JP2020203966A - Friction material composition, friction material, and friction member - Google Patents

Abstract

To provide a friction material composition that has high frictional coefficients and excellent wear resistance even when containing no copper component or containing a reduced content of copper component.SOLUTION: A friction material composition has a non-fibrous titanate compound, mica, and a thermosetting resin. The mica has a volume-based 50% particle size (D50) of less than 10 μm. In the total content 100 mass% of the friction material composition, the content of copper component is less than 0.5 mass% as copper element.SELECTED DRAWING: None

Description

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

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 friction coefficient, are stable, and have excellent wear resistance. It is required to have low sex. 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 them. Has been used. The fibrous potassium titanate does not damage the mating material (disc rotor) and has excellent friction characteristics, but the average fiber diameter is 0.1 μm to 0.5 μm and the average fiber length is 10 μm to 20 μm. It contains WHO fibers (fibrous particles with a major axis of 5 μm or more, a minor axis of 3 μm or less, and an aspect ratio of 3 or more) defined by the World Health Organization (WHO). Therefore, as an alternative, non-fibrous (plate-like, columnar, shape having a plurality of convex portions, etc.) titanium 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") is further blended with copper fiber and copper powder in order to improve wear resistance. This is because when the friction material (brake pad) and the mating material (disc rotor) rub against each other, a cohesive film is formed on the surface of the mating material due to the spreadability of copper, and this cohesive film acts as a protective film. It is believed that a high coefficient of friction can be maintained at high temperatures. However, copper-containing friction materials contain copper in the abrasion powder generated during braking, and it has been suggested that it may cause rivers, lakes, marine pollution, etc., so in California and Washington, USA Since 2021, a state law has been put into effect that prohibits the sale of friction materials containing 5% by mass or more of copper and 0.5% by mass or more of copper after 2023 and the assembly into new vehicles.

Therefore, in order to prevent the copper component from being contained in the friction material composition or to reduce the content of the copper component, a friction material composition containing lithium potassium titanate and graphite (Patent Document 1), a part of titanium sites. A friction material composition containing a titanate compound having a layered crystal structure in which the alkali elution rate is reduced by doping with a plurality of elements (Patent Document 2), a titanate compound having a tunnel-like crystal structure and a layered crystal structure. A friction material composition containing a titanate compound (Patent Document 3), and a friction material composition containing a titanate compound having a layered crystal structure having an alkali elution rate of 0.1% by mass to 2.5% by mass (Patent Document 3). Patent Document 4) and the like have been proposed.

International Publication No. 2012/066968 Pamphlet Japanese Unexamined Patent Publication No. 2015-067508 JP 2015-147913 JP-A-2017-193612

However, even in the friction material compositions proposed in Patent Documents 1 to 4, there is a problem that the friction material composition does not contain a copper component or the content of the copper component is reduced, and the friction characteristics are not sufficient.

An object of the present invention is a friction material composition having a high coefficient of friction and excellent wear resistance even when the copper component is not contained or the content of the copper component is reduced, and friction using the friction material composition. The purpose is to provide materials and friction members.

As a result of diligent studies, the present inventors have conducted a non-fibrous titanate compound, fine mica, and a thermosetting resin even when the copper component is not contained or the content of the copper component is reduced. It has been found that the above-mentioned problems can be solved by using a friction material composition containing and, and the present invention has been completed.

That is, the present invention provides the following friction material compositions, friction materials, and friction members.

Item 1 A friction material composition containing a non-fibrous titanate compound, mica, and a thermosetting resin, wherein the mica has a volume-based 50% particle diameter (D ₅₀ ) of less than 10 μm. A friction material composition, wherein the content of the copper component is less than 0.5% by mass as a copper element in a total amount of 100% by mass of the friction material composition.

Item 2 The friction material composition according to Item 1, wherein the titanate compound is at least one of a titanate compound having a tunnel-shaped crystal structure and a titanate compound having a layered crystal structure.

3. titanate compound of the tunnel-like crystal _structure, wherein, A is one or more alkali metals except Li, n is the number of 2 to 11] _{A 2 Ti n O (2n +} 1) with Item 2. The friction material composition according to Item 2.

4. 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, Mn, x is 0.5 to 1.0, y is 0.25 to 1.0], A _{0.5 ~ 0.7} Li _0.27 Ti _1.73 O _3.85-3.95 [In the formula, A is one or more alkali metals excluding Li], and A _{0.2 ~ 0.7} Mg _0.40 Ti _1.6 O _{3.7 to 3.95 Item 2. In the} formula, A is at least one selected from the group consisting of one or more alkali metals excluding Li]. Friction material composition.

Item 5. Friction according to any one of Items 2 to 4, wherein the titanate compound having a tunnel-shaped crystal structure is particles having a plurality of convex shapes, plate-like particles, columnar particles, or spherical particles. Material composition.

Item 6. The friction material composition according to any one of Items 2 to 5, wherein the titanate compound having a layered crystal structure is plate-like particles.

Item 7. The friction material composition according to any one of Items 1 to 6, wherein the volume-based 50% particle size (D ₅₀ ) of the titanate compound is 0.1 μm to 100 μm.

Item 8 Any one of Items 1 to 7, wherein the content of the titanate compound is 1% by mass to 40% by mass with respect to 100% by mass of the total amount of the friction material composition. The friction material composition according to the section.

Item 9 Any one of Items 1 to 8, wherein the content of the mica is 0.1% by mass to 15% by mass with respect to 100% by mass of the total amount of the friction material composition. The friction material composition according to.

Item A friction material, which is a molded product of the friction material composition according to any one of Items 10 to 9.

Item 11 A friction member comprising the friction material according to item 10.

According to the present invention, a friction material composition having a high coefficient of friction and excellent wear resistance even when the copper component is not contained or the content of the copper component is reduced, and friction using the friction material composition. Materials and friction members can be provided.

Hereinafter, an example of a preferred embodiment of the present invention will be described. However, the following embodiments are merely examples. The present invention is not limited to the following embodiments.

<Friction material composition>
The friction material composition of the present invention contains a non-fibrous titanate compound, mica, and a thermosetting resin. Mica has a volume-based 50% particle diameter (D ₅₀ ) of less than 10 μm. It is characterized in that the content of the copper component is less than 0.5% by mass as a copper element in a total amount of 100% by mass of the friction material composition. Other materials may be further included, if desired. In addition, in this specification, a "friction material composition" means a 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 the copper element, preferably the copper component is not contained, so that the environmental load is increased as compared with the conventional friction material composition. Can be reduced to less. In the present specification, "does not contain a copper component" means that any of copper fibers, copper powder, an alloy containing copper (brass, bronze, etc.), and a compound are used as raw materials for the friction material composition. It means that it is not mixed.

According to the friction material composition of the present invention, even when the friction material composition does not contain a copper component or the content of the copper component is reduced, the friction coefficient is high and excellent wear resistance is imparted when used as a friction material. be able to.

(Titanate compound)
The titaniumate compound used in the present invention has a crystal structure such as a layered structure and a tunnel-like structure, and is at least one of a titaniumate compound having a tunnel-like crystal structure and a titaniumate compound having a layered crystal structure. From the viewpoint of further improving the friction coefficient, a titaniumate compound having a tunnel-like crystal structure is preferable, and from the viewpoint of further improving wear resistance, a titaniumate compound having a layered crystal structure is preferable, and abrasion resistance is preferable. From the viewpoint of further improving both the property and the friction coefficient, it is more preferable to use a titaniumate compound having a tunnel-like crystal structure and a titaniumate compound having a layered crystal structure in combination.

The titanate compounds of the tunnel-like crystal structure, for _{example, A 2 Ti n O (2n} + 1) wherein, A is one or more alkali metals except Li, n is the number of 2 to 11], A _{(2 + y)} Ti _(6-x) M _x O _{(13 + y / 2- (4-z) x / 2)} [In the formula, A is one or more alkali metals excluding Li, M is Li, One or more selected from Mg, Zn, Ga, Ni, Cu, Fe, Al, Mn, z is an integer of 1 to 3 in valence of element M, 0.05 ≦ x ≦ 0.5, 0 ≦ y ≦ (4-z) x ] and the like can be exemplified, preferably in _{a 2 Ti n O (2n +} 1) [wherein, a is one or more alkali metals except Li, n is 2 11 is a number], more in preferably _{a 2 Ti n O (2n +} 1) [wherein, a is one or more alkali metals except Li, n is a number of 4-8], more preferably At least the [wherein, n number of 4 to 8] _{K 2 Ti n O (2n +} 1), and _{Na 2 Ti n O (2n +} 1) wherein, n represents the number of 4-8] is selected from the group consisting of It is one kind.

Specific examples of the titanate compound having a tunnel-like crystal structure include K ₂ Ti _4.8 O _10.6 (4.8 potassium titanate), K ₂ Ti ₆ O ₁₃ (potassium 6 titanate), and 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 (potassium 8 titanate), K ₂ Ti _10.9 O _22.8 (10.9 potassium titanate), Na ₂ Ti ₆ O ₁₃ (sodium 6 titanate), Na ₂ Ti ₈ O ₁₇ (sodium 8 titanate), 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, for _{example, 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, Mn, x is 0.5 to 1.0, y is 0.25 to 1.0], A _{0.5 ~ 0.7} Li _0.27 Ti _1.73 O _3.85-3.95 [In the formula, A is one or more alkali metals excluding Li], A _{0.2 ~ 0.7} Mg _{0 .40} Ti _1.6 O _{3.7 to 3.95} [In the formula, A is one or more alkali metals excluding Li], A _{0.5 to 0.7} Li _(0.27-x) M _y Ti in _{(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, 1 type or 2 or more types (however, in the case of 2 or more types, combinations of ions having different valences are excluded), x and z are x = 2y / when M is a divalent metal. 3, z = y / 3, when M is a trivalent metal, x = y / 3, z = 2y / 3, y is 0.004 ≦ y ≦ 0.4] and the like can be mentioned, preferably A. _{x M y Ti (2-y} ) O 4 wherein, a is one or more alkali metals except Li, M is Li, Mg, Zn, Ga, Ni, Cu, Fe, Al, than Mn One or more selected, x is 0.5 to 1.0, y is 0.25 to 1.0], A _{0.5 to 0.7} Li _0.27 Ti _1.73 O _{3 .85-3.95} [In the formula, A is one or more of alkali metals excluding Li], and A _0.2-0.7 Mg _0.40 Ti _1.6 O _{3.7-3. 95} [In the formula, A is at least one selected from the group consisting of one or more alkali metals excluding Li].

Specific examples of the titanate compound 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} (potassium lithium titanate), K _0.8 Mg _0.4 Ti _1.6 O ₄ (potassium magnesium 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.

The titanate compound used in the present invention is non-fibrous particles, and is, for example, spherical (including those having a slightly uneven surface and those having a substantially spherical shape such as an elliptical cross section) and columnar (rod-shaped). , Cylindrical, prismatic, strip-shaped, substantially cylindrical, substantially strip-shaped, etc., which has a substantially columnar shape as a whole), plate-shaped, block-shaped, and a shape having a plurality of convex portions (amoeba-shaped, boomeran-shaped) , Cross-shaped, golden flat sugar, etc.), and particle shapes such as indefinite shape. Further, the titanate compound may be porous particles. These various particle shapes can be arbitrarily controlled by manufacturing conditions, particularly raw material composition, firing conditions, and the like. In addition, the particle shape can be analyzed from, for example, scanning electron microscope (SEM) observation.

The particle shape of the titanate compound having a tunnel-like crystal structure is preferably particles having a plurality of convex shapes, plate-like particles, columnar particles, or spherical particles. The particle shape of the titanate compound having a layered crystal structure is preferably plate-like particles.

As used herein, the term "non-fibrous particle" means the longest major axis L of a rectangular parallelepiped (circumscribed rectangular parallelepiped) having the smallest volume among the rectangular parallelepipeds circumscribing the particles, the next longest side being the minor axis B, and the shortest side being the thickness. As T (B> T), it means a particle having an L / B of less than 5. Further, "having a plurality of convex portions" means that the projected shape on a plane can take a shape having convex portions in two or more directions, unlike a normal polygon, a circle, an ellipse, or the like. Specifically, this convex portion refers to a portion corresponding to a portion protruding from a polygon, a circle, an ellipse, etc. (basic figure) applied to a photograph (projection drawing) taken by a scanning electron microscope (SEM). ..

The volume-based cumulative 50% particle size (D ₅₀ ) of the titanate compound is preferably 0.1 μm to 100 μm, more preferably 0.5 μm to 60 μm, and even more preferably 1 μm to 40 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 size (D ₅₀ ) refers to the particle size 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 the point where the particle size distribution is obtained on a volume basis, the number of particles is counted from the smallest particle size on the cumulative curve with the total volume as 100%, and the cumulative value becomes 50%. is there. Similarly, for the volume-based cumulative 90% particle diameter (D ₉₀ ), the number of particles is counted from the smallest particle size in the cumulative curve with the total product of the obtained particle size distribution as 100%, and the cumulative value is 90. Indicates the particle size of the point that becomes%.

The volume-based cumulative 90% particle size (D ₉₀ ) of the titanate compound is preferably 100 μm or less, more preferably 80 μm or less, and further preferably 40 μm or less. By setting D ₉₀ in the above range, the number of coarse particles can be reduced, and the friction characteristics of the friction material can be further improved. The lower limit of the volume-based cumulative 90% particle diameter (D ₉₀ ) of the titanate compound is not particularly limited, but may be, for example, 0.1 μm.

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

In the curing reaction of a novolak-type phenol resin as an example of a thermosetting resin used in a friction material composition, for example, hexamethylenetetramine as a curing accelerator opens a ring to bond with a hydroxyl group in the novolak-type phenol resin and cure. The reaction is initiated. However, at this time, if alkali metal ions are present, an ion exchange reaction occurs with hydrogen ions in the hydroxyl groups in the novolak type phenol resin, and hexamethylenetetramine (curing accelerator) and the novolak type phenol resin (thermosetting resin) It is considered to inhibit binding (inhibition of hardening).

Therefore, the alkali metal ion elution rate of the titanate compound is preferably 0.01% by mass to 15% by mass, more preferably 0.05% by mass to 10% by mass, and 0.1% by mass. It is more preferably ~ 5% by mass, and particularly preferably 0.1% by mass to 2.5% by mass. By setting the alkali metal ion elution rate within the above range, it is expected that the curing inhibition of the thermosetting resin during heat and pressure molding can be prevented, and as a result, the crack resistance at high temperature and high load can be improved. In the present invention, the alkali metal ion elution rate refers to the mass ratio of alkali metal ions eluted from the titanate compound in water at 80 ° C.

The titanate compound has a treated layer made of a surface treatment agent formed on the surface of the titanate compound for the purpose of further improving the dispersibility and the adhesion to the thermosetting resin. May be good.

Examples of the surface treatment agent include a silane coupling agent and a titanium coupling agent. Among these, silane coupling agents are preferable, and amino-based silane coupling agents, epoxy-based silane coupling agents, and alkyl-based silane coupling agents are more preferable. The above-mentioned surface treatment agent 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-aminopropyltri. 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, and triethoxy (3-glycidyloxypropyl) silane. Examples thereof include 2- (3,4-epylcyclohexyl) ethyltrimethoxysilane.

Examples of the alkyl-based silane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, and 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 titanate compound, a known surface treatment method can be used, for example, a solvent that promotes hydrolysis (for example, water, alcohol, or a solvent thereof). The surface treatment agent is dissolved in a mixed solvent) to prepare a solution, and the solution is sprayed onto a titanate compound by a wet method or the like.

The amount of the surface treatment agent when treating the surface of the titaniumate compound used in the present invention is not particularly limited, but in the case of the wet method, for example, with respect to 100 parts by mass of the titaniumate compound. The solution of the surface treatment agent may be sprayed so that the amount of the surface treatment agent is 0.1 parts by mass to 20 parts by mass.

The content of the titanate compound in the friction material composition is preferably 1% by mass to 40% by mass, and 5% by mass to 35% by mass, based on 100% by mass of the total amount of the friction material composition. More preferably, it is more preferably 10% by mass to 30% by mass. When the titanate compound having a tunnel-shaped crystal structure and the titanate compound having a layered crystal structure are used in combination, the content ratio should be 30/70 to 70/30 in terms of mass ratio (tunnel-shaped crystal structure / layered crystal structure). Is preferable. By setting the content of the titanate compound within the above range, even more excellent friction characteristics can be obtained.

(Mica)
The mica used in the present invention has a volume-based 50% particle diameter (D ₅₀ ) of less than 10 μm, preferably 0.1 μm or more and less than 10 μm, and more preferably 0.5 μm or more and less than 8 μm. By setting the volume-based 50% particle diameter (D ₅₀ ) in the above range, a friction material having a high coefficient of friction and excellent wear resistance can be obtained.

The volume-based cumulative 50% particle size (D ₅₀ ) refers to the particle size 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 the point where the particle size distribution is obtained on a volume basis, the number of particles is counted from the smallest particle size on the cumulative curve with the total volume as 100%, and the cumulative value becomes 50%. is there. Similarly, for the volume-based cumulative 90% particle diameter (D ₉₀ ), the number of particles is counted from the smallest particle size in the cumulative curve with the total product of the obtained particle size distribution as 100%, and the cumulative value is 90. Indicates the particle size of the point that becomes%.

The volume-based cumulative 90% particle size (D ₉₀ ) of mica is preferably less than 30 μm, more preferably less than 20 μm, and even more preferably less than 15 μm. By setting D ₉₀ in the above range, the number of coarse particles can be reduced, and the friction characteristics of the friction material can be further improved. The lower limit of the volume-based cumulative 90% particle diameter (D ₉₀ ) of mica is not particularly limited, but may be, for example, 0.1 μm.

The specific surface area of the titanium salt compound is preferably ^{1m 2} / ^g~10m 2 / g, more preferably from ^{3m 2} / ^g~10m 2 / g, more preferably ^{7m 2} / ^g~9m 2 / g Is. The specific surface area can be measured according to JIS Z8830.

As the above-mentioned mica, there are natural mica calculated naturally and synthetic mica artificially synthesized, and both can be used, but natural mica is preferable from the viewpoint of wear of the mating material (rotor). Natural mica includes muscovite (muscovite), phlogopite (phlogopite), biotite (biotite), and suzolite, depending on the components contained, and one of these is used alone or in combination of two or more. be able to. Muscovite is preferable from the viewpoint of wear resistance. Further, the mica may be surface-treated with a coupling agent.

The content of mica in the friction material composition is preferably 0.1% by mass to 15% by mass, and 1% by mass to 10% by mass, based on 100% by mass of the total amount of the friction material composition. Is more preferable. By setting the content of mica within the above range, even more excellent friction characteristics can be obtained.

(Thermosetting resin)
The thermosetting resin is used as a binder that imparts strength by being integrated with a titanate compound, mica, or the like. Therefore, any known thermosetting resin used as a binder can be appropriately selected and used.

Examples of the thermosetting resin include phenolic resins; elastomer-dispersed phenolic resins such as acrylic elastomer-dispersed phenolic resins and silicone elastomer-dispersed phenolic resins; acrylic-modified phenolic resins, silicone-modified phenolic resins, cashew-modified phenolic resins, and epoxy-modified phenolic resins. Modified phenolic resins such as alkylbenzene-modified phenolic resins; formaldehyde resins; melamine resins; epoxy resins; acrylic resins; aromatic polyester resins; urea resins and the like. One of these can be used alone or in combination of two or more. Among these, phenolic resin (straight phenolic resin) and modified phenolic resin are preferable from the viewpoint of further improving heat resistance, moldability, and frictional properties.

The content of the thermosetting resin in the friction material composition is preferably 5% by mass to 20% by mass with respect to 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 binder is filled in the gaps between the compounding materials, and even more excellent friction characteristics can be obtained.

(Other materials)
In addition to the titanate compound, mica, and thermosetting resin, other materials can be added to the friction material composition of the present invention, if necessary. Examples of other materials include the following fiber base materials, friction adjusting materials, and the like.

As the fiber base material, aromatic polyamide (aramid) fiber, fibrillated aramid fiber, acrylic fiber (monopolymer or copolymer fiber mainly made of acrylic nitrile), fibrillated acrylic fiber, cellulose fiber, fibrillated Organic fibers such as cellulose fibers and phenolic resin fibers; mainly composed of metals such as aluminum, iron, zinc, tin, titanium, nickel, magnesium, silicon and other metals other than copper and copper alloys, fibers in alloy form, and metals such as cast iron fibers. Straight-shaped or curled-shaped metal fibers; glass fibers, rock wool, ceramic fibers, biodegradable ceramic fibers, biodegradable mineral fibers, biosoluble fibers (SiO ₂ -CaO-SrO-based fibers, etc.), wallast Inorganic fibers other than titanate fibers such as night fibers, silicate fibers and mineral fibers; flame resistant fibers, PAN-based carbon fibers, pitch-based carbon fibers, carbon-based fibers such as activated carbon fibers and the like can be mentioned. One of these may be used alone, or two or more thereof may be used in combination.

As the friction adjusting material, unsulfated or sulphurized rubber powder such as tire rubber, acrylic rubber, isoprene rubber, NBR (nitrile butadiene rubber), SBR (styrene butadiene rubber), chlorinated butyl rubber, butyl rubber, silicone rubber; cashew dust, Organic fillers such as melamine dust, rubber-coated cashew dust; inorganic powders such as calcium carbonate, sodium carbonate, lithium carbonate, calcium hydroxide (sulfide), vermiculite, clay, talc, dolomite, chromate, mulite; aluminum, zinc, iron Inorganic fillers such as copper and metals other than copper alloys such as tin or metal powders in alloy form; silicon carbide (silicon carbide), titanium oxide, alumina (aluminum oxide), silica (silicon dioxide), magnesia (oxidation) Grinding materials such as magnesium), zirconia (zinc oxide), zirconium silicate, chromium oxide, iron oxide (triiron tetroxide, etc.), chromate, quartz, etc .; 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, solid lubricants such as polytetrafluoroethylene (PTFE) and the like. One of these may be used alone, or two or more thereof may be used in combination.

The content of other materials in the friction material composition is preferably 20% by mass to 93.9% by mass with respect to 100% by mass of the total amount of the friction material composition.

(Manufacturing method of friction material composition)
In the friction material composition of the present invention, each component is mixed by a mixer such as (1) Reedige mixer (“Reidigue” is a registered trademark), a pressurized kneader, and an Erich mixer (“Eirich” is a registered trademark). Method; (2) It can be produced by a method of preparing a granulated product of a desired component and, if necessary, mixing other components using a mixer such as a Reedige mixer, a pressurized kneader, or an Erich mixer. it can.

The content of each component of the friction material composition of the present invention can be appropriately selected depending on the desired friction characteristics, and can be produced by the above-mentioned production method.

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

<Friction material and friction member>
In the present invention, the friction material composition is tentatively molded at room temperature (20 ° C.), and the obtained tentatively molded product is heat-press molded (molding pressure 10 MPa to 40 MPa, molding temperature 150 ° C. to 200 ° C.). If necessary, the obtained molded product is heat-treated (held at 150 ° C. to 220 ° C. for 1 hour to 12 hours) in a heating furnace, and then the molded product is machined and polished to give a predetermined value. A friction material having a shape can be manufactured.

The friction material of the present invention is used as a friction member formed by forming the friction material as a friction surface. Examples of the friction member that can be formed by using the friction material include (1) a structure consisting of only the friction material, (2) a base material such as a back metal, and a book provided on the base material to provide a friction surface. Examples thereof include a configuration having the friction material of the present invention.

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

The friction material usually has a large number of fine pores formed inside, which serves as an escape route for decomposition products (gas and liquid matter) at high temperatures to prevent deterioration of friction characteristics and reduce the rigidity of the friction material for attenuation. The occurrence of squeal is prevented by improving the property. In a normal friction material, the compounding and molding conditions of the material are controlled so that the porosity is preferably 5% to 30%, more preferably 10% to 25%.

Since the friction member of the present invention is composed of the friction material composition of the present invention, the friction coefficient is high and the abrasion resistance is excellent even when the copper component is not contained or the content of the copper component is reduced. ing. Therefore, the friction member of the present invention can be suitably used for various vehicles and brake systems in general such as disc pads, brake linings, and clutch facings that constitute braking devices for industrial machines and the like.

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 appropriately modified and implemented without changing the gist thereof.

The titanate compounds used in Examples and Comparative Examples are shown in Table 1, mica is shown in Table 2, and the powder properties are evaluated as follows.

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

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

Specifically, the particle size at a volume-based cumulative 50% in the particle size distribution measured by the laser diffraction type particle size distribution measuring device, that is, D ₅₀ (median diameter) was determined. The particle size at a volume-based cumulative 90% in the particle size distribution measured by the laser diffraction type particle size distribution measuring device, that is, D ₉₀ was determined.

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

(Alkali metal ion elution rate)
The mass (X) of the test sample was measured, then the test sample was added to distilled water to prepare a 1% by mass slurry, stirred at 80 ° C. for 4 hours, and then the solid content was removed with a membrane filter having a pore size of 0.2 μm. , An extract was obtained. The alkali metal (Y) of the obtained extract was measured by an ion chromatograph (manufactured by Dionex, product number "ICS-1100"). Next, using the values of (X) and (Y) above, the alkali metal ion elution rate (mass%) was calculated based on the formula [(Y) / (X)] × 100.

<Manufacturing of friction members>
In Examples 1 to 5 and Comparative Examples 1 to 5, the materials were blended according to the blending ratios according to Table 3, and mixed with an Erich mixer. The obtained mixture was pressed at room temperature (20 ° C.) at a pressure of 0.5 MPa for 5 seconds to prepare a temporary molded product. The above-mentioned temporary molded body is fitted into the cavity of the heat-molding mold heated to 150 ° C., and the back plate (material: steel) coated with the adhesive is placed on the cavity, and the pressure is 300 MPa at 30 MPa. Pressurized for seconds. It was measured from the start of pressurization, and degassing was performed 5 times within 5 to 60 seconds. The obtained member was placed in a constant temperature dryer heated to 210 ° C. and held for 3 hours to be completely cured to obtain a friction member.

The "phenol resin" in Table 3 is a novolak-type phenol resin powder containing hexamethylenetetramine, and the "zyrosine silicate" is zirconium silicate having a volume standard 50% particle diameter (D ₅₀ ) of 1.1 μm, and "barium sulfate". Is barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd., "barium sulfate MBH-100") having a volume standard of 50% particle diameter (D ₅₀ ) of 1.6 μm, and "rock wool" is rock wool having an average fiber length of 125 μm. ..

<Evaluation of friction members>
The surface (friction surface) of the friction member produced above is polished by 1.0 mm, a brake effectiveness test is performed based on JASO C406, and the average friction coefficient, pad wear amount (friction material wear amount) and rotor wear amount (counterpart material) are performed. Amount of wear) was calculated. As the rotor, a cast iron rotor belonging to the A type in the ASTM standard was used. The results are shown in Table 3.

From Table 3, it can be seen that the friction materials of Examples 1 to 5 containing the fine particle mica have a smaller amount of wear (excellent wear resistance) than the friction materials of Comparative Examples 1 to 5. In particular, the friction materials of Examples 1, 2 and 5 containing the titanate compound having a plate-like particle shape not only have a reduced amount of wear but also a higher friction coefficient. I understand.

Claims (11)

Friction material composition
Contains non-fibrous titanate compound, mica and thermosetting resin
The volume-based 50% particle diameter (D ₅₀ ) of the mica is less than 10 μm.
A friction material composition, wherein the content of the copper component is less than 0.5% by mass as a copper element in a total amount of 100% by mass of the friction material composition. The friction material composition according to claim 1, wherein the titanate compound is at least one of a titanate compound having a tunnel-shaped crystal structure and a titanate compound having a layered crystal structure. Titanate compounds of the tunnel-like crystal _structure, wherein, A is one or more alkali metals except Li, n is the number of 2 to 11] _{A 2 Ti n O (2n +} 1) is, The friction material composition according to claim 2. 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, Mn, x is 0.5 to 1.0, y is 0.25 to 1.0], A _{0.5 to 0 .7} Li _0.27 Ti _1.73 O _{3.85 to 3.95} [In the formula, 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 according to} claim 2, wherein A is at least one selected from the group consisting of one or more alkali metals excluding Li. Friction material composition. The friction according to any one of claims 2 to 4, wherein the titanate compound having a tunnel-like crystal structure is particles having a plurality of convex shapes, plate-like particles, columnar particles, or spherical particles. Material composition. The friction material composition according to any one of claims 2 to 5, wherein the titanate compound having a layered crystal structure is plate-like particles. The friction material composition according to any one of claims 1 to 6, wherein the volume-based 50% particle diameter (D ₅₀ ) of the titanate compound is 0.1 μm to 100 μm. Any one of claims 1 to 7, wherein the content of the titanate compound is 1% by mass to 40% by mass with respect to 100% by mass of the total amount of the friction material composition. The friction material composition according to the item. Any one of claims 1 to 8, wherein the content of the mica is 0.1% by mass to 15% by mass with respect to 100% by mass of the total amount of the friction material composition. The friction material composition according to. A friction material, which is a molded product of the friction material composition according to any one of claims 1 to 9. A friction member comprising the friction material according to claim 10.