JPH02151681A - Heat-resistant adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in heat resistance, humidity resistance, electrical properties and workability by mixing a solvent-soluble acyclic polyimide resin with a specified thermosetting resin. CONSTITUTION:5-70wt.% solvent-soluble acyclic polyimide resin of formula l [wherein R<1> is a tetracarboxylic acid residue based on formula II and containing formula III or IV; R<2> is a diamine residue based on formula V or VI and containing formula VII or VIII; R<3-6> are each a 1-4C alkyl; X is a biva lent group such as -CH2-, -O-, -SO2-; -C(CH3)2-, -C(CF3)2- or -S-, R<7> and R<9> are each a bivalent organic group; R<8> and R<10> are each a monovalent organic group; n is an integer >=2; and p and q are each an integer >=1] is mixed with 95-30wt.% thermosetting resin essentially consisting of an N,N'-bisimide com pound of an unsaturated dicarboxylic acid of the formula IX (wherein R<11> is a 2 C or higher bivalent group; and R<12> is a C-C double bond-containing bivalent group), an aminophenol of formula X (wherein R<13> is H, a halogen atom or an alkyl), an aniline of formula XI (wherein R<14> and R<15> are each H, a halogen atom or an active hydrogen-free organic group) and a cure accelerator.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a polyimide-based heat-resistant adhesive composition that has excellent heat resistance, moisture resistance, adhesiveness, electrical properties, and workability. .

(Prior Art) In recent years, as electronic devices have become denser, lighter, thinner, and smaller, demand for flexible printed wiring boards (FPC) has increased as a lightweight wiring board that allows three-dimensional free wiring. In particular, film-like double-sided adhesive tapes are used in polyimide film-based FPCs, but the adhesive is used at high temperatures (2.
In addition to being required to have adhesive strength that can withstand temperatures of 60 to 300°C, it is also required to have film-forming ability as a double-sided adhesive tape, be easily B-staged, and have good storage stability. However, it has been extremely difficult to achieve a combination of adhesive strength to the base polyimide film, heat resistance, and workability.

Conventionally, adhesives for FPCs were nitrile rubber-based (Japanese Patent Application Laid-open No. 5
1-135936, JP-A-57-3877), polyamide-based (JP-A-54-125285), polyester-based (JP-A-50-16806, JP-A-54-744)
A number of materials have been proposed, such as No. 1), polyacrylic materials, etc.
However, at present, none of these tapes has sufficient adhesive strength at high temperatures and also has the functionality of a double-sided adhesive tape. On the other hand, although polyimide adhesives have excellent adhesion and heat resistance, the bonding temperature is 250°C or higher and workability is often poor [Electronic Materials Tsuru, No.
10. p35 (1987)], a system in which a polymer of a bismaleimide compound and an aminophenol is blended with an organic solvent-soluble polyimide has also been proposed, but it has the drawback of high hygroscopicity.

(Problems to be Solved by the Invention) The purpose of the present invention has been made in view of the above circumstances, and
The object of the present invention is to provide a heat-resistant adhesive composition that has excellent heat resistance, moisture resistance, adhesiveness, electrical properties, storage stability, and workability, and is highly practical.

[Structure of the Invention] (Means for Solving the Problems) As a result of intensive research aimed at achieving the above object, the present inventors have developed a solvent-soluble chain polyimide resin and a specific thermosetting resin, which will be described later. The present invention has been completed based on the discovery that the above object can be achieved by a composition with the following.

That is, the present invention provides (A> general formula (wherein, a tetracarboxylic acid residue is a diamine residue containing , X is 10H2-0, 30
2, C(CH3) 2- -C(CF3)2- or -S- divalent group, R',
R' has only two organic groups, Rg, R'. represents a monovalent organic group, n represents an integer of 2 or more, p and q represent an integer of 1 or more,
5 to 70% by weight of a solvent-soluble chain polyimide resin represented by the formula (respectively represented), and (B) (a) - formula (wherein R'' represents a divalent group having at least 2 carbon atoms, (R12 each represents a divalent group containing a double bond between carbon atoms) and (b) an N,N'-bisimide compound of an unsaturated dicarboxylic acid represented by the formula (A) solvent-soluble compound used in the present invention. The chain polyimide resin is an aminophenol represented by the general formula (in which R'' represents a hydrogen atom, a halogen atom, or an alkyl group), and a tetracarboxylic acid whose main components are (C)-formula%. (However, in the formula, R″IR′5 is a hydrogen atom, a halogen atom,
or an organic group not containing active hydrogen) and (d) a curing accelerator as essential components.
5 to 30% by weight This is a heat-resistant adhesive composition.

The present invention will be explained in detail below.

It is produced by reacting with a diamine whose main component is Tetracarboxylic acids used herein include their anhydrides and lower alkyl esters. Specific compounds of these main component tetracarboxylic acids are:
For example, 3.3', 4,4'-benzophenonetetracarboxylic dianhydride may be mentioned. Also, 3.3'
, 4.4'-benzophenonetetracarboxylic dianhydride, in addition to 3.3
', 4,4'-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride can be used.

Further, as the diamine as the main component, for example, 33'-
Dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3.3', 5.5'-tetraethyl-4°4'-diaminodiphenylmethane, 3.3'-dimethyl-44'-diaminodicyclohexylmethane ,3
．． 3'-dimethoxy-4,4'-diaminodiphenylmethane, 3.3'-jethoxy-4,4'-diaminodiphenylmethane, 3.3'-diethyl-4,4'-diaminodiphenyl ether, 3,3'-jethoxy- 4,4
'-Diamino diphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenylsulfone, 3,3'-
Diethyl-4,4'-diaminodiphenylsulfone, 3
．． 3'-dimethoxy-4,4'-diaminodiphenylsulfone, 3,3'-jethoxy-4'4'-diaminodiphenylsulfone, 3,3'-dimethyl-44'-diaminodiphenylpropane, 3,3'-diethyl -4,4
'-Diaminodiphenylpropane, 3゜3'-dimethoxy-4,4'-diaminodiphenylpropane, 3,3
'-Jetoxy-4,4'-diaminodiphenylpropane, 3,3'-dimethyl-4,4'-diaminodiphenyl sulfide, 3,3'-diethyl-4,4'-diaminodiphenyl sulfide, 3.3 '-dimethoxy-
4,4'-diaminodiphenyl sulfide, 3.3'
-jetoxy-4,4'-diaminodiphenyl sulfide, 4,4'-dimethyl-5,5'-diaminodiphenyl hexafluoropropane, etc., and these can be used alone or in a mixture of two or more. . Also,
In an amount within the range of improving solvent solubility and metal adhesion, 1
．． 3-bis(γ-aminopropyl) -1,1,3゜3
-tetramethyldisiloxane, etc. can be used.

The thermosetting resin (B) used in the present invention essentially contains (a) an N,N'-bisimide compound of an unsaturated dicarboxylic acid, (b) an aminophenol, (C) an aniline, and (d) a curing accelerator. It is an ingredient.

(a) As the N,N'-bisimide compound, the following -
Use one having the i formula.

However, in the formula, R'' has at least 2 carbon atoms.
R12 represents a divalent group containing a double bond between carbon atoms, that is, R'' represents a linear or branched alkylene group, a cyclo group having a ring of 5 to 6 carbon atoms, Including alkylene group, divalent heterocyclic group containing at least one oxygen, nitrogen or sulfur atom, phenylene group or divalent polycyclic aromatic group -NHCO--NR''-
Examples include a plurality of benzene groups and alicyclic groups bonded by -8iR''R''- or -SO,-. R" and R" here are an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having a ring having 5 to 6 carbon atoms,
Represents a phenyl group.

Examples of R12, that is, a divalent group containing a double bond between carbon atoms, include maleic acid residues, citraconic acid residues, and tetrahydrophthalic acid residues. Therefore, specific examples of N,N'-bisimide compounds of unsaturated dicarboxylic acids that satisfy the above-mentioned conditions of R" and R" include the following. For example, maleic acid N,
N'-4,4'-diphenylmethane bisimide, maleic fiN, N''-414'-diphenyl ether bisimide, maleic i1N, N'-varaphenylene bisimide, maleic acid N, N'-benzidine bisimide, maleic acid N , N'-methaxylene bisimide, maleic acid N.

N'-1,5-naphthalene-bisimide, maleic acid N
.

N'-4,4''-diphenylsulfone-bisimide, N maleic acid, N'-2,2'-4,4'-dimethylene-cyclohexane-bisimide, N maleic acid, N'-
44'-dicyclohexyl-methane bisimide, malein #! iN, N'-4,4'-diphenylcyclohexane-bisimide, N maleic acid, N'-4,4'-diphenyl-phenylamine-bisimide, N maleic acid
, N'-4,4'-diphenyl-diphenylsilane-
Bisimide, maleic acid N, N'-4,4'-diphenyl sulfur-bisimide, maleic acid N, N'-2,2
'-(4,4-diphenyl)-propane-bisimide,
Examples include maleic acid N, N'-metaphenylene-bisimide, maleic acid N, N"-3,3'-(N,N'-metaphenylene-bisbenzamide) bisimide, and these may be used alone or in combination of two or more. Can be used in combination.

As the next component of the thermosetting resin (b) aminophenol, one having the following general formula is used.

However, in the formula, R" represents a hydrogen atom, a halogen atom, or an alkyl group. Examples of specific compounds include O-aminephenol, 1-aminephenol, p-aminophenol, 2-amino-4-chlorophenol, 2-aminophenol, -amino-4-methylphenol and the like, which may be used alone or in combination of two or more.

As the aniline (C) which is a component of the thermosetting resin, those having the following general formula are used.

However, in the formula, R14 and Rm are hydrogen atoms, alkyl groups, halogen atoms, OC)! 3, OC2H5゜-CO
It is a group such as OCR, -COOC2Hs and does not contain active hydrogen, and its specific compounds include aniline, 0-chloroaniline, 1-toluidine, p-aminobenzoic acid methyl ester, etc. , these may be used alone or in combination of two or more.

As the curing accelerator (d), which is another component of the thermosetting resin, imidazole, imidazole derivatives, 4.4'-
Examples include aromatic amines such as diaminodiphenylsulfone, and specific examples include BF imidazole complex AC-4B series (manufactured by Marukubi Petrochemical Industry Co., Ltd., trade name), which may be used alone or in combination of two or more. and use it.

The thermosetting resin is (a) N,N''-bisimide compound, (
b) Aminophenol, (C) Anilines, (d)
A curing accelerator is an essential component, and the blending ratio thereof will be explained next. N, N'- of unsaturated dicarboxylic acid
The total amount of aminophenol and anilines per mol of bisimide compound [(b)+(C)j is 0.1 to 1.0
It is desirable to mix moles. If the amount is less than 0.1 mol, the softening temperature will be high and the solubility will be poor, and it will not dissolve in low boiling point solvents, which is not desirable. If it exceeds 1.0 mol, the heat resistance and moisture resistance will deteriorate, which is not desirable. The blending ratio of the accelerator is 0.01 to the thermosetting resin.
It is desirable to blend it so that it contains ~5% by weight.
If the blending amount is less than 0.011% by weight, it will not be effective in accelerating curing;
Moreover, if it exceeds 5% by weight, storage stability and workability deteriorate, which is undesirable.The thermosetting resin can be manufactured by blending the above-mentioned components.

The heat-resistant adhesive composition of the present invention has (A) a solvent-soluble chain polyimide resin and (B) a thermosetting resin as essential components, and the proportions thereof are as follows.
The thermosetting resin is blended to contain 95 to 30% by weight of the thermosetting resin to 5 to 70% by weight of the chain polyimide resin. If the amount of the 9-type polyimide resin is less than 5% by weight, film forming properties will be poor, and if it exceeds 70% by weight, the temperature and pressure of adhesion will increase, resulting in poor workability. is produced by blending the above-mentioned components, but the order of blending each component, reaction temperature, solvent, etc. can be selected as appropriate and are not particularly limited.

Typical manufacturing examples of adhesives will be described below.

Charge the N,N'-bisimide compound of unsaturated dicarboxylic acid, aminophenol, and aniline in a predetermined ratio into a reaction container. Raise the temperature of the reaction system to 100 to 200°C to melt the contents while stirring. Proceed with the reaction. As the reaction progresses, the reaction system gradually becomes viscous, so the curing time is measured and the reaction is allowed to proceed to an appropriate point to obtain a thermosetting resin. This resin is dissolved in a solvent such as acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, methyl cellosolve acetate, etc., mixed with a predetermined amount of chain polyimide resin, and a predetermined amount of curing accelerator is added to form a heat-resistant adhesive composition. A resin solution can be obtained. It is also possible to use a solvent from the beginning. For example, a heat-resistant resin is obtained by charging an unsaturated dicarboxylic acid N,N'-bisimide compound, aminophenol, and aniline together with dioxane into a reaction vessel, and proceeding with the reaction while refluxing the dioxane until a predetermined viscosity is exhibited. . Next, a predetermined amount of a chain polyimide resin solution and a predetermined amount of a curing accelerator can be mixed to produce a resin solution of a heat-resistant adhesive composition. The heat-resistant adhesive composition of the present invention is composed of a solvent-soluble chain polyimide resin and a heat-resistant resin, but various additives and additives may be added as necessary to the extent that it does not contradict the purpose of the present invention. Fillers, tackifiers, flame retardants, etc. can be added and blended.

(Function) The heat-resistant adhesive composition of the present invention can obtain the effects of the present invention by including a chain polyimide resin and a thermosetting resin as essential components. In other words, the thermosetting resin consisting of a bisimide compound, aminophenol, aniline, and curing accelerator minimizes hydrophilic hydroxyl groups to improve moisture resistance, and the existing hydroxyl groups act as anti-aging or oxidation prevention. Contributes to heat resistance. In addition, since the curing agent does not decompose unless it reaches a relatively high temperature, it is effective for low-temperature work. On the other hand, chain polyimide resin provides solvent solubility and at the same time I P N (Inter Penetora
tingNetwork) structure and is incorporated into the crosslinked structure of the thermosetting resin, improving heat resistance. This composition can be chemically etched because it becomes a polymer with linked imide rings that polymerize when the double bonds open, so it is very advantageous to use it as an adhesive edge layer for FPC.

(Example) Next, the present invention will be specifically explained with reference to Examples.

Example 1 In a flask equipped with a stirrer and a thermometer, maleic acid N,
N'-4,4'-diphenyl ether bisimide 36
．． 031;1, p-aminophenol 6, OQ, 4.15 g of aniline, and 26 g of dioxane were charged, and the reaction was proceeded while refluxing the dioxane. The reaction was allowed to proceed for 12 hours until the temperature reached 150° C. for 56 seconds using a bubble viscometer to obtain a heat-resistant resin. Add 3 methyl cellosolve acetate to this
0 g was added and cooled to room temperature while stirring. In this solution, 8151 l of a 10% cyclohexanone solution of XT-4293 (our company's chain polyimide resin prototype),
A heat-resistant adhesive composition (adhesive solution) was produced by adding 0.2 g of 2-ethyl-4-methyl-imidazole and 1.2 g of 4,4'-diaminodiphenylsulfone dissolved in 5 g of methyl ethyl ketone. .

This adhesive solution was applied to Kabuton (manufactured by DuPont, trade name), a polyimide film with a thickness of 50 μm, so that the thickness after drying was approximately 25 μm, and then dried at 100°C for 5 minutes and further at 160°C for 2 minutes. did. 3 on this adhesive application surface.
Layering 5μm electrolytic copper foils and using a heat press press,
A substrate for FPC was manufactured by laminating under the conditions of a temperature of 190±2°C, a pressure of 20 kg/crm, and a heating time of 60 minutes.The peel strength of the obtained substrate, adhesion after heat deterioration, and soldering heat resistance , solder resistance after humidification, and line insulation resistance were tested, and the results are shown in Table 1. The remarkable effects of the present invention were confirmed.

Example 2 Malein UN, N'-4,4'-diphenylmethane bisimide 71.66Q, and 0-aminophenol 3.28
g and 1.66 g of p-aminobenzoic acid ethyl ester were heated with occasional stirring to melt the contents. This liquid was stirred vigorously, the temperature was raised to 150°C, the reaction proceeded for about 15 minutes, and then the temperature was lowered to 120"C and the reaction continued for about 30"C.
The reaction was allowed to proceed for a minute to obtain a thermosetting resin. Thereafter, it was poured into an enameled vat, cooled, and pulverized with a mixer. After dissolving the crushed resin 351J in dioxane 35Q, a 15% methyl cellosolve acetate solution 4 of chain polyimide resin XT-4294 (prototype manufactured by our company) was added.
34g and a curing accelerator AC-4850 (manufactured by Maruzen Petrochemical Co., Ltd., trade name of BP, -imidazole complex) 0.3
Prepare 5g of each and stir thoroughly with a high-speed stirrer, 1
A heat-resistant adhesive composition (adhesive solution) was prepared by filtration through a 00 mesh wire mesh. Apply this adhesive solution to a thickness of 25 μm.
Coat m-Kapton (manufactured by DuPont, polyimide film trade name) so that the thickness after drying is approximately 35 μm,
It was dried at 100°C for 5 minutes and then at 150°C for 2 minutes.

For evaluation, a Kapton base copper clad board (copper foil 35 μm) was superimposed on the shine surface of etched silver foil using a hot press at a pressing temperature of 180±2°C.

The lamination was carried out under the conditions of a pressure of 25 ka/cI11" and a heating time of 30 minutes. Using this, the adhesion after heat deterioration, solder heat resistance, solder resistance after humidification, adhesion after soldering, and line insulation resistance were evaluated. The results are shown in Table 1. The remarkable effects of the present invention were confirmed.

Example 3 358 g of maleic acid N, N'-4,4'-diphenylmethane bisimide, 72.31 g of 2-amino-4-chlorophenol, and 27.03 g of 1-toluidine were mixed and heated at 100°C with stirring. When the temperature exceeds 100%, it gradually begins to dissolve and becomes a brown liquid. This liquid was further heated to 120°C and stirred for 1 hour to produce a thermosetting resin.

Dissolve this resin in dioxane to make a 50% solution, and add a 10% dioxane solution of solvent-soluble chain polyimide resin XT-4294-1 (prototype manufactured by our company) to this solution for 10 hours (resin solid content 501; l). 214 g of dimethylbenzylamine and 0.5 g of dimethylbenzylamine were added, thoroughly stirred with a high-speed stirrer, and filtered through a 100-mesh wire mesh to produce a heat-resistant adhesive (adhesive solution). Apply this adhesive solution to a thickness of 35 μm.
It was coated on an electrolytic copper foil so that the thickness after drying would be 25 μm, and dried at 100° C. for 5 minutes and then at 150° C. for 2 minutes. TLB-583-0.8t (manufactured by Toshiba Chemical Co., Ltd., glass-based polyimide resin laminate, trade name) was overlaid with electrolytic copper foil coated with adhesive, and heated using a hot press at a temperature of 200±2°C. A copper-clad laminate was produced by laminating under the conditions of a pressure of 20 kg/cm' and a heating time of 60 minutes.

The resulting laminate was tested for peel strength, adhesiveness after heat deterioration, solder heat resistance, solder resistance after humidification, and line insulation resistance, and the results are shown in Table 1.

The remarkable effects of the present invention were confirmed.

Comparative Example In Example 3, 143.61 g of 2-amino-4-chlorophenol was used instead of 72.31 g of 2-amino-4-chlorophenol and 27.03 g of n-)luidine.
A thermosetting resin and a heat-resistant adhesive composition were produced in the same manner as in Example 3 except that 108.1 g of 1-toluidine was used. In addition, a polyimide resin copper-clad laminate was manufactured in the same manner, and various tests were conducted in the same manner.The results are shown in Table 1.

[Effects of the Invention] As is clear from the above explanation and Table 1, the heat-resistant adhesive composition of the present invention has excellent heat resistance, moisture resistance, and adhesive properties, and also has excellent electrical properties, workability, and storage stability. It is suitable not only as an adhesive for FPC but also as an adhesive for multilayer polyimide.

Claims (1)

[Claims] 1 (A) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, in the formula, R^1 has ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ as the main component, ▲ Mathematical formula, There are chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ R^2 is a tetracarboxylic acid residue containing ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ is the main component, and diamine residues containing ▲ have mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ have mathematical formulas, chemical formulas, tables, etc. ▼ are R^3, R^4, R^5, R^
6 is an alkyl group having 1 to 4 carbon atoms, X is -CH_2-,
-O-, -SO_2-, -C(CH_3)_2-, -C
(CF_3)_2- or -S- divalent group, R^7,
R^8 represents a divalent organic group, R^9 and R^1^0 represent a monovalent organic group, n represents an integer of 2 or more, and p and q represent an integer of 1 or more). 5 to 70% by weight of the solvent-soluble linear polyimide resin shown, and (B) (a) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the formula, R^1^1 represents at least two carbon atoms. N,N'-bisimide compound of unsaturated dicarboxylic acid represented by a divalent group having an atom, R^1^2 represents a divalent group containing a double bond between carbon atoms, and (b ) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, in the formula, R^1^3 represents a hydrogen atom, a halogen atom, or an alkyl group) Aminophenol and (c) General formula ▲ Numerical formula, chemical formula , tables, etc. ▼ (However, in the formula, R^1^4 and R^1^5 represent a hydrogen atom, a halogen atom, or an organic group that does not contain active hydrogen) and (d) curing Thermosetting resin 95 containing an accelerator as an essential component
-30% by weight of a heat-resistant adhesive composition.