JP4539253B2 - Method for producing palladium film roll - Google Patents

Description

  The present invention relates to a method for producing a palladium film roll in which a palladium thin film is formed on a plastic film surface. The palladium film manufactured by the method for manufacturing a palladium film roll of the present invention exhibits stable surface wettability and can be preferably used for purposes such as electrodes and terminals.

  Palladium is known as a plating material having excellent characteristics like gold. Palladium is excellent as a plating material for connector contacts, electrodes, and the like because it is hard and excellent in wear resistance and corrosion resistance, and is unlikely to cause surface discoloration that easily occurs with silver or the like. Since palladium has good adhesion to a plastic film, a palladium film in which palladium is formed on a plastic film is used for a flexible printed wiring board (see Patent Document 1) or as an electrode film for a film capacitor. (See Patent Document 2). Further, in recent years, the use of palladium films has expanded, and it has come to be preferably used for electrodes for chemical sensors.

  By the way, when palladium is deposited on a film in a vacuum and then exposed to air, the wettability of the surface tends to change over time. As can be inferred from the fact that palladium is used as various catalysts, it is considered that a clean palladium surface is very active and the surface state is very easily changed by the influence of oxidation, adsorption and the like.

  However, when there is a step of dropping or applying droplets on the palladium surface, controlling the wettability of the palladium surface to an appropriate state is very important for improving the yield of products. For example, when a palladium film is used as an electrode material in a chemical sensor or the like, there is a step of coating a reagent layer on a part of the surface of the palladium layer, but if the wettability is too good, that is, the contact angle is too small, the reagent layer It spreads too much on the palladium surface, making it difficult to form a reagent layer on a specific part of the electrode surface. Conversely, if the wettability is too bad, that is, the contact angle is too large, the reagent layer is spherical and does not spread on the palladium surface, and in this case as well, it is difficult to form the reagent layer on a specific part of the electrode surface, Not suitable as an electrode material.

  Immediately after the palladium layer is formed on the film in vacuum, the wettability is very good, and the contact angle of pure water is 20 degrees or less. For this reason, it cannot be used as an electrode material in which a reagent layer is provided at a specific portion for the above reasons. However, since the palladium surface is very active, the contact angle of pure water increases over time when exposed to air.

  For this reason, it is necessary to let the palladium surface come into contact with air until the wettability becomes appropriate. As a technique for this purpose, a method is known in which the humidity in the atmosphere and the time of exposure to the atmosphere are defined (see Patent Document 3).

However, even with this method, the activity of the palladium surface is still high. For example, when the contact angle of pure water is measured, the contact angle changes greatly over time, and the wettability of the surface cannot be defined. It has been found that there are cases in which the change in property is too large to be used easily, and the intended wettability may not be achieved.
JP-A-5-299820 JP-A-5-275276 Japanese Patent Application No. 2003-132676

  In the palladium film collected from the palladium film roll, the present invention sets the wettability to an appropriate level, suppresses the rate of change of wettability over time, and applies a chemical solution to the palladium surface. It is an object that stable processing can be performed when performing.

  As a result of intensive studies to solve the above-mentioned problems, the film was wound into a roll while forming a palladium thin film on a plastic film by a vacuum thin film forming method, and then the first rewinding was performed in the atmosphere within 720 hours. Provided is a method for producing a palladium film roll, which is rewound in the atmosphere at least once.

  According to the present invention, it is possible to provide a palladium film having a palladium surface that exhibits a target surface wettability and exhibits a stable wettability with a small rate of change in wettability over time. Stable processing can be performed when performing.

  In the method for producing a palladium film roll according to the present invention, first, a palladium thin film is formed on a plastic film in a vacuum chamber having a pressure of 10 Pa or less, and then wound into a roll shape.

  As the plastic film, any film can be selected according to the purpose of use. Polyester film, polycarbonate film, cellulose film, polyolefin film, acrylic film, polyamide film, polyimide film, polyvinyl chloride film, polysulfone film, polystyrene film, fluorine film, etc. However, a polyester film is preferably used from the viewpoint of mechanical strength and heat resistance stability, and a polyethylene terephthalate film can be preferably used from the viewpoint of price and supply stability. A film thickness in the range of 9 to 250 μm can be used. The film may be transparent or colored.

  The palladium thin film can be formed by a normal vacuum vapor deposition method, but it is preferably formed by sputtering because the film thickness can be controlled with high accuracy and a noble metal called palladium can be used efficiently. The method of sputtering is not particularly limited, and normal DC magnetron sputtering, DC pulse magnetron sputtering, high frequency magnetron sputtering in which an alternating current of about several tens of kHz is applied to adjacent magnetron targets can be arbitrarily selected. .

  The thickness of the palladium thin film is determined by the target surface resistance value, but usually a thickness of several nm to several tens of nm is selected, and the surface resistance value ranges from several Ω / □ to several hundred Ω / □. It is common to do. The surface resistance value of the palladium film is preferably formed while passing through a four-terminal resistance measurement roll during film formation or in-line using a non-contact resistance measurement system using the eddy current principle. . The surface resistance value of the formed palladium film can be measured by a general surface resistance measuring device using a four-terminal method.

  In the method for producing a palladium film roll of the present invention, palladium is continuously formed while winding the film in a roll in a vacuum chamber in order to prevent the formed palladium from directly contacting the air.

  If the exhaust of the vacuum chamber is insufficient, there may be a problem that palladium is oxidized by residual gas such as water and the resistance value is increased. In particular, since the moisture contained in the film may have an adverse effect, it is preferable to exhaust the gas sufficiently.

As an example of the method for producing a palladium film roll of the present invention, a palladium thin film is formed by sputtering with argon gas introduced into a vacuum chamber evacuated to a pressure of 1 × 10 ⁻² Pa or less and using palladium metal as a target. Is done.

  Immediately after the palladium thin film is formed on the film, the wettability is very high, and when a droplet is dropped, problems such as the liquid spreading too much occur. Generally, the wettability of a palladium film can be evaluated by dropping pure water on the palladium surface and measuring the contact angle. The pure water contact angle on the surface of the palladium after the rewinding is set to a target value according to the processing applied on the surface, but if the pure water contact angle is in the range of 35 to 55 degrees, it is appropriate. It becomes a wettable palladium film.

  Since the wettability of the palladium surface is reduced by touching air, the wettability can be controlled to an appropriate level by rolling back so as to touch the air for a certain period of time.

  In the method for producing a palladium film roll of the present invention, in order to obtain a palladium film having a moderate wettability on the surface, it is necessary to first wrap in the atmosphere within 720 hours after forming the palladium thin film. .

  When the elapsed time from the formation of the palladium thin film to the rewinding exceeds 720 hours, the pure water contact angle after the rewinding is very small, and the contact angle does not increase even after the second rewinding, and the wettability is extremely high. The palladium film having a very high pure water contact angle. In order to obtain the target wettability, it is more preferable to perform the first rewinding within 360 hours as the elapsed time until the rewinding.

  Immediately after the first rewinding, there is a problem that the wettability of the palladium surface changes greatly with time. In other words, when the film is pulled out from the film roll and the pure water contact angle is measured, the pure water contact angle changes every moment in the same time as the time required for measurement, and it is extremely difficult to accurately evaluate the wettability of the product. It becomes. Actually, it takes 30 seconds to 1 minute to measure the contact angle of pure water, but the contact angle changes immediately after the film is pulled out from the film roll, and the film is collected and set in a measuring instrument. The phenomenon that the pure water contact angle continues to change greatly before the measurement is started occurs.

  In the method for producing a palladium film roll of the present invention, after the first rewinding in the air, the rewinding is further performed one or more times, and the change in the pure water contact angle with time is less than 0.65 degrees / min. It is important to keep it down. It is preferable that the time change rate of the pure water contact angle is 0.5 degrees / min or less by the second and subsequent rewinding. More preferably, the palladium film having stable surface wettability can be obtained by setting the rate to 0.4 degrees / minute.

  The time from the first rewinding to the second and subsequent rewinding is preferably 6 hours or more. In the case of rewinding in less than 6 hours, the temporal change rate of the pure water contact angle may still be large. It is more preferable that 12 hours or more elapse to obtain more stable surface wettability.

  After performing the second rewinding, the pure water contact angle on the palladium surface is measured, and when the contact angle is small, the third and subsequent rewinding is further performed to further increase the pure water contact angle. It is also possible to adjust the wettability of the surface.

  In the method for producing a palladium film roll of the present invention, the palladium film roll before rewinding may be stored in a vacuum or in the air. When storing in the air, the entire roll is preferably made of a highly moisture-proof material and sealed with a desiccant.

  In the method for producing a palladium film of the present invention, it is preferable to control the wettability of the palladium surface after rewinding according to the time during which it is exposed to air after being unwound and wound. The time of exposure to air by rewinding is preferably adjusted by the pass line length from roll feeding to winding and the film winding speed. In addition, since moisture in the air affects the change in wettability, it is also preferable to control the wettability of the surface by rewinding in a room with adjusted humidity. The humidity in the room to be rolled back is preferably adjusted by a humidifier or a dehumidifier.

  In the method for producing a palladium film of the present invention, the film may be rolled while being slit to a width suitable for use, or may be wound while blowing air with a blower in order to remove foreign matter attached to the surface. In particular, it is preferable to blow moderately conditioned air because the change in wettability of the palladium surface is promoted and the wettability can be controlled in a short time.

  In the method for producing a palladium film roll of the present invention, the film roll after rewinding is packed with a moisture-proof film together with a desiccant, so that a so-called moisture-proof packaging is applied, in order to maintain stable wetting characteristics of the palladium surface. preferable. If moisture-proof packaging is not performed, the pure water contact angle at the end of the film is greatly increased by moisture entering from the end of the film roll, and the intended wettability may not be achieved.

  The palladium film manufactured by the method for manufacturing a palladium film roll of the present invention has appropriate wettability and can maintain appropriate wettability for a long period of time as long as it is packed by an appropriate method. The palladium film produced by the method for producing a palladium film of the present invention has a certain size reagent by dripping or coating the liquid on a part of the surface of the electrode on which the palladium is formed, because the dropped liquid spreads moderately. When a layer is provided, stable processing is possible.

  Next, the manufacturing method of the palladium film roll of this invention is demonstrated with an Example and a comparative example. The film evaluation method is as follows.

(1) First pure water contact angle (degrees)
Using a contact angle meter CA-X manufactured by Kyowa Interface Science Co., Ltd., 1.6 mg of pure water was added dropwise to measure the contact angle. The measurement was performed 10 times at 30-second intervals after the measurement film was collected from the roll, and attention was paid to the first pure water contact angle.

(2) Time change rate of pure water contact angle (degrees / minute)
The rate of change over time was calculated by performing linear approximation from the 10 measurement results.

Example 1
A palladium thin film was continuously formed on the film by a sputtering method while winding a polyester film ("Lumirror" T60 manufactured by Toray Industries, Inc.) having a thickness of 188 µm and a width of 1000 mm in a vacuum chamber. Two palladium metal targets of 100 mm × 1700 mm were used as targets, and a 40 kHz high frequency magnetron sputtering method was used. Sputtering was performed with an input power of 10 kW and a flow rate of 5 m / min in a state where argon gas was flown into the vacuum chamber evacuated until the pressure became 5 × 10 ⁻³ Pa or less. The finished palladium film had a surface resistance of 80Ω / □.

  The film roll wound with the palladium thin film formed is taken out from the vacuum chamber, and the entire roll is made of aluminum-deposited polyester film (“Metal Me” manufactured by Toyo Metallizing Co., Ltd.) and 4 desiccants (“Ode Chemical” “Decipack”) And after moisture-proof packaging and storing for 72 hours, it was rolled back in air | atmosphere, without slitting with a slit apparatus. The pass line from the roll on the feeding side to the roll on the winding side was 13 m, and the film was rewound at a speed of 6 m / min. The room for rewinding was adjusted so that the temperature was 21 ° C. and the relative humidity was 50%.

  After completing the first rewinding, the same moisture-proof packaging as described above was applied, and after storing for 24 hours, the second rewinding was performed at a speed of 6 m / min while three slits were made in a width of 300 mm. The temperature and humidity during the second rewinding were the same as those for the first rewinding.

  Immediately after the second rewinding, the wettability of the palladium surface was evaluated.

  As a result of the first measurement, the time change rate of the pure water contact angle by the measurement of 39.6 degrees and 10 times was 0.34 degrees / minute, and a stable surface wetting characteristic was obtained.

  Moreover, this roll was packaged with an aluminum vapor-deposited polyester film together with a desiccant, and further wrapped with a laminated sheet of an aluminum vapor-deposited film and linear low-density polyethylene in a tube shape to perform moisture-proof packaging. After 720 hours passed in this state, the film was sampled and measured for 9 pure water contact angles at 30 mm intervals in the width direction of 300 mm. All 9 points were in the range of 41.0 ± 1.0 degrees. And surface wettability with extremely uniform characteristics.

  When the roll was stored for 720 hours under the conditions of 25 ° C. and 50% RH without performing such moisture-proof packaging, the central 7 points were in the range of 41 ° to 43 °, but both ends were 44.degree. It was 8 degrees and 44.6 degrees, and was affected by the intrusion of humidity from the end.

Example 2
A palladium film was produced under the same conditions as in Example 1 except that the time from the formation of the palladium thin film to the first rewinding was 12 hours.

  The first measured value of the pure water contact angle was 42.8 degrees, and the temporal change rate of the pure water contact angle was 0.56 degrees / minute.

Example 3
A palladium film was produced under the same conditions as in Example 1 except that the time from the formation of the palladium thin film to the first rewinding was 240 hours.

  The first measured value of the pure water contact angle was 36.8 degrees, and the temporal change rate of the pure water contact angle was 0.25 degrees / minute.

Example 4
A palladium film was produced under the same conditions as in Example 1 except that the time from the formation of the palladium thin film to the first rewinding was 480 hours.

  The first measured value of the pure water contact angle was 35.7 degrees, and the temporal change rate of the pure water contact angle was 0.22 degrees / minute.

Comparative Example 1
A palladium film was produced under the same conditions as in Example 1 except that the time from the formation of the palladium thin film to the first rewinding was 960 hours.

  The first measured value of the pure water contact angle was 28.0 degrees, and the time change rate of the pure water contact angle was 0.20 degrees / minute.

Comparative Example 2
When the pure water contact angle was measured after the first rewinding of Example 1 without performing the second rewinding, the first measured value was 35.4 degrees, and the time change rate of the pure water contact angle was 0.00. The contact angle with pure water changed greatly during the measurement, being as large as 65 degrees / minute.

Example 5
A palladium film was produced under the same conditions as in Example 1 except that the time from the first rewinding operation to the second execution was 3 hours.

  The first measured value of the pure water contact angle was 38.3 degrees, but the temporal change rate of the pure water contact angle was a little as large as 0.47 degrees / minute.

Example 6
After the second rewinding of Example 5, 12 hours later, the rewinding was performed under the same conditions. The first measured value of the pure water contact angle was 43.9 °, the time change rate of the pure water contact angle was 0.18 ° / min, and the surface wettability was stabilized.

  These results are summarized in Table 1.

  As is apparent from Table 1, according to the examples of the present invention, a palladium film that exhibits moderate wettability, has a small change rate with time of pure water contact angle, and exhibits stable surface wettability can be obtained. .

Claims (4)

Palladium is characterized in that it is wound up in a roll while forming a palladium thin film on a plastic film by a vacuum thin film forming method, and then rewound in the atmosphere for the first time within 720 hours, and further rewound in the atmosphere at least once. Film roll manufacturing method. 2. The method for producing a palladium film roll according to claim 1, wherein the temporal change rate of the pure water contact angle on the palladium surface after being wound twice or more is 0.5 degrees / min or less. The method for producing a palladium film roll according to claim 1 or 2, wherein the second and subsequent rewinding is performed after 6 hours or more have elapsed since the first rewinding. Method for producing a palladium film roll according to any of claims 1 to 3, characterized by packing the palladium film roll after rewinding a film having a moisture-proof with desiccant.