Paint film remover

Abstract

To provide a water-based coating film remover which is excellent in coating film removability and workability and does not contain benzyl alcohol.SOLUTION: The coating film remover of the present invention is a coating film remover containing 30% by mass or more and 85% by mass or less of phenethyl alcohol or phenoxyethanol as a component (A), more than 2% by mass and 5% by mass or less of organic bentonite or hydrophobic fumed silica as a component (B), and 10% by mass or more of water as a component (C), and not containing benzyl alcohol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a paint film remover, and in particular to a paint film remover that does not contain benzyl alcohol and has excellent safety and removability. [Background technology]

[0002] The surfaces of steel structures and buildings are painted for various purposes, including structural protection, rust prevention, and aesthetics. These paints deteriorate over time, requiring periodic repainting. However, the paint film must be removed during repainting. Paint removal methods include physical methods, such as scraping the paint off with blasting or power tools, and chemical methods, such as using paint strippers to soften and remove the paint. These old paint films often contain hazardous substances, such as lead, chromium, PCBs, and asbestos. In recent years, chemical removal methods using paint strippers have become recommended because they reduce the generation of dust containing hazardous substances and enable paint removal without generating noise.

[0003] As paint film removers, chlorine-based removers containing dichloromethane as an organic solvent component (see Patent Document 1) as well as removers containing N-methyl-2-pyrrolidone or benzyl alcohol (see Patent Document 2) have been used. However, all of these compounds are designated as hazardous and harmful substances that require risk assessment under the Industrial Safety and Health Act, and there are concerns that they may be harmful to health. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2964108 [Patent Document 2] Patent No. 6193425 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, there is a need for a water-based paint stripper that does not contain compounds designated as hazardous substances and whose solvent components are less likely to volatilize. Therefore, the present inventors have been developing water-based paint strippers that contain aromatic alcohols other than benzyl alcohol as solvent components. However, while safety is ensured when aromatic alcohols other than benzyl alcohol are used as solvent components, there are problems such as poor paint stripping properties and the paint stripper being prone to dripping, making it difficult to work with.

[0006] Therefore, the present invention has been made in consideration of the above points, and an object of the present invention is to provide an aqueous paint stripper that does not contain benzyl alcohol and has excellent paint stripping properties and workability. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have discovered that by blending specific inorganic fine particles in a predetermined ratio, an aqueous paint stripper having excellent paint stripping properties and workability can be obtained. Based on this finding, the present invention has been completed.

[0008] Specifically, the paint film stripper of the present invention contains 30% by mass or more and 85% by mass or less of the following component (A), more than 2% by mass but 5% by mass or less of the following component (B), and 10% by mass or more of the following component (C), but is characterized by not containing benzyl alcohol: component (A): phenethyl alcohol or phenoxyethanol, component (B): organic bentonite or hydrophobic fumed silica, and component (C): water. By incorporating organic bentonite or hydrophobic fumed silica (component (B)) into an aqueous paint film stripper containing phenethyl alcohol or phenoxyethanol (component (A)) without benzyl alcohol as a solvent component, paint film stripping properties and workability can be improved. Specifically, the solvent components in the paint film stripper sufficiently penetrate the paint film, promoting softening of the paint film and facilitating paint film removal. Furthermore, dripping of the paint film stripper is suppressed, resulting in a paint film stripper with excellent workability.

[0009] The paint film remover of the present invention has a viscosity η3 (25°C) of 50 to 80 Pa·s at a rotation speed of 3 rpm measured with a Brookfield viscometer, and this viscosity η3 (25°C) is calculated by dividing the viscosity η of the paint film remover at a rotation speed of 30 rpm measured with a Brookfield viscometer by the viscosity η 30 (25℃) and the resulting TI value (η3 / η 30 ) is preferably adjusted to be 4 to 5.5. This further improves the paint film stripping properties and further suppresses dripping when applied, resulting in a paint film stripper that is easy to apply and does not drip easily.

[0010] In addition, in the paint film remover of the present invention, component (A) is preferably phenethyl alcohol, thereby allowing a component with excellent paint film remover properties to be selected as component (A) contained in the paint film remover of the present invention.

[0011] In addition, the paint film remover of the present invention preferably contains component (B) as organic bentonite, thereby enabling a component having excellent paint film remover properties and workability to be selected as component (B) contained in the paint film remover of the present invention.

[0012] In addition, in the paint film stripper of the present invention, the organic bentonite is preferably hydrogenated tallow alkonium bentonite, thereby allowing a material with particularly excellent paint film stripping properties and workability to be selected as the organic bentonite of component (B) contained in the paint film stripper of the present invention.

[0013] The paint remover of the present invention preferably further contains a polyhydric alcohol (Component (D)) and a cellulose derivative (Component (E)), which can enhance the emulsifying and dispersing properties of each of the blended components and improve the formulation stability.

[0014] In addition, the coating film peeling method of the present invention involves applying the above-mentioned coating film remover to a coating film provided on the surface of a substrate to soften the coating film and peel it from the substrate. By using the above-mentioned coating film remover, it is possible to reduce dripping and provide excellent workability, and to sufficiently soften the coating film so that it can be easily peeled from the surface of the substrate. [Effects of the Invention]

[0015] According to the present invention, a paint remover having the following excellent effects can be provided. (1) The paint remover penetrates the paint film sufficiently, promoting softening of the paint film and making it easy to remove. (2) It has excellent workability, such as being less likely to drip and being easy to apply. (3) It is a water-based paint remover that does not contain dichloromethane, N-methyl-2-pyrrolidone, or benzyl alcohol, so it reduces the risk of harm to health. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing the structure of a test piece prepared for a paint film peeling test using a paint film remover in an example and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0017] The paint film remover according to the present invention is described in detail below. The paint film remover according to the present invention comprises at least component (A): phenethyl alcohol or phenoxyethanol, component (B): organic bentonite or hydrophobic fumed silica, and component (C): water.

[0018] [Component (A): Phenethyl alcohol or phenoxyethanol] First, we will explain the component (A): phenethyl alcohol or phenoxyethanol contained in the paint film remover of the present invention. This component (A), phenethyl alcohol or phenoxyethanol, is incorporated as a solvent component that acts to soften (swell and moisten) the paint film formed on the surface of a substrate. More specifically, the phenethyl alcohol or phenoxyethanol incorporated in the paint film remover penetrates the paint film and dissolves the paint film in the phenethyl alcohol or phenoxyethanol, thereby moistening (swelling) and softening the paint film. The softened paint film has weaker adhesion to the substrate, such as steel, and can be easily removed using a scraper or the like.

[0019] Component (A) may contain either phenethyl alcohol or phenoxyethanol, or may contain both phenethyl alcohol and phenoxyethanol. Of these, phenethyl alcohol is preferably used in the paint film remover of the present invention from the viewpoint of excellent paint film remover properties. Since the paint film remover of the present invention does not contain benzyl alcohol as a solvent component, the risk of harm to health can be reduced.

[0020] The content of component (A) incorporated into the paint film remover of the present invention, i.e., the content of either phenethyl alcohol or phenoxyethanol, or the combination of phenethyl alcohol and phenoxyethanol, is preferably from 30 to 85% by mass, more preferably from 30 to 70% by mass, and particularly preferably from 35 to 60% by mass, based on the total amount of the paint film remover, from the viewpoint of ensuring safety as an aqueous paint film remover while exerting its paint film stripping effect.

[0021] [Component (B): organic bentonite or hydrophobic fumed silica] Next, we will explain the component (B): organic bentonite or hydrophobic fumed silica contained in the paint stripper of the present invention. The paint stripper of the present invention is prepared by mixing and dispersing or emulsifying the various components described above and below. If the viscosity of the paint stripper is too high, the solvent components in the paint stripper may not penetrate the paint film well, resulting in poor paint stripping properties. If the viscosity of the paint stripper is too low, the paint stripper may drip significantly after application, resulting in poor workability and paint stripping properties. Therefore, the organic bentonite or hydrophobic fumed silica of component (B) adjusts the viscosity of the paint stripper of the present invention and imparts thixotropy, improving the ease of spreading the paint stripper when applied and the leveling properties (surface uniformity after application) upon application. This enhances the penetration and stripping action of the above-mentioned component (A) into the paint film and improves workability, such as reducing dripping.

[0022] In the present invention, the organic bentonite of component (B) refers to an organic bentonite modified with quaternary ammonium cations, obtained by reacting the crystal surface of bentonite, a clay mineral whose main component is montmorillonite, with a quaternary ammonium cation. Commercially available organic bentonites that can be used in the present invention include, but are not limited to, Esben series products such as Esben (registered trademark), Esben NTO, Esben NZ, Esben NA70, and Esben NEZ, as well as Organite (registered trademark) (all products of Nippon Organic Clay Co., Ltd.), Kunibis-110 (product of Kunimine Industries Co., Ltd.), and Kunibis-127 (product of Kunimine Industries Co., Ltd.). Among these, the viscosity η3 (25°C) and viscosity η 30 (25℃) and TI value (η3 / η 30 ) can be set in a suitable range, and from the viewpoint of being able to improve paint film peelability, the Esben series products such as Esben, Esben NTO, Esben NZ, Esben NA70 and Esben NEZ, which are hydrogenated tallow alkonium bentonite, can be preferably used, and Esben NTO, which is hydrogenated tallow alkonium bentonite, can be particularly preferably used.

[0023] The hydrophobic fumed silica of component (B) is silica fine particles whose particle surfaces have been hydrophobized with hydrophobic functional groups. Although not particularly limited, commercially available hydrophobic fumed silica usable in the present invention includes AEROSIL (registered trademark) R974 and AEROSIL R972 (products of Nippon Aerosil Co., Ltd.), which are fumed silica whose silica surface has been hydrophobized with dimethyldichlorosilane.

[0024] Component (B) may contain either organic bentonite or hydrophobic fumed silica, or may contain both organic bentonite and hydrophobic fumed silica. Of these, organic bentonite is preferably used in the paint film stripper of the present invention from the viewpoint of excellent paint film stripping properties and workability.

[0025] The content of component (B) blended in the paint stripper of the present invention, i.e., the content of either organic bentonite or hydrophobic fumed silica, or the content of a combination of organic bentonite and hydrophobic fumed silica, is determined based on the viscosity η3 (25°C) and viscosity η 30 (25℃) and TI value (η3 / η 30 ) can be set within a suitable range, and from the viewpoint of improving both the coating film stripping action and resistance to dripping, the content is preferably more than 2% by mass and not more than 5% by mass, more preferably 2.5% by mass or more and 4% by mass or less, and particularly preferably 2.5% by mass or more and 3.5% by mass or less, based on the total amount of the coating film stripping agent.

[0026] [Component (C): Water] Component (C) water contained in the paint film remover of the present invention is a component used as a dispersion medium for the above-mentioned blended components and the blended components described below. The content of component (C) water is preferably 10% by mass or more based on the total amount of the paint film remover, and is not particularly limited, but is preferably 20% by mass to 70% by mass, more preferably 30% by mass to 60% by mass.

[0027] [Component (D): Polyhydric alcohol] Next, the polyhydric alcohol of component (D) that can be contained in the paint remover of the present invention will be described. The paint remover of the present invention may contain a polyhydric alcohol (D) that has the effect of increasing the compatibility of component (A) phenethyl alcohol or phenoxyethanol with component (C) water, thereby improving the stability of the paint remover as a single agent. As the polyhydric alcohol of component (D), glycols such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol are preferably used, and of these, ethylene glycol and propylene glycol are particularly preferred. The content of component (D) contained in the paint remover of the present invention is preferably 2 to 20% by mass, more preferably 3 to 15% by mass, and particularly preferably 4 to 10% by mass, based on the total amount of the paint remover.

[0028] [Component (E): Cellulose derivative] Next, the cellulose derivative of component (E) that can be contained in the paint film remover of the present invention will be described. The paint film remover of the present invention may contain a cellulose derivative (E) that has an emulsifying and thickening effect in order to improve the workability of the paint film remover, such as reducing dripping, and to stabilize the emulsified and dispersed state of the formulation. The organic bentonite or hydrophobic fumed silica of component (B) described above also has the effect of adjusting the viscosity of the paint film remover, but by combining it with the cellulose derivative of component (E), it is possible to adjust the paint film remover to a state that is easier to handle and to easily improve the formulation stability.

[0029] In the present invention, any material can be used as the cellulose derivative of component (E) as long as it is a component that mainly has an emulsifying and thickening action, and examples thereof include hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, etc. The content of component (E) incorporated into the paint film remover of the present invention is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and particularly preferably 0.1 to 1.5% by mass, based on the total amount of the paint film remover.

[0030] [Component (F): Evaporation inhibitor] Next, the evaporation inhibitor of component (F) that can be contained in the paint film stripper of the present invention will be described. The paint film stripper of the present invention preferably contains an evaporation inhibitor of component (F) to prevent evaporation or volatilization of component (A), which is the solvent component, and water (component (C)), which is the dispersion medium, contained in the paint film stripper. In the present invention, the evaporation inhibitor of component (F) is a component that can suppress evaporation or volatilization of phenethyl alcohol or phenoxyethanol, which is component (A), and water, which is component (C). Specific examples of the evaporation inhibitor of component (F) include hydrocarbons, esters, vegetable oils and fats, higher fatty acids, higher alcohols, waxes, and silicone oils, and one or more of these can be used in combination.

[0031] Examples of hydrocarbons in the evaporation inhibitor (component (F)) of the present invention include paraffin wax, liquid paraffin, petrolatum, squalane, and squalene. Examples of esters include dimer acid esters, oligomeric sterol esters, isopropyl myristate, and caprylic / capric triglyceride. Examples of vegetable oils include jojoba oil, shea butter, coconut oil, palm oil, hydrogenated castor oil, corn oil, olive oil, rapeseed oil, sesame oil, cottonseed oil, and soybean oil. Examples of higher fatty acids include oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, linoleic acid, and linolenic acid. Examples of higher alcohols include lauryl alcohol, stearyl alcohol, cetyl alcohol, oleyl alcohol, lanolin alcohol, cholesterol, phytosterols, hexyldodecanol, and isostearyl alcohol. Examples of waxes include cotton wax, beeswax, candelilla wax, carnauba wax, bayberry wax, and libota wax. Examples of silicone oils include methyl trimethicone, dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and cyclopentasiloxane. The content of component (F) incorporated into the paint stripper according to the present invention is preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, and particularly preferably 0.2 to 3% by mass, based on the total amount of the paint stripper.

[0032] The coating remover of the present invention may contain a surfactant and / or solvent to enhance the dispersibility of the above-mentioned blended components and improve formulation stability. The surfactant may be any surfactant capable of emulsifying and dispersing the above-mentioned blended components, but nonionic surfactants are preferably selected from the viewpoint of excellent emulsifying power. Suitable nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene glycol fatty acid esters, and combinations thereof. Suitable solvents include aromatic hydrocarbons such as alkylbenzenes, and alkylcyclohexanes such as methylcyclohexane.

[0033] The paint remover of the present invention may contain, in addition to the above-mentioned components, other components that can be added to ordinary paint removers, so long as the effects of the present invention are not impaired. Such other components include a pH adjuster, a colorant, an emulsion stabilizer, etc.

[0034] [Physical properties of paint remover (viscosity)] The paint film remover of the present invention is a single-agent formulation obtained by mixing and dispersing or emulsifying the above-mentioned components, and is in the form of a thick paste. Here, if the viscosity of the paint film remover is too high, the solvent components in the paint film remover will not penetrate the paint film well, potentially resulting in poor paint film remover properties. On the other hand, if the viscosity of the paint film remover is too low, significant dripping after application will occur, potentially resulting in poor workability and paint film remover properties. Therefore, from the viewpoint of excellent paint film remover properties and workability, the viscosity η3 (25°C) of the paint film remover measured at a rotation speed of 3 rpm using a Brookfield viscometer is preferably 35 to 100 Pa·s, more preferably 50 to 90 Pa·s, and particularly preferably 50 to 80 Pa·s. Furthermore, the viscosity η3 (25°C) at a rotation speed of 30 rpm using a Brookfield viscometer is preferably 35 to 100 Pa·s, more preferably 50 to 90 Pa·s, and particularly preferably 50 to 80 Pa·s. Furthermore, the viscosity η3 (25°C) of the paint film remover measured at a rotation speed of 30 rpm using a Brookfield viscometer is preferably 35 to 100 Pa·s, more preferably 50 to 90 Pa·s, and particularly preferably 50 to 80 Pa·s. 30The viscosity η3(25°C) at a rotation speed of 3 rpm measured by a Brookfield viscometer is preferably 5 to 20 Pa·s, more preferably 10 to 20 Pa·s, and particularly preferably 12 to 16 Pa·s. The viscosity η3(25°C) at a rotation speed of 3 rpm measured by a Brookfield viscometer is then calculated as the viscosity η 30 (25℃) and the resulting TI value (η3 / η 30 ) is preferably 3 to 11, more preferably 4 to 8, and particularly preferably 4 to 5.5. 30 (25℃) and TI value (η3 / η 30 ) within the above range, a paint stripper having excellent paint stripping properties and workability can be obtained.

[0035] The paint remover of the present invention can be produced by a known method for producing a paint remover, such as by weighing out predetermined amounts of components (A) to (C) and other components such as components (E) and (F), mixing the components, and stirring them with a mixer or the like to emulsify, disperse, and homogenize them.

[0036] The method of use of the coating film remover of the present invention is not particularly limited, but for example, the coating film remover is used by applying the coating film formed on the surface of a substrate and leaving it for a predetermined period of time. The leaving time can be adjusted depending on conditions such as temperature, humidity, and coating thickness. During leaving, the solvent component (A) in the coating film remover penetrates into the coating film, softening it (swelling and wetting), and the softened coating film after leaving can be easily peeled and removed from the substrate with a scraper or the like. The coating film remover of the present invention has good penetration of the solvent component in the coating film into the coating film, excellent coating film peeling properties, viscosity properties that make it easy to spread, and resistance to dripping after application, resulting in excellent workability. [Example]

[0037] The present invention will be described in detail below using examples and comparative examples. The methods for measuring the physical properties of the paint remover and the methods for evaluating the effects in the following examples and comparative examples are as follows.

[0038] (1) Viscosity η (25℃) Using a Brookfield viscometer (model number: TVB-10M, manufactured by Toki Sangyo Co., Ltd.) and a TM rotor (model number: TM4, manufactured by Toki Sangyo Co., Ltd.) as the spindle, the viscosity η3 was measured at a rotation speed of 3 rpm and a temperature of 25°C. Also, using the same viscometer and a TM rotor (model number: TM4, manufactured by Toki Sangyo Co., Ltd.) as the spindle, the viscosity η3 was measured at a rotation speed of 30 rpm and a temperature of 25°C. 30 was measured.

[0039] (2) TI value (thixotropy coefficient) Based on the viscosity measured in (1) above, the TI value = (viscosity η3) / (viscosity η 30 The TI value was calculated using the formula:

[0040] (3) Emulsification dispersibility 100 mL of each of the paint removers prepared in the Examples and Comparative Examples was placed in a 100 mL colorless, transparent glass container, the container was covered, and the container was left to stand at 20°C for 24 hours. After 24 hours, the container lid was opened, and the state of the paint remover was visually observed from above the opening and through the outer periphery of the container. Cases where no separation was observed and the emulsified dispersion state was maintained were evaluated as "Good," and cases where separation was observed and the emulsion dispersion was not achieved were evaluated as "Poor."

[0041] (4) Coating properties (less dripping) Ten grams of each paint release agent prepared in the Examples and Comparative Examples was applied to a general-purpose structural rolled steel sheet (SS400) in a rectangular pattern measuring 80 mm long and 100 mm wide using an applicator to a thickness of 1,000 μm. After application, the steel sheet was placed vertically (90°) and allowed to stand for 30 minutes. After 30 minutes, the vertical distance to the point where the paint release agent had flowed beyond the previously applied rectangular area was measured and recorded as the measured sagging value (cm) after application. A measured sagging value of 0 cm (no sagging) was evaluated as excellent (◎); a measured sagging value of more than 0 cm but not more than 3 cm was evaluated as good (○); a measured sagging value of more than 3 cm but not more than 7 cm was evaluated as acceptable (△); and a measured sagging value of more than 7 cm was evaluated as poor (×).

[0042] (5) Peelability First, test pieces for the peelability test were prepared as follows. The test pieces were prepared in accordance with the A-5 series coating specifications for new construction described in the Steel Highway Bridge Corrosion Prevention Handbook. A flat plate (0.3 mm × 210 mm × 300 mm) of general structural rolled steel (SS400) was used as the substrate. After applying an etching primer, four types of paint (II) to (V) described below were applied sequentially as shown in Figure 1 twice, until a total of eight layers of paint were applied to a target total thickness of 390 μm. After painting, the test pieces were left in an incubator at 60°C for 40 hours to accelerate deterioration and prepare the test pieces. The total thickness was 432 μm (average value). The paints used and the target thicknesses of each paint layer are as follows: (I) Etching primer: Long-lasting etching primer (JIS K 5633:2002 Etching primer type 2), Metalact H15 (Kansai Paint Co., Ltd.), target film thickness 15 μm (II) Lead- and chromium-free rust-preventive paint (gray color) (JIS K5674:2008 Lead- and chromium-free rust-preventive paint type 1), Rasgon Safety Gray (Kansai Paint Co., Ltd.), target film thickness 35 μm (III) Lead- and chromium-free rust-preventive paint (rust red color) (JIS K 5674:2008 Lead- and chromium-free rust-preventive paint type 1), Rasgon Safety Rust Red Color (Kansai Paint Co., Ltd.), target film thickness 35 μm (IV) Long-oil phthalic acid resin paint intermediate coat (white) (JIS K 5516:2003 Synthetic resin blend paint type 2 intermediate coat), SD Marine Safety Intermediate Coat White (Kansai Paint Co., Ltd.), target film thickness 30 μm (V) Long-oil phthalic acid resin paint topcoat (yellow) (JIS K 5516:2003 Synthetic resin blend paint type 2 for topcoats), SD Marine Safety Topcoat Yellow (Kansai Paint Co., Ltd.), target film thickness 30 μm

[0043] The test was conducted in accordance with "4. Testing of Paint Strippers" in the revised second edition of the Guidelines for Paint Strippers for Civil Steel Structures (draft), Appendix: Quality Standards for Paint Strippers for Civil Steel Structures and Paint Removal Methods Using Them (provisional draft). Specifically, 2 g of each paint stripper prepared in the Examples and Comparative Examples was taken and applied to a 4.5 cm square section on the test piece prepared as described above (application amount: 1 kg / m 2 (Assuming the case where the coating layer was peeled off). After application, the sample was left to stand flat for 24 hours. After 24 hours, the coating film softened by the coating remover was removed with a scraper, and the number of coating layers that could be peeled off was visually confirmed. If the number of coating layers that could be peeled off was 8, the sample was rated as excellent (◎); if the number of coating layers that could be peeled off was 6 to 7, the sample was rated as good (○); if the number of coating layers that could be peeled off was 4 to 5, the sample was rated as fair (△); and if the number of coating layers that could be peeled off was 3 or less, the sample was rated as poor (×).

[0044] Table 1 also shows the specifications of component (B), component (D), component (E), component (F) and other components among the components of the paint remover prepared in the following examples and comparative examples.

[0045] [Table 1]

[0046] [Example 1] In this example, the paint remover of Example 1 shown in Table 2 below was prepared. The components shown in Tables 1 and 2 were mixed and stirred to obtain the paint remover of Example 1. When adding the evaporation inhibitor of component (F), component (F) was first dissolved and emulsified in the other components, the solvent and surfactant, and then added and mixed. The paint remover of Example 1 thus obtained was subjected to measurement of physical properties and evaluation of effects based on the measurement and evaluation methods (1) to (5) described above. The results are shown in Table 2 below.

[0047] [Example 2] to [Example 10] As in Example 1, the components shown in Tables 1 and 2 were mixed and stirred to obtain the paint film removers of Examples 2 to 10. The paint film removers of Examples 2 to 10 thus obtained were subjected to measurement of physical properties and evaluation of effects based on the above-mentioned measurement and evaluation methods (1) to (5). The results are shown in Table 2 below.

[0048] [Table 2]

[0049] [Comparative Example 1] to [Comparative Example 6] As in Example 1, the components shown in Tables 1 and 3 were mixed and stirred to obtain the coating removers of Comparative Examples 1 to 6. The coating removers of Comparative Examples 1 to 6 thus obtained were subjected to measurement of physical properties and evaluation of effects based on the above-mentioned measurement and evaluation methods (1) to (5). The results are shown in Table 3 below.

[0050] [Table 3]

[0051] [Comparative Example 7] to [Comparative Example 14] As in Example 1, the components shown in Tables 1 and 4 were mixed and stirred to obtain the coating removers of Comparative Examples 7 to 14. The coating removers of Comparative Examples 7 to 14 thus obtained were subjected to measurement of physical properties and evaluation of effects based on the measurement and evaluation methods (1) to (5) described above. The results are shown in Table 4 below. The coating removers prepared in Comparative Examples 9 to 11 and Comparative Examples 13 and 14 had poor emulsifying and dispersing properties, and separated into two layers, preventing the production of homogeneous compositions. Therefore, of the measurement and evaluation methods described above, measurement and evaluation other than that of emulsifying and dispersing properties in (3) were not performed.

[0052] [Table 4]

[0053] The results of Examples 1 to 8 and 10 in Table 2 indicate that a paint remover with excellent application properties (resistance to dripping) can be obtained by incorporating 2.5 to 5 mass% of organic bentonite as component (B). In contrast, the results of Comparative Examples 1 to 3 in Table 3 indicate that when no organic bentonite was incorporated as component (B) or when it was incorporated at 2 mass% or less, application properties (resistance to dripping) were poor. Furthermore, the results of Comparative Examples 7 to 14 in Table 4 indicate that when various types of inorganic fine particles other than organic bentonite were incorporated as component (B), not only was application properties (resistance to dripping) not improved (Comparative Examples 7, 8, and 9), but the compound was not even able to be formulated into a single-component formulation because it did not emulsify and disperse (Comparative Examples 9 to 11, 13, and 14).

[0054] Furthermore, according to the results of Examples 1 to 4 in Table 2, while blending organic bentonite as component (B) in the range of 2.5 to 5 mass%, the viscosity η3 (25°C) of the paint remover was increased to 50 to 80 Pa·s and the TI value (η3 / η 30 It was found that by adjusting the η3 (25°C) to 4 to 5.5, the paint film stripping properties were also excellent. 30 It was found that by blending the organic bentonite of component (B) so that the viscosity (η3) of the paint stripper is 4 to 5.5, a paint stripper that is excellent in both paint stripping properties and application properties (resistance to dripping) can be obtained. Furthermore, it was found that by using hydrogenated tallow alkonium bentonite (organic bentonite B1) as the organic bentonite of component (B), it becomes easy to adjust the viscosity η3 (25°C) and TI value of the paint stripper to fall within the specified range, making it suitable as a blending component for the paint stripper of the present invention.

[0055] On the other hand, the results of Example 9 in Table 2 show that by incorporating hydrophobic fumed silica as component (B), a paint remover can be obtained that not only has excellent coating properties (resistance to dripping) but also excellent paint film peeling properties. In contrast, the results of Comparative Example 9 in Table 4 show that when hydrophilic fumed silica is incorporated as component (B), it is not possible to emulsify and disperse it, making it impossible to form a single-component paint. Furthermore, the results of Example 9 in Table 2 show that the viscosity η3 (25°C) of the paint remover was 50 to 80 Pa·s, and the TI value (η3 / η 30 ) was also in the range of 4 to 5.5. From these results, it can be seen that even when hydrophobic fumed silica is used as component (B), the viscosity η3 (25°C) of the paint remover is 50 to 80 Pa·s and the TI value (η3 / η 30 It was found that by adjusting the ratio of the viscosity of the coating to the viscosity of the resin to be 4 to 5.5, a coating remover excellent in both coating remover properties and coating adhesion (resistance to dripping) can be obtained.

[0056] The present invention is not limited to the above-described embodiments, and various modified design forms are included within the technical scope as long as they do not deviate from the gist of the invention described in the claims. [Industrial Applicability]

[0057] The paint film remover of the present invention is excellent in safety, paint film stripping properties, and workability, and is used to safely and efficiently remove paint applied to steel structures, buildings, etc.

Claims

1. A paint film remover characterized by containing 30% by mass or more and 85% by mass or less of the following component (A), more than 2% by mass and 5% by mass or less of the following component (B), and 10% by mass or more of the following component (C), and not containing benzyl alcohol. Component (A): Phenethyl alcohol or phenoxyethanol Component (B): Organic bentonite or hydrophobic fumed silica Component (C): water

2. Viscosity η of the paint remover measured with a Brookfield viscometer at a rotation speed of 3 rpm ３ (25°C) is 50 to 80 Pa s, The viscosity η ３ (25°C) is the viscosity η of the paint remover measured by a Brookfield viscometer at a rotation speed of 30 rpm. ３０ (25 ° C.) ３ / η ３０ 2. The paint remover according to claim 1, wherein the saturation coefficient (σ) is 4 to 5.

5.

3. 2. The paint stripper according to claim 1, wherein the component (A) is phenethyl alcohol.

4. 2. The paint stripper according to claim 1, wherein the component (B) is an organic bentonite.

5. 5. The paint stripper according to claim 4, wherein the organic bentonite is hydrogenated tallow alkonium bentonite.

6. 2. The paint stripper according to claim 1, further comprising a component (D): a polyhydric alcohol and a component (E): a cellulose derivative.

7. A method for removing a coating film, comprising applying the coating film remover according to any one of claims 1 to 6 to a coating film provided on the surface of a substrate to soften the coating film, and then removing the coating film from the substrate.

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