JP5540917B2 - Paint remover - Google Patents

Description

  The present invention relates to a coating release agent that peels off a coating film adhering to an object support used when electrodeposition coating is applied to an object to be coated.

  In order to improve the corrosion resistance and decorativeness of coated objects such as automobile bodies, the coated object is immersed in the coating layer as a cathode or an anode, and an electric current is passed between the other electrode, so that Electrodeposition coating is performed in which a coating film is formed on an object by electrophoresis.

  In general, when coating a coated object, the coated object is installed on a coated support used as an electrodeposition coating jig such as a hanger, an angle, or a carriage, and the coated object is suspended. The object to be coated is dipped in an electrodeposition solution that is held in a state and contains the coating material of the electrodeposition tank. In electrodeposition coating, an electric current is passed through the object support through the object support that holds the object to be coated, so when the object is painted, it is applied to the part of the object support that is immersed in the paint. The paint is applied and the paint adheres.

  Unnecessary coating film adhering to such a substrate support is insulated at the painted portion of the substrate support, so that it is difficult for the current to flow through the substrate the next time it is applied. May cause troubles in painting equipment. For this reason, when using a substrate support for painting a new substrate, unnecessary coatings that have adhered to the substrate support are usually applied before the new substrate is painted. Has been removed.

  Therefore, conventionally, in order to remove such an unnecessary coating film, generally, a method has been proposed in which a coating release agent for coating is applied to the surface of the coating film or is immersed in the coating release agent for peeling. For example, a stripping solution containing an acidic solution or an alkaline solution such as aqueous hydrogen peroxide or nitric acid is used as a coating stripper, and the coating substrate support is immersed in this stripping solution and is not attached to the coating substrate support. There is a method for peeling a thin coating film (for example, see Patent Documents 1 and 2).

Japanese Patent Application Laid-Open No. 08-311374 JP 63-121848 A

  However, since the conventional paint release agent is an acidic or alkaline release solution, there is a problem that the substrate support may be corroded by acid or alkali.

  In addition, the coating film formed by electrodeposition coating on the object to be coated has high adhesion and adheres firmly to the object support, so that it adheres to the object to be coated only by dipping in a conventional stripping solution. There was a problem that it was difficult to completely remove the coating film in a short time. Moreover, there existed a problem that the coating film which peeled and floated in the peeling tank might adhere again to an electrodeposition coating jig.

  In addition, there is a method using a blasting method in which the coating substrate is immersed in a stripping solution, and then the coating is impacted by brushing or powder or water sprayed at high speed and high pressure to peel the coating. When the method is used, there are problems that the peeling process of the coating film is increased and the efficiency is poor, and there is a possibility that deformation or damage of the support to be coated is caused.

  In view of the above problems, the present invention is to provide a coating release agent that can easily and efficiently peel a coating film and reduce corrosion of an object support.

The present invention includes the following (1) to (3).
(1) A paint release agent comprising an aliphatic cyclic epoxy resin and having a pH of 6.5 to 7.5.
(2) Including the water-insoluble imidazole compound in the aliphatic cyclic epoxy resin,
The coating release agent according to (1), wherein the content of the water-insoluble imidazole compound is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the aliphatic cyclic epoxy resin.
(3) The coating release agent according to (2), wherein the water-insoluble imidazole compound is a triazine-modified compound or a water-insoluble imidazole-isocyanuric acid adduct.

  ADVANTAGE OF THE INVENTION According to this invention, the coating release agent which can perform peeling of a coating film easily and efficiently, and can reduce the corrosion of a to-be-coated substrate can be provided.

  The present invention will be described in detail below. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

  The coating release agent of this embodiment is demonstrated. The present invention is a paint release agent containing an aliphatic cyclic epoxy resin and having a pH of 6.5 to 7.5.

<Aliphatic cyclic epoxy resin>
The aliphatic cyclic epoxy resin contained in the paint release agent of this embodiment is an epoxy resin containing an aliphatic ester bond in the molecule. The aliphatic cyclic epoxy resin is contained as a main component in the paint release agent of this embodiment. In this embodiment, the “main component” means 60 parts by mass or more. That is, the content of the aliphatic cyclic epoxy resin in the paint release agent of this embodiment is 60 parts by mass or more. This ratio is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 100 parts by mass, that is, substantially free of other components.

  Since the aliphatic cyclic epoxy resin has a neutral pH, the pH of the coating release agent of the present embodiment can be neutral, and is suitable for use as a coating release agent for a coating film. In the present embodiment, neutral means that the pH of the solution is in the range of 6.5 to 7.5.

  The aliphatic cyclic epoxy resin is not particularly limited for its production. For example, it can be synthesized by a method of introducing an epoxy group by adding oxygen to a double bond in a molecule using a peroxide such as peracetic acid during epoxidation. The aliphatic cyclic epoxy resin includes a group having an epoxy group in the aliphatic cyclic hydrocarbon represented by the following general formula (1), and any of the structures represented by the following general formulas (2) to (4) Is included.

  Examples of such aliphatic cyclic epoxy resins include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylethyl-3,4-epoxycyclohexanecarboxylate, and vinylcyclohexene diene. Oxide, allyl cyclohexylene dioxide, 3,4-epoxy-4-methylcyclohexyl-2-propylene oxide, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-m-dioxane Bis (3,4-epoxycyclohexyladipate), bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxycyclohexyl) ether, bis (3,4-epoxycyclohexylmethyl) ether, (3,4-epoxycyclohexyl) diethylsiloxane, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, 2,3-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxy 4- (3,4-epoxy-5-methylcyclohexyl) butyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4- And epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate. The aliphatic cyclic epoxy resins may be used alone or in combination of two or more.

  Specific examples of the aliphatic cyclic epoxy resin include “YL-6663” and “YL-6653” manufactured by Mitsubishi Chemical Corporation, “Araldite CY-184” and “Araldite CY-192” manufactured by Ciba Specialty Chemicals. 1 ”,“ Araldite CY-179 ”,“ Araldite CY-177 ”,“ Celoxide 2021P ”,“ Celoxide 2081 ”,“ Celoxide 2083 ”,“ Celoxide 3000 ”,“ Epolide GT301 ”,“ Epolide ”manufactured by Daicel Chemical Industries, Ltd. GT302 "," Epolide GT401 "," Epolide GT403 ", etc. (all are trade names).

<Water-insoluble imidazole compound>
The paint release agent of this embodiment may contain a water-insoluble imidazole compound in the aliphatic cyclic epoxy resin. The imidazole compound is a compound composed of an imidazole derivative having an unshared electron pair. The imidazole derivative functions as a cation receptor. In the present embodiment, the cation includes a proton. In this case, the imidazole derivative becomes an imidazole compound. Since the imidazole compound is difficult to dissolve in water and is insoluble in water, the imidazole compound contained in the aliphatic cyclic epoxy resin is insoluble in water. Since the pH of this water-insoluble imidazole compound is neutral, the pH of the coating release agent of this embodiment can be neutral, and is suitable for use as a coating release agent for coating films.

  As the water-insoluble imidazole compound, for example, a compound having a substituent in at least one of the 1-position, 2-position, 4-position and 5-position of imidazole as shown in the following general formula (5), the following general formula (6 ) A compound in which the 4-position and 5-position of imidazole are cyclized, a compound in which the 1-position and 2-position of imidazole are cyclized as shown in the following general formula (7), or the following general formula (8 And the like are compounds in which the 1-position and 5-position of imidazole are cyclized.

（化５において、Ｒ１、Ｒ２、Ｒ３およびＲ４は、水素基あるいは置換基を表す。それらは同一でも異なっていてもよい。但し、少なくとも１つは置換基であることが必要である。）

(In Chemical Formula 5, R1, R2, R3 and R4 represent a hydrogen group or a substituent. They may be the same or different. However, at least one of them must be a substituent.)

（化６において、Ｒ１およびＲ２は、水素基あるいは置換基を表す。それらは同一でも異なっていてもよい。Ｒ５は、炭素を含む基を表す。）

(In Chemical Formula 6, R1 and R2 represent a hydrogen group or a substituent. They may be the same or different. R5 represents a group containing carbon.)

（化７において、Ｒ３およびＲ４は、水素基あるいは置換基を表す。それらは同一でも異なっていてもよい。Ｒ６は、炭素を含む基を表す。）

(In Chemical Formula 7, R3 and R4 represent a hydrogen group or a substituent. They may be the same or different. R6 represents a group containing carbon.)

（化８において、Ｒ２およびＲ３は、水素基あるいは置換基を表す。それらは同一でも異なっていてもよい。Ｒ７は、炭素を含む基を表す。）

(In Chemical Formula 8, R2 and R3 represent a hydrogen group or a substituent. They may be the same or different. R7 represents a group containing carbon.)

  The substituents R1 to R4 may be carbon-containing substituents or halogen groups, but are preferably carbon-containing substituents. The substituent having carbon is preferably one having 1 to 20 carbon atoms. This is because if the carbon number is larger than 20, the mobility of the cation is lowered. The substituent having carbon may contain a heteroatom such as nitrogen (N), oxygen (O), phosphorus (P), or sulfur (S).

  Furthermore, examples of the substituent having carbon include an alkyl group, an aryl group, and a group in which at least one hydrogen of these groups is substituted with a halogen. Among these, a phenyl group, a benzyl group, an alkyl group having 1 to 17 carbon atoms, or a group in which at least one hydrogen of these groups is substituted with a halogen is preferable. The imidazole derivative itself becomes difficult to dissolve in water, and the solubility of the imidazole compound can be reduced.

  Moreover, since the solubility to water becomes low, so that the imidazole derivative which has an unshared electron pair is multi-substituted, it is preferable that an imidazole derivative is multi-substituted.

  For example, such imidazole derivatives include 2-i-propylimidazole as shown in the following general formula (9), 2-ethylimidazole as shown in the following general formula (10), and as shown in the following general formula (11). 2-n-propylimidazole, 2-butylimidazole as shown in the following general formula (12), 2-phenylimidazole as shown in the following general formula (13), and the like. Preferred are those bonded and hydrogen bonded at positions 1, 4 and 5.

  In addition, as shown in the following general formula (14), a hydrogen group is bonded to the 1 position and a substituent is bonded to the 2 position, such as 2-ethyl-4-methyl-imidazole. An imidazole derivative having a substituent bonded to at least one of the positions is also preferred.

  Examples of the water-insoluble imidazole compound include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-benzyl-2-phenylimidazole, and 2-phenyl. -4-methyl-5-hydroxymethylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- (2-cyanoethyl) -2-ethyl-4-methyl Examples include imidazole. The water-insoluble imidazole compounds may be used alone or in combination of two or more.

  The water-insoluble imidazole compound may be a triazine-modified compound or a water-insoluble imidazole-isocyanuric acid adduct obtained by adding an isocyanuric acid represented by the following general formula (15) to the water-insoluble imidazole compound.

Examples of the compound obtained by triazine modification of a water-insoluble imidazole compound include 2,4-diamino-6- [2′-methylimidazolidyl (1 ′)]-ethyl-s-triazine,
2,4-diamino-6- [2′-ethyl-4-methylimidazole- (1)]-ethyl-S-triazine represented by the chemical formula (7) is exemplified.

  The water-insoluble imidazole-isocyanuric acid adduct is obtained by adding the isocyanuric acid shown in the above general formula (15) to a water-insoluble imidazole compound. A compound obtained by adding isocyanuric acid to a compound obtained by modifying an imidazole compound with triazine is also included. Examples of the water-insoluble imidazole-isocyanuric acid adduct include 2,4-diamino-6- [2'-methylimidazolidyl- (1 ')]-ethyl-s-triazine isocyanuric acid adduct.

  The water-insoluble imidazole-isocyanuric acid adduct can be synthesized by reacting a water-insoluble imidazole compound and isocyanuric acid in a solvent. The water-insoluble imidazole compound and isocyanuric acid react stoichiometrically. That is, the usage-amount of a water-insoluble imidazole compound and isocyanuric acid is made to become 1: 1 on a molar ratio.

  As a synthesis method, for example, a slurry in which a water-insoluble imidazole compound and isocyanuric acid are suspended in water is prepared, and the slurry is heated for a predetermined time while stirring, and then the slurry (reaction solution) is cooled. The precipitate (reaction product) is isolated by filtration. The reaction product is washed and dried and heated according to a conventional method. Thereby, an imidazole-isocyanuric acid adduct is obtained. Although the reaction temperature is not particularly limited, the amount of the imidazole-isocyanuric acid adduct can be increased by increasing the amount of the raw material dissolved in the solvent to reduce the amount of the solvent used or by increasing the dissolution rate of the raw material in the solvent. From the viewpoint of increasing the efficiency of synthesis, it is preferable to increase the reaction temperature within a range that does not affect the reaction. Moreover, the solvent used at the time of synthesis is not particularly limited as long as it can dissolve isocyanuric acid, and examples thereof include water and isopropyl alcohol which are inexpensive and can be easily treated with a waste liquid. In order to improve the purity of the imidazole-isocyanuric acid adduct, the amount of solvent used is 5 to 10 times (mass ratio) with respect to the total amount of imidazole compound and isocyanuric acid as raw materials. More is preferable.

  The water-insoluble imidazole compound is preferably contained in an amount of 1 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, with respect to 100 parts by mass of the aliphatic cyclic epoxy resin. More preferably, the content is 10 parts by mass or less. It is because the peeling effect of the coating film by having mix | blended the water-insoluble imidazole compound will not be acquired when content of a water-insoluble imidazole compound is less than 1 mass part. When the content of the water-insoluble imidazole compound exceeds 50 parts by mass, the water-insoluble imidazole compound hardly dissolves in the aliphatic cyclic epoxy resin, so even if the content of the water-insoluble imidazole compound exceeds 50 parts by mass, It is because the peeling effect of the coating film as much as the water-insoluble imidazole compound is blended cannot be obtained.

  Thus, the paint release agent of this embodiment is a paint release agent containing an aliphatic cyclic epoxy resin and having a pH of 6.5 or more and 7.5 or less. Since the pH of the aliphatic cyclic epoxy resin is neutral, the pH of the coating release agent containing the aliphatic cyclic epoxy resin can also be neutral. For this reason, when the coating release agent of this embodiment is used as a release liquid for peeling off the coating film attached to the substrate support that holds the object to be coated, the coating release agent of this embodiment is covered with the coating release agent. Even when the coating support is immersed and the coating film is peeled off, the coating release agent of the present embodiment is a neutral stripping solution, and therefore it is possible to suppress corrosion of the coating support.

  In addition, the electrodeposition coating film formed by electrodeposition coating on the object has high adhesion and adheres firmly to the object support, so that it can be applied to the object only by dipping in a conventional stripping solution. It is difficult to completely remove the adhered coating film in a short time. Moreover, there exists a possibility that the coating film which peeled and floated in the peeling tank may adhere again to the to-be-coated object support body which is an electrodeposition coating jig. Further, there is a method using a blasting method in which the coating substrate is immersed in a stripping solution, and then the coating film is impacted by brushing, powder or water sprayed at high speed and high pressure, and the coating film is stripped. When this blasting method is used, the coating film peeling process increases, the efficiency is poor, and there is a risk of deformation or damage of the substrate support. On the other hand, the coating release agent of this embodiment includes a water-insoluble imidazole compound in the aliphatic cyclic epoxy resin, thereby maintaining the pH of the coating release agent of this embodiment neutral and supporting the object to be coated. The peeling effect of the coating film adhering to the body can be improved. For this reason, after dipping the substrate to be coated in a stripping solution, the coating film adhering to the substrate to be coated can be completely removed in a short time and the coating film can be reattached to the substrate to be coated. Can be prevented. Further, if the coating release agent of the present embodiment is used, it is not necessary to use the blast method, so that the coating film peeling process is not increased, and deformation or damage of the substrate support is not caused. For this reason, peeling of a coating film can be performed easily and efficiently. Therefore, the coating release agent of the present embodiment can easily and efficiently peel the electrodeposition coating film, and can reduce corrosion of the object support.

  In addition to the aliphatic cyclic epoxy resin and the water-insoluble imidazole compound, the paint release agent of the present embodiment can contain a surfactant as necessary within a range not impairing the object of the present invention. . The surfactant blended in the coating release agent of the present embodiment is blended for improving wettability when applied to the painted surface. Examples of the surfactant include alkane sulfonate, alkyl sulfate, polyoxyethylene alkyl sulfate, fatty acid salt, linear alkyl benzene sulfonate, alpha olefin sulfonate, polyoxyethylene alkyl ether phosphate, alkyl Examples include amine oxide, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, fatty acid diethanolamide, sorbitan fatty acid ester, glycerin fatty acid ester, and polyoxyethylene polyoxypropylene glycol. The surfactant can be used by mixing one or more of these.

  In the present embodiment, the aliphatic cyclic epoxy resin and the water-insoluble imidazole compound are preferably mixed immediately before use. Therefore, it is necessary to fill each component in a separate container, or to fill a container in which the inside of the container is separated and both components can be stored in an unmixed state. In order to mix these components, one component may be mixed while being added to the other component, or a predetermined amount of both components may be mixed in another container.

  When the paint adhered to the substrate support is peeled off, it may be immersed in a tank containing the paint remover of this embodiment, or the paint remover of this embodiment may be applied to the coating surface to be peeled off. -You may make it apply | coat using well-known application | coating means, such as a brush and a roller, and may peel the coating material adhering to a to-be-coated object support body.

  The coating release agent of the present embodiment is easy and efficient for peeling the electrodeposition coating film, and is excellent in reducing corrosion of the substrate to be coated. For example, automobiles, vehicles (Shinkansen, trains), civil engineering Peeling off the coating film attached to the substrate support used to suspend the coating object when electrodeposition coating is applied to the coating material such as construction, electronics, aircraft, and space industry. It can be suitably used as a liquid.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

<Examples 1 to 12 and Comparative Examples 1 to 9>
[Electrodeposition coating]
As the object to be coated, a plate-shaped test piece (0.8 mm × 70 mm × 150 mm) made of SPCC-SD was used. After fixing a test piece to a to-be-coated object support (product made from SPCC-SD), the electrodeposition coating was given to the surface of the to-be-coated object using the cationic electrodeposition coating material based on an epoxy resin. After conducting the energization treatment under the following electrodeposition coating conditions, washing with water and preliminary drying were performed, followed by heat curing to form a coating film having a thickness of 15 μm.
(Conditions for electrodeposition coating)
-Electrodeposition paint: Saxade S # 30S gray, manufactured by Shinto Paint Co., Ltd.-Electrodeposition liquid temperature: 28 ° C
・ Painting voltage: 200V
・ Energization time: 180s
Heat curing: 170 ° C x 20min

[Paint peeling]
The components shown in Tables 1 and 2 were blended in the addition amounts (parts by mass) shown in the same table, and these were uniformly mixed to prepare the coating release agents shown in Tables 1 and 2. The amount (parts by mass) of each component in each example and comparative example is as shown in Tables 1 and 2. Using the coating release agents obtained by preparing the components shown in Tables 1 and 2 in the blending amounts shown in Tables 1 and 2, using the test strips obtained as described above in the release solution under the following release conditions Soaked.
(Peeling condition)
-Liquid temperature of stripping solution: 20 ° C
・ Immersion time: 3 minutes

Table 3 shows the pH of the water-insoluble imidazole compound used as a component of each paint remover used in each Example and Comparative Example, the presence or absence of water solubility, the molecular weight, and the position of the substituent bonded to the imidazole derivative. Show. In Table 3, pH is the result of visual observation with pH test paper. Water-soluble double circles, circles, and crosses indicate the following states, respectively. In addition, -Me which shows the substituent couple | bonded with an imidazole derivative shows a methyl group, -Et shows an ethyl group, -Ph shows a phenyl group, -MeOH shows methanol.
(Water soluble)
Double circle: Not soluble in water Circle: Partially soluble in water X: Dissolved in water

[Peeling effect]
The degree of peeling of the coating film on the test piece was confirmed visually. Tables 1 and 2 show the observation results of the peeled state of the coating film. In Tables 1 and 2, double circle marks, circle marks, and cross marks indicate the following states, respectively.
(Peeled state of coating film)
Double circle mark: The coating film is completely peeled off after about 1 or 2 hours after immersing the coating in the stripping solution. Circle: After immersing the coating in the stripping solution until the coating film is completely stripped. Cross mark that takes more than a day: Even if the object to be coated is immersed in a stripping solution, the coating does not peel

The components shown in Tables 1 and 2 are as follows.
Aliphatic cyclic epoxy resin: Celoxide 2021P, manufactured by Daicel Chemical Industries, Ltd. Sodium hydroxide: Wako Pure Chemical Industries, Ltd. Hydrogen peroxide: Wako Pure Chemical Industries, Ltd. Diethylene glycol diethyl ether: Wako Pure Chemical Industries, Ltd. Benzyl Alcohol: manufactured by Kanto Chemical Co., Inc., bisphenol A type epoxy resin: JER834, manufactured by Mitsubishi Chemical Co., Ltd., 2-undecylimidazole: Curesol C11Z, manufactured by Shikoku Kasei Kogyo Co., Ltd., 2-phenylimidazole: Curazole 2PZ, manufactured by Shikoku Kasei Kogyo Co., Ltd. -Benzyl-2-phenylimidazole: Curezol 1B2PZ, manufactured by Shikoku Kasei Kogyo Co., Ltd. 2-Phenyl-4-methyl-5-hydroxymethylimidazole: Curezol 2P4MHZ-PW, manufactured by Shikoku Kasei Kogyo Co., Ltd., 2-heptadecylimidazole: Curezol C17Z 2,4-diamino-6- [2'-methylimidazolidyl- (1 ')]-ethyl-s-triazine: Curezol 2MZ-A, Shikoku Kasei Kogyo Co., Ltd., 2,4-diamino -6- [2'-methylimidazolidyl- (1 ')]-ethyl-s-triazine isocyanuric acid adduct: Curesol 2MA-OK, manufactured by Shikoku Kasei Kogyo Co., Ltd., nitric acid: nitric acid 1.38, manufactured by Kanto Chemical Co., Inc. Ammonia: ammonia water, manufactured by Wako Pure Chemical Industries, Ltd., 1,2-dimethylimidazole: 1,2-DMZ, manufactured by Shikoku Chemicals Co., Ltd., 2-ethyl-4-methylimidazole: 2E4MZ, manufactured by Shikoku Chemicals Co., Ltd., 1- Cyanoethyl-2-methylimidazole: 2MZ-CN, manufactured by Shikoku Chemicals

  As shown in Table 1, in Example 1, since the coating film could be peeled off from the object to be coated, the effect of peeling off the coating film from the test piece was obtained even with only the aliphatic cyclic epoxy resin as a component of the coating release agent. It was confirmed that In Examples 2 to 12, as a component of the coating release agent, in addition to the aliphatic cyclic epoxy resin, 2-undecylimidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, 2-phenyl-4-methyl -5-hydroxymethylimidazole, 2-heptadecylimidazole, 2,4-diamino-6- [2'-methylimidazolidyl (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [ Even when 2′-methylimidazolidyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct was blended, the pH of the coating release agent could be kept neutral. Moreover, the coating film was able to be peeled from the test piece in a shorter time. Therefore, by adding a water-insoluble imidazole compound in addition to the aliphatic cyclic epoxy resin as a component of the coating release agent, it is possible to accelerate the peeling of the coating film of the coating object, and to apply the coating material in a shorter time. It was confirmed that the film could be peeled off.

  On the other hand, in Comparative Examples 1 to 4, the coating film could be peeled from the test piece, but the pH of the coating release agent was acidic or alkaline. Moreover, in Comparative Examples 5 and 6, although the pH of the coating release agent was neutral, the coating film could not be peeled from the test piece. Therefore, it was confirmed that even if an epoxy containing an aromatic ring such as a bisphenol A type epoxy resin is used as a component of the coating release agent, the peeling effect of the coating film to be coated cannot be obtained. In Comparative Example 6, the pH of the coating release agent was neutral, but the coating film could not be peeled off from the object to be coated. Since the bisphenol A type epoxy resin does not provide the effect of removing the coating film of the object to be coated, even if a water-insoluble imidazole compound such as 2-undecylimidazole is used as a component of the paint release agent, As a result, it was confirmed that the coating film could not be peeled off from the article to be coated only with the water-insoluble imidazole compound. Moreover, in Comparative Examples 7 to 9, the coating film could be peeled off from the object to be coated, but the pH of the coating release agent was alkaline. Therefore, when 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, or 1-cyanoethyl-2-methylimidazole is added in addition to the aliphatic cyclic epoxy resin as a component of the coating release agent, Dimethylimidazole, 2-ethyl-4-methylimidazole and 1-cyanoethyl-2-methylimidazole are water-soluble, and 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole and 1-cyanoethyl-2-methylimidazole Since the pH of the coating is alkaline, even if the coating film can be peeled off from the coating object, it has been confirmed that the pH of the coating release agent becomes alkaline and is not preferable.

  Therefore, as in Examples 1 to 12, in addition to the aliphatic cyclic epoxy resin as a component of the coating release agent, a predetermined amount of a water-insoluble imidazole compound is further included so that the effect of peeling off the coating film of the object to be coated has been achieved. The pH of the coating release agent can be neutral while having the same as that of the coating film, so that the coating film can be peeled off easily and efficiently and the corrosion of the substrate to be coated is reduced. Can do. Therefore, the paint release agent of the present invention can be used as a paint release agent used to release a coating film attached to an object support that supports an object such as an automobile body.

  As described above, since the paint release agent according to the present invention is excellent in reducing corrosion of an object support, a coating film attached to an object support that supports an object such as an automobile body is applied. It is suitable for use as a paint remover used for peeling.

Claims (3)

  A paint remover comprising an aliphatic cyclic epoxy resin and having a pH of 6.5 to 7.5. Including the water-insoluble imidazole compound in the aliphatic cyclic epoxy resin,
The coating release agent according to claim 1, wherein the content of the water-insoluble imidazole compound is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the aliphatic cyclic epoxy resin.   The coating remover according to claim 2, wherein the water-insoluble imidazole compound is a triazine-modified compound or a water-insoluble imidazole-isocyanuric acid adduct.