阅读说明：本技术 紧固件部件 (Fastener component ) 是由 枪野健太郎 长谷川格 于 2018-09-06 设计创作，主要内容包括：提供一种能够廉价地制造的黑色的金属制紧固件部件。紧固件部件具备：铜合金制的基体,其以30质量％以上43质量％以下的浓度含有锌；和黑色氧化铜覆膜,其覆盖该基体的至少一部分。(Provided is a ferrous metal fastener component which can be manufactured at low cost. The fastener member includes: a copper alloy substrate containing zinc at a concentration of 30 to 43 mass%; and a black copper oxide coating film covering at least a part of the substrate.)

1. A fastener member is provided with: a copper alloy substrate containing zinc at a concentration of 30 to 43 mass%; and a black copper oxide coating film covering at least a part of the substrate.

2. The fastener component of claim 1,

when the black copper oxide film is divided into a lower layer below the thickness center and an upper layer above the thickness center, the lower layer has a lower porosity than the upper layer.

3. The fastener component of claim 2,

the difference between the void ratio of the lower layer and the void ratio of the upper layer is 10% or more.

4. The fastener component of claim 2,

the difference between the void ratio of the lower layer and the void ratio of the upper layer is 20% or more.

5. The fastener component of any of claims 2 to 4,

the upper layer has a porosity of 14% or more.

6. The fastener component of claim 5,

the porosity of the upper layer is 20% or more.

7. The fastener component of any of claims 2 to 6,

the lower layer has a porosity of 12% or less.

8. The fastener component of claim 7,

the lower layer has a porosity of 8% or less.

9. The fastener component of any one of claims 1 to 8,

the black copper oxide film surface had a CIELAB color difference (Δ E ×) from the color coordinates (50,1, -3) in the CIELAB color space specified in JIS Z8781-4(2013)_ab) Color coordinates of 7 or less.

10. The fastener component of any one of claims 1 to 9,

the thickness of the black copper oxide film is 0.4 to 4.0 μm.

11. A fastener provided with the fastener member according to any one of claims 1 to 10.

12. An article provided with the fastener of claim 11.

Technical Field

The present invention relates to a fastener component based on a copper alloy. The present invention also relates to a fastener including a fastener member made of a copper alloy as a base.

Background

In some fastener products, there is a copper alloy slide fastener using a copper alloy containing zinc (hereinafter, also referred to as "Cu — Zn alloy") such as brass, red brass, or zinc white copper for components (for example, a row of elements as an engagement portion, a slider for controlling engagement and disengagement of the element row to open and close the slide fastener, and the like) (for example, japanese patent laid-open publication No. 2003-183750 and japanese patent laid-open publication No. 2002-285264). Zinc is an alloy element that is conventionally added to a copper alloy slide fastener because of the effect of increasing the strength, hardness, and uniform deformation of the alloy by solid solution.

On the other hand, a technique for blackening the surface of copper or a copper alloy is known. Jp 2000 a-248375 a describes a chemical conversion treatment method for forming a black coating having a matte black appearance and light-shielding properties by growing a velvet-like crystal coating of copper oxide. In the embodiment of this document, alkali degreasing, dezincification treatment, and blackening treatment (Ebonol treatment) are described as being performed on a cylindrical brass component.

In japanese patent laid-open publication No. 2004-292898, the following method is described: a low-reflection material is produced by anodizing a material made of copper or a material coated with copper on the surface in an aqueous sodium hydroxide solution to form a divalent copper oxide film.

In japanese patent application laid-open No. 11-189881, for the purpose of providing a novel composition and a treatment method effective for black-treating a brass surface, a black-treated composition is proposed, which is characterized by comprising:

(A) at least one selected from basic copper carbonate, copper hydroxide, copper (II) oxide, and tetraammine copper (II) salts represented by formula 1;

[Cu(NH₃)₄]X₂(wherein X is OH, Cl or NO)₃、NCS、Cu(I)Cl₂、1/2SO₄、HCO₃、1/2CO₃Monovalent anion) … formula 1

(B) At least one selected from ammonia water, ammonia gas, liquid ammonia, ammonium carbonate and ammonium bicarbonate; and

(C) as a result of the remaining part of the water,

the concentration of the (copper component and ammonia component) in the composition is within a range surrounded by each point of (0.2 wt%, 2 wt%), (0.2 wt%, 10 wt%), (1.5 wt%, 20 wt%), (2.5 wt%, 10 wt%), (1.5 wt%, 2 wt%).

In the embodiment of the invention of this document, there is described the cutting of a C3604 brass bar to a diameterThe parts obtained in the form of a 20mm sphere were subjected to a black treatment.

Japanese patent application laid-open No. 09-143753 describes a heat exchanger fin in which a copper oxide film is formed by chemical conversion on the surface of a copper plate by a black copper oxide method. Specifically, a copper oxide film having a thickness of 1 to 3 μm is formed on the surface of a copper plate by boiling an aqueous solution of 5% sodium hydroxide and 1% potassium persulfate at a temperature of 100 ℃ or higher for about 3 to 15 minutes.

JP-A-2003-510466 and JP-A-2010-229555 describe that crystalline copper (I) oxide (cuprous oxide, Cu) is formed on the surface of a copper or copper alloy member by an anodic oxidation method₂O) inorganic coating layer. In the examples, it is described that red copper is anodized to give an appearance of a tan, brown or dark black color.

Japanese patent application laid-open No. 2009 and 218368 discloses an invention aimed at providing a surface treatment method (surface blackening treatment method) for a printed wiring board, which is excellent in productivity, can reduce running cost, and is easy to handle and maintain. Specifically, there is described a method for surface treatment of copper by forming a copper oxide film mainly composed of copper oxide on the surface of copper by performing electrolytic anodic treatment in an alkaline aqueous solution containing copper oxide ions at a saturated concentration of 0.001 [ mol/l ] or more.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-183750

Patent document 2: japanese laid-open patent publication No. 2002-285264

Patent document 3: japanese patent laid-open No. 2000-248375

Patent document 4: japanese laid-open patent application No. 2004-292898

Patent document 5: japanese laid-open patent publication No. 11-189881

Patent document 6: japanese laid-open patent publication No. H09-143753

Patent document 7: japanese Kokai publication Hei-2003-510466

Patent document 8: japanese patent laid-open No. 2010-229555

Patent document 9: japanese laid-open patent publication No. 2009 and 218368

Disclosure of Invention

In recent years, the preference of users has been diversified, and metal fastener members having various color tones have been demanded. On the other hand, the demand for cost reduction by users is also becoming more stringent year by year, and it is desired to provide a metal fastener component having a desired color tone at low cost. Under such circumstances, it is considered advantageous to develop a technique for providing a black metal fastener member at low cost when the color tone change of the fastener member is expanded for the user.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a ferrous metal fastener component that can be manufactured at low cost in one embodiment. Another object of the present invention is to provide a fastener including such a metal fastener member in another embodiment.

As far as the present inventors know, there has been no prior art that provides an example in which a Cu — Zn alloy having a high zinc concentration, such as a zinc concentration of 30 mass% or more, is used as a base of a fastener member and the surface thereof is blackened. One of the reasons for this is that, in a Cu — Zn alloy, cold workability decreases as the zinc concentration increases.

However, zinc is less expensive than copper, and is therefore also excellent in terms of economy. Therefore, it is advantageous to use a Cu — Zn alloy in which the amount of zinc is intentionally increased for the purpose of reducing the cost, for the base. The present inventors have earnestly studied to overcome the above-mentioned drawbacks, and have found that a fastener member made of a black metal, which has not been obtained so far, can be obtained at a low cost by preferentially increasing the zinc concentration of the fastener member. The present invention has been completed based on the above technical ideas, and is exemplified below.

[1]

A fastener member is provided with: a copper alloy substrate containing zinc at a concentration of 30 to 43 mass%; and a black copper oxide coating film covering at least a part of the substrate.

[2]

In the fastener component according to [1], when the black copper oxide film is divided into a lower layer below the thickness center and an upper layer above the thickness center, the lower layer has a lower porosity than the upper layer.

「3」

The fastener component according to [2], wherein the difference between the void ratio of the lower layer and the void ratio of the upper layer is 10% or more.

[4]

The fastener component according to [2], wherein the difference between the void ratio of the lower layer and the void ratio of the upper layer is 20% or more.

[5]

The fastener component according to any one of [2] to [4], wherein the void ratio of the upper layer is 14% or more.

[6]

The fastener component according to [5], wherein the void ratio of the upper layer is 20% or more.

[7]

The fastener component according to any one of [2] to [6], wherein the lower layer has a void ratio of 12% or less.

[8]

The fastener component according to [7], wherein the lower layer has a void ratio of 8% or less.

[9]

In [1]]～[8]In the fastener component according to any one of the above items, the black copper oxide coating surface has a CIELAB color difference (Δ E) from color coordinates (50,1, -3) in a CIELAB color space defined in JIS Z8781-4(2013)_ab) Color coordinates of 7 or less.

[10]

The fastener member according to any one of [1] to [9], wherein the black copper oxide coating has a thickness of 0.4 to 4.0 μm.

[11]

A fastener comprising the fastener member according to any one of [1] to [10 ].

[12]

An article comprising the fastener according to [11 ].

Effects of the invention

According to one embodiment of the present invention, a ferrous metal fastener component can be provided at low cost.

Drawings

Fig. 1 is an example of a cross-sectional photograph of a black copper oxide coating including a boundary with a base for a fastener component (element) of example 1.

FIG. 2 is a schematic view of a zipper.

Fig. 3 is a view for explaining a mode of attaching a lower stopper, an upper stopper, and a fastener element to a fastener tape.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these embodiments.

<1. composition of matrix >

In one embodiment of the fastener member of the present invention, a base made of a copper alloy containing Zn at a concentration of 30 to 43 mass% is provided. In order to further improve the effect of reducing the material cost, the zinc concentration in the copper alloy is preferably 32 mass% or more, and more preferably 34 mass% or more. From the viewpoint of formability, the zinc concentration in the copper alloy is preferably 43 mass% or less, and more preferably 41 mass% or less.

The copper alloy constituting the base may contain a third element other than copper and zinc, for example, one or two or more elements selected from Sn, Al, Si, Fe, Ni, Mn, Mg, and Pb. Among them, Mn is preferably contained from the viewpoint of suppressing natural cracks. From the viewpoint of reducing the material cost, the total concentration of the third element other than copper and zinc is preferably 10 mass% or less, more preferably 5 mass% or less, and still more preferably 1 mass% or less. From the viewpoint of suppressing natural cracking, one or more of Sn, Al, Si, Fe, Ni, Mn, Mg, and Pb is preferably contained in a total amount of 0.1 mass% or more, and more preferably 0.3 mass% or more. In particular, Mn is preferably contained by 0.1 mass% or more, and more preferably 0.3 mass% or more. The copper alloy constituting the base may contain no element other than copper and zinc except inevitable impurities.

Accordingly, in one embodiment, the fastener member of the present invention includes a base made of a copper alloy containing Zn at a concentration of 30 mass% to 43 mass% with the remainder being composed of Cu and unavoidable impurities. In another embodiment, the fastener member of the present invention includes a base made of a copper alloy containing Zn at a concentration of 30 mass% to 43 mass%, and containing one or more of Sn, Al, Si, Fe, Ni, Mn, Mg, and Pb at 0.1 mass% to 10 mass% in total, with the remainder being made of Cu and unavoidable impurities.

The inevitable impurities are impurities which are present in the raw materials or inevitably mixed in the production process, and are originally unnecessary, but are contained in a trace amount without affecting the characteristics. In the present invention, the content of each impurity element allowed as an inevitable impurity is generally 0.1 mass% or less, and preferably 0.05 mass% or less.

< 2. Black copper oxide coating film >

In one embodiment of the fastener member of the present invention, the fastener member includes a black copper oxide coating film covering at least a part of the base. The black copper oxide coating may cover 60% or more, 80% or more, 95% or more, or all of the surface of the substrate.

When the surface of a Cu-Zn alloy having a high zinc concentration is blackened, attention is paid to a porosity which is not considered when the surface of a Cu-Zn alloy having a low zinc concentration is blackened. Controlling the porosity is effective in simultaneously achieving the blackness of the black copper oxide film and the adhesion of the black copper oxide film to the substrate. Specifically, when the black copper oxide film is divided into a lower layer on the lower side (substrate side) of the thickness center of the black copper oxide film and an upper layer on the upper side (surface side) of the thickness center, the porosity of the lower layer is preferably smaller than the porosity of the upper layer. The higher the porosity of the upper layer, the more reflection can be suppressed by light scattering, and the blackness is increased, while the lower the porosity, the more adhesion to the substrate is improved.

A method for measuring the void ratio of each of the upper layer and the lower layer of the black copper oxide film will be described. First, a cross section in a direction perpendicular to the surface of the black copper oxide film was cut out from a fastener member as an object of measurement, and the cross section including the boundary with the base of the black copper oxide film was observed at 50,000 times by a Scanning Electron Microscope (SEM). Fig. 1 shows an example of a cross-sectional photograph of a black copper oxide coating 120 including a boundary with a base 110, for a fastener component (element) of example 1 described later. In the SEM photograph, an approximate line a was drawn with respect to the boundary line between the base 110 and the black copper oxide film 120, and a direction perpendicular to the approximate line a was defined as a thickness direction of the black copper oxide film 120. The approximate straight line a can be obtained by drawing the coordinates of a plurality of points forming the boundary line on the orthogonal coordinate system and by the least square method.

Next, on the SEM photograph, 24 points of the thickness of the black copper oxide film 120 from the approximate straight line a were measured at intervals of 0.1 μm along the approximate straight line a, and the average thickness of the black copper oxide film 120 in the SEM photograph was obtained. Next, a straight line M of 1/2 having a distance equal to the average thickness from the approximate straight line a is drawn on the SEM photograph in parallel with the approximate straight line a, and the straight line M is set as the thickness center. The black copper oxide film portion on the outer side (front surface side) of the straight line M is an upper layer 120a of the black copper oxide film, and the black copper oxide film portion on the inner side (base body side) of the straight line M is a lower layer 120b of the black copper oxide film.

When the porosity of the lower layer is preferably smaller than the porosity of the upper layer, the difference between the porosity of the lower layer and the porosity of the upper layer is more preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more, in order to achieve both the blackness of the black copper oxide film and the adhesion between the black copper oxide film and the substrate. Although an upper limit is not set for the difference between the void ratio of the lower layer and the void ratio of the upper layer, it is generally 30% or less, typically 25% or less.

From the viewpoint of increasing the blackness of the black copper oxide film, the void ratio of the upper layer is preferably 14% or more, more preferably 18% or more, further preferably 20% or more, further preferably 22% or more, and most preferably 25% or more. However, from the viewpoint of preventing migration, the void ratio of the upper layer is preferably 40% or less, more preferably 35% or less, and still more preferably 30% or less.

From the viewpoint of improving the adhesion to the substrate, the porosity of the lower layer is preferably 12% or less, more preferably 10% or less, further preferably 8% or less, and most preferably 6% or less. Although the lower limit is not particularly set for the porosity of the lower layer, it is generally 2% or more, and typically 4% or more.

The void ratios of the upper layer and the lower layer were determined by the following procedures. On the SEM photograph, the highest luminance portion was assumed to be luminance 255, the lowest luminance portion was assumed to be luminance 0, and the image was binarized into black and white with the luminance 128 as a boundary. The upper and lower layers measure the number of pixels of black (voids) and white (mainly oxide) in the binarized image, and the ratio of the number of pixels of black to the total number of pixels (the total of the number of pixels of black and white) is obtained in the upper and lower layers, respectively, and is set as the void ratio of each of the upper and lower layers. The porosity was obtained using SEM photographs of arbitrary 10 or more fields, and the average value thereof was used as a measured value.

In one embodiment of the fastener component of the present invention, the black copper oxide coated surface can have a CIELAB color difference (Δ E ×) from color coordinates (50,1, -3) in a CIELAB color space specified in JIS Z8781-4(2013)_ab) Color coordinates of 7 or less, and the above CIELAB color difference (Δ E;)_ab) Color coordinates of 5 or less, and the above CIELAB color difference (Δ E;)_ab) Color coordinates of 3 or less.

The thickness of the black copper oxide coating is not particularly limited. However, from the viewpoint of darkening, it is preferably 0.4 μm or more, more preferably 0.7 μm or more, and still more preferably 1.0 μm or more. From the viewpoint of preventing migration, the thickness of the black copper oxide film is preferably 4.0 μm or less, more preferably 3.0 μm or less, and still more preferably 2.0 μm or less.

The thickness of the black copper oxide film was measured at 24 points at 0.1 μm intervals along the approximate straight line a by the method described above, and the average thickness of the black copper oxide film was determined for one field on average, and the average thickness was determined for any 10 or more fields, and the average value of 10 or more fields was defined as the measured value.

< 3. method for manufacturing fastener member >

The metal fastener member can be formed by appropriately combining cold working and melt casting, for example. A fastener element for a slide fastener, which is a typical use of a metal fastener member, will be described as an example. First, alloy components constituting a base material are prepared and melted, and then a wire rod is produced by continuous casting. The surface irregularities of the obtained wire rod are removed by a method such as peeling, and then wire drawing is performed. Subsequently, annealing is performed to recover the workability. Then, a continuous deformed line having a substantially Y-shaped cross section is produced by applying a working strain by cold rolling. In this process, work hardening progresses in accordance with the alloy composition, and the material strength increases. Then, various cold working such as cutting, punching, bending, and pressing is performed to implant the fastener elements into the fastener tape. The blackening treatment of the fastener member may be performed after the fastener member is formed into the final shape, or may be performed after the melt casting or during the cold working.

The blackening treatment of the fastener member can be performed by a chemical conversion treatment for forming a black copper oxide coating on the surface of the base of the fastener member. The chemical conversion treatment can be performed in the order of, for example, a degreasing step → a water washing step → a blackening step → a water washing step → a drying step. In the blackening step, a blackening solution containing an oxidizing agent and an alkaline agent can be used. Examples of the oxidizing agent include sodium hypochlorite, sodium chlorite, sodium chlorate, potassium hypochlorite, potassium chlorite, and potassium chlorate. One oxidizing agent may be used, or two or more oxidizing agents may be used simultaneously. Examples of the alkaline agent include sodium hydroxide and potassium hydroxide. One kind of the alkali agent may be used, or two or more kinds of the alkali agents may be used simultaneously. From the viewpoint of promoting the reaction, it is preferable that the blackening treatment liquid is heated at 40 to 100 ℃. When blackening the surface of a Cu-Zn alloy having a high zinc concentration, it is important to adjust the concentrations of an oxidizing agent and an alkaline agent in a blackening solution. By adjusting the concentrations of the oxidizing agent and the alkaline agent and controlling the oxidation rate and the dezincification rate, a film having a high porosity in the upper layer and a low porosity in the lower layer can be obtained, and a black copper oxide film having excellent adhesion can be formed.

While not intending to limit the invention by theory, it is believed that the effect on the oxidizing agent and the alkaline agent is as follows. The oxidizing agent dominates the rate of formation of the oxide, with higher concentrations giving higher rates of oxidation. The alkaline agent controls the dezincing rate in the depth direction, and the higher the concentration, the higher the dezincing rate. Therefore, when the concentration of the alkali agent is high, the porosity tends to be high for both the upper layer and the lower layer, but when the concentration of the oxidizing agent is high, the oxidation reaction proceeds before sufficient dezincification, and thus the porosity of the lower layer tends to be low. As a result, a black copper oxide film having a low porosity in the lower layer and a high porosity in the upper layer can be obtained. The concentration of the oxidizing agent and the concentration of the alkaline agent are also dependent on the type of the oxidizing agent and the type of the alkaline agent, and for example, the concentration of the oxidizing agent in the blackening solution is preferably adjusted within the range of 0.001 to 1 mol/L. The concentration of the alkali agent in the blackening solution is preferably adjusted to 1.0 to 5.0mol/L, and more preferably to 2.0 to 4.0 mol/L.

One or two or more other surface treatments may be further performed on the black copper oxide coating film. For example, a black paint such as black paint may be applied, and a surface treatment such as rust prevention may be performed.

< 4. fastener component >

The fastener member of the present invention is not limited, and a fastener element, a slider, an upper stopper and a lower stopper for a slide fastener can be exemplified. The use of the fastener member of the present invention is not limited to a slide fastener, and can be applied to other members for metal fasteners such as snap fasteners.

An example of a slide fastener including a fastener element, a slider, an upper stopper, and a lower stopper will be specifically described as a fastener member of the present invention based on the drawings. FIG. 2 is a schematic view of a zipper. As shown in fig. 2, the slide fastener includes: a pair of fastener tapes 1 having a core portion 2 formed along one side edge; fastener elements 3 which are press-fixed (attached) to the core portion 2 of the fastener tape 1 at predetermined intervals; an upper stopper 4 and a lower stopper 5 fixed to the core portion 2 of the fastener tape 1 are pressed against the upper end and the lower end of the element 3; and a slider 6 which is disposed between the pair of elements 3 facing each other and is slidable in the vertical direction to engage and disengage the elements 3. A member in which the element 3 is attached to the core portion 2 of one fastener tape 1 is referred to as a fastener stringer, and a member in which the elements 3 attached to the core portions 2 of the pair of fastener tapes 1 are engaged with each other is referred to as a fastener chain 7.

Further, the slider 6 shown in fig. 2 is formed as follows: a long body, not shown, made of a plate-like body having a rectangular cross section is subjected to press working in multiple stages and cut at predetermined intervals to produce a slider body, and further, a spring and a pull tab are attached as necessary. The pull tab is also a member that is punched out of a plate-like body having a rectangular cross section into a predetermined shape and is pressed and fixed to the slider body. The lower stopper 5 may be a separable bottom end stop including an insert pin, a box pin, and a receptacle, and the pair of fastener stringers may be separable by a separating operation of the slider.

Fig. 3 is a view showing a method of manufacturing the fastener element 3, the upper stopper 4, and the lower stopper 5 of the slide fastener shown in fig. 2, and a manner of attaching the fastener element to the core portion 2 of the fastener tape 1. As shown in the drawing, the fastener element 3 is attached by cutting a shaped wire 8 having a substantially Y-shaped cross section for each predetermined dimension, press-forming the wire to form an engagement head 9, and then pressing the two leg portions 10 against the core portion 2 of the fastener tape 1.

The upper stopper 4 is attached by cutting a rectangular wire 11 (flat wire) having a rectangular cross section into predetermined dimensions, bending the cut wire to form a substantially コ -shaped cross section, and pressing the wire against the core portion 2 of the fastener tape 1. The bottom stop 5 is attached by cutting a shaped line 12 having a substantially X-shaped cross section into predetermined dimensions and then pressing the cut line against the core portion 2 of the fastener tape 1.

In the drawings, the fastener elements 3, the upper stopper 4, and the lower stopper 5 are attached to the fastener tape 1 at the same time, but in practice, the fastener chain is manufactured by attaching the fastener elements 3 to the fastener tape 1 continuously, and then the predetermined upper stopper 4 or lower stopper 5 is attached near the fastener elements 3 at both ends of the fastener chain.

The slide fastener can be attached to various articles, and functions particularly as a shutter. The article to which the zipper is attached is not particularly limited, and examples thereof include daily necessities such as clothing, bags, boots, miscellaneous goods, and the like, and industrial goods such as a water tank, a fishing net, and space wear.

[ examples ] A method for producing a compound

The following examples of the present invention are provided for better understanding of the present invention and advantages thereof, and are not intended to limit the present invention.

<1. production of slide fastener chain

Using Cu (purity 99.99 mass% or more) and Zn (purity 99.9 mass% or more) as raw materials, these raw materials were blended and melted in a continuous casting apparatus so as to have respective alloy components corresponding to the test numbers described in table 1-1, and then continuous wire rods were produced by continuous casting. The obtained continuous wire rod was subjected to a wire drawing treatment. Next, annealing was performed at 500℃ for 1 hour in a reducing atmosphere containing oxygen of about 10 mass ppm to recover cold workability, and then a continuous deformed line having a substantially Y-shaped cross section was produced by cold rolling. Then, various cold working processes were performed such as cutting, pressing, bending, and pressing to obtain an element shape having a size of "5R" specified in catalog "FASTENING specialty of YKK corporation (2 month release 2009)", and then the element shape was attached to a polyester fastener tape to prepare a fastener stringer, and opposing elements of a pair of fastener stringers were engaged with each other to prepare a fastener chain.

< 2. blackening treatment >

The zipper chain produced as described above was subjected to alkali degreasing and water washing, and then subjected to a blackening step. The blackening step is performed by immersing the fastener chain in a blackening solution containing an oxidizing agent and an alkaline agent at 80 ℃ for five minutes while conveying the fastener chain by a roll-to-roll method. The blackening treatment was performed by changing the concentrations (mol/L) of the oxidizing agent and the alkaline agent in the blackening solution as shown in Table 1-1 in accordance with the test numbers shown in Table 1-1, thereby changing the void ratios of the upper layer and the lower layer of the copper oxide film. Then, the fastener chain is washed with water and dried while being conveyed by a roller-to-roller method.

< 3. color observation by visual observation >

After the blackening treatment, the color of the copper oxide film formed on the element surface of the fastener chain of each test example was visually observed. The results are shown in tables 1-2.

< 4. measurement of color coordinates of copper oxide coating film >

After the blackening treatment, any one of the fastener elements was detached from the fastener chain of each test example, and the color coordinates of the copper oxide film-coated surface of the fastener element in the CIELAB color space defined in JIS Z8781-4(2013) were measured by the method described above. CR-300 manufactured by Meinenda was used as a color difference meter. The measurement conditions are set to 0-40 ℃ and 85% RH or less. The light source used a pulsed xenon lamp. The measurement result was defined as CIELAB color difference (Δ E) from the color coordinates (50,1, -3) serving as the black reference_ab) And are shown in tables 1-2. In addition, a and b represent hues, a represents magenta-green hues (+ toward magenta and toward green), and b represents yellow-blue hues (+ toward yellow and toward blue). L represents lightness, and the higher the value is, the higher the gloss is.

< 5. thickness and void ratio of copper oxide coating film >

The thickness and porosity of the copper oxide film were measured for the fastener elements of the respective test examples in which the color coordinates were measured, by the methods described above. The element for exposing the cross section of the copper oxide film is cut by mechanical polishing or ion polishing (CP processing) after resin embedding. The cross-section of the copper oxide film was observed with a Scanning Electron Microscope (SEM) (model S-4800, manufactured by Hitachi high-tech Co., Ltd.) at a voltage of 2kV, a probe current of 15. mu.A, and a Working Distance (WD) of about 2 mm. The binarization process for void fraction determination was performed by the free software JTrim. The results are shown in tables 1-2.

< 6. adhesion of copper oxide coating film >

Adhesion to copper oxide coating film in a total area of 25mm²In the fastener chain after the blackening treatment, one surface of arbitrary ten continuous fastener elements was visually observed within the range of (1), and evaluated by the following criteria.

A: no peeled portion of the copper oxide film was observed.

B: peeling sites of the copper oxide film were observed at 1 to 10 points.

C: more than 10 peeling sites of the copper oxide film were observed.

[ tables 1-1]

[ tables 1-2]

< study >

Examples 1 and 2 and comparative example 1, in which the alloy components were close to each other, were compared. In comparative example 1, the concentration of the alkali agent was high, but the concentration of the oxidizing agent was too high, and the void ratios of both the upper layer and the lower layer were low. Therefore, although the adhesion is good, the blackening is insufficient. In contrast, in example 1, the concentration of the alkali agent was slightly low and the concentration of the oxidizing agent was slightly low, so that the low porosity of the lower layer and the high porosity of the upper layer could be achieved at the same time. As a result, a black copper oxide film having excellent adhesion was obtained. In example 2 in which the oxidizing agent concentration was lower, the lower layer had a higher porosity than the upper layer, and therefore the adhesion was reduced although the blackening was achieved.

Examples 3 and 4 having similar alloy components were compared. In example 3, the concentration of the alkali agent and the concentration of the oxidizing agent were properly balanced, and thus the lower layer had a low porosity and the upper layer had a high porosity. As a result, a blackened copper oxide film having excellent adhesion was obtained. In contrast, in example 4, since the concentration of the oxidizing agent was low and the porosity of the lower layer was increased, the adhesiveness was lowered although the black color was formed.

Comparative examples 2 and 3, which have similar alloy compositions, are compared. Both use a copper-zinc alloy having a zinc concentration as low as 15 mass%. Therefore, unlike examples 1, 2, 3, and 4 and comparative example 1, the form of the formed copper oxide does not affect the degree of black color and hardly changes the adhesion even if the porosity of the upper layer and the porosity of the lower layer are changed.

Description of the reference numerals

1 zipper tape

2 core part

3 zipper tooth

4 top stop

5 lower stop

6 puller

7 zipper chain

8-section approximately Y-shaped special-shaped line

9 fastening head

10 legs

11 rectangular wire

12-section approximately X-shaped special-shaped line

110 base body

120 black copper oxide film