Chemical conversion coating solution, method for coloring metal element, metal element, and slide fastener

Abstract

A chemical conversion coating solution containing selenium dioxide and sodium persulfate is provided, which is advantageous for forming a colored coating having excellent corrosion resistance on the surface of a metal element of a slide fastener. A chemical conversion coating solution for a metal element of a slide fastener contains SeO2, CuCl2, H2SO4, and Na2S2O8.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present invention claims the benefit of priority to Japanese Patent Application No. 2025-10082 filed on Jan. 23, 2025 with the Japanese Patent Office, the entire contents of which are incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention is related to a chemical conversion coating solution for a metal element of a slide fastener. The present invention is related to a method for coloring a metal element of a slide fastener. The present invention is related to a metal element of a slide fastener. Further, the present invention is related to a slide fastener including a metal element.BACKGROUND OF THE INVENTION

[0003] Some slide fasteners have element rows made of metal, and such slide fasteners are generally collectively referred to as “metal fasteners.” Slide fasteners are required to have attractive appearances depending on the applications in which they are used, and it has become necessary to provide metal elements in a variety of colors. Known methods for changing the color tone of metal elements include electrochemical surface treatments such as anodizing, electrolytic plating, electroless plating, chemical conversion coating, and electrodeposition coating.

[0004] In recent years, as the color tones required in the market have become more diverse, a method has been known in which metal fastener parts are colored by chemical conversion coating using a chemical solution containing selenium dioxide and sodium persulfate (Patent Literature 1).PRIOR ARTPatent Literature

[0005] [Patent Literature 1] CN 108707882 BSUMMARY OF THE INVENTION

[0006] However, the prior art chemical solution containing selenium dioxide (SeO2) and sodium persulfate (Na2S2O8) do not provide sufficient corrosion resistance to the colored coatings obtained, and there is still room for improvement. In view of the above circumstances, an object of one embodiment of the present invention is to provide a chemical conversion coating solution containing selenium dioxide and sodium persulfate that is advantageous for forming a colored coating having excellent corrosion resistance on the surface of a metal element of a slide fastener. An object of another embodiment of the present invention is to provide a method for coloring a metal element having a colored coating with excellent corrosion resistance using such a chemical conversion coating solution. An object of yet another embodiment of the present invention is to provide a metal element that is colored using such a chemical conversion coating solution and has a colored coating that is excellent in corrosion resistance. An object of yet another embodiment of the present invention is to provide a slide fastener comprising such a metal element.

[0007] As a result of extensive research to solve the above problems, the present inventors have discovered that the corrosion resistance of a colored coating can be improved by adding copper (II) chloride (CuCl2) and sulfuric acid (H2SO4) to selenium dioxide (SeO2) and sodium persulfate (Na2S2O8). The present invention has been completed based on the above findings, and is exemplified as below.[Aspect 1]

[0008] A chemical conversion coating solution for a metal element of a slide fastener, the chemical conversion coating solution comprising SeO2, CuCl2, H2SO4, and Na2S2O8.[Aspect 2]

[0009] A chemical conversion coating solution for a metal element of a slide fastener, the chemical conversion coating solution comprising 1.0 to 5.0 g / L of SeO2, 0.08 to 0.78 g / L of CuCl2, 1 to 11 g / L of H2SO4, and 1.0 to 10.0 g / L of Na2S2O8.[Aspect 3]

[0010] A chemical conversion coating solution for a metal element of a slide fastener, the chemical conversion coating solution comprising 2.0 to 4.0 g / L of SeO2, 0.31 to 0.63 g / L of CuCl2, 8 to 11 g / L of H2SO4, and 2.0 to 8.0 g / L of Na2S2O8.[Aspect 4]

[0011] A method for coloring a metal element of a slide fastener, comprising:

[0012] step 1 of degreasing the metal element of the slide fastener;

[0013] step 2 of subjecting the metal element of the slide fastener after the step 1 to a chemical conversion coating using the chemical conversion coating solution according to any one of aspects 1 to 3; and

[0014] step 3 of applying electroless tin plating to the metal element of the slide fastener after the step 2.[Aspect 5]

[0015] The method for coloring the metal element of the slide fastener according to aspect 4, wherein the step 2 comprises immersing the metal element of the slide fastener after the step 1 in the chemical conversion coating solution at 20 to 50° C. for 20 to 200 seconds.[Aspect 6]

[0016] The method for coloring the metal element of the slide fastener according to aspect 4 or 5, further comprising a step 4 of subjecting the metal element of the slide fastener after the step 3 to a rust prevention treatment.[Aspect 7]

[0017] The method for coloring the metal element of the slide fastener according to aspect 6, further comprising step 5 of lacquering the metal element of the slide fastener after the step 4.[Aspect 8]

[0018] The method for coloring the metal element of the slide fastener according to any one of aspects 4 to 7, further comprising step 6 of chemically polishing the metal element of the slide fastener before the step 1.[Aspect 9]

[0019] The method for coloring the metal element of the slide fastener according to any one of aspects 4 to 8, wherein the metal element of the slide fastener is made of a copper alloy as a base material.[Aspect 10]

[0020] A metal element of a slide fastener with a colored coating, satisfying the following Condition 1 when a line analysis using energy dispersive X-ray spectroscopy is performed from an outermost surface of the metal element in a depth direction,

[0021] Condition 1: for a metallic element with a highest concentration that constitutes a base material of the metal element of the slide fastener, assuming an average intensity in a depth range of 2,000 to 3,000 μm from the outermost surface is IM, a depth position the closest to the outermost surface where an intensity of the metallic element is 0.4IM is D1, and a depth position from the outermost surface where the intensity of the metal element is 0.7×IM is D2, then Se, O, Sn, Cu, and Cl are detected in a depth range from D1 to D2.[Aspect 11]

[0022] The metal element of the slide fastener according to aspect 10, further satisfying the following Condition 2,

[0023] Condition 2: C is detected continuously in the depth range from D1 to D2.[Aspect 12]

[0024] The metal element of the slide fastener according to aspect 10 or 11, further satisfying the following Condition 3,

[0025] Condition 3: assuming an average intensity of C in the depth range from D1 to D2 is ICl and an average intensity of Se in the same depth range is ISe, then 0.2×Ise≤ICl≤0.6×ISe is satisfied.[Aspect 13]

[0026] The metal element of a slide fastener according to any one of aspects 10 to 12, further satisfying the following Condition 4,

[0027] Condition 4: assuming a maximum intensity of Sn is ISn and a depth position the farthest from the outermost surface where an intensity of Sn is 0.5×ISn is D3, then D3 is located deeper than D2.[Aspect 14]

[0028] The metal element of the slide fastener according to any one of aspects 10 to 13, further satisfying the following Condition 5,Condition 5:an average intensity of Se in the depth range from D1 to D2 is 0.1×IM to 0.7×IM,

[0030] an average intensity of O in the depth range from D1 to D2 is 0.1×IM to 0.3×IM,

[0031] an average intensity of Sn in the depth range from D1 to D2 is 0.1×IM to 0.7×IM,

[0032] an average intensity of Cu in the depth range from D1 to D2 is 0.1×IM to 0.8×IM, and

[0033] an average intensity of Cl in the depth range from D1 to D2 is 0.1×IM to 0.5×IM.[Aspect 15]

[0034] The metal element of the slide fastener according to any one of aspects 10 to 14, wherein a distance in the depth direction from the outermost surface to D1 is 0.1 to 0.5 μm.[Aspect 16]

[0035] The metal element of the slide fastener according to any one of aspects 10 to 15, wherein a distance in the depth direction between D1 and D2 is 0.3 to 1.5 μm.[Aspect 17]

[0036] The metal element of the slide fastener according to any one of aspects 10 to 16, wherein the metal element with the highest concentration that constitutes the base material of the metal element of the slide fastener is Cu.[Aspect 18]

[0037] The metal element of the slide fastener according to any one of aspects 10 to 17, wherein the base material of the metal element of the slide fastener is a copper alloy containing zinc.[Aspect 19]

[0038] A slide fastener comprising a row of the metal elements according to any one of aspects 10 to 18.

[0039] According to one embodiment of the present invention, there is provided a chemical conversion coating solution comprising selenium dioxide and sodium persulfate, which is advantageous for forming a colored coating having excellent corrosion resistance on the surface of a metal element of a slide fastener. By using this chemical conversion coating solution, it is possible to provide a metal element having a colored coating with excellent corrosion resistance. Such metal elements have a long service life, which contributes to extending the life of the slide fastener and is therefore thought to be useful in conserving resources by reducing waste.BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG. 1 is a schematic perspective view of a metal element.

[0041] FIG. 2 is a schematic side view of a metal element.

[0042] FIG. 3 is a schematic front view of a metal fastener.

[0043] FIG. 4 is a diagram illustrating a method for attaching a row of metal elements to the core of the fastener tape.

[0044] FIG. 5 is an example of the results of line analysis by SEM-EDX on the metal element according to Example 1.

[0045] FIG. 6 is an example of the results of line analysis by SEM-EDX on the metal element according to Example 2.DETAILED DESCRIPTION OF THE INVENTION(1. Chemical Conversion Coating Solution)

[0046] A chemical conversion coating solution for a metal element of a slide fastener according to one embodiment of the present invention comprises SeO2, CuCl2, H2SO4, and Na2S2O8 in water. These may be ionized in water and exist as ions. The conversion coating solution is typically provided as an aqueous solution. Although it is not intended that the present invention be limited by any theory, it is believed the reason is that the inclusion of copper chloride (II) and sulfuric acid (H2SO4) in addition to selenium dioxide (SeO2) and sodium persulfate (Na2S2O8) in the chemical conversion coating solution not only improves the corrosion resistance of chemical conversion coating itself obtained by the chemical conversion coating, but also makes it easier for Sn to penetrate through the chemical conversion coating into the base material when Sn plating is performed after the chemical conversion coating, and a highly uniform colored coating is obtained in which the chemical conversion coating and the plating film are integrated. Copper (II) chloride can be used in the form of anhydrous CuCl2 or dihydrate CuCl2·2H2O. Either of the two may be used alone, and the two may be used in combination.

[0047] A chemical conversion coating solution for a metal element of a slide fastener according to a preferred embodiment of the present invention comprises 1.0 to 5.0 g / L of SeO2, 0.08 to 0.78 g / L of CuCl2, 1 to 11 g / L of H2SO4, and 1.0 to 10.0 g / L of Na2S2O8. In addition, the above concentration range of copper(II) chloride refers to the concentration range converted into the mass of anhydrous copper(II) chloride when a dihydrate is used as copper(II) chloride.

[0048] A chemical conversion coating solution for a metal element of a slide fastener according to a more preferred embodiment of the present invention comprises 2.0 to 4.0 g / L of SeO2, 0.31 to 0.63 g / L of CuCl2, 8 to 11 g / L of H2SO4, and 2.0 to 8.0 g / L of Na2S2O8.(2. Method for Coloring a Metal Element)

[0049] A method for coloring a metal element of a slide fastener according to one embodiment of the present invention comprises:

[0050] step 1 of degreasing the metal element of the slide fastener;

[0051] step 2 of subjecting the metal element of the slide fastener after the step 1 to a chemical conversion coating using the chemical conversion coating solution according to any one of chemical conversion coating solutions described above; and

[0052] step 3 of applying electroless tin plating to the metal element of the slide fastener after the step 2.

[0053] In the step 1, the metal element of the slide fastener is degreased. Degreasing before chemical conversion coating ensures stable and uniform coloring. As the method for degreasing, any known method for metal elements can be used, and mention can be made to immersing the metal element in an organic solvent (solvent cleaning), immersing the metal element in an alkaline aqueous solution (alkaline immersion degreasing), or immersing the metal element in an alkaline aqueous solution and electrolyzing it (alkaline electrolytic degreasing), and the like. The temperature of the degreasing solution can be set to, for example, 30 to 60° C., preferably 40 to 60° C., and more preferably 55 to 60° C., in consideration of the balance between the degreasing effect and the prevention of discoloration. The degreasing time can be set to, for example, 30 to 180 seconds, preferably 80 to 150 seconds, and more preferably 90 to 120 seconds, taking into account the balance between the degreasing effect and productivity. After the degreasing treatment, it is preferable to wash the metal element with water.

[0054] In the step 2, the metal element of the slide fastener after the step 1 is subjected to a chemical conversion coating using the chemical conversion coating solution according to any one of the above-described embodiments. The chemical conversion coating can be carried out by bringing the metal element into contact with a chemical conversion coating solution. Methods for bringing the metal element into contact with the chemical conversion coating solution include, for example, immersion, spraying, and pouring. In a preferred embodiment, in the step 2, the metal element of the slide fastener after step 1 is subjected to chemical conversion coating by immersing it in the chemical conversion coating solution according to any one of the above-described embodiments. In this case, the temperature of the chemical conversion coating solution is preferably 20 to 50° C., more preferably 30 to 40° C., for reasons of reaction stability and safety. In addition, the color tone can be changed by changing the immersion time. When the immersion method is employed, the time for immersing the metal element in the chemical conversion coating solution may be appropriately set depending on the desired color tone, but is preferably 20 to 200 seconds, and more preferably 30 to 150 seconds, for example. After the chemical conversion coating, the metal element is preferably washed with water.

[0055] In the step 3, the metal element of the slide fastener after the step 2 is subjected to electroless tin plating. After the chemical conversion coating, the color becomes darker, but by applying electroless tin plating, a silvery gunmetal color can easily be obtained. Electroless tin plating can be carried out by employing a known method, for example, a method of electroless tin plating in which a metal element is immersed in a plating solution is suitable. A plating solution used in electroless tin plating usually contains a tin salt, an acid that dissolves the tin salt, and a complexing agent as basic components. Acids that dissolve the tin salt include organic sulfonic acids, mineral acids, hydrofluoroboric acid, and polyoxycarboxylic acids. The Sn concentration in the plating solution can be, for example, 0.5 to 2.0 g / L, and preferably 0.8 to 1.5 g / L. The temperature of the plating solution is preferably 20 to 50° C., and more preferably 30 to 40° C. The time for immersing the metal element in the plating solution may be appropriately set depending on the desired color tone, but is preferably 15 to 90 seconds, more preferably 30 to 60 seconds, for example. After electroless tin plating, it is preferable to rinse the metal element of the slide fastener with water.

[0056] After the step 3, the metal element of the slide fastener may be further subjected to the step 4 of rust prevention treatment. Examples of the rust inhibitor used in the rust prevention treatment include nitrites, nitrates, chromates, carboxylates, molybdates, pyrazoles, triazoles, tetrazoles, and thiazoles. When the base material of the metal element is a copper alloy, an azole-based rust inhibitor containing an azole compound such as benzotriazole (BTA), tolyltriazole (TTA), or mercaptobenzothiazole (MBT) is suitable. The rust inhibitor can be provided as an aqueous solution, for example, by dissolving it in water. Therefore, the preferred rust prevention method is to immerse the metal element in an aqueous solution of a rust inhibitor. The temperature of the aqueous solution of the rust inhibitor is preferably 10 to 40° C. more preferably 15 to 35° C. The immersion time of the metal element in the aqueous rust inhibitor solution is, for example, preferably 1 to 30 seconds, and more preferably 1 to 10 seconds. After the rust prevention treatment, it is preferable to dry the metal element of the slide fastener. As a method for drying the metal element, for example, it may be dried in a hot air dryer at 80 to 130° C., preferably 90 to 120° C., for 60 to 300 seconds, preferably 100 to 200 seconds.

[0057] After the step 4, the metal element of the slide fastener may be further subjected to step 5 of lacquering (particularly clear lacquering) to prevent discoloration and migration. Examples of paints used for lacquering include paints (polyurethane resin paints) that combine a resin (polyol) with multiple hydroxyl groups as a main component with polyisocyanate as a curing agent, and among these, acrylic urethane resin paints that use acrylic polyol as the main component are preferred. A suitable method for lacquering is, for example, roll coating. Lacquering can be carried out in air at a temperature of, for example, 10 to 50° C., and is preferably carried out in air at a temperature of 20 to 35° C. After lacquering, it is preferable to dry the metal element of the slide fastener. The metal element may be dried, for example, in a hot air dryer at 100 to 140° C., preferably 110 to 130° C., for 300 to 700 seconds, preferably 360 to 500 seconds.

[0058] In addition, it is preferable that the metal element of the slide fastener be subjected to step 6 of chemical polishing as a pretreatment before the step 1 is carried out. Chemical polishing can be performed, for example, by immersing the metal element in a chemical polishing solution. A typical chemical polishing solution is an acidic liquid obtained by adding an acid such as sulfuric acid or fluoride acid to an oxidizing agent such as hydrogen peroxide. The chemical polishing solution may further contain a stabilizer. A suitable method for chemical polishing is, for example, an immersion method. The temperature of the chemical polishing solution is preferably 25 to 60° C., and more preferably 40 to 45° C. When the immersion method is employed, the immersion time of the metal element in the chemical polishing solution is preferably, for example, 30 to 300 seconds, and more preferably 120 to 140 seconds.

[0059] Before chemical polishing, degreasing and pickling may be carried out in this order, or after chemical polishing, pickling, neutralization, and drying may be carried out in this order, or water washing may be carried out between each step.(3. Metal Element)

[0060] FIG. 1 shows a schematic perspective view of a metal element 3 of a slide fastener. FIG. 2 shows a schematic side view of the metal element 3 of the slide fastener. The metal element 3 includes a pair of legs 10 and a head 9 that connects the pair of legs 10 and has a convex portion 9a and a concave portion 9b for engagement.

[0061] There is no particular limitation on the material constituting the base material of the metal element 3, and copper (pure copper), copper alloys (for example, copper alloys containing zinc such as red brass, brass, and nickel silver (Cu—Zn alloys)), aluminum alloys (Al—Cu alloys, Al—Mn alloys, Al—Si alloys, Al—Mg alloys, Al—Mg—Si alloys, Al—Zn—Mg alloys, and Al—Zn—Mg—Cu alloys, and the like), zinc, zinc alloys, iron, and iron alloys (stainless steel and the like), and the like can be used. Among these, copper alloys are preferred for reasons of workability, and copper alloys containing zinc (Cu—Zn alloys) such as red brass, brass, and nickel silver are more preferred. Therefore, in a preferred embodiment, the metal element with the highest concentration that constitutes the base material of the metal element 3 is Cu.

[0062] The metal element 3 can be manufactured, for example, by cutting a deformed wire having an approximately Y-shaped cross section that has been produced through heat treatment and cold rolling into specified dimensions, and then press-forming the cut wire to form a convex portion 9a and a concave portion 9b for engagement in the head 9. Next, by applying the above-described coloring method to the metal element 3, it is possible to manufacture the metal element 3 having a colored coating. The surface of the metal element 3 may be subjected to a surface treatment other than the above-mentioned coloring method, such as smoothing treatment and / or gloss polishing, at an appropriate timing before or after carrying out the above-mentioned coloring method.

[0063] According to one embodiment of the present invention, there is provided a metal element of a slide fastener with a colored coating, which, when a line analysis using energy dispersive X-ray spectroscopy (SEM-EDX) is performed in the depth direction from the outermost surface of the metal element, satisfies the following Condition 1; in a preferred embodiment, a metal element of a slide fastener is provided that further satisfies one or more of the following Conditions 2 to 5; in a more preferred embodiment, a metal element of a slide fastener is provided that further satisfies two or more of the following Conditions 2 to 5; in an even more preferred embodiment, a metal element of a slide fastener is provided that further satisfies three or more of the following Conditions 2 to 5; and in a most preferred embodiment, a metal element of a slide fastener is provided that further satisfies all of the following Conditions 2 to 5.

[0064] The outermost surface of the metal element means the outermost surface of a coating formed by carrying out various surface treatments such as chemical conversion coating, Sn plating, rust prevention treatment, lacquer coating, and the like.

[0065] Condition 1: for the metallic element with the highest concentration that constitutes the base material of the metal element of the slide fastener, assuming the average intensity in a depth range of 2,000 to 3,000 μm from the outermost surface is IM, a depth position the closest to the outermost surface where an intensity of the metallic element is 0.4IM is D1, and a depth position the closest to the outermost surface where the intensity of the metallic element is 0.7×IM is D2, then Se, O, Sn, Cu, and Cl are detected in a depth range from D1 to D2.

[0066] Condition 2: C is detected continuously in the depth range from D1 to D2.

[0067] Condition 3: assuming the average intensity of Cl (average Cl intensity) in the depth range from D1 to D2 is li and an average intensity of Se (average Se intensity) in the same depth range is ISe, then 0.2×Ise≤ICl≤0.6×ISe is satisfied, preferably 0.3×ISe≤ICl≤0.5×ISe is satisfied.

[0068] Condition 4: assuming the maximum intensity of Sn is ISn and a depth position the farthest from the outermost surface where an intensity of Sn is 0.5×ISn is D3, then D3 is located deeper than D2.

[0069] Condition 5:

[0070] the average intensity of Se in the depth range from D1 to D2 is 0.1×IM to 0.7×IM, preferably 0.2×IM to 0.6×IM,

[0071] the average intensity of O in the depth range from D1 to D2 is 0.1×IM to 0.3×IM, preferably 0.1×IM to 0.2×IM,

[0072] the average intensity of Sn in the depth range from D1 to D2 is 0.1×IM to 0.7×IM, preferably 0.2×IM to 0.5×IM,

[0073] the average intensity of Cu in the depth range from D1 to D2 is 0.1×IM to 0.8×IM, preferably 0.1×IM to 0.3×IM, and

[0074] the average intensity of C in the depth range from D1 to D2 is 0.1×IM to 0.5×IM, preferably 0.2×IM to 0.3×IM.

[0075] The distance X1 in the depth direction from the outermost surface of the metal element to D1 is, for example, 0.1 to 0.5 μm, and preferably 0.2 to 0.5 μm.

[0076] The distance X2 between D1 and D2 in the depth direction is, for example, 0.3 to 1.5 μm, and preferably 0.5 to 1.0 μm.

[0077] The line analysis by SEM-EDX is carried out using the following equipment and measurement conditions.

[0078] Analytical equipment: JEOL Ltd. JSM-IT700HR scanning electron microscope or an analytical equipment with equivalent performance

[0079] Observation model: Secondary electron image

[0080] Measurement voltage: 15 kV

[0081] Measurement current: 65 mA

[0082] Vacuum level: 9.99E-07 Pa

[0083] Sample preparation: A cross section perpendicular to the surface of the base material is cut out from a location near the center of the length from the base to the tip of the leg of the metal element of the slide fastener to be measured, exposing the cross section of the colored coating and base material (see FIG. 1). Next, a vicinity of the surface of the outer side surface of the legs indicated by the arrow in FIG. 1 in the cross section is subjected to elemental analysis at a magnification of 20,000 times, and near the center of the SEM image in the direction perpendicular to the thickness direction of the coating (near the center between the right and left), a line analysis is performed on the energy intensity of characteristic X-rays for each element (K-line for C, O, Cl, Cu, and Zn, and L-line for Se and Sn) in the depth direction (direction perpendicular to the outermost surface) up to a distance of 5 μm from the outermost surface. The line analysis is carried out at two points on the cross section, and the average value is taken as the measured value.(4. Metal Fastener)

[0084] Metal fasteners can be attached to a variety of items and function particularly as closures. There are no particular limitations on the types of articles to which metal fasteners can be attached, but examples include daily necessities such as clothing, bags, shoes, and miscellaneous goods, as well as industrial items such as water tanks, fishing nets, and space suits.

[0085] FIG. 3 shows a schematic front view of an exemplary metal fastener. As shown in FIG. 3, the metal fastener comprises a pair of fastener tapes 1 each having a row of metal elements 3 attached to the inner edge thereof at predetermined intervals in the longitudinal direction L of the fastener tape 1. A state in which a row of metal elements 3 is attached to the side edge of one fastener tape 1 is called a stringer, and a state in which the rows of opposing metal elements 3 of a pair of stringers are in an interlocking state is called a fastener chain. A fastener comprising a fastener chain and a slider inserted between rows of metal elements 3 of the fastener chain is called a slide fastener. A direction parallel to the main surface 13 of the fastener tape 1 and perpendicular to the longitudinal direction L of the fastener tape 1 is called a width direction W of the fastener tape 1. Further, a direction perpendicular to the main surface 13 of the fastener tape 1 is referred to as the thickness direction T of the fastener tape 1.

[0086] The fastener tape 1 comprises a main body 11 and a core 12 formed along the inner edge thereof. Each metal element 3 constituting the row of metal elements 3 is attached by being crimped to a core portion 12 formed on the inner edge of the fastener tape 1. In addition, the metal fastener may also include an upper stop 4 and a lower stop 5 that are crimped and fixed to the core 12 of the fastener tape 1 at the upper and lower ends of the row of metal elements 3, and a slider 6 that is inserted between a pair of opposing rows of metal elements 3 and can slide freely in the vertical direction to engage and separate the pair of metal elements 3. The lower stop 5 may be a separable end stop having an insert pin, a box pin, and a box body, and may be configured so that the pair of fastener chains can be separated by opening the slider 6. Other embodiments not shown are also possible.

[0087] FIG. 4 is a diagram illustrating a method for attaching a row of metal elements 3 to the core portion 12 of the fastener tape 1. The metal element 3 is attached by crimping both legs 10 to a core portion 12 formed on the side edges of the fastener tape 1 along the longitudinal direction of the fastener tape 1. A number of metal elements 3 are attached to the side edges of the fastener tape 1 at predetermined intervals in the longitudinal direction of the fastener tape 1, thereby fabricating a stringer. Next, the rows of opposing metal elements 3 of a pair of stringers are interlocked to fabricate a fastener chain.

[0088] As the fastener tape 1, any fiber tape such as woven fabric tape, knitted fabric tape, or nonwoven fabric tape that has been used in conventional slide fasteners can be used without any particular restrictions. As the fiber material, polyester, nylon, polypropylene, acrylic, and the like, which have been used in conventional slide fasteners, can be used without any particular restrictions.EXAMPLES

[0089] Hereinafter, the Examples of the present invention are provided for a better understanding of the present invention and its advantages, but are not intended to limit the present invention.Example 1(1. Fabrication of the Fastener Chain)

[0090] After undergoing heat treatment, cold rolling, cutting, and press forming, a large number of metal elements were prepared that had the structure shown in FIGS. 1 and 2, were sized to correspond to the chain width of M class (JIS S3015: 2019), and had a base material made of copper-zinc alloy. The rows of the metal elements were fixed to the side edges of a fastener tape by crimping to form stringers, and the opposing rows of the metal elements of a pair of stringers were then meshed together to form a fastener chain.(2. Pretreatment)

[0091] The metal elements of the fabricated fastener chain were subjected to chemical polishing as a pretreatment. Chemical polishing was carried out by immersing the fastener chain in a chemical polishing solution containing hydrogen peroxide and sulfuric acid at 45° C. for 120 seconds. Before chemical polishing, the metal elements of the fastener chain were subjected to alkali immersion degreasing, water washing, acid pickling (dilute sulfuric acid), and water washing in this order. After the chemical polishing, the metal elements of the fastener chain were subjected to water washing, acid pickling (dilute sulfuric acid), water washing, neutralization with NaOH, water washing, and drying in this order.(3. Coloring Treatment)

[0092] The pretreated fastener chain was immersed in an alkaline aqueous solution at 60° C. for 120 seconds to perform alkali immersion degreasing on the metal element, followed by rinsing with water.

[0093] Next, the fastener chain after the degreasing treatment was immersed in a chemical conversion coating solution under the temperature and time conditions shown in Table 1, the chemical conversion coating solution prepared by adding the components shown in Table 1 to water at the concentrations shown in Table 1, thereby performing a chemical conversion coating on the metal elements. Thereafter, washing with water was carried out.

[0094] Next, the fastener chain after the chemical conversion coating was immersed in an acid plating bath (Sn concentration: 1.0 g / L) at 35° C. for 30 seconds to perform electroless tin plating on the metal element. Thereafter, the fastener chain was washed with water.

[0095] Next, the fastener chain after electroless tin plating was immersed in an aqueous solution of an azole-based rust inhibitor at room temperature for one second, thereby performing rust prevention treatment on the metal elements. Thereafter, drying was carried out in a hot air dryer at 120° C. for 120 seconds.

[0096] Next, the metal elements after the rust prevention treatment were subjected to a clear lacquer coating by roll coating in the air at room temperature using an acrylic urethane resin paint. Thereafter, drying was carried out in a hot air dryer at 120° C. for 120 seconds.

[0097] As a result, a fastener chain provided with the metal elements according to Example 1 was obtained.Example 2

[0098] The same fastener chain as in Example 1 was prepared. Next, pretreatment and coloring treatment were carried out on the metal element under the same conditions as in Example 1, except that the conditions for chemical conversion coating were changed to those shown in Table 1. As a result, a fastener chain provided with the metal elements according to Example 2 was obtained.Comparative Example 1

[0099] The same fastener chain as in Example 1 was prepared, and the same pretreatment as in Example 1 was carried out. Next, the pretreated fastener chain was immersed in an alkaline aqueous solution at 60° C. for 120 seconds, thereby performing alkaline immersion degreasing on the metal element. Thereafter, washing with water was carried out.

[0100] Next, the fastener chain after the degreasing treatment was immersed in a chemical conversion coating solution under the temperature and time conditions shown in Table 1, which was prepared by adding the components shown in Table 1 to water at the concentrations shown in Table 1, thereby performing a chemical conversion coating on the metal element. Thereafter, washing with water was carried out, and drying was carried out in a hot air dryer at 120° C. for 120 seconds.

[0101] Next, under the same conditions as in Example 1, rust prevention treatment and lacquering were carried out.

[0102] As a result, a fastener chain provided with the metal element according to Comparative Example 1 was obtained.Comparative Example 2

[0103] The same fastener chain as in Example 1 was prepared, and the same pretreatment as in Example 1 was carried out. Next, the pretreated fastener chain was immersed in an alkaline aqueous solution at 60° C. for 120 seconds, thereby performing alkaline immersion degreasing on the metal element. Thereafter, washing with water was carried out.

[0104] Next, electroless tin plating, rust prevention treatment and lacquer coating were carried out in this order under the same conditions as in Example 1, without carrying out any chemical conversion coating.

[0105] As a result, a fastener chain provided with the metal element according to Comparative Example 2 was obtained.Comparative Example 3

[0106] The same fastener chain as in Example 1 was prepared, and the same pretreatment as in Example 1 was carried out. Next, the pretreated fastener chain was immersed in an alkaline aqueous solution at 60° C. for 120 seconds, thereby performing alkaline immersion degreasing on the metal element. Thereafter, washing with water was carried out.

[0107] Next, the fastener chain after the degreasing treatment was immersed in a chemical conversion coating solution under the temperature and time conditions shown in Table 1, the chemical conversion coating solution having the composition shown in Table 1, thereby performing a chemical conversion coating on the metal element. Thereafter, washing with water was carried out.

[0108] Next, under the same conditions as in Example 1, electroless tin plating, rust prevention treatment and lacquer coating were carried out in this order.

[0109] As a result, a fastener chain provided with the metal element according to Comparative Example 3 was obtained.(4. Coating Analysis)

[0110] The metal elements according to the Examples and Comparative Examples fabricated above were subjected to line analysis by energy dispersive X-ray spectroscopy (SEM-EDX) from the outermost surface in the depth direction using a JSM-IT700HR scanning electron microscope manufactured by JEOL Ltd., according to the measurement conditions described above. An example of the result of the line analysis of the metal element according to Example 1 is shown in FIG. 5, and an example of the result of the line analysis of the metal element according to Example 2 is shown in FIG. 6. Based on the results of the line analysis, it was investigated whether the above-mentioned Conditions 1 to 5 were met. Further, the distance X1 in the depth direction from the outermost surface of the metal element to D1, and the distance X2 in the depth direction between D1 and D2 were also measured. The results are shown in Table 1. In addition, in all cases where Condition 1 was judged to be “satisfied,” Se, O, Sn, Cu, and Cl were detected consecutively in the depth range from D1 to D2.(5. Corrosion Resistance Evaluation)

[0111] The corrosion resistance of the metal elements after the coloring treatment was evaluated by performing a CASS test in accordance with JIS H8502: 1999 for 8 hours. The evaluation was carried out according to the following criteria. The results are shown in Table 1.

[0112] Grade 2: A wide area of the convex portions of the element has turned light brown. The concave portions of the element have turned brown. Widespread verdigris is visible.

[0113] Grade 3: Continuous white corrosion or verdigris is observed on the convex portions of the element or the concave portions of the element.

[0114] Grade 4: White corrosion or verdigris is observed intermittently on the convex portions of the element or the concave portions of the element.

[0115] Grade 5: No discolorationTABLE 1Chemical conversion solution conditionsCompositionLiquidImmersionConcentrationtemptimeCoating analysisComponents[g / L][° C.][s]Condition 1Condition 2Example 1SeO23.63545SatisfiedSatisfiedCuCl2•2H2O0.45 (CuCl2equivalent: 0.35)H2SO410.76Na2S2O86.5(also known as SPS)Example 2SeO22.53575SatisfiedSatisfiedCuCl2•2H2O0.6 (CuCl2equivalent: 0.47)H2SO42.31Na2S2O83(also known as SPS)ComparativeSeO20.3638120NotNotExample 1H2SO40.216satisfiedsatisfiedGTHComparativeN / ANotNotExample 2satisfiedsatisfiedTin platingComparativeSeO20.3638120NotNotExample 3H2SO40.216satisfiedsatisfiedGTH + TinCoating analysisCorrosionX1X2resistanceCondition 3Condition 4Condition 5[μm][μm]GradeExample 1SatisfiedSatisfiedSatisfied0.2 to 0.50.5 to 1.0CASS8h0.3 × lse ≤Se average intensity:Grade 4lcl ≤0.2 × lM to 0.6 × lM0.5 × lSeO average intensity:0.1 × lM to 0.2 × lMSn average intensity:0.2 × lM to 0.5 × lMCu average intensity:0.1 × lM to 0.3 × lMCl average intensity:0.2 × lM to 0.3 × lMExample 2SatisfiedSatisfiedSatisfied0.2 to 0.50.5 to 1.0CASS8h0.3 × lse ≤Se average intensity:Grade 4lCl ≤0.2 × lM to 0.6 × lM0.5 × lSeO average intensity:0.1 × lM to 0.2 × lMSn average intensity:0.2 × lM to 0.5 × lMCu average intensity:0.1 × lM to 0.3 × lMCl average intensity:0.2 × lM to 0.3 × lMComparativeClNotNot0.1 to 1.00.2 to 0.9CASS8hExample 1not detectedsatisfiedsatisfiedGrade 2GTHComparativeClNotNo Data0.1 to 1.00.2 to 0.9No DataExample 2not detectedsatisfiedTin platingComparativeClNotNot0.1 to 1.00.2 to 0.9CASS8hExample 3not detectedsatisfiedsatisfiedGrade 2GTH + Tin(6. Discussion)

[0116] As can be seen from the results shown in Table 1, Examples 1 and 2 showed a significant improvement in corrosion resistance compared to Comparative Examples 1 to 3.DESCRIPTION OF REFERENCE NUMERALS1: Fastener tape

[0118] 3: Metal element

[0119] 4: Upper stop

[0120] 5: Lower stop

[0121] 6: Slider

[0122] 9: Head

[0123] 9a: Convex portion

[0124] 9b: Concave portion

[0125] 10: Leg

[0126] 11: Main body

[0127] 12: Core portion

[0128] 13: Main surface

Claims

1. A chemical conversion coating solution for a metal element of a slide fastener, the chemical conversion coating solution comprising SeO2, CuCl2, H2SO4, and Na2S2O8.

2. A chemical conversion coating solution for a metal element of a slide fastener, the chemical conversion coating solution comprising 1.0 to 5.0 g / L of SeO2, 0.08 to 0.78 g / L of CuCl2, 1 to 11 g / L of H2SO4, and 1.0 to 10.0 g / L of Na2S2O8.

3. A chemical conversion coating solution for a metal element of a slide fastener, the chemical conversion coating solution comprising 2.0 to 4.0 g / L of SeO2, 0.31 to 0.63 g / L of CuCl2, 8 to 11 g / L of H2SO4, and 2.0 to 8.0 g / L of Na2S2O8.

4. A method for coloring a metal element of a slide fastener, comprising:step 1 of degreasing the metal element of the slide fastener;step 2 of subjecting the metal element of the slide fastener after the step 1 to a chemical conversion coating using the chemical conversion coating solution according to claim 1; andstep 3 of applying electroless tin plating to the metal element of the slide fastener after the step 2.

5. The method for coloring the metal element of the slide fastener according to claim 4, wherein the step 2 comprises immersing the metal element of the slide fastener after the step 1 in the chemical conversion coating solution at 20 to 50° C. for 20 to 200 seconds.

6. The method for coloring the metal element of the slide fastener according to claim 4, further comprising step 4 of subjecting the metal element of the slide fastener after the step 3 to a rust prevention treatment.

7. The method for coloring the metal element of the slide fastener according to claim 6, further comprising step 5 of lacquering the metal element of the slide fastener after the step 4.

8. The method for coloring the metal element of the slide fastener according to claim 4, further comprising step 6 of chemically polishing the metal element of the slide fastener before the step 1.

9. The method for coloring the metal element of the slide fastener according to claim 4, wherein the metal element of the slide fastener is made of a copper alloy as a base material.

10. A metal element of a slide fastener with a colored coating, satisfying the following Condition 1 when a line analysis using energy dispersive X-ray spectroscopy is performed from an outermost surface of the metal element in a depth direction,Condition 1: for a metallic element with a highest concentration that constitutes a base material of the metal element of the slide fastener, assuming an average intensity in a depth range of 2,000 to 3,000 μm from the outermost surface is IM, a depth position the closest to the outermost surface where an intensity of the metallic element is 0.4IM is D1, and a depth position the closest to the outermost surface where the intensity of the metallic element is 0.7×IM is D2, then Se, O, Sn, Cu, and Cl are detected in a depth range from D1 to D2.

11. The metal element of the slide fastener according to claim 10, further satisfying the following Condition 2,Condition 2: C is detected continuously in the depth range from D1 to D2.

12. The metal element of the slide fastener according to claim 10, further satisfying the following Condition 3,Condition 3: assuming an average intensity of Cl in the depth range from D1 to D2 is ICl and an average intensity of Se in the same depth range is ISe, then 0.2×Ise≤ICl≤0.6×ISe is satisfied.

13. The metal element of the slide fastener according to claim 10, further satisfying the following Condition 4,Condition 4: assuming a maximum intensity of Sn is ISn and a depth position the farthest from the outermost surface where an intensity of Sn is 0.5×ISn is D3, then D3 is located deeper than D2.

14. The metal element of the slide fastener according to claim 10, further satisfying the following Condition 5,Condition 5:an average intensity of Se in the depth range from D1 to D2 is 0.1×IM to 0.7×IM,an average intensity of O in the depth range from D1 to D2 is 0.1×IM to 0.3×IM,an average intensity of Sn in the depth range from D1 to D2 is 0.1×IM to 0.7×IM,an average intensity of Cu in the depth range from D1 to D2 is 0.1×IM to 0.8×IM, andan average intensity of Cl in the depth range from D1 to D2 is 0.1×IM to 0.5×IM.

15. The metal element of the slide fastener according to claim 10, wherein a distance in the depth direction from the outermost surface to D1 is 0.1 to 0.5 μm.

16. The metal element of the slide fastener according to claim 10, wherein a distance in the depth direction between D1 and D2 is 0.3 to 1.5 μm.

17. The metal element of the slide fastener according to claim 10, wherein the metallic element with the highest concentration that constitutes the base material of the metal element of the slide fastener is Cu.

18. The metal element of the slide fastener according to claim 10, wherein the base material of the metal element of the slide fastener is a copper alloy containing zinc.

19. A slide fastener comprising a row of the metal elements according to claim 10.

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