Emulsion composition for buff polishing, and buff polishing method

Abstract

To provide a buff polishing emulsion composition and the like excellent in polishing and finishing properties.SOLUTION: The present invention is a buff polishing emulsion composition containing water, lubricating oil, an organic solvent, abrasive particles, and a surfactant, wherein the abrasive particles include tin(IV) oxide particles (A) with an average particle diameter of 1.2 to 1.6 μm and tin(IV) oxide particles (B) with an average particle diameter of 0.5 to 0.9 μm. The total content of tin(IV) oxide particles (A) and tin(IV) oxide particles (B) in the buff polishing emulsion composition is 5 to 10 wt.%, and the content ratio of tin(IV) oxide particles (A) to tin(IV) oxide particles (B) is 5:5 to 8:2 by weight. The organic solvent includes an isoparaffinic hydrocarbon.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an emulsion composition for buffing and a buffing method, more specifically to an emulsion composition used as an abrasive in a buffing step carried out to smooth a coating film after top coating in painting work for repairing sheet metal of automobiles and the like, and a buffing method using the emulsion composition. [Background technology]

[0002] In painting work for repairing sheet metal on automobiles, etc., after the top coat is applied, the paint film is sanded with wet sandpaper and buffed to a smooth finish similar to that of a new car. In particular, when buffing, it is required to achieve a high level of polishing to the point where the polished areas cannot be detected visually.

[0003] In general buffing, a wool buff is used in the rough polishing process to polish and repair the marks left by the paper removing dirt and impurities (paper scratches), and at the same time polish and smooth the surrounding painted surface.After that, a sponge buff is used in the next finish polishing process to repair the polishing marks (buff marks) from the rough polishing process, resulting in a high-quality finish that is not visible to the naked eye.

[0004] Patent Document 1 describes a polishing composition suitable for buffing the surface of an automobile coating, which contains at least water, abrasive grains, a petroleum-based solvent, a surfactant, and a thickener, and further contains 0.1 to 20 wt. % of a plasticizer.

[0005] Patent Document 2 describes an emulsion composition for buffing containing water, a lubricating oil, an organic solvent, abrasive particles, and a surfactant, wherein the lubricating oil contains an oil or fat containing a triglyceride of an unsaturated fatty acid, the organic solvent contains a glycol ether solvent, the abrasive particles contain stannic oxide particles having an average particle size of 0.5 to 5 μm and alumina particles having an average particle size of 5 to 20 μm, the content of the stannic oxide particles in the emulsion composition for buffing being 12 to 20 wt % and the content of the alumina particles being 15 to 40 wt %, and the content of the alumina particles being greater than the content of the stannic oxide particles. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-193658 [Patent Document 2] Japanese Patent Publication No. 2022-59127 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, self-repairing coatings (also called "self-repairing scratch-resistant coatings") used as coatings on the bodies of luxury cars and the like are made of resins with low glass transition temperatures, and when heated, they easily rise above their glass transition temperature and soften, and when cooled below their glass transition temperature, they shrink. With conventional polishing compositions, polishing of such self-repairing coating films takes a long time, and the polishing may not be completed before the temperature exceeds the glass transition temperature due to frictional heat during polishing, resulting in poor polishing efficiency and inability to polish the film completely. Furthermore, it was found that conventional polishing compositions have insufficient finishability after polishing. In particular, when the base of the coating film is black, insufficient finishability results in a hazy white finish, and a clear finish cannot be achieved. Furthermore, polishing compositions that are excellent in polishing properties and finishability are required not only for polishing self-repairing coating films but also for polishing other coating films, but this has not been fully investigated to date.

[0008] Therefore, an object of the present invention is to provide an emulsion composition for buffing that has excellent abrasive properties and finishability. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that an emulsion composition containing a specific organic solvent and specific amounts of two types of specific stannic oxide particles with different average particle sizes has excellent polishing properties and finishing properties, leading to the completion of the present invention.

[0010] That is, the present invention provides an emulsion composition for buffing, which comprises water, a lubricating oil, an organic solvent, abrasive particles, and a surfactant, the abrasive particles contain stannic oxide particles (A) having an average particle size of 1.2 to 1.6 μm and stannic oxide particles (B) having an average particle size of 0.5 to 0.9 μm; the total content of the stannic oxide particles (A) and the stannic oxide particles (B) in the emulsified composition for buffing is 5 to 10% by weight, the weight ratio of the stannic oxide particles (A) to the stannic oxide particles (B) is 5:5 to 8:2, The present invention relates to an emulsion composition for buffing, wherein the organic solvent comprises an isoparaffinic hydrocarbon. The present invention also provides a method for polishing a coating film, comprising: The present invention also relates to a buffing method, which comprises a finish polishing step of polishing the coating film polished in the rough polishing step using the emulsion composition for buffing. [Effects of the Invention]

[0011] According to the present invention, an emulsion composition for buffing that is excellent in abrasiveness and finishability can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present invention will be described below.

[0013] <Emulsion composition for buffing> The emulsified composition for buffing according to this embodiment contains water, a lubricating oil, an organic solvent, abrasive particles, and a surfactant. The abrasive particles include stannic oxide particles (A) having an average particle size of 1.2 to 1.6 μm and stannic oxide particles (B) having an average particle size of 0.5 to 0.9 μm. The total content of the stannic oxide particles (A) and the stannic oxide particles (B) in the emulsified composition for buffing is 5 to 10% by weight. The weight ratio of the stannic oxide particles (A) to the stannic oxide particles (B) is 5:5 to 8:2. The organic solvent includes an isoparaffinic hydrocarbon.

[0014] (lubricating oil) The emulsion composition for buffing according to this embodiment contains a lubricating oil. This allows the emulsion composition for buffing to have good polishing properties and good finishing properties. Only one type of lubricating oil may be used, or two or more types may be used in combination.

[0015] The content of the lubricating oil can be set as appropriate, but from the viewpoint of achieving both polishing performance and finishing performance, it is preferably 1 to 15% by weight, more preferably 2 to 10% by weight, and even more preferably 4 to 8% by weight of the entire emulsion composition for buffing.

[0016] The lubricating oil preferably contains a fat or oil containing a triglyceride of an unsaturated fatty acid, which allows the emulsion composition for buffing to have good polishing properties and good finishing properties.

[0017] The fats and oils containing triglycerides of unsaturated fatty acids preferably contain unsaturated fatty acids with a carbon number of 18. Fat and oils containing triglycerides of unsaturated fatty acids with a carbon number of 18 are generally found in large amounts in natural vegetable fats and oils. Unsaturated fatty acids with a carbon number of 18 are any of oleic acid (one unsaturated double bond in the molecule), ricinoleic acid (one unsaturated double bond and one hydroxyl group in the molecule), linoleic acid (two unsaturated double bonds in the molecule), and linolenic acid (three unsaturated double bonds in the molecule), and they exist as oleic acid triglyceride, ricinoleic acid triglyceride, linoleic acid triglyceride, and linolenic acid triglyceride, respectively. The oils and fats may be used alone or in combination of two or more.

[0018] Oleic acid triglyceride is typically found in high concentrations in olive oil (70-80%), rapeseed oil (low oleic / 60-70%), safflower oil (high oleic / 70-80%), sunflower oil (high oleic / 80-90%), tea seed oil (80-90%), almond oil (60-70%), avocado oil (60-70%), peanut oil (50-60%), and pearl millet oil (50-60%). It is also found in palm oil, rice bran oil, sesame oil, corn oil, cottonseed oil, borage seed oil, soybean oil, linseed oil, and grape oil, and in small amounts in coconut oil, castor oil, and tung oil.

[0019] Ricinoleic acid triglyceride is found in large amounts in castor oil (80-90% content).

[0020] Linoleic acid triglyceride is typically found in high concentrations in safflower oil (high linoleic / 70-80% content), grape oil (70-80%), evening primrose oil (70-80%), walnut oil (60-70%), sunflower oil (50-60%), soybean oil (50-60%), cottonseed oil (50-60%), corn oil (50-60%), and wheat germ oil (50-60%). It is also found in rosehip oil, borage seed oil, rice bran oil, sesame oil, peanut oil, adlay oil, rapeseed oil, linseed oil, and palm oil, and in small amounts in olive oil, tung oil, castor oil, and coconut oil.

[0021] Linolenic acid triglyceride is typically found in high amounts in tung oil (80-90% content), linseed oil (50-60%), perilla oil (55-65%), and perilla seed oil (60-70%), but is also found in rosehip oil, borage seed oil, and walnut oil, and in small amounts in rapeseed oil, evening primrose oil, soybean oil, rice bran oil, corn oil, and castor oil.

[0022] Among these, fats and oils containing ricinoleic acid triglyceride are preferred, and castor oil is particularly preferred.

[0023] The content of the oils and fats containing the triglycerides of unsaturated fatty acids can be set as appropriate, but from the viewpoint of achieving both polishing properties and finishing properties, it is preferably 0.05 to 5.0 wt % of the total emulsion composition for buffing, more preferably 0.10 to 1.0 wt %, and even more preferably 0.25 to 0.60 wt %.

[0024] The lubricating oil preferably further contains glycerin and liquid paraffin in addition to the oil containing the triglyceride of unsaturated fatty acid. Liquid paraffin refers to a paraffin that is liquid at room temperature and whose main component is an alkane having 20 or more carbon atoms. Only one type of liquid paraffin may be used, or two or more types may be used in combination.

[0025] The content ratio of glycerin to liquid paraffin can be set as appropriate, but is preferably 2:98 to 20:80 by weight, more preferably 4:96 to 12:88. The weight ratio of the fat and oil containing triglyceride of unsaturated fatty acid to the total amount of glycerin and liquid paraffin (amount of fat and oil: (amount of glycerin + amount of liquid paraffin)) is preferably 2:98 to 20:80, more preferably 4:96 to 12:88.

[0026] The total content of the oils and fats containing triglycerides of unsaturated fatty acids, glycerin, and liquid paraffin can be set as appropriate, but from the viewpoint of achieving both polishing performance and finishing performance, it is preferably 1 to 15% by weight, more preferably 2 to 10% by weight, and even more preferably 4 to 8% by weight of the entire emulsion composition for buffing.

[0027] (organic solvent) The emulsion composition for buffing according to this embodiment contains an organic solvent, and the organic solvent contains at least an isoparaffinic hydrocarbon. By using the isoparaffinic hydrocarbon in combination with the stannic oxide particles (A) and the stannic oxide particles (B), it is possible to achieve both polishing properties and finishability.

[0028] The content of isoparaffinic hydrocarbons can be set as appropriate, but from the viewpoint of achieving both polishing performance and finishing performance, it is preferably 0.3 to 15 wt % of the entire emulsion composition for buffing, more preferably 0.5 to 10 wt %, even more preferably 1.0 to 8.0 wt %, and even more preferably 2.0 to 5.0 wt %.

[0029] The emulsion composition for buffing according to the present embodiment may contain only isoparaffinic hydrocarbons as the organic solvent, or may contain other organic solvents in addition to isoparaffinic hydrocarbons. The other organic solvent is not particularly limited, but examples thereof include petroleum-based aliphatic solvents such as kerosene, solvent naphtha, and industrial volatile oil; normal paraffins such as nonane, decane, and dodecane; saturated aliphatic hydrocarbons such as naphthene (including monoenes and dienes having partially unsaturated bonds); terpene-based solvents such as camphor oil, turpentine oil, and pine oil; terpenes such as pinene and dipentene; and glycol ether-based solvents such as ethylene glycol monomethyl ether and diethylene glycol monomethyl ether. The emulsion composition for buffing according to this embodiment preferably contains naphthene as an organic solvent in addition to the isoparaffinic hydrocarbon in order to further enhance the polishing properties. From the viewpoint of finishability, it is preferable that the amount of isoparaffinic hydrocarbons is greater than that of naphthenes. The weight ratio of isoparaffinic hydrocarbons to naphthenes is preferably 51:49 to 99:1, more preferably 60:40 to 90:10.

[0030] (abrasive particles) The emulsion composition for buffing according to this embodiment contains, as abrasive particles, at least stannic oxide particles (A) having an average particle size of 1.2 to 1.6 μm and stannic oxide particles (B) having an average particle size of 0.5 to 0.9 μm. It is believed that the stannic oxide particles (A) have a large average particle size and therefore enhance polishing properties, while the stannic oxide particles (B) have a small average particle size and therefore enhance finishability. The average particle size in this application refers to the 50% volume average particle size.

[0031] The average particle size of the stannic oxide particles (A) is 1.2 to 1.6 μm, preferably 1.3 to 1.5 μm, and more preferably 1.35 to 1.45 μm. When the average particle size of the stannic oxide particles (A) is 1.2 μm or more, polishing properties are improved, and when the average particle size of the stannic oxide particles (A) is 1.6 μm or less, finishability is improved. The average particle size of the stannic oxide particles (B) is 0.5 to 0.9 μm, preferably 0.6 to 0.8 μm, and more preferably 0.65 to 0.75 μm. When the average particle size of the stannic oxide particles (B) is 0.5 μm or more, polishing properties are improved, and when the average particle size of the stannic oxide particles (A) is 0.9 μm or less, finishability is improved.

[0032] The total content of the stannic oxide particles (A) and the stannic oxide particles (B) in the emulsified composition for buffing is 5 to 10% by weight, preferably 5.5 to 9.5% by weight, and more preferably 6.0 to 9.0% by weight. If the total content is too low, sufficient polishing power cannot be obtained, and conversely, if the total content is too high, it becomes difficult to uniformly disperse the particles in the composition, polishing scratches are likely to occur, and finishability tends to deteriorate.

[0033] The weight ratio of the stannic oxide particles (A) to the stannic oxide particles (B) is 5:5 to 8:2, and more preferably 6:4 to 7:3. If the content ratio of stannic oxide particles (A) is low, sufficient polishing power cannot be obtained, and conversely, if the content ratio of stannic oxide particles (B) is low, polishing scratches tend to occur easily and finishability tends to deteriorate.

[0034] From the viewpoint of further improving polishing properties and finishability, in the emulsion composition for buffing according to this embodiment, it is particularly preferred that the stannic oxide particles (A) have an average particle size of 1.35 to 1.45 μm, the stannic oxide particles (B) have an average particle size of 0.65 to 0.75 μm, and the weight ratio of the stannic oxide particles (A) to the stannic oxide particles (B) is 6:4 to 7:3.

[0035] (surfactant) The emulsion composition for buffing according to this embodiment contains a surfactant to improve the stability of the emulsion. The surfactant is not particularly limited and may be any of a nonionic surfactant, an anionic surfactant, and a cationic surfactant. Only one surfactant may be used, or two or more surfactants may be used in combination.

[0036] Preferred surfactants include polyoxyethylene sorbitan fatty acid esters and polyoxyethylene sorbitol fatty acid esters. The use of these surfactants can prevent the coating liquid from repelling when a clear coat is applied to the coating film after polishing (specifically, when the coating liquid is sprayed onto the coating film). Furthermore, they can impart gloss to the coating film after polishing. Among these, it is preferable that the fatty acid moiety is oleic acid.

[0037] Examples of polyoxyethylene sorbitan fatty acid esters or polyoxyethylene sorbitol fatty acid esters include Rheodol TW-O106 (polyoxyethylene sorbitan monooleate), Rheodol TW-O320 (polyoxyethylene sorbitan trioleate), and Rheodol 430 (polyoxyethylene sorbitan tetraoleate), all manufactured by Kao Corporation; and TO-106 (polyoxyethylene sorbitan monooleate), TO-30 (polyoxyethylene sorbitan trioleate), and GO-430 (polyoxyethylene sorbitan tetraoleate), all manufactured by Nikko Chemicals Co., Ltd.

[0038] The content of the surfactant can be set as appropriate, but is preferably 0.1 to 5.0% by weight, more preferably 0.5 to 4.0% by weight, of the entire emulsion composition for buffing.

[0039] (thickener) The emulsion composition for buffing according to this embodiment preferably contains a thickener to impart the necessary viscosity to the composition and improve the dispersion stability of the abrasive particles and the emulsion stability of the organic solvent. One type of thickener may be used alone, or two or more types may be used in combination.

[0040] Commercially available thickeners can be used, but among them, associative alkali-soluble acrylic polymers are preferred, and associative alkali-soluble acrylic polymers obtained by copolymerizing acrylic acid and acrylic acid esters are particularly preferred. Such polymers can be effective with a relatively small amount of addition and are less likely to adversely affect the polishing action. Furthermore, stable formulations can be prepared near neutral. By combining these with an appropriate alkaline agent and neutralizing them, the entire polishing emulsion composition can be freely adjusted to a low-viscosity liquid, a high-viscosity liquid, or a paste.

[0041] Examples of such thickeners include Primal RM-4, Primal RM-5, Primal TT-615, Primal TT-935, Primal TT-950 (all manufactured by Rohm and Haas Japan Co., Ltd.), Carbopol 981, Carbopol 934, Carbopol ETD2020, Carbopol EZ-1, Carbopol Ultrez 10, Carbopol Ultrez 21, PEMULENTR-1, and PEMULENTR-2 (all manufactured by BFGoodrich Corporation).

[0042] Other thickeners can also be used. Such thickeners are not particularly limited, and examples thereof include polysaccharides such as urethane-modified polyethers, polyvinyl alcohol, carboxymethyl cellulose, and xanthan gum. These may be used alone or in combination of two or more. Urethane-modified polyethers are preferred as thickeners because they provide good thickening stability to the emulsion composition for buffing.

[0043] The content of the thickener can be set as appropriate, but is preferably 0.1 to 8.0% by weight, more preferably 0.5 to 5.0% by weight, of the entire emulsion composition for buffing.

[0044] (Alkaline agent) When the emulsion composition for buffing according to this embodiment contains an associative alkali-soluble acrylic polymer as a thickener, it is preferable that the emulsion composition for buffing according to this embodiment further contains an alkali agent so that the entire emulsion composition for polishing can be freely adjusted to a low-viscosity liquid, a high-viscosity liquid, or a paste. The type of the alkaline agent is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, trimethylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, and morpholine. The content of the alkaline agent can be set as appropriate, but is preferably 0.05 to 3.0% by weight, more preferably 0.1 to 1.0% by weight, of the entire emulsion composition for buffing.

[0045] (Other optional ingredients) The emulsion composition for buffing according to this embodiment may optionally contain additives such as pigments (carbon black, etc.), dispersants, silicone oils, waxes, rust inhibitors, preservatives, antifreeze agents, fragrances, etc. However, the emulsion composition for buffing may be substantially free of silicone oil. Substantially free of silicone oil means that the content of silicone oil is less than 0.05% by weight of the entire emulsion composition for buffing. It may also be less than 0.01% by weight. After polishing, the coating film may be degreased, and an embodiment that is substantially free of silicone oil makes this degreasing easier.

[0046] (Application) The emulsion composition for buffing according to this embodiment can be used, for example, by adhering it to a buff to smooth a coating film during buffing after painting work in repairing sheet metal of an automobile or the like. Buffing includes a rough polishing step and a finish polishing step, and the emulsion composition is particularly suitable for use in the finish polishing step. The buff to which the emulsion composition is attached is usually set in a polisher to polish the coating film. The emulsion composition is particularly suitable for use in polishing self-repairing coating films.

[0047] <Method of manufacturing emulsion composition for buffing> In the method for producing the emulsified composition for buffing, the water, the lubricating oil, the isoparaffinic hydrocarbon, the stannic oxide particles (A), the stannic oxide particles (B), and the surfactant are mixed and emulsified to produce the emulsified composition for buffing. Additional components may be mixed during the mixing.

[0048] <Composition set> The composition set according to this embodiment includes a first composition, which is the emulsion composition for buffing, and a second composition, which are separate compositions. The emulsified composition for buffing, which is the first composition, is used in a finish polishing step, and the second composition is used in a rough polishing step before the finish polishing step.

[0049] The second composition preferably contains stannic oxide particles (C). The average particle size of the stannic oxide particles (C) is preferably from 1.2 to 1.6 μm, more preferably from 1.3 to 1.5 μm, and even more preferably from 1.35 to 1.45 μm. The content of the stannic oxide particles (C) in the second composition is preferably 5 to 10% by weight, more preferably 5.5 to 9.5% by weight, and even more preferably 6.0 to 9.0% by weight. The content of the stannic oxide particles (C) in the second composition is preferably greater than the content of the stannic oxide particles (A) in the emulsified composition for buffing, and is more preferably 1.10 to 5 times, even more preferably 1.20 to 3 times, and particularly preferably 1.25 to 2 times, the content of the stannic oxide particles (A) in the emulsified composition for buffing, in weight ratio. The second composition is preferably an emulsion composition. The second composition preferably contains water, a lubricating oil, an organic solvent, a surfactant, etc. Details of each of these components (compounds, blending ratios, etc.) are not particularly limited, but reference can be made to JP 2022-59127 A and the like.

[0050] <Buffing method> In the buffing method according to this embodiment, a coating film is buffed using the emulsion composition for buffing. Furthermore, the buffing method according to the present embodiment preferably includes a rough polishing step of polishing a coating film using the second composition, and a finish polishing step of polishing the coating film polished in the rough polishing step using the emulsion composition for buffing. In the rough polishing step, the second composition is applied to a wool buff and the coating film is polished. In the finish polishing step, the emulsion composition for buffing is attached to a sponge buff, and the coating film polished in the rough polishing step is polished.

[0051] It should be noted that the present invention is not limited to the above-described embodiment. Furthermore, the present invention is not limited to the above-described effects. Furthermore, the present invention can be modified in various ways without departing from the spirit of the present invention.

[0052] [Disclosure items] Each of the following sections is a disclosure of a preferred embodiment.

[0053] [Item 1] An emulsion composition for buffing, comprising water, a lubricating oil, an organic solvent, abrasive particles, and a surfactant, the abrasive particles contain stannic oxide particles (A) having an average particle size of 1.2 to 1.6 μm and stannic oxide particles (B) having an average particle size of 0.5 to 0.9 μm; the total content of the stannic oxide particles (A) and the stannic oxide particles (B) in the emulsified composition for buffing is 5 to 10% by weight, the weight ratio of the stannic oxide particles (A) to the stannic oxide particles (B) is 5:5 to 8:2, The emulsion composition for buffing, wherein the organic solvent comprises an isoparaffinic hydrocarbon. [Item 2] Item 2. The emulsion composition for buffing according to item 1, wherein the lubricating oil comprises castor oil. [Item 3] 3. The emulsion composition for buffing according to Item 2, wherein the lubricating oil further contains glycerin and liquid paraffin. [Item 4] 4. The emulsion composition for buffing according to any one of items 1 to 3, further comprising a thickener. [Item 5] 5. The emulsion composition for buffing according to any one of items 1 to 4, which is used in a finish polishing step. [Item 6] a rough polishing process for polishing the coating film; and a finish polishing step of polishing the coating film polished in the rough polishing step using the emulsion composition for buffing according to item 5. [Example]

[0054] Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0055] Example 13 The components shown in Table 1 below were mixed and emulsified to prepare an emulsion composition for buffing. As the thickener, an association-type alkali-soluble acrylic polymer (Primal TT-615) was used.

[0056] [Table 1]

[0057] (Examples 1 to 12, 14 to 45, Comparative Examples 1 to 72) An emulsion composition for buffing (total content of stannic oxide particles (A) and stannic oxide particles (B): 7.5 wt %) was prepared in the same manner as in Example 13, except that the types and weight ratios (also simply referred to as "ratios") of the stannic oxide particles (A) and stannic oxide particles (B) were changed as shown in Tables 2 to 4 below.

[0058] (Comparative Example 73) An emulsion composition for buffing was prepared in the same manner as in Example 13, except that alumina particles (alumina FINISH 0.5 μm) were used as the abrasive particles, the amount of alumina particles as the abrasive particles was set as shown in Table 4 below, and the amount of water was increased to compensate for the decrease in the amount of abrasive particles.

[0059] (Comparative Example 74) An emulsion composition for buffing was prepared in the same manner as in Example 13, except that alumina particles were used as the abrasive particles.

[0060] (Comparative Example 75) An emulsion composition for buffing was prepared in the same manner as in Example 13, except that alumina particles were used as abrasive particles, the amount of alumina particles as abrasive particles was set as shown in Table 4 below, and the amount of water was reduced by the amount of abrasive particles.

[0061] (Comparative Examples 76 to 87) An emulsion composition for buffing was prepared in the same manner as in Example 13, except that the weight ratio of the stannic oxide particles (A) and the stannic oxide particles (B) and the type of organic solvent were changed as shown in Table 4 below.

[0062] In Tables 2 to 4 below, stannic oxide particles (0.7±0.2 μm) are stannic oxide particles with an average particle diameter of 0.7 μm, and stannic oxide particles (1.4±0.2 μm) are stannic oxide particles with an average particle diameter of 1.4 μm.

[0063] <Performance evaluation> (Automotive exterior paint film reproduced on test panel) Single-sided 2-coat base clear finish Test pieces of the self-healing scratch-resistant coating were prepared by baking at 70°C for 50 minutes, followed by air drying at 25°C for 24 hours.

[0064] (Polishing procedure) First, the test piece was scratched using #3000 paper (Trecut Black 3000; manufactured by Kovacs). Next, an appropriate amount of polishing compound (also referred to as the "second composition") was applied to a wool buff, and the test piece was polished by pressing it against the scratched area for 13 seconds (polishing process (rough polishing process)). Then, an appropriate amount of finishing compound (emulsion composition for buffing of each Example or Comparative Example) was applied to a sponge buff, and the test piece was polished by pressing it against the scratch made in the polishing process for 12 seconds (finishing process (finish polishing process)). Next, the surface of the test piece was wiped with a 30% aqueous solution of 2-propanol and a dry cloth. The polishing compound was prepared in the same manner as the emulsion composition for buffing of Example 13, except that stannic oxide particles (average particle diameter: 1.4 μm) were used as the abrasive particles and the content of the stannic oxide particles (average particle diameter: 1.4 μm) was 7.5 wt %.

[0065] (Evaluation Procedure) In a dark room, the test piece was irradiated with light using Daylight 216 (illuminance: 2700 lux, manufactured by Shinyu Shoji Co., Ltd.). When exposed to light, the appearance was checked according to the following criteria.

[0066] (Evaluation criteria for abrasiveness) It was confirmed based on the following evaluation criteria whether scratches made in the polishing process (rough polishing process) could be replaced (whether polishing marks (buffing scratches) made in the polishing process could be repaired). ◎: No visible buffing scratches. Good: Small buffing scratches are visible on the edge of the lighted area. △: Partial buffing scratches are visible around the area irradiated by the light. ×: Deep circular buffing scratches are visible The results are shown in Tables 2 to 4 below.

[0067] (Evaluation criteria for finishability) The visibility of the boundary between the polished and unpolished areas was confirmed according to the following evaluation criteria. ◎: No white haze is visible. ○: A white haze is visible around the edge of the light. △: A partial white haze can be seen around the light. (Can be observed with a mercury lamp.) ×: White haze is visible. (Can be observed under mercury lamp.) The results are shown in Tables 2 to 4 below.

[0068] [Table 2]

[0069] [Table 3]

[0070] [Table 4]

[0071] As shown in Tables 2 and 4, Examples 1 to 45, which are within the scope of the present invention, exhibited good polishability and finishability. On the other hand, as shown in Tables 3 and 4, Comparative Examples 1 to 14 and 37 to 50, which had a low content ratio of stannic oxide particles (A), Comparative Examples 15, 17, 19 and 21, which had a small average particle size of stannic oxide particles (A), and Comparative Examples 51, 53, 55 and 57, which had a small average particle size of stannic oxide particles (B), had at least inferior polishing properties to the Examples. Furthermore, in Comparative Examples 23 to 36, 59 to 72 in which the content ratio of stannic oxide particles (B) was low, Comparative Examples 16, 18, 20, 22 in which the average particle diameter of stannic oxide particles (A) was large, Comparative Examples 52, 54, 56, 58 in which the average particle diameter of stannic oxide particles (B) was large, Comparative Examples 73 to 75 in which the abrasive particles did not contain stannic oxide particles, and Comparative Examples 76 to 87 in which the organic solvent did not contain isoparaffinic hydrocarbons, at least the finishability was inferior to that of the Examples. Therefore, it can be seen that the present invention can provide an emulsion composition for buffing that is excellent in abrasiveness and finishability.

Claims

1. An emulsion composition for buffing, comprising water, a lubricating oil, an organic solvent, abrasive particles, and a surfactant, the abrasive particles contain stannic oxide particles (A) having an average particle size of 1.2 to 1.6 μm and stannic oxide particles (B) having an average particle size of 0.5 to 0.9 μm; the total content of the stannic oxide particles (A) and the stannic oxide particles (B) in the emulsified composition for buffing is 5 to 10% by weight, a weight ratio of the stannic oxide particles (A) to the stannic oxide particles (B) of 5:5 to 8:2; The emulsion composition for buffing, wherein the organic solvent comprises an isoparaffinic hydrocarbon.

2. The buffing emulsion composition of claim 1 , wherein the lubricating oil comprises castor oil.

3. 3. The emulsion composition for buffing according to claim 2, wherein the lubricating oil further comprises glycerin and liquid paraffin.

4. The emulsion composition for buffing according to any one of claims 1 to 3, further comprising a thickener.

5. The emulsion composition for buffing according to any one of claims 1 to 3, which is used in a finish polishing step.

6. a rough polishing process for polishing the coating film; A buffing method comprising a finish polishing step of polishing the coating film polished in the rough polishing step using the emulsion composition for buffing according to claim 5.

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