JP2020094115A - Friction material composition, and friction material and friction member using friction material composition - Google Patents

Abstract

To provide a friction material composition highly stable in friction coefficient, excellent in abrasion resistance, low in attackability to opposite materials, and excellent in fading resistance property even when content of a copper component is less or zero.SOLUTION: There is provided a friction material composition containing a porous composite in which a crystal particle of a titanate compound and an inorganic compound particle with Mohs hardness of 6 or more are bonded, a titanate compound with a laminar crystal structure, and a thermosetting resin, in which the porous composite has pore volume of 5% or more at a pore diameter in a range of 0.01 to 1.0 μm, and content of a copper component is less than 0.5 mass% based on total amount of the friction material composition of 100 mass%.SELECTED DRAWING: Figure 1

Description

The present invention relates to a friction material composition, a friction material using the friction material composition, and a friction member.

Friction materials used for disc brakes, drum brakes, and other brakes, clutches, etc. that make up braking devices for various vehicles and industrial machines have a high coefficient of friction, are stable, and have excellent wear resistance. It is required to have low property. In order to satisfy these characteristics, a friction material formed from a resin composition containing a fibrous filler such as potassium titanate and a thermosetting resin (binding material) such as a phenol resin that binds these fillers Has been used. Fibrous potassium titanate does not damage the mating material (disk rotor) and has excellent friction characteristics, but has an average fiber diameter of 0.1 μm to 0.5 μm and an average fiber length of 10 μm to 20 μm. In many cases, it contains WHO fibers defined by the World Health Organization (WHO) (fibrous particles having a major axis of 5 μm or more, a minor axis of 3 μm or less, and an aspect ratio of 3 or more). Therefore, as a substitute, non-fibrous (plate-like, columnar, shapes having a plurality of convex portions, etc.) titanic acid that can achieve the required characteristics as a friction material while avoiding safety and health concerns. Salt compounds have been proposed and used.

The composition used for the friction material (hereinafter, also referred to as "friction material composition") further contains copper fibers and copper powder in order to improve wear resistance. This is because when the friction material (brake pad) and the mating material (disc rotor) are rubbed, an adhesive coating is formed on the surface of the mating material due to the malleability of copper, and this adhesive coating acts as a protective film. It is believed that a high friction coefficient can be maintained at high temperatures. However, friction materials containing copper have been suggested to contain copper in the abrasion powder generated during braking, which may cause pollution of rivers, lakes, oceans, etc. State law that prohibits the sale of friction materials containing 5 mass% or more of copper after 2021 and 0.5 mass% or more of copper after 2023 and assembling into new vehicles has come into effect. Therefore, in order to reduce the content of the copper component or to reduce the content of the copper component, a friction material composition containing lithium potassium titanate and graphite (Patent Document 1), two or more titanate compounds and ceramic fibers. A friction material composition containing (Patent Document 2), a friction material composition containing a titanate compound having a plurality of convex portions and a biosoluble inorganic fiber (Patent Document 3), and the like have been proposed.

In addition, wear particles of the disc rotor and metal components such as copper fibers and steel fibers contained in the friction material composition fall off, and these aggregate to form a large metal mass that accumulates between the brake pad and the disc rotor. It may happen. It is known that the metal lumps thus aggregated cause abnormal wear of the disc rotor. Therefore, a friction material composition that does not contain metal fibers and copper components, has a plurality of convex shapes as a friction material composition that has stable friction characteristics, is excellent in wear resistance, and has a low attacking property of the mating material. A friction material composition including potassium titanate, an abrasive having a Mohs hardness of 7 or more, and an elastomer-modified phenol resin has been proposed (Patent Document 4).

Further, the friction material is required to have excellent fade resistance. The fade phenomenon is a phenomenon caused by an organic layer in the friction material being gasified as the friction material becomes hot due to braking, and an air layer is formed at a friction interface with the disc rotor. Fade resistance can be improved by suppressing the formation of a vapor layer at the friction interface. To this end, it is effective to increase the porosity of the friction material so that gas can easily permeate from the friction interface. As a method of increasing the porosity of the friction material, it is conceivable to set the molding pressure in the step of binding and forming the raw material mixture to a lower level, but lowering the molding pressure reduces the strength and wear resistance of the friction material. descend.

Therefore, even when the copper component is not contained or the content of the copper component is reduced, titanium is used as a friction material composition that has a high friction coefficient and is stable, has excellent fade resistance, and can reduce the attacking property of the mating material. A porous composite in which crystal grains of an acid salt compound and inorganic compound grains having a Mohs hardness of 6 or more are bonded, and the cumulative pore volume in the pore diameter range of 0.01 to 1.0 μm is 5% or more. A friction material composition containing a porous composite has been proposed (Patent Document 5).

International Publication No. 2012/066698 Pamphlet JP, 2005-59143, A JP, 2013-76058, A JP, 2014-122314, A JP, 2017-114696, A

However, the friction material compositions proposed in Patent Documents 1 to 4 have a problem that the fade resistance is not sufficient. On the other hand, the friction material composition proposed in Patent Document 5 has a problem that the wear resistance is not sufficient. Therefore, it has been difficult to achieve both wear resistance and fade resistance in a friction material composition containing no copper component or a reduced copper component content.

The object of the present invention, even when containing no copper component or when the content of the copper component is reduced, the friction coefficient is high and stable, the wear resistance is excellent, the mating material attacking property is low, and the fade resistance is excellent. Another object of the present invention is to provide a friction material composition, and a friction material and a friction member using the friction material composition.

As a result of intensive studies, the present inventors have found that even when the copper component is not contained or the content of the copper component is reduced, friction including the porous composite and the titanate compound having a layered crystal structure is obtained. It was found that the above problems can be solved by using a material composition, and the present invention has been completed.

That is, the present invention provides the following friction material composition, friction material and friction member.

Item 1. A friction material composition, which is a porous composite in which crystal grains of a titanate compound are bonded to inorganic compound grains having a Mohs hardness of 6 or more, a titanate compound having a layered crystal structure, and a thermosetting resin. The porous composite has a pore volume of 5% or more in a pore diameter range of 0.01 μm to 1.0 μm, and the total amount of the friction material composition is 100% by mass. A friction material composition having a content of less than 0.5% by mass as a copper element.

Item 2 The friction material composition according to Item 1, wherein the titanate compound constituting the porous composite has a tunnel-like crystal structure.

Item 3 The titanate compound constituting the porous composite is A ₂ Ti _n O _(2n+1) [wherein, A is one or more alkali metal excluding Li, and n is a number from 2 to 11]. ] The friction material composition of claim|item 1 or term|claim 2 characterized by these.

Item 4 The content of the inorganic compound constituting the porous composite is 1% by mass to 80% by mass with respect to 100% by mass of the porous composite, and any one of Items 1 to 3. The friction material composition according to item.

Item 5 At least the inorganic compound constituting the porous composite is selected from the group consisting of zirconium silicate, zirconium oxide, silicon oxide, aluminum oxide, silicone carbide, magnesium oxide, iron (III) oxide and chromium (III) oxide. Item 1. The friction material composition according to any one of items 1 to 4, which is one kind.

Item 6. The friction material composition according to any one of Items 1 to 5, wherein the average particle size of the porous composite is 5 μm to 500 μm.

Item 7 The content of the porous composite is 3% by mass to 30% by mass with respect to 100% by mass of the total amount of the friction material composition, and any one of Items 1 to 6. The friction material composition according to item.

8. titanate compound of the layered crystal _{structure, A x M y Ti (2} -y) O 4 wherein, A is one or more alkali metals except Li, M is Li, Mg, One or more selected from Zn, Ga, Ni, Cu, Fe, Al, and Mn, x is 0.5 to 1.0, y is a number of 0.25 to 1.0], A _{0.5 To 0.7} Li _0.27 Ti _1.73 O _{3.85 to 3.95} [wherein A is one or more alkali metals excluding Li] and A _{0.2 to 0.7} Mg _{0 .40} Ti _1.6 O _3.7-3.95 , wherein A is at least one compound selected from the group consisting of one or more alkali metals other than Li. The friction material composition according to any one of items 1 to 7.

Item 9: The friction material composition according to any one of Items 1 to 8, wherein the titanate compound having the layered crystal structure has an average particle diameter of 0.1 μm to 100 μm.

Item 10 The content of the titanate compound having the layered crystal structure is 3% by mass to 30% by mass with respect to 100% by mass of the total amount of the friction material composition, Item 1 to Item 9 The friction material composition according to any one of 1.

Item 11 The friction material composition according to any one of Items 1 to 10, wherein the total amount of the friction material composition is 100% by mass, and the metal fiber content is less than 0.5% by mass.

Item 12. A friction material, which is a molded product of the friction material composition according to any one of Items 1 to 11.

Item 13 A friction member comprising the friction material according to Item 12.

According to the present invention, even when the copper component is not contained or the content of the copper component is reduced, the friction coefficient is high and stable, the wear resistance is excellent, the mating material attacking property is low, and the fade resistance is excellent. It is possible to provide a friction material composition, and a friction material and a friction member using the friction material composition.

3 is a field emission scanning electron microscope (SEM) photograph showing an overall image of particles in the powder obtained in Synthesis Example 1.

Hereinafter, an example of a preferable mode for carrying out the present invention will be described. However, the following embodiments are merely examples. The present invention is not limited to the embodiments described below.

<Friction material composition>
The friction material composition of the present invention comprises a porous composite in which crystal grains of a titanate compound are bonded to inorganic compound grains having a Mohs hardness of 6 or more, a titanate compound having a layered crystal structure, and a thermosetting resin. Contains. The porous composite has a pore volume of 5% or more in a pore diameter range of 0.01 μm to 1.0 μm. The total amount of the friction material composition is 100% by mass, and the content of the copper component is 0.5% by mass or less as a copper element. Other materials can be further contained if necessary. In addition, in this specification, a "friction material composition" means the composition used for a friction material.

When the total amount of the friction material composition is 100% by mass, the content of the copper component is less than 0.5% by mass as a copper element, and preferably the copper component is not contained, so that the environmental load is increased as compared with the conventional friction material composition. Can be less. In the present specification, "does not contain a copper component" means that copper fiber, copper powder, and an alloy containing copper (brass or bronze), and any of the compounds are used as raw materials for the friction material composition. It means not blended.

According to the friction material composition of the present invention, even when the copper component is not contained or the content of the copper component is reduced, it is used as a friction material and has excellent fade resistance and wear resistance, and stable friction characteristics, Moreover, it is possible to impart low aggression to the opponent material.

(Porous composite)
The porous composite used in the present invention is a porous composite in which the crystal grains of the titanate compound and the inorganic compound grains having a Mohs hardness of 6 or more are bonded to each other. And the inorganic compound particles having a Mohs hardness of 6 or more are firmly bonded by sintering and/or fusion bonding.

The above-mentioned porous composite has an integrated pore volume of 5% or more, preferably 10% or more, more preferably 15% or more, and preferably in the range of pore diameters of 0.01 μm to 1.0 μm. It is 40% or less, more preferably 30% or less. If the cumulative pore volume is too small, excellent fade resistance may not be obtained when used in a friction material. Further, if the cumulative pore volume is too large, the bond between the crystal grains of the titanate compound and the crystal grains of the titanate compound and the inorganic compound grains having a Mohs hardness of 6 or more becomes weak, and the porous structure can be maintained. It may disappear. The cumulative pore volume of the porous composite can be measured by the mercury porosimetry method. The maximum value of the pore distribution is preferably in the range of 0.05 μm to 0.30 μm, more preferably in the range of 0.10 μm to 0.25 μm.

The specific surface area of the porous composite is preferably ^{1m 2} / ^g~13m 2 / g, more preferably from ^{3m 2} / ^g~9m 2 / g, more preferably ^{4m 2} / ^g~8m 2 / It is g. The specific surface area can be measured according to JIS Z8830. If the specific surface area is too small, excellent fade resistance may not be obtained when used as a friction material. If the specific surface area is too large, the chemical reaction in the firing step may not be completed.

The content of the inorganic compound having a Mohs hardness of 6 or more in the porous composite is preferably 1% by mass to 80% by mass, and 10% by mass to 70% by mass based on 100% by mass of the porous composite. It is more preferable that the content is 40% by mass to 60% by mass. When the content of the inorganic compound is less than the above lower limit value, the combined effect with the titanate compound may not be sufficiently exhibited. If the content of the inorganic compound is more than the above upper limit, the porous structure may not be maintained, or a compound other than the titanate compound and the inorganic compound having a Mohs hardness of 6 or more may be generated.

The content of the titanate compound in the porous composite is preferably 20% by mass to 99% by mass, and more preferably 30% by mass to 90% by mass, relative to 100% by mass of the porous composite. It is more preferably 40% by mass to 60% by mass. If the content of the titanate compound is less than the above lower limit, the porous structure may not be maintained, or a compound other than the titanate compound and the inorganic compound having a Mohs hardness of 6 or more may be produced. When the content of the titanate compound is more than the above upper limit value, the combined effect with the inorganic compound may not be sufficiently exhibited.

The shape of the particles of the above-mentioned porous composite is spherical (including those having a slight irregularity on the surface but having a substantially spherical shape such as an elliptical cross section), columnar shape (rod shape, columnar shape, prismatic shape, strip shape, Including a columnar shape such as a substantially columnar shape, a substantially rectangular shape as a whole), a plate shape, a block shape, a shape having a plurality of protrusions (amoeba shape, boomerang shape, cruciform shape, sugar flat sugar shape, etc.), indefinite It is a non-fibrous particle such as a shape. Of these, the spherical shape is preferable. The particle size of the porous composite is not particularly limited, but from the viewpoint of further enhancing the dispersibility in the friction material composition, the average particle size is preferably 5 μm to 500 μm, and more preferably 10 μm to 300 μm. The thickness is more preferably 50 μm to 200 μm, still more preferably 70 μm to 150 μm.

The average particle diameter of the porous composite means a particle diameter at a volume-based cumulative 50% in a particle size distribution measured by a laser diffraction method (volume-based cumulative 50% particle diameter), that is, D ₅₀ (median diameter). The volume-based cumulative 50% particle diameter (D ₅₀ ) is obtained by calculating the particle size distribution on a volume basis, and counting the number of particles from the smallest particle size in a cumulative curve with the total volume being 100%. It is the particle size at the point of 50%. Similarly, the volume-based cumulative 10% particle size (D ₁₀ ) and the volume-based cumulative 90% particle size (D ₉₀ ) are calculated from the smallest particle size in the cumulative curve with the total volume of the obtained particle size distribution being 100%. The number of particles is counted, and the particle diameters at the points where the cumulative values are 10% and 90% are shown. Therefore, the ratio of D ₉₀ and D ₁₀ (D ₉₀ /D ₁₀ ) can be regarded as an index showing the breadth of the particle size distribution. The larger the value of D ₉₀ /D ₁₀ , the wider the particle size distribution. Further, as the value of D ₉₀ /D ₁₀ is closer to 1, the particle size distribution is closer to monodisperse.

The D ₉₀ of the porous composite is preferably 400 μm or less, more preferably 350 μm or less. By setting D ₉₀ in the above range, the friction characteristics of the friction material can be further enhanced.

The porous composite has a value of D ₉₀ /D ₁₀ of, for example, 30 or less, and preferably in the range of 1 to 15. When the value of D ₉₀ /D ₁₀ is within the above range, the friction characteristics of the friction material can be further enhanced.

The titanate compound forming the porous composite has a crystal structure such as a layered structure or a tunnel structure, and the tunnel crystal structure is preferable from the viewpoint of further enhancing the stability of the friction coefficient. ..

Examples of the titanate compound having a tunnel-like crystal structure that forms a porous composite include, for example, A ₂ Ti _n O _(2n+1) [wherein, A is one or more alkali metal excluding Li, and n is the number of 2 to _{11], a (2 + y) Ti} (6-x) M x O (13 + y / 2- (4-z) x / 2) wherein, a is one alkali metal except Li or 2 Or more, M is one or more selected from Li, Mg, Zn, Ga, Ni, Cu, Fe, Al, and Mn, z is an valence of the element M, an integer of 1 to 3, and 0.05≦ x≦0.5, 0≦y≦(4-z)x] and the like, and preferably A ₂ Ti _n O _(2n+1) [wherein A is an alkali metal excluding Li] 1 or 2 or more thereof, n is a number of 2 to 11], more preferably A ₂ Ti _n O _(2n+1) [wherein A is one of alkali metals excluding Li or Two or more kinds, n is a number of 4 to 8], and more preferably K ₂ Ti _n O _(2n+1) [wherein, n is a number of 4 to 8] and Na ₂ Ti _n O _{( 2n+1)} [In the formula, n is a number of 4 to 8] and at least one compound selected from the group consisting of:

Specific examples of the titanate compound having a tunnel-like crystal structure that forms a porous composite include K ₂ Ti _4.8 O _10.6 (potassium 4.8 titanate) and K ₂ Ti ₆ O ₁₃ (6 titanium). Acid potassium), K ₂ Ti _6.1 O _13.2 (6.1 potassium titanate), K ₂ Ti _7.9 O _16.8 (7.9 potassium titanate), K ₂ Ti ₈ O ₁₇ (8 Potassium titanate), K ₂ Ti _10.9 O _22.8 (potassium titanate 10.9), Na ₂ Ti ₆ O ₁₃ (sodium hexatitanate), Na ₂ Ti ₈ O ₁₇ (sodium octatitanate), K _2.15 Ti _5.85 Al _0.15 O _13.0 (potassium aluminum titanate), K _2.20 Ti _5.60 Al _0.40 O _12.9 (potassium aluminum titanate), K _2.21 Ti _5.90 Li _0.10 O _12.9 (lithium potassium titanate) and the like can be mentioned.

The titanate compound having a layered crystal structure to form a porous composite, for _{example, A x M y Ti (2} -y) O 4 wherein, A is one or more alkali metals except Li , M is one or more selected from Li, Mg, Zn, Ga, Ni, Cu, Fe, Al, and Mn, x is 0.5 to 1.0, and y is 0.25 to 1.0. Number], A _{0.5 to 0.7} Li _0.27 Ti _1.73 O _{3.85 to 3.95} [wherein A is one or more alkali metals excluding Li], A _{0. 2 to 0.7} Mg _0.40 Ti _1.6 O _{3.7 to 3.95} [wherein A is one or more alkali metals excluding Li], A _{0.5 to 0.7} Li _{(0.27-x) M y Ti} (1.73-z) O 3.85~3.95 wherein, a is one or more alkali metals except Li, M is Mg, Zn, One or more selected from Ga, Ni, Cu, Fe, Al and Mn (however, in the case of two or more, combinations of ions having different valences are excluded), x and z, M is a divalent metal , X=2y/3, z=y/3, when M is a trivalent metal, x=y/3, z=2y/3, y is 0.004≦y≦0.4] The compounds mentioned can be mentioned.

Specific examples of the titanate compound having a layered crystal structure forming a porous composite include K _0.8 Li _0.27 Ti _1.73 O ₄ (lithium potassium titanate) and K _0.7 Li _0.27. Ti _1.73 O _3.95 (lithium potassium titanate), K _0.8 Mg _0.4 Ti _1.6 O ₄ (magnesium potassium titanate), K _0.7 Mg _0.4 Ti _1.6 O _{3 .95} (potassium magnesium titanate), K _0.7 Li _0.13 Mg _0.2 Ti _1.67 O _3.95 (lithium magnesium potassium titanate), K _0.7 Li _0.24 Mg _0.04 Ti _1.72 O _3.95 (lithium magnesium potassium titanate), K _0.7 Li _0.13 Fe _0.4 Ti _1.47 O _3.95 (lithium iron potassium titanate) and the like can be mentioned.

Since the porous composite has a small pore diameter as described above, it is possible to prevent the thermosetting resin from impregnating into the porous composite. Therefore, in a friction material formed by molding a friction material composition containing a porous composite, this porous composite becomes a hole for fading gas. Therefore, it is considered that excellent fade resistance can be obtained without adjusting and setting the molding pressure in the step of binding-molding the raw material mixture to be low. Further, the inorganic compound acts as an abrasive and is complexed with the titanate compound, so that the inorganic compound can be hard to fall off from the friction material and can stably exist, and has stable friction characteristics and a mating material. It is thought that the low aggression of can be added. The Mohs hardness of the inorganic compound is limited to 6 or more because the compound effect with the titanate compound can be obtained by using a compound harder than the titanate compound.

The method for producing the porous composite used in the present invention is not particularly limited as long as the above-mentioned properties can be obtained. For example, mechanically pulverizing a titanium source, an alkali metal salt, and an inorganic compound having a Mohs hardness of 6 or more. Examples of the method include a method in which the pulverized mixture obtained in (1) is dry-granulated and fired to produce the mixture.

Mechanical crushing includes a method of crushing while giving a physical impact. Specifically, pulverization with a vibration mill can be mentioned. By performing the pulverization process with the vibration mill, the shear stress due to the grinding of the mixed powder causes the disorder of the atomic arrangement and the decrease of the interatomic distance at the same time, resulting in the atom migration at the contact point of different particles, resulting in the metastable phase. Is believed to be obtained. As a result, a pulverized mixture having high reaction activity can be obtained, the firing temperature described below can be lowered, and unreacted substances can be reduced even if the pulverized mixture is granulated. Mechanical pulverization efficiently gives a shearing stress to the raw material, and thus a dry treatment that does not use water or a solvent is preferable.

The treatment time by mechanical pulverization is not particularly limited, but it is generally preferably within the range of 0.1 hour to 2 hours.

Granulation of the milled mixture is performed by dry granulation without water and solvent. The dry granulation can be carried out by a known method, and examples thereof include rolling granulation, fluidized bed granulation and stirring granulation. Wet granulation is preferable because in the drying step of the granulated product, as the liquid material vaporizes inside the granulated product, as a result, porous composite particles having large voids inside are obtained, and the powder strength decreases. Absent. Further, heating is required to vaporize water and a solvent, and mass productivity is poor.

The temperature for firing the granulated product can be appropriately selected depending on the composition of the titanate compound of interest, but is preferably in the range of 650°C to 1000°C, and in the range of 800°C to 950°C. Is more preferable. The firing time is preferably 0.5 hours to 8 hours, more preferably 2 to 6 hours.

The titanium source is not particularly limited as long as it is a raw material or titanium dioxide that contains titanium element and does not inhibit the production of titanium dioxide by firing, and examples of such a compound include titanium dioxide, titanium suboxide, orthotitanic acid or the like. Examples thereof include salts, metatitanic acid or salts thereof, titanium hydroxide, peroxotitanic acid or salts thereof, and the like. These may be used alone or in combination of two or more. Of these, titanium dioxide is preferable.

Examples of the alkali metal salt include alkali metal carbonates, hydrogen carbonates, hydroxides, organic acid salts such as acetates, sulfates and nitrates, and the carbonates are preferable.

The mixing ratio of the titanium source and the alkali metal salt can be appropriately selected depending on the composition of the target titanate compound.

As the inorganic compound having a Mohs hardness of 6 or more, known inorganic compounds (abrasives) can be used as long as they are used for the purpose of grinding the mating material to improve the friction coefficient when contained in the friction material. it can. Specifically, zirconium silicate (Mohs hardness 7.5), zirconium oxide (Mohs hardness 7.5), silicon oxide (Mohs hardness 7), aluminum oxide (Mohs hardness 9), silicon carbide (Mohs hardness 9), oxidation Magnesium (Mohs hardness 6), iron oxide (III) (Mohs hardness 6), chromium oxide (III) (Mohs hardness 6.5) and the like can be mentioned, and one of these can be used alone or in combination of two or more. Can be used.

Among the above-mentioned inorganic compounds, a Mohs hardness of 6 to 9 is preferable, and a Mohs hardness of 7 to 9 is more preferable from the viewpoint that a high friction coefficient required for braking at high speed and high load can be obtained. Further, in order to form a homogeneous porous composite and to sufficiently express the composite effect with the inorganic compound, the average particle size of the aforementioned inorganic compound is preferably in the range of 1 μm to 10 μm, more preferably 1 μm to 5 μm. Those in the range of are used. The average particle diameter of the above-mentioned inorganic compound refers to a particle diameter at a volume-based cumulative 50% in a particle size distribution measured by a laser diffraction method (volume-based cumulative 50% particle diameter), that is, D ₅₀ (median diameter).

The porous composite used in the present invention has a treatment layer comprising a surface treatment agent on the surface of the porous composite for the purpose of further improving the dispersibility and further improving the adhesion with the thermosetting resin. It may be formed.

Examples of the surface treatment agent include silane coupling agents and titanium coupling agents. Among these, a silane coupling agent is preferable, and an amino silane coupling agent, an epoxy silane coupling agent, and an alkyl silane coupling agent are more preferable. The surface treatment agents may be used alone or in combination of two or more.

Examples of the amino-based silane coupling agent include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane. Methoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2 -Aminoethyl-3-aminopropyltrimethoxysilane and the like can be mentioned.

Examples of the epoxy-based silane coupling agent include 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, triethoxy(3-glycidyloxypropyl)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and the like can be mentioned.

Examples of the alkyl silane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane. , N-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane and the like.

As a method for forming a treatment layer composed of a surface treatment agent on the surface of the porous composite, a known surface treatment method can be used, for example, a solvent that accelerates hydrolysis (for example, water, alcohol or a mixture thereof). The surface treatment agent is dissolved in a mixed solvent) to form a solution, and the solution is sprayed onto the porous composite by a wet method or the like.

The amount of the surface treatment agent when the surface treatment agent is treated on the surface of the porous composite used in the present invention is not particularly limited, but in the case of the wet method, for example, relative to 100 parts by mass of the porous composite. The solution of the surface treatment agent may be sprayed so that the surface treatment agent is 0.1 to 20 parts by mass.

The content of the porous composite in the friction material composition is preferably 3% by mass to 30% by mass, and 5% by mass to 15% by mass, based on 100% by mass of the total amount of the friction material composition. Is more preferable. By setting the content of the porous composite within the above range, more excellent friction characteristics can be obtained.

(Titanate compound having a layered crystal structure)
The titanate compound having a layered crystal structure used in the present invention, for _{example, A x M y Ti (2} -y) O 4 wherein, A is one or more alkali metals except Li, M is One or more selected from Li, Mg, Zn, Ga, Ni, Cu, Fe, Al, and Mn, x is 0.5 to 1.0, and y is a number of 0.25 to 1.0], A _{0.5 to 0.7} Li _0.27 Ti _1.73 O _{3.85 to 3.95} [wherein, A is one or more alkali metals excluding Li], A _{0.2 to 0 .7} Mg _0.40 Ti _1.6 O _3.7~3.95 wherein, a is one or more alkali metals except _{Li], a 0.5~0.7} Li _{(0. 27-x) M y Ti (} 1.73-z) O 3.85~3.95 wherein, a is one or more alkali metals except Li, M is Mg, Zn, Ga, Ni , Cu, Fe, Al, Mn, or two or more thereof (provided that the combination of ions having different valences is excluded in the case of two or more), x and z are when M is a divalent metal, x=2y/3, z=y/3, when M is a trivalent metal, x=y/3, z=2y/3, y is 0.004≦y≦0.4] Can be mentioned.

The titanate compound having a layered crystal structure, preferably _{A x M y Ti (2-} y) O 4 wherein, A is one or more alkali metals except Li, M is Li, Mg, One or more selected from Zn, Ga, Ni, Cu, Fe, Al, and Mn, x is 0.5 to 1.0, y is a number of 0.25 to 1.0], A _{0.5 To 0.7} Li _0.27 Ti _1.73 O _{3.85 to 3.95} [wherein A is one or more alkali metals excluding Li] and A _{0.2 to 0.7} Mg _{0 .40} Ti _1.6 O _{3.7 to 3.95} [wherein A is one or two or more alkali metals excluding Li], and more preferably at least one compound selected from the group consisting of: K _x Li _y Ti wherein, x is 0.5 to 1.0, y is the number of 0.25 to 1.0] _{(2-y) O 4,} K x Mg y Ti (2-y) O ₄ [wherein x is 0.5 to 1.0 and y is a number of 0.25 to 1.0], K _{0.5 to 0.7} Li _0.27 Ti _1.73 O _{3.85 to 3 .95} and K _{0.2 to 0.7} Mg _0.40 Ti _1.6 O _3.7 to _3.95, at least one compound selected from the group consisting of.

Specific examples of the titanate compound particles having a layered crystal structure include K _0.8 Li _0.27 Ti _1.73 O ₄ (lithium potassium titanate) and K _0.7 Li _0.27 Ti _1.73 O _{3 .95} (lithium potassium titanate), K _0.8 Mg _0.4 Ti _1.6 O ₄ (magnesium potassium titanate), K _0.7 Mg _0.4 Ti _1.6 O _3.95 (magnesium titanate) Potassium), K _0.7 Li _0.13 Mg _0.2 Ti _1.67 O _3.95 (lithium magnesium magnesium titanate), K _0.7 Li _0.24 Mg _0.04 Ti _1.72 O _{3. 95} (lithium magnesium potassium titanate), K _0.7 Li _0.13 Fe _0.4 Ti _1.47 O _3.95 (lithium iron potassium titanate), and the like.

The particle shape of the titanate compound having the above layered crystal structure is, for example, spherical (including those having a slight unevenness on the surface, or those having a substantially spherical shape such as an elliptical cross section) and columnar shapes (rod-shaped, columnar-shaped). , Prismatic shape, strip shape, substantially columnar shape, substantially strip shape, etc. as a whole, including plate shape, plate shape, block shape, shape having a plurality of convex portions (amoeba shape, boomerang shape, cross shape) , Non-fibrous particles of irregular shape, etc.). Among these, particles having a plate shape, a column shape, or a particle shape having a plurality of convex portions are preferable from the viewpoint of further increasing the strength of the friction material in a high temperature range. Further, the titanate compound having a layered crystal structure is preferably non-porous particles. These various particle shapes can be arbitrarily controlled by the production conditions, particularly the raw material composition, the firing conditions and the like. The particle shape can be analyzed by, for example, observation with a scanning electron microscope (SEM).

In the present specification, “non-fibrous particles” means the longest major axis L of a rectangular parallelepiped (circumscribing rectangular parallelepiped) having the smallest volume among the rectangular parallelepipeds circumscribing the particles, the next longest side is the minor axis B, and the shortest side is the shortest side. Particles having L/B of less than 5 as a thickness T (B>T). Among the non-fibrous particles, particles having L/B of less than 5 and L/T of 5 or more are called plate-like particles. Further, “having a plurality of convex portions” means that the projected shape on a plane can have a shape having convex portions in two or more directions, which is different from at least a normal polygon, circle, ellipse, or the like. Specifically, the convex portion is a portion corresponding to a portion protruding by applying a polygonal shape, a circle, an ellipse or the like (basic figure) to a photograph (projection view) by a scanning electron microscope (SEM). ..

The volume-based cumulative 50% particle diameter (D ₅₀ ) of the titanate compound having the layered crystal structure is preferably 0.1 μm to 100 μm, more preferably 0.5 μm to 60 μm, and further preferably 1 μm to 40 μm. And particularly preferably 1 μm to 20 μm, and most preferably 1 μm to 10 μm. When the volume-based cumulative 50% particle diameter (D ₅₀ ) is within the above range, the friction characteristics of the friction material can be further enhanced.

The volume-based cumulative 50% particle diameter (D ₅₀ ) refers to the particle diameter when the volume-based cumulative 50% in the particle size distribution measured by the laser diffraction method. This D ₅₀ is the particle size at which the particle size distribution is calculated on a volume basis, and the number of particles is counted from the smallest particle size in the cumulative curve with the total volume being 100%, and the cumulative value is 50%. is there. Similarly, the volume-based cumulative 10% particle size (D ₁₀ ) and the volume-based cumulative 90% particle size (D ₉₀ ) are calculated from the smallest particle size in the cumulative curve with the total volume of the obtained particle size distribution being 100%. The number of particles is counted, and the particle diameters at the points where the cumulative values are 10% and 90% are shown. Therefore, the ratio of D ₉₀ and D ₁₀ (D ₉₀ /D ₁₀ ) can be regarded as an index showing the breadth of the particle size distribution. The larger the value of D ₉₀ /D ₁₀ , the wider the particle size distribution. Further, as the value of D ₉₀ /D ₁₀ is closer to 1, the particle size distribution is closer to monodisperse.

The volume-based cumulative 90% particle size (D ₉₀ ) of the titanate compound having the layered crystal structure is preferably 250 μm or less, more preferably 100 μm or less, further preferably 50 μm or less, and particularly preferably 20 μm. It is below. By setting D ₉₀ in the above range, the friction characteristics of the friction material can be further enhanced.

The titanate compound having the layered crystal structure has a D ₉₀ /D ₁₀ value of, for example, 30 or less, and preferably in the range of 1 to 15. When the value of D ₉₀ /D ₁₀ is within the above range, the friction characteristics of the friction material can be further enhanced.

The specific surface area of the titanium salt compound of the layered crystal structure is preferably 0.3m ² / g~10m ² / g, more preferably 0.5m ² / g~9m ² / g, more preferably is a 0.5m ² / g~3m ² / g. The specific surface area can be measured according to JIS Z8830.

The layered crystal structure titanate compound used in the present invention has a layered crystal structure titanate compound surface for the purpose of further improving the dispersibility and further improving the adhesion with the thermosetting resin. A treatment layer made of a surface treatment agent may be formed.

Examples of the surface treatment agent include silane coupling agents and titanium coupling agents. Among these, a silane coupling agent is preferable, and an amino silane coupling agent, an epoxy silane coupling agent, and an alkyl silane coupling agent are more preferable. The surface treatment agents may be used alone or in combination of two or more.

Examples of the amino-based silane coupling agent include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane. Methoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2 -Aminoethyl-3-aminopropyltrimethoxysilane and the like can be mentioned.

Examples of the epoxy-based silane coupling agent include 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, triethoxy(3-glycidyloxypropyl)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and the like can be mentioned.

Examples of the alkyl silane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane. , N-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane and the like.

As a method for forming a treatment layer comprising a surface treatment agent on the surface of a titanate compound having a layered crystal structure, a known surface treatment method can be used, for example, a solvent that accelerates hydrolysis (for example, water, The surface treatment agent is dissolved in alcohol or a mixed solvent thereof to form a solution, and the solution is sprayed onto a titanate compound having a layered crystal structure by a wet method or the like.

The amount of the surface treatment agent when the surface treatment agent is treated on the surface of the titanate compound having a layered crystal structure used in the present invention is not particularly limited, but in the case of a wet method, for example, titanic acid having a layered crystal structure is used. The surface treatment agent solution may be sprayed so that the amount of the surface treatment agent is 0.1 parts by mass to 20 parts by mass with respect to 100 parts by mass of the salt compound.

In the friction material composition of the present invention, the wear resistance is improved (the pad wear amount is reduced) by using the layered crystal structure titanate compound in combination with the porous composite, and the layered crystal structure titanate compound is further used. Even if is a non-porous particle, the unexpected effect of improving the fade resistance can be obtained.

The content of the titanate compound having a layered crystal structure in the friction material composition is preferably 3% by mass to 30% by mass, and 5% by mass to 15% by mass, based on 100% by mass of the total amount of the friction material composition. More preferably, it is mass %. By setting the content of the titanate compound having the layered crystal structure within the above range, more excellent friction characteristics can be obtained.

The content ratio of the porous composite and the titanate compound having a layered crystal structure is preferably 1:1 to 3:1.

(Thermosetting resin)
The thermosetting resin is used as a binder that integrates with a porous composite, a titanate compound having a layered crystal structure, and the like to give strength. Therefore, any known thermosetting resin used as the binder can be appropriately selected and used.

Examples of the thermosetting resin include phenol resin; elastomer-dispersed phenol resin such as acrylic elastomer-dispersed phenol resin and silicone elastomer-dispersed phenol resin; acrylic-modified phenol resin, silicone-modified phenol resin, cashew-modified phenol resin, epoxy-modified phenol resin, Modified phenol resins such as alkylbenzene-modified phenol resins; formaldehyde resins; melamine resins; epoxy resins; acrylic resins; aromatic polyester resins; urea resins; One of these may be used alone, or two or more may be used in combination. Among these, a phenol resin (straight phenol resin) and a modified phenol resin are preferable because they can further improve heat resistance, moldability, and friction characteristics.

The content of the thermosetting resin in the friction material composition is preferably 5% by mass to 20% by mass based on 100% by mass of the total amount of the friction material composition. By setting the content of the thermosetting resin within the above range, an appropriate amount of the binder is filled in the gaps of the blended material, and more excellent friction characteristics can be obtained.

(Other materials)
In addition to the porous composite, the titanate compound having a layered crystal structure, and the thermosetting resin, the friction material composition of the present invention may be blended with other materials, if necessary. Examples of other materials include the following fibrous base materials and friction modifiers.

As the fiber base material, aromatic polyamide (aramid) fiber, fibrillated aramid fiber, acrylic fiber (a homopolymer or copolymer fiber mainly containing acrylonitrile), fibrillated acrylic fiber, cellulose fiber, fibrillated Organic fibers such as cellulosic fibers and phenolic resin fibers; aluminum, iron, zinc, tin, titanium, nickel, magnesium, silicon and other metals other than copper and copper alloys; Straight or curled metal fiber; glass fiber, rock wool, ceramic fiber, biodegradable ceramic fiber, biodegradable mineral fiber, biosoluble fiber (SiO ₂ —CaO—SrO fiber, etc.), Wollast Inorganic fibers other than titanate fibers such as night fibers, silicate fibers, and mineral fibers; carbon fibers such as flame resistant fibers, PAN-based carbon fibers, pitch-based carbon fibers, and activated carbon fibers; One of these may be used alone, or two or more may be used in combination.

As the friction modifier, unvulcanized or vulcanized rubber powder of tire rubber, acrylic rubber, isoprene rubber, NBR (nitrile butadiene rubber), SBR (styrene butadiene rubber), chlorinated butyl rubber, butyl rubber, silicone rubber, etc.; cashew dust, Organic fillers such as melamine dust and rubber-coated cashew dust; titanate compounds having a tunnel-like crystal structure such as potassium titanate and sodium titanate, calcium carbonate, sodium carbonate, lithium carbonate, calcium hydroxide (slaked lime), vermiculite, Inorganic powders of clay, mica, talc, dolomite, chromite, mullite, etc.; inorganic fillers such as aluminum, zinc, iron, tin and other metals other than copper and copper alloys, metal powders in the form of alloys; silicon carbide (carbonization) Silicon), titanium oxide, alumina (aluminum oxide), silica (silicon dioxide), magnesia (magnesium oxide), zirconia (zirconium oxide), zirconium silicate, chromium oxide, iron oxide (triiron tetraoxide, etc.), chromite, quartz Abrasive materials such as; synthetic or natural graphite (graphite), phosphate-coated graphite, carbon black, coke, antimony trisulfide, molybdenum disulfide, tin sulfide, iron sulfide, zinc sulfide, bismuth sulfide, tungsten disulfide, polytetra Solid lubricants such as fluoroethylene (PTFE); and the like. One of these may be used alone, or two or more may be used in combination.

The content of the other material in the friction material composition is preferably 20% by mass to 89% by mass with respect to 100% by mass of the total amount of the friction material composition.

In the friction material composition of the present invention, from the viewpoint of suppressing abnormal wear of the mating material (disk rotor), it is preferable that the total amount of the friction material composition is 100 mass% and the metal fiber content is less than 0.5 mass %. It is more preferable not to contain metal fibers.

(Method for producing friction material composition)
In the friction material composition of the present invention, (1) each component is mixed with a mixer such as a Ledige mixer (“Ledige” is a registered trademark), a pressure kneader, and an Erich mixer (“Airich” is a registered trademark). Method: (2) A granulated product of a desired component is prepared and, if necessary, the other components are mixed by using a mixer such as a Loedige mixer, a pressure kneader, an Erich mixer, and the like. it can.

The content of each component of the friction material composition of the present invention can be appropriately selected according to desired frictional characteristics, and can be produced by the above production method.

Further, the friction material composition of the present invention may be prepared by preparing a master batch containing a specific constituent component in a high concentration, and adding a thermosetting resin or the like to the master batch and mixing them.

<Friction material and friction member>
In the present invention, the above friction material composition is temporarily molded at room temperature (20° C.), and the obtained temporary molded body is subjected to heat and pressure molding (molding pressure 10 MPa to 40 MPa, molding temperature 150° C. to 200° C.). If necessary, the obtained molded body is heat-treated (150° C. to 220° C., held for 1 hour to 12 hours) in a heating furnace, and then the molded body is subjected to a mechanical processing and a polishing processing to obtain a predetermined shape. A friction material having a shape can be manufactured.

The friction material of the present invention is used as a friction member in which the friction material is formed into a friction surface. Examples of the friction member that can be formed by using the friction material include (1) a structure of only the friction material, (2) a base material such as a backing metal, and a book provided on the base material to provide a friction surface. Examples include a configuration including the friction material of the invention.

The base material is used to further improve the mechanical strength of the friction member, and as the material, metal or fiber reinforced resin can be used. Examples thereof include iron, stainless steel, glass fiber reinforced resin, carbon fiber reinforced resin and the like.

Normally, many fine pores are formed inside the friction material, which serves as an escape route for decomposition products (gas and liquids) at high temperatures to prevent the deterioration of friction characteristics and reduce the rigidity of the friction material. Singing is prevented by improving the sound quality. In a normal friction material, the material composition and molding conditions are controlled so that the porosity is preferably 5% to 30%, more preferably 15% to 30%.

Since the friction member of the present invention is composed of the friction material composition of the present invention, even when the copper component is not contained or the content of the copper component is reduced, the friction coefficient is high and stable, and the wear resistance is high. Is excellent, the attacking property of the mating material is low, and the fade resistance is excellent. Therefore, the friction member of the present invention can be suitably used for various brake systems such as disk pads, brake linings, clutch facings, etc. that constitute a braking device for various vehicles and industrial machines.

Hereinafter, the present invention will be described in more detail based on specific examples.

The present invention is not limited to the following examples, and can be implemented with appropriate modifications without departing from the scope of the invention.

<Production of porous composite>
(Synthesis example 1)
Titanium dioxide, potassium carbonate, and zirconium silicate were weighed so as to be 39.8% by mass of titanium dioxide, 12.6% by mass of potassium carbonate, and 47.6% by mass of zirconium silicate (average particle size 1.1 μm) in a vibration mill. And crushed to mix for 10 minutes. The obtained pulverized mixture was dry-granulated with a high speed mixer and then fired at 850° C. for 4 hours in an electric furnace to obtain a powder.

The obtained powder was confirmed to be a mixed phase composed of K ₂ Ti ₆ O ₁₃ (potassium hexatitanate) and ZrSiO ₄ by an X-ray diffractometer (Ultima IV, manufactured by Rigaku Corporation). The cumulative pore volume of the obtained powder in the pore diameter range of 0.01 μm to 1.0 μm was 22.5%, and the maximum value of the pore distribution was 0.25 μm. The cumulative pore volume was measured using a mercury porosimeter (Poremaster 60-GT, manufactured by Quanta Chrome Co., Ltd.), and the measurement range was 0.0036 μm to 400 μm.

As for the particle size of the obtained powder, D ₅₀ was 109.6 μm, D ₁₀ was 25.3 μm, and D ₉₀ was 304.7 μm. In addition, the specific surface area was 5.28 m ² /g.

The shape of the obtained powder was observed using a field emission scanning electron microscope (SEM). FIG. 1 shows a SEM photograph of the whole image of the particles. From FIG. 1, it can be seen that the obtained powder is spherical particles having fine voids of less than 1 μm among the fine particles.

The physical properties of the obtained powder (porous composite) were confirmed as follows, and the results are shown in Table 1. In addition, Table 1 shows the physical properties of the titanate compounds used in Examples and Comparative Examples.

(Particle size)
The particle size was measured by a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, product number "SALD-2100").

Specifically, the particle size at the time of volume-based cumulative 50% in the particle size distribution measured by a laser diffraction type particle size distribution measuring device, that is, D ₅₀ (median size) was determined.

The particle size at the time of volume-based cumulative 10% in the particle size distribution measured by a laser diffraction type particle size distribution measuring device, that is, D ₁₀ was determined.

The particle size at 90% volume-based accumulation in the particle size distribution measured by a laser diffraction particle size distribution measuring device, that is, D ₉₀ was determined.

_Further, from the ratio of the _{D 90} and _{D 10,} it was determined _D 90 _/ D _10.

(Specific surface area)
The specific surface area was measured by an automatic specific surface area measuring device (manufactured by micromeritics, product number "TriStarII3020").

(Particle shape)
The particle shape was observed with a field emission scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, product number "S-4800").

<Manufacture of friction members>
In Example 1 and Comparative Examples 1 to 4, the materials were blended according to the blending ratio according to Table 1 and mixed with a Loedige mixer. The obtained mixture was pressed at room temperature (20° C.) at a pressure of 0.5 MPa for 5 seconds to produce a temporary molded body. The above-mentioned temporary molded body was fitted into the cavity of the heat-molding mold heated to 150° C., and the back plate (material: steel) coated with the adhesive was placed on the temporary molded body at a pressure of 30 MPa for 240 Pressurized for 2 seconds. The obtained member was put in a constant temperature dryer heated to 220° C. and kept for 9 hours to be completely cured, thereby obtaining a friction member.

<Evaluation of friction member>
The surface (friction surface) of the friction member produced above is polished by 1.0 mm, and a brake effectiveness test is performed based on JASO C406. First fade test fade rate, first fade test Minimum friction coefficient, average friction coefficient, pad The wear amount (friction material wear amount) and the rotor wear amount (counterpart wear amount) were determined. As the rotor, a cast iron rotor belonging to the A type in the ASTM standard was used.

First Fade Test The fade rate was calculated by the following calculation formula. The pad wear amount (friction material wear amount) was obtained from the average value of the thickness reduction amounts by measuring the thickness at any 5 points with a micrometer. The amount of wear of the rotor (the amount of wear of the mating member) was determined from the amount of weight reduction. The porosity of the friction material was measured by impregnation in oil according to JIS D4418. The results are shown in Table 2.

First fade test Fade rate (%)=(minimum friction coefficient/maximum friction coefficient)×100

In Table 2, "phenolic resin" is hexamethylenetetramine-containing novolac type phenolic resin powder, "zirconium silicate" is zirconium silicate having an average particle size of 1.1 µm, and "barium sulfate" has an average particle size of 1. It is 6 μm barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd., “Barium Sulfate MBH-100”), and “rock wool” is rock wool having an average fiber length of 125 μm.

From Table 2, Example 1 containing the porous composite and the titanate having the layered crystal structure is Comparative Example 2 containing only the titanate having the layered crystal structure and Comparative Example containing only the porous composite. It can be seen that, as compared with No. 4, the fade rate in the first fade test is excellent, the minimum friction coefficient in the first fade test is high, and the pad wear amount and the rotor wear amount are small. Further, in Comparative Example 1 containing the porous composite and the titanate having the tunnel-shaped crystal structure, the effect of the present invention is not obtained.

That is, the synergistic effect of accelerating the decomposition of the phenolic resin by the titanate of the layered crystal structure and the rapid discharge of the friction product from the friction surface by the improvement of the grinding effect by the porous composite, the friction coefficient is high and stable, It is considered that it was possible to obtain a friction material having improved wear resistance, low attacking property of the mating material, and excellent fade resistance. As a result, surprisingly, it is possible to obtain a high wear resistance which was not obtained in any of Comparative Example 2 containing only the titanate having the layered crystal structure and Comparative Example 4 containing only the porous composite. Moreover, it is considered that the unexpected effect that excellent fade resistance, stable friction characteristics, and low aggression to the mating material can be realized at the same time was obtained.

Claims (13)

A friction material composition,
A porous composite in which crystal grains of a titanate compound and inorganic compound grains having a Mohs hardness of 6 or more are bonded, a titanate compound having a layered crystal structure, and a thermosetting resin,
The porous composite has a pore volume of 5% or more in a pore diameter range of 0.01 μm to 1.0 μm,
The friction material composition, wherein the content of the copper component is less than 0.5 mass% as a copper element in the total amount of the friction material composition of 100 mass %. The friction material composition according to claim 1, wherein the titanate compound constituting the porous composite has a tunnel crystal structure. The titanate compound constituting the porous composite is A ₂ Ti _n O _(2n+1) [wherein, A is one or more alkali metals excluding Li, and n is a number of 2 to 11]. The friction material composition according to claim 1 or 2, wherein the friction material composition is present. Content of the inorganic compound which comprises the said porous composite is 1 mass%-80 mass% with respect to 100 mass% of the said porous composite, It is characterized by the above-mentioned. The friction material composition as described in one item. The inorganic compound constituting the porous composite is at least one selected from the group consisting of zirconium silicate, zirconium oxide, silicon oxide, aluminum oxide, silicone carbide, magnesium oxide, iron oxide (III) and chromium oxide (III). The friction material composition according to any one of claims 1 to 4, wherein The friction material composition according to any one of claims 1 to 5, wherein the average particle size of the porous composite is 5 µm to 500 µm. Content of the said porous composite is 3 mass%-30 mass% with respect to 100 mass% of the total amount of the said friction material composition, The claim|item 1 characterized by the above-mentioned. The friction material composition according to item. The titanate compound having a layered crystal _{structure, A x M y Ti (2} -y) O 4 wherein, A is one or more alkali metals except Li, M is Li, Mg, Zn, One or more selected from Ga, Ni, Cu, Fe, Al and Mn, x is 0.5 to 1.0, y is a number of 0.25 to 1.0], A _{0.5 to 0} wherein, a is one or more alkali metals except Li] _.7 Li _0.27 Ti _1.73 O _3.85~3.95 and _{a 0.2 to 0.7} Mg _0.40 Ti _1.6 O _3.7-3.95 [wherein A is one or more alkali metals excluding Li] and at least one compound selected from the group consisting of: The friction material composition according to any one of claims 1 to 7. The friction material composition according to any one of claims 1 to 8, wherein the titanate compound having a layered crystal structure has an average particle diameter of 0.1 µm to 100 µm. The content of the titanate compound having the layered crystal structure is 3% by mass to 30% by mass with respect to 100% by mass of the total amount of the friction material composition. The friction material composition according to any one of 1. The friction material composition according to any one of claims 1 to 10, wherein the total amount of the friction material composition is 100% by mass, and the metal fiber content is less than 0.5% by mass. A friction material, which is a molded product of the friction material composition according to any one of claims 1 to 11. A friction member comprising the friction material according to claim 12.