JP2000233248A - Method for manufacturing easy-open lid and lid - Google Patents

Abstract

(57) [Problem] To provide an easy-open lid whose score processing technology can be manufactured economically without repair painting of the score part, with the same level of ease of production as the current score processing method. SOLUTION: In the manufacture of an easy-open lid, the main composition is as follows: C: ≤ 0.20 wt%, Mn: ≤ 1.0 wt%,
P: ≤0.15 wt%, S: ≤0.100 wt%, solA
l: ≦ 0.150 wt%, B: ≦ 0.0070 wt%,
Further, one or more of Nb and Ti are ≦ 0.10
A surface-treated steel sheet having a composition containing wt% as required, and having Sn or Sn alloy plating of 2.0 to 15.0 g / m ² or more applied to the innermost layers on both front and back surfaces, and having a circular cross section of the score blade tip. A scoring blade having an arc shape and a radius of 0.040 to 0.300 mm is subjected to scoring on the inner and outer surfaces of the lid, so that Sn or Sn alloy remains on the entire surface of the score groove.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel easy-open lid which does not require repair coating and has excellent corrosion resistance at a score portion, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Recently, a score of an appropriate shape and depth is stamped on a can lid such as a beverage can or a food can, a tab for opening the can is attached, and the score is pulled outward by pulling the tab. Pa that can be easily opened by being torn
By causing rtial-EOE or a tab, the score part is torn inward and can be opened easily, the tab remains inside, and the tab does not scatter on roads, parks, etc.
A tab-EOE lid is used.

[0003] The material of this easy-open lid includes steel and aluminum. Aluminum lids cannot be used for all contents from the viewpoint of corrosion resistance, and steel lids are often used especially for contents containing salt. Also,
Aluminum lids are inconvenient from a recycling perspective for steel can lids. On the other hand, steel easy-open lids require scoring to be repair-painted in order to compensate for the deterioration of the corrosion resistance of the scored part due to the plating and coating of the scored part being destroyed by the score processing. There is a problem that it is larger than aluminum.

[0004] As a method of eliminating the repair coating of the score portion, Japanese Patent Application Laid-Open No. 9-234534 discloses a method of “thickness 10
It has a resin coating having a breaking elongation of at least 100% and a breaking elongation of at least 100%.
Using a mold having a thickness of 0.3 mm, the plate is pressed and formed at the shoulder radius of the upper and lower molds, and the metal thickness of the thinnest part is thinned to 1/2 or less of the metal thickness before processing. An easily openable lid and a method for manufacturing the same ", and a method for manufacturing a resin-coated can lid with excellent openability disclosed in JP-A-8-224626. A method for press-forming a plate is disclosed. In this method, the resin film coated on the steel plate is a special shape that the plate is pressed and formed with the shoulder radius of the upper and lower molds because the resin is broken and the corrosion resistance cannot be secured with the current inverted trapezoidal score blade shape. This is a method to ensure the soundness of the film and eliminate the need for repair painting by performing processing. Accordingly, in the press forming, the plate is pressed at the shoulder radius of the upper and lower molds, that is, the shearing with a kind of R-shaped blade is stopped in the middle of the shearing, and the thinnest portion corresponding to the score remaining thickness is formed. It requires a high technical ability to control the metal thickness in μm units, which increases the cost of the mold and the cost of molding. On the other hand, no proposal has been found for a method that is as good or better than the score blade wear. As described above, the scoring technique is also at the same level of ease of production as the current scoring method and without repair painting of the score part, and furthermore, the score blade is less worn and economically superior manufacturing method and easy open lid. Provision is desired.

[0005]

The problem to be solved by the present invention is that the scoring technique has the same level of ease of production as the current scoring method and can be economically manufactured without repair painting of the score portion. An object of the present invention is to provide an open lid manufacturing method and an easy open lid.

[0006]

Means for Solving the Problems The present inventors have found that the scoring technique has the same level of ease of production as the current scoring method, and that the outer surface side of the lid does not need to ensure flavor properties, but only corrosion resistance. For this reason, the present invention was completed by intensive studies on a method for economically securing corrosion resistance without applying expensive resin coating, and the present invention is as follows.

(1) In manufacturing an easy-open lid,
C: ≤ 0.20 wt%, Si: ≤ 0.5 wt%, Mn: ≤
1.0wt%, P: ≦ 0.15wt%, S: ≦ 0.100wt
%, SolAl: ≦ 0.150 wt%, N: ≦ 0.015
0 wt%, B: ≤ 0.0070 wt%, Nb, Ti
One or more of them contain ≦ 0.10 wt% as necessary, and the balance is composed of Fe and unavoidable elements, and the innermost layer on both the front and back surfaces has a S content of 2.0 to 15.0 g / m ² .
Using a surface-treated steel plate to which n or Sn alloy plating has been applied, a score blade having a cross section of a score edge having an arc shape and a radius (R) of 0.040 to 0.300 mm, and performing a scoring process on the inner and outer surfaces of the lid. By doing so, S on the entire surface of the score groove
A method for manufacturing an easy-open lid that does not require repair painting, characterized by allowing n or Sn alloy to remain. (2) In the manufacture of the easy-open lid, the composition of the above (1), wherein the innermost layer of the surface corresponding to the outer surface side of the lid has 2.0 to 1
5.0 g / m ² of Sn or Sn alloy plating is applied,
Using a surface-treated steel sheet having a resin film of 5 to 100 μm applied to the outermost layer on the surface corresponding to the inner surface side of the lid, the cross-sectional shape of the score cutting edge is arc-shaped and the radius (R) is 0.040 to 0.30.
With a score blade of 0 mm, by performing scoring on the inner and outer surfaces of the lid, Sn or Sn alloy is left on the entire surface of the score grooves on the outer surface of the lid, and the resin film is not damaged on the entire surface of the score grooves on the inner surface of the lid. A method for manufacturing an easy-open lid which does not require repair painting and has excellent flavor characteristics.

(3) C: ≦ 0.20 wt%, Si: ≦ 0.
5 wt%, Mn: ≦ 1.0 wt%, P: ≦ 0.15 wt%,
S: ≤0.100 wt%, solAl: ≤0.150 wt
%, N: ≦ 0.0150 wt%, and B: ≦ 0.0070
wt%, and one or more of Nb and Ti are ≦
0.10 wt% if necessary, the balance being Fe and unavoidable elements.
An easy-open lid made of a surface-treated steel sheet plated with 15.0 g / m ² of Sn or Sn alloy, having a score on the inside and outside of the lid, and a score groove bottom having an arc shape. And the radius (R) is 0.040 to 0.30
An easy-open lid that does not require repair painting, characterized in that Sn or Sn alloy remains on the entire surface of the score groove on the inner and outer surfaces of the lid. (4) In the composition of the above (3), the innermost layer of the surface corresponding to the outer surface of the lid is plated with Sn or Sn alloy at 2.0 to 15.0 g / m ² , and the inner surface of the surface corresponding to the inner surface of the lid is coated. 5 for the outermost layer
An easy-open lid made of a surface-treated steel sheet provided with a resin coating of 100 μm, having a score on the inner and outer surfaces of the lid, a score groove bottom shape of an arc shape, and a radius (R) of 0. 0.040 to 0.300 mm, Sn or Sn alloy remains on the entire surface of the score groove on the outer surface of the lid, and the resin film remains on the entire surface of the score groove on the inner surface of the lid without being damaged. Easy-open lid with no need for repair painting and excellent flavor.

Hereinafter, the present invention will be described in detail. The present inventors have found that the reason why the current S-EOE requires repair painting is as follows: 1) The can coating on the Sn plating layer on the upper side of the Sn plating layer for ensuring the corrosion resistance of the outer surface of the lid is a sharp corner of an inverted trapezoidal score blade. Has been cut and deleted in the department 2)
Paying attention to the fact that the Sn plating layer has been deleted at the sharp corner portion of the inverted trapezoidal score blade, various investigations were conducted on a method of leaving one of the layers from the viewpoint of ensuring corrosion resistance, and further, Various studies were also conducted from the viewpoint of improvement in can openability, and the easy open lid of the present invention was found.

First, in order to secure corrosion resistance by optimizing the coating of a steel sheet, in the case of scoring with an inverted trapezoidal score cutting edge having a sharp corner portion, various resin coatings or various plating conditions were examined. In the range of practical conditions, it was not possible to find one having a level of corrosion resistance at which corrosion resistance could be secured and repair painting could be omitted.

[0011] Next, the present inventors have conducted various studies such as forming a sharp corner portion of a trapezoidal score cutting edge with R, and found that Sn or Sn of 2.0 to 15.0 g / m ² was formed on the surface of the steel sheet. -A surface-treated steel sheet on which a Sn alloy plating such as Zn, Sn-Ni, etc., has a score cutting edge shape of an arc shape and a radius (R) of 0.040 to 0.300 mm when subjected to scoring with a score blade. It has been found that Sn or Sn alloy can be left on the entire surface of the score groove. As shown in FIG. 1, the score part in the range of the present invention has excellent corrosion resistance, and it can be seen that a lid can be obtained in which the repair coating of the score processed part can be omitted.

FIG. 2 and FIG. 3 show an S-section of a score groove cross section having a radius of 0.100 mm and an R-shaped bottom of the score groove.
FIG. 4 schematically shows the state of remaining Sn of the n-plated layer or the resin film, and FIG. 4 schematically shows the state of remaining Sn of the comparative example in which the conventional groove bottom is flat.

FIG. 1 shows a test in which an epoxyphenol-based can was coated on T-50 # 50 / # 50 tin (weight per tin (front / back): 5.6 / 5.6 g / m ² ). Using a material, the tip of the score part has an arc shape and the radius of the arc is changed to perform scoring on the inner and outer surfaces of the lid. The arc radius (R) of the score groove and a 5% -35 ° C salt spray 24Hr test FIG. 6 is a graph showing the relationship between the score portion and the percentage of occurrence of red rust after the score portion.
If it is 300 mm, it will be excellent, and it can be seen that the repair painting of the score part can be omitted.

As a result of conducting detailed experiments on the Sn basis weight of the material and the like, it was found that if the Sn plating is at least 2.0 g / m ² or more, the Sn plating layer is substantially left on the entire surface of the score groove. However, it has also been found that the type of plating may be any Sn alloy plating such as Sn-Zn or Sn-Ni used for food cans or beverage cans.

The present inventors have proposed that Fe or S be added to the contents of a can.
An investigation was also made on the improvement of the flavor property made possible by suppressing the elution of n. As a result, even under the scoring conditions of the present invention in which the inner surface of the lid is scored, a surface-treated steel sheet having a resin coating of 5 to 100 μm applied to the outermost layer of the surface corresponding to the inner surface of the lid is used, The cross-sectional shape is an arc and its radius (R) is 0.040-
If score processing is performed with a score blade of 0.300 mm, it is possible to leave the resin film on the entire surface of the score groove on the inner surface of the lid without damage, and not only repair painting is unnecessary, but also flavor Even an excellent easy-open lid could be manufactured.

Further, the inventors of the present invention have also examined the openability. As a result, in the conventional inverted trapezoidal score groove, the shear strain is concentrated on the sharp corner formed between the groove side wall and the groove bottom plane, and the score is increased. If the remaining thickness is reduced, cracks or necking occur, and the score remaining thickness portion is easily broken.
In contrast to 0 μm, which is a practical limit, the easy-open lid of the present invention has a score bottom of 0.040 to
Since it has an arc of R of 0.300 mm, the plastic working strain in the remaining thickness portion of the score is not mainly shearing strain but mainly compressive strain and is relatively uniform, so that cracks are unlikely to occur and the score remaining thickness is extremely thin. The easy-open lid with a score remaining thickness of 30 to 40 μm has excellent openability, and furthermore, by providing arc-shaped scores on both the inner and outer surfaces, the stress at the time of opening can be reduced. It was also found that the openability was improved by concentrating on the bottom of the groove.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The constitutional conditions of the present invention will be described in detail below. The steel plate composition of the easy-open lid of the present invention,
C, Si, Mn, P, S, solAl, and N are all elements that strengthen the material of the steel sheet, and C: ≦ 0.20 wt%,
Si: ≦ 0.5 wt%, Mn: ≦ 1.0 wt%, P: ≦ 0.
15 wt%, S: ≦ 0.100 wt%, solAl: ≦ 0.
If the content exceeds 150 wt% and N: ≦ 0.0150 wt%, the quality becomes high and the can openability is impaired. Therefore, it is necessary to regulate the content in these ranges. B is
N is fixed as BN and has the effect of preventing aging deterioration due to solid solution N, so it may be added as necessary.
If the amount exceeds the range of ≦ 0.0070 wt, adverse effects such as excessive hardening of the material will occur. Therefore, it is necessary to restrict the amount to this range. Further, one or two of Nb and Ti
When the seed is added in a range of ≦ 0.10 wt%, C and N are converted to TiC, NbC, Ti when producing a steel sheet by the continuous annealing method.
N can be fixed, and a soft, non-aging material can be obtained, so that it may be added as needed. However, even if it exceeds this range, no special effect is obtained and the alloy cost is increased. Therefore, it must be restricted to this range, and the balance must be a steel composition comprising Fe and unavoidable elements.

The steel plate of the easy-open lid of the present invention is not particularly limited as long as it can melt the steel having the above-described composition to form a slab.
It is necessary to particularly regulate a hot-rolled steel sheet that has been manufactured according to a conventional method and that has been subjected to cold rolling, recrystallization annealing, and high temper rolling of 5% or less or 5 to 40% as required. Absent.

The surface treatment of the surface corresponding to the outer surface of the lid is performed using Sn
Plating or Sn alloy plating such as Sn—Zn or Sn—Ni may be used, but the basis weight of the plating is 2.0 g / m 2 to leave the plating layer on the entire surface of the score groove.
^Two or more are required. It should be noted that the upper limit does not need to be particularly restricted from the viewpoint of corrosion resistance. However, even if it exceeds 15 g / m ² , the effect of improving corrosion resistance is saturated and the cost increases, so the upper limit was set to 15 g / m ² .

The bottom of the score groove has an arc shape, and as shown in FIG. 1, the radius R of the arc is 0.040 to 0.300 mm.
By restricting to Sn or Sn on the entire surface of the score groove
The alloy can substantially remain, and the corrosion resistance of the score portion shows excellent characteristics, and a lid can be obtained in which the repair coating of the score processed portion can be omitted.

The surface treatment of the surface corresponding to the inner surface of the can may be the same treatment as that of the surface corresponding to the outer surface of the can, for example, a surface treatment in which the tin is coated on Sn plating. In order to suppress the dissolution of Fe or Sn and obtain excellent characteristics in flavor, as shown in FIG. 3, a surface-treated steel sheet having a 5-100 μm resin coating on the outermost layer corresponding to the inner surface side of the lid is used. In this case, the resin film having a thickness of 3 to 100 μm can be left without being damaged, and the flavor property is also excellent. In this case, the undercoating treatment of the resin coating is the same in the case of TFS plating, and is the same in the case of tin plating or LTS (thin Sn coating) plating.
It is preferable to secure adhesion by plating the plating with, for example, 25 mg / m ^{2 using} electrolytic chromate.

Further, the score groove of the present invention is 0.040
Since scores are applied to the inner and outer surfaces of the lid with a score blade having an arc of R of about 0.300 mm, the stress concentration in the score groove at the time of opening the can can be increased and the openability can be improved. The shape of the cutting edge is circular and the radius of the circular arc is 0.040
Utilizing that it is ~ 0.300mm, the score remaining thickness is 3
The easy open lid having a thickness as small as 0 to 40 μm can provide more excellent can openability.

In the case of a lid using a steel sheet coated with a laminate, after scoring, heating to 180 to 280 ° C. and cooling can repair the flaws of the resin film generated by scoring and pressing. It can be employed as appropriate because corrosion resistance can be further improved.

[0024]

EXAMPLES The effects of the present invention will be described below with reference to examples. A slab having the components shown in Table 1 was prepared, hot-rolled under the conditions shown in Table 2, cold-rolled to 0.22 mm, and TP after recrystallization annealing.
A surface-treated steel sheet was manufactured on a cold-rolled steel sheet that had been M-rolled by the usual method under the conditions shown in Table 2.

The base treatment for resin coating or can coating is T
In the case of FS (total Cr content in electrolytic chromate: 100 mg / m ² ) plating, it is the same, and in the case of tin plating, 5.6 to
25 mg / m ² was electrolytically chromated on the 11.2 g / m ² Sn plating, and the LTS (Sn: 1.3 g
/ M ² ) In the case of plating, 25 mg / m ² was applied on the LTS plating by electrolytic chromate to secure adhesion. In addition, the coating for cans was made by applying an epoxyphenol-based lid coating.
In the resin coating treatment, a molten PET-based thermoplastic resin was directly extruded from a die onto a heated steel sheet to coat a predetermined thickness, and immediately cooled to suppress crystallization, thereby obtaining a ductile resin-coated steel sheet.

The scoring was performed by the Stay-on-tab-EOE, and the scoring groove shape and the score remaining thickness shown in Table 3 were scored. Note that, in Table 3, No. After attaching the tabs, the lids of 5 and 11 were heated and melted at 220 ° C and immediately cooled with water.
The adhesion of the coating resin was further enhanced, and the test lid was used. Investigation of cracks in the remaining thickness of the score was observed with a light microscope.
Those with cracks or necking were evaluated as x, and those without cracking were evaluated as ○. Evaluation of the soundness of the Sn plating layer or resin film remaining on the score groove surface
The cross section of the score groove was observed with a SEM or an optical microscope for the remaining state of the Sn plating layer or the resin film. Those were evaluated as x.

The corrosion resistance of the score part was evaluated by performing a salt spray test (12 hours) and evaluating the occurrence of red rust in the score part. Is flowing from the score part, and was evaluated as x. The corrosion resistance of the wound part was evaluated by performing a salt spray test (12 hours) after the tightening. A sample without red rust was evaluated as ○, a sample with red rust was evaluated as x, and a red rust was observed even in the salt spray test (100 hours). Those that did not occur at all were evaluated as ◎. The openability was evaluated by pulling with a tensile tester to open the cans, and evaluated according to the Pop value (opening force at the time of first opening).

No. 1 is a conventional score-groove bottom shape having a flat surface, in which the width of the groove bottom plane portion is 50 μm.
In the comparative example, the score remaining thickness of the conventional shape was 50 μm and the thickness of the conventional shape was thin. The Sn plating layer of the score groove was removed at the sharp corner of the inverted trapezoidal score. bad. In addition, since the inverted trapezoidal score is as thin as 50 μm in remaining thickness of the score, necking is included in the remaining thickness of the score, so that the corrosion resistance on the inner surface side is deteriorated.

No. Samples 2, 3, and 4 used test steel sheets manufactured within the manufacturing conditions of the present invention, the score groove bottom shape was an arc, the radius of which was 100 or 150 μm, and the score remaining thickness was 4
In each of the examples of the present invention having a thickness of 0 μm, the soundness of the Sn plating layer or the coating resin in the score grooves is secured, and the corrosion resistance of the score grooves is good. Also, the openability is good. No. 5 is an example of the present invention, and the remaining score is 3
With a thickness of 5 μm, it is possible to achieve both a further improvement in the can openability and a securement of the corrosion resistance of the score portion.

No. Nos. 6, 7, and 8 used test steel sheets manufactured within the manufacturing conditions of the present invention. In No. 6, the radius of the arc at the bottom of the score groove is 20 μm, In No. 7, the radius of the circular arc at the bottom of the score groove is 400 μm, 8 is a comparative example in which the score groove bottom shape is an inverted trapezoid, and all deviate from the score conditions of the present invention, or the soundness of the Sn plating layer or the coating resin of the score remaining thickness portion is insufficient and the corrosion resistance is poor, Po
When the p-value was 0.3 kg, the score portion had already broken and the function as a can was not maintained.

No. Nos. 9, 10, and 11 are examples of the present invention in which the composition of the steel is an ultra-low carbon soft steel. 9 is R200μ
m, the score remaining thickness is 40 μm. 10 is R150μ
No. m, the score remaining thickness was 40 μm. 11 is an example in which a score is applied to both the inside and outside of the lid to reduce the remaining thickness of the score, and the openability is improved.

No. No. 12 had a Mn content of 1.8 in the steel composition.
In the comparative example hardened to 0%, the can openability was poor at 3.0 kg. No. No. 13 is a comparative example using a surface-treated steel sheet having a Sn weight per unit area of 1.1 g / m ^2, which is less than the Sn weight per unit area of the present invention, and the corrosion resistance was not ensured.
In addition, No. The cans of Examples of the present invention using steel sheets having resin coating on the inner surface side of 4, 5, 9, 10, and 11 had excellent inner surface corrosion resistance and good flavor.

As is clear from the results of the above embodiments,
It was confirmed that the easy-open lid of the present invention can secure good corrosion resistance on the outer surface side of the lid by using an expensive Sn-plated steel sheet that is not coated with an expensive resin, and that the one with a reduced score remaining thickness is also excellent in openability. done. The types of the easy-open lids to which the steel sheet of the present invention is applicable are Partial-EOE, Stay-o
Either the n-tab-EOE or the Full-EOE lid does not impair its effect.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

As described above, the present invention has been described in detail. However, the method for manufacturing the easy-open lid and the lid according to the present invention are the same as those of the present invention. To provide an easy-open lid that can be manufactured economically at a level of ease of manufacture and without the need for repair coating of the score portion ", and has an extremely large industrial value.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a radius R of a score groove bottom provided on the inner and outer surfaces of a lid and SST corrosion resistance of the score groove.

FIG. 2 is a view schematically showing the state of the Sn plating layer having a cross section of the score groove having a radius of 0.150 mm and a radius of 0.150 mm.

FIG. 3 is a diagram schematically showing a residual state of a resin film in a cross section of a score groove having a radius of 0.150 mm and an R-shaped bottom of the score groove of the present invention.

FIG. 4 is a diagram schematically showing a resin film remaining state of a comparative example in which a conventional groove bottom shape is a flat surface.

Claims (4)

[Claims] In the manufacture of an easy-open lid, C:
≦ 0.20 wt%, Si: ≦ 0.5 wt%, Mn: ≦ 1.0
wt%, P: ≦ 0.15 wt%, S: ≦ 0.100 wt%, s
olAl: ≦ 0.150 wt%, N: ≦ 0.0150 wt
%, B: ≦ 0.0070 wt%, and one or more of Nb and Ti contain ≦ 0.10 wt% as necessary, and the balance is composed of Fe and unavoidable elements. The innermost layer is made of a surface-treated steel sheet plated with 2.0-15.0 g / m ² of Sn or an Sn alloy, and the cross-sectional shape of the score blade is arc-shaped and the radius (R) is 0.04.
A method of manufacturing an easy-open lid that does not require repair painting, characterized in that Sn or Sn alloy is left on the entire surface of the score groove by applying a score process to the inner and outer surfaces of the lid with a score blade of 0 to 0.300 mm. . 2. In the manufacture of an easy-open lid, C:
≦ 0.20 wt%, Si: ≦ 0.5 wt%, Mn: ≦ 1.0
wt%, P: ≦ 0.15 wt%, S: ≦ 0.100 wt%, s
olAl: ≦ 0.150 wt%, N: ≦ 0.0150 wt
%, B: ≦ 0.0070 wt%, and one or more of Nb and Ti further contain ≦ 0.10 wt% as required, and the balance is composed of Fe and unavoidable elements. 2.0 to 15.0 g / m on the innermost layer of the surface corresponding to the side
⁽² ) Using a surface-treated steel plate coated with Sn or Sn alloy and having an outermost layer of a surface corresponding to the inner surface side of the lid coated with a resin film of 5 to 100 μm, the cross-sectional shape of the score blade tip is circular and its radius (R ) Is a score blade that is 0.040 to 0.300 mm, and is scored on both inside and outside of the lid.
Repair coating is not required, with Sn or Sn alloy remaining on the entire surface of the score groove on the outer surface of the lid and remaining without damaging the resin film on the entire surface of the score groove on the inner surface of the lid. Also an excellent easy-open lid manufacturing method. 3. C: ≦ 0.20 wt%, Si: ≦ 0.5 wt
%, Mn: ≦ 1.0 wt%, P: ≦ 0.15 wt%, S: ≦
0.100 wt%, solAl: ≤0.150 wt%, N:
≦ 0.0150 wt%, B: ≦ 0.0070 wt%, and one or more of Nb and Ti are ≦ 0.10 wt%
% If necessary, with the balance being Fe and unavoidable elements, and 2.0 to 15.0 g in the innermost layer on both the front and back surfaces.
/ M ² is an easy-open lid made of a surface-treated steel plate plated with Sn or a Sn alloy, having a score on the inner and outer surfaces of the lid, a score groove bottom shape in an arc shape, and a radius thereof. (R) is 0.040 to 0.300 mm, and Sn or Sn alloy remains on the entire surface of the score groove on the inner and outer surfaces of the lid. 4. C: ≦ 0.20 wt%, Si: ≦ 0.5 wt
%, Mn: ≦ 1.0 wt%, P: ≦ 0.15 wt%, S: ≦
0.100 wt%, solAl: ≤0.150 wt%, N:
≦ 0.0150 wt%, B: ≦ 0.0070 wt%, and one or more of Nb and Ti are ≦ 0.10 wt%
% If necessary, with the balance being Fe and unavoidable elements, and 2.0% in the innermost layer on the surface corresponding to the outer surface of the lid.
An lid made of a surface-treated steel sheet plated with Sn or Sn alloy of up to 15.0 g / m ² and having a resin coating of 5 to 100 μm on the outermost layer corresponding to the inner surface of the lid. An open lid having scores on the inner and outer surfaces of the lid, a score groove bottom shape having an arc shape, and a radius (R) of 0.
040 to 0.300 mm, Sn or Sn alloy remains on the entire surface of the score groove on the outer surface of the lid, and the resin film remains on the entire surface of the score groove on the inner surface of the lid without being damaged. Easy-open lid that does not require repair painting and has excellent flavor.