JP2007021974A - Metallized film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallized film which has an excellent metal surface whose surface resistance changes very little and whose water contact angle hardly changes and is excellent for use in an immobilized enzyme electrode for an invitro diagnosis cell for an examination kit. <P>SOLUTION: The metallized film has one or more metal layers laminated on a polymer film substrate. The outermost layer is a metal layer composed of gold and/or platinum. The center line average roughness (Ra) of the metal layer surface of the outermost layer is 5-150 nm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metallized film having an excellent metal surface in which a change in surface resistance value is extremely small and a change in water contact angle hardly occurs.

  Various test kits have been developed to easily obtain biological information. As an example, a test kit in which an electrode is coated with a substance containing glucose oxidase and potassium ferricyanide has been proposed. Glucose in the blood is broken down by glucose oxidase, and at the same time, potassium ferricyanide is oxidized to potassium ferrocyanide. Potassium ferrocyanide returns to potassium ferricyanide by an oxidation-reduction reaction on an electrode applied with a constant voltage. A current due to this oxidation-reduction reaction flows through the electrode, and the amount of glucose in the blood can be measured from the amount of current, which is known as an immobilized enzyme electrode method (Patent Documents 1 and 2).

When an expensive metal is used as an electrode, if a metal laminated film is used, there is an advantage that a small amount of a thin metal can serve as an electrode, and an inspection kit can be continuously produced. Therefore, the development of a thin film electrode made of metal was advanced, but since the water contact angle on the surface of the thin film electrode increased with time in the atmosphere, a substance containing glucose oxidase and potassium ferricyanide could not be uniformly coated. However, there is a problem in that it is impossible to accurately measure the current generated with the redox reaction. Therefore, as a means for solving this problem, there has been proposed a method (Patent Document 3) in which a metallized film is packed in a moisture-proof bag and opened immediately before coating with a substance containing glucose oxidase. However, even if the moisture-proof packaging method is used, the inflow of outside air cannot be completely blocked.
European Patent No. 359831 (page 3, column 3, line 33 to column 4, line 48) Japanese Patent Laid-Open No. 5-196595 (page 2, column 1, line 20 to column 2, line 2) JP-A-2004-325294 (paragraphs [0008] to [0018])

  In view of the background of such a conventional technique, the present invention provides an excellent metallized film for an electrode having an excellent metal surface in which the change in surface resistance value is extremely small and the change in water contact angle hardly occurs. Is.

  The present invention employs the following means in order to solve such problems. That is, the metallized film of the present invention is a metallized film in which one or more metal layers are laminated on a polymer film substrate, and the outermost layer is a metal layer composed of gold and / or platinum, and The metallized film having a center line average roughness (Ra) of 5 to 150 nm on the outermost metal layer surface.

  According to the present invention, it is possible to provide a metallized film in which the change in the surface resistance value on the metal surface is extremely small and the change in the water contact angle on the metal surface is unlikely to occur. As an immobilized enzyme electrode, an excellent material can be provided as an electrode for capturing a redox potential or redox current due to a redox reaction.

  The present invention has been intensively studied on the metallized film having an excellent metal surface in which the above problem, that is, the change in the surface resistance value is extremely small and the change in the water contact angle hardly occurs, and a metal having one or more metal layers. When the outermost layer of the modified film is made of a specific noble metal and the center line average roughness (Ra) of the outermost layer surface is controlled within a specific range, it has been found that such problems can be solved at once. Is.

  That is, in the metallized film of the present invention, the outermost layer is composed of gold and / or platinum, and the center line average roughness (Ra) of the outermost layer surface is controlled within a range of 5 to 150 nm.

  In the present invention, the metallized film means a film in which a metal layer is laminated on the surface of a polymer film substrate.

  The material which comprises the polymer film base material in this invention is not specifically limited, It can select suitably from the raw materials of a well-known plastic film base material, and can use it. As a material of such a plastic film substrate, for example, polyester, polyethylene, polypropylene, diacetate, triacetate, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyether ethyl ketone, Resins selected from polyimide, fluorine, nylon and polymethacrylic resins can be used. Among these resins, it is preferable to use a polyester film made of a polyester resin from the viewpoint of toughness and uniformity.

  As the polyester of the polyester film, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, or the like can be used. In addition, those polyesters obtained by copolymerizing other dicarboxylic acid components and diol components in a range of 20 mol% or less can also be used. These constituent components may be used alone or in combination of two or more. Among them, polyethylene terephthalate is particularly preferably used in view of quality, economy and the like.

  The thickness of the polymer film substrate is not particularly limited, but is preferably 5 to 800 μm, more preferably 10 to 250 μm, from the viewpoint of mechanical strength and thermal conductivity.

  In addition, the metallized film of the present invention is subjected to surface treatment on the surface of the film substrate, that is, for example, corona discharge treatment, glow discharge treatment, flame treatment, etching treatment, or roughening treatment before the metal layer is provided. Moreover, the center line average roughness (Ra) can be adjusted by such surface treatment. Similarly, before providing the metal layer, surface coating, that is, by applying a polyurethane-based, polyester-based, polyester acrylate-based, polyurethane acrylate-based, polyepoxy acrylate-based resin, titanate-based compound, or the like. The center line average roughness (Ra) of the metallized film surface can be adjusted, and the adhesion of the metal layer can be enhanced.

  As the metal material constituting the metal layer, any metal can be used as long as it is difficult to oxidize and has electrical conductivity. In particular, from the viewpoint of chemical stability, gold, silver, platinum group (ruthenium, Use of a noble metal such as rhodium, osmium, palladium, iridium, or platinum is preferable because it can be suitably used for electrode applications for electrically capturing changes due to chemical reactions, for example, electrodes for inspection kits. The metal which comprises this metal layer may be 1 type, or may use 2 or more types together. A plurality of types of metals may be laminated, or an alloy.

However, in order to solve the problem of the present invention,
As shown in FIG. 1, a metal layer 2 made of gold and / or platinum is laminated on the polymer film substrate 1, or
-As shown in FIG. 2, it is necessary to laminate | stack a several metal layer on the polymer film base material 1, and to make the outermost metal layer into the metal layer 2 comprised with gold | metal | money and / or platinum. .

  That is, even if the outermost metal layer is composed of a noble metal other than gold or platinum, the chemical stability of the outermost surface of the metallized film cannot be improved, and the outermost surface of the metallized film The change in water contact angle cannot be suppressed.

  In the metallized film of the present invention, the method of laminating the metal layer on the polymer film substrate includes a resistance heating method, an induction heating method, an electron beam method, a sputtering method, an ion plating method and the like. Among these, the sputtering method is particularly preferable from the viewpoints of film uniformity and adhesion.

  The metallized film of the present invention is further coated on the outermost metal layer surface with a substance mainly composed of enzymes such as glucose oxidase, lactate oxidase, cholesterol oxidase, etc. It can be used as a diagnostic cell. The substance used for coating is appropriately selected according to the substance to be reacted.

  Further, from the viewpoint of obtaining uniformity when immobilized on the metallized film, the substance to be coated on the metal surface is preferably dissolved or dispersed in a solvent and then coated on the surface of the metallized film. The solvent is not particularly limited, but it is preferable to use water in view of economy and safety.

  The center line average roughness (Ra) of the outermost metal layer surface of the metallized film in the present invention needs to be in the range of 5 to 150 nm. By adjusting the value of the center line average roughness (Ra), the contact area between the water droplet and the metal surface can be adjusted, so that the water contact angle in the outermost layer can be appropriately adjusted.

  The centerline average roughness (Ra) of the metal layer surface of the outermost layer of the metallized film is a value when measured and calculated based on JIS-B-0601 with a cut-off value of 0.08 mm. In the cross section of the metallized film, surface roughness having a long wavelength equal to or greater than the cutoff value is blocked.

  When the center line average roughness (Ra) is less than 5 nm, the water contact angle in the outermost layer becomes too high, and it becomes difficult to uniformly apply the coating substance to the metal surface of the outermost layer.

  In addition, when the center line average roughness (Ra) exceeds 150 nm, it becomes difficult to obtain a uniform surface resistance value with respect to the measurement position. Therefore, for in-vitro diagnosis used in a test kit that electrically captures a change caused by a chemical reaction. It cannot be used as a cell electrode application.

  The centerline average roughness (Ra) of the metallized film can be adjusted by appropriately selecting a polymer film substrate having a value close to the target centerline average roughness (Ra). Moreover, the said surface treatment or the said surface coating is given to a film base material, and the centerline average roughness (Ra) after metal lamination | stacking is adjusted by adjusting the centerline average roughness (Ra) of a film base material. You can also.

  The surface resistance value of the metallized film in the present invention is a value when measured with a test voltage of 100 V based on JIS-C-2318.

  The metallized film in the present invention preferably does not cause chemical changes such as oxidation. The metallized film should have a change in the surface resistance value in the air within 20Ω / □, more preferably a constant value, particularly in electrode applications for electrically capturing changes due to chemical reactions. However, when the metal surface is chemically unstable, an oxide film or the like is formed on the metal surface due to a chemical change, so that the surface resistance value changes and an accurate value may not be obtained.

〔Evaluation methods〕
For the metallized films prepared in each of the examples and comparative examples, the center line average roughness (Ra), liquid spreadability, and surface resistance value of the outermost metal layer surface were measured. These measurements were performed immediately after laminating the metal on the polymer film substrate and after leaving the metallized film in the atmosphere for 15 minutes. While the metallized film was allowed to stand, the atmospheric temperature was 20 ° C. and the relative humidity was 40 to 60%.

(1) Centerline average roughness (Ra)
Measurement was performed using a high-precision thin film level difference meter (ET-10, manufactured by Kosaka Laboratory Ltd.), and the center line average roughness (Ra) was determined based on JIS-B-0601. The radius of the stylus tip was 0.5 μm, the needle pressure was 5 mg, the measurement length was 1 mm, and the cutoff value was 0.08 mm.

(2) Liquid developability Glucose injection solution “Otsuka sugar solution 50%” (manufactured by Otsuka Pharmaceutical Co., Ltd.) 50 μl is dropped onto the metal surface of the metallized film, and the liquid from the wet state of glucose injection solution 30 seconds after dropping is liquid. Deployability was judged. Here, the wet spread state of the glucose injection solution is the diameter of the liquid, and when the liquid is elliptical, it is the short diameter. If the wet spread of the glucose injection solution is 10 mm or more, the liquid developability is good.
(3) Surface resistance value The surface resistance value of the metallized film was measured using a surface resistivity meter (Digital Hitester 3256 manufactured by Hioki Electric Co., Ltd.). A metallized film was cut into a size of 35 mm × 280 mm, and the value at the center was measured. The surface resistance value immediately after depositing the metal on the polymer film substrate and the surface resistance value after being left in the air for 15 minutes were measured, and the change in the surface resistance value represented by the following formula was determined. If the change in the surface resistance value is less than 20Ω / □, the stability of the surface resistance value in the atmosphere is good.
・ Change in surface resistance value (Ω / □) = Surface resistance value after standing in air (Ω / □)-Surface resistance value immediately after metal deposition (Ω / □)
Moreover, in the metallized film immediately after vapor-depositing the metal produced by each Example and the comparative example, ten metallized films of a size of 35 mm x 280 mm were cut out, and the surface resistance value of the center part was measured, respectively. The maximum and minimum values of the surface resistance values for these 10 different measurement positions are obtained, and the uniformity of the surface resistance values at the measurement positions is evaluated from the difference between the maximum and minimum surface resistance values expressed by the following formula. did. If the difference between the maximum value and the minimum value of the 10 surface resistance values obtained by the above measurement is less than 20Ω / □, the uniformity of the surface resistance value with respect to the measurement position is good.
・ Surface resistance difference (Ω / □) = Maximum surface resistance (Ω / □)-Minimum surface resistance (Ω / □)
[Example 1]
A 100 μm polyester film 100E20 (manufactured by Toray Industries, Inc.) is used as a film substrate, a 10 nm thick gold film is formed on one surface of the film substrate using a magnetron sputtering apparatus, and a metallized film is formed. Created. The target was gold having a purity of 99.99% (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.). Argon was used as the sputtering gas. The center line average roughness (Ra) of the outermost metal layer was 100 nm. The liquid spreadability was good both immediately after metal lamination and after being left in the atmosphere for 15 minutes. The stability of the surface resistance value was good, with the amount of change in resistance value after standing for 15 minutes in the air immediately after metal lamination being less than 5Ω / □. Further, the difference between the maximum value and the minimum value of the surface resistance value was less than 20Ω / □, and the uniformity of the surface resistance value with respect to the measurement position was good.

[Example 2]
A 100 μm polyester film 100E20 (manufactured by Toray Industries, Inc.) is used as a film substrate, and a palladium film having a film thickness of 10 nm is formed on one surface of the film substrate using a magnetron sputtering apparatus. A metallized film was prepared by forming a 10 nm gold film on the palladium film. The target is gold of 99.99% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a gold film, and palladium of 99.9% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a palladium film. Was used. Argon was used as the sputtering gas. The center line average roughness (Ra) of the outermost metal layer was 100 nm. The liquid spreadability was good both immediately after metal lamination and after being left in the atmosphere for 15 minutes. The stability of the surface resistance value was good, with the amount of change in resistance value after standing for 15 minutes in the air immediately after metal lamination being less than 5Ω / □. Further, the difference between the maximum value and the minimum value of the surface resistance value was less than 20Ω / □, and the uniformity of the surface resistance value with respect to the measurement position was good.

Example 3
A 100 μm polyester film 100T60 (manufactured by Toray Industries, Inc.) was used as a film substrate, and the surface of the film substrate was subjected to corona discharge treatment in the air, and then a palladium film having a film thickness of 10 nm using a magnetron sputtering apparatus. Was formed on the corona-treated surface of the film substrate, and a gold film with a film thickness of 10 nm was further formed on the palladium film to prepare a metallized film. The target is gold of 99.99% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a gold film, and palladium of 99.9% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a palladium film. Was used. Argon was used as the sputtering gas. The treatment time of the corona discharge was adjusted so that the center line average roughness (Ra) of the outermost metal layer was 100 nm. The liquid spreadability was good both immediately after metal lamination and after being left in the atmosphere for 15 minutes. The stability of the surface resistance value was good, with the amount of change in resistance value after standing for 15 minutes in the air immediately after metal lamination being less than 5Ω / □. Further, the difference between the maximum value and the minimum value of the surface resistance value was less than 20Ω / □, and the uniformity of the surface resistance value with respect to the measurement position was good.

Example 4
A 100 μm polyester film 100T60 (manufactured by Toray Industries, Inc.) was used as the film substrate. A solution in which tetraisopropyl titanate (manufactured by Matsumoto Pharmaceutical Co., Ltd., Olgatics TA-10), ethanol, and 0.1 N hydrochloric acid are dispersed so as to have a mass ratio of 5: 95: 1 is prepared to hydrolyze titanate. A liquid was obtained. A polyester film having a titanate coated on the surface is applied by applying the hydrolyzate on the film substrate using a bar coater, drying at 100 ° C. for 5 seconds, and performing heat treatment at 200 ° C. for 10 seconds using an oven. Obtained. Using a magnetron sputtering apparatus, a 10 nm thick palladium film is formed on the coating surface of the film substrate, and further a 10 nm thick gold film is formed on the palladium film, thereby forming a metallized film. Created. The target is gold of 99.99% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a gold film, and palladium of 99.9% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a palladium film. Was used. Argon was used as the sputtering gas. The thickness of the coating layer was adjusted so that the center line average roughness (Ra) of the outermost metal layer was 100 nm. The liquid spreadability was good both immediately after metal lamination and after being left in the atmosphere for 15 minutes. The stability of the surface resistance value was good, with the amount of change in resistance value after standing for 15 minutes in the air immediately after metal lamination being less than 5Ω / □. Further, the difference between the maximum value and the minimum value of the surface resistance value was less than 20Ω / □, and the uniformity of the surface resistance value with respect to the measurement position was good.

[Comparative Example 1]
Using a 100 μm polyester film 100E20 (manufactured by Toray Industries, Inc.) as a film substrate, a palladium film having a thickness of 10 nm is formed on one surface of the film substrate using a magnetron sputtering apparatus, and a metallized film is formed. Created. As the target, palladium having a purity of 99.9% (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was used. Argon was used as the sputtering gas. The center line average roughness (Ra) of the outermost metal layer was 100 nm. The surface resistance value was maintained at the same value as that immediately after metal lamination even after being left in the air for 15 minutes. However, the liquid spreadability was good immediately after metal lamination, but became poor after being left in the atmosphere for 15 minutes. The stability of the surface resistance value was good, with the amount of change in resistance value after standing for 15 minutes in the air immediately after metal lamination being less than 5Ω / □. Further, the difference between the maximum value and the minimum value of the surface resistance value was less than 20Ω / □, and the uniformity of the surface resistance value with respect to the measurement position was good.

[Comparative Example 2]
A 100 μm polyester film 100T60 (manufactured by Toray Industries, Inc.) is used as a film base, and a palladium film having a thickness of 10 nm is formed on one surface of the film base using a magnetron sputtering apparatus. A metallized film was prepared by forming a 10 nm gold film on the palladium film. The target is gold of 99.99% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a gold film, and palladium of 99.9% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a palladium film. Was used. Argon was used as the sputtering gas. The center line average roughness (Ra) of the outermost metal layer was 3 nm. The surface resistance value was maintained at the same value as that immediately after metal lamination even after being left in the air for 15 minutes. However, the liquid developability was poor both after the metal lamination and after being left in the atmosphere for 15 minutes. The stability of the surface resistance value was good, with the amount of change in resistance value after standing for 15 minutes in the air immediately after metal lamination being less than 5Ω / □. Further, the difference between the maximum value and the minimum value of the surface resistance value was less than 20Ω / □, and the uniformity of the surface resistance value with respect to the measurement position was good.

[Comparative Example 3]
A 100 μm polyester film 100E20 (manufactured by Toray Industries, Inc.) was used as the film substrate, and after corona discharge treatment was performed on the film substrate in the air, a palladium film having a thickness of 10 nm was formed using a magnetron sputtering apparatus. A metallized film was formed by forming on one surface of the film substrate and further forming a 10 nm thick gold film on the palladium film. The target is gold of 99.99% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a gold film, and palladium of 99.9% purity (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) for the production of a palladium film. Was used. Argon was used as the sputtering gas. The treatment time for the corona discharge was adjusted so that the center line average roughness (Ra) of the outermost metal layer was 200 nm. The liquid spreadability was good both immediately after metal lamination and after being left in the atmosphere for 15 minutes. The stability of the surface resistance value was good, with the amount of change in resistance value after standing for 15 minutes in the air immediately after metal lamination being less than 5Ω / □. However, the difference between the maximum value and the minimum value of the surface resistance value was 30Ω / □, and the uniformity of the surface resistance value with respect to the measurement position was poor.

  The present invention is particularly preferably used as a metallized film used as an electrode for measuring a potential change caused by a chemical reaction occurring via a substance coated on a metallized film, or a current.

It is a side view which shows one embodiment of the metallized film of this invention. It is a side view which shows one embodiment of the metallized film of this invention.

Explanation of symbols

1: Polymer film substrate 2: Metal layer composed of gold and / or platinum 3: Metal layer

Claims (7)

  A metallized film in which one or more metal layers are laminated on a polymer film substrate, the outermost layer being a metal layer composed of gold and / or platinum, and the center of the outermost metal layer surface A metallized film having a line average roughness (Ra) of 5 to 150 nm.   The metallized film according to claim 1, wherein the polymer film is a polyester film.   The metallized film according to claim 1 or 2, wherein the polymer film has been surface-treated.   The metallized film according to claim 3, wherein the surface treatment is corona discharge treatment, glow discharge treatment, flame treatment, etching treatment, or roughening treatment.   The metallized film according to any one of claims 1 to 4, wherein the polymer film is surface-coated.   6. The surface coating according to claim 5, wherein at least one selected from a polyurethane resin, a polyester resin, a polyester acrylate resin, a polyurethane acrylate resin, a polyepoxy acrylate resin, and a titanate compound is applied. Metallized film.   The metallized film according to any one of claims 1 to 6, wherein the metallized film is for an electrode constituting an in vitro diagnostic cell used in a test kit.

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