JP2017002230A - Friction material composition, and friction material and friction member using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a friction material composition which can provide a friction material having excellent friction coefficients, abrasion resistance, and aggressiveness to partner materials at the time of high-speed and high-load braking, even when the composition does not contains copper which may become a cause to pollute rivers, lakes, and oceans, or the content of copper, or even if the composition contains copper, and is 0.5 mass% or less; and, further, a friction material and a friction member using the friction material composition.SOLUTION: The friction material composition comprises a binder, organic filler, inorganic filler, and a fiber substrate, where the friction material composition has a copper content of less than 0.5 mass% as a copper element or does not contain any copper, does not contain antimony as the inorganic filler, contains as the inorganic filler 1 to 50 mass% of particles having a melting point of 2000°C or more, Vickers hardness of 500 to 1500, and an average particle diameter of 15 to 50 μm, 5 to 30 mass% of a titanate, and contains 5 mass% or less of ferrous fibers as a fiber substrate or does not contain the same.SELECTED DRAWING: None

Description

  The present invention relates to a friction material composition containing no asbestos, a so-called non-asbestos friction material composition, and further relates to a friction material and a friction member using the same. Specifically, it is suitable for friction materials such as disc brake pads and brake linings used for braking in automobiles, especially disc brake pads that have a large load during braking. The present invention relates to a friction material composition having a low friction coefficient and excellent wear resistance, and further relates to a friction material and a friction member using the friction material composition.

  Conventionally, disc brakes and drum brakes are used as braking devices for automobiles, and disc brake pads and brake shoes in which a friction material is bonded to a metal base member such as steel are used as friction members. Yes.

  The friction material includes a semi-metallic friction material containing 30% by mass or more and less than 60% by mass of steel fiber as a fiber base material based on the total amount of the friction material composition. It is classified into low steel friction material containing less than 30% by mass with respect to the total amount of the friction material composition, and NAO (Non-Asbestos-Organic) material containing almost no steel fibers such as steel fiber and stainless steel as the fiber base material. Yes.

  In recent years, there is a demand for friction materials that generate less brake noise. Steel fibers and steel-based fibers are not included, and non-ferrous metal fibers, organic fibers, inorganic fibers and other fiber base materials, thermosetting resins, etc. Friction members using friction materials made of NAO materials, which are made of friction modifiers such as binders, organic fillers, inorganic fillers, inorganic abrasives, lubricants and metal particles, have been widely used. (Patent Document 1)

  By the way, as the friction material, a friction material composition containing a binder, a fiber base material, an inorganic filler, an organic filler, and the like is used. A friction material composition in which two or more kinds are combined is used. In particular, copper is blended into the friction material in the form of fibers and powders, and is an effective component for maintaining the friction coefficient under high-temperature braking conditions (fading resistance), improving wear resistance at high temperatures, and improving the strength of friction materials. It is. However, friction materials containing copper contain copper in the abrasion powder generated during braking, and it is suggested that it may cause river, lake, marine pollution, etc. .

  Due to such environmental considerations, friction materials that do not contain copper, which is a heavy metal, have been desired, and friction materials made of NAO materials that do not contain copper components such as metallic copper, copper alloys, and copper compounds have been developed. Being started. Therefore, 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 metal such as copper or copper alloy. (See Patent Document 2).

JP2004-10790 JP 2002-138273 A

  However, in the friction material containing no metal such as copper and copper alloy of Patent Document 2, the problem of deterioration of wear resistance and reduction of friction coefficient during high-speed and high-load braking has become obvious due to the removal of copper. ing.

  Since copper is rich in spreadability and has high thermal conductivity, it extends thinly on the surface of the friction material by braking to form a film, contributing to improvement in heat dissipation. However, if copper is not added to the friction material, the friction material is likely to store heat at a high load, and the thermal decomposition of the phenol resin as the binder and the organic fiber as the fiber base material is promoted. Degradation of phenol resin, organic fiber, etc. causes a decrease in the skeleton strength of the friction material, resulting in a rapid wear and a decrease in the friction coefficient.

  In addition, the absence of a copper coating on the friction material surface makes it easier for the contained particles to fall off, resulting in a decrease in the grinding action of the abrasive material. Decrease occurs.

  Therefore, the present invention does not contain copper that may cause pollution of rivers, lakes, oceans, etc., or even if it contains 0.5% by mass or less, high-speed and high-load braking. It is an object of the present invention to provide a friction material composition capable of providing a friction material excellent in friction coefficient, wear resistance and attacking property of the counterpart material, and a friction material and a friction member using the friction material composition. .

  As a result of various studies, the present inventors have found that the above problem can be solved by using a friction material having the following configuration. That is, the friction material composition of the present invention is as follows. A 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 or contained as a copper element. As an inorganic filler, 1-50 mass% of particles having a melting point of 2000 ° C. or higher, a Vickers hardness of 500-1500, and an average particle diameter of 15-50 μm are contained, and a titanate is contained in an amount of 5-30 mass%.

  In the friction material composition of the present invention, it is preferable not to contain antimony as the inorganic filler. Moreover, as said fiber base material, it is preferable that content of an iron-type fiber is 5 mass% or less or does not contain.

  The friction material of the present invention is formed by molding the friction material composition described above.

  The friction member of this invention is shape | molded using the friction material composition formed by shape | molding the said friction material composition, and a back metal.

  When the friction material composition of the present invention is used for friction materials such as disc brake pads and brake linings for automobiles, it does not contain or has a small amount of copper in the wear powder generated during braking, so the load on the environment is small. In addition, it is possible to maintain a high friction coefficient during high speed and high load braking and to exhibit excellent wear resistance. Moreover, the friction material and friction member which have the said characteristic can be provided by using the friction material composition of this invention.

  Hereinafter, the friction material composition of the present invention, the friction material using the same, and the friction member will be described in detail. The friction material composition of the present invention relates to a friction material composition substantially free of asbestos, a so-called non-asbestos friction material composition.

[Friction material composition]
The friction material composition of the present invention is a friction material composition containing a binder, an organic filler, an inorganic filler, and a fiber base material, wherein the copper content in the friction material composition is copper element. 0.5 mass% or less or not contained, and contains 1 to 50 mass% of particles having a melting point of 2000 ° C. or higher, Vickers hardness of 500 to 1500, and an average particle diameter of 15 to 50 μm as an inorganic filler, and titanate It is characterized by containing 5-30 mass%. 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 very little copper in the wear powder generated during braking compared to the conventional product, and Excellent friction coefficient and wear resistance during high-speed and high-load braking.

  The friction material composition of the present invention does not contain copper, which is highly harmful to the environment, or when copper is contained, the copper content is 0.5% by mass or less. For this reason, even if abrasion powder is generated during braking, it does not cause river, lake or marine pollution. In addition, it is preferable not to contain copper.

(Inorganic filler)
The inorganic filler is included as a friction modifier for avoiding deterioration of the heat resistance of the friction material. In the present invention, the inorganic filler is titanate and a melting point of 2000 ° C. or higher, Vickers hardness of 500 to 1500, and average particles. Particles having a diameter of 15 to 50 μm (hereinafter referred to as large-diameter heat-resistant inorganic particles) are essential.

As the titanate, potassium titanate, lithium potassium titanate, magnesium potassium titanate, or the like can be used. The potassium titanate, for _{example, K 2 O · 6TiO 2,} K 2 O · 8TiO 2 , and the like. As lithium potassium titanate, for example, 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 is used. And the like. Table In The titanate magnesium potassium, for _{example, K 0.2-0.7 Mg 0.4 Ti 1.6 O} 3.7-3.95 prepared by mixing a titanium source and a magnesium source and potassium source And the like. These can be used alone or in combination of two or more. Among these, lithium potassium titanate and magnesium potassium titanate are preferable because they further improve the wear resistance at high temperatures.

  As the shape of the titanate, a fiber, a column, a plate, a particle or a scale 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 about the shape of titanate will be described. Of the rectangular parallelepipeds circumscribing the titanate, the longest side of the rectangular parallelepiped having the smallest volume (the circumscribed 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). ), And the shape of titanate is defined by the aspect ratio (L / T, L / B).

  The fibrous titanate is a titanate having an L / T larger than 10 and an L / B larger than 10. For example, Tismo D, Tismo N (both manufactured by Otsuka Chemical Co., Ltd.) and the like can be mentioned.

  The columnar titanate is a titanate having L / T = 2 to 10 and L / B = 2 to 10. And TOFIX-S (manufactured by Toho Material Co., Ltd.).

  The plate-like titanate is a titanate having L / T larger than 10 and L / B smaller than 10. For example, TXAX-A, TXAX-MA, TXAX-KA, TXAX-CT (all manufactured by Kubota Corporation) and the like can be mentioned.

  The particulate titanate is a titanate having an L / T smaller than 10 and an L / B smaller 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 titanates, those having a thin plate shape such as a scale are referred to as scaly titanates. For example, Terraces PS, Terraces PM, Terraces L, Terraces TF-S (both are Otsuka Chemical Co., Ltd.).

  Among the above shapes, in order to further improve the high temperature wear resistance, it is preferable to use a scaly shape, a columnar shape or a plate shape.

  Moreover, an average particle diameter of 1-50 micrometers and a specific surface area of 0.5-10 m <2> / g are preferable. In addition, an average particle diameter is represented by a median diameter, and a median diameter shows the 50% diameter calculated | required from the volume distribution of the laser diffraction method. The specific surface area can be determined by a BET method using nitrogen gas as an adsorption gas.

  The content of titanate in the friction material composition of the present invention is set to 5 to 30% by mass from the viewpoint of improving wear resistance at high temperatures. By setting the titanate content to 5% by mass or more, there is an effect of improving wear resistance. However, when it adds excessively, abrasion resistance will deteriorate on the contrary, a friction coefficient will fall, and it will become easy to produce | generate a metal catch. From this viewpoint, the content of titanate is 30% by mass or less. In addition, it is preferable that content of a titanate is 10-25 mass%, and it is more preferable that it is 15-25 mass%.

  The friction material composition of the present invention contains, as an inorganic filler, particles having a melting point of 2000 ° C. or higher, a Vickers hardness of 500 to 1500, and an average particle size of 15 to 50 μm (large-sized heat-resistant inorganic particles) as essential components. The non-asbestos friction material composition of the present invention contains large-diameter heat-resistant inorganic particles, so that the friction coefficient during braking at high speed and high load such that the temperature of the friction material during braking is 600 ° C. or more is excellent. Cracking properties and wear resistance are exhibited.

  During high-speed, high-load braking where the temperature of the friction material during braking is 600 ° C. or higher, the temperature locally exceeds 1500 ° C. In order to ensure a stable coefficient of friction in such a sliding environment, large heat-resistant inorganic particles having a melting point of 2000 ° C. or higher are used.

  In addition, if the hardness of the large heat-resistant inorganic particles is low, a stable friction coefficient cannot be secured during high-speed and high-load braking, while if the hardness of the large heat-resistant inorganic particles is too high, the large particles Cracks of the heat-resistant inorganic particles are generated or wear of the rotor as a counterpart material is promoted. For this reason, the hardness of the large heat resistant inorganic particles is set to 500 to 1500 in terms of Vickers hardness.

  Furthermore, the addition amount of the large-diameter heat-resistant inorganic particles is 1% by mass or more, so that the effect of improving the friction coefficient, crack resistance, and wear resistance can be obtained at the time of the above high-speed / high-load braking. . On the other hand, if the addition amount of the large-diameter heat-resistant inorganic particles is excessive, the wear resistance and the counterpart material aggression property deteriorate. From this viewpoint, the addition amount of the large heat-resistant inorganic particles is 50% by mass or less. In addition, it is more preferable that it is 5-40 mass%, and, as for the addition amount of a large particle size heat-resistant inorganic particle, it is further more preferable that it is 10-40 mass%.

  Also, by increasing the average particle size of the large heat-resistant inorganic particles to 15 μm or larger than other inorganic fillers, it becomes difficult to fall off supported by a large number of surrounding particles, and by making the average particle size 50 μm or less Aggravation of aggression can be avoided. For this reason, the average particle diameter of the large heat resistant inorganic particles is set to 15 to 50 μm. In addition, as for the particle diameter of a large-diameter heat-resistant inorganic particle, it is more preferable that an average particle diameter is 20-50 micrometers, and it is further more preferable that it is 25-50 micrometers.

  Examples of the large heat-resistant inorganic particles used in the present invention include zirconium oxide (zirconia), magnesium oxide, zirconium silicate (zircon sand), and aluminum oxide (alumina).

  The particle diameter and average particle diameter can be measured using a method such as laser diffraction particle size distribution measurement. For example, it can be measured with a laser diffraction / scattering particle size distribution measuring apparatus LA.920 (manufactured by Horiba).

  In the friction material composition of the present invention, an inorganic filler other than the inorganic particles can be used in combination. The inorganic filler is not particularly limited as long as it is usually an inorganic filler used for a friction material. Other inorganic fillers include, for example, tin sulfide, molybdenum disulfide, iron sulfide, bismuth sulfide, zinc sulfide, calcium hydroxide, calcium oxide, sodium carbonate, calcium carbonate, magnesium carbonate, barium sulfate, dolomite, coke, oxidation Examples thereof include active alumina such as iron, vermiculite, calcium sulfate, graphite, mica, talc, clay, zeolite, mullite, chromite, titanium oxide, silica, and γ-alumina, and these are used alone or in combination of two or more. be able to. 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 friction material composition of the present invention is preferably 30 to 80% by mass, more preferably 40 to 80% by mass, and further preferably 60 to 80% by mass. . By making content of an inorganic filler into the range of 30-80 mass%, deterioration of heat resistance can be avoided. In addition, content of the said inorganic filler includes content of the said titanate and a large particle size heat-resistant inorganic particle.

  The friction material composition of the present invention contains a binder, an organic filler, and a fiber base material in addition to the above inorganic filler. Hereinafter, the binder, the organic filler, and the fiber base material contained in the friction material composition of the present invention will be described.

(Binder)
The binder 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 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 it provides good heat resistance, moldability, and a friction coefficient.

  The content of the binder in the friction material composition of the present invention is preferably 5 to 20% by mass, and more preferably 5 to 10% by mass. By making the content of the binder in the range of 5 to 20% by mass, it is possible to further suppress the strength reduction of the friction material, reduce the porosity of the friction material, and increase the elastic modulus. Vibration performance deterioration can be 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 friction material composition of the present invention is not particularly limited as long as it can exhibit the above performance, and cashew dust, rubber components, etc., which are usually used as an organic filler, can be used. . 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 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. Further 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. 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.

(Fiber substrate)
The fiber base material exhibits a reinforcing action in the friction material.
As the fiber base material contained in the friction material composition of the present invention, inorganic fibers, metal fibers, organic fibers, carbon fibers, etc., which are usually used as fiber base materials, can be used alone or 2 More than one type can be used in combination. In addition, the fibrous base material here does not include the above-described fibrous form of titanate.

As said inorganic fiber, a ceramic fiber, a biodegradable ceramic fiber, a mineral fiber, glass fiber, a silicate fiber etc. can be used, It can use 1 type or in combination of 2 or more types. The mineral fiber referred to here is a man-made inorganic fiber melt-spun mainly composed of blast furnace slag such as slag wool, basalt such as basalt fiber, and other natural rocks, and is a natural mineral containing Al element. Is more preferable. Specifically, those containing SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O, etc., or those containing one or more of these compounds can be used, 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 100-400 micrometers. Here, the average fiber length refers to a number average fiber length indicating an average value of the lengths of all corresponding fibers. For example, the average fiber length of 200 μm indicates that 50 mineral fibers used as a friction material composition raw material are randomly selected, the fiber length is measured with an optical microscope, and the average value is 200 μm.

The mineral fiber used in the present 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 oxides of sodium, potassium, calcium, magnesium, barium) is 18% by mass or more, and in a short-term biopermanent test by respiration, A fiber with a mass half-life of 20 μm or more that is less than 40 days or that has 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. Commercially available products include Roxul series made by LAPINUS FIBERS BV. “Roxul” includes SiO ₂ , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O and the like.

  Moreover, as said metal fiber, you may use metal fibers other than copper and a copper alloy from a viewpoint of friction coefficient improvement and crack resistance, but content is 5 mass% from a viewpoint of an improvement in wear resistance and metal catch suppression. The following is required. Preferably, the wear resistance is deteriorated and metal catches are easily generated for the improvement of the friction coefficient, and therefore metal fibers other than copper and copper alloy are not contained (content 0 mass%).

  Examples of metal fibers other than copper and copper alloys include, for example, fibers in the form of single 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 organic fiber, aramid fiber, cellulose fiber, PBO fiber, acrylic fiber, phenol resin fiber (having a crosslinked structure), etc. can be used, and these can be used alone or in combination of two or more. From the viewpoint of wear resistance, it is preferable to use an aramid fiber.

  As the carbon-based fibers, flame-resistant fibers, pitch-based carbon fibers, PAN-based carbon fibers, activated carbon fibers, 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 friction material composition of the present invention is preferably 5 to 40% by mass, more preferably 5 to 20% by mass, and further preferably 5 to 18% by mass. . By setting the content of the fiber base in the range of 5 to 40% by mass, an optimum porosity as a friction material can be obtained, squeal can be prevented, an appropriate material strength can be obtained, and wear resistance can be exhibited. The moldability can be improved.

(Other materials)
In addition to the binder, organic filler, inorganic filler, and fiber substrate, the friction material composition of the present invention may contain other materials as necessary.
For example, 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]
Moreover, this invention provides the friction material and friction member which used the above-mentioned friction material composition.

By molding the friction material composition of the present invention, it can be used as a friction material for disc brake pads and brake linings of automobiles and the like. Since the friction material of the present invention is excellent in friction coefficient maintenance and wear resistance at high speed and high load, it is suitable for a friction material of 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. 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 a generally used method, and is produced by molding the friction material composition of the present invention, preferably by hot pressing.
Specifically, the 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 to obtain a mixture. 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 resulting 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 composition of the present invention is useful as a “upholstery material” for friction members such as disc brake pads and brake linings because of its excellent friction coefficient maintenance and wear resistance at high speed and high load. It can also be molded and used as a “underlaying material” for the member.

Note that the “upholstery material” is a friction material that becomes the friction surface of the friction member, and the “underlayment material”
It is a layer for the purpose of improving the shear strength and crack resistance in the vicinity of the bonding portion between the friction material and the back metal, which is interposed between the friction material and the back metal which becomes the friction surface of the friction member.

  The present invention will be described in more detail by way of examples, but is not limited by the present invention. Evaluation in this example was performed by the method shown in Table 1, and the results were evaluated according to the evaluation criteria described.

The test was evaluated using a dynamometer with an inertia of 7 kgf · m · s ² . Further, a ventilated disc rotor (manufactured by Kiriu Co., Ltd., material FC190) and a general pin slide type collet type caliper were used.

[Examples 1-14 and Comparative Examples 1-13]
(Production of disc brake pad)
Materials were blended according to the blending ratios shown in Tables 2 and 3, and friction material compositions of Examples and Comparative Examples were obtained. In addition, the unit of the compounding quantity of each component of Table 2 and Table 3 is the mass% in a 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 with 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, Ltd. using a molding press (manufactured by Sanki Seiko Co., Ltd.) for 5 minutes under the conditions of a molding temperature of 150 ° C. and a molding pressure of 30 MPa. It heat-processed at 200 degreeC for 4.5 hours, grind | polished using the rotary grinder, and performed the scorch process of 500 degreeC, and obtained the disc brake pad (thickness of friction material 11mm, friction material projected area 52cm < ² >).

  Table 2 shows the results of the above evaluation on the manufactured disc brake pads.

  Examples 1 to 14 containing 1 to 50% by mass of heat-resistant inorganic particles having large particle diameters are Comparative Examples 2, 6, 8, and 9 containing inorganic particles having a particle diameter of less than 15 μm and particles having a Vickers hardness of less than 500. Compared to 11 and 12, the friction coefficient during fading was excellent while maintaining the same level of wear resistance. Examples 1 to 14 were Comparative Examples 3, 4, and 10 containing particles having a particle diameter of 50 μm or more, Comparative Example 5 having a small content of titanate, and Comparative Example 7 having a large amount of steel fiber added. As compared with Comparative Example 13 containing inorganic particles having a Vickers hardness exceeding 1500, excellent wear resistance was exhibited while maintaining the fade performance.

  The friction material composition of the present invention has a very low content of copper and antimony in the wear powder generated during braking compared to conventional products, so there is little environmental contamination and excellent friction coefficient and resistance to high loads. Since it can exhibit wear, it is useful for friction materials and friction members such as automobile brake pads and brake linings.

Claims (5)

A friction material composition comprising a binder, an organic filler, an inorganic filler, and a fiber substrate,
The copper content in the friction material composition is 0.5% by mass or less or not contained as a copper element,
As an inorganic filler, while containing 1-50 mass% of particles having a melting point of 2000 ° C. or higher, a Vickers hardness of 500-1500, and an average particle size of 15-50 μm,
A friction material composition containing 5 to 30% by mass of titanate.   The friction material composition according to claim 1 or 2, wherein the inorganic filler does not contain antimony.   The friction material composition according to any one of claims 1 to 3, wherein the fiber base material contains 5 mass% or less or no iron-based fiber.   The friction material composition formed by shape | molding the friction material composition of Claims 1-4.   The friction member shape | molded using the friction material composition formed by shape | molding the friction material composition of Claims 1-4, and a back metal.