Methods for removing contaminants

Abstract

To provide a method for removing pollutants that uses a self-detaching film forming composition, which is applied onto a target surface and then allows its coating to peel off spontaneously only by drying, so that the work of removal of pollutants and the work of peeling and recovery of the coating having adsorbed the pollutants can be performed easily in a short time.SOLUTION: A method for removing pollutants attached to a target surface, comprises the steps of: forming a coating by applying a self-detaching film forming composition containing components (A)-(C), onto the target surface having pollutants attached thereto; drying the coating; and removing the pollutants together with the coating, caused by the self-detachment of the coating with drying. (A): Film-forming component. (B): Volatile solvent. (C) Silicone compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for removing contaminants using a self-peeling film that spontaneously peels off after being applied to a target surface and drying. [Background technology]

[0002] Generally, methods for removing dirt, fine particles, and other dust adhering to or remaining on equipment surfaces include washing with water or solvents, wiping, scraping with mechanical force, and vacuuming. However, these operations carry the risk of workers inhaling cleaning solutions or scattered dust. In particular, if the cleaning solution used is harmful to the human body, or if the substance to be removed is a contaminant containing asbestos, hazardous chemicals, or radioactive materials, measures are needed to prevent workers from inhaling the cleaning solution or contaminants. For example, since contaminants at nuclear power plants contain radioactive materials, there is a risk of exposure to radiation through inhalation or contact with these materials for workers during cleaning and decommissioning work. Therefore, there is a need for technologies that can remove such contaminants efficiently and safely.

[0003] Contaminants tend to remain on equipment surfaces, especially in fine details such as uneven surfaces. One effective technique for removing such contaminants without scattering them is to use a release-type coating, which involves applying a coating to the target surface, drying it, and then peeling off the coating to remove the adsorbed contaminants. While this technique is effective for removing contaminants remaining in fine details, it is difficult to create a starting point for peeling at the edges of the coating after drying. If this process takes a long time, the risk of workers inhaling or being exposed to harmful substances increases. Furthermore, in environments where people cannot enter, it is difficult to recover the peeled coating.

[0004] To address these problems, if a self-peeling film that spontaneously peels off after drying can be developed, the recovery process could be carried out easily and quickly, and remote work by robots or other means would also become possible.

[0005] Regarding technologies related to self-peeling films, Patent Document 1 discloses a self-peeling penetrant developer removal material obtained by dissolving a cellulose-based synthetic resin having the ability to form a peelable resin film in a volatile organic solvent. Patent Document 2 discloses a method for peeling off a film mainly composed of an aqueous paint and containing a water-soluble thickener by swelling it with water. On the other hand, Patent Document 3 discloses a technology different from self-peeling films, in which a coating composition is applied to a substrate in advance to form a barrier coating, and after contaminants have accumulated on the barrier coating, the barrier coating and contaminants are removed from the substrate. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 59-171841 [Patent Document 2] Japanese Patent Publication No. 2000-327958 [Patent Document 3] Special Publication No. 2010-530806 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The technology described in Patent Document 1 contains a considerable amount of organic solvent, which raises concerns about the generation of an unpleasant odor, potential health hazards to workers, and damage to the surfaces of surrounding equipment. Furthermore, it has the problem of insufficient self-peelability. The method described in Patent Document 2 requires the addition of water to the film to cause swelling, which presents problems in terms of labor and risks to workers. Moreover, the method described in Patent Document 3 involves removing the barrier coating and contaminants by washing or wiping, making the method of removing the coating film inconvenient.

[0008] Therefore, the present invention relates to a method for removing contaminants, which enables the removal of contaminants and the peeling and recovery of a coating film that has adsorbed contaminants to be easily and quickly performed by using a self-peeling film-forming composition that spontaneously peels off the coating film simply by drying after being applied to the target surface. [Means for Solving the Problems]

[0009] The inventors of the present invention have found that by utilizing the self - peeling property of a composition containing a film - forming component and a silicone compound in a volatile solvent, it becomes possible to remove the contaminants that satisfy the above requirements, and thus completed the present invention.

[0010] The present invention provides a method for removing contaminants adhering to a target surface, comprising the steps of: applying a composition for forming a self - peeling film containing components (A) to (C) to the target surface to which the contaminants adhere to form a coating film; drying the coating film; and removing the contaminants together with the coating film by self - peeling of the coating film accompanying the drying. (A) Film - forming component (B) Volatile solvent (C) Silicone compound

[0011] Furthermore, the present invention provides the use of a composition containing the following components (A) to (C) for removing contaminants on a target surface by self - peeling accompanying the drying of a coating film. (A) Film - forming component (B) Volatile solvent (C) Silicone compound

[0012] Furthermore, the present invention provides a composition for forming a self - peeling film, which contains the following components (A) to (C) and in which the mass ratio (C) / (A) of component (C) to component (A) is 0.01 or more and 1.00 or less. (A) Film - forming component (B) Volatile solvent (C) Silicone compound

[0013] Furthermore, the present invention provides a composition for forming a self - peeling film, which contains the following components (A) to (C) and in which the degree of peeling measured by the following evaluation method is 20% or more and 100% or less. (A) Film - forming component (B) Volatile solvent (C) Silicone compound <Evaluation method> Apply the composition to an epoxy resin-coated substrate at 0.3 g / cm 2 and dry for 24 hours. Measure the adhesion area S1 between the composition spread on the substrate before drying and the substrate, and the area S2 where the dried coating film contacts the substrate. The value of (S1 - S2) / S1 calculated is defined as the degree of peeling.

Advantages of the Invention

[0014] The method for removing contaminants of the present invention can easily and quickly perform the removal of contaminants and the peeling and recovery operation of the coating film adsorbed with contaminants by using a composition for forming a self-peeling film that spontaneously peels off the coating film only by drying after being applied to the target surface.

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram showing the mechanism of self-peeling in the method for removing contaminants of the present invention.

Embodiments for Carrying Out the Invention

[0016] In the present invention, self-peeling means that the degree of peeling of the dried coating film measured by the following evaluation method is 20% or more and 100% or less. This degree of peeling is preferably 30% or more and 100% or less, more preferably 40% or more and 100% or less, more preferably 50% or more and 100% or less, more preferably 60% or more and 100% or less, more preferably 70% or more and 100% or less. <Evaluation method> Apply the composition to an epoxy resin-coated substrate at 0.3 g / cm 2 and dry for 24 hours. Measure the adhesion area S1 between the composition spread on the substrate before drying and the substrate, and the area S2 where the dried coating film contacts the substrate, and define the value of (S1 - S2) / S1 calculated as the degree of peeling.

[0017] 〔Component (A): Film-forming component〕 The film-forming component of component (A) is dissolved or dispersed in the self-peelable film-forming composition of the present invention and generally includes substances called film-forming agents, paints, and aqueous thickeners. Component (A) exhibits self-peelability due to internal stress during drying, and its glass transition temperature is preferably 0°C or higher, more preferably 10°C or higher, even more preferably 20°C or higher, and even more preferably 30°C or higher. Furthermore, from the viewpoint of improving film strength, it is preferably a polymer with a glass transition temperature of 300°C or lower, more preferably 280°C or lower, even more preferably 260°C or lower, and even more preferably 240°C or lower. Component (A) is preferably a component other than component (C) described later, and is preferably one or more polymers selected from polyvinyl alcohol, copolymers with vinyl alcohol as the main structure, cellulose ether, polystyrene sulfonic acid or its salts, acrylic resin, xanthan gum, gellan gum, and guar gum.

[0018] Furthermore, the weight-average molecular weight of the film-forming component of component (A) is preferably 5000 or more, more preferably 7000 or more, and even more preferably 10000 or more, from the viewpoint of improving the formation of the coating film and the self-peeling of the dried coating film, and from the viewpoint of improving the coatability, it is preferably 10,000,000 or less, more preferably 5,000,000 or less, and even more preferably 2,000,000 or less.

[0019] As polyvinyl alcohol, commercially available products such as Kuraray Poval 3-98, 5-98, 28-98, 60-98, 27-95, 27-96, 17-94, 7-92, 3-88, 5-88, 22-88, 44-88, 95-88, and 48-80 (manufactured by Kuraray Co., Ltd.) can be used. As polystyrene sulfonic acid or its salts, commercially available products such as PS-100 (manufactured by Tosoh Finechem Co., Ltd.) can be used. Copolymers with vinyl alcohol as the main structure include vinyl alcohol-ethylene copolymers and hydrolysates of vinyl acetate-ethylene copolymers. Commercially available hydrolysates of vinyl acetate-ethylene copolymers include Exceval RS2117, RS-2817, RS-1713, RS-1717, AQ-4104, and HR-3010 (manufactured by Kuraray Co., Ltd.) can be used.

[0020] Examples of cellulose ethers include carboxymethylcellulose or its salts, and hydroxypropylmethylcellulose. Commercially available carboxymethylcellulose or its salts include Sunrose APP-84 (manufactured by Nippon Paper Industries Co., Ltd.), and commercially available hydroxypropylmethylcellulose includes Metroze 60SH-15 and 60SH-03 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0021] As acrylic resins, methacrylic acid / methyl methacrylate copolymers, methyl acrylate / methyl methacrylate / methacrylic acid polymers, octyl acrylate / alkyl acrylate copolymers (e.g., DERMACRYL 79, manufactured by Nouryon), methacrylic acid / alkyl methacrylate / dimethylpolysiloxane block copolymers (e.g., Myblock Wako 101, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), methacrylic acid / 1,1-dimethylethyl acrylate / ethyl acrylate copolymers (e.g., Luvimer 100P, manufactured by BASF SE) can be used.

[0022] Of component (A), polyvinyl alcohol and copolymers mainly composed of vinyl alcohol are preferred because they have high film strength after drying, resulting in good workability when removing the film from the target surface. On the other hand, cellulose ether, polystyrene sulfonic acid or its salts, acrylic resin, xanthan gum, gellan gum, and guar gum are preferred because they have excellent self-peelability.

[0023] The content of component (A) in the self-peeling film-forming composition of the present invention is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 9% by mass or more, from the viewpoint of sufficiently exhibiting the self-peeling properties of the dried coating film, and from the viewpoint of improving the coatability, it is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0024] Furthermore, when the target surface is a material with fine irregularities such as cement solidified material or concrete, in order to exhibit sufficient film strength and self-peelability, the content of component (A) in the self-peelable film-forming composition of the present invention is preferably 14% by mass or more, more preferably 19% by mass or more, and also preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0025] [Component (B): Volatile solvent] The volatile solvent in component (B) is a substance that is volatile in a liquid state and is selected from water and volatile organic solvents. It is preferable that it contains water, and even more preferable that it is mainly water. Furthermore, from the viewpoint of drying after application to form a suitable dry coating film, a volatile organic solvent can be used in combination with water. Examples of volatile organic solvents include alcohols such as ethanol, methanol, and propanol, ketones such as acetone, and tetrahydrofuran, and it is preferable that one or more are selected from alcohols and ketones. Furthermore, the vapor pressure of the volatile organic solvent is preferably 0.01 kPa or more and 106.66 kPa or less at 20°C, more preferably 0.13 kPa or more and 66.66 kPa or less, even more preferably 0.67 kPa or more and 40.00 kPa or less, and even more preferably 1.33 kPa or more and 40.00 kPa or less. When component (B) contains a volatile organic solvent, its proportion is preferably 20% by mass or less of the total component (B), more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0026] The content of component (B) in the self-peelable film-forming composition of the present invention is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more, from the viewpoint of improving the applicability to the target surface, and preferably 92% by mass or less, more preferably 90% by mass or less, even more preferably 80% by mass or less, and even more preferably 70% by mass or less, from the viewpoint of improving self-peelability.

[0027] [Component (C): Silicone compound] The silicone compound of component (C) is dissolved or dispersed in the self-peelable film-forming composition of the present invention and has the function of bleeding out from the coating film as the coating film dries, thereby reducing the adhesion to the target surface. The silicone compound has a kinematic viscosity of 6 mm. 2 Examples include non-volatile dimethylpolysiloxanes with a viscosity of 1 / s or more, polyether-modified silicones, amino-modified silicones, polyglycerol-modified silicones, and N-propionylethyleneimine-dimethylsiloxane copolymers.

[0028] The content of component (C) in the self-peelable film-forming composition of the present invention is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, from the viewpoint of improving the self-peelability of the dried coating film, and from the viewpoint of dispersion or dissolution stability, it is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and even more preferably 7% by mass or less.

[0029] Furthermore, the mass ratio (C) / (A) of component (C) to component (A) is preferably 0.01 or higher, more preferably 0.05 or higher, even more preferably 0.07 or higher, and also preferably 1.00 or lower, more preferably 0.7 or lower, and even more preferably 0.5 or lower, from the viewpoint of sufficiently exhibiting the self-peelability of the dried coating film.

[0030] [Optional ingredients] The self-peeling film-forming composition of the present invention may further contain components such as surfactants, thickeners, and plasticizers, to the extent that they do not impair the self-peelability of the dried coating film.

[0031] Any of the following surfactants can be used: anionic surfactants, cationic surfactants, nonionic surfactants, or amphoteric surfactants.

[0032] As a thickening agent, components other than component (A) of the present invention, such as inorganic thickening agents like bentonite, aluminum magnesium silicate, laponite, hectorite, and anhydrous silicic acid, may be used at a low concentration such that they do not form a film on their own. Examples of plasticizers include propylene glycol, 1,3-butylene glycol, glycerin, isopentylene glycol, hexylene glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol.

[0033] Furthermore, the self-peeling film-forming composition of the present invention may be a concentrated product in which the content of component (B) is reduced due to transportation or other circumstances. In that case, it is used after diluting with component (B) so that the content of components (A) to (C) falls within the preferred range described above.

[0034] [Methods for removing contaminants] The present invention provides a method for removing contaminants, comprising the steps of: applying a self-peeling film-forming composition containing components (A) to (C) to a target surface to which contaminants are attached to form a coating film; drying the coating film; and removing the contaminants together with the coating film by the self-peeling of the coating film during the drying process.

[0035] In this invention, after applying the self-peeling film-forming composition of the present invention to a target surface to which contaminants are attached, the contaminants are adsorbed onto the dried coating during the drying process of the composition. As a result, the dried coating with the adsorbed contaminants spontaneously peels off from the target surface as it dries. At this time, the coating of the self-peeling film-forming composition of the present invention gradually peels off from the periphery of the coating as it dries. Subsequently, the contaminants on the target surface can be removed by collecting the peeled dried coating.

[0036] The target surfaces for removing contaminants include the surfaces of synthetic resins (such as epoxy resins, vinyl chlorides, acrylic resins, etc.), the painted surfaces of synthetic resins, metal surfaces, glass surfaces, ceramic surfaces, and the surfaces of cement solidified bodies, and the surfaces may be smooth or have fine irregularities. The fine irregularities can be applied within a range that does not inhibit self - peeling of surfaces such as the cement surface. The said target surfaces may be installed on the floor surfaces, wall surfaces, ceiling surfaces of various facilities such as power plants, factories, warehouses, office buildings, condominiums, parking lots, roads, bridges, tunnels, etc., or other inclined places such as slopes. Also, as the contaminants to be removed, it is possible to deal with powdery or granular deposits (for example, dust such as asbestos, dust, sand, sludge, mud, soot), oily deposits (for example, oily stains such as crude oil, tar, paints such as oil - based pens, lacquer sprays), deposits derived from animals and plants (moss, algae, bird droppings, dead insects, etc.), salts, etc. The technology of the present invention can also be used for removing contaminants in nuclear power plants, removing asbestos and other harmful substances, and working in a bad environment in addition to the contaminants in nuclear power plants.

[0037] As the method of applying to the target surface, for example, methods of directly spreading by using a spatula, a ground rake, a rake, a brush, a roller, etc., methods of spraying by using a spray, etc. can be mentioned. The application amount of the composition for forming a self - peeling film of the present invention to the target surface is preferably 0.1 kg / m from the viewpoint of enhancing the self - peeling property of the dry coating film. 2 More preferably, it is 1 kg / m or more. 2 Even more preferably, it is 2 kg / m or more. 2 Furthermore, from the viewpoints of easy curing and film formation, it is preferably 20 kg / m or less. 2 More preferably, it is 15 kg / m or less. 2 Even more preferably, it is 10 kg / m or less. 2 That is, it is as follows.

[0038] The drying process of the coating film after applying the composition to the target surface may be carried out by natural drying, air drying, or by using a heat source such as a halogen heater. The ambient temperature during the drying process is preferably -10°C or higher, more preferably 0°C or higher, even more preferably 5°C or higher, and also preferably 60°C or lower, more preferably 55°C or lower, and even more preferably 50°C or lower.

[0039] In the method for removing contaminants of the present invention, from the viewpoint of avoiding inhibition of self-peeling, it is preferable that the process up to the start of self-peeling does not include a step of applying or coating water, or an aqueous composition containing 50% by mass or more of water other than the self-peeling film-forming composition of the present invention. Furthermore, it is even more preferable to perform a drying step of the coating film immediately after the application step of the self-peeling film-forming composition of the present invention, without any other steps in between.

[0040] Figure 1 shows the mechanism of self-peeling by the contaminant removal method of the present invention. After applying the self-peeling film-forming composition of the present invention to a target surface, the coating film begins to shrink as the volatile solvent (water) of component (B) evaporates. However, while in a high-moisture state, the molecular chains of the film-forming component (A) can move freely, and no internal stress is generated. As drying progresses and the moisture content decreases, the coating film shrinks further, and the thermal motion of the molecular chains of component (A) is frozen. This generates internal stress, and it is presumed that the silicone compound (C) of component bleeds out of the coating film, forming a layer between it and the adherend (target surface). At this time, the stress is concentrated at the edges of the coating film, and because the adhesion strength of the coating film to the target surface is reduced due to the bleed-out component (C), it is thought that it becomes easier for the coating film to spontaneously peel off from the edges.

[0041] With respect to the embodiments described above, preferred embodiments of the present invention are further disclosed below.

[0042] <1> A method for removing contaminants adhering to a target surface, comprising the steps of: applying a self-peeling film-forming composition containing components (A) to (C) to the target surface to which the contaminants are adhering to form a coating film; drying the coating film; and removing the contaminants together with the coating film by the self-peeling of the coating film during drying. (A) Membrane-forming component (B) Volatile solvents (C) Silicone compound

[0043] <2> Preferably, the self-peeling film-forming composition is applied to the target surface using a rake, brush, roller, or sprayer. <1> The method for removing contaminants described below.

[0044] <3> The amount of self-peeling composition applied to the target surface is preferably 0.1 kg / m². 2 Above, a comfortable 1 kg / m 2 More preferably 2 kg / m 2 The above is true, and preferably 20 kg / m³ 2 For the following, a more preferable rate is 15 kg / m 2 More preferably 10 kg / m 2 The following is: <1> or <2> The method for removing contaminants described below.

[0045] <4> Preferably, after the step of applying the self-peeling film-forming composition to the target surface to form a coating film, the step of drying the coating film is performed without any other steps. <1> ~ <3> A method for removing contaminants as described in any one of the items.

[0046] <5> The drying process is preferably carried out in an environment at -10°C or higher, more preferably at 0°C or higher, even more preferably at 5°C or higher, and preferably at 60°C or lower, more preferably at 55°C or lower, and even more preferably at 50°C or lower. <1> ~ <4> A method for removing contaminants as described in any one of the items.

[0047] <6> Preferably, the coating film of the self-peeling composition peels off from the periphery as it dries. <1> ~ <5> A method for removing contaminants as described in any one of the items.

[0048] <7> Preferably, the step of removing contaminants along with the coating film includes a step of recovering the peeled-off dried coating film. <1> ~ <6> A method for removing contaminants as described in any one of the items.

[0049] <8> Component (A) is a polymer having a glass transition temperature of preferably 0°C or higher, more preferably 10°C or higher, even more preferably 20°C or higher, even more preferably 30°C or higher, and also preferably 300°C or lower, more preferably 280°C or lower, even more preferably 260°C or lower, and even more preferably 240°C or lower. <1> ~ <7> A method for removing contaminants as described in any one of the items.

[0050] <9> The weight-average molecular weight of component (A) is preferably 5000 or more, more preferably 7000 or more, even more preferably 10000 or more, and also preferably 10,000,000 or less, more preferably 5,000,000 or less, and even more preferably 2,000,000 or less. <1> ~ <8> A method for removing contaminants as described in any one of the items.

[0051] <10> Component (A) is preferably one or more selected from polyvinyl alcohol, a copolymer with vinyl alcohol as the main structure, cellulose ether, polystyrene sulfonic acid or its salt, acrylic resin, xanthan gum, gellan gum, and guar gum. <1> ~ <9> A method for removing contaminants as described in any one of the items.

[0052] <11> The content of component (A) in the self-peelable film-forming composition is preferably 5% by mass or more, more preferably 7% by mass or more, even more preferably 9% by mass or more, and also preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. <1> ~ <10> A method for removing contaminants as described in any one of the items.

[0053] <12> The target surface is a material with fine irregularities, and the content of component (A) in the self-peelable film-forming composition is preferably 14% by mass or more, more preferably 19% by mass or more, and also preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. <1> ~ <10> A method for removing contaminants as described in any one of the items.

[0054] <13> Component (B) is preferably selected from water and volatile organic solvents, more preferably contains water, and even more preferably has water as its main component. <1> ~ <12> A method for removing contaminants as described in any one of the items.

[0055] <14> The vapor pressure of the volatile organic solvent at 20°C is preferably 0.01 kPa or more and 106.66 kPa or less, more preferably 0.13 kPa or more and 66.66 kPa or less, even more preferably 0.67 kPa or more and 40.00 kPa or less, and even more preferably 1.33 kPa or more and 40.00 kPa or less. <13> The method for removing contaminants described below.

[0056] <15> The proportion of volatile organic solvents in component (B) is 20% by mass or less of the total component (B), furthermore, 10% by mass or less, and furthermore, 5% by mass or less. <13> or <14> The method for removing contaminants described below.

[0057] <16> The content of component (B) in the self-peelable film-forming composition is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and also preferably 92% by mass or less, more preferably 90% by mass or less, even more preferably 80% by mass or less, and even more preferably 70% by mass or less. <1> ~ <15> A method for removing contaminants as described in any one of the items.

[0058] <17> Component (C) has a kinematic viscosity of 6 mm². 2 It is selected from non-volatile dimethylpolysiloxane with a viscosity of 1 / s or more, polyether-modified silicone, amino-modified silicone, and polyglycerol-modified silicone, as well as N-propionylethyleneimine-dimethylsiloxane copolymer. <1> ~ <16> A method for removing contaminants as described in any one of the items.

[0059] <18> The content of component (C) in the self-peelable film-forming composition is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and also preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and even more preferably 7% by mass or less. <1> ~ <17> A method for removing contaminants as described in any one of the items.

[0060] <19> In the self-peelable film-forming composition, the mass ratio (C) / (A) of component (C) to component (A) is preferably 0.01 or higher, more preferably 0.05 or higher, even more preferably 0.07 or higher, and also preferably 1.00 or lower, more preferably 0.7 or lower, and even more preferably 0.5 or lower. <1> ~ <18> A method for removing contaminants as described in any one of the items.

[0061] <20> Use of a composition containing the following components (A) to (C) for removing contaminants from a target surface by self-peeling as the coating film dries. (A) Membrane-forming component (B) Volatile solvents (C) Silicone compound

[0062] <21> A self-peeling film-forming composition containing the following components (A) to (C), wherein the mass ratio of component (C) to component (A), (C) / (A), is 0.01 or more and 1.00 or less. (A) Membrane-forming component (B) Volatile solvents (C) Silicone compound

[0063] <22> Component (A) is a polymer having a glass transition temperature of preferably 0°C or higher, more preferably 10°C or higher, even more preferably 20°C or higher, even more preferably 30°C or higher, and also preferably 300°C or lower, more preferably 280°C or lower, even more preferably 260°C or lower, and even more preferably 240°C or lower. <21> The self-peeling film-forming composition described above.

[0064] <23> The weight-average molecular weight of component (A) is preferably 5000 or more, more preferably 7000 or more, even more preferably 10000 or more, and also preferably 10,000,000 or less, more preferably 5,000,000 or less, and even more preferably 2,000,000 or less. <21> or <22> The self-peeling film-forming composition described above.

[0065] <24> Component (A) is preferably one or more selected from polyvinyl alcohol, a copolymer with vinyl alcohol as the main structure, cellulose ether, polystyrene sulfonic acid or its salt, acrylic resin, xanthan gum, gellan gum, and guar gum. <21> ~ <23> A self-peeling film-forming composition according to any one of the items.

[0066] <25> The content of component (A) is preferably 5% by mass or more, more preferably 7% by mass or more, even more preferably 9% by mass or more, and also preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. <21> ~ <24> A self-peeling film-forming composition according to any one of the items.

[0067] <26> Component (B) is preferably selected from water and volatile organic solvents, more preferably contains water, and even more preferably has water as its main component. <21> ~ <25> A self-peeling film-forming composition according to any one of the items.

[0068] <27> The vapor pressure of the volatile organic solvent at 20°C is preferably 0.01 kPa or more and 106.66 kPa or less, more preferably 0.13 kPa or more and 66.66 kPa or less, even more preferably 0.67 kPa or more and 40.00 kPa or less, and even more preferably 1.33 kPa or more and 40.00 kPa or less. <26> The self-peeling film-forming composition described above.

[0069] <28> The proportion of volatile organic solvents in component (B) is 20% by mass or less of the total component (B), furthermore, 10% by mass or less, and furthermore, 5% by mass or less. <26> or <27> The self-peeling film-forming composition described above.

[0070] <29> The content of component (B) is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and also preferably 92% by mass or less, more preferably 90% by mass or less, even more preferably 80% by mass or less, and even more preferably 70% by mass or less. <21> ~ <28> A self-peeling film-forming composition according to any one of the items.

[0071] <30> Component (C) has a kinematic viscosity of 6 mm². 2It is selected from non-volatile dimethylpolysiloxane with a viscosity of 1 / s or more, polyether-modified silicone, amino-modified silicone, and polyglycerol-modified silicone, as well as N-propionylethyleneimine-dimethylsiloxane copolymer. <21> ~ <29> A self-peeling film-forming composition according to any one of the items.

[0072] <31> The content of component (C) is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and also preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and even more preferably 7% by mass or less. <21> ~ <30> A self-peeling film-forming composition according to any one of the items.

[0073] <32> The mass ratio (C) / (A) of component (C) to component (A) is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.07 or more, and also preferably 1.00 or less, more preferably 0.7 or less, and even more preferably 0.5 or less. <21> ~ <31> A self-peeling film-forming composition according to any one of the items.

[0074] <33> A self-peeling film-forming composition containing the following components (A) to (C), wherein the degree of peeling measured by the evaluation method described below is between 20% and 100%. (A) Membrane-forming component (B) Volatile solvents (C) Silicone compound <Evaluation Method> Apply the composition to an epoxy resin coated substrate at a concentration of 0.3 g / cm³. 2 The coating is applied and allowed to dry for 24 hours. The adhesion area S1 of the composition that has spread wet on the substrate before drying and the area S2 of the coating film that is in contact with the substrate after drying are measured, and the value of (S1-S2) / S1 calculated is defined as the degree of peeling. [Examples]

[0075] Synthesis Example 1: Synthesis Example of N-propionylethyleneimine-dimethylsiloxane copolymer 53.2 g (0.53 mol) of 2-ethyl-2-oxazoline and 127.5 g of ethyl acetate were mixed, and the mixture was dehydrated with 9.0 g of molecular sieve (product name: Zeoram A-4, manufactured by Tosoh Corporation) for 15 hours. In addition, 153.75 g of side-chain primary aminopropyl-modified polydimethylsiloxane (weight-average molecular weight 50000, amine equivalent 2000) and 312.6 g of ethyl acetate were mixed, and the mixture was dehydrated with 22.7 g of molecular sieve for 15 hours. To the ethyl acetate solution of the dehydrated 2-ethyl-2-oxazoline described above, 9.98 g (0.064 mol) of diethyl sulfate was added, and the mixture was heated under reflux at 80°C for 8 hours under a nitrogen atmosphere to synthesize terminally reactive poly(N-propionylethyleneimine). This terminally reactive poly(N-propionylethyleneimine) solution was added in one go to the dehydrated side-chain primary aminopropyl-modified polydimethylsiloxane solution described above, and the mixture was heated under reflux at 80°C for 10 hours. The reaction mixture was concentrated under reduced pressure to obtain the N-propionylethyleneimine-dimethylsiloxane copolymer as a pale yellow rubbery solid (200 g, yield 92%). The mass ratio of organopolysiloxane segments in the final product was 0.70, and the weight-average molecular weight of the final product was 70400 (calculated value). The obtained N-propionylethyleneimine-dimethylsiloxane copolymer was dissolved in ethanol to a solid content concentration of 40% by mass to obtain an ethanol solution of the N-propionylethyleneimine-dimethylsiloxane copolymer.

[0076] Synthesis Example 2: Synthesis Example of a Methacrylic Acid / Methyl Methacrylate Copolymer 50 g of methacrylic acid, 50 g of methyl methacrylate, and 380 g of ethanol were stirred and mixed while bubbling with nitrogen, and the temperature was raised to 60°C. To the resulting mixture, a solution of 0.54 g of 2,2'-azobis(2,4-dimethylvaleronitrile) dissolved in 20 g of ethanol was added dropwise over 30 minutes while stirring at 60°C under a nitrogen atmosphere for 4 hours to synthesize a methacrylic acid-methyl methacrylate copolymer. The reaction mixture was reprecipitated with an acetone-hexane (acetone:hexane = 1:2, volume ratio) mixed solvent, and the resulting precipitate was dried under reduced pressure at 50°C to obtain the methacrylic acid-methyl methacrylate copolymer as a white solid. The mass ratio of constituent units derived from methacrylic acid and methyl methacrylate in the final product was 50% by mass and 50% by mass, respectively (calculated from the initial composition ratio).

[0077] Examples 1-23, Comparative Example 1 The compositions shown in Tables 1-4 were prepared, and the degree of peeling (%) was measured according to the method described below. In the tables, the degree of peeling is indicated by a value, with "A" indicating a peeling degree of 20% or more, and "B" indicating a peeling degree of less than 20%.

[0078] (Method for evaluating the degree of peeling) Each composition is applied to an epoxy resin coated substrate (Tables 1-3) or a cement solidified substrate (Table 4) at a depth of 10 cm. 2 0.3 g / cm³ within the range 2 The sample was prepared by coating the material and drying it at 25°C and 40% RH for 24 hours. The adhesion area S1 of the composition that has spread wet on the substrate before drying and the area S2 of the coating film that is in contact with the substrate after drying are measured, and the value of (S1-S2) / S1 calculated is defined as the degree of peeling.

[0079] <Glass transition temperature> The glass transition point of the polymer of film-forming component (A) described in the examples was determined by DSC measurement under the following conditions on the dried solid obtained by drying each sample at room temperature for 24 hours and then further drying under reduced pressure at 80°C. Measurement device: DSC7000X (Hitachi High-Tech Science Co., Ltd.) Temperature profile: 1. Increase the temperature from 20°C to the target temperature at a rate of 10°C / min, and maintain the temperature for 5 minutes. 2. Cool from the target temperature to 20°C at a rate of 10°C / min and hold for 5 minutes. 3. Increase the temperature from 20°C to the target temperature at a rate of 10°C / min, and hold for 5 minutes. 4. Cool from the target temperature to 20°C at a rate of 10°C / min and hold for 5 minutes. The target temperature was measured at 250°C for Kurarepoval 60-98, 28-98, 5-98, Sunrose APP-84, and the copolymer synthesized in Synthesis Example 2, and at 350°C for PS-100.

[0080] [Table 1]

[0081] [Table 2]

[0082] [Table 3]

[0083] [Table 4]

[0084] *1: Kuraray Poval 60-98 (manufactured by Kuraray Co., Ltd.), Tg 70℃, weight-average molecular weight 106,000 *2: BYK-345 (manufactured by BYK) *3: KF-6011 (manufactured by Shin-Etsu Chemical Co., Ltd.) *4: KF-6204 (manufactured by Shin-Etsu Chemical Co., Ltd.) *5: KF-352A (manufactured by Shin-Etsu Chemical Co., Ltd.) *6: 40% by mass ethanol solution of the N-propionylethyleneimine-dimethylsiloxane copolymer prepared in Synthesis Example 1 *7: Kuraray Poval 5-98 (manufactured by Kuraray Co., Ltd.), Tg 60℃, weight-average molecular weight 22,000 *8: Kuraray Poval 28-98 (manufactured by Kuraray Co., Ltd.), Tg 70℃, weight-average molecular weight 75,000 *9: SILSOFT EM341N (manufactured by Momentive Performance Materials Japan) *10: DOWSIL SM8904 cosmetic emulsion (manufactured by Dow-Toray) *11: DOWSIL CF-2460 (manufactured by Dow-Toray) *12: BELSIL DM 3102 E (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) *13: Kuraray Poval 22-88 (manufactured by Kuraray Co., Ltd.), Tg 60℃, weight-average molecular weight 75,000 *14: Exepearl RS2117 (manufactured by Kuraray Co., Ltd.), Tg 63℃, weight-average molecular weight 75,000 *15: Echogum LAX-T (manufactured by DSP Gokyo Food & Chemical Co., Ltd.), Tg 82℃, weight-average molecular weight 2,000,000 *16: Kerkogel HM (manufactured by CP Kerko), Tg 140℃, weight-average molecular weight 500,000 *17: Labor Gum CG-M (manufactured by DSP Gokyo Food & Chemical Co., Ltd.), Tg 130℃, weight-average molecular weight 300,000 *18: Sunrose APP-84 (manufactured by Nippon Paper Industries), Tg 120℃, weight-average molecular weight 17,000 *19: PS-100 (manufactured by Tosoh Finechem Co., Ltd.), Tg 220℃, weight-average molecular weight 700,000 *20: Methacrylic acid / methyl methacrylate copolymer synthesized in Synthesis Example 2 (neutralized to pH 7 using NaOH), Tg 170℃, weight-average molecular weight 130,000 *21: Sofcare GS-G (manufactured by Kao Corporation)

[0085] The film strength of the compositions in Examples 1, 6, 10, 15, 20, and 22 was evaluated according to the method described below. The results are shown in Table 5. (Membrane strength) The composition was dried on a glass plate or Teflon sheet in an environment of 25°C and 50% RH humidity to obtain a dry film with a dry thickness of 500 μm. When the obtained film was bent 90° or folded 180° and then unfolded, those that did not break were designated as a, those that broke were designated as c, and those that showed creases or cracks but did not break were designated as b.

[0086] [Table 5]

Claims

1. A method for removing contaminants adhering to a target surface, comprising the steps of: applying a self-peeling film-forming composition containing components (A) to (C) to the target surface to which the contaminants are adhering to form a coating film; drying the coating film; and removing the contaminants together with the coating film by the self-peeling of the coating film during drying. A method for removing contaminants, comprising the following features. (A) Membrane-forming component (B) Volatile solvents (C) Silicone compound

2. The method for removing contaminants according to claim 1, wherein the step of removing contaminants together with the coating film includes a step of recovering the peeled-off dried coating film.

3. The method for removing contaminants according to claim 1 or 2, wherein the coating film of the self-peeling composition peels off from the periphery as it dries.

4. The amount of self-peeling composition applied to the target surface is 0.1 kg / m². 2 The above describes the method for removing pollutants according to any one of claims 1 to 3.

5. A method for removing contaminants according to any one of claims 1 to 4, wherein the drying process is carried out in an environment of -10°C or higher and 60°C or lower.

6. The method for removing contaminants according to any one of claims 1 to 5, wherein component (A) is a polymer having a glass transition temperature of 0°C or higher and 300°C or lower.

7. A method for removing contaminants according to any one of claims 1 to 6, wherein component (A) is one or more selected from polyvinyl alcohol, a copolymer having vinyl alcohol as its main structure, cellulose ether, polystyrene sulfonic acid or a salt thereof, acrylic resin, xanthan gum, gellan gum, and guar gum.

8. A method for removing contaminants according to any one of claims 1 to 7, wherein component (B) contains water.

9. Use of a composition containing the following components (A) to (C) for removing contaminants from a target surface by self-peeling as the coating film dries. (A) Membrane-forming component (B) Volatile solvents (C) Silicone compound

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