JP2016074812A - Friction material composition, and friction material and friction member using the friction material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction material composition not using asbestos, which does not contain antimony as an element, has an environmental harmfulness composition in which the content of copper is less than 0.5 mass% and low harmfulness to human body, shows stable friction coefficient in braking condition and in temperature and humidity, and gives a friction material having excellent abrasion resistance; and to provide a friction material and friction member using the friction material composition.SOLUTION: This invention relates to a friction material composition that comprises a binding agent, an organic filling material, an inorganic filling material, and a fiber substrate and does not comprise antimony as an element, where the friction material composition either does not comprise copper as an element or comprises less than 0.5 mass% of copper. The friction material component further comprises, as a titanate, potassium titanate and at least one of lithium potassium titanium oxide and magnesium potassium titanate, wherein the total amount of titanate is 8-30 mass%, the friction material component comprising 8-30 mass% of at least one of zirconium oxide and magnesium oxide.SELECTED DRAWING: None

Description

  The present invention relates to a friction material composition suitable for friction materials such as disc brake pads and brake linings used for braking of automobiles, etc., and a friction material and a friction member using the friction material composition.

  In automobiles and the like, friction materials such as disc brake pads and brake linings are used for braking. Friction materials such as a disc brake pad and a brake lining play a role of braking by friction with a disc rotor, a brake drum, or the like as a counterpart material. For this reason, friction materials not only require an appropriate coefficient of friction (effect characteristics) depending on the conditions of use, but also make brake noise less likely to occur (squeal characteristics) and have a longer life of friction material (wear resistance). Etc. are required.

  In particular, the stability of the coefficient of friction is an important factor that greatly affects not only the effectiveness characteristics but also the squeal characteristics. In general, if the friction coefficient is high, the probability of occurrence of brake squeal increases. Therefore, it is important to control the friction coefficient within an appropriate range regardless of environmental conditions such as braking conditions and temperature and humidity.

  Furthermore, in recent years, with the spread of regenerative coordination brakes, there is an increasing demand for the stability of the friction coefficient. Since the braking is electronically controlled in the regenerative cooperative brake, a braking force exceeding the driver's assumption that the friction coefficient of the friction material is not stable may be generated, resulting in a sudden braking. Conversely, the braking force required by the driver cannot be obtained and the braking distance may be extended, which may not only impair comfortable driving but also cause an accident.

  The friction material includes a binder, a fiber base material, an inorganic filler, an organic filler, and the like, and generally includes one or a combination of two or more of them in order to develop the above characteristics. . As the fiber base material, organic fiber, metal fiber, inorganic fiber or the like is used. Conventionally, asbestos has been used as textile equipment, but in recent years, non-asbestos friction materials that do not use asbestos have become mainstream.

  In a non-asbestos friction material that does not use asbestos, copper is an example of a material that has been used for the purpose of stabilizing the friction coefficient. Copper is a highly ductile metal that forms a coating by extending to the friction interface during braking, and moderately imparts adhesion and lubricity to the friction interface. As a result, not only the coefficient of friction is stabilized, but also the high temperature wear resistance is improved. However, the friction material containing copper or a copper alloy contains copper in the wear powder generated at the time of braking, and therefore it is suggested that the friction material may contaminate rivers and lakes.

  In addition, antimony compounds such as antimony trisulfide and antimony trioxide have been generally used as high-temperature lubricants different from copper, but it is desired not to add them to the friction material from the viewpoint of human harm.

  Several methods have been studied so far as alternative technologies for copper. For example, a method has been proposed in which copper is not used, magnesium oxide and graphite are contained in a friction material in an amount of 45 to 80% by volume, and the ratio of magnesium oxide and graphite is 1/1 to 4/1 (Patent Literature). 1).

JP 2002-138273 A

  In the brake friction material of Patent Document 1, the addition amounts of magnesium oxide as a grinding material and graphite as a lubricant are extremely increased, and it is difficult to improve various friction characteristics in a balanced manner. In particular, it is generally known that the lubricity of graphite is greatly affected by humidity, and the stability of the coefficient of friction against humidity is greatly impaired.

  Therefore, the present invention is a friction material that does not use asbestos, has a composition that does not contain antimony as an element and has a copper content not exceeding 0.5 mass%, and a low environmental hazard and a human hazard. It is an object of the present invention to provide a friction material composition that provides a friction material that exhibits a stable friction coefficient with respect to temperature and humidity and that has excellent wear resistance. Another object of the present invention is to provide a friction material and a friction member using the friction material composition.

  As a result of repeated studies by the inventors, the friction material composition does not contain antimony as an element and does not contain copper as an element, or the copper content does not exceed 0.5% by mass. In this case, the titanate contains potassium titanate and at least one of lithium potassium titanate and magnesium potassium titanate, and the total amount of the titanate is 8 to 30% by mass. In addition, by containing at least one of zirconium oxide and magnesium oxide in an amount of 8 to 30% by mass, a stable friction coefficient can be obtained even if the amount of copper added is extremely small, or contains no copper and does not contain antimony. It has been found that a friction material having excellent wear resistance can be provided.

  That is, the friction material composition of the present invention is a friction material composition containing a binder, an organic filler, an inorganic filler, and a fiber substrate, does not contain antimony as an element, and contains copper as an element. Does not contain, or the copper content does not exceed 0.5 mass%, contains titanate as potassium titanate, and contains at least one of lithium potassium titanate and magnesium potassium titanate, the titanium The total amount of the acid salt is 8 to 30% by mass, and at least one of zirconium oxide and magnesium oxide is contained in an amount of 8 to 30% by mass.

  The friction material composition preferably contains magnesium potassium titanate. Moreover, in the said friction material composition, it is preferable to contain 4-20 mass% of magnesium potassium titanates, and / or it is preferable to contain 8-20 mass% of zirconium oxide. Further, the friction material composition is preferably formed into a friction material, and the friction material and the back metal are preferably integrated into a friction member.

  According to the present invention, when used in a friction material such as an automotive disc brake pad or brake lining, the composition has a low environmental hazard and a low human hazard, and has a stable friction coefficient and excellent wear resistance. The friction material composition which provides the friction material which has can be provided. Moreover, according to this invention, the friction material and friction member which have the said characteristic can be provided.

  Hereinafter, the friction material composition of the present invention, the friction material using the same, and the friction member will be described in detail. The friction material composition of the present invention is a so-called non-asbestos friction material composition that does not contain asbestos.

[Friction material composition]
The friction material composition of this embodiment is a friction material composition containing a binder, an organic filler, an inorganic filler, and a fiber base material, does not contain antimony as an element, and contains copper as an element. Or the content of copper does not exceed 0.5% by mass, and contains titanate as potassium titanate and at least one of lithium potassium titanate and magnesium potassium titanate, and the titanate The total amount of the salt is 8 to 30% by mass, and 8 to 30% by mass of at least one of zirconium oxide and magnesium oxide is contained. In addition, said "antimony as an element" shows the content rate in the total friction material composition of the antimony element contained in the antimony compound represented by antimony trisulfide and antimony trioxide. Moreover, "copper as an element" shows the content rate in the total friction material composition of the copper element contained in copper, copper alloy, and a copper compound, such as fibrous form and a powder form.

[Inorganic filler]
The friction material composition of this embodiment contains an inorganic filler. The inorganic filler is included as a friction modifier in order to avoid deterioration of the heat resistance of the friction material. In the present embodiment, the inorganic filler contains potassium titanate as a titanate, and at least one of magnesium potassium titanate and lithium potassium titanate. Furthermore, it contains at least one of zirconium oxide and magnesium oxide.

  The total content of the titanate is preferably 8 to 30% by mass, more preferably 8 to 25% by mass, and further preferably 10 to 25% by mass. By setting the content of titanate to 8% by mass or more, the stability of the friction coefficient is improved, and by setting it to 30% by mass or less, an extreme increase in porosity can be avoided. If the porosity is extremely increased, not only the mechanical strength of the friction material is reduced, but also the stability of the friction coefficient is reduced due to moisture absorption, and the risk that the friction material and the counterpart are fixed by rust increases. As potassium titanate, potassium potassium titanate, potassium titanate 6 or the like can be used.

  Further, even if only potassium titanate is contained, excellent wear resistance cannot be obtained. On the other hand, if only at least one of magnesium potassium titanate and lithium potassium titanate is contained, the friction coefficient is extremely lowered. Therefore, it is necessary to contain not only potassium titanate but also at least one of magnesium potassium titanate and lithium potassium titanate in combination.

  Furthermore, it is more preferable to contain potassium magnesium titanate. Magnesium potassium titanate has a higher melting point than lithium potassium titanate, and the wear resistance of the friction material in a high temperature region is further improved.

  Furthermore, the content of magnesium potassium titanate is preferably 2 to 20% by mass, more preferably 2 to 16% by mass, and even more preferably 2 to 12% by mass. By setting the content of magnesium potassium titanate to 2% by mass or more, the wear resistance of the friction material is improved, and by setting it to 20% by mass or less, an extreme decrease in the friction coefficient can be avoided.

  The content of zirconium oxide and magnesium oxide is preferably 8 to 30% by mass, more preferably 8 to 25% by mass, and further preferably 10 to 25% by mass. When the content of zirconium oxide and magnesium oxide is 8% by mass or more, an extreme decrease in the friction coefficient can be avoided, and when the content is 30% by mass or less, the wear resistance of the friction material is extremely deteriorated. It is possible to avoid an extremely high attack on the opponent material.

  The median diameter of the zirconium oxide and magnesium oxide is preferably 1 to 30 μm, more preferably 1 to 20 μm, and further preferably 1 to 15 μm. By setting the median diameter of zirconium oxide and magnesium oxide to 1 μm or more, good friction coefficient and wear resistance are exhibited, and by setting the median diameter to 30 μm or less, the dispersibility at the friction interface can be improved and the friction coefficient can be stabilized. Therefore, it is possible to avoid an extremely high aggressiveness to the opponent material.

  The median diameter of the zirconium oxide and magnesium oxide can be measured using a method such as laser diffraction particle size distribution measurement. For example, it can be measured with a laser diffraction / scattering particle size distribution measuring device, trade name: LA.920 (manufactured by Horiba, Ltd.). Moreover, if it is a grade which does not impair the effect of this invention, the inorganic filler normally used for a friction material can be used in combination with the zirconium oxide of this embodiment, and magnesium oxide.

  Examples of inorganic fillers other than zirconium oxide and magnesium oxide include, for example, tin sulfide, molybdenum disulfide, iron sulfide, bismuth sulfide, zinc sulfide, calcium hydroxide, calcium oxide, sodium carbonate, calcium carbonate, magnesium carbonate, and sulfuric acid. Activated alumina such as barium, dolomite, coke, graphite, mica, iron oxide, vermiculite, calcium sulfate, talc, clay, zeolite, zirconium silicate, mullite, chromite, titanium oxide, silica, and γ-alumina can be used. Can be used alone or in combination of two or more.

  The total content of the inorganic filler is preferably 20 to 80% by mass, more preferably 30 to 80% by mass in the friction material composition, including zirconium oxide and magnesium oxide. More preferably, it is mass%. When content of an inorganic filler shall be 20-80 mass%, a heat resistant deterioration can be avoided.

[Fiber base]
The friction material composition of this embodiment contains a fiber base material. The fiber base material exhibits a reinforcing action in the friction material. Examples of the fiber base material include organic fibers, metal fibers, and inorganic fibers.

  The friction material composition of this embodiment can use an aramid fiber, an acrylic fiber, a cellulose fiber, a phenol resin fiber, etc. as an organic fiber, and these can be used individually or in combination of 2 or more types. Among these, it is preferable to use an aramid fiber from the viewpoint of heat resistance and a reinforcing effect.

  As the metal fiber, copper fiber, iron-based fiber, titanium fiber, zinc fiber, aluminum fiber, etc. can be used, and one kind or a combination of two or more kinds can be used. The copper content as an element in the inside should not exceed 0.5 mass%.

  As the inorganic fiber, wollastonite, ceramic fiber, biodegradable ceramic fiber, mineral fiber, carbon fiber, glass fiber, potassium titanate fiber, aluminosilicate fiber, etc. can be used, one or a combination of two or more types However, from the viewpoint of environmental friendliness, it is preferable not to contain attractive potassium titanate fibers.

The mineral fiber referred to here is a man-made inorganic fiber melt-spun mainly composed of blast furnace slag such as slag wool, basalt such as basalt fiber, and other natural rocks, and is a natural mineral containing Al element. Is more preferable. Specifically, those containing SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O, etc., or those containing one or more of these compounds can be used as mineral fibers. Of these, those containing an Al element are more preferred. Since the adhesive strength with each component in the friction composition tends to decrease as the average fiber length of the entire mineral fiber contained in the friction material composition increases, the average fiber length of the entire mineral fiber is preferably 500 μm or less, More preferably, it is 100-400 micrometers. Here, the average fiber length refers to a number average fiber length indicating an average value of the lengths of all corresponding fibers. For example, the average fiber length of 200 μm indicates that 50 mineral fibers used as a friction material composition raw material are randomly selected, the fiber length is measured with an optical microscope, and the average value is 200 μm.

The mineral fiber used in the present embodiment is preferably biosoluble from the viewpoint of human harm. The term “biosoluble mineral fiber” as used herein refers to a mineral fiber having a characteristic that even if it is taken into the human body, it is partially decomposed and discharged outside the body in a short time. Specifically, the chemical composition is alkali oxide, alkaline earth oxide total amount (total amount of oxides of sodium, potassium, calcium, magnesium, barium) is 18% by mass or more, and in a short-term biopermanent test by respiration, A fiber that has a mass half-life of 20 μm or more within 40 days or no evidence of excessive carcinogenicity in an intraperitoneal test or that has no associated pathogenicity or tumor development in a long-term respiratory test (EU Directive 97 / 69 / EC Nota Q (carcinogenic exclusion)). Examples of such biodegradable mineral fibers include SiO ₂ —Al ₂ O ₃ —CaO—MgO—FeO—Na ₂ O fibers and the like, and include SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na. Examples thereof include fibers containing ₂ O or the like in any combination. As a commercial item, LAPINUS FIBERS B.M. V. Roxul series ("Roxul" is a registered trademark) manufactured by the company, and the like. “Roxul” includes SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O and the like.

  The fiber base material is preferably contained in the friction material composition in an amount of 5 to 40% by mass, more preferably 5 to 35% by mass, and further preferably 6 to 30% by mass. When the content of the fiber base is 5 to 40% by mass, there is an effect of imparting an appropriate reinforcing effect to the friction material without causing adverse effects such as a significant decrease in effectiveness characteristics.

[Binder]
The friction material composition of this embodiment contains a binder. The binding material provides strength by integrating the organic filler and the fiber base material included in the friction material composition. As the binder contained in the friction material composition of the present embodiment, a thermosetting resin usually used for a friction material can be used. Examples of the thermosetting resin include various modified phenol resins such as phenol resin, acrylic modified phenol resin, silicone modified phenol resin, cashew modified phenol resin, epoxy modified phenol resin, and alkylbenzene modified phenol resin. Acrylic-modified phenolic resins and silicone-modified phenolic resins are preferred, and these can be used alone or in combination of two or more. In order to give good heat resistance, moldability and friction coefficient, it is preferable to use a phenol resin, an acrylic modified phenol resin, a silicone modified phenol resin, or an alkylbenzene modified phenol resin.

  In the friction material composition of the present embodiment, the content of the binder is preferably 5 to 20% by mass, more preferably 5 to 15% by mass, and further preferably 5 to 10% by mass. preferable. By setting the content of the binder in the range of 5 to 20% by mass, it is possible to further suppress the strength reduction of the friction material, reduce the porosity of the friction material, and increase the elastic modulus. Vibration performance deterioration can be suppressed.

[Organic filler]
The friction material composition of this embodiment contains an organic filler. The organic filler is included as a friction modifier for improving the sound vibration performance and wear resistance of the friction material. As an organic filler contained in the composition for a friction material of the present invention, cashew dust, a rubber component, or the like can be used.

  The cashew dust is not particularly limited as long as it is obtained by pulverizing a cashew nut shell oil that has been polymerized and cured, and is usually used for a friction material.

  Examples of the rubber component include tire rubber, acrylic rubber, isoprene rubber, NBR (nitrile butadiene rubber), and SBR (styrene butadiene rubber), and these are used alone or in combination of two or more.

  In addition, cashew dust and a rubber component may be used in combination, or cashew dust coated with a rubber component may be used, but from the viewpoint of sound vibration performance, it is preferable to use cashew dust and a rubber component in combination. . The cashew dust content is preferably 2 to 8% by mass, more preferably 2.5 to 8% by mass, and even more preferably 2.5 to 7.5% by mass. By setting the cashew dust content to 2 to 8% by mass, it is possible to avoid deterioration of sound vibration performance such as squeal due to an increase in the elastic modulus of the friction material, deterioration of heat resistance, and strength due to thermal history. Degradation can be avoided.

  The content of the organic filler in the friction material composition of the present embodiment is preferably 1 to 20% by mass, more preferably 1 to 15% by mass, and 2 to 10% by mass. Is more preferable. By setting the content of the organic filler in the range of 1 to 20% by mass, it is possible to avoid deterioration of sound vibration performance such as squeal due to an increase in the elastic modulus of the friction material, deterioration of heat resistance, heat It is possible to avoid a decrease in strength due to history.

[Other ingredients]
Moreover, the friction material composition of this embodiment can mix | blend other materials as needed other than the said material, for example, metal powders, such as iron powder and zinc powder, etc. can be mix | blended. .

<Friction material and friction member>
The friction material composition of the present embodiment is used as a friction material for disc brake pads, brake linings, etc. of automobiles or by subjecting the friction material composition of the present embodiment to a desired shape, processing, pasting, and the like. It can also be used as a friction material for clutch facings, electromagnetic brakes, holding brakes and the like.

The friction material composition of the present embodiment can be used as a friction member itself that becomes a friction surface to obtain a friction material. Examples of the friction material using the same include the following configurations.
(1) Configuration of only friction member (2) Configuration having a back metal and a friction member formed on the back metal and made of the friction material composition of the present invention to be a friction surface (3) Configuration of (2) above In the structure, a primer layer for the purpose of surface modification for enhancing the adhesion effect of the back metal between the back metal and the friction member, a configuration in which an adhesive layer for the purpose of bonding the back metal and the friction member is further interposed, etc. Can be mentioned.

  The backing metal is usually used as a friction member in order to improve the mechanical strength of the friction member. As the material, metal or fiber reinforced plastic can be used, for example, iron, stainless steel, inorganic fiber, etc. Examples include reinforced plastic and carbon fiber reinforced plastic. The primer layer and the adhesive layer may be those used for friction members such as brake shoes.

  The friction material composition of this embodiment can manufacture a friction material using the method generally used, and can manufacture it by heat-press-molding the friction material composition of this invention. In detail, for example, the friction material composition of the present embodiment is mixed with a Laedige mixer (“Laedige” is a registered trademark), a pressure kneader, an Eirich mixer (“Eirich” is a registered trademark), or the like. The mixture is uniformly mixed using a machine, this mixture is preformed in a molding die, and the resulting preform is molded under conditions of a molding temperature of 130 to 160 ° C., a molding pressure of 20 to 50 MPa, and a molding time of 2 to 10 minutes. The friction material of this embodiment can be obtained by molding and heat-treating the resulting molded product at 150 to 250 ° C. for 2 to 10 hours. In addition, you may perform a coating, a scorch process, a grinding | polishing process, etc. as needed.

  The friction material composition of the present embodiment is excellent in stability of the coefficient of friction, wear resistance at high temperature, and the like, and thus is useful as a “upholstery material” for friction members such as disc brake pads and brake linings. It can also be molded and used as a “underlaying material” for the member.

  The “upper material” is a friction material that becomes the friction surface of the friction member, and the “underlay material” is a friction material that is interposed between the friction material that becomes the friction surface of the friction member and the back metal. It is a layer for the purpose of improving the shear strength and crack resistance in the vicinity of the adhesion part with the back metal.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these.

<Examples 1-7 and Comparative Examples 1-7>
[Production of disc brake pads]
The materials were blended according to the blending ratios shown in Tables 1 and 2, and the friction material compositions of Examples 1 to 7 and Comparative Examples 1 to 7 were obtained.

This friction material composition was mixed with a Laedige mixer (manufactured by Matsubo Co., Ltd., trade name: Ladige mixer M20), and this mixture was preformed with a molding press (manufactured by Oji Machinery Co., Ltd.), and obtained. The preform is heated and pressure-molded with a backing metal (manufactured by Hitachi Automotive Systems) using a molding press (manufactured by Sanki Seiko Co., Ltd.) under conditions of a molding temperature of 145 ° C., a molding pressure of 35 MPa, and a molding time of 5 minutes. The molded product thus obtained was heat-treated at 200 ° C. for 4.5 hours, polished using a rotary polishing machine, subjected to scorch treatment at 500 ° C., and a disc brake pad (friction material thickness 9.5 mm, friction A material projection area of 52 cm ² was obtained.

The various materials used in the examples and comparative examples are as follows.
[Binder]
・ Phenolic resin: manufactured by Hitachi Chemical Co., Ltd. (trade name: HP491UP)
[Organic filler]
・ Cashew dust ・ SBR powder
[Inorganic filler]
・ Titanate A
8 Potassium titanate: manufactured by Otsuka Chemical Co., Ltd. (trade name: Terrases TF-SS)
・ Titanate B
6 Potassium titanate: manufactured by Toho Material Co., Ltd. (trade name TOFIX-S)
・ Titanate C
Magnesium potassium titanate: Otsuka Chemical Co., Ltd. (trade name Terraces PCS)
・ Titanate D
Lithium potassium titanate: manufactured by Otsuka Chemical Co., Ltd. (trade name Terraces L-SS)
Barium sulfate, graphite, tin sulfide, mica, calcium hydroxide, zirconium oxide: manufactured by Daiichi Rare Element Chemical Industries, Ltd. (trade name BR-QZ)
Magnesium oxide: manufactured by Kyowa Chemical Industry Co., Ltd. (trade name: Industrial magnesium oxide 2000)
[Fiber base]
・ Aramid fiber (organic fiber)
・ Mineral fiber (inorganic fiber)

  Various performances of the disc brake pads of Examples 1 to 7 and Comparative Examples 1 to 7 produced by the above-described method were evaluated using a brake dynamo tester (manufactured by Nippon Steel Corporation). In the experiment, a general pin-slide collet caliper and a ventilated disc rotor (FC250 (gray cast iron)) manufactured by Kiriu Co., Ltd. were used. Went.

[Evaluation of efficacy characteristics]
The test was based on the Japan Society of Automotive Engineers standard JASO C406, and the friction coefficient of 50 km / h-0.3G and 130 km / h-0.3G sections in the second efficacy test was evaluated. However, the evaluation was performed at a temperature of 35 ° C. and a humidity of 60% assuming a summer environment, and at a temperature of 0 ° C. and a humidity of 35% assuming a winter environment.

(Coefficient of friction)
In both the summer environment and the winter environment, the friction coefficients of the 50 km / h-0.3G and 130 km / h-0.3G sections in the second efficacy test were evaluated.
A: 0.38 to 0.42
○: 0.36 to 0.37, 0.43 to 0.45
Δ: 0.34 to 0.35, 0.46 to 0.47
X: Less than 0.34, 0.48 or more

(Effective stability against speed)
As the stability against speed, the difference between the friction coefficient of 130 km / h-0.3 G section and the friction coefficient of 50 km / h-0.3 G section in winter environment was evaluated.
A: 0.02 or less B: 0.03
Δ: 0.04
X: 0.05 or more

(Effective and stable for the environment)
As the stability to the environment, the difference in the friction coefficient of 50 km / h-0.3 G section in the winter environment and the summer environment was evaluated.
A: 0.02 or less B: 0.03
Δ: 0.04
X: 0.05 or more

[Evaluation of wear resistance]
The test was based on JASO C427, and the amount of wear of the disk pad when the brake temperature before braking was 400 ° C. was measured and evaluated as wear resistance.
A: Less than 0.60 mm B: 0.60 to 0.89 mm
Δ: 0.90 to 1.19 mm
×: 1.20mm or more

  Examples 1 to 7 showed the same level of friction coefficient stability and wear resistance as those of Comparative Example 7 containing copper and antimony trisulfide. Moreover, Examples 1-7 are the comparative examples 1 and 2 which contain only potassium titanate, the comparative examples 3 and 4 which contain only magnesium titanate, the comparative example 5 in which the total rate of a titanate exceeds 30 mass%, oxidation It is clear that the stability of the friction coefficient and the wear resistance are superior to Comparative Example 6 in which the zirconium content exceeds 30% by mass.

The friction material composition of the present invention, compared with the conventional product, is stable in friction coefficient against external disturbances such as braking conditions and the environment, and wear resistance without using copper and antimony compounds, which are environmentally hazardous and highly harmful to the human body. Due to its excellent properties, the friction material composition is suitable for friction materials and friction members such as brake pads for passenger cars.

Claims (6)

A friction material composition comprising a binder, an organic filler, an inorganic filler, and a fiber substrate;
Does not contain antimony as an element, does not contain copper as an element, or the copper content does not exceed 0.5% by mass,
As titanate, it contains potassium titanate, and contains at least one of lithium potassium titanate and magnesium potassium titanate,
A friction material composition, wherein a total amount of the titanate is 8 to 30% by mass, and at least one of zirconium oxide and magnesium oxide is contained in an amount of 8 to 30% by mass.   The friction material composition according to claim 1, comprising magnesium potassium titanate.   The friction material composition according to claim 2, containing 2 to 20% by mass of magnesium potassium titanate.   The friction material composition according to claim 1, containing 8 to 20 mass% of zirconium oxide.   The friction material formed by shape | molding the friction material composition as described in any one of Claims 1-4. A friction member obtained by integrating the friction material according to claim 5 and a back metal.