Brake pad, metal-containing composition, brake, and method for manufacturing brake pad

Abstract

A brake pad having a metal-containing layer on a sliding surface, the metal-containing layer comprising 70 mass % or more of at least one compound selected from titanium compounds, magnesium compounds, and lithium compounds, and a resin.

Description

Technical Field

[0001] This disclosure relates to brake pads, metal-containing compositions, brakes, and methods for manufacturing brake pads. Background Technology

[0002] Disc brakes used in automobiles, two-wheeled vehicles, etc., are components that use two disc brake pads to clamp a disc rotor and apply braking force through their friction.

[0003] Disc brake pads commonly used in automobiles, two-wheeled vehicles, etc., are manufactured as follows: organic fibers, inorganic fibers, metal fibers, etc., are mixed with friction modifiers and phenolic resin, and then integrally cured into a predetermined shape with a metal plate called a backing plate in a pressing machine. After heat treatment, they are processed into a predetermined shape (see, for example, Patent Document 1). Alternatively, sometimes a surface treatment of high temperature baking, i.e., scorching, is performed after heat treatment to stabilize the coefficient of friction. In addition, after these processes, a mixture of resin, abrasive materials, etc., is sometimes applied to the friction surface. This is done in response to situations where the friction coefficient becomes lower than usual due to insufficient contact between the disc brake pads and the disc rotor when the brake is first used. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent No. 5797073 Summary of the Invention The problem that the invention aims to solve

[0005] The braking force of a disc brake is obtained through the friction between the disc rotor and the brake pads. However, initially (e.g., when it's new), these two components have poor break-in. Typically, the initial surface of the disc rotor is pure iron, but through the formation of a transfer film from the friction material on the surface layer during use, the coefficient of friction, wear, etc., become stable. Therefore, to achieve the designed braking friction force, hundreds of braking cycles are required.

[0006] In recent years, the widespread adoption of electric vehicles has led to increased battery weight, necessitating larger brakes to ensure braking force in emergencies. However, regenerative braking reduces the normal braking load. Consequently, the time required for the designed braking force to be achieved becomes a problem. Furthermore, the advancement of autonomous driving further complicates matters; without consistently maintained braking force, the vehicle may not decelerate as designed, creating another significant issue.

[0007] This disclosure was made in view of the above-mentioned prior circumstances, and its object is to provide a brake pad with excellent stability of initial friction coefficient, a method for manufacturing the brake pad capable of producing the brake pad, a metal-containing composition, and a brake having the brake pad. Methods for solving problems

[0008] The specific means to achieve the above-mentioned goals are as follows. <1> A braking pad has a metal-containing layer on its sliding surface, the metal-containing layer comprising more than 70% by mass of at least one compound selected from titanium compounds, magnesium compounds and lithium compounds, and a resin. <2> according to <1> The braking pad, wherein the metal layer comprises a resin for loading the at least one compound onto the sliding surface, and does not contain particles with an average particle size greater than 50 μm or a fiber substrate. <3> according to <1> or <2> The braking pad, wherein the thickness of the metal layer is 1μm to 1000μm. <4> A metal-containing composition comprising: At least one compound selected from titanium compounds, magnesium compounds, and lithium compounds; and At least one of the resin and resin precursor. The metal-containing composition is used to form a metal-containing layer comprising at least one compound and a resin on a substrate for brake pads. <5> according to <4> The metal-containing composition wherein the at least one material is thermosetting or photocurable. <6> according to <4> or <5> The metal-containing composition wherein the at least one compound comprises the titanium compound, the titanium compound being at least one selected from titanium oxide, lithium titanate, potassium titanate, magnesium titanate, potassium lithium titanate, and titanium dicene. <7> according to <4> ~ <6> The metal-containing composition according to any one of the following methods, wherein the total content of the at least one compound is 1% to 80% by mass. <8> A brake comprising a brake disc (brake rotor) and <1> ~ <3> Braking pad as described in any one of the following statements. <9> A method for manufacturing a brake pad includes the steps of: attaching a powder containing at least one compound selected from titanium compounds, magnesium compounds, and lithium compounds to a substrate of the brake pad, or applying a liquid composition obtained by dissolving or dispersing the powder in a liquid to the substrate of the brake pad. Invention Effects

[0009] According to one aspect of this disclosure, a brake pad with excellent stability of initial coefficient of friction, a method for manufacturing the brake pad, a metal-containing composition, and a brake having the brake pad are provided. Detailed Implementation

[0010] The following describes in detail the methods for implementing this disclosure. However, this disclosure is not limited to the following embodiments. In the following embodiments, unless specifically stated otherwise, the constituent elements (including element steps, etc.) are not essential. The same applies to numerical values ​​and their ranges; they do not limit this disclosure.

[0011] In this disclosure, within the numerical range represented by "~", the values ​​recorded before and after "~" are included as the minimum and maximum values, respectively. In the numerical ranges described in this disclosure in stages, the upper or lower limit value described in one numerical range can be replaced with the upper or lower limit value of other numerical ranges described in stages. Furthermore, the upper or lower limit value of the numerical ranges described in this disclosure can be replaced with the values ​​shown in the embodiments. In this disclosure, each component may contain multiple substances belonging to it. When multiple substances belonging to each component are present in the composition, unless otherwise specified, the content or percentage of each component refers to the total content or percentage of the multiple substances present in the composition. In this disclosure, the particles belonging to each component may include multiple particles. In the case where multiple particles belonging to each component are present in the composition, unless otherwise specified, the particle size of each component refers to a value relating to the mixture of the multiple particles present in the composition. In this disclosure, the term "layer" includes not only the case where it is formed in the whole of the region where the layer exists, but also the case where it is formed only in a part of the region. The average particle size refers to the 50% (median) diameter (D50) obtained from the volume distribution of the particle size distribution measured using a laser diffraction / scattering particle size distribution measuring device. The average particle size can be measured, for example, using the LA-920 (manufactured by Horiba Corporation).

[0012] [Brake pads] The brake pad disclosed herein has a metal-containing layer on the sliding surface, the metal-containing layer comprising more than 70% by mass of at least one compound selected from titanium compounds, magnesium compounds and lithium compounds (hereinafter also referred to as "specific metal compounds") and resin.

[0013] The brake pad disclosed herein exhibits excellent stability of the coefficient of friction during the initial break-in process between the brake pad and the brake disc, thereby shortening the break-in period. The reason for this is speculated as follows: A specific metallic compound penetrates the surface of the brake disc, forming a dense metal-containing layer on the sliding surface, thereby shortening the break-in period and demonstrating stability of the coefficient of friction.

[0014] Furthermore, according to the brake pad disclosed herein, the coefficient of friction of the brake pad is stable, for example, from around 100°C to around 300°C at the beginning of use, particularly around 100°C, which improves the wear of the brake pad. As a result, wear dust can be reduced, and the generation of environmentally and human-harmful substances can be reduced. In addition, the use of environmental pollutants can also be reduced.

[0015] According to the brake pad disclosed herein, the number of braking operations required until the specified braking force is achieved can be reduced. Therefore, even in vehicles with typically low braking loads, such as electric vehicles, the time required to obtain stable braking force can be shortened.

[0016] The brake pad disclosed herein may be, for example, a brake pad for automobiles, two-wheeled vehicles, etc. The brake pad may be a pad for a disc brake.

[0017] The brake pad disclosed herein only requires that it has a metal-containing layer on the sliding surface, and that the metal-containing layer is formed on at least a portion of the sliding surface. The metal-containing layer can be formed on a portion of the sliding surface or on the entire sliding surface. The area of ​​the sliding surface in which the metal-containing layer is formed can be 50% to 100% or 70% to 100% of the total area of ​​the sliding surface.

[0018] Examples of specific metal compounds include compounds containing at least one cation selected from titanium cations, magnesium cations, and lithium cations. Examples include hydroxides, carbonates, sulfates, halides, oxides, complex acid salts such as titanium complex salts, and organometallic compounds containing titanium.

[0019] Examples of hydroxides include magnesium hydroxide and lithium hydroxide. Examples of carbonates include magnesium carbonate and lithium carbonate. Examples of sulfates include titanium sulfate and magnesium sulfate. Examples of halides include titanium trichloroethylene, titanium tetrachloroethylene, magnesium chloride, magnesium bromide, lithium chloride, and lithium bromide. Examples of oxides include titanium oxide and magnesium oxide. Titanium complex acid salts, for example, are composed of M x O (titanium oxide) y Titanium complex salts represented by the general formula. In the general formula, Mx O is an oxide containing the cation represented by M, and x and y are integers. Examples of titanium complex salts include lithium titanate, magnesium titanate, potassium lithium titanate, diocene, potassium titanate, and potassium lithium titanate. Examples of titanium-containing organometallic compounds include titanium dicene and bis(η5-cyclopentadienyl)-bis(2,6-difluoro-3-(1H-pyrrolo-1-yl)-phenyl)titanium.

[0020] The preferred metal compound is a titanium compound. From the viewpoint of shortening the friction stabilization time, the titanium compound is preferably selected from at least one of titanium oxide, lithium titanate, potassium titanate, magnesium titanate, potassium lithium titanate, and titanium dicene.

[0021] The specific metal compound contained in the metal-containing layer may be in particulate form. In this case, from the viewpoint of forming a highly uniform metal-containing layer, the particle size of the specific metal compound is preferably less than 1 / 2 of the film thickness described later. From the viewpoint of safety, the particle size of the specific metal compound is preferably 0.3 μm or more, more preferably 0.3 μm to 50 μm, and even more preferably 0.3 μm to 25 μm.

[0022] The amount of a specific metal compound contained in the metal layer, i.e., the load of a specific metal compound per unit area of ​​the sliding surface of the brake pad, also depends on the density of the specific metal compound. However, from the viewpoint of appropriately demonstrating the effects of the invention and reducing the amount of the specific metal compound used, a density of 0.01 mg / cm³ is preferred. 2 ~25mg / cm 2 More preferably 0.2 mg / cm³ 2 ~12.5mg / cm 2 .

[0023] Methods for forming a metal-containing layer on the sliding surface of a brake pad include attaching a powder of a specific metal compound or a powder containing a specific metal compound to the substrate of the brake pad; applying a liquid composition, formed by dissolving or dispersing the powder in a liquid, to the substrate of the brake pad; and forming the metal-containing layer on the sliding surface concurrently or in stages during the manufacturing process of the brake pad. Methods for applying the metal-containing layer to the substrate of the brake pad include applying the liquid composition using a dispenser, spraying, casting, spin coating, or similar methods.

[0024] From the viewpoint of suppressing powder shedding, the metal-containing layer comprises a resin in which a specific metal compound is supported on the sliding surface. Preferably, the resin in which the specific metal compound is supported on the sliding surface is a resin capable of forming a resin coating on the sliding surface; for example, it may be formed from a resin precursor.

[0025] As a method for forming a metal-containing layer comprising a resin on which a specific metal compound is supported on the sliding surface, an example is a method of dissolving or dispersing a powder of a specific metal compound or a powder containing a specific metal compound in a liquid, and then applying a liquid composition formed by dissolving or dispersing the aforementioned resin or its resin precursor in the liquid to the matrix of a brake pad.

[0026] The aforementioned resin or its resin precursor is preferably dissolved in a liquid that dissolves or disperses the powder. When using a liquid composition, heating is preferably performed after the liquid composition is applied in order to remove the liquid by distillation. The heating temperature depends on the boiling point of the liquid in the liquid composition, and is preferably between -30°C and +130°C.

[0027] When using a liquid composition comprising the above-described resin or its resin precursor, the resin coating formed on the sliding surface can be heated as needed to form a metal-containing layer comprising a resin in which a specific metal compound is supported on the sliding surface. Heating can also be performed at a temperature above the melting point of the resin, as needed.

[0028] The aforementioned resin or its resin precursor may be a thermoplastic material, or a thermosetting or photocurable material. For example, the resin coating formed on the sliding surface may be heated or irradiated with light, thereby curing the resin coating to form a metal-containing layer.

[0029] The aforementioned resin or its resin precursor, which is a thermosetting or photocurable material, can also be dissolved or dispersed in a liquid that dissolves or disperses the powder. From the viewpoint of adjusting the melting point of the material and the viscosity of the liquid composition, the aforementioned resin and its resin precursor can be used together. When the resin precursor is in a liquid state, the resin precursor can be a liquid that dissolves or disperses the powder, or it may not contain any other liquid.

[0030] When using the aforementioned resin or its resin precursor as a thermosetting material, the resin coating needs to be heated to a temperature higher than the curing start temperature. When further using a polymerization initiation catalyst, the resin coating needs to be heated to a temperature above its polymerization initiation temperature. When using the aforementioned resin or its resin precursor as a photocurable material, a photopolymerization initiator is preferred, and the wavelength and exposure amount of the photopolymerization initiator need to be suitable.

[0031] As a method for forming a specific metal-containing layer, another example is a method of pressurizing and heating a powder containing a specific metal compound or a powder containing a specific metal compound mixed with the aforementioned resin or its resin precursor on the sliding surface side of the brake pad substrate. Alternatively, when manufacturing the brake pad substrate, pressurizing and heating can be performed in a mold using a two-layer filling friction material composition and a backing.

[0032] Examples of the aforementioned resins include epoxy resins, phenolic resins, polyurethane resins, fluororesins, polyester resins, amide resins, amide-imide resins, imide resins, melamine resins, polyurethane resins, phenoxy resins, silicone resins, silicate resins, acrylic resins, and olefin resins. Examples of precursors for these resins are also provided. The above-mentioned resins or their resin precursors may be used independently, or two or more may be used in combination. From the viewpoint of coatability and ease of acquisition, the resin and resin precursors described above preferably include at least one selected from epoxy resin, phenolic resin, silicate resin, acrylic resin and precursors thereof, more preferably include at least one selected from phenolic resin and acrylic resin, further preferably include phenolic resin, and particularly preferably include thermosetting phenolic resin.

[0033] The total content of a specific metal compound relative to the total metal layer can be 10% to 80% by mass or 20% to 70% by mass.

[0034] The resin content relative to the total metal layer can be 20% to 90% by mass or 30% to 80% by mass.

[0035] The total content of specific metal compounds and resins is 70% or more by mass relative to the total metal layer content, which can be 70% to 100% by mass or 90% to 100% by mass.

[0036] The metal-containing layer preferably comprises a resin in which at least one compound is supported on the sliding surface, and does not contain particles with an average particle size greater than 50 μm or fiber substrates. When the brake pad has a friction material comprising particles with an average particle size greater than 50 μm and fiber substrates, the metal-containing layer is preferably a layer different from the friction material, and is formed on at least a portion of the friction material.

[0037] The thickness of the metal layer can be 1μm to 1000μm or 10μm to 500μm. By keeping the thickness of the metal layer below 500μm, the friction stabilization time can be shortened, and the tar formation of the resin due to heating, which is the cause of the decrease in the coefficient of friction known as thermal decay, can be suppressed.

[0038] [Metal-containing composition] The metal-containing composition disclosed herein comprises: at least one compound selected from titanium compounds, magnesium compounds, and lithium compounds (a specific metal compound); and at least one material selected from resin and resin precursor, said metal-containing composition being used to form a metal-containing layer comprising said at least one compound and resin on a substrate for a brake pad.

[0039] The metal-containing composition disclosed herein is used, for example, to form a metal-containing layer on the sliding surface of a brake pad substrate formed using a friction material and a backing. The friction material may be, for example, a component molded from a friction material composition comprising inorganic fibers, organic fibers, metal fibers, grinding materials, friction modifiers, and phenolic resin. By forming the metal-containing layer using the metal-containing composition of this disclosure, the aforementioned brake pad of this disclosure can be obtained.

[0040] As a preferred embodiment of the metal-containing composition disclosed herein, the specific metal compound and at least one of the resin and resin precursor are included, as described in the above-described item on brake pads.

[0041] The metal-containing composition disclosed herein can be a liquid material (such as the liquid composition described above) or a powder material. From the viewpoint of being able to form a highly uniform metal-containing layer and to employ various application methods, a liquid material is preferred. As a method for applying powder material to the substrate of the brake pad, examples include powder coating using a friction gun, corona gun, etc. Alternatively, a metal-containing layer can be formed by pressurizing and heating during manufacturing. As a method for applying liquid material to the substrate of the brake pad, examples include spraying, roller coating, etc.

[0042] From the perspective of suppressing powdering and thermal decay, the ratio of the total amount of resin and resin precursor to the total amount of a specific metal compound (resin and resin precursor / specific metal compound) can be 0.2 to 10, 0.5 to 8, or 1 to 5 by mass.

[0043] The metal-containing composition disclosed herein comprises a specific metal compound and at least one material selected from resin and resin precursor as essential components. As needed, it may include a liquid for dissolving or dispersing the specific metal compound (e.g., a specific metal compound in powder form), a polymerization initiator, other additives, etc.

[0044] From the viewpoint of forming a metal-containing layer with excellent uniformity of film thickness, the metal-containing composition of this disclosure preferably contains a liquid that dissolves or disperses a specific metal compound. The total content of the specific metal compound can also be appropriately adjusted depending on whether the specific metal compound is dissolved or dispersed in the liquid.

[0045] In the metal-containing composition disclosed herein, from the viewpoint that it is possible to spray and the film thickness can be easily adjusted, the total content of a particular metal compound relative to the total amount of the metal-containing composition can be 1% to 80% by mass or 5% to 70% by mass.

[0046] In the metal-containing composition disclosed herein, the total content of resin and resin precursor relative to the total amount of the metal-containing composition can be 3% to 99% by mass or 10% to 95% by mass.

[0047] When a liquid that dissolves or disperses a specific metal compound is used in the metal-containing composition disclosed herein, the total content of the specific metal compound, as well as the resin and resin precursor, relative to the total amount of the metal-containing composition may be 5% to 50% by mass or 10% to 30% by mass.

[0048] As a liquid for dissolving or dispersing specific metal compounds, from the viewpoint of evaporation at room temperature or the usable temperature range of a general hot air dryer, a liquid with a boiling point of -30°C to 220°C is preferred; from the viewpoint of drying efficiency, a liquid with a boiling point of -30°C to 130°C is more preferred. By setting the boiling point to -30°C or higher, there is a tendency to easily adjust the film thickness by adjusting the evaporation rate of the liquid; by setting the boiling point to 130°C or lower, there is a tendency to reduce the heat required to remove the liquid by distillation.

[0049] Examples of liquids with boiling points ranging from -30°C to 220°C include water, diethyl ether, acetone, methyl ethyl ketone, ethyl acetate, ethanol, toluene, xylene, N-methylpyrrolidone, dimethylacetamide, and 1-methoxy-2-propanol. Examples of liquids with boiling points ranging from -30°C to 130°C include diethyl ether, acetone, methyl ethyl ketone, ethyl acetate, ethanol, toluene, and 1-methoxy-2-propanol.

[0050] When a liquid that dissolves or disperses a specific metal compound is used in the metal-containing composition disclosed herein, the content of the liquid relative to the total amount of the metal-containing composition may be 30% to 95% by mass or 50% to 90% by mass.

[0051] When at least one of the resin and resin precursor is a thermosetting or photocurable material, the metal-containing composition disclosed herein may contain a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator.

[0052] As polymerization initiators, commercially available free radical and cationic polymerization initiators can be used, as well as free radical polymerization initiators based on organic peracids or azo compounds. As a free radical photopolymerization initiator, bis(η5-cyclopentadienyl)-bis(2,6-difluoro-3-(1H-pyrrolo-1-yl)-phenyl)titanium (e.g., Irgacure 784 from IGM Resins) can be used. This material can function as both a photopolymerization initiator and a titanium compound.

[0053] The metal-containing compositions disclosed herein may include other additives. Examples of such additives include crosslinking agents, sensitizers, friction modifiers, viscosity modifiers, surfactants, leveling agents, metal passivators, colorants, and fragrances.

[0054] Examples of crosslinking agents include cyclohexamethylenetetramine. When using a crosslinking agent, it is preferable to further use a phenolic resin, and the amount of crosslinking agent used is preferably 1% to 12% by mass, more preferably 3% to 8% by mass, relative to the phenolic resin contained in the metal-containing composition.

[0055] [Brake] The brake disclosed herein includes a brake disc and the aforementioned brake pads. The brake may include a disc rotor and disc brake pads, and may be used in automobiles, two-wheeled vehicles, etc.

[0056] Brake discs for braking can be made of iron or iron alloys, preferably cast iron or stainless steel.

[0057] As a brake pad, it can be a component formed by molding a friction material composition and a backing. A primer layer for surface modification aimed at improving the adhesion of the backing to the friction material, and an adhesive layer for bonding the backing to the friction material may also be present between the backing and the friction material. [Example]

[0058] The present disclosure will now be described in more detail by way of examples, but the present disclosure is not limited to these examples.

[0059] (Preparation of anatase titanium dioxide coating solution) 2g of anatase titanium dioxide (manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.) was dispersed in a solution of 4g phenolic resin and 20g methyl ethyl ketone to obtain anatase titanium dioxide coating solution. As the phenolic resin, phenolic resin 1 containing 6% by mass of cyclohexamethylenetetramine was used, which was an unmodified phenolic resin (manufactured by Cashew Corporation, free of cyclohexamethylenetetramine). Since titanium dioxide settles over time, it was thoroughly stirred to disperse the titanium dioxide before use.

[0060] [Example 1] (Fabrication of a liner containing anatase titanium dioxide on the sliding surface) On the surface of the phenolic resin liner 2 described later, the anatase titanium oxide coating liquid prepared above was sprayed in a non-uniform manner to obtain a liner with a coating layer having a calculated thickness of approximately 200 μm. Then, the disc brake liner was heated in stages from 125°C to 200°C in a constant temperature oven to cure the phenolic resin, thereby obtaining a test liner with a titanium oxide layer.

[0061] [Comparative Example 1] (Preparation of phenolic resin liner 1) 20g of phenolic resin 1 was filled into the mold, and the temperature was gradually increased from 125℃ to 200℃ under reduced pressure (3MPa~6MPa) to obtain the test liner.

[0062] [Comparative Example 2] (Preparation of phenolic resin liner 2) 7g of barium sulfate (manufactured by Fujifilm and Koichi Chemical Co., Ltd.), 2.5g of aramid fiber (manufactured by Teijin-DuPont), 0.5g of α-alumina (manufactured by Fujifilm and Koichi Chemical Co., Ltd.), and 9g of phenolic resin 1 were uniformly mixed and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in the range of 3MPa to 6MPa to obtain the test liner.

[0063] (Friction Evaluation) The test blocks for each embodiment or comparative example were cut into test pieces (10mm × 10mm × approximately 15mm, 2 pieces). Using cast iron brake discs, the time and temperature until the coefficient of friction stabilized were evaluated using a friction measuring instrument (FRICTRON EFM-3-F-ADX, A&D Corporation). The test conditions were 3000 rpm and 370 N. Furthermore, the temperature was continuously measured using thermocouples at an internal temperature approximately 5mm from the surface of the test block.

[0064] The coefficient of friction initially increases, then gradually decreases and stabilizes. The coefficient of friction is evaluated by approximating it using a fifth-order equation obtained from the first 30 seconds via numerical processing (Microsoft Excel). The differential of this approximation is calculated, and the time and temperature at which a change exceeds -0.001 are considered frictionally stable. The results are shown in Table 1.

[0065]

[0066] As shown in Example 1 of Table 1, the coefficient of friction was stabilized by coating the surface of the brake pad with an anatase titanium oxide coating liquid. This is presumably because a specific metal compound penetrates the surface of the brake disc, forming a dense surface film on the sliding surface of the brake disc, thereby exhibiting initial stability of the coefficient of friction.

[0067] To identify a specific metal compound that exhibits the same effect as in Example 1, a liner mimicking the surface was fabricated and a friction test was conducted.

[0068] [Example 2] (Fabrication of liner containing anatase titanium dioxide) 2g of anatase titanium dioxide (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) and 18g of phenolic resin 1 were uniformly mixed and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure (3MPa~6MPa) to obtain the test liner.

[0069] [Example 3] (Preparation of the titanium cadmium liner) 2g of titanium dicene (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) and 18g of phenolic resin 1 were uniformly mixed and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in a pressure range of 3MPa to 6MPa to obtain the test liner.

[0070] [Example 4] (Preparation of potassium titanate liner) 2g of potassium titanate (manufactured by Alfa Aesar) and 18g of phenolic resin 1 were uniformly mixed and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in a pressure range of 3MPa to 6MPa to obtain the test liner.

[0071] [Example 5] (Preparation of lithium carbonate-containing liner) 2g of lithium carbonate (manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.) and 18g of phenolic resin 1 were uniformly mixed and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in a pressure range of 3MPa to 6MPa to obtain the test liner.

[0072] [Example 6] (Preparation of magnesium oxide-containing liner) 2g of heavy magnesium oxide (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) and 18g of phenolic resin 1 were mixed evenly and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in the range of 3MPa to 6MPa to obtain the test liner.

[0073] [Example 7] (Preparation of magnesium sulfate-containing liner blocks) 2g of magnesium sulfate (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) and 18g of phenolic resin 1 were mixed evenly and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in the range of 3MPa to 6MPa to obtain the test liner.

[0074] [Example 8] (Preparation of magnesium hydroxide-containing liner) 2g of magnesium hydroxide (manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.) and 18g of phenolic resin 1 were mixed evenly and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in the range of 3MPa to 6MPa to obtain the test liner.

[0075] [Example 9] (Preparation of lithium sulfate-containing liner) 2g of lithium sulfate (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) and 18g of phenolic resin 1 were uniformly mixed and filled into a mold. The temperature was gradually increased from 125°C to 200°C under reduced pressure in a pressure range of 3MPa to 6MPa to obtain the test liner.

[0076] Friction evaluation was performed using the test blocks from Examples 2-9. The friction evaluation was conducted using the same method as described above, and the results are shown in Table 2 together with those from Comparative Examples 1 and 2.

[0077]

[0078] As shown in Examples 2-9 of Table 2, by including a specific metal compound, the time until friction stabilizes is shortened, and the coefficient of friction stabilizes at a lower temperature. It is speculated that, similar to Example 1, the specific metal compound penetrates the surface of the brake disc, forming a dense surface film on the sliding surface of the brake disc, thereby exhibiting initial stability of the coefficient of friction.

[0079] The entire disclosure of Japanese Patent Application 2024-057351, filed on March 29, 2024, is incorporated herein by reference. All documents, patent applications and technical standards described in this specification are incorporated herein by reference to the extent that each document, patent application and technical standard is specifically described and incorporated herein by reference.

Claims

1. A braking pad having a metal-containing layer on its sliding surface, said metal-containing layer comprising 70% by mass or more of at least one compound selected from titanium compounds, magnesium compounds and lithium compounds, and a resin.

2. The brake pad according to claim 1, wherein, The metal-containing layer comprises a resin for loading the at least one compound onto the sliding surface, and does not contain particles with an average particle size greater than 50 μm or a fiber substrate.

3. The brake pad according to claim 1, wherein, The thickness of the metal-containing layer is 1 μm to 1000 μm.

4. A metal-containing composition comprising: At least one compound selected from titanium compounds, magnesium compounds, and lithium compounds; and At least one of the resin and resin precursor. The metal-containing composition is used to form a metal-containing layer comprising at least one compound and a resin on a substrate for brake pads.

5. The metal-containing composition according to claim 4, wherein, The at least one material is thermosetting or photosetting.

6. The metal-containing composition according to claim 4, wherein, The at least one compound includes the titanium compound. The titanium compound is selected from at least one of titanium oxide, lithium titanate, potassium titanate, magnesium titanate, potassium lithium titanate, and titanium dicene.

7. The metal-containing composition according to any one of claims 4 to 6, wherein, The total content of the at least one compound is 1% to 80% by mass.

8. A brake comprising a brake disc for braking and a brake pad according to any one of claims 1 to 3.

9. A method for manufacturing a brake pad, comprising the steps of: attaching a powder comprising at least one compound selected from titanium compounds, magnesium compounds and lithium compounds to a substrate of the brake pad, or imparting a liquid composition obtained by dissolving or dispersing the powder in a liquid to the substrate of the brake pad.

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