JPH05125570A - Method for washing and drying metallic work piece - Google Patents

Abstract

PURPOSE:To efficiently wash and dry a metallic work piece without impairing the coatability of this metallic work piece by immersing the metallic work piece after washing into an aq. soln. of a anionic fluorine surfactant and rinsing the metallic work piece with water, then drying the body. CONSTITUTION:The washing and drying of the metallic work piece entailing surface treatments, such as coating of a rust preventive oil and rust inhibitor, and painting, are executed. After the metallic work piece is washed, the metallic work piece is immersed into the aq. soln. of the anionic fluorine surfactant. The body is then rinsed with the water and is dried. A compd. contg. a polyfluoroalkyl group is used for the anionic fluorine surfactant. As a result, the washing and drying which are efficient even by washing with the water are executed without using a chlorinated org. solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of drying a metal working body in a washing step, and particularly, in the case where a surface treatment such as coating or coating with rust preventive oil or rust preventive agent is carried out as a subsequent step, the coatability and the coating property are improved. The present invention relates to a novel washing and drying method that can efficiently dry without impairing the property.

[0002]

2. Description of the Related Art Conventionally, a chlorine-based organic solvent such as 1,1,1-trichloroethane has been used for cleaning a metal surface before or after metal processing. However, in recent years, the use of chlorine-based organic solvents has been regulated for the purpose of protecting the global environment.
Aqueous cleaning is considered as an alternative cleaning method,
In the case of water-based cleaning, hot air drying is required as a drying method, a large-sized drying apparatus is required, and a large amount of energy is required to generate hot air, which is expected to accelerate global warming.

On the other hand, as a method for removing water from the surface of a steel strip after cleaning the steel strip with an acid, a method using a fluorine-containing surfactant has been proposed in Japanese Patent Laid-Open No. 57-198272.

[0004]

The method of using a fluorine-based surfactant as a draining agent for a metal surface gives good results as long as it has draining ability, and is an excellent method from the viewpoint of efficient drying. I can say. However, when this method is used, when applied to a metalworked body that is subjected to surface treatment such as rust preventive oil and rust preventive agent coating or painting as a post-process, cissing may occur due to the water and oil repellency of fluorine. However, it has not been put to practical use due to the problems that it occurs or the adhesiveness is poor.

[0005]

Means for Solving the Problems The present invention has been completed based on various studies and researches for solving the above-mentioned problems, and is applied to surfaces such as coating and painting of rust preventive oil and rust preventive agent. In the method for washing and drying a metalworked body accompanied with treatment, after washing the metalworked body, the metalworked body is immersed in an aqueous solution of an anionic fluorosurfactant, and then rinsed with water and dried. The present invention newly provides a method for washing and drying a metalworked body characterized by:

In the present invention, it is important to use an aqueous solution of an anionic fluorosurfactant. In the case of nonionic fluorosurfactants, drainage performance is poor due to insufficient adsorption on the metal surface, or surface treatment such as coating and painting of rust preventive oil and rust preventive agent is performed as a post-process after draining and drying. In this case, there are some difficulties in coating and painting.

Examples of suitable anionic fluorochemical surfactants include surfactants composed of compounds containing a polyfluoroalkyl group having 4 to 20 carbon atoms, preferably 6 to 18 carbon atoms. The polyfluoroalkyl group may be linear or branched, and may partially contain a hydrogen atom or a chlorine atom, or may have an ether bond, but a terminal having a perfluoroalkyl structure is particularly desirable.

In order to further improve the water draining performance and the coating / coating property in the subsequent step, at least one hydrocarbon group selected from the group consisting of an alkyl group, a methylene group, a phenyl group and a phenylene group together with a polyfluoroalkyl group. An anionic fluorosurfactant composed of a compound also containing can be exemplified. For example, an anionic fluorosurfactant composed of a compound in which a polyfluoroalkyl group and an anionic group are linked by a methylene group and / or a phenylene group can be mentioned. Further, as the anionic group, a carboxyl group or a phosphoric acid group is desirable.

Specific examples of the anionic fluorosurfactant include C _n F _{2n + 1} (CH ₂ ) _m COONH ₄ C _n F _{2n + 1} CONH (CH ₂ ) _m COONH ₄ C _n F _{2n + 1} SO ₂ NH (CH ₂ ) _m COONH ₄ C _n F _{2n + 1} CONR ¹ (CH ₂ ) _m COONa C _n F _{2n + 1} SO ₂ NR ¹ (CH ₂ ) _m COONa C _n F _{2n + 1} OC ₆ H ₄ COONH ₄ C _n F _{2n + 1} C ₂ H ₄ OPO (O ・ NH ₄ ) ₂ (C _n F _{2n + 1} C ₂ H ₄ O) ₂ PO ・ ONH (C ₂ H ₄ OH) ₂ C _n F _{2n + 1} C ₂ H ₄ OC ₂ H ₄ COONH ₄ C _n F _{2n + 1} CONHC ₆ H ₄ COONH ₄ (However, R ¹ is an alkyl group having 1 to 20 carbon atoms or a phenyl group, and n is an integer of 4 to 20. And m is 1-20,
It is preferably an integer of 1-10. ) Etc. can be illustrated.

In the present invention, a cationic fluorosurfactant or an amphoteric fluorosurfactant is used as long as it does not impair the water-removing effect of the anionic fluorosurfactant as described above and the coating and coating properties in the subsequent steps. You may use together an agent, and also a hydrocarbon type surfactant.

As the cationic fluorosurfactant which can be used in combination, C _n F _{2n + 1} CONH (CH ₂ ) ₃ N (CH ₃ ) ₃ IC _n F _{2n + 1} SO ₂ NH (CH ₂ ) ₃ N ( CH _{3) 3} I (Here, n is an integer of 4-20.) or the like may be exemplified.

As the amphoteric fluorochemical surfactant which can be used together, C _n F _{2n + 1} CONH (CH ₂ ) ₃ N (CH ₃ ) ₃ .CH ₂ COOH C _n F _{2n + 1} SO ₂ NH (CH _{2) 3 n (CH 3)} 3 · CH 2 COOH ( where, n is an integer of 4-20.) or the like may be exemplified.

Suitable examples of the hydrocarbon surfactant include anionic, cationic, amphoteric and amine oxide type surfactants. For example, C ₁₈ H ₃₇ COON
a, C ₁₈ H ₃₇ COOK, C ₁₂ H ₂₅ SO ₃ Na, C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₃ COON
a, C ₁₆ H ₃₃ CONH (CH ₂ ) ₃ COOK, C ₈ H ₁₇ OPO (NH ₄ ) ₂ and other anionic compounds, C ₁₂ H ₂₅ N (CH ₃ ) ₃ Cl, C ₁₂ H ₂₅ NH ₂ ( CH ₃ ) Cl,
[C ₁₁ H ₂₃ OCH ₂ N (CH ₃ ) ₃ ] Cl and other cationic compounds, C ₁₂ H
Examples include amphoteric compounds such as ₂₅ N (CH ₃ ) ₂ · CH ₂ COOH, lauryl carboxymethylamino imidazoline salt, and amine oxide compounds such as lauryl dimethyl amine oxide.

The aqueous solution of the anionic fluorosurfactant in the present invention has a surfactant concentration of 100 to 1000 p.
pm may be used. Preferably 300-800pp
It is about m. If the concentration is too high, the drainage performance will not be improved, and the coating / paintability after drying will be impaired. If it is too low, good drainage performance will not be obtained.

Various conditions for dipping the metal processed body in the aqueous solution of the anionic fluorosurfactant as described above are as follows:
Although not particularly limited, the treatment temperature is preferably selected from the range of about 40 to 90 ° C, and particularly preferably about 50 to 70 ° C. If the temperature is too high or too low, poor adsorption of the surfactant to the metal surface is observed, and good drainage performance cannot be obtained. The immersion time and other conditions can be appropriately selected.

In the present invention, the treatment operations other than the above-mentioned dipping treatment, that is, the washing operation of the metal-worked body, the rinsing operation with water, and the drying operation are particularly limited, including the operating conditions. It can be widely adopted without being used. For example, it is preferable to use an aqueous cleaning agent in the cleaning operation, and it is preferable to use pure water in the rinsing operation.Although the drying operation may simply be pulled up from the immersion treatment bath, a rinse using an air knife or the like may be used. You may drain it later.

Further, the cleaning and drying method of the present invention is applied to a metalworked body, but is usually applied to a metalworked body which is usually subjected to a surface treatment such as application of rust preventive oil or rust preventive agent or coating as a post-process. It is preferably applied. Specific examples include metal parts, metal semi-finished products, intermediate products, etc. that require storage for standby or transportation / transportation to the next assembly process. This is because rust preventive oil and rust preventive agent are applied to prevent metal corrosion during storage and transportation. Further, it is suitable for a washing and drying method as a pre-process when coating or the like is performed for finishing a metal product.

Further, the metalworked body is mechanical, electrical,
It can be widely used in various fields such as chemistry, transportation, and medical care, and may be a metal material partially used.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 3 and Comparative Example 1 50 pp of anionic fluorosurfactant shown in Table 1 below.
Prepare 500 ml of an aqueous solution containing m, place it in a beaker, and heat to 60 ° C. A 2 cm square aluminum test piece is washed with an aqueous cleaning agent, rinsed, and then immersed in the above aqueous solution. After that, rinsing treatment was performed by immersing in pure water and pulling it up, and then water adhering was removed with a water draining air knife, and the water draining effect was visually determined.

Next, a commercially available room temperature curing type acrylic paint was applied, and the wettability of the paint and the adhesiveness were evaluated by a cross-cut peeling test.

Criteria for judging the draining effect, wettability, and adhesion are as follows. Excellent ・ ・ ・ ◎ Good ・ ・ ・ ○ No ・ ・ ・ ×

As a comparative example, the same washing, rinsing, and dipping as the above was carried out for the case where an aqueous solution containing 50 ppm of the nonionic fluorine-containing surfactant shown in Table 1 below was used.
A pure water rinse-air knife treatment and three types of determination were performed.

The results are summarized in Table 1 below.

[0025]

[Table 1]

[0026]

The washing and drying method of the present invention, in the case of a metal processed body which is subjected to a surface treatment such as application of rust preventive oil and rust preventive agent or coating as a post-process, without impairing the coatability and coatability, It has an excellent effect that it can be efficiently washed and dried. Further, according to the method of the present invention, it is possible to perform efficient cleaning and drying by water-based cleaning without using a chlorine-based organic solvent, and because hot air drying is unnecessary, it is extremely effective from the viewpoint of global environment conservation. Is.

Claims (6)

[Claims] 1. A method for washing and drying a metalworked body, which comprises surface treatment such as application of rust-preventive oil or rustproofing agent or coating, and after washing the metalworked body, the metalworked body is treated with an anionic fluorine-based interface. Immerse in an aqueous solution of activator, then rinse with water,
A method of washing and drying a metalwork, which comprises drying. 2. The method for washing and drying according to claim 1, wherein the anionic fluorochemical surfactant comprises a compound containing a polyfluoroalkyl group. 3. An anionic fluorosurfactant comprising a compound containing at least one hydrocarbon group selected from the group consisting of an alkyl group, a methylene group, a phenyl group and a phenylene group. How to wash and dry. 4. The method for washing and drying according to claim 1, wherein the anionic fluorochemical surfactant comprises a compound containing a carboxyl group or a phosphoric acid group. 5. The washing and drying method according to claim 1, wherein the washing is washing with an aqueous detergent. 6. The rinse according to claim 1, wherein the rinse is pure water.
The method of washing and drying according to any one of 5 to 5.