JPH072923B2 - Cleaning agent for removing protective coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning agent for removing a protective coating (hereinafter, simply referred to as "cleaning agent"). More specifically, the present invention relates to a cleaning agent capable of easily removing a protective coating film on a vehicle body surface even after a large vehicle such as an automobile is stored for a long period of time.

[Conventional technology]

For large vehicles such as automobiles, motorcycles, and agricultural tillers, a water-soluble resin-based protective coating such as a water-soluble acrylic resin (for example, Japanese Patent Publication No. 55 The protective composition disclosed in JP-A-50517) is applied. To remove the protective coating film formed by this protective coating, conventionally, a method of spraying a warm dilute aqueous alkaline solution as a cleaning agent, or applying and dissolving the protective coating film in a dilute alkaline aqueous solution to remove it. Is being done. However, the time when the above cleaning agent can be applied is about 1 to 2 weeks after the protective coating is applied to the vehicle outer panel after the assembly is completed, and after that, the protective coating film can be removed. Disappear. After the car is completed, it is stored outdoors for 2-3 months, and the car to be exported is often left outdoors for more than 6 months depending on the area if the period of sea transportation is added. Thus, the protective coating film exposed outdoors for a long period of time deteriorates under the influence of heat, ultraviolet rays, earth and sand, water, etc., and its removability in alkaline water extremely decreases.

As a method for removing the protective coating film thus having poor removability, for example, the protective coating film is wiped off with an organic solvent type paint remover such as an alcohol type disclosed in JP-A-52-24926. There is a way to remove it. However, with an organic solvent-based paint remover, although a small amount of removal work can be done,
It takes too much man-hours and / or time to perform a large amount of removing work, which is inefficient and uneconomical. Further, when a large amount of the organic coating film peeling agent is used, there are problems of danger of ignition and safety for human body, and also problems of discharge treatment because washing with water is also used at the time of removal.

As described above, the technology for removing protective coatings has a high level of cleaning performance even for protective coatings that have been used for a long period of time, there is no risk of ignition, it is safe for the human body, and it is treated for discharge. The reality is that no detergent has been found that has no problem with its sex.

[Problems to be solved by the invention]

It is an object of the present invention to provide a cleaning agent that does not have the above problems. In other words, it aims to provide a cleaning agent having the following properties.

(1) Maintaining high cleanability even after a long period of time has passed since the application of the paint for protecting outer panels of automobiles and the like.

(2) There is no risk of ignition.

(3) It is safe for the human body.

(4) There is no problem in wastewater treatment.

[Means for solving problems]

As a result of detailed investigations on the deterioration of the coating film after the protective coating has passed for a long period of time, the inventors have found that the coating film locally causes a crosslinking reaction, and that the acid groups in the polymer cause calcium due to earth and sand or water. It has been found that it becomes impossible to remove with a single alkaline water because it becomes a metal salt such as magnesium. Based on this knowledge, as a result of diligent research on the components, composition, etc. of the cleaning agent that affect the cleaning performance in the removal, as a result, it contains a specific water-soluble amine, polyhydric alcohol derivative or alcohol, a specific surfactant and a sequestering agent. The composition has excellent performance as a cleaning agent,
They found that they exhibited particularly excellent cleaning performance, and completed two types of cleaning agents.

That is, the cleaning agent of the first invention is (A) a water-soluble amine, (B) an aliphatic polyhydric alcohol derivative or an aliphatic saturated monohydric alcohol having 1 to 3 carbon atoms, (C) a metal ion A detergent comprising a blocking agent and (D) water. Suitable examples of this detergent include (A) content of 10 to 30 parts by weight, (B) content of 3 to 15 parts by weight, (C) content of 1 to 10 parts by weight, and (D). Is 45 to 86 parts by weight.

The cleaning agent of the second invention is (A) a water-soluble amine, (B) a polyhydric alcohol derivative or alcohol, (C) a sequestering agent, (D) a water ion (E) an anionic surfactant or a nonionic surfactant. It is a cleaning agent characterized by comprising. Suitable examples of this detergent include (A) content of 10 to 30 parts by weight, (B) content of 3 to 15 parts by weight, (C) content of 1 to 10 parts by weight, (D) The content of (E) is 45 to 86 parts by weight, and the content of (E) is 0.1 to 5 parts by weight.

In the first and second inventions, a part of the water-soluble amine can be replaced with one or more selected from concentrated ammonia water, potassium hydroxide, sodium hydroxide and silicate.

(Water-soluble amine) Examples of the water-soluble amine include diethylamine, triethylamine, ethylenediamine, monoethanolamine, diethanolamine, 2-amyl-2-methylpropanol, morpholine, aminoethylethanolamine, dimethylethanolamine and diethylethanolamine. Can be used. Particularly, monoethanolamine, 2-amino-2-methylpropanol and morpholine are effective and preferable.

(Polyhydric alcohol derivative or alcohol) As the polyhydric alcohol derivative, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol isopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, Propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether and the like can be used.

Further, the above alcohol has 1 to 3 carbon atoms.
Of saturated monohydric alcohol, especially ethanol, n
-Propanol and isopropanol are preferred.

(Sequestering agent) As the sequestering agent, ethylenediaminetetraacetic acid salt, condensed phosphate, dihydroxyethylglycine, gluconic acid, citric acid, tartaric acid, nitrilotriacetic acid salt, N-hydroxyethylethylenediamine-N, N ′, N ″ −
Triacetate, diethylenetriaminepentaacetic acid salt, triethylenetetramine hexaacetic acid salt, hydroxyethyliminodiacetic acid salt, dihydroxyethylglycine and the like can be used.
In particular, ethylenediaminetetraacetic acid salt, diethylenetriaminepentaacetic acid salt and triethylenetetraminehexaacetic acid salt are preferable.

(Surfactant) Examples of the surfactant include anionic surfactants such as fatty acid soaps, sulfate ester salts, sulfonates and phosphates, and polyoxyethylene-based, polyhydric alcohol-based and alkylol-based surfactants. Nonionic surfactants can be used.

(Content Ratio of Essential Ingredients) The cleaning agent described in this specification is used after being diluted 2 to 20 times with water at the time of use as described below. If retained, it will exhibit satisfactory performance when diluted.

(A) Content of water-soluble amine is 10 to 30 parts by weight, (B) Content of polyhydric alcohol derivative or alcohol is 3 to 15 parts by weight, (C) Content of sequestering agent is 1 to 10 parts by weight Parts, (D) water content is 45 to 86 parts by weight, (E) anion surfactant or nonionic surfactant content is 0.1 to 5 parts by weight.

When the content of the water-soluble amine is less than 10 parts by weight, the removability of the protective coating film becomes poor, and when it exceeds 30 parts by weight, not only the coated surface is adversely affected but also the human body is not good.

If the content of the polyhydric alcohol derivative or alcohol is less than 3 parts by weight, excellent removal performance of the protective coating cannot be obtained.
When it exceeds the weight part, flammability and waste water treatment become problems.

If the content of the sequestering agent is less than 1 part by weight, there is no effect on the removability of the protective coating film, and if it exceeds 10 parts by weight, the waste water treatment property becomes a problem.

The surfactant acts to improve the water washability after removing the protective coating film, and if the content thereof exceeds 5 parts by weight, the water washability after removal is not improved and the waste water treatability is rather deteriorated. Absent.

(Other Optional Components) In the cleaning agent of the present invention, an anticorrosive additive such as benzotriazole or metasilicate, a silicone oil-based defoaming agent, and the like can be used as optional components, if necessary.

(Production Method and Usage Method) The detergent of the present invention can be easily produced by mixing and dissolving the above-mentioned essential components and optional components by a conventional method.

Further, when the cleaning agent of the present invention is used,
The coating film of the protective coating can be removed by applying a diluted solution diluted twice to the coating film of the protective coating and then washing with water.

〔Example〕

Next, the present invention will be specifically described by showing Examples and Comparative Examples. However, the following examples and comparative examples do not limit the present invention in any way.

Table 1 shows the compositions of Examples and Comparative Examples of the present invention. In addition, the numerical value regarding a composition shows a weight part.

(Performance Test) In order to clarify the performance of the cleaning agent of the present invention, the following performance test was conducted with a sample solution prepared by diluting the composition of Table 1 with water.

The test items and test conditions are described below, and the results are shown in Table 2.

(1) Paint resistance A Dip a vertical half of a coated plate (100 x 300 mm) in a cleaning agent at 50 ° C.
After being kept for 60 minutes at 80 ° C., it is washed with water, air-dried, and then immersed in pure water at 40 ° C. for 240 hours. The coated plate was pulled up, washed with water and air-dried, and the coated surface states of the immersed portion and the non-immersed portion were observed and compared.

The evaluation is expressed according to the following criteria.

◎: No abnormality on the coated surface ○: There is a slight hue difference at the boundary between the immersed surface and the non-immersed surface ×: Paint film surface defects such as discoloration, swelling, loss of gloss and softening As for the coated plate, a thermosetting acrylic enamel (black), which is a topcoat paint generally used in the automobile industry, is applied to a chemical conversion treated steel plate so that the dry film thickness becomes 30 to 50 μm, and the temperature is 140 ° C. A coated plate baked for 30 minutes was used.

(2) Paint resistance B The same paint plate as paint resistance A was coated with a protective paint to a thickness of 10 to 20 μm and exposed outdoors in Okinawa for 4 months in the summer. And tested in the same manner. The portion not soaked in the cleaning agent for removal was evaluated by immersing it in isopropyl alcohol at 40 ° C for 5 minutes to remove the protective coating.

As the protective coating material, a coating material which is a water-soluble alkaline resin and is said to have good dry film water resistance, that is, a composition obtained by polymerizing the following is used.

○ Mixing ratio of water-soluble acrylic resin protective paint Butymethacrylate 8.0 parts by weight Methyl acrylate 5.0 parts by weight Methyl acrylate 4.0 parts by weight Acrylic acid 3.0 parts by weight Isopropyl alcohol 3.4 parts by weight Concentrated aqueous ammonia 1.0 parts by weight Lauryl mercaptan 0.5 parts by weight Acid sulfurous acid Sodium 0.1 part by weight Water 75.0 parts by weight (3) Paintability for parts ABS acrylic resin lacquer paint (silver metallic), which is conventionally applied to automobile parts made of ABS resin, is applied to ABS resin plate to a dry film thickness of 10 to 20 μm. To 60 ° C
The test plate dried for 30 minutes in the same manner was tested in the same manner as Paintability A.

(4) Removability A On the same coated plate as for paintability A, the water-soluble acrylic resin-based protective paint used in the test for paintability B was applied, and the coated plate dried at 80 ° C for 24 hours was used as a test piece. After impregnating the sponge with the cleaning agent and gently rubbing the surface of the protective coating 5 times, 2
Let stand for a minute.

Then, the state of removal of the protective coating film after washing with tap water and air drying was observed and evaluated.

The evaluation is expressed according to the following criteria.

◎: The protective paint film was completely removed. ○: The protective paint film was slightly left. △: The protective paint film was thin and remained considerably. ×: The protective paint film was hardly removed. (5) Removability B Similar to Removability B, a paint plate coated with a protective coating that was exposed outdoors in Okinawa for 4 months in the summer was subjected to a removability test in the same manner as Removability A as a test piece.

(6) Removal workability A water-soluble acrylic resin-based protective paint used in the paint resistance B test was applied to a 1,800 cc class car with dark blue metallic coating so that the dry film thickness would be 10 to 20 μm, and then outdoors. After a 1-month exposure to water, 4 liters of the water-diluted solution of the cleaning agent of the present invention was evenly applied with a watering can, and after 2 minutes, the surface of the protective coating film was rubbed with a sponge soaked with the remaining cleaning agent, then tap water 15
It was washed with 0 l of water. The time required for this removal work was examined, and it was described according to the following criteria.

A: The protective agent was completely removed within 20 minutes of working time.

◯: The protective agent was completely removed within 30 minutes of working time.

Δ: Part of the protective agent could not be removed within the working time of 30 minutes.

X: A considerable portion of the protective agent remained after the working time of 30 minutes or more.

(7) Effluent processability of removed effluent Removed effluent (diluting detergent + rinsing water) generated in the removal work was collected, and the effluent was treated according to the following procedure, and the transparency and COD of the treated water were measured.

[Procedure for wastewater treatment]

 B. pH adjustment: Adjust the pH to 7 with 20% sulfuric acid. Addition of flocculant: A sulfuric acid band was added to adjust its concentration to 2,000 ppm.

C. pH adjustment: Adjust pH to 6-8 with 20% sodium carbonate d. Addition of flocculant: A polymer flocculation aid “Himoloc AP107” was added to adjust its concentration to 2 ppm.

In addition, JIS K0102-9 and JIS K0 are used to measure the transparency and COD.
According to 102-17.

(8) Odor The odor of the remover during the removal work was evaluated.

○: No odor problem, △: Odor, ×: Strong odor and problems in work It can be understood from Table 2 that the composition of the comparative example has a poor removability B.

〔The invention's effect〕

 The cleaning agent of the present invention has the following effects.

(1) It exerts excellent cleaning performance even on a coating film that has been applied for a long period of time after being applied with a protective coating for outer panels of automobiles and the like.

(2) There is no risk of ignition.

(3) It is safe for the human body.

(4) There is no problem in wastewater treatment.

(5) It becomes possible to improve the efficiency of the removal work.

Claims (6)

[Claims] 1. A water-soluble amine, (B) an aliphatic polyhydric alcohol derivative or an aliphatic saturated monohydric alcohol having 1 to 3 carbon atoms, (C) a sequestering agent, and (D) ) A cleaning agent for removing a protective coating, which is composed of water. 2. (A) Content of water-soluble amine is 10 to 30 parts by weight, (B) Content of aliphatic polyhydric alcohol derivative or saturated aliphatic monohydric alcohol having 1 to 3 carbon atoms The amount of 3 to 15 parts by weight, (C) the content of the sequestering agent is 1 to 10 parts by weight, and (D) the content of water is 45 to 86 parts by weight. A cleaning agent for removing the protective coating film described. 3. The method according to claim 1, wherein a part of the water-soluble amine is replaced with one or more selected from concentrated aqueous ammonia, potassium hydroxide, sodium hydroxide and silicate. Cleaning agent for removing protective coatings. 4. (A) Water-soluble amine, (B) Aliphatic polyhydric alcohol derivative or saturated aliphatic monohydric alcohol having 1 to 3 carbon atoms, (C) Sequestering agent, (D) ) A cleaning agent for removing a protective coating film, which comprises water and (E) an anionic surfactant or a nonionic surfactant. 5. The cleaning agent for removing a protective coating film according to claim 4, wherein the content of the anionic surfactant or the nonionic surfactant is 0.1 to 5 parts by weight. 6. The method according to claim 4, wherein a part of the water-soluble amine is replaced with one or more selected from concentrated aqueous ammonia, potassium hydroxide, sodium hydroxide and silicate. Cleaning agent for removing protective coatings.