Resin composition, brake rotor, set for producing brake rotor, brake rotor manufacturing method, and brake

Abstract

A resin composition used for coating the sliding surface of a brake rotor, the resin composition containing: at least one compound selected from the group consisting of titanium compounds, magnesium compounds, and lithium compounds; and an epoxy resin or a precursor thereof.

Description

Resin composition, brake rotor, brake rotor manufacturing set, brake rotor manufacturing method, and brake

[0001] The present disclosure relates to a resin composition, a brake rotor, a brake rotor manufacturing set, a brake rotor manufacturing method, and a brake.

[0002] Disc brakes used in automobiles, motorcycles, etc. are components in which a disc rotor is sandwiched between two brake linings, and braking is performed by the friction therebetween.

[0003] Brake rotors are generally made of cast iron or stainless steel, and the surfaces where the brake lining and brake rotor slide are finished by grinding. As an example, a structural diagram of a brake rotor is shown in Figure 1. In the brake rotor 10 shown in Figure 1, the sliding surface 1 is renewed by sliding with the brake pad during brake use, but rust forms on the rotor side surface 2 and the fastening surface 3. For this reason, a highly heat-resistant, high-molecular-weight resin-based coating composition, as disclosed in Patent Document 5, is sometimes applied to the rotor side surface 2 or the fastening surface 3.

[0004] Rust can develop on the sliding surfaces of brake rotors between their manufacture and use in a vehicle. Rust can cause the brake pads and the brake rotor to stick together, making it difficult for the brake rotor to rotate. A difference in the thickness of rust on the brake rotor between the areas covered by the brake pads and other areas can also cause vibrations known as brake judder. For this reason, as described in Patent Document 1, the sliding surfaces of brake rotors are sometimes subjected to a dacrotizing treatment or the like.

[0005] Furthermore, in order to make the sliding surfaces of brake rotors in use less susceptible to rust, Patent Document 2 proposes nitriding the surfaces of brake rotors to enhance rust prevention. Furthermore, Patent Documents 3 and 4 propose applying a rust prevention coating material such as a reducing compound to brake rotors and the like to prevent rust.

[0006] Patent Document 6 proposes applying a coating agent containing a highly heat-resistant resin and a solid lubricant to disc brake components such as disc rotors, and the coating agent is applied to, for example, the sliding surface of the disc rotor.

[0007] Japanese Patent Publication No. 2002-323073 Japanese Patent Publication No. 2016-164439 Japanese Patent Publication No. 2004-510924 Japanese Patent Publication No. 5706197 Japanese Patent Publication No. 2017-508023 International Publication No. 2005 / 080515

[0008] The braking force of a disc brake is generated by the friction between the brake rotor and brake lining, but initially (for example, when new), the two components do not bond well together. Normally, the initial state of the brake rotor surface is pure iron, but as it is used, a transfer film from the friction material forms on the surface layer, stabilizing the friction coefficient, wear, etc. Therefore, it takes several hundred braking cycles to achieve the originally designed braking friction force.

[0009] In Patent Document 1, a brake rotor is subjected to a dacrotized treatment for the purpose of preventing rust on the sliding surface from manufacture to vehicle use. Patent Documents 5 and 6 describe coating with a polymeric resin-based paint, with the components remaining on the brake rotor surface for a long period of time. In these cases, it takes longer for the original friction characteristics achieved by the brake rotor and brake lining to be realized than in an untreated case. Furthermore, the coated components may remain on the sliding surface, destabilizing the friction coefficient and generating abnormal noise. It is desirable not to apply the compositions described in Patent Documents 5 and 6, which have excellent coating properties, to the sliding surface. Since the sliding surface changes to a new surface through friction with the brake pad during brake use, rust prevention from manufacture to vehicle use is more important than during use. Therefore, a resin composition that exhibits rust prevention effects on the sliding surface from manufacture to vehicle use and can be used to produce a brake rotor with excellent stability of the initial friction coefficient during brake use is desirable.

[0010] Anti-rust coating materials such as nitriding coatings as in Patent Document 2 and reducing compounds as in Patent Documents 3 and 4 initially result in poor compatibility between the brake rotor and brake lining, just like brake rotors without these coatings. Therefore, to achieve the originally designed braking friction force, braking must be performed several hundred times or more. Furthermore, while the nitriding coating maintains its frictional properties for a long period of time, the frictional properties change significantly when the coating is worn off and the internal cast iron is exposed. Another problem is the high processing costs of dacrotizing and nitriding.

[0011] In recent years, as electric vehicles have become more common and battery mass has increased, brakes have also become larger to ensure braking force in emergencies. However, regenerative braking reduces the brake load during normal operation. This has created a problem in that it takes time for the braking force to reach the designed braking force. Meanwhile, as autonomous driving of automobiles progresses, if a constant braking force cannot be obtained at all times, the vehicle will not decelerate as designed, which is an even greater problem.

[0012] The present disclosure has been made in consideration of the above-described conventional circumstances, and aims to provide a resin composition, a brake rotor manufacturing set, and a brake rotor manufacturing method that enable the manufacture of a brake rotor that has excellent rust prevention effects on the sliding surface and excellent stability of the initial friction coefficient from the time of manufacture to the time of use in a vehicle. The present disclosure also aims to provide a brake rotor that has excellent rust prevention effects and excellent stability of the initial friction coefficient, and a brake including the same.

[0013] Specific means for achieving the above object are as follows. <1> A resin composition for use in coating a sliding surface of a brake rotor, the resin composition comprising at least one compound selected from the group consisting of a titanium compound, a magnesium compound, and a lithium compound, and an epoxy resin or a precursor thereof. <2> The resin composition according to <1>, wherein the compound is a titanium compound. <3> The resin composition according to <1> or <2>, wherein the titanium compound is at least one selected from the group consisting of titanium oxide and titanium black. <4> The resin composition according to any one of <1> to <3>, wherein the content of the compound is 25% by mass to 90% by mass based on the total solid content. <5> The resin composition according to any one of <1> to <4>, wherein the epoxy resin or precursor thereof has an epoxy equivalent of 1000 g / eq or less. <6> The resin composition according to any one of <1> to <5>, wherein the epoxy resin or precursor thereof includes a bisphenol-type epoxy resin or a precursor thereof. <7> A brake rotor, the sliding surface of which is provided with a metal-containing layer formed from the resin composition according to any one of <1> to <6>. <8> A brake rotor manufacturing set comprising: at least one compound selected from the group consisting of a titanium compound, a magnesium compound, and a lithium compound; an epoxy resin or a precursor thereof; and a rotor member. <9> A method for manufacturing a brake rotor using the brake rotor manufacturing set according to <8>, comprising forming a metal-containing layer by applying a resin composition containing the compound and the epoxy resin or a precursor thereof to a sliding surface of the rotor member. <10> A brake comprising the brake rotor according to <7> and a brake pad. <11> The brake according to <10>, wherein the metal-containing layer has a thickness of 1 μm to 100 μm. <12> The brake according to <10> or <11>, wherein the brake rotor is made of cast iron and has been subjected to at least one surface treatment of grinding, polishing, and machining. <13> The brake according to any one of <10> to <12>, wherein the brake pad is a non-asbestos organic material pad.

[0014] According to one aspect of the present disclosure, it is possible to provide a resin composition, a brake rotor manufacturing set, and a brake rotor manufacturing method that can manufacture a brake rotor that has excellent rust prevention effect and stability of the initial friction coefficient from the time of manufacture to the time of use in a vehicle. Also, according to one aspect of the present disclosure, it is possible to provide a brake rotor that has excellent rust prevention effect and stability of the initial friction coefficient, and a brake including the same.

[0015] FIG. 2 is a diagram illustrating the configuration of a brake rotor.

[0016] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure.

[0017] In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another staged numerical range. Furthermore, in numerical ranges described in the present disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple corresponding substances. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, particles corresponding to each component may include multiple types of particles. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified. In the present disclosure, the term "layer" includes cases where the layer is formed over the entire area when the area where the layer is present is observed, as well as cases where the layer is formed only in a part of the area. The average particle size of the particles refers to the 50% (median) diameter (D50) determined from the volume distribution of particle size distribution measured with a laser diffraction / scattering particle size distribution analyzer. The average particle size can be measured, for example, with an LA-920 (manufactured by Horiba, Ltd.).

[0018] [Resin Composition] The resin composition of the present disclosure contains at least one compound selected from the group consisting of titanium compounds, magnesium compounds, and lithium compounds (hereinafter also referred to as a "specific metal compound"), and an epoxy resin or a precursor thereof, and is a composition used for coating a brake rotor sliding surface.

[0019] The resin composition of the present disclosure is used for coating the sliding surface of a brake rotor, and is preferably used to form a metal-containing layer on the sliding surface of a cast iron or stainless steel brake rotor substrate.

[0020] The specific metal compound preferably includes a titanium compound, and more preferably is a titanium compound.

[0021] The specific metal compound may be a compound containing at least one cation selected from the group consisting of titanium cations, magnesium cations, and lithium cations. Examples include hydroxides, carbonates, sulfates, halides, oxides, complex acid salts such as titanium complex acid salts, and organometallic compounds such as titanium black and organometallic compounds containing titanium. The specific metal compound is preferably at least one selected from the group consisting of titanium oxide and titanium black. Titanium oxide is preferred from the viewpoint of ease of availability, and titanium black is preferred from the viewpoint of black painting.

[0022] 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 trichloride, titanium tetrachloride, magnesium chloride, magnesium bromide, lithium chloride, and lithium bromide. Examples of oxides include titanium oxide and magnesium oxide. Examples of titanium complex salts include M ｘ O (titanium oxide) ｙ The titanium complex salt is represented by the general formula: ｘ O is an oxide containing a cation represented by M, and x and y are integers. Examples of titanium composite salts include lithium titanate, magnesium titanate, lithium potassium titanate, titanocene, potassium titanate, and lithium potassium titanate. Examples of organometallic compounds containing titanium include titanocene and bis(η5-cyclopentadienyl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium.

[0023] The specific metal compound is preferably a titanium compound, and from the viewpoint of shortening the friction stabilization time, the titanium compound is preferably at least one selected from the group consisting of titanium oxide, titanium black, lithium titanate, potassium titanate, magnesium titanate, lithium potassium titanate, and titanocene.

[0024] The specific metal compound may be in the form of particles. In this case, 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.

[0025] The content of the specific metal compound is preferably 25% by mass to 90% by mass, more preferably 30% by mass to 80% by mass, and even more preferably 40% by mass to 70% by mass, based on the total solid content.

[0026] The resin composition of the present disclosure contains an epoxy resin or a precursor thereof. By using the epoxy resin or a precursor thereof in combination with a specific metal compound, it is possible to suppress powder shedding of the specific metal compound. This makes it possible to favorably maintain anti-rust effects in brake rotors manufactured using the resin composition of the present disclosure.

[0027] The above-mentioned epoxy resin or its precursor is preferably dissolved in a liquid that dissolves or disperses the powder.

[0028] Specific examples of epoxy resins or precursors thereof include bisphenol-type epoxy resins such as bisphenol A-type and bisphenol F-type, phenol novolac-type, cresol novolac-type, Xylok-type, aliphatic-type, glycidylamine-type, naphthalene-type, or biphenol-type epoxy resins or precursors thereof. From the viewpoints of easy availability, excellent handleability, and the resin composition being applicable to a variety of coating forms, bisphenol-type epoxy resins or precursors thereof are preferred, and bisphenol A-type or bisphenol F-type epoxy resins or precursors thereof are more preferred. One type of epoxy resin or precursor thereof may be used alone, or two or more types may be used in combination.

[0029] From the viewpoint of thermal curing, the epoxy equivalent of the epoxy resin or its precursor is preferably 1000 g / eq or less, more preferably 100 g / eq to 950 g / eq, and even more preferably 150 g / eq to 900 g / eq.

[0030] From the viewpoint of achieving superior rust prevention effects on sliding surfaces from manufacture to vehicle use and superior stability of the initial coefficient of friction, the epoxy equivalent of the epoxy resin or its precursor is preferably 900 g / eq or less, more preferably 800 g / eq or less, even more preferably 600 g / eq or less, and particularly preferably 500 g / eq or less. The lower limit of the epoxy equivalent of the epoxy resin or its precursor is not particularly limited, and may be 100 g / eq or more, or may be 150 g / eq or more. When the epoxy equivalent of the epoxy resin or its precursor is 900 g / eq or less, fluctuations in the initial coefficient of friction during brake use are suppressed. This is because the epoxy equivalent is not too high, and the adhesion of the resin composition applied to the sliding surface is not too high. It is presumed that this allows the resin composition to exhibit rust prevention effects on sliding surfaces from manufacture to vehicle use, while easily removing the applied resin composition during brake use, thereby suppressing fluctuations in the initial coefficient of friction during brake use.

[0031] The resin composition of the present disclosure is preferably curable after application from the viewpoints of preventing powder falling off after application and heat resistance. Curing may be either heat curing or light curing, and heat curing is preferred from the viewpoint of simplicity of the curing device.

[0032] The resin composition of the present disclosure may contain a curing agent, a curing accelerator, and the like.

[0033] Examples of curing agents include phenolic, acid anhydride, and amine curing agents. For example, phenolic curing agents include phenol novolac resin, cresol novolac resin, and phenol aralkyl resin. Acid anhydride curing agents include docecenyl succinic anhydride, polyazelaic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride. Amine curing agents include dicyandiamide and melamine. Dicyandiamide is particularly preferred because it can be used in a variety of coating applications.

[0034] From the viewpoint of sufficient curing, the ratio of the number of equivalents of reactive groups contained in the epoxy resin or its precursor to the number of equivalents of reactive groups contained in the curing agent is preferably 0.4 to 2.0, and more preferably 0.6 to 1.2.

[0035] Examples of the curing accelerator include tertiary amines, imidazoles, and phosphorus compounds. Examples of the tertiary amines include benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo[5.4.0]undec-7-ene. Examples of the imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole, 1-(2-cyanoethyl)-2-phenylimidazole, and 2-heptadecylimidazole. Examples of the phosphorus compounds include triphenylphosphine. These are appropriately selected depending on the curing temperature, and imidazoles are preferred.

[0036] From the viewpoint of smoothly progressing curing and obtaining a cured product excellent in strength, the content of the curing accelerator is preferably 0.05% by mass to 5% by mass, and more preferably 0.1% by mass to 2% by mass, relative to the total mass of the epoxy resin or its precursor.

[0037] The resin composition of the present disclosure may or may not contain other components in addition to the specific metal compound, the epoxy resin or its precursor, the curing agent, and the curing accelerator. Examples of other components include other resins other than the epoxy resin or its precursor, or their precursors, liquids, polymerization initiators such as thermal polymerization initiators and photopolymerization initiators, crosslinking agents, sensitizers, friction modifiers, viscosity modifiers, elastic modulus modifiers, surfactants, leveling agents, metal deactivators, colorants such as charcoal, and fragrances.

[0038] Examples of other resins include phenolic resins, urethane resins, fluororesins, polyester resins, amide resins, amide-imide resins, imide resins, melamine resins, urethane resins, phenoxy resins, silicone resins, silicic acid resins, acrylic resins, and olefin resins. Precursors of other resins include precursors of these resins. The other resins or their precursors may be used independently, either individually or in combination.

[0039] From the viewpoint of forming a metal-containing layer having excellent uniformity in film thickness, the resin composition of the present disclosure preferably contains a liquid that dissolves or disperses a specific metal compound, a resin, etc. The total content of the specific metal compound may be adjusted appropriately depending on whether the specific metal compound is soluble in the liquid or dispersed in the liquid.

[0040] The total content of the specific metal compounds may be 1% by mass to 80% by mass, or 5% by mass to 70% by mass, relative to the total amount of the resin composition, from the viewpoints of enabling spray coating and facilitating adjustment of the film thickness.

[0041] Examples of the liquid include water, alcohol-based solvents, glycol-based solvents, ester-based solvents, ketone-based solvents, ether-based solvents, and aromatic solvents, and more specific examples include diethyl ether, dimethyl ether, acetone, methyl ethyl ketone, diisobutyl ketone, ethyl acetate, methanol, ethanol, toluene, xylene, N-methylpyrrolidone, dimethylacetamide, and 1-methoxy-2-propanol.

[0042] When the resin or its precursor contained in the resin composition is a thermosetting or photocurable material, the resin composition of the present disclosure may contain a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator.

[0043] As the polymerization initiator, commercially available radical or cationic polymerization initiators can be used, and organic peracids, azo-based radical polymerization initiators, etc. may also be used. As a radical photopolymerization initiator, bis(η5-cyclopentadienyl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium (e.g., Irgacure 784 manufactured by IGM Resins) may also be used. This material can serve as both a photopolymerization initiator and a titanium compound.

[0044] The resin composition of the present disclosure may be a liquid material (e.g., a liquid composition) or a powder material. A liquid material is preferable because it is possible to form a highly uniform metal-containing layer and various application methods can be used. Methods for applying the powder material to the brake rotor substrate include powder application by spraying. Methods for applying the liquid material to the brake rotor substrate include using a dispenser, spraying, cast coating, spin coating, etc.

[0045] The ratio of the total amount of the epoxy resin and its precursor to the total amount of the specific metal compound (epoxy resin and its precursor / specific metal compound) may be 0.2 to 10, 0.5 to 8, or 1 to 5 in terms of mass ratio, from the viewpoint of suppressing powder falling and fading.

[0046] [Brake rotor] The brake rotor of the present disclosure has a metal-containing layer formed from the resin composition of the present disclosure on its sliding surface. The brake rotor of the present disclosure has excellent rust prevention effects and stability of the initial friction coefficient. The reason for this is presumed to be as follows: The titanium compound, magnesium compound, or lithium compound penetrates into the surface of the brake rotor and forms a dense metal-containing layer on the sliding surface, thereby achieving rust prevention and stability of the initial friction coefficient. From the viewpoint of facilitating the formation of a dense metal-containing layer on the sliding surface from the low temperature range at the beginning of friction, it is preferable to use a titanium compound.

[0047] Furthermore, with the brake rotor of the present disclosure, for example, the friction coefficient is stabilized from around 100°C at the start of use of the brake rotor to around 300°C, particularly around 100°C, improving wear of friction materials such as disc brake pads. As a result, wear debris can be reduced, reducing the generation of substances harmful to the environment and humans. It is also possible to reduce the use of environmental pollutants. Additionally, the addition of specific metal compounds also provides rust prevention effects during storage of the brake rotor.

[0048] The brake rotor of the present disclosure inhibits rust on the brake rotor when new, reducing the number of braking cycles required to achieve a predetermined braking force. This shortens the time required to achieve stable braking force, even in vehicles with a low braking load, such as electric vehicles.

[0049] The brake rotor of the present disclosure is a brake rotor used in, for example, automobiles, motorcycles, etc. The brake rotor may also be a disc rotor for a disc brake.

[0050] The brake rotor on which the metal-containing layer is formed is preferably made of cast iron and has been subjected to surface treatment by at least one of grinding, polishing, and machining, such as roller burnishing.

[0051] The amount of the specific metal compound contained in the metal-containing layer, i.e., the amount of the specific metal compound carried per unit area of ​​the sliding surface of the brake rotor, also depends on the density of the specific metal compound. However, from the viewpoint of preferably exhibiting the effects of the invention and reducing the amount of the specific metal compound used, for example, it is preferable to set the specific metal compound content to 0.01 mg / cm. ２ ~25 mg / cm ２ and preferably 0.2 mg / cm ２ ~12.5mg / cm ２ It is more preferable that:

[0052] By including a resin in the metal-containing layer, a specific metal compound is supported on the sliding surface, which prevents powder from falling off and allows the rust prevention effect to be maintained in an optimal manner.

[0053] The thickness of the metal-containing layer may be 1 μm to 100 μm, or 5 μm to 50 μm. When the thickness of the metal-containing layer is 1 μm or more, the rust prevention effect is suitably improved. When the thickness of the metal-containing layer is 100 μm or less, the friction stabilization time can be shortened and the resin can be prevented from turning into tar when heated, which can cause a decrease in the friction coefficient, known as fade.

[0054] The total content of the specific metal compounds may be 10% by mass to 80% by mass, or may be 20% by mass to 70% by mass, based on the total amount of the metal-containing layer.

[0055] [Set for manufacturing a brake rotor] The set for manufacturing a brake rotor of the present disclosure includes at least one compound (specific metal compound) selected from the group consisting of a titanium compound, a magnesium compound, and a lithium compound, an epoxy resin or a precursor thereof, and a rotor member.

[0056] The brake rotor fabrication set of the present disclosure is used for fabricating a brake rotor. For example, the resin composition of the present disclosure can be obtained by using a specific metal compound and an epoxy resin or a precursor thereof, and the resin composition can be applied to the sliding surface of the rotor member to form a metal-containing layer.

[0057] [Method for manufacturing a brake rotor] The method for manufacturing a brake rotor of the present disclosure is a method using the brake rotor manufacturing set of the present disclosure or the resin composition of the present disclosure, and includes applying the resin composition or a resin composition containing the compound in the brake rotor manufacturing set described above and the epoxy resin or a precursor thereof to the sliding surface of a rotor member to form a metal-containing layer.

[0058] Methods for forming a metal-containing layer on the sliding surface of a brake rotor include a method of adhering a powder containing a specific metal compound to the substrate of the brake rotor, and a method of applying a liquid composition in which the powder is dissolved or dispersed in a liquid to the substrate of the brake rotor. Examples of methods for applying the liquid composition to the substrate of the brake rotor include applying the liquid composition using a dispenser, spray, cast coating, spin coating, etc.

[0059] When a liquid composition is used, it is preferable to heat the liquid composition after application in order to evaporate the liquid. The heating temperature depends on the boiling point of the liquid in the liquid composition, but is preferably a temperature between the boiling point -30°C and the boiling point +30°C.

[0060] The brake of the present disclosure includes the brake rotor of the present disclosure and brake pads. The brake may include a disc rotor and disc brake pads, and may be a brake used in an automobile, a motorcycle, or the like.

[0061] The brake pad may be, for example, a component formed using a friction material formed by molding a friction material composition and a backing metal. A primer layer for surface modification to enhance the adhesive effect of the backing metal to the friction material, and an adhesive layer for bonding the backing metal to the friction material may be further interposed between the backing metal and the friction material. The brake pad may be a steel pad, a semi-steel pad, or an organic pad, and is preferably a non-asbestos organic pad from the viewpoint of more clearly demonstrating the effect.

[0062] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples in any way.

[0063] (Preparation of Titanium Oxide Coating Liquid-1) 2 g of anatase titanium oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2 g of bisphenol A liquid epoxy resin (trade name: EP850, manufactured by DIC Corporation, epoxy equivalent: approximately 190 g / eq), 100 mg of dicyandiamide (DICY), and 20 mg of 2-ethyl-4-methylimidazole were dissolved or dispersed in 14 g of 1-methoxy-2-propanol (solvent) to obtain a resin composition, titanium oxide coating liquid-1. Titanium oxide settles over time, but the solution was thoroughly stirred immediately before use to disperse the titanium oxide.

[0064] (Preparation of Titanium Oxide Coating Liquid-2) 2 g of anatase titanium oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2 g of bisphenol A liquid epoxy resin (trade name: JER1001, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 475 g / eq), 40 mg of dicyandiamide (DICY), and 8 mg of 2-ethyl-4-methylimidazole were dissolved or dispersed in 14 g of 1-methoxy-2-propanol (solvent) to obtain a resin composition, titanium oxide coating liquid-2. Titanium oxide settles over time, but the solution was thoroughly stirred immediately before use to disperse the titanium oxide.

[0065] (Preparation of Titanium Oxide Coating Liquid-3) 2 g of anatase titanium oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2 g of bisphenol A liquid epoxy resin (trade name: EP3050, manufactured by DIC Corporation, epoxy equivalent: approximately 800 g / eq), 24 mg of dicyandiamide (DICY), and 4.8 mg of 2-ethyl-4-methylimidazole were dissolved or dispersed in 18.2 g of 1-methoxy-2-propanol (solvent) to obtain a resin composition, titanium oxide coating liquid-2. Titanium oxide settles over time, but the solution was thoroughly stirred immediately before use to disperse the titanium oxide.

[0066] (Preparation of Titanium Oxide Coating Liquid-4) 2 g of anatase titanium oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2 g of bisphenol A liquid epoxy resin (trade name: EP4050, manufactured by DIC Corporation, epoxy equivalent: approximately 950 g / eq), 20 mg of dicyandiamide (DICY), and 4 mg of 2-ethyl-4-methylimidazole were dissolved or dispersed in 14 g of 1-methoxy-2-propanol (solvent) to obtain a resin composition, titanium oxide coating liquid-4. Titanium oxide settles over time, but the solution was thoroughly stirred immediately before use to disperse the titanium oxide.

[0067] (Preparation of Epoxy Coating Liquid) 2 g of bisphenol A liquid epoxy resin (trade name: EP850, manufactured by DIC Corporation, epoxy equivalent: approximately 190 g / eq), 100 mg of dicyandiamide (DICY), and 20 mg of 2-ethyl-4-methylimidazole were dissolved or dispersed in 14 g of 1-methoxy-2-propanol (solvent) to obtain an epoxy coating liquid.

[0068] (Preparation of Polyacrylic Acid Solution (A)) A mixed solvent of 1-methoxy-2-propanol and toluene was charged into a flask equipped with a stirrer, reflux condenser, inert gas inlet, and thermometer, and the temperature was raised to 80°C under a nitrogen gas atmosphere. While maintaining the reaction temperature at 80°C ± 2°C, methyl methacrylate / ethyl acrylate / methacrylic acid / 2,2'-azobis(isobutyronitrile) was added dropwise uniformly over 4 hours in a mass ratio of 58 / 30 / 12 / 1 so that the resin content of the resulting solution was 47.4%. After the dropwise addition, stirring was continued at 80°C ± 2°C for 6 hours to obtain an acrylic solution (A) (molecular weight 135,000).

[0069] (Preparation of polyacrylic acid-titanium oxide coating solution) 4 g of anatase titanium oxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 17 g of polyacrylic acid solution (A) (polyacrylic acid content 8 g) were dissolved or dispersed in 19.2 g of ethyl acetate (solvent) to obtain a polyacrylic acid-titanium oxide coating solution, which is a resin composition. Titanium oxide settles over time, but the solution was thoroughly stirred immediately before use to disperse the titanium oxide.

[0070] (Preparation of Test Pad) A test pad (HP69H, Resonac Inc., pad area: 60 cm) used for the friction evaluation described below was prepared. ２ ) was prepared.

[0071] [Example 1] Approximately 9 g of titanium oxide coating solution-1 was spray-coated evenly onto the outer surface of a rotor (diameter 280 mm, thickness 28 mm; the same applies to the following Examples and Comparative Examples) that had been preheated to approximately 80°C. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes and left at room temperature. When the surface temperature had dropped to approximately 80°C, approximately 9 g of titanium oxide coating solution-1 was spray-coated evenly onto the inner surface of the rotor. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes. In this manner, the brake rotor of Example 1 was produced.

[0072] [Example 2] Approximately 9 g of titanium oxide coating solution-2 was spray-coated evenly onto the outer surface of a rotor preheated to approximately 80°C. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes and left at room temperature. When the surface temperature had dropped to approximately 80°C, approximately 9 g of titanium oxide coating solution-2 was spray-coated evenly onto the inner surface of the rotor. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes. In this manner, the brake rotor of Example 2 was produced.

[0073] [Example 3] Approximately 9 g of titanium oxide coating solution-3 was spray-coated evenly onto the outer surface of a rotor preheated to approximately 80°C. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes and left at room temperature. When the surface temperature had dropped to approximately 80°C, approximately 9 g of titanium oxide coating solution-3 was spray-coated evenly onto the inner surface of the rotor. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes. In this manner, the brake rotor of Example 3 was produced.

[0074] [Comparative Example 1] Approximately 8 g of epoxy coating liquid was spray-coated evenly onto the outer surface of a rotor preheated to approximately 80°C. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes and left at room temperature. When the surface temperature had dropped to approximately 80°C, approximately 8 g of epoxy coating liquid was spray-coated evenly onto the inner surface of the rotor. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes. In this manner, the brake rotor of Comparative Example 1 was produced.

[0075] [Comparative Example 2] Approximately 20 g of polyacrylic acid-titanium oxide coating liquid was spray-coated evenly onto the outer surface of the rotor. The rotor was then heated for 10 minutes in a hot air dryer at approximately 80°C, 10 minutes in a hot air dryer at approximately 100°C, and 10 minutes in a hot air dryer at approximately 120°C, and then left at room temperature. Once the surface temperature had dropped to room temperature, approximately 20 g of polyacrylic acid-titanium oxide coating liquid was spray-coated evenly onto the inner surface of the rotor. The rotor was then heated for 10 minutes in a hot air dryer at approximately 80°C, 10 minutes in a hot air dryer at approximately 100°C, and 10 minutes in a hot air dryer at approximately 120°C, and then left at room temperature. In this manner, the brake rotor of Comparative Example 2 was produced.

[0076] [Comparative Example 3] Approximately 9 g of titanium oxide coating solution-4 was spray-coated evenly onto the outer surface of a rotor preheated to approximately 80°C. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes and left at room temperature. When the surface temperature had dropped to approximately 80°C, approximately 9 g of titanium oxide coating solution-34 was spray-coated evenly onto the inner surface of the rotor. The rotor was then heated in a hot air dryer at approximately 180°C for 30 minutes. In this manner, the brake rotor of Comparative Example 3 was produced.

[0077] (Friction evaluation) A friction evaluation test was conducted using the above-mentioned test pad, a brake rotor of each example or comparative example or an untreated rotor (diameter 280 mm, thickness 28 mm), and a brake dynamometer (manufactured by Shin Nippon Tokki Co., Ltd.) under conditions of a temperature of 20°C and a humidity of 60%.

[0078] Using the brake rotors of Examples 1 and 3, the brake rotors of Comparative Examples 2 and 3, and an untreated rotor, the braking test was repeated 100 times under the conditions shown in Table 1 to measure the friction coefficient. The results are shown in Table 1. In Comparative Example 2, the variation in the friction coefficient during one braking test was 0.2 or more, and the variation in the friction coefficient was so large that it was not possible to measure the friction coefficient. In Comparative Example 3, the variation in the friction coefficient during braking decreased from the 10th test, making it possible to measure the friction coefficient, but the variation in the friction coefficient during braking was 0.2 or more during the first and fifth tests, making it impossible to measure the friction coefficient.

[0079] Using the brake rotors of Example 1, Example 2, and Comparative Example 1, as well as an untreated rotor, the braking test was repeated 100 times under the conditions shown in Table 2 to measure the friction coefficient. The results are shown in Table 2. In Comparative Example 1, the variation in the friction coefficient during one braking test was 0.2 or more, and the variation in the friction coefficient was so large that it was not possible to measure the friction coefficient.

[0080]

[0081]

[0082] As shown in Table 1, compared to the untreated rotor, the brake rotors of Examples 1 and 3 had high friction coefficients from the initial stage and showed little change in the friction coefficient as the number of braking cycles increased. As shown in Table 2, the brake rotors of Examples 1 and 2 had high friction coefficients from the initial stage and showed relatively little change in the friction coefficient as the number of braking cycles increased, within an acceptable range. Furthermore, even when the test conditions were changed using the brake rotor of Example 1 as shown in Tables 1 and 2, a stable friction coefficient was obtained. From this, it can be inferred that the examples can obtain a stable friction coefficient regardless of the braking conditions.

[0083] (Rust Evaluation) As in Examples 1 to 3, a cured film of titanium oxide coating solutions-1 to 3 was formed to a thickness of approximately 25 μm on a cast iron (FC250) rotor (φ64 mm). Each rotor was placed with the cured film facing up in a plastic case with an air hole drilled at the top, via a 2 cm high spacer. Next, water was poured into the plastic case to a height of 1 cm, and the plastic case containing the water was left at room temperature, conditioned to 23°C. The state of rust formation on the rotor surface is shown in Table 3.

[0084]

[0085] The results in Table 3 show that the rotor coated with the titanium oxide coating liquid was inhibited from rusting.

[0086] The disclosure of PCT / JP2023 / 034788 is incorporated herein by reference in its entirety. All publications, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual publication, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A resin composition for use in coating a brake rotor sliding surface, comprising at least one compound selected from the group consisting of titanium compounds, magnesium compounds, and lithium compounds, and an epoxy resin or a precursor thereof, wherein the epoxy equivalent of the epoxy resin or precursor thereof is 900 g / eq or less.

2. The resin composition according to claim 1, wherein the compound is a titanium compound.

3. The resin composition according to claim 1, wherein the titanium compound is at least one selected from the group consisting of titanium oxide and titanium black.

4. The resin composition according to claim 1, wherein the content of said compound is 25% by mass to 90% by mass based on the total solid content.

5. The resin composition according to claim 1, wherein the epoxy equivalent of the epoxy resin or its precursor is 600 g / eq or less.

6. The resin composition according to claim 1, wherein the epoxy resin or its precursor comprises a bisphenol type epoxy resin or its precursor.

7. A rotor for a brake, the rotor having a sliding surface comprising a metal-containing layer formed from the resin composition according to any one of claims 1 to 6.

8. A set for producing a brake rotor, comprising: at least one compound selected from the group consisting of titanium compounds, magnesium compounds, and lithium compounds; an epoxy resin or a precursor thereof; and a rotor member.

9. A method for manufacturing a rotor for a brake using the set for manufacturing a rotor for a brake according to claim 8, comprising forming a metal-containing layer by applying a resin composition containing the compound and the epoxy resin or a precursor thereof to the sliding surface of the rotor member.

10. A brake comprising the brake rotor according to claim 7 and a brake pad.

11. The brake of claim 10, wherein the metal-containing layer has a thickness of 1 μm to 100 μm.

12. The brake according to claim 10, wherein the brake rotor is made of cast iron and has been subjected to at least one of surface treatments including grinding, polishing, and machining.

13. The brake according to claim 10, wherein the brake pad is a non-asbestos organic pad.

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