JPS6199680A - Organic substance coated copper plated steel sheet - Google Patents

Abstract

PURPOSE:To improve the characteristics such as discoloration resistance and fingerprint resistance of a Cu-plated steel sheet by coating a specific resin film directly or via a chromate film on the surface of said steel sheet. CONSTITUTION:The resin of the following compsn. is coated on the Cu-plated steel sheet directly or after the chromate film is formed thereon: 1-95wt% Monomer such as methyl (meth)acrylate expressed by general formula (I), 3-20wt% alpha, beta unsatd. carboxylic acid monomer such as acrylic acid and methacrylic acid and 0.1-50wt% monomer such as styrene or vinyl chloride which can be copolymerized with the above-mentioned monomers are emulsion- polymerized so as to attain 100wt% in total. The resin film treating liquid prepd. by adding and mixing a silane coupling agent or titanate coupling agent as well as chromic acid and silica sol to and with the resultant copolymer resin having 10-200 acid value per solid content is coated on the steel sheet. The discoloration property and finger printability which are the disadvantages of the Cu-plated steel sheet are remarkably improved.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention forms a resin film with excellent corrosion resistance directly on the surface of a copper-plated steel sheet or via a paste film, thereby eliminating the drawbacks of copper-plated steel sheets. Learn about copper-plated steel sheets with improved color fastness and fingerprint resistance.

(Prior Art) Although copper-plated steel sheets have an excellent appearance, they have the disadvantage that the surface is easily oxidized in the atmosphere and turns brown, and scratches and fingerprints are easily noticeable when handled. For this reason, when manufacturing conventional copper plated 1llll sheets, chromate treatment, benzotriazole treatment, benzotrif(-) derivative treatment, etc. are applied to prevent discoloration, and treatments such as applying a protective film and strippable paint are applied to prevent scratches and fingerprints. I was going.

(Problems to be Solved by the Invention) However, even if chromate treatment or benzotriazole treatment is performed, discoloration can only be prevented for a short period of time. On the other hand, it was possible to prevent scratches and fingerprints during handling by attaching a film or applying strif bubble paint, but the processing cost was high and it took a lot of effort and time to remove them after processing. In addition, since Hou 1 film and trippaul paint do not have discoloration prevention properties, it was necessary to apply discoloration prevention treatment such as chromate treatment or benzotriazole treatment underneath.This prevents scratches and fingerprints. This required double processing.

On the other hand, although it requires double treatment, a cheaper method such as attaching a protective film or applying strif bubble paint may be to form a resin film with an aqueous solution of a water-soluble resin after discoloration prevention treatment. However, the only way to further improve color fastness with this method is to strengthen the color change treatment, so there is a limit to improving color fastness, so if 1i: To further improve color fastness. However, it was necessary to improve the corrosion resistance of the oil film and improve the discoloration property.

An industrially inexpensive method to improve the corrosion resistance of a resin film is to include hexavalent chromium in the resin film, but in order to incorporate hexavalent chromium using this method, it is necessary to treat the resin film containing hexavalent chromium. Must be treated with liquid. However, the resins conventionally used in such resin film treatment solutions were made hydrophilic by hydroxyl groups, and therefore, in order to contain hexavalent chromium in the treatment solution, chromic anhydride or chromate salts were used. When added, the hydroxyl groups of the resin molecules are oxidized, and the treatment liquid turns into a liquid, making it impossible to apply it to the steel plate.
In addition, hexavalent chromium is also reduced to trivalent chromium and does not exhibit discoloration. For this reason, it has been difficult to incorporate hexavalent chromium into conventional resin films.

(Means for Solving Problem 1) The present invention provides an organic coated copper-plated steel sheet that makes it possible to incorporate hexavalent chromium into the resin film, which was previously difficult to do. .

The copper-plated P steel sheet of the present invention is made of a water-dispersible copolymer that does not have hydroxyl groups as the resin of the resin coating to prevent the resin from being oxidized by chromic acid in the treatment solution stage, and the copolymer Acid value of coalescence? By incorporating a silane coupling agent or a titanate coupling agent, the water resistance, adhesion, and physical properties of the oil film are improved. That is, the present invention uses (A) one type of monomer represented by the general formula Cl2=CR, -COORI (in the formula, R1 is H, Cl1s, and Rz is an alkyl group having 1 to 8 carbon atoms) as the resin for the resin film; 1 to 95% by weight of two or more types, and (B) 3 to 20i of α,β unsaturated carboxylic acid monomer
1j1% and (C) 0.1 to 50% by weight of a monomer copolymerizable with these monomers [however, the total of (Al, (B) and (C) is 100% A copolymer with an acid value of 10 to 200 per solid piece obtained by mixing the oil with a silane coupling agent and/or a titanate coupling agent is used.

Here, the general formula CI+,=CR constituting the copolymer resin.

-COOR, examples of monomers include (ivy) ethyl acrylate, (meth) ethyl acrylate, (ivy) propyl acrylate, (/ri) butyl acrylate, (meth) acrylic a2-ethylhexyl, etc. Examples of α, β unsaturated carboxylic acid monomers include acrylic acid, methacrylic acid, itaconic acid, and maleic acid, and examples of monomers copolymerizable with these monomers include styrene, α -7
Tylstyrene, vinyl acetate, vinyl chloride, vinylidene chloride, etc. can be mentioned.

The reason for using the copolymer tJ4IIlt in the present invention is that a film having the desired physical properties can be obtained and it is easy to industrially produce copolymer O (fat). The reason for setting the value to 10 to 200 per solid content is
If it is less than 200, the water resistance is good but the adhesion to the steel plate is poor, and if it exceeds 200, the water resistance is poor and the corrosion resistance is reduced. The acid value is preferably set within the range of 15 to 100 because the film will have good water resistance and adhesion.

Even if one or both of the silane coupling agent and the titanate coupling agent are blended, it is preferable to blend 0.05 to 10 parts by weight per 100 parts by weight of the copolymer resin.There are various silane coupling agents. There are types of water dispersible or water soluble,
Monomer type [e.g. vinyltri(β-methoxyethoxy)silane, γ-glyndoxyprobyltrimethoxysilane 11, oligomer type (e.g. glycide type), resin modified type (e.g. acrylic modified, epoxy modified), cationic type Any type can be used. Furthermore, any water-dispersible or water-soluble titanate coupling agent can be used, and preferred examples include tetra(2,2-diallyloxymethyl-1-butyl)bis(twotridecyl)phosphite titanate, bis (Dioctylpyrophosphate)
Oxyacetate titanate, bis(dioctylpyrophosphate) ethylene rape), etc.

In the present invention, the resin film is formed as described above, and 6
Chromate is contained as a valent chromium source, and silica sol is further contained in order to improve the physical properties and corrosion resistance of the film. The chromate to be contained here is preferably a water-soluble and inexpensive one, such as chromium-117 ammonium,
Magnesium chromate, potassium dichromate, aA11! Calcium, zinc phosphate, mangamma chromate, nickel chromate, cobalt chromate, strontium phosphate, and the like can also be used.

The amounts of these chromates and silica sol to be contained in the resin film are 0.1 to 50 parts by weight for chromates and 0.5 to 100 parts by weight for silica sol per 100 parts by weight of copolymer resin. It is preferable that the thickness of the resin film is 0.2 to 10 μ-. If the thickness is less than 0.2 μ, it is difficult to form a uniform film, resulting in a spot-like film and poor discoloration. This is because it is poor in quality and has a small scratch-preventing effect. On the other hand, even if it is thicker than 10μ, the effect remains the same and the cost increases. A resin film with such content and film thickness is, for example, copolymer resin 20
0 to 400 Vt, a silane coupling agent or/and a titanate coupling agent of 0.1 to 40 Dino, a chromate of 0.2 to 200 Vt, and a silica sol of 1 to 400 Vt. can. Since the resin film contains chromate, it exhibits discoloration resistance even when formed directly on copper-plated steel sheets, but in order to exhibit even more discoloration resistance, a chromate film is formed on copper-plated steel sheets. and form on top of it. In this case, the type of chromium coating generally does not matter, such as reaction type or coating type, but it is preferable to rub the base of the coating with a total amount of 1 to 50++ g/11 chromium.
1.

The copper-plated steel sheets of the present invention include not only steel sheets plated with pure copper but also those plated with alloys containing additive metals, and the material steel sheets include not only cold-rolled steel sheets but also other steel sheets such as stainless steel sheets. Also included.

Next, the present invention will be explained by examples.

(Example) 50% by weight of methyl ivy acrylate and butyl acrylate) 401! Red acrylic emulsion silane obtained by emulsion polymerization of 10%, acrylic@9.8@wrinkle%, and 0.2% styrene [resin content 401! Amount%, PH2,3, viscosity2
5 cps (25°C, Type B viscometer), acid value per solid content of 78, hereinafter the FMI of the copolymer in this emulsion.
55% by weight of 1 and 1 methyl 7-acrylate with llt as X, 40% by weight of bunal acrylate, and acrylic 94
．． Acrylic emulsion prepared by emulsion polymerization of 7% by weight and 0.3% by weight of vinyl acetate [Resin content: 40% by weight]
, Pit 2.6, viscosity 150 cps (same as above), acid value per solid content 40, hereinafter the copolymer resin in this emulnone is referred to as Y], and a silane coupling agent or / as-made titanium F cup. Various ring agents, chromates, and silica sol (Nissan Chemical Co., Ltd.) are added to form a resin film treatment J! l! After adjusting the solution, this treatment solution was applied directly to the surface of a 0.61 copper-plated steel plate (@plating thickness 15 μm) manufactured by the following process or after forming a chromate film.

Copper-plated steel sheet manufacturing process N# Rolled steel sheet → Alkaline electrolytic defli! (Note 1) →Washing →
Acid cleaning (Note 2) Water washing → → Ni7 lattice plating (Note 3) →
Water washing → Copper plating (Note 4) → [Chromate treatment (Note 5)
→ Bark envy jJ! Liquid application → drying (150℃, 10 seconds)
.

(Note 1) Electrolyzed in a solution of N-section Si0.509711 at 70°C for 5 minutes at a current density of 5A/Da''.

(Note 2) Pickle in a 12% solution of lIc for 1 minute at room temperature.

(Note 3) NiSO<・611.0300 IIl,
NiC1, 6H, 045j//, Il, PO, 34f
/! , plating in a bath at 55° C. for 30 seconds at an electric density of 4^/D-y.

(Note 4) CuSO-201/muH,SO,401/l
Plating at a current density of 15^/Da'' in a bath at room temperature.

(Notes) Cry35 lap, 20 minutes in solution at 30℃
Second processing.

On the other hand, as a comparative example, a copper-plated steel sheet manufactured as described above was coated with a treatment coating containing neither a silane coupling agent, a titanate coupling agent, a chromate, nor a silica sol in Emaruno 1. We have adjusted the conventional discoloration prevention treatment. The chromate treatment in this comparative example was carried out using the treatment solution mentioned above (note 5), and the benzotriazole treatment was carried out using benzotriazole 51/J, 4
After being immersed in a solution at 0°C for 20 seconds, it was roll squeezed.

Thereafter, these samples were subjected to a wet O test and a fingerprint resistance test in the following manner.

(1) Humidity test According to JIS Z 0228, temperature: 50°C, humidity: 98°C
After being left in an atmosphere of %RH for 300 hours, the degree of discoloration of the plating surface was visually evaluated according to the following criteria.

0 All (No discoloration ○ Slightly browned Δ Browned Δ - Brown to blackened × Blackened (2) Fingerprint resistance test An artificial finger coated with artificial sweat was placed under a certain load!i (I Kg/a
m") on the material, and the attached fingerprints were visually evaluated according to the following criteria.

O Items where no fingerprints can be detected 0 Items where you can hardly tell whether there are fingerprints or no fingerprints Δ Items where you can see that there are fingerprints Δ - Items where you can see that there are a lot of fingerprints X Fingerprints Table 1 shows the conditions for forming a resin film and the results of these tests. Superior to those that have been subjected to conventional color change treatment or those that have a coating made of resin alone.
do.

(Effects) As explained above, the copper-plated holly steel sheet of the present invention does not contain water t11 groups in the resin of the coating ff (fat film), so even if the treatment solution contains chromate during manufacturing. , the resin does not oxidize or gel, and the resin film contains chromate, so it is more effective in preventing discoloration than conventional discoloration prevention treatments even with two-time treatment, and it also prevents scratches and fingerprints. Furthermore, since it also contains silica sol and a silane coupling agent or/and a titanate coupling agent, the resin film has excellent water resistance, adhesion, and physical properties.

Claims (2)

[Claims] (1) On the surface of copper-plated steel plate (A) General formula CH_2=C
R_1-COOR_2 (in the formula, R_1 is H, CH_3, R
_2 is 1 of the monomer represented by (C is an alkyl group of 1 to 8)
(B) 3 to 20% by weight of an α,β unsaturated carboxylic acid monomer; and (C) 0.0% by weight of a monomer copolymerizable with these monomers. 1 to 50% by weight [
However, the total of (A), (B) and (C) is 100% by weight
] Acid value 10 to 20 per solid content obtained by emulsion polymerization
0 copolymer resin mixed with a silane coupling agent and/or a titanate coupling agent, and is characterized by being coated with a coating containing chromate and silica sol. Organic coated copper plated steel sheet. (2) A chromate film is formed on the surface of the copper-plated steel sheet, and (A) General formula CH_
2=CR_1-COOR_2 (in the formula, R_1 is H, CH_
3, R_2 is 1 to 95% by weight of one or more monomers represented by C 1 to 8 alkyl group), (B) α,
3 to 20% by weight of a β-unsaturated carboxylic acid monomer, and (C) 0.1 to 50% by weight of a monomer copolymerizable with these monomers.
[However, the total of (A), (B) and (C) is 100
Weight %] Acid value per solid content obtained by emulsion polymerization: 10
~200 copolymer resin mixed with a silane coupling agent or/and a titanate coupling agent, and a resin film containing chromate and silica sol is formed and coated. Characteristic organic coated copper plated steel sheet.