminates obtained in the above Examples and Comparative Examples were evaluated. The water absorption of each adhesive sheet was also evaluated. Table 1 shows the results.

[0065]

[Table 1]

The peeling strength was measured according to JISC 64
81. Regarding the solder heat resistance, the external appearance evaluation when immersed in a 260 ° C. solder bath for 10 seconds was evaluated as good when there was no blister.

The water absorption was calculated by measurement based on ASTM D570. Film at 150 ° C for 30
Despite dried weight as W _1, and the weight of those wiped surface after soaked in distilled water for 24 hours and W ₂ minutes,
It was calculated by the following equation. Water absorption (%) = (W ₂ −W ₁ ) ÷ W ₁ × 100

[0068]

The resin composition of the present invention can be bonded at a temperature of about 250 ° C. when used as an adhesive. Unlike conventional heat-resistant adhesives, it does not require high temperatures for bonding, exhibits high adhesive strength to polyimide films, and maintains high adhesive strength up to high temperatures. Furthermore, since it has a low water absorption of 1.5% or less, it has solder heat resistance that does not cause blistering or the like when immersed in a solder bath.

Claims (3)

[Claims] 1. A compound of the general formula (1) (Wherein X represents a divalent group containing an aromatic ring) and an ester dianhydride represented by the general formula (2): (Wherein, Y is, -C (= O) -, - SO 2 -, - O-,
_{-S -, - (CH 2)} m -, - NHCO -, - C (CH
_{3) 2 -, - C (} CF 3) 2 -, - C (= O) O-, or indicate binding. m and n are integers of 1 or more and 5 or less. A) a resin composition comprising a polyimide comprising the diamine and an epoxy resin. 2. The diamine represented by the general formula (2) is converted into a compound represented by the general formula (3): (Wherein, Y is -C (= O) -, - SO 2 -, - O -, -
_{S -, - (CH 2)} m -, - NHCO -, - C (C
H ₃ ) ₂ —, —C (CF ₃ ) ₂ —, —C (＝ O) O— or a bond, and m and n are integers of 1 or more and 5 or less. 2. The resin composition according to claim 1, wherein 3. The resin composition according to claim 1, wherein the water absorption after curing is 1.5% or less.