JPS58151490A - Production of colored metallic plate electroplated with zinc - Google Patents

Abstract

PURPOSE:To obtain a metallic plate electroplated with zinc having dense and beautiful colored layers of dark color without application of heat treatment, by subjecting a metallic plate to composite zinc electroplating then to an anodic electrolyzing treatment in the same bath. CONSTITUTION:A metallic plate is subjected to zinc electroplating in an acidic zinc electroplating bath consisting essentially of Zn added with >=1 kind among water-soluble compds. of Co, Ni, Mo, at 3-50g/l Co, Ni and 0.01-3g/l Mo in terms of metal. In succession, the steel plate is subjected to an anodic electrolyzing treatment of 5-500 coulomb/dm<2> quantity of electricity with the plating plate as anode in the same plating bath. The plated metallic plate is thereafter dipped in an aq. soln. contg. silicic acid, silicate, chromic acid, chromate, etc. according to need, and is dried, whereby 10-400mg/m<2> (expressed in terms of Si) is coated thereon. The zinc electroplated metallic plate having the surfaces colored densely to bluish black - black colors is obtained by the above- mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a colored electrogalvanized metal sheet, and more specifically, the present invention relates to a method for producing a colored electrogalvanized metal sheet, and more specifically, the present invention relates to a method for manufacturing a colored electrogalvanized metal sheet, and more specifically, a method for producing a colored electrogalvanized metal sheet.
o o> A colored electrogalvanized metal plate whose surface is colored blue-black to black by performing composite magnetic galvanizing in a bath containing one or more types of galvanized metal, followed by anodic electrolytic treatment (first treatment) in the same bath. Regarding how to get . The present invention also relates to a method of cathodic electrolysis in a separate bath.

In the past, various attempts have been made to color the zinc surface with dark lines in order to improve its decorative properties, light absorption, heat absorption, and anti-reflection properties. These line coloring methods include, for example, (1) black paint application method, Q) chlorate dipping method, (3) molybdate dipping method, (4) chromic anhydride dipping method, (group sulfide dipping method, (6) There are other methods such as sulfuric acid steel dipping method.

However, the method (1) above is expensive, and cheaper methods do not provide good paint film tightness, and methods (6) to (6) require troublesome management of the treatment bath, making it difficult to treat waste liquid. Problems arose, and it was difficult to obtain a stable dark-colored film in a short period of time.

Therefore, the applicant has proposed that the surface of the plated noodles can be colored very easily by first alloying the zinc plating itself with cobalt and/or nickel and then heating the electroplated product. In order to further improve corrosion resistance and appearance characteristics, the above plating solution J:
We proposed an invention that enables the production of desired colored electrogalvanized products by adding organic additives, performing silicic acid post-treatment on the surface after plating, or applying a synthetic resin paint (special invention). (1993-91993).

However, the heating method still has problems from the standpoint of energy saving, and it is difficult to control the degree of coloring, so uniform coloring cannot always be obtained, and the productivity and corrosion resistance after treatment are slightly inferior, resulting in the occurrence of interpolation points. However, the results of implementation will be clear.

Therefore, the inventor of the present invention was forced to remember the later Banshita, and as a result of various experiments and considerations, mainly by performing 1 degree of unipolar electrolytic treatment (1st treatment) after plating, it was possible to We have discovered that we can solve the Tsumugi problem.

However, as proposed above, it is known that the surface of alloy galvanized noodles containing Co and Ni becomes dark colored by heating, that is, by oxidation, and it is also possible to induce this oxidation phenomenon in a bath by anodic electrolysis treatment. Yu1 et al.

In other words, when the surface of a composite electrogalvanized metal plate is electrolytically treated (first step) in a bath using the surface as an anode, nascent oxygen is generated on the surface of the anode, and the plating layer is slightly redissolved. Because of the oxidation, an oxidation phenomenon similar to that of heating in air occurs, and it is thought that preferential oxidation of Co, Ni, or MO occurs, resulting in coloring4.Moreover, unlike in the case of heating, oxide particles of MO are generated. As a result of experiments, it became clear that an m-dense colored layer could be obtained without the need to see.

An object of the present invention is to provide a method for producing a colored electrogalvanized metal sheet that can provide a dense and beautiful colored layer without heat treatment.

Another object of the present invention is to provide a method for manufacturing galvanized metal sheets that requires extremely short processing time.

According to the present invention, one or more of water-soluble Co, Ni or Mo compounds is added as a metal in an amount of 3 to 5 of/ft1 for Co and Ni.
After electrogalvanizing a metal plate in an acidic electrogalvanizing bath mainly containing Zn added with M0 Nitteha α01~3t/2, the amount of electricity is 5~500 coulomb/d- in the same bath.
A method for producing a colored electrogalvanized metal sheet characterized by subjecting it to an anodic electrolytic treatment (first treatment) of water-soluble Co,
One or more types of Ni or Mo compounds and Co as a metal
, 3~5oφ for Ni, α01 for Mo
~3tli, after electrogalvanizing a metal plate in an acidic electrogalvanizing bath containing added Zn as a main component, anodic electrolytic treatment at an electric current of 5 to 500 coulombs/dwt (first treatment) in the same bath. coloring, followed by cathodic electrolytic treatment (second treatment) with an amount of electricity of 5 to 500 coulombs/dot in a bath containing 5 to 100 t/iL of dichromic acid and/or dichromate. A method of manufacturing an electrogalvanized metal sheet is provided.

The present invention will be explained in detail below.

When a metal plate is electroplated in a zinc-based core containing water-soluble cobalt and/or nickel and/or molybdenum compounds, plating 1- naturally contains cobalt and/or nickel in addition to zinc. and/or M.

is eutectoid. Therefore, when this electrogalvanized gold plate is subjected to anodic electrolysis treatment (first treatment) in a plating solution, one or more of Co, Ni, and Mo present on the zinc surface is preferentially oxidized, resulting in a blue-black to black color. begins to appear on the surface. This phenomenon cannot be overcome by a simple conventional anodic electrolytic treatment of electrogalvanized metal sheets, and the presence of the eutectoid metal that serves as a color former is essential.

The present invention is basically a further improvement of the invention described in the specifications of JP-A-55-91993 and JP-A-56-293. That is, the present invention uses an electroplating solution to subject a plated metal plate to an anodic electrolytic treatment (
The desired effect was achieved for the first time based on the new knowledge that a plated metal plate can always be colored darkly in a short period of time by carrying out the first treatment.

Here, the base metal sheet is a hot-rolled steel sheet from which scale has been removed, a cold-rolled steel sheet, a galvanized steel sheet, a furiki, a tinted steel sheet, a Co
In addition to steel plates such as plated steel plates and stainless steel plates, various nonferrous metal plates such as Cw or Cu alloy plates, All or A1 alloy plates, etc. can be used.

In the present invention, the amount of additive elements and organic additives in the plating bath composition and the anodic electrolyte treatment! The reason why the amount of electricity M (first process) is limited is as follows. That is,
The compound component of cobalt and/or nickel is desirably in the range of 3 to 5 Qtli as a metal, because if it is less than 3, it will be difficult to develop color even if the anodic electrolytic treatment (first treatment @) is carried out, and 59 f This is because if the amount is more than /1, the plating work becomes difficult and the plating performance deteriorates. A particularly desirable component of the cobalt and/or nickel compound is 5 to 20 f/It based on experience as a metal.

Moreover, the compound of MO is 0.0% as a metal. O1~3 tli
A range of is desirable. The reason for this is that below 0.01 tli B, the coloring effect is small, and above 3 t, A, the adhesion of the plating layer decreases.

Furthermore, one way to improve the appearance after color development is to reduce the plating layer itself. That is, by adding organic additives to the plating bath, blue-black or blackening is promoted through anodic electrolytic treatment (first treatment) without post-treatment or painting, thereby obtaining a beautiful colored galvanized metal sheet. It is possible. Of course, it goes without saying that if you apply post-treatment and painting in addition to this, the aesthetic appearance will further increase. Suitable organic additives include water-soluble or water-friendly organic compounds such as polyacrylate copolymers, dicyandiamide formaldehyde, polyvinyl alcohol, or cationic polyamines, and at least 1 of these organic additives are present in the plating bath. If Yuzui E is added in a total amount of 0.1 to 10 t/It, a beautiful glossy surface of deep blue-black to black color can be obtained. The additive filter is ineffective if it is less than a 1 fA, and if it exceeds 10 f/12, the plating properties deteriorate, so the above range is not acceptable.

Further, the anodic electrolytic treatment (first treatment) in the above bath following the eutectoid galvanizing has an electric charge of 5 to 500') -tf
f y%- is desirable. The amount of electricity is 5 y/d
m or less, the coloring effect is small, and 500 coulombs/
If it exceeds ad, problems will arise in the adhesion of the treated film, and it will be uneconomical because the mu will be redissolved in proportion to the amount of electricity used in the anodic treatment.

The bare corrosion resistance of these blue-black or blackened eutectoid electrogalvanized metal sheets is generally good in a weakly corrosive atmosphere (constant temperature and humidity test), but is somewhat unsatisfactory in a salt spray test. For example, in the case of the basis weight I Q f/hl,
In the constant temperature and high humidity test, there was no change at all even after 50 days, which was good, but in the salt spray test, white rust occurred after 38 hours.

In addition, as a means to enhance the beauty of the blue-black or black surface by giving it a deep appearance, and to improve corrosion resistance, there is a method in which the surface is treated with silicic acid after plating and anodic electrolytic treatment (JL!1 treatment), and transparent or Applying semi-transparent synthetic resin coating
[There is a way.

The silicic acid treatment refers to an aqueous solution of silicic acid or a silicate such as lithium silicate, potassium silicate, sodium silicate, or a mixture thereof (if necessary, chromic acid or a chromate or a mixture of chromates or the like is added) to the above-mentioned. It is applied to the blue-black or completely black eutectoid electrogalvanized surface by, for example, dipping, spray painting, roll painting, or other means, and then dried. In this case, the amount of snow deposited (coated film amount) is measured as silicon. 10-40oIIV after drying
%Ir It is important to make the wall cloth as it is. In other words, if the silicone attachment device is less than 10, it is ineffective, and 4
This is because if it exceeds 0.00, the adhesion of the treated film will deteriorate.

In addition to the above-mentioned silicic acid treatment, in addition to silicic acid or silicates, phosphoric acid or phosphates or water-soluble or water-dispersible It can also be obtained by coating an aqueous solution containing organic molecules.

The transparent to semitransparent coating film applied after the -electrode electrolysis treatment (first treatment) can be obtained by diluting various natural or synthetic resins with water or an organic solvent, applying the diluted solution, and drying the coating. These resin paints include, for example, boiled oil, oil varnish, volatile dry varnish, shell varnish, lacquer, phenolic resin varnish, lid # [resin varnish, urea resin varnish,
These include melamine resin varnish, vinyl acetate/acrylic resin varnish, styrenated alkyd, resin varnish, etc. Application methods include dipping, spray coating, roll coating, and others.

When the above-mentioned silicic acid treatment or resin coating is applied, the finished galvanized surface becomes deep blue-black or black, improving the aesthetic appearance and improving corrosion resistance as shown in the examples below.

In addition, cathodic electrolytic treatment in dichromic acid and/or dichromate (1$2
Treatment) is preferably conducted at an electric power of 15 to 500 y7ad. If it is less than 5 coulombs/dwI, the effect of improving corrosion resistance is small, and if it is more than 50 coulombs/dwI, it is not economical.

In addition to these, there is also a method of further applying a L7 transparent or translucent synthetic resin coating without the above-mentioned silicic acid treatment after cathodic electrolytic treatment (second treatment) in a dichromic acid and/or torochromate solution. These processing conditions are preferably within the ranges already described.

As described above, by carrying out the present invention, it is possible to obtain a dark colored galvanized gold plate with no color unevenness through relatively simple processing. In other words, all of the above objectives can be achieved. Therefore, the industrial value of the present invention is significantly large.

It goes without saying that the base metal plate may be any of various processed metal plates or metal products.

Examples are shown below.

Example 1 Plate thickness α4t4) A mild steel plate was electrolytically degreased in a 7% caustic soda aqueous solution and washed with water, then pickled with 70 f/It sulfuric acid and washed with water to obtain a plating original plate. The original plate obtained by the above treatment was plated under the following conditions.

Plating bath composition Zn804-7H20250t/1°(NH4)ri・804 15
t/11CO804・7Hri0 (as CO)
St/It dicyandiamide formaldehyde
1 f/It plating bath temperature 38℃ Current density 25 A/d++/plating amount
10 f/Ml The obtained galvanized copper plate containing Co was then subjected to an electrolytic treatment (first treatment) in the above plating bath with the galvanized steel plate as an anode at an amount of electricity of 40 coulombs/dwl.
00 v/11 lithium silicate solution (Li*O:
After being immersed in 8t (h 1:4) for 3 seconds and dried, the film was roll coated so that the amount of silicon deposited was 200 -, and then dried with a hot dryer.

The obtained sample exhibited a beautiful deep blue-black to black color, and the film did not peel off even in a cellophane tape peeling test. or,
In the salt water spray test according to JIS Z 2371, there was no change at all after 24 continuous hours.

Example 2 A plating original plate that had been degreased and pickled in the same manner as in Example 1 was plated under the following conditions.

Plating bath composition Zn80a/7H20250f/11 (NH4)2801 15 f/11
Ni804・7H20 (as Ni) Bt7t
h polyvinyl alcohol 2
t/j! Plating bath temperature: 50°C Current density: 25 A/dwt Plating amount: 15 f/♂ The obtained galvanized steel sheet containing Ni was subsequently subjected to anodic electrolysis treatment (IJI treatment) at 100 coulombs/ds' in the above bath. was applied, and lithium silicate was further applied in the same manner as in Example 1.

The obtained sample exhibited a beautiful deep blue-black to black color, and there was no peeling of the film in the cellophane tape peeling test, and the JIS
In the salt spray test using Z 2371, there was no change at all after 24 continuous hours.

Example 3 A plating original plate that had been degreased and pickled in the same manner as in Example 1 was plated under the following conditions: Plating bath composition Zn80m4Hs0 250t/11 (
NH4) a80a 15 f
/ILCO804・7HsO (as Co>8
t/jl Plating bath temperature 45℃ Current density 25 A/dm'' plating amount
15 t/ml The obtained galvanized steel sheet containing Co was subsequently subjected to an anodic electrolytic treatment (
1st treatment), and further immersed in a concentration of 500 tA o>Katsukum silicate solution (K: 8i (h-1:4) for 3 seconds, and after drying, the amount of silicon deposited was 200-
After roll coating, it was dried with a hot dryer.

The obtained sample exhibited a beautiful blue-black to black color, and the film did not peel off even in the cellophane tape peel test.
In the salt water spray test using 2371, there was no change at all after 24 continuous hours.

Example 4 In the same manner as in Example 1, a degreased and pickled original plate was plated under the following conditions.

Plating bath composition Zn804・7H20250t/11 (NHa)s80420t/11 CO804・7H20 (as Co) 8f/
i(NH4)6MO7024・4H200, 1 t/L Current density 25 k/dyl Coating amount 20 t/♂ The obtained galvanized steel sheet containing Co and Mo! Subsequently, it was subjected to anodic electrolytic treatment (first treatment) with an electric charge of 200 coulombs/d in the above bath, and then immersed for 3 seconds in a lithium silicate solution containing 5 f/s of Crys at a concentration of 5 oor/n, and after drying. The bulk amount as silicon is 2oo in
After roll-coating it to give the desired color, it was dried with a hot dryer.

The obtained sample exhibited a beautiful deep blue-black to black color, and there was no peeling or separation of the film in the cellophane tape peeling test. Also J
There was no change at all even after 24 hours of continuous salt spray testing using I8Z 2371.

Example 5 A plated base plate for degreasing and pickling was plated under the following conditions in the same manner as in Example 1.

Plating bath composition 1m80a・7H depth 0 250t/11
Ni80a・7HtO (as Ni) 8F/41 (NH
a) Snow 804 15 t/11 Plating bath temperature 40'C Current density 25 people/dWl Plating amount 20 f/Ili! 'Obtained N
A galvanized steel sheet containing i was heated in the above plating bath with an electric charge of 40
It was subjected to an anodic electrolytic treatment (first treatment) at 0 coulombs/dWt, and then a transparent synthetic resin paint (trade name: Kanpekutsuya Lacquer) was spray-coated.

The obtained sample exhibited a beautiful blue-black to black color, and no peeling of the film occurred in the cellophane tape peeling test.

Also, in the JI8 Z 2371 salt spray test, continuous 24
There was no change at all after the passage of time.

Example 6 A plating original plate that had been degreased and pickled in the same manner as in Example 1 was plated under the following conditions.

Plating bath composition Zn8044H20250t/11 (NH4)2804 □51/Jl
Co804・7H20 (as Co) 5
t/1tNi8047HzO (Ni, Te)
5 t/11 dicyandiamide/formaldehyde l f/It plating bath temperature
38°C Current density 25 A/d♂ Coating amount 20 t/Ml The obtained galvanized steel sheet containing Co and Ni was subjected to electric [200 coulomb/U anodic electrolytic treatment (first
treatment), and then heated in a bath containing 30 f4 of sodium dichromate at a temperature of 40°C with an electric current of 11 L, 100 L/d.
The cathode treatment (second treatment) of d was performed, and then lithium silicate was applied in the same manner as in Example 1.

The obtained sample had a beautiful deep blue-black to black color, and there was no peeling of the film in the cellophane tape peeling test, and it was JI8.
Z! In the salt spray test using No. 371, there was no change at all after 24 continuous hours.

Comparative Example 1 A plated original plate for degreasing and pickling was plated under the following conditions in the same manner as in Example 1.

Plating bath composition Zwr8044Hi0 250 t7
! -(NHa) 804 15 f
/1 Current density 25 A/dMl Coating amount 10 t/d The obtained galvanized steel sheet containing CO had a gray color, and there was no peeling of the film in the cellophane tape peeling test, but JI8
In the salt water spray test using No. 22371, white-red rust had occurred on the entire surface after 24 hours.

Comparative Example 2 A plated original plate for degreasing and pickling was plated under the following conditions in the same manner as in Example 1.

Plating bath composition Zn8044Hz0 250 fIQ(N
H4) 2804 15 f/IC
0804・7H20 (as Co) B
t7th(NHa)iMoyOz+・4H200,1f
/j! Current density: 25 k/dvt Plating amount: 1 ot/wl The resulting galvanized sheet containing Co and Mo exhibited a glossy pale yellow color, and there was no peeling of the film in the cellophane tape peeling test, but JI8 Z 2371 After 24 hours, white-red rust had formed on the entire surface of the product in a salt spray test conducted by the company.

Comparative Example 3 A plating original plate that had been degreased and pickled in the same manner as in Example 1 was plated under the following conditions.

Plating bath composition Zn80n4Hz0 250t/1(N
H4) i80a 15 fIQ.

Plating temperature 40℃ Current density 25 k/dwl plating amount
20 f/IIF The obtained galvanized copper plate was subjected to anodic electrolytic treatment (first treatment fi) in the above plating bath at an electric charge of 100 coulombs. The obtained sample has a gray color,
There was no peeling of the film in the cellophane tape peeling test, but in the salt spray test according to JI822371, 2
After 4 hours, white-red rust had formed on the entire surface.

The following examples are summarized in Table 1.

Patent applicant: Toyo Kohan Co., Ltd.

Claims (1)

[Claims] (1) One of water-soluble Co, Ni or Mo compounds
3 to 50 for Co and Ni as metals
f/It. For the intestine, after electroplating the metal plate in an acidic electrogalvanizing bath containing Zn as the main component to which 0.01 to 3 t7tt was added, an electric flux of 5 to 500 coulombs/galvanization was applied in the same bath.
A method for producing a colored electrogalvanized metal sheet characterized by a fist subjected to dwl anodic electrolysis treatment (first treatment). (i) The acidic magnetic galvanizing bath further contains at least one of a water-soluble or water-dispersible organic compound such as a polyacrylate copolymer, dicyandiamide/formaldehyde, polyvinyl alcohol, or a cationic polyamine in a total of 0.1 A method for manufacturing a plated metal plate according to claim 1, wherein the bath contains 10 fA. and/or applying a water bath solution containing chromic acid and/or chromate so that the silicon bonded wire after drying is 10 to 400-4/ll.Claims 1 to 2 O ) C) A method for producing a plated metal plate according to any one of item 1. (4) The above-mentioned anodic electrolytic treatment (first treatment): Washing and drying the slightly stretched table board with water, and then applying a resin paint Y Hotaru 11J to form a transparent or translucent coating film.Claim 1
Q) Manufacturing method 1 of plated metal plate as described in any one of claims 1 to 3, (9) Any one of claims 1 to 4, wherein the metal plate is a copper plate or a non-ferrous metal plate. The method for manufacturing a plated metal plate according to item 1. (6) One type of water-soluble Co, Ni or Mo compound is used as a metal and Co and Ni are 3 to 5097.
M, M (for +, 0.01'-3y/It was added 71>f) After the metal plate was air-bent plated in an acidic electrogalvanizing bath containing 0.01'-3y/It as the main component, magnetic-5 ~
Anodic electrolysis treatment (first treatment) at 500 coulombs/dze is performed, and then dichromic acid and/or dichromate is applied at 5 to 1
Electric flux 5-500 coulombs/d♂ in a bath containing 00 fA
A method for producing a colored electrogalvanized metal sheet, characterized by subjecting it to cathodic electrolytic treatment (second treatment). (Force) The acidic electrogalvanizing bath further contains at least one or more of each organic compound of water-soluble or water-dispersible polyacrylate copolymer, dicyandiamide formaldehyde, polyvinyl alcohol, or cationic polyamine in a total amount of 0.1 to A method for producing a plated metal according to claim 6, which is a bath containing lQ f/n. (6) The plated metal plate after the cathodic electrolytic treatment (second treatment) is further coated with silicic acid and Any of claims 6 to 7, wherein the aqueous solution containing silicate and/or chromic acid and/or chromate is applied so that the amount of silicon deposited after drying is 10 to 400 apAd. The method for producing a plated metal plate according to item 1. ■ A construction patent for producing a transparent or translucent coating film by washing and drying the metal plate after the cathodic electrolytic treatment (second treatment) and then applying a resin paint. A method for manufacturing a plated metal plate according to any one of claims 6 to 8.Claims 6 to 9, wherein the metal plate is a steel plate or various non-ferrous metal plates. A method for producing a plated metal plate as described in any one of the above items for burial mounds.