CN113825640B

CN113825640B - Plated steel sheet

Info

Publication number: CN113825640B
Application number: CN202080036690.XA
Authority: CN
Inventors: 二叶敬士; 后藤靖人; 柴尾史生; 久米久留巳; 横道拓哉; 宫田卓哉
Original assignee: Nippon Steel and Sumitomo Metal Corp
Current assignee: Nippon Steel Corp
Priority date: 2019-05-24
Filing date: 2020-05-22
Publication date: 2023-09-15
Anticipated expiration: 2040-05-22
Also published as: KR20210152501A; KR102592017B1; CN113825640A; WO2020241475A1

Abstract

The plated steel sheet according to one embodiment of the present application includes: the surface of the base steel plate is provided with a base texture, a galvanized layer formed on the surface of the base steel plate and provided with the base texture, and a coloring resin layer formed on the galvanized layer, wherein the galvanized layer is provided with a plating texture on the surface, the coloring resin layer contains a coloring agent, the plating texture comprises a plurality of convex parts and a plurality of concave parts, the three-dimensional average roughness Sas of the bottom of the concave parts is more than 200nm and less than 2000nm, dkmin multiplied by CK is less than 15.0, and (Dkmax-Dkmin) multiplied by CK is more than 1.0. Another aspect of the present application relates to a plated steel sheet comprising: the steel sheet comprises a base steel sheet, a galvanized layer formed on the surface of the base steel sheet, and a colored resin layer formed on the galvanized layer, wherein a texture extending in one direction is formed on the surface of the galvanized layer, the colored resin layer contains a colorant, the three-dimensional average roughness Saave 'is more than 5nm and less than 200nm, dkmin'. Times.CK 'is less than 15.0, and (Dkmax' -Dkmin '). Times.CK' is more than 1.0.

Description

Plated steel sheet

Technical Field

The present application relates to a plated steel sheet.

The present application claims priority based on japanese patent application publication nos. 2019-171166 of the japanese application at 9 month 20, 2019-171137 of the japanese application at 9 month 20, and 2019-098050 of the japanese application at 5 month 24, and references the contents thereof.

Background

Articles such as electric appliances, building materials, and vehicles sometimes require design properties. As a method for improving the design of an article, there are a method of coating the surface of an article and a method of attaching a film.

Recently, a tendency to use a material having a metallic texture is developed around natural europe and america. If the texture of metal is to be used, stainless steel plates and aluminum plates having excellent corrosion resistance even in the uncoated state are used as raw materials. Further, there are also commercially available stainless steel plates and aluminum plates having a surface with a texture represented by hairlines for the purpose of further developing the metallic feel of the stainless steel plates and aluminum plates. However, stainless steel plates and aluminum plates are expensive. Therefore, a low-cost material capable of replacing the stainless steel plate and the aluminum plate is required.

As a substitute material for such stainless steel plates and aluminum plates, a plated steel plate having a galvanized layer on the surface thereof has been studied. In the present specification, the zinc plating layer also includes a zinc alloy plating layer. The plated steel sheet has moderate corrosion resistance and excellent workability, similar to the stainless steel sheet and the aluminum sheet. Therefore, the plated steel sheet is suitable for applications such as electric appliances and building materials. Accordingly, various proposals have been made in the industry for the purpose of improving the design of plated steel sheets.

For example, japanese patent application laid-open No. 2006-124824 (patent document 1) discloses the following: after hairline finishing is performed on the galvanized steel sheet, a transparent resin film is formed on the surface of the galvanized layer on which hairlines are formed. Thus, the surface of the plating layer can be visually confirmed while maintaining corrosion resistance, and design is improved.

Further, japanese patent application laid-open No. 2013-536901 (patent document 2) discloses the following: the galvanized steel sheet is rolled, textures are formed on the surface of the galvanized layer, and then the surface of the galvanized layer is coated with an organic film (resin) with a surface roughness within a certain range. Thus, the surface of the plating layer can be visually confirmed while maintaining corrosion resistance, thereby improving design.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2006-124824

Patent document 2: japanese patent application laid-open No. 2013-536901

Disclosure of Invention

The invention aims to solve the technical problems

Recently, materials having a colored appearance while utilizing a metallic texture have been demanded. More specifically, there is a need for a plated steel sheet that has a colored appearance and in which the texture of the surface of the galvanized layer can be visually confirmed.

The invention aims at: provided is a plated steel sheet which has a colored appearance and in which the texture of the surface of a zinc plating layer can be visually confirmed.

Technical means for solving the technical problems

(1) A plated steel sheet according to an embodiment of the present invention includes:

a base metal steel plate having base metal textures on the surface,

A zinc plating layer formed on the surface of the base steel plate having the base texture, and a colored resin layer formed on the zinc plating layer,

the zinc-plated layer has a plating texture on its surface,

the colored resin layer contains a colorant,

the plating texture comprises a plurality of protrusions and a plurality of recesses,

when the rolling direction of the base steel sheet is defined as the 1 st direction and the direction perpendicular to the 1 st direction on the surface of the plated steel sheet is defined as the 2 nd direction, the plated steel sheet satisfies the following (a) to (C):

(A) Measuring a roughness profile in a range of 1000 [ mu ] m in length in the 2 nd direction of the plating texture, wherein when a lowest position in each of the recesses in the roughness profile obtained by the measurement is defined as a recess bottom point, among a plurality of recess bottom points of the roughness profile, 10 recess bottom points are sequentially designated from the lowest, a three-dimensional average roughness Sa of a minute region of 1 [ mu ] m×1 [ mu ] m centered on the designated recess bottom point is measured, and when an arithmetic average of the 10 three-dimensional average roughness Sa obtained by the measurement is defined as a recess bottom three-dimensional average roughness Sas, the recess bottom three-dimensional average roughness Sas is greater than 200nm and 2000nm or less,

(B) In the range of 100 μm in length in the 2 nd direction, a minimum thickness (μm) of the colored resin layer is defined as Dkmin, a content (area%) of the colorant in the colored resin layer is defined as CK, and when F1 is defined by formula (1), F1 is 15.0 or less,

F1＝DKmin×CK (1)

(C) In the range of the length of 100 μm in the 2 nd direction, the maximum thickness (μm) of the colored resin layer is defined as Dkmax, and when F2 is defined by the formula (2), the F2 is more than 1.0

F2＝(DKmax-DKmin)×CK (2)。

(2) The plated steel sheet according to the item (1), which may further satisfy the following (D):

(D) When a roughness profile having a length in the 2 nd direction of the plating texture is measured and a highest position of each of the convex portions in the roughness profile obtained by the measurement is defined as a convex portion peak, 10 convex portion peaks among a plurality of convex portion peaks of the roughness profile are sequentially designated from the highest, a three-dimensional average roughness Sa of a minute region of 1 μm×1 μm centered on the designated convex portion peak is measured, and an arithmetic average value of the 10 three-dimensional average roughness Sa obtained by the measurement is defined as a convex portion top three-dimensional average roughness Sas, the convex portion top three-dimensional average roughness Sah is greater than 5nm and 200nm or less.

(3) The plated steel sheet according to item (2), wherein,

a plurality of the convex portions and a plurality of the concave portions may extend in the 1 st direction,

a plurality of the convex portions and a plurality of the concave portions may be arranged in the 2 nd direction.

(4) The plated steel sheet according to item (3), wherein,

the base material texture may be hairline,

the plating texture may be a hairline,

the plated steel sheet may further satisfy the following (E) and (F):

(E) Defining the surface roughness Ra of the colored resin layer in the 1 st direction as Ra (CL), defining the surface roughness Ra of the colored resin layer in the 2 nd direction as Ra (CC), defining F3 by formula (3), wherein F3 is 1.10 or more,

F3＝Ra(CC)/Ra(CL) (3)

(F) When the surface roughness of the zinc-plated layer in the 2 nd direction is defined as Ra (MC), ra (MC) is 0.30 μm or more.

(5) The plated steel sheet according to any one of the items (1) to (4), wherein,

brightness L when the plated steel sheet is observed from the side of the colored resin layer ^* The (SCI) may be 45 or less.

(6) The plated steel sheet according to any one of the items (1) to (5), wherein,

f1 may be 13.5 or less.

(7) The plated steel sheet according to any one of the items (1) to (6), wherein,

f2 may be greater than 2.0.

(8) The plated steel sheet according to any one of the items (4) to (7), wherein,

the F3 may be 1.15 or more.

(9) The plated steel sheet according to any one of the items (1) to (8), wherein,

the exposure rate of the base steel sheet of the zinc coating layer may be less than 5%.

(10) The plated steel sheet according to item (2), wherein,

a plurality of the convex portions may be formed by grinding the surface of the zinc plating layer,

a plurality of the recesses may not be ground.

(11) Another aspect of the present invention relates to a plated steel sheet comprising:

a base steel plate,

A zinc-plated layer formed on the surface of the base steel sheet, and

a colored resin layer formed on the zinc plating layer, wherein,

the zinc coating layer has a texture extending in one direction on its surface,

the colored resin layer contains a colorant,

the plated steel sheet satisfies the following (A ') to (C'):

(a ') measuring a roughness profile having a length in a range of 1000 μm in a direction perpendicular to an extending direction of the texture, wherein 10 positions designated in order from a low height among the positions on the roughness profile obtained by the measurement are defined as concave bottom points, 10 positions designated in order from a high height among the positions on the roughness profile obtained by the measurement are defined as convex top points, a three-dimensional average roughness Sa ' of a minute region of 1 μm×1 μm centered on each concave bottom point and each convex top point is measured, and an arithmetic average value of the three-dimensional average roughness Sa ' obtained by the measurement is defined as three-dimensional average roughness Saave ', wherein the three-dimensional average roughness Saave ' is greater than 5nm and equal to or less than 200 nm;

(B ') in a range of a length of 100 [ mu ] m in a direction perpendicular to an extending direction of the texture, a minimum thickness ([ mu ] m) of the colored resin layer is defined as Dkmin', and a content (area%) of the colorant in the colored resin layer is defined as CK ', the formula (1'),

DKmin’×CK’≤15.0 (1’)；

(C ') in a range of a length of 100 [ mu ] m in a direction perpendicular to an extending direction of the texture, the maximum thickness ([ mu ] m) of the colored resin layer is defined as DKmax ', the formula (2 '),

(DKmax’-DKmin’)×CK’>1.0 (2’)。

(12) The plated steel sheet according to item (11), wherein,

the texture may be a hairline,

the plated steel sheet may satisfy the following (D ') and (E'):

(D ') when the surface roughness Ra of the colored resin layer in the extending direction of the texture is defined as Ra (CL)' and the surface roughness Ra of the colored resin layer in the direction perpendicular to the extending direction of the texture is defined as Ra (CC) 'the formula (3'),

Ra(CC)’≥Ra(CL)’×1.10 (3’)；

when the surface roughness of the zinc-plated layer in the direction perpendicular to the extending direction of the texture is defined as Ra (MC)' is 0.30 μm or more.

(13) The plated steel sheet according to item (11) or (12), wherein,

(14) The plated steel sheet according to any one of the items (1) to (13), wherein,

the colored resin layer may be a laminate resin layer,

the laminated resin layer may include a plurality of colored resin layers laminated in a normal direction to a surface of the base steel sheet,

in the plurality of colored resin layers, the sum of the product of the content (area%) of the colorant in the colored resin layer and the thickness (μm) of the colored resin layer may be 15.0 area%. Mu.m or less,

among the plurality of colored resin layers, a colored resin layer having a largest product of a content (area%) of the colorant in the colored resin layer and a thickness (μm) of the colored resin layer is defined as a most-concentrated colored resin layer, and a colored resin layer having a 2 nd largest product of a content of the colorant in the colored resin layer and a thickness of the colored resin layer is defined as a 2 nd-concentrated colored resin layer, wherein the content C of the colorant of the most-concentrated colored resin layer _1ST (area%), thickness D of the most dense colored resin layer _1ST (μm), the content C of the colorant of the 2 nd concentrated color colored resin layer _2ND (area%) and the thickness D of the 2 nd dense color colored resin layer _2ND (μm) may satisfy the formula (4),

1.00<(C _1ST ×D _1ST )/(C _2ND ×D _2ND )≤4.00 (4)。

(15) The plated steel sheet according to item (14), wherein,

the thickness of the laminated resin layer may be 10.0 μm or less.

(16) The plated steel sheet according to item (14) or (15), wherein,

the laminate resin layer may further comprise 1 or more transparent resin layers containing no colorant,

the laminated resin layer may be formed by laminating the plurality of colored resin layers and the 1 or more transparent resin layers.

ADVANTAGEOUS EFFECTS OF INVENTION

The galvanized steel sheet according to the invention has a colored appearance and the texture of the galvanized surface can be visually confirmed.

Drawings

FIG. 1A schematic view of a cross section perpendicular to the 1 st direction of a plated steel sheet according to embodiment 1.

FIG. 2 is a cross-sectional view of a plated steel sheet according to embodiment 1.

Fig. 3 is an enlarged view of the colored resin layer shown in fig. 2.

Fig. 4 is a plan view of a galvanized layer having hairlines as textures formed on the surface.

Fig. 5 is a view showing a roughness profile of a plating texture formed on the surface of a zinc plating layer.

Fig. 6A is a schematic view for explaining a bottom region of a minute recess in the surface of the zinc plating layer.

Fig. 6B is a schematic view for explaining a top region of a minute projection in the surface of the galvanized layer.

Fig. 7 is a cross-sectional view perpendicular to the 1 st direction at a portion near the surface of the zinc-plated layer.

Fig. 8 is a cross-sectional view perpendicular to the 1 st direction at a portion near the surface of the zinc-plating layer of embodiment 1.

Fig. 9 is a schematic view of a cross section perpendicular to the extending direction of the grain in the plated steel sheet of embodiment 2.

Fig. 10 is a cross-sectional view of a plated steel sheet according to embodiment 2.

Fig. 11 is an enlarged view of the colored resin layer shown in fig. 10.

Fig. 12 is a plan view of a galvanized layer having hairlines as textures formed on the surface.

Fig. 13 is a view showing a roughness profile of a texture formed on a surface of a galvanized layer.

Fig. 14A is a schematic view for explaining a minute recessed area in the surface of the zinc plating layer.

Fig. 14B is a schematic view for explaining a minute convex region in the surface of the zinc plating layer.

Fig. 15A is a schematic view of a cut section CS.

Fig. 15B is a schematic view of a cut section CS.

Fig. 16 is for illustration: in the case where the surface of the galvanized layer of the design galvanized steel sheet of the embodiment has hairlines as textures, a schematic diagram of a method for evaluating color unevenness is provided.

Fig. 17 is for illustration: in the case where the surface of the galvanized layer of the design galvanized steel sheet of the embodiment has hairlines as textures, a schematic diagram of a method of evaluating color fluctuation is provided.

Detailed description of the invention

(embodiment 1)

The present inventors studied a plated steel sheet having a colored appearance and a surface texture of a zinc plating layer (hereinafter referred to as a plated texture) that can be visually confirmed. As described in patent documents 1 and 2, a galvanized steel sheet having a transparent resin layer formed on a galvanized layer has been proposed. Accordingly, the present inventors have first tried to produce a galvanized steel sheet in which a resin layer formed on a galvanized layer is colored by including a colorant containing a pigment and/or a dye.

As a result, it was found that when a colorant was contained in the resin layer, depending on the conditions, the plating texture formed on the surface of the galvanized layer was not visually confirmed. Therefore, the present inventors have studied factors that affect visual confirmation of plating texture when a colorant is contained in a resin. As a result, the present inventors have found the following. In the following description, the rolling direction of the base steel sheet is defined as the 1 st direction RD. In addition, in the surface of the plated steel sheet, a direction perpendicular to the 1 st direction (width direction of the plated steel sheet) is defined as a 2 nd direction WD. The direction perpendicular to the 1 st direction RD and the 2 nd direction WD (thickness direction of the plated steel sheet) is defined as the 3 RD direction TD.

When a colored resin layer containing a colorant is formed on a galvanized layer having a plating texture formed on the surface, the content of the colorant in the colored resin layer and the thickness of the colored resin layer affect visual confirmation of the plating texture. Specifically, if the content of the colorant in the colored resin layer is too large, the plating texture may not be confirmed by the naked eye. Also, if the colored resin layer is too thick, the plating texture may not be confirmed by the naked eye.

In addition, in a cross section perpendicular to the 1 st direction RD, the thickness of the resin formed on the plating texture varies depending on the irregularities of the plating texture. Fig. 1 is a schematic view of a cross section perpendicular to the 1 st direction RD in the plated steel sheet of embodiment 1. Referring to fig. 1, a plated steel sheet 1 includes a base steel sheet 100, a zinc plating layer 10, and a colored resin layer 11. The base steel sheet 100 has a texture 100S on its surface. Hereinafter, the texture 100S is referred to as a base material texture 100S. The zinc plating layer 10 has a plating texture 10S on its surface. The plating texture 10S includes a plurality of Convex portions 10CO (Convex) and a plurality of concave portions 10RE (references). The convex portions 10CO and the concave portions 10RE are alternately arranged. In fig. 1, a plurality of convex portions 10CO and a plurality of concave portions 10RE are alternately arranged in the 2 nd direction WD.

The colored resin layer 11 is formed on the surface of the zinc-plated layer 10. Therefore, although the surface 11S of the colored resin layer 11 reflects the uneven pattern (the shape of the concave portion 10RE and the convex portion 10 CO) of the plating texture 10S to some extent, it is flatter than the plating texture 10S. Specifically, in the surface 11S of the colored resin layer 11, the convex portion 11CO is formed at a portion corresponding to the convex portion 10CO of the plating texture 10S. The height of the convex portion 11CO is lower than the height of the convex portion 10 CO. That is, the surface 11S of the colored resin layer 11 is more planarized than the surface of the plating texture 10S.

Here, in the range where the length in the 2 nd direction WD is 100 μm, the maximum thickness (μm) of the colored resin layer 11 is defined as DKmax. Further, the minimum thickness (μm) of the colored resin layer 11 was defined as DKmin. In order to make the plated texture 10S visually identifiable even when the colored resin layer 11 is colored, it is necessary to limit the colorant content CK (area%) in the colored resin layer 11 and the thickness of the colored resin layer 11 to some extent as described above. Also, under the limitation thereof, the difference between the maximum thickness DKmax and the minimum thickness DKmin of the colored resin layer 11 is reflected in the difference in brightness that the plated texture can be visually confirmed. Specifically, by making the difference between the maximum thickness DKma x and the minimum thickness DKmin of the colored resin layer 11 large to a certain extent, the concave portion 10RE and the convex portion 10CO of the plated texture 10S have a difference in brightness. As a result, even when the colored resin layer 11 is formed, the plating texture 10S can be visually confirmed.

Further, the adhesion of the colored resin layer 11 to the galvanized layer 10 is preferably high. Accordingly, the present inventors studied a method of improving the adhesion of the colored resin layer 11 to the galvanized layer 10. The result shows that: by roughening the surface roughness of the convex portion 10CO and concave portion 10RE of the plating texture 10S, particularly in the minute region of the concave portion 10RE, to a certain extent (specifically, by making the three-dimensional average roughness Sas of the concave portion bottom portion described later larger than 200nm and 2000nm or less), the adhesion of the colored resin layer 11 to the galvanized layer 10 can be improved.

Based on the above findings, the present inventors have found that a plated steel sheet having a colored appearance, a surface plated with a zinc coating layer having a visually identifiable plated texture, and excellent adhesion of a colored resin layer can be produced by the following (a) to (C): the surface roughness of the minute areas in the concave portion 10RE in the convex portion 10CO and the concave portion 10RE of the plating texture 10S is roughened to a certain extent, (B) the thickness and the colorant content of the colored resin layer 11 are adjusted, and (C) the difference between the maximum thickness DKmax and the minimum thickness DKmin of the colored resin layer 11 in the cross section perpendicular to the 1 st direction is adjusted to a certain extent.

The plated steel sheet of embodiment 1 completed based on the above findings has the following constitution:

[1] the plated steel sheet of (1) comprises:

a base metal steel plate having base metal textures on the surface,

the zinc-plated layer has a plating texture on its surface,

the colored resin layer contains a colorant,

(A) When a roughness profile having a length in the 2 nd direction of the plating texture within a range of 1000 μm is measured, and a lowest position in each of the recesses in the roughness profile obtained by the measurement is defined as a recess bottom point, among a plurality of recess bottom points in the roughness profile, 10 recess bottom points are sequentially designated from the lowest, a three-dimensional average roughness Sa of a minute region of 1 μm×1 μm centered on the designated recess bottom point is measured, and an arithmetic average value of the 10 three-dimensional average roughness Sa obtained by the measurement is defined as a recess bottom three-dimensional average roughness Sas, the recess bottom three-dimensional average roughness Sas is greater than 200nm and 2000nm or less.

(B) In the range where the length in the 2 nd direction is 100 μm, the minimum thickness (μm) of the colored resin layer is defined as DKmin, the content (area%) of the colorant in the colored resin layer is defined as CK, and when F1 is defined as formula (1), the F1 is 15.0 or less.

F1＝DKmin×CK (1)

(C) In the range of the length in the 2 nd direction of 100 μm, the maximum thickness (μm) of the colored resin layer is defined as DKmax, and when F2 is defined by formula (2), the F2 is greater than 1.0.

F2＝(DKmax-DKmin)×CK (2)

[2] The plated steel sheet according to [1], which may further satisfy the following (D):

The roughness of the plated texture can have an effect on visual confirmation of the plated texture. When a plating texture is formed on the surface of the zinc plating layer, not only the irregularities of the plating texture but also minute irregularities (roughness) due to the crystallization of zinc plating are present on the surface of the plating texture. If the micro irregularities caused by the zinc plating crystallization are small, the diffuse reflection of light due to the micro irregularities caused by the zinc plating crystallization is suppressed. In this case, the gloss of the plating texture is improved, and whitening of the plating texture is suppressed. In the plated steel sheet of [2], the roughness of the plating texture at the microscopic region of the concave portion is kept at 200nm or more, and the roughness of the convex portion at the microscopic region is suppressed to 200nm or less. Therefore, the adhesion of the colored resin layer can be maintained by the concave portions of the plating texture, and the visibility of the plating texture can be further improved by the convex portions.

[3] The plated steel sheet according to [2], wherein,

[4] The plated steel sheet according to [3], wherein,

The base material texture may be hairline,

the plating texture may be a hairline,

the plated steel sheet may further satisfy the following (E) and (F):

(E) The surface roughness Ra of the colored resin layer in the 1 st direction is defined as Ra (CL), the surface roughness Ra of the colored resin layer in the 2 nd direction is defined as Ra (CC), and when F3 is defined by formula (3), the F3 is 1.10 or more.

F3＝Ra(CC)/Ra(CL) (3)

[5] The steel sheet plated according to any one of [1] to [4], wherein,

[6] The steel sheet plated according to any one of [1] to [5], wherein,

f1 may be 13.5 or less.

[7] The steel sheet plated according to any one of [1] to [6], wherein,

f2 may be greater than 2.0.

[8] The steel sheet plated according to any one of [4] to [7], wherein,

the F3 may be 1.15 or more.

[9] The steel sheet plated according to any one of [1] to [8], wherein,

[10] The plated steel sheet according to [2], wherein,

a plurality of the recesses may not be ground.

Hereinafter, the plated steel sheet of embodiment 1 will be described in detail.

[ concerning plated Steel sheet 1]

Fig. 2 is a cross-sectional view of plated steel sheet 1 according to embodiment 1. Referring to fig. 2, a plated steel sheet 1 according to embodiment 1 includes: a base steel sheet 100, a zinc plating layer 10, and a colored resin layer 11. The zinc plating layer 10 is formed on the base material texture 100S on the surface of the base material steel sheet 100. The colored resin layer 11 is formed on the surface (texture) 10S of the zinc-plated layer 10. The zinc plating layer 10 is disposed between the base steel sheet 100 and the colored resin layer 11. Hereinafter, the base steel sheet 100, the zinc coating layer 10, and the colored resin layer 11 will be described.

[ concerning base material Steel sheet 100]

The base steel sheet 100 may be a known steel sheet applicable to a plated steel sheet, depending on the mechanical properties (e.g., tensile strength, workability, etc.) required for the plated steel sheet to be produced. For example, as the base steel sheet 100, a steel sheet used for electric appliances or a steel sheet used for vehicle outer panels may be used. The base steel sheet 100 may be a hot-rolled steel sheet or a cold-rolled steel sheet.

A texture 100S (base material texture 100S) is formed on the surface of the base material steel sheet 100. That is, the base steel sheet 100 has a texture 100S (base texture 100S) on its surface. The plating texture 10S described later may be formed along the base material texture 100S. In this case, the pattern of the plating texture 10S is similar to the pattern of the base material texture 100S. For example, when the base material texture 100S is matted, the plating texture 10S is matted. When the base material texture 100S is hairline, the plated texture 10S is hairline. On the other hand, the base material texture 100S may have a different pattern from the plating texture 10S. For example, the base material texture 100S may be matt and the plated texture 10S may be hairline.

[ concerning Zinc coating 10]

The zinc plating layer 10 is formed on the surface of the base steel sheet 100. In embodiment 1, the zinc plating layer 10 is disposed between the base steel sheet 100 and the colored resin layer 11. The zinc plating layer 10 is formed by a known zinc plating treatment method. Specifically, the zinc plating layer 10 is formed by, for example, an electroplating method. In the present specification, the zinc plating layer 10 also includes a zinc alloy plating layer.

The zinc coating layer 10 may have a known chemical composition. For example, the Zn content in the chemical composition of the zinc plating layer 10 may be 65% or more by mass%. If the Zn content is 65% by mass or more, the sacrificial corrosion prevention function can be significantly exhibited, and the corrosion resistance of the plated steel sheet 1 is significantly improved. The lower limit of the Zn content in the chemical composition of the zinc-plated layer 10 is preferably 70%, more preferably 80%.

The chemical composition of the zinc-plated layer 10 preferably further contains 1 element or 2 elements or more selected from Al, co, cr, cu, fe, ni, P, si, sn, mg, mn, mo, V, W, zr in addition to Zn. Further, when the zinc plating layer 10 is a zinc plating layer, the chemical composition is more preferably at least 1 element selected from Fe, ni and Co in a total amount of 5 to 20 mass%. Further, the chemical composition when the galvanized layer 10 is a hot dip galvanized layer further preferably contains at least 1 element or more selected from Mg, al, and Si in a total amount of 5 to 20 mass%. In these cases above, the galvanized layer 10 further exhibits excellent corrosion resistance.

The zinc coating layer 10 may contain impurities. Here, the impurities refer to impurities mixed in raw materials or mixed in a manufacturing process. The impurity is Ti, B, S, N, C, nb, pb, cd, ca, pb, Y, la, ce, sr, sb, O, F, cl, zr, ag, W, H, for example. The total content of impurities in the chemical composition of the zinc plating layer 10 is preferably 1% or less.

As for the chemical composition of the galvanized layer 10, for example, it can be determined by the following method: the colored resin layer 11 of the plated steel sheet 1 is removed with a stripping agent such as a solvent that does not attack the galvanized layer 10, a stripping agent (remover) (for example, trade name: neo reverse S-701 manufactured by trichromatic chemical Co., ltd.). Then, the zinc plating layer 10 is dissolved using hydrochloric acid to which an inhibitor is added. The solution was subjected to ICP analysis using an ICP (Inductively Coupled Plasma: inductively coupled plasma) emission spectrometry device to determine the Zn content. If the obtained Zn content is 65% or more, it is determined that the plating layer to be measured is the zinc plating layer 10.

[ concerning the amount of adhesion of the galvanized layer 10 ]

The amount of the zinc plating layer 10 to be adhered is not particularly limited, and a known amount may be sufficient. The preferable adhesion amount of the zinc plating layer 10 is 5.0 to 120.0g/m ² . If the adhesion amount of the zinc plating layer 10 is 5.0g/m ² As described above, when the plating texture described later is applied to the galvanized layer 10, exposure of the base steel sheet (base steel sheet 100) can be suppressed. The lower limit of the adhesion amount of the zinc plating layer 10 is more preferably 7.0g/m ² Further preferably 10.0g/m ² . The upper limit of the adhering amount of the zinc plating layer 10 is not particularly limited. From the economical point of view, in the case of the zinc plating layer 10 formed by the plating method, the upper limit of the adhesion amount is preferably 40.0gm ² More preferably, the upper limit is 35.0g/m ² Further preferably 30.0g/m ² 。

[ concerning the colored resin layer 11]

The colored resin layer 11 is formed on the surface (plating texture) 10S of the zinc-plating layer 10. Fig. 3 is an enlarged view of the colored resin layer 11 shown in fig. 2. Referring to fig. 3, the colored resin layer 11 includes a resin 31 and a colorant 32. The colorant 32 is contained in the resin 31. Hereinafter, the resin 31 and the colorant 32 will be described.

[ concerning resin 31]

The resin 31 is a resin having light transmittance. In embodiment 1, the term "resin having light transmittance" means that when the plated steel sheet 1 having the colored resin layer 11 containing the colorant 32 and the resin 31 is placed in an environment corresponding to sunlight in the morning of a sunny day (illuminance of about 65000 lux), the plated texture 10S of the galvanized layer 10 can be visually confirmed. The resin 31 functions as an adhesive for fixing the colorant 32.

The resin 31 is not particularly limited as long as it has the above-defined light transmittance, and a known natural resin or a known synthetic resin may be used. The resin 31 may be, for example, 1 or 2 or more selected from epoxy resin, urethane resin, polyester resin, phenol resin, polyether sulfone resin, melamine alkyd resin, acrylic resin, polyamide resin, polyimide resin, polysiloxane resin, polyvinyl acetate resin, polyolefin resin, polystyrene resin, vinyl chloride resin, and vinyl acetate resin.

[ concerning colorant 32]

The colorant 32 is contained in the resin 31 to color the colored resin layer 11. Colorant 32 is a well-known colorant. The colorant 32 has a chromatic color. The chromatic color is a color having attributes of hue, lightness, and chroma. The colorant 32 contains, for example, 1 or more selected from inorganic pigments, organic pigments, and dyes. The colorant 32 is more preferably a pigment (inorganic pigment and/or organic pigment) from the viewpoint of durability against ultraviolet rays.

If the colorant 32 is an inorganic pigment, the colorant 32 is, for example, a neutral precipitated pigment (sulfate, carbonate, etc.) and/or a fired pigment (metal sulfide, metal oxide, polyvalent metal composite oxide, etc.). If the colorant 32 is an organic pigment, the colorant 32 is, for example, 1 or more selected from the group consisting of chlorine pigments, azo pigments (dissolved azo lake pigments, insoluble azo pigments, etc.), acid-condensed pigments, polycyclic pigments (phthalocyanine pigments, indigo pigments, quinacridone pigments, anthraquinone pigments, etc.), and metal complex pigments (azo chelate pigments, transition metal complex pigments, etc.). If the colorant 32 is a dye, the colorant 32 is, for example, 1 or more selected from azo dyes, indigo dyes, anthraquinone dyes, sulfur dyes, and Carbonium dyes (Carbonium dyes).

The color of the colorant 32 is not particularly limited. The colorant 32 is, for example, carbon black (C), iron black (Fe ₃ O ₄ ) Black, etc. However, the colorant 32 is not limited to black, and may be other colors of colorant 32 (white, mauve, yellow, green-blue, red, orange, yellow, green, cyan, blue, violet, etc.).

If the colorant 32 is a pigment, the particle size is not particularly limited. When the colorant 32 is a pigment, the maximum value of the primary particle diameter is, for example, 3nm to 1000nm.

[ concerning the plating texture 10S formed on the surface of the galvanized layer 10 ]

A plating texture 10S is formed on the surface of the zinc plating layer 10 of the plated steel sheet 1. That is, the galvanized layer 10 of the plated steel sheet 1 has a plating texture 10S on its surface. In embodiment 1, the "texture" refers to a concave-convex pattern formed on the surface of the base steel sheet 100 and/or the surface of the zinc coating layer 10 by a physical or chemical technique. That is, the texture (base material texture 100S, plating texture 10S) has a plurality of convex portions and a plurality of concave portions. The convex portion and the concave portion may or may not extend in one direction. The texture is, for example, matt, hairline. Preferably the texture is hairline. The hairline is a linear concave-convex pattern extending in one direction.

[ case where the plating texture 10S is hairline ]

Fig. 4 is a plan view of the galvanized layer 10 having hairlines formed on the surface as the plating textures 10S. Referring to fig. 4, hairline 10S is a straight concave-convex pattern formed on the surface of galvanized layer 10. The hairline 10S includes a plurality of grooves 10L extending in the 1 st direction. The extending directions of the plurality of grooves 10L of the hairline 10S are substantially the same direction. The substantially same direction here means that 90% or more of the grooves 10L adjacent to each other form an angle of less than ±5° in the 2 nd direction WD aligned perpendicular to the extending direction of the grooves 10L of the hairline 10S when the galvanized layer 10 is viewed from the thickness direction TD (i.e., as in the plan view of fig. 4).

[ concerning the requirements (A) to (C) ]

The plated steel sheet 1 of embodiment 1 having the above-described configuration further satisfies the following (a) to (C).

Element (a):

the roughness profile of the plating texture 10S in the 2 nd direction WD in the length of 1000 μm is measured, the lowest position of each recess 10RE in the measured roughness profile is defined as a recess bottom point, 10 recess bottom points are designated in order from the lowest among a plurality of recess bottom points of the roughness profile, the three-dimensional average roughness Sa of a minute region of 1 μm×1 μm centered on the designated recess bottom point is measured, and when the arithmetic average of the measured 10 three-dimensional average roughness Sa is defined as a recess bottom three-dimensional average roughness Sas, the recess bottom three-dimensional average roughness Sas is greater than 200nm and 2000nm or less.

Element (B):

in the range where the length in the 2 nd direction WD is 100 μm, the minimum thickness (μm) of the colored resin layer 11 is defined as DKmin, the content (area%) of the colorant 32 in the colored resin layer 11 is defined as CK, and when F1 is defined as formula (1), F1 is 15.0 or less.

F1＝DKmin×CK (1)

Element (C):

in the range where the length in the 2 nd direction WD is 100 μm, when F2 is defined by formula (2) with the maximum thickness (μm) of the colored resin layer 11 defined as DKmax, F2 is greater than 1.0.

F2＝(DKmax-DKmin)×CK (2)

The following describes each element in detail.

[ surface roughness of the texture

Fig. 5 is a view showing a roughness profile of the plating texture 10S formed on the surface of the zinc plating layer 10. Referring to fig. 5, an arbitrary length of 1000 μm is selected in the 2 nd direction WD of the plated texture 10S. The roughness profile of the plated texture 10S was measured over a selected length of 1000 μm. The resulting roughness profile is assumed to be the shape as in fig. 5.

[ regarding the three-dimensional average roughness Sas of the bottom of the recess ]

Attention is paid to each concave portion 10RE in the measured roughness profile. In each recess 10RE, the position at which the height is lowest is defined as a recess bottom point PRE. Among a plurality of recess bottom points PRE in the roughness profile of a range of 1000 μm in length, 10 recess bottom points PRE1, PRE2, …, PRE10 are designated in order from low to high from the lowest recess bottom point PRE 1.

As shown in fig. 6A, in a plan view of the surface of the zinc plating layer 10, a 1 μm×1 μm minute concave portion bottom region 200 centered on each concave portion bottom point PREk (k is 1 to 10) defined is designated. In fig. 6A, the longitudinal direction of the minute concave portion bottom region 200 is parallel to the extending direction RD of the plating texture 10S, and the lateral direction of the minute concave portion bottom region 200 is parallel to the width direction WD. However, the sides of the micro concave portion bottom region 200 may not be parallel to the extending direction RD or the width direction WD, as long as the surfaces include the extending direction RD and the width direction WD.

In each of the 10 minute recess bottom regions 200 specified by the above method, the three-dimensional average roughness Sa was measured. The three-dimensional average roughness Sa is an arithmetic average roughness specified in ISO 25178, which expands Ra (arithmetic average roughness of a line) specified in JIS B0601 (2013) to a plane. The arithmetic average of the 10 three-dimensional average roughness Sa obtained by the measurement was defined as the recess bottom three-dimensional average roughness Sas.

[ regarding the three-dimensional average roughness Sah of the top of the convex portion ]

Referring to fig. 5, attention is paid to each convex portion 10CO in the roughness profile of the plating texture 10S in the range of 1000 μm in any length in the 2 nd direction WD. In each convex portion 10CO, the highest position is defined as a convex portion apex PCO. Of the plurality of convex portion apexes PCO in the roughness profile having a length in the range of 1000 μm, 10 convex portion apexes PCO1, PCO2, …, PCO10 are designated in order from highest to lowest from the highest convex portion apex PCO 1.

As shown in fig. 6B, in a plan view of the surface of the zinc plating layer 10, a 1 μm×1 μm minute convex top region 300 centered on each of the defined convex portion vertices PCOk (k is 1 to 10) is designated. In fig. 6B, the longitudinal direction of the minute convex top region 300 is parallel to the extending direction RD of the plating texture 10S, and the lateral direction of the minute convex top region 300 is parallel to the width direction WD. However, the sides of the fine convex top region 300 may not be parallel to the extending direction RD or the width direction WD, as long as the fine convex top region 300 includes the extending direction RD and the width direction WD.

In each of the 10 minute convex top regions 300 specified by the above method, the three-dimensional average roughness Sa was measured. The three-dimensional average roughness Sa is an arithmetic average roughness specified in ISO 25178, which expands Ra (arithmetic average roughness of a line) specified in JIS B0601 (2013) to a plane. The arithmetic average of the measured 10 three-dimensional average roughness Sa is defined as the convex top three-dimensional average roughness Sah.

[ concerning the requirement (A) ]

The three-dimensional average roughness Sas of the bottom of the concave portion obtained by the above definition is more than 200nm and not more than 2000nm (element (A)). This roughness can be considered to be based on zinc-plated crystals. Therefore, the plurality of recesses of the zinc plating may not be ground. In the irregularities of the plating texture 10S, the three-dimensional average roughness Sas of the recess bottom is roughened at least to some extent, and if it is more than 200nm and 2000nm or less, the adhesion of the colored resin layer 11 to the zinc plating layer 10 can be improved. The lower limit of the three-dimensional average roughness Sas of the recess bottom is preferably 250nm, more preferably 300nm. The upper limit of the three-dimensional average roughness Sas of the recess bottom is preferably 1500nm, more preferably 1000nm, and still more preferably 800nm.

In the plating texture 10S, the value of the convex top three-dimensional average roughness Sah is not particularly limited if at least the concave bottom three-dimensional average roughness Sas is greater than 200nm and 2000nm or less. The three-dimensional average roughness Sah of the top of the convex portion is, for example, 2000nm or less. Since Sah is not limited, the plurality of convex portions may be formed by polishing the surface of the galvanized layer, or may not be polished. The shape of the irregularities of the plating texture 10S is not particularly limited.

Fig. 7 is a cross-sectional view perpendicular to the 1 st direction RD at a portion near the surface of the zinc-plated layer 10. Referring to fig. 7, in the concave portion 10RE and the convex portion 10CO of the plating texture 10S formed on the surface of the zinc plating layer 10, nano-scale minute irregularities (minute concave portion SRE and minute convex portion SCO) caused by plating crystallization exist in the surface of the concave portion 10RE and the surface of the convex portion 10CO before polishing. In this case, the concave bottom three-dimensional average roughness Sas and the convex top three-dimensional average roughness Sah are both larger than 200nm and not larger than 2000 nm.

[ concerning the requirement (B) ]

Referring to fig. 1, attention is paid to a cross section of an arbitrary length in a range of 100 μm in a 2 nd direction WD perpendicular to a 1 st direction RD of a plated texture 10S. The cross section (fig. 1) of the range of 100 μm in length is defined as the observation cross section. In the observation section, the minimum thickness among the thicknesses of the colored resin layers 11 is defined as DKmin (μ). In the observation section, the maximum thickness among the thicknesses of the colored resin layers 11 is defined as DKmax (μm).

Further, in the observation section, the content (area%) of the colorant in the colored resin layer 11 is defined as CK. As described above, in the present specification, the colorant content CK is expressed as an area ratio (area%) of the colorant in the observation section.

Here, F1 is defined by formula (1).

F1＝DKmin×CK (1)

In this case, F1 is 15.0 or less.

F1 is an index of the coloring concentration of the colored resin layer 11. If F1 is greater than 15.0, the thickness of the colored resin layer 11 is too thick or the colorant content CK is too large. In this case, the coloring of the colored resin layer 11 is too intense, and the plating texture 10S of the zinc plating layer 10 is difficult to be visually confirmed. If F1 is 15.0 or less, the plating texture 10S on the surface of the zinc-plated layer 10 can be sufficiently visually confirmed while having the appearance of being colored by the colored resin layer 11, provided that the requirements (a) and (C) are satisfied. The upper limit of F1 is preferably 14.0, more preferably 13.5, still more preferably 13.0, and still more preferably 12.5. The lower limit of F1 is not particularly limited. The lower limit of F1 is, for example, 4.0.

The thickness of the colored resin layer 11 was measured by the following method. A sample having a cross section perpendicular to the 1 st direction RD of the plated texture 10S on the surface was collected. The observation section of the sample was observed with a Scanning Electron Microscope (SEM) in a range of 100 μm in length in the 2 nd direction WD in a 2000-fold reflected electron image (BSE). In observation with a Scanning Electron Microscope (SEM) reflected electron image (BSE), the base steel sheet 100, the galvanized layer 10, and the colored resin layer 11 can be easily distinguished by contrast (contrast). In the observation section, the thickness of the colored resin layer 11 was measured at a pitch of 0.5 μm in the 2 nd direction WD. In the measured thickness, the minimum thickness is defined as the minimum thickness Dkmin (μm). In the measured thickness, the maximum thickness is defined as the maximum thickness Dkmax (μm). If it is necessary to determine whether the resin layer 11 is colored (that is, whether a colorant is contained in the resin), it is possible to determine whether the resin layer 11 is colored by TEM observation described later.

The colorant content CK (area%) in the colored resin layer 11 was determined by the following method. A sample having a cross section perpendicular to the 1 st direction RD of the plated texture 10S on the surface was collected. In the sample, a cross section perpendicular to the 1 st direction RD of the plated texture 10S was defined as an observation plane. From the sample, a film sample capable of observing the colored resin layer 11 and the galvanized layer 10 on the observation surface was prepared using a Focused Ion Beam apparatus (FIB). The thickness of the film sample was set to 50 to 200nm. The length of the prepared film sample in the direction perpendicular to the thickness direction of the colored resin layer 11 (i.e., the 2 nd direction WD) was 3 μm, and the view having the length including the entire colored resin layer in the thickness direction of the colored resin layer (i.e., the 3 rd direction TD) was observed using a transmission electron microscope (TEM: transmission Electron Microscope). In TEM observation, the resin 31 and the colorant 32 in the colored resin layer 11 can be identified by contrast. The total area A1 (μm) of the plurality of colorants in the colored resin layer 11 in the visual field was obtained ² ). And the area (. Mu.m) of the colored resin layer 11 in the visual field was determined ² ). Based on the obtained total area A1 and the surfaceThe product A0 was obtained by determining the colorant content (area%) in the colored resin layer 11 by the following formula.

CK＝A1/A0×100

[ concerning requirement (C) ]

In an observation cross section of a range of 100 μm in length in the 2 nd direction WD of the plated texture 10S, wherein the observation cross section is a cross section perpendicular to the 1 st direction RD of the plated texture 10S, F2 is defined by formula (2).

F2＝(DKmax-DKmin)×CK (2)

At this time, F2 is greater than 1.0.

F2 is an index of contrast of brightness in the colored resin layer 11. If F2 is 1.0 or less, the contrast of brightness in the colored resin layer 11 is low. In this case, the contrast of the brightness of the colored resin layer 11 cannot be sufficiently used for visual confirmation of the plated texture 10S. Therefore, the plating texture 10S under the colored resin layer 11 is difficult to be visually confirmed.

If F2 is higher than 1.0, the contrast of brightness in the colored resin layer 11 is sufficiently high. In this case, the contrast of the brightness of the colored resin layer 11 can be sufficiently used for visual confirmation of the plating texture 10S. As a result, the plated texture 10S under the colored resin layer 11 can be sufficiently visually confirmed on the premise that the requirement (a) and the requirement (B) are satisfied.

The preferable lower limit of F2 is 2.0 or more than 2.0, more preferably 2.2, and still more preferably 2.4. The upper limit of F2 is not particularly limited. The upper limit of F2 is, for example, 15.0.

[ brightness L when the plated steel sheet is viewed from the colored resin layer side ] ^* (SCI)]

The brightness of the entire surface of the plated steel sheet 1 according to embodiment 1 is not particularly specified as long as the above-described requirements such as F2, which is an index of the brightness in the concave portion and the convex portion, are satisfied. Therefore, the brightness L when the plated steel sheet is observed from the side of the colored resin layer ^* The upper and lower limit values of (SCI) are not particularly limited. On the other hand, the brightness L when the plated steel sheet is observed from the side of the colored resin layer ^* The (SCI) may be 45 or less. Brightness L of plated steel sheet ^* The lower the (SCI), the more the blackness of the plated steel sheet observed with naked eyes increases. At the position ofIn a usual plated steel sheet, if the brightness L of the surface thereof is reduced ^* When (SCI) is 45 or less, the plating texture becomes difficult to be visually confirmed. On the other hand, since the plated steel sheet 1 of embodiment 1 satisfies the above-mentioned requirements (a) to (C), the brightness L when the plated steel sheet is observed from the colored resin layer side ^* The (SCI) was 45 or less, and the texture of the surface of the zinc plating layer was also visually confirmed.

Brightness L ^* (SCI) is the brightness obtained by measuring the SCI method. The SCI method is also referred to as a method involving specular reflection light, and means a method of measuring color without removing specular reflection light. The brightness measurement method according to the SCI method is specified in JIS Z8722 (2009). In the SCI system, since measurement is performed without removing specular reflection light, the color of an actual object (so-called object color) is measured. CIELAB indicates that the color is a uniform color space defined in JIS Z8781 (2013). The CIEL AB has 3 coordinates of L ^* Value, a ^* Value, b ^* The value represents. L (L) ^* The value represents brightness and is represented by 0 to 100. L (L) ^* The value of 0 represents black, L ^* A value of 100 indicates a diffuse reflection of white.

[ concerning the thickness of the colored resin layer 11 ]

In plated steel sheet 1 of embodiment 1, the average thickness of colored resin layer 11 is preferably 10.0 μm or less. If the thickness of the colored resin layer 11 exceeds 10.0 μm, it is easy to smooth (Leveling) only the colored resin layer 11, and the difference between the impression of reflection at the surface of the colored resin layer 11 and the impression of the plated texture 10S that can be confirmed with the naked eye becomes large. In this case, the metallic feeling of the plated steel sheet 1 is reduced. If the average thickness of the colored resin layer 11 is 10.0 μm or less, the plated texture 10S of the zinc plating layer 10 can be visually confirmed and the metallic feel can be sufficiently improved on the premise that all of the above-described requirements (a) to (C) are satisfied. The upper limit of the average thickness of the colored resin layer 11 is more preferably 9.0 μm, and still more preferably 8.0 μm.

Further, the preferable lower limit of the average thickness of the colored resin layer 11 is 0.5 μm. If the average thickness of the colored resin layer 11 is 0.5 μm or more, the corrosion resistance is further improved. The lower limit of the average thickness of the colored resin layer 11 is more preferably 0.7 μm, still more preferably 1.0 μm, still more preferably 2.0 μm, still more preferably 3.0 μm.

The average thickness of the colored resin layer 11 was measured by the following method. The arithmetic average value of the thicknesses measured at 0.5 μm intervals in the 2 nd direction WD in the above-mentioned observation section is defined as the average thickness (μm) of the colored resin layer 11.

[ concerning requirement (D) ]

In the plated steel sheet 1 of embodiment 1, the three-dimensional average roughness Sah of the top of the convex portion is preferably greater than 5nm and 200nm or less (element (D)).

Referring to fig. 7, in the concave portion 10RE and the convex portion 10CO of the plating texture 10S formed on the surface of the zinc plating layer 10, nano-scale minute irregularities (minute concave portion SRE and minute convex portion SCO) caused by plating crystallization exist in the surface of the concave portion 10RE and the surface of the convex portion 10CO before polishing. That is, the roughness of the minute irregularities (minute concave portion SRE and minute convex portion SCO) in the convex portion 10CO is as rough as the roughness of the minute irregularities (minute concave portion SRE and minute convex portion SCO) in the concave portion 10 RE. Therefore, in the convex portion 10CO, light is diffusely reflected by the minute irregularities, as in the concave portion 10 RE.

Therefore, in the element (D), the convex portion top three-dimensional average roughness Sah is set smaller than the concave portion bottom three-dimensional average roughness Sas. Specifically, as described above, the three-dimensional average roughness Sah of the convex top may be set to be greater than 5nm and not greater than 200nm with respect to the three-dimensional average roughness Sas of the concave bottom. In this case, light is easily diffusely reflected in the concave portion 10RE, whereas the roughness in the convex portion 10CO is lower than that of the concave portion 10RE, and light is not easily diffusely reflected. Therefore, in the plating texture 10S of the zinc plating layer 10, the convex portion 10CO becomes a state that is easily confirmed by the naked eye. For example, as shown in fig. 8, the tip of the convex portion 10CO is polished so that the convex portion 10CO has a trapezoidal shape. As a result, the roughness of the minute irregularities (minute concave portion SRE and minute convex portion SCO) in the convex portion 10CO can be made smaller than the roughness of the minute irregularities (minute concave portion SRE and minute convex portion SCO) in the concave portion 10 RE.

When the three-dimensional average roughness Sah of the top of the convex portion is 200nm or less, diffuse reflection of light near the peak of the convex portion can be suppressed. In this case, in the plated steel sheet 1 of embodiment 1 having the colored resin layer 11, the plated texture 10S is further easily confirmed by the naked eye. It is preferable that the smaller the three-dimensional average roughness Sah of the convex portion top is. However, it is extremely difficult to set the three-dimensional average roughness Sah of the top of the convex portion to 5nm or less. Therefore, in embodiment 1, the three-dimensional average roughness Sah of the top of the convex portion is greater than 5nm and 200nm or less. The upper limit of the three-dimensional average roughness Sah at the top of the convex portion is preferably 190nm, more preferably 180nm, and still more preferably 170nm.

[ other morphology of colored resin layer 11 ]

In order to impart corrosion resistance, slidability, conductivity, and the like to the colored resin layer 11, the colored resin layer 11 of the plated steel sheet 1 of embodiment 1 may further contain an additive. Examples of the additives for imparting corrosion resistance include well-known rust inhibitors and inhibitors. Additives for imparting slidability are, for example, well-known waxes and beads. The additive for imparting conductivity is, for example, a known conductive agent.

[ regarding the surface shape of the colored resin layer 11 (regarding the element (E)) when the plating texture 10S is hairline ]

The colored resin layer 11 may have a surface shape as described in detail below due to the kind of plating texture 10S formed on the surface of the zinc plating layer 10 as the lower layer.

Here, the plating texture 10S is assumed to be hairline. The surface roughness Ra of the colored resin layer 11 in the 1 st direction RD of the plating texture 10S is defined as Ra (CL). The surface roughness Ra of the colored resin layer 11 in the 2 nd direction WD of the plating texture 10S is defined as Ra (CC). And, F3 is defined by formula (3).

F3＝Ra(CC)/Ra(CL)

In this case, F3 may be 1.10 or more.

F3 is an index related to the metallic feel of the plated steel sheet in the case where the plated texture 10S is hairline. If F3 is less than 1.10, the difference between the impression given by the plated texture 10S (hairline) in the state of no colored resin layer 11 and the impression of reflection of light at the surface of the colored resin layer 11 is excessively large. In this case, the metallic feeling is lost. In the case where the plating texture 10S is hairline, if F3 is 1.10 or more, it is possible to suppress a difference between an impression given by the plating texture 10S (hairline) in a state where the colored resin layer 11 is not present and an impression of reflection of light at the surface of the colored resin layer 11. Therefore, a sufficient metallic feeling can be obtained. The preferable lower limit of F3 is 1.15, more preferably 1.20, and still more preferably 1.25.

The surface roughness Ra (CL) is measured by a method for measuring an arithmetic average roughness specified in JIS B0601 (2013). Specifically, 10 arbitrary positions are set as measurement positions on the surface 11S of the colored resin layer 11. In each measurement position, the arithmetic average roughness Ra was measured for an evaluation length extending in the 1 st direction RD of the plating texture 10S. The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a stylus-type roughness meter, and the measurement speed was set to 0.5mm/sec. From the 10 calculated arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CL).

Similarly, the surface roughness Ra (CC) is measured by a method for measuring an arithmetic average roughness specified in JIS B0601 (2013). Specifically, 10 arbitrary positions are set as measurement positions on the surface 11S of the colored resin layer 11. At each measurement position, the arithmetic average roughness Ra was measured for an evaluation length extending in the 2 nd direction WD of the plating texture 10S. The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a stylus-type roughness meter, and the measurement speed was set to 0.5mm/sec. From the 10 calculated arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CC).

[ regarding the surface shape of the galvanized layer 10 (regarding the element (F)) when the plating texture 10S is hairline ]

The element (F) is the same as the element (E) and is an element when the plated texture 10S is hairline. The surface roughness Ra in the 2 nd direction WD of the surface of the galvanized layer 10 on which the plating texture 10S is formed is defined as Ra (MC). When the plating texture 10S is hairline, the surface roughness Ra (MC) may be 0.30 μm or more. When the surface roughness Ra (MC) is 0.30 μm or more, a sufficient metallic feeling can be obtained when the plated texture 10S is observed from above the colored resin layer 11. The lower limit of the surface roughness Ra (MC) is preferably 0.35. Mu.m, more preferably 0.40. Mu.m. The upper limit of the surface roughness Ra (MC) is not particularly limited. However, it is sometimes difficult to increase the surface roughness Ra (MC) excessively in industrial production. Therefore, the upper limit of the surface roughness Ra (MC) is, for example, 2.00. Mu.m. The upper limit of the surface roughness Ra (MC) may be, for example, 1.00 μm.

The surface roughness Ra (MC) was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). Specifically, the colored resin layer 11 of the plated steel sheet 1 is removed using a solvent that does not attack the galvanized layer 10, a remover (for example, trade name: neo reverse S-701 manufactured by trichromatic chemical Co., ltd.), or the like. In the plating texture 10S of the galvanized layer 10 after the colored resin layer 11 is removed, 10 arbitrary positions are taken as measurement positions. At each measurement position, the arithmetic average roughness Ra was measured with an evaluation length extending in the 2 nd direction WD. The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a stylus-type roughness meter, and the measurement speed was set to 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (MC).

[ concerning the exposure rate of the base Steel sheet ]

The exposure rate of the base steel sheet of the galvanized layer 10 of the plated steel sheet 1 is preferably less than 5%. In embodiment 1, corrosion resistance is sufficiently ensured by the galvanized layer 10 (galvanized or galvanized alloy). However, if the surface of the galvanized layer 10 is ground at the time of imparting the plating texture 10S, and as a result, the base steel sheet is exposed, there is a case where the long-term corrosion resistance (long-term corrosion resistance) is lowered due to the influence of galvanic corrosion. Such a decrease in long-term corrosion resistance is often remarkable when the exposure rate of the base steel sheet is 5% or more. Therefore, in embodiment 1, the exposure rate of the base steel sheet is preferably less than 5%.

If the exposure rate of the base steel sheet of the zinc coating layer 10 is less than 5%, excellent corrosion resistance can be obtained in addition to the moderate corrosion resistance required for general steels, which is excellent in long-term corrosion resistance. The upper limit of the exposure rate of the base steel sheet of the zinc coating layer 10 is preferably 3% or less, more preferably 2%, further preferably 1%, further preferably 0%.

The exposure rate of the base steel sheet was measured by the following method. Specifically, the colored resin layer 11 of the plated steel sheet 1 is removed using a solvent that does not attack the galvanized layer 10, a remover (for example, trade name: neo reverse S-7 01 manufactured by trichromatic chemical Co., ltd.), or the like. In the surface of the zinc coating layer 10, any 5 rectangular areas of 1mm×1mm are selected. EPMA analysis was performed on the selected rectangular area. By image analysis, a region (Zn undetected region) in which Zn was not detected in each rectangular region was specified. In embodiment 1, a region where the detected Zn intensity was 1/16 or less of the intensity of the measured standard sample (pure Zn) was regarded as a Zn undetected region. The ratio (area%) of the total area of Zn undetected regions among the 5 rectangular regions to the total area of 5 rectangular regions was defined as the base steel sheet exposure rate (area%).

[ concerning other coating ]

In the plated steel sheet 1 according to embodiment 1, an inorganic coating or an organic-inorganic composite coating may be formed between the colored resin layer 11 and the galvanized layer 10 for the purpose of improving corrosion resistance and adhesion. The inorganic coating film has light transmittance. The inorganic coating is, for example, an amorphous silica coating, a zirconia coating, or a phosphate coating. The organic-inorganic composite film has light transmittance. The organic-inorganic composite coating film contains, for example, a silane coupling agent and an organic resin. The organic-inorganic composite film has light transmittance.

[ morphology of texture ]

In fig. 4, hairline is shown as an example of texture. However, as described above, the morphology of the texture is not limited to hairline. The texture may have a plurality of convex portions and a plurality of concave portions. Therefore, the convex portion and the concave portion may or may not extend in one direction. The texture may be hairline, matt, or other forms. The texture may be a relief pattern.

[ method of production ]

An example of a method for producing the plated steel sheet 1 according to embodiment 1 will be described below. The manufacturing method described below is an example for manufacturing the plated steel sheet 1 of embodiment 1. Accordingly, the plated steel sheet 1 having the above-described configuration may be manufactured by a manufacturing method other than the manufacturing method described below. However, the manufacturing method described below is a preferable example of the manufacturing method of the plated steel sheet 1 of embodiment 1.

The manufacturing method of embodiment 1 includes: a preparation step (S1) of preparing a base steel sheet 100, a base material surface texture forming step (S2) of forming a base texture 100S on the surface of the base steel sheet 100, a galvanization treatment step (S3) of forming a galvanization layer 10 on the base steel sheet 100, a galvanization surface texture forming step (S4) as an optional step to be performed when the surface of the galvanization layer 10 is to be further textured, a polishing step (S5) of polishing the tip of the convex portion 10CO of the galvanization layer 10 as an optional step as needed, and a coloring resin layer forming step (S6) of forming a coloring resin layer 11 on the galvanization layer 10. Hereinafter, each step will be described.

[ preparation step (S1) ]

In the preparation step (S1), the base steel sheet 100 is prepared. The base steel sheet 100 may be a steel sheet or may have another shape. If the base steel sheet 100 is a steel sheet, the base steel sheet 100 may be a hot-rolled steel sheet or a cold-rolled steel sheet

[ step (S2) of Forming surface texture of base Material ]

The base material surface texture forming step (S2) is to form a base material texture 100S on the base material surface. In this case, the plated steel sheet has the structure shown in fig. 1. In the base material surface texture forming step (S2), a known texture process is applied to the surface of the base material steel sheet 100 to form a base material texture 100S on the surface of the base material steel sheet 100. If the base material texture 100S is hairline, a known hairline processing is performed. The hairline processing method includes: a method of forming hairlines by polishing a surface with a known polishing tape, a method of forming hairlines by polishing a surface with a known polishing brush, a method of forming hairlines by roll transfer with a roller having a hairline shape, and the like. The length, depth, and frequency of the hairline can be adjusted by adjusting the particle size of a known polishing belt, the particle size of a known grinding brush, or the surface shape of the roller.

[ Zinc plating treatment Process (S3) ]

In the galvanization process (S3), the prepared base steel sheet 100 is subjected to galvanization, and a galvanization layer 10 is formed on the surface of the base steel sheet 100.

The galvanization treatment may be performed by a known method. For example, the zinc plating layer 10 is formed by a known electroplating method. In this case, a known bath may be used for the zinc plating bath and the zinc alloy plating bath. Examples of the plating bath include sulfuric acid bath, chloride bath, zincate bath, cyanide bath, pyrophosphoric acid bath, boric acid bath, citric acid bath, other complex bath, and combinations thereof. The zinc alloy plating bath contains, for example, 1 or more kinds of single ions or complex ions selected from Co, cr, cu, fe, ni, P, sn, mn, mo, V, W, zr in addition to Zn ions.

The chemical composition, temperature, flow rate, and conditions (current density, current mode, etc.) of the zinc plating bath and the zinc alloy plating bath in the zinc plating process can be appropriately adjusted. The thickness of the zinc plating layer 10 in the zinc plating treatment can be adjusted by adjusting the current value and time within the range of the current density at the time of the zinc plating treatment.

The base material steel sheet 100 is formed with base material textures 100S. Therefore, if the base steel sheet 100 is subjected to the galvanization process to form the galvanized layer 10, a plating texture 10S along the base texture 100S is formed on the surface of the galvanized layer 10. By the above manufacturing steps, a plated steel sheet including the base steel sheet 100 having the base material grain 100S formed thereon and the zinc plating layer 10 having the plated grain 10S formed thereon can be manufactured.

[ concerning the galvanized surface texture formation step (S4) and the polishing step (S5) ]

The galvanized surface texture forming step (S4) and the polishing step (S5) are optional steps. That is, the galvanized surface texture forming step (S4) and the polishing step (S5) may not be performed. The galvanized surface texture forming step (S4) may be performed without performing the polishing step (S5). The polishing step (S5) may be performed without performing the galvanized surface texture forming step (S4). The zinc plating surface texture forming step (S4) and the polishing step (S5) may be both performed. In the case of performing the galvanized surface texture forming step (S4) and the polishing step (S5), either one of them may be performed first. The galvanized surface texture forming step (S4) and the polishing step (S5) are both steps of grinding the tips of the protrusions 10CO of the plated texture 10S of the galvanized layer 10. Hereinafter, each step will be described.

[ Zinc-plated surface texture Forming Process (S4) ]

The galvanized surface texture forming step (S4) is an optional step. That is, the galvanized surface texture forming step (S4) may or may not be performed. If this is done, in the galvanized surface texture forming step (S4), the tips of the projections 10CO in the plated texture 10S on the surface of the galvanized layer 10 shown in fig. 7 are ground to have a trapezoid shape as shown in fig. 8 so that the three-dimensional average roughness Sah of the tops of the projections is greater than 5nm and 200nm or less. Specifically, in the galvanized surface texture forming step (S4), the surface of the galvanized layer 10 (the plated texture 10S) of the plated steel sheet is subjected to a known texture processing, whereby the three-dimensional average roughness Sah of the tops of the projections of the plated texture 10S is set to be greater than 5nm and not more than 200 nm. At this time, the concave portions of the plating texture 10S are hardly ground. Therefore, the three-dimensional average roughness Sas of the recess bottom is maintained to be more than 200nm and not more than 2000 nm.

If the plating texture 10S is hairline, a known hairline processing is performed. As hairline processing methods, for example, there are: a method of polishing a surface with a known polishing tape to form hairlines, a method of polishing a surface with a known polishing brush to form hairlines, a method of performing roll transfer with a roller having a hairline shape to form hairlines, and the like. The degree of grinding of the tips of the protrusions 10CO of the plating texture 10S on the surface of the zinc plating layer 10 can be adjusted by adjusting the particle size of a known polishing belt, the particle size of a known polishing brush, or the surface shape of a roller. That is, by adjusting the particle size of the known polishing tape, the particle size of the known polishing brush, or the surface shape of the roller, the three-dimensional average roughness Sah at the top of the convex portion can be adjusted to be greater than 5nm and 200nm or less while maintaining the three-dimensional average roughness Sas at the bottom of the concave portion to be greater than 200nm and 2000nm or less. If hairline processing is performed in the galvanized surface texture forming step (S4), a new hairline of the plated texture 10S can be provided by adjusting the convex portion top three-dimensional average roughness Sah to be greater than 5nm and not more than 200nm while maintaining the concave portion bottom three-dimensional average roughness Sas to be greater than 200nm and not more than 2000 nm. The exposure rate of the base steel sheet may be adjusted by adjusting the particle size of a known polishing belt, the particle size of a known polishing brush, or the surface shape of a roll in the galvanized surface texture forming step (S4).

[ polishing step (S5) ]

The polishing step (S5) is an optional step. That is, the polishing step (S5) may not be performed. If this is done, in the polishing step (S5), the tips of the protrusions 10CO in the plated texture 10S on the surface of the galvanized layer 10 shown in fig. 7 are polished to have a trapezoid shape as shown in fig. 8 so that the three-dimensional average roughness Sah of the tops of the protrusions is greater than 5nm and 200nm or less. By this polishing treatment, the three-dimensional average roughness Sah of the top of the convex portion is set to be greater than 5nm and equal to or less than 200nm while the three-dimensional average roughness Sas of the bottom of the concave portion is maintained to be greater than 200nm and equal to or less than 2000 nm. As the polishing treatment, for example, there are: a method of polishing a surface with a known polishing tape, a method of polishing a surface with a known polishing brush, and the like. The shape of the protruding portion 10CO and the roughness of the surface of the protruding portion 10CO can be adjusted by adjusting the particle size of a known polishing tape or the particle size of a known polishing brush. That is, the three-dimensional average roughness Sah of the top of the convex portion can be adjusted by adjusting the particle size of a known polishing belt or the particle size of a known polishing brush. The grinding amount (grinding amount) in the grinding step (S5) is smaller than that in the galvanized surface texture forming step (S4). The exposure rate of the base steel sheet may be adjusted by adjusting the particle size of a known polishing belt or the particle size of a known polishing brush in the polishing step (S5).

The polishing step (S5) may be performed simultaneously with the galvanized surface texture forming step (S4). By doing so simultaneously, the production efficiency can be improved.

[ colored resin layer Forming Process (S6) ]

In the colored resin layer forming step (S6), the colored resin layer 11 is formed on the galvanized layer 10 of the plated steel sheet on which the plated grain 10S is formed. Hereinafter, the coloring resin layer forming step (S6) will be described in detail.

The paint used for forming the colored resin layer 11 is preferably a paint which, when applied to a plated steel sheet, immediately follows the surface shape of the steel material, and after reflecting the surface shape of the steel material, is slowly leveled. That is, a paint having a low viscosity if the shear rate is high and a high viscosity if the shear rate is low is preferable. Specifically, it is preferable that the viscosity be 10[ Pa.s ] or more at a shear rate of 0.1[1/sec ], and that the viscosity be 0.01[ Pa.s ] or less at a shear rate of 1000[1/sec ].

The shear viscosity of the coating can be adjusted by the following method. If the coating is an aqueous emulsion coating, a known viscosity modifier having hydrogen bonding property may be added to adjust the viscosity. Such hydrogen-bonding viscosity modifiers are constrained by hydrogen bonding at low shear rates. Thus, the viscosity of the paint can be increased. On the other hand, at high shear rates, hydrogen bonds are broken. Thus, the viscosity of the paint may be reduced.

The surface shape of the colored resin layer 11 can be adjusted by adjusting the shear viscosity of the paint used for forming the colored resin layer 11.

The method of forming the colored resin layer 11 on the galvanized layer 10 may be a known method. For example, a coating material whose viscosity is adjusted is applied to the galvanized layer 10 by a spray method, a roll coating method, a curtain coating method, or a dip coating method. Then, the paint on the galvanized layer 10 is naturally dried or baked to be dried, thereby forming a colored resin layer 11. The drying temperature, drying time, baking temperature, and baking time can be appropriately adjusted. The three-dimensional average roughness Saave, the minimum thickness DKmin, and the maximum thickness DKmax of the colored resin layer 11 can be adjusted by adjusting the shear viscosity of the paint used for forming the colored resin layer 11, the amount of coating on the galvanized layer 10, and the like. Further, by adjusting the content of the colorant in the paint, the colorant content CK in the colored resin layer 11 can be adjusted.

Through the above manufacturing steps, plated steel sheet 1 of embodiment 1 can be manufactured. The plated steel sheet 1 of embodiment 1 is not limited to the above-described production method, and the plated steel sheet 1 of embodiment 1 may be produced by a production method other than the above-described production method as long as the plated steel sheet 1 having the above-described constitution can be produced. However, the above-described production method is suitably used for producing the plated steel sheet 1 of embodiment 1.

(embodiment 2)

In the plated steel sheet according to embodiment 1, improvement of both adhesion to the colored resin layer and visibility of texture on the surface of the galvanized layer has been attempted. However, depending on the application of the plated steel sheet, texture visibility may be higher than adhesion of the colored resin layer. Accordingly, the present inventors studied a plated steel sheet having a colored appearance and a galvanized layer with a higher visibility of the surface texture. As described in patent documents 1 and 2, a galvanized steel sheet in which a transparent resin layer is formed on a galvanized layer has been proposed. Accordingly, the present inventors have first tried to produce a galvanized steel sheet in which a resin layer formed on a galvanized layer is colored by containing a colorant.

The result shows that: in the case where the colorant is contained in the resin layer, depending on the conditions, there are cases where the texture formed on the surface of the galvanized layer cannot be confirmed by naked eyes. Therefore, the present inventors have studied and studied factors that affect visual confirmation of texture when a colorant is contained in a resin. As a result, the present inventors have obtained the following findings.

If a colored resin layer containing a colorant is formed on a galvanized layer having a texture formed on the surface, the content of the colorant in the colored resin layer and the thickness of the colored resin layer may affect visual confirmation of the texture. Specifically, if the content of the colorant in the colored resin layer is too large, the texture becomes unable to be confirmed by the naked eye. Further, if the colored resin layer is too thick, the texture becomes unable to be confirmed by the naked eye.

In addition, the shape of the texture may also have an impact on visual confirmation of the texture. When a texture is formed on the surface of the zinc plating layer, not only the texture irregularities but also minute irregularities due to zinc plating crystallization are present on the textured surface. If the fine irregularities caused by the zinc plating crystals are large, light is diffusely reflected due to the fine irregularities caused by the zinc plating crystals. In this case, the gloss of the texture may be reduced, and the texture may whiten. Therefore, if a colored resin layer is formed on the galvanized layer, the texture becomes difficult to be confirmed by the naked eye. Therefore, from the viewpoint of further improving visibility of the texture, it is preferable to suppress roughness (minute irregularities) of microscopic regions at the tip (convex portion) or the bottom (concave portion) of the texture extending in one direction.

In addition, in a cross section perpendicular to the extending direction of the texture, the thickness of the resin formed on the texture varies according to the irregularities of the texture. Fig. 9 is a schematic view of a cross section perpendicular to the extending direction of the grain in the plated steel sheet of the present embodiment. Referring to fig. 9, the plated steel sheet includes a zinc plating layer 10', a colored resin layer 11'. The surface of the zinc plating layer 10 'is formed with a texture 10S'. The texture 10S ' includes a Convex portion 10CO ' (Convex) and a concave portion 10RE ' (recovery).

The colored resin layer 11 'is formed on the surface of the galvanized layer 10'. Therefore, the surface 11S 'of the colored resin layer 11' reflects the irregularities of the texture 10S 'to some extent, but is flatter than the texture 10S'. Specifically, in the surface 11S ' of the colored resin layer 11', the convex portions 11CO ' are formed at the portions corresponding to the convex portions 10CO ' of the texture 10S '. The height of the convex portion 11CO 'is lower than the height of the convex portion 10 CO'. That is, the surface 11S ' of the colored resin layer 11' is more planarized than the surface of the texture 10S '.

Here, in a range where the length in the direction perpendicular to the extending direction of the texture 10S ' is 100 μm, the maximum thickness (μm) of the colored resin layer 11' is defined as DKmax '. Further, the minimum thickness (μm) of the colored resin layer 11 'is defined as DKmin'. In order to make the texture 10S 'visually identifiable even when the texture is colored by the colored resin layer 11', the content of the colorant in the colored resin layer 11 'and the thickness of the colored resin layer 11' are limited to a certain extent as described above. Under this limitation, the difference between the maximum thickness DKmax ' and the minimum thickness DKmin ' of the colored resin layer 11' is reflected in the brightness difference. Specifically, by making the difference between the maximum thickness DKmax 'and the minimum thickness DKmin' of the colored resin layer 11 'large to a certain extent, the concave portion 10RE' and the convex portion 10CO 'of the texture 10S' are different in brightness. As a result, even in the case where the colored resin layer 11 'is formed, the texture 10S' can be visually confirmed.

Based on the above findings, the present inventors have found that a plated steel sheet having a colored appearance and a surface texture of a galvanized layer that can be visually confirmed can be produced by the following (a ') to (C'): the difference between the maximum thickness DKmax 'and the minimum thickness DKmin' of the colored resin layer 11 'in the cross section perpendicular to the extending direction of the texture 10S' is set to a certain level (a ') by adjusting the roughness of the micro areas of the convex portion 10CO' and the concave portion 10RE 'of the texture 10S' (B ') by adjusting the thickness and the colorant content of the colored resin layer 11'.

The plated steel sheet of embodiment 2 completed based on the above findings has the following constitution.

[11] The plated steel sheet of (1) comprises:

a base steel plate,

A zinc-plated layer formed on the surface of the base steel sheet, and

a colored resin layer formed on the zinc plating layer,

the zinc coating layer has a texture extending in one direction on its surface,

the colored resin layer contains a colorant,

the plated steel sheet satisfies all of the following conditions (A ') to (C'):

and (A ') measuring a roughness profile having a length in a range of 1000 [ mu ] m in a direction perpendicular to the extending direction of the texture, wherein 10 positions designated in order from a low height among the positions on the roughness profile obtained by the measurement are defined as concave bottom points, 10 positions designated in order from a high height among the positions on the roughness profile obtained by the measurement are defined as convex top points, and a three-dimensional average roughness Sa' of a micro region of 1 [ mu ] m x 1 [ mu ] m centered on each concave bottom point and each convex top point is measured, and an arithmetic average of the three-dimensional average roughness Saave 'obtained by the measurement is defined as three-dimensional average roughness Saave' having a three-dimensional average roughness of more than 5nm and not more than 200 nm.

DKmin’×CK’≤15.0 (1’)；

(DKmax’-DKmin’)×CK’>1.0 (2’)。

[12] the steel sheet plated according to [11], wherein,

the texture may be a hairline,

the plated steel sheet may satisfy the following (D ') and (E'):

Ra(CC)’≥Ra(CL)’×1.10 (3’)；

[13] The plated steel sheet of [11] or [12], wherein,

Hereinafter, the plated steel sheet of embodiment 2 will be described in detail.

[ concerning plated Steel sheet 1' ]

Fig. 10 is a cross-sectional view of a plated steel sheet 1' according to embodiment 2. In fig. 10, a direction perpendicular to the paper surface is defined as an extending direction RD ' of the grain 10S ' (i.e., a rolling direction of the plated steel sheet 1 '). The thickness direction of the plated steel sheet 1 'is defined as the thickness direction TD'. In the plated steel sheet 1', a direction perpendicular to the extending direction RD' and the thickness direction TD 'of the texture is defined as a width direction WD'. Here, RD ', TD ' and WD ' in this definition are substantially the same concept as RD, TD and WD in embodiment 1.

Referring to fig. 10, a plated steel sheet 1' according to embodiment 2 includes: base steel sheet 100', zinc plating layer 10', colored resin layer 11'. The zinc plating layer 10 'is formed on the surface of the base steel sheet 100'. The colored resin layer 11' is formed on the surface (texture) 10S ' of the galvanized layer 10 '. The zinc coat layer 10' is disposed between the base steel sheet 100' and the colored resin layer 11'. Hereinafter, the base steel sheet 100', the galvanized layer 10', and the colored resin layer 11' will be described.

[ concerning the base material steel sheet 100 ]

The base steel sheet 100' may be a known steel sheet suitable for use as a plated steel sheet (e.g., zinc plated steel sheet, zinc alloy plated steel sheet, hot dip galvanized steel sheet, alloyed hot dip galvanized steel sheet, etc.) depending on the mechanical properties (e.g., tensile strength, workability, etc.) required for the plated steel sheet to be produced. For example, as the base steel sheet 100', a steel sheet for electric appliance use or a steel sheet for vehicle outer panel use may be used. The base steel sheet 100' may be a hot-rolled steel sheet or a cold-rolled steel sheet.

[ concerning the Zinc-plated layer 10 ]

The zinc plating layer 10 'is formed on the surface of the base steel sheet 100'. In embodiment 2, the zinc plating layer 10' is disposed between the base steel sheet 100' and the colored resin layer 11 '. The zinc plating layer 10' may be formed by a well-known zinc plating treatment method. Specifically, the zinc plating layer 10' can be formed by any one of plating methods such as an electroplating method and a molten plating method. In this specification, the zinc plating layer 10' also includes a zinc alloy plating layer. More specifically, the galvanized layer 10' is a concept including a zinc plating layer, a zinc alloy plating layer, a hot dip galvanized layer, and an alloyed hot dip galvanized layer.

The zinc plating layer 10' in embodiment 2 may have a known chemical composition. For example, the Zn content in the chemical composition of the galvanized layer 10' may be 65% or more by mass%. If the Zn content is 65% by mass or more, the sacrificial corrosion prevention function can be significantly exhibited, and the corrosion resistance of the plated steel sheet 1' is significantly improved. The lower limit of the Zn content in the chemical composition of the zinc-plated layer 10' is preferably 70%, more preferably 80%.

The chemical composition of the zinc plating layer 10' preferably contains 1 element or 2 elements or more selected from Al, co, cr, cu, fe, ni, P, si, sn, mg, mn, mo, V, W, zr in addition to Zn. When the zinc plating layer 10 'is a zinc plating layer, the chemical composition of the zinc plating layer 10' preferably contains at least 1 element selected from Fe, ni, and Co in a total amount of 5 to 20 mass%, and the remainder is composed of Zn and impurities. When the zinc plating layer 10 'is a hot dip zinc plating layer, the chemical composition of the zinc plating layer 10' preferably contains at least 1 element selected from Mg, al, and Si in a total amount of 5 to 20 mass%, and the remainder is composed of Zn and impurities. In these cases, the galvanized layer 10' further exhibits excellent corrosion resistance.

The zinc coating layer 10' may also contain impurities. Here, the impurities refer to impurities mixed in raw materials or mixed in a manufacturing process. The impurity is Ti, B, S, N, C, nb, pb, cd, ca, pb, Y, la, ce, sr, sb, O, F, cl, zr, ag, W, H, for example. In the chemical composition of the galvanized layer 10', the total content of impurities is preferably 1% or less.

The chemical composition of the galvanized layer 10' can be measured, for example, by the following method. The colored resin layer 11' of the plated steel sheet 1' is removed with a stripping agent such as a solvent that does not attack the galvanized layer 10', a stripping agent (for example, trade name: neo reverse S-7 01 manufactured by Sanyoku chemical Co., ltd.). Then, the zinc plating layer 10' is dissolved using hydrochloric acid to which an inhibitor is added. The solution was subjected to ICP analysis using an ICP (Inductively Coupled Plasma: inductively coupled plasma) emission spectrometry device to determine the Zn content. If the obtained Zn content is 65% or more, the plating layer to be measured is determined to be the zinc plating layer 10'.

[ concerning the amount of adhesion of the galvanized layer 10 ]

The amount of the zinc plating layer 10' to be adhered is not particularly limited, and a known amount may be sufficient. The preferable adhesion amount of the zinc plating layer 10' is 5.0 to 120.0g/m ² . If the adhesion amount of the zinc coating layer 10' is 5.0g/m ² As described above, when the texture described later is applied to the galvanized layer 10', exposure of the base steel sheet (base steel sheet 100') can be suppressed. A further preferable lower limit of the adhesion amount of the zinc plating layer 10' is 7.0g/m ² Further preferably 10.0g/m ² . The upper limit of the adhering amount of the zinc plating layer 10' is not particularly limited. From the viewpoint of economy, in the case of the galvanized layer 10' formed by the electroplating method, the upper limit of the adhesion amount is preferably 40.0gm ² Further preferably, the upper limit is 35.0g/m ² Further preferably 30.0g/m ² 。

[ concerning the colored resin layer 11 ]

The colored resin layer 11' is formed on the surface (texture) 10S ' of the galvanized layer 10 '. Fig. 11 is an enlarged view of the colored resin layer 11' shown in fig. 10. Referring to fig. 11, the colored resin layer 11' includes a resin 31' and a colorant 32'. The colorant 32 'is contained in the resin 31'. Hereinafter, the resin 31 'and the colorant 32' will be described.

[ concerning resin 31' ]

The resin 31' is a resin having light transmittance. In embodiment 2, the term "resin having light transmittance" means that when the plated steel sheet 1 'including the colored resin layer 11' containing the colorant 32 'and the resin 31' is placed in an environment corresponding to sunlight in the morning of a sunny day (illuminance of about 65000 lux), the texture 10S 'of the galvanized layer 10' can be visually confirmed. The resin 31 'functions as an adhesive for fixing the colorant 32'.

The resin 31' is not particularly limited as long as it has light transmittance as defined above, and a known natural resin or a known synthetic resin can be used. The resin 31' in embodiment 2 may be, for example, 1 or 2 or more selected from epoxy resin, urethane resin, polyester resin, phenol resin, polyether sulfone resin, melamine alkyd resin, acrylic resin, polyamide resin, polyimide resin, polysiloxane resin, polyvinyl acetate resin, polyolefin resin, polystyrene resin, vinyl chloride resin, and vinyl acetate resin.

[ concerning colorant 32 ]

The colorant 32' is contained in the resin 31' to color the colored resin layer 11 '. The colorant 32' in embodiment 2 is a known colorant and widely includes colorants used for coloring a resin layer formed on the surface of a steel sheet, such as an inorganic pigment, an organic pigment, and a dye. Colorant 32' is a colored colorant. Chromatic colors are colors having hue, lightness, and chroma properties. The colorant 32' contains, for example, 1 or more selected from inorganic pigments, organic pigments, and dyes. The colorant 32' is more preferably a pigment (inorganic pigment and/or organic pigment) from the viewpoint of durability against ultraviolet rays.

In the case where the colorant 32 'is an inorganic pigment, the colorant 32' is, for example, a neutral precipitated pigment (sulfate, carbonate, etc.) and/or a fired pigment (metal sulfide, metal oxide, polyvalent metal composite oxide, etc.). In the case where the colorant 32 'is an organic pigment, the colorant 32' is, for example, 1 or more selected from chlorine pigments, azo pigments (dissolved azo lake pigments, insoluble azo pigments, etc.), acid-condensed pigments, polycyclic pigments (phthalocyanine pigments, indigo pigments, quinacridone pigments, anthraquinone pigments, etc.), metal complex pigments (azo chelate pigments, transition metal complex pigments, etc.). In the case where the colorant 32 'is a dye, the colorant 32' is, for example, 1 or more selected from azo dyes, indigo dyes, anthraquinone dyes, sulfur dyes, carbonium dyes.

The color of the colorant 32' is not particularly limited. The colorant 32 'is, for example, carbon black (C'), iron black (Fe) ₃ O ₄ ) Is black in color. However, the colorant 32 'is not limited to black, and may be other colored colorants 32' (white, purplish red, yellow, green blue, red, orange, yellow, green, cyan, blue, violet, etc.).

In the case where the colorant 32' is a pigment, the particle diameter is not particularly limited. When the colorant 32' is a pigment, the maximum value of the primary particle diameter is, for example, 3nm to 1000nm.

[ concerning the texture 10S' formed on the surface of the galvanized layer 10 ]

A grain 10S ' is formed on the surface of the galvanized layer 10' of the plated steel sheet 1 '. That is, the galvanized layer 10' of the plated steel sheet 1' has a texture 10S ' on its surface. The texture 10S' extends in one direction. In embodiment 2, "texture" means a concave-convex pattern formed on the surface of the zinc plating layer 10' by physical or chemical means. The preferred texture is hairline. The hairline is a linear concave-convex pattern extending in one direction.

[ case where texture 10S' is hairline ]

Fig. 12 is a top view of the galvanized layer 10 'with hairlines formed on the surface as the texture 10S'. Referring to fig. 12, hairline 10S 'is a straight concave-convex pattern formed on the surface of galvanized layer 10'. The extending direction RD 'of the hairline 10S' is the same direction. The same direction here means that 90% or more of the hairlines adjacent to each other form an angle of less than ±5° in the direction WD ' aligned in the direction perpendicular to the extending direction RD ' of the hairline 10S ' when the galvanized layer 10' is viewed from the thickness direction TD ' (i.e., in the plan view as shown in fig. 12).

[ concerning the requirements (A ')to (C') ]

The plated steel sheet 1' of embodiment 2 having the above-described configuration further satisfies all of the following conditions (a ') to (C ').

Requirement (a'):

a roughness profile having a length in a range of 1000 μm in a direction WD ' perpendicular to an extending direction RD ' of the texture 10S ' was measured, 10 positions designated in order from a low height were defined as concave bottom points among positions on the roughness profile obtained by the measurement, and 10 positions designated in order from a high height were defined as convex top points among positions on the roughness profile obtained by the measurement. The three-dimensional average roughness Sa' of a 1 μm×1 μm minute region centered on the bottom of each concave portion and the top of each convex portion was measured. The arithmetic average value of the measured three-dimensional average roughness Sa 'is defined as the three-dimensional average roughness Saave'. At this time, the three-dimensional average roughness Saave' is more than 5nm and not more than 200 nm.

Requirement (B'):

in the range of the length of 100 μm in the direction WD ' perpendicular to the extending direction RD ' of the texture 10S ', the minimum thickness (μm) of the colored resin layer 11' is defined as DKmin '. Further, the content (area%) of the colorant 32' in the colored resin layer 11' is defined as CK '. At this time, the minimum thickness DKmin ' of the colored resin layer 11' and the content CK ' of the colorant 32' satisfy the formula (1 ').

DKmin’×CK’≤15.0 (1’)

Requirement (C'):

in the range of the length of 100 μm in the direction WD ' perpendicular to the extending direction RD ' of the texture 10S ', the maximum thickness (μm) of the colored resin layer 11' is defined as DKmax '. At this time, the maximum thickness DKmax ' of the colored resin layer 11', the minimum thickness DKmin ' of the colored resin layer 11', and the content CK ' of the colorant 32' satisfy the formula (2 ').

(DKmax’-DKmin’)×CK’>1.0 (2’)

The following describes each element in detail.

[ concerning the requirement (A') ]

Fig. 13 is a view showing a roughness profile of the texture 10S 'formed on the surface of the galvanized layer 10'. Referring to fig. 13, an arbitrary length range of 1000 μm is selected in a direction WD ' perpendicular to the extending direction RD ' of the texture 10S '. The roughness profile of the texture 10S' was measured over a selected length of 1000 μm. The resulting roughness profile is assumed to be the shape as in fig. 13.

Among the positions on the roughness profile obtained by measurement, 10 positions of low height are sequentially designated in order of low height from the position of lowest height. The designated positions are defined as recess bottom points PRE1', PRE2', …, PRE10' in order from the beginning of the low height. Among the positions on the roughness profile obtained by measurement, 10 high positions are designated in order of height from the highest position. The designated positions are defined as convex portion apexes PCO1', PCO2', …, PCO10' in order from the high.

As shown in fig. 14A, in a plan view of the surface of the zinc plating layer 10', a 1 μm×1 μm minute recessed area 200' centered on each recessed bottom point PREk ' (k is 1 to 10) defined is designated. In fig. 14A, the longitudinal direction of the micro concave area 200' is parallel to the extending direction RD ' of the texture 10S ', and the lateral direction of the micro concave area 200' is parallel to the width direction WD '. However, if the micro concave area 200 'is a surface including the extending direction RD' and the width direction WD ', each side of the micro concave area 200' may not be parallel to the extending direction RD 'or the width direction WD'.

Similarly, as shown in fig. 14B, in a plan view of the surface of the galvanized layer 10', a 1 μm×1 μm minute convex region 300' centered on each of the defined convex portion vertices PCOk ' (k is 1 to 10) is designated. In fig. 14B, the longitudinal direction of the minute convex section 300' is parallel to the extending direction RD ' of the texture 10S ', and the lateral direction of the minute convex section 300' is parallel to the width direction WD '. However, if the minute convex section 300 'is a surface including the extending direction RD' and the width direction WD ', each side of the minute convex section 300' may not be parallel to the extending direction RD 'or the width direction WD'.

The three-dimensional average roughness Sa ' was measured in 10 fine concave regions 200' and 10 fine convex regions 300' designated by the above method. The three-dimensional average roughness Sa' is an arithmetic average height specified in ISO 25178 by expanding Ra (arithmetic average height of line) specified in JIS B0601 (2013) to a plane. The arithmetic average of the measured 20 three-dimensional average roughness Sa 'was defined as the three-dimensional average roughness Saave'. At this time, the arithmetic average roughness Saave' is more than 5nm and 200nm or less.

Nano-scale micro irregularities (hereinafter referred to as micro irregularities) caused by zinc plating crystals exist in the vicinity of the protruding apex or the recessed base of the texture 10S'. If the minute irregularities have a certain size, light is diffusely reflected by the minute irregularities. In this case, the gloss of the texture is reduced and the texture is whitened. Therefore, if a colored resin layer is formed on the galvanized layer, the texture becomes difficult to be confirmed by the naked eye. Therefore, from the viewpoint of further improving visibility of the texture, the minute irregularities in the minute regions 200 'and 300' are preferably as small as possible.

In embodiment 2, the three-dimensional average roughness Saave' based on the definition is greater than 5nm and 200nm or less. If the three-dimensional average roughness Saave' is 200nm or less, diffuse reflection of light in the vicinity of the convex portion peak and the concave portion bottom point can be further suppressed. In this case, in the plated steel sheet 1' of embodiment 2 having the colored resin layer 11', the texture 10S ' becomes more easily confirmed by the naked eye. The smaller the three-dimensional average roughness Saave', the more preferable. However, it is extremely difficult to set the three-dimensional average roughness Saave' to 5nm or less. Therefore, in embodiment 2, the three-dimensional average roughness Saave' is more than 5nm and 200nm or less. The upper limit of the three-dimensional average roughness Saave' is preferably 190nm, more preferably 180nm, and still more preferably 170nm.

[ concerning the requirement (B') ]

Referring to fig. 9, attention is paid to a cross section of an arbitrary length in a range of 100 μm in a direction WD ' perpendicular to an extending direction RD ' of the texture 10S '. The cross section (fig. 9) of the range of 100 μm in length was defined as the observation cross section. In the observation section, the minimum thickness among the thicknesses of the colored resin layers 11 'is defined as DKmi n' (μ). In the observation section, the maximum thickness among the thicknesses of the colored resin layers 11 'is defined as DKmax' (μm).

Further, in the observation section, the content (area%) of the colorant in the colored resin layer 11 'is defined as CK'. As described above, in the present specification, the colorant content CK' is expressed as an area ratio (area%) of the colorant in the observation section.

As described above, when the minimum thickness DKmin ' (μm), the maximum thickness DKmax ' (μm), and the colorant content CK ' (area%) of the colored resin layer 11' are defined, the minimum thickness DKmin ' of the colored resin layer 11' and the content CK ' of the colorant 32' satisfy the formula (1 ').

DKmin’×CK’≤15.0(1’)

If the formula (1 ') is not satisfied, that is, if the product of the minimum thickness DKmin ' and the colorant content CK ' is greater than 15.0, the thickness of the colored resin layer 11' is too thick or the colorant content CK ' is too large. In this case, the coloring of the colored resin layer 11' is too intense, and the texture 10S ' of the galvanized layer 10' is difficult to be visually confirmed. If the product of the minimum thickness DKmin ' and the colorant content CK ' is 15.0 or less, the texture 10S ' on the surface of the galvanized layer 10' can be sufficiently visually confirmed while having the appearance colored by the colored resin layer 11' provided that the condition (a ') and the condition (C ') are satisfied. The upper limit of DKmin '×ck' is preferably 14.0, more preferably 13.0, and still more preferably 12.0. The lower limit of Dkmin '. Times.CK' is not particularly limited. The lower limit of Dkmin '. Times.CK' is, for example, 4.0.

The thickness of the colored resin layer 11' in embodiment 2 was measured by the following method. A sample having a cross section perpendicular to the extending direction RD 'of the texture 10S' on the surface is collected. An observation section of the sample was observed with a Scanning Electron Microscope (SEM) in a range of 100 μm in length in a direction WD ' perpendicular to the extending direction RD ' of the texture 10S ' in a 2000-fold reflected electron image (BSE). In observation of a reflected electron image (BSE) using a Scanning Electron Microscope (SEM), the base steel sheet 100', the galvanized layer 10', and the colored resin layer 11' can be easily distinguished by contrast. In the observation section, the thickness of the colored resin layer 11 'was measured at a pitch of 0.5 μm in the direction WD'. The minimum thickness among the measured thicknesses is defined as the minimum thickness Dkmin' (μm). The maximum thickness among the measured thicknesses is defined as the maximum thickness DKmax' (μm). If it is necessary to determine whether the resin layer 11 'is colored (i.e., whether the resin contains a colorant), it is determined whether the resin layer 11' is colored by TEM observation described later.

The colorant content CK '(area%) in the colored resin layer 11' was determined by the following method. A sample having a cross section perpendicular to the extending direction RD 'of the texture 10S' at the surface is collected. A section perpendicular to the extending direction RD 'of the texture 10S' in the sample is defined as a viewing surface. A thin film sample capable of observing the colored resin layer 11 'and the galvanized layer 10' of the observation surface was prepared from the sample using a Focused Ion Beam apparatus (FIB: focused Ion Beam). The thickness of the film sample was set to 50 to 200nm. In the observation surface of the prepared film sample, a field of view having a length of 3 μm in a direction perpendicular to the thickness direction of the colored resin layer 11' (i.e., direction WD ') and a length including the entire colored resin layer 11' in the thickness direction of the colored resin layer 11' (i.e., direction TD ') was observed using a transmission electron microscope (TEM: transmission Electron Microsc ope). In the TEM observation, the resin 31' and the colorant 32' in the colored resin layer 11' can be identified by contrast. Determining a plurality of colors in the colored resin layer 11' in the field of view Total area A1' (μm) of agent 32 ² ). Then, the area A0 '(μm) of the colored resin layer 11' in the visual field was obtained ² ). The colorant content (area%) in the colored resin layer 11' was determined by the following formula based on the obtained total area A1' and area A0 '.

CK＝A1’/A0’×100

[ concerning the requirement (C') ]

In an observation cross section having a length in a range of 100 μm in a direction WD 'perpendicular to the extending direction RD' of the texture 10S ', wherein the observation cross section is a cross section perpendicular to the extending direction RD' of the texture 10S ', a maximum thickness DKmax of the colored resin layer 11', a minimum thickness DKmin of the colored resin layer 11', and a content CK' of the colorant 32 'satisfy the formula (2').

(DKmax’-DKmin’)×CK’>1.0 (2’)

(DKmax '-Dkmin'). Times.CK 'is an index of contrast of brightness in the colored resin layer 11'. If (DKmax '-Dkmin'). Times.CK 'is 1.0 or less, the contrast of brightness in the colored resin layer 11' is low. In this case, the contrast of the brightness of the colored resin layer 11 'cannot be sufficiently utilized for visual confirmation of the texture 10S'. Therefore, the texture 10S 'under the colored resin layer 11' is difficult to be visually confirmed.

If (DKmax '-Dkmin'). Times.CK 'is higher than 1.0, the contrast of brightness in the colored resin layer 11' is sufficiently high. In this case, the contrast of the brightness of the colored resin layer 11 'can be sufficiently utilized for visual confirmation of the texture 10S'. As a result, the texture 10S 'under the colored resin layer 11' can be sufficiently visually confirmed on the premise that the requirement (a ') and the requirement (B') are satisfied.

The preferable lower limit of (DKmax ' -Dkmin '). Times.CK ' is 1.2, more preferably 1.5, still more preferably 1.8, still more preferably 2.0. The upper limit of (Dkmax ' -Dkmin '). Times.CK ' is not particularly limited. The upper limit of (DKmax ' -Dkmin '). Times.CK ' is, for example, 15.0.

[ concerning the thickness of the colored resin layer 11 ]

In the plated steel sheet 1 'of embodiment 2, the average thickness of the colored resin layer 11' is preferably 10.0 μm or less. If the thickness of the colored resin layer 11 'exceeds 10.0 μm, it is easy to smooth (leveling) only the colored resin layer 11', and the difference between the impression of reflection at the surface of the colored resin layer 11 'and the impression of the texture 10S' that can be confirmed with the naked eye becomes large. In this case, the metallic feeling of the plated steel sheet 1' is reduced. If the average thickness of the colored resin layer 11' is 10.0 μm or less, the texture 10S ' of the galvanized layer 10' can be visually confirmed and the metallic feel can be sufficiently improved on the premise that all of the above-mentioned requirements (a ') to (C ') are satisfied. The upper limit of the average thickness of the colored resin layer 11' is more preferably 9.0 μm, and still more preferably 8.0 μm.

Further, the preferable lower limit of the average thickness of the colored resin layer 11' is 0.5 μm. If the average thickness of the colored resin layer 11' is 0.5 μm or more, the corrosion resistance is further improved. The lower limit of the average thickness of the colored resin layer 11' is more preferably 0.7. Mu.m, still more preferably 1.0. Mu.m, still more preferably 2.0. Mu.m, still more preferably 3.0. Mu.m.

The average thickness of the colored resin layer 11' was measured by the following method. In the above-mentioned observation section, the arithmetic average value of the thicknesses measured at a pitch of 0.5 μm in the direction WD 'is defined as the average thickness (μm) of the colored resin layer 11'.

[ other morphology of colored resin layer 11 ]

The colored resin layer 11' of the plated steel sheet 1' of embodiment 2 may contain additives for further imparting corrosion resistance, slidability, conductivity, and the like to the colored resin layer 11 '. Examples of the additives for imparting corrosion resistance include well-known rust inhibitors and inhibitors. Additives for imparting slidability are, for example, well-known waxes and beads. The additive for imparting conductivity is, for example, a known conductive agent.

[ concerning the surface shape of the preferable colored resin layer 11 '(concerning the condition (D')) ]

The colored resin layer 11' preferably has a surface shape as described in detail below due to the kind of the texture 10S ' formed on the surface of the galvanized layer 10' as the lower layer.

The surface roughness Ra of the colored resin layer 11 'in the extending direction RD' of the texture 10S 'is defined as Ra (CL)'. When the texture 10S 'is hairline, the surface roughness Ra of the colored resin layer 11' in the direction WD 'perpendicular to the extending direction RD' of the texture 10S 'is defined as Ra (CC)'. At this time, it is preferable that the surface roughness Ra (CC) ' and the surface roughness Ra (CL) ' satisfy the formula (3 ').

Ra(CC)’≥Ra(CL)’×1.10(3’)

If the surface roughness Ra (CC) 'of the colored resin layer 11' is smaller than 1.10 times with respect to the surface roughness Ra (CL) 'the difference between the impression given by the texture 10S' in the state of the non-colored resin layer 11 'and the impression of reflection of light at the surface of the colored resin layer 11' becomes excessively large. In this case, the metallic feeling is lost. If the surface roughness Ra (CC) ' is 1.10 times or more with respect to the surface roughness Ra (CL) ' it is possible to suppress a difference between the impression given by the texture 10S ' in the state of the non-colored resin layer 11' and the impression of reflection of light at the surface of the colored resin layer 11 '. Therefore, a sufficient metallic feeling can be obtained. The surface roughness Ra (CC) ' of the colored resin layer 11' is more preferably 1.15 times or more, still more preferably 1.20 times or more, and still more preferably 1.25 times or more the surface roughness Ra (CL) '.

The surface roughness Ra (CL)' was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). Specifically, any 10 positions are defined as measurement positions on the surface 11S 'of the colored resin layer 11'. At each measurement position, the arithmetic average roughness Ra was measured for an evaluation length extending in the extending direction RD 'of the texture 10S'. The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a stylus-type roughness meter, and the measurement speed was set to 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CL)'.

Similarly, the surface roughness Ra (CC)' was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). Specifically, on the surface 11S 'of the colored resin layer 11', 10 arbitrary positions were set as measurement positions. At each measurement position, the arithmetic average roughness Ra is measured with an evaluation length extending in the direction WD ' perpendicular to the extending direction RD ' of the texture 10S '. The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a stylus-type roughness meter, and the measurement speed was set to 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CC)'.

[ concerning the surface shape of the galvanized layer 10 '(concerning the element (E')) ]

The surface roughness Ra of the surface of the galvanized layer 10' on which the texture 10S ' is formed in the direction WD ' perpendicular to the extending direction of the texture 10S ' is defined as Ra (MC) '. When the texture 10S 'is hairline, the surface roughness Ra (MC)' is preferably 0.30 μm or more. If the surface roughness Ra (MC) ' is less than 0.30 μm, it is difficult to confirm the texture 10S ' with the naked eye from above the colored resin layer 11 '. If the surface roughness Ra (MC) ' is 0.30 μm or more, the texture 10S ' can be sufficiently confirmed with the naked eye from above the colored resin layer 11 '. The lower limit of the surface roughness Ra (MC)' is more preferably 0.35. Mu.m, and still more preferably 0.40. Mu.m. The upper limit of the surface roughness Ra (MC)' is not particularly limited. However, it is sometimes difficult to industrially increase the surface roughness Ra (MC)' excessively. Therefore, the upper limit of the surface roughness Ra (MC)' is, for example, 2.00. Mu.m. The upper limit of the surface roughness Ra (MC)' may be, for example, 1.00 μm.

The surface roughness Ra (MC)' was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). Specifically, the colored resin layer 11' of the plated steel sheet 1' is removed with a stripping agent such as a solvent that does not attack the galvanized layer 10', a stripping agent (for example, trade name: neo reverse S-701 manufactured by Sanyoku chemical Co., ltd.). In the texture 10S ' of the galvanized layer 10' after the colored resin layer 11' is removed, an arbitrary 10 positions are taken as measurement positions. At each measurement position, the arithmetic average roughness Ra is measured with an evaluation length extending in the direction WD ' perpendicular to the extending direction RD ' of the texture 10S '. The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a stylus-type roughness meter, and the measurement speed was set to 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (MC)'.

[ concerning the exposure rate of the base Steel sheet ]

The base steel sheet of the galvanized layer 10 'of the plated steel sheet 1' preferably has an exposure rate of less than 5%. In embodiment 2, corrosion resistance is sufficiently ensured by the galvanized layer 10' (galvanization or galvanization alloy). However, if the surface of the galvanized layer 10 'is ground at the time of imparting the texture 10S', and as a result, the base steel sheet is exposed, there is a case where the long-term corrosion resistance (long-term corrosion resistance) is lowered due to the influence of galvanic corrosion. Such a decrease in long-term corrosion resistance is often remarkable when the exposure rate of the base steel sheet is 5% or more. Therefore, in embodiment 2, the exposure rate of the base steel sheet is preferably less than 5%.

If the exposure rate of the base steel sheet of the galvanized layer 10' is less than 5%, excellent corrosion resistance can be obtained in addition to the moderate corrosion resistance required for general steels, which is excellent in long-term corrosion resistance. The upper limit of the exposure rate of the base steel sheet of the zinc coating layer 10' is preferably 3% or less, more preferably 2%, still more preferably 1%, still more preferably 0%.

The exposure rate of the base steel sheet was measured by the following method. Specifically, the colored resin layer 11' of the plated steel sheet 1' is removed with a stripping agent such as a solvent that does not attack the galvanized layer 10', a stripping agent (for example, trade name: neo reverse S-701 manufactured by Sanyoku chemical Co., ltd.). In the surface of the zinc coating 10', 5 rectangular areas of 1mm×1mm are arbitrarily selected. EPMA analysis was performed on the selected rectangular area. By image analysis, a region (Zn undetected region) in which Zn was not detected in each rectangular region was specified. In embodiment 2, a region where the detected Zn intensity was 1/16 or less of the intensity of the measured standard sample (pure Zn) was regarded as a Zn undetected region. The ratio (area%) of the total area of Zn unmeasured areas among the 5 rectangular areas with respect to the total area of the 5 rectangular areas is defined as the base steel sheet exposure rate (area%).

The plated steel sheet 1' according to embodiment 2 may be formed with an inorganic coating or an organic-inorganic composite coating between the colored resin layer 11' and the galvanized layer 10' for the purpose of improving corrosion resistance and adhesion. The inorganic coating film has light transmittance. The inorganic coating is, for example, an amorphous silica coating, a zirconia coating, or a phosphate coating. The organic-inorganic composite film has light transmittance. The organic-inorganic composite coating film contains, for example, a silane coupling agent and an organic resin. The organic-inorganic composite film has light transmittance.

[ method of production ]

An example of a method for producing the plated steel sheet 1' according to embodiment 2 will be described below. The manufacturing method described below is an example for manufacturing the plated steel sheet 1' of embodiment 2. Accordingly, the plated steel sheet 1' having the above-described configuration may be manufactured by a manufacturing method other than the manufacturing method described below. However, the manufacturing method described below is a preferable example of the manufacturing method of the plated steel sheet 1' of embodiment 2.

The manufacturing method of embodiment 2 includes: the method comprises a step of preparing a base steel sheet 100' (preparation step: S1 '), a step of forming a galvanized layer 10' on the base steel sheet 100' (galvanization step: S2 '), a step of forming a texture on the surface of the galvanized layer 10' (texturing step: S3 '), and a step of forming a colored resin layer 11' on the plated steel sheet (colored resin layer forming step: S4 '). Hereinafter, each step will be described.

[ preparation step (S1') ]

In the preparation step (S1 '), a base steel sheet 100' is prepared. The base steel sheet 100' may be a steel sheet or may have another shape. If the base steel sheet 100 'is a steel sheet, the base steel sheet 100' may be a hot-rolled steel sheet or a cold-rolled steel sheet.

[ Zinc plating treatment step (S2') ]

In the galvanization process (S2 '), the prepared base steel sheet 100' is subjected to galvanization, and a galvanization layer 10 'is formed on the surface of the base steel sheet 100'.

The galvanization treatment may be performed by a known method. For example, the galvanized layer 10' may be formed by a known electroplating method. In this case, a known bath may be used for the zinc plating bath and the zinc alloy plating bath. Examples of the plating bath include sulfuric acid bath, chloride bath, zincate bath, cyanide bath, pyrophosphoric acid bath, boric acid bath, citric acid bath, other complex bath, and combinations thereof. The zinc alloy plating bath contains, for example, 1 or more kinds of single ions or complex ions selected from Co, cr, cu, fe, ni, P, sn, mn, mo, V, W, zr in addition to Zn ions.

The chemical composition, temperature, flow rate, and plating conditions (current density, current mode, etc.) of the zinc plating bath and the zinc alloy plating bath in the zinc plating process can be appropriately adjusted. The thickness of the zinc plating layer 10' in the zinc plating treatment can be adjusted by adjusting the current value and time within the range of the current density at the time of the zinc plating treatment.

The galvanized layer 10' may also be formed by a hot dip galvanization process or an alloying hot dip galvanization process. In this case, a well-known galvanization bath was also prepared. The zinc plating bath may be composed mainly of Zn, and contains 1 or more elements selected from Mg, al, and Si. If the galvanized layer 10 'is a hot dip galvanized layer, the base steel sheet 100' is immersed in a galvanization bath in which the bath temperature and the chemical composition of the bath are adjusted, and the galvanized layer 10 'is formed on the surface of the base steel sheet 100' (hot dip galvanized layer). If the galvanized layer 10' is an alloyed hot-dip galvanized layer, the base steel sheet 100' on which the hot-dip galvanized layer is formed is subjected to a known heat treatment in a known alloying furnace, and the galvanized layer 10' is made into an alloyed hot-dip galvanized layer. The thickness of the zinc-plated layer 10' in the hot-dip galvanizing process can be adjusted by adjusting the immersion time of the zinc-plating bath and the amount of zinc plating removed by gas wiping. The base steel sheet 100' may be subjected to a known degreasing treatment such as electrolytic degreasing before the plating treatment.

Through the above manufacturing steps, the plated steel sheet 1' having the base steel sheet 100' and the zinc coat layer 10' can be manufactured.

[ texture working procedure (S3') ]

In the texturing step (S3 '), the surface of the galvanized layer 10' of the plated steel sheet is textured 10S 'by performing a known texturing process on the surface of the galvanized layer 10'.

If the texture 10S' is hairline, a known hairline process is performed. The hairline processing method includes: a method of polishing a surface with a known polishing tape to form hairlines, a method of polishing a surface with a known polishing brush to form hairlines, a method of performing roll transfer with a roller having a hairline shape to form hairlines, and the like. The length, depth, and frequency of the hairline can be adjusted by adjusting the particle size of a known polishing belt, the particle size of a known grinding brush, or the surface shape of the roller. That is, the arithmetic average roughness Ra (MC)' and the exposure rate of the base steel sheet can be adjusted by adjusting the particle size of a known polishing belt, the particle size of a known polishing brush, or the surface shape of the roll. In addition, as a method for imparting hairline, it is preferable to form hairline by polishing the surface with a polishing tape or a polishing brush from the viewpoint of surface quality. In this manufacturing method, the step of forming a texture on the surface of the base material is not included, and the surface of the base material has no texture, so that the plated surface before the texturing step (S3') is started is relatively flat. Accordingly, the textured concave portion is formed by polishing or the like in the texturing step (S3'). At this time, the concave portion is formed so that the three-dimensional average roughness Saave' is more than 5nm and 200nm or less.

By the above manufacturing process, the plated steel sheet 1' having the base steel sheet 100' and the plating and zinc layer 10' and having the grain 10S ' extending in one direction formed on the surface of the zinc layer 10' can be manufactured.

[ colored resin layer Forming step (S4') ]

In the colored resin layer forming step (S4 '), a colored resin layer 11' is formed on the galvanized layer 10 'of the plated steel sheet on which the texture 10S' is formed. Hereinafter, the coloring resin layer forming step (S4') will be described in detail.

The paint used for forming the colored resin layer 11' is preferably a paint which, when applied to a plated steel sheet, immediately follows the surface shape of the steel material, and after reflecting the surface shape of the steel material, is slowly leveled. That is, a paint having a low viscosity if the shear rate is high and a high viscosity if the shear rate is low is preferable. Specifically, it is preferable that the viscosity be 10[ Pa.s ] or more at a shear rate of 0.1[1/sec ], and 0.01[ Pa.s ] or less at a shear rate of 1000[1/sec ].

The surface shape of the colored resin layer 11 'can be adjusted by adjusting the shear viscosity of the paint used for forming the colored resin layer 11'.

The method of forming the colored resin layer 11 'on the galvanized layer 10' may be a known method. For example, the viscosity-adjusted paint is applied to the zinc plating layer 10' by a spray method, a roll coating method, a curtain coating method, or a dip coating method. Then, the paint on the galvanized layer 10 'is naturally dried or baked to be dried to form a colored resin layer 11'. The drying temperature, drying time, baking temperature and baking time can be appropriately adjusted. The three-dimensional average roughness Saave ', the minimum thickness DKmin' and the maximum thickness DKmax 'of the colored resin layer 11' can be adjusted by adjusting the shear viscosity of the paint used for forming the colored resin layer 11', the coating amount on the galvanized layer 10', and the like. Further, by adjusting the content of the colorant in the paint, the colorant content CK 'in the colored resin layer 11' can be adjusted.

Through the above manufacturing steps, plated steel sheet 1' of embodiment 2 can be manufactured. The plated steel sheet 1' of embodiment 2 is not limited to the above-described production method, and the plated steel sheet 1' of embodiment 2 may be produced by a production method other than the above-described production method as long as the plated steel sheet 1' having the above-described configuration can be produced. However, the above-described production method is suitably used for producing the plated steel sheet 1' of embodiment 2.

While embodiment 1 and embodiment 2 of the present invention have been described above, the configuration of embodiment 1 and the configuration of embodiment 2 may be appropriately combined. The specific embodiment illustrated in the description of embodiment 1 can be applied to the plated steel sheet of embodiment 2, and vice versa.

In the plated steel sheet 1 of embodiment 1 and the plated steel sheet 1' of embodiment 2 of the present invention, the colored resin layer may be a laminated resin layer. This can further improve the visibility of the surface of the zinc plating layer and suppress the variation in color tone. This is because the partial thickness variation of the colored resin layer can be suppressed by making the colored resin layer a laminate resin layer. The variation in thickness is related to the variation in concentration of the colorant (pigment). Therefore, by suppressing the variation in thickness, the variation in colorant concentration and the variation in color tone can be suppressed.

In addition, the content CK of the colorant in each colored resin layer may be set _N And thickness DK _N The sum of the products of (2) is 15.0 area% μm or less. That is, the content CK of the colorant in each colored resin layer _N And thickness DK _N The following formula may be satisfied.

Σ[k＝1→n](CK _k ×DK _k )≤15.0

This allows the laminated resin layer to be colored to such an extent that the surface energy of the galvanized layer is visually confirmed. Further, the visibility of the surface of the galvanized layer can be further improved, and color variation such as color unevenness and color fluctuation can be sufficiently suppressed. Content CK of colorant in each colored resin layer _N And thickness DK _N The preferable upper limit of the sum of the products of (a) is 12.0 area%. Mu.m, 10.0 area%. Mu.m, or 8.0 area%. Mu.m.

Further, the content (area%) of the colorant of the most-concentrated colored resin layer is defined as "C _1ST "the thickness (μm) of the most dense colored resin layer is defined as" D _1ST The content (area%) of the coloring material of the 2 nd rich-colored resin layer is defined as "C _2ND The thickness (μm) of the 2 nd rich-colored resin layer is defined as "D _2ND In the case of "the laminated resin layer may satisfy the following formula (4).

1.00<(C _1ST ×D _1ST )/(C _2ND ×D _2ND )≤4.00 (4)

That is, the color density index I of the most-concentrated colored resin layer _1ST (＝C _1ST ×D _1ST ) Color density index I of the 2 nd concentrated colored resin layer _2ND (＝C _2ND ×D _2ND ) The ratio of (2) may be 4.00 or less. Hereinafter, (C) _1ST ×D _1ST )/(C _2ND ×D _2ND ) Referred to as "color density ratio RF".

If the color density ratio RF is 4.00 or less, the difference between the color density of the most-concentrated colored resin layer and the color density of the 2 nd-concentrated colored resin layer is not large. Therefore, when the resin layer is colored to such an extent that the surface energy of the galvanized layer is visually confirmed, the surface of the galvanized layer can be visually confirmed, and also, color tone variations such as color unevenness and color fluctuation can be sufficiently suppressed.

The upper limit of the color density ratio RF is preferably 3.80, more preferably 3.50, more preferably 3.00, more preferably 2.50, more preferably 2.00. The closer the color density ratio RF is to 1.00, the more preferable. Therefore, the lower limit of the color density ratio RF is more than 1.00. If the plurality of colored resin layers LK each contain a plurality of different types of colorants having different hues, the RF is 4.00 or less for each colorant having the same hue.

The thickness (total thickness) of the laminated resin layers is not particularly limited, and may be, for example, 10.0 μm or less. If the thickness of the laminated resin layer is 10.0 μm or less, the surface of the galvanized layer can be visually confirmed and also the color tone variation such as color unevenness and color fluctuation can be sufficiently suppressed and the metallic feeling can be sufficiently improved on the premise that the above requirements are satisfied, even if the laminated resin layer is colored to such an extent that the surface of the galvanized layer can be visually confirmed. The upper limit of the thickness of the laminated resin layer is more preferably 9.0 μm, and still more preferably 8.0 μm.

Further, the lower limit of the laminated resin layer is preferably 0.5. Mu.m. If the laminated resin layer is 0.5 μm or more, the corrosion resistance is further improved. The lower limit of the laminated resin layer is more preferably 0.7. Mu.m, still more preferably 1.0. Mu.m, still more preferably 2.0. Mu.m, still more preferably 3.0. Mu.m.

The laminated resin layer 30 may have 1 or more transparent resin layers containing no colorant laminated between the plurality of colored resin layers. The "transparent resin layer" contains a resin having light transmittance and containing no colorant. The resin having light transmittance means that when a design galvanized steel sheet having a laminate resin layer including a colored resin layer containing a colorant and a resin and a transparent resin layer is placed in an environment corresponding to sunlight (illuminance of about 65000 lux) in the morning of a clear day, the surface of the base steel sheet can be visually confirmed. The lamination order of the colored resin layer and the transparent resin layer is not particularly limited. Among the laminated resin layers, a plurality of transparent resin layers may be continuously laminated.

Examples

Example 1

Hereinafter, the effect of one embodiment of the present invention will be described in further detail by way of examples. The conditions in the following examples are one example of conditions used for confirming the possibility and effect of the plated steel sheet 1 according to embodiment 1 of the present invention. Therefore, the present invention is not limited to this condition example. The present invention can employ various conditions within a range that the object of the present invention can be achieved without departing from the gist of the present invention.

Galvanized steel sheets of test numbers described in table 1 were prepared. The base steel sheet of each galvanized steel sheet was set to SPCC defined in JI S G3141 (2017), and the thickness was set to 0.6mm.

Each base material steel sheet is subjected to a base material surface texture forming step, and base material textures (hairlines or matting) of various forms are formed on the base material surface. In test numbers 1, 18, 23, and 28, no texture was formed on the surface of the base material. The column "base material texture" in table 1 shows the presence or absence of the base material surface texture forming step and the type of the base material surface texture forming step in each test number.

Each base steel sheet was subjected to plating pretreatment. Specifically, na having a concentration of 30g/L was used for each steel material ₄ SiO ₄ The temperature of the treatment liquid was 60℃and the current density was 20A/dm ² The electrolytic degreasing was performed under the condition that the treatment time was set to 10 seconds, and the water washing was performed. Immersing the steel material subjected to electrolytic degreasing in H with the concentration of 50g/L at 60 DEG C ₂ SO ₄ The aqueous solution was subjected to water washing for 10 seconds.

The steel sheets of each test number after the plating pretreatment were subjected to the following plating treatments to form zinc plating layers. Specifically, in test numbers 1 to 17, zinc plating layers were formed by electroplating. Specifically, a plating bath containing 1.0mol/L of zinc sulfate heptahydrate, 50g/L of anhydrous sodium sulfate, and having a pH adjusted to 2.0 was prepared. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer (denoted by "EG" in the column of "plating type" in table 1) was formed.

In test numbers 18 to 22, a zinc plating layer containing Ni was formed as a zinc plating layer. Specifically, a total of 1.2mol/L of zinc sulfate heptahydrate and nickel sulfate hexahydrate was preparedThe hydrate and also contained 50g/L anhydrous sodium sulfate, a plating bath adjusted to pH 2.0. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer containing 12% by mass of Ni and the remainder consisting of Zn and impurities (indicated by "Zn-12% Ni" in the column of "plating type" in table 1) was formed.

In test numbers 23 to 27, a zinc plating layer containing Fe was formed as a zinc plating layer. Specifically, a plating bath was prepared which contained 1.2mol/L zinc sulfate heptahydrate and iron (II) sulfate heptahydrate in total and which also contained 50g/L anhydrous sodium sulfate and had a pH adjusted to 2.0. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer containing 14% by mass of Fe and the balance of Zn and impurities (indicated by "Zn-14% Fe" in the column of "plating type" in Table 1) was formed.

In test nos. 28 to 32, as the zinc plating layer, a zinc plating layer containing Co was formed. Specifically, a plating bath was prepared which contained zinc sulfate heptahydrate and cobalt sulfate hexahydrate in total at 1.2mol/L and also contained 50g/L of anhydrous sodium sulfate, and had a pH adjusted to 2.0. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer containing 2% by mass of Co and the balance of Zn and impurities (indicated by "Zn-2% Co" in the column of "plating type" in table 1) was formed.

In the plating treatment of each test number, the plating solution was flowed so that the relative flow rate was 1 m/sec. The composition of the obtained zinc plating layer was measured by the following method. The steel sheet on which the plating layer was formed was immersed in 10 mass% hydrochloric acid to which an inhibitor (manufactured by Nikki chemical Co., ltd. No. 700AS) was added, and the zinc plating layer was dissolved and peeled. Then, the solution in which the zinc plating layer was dissolved was subjected to ICP analysis to confirm the composition of the zinc plating layer.

After forming the zinc plating layer, the zinc plating surface texture forming step was performed in test numbers 2 to 4, 6 to 17, 19 to 22, 24 to 27, and 29 to 32, and the polishing step was further performed, and the tips of the protruding portions of the zinc plating layer were polished and ground. In the galvanized surface texture forming step and the polishing step, polishing tapes having various particle sizes are pressed against the tips of the protrusions of the galvanized layer, and the pressing force and the number of times of polishing are changed to conduct polishing and polishing. In the galvanized surface texture forming step, a polishing tape having a coarser grain size than that in the polishing step is used. In test numbers 1, 5, 18, 23, and 28, the galvanized surface texture forming step and the polishing step were not performed. The presence or absence of the zinc plating surface texture forming step and the type of the zinc plating surface texture forming step in each test number are shown in the column of "plating texture" in table 1.

Note that, even in the case of a plated steel sheet obtained without the galvanized surface texture forming step, the plated texture is provided only when the base material texture is formed through the base material surface texture forming step. This is because, when a galvanized layer is formed by performing a galvanization treatment on a base steel sheet having a base texture, a plated texture along the base texture is formed on the surface of the galvanized layer. For example, the plated steel sheet of test No. 5 was produced without going through the galvanization surface texture forming step. Thus, with respect to test No. 5, the "no" is described in the column of "plating texture" in table 1. However, since the plated steel sheet of test No. 5 was produced by the base material surface texture forming step, it had a plated texture.

The galvanized steel sheets with hairlines (test numbers 2 to 17, 19 to 22, 24 to 17, 29 to 32) and the galvanized steel sheets without hairlines (test numbers 1, 18, 23, 28) were formed with a colored resin layer. In the colored resin layer, as an organic resin, a paint having various concentrations and viscosities was prepared in which a urethane resin (manufactured by ADEK a, HUX-232, inc.) was dispersed in water. Pigments (carbon black) of various concentrations are added to the paint. The carbon black was used under the trade name #850 manufactured by Mitsubishi chemical corporation.

The coating was applied to the surface of the zinc coating layer of each test number zinc-coated steel sheet by dipping the coating material with a roller. The coated paint is baked and dried. Specifically, the galvanized steel sheet coated with the coating material is charged into a furnace maintained at 250 ℃. Until the temperature of the galvanized steel sheet reaches 210 ℃, the galvanized steel sheet is kept in the furnace for 1 to 5 minutes. After holding, the galvanized steel sheet was taken out of the furnace and cooled.

The viscosity of the coating was adjusted using a viscosity modifier (trade name: BYK-425, manufactured by BYK). Specifically, the viscosity of the dope is adjusted so that the dope viscosity is 10 (Pa.s) or more at a shear rate of 0.1 (1/sec) and 0.01 (Pa.s) or less at a shear rate of 1000 (1/sec). Through the above steps, a colored resin layer was formed on the galvanized layer of each test number.

By the above production method, galvanized steel sheets of each test number were produced. In test No. 18, a pigment-free urethane resin (manufactured by ADEKA, HUX-232, co., ltd.) was applied between the colored resin layer and the galvanized layer to a thickness of 0.5. Mu.m. Then, a colored resin layer was formed.

[ evaluation test ]

[ three-dimensional average roughness Sas at the bottom of concave portion and three-dimensional average roughness Sah at the top of convex portion measurement test ]

The maximum three-dimensional average roughness of the texture (hairline) of the galvanized surface of each test-numbered galvanized steel sheet was measured by the following method. First, a solvent (trade name: neorever S-701, manufactured by Sanyoku chemical Co., ltd.) that does not attack the galvanized layer was used, and the colored resin layer of the galvanized steel sheet was removed. In the surface of the zinc plating layer, 1 length of 1000 μm is arbitrarily selected in the 2 nd direction perpendicular to the extending direction (1 st direction) of the texture (hairline). The roughness profile of the texture was measured over a selected length of 1000 μm. The roughness profile was measured using a three-dimensional surface roughness measuring machine (SURFCOM 1500DX3 manufactured by tokyo precision).

As shown in fig. 6A, in a plan view of the galvanized surface, a 1 μm×1 μm minute concave portion bottom region centered on each concave portion bottom point PREk (k is 1 to 10) defined is designated. The three-dimensional average roughness Sa was measured in each of the 10 specified minute recess bottom regions. The three-dimensional average roughness Sa is an arithmetic average roughness specified in ISO 25178, which expands Ra (arithmetic average roughness of a line) specified in JIS B0601 (2013) to a plane. The arithmetic average of the 10 three-dimensional average roughness Sa obtained by the measurement was defined as the recess bottom three-dimensional average roughness Sas (μm).

Similarly, attention is paid to each convex portion 10CO in the roughness profile obtained by measurement. In each convex portion 10CO, the highest position is defined as a convex portion apex PCO. Among the plurality of convex portion apexes PCO in the roughness profile in the range of 1000 μm in length, 10 convex portion apexes PCO1, PCO2, …, PCO10 are designated in order from highest to lowest from the highest convex portion apex PCO 1.

As shown in fig. 6B, in a plan view of the surface of the galvanized layer, a 1 μm×1 μm minute convex top region centered on each of the defined convex portion vertices PCOk (k is 1 to 10) is designated. The three-dimensional average roughness Sa was measured in each of the 10 specified minute convex top regions. The three-dimensional average roughness Sa is an arithmetic average roughness specified in ISO 25178, which expands Ra (arithmetic average roughness of a line) specified in JIS B0601 (2013) to a plane. The arithmetic average of the measured 10 three-dimensional average roughness Sa was defined as the convex top three-dimensional average roughness Sah (μm).

[ Dkmin, dkmax assay ]

The thicknesses (DKmin, DKmax) of the colored resin layers of the galvanized steel sheets of each test number were measured by the following methods. Samples having a cross section perpendicular to the 1 st direction of the grain (hairline) on the surface were collected from the galvanized steel sheets of each test number. An observation section of a range of 100 μm in length in a direction perpendicular to an extending direction of the texture (hairline) in the sample was observed with a Scanning Electron Microscope (SEM) in a reflected electron image (BSE) of 2000 times. In the observation section, the thickness of the colored resin layer was measured at a pitch of 0.5 μm in the direction WD. In the measured thickness, the minimum thickness is defined as the minimum thickness Dkmin (μm). In the measured thickness, the maximum thickness is defined as the maximum thickness Dkmax (μm).

[ colorant content CK measurement test ]

The colorant content (area%) in the colored resin layer of each test-numbered galvanized steel sheet was determined by the following method. Samples were collected having a cross section perpendicular to the 1 st direction of the texture (hairline) on the surface. In the sample, a cross section perpendicular to the 1 st direction of the texture (hairline) was taken as an observation surface. Using FIB, a film sample capable of observing the colored resin layer and the galvanized layer of the observation surface was prepared from the sample. The film thickness of the thin film sample was set to 150nm. Using TEM, a visual field having a length of 3 μm in a direction perpendicular to the thickness direction of the colored resin layer (i.e., the 2 nd direction WD) and a length including the entire colored resin layer in the thickness direction of the colored resin layer (i.e., the 3 rd direction TD) was observed on the observation surface of the prepared film sample. In TEM observation, the resin and pigment in the colored resin layer can be identified by contrast. The total area A1 (μm) of the plurality of pigments in the colored resin layer in the observation cross section was determined ² ). And the area (. Mu.m) of the colored resin layer in the observation cross section was determined ² ). The colorant content (area%) in the colored resin layer 11 was determined by the following formula based on the obtained total area A1 and area A0.

CK＝A1/A0×100

[ roughness Ra (CC) of colored resin layer and Ra (CL) measurement test ]

The roughness Ra (CC) and Ra (CL) of the colored resin layer of each test-numbered galvanized steel sheet were obtained by the following methods.

The surface roughness Ra (CL) was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). On the surface of the colored resin layer, 10 arbitrary positions were set as measurement positions. In each measurement position, the arithmetic average roughness Ra was measured with an evaluation length extending in the 1 st direction of the texture (hairline). The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a three-dimensional surface roughness measuring machine (SURFCOM 1500D X3, manufactured by Tokyo precision Co., ltd.) at a measuring speed of 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CL).

Similarly, the surface roughness Ra (CC) was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). On the surface of the colored resin layer, 10 arbitrary positions were set as measurement positions. In each measurement position, the arithmetic average roughness Ra was measured with an evaluation length extending in the 2 nd direction of the texture (hairline). The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using the three-dimensional surface roughness measuring machine, and the measurement speed was set to 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CC).

[ test for measuring surface roughness Ra (MC) of Zinc-plated layer ]

The surface roughness Ra (MC) of the galvanized layer of each test-numbered galvanized steel sheet was determined by the following method.

The surface roughness Ra (MC) was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). The colored resin layer of the galvanized steel sheet was removed using a solvent (trade name: neorever S-701, manufactured by Sanyoku chemical Co., ltd.) which did not attack the galvanized layer. In the texture (hairline) of the galvanized layer after the colored resin layer was removed, 10 arbitrary positions were taken as measurement positions. In each measurement position, the arithmetic average roughness Ra was measured with an evaluation length extending in the 2 nd direction. The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using the three-dimensional surface roughness measuring machine, and the measurement speed was set to 0.5mm/sec. From among the 10 calculated arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (MC) (μm).

[ test for measuring Exposure Rate of base Steel sheet ]

The exposure rate of the base steel sheet of each test-numbered galvanized steel sheet was measured by the following method. A galvanized steel sheet from which the colored resin layer was removed was prepared. In the surface of the zinc coating layer, 5 rectangular areas of 1mm×1mm are arbitrarily selected. EPMA analysis was performed on the selected rectangular area. By image analysis, a region (Zn undetected region) in which Zn was not detected in each rectangular region was specified. A region where the detected strength of Zn was 1/16 or less of the strength of the measured standard sample (pure Zn) was regarded as a Zn undetected region. The ratio (area%) of the total area of Zn unmeasured areas among the 5 rectangular areas with respect to the total area of the 5 rectangular areas is defined as the base steel sheet exposure rate (area%).

[ texture visual confirmation test ]

The galvanized steel sheets of each test number were placed in an environment corresponding to solar light (illuminance about 65000 lux) in the morning on a sunny day. And, various modifications are made to the angles of the light source, the steel plate, and the line of sight to observe to confirm whether the texture can be confirmed by naked eyes. If the texture could be visually confirmed at all angles in the range of 5 ° to 80 ° with respect to the perpendicular direction of the steel sheet surface, it was evaluated as a very good pass (evaluation "a" in table 1). Further, if some of the angles in the range of 5 ° to 80 ° with respect to the vertical direction of the steel sheet surface were able to confirm the texture with naked eyes, the evaluation was acceptable (evaluation "B" in table 1). On the other hand, if the texture could not be confirmed with the naked eye at all, the evaluation was failed (evaluation "C" in table 1).

[ brightness measurement test ]

For each test number of galvanized steel sheets, the brightness L was measured by the following method ^* The value serves as a reference value. For the measurement, a color meter (trade name: CM-2600 d) manufactured by Konikoku Meida Co., ltd was used. In the measurement, a CIELAB color was obtained by the SCI method using CIE standard illuminant D65 as illuminant, with a viewing angle of 10 degrees ^* Values.

Here, the CIE standard illuminant D65 is defined in JIS Z8720 (2000), "a color measuring illuminant (standard light) and a standard illuminant", and the same is defined in ISO 10526 (2007). CIE is a acronym for Co mmission Internationale de l' Eclairage, representing the International Commission on illumination. CIE standard illuminant D65 is used when representing object colors under daylight illumination. The viewing angle of 10 ° is defined in JIS Z8723 (2009) "visual comparison method of surface color", and the same is defined in ISO/DIS 3668.

The SCI method is also called a method involving specular reflection light, and means a method for measuring color without removing specular reflection light. The brightness measurement method according to the SCI method is specified in JIS Z8722 (2009). In the SCI method, since measurement is performed without removing specular reflection light, the color of an actual object is measured.

CIELAB indicates a uniform color space prescribed in JIS Z8781 (2013) recommended in 1976 for measuring a color difference caused by a difference between a perception and a measurement value based on a device. L for 3 coordinates of CI ELAB ^* Value, a ^* Value, b ^* The value represents. L (L) ^* The value represents brightness and is represented by 0 to 100. L (L) ^* The value of 0 represents black, L ^* A value of 100 indicates a diffuse reflection of white.

[ Corrosion resistance evaluation test ]

The corrosion resistance (long-term corrosion resistance) of each test-number galvanized steel sheet was evaluated by the following method. From each test number of galvanized steel sheets, 75mm×100mm test pieces were collected. The cut surface and the back surface of the test piece were protected by sealing with an adhesive tape. Then, a salt water spray test of 5% NaCl maintained at 35℃was performed in accordance with JIS Z2371 (2015). The test was carried out for 240 hours, and the rust rate after the test was obtained. If the rust ratio is 0%, the corrosion resistance evaluation is determined as a, and if the rust ratio is more than 0% and not more than 5%, the corrosion resistance evaluation is determined as B, and the corrosion resistance is evaluated as good. If the rust ratio is greater than 5%, the corrosion resistance evaluation is determined to be C. However, the present invention has a major problem in that the visibility of texture is improved. Therefore, even if the corrosion resistance was evaluated as C, the example of the test number that was qualified in the texture visual confirmation test was judged as the example of the present invention.

[ adhesion test ]

The adhesion of the colored resin layer of each test-numbered galvanized steel sheet was evaluated by the following method. Test pieces 50mm wide by 50mm long were prepared from each test-numbered galvanized steel sheet. The test piece obtained was subjected to 180 ° bending. After the bending process, an adhesive tape peeling test was performed on the outside of the bent portion. The appearance of the tape-released portion was observed with a magnifying glass having a magnification of 10 times. Then, the evaluation was performed in accordance with the following evaluation criteria. The bending process was performed in an atmosphere at 20℃with a 0.6mm spacer sandwiched therebetween. The results obtained are shown in table 1 below.

(evaluation criterion)

A: no peeling of the coating film was observed

B: peeling of a very small portion of the coating film was observed (peeling area. Ltoreq.2%)

C: peeling of a part of the coating film was observed (2% < peeling area. Ltoreq.20%)

D: peeling of the coating film was observed (peeling area > 20%)

If the evaluation is A to C, it is judged that the adhesion is excellent. If the evaluation is D, it is judged that the adhesion is low. However, the present invention has a major problem in that the visibility of texture is improved. Therefore, even if the adhesion was determined as D, the example of the test number that was qualified in the texture visual inspection test was determined as the example of the present invention.

[ Metal feel evaluation test ]

The metallic feel of each test number of galvanized steel sheets was measured by the following method. At any point of each test number of the plated steel sheet 1, the gloss G60 (Gl) in the direction parallel to the texture (hairline) and the gloss G60 (Gc) in the direction straight to the texture (hairline) were measured with a gloss meter. The gloss meter used was a gloss meter (trade name: UGV-6P) manufactured by Suga tester Co. Based on the obtained gloss Gl and gloss Gc, gc/Gl is obtained. If the texture can be confirmed by the naked eye and Gc/Gl.ltoreq.0.70, it is judged that an excellent metallic feeling is obtained (evaluation "A" in Table 1). If the texture can be visually confirmed and 0.70< gc/gl.ltoreq.0.90, it is judged that a good metallic feeling was obtained (evaluation "B" in table 1). If the texture could not be confirmed by the naked eye or if the texture was 0.90< gc/Gl although it could be confirmed by the naked eye, it was judged that the metallic feeling was not obtained (evaluation "C" in table 1). However, the present invention has a major problem in that the visibility of texture is improved. Therefore, even if the metallic feeling is judged as C, the example of the test number that is qualified in the texture visual confirmation test is judged as the example of the present invention.

[ evaluation results ]

Referring to Table 1, in test numbers 4, 5, 8 to 17, 20 to 22, 25 to 27, and 30 to 32, the three-dimensional average roughness Sas of the bottom of the concave portion was more than 200nm and not more than 2000 nm. In these test numbers, F1 was 15.0 or less and F2 was greater than 1.0. Therefore, even if the brightness is 50 or less, the texture can be visually confirmed (evaluation a or B) in the texture visual confirmation test for these test numbers. And the adhesion was also excellent for these test numbers. The corrosion resistance of test No. 2 was slightly lower than that of the other invention examples except that in embodiment 1, but the metallic feeling was high and the appearance was good in embodiment 2.

In test numbers 4, 5, 8 to 17, 20 to 22, 25 to 27, and 30 to 32, the three-dimensional average roughness Sah of the top of the convex portion was greater than 5nm and equal to or less than 200nm in test numbers other than test number 5. Therefore, test numbers 4, 10 to 17, 20 to 22, 25 to 27, and 30 to 32 were lower in brightness than test number 5, but the texture could be visually confirmed.

In test numbers 4, 5, 8 to 17, 20 to 22, 25 to 27, and 30 to 32, the exposure rate of the base steel sheet in test numbers other than test numbers 4 and 10 was less than 5%. Therefore, the test numbers 5, 8, 9, 11 to 17, 20 to 22, 35 to 27, and 30 to 32 had a rust ratio of less than 5% in the corrosion resistance evaluation test, and sufficient corrosion resistance was obtained (evaluation a or B).

On the other hand, in test No. 1, no plating texture was formed. Therefore, the maximum thickness DKmax, the minimum thickness DKmin, and the colorant content CK of the colored resin layer do not satisfy formula (2). Further, the surface roughness Ra (CL) and the surface roughness Ra (CC) do not satisfy the formula (3). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test nos. 3 and 6, the minimum thickness DKmin of the colored resin layer and the colorant content CK in the colored resin layer do not satisfy formula (1). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 7, the maximum thickness DKmax, the minimum thickness DKmin, and the colorant content CK of the colored resin layer do not satisfy formula (2). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 18, no plating texture was formed. Therefore, the maximum thickness dkmax, the minimum thickness DKmin, and the colorant content CK of the colored resin layer do not satisfy formula (2). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 19, the minimum thickness DKmin of the colored resin layer and the colorant content CK in the colored resin layer do not satisfy formula (1). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 23, no plating texture was formed. Therefore, the maximum thickness dkmax, the minimum thickness DKmin, and the colorant content CK of the colored resin layer do not satisfy formula (2). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 24, the minimum thickness DKmin of the colored resin layer and the colorant content CK in the colored resin layer do not satisfy formula (1). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 28, no plating texture was formed. Therefore, the maximum thickness dkmax, the minimum thickness DKmin, and the colorant content CK of the colored resin layer do not satisfy formula (2). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 29, the minimum thickness DKmin of the colored resin layer and the colorant content CK in the colored resin layer do not satisfy formula (1). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In the above, embodiment 1 of the present invention has been described. However, the above-described embodiments are merely examples for implementing the present invention. Therefore, the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications within the scope of the gist thereof.

Example 2

Next, various examples manufactured to confirm the possibility and effect of the plated steel sheet 1' according to embodiment 2 of the present invention will be described.

Galvanized steel sheets of test numbers described in table 2 were prepared. The steel material (steel sheet) of each galvanized steel sheet was SPCC defined in JIS G3141 (2017), and the thickness was 0.6mm.

Each steel material was subjected to plating pretreatment. Specifically, na having a concentration of 30g/L was used for each steel material ₄ SiO ₄ The temperature of the treatment liquid was 60℃and the current density was 20A/dm ² The electrolytic degreasing was performed under the condition that the treatment time was set to 10 seconds, and the water washing was performed.Immersing the steel material subjected to electrolytic degreasing in H with the concentration of 50g/L at 60 DEG C ₂ SO ₄ The aqueous solution was subjected to water washing for 10 seconds.

The steel materials of each test number after the plating pretreatment were subjected to the following plating treatments to form zinc plating layers. Specifically, in test numbers 1 'to 16', zinc plating layers were formed by electroplating. Specifically, a plating bath containing 1.0mol/L of zinc sulfate heptahydrate, 50g/L of anhydrous sodium sulfate, and adjusted to pH 2.0 was prepared. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer (denoted by "EG" in the column of "plating type" in table 2) was formed.

In test numbers 17 'to 20', a zinc plating layer containing Ni was formed as a zinc plating layer. Specifically, a plating bath was prepared which contained zinc sulfate heptahydrate and nickel sulfate hexahydrate in total at 1.2mol/L and also contained 50g/L of anhydrous sodium sulfate, and which had been adjusted to pH 2.0. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer containing 12% by mass of Ni and the remainder consisting of Zn and impurities (indicated by "Zn-12% Ni" in the column of "plating type" in table 2) was formed.

In test numbers 21 'to 24', a zinc plating layer containing Fe was formed as a zinc plating layer. Specifically, a plating bath adjusted to pH 2.0 was prepared which contained zinc sulfate heptahydrate and iron (II) sulfate heptahydrate in total at 1.2mol/L and also contained 50g/L of anhydrous sodium sulfate. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer containing 14% by mass of Fe and the balance of Zn and impurities (indicated by "Zn-14% Fe" in the column of "plating type" in table 2) was formed.

In test numbers 25 'to 28', the test numbers were used asAnd forming a zinc plating layer containing Co. Specifically, a plating bath was prepared which contained zinc sulfate heptahydrate and cobalt sulfate hexahydrate in total at 1.2mol/L and also contained 50g/L of anhydrous sodium sulfate, and had a pH adjusted to 2.0. In the plating, the bath temperature was set to 50℃and the current density was set to 50A/dm ² . The plating time was adjusted so that the adhesion amount was 30.0g/m ² Left and right. Through the above steps, a zinc plating layer containing 2% by mass of Co and the balance of Zn and impurities (indicated by "Zn-2% Co" in the column of "plating type" in table 2) was formed.

After the zinc coating layer was formed, the galvanized steel sheet was textured in the rolling direction RD of the steel sheet in test numbers 2 'to 16', 18 'to 20', 22 'to 24', 26 'to 28' to impart hairlines to the surface of the zinc coating layer. Specifically, various kinds of hairlines are imparted by pressing various kinds of abrasive papers having various particle sizes against the surface of the zinc plating layer and changing the pressing force and the number of times of polishing. The column "texture" in table 2 shows the presence or absence of texture processing and the type of texture processing in each test number.

The galvanized steel sheets with hairlines (test numbers 2 'to 16', 18 'to 20', 22 'to 24', 26 'to 28'), and the galvanized steel sheets without hairlines (test numbers 1', 17', 21 'and 25') were formed with a colored resin layer. In the colored resin layer, as an organic resin, a paint having various concentrations and viscosities was prepared in which a urethane resin (manufactured by ADEKA, HUX-232, inc.) was dispersed in water. Various concentrations of colorants (carbon black) were added to the coating. The carbon black was used under the trade name #850 manufactured by Mitsubishi chemical corporation.

The coating was applied to the surface of the zinc coating layer of each test number zinc-coated steel sheet by dipping the coating material with a roller. And baking and drying the coated paint. Specifically, the galvanized steel sheet coated with the coating material was charged into a furnace maintained at 250 ℃. Until the temperature of the galvanized steel sheet reaches 210 ℃, the galvanized steel sheet is kept in the furnace for 1 to 5 minutes. After holding, the galvanized steel sheet was taken out of the furnace and cooled.

By the above production method, galvanized steel sheets of each test number were produced. In test No. 16', a urethane resin (manufactured by ADEKA, HUX-232, co., ltd.) containing no colorant was applied between the colored resin layer and the galvanized layer to a thickness of 0.5. Mu.m. Then, a colored resin layer was formed.

[ evaluation test ]

[ three-dimensional average roughness Saave' measurement test ]

The maximum three-dimensional average roughness of the texture (hairline) of the surface of the galvanized layer of each test-number galvanized steel sheet was measured by the following method. First, a solvent (trade name: neorever S-701, manufactured by Sanyoku chemical Co., ltd.) that does not attack the galvanized layer was used, and the colored resin layer of the galvanized steel sheet was removed. In the surface of the zinc plating layer, a range of 1000 μm in length in a direction perpendicular to the extending direction of the texture (hairline) is arbitrarily selected. The roughness profile of the texture was measured over a selected length of 1000 μm. The roughness profile was measured using a three-dimensional surface roughness measuring machine (SURFCOM 1500DX3 manufactured by tokyo precision). Among the positions on the measured roughness profile, 10 positions with low heights are designated in order from the beginning of the low height, and the positions with low heights are defined as concave bottom points PRE1', PRE2', …, PRE10' in order from the beginning of the low height. Among the positions on the roughness profile obtained by measurement, 10 high positions are designated in order from the high position, and the convex portion vertices PCO1', PCO2', …, and PCO10' are defined in order from the high position.

As shown in fig. 14A, in a plan view of the surface of the zinc plating layer, a 1 μm×1 μm minute recessed area centered on each recessed bottom point PREk' (k is 1 to 10) defined is designated. Similarly, as shown in fig. 14B, in a plan view of the surface of the galvanized layer, a 1 μm×1 μm minute convex region centered on each of the defined convex portion vertices PCOk' (k is 1 to 10) is designated.

The three-dimensional average roughness Sa' was measured in 10 fine concave portions areas and 10 fine convex portions areas designated by the above method. The assignment of the minute concave region and the minute convex region and the measurement of the three-dimensional average roughness Sa' were performed using a laser microscope (trade name: VK-9710) manufactured by Keyence, inc. In VK-9710, the display resolution in the height direction was 1nm or more, and the display resolution in the width direction was 1nm or more. The arithmetic average value of the measured 20 (10 minute concave regions and 10 minute convex regions) three-dimensional average roughness Sa 'was defined as three-dimensional average roughness Saave'.

[ Dkmin ', dkmax' assay ]

The thicknesses (Dkmin ', dkmax') of the colored resin layers of the galvanized steel sheets of the respective test numbers were measured by the following methods. Samples having a cross section perpendicular to the extending direction of the texture (hairline) on the surface were collected from the galvanized steel sheets of each test number. An observation section of a range of 100 μm in length in a direction perpendicular to an extending direction of the texture (hairline) in the sample was observed with a Scanning Electron Microscope (SEM) in a reflected electron image (BSE) of 2000 times. In the observation section, the thickness of the colored resin layer was measured at a pitch of 0.5 μm in the direction WD'. In the measured thickness, the minimum thickness is defined as the minimum thickness Dkmin' (μm). In the measured thickness, the maximum thickness is defined as the maximum thickness DK max' (μm).

[ colorant content CK' measurement test ]

The colorant content (area%) in the colored resin layer of each test-numbered galvanized steel sheet was determined by the following method. Samples were collected which had a cross section on the surface perpendicular to the direction of extension of the texture (hairline). In the sample, a cross section perpendicular to the extending direction of the texture (hairline) was used as an observation surface. Using FIB, a film sample capable of observing the colored resin layer and the galvanized layer of the observation surface was prepared from the sample. The film thickness of the thin film sample was set to 150nm. In the observation surface of the prepared film sample, a field of view having a length of 3 μm in a direction perpendicular to the thickness direction of the colored resin layer (i.e., direction WD ') and having a length including the entire colored resin layer in the thickness direction of the colored resin layer (i.e., direction TD') was observed using TEM. In TEM observation, the resin and the colorant in the colored resin layer can be identified by contrast. The total area A1' (μm) of the plurality of colorants in the colored resin layer in the observation cross section was obtained ² ). Then, the area A0' (μm) of the colored resin layer in the observation cross section was obtained ² ). The colorant content (area%) in the colored resin layer 11 was determined by the following formula based on the obtained total area A1 'and area A0'.

CK’＝A1’/A0’×100

[ roughness Ra (CC) 'of colored resin layer and Ra (CL)' measurement test ]

The roughness Ra (CC) 'and Ra (CL)' of the colored resin layer of each test-numbered galvanized steel sheet were determined by the following methods.

The surface roughness Ra (CL)' was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). On the surface of the colored resin layer, 10 arbitrary positions were set as measurement positions. In each measurement position, the arithmetic average roughness Ra was measured with an evaluation length extending in the extending direction of the texture (hairline). The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using a three-dimensional surface roughness measuring machine (SURFCOM 1500D X3, manufactured by Tokyo precision Co., ltd.) at a measuring speed of 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CL)'.

Similarly, the surface roughness Ra (CC)' was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). On the surface of the colored resin layer, 10 arbitrary positions were set as measurement positions. At each measurement position, the arithmetic average roughness Ra was measured with an evaluation length extending in a direction perpendicular to the extending direction of the texture (hairline). The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using the three-dimensional surface roughness measuring machine, and the measurement speed was set to 0.5mm/sec. From the obtained 10 arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (CC)'.

[ surface roughness Ra (MC)' measurement test of Zinc coating ]

The surface roughness Ra (MC)' of the galvanized layer of each test-number galvanized steel sheet was determined by the following method.

The surface roughness Ra (MC)' was measured by the method for measuring the arithmetic average roughness specified in JIS B0601 (2013). The colored resin layer of the galvanized steel sheet was removed using a solvent (trade name: neorever S-701, manufactured by Sanyoku chemical Co., ltd.) which did not attack the galvanized layer. In the texture (hairline) of the galvanized layer after the colored resin layer was removed, 10 arbitrary positions were taken as measurement positions. At each measurement position, the arithmetic average roughness Ra was measured with an evaluation length extending in a direction perpendicular to the extending direction of the texture (hairline). The evaluation length was set to 5 times the reference length (cut-off wavelength). The arithmetic average roughness Ra was measured using the three-dimensional surface roughness measuring machine, and the measurement speed was set to 0.5mm/sec. From among the 10 calculated arithmetic average roughnesses Ra, the largest arithmetic average roughing Ra, the 2 nd largest arithmetic average roughing Ra, the smallest arithmetic average roughing Ra, and the 2 nd smallest arithmetic average roughing Ra were removed, and the arithmetic average of the remaining 6 arithmetic average roughing Ra was defined as the surface roughness Ra (MC)' (μm).

[ test for measuring Exposure Rate of base Steel sheet ]

[ texture visual confirmation test ]

[ brightness measurement test ]

For each test number of galvanized steel sheets, the brightness L was measured by the following method ^* The value serves as a reference value. The measurement was performed using a method manufactured by Cornicarbada Co., ltdColor measuring instrument (trade name: CM-2600 d). In the measurement, a CIELAB color was obtained by the SCI method using CIE standard illuminant D65 as illuminant, with a viewing angle of 10 degrees ^* Values.

Here, CIE standard illuminant D65 is defined in JIS Z8720 (2000 "), a color measuring illuminant (standard light) and a standard illuminant", and ISO 10526 (2007) is defined in the same manner. CIE is a acronym for Co mmission Internationale de l' Eclairage, representing the International Commission on illumination. CIE standard illuminant D65 is used when representing object colors under daylight illumination. The viewing angle of 10 ° is defined in JIS Z8723 (2009) "visual comparison method of surface color", and the same is defined in ISO/DIS 3668.

[ Corrosion resistance evaluation test ]

The corrosion resistance (long-term corrosion resistance) of each test-number galvanized steel sheet was evaluated by the following method. From each test number of galvanized steel sheets, 75mm×100mm test pieces were collected. The cut surface and the back surface of the test piece were protected by sealing with an adhesive tape. Then, a salt water spray test of 5% NaCl maintained at 35℃was performed in accordance with JIS Z2371 (2015). The test was carried out for 240 hours, and the rust rate after the test was obtained. If the rust ratio is 0%, the corrosion resistance evaluation is determined as a, and if the rust ratio is more than 0% and not more than 5%, the corrosion resistance evaluation is determined as B, and the corrosion resistance is evaluated as good. If the rust ratio is greater than 5%, the corrosion resistance evaluation is determined to be C. However, the main problem of the present invention is to improve the aesthetic properties such as the visibility of texture. Therefore, even if the corrosion resistance was evaluated as C, the example of the test number that was qualified in the texture visual confirmation test was judged as the example of the present invention.

[ Metal feel evaluation test ]

The metallic feel of each test number of galvanized steel sheets was measured by the following method. At any point of each test number of the plated steel sheet 1, the gloss G60 (Gl) in the direction parallel to the texture (hairline) and the gloss G60 (Gc) in the direction straight to the texture (hairline) were measured with a gloss meter. The gloss meter used was a gloss meter (trade name: UGV-6P) manufactured by Suga tester Co. Based on the obtained gloss Gl and gloss Gc, gc/Gl is obtained. If the texture can be confirmed by the naked eye and Gc/Gl.ltoreq.0.70, it is judged that an excellent metallic feeling is obtained (evaluation "A" in Table 1). If the texture can be visually confirmed and 0.70< gc/gl.ltoreq.0.90, it is judged that a good metallic feeling was obtained (evaluation "B" in table 1). If the texture could not be visually confirmed, or if the texture was 0.90< gc/Gl even though it could be visually confirmed, it was judged that the metallic feeling was not obtained (evaluation "C" in table 1). However, the present invention has a major problem in that the visibility of texture is improved. Therefore, even if the metallic feeling is judged as C, the example of the test number that is qualified in the texture visual confirmation test is judged as the example of the present invention.

[ evaluation results ]

Referring to table 1, in test numbers 3', 6' to 16', 19', 20', 23', 24', 27' and 28', the three-dimensional average roughness Saave ' is more than 5nm and 200nm or less, and the minimum thickness DKmi ' of the colored resin layer and the content CK ' of the colorant in the colored resin layer satisfy formula (1 '). Further, the maximum thickness DKmax ', the minimum thickness DKmin', and the colorant content CK 'of the colored resin layer satisfy the formula (2'). Thus, in the texture visual confirmation test, the texture can be visually confirmed (evaluation a or B).

In the test numbers 3', 6' to 16', 19', 20', 23', 24', 27' and 28', the exposure rate of the base steel sheet was less than 5% in the test numbers other than the test number 3'. Therefore, in the corrosion resistance evaluation test, the rust ratio was less than 5%, and sufficient corrosion resistance was obtained (evaluation a).

On the other hand, in test No. 1', the three-dimensional average roughness Saave' was too large. Further, the maximum thickness DKmax ', the minimum thickness DKmin', and the colorant content CK 'of the colored resin layer do not satisfy the formula (2'). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 2', the minimum thickness DKmin' of the colored resin layer and the content CK 'of the colorant in the colored resin layer do not satisfy the formula (1'). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 4', the minimum thickness DKmin' of the colored resin layer and the content CK 'of the colorant in the colored resin layer do not satisfy the formula (1'). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 5', the maximum thickness DKmax ', the minimum thickness DKmin ', and the colorant content CK ' of the colored resin layer do not satisfy the formula (2 '). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 17', the maximum thickness DKmax ', the minimum thickness DKmin ', and the colorant content CK ' of the colored resin layer do not satisfy the formula (2 '). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 18', the minimum thickness DKmin' of the colored resin layer and the content CK 'of the colorant in the colored resin layer do not satisfy the formula (1'). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 21', the maximum thickness DKmax ', the minimum thickness DKmin ', and the colorant content CK ' of the colored resin layer do not satisfy the formula (2 '). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 22', the minimum thickness DKmin' of the colored resin layer and the content CK 'of the colorant in the colored resin layer do not satisfy the formula (1'). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 25', the maximum thickness DKmax ', the minimum thickness DKmin ', and the colorant content CK ' of the colored resin layer do not satisfy the formula (2 '). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

In test No. 26', the minimum thickness DKmin' of the colored resin layer and the content CK 'of the colorant in the colored resin layer do not satisfy the formula (1'). Therefore, in the texture visual confirmation test, the texture cannot be visually confirmed (evaluation C).

Example 3

In test numbers 12, 14 to 16, 20 to 21, 25 to 26, 30 to 31, 13 'to 16', 19 'to 20', 23 'to 24', 27 'to 28' of examples 1 and 2, the same paint was used, and the resin layers were coated in several times so that the total film thickness of the colored resin layers was the same, to thereby obtain laminated resin layers. The test numbers coated with the laminated resin are shown in tables 3A and 3B in the form of # added to the original test numbers. In the laminated resin layer forming step, a manufacturing line including a resin layer manufacturing apparatus in which a colored resin coating apparatus and a baking oven are combined is used. In the case of laminating resins, a resin layer manufacturing process using the resin layer manufacturing apparatus is performed a plurality of times. In test numbers 15# and 15' # the transparent resin layer containing no coloring pigment was laminated as the third layer, and the number of laminated resin layers was set to 3 (the number of laminated resin layers in the column "laminated resin layers" is described as "3"). In test numbers 16# and 16' # the transparent resin layer containing no coloring pigment was laminated as the first layer, and the number of laminated resin layers was set to 3 (described as "3" in the "number of laminated layers" column of the "laminated resin layer"). The number of colored resin layers in the laminated resin layers was set to 2 in the test number for the formation of other laminated resins (the number of colored resin layers in the "laminated resin layers" column is described as "2").

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[ evaluation test ]

[ measurement of pigment content CK and thickness DK in each colored resin layer LK ]

The pigment content CK and the thickness DK of each colored resin layer of each test-numbered laminate resin layer were measured by the following methods. Referring to fig. 15A, a design galvanized steel sheet is cut in a normal direction ND to prepare a cut section CS including the normal direction ND and the sheet width direction TD. Referring to fig. 15B, in the tangential section CS, a direction perpendicular to the normal direction ND (in this embodiment, the plate width direction TD) is defined as a tangential section width direction CD. The cut section CS is divided into 3 equal parts in the cut section width direction CD. In each of the 3-equally divided blocks X1 to X3, a sample SA including the laminated resin layer 30 is collected at the center position in the cross-sectional width direction CD. Each of the 3 samples SA contains at least the laminated resin layer 30 and the zinc-plated layer 10. The length in the tangential section width direction CD was set to 10mm, and the length in the direction perpendicular to the normal direction ND and the tangential section width direction CD was set to 10mm. For the cut sample SA, a sample capable of observing the laminated resin layer 30 and the galvanized layer 10 with a transmission electron microscope was prepared using a focused ion beam apparatus (FIB).

The surface (observation surface) of the sample SA including the normal direction ND and the tangential-section width direction CD was observed with a Scanning Electron Microscope (SEM) in a 2000-fold reflected electron image (BSE). In observation of a reflected electron image (BSE) using a Scanning Electron Microscope (SEM), the base steel sheet, the galvanized layer, and the laminated resin layer can be easily distinguished by contrast. In addition, since resin layers having different compositions are used for each colored resin layer in the laminated resin layers, the colored resin layers can be identified by their contrast.

After each colored resin layer was identified, the pigment content CK (volume%) in each colored resin layer and the average thickness DK of each colored resin layer were obtained by the following method.

In the observation by a transmission electron microscope, the total area A1 (. Mu.m) of the plurality of pigments in the colored resin layer on the observation surface was obtained ² ). Then, the area A0 (μm) of the colored resin layer on the observation surface was obtained ² ). Based on the obtained total area A1 and area A0, the area ratio (area%) of the pigment in the colored resin layer was obtained by the following formula.

Area ratio=a1/a0×100

The area ratio of the pigment was obtained in 3 samples, and the average of the obtained 3 area ratios was defined as the pigment content CK (vol%) of the colored resin layer.

In each sample SA, the thickness (μm) was measured at an arbitrary 1 point of each colored resin layer. The average of 3 thicknesses obtained in 3 samples SA was defined as the thickness DK (μm) of the colored resin layer. The pigment content CK (area%) and the thickness DK (μm) of each of the identified colored resin layers were obtained by the above method.

The color density index IK, which is an index of the color density of each colored resin layer, is obtained from the pigment content CK and the thickness DK of each colored resin layer by the following formula.

Color density index ik=ck×dk

Then, the total value of the color density index of each colored resin layer was obtained. The obtained total values are shown in the column "total color density index" of the column "laminated resin layer" in table 3A and table 3B.

[ measurement of thickness of laminate resin layer ]

The thickness of the laminated resin layer 30 is measured by the following method. Referring to fig. 15A and 15B, in the tangential section CS, a direction perpendicular to the normal direction ND is defined as a tangential section width direction CD (corresponding to the board width direction TD in the present embodiment). The cut section CS is divided into 3 equal parts in the cut section width direction CD. Samples SA containing the laminated resin layer 30 at the center position in the tangential cross-section width direction CD are collected in the 3-equally divided blocks X1 to X3, respectively. Each of the 3 samples SA contains at least the laminated resin layer 30 and the zinc-plated layer 10. The length in the cross section width direction CD was set to 10mm. In sample SA, the length in the direction perpendicular to the normal direction ND and the tangential-section width direction CD was set to 10mm. Gold vapor deposition was performed on the cut section CS of the cut sample SA. Then, the sample SA was sandwiched by the embedded resins, and ground to prepare a cut section CS as an observation surface, thereby preparing an observation sample. The observation surface of the observation sample was observed with a Scanning Electron Microscope (SEM) in a reflected electron image (BSE) of 2000 times. In observation of a reflected electron image (BSE) using a Scanning Electron Microscope (SEM), the base steel sheet 100, the galvanized layer 10, and the laminated resin layer 30 can be easily distinguished by contrast. In each sample SA, the thickness of the laminated resin layer 30 at 10 points was measured at a pitch of 100 μm in the tangential cross-sectional width direction CD. The average value of the thicknesses (total 30 points) measured in 3 samples SA was defined as the thickness (μm) of the laminated resin layer 30. The "total film thickness" of the column "laminated resin layer" in table 1 indicates the thickness (μm) of the laminated resin layer obtained by measurement.

[ most highly colored resin layer L ] _1ST And a 2 nd rich-colored resin layer L _2ND Is selected of (a)]

Among the colored resin layers, the colored resin layer having the largest color density index IK is defined as the "most intense colored resin layer L _1ST ", will be subsequent to the most-concentrated colored resin layer L _1ST The colored resin layer having the highest color density index IK, i.e., the colored resin layer having the color density index IK 2 higher than the first color index IK, is defined as the "2 nd rich colored resin layer L _2ND ". The most intense colored resin layer L _1ST Pigment content (% by area) of (C) is defined as _1ST ", the resin layer L is colored with the most intense color _1ST Thickness (μm) of (A) is defined as "D _1ST ". Coloring the 2 nd color resin layer L _2ND Pigment content (% by area) of (C) is defined as _2ND ", the 2 nd concentrated color coloring resin layer L _2ND Thickness (μm) of (A) is defined as "D _2ND ". The most intense colored resin layer L _1ST Pigment content C of (2) _1ST Thickness D _1ST The method comprises the steps of carrying out a first treatment on the surface of the Concentration 2Color-colored resin layer L _2ND Pigment content C of (2) _2ND Thickness (μm) D _2ND As shown in table 3A and table 3B. The "most intense colored resin layer L" in Table 3A and Table 3B _1ST The "lamination position" in the column indicates the most intense colored resin layer L _1ST What layer is. For example, in test number 12#, the most intense colored resin layer L is shown _1ST Layer 1. Similarly, the "2 nd concentrated color colored resin layer L" in Table 3A and Table 3B _2ND The "lamination position" of the "column" indicates the 2 nd rich colored resin layer L _2ND What layer is. For example, in test number 12#, the 2 nd rich colored resin layer L is shown _2ND Layer 2.

And, using the most dense colored resin layer L _1ST Pigment content C of (2) _1ST Thickness D _1ST The method comprises the steps of carrying out a first treatment on the surface of the 2 nd color-imparting resin layer L _2ND Pigment content C of (2) _2ND Thickness (μm) D _2ND The color density ratio RF was determined by the following formula.

Color density ratio rf= (C _1ST ×D _1ST )/(C _2ND ×D _2ND )

The obtained color density ratio RF is shown in the column "color density ratio RF" of the column "laminated resin layer" in table 3A and table 3B.

[ visual confirmation test of galvanized surface ]

Each sample was placed in an environment corresponding to solar light in the morning of a sunny day (illuminance about 65000 lux), and whether or not the surface energy of the base steel sheet 100 was visually confirmed was determined.

[ evaluation test for color unevenness ]

The color unevenness of the design galvanized steel sheet of each test number was evaluated by the following method. Referring to fig. 16, 81 measurement points (P1 to P81) were designated at 15mm intervals in an arbitrary measurement line segment OD1 of 1200mm running straight in the extending direction HD of the hairline 23 of each test number of the design galvanized steel sheet 1. At each of the measurement points P1 to P81, L is obtained ^* a ^* b ^* L in color system ^* Value, a ^* Value, b ^* Values. And, 2 adjacent measurement points Pi and pi+1 (i is 1Natural number of 80) Δl ^* Value Δa ^* Value, deltab ^* The value is obtained by the following equation.

ΔL ^* ＝L ^* i-L ^* i+1

Δa ^* ＝a ^* i-a ^* i+1

Δb ^* ＝b ^* i-b ^* i+1

And based on the obtained Δl ^* 、Δa ^* 、Δb ^* The color difference DeltaE between 2 adjacent measurement points was obtained by the following equation ^* 。

ΔE ^* ＝((ΔL ^* ) ² +(Δa ^* ) ² +(Δb ^* ) ² )

Based on the 80 ΔE obtained ^* Color unevenness was evaluated by the following criteria.

Score G: color difference delta E between adjacent 2 points ^* 90% or more and 2.0 or less of

Score P: color difference delta E between adjacent 2 points ^* More than 11% of which is more than 2.0

The results obtained are shown in the column "color unevenness" of the column "evaluation test" in table 3A and table 3B.

[ color fluctuation evaluation test ]

The color fluctuation of the design galvanized steel sheet of each test number was evaluated by the following method. Referring to fig. 17, in each test number of the designed galvanized steel sheet 1, 20 measurement positions S1 to S20 were designated at a pitch of 50000mm (50 m pitch) in the rolling direction RD. Further, at each of the measurement positions S1 to S20, the color difference ΔE of measurement points Q1 and Q2 having a distance of 1000mm in the direction (straight direction OD) straight from the extending direction HD of the hairline was obtained ^* 。

Based on the 20 color differences ΔE obtained ^* Color fluctuations were evaluated by the following criteria.

Score G: all of 20 points ΔE ^* ≤3.0

Score P: there are more than 1 ΔE in 20 points ^* >3.0 dot

The obtained results are shown in the column "color fluctuation" of the column "evaluation test" in table 1.

In the color unevenness evaluation test and the color fluctuation evaluation test, L at each of the measurement points P1 to P81, Q1, and Q2 ^* Value, a ^* Value and b ^* The value was measured using a colorimeter (trade name: CM-2600 d) manufactured by Konikoku Meida Co. In the measurement, L was obtained by using CIE standard illuminant D65 as illuminant, the viewing angle was set to 10 °, and color was expressed as CIELAB by SCE method ^* Value, a ^* Value, b ^* Values.

Here, CIE standard illuminant D65 is defined in JIS Z8720 (2000 "), a color measuring illuminant (standard light) and a standard illuminant", and ISO 10526 (2007) is defined in the same manner. CIE is a acronym for Co mmission Internationale de l' Eclairage, which stands for International Commission on illumination. CIE standard illuminant D65 is used when representing object colors under daylight illumination. The viewing angle of 10 ° is defined in JIS Z8723 (2009) "visual comparison method of surface color", and the same is defined in ISO/DIS 3668.

SCE method is also called specular reflection light removal method, and means a method of measuring color by removing specular reflection light. The SCE method is defined in JIS Z8722 (2009). In the SCE method, since specular reflection light is removed and measurement is performed, a color (so-called visual color) similar to a color actually seen by the human eye is measured.

CIELAB indicates a uniform color space prescribed in JIS Z8781 (2013) recommended in 1976 for measuring color difference caused by difference in perception and device. L for 3 coordinates of CIELAB ^* Value, a ^* Value, b ^* The value represents. L (L) ^* The value represents brightness and is represented by 0 to 100. L (L) ^* The value of 0 represents black, L ^* A value of 100 indicates a diffuse reflection of white. a, a ^* The value represents the color between red and green. a, a ^* The value is a negative number, and represents a greenish color, and is a positive number, and represents a reddish color. b ^* The values represent the colors between yellow and blueColor. b ^* If negative, a bluish color is indicated, and if positive, a yellowish color is indicated.

[ evaluation results ]

Referring to tables 3A and 3B, one or both of "color unevenness" and "color fluctuation" of test numbers (no # added number) without resin lamination were evaluated as "P", whereas all of test numbers (no # added number) with resin lamination were evaluated as "G" in both "color unevenness" and "color fluctuation".

Description of symbols

1,1' plated steel sheet

10 10' Zinc coating

10S,10S' texture

11 11' colored resin layer

30. Laminated resin layer

31 31' resin

32 32' colorant

100 100' base metal steel plate

Claims

1. A plated steel sheet is provided with:

a base metal steel plate having base metal textures on the surface,

the zinc-plated layer has a plating texture on its surface,

the colored resin layer contains a colorant,

when the rolling direction of the base steel sheet is defined as the 1 st direction and the direction perpendicular to the 1 st direction on the surface of the plated steel sheet is defined as the 2 nd direction, the plated steel sheet satisfies the following (a) to (F):

(A) Measuring a roughness profile in a range of 1000 [ mu ] m in length in the 2 nd direction of the plating texture, wherein when a lowest position in each of the recesses in the roughness profile obtained by the measurement is defined as a recess bottom point, among a plurality of recess bottom points of the roughness profile, 10 recess bottom points are designated in order from the lowest recess bottom point, three-dimensional average roughness Sa of a minute region of 1 [ mu ] m×1 [ mu ] m centered on the designated recess bottom point is measured, and when an arithmetic average of the 10 three-dimensional average roughness Sa obtained by the measurement is defined as recess bottom three-dimensional average roughness Sas, the recess bottom three-dimensional average roughness Sas is greater than 200nm and not more than 2000nm,

(B) In the range of 100 μm in length in the 2 nd direction, the minimum thickness of the colored resin layer is defined as Dkmin, the content of the colorant in the colored resin layer is defined as CK area%, when F1 is defined by the formula (1), the F1 is 15.0 or less, the unit of the minimum thickness is μm,

F1＝DKmin×CK (1)

(C) In the range of the length of 100 μm in the 2 nd direction, the maximum thickness of the colored resin layer is defined as Dkmax, and when F2 is defined by the formula (2), the F2 is greater than 1.0, the unit of the maximum thickness is μm,

F2＝(DKmax-DKmin)×CK (2)，

(D) Measuring a roughness profile in a range of 1000 [ mu ] m in length in the 2 nd direction of the plating texture, and when the highest position of each of the convex parts in the roughness profile obtained by the measurement is defined as a convex part vertex, among a plurality of convex part vertices of the roughness profile, 10 convex part vertices are designated in order from highest convex part vertex to lowest, three-dimensional average roughness Sa of a minute region of 1 [ mu ] m×1 [ mu ] m centering on the designated convex part vertex is measured, and when an arithmetic average of the 10 three-dimensional average roughness Sa obtained by the measurement is defined as a convex part top three-dimensional average roughness Sah, the convex part top three-dimensional average roughness Sah is larger than 5nm and 200nm or less,

F3＝Ra(CC)/Ra(CL) (3)，

2. The plated steel sheet according to claim 1, wherein,

a plurality of the convex portions and a plurality of the concave portions extend in the 1 st direction,

the plurality of convex portions and the plurality of concave portions are arranged in the 2 nd direction.

3. The plated steel sheet according to claim 2, wherein,

the base material texture is hairline,

the plating texture is hairline.

4. The plated steel sheet according to any one of claim 1 to 3, wherein,

brightness L when the plated steel sheet is observed from the side of the colored resin layer ^* The (SCI) is 45 or less.

5. The plated steel sheet according to any one of claim 1 to 3, wherein,

f1 is 13.5 or less.

6. The plated steel sheet according to any one of claim 1 to 3, wherein,

f2 is greater than 2.0.

7. The plated steel sheet according to claim 1, wherein,

and F3 is more than 1.15.

8. The plated steel sheet according to any one of claim 1 to 3, wherein,

the exposure rate of the base steel plate of the galvanized layer is less than 5%.

9. The plated steel sheet according to claim 1, wherein,

a plurality of the convex portions are formed by grinding the surface of the zinc plating layer,

a plurality of the recesses are not ground.

10. A plated steel sheet is provided with:

a base steel plate,

A zinc-plated layer formed on the surface of the base steel sheet, and

a colored resin layer formed on the zinc plating layer,

the zinc coating layer has a texture extending in one direction on its surface,

the colored resin layer contains a colorant,

the plated steel sheet satisfies the following (A ') to (E'):

(B ') in a range of a length of 100 [ mu ] m in a direction perpendicular to an extending direction of the texture, a minimum thickness of the colored resin layer is defined as Dkmin', and when a content of the colorant in the colored resin layer is defined as CK 'area%, the formula (1') is satisfied, the unit of the minimum thickness is [ mu ] m,

DKmin’×CK’≤15.0(1’)；

(C ') when the maximum thickness of the colored resin layer is defined as DKmax' in a range of 100 μm in length in a direction perpendicular to the extending direction of the texture, the unit of the maximum thickness is μm,

(DKmax’-DKmin’)×CK’>1.0(2’)，

Ra(CC)’≥Ra(CL)’×1.10(3’)；

11. The plated steel sheet according to claim 10, wherein,

the texture is hairline.

12. The plated steel sheet according to claim 10 or claim 11, wherein,

13. The plated steel sheet according to any one of claims 1 to 3 and 10 to 11,

the colored resin layer is a laminated resin layer,

the laminated resin layer comprises a plurality of colored resin layers laminated in the normal direction of the surface of the base steel plate,

in the plurality of colored resin layers, the sum of the product of the content (area%) of the colorant in the colored resin layer and the thickness (μm) of the colored resin layer is 15.0 area%. Mu.m or less,

among the plurality of colored resin layers, a colored resin layer having a largest product of a content (area%) of the colorant in the colored resin layer and a thickness (μm) of the colored resin layer is defined as a most intense colored resin layer, and a coloring having a 2 nd largest product of the content of the colorant in the colored resin layer and the thickness of the colored resin layer is defined as a coloring having a 2 nd largest product of the content of the colorant in the colored resin layer and the thickness of the colored resin layerWhen the resin layer is defined as the 2 nd rich colored resin layer, the content C of the colorant of the most rich colored resin layer _1ST (area%), thickness D of the most dense colored resin layer _1ST (μm), the content C of the colorant of the 2 nd concentrated color colored resin layer _2ND (area%) and the thickness D of the 2 nd dense color colored resin layer _2ND (μm) satisfies the formula (4),

1.00<(C _1ST ×D _1ST )/(C _2ND ×D _2ND )≤4.00 (4)。

14. The plated steel sheet according to claim 13, wherein,

the thickness of the laminated resin layer is 10.0 μm or less.

15. The plated steel sheet according to claim 13, wherein,

the laminated resin layer further comprises 1 or more transparent resin layers containing no colorant,

the laminated resin layer is formed by laminating the plurality of colored resin layers and the 1 or more transparent resin layers.