Slide fastener slider, and slide fastener

Abstract

A slide fastener slider, includes: a slider body; a puller, and a lock pin. The lock pin is made of a stainless steel material. A black oxide film is formed on a surface of the lock pin. The surface of the lock pin has brightness L* satisfying 31.70≤L*≤35.90, and a* of a value satisfying −0.708≤a*≤1.929, the brightness L′ and the a* of the value according to definitions in a CIELAB color space defined in JIS Z8781-4 (2013).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims priority under 35 USC § 119 from Japanese Patent Application No. 2024-176606 filed on Oct. 8, 2024 and Japanese Patent Application No. 2025-007268 filed on Jan. 19, 2025, the contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present invention relates to a slide fastener slider, and more particularly to a slider having a black lock pin, and a slide fastener.BACKGROUND

[0003] One type of slide fastener slider has a function of stopping the slider from moving up and down unintentionally by engaging a lock claw with an element depending on an operation state of a puller, and such a slider is sometimes referred to as a slide fastener slider with an automatic stop device, or an auto-lock slider. Among the slide fastener sliders with an automatic stop device, there is a type of slide fastener slider with an automatic stop device that includes a component (hereinafter, simply referred to as a “lock pin”) that integrates a lock claw for engaging with an element to prevent the slider from moving and a plate-shaped spring for operating the lock claw between a locked position and an unlocked position. For example, there is a slider such as that disclosed in Patent Literature 1 and Patent Literature 2.

[0004] The slider of Patent Literature 1 is a slider having a shape and structure suitable for manufacturing a slider body by zinc die casting, and the slider of Patent Literature 2 is a slider having a shape and structure suitable for manufacturing a slider body by pressing a copper-zinc alloy. A slider provided with the lock pin that integrates the lock claw and the plate-shaped spring, as described in Patent Literature 1 and Patent Literature 2, is sometimes referred to as a “semi-automatic slider” or a “semi-automatic lock slider”, and in the present specification is referred to as a “semi-automatic slider” or simply as a “slider”.

[0005] Patent Literature 1: WO2016 / 092637A1

[0006] Patent Literature 2: JP2002-010808A

[0007] In such a semi-automatic slider, since the lock pin is required to have sufficient strength to maintain the locked state and high durability against repeated elastic deformation operation, stainless steel material is widely used.

[0008] Such a semi-automatic slider can easily prevent the slide fastener from being opened accidentally, and therefore has been widely used as a slide fastener slider on a front placket of clothing such as jeans or jackets in the related art. When used for such clothing applications, in the slider of the type disclosed in Patent Literature 1, the slider body is manufactured by zinc die casting, and an original color of the zinc material is used as it is to obtain a color tone close to a silver color, which has been a common practice in the past. In addition, as in Patent Literature 2, when a copper-zinc alloy such as red brass or brass is used as a material for the slider body and the puller for clothing applications such as jeans, the copper-zinc alloy has been widely used either in the original color to obtain a color tone close to gold, or in the silver color obtained by copper-tin plated on the surface in the related art.

[0009] In the case of such clothing applications, since the lock pin made of stainless steel has a silver color tone as the original color, when the color of the slider body has a gold color tone, the lock pin made of stainless steel is subjected to a heat treatment in the atmosphere to be oxidized, thereby adjusting the color tone to the gold color tone before use. In addition, when the color of the slider body is silver, as described above, the lock pin, whose color tone has been changed to the gold color tone by being subjected to the heat treatment in the atmosphere to be oxidized, is washed with an acid to return to the original silver, making the most of the original silver color of the lock pin. In the related art, semi-automatic sliders have often been used in the manner described above. In recent years, there has been a need to use the semi-automatic slider on a bag or the like, and in such a case, the color of the slider is required to be black, which is a color frequently used in a bag or the like, in addition to the gold and silver in the related art.

[0010] Here, when making a semi-automatic slider black, although it is generally referred to as black, in reality there is not just one set of black colors, but there are various kinds of black due to differences in the absorbance and reflectance of visible light. While the lock pin is made of stainless steel, the slider body is not made of stainless steel, and the two components are assembled after being processed as separate components. Thus, the black colors of the two components are not exactly the same black, and there is a case where the two components look different. In particular, in recent years, even if the color is the same black, there are cases where a product with lower reflectance and higher absorbance of visible light, that is, a product that is uniformly pure black is preferred. In such a case, even if only some parts are not pure black, no matter how small those parts may be, the black color of those parts appears to be different from the pure black of the entire product, which may give a negative impression in terms of appearance. Further, in a case where the slide fastener is used in wetsuits or hunting wear, if a small part of the product has a different color from the rest of the product that is pure black, it may stand out, or it may stand out at certain angles because it reflects visible light, which may attract sharks or other ferocious and dangerous wild animals and may limit the uses of the slide fastener, as well as making it look unattractive.

[0011] Such a subtle difference in color tone occurs not only in black but also in colors in the related art such as gold and silver. However, in the case of a color configured of reflected light having strong directivity, such as gold and silver, it is natural that the way it look and shine change depending on the angle at which the light is reflected, and therefore, even if there is a slight difference in appearance between the color of the slider body and the color of the lock pin, there is a tendency that a sense of discomfort is unlikely to be felt. However, in the case of colors that exhibit color by absorbing visible light, such as black, a difference in color depending on the degree of blackness may be easily noticeable.

[0012] Here, there are several options for blackening a lock pin made of stainless steel, including plating or painting. In the case of plating, in order to form a black plating layer with sufficient adhesion to a stainless steel material, it is necessary to apply several undercoat treatment layers on top of a stainless steel base material, which has the disadvantage that the manufacturing process is complicated and the manufacturing cost is high. In addition, in the case of painting, the disadvantage to be taken into consideration is that the lock pin is a component that is strongly subjected to friction and elastic deformation, and therefore there is a risk of peeling off.

[0013] The present invention is conceived by focusing on the discomfort felt by people due to subtle differences in color of such black components. An object of the present invention is to provide a lock pin of a slide fastener, which is devised to have a black color that is integrated with peripheral components without a sense of discomfort, using a method that requires less manufacturing cost, and that has sufficient adhesive strength.SUMMARY

[0014] A slide fastener slider, includes: a slider body; a puller; and a lock pin, in which the lock pin is made of a stainless steel material, a black oxide film is formed on a surface of the lock pin, and the surface of the lock pin has brightness L* satisfying 31.70≤L*≤35.90, and a* of a value satisfying −0.708≤a*≤1.929, the brightness L* and the a* of the value according to definitions in a CIELAB color space defined in JIS Z8781-4 (2013).

[0015] Further, the surface of the lock pin has b* of a value satisfying −2.428≤b*≤0.466, the b* of the value according to a definition in the CIELAB color space defined in JIS Z8781-4 (2013).

[0016] It is preferable that the stainless steel material for the lock pin is an austenitic stainless steel material containing 10 wt % to 14 wt % of nickel, and the surface of the lock pin has the brightness L* satisfying 31.70≤L*≤34.16, the a* of the value satisfying 0.369≤a*≤1.736, and b* of a value satisfying −2.428≤b*≤0.466, the brightness L*, the a* of the value and the b* of the value according to definitions in the CIELAB color space defined in JIS Z8781-4 (2013). Alternatively, the stainless steel material for the lock pin is an austenitic stainless steel material containing 13 wt % to 17 wt % of manganese, and the surface of the lock pin has the brightness L* satisfying 33.04≤L*≤35.90, the a* of the value satisfying −0.708≤a*≤1.929, and b* of a value satisfying −2.388≤b*≤−1.495, the brightness L*, the a* of the value and the b* of the value according to definitions in the CIELAB color space defined in JIS Z8781-4 (2013).

[0017] Further, it is preferable that the slider body is black, and according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013), a difference ΔL* between brightness L* of the slider body and brightness L* of the lock pin satisfies ΔL*≤8.54, and a difference Δa* between a* of a value of the slider body and a* of a value of the lock pin satisfies 0.03≤Δa*≤2.67.

[0018] Further, it is preferable that when the stainless steel material for the lock pin is an austenitic stainless steel material containing 10 wt % to 14 wt % of nickel, the slider body is black, and according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013), a difference ΔL* between brightness L* of the slider body and brightness L* of the lock pin satisfies ΔL*≤6.79, and a difference Δa* between a* of a value of the slider body and a* of a value of the lock pin satisfies 1.11≤Δa*≤2.47. Further, it is preferable that when the stainless steel material for the lock pin is an austenitic stainless steel material containing 13 wt % to 17 wt % of manganese, the slider body is black, and according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013), a difference ΔL* between brightness L* of the slider body and brightness L* of the lock pin satisfies ΔL*≤8.54, and a difference Δa* between a* of a value of the slider body and a* of a value of the lock pin satisfies 0.03≤Δa*≤2.67.

[0019] Further, it is preferable that a slide fastener includes: the slide fastener slider described above, in which an element of the slide fastener is made of a ferritic stainless steel material, and the element has brightness L* satisfying 29.67≤L*≤36.24, a* of a value satisfying −0.63≤a*≤0.76, and b* of a value satisfying 0.42≤b*≤1.22, the brightness L*, the a* of the value and the b* of the value according to definitions in the CIELAB color space defined in JIS Z8781-4 (2013). In this case, it is more preferable that the slider body is black, and according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013), a difference ΔL* between the brightness L* of the element and brightness L* of the slider body satisfies ΔL*≤8.94, and a difference Δa* between values of a* thereof satisfies 0.11≤Δa*≤1.49.

[0020] Further, in the slide fastener slider according to the embodiment of the present invention, the oxide film on the surface of the lock pin has a thickness of 320 nm or more and 1870 nm or less. In some embodiments, the stainless steel material for the lock pin is an austenitic stainless steel material containing 10 wt % or more and 14 wt % or less of nickel, and a thickness of the oxide film on the surface of the lock pin (21, 31) is 320 nm or more and 1260 nm or less. In some other embodiments, the stainless steel material for the lock pin is an austenitic stainless steel material containing 13 wt % or more and 17 wt % or less of manganese, and a thickness of the oxide film on the surface of the lock pin is 440 nm or more and 1870 nm or less. In a slide fastener using the slide fastener slider according to the embodiment of the present invention, it is preferable that a thickness of an oxide film on the element of the slide fastener is 1010 nm or more and 2700 nm or less.BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a perspective view of a slide fastener slider according to a first embodiment of the present invention.

[0022] FIG. 2 is a diagram for illustrating three components forming the slide fastener slider according to the first embodiment of the present invention in an exploded state.

[0023] FIG. 3 is a perspective view of a slide fastener slider according to a second embodiment of the present invention.

[0024] FIG. 4 is a diagram for illustrating three components forming the slide fastener slider according to the second embodiment of the present invention in an exploded state.

[0025] FIG. 5 is a schematic diagram showing an oxide film formed on a surface of a lock pin of the slide fastener slider according to the present invention.

[0026] FIG. 6 is a graph showing results of a distribution state of metal elements contained in a black oxide film formed on a surface of a lock pin of Example 1-16 analyzed in a depth direction by Auger electron spectroscopy.

[0027] FIG. 7 is a graph for Example 1-17, as in the foregoing.

[0028] FIG. 8 is a graph for Example 1-18, as in the foregoing.

[0029] FIG. 9 is a graph for Example 1-19, as in the foregoing.

[0030] FIG. 10 is a graph for Example 1-20, as in the foregoing.

[0031] FIG. 11 is a graph for Example 1-21, as in the foregoing.

[0032] FIG. 12 is a graph for Example 2-16, as in the foregoing.

[0033] FIG. 13 is a graph for Example 2-17, as in the foregoing.

[0034] FIG. 14 is a graph for Example 2-18, as in the foregoing.

[0035] FIG. 15 is a graph for Example 2-19, as in the foregoing.

[0036] FIG. 16 is a graph for Example 2-20, as in the foregoing.

[0037] FIG. 17 is a graph for Example 2-21, as in the foregoing.

[0038] FIG. 18 is a graph for Comparative Example 1-2, as in the foregoing.

[0039] FIG. 19 is a graph for Comparative Example 1-3, as in the foregoing.

[0040] FIG. 20 is a graph for Comparative Example 2-2, as in the foregoing.

[0041] FIG. 21 is a graph for Comparative Example 2-3, as in the foregoing.

[0042] FIG. 22 is a graph for Comparative Example 3, as in the foregoing.

[0043] FIG. 23 is a graph showing results of a distribution state of metal elements contained in a black oxide film formed on a surface of a slide fastener element of Example 3-16 analyzed in a depth direction by Auger electron spectroscopy.

[0044] FIG. 24 is a graph for Example 3-17, as in the foregoing.

[0045] FIG. 25 is a graph for Example 3-18, as in the foregoing.

[0046] FIG. 26 is a graph for Example 3-19, as in the foregoing.

[0047] FIG. 27 is a graph for Example 3-20, as in the foregoing.

[0048] FIG. 28 is a graph for Example 3-21, as in the foregoing.DESCRIPTION OF EMBODIMENTS

[0049] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0050] FIG. 1 is a perspective view of a slide fastener slider 20 according to a first embodiment of the present invention. As shown in FIG. 2, the slider 20 includes at least three components of a lock pin 21, a slider body 23, and a puller 25. The slider body 23 of the slider 20 of the type shown in FIG. 1 is a slider having a shape and structure suitable for manufacturing by die casting using a zinc material. The lock pin 21 is required to have sufficient strength to maintain a stopped locked state of the slider 20 and also to have high durability against repeated elastic deformation operation, and therefore is manufactured from stainless steel. The puller 25 is made of a suitable material such as zinc or a copper-zinc alloy. The lock pin 21, the slider body 23, and the puller 25 are each manufactured as separate components in separate processes, and then the puller 25 is attached to the slider body 23 by clamping, and the lock pin 21 is attached to the body 23, thereby forming the slider 20 as a finished product.

[0051] In the present embodiment, in the manufacturing process of each component of the lock pin 21, the slider body 23, and the puller 25, the lock pin 21, the slider body 23, and the puller 25 are all colored to exhibit a black appearance. The body 23 is preferably colored black by painting. A metal portion of the puller 25 may also be colored by painting, and if necessary, a black rubber material may be integrally molded around the metal portion to form a black rubber puller as a whole. The slider body 23 and the puller 25 may be colored black by plating or chemical conversion treatment instead of painting. The lock pin 21 may be colored black by painting or plating, but in the present embodiment, the lock pin 21 is colored black by chemical conversion treatment. The blackening treatment of the lock pin 21 will be described in more detail later.

[0052] FIG. 3 is a perspective view of a slide fastener slider 30 according to a second embodiment of the present invention. As shown in FIG. 4, the slider 30 includes at least three components of a lock pin 31, a slider body 33, and a puller 35. The slider body 33 of the slider 30 of the type shown in FIG. 3 has a shape and structure suitable for manufacturing by pressing a copper-zinc alloy. The lock pin 31 is required to have sufficient strength to maintain a stopped locked state of the slider 30 and also to have high durability against repeated elastic deformation operation, and therefore is manufactured from stainless steel. The puller 35 is made of a suitable material such as a copper-zinc alloy. The lock pin 31, the slider body 33, and the puller 35 are each manufactured as separate components in separate processes, and then the puller 35 and the lock pin 31 are attached to the slider body 33 to form the slider 30 as a finished product.

[0053] In the second embodiment of the present invention, in the manufacturing process of each component of the lock pin 31, the slider body 33, and the puller 35, the lock pin 31, the slider body 33, and the puller 35 are also all colored to exhibit a black appearance. The body 33 and the puller are preferably colored black by plating, may also be colored black by painting or chemical conversion treatment. The lock pin 31 may also be colored by plating or painting, but in the present embodiment, the lock pin 31 is colored black by chemical conversion treatment.

[0054] Note that the slider 20, 30 having a structure including at least three components as shown in FIGS. 1 to 4 may be referred to as a “semi-automatic slider” or a “semi-automatic lock slider” as described above, but in the present specification, the slider 20, 30 is simply referred to as a “slider 20, 30”.

[0055] Next, the blackening treatment of the lock pin 21, 31 in the embodiments of the present invention will be described. When the lock pin 21, 31 made of stainless steel is to be blackened with respect to the black slider body 23, 33, methods such as painting, plating, and chemical conversion treatment are conceivable as a method for blackening the lock pin 21, 31. However, when painting is used for blackening treatment of the lock pin 21, 31 made of stainless steel, since the lock pin is a member that undergoes repeated elastic deformation or a component that is subjected to strong friction due to metal contact with a puller, washing, or the like, the paint on the lock pins is prone to peeling, and a quality defect is likely to occur over long-term use. In addition, when plating is used for the blackening treatment of the lock pin 21, 31 made of stainless steel, it is difficult to directly laminate a black plating layer on a stainless steel base material with good adhesion, and thus it is necessary to apply several layers of primer plating for enhancing the adhesion, which has the disadvantage of increasing manufacturing cost. In addition, whether painted or plated, in order to obtain a black color with low reflectance and high absorbance of visible light, it is necessary to increase a painting film thickness or a plating film thickness, which has the disadvantage that the texture of the stainless steel material of the lock pin is lost due to the coating. For this reason, in the present invention, an oxide film is formed by chemical conversion treatment during blackening treatment of the lock pin 21, 31. FIG. 5 is a schematic diagram showing an oxide film formed on a surface of the lock pin 21, 31 of the slide fastener slider according to the present invention. An oxide film 53 is formed on a surface of a base material 51 of the lock pin 21, 31.

[0056] In related art, attempts have been made to blacken the lock pin 21, 31 by the chemical conversion treatment, and it has been possible to blacken the lock pin 21, 31 through a relatively simple process. A widely used chemical conversion treatment is a method including pretreatment processes such as polishing, heat treatment, and removal of any naturally formed oxide film on a component pressed from stainless steel, followed by immersion in an acidic solution (a chromic acid-based solution) or an alkaline solution (a caustic soda-based solution) to form an oxide film, and then cleaning and drying as a post-treatment.

[0057] However, even if the oxide film is formed by the chemical conversion treatment, depending on the condition of the oxide film and the angle at which the lock pin 21, 31 is viewed, the color tone may not be completely black (black exhibited by an object that completely absorbs visible light) due to the degree of reflection of light, but rather appears closer to brown due to the reflection of a part of visible light. In such a case, depending on a viewing angle, the black color of the fastener using product (bags, clothes, or the like), the black color of the slider body 23, 33, and the black color of the lock pin 21, 31 do not appear to be the same black color, which causes a sense of discomfort in appearance. The reason for this is that it has not been possible to make the oxide film thick enough to sufficiently reduce the reflection of the visible light to the point where it becomes almost completely black, and to sufficiently absorb visible light to the point where it becomes almost completely black. Therefore, in the present invention, an oxide film thickness is formed to a thickness that is sufficient to reduce the reflection of the visible light to the point that it is almost completely black, which is not possible in the lock pin 21, 31 according to the chemical conversion treatment in the related art.

[0058] Next, results of measuring the brightness and hue of the lock pin 21, 31 according to the embodiment of the present invention will be described.

[0059] As factors for evaluating the degree of blackness of the slider 20, 30 and the lock pin 21, 31 in the embodiments of the present invention, a value a*, a value b*, and a value L* in the CIELAB color space defined in JIS Z8781-4 (2013) were used. Here, a* and b* are color tones defined in the CIELAB color space defined in JIS Z8781-4 (2013). a* represents a magenta-green color tone (+ is closer to magenta, —is closer to green), and b* represents a yellow-blue color tone (+ is closer to yellow, —is closer to blue). In addition, L* indicates brightness defined in the CIELAB color space defined in JIS Z8781-4 (2013), and the higher the value, the higher the gloss. The color measurement was performed using an RTC-21 manufactured by Ikegami Tsushinki Co., Ltd. The light source is an LED light.

[0060] Example 1-1 to Example 1-15 shown in Table 1 are the lock pin 21, 31 according to the embodiment of the present invention, which are manufactured from a nickel-based austenitic stainless steel material containing 10% to 14% of nickel, and more specifically, the lock pins 21, 31 according to the embodiment of the present invention, which are manufactured by a nickel-based austenitic stainless steel material containing 12 weight percent of nickel, 20 weight percent of chromium, and 3 weight percent of manganese. The external appearance of each of Example 1-1 to Example 1-15 is a deep and rich black color, and there is almost no change in the appearance depending on a reflection angle of light. Table 1 shows the results of measuring the value of the brightness L*, the value of a*, and the value of b* of Example 1-1 to Example 1-15, and the results of comparing them with the value of the brightness L*, the value of a*, and the value of b* of the slider body 23, 33.

[0061] “Difference in brightness ΔL* from body” indicates a value obtained by subtracting the “brightness L* of slider body” from the “measured value of brightness L* of each example”, “color difference Δa* from body” indicates a value obtained by subtracting the “measured value of a* of slider body” from the “measured value of a* of each example”, and “color difference Δb* from body” indicates a value obtained by subtracting the “measured value of b* of slider body” from the “measured value of b* of each example” (hereinafter, the same applies to Tables 2, 3, and 4).

[0062] Example 2-1 to Example 2-15 shown in Table 2 are the lock pin 21, 31 according to the embodiment of the present invention, which are manufactured from a manganese-based austenitic stainless steel material containing 13% to 17% of manganese, and more specifically, the lock pins 21, 31 according to the embodiment of the present invention, which are manufactured by a manganese-based austenitic stainless steel material containing 15 weight percent of manganese, 4 weight percent of nickel, and 17 weight percent of chromium. The external appearance of each of Example 2-1 to Example 2-15 is a deep and rich black color, and there is almost no change in the appearance depending on a reflection angle of light. Table 2 shows the results of measuring the value of the brightness L*, the value of a*, and the value of b* of Example 2-1 to Example 2-15, and the results of comparing them with the value of the brightness L*, the value of a*, and the value of b* of the slider body 23, 33.

[0063] Example 3-1 to Example 3-15 shown in Table 3 are embodiments in which a test piece (a test piece having a shape of a slide fastener element) made of a ferritic stainless steel material (SUS430) was subjected to blackening treatment by chemical conversion treatment in the same manner as in the above Examples. The external appearance of each of Example 3-1 to Example 3—is a deep and rich black color, and there is almost no change in the appearance depending on a reflection angle of light. Table 3 shows the results of measuring the value of the brightness L*, the value of a*, and the value of b* of Example 3-1 to Example 3-15, and the results of comparing them with the value of the brightness L*, the value of a*, and the value of b* of the slider body 23, 33.TABLE 1DifferenceColorColorΔL* indifferencedifferencebrightnessΔa* fromΔb* fromL*a*b*from bodybodybodyExample 1-133.561.193−0.0026.201.930.42Example 1-233.631.186−0.6516.261.92−0.23Example 1-334.161.1860.4666.791.920.89Example 1-434.161.468−0.0336.792.210.39Example 1-533.720.992−0.7736.351.73−0.35Example 1-633.280.668−2.1875.921.41−1.76Example 1-733.270.369−1.7455.911.11−1.32Example 1-832.980.989−1.8115.621.73−1.39Example 1-933.200.763−1.8095.831.50−1.39Example 1-1033.370.458−2.4286.011.20−2.00Example 1-1132.001.502−1.6914.642.24−1.27Example 1-1232.281.652−1.3154.922.39−0.89Example 1-1331.871.736−1.9884.512.47−1.56Example 1-1432.161.730−1.2894.802.47−0.87Example 1-1531.701.208−1.3614.341.95−0.94TABLE 2ColorColorDifference ΔL*differencedifferencein brightnessΔa* fromΔb* fromL*a*b*from bodybodybodyExample 2-135.631.230−1.5628.271.97−1.14Example 2-235.901.111−1.8428.541.85−1.42Example 2-335.481.929−1.6418.122.67−1.22Example 2-435.541.505−2.2328.182.24−1.81Example 2-535.661.510−2.0808.302.25−1.66Example 2-635.760.126−2.3818.400.86−1.96Example 2-735.32−0.113−2.3887.960.62−1.96Example 2-835.050.492−2.3407.691.23−1.92Example 2-935.32−0.708−1.4957.960.03−1.07Example 2-1035.40−0.397−1.7678.040.34−1.34Example 2-1133.75−0.029−2.2746.380.71−1.85Example 2-1233.130.064−2.0925.770.80−1.67Example 2-1333.040.031−1.9235.680.77−1.50Example 2-1433.43−0.022−2.0066.070.72−1.58Example 2-1533.490.060−1.7746.130.80−1.35TABLE 3ColorColorDifference ΔL*differencedifferencein brightnessΔa* fromΔb* fromL*a*b*from bodybodybodyExample 3-136.170.460.928.801.201.34Example 3-236.240.331.228.881.071.65Example 3-335.950.311.048.581.051.47Example 3-436.310.641.078.941.381.50Example 3-536.130.761.208.771.491.62Example 3-633.63−0.501.086.270.241.50Example 3-733.58−0.021.186.220.721.60Example 3-833.620.261.066.261.001.48Example 3-933.450.281.196.091.021.61Example 3-1034.420.051.337.060.791.76Example 3-1129.75−0.420.422.390.320.84Example 3-1230.90−0.360.703.540.381.13Example 3-1329.67−0.630.602.310.111.02Example 3-1429.92−0.580.542.560.160.97Example 3-1530.20−0.350.652.830.381.08The slider body 23, 33 is a slider that is blackened by painting, and is painted with a paint that is used for the black color and has low reflectance and high absorbance for visible light. The value of the brightness L* of the black color was L*=27.36, and the value of a* and the value of b* were a*=−0.738 and b*=−0.424.Although the lock pin 21, 31 of Example 1-1 to Example 2-15 and the slider body 23, 33 are made of different materials and treated as separate components, colored, and then assembled, the difference (ΔL*) in brightness L* between the slider body 23, 33 and the lock pin 21, 31 is kept to a low range, ΔL*≤8.54. The “color difference Δa* from body” and the “color difference Δb* from body” are also kept low within an allowable range, and in particular, the difference (Δa*) in the value of a* is kept low, within a range of 0.03≤Δa*≤2.67. As a result, the appearance is less likely to give the impression that there is a significant difference in the way the black colors of the two components look. In addition, the absolute value of the brightness L* satisfies 31.70≤L*≤35.90, and the value of a* and the value of b* satisfy −0.708≤a*≤1.929 and −2.428≤b*≤0.466, respectively. Therefore, the black color of the lock pin 21, 31 is a black color that has lower reflectance and higher absorbance of visible light than the same black color, which is called a pure black color, so that even if the lock pin 21, 31 is used as a component of a slide fastener slider in a product with a concept that the entire product is pure black, the lock pin 21, 31 does not stand out and give a different impression. In some examples, there is an example in which the difference (ΔL*) in brightness L* between the slider body 23, 33 and the lock pin 21, 31 exceeds 6.3, resulting in a slightly brighter brightness difference. However, since the difference (Δa*) in the value of a* therebetween is kept to a low range of less than 2.7, there is no discomfort such as the color appearing reddish brown depending on the reflection angle of light.

[0066] In particular, the difference (ΔL*) in brightness L* between the lock pin 21, 31 made of the nickel-based austenitic stainless steel material in Example 1-1 to Example 1-15 and the slider body 23, 33 is kept to a low range of 4.34≤ΔL*≤6.79. The “color difference Δa* from body” and the “color differenceΔb* from body” are also kept low within an allowable range, and in particular, the difference (Δa*) in the value of a* is kept low, within a range of 1.11≤Δa*≤2.47. As a result, the appearance is less likely to give the impression that there is a significant difference in the way the black colors of the two components look. In addition, the absolute value of the brightness L* satisfies 31.70≤L*≤34.16, and the value of a* and the value of b* satisfy 0.369≤a*≤1.736 and −2.428≤b*≤0.466, respectively. Therefore, the black color of the lock pin 21, 31 is a black color in a range that has lower reflectance and higher absorbance of visible light than the same black color, which is called a pure black color, so that even if the lock pin 21, 31 is used as a component of a slide fastener slider in a product with a concept that the entire product is pure black, the lock pin 21, 31 does not stand out and give a different impression.

[0067] In particular, the difference (ΔL*) in brightness L* between the lock pin 21, 31 made of the manganese-based austenitic stainless steel material in Example 2-1 to Example 2-15 and the slider body 23, 33 is kept to a low range of 5.68≤ΔL*≤8.54. The “color difference Δa* from body” and the “color difference Δb* from body” are also kept low within an allowable range, and in particular, the difference (Δa*) in the value of a* is kept low, within a range of 0.03≤Δa*≤2.67. As a result, the appearance is less likely to give the impression that there is a significant difference in the way the black colors of the two components look. In addition, the absolute value of the brightness L* satisfies 33.04≤L*≤35.90, and the value of a* and the value of b* satisfy-0.708≤a*≤1.929 and −2.388≤b*≤−1.495, respectively. Therefore, the black color of the lock pin 21, 31 is a black color in a range that has lower reflectance and higher absorbance of visible light than the same black color, which is called a pure black color, so that even if the lock pin 21, 31 is used as a component of a slide fastener slider in a product with a concept that the entire product is pure black, the lock pin 21, 31 does not stand out and give a different impression.

[0068] Further, similarly to the lock pin 21, 31, the test pieces (test pieces having a shape of a slide fastener element) made of the ferritic stainless steel material (SUS430) of Example 3-1 to Example 3-15 also have the difference (ΔL*) in brightness L* kept to a low range of 2.31≤ΔL*≤8.94. The “color difference Δa* from body” and the “color difference Δb* from body” are also kept low within an allowable range, and in particular, the difference (Δa*) in the value of a* is kept low, within a range of 0.11≤Δa*≤1.49. As a result, the appearance is less likely to give the impression that there is a significant difference in the way the black colors of the two components look. In addition, the absolute value of the brightness L* satisfies 29.67≤L*≤36.24, and the value of a* and the value of b* satisfy −0.63≤a*≤0.76 and 0.42≤b*≤1.22, respectively. Therefore, by using not only the sliders 20, 30 but also the slide fastener element of Example 3-1 to Example 3-15, in a product with a concept in which the product is entirely pure black, the elements of the slide fastener no longer stands out and gives a different impression, and the slide fastener as a whole can give a unified impression of black.

[0069] In contrast, a similar color measurement was carried out on a comparative example of a lock pin that was blackened by chemical conversion treatment but in which the degree of blackening was insufficient (that is, a comparative example with a black color that is not sufficiently low in reflectance and is not sufficiently high in absorbance for visible light). The results are shown below.TABLE 4ColorColorDifference ΔL*differencedifferencein brightnessΔa* fromΔb* fromL*a*b*from bodybodybodyComparative33.714.67−0.166.355.400.26example 1Comparative43.4818.8910.5816.119.611.0example 2

[0070] The lock pin of Comparative Example 1 in Table 4 has a black appearance that is slightly reddish black compared to those of Example 1-1 to Example 2-15 above, and appears reddish brown depending on the reflection angle of light. The lock pin of Comparative Example 1 has a difference (ΔL*) in brightness L* from the slider body 23, 33 of ΔL*=6.35, which is slightly high, and the color difference Δa* from the body is 5.40, which is also high. Therefore, it gives an impression that there is a large difference in how the black color looks compared to the slider body. In addition, the absolute value of the brightness L* satisfies L*=33.71, and the value of a* and the value of b* satisfy a*=4.67 and b*=−0.16, respectively. Therefore, the black color of the lock pin is not a black color in a range that has lower reflectance and higher absorbance of visible light than the same black color, which is called a pure black color, and when the lock pin is used as a component of a slide fastener slider in a product with a concept that the entire product is pure black, the lock pin stands out and gives a different impression.

[0071] The lock pin of Comparative Example 2 in Table 4 has an appearance closer to brown than black, and also appears brown depending on the reflection angle of light. The lock pin of Comparative Example 2 has an extremely high difference (ΔL*) in brightness L* from the slider body 23, 33 of ΔL*=16.1, and the color difference Δa* from the body is 19.6, which is also high. Therefore, it gives an impression that there is a large difference in how the black color looks compared to the slider body. In addition, the absolute value of the brightness L* satisfies L*=43.48, and the value of a* and the value of b* satisfy a*=18.89 and b*=10.58, respectively. Therefore, color of the lock pin is closer to brown instead of black, and when the lock pin is used as a component of a slide fastener slider in a product with a concept that the entire product is pure black, the lock pin stands out and gives a different impression.

[0072] In contrast, the sliders 20, 30 of the present invention have the configuration described above. Therefore, even when the lock pin 21, 31 subjected to the chemical conversion treatment in black is used as a component of a slide fastener slider in a product with a concept that the entire product is pure black, an impression that only the lock pin 21, 31 stands out in a different color is not given. Further, when a similar black oxide film is also provided on the fastener element made of stainless steel, the slide fastener as a whole can be given a unified black impression.

[0073] Next, the state of a film thickness of the oxide film formed on the surface of the lock pin 21, 31 or the test piece (test piece having a shape of a slide fastener element) in the embodiments of the present invention will be described with reference to FIGS. 6 to 23.

[0074] FIGS. 6 to 17 are graphs showing results of a distribution state of metal elements contained in the black oxide film 53 formed on the surface of the lock pin 21, 31 according to the embodiment of the present invention analyzed in a depth direction by Auger electron spectroscopy. FIGS. 18 to 23 are graphs showing results of a distribution state of metal elements contained in the black oxide film 53 formed on a surface of the test piece (test piece having a shape of a slide fastener element) in the embodiment of the present invention analyzed in the depth direction by Auger electron spectroscopy.

[0075] First, FIGS. 6 to 11 will be described. FIG. 6 to FIG. 11 show the results of analyzing the lock pin 21, 31 according to the embodiment of the present invention, which are made of a nickel-based austenitic stainless steel material containing 10% to 14% of nickel, as in Example 1-1 to Example 1-15 shown in Table 1 above. For convenience, the example sample analyzed in FIG. 6 is referred to as Example 1-16, the example sample analyzed in FIG. 7 is referred to as Example 1-17, the example sample analyzed in FIG. 8 is referred to as Example 1-18, the example sample analyzed in FIG. 9 is referred to as Example 1-19, the example sample analyzed in FIG. 10 is referred to as Example 1-20, and the example sample analyzed in FIG. 11 is referred to as Example 1-21. Here, to explain in detail the relationship between the example samples of Example 1-1 to Example 1-15 shown in Table 1 and the example samples of Example 1-16 to Example 1-21 for which film thickness data was acquired by Auger electron spectroscopy, the Example 1-1 to Example 1-5 in Table 1, and Example 1-16 (FIG. 6) and Example 1-17 (FIG. 7) for which film thickness data was acquired by Auger electron spectroscopy are example samples from a group subjected to the chemical conversion treatment as the same production lot. That is, when a small component such as the lock pin is subjected to a chemical conversion treatment, several hundreds of lock pins are subjected to the chemical conversion treatment all at once, and from the several hundreds of production lots that are subjected to the chemical conversion treatment all at once, seven lock pins, designated as Example 1-1, Example 1-2, Example 1-3, Example 1-4, and Example 1-5 which are shown in Table 1, and Example 1-16 (FIG. 6) and Example 1-17 (FIG. 7) for which the film thickness data was acquired by Auger electron spectroscopy, were randomly sampled for the purpose of acquiring measurement data.

[0076] Similarly, seven lock pins, designated as Example 1-6, Example 1-7, Example 1-8, Example 1-9, and Example 1-10 which are shown in Table 1, and Example 1-18 (FIG. 8) and Example 1-19 (FIG. 9) for which the film thickness data was acquired by Auger electron spectroscopy, belong to a group subjected to the chemical conversion treatment as the same production lot. Similarly, seven lock pins, designated as Example 1-11, Example 1-12, Example 1-13, Example 1-14, and Example 1-15 which are shown in Table 1, and Example 1-20 (FIG. 10) and Example 1-21 (FIG. 11) for which the film thickness data was acquired by Auger electron spectroscopy, belong to a group subjected to the chemical conversion treatment as the same production lot.

[0077] FIG. 6 will be described. FIG. 6 is a graph showing the change in the proportion of each metal element in the thickness direction of the oxide film layer of the lock pin 21. The thickness of the oxide film can be estimated by observing the changes in the distribution of oxygen (O) along with the component elements of iron (Fe), manganese (Mn), chromium (Cr), nickel (Ni), carbon (C), and silicon (Si) contained in the stainless steel material as the base material. In the present specification, the thickness in the depth direction up to the point where the amount of oxygen formed on the sample is 50% of the amount (maximum value) in the vicinity of the surface is defined as the thickness of the oxide film for convenience (hereinafter, simply referred to as “thickness of the oxide film” or “film thickness”). For example, in FIG. 6, the maximum value of the amount of oxygen in the vicinity of the surface formed in the sample is about 3500 on the vertical axis (Intensity), and the depth at which 50% of this value, 1750, is 340 nm, is taken as the thickness of the oxide film.

[0078] That is, the thickness of the oxide film of Example 1-16 is 340 nm.

[0079] Similarly, for the film thickness of the oxide film, the thickness of the oxide film of Example 1-17 shown in FIG. 7 is 320 nm. The thickness of the oxide film of Example 1-18 shown in FIG. 8 is 530 nm. The thickness of the oxide film of Example 1-19 shown in FIG. 9 is 480 nm. The thickness of the oxide film of Example 1-20 shown in FIG. 10 is 1260 nm. The thickness of the oxide film of Example 1-21 shown in FIG. 11 is 1010 nm.

[0080] The distribution range of the thickness of the oxide film of the six example samples, Example 1-16 to Example 1-21, is 320 nm or more and 1260 nm or less.

[0081] Next, FIGS. 12 to 17 will be described. FIG. 12 to FIG. 17 show the results of analyzing the lock pin 21, 31 according to the embodiment of the present invention, which are made of a manganese-based austenitic stainless steel material containing 13% to 17% of manganese, as in Example 2-1 to Example 2-15 shown in Table 2 above. For convenience, the example sample analyzed in FIG. 12 is referred to as Example 2-16, the example sample analyzed in FIG. 13 is referred to as Example 2-17, the example sample analyzed in FIG. 14 is referred to as Example 2-18, the example sample analyzed in FIG. 15 is referred to as Example 2-19, the example sample analyzed in FIG. 16 is referred to as Example 2-20, and the example sample analyzed in FIG. 16 is referred to as Example 2-21. Here, to explain in detail the relationship between the example samples of Example 2-1 to Example 2-15 shown in Table 2 and the example samples of Example 2-16 to Example 2-21 for which film thickness data was acquired by Auger electron spectroscopy, Example 2-1 to Example 2-5 in Table 2, and Example 2-16 (FIG. 12) and Example 2-17 (FIG. 13) for which film thickness data was acquired by Auger electron spectroscopy are example samples from a group subjected to the chemical conversion treatment as the same production lot. That is, when a small component such as the lock pin is subjected to a chemical conversion treatment, several hundreds of lock pins are subjected to the chemical conversion treatment all at once, and from the several hundreds of production lots that are subjected to the chemical conversion treatment all at once, seven lock pins, designated as Example 2-1, Example 2-2, Example 2-3, Example 2-4, and Example 2-5 which are shown in Table 2, and Example 2-16 (FIG. 12) and Example 2-17 (FIG. 13) for which the film thickness data was acquired by Auger electron spectroscopy, were randomly sampled for the purpose of acquiring measurement data.

[0082] Similarly, seven lock pins, designated as Example 2-6, Example 2-7, Example 2-8, Example 2-9, and Example 2-10 which are shown in Table 2, and Example 2-18 (FIG. 14) and Example 2-19 (FIG. 15) for which the film thickness data was acquired by Auger electron spectroscopy, belong to a group subjected to the chemical conversion treatment as the same production lot. Similarly, seven lock pins, designated as Example 2-11, Example 2-12, Example 2-13, Example 2-14, and Example 2-15 which are shown in Table 2, and Example 2-20 (FIG. 16) and Example 2-21 (FIG. 17) for which the film thickness data was acquired by Auger electron spectroscopy, belong to a group subjected to the chemical conversion treatment as the same production lot.

[0083] The definition of the thickness of the oxide film read from the measurement data in FIGS. 12 to 17 is the same as the method described with reference to FIG. 6. That is, in FIG. 12, the maximum value of the amount of oxygen in the vicinity of the surface formed in the sample is about 3750 on the vertical axis (Intensity), and the depth at which 50% of this value, 1875, is 440 nm, is taken as the thickness of the oxide film.

[0084] That is, the thickness of the oxide film of Example 2-16 is 440 nm.

[0085] Similarly, for the film thickness of the oxide film, the thickness of the oxide film of Example 2-17 shown in FIG. 13 is 570 nm. The thickness of the oxide film of Example 2-18 shown in FIG. 14 is 840 nm. The thickness of the oxide film of Example 2-19 shown in FIG. 15 is 860 nm. The thickness of the oxide film of Example 2-20 shown in FIG. 16 is 1870 nm. The thickness of the oxide film of Example 2-21 shown in FIG. 17 is 1830 nm.

[0086] The distribution range of the thickness of the oxide film of the six example samples, Example 2-16 to Example 2-21, is 440 nm or more and 1870 nm or less.

[0087] On the other hand, a comparative example in which the oxide film thickness is not enough to sufficiently reduce the reflection of visible light to nearly completely black will be described below with reference to FIGS. 18 to 21 in the same manner as the embodiments described above.

[0088] FIGS. 18 and 19 show the results of the Auger electron spectroscopy analysis performed in the same manner as in the above examples on a sample extracted from the lock pins subjected to the chemical conversion treatment in the same production lot as Comparative Example 1. For convenience, the sample analyzed in FIG. 18 is referred to as Comparative Example 1-2, and the sample analyzed in FIG. 19 is referred to as Comparative Example 1-3. When an estimated value of the film thickness is obtained by analyzing Comparative Example 1-2 and Comparative Example 1-3 by Auger electron spectroscopy in the same manner as described above, it can be seen that the oxide film thickness in Comparative Example 1-2 is about 2020 nm, and the oxide film thickness of Comparative Example 1-3 is about 2300 nm. That is, it can be seen that the film thickness of Comparative Example 1 was too thick compared to the film thickness distribution range of Examples of the present invention.

[0089] FIGS. 20 and 21 show the results of the Auger electron spectroscopy analysis performed in the same manner as in the above examples on a sample extracted from the lock pins subjected to the chemical conversion treatment in the same production lot as Comparative Example 2. For convenience, the sample analyzed in FIG. 20 is referred to as Comparative Example 2-2, and the sample analyzed in FIG. 21 is referred to as Comparative Example 2-3. When an estimated value of the film thickness is obtained by analyzing Comparative Example 2-2 and Comparative Example 2-3 by Auger electron spectroscopy in the same manner as described above, it can be seen that the oxide film thickness in Comparative Example 2-2 is about 40 nm, and the oxide film thickness of Comparative Example 2-3 is about 60 nm. That is, it can be seen that the film thickness of Comparative Example 2 was too thin compared to the film thickness distribution range of Examples of the present invention.

[0090] Further, the lock pin was made of a stainless steel material containing 10% or more and 14% or less of nickel in percent by weight as in Comparative Example 2, but another sample subjected to a chemical conversion treatment as a production lot different from that of Comparative Example 2 was also subjected to an additional analysis by Auger electron spectroscopy. This is referred to as Comparative Example 3.

[0091] In Comparative Example 3, the black color of the appearance is slightly reddish black and appears brown depending on the reflection angle of light, and it cannot be evaluated as a black color in a range that has lower reflectance and higher absorbance of visible light, which is called a pure black color. FIG. 22 shows the results of analysis by Auger electron spectroscopy of Comparative Example 3 in the same manner as described above. Based on FIG. 22, the film thickness was estimated in the same manner as above, and the oxide film thickness was approximately 2020 nm. That is, it can be seen that the film thickness of Comparative Example 3 was too thick compared to the film thickness distribution range of Examples of the present invention.

[0092] From the analysis results of Examples and Comparative Examples described above, it was found that, when the film thickness of the oxide film was greater than 2000 nm as in Comparative Example 1, there was a tendency for light reflection in which the brightness L* was small but the value of a* was high, resulting in a lighter reddish black color compared to the examples, and a reddish brown color depending on the reflection angle of light. On the other hand, it was found that when the film thickness of the oxide film was smaller than 100 nm as in Comparative Example 2, the brightness L* was too high (too bright), and the values of a* and b* were also high, resulting in the reflection of colored light. Compared to the examples, the appearance became a color closer to brown than black, and the appearance appeared brown also depending on the reflection angle of light. From Comparative Example 3, it was also found that when the film thickness of the oxide film was greater than 2000 nm, the black color in appearance became slightly reddish black.

[0093] From the results of the above comparative examples, it was found that the thickness of the oxide film is necessarily a film thickness greater than 100 nm and smaller than 2000 nm. From the results of the above examples, it was found that the thickness of the oxide film is preferably a film thickness of 320 nm or more and 1870 nm or less.

[0094] It can also be seen that when comparing the distribution of numerical range suitable for the film thickness for the lock pins made of the nickel-based stainless steel material shown in Example 1-16 to Example 1-21 and the distribution of numerical range suitable for the film thickness for the lock pins made of the manganese-based stainless steel material shown in Example 2-16 to Example 2-21, the numerical range suitable for the nickel-based material is shifted toward a slightly smaller film thickness than the manganese-based material. That is, when the stainless steel material of the lock pin 21, 31 is a stainless steel material containing 10% or more and 14% or less of nickel in percent by weight, it is preferable that the thickness of the oxide film on the surface of the lock pin 21, 31 is 320 nm or more and 1260 nm or less. Further, when the stainless steel material of the lock pin 21, 31 is a stainless steel material containing 13% or more and 17% or less of manganese in percent by weight, it is preferable that the thickness of the oxide film on the surface of the lock pin 21, 31 is 440 nm or more and 1870 nm or less.

[0095] In general, the formation of a black oxide film on a stainless steel material by chemical conversion treatment is related to the fact that the film thickness increases as the time of immersion in a chemical conversion treatment solution (a chromic acid solution, a caustic soda solution, or the like) for forming the oxide film increases. Therefore, as described above, if the suitable numerical range of the film thickness is known, the appropriate range of the time for immersion in the chemical conversion treatment solution can be easily inferred, and the above-described technical knowledge is advantageous technical information in terms of improving the efficiency of the manufacturing process.

[0096] Next, the film thickness of a test piece (a test piece having a shape of a slide fastener element) that was not a lock pin (the material is a ferritic stainless steel material (SUS430)) was also analyzed in the same manner, and the result are described with reference to FIGS. 23 to 28.

[0097] The ferritic stainless steel material is an alloy of iron and chromium and does not contain nickel, and thus has a disadvantage of being easily oxidized (easily rusted). On the other hand, the ferritic stainless steel material has an advantage that it is less susceptible to work hardening and easier to process than austenitic stainless steel material, making it an advantageous material to use for a component having a high processing rate such as a forging process like a fastener element. In this respect, although the circumstances are different from those of lock pins, where it is advantageous to use austenitic stainless steel material, in order to achieve a sense of unity in the black color for the entire slide fastener, it is important to comprehensively analyze and examine the tendency of blackening due to surface treatment of fastener element together with the tendency of blackening of the lock pin and the slider.

[0098] FIGS. 23 to 28 show the results of analyzing test pieces (test pieces having a shape of a slide fastener element) made of ferritic stainless steel material (SUS430), as in Example 3-1 to Example 3-15 shown in Table 3 above. For convenience, the example sample analyzed in FIG. 23 is referred to as Example 3-16, the example sample analyzed in FIG. 24 is referred to as Example 3-17, the example sample analyzed in FIG. 25 is referred to as Example 3-18, the example sample analyzed in FIG. 26 is referred to as Example 3-19, the example sample analyzed in FIG. 27 is referred to as Example 3-20, and the example sample analyzed in FIG. 28 is referred to as Example 3-21. Here, to explain in detail the relationship between the example samples of Example 3-1 to Example 3-15 shown in Table 3 and the example samples of Example 3-16 to Example 3-21 for which film thickness data was acquired by Auger electron spectroscopy, Example 3-1 to Example 3-5 in Table 3, and Example 3-16 (FIG. 23) and Example 3-17 (FIG. 24) for which film thickness data was acquired by Auger electron spectroscopy are example samples from a group subjected to the chemical conversion treatment as the same production lot. That is, when a small component such as the lock pin is subjected to a chemical conversion treatment, several hundreds of lock pins are subjected to the chemical conversion treatment all at once, and from the several hundreds of production lots that are subjected to the chemical conversion treatment all at once, seven lock pins, designated as Example 3-1, Example 3-2, Example 3-3, Example 3-4, and Example 3-5 which are shown in Table 3, and Example 3-16 (FIG. 23) and Example 3-17 (FIG. 24) for which the film thickness data was acquired by Auger electron spectroscopy, were randomly sampled for the purpose of acquiring measurement data.

[0099] Similarly, seven lock pins, designated as Example 3-6, Example 3-7, Example 3-8, Example 3-9, and Example 3-10 which are shown in Table 3, and Example 3-18 (FIG. 25) and Example 3-19 (FIG. 26) for which the film thickness data was acquired by Auger electron spectroscopy, belong to a group subjected to the chemical conversion treatment as the same production lot. Similarly, seven lock pins, designated as Example 3-11, Example 3-12, Example 3-13, Example 3-14, and Example 3-15 which are shown in Table 3, and Example 3-20 (FIG. 27) and Example 3-21 (FIG. 28) for which the film thickness data was acquired by Auger electron spectroscopy, belong to a group subjected to the chemical conversion treatment as the same production lot.

[0100] The definition of the thickness of the oxide film read from the measurement data in FIGS. 23 to 28 is the same as the method described with reference to FIG. 6. That is, in FIG. 23, the maximum value of the amount of oxygen in the vicinity of the surface formed in the sample is about 4300 on the vertical axis (Intensity), and the depth at which 50% of this value, 2150, is 1010 nm, is taken as the thickness of the oxide film.

[0101] That is, the thickness of the oxide film of Example 3-16 is 1010 nm.

[0102] Similarly, for the film thickness of the oxide film, the thickness of the oxide film of Example 3-17 shown in FIG. 24 is 1070 nm. The thickness of the oxide film of Example 3-18 shown in FIG. 25 is 1620 nm. The thickness of the oxide film of Example 3-19 shown in FIG. 26 is 1470 nm. The thickness of the oxide film of Example 3-20 shown in FIG. 27 is 2190 nm. A thickness of the oxide film of Example 3-21 shown in FIG. 28 is 2500 nm or more, which is beyond the range that can be measurable by the device, so the film thickness cannot be obtained by the same estimation method as described above, but it can be inferred that the thickness is about 2600 nm or more and 2800 nm or less. Therefore, the intermediate value thereof is taken, and 2700 nm is set as the estimated value of the film thickness.

[0103] The distribution range of the thickness of the oxide film of the six example samples, Example 3-16 to Example 3-21, is 1010 nm or more and 2700 nm or less.

[0104] Here, the shape of the fastener element is roughly a hexahedron having parallel planes facing each other, and the planes are likely to overlap with each other during the surface treatment with the chemical solution. Since the coloring treatment liquid does not easily flow through the overlapping surfaces, the growth of the film thickness on the overlapping surfaces is delayed. On the other hand, since the shape of the lock pin is not such a hexahedral shape, the coloring treatment liquid flows well over the entire surface of the lock pin. Therefore, in order to perform uniform coloring (chemical conversion treatment) on the fastener element, it is necessary to make the treatment time longer than the treatment time for the lock pin, and as a result, the oxide film formed on the surface tends to be thick. On the other hand, since the growth of the film thickness on the surface of the lock pin proceeds almost uniformly as a whole, it can be colored uniformly in a short time. In addition, since the ferritic stainless steel material does not contain nickel, the ferritic stainless steel material is more easily oxidized than the austenitic stainless steel material, and a growth rate of the film thickness tends to increase with the surface treatment. Due to such circumstances, the oxide film thickness of the fastener element made of the ferritic stainless steel material tends to be thicker than the oxide film thickness of the lock pin made of the austenitic stainless steel material. In this respect, although the surface treatment of the fastener element is different from the surface treatment of the lock pin, in order to achieve a sense of unity in the black color for the entire slide fastener, it is important to comprehensively analyze and examine the tendency of blackening due to surface treatment of fastener element together with the tendency of blackening of the lock pin and the slider.

[0105] From the results of FIGS. 23 to 28 above and the color measurement data shown in Table 3, it was found that when the thickness of the oxide film was set to 1010 nm or more and 2700 nm or less for the test piece (test piece having a shape of a slide fastener element) made of ferritic stainless steel material (SUS430), the black color becomes a black color in a range that has lower reflectance and higher absorbance of visible light than the same black color, which is called a pure black color. From this, it was found that by using a ferritic stainless steel material (SUS430) not only for the slider 20, 30 but also for the slide fastener element, with a film thickness in the above-described preferable numerical range, in a product with a concept that the entire product is pure black, a portion of the elements of the slide fastener no longer stands out and gives a different impression, and that the slide fastener as a whole can give a unified black impression.

[0106] According to the configuration of the slide fastener slider of the present invention, even if a user desires a product using the slide fastener to be black in color, which has low reflectance and high absorbance for visible light, the black color of the slide fastener slider does not cause a sense of discomfort in the entire product. In addition, the manufacturing cost is lower as compared with the case of blackening by plating. Further, the problem of adhesion of a colored layer, which occurs in the case of painting, is also improved.

[0107] The present invention is not limited only to the embodiments disclosed above, and it is also possible to appropriately use techniques recognized by a person of ordinary skill in the art as techniques substantially the same as the technical matters described in the embodiments of the present invention or techniques having the same effects as the technical matters, to use the techniques as alternative techniques, or to additionally add the techniques. Furthermore, it is also possible to recombine and implement characteristic configurations of the above embodiments.

[0108] In addition, throughout the present specification, portions described with reference signs in the drawings are described as constituent portions which are the minimum necessary in each embodiment of the present invention, and do not mean that the present invention is configured only from portions described with reference signs in the drawings.

[0109] In addition, the numerical values stated in the text of the present specification are transcribed, analyzed, and compared based on the numerical values of the table set forth in the present specification, and in a case where there is any discrepancy in the correspondence of the numerical values, the numerical values entered in the tables are presumed to be more accurate, in principle.

Claims

1. A slide fastener slider, comprising:a slider body;a puller; anda lock pin,wherein the lock pin is made of a stainless steel material,wherein a black oxide film is formed on a surface of the lock pin, andwherein the surface of the lock pin has brightness L* satisfying 31.70≤L*≤35.90, and a* of a value satisfying −0.708≤a*≤1.929, the brightness L* and the a* of the value according to definitions in a CIELAB color space defined in JIS Z8781-4 (2013).

2. The slide fastener slider according to claim 1,wherein the surface of the lock pin has b* of a value satisfying −2.428≤b*≤0.466, the b* of the value according to a definition in the CIELAB color space defined in JIS Z8781-4 (2013).

3. The slide fastener slider according to claim 1,wherein the stainless steel material for the lock pin is an austenitic stainless steel material containing 10 wt % to 14 wt % of nickel, andwherein the surface of the lock pin has the brightness L* satisfying 31.70≤L*≤34.16, the a* of the value satisfying 0.369≤a*≤1.736, and b* of a value satisfying −2.428≤b*≤0.466, the brightness L*, the a* of the value and the b* of the value according to definitions in the CIELAB color space defined in JIS Z8781-4 (2013).

4. The slide fastener slider according to claim 1,wherein the stainless steel material for the lock pin is an austenitic stainless steel material containing 13 wt % to 17 wt % of manganese, andwherein the surface of the lock pin has the brightness L* satisfying 33.04≤L*≤35.90, the a* of the value satisfying −0.708≤a*≤1.929, and b* of a value satisfying −2.388≤b*≤−1.495, the brightness L*, the a* of the value and the b* of the value according to definitions in the CIELAB color space defined in JIS Z8781-4 (2013).

5. The slide fastener slider according to claim 1,wherein the slider body is black, andwherein according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013),a difference ΔL* between brightness L* of the slider body and brightness L* of the lock pin satisfies ΔL*≤8.54, anda difference Δa* between a* of a value of the slider body and a* of a value of the lock pin satisfies 0.03≤Δa*≤2.67.

6. The slide fastener slider according to claim 3,wherein the slider body is black, andwherein according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013),a difference ΔL* between brightness L* of the slider body and brightness L* of the lock pin satisfies ΔL*≤6.79, anda difference Δa* between a* of a value of the slider body and a* of a value of the lock pin satisfies 1.11≤Δa*≤2.47.

7. The slide fastener slider according to claim 4,wherein the slider body is black, andwherein according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013),a difference ΔL* between brightness L* of the slider body and brightness L* of the lock pin satisfies ΔL*≤8.54, anda difference Δa* between a* of a value of the slider body and a* of a value of the lock pin satisfies 0.03≤Δa*≤2.67.

8. A slide fastener comprising:the slide fastener slider according to claim 1,wherein an element of the slide fastener is made of a ferritic stainless steel material, and the element has brightness L* satisfying 29.67≤L*≤36.24, a* of a value satisfying −0.63≤a*≤0.76, and b* of a value satisfying 0.42≤b*≤1.22, the brightness L*, the a* of the value and the b* of the value according to definitions in the CIELAB color space defined in JIS Z8781-4 (2013).

9. The slide fastener according to claim 8:wherein the slider body is black, andwherein according to the definitions in the CIELAB color space defined in JIS Z8781-4 (2013), a difference ΔL* between the brightness L* of the element and brightness L* of the slider body satisfies ΔL*≤8.94, and a difference Δa* between values of a* thereof satisfies 0.11≤Δa*≤1.49.

10. The slide fastener slider according to claim 1,wherein the oxide film on the surface of the lock pin has a thickness of 320 nm or more and 1870 nm or less.

11. The slide fastener slider according to claim 1,wherein the stainless steel material for the lock pin is an austenitic stainless steel material containing 10 wt % or more and 14 wt % or less of nickel, and a thickness of the oxide film on the surface of the lock pin is 320 nm or more and 1260 nm or less.

12. The slide fastener slider according to claim 1,wherein the stainless steel material for the lock pin is an austenitic stainless steel material containing 13 wt % or more and 17 wt % or less of manganese, and a thickness of the oxide film on the surface of the lock pin is 440 nm or more and 1870 nm or less.

13. The slide fastener according to claim 8,wherein a thickness of an oxide film on the element of the slide fastener is 1010 nm or more and 2700 nm or less.

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