JPH09286973A - Non-asbestos-based abrasion material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a non-asbestos-based abrasion material containing calcium fluoride as one component of an abrasion material, reduced in occurrence of noise and aggression to opposite material, excellent in abrasion resistance and economical efficiency and useful as an abrasion material for industrial machines, rolling stocks, automobiles, etc. SOLUTION: This abrasion material consists essentially of (A) a thermosetting resin binder, (B) a non-asbestos-based fiber reinforcing material, (C) an organic abrasion controller, (D) a solid lubricating material and (E) an inorganic filler and further contains (F) calcium fluoride [e.g. having 1.4-1.8g/ml bulk density, 2-3.3 true specific gravity, 4 Moh's hardness, 1350 deg.C melting point, <=300μm maximum particle diameter and especially <=45μm particle distribution]. The abrasion material contains preferably 5-15wt.% component A, 3-15wt.% component B, 3-20wt.% component C, 3-15wt.% component D, 25-70wt.% component E and 2-35wt.% component E, respectively.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a friction material containing calcium fluoride. Specifically, the present invention is a friction material used for friction sliding materials (brake pads, brake linings, clutch facings, etc.) for industrial machines, railway vehicles, luggage vehicles, and automobiles, in which noise generation is significantly suppressed. The present invention relates to a non-asbestos-based friction material excellent in economy.

[0002]

BACKGROUND OF THE INVENTION Friction materials for general brakes and clutches (brake pads, brake linings, clutch facings, etc.) are thermosetting resin binders such as phenol resin, friction modifiers such as resin dust, barium sulfate, etc. It is generally composed mainly of an inorganic filler and a non-asbestos fiber reinforcing material such as an organic fiber, an inorganic fiber and a metal fiber.

As one of the important performances of such a friction material, there is a noise property (the occurrence of brake noise is small). In other words, noise reduction accounts for a large percentage of the market demands for disc brakes, etc., so reduction of noise generation is treated as a major practical problem, and therefore noise is less likely to occur (noise It is an important characteristic of the friction material.

In order to develop a friction material having excellent noise characteristics, various efforts have been made so far. For example,
A method of smoothing friction by adding a solid lubricant such as graphite or molybdenum disulfide to reduce noise, and adding a friction modifier such as cashew dust to improve the damping characteristics of the friction material. There is a method of reducing the generation of noise due to vibration.

However, although these methods achieve noise reduction to some extent, they are still insufficient, and further development of a friction material excellent in noise is desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a non-asbestos-based friction material having excellent noise characteristics and good economical efficiency.

[0007]

As a result of intensive studies, the present inventors have found that the above problems can be solved by using calcium fluoride as one component of the friction material, and have completed the present invention.

That is, according to the present invention, a friction material containing a thermosetting resin binder, a fiber reinforcement, an organic friction modifier, a solid lubricant, and an inorganic filler as a main component contains calcium fluoride. The present invention relates to a characteristic non-asbestos friction material.

The present invention also relates to the non-asbestos-based friction material, wherein the content of calcium fluoride is 2 to 35% by weight based on the total weight of the friction material material. Further, the present invention, the total amount of friction material,
5 to 15 wt% of thermosetting resin binder, 3 of fiber reinforcement
-15 wt%, organic friction modifier 3-20 wt%, solid lubricant 3-15 wt%, inorganic filler 25-70 wt%.

By using calcium fluoride as one of the constituents of the friction material, it is possible to inexpensively obtain the non-asbestos friction material in which the friction vibration is suppressed and the noise is reduced. It is also possible to maintain good wear resistance and reduce the attacking property of the mating material.

[0011]

Embodiments of the present invention will be described below. The non-asbestos-based friction material of the present invention is mainly composed of a thermosetting resin binder, a fiber reinforcing material, an inorganic filler, and an organic friction modifier, and is characterized by containing calcium fluoride. To do.

Calcium fluoride (C used in the present invention
aF ₂ ) is generally called fluorite and is not particularly limited, but specifically, has a bulk density of 1.4 to
1.8 (g / ml: CB-0010, -50mes
h), true specific gravity 2 to 3.3 (air comparison type specific gravity measuring method), Mohs hardness 4, melting point 1350 ° C. are preferable.

The maximum particle size is preferably 300 μm.
Hereafter, those having a particle size distribution of 45 μm or less are more preferably used. Such calcium fluoride is commercially available, and examples thereof include fluorite (trade name: firefly stone Y) manufactured by Kinsei Matec Co., Ltd.

The content of calcium fluoride with respect to the total amount of the friction material is preferably 2-35% by weight, more preferably 5%.
１５15% by weight. When the content of calcium fluoride is within this range, good noise can be maintained without increasing the amount of wear.

The thermosetting resin binder used in the present invention has a role of binding and hardening each compounding component of the friction material, and includes a phenol resin (straight phenol resin and various modified phenol resins such as rubber). ), Melamine resin, epoxy resin, cyanate ester resin and the like are used. Of these, a phenol resin is preferably used. The amount of the thermosetting resin binder used is usually 5 to 15% by weight based on the total amount of the friction material.

The fiber reinforcing material of the present invention includes metal fibers such as copper fibers, brass fibers and steel fibers; aromatic polyamide fibers such as aramid fibers and organic fibers such as flame-resistant acrylic fibers; potassium titanate fibers and glass. Fiber, alumina fiber, carbon fiber, non-asbestos inorganic fiber such as rock wool; and the like. These can be used alone or in combination of two or more. The amount of the fiber reinforcing material used is preferably 3 to 15% by weight, more preferably 3 to 10% by weight, based on the total amount of the friction material.

Examples of the organic friction modifier used in the present invention include resin dust such as cashew dust and melamine dust, and rubber dust. These can be used alone or in combination of two or more. The content of the organic friction modifier with respect to the total amount of the friction material is preferably 3 to 20% by weight, more preferably 3 to 10% by weight.

The solid lubricant used in the present invention includes:
Examples include graphite and molybdenum disulfide. These can be used alone or in combination of two or more. The blending amount of the solid lubricant with respect to the total amount of the friction material is preferably 3 to 15% by weight, more preferably 3 to 10% by weight.

As the inorganic filler used in the present invention,
Hard metal oxide particles such as alumina, silica and zirconia; metal particles such as copper, brass, iron and zinc; scale-like inorganic substances such as vermiculite and mica; inorganic compounds such as barium sulfate, calcium carbonate and magnesium oxide; Used. These can be used alone or in combination of two or more.
The compounding amount of the inorganic filler is preferably 25 to 70% by weight, more preferably 25 to 60% by weight, based on the total amount of the friction material.

As the method for producing the non-asbestos-based friction material of the present invention, all raw material powders of the above-mentioned components are uniformly mixed, and the raw material mixture is heated and pressed (specifically, the raw material mixture is placed in a mold). After pre-molding, move the back plate to the set mold, heat and pressurize to integrally mold with the back plate, and then post-cure) Dry method and all raw material powder in the presence of solvent (wetting agent) There is a wet method in which the wet raw material mixture is mixed and moistened, and the wet raw material mixture is dried, followed by heating and pressure molding, and any method is possible.

The wetting agent used in the wet method is not particularly limited, but a coagulant flocculating agent composed of a water-alcohol mixed solvent is preferably used. Specifically, while dry-mixing the above-mentioned blending components, a coagulant coagulant composed of water-alcohol mixed solvent is added to and mixed with the mixture to wet the raw material mixture and impart viscosity to the wet raw material mixture. Once prepared, the wet raw material mixture is then granulated to form granules and dried to dry granules. By using such a mixed solvent, even if the step of forming the wet raw material mixture into granules in advance and drying it for the purpose of avoiding dust in the drying step is adopted, the granules move during granulation or during drying. It is not destroyed by vibration, etc. The dried granules thus obtained are heated and pressed in a mold in which the back plate is set to be integrally molded with the back plate, and after-cured to obtain a friction material. As the molding conditions in this case, any known conditions can be adopted (Japanese Patent Laid-Open No. 6-136145).
Reference).

[0022]

Embodiments of the present invention will be described below.

[0023]

Examples 1 to 6 and Comparative Example 1 (1) Manufacture of abrasion material test piece Table 1 shows the types and amounts (% by weight) of the raw material components of the friction material test piece used in this example. The calcium fluoride used here is fluorite Y (CaF ₂ 90%, bulk density 1.4 to 1.8 g / c, trade name, manufactured by Kinsei Matec Co., Ltd.).
c, true specific gravity 3.0 to 3.3, Mohs hardness 4, melting point 135
0 ° C., standard number 88 to 95 (nominal size to 45 μm)).

In this Example, a wet-raw material mixture obtained by adding and mixing a water-ethyl alcohol mixed solvent (containing 1 mole of ethyl alcohol to 10 moles of water) while dry mixing these raw material components with a mixer. Is granulated with an extrusion granulator into granules having an average particle size of 5 mm and an average length of 10 mm, and the granules are dried at about 105 ° C until the water content becomes 1.0% or less, and the dried granules are set at 150 ° C. It was filled in a mold, heated and pressed at 400 Kgf / cm ² , and after-cured at 250 ° C. to produce a friction material test piece (brake pad). The thickness of the obtained friction material test piece was 10 mm, and the area of the friction surface was 50 cm ² .

(2) Evaluation of noise property Each of the obtained brake pads (friction material test pieces) was mounted on an actual vehicle, run at a speed of 40 km / h, and the noise generation level due to vibration at a deceleration of 0.4 G was sensed. A test was conducted to evaluate noise characteristics. That is, the noise generation level is evaluated on a scale of 5 from 1 to 5, with 1 to 2 points being "noise property: ◎" and 3 points being "noise property:
◯, 4 to 5 points were designated as “noise property: x”. The results are shown in Table 1.

[0026]

[Table 1]

As can be seen from the results in Table 1, the friction material obtained by blending calcium fluoride has a low level of vibration generation and good noise characteristics.

[0028]

INDUSTRIAL APPLICABILITY The non-asbestos-based friction material of the present invention is a friction material having excellent economical efficiency and good noise characteristics. Further, it is a friction material having good wear resistance and reduced attacking property of the mating material.

Claims (3)

[Claims] 1. A friction material containing a thermosetting resin binder, a non-asbestos fiber reinforcing material, an organic friction modifier, a solid lubricant, and an inorganic filler as a main component, which contains calcium fluoride. And non-asbestos friction material. 2. The non-asbestos-based friction material according to claim 1, wherein the content of calcium fluoride is 2 to 35% by weight based on the total weight of the friction material. 3. A thermosetting resin binder in an amount of 5 to 15% by weight, a fiber reinforcing material in an amount of 3 to 15% by weight, an organic friction modifier in an amount of 3 to 20% by weight, and a solid lubricant in an amount of 3 based on the total amount of the friction material. % To 15 wt% and 25 to 70 wt% inorganic filler.
Alternatively, the non-asbestos-based friction material described in 2.