JPS5819492A - Surface treated steel plate for easy to open end - Google Patents

Abstract

PURPOSE:To obtain a surface treated steel plate for easy to open end which is highly resistant to corrosion, does not require repair painting and is inexpensive by coating both surfaces of a steel plate with a Zn-Ni alloy or a Zn-Sn alloy and Sn and further providing a chromating layer thereon. CONSTITUTION:Two-element alloy coating layers 2,2 of Zn-Ni or Zn-Sn are provided on both surfaces of a cold roll steel plate 1 which is cleaned of the surfaces. Sn coating layers 3,3 are provided on the top surfaces thereof, and further chromating layers 4,4 are formed on the top layers. Oil film layers 5,5 are provided on the uppermost layers, whereby the surface treated steel plate is obtained. Oon the top surface side that comes on the outside surface side of cans, whether the Sn coating layer 3 shows by broken lines is provided or not can be selected according to need. The surface treated steel plate is produced by Sn plating, chromating and oil coating after application of two-element alloy plating. The two-element alloy coating layers are preferably in the range of about 0.5-5g/m<2> per one side, the Sn coating layers about 0.5-11g/m<2> per one side and the chromating layers about 2-50mg/m<2> per one side in term of metallic chromium.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface-treated steel sheet that is highly suitable for easy open ends (hereinafter referred to as HOE), which have been generally used for beverage cans in recent years.

Generally, electro-tin plated steel sheets (
(hereinafter referred to as tinplate), electrolytic chromic acid treated steel sheet (hereinafter referred to as TF
S-CT) is well-known and widely used for can bodies, single-can pigs, etc., but aluminum is mainly used as the material for EOGs. The reason for this is that in addition to the fact that aluminum has better opening properties than steel plates, aluminum gogs are better than tinplate and T F 8-
c Tl1iEoE is also said to have excellent corrosion resistance on the outside surface of the can and, except for some contents, such as salt-containing substances, on the inside surface of the can.

However, aluminum requires a large amount of electricity to refine, and steel plates are also expensive. Now, the characteristic required for EOK material is the inner surface properties of a single can.

The functions are corrosion resistance and the effect of preventing the elution of Fθ ions into the contents, and the external performance of the can is rust resistance and aesthetic retention in the EOE score processing area, rivet processing area, etc. Generally, as mentioned above, the EOE material is mostly aluminum, with a small portion made of tinplate, and the can body material is either tinplate, TFS, or OT, all of which are coated and used in combination before can manufacturing. When a can manufacturer or packer uses this material to wrap the EoE and the can body, if the ROE on the inside of the can or the coating on the can body is accidentally scratched, the packer may cause deterioration of the contents. This is not a good thing to happen. When the contents are, for example, fruit juice, the well-known Sn and Fe potential reversal phenomenon, that is, the phenomenon in which Sn elutes before Fe, occurs. EOE is sufficient. However, if the content is carbonated water such as cola or beer, the potential reversal phenomenon described above does not occur.
The effect of Sn to prevent Fe elution does not occur, and the elution of Fe ions into the contents proceeds. Therefore, for can manufacturers, EO
When using tinplate for E material, it is uneconomical to perform repair painting after tightening. In addition, as mentioned above, EOE is usually used after being painted, but during scoring, the coating on the inner surface of the can is not directly scratched, but the impact during processing causes small cracks and deteriorates. ° For the same reason as mentioned above, in the case of carbonated drinks, it was necessary to apply retouching coatings.

On the other hand, as mentioned above, the external performance of EOE is
The rust resistance and aesthetic appearance of the OE score processed parts, rivet processed parts, etc. are important from the viewpoint of product value and hygiene. EOE
Score processing processing section Verivet processing section During EOE manufacturing, it is subjected to severe impact processing, which damages the paint and plating layers, and especially in the case of tinplate EOE, the rust resistance becomes poor, so of course EOE
Repair painting was required after OE manufacturing.

As mentioned above, there are many problems with conventional aluminum and tinplate as EOE materials, and from the perspective of can recovery, there is a strong demand for all-steel cans, which provide excellent EOE suitability and inexpensive surface treatment. There were requests from various quarters for the development of steel plates.

As a result of conducting research in response to this, the present inventors succeeded in developing a completely new surface-treated steel sheet for EOE that fully satisfies the corrosion resistance of the inside and outside surfaces of cans, does not require repair painting, and is inexpensive. It is something.

The present invention is characterized by a novel surface treatment and construction method, specifically, a Ni-Zn or 5n-Zn binary alloy coating layer provided on both surfaces of a surface-cleaned steel plate; a Sn coating layer provided on at least one surface of the alloy coating layer;
Furthermore, it is a new material that is ideal for EOE and has a completely different coating form from conventionally known surface-treated steel sheets, which has a ridged layer structure with chromium-treated layers on both sides of the upper layer.

The coating structure of the new surface-treated steel sheet of the present invention is schematically shown in FIG.

l is the cold-rolled steel plate used as the material, Ni-Zn or an-Zn
Binary alloy coating +! 12 are provided. Although the Sn coating layer 3 is provided on the upper surface of the binary alloy coating layer 2, it is sufficient that the Sn coating layer is laminated on at least one surface, and of course, a double-sided multilayer structure may be used. For convenience of explanation, the first
In the figure, the top side of the drawing is used for the outside of the can, and the bottom side is used for the inside of the can, so the bottom side of the Sn coating layer 3 is always present, so it is shown as a solid line, and the Sn coating layer on the top side is free. It is indicated by a broken line so that it can be selected. 4 is a chromium-treated layer, and 5 is an oil film layer.

The new surface-treated steel sheet according to the present invention can be manufactured by various methods, and some of the manufacturing methods will be illustrated below, but of course, the method is not limited to these exemplified methods.

(A) Zn-Sn alloy layer and Zn-Sn alloy layer and S
N-layer multilayer coating method (a) A method in which Zn-Sn alloy plating is performed on a surface-cleaned cold-rolled steel sheet, followed by Sn plating, followed by chromic acid treatment and oil coating treatment. Usually, Zn--Sn alloy plating and Sn plating are performed by electroplating, and chromic acid treatment is performed by electrolytic treatment, but it is also possible to perform non-electrolytic treatment. The oil application process is usually electrostatic oil application process.

(b) First, Zn single plating is applied on a surface-cleaned cold-rolled steel sheet, and then Sn plating is overlaid, followed by heat treatment (for example, reflow treatment) to form a Zn-Sn alloy layer, and on this alloy layer, Same as (a) directly without Sn plating,
A method of chromic acid treatment and oiling treatment.

However, since it is necessary to overlay the Sn layer on the Zn--Sn alloy layer on at least one side, the pSn layer can be left by making the Sn plating layer thicker in advance or by appropriately selecting the heat treatment conditions. Note that the Zn and Sn plating is usually performed by electrolytic treatment, but non-electrolytic treatment is also possible.

(B) Zn-Ni alloy layer and Zn-Ni alloy layer and S
N-layer multilayer coating layer (c) After applying Zn-Ni alloy plating on the surface-cleaned cold-rolled steel sheet, the same method as in (a) (Sn plating, chromic acid treatment and oil coating treatment. Zn-Ni Alloy plating, S
N plating is usually done by electrolytic treatment, but non-electrolytic treatment is also possible.
i After forming the alloyed layer, use the same method as in (a) (Sn plating, followed by chromic acid treatment and oil coating treatment. Zn, Ni, and Sn plating are usually performed by electrolytic treatment, but non-electrolytic treatment is also possible. Possible.

In the present invention, the structure of the coating layer is particularly important, and although there is no need to specifically limit the numerical values of each layer, preferred numerical ranges are described below.

The upper layer of the N1-Zn or en-Zn binary alloy layer is 0, 5-5 y/ll on one side, the snn skin layer is on one side fi,
The most preferable results are obtained when the chromium-treated layer has a value in the range of 2 to 501 in terms of polymetallic chromium per side. Note that it is not necessary to limit each coating layer to the same amount of coating on the front and back surfaces, and plating with different thicknesses is also possible depending on the required application. For example, the plating thickness can be made thicker on the inner surface of the can than on the outer surface of the can.

When the new surface treatment with the novel coating layer of the present invention is applied to the inner surface of the can using EOE, especially the Ni-Zn or 0n-Zn binary alloy coating system, if the alloy ratio is adjusted optimally, electrochemical In addition, since it is slightly more anodic than Flil in various contents, it is possible to effectively suppress the elution of Fe ions from the eaves even if the coating layer is damaged during the can manufacturing process.

Here, we briefly explain why Ni-Zn or 1d 19n-Zn binary alloy.

The reason why the coating system prevents the elution of Fe ions will be explained. In the case of a multilayer consisting of a single layer of N1 coating and a single layer of Sn coating, the Ni coating layer is very noble in potential, so there is no effect of preventing the elution of Fe ions, and the single layer of Zn coating and the S
On the contrary, in the case of a single layer of N coating, the Zn coating layer is very anodic, so even if the effect of preventing Fe ions is large, the elution rate of Zn is too fast and the effect does not last for a long period of time. Corrosion resistance deteriorates and is inappropriate. Tsuma F) N
Zn such as i-Zn, 5n-Zn binary alloy
If the ratio of and N1 or 19n is appropriately selected and alloyed,
This method takes advantage of the fact that the potential is slightly more anodic than that of Fe, and the effect of preventing elution of Fe ions can be maintained stably for a long period of time.

On the other hand, when the new surface treatment of the present invention is applied to the outer surface of the can of g The sacrificial anti-corrosion effect can suppress the rusting from the Fe exposed parts of the coating film and plating defects that occur after can manufacturing, and by selecting the alloy ratio ε, the anti-corrosion effect can be maintained for a long period of time. Repair painting after EOE can manufacturing, which was essential, becomes unnecessary or can be simplified. g
og outer surface side (20n) Whether or not to overlay the imitation layer on the binary alloy layer depends on its intended use, for example, when a higher degree of external corrosion resistance is required, or when the color tone of the Sn coating layer is important. etc., should be selected at the appropriate time.

As mentioned above, if the surface-treated steel sheet for EOE of the present invention is used, it can compensate for the drawbacks of conventional tin ROE and have performance close to that of aluminum EOE. Converting to this method will help significantly reduce can manufacturing costs and make it possible to manufacture all-steel cans, which are required to achieve the same yield as cans.

Specific examples of the present invention will be described below.

[Example 1] Ni-Zn binary alloy plating was applied to both sides of a steel plate whose surface had been cleaned in the usual manner under the plating conditions shown in (1), and Sn plating was applied to only one side under the conditions shown in (2). Ta.

Further, a chromium-treated layer was formed under the conditions shown in (3) and (4). After this, both surfaces of the plated steel plate of the present invention are shown in (5).

A coating film for can manufacturing was formed under the following conditions and subjected to various tests.

(1) N15O, -6H20100~300 f/
l Bath temperature 50'CH3BO330f/1 (2) Tin sulfuric acid 259/l Bath temperature 4
0'C phenolsulfonate 3oy/l $
Flow density zoh/awt (65% solution) Ethoxylated α-naphtholsulfonic acid 22/1 (3) NcL2Cr207 25 f/1 Bath temperature 4
0~70℃ Current density 10A/dm” (4) 0
r03 50? /L H2SO40,4f/l (804 conversion) Bath temperature 50
°C Current density 10-40 Aldy/(5)
Coating 45η/d of epoxy-phenol paint (dry weight per side) Baking at 205°C x 10 minutes [Example 2] 5n-Zn coating was applied to both sides of a steel plate whose surface had been cleaned in a conventional manner under the conditions shown in (1). Gold plated on only one side (
Sn plating was performed under the conditions shown in 2). Furthermore, (3) (
After forming a chromium treatment layer under the conditions shown in 4), a coating film for can making was formed on both sides of the present invention under the conditions shown in (5), and subjected to various tests.

(1) S n S O4100-300f/7Zn
S04 ・6H2040~1509/l Bath temperature 50
℃N a 2 s 0. 1 o o t/l
Current density 5-10A/ds' citric acid
20 f/1 (2)? (5) Same as (2) to (5) of Example 1 [Example 3] Zn plating was applied to both sides of the steel plate whose surface had been cleaned by the usual method under the conditions shown in (1), and further, (2) ) After applying Sn plating with different thicknesses on the front and back sides under the conditions shown in (3), reflow treatment is performed under the conditions shown in (3) to alloy sn and Zn. layer and Sn layer, and the other side (outer surface side of the can) is 5n
- Only the Zn alloy layer was formed.

Furthermore, after forming a chromium treatment layer under the conditions shown in (4), a coating film for can making was formed on both sides of the present invention under the conditions shown in (5), and subjected to various tests.

(1) Zn5O,-'6H20100-300r/
l Bath temperature 50'C (3) 4 y/l SnSO
d into 7 lux of 4-4yμphenolsulfonic acid
After ip, it is rapidly heated to 270° C. by direct electricity, and immediately cooled down in water.

(4) Same as (4) of Example 1 (5) # # (5) # As test items, items (A) to (F) shown below were performed and the performance was evaluated. Items (A) to (0) were performed only on the multi-layer coated surface because of the performance required for the EOE inner surface, but other tests were carried out on both the multi-layer coated surface, Ni-2n or 8n-zn single-layer coated surface.

(A) UCC (undercut colonization test) After scratching the coating film of the above sample reaching the base metal with a knife, apply a corrosive solution (1.5% citric acid - 1.5% N, O
j), saturated with CO□ gas,
After being maintained at 0°C for 3 days, the scratched area was peeled off with tape and the corrosion state around the scratch was determined.

(B) Corrosive liquid immersion test After EOE scoring was applied to the above sample and the score structure side (outer side of the can) and end face were sealed with wax, the inner side of the can (layered side) was removed without any repairs. The specimens were immersed in 100% orange juice, cola, beer, and tomato juice and kept at 50°C for 14 days, after which the state of surface corrosion was evaluated.

(c) A sample similar to Eo, b internal aptitude test (B) was prepared by using a knife to make scratches reaching the base metal on the painted surface of @25ET painted in the same manner as in (b) in Fuka Cola. After immersing it in water and connecting it with electric wire to form a galvanic couple,
After holding at 28° C. for 10 days while maintaining Co and gas saturation, evaluation was made based on the galvanic current value flowing between the two measured with a non-resistance ammeter and the amount of Fe eluted into Fuca-Cola.

Here, the current value ■ is Fe anodic (that is, Fe elution).

O//i indicates that it is cathodic.

(D) Paint film adhesion test The above sample as is (primary adhesion), 3% N, Cj
After immersion in the solution and retort treatment at 125°C for 90 minutes (secondary adhesion) and after the UOC test in (A) (UC
Adhesion (after adhesion) was evaluated by making goblets at two difficult intervals on the coating film with a knife and peeling off the tape.

(E) Rust resistance test on the external surface of the can After scratching the painted surface of the above sample reaching the base metal with a knife, it was tested in a warm moisture tester at 50°C and RH 9n%.
hr and kept in a constant temperature and humidity tester at 30° C. and RH 80% for one month, and then evaluated based on the rusting state from the scratched portion.

(F) EOE external aptitude test The EOE score was processed on the above sample, and the score structure was left unrepaired using a QC tester for 30 minutes - Dr.
A cycle of 60 minutes (water temperature 20° C., air 50° C.) was performed for 200 cyc2e (score structure rusting status after repeated cycles).

The evaluation results of (A) to (F) above are shown in Table 1.

Table 1 Invention Examples 1 to 3 are an/Ni-Zn multilayer, 4 to 6
fi Sn/5n-Zn multilayer, 7.8 is Ni-Zn single layer, 9°10 is 5n-Zn single layer, and has excellent EOE suitability. Comparative Example 1 is a single layer of Sn/Zn, and its suitability for the inside of the can is extremely poor, and its suitability for the outside is also unfavorable because white rust, which is characteristic of Zn, occurs.

Comparative Example 2 was evaluated using a single S n/N i layer (A), (B)
Although it is excellent in (C) EOE internal aptitude and (g) (
r) E OE external aptitude is slightly inferior. Comparative example 3 is Sn/
N1-zn but without chromium treatment layer, (A) (B
), and especially (D) coating film adhesion is extremely poor. Comparative example 4,
5 is for Zn and N1 single layers, each with EOII
C: Poor external aptitude.

As can be seen from the examples described above, the new surface-treated steel sheet of the present invention has excellent performance as a material for EOIIC, and a great effect can be obtained by configuring the plating structure according to the location where it is used. Obtainable.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing one example of the new surface-treated steel sheet of the present invention. l...Cold rolled steel plate 2...Ni-Zn or 5n-Zn binary alloy coating layer 4
... Rim treatment layer 5 ... Oil dam layer procedural amendment dated September 1980, Director General of the Japan Patent Office Shima 1) Haruki Tono l Indication of the case 1982 Patent Application No. 116475 2, Invention Name Surface Treated Steel Sheet 3, Relationship with the person making the amendment Patent applicant address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name
(665) Nippon Steel Corporation Representative Takeshi 1) Toyo 4 Agent 105 Den (503) 4877 Address 7th Floor, Daiichi Mori Building, 1-12-1 Nishi-Shinbashi, Minato-ku, Tokyo Contents of Amendment (1) , the title of the invention is amended as follows: "Surface treated steel sheet" (2. The scope of the claim is amended as follows. [Zn and N1 or Sn provided on both surfaces of the surface-cleaned steel sheet.
It has a binary alloy coating layer, an AN coating layer provided on at least one side of the alloy coating layer, and a Nipm treatment layer on both sides thereof, and the multilayer coating side is the inner surface side of the can. Surface treated steel plate used for. (3) Add the following sentence between the second and third lines of page 10 of the specification. "Although the surface-treated steel sheet of the present invention is especially suitable for EOE, it can also be used for general can bodies, as it has particularly excellent seam weldability. Cans using seam welding as the can body joining method It can also be used for body applications.

Claims (1)

[Claims] A binary alloy coating layer of Zn and N1 or Sn provided on both sides of a surface-cleaned steel plate, a Sn coating layer provided on at least one side of the alloy coating layer, and a chromium treatment layer on both sides of the upper layer. A surface-treated steel plate for easy open ends that is used so that the layered coating side is on the inside surface of the can.