JP7020506B2 - Friction materials and friction members - Google Patents

Description

The present invention relates to a non-asbestos friction material composition, a friction material using the non-asbestos friction material composition, and a friction member. Specifically, it is suitable for friction materials such as disc brake pads and brake linings used for braking automobiles, etc., is environmentally friendly due to its low copper content, has excellent wear resistance at high temperatures, and produces metal catches. The present invention relates to a small amount of non-asbestos friction material composition, and further to a friction material and a friction member using the non-asbestos friction material composition.

Friction materials such as disc brake pads and brake linings are used for braking in automobiles and the like. The friction material plays a role of braking by rubbing against a facing material such as a disc rotor and a brake drum. Therefore, the friction material is required not only to have a high coefficient of friction and stability of the coefficient of friction, but also to have a long pad life (wear resistance) in a wide brake operating temperature range from low temperature to high temperature.

Further, in a high temperature range where the brake is used, a lump of metal wear powder called a metal catch may be generated on the surface of the friction material, an increase in the amount of wear of the disc rotor and the friction material, and a squeal of the brake may occur. Therefore, it has been proposed to add a metal sulfide in order to improve the wear resistance at high temperature and suppress the metal catch (see Patent Document 1).

On the other hand, the friction material includes a binder, a fiber base material, an inorganic filler, an organic filler, and the like, and generally, one or a combination of two or more thereof is used in order to exhibit the above-mentioned characteristics. included. Organic fibers, metal fibers, inorganic fibers and the like are used as the fiber base material, and copper and copper alloy fibers are used as the metal fibers in order to improve wear resistance. Further, as the friction material, non-asbestos friction material is the mainstream, and copper, copper alloy and the like are used in a large amount in this non-asbestos friction material.

However, friction materials containing copper or copper alloys contain copper in the wear debris generated during braking, and it has been suggested that they may cause pollution of rivers, lakes, oceans, etc., so there is a movement to limit their use. It is increasing. Therefore, a method is proposed in which magnesium oxide and graphite are contained in the friction material in an amount of 45 to 80% by volume without containing a metal such as copper or a copper alloy, and the ratio of magnesium oxide to graphite is 1/1 to 4/1. (See Patent Document 2).

Japanese Patent Application Laid-Open No. 2003-313312 Japanese Unexamined Patent Publication No. 2002-138273

However, it has been difficult to achieve both wear resistance at high temperatures and suppression of metal catch with the friction materials that have been developed so far and have a low content of copper and copper alloys.

Therefore, the present invention provides a non-asbestos friction material composition capable of providing a friction material having excellent wear resistance at high temperatures and producing less metal catch even if the content of copper and the copper alloy is small. It is an object of the present invention to provide a friction material and a friction member using a non-asbestos friction material composition.

As a result of diligent studies, the present inventors have made the content of copper as an element below a certain level, the content of metal fibers other than copper and copper alloys below a certain level, and titanium in the non-asbestos friction material composition. The present invention has been completed by finding that the above problems can be solved by containing a specific amount of the acid salt and further containing zirconium oxide having a specific particle size.
That is, the present invention is as follows.

[1] A friction material composition containing a binder, an organic filler, an inorganic filler and a fiber base material.
The content of copper in the friction material composition is 5% by mass or less as a copper element, the content of metal fibers other than copper and copper alloy is 0.5% by mass or less, and the content of organic filler is The content is 1 to 20% by mass, the content of titanate is 13 to 24% by mass, the content of zirconium oxide is 5 to 30% by mass, and the content of zirconium oxide having a particle size of more than 30 μm is 1.0. A non-asbestos friction material composition having a mass% or less.
[2] The non-asbestos friction material composition according to the above [1], wherein the fiber base material is at least one selected from the group consisting of inorganic fibers, metal fibers, organic fibers and carbon-based fibers.
[3] The non-asbestos friction material composition according to the above [1] or [2], wherein the content of the fiber base material is 5 to 40% by mass.
[4] A friction material obtained by molding the non-asbestos friction material composition according to any one of the above [1] to [3].
[5] A friction member formed by using a friction material obtained by molding the non-asbestos friction material composition according to any one of the above [1] to [3] and a back metal.

The non-asbestos friction material composition of the present invention is environmentally friendly and resistant to high temperatures because the amount of copper in the wear powder generated during braking is small when used as a friction material for automobile disc brake pads and brake linings. It has excellent wear resistance and can suppress metal catch. Further, by using the non-asbestos friction material composition of the present invention, it is possible to provide a friction material and a friction member having the above-mentioned characteristics.

Hereinafter, the non-asbestos friction material composition of the present invention, and the friction material and the friction member using the non-asbestos friction material composition will be described in detail.
[Non-asbestos friction material composition]
The non-asbestos friction material composition of the present invention is a friction material composition containing a binder, an organic filler, an inorganic filler and a fiber base material, and the content of copper in the friction material composition is a copper element. It contains 5% by mass or less, the content of metal fibers other than copper and copper alloy is 0.5% by mass or less, contains titanate and zirconium oxide having a particle size of 30 μm or less, and the titanate. The content of the copper is 10 to 35% by mass, and the content is substantially free of copper oxide having a particle size of more than 30 μm.
With the above configuration, since less copper is generated in the wear debris during braking as compared with the conventional product, it is environmentally friendly, has excellent wear resistance at high temperatures, and can exhibit the effect of suppressing metal catch. ..

(Binding material)
The binder integrates the organic filler, the inorganic filler, the fiber base material, and the like contained in the friction material composition to give strength. The binder contained in the non-asbestos friction material composition of the present invention is not particularly limited, and a thermosetting resin usually used as a binder for the friction material can be used.
Examples of the heat-curable resin include phenolic resins; various elastomer-dispersed phenolic resins such as acrylic elastomer-dispersed phenolic resins and silicone elastomer-dispersed phenolic resins; acrylic-modified phenolic resins, silicone-modified phenolic resins, cashew-modified phenolic resins, and epoxy-modified phenolic resins. Examples thereof include various modified phenolic resins such as resins and alkylbenzene-modified phenolic resins, and these can be used alone or in combination of two or more. In particular, it is preferable to use a phenol resin, an acrylic-modified phenol resin, a silicone-modified phenol resin, or an alkylbenzene-modified phenol resin because it gives good heat resistance, moldability, and a coefficient of friction.

The content of the binder in the non-asbestos friction material composition of the present invention is preferably 5 to 20% by mass, more preferably 5 to 10% by mass. By setting the content of the binder in the range of 5 to 20% by mass, it is possible to further suppress the decrease in the strength of the friction material, and the porosity of the friction material is reduced and the elastic modulus is increased, resulting in noise such as squealing. Deterioration of vibration performance can be suppressed.

(Organic filler)
The organic filler is contained as a friction modifier for improving the sound vibration performance and wear resistance of the friction material. The organic filler contained in the non-asbestos friction material composition of the present invention is not particularly limited as long as it can exhibit the above performance, and cashew dust, a rubber component, or the like, which is usually used as an organic filler, is used. Can be done.
The cashew dust may be any material that is usually used as a friction material and is obtained by crushing a hardened cashew nut shell oil.
Examples of the rubber component include tire rubber, acrylic rubber, isoprene rubber, NBR (nitrile butadiene rubber), SBR (styrene butadiene rubber) and the like, and these are used alone or in combination of two or more.
Further, 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 content of the organic filler in the non-asbestos friction material composition of the present invention is preferably 1 to 20% by mass, more preferably 1 to 10% by mass, and 3 to 8% by mass. Is even more preferable. By setting the content of the organic filler in the range of 1 to 20% by mass, the elastic modulus of the friction material becomes high, deterioration of sound vibration performance such as squeal can be avoided, and deterioration of heat resistance and heat can be avoided. It is possible to avoid a decrease in strength due to history. When cashew dust and a rubber component are used in combination, the cashew dust and the rubber component are preferably in a mass ratio of 2: 1 to 10: 1, preferably 3: 1 to 9: 1. More preferably, it is 3: 1 to 8: 1.

(Inorganic filler)
The inorganic filler is contained as a friction modifier for avoiding deterioration of the heat resistance of the friction material, and in the present invention, titanate and zirconium oxide are essential as the inorganic filler.
As the titanate, potassium titanate, lithium lithium titanate, magnesium potassium titanate and the like can be used. Examples of potassium titanate include K2O · _{6TIO 2} , K2O · _{8TIO 2} , and the like. Examples of the lithium titanate include those having a composition represented by K _0.3-0.7 Li _0.27 Ti _1.73 O _3.8-3.95 produced by mixing a titanium source, a lithium source, and a potassium source. Examples of the magnesium potassium titanate include those having a composition represented by K _0.2-0.7 Mg _0.4 Ti _1.6 O _3.7-3.95 produced by mixing a titanium source, a magnesium source, and a potassium source.
These can be used alone or in combination of two or more. Of these, lithium potassium titanate and potassium magnesium titanate are preferable because they further improve wear resistance at high temperatures.

As the shape of the titanate, fibrous, columnar, plate-like, particulate or scaly ones can be used, and these can be used alone or in combination of two or more.
The shape of the titanate can be analyzed, for example, by observation with a scanning electron microscope (SEM).
Here, an example of the definition of the shape of titanate will be described. The longest side of the rectangular parallelepiped having the smallest volume among the rectangular parallelepipeds circumscribing the titanate (extrinsic rectangular parallelepiped) is the major axis L, the next longest side is the minor axis B, and the shortest side is the thickness T (B> T). ), The shape of the titanate is defined by the aspect ratio (L / T, L / B).
The fibrous titanate is a titanate having an L / T greater than 10 and an L / B greater than 10. For example, Tismo D, Tismo N (both manufactured by Otsuka Chemical Co., Ltd.) and the like can be mentioned.
The columnar titanium salt is a titanium salt having L / T = 2 to 10 and L / B = 2 to 10. TOFIX-S (manufactured by Toho Material Co., Ltd.) and the like can be mentioned.
The plate-shaped titanate is a titanate having an L / T of more than 10 and an L / B of less than 10. For example, TXAX-A, TXAX-MA, TXAX-KA, TXAX-CT (all manufactured by Kubota Co., Ltd.) and the like can be mentioned.

The particulate titanate is a titanate having an L / T of less than 10 and an L / B of less than 2. For example, TOFIX-SGL (manufactured by Toho Material Co., Ltd.), GTX-C (manufactured by Kubota Co., Ltd.) and the like can be mentioned.
Further, among the particulate titanium salts, those having a thin plate shape such as scales are called scaly titanates, for example, Terrases PS, Terrases PM, Terrases L, Terrases TF-S (all of them). Otsuka Chemical Co., Ltd.) and the like.
Among the above shapes, it is preferable to use a flaky, columnar or plate shape in order to further improve high temperature wear resistance.
Further, those having an average particle diameter of 1 to 50 μm and a specific surface area of 0.5 to 10 m ² / g are preferable. The average particle diameter is represented by the median diameter, and the median diameter indicates a 50% diameter obtained from the volume distribution of the laser diffraction method. Further, the specific surface area can be obtained by a BET method or the like using nitrogen gas as an adsorbed gas.

The content of titanium acid in the non-asbestos friction material composition of the present invention is 10 to 35% by mass, and 13 to 24% by mass from the viewpoint of improving wear resistance at high temperatures and suppressing metal catch. It is preferably present, and more preferably 14 to 20% by mass. When the content of the titanate is less than 10% by mass, the wear resistance is deteriorated and the metal catch tends to be easily formed. Further, when the content exceeds 35% by mass, the wear resistance is deteriorated, the friction coefficient is lowered, and the metal catch tends to be easily generated.

The composition for non-asbestos friction material of the present invention contains zirconium oxide having a particle size of 30 μm or less (hereinafter, may be simply referred to as zirconium oxide) as an inorganic filler as an essential component, and has a particle size of more than 30 μm. It contains substantially no zirconium oxide. It is preferable that the particle size of zirconium oxide is 28 μm or less and substantially does not contain zirconium oxide having a particle size of more than 28 μm, and more preferably the particle size of zirconium oxide is 25 μm or less and the particle size is 25 μm. It is substantially free of excess zirconium oxide.
By using zirconium oxide having a particle size of 30 μm or less, good high-temperature wear resistance can be exhibited and metal catch can be suppressed. The minimum particle size of zirconium oxide having a particle size of 30 μm or less is not particularly limited, but the particle size is preferably 0.1 μm or more.

Here, "substantially free" means, for example, that when zirconium oxide having a particle size of more than 30 μm is not substantially contained, the particle size of the zirconium oxide contained in the friction material composition of the present invention is It means that the ratio of zirconium oxide exceeding 30 μm is 1.0% by mass or less, more preferably 0.5% by mass or less, and further not containing zirconium oxide particles exceeding 30 μm (0% by mass). preferable.

The content of zirconium oxide is preferably 2 to 41% by mass, more preferably 1 to 40% by mass. By setting the content of zirconium oxide to 2 to 41% by mass, preferably 1 to 40% by mass, excellent wear resistance can be exhibited and metal catch can be suppressed. Further, in order to further exhibit these effects, it is more preferably 5 to 30% by mass, and particularly preferably 5 to 20% by mass.

The average particle size of zirconium oxide is preferably 1 to 7 μm, more preferably 1 to 6.5 μm, and even more preferably 1 to 6 μm. When the average particle size of zirconium oxide is 1 μm or more, a good friction coefficient and wear resistance are exhibited, and when it is 7 μm or less, deterioration of wear resistance can be avoided.
The particle size and average particle size of zirconium oxide can be measured by using a method such as laser diffraction particle size distribution measurement. For example, it can be measured with a laser diffraction / scattering type particle size distribution measuring device LA 920 (manufactured by HORIBA, Ltd.). The average particle size means a 50% diameter obtained from the volume distribution of the particle size distribution.

The non-asbestos friction material composition of the present invention can further contain an inorganic filler other than the above-mentioned titanate and zirconium oxide. The inorganic filler that can be contained is not particularly limited as long as it is usually used for a friction material.
Examples of the inorganic filler include tin sulfide, molybdenum disulfide, iron sulfide, antimony trisulfide, bismuth sulfide, zinc sulfide, calcium hydroxide, calcium oxide, sodium carbonate, calcium carbonate, magnesium carbonate, barium sulfate, and dolomite. Active alumina such as coke, graphite, mica, iron oxide, vermiculite, calcium sulfate, talc, clay, zeolite, zirconium silicate, zirconium oxide, sulfur, chromite, titanium oxide, magnesium oxide, silica, iron oxide, γ-alumina, etc. Can be used, and these can be used alone or in combination of two or more. Among these, graphite and barium sulfate are preferably contained from the viewpoint of reducing the aggression to the facing material, and antimony trisulfide is preferably contained from the viewpoint of improving the friction coefficient.

The content of the inorganic filler in the non-asbestos friction material composition of the present invention is preferably 30 to 80% by mass, more preferably 40 to 80% by mass, and more preferably 60 to 80% by mass. More preferred. By setting the content of the inorganic filler in the range of 30 to 80% by mass, deterioration of heat resistance can be avoided. The content of the inorganic filler includes the content of the titanium salt and zirconium oxide having a specific particle size.

(Fiber base material)
The fiber base material exhibits a reinforcing action in the friction material.
As the fiber base material contained in the non-asbestos friction material composition of the present invention, inorganic fibers, metal fibers, organic fibers, carbon-based fibers and the like, which are usually used as fiber base materials, can be used, and these can be used alone. Alternatively, two or more types can be used in combination. The fiber base material referred to here does not include the above-mentioned fibrous titanate.

As the inorganic fiber, ceramic fiber, biodegradable ceramic fiber, mineral fiber, glass fiber, silicate fiber and the like can be used, and one kind or a combination of two or more kinds can be used.
The mineral fiber referred to here is an artificial inorganic fiber melt-spun mainly containing 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, more preferably. Of these, those containing Al element can be used as mineral fibers. As the average fiber length of the entire mineral fiber contained in the friction material composition increases, the adhesive strength with each component in the friction composition tends to decrease. Therefore, the average fiber length of the entire mineral fiber is preferably 500 μm or less. More preferably, it is 100 to 400 μm. Here, the average fiber length means a number average fiber length showing the average value of the lengths of all the corresponding fibers. For example, the average fiber length of 200 μm means that 50 mineral fibers used as a raw material for the friction material composition 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 invention is preferably biosoluble from the viewpoint of harm to the human body. The biosoluble mineral fiber referred to here is a mineral fiber having a characteristic that even if it is taken into the human body, it is partially decomposed in a short time and excreted from the body. Specifically, in a short-term biopermanent test by breathing, the chemical composition is 18% by mass or more of the total amount of alkaline oxides and alkaline earth oxides (total amount of oxides of sodium, potassium, calcium, magnesium, and barium). Indicates fibers with a mass half-life of 20 μm or larger within 40 days, no evidence of excessive carcinogenicity in intraperitoneal studies, or no associated pathogenicity or tumorigenesis in long-term respiratory studies (EU Directive 97). / 69 / EC Nota Q (carcinogenic exemption)). Examples of such biodegradable mineral fibers include SiO ₂ -Al ₂ O ₃ -CaO-MgO-FeO-Na ₂ O-based fibers, which include SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, and Na. Examples thereof include fibers containing ₂ O or the like in any combination. As a commercial product, LAPI NUS FIBERS B. The Rolexul series made by V can be mentioned. "Roxul" includes SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O and the like.

As the metal fiber, copper or a copper alloy fiber can be used in order to improve crack resistance and wear resistance. However, when copper or a copper alloy fiber is contained, the total content of copper in the friction material composition needs to be in the range of 5% by mass or less as a copper element in consideration of environmental friendliness. ..
As the copper or copper alloy fiber, copper fiber, brass fiber, bronze fiber and the like can be used, and these can be used alone or in combination of two or more.

Further, as the metal fiber, a metal fiber other than copper and a copper alloy may be used from the viewpoint of improving the friction coefficient and crack resistance, but the content is 0.5 from the viewpoint of improving wear resistance and suppressing metal catch. Must be less than or equal to mass%. Preferably, it does not contain metal fibers other than copper and copper alloy (content 0% by mass) because the wear resistance is deteriorated and metal catch is likely to occur in spite of the improvement of the coefficient of friction.
Examples of metal fibers other than copper and copper alloys include fibers in the form of elemental metals such as aluminum, iron, zinc, tin, titanium, nickel, magnesium, and silicon, or alloys, and fibers containing metals such as cast iron fibers as main components. These can be used alone or in combination of two or more.

As the organic fiber, aramid fiber, cellulose fiber, acrylic fiber, phenol resin fiber (having a crosslinked structure) and the like can be used, and these can be used alone or in combination of two or more, and wear resistance. From the viewpoint of sex, it is preferable to use aramid fiber.
As the carbon-based fiber, flame-resistant fiber, pitch-based carbon fiber, PAN-based carbon fiber, activated carbon fiber and the like can be used, and these can be used alone or in combination of two or more.

The content of the fiber base material in the non-asbestos friction material composition of the present invention is preferably 5 to 40% by mass, more preferably 5 to 20% by mass, and preferably 5 to 18% by mass. More preferred. By setting the content of the fiber base material in the range of 5 to 40% by mass, the optimum porosity as a friction material can be obtained, squeal can be prevented, appropriate material strength can be obtained, and wear resistance is exhibited. , The formability can be improved. The content of the fiber base material includes the content of the metal fiber of copper or a copper alloy.

(Other materials)
In the non-asbestos friction material composition of the present invention, other materials can be blended, if necessary, in addition to the above-mentioned binder, organic filler, inorganic filler, and fiber base material.
For example, in the non-asbestos friction material composition of the present invention, a metal powder such as copper powder, brass powder, bronze powder or the like is blended within a range in which the total content of copper is 5% by mass or less as a copper element. Can be done. Further, from the viewpoint of wear resistance, an organic additive such as a fluorine-based polymer such as PTFE (polytetrafluoroethylene) can be blended.

[Friction material and friction member]
The present invention also provides a friction material and a friction member using the above-mentioned non-asbestos friction material composition.
By molding the non-asbestos friction material composition of the present invention, it can be used as a friction material for disc brake pads of automobiles and the like, brake linings and the like. Since the friction material of the present invention is excellent in wear resistance at high temperatures and metal catch control, it is suitable as a friction material for disc brake pads having a large load during braking.
Further, by using the friction material, it is possible to obtain a friction member formed by forming the friction material as a friction surface. Examples of the friction member that can be formed by using the friction material include the following configurations and the like.

(1) Consists of only friction material.
(2) A configuration having a back metal and a friction material made of the friction material composition of the present invention serving as a friction surface on the back metal.
(3) In the configuration of (2) above, a primer layer for the purpose of surface modification to enhance the adhesive effect of the back metal between the back metal and the friction material, and an object of adhesion between the back metal and the friction material. A structure in which the adhesive layer is further interposed.
The back metal is usually used as a friction member in order to improve the mechanical strength of the friction member, and a metal, fiber reinforced plastic, or the like can be used as the material, for example, iron, stainless steel, or inorganic fiber. Examples include reinforced plastics and carbon fiber reinforced plastics. As the primer layer and the adhesive layer, those usually used for friction members such as brake shoes may be used.

The friction material of the present invention can be produced by using a commonly used method, and is produced by molding the non-asbestos friction material composition of the present invention, preferably by heat and pressure molding.
Specifically, the non-asbestos friction material composition of the present invention is uniformly mixed using a mixer such as a Regige mixer, a pressure kneader, or an Erich mixer, and this mixture is premolded by a molding die. The obtained premolded product is molded at a molding temperature of 130 ° C. to 160 ° C. and a molding pressure of 20 to 50 MPa in 2 to 10 minutes, and the obtained molded product is heat-treated at 150 to 250 ° C. for 2 to 10 hours. The friction material can be manufactured by performing painting, scorch treatment, and polishing treatment as needed.

Since the non-asbestos friction material composition of the present invention is excellent in wear resistance at high temperatures and suppression of metal catch, it is useful as a "upholstery material" for friction members such as disc brake pads and brake linings, and further, the friction member. It can also be molded and used as the "underlaying material" of.
The "upholstery material" is a friction material that serves as a friction surface of the friction member, and the "underlay material" is a friction material that is interposed between the friction material that is the friction surface of the friction member and the back metal. It is a layer for the purpose of improving shear strength and crack resistance in the vicinity of the adhesive portion with the back metal.

The present invention will be described in more detail by way of examples, but is not limited by the present invention.
The evaluations shown in Examples (including reference examples) and Comparative Examples were performed as follows.

(1) Evaluation of wear resistance at high temperature The wear resistance is determined by braking 1000 times at a pre-braking brake temperature of 500 ° C., a pre-braking speed of 60 km / h, and a deceleration of 0.3 G, based on the friction material thickness before and after the test. The amount of wear of the friction material was calculated.
(2) Evaluation of metal catch generation In the evaluation of metal catch generation, the pre-braking speed is 60 km / h, the braking conditions are 1.96 m / s ² , 2.94 m / s ² , and 3.92 m / s ² , two times each. After braking a total of 36 times to raise the pre-braking temperature from 50 ° C to 300 ° C at 50 ° C intervals, the temperature is lowered from 250 ° C to 50 ° C at 50 ° C intervals, and a total of 30 times under the same braking conditions as described above. Braking was done. After the test was completed, the size and number of metal catches formed on the sliding surface of the friction material were evaluated according to the following criteria.
A: No metal catch generation B: 1 to 2 metal catches with a major axis of less than 2 mm are generated C: 3 or more metal catches with a major axis of less than 2 mm are generated D: 1 or more metal catches with a major axis of 2 mm or more are generated (3) ) Evaluation of friction coefficient The friction coefficient was measured based on the Japanese Automotive Standards Organization JASO C406, and the average value of the friction coefficient in the second efficacy test was calculated.

The wear resistance, metal catch generation, and friction coefficient were evaluated using an inertia of 7 kgf · m · s ² using a dynamometer. In addition, a ventilated disc rotor (manufactured by Kiriu Corporation, material FC190) and a general pin slide type collet type caliper were used.

[Examples (including reference examples) 1 to 13 and Comparative Examples 1 to 5]
Preparation of Disc Brake Pads The materials were blended according to the blending ratio shown in Table 1 to obtain friction material compositions of Examples (including reference examples) and Comparative Examples. The unit of the blending amount of each component in Table 1 is mass% in the friction material composition.
This friction material composition was mixed with a Ladyge mixer (manufactured by Matsubo Co., Ltd., trade name: Ladyge mixer M20), and this mixture was preformed by a molding press (manufactured by Oji Kikai Kogyo Co., Ltd.). The molded product was heat-press molded with a backing metal manufactured by Hitachi Automotive Systems Co., Ltd. using a molding press (manufactured by Sanki Seiko Co., Ltd.) for 5 minutes under the conditions of a molding temperature of 145 ° C and a molding pressure of 30 MPa, and the obtained molded product was obtained. It was heat-treated at 200 ° C. for 4.5 hours, polished using a rotary polishing machine, and scorch-treated at 500 ° C. to obtain a disc brake pad (friction material thickness 11 mm, friction material projected area 52 cm ² ).
Table 1 shows the results of the above evaluation of the manufactured disc brake pads.

The various materials used in Examples (including reference examples) and Comparative Examples are as follows.
(Binding material)
-Phenol resin: manufactured by Hitachi Kasei Kogyo Co., Ltd. (trade name: HP491UP)
(Organic filler)
-Cashew dust: Made by Tohoku Chemical Industry Co., Ltd. (Product name: FF-1056)
(Inorganic filler)
・ Titanate 1: Made by Otsuka Chemical Co., Ltd. (Product name: Terraces L)
Ingredients: Lithium-titanium potassium, Shape: Phosphorus
Median diameter: 25 μm, specific surface area: 0.6 m ² / g
-Titanate 2: Made by Otsuka Chemical Co., Ltd. (Product name: Terraces PS)
Ingredients: Potassium magnesium titanate, Shape: Phosphorus
Median diameter: 4 μm, specific surface area: 2.5 m ² / g
-Titanate 3: Made by Otsuka Chemical Co., Ltd. (Product name: Terraces TF-S)
Ingredient: Potassium titanate, Shape: Phosphorus
Median diameter: 7 μm, specific surface area: 3.5 m ² / g
-Titanate 4: Made by Kubota Co., Ltd. (Product name: TXAX-MA)
Ingredients: potassium titanate, shape: plate
Specific surface area: 1.5m ² / g
-Titanate 5: Made by Toho Material Co., Ltd. (Product name: TOFIX-S)
Ingredients: potassium titanate, shape: columnar
Median diameter: 6 μm, specific surface area: 0.9 m ² / g
-Titanate 6: Made by Otsuka Chemical Co., Ltd. (Product name: Tismo D)
Ingredients: potassium titanate, shape: fibrous
Specific surface area: 7.0 m ² / g
-Zirconium oxide 1: Manufactured by Daiichi Rare Element Chemical Industry Co., Ltd. (Product name: BR-3QZ, average particle diameter 2.0 μm, maximum particle diameter 15 μm)
Zirconium oxide 2: Manufactured by Daiichi Rare Element Chemical Industry Co., Ltd. (Product name: BR-QZ, average particle diameter 6.5 μm, maximum particle diameter 26 μm)
Zirconium oxide 3: Manufactured by Daiichi Rare Element Chemical Industry Co., Ltd. (Product name: BR-12QZ, average particle diameter 8.5 μm, maximum particle diameter 45 μm)
-Graphite: manufactured by TIMCAL (trade name: KS75)
(Fiber base material)
-Aramid fiber (organic fiber): manufactured by Toray DuPont Co., Ltd. (trade name: 1F538)
-Iron fiber (metal fiber): Made by GMT (trade name: # 0)
-Copper fiber (metal fiber): manufactured by Sunny Metal (trade name: SCA-1070)
-Mineral fiber (inorganic fiber): LAPINUS FIBERS B. Made of V (Product name: RB240 Roxul 1000, average fiber length 300 μm)

In the examples, the amount of friction material worn at 500 ° C. was small, excellent wear resistance was exhibited, metal catch could be suppressed, and a high coefficient of friction was exhibited. Comparative Example 2 containing no zirconium oxide, Comparative Example 1 containing zirconium oxide having a maximum particle size of more than 30 μm, Comparative Example 3 in which the content of titanate was less than 10% by mass, and the content of titanate was 35 mass. In Comparative Example 4 containing 1% by mass of iron fiber and Comparative Example 5 containing 1% by mass of iron fiber, sufficient wear resistance could not be obtained and metal catch could not be suppressed.

The non-asbestos friction material composition of the present invention is environmentally friendly because it produces less copper in the wear powder during braking as compared with the conventional product, has excellent wear resistance at high temperatures, and suppresses the formation of metal catches. Therefore, it is useful for friction materials and friction members such as disc brake pads and brake linings of automobiles.

Claims (7)

A friction material obtained by molding a friction material composition containing a binder, an organic filler, an inorganic filler and a fiber base material.
The content of copper in the friction material composition is 5% by mass or less as a copper element, and the content of metal fibers other than copper and copper alloy is 0.5% by mass or less, which corresponds to the inorganic filler. The content of titanate is 13 to 24% by mass, the content of zirconium oxide corresponding to the inorganic filler is 5 to 30% by mass, and the content of zirconium oxide having a particle size of more than 30 μm is 1.0% by mass. % Or less, and further contains cashew dust corresponding to the organic filler and a rubber component corresponding to the organic filler , and their mass ratio (cashew dust: rubber component) is 2: 1 to 10. A friction material that is 1. The friction material according to claim 1, wherein the rubber component is at least one selected from the group consisting of tire rubber, acrylic rubber, isoprene rubber, NBR (nitrile butadiene rubber), and SBR (styrene butadiene rubber). The friction material according to claim 1 or 2, wherein the fiber base material is at least one selected from the group consisting of inorganic fibers, metal fibers, organic fibers and carbon-based fibers. The friction material according to any one of claims 1 to 3, wherein the content of the fiber base material is 5 to 40% by mass. The friction material according to any one of claims 1 to 4, wherein the specific surface area of the titanate is 0.5 to 2.5 m ² / g. The friction material according to any one of claims 1 to 5, wherein the content of the organic filler is 1 to 10% by mass. A friction member formed by using the friction material according to any one of claims 1 to 6 and a back metal.