JPH0893815A - Friction material - Google Patents

Abstract

PURPOSE: To improve frictional characteristics of an organic friction material used for a brake pad for an automobile, etc. CONSTITUTION: A thermosetting resin such as phenolic resin, etc., is imparted with such a composition as being compounded with silicon carbide powder, potassium titanate and barium sulfate. Compounding amount of the silicon carbide and the potassium titanate is preferably in a range of approximately 5-40weight% in total, and a ratio (weight ratio) of the silicon carbide powder/ potassium titanate is preferably in the range of approximately 5/1 to 1/1. The barium sulfate may be compounded in the range of approximately 10-50weight%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material having a high coefficient of friction and improved face-to-face damage properties, which is useful as a brake pad material for automobiles.

[0002]

2. Description of the Related Art As a brake pad material for automobiles, asbestos (asbestos fiber) is used as a base material, which is dispersed in a thermosetting resin (typically a phenol resin) and bonded to form a binder. It has been. Recently, non-asbestos type brake pads have been developed from the viewpoint of pollution prevention, and various proposals have been made for asbestos substitutes. However, there are only a few examples in which steel fibers and potassium titanate fibers are used as a base material component, which have been put to practical use. On the other hand, the present inventors
It has been found that silicon carbide (SiC) is useful as a base material component, and in an already filed application, an organic friction material having the same as the base material component was provided (Japanese Patent Application No. 5-322764). As the friction material, about 5 to 40% by weight of silicon carbide powder and about 20 to 50% by weight of barium sulfate powder as a friction modifier are uniformly dispersed in a resin (phenol resin) to prepare a raw material composition, which is heated. -Manufactured by binding and forming under pressure.

[0003]

The above friction material has a high friction coefficient (μ) as a silicon carbide dispersion effect, and its frictional characteristics are relatively stable from a low temperature range to a high temperature range, but face-to-face damage. When used as a brake pad for automobiles, the sliding surface of a disc made of an aluminum alloy composite material (aluminum alloy in which reinforcing fibers are dispersed), etc. is likely to cause damage thinning due to abrasive wear, and braking There is room for improvement in terms of ensuring stability and durability as a member. In view of the above, the present invention is to provide a friction material having improved face-to-face damage resistance without impairing the high wear resistance obtained as a silicon carbide dispersion effect.

[0004]

The organic friction material of the present invention is characterized in that an organic friction material containing barium sulfate and a thermosetting resin as main components contains silicon carbide and potassium titanate. I am trying.

[0005]

FUNCTION Silicon carbide is an extremely hard ceramic, its Mohs hardness is about 9.2, and that of potassium titanate is about 4. The friction material of the present invention maintains a high friction coefficient due to the dispersion effect of silicon carbide, and as a result of the composite dispersion of softer potassium titanate, secures improved face-to-face damage.

As the base component of the friction material of the present invention, the total amount of silicon carbide and potassium titanate to be added to the resin binder is 5 to 40% by weight. The compounding ratio (silicon carbide / potassium titanate) is preferably in the range of 5/1 to 1/1 (weight ratio). The reason why the amount is 5% by weight or more is that if it is less than that, the effect of improving the friction and wear characteristics as the dispersing effect is insufficient. Because. Furthermore, silicon carbide /
The lower limit of the compounding ratio of potassium titanate to be 1/1 is that when the ratio of silicon carbide becomes smaller than that,
It becomes difficult to secure a high friction coefficient as an effect of adding silicon carbide, and the upper limit value is set to 5/1. If the upper limit value is exceeded, the effect of improving face-to-face damage as a combined use of potassium titanate is sufficient. This is because it cannot be done. Further, the compounding amount of barium sulfate compounded in the resin together with the above-mentioned base material component is preferably in the range of 10 to 50% by weight. If it is less than 10% by weight, the effect as a reinforcing material is not sufficient, while if it exceeds 50% by weight, the effect is almost saturated and there is no benefit of further increase in the amount.

As the silicon carbide, those commercially available may be used, and the powder particle size is, for example, 0.1 to 1
It may be 00 μm. Potassium titanate, which is compounded with silicon carbide, is a synthetic inorganic compound having a fibrous or granular shape represented by the general formula K ₂ O.n TiO ₂ .
As a typical example, potassium hexatitanate (K ₂ Ti ₆ O
₁₃ ) and potassium tetratitanate (K
₂ Ti ₄ O ₉ ), potassium octatitanate (K ₂ Ti
₈ O ₁₇ ) or the like, or a mixture thereof, which are fibrous (for example, a diameter of about 1 to 10 μm and a length of about 5).
~ 30 μm), granular (for example, particle size of about 5 to 15 μm)
m) etc. can be used arbitrarily. The barium sulfate added to the resin together with silicon carbide and potassium titanate may be the one usually used as a friction modifier. Incidentally, the base material component, as a surface treatment for improving the dispersibility in the resin and the binding property, if desired,
It is used after being subjected to a coupling treatment with a known silane coupling agent (aminosilane, epoxysilane, mercaptoxylan, etc.) or titanate coupling agent (isopropyltriisostearoyl titanate, etc.).

The preparation of the raw material composition of the friction material of the present invention is the same as that described above except that silicon carbide and potassium titanate are compounded as a base material in the resin and barium sulfate is added thereto. There are no special conditions or restrictions, and various additives (for example, rust preventives, lubricants, abrasives, etc.) are used in appropriate amounts in preparation of the composition (for example, molybdenum disulfide 5% by weight or less). ) Addition is no different from that in the raw material preparation of this type of friction material. As the resin, a phenol resin is a typical example, and in addition, thermosetting resins such as formaldehyde resin, epoxy resin, and silicone resin, or modified thermosetting resins (cashew-modified etc.) thereof can be mentioned.

The binder forming step of the raw material composition prepared to have a predetermined composition is also carried out according to a conventional method. For example, after the preforming, the binder forming is performed under heat and pressure by a mold forming (about 150-).
After demolding at 200 ° C. for about 10 to 40 MPa, heat treatment (about 150 to 200 ° C. for about 1 to 12 Hr) is performed if desired, and then the molded body is subjected to machining and polishing to finish into a friction material.

[0010]

【Example】

[1] Manufacture of test friction material (disk pad) Using the following raw material compositions A and B, preforming (1
After 4.7 MPa, normal temperature, holding time 1 minute), binding molding with a mold (15 MPa, 180 ° C, holding time 5 minutes) was performed, and after demolding, heat treatment was performed in a drying furnace (holding 180 ° C for 3 hours), After that, the friction materials A and B are cut into a predetermined size and polished.
To get Friction material A ... Inventive example (using raw material composition A) Friction material B ... Comparative example (using raw material composition B) [Raw material composition A] Barium sulfate powder ... 50% by weight Silicon carbide powder ... 25% by weight Titanic acid Potassium fiber: 5% by weight Phenolic resin: 20% by weight [Raw material composition B] Barium sulfate powder: 50% by weight Silicon carbide powder: 30% by weight Phenolic resin: 20% by weight

[2] Friction characteristics The friction materials A and B to be tested were subjected to a slide test (however, test stress: 2 MPa, speed: 4 m / S) by a pin-on-disk tester to obtain a friction coefficient (μ). And face-to-face disc (material type: aluminum-Ni alloy composite material, size: φ6
The wear loss (g) of 4) was measured. Table 1 shows the test results. In the table, the wear amount in the "face-to-face damage" column is the test time of 1 hr.
Is a disk wear loss amount (g).

As shown in Table 1, friction material A (invention example)
Shows a high friction coefficient (μ) equivalent to that of the friction material B (Comparative Example), and the wear loss of the facing disk is drastically reduced as compared with that of the friction material B, which shows a remarkable improvement effect on the facing damage. Have

[0013]

[Table 1]

[0014]

The friction material of the present invention has a high coefficient of friction as a result of the combined addition of silicon carbide and potassium titanate, and at the same time has an improved face-to-face damage property. As a brake pad for an automobile, it contributes to the stability and durability of the braking mechanism.

Claims (2)

[Claims] 1. An organic friction material containing barium sulfate and a thermosetting resin as main components, wherein silicon carbide particles and potassium titanate particles are blended. 2. The total blending amount of silicon carbide particles and potassium titanate particles is 5 to 40% by weight, and the blending ratio (weight ratio) of silicon carbide / potassium titanate is 5/1 to 1/1. The friction material according to claim 1, wherein: