JP5263454B2 - Non-asbestos friction material composition, friction material and friction member using the same - Google Patents

Description

  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 has a low copper content, so it has a low environmental impact, and has shear strength, crack resistance and wear resistance. The present invention relates to a non-asbestos friction material composition having excellent properties, and further to a friction material and a friction member using the non-asbestos friction material composition.

  In automobiles and the like, 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, friction materials containing copper and copper alloys contain copper in the wear powder generated during braking, and it is suggested that it may cause pollution of rivers, lakes, oceans, etc. The movement is growing. Therefore, in order to provide a friction material having good friction coefficient, wear resistance, and rotor wear resistance without including metals such as copper and copper alloys, it is used for brakes including a fiber base material, a binder, and a friction adjusting component. It is proposed that the friction material does not contain heavy metals or heavy metal compounds, contains magnesium oxide and graphite in an amount of 45 to 80% by volume in the friction material, and the ratio of magnesium oxide and graphite is 1/1 to 4/1. (See Patent Document 1).

JP 2002-138273 A

However, with the brake friction material of Patent Document 1, it is difficult to obtain an excellent friction material that satisfies all of shear strength, crack resistance, and wear resistance.
On the other hand, as metal fibers other than copper contained in the friction material, steel fibers such as steel fibers and cast iron fibers are used for the purpose of improving crack resistance, but the disadvantage that iron fibers are highly aggressive against facing materials. There is. In addition, non-ferrous metal fibers such as zinc fibers and aluminum fibers, which are generally used for friction materials as metal fibers other than copper, often have lower heat resistance temperatures than copper and iron-based fibers. There is a problem of worsening wear.
In addition, there is a method using inorganic fibers 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, although the friction resistance can be improved, there arises a problem that the friction coefficient is greatly reduced.
As described above, the friction material with a reduced copper content has poor shear strength, wear resistance and crack resistance, and obtains an excellent friction material satisfying all of the shear strength, crack resistance and wear resistance. It was difficult.

  In view of such a background, the present invention is excellent in shear strength, crack resistance, and wear resistance even when the content of copper that may cause pollution of rivers, lakes, and oceans is small. An object is to provide a non-asbestos friction material composition capable of providing a 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 determined that the non-asbestos friction material composition has a copper content and a content of metal other than copper and copper alloy below a certain level and is fibrillated as a fiber substrate. The inventors have found that the above-mentioned problems can be solved by using acrylic fiber as an essential component, and have completed the present invention.

That is, the present invention is as follows.
(1) A non-asbestos friction material composition containing a binder, an organic filler, an inorganic filler, and a fiber base material, wherein the copper content in the friction material composition is 0.5 mass as a copper element % Non-asbestos friction material composition containing 0.5% by mass or less of metal other than copper and copper alloy and containing fibrillated acrylic fiber as a fiber base material.
(2) The non-asbestos friction material composition according to (1), wherein the content of the fibrillated acrylic fiber is 2 to 8% by mass.
(3) A friction material formed by molding the non-asbestos friction material composition according to (1) or (2).
(4) A friction member formed using a friction material obtained by molding the non-asbestos friction material composition according to (1) or (2) and a back metal.

  The non-asbestos friction material composition of the present invention, when used in friction materials such as automotive disc brake pads and brake linings, has less copper on the abrasion powder generated during braking, and therefore has less environmental impact. Excellent shear strength, crack resistance and wear resistance can be exhibited. 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. In the present invention, the non-asbestos friction material composition, the non-asbestos friction material, and the non-asbestos friction member refer to a friction material composition, a friction material, and a friction member substantially not containing asbestos. Further, in the following description, the non-asbestos friction material composition may be simply referred to as “friction material composition”, the non-asbestos friction material as simply “friction material”, and the non-asbestos friction member as simply “friction member”.
[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 copper content in the friction material composition is copper. It is 0.5 mass% or less as an element, content of metals other than copper and a copper alloy is 0.5 mass% or less, and contains a fibrillated acrylic fiber as a fiber base material.
With the above configuration, the friction material and the friction member using the non-asbestos friction material composition of the present invention have less load on the environment because there is less copper in the wear powder generated during braking than in the conventional product, and Excellent shear strength, crack resistance, and wear resistance are exhibited.

  In the present invention, “the content of copper as a copper element” means a copper element contained in a material containing copper as an element, such as copper alone, a copper alloy, and copper oxide, copper sulfide, and a copper complex. The total content of copper. By setting the copper content to 0.5% by mass or less as a copper element, the environmental load can be reduced as compared with a conventional friction material.

In the present invention, “a metal other than copper and a copper alloy” refers to a simple metal other than copper and an alloy containing no copper. For example, a single metal such as aluminum, iron, zinc, tin, titanium, zirconium, nickel, chromium, magnesium, silicon, germanium, or an alloy thereof, or a material mainly composed of a metal such as cast iron is applicable. Examples of the form include fibers and powders of the metal simple substance or alloy.
The non-asbestos friction material composition of the present invention requires that the content of metals other than copper and copper alloys is 0.5% by mass or less, and is preferably substantially free (content 0% by mass). . Thereby, deterioration of the wear resistance of the friction material can be prevented.
In the present invention, the “content of metals other than copper and copper alloys” does not include the content of metal elements in metal oxides, metal sulfides, metal complexes, and the like.

Next, each component contained in the friction material composition of the present invention will be described.
(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. As the binder contained in the non-asbestos friction material composition of the present invention, any thermosetting resin that is usually used as a binder for friction materials can be used without particular limitation.
Examples of the thermosetting resin include various elastomer-dispersed phenol resins / acrylic-modified phenol resins such as phenol resin / acrylic elastomer-dispersed phenol resin, silicone elastomer-dispersed phenol resin, silicone-modified phenol resin, cashew-modified phenol resin, and epoxy-modified phenol. 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 15% by mass, and 7 to 15% by mass. Is more 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, and to reduce the porosity of the friction material and to make noise such as squeal due to the increase in the elastic modulus. Vibration performance deterioration can be further 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 combination. A combination of the above can be used.
Cashew dust and a rubber component may be used in combination, or cashew dust coated with a rubber component may be used. As the organic filler, it is preferable to use cashew dust and a rubber component in combination from the viewpoint of sound vibration performance.

  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 15% by mass, and 5 to 15% by mass. More preferably. By setting the content of the organic filler in the range of 1 to 20% by mass, the elastic modulus of the friction material is increased, deterioration of sound vibration performance such as squealing can be avoided, heat resistance deterioration, heat It is possible to avoid a decrease in strength due to history. Moreover, when using cashew dust and a rubber component together, it is preferable that the mass ratio (cashew dust / rubber component) of cashew dust and a rubber component is the range of 0.2-10, 0.3-5 A range is more preferable.

(Inorganic filler)
The inorganic filler is included as a friction modifier for avoiding deterioration of the heat resistance of the friction material. As the inorganic filler contained in the non-asbestos friction material composition of the present invention, any inorganic filler that is usually used for a friction material can be used without particular limitation.
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, graphite, mica, iron oxide, vermiculite, granular potassium titanate, calcium sulfate, plate-like potassium titanate, talc, clay, zeolite, zirconium silicate, zirconium oxide, mullite, chromite, titanium oxide, magnesium oxide, silica, Examples thereof include activated alumina such as iron oxide and γ-alumina, and these can be used alone or in combination of two or more. From the viewpoint of lowering the aggressiveness to the facing material, it is preferable to contain graphite and barium sulfate.

  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 50 to 80% by mass, and 50 to 70% by mass. More preferably. By making content of an inorganic filler into the range of 30-80 mass%, deterioration of heat resistance can be avoided.

(Fiber base)
The fiber base material exhibits a reinforcing action such as improvement of mechanical strength in the friction material.
The non-asbestos friction material composition of the present invention contains a fibrillated acrylic fiber, which is an organic fiber, as an essential component as a fiber base material from the viewpoint of improving shear strength and crack resistance. A fibrillated acrylic fiber is an acrylic fiber that is split into fibers and has fluff. Examples of the fibrillated acrylic fiber include Sterling fibers Inc. CFF fiber manufactured by the manufacturer can be mentioned and is commercially available. In addition, in this invention, organic fiber means the fibrous material which has organic substance as a main component other than the carbonaceous fiber mentioned later, and is used for the improvement of crack resistance, abrasion resistance, etc.

  The freeness of the fibrillated acrylic fiber is preferably 200 to 315 ml, more preferably 220 to 310 ml, and further preferably 250 to 300 ml. The freeness herein means a CSF (Canadian Standard Freeness) value measured according to TAPPIT-227. By setting the freeness of the fibrillated acrylic fiber in the range of 200 to 315 ml, the friction material exhibits better shear strength, crack resistance, and wear resistance.

The average fiber length of the fibrillated acrylic fiber is preferably 3 to 12 mm, and more preferably 5 to 10 mm. By setting the average fiber length of the fibrillated acrylic fiber in the range of 3 to 12 mm, the shear material, the crack resistance, and the wear resistance superior in the friction material are expressed.
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 means that 50 fiber substrates are selected at random, the fiber length is measured with an optical microscope, and the average value is 200 μm.

  The content of the fibrillated acrylic fiber in the non-asbestos friction material composition of the present invention is preferably 2 to 8% by mass, more preferably 2 to 7% by mass, and 3 to 7% by mass. More preferably it is. When the content of the fibrillated acrylic fiber is 2% by mass or more, excellent shear strength, crack resistance, and wear resistance are exhibited, and when the content is 8% by mass or less, the fibrillated acrylic fiber in the friction material composition And deterioration of shear strength and crack resistance due to uneven distribution of other materials can be further suppressed.

  In the non-asbestos friction material composition of the present invention, a fiber substrate other than the above-described fibrillated acrylic fibers can be further used. Examples of the fiber base other than the fibrillated acrylic fiber include inorganic fibers, metal fibers, organic fibers other than the fibrillated acrylic fiber, and carbon-based fibers that are usually used as the fiber base. A combination of more than one species can be used.

Examples of the inorganic fiber include ceramic fiber, biodegradable ceramic fiber, mineral fiber, glass fiber, potassium titanate fiber, silicate fiber, and wollastonite, and these may be used alone or in combination of two or more. Can do.
From the viewpoint of reducing environmental load substances, among these inorganic fibers, it is preferable not to contain potassium titanate fibers or ceramic fibers that are easily orally sucked into the human body, and SiO ₂ , Al ₂ O ₃ , CaO, MgO, Biodegradable ceramic fibers and biodegradable mineral fibers containing FeO, Na ₂ O and the like in any combination are preferred.

The mineral fiber here is a man-made inorganic fiber that is melt-spun mainly composed of blast furnace slag such as slag wool, basalt such as basalt fiber, and other natural rocks, and is more preferably a natural mineral containing Al element. 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. Among them, those containing Al element can be used as mineral fibers. Since the adhesive strength with each component in the friction material 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.
The mineral fiber used in the present invention 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 sodium, potassium, calcium, magnesium, barium oxide) 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 product, LAPINUS FIBRES B. For example, V Roxul series. “Roxul” includes SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O and the like.

As the metal fibers, copper or copper alloy fibers can be used to improve crack resistance and wear resistance. Examples of the copper or copper alloy fibers include copper fibers, brass fibers, bronze fibers, and the like, and these can be used alone or in combination of two or more.
However, when the fiber of copper or copper alloy is included, the content of the entire copper in the non-asbestos friction material composition of the present invention is in the range of 0.5% by mass or less as the copper element, considering the environmental load. It is necessary to become.

Moreover, you may use metal fibers other than copper and a copper alloy from a viewpoint of a friction coefficient improvement and crack resistance as said metal fiber. Examples of metal fibers other than copper and copper alloys include 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.
From the viewpoint of wear resistance, the content of metals other than copper and copper alloy in the non-asbestos friction material composition of the present invention is required to be in a range of 0.5% by mass or less. From the viewpoint of improving wear resistance, it is preferable not to contain metal fibers other than copper and copper alloys (content 0 mass%).

  Examples of organic fibers other than the fibrillated acrylic fibers include aramid fibers, cellulose fibers, phenol resin fibers (having a crosslinked structure), and the like, and these can be used alone or in combination of two or more.

  Examples of the carbon-based fibers include flame-resistant fibers, pitch-based carbon fibers, polyacrylonitrile (PAN) -based carbon fibers, activated carbon fibers, and the like. 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 30% by mass, including fibrillated acrylic fibers. More preferably, it is 10-30 mass%. By setting the content of the fiber base material in the range of 5 to 40% by mass, an appropriate porosity as a friction material can be obtained, so that deterioration in sound vibration performance such as squeal due to an increase in elastic modulus can be avoided. Moreover, appropriate material strength and wear resistance can be obtained, and the moldability can be further improved.

(Other materials)
Moreover, in the non-asbestos friction material composition of the present invention, in addition to the binder, the organic filler, the inorganic filler, and the fiber substrate, other materials can be blended as necessary.
For example, an organic additive such as a fluorine-based polymer such as polytetrafluoroethylene (PTFE) can be blended for improving wear resistance.

[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 as a friction material for a disk brake pad having a large load during braking.
Furthermore, by using the friction material, a friction member formed so that the friction material becomes a friction surface can be obtained. Examples of the friction member of the present invention 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 non-asbestos 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 back metal is usually used for 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, and examples thereof include iron, stainless steel, inorganic fiber 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 at a molding temperature of 130 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.

The friction material formed by molding the non-asbestos friction material composition of the present invention is excellent as a coefficient of friction, crack resistance and wear resistance, and thus is useful as a “upper material” for friction members such as disc brake pads and brake linings. Furthermore, since it has high crack resistance as a friction material, it can be molded and used as a “underlay material” of a 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.

  Hereinafter, although the non-asbestos friction material composition, the friction material, and the friction member of the present invention will be described in more detail using Examples and Comparative Examples, the present invention is not limited to these.

[Examples 1-5 and Comparative Examples 1-5]
(Production of disc brake pad)
The materials were blended according to the blending ratio shown in Table 1, and the friction material compositions of Examples 1 to 5 and Comparative Examples 1 to 5 were obtained. The friction material composition was mixed with a Readyge mixer (manufactured by Matsubo Co., Ltd., trade name: Ladyge mixer M20), and the mixture was preformed with a molding press (Oji Machinery Co., Ltd.). The obtained preform was heated together with an iron backing (manufactured by Hitachi Automotive Systems) 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. Press molded. The obtained molded product was heat treated at 200 ° C. for 4.5 hours, polished using a rotary polishing machine, and subjected to scorch treatment at 500 ° C., and the disc brake pads of Examples 1-5 and Comparative Examples 1-5 were prepared. Obtained. In Examples and Comparative Examples, a disc brake pad having a back metal thickness of 6 mm, a friction material thickness of 11 mm, and a friction material projection area of 52 cm ² was produced.

(Evaluation of shear strength)
The shear strength was measured based on Japanese Industrial Standard JIS D4422.

(Evaluation of crack resistance)
As for crack resistance, braking with 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 100 ° C. before braking) is half the friction material. The generation of cracks on the friction material side surface and the friction surface was measured repeatedly. The generation of cracks was evaluated according to the following three-point score.
Level 1: No occurrence of cracks 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: 0.1 mm thickness gauge 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.

(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.
Evaluation of the friction coefficient, wear resistance, and crack resistance according to the above-mentioned JASO C406 and JASO C427 was performed using a dynamometer (manufactured by Sanki Seiko Co., Ltd.) and an inertia of 7 kgf · m · s ² . The evaluation was performed using a ventilated disc rotor (material: FC190, manufactured by Kiriu Co., Ltd.) and a general pin slide type collet type caliper.

The evaluation results are shown in Table 1.
In addition, the detail of each structural component in Table 1 is as follows.
(Binder)
Phenolic resin: manufactured by Hitachi Chemical Co., Ltd. (trade name: HP491UP)
(Organic filler)
Cashew dust: manufactured by Tohoku Kako Co., Ltd. (trade name: FF-1056, maximum particle size 500 μm)
(Inorganic filler)
Barium sulfate: manufactured by Sakai Chemical Co., Ltd. (trade name: barium sulfate BA)
Calcium carbonate: Takehara Chemical Industry Co., Ltd. (trade name: Sunlight)
Graphite: manufactured by TIMCAL (trade name: KS75)
Mica: Made by Imeris (Product name: 325HK)
Potassium titanate: manufactured by Kubota Corporation (trade name: TAXA-MA, plate-like potassium titanate)
(Organic fiber)
Fibrilized acrylic fiber: Sterling fibers Inc. (Product name: CFF V110-1, average fiber length 5-6 mm, freeness 267 ml)
Aramid fiber: Toray DuPont Co., Ltd. (trade name: 1F538)
(Metal fiber)
Copper fiber: Sunny metal (trade name: SCA-1070)
Iron fiber: manufactured by GMT (trade name: # 0)
(Inorganic fiber)
Mineral fiber: LAPINUS FIBRES B. V (Product name: RB240Roxul1000, average fiber length 300 μm)

Examples 1 to 5 showed the same level of shear strength, crack resistance, and wear resistance as Comparative Examples 1 and 5 containing a large amount of copper. Moreover, Examples 1-5 do not contain copper, content of metals other than copper and a copper alloy is 0.5 mass% or less, and the comparative example 2 which contains an aramid fiber instead of a fibrillated acrylic fiber And the content of metals other than copper and copper alloys is 0.5 mass% or less, and contains 0.5 mass% as a metal other than copper and copper alloys. Compared to Comparative Example 4 containing iron fibers in an amount exceeding 1, the shear strength, crack resistance, and wear resistance are excellent.
Furthermore, Examples 1-4 which contain content of fibrillated acrylic fiber in the range of 2-7 mass% are further excellent in abrasion resistance compared with Example 5.

  The non-asbestos friction material composition of the present invention, the friction material using the non-asbestos friction material composition, and the friction member have less impact on the environment because of less copper in the wear powder generated during braking compared to conventional products, and are excellent It can exhibit shear strength, crack resistance, and wear resistance, and is suitable for brake pads for passenger cars.

Claims (10)

A non-asbestos friction material composition containing a binder, an organic filler, an inorganic filler, and a fiber base material, wherein the copper content in the friction material composition is 0.5% by mass or less as a copper element Yes, the content of metals other than copper and copper alloys is 0.5% by mass or less, 3 to 7 % by mass of fibrillated acrylic fiber as a fiber base material, and styrene-butadiene rubber as an organic filler. Containing non-asbestos friction material composition.   The non-asbestos friction material composition according to claim 1, comprising at least one selected from a phenol resin, an acrylic-modified phenol resin, a silicone-modified phenol resin, and an alkylbenzene-modified phenol resin as the binder.   The non-asbestos friction material composition according to claim 1 or 2, wherein the freeness of the fibrillated acrylic fiber is 250 to 300 ml.   The non-asbestos friction material composition according to any one of claims 1 to 3, wherein an average fiber length of the fibrillated acrylic fiber is 3 to 12 mm.   The non-asbestos friction material composition according to any one of claims 1 to 4, further comprising a biosoluble mineral fiber as the fiber base material.   The non-asbestos friction according to any one of claims 1 to 5, comprising at least one selected from calcium carbonate, barium sulfate, graphite, mica, granular potassium titanate, and plate-like potassium titanate as the inorganic filler. Material composition.   The non-asbestos friction material composition according to any one of claims 1 to 6, further comprising cashew dust as the organic filler.   The non-asbestos friction material composition according to claim 7, wherein a mass ratio of the cashew dust to the styrene-butadiene rubber is in a range of 0.2 to 10.   The friction material formed by shape | molding the non-asbestos friction material composition in any one of Claims 1-8.   The friction member formed using the friction material formed by shape | molding the non-asbestos friction material composition in any one of Claims 1-8, and a back metal.