TW201519871A - Nickel-copper alloy thin-film laminated film, electrode film for blood sugar sensor, strip for blood sugar sensor and device for blood sugar sensor - Google Patents

Abstract

The present invention provides a nickel-copper alloy thin-film laminated film that is inexpensive, has low surface electrical resistivity and chemical resistance, is excellent in storage stability, and can be used favorably as an electrode film for biosensors such as a blood sugar sensor. The film of the present invention is laminated with a nickel-copper alloy thin-film directly on at least one surface of a base material of the film or is laminated on the at least one surface of the base material of the film with other layers in between. The nickel-copper alloy thin-film has a nickel content between 40% to 95% by weight, and X-ray diffraction patterns of the nickel-copper alloy thin-film are demonstrated at three ranges: 43 DEG ≤ 2 [theta] ≤ 45 DEG, 49 DEG ≤ 2 [theta] ≤ 52 DEG, and 74 DEG ≤ 2 [theta] ≤ 77 DEG with a diffraction peak in at least one of three ranges.

Description

Nickel-copper alloy film laminated film, electrode film for blood sugar level sensor, blood glucose sensor strip and blood sugar level sensor device

The present invention relates to a nickel-copper alloy thin film laminated film, and more particularly, the present invention relates to a nickel-copper alloy thin film which is excellent in chemical resistance and long-term storage stability because of its high crystallinity. A nickel-copper alloy thin film laminated film suitable for use as an electrode for blood glucose sensor.

A blood glucose sensor is used to measure the value of a blood glucose level by measuring the blood glucose level several times a day by a diabetic patient or a person suspected of having diabetes. In the blood glucose level sensor, in order to detect the blood sugar level, a blood glucose sensor which is formed by patterning an electrode film having an expensive gold thin film is used (Patent Document 1). The reason is that the electrode film with a gold film laminated has a sense of The lower surface resistance value is important for the reliability of the detector, and is excellent in chemical resistance and long-term storage stability.

On the other hand, people with diabetes are more likely to be centered in Europe and the United States, but in recent years there has been an increase in the number of patients in the world such as Japan, China, and India. Therefore, the expectation of an inexpensive blood sugar level sensor increases, and as a result, the electrode film using an inexpensive electrode material is expected to become strong. However, in addition to the gold film, there is not much raw material that has gained market confidence in chemical resistance and long-term storage stability, and actually succeeded.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2011-50300

That is, in view of the above conventional problems, an object of the present invention is to provide a nickel-copper alloy thin film laminated film which is inexpensive, has a low surface resistance value, chemical resistance, and has excellent long-term storage stability and is suitable for use. It is used as an electrode film for a biosensor such as a blood sugar level sensor.

That is, the present invention includes the following constitution.

A nickel-copper alloy thin film laminated film which is formed by laminating a film of a nickel-copper alloy film directly on at least one side of a film substrate or via another layer, and the nickel content in the nickel-copper alloy film is 40% by weight. % or more and 95% by weight or less, the nickel-copper alloy film in the X-ray diffraction pattern is in the range of 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77° At least 1 range has a diffraction peak.

2. The nickel-copper alloy thin film laminated film according to the above 1, wherein the ratio of the number of oxygen atoms in the nickel-copper alloy thin film to the sum of the number of nickel atoms, the number of copper atoms, and the number of oxygen atoms is O/(Ni+Cu+O ) is 0.05 or less.

3. The nickel-copper alloy thin film laminated film according to the above 1 or 2, wherein the surface resistance value is 300 Ω/□ or less.

4. The nickel-copper alloy thin film laminated film according to the above 1 or 2, wherein an intermediate layer is provided between the film substrate and the nickel-copper alloy film, and the intermediate layer is a film of titanium or a nickel-titanium alloy.

5. The nickel-copper alloy thin film laminated film according to the above 4, wherein a total thickness of the nickel-copper alloy thin film and the intermediate layer is 10 nm or more and 400 nm or less.

6. The nickel-copper alloy thin film laminated film according to the above 1, 2 or 5, which satisfies the following requirements: (1) Cyclic voltammetry of ferrocyanide ions using silver or silver chloride as a reference electrode In the measurement, the potential between +0.2V and +0.5V shows the peak current of oxidation, the potential between 0V and +0.3V shows the peak current of reduction; (2) when the measurement of 2 cycles of voltammetry is performed The oxidation peak current and the reduction peak current measured by the second cyclic voltammetry show the oxidation peak current and the reduction peak current measured by the first cyclic voltammetry. The flow is substantially the same current.

An electrode film for a blood glucose sensor, which is obtained by patterning a nickel-copper alloy thin film which is a nickel-copper alloy thin film laminated film according to any one of the above 1 to 6.

A strip for a blood sugar level sensor, which is obtained by using the electrode film for a blood glucose sensor according to the above seventh aspect.

A blood glucose sensor device, which is obtained by using a blood glucose sensor strip as described in the above 8.

According to the present invention, a nickel-copper alloy thin film laminated film can be provided which is inexpensive, has a low surface resistance value, high chemical resistance, and excellent long-term storage stability, and can be suitably used as a biological sense of a blood sugar level sensor or the like. The electrode film for the detector is used. Further, the electrode film for a biosensor using a blood glucose sensor or the like of the nickel-copper alloy thin film laminated film of the present invention can stably take out the electric signal.

Fig. 1 is a view showing an X-ray diffraction pattern of a nickel-copper alloy thin film laminated film of Example 1.

Fig. 2 is a graph showing the results of in-depth analysis by X-ray photoelectron spectroscopy of the nickel-copper alloy thin film laminated film of Example 1.

Figure 3 is a cyclic voltammogram of the cyclic voltammetry measurement of the nickel-copper alloy thin film laminated film of Example 1. Voltammogram).

The nickel-copper alloy thin film laminated film in the present invention is a film in which a nickel-copper alloy thin film is laminated on at least one surface of the film substrate directly or via another layer. The nickel content of the nickel-copper alloy film is preferably 40% by weight or more and 95% by weight or less, more preferably 50% by weight or more and 90% by weight or less. If it is less than 40% by weight, chemical resistance and long-term storage stability are poor, and it becomes difficult to obtain a cyclic voltammetry evaluation result of a suitable ferrocyanide ion in the cyclic voltammetry evaluation described later, and it becomes difficult. It is used as an electrode for a blood sugar level sensor, and thus is not preferable. On the other hand, when it is more than 95% by weight, when it is produced by sputtering, the deposition rate is lowered and the productivity is deteriorated, which is not preferable. Further, in the case where the film contains a trace amount of oxygen or the like other than nickel and copper, the sum of the contents of nickel and copper does not always become exactly 100% by weight, and the content of copper is high. It is preferably about 5% by weight or more and 60% by weight or less.

Since the nickel-copper alloy film of the nickel-copper alloy film laminated film of the present invention has high crystallinity, in the X-ray diffraction pattern, at 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°. A diffraction peak is included in at least one of three ranges of ≦2θ ≦ 77°. Because of its high crystallinity, excellent chemical resistance and long-term storage stability, and suitable peaks in cyclic voltammetry of ferrocyanide ions, it can be suitably used as an electrode for blood glucose sensor. Furthermore, it can be seen that even if the nickel-copper alloy is crystalline or amorphous, even After immersing in a 3 wt% potassium ferricyanide aqueous solution for 20 days, the resistance value did not change. Therefore, the chemical resistance in the present invention is an acid resistance test under the conditions described in the examples below.

In the nickel-copper alloy thin film laminated film nickel-copper alloy film of the present invention, the ratio of the number of oxygen atoms measured by the depth analysis by X-ray photoelectron spectroscopy to the sum of the number of nickel atoms, the number of copper atoms, and the number of oxygen atoms is O/ (Ni + Cu + O) is preferably 0.05 or less, more preferably 0.04 or less in the range of the film. When it is 0.05 or less, it is excellent in chemical resistance and long-term storage stability, and it is easy to obtain a suitable result in a cyclic voltammetry method of a suitable ferrocyanide ion, and therefore it is preferably used as an electrode for a blood glucose sensor. use. It is preferable that the O/(Ni+Cu+O) value is small, and there is also a case where it becomes zero. In addition, it is said that the range of the nickel-copper alloy thin film portion means that there is no influence of the surface contaminant and the influence of the plastic film of the substrate, and only the range of the nickel-copper alloy film is reliably measured, as will be described later. Figure 2 measured under the conditions in the example: when the etching time becomes larger from zero, it means that the slope from O/(Ni+Cu+O) becomes -0.01 or more until the range of 0.01 is reached. .

The surface resistivity of the nickel-copper alloy thin film laminated film in the present invention is preferably 300 Ω/□ or less, more preferably 100 Ω/□ or less, and particularly preferably 50 Ω/□ or less. When the surface resistance value is 300 Ω/□ or less, the oxidation peak current and the reduction peak current can be surely confirmed in the above cyclic voltammetry evaluation, and the electric signal is surely obtained when used as an electrode of the blood glucose sensor. Better. It is preferable that the surface resistance value is low, but usually 0 Ω / □ cannot be achieved, and the lower limit thereof may be 0.01 Ω / □, or may be 1 Ω / □ or more.

In the present invention, it is preferred that the nickel-copper alloy thin film laminated film is in a cyclic voltammetry measurement of ferrocyanide ions using silver or silver chloride as a reference electrode, between +0.2V and +0.5V. The potential shows the peak current of oxidation. It is shown that the nickel-copper alloy film on the nickel-copper alloy thin film laminated film of the present invention does not dissolve in the ferrocyanide ions, but can oxidize the ferrocyanide ions into ferricyanide ions, which is confirmed to be An indicator of the appropriate action of the electrode of the blood glucose sensor. The peak oxidation current observed outside this range is caused by oxidation of substances other than ferrocyanide, and it does not depend on the operation as a blood glucose sensor electrode. In addition, when it is larger than +0.5 V, a large voltage is required to operate as a blood glucose sensor electrode, which is not preferable.

In the present invention, it is preferred that the nickel-copper alloy film laminate film exhibits a reduction peak current at a potential between 0 V and +0.3 V. It is shown that the nickel-copper alloy film on the nickel-copper alloy thin film laminated film of the present invention does not dissolve in the ferricyanide ion, but can reduce the ferricyanide ion to the ferrocyanide ion, which is confirmed to be useful as blood sugar. An indicator of the appropriate action of the electrodes of the value sensor. The reduction peak current observed outside this range is caused by the reduction of substances other than ferricyanide, and is not related to the proper operation as the blood glucose sensor electrode. The absolute values of the oxidation peak current and the reduction peak current vary depending on the measurement conditions, and are 0.05 mA in the conditions of the embodiment of the present invention. Above 2 mA. When it is 0.05 mA or more, the above-described redox reaction occurs as a nickel-copper alloy thin film, and the nickel-copper alloy thin film which is a problem does not elute, but the above-described redox reaction is normally generated. When it is 2 mA or less, it can be judged that the current value is not excessively large, and the nickel-copper alloy film which is a problem does not elute. In the present invention, the profile measured by the cyclic voltammetry when the above-mentioned necessary conditions are satisfied becomes, for example, a shape as shown in FIG.

Even if the nickel content in the nickel-copper alloy film is not 40% by weight or more and 95% by weight or less, or the nickel-copper alloy film is in the X-ray diffraction pattern at 43°≦2θ≦45°, 49°≦2θ≦52° And a nickel-copper alloy thin film laminated film which does not have a diffraction peak in any of the three ranges of 74° ≦ 2θ ≦ 77°, and also shows a current value depending on the glucose concentration in the cyclic voltammetry evaluation. However, the nickel-copper alloy film is unstable, so the reproducibility is low and it is not preferable.

Therefore, in order to function more suitably as an electrode for a blood sugar level sensor, it is preferable to satisfy the following requirements. That is, in the second measurement of the cyclic voltammetry, the oxidation and reduction peak currents which are substantially the same as the first measurement result are shown. Here, "substantially" means that the value of the potential for the oxidation and reduction peak current is ±0.05 V, and the oxidation and reduction peak current value is within ±20% of the absolute value. It is shown that the nickel-copper alloy film on the nickel-copper alloy thin film laminated film of the present invention does not dissolve and remains stably even after the oxidation reaction and the reduction reaction measured in the first time, and The surface morphology did not change, indicating that the nickel-copper alloy film is very suitable as an electrode for a blood glucose sensor.

The nickel-copper alloy thin film laminated film of the present invention has a structure in which a nickel-copper alloy thin film is laminated on at least one surface of the film substrate directly or via another layer. Hereinafter, each layer will be described in detail.

(film substrate)

The film substrate used in the present invention means that the organic polymer is melt-extruded into a film shape or subjected to solution extrusion to form a film, and is extended and thermally fixed in the longitudinal direction and/or the width direction as necessary. A film formed by thermal relaxation treatment. Examples of the organic polymer include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, polytrimethylene terephthalate, nylon 6, and nylon 4. Nylon 66, nylon 12, polyimine, polyamidimide, polyethersulfone, polyetheretherketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene Vinyl chloride, polyvinyl alcohol, polyether phthalimide, polyphenylene sulfide, polyphenylene ether, polystyrene, syndiotactic polystyrene, norbornene-based polymer, and the like.

Among these organic polymers, polyethylene terephthalate, polytrimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, syndiotactic polystyrene, norbornene-based polymer, Polycarbonate, polyarylate, and the like are preferred. In addition, the organic polymers may also copolymerize a small amount of a monomer of another organic polymer or may blend other organic polymers.

The thickness of the film substrate used in the present invention is preferably from 10 μm to 300 μm, more preferably from 20 μm to 250 μm. If the thickness of the plastic film is 10 μm or more, the mechanical strength can be satisfied, and the operation of the sensor such as the blood sugar level sensor can be generally ensured, which is preferable. On the other hand, when the thickness is 300 μm or less, the thickness of the sensor such as the blood glucose sensor is not excessively thick and preferable.

The film substrate used in the present invention may be subjected to corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, or electron beam irradiation on the film as described above without damaging the object of the present invention. Surface activation treatment such as treatment and ozone treatment.

Further, in the film substrate used in the present invention, it is preferable to provide a curing type for the purpose of improving the adhesion to the nickel-copper alloy film, imparting chemical resistance, and preventing precipitation of low molecular weight substances such as oligomers. The resin is a cured layer of a main constituent.

The curable resin is not particularly limited as long as it is cured by energy application such as heating, ultraviolet irradiation, or electron beam irradiation, and examples thereof include a silicone resin, an acrylic resin, a methacrylic resin, an epoxy resin, and a melamine resin. , polyester resin, urethane resin, and the like.

(nickel-copper alloy film)

The total film thickness of the nickel-copper alloy film in the present invention and the intermediate layer described later It is preferably in the range of 10 nm to 400 nm, more preferably 15 nm to 300 nm, and particularly preferably 20 nm to 250 nm. When the film thickness is 10 nm or more, the pinhole of the film formation is small, and when the electrode is used as the electrode of the blood glucose sensor, the electric signal can be surely obtained, which is preferable. On the other hand, when the film thickness is 400 nm or less, the rigidity of the nickel-copper alloy film is not excessively large, and there is no problem that the peeling or the adhesion is lowered, and the problem of warpage of the substrate does not occur, which is preferable. In the case of film formation by, for example, sputtering, the film thickness can be controlled by changing the speed at which the film passes over the nickel-copper alloy target.

The nickel-copper alloy film in the present invention preferably has a nickel content of 40% by weight or more and 95% by weight or less. If it is less than 40% by weight, it is difficult to obtain an evaluation result of a suitable cyclic voltammetry, and as a result, it becomes difficult to use it as an electrode for a blood glucose sensor. On the other hand, when it is more than 95% by weight, when it is produced by sputtering, the deposition rate is lowered and the productivity is deteriorated, which is not preferable.

Since the nickel-copper alloy film of the present invention has high crystallinity, it is in the X-ray diffraction pattern at 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77°. At least one of the ranges has a diffraction peak. Due to its high crystallinity, excellent chemical resistance and long-term storage stability, and suitable peaks in cyclic voltammetry of ferrocyanide ions, it is suitable for use as an electrode for blood glucose sensor.

In the nickel-copper alloy film of the present invention, the ratio of the number of oxygen atoms measured by the depth analysis by X-ray photoelectron spectroscopy to the sum of the number of oxygen atoms, the number of nickel atoms, and the number of copper atoms is O/(Ni+Cu+O It is considered to be 0.05 or less, more preferably 0.04 or less, in the range of the film. If it is more than 0.05, there is a case where chemical resistance and long-term storage stability are poor, and a suitable evaluation result cannot be obtained in a cyclic voltammetry method of a suitable ferrocyanide ion, and it becomes difficult to use it as an electrode for a blood sugar level sensor. use. It is preferable that O/(Ni+Cu+O) is small, and there is also a case where it becomes zero. Furthermore, the range of the nickel-copper alloy film is considered to be the influence of the surface-free contaminant and the influence of the plastic film of the substrate, and only the range of the nickel-copper alloy film is measured, as will be described later. In the case of the measurement under the condition of FIG. 2, when the etching time becomes larger from zero, it means that the slope of O/(Ni+Cu+O) becomes -0.01 or more until it reaches 0.01 or more.

The film thickness of the nickel-copper alloy film is preferably from 5 nm to 400 nm. When it is 5 nm or more, the effect of lowering the resistance value is obtained, and it is preferable. When it is 400 nm or less, the adhesion to the film substrate is maintained, and it is preferable that the film of the nickel-copper alloy is not laminated.

In order to improve the adhesion to the nickel-copper alloy film and to improve the productivity, any film layer of titanium or a nickel-titanium alloy may be provided as an intermediate layer between the substrate film and the substrate film. As for the film thickness of the intermediate layer, as long as it is a nickel-copper alloy The film thickness of the entire film may be appropriately set so as to be in the range of 10 nm to 400 nm. The composition of the nickel-titanium alloy can be arbitrarily selected.

<Method of Film Formation of Nickel-Copper Alloy Film>

As a film forming method of the nickel-copper alloy film in the present invention, a vacuum vapor deposition method, a sputtering method, a chemical vapor deposition (CVD) method, an ion plating method, and the like are known. In the spray method or the like, the above method can be suitably used depending on the desired film thickness. However, from the viewpoint of exhibiting high adhesion or reducing the unevenness of the film thickness, a sputtering method is preferred.

At this time, it is also possible to use a combination of plasma irradiation, ion assist, and the like. Further, a bias voltage such as a direct current, an alternating current, or a high frequency may be applied to the substrate within a range not impairing the object of the present invention.

If water is contained in the film formation environment at the time of sputtering, crystallization of the nickel-copper alloy film is inhibited. Therefore, the amount of water in the film forming environment is an important factor. In order to reduce the amount of water in the film forming environment, it is preferable to perform sputtering by setting the partial pressure ratio of water in the film forming environment at the time of sputtering to the inert gas to 8.0 × 10 ^-4 to 1.0 × 10 ^-2 . The longer the vacuuming time of the vacuum chamber is, the more the water pressure in the film formation during sputtering is reduced. Therefore, the partial pressure ratio of the water in the film forming environment to the inert gas during sputtering can be controlled by changing the vacuuming time. . When the partial pressure ratio of the water to the inert gas is 1.0 × 10 ^-2 or less, the nickel-copper alloy film is not inhibited from being crystallized, and a film having good chemical resistance and long-term storage stability is obtained, and the blood sugar value is felt. When the electrode for the detector is used, it becomes easy to obtain a suitable signal. When the partial pressure ratio of the water to the inert gas is 8.0 × 10 ^-4 or more, the vacuum pump can be adjusted without particularly performing a long time of vacuuming, and a vacuum pump having a high capacity is not particularly required, and it is relatively easy to economically implement. .

Further, when the partial pressure ratio of water to the inert gas is more than 1.0 × 10 ^-2 , the oxygen atom ratio O / (Ni + Cu + O) is not 0.05 or less, and from this point of view, it is also preferable. The partial pressure ratio of water to inert gas was set to 8.0 × 10 ^-4 to 1.0 × 10 ^-2 for sputtering.

In order to control the amount of water when the film is formed into a plastic film, it is desirable to actually observe the amount of water at the time of film formation. As for the use of ultimate vacuum in the control of the moisture content in the film formation environment, it is not preferable as described in the following two points. First, at the first point, when a film is formed by sputtering, the film is heated, the amount of water in the film forming environment is increased, and the amount of water at the time of measuring the ultimate vacuum is further increased.

The second point is a case where a device that is heavily loaded into a plastic film is used. In such a device, a film is placed in a roll. When the film is rolled into a vacuum chamber, the outer portion of the wound of the roll is easily dehydrated, but the inner portion of the wound of the roll is difficult to be dehydrated. When the ultimate vacuum is measured, although the film roll stops, the film roll travels at the time of film formation, so that the inner portion of the wound containing a large amount of water starts to be unwound, and thus the moisture in the film forming environment As the amount increases, the amount of water at the time of measuring the ultimate vacuum is further increased. In the present invention, when controlling the amount of water in the film formation environment, it is dealt with by observing the partial pressure ratio of water in the film formation environment at the time of sputtering with respect to the inert gas.

In the film formation, it is desirable to form a nickel-copper alloy thin film layer on the film substrate while maintaining the temperature of the film substrate at 80 ° C or lower. When it is 80 ° C or less, water from the film substrate is not generated in a large amount, and it is relatively easy to promote the partial pressure ratio of water in the film formation environment at the time of sputtering to the inert gas to 1.0 × 10 ^-2 or less. Since the nickel-copper alloy film is crystallized, the chemical resistance and the long-term storage stability are improved, and it is preferable to obtain a suitable signal when it is used as an electrode for a blood sugar level sensor. Further, it is preferable that a large amount of impurity gas such as an organic gas is generated and crystallization of the nickel-copper alloy film is relatively easily promoted.

Further, as long as the temperature of the film substrate is 80 ° C or less, water from the film is not generated in a large amount, and it becomes relatively easy to make the partial pressure ratio of water in the film forming environment to the inert gas at the time of sputtering 8.0 × 10 ^-3 or less, it is easy to adjust O/(Ni+Cu+O) to 0.05 or less. Further, since an impurity gas such as an organic gas is not generated in a large amount, it is preferable to adjust O/(Ni + Cu + O) to 0.05 or less. Further, as for the temperature of the film substrate in the film formation, if the film formation method is a sputtering method, it can be adjusted by the center roll temperature of the device, substantially even if the center roll temperature and the temperature of the film substrate are regarded as The same is no problem.

The nickel-copper alloy thin film laminated film obtained in the above manner can be preferably used as an electrode film for a blood glucose sensor by performing desired patterning by a method such as photolithography. The electrode membrane for a blood sugar level sensor can be used as a blood glucose sensor strip corresponding to the type of the blood glucose sensor device, and is attached to the blood glucose sensor device for use.

[Examples]

Hereinafter, the present invention will be described in more detail by way of examples, but the invention should not be construed as limited. Further, the characteristics of the nickel-copper alloy film laminated film can be measured by the following method.

(1) X-ray diffraction pattern

Using the CuKα ray as a light source, the acceleration voltage was set to 40 kV, the current was set to 30 mA, the measurement interval was set to 0.1°, and the X-ray diffraction pattern of the negative electrode active material film was measured by an in-plane method.

(2) Analysis of the composition of the depth direction by X-ray photoelectron spectroscopy

The excitation X-ray is set to AlKα ray, the output is set to 14 kV, 26 mA, the photoelectron escape angle is set to 45°, the pass energy is set to 29.35 eV, and the step is set to 0.125 eV. The degree of vacuum was set to 4 × 10 ^-6 Pa or less, and the etching rate was set to 1.9 nm/min (in terms of SiO ₂ ), and composition analysis in the depth direction was performed. Data were collected between 0 minutes and 3 minutes with an interval of 1 minute, and data was collected from 3 minutes after 3 minutes.

(3) Surface resistance value

The measurement was performed by a four-terminal method in accordance with JIS-K7194. The measuring machine uses the Lotest AMCP-T400 manufactured by Mitsubishi Petrochemical Co., Ltd.

(4) Thickness of nickel-copper alloy film and intermediate layer

The nickel-copper alloy thin film laminated film sample piece was cut into a size of 1 mm × 10 mm, and embedded in an epoxy resin for electron microscopy. This was fixed to a sample holder of an ultramicrotome to prepare a thin slice of the section parallel to the short side of the embedded sample piece. Next, in the portion where the film of the slice was not significantly damaged, a transmission electron microscope (manufactured by Japan Electron Optics Laboratory Co., Ltd., JEOL, JEM-2010) was used, and the acceleration voltage was The film was taken at a magnification of 10,000 times at 200 kV and a bright field, and the film thickness was determined from the obtained photograph.

In the case where the intermediate layer of the film of titanium or nickel-titanium alloy is contained between the base film and the nickel-copper alloy film, there is an interface between the intermediate layer and the nickel-copper alloy film, and the contrast between the intermediate layer and the nickel-copper alloy film is different, The respective film thicknesses can be measured.

(5) Cyclic voltammetry measurement

The nickel-copper alloy film laminate film was cut into a strip shape of 50 mm × 5 mm width. Impregnated in an aqueous solution containing 5 mM potassium ferrocyanide and 1 M potassium nitrate 10mm short strip nickel-copper alloy film laminate film. The silver or silver chloride of the reference electrode and the platinum coil of the opposite electrode are also disposed in the solution. In the case of silver or silver chloride, the initial voltage was first set to +0.1 V, the return voltage was set to +0.5 V, and the end voltage was set to +0.1 V, and the measurement was performed at a scanning speed of 50 mV/s. When the peak oxidation current and the peak current are reduced in the range of +0.1 V to +0.5 V, the above measurement is taken as the first measurement, and then the second measurement is also performed under the same conditions. Observing the potential between the oxidation peak current and the potential between 0V and +0.3V at a potential between +0.2V and +0.5V, the reduction peak current is observed to be substantially the same in the first and second measurements. Table 1 shows ○.

(6) Chemical resistance (acid resistance) test

The nickel-copper alloy film laminate film was immersed in a hydrochloric acid solution of pH=4 for 24 hours. The resistance value before immersion was set to R0, and the surface resistance value after immersion was set to R1, and it was judged by the value of R1/R0. The range of R1/R0 < 1.2 is good.

(7) Long-term preservation stability

The nickel-copper alloy film laminate film was set in a constant temperature and humidity chamber at 60 ° C / 90% RH for 500 hours, and the surface resistance value before the setting was set to R0, and the surface resistance value after the setting was set to R2, by R2/ The value of R0 is judged. The range of R2/R0 < 1.1 is good.

[Example 1]

As the plastic film, a biaxially stretched polyethylene terephthalate film (E5001, manufactured by Toyobo Co., Ltd.) having a thickness of 250 μm was used.

The membrane was placed in a vacuum chamber and evacuated. The partial pressure ratio of water to inert gas was 5.0 × 10 ^-3 . Thereafter, the center roll temperature was set to 0 °C. A argon gas as an inert gas was introduced to a total pressure of 0.15 Pa, and electric power was supplied at a power density of 3 W/cm ^{2 to} form a nickel-copper alloy thin film by a DC magnetron sputtering method. Regarding the film thickness, it is possible to control the speed at which the film passes through the target. In addition, the partial pressure ratio of the water in the film formation environment at the time of sputtering to the inert gas was measured using a gas analyzer (manufactured by INFICON, Transpector XPR3).

1 is an X-ray diffraction pattern of a nickel-copper alloy thin film laminated film of Example 1. The diffraction peaks were confirmed in three ranges of 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77°, and the crystallinity was high.

Fig. 2 is a view showing the depth analysis of the nickel-copper alloy thin film laminated film of Example 1 by X-ray photoelectron spectroscopy. Regarding O/(Ni+Cu+O), the maximum value is 0.029 in the range of the nickel-copper alloy film.

Fig. 3 is a graph showing the results of cyclic voltammetry (CV) measurement of the nickel-copper alloy thin film laminated film of Example 1. In the first measurement, the peak current of oxidation was observed at a potential of +0.32 V at a potential of +0.45 mA, at a frequency of +0.22 V. The reduction peak current was observed at a current of -0.31 mA. In the second measurement, the oxidation peak current was observed at a potential of +0.32 mA at a potential of +0.32 V, and the reduction peak current was observed at a potential of +0.32 mA at a potential of +0.22 mA. In the first measurement, the oxidation peak current and the reduction peak current were observed at a suitable potential, and the second measurement was substantially the same as the first measurement.

Further, as shown in Table 1, the nickel-copper alloy thin film laminated film of Example 1 showed good acid resistance and long-term storage stability.

[Embodiment 2]

The same procedure as in Example 1 was carried out except that the partial pressure ratio of the water to the inert gas was changed to 1.0 × 10 ^-3 and the film thickness was changed to 50 nm. The two ranges have diffraction peaks at 43°≦2θ≦45° and 49°≦2θ≦52°. Regarding O/(Ni+Cu+O), it is considered to be the range of the nickel-copper alloy film. The value was 0.021, which showed good results in cyclic voltammetry evaluation, acid resistance, and long-term storage stability.

[Example 3]

The film thickness was changed to 200 nm, and the same procedure as in Example 1 was carried out. The three ranges have diffraction peaks at 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77°. Regarding O/(Ni+Cu+O), it is indeed considered to be Among the nickel-copper alloy films, the maximum value was 0.025, which showed good results in cyclic voltammetry evaluation, acid resistance, and long-term storage stability.

[Example 4]

The same procedure as in Example 1 was carried out except that the content of nickel was changed to 75% by weight. At 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77°, the three ranges have diffraction peaks, and the oxygen atom ratio O/(Ni+Cu+O) is true. It is considered to be a nickel-copper alloy film with a maximum value of 0.021, which shows good results in cyclic voltammetry evaluation, acid resistance, and long-term storage stability.

[Example 5]

The same procedure as in Example 1 was carried out except that the partial pressure ratio of water to inert gas was changed to 8.0 × 10 ^-3 and the content of nickel was changed to 90% by weight. The three ranges have diffraction peaks at 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77°. Regarding O/(Ni+Cu+O), it is indeed considered to be Among the nickel-copper alloy films, the maximum value was 0.035, which showed good results in cyclic voltammetry evaluation, acid resistance, and long-term storage stability.

[Embodiment 6]

The film thickness was changed to 20 nm, and the same procedure as in Example 1 was carried out. It has a diffraction peak in the range of 43 ° ≦ 2θ ≦ 45 °. Regarding O / (Ni + Cu + O), in the range of the nickel-copper alloy film, the maximum value is 0.035, which is evaluated by cyclic voltammetry. Good results in acid resistance and long-term storage stability.

[Embodiment 7]

The same procedure as in Example 1 was carried out except that the content of nickel was changed to 75% by weight, and a titanium thin film of 50 nm was provided as an intermediate layer by sputtering. The three ranges have diffraction peaks at 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77°. Regarding O/(Ni+Cu+O), it is indeed considered to be Among the nickel-copper alloy films, the maximum value was 0.025, which showed good results in cyclic voltammetry evaluation, acid resistance, and long-term storage stability.

[Embodiment 8]

The same procedure as in Example 1 was carried out except that the content of nickel was changed to 75% by weight, and a nickel-titanium film of 30 nm was provided by sputtering as an intermediate layer. At 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77°, the three ranges have diffraction peaks, and the oxygen atom ratio O/(Ni+Cu+O) is true. It is considered to be a nickel-copper alloy film with a maximum value of 0.021, which shows good results in cyclic voltammetry evaluation, acid resistance, and long-term storage stability.

[Embodiment 9]

On the easy-adhesion layer of a biaxially-oriented polyethylene terephthalate film (A4100, manufactured by Toyobo Co., Ltd.) having an easy adhesion layer on the surface of 188 μm, the thickness of the coating film was 3000 nm, and the micro-gravure was used. The following coating liquid was applied by a micro gravure method.

. Toluene 30% by mass

. Methyl ethyl ketone 30% by mass

. UV curable resin 40% by mass

(BEAMSET 700, acrylate manufactured by Arakawa Chemical Co., Ltd.)

. UV polymerization initiator 2% by mass

(Irgacure 184, manufactured by Ciba Japan K.K.)

After drying at 80 ° C for 1 minute, the coating film was cured by irradiation with ultraviolet rays (light amount: 300 mJ/cm ² ) using an ultraviolet irradiation device (manufactured by EYE GRAPHICS Co., Ltd., UB042-5AM-W type). A nickel-copper alloy film having a partial pressure ratio of water to an inert gas of 8.0 × 10 ^-3 and a nickel-plated nickel of 90% by weight was used. As for O/(Ni+Cu+O), the maximum value is 0.042 in the range of the nickel-copper alloy film, and is in the range of 43°≦2θ≦45° and 49°≦2θ≦52°. The diffraction peak shows the results of cyclic voltammetry evaluation and good acid resistance. In the long-term storage stability, although the results were slightly inferior to those of the other examples, it was preferable in general.

[Embodiment 10]

On the easy-adhesion layer of a biaxially-oriented polyethylene terephthalate film (A4100, manufactured by Toyobo Co., Ltd.) having an easy adhesion layer on the surface of 188 μm, the thickness of the coating film was 3000 nm, and the micro-gravure was used. The same coating liquid as in Example 9 was applied by the method. After drying at 80 ° C for 1 minute, the coating film was cured by irradiation with ultraviolet rays (light amount: 300 mJ/cm ² ) using an ultraviolet irradiation device (manufactured by EYE GRAPHICS Co., Ltd., UB042-5AM-W type). A nickel-copper alloy film having a partial pressure ratio of water to an inert gas of 5.0 × 10 ^-3 and a nickel-plated sputtering of 75% by weight was used. As for O/(Ni+Cu+O), in the range of the nickel-copper alloy film, the maximum value is 0.032, and the range is 43°≦2θ≦45°, and 49°≦2θ≦52°. With a diffraction peak, in the range of O/(Ni+Cu+O), which is considered to be a nickel-copper alloy film, the maximum value is 0.032, which is shown in cyclic voltammetry evaluation, acid resistance, and long-term storage stability. Good results.

[Comparative Example 1]

The same procedure as in Example 1 was carried out except that the partial pressure ratio of the water in the film formation environment at the time of the sputtering was changed to 1.0 × 10 ^-3 and the nickel was changed to 35% by weight. The content of nickel is not suitable, so it is not a suitable result in the evaluation of cyclic voltammetry, and it is a result of poor acid resistance or poor long-term storage stability.

[Comparative Example 2]

The same procedure as in Example 1 was carried out except that the partial pressure ratio of the water in the film formation environment at the time of the sputtering was changed to 4.0 × 10 ^-2 and the nickel was changed to 65% by weight. There is no diffraction peak. As for O/(Ni+Cu+O), there is a region larger than 0.05 in the range of the nickel-copper alloy film. It is not a suitable cyclic voltammetry evaluation result. The result of poor acid resistance.

[Comparative Example 3]

The same procedure as in Example 1 was carried out except that the partial pressure ratio of the water in the film formation environment at the time of the sputtering was changed to 4.0 × 10 ^-2 and the nickel was changed to 75% by weight. There is no diffraction peak. As for O/(Ni+Cu+O), a region larger than 0.05 is surely considered to be a nickel-copper alloy film, which is a result of poor acid resistance.

[Comparative Example 4]

The same procedure as in Example 1 was carried out except that the partial pressure ratio of the water in the film formation environment at the time of the sputtering was changed to 4.0 × 10 ^-2 and the nickel was changed to 90% by weight. There is no diffraction peak. As for O/(Ni+Cu+O), a region larger than 0.05 is surely considered to be a nickel-copper alloy film, which is a result of poor acid resistance.

[Comparative Example 5]

The same procedure as in Example 1 was carried out except that the film was changed to a nickel-titanium alloy (nickel: 92.5 wt%). The combination of metals is not suitable, so the evaluation results of suitable cyclic voltammetry are not shown, which is a result of poor long-term storage stability.

[Comparative Example 6]

The same procedure as in Example 1 was carried out except that the film was changed to a nickel-tungsten alloy (81% by weight of nickel). The combination of metals is not suitable, so the evaluation results of the suitable cyclic voltammetry are not shown, and the result is poor acid resistance.

[Industrial availability]

Since the nickel-copper alloy thin film laminated film of the present invention has high crystallinity and is excellent in chemical resistance and long-term storage stability, it can be suitably used as an electrode film for a blood glucose sensor.

Claims (9)

A nickel-copper alloy thin film laminated film which is formed by laminating a film of a nickel-copper alloy film directly on at least one surface of a film substrate or via another layer, and the nickel content in the nickel-copper alloy film is 40% by weight or more 95% by weight or less, the nickel-copper alloy film is at least 1 in the X-ray diffraction pattern at 43°≦2θ≦45°, 49°≦2θ≦52°, and 74°≦2θ≦77° The range has a diffraction peak. The nickel-copper alloy thin film laminated film according to claim 1, wherein the ratio of the number of oxygen atoms in the nickel-copper alloy thin film to the sum of the number of nickel atoms, the number of copper atoms, and the number of oxygen atoms is O/(Ni+Cu+O) It is 0.05 or less. The nickel-copper alloy thin film laminated film according to claim 1 or 2, wherein the surface resistance value is 300 Ω/□ or less. The nickel-copper alloy thin film laminated film according to claim 1 or 2, wherein an intermediate layer is provided between the film substrate and the nickel-copper alloy film, and the intermediate layer is a film of titanium or a nickel-titanium alloy. The nickel-copper alloy thin film laminated film according to claim 4, wherein a total thickness of the nickel-copper alloy thin film and the intermediate layer is 10 nm or more and 400 nm or less. The nickel-copper alloy thin film laminated film according to claim 1, 2 or 5, which satisfies the following requirements: (1) cyclic voltammetry measurement of ferrocyanide ions using silver or silver chloride as a reference electrode In the middle, the potential between +0.2V and +0.5V shows the peak current of oxidation, and the potential between 0V and +0.3V shows the peak current of reduction; (2) The oxidation peak current and the reduction peak current measured by the second cyclic voltammetry are shown as the oxidation peak current measured by the first cyclic voltammetry when the cyclic voltammetry measurement is performed. A current that is substantially the same as the peak current reduction. An electrode film for a blood glucose sensor, which is obtained by patterning a nickel-copper alloy film constituting the nickel-copper alloy thin film laminated film according to any one of claims 1 to 6. A blood glucose sensor strip for use in an electrode film for a blood glucose sensor according to claim 7. A blood sugar level sensor device using the blood glucose sensor strip as recited in claim 8.