JP2000204349A - Friction material composition and friction material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction material composition that is suitable for the friction material that has a stabilized friction coefficient and can suppress the occurrence of noises and judder and provide a friction material using the composition. SOLUTION: This composition comprises 0.3-23 wt.% of glassy carbon and 0.1-15 wt.% of titanium carbide in the whole composition. In addition, the objective friction material can be obtained by pressure-forming the friction material composition with heat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material composition suitable for a friction material such as a disc brake pad and a brake lining used for braking automobiles, railway vehicles, various industrial machines and the like, and a friction material composition. Related to friction material.

[0002]

2. Description of the Related Art Friction materials such as disc brake pads and brake linings are used in automobiles, railway vehicles, various industrial machines and the like for braking. Conventionally, as this friction material, Japanese Patent Application Laid-Open No.
As shown in JP-A-117985, semi-metallic friction materials containing steel fibers as a main constituent fiber were the mainstream, but automatic vehicles were launched in line with the shift to lighter and more sophisticated automobile industries. Problems such as generation of abnormal noise at the time of stoppage and stoppage, insufficient braking force at low temperatures, and wheel contamination due to abrasion powder have come up. The abnormal noise generated here has a speed of 30 km /
This is noise (sound pressure of 70 dB or more) associated with braking of the friction material that appears in the process of decelerating from about time, and is a sound of a frequency of about 100 (Hz) in a region where a passenger feels uncomfortable.

[0003] In order to solve these problems, non-ferrous metal fibers such as copper fiber and brass fiber are used instead of steel fiber.
The transition to non-steel friction materials using abrasives of inorganic materials to obtain organic fibers and inorganic fibers such as aramid fibers, ceramic fibers, and more stable friction coefficient (μ ≧ 0.42) has rapidly progressed. .

In the prior art, the friction coefficient has been stabilized by the above-mentioned inorganic material abrasive. However, the abrasive attacks the metal (rotor) of the counterpart material, and in the process, squeal noise and abnormal noise are generated. There is a disadvantage that noise such as sound and judder are generated. At present, a friction material having a stable friction coefficient and completely suppressing generation of noise and judder using an abrasive mainly composed of an organic material including an inorganic material has not been obtained.

[0005]

The invention according to claim 1 provides a friction material composition suitable for a friction material having a stable friction coefficient and capable of suppressing generation of noise and judder. It is. The invention described in claim 2 provides a friction material having a stable friction coefficient and capable of suppressing generation of noise and judder.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a friction material composition comprising 0.3 to 23% by weight of glassy carbon and 0.1 to 15% by weight of titanium carbide in the total composition. Further, the present invention relates to a friction material obtained by subjecting the above-mentioned friction material composition to heat and pressure molding.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the content of glassy carbon in the total composition is from 0.3 to 23% by weight, preferably from 0.5 to 22% by weight, more preferably from 2 to 20% by weight. When the content is less than 0.3% by weight, the effect as a grinding agent does not function sufficiently, and a stable friction coefficient cannot be obtained. On the other hand, if it exceeds 23% by weight, generation of noise and judder cannot be suppressed. The glassy carbon is obtained by, for example, curing a liquid thermosetting resin, and then performing carbonization and high-temperature treatment (graphitization treatment) in an inert atmosphere. In the present invention, the thermosetting resin is cured. Before the titanium carbide is uniformly mixed, a heat treatment is carried out to harden the titanium carbide, followed by a carbonization and high-temperature treatment (graphitization treatment) in an inert atmosphere. The particle size of the pulverized glassy carbon is preferably 1 to 15 μm,
11 μm is more preferred.

The thermosetting resin for obtaining the glassy carbon is not particularly limited, and examples thereof include a furan resin, a phenol resin, an epoxy resin, an unsaturated polyester resin, a melamine resin, an alkyd resin, and a xylene resin. . Further, a mixture of the above resins may be used. In the present invention, a curing agent such as trichloroacetic acid, paratoluenesulfonic acid, and sulfuric acid is added as necessary in addition to the thermosetting resin. When a curing agent is added as necessary, the mixing ratio of the thermosetting resin and the curing agent is preferably in the range of 0.3 to 10 parts by weight of the curing agent per 100 parts by weight of the thermosetting resin. More preferably, the curing agent is in the range of 0.3 to 7 parts by weight based on 100 parts by weight of the conductive resin.

[0009] The content of titanium carbide is 0.1% in the total composition.
It is in the range of 15 to 15% by weight, preferably 1 to 13% by weight, more preferably 3 to 10% by weight, and if it is less than 0.1% by weight, a stable friction coefficient cannot be obtained. One
If it exceeds 5% by weight, generation of noise and judder cannot be suppressed.

[0010] The friction material composition of the present invention comprises, in addition to glassy carbon and titanium carbide, a binder, a reinforcing fiber, a lubricant,
A filler or the like is used, and a metal powder such as brass or bronze is used if necessary. The binder used in the present invention is a phenol resin, an epoxy resin, a melamine resin or the like is used, among which it is preferable to use a phenol resin,
In particular, it is preferable to use a novolak resin, a solid ammonia resol resin, a silicon-modified phenol resin, or an acrylic-modified rubber phenol resin. In the present invention, a curing agent is added to the binder as needed. The binder is preferably contained in the total composition in an amount of 5 to 20% by weight, and 8 to 14% by weight.
More preferably, it is contained by weight. Further, as a curing agent added as needed, hexamethylenetetramine, paraformaldehyde, trioxane, or the like is used, and the content is preferably 8 to 14% by weight in the binder,
More preferably, the content is 12% by weight.

Examples of the reinforcing fibers include inorganic fibers such as glass fibers, ceramic fibers, carbon fibers, and mineral fibers; organic fibers such as aramid fibers, polyamide fibers, and polyimide fibers; and metal fibers such as copper fibers, brass fibers, and steel fibers. Used. The reinforcing fiber is preferably contained in the entire composition in an amount of 0.5 to 16% by weight, more preferably 3 to 10% by weight. The length of the reinforcing fiber varies depending on the material. For example, the inorganic fiber preferably has a length of 15 to 50 mm, more preferably 20 to 45 mm. Organic fibers are preferably 0.8-4 mm,
1-2 mm is more preferred. The metal fiber is preferably 1 to 5 mm, more preferably 2 to 4 mm.

As a lubricant, graphite, antimony sulfide, molybdenum sulfide and the like are used. As a filler, cashew dust, rubber dust, barium sulfate, calcium carbonate, magnesium carbonate, silica and the like are used alone or in combination of two or more. Can be The lubricant is preferably contained in the entire composition at 2 to 8% by weight, more preferably at 3 to 6% by weight. The filler is preferably contained in the entire composition in an amount of 10 to 70% by weight, more preferably 20 to 60% by weight. Further, the metal powder to be added as necessary is preferably contained in an amount of 1 to 8% by weight in the whole composition.
More preferably, the content is about 6% by weight. The use ratio of each component constituting the friction material composition is such that the total amount thereof is 10
It is adjusted to be 0% by weight.

The friction material composition according to the present invention is manufactured by mixing the respective components in an appropriate order. The preliminary composition is obtained by pulverizing the titanium carbide-containing glassy carbon obtained through a predetermined step. Preferably, it is produced by blending and mixing other materials with the preliminary composition. Further, the friction material according to the present invention can be obtained by inserting and filling a back metal and a friction material composition in a mold, molding by a heat-press molding method, and then performing a heat treatment. The heating temperature during molding is 1
30-170 degreeC is preferable and 140-160 degreeC is more preferable. The pressure is preferably 30 to 60 MPa, and 45 to 55 M
Pa is more preferred. The heat treatment temperature is preferably from 100 to 300C, more preferably from 150 to 250C.

[0014]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. Examples 1 to 9 and Comparative Examples 1 to 8 Resor-type furan resins (manufactured by Hitachi Chemical Co., Ltd., trade name V
P-13N) and titanium carbide powder were blended in the amounts shown in Tables 1 and 2, mixed uniformly, put into a warmer, heated to 160 ° C. at a rate of 10 ° C./hour, and heated at 160 ° C. to 5 ° C. After holding for a time, a curing treatment was performed to obtain a titanium carbide-containing resin plate.

Next, the titanium carbide-containing resin plate is carbonized and calcined at 1000 ° C. for 30 days in a nitrogen gas atmosphere, then heated to 2000 ° C., and held at 2000 ° C. for 10 hours for graphitization. Thus, a glassy carbon containing titanium carbide was obtained. The obtained titanium carbide-containing glassy carbon has a thickness of 3.0 mm, a density of 1.58 g / cm ³ , and an electrical resistivity of 90.
1.000 μΩ-cm and a coefficient of thermal expansion of 20 to 400 ° C.
It was 6 × 10 ⁻⁶ deg ⁻¹ .

The titanium carbide-containing glassy carbon obtained above was pulverized to obtain a preliminary composition comprising titanium carbide-containing glassy carbon powder having an average particle diameter of 7 μm. Next, the other materials were added to the preliminary composition in the amounts shown in Tables 1 and 2, and uniformly mixed with a mixer to obtain a friction material composition. Thereafter, a backing metal and a friction material composition are inserted and filled in a mold, and then heated and pressed at 140 ° C. and a pressure of 40 MPa for 12 minutes, and further heat-treated at 200 ° C. for 5 hours to form a disc brake pad. I got

[0017]

[Table 1]

[0018]

[Table 2]

Next, a comparative test was performed on the disc brake pad according to the present invention and the disc brake pad of the comparative example. The test results are shown in Tables 3 and 4. The test conditions are as follows. Shear strength The strength at 22 ° C and 300 ° C was measured according to JASO C427. Wear resistance Caliper model: Collet type (cylinder area 28.8
cm ² ) Test conditions: Inertia ... 4 according to JASO C427
9kgm ² , initial braking speed: 60km / h, deceleration: 2.94
m / sec. ^2, braking before temperature ... 250 ℃, braking number of times ... each 100
The wear amount was measured under the condition of every 0 times.

Abnormal noise generation situation and effectiveness JASO C402 was tested on a 2000 cc automatic car (Nissan Motor Co., Ltd., model name Cedric (Y33)), and the abnormal noise during the test was measured. The occurrence rate of abnormal noise and the maximum sound pressure were determined. As for the effect, the effect as a disc brake during the test is expressed in μ value,
The amount of attack on the surface of the mating material was evaluated based on the amount of grinding of the rotor. Formability The appearance of the disc brake pad was visually observed, and the occurrence of wrinkles and cracks was observed.

[0021]

[Table 3]

[0022]

[Table 4]

As shown in Table 3, it was confirmed that the disc brake pad according to the present invention was free from wrinkles and cracks and was excellent in all properties. On the other hand, as shown in Table 4, the disc brake pads of Comparative Examples 1 and 4 were effective, and the disc brake pads of Comparative Examples 2, 5, and 7 were the actual vehicle abnormal noise generation rate, the actual vehicle abnormal noise maximum sound pressure, and the effectiveness. The disc brake pads of Comparative Examples 3 and 8 show the actual vehicle abnormal noise occurrence rate, the actual vehicle abnormal noise maximum sound pressure, and the attack amount of the opponent material, and the disc brake pads of Comparative Example 6 show the effectiveness and the opponent material. There was a defect in the amount of surface attack.

[0024]

The friction material composition according to the first aspect can provide a friction material having a stable friction coefficient (μ ≧ 0.42) and capable of suppressing generation of noise and judder. . The friction material according to claim 2 has a stable friction coefficient (μ ≧ 0.42) and can suppress generation of noise and judder, and is industrially extremely suitable.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 3/14 520 C09K 3/14 520M 530 530G C08J 5/14 CFB C08J 5/14 CFB F16D 69/02 F16D 69/02 BF // C08K 3/04 C08K 3/04 3/14 3/14 C08L 61/00 C08L 61/00 F term (reference) 3J058 BA21 BA75 BA76 FA01 FA11 FA21 FA31 FA35 GA07 GA20 GA27 GA28 GA34 GA37 GA45 GA55 GA65 GA92 GA95 4F071 AA41 AB03 AB11 AF28 AH07 DA01 DA13 DA15 4J002 CC041 CC071 CC181 DA016 DB017 GN00

Claims (2)

[Claims] 1. A glassy carbon in a total composition of 0.3 to 2%.
A friction material composition containing 3% by weight and 0.1 to 15% by weight of titanium carbide. 2. A friction material formed by heating and pressing the friction material composition according to claim 1.