JPH0568551B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to post-treatment of steel plates for soldering, and improves solder spread, solder strength (hereinafter abbreviated as solderability), corrosion resistance,
This invention relates to a post-processing method that has excellent processability, anti-fingerprint properties, and durability over time. [Prior art] In recent years, as solderable steel sheets, Sn-plated steel sheets, PB-Sn-plated steel sheets, Cu-plated steel sheets, and Zn-plated steel sheets have been developed.
Plated steel plate is used. When these plated steel sheets are exposed to the environment in which they are used after being plated, the appearance (color) of the plating changes and rust occurs. Therefore, in order to improve corrosion resistance, chemical conversion treatments such as chromate treatment and phosphate treatment, or temporary application of rust preventive agents, etc., are performed. In the case of chromate treatment, in order to improve corrosion resistance, 0.1 mg/dm ² or more of Cr is required, but chromate treatment significantly reduces solderability, and if it exceeds 0.05 mg/dm ² , it becomes corrosive. It will be a practical problem if a strong flux is not used during soldering. If a highly corrosive flux is used, the environment during soldering work will be poor and the corrosion resistance of the soldered portion will be significantly reduced. Therefore, Cr is 0.05
mg/dm ² or less, and sufficient corrosion resistance cannot be obtained. Further, in the method of temporarily applying a rust preventive agent, the solderability may be reduced as in the case of chromate treatment. In addition, the plated steel plate for soldering is easily contaminated with fingerprints and the like during handling during forming and soldering, and the corrosion resistance of the stained portion after soldering is significantly poor. [Problems to be Solved by the Invention] As mentioned above, in order to obtain a soldering steel plate with excellent properties, post-treatment after plating is required to improve corrosion resistance without damaging the solderability of the plated steel plate. is necessary. However, with known post-processing methods,
Since improvements in solderability and corrosion resistance tend to contradict each other, it is difficult to obtain a steel plate with excellent corrosion resistance and solderability. This tendency becomes more noticeable as the plated steel sheet ages. In other words, it is thought that the cause is that an oxide film grows on the plating surface over time, making it difficult to wet the solder. Therefore, there is a need for improved post-processing after plating. As an improvement measure, Patent Application No. 61-233323 and Patent Application No. 61
-261809 and Japanese Patent Application No. 62-56474, these solder-plated steel plates exhibit significantly superior properties by post-treatment, but the stain resistance during handling and the corrosion resistance of the parts were insufficient. [Means for solving the problem] The post-treatment liquid after plating of the present invention has the following (A), (B),
2 to 200 g of one or more of (C) / (A): water-soluble or water-dispersible abietic acid, benzoic acid, glycerin, C ₁₂ to C ₂₄ saturated fatty acids,
_C18 unsaturated fatty acids, diols, polyethylene glycols, fatty acid glycerin esters, benzotriazole derivatives, paraffin waxes, and one or more of the above metal salts, ammonium salts, and amine salts. (B): Water-soluble or water-dispersible fatty acid higher alcohols, alkylphenols, fatty acids condensed with ethylene oxide, polyethylene glycol/alkylamines, ester bonds of sorbitan and fatty acids, polypropylene One or more types of glycol groups as hydrophobic groups and polyethylene glycol groups as hydrophilic groups, ester bonds of fatty acids and sucrose, lanolin alcohols, and saponified lanolin fatty acids. (C): One or more water-soluble or water-dispersible phosphate ester salts. 2 to 100 g of one or more water-soluble or water-dispersible fluorine-based organic compounds are added to the soap, or 0.01 to 3 g of Cr ⁶⁺ ions and 10 to 100 g of organic amine soap are added alone or in combination. The dry thickness of the processing solution with pH 3 to 10 added is 0.01.
It is characterized by a coating of ~2 μm. The present invention will be explained in detail below. In the present invention, the main component (A) of the solder flux that does not contain water-soluble or water-dispersible halogen ions is organic acids such as abietic acid, benzoic acid, C ₁₂ to _{C 24} saturated fatty acids, and C 24 saturated fatty acids. Contains ₁₈ unsaturated fatty acids such as stearic acid, lauric acid, palmitic acid, and oleic acid. The organic alcohol or fatty acid ester includes glycerin, diol, polyethylene glycol, and fatty acid glycerin ester. Benzotriazole derivatives include benzotriazole, azimidole, 1-N benzoylbenzotriazole, and the like. Waxes include so-called paraffin waxes with a molecular weight of 300 to 500, which are mainly composed of linear saturated hydrocarbons having 20 to 36 carbon atoms. (B) includes water-soluble or water-dispersible aliphatic higher alcohols, alkylphenols, and fatty acids condensed with ethylene oxide, including polyethylene glycol alkyl phenyl ether, polyethylene glycol alkyl ether, Contains polyethylene glycol fatty acid ester. Polyethylene glycol alkylamines include N-polyethylene glycol alkylamine and polyethylene glycol alkylamine ether. For the ester bond between sorbitan and aliphatic, sorbitan fatty acid ester,
Contains polyethylene glycol sorbitan fatty acid ester. Polymers having a polypropylene glycol group as a hydrophobic group and a polyethylene glycol group as a hydrophilic group include polypropylene glycol polyethylene glycol ether. Amide-bonded fatty acids and diethanolamine include fatty acid diethanolamide.
The ester bond between fatty acid and sucrose includes sucrose fatty acid ester. Saponified versions of lanolin alcohol and lanolin fatty acids include polyoxyethylene lanolin alcohol ether and polyoxyethylene lanolin fatty acid ester. Water-soluble and water-dispersible phosphate ester salts of (C) include monobasic or dibasic acid forms with one or two alkyl groups, or soaps with organic amines. . In addition, if the alkyl group is large and is insoluble in water, it can be used by making it an alkali group or by adding ethylene oxide or the like to increase its hydrophilicity. The concentration is preferably 2 to 200 g of the above-mentioned one or more. The effects of the present invention are controlled by the amount of post-treatment liquid applied to the surface of the plated steel plate, and are not limited to the concentration, but the above-mentioned concentration is preferable for handling the treatment liquid. If it contains halogen ions, the corrosion resistance will be significantly reduced, which is not preferable. Next, water-soluble and water-dispersible fluorine-based organic compounds contain perfluoroalkyl groups and have the general formula
When C _o F _2o+1 R ₁ R ₂ , R ₁ includes a methylene group and an ethylene group, and other resin systems may also be used. R ₂ is something that facilitates water solubility or water dispersibility, and includes acrylic esters, methacrylic esters, phosphoric esters, carboxylic esters, and ethylene oxide adducts. Emulsifiers, surfactants, and organic solvents may also be added for the same purpose. Further, some of the F in the perfluoroalkyl group may be replaced by H. n is preferably 3 to 30. When n is 3 or less, the anti-fingerprint property is poor, and when n is 30 or more, the solderability tends to be poor. The concentration of the fluorine-based organic compound is preferably 2 to 100 g/. If it is less than 2g/, no effect on fingerprint resistance is observed, and if it is more than 100g/, solderability tends to decrease. Cr ⁶⁺ is used to stabilize the treatment solution or to improve the corrosion resistance and scratch resistance of galvanized steel sheets.
Add ionic or organic amine soaps alone or in combination. 3g/Cr ⁶⁺ ion
If it is more than that, the solderability will be extremely deteriorated, which is not preferable. Organic amine soaps include dodecylamine,
They include oleoyl imidazoline, aminopropyl tallow amine, and rosin amine, and amines can be used by forming salts with carboxylic acids. If the concentration exceeds 100 g/g, it is effective for corrosion resistance, but it is not preferable because it impairs solderability. In addition, known water-soluble or water-dispersible rust preventive agents may be added. However, in this case, care must be taken in the amount added since some of them reduce solderability. For example, adding an acrylic emulsion improves scratch resistance, but reduces solderability. The appropriate pH of the treatment liquid is in the range of 3 to 10. When it is less than 3, the stability of the treatment liquid is poor, and when it is more than 10, the drying properties of the treated film are poor. The temperature of the treatment liquid is not particularly limited, but if it exceeds 80°C, it may gel and deteriorate the stability of the treatment liquid, so a temperature of 20 to 40°C is usually economical. The coating method is not limited to roll coating, knife coating, roll squeezing after dipping, or air knife squeezing. Drying is not a particular problem as long as it is not sticky to the touch, but if moisture remains, it is undesirable because it can cause rust over time. The dry thickness of the post-treated film is suitably 0.01 to 2 μm. If the thickness is 0.01 μm or less, no effect on the characteristics is observed. When the thickness is 2 μm or more, corrosion resistance tends to improve, but solderability becomes saturated and workability becomes worse, which is not preferable. [Function] The processing solution of the present invention can be used for Sn plating, Pb-Sn plating,
When applied to Cu-plated, Zn-plated or Zn alloy-plated steel sheets, or coated steel sheets thereof, not only improved solderability but also markedly improved fingerprint resistance and corrosion resistance can be obtained. Furthermore, the solderability and corrosion resistance of the plated steel plate after aging are also excellent. The steel plate to be coated is not limited to the above-mentioned plated steel plate. The reason why the properties are improved in this way is not clear, but the formation of oxides, hydroxides, and carbonates on the plated surface is suppressed by the hydrophobic post-treatment of the present invention. In the present invention, the metal compounds formed on the plated surface of the plated steel plate over time are dissolved by the heating of the solder path, and some of them are reduced, so that solder wetting and It is thought that diffusion is promoted and solderability is improved. Further, it is thought that due to the above-mentioned phenomenon, the coating film of the present invention uniformly covers the plated surface, thereby improving corrosion resistance. The present invention has been made based on this knowledge, and by uniformly coating the surface of the plated steel plate with the treatment solution of the present invention, a plated steel plate for soldering is provided which has excellent solderability, anti-fingerprint properties, and corrosion resistance. It is characterized by being able to produce continuously. [Example] Hereinafter, the effects of the present invention will be explained with reference to Examples. Example 1 As a plated original plate, a cold rolled steel plate with a thickness of 0.5 mm was pretreated by conventional degreasing and pickling, and immediately after washing with water, it was heated in a sulfuric acid bath with electricity so that the plating amount was 5 g/ ^m2 . It was galvanized and treated according to the invention of the present application. In other words, monobasic phosphate ester (Kyoeisha Yushi
Co., Ltd.) 100g/, tetrafluoropropyl methacrylate 10g/ as Cr6 ⁺ ion with _CrO3
A coated test piece with a dry thickness of 2 μm was prepared by applying 0.01 g/treatment liquid and drying at 60°C. In Examples 2 to 10, test pieces were prepared in accordance with Example 1 for the treatment of the present invention. Comparative Example 1 A plated original plate was pretreated in the same manner as in Example 1, electrogalvanized in a sulfuric acid bath to a plating amount of 5 g/m ² , and then subjected to a known chromate treatment. i.e. chromic anhydride 20g/, sulfuric acid
A comparative sample was prepared by immersing it in a bath with a bath composition of 0.05 g/dm for 1 second at a bath temperature of 30° C. so that the amount of chromate was 0.05 mg/dm ² as Cr. Comparative Examples 2 to 10 were also plated by a known method and then subjected to post-treatment. Next, the preparation of the test pieces is summarized in Table 1,
The evaluation of characteristics is summarized in Table 2. As shown in Examples 1 to 10 in Table 2, the treated films of the present invention showed excellent effects in corrosion resistance, solderability, fingerprint resistance, and aging. Comparative example 5
Comparative Examples 1 to 4 were treated with chromate treatment and phosphoric acid treatment as commonly used chemical conversion treatments, and Comparative Examples 6 to 10 were treated with no post-treatment that did not contain fluorine-based organic compounds. This is what I did. In Comparative Examples 1 to 6, those that were found to be effective in terms of corrosion resistance had poor solderability and solder wetting, and showed a tendency to be inferior. Also, over time,

【table】

【table】

【table】

[Table] Characteristic evaluation solder spread; 50 mm on a solder bath kept at 250℃
Hold the x50mm test piece still, and place a weight of 0.4g on top of it.
Folded solder (JISZ 3283,
RH50), and the solder spread area was measured after 5, 10, and 15 seconds. ○: Spreading area 200mm ² or more
×: 50 mm ² or less Soldering strength: Place 20 cores of thin copper wire with a diameter of 0.18 mm on the test piece, solder with a soldering iron using sticky solder (RH50), and turn the copper wire in the opposite direction to the test piece. An attempt was made to forcibly break the specimen by pulling it in parallel, and the condition was evaluated. ○: No destruction ×: Complete destruction and corrosion resistance; Salt spray test according to JIS Z2371 2
A cycle was performed (1 cycle: spraying for 8 hours, stopping for 16 hours) and evaluation was made based on the presence or absence of red rust. ○: No red rust ×: Complete red rust workability: Erichsen overhang (Er = 7 mm) and Dupont impact (1/2″ x 1 Kg x 30 cm) were performed.
The plating adhesion was evaluated using sellotape.
○: No peeling Change over time: At constant temperature and humidity (60℃, RH95% or more),
After 1000 hours, the appearance (discoloration) was observed, and the corrosion resistance and solderability were evaluated using the aforementioned tests.
○: No discoloration ×: Full surface discoloration Fingerprint resistance: Artificial sweat (urea 1g/, sodium pyrophosphate 8g/, lactic acid 4.6g/, acetic acid 5
g/, NaCl7 g/, ethyl alcohol 20
ml/, adjusted to 1 with pure water, PH3.75) 0.5cc
The degree of fingerprint adhesion was evaluated by moistening the finger and pressing it against a plated steel plate. In addition, the appearance of the matted steel plate with fingerprints stained at constant temperature and humidity (60°C, RH 95% or higher) after 500 hours was observed and evaluated based on the degree of discoloration. ○: Almost no fingerprints attached. No discoloration △: Slight fingerprints attached. Slight discoloration ×: Significant fingerprint adhesion,
Overall discoloration The color tone of the surface changed and corrosion resistance also tended to decrease. Comparative Examples 6 to 10 tended to have poor fingerprint resistance. [Effects of the Invention] As shown in Examples 1 to 10 in Tables 1 and 2, the method of the present invention provides excellent corrosion resistance, solderability, fingerprint resistance, workability, and durability over time. I was able to obtain a steel plate.

Claims (1)

[Claims] 1 (Water-soluble or water-dispersible abietic acid,
Benzoic acid, glycerin, _C12 - _C24 saturated fatty acids,
2 to 200 g of _C18 unsaturated fatty acids, diols, polyethylene glycols, fatty acid glycerin esters, benzotriazole derivatives, paraffin waxes, and one or more of the above metal salts, ammonium salts, and amine salts) [(water-soluble Or 2 to 100 of one or more water-dispersible fluorine-based organic compounds.
g/added) or additionally 0.01 Cr ⁶⁺ ions
~3g/, 10-100g/ of organic amine soap
)] PH3
A method for post-processing a solder-plated steel plate, which comprises coating a solder-plated steel plate with a dry thickness of 0.01 to 2 μm using a treatment solution of 1 to 10. 2 Water-soluble or water-acidic aliphatic higher alcohols, alkylphenols, and fatty acids condensed with ethylene oxide, polyethylene glycol/alkylamines, ester bonds of sorbitan and fatty acids, and hydrophobic polypropylene glycol groups. water-soluble or water-dispersible 2-100g/of one or more fluorine-based organic compounds
Addition or additional Cr ⁶⁺ ion 0.01~3g/
1. A method for post-processing a plated steel plate for soldering, characterized in that the plated steel plate is coated with a dry thickness of 0.01-2 μm using a treatment solution having a pH of 3-10 to which 10-100 g of organic amine soap is added alone or in combination. 3. Add 2 to 200 g of one or more water-soluble or water-acidic phosphate ester salts to 2 to 200 g of one or more water-soluble or water-dispersible fluorine-based organic compounds.
100g/additional or additional Cr ⁶⁺ ions
0.01~3g/, 10~100 of organic amine soap
PH with g/added alone or in combination
A method for post-processing a plated steel plate for solder, the method comprising coating a solder-plated steel plate with a dry thickness of 0.01-2 μm using a treatment solution of 3-10.