Detergent composition and method for manufacturing vehicle wheels

Abstract

To provide a cleaning agent composition that is classified as a non-hazardous material under the Fire Service Act, has excellent cleaning properties for pad-derived components and adhesives of adhesive tapes adhering to the printed surface after pad printing, and is less likely to dissolve the ink layer formed by pad printing and the non-printed areas of the printed material, and a method for manufacturing vehicle wheels. [Solution] A cleaning agent composition for use on vehicle wheels, comprising 19 to 60% by mass of component (A), 5 to 13% by mass of component (B), 20% by mass or more of component (D), and substantially free of component (C), or a cleaning agent composition comprising 0.1 to 60% by mass of component (A), 0.1 to 60% by mass of component (B), 1 to 75% by mass of component (C), and 20% by mass or more of component (D). (A) Ingredient: Glycol ether (B) Ingredients: Sodium hydroxide (C) Ingredients: Surfactants (D) Component: Water

Description

[Technical Field]

[0001] The present invention relates to a cleaning agent composition and a method for manufacturing vehicle wheels. [Background technology]

[0002] Pad printing is a decorative printing method in which ink is applied to a printing pad (hereinafter also simply referred to as "pad"), and the ink-covered pad is pressed against the surface to be printed, thereby transferring the ink to the surface. For example, vehicle wheels may be decorated by pad printing using colored ink on the wheel base, and then further pad printing using colorless ink or colored clear ink as needed. In addition, before or after pad printing, the pad may be pressed against adhesive tape to remove any ink remaining on the pad, as well as any dust such as lint or hair adhering to the pad surface.

[0003] The ink layer, consisting of colored ink transferred to the wheel substrate, is prone to reduced adhesion to the wheel substrate, decreased chipping resistance, water resistance, and changes in color tone. When pad printing is further performed using colorless ink or colored clear ink, a step may occur between the pad-printed area (printed area) and the non-pad-printed area (non-printed area), resulting in an inexpensive appearance similar to that of a sticker. Therefore, typically, after pad printing, a topcoat is applied to the printed surface. However, when the pad is pressed against the surface to be printed, silicone oil contained in the pad, dirt on the pad (hereinafter collectively referred to as "pad-derived components"), and adhesive from adhesive tape attached to the pad may adhere to the printed surface. If a topcoat is applied to the printed surface in this state, the topcoat paint will be repelled, making it difficult to form a uniform topcoat film.

[0004] As a method to prevent the topcoat paint from repelling after pad printing, for example, Patent Document 1 discloses a method of wiping off oil adhering to the surface of the pad before pad printing. Patent Document 2 discloses a method for removing wax adhering to a printed surface after pad printing using carbon tetrachloride, soap, detergent, kerosene, toluene, xylene, methyl ethyl ketone, etc. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-94528 [Patent Document 2] Japanese Patent Application Publication No. 57-193312 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, as described in Patent Document 1, wiping off the oil adhering to the surface of the pad reduces the amount of silicone oil contained in the pad, which lowers its oil bleeding properties. This reduces the flexibility of the pad, decreasing its ability to conform to the shape of the printed material, and also reduces the ink repulsion of the silicone rubber layer that makes up the pad, leading to problems such as a decrease in print quality and a reduction in the number of times the pad can be used.

[0007] In the case of the method described in Patent Document 2, kerosene (kerosene), toluene, xylene, and methyl ethyl ketone used for wax removal fall under Class 4 Dangerous Goods (flammable liquids) under the Fire Service Act, and carbon tetrachloride falls under substances whose dangers are feared under the Chemical Substances Control Promotion Law (PRTR Law), so handling is restricted legally. Even when considering a cleaning facility using dangerous goods with a designated quantity less than 30 times, various countermeasures are required, and there are significant restrictions on equipment costs and workplaces. Since fatty acid salts, which are the main components of soaps and detergents, have poor solubility in silicone oil and adhesives of adhesive tapes mainly composed of acrylic resins, etc., it is difficult to sufficiently clean the silicone oil and adhesive of the adhesive tape that adhere during pad printing. Also, benzene and toluene have high dissolving power and excellent detergency for silicone oil and adhesives of adhesive tapes, but the ink (hereinafter also referred to as the "ink layer") itself transferred to the printed surface by pad printing also dissolves.

[0008] If a surface conditioner, anti-repellent, defoaming agent, etc. are added to the topcoat paint, generation of repellency can be suppressed, but discoloration of the topcoat film, reduction of interlayer adhesion with the undercoat film, reduction of adhesion during recoating, etc. may occur. Also, due to the difference in the electro-negativity between the topcoat paint added with an anti-repellent or defoaming agent, etc. and the undercoat film, there are cases where the topcoat film is repelled and smooth painting becomes difficult.

[0009] Therefore, there is a need for a cleaning agent that falls under non-dangerous goods under the Fire Service Act, has excellent detergency for pad-derived components such as silicone oil adhering to the printed surface after pad printing and adhesives of adhesive tapes, and is difficult to dissolve the ink layer formed by pad printing. Especially in vehicle wheels, dimensional accuracy on the order of ±100 minutes in millimeters, that is, 0.01 mm, may be required in the hub hole, so the cleaning agent is also required to be difficult to dissolve in the non-printed area (non-printing area) of the printed object (the object of pad printing) such as the wheel base.

[0010] Therefore, the present invention aims to provide a cleaning agent composition that falls under non-dangerous substances under the Fire Service Act, has excellent detergency against pad-derived components adhering to the printed surface after pad printing and adhesives of adhesive tapes, and is also difficult to dissolve the ink layer formed by pad printing and the non-printing areas of printed materials, as well as a method for manufacturing vehicle wheels.

Means for Solving the Problems

[0011] The present invention has the following aspects. [1] A cleaning agent composition for use in vehicle wheels, comprising: Component (A): glycol ether, and Component (B): sodium hydroxide, and Component (D): water, and containing, with respect to the total mass of the cleaning agent composition, the content of component (A) being 19 to 60% by mass, the content of component (B) being 5 to 13% by mass, and the content of component (D) being 20% by mass or more, A cleaning agent composition substantially free of surfactants. [2] A cleaning agent composition for use in vehicle wheels, comprising: Component (A): glycol ether, and Component (B): sodium hydroxide, and Component (C): surfactant, and Component (D): water, and containing, with respect to the total mass of the cleaning agent composition, the content of component (A) being 0.1 to 60% by mass, the content of component (B) being 0.1 to 60% by mass, the content of component (C) being 1 to 75% by mass, and the content of component (D) being 20% by mass or more, a cleaning agent composition. [3] The cleaning agent composition according to [1] or [2], wherein component (A) includes dipropylene glycol monomethyl ether. [4] A method for manufacturing vehicle wheels, comprising a step of pad printing a wheel substrate, a step of cleaning the wheel substrate after pad printing using the cleaning agent composition according to any one of [1] to [3], and a step of painting the cleaned wheel substrate. [5] The method for manufacturing a vehicle wheel according to [4], wherein the cleaning agent composition is heated to 40-60°C to clean the wheel substrate after pad printing. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a cleaning agent composition that is classified as a non-hazardous material under the Fire Service Act, has excellent cleaning properties for pad-derived components and adhesives of adhesive tapes adhering to the printed surface after pad printing, and is less likely to dissolve the ink layer formed by pad printing and the non-printed areas of the printed material, as well as a method for manufacturing vehicle wheels. [Brief explanation of the drawing]

[0013] [Figure 1] This is a flowchart illustrating an example of the process for manufacturing a vehicle wheel according to the present invention. [Figure 2] This flowchart illustrates another example of the process for manufacturing a vehicle wheel according to the present invention. [Figure 3] This flowchart illustrates another example of the process for manufacturing a vehicle wheel according to the present invention. [Figure 4] (a) to (e) are schematic cross-sectional views showing an example of a wheel base. [Figure 5] (f) and (g) are schematic cross-sectional views showing an example of a wheel base. [Figure 6] (K5) This is a flowchart illustrating an example of the process flow. [Figure 7] (K8) This is a flowchart illustrating an example of the process flow. [Modes for carrying out the invention]

[0014] The embodiments of the present invention will be described in detail below. The following embodiments are merely illustrative for illustrating the present invention and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from its spirit. In this specification and in the claims, a numerical range represented by "~" means a numerical range that includes the numbers before and after "~" as the lower and upper limits, respectively. For example, A~B is synonymous with A or greater and B or less. The numerical ranges of content, various physical properties, and characteristic values ​​disclosed herein can be modified by arbitrarily combining their lower and upper limits to create new numerical ranges.

[0015] Furthermore, in the present invention and this specification, the following terms have the following meanings. "Substrate" refers to the object to be printed on before pad printing. Specifically, it refers to the wheel base before pad printing. "Printed material" refers to the object to be printed on after pad printing has been applied. Specifically, it refers to the wheel base after pad printing. "Printed surface" refers to the side of the material to be pad printed. "Printed surface" refers to the pad-printed surface of a printed material, that is, the surface on which the following ink layer is formed. The "ink layer" refers to the ink transferred to the printed surface by pad printing. The "printed area" refers to the pad-printed area of ​​the printed surface, that is, the area where the ink layer is formed. "Non-printed area" refers to the area of ​​the printed surface other than the printed area, that is, the area where the ink layer is not formed.

[0016] [Detergent composition] The cleaning agent composition (S) of the present invention is a cleaning agent composition used for vehicle wheels and contains the following components (A), (B), and (D). The detergent composition (S) of the present invention may contain the component (C) shown below, or may substantially not contain component (C). The detergent composition (S) of the present invention may or may not contain components other than the components (A), (B), (C), and (D) shown below (hereinafter also referred to as "optional components"). (A) Ingredient: Glycol ether (B) Ingredients: Sodium hydroxide (C) Ingredients: Surfactants (D) Component: Water

[0017] Hereinafter, a detergent composition (S) that substantially does not contain component (C) (hereinafter also referred to as "detergent composition (S1)") will be described as the first embodiment, and a detergent composition (S) that contains component (C) (hereinafter also referred to as "detergent composition (S2)") will be described as the second embodiment, and an example of each form will be explained.

[0018] "First Embodiment" The detergent composition (S1) of this embodiment is a liquid composition containing component (A), component (B), and component (D), and substantially free of component (C). The detergent composition (S1) may further contain optional components in addition to components (A), (B), and (D) as needed. In this invention, "substantially absent" means not actively incorporating any substance, except for those unintentionally present.

[0019] <(A) component> (A) Component is glycol ether. As mentioned above, components originating from the pad, such as silicone oil contained in the pad or dirt on the pad, may adhere to the printed surface after pad printing. Also, when removing ink remaining on the pad or dust adhering to the pad surface by pressing the pad against adhesive tape before or after pad printing, adhesive from the adhesive tape may adhere to the pad. If pad printing is performed with adhesive attached to the pad, the adhesive attached to the pad may transfer to the printed surface and adhere to it. The cleaning agent composition (S1) contains component (A), which reduces the surface tension between the printed surface and the pad-derived components (especially silicone oil) and adhesive from the adhesive tape that adhere to the printed surface after pad printing, thereby increasing penetration and making it possible to remove the pad-derived components and adhesive from the adhesive tape from the printed surface. In the following specification, the pad-derived components adhering to the printed surface after pad printing, and the adhesive of the adhesive tape adhering to the printed surface after pad printing, are collectively referred to as "adhered components adhering to the printed surface."

[0020] Examples of glycol ethers include alkylene glycol monoalkyl ethers and alkylene glycol dialkyl ethers. Examples of alkylene glycol monoalkyl ethers include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monopropyl ether, triethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, and triethylene glycol Examples include ethylene glycol monoalkyl ethers such as propylene glycol monophenyl ether; propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, propylene glycol monohexyl ether, dipropylene glycol monohexyl ether, propylene glycol monophenyl ether, and other propylene glycol monoalkyl ethers. Examples of alkylene glycol dialkyl ethers include ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, and triethylene glycol dibutyl ether; and propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol diethyl ether, tripropylene glycol diethyl ether, propylene glycol dipropyl ether, dipropylene glycol dipropyl ether, tripropylene glycol dipropyl ether, propylene glycol dibutyl ether, dipropylene glycol dibutyl ether, and tripropylene glycol dibutyl ether. Among these, alkylene glycol monoalkyl ethers are preferred as glycol ethers, propylene glycol monoalkyl ethers are more preferred, and dipropylene glycol monomethyl ethers are even more preferred, from the viewpoint of having particularly excellent cleaning properties for adhering components to the printed surface. Glycol ethers may be used individually or in combination of two or more types.

[0021] The content of component (A) is 19 to 60% by mass of the total mass of the cleaning agent composition (S1). If the content of component (A) is above the lower limit, the cleaning performance against pad-derived components (especially silicone oil) and adhesives (acrylic adhesives) of adhesive tapes that adhere to the printed surface after pad printing will be improved. Cleaning performance tends to improve as the content of component (A) increases, but component (A) itself is classified as a Class 4 flammable liquid under the Fire Service Act. Therefore, if the content of component (A) becomes too high, the cleaning agent composition (S1) will be classified as a hazardous material under the Fire Service Act. By keeping the content of component (A) below the upper limit, the cleaning agent composition (S1) can be treated as a non-hazardous material under the Fire Service Act. In addition, the ink layer formed by pad printing will be less likely to dissolve.

[0022] <(B) component> (B) Component is sodium hydroxide. Sodium hydroxide is a builder. The presence of component (B) in the cleaning agent composition (S1) enhances the effect of component (A), thereby strengthening its cleaning ability against adhering components on the printed surface. Therefore, even if the content of component (A) is 60% by mass or less, good cleaning performance can be maintained.

[0023] The content of component (B) is 5 to 13% by mass relative to the total mass of the cleaning agent composition (S1). If the content of component (B) is above the lower limit, the effect of component (A) can be sufficiently enhanced, and good cleaning performance against adhering components on the printed surface can be maintained. On the other hand, if the content of component (B) is too high, the etching action and ink-dissolving action of component (B) may dissolve non-printed areas, ink, or coatings depending on the material of the printed material, which may affect the required dimensional accuracy, appearance, weather resistance, water resistance, adhesion, and other coating performance. When the printed material is an aluminum wheel base, it is easily etched, and in particular, the fastening parts with the vehicle body (hub holes, bolt hole seating surfaces) are susceptible to etching. If the content of component (B) is below the upper limit, the non-printed areas of the printed material are less likely to dissolve, and the impact on the required dimensional accuracy is minimal. In addition, good performance of the printed material, weather resistance, water resistance, adhesion, and other coating performance can be maintained.

[0024] Here, "having little influence on the required dimensional accuracy" means that the dimensional change of the printed matter is small before and after cleaning the printed matter using the cleaning agent composition (S1). As described above, in the case of a vehicle wheel, dimensional accuracy on the order of ±100 minutes in millimeters, that is, on the order of 0.01 mm, may be required for the hub hole. Whether or not the required dimensional accuracy on the order of ±100 minutes in millimeters is satisfied can be determined, for example, by measuring the surface area of a test piece of AC4CH (aluminum alloy) and calculating the change in weight (weight difference) of the test piece before and after cleaning using the cleaning agent composition (S1), and 3 ) calculating the dimensional change amount from the density of AC4CH (about 2.7 g / cm 2 The weight change amount when the thickness per square meter decreases by 0.01 mm is obtained from the following formula (i). Weight change amount [g / m 2 = (2.7 [g / cm 3 × 1 [m 2 ) × dimensional change amount [mm] = (2.7 [g / cm 3 × 1 [m 2 ) × 0.01 [mm] = 27 [g / m 2 ···(i)

[0025] From the above formula (i), for example, if the weight change amount per square meter is less than 27 g / m 2 , it can be determined that the dimensional accuracy on the order of ±100 minutes (0.01 mm) in millimeters is satisfied. 2 If the location where the required dimensional accuracy is required is the diameter of the inner diameter part of the hub hole, since it is the distance between both ends of the inner diameter part of the hub hole, in order to satisfy the dimensional accuracy on the order of ±100 minutes (0.01 mm) in millimeters, it is required that the changing thickness per side is less than 0.005 mm. In such a case, if the weight change amount per square meter is less than 13.5 g / m 2 , it can be determined that the dimensional accuracy on the order of ±100 minutes (0.01 mm) in millimeters is satisfied. 2If the value is less than this, it can be determined that the dimensional accuracy is on the order of ±100ths of a millimeter (0.01 mm).

[0026] The total content of component (A) and component (B) (hereinafter also referred to as "(A+B) amount") is preferably 80% by mass or less, and more preferably 32-73% by mass, relative to the total mass of the cleaning agent composition (S1). If the (A+B) amount is above the lower limit, good cleaning performance against adhering components on the printed surface can be maintained. If the (A+B) amount is below the upper limit, the cleaning agent composition (S1) can be treated as a non-hazardous material under the Fire Service Act.

[0027] The mass ratio expressed as component (A) / component (B) (hereinafter also referred to as the "(A / B) ratio") is preferably 1.46 to 12, and more preferably 1.46 to 6.

[0028] <(D) component> (D) Component is water. The inclusion of component (D) in the cleaning agent composition (S1) emulsifies adhering components, particularly silicone oil, on the printed surface, making them easier to remove. Furthermore, each component becomes more uniformly dispersed within the cleaning agent composition (S1). Additionally, the cleaning agent composition (S1) can be made non-flammable. Examples of water include pure water, purified water, deionized water, distilled water, and tap water. Water may be used alone or in combination of two or more types.

[0029] The content of component (D) is 20% by mass or more, preferably 20 to 76% by mass, and more preferably 25 to 70% by mass, based on the total mass of the detergent composition (S1). If the content of component (D) is above the lower limit, the detergent composition (S1) can be treated as a non-hazardous material under the Fire Service Act.

[0030] The total amount of components (A), (B), and (D) (hereinafter also referred to as "(A+B+D) amount") is preferably 44% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and may be 100% by mass, based on the total mass of the detergent composition (S1).

[0031] <Optional ingredients> Optional components are not particularly limited as long as they are components used in cleaning agents, but examples include antioxidants, defoamers, builders other than component (B) (hereinafter also referred to as "other builders"), solvents other than components (A) and (D) (hereinafter also referred to as "other solvents"), rust inhibitors, chelating agents, etc. The optional components may be used individually or in combination of two or more types.

[0032] Examples of antioxidants include phenolic antioxidants such as 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-ethylphenol, and 2,6-di-t-butyl-4-hydroxymethylphenol; amine antioxidants such as diphenyl-p-phenylene-diamine, 4-aminodiphenylamine, and p,p'-dioctyldiphenylamine; phosphorus antioxidants such as tris(2,4-di-t-butylphenyl) phosphite, poly(dipropylene glycol)phenyl phosphite, diphenylisodecyl phosphite, 2-ethylhexyldiphenyl phosphite, and triphenyl phosphite; and sulfur-based antioxidants such as dilaurylthiodipropionate, dimyristylthiodipropionate, and distearylthiodipropionate. Examples of antifoaming agents include ethanol, isopropyl alcohol, monoethanolamide, diethanolamide, kerosene, and glycerin fatty acid esters. Other builders include silicates such as sodium metasilicate and sodium orthosilicate; phosphates such as sodium pyrophosphate, sodium pyrophosphate, and sodium tripolyphosphate; carbonates such as sodium carbonate, sodium bicarbonate, and sodium sesquicarbonate; and potassium hydroxide. Other solvents include alcohols such as methanol, ethanol, propanol, and butanol; and glycols such as ethylene glycol, propylene glycol, and butylene glycol. Examples of rust inhibitors include triphenylphosphine oxide and dimethyldithiocarbamic acid. Examples of chelating agents include gluconates, ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, sodium citrate, tripotassium citrate, potassium dihydrogen citrate, nitrilotriacetic acid, and phosphonates. Antioxidants, defoamers, other builders, other solvents, rust inhibitors, and chelating agents may each be used individually or in combination of two or more types.

[0033] The content of optional components is not particularly limited, as long as it does not impair the effects of the present invention.

[0034] The cleaning agent composition (S1) preferably does not substantially contain special flammable substances, Class 1 petroleum, Class 2 petroleum, Class 3 petroleum, Class 4 petroleum, alcohols, or animal and vegetable oils as defined in Class 4 flammable liquids under the Fire Service Act (excluding component (A)). Examples of flammable liquids of Class 4 other than component (A) include kerosene, toluene, xylene, and methyl ethyl ketone.

[0035] <Manufacturing method> The method for producing the detergent composition (S1) is not particularly limited, and the detergent composition (S1) can be produced in accordance with conventional methods. For example, the detergent composition (S1) can be obtained by mixing component (A), component (B), component (D), and any optional component as needed.

[0036] <Effects and Effects> The cleaning agent composition (S1) described above contains specific amounts of components (A), (B), and (D), and is therefore classified as a non-hazardous material under the Fire Service Act. Furthermore, it exhibits excellent cleaning properties against components derived from the pad and adhesives from adhesive tapes that adhere to the printed surface after pad printing, and is less likely to dissolve the ink layer formed by pad printing and the non-printed areas of the printed material. Since the cleaning agent composition (S1) is classified as a non-hazardous material under the Fire Service Act, it is easy to handle and is less subject to legal restrictions or restrictions on the work location. Since the cleaning agent composition (S1) has excellent cleaning properties against adhering components on the printed surface, even if the printed surface is painted with a topcoat after cleaning with the cleaning agent composition (S1), the topcoat paint is less likely to be repelled, and a uniform topcoat film can be easily formed. Since the cleaning agent composition (S1) does not easily dissolve the ink layer formed by pad printing, the decoration applied to the printed material can be well maintained. Since the cleaning agent composition (S1) does not easily dissolve the non-printed areas of the printed material, it has little impact on the required dimensional accuracy, and for example, it can easily meet dimensional accuracy on the order of ±100ths of a millimeter (0.01 mm).

[0037] "Second Embodiment" The detergent composition (S2) of this embodiment is a liquid composition containing component (A), component (B), component (C), and component (D). The detergent composition (S1) may further contain optional components in addition to components (A), (B), (C), and (D) as needed.

[0038] <(A) component> Since component (A) is the same as component (A) contained in the detergent composition (S1) of the first embodiment, its description is omitted. The content of component (A) is 0.1 to 60% by mass of the total mass of the cleaning agent composition (S2), preferably 0.5 to 50% by mass, more preferably 1 to 30% by mass, and even more preferably 2.5 to 25% by mass. If the content of component (A) is above the lower limit, the cleaning performance against pad-derived components (especially silicone oil) and adhesives (acrylic adhesives) of adhesive tapes adhering to the printed surface after pad printing is improved. If the content of component (A) is below the upper limit, the cleaning agent composition (S2) can be treated as a non-hazardous material under the Fire Service Act. In addition, the ink layer formed by pad printing becomes less likely to dissolve.

[0039] <(B) component> Since component (B) is the same as component (B) contained in the detergent composition (S1) of the first embodiment, its description is omitted. The content of component (B) is 0.1 to 60% by mass of the total mass of the cleaning agent composition (S2), preferably 0.5 to 30% by mass, more preferably 1 to 10% by mass, and even more preferably 2.5 to 5% by mass. If the content of component (B) is above the lower limit, the effect of component (A) can be sufficiently enhanced, and good cleaning performance against adhering components on the printed surface can be maintained. If the content of component (B) is below the upper limit, the non-printed areas of the printed material are less likely to dissolve, and the impact on the required dimensional accuracy is minimal. In addition, good coating performance such as the appearance of the printed material, weather resistance, water resistance, and adhesion can be maintained.

[0040] The total content of component (A) and component (B) (hereinafter also referred to as "(A+B) amount") is preferably 1 to 75% by mass, more preferably 3 to 65% by mass, even more preferably 5 to 50% by mass, and particularly preferably 5 to 30% by mass, based on the total mass of the cleaning agent composition (S2). If the (A+B) amount is above the lower limit, good cleaning performance against adhering components on the printed surface can be maintained. If the (A+B) amount is below the upper limit, the cleaning agent composition (S1) can be treated as a non-hazardous material under the Fire Service Act.

[0041] The mass ratio of component (A) to component (B) (hereinafter also referred to as the "(A / B) ratio") is preferably 0.01 to 300, more preferably 0.1 to 100, even more preferably 0.5 to 65, particularly preferably 0.7 to 30, and most preferably 1 to 5. If the (A / B) ratio is within the above range, the cleanability against adhering components to the printed surface will be further improved. In particular, if the content of component (A) and component (B) is 2.5% by mass or more each, and the (A / B) ratio is within the above range, the cleanability against adhering components to the printed surface will be further improved.

[0042] <(C) component> Component (C) is a surfactant. The presence of component (C) in the cleaning agent composition (S2) makes it easier for adhering components, particularly silicone oil, to be solubilized and emulsified with component (D) on the printed surface, thus making them easier to remove from the printed surface. Furthermore, the etching and ink-dissolving effects of component (B) and component (A) can be reduced.

[0043] Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, anionic surfactants and nonionic surfactants are preferred, and nonionic surfactants are more preferred. Surfactants may be used individually or in combination of two or more types.

[0044] Examples of anionic surfactants include those having a carboxylic acid, sulfonic acid, sulfuric acid, or phosphate structure. Examples of anionic surfactants having a carboxylic acid structure (carboxylic acid-type anionic surfactants) include sodium oleate, sodium laurate, potassium laurate, sodium stearate, lithium stearate, magnesium stearate, calcium stearate, barium stearate, zinc stearate, sodium octanoate, sodium octolate, sodium decanoate, sodium myristic acid, and sodium palmitate. Examples of anionic surfactants having a sulfonic acid structure (sulfonic acid type anionic surfactants) include linear or branched alkylbenzenesulfonates (specifically, sodium toluenesulfonate, sodium cumenesulfonate, sodium octylbenzenesulfonate, sodium decylbenzenesulfonate, sodium dodecylbenzenesulfonate, etc.), sodium naphthalenesulfonate, sodium dibutylsulfonate, etc. Examples of anionic surfactants having a sulfate structure (sulfate ester type anionic surfactants) include sodium lauryl sulfate, potassium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium cetyl sulfate, sodium cocoglyceryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, and triethanolamine laureth sulfate. Examples of anionic surfactants having a phosphate structure (phosphate ester type anionic surfactants) include lauryl phosphate, sodium lauryl phosphate, potassium lauryl phosphate, sodium polyoxyethylene cetyl ether phosphate, sodium polyoxyethylene oleyl ether phosphate, and sodium polyoxyethylene lauryl phosphate. Anionic surfactants may be used individually or in combination of two or more types.

[0045] Examples of nonionic surfactants include polyoxyalkylene-type nonionic surfactants, sorbitan fatty acid esters, fatty acid alkanolamines, polyhydric alcohol fatty acid esters, alkylene oxide adducts of hydrogenated castor oil, sugar fatty acid esters, and alkyl glycosides. Among these, polyoxyalkylene-type nonionic surfactants and sorbitan fatty acid esters are preferred as nonionic surfactants. Nonionic surfactants may be used individually or in combination of two or more types.

[0046] Examples of polyoxyalkylene-type nonionic surfactants include polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene isocetyl ether, polyoxyethylene isostearyl ether, polyoxyethylene octyldodecyl ether, polyoxyethylene behenyl ether, polyoxyethylene decyltetradecyl ether, and polyoxyethylene cetyl ether. Among these, polyoxyethylene isocetyl ether and polyoxyethylene decyltetradecyl ether are preferred. Polyoxyalkylene-type nonionic surfactants may be used individually or in combination of two or more types.

[0047] Examples of sorbitan fatty acid esters include sorbitan laurate, sorbitan isostearate, sorbitan palmitate, sorbitan oleate, and sorbitan caprate. Among these, sorbitan oleate is preferred. Sorbitan fatty acid esters may be used individually or in combination of two or more types.

[0048] Examples of cationic surfactants include quaternary ammonium salts, primary amine salts, secondary amine salts, tertiary amine salts, quaternary amine salts, pyridine derivatives, alkylammonium salts, and dialkylimidazolinium salts. Examples of amphoteric surfactants include betaine-type surfactants, imidazoline-type surfactants, alkylamine oxides, and alkylamino fatty acid salts.

[0049] The content of component (C) is 1 to 75% by mass, preferably 15 to 75% by mass, and more preferably 50 to 75% by mass, based on the total mass of the cleaning agent composition (S2). If the content of component (C) is above the lower limit, the adhering components, especially silicone oil, attached to the printed surface will be sufficiently solubilized and sufficiently emulsified with component (D). If the content of component (C) is above the upper limit, the adhering components attached to the printed surface can be removed.

[0050] The total amount of components (A), (B), and (C) (hereinafter also referred to as "(A+B+C) amount") is preferably 80% by mass or less, more preferably 31-80% by mass, and more preferably 50-80% by mass, based on the total mass of the cleaning agent composition (S2). If the (A+B+C) amount is above the lower limit, good cleaning performance against adhering components on the printed surface can be maintained. If the (A+B+C) amount is below the upper limit, the cleaning agent composition (S2) can be treated as a non-hazardous material under the Fire Service Act.

[0051] <(D) component> Since component (D) is the same as component (D) contained in the detergent composition (S1) of the first embodiment, its description is omitted. The content of component (D) is 20% by mass or more, preferably 20 to 75% by mass, and more preferably 20 to 50% by mass, based on the total mass of the detergent composition (S2). If the content of component (D) is above the lower limit, the detergent composition (S2) can be treated as a non-hazardous material under the Fire Service Act.

[0052] The total amount of components (A), (B), (C), and (D) (hereinafter also referred to as "(A+B+C+D) amount") is preferably 25% by mass or more, more preferably 51% by mass or more, even more preferably 80% by mass or more, and may be 100% by mass, based on the total mass of the detergent composition (S2).

[0053] <Optional ingredients> Examples of optional components include those exemplified in the description of the first embodiment. The optional components may be used individually or in combination of two or more types. The content of optional components is not particularly limited, as long as it does not impair the effects of the present invention.

[0054] The cleaning agent composition (S2) preferably does not substantially contain special flammable substances, Class 1 petroleum, Class 2 petroleum, Class 3 petroleum, Class 4 petroleum, alcohols, or animal and vegetable oils as defined in Class 4 flammable liquids under the Fire Service Act (excluding component (A)). Other examples of Class 4 flammable liquids besides component (A) include those exemplified in the description of the first embodiment.

[0055] <Manufacturing method> The method for producing the detergent composition (S2) is not particularly limited, and the detergent composition (S2) can be produced in accordance with conventional methods. For example, the detergent composition (S2) can be obtained by mixing component (A), component (B), component (C), component (D), and any optional component as needed.

[0056] <Effects and Effects> The cleaning agent composition (S2) described above contains specific amounts of components (A), (B), (C), and (D), and is therefore classified as a non-hazardous material under the Fire Service Act. Furthermore, it exhibits excellent cleaning properties against components derived from the pad and adhesives from adhesive tapes that adhere to the printed surface after pad printing, and is less likely to dissolve the ink layer formed by pad printing and the non-printed areas of the printed material. Since the cleaning agent composition (S2) is classified as a non-hazardous material under the Fire Service Act, it is easy to handle and is less subject to legal restrictions or restrictions on the work location. Since the cleaning agent composition (S2) has excellent cleaning properties against adhering components on the printed surface, even if the printed surface is painted with a topcoat after cleaning with the cleaning agent composition (S2), the topcoat paint is less likely to be repelled, and a uniform topcoat film can be easily formed. Since the cleaning agent composition (S2) does not easily dissolve the ink layer formed by pad printing, the decoration applied to the printed material can be well maintained. Since the cleaning agent composition (S2) does not easily dissolve the non-printed areas of the printed material, it has little impact on the required dimensional accuracy, and for example, it can easily meet dimensional accuracy on the order of ±100ths of a millimeter (0.01 mm).

[0057] "Usage" The cleaning agent composition of the present invention is suitable as a cleaning agent for printed materials after pad printing. In particular, it is suitable as a cleaning agent used in the cleaning process after pad printing when manufacturing vehicle wheels decorated by pad printing. The following describes an example of a method for manufacturing vehicle wheels using the cleaning agent composition of the present invention.

[0058] [Manufacturing method for vehicle wheels] The method for manufacturing a vehicle wheel according to this embodiment includes the following steps: (K7), (K8), and (K9). The method for manufacturing a vehicle wheel may further include, as necessary, steps (K1), (K2), and (K3) shown below, prior to step (K7). The method for manufacturing a vehicle wheel may, after step (K9), further include, if necessary, step (K10) as shown below. Furthermore, the method for manufacturing a vehicle wheel may further include, as necessary, steps (K4), (K5), and (K6) shown below, before step (K7). If the method for manufacturing a vehicle wheel further includes steps (K1), (K2), and (K3), it is preferable that steps (K4), (K5), and (K6) are included between steps (K3) and (K7). (K1) Process: Process for forming the wheel base (K2) Process: A process for pre-treating the molded wheel base. (K3) Process: A process of painting the wheel base after pretreatment (after (K2) process). (K4) Process: Machining process for the wheel base (K5) Process: A process for pre-treating the wheel base after machining. (K6) Process: A process of painting the wheel base after pretreatment (after (K5) process). (K7) Process: Pad printing of the wheel base. (K8) Process: A process for cleaning the wheel substrate after pad printing. (K9) Process: A process of painting the wheel base after cleaning (after (K8) process). (K10) Process: A process for post-treatment of the wheel base after painting (after (K9) process).

[0059] Specific examples of methods for manufacturing vehicle wheels include an embodiment including steps (K7) to (K9) as shown in Figure 1; an embodiment including steps (K1) to (K3) and steps (K7) to (K10) as shown in Figure 2; and an embodiment including steps (K1) to (K10) as shown in Figure 3. The following describes each step.

[0060] <(K1) process> (K1) is the process of forming the wheel base (hereinafter also referred to as the "forming process"). The wheel base is formed by processing a wheel base material, such as aluminum, aluminum alloy, magnesium, steel, titanium, or titanium alloy, to the desired shape. In particular, it is preferable to process and form a wheel base material, mainly aluminum or aluminum alloy, to the desired shape. Examples of methods for processing the wheel base material include casting and forging.

[0061] <(K2) process> Step (K2) is a process for pre-treating the molded wheel base (hereinafter also referred to as the "first pre-treatment step"). In step (K2), substances (e.g., dust, oil, oxide film, etc.) that adhere to the surface of the wheel base material in step (K1) and hinder the adhesion between the wheel base material and the coating are removed. In addition, a chemical conversion coating is formed to improve the adhesion between the wheel base material and the coating. If the wheel base material is aluminum or an aluminum alloy, and the chemical conversion coating is a Zr-based coating, then Zr is added at a concentration of 10-50 mg / m². 2 For Ti-based coatings, the Ti content should be 50-150 mg / m². 2It is preferable that it contains this information. The pretreatment process (K2) is also referred to as the "first pretreatment."

[0062] Process (K2) may be carried out in the same way as process (K5) described later, or in a different way. If process (K2) is carried out in a different way than process (K5), and the wheel base is made of aluminum or an aluminum alloy, for example, in process (K5), in the degreasing process to remove dust and oil and the pickling process to remove oxide film, cleaning is performed using a cleaning agent with low or no solubility for aluminum or aluminum alloy in order to prevent loss of luster in areas where the aluminum or aluminum alloy base material is exposed. On the other hand, in process (K2), cleaning may be performed using a cleaning agent with high solubility for aluminum or aluminum alloy in order to prevent loss of luster in areas where the aluminum or aluminum alloy base material is exposed.

[0063] <(K3) process> Step (K3) is the process of painting the wheel base after the first pretreatment (hereinafter also referred to as the "first undercoat painting process"). In step (K3), a primer layer, a first colored base layer, a second colored base layer, a metal reflective film, a color clear layer, a top clear layer, etc., are formed on the chemical conversion film formed in step (K2). Hereinafter, these will be collectively referred to as the "first undercoat film." The wheel substrate preferably has one or more first undercoat films, whether colored or colorless. After painting, the first undercoat is usually cured and dried by methods such as baking.

[0064] (K3) Examples of wheel substrates after the process include: wheel substrate 10A, as shown in Figure 4(a), on a wheel base material 11, with a conversion coating 12, primer layer 13, first colored base layer 14, second colored base layer 15, metal reflective coating 16, color clear layer 17, and top clear layer 18 laminated in this order; wheel substrate 10B, as shown in Figure 4(b), on a wheel base material 11, with a conversion coating 12, primer layer 13, first colored base layer 14, second colored base layer 15, metal reflective coating 16, and top clear layer 18 laminated in this order; wheel substrate 10C, as shown in Figure 4(c), on a wheel base material 11, with a conversion coating 12, primer layer 13, first colored base layer 14, metal reflective coating 16, and top clear layer 18 laminated in this order; Figure 4 Examples include: a wheel substrate 10D in which a chemical conversion coating 12, a primer layer 13, a first colored base layer 14, and a top clear layer 18 are laminated in that order on a wheel substrate 11 as shown in (d); a wheel substrate 10E in which a chemical conversion coating 12, a primer layer 13, and a first colored base layer 14 are laminated in that order on a wheel substrate 11 as shown in Figure 4(e); a wheel substrate 10F in which a chemical conversion coating 12, a color clear layer 17, and a top clear layer 18 are laminated in that order on a wheel substrate 11 as shown in Figure 5(f); and a wheel substrate 10G in which a chemical conversion coating 12 and a top clear layer 18 are laminated in that order on a wheel substrate 11 as shown in Figure 5(g). However, the wheel substrate is not limited to these, and the layer configuration of the first undercoat coating will differ depending on the painting specifications of the wheel.

[0065] The thickness of the primer layer 13 is preferably 10 to 150 μm. The thickness of the first colored base layer 14 is preferably 10 to 35 μm. The thickness of the second colored base layer 15 is preferably 10 to 35 μm. The thickness of the metal reflective film 16 is preferably 0.01 to 1 μm. The thickness of the color clear layer 17 is preferably 10 to 35 μm. The thickness of the top clear layer 18 is preferably 20 to 35 μm. The top clear coat 18 may be a glossy clear coat, a matte clear coat, or a colored clear coat.

[0066] <(K4) process> Process (K4) is the process of cutting the wheel base (hereinafter also referred to as the "cutting process"). In the (K4) process, a portion of the design surface is machined to form a machined surface. The cutting method is not particularly limited and can include turning, machining using a machining center, or manual machining. The cutting area is not particularly limited and may be a flat surface or a curved surface. In addition, a portion of the design surface may be cut along with the first undercoat coating formed in step (K3). There are no particular restrictions on the number of cutting operations or the combination of cutting methods. In the (K4) process, a machined surface is formed where the wheel base material is exposed due to cutting, and a rounded surface is formed where a primer coat has been applied. The machined surface is preferably a bright surface.

[0067] <(K5) process> The (K5) process is a process for pre-treating the wheel base after machining (hereinafter also referred to as the "second pre-treatment process"). The pretreatment process (K5) is also referred to as the "second pretreatment." The (K5) process includes, for example, the (K5-1), (K5-2), (K5-3), (K5-4), and (K5-5) processes, as shown in Figure 5.

[0068] Step (K5-1) is the cleaning step. The (K5-1) process is intended to clean and remove dust, cutting oil, and oxide film that adheres to the wheel base in the (K4) process. In step (K5-1), the wheel base after cutting is cleaned by bringing the treated water to which the chemical solution has been added into contact with the wheel base after cutting. Specifically, the wheel base after cutting is cleaned by immersing it in the treated water (immersion cleaning) or by spraying the treated water onto the wheel base after cutting (shower cleaning). Note that process (K5-1) is also called the "first cleaning process".

[0069] (K5-1) The process may be performed once or two or more times. (K5-1) When performing the process more than once, different chemicals may be used for the first and subsequent runs, or the same chemical may be used. Also, the washing conditions may be changed for the first and subsequent runs, or they may be the same. The treated water may be used at room temperature or heated. If heated, the preferred temperature is 20-70°C.

[0070] Step (K5-2) is the washing step. The (K5-2) process is intended to remove dirt adhering to the wheel base and any remaining residue from the treatment solution used in the (K5-1) process. In step (K5-2), the wheel base after cutting is cleaned by bringing it into contact with cleaning water such as tap water, industrial water, or pure water. Specifically, the wheel base after cutting is cleaned by immersing it in the cleaning water (immersion cleaning) or by spraying the cleaning water onto the wheel base after cutting (shower cleaning). Note that process (K5-2) is also called the "second cleaning process".

[0071] (K5-2) The process may be performed once or two or more times. (K5-2) If the process is performed more than once, the washing conditions may be changed between the first and subsequent washes, or they may be the same. The washing water may be used at room temperature or it may be heated. If heated, the temperature should preferably be between 20 and 70°C.

[0072] The order of steps (K5-1) and (K5-2) may be reversed, but it is preferable to perform step (K5-2) after step (K5-1). Furthermore, at least one of the treated water used in step (K5-1) and the washing water used in step (K5-2) may contain room temperature air or heated air. By including air in the treated water and washing water, a cleaning effect can be obtained by trapping dirt on the surface of the air bubbles and by the trapped air bubbles separating from the washing surface, thereby improving cleaning performance. As a result, the processing time can be shortened, and the occurrence of discoloration of the first undercoat film formed in step (K3) due to the effects of chemicals and dirt contained in the treated water, as well as poor adhesion of the film due to remaining dirt, can be reduced. In addition, by shortening the processing time, the influence of the processing liquid on the first undercoat film can be reduced, and a decrease in adhesion between the film and the wheel base, such as "water resistance in rainy weather," "chemical resistance to cleaning agents used during car washing and de-icing agents used in snowy areas," and "weather resistance due to outdoor use," which are required in the usage environment of vehicle wheels, can be suppressed.

[0073] Step (K5-3) is a chemical treatment process. The (K5-3) process is aimed at improving the adhesion of the coating film formed in the (K6) process (described later) to the machined surface formed in the (K4) process. In step (K5-3), a chemical conversion film is formed on the first undercoat film formed in step (K3). The chemical treatment method is not particularly limited, and known methods can be used.

[0074] Step (K5-4) is the washing step. Step (K5-4) is preferably carried out using the same processing method as step (K5-2). Note that process (K5-4) is also called the "third cleaning process".

[0075] Step (K5-5) is the drying step. Step (K5-5) is a step aimed at evaporating moisture. While there are no particular limitations on the drying method, examples include methods such as baking the wheel base or using air blowing.

[0076] <(K6) process> Step (K6) is the process of painting the wheel base after the second pretreatment (hereinafter also referred to as the "second undercoat painting process"). In step (K6), painting is carried out on the machined surface formed in step (K4) and the first undercoat film formed in step (K3). In step (K6), for example, one to three layers of paint film (hereinafter also referred to as the "second undercoat film") are formed by applying one or more of the following: clear paint, colored clear paint, and matte clear paint. (K6) The process may be performed once or two or more times. That is, the second undercoat may be a single-layer structure consisting of one layer, or it may be a laminated structure consisting of two or more layers. If the second undercoat has a laminated structure, the number of layers is preferably 2 to 6. After painting, the second undercoat is usually cured and dried by methods such as baking.

[0077] <(K7) process> Process (K7) is the process of pad printing the wheel base (hereinafter also referred to as the "pad printing process"). In step (K7), if necessary, before transferring the ink to the wheel base using the pad, the pad may be attached to adhesive tape to remove any remaining ink on the pad and any dust such as lint or hair adhering to the pad surface. Then, the ink representing the desired characters, figures, or symbols is transferred to the surface (printing surface) of the wheel base using the pad, forming an ink layer. After pad printing, the ink layer is usually cured and dried by methods such as baking. The method of applying ink to the pad is not particularly limited, but examples include applying ink directly to the pad, or applying ink to the pad by spraying or inkjet technology. There are no particular restrictions on the thickness of the ink layer.

[0078] The adhesive tape used for cleaning the pad is not particularly limited as long as it can remove ink remaining on the pad and dust such as lint and hair adhering to the pad surface, but it is characterized by having an adhesive layer. Examples of adhesives that make up the adhesive layer include acrylic adhesives and rubber adhesives. Among these, acrylic adhesives are preferred from the viewpoint of being able to more easily exhibit the cleaning effect of the cleaning agent composition (S) used in the (K8) step described later on the adhesive.

[0079] Acrylic adhesives commonly used are sometimes called modified acrylic resins, and are typically used by imparting tackiness to an acrylic acid ester polymer. Acrylic acid esters are compounds represented by the following general formula (1). CH2=C(R 1 )COOR 2 ...(1) (In formula (1), R 1 R is a hydrogen atom or a methyl group, 2 (It is an alkyl group.)

[0080] In formula (1), R 1 This is either a hydrogen atom or a methyl group, with a hydrogen atom being preferred. In formula (1), R 2 is an alkyl group. The alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 10, even more preferably 1 to 6, and particularly preferably 1 to 4 carbon atoms. The alkyl group may be linear or branched.

[0081] Examples of acrylic acid esters include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, hexyl acrylate, octyl acrylate, and dodecyl acrylate, as well as alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, hexyl methacrylate, octyl methacrylate, and dodecyl methacrylate. Among these, alkyl acrylates are preferred from the viewpoint of more easily exhibiting the cleaning effect of the cleaning agent composition (S) on adhesives, and methyl acrylate, ethyl acrylate, and n-butyl acrylate are more preferred.

[0082] Acrylic adhesives can be manufactured, for example, as follows: First, an acrylic acid ester is selected and polymerized in the presence of a polymerization initiator to obtain a polymer. Next, in order to increase the adhesiveness of the polymer, the polymer is mixed with at least one of a softener and a viscosity modifier to obtain an acrylic adhesive. Examples of polymerization initiators include peroxides such as benzoyl peroxide and methyl peroxide; and azo compounds such as azobisisobutyronitrile and azobis(2-methylbutyronitrile). Examples of fabric softeners include phthalate esters such as butyl phthalate and dioctyl phthalate. Examples of viscosity modifiers include acrylic thickeners such as acrylic acid ester copolymers, and cellulose thickeners such as chlorocellulose and hydroxypropylcellulose.

[0083] It is believed that component (A) contained in the cleaning agent composition (S) interacts with a portion of the acrylic adhesive and acts on the ester bonds of the acrylic adhesive, thereby improving the cleaning performance of the adhesive of the adhesive tape attached to the surface of the wheel substrate. Furthermore, the acrylic adhesive is hydrolyzed by the action of component (B) contained in the cleaning agent composition (S), and decomposed into an alcohol and a carboxylic acid. Since alcohol and carboxylic acid are readily soluble in water, it is thought that the cleanability of the adhesive of the adhesive tape attached to the surface of the wheel substrate will be improved. Furthermore, from the viewpoint of making the solubility effect of the cleaning agent composition (S) on the acrylic adhesive more readily apparent, it is preferable that the acrylic adhesive substantially does not contain at least one of the flame retardant and the ultraviolet absorber. Examples of flame retardants include boron-based flame retardants such as boric acid and borate salts, and phosphorus-based flame retardants such as triphenyl phosphate esters. Examples of UV absorbers include benzotriazol and homosalate.

[0084] Commonly used rubber-based adhesives include, for example, rubber components, fillers, and elastomers. Examples of rubber components include styrene-butadiene rubber and ethylene-propylene rubber. Styrene-butadiene rubber is a copolymer of styrene and butadiene. Ethylene-propylene rubber is a copolymer of ethylene and propylene. It is thought that component (A) contained in the cleaning agent composition (S) acts on the rubber chains of the rubber component, causing dissolution. Fillers are added to rubber-based adhesives to improve their strength and durability. Examples of fillers include carbon black and silica. Elastomers are added to rubber-based adhesives to improve their heat resistance and chemical resistance.

[0085] The pads used in pad printing preferably have rubber elasticity, such as silicone rubber, and oil-bleed properties for the purpose of providing ink repulsion and pad flexibility. The type of silicone oil used in the pads is not particularly limited, but examples include methylphenylpolysiloxane and alkyl-modified organopolysiloxane. Both methylphenylpolysiloxane and alkyl-modified organopolysiloxane exhibit hydrophobicity, but when comparing the two, alkyl-modified organopolysiloxane has more hydrophobic properties. Component (A) contained in the detergent composition (S) is hydrophilic, and compounds with hydrophilic properties tend to exhibit better cleaning effects compared to compounds with hydrophobic properties. Furthermore, alkyl-modified organopolysiloxane is more hydrophobic with respect to water than methylphenylpolysiloxane, and methylphenylpolysiloxane tends to be more easily cleaned. Therefore, from the viewpoint of obtaining more effective cleaning properties of the detergent composition (S) against silicone oil, methylphenylpolysiloxane is preferred as the silicone oil.

[0086] Examples of inks used in pad printing include thermosetting resins. For example, resins that harden when heated at 80 to 180°C for about 10 to 80 minutes are preferred. Examples of such thermosetting resins include polyester resins, alkyd resins, acrylic resins, vinyl resins, epoxy resins, polyol resins, melamine resins, phthalic acid resins, silicone resins, fluororesins, and polyurethane resins. Thermosetting resins may be used individually or in combination of two or more types.

[0087] Furthermore, the ink may be one that hardens using infrared, ultraviolet, or laser irradiation alone or in combination, or by a combination of these methods and heat curing, or one that dries by oxidative polymerization due to the evaporation of the solvent in the ink and oxygen in the air. In this specification, resin compounds used for decoration in pad printing are defined and referred to as "inks," and resin compounds used for undercoat and topcoat coatings are defined and referred to as "paints." No distinction is made based on the components contained or their ratios.

[0088] <(K8) process> The (K8) process is a process for cleaning the wheel substrate after pad printing (hereinafter also referred to as the "cleaning process"). The (K8) process is intended to clean and remove pad-derived components and adhesive tape residue that have adhered to the surface of the wheel base in the (K7) process. Pad-derived components include silicone oil contained in the pad, dirt, dust, etc. The adhesive tape residue is the adhesive that forms the adhesive layer of the adhesive tape used for cleaning the pads used in pad printing. The adhesive adheres to the pad prior to pad printing, and then adheres to the printed surface of the substrate during pad printing. The (K8) process includes, for example, the (K8-1) process, the (K8-2) process, and the (K8-3) process, as shown in Figure 6.

[0089] Step (K8-1) is a cleaning step in which the wheel substrate after pad printing is cleaned using the cleaning agent composition (S) of the present invention described above. In step (K8-1), the wheel substrate after pad printing is cleaned by bringing the cleaning agent composition (S) into contact with the wheel substrate after pad printing. Specifically, the wheel substrate after pad printing is cleaned by immersing it in the cleaning agent composition (S) (immersion cleaning) or by spraying the cleaning agent composition (S) onto the wheel substrate after pad printing (shower cleaning). Note that process (K8-1) is also called the "fourth cleaning process".

[0090] (K8-1) The process may be performed once or two or more times. (K8-1) When the process is performed two or more times, a different detergent composition (S) may be used for the first time and for the second time and beyond, or the same detergent composition (S) may be used. Also, the cleaning conditions may be changed for the first time and for the second time and beyond, or they may be the same. The detergent composition (S) may be used at room temperature or heated. If heated, a temperature of 40-60°C is preferred.

[0091] Step (K8-2) is the washing step. Step (K8-2) is a process aimed at removing dirt adhering to the wheel base and any remaining residue of the cleaning agent composition (S) used in step (K8-1). In step (K8-2), the wheel substrate after pad printing is cleaned by bringing it into contact with cleaning water such as tap water, industrial water, or pure water. Specifically, the wheel substrate after pad printing is cleaned by immersing it in the cleaning water (immersion cleaning) or by spraying the cleaning water onto the wheel substrate after pad printing (shower cleaning). Note that process (K8-2) is also called the "fifth cleaning process".

[0092] (K8-2) The process may be performed once or two or more times. (K8-2) If the process is performed more than once, the washing conditions may be changed between the first and subsequent washes, or they may be the same. The washing water may be used at room temperature or it may be heated. If heated, the temperature should preferably be between 40 and 80°C. In (K8-2), methods such as incorporating air into the cleaning water, using a combination of ultrasonic and vibration cleaning methods, and wiping with a cloth soaked in cleaning water can also be employed to improve cleaning power.

[0093] The order of steps (K8-1) and (K8-2) may be reversed, but it is preferable to perform step (K8-2) after step (K8-1). Furthermore, at least one of the cleaning agent composition (S) used in step (K8-1) and the cleaning water used in step (K8-2) may contain room temperature air or heated air. By incorporating air into the cleaning agent composition (S) and the cleaning water, a cleaning effect can be obtained by trapping dirt on the surface of the air bubbles and by the trapping air bubbles separating from the cleaning surface, thereby improving cleaning performance. As a result, the processing time can be shortened, and the occurrence of discoloration and peeling of the first undercoat film formed in step (K3) and the second undercoat film formed in step (K6) due to the effects of the cleaning agent composition (S) and dirt can be reduced. In addition, by shortening the processing time, the influence of the cleaning agent composition (S) on the first undercoat film and the second undercoat film can be reduced, and a decrease in adhesion between the coating film and the wheel substrate can be suppressed, which is required in the usage environment of vehicle wheels, such as "water resistance in rainy weather," "chemical resistance to cleaning agents used during car washing and de-icing agents used in snowy areas," and "weather resistance due to outdoor use." Furthermore, cleaning methods combining ultrasound and vibration, and methods involving wiping with a cloth impregnated with a cleaning agent composition (S) can also be employed.

[0094] Step (K8-3) is a drying step. Step (K8-3) is a process aimed at evaporating moisture. While there are no particular limitations on the drying method, examples include methods such as baking the wheel base or using air blowing.

[0095] <(K9) process> Step (K9) is the process of painting the wheel base after cleaning (hereinafter also referred to as the "topcoat painting process"). In step (K9), a topcoat is formed on the surface (printing surface) on which the ink layer is formed. Examples of topcoat paints used in the (K9) process include glossy clear paint, matte clear paint, and colored clear paint. In other words, the topcoat film may be a glossy clear layer, a matte clear layer, or a colored clear layer. Furthermore, the topcoat paint may be a paint that hardens by using infrared, ultraviolet, or laser irradiation alone or in combination, or by a combination of these methods and thermosetting, or a paint that dries by the evaporation of solvents in the paint and oxidative polymerization by oxygen in the air. The topcoat is also called the "top clear layer." After applying the topcoat, the topcoat film is usually cured and dried by methods such as baking. After the top clear layer is formed, there may or may not be a step between the printed area and the non-printed area, but it is preferable that there is no step.

[0096] <(K10) process> (K10) is a process for post-treatment of the wheel base after painting (hereinafter also referred to as the "post-treatment process"). In the (K10) process, for example, manufacturing lot identification and inspection are carried out. The methods for identifying manufacturing lots and the inspection methods shall be carried out by at least one of a person and a machine such as a robot.

[0097] <Effects and Effects> In the vehicle wheel manufacturing method described above, the wheel substrate is cleaned using the cleaning agent composition (S) of the present invention after pad printing, so that components derived from the pad and adhesives from adhesive tapes that adhere to the printed surface after pad printing can be thoroughly cleaned. Therefore, even if the printed surface is painted with a topcoat after cleaning with the cleaning agent composition (S), the topcoat paint is less likely to be repelled, and a uniform topcoat film can be easily formed. Furthermore, since the cleaning agent composition (S) does not easily dissolve the ink layer formed by pad printing, the decoration applied to the wheel substrate, which is the printed material, can be well maintained. Since the cleaning agent composition (S) does not easily dissolve the non-printed areas of printed materials, it has little impact on the required dimensional accuracy. For example, it is possible to easily manufacture vehicle wheels that meet dimensional accuracy on the order of ±100ths of a millimeter (0.01 mm). [Examples]

[0098] The photosensitive coloring composition of the present invention will be described below with reference to specific examples. The present invention is not limited to the following examples unless it exceeds the gist of the invention. Examples 8, 9, 11, 13, 15, 17-22, 24-27, and 29-32 are examples, while examples 1-7, 10, 12, 14, 16, 23, and 28 are comparative examples.

[0099] The compounds used in the preparation of the detergent composition are as follows: A-1: Dipropylene glycol monomethyl ether (manufactured by Kanto Chemical Co., Ltd., trade name "Dipropylene glycol monomethyl ether", isomer mixture). A-2: Diethylene glycol dimethyl ether (manufactured by Kanto Chemical Co., Ltd., product name "Diethylene glycol dimethyl ether"). B-1: Sodium hydroxide (manufactured by Kanto Chemical Co., Ltd., product name "Sodium Hydroxide", Grade 1). • C-1: Sodium cumenesulfonate (manufactured by Zen Chemical Co., Ltd., product name "Sodium Cumenesulfonate"). C-2: Polyoxyalkylene alkyl ether (manufactured by Sanyo Chemical Industries, Ltd., product name "Naroacty CL-140"). • C-3: Polyoxyethylene isocetyl ether (manufactured by Nippon Emulsion Co., Ltd., product name "EMALEX 1625"). • C-4: Sorbitan oleate (manufactured by Nippon Emulsion Co., Ltd., product name "EMALEX SPO-100"). • C-5: Polyoxyethylene decyltetradecyl ether (manufactured by Nippon Emulsion Co., Ltd., product name "EMALEX 2405").

[0100] [Preparation of primer paint] A primer was prepared by mixing paint (manufactured by Nippon Paint Automotive Coatings Co., Ltd., product name "Super Rack 5000 AS-70 11BK19") and diluent thinner (manufactured by Nippon Paint Automotive Coatings Co., Ltd., product name "N Thinner 147") in a paint:thinner ratio of 1:0.6 (by mass).

[0101] [Preparation of topcoat paint] A topcoat paint was prepared by mixing paint (manufactured by Nippon Paint Automotive Coatings Co., Ltd., product name "SP5000 AW-10 Clear") and diluent thinner (manufactured by Nippon Paint Automotive Coatings Co., Ltd., product name "N Thinner 147") in a paint:thinner ratio of 1:0.6 (by mass).

[0102] [Preparation of ink for pad printing] Pad printing ink was prepared by mixing ink (manufactured by Jujo Chemical Co., Ltd., product name "DM-D Ink Red"), a hardener (manufactured by Jujo Chemical Co., Ltd., product name "JA-950 Hardener"), and a solvent (manufactured by Jujo Chemical Co., Ltd., product name "DM Quick-Drying Solvent") in a ratio of ink:hardener:thinner = 1:0.1:0.2 (by mass).

[0103] [Measurement and Evaluation] <Evaluation of cleanability> The condition of the topcoat film was visually observed, and the cleanability was evaluated according to the following criteria. If the topcoat film was not repelled, it was judged to have excellent cleanability. ○: The topcoat film is not repelled, and the coating is uniform. ×: The topcoat film has been repelled, resulting in an uneven coating.

[0104] <Evaluation of chemical resistance> After immersion cleaning with a cleaning agent composition, the ink layer was rubbed with a paper rag before shower rinsing with pure water. The adhesion of ink to the paper rag was visually observed, and the chemical resistance was evaluated according to the following criteria. If no ink adhered to the paper rag, it was determined that the ink layer was unlikely to dissolve. Note that if the paper rag and ink were of the same color family, it would be difficult to visually distinguish them when they adhered. Therefore, the evaluation was conducted using combinations of different color tones for the paper rag and ink, where the adhesion of ink to the paper rag was clearly distinguishable. In addition, white paper rags (manufactured by Nippon Paper Crecia Co., Ltd., product name "Kimwipe Pulp, 200 sheets / box, pop-up type") were used in this evaluation. ○: No ink has adhered to the paper rag. ×: Ink has adhered to the paper rag.

[0105] <Evaluation of dimensional effects> The weight of the cut pieces of the wheel base before and after cleaning is measured to determine the weight difference, and 1m 2 The weight change per unit was calculated, and the dimensional effect was evaluated according to the following evaluation criteria. From equation (i) above, 1m 2 Weight change per unit: 27g / m 2 If the thickness is less than 0.005 mm, the non-printed areas of the printed material are less likely to dissolve, and it can be said that the dimensional accuracy is on the order of ±100ths of a millimeter (0.01 mm). However, if the required dimensional accuracy is the diameter of the inner diameter of the hub hole of an aluminum wheel, it will be the distance between the two ends of the inner diameter of the hub hole. In order to meet the dimensional accuracy on the order of ±100ths of a millimeter (0.01 mm), the thickness variation on each side must be less than 0.005 mm. In such cases, 1 m 2 The weight change per unit is 13.5 g / m². 2 If it is less than this, it can be judged that the dimensional accuracy is on the order of ±100ths of a millimeter (0.01 mm). Note that the weight difference and 1 m 2 The weight change per unit will be rounded to the sixth decimal place. ○: 1m 2 The weight change per unit is 13.5 g / m². 2 It is less than. ×: 1m 2 The weight change per unit is 13.5 g / m². 2 That's all.

[0106] <Evaluation of ease of handling> The flash point of the cleaning agent composition was measured using one of the following methods: Tagben, Setaen, or Clevelanden open. Handling was then evaluated according to the following criteria. If a composition had no flash point, it was classified as a non-hazardous material under the Fire Service Act and was deemed to have excellent handling properties. ○: Does not have a flash point. ×: Has a flash point.

[0107] "Test 1" [Examples 1-3] Pure water was used as the detergent composition. An aluminum alloy base material was coated with a primer paint, baked and dried at 140°C for 20 minutes, and then cooled to room temperature to obtain a wheel base material with a primer coating film formed on it. Next, a pad (manufactured by Space Systems Co., Ltd., product name "Silicone Pad YA-5") was pressed onto adhesive tape (manufactured by 3M Japan Limited, product name "3M Masking Tape 243J Plus 143N") to remove lint, hair, and other dust adhering to the pad. Then, pad printing ink was applied, and the ink-coated pad was pressed onto the primer coating of the wheel base. After baking and drying at 140°C for 20 minutes, it was cooled to room temperature to form an ink layer. Next, the wheel substrate after pad printing was immersed in the cleaning agent composition, which had been heated to the temperature shown in Table 1, for 90 seconds for immersion cleaning. After that, it was shower-washed with pure water for 90 seconds to remove the cleaning agent composition. Then, it was drained and dried at 110°C for 10 minutes and cooled to room temperature. Next, the topcoat paint was applied to the printed surface of the cleaned wheel base, baked and dried at 140°C for 20 minutes, and then cooled to room temperature to form a topcoat film, resulting in a vehicle wheel. This was used as the test specimen. The cleanability of the obtained test specimens was evaluated. The results are shown in Table 1.

[0108] [Examples 4-30] Detergent compositions were prepared by mixing each component to achieve the composition shown in Tables 1-5. A blank space in the amount column indicates that the component was not included (0% by mass). Test specimens were prepared in the same manner as in Example 1, except that the wheel substrate after pad printing was immersed for 90 seconds in a cleaning agent composition heated to the temperatures shown in Tables 1-5 for immersion cleaning. The obtained test specimens were evaluated for their cleanability, chemical resistance, and handling. The results are shown in Tables 1-5. A "-" indicates that an evaluation was not performed.

[0109] In the dimensional effect test, the unpainted wheel base was cleaned by scrubbing with an air blower and brush to remove dirt and dust, and then cut to obtain wheel base cut pieces. Next, the wheel base cut pieces were immersed in thinner and scrubbed with a brush to remove dirt and dust that could not be removed in the preceding steps. Then, the thinner and dirt were removed again by air blowing, and the pieces were heated and dried at 110°C for 10 minutes to evaporate the solvent and moisture, and then cooled to room temperature. Next, the surface area and weight of the wheel base cut pieces were measured, and these values ​​were taken as the weight of the wheel base cut piece before cleaning. Subsequently, after ensuring that no dirt or dust adhered to the wheel substrate, the cut pieces were immersed for 90 seconds in the cleaning agent composition heated to the temperatures shown in Tables 1-5. The cleaning agent composition was then removed by showering with pure water for 90 seconds. Next, the pieces were drained and dried at 110°C for 10 minutes, and then cooled to room temperature. These were used as test specimens for the dimensional effect test. The weight of the obtained test specimens was measured, and this value was used as the weight of the wheel base cut piece after cleaning. Dimensional effect evaluation was then performed. The results are shown in Tables 1-5. If evaluation was not performed, it is indicated with "-".

[0110] [Table 1]

[0111] [Table 2]

[0112] [Table 3]

[0113] [Table 4]

[0114] [Table 5]

[0115] As is clear from the results in Tables 1-5, the cleaning agent compositions obtained in Examples 8, 9, 11, 13, 15, 17-22, 24-27, 29, and 30 were classified as non-hazardous materials under the Fire Service Act, exhibited excellent cleaning properties against pad-derived components and adhesives of adhesive tapes, and were able to form a uniform topcoat on the wheel substrate after cleaning. Furthermore, these cleaning agent compositions were less likely to dissolve the ink layer formed by pad printing and the non-printed areas of the printed material. On the other hand, in Examples 1-3, where pure water was used as the cleaning agent composition, the cleaning performance was poor, and a uniform topcoat film could not be formed on the wheel substrate after cleaning. The cleaning agent compositions obtained in Examples 4 and 5 were able to form a uniform topcoat on the wheel base after cleaning. However, when the dimensional effect was evaluated and the inner diameter of the hub hole was taken into account, the dimensional accuracy was not on the order of ±100ths of a millimeter (0.01 mm). The cleaning agent composition obtained in Example 6 was able to form a uniform topcoat film on the wheel substrate after cleaning, but it was classified as a hazardous material under the Fire Service Act.

[0116] "Test 2: Pad Press Test" The amount of silicone oil adhering to the substrate during pad printing was measured as follows. The results are shown in Table 6. An aluminum alloy base material was coated with a primer paint, baked and dried at 140°C for 20 minutes, and then cooled to room temperature to obtain a wheel base material with a primer coating film formed on it. The wheel base was cut, and the weight of the cut piece was measured. The dimensions of the wheel base piece were 70 mm wide and 75 mm long, with a surface area of ​​5250 mm². 2 That was the case. Next, a pad (manufactured by Space Systems Co., Ltd., product name "Silicone Pad YA-5") was pressed onto a cut piece of the wheel base, and the weight of the wheel base cut piece was measured each time the pad was pressed. For 1 to 12 presses, the pad was pressed on the same spot. For 48 presses, the pad was pressed 12 times on each of four different spots. In pad printing, it is common to press the pad 1 to 3 times before printing, but in this test, assuming printing on multiple spots and multiple times, 48 ​​presses was used as the amount of silicone oil deposited as a result of pad printing. The amount of silicone oil applied was determined from the difference between the weight of the wheel base piece before the pad was pressed and the weight of the wheel base piece after the pad was pressed.

[0117] [Table 6]

[0118] As is clear from the results in Table 6, the amount of silicone oil adhering during pad printing was 0.00008 g, and 1 mm 2 The amount of silicone oil applied per unit is approximately 0.000000015 g / mm³. 2 (Rounded to 10 decimal places). Regarding the fact that the amount of adhesive applied after pressing the pad 11 times was less than after the 10th time, we determined that this was because the silicone oil had adhered to the pad, resulting in a lighter weight.

[0119] "Test 3: Oil Adhesion Test" [Examples 31, 32] Methylphenylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KF-54") was used as the silicone oil. As the detergent composition, in Example 31, the detergent composition obtained in Example 9 was used after being heated to 40°C, and in Example 32, the detergent composition obtained in Example 19 was used after being heated to 50°C. Silicone oil was soaked into paper wipes (manufactured by Nippon Paper Crecia Co., Ltd., product name "Kimwipes Pulp, 200 sheets / box, pop-up type").

[0120] An aluminum alloy base material was coated with a primer paint, baked and dried at 140°C for 20 minutes, and then cooled to room temperature to obtain a wheel base material with a primer coating film formed on it. The wheel base was cut, and the weight of the cut piece was measured. This value was taken as the weight before oil was applied. The dimensions of the wheel base cut piece were 35 mm wide and 25 mm long, with a surface area of ​​875 mm². 2 That was the case. Next, one side of the wheel base piece was wiped with a paper rag soaked in silicone oil, thereby adhering the silicone oil to the other side of the wheel base piece. The weight of the wheel base piece after application was measured, and this value was defined as the weight after oil application. The amount of silicone oil applied was determined by the weight difference between the wheel base cut piece before and after application of the silicone oil. 2 The amount of silicone oil applied per unit was determined. The results are shown in Table 7. Furthermore, the 1 mm determined in Test 2 (pad pressure test) 2 The amount of silicone oil applied per unit area, as determined in Test 3 (oil adhesion test) 2 The ratio of silicone oil application per unit was calculated using the following formula (ii). The results are shown in Table 7. Ratio of oil adhesion amount = 1 mm as determined in Test 3 2 Amount of silicone oil applied per unit / 1 mm as determined in Test 2 2 Amount of silicone oil applied per unit...(ii)

[0121] Next, the wheel substrate cut pieces, to which silicone oil had been applied, were immersed in a heated cleaning agent composition for 90 seconds for immersion cleaning, and then shower-washed with pure water for 90 seconds to remove the cleaning agent composition. After that, they were drained and dried at 110°C for 10 minutes and then cooled to room temperature. Next, a topcoat paint was applied to one side of the cleaned wheel substrate cut piece (the side to which silicone oil was applied), baked and dried at 140°C for 20 minutes, and then cooled to room temperature to form a topcoat film, which was then used as a test piece. The cleanability of the obtained test specimens was evaluated. The results are shown in Table 7.

[0122] [Table 7]

[0123] As is clear from the results in Table 7, the cleaning agent compositions obtained in Examples 9 and 19 exhibited excellent cleaning properties even when silicone oil was actively applied, and were able to form a uniform topcoat on the wheel substrate cut pieces after cleaning. Note that 1 mm when silicone oil is actively applied 2 The amount of silicone oil adhering per unit (oil adhesion test) is measured per 1 mm of the printed surface during pad printing. 2 The amount of silicone oil adhering to the pad (pad press test) was approximately 45 times greater. Therefore, the evaluation of cleanability in Test 3 can be considered acceptable as an evaluation test for the cleanability of silicone oil adhering during pad printing. [Explanation of symbols]

[0124] 10A Wheel Base 10B Wheel Base 10C Wheel Base 10D Wheel Base 10E Wheel Base 10F Wheel base 10G Wheel Base 11 Wheel base material 12. Chemical conversion coating 13. Primer layer 14. First colored base layer 15. Second colored base layer 16 Metal reflective film 17. Color Clear Layer 18. Top Clear Coat

Claims

1. A cleaning agent composition used for vehicle wheels, (A) Components: Glycol ether and (B) Components: Sodium hydroxide and (D) Ingredients: Water and It contains, The content of component (A) is 19 to 60% by mass, the content of component (B) is 5 to 13% by mass, and the content of component (D) is 20% by mass or more, based on the total mass of the detergent composition. A detergent composition that is substantially free of surfactants.

2. A cleaning agent composition used for vehicle wheels, (A) Components: Glycol ether and (B) Components: Sodium hydroxide and (C) Ingredients: Surfactants and (D) Ingredients: Water and It contains, A detergent composition wherein, with respect to the total mass of the detergent composition, the content of component (A) is 0.1 to 60% by mass, the content of component (B) is 0.1 to 60% by mass, the content of component (C) is 1 to 75% by mass, and the content of component (D) is 20% by mass or more.

3. The detergent composition according to claim 1 or 2, wherein component (A) comprises dipropylene glycol monomethyl ether.

4. A method for manufacturing a vehicle wheel, comprising the steps of: pad printing a wheel base; cleaning the pad-printed wheel base using the cleaning agent composition described in claim 1 or 2; and painting the cleaned wheel base.

5. The method for manufacturing a vehicle wheel according to claim 4, wherein the cleaning agent composition is heated to 40 to 60°C to clean the wheel substrate after pad printing.

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