JP3197413U - Metallic fastener member having lemon gold color and fastener having the same - Google Patents

Abstract

The present invention provides a metal fastener member having a lemon gold color and having practical strength, workability, and stress corrosion resistance. In a CIELAB color space defined by JIS Z8781-4 (2013), a copper alloy having a composition containing 23 to 30% by mass of Zn and the balance of Cu and inevitable impurities is used as a base material. It is a metal fastener member having a surface color satisfying .7≰a * ≰−3.0 and 20≰b * ≰32. More preferably, the arithmetic average roughness Ra of at least a part of the surface of the base material is 0.1 μm or less, and the Zn content is 23 to 27 mass%. [Selection] Figure 1

Description

  The present invention relates to a metal fastener member. The present invention also relates to a fastener provided with the metal fastener member.

  The slide fastener is a well-known component as an opening / closing tool for various articles. It is known that elements and fasteners that are meshing parts of a slide fastener can be manufactured using a metal as a material, and in particular, those using a copper alloy as a material are frequently used. Conventional characteristics required for a copper alloy fastener member include high whiteness, excellent smoothness, high plating properties, and high castability. As copper alloy materials for fasteners, copper-nickel-zinc alloys such as iron white and copper-zinc alloys such as red and brass are well known, and various improvement proposals centered on these copper alloys. Has been made.

  In JP-A-10-18046 (Patent Document 1), in order to provide a method for producing a slide fastener having a high-gloss copper or copper alloy working tooth excellent in smoothness of the outer surface or a chain thereof, Cu: Hydrogen peroxide, sulfuric acid, phosphoric acid, surfactant for elements made of copper or copper alloy having composition of 60-100%, Zn: 0-35%, Ni: 0-15%, and inevitable impurities And soaking in an acid treatment solution containing an aliphatic alcohol and smoothing the outer surface of the element by acid treatment.

  In Japanese Patent Application Laid-Open No. 2003-183750 (Patent Document 2), for the purpose of providing a copper alloy for a slide fastener having excellent whiteness, no nickel allergy problem, and excellent in continuous castability and casting quality, a general formula is used. : CuaZnbMnc (where a, b, c are mass%, a is the balance, 10 ≦ b ≦ 20, 8 ≦ c ≦ 15, may contain inevitable elements) ing.

  In Japanese Patent Laid-Open No. 2003-180410 (Patent Document 3), the surface whiteness, the decorativeness on appearance, and the gloss are improved by performing a combination of electrolytic plating and electroless plating on a copper alloy element member. I am trying. Examples of copper alloys to be used include brass, brass, and general formula: CuaZnbMncMdXe (where M is at least one element selected from Al and Sn, X is at least one element selected from Si, Ti, and Cr, a, b , C, d and e are mass%, a is the balance, 0 ≦ b ≦ 22, 7 ≦ c ≦ 20, 0 ≦ d ≦ 5, 0 ≦ e ≦ 0.3, and may contain inevitable elements.) The alloy represented by is described.

JP-A-10-18046 JP 2003-183750 A JP 2003-180410 A

  In recent years, with the diversification of user preferences, the characteristics required of metal fastener members are also diversifying, and problems have arisen that cannot be dealt with by conventionally studied materials. For example, until now most of the ornaments such as rings and necklaces have a white color tone, so a material with high whiteness has been desired. Needs are also increasing. For example, a gold-colored accessory fitting is often used for recent high-class bags, and a lemon-gold accessory fitting is sometimes attached from the viewpoint that the gorgeousness can be emphasized among the gold colors. At this time, the use of metal fasteners of the same color as the attached metal fittings can also be used for fasteners used in the same cage, so the need for a metal fastener member with a lemon gold color is gradually increasing. It has increased.

  Although the color can be controlled by adjusting the color of the plating film, in a slide fastener, the members are rubbed when the fastener is operated, and therefore the plating film may be peeled off. Since the color of the material is exposed when the plating film is peeled off, there is a problem that the design is impaired. Also, if the material is subject to discoloration, it will not be possible to maintain aesthetics due to discoloration over time. Some plating solutions can be expensive. On the other hand, from the viewpoint of practicality, it is desired not only to have a desired color but also to have strength, workability, and stress corrosion resistance that are highly practical as a fastener member.

  Brass (for example, Cu: 65% by mass, Zn: 35% by mass) is an example of an existing copper alloy having a color similar to lemon gold, but brass is easy to work and harden, although the material itself is inexpensive. There are difficulties. For this reason, the tool life used in the manufacturing process of the fastener element such as wire drawing, rolling, and planting is shortened, and the processing cost is increased. In addition, brass has a disadvantage of low stress corrosion resistance due to a large amount of zinc. Furthermore, the color tone of brass is not strictly a lemon gold color, and is different from the gorgeous color tone desired by the user.

  The present invention was created based on the above circumstances, and provides a metal fastener member having a specific color of lemon gold and having strength, workability and stress corrosion resistance that can withstand practicality. This is one of the issues. Moreover, this invention makes it another subject to provide the fastener provided with such metal fastener members.

  The inventor has intensively studied to solve the above-mentioned problems. By using a copper alloy containing Zn in an amount of 23 to 30% by mass, a bright lemon gold color can be obtained, and the practicality as a fastener member can be obtained. It has been found that high strength, workability and stress corrosion resistance can be obtained. The present invention has been completed based on this knowledge.

In the first aspect of the present invention, CIELAB specified in JIS Z8781-4 (2013) is based on a copper alloy having a composition containing 23 to 30% by mass of Zn and the balance of Cu and inevitable impurities. It is a metal fastener member having a surface color satisfying −5.7 ≦ a ^* ≦ −3.0 and 20 ≦ b ^* ≦ 32 in the color space.

In one embodiment of the metal fastener member according to the present invention, −5.5 ≦ a ^* ≦ −4.5, 26 ≦ b ^* ≦ in the CIELAB color space defined by JIS Z8781-4 (2013). 32 having a surface color.

  In another embodiment of the metal fastener member according to the present invention, the arithmetic average roughness Ra of the surface of at least a part of the base material is 0.1 μm or less.

  In still another embodiment of the metal fastener member according to the present invention, the base material is a copper alloy containing 23 to 27% by mass of Zn and the balance of Cu and inevitable impurities.

  In still another embodiment of the metal fastener member according to the present invention, the metal fastener member is an element for a slide fastener.

  In another aspect, the present invention is a slide fastener including the metal fastener member according to the present invention.

  The metal fastener member according to the present invention exhibits a lemon gold color in which the base material itself is excellent in aesthetics. For this reason, since the cut surface after performing a cutting process has the same color as a non-cut surface, designability is not impaired by a cutting process. Moreover, it is not necessary to perform a plating process that may impair the design properties due to peeling. Since the lemon gold color can be expressed with a relatively inexpensive material mainly composed of Cu without plating, a high-quality fastener member can be provided to the user at an affordable price. Furthermore, the metal fastener member according to the present invention has excellent strength, workability, and stress corrosion resistance, and can be said to be extremely practical in terms of productivity and service life.

It is a schematic diagram when a slide fastener is seen from the front. It is a figure explaining how to attach a lower stopper, an upper stopper, and an element to a fastener tape.

(1. Composition)
In one embodiment, the metal fastener member according to the present invention contains, as a base material, a copper alloy containing Zn in an amount of 23 to 30% by mass and the balance of Cu and inevitable impurities. Zn changes the color tone of the copper alloy to yellow when added to copper. Furthermore, Zn has the effect of improving the mechanical properties and work hardening properties of the alloy by solid solution strengthening, the deoxidation effect in melt casting, and the effect of reducing the price of the fastener member. By increasing the Zn content, the cost can be reduced and high strength can be obtained. Moreover, the advantage that the oxidation resistance and castability of the molten metal are improved is also obtained. However, Zn has a characteristic that cold workability is impaired when excessively added.

  In the present invention, the lower limit of the Zn content is set to 23% by mass. When the Zn content is less than 23% by mass, it becomes difficult to obtain a target lemon gold color and an excellent strength is obtained. It is because it is hard to be done. From the viewpoint of obtaining a bright lemon gold color, the Zn content is preferably 24% by mass or more, and more preferably 25% by mass or more. In addition, the upper limit of the Zn content is set to 30% by mass. When the Zn content exceeds 30% by mass, it is difficult to obtain good castability and workability. Furthermore, excellent stress corrosion resistance is achieved. This is because it becomes difficult to obtain. From the viewpoint of obtaining a metal fastener member excellent in castability, workability and stress corrosion resistance, the Zn content is preferably 29% by mass or less, more preferably 28% by mass or less, and still more preferably. 27% by mass or less. The upper limit of the Zn content is 30% by mass within a range where a bright lemon gold color is obtained, which is also appropriate from the viewpoint of color tone.

  Inevitable impurities are present in the raw material or are inevitably mixed in the manufacturing process and are essentially unnecessary, but they are acceptable because they are very small and do not affect the characteristics. It is an impurity. In the present invention, the content of each impurity element allowed as an inevitable impurity is generally 0.1% by mass or less, preferably 0.05% by mass or less.

(2. Color tone)
In principle, the color tone of the copper alloy is determined by the composition. According to the study results of the present inventors, by using a copper alloy having the above composition as a base material, in the CIELAB color space defined by JIS Z8781-4 (2013), −5.7 ≦ a ^* ≦ −. A surface color satisfying 3.0 and 20 ≦ b ^* ≦ 32 is obtained. Note that a ^* is a value indicating a magenta-green color tone (+ is near magenta,-is green), and b ^* is a yellow-blue color tone (+ is yellow,-is blue). Value. From the viewpoint of obtaining a gorgeous lemon gold color, in the CIELAB color space defined in JIS Z8781-4 (2013), −5.5 ≦ a ^* ≦ −4.5 and 26 ≦ b ^* ≦ 32 must be satisfied. Is preferable, and it is more preferable to satisfy −5.4 ≦ a ^* ≦ −5.0 and 27 ≦ b ^* ≦ 30.

(3. Surface roughness)
The color tone of the copper alloy is basically determined by the composition, but the surface color is affected by the surface roughness. As the surface of the base material becomes smooth by polishing, a ^* tends to change in a small direction (green direction), and b ^* tends to change in a large direction (yellow direction). In order to obtain a fastener member, it is desirable to perform an appropriate smoothing process after adjusting the composition.

  From the viewpoint of obtaining a gorgeous lemon gold color, the arithmetic average roughness Ra of the base material surface of the metal fastener member is preferably 0.1 μm or less. Also, the surface roughness of the metal fastener member is reduced and smoothed so that the metal fastener member is smooth to the touch, and when used as a slide fastener member, the sliding performance of the slider is also improved. . It also has the effect of improving luster and aesthetics. Therefore, the arithmetic average roughness Ra of the base material surface of the metal fastener member is more preferably 0.08 μm or less, and still more preferably 0.06 μm or less. However, if the surface of the base material is excessively smooth, unevenness of the smooth surface is likely to occur. Therefore, the arithmetic average roughness Ra of the surface of the base material of the metal fastener member is preferably 0.02 μm or more, and 0.04 μm or more. It is more preferable that In the present invention, the arithmetic average roughness Ra of the surface of the base material is measured with a contact type roughness meter in accordance with JIS B0601 (2001). Note that the arithmetic average roughness Ra of the base material surface is a value in a state before the rust prevention treatment or clear coating is applied, and does not affect the roughness of the base material surface when these treatments are performed. Measured after removal.

(4. Manufacturing method)
The suitable manufacturing method of the metal fastener member based on this invention is demonstrated. Although there is no special restriction | limiting in the shape of a metal fastener member, it demonstrates taking the example of the fastener element which is a typical use. First, copper and zinc are blended and dissolved so as to have a predetermined component composition, and then a wire is produced by continuous casting. After the unevenness on the surface of the obtained wire is removed by a method such as peeling, wire drawing is performed. Subsequently, after recovering workability by annealing, a continuous deformed wire having a substantially Y-shaped cross section is produced while imparting work strain by cold rolling. In this process, work hardening progresses according to the alloy composition, and the material strength increases. Thereafter, various kinds of cold working such as cutting, pressing, bending, and caulking are performed to plant the fastener element on the fastener tape. Various surface treatments may be applied to the fastener element before and / or after planting on the fastener tape.

  Examples of the metal fastener member include an upper stopper, a lower stopper, a puller, and a slider in addition to the fastener element. Further, in the present invention, the metal fastener member includes a Y-shaped continuous deformed wire in addition to those in the form of the final part such as an element.

(surface treatment)
The metal fastener member according to the present invention can be subjected to various surface treatments as necessary. For example, smoothing treatment, rust prevention treatment, clear coating treatment, and plating treatment can be performed.

As described above, the smoothing treatment is desirable from the viewpoint of obtaining a gorgeous lemon gold color. Typically, the surface of the fastener member before the smoothing treatment is −4.0 ≦ a ^* ≦ −3.0, 20 ≦ b ^* ≦ 23 in the CIELAB color space defined by JIS Z8781-4 (2013). However, after the smoothing process, the surface color can be changed to, for example, −5.5 ≦ a ^* ≦ −4.5 and 26 ≦ b ^* ≦ 32.

  Further, in the process of manufacturing the fastener member, by performing machining such as cutting, punching, and die, uneven cutting traces remain on the outer surface, which can be removed by smoothing. There is no limitation on the method of the smoothing treatment, and one or two or more of mechanical polishing, electrolytic polishing, chemical polishing, etc. may be combined as appropriate, but chemical polishing treatment is performed because it is simple and inexpensive. It is preferable to implement. In the chemical polishing treatment, for example, a chemical polishing liquid containing hydrogen peroxide and sulfuric acid can be used. Before and after the chemical polishing treatment, degreasing and / or pickling may be appropriately performed, and mechanical polishing such as buffing is preferably performed in advance for the purpose of facilitating burr removal.

  A suitable chemical polishing treatment method is a method in which a metal fastener member is immersed in an acid treatment solution containing hydrogen peroxide, sulfuric acid, phosphoric acid, a surfactant and an aliphatic alcohol, and then washed and dried. . In particular, a metal fastener member such as a slide fastener element is directly subjected to hydrogen peroxide: 50 to 250 g / L, sulfuric acid: 10 to 150 g / L, phosphoric acid: 0.5 to 5 g / L without going through a degreasing process. The method of immersing in the acid treatment liquid which consists of acidic aqueous solution containing surfactant: 0.01-2g / L and aliphatic alcohol: 1-100g / L is more preferable. According to this method, the smoothing treatment can be performed in a very short time by a single step of immersing in the acid treatment solution. The method is described in detail in Japanese Patent Application Laid-Open No. 10-18046, the entire text of which is incorporated herein.

  After the smoothing treatment, it is preferable to further carry out a rust prevention treatment (rust prevention step + water washing step + drying step). Further, after the rust prevention treatment or without the rust prevention treatment, a clear coating treatment (painting step + drying step) and a plating treatment can be further performed to improve the corrosion resistance, weather resistance, and the like.

  The rust prevention treatment is a process for preventing re-oxide formation on the surface of the metal fastener member smoothed by the acid treatment, and improving the adhesion of the coating film when performing clear coating or plating treatment later. . Rust prevention treatment is not necessary when the next process such as clear coating or plating treatment is performed immediately after the smoothing treatment, and even when other oxide treatments do not cause a slight oxide formation. It can be omitted.

  The rust-preventing step can be performed by dipping or spraying using a known benzotriazole-based aqueous solution, phosphate ester-based aqueous solution, or other rust-preventing solution. In order to improve the wettability of the metal fastener member, a surfactant may be added. The water washing step after the rust prevention step can be omitted if the rust inhibitor does not adversely affect the fastener tape. The drying step is preferably performed at a temperature of 150 ° C. or less that does not affect the dyeing fastness of the fastener tape by hot air or other heat source.

  By the clear coating process, the corrosion resistance of the metal fastener member can be increased. The clear coating treatment can be performed, for example, by applying a clear paint to the surface of the metal fastener member by a roll coater or other methods and then drying the coating film.

  In the metal fastener member according to the present invention, since the base material itself shows a lemon gold color, the plating process is not necessary for utilizing the color of the base material, but the plating process is performed for the purpose of improving the corrosion resistance and decorating. In addition to the electroplating method (electroless plating is preferably performed before electroplating), it does not preclude the use of various methods such as vacuum plating, dry plating such as sputtering and ion plating. .

When the plating treatment is performed in the same color as the base material, there is an advantage that the design property can be maintained even after the plating film is peeled off. When plating with the same color, the plating film preferably satisfies −5.7 ≦ a ^* ≦ −3.0 and 20 ≦ b ^* ≦ 32 in the CIELAB color space defined in JIS Z8781-4 (2013). Further, it is more preferable that the plating film has a ^* and b ^* within ± 2 with respect to a ^* and b ^{* of the} base material, respectively, and the plating film has a ^* and b ^* within ± 1 respectively. Is even more preferred. The same color plating is possible by making the composition of the plating film substantially the same as the composition of the base material.

  As a final step, waxing may be applied to reduce sliding resistance. This step may be omitted if the sliding resistance is sufficiently light.

(Slide fastener)
An example of a slide fastener provided with a metal fastener member (element, upper stopper and lower stopper) according to the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic diagram of a slide fastener. As shown in FIG. 1, a slide fastener has a pair of fastener tapes 1 having a core portion 2 formed on one side end side and a predetermined portion on the core portion 2 of the fastener tape 1. A pair of elements facing each other, with the element 3 being caulked and fixed (attached) at intervals, the upper stopper 4 and the lower stopper 5 being caulked and fixed to the core 2 of the fastener tape 1 at the upper and lower ends of the element 3 3 is provided with a slider 6 that is slidable in the vertical direction to engage and disengage the element 3. A state in which the element 3 is attached to the core portion 2 of one fastener tape 1 is called a slide fastener stringer, and the element 3 attached to the core portion 2 of the pair of fastener tapes 1 is engaged. What is present is called a slide fastener chain 7.

  In addition, the slider 6 shown in FIG. 1 is not shown in the figure, but a long body made of a plate-like body having a rectangular cross section is subjected to press processing in multiple stages, cut at predetermined intervals, and a slider body is produced. Furthermore, a spring and a handle are mounted as necessary. Further, the puller is also punched out from the plate-like body having a rectangular cross section for each predetermined shape, and is caulked and fixed to the slider body. The bottom stop 5 may be a break-and-fit insert composed of a butterfly stick, a box stick, and a box, and the pair of slide fastener chains can be separated by a slider opening operation. .

  FIG. 2 is a view showing a manufacturing method of the element 3, the upper stopper 4 and the lower stopper 5 of the slide fastener shown in FIG. 1 and how to attach the fastener tape 1 to the core portion 2. As shown in the figure, the element 3 is formed by cutting a deformed wire 8 having a substantially Y-shaped cross section for each predetermined dimension, and press-molding this to form an engaging head 9, and then the fastener tape 1. It is attached by caulking both leg portions 10 to the core portion 2.

  The upper stopper 4 is formed by cutting a rectangular wire 11 (rectangular wire) having a rectangular cross section into a predetermined dimension, forming it into a substantially U-shaped cross section by bending, and then caulking the core portion 2 of the fastener tape 1. Is attached. The lower stopper 5 is mounted by cutting a deformed wire 12 having a substantially X-shaped cross section for each predetermined size, and then caulking the core wire 2 of the fastener tape 1.

  In the figure, the element 3 and the upper and lower stoppers 4 and 5 are attached to the fastener tape 1 at the same time. However, in actuality, the element 3 is continuously attached to the fastener tape 1, and the fastener chain is first attached. The element 3 in the fastener attaching region of the fastener chain is removed, and a predetermined upper and lower stopper 4 or 5 is mounted in the vicinity of the element 3 in this region. Since manufacture and attachment are performed as described above, the elements and fasteners that are constituent members of the slide fastener need to be made of materials having excellent cold workability. In this respect, the metal fastener member according to the present invention is excellent in cold workability, and can be processed with a rolling reduction of 70% or more, for example, and thus is suitable as a material for elements and upper and lower stops.

  The slide fastener can be attached to various articles, and particularly functions as an opening / closing tool. The article to which the slide fastener is attached is not particularly limited, and examples thereof include daily necessaries such as clothing, bags, shoes, and miscellaneous goods, and industrial articles such as water storage tanks, fishing nets, and space suits.

  As mentioned above, although the embodiment at the time of applying the metal fastener member concerning this invention to the element for slide fasteners was described mainly, the metal fastener member concerning this invention is not necessarily limited to a slide fastener. It can also be applied as a member for snap fasteners and other metal fasteners.

  Examples of the present invention will be described below, but these are provided for better understanding of the present invention and its advantages, and are not intended to limit the present invention.

<Fabrication of fastener chain>
Using Cu (purity 99.99% by mass or more) and Zn (purity 99.9% by mass or more) as raw materials, these raw materials are blended so as to have each component composition according to the test numbers shown in Table 1. Then, a wire (round wire) having a perfect cross-sectional shape was produced by continuous casting. After removing the surface irregularities of the obtained wire using a peeling die, the wire was drawn to form a round wire. This was annealed, and then cold-rolled to give a working strain with a surface reduction rate of 40% to produce a continuous deformed wire (hereinafter referred to as “Y-bar”) having a substantially Y-shaped cross section. After that, after performing various cold working of cutting, pressing, bending and caulking to make the element shape of the size of “No. 3” defined in the YKK Corporation catalog “FASTENING Senka (issued in February 2009)”, This was attached to a polyester fastener tape to form a fastener stringer, and the opposing elements of a pair of fastener strigs were meshed to produce a fastener chain.

<Surface treatment>
The obtained fastener chain was buffed for deburring, and then immersed in an acid treatment solution at 30 ° C. for 2 minutes for chemical polishing. As the acid treatment liquid, polyoxyethylene oleyl ether as a surfactant is 1 g / L, hydrogen peroxide is 80 g / L, sulfuric acid is 20 g / L, phosphoric acid is 0.5 g / L, and methyl alcohol is 20 g / L. The contained acidic aqueous solution was used. Next, in order to facilitate washing and washing in the next step, the acid treatment liquid contained in the fastener tape was removed by vacuum dehydration. Thereafter, as a water washing step, water was strongly sprayed on the fastener chain, and then immediately vacuum dehydrated, followed by immersion in water and immediately vacuum dehydration. In order to sufficiently remove the acid treatment liquid contained in the fastener tape, the water washing step including spraying, dehydration, dipping, and dehydration was performed three times. Finally, clear coating was performed on the surface of the metal fastener member using a roll coater.

<Color tone test>
A color difference meter manufactured by Minolta Co., Ltd. for each surface treatment (element leg) of the element surface of the fastener chain in each stage after buffing, chemical polishing, and clear coating Using CR-300, a ^* and b ^* in the CIELAB color space defined by JIS Z8781-4 (2013) were determined under the conditions of 0 to 40 ° C. and 85% RH or less. A pulsed xenon lamp was used as the light source. The results are shown in Table 1.

<Surface roughness test>
Arithmetic mean roughness Ra at each surface treatment (element leg part) of the element surface of the fastener chain before and after chemical polishing was measured with a contact type roughness meter in accordance with JIS B0601 (2001). The measurement was performed four times for any two elements, and the average value was taken as the measurement value.

<Workability test>
A Y-bar made of a copper alloy having a composition corresponding to the test number is prepared in the same procedure as described above, and then a tensile test is performed by the metal material tensile test method of JIS Z 2241 (2011) to measure the tensile strength and elongation. did. The tensile test was performed 3 times, and the average value was taken as the measured value. The results are shown in Table 1.

<Stress corrosion cracking test>
The sample was exposed to ammonia according to the ammonia test method specified in JIS H3250 (2012). The test was conducted at room temperature for 50 minutes with a fastener chain installed at a position 50 mm away from the liquid surface in a desiccator containing ammonia water at a concentration of 15%. Thereafter, the pullout strength of the element was measured with respect to the fastener chain. The pull-out test uses an Instron type tensile tester to hold the meshing head of one element with a jig and pull it at a pulling speed of 300 mm / min until the element is pulled out from the fastener tape fixed to the clamp. This was done by measuring the strength. The tensile direction of the element was perpendicular to the longitudinal direction of the fastener tape and parallel to the surface of the fastener tape. The measurement result was an average value after 6 measurements.

<Discussion>
From Table 1, it can be seen that in Test No. 1 (Invention Example), an element having a predetermined lemon gold color was obtained, and the strength and workability withstanding practicality were obtained. It can also be seen that smoothing the element surface moved a ^* to the minus side and b ^* to the plus side, and a more gorgeous lemon gold color was obtained. In addition, the wire having the composition of test number 1 had a tensile strength higher than that of test numbers 2 and 3, but the elongation rate was comparable to these. For this reason, it can be understood that the element of Test No. 1, which is an invention example, can achieve both high strength and good workability. Furthermore, the element of Test No. 2 had a pullout strength that was reduced by about 50% after exposure to an ammonia atmosphere, whereas the element of Test No. 1 did not show a decrease in strength. From this, it can be seen that the element of test number 1, which is an invention example, is excellent in stress corrosion cracking resistance.

DESCRIPTION OF SYMBOLS 1 Fastener tape 2 Core part 3 Element 4 Upper stopper 5 Lower stopper 6 Slider 7 Slide fastener chain 8 Deformation line 9 of cross-sectional substantially Y shape Engagement head 10 Leg part 11 Rectangular line 12 Deformation of cross-section substantially X character line

Claims (6)

In a CIELAB color space defined in JIS Z8781-4 (2013), a copper alloy having a composition containing 23 to 30% by mass of Zn and the balance being Cu and inevitable impurities is used, and −5.7 ≦ a A metal fastener member having a surface color satisfying ^* ≦ −3.0 and 20 ≦ b ^* ≦ 32. The metal-made metal according to claim 1, having a surface color satisfying −5.5 ≦ a ^* ≦ −4.5 and 26 ≦ b ^* ≦ 32 in the CIELAB color space defined in JIS Z8781-4 (2013). Fastener member.   The metal fastener member according to claim 1 or 2, wherein an arithmetic average roughness Ra of at least a part of the surface of the base material is 0.1 µm or less.   The metal fastener member according to any one of claims 1 to 3, wherein the base material is a copper alloy containing Zn in an amount of 23 to 27 mass% with the balance being Cu and inevitable impurities.   It is an element for slide fasteners, The metal fastener member as described in any one of Claims 1-4.   A slide fastener provided with the metal fastener member as described in any one of Claims 1-5.

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