JPH04325560A - Granular aromatic polyimide resin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. exhibiting improved handleability during molding and giving a molding having high strengths. CONSTITUTION:The title compsn. is prepd. by compounding an arom. polyimide resin with an aliph. amide compd. of the formula wherein R<1> and R<3> are each a 4-20C monovalent aliph. group; R<2> is a 1-20C divalent aliph. group; X is an amide group; and n is an integer of 0-10 and has a mean granule size of 30-1000mum.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a granular aromatic polyimide resin composition with improved moldability.

0002

[Prior Art] Aromatic polyimide resins have an important role in the electric/electronic equipment industry, the automobile industry, etc. due to their excellent heat resistance and mechanical properties. As performance advances, it is becoming an indispensable material. Since these aromatic polyimide resins have extremely high heat resistance, it is difficult to apply the injection molding method used for molding ordinary resins, and they are generally molded by a sintering molding method. In order to perform sintering and molding, the raw material powder must be extremely fine powder.
No. 22196 and Japanese Patent Publication No. 39-30060 disclose methods for producing such finely powdered polyimide.

[0003] Furthermore, Japanese Patent Publication No. 58-35459 and Japanese Patent Publication No. 62-23642 disclose a method for obtaining granular polyimide by compressing powdered polyimide into a lump and then pulverizing it. There is.

0004

[Problems to be Solved by the Invention] However, when actually molding polyimide in the form of fine powder, (1) the bulk density is small, so a mold that is considerably larger than the dimensions of the final molded product is required; (2) Since it lacks fluidity as a powder, it cannot be fed smoothly to the mold, and automatic feeding is particularly difficult, so improvements are desired.

[0005] Furthermore, according to the methods disclosed in Japanese Patent Publication No. 58-35459 and Japanese Patent Publication No. 62-23642, polyimide which is granular and has improved handling properties can be obtained, but these methods The granules obtained in this method have a problem in that they have poor cohesiveness during sintering and forming, leaving grain boundaries, resulting in molded products with low mechanical strength.

The object of the present invention is therefore to solve these drawbacks of conventional polyimides and to obtain a granular aromatic polyimide resin composition that has improved handling properties during molding and has high strength after molding.

[0007]

[Means for Solving the Problems] That is, the present invention provides aromatic polyimide resin of 99.9 to 80% by weight and formula (I).

[
0008

[Chemical formula 3]

(In the formula, R1 and R3 have 4 to 20 carbon atoms.
R2 is a divalent aliphatic residue having 1 to 20 carbon atoms, X is an amide group, and n is an integer of 0 to 10). ~20% by weight
and has an average particle size of 30
For the granular aromatic polyimide resin composition and the above granular aromatic polyimide resin composition having a particle size of 1,000 μm, the formula (I)

0010

[C4]

[0011] (In the formula, R1 and R3 have 4 to 20 carbon atoms.
R2 is a divalent aliphatic residue having 1 to 20 carbon atoms, X is an amide group, and n is an integer of 0 to 10). The present invention is a granular aromatic polyimide resin composition in which the proportion of an aliphatic amide compound in the entire composition is 20.5% by weight or less.

[0012] The method for producing the aromatic polyimide resin used in the present invention is known, and the details are disclosed, for example, in 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 and their diisocyanates.

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

[0015]

[C5]

[0016] This includes products in which the imide group remains in the form of amic acid, which is its ring-closing precursor, but in order to prevent gas generation during molding, 80% or more must be imidized. is preferred.

The aliphatic amide compound used in the present invention has the formula (I)

[0018]

[C6]

It is a compound represented by the following formula, where R1
, R3 is a monovalent aliphatic residue having 4 to 20 carbon atoms, specifically, butyl group, hexyl group, cyclohexyl group,
Examples include isopentyl group, heptadecyl group, and 8-heptadecenyl group. Also, R2 is 2 having 1 to 20 carbon atoms.
Specific examples include a methylene group, an ethylene group, a propylene group, a hexylene group, a 1,4-cyclohexylene group, and a decylene group. Further, X is an amide group, n is an integer of 0 to 10, and 0
-4 is preferred. When n is 1 or more, two or more Xs exist in one molecule, and in that case, the orientation of the amide group for each X is -CONH- or -NHCO
- It doesn't matter.

Particularly preferred aliphatic amide compounds are (
These are mono- or diamide compounds represented by II) to (IV), and a typical example is palmitic acid-
n-hexylamide, ethylene bisstearylamide,
Examples include methylenebislaurylamide, oleic acid-n-octylamide, and adipate bis(n-octyl)amide.

R1-CONH-R3
(II) R1 -CONH-R2 -NHC
O-R3 (III) R1 -NHCO-R2 -CO
NH-R3 (IV) The role of this aliphatic amide compound is to act as a binder to maintain the granule shape during granulation.

In general, in the field of ceramics, many binders for use in granulation have been studied, and several binders have been proposed. Common binders include polyvinyl alcohol, methyl cellulose, polyethylene glycol, and low molecular weight polyethylene.

[0023] Even if these binders used in the ceramic field are applied as they are, the mechanical strength after molding decreases, and it is extremely difficult to obtain a product of practical use. As a result of a detailed study on what is suitable as a binder when granulating polyimide, the present inventor found that aliphatic amide has a high binding ability as a binder and does not reduce the mechanical strength of the final molded product. They discovered that the compound is excellent, and arrived at the present invention.

[0024] Here, it is extremely important not to reduce the mechanical strength of the final molded product. This is because in the case of ceramics, heat of about 1000°C is applied during the degreasing process, so the organic matter in the binder can be completely removed. On the other hand, in the case of polyimide, no matter how high its heat resistance is, the molding temperature is at most 500°C, and since polyimide itself is an organic polymer, some of the polyimide decomposes during the process of removing the binder by thermal decomposition. Otherwise, the binder may not be completely removed, resulting in a loss of strength.

However, the granules using an aliphatic amide compound as a binder as disclosed in the present invention not only have improved handling properties but also have no adverse effect on the final molded product and can be molded with high strength. It is possible to give goods.

In the composition of the present invention, the proportion of the aliphatic amide compound is preferably 0.1 to 20% by weight, preferably 0.
．． 3 to 10% by weight is good. If it is less than 0.1% by weight, the effect as a binder is poor and granules cannot be obtained, which is undesirable. If it exceeds 20% by weight, a large amount of decomposed gas is generated during molding, making the molded product more likely to crack. .

[0027] Furthermore, the average particle size of the granules is 30 to 1000
The thickness is preferably 50 to 500 μm. If it is less than 30 μm, it is difficult to handle and is not preferred, and if it is 1000 μm
Exceeding this is not preferable because grain boundaries remain after molding and the strength decreases.

In the present invention, in order to obtain a granular composition, the spray drying method, rolling granulation method, fluidized bed granulation method, etc., which are usually used for granulating ceramics, are used. Among these, the spray drying method is preferred.

In the present invention, by further blending the obtained granules with an aliphatic amide compound represented by the formula (I), it is possible to impart further slipperiness, thereby improving the handling properties of the granules. Further improvements can be made. The blending amount of the aliphatic amide compound in the obtained granules is such that the aliphatic amide compound in the entire composition is
There is no particular restriction as long as it is 20.5% by weight or less, but it is preferably used in a range of 0.5% by weight or less, particularly preferably 0.1% by weight or less, based on the obtained granules. The proportion of aliphatic amide compound in the total composition is usually 20
．． It is preferably 5% by weight or less, preferably 20% by weight or less, and particularly preferably 0.3 to 10.5% by weight.

[0030] There are no particular restrictions on the method of blending the aliphatic amide compound into the obtained granules, but dry blending can usually be used.

[0031]Furthermore, fillers may be added to the composition of the present invention as needed to improve various properties such as heat resistance, mechanical properties,
Examples of such fillers include graphite,
Fluororesin, molybdenum disulfide, boron nitride, mica,
Examples include talc, glass fiber, carbon fiber, aramid fiber, potassium titanate fiber, aluminum, silver, copper, lead, and various metal oxides.

[0032]

[Examples] The present invention will be explained in more detail with reference to Examples below. The molding in the examples was carried out 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 for 50
The temperature was raised from .degree. C. to 450.degree. C. over 5 hours, and then heat-treated at 450.degree. C. for 1 hour. 65m from the molded product thus obtained
A test piece measuring m x 13 mm x 3 mm was cut out and subjected to a bending test.

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 and 2 and Comparative Examples 1 to 3 PI-A
and ethylene bis stearylamide [CH3 (CH
2) 16CONH-CH2 CH2-NHCO(C
H2)16CH3] toluene/acetone=1/1(
Weight ratio) After dispersing in a mixed solvent to a solid concentration of 10% by weight, it was placed in a spray dryer and heated to a temperature of 8%.
Spray drying was carried out under the conditions of 0° C., air flow rate of 4 m/min, and liquid feed rate of 60 ml/min. The average particle diameter and bulk density of the granules obtained in Examples 1 and 2 are as shown in Table 1, and the handleability was improved compared to the bulk powder (Comparative Example 1). Furthermore, the mechanical strength after molding was also good.

On the other hand, in Comparative Example 2, which did not use an aliphatic amide compound, no granules were obtained and it was difficult to handle like the bulk powder.

Furthermore, as shown in Comparative Example 3, if the amount of the aliphatic amide compound added is too large, cracks will occur during molding, which is undesirable.

[0039]

[Table 1]

Comparative Examples 4 to 7 In Example 1, polyvinyl alcohol (abbreviated as PVA), methyl cellulose (abbreviated as MC), polyethylene glycol 600 (abbreviated as PEG) were used instead of the aliphatic amide compound.
), and low molecular weight polyethylene (abbreviated as PE),
A similar experiment was conducted using the solvents shown in Table 2. The results are shown in Table 2, and it was found that the strength of each sample was significantly reduced and that they were unsuitable as a binder.

[0041]

[Table 2]

Comparative Example 8 PI-A was put in a mold and heated at 500 kgf/cm2 at room temperature.
After applying pressure to form a green compact, it was crushed to obtain granules (
average particle size 300 μm). Subsequently, this granule was molded and evaluated in the same manner as in Example 1, but grain boundaries remained on the surface of the molded product, and the bending strength was as low as 400 kgf/cm2.

Example 3 and Comparative Example 9 PI-B and methylenebislaurylamide [CH3
(CH2)10CONHCH2 NHCO(CH2
)10CH3 ], an experiment similar to that in Example 1 was conducted. The results are shown in Table 3, and the one containing the aliphatic amide compound had a granular shape that was easy to handle and maintained its strength. On the other hand, in a comparative example in which no aliphatic amide compound was used, no granules were obtained and the handling properties were poor.

[0044]

[Table 3]

Example 4 and Comparative Example 10 PI-C and adipic acid bis(n-octyl)amide [CH3 (C
H2 )7 NHCO(CH2 )4 CONH(CH
2) An experiment similar to Example 1 was conducted using 7CH3]. The results are shown in Table 4, and the one containing the aliphatic amide compound had a granular shape that was easy to handle, and the strength was maintained. On the other hand, in a comparative example in which no aliphatic amide compound was used, granules were not obtained and the handling properties were poor.

[0046]

[Table 4]

Example 5 To 100 parts by weight of the granules obtained in Example 1, 0.1 part by weight of ethylene bisstearylamide was dry blended. These granules had superior lubricity compared to the granules of Example 1, were more smoothly fed into the mold, and had further improved handling properties.

[0048]

Effects of the Invention As is clear from the Examples and Comparative Examples, the granular composition of the present invention has significantly improved handling properties during molding, and the strength of the molded product is maintained. Therefore, products with high strength can be manufactured in a highly productive manner.

The polyimide molded product thus obtained has excellent heat resistance, mechanical properties, sliding properties, etc., and is useful for electrical/electronic parts, automobile parts, office equipment parts, space/aircraft parts, etc. be.

Claims (2)

[Claims] [Claim 1] Aromatic polyimide resin 99.9-80
Weight % and Formula (I) [Formula 1] (wherein, R1 and R3 are monovalent aliphatic residues having 4 to 20 carbon atoms, R2 is a divalent aliphatic residue having 1 to 20 carbon atoms,
X is an amide group, n is an integer of 0 to 10);
A granular aromatic polyimide resin composition which is m. [Claim 2] The granular aromatic polyimide resin composition according to Claim 1 further comprises a compound of the formula (I) [Chemical formula 2] (wherein R1 and R3 are monovalent aliphatic residues having 4 to 20 carbon atoms). group, R2 is a divalent aliphatic residue having 1 to 20 carbon atoms,
A granular aromatic polyimide resin composition containing an aliphatic amide compound represented by A granular aromatic polyimide resin composition having a proportion of 20.5% by weight or less.