JPH02272083A - Non-asbestos friction material - Google Patents

Abstract

PURPOSE:To obtain the subject friction material having high strength, high abrasion resistance at high temperature, improved faderesistance at high temperature and long life by mixing a fibrous substrate containing inorganic fiber consisting of Si-Ti-C-O compound, a friction-controlling agent and a thermosetting resin. CONSTITUTION:The objective friction material can be produced by mixing (A) a fibrous substrate containing preferably 40-80wt.% of an inorganic fiber consisting of Si-Ti-C-O compound (preferably having a fiber diameter of 8-12mum and fiber length of 0.1-3mm), (B) a friction-controlling agent selected from graphite, cashew dust, barium sulfate, etc., and (C) a thermosetting resin such as phenolic resin, melamine resin or epoxy resin.

Description

[Detailed Description of the Invention] [Industrial Application Field] Conventionally, the mainstream of this type of friction material was a friction material using asbestos as a fiber base material, but recently there has been an emphasis on improving the working environment and preventing asbestos pollution. Therefore, the development of non-asbestos friction materials is progressing.

Non-asbestos fiber base materials include inorganic fibers such as glass fibers, alumina fibers, rock wool, and potassium titanate fibers, metal fibers such as steel fibers, copper fibers, and brass fibers, or cotton, rayon, acrylic, and phenolic fibers. The use of organic fibers alone or in combination as a friction material is being considered.

For example, Japanese Patent Application Laid-Open No. 58-72738 describes a thermal conductivity method using steel fibers and carbon fibers for brake pads or brake linings in order to improve the high thermal conductivity of conventional semi-metallic friction materials made of steel fibers and graphite. A method for manufacturing a friction material with low conductivity and long life is disclosed.

Further, JP-A-57-8/5877 discloses a friction material in which glass fibers and heat-resistant organic fibers such as aromatic polyamide fibers are bonded with a thermosetting resin.

[Problems to be Solved by the Invention] However, the method for producing a friction material disclosed in JP-A-58-72738 contains carbon fibers, so it is not suitable for friction materials that require a higher coefficient of friction. Therefore, there has been a demand for improvement. In addition, carbon fiber has poor wetting properties with binders such as phenolic resins, and as vehicles become faster and engines run at higher speeds, there is a problem in that the wear of the friction material increases and the lifespan of the friction material is shortened. .

Furthermore, heat-resistant organic fibers such as aromatic polyamide fibers used in the friction material disclosed in JP-A No. 57-85877 are more heat resistant than general organic fibers, but they can be used to speed up vehicles, etc. There is a problem in that the friction coefficient decreases (fade) under conditions where the temperature of the sliding surface during braking increases significantly.

[Means for Solving the Problems] The present invention solves the above problems and provides a non-asbestos friction material that has a high coefficient of friction at high temperatures, excellent wear resistance and strength.

That is, the present invention provides a non-asbestos friction material comprising at least a fiber base material, a friction modifier, and a thermosetting resin, in which the fiber base material contains inorganic fibers consisting of 5i-Ti-C-0 system. It is a non-asbestos friction material with the following characteristics.

The inorganic fibers made of 5i-TI-C-0 used in the present invention are polydiphenylsiloxane, which is produced by polycondensing diphenyldichlorosilane and boron to polydimethylsilane, which is synthesized by dechlorination polycondensation reaction of dimethyldichlorosilane. obtain. Furthermore, a titanium compound is added to this and subjected to heating polycondensation to obtain an organometallic cross-linked polymer called polytitanocarbosilane.

It is an inorganic fiber obtained by melt-spinning the polytitanocarbosilane, heat-treating the resulting spun fiber to make it infusible, and then firing it in a non-oxidizing atmosphere.

The inorganic fiber consisting of 5i-Ti-co system has a fiber diameter of 5 to
15-1 The fiber length is 0.1 to 6 Iall, preferably the fiber diameter is 8 to 12 m, and the fiber length is 0.1 to 3 mm.

In addition, the blending amount of this fiber is 40 to 40% of the total amount of fiber base material.
80% by weight is preferred.

Fiber base materials other than inorganic fibers made of Si-Ti-C-0 system include inorganic fibers such as glass fibers, silica fibers, alumina fibers, rock wool fibers, potassium titanate fibers, steel fibers, copper fibers, and brass fibers. , metal fibers such as zinc fibers, and organic fibers such as hemp, cotton, rayon, phenol fibers, and aromatic polyamide fibers.
Fibers of more than seeds can be used.

As the friction modifier of the present invention, at least one of graphite, cashew dust, rubber dust, barium sulfate, diatomaceous earth, alumina, dolomite, and calcium carbonate is used.

The thermosetting resins used in the present invention include phenolic resins, melamine resins, epoxy resins, polyester resins, phenol-modified melamine resins, and oil, rubber, melamine, epoxy, or polyvinyl butyral-modified phenolic resins. Or a mixture of two or more.

[Function] In the non-asbestos friction material of the present invention, the 5i-Ti-C-0 inorganic fibers contained as the fiber base material not only have good strength and heat resistance of the fibers themselves, but also Since it has good compatibility (wettability) with the thermosetting resin used as a binder, it improves abrasion resistance and strength at high temperatures, stabilizes the coefficient of friction, and improves fade resistance.

[Example] The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

(Example 1) 5i-Ti-C-0 inorganic fibers (bleached fiber diameter 8.5 mm, fiber length 3.0 mm) were placed in a V-type blender as a fiber base material.
10 parts by weight of short brass fibers (fiber diameter 30°, fiber length 2.0101) were mixed and defibrated for 20 seconds.

In addition, 10 parts by weight of graphite, 8.1 parts of cashew dust
1 part by weight, 27 parts by weight of barium sulfate, and a part by weight of powdered phenolic resin xol were mixed for 15 minutes to obtain a mixed material. Apply this mixed material to a surface pressure of 300 kg/c at room temperature.
Preforming was performed for 20 seconds using a molding machine adjusted to m2 to obtain a preformed product. Thereafter, pressure molding was performed for 5 minutes using a molding machine with a surface pressure of 300 kg/ca + 2 and a mold temperature of 150°C.

Thereafter, it was heat-treated in a heating furnace at 250° C. for 3 hours, left to cool, and then polished to a predetermined size to obtain a friction material for brake pads.

(Example 2) The fiber base material was made of 35 parts by weight of Si-TI-C-0 inorganic fibers and steel IA fibers (fiber diameter 30.0, fiber length 2.0).
mm) A friction material for a brake pad was obtained in the same manner as in Example 1 except that the amount was 10 parts by weight.

(Example 3) The fiber base material was 30 parts by weight of 5l-Ti-C-0 inorganic fiber,
Brass fiber 10! ! A friction material for a brake pad was obtained in the same manner as in Example 1, except that the amount was 5 parts by weight of aromatic polyamide fiber (!a fiber diameter: 12.0 m, fiber length: 2.0 mm).

(Example 4) Fiber base material 5N-Tt-C-0 series ml fiber 20 I!
A brake pad was prepared in the same manner as in Example 1, except that 10 parts by weight of brass fiber, 5 parts by weight of aromatic polyamide fiber, and 10 parts by weight of glass fiber ($a fiber diameter 12.0 m, fiber length 3.0 ma+) were used. A friction material for use was obtained.

(Comparative Example 1) The fiber base material was 10 parts by weight of brass fiber and 5 parts by weight of aromatic polyamide m fiber. A friction material for a brake pad was obtained in the same manner as in Example 1 except that the amount of glass fiber was 1 part and the glass fiber was 30 parts by weight.

(Comparative Example 2) A friction material for a brake pad was obtained in the same manner as in Example 1, except that the fiber base material was 10 parts by weight of brass fibers, 10 parts by weight of aromatic polyamide fibers, and 25 parts by weight of glass fibers.

Regarding the friction materials for brake pads obtained in Examples 1 to 4 and Comparative Examples 1 to 2, a sliding speed of 6.
1m/s, surface pressure 10, 5 kgf/cm2, rotor temperature before braking is 100t:, 200t, 300t, 40
The wear rate was measured at 0°C and 500°C to evaluate the wear resistance. Also, in the same full-size dynamometer test machine,
In accordance with JASO-C406-82, the rotor temperature before braking is 100t, 200t', 300t:, 400℃,
The friction coefficient at 500°C was measured. These results are shown in Table 1.

(Leaving space below) Table 1 As is clear from Table 1, the friction materials for brake pads of Examples 1 to 4 have lower wear rates than the friction materials of Comparative Examples 1 to 2, especially at temperatures above 300°C. is remarkable. Further, regarding the friction coefficient, it can be seen that the friction materials of the examples show little change due to temperature and have good fade resistance at high temperatures (particularly 400° C. or higher).

Although an example in which the present invention is applied to a brake pad has been described, similar effects can be obtained when applied to friction materials such as brake shoes and clutch facings.

[Effects of the Invention] As explained above, the non-asbestos friction material of the present invention has high strength and high temperature resistance by containing inorganic fibers made of Si-Ti-C-0 system in the fiber base material. It is a long-life friction material with improved wear resistance and stable friction coefficient, which improves fade resistance at high temperatures.

Patent applicant: Aisin Kako Co., Ltd. Representative Haruo Miyaji

Claims (1)

[Claims] In a non-asbestos friction material consisting of at least a fiber base material, a friction modifier and a thermosetting resin, the fiber base material is Si-T
A non-asbestos friction material characterized by containing inorganic fibers consisting of i-C-O system.