JP2602369B2 - Heat resistant friction material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant friction material having excellent wear resistance and durability at high temperatures. This friction material is particularly useful as a friction material for brake linings and a facing material for resin molds. is there.

[0002]

2. Description of the Related Art A friction material made of glass fiber as a base fiber and bonded with a thermosetting resin such as a phenol resin,
As it has high strength and excellent wear resistance, and can exhibit high braking force and torque transmission force over a relatively wide temperature range, it is used as various friction materials for brake lining, clutch facing, etc. Widely used.

[0003]

However, since the glass fiber has a relatively low softening point, it cannot be said that the strength characteristics and friction characteristics at high temperatures are sufficient, and the fade phenomenon (commonly referred to as "fiber") occurs after a relatively short use. (Sometimes called "falling")
And lose its function as a friction material.

[0004] In order to improve such disadvantages, attempts have been made to improve high-temperature characteristics by using an appropriate amount of potassium titanate fiber (whisker) together with glass fiber (Japanese Patent Laid-Open No. 63-280966). However, especially in the high-temperature friction characteristics, the expected effect of the modification cannot be obtained, but rather the tendency tends to be worse.

The present invention has been made in view of the above circumstances, and is particularly useful for a brake lining or clutch facing, which require strength, wear resistance and braking durability at high temperatures. It is intended to provide an abrasive friction material.

[0006]

Means for Solving the Problems The structure of the heat resistant friction material according to the present invention which can solve the above problems is a friction material comprising a thermosetting resin as a binder and a glass fiber blended with the binder. Thermosetting resin: 10 to 30% by volume glass fiber and plate-like potassium titanate: containing a total of 45 to 20% by volume, and the blending amount of the glass fiber is 15% by volume or more in the total amount of the friction material. In addition, the gist is that a plate-like potassium titanate having a volume ratio of 1/3 or more with respect to the glass fiber is blended.

[0007]

As described above, it is known to use an appropriate amount of potassium titanate fiber together with a glass fiber base material in order to increase the high-temperature strength as a friction material. However, it has been confirmed that the use of plate-like potassium titanate instead of potassium titanate fiber can effectively enhance high-temperature strength and high-temperature friction characteristics.

For example, FIGS. 1 and 2 show temperature, friction coefficient and abrasion rate of glass fiber alone or glass fiber and potassium titanate fiber or plate-like potassium titanate as a base material in the following basic composition. It is the graph which showed the relationship in comparison.

[Blending composition] Phenol resin ("HP-309NS" manufactured by Hitachi Chemical Co., Ltd.): 25 parts Base material: (A) glass fiber ("FES-03-04" manufactured by Fuji Fiberglass Co., Ltd.) alone 30 parts (chopped strand having a fiber diameter of 13 μm and a length of 3 mm) (B) Glass fiber (“FE” manufactured by Fuji Fiberglass Co., Ltd.)
S-03-04 ") 15 parts (chopped strand having a fiber diameter of 13 μm and a length of 3 mm) Potassium titanate fiber (" Tismo D "manufactured by Otsuka Chemical Co., Ltd.) 15 parts (needle, diameter: 0.2 to 1.0) (μm, length: 5 to 20 μm) (C) Glass fiber (Fuji Fiberglass “FE”
S-03-04) 15 parts (chopped strand with a fiber diameter of 13 μm and a length of 3 mm) Plate-shaped potassium titanate (“TXAX-” manufactured by Kubota Corporation)
A ") 15 parts (plate shape, diameter: 10 to 30 m, length: 80 to 350 m)
m) Its multiple components: binder such as phenolic resin Friction modifier such as barium sulfate

As is clear from FIGS. 1 and 2, 300 ° C.
Comparing the coefficient of friction and the wear rate under high temperature conditions exceeding that of the above, it is found that those using plate-like potassium titanate can significantly improve the friction coefficient and wear rate at higher temperatures than those using potassium titanate fiber in combination. I understand.

The present invention has been completed based on such experimental results. The first feature is that glass fibers are used in combination with plate-like potassium titanate as a substrate for providing strength and wear characteristics. That is what exists. And, in order to effectively exhibit the combined effect of such plate-like potassium titanate, 1/1 with respect to the glass fiber blended as the base material.
It is necessary to use at least 3 volume ratio, and below this, the combined effect of plate-like potassium titanate cannot be effectively exhibited. The upper limit of the combined amount of plate-like potassium titanate is not particularly specified, but the combined effect is saturated at a mixing ratio of 1/1 by volume with respect to the glass fiber. Since it is uneconomical, considering the practicality, it is desired to suppress the volume ratio to 1/1 or less with respect to the glass fiber.

The glass fiber used as the substrate is
Similar to the conventional example, it is an indispensable component as an inexpensive material for providing the strength and friction characteristics as a friction material, and the condition that plate glass potassium titanate with a volume ratio of 1/1 or more with respect to the glass fiber is used in combination In order to exhibit the minimum effect as a base material under the above conditions, it is necessary to mix at least 15% by volume in the total amount of the friction material.

Accordingly, the total amount of glass fiber and plate-like potassium titanate in the total amount of the friction material is 20% by volume or more.
If the sum of these is too large, the friction material becomes brittle and the braking effect is reduced, and the function as the friction material is extremely reduced. Therefore, it is preferably 45% by volume or less, more preferably 40% by volume or less. It is desired to suppress.

Next, the thermosetting resin used as a binder is used as a matrix component of the friction material to provide flexibility, impact resistance,
A component for imparting braking performance, etc., which is preferable from the viewpoint of securing the strength characteristics under high temperature conditions, is exemplified as follows.
Phenolic resins, epoxy resins, melamine resins and the like. The blending amount of the thermosetting resin is not particularly limited. However, in order to effectively exhibit the function as a binder, it is preferably in the range of 10 to 30% by volume, more preferably 15 to 25% by volume based on the total amount of the friction material. When the amount of the binder is insufficient, the strength of the friction material is insufficient. On the other hand, when the amount is too large, a necessary porosity cannot be secured.

The essential constituents of the friction material according to the present invention are the above three components. If necessary, the performance can be further improved by further blending the following components.

[0016] First, organic fibers such as aramid fibers; inorganic fibers such as metal fibers such as carbon fiber, rock wool, copper, steel, and brass; Can be mentioned.

As a component for adjusting the friction characteristics and thermal conductivity at low to high temperatures or for imparting a cleaning effect to the organic film at the friction interface, for example, cashew dust, vulcanized or unvulcanized natural or synthetic vulcanizates Rubber powder, graphite, various sulfides (molybdenum disulfide, antimony trisulfide, etc.), metal oxides (MgO, Al ₂ O ₃ , ZrO ₂ , SiO ₂ , Sb ₂ O ₃ , Ti
O ₂ , Cu ₂ O ₃ , ZnO, Fe ₂ O ₃ , SnO ₂ , MoO ₃ , mullite, etc., chips or powders of various metals (iron, steel, Al, Zn, etc.), metal sulfates such as barium sulfate, An appropriate amount of a metal carbonate such as calcium carbonate and barium carbonate can be blended as desired as long as the above-mentioned features of the present invention are not impaired.

[0018]

EXAMPLES "FES-03-04" as glass fiber
(Manufactured by Fuji Fiber Glass Co., Ltd.), “TXAX-A” (manufactured by Kubota Corporation) as plate-like potassium titanate, “Tismo D” (manufactured by Otsuka Chemical Co., Ltd.) as needle-like potassium titanate fiber, binding Using "HP-309NS" (a phenolic resin manufactured by Hitachi Chemical Co., Ltd.) as an agent, a friction material having the composition shown in Table 1 was produced. The size of each fiber used is as described above.

[0019]

[Table 1]

For each of the obtained friction materials, JIS D-
When the relationship between the temperature and the coefficient of friction was examined in accordance with 4411, the results shown in FIG. As is apparent from this figure, in Experiments Nos. 1 to 3 satisfying the requirements of the present invention, all of the samples maintained a stable friction coefficient in a wide temperature range, and exhibited a high friction even in a high temperature range exceeding 300 ° C. The coefficient decreases little.

On the other hand, Comparative Example No. 4) containing only glass fiber and not blending plate-like potassium titanate, Comparative Example (No. 5) lacking in blending amount of plate-like potassium titanate, and plate-like titanium In Comparative Example (No. 6) in which needle-like potassium titanate fiber was used in place of potassium acid fiber, the coefficient of friction was significantly reduced in a high temperature range exceeding 300 ° C., and lacked suitability as a heat-resistant friction material. It turns out to be something.

FIGS. 4 and 5 show No. 1 in the above experimental example.
The mixing ratio of the plate-like potassium titanate or needle-like potassium titanate fiber to the glass fiber is changed in the range of 0 to 21 (volume ratio) in accordance with the compounding composition of No. 1 to No. 6, and the plate in the obtained friction material is changed. The compounding ratio of potassium titanate or needle-like potassium titanate fiber is abrasion rate or bending strength,
3 shows the results of examining the effect on strain at break.

As is clear from these figures, in all of the wear rate, bending strength, and strain at break, those using plate-like potassium titanate together with needle-like potassium titanate fibers are used. It has superior performance compared to
In particular, when the mixing ratio is 10% by volume or more, the difference becomes remarkable.

[0024]

The present invention is constituted as described above. In particular, by using a suitable amount of plate-like potassium titanate together with glass fiber as a reinforcing substrate, stable friction characteristics and strength can be obtained in a wide temperature range. A very good friction material can be provided.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a temperature and a friction coefficient when a type of a reinforcing base material is changed.

FIG. 2 is a graph showing the relationship between the temperature and the wear rate when the type of the reinforcing base material is changed.

FIG. 3 is a graph showing a relationship between a temperature of a friction material and a friction coefficient obtained in an example.

FIG. 4 is a graph showing the effect of the mixing ratio of plate-like potassium titanate or needle-like potassium titanate fibers on the wear rate at a high temperature.

FIG. 5 is a graph showing the effect of the mixing ratio of plate-like potassium titanate or needle-like potassium titanate fibers on bending strength and strain at break.

Claims (1)

(57) [Claims] 1. A friction material comprising a thermosetting resin as a binder and glass fibers mixed therein, wherein the thermosetting resin is:
10 to 30% by volume glass fiber and plate-like potassium titanate: containing 45 to 20% by volume in total, and the blending amount of the glass fiber is 15% by volume or more in the total amount of the friction material; A heat-resistant friction material comprising a plate-like potassium titanate having a volume ratio of 1/3 or more with respect to the fiber.