JPH0680777A - Soluble polyimide resin - Google Patents

Abstract

PURPOSE:To obtain the title resin excellent in heat resistance and moldability. CONSTITUTION:A polyimide resin soluble in an organic solvent and obtained by reacting an acid component comprising a mixture of a mol of 3,3',4,4'- biphenyltetracarboxylic dianhydride and b mol of 3,3',4,4'- benzophenonetetracarboxylic dianhydride with an amine component comprising a mixture of c mol of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, d mol of 1,3-bis(3-aminophenoxy)benzene and e mol of alpha,omega-bis(3-aminopropyl) polydimethylsiloxane at such a ratio as to satisfy the formulas 0.5<=a/(a+b)<=0.8, 0.2<=b/(a+b)<=0.5 and 0.05<=e/(c+d+e)<=0.5 to thereby effect imide ring closure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin which has excellent heat resistance, low hygroscopicity, is soluble in an organic solvent having a low boiling point, and is excellent in moldability.

[0002]

2. Description of the Related Art Polyimide resins are widely used as electric and electronic materials because of their high heat resistance, flame retardancy and excellent electric insulation. As a film, it is widely used as a base material for flexible printed wiring boards and heat-resistant adhesive tapes, and as a resin varnish for insulating and protective films of semiconductors.
However, conventional polyimide resins have high hygroscopicity and excellent heat resistance, but on the other hand, they are insoluble and infusible or have extremely high melting points, so that they cannot be said to be easy-to-use materials in terms of workability. It is also used as a semiconductor mounting material for interlayer insulating films and surface protective films. These are applied to the semiconductor surface by applying a precursor polyamic acid soluble in an organic solvent and removing the solvent by heat treatment and imidization. We are promoting.
The acid amide-based solvent used at this time has a high boiling point, which may cause foaming of the film or may cause the solvent to completely evaporate.
Since a high temperature drying process of 0 ° C. or higher is required and the device is exposed to a high temperature, the assembly process yield is deteriorated. Further, since the film has a high hygroscopic property, there is a problem that the moisture absorbed at a high temperature evaporates at once and causes blisters and cracks.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The present invention has been earnestly studied to obtain a polyimide resin having excellent heat resistance, low hygroscopicity, and solubility in an organic solvent and excellent moldability.
The present inventors have found that a polyimide resin having a specific structure solves the above problems, and arrived at the present invention.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride a mole and 3,3', 4,4'-
2,2-bis (4- (4-aminophenoxy) phenyl) containing b mol of benzophenone tetracarboxylic dianhydride as an acid component
Amine components of c mole of propane, d mole of 1,3-bis (3-aminophenoxy) benzene and e mole of α, ω-bis (3-aminopropyl) polydimethylsiloxane are used as a, b,
The molar ratio of c, d, and e is 0.5 ≦ a / (a + b) ≦ 0.8,
0.2 ≤ b / (a + b) ≤ 0.5, and 0.05 ≤ e / (c
+ D + e) ≦ 0.5, which is a polyimide resin that is soluble in an organic solvent that has undergone imide ring closure by reacting both components.

The α, ω-bis (3-aminopropyl) polydimethylsiloxane used to obtain the polyimide resin of the present invention is represented by the formula (1).

[0006]

[Chemical 1]

3,3 ', 4,4'-which are the main constituents of the acid component
The molar ratio of biphenyltetracarboxylic dianhydride is extremely important for the solubility of the obtained polyimide resin, and if it is not within the above range, the feature of the present invention that it dissolves in a low boiling point solvent is lost.

The α, ω-bis (3-aminopropyl) polydimethylsiloxane represented by the formula (1) preferably has n = 0 to 10 and, particularly, when the value of n is 4 to 10, the glass transition temperature is It is preferable in terms of adhesiveness and heat resistance. In addition, blending n = 0 and the above n = 4 to 10 is preferable especially for applications where importance is placed on adhesiveness.

Other acid anhydrides and diamines used in the production of polyimide, such as 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane (BAPP)
F), 2,2-bis (4-aminophenoxy) hexafluoropropane (BAPF), bis-4- (4-aminophenoxy) phenyl sulfone (BAPS), bis-4- (3-aminophenoxy) phenyl sulfone ( It is possible to add BAPSM) in a small amount within a range that does not impair the characteristics.

It is important that the amount ratio of each component is within the above range, and if the content of α, ω-bis (3-aminopropyl) polydimethylsiloxane is less than 5 mol% of all amine components, low hygroscopicity is characteristic. If it does not appear and exceeds 50 mol%, the glass transition temperature is remarkably lowered and a problem occurs in heat resistance. The molar ratio of 2,2-bis (4- (4-aminophenoxy) phenyl) propane is preferably in the range of 0.1 ≤ c / (c + d + e) ≤ 0.9. There is a problem with sex.

The equivalent ratio of the acid component and the amine component in the polycondensation reaction is an important factor that determines the molecular weight of the polyamic acid obtained. It is well known that there is a correlation between polymer molecular weight and physical properties, especially number average molecular weight and mechanical properties. The larger the number average molecular weight, the better the mechanical properties. Therefore, in order to obtain practically excellent strength, it is necessary that the polymer has a high molecular weight to some extent. In the present invention,
The equivalent ratio r of the acid component and the amine component is 0.900 ≤ r ≤ 1.06, more preferably 0.975 ≤
It is preferable that r is within the range of 1.06. However, r = [equivalent number of all acid components] / [equivalent number of all amine components]. r is 0.
If it is less than 900, the molecular weight is low and it becomes brittle, so the adhesive strength becomes weak. On the other hand, if it exceeds 1.06, unreacted carboxylic acid may be decarboxylated during heating to cause gas generation and foaming, which is not preferable. On the other hand, if the value is exactly 1.00, the molecular weight becomes too high depending on the reaction conditions, which may not be preferable.

The reaction between the tetracarboxylic dianhydride and the diamine is carried out by a known method in an aprotic polar solvent. The aprotic polar solvent is N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA
C), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), diglyme, cyclohexanone,
1,4-dioxane and the like. The aprotic polar solvent is
Only one kind may be used, or two or more kinds may be mixed and used. At this time, a non-polar solvent compatible with the aprotic polar solvent may be mixed and used. Aromatic hydrocarbons such as toluene, xylene and solvent naphtha are often used. The proportion of the non-polar solvent in the mixed solvent is preferably 30% by weight or less. This is because if the amount of the nonpolar solvent is 30% by weight or more, the solubility of the solvent may decrease and polyamic acid may precipitate. The reaction between the tetracarboxylic dianhydride and the diamine is carried out by dissolving a well-dried diamine component in the above-mentioned reaction solvent which has been dehydrated and purified, and then the ring closure rate is 98%, more preferably 99% or more of the well-distilled tetracarboxylic acid dianhydride. Anhydrous is added to drive the reaction.

The polyamic acid solution thus obtained is subsequently heated and dehydrated in an organic solvent to form an imidized polyimide. Since the water generated by the imidization reaction interferes with the ring-closing reaction, an organic solvent that is incompatible with water is added to the system to azeotropically evaporate it and use a device such as a Dean-Stark tube to remove it from the system. To discharge. Dichlorobenzene is known as an organic solvent which is incompatible with water, but for electronics use, the aromatic hydrocarbon is preferably used since chlorine components may be mixed therein. Further, the use of compounds such as acetic anhydride, β-picoline and pyridine as a catalyst for the imidization reaction is not hindered.

In the present invention, the higher the degree of imide ring closure, the better. When the imidization ratio is low, imidization occurs due to heat during use and water is generated, which is not preferable. Therefore, 95% or more, more preferably 98% or more. It is desirable that the imidization ratio of is achieved.

In the present invention, the obtained polyimide solution can be used as it is as a coating varnish. Also,
The polyimide solution may be poured into a poor solvent to reprecipitate and precipitate the polyimide resin to remove unreacted monomers, purified, and dried to be used as a solid polyimide resin. In applications where high-temperature processes are disliked or where impurities and foreign substances are particularly problematic, it is preferable to dissolve them again in an organic solvent to obtain a filtration / purification varnish. The solvent used at this time can be selected from those having a low boiling point in consideration of workability.

In the polyimide resin of the present invention, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone are used as ketone solvents, and 1,4-dioxane, tetrahydrofuran and diglyme are used as ether solvents having a boiling point of 200 ° C. or less. It can be used as a low boiling point solvent. These solvents may be used alone or in combination of two or more.

The method of using the polyimide resin of the present invention is not particularly limited, but it is dissolved in an organic solvent to form a resin varnish for coating or dipping, cast for forming a film, and solid state for extrusion molding. It can be used as an insulating material, an adhesive film, or the like having both heat resistance and processability.

[0018]

The polyimide resin of the present invention is a polyimide resin having a specific structure which is soluble in an organic solvent even after being completely imidized, and although it has excellent heat resistance, it is thermosetting with a chemical reaction. Molding is possible in a shorter time than resin. The present invention is described in detail below with reference to examples, but the present invention is not limited to these examples.

[0019]

【Example】

(Example 1) NMP750 dehydrated and refined in a four-necked flask equipped with a dry nitrogen gas introduction tube, a condenser, a thermometer, and a stirrer.
Add g and stir vigorously for 10 minutes while flowing nitrogen gas. Next, 2,2-bis (4- (4-aminophenoxy) phenyl) propane (BAPP) 82.1029 g (0.200 mol), 1,3-bis
(3-Aminophenoxy) benzene (APB) 8.0092 g (0.
027 mol) and α, ω-bis (3-aminopropyl) polydimethylsiloxane (APPS) 34.3973 g (average molecular weight 840.3
6, 0.041 mol), α, ω-bis (3-aminopropyl) tetramethyldimethylsiloxane (APPS, n = 0) 1.3617 g
(0.005 mol, n = 0 in formula (1)) was added and the system was
Heat to 60 ° C and stir until uniform. After being uniformly dissolved, the system was cooled to 5 ° C. in an ice-water bath, and 40.3041 g (0.137 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride,
3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride 4
4.1411 g (0.137 mol) was added in powder form over 15 minutes and stirring was continued for 3 hours thereafter. During this time the flask is 5
It was kept at ℃.

After that, the nitrogen gas introducing pipe and the cooler were removed,
A Dean-Stark tube filled with xylene was attached to the flask, and 187 g of toluene was added to the system. Instead of the oil bath, the system was heated to 175 ° C. and the water generated was removed from the system. After heating for 4 hours, generation of water from the system was not observed. After cooling, this reaction solution was poured into a large amount of methanol to precipitate a polyimide resin. After filtering solids at 80 ° C
192.43 g (yield 91.5%) after removing the solvent by drying under reduced pressure for 12 hours
Of solid resin was obtained. When the infrared absorption spectrum was measured by the KBr tablet method, it was found to be 5.6 μm derived from the cyclic imide bond.
However, the absorption of 6.06 μm derived from the amide bond was not recognized, and it was confirmed that this resin was almost 100% imidized.

It was confirmed that the polyimide resin thus obtained was well soluble in cyclohexanone / toluene (90/10 w / w%). At this time, the molar ratios of acid and amine are a / (a + b) = 0.5 and b / (a + b), respectively.
= 0.5 and e / (c + d + e) = 0.17.

(Examples 2 to 4) In the same manner as in Example 1,
Soluble polyimide resin was obtained by reacting with the formulation shown in Table 1. The evaluation results obtained for these polyimide resins are shown in Table 1. It can be seen that all have excellent solubility in organic solvents.

[0023]

[Table 1]

In Table 1, BPDA is 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and BTDA is 4,4'.
-Benzophenone tetracarboxylic dianhydride, BAP
P is 2,2-bis (4- (4-aminophenoxy) phenyl) propane, APB is 1,3-bis (3-aminophenoxy) benzene, and APPS is α, ω-bis (3-aminopropyl). Each of them is an abbreviation for polydimethylsiloxane.

The numerical value of the compound is the compound equivalent ratio in each component, and the water absorption rate is 500 at 85 ° C. and 85% RH.
Saturated water absorption after leaving for a while (HH-500 treatment)
The generated water is a value obtained by quantifying the gas generated by heating at 250 ° C. for 15 minutes by the GC-MS method, and the water content by the Karl Fischer method. S in the solubility column indicates that the compound is soluble in the corresponding solvent.

(Comparative Example 1) Under the same conditions as in Example 1, BPD
A, BTDA and BAPP are a / (a + b) = 0.5, b /
(A + b) = 0.5, c / (c + d + e) = 1 (d = 0,
e = 0) and reacted to obtain a polyimide resin. An attempt was made to dissolve this resin in cyclohexanone, but it was in a swollen gel state and could not be completely dissolved. Also,
The same condition was obtained for DMF and DMAC, and the resin varnish could not be prepared.

(Comparative Examples 2 to 4) As in Example 1, the second
Table 2 shows the results of evaluation of the polyimide resin obtained by reacting with the formulation shown in the table.

[0028]

[Table 2]

In Table 2, PMDA is 1,2,4,5-
Benzenetetracarboxylic dianhydride, 4,4'-DDE
Abbreviation of 4,4′-diaminodiphenyl ether, I in the solubility column indicates insolubility in the corresponding solvent.
The above examples show that the present invention makes it possible to obtain a polyimide resin which is soluble in an organic solvent and has excellent heat resistance and low hygroscopicity.

[0030]

According to the present invention, it is possible to provide a polyimide resin having excellent heat resistance and moldability. Since it is soluble in a low boiling point solvent, it is possible to almost completely eliminate the residual solvent, and since it has already been imidized, a high temperature process is unnecessary and no water is generated. Therefore, it is industrially extremely useful as a material for electronics that requires high reliability and heat resistance.

Claims (1)

[Claims] 1. An acid component comprising 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride a mole and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride b mole, 2,2-bis (4- (4-
Aminophenoxy) phenyl) propane (cmol), 1,3-bis (3-aminophenoxy) benzene (dmol), α, ω-bis
(3-Aminopropyl) polydimethylsiloxane as an amine component with a mole ratio of a, b, c, d, and e of 0.5
≤ a / (a + b) ≤ 0.8, 0.2 ≤ b / (a + b) ≤
A polyimide resin soluble in an organic solvent, which is obtained by reacting both components at a ratio of 0.5 and 0.05 ≦ e / (c + d + e) ≦ 0.5 to imide ring closure.