JPH04359053A - Polyimide resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyimide resin composition, improved in rigidity while holding toughness and suitable as mechanical parts by blending an aromatic polyimide resin with a specific amount of gypsum. CONSTITUTION:A polyimide resin is obtained by dry blending (A) 99-30wt.%, especially 95-60wt.% aromatic polyimide resin, preferably prepared from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether and having a structure expressed by the formula with (B) preferably 1-70wt.%, especially 5-40wt.% gypsum consisting essentially of calcium sulfate having 0.1-100mum, especially 1-20mum average particle size, preferably semihydrate gypsum (CaSO4.1/2H2O) and anhydrous gypsum (CaSO4) using a Henschel mixer, etc., or adding and mixing a prescribed amount of the component (B) in polymerizing the component (A). The aforementioned polyimide resin composition is excellent in rigidity and toughness.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin composition having excellent rigidity and toughness.

0002

[Prior art] Polyimide resin has excellent heat resistance,
Due to its mechanical properties, sliding properties, etc., demand for it has increased rapidly in recent years in the electrical/electronic equipment industry, the automobile industry, the aerospace industry, the office equipment industry, etc. However, when used as mechanical parts, the rigidity of polyimide resins is not necessarily sufficient, and improvements are desired.

Addition of various reinforcing materials and fillers is an effective method for improving rigidity.
Publication No. 37 discloses mica, kaolin, and asbestos; Japanese Patent Publication No. 58-35459 discloses talc, silica, and glass powder; Japanese Patent Publication No. 61-281150 discloses polyimide containing carbon fiber, boron nitride, and alumina. A resin composition is disclosed.

0004

[Problem to be solved by the invention] However,
Polyimide resin compositions containing fillers such as those disclosed in Japanese Patent Publication No. 737, Japanese Patent Publication No. 58-35459, and Japanese Patent Application Laid-Open No. 61-281150 have improved rigidity, but on the other hand, toughness (especially tensile strength) is improved. There is a problem in that the elongation at break) decreases significantly.

[0005] Therefore, the object of the present invention is to obtain a polyimide resin composition with improved rigidity and less decrease in toughness.

[0006]

[Means for Solving the Problems] That is, the present invention comprises 99 to 30% by weight of aromatic polyimide resin and 1 to 70% by weight of gypsum.
It is a polyimide resin composition formed by blending % by weight.

In the present invention, it is important to blend a specific amount of gypsum into the aromatic polyimide resin, thereby providing a composition with improved rigidity and less decrease in toughness.

[0008] The method for producing the aromatic polyimide resin used in the present invention is known, and the details are disclosed in, for example, Japanese Patent Publication No. 39-22196. It can be produced by reacting an aromatic diisocyanate in an organic polar solvent (for example, N-methylpyrrolidone, N,N-dimethylacetamide, diglyme, etc.) and subjecting the resulting polyamic acid to dehydrated imide ring closure. Specific examples of the aromatic tetracarboxylic dianhydride used here include pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4 '-Biphenyltetracarboxylic dianhydride, 2,3,3',4
'-Biphenyltetracarboxylic dianhydride, 2,2',
3,3'-biphenyltetracarboxylic dianhydride, 3,
3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane 2-anhydride, 2,2-bis(
3,4-Dicarboxyphenyl)hexafluoropropane dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4 , 5,8-naphthalenetetracarboxylic dianhydride, and the like. Further, these acid dianhydrides can also be used in the form of their derivatives such as carboxylic acids, esters, and acid chlorides.

Specific examples of aromatic diamines and aromatic diisocyanates include p-phenylenediamine, m-
phenylenediamine, 2-chloro-p-phenylenediamine, benzidine, 2-chlorobenzidine, 4,4'-
Diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-
Diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl ketone, 3,3'-diaminodiphenyl ketone, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminoterphenyl, 1 , 4-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1
, 3-bis(3-aminophenoxy)benzene, bis[
4-(4-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]ketone,
2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-bis(4-aminophenoxy) Examples include biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, and diisocyanates thereof.

Among them, preferred aromatic polyimide resins are:
This is a polyimide having the following structure obtained from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether.

[0011]

[Chemical formula 1]

[0012] Here, it also includes those in which the imide group remains in the form of an amic acid, which is its ring-closed precursor.

[0013] The gypsum used in the present invention has calcium sulfate as its main component, and is composed of dihydrate gypsum (CaSO4.2
H2 O), gypsum hemihydrate (CaSO4 ・1/2 H2
There are three types: O) and anhydrite (CaSO4). Any of these may be used, but gypsum hemihydrate and gypsum anhydrite are particularly preferred. Also, both natural products and artificial products (chemical gypsum) can be used.

[0014] It is preferable to use powdered gypsum having an average particle size of 0.1 to 100 μm, preferably 1 to 50 μm, particularly preferably 1 to 20 μm.

The proportion of the aromatic polyimide resin in the polyimide resin composition of the present invention is preferably 99 to 30% by weight, preferably 97 to 50% by weight, particularly preferably 95 to 60% by weight. The blending ratio of gypsum is 1 to 70% by weight, preferably 3 to 50% by weight, particularly preferably 5 to 40% by weight. If the blending ratio of gypsum is less than 1% by weight, there is no effect of improving rigidity, and if it exceeds 70% by weight, the toughness will be significantly lowered, which is not preferable.

[0016] Further, other fillers can be added to the composition of the present invention as needed to impart desired properties. Examples of such fillers include graphite, fluororesin, Examples include molybdenum sulfide, boron nitride, glass fiber, carbon fiber, aramid fiber, potassium titanate fiber, aluminum, silver, copper, lead, and various metal oxides. Methods for preparing the composition of the present invention include a method of dry blending using a Henschel mixer, or a method of wet blending in an appropriate solvent. There is no problem.

[0017]

[Examples] The present invention will be explained in more detail with reference to Examples below. In addition, the molding in the examples was performed as follows. That is, a mold is filled with resin and a pressure of 3000 kgf/cm2 is applied at room temperature to form a green compact. Next, this green compact was placed in a nitrogen-substituted oven, and
Raise the temperature from 0℃ to 450℃ in 5 hours, then further increase to 450℃
It was heat-treated for 1 hour. From the molded product thus obtained, 65
A test piece of mm x 13 mm x 3 mm was cut out and subjected to tensile and bending tests.

Production Example 1 Production of Polyimide-A 4,4
'-Diaminodiphenyl ether (DDE) 60.07
g (0.3 mol) was dissolved in 1200 g of N,N-dimethylacetamide (DMAc), and 65.44 g (0.3 mol) of pyromellitic dianhydride (PMDA) was gradually added thereto. After the addition was completed, stirring was continued for another hour, and ηinh (in DMAc, concentration 0.5 g/dl,
A polyamic acid solution having a temperature (measured at 30° C.) of 2.00 was obtained. Next, the temperature of this was adjusted to 30° C., and 3000 g of acetone was added to form a homogeneous solution. While stirring vigorously, 200 g of acetic anhydride and 200 g of pyridine were added.
A yellow polyimide powder was precipitated, which was filtered.
After washing with acetone, it was dried in vacuo at 160° C. for 15 hours to obtain polyimide-A powder (hereinafter referred to as PI-A).

Production Example 2 Production of Polyimide-B In Production Example 1, PMDA43 was used as the tetracarboxylic acid component.
．． Polyimide-B powder (hereinafter referred to as PI- (referred to as B) was obtained.

Production Example 3 Production of Polyimide-C In Production Example 1, 16.22 g (0.15 mol) of paraphenylenediamine and bis[4-
(4-aminophenoxy)phenyl]sulfone 64.8
7 g (0.15 mol) of the mixture was used, and 88.27 g (0.3 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride was used as the tetracarboxylic acid component. Polymerization was carried out in a similar manner to obtain polyimide-C powder (hereinafter referred to as PI-C).

Examples 1 to 3 and Comparative Examples 1 to 6 Gypsum hemihydrate (α Gypsum "TA-20") manufactured by Toray Industries, Inc. was ground in a hammer mill to obtain a fine powder of gypsum hemihydrate. The average particle size of this product was 8 μm. Next, this gypsum powder and PI-A were dry blended with the composition shown in Table 1, and then compression molded and subjected to tensile and bending tests. The results are shown in Table 1, and the compositions of Examples 1 to 3 containing gypsum have improved elastic modulus (rigidity) compared to the blank (Comparative Example 1). In addition, it is noteworthy that the decrease in toughness (tensile elongation) is small, and in particular, the product containing 20% by weight of gypsum (Example 1) maintains the same level of tensile elongation as the blank.

On the other hand, compositions containing other fillers such as those in Comparative Examples 3 to 6 improve the elastic modulus, but the toughness (
The decrease in tensile elongation is significant. Furthermore, when the amount of gypsum blended is extremely large as in Comparative Example 2, the strength and elongation decrease significantly, which is undesirable.

[0023]

[Table 1]

Examples 4 to 7 and Comparative Examples 7 to 10 The hemihydrate gypsum powder used in Example 1 was heat treated at 350°C for 5 hours.
It was made of anhydrite. This was dry blended with PI-B and PI-C in the composition shown in Table 2, then compression molded and subjected to tensile and bending tests. The results are shown in Table 2, and the compositions containing gypsum have improved elastic modulus and less decrease in elongation. On the other hand, compositions containing other fillers are undesirable because of a significant decrease in elongation.

[0025]

[Table 2]

[0026]

Effects of the Invention As is clear from the Examples and Comparative Examples, the compositions of the present invention have improved rigidity while maintaining toughness. Therefore, it is suitable for use as a mechanical part, and is useful in the electrical/electronic industry, the automobile industry, the aerospace industry, etc.

Claims (1)

[Claims] 1. A polyimide resin composition comprising 99 to 30% by weight of an aromatic polyimide resin and 1 to 70% by weight of gypsum.