JPS60114587A - Acidic galvanizing method - Google Patents

Abstract

PURPOSE:To form a fine film by galvanization without using NH4<+> ions, acetate ions or boric acid which causes a problem during the treatment of waste water by using an acidic galvanizing soln. contg. prescribed amounts of zinc ions, chlorine ions and aminocarboxylic acid or its salt. CONSTITUTION:To an acidic galvanizing soln. contg. >=10g/l zinc ions and >=50g/l chlorine ions is added >=10g/l aminocarboxylic acid or its salt, and galvanization is carried out using the resulting galvanizing soln. Though NH4<+> ions, acetate ions and boric acid are not present at all, satisfactory pH buffering action is produced. The uniformity of a formed film is made higher, and even a part exposed to high current density is hardly burned. Accordingly, a fine film is formed by galvanization.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plating method using an 11♂ curved lead plating solution that does not contain ammonium ions, acetate ions, or boric acid.

Traditionally, resistance + l using zinc chloride and zinc sulfate as zinc sources
lj lead plating lff is widely used, but the acidic zinc plating solution made by Ioki usually contains ammonium chloride, nl,
Contains 1+ buffering agents such as - or sodium or boric acid.

However, conventional plating solutions of this type have problems such as increasing the PI (PI) during wastewater treatment, causing ammonium ions and acetate ions in the plating solution to form complex salts with zinc, etc. Also, it is good for wastewater treatment.
It's not right. Also, boric acid, like 1iIJ, has problems in wastewater treatment. However, acidic zinc plating solutions that do not contain these kings of ammonium ions, acetate ions, and boric acid in their four parts do not have a P11-reducing effect, and may complicate the plating film or cause burns in high current density areas. This causes plating defects such as 9. For this reason, acidic I'lF lead plating solutions conventionally contain at least one of VC ammonium ions, acetate ions, and boric acid.

In view of the above circumstances, the present inventors have discovered that a good P1 can be obtained even if none of ammonium ions, acetate ions, and boric acid is impregnated.
As a result of intensive testing of the acid zinc electroplating method, which has a buffering effect, does not cause plating defects, and produces a good acidic zinc plating film, we found that zinc ion 10 ff/
Aminocarboxylic acid or its salt'f! : When plating is performed using a plating solution containing IO%/ or more,
Surprisingly, even in the absence of ammonium ions, acetate ions, and boric acid, it has a good 11II buffering effect, and the plating film is more uniform than when using boron 1412, which means that there is no burning even in the tonic density areas. It was discovered that a good plating layer 11q with a rough appearance can be obtained, and the present invention was developed based on this finding.

That is, aminocarboxylic acids and their salts have traditionally been
Although it was known as an additive for F lead plating solution, the amount added was small, and as mentioned above, it was used in combination with ammonium ion, acetate ion, &lQ i+1. Add to this +t, aminocarboxylic acid or one bean of ammonium ion, (
tj=f Do not use shunimeshiimen at all and use it at a relatively high degree of melting of 10y/1 or more, which will give you a better pHg value reaction and a better plating wave of 1:^. is the inventor's "knowledge."

t) Below, the present invention will be explained in detail.

A=The acidic zinc plating method according to the invention uses zinc ions of 10
ff/ or more, chlorine ion 50 y-/ or more,
The method is characterized in that the object to be plated is electroplated using an acidic zinc plating solution containing an aminocarboxylic acid or a salt thereof and not containing ammonium ions, acetate ions, or boric acid.

Here, examples of the supply source of zinc ions constituting the plating solution used in the present invention include zinc chloride, zinc sulfate, and the like. In addition, since acetate ion is not used in the present invention, zinc acetate is not used. As mentioned above, the content of zinc ions in plating solution 1 is 9101 or more, preferably 10 to 801i'%, and preferably 20
~50P.

Further, when zinc chloride is used, chloride ions are supplied from this, but when they are insufficient or when zinc chloride is not used, they can be supplied using potassium chloride, sodium chloride, etc. Its content is 50.7- or more per plating solution, but preferably 50.7- or more.
0~30oy-1 tlf tlf i or 100~
It is 2001.

The plating solution of the present invention further contains aminocardoic acid or its salt, and as described above, J plating can be performed without containing ammonium ions, acetate ions, or boric acid. .

In this case, examples of the aminocarboxylic acid include glycine, alanine, serine, cysteine, glutamic acid, lysone, tyrosine, tryptophan, β-alanine, aminotinol, etc., and alanine and glutamic acid are particularly preferably used. In addition, sodium salts of these aminocarboxylic acids and the like are used as aminocardone mm.

In addition, in the present invention, aminocarboxylic acids and their salts may be used in one building alone or in combination in two or more buildings.

As mentioned above, the content of aminocarboxylic acid and its salts in plating solution 1 is 9101 or more, preferably 10 to 10.
501, preferably 15-307. If the blending amount of aminocarboxylic acids is 1oy7 or more, the above-mentioned object of the present invention can be reliably achieved.
If it is less than P/l, the buffering effect will be reduced, the resulting plating film will become rough, and the high current density portions will be prone to burning, making it impossible to achieve the object of the present invention.

In addition to the above-mentioned components, additives such as brighteners and leveling agents can be added to the plating solution used in the present invention, if necessary. As additives such as brighteners and leveling agents, those used in conventional acidic zinc plating solutions can be used without restriction, but in particular, polyamine compounds, polyether nonionic activators, aromatic carboxylates, At least one compound having a C=0 group (aldehyde, ketone),
It is preferable to add all of them, thereby ensuring that the properties of plating film breakage from the plating solution of the present invention that does not contain ammonium ions, acetate ions, and boric acid are improved. It is possible to more reliably create a uniform and smooth deposition state in all parts from the current density part to the low current density part, and to reduce the occurrence of burns in the high current density part.
It can prevent serious injuries.

In addition to these additives, it is also effective to add at least one of sulfonate-based anion activators, carboquine-based or imidacillin-based amphoteric activators, and this will improve the precipitation state in high current density areas. Can be improved throughout history.

Here, 7? Examples of lyamine compounds include polyethyleneimine, 21-tally modified tyreneimine derivatives, fat by
11 combination of amine and epichlorohydrin, ethoxylation and biliamine compound! F=+, known ones such as ethylene oxide adducts of aliphatic amines (Japanese Patent Publication No. 53-1798
0. JP-A-53-80334, JP-A-56-1 f)
9789, '+'Fl'ii 1982-102589,
U.S. Patent No. 4.100. (+ 40. 4th, 146th, 4th
(Refer to Publication No. 41) is mentioned, Z, but L Samurai, I? Polyethyleneimine, especially one with a molecular weight of 500 to 3000, is preferably used, and its addition Plj, tJ: Q, 0
It is preferable to set it to 5 to 10 P/l, especially 0.5 to 35 LA.

In addition, as a polyether nonionic activator, (11
R-0-(C)I2CH20) nH (Rt: Lu or alkyl group with carbon number] ~ 2o, n = 5-60) (
R is H or an alkyl group having 1 to 2 carbon atoms, n = 5 to
60) (n = 10-70) (4) Polyoxyethylene polypropylene glycol block polymer (ppc: molecular weight 500-3000. EO content 30
~80 wt%) (5) Polyoxyethylene polyhydric alcohol aliphatic ester 0.5-20 E/ll, preferably 2-8 M
It is preferable to set it to 1.

Next, as aromatic carboxylates, benzoate and salutyl 5! salt, m,p-chlorobenzoate, 2.4-dichlorobenzoate, cinnamate, etc., and the amount added is 0 to 101/l, particularly 0.05 to 10.11 I/l.
, X is preferably 0.5 to 211/11.

Furthermore, compounds having a C=0 group (aldehydes).

Examples of ketones include aromatic carbinyl compounds such as benzylidene acetone, cinnamic aldehyde, chlorobenzaldehyde, dichlorobenzaldehyde, and furfural acetone, and isobutyl methane, I//13. x
Recommendation"l L, < itO, 005~0.21/l
It is preferable to toss.

In addition, as sulfonate-based anionic surfactants, carboquine-based or imidacillin-based amphoteric surfactants, examples of sulfonate-based anionic surfactants include sialgyl sulfonic acid [, alkylnaphthalene sulfone R91M
, naphthalene sulfonate polymerine condensate, N, N-
Examples include trimethyl-N-alkyl-N-carg, (, sialgylene ammonium petaine, 2-alkyl-1-hydroxyethyl-1-caru-gisimethylimidazolinium salt, etc.), and sulfonate-based anion activators. The amount of the amphoteric activator added should be O to 5 g/l, particularly (1.05 to 51/l, more preferably 0.2 to 0.5 g/l).

Particularly 005 to 59/l, more preferably 0.5 to 1.
It is preferable to set it as 09/l.

Note that 1) of the plating solution used in the present invention! I is 2.5-6
．． 5, particularly preferably 4.5 to 5.5.

When plating is performed using the above-mentioned plating solution, there are no restrictions on the type of object to be plated, and zinc plating is performed after performing an appropriate pretreatment J111. In this case, the plating conditions can be changed in various ways, but the plating temperature is usually 15 to 4
0°C, especially 20-35°C, cathode current density 0.1-5
A/dm", especially the conditions of 0.5-3 A7'dm2 are adopted. Stirring of the plating solution is not necessarily required, but
A cathode rocker, air agitation, etc. may be employed. Further, it is preferable to use sacrificial lead for the anode plate. Note that the plating time is appropriately selected depending on the desired plating film thickness.

Furthermore, the plating method of the present invention can also be carried out by employing a barrel plating method.

Plating removal, chromate treatment if necessary, and other post-treatments P11 can be performed.

The plating film obtained by the method of the present invention has a uniform and smooth appearance, and the chromate film has good layer density. Since the method does not contain any of the following, one-shot water treatment can be easily carried out, and it is suitably employed in place of the conventional acidic curved plating method that contains ammonium ions, acetate ions, and boric acid.

EXAMPLES Hereinafter, the present invention will be explained in more detail by showing Examples and Comparative Examples.

[Example 1, Comparative Example] The following composition ZnC4270'/1 1 (C1220tt - ξton 2') Aluminocarboxylic acid/salt Amount rJl shown in Table 1 5.
A 0% acidic zinc plating solution was prepared, and its buffering effect and appearance of the plating film were examined using a Hull cell tester.

For comparison, sodium acetate was added at 30 f! instead of the aminocarboxylic acid/salt. /l of the liquid used and boric acid at 30
g/l of the liquid used and the following composition Z nCL2 70
Similar experiments were conducted using solutions of NH4 (J 200 // Peptone 2 〃 PH5,0).

-Buffer effect A Hull cell test was conducted using a degreased and pickled 10 cln

Appearance of the plating film A degreased and pickled 10 crn x 7 cIn polished steel plate was used as a cathode, and a Hull cell test was conducted at a current of 2 A for 10 minutes to evaluate the appearance of the resulting plating film.

The results are shown in Table 1.

Table 1* -1 fluctuation range 0.1~0.3:0 0.3~0.6:Δ 0.6~09: × [Example 2] ZnC/-z 100 1/11 KC1220# Alania 15 1 C42H25-〇-(CH2CH20)15H61 Sodium benzoate 2N Benzylidene acetone 0゜38# pi (5,2 Plating temperature 25℃ Dk Two-person plating time 10 minutes When a 1 dm2 pentocathode was plated with the above composition and conditions, A galvanized film with little pH fluctuation and good appearance was obtained.

Applicant: Uemura Kobo Co., Ltd. Agent: Patent Attorney Takashi Kojima

Claims (1)

[Claims] 1,! lli, lead ion 10 t/ or more, chlorine ion 5 (l f/ or more, aminocarboxylic acid or its salt toy, 'z or more), ammonium ion and vinegar nρ ion\1 An acidic zinc plating method characterized by electroplating an object to be plated using acidic zinc plating that does not contain boric acid.