FRICTION MATERIAL COMPOSITION, FRICTION MATERIAL AND FRICTION MEMBER USING THE SAME

Abstract

The friction material composition has superior conductivity of a friction material, superior adherence of a coating during powder coating, superior film formation of coating and superior abrasion resistance without containing copper having serious environmental effects, the friction material composition includes a binder, an organic filler material, an inorganic filler material, and a fibrous substrate material, wherein the friction material composition contains 8 to 35 mass % of ferrosoferric oxide (Fe.sub.3O.sub.4).

Claims

1. A friction material composition comprising: a binder, an organic filler material, an inorganic filler material, and a fibrous substrate material, wherein the friction material composition contains no copper as an element, or contains not more than 0.5 mass % of copper and 8 to 35 mass % of ferrosoferric oxide.

2. The friction material composition according to claim 1, wherein average particle diameter of the ferrosoferric oxide is 0.1 to 1.0 μm.

3. A friction material which is formed by forming the friction material composition according to claim 1.

4. A friction member which is formed by the friction material formed by the friction material composition according to claim 1 and a backing metal.

5. A friction material which is formed by forming the friction material composition according to claim 2.

6. A friction member which is formed by the friction material formed by the friction material composition according to claim 2 and a backing metal.

Description

EXAMPLES

[0038] Hereinafter the friction material composition, friction material and friction member of the present invention are further explained in detail by way of Examples and Comparative Examples; however, the present invention is not limited thereto.

Examples 1 to 4 and Comparative Examples 1 to 3

(Preparation of Disk Brake Pad)

[0039] Each of the materials was added in an addition ratio shown in Table 1, friction material composition of Examples 1 to 4 and Comparative Examples 1 to 3 were obtained. The addition ratio in the Table is shown by mass %. Ferrosoferric oxide used in Examples and Comparative Examples were as follows.

[0040] Ferrosoferric oxide 1: trade name BP-302S, produced by TODA KOGYO CORP., average particle diameter 0.6 μm

[0041] Ferrosoferric oxide 2: trade name BP-306A, produced by TODA KOGYO CORP., average particle diameter 0.2 μm

[0042] This friction material composition was mixed by a Loedige mixer (trade name: Loedige mixer M20, produced by MATSUBO corporation), and the mixture obtained was preliminarily formed by a forming press (produced by Oji Machine Co., Ltd). The preliminarily formed material obtained was formed while being heated and pressed together with an iron backing metal (produced by Hitachi Automotive Systems, Ltd.) by a forming press (produce by SANKI SEIKO CO., LTD.) at a forming temperature of 140 to 160° C., at a forming pressure of 30 MPa and for a forming time of 5 minutes. The formed product obtained was heat treated at 200° C. for 4.5 hours, and was polished by using a rotary polish apparatus to obtain disk brake pad of Examples 1 to 4 and Comparative Examples 1 to 3. It should be noted that in Examples and Comparative Examples, a disk brake pad in which thickness of the backing metal is 6 mm, thickness of the friction material is 11 mm, and projected area of the friction material is 52 cm.sup.2 was prepared.

(Evaluation of Powder Coating)

[0043] The disk brake pads of Examples 1 to 4 and Comparative Examples 1 to 3 prepared as explained above were powder coated by using an electrostatic powder coating apparatus (trade name: SFC-QTR100, produced by ASAHI SUNAC CORPORATION), and they were evaluated with respect to coating thickness of the backing plate (backing metal) and extent of powder coating at a side surface of the friction material as shown below. The coating thickness of the backing plate was measured by a dual type coating thickness measurer (trade name: LZ-200J, produced by Kett Electric Laboratory). With respect to the measurement results, a case in which the coating thickness of the backing plate was more than 20 μm was evaluated as “Good”, a case in which the coating thickness was 10-20 μm was evaluated as “Satisfactory” and a case in which the coating thickness of the backing plate was less than 10 μm was evaluated as “Unsatisfactory” in Table 1. In addition, visual inspection was also performed, and at the side surface of the friction member, a case in which the friction material was coated by coating and the friction material was not visible was evaluated as “Satisfactory”, and a case in which the friction material was exposed and the friction material was visible was evaluated as “Unsatisfactory” in Table 1.

(Evaluation of Abrasion Resistance)

[0044] The abrasion resistance was measured based on JASO C427 of standard of Society of Automotive Engineers of Japan, Inc, and amount of abrasion of the friction material was evaluated in a case corresponding to 1000 times of braking under conditions of brake temperature 100° C., vehicle velocity 50 km/h, and deceleration 0.3 G, as an abrasion resistance at low temperature. Evaluation was performed at inertia of 7 kgf.Math.m.Math.sec.sup.2 using a dynamo meter. Furthermore, evaluation was performed using a ventilated disk rotor (material: FC190, produced by KIRIU CORPORATION) using a caliper of collet type of general pin slide type. The results are also shown in Table 1.

TABLE-US-00001 TABLE 1 Examples Comparative Examples 1 2 3 4 1 2 3 Ferrosoferric Ferrosoferric oxide 1 10 20 30 0 0 40 0 oxide Ferrosoferric oxide 2 0 0 0 20 0 0 0 Inorganic filler Potassium titanate (TXAX-MA, 18 18 18 18 18 8 18 produced by KUBOTA corporation.) Barium sulfate 15 5 0 5 25 0 15 Zirconia (BR-QZ, produced by 15 15 10 15 15 10 15 DAIICHI KIGENSO KAGAKU KOGYO CO., LTD.) Mica 5 5 5 5 5 5 5 Graphite (T150, produced by 5 5 5 5 5 5 5 TIMCAL) Calcium hydroxide 5 5 5 5 5 5 5 Organic filler Cashew dust 4 4 4 4 4 4 4 Tire rubber powder 5 5 5 5 5 5 5 Binder Phenol resin 8 8 8 8 8 8 8 Fibrous substrate Aramid fiber 5 5 5 5 5 5 5 material Mineral fiber 5 5 5 5 5 5 5 Copper fiber 0 0 0 0 0 0 10 Evaluation of Thickness of coating of backing plate Satisfactory Good Good Good Unsatisfactory Good Good powder coating Side surface of friction material Good Good Good Good Unsatisfactory Good Good Abrasion Abrasion at 100° C. (mm) 0.10 0.11 0.11 0.10 0.15 0.30 0.12 resistance

[0045] With respect to evaluation of powder coating, Examples 1 to 4 in which copper was not contained and ferrosoferric oxide was contained at 8 to 35 mass % were superior to Comparative Example 1 not containing copper and ferrosoferric oxide. With respect to evaluation of abrasion resistance, Examples 1 to 4 were superior to Comparative Example 2 containing more than 35 mass % of ferrosoferric oxide. From the results, it is obvious that Examples 1 to 4 have the same or superior performance on powder coatings and abrasion resistance than the friction material (Comparative Example 3) containing copper.

[0046] The friction material composition of the present invention is appropriate for a friction material and friction member of brake pad or the like for vehicles, since the friction material composition exhibits sufficient coating adherence during powder coating, good film formation of coating and superior abrasion resistance compared to a conventional product without containing copper, which has serious environmental effect.