Friction member and method for manufacturing a friction member

Abstract

The present invention relates to a friction material having a thermoplastic resin composition, and a friction member having a high friction coefficient and a manufacturing method of the friction member. More specifically, a manufacturing method of a friction member and a friction member, the manufacturing method characterized in that it is a manufacturing method of a friction member at least including a friction material and a back plate supporting the friction material, the manufacturing method having the following step: melt molding a resin composition at or above the softening flow temperature of a thermoplastic resin (A), forming the friction material and the back plate within the same molding cycle, the resin composition containing the thermoplastic resin (A) and an inorganic filler (B) as essential components, the thermoplastic resin (A) having a melt viscosity (V6) of 30 Pa·s or less and a flow softening temperature of 130°C or more, and the compounding amount of the thermoplastic resin (A) being 50 parts by mass or less with respect to 100 parts by mass of the resin composition.

Description

Technical Field

[0001] This invention relates to a friction component and a method for manufacturing the friction component. Background Technology

[0002] Friction components (or friction materials) used in braking materials (e.g., brake pads, brake discs) for vehicles, industrial machinery, robots, etc., need to possess various properties, such as high coefficient of friction, wear resistance, heat resistance, and mechanical strength. Furthermore, in recent years, to achieve a sustainable society, the reuse of materials used has been actively researched; therefore, using materials with excellent recyclability has become a design consideration. Traditionally, friction materials, as components of brakes, can be mainly divided into organic and inorganic systems. Organic systems primarily use thermosetting resin compositions mixed with filler materials. For example, Patent Document 1 discloses a thermosetting resin composition for friction materials in which lignocellulose nanofibers are dispersed in the thermosetting resin. Furthermore, Patent Document 2 discloses a thermosetting resin composition for friction materials comprising phenolic resin, hexamethylenetetramine, and a triazine compound.

[0003] However, compared to thermoplastic resins, thermosetting resins suffer from problems such as longer processing times and poor recyclability. On the other hand, with the development of engineering plastics and super engineering plastics with melting points higher than traditional general-purpose thermoplastic resins, it is now possible to manufacture thermoplastic resin compositions with superior heat resistance, potentially achieving the heat resistance required for the aforementioned friction components. Furthermore, by compounding materials, it is also expected that the tribological properties of this resin composition can be improved, thus increasing the demand for material development.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-131477

[0007] Patent Document 2: Japanese Patent Application Publication No. 2020-169245 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] Therefore, the problem to be solved by the present invention is to provide a friction component and a method for manufacturing the friction component, the friction component having a friction material composed of a thermoplastic resin composition and having a high coefficient of friction.

[0010] Solution for solving the problem

[0011] In other words, the present invention relates to a method for manufacturing a friction component, characterized in that,

[0012] It is a method for manufacturing a friction component that includes at least a friction material and a back plate supporting the friction material.

[0013] The manufacturing method comprises the following steps: melting and molding a resin composition above the softening flow temperature of the thermoplastic resin (A) to form the friction material and the backing plate within the same molding cycle.

[0014] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0015] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

[0016] In addition, the present invention relates to a method for manufacturing a friction component, characterized in that,

[0017] It is a method for manufacturing a friction component that includes at least a friction material and a back plate supporting the friction material.

[0018] The manufacturing method includes the following steps: in a mold in which the back plate is inserted, a resin composition is melted and molded at a temperature above the softening flow temperature of the thermoplastic resin (A) to form a friction material.

[0019] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0020] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

[0021] In addition, the present invention relates to a friction component, characterized in that,

[0022] It is a friction component that includes at least a friction material and a back plate supporting the friction material.

[0023] The friction material and the backing plate are formed by melting and molding a resin composition above the softening flow temperature of the thermoplastic resin (A).

[0024] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0025] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

[0026] In addition, the present invention relates to a friction component, characterized in that,

[0027] It is a friction component that includes at least a friction material and a back plate supporting the friction material.

[0028] The friction material is formed by melting and molding a resin composition above the softening flow temperature of thermoplastic resin (A).

[0029] The back plate is selected from at least one of the following: metal components and ceramic components.

[0030] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0031] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

[0032] The effects of the invention

[0033] According to the present invention, a friction component having a high coefficient of friction and a method for manufacturing the friction component are provided, the friction component comprising a friction material composed of a thermoplastic resin composition. Detailed Implementation

[0034] The embodiments of the present invention will be described in detail below, but the scope of the present invention is not limited to the one embodiment described herein, and various modifications can be made without departing from the spirit of the present invention. Furthermore, for a specific parameter, when multiple upper and lower limits are recorded, any combination of the upper and lower limits can be used as an appropriate numerical range.

[0035] Manufacturing method of friction components

[0036] The method for manufacturing the friction component according to this embodiment is characterized in that,

[0037] It is a method for manufacturing a friction component that includes at least a friction material and a back plate supporting the friction material.

[0038] The manufacturing method comprises the following steps: melting and molding a resin composition to form the friction material and the backing plate within the same molding cycle.

[0039] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0040] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition. This will be explained below.

[0041] In this invention, the friction component refers to the brake pads in a disc brake, the brake shoes in a drum brake, and the rotor in an electromagnetic brake, and is composed of friction material (brake lining) and a backing plate. The backing plate is a component that supports the friction material and is installed on the side of the friction component that does not contact the braked component. Furthermore, the braked component refers, for example, to the brake drum in a drum brake, the brake disc in a disc brake, and the armature in an electromagnetic brake.

[0042] In this embodiment, the method for forming the friction material and the backing plate by melt molding the resin composition is not particularly limited, as long as it does not impair the effect of the present invention, and known methods and apparatus can be used. For example, it can be applied to various melt molding processes such as injection molding, compression molding, extrusion molding of composite materials, sheets, pipes, pultrusion molding, blow molding, and transfer molding, but it is particularly suitable for injection molding because of its excellent demolding properties. When using injection molding, various molding conditions are not particularly limited, and conventional methods can be used for molding. For example, in the injection molding machine, after the resin composition is melted in a temperature range above the softening flow temperature of the thermoplastic resin (A), preferably above +10°C, more preferably from +10°C to +100°C, and even more preferably from +20°C to +50°C, it can be injected into the mold from the resin outlet for molding. At this time, the mold temperature can also be set within a known temperature range, for example, room temperature (23°C) to 300°C, preferably 130 to 190°C.

[0043] In this embodiment, the friction material and backing plate are formed within the same molding cycle. The same molding cycle means that molding is completed within a single melt-curing cycle. Specifically, the friction material and backing plate are formed by performing two processes in sequence: a plasticizing process that heats the resin to above its melting point to melt it, and a cooling process that cools / cures the molten resin in the plasticizing process in a mold below its crystallization temperature. This does not include cases where the friction material and backing plate, formed in their respective independent molding cycles, are integrated in subsequent processes.

[0044] Furthermore, the manufacturing method of the friction component in this embodiment also includes a method in which the friction material also functions as a backing plate.

[0045] Resin Composition

[0046] The method for manufacturing the friction component of the present invention involves melt molding a resin composition to form the friction material and the backing plate within the same molding cycle. Furthermore, the resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of 30 Pa·s or less and a flow softening temperature of 130°C or more, and an inorganic filler (B) as essential components, and the amount of the thermoplastic resin (A) is 50 parts by mass or less relative to 100 parts by mass of the resin composition. The following description will illustrate this method.

[0047] Thermoplastic resin (A)

[0048] In this embodiment, the thermoplastic resin (A) is not particularly limited as long as its melt viscosity (V6) is 30 Pa·s or less and its flow softening temperature is 130°C or more, and known materials can be used. For example, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; and polyamide resins such as polyamide-6 (nylon-6), polyamide-11 (nylon-11), polyamide-12 (nylon-12), polyamide-46 (nylon-46), polyamide-66 (nylon-66), polyamide-610 (nylon-610), polyamide-6T (nylon-6T), polyamide-6I (nylon-6I), polyamide-9T (nylon-9T), polyamide-M5T (nylon-M5T), and poly(m-phenylene adipamide) (nylon-MXD6) are also used. Ethylene-vinyl ester copolymers, ethylene-unsaturated carboxylic acid ester copolymers, and other ethylene-unsaturated ester copolymers; ethylene-unsaturated carboxylic acid copolymers or their ionomers; chlorine-based resins such as polyvinyl chloride and polyvinylidene chloride; fluorine-based resins such as polytetrafluoroethylene, ethylene tetrafluoroethylene copolymers, polyvinylidene fluoride, and polyvinyl fluoride; polystyrene resins such as syndiotactic polystyrene; polyether ether ketone resins, polyether ketone resins, polyether ketone ketone resins, and other polyether resins; polycarbonate resins; polyarylene sulfide resins, represented by polyphenylene sulfide resins, polyarylene ether resins, and other polyphenylene resins; polyvinyl acetate resins; polyacrylonitrile resins; liquid crystal polymers (LCPs), etc. Furthermore, one of these thermoplastic resins can be used alone, or two or more can be used in combination. From the perspective of heat resistance and low water absorption, engineering plastics or super engineering plastics are preferred, and polybutylene terephthalate, polyamide-6T (nylon-6T), polyamide-9T (nylon-9T), polyamide-10T (nylon-10T), poly(m-phenylene adipamide) (nylon-MXD6), and polyaryl sulfide resin (hereinafter referred to as PAS) are even more preferred, with PAS resin being particularly preferred.

[0049] When PAS resin is used as the thermoplastic resin (A), its non-Newtonian index is not particularly limited, but is preferably in the range of 0.90 to 2.00. In this invention, the non-Newtonian index (N value) is calculated using a capillary rheometer at a melting point of +20°C and with an orifice length (L) to orifice diameter (D) ratio of L / D = 40, by measuring the shear rate (SR) and shear stress (SS), and using the following formula. A non-Newtonian index (N value) closer to 1 indicates a more linear structure; a higher non-Newtonian index (N value) indicates a more developed branched structure.

[0050] [Mathematical Expression 1]

[0051]

[0052] Where SR is the shear rate (seconds) -1 ), SS is the shear stress (dynes / cm²), and K is a constant.

[0053] Regarding the melt viscosity (V6) of the thermoplastic resin (A) used in this embodiment, from the perspective of balancing processability and mechanical strength, the melt viscosity (V6) measured at 300°C is preferably 30 Pa·s or less, more preferably 20 Pa·s or less, and more preferably 10 Pa·s or less. There is no particular limitation on the lower limit of the melt viscosity (V6), but from the perspective of mechanical strength, 2 Pa·s or more is preferred. The melt viscosity (V6) is measured using a Shimadzu CFT-500D rheometer. The melt viscosity is measured after applying a load of 1.96 MPa at a temperature of 20°C above the softening flow temperature of the thermoplastic resin (A), using an orifice with a length-to-diameter ratio of 10 / 1, and holding for 6 minutes. Furthermore, in this invention, the temperature at which the thermoplastic resin (A) reaches a softened flow state due to heating (which may be the melting point for crystalline resins and the glass transition temperature for amorphous resins) is simply referred to as the "softening flow temperature".

[0054] Regarding the amount of thermoplastic resin (A), from the perspective of excellent tribological properties and dimensional stability, it is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, and even more preferably 35 parts by weight or less, relative to 100 parts by weight of the resin composition. Furthermore, from the perspective of processability, it is more preferably 10 parts by weight or more, even more preferably 15 parts by weight or more, and particularly preferably 20 parts by weight or more, relative to 100 parts by weight of the resin composition.

[0055] Furthermore, the thermoplastic resin (A) used in this embodiment can also be a recycled thermoplastic resin. When the thermoplastic resin (A) used in this embodiment contains the recycled material, there is no particular limitation on the proportion of the recycled material in the resin. For example, it is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, and even more preferably 30 parts by weight or less. The processing (recycling treatment) of recycled materials from thermoplastic resin molded articles can be carried out by known methods. For example, methods such as cutting or crushing the molded articles into chip or granule form, dissolving the subdivided molded articles in a solvent and then performing solid-liquid separation to remove filler materials, or contacting the subdivided molded articles with a solvent to extract and remove components other than thermoplastic resin, etc. Recycling treatment is usually based on recycled thermoplastic resin molded articles provided by consumers, non-standard thermoplastic resin molded articles provided by molded article manufacturers, or losses generated during molding (such as runners in injection molding). By using recycled thermoplastic resin, the amount of resin and molded articles requiring waste disposal can be reduced, thereby reducing the environmental burden.

[0056] Inorganic filler materials (B)

[0057] For the inorganic filler material (B) used in this embodiment, any commonly known material can be used as long as it does not impair the effect of the present invention. Various shapes of filler materials can be listed, such as granular, plate-like, and fibrous materials. For example, glass fiber, carbon fiber, glass beads, glass sheets, barium sulfate, clay, pyrophyllite, bentonite, sericite, mica, talc, attapulgite, ferrite, calcium silicate, calcium carbonate, magnesium carbonate, zeolite, abrasive fibers, calcium sulfate, potassium titanate, lithium titanate, potassium magnesium titanate, sodium titanate, alumina, wollastonite, magnesium oxide, chromite, chromium oxide, copper, iron oxide, zirconium oxide, zirconium silicate, rock wool, and other filler materials can be used.

[0058] There is no particular limitation on the amount of inorganic filler (B), but from the viewpoint of excellent mechanical properties and dimensional stability, the amount of inorganic filler (B) is preferably 40 to 350 parts by weight relative to 100 parts by weight of the resin composition, more preferably 50 to 320 parts by weight, and even more preferably 60 to 300 parts by weight.

[0059] Solid lubricating materials (C)

[0060] From the viewpoint of further improving the sliding properties, a solid lubricant (C) can be optionally incorporated into the resin composition of this embodiment. In this invention, a solid lubricant refers to a substance that is solid at room temperature (23°C) and has a coefficient of kinetic friction of 0.2 or less.

[0061] There are no particular limitations on the solid lubricant material (C) that can be used in this embodiment, and known materials can be used. Examples include polytetrafluoroethylene (PTFE), polyethylene, graphite, boron nitride, molybdenum disulfide, carbon fiber, melamine cyanurate, etc. In particular, from the viewpoint of sliding and processability, PTFE, polyethylene, and graphite are preferred.

[0062] When the solid lubricant (C) is incorporated into the resin composition of this embodiment, the amount incorporated is preferably 2 to 50 parts by weight relative to 100 parts by weight of the thermoplastic resin (A), more preferably 4 to 40 parts by weight. Within this range, the resin composition exhibits good processability, while the molded article exhibits excellent wear resistance and mechanical strength, and is therefore preferred.

[0063] Organic filler material (D)

[0064] From the viewpoint of further improving abrasion resistance and vibration damping properties, the organic filler material (D) can be optionally mixed into the resin composition of this embodiment.

[0065] There are no particular limitations on the organic filler material (D) that can be used in this embodiment, and known materials can be used. Examples include aramid fibers, thermoplastic elastomers, thermosetting elastomers, ionomers, cashew nut shell particles, rosin, etc. In particular, from the viewpoint of processability, thermoplastic elastomers, thermosetting elastomers, and ionomers are preferred.

[0066] When the organic filler material (D) is incorporated into the resin composition of this embodiment, the amount incorporated is preferably 1 to 20 parts by weight relative to 100 parts by weight of the thermoplastic resin (A), and more preferably 2 to 15 parts by weight. Within this range, the resin composition exhibits good abrasion resistance and excellent vibration damping properties, and is therefore preferred.

[0067] Examples of thermoplastic elastomers include polyolefin-based elastomers, fluorinated elastomers, and silicone elastomers, with polyolefin-based elastomers being a preferred example. Examples of polyolefin-based elastomers include homopolymers of α-olefins, copolymers of two or more α-olefins, and copolymers of one or more α-olefins with a vinyl polymerizable compound having a functional group. In this case, examples of α-olefins include α-olefins with 2 to 8 carbon atoms, such as ethylene, propylene, and 1-butene. Furthermore, examples of functional groups include carboxyl groups, anhydride groups (-C(=O)OC(=O)-), epoxy groups, amino groups, hydroxyl groups, mercapto groups, isocyanate groups, and oxazoline groups. Furthermore, examples of the vinyl polymerizable compounds with functional groups include vinyl acetate; α,β-unsaturated carboxylic acids such as (meth)acrylic acid; alkyl esters of α,β-unsaturated carboxylic acids such as methyl acrylate, ethyl acrylate, and butyl acrylate; metal salts of α,β-unsaturated carboxylic acids such as ionomers (the metal can be an alkali metal such as sodium, an alkaline earth metal such as calcium, or zinc); glycidyl esters of α,β-unsaturated carboxylic acids such as glycidyl methacrylate; α,β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; and one or more derivatives of the aforementioned α,β-unsaturated dicarboxylic acids (monoesters, diesters, anhydrides). The thermoplastic elastomer can be used alone or in combination of two or more.

[0068] To further improve the bonding strength, the resin composition of this embodiment may optionally include a silane coupling agent as a component. There are no particular limitations on the silane coupling agent, as long as it does not impair the effects of the invention; however, silane coupling agents having functional groups capable of reacting with carboxyl groups, such as epoxy, isocyanate, amino, or hydroxyl groups, are preferred. Examples of such silane coupling agents include: alkoxysilane compounds containing epoxy groups, such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc.; and alkoxysilane compounds containing isocyanate groups, such as γ-isocyanatepropyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-isocyanatepropylmethyldimethoxysilane, γ-isocyanatepropylmethyldiethoxysilane. Alkane, γ-isocyanate propyl ethyl dimethoxysilane, γ-isocyanate propyl ethyl diethoxysilane, γ-isocyanate propyl trichlorosilane, etc.; amino-containing alkoxysilane compounds, such as γ-(2-aminoethyl)aminopropyl methyl dimethoxysilane, γ-(2-aminoethyl)aminopropyl trimethoxysilane, γ-aminopropyl trimethoxysilane, etc.; hydroxyl-containing alkoxysilane compounds, such as γ-hydroxypropyl trimethoxysilane, γ-hydroxypropyl triethoxysilane, etc.

[0069] The resin composition of this embodiment may also be mixed with colorants, antistatic agents, antioxidants, heat stabilizers, ultraviolet stabilizers, ultraviolet absorbers, foaming agents, flame retardants, flame retardant additives, rust inhibitors, and mold release agents (including metal salts or esters of fatty acids with 18 to 30 carbon atoms, such as stearic acid and lycine, and polyolefin waxes such as polyethylene) as optional components. These additives are not essential components. For example, they are preferably in the range of 0.01 parts by weight or more, more preferably 1000 parts by weight or less, more preferably 10 parts by weight or less, and even more preferably 10 parts by weight or less, relative to 100 parts by weight of thermoplastic resin (A). They can be appropriately adjusted according to the purpose and use without impairing the effects of the present invention.

[0070] Another embodiment of the method for manufacturing the friction component of the present invention is a method for manufacturing a friction component, characterized in that,

[0071] It is a method for manufacturing a friction component that includes at least a friction material and a back plate supporting the friction material.

[0072] The manufacturing method includes the following steps: in a mold in which the back plate is inserted, a resin composition is melted and molded at a temperature above the softening flow temperature of the thermoplastic resin (A) to form a friction material.

[0073] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0074] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition. This will be explained in detail below.

[0075] The backplate used in this embodiment is not particularly limited in its composition; for example, resin components, metal components, ceramic components, etc., can be used.

[0076] In this embodiment, there are no particular limitations on the resin components that can be applied to the backplate. Components made of known resin compositions can be used as long as the effects of the present invention are not impaired. Examples of resin compositions that include the following resins: thermoplastic resins, such as polyester resin, polyamide resin, polyimide resin, polyetherimide resin, polycarbonate resin, polyphenylene ether resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polyaryl sulfide resin, polyetherketone resin, polyaryl ester resin, polyethylene resin, polypropylene resin, polytetrafluoroethylene resin, polydifluoroethylene resin, polystyrene resin, ABS resin, phenolic resin, polyurethane resin, liquid crystal polymers, etc.; epoxy resins, such as bisphenol type epoxy resin, phenolic varnish type epoxy resin, epoxy resin having a polyarylene ether structure, epoxy resin having an alicyclic structure and an aromatic structure in the repeating unit, etc.; silicone resins, such as condensation type silicone resin, addition type silicone resin, etc.; curable resins, such as phenolic varnish type phenolic resin, bisphenol type phenolic resin, etc. These resins can be used alone or in combination. Furthermore, the thermoplastic elastomers, silane coupling agents, fillers, additives, etc., described above can be mixed in as any component. When using thermosetting resins, curing agents (e.g., amine-type curing agents, phenolic resin-type curing agents, acid anhydride-type curing agents, latent curing agents, etc.) and curing accelerators (e.g., phosphorus compounds, tertiary amines, imidazoles, organic acid metal salts, Lewis acids, amine complex salts, etc.) are also possible. Among these, polyetheretherketone resins, polyarylene sulfide resins, and polyphenylene ether resins are preferred from the viewpoints of heat resistance, dimensional stability, and processability.

[0077] In this embodiment, there are no particular limitations on the metal components that can be applied to the back panel, as long as they do not impair the effects of the present invention, and known metal components can be used. Examples include aluminum, copper, stainless steel, magnesium, iron, titanium, or alloys containing these elements. More specifically, examples include iron; alloys such as stainless steel and steel, which are mainly composed of iron (20% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass), and which also contain elements such as carbon, silicon, manganese, chromium, tungsten, molybdenum, phosphorus, titanium, vanadium, nickel, zirconium, and boron (hereinafter referred to as ferroalloys); aluminum; alloys mainly composed of aluminum and also containing copper, manganese, silicon, magnesium, zinc, and nickel (hereinafter referred to as aluminum alloys); magnesium; alloys mainly composed of magnesium and also containing elements such as zinc, aluminum, and zirconium (hereinafter referred to as magnesium alloys); copper; alloys mainly composed of copper and also containing zinc, tin, phosphorus, nickel, magnesium, silicon, and chromium (hereinafter referred to as copper alloys); and titanium; alloys mainly composed of titanium and also containing copper, manganese, silicon, magnesium, zinc, and nickel (hereinafter referred to as titanium alloys). Among these, iron, ferroalloys, aluminum alloys, magnesium alloys, copper alloys, and titanium alloys are more preferred, and ferroalloys, aluminum alloys, and magnesium alloys are even more preferred. Especially from the perspective of strength and availability, iron, iron alloys, and aluminum alloys are preferred.

[0078] In this embodiment, there are no particular limitations on the ceramic components that can be applied to the backplate, as long as they do not impair the effects of the present invention, and components made of known ceramics can be used. Examples include oxide ceramics such as alumina, zirconium oxide, and barium titanate; hydroxide ceramics such as hydroxyapatite; carbide ceramics such as silicon carbide; and nitride ceramics such as silicon nitride. Among these, zirconium oxide and silicon carbide are preferred from the viewpoint of toughness and ease of acquisition.

[0079] Furthermore, the components used for the backplate can also be surface-roughened. Surface roughening methods can be well-known, such as (1) impregnation with an corrosive aqueous solution or suspension, (2) anodizing, and (3) mechanical cutting using sandblasting or laser processing. Among these, for metal components, the preferred methods for surface roughening are (1) impregnation with an corrosive aqueous solution or suspension and (2) anodizing; for resin or ceramic components, the preferred methods are (3) mechanical cutting using sandblasting or laser processing. The surface roughness of the roughened backplate is not particularly limited, but an arithmetic mean roughness (Ra) of 5 μm or more is preferred.

[0080] Furthermore, a primer layer can also be formed on the surface of metal parts that have undergone surface treatment. There are no particular limitations on the materials constituting the primer layer, but it is typically composed of a primer resin material containing resin components. There are no particular limitations on the primer resin material; known materials can be used. Specifically, examples include known polyolefin primers, epoxy primers, and polyurethane primers. There are no particular limitations on the method of forming the primer layer; for example, a solution or emulsion of the primer resin material can be applied to the surface-treated metal part to form the primer layer. Examples of solvents used in preparing the solution include toluene, methyl ethyl ketone (MEK), and dimethylformamide (DMF). Examples of media used as emulsions include aliphatic hydrocarbon media and water.

[0081] The process of forming a friction material by melting and molding a resin composition into a mold in which the backplate is inserted, at a temperature above the softening flow temperature of the thermoplastic resin (A), is that the process involves inserting the backplate into the mold of an injection molding machine and then injection molding the backplate using the resin composition; this is known as the insertion molding process. There are no particular limitations on the equipment and manufacturing method of the insertion molding process; commercially available equipment can be used, or conventional methods can be followed.

[0082] The manufacturing method of the friction component in this invention may include an annealing process for the friction component. The annealing process is optimized based on the application or shape of the friction component, but the annealing temperature is preferably above the glass transition temperature of the thermoplastic resin (A), preferably above that glass transition temperature +10°C, and more preferably above that glass transition temperature +30°C. The annealing time is not particularly limited, but is preferably 0.5 hours or more, more preferably 1 hour or more. On the other hand, it is preferably 10 hours or less, more preferably 8 hours or less. Within such a range, deformation of the resulting molded article can be reduced, which is therefore preferable. The annealing process can be performed in air, but is preferably performed in an inert gas such as nitrogen.

[0083] [Friction Components]

[0084] The friction component of the present invention is characterized in that,

[0085] It is a friction component that includes at least a friction material and a back plate supporting the friction material.

[0086] The friction material and the backing plate are formed by melting and molding a resin composition above the softening flow temperature of the thermoplastic resin (A).

[0087] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0088] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

[0089] Furthermore, another embodiment of the friction component of the present invention is a friction component characterized in that,

[0090] It includes at least a friction material and a backing plate that supports the friction material.

[0091] The friction material is formed by melting and molding a resin composition above the softening flow temperature of thermoplastic resin (A).

[0092] The back plate is selected from at least one of the following: metal components and ceramic components.

[0093] The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components.

[0094] The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

[0095] Furthermore, while there are no particular limitations on the coefficient of friction of the friction component in this embodiment, both the maximum static coefficient of friction and the dynamic coefficient of friction are preferably 0.20 to 1.00, more preferably 0.30 to 0.80, and even more preferably 0.35 to 0.70. Within this range, the friction component exhibits excellent balance in terms of friction characteristics, wear resistance, and acoustic vibration characteristics, and is therefore preferred. The difference between the maximum static coefficient of friction and the dynamic coefficient of friction is preferably 0.50 or less, more preferably 0.30 or less, and even more preferably 0.25 or less. Within this range, the friction component exhibits excellent performance in terms of friction characteristics and acoustic vibration characteristics, and is therefore preferred. Specifically, when the difference between the maximum static coefficient of friction and the dynamic coefficient of friction is large, the friction behavior of the friction component becomes unstable during use, easily generating vibration and noise.

[0096] The friction component of this embodiment is characterized by excellent frictional properties and wear resistance, making it particularly suitable for braking applications such as brake components and clutch components. Specifically, it can be appropriately used in components such as electromagnetic brakes, electromagnetic clutches, disc brakes, drum brakes, wheel rim brakes, servo brakes, roller brakes, and band brakes. These components can be applied to braking systems in various fields, including automobiles, motorcycles, bicycles, industrial machinery, agricultural machinery, railway vehicles, aircraft, elevators, and mobile devices.

[0097] Example

[0098] The following description uses examples and comparative examples, but the invention is not limited to these examples. Furthermore, unless otherwise stated, "%" and "parts" are based on mass.

[0099] <Examples 1-7, 9 and Comparative Examples 1-2>

[0100] The compounding of each material was carried out according to the composition and compounding amount shown in Table 1. Subsequently, these compounded materials were put into a twin-screw extruder with an exhaust port, "TEX-30α (product name)" manufactured by Japan Steel Works, Ltd., and melt-kneaded at a resin component discharge rate of 30 kg / hr, a screw rotation speed of 200 rpm, and a set resin temperature of 310°C to obtain pellets of the resin composition. The glass fiber was introduced from the side feeder (S / T ratio 0.5), and the other materials were first uniformly mixed in a drum mixer and then introduced from the top feeder. The obtained resin composition pellets were dried in a Geer oven at 140°C for 2 hours. The obtained pellets were supplied to an injection molding machine (SE-75D-HP) manufactured by Sumitomo Heavy Industries with a set barrel temperature of 310°C, and injection molding was carried out using a molding die with a mold temperature adjusted to 140°C (a ring-shaped molded product with an inner diameter of 45 mm and an outer diameter of 60 mm). During this process, a back plate (a disc-shaped one with a diameter of 60 mm) made of the material shown in Table 1 was placed in the mold in advance, and insert molding was carried out on both sides of the back plate to obtain a friction member. In addition, when using a resin member as the back plate, it was supplied to an injection molding machine (SE-75D-HP) manufactured by Sumitomo Heavy Industries with a set barrel temperature of 310°C, and injection molding was carried out using a molding die with a mold temperature adjusted to 140°C (a disc-shaped molded product with a diameter of 60 mm and a thickness of 3 mm) to produce it. It should be noted that the material of Comparative Example 1 had poor processability during the manufacture of the twin-screw extruder, and pellets could not be obtained.

[0101] <Example 8>

[0102] Pellets were produced in the same manner as above, and the obtained pellets were supplied to an injection molding machine (SE-75D-HP) manufactured by Sumitomo Heavy Industries with a set barrel temperature of 310°C, and injection molding was carried out using a molding die with a mold temperature adjusted to 140°C (a molded product with a ring-shaped friction material having an inner diameter of 45 mm and an outer diameter of 60 mm on both sides of a disc-shaped back plate with an outer diameter of 60 mm), and the friction material and the back plate were integrally molded (Japanese: 一括成形) to obtain a friction member.

[0103] <Evaluation>

[0104] (1) Evaluation of the coefficient of friction

[0105] A hole with a horizontal dimension of 10 mm and a vertical dimension of 10 mm was drilled in the center of the friction members obtained in each of the examples and comparative examples to obtain test pieces. The test pieces obtained were sandwiched between two annular plates made of S-45C with an outer diameter of 70 mm, an inner diameter of 35 mm, and a thickness of 1 mm, and a clamping force of 0.1 MPa was applied using a fixture to obtain test components. According to "5.4 Torque Test" in JIS B 1404-2:2005 "Electromagnetic Clutches and Electromagnetic Brakes - Part 2: Test Methods", rotational torque was gradually applied through the hole of the test component, and the torque immediately before rotation of the test component was measured as the static friction torque, and the torque after rotation was measured as the dynamic friction torque. Based on each torque value, the maximum static friction coefficient, dynamic friction coefficient, and the difference between the maximum static friction coefficient and the dynamic friction coefficient were calculated.

[0106] [Table 1]

[0107]

[0108] In addition, the compounding ratios of the compounding components in Table 1 used the following compositions.

[0109] A-1: PPS resin, linear type, melt viscosity (V6) 7 Pa·s

[0110] A-2: PPS resin, linear type, melt viscosity (V6) 15 Pa·s

[0111] A-3: PPS resin, linear type, melt viscosity (V6) 30 Pa·s

[0112] A-4: PPS resin, linear type, melt viscosity (V6) 50 Pa·s

[0113] B-1: Glass fiber, "T-717H" manufactured by Nippon Electric Glass Co., Ltd.

[0114] B-2: Calcium carbonate, "Calcium Carbonate Grade 1" manufactured by Sankyo Flour Milling Co., Ltd.

[0115] C-1: Graphite, "CNP15" manufactured by Ito Graphite Co., Ltd.

[0116] D-1: Thermoplastic elastomer, ethylene-glycidyl methacrylate-methyl methacrylate copolymer "BONDFAST 7L" manufactured by Sumitomo Chemical Co., Ltd.

[0117] E-1: SUS304

[0118] E-2: A5052

[0119] Manufacture of PPS resin

[0120] <PPS resin A-1>

[0121] In a 150 L autoclave with stirring blades connected to a pressure gauge, thermometer, condenser, decanter, and distillation column, 35.839 kg (244 mol) of p-dichlorobenzene (hereinafter referred to as DCB), 4.332 kg (44 mol) of N-methylpyrrolidone (NMP), 27.300 kg of a 47.23 mass% aqueous NaSH solution (230 mol as NaSH), and 18.321 kg of a 49.21 mass% aqueous NaOH solution (225 mol as NaOH) were added. While stirring, the temperature was raised to 173 °C in a nitrogen atmosphere over 5 hours. After distilling off 26.760 kg of water, the autoclave was sealed. The DCB distilled off by azeotropic distillation during dehydration was separated by the decanter and returned to the autoclave at any time. After the dehydration process ended, the autoclave was in a state where anhydrous sodium sulfide composition was dispersed in DCB. After the dehydration process ended, the internal temperature was cooled to 160 °C, 45.440 kg (458 mol) of NMP was added, and the temperature was raised to 185 °C. When the pressure reached 0.00 MPa, the valve connecting to the distillation column was opened, and the internal temperature was raised to 200 °C over 1 hour. At this time, control was performed by cooling and valve opening to keep the temperature at the outlet of the distillation column below 110 °C. The mixed vapor of distilled DCB and water was condensed in the condenser and separated by the decanter, and the DCB was returned to the autoclave. The amount of distilled water was 180 g. The temperature was raised from 200 °C to 230 °C over 3 hours, stirred for 1 hour, then raised to 250 °C and stirred for 1 hour. After the reaction ended, the bottom valve of the autoclave was opened, and it was flash-evaporated into a 150 L vacuum stirring dryer with stirring blades to remove NMP. Subsequently, it was stirred at 150 °C under reduced pressure for 4 hours to fully remove NMP, obtaining a mixture of powdery PPS resin and salts. 90 kg of ion-exchanged water at 70 °C was added to 30 kg of the obtained crude PPS mixture, stirred for 30 minutes and then filtered. 90 kg of ion-exchanged water at 70 °C was added to the filter cake after filtration for filter cake washing. Then, the obtained water-containing filter cake and 60 kg of ion-exchanged water were charged into a 100 L autoclave with stirring blades. While stirring, the temperature was raised to 230 °C over 2 hours, stirred for 30 minutes for extraction treatment, and cooled to room temperature. All the obtained mixture was filtered, and 90 kg of ion-exchanged water at 70 °C was added to the filter cake after filtration for filter cake washing. Then, it was dried at 120 °C for 4 hours to obtain white powdery PPS resin.

[0122] <PPS resin A-2>

[0123] Except for using 34.824 kg (237 mol) of p-dichlorobenzene (p-DCB), it was manufactured by the same steps as A-1.

[0124] <PPS resin A-3>

[0125] It was produced by the same procedure as A-1 except that 33.810 kg (230 mol) of p-dichlorobenzene (p-DCB) was used.

[0126] <PPS resin A-4>

[0127] It was produced by the same procedure as A-1 except that 33.472 kg (228 mol) of p-dichlorobenzene (p-DCB) was used.

[0128] As can be seen from Table 1, the friction members of the examples have a friction material composed of a thermoplastic resin composition and exhibit excellent performance in terms of the maximum static friction coefficient and the dynamic friction coefficient. In Comparative Example 1 where the melt viscosity of the thermoplastic resin was too high, the processability was poor and it was difficult to produce the resin composition. In Comparative Example 2 where the blending amount of the thermoplastic resin was excessive, the difference between the maximum static friction coefficient and the dynamic friction coefficient was large, resulting in unstable friction behavior of the friction member and easy generation of vibration.

Claims

1. A method for manufacturing a friction component, characterized in that, It is a method for manufacturing a friction component that includes at least a friction material and a back plate supporting the friction material. The manufacturing method comprises the following steps: melting and molding a resin composition above the softening flow temperature of the thermoplastic resin (A) to form the friction material and the backing plate within the same molding cycle. The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components. The amount of the thermoplastic resin (A) is less than 50 parts by mass relative to 100 parts by mass of the resin composition, wherein the melt viscosity (V6) is the melt viscosity after holding for 6 minutes with a load of 1.96 MPa applied at a temperature of 20°C above the softening flow temperature of the thermoplastic resin (A) using a rheometer, using an orifice with a length-to-diameter ratio of 10 / 1.

2. A method for manufacturing a friction component, characterized in that, It is a method for manufacturing a friction component that includes at least a friction material and a back plate supporting the friction material. The manufacturing method includes the following steps: in a mold in which the back plate is inserted, a resin composition is melted and molded at a temperature above the softening flow temperature of the thermoplastic resin (A) to form a friction material. The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components. The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

3. The method for manufacturing the friction component as described in claim 1 or 2, wherein, The thermoplastic resin (A) is at least one selected from the group consisting of polybutylene terephthalate, polyamide-6T, polyamide-9T, polyamide-10T, polyamide MXD6, and polyarylene sulfide resin.

4. The method for manufacturing the friction component as described in claim 1 or 2, wherein, The resin composition is also formulated with a solid lubricant (C).

5. The method for manufacturing the friction component as described in claim 1 or 2, wherein, The resin composition is also formulated with an organic filler material (D).

6. The method for manufacturing the friction component as described in claim 2, wherein, The backplate is selected from at least one of resin components, metal components, and ceramic components.

7. A friction component, characterized in that, It is a friction component that includes at least a friction material and a back plate supporting the friction material. The friction material and the backing plate are formed by melting and molding a resin composition above the softening flow temperature of the thermoplastic resin (A). The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components. The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

8. A friction component, characterized in that, It is a friction component that includes at least a friction material and a back plate supporting the friction material. The friction material is formed by melting and molding a resin composition above the softening flow temperature of thermoplastic resin (A). The back plate is selected from at least one of the following: metal components and ceramic components. The resin composition comprises a thermoplastic resin (A) with a melt viscosity (V6) of less than 30 Pa·s and a flow softening temperature of more than 130°C, and an inorganic filler (B) as essential components. The amount of the thermoplastic resin (A) is 50 parts by weight or less relative to 100 parts by weight of the resin composition.

9. The friction component as claimed in claim 6 or 7, wherein, The thermoplastic resin (A) is at least one selected from the group consisting of polybutylene terephthalate, polyamide-6T, polyamide-9T, polyamide-10T, polyamide MXD6, and polyarylene sulfide resin.

10. The friction component as claimed in claim 6 or 7, wherein, The resin composition is also formulated with a solid lubricant (C).

11. The friction component as claimed in claim 6 or 7, wherein, The resin composition is also formulated with an organic filler material (D).

12. A method of using the friction component as a braking component according to claim 6 or 7.

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