JPS62132960A - Polyimide resin formed body - Google Patents

Abstract

PURPOSE:To obtain the titled formed body outstanding in mechanical strength, frictional and wearing characteristics, etc., suitable for functional parts (under such severe conditions as elevated temp. eratures, by heating and compression molding of a polyimide resin composition prepared by incorporating an aromatic polyimide resin with each specified amount of each specific inorganic fibrous filler and solid lubricant. CONSTITUTION:The objective formed body can be obtained by blending (A) 35-85 (pref. 40-80)wt% of aromatic polyimide resin powder with an average granular size 1-40mum, (B) 10-40 (pref. 15-40)wt% of inorganic fibrous filler with an average fiber diameter 0.1-15mum and aspect ratio 10-100 (e.g. glass fiber, carbon fiber) and (c) 5-25 (pref. 5-20)wt% of solid lubricant with an average granular size 1-30mum (e.g. fluororesin powder, molybdenum disulfide), followed by heating and compression molding.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a polyimide resin molded article, more specifically, an aromatic polyimide resin powder containing specific amounts of a specific inorganic fibrous filler and a specific solid lubricant. The present invention relates to a polyimide resin molded article having excellent mechanical strength, friction and wear characteristics, mechanical processability, etc., which is obtained by heating and compression molding a polyimide resin composition in which the polyimide resin composition is added. The body is particularly suitable for use as a material for forming functional parts that are used under severe usage conditions such as sliding at high temperatures, high speeds, and high loads.

[Conventional technology]

In recent cutting-edge industrial fields, existing materials are no longer sufficient, and new high-performance functional materials are being sought.

Aromatic polyimide, which has excellent heat resistance, has recently been attracting attention in fields such as electronic parts, copying machines, microwave ovens, automobiles, industrial equipment, aircraft, and nuclear equipment as a material that meets advanced industrial requirements. , has been adopted. Aromatic polyimides take advantage of their heat resistance and are often used for applications under harsh operating conditions such as high temperatures and high sliding conditions.
BACKGROUND ART Compounds containing aromatic polyimide as the main component of the resin are being used to take advantage of their properties such as heat resistance, toughness, abrasion resistance, processability, and radiation resistance. Aromatic polyimides used for applications under these severe usage conditions are generally combined with various fillers and reinforcing materials to make functional composites that meet the required performance. Graphite, polytetrafluoroethylene (PTFE), Mo52, bronze, etc. are known as the above-mentioned fillers that improve the
Carbon fiber is known.

[Problems to be solved by the invention] However, although the composite of aromatic polyimide and glass fiber or carbon fiber has a remarkable reinforcing effect, it also accelerates the wear of the composite material itself during sliding due to frictional wear. It is known to have the disadvantage of wear. Furthermore, although the addition of graphite or PTFE to aromatic polyimide as a filler to improve sliding properties significantly improves sliding properties, a decrease in mechanical strength cannot be avoided, and in practical use, It has the disadvantage that it is extremely susceptible to damage during processing using so-called machine tools, such as drilling and cutting.

[Means for solving problems]

In view of the above-mentioned current situation, the inventors of the present invention have taken advantage of the heat resistance of aromatic polyimide resin to provide highly functional parts that can withstand harsh usage conditions such as high temperatures and sliding at high speeds and high loads. As a result of studying the purpose, we found that a polyimide resin composition in which specific amounts of a specific inorganic fibrous filler and a specific solid lubricant were added to aromatic polyimide resin powder,
It has been found that a molded article that can achieve the above object can be obtained by heating and compression molding.

The present invention was made based on the above findings, and includes a fat powder for aromatic polyimide of 35 to 85% by weight, an average fiber diameter of 0.1
10-40% by weight of an inorganic fibrous filler of ~15 μm and an aspect ratio of 10-100, and an average particle size of 1-30 μm
The object of the present invention is to provide a polyimide resin molded article obtained by heating and compression molding a polyimide resin composition containing 5 to 25% by weight of a solid lubricant.

The aromatic polyimide resin powder constituting the polyimide resin composition used in the present invention is produced by polymerizing and imidizing a tetracarboxylic acid component such as an aromatic tetracarboxylic acid or its acid dianhydride, and an aromatic diamine component. The obtained powder is a heat-resistant aromatic polyimide polymer, or a mixed powder of two or more thereof, and preferably has an average particle size of 1 to 40 μm, particularly 2 to 20 μm.

The aromatic tetracarboxylic acid components include pyromellitic acid, 3.3', 4.4'-biphenyltetracarboxylic acid, 2.3.3', 4°-biphenyltetracarboxylic acid, 3.3', 4.4°-benzophenonetetracarboxylic acid, bis(314-dicarboxyphenyl)ether, bis(3,4-dicarboxyphenyl)thioether, bis(314-dicarboxyphenyl)methane, 2
．． Examples include aromatic tetracarboxylic acids such as 2-bis(3,4-dicarboxyphenyl)propane, dianhydrides of these acids, and mixtures of the above-mentioned compounds. In particular, in the present invention, biphenyl The use of a tetracarboxylic acid component containing tetracarboxylic acid as a main component (containing about 50 mol% or more, especially 70 mol% or more) improves the moldability of the aromatic polyimide resin powder or the physical properties of the molded product. This is preferable from the point of view.

The aromatic diamine components include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylthioether, 4,4'-diaminodiphenylmethane,
4.4'-diaminobenzophenone, 0-, t- or p-
Examples include phenylenediamine, etc., or mixtures thereof, and in particular, in the present invention, 4゜4'-diaminodiphenyl ether is the main component (for example, containing about 40 mol% or more, especially 50 mol% or more, and It is preferable to use an aromatic diamine component (preferably containing 70 mol% or more).

The above-mentioned aromatic polyimide resin powder is not particularly limited in its manufacturing method, and for example, the above-mentioned tetracarboxylic acid component and aromatic diamine component are used in approximately equal moles to form a highly concentrated polyimide resin powder in an organic polar solvent. Either polymerization and imidization are carried out at a polymerization temperature to precipitate a high molecular weight aromatic polyimide resin powder, or the above-mentioned two components are polymerized in an organic polar solvent at a relatively low temperature to produce a high molecular weight aromatic polyamic acid. , adding a polyamic acid-insoluble solvent to the polymerization solution to precipitate aromatic polyamic acid powder, heating the powder to imidize (imide cyclization by dehydration reaction of acid-amide bond of polyamic acid), It is manufactured by a method of manufacturing aromatic polyimide resin powder.

In addition, examples of the inorganic fibrous filler constituting the polyimide resin composition used in the present invention include glass fibers, carbon fibers, potassium titanate whiskers, and ceramic fibers (for example, wollastonite fibers, SiC whiskers, Si3N4
whiskers, etc.), boron fibers, metal fibers (for example, stainless steel fibers, brass fibers, aluminum fibers, etc.), and from these, the average fiber diameter is 0.1 to 15 μm, preferably 0.2 to 15 μm. um and aspect ratio 10-1
00, preferably 15 to 80, one or more types may be appropriately selected and used.

The inorganic fibrous filler can be more easily uniformly dispersed in polyimide powder than organic fibers such as aromatic polyamide fibers, and has excellent microreinforcing properties, cutting properties, and surface smoothness.

If the average fiber diameter of the inorganic fibrous filler exceeds 15 μm, the surface smoothness will deteriorate and the aspect ratio will be 10.
If it exceeds 0, uniform dispersion is extremely difficult, which impairs friction and wear characteristics, resulting in quality deterioration.If the average fiber diameter is less than 0.1 μm, fibers aggregate, making uniform dispersion difficult. Further, if the aspect ratio is less than 10, there is no reinforcing effect, chipping is likely to occur during cutting of the molded body, and machinability is not improved.

The solid lubricants constituting the polyimide resin composition used in the present invention include fluororesin powder, molybdenum disulfide, tungsten disulfide, graphite, talc, lead oxide, graphite fluoride, carbon, mica, and boron nitride. , lead powder, copper powder, bronze powder, silver powder, etc.
From these, the average particle size is 1 to 30 μm, preferably 3 to 2
One or two or more types having a diameter of 0 μm may be appropriately selected and used.

If the average particle size of the solid lubricant exceeds 30 μm, there will be a problem in terms of surface smoothness, and if it is less than 1 μm, the particles will be too fine, resulting in poor adhesion between resins and promoting wear.

The polyimide resin molded article of the present invention contains 35 to 85% by weight of the aromatic polyimide resin powder, preferably 40 to 80% by weight, 10 to 40% by weight, preferably 15 to 40% by weight of the inorganic fibrous filler, and The solid lubricants 5 to 25
A polyimide resin composition obtained by mixing % by weight, preferably 5 to 20% by weight, by a conventionally known method, for example, a dry mixing method using a mixer such as a tumbler mixer or a Henschel mixer, is compression molded. Using a machine etc., under heat and pressure, it can be shaped into wires, rods, plates, sheets, etc.
When molded into any other shape, if the blending ratio of the inorganic fibrous filler is less than 10% by weight, a satisfactory reinforcing effect will not be obtained, and if it exceeds 40% by weight, the surface smoothness will deteriorate. I can't get it.

Further, if the blending ratio of the solid lubricant is less than 5% by weight, the required sliding properties cannot be obtained, and if it exceeds 25% by weight, surface smoothness and friction and wear properties will be impaired.

In the present invention, heating and compression molding of the polyimide resin composition is carried out at temperatures of 250° C. or higher, preferably 300° C., when a ram extrusion molding machine is used as the compression molding machine, for example.
Filling the mold with the polyimide resin composition at a molding temperature of ℃ to 500℃, and heating at 100 to 1500K using a ram.
g/aJ, preferably 150 to 1000 Kg/cd, particularly preferably 150 to 700 Kg/cj, and extruding and compressing the polyimide resin composition into a mold are carried out alternately. Heating the resin composition in the mold v! ! This can be done by gradually extruding a long molded product while the molded product is being coated.

The polyimide resin molded article of the present invention is obtained by heating and compression molding the polyimide resin composition, and has excellent practical performance in terms of friction and abrasion, and is superior to conventional sliding property improving materials. It exhibits an extremely high level of sliding properties that cannot be achieved with molded bodies made of filled resin compositions. A further important effect of the polyimide resin molded article of the present invention is that it can be processed extremely smoothly when cutting and finishing with a machine tool to produce precision parts that require dimensional accuracy or complex shapes. The combination of the inorganic fibrous filler and the solid lubricant and the combination of the inorganic fibrous filler and the solid lubricant as defined in the present invention does not exhibit sufficient machinability when various reinforcing fibers or various slidability improving materials are used alone. Only by heat-compression molding a polyimide resin composition consisting of a blending ratio, a high-performance molded article having a well-balanced property can be obtained.

〔Example〕

EXAMPLES The present invention will be explained in more detail below by giving examples of the present invention together with comparative examples.

Examples 1 to 5 and Comparative Examples 1 to 5 Aromatic polyimide powder obtained by polymerizing and imidizing 3.3°, 4,4°-biphenyltetracarboxylic dianhydride and 4,4”-diaminodiphenyl ether After thoroughly mixing each raw material using a Henschel mixer according to the mixing ratio shown in Table 1 below, using a compression molding machine at a pressure of 300 Kg/c + J and a temperature of 370
The sheets were individually molded under conditions of .degree. Mechanical properties (flexural strength, flexural modulus), frictional wear characteristics (friction coefficient, wear amount), and machinability were measured for each test piece obtained by machining the sheet. The results are shown in Table 2 below.

*5: Manufactured by Kureha Chemical ■Kureka Chosop 101S (average fiber diameter 14.5 μm, aspect ratio 10-30) *6: Manufactured by Kureha Chemical ■Kureka Chop C-1063 (
Average fiber diameter 14.5μm, aspect ratio 200-500
) *7: Asahi Fiberglass Co., Ltd. MFA (average fiber diameter 1) μm, aspect ratio 10-15) *8: Dow Corning Co., Ltd. Molycoat Z (average particle size 4.5 μm) *9: Dow Corning Co., Ltd. Molycoat Micro Size (average particle size 0.7 μm) *10: ACP manufactured by Nippon Graphite Industries (average particle size 13 μm)
m) *1): KTL610 manufactured by Kitamurasha (average particle size 9 μm)
) Table 2 *1: Measured according to ASTM D-790.

*2: Measured according to ASTM D-790.

*3: Measured under the following conditions using a lead powder friction tester.

Speed 10m/min, pv value 100Kg/C1)!・ll1
), Atmosphere: Dry, Compatible material: SUJ 2*4: Measured using a lead powder friction tester under the following conditions.

Speed 128m/min, P v4a 100Kg/cm"-
m/min, dry atmosphere, mating material 5UJ2 *5: Thread cutting was performed using a lathe, and its workability was evaluated.

○... Finished (can be cut).

Δ: Partially chipped during cutting.

×...Thread-shaped cutting cannot be performed.

The following is clear from the results shown in Table 2 above.

The polyimide resin molded bodies of the present invention (sheets obtained in Examples 1 to 5) all have balanced mechanical strength,
It has extremely excellent sliding properties and machinability.

In contrast, sheets molded from polyimide resin compositions in which the amount of inorganic fibrous filler added was outside the limited range of the present invention (Comparative Examples 1 and 3) had poor machinability. . A sheet formed from a polyimide resin composition containing no solid lubricant (Comparative Example 2) had a particularly high coefficient of friction. In addition, a sheet formed from a polyimide resin composition containing an inorganic fibrous filler whose aspect ratio is outside the limited range of the present invention (Comparative Example 4) has a high coefficient of friction and is not improved in machinability. It was something. Furthermore, a sheet molded from a polyimide resin composition containing a solid lubricant with an average particle size smaller than the limited range of the present invention (Comparative Example 5) has improved machinability but very poor wear resistance. Because of its poor quality, it could not be used as a sliding material.

〔Effect of the invention〕

The polyimide resin molded article of the present invention has excellent mechanical strength, friction and wear characteristics, mechanical workability, etc., and has the ability to be used under severe usage conditions such as sliding at high temperatures, high speeds, and high loads. Suitable for use as a forming material for parts.

Claims (3)

[Claims] (1) Aromatic polyimide resin powder 35-85% by weight, average fiber diameter 0.1-15 μm and aspect ratio 10-10
A polyimide resin molding obtained by heating and compression molding a polyimide resin composition consisting of 10 to 40% by weight of an inorganic fibrous filler of 0.0 μm and 5 to 25% by weight of a solid lubricant with an average particle size of 1 to 30 μm. body. (2) The inorganic fibrous filler is glass fiber, carbon fiber,
The polyimide resin molded article according to claim (1), which is one or more selected from the group consisting of potassium titanate whiskers, ceramic fibers, boron fibers, and metal fibers. (3) The solid lubricant is fluororesin powder, molybdenum disulfide, tungsten disulfide, graphite, talc, lead oxide, graphite fluoride, carbon, mica, boron nitride, lead powder, copper powder, bronze powder, and silver powder. The polyimide resin molded article according to claim (1), which is one or more selected from the group consisting of: