JPH03134087A - Heat-resistant friction material and preparation of the same - Google Patents

Abstract

PURPOSE:To improve the friction coefficient, abrasion resistance and mechanical strength of a heat-resistant friction material under the conditions of high temperatures and high loading by filling a mold with a molding mixture comprising an inorganic and/or organic base material, a specific friction-controlling agent and a binder before pressure molding at an elevated temperature. CONSTITUTION:An inorganic base (e.g. glass fiber) and/or an organic base (e.g. aromatic polyamide fiber) is compounded with 1-50 wt.% polyamide-imide resin as a binder and a friction-controlling agent comprising 1-50 wt.% (based on the binder) copper powder having a particle diameter of 0.2 mm or below or a copper foil having a length of 2-1,000 mum, an aspect ratio of 11-50 and a thickness to breadth ratio of 1/3 or below and 5-50 wt.% Sb2O3 powder to yield a molding mixture. The mixture is billed in a mold to conduct pressure molding at an elevated temperature.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a heat-resistant friction material and a method for manufacturing the same.

More specifically, the present invention relates to a heat-resistant friction material that can be suitably used for power transmission or braking of automobiles, and a method for producing the same.

(Prior Art) Conventionally, friction materials used in automobiles include brake linings, disc pads, clutch facings, etc., and asbestos has been used as the base material. However, in recent years, as asbestos is harmful, there has been a desire to develop non-asbestos-based friction materials.In addition, with the improvement of automobile engine performance, the performance of friction materials has been improved, especially materials that can withstand high temperatures and high loads. development is required.

Glass fiber is an alternative to asbestos base material.

Carbon fiber, aromatic polyamide fiber, rock wool.

Friction materials using ceramic fibers, various steel fibers, etc. have been developed and are in use. However, compared to conventional asbestos, these base materials have the drawbacks of thicker fibers, higher elasticity, hardness, and brittleness.

Furthermore, with friction materials made of metal or inorganic fibers other than asbestos, bulky molded products cannot be obtained, and the high heat generated at the friction interface is rapidly conducted throughout the friction material.

There is a problem of accelerated thermal decomposition of the binder.

Therefore, with conventional binders, it has been difficult to obtain a friction material that satisfies all of the friction coefficient, wear rate, and strength under high temperature and high load conditions.

A method for obtaining a friction material that can withstand high temperatures and high loads using an asbestos substitute is a method in which the friction material itself is subjected to high temperature treatment in advance (% 1984-13184-6, JP-A-5
No. 9-113038 and Japanese Patent Application Laid-Open No. 60-145302), but this method has the drawbacks of increased cost and reduced mechanical strength. In addition, a method of adding a special friction modifier (%)
There is also a method (No. 1, Publication No. 2003-11121), but this method does not provide sufficient improvement effects. Furthermore, there is also a method of mixing aramid heat-resistant fibers into the base material [7], adding polyimide resin powder (particles),
In both cases, conventional binders are used to hold the base material and the friction modifier, so the current situation is that sufficient heat resistance cannot be obtained.

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the problems of the prior art and provide a high coefficient of friction even under high temperature and high load conditions.

An object of the present invention is to provide a heat-resistant friction material having wear resistance and mechanical strength, and a method for producing the same.

(Means for Solving Problems 11) As a result, we discovered that all of the above problems can be solved by using copper foil or copper powder as an essential component as a friction modifier and using polyamide-imide resin as a binder. This invention has been achieved.

That is, the present invention provides a heat-resistant friction material containing an inorganic base material and/or an organic base material, a friction modifier, and a binder, wherein the friction modifier includes copper foil or copper powder, antimony trioxide powder, and the binder. The present invention relates to a heat-resistant friction material using polyamideimide resin and a method for producing the same.

Inorganic and/or organic base materials are used as the base material of the present invention. Glass fiber is used as an inorganic base material.

Examples include inorganic fibers such as carbon fiber, rock wool, and ceramic fibers, various metal chips and metal fibers, and phenol fibers as organic base materials.

Examples include organic fibers such as aromatic polyamide fibers.

Among these, glass fiber,
Aromatic polyamide fibers, cast iron chips and steel fibers are preferred.

The friction modifier of the present invention uses copper foil or copper powder and antimony trioxide/powder as essential components.

This significantly improves friction characteristics and heat resistance under high temperature and high load conditions. The copper powder has a particle size of 0.2
W or less is preferable. Also, as a copper foil, the major axis is 2
It is preferable that the diameter is 1000 μm, the aspect ratio determined by the ratio of the major axis to the minor axis is 1 to 50, and the thickness to the minor axis is 1/3 or less.

If the copper powder or copper foil is outside the above range, it may be difficult to uniformly disperse it, which may cause an unstable coefficient of friction.

There are no restrictions on the particle size of antimony trioxide powder, but
In order to obtain the effect of improving friction characteristics, the particle size is preferably 0.2 tm or less.

In addition to copper foil or copper powder and antimony trioxide powder, other inorganic powders and/or organic powders may be used as the friction modifier. As an inorganic powder.

Calcium carbonate, magnesium carbonate, barium sulfate, clay, Merck, graphite, alumina, mica.

Fluorite, zirconia, hematite, magnetite.

Examples include inorganic powders such as silica, antimony sulfide, iron sulfide, and molybdenum sulfide; metal wire powders such as brass, copper, iron, lead, zinc, and aluminum; and organic powders.

Examples include organic substances such as cashew dust, rubber dust, and wood flour.

A polyamideimide resin is used as the binder of the present invention. The polyamide-imide resin is obtained by condensation polymerization of an aromatic diamine and a tricarboxylic anhydride or a conductor thereof.

As the tricarboxylic anhydride, trimellitic anhydride is preferably used, and as the derivative of trimellitic acid anhydride, trimellitic acid or an esterified product of trimellitic acid anhydride and alcohol etc. 9 For example, trimellitic acid anhydride can be used. A methanol half ester compound or the like is used.

Examples of aromatic diamines include m-phenylene diamine, p-7 di-2-diamine, 4.4'-diaminodiphenylpropane, 4.4'-diaminodiphenylmethane, 4.4'-diaminodiphenyl sulfide, 4. 4'
-diaminodiphenylsulfone, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3.
3'-diaminodiphenyl, 3.3'-dimethoxybenzidine, 1,3-diamino-4-inglobylbenzene, xylylenediamine, 4.4''-diaminoterphenyl, 4.4''-diaminoquaterphenyl, 1. 4
-bis(p-aminophenoxy)benzene, 4.4'-
(bis-(p-aminophenoxy)]diphenylsulfone, 4.4'-(bis-(p-aminophenoxy))biphenyl, bis-2-bis(4-(4-aminophenoxy)
Phenyl]propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 44
'-Diaminopenzophenone, benzidine-λ3.5.
Examples include 6-titramethyl-p-7 di-2-diamine, diaminotoluene, tetrafluorophenylenediamine, diaminooctafluorobiphenyl, and the like. These compounds may be used alone or in combination. Among these compounds, considering heat resistance and economic efficiency, 4.4'
It is preferred to use -diaminodiphenylmethane, 4'-diaminodiphenyl ether, p-7 22 diamine or m-phenylenediamine.

To the polyamideimide resin as the binder.

Phenolic resin, melamine resin, epoxy resin.

By adding and modifying or mixing bismaleimide resin, silicone resin, etc. to an extent that does not reduce heat resistance and friction properties, it is possible to improve the holding power of base materials such as glass fibers and friction modifiers such as inorganic powders. .

The content of the binder in the present invention is usually 5 to 50% by weight of the friction material, preferably Vi20 to 45% by weight, from the viewpoint of manufacturing the molded article and the coefficient of friction.

The content of copper powder or copper foil in the present invention is preferably 1 to 50% by weight based on the binder from the viewpoint of lubricating effect and friction coefficient.

The shape of copper is either powder or foil, and the particle size of copper powder is 0.
．． It is 20mm or less, and the aspect ratio (
The ratio of the major axis to the minor axis) is 1 to 50, and the thickness to the minor axis is 1/
It is preferable that the foil has a size of 3 or less and a major axis of 1 to 1000 μm.

The content of antimony trioxide powder in the friction modifier in the present invention is preferably 5 to 50% by weight, more preferably 10 to 30% by weight, based on the binder from the viewpoint of friction coefficient.

A molding mixture containing an inorganic base material and/or an organic base material, a friction modifier, and a binder is filled into a mold and molded under pressure and heat to obtain a friction material.

(Example) The present invention will be explained below with reference to Examples.

Synthetic compounding material of binder for friction materials 9 mol 4.4'-diaminodiphenyl 198 1.0
Methane trimellitic anhydride 192 1.0 Phosphoric acid 6.0 0.06 The above ingredients were placed in a 1 000 mj separable flask equipped with a stirrer, thermometer, cooling tube and nitrogen blowing device, and gradually heated. Then, the temperature was raised to 210'C1, and the reaction proceeded for 17 hours while distilling water off. The progress of the reaction was monitored using a high-performance liquid chromatograph, and the reduced viscosity was 0.5 (dg
/9) (0.5g dimethylformamide ldl
! to obtain a resin solution (measured with a Cannon-Fenske viscometer) at 30°C. This was diluted with N-methylpyrrolidone, the non-volatile content (resin content) was reduced to 25% by weight, and a binder was added.

Example 1 Glass fiber (Fuji Fiber Co., Ltd.; UPGIZA508
) were mixed and stirred, and dimethylformamide was added until the mixture became paste-like. Glass fibers opened with a mixer were added to this paste-like mixture, and the mixture was further stirred to obtain a uniform mixture. The resulting mixture was dropped into water under high-speed stirring, and solvent removal and pulverization were performed simultaneously to obtain a granular mixture. This mixture was then dried at 150° C. for 1 hour to obtain a molding mixture. This mixture was filled into a mold and heated to 290 kg under a pressure of 200 kg f/cm.
A molded product was obtained by heating and molding at ℃ for 10 minutes. Both sides of this molded product were polished with a sander and further heat treated at 250°C for 2 hours to obtain a friction material for testing, and its friction properties were determined using a JIS constant speed tester (friction coefficient and wear rate temperature change). In addition, in order to examine the heat resistance, some of the friction materials for testing were
A heat treatment was applied for 30 minutes in a Matsufuru furnace at 0° C., and the appearance was visually observed. These results are shown in Table 1. It is shown in FIGS. 1 and 2.

Example 2.3 Regarding Example 2.3, molded products were produced and evaluated in the same manner as in Example 1 based on the formulations in Table 1, and the results are shown in Table 1. It is shown in FIGS. 1 and 2.

Comparative Example In Comparative Example 1.2, methanol was used to prepare a paste-like mixture because the resin composition was different from the example according to the formulation shown in Table 1. Also, the drying Fi of the granular mixture is 1 at 90°C.
Time went. Molding pressure 1o.

kg f/am" and a temperature of 160° C. to obtain a molded product. Both sides of this molded product were sanded with a sander and further heat treated at 210° C. for 2 hours.

A test friction material was obtained and evaluated in the same manner as in Example 1, and the results are shown in Table 1. It is shown in FIGS. 1 and 2.

Comparative Examples 3, 4.5 #i Based on the formulations in Table 1, test friction materials were prepared in the same manner as in Example 1, and evaluated. The results are shown in Table 1. It is shown in FIGS. 1 and 2.

≠1 A resin solution was used, but the amount of solid content is shown.

%2 Melamine resin 2 Nippon Carbide Co., Ltd. -260 Pot 3 Phenol resin: Dainippon Ink Co. TD-204
00 Copper foil near aspect ratio 2-3. Short diameter 20~30μ
m, major axis 50 to 60 μm, thickness 1 to 2 μm, Wako Pure Chemical Industries, Ltd. Chemistry Ao 5 Antimony trioxide powder: Wako Tsumugi Kogyo Co., Ltd. Chemical Ao 6 Glass fiber: Opened UPG manufactured by Fuji Fiber Co., Ltd.
IZA508 %7 Inorganic powder: Barium sulfate/talc/calcium carbonate/calcium silicate short fiber = 20/ 20/ 20/ 40 (wt%) Barium sulfate: Sakai Chemical Co., Ltd. Back BC Talc: Wako Pure Chemical Industries Exhibition Chemical Carbonate Calcium: Chemical grade calcium silicate short fiber manufactured by Wako Tsumugi Kogyo Co., Ltd.: Split wollastonite manufactured by NYCO in the United States (effects of the invention) Differences in friction coefficient and wear rate between Examples and Comparative Examples and heat treatment at 400°C for 30 minutes As is clear from the difference in appearance after the process, the friction coefficient and resistance at high temperatures are lower in the system in which polyamide-imide resin is used as a binder and copper foil and antimony trioxide powder are essential components as friction modifiers. A friction material with excellent abrasion properties can be obtained.

In addition, after the 300°C friction test, the sample of the Example only became slightly darker in brown color, whereas the sample of the Comparative Example showed that the binder became porous with thermal decomposition [-carbonization] and became porous. There is. The friction material of the present invention is a friction material with excellent heat resistance and friction properties, and is extremely effective industrially.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing the relationship between the measured temperature and friction coefficient of the example and the comparative example, and FIG. 2 is a diagram of the relationship between the measured temperature and the wear rate of the example and the comparative example.

Claims (1)

[Claims] 1. A heat-resistant friction material containing an inorganic base material and/or an organic base material, a friction modifier, and a binder, wherein the friction modifiers include copper foil or copper powder and antimony trioxide powder;
and a heat-resistant friction material using polyamideimide resin as the binder. 2. The heat-resistant friction material according to claim 1, wherein the polyamide-imide resin is a polyamide-imide resin obtained from 4,4'-diaminodiphenylmethane and trimellitic acid. 3. The content of copper foil or copper powder is 1 to 5 with respect to the binder.
The heat-resistant friction material according to claim 1 or 2, wherein the content is 0% by weight. 4. The heat-resistant friction material according to claim 1, wherein the amount of antimony trioxide powder is 5 to 50% by weight based on the binder. 5. A molding mixture containing an inorganic base material and/or an organic base material, copper foil or copper powder, antimony trioxide powder, and polyamide-imide resin is filled into a mold, and the heat-resistant friction material is molded under pressure and heat. Manufacturing method.