WO2012066968A1

WO2012066968A1 - Non-asbestos friction material composition, and friction material and friction member using same

Info

Publication number: WO2012066968A1
Application number: PCT/JP2011/075643
Authority: WO
Inventors: 光朗海野; 一也馬場; 高史菊留
Original assignee: 日立化成工業株式会社
Priority date: 2010-11-19
Filing date: 2011-11-07
Publication date: 2012-05-24
Also published as: JPWO2012066968A1; JP2018127639A; JP6760449B2; JP6079235B2; JP6558465B2; JP6323539B2; JP2019203140A; JP2017075325A

Abstract

Provided is a non-asbestos friction material composition containing a bonding material, an organic filler, an inorganic filler, and a fibrous substrate, said friction material composition being characterised by the content of copper in the friction material composition being at most 5 mass% as elemental copper, the content of metal fibres other than copper and copper alloys being at most 0.5 mass%, and containing lithium potassium titanium oxide and graphite. Even if the content of environmental pollutants such as copper and copper fibres is low, the non-asbestos friction material composition can provide a friction material exhibiting an excellent friction coefficient, crack resistance, and wear resistance. Further provided are a friction material and friction member using the non-asbestos friction material composition.

Description

Non-asbestos friction material composition, friction material and friction member using the same

The present invention relates to a non-asbestos friction material composition, a friction material using the same, and a friction member. Specifically, it is suitable for friction materials such as disc brake pads and brake linings used for braking in automobiles, etc., and because of its low copper content, it can prevent environmental pollution and has a coefficient of friction, crack resistance and wear resistance. And a friction material and a friction member using the non-asbestos friction material composition.

In automobiles, friction materials such as disc brake pads and brake linings are used for braking. The friction material plays a role of braking by rubbing against a facing material such as a disk rotor or 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 make it difficult to scrape the disk rotor that is the facing material (rotor wear resistance) and to make it difficult to squeal (squeal characteristics). In addition, a long pad life (wear resistance) is required. Further, durability performance is required, such as not causing shear fracture during high-load braking (shear strength) and not causing cracks in the friction material due to high-temperature braking history (crack resistance).

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 in order to exhibit the above characteristics. . As the fiber base material, organic fiber, metal fiber, inorganic fiber, or the like is used. In order to improve crack resistance and wear resistance, copper or copper alloy fiber is generally used as the metal fiber. Furthermore, in order to improve wear resistance, a chip or powder of copper or copper alloy may be used. Non-asbestos friction materials are mainly used as friction materials, and copper, copper alloys, and the like are used in large amounts for the non-asbestos friction materials.
However, it has been suggested that friction materials containing copper or a copper alloy contain copper in wear powder generated during braking, which may cause river, lake, marine pollution, and the like.
Therefore, for the purpose of providing a friction material having good friction coefficient, wear resistance, and rotor wear without including metals such as copper and copper alloys, a friction material for brakes including a fiber base material, a binder, and a friction adjusting component. A method is proposed in which 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 without containing a heavy metal or a heavy metal compound. (Patent Document 1).

JP 2002-138273 A

However, with the brake friction material of Patent Document 1, it is difficult to obtain a friction material that is excellent in all of the friction coefficient, crack resistance, and wear resistance.
On the other hand, as metal fibers other than copper contained in the friction material, iron fibers such as steel fibers and cast iron fibers are used for the purpose of improving crack resistance. However, iron fibers have a drawback that the facing material is highly aggressive. There are many non-ferrous metal fibers that are generally used for friction materials other than copper, such as zinc fibers and aluminum fibers. There is a problem of making it worse. In addition, inorganic fibers are used as a method for improving the crack resistance of the friction material. However, in order to obtain sufficient crack resistance, it is necessary to add a large amount of inorganic fiber, and if a large amount of inorganic fiber is used, crack resistance can be improved, but there is a problem that wear resistance deteriorates. .

It is also known that the use of graphite can improve the wear resistance of the friction material. However, in order to obtain sufficient wear resistance, it is necessary to add a large amount of graphite. If a large amount of graphite is used, the wear resistance can be improved, but the friction coefficient is greatly reduced.
As described above, the friction material with a reduced copper content has poor wear resistance and crack resistance, and it is difficult to obtain an excellent friction material that satisfies all of the friction coefficient, crack resistance, and wear resistance. Met.

In view of such background, the problem of the present invention is that the friction coefficient, crack resistance and wear resistance are reduced even if the content of copper or copper alloy which may cause river, lake or marine pollution is small. It is to provide a non-asbestos friction material composition capable of providing an excellent friction material, and a friction material and a friction member using the non-asbestos friction material composition.

As a result of intensive studies, the present inventors have been able to solve the above-mentioned problems by containing copper and metal fibers in a non-asbestos friction material composition at a certain level or less and containing lithium potassium titanate and graphite. The present invention has been completed.
That is, the present invention is as follows.

1. A friction material composition comprising a binder, an organic filler, an inorganic filler, and a fiber base material, wherein the copper content in the friction material composition is 5% by mass or less as a copper element, and copper and a copper alloy A non-asbestos friction material composition characterized in that the content of metal fibers other than is 0.5% by mass or less and contains lithium potassium titanate and graphite.
2. 2. The non-asbestos friction material composition according to 1 above, wherein the content of the lithium potassium titanate in the friction material composition is 1 to 30% by mass.
3. 3. The non-asbestos friction material composition according to 1 or 2 above, wherein the graphite content in the friction material composition is 1 to 20% by mass.
4). 4. A friction material obtained by molding the non-asbestos friction material composition according to any one of 1 to 3 above.
5. A friction member formed by using a friction material obtained by molding the non-asbestos friction material composition according to any one of 1 to 3 above and a back metal.

The non-asbestos friction material composition of the present invention has less environmental pollution because it is used in friction materials such as automotive disc brake pads and brake linings, since there is less copper in the abrasion powder generated during braking, and it is excellent. A friction coefficient, crack resistance, and abrasion resistance can be expressed. Moreover, the friction material and friction member which have the said characteristic can be provided by using the non-asbestos friction material composition of this invention.

Hereinafter, the non-asbestos friction material composition of the present invention, the friction material using the same, and the friction member 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 including a binder, an organic filler, an inorganic filler, and a fiber base material, and the copper content in the friction material composition is as a copper element. It is 5 mass% or less, content of metal fibers other than copper and a copper alloy is 0.5 mass% or less, and contains lithium potassium titanate and graphite.
With the above configuration, since there is less copper in the wear powder generated during braking than in the conventional product, environmental pollution is small, and excellent friction coefficient, crack resistance, and wear resistance can be expressed.

(Binder)
The binding material integrates an organic filler, an inorganic filler, a fiber base, and the like contained in the friction material composition to give strength. There is no restriction | limiting in particular as a binder contained in the non-asbestos friction material composition of this invention, Usually, the thermosetting resin used as a binder of a friction material can be used.
Examples of the thermosetting resins include phenol resins; various elastomer-dispersed phenol resins such as acrylic elastomer-dispersed phenol resins and silicone elastomer-dispersed phenol resins; acrylic-modified phenol resins, silicone-modified phenol resins, cashew-modified phenol resins, and epoxy-modified phenols. Various modified phenol resins such as resins and alkylbenzene-modified phenol resins can be used, 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 good heat resistance, moldability, and friction coefficient are given.

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 binder content in the range of 5 to 20% by mass, the strength of the friction material can be further suppressed, and the porosity of the friction material is reduced and noise such as squeal due to an increase in elastic modulus. Vibration performance deterioration can be suppressed.

(Organic filler)
The organic filler is included 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 usually uses cashew dust, rubber components, etc., which are used as an organic filler. Can do.
The cashew dust is not particularly limited as long as it is obtained by pulverizing a hardened cashew nut shell oil and is usually used for a friction material.
Examples of the rubber component include natural rubber, acrylic rubber, isoprene rubber, polybutadiene rubber (BR), nitrile-butadiene rubber (NBR), and styrene-butadiene rubber (SBR). These may be used alone or in two types. Used in combination. Cashew dust and a rubber component may be used in combination, or cashew dust coated with a rubber component may be used. 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 5 to 10% by mass. It is particularly preferred. By setting the content of the organic filler in the range of 1 to 20% by mass, the elastic modulus of the friction material can be increased, deterioration of sound vibration performance such as squeal can be avoided, heat resistance deterioration, heat 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, and preferably 2: 1 to 8: 1. More preferred is 3: 1 to 8: 1.

(Inorganic filler)
The inorganic filler is included as a friction modifier for avoiding deterioration of the heat resistance of the friction material.
The non-asbestos friction material composition of the present invention contains lithium potassium titanate and graphite as inorganic fillers.
The lithium potassium titanate is not particularly limited as long as it is usually used for a friction material. For example, the composition represented by K _0.5-0.7 Li _0.27 Ti _1.73 O _3.85-3.95 produced by mixing a titanium source, a lithium source and a potassium source can be used.
From the viewpoint of improving the friction coefficient, the average particle size is preferably 1 to 10 μm, more preferably 1 to 8 μm, and particularly preferably 1 to 7 μm. From the viewpoint of reducing environmental substances, the shape is preferably columnar, plate-like, or scale-like.
The content of lithium potassium titanate in the non-asbestos friction material composition of the present invention is preferably 1 to 30% by mass, more preferably 1 to 28% by mass, and 1 to 20% by mass. It is particularly preferred. By setting the content of lithium potassium titanate to 1% by mass or more, a good friction coefficient, crack resistance, and wear resistance are exhibited, and by setting the content to 30% by mass or less, deterioration of wear resistance is avoided. Can do.

As the graphite, either natural graphite or various artificial graphites can be used, and there is no particular limitation as long as it is usually used for a friction material. Examples of natural graphite include earthy graphite, scale-like graphite, and scale-like graphite. Artificial graphite is usually produced by graphitization treatment using petroleum coke or coal-based pitch coke as the main raw material. Examples include graphite and pyrolytic graphite. From the viewpoint of improving the friction coefficient, the average particle size is preferably 0.1 to 100 μm, more preferably 1.0 to 80 μm, and particularly preferably 1.0 to 50 μm.
The content of graphite in the non-asbestos friction material composition of the present invention is preferably 1 to 20% by mass, more preferably 1 to 18% by mass, and preferably 1 to 15% by mass. Particularly preferred. By setting the graphite content to 1% by mass or more, good friction coefficient, crack resistance, and wear resistance are exhibited, and by setting the content to 20% by mass or less, a decrease in the friction coefficient can be avoided.

The non-asbestos friction material composition of the present invention can further contain an inorganic filler other than the above lithium potassium titanate and graphite, and is not particularly limited as long as it is an inorganic filler usually used for a friction material.
Examples of the inorganic filler include antimony trisulfide, tin sulfide, molybdenum disulfide, iron sulfide, bismuth sulfide, zinc sulfide, calcium hydroxide, calcium oxide, sodium carbonate, calcium carbonate, magnesium carbonate, barium sulfate, dolomite, Coke, mica, iron oxide, vermiculite, calcium sulfate, granular potassium titanate, plate-like potassium titanate, talc, clay, zeolite, zirconium silicate, zirconium oxide, mullite, chromite, titanium oxide, magnesium oxide, silica, iron oxide , Activated alumina such as γ-alumina can be used, and these can be used alone or in combination of two or more.

The content of the inorganic filler other than lithium potassium titanate and graphite in the non-asbestos friction material composition of the present invention is preferably 30 to 80% by mass, and more preferably 40 to 80% by mass. 40 to 75% by mass is particularly preferable. By setting the content of the inorganic filler in the range of 30 to 80% by mass, deterioration of heat resistance can be avoided, and this is preferable in terms of the balance of the content of other components of the friction material.

(Fiber base)
The fiber base material exhibits a reinforcing action in the friction material. The fiber base material 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 is usually used as a fiber base material, metal fiber, inorganic fiber, organic fiber, Carbon-based fibers can be used, and these can be used alone or in combination of two or more.

As the metal fibers, copper or copper alloy fibers can be used to improve crack resistance and wear resistance. However, when the copper or copper alloy fiber is contained in the non-asbestos friction material composition of the present invention, the content of the entire copper in the friction material composition is 5 mass as a copper element from the viewpoint of environmental pollution resistance. % Or less, and preferably 0.5% by mass or less.
As the fiber of copper or copper alloy, copper fiber, brass fiber, bronze fiber, or the like can be used, and these can be used alone or in combination of two or more.

In addition, as the metal fiber, from the viewpoint of improving the friction coefficient and crack resistance, metal fibers other than copper and copper alloy may be used in the non-asbestos friction material composition of the present invention, but the wear resistance is deteriorated. From the viewpoint of avoidance, the content needs to be 0.5% by mass or less. On the other hand, since metal fibers other than copper and copper alloys tend to deteriorate the wear resistance for improving the friction coefficient, preferably no metal fibers other than copper and copper alloys are contained (content 0 mass%). It is.
Examples of metal fibers other than copper and copper alloys include, for example, fibers in the form of simple metals or alloys such as aluminum, iron, zinc, tin, titanium, nickel, magnesium, and silicon, and fibers mainly composed of metals such as cast iron fibers. These can be used alone or in combination of two or more.

As the inorganic fiber, ceramic fiber, biodegradable ceramic fiber, mineral fiber, glass fiber, potassium titanate fiber, silicate fiber, wollastonite and the like can be used, and one or a combination of two or more types can be used. Can do.
From the viewpoint of reducing environmental substances, it is preferable not to contain an absorptive potassium titanate fiber or ceramic fiber that is attracted to the lung or the like.

Mineral fibers that can be used in the present invention are artificial inorganic fibers melt-spun mainly composed of blast furnace slag such as slag wool, basalt such as basalt fiber, and other natural rocks, and are natural minerals containing Al elements. More preferably. 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. 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 to 400 μm. 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.

Moreover, it is preferable that the mineral fiber which can be used by this invention is biosoluble from a human body harmful viewpoint. 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-based 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. For example, V Roxul series. “Roxul” includes SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O and the like.

As said organic fiber, an aramid fiber, a cellulose fiber, an acrylic fiber, a phenol resin fiber etc. can be used, These can be used individually or in combination of 2 or more types.
As the carbon-based fiber, flame-resistant fiber, pitch-based carbon fiber, PAN-based carbon fiber, activated carbon fiber, or 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 in the friction material composition, including metal fibers of copper or copper alloy. More preferred is 5 to 15% by mass. By setting the content of the fiber base in the range of 5 to 40% by mass, an appropriate porosity as a friction material can be obtained, squealing can be prevented, an appropriate material strength can be obtained, and wear resistance can be achieved. Formability can be improved.

(Other materials)
The non-asbestos friction material composition of the present invention is blended with other materials as required in addition to the above-mentioned binder, organic filler, inorganic filler, fiber base material, lithium potassium titanate and graphite. Can do.
For example, in the non-asbestos friction material composition of the present invention, the total copper content does not exceed 5 mass% as a copper element, and metal powder such as copper powder, brass powder, bronze powder, etc. is blended. Can do. In addition, 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-described 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 and brake linings for automobiles. Since the friction material of the present invention exhibits a good coefficient of friction, crack resistance, and wear resistance, it is suitable for a friction material for a disk brake pad having a large load during braking.
Furthermore, by using the friction material, it is possible to obtain a friction member in which the friction material is formed to be a friction surface. Examples of the friction member that can be formed using the friction material include the following configurations.

(1) Configuration of friction material only.
(2) The structure which has a back metal and the friction material which consists of a friction material composition of this invention used as a friction surface on this back metal.
(3) In the configuration of (2) above, between the back metal and the friction material, a primer layer for the purpose of surface modification for enhancing the adhesion effect of the back metal, and for the purpose of bonding the back metal and the friction material A configuration in which an adhesive layer is further interposed.
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 Examples thereof 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 of the present invention can be produced by a generally used method, and is produced by molding the non-asbestos friction material composition of the present invention, preferably by hot pressing.
Specifically, the non-asbestos friction material composition of the present invention is uniformly mixed using a mixer such as a Readyge mixer, a pressure kneader, or an Eirich mixer, and this mixture is preformed in a molding die. The obtained preform is molded for 2 to 10 minutes under conditions of a molding temperature of 130 ° C. to 160 ° C. and a molding pressure of 20 to 50 MPa, and the obtained molded product is heat-treated at 150 to 250 ° C. for 2 to 10 hours. A friction material can be manufactured by performing coating, scorch treatment, and polishing treatment as necessary.

Since the non-asbestos friction material composition of the present invention is excellent in friction coefficient, crack resistance, wear resistance, etc., it is useful as a “upper material” for friction members such as disc brake pads and brake linings. Since it has high crack resistance, it can be molded and used as a “underlaying material” of the friction 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.

The present invention will be described in more detail by way of examples, but is not limited by the present invention.
In addition, evaluation shown to an Example and a comparative example was performed as follows.

(1) Evaluation of Friction Coefficient The friction coefficient was measured based on the Japan Society of Automotive Engineers standard JASO C406, and the average value of the friction coefficient in the second efficacy test was calculated.
(2) Evaluation of crack resistance Crack resistance is braking at a brake temperature of 400 ° C. shown in JASO C427 (initial speed 50 km / h, final speed 0 km / h, deceleration 0.3 G, brake temperature before brake 100 ° C.) Was repeated until the friction material had a half thickness, and the generation of cracks on the friction material side surface and the friction surface was measured. The generation of cracks was evaluated according to the following three-point score.
Level 1: No cracks generated Level 2: Cracks to the extent that a 0.1 mm thickness gauge does not enter the friction surface or side surface of the friction material Level 3: A 0.1 mm thickness gauge is formed on the friction surface or side surface of the friction material If a crack that does not contain a thickness gauge is generated on one of the friction surface and the side surface of the friction material and a crack that contains a thickness gauge is generated on the other side, the level 3 is set.
(3) Evaluation of wear resistance The wear resistance was measured based on the Japan Society of Automotive Engineers standard JASO C427, and the wear amount of the friction material corresponding to 1000 brakings at a brake temperature of 100 ° C and 300 ° C was evaluated.

The friction coefficient, wear resistance, and crack resistance according to JASO C406 and JASO C427 were evaluated using a dynamometer at an inertia of 7 kgf · m · s ² . Moreover, it was carried out using a ventilated disc rotor (manufactured by Kiriu Co., Ltd., material FC190) and a general pin slide type collet type caliper.

[Examples 1 to 6 and Comparative Examples 1 to 6]
Preparation of Disc Brake Pads Materials were blended according to the blending ratio shown in Table 1, and friction material compositions of Examples and Comparative Examples were obtained. 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 with a molding press (manufactured by Oji Machinery Co., Ltd.). The pre-molded product was heat-pressed with a backing metal manufactured by Hitachi Automotive Systems, Ltd. using a molding press (manufactured by Sanki Seiko Co., Ltd.) for 5 minutes at a molding temperature of 145 ° C. and a molding pressure of 30 MPa. The molded product was heat treated at 200 ° C. for 4.5 hours, polished with a rotary polishing machine, subjected to scorch treatment at 500 ° C., and a disc brake pad (friction material thickness 11 mm, friction material projection area 52 cm ² ). Got.
Table 1 shows the results of the above evaluations on the manufactured disc brake pads.

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: Tohoku Kako Co., Ltd. (trade name: FF-1090)
・ SBR powder (inorganic filler)
Graphite: manufactured by TIMCAL (trade name: KS75, artificial graphite, sphere, average particle size of about 15 μm)
・ Lithium potassium titanate: manufactured by Otsuka Chemical Co., Ltd.
・ Barium sulfate: manufactured by Sakai Chemical Industry Co., Ltd. (trade name: Barium sulfate BA)
・ Mica Coke: TIMCAL (trade name FC250-1500)
-Tin sulfide: manufactured by Chemetall (trade name Stannolube)
・ Calcium hydroxide and zirconium oxide (fiber base)
・ Aramid fiber (organic fiber): manufactured by Toray DuPont Co., Ltd. (trade name: 1F538)
・ Iron fiber (metal fiber): manufactured by GMT (trade name # 0)
Copper fiber (metal fiber): manufactured by Sunny Metal (trade name SCA-1070)
Mineral fiber (inorganic fiber): LAPINUS FIBERS B. Product made in V (Brand name RB240, average fiber length 300μm)

Examples 1 to 6 showed the same level of friction coefficient, crack resistance and wear resistance as Comparative Example 1 containing a large amount of copper. Examples 1 to 6 are more resistant to cracking than Comparative Examples 2 and 3, which do not contain lithium potassium titanate and graphite, Comparative Example 4 which does not contain graphite, and Comparative Example 5 which does not contain lithium potassium titanate. It is apparent that the wear resistance is excellent and the wear resistance is excellent as compared with Comparative Example 6 containing more than 0.5 mass% of metal fibers other than copper and copper alloy.
Further, the comparison between Examples 1 to 4 and Example 5 shows that wear resistance is further improved by containing 1 to 20% by mass of lithium potassium titanate and 1 to 15% by mass of graphite. It understands.

The non-asbestos friction material composition of the present invention has less environmental pollution due to less copper in the wear powder generated during braking compared to conventional products, and exhibits excellent friction coefficient, crack resistance, and wear resistance. Therefore, it is useful for friction materials and friction members such as disc brake pads and brake linings of automobiles.

Claims

A friction material composition comprising a binder, an organic filler, an inorganic filler, and a fiber base material, wherein the copper content in the friction material composition is 5% by mass or less as a copper element, and copper and a copper alloy A non-asbestos friction material composition characterized in that the content of metal fibers other than is 0.5% by mass or less and contains lithium potassium titanate and graphite.
The non-asbestos friction material composition according to claim 1, wherein the content of the lithium potassium titanate in the friction material composition is 1 to 30% by mass.
The non-asbestos friction material composition according to claim 1 or 2, wherein the graphite content in the friction material composition is 1 to 20 mass%.
A friction material formed by molding the non-asbestos friction material composition according to any one of claims 1 to 3.
A friction member formed by using a friction material obtained by molding the non-asbestos friction material composition according to any one of claims 1 to 3 and a back metal.