JPWO2020121504A1 - Friction member, friction material composition for underlaying material and underlaying material - Google Patents

Abstract

A friction member having an upholstery material, an underlaying material, and a back plate in this order, and the underlaying material does not contain copper, or even if it contains copper, the copper content is less than 0.5% by mass as a copper element. The present invention relates to a friction member, wherein the underlaying material is formed by blending two or more kinds of carbonaceous particles having different average particle diameters (D50).

Description

The present invention relates to a friction member, a friction material composition for an underlaying material, a method for producing a friction material composition for an underlaying material, and an underlaying material.

As a disc brake pad, which is a friction member for braking that is attached to two-wheeled vehicles, four-wheeled vehicles, etc., a friction member in which an upholstery material is fixed to one surface of a back plate made of metal such as iron via an underlaying material. Is used.
Disc brake pads are used by painting the sides of the back plate and friction material with paint in order to suppress the generation of rust caused by the adhesion of moisture during use.
There is a powder coating method as one of the coating methods for disc brake pads. In the powder coating method, the disc brake pad is charged, the powder paint is electrically adhered to the surface, and then heated in a baking furnace to melt the powder paint to form a coating film on the surface of the disc brake pad. (See, for example, Patent Document 1).

In recent years, it has been suggested that copper used for friction materials scatters as abrasion powder for brakes and contaminates rivers, lakes, oceans, etc., limiting the amount of copper used in friction materials in Japan and other countries. The movement to do is increasing. However, copper has high conductivity among the materials constituting the friction material, and if the use of copper is restricted, the conductivity of the disc brake pad decreases. The decrease in conductivity causes a decrease in the amount of electrostatic adhesion of the paint during powder coating, and as a result, the amount of film formation in the coating is reduced, making it difficult to obtain a good coating film having corrosion resistance.

As a means for obtaining a good coating film on a friction material containing no copper, a method of increasing the conductivity of the friction material by adding a specific graphite to the friction material composition or increasing the amount of graphite has been proposed. For example, see Patent Document 2). However, if the amount of graphite in the friction material is increased, the lubricating action of graphite is excessively increased, causing a problem that the friction coefficient is lowered. Therefore, there is a limit to the improvement of conductivity by increasing the amount of graphite.

Further, as a method for increasing the conductivity of the surface of the friction material, a method for manufacturing a friction material is proposed in which a pre-coating process of applying a carbon-based particle dispersion liquid to a part or all of the powder-coated surface is added before the coating process. (See Patent Document 3).

Japanese Unexamined Patent Publication No. 2003-166574 International Publication 2014/147807 JP-A-2018-146106

According to the method of Patent Document 3, a disc in which the electrostatic adhesion amount of the paint at the time of powder coating is sufficient and the film formation of the paint is good without increasing the content of graphite in the friction material composition. Brake pads can be provided. However, from the viewpoint of the productivity of disc brake pads, a technique for improving conductivity and powder coatability while having good frictional performance by a simpler method is desired.

The present invention has been made in view of the above circumstances, and is a friction member having an upholstery material, an underlaying material, and a back plate in this order, and the underlaying material does not contain copper, or even if it contains copper. A friction member having good friction performance and excellent powder coatability even when the content is less than 0.5% by mass as a copper element, a friction material composition for an underlaying material used for the friction member, and a friction material composition for an underlaying material used for the friction member. It is an object of the present invention to provide the manufacturing method and the underlaying material.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following invention, and have completed the present invention.
That is, the present invention relates to the following [1] to [15].
[1] A friction member having an upholstery material, an underlaying material, and a back plate in this order.
The underlaying material does not contain copper, or even if it contains copper, the copper content is less than 0.5% by mass as a copper element.
Moreover, the friction member is formed by blending two or more kinds of carbonaceous particles having different average particle diameters (D _{50) in the underlaying material.}
[2] Of the two or more types of carbonaceous particles, at least one type of carbonic particles is _{carbonaceous particles (A) having an average particle diameter (D 50} ) of 8 to 60 μm, and at least another one. The friction member according to the above [1], wherein the carbonaceous particles of the seed are carbonic _{particles (B) having an average particle diameter (D 50) of 7 μm or less.}
[3] The blending amount of the carbonic particles (A) is 1 to 11 parts by mass with respect to 100 parts by mass of the underlaying material, and the blending amount of the carbonic particles (B) is 100 parts by mass of the underlaying material. The friction member according to the above [1] or [2], which is 0.1 to 10 parts by mass with respect to the parts.
[4] The friction member according to any one of the above [1] to [3], wherein the two or more kinds of carbonaceous particles are graphite.
[5] Two or more kinds of carbonaceous particles that do not contain copper, or even if they contain copper, the content of copper is less than 0.5% by mass as a copper element and the average particle size (D _{50) is different.} Friction material composition for underlaying material, which is made by blending.
[6] Of the two or more types of carbonaceous particles, at least one type of carbonic particles is _{carbonaceous particles (A) having an average particle diameter (D 50} ) of 8 to 60 μm, and at least another one. The friction material composition for an underlaying material according to the above [5], wherein the carbonaceous particles of the seed are carbonic _{particles (B) having an average particle diameter (D 50) of 7 μm or less.}
[7] The blending amount of the carbonic particles (A) is 1 to 11 parts by mass with respect to 100 parts by mass of the friction material composition for the underlaying material, and the blending amount of the carbonic particles (B) is The friction material composition for an underlaying material according to the above [6], which is 0.1 to 10 parts by mass with respect to 100 parts by mass of the friction material composition for an underlaying material.
[8] The friction material composition for an underlaying material according to any one of the above [5] to [7], wherein the two or more kinds of carbonaceous particles are graphite.
[9] An underlaying material obtained by molding the friction material composition for an underlaying material according to any one of the above [5] to [8].
[10] A method for producing a friction material composition for an underlaying material according to any one of the above [5] to [8].
A method for producing a friction material composition for an underlaying material, which comprises two or more kinds of carbonaceous particles having different average particle diameters (D _50).
[11] Copper is not contained, or even if it is contained, the content of copper is less than 0.5% by mass as a copper element, and carbonaceous particles are contained, and the carbonaceous particles are based on the volume. A friction material composition for an underlaying material, which has two or more peaks in a particle size distribution curve showing a frequency distribution.
[12] The above-mentioned [11], wherein the two or more peaks include a first peak having a maximum in the range of 8 to 60 μm and a second peak having a maximum in the range of 7 μm or less. Friction material composition for underlayment material.
[13] The friction material composition for an underlaying material according to the above [11] or [12], wherein the carbonaceous particles are graphite.
[14] An underlaying material obtained by molding the friction material composition for an underlaying material according to any one of the above [11] to [13].
[15] A friction member having an upholstery material, an underlaying material according to the above [14], and a back plate in this order.

According to the present invention, it is a friction member having an upholstery material, an underlaying material and a back plate in this order, and the underlaying material does not contain copper, or even if the underlaying material contains copper, the copper content is 0.5 as a copper element. Provided are a friction member having good friction performance and excellent powder coatability even in a composition of less than mass%, a friction material composition for an underlaying material used for the friction member, a method for producing the same, and an underlaying material. can do.

It is a schematic view (top view) which shows the disc brake pad. It is a schematic diagram of the AA cross section in FIG.

Hereinafter, the present invention will be described in detail. However, in the following embodiments, the components are not essential unless otherwise specified. The same applies to the numerical values and their ranges, and does not limit the present invention.
In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, in the present specification, the content of each component in the underlaying material or the friction material composition for the underlaying material is the underlaying material or the underlaying material when a plurality of substances corresponding to the respective components are present, unless otherwise specified. It means the total content of the plurality of kinds of substances present in the friction material composition for materials.
The present invention also includes aspects in which the items described in the present specification are arbitrarily combined.

[Friction member]
The friction member of this embodiment is
A friction member having an upholstery material, an underlaying material, and a back plate in this order.
The underlaying material does not contain copper, or even if it contains copper, the copper content is less than 0.5% by mass as a copper element.
Moreover, the underlaying material is a friction member formed by blending two or more kinds of carbonaceous particles having different _{average particle diameters (D 50).}

Explaining the configuration of the friction member of the present embodiment with reference to FIGS. 1 and 2, the friction member 4 of the present embodiment has an upholstery member 1, an underlayment member 2, and a back plate 3 in this order.
Here, the upholstery member 1 is a friction material which is a friction surface of the friction member 4, and the underlay material 2 is interposed between the upholstery material 1 which is a friction surface of the friction member 4 and the back plate 3. A layer intended to improve shear strength and crack resistance. However, the friction member of the present embodiment is not limited to the configurations of FIGS. 1 and 2, and for example, a surface for enhancing the adhesive effect of the back plate 3 between the back plate 3 and the underlaying material 2. It may be a friction member having a primer layer interposed therebetween for the purpose of modification, or may be a friction member having a shim on the side of the back plate 3 opposite to the side having the underlaying material 2. The shim is a spacer used to improve the vibration damping property of the friction member.
Hereinafter, each member constituting the friction member of the present embodiment will be described.

<Underlay material>
The underlaying material included in the friction member of the present embodiment is
Contains two or more types of carbonaceous particles that do not contain copper, or even if they do, the copper content is less than 0.5% by mass as a copper element and the average particle size (D _{50) is different.} It is made up of.
The underlaying material contained in the friction member of the present embodiment does not contain copper by containing the above-mentioned carbonaceous particles, or even if it contains copper, the content of copper is less than 0.5% by mass as a copper element. In terms of composition, good powder coating is possible while having excellent frictional performance. The cause is not clear, but it is thought to be as follows.
Since carbonaceous particles typified by graphite are themselves conductors, the larger the particle size, the easier it is for a conductive path to be formed. On the other hand, as the particle size of the carbonaceous particles becomes larger, the formed conductive path becomes more local, and the homogeneity of the conductivity of the friction material as a whole tends to be insufficient. On the other hand, in the underlaying material of the friction member of the present embodiment, the conductive path is appropriately formed by containing the relatively large size carbonaceous particles at a high frequency, and the underlaying material is larger than the carbonic particles. Frequent inclusion of relatively small size carbonaceous particles can improve the conductivity of the entire friction material while maintaining homogeneity, which allows good powder without the addition of large amounts of graphite. It is presumed that painting became possible.

(Carbonate particles)
The number of types of carbonaceous particles to be blended may be two or more having different _{average particle diameters (D 50), and is preferably two.} However, depending on the desired performance, the number may be 3 or more, 4 or more, 6 or less, or 5 or less.
In this embodiment, the average particle size of the carbonaceous particles can be measured by a laser diffraction scattering method based on the Mie scattering theory. Specifically, it can be measured by creating a particle size distribution of carbonaceous particles on a volume basis with a laser diffraction / scattering type particle size distribution measuring device and using the median diameter as the average particle size. As the measurement sample, carbonaceous particles added to ion-exchanged water can be dispersed by ultrasonic waves of 50 to 300 W for 1 to 10 minutes. In order to enhance the dispersibility of the carbonaceous particles, a surfactant (for example, "Tween-20" manufactured by Tokyo Chemical Industry Co., Ltd.) can be added in an amount of 0.5 to 5% by mass based on 100% by mass of ion-exchanged water. As the laser diffraction / scattering type particle size distribution measuring device, "LA-950" manufactured by HORIBA, Ltd. or the like can be used.

Of the two or more types of carbonaceous particles, at least one type of carbonic particles is preferably carbonaceous particles (A) having an _{average particle diameter (D 50) of 8 to 60 μm.} The average particle size (D ₅₀ ) of the carbonaceous particles (A) is preferably 10 to 55 μm, more preferably 20 to 50 μm, and even more preferably 30 to 45 μm from the viewpoint of improving the wear resistance of the underlaying material. The average particle size (D ₅₀ ) of the carbonaceous particles (A) is preferably 8 to 45 μm, more preferably 9 to 30 μm, and even more preferably 10 to 25 μm from the viewpoint of imparting conductivity.

Further, among the two or more kinds of carbonaceous particles, at least one kind of carbonic particles is preferably carbonaceous particles (B) having an _{average particle diameter (D 50) of 7 μm or less.} The average particle size (D ₅₀ ) of the carbonaceous particles (B) is more preferably 6 μm or less, further preferably 5 μm or less, and particularly preferably 4 μm or less. The average particle size (D ₅₀ ) of the carbonaceous particles (B) may be 0.1 μm or more, 0.5 μm or more, or 1 μm or more.

As the two or more kinds of carbonaceous particles, it is preferable to blend the carbonic particles (A) and the carbonic particles (B). _{At that time, the difference between the average particle size (D 50} ) of the carbonaceous particles (A) and the average particle size (D ₅₀ ) of the carbonic particles (B) is 1 μm from the viewpoint of imparting conductivity to the underlay material. The above is preferable, 3 μm or more is more preferable, and 5 μm or more is further preferable. Further, from the same viewpoint, it may be 10 μm or more, 20 μm or more, or 30 μm or more.
Further, the above difference is preferably 50 μm or less, more preferably 45 μm or less, still more preferably 40 μm or less, from the viewpoint of preventing segregation of the carbonic particles in the underlaying material. Further, from the same viewpoint, it may be 30 μm or less, 20 μm or less, or 10 μm or less.

In the underlaying material of the friction member of the present embodiment, carbonaceous particles other than the carbonic particles (A) and the carbonic particles (B) may be blended as the carbonaceous particles, but may not be blended. ..

The blending amount of the carbonaceous particles (A) in the underlaying material is preferably 1 to 11 parts by mass, more preferably 2 to 10 parts by mass, and even more preferably 3 to 9 parts by mass with respect to 100 parts by mass of the underlaying material.
The blending amount of the carbonaceous particles (B) in the underlaying material is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and 0.5 to 5 parts by mass with respect to 100 parts by mass of the underlaying material. Parts by mass are even more preferred.
The total amount of carbonaceous particles in the underlayment is preferably 3 to 11.5 parts by mass, more preferably 5 to 11 parts by mass, and further 7 to 10.5 parts by mass with respect to 100 parts by mass of the underlay material. Preferably, 7.5 to 10 parts by mass is particularly preferable.

In the present embodiment, examples of the carbonaceous particles include carbon black, coke, graphite, expanded graphite, expanded graphite, easy graphite, difficult graphite, and the like, and among these, it is said that they are excellent in abrasion resistance and conductivity. From the viewpoint, graphite is preferable.
The type of graphite is not particularly limited, and may be artificial graphite, natural graphite, or a combination of artificial graphite and natural graphite.
The shape of the carbonaceous particles is not particularly limited, and examples thereof include spherical, plate-like, columnar, scaly, fibrous, amorphous, and structural structures, and carbonaceous particles having one of these shapes. The particles and carbonaceous particles having a shape different from the above one shape may be mixed and used. Among these, the shape of the carbonaceous particles is preferably spherical, indefinite, or fibrous from the viewpoint of imparting conductivity.

The underlaying material contained in the friction member of the present embodiment is further selected from the group consisting of a binder, an organic filler, an inorganic filler other than carbonaceous particles (hereinafter, also simply referred to as “inorganic filler”), and a fiber base material. It is preferable to contain one or more kinds of the above.

(Binder)
The binder has a function of binding and integrating carbonaceous particles, an organic filler, an inorganic filler, a fiber base material, and the like to give a predetermined shape and strength.
The binder is not particularly limited, and a binder usually used for the underlayment can be used.
As the binder, for example, a thermosetting resin is preferably used.
Examples of the thermosetting resin include phenol resin, epoxy resin, polyimide resin, melamine resin and the like. The phenol resin may be an unmodified phenol resin, a modified phenol resin, an elastomer-dispersed phenol resin, or the like, and the modified phenol resin includes an acrylic-modified phenol resin, a silicone-modified phenol resin, a cashew-modified phenol resin, and the like. Examples thereof include epoxy-modified phenolic resins and alkylbenzene-modified phenolic resins. Examples of the elastomer-dispersed phenol resin include an acrylic elastomer-dispersed phenol resin and a silicone elastomer-dispersed phenol resin. Among these, an unmodified phenol resin, an acrylic-modified phenol resin, a silicone-modified phenol resin, and an alkylbenzene-modified phenol resin are preferable from the viewpoint of providing good heat resistance, moldability, and friction coefficient.
As the binder, one type may be used alone, or two or more types may be used in combination.

The content of the binder in the underlaying material is preferably 5 to 30 parts by mass, more preferably 7 to 25 parts by mass, further preferably 9 to 20 parts by mass, and 10 to 15 parts by mass with respect to 100 parts by mass of the underlaying material. Part is particularly preferable. By setting the content of the binder within the above range, the strength of the underlaying material can be maintained, and deterioration of vibration damping properties such as squealing due to an increase in elastic modulus can be further suppressed.

(Organic filler)
The organic filler can exhibit a function as a friction modifier for improving vibration damping property, wear resistance and the like. Here, in the present embodiment, the organic filler does not include those having a fiber shape (for example, organic fibers described later). As the organic filler, one type may be used alone, or two or more types may be used in combination.

The organic filler may contain an organic filler such as cashew particles, rubber, and melamine dust. Among these, cashew particles and rubber are preferable from the viewpoint of improving the stability and wear resistance of the friction coefficient and suppressing squeal. Cashew particles and rubber may be used in combination, or cashew particles coated with rubber may be used.
As the organic filler, one type may be used alone, or two or more types may be used in combination.

Cashew particles are obtained by crushing hardened cashew nut shell oil, and are also commonly referred to as cashew dust.
Cashew particles are generally classified into brown-based, brown-black-based, black-based, and the like according to the type of curing agent used in the curing reaction. By adjusting the molecular weight and the like of the cashew particles, it is possible to easily control the heat resistance, the sound vibration property, and the film forming property on the rotor which is the mating material.
From the viewpoint of dispersibility, the average particle size of cashew particles is preferably 850 μm or less, more preferably 750 μm or less, and even more preferably 600 μm or less. The lower limit of the average particle size of the cashew particles is not particularly limited, and may be 200 μm or more, 300 μm or more, or 400 μm or more.

When the underlaying material contains cashew particles, the content thereof is preferably 0.5 to 10 parts by mass, more preferably 1 to 7 parts by mass, and further 2 to 5 parts by mass with respect to 100 parts by mass of the underlaying material. preferable. When the content of cashew particles is not less than the above lower limit value, appropriate flexibility can be imparted to the underlaying material, so that the sound vibration property tends to be improved. There is a tendency to suppress a decrease in crack resistance.

As the rubber, rubber usually used for the underlaying material can be used, and examples thereof include natural rubber and synthetic rubber. Examples of the synthetic rubber include acrylonitrile-butadiene rubber (NBR), acrylic rubber, isoprene rubber, polybutadiene rubber (BR), styrene butadiene rubber (SBR), silicone rubber, and crushed powder of tire tread rubber. Among these, pulverized powder of acrylonitrile-butadiene rubber (NBR) and tire tread rubber is preferable from the viewpoint of balance between heat resistance, flexibility and manufacturing cost.

When the underlaying material contains rubber, the content thereof is preferably 0.5 to 10 parts by mass, more preferably 1 to 7 parts by mass, still more preferably 2 to 5 parts by mass with respect to 100 parts by mass of the underlaying material. .. When the rubber content is within the above range, it tends to be possible to avoid increasing the elastic modulus of the underlaying material and deteriorating the vibration damping property such as squeal, and also the deterioration of heat resistance and heat history. There is a tendency that the decrease in strength due to the above can be avoided.

When the underlaying material contains an organic filler, the total content thereof is preferably 1 to 15 parts by mass, more preferably 3 to 10 parts by mass, and further 5 to 8 parts by mass with respect to 100 parts by mass of the underlaying material. preferable. When the total content of the organic filler is within the above range, the elastic modulus of the underlaying material tends to be high, and deterioration of vibration damping properties such as squealing and deterioration of wear resistance tend to be avoided. There is a tendency that deterioration of heat resistance and decrease in strength due to heat history can be avoided.

(Inorganic filler)
The inorganic filler can exhibit a function as a friction modifier for avoiding deterioration of heat resistance, wear resistance, stability of friction coefficient, etc. of the underlaying material. Here, in the present embodiment, the inorganic filler does not include those having a fiber shape (for example, inorganic fibers described later).
As the inorganic filler, one kind may be used alone, or two or more kinds may be used in combination.

The inorganic filler is not particularly limited, and an inorganic filler usually used for the underlaying material can be used. Examples of the inorganic filler include metal sulfides such as antimony trisulfide, tin sulfide, molybdenum disulfide, bismuth sulfide, and zinc sulfide; titanium such as potassium titanate, lithium potassium titanate, sodium titanate, and magnesium potassium titanate. Acids; mica, calcium hydroxide, calcium oxide, sodium carbonate, calcium carbonate, magnesium carbonate, barium sulfate, dolomite, vermiculite, calcium sulfate, granular potassium titanate, talc, clay, zeolite, chromate, zirconium oxide, titanium oxide, It contains magnesium oxide, triiron tetroxide, zinc oxide, α-alumina, γ-alumina; iron powder, cast iron powder, aluminum powder, nickel powder, tin powder, zinc powder, and at least one of the above metals. Examples include metal powders such as alloy powders. Among these, calcium hydroxide and barium sulfate are preferable.

When the underlaying material contains calcium hydroxide, the content thereof is preferably 0.2 to 7 parts by mass, more preferably 0.5 to 5 parts by mass, and 1 to 3 parts by mass with respect to 100 parts by mass of the underlaying material. The portion is more preferable.
When the underlaying material contains barium sulfate, the content thereof is preferably 10 to 60 parts by mass, more preferably 30 to 55 parts by mass, still more preferably 40 to 50 parts by mass with respect to 100 parts by mass of the underlaying material.
When the underlaying material contains an inorganic filler, the total content thereof is preferably 20 to 65 parts by mass, more preferably 30 to 60 parts by mass, and further preferably 45 to 55 parts by mass with respect to 100 parts by mass of the underlaying material. preferable.

(Fiber base material)
The underlay material preferably further contains a fiber base material.
The fiber base material exhibits a reinforcing action in the underlaying material.
Examples of the fiber base material include organic fibers and inorganic fibers.
As the fiber base material, one type may be used alone, or two or more types may be used in combination.

-Organic fiber-
The organic fiber is a fibrous material containing an organic substance as a main component.
Examples of the organic fiber include hemp, cotton, aramid fiber, cellulose fiber, acrylic fiber and the like. Among these, aramid fiber is preferable from the viewpoint of heat resistance.
When the underlaying material contains organic fibers, the content thereof is preferably 0.5 to 10 parts by mass, more preferably 1 to 7 parts by mass, and further 2 to 5 parts by mass with respect to 100 parts by mass of the underlaying material. preferable. When the content of the organic fiber is at least the above lower limit value, good shear strength, crack resistance and wear resistance tend to be exhibited, and when it is at least the above upper limit value, the organic fiber and other materials in the underlaying material are exhibited. Deterioration of shear strength and crack resistance due to uneven distribution can be effectively suppressed.

-Inorganic fiber-
The inorganic fiber is a fibrous material containing an inorganic substance other than a metal and a metal alloy as a main component, and can exhibit the effect of improving the mechanical strength and wear resistance of the underlaying material.
Examples of the inorganic fiber include mineral fiber, glass fiber, fibrous wollastonite, metal fiber, carbon fiber, ceramic fiber, biodegradable ceramic fiber, rock wool, potassium titanate fiber, silica alumina fiber, flame resistant fiber and the like. Be done. Among these, mineral fiber and glass fiber are preferable.

The mineral fiber is an artificial inorganic fiber melt-spun mainly from blast furnace slag such as slag wool, basalt such as basalt fiber, and other natural rocks. Examples of the mineral fiber include _{a mineral fiber containing SiO 2} , Al ₂ O ₃ , CaO, MgO, FeO, Na ₂ O and the like, or a mineral fiber containing one or more of these compounds. As the mineral fiber, a mineral fiber containing an aluminum element is preferable, _{a mineral fiber containing Al 2} O ₃ is more preferable, and a mineral fiber containing Al ₂ O ₃ and SiO ₂ is further preferable.
The average fiber length of the mineral fiber is preferably 500 μm or less, more preferably 400 μm or less, still more preferably 340 μm or less, from the viewpoint of suppressing a decrease in shear strength. Further, the average fiber length of the mineral fiber may be, for example, 100 μm or more, or 120 μm or more.
The average fiber diameter (diameter) of the mineral fiber is not particularly limited, but is usually 1 to 20 μm, and may be 2 to 15 μm.

The mineral fiber is preferably biosoluble from the viewpoint of harm to the human body. The biosoluble mineral fiber referred to here is a mineral fiber having a characteristic that even if it is taken into the human body, it is partially decomposed in a short time and excreted from the body. Specifically, the chemical composition is such that the total amount of alkali oxides and alkaline earth oxides (total amount of oxides of sodium, potassium, calcium, magnesium and barium) is 18% by mass or more, and (a) short-term inhalation. In-vivo endurance test by exposure shows that the half-life of fibers over 20 μm in length is less than 10 days, and (b) in-vivo endurance test by short-term intratracheal injection shows half-life of fibers over 20 μm in length. Is less than 40 days, (c) no significant carcinogenicity in the intraperitoneal administration test, or (d) no pathological findings or tumorigenesis associated with carcinogenicity in the long-term inhalation exposure test. A fiber satisfying any of the above conditions (see Nota Q (exclusion of carcinogenicity) of EU Directive 97/69 / EC) is shown. Examples of such biodegradable mineral fibers include SiO _2- Al ₂ O _3- CaO-MgO. -FeO (-K ₂ O-Na ₂ O) -based fibers and the like can be mentioned, _{and at least two types selected from SiO 2} , Al ₂ O ₃ , CaO, MgO, FeO, K ₂ O, Na ₂ O and the like are optional. Examples thereof include mineral fibers contained in the combination of.

When the underlay material contains mineral fibers, the content thereof is preferably 5 to 30 parts by mass, more preferably 10 to 25 parts by mass, and even more preferably 13 to 20 parts by mass with respect to 100 parts by mass of the underlay material.
When the underlaying material contains glass fiber, the content thereof is preferably 1 to 25 parts by mass, more preferably 5 to 20 parts by mass, and further preferably 7 to 15 parts by mass with respect to 100 parts by mass of the underlaying material.
When the underlay material contains inorganic fibers, the total content thereof is preferably 10 to 50 parts by mass, more preferably 15 to 40 parts by mass, still more preferably 20 to 30 parts by mass with respect to 100 parts by mass of the underlay material. .. When the total content of the inorganic fibers is in the above range, the mechanical strength and wear resistance of the underlaying material can be further improved.

(Other materials)
The underlaying material may be composed of only the above-mentioned components, and may contain other components other than the above-mentioned components, if necessary.

(Copper content)
The underlaying material does not contain copper, or even if it contains copper, the copper content is less than 0.5% by mass as a copper element, preferably 0.2% by mass or less, and more preferably 0.05% by mass or less. preferable. When the copper content is in the above range, it can be prevented from causing pollution of rivers and the like even if it is released as abrasion powder into the environment. The copper content indicates the content of copper element (Cu) contained in fibrous or powdery copper, copper alloys and copper compounds in the entire underlay material.

(Iron content)
The underlay material preferably does not contain an iron-based metal, but when it contains an iron-based metal, the content of the iron-based metal in the underlay material is preferably less than 0.5% by mass as an iron element, and is 0. .2% by mass or less is more preferable, and 0.05% by mass or less is further preferable. When the iron content is in the above range, the rust resistance can be made good, and the deterioration of durability due to rusting at the bonding interface with the back plate can be suppressed.

(Asbestos content)
The underlaying material is classified as NAO (Non-Asbestos-Organic) material, and is a so-called non-asbestos friction material (friction material that does not contain asbestos, or even if it contains asbestos, the content of asbestos is extremely small. Friction material). The underlay material preferably does not contain asbestos, but when it contains asbestos, the content of asbestos in the underlay material is preferably 0.2% by mass or less.

The thickness of the underlaying material is preferably 1 mm or more, more preferably 1 to 5 mm, still more preferably 1 to 4 mm. When the thickness of the underlaying material is 1 mm or more, the heat insulating effect between the upholstery material and the back plate is enhanced, and cracks and cracks in the back plate can be effectively suppressed.

The underlaying material can be produced by using the friction material composition for the underlaying material of the present embodiment described later.

<Upholstery material>
The upholstery material is formed by molding a friction material composition for an upholstery material, and is a friction material that serves as a friction surface of the friction member. The friction material composition for the upholstery material is not particularly limited, and a known friction material composition for the upholstery material can be used. Specifically, it contains an organic filler, an inorganic filler, a fiber base material and a binder, and does not contain copper, or even if it contains copper, the content of the copper is 0.5% by mass as a copper element. It is preferable to use a friction material composition for an upholstery material which is less than. As the organic filler, the inorganic filler, the fiber base material and the binder, the same ones as described in the underlaying material can be used.

<Back plate>
The back plate is usually used as a friction member in order to improve the mechanical strength of the friction member, and as a material, metal, fiber reinforced plastic or the like can be used. Examples of the back plate include iron, stainless steel, inorganic fiber reinforced plastic, carbon fiber reinforced plastic and the like. The primer layer and the adhesive layer may be those usually used for friction members such as brake shoes.

<Manufacturing method of friction member>
The friction member of the present embodiment is, for example, a friction material composition for an upholstery material and a friction material composition for an underlaying material separately, a Reedige mixer (“Redigue” is a registered trademark), a pressure kneader, and Eirich. Mix using a mixer such as a mixer (“Eich” is a registered trademark), and pre-mold the friction material composition for the upholstery material and the friction material composition for the underlayment material after mixing integrally with a molding mold. , The preformed body for the underlaying material and the preformed body for the upholstery material are superposed on one surface of the back plate, and molded in 2 to 10 minutes under the conditions of, for example, a molding temperature of 130 to 160 ° C. and a molding pressure of 20 to 50 MPa. Then, the obtained molded product is produced by, for example, heat-treating at 150 to 250 ° C. for 2 to 10 hours. Further, if necessary, painting, scorch treatment, and polishing treatment may be performed. In the above steps, the preforming step may be omitted and the mixture may be directly thermoformed.

The friction member of this embodiment is suitable for disc brake pads or drum brake linings. In addition, by performing processes such as molding, processing, and pasting the friction material composition for the upholstery material and the friction material composition for the underlaying material into the desired shape, it can also be used as a friction material for clutch facing, electromagnetic brakes, holding brakes, etc. Can be used.

[Friction material composition for underlaying material]
The friction material composition for an underlaying material of the present embodiment does not contain copper, or even if it contains copper, the content of copper is less than 0.5% by mass as a copper element, and the average particle size (D _50). ) Are two or more kinds of different carbonaceous particles.
The description of each component contained in the friction material composition for an underlaying material of the present embodiment describes the components contained in the underlaying material contained in the friction member of the present embodiment described above, except for changes in the chemical state of the curable resin and the like. Same as the description. For example, the content of each component in the underlaying material described above can be read as the content of each component in the friction material composition for the underlaying material.
The friction material composition for an underlaying material of the present embodiment can be produced by blending two or more kinds of carbonaceous particles having different _{average particle diameters (D 50) and the above-mentioned components to be blended as necessary.} ..

[Friction material composition for underlaying material of the second embodiment]
The present invention also provides a friction material composition for an underlaying material according to the following second embodiment.
The friction material composition for an underlaying material of the second embodiment does not contain copper, or even if it contains copper, the content of copper is less than 0.5% by mass as a copper element and contains carbonaceous particles. However, the carbonaceous particles have two or more peaks in the particle size distribution curve showing the frequency distribution based on the volume.
Hereinafter, the friction material composition for the underlaying material of the second embodiment will be described in detail.

<Carbonate particles>
The carbonaceous particles contained in the friction material composition for an underlaying material of the second embodiment have two or more peaks in a particle size distribution curve showing a volume-based frequency distribution.
In the present embodiment, the particle size distribution curve showing the volume-based frequency distribution of carbonaceous particles is measured by, for example, the following method.
(1) When the carbonaceous particles are in the form of powder The measurement can be performed by the same method as the average particle size of the carbonaceous particles described above.
(2) When carbonaceous particles are contained in the underlaying material A cross section formed by cutting the underlaying material is observed using a scanning electron microscope / energy-dispersed X-ray spectroscopy, and these 500 to The particle size (equivalent to a circle) of 1000 particles arbitrarily selected in a 3000-fold cross-sectional observation is measured, and a volume-based particle size distribution curve is obtained by plotting the horizontal axis as the particle size and the vertical axis as the abundance ratio of particles.
That is, in obtaining the particle size distribution curve of the carbonaceous particles in the friction material composition for the underlaying material, if the carbonic particles can be isolated, they may be measured according to the method (1) above, and if they cannot be isolated. May be measured as being contained in the underlaying material according to the method (2) above.

For carbonaceous particles, the number of peaks on the particle size distribution curve showing the volume-based frequency distribution (hereinafter, the term "peak" simply means the peak on the particle size distribution curve showing the volume-based frequency distribution) is It may be two or more, and preferably two. However, depending on the desired performance, it may be 3 or more, 4 or more, 6 or less, or 5 or less.

Any peak of the two or more peaks of the carbonaceous particles (excluding the peak on the smallest particle size side) is the first peak, and any peak on the particle size side of the first peak. The two or more peaks include a first peak having a maximum in the range of 8 to 60 μm and a second peak having a maximum in the range of 7 μm or less. It is preferable that it is a particle.

The maximum range of the first peak is preferably 10 to 55 μm, more preferably 20 to 50 μm, and even more preferably 30 to 45 μm from the viewpoint of improving the wear resistance of the underlaying material. From the viewpoint of improving conductivity, 8 to 45 μm is preferable, 9 to 30 μm is more preferable, and 10 to 25 μm is further preferable.
From the viewpoint of improving the wear resistance of the underlaying material, the maximum range of the second peak is preferably 7 μm or less, more preferably 6 μm or less, further preferably 5 μm or less, and particularly preferably 4 μm or less. Further, the maximum range of the second peak may be 0.1 μm or more, 0.5 μm or more, or 1 μm or more.

The difference between the maximum of the first peak and the maximum of the second peak is preferably 1 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more, from the viewpoint of improving conductivity. Further, from the same viewpoint, it may be 10 μm or more, 20 μm or more, or 30 μm or more.
Further, the above difference is preferably 50 μm or less, more preferably 45 μm or less, still more preferably 40 μm or less, from the viewpoint of preventing segregation of the carbonic particles in the underlaying material. Further, from the same viewpoint, it may be 30 μm or less, 20 μm or less, or 10 μm or less.
The volume frequency of the first peak is preferably higher than the volume frequency of the second peak.

When the carbonaceous particles have only two peaks, one of the peaks has a maximum in the range of the maximum of the first peak described above, and the other peak has a maximum of the above-mentioned second peak. It is preferable to have a maximum in the range.
When the carbonaceous particles have three or more peaks, at least one peak has a maximum in the range of the maximum of the first peak described above, and another at least one peak has the second peak described above. It is preferable to have a maximum in the range of the maximum of the peak. It may have a peak (hereinafter, also referred to as "third or higher peak") other than the above-mentioned maximum range of the first peak and the above-mentioned maximum range of the second peak, but it does not have it. You may. When the carbonaceous particles have a third or higher peak, the volume frequency thereof is preferably smaller than that of the first peak and the second peak.

The content of carbonaceous particles in the friction material composition for underlaying material of the second embodiment is preferably 3 to 11.5 parts by mass with respect to 100 parts by mass of the friction material composition for underlaying material of the second embodiment. , 5 to 11 parts by mass is more preferable, 7 to 10.5 parts by mass is further preferable, and 7.5 to 10 parts by mass is particularly preferable.

Graphite is preferable as the carbonaceous particles in the friction material composition for the underlaying material of the second embodiment, but those mentioned in the carbonaceous particles contained in the underlaying material of the friction member of the present embodiment described above. May be good.
The shape of the carbonaceous particles in the friction material composition for the underlaying material of the second embodiment, other aspects, and the like will be described in the same manner as the description of the carbonic particles contained in the underlaying material of the friction member of the present embodiment described above. Will be done.

The friction material composition for the underlaying material of the second embodiment may further contain one or more selected from the group consisting of a binder, an organic filler, an inorganic filler other than carbonaceous particles, and a fiber base material. good. The description of the binder, the organic filler, the inorganic filler, and the fiber base material will be described in the same manner as the description of the friction member of the present embodiment described above.

[Underlay material and friction member]
The present invention also provides an underlaying material obtained by molding the friction material composition for an underlaying material according to the second embodiment described above. Furthermore, the present invention also provides a friction member having an upholstery material, the underlaying material and a back plate in this order.
The molding conditions of the friction material composition for the underlaying material, each member constituting the friction member, and the manufacturing method will be described in the same manner as in the above description of the friction member of the present embodiment.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these examples.
The disc brake pads obtained in each example were evaluated according to the following evaluation methods.

[Evaluation method]
(1) Evaluation of powder coating property The disc brake pads produced in each example were powder coated using an electrostatic powder coating device "SFC-QTR100" manufactured by Asahi Sanac Co., Ltd. The film-forming amount (coating film thickness) of the back plate and the underlaying material of the disc brake pad after coating was measured by the following method.
(1-1) Amount of film formation on the back plate The amount of film formation on the back plate is determined by measuring the coating film thickness using a dual type film thickness meter "LZ-200J" manufactured by Ketsuto Kagaku Kenkyusho Co., Ltd., and using the following criteria. Evaluated based on.
A: The coating film thickness exceeds 20 μm B: The coating film thickness is 10 μm or more and 20 μm or less C: The coating film thickness is less than 10 μm (1-2) The film forming amount of the underlaying material is the disc brake after coating. The pad was cut at the position AA in FIG. 1, and the coating film thickness on the cut surface was measured using a microscope (manufactured by Keyence Co., Ltd.) and evaluated based on the following criteria.
A: Coating film thickness exceeds 15 μm B: Coating film thickness is 5 μm or more and 15 μm or less C: Coating film thickness is less than 5 μm

(2) Measurement of shear strength and rust area (evaluation of weather resistance)
The step of immersing the painted disc brake pad in 5% by mass salt water for 10 minutes, leaving it in the air at 23 ° C. for 120 minutes, and drying it at 70 ° C. for 30 minutes is defined as one cycle, which is 500 cycles and 750 cycles. After that, the shear strength was measured and the rusted area on the sheared surface was measured according to JISD 4415 (2007), and the ratio of the rusted area to the entire cross-sectional area was determined.

(3) Measurement of friction coefficient (evaluation of friction characteristics)
The frictional performance of the underlaying material was evaluated in a state where the disc brake pads produced in each example were polished by 50% and the underlaying material was exposed on the sliding surface.
The coefficient of friction was measured based on the Japanese Automotive Standards Organization "JASO C406", and the average value of the coefficient of friction in the second efficacy test was calculated. The larger the coefficient of friction, the better the friction performance.

[Making disc brake pads]
Examples 1-9 and Comparative Examples 1-6
According to the blending amounts shown in Tables 1 and 2, each component is blended for each of the friction material composition for the upholstery material and the friction material composition for the underlaying material, and separately made by Lady Gemixer (manufactured by Matsubo Co., Ltd., trade name: Ray). By mixing with a Digemixer M20), a friction material composition for an upholstery material and a friction material composition for an underlaying material were obtained. The friction material composition for the upholstery material and the friction material composition for the underlaying material were integrally preformed by a molding press (manufactured by Oji Machinery Co., Ltd.). The obtained preformed product was subjected to a steel plate back plate (Hitachi Automotive Systems Co., Ltd.) using a molding press (manufactured by Sanki Seiko Co., Ltd.) under the conditions of a molding temperature of 140 to 160 ° C., a molding pressure of 30 MPa, and a molding time of 5 minutes. Manufactured by heating and pressure molding. The obtained molded product was heat-treated at 200 ° C. for 4.5 hours, polished using a rotary polishing machine, and scorch-treated at 500 ° C. to obtain a disc brake pad. The disc brake pads obtained in Examples and Comparative Examples have a back plate thickness of 6 mm, an upholstery material thickness of 7 mm, an underlaying material thickness of 2 mm, and a friction material projection area of 52 cm ² . The disc brake pad used for measuring the friction coefficient was manufactured with a thickness of the upholstery material of 4 mm and a thickness of the underlaying material of 4 mm, and was obtained by polishing and removing all the upholstery material.
Using the obtained disc brake pads, each measurement and evaluation was performed according to the above method. The results are shown in Table 2.

The details of the carbonaceous particles shown in Table 2 are as follows.
-Graphite 1; average particle size (D ₅₀ ) 40 μm, artificial graphite, shape: spherical-Graphite 2; average particle size (D ₅₀ ) 10 μm, artificial graphite, shape: indefinite shape-Graphite 3; average particle size (D ₅₀ ) 4 μm, natural graphite, shape: indefinite shape ・ Graphite 4; average particle size (D ₅₀ ) 2 μm, artificial graphite, shape: indefinite shape

From Table 2, Examples 1 to 9, which are the friction members of the present embodiment, have a good friction coefficient, a large amount of film formation on the back plate and the underlaying material, and are excellent in powder coatability. Further, the disc brake pad obtained thereby had high shear strength, a small rust area, and excellent weather resistance.
On the other hand, among Comparative Examples 1 to 6 using only one kind of carbonaceous particles, Comparative Examples 1, 2 and 4 to 6 in which the blending amount of the carbonic particles was 4 to 8 parts by mass are powder coatable and It was inferior in weather resistance. Further, in Comparative Example 3 in which the blending amount of the carbonaceous particles was increased to 12 parts by mass, the powder coating property and the weather resistance were good, but the friction coefficient was significantly reduced.

1 Upholstery 2 Underlayment 3 Back plate 4 Disc brake pads

Claims (15)

A friction member having an upholstery material, an underlaying material, and a back plate in this order.
The underlaying material does not contain copper, or even if it contains copper, the copper content is less than 0.5% by mass as a copper element.
Moreover, the friction member is formed by blending two or more kinds of carbonaceous particles having different average particle diameters (D _{50) in the underlaying material.} Of the two or more types of carbonaceous particles, at least one type of carbonic particles is _{carbonaceous particles (A) having an average particle diameter (D 50} ) of 8 to 60 μm, and at least one other type of carbon. The friction member according to claim 1, wherein the quality particles are carbonaceous particles (B) having an average particle diameter (D _{50) of 7 μm or less.} The blending amount of the carbonic particles (A) is 1 to 11 parts by mass with respect to 100 parts by mass of the underlaying material, and the blending amount of the carbonic particles (B) is with respect to 100 parts by mass of the underlaying material. The friction member according to claim 1 or 2, which is 0.1 to 10 parts by mass. The friction member according to any one of claims 1 to 3, wherein the two or more kinds of carbonaceous particles are graphite. Contains two or more types of carbonaceous particles that do not contain copper, or even if they do, the copper content is less than 0.5% by mass as a copper element and the average particle size (D _{50) is different.} Friction material composition for underlaying material. Of the two or more types of carbonaceous particles, at least one type of carbonic particles is _{carbonaceous particles (A) having an average particle diameter (D 50} ) of 8 to 60 μm, and at least one other type of carbon. The friction material composition for an underlaying material according to claim 5, wherein the quality particles are carbonaceous particles (B) having an average particle diameter (D _{50) of 7 μm or less.} The blending amount of the carbonic particles (A) is 1 to 11 parts by mass with respect to 100 parts by mass of the friction material composition for the underlaying material, and the blending amount of the carbonic particles (B) is the underlaying material. The friction material composition for an underlaying material according to claim 6, which is 0.1 to 10 parts by mass with respect to 100 parts by mass of the friction material composition for use. The friction material composition for an underlaying material according to any one of claims 5 to 7, wherein the two or more kinds of carbonaceous particles are graphite. An underlaying material obtained by molding the friction material composition for an underlaying material according to any one of claims 5 to 8. A method for producing a friction material composition for an underlaying material according to any one of claims 5 to 8.
A method for producing a friction material composition for an underlaying material, which comprises two or more kinds of carbonaceous particles having different average particle diameters (D _50). It does not contain copper, or even if it contains copper, the content of copper is less than 0.5% by mass as a copper element, and it contains carbonaceous particles, and the carbonaceous particles have a volume-based frequency distribution. A friction material composition for an underlaying material, which has two or more peaks in the particle size distribution curve shown. The underlaying material according to claim 11, wherein the two or more peaks include a first peak having a maximum in the range of 8 to 60 μm and a second peak having a maximum in the range of 7 μm or less. Friction material composition. The friction material composition for an underlaying material according to claim 11 or 12, wherein the carbonaceous particles are graphite. An underlaying material obtained by molding the friction material composition for an underlaying material according to any one of claims 11 to 13. A friction member having an upholstery material, an underlaying material according to claim 14, and a back plate in this order.

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