JPS646023B2 - - Google Patents

Description

[Detailed description of the invention] [Structure of the invention] (Industrial application field) The present invention uses pure polyimide resin,
This invention relates to a heat-resistant laminate with excellent interlayer adhesion and moisture resistance.

(Prior art) Heat-resistant laminates using pure polyimide resin as the resin are used in electronic equipment, communication equipment, etc., and are particularly required for heat resistance and high reliability in other characteristics. widely used.

As one of the polyimide resins, those obtained by adding aromatic diamine or aniline to bismaleimide are known. These have the disadvantage that they have poor solubility in solvents and are only soluble in nitrogen-containing polar solvents such as dimethylformamide and N-methylpyrrolidone, and the stability of their solutions is also poor. Furthermore, when manufacturing a laminate, the solvent is not completely volatilized and remains, which tends to cause voids, and the molding temperature is somewhat high. On the other hand, aromatic polyimide resins obtained by polycondensation have even worse solubility and molding temperatures of 200°C.
The disadvantage is that the temperature is as high as ℃. Another common problem with laminates using pure polyimide resins is that the adhesive strength with copper foil and the interlayer adhesive strength between glass cloth and glass cloth are weak. In particular, the addition reaction product of bismaleimide and aniline has weak interlayer adhesion. To overcome this drawback, we proposed an addition reaction product of aminophenol and bismaleimide. However, if the amount of aminophenol exceeds a certain level, moisture resistance deteriorates due to the phenolic hydroxyl group, while if the amount falls below a certain level, the reaction time becomes longer.

(Problems to be Solved by the Invention) The present invention was made in order to eliminate the above-mentioned drawbacks, and focuses on improving solubility, low-temperature formability, adhesion with copper foil, interlayer adhesion between glass cloth, and moisture resistance. The purpose of this invention is to provide a heat-resistant laminate with excellent properties.

[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 discovered aminophenol and aniline as amino group-containing compounds to be subjected to an addition reaction with a bisimide compound. It was discovered that by using aminophenol alone, the hygroscopicity due to excessive phenolic hydroxyl groups can be improved, and the adhesive force can be improved by the phenolic hydroxyl groups, and the present invention has been completed. It is something that That is, the present invention provides (A)(a) an N,N'-bisimide compound of an unsaturated dicarboxylic acid represented by the general formula (), (However, in the formula, R ¹ represents a divalent group having at least two carbon atoms, and R ² represents a divalent group containing a double bond between carbon atoms.) (b) General formula ( ) Aminophenol and (However, in the formula, R ³ represents a hydrogen atom, a halogen atom, or an alkyl group) (c) Anilines represented by the general formula () (However, R ⁴ and R ⁵ are hydrogen atoms, alkyl groups,
(a halogen atom, a group such as -OCH ₃ or -OC ₂ H ₅ that does not contain active hydrogen) and (B) a curing accelerator are used. This is a heat-resistant laminate with special characteristics.

(a) is a component of the reaction product (A) used in the present invention
As the N,N'-bisimide compound of unsaturated dicarboxylic acid, one having the following general formula is used.

However, in the formula, R ¹ represents a divalent group having at least two carbon atoms, and R ² represents a divalent group containing a double bond between carbon atoms. That is, R ¹ is a linear or branched alkylene group, 5 carbon atoms
Cycloalkylene groups with ~6 rings, heterocyclic groups containing at least one of oxygen, nitrogen or sulfur atoms, benzene groups or polycyclic aromatics, -NHCO-, -NR ⁶ -, - SiR ⁷ R ⁸ -or-
Examples include multiple benzene groups and alicyclic groups bonded by SO ₂ - or the like. however,
R ⁶ , R ⁷ and R ⁸ each represent an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having a ring having 5 to 6 carbon atoms, a benzene group, or the like. Examples of R ² , that is, a divalent group containing a double bond between carbon atoms, include maleic acid residues, citraconic acid residues, and tetrahydrophthalic acid residues. Therefore, the above
Specific examples of N,N'-bisimide compounds of unsaturated dicarboxylic acids that satisfy the conditions of R ¹ and R ² include the following, and each of these may be used alone or in a mixed system of two or more. be able to. Maleic acid N,N'-4,4'-diphenylmethane bisimide, Maleic acid N,N'-4,4'-diphenyl ether bisimide, Maleic acid N,N'-paraphenylene bisimide, Malein Acid N,N'-benzidine bisimide, maleic acid N,N'-methaxylene bismaleimide, maleic acid N,N'-1.5
-Naphthalene bisimide, maleic acid N,N'-
4,4'-diphenylsulfone-bisimide, maleic acid N,N'-2,2'-4,4'-dimethylene-cyclohexane-bisimide, maleic acid N,
N'-4,4'-dicyclohexane-methane bisimide, maleic acid N,N'-4,4'-diphenylcyclohexane bisimide, maleic acid N,N'-4,
4′-diphenyl-phenylamine-bisimide,
Maleic acid N,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, maleic acid N,N'-metaphenylene-bisimide, maleic acid N,N '-3,
Examples include 3'-(N,N'-metaphenylene-bisbenzamide) bisimide.

As the aminophenol (b) which is another component of the reaction product, one having the following general formula is used.

However, in the formula, R ³ represents a hydrogen atom, a halogen atom, or an alkyl group, respectively. Specific compounds include the following, which may be used alone or in combination of two or more. Examples include o-aminophenol, m-aminophenol, p-aminophenol, 2-amino-4-chlorophenol, 2-amino-4-methylphenol, and the like.

As the aniline (c), which is another component of the reaction product, those having the following general formula are used.

However, in the formula, R ⁴ and R ⁵ are hydrogen atoms, alkyl groups,
Halogen atom, −OCH ₃ , −OC ₂ H ₅ , −COOCH ₃ , −
A group such as COOC ₂ H ₅ that does not contain active hydrogen, specifically aniline, o-chloroaniline,
Any of m-toluidine, methyl-p-aminobenzoic acid ester, etc., which does not contain active hydrogen as a nuclear substituent of aniline, can be used.

Examples of the curing accelerator (B) used in the present invention include imidazole or imidazole derivatives, tertiary amines such as N,N-benzyldimethylamine, and these can be used alone or as a mixture of two or more types. .

Next, when obtaining (A) the reaction product, the blending ratio of (a) N,N'-bisimide compound of unsaturated dicarboxylic acid, (b) aminophenol, and (c) aniline, and (B) curing accelerator. The blending ratio will be explained.

(A) To obtain the reaction product, the sum of (b) aminophenol and (c) anilines [(b)
+(c)] is preferably reacted in an amount of 0.1 to 1.0 mol. If this total blending ratio is less than 0.1 mole,
This is undesirable because the reaction time becomes long and the solubility of the addition reaction product in the solvent deteriorates. Moreover, if the blending ratio exceeds 1.0, the heat resistance of the resin will deteriorate, which is not preferable. Further, the molar ratio [(c)/(b)] of (c) aniline to (b) aminophenol is preferably 0.1 to 9.0. If this molar ratio is less than 0.1, the aminophenol will be in excess, resulting in poor moisture resistance, which is not preferred. In addition, if this molar ratio exceeds 9.0, the solubility of the heat-resistant resin in solvents will deteriorate, and when this resin is used to make a laminate, the adhesive strength with copper foil, glass cloth with glass cloth, carbon fiber with carbon This is because the interlayer adhesion of the fibers deteriorates, which is undesirable.

Next, the blending ratio of the curing accelerator (B) will be explained, and this is blended to improve moldability at low temperatures (200°C or less). The mixing ratio thereof is preferably 0.05 to 2.0% by weight based on the reaction product. If the proportion is less than 0.05% by weight, it will take a long time to perform low-temperature molding by steam heating, and
If it exceeds % by weight, the adjustment temperature range in the prepreg manufacturing process of the laminate becomes narrow, which is not preferable. Therefore,
It is preferably within the above range. In this way, a heat-resistant resin can be obtained by blending the addition reaction product (A) and the curing accelerator (B).

N,N'-bisimide of unsaturated dicarboxylic acid and aminophenol and anilines can be reacted by heating in the melt or in an inert solvent such as dioxane, diglyme, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, etc. You can also do so. In the heating reaction under melting, if N,N'-bisimide of unsaturated dicarboxylic acid, aminophenol and aniline are stirred and the temperature is raised, melting can be achieved at around 100℃, and it is possible to melt at a temperature of 100 to 140℃. If the resin is maintained at a constant temperature, an addition polymerization reaction will occur, and when the desired viscosity is reached, it can be cooled to room temperature to obtain a solid or viscous liquid resin. The obtained resin is dissolved in a solvent such as dioxane, diglyme, methyl cellosolve, etc., and then a predetermined curing accelerator is added to form a uniform heat-resistant resin solution. This is a resin solution for laminates that can be applied to glass cloth, carbon fiber cloth, etc. by impregnating it in a predetermined amount.

In addition, a method of addition polymerization by heating reaction in a solvent uses an inert solvent such as dioxane, diglyme, methyl cellosolve, etc., and at a temperature of 80 to 170°C, N,N'-bisimide of unsaturated dicarboxylic acid and aminophenol are combined. and anilines are heated and stirred,
A resin solution can be obtained by proceeding the reaction until a predetermined viscosity is reached. A predetermined amount of a curing accelerator is added to this resin solution to obtain a uniform heat-resistant resin solution, which is then used as a resin solution for laminated boards that can be impregnated and applied to glass cloth, carbon fiber cloth, etc. in a predetermined amount. Apply the resin solution to glass cloth or carbon fiber cloth and apply it to 80% by the usual method.
Create prepreg by heating and drying with hot air at ~180℃,
Adjust to the desired thickness using a conventional method. A laminate can be obtained by stacking multiple sheets of this prepreg and molding them into a heated and pressurized laminate using steam heating at a maximum temperature of 170 to 190°C, a pressure of 10 to 100 kg/cm ² , and a press time of 1 to 3 hours. .

(Function) The structural formula of the reaction product is presumed to be as follows. Taking bismaleimide as an example, in formula (1), an oligomer is produced in which aminophenol is added to N,N'-bisimide, but the benzene nucleus is bonded to the main chain structure, disrupting the symmetry of the molecule. It is presumed that this and the effect of increased affinity of the phenolic OH group with the solvent improve the solubility of the unsaturated dicarboxylic acid in the solvent, which cannot be achieved with N,N'-bisimide alone.

In addition, at the stage of applying and drying the oligomer produced in equation (1) on glass cloth or carbon fiber cloth, and heating and pressurizing the B-staged prepreg to form a laminate, the reaction as shown in equation (2) and A cross-linking reaction as shown in (3) occurs due to the bonding between the carbon-carbon double bonds of the oligomer, forming a network structure and turning into a thermosetting resin with good heat resistance, resulting in a heat-resistant laminate. If the phenolic hydroxyl group from aminophenol is present in a large amount, it will have a negative effect on moisture resistance, but if it is present in an appropriate amount, it will improve the solubility in the above-mentioned solvents without impairing the moisture resistance, and it will also improve the solubility of copper-clad laminates. In this case, the effect of improving adhesion to copper is large, and the phenolic hydroxyl group is also effective as an antioxidant (antiaging agent).
It is well known that phenolic hydroxyl groups are effective as antioxidants, and hydrogen from phenolic hydroxyl groups is given to peroxide radicals to turn them into stable radicals. This reaction occurs faster than the reaction in which peroxide radicals extract tertiary hydrogen from the polymer (oxidative deterioration reaction), which prevents oxidation.The reason why the resin used in the present invention has good heat resistance is that It is thought that the antioxidant effect of the phenolic hydroxyl group caused by aminophenol also contributes to the heat resistance. Although the phenolic hydroxyl group of aminophenol is effective as described above, it has the disadvantage that moisture resistance deteriorates when present in a large amount. By using anilines in combination, we can suppress the amount of aminophenol blended and reduce the number of phenolic hydroxyl groups, improving moisture resistance, as well as improving adhesive strength, heat resistance, solubility, and low-temperature moldability. It was intended.

EXAMPLES Next, the present invention will be specifically explained by examples.

Example 1 358 g (1 mol) of maleic acid N,N'-4,4'-diphenylmethane bisimide, 32.7 g (0.3 mol) of m-aminophenol, and 64.3 g of m-toluidine
g (0.6 mol) and heated to 100°C with stirring to form a uniformly dissolved brown liquid. This liquid was heated to 130° C. and stirred for 30 minutes, then the reaction product was poured into an enameled pot, cooled, and pulverized with a mixer. 400g of the reactant was dissolved in 215g of dioxane, heated and stirred at a temperature of 110°C for about 4 hours, and when the temperature reached 50°C for 65 seconds using a bubble viscometer, it was cooled, and 218g of methyl cellosolve was added to make a resin with a resin content of 48% by weight. A solution was prepared. 0.5 g of 2-ethyl-4-methylimidazole was added to this solution and stirred well to obtain a uniform mixed solution. Aminosilane-treated glass cloth was impregnated with this solution and air-dried for 30 minutes, then dried in a dryer kept at 110°C for 10 minutes and then at 150°C for 7 minutes to prepare a prepreg. By stacking several sheets of prepreg, the pressure is 40Kg/
cm ² and a temperature of 185° C. for 1 hour under heat and pressure to produce a laminate. After curing this laminate at 200°C for 1 hour, the bending strength was measured at 25°C and found to be 63Kg/mm ² . In addition, the bending strength in an atmosphere of 200℃ is 48Kg/
It can be seen that bending strength is maintained even at high temperatures at mm ² . Insulation resistance (D-2/100+D-0.5/20)
It was 3.0×10 ¹³ Ω. As a reference, a copper-clad laminate was manufactured using a plurality of the prepregs and a 35 μm thick copper foil. This peel strength is 1.90Kg/cm,
The soldering heat resistance at 300°C was 10 minutes or more. It also passed the Measling test (moisture resistance test) even after 6 hours. In all cases, remarkable effects of the present invention were observed.

Example 2 360 g (1 mol) of maleic acid N,N'-4,4'-diphenyl ether bisimide, 32.7 g (0.3 mol) of m-aminophenol, and 27.9 g of aniline.
(0.3 mol) and heated while stirring to 100
When the temperature exceeds ℃, it gradually dissolves and becomes a brown liquid. This liquid was heated to 130° C. and stirred for 30 minutes to react. The reaction product was poured into an enameled pot, cooled, and pulverized with a mixer. 400 g of this reactant was dissolved in 215 g of dioxane at a temperature of approx.
Heat and stir at 110℃ for about 5 hours, and measure 50℃ using a bubble viscometer.
When the temperature reached 61 seconds, the mixture was cooled and 255 g of ethyl cellosolve was added to obtain a resin solution of approximately 46%. 1 g of N,N-benzyldimethylamine was added to this solution and stirred well to obtain a uniform heat-resistant resin solution.

This solution was impregnated and coated on a PAN-based carbon fiber cloth, air-dried for 30 minutes, dried in a dryer kept at 110°C for 10 minutes, and then dried at 150°C for 7 minutes to create a prepreg. Several sheets of this prepreg were stacked and heated and pressed into one piece at a pressure of 50 kg/cm ² and a temperature of 190° C. for 1 hour to obtain a laminate. This laminate
After curing at 200℃ for 15 hours, the bending strength was measured after cooling to 25℃ and it was 125Kg/
mm ² , bending elastic modulus is 5600Kg/mm ² , bending strength in an atmosphere of 200℃ is 105Kg/mm ² , bending elastic modulus is 5490Kg/mm ² , and bending strength retention rate is 84% even at high temperatures. It was hot. In all cases, remarkable effects of the present invention were observed.

Example 3 358 g (1 mol) of maleic acid N,N'-diphenylmethane bisimide and p-aminophenol
27.25g (0.25mol), p-anisidine 6.16g
(0.05 mol) and 211 g of dioxane were placed in a flask, heated and stirred at a temperature of 110 to 115°C for about 40 hours, and the reaction was continued at 50°C for 55 seconds using a bubble viscometer. After cooling, 180 g of methyl cellosolve was added to obtain an approximately 50% resin solution. Add 0.9 g of Kyuazol IB2MZ (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name) as a curing accelerator.
was added and stirred well to obtain a uniform heat-resistant resin solution. This solution was impregnated and coated on an aminosilane-treated glass cloth, air-dried for 30 minutes, then dried in a dryer kept at 110°C for 10 minutes, and then at 150°C for 7 minutes to prepare a prepreg. Several sheets of this prepreg were stacked and heated and pressed into one piece at a pressure of 50 kg/cm ² and a temperature of 180° C. for 1 hour to obtain a laminate. After curing the obtained laminate at 200℃ for 1 hour,
Bending strength was measured after cooling to 25℃.
63Kg/mm ² , bending strength in 205℃ atmosphere 51.7Kg/
mm ² and the retention rate at 205°C was 82%. In addition, the insulation resistance is 10 ¹⁵ Ω or more under normal conditions, and after boiling for 2 hours (D-
2/100) and then cooled with running water at 20℃ for 30 minutes (D-0.5/
20) It was still 8.0×10 ¹³ Ω. In addition, when a copper-clad laminate was manufactured and its peel strength was measured, it was 1.70 kg/cm, and the soldering heat resistance was 300° C. for 10 minutes or more. In all cases, remarkable effects of the present invention were observed.

Comparative Example 1 In Example 1, m-toluidine was replaced with m-toluidine.
A laminate was obtained in the same manner as in Example 1 except that -aminophenol was used, and when a Measling test was conducted, it failed in 2 hours.

[Effects of the Invention] As is clear from the above explanation, the heat-resistant laminate of the present invention can be molded at a low temperature of 200°C or less,
It has excellent adhesive strength with copper foil, interlayer adhesive strength such as between glass cloth, moisture resistance, and heat resistance, and by using it, highly reliable electronic and communication equipment can be obtained. It is extremely advantageous industrially.

Claims (1)

[Scope of Claims] 1 (A)(a) An N,N'-bisimide compound of an unsaturated dicarboxylic acid represented by the general formula (), (However, in the formula, R ¹ represents a divalent group having at least two carbon atoms, and R ² represents a divalent group containing a double bond between carbon atoms.) (b) General formula ( ) Aminophenol and (However, in the formula, R ³ represents a hydrogen atom, a halogen atom, or an alkyl group) (c) Anilines represented by the general formula () (However, R ⁴ and R ⁵ are hydrogen atoms, alkyl groups,
(a halogen atom, a group such as -OCH ₃ or -OC ₂ H ₅ that does not contain active hydrogen) and (B) a curing accelerator are used. A heat-resistant laminate with special features. 2 The reaction product is (a) N of unsaturated dicarboxylic acid,
The sum of (b) aminophenol and (c) aniline [(b) + (c)] for 1 mol of N'-bisimide compound.
The heat-resistant laminate according to claim 1, wherein the heat-resistant laminate is blended in a proportion of 0.1 to 1.0 mole. 3. Heat resistance according to claim 1 or 2, wherein the reaction product has a molar ratio [(c)/(b)] of (b) aminophenol and (c) aniline from 0.1 to 9.0. Laminated board.