JPWO2009144973A1 - Sn or Sn alloy plating film, composite material having the same, and method for producing composite material - Google Patents

Abstract

Provided are a Sn or Sn alloy plating film which is excellent in roll maintainability and can improve productivity by preventing the Sn or Sn alloy plating film from sliding or falling off, and a composite material having the Sn or Sn alloy plating film. . SOLUTION: An Sn or Sn alloy having a hardness of 500 MPa or less, formed from an Sn or Sn alloy electroplating bath not containing methanol on the other surface of a copper foil or copper alloy foil 1 on which a resin layer or a film 4 is laminated. When the surface of the Sn or Sn alloy plating film is observed with a scanning electron microscope in the case of the plating film 2 (however, when the thickness of the Sn or Sn alloy plating film exceeds 1.5 μm, the thickness of the Sn or Sn alloy plating film) ) Is not exposed to copper foil or copper alloy foil. [Selection] Figure 1

Description

  The present invention relates to an Sn or Sn alloy plating film formed on the other surface of a copper foil or a copper alloy foil laminated with a resin or the like, used for an electromagnetic wave shielding material or the like, a composite material having the same, and a method for producing the composite material About.

The Sn plating film is characterized by excellent corrosion resistance, good solderability and low contact resistance. For this reason, for example, Sn plating is used for metal foils, such as copper, as a composite material of a vehicle-mounted electromagnetic wave shielding material.
As the above composite material, as a composite material such as an electromagnetic shielding material based on copper or copper alloy foil, a resin layer or a film is laminated on one surface of copper foil or copper alloy foil, and Sn is formed on the other surface. A structure in which a plating film is formed is used.
In recent years, in applications such as connectors, it has been desired that the Sn plating film be hardened from the viewpoint of wear resistance and insertion / removability, and a technique for defining the Knoop hardness Hk of the Sn plating surface layer has been disclosed (patent). Reference 1).

Sn plating on copper or copper alloy foil is usually performed by wet plating, but in order to improve the stability of the plating film (the color must be uniform and free of color spots and patterns) and the wear resistance of the Sn plating film In many cases, bright Sn plating is performed by adding an additive to the plating solution.
For example, a technique is disclosed in which a brightening agent is added to a plating solution to perform bright Sn plating to make Sn particles as small as possible (see Patent Document 2).
On the other hand, whisker-like crystals called whiskers are generated in Sn plating due to internal stress and external stress. In order to prevent this, it is known that the internal stress is reduced by extremely reducing the brightening agent during plating. However, it is difficult to prevent whisker generation due to external stress even by this method. For this reason, a technique has been disclosed in which the brightener in the electroplating bath is reduced and methanol is added to create a void in the Sn plating film to relieve external stress generated by bending or punching after plating. . (See Patent Document 3)

JP 2002-298963 A Japanese Patent No. 3007207 JP 2007-254860 JP

However, when hard Sn plating (for example, normal bright Sn plating) is performed on a metal foil such as copper or copper alloy foil in a continuous line, there is a problem that the surface of the Sn plating is rubbed and transferred and adhered to the roll. When plating adheres to the roll surface, the productivity during plating is reduced by cleaning the roll, etc., and when the adhesion of plating is extremely severe, the Sn plating film becomes thin, leading to a reduction in the corrosion resistance of the resulting composite material. This is a problem that cannot be ignored because there is a fear.
The reason why such a defect occurs is unknown, but in the case of terminals, connectors, etc., the harder the Sn plating, the better the insertion / extraction, so the harder the Sn plating, the better the slipperiness between the Sn contact surfaces. It is possible. That is, when the Sn plating is hard, slippage between the roll and the Sn plating surface on the metal foil is likely to occur, and if slip begins to occur, the Sn plating tends to adhere to the roll due to frictional heat or the like. It is thought that adhesion is seen.
It is also conceivable that the organic material of the brightener co-deposits on the Sn coating, making the plating brittle and easy to fall off.

Furthermore, when passing a metal foil through a continuous line, it is considered that the above-described slip is more likely to occur. That is, since the copper foil is thin, its strength is low, and folding and wrinkling are likely to occur when passing through a continuous line such as Sn plating, laminator, and slitter. Therefore, when used as a shielding material, it is common to first paste a resin or film on a copper foil and then perform Sn plating, but even a copper foil with such a resin or film attached When the tension applied to the strip is increased during continuous line passing, folding and wrinkles are likely to occur. Therefore, in order to stably prevent the occurrence of folds and wrinkles, it is desirable to pass the plate with a low tension. On the other hand, when the tension applied to the strip decreases, the contact pressure between the roll and the strip decreases, and the roll And slip easily between strips. Therefore, the adhesion of Sn plating is more likely to occur.
Such adhesion of Sn plating is the same when there is a continuous process using a roll after the plating process. For example, this is the process of slitting the strip to the desired width after Sn plating.

  Moreover, when using the composite material obtained by Sn-plating copper foil for electromagnetic shielding materials, such as a cable, a composite material is wound around cable outer periphery, and also the resin is coat | covered on the outer side. In this resin coating process, if a composite material in which Sn plating easily adheres to the line as described above is used, when the composite material passes through a die (die), the Sn plating film tends to fall off, and the Sn residue is removed from the die. There is a high possibility of adhesion. And if Sn residue adheres to the die, time is required for maintenance, and productivity is lowered.

On the other hand, Patent Document 3 describes that the hardness of the Sn plating film is 400 MPa or less in order to make it less susceptible to external stress. However, the technique described in Patent Document 3 is a plating film with many voids because it contains a high concentration of methanol in the plating bath, and if the electrolysis is continued for a long time, a large defect (exposure of the ground) occurs in the Sn plating film. It has been clarified by the inventors' investigation.
This is presumably because methanol in the plating bath is converted into formaldehyde by electrolysis, which inhibits normal Sn deposition and causes defects in the plating film. And if the foundation | substrate is exposed, the malfunction which the corrosion resistance of a foundation | substrate (metal foil) falls will arise.

  The present invention has been made to solve the above-described problems, and prevents Sn or Sn alloy plating film from being slid or dropped during plating or use, thereby improving productivity and being excellent in corrosion resistance. Alternatively, an object is to provide a Sn alloy plating film and a composite material having the same.

  As a result of various studies, the present inventors reduced the sliding or falling off of the Sn or Sn alloy plating film by setting the hardness of the Sn or Sn alloy plating film on the surface of the copper or copper alloy foil to a predetermined hardness or less. Succeeded in doing. In addition, by electroplating using a plating bath not containing methanol, the exposure of the substrate due to defects in the plating film was suppressed, and the corrosion resistance was also successfully improved.

  In order to achieve the above object, the Sn or Sn alloy plating film of the present invention is a Sn or Sn alloy electroplating bath not containing methanol on the other surface of the copper foil or copper alloy foil in which the resin layer or film is laminated. When the surface of the Sn or Sn alloy plating film is observed with a scanning electron microscope (however, the thickness of the Sn or Sn alloy plating film is When the thickness exceeds 1.5 μm, when the thickness of the Sn or Sn alloy plating film is reduced to 1.5 μm), the copper foil or copper alloy foil is not exposed.

Furthermore, it is preferable that the carbon content in the Sn or Sn alloy plating film is 0.01% by mass or less.
The thickness of the Sn or Sn alloy plating film is preferably 0.5 μm or more. Moreover, it is preferable that the thickness of Sn or Sn alloy plating film is less than 2.0 micrometers.
The Sn or Sn alloy plating film is preferably formed by continuous plating.

  The composite material of the present invention is formed on a copper foil or copper alloy foil, a resin layer or film laminated on one surface of the copper foil or copper alloy foil, and the other surface of the copper foil or copper alloy foil. And the Sn or Sn alloy plating film.

  The thickness of the composite material is preferably 0.1 mm or less, and is preferably used for an electromagnetic wave shield.

In the present invention, the Sn plating hardness is an indentation hardness with a maximum load of 1 mN in an ultra-micro hardness test measured in accordance with ISO 14577-1 2002-10-01 Part 1. Details of the measurement method will be described later.
In the present invention, when the surface of the Sn or Sn alloy plating film is observed with a scanning electron microscope, “the copper foil or copper alloy foil is not exposed” means that the reflected electron image of the Sn or Sn alloy plating film has a luminance different from that of the reflected electron image. It means that an electron image is not observed at a normal magnification (for example, about 1000 times), and a reflected electron image having a uniform luminance is obtained.
The thickness of the Sn or Sn alloy plating film is an average macro thickness of the Sn or Sn alloy plating film, and is obtained from the amount of electricity when the plating film is electrolyzed and completely dissolved.
Moreover, the carbon content analysis method in Sn plating film can be performed using the high frequency induction heating infrared absorption method. In this method, a Sn-plated sample is heated and dissolved in an oxygen atmosphere, carbon in the sample is reacted with oxygen in the atmosphere, and the amount of carbon dioxide in the atmosphere is measured to calculate the amount of carbon. The amount of carbon in the Sn plating film is determined by the difference from the sample with the Sn plating film, with the sample (plating base material) from which the plating film has been removed beforehand being used as a blank.

  ADVANTAGE OF THE INVENTION According to this invention, the Sn plating film which can be excellent in the maintainability of a roll and can improve productivity by preventing a Sn plating film from sliding and dropping, and a composite material having the same are obtained.

  Embodiments of the present invention will be described below. In the present invention, “%” means “% by mass” unless otherwise specified.

The composite material which concerns on embodiment of this invention is the copper foil (or copper alloy foil) 1, the resin layer (or film) 4 laminated | stacked on one surface of the copper foil (or copper alloy foil) 1, and copper It consists of Sn plating film 2 formed in the other surface of foil (or copper alloy foil) 1.
From the viewpoint of lightening the material, the thickness of the composite material is preferably 0.1 mm or less.

As the copper foil, tough pitch copper having a purity of 99.9% or more, oxygen-free copper, and as the copper alloy foil, a known copper alloy can be used depending on required strength and conductivity. Known copper alloys include, for example, 0.01 to 0.3% tin-containing copper alloys and 0.01 to 0.05% silver-containing copper alloys. -0.12% Sn and Cu-0.02% Ag are often used.
The thickness of the copper foil (or copper alloy foil) is not particularly limited, but when used as a shielding material, for example, a thickness of 5 to 50 μm can be suitably used.
In addition, as copper foil (or copper alloy foil), it is preferable to use a rolled foil having higher strength than electrolytic foil.
Further, the surface roughness of the copper foil (or copper alloy foil) is preferably 0.3 μm or less, more preferably 0.2 μm or less in terms of centerline average roughness when the thickness is 5 to 50 μm.

As the resin layer, for example, a resin such as polyimide can be used, and as the film, for example, a film of PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) can be used. The resin layer or film may be bonded to the copper foil (or copper alloy foil) with an adhesive, but the molten resin is cast on the copper foil (copper alloy foil) without using the adhesive, or the film is made of copper. You may make it thermocompression-bond to foil (copper alloy foil).
The thickness of the resin layer or film is not particularly limited, but for example, a thickness of 5 to 50 μm can be suitably used. When an adhesive is used, the thickness of the adhesive layer can be set to 10 μm or less, for example.

  For example, Sn—Cu, Sn—Ag, or Sn—Pb can be used as the Sn alloy plating film.

In the present invention, the Sn or Sn alloy plating film is formed from an Sn or Sn alloy electroplating bath not containing methanol. When methanol is contained in the plating bath, defects (exposure of the base) occur in the plating film when electrolysis is continued for a long time.
This is presumably because methanol in the plating bath is converted into formaldehyde by electrolysis, which inhibits normal Sn deposition and causes defects in the plating film. And when a foundation | substrate is exposed, the malfunction which the corrosion resistance of a foundation | substrate (copper foil or copper alloy foil) falls arises. The electrolysis time for giving defects to the plating film varies depending on the plating conditions, but as the total electrolysis time increases, the formaldehyde in which methanol has changed accumulates in the plating bath, and plating defects that expose the substrate are more likely to occur. .
Note that “not containing methanol” in the plating bath means that the methanol concentration in the plating bath is at an impurity level (usually several ppm (several mg / L) or less, for example, 5 mg / L or less).

By plating using a Sn or Sn alloy electroplating bath that does not contain methanol, when the surface of the plating film is observed with a scanning electron microscope, the base (copper foil or copper alloy foil) is not exposed, and there is no defect. A film is obtained. In this case, when the surface of the plating film is observed with a scanning electron microscope, a reflected electron image having a luminance different from that of the reflected electron image of the plating film is not observed at a normal magnification (for example, about 1000 times). An electronic image is obtained. That is, the composition different from the plating film is not detected from the surface of the plating film, and the base (copper foil or copper alloy foil) is not exposed.
If the thickness of the Sn or Sn alloy plating film exceeds 1.5 μm, coarse plating grains may cover the exposed part of the base (plating defect part) (however, the base is completely covered). However, when the surface of the plating film is observed with a scanning electron microscope, the reflected electron image of the ground which should be exposed may not be obtained. Also in this case, since the base is actually exposed and the corrosion resistance is inferior, in order to accurately determine whether the base is exposed or not, the thickness of the plating film is reduced to 1.5 μm and observed with a scanning electron microscope.
As a method of reducing the thickness of the plating film to 1.5 μm, a method of producing a cross section of the plating film by FIB (focused ion beam), or a plating metal (or alloy) for reducing the thickness of the plating film to 1.5 μm. There is a method in which the amount of electricity at the time of electrolysis is set so that the amount of dissolution when electrolyzing the plating film coincides with this amount of reduction.

  The thickness of the Sn or Sn alloy plating film is an average macro thickness of the Sn or Sn alloy plating film, and is obtained from the amount of electricity when the plating film is electrolyzed and completely dissolved.

The hardness of the Sn or Sn alloy plating film is 500 MPa or less. When the hardness of the Sn or Sn alloy plating film is 500 MPa or less, slip between the Sn or Sn alloy plating surface and the roll is reduced during Sn or Sn alloy plating, and the adhesion of Sn or Sn alloy plating is lost. Further, when the obtained composite material is used for an electromagnetic shielding material such as a cable, the adhesion of Sn or Sn alloy to the roll or die during processing is not seen, and the productivity can be improved. And when processing the obtained composite material, the powder fall of Sn or Sn alloy plating film does not arise, and adhesiveness does not fall.
There is no reason to specifically limit the lower limit of the plating hardness of the Sn or Sn alloy plating film, but it cannot be less than the hardness of the melted and solidified Sn or Sn alloy. In the present invention, the lower limit is 100 MPa.

Further, the carbon content in the Sn or Sn alloy plating film is preferably 0.01% by mass or less, and more preferably 0.006% by mass or less. If the amount of carbon in the Sn or Sn alloy plating film exceeds 0.01% by mass, even if the Sn plating film has a hardness of 500 MPa or less, the film is brittle and Sn tends to adhere to the roll.
Moreover, the carbon content analysis method in Sn or Sn alloy plating film can be performed using the high frequency induction heating infrared absorption method. In this method, a sample plated with Sn or Sn alloy is heated and dissolved in an oxygen atmosphere, the carbon in the sample is reacted with oxygen in the atmosphere, and the amount of carbon dioxide in the atmosphere is measured to calculate the amount of carbon. . The amount of carbon in the Sn or Sn alloy plating film is determined by the difference from the sample with the Sn or Sn alloy plating film, with the sample (plating base material) from which the plating film has been removed beforehand being used as a blank.

The thickness of the Sn or Sn alloy plating film is preferably 0.5 μm or more. When the thickness is less than 0.5 μm, the corrosion resistance and solderability may deteriorate.
The upper limit of the thickness of the Sn or Sn alloy plating film is not particularly limited because it varies depending on the manufacturing conditions of the Sn or Sn alloy plating, etc. Even if the Sn or Sn alloy plating is thickened to 2 μm or more, the corrosion resistance and solderability are further improved. However, there are also problems such as increasing the Sn or Sn alloy plating allowance and reducing productivity. Therefore, it is preferable that the thickness of the Sn plating film is 0.5 μm or more and less than 2 μm.

The hardness of the Sn or Sn alloy plating film is an indentation hardness with a maximum load of 1 mN in an ultra micro hardness test measured in accordance with ISO (International Organization for Standardization) 14477-1 2002-10-01 Part 1. The measuring instrument used for this measurement is not limited as long as it can be measured in accordance with ISO 14577-1 2002-10-01 Part1, but for example, ENT-2100 made by Elionix can be used, and Berkovich indenter ( Diamond triangular pyramid indenter) can be used. Moreover, in this invention, the measurement conditions of indentation hardness are as follows.
Test mode: Load-unloading test (unload after pushing to maximum load)
Maximum load: 1mN
Measurement temperature: 32 ± 1 ℃
The hardness value is an average value of five locations.
The indentation hardness that can be measured by this method is affected by the film thickness. That is, the thicker the film, the harder the film itself, and the thinner the film, the lower the influence of the hardness of the intermetallic compound of Cu or Cu-Sn, which is the base metal. However, what is a problem in the present invention is the “apparent hardness” of the surface layer, and when this is measured softly, it does not slip with the roll. As the index, the result of hardness measurement under the above conditions is effective.
The thickness of the plating film is measured with a fluorescent X-ray film thickness meter, and the average value of the five points is defined as the thickness of the plating layer.

  As a method of setting the hardness of the Sn or Sn alloy plating film to 500 MPa or less, for example, it can be performed by controlling the electrodeposited grains (increasing the electrodeposited grains). The size of the electrodeposited grains depends on the plating conditions such as current density, Sn concentration and bath temperature, or in the Sn or Sn alloy plating bath, brighteners (for example, aldehyde, imidazole, benzal acetone, etc. are commercially available. Can be controlled by not adding to the plating bath.

  Furthermore, embrittlement of the Sn or Sn alloy plating film can be prevented by controlling the carbon amount in the Sn or Sn alloy plating film (reducing the carbon amount). The method for reducing the amount of carbon in the Sn or Sn alloy plating film can be controlled, for example, by reducing the addition of chemicals made of organic compounds (for example, brighteners) to the plating bath. However, a naphthol surfactant such as EN (ethoxylated naphthol) may be added to the Sn or Sn alloy plating bath. Further, a nonionic surfactant such as ENSA (ethoxylated naphthol sulfonic acid), polyethylene glycol, or polyethylene glycol nonylphenol ether may be added to the Sn or Sn alloy plating bath. In addition to the surfactant, an organic substance such as naphthol having a low gloss effect may be added.

A more specific method will be described below.
Examples of the base of the Sn or Sn alloy plating bath include phenolsulfonic acid, sulfuric acid, methanesulfonic acid and the like.
The size of the electrodeposited grains can be adjusted by reducing the current density, increasing the Sn concentration in the bath, and increasing the bath temperature under plating conditions. For example, when the current density is ^{2 to} 12 A / dm ² , the Sn concentration is 30 to 60 g / L, and the bath temperature is 30 to 60 ° C., the electrodeposition of granular electrodeposited Sn (or Sn alloy) can be uniformly electrodeposited on the copper foil surface. Yes, but it is not particularly limited because it varies depending on the device.
Further, the amount of carbon in the Sn or Sn alloy plating film varies depending on the type of brightener, the type of surfactant, and the plating conditions. Most brighteners increase the amount of carbon in the Sn or Sn alloy plating film and often exceed 0.01% by weight. However, in some cases, the amount of carbon in the coating can be reduced by adding very little brightener, reducing the current density under plating conditions, increasing the Sn concentration, and increasing the temperature.
When only a surfactant is added to the plating solution, the amount of carbon in the coating is often 0.01% by mass or less. However, if the amount of the surfactant added to the plating solution is large, or if the surfactant has a structure that is easily adsorbed to Sn, the amount of carbon in the coating increases. Therefore, the surfactant is appropriately selected.

  EXAMPLES Next, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to these.

A strip of a tough pitch copper foil (thickness 7.3 μm) of 99.9% or more copper bonded to a 12.5 μm thick PET film and a thermoplastic adhesive was used as a strip. This strip was electroplated in a continuous plating cell facing the tin anode. A phenolsulfonic acid bath was used as a plating bath, and 10 g / L of a surfactant (EN) and tin oxide were added to obtain a Sn concentration of 32 to 40 g / L. The plating conditions were a bath temperature of 45 to 55 ° C., a current density of 10 A / dm ² , and a plating thickness of 1.5 μm.
The obtained Sn plating film was obtained without using a brightener, and the size of the electrodeposited grains was 1.0 μm by JIS H0501 cutting method (2007 version).
In addition, the measuring method of the magnitude | size of an electrodeposition grain is as follows. A scanning electron microscope image at a magnification of 5000 times was taken from the surface of the Sn plating film. Using the grain boundary of this image as the electrodeposition grain boundary, count the number of electrodeposition grain boundaries at a total of 6 locations, 3 in the horizontal direction and 3 in the vertical direction, using the JIS H0501 cutting method (2007 version). The size of was calculated. In order to reduce measurement errors, the measurement locations were measured by averaging the size of the electrodeposited grains in a sample of about 10 × 10 mm.
The hardness of the Sn plating was 470 MPa. In addition, the hardness at the maximum load of 1 mN from the plated surface is measured, the measuring instrument is ENT-2100 made by Elionix, and Barcovich indenter (diamond triangular pyramid indenter) is used as the indenter. , Test mode: Load-unloading test (unloading after pushing to maximum load), measuring temperature: 32 ± 1 ° C. The hardness value was an average value of five measurements.
It was 0.005 mass% when the carbon content in Sn plating film was measured using the high frequency induction heating infrared absorption method.
In addition, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was not observed on the roll even when 4700 m was fed.
Further, as a corrosion resistance evaluation, a salt spray test (Z2371) (temperature: 35 ° C., salt water concentration: 5% (sodium chloride), spray pressure: 98 ± 10 kPa, spray time: 480 h) was performed, and good results were obtained.

Continuous plating was performed in exactly the same manner as in Example 1 except that the plating thickness was 0.5 μm.
The obtained Sn plating film was obtained without using a brightener, the size of the electrodeposited grains was 1.0 μm, and the hardness of the Sn plating was 480 MPa.
It was 0.007 mass% when the carbon content in Sn plating film was measured using the high frequency induction heating infrared absorption method.
In addition, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was not observed on the roll even when 4700 m was fed. Moreover, corrosion resistance evaluation was also a favorable result.

Continuous plating was performed in the same manner as in Example 1 except that the plating thickness was 1.9 μm and the current density was 7 A / dm ² .
The Sn plating film was obtained without using a brightener, the size of the electrodeposited grains was 2.0 μm, and the hardness of the Sn plating was 450 MPa.
It was 0.004 mass% when the carbon content in Sn plating film was measured using the high frequency induction heating infrared absorption method.
In addition, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was not observed on the roll even when 4700 m was fed. Moreover, corrosion resistance evaluation was also a favorable result.
The reason why the size of the electrodeposited grains is larger than the plating thickness is that the electrodeposited grains were observed from the plating surface, indicating that the electrodeposited grains are flat.

Continuous plating was performed in exactly the same manner as in Example 1 except that the plating thickness was 1.9 μm and the current density was 5 A / dm ² .
The obtained Sn plating film was obtained without using a brightener, the size of the electrodeposited grains was 2.5 μm, and the hardness of the Sn plating was 425 MPa.
It was 0.003 mass% when the carbon content in Sn plating film was measured using the high frequency induction heating infrared absorption method.
In addition, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was not observed on the roll even when 4700 m was fed. Moreover, corrosion resistance evaluation was also a favorable result.

A strip of a tough pitch copper foil (thickness 7.3 μm) of 99.9% or more copper bonded to a 12.5 μm thick PET film and a thermoplastic adhesive was used as a strip. This strip was electroplated in a continuous plating cell facing the tin anode. A phenolsulfonic acid bath was used as a plating bath, and 10 g / L of a surfactant (EN) and tin oxide were added to obtain a Sn concentration of 32 to 40 g / L. The plating conditions were such that the bath temperature was 55 to 65 ° C., the current density was 10 A / dm ² and the bath temperature was high, and the plating thickness was 1.9 μm.
The obtained Sn plating film was obtained without using a brightener, the size of the electrodeposited grains was 2.5 μm, and the hardness of the Sn plating was 475 MPa.
It was 0.01 mass% when the carbon content in Sn plating film was measured using the high frequency induction heating infrared absorption method.
In addition, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was not observed on the roll even when 4700 m was fed. Moreover, corrosion resistance evaluation was also a favorable result.

A strip was obtained by bonding a PET film having a thickness of 12.5 μm to one surface of a tough pitch copper foil (thickness: 7.3 μm) of 99.9% or more copper using a thermoplastic adhesive. This strip was electroplated in a continuous plating cell facing the tin anode. A phenol sulfonic acid bath was used as a plating bath, and a surfactant EN10 g / L, a brightener (paraaldehyde 5 ml / L, naphthaldehyde 0.1 ml / L) and tin oxide were added to obtain a Sn concentration of 32 to 40 g / L. . The plating conditions were a bath temperature of 45 to 55 ° C., a current density of 10 A / dm ² , and a plating thickness of 1.5 μm.
The size of the electrodeposited grains of the obtained Sn plating film was 1.0 μm, and the hardness was 495 MPa. It was 0.02 mass% when the amount of carbon in Sn plating film was measured using the high frequency induction heating infrared absorption method.
During continuous plating, when the roll on the plating outlet side was observed, Sn adhesion was observed on the roll when 4000 m foil was passed. Corrosion resistance was good.

Under the conditions of Example 1, after electroplating until 40000m was passed, the same evaluation as in Example 1 was performed (however, the presence or absence of Sn adhesion to the roll was not evaluated), but the corrosion resistance was good. Met.
In addition, about the sample of Examples 1-7, when the surface of the plating film was observed with a scanning electron microscope at a magnification of 1000 times, only a reflected electron image of Sn was observed uniformly, and a reflected electron image having a luminance different from that of Sn was observed. Not detected. From this, it is considered that the composition different from the Sn plating film does not exist on the surface of the plating film, and the copper foil as the base is not exposed.

Implemented except that a 12.5 μm thick PET film was bonded to one side of a 99.9% or more copper tough pitch copper foil (thickness 7.3 μm) using a urethane adhesive and the plating thickness was 0.4 μm. Continuous plating was performed exactly as in Example 1.
The obtained Sn plating was obtained without using a brightener, the size of the electrodeposited grains was 1.0 μm, and the hardness of the Sn plating was 495 MPa.
It was 0.005 mass% when the carbon content in Sn plating film was measured using the high frequency induction heating infrared absorption method.
Further, during the continuous plating, when the roll on the plating outlet side was observed, Sn adhesion was not observed even when the foil was fed through 4700 m, but corrosion was observed in the salt spray test (Z2371).

<Comparative Example 1>
Continuous plating was performed in exactly the same manner as in Example 1 except that the plating thickness was 1.0 μm and a brightener (paraaldehyde 12 ml / L, naphthaldehyde 0.2 ml / L) was added to the Sn plating bath.
The size of the electrodeposited grains of the obtained Sn plating film was 0.9 μm. The hardness of the Sn plating was 550 MPa.
It was 0.05 mass% when the carbon amount in Sn plating film was measured using the high frequency induction heating infrared absorption method.
Further, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was noticeably observed on the roll when 3000 m was passed through. The corrosion resistance evaluation was a good result.

<Comparative example 2>
Exactly the same as Example 1 except that the plating thickness was 1.5 μm and a brightener (paraaldehyde 12 ml / L, naphthaldehyde 0.2 ml / L) was added to the Sn plating bath to obtain a current density of 13 A / dm ^2. Then, continuous plating was performed.
The size of the electrodeposited grains of the obtained Sn plating film was 0.8 μm, and the hardness of the Sn plating was 580 MPa.
It was 0.10 mass% when the amount of carbon in Sn plating film was measured using the high frequency induction heating infrared absorption method.
Further, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was noticeably observed on the roll when 3000 m was passed through. The corrosion resistance evaluation was a good result.

<Comparative Example 3>
Exactly the same as Example 1 except that the plating thickness was 1.5 μm, and a brightener (paraaldehyde 12 ml / L, naphthaldehyde 0.2 ml / L) was added to the Sn plating bath to obtain a current density of 7 A / dm ^2. Then, continuous plating was performed.
The size of the electrodeposited grains of the obtained Sn plating film was 1.0 μm, and the hardness of the Sn plating was 505 MPa.
It was 0.10 mass% when the amount of carbon in Sn plating film was measured using the high frequency induction heating infrared absorption method.
Further, when the roll on the plating outlet side was observed during continuous plating, Sn adhesion was noticeably observed on the roll when 3500 m was passed through. The corrosion resistance evaluation was a good result.

<Comparative example 4>
Except that methanol (100 mg / L) was added to the Sn plating bath, the same evaluation as in Example 7 was performed after electroplating until 40000 m was passed in the same manner as in Example 7. However, the presence or absence of Sn adhesion to the roll was not evaluated.) However, corrosion was observed in the salt spray test (Z2371), and the corrosion resistance deteriorated.
Further, regarding the sample of Comparative Example 4, when the surface of the plating film was observed with a scanning electron microscope at a magnification of 1000 times, reflected electron images having brightness different from that of Sn were scattered in the reflected electron images of Sn. From this, it is considered that a composition different from that of the Sn plating film exists on the surface of the plating film, a defect of the plating film occurs, and the copper foil as the base is exposed.

  The obtained results are shown in Table 1.

As is clear from Table 1, in each of Examples 1 to 8 where the hardness of the Sn plating film was 500 MPa or less, Sn did not adhere to the roll for a long time (4000 m or more) even by continuous plating.
However, in Example 6 in which the amount of carbon in the Sn plating film exceeded 0.01% by mass, the plating time (4000 m) until Sn adhered to the roll was shorter than in other Examples 1 to 5. It was.
On the other hand, in the case of Comparative Examples 1 to 3 where the hardness of the Sn plating film exceeded 500 MPa, Sn adhered to the roll when continuous plating was performed for 3000 to 3500 m. In addition, Comparative Examples 1-3 had more brightener content than the Example.

  Further, in the case of Example 7 in which methanol was not contained in the plating bath, even if plating was performed for a longer period (40000 m), no defects were generated in the plating film, and the corrosion resistance was good. On the other hand, in the case of Comparative Example 4 containing 100 mg / L of methanol in the plating bath, when plating was performed for a long time (40000 m), defects were generated in the plating film, and the corrosion resistance was deteriorated.

It is the figure which showed an example of the composite material of this invention.

Explanation of symbols

1 Copper foil (or copper alloy foil)
2 Sn plating film 4 Resin layer (or film)

Claims (9)

  The other surface of the copper foil or copper alloy foil laminated with a resin layer or film is formed from a Sn or Sn alloy electroplating bath not containing methanol, and is a Sn or Sn alloy plating film having a hardness of 500 MPa or less, When the surface of the Sn or Sn alloy plating film is observed with a scanning electron microscope (however, when the thickness of the Sn or Sn alloy plating film exceeds 1.5 μm, the thickness of the Sn or Sn alloy plating film is 1.5 μm). Sn or Sn alloy plating film in which the copper foil or copper alloy foil is not exposed.   The Sn or Sn alloy plating film according to claim 1, wherein the amount of carbon in the Sn or Sn alloy plating film is 0.01% by mass or less.   The Sn or Sn alloy plating film according to claim 1 or 2, wherein the Sn or Sn alloy plating film has a thickness of 0.5 µm or more.   The Sn or Sn alloy plating film according to claim 1, wherein the Sn or Sn alloy plating film has a thickness of less than 2.0 μm.   The Sn or Sn alloy plating film according to any one of claims 1 to 4, wherein the Sn or Sn alloy plating film is formed by continuous plating.   The copper foil or copper alloy foil, the resin layer or film laminated on one surface of the copper foil or copper alloy foil, and the other surface of the copper foil or copper alloy foil. A composite material comprising the Sn or Sn alloy plating film according to any one of the above.   The composite material according to claim 6, wherein the thickness is 0.1 mm or less.   The composite material according to claim 7, which is used for an electromagnetic wave shield.   After laminating the resin layer or film on one surface of the copper foil or copper alloy foil, the other surface of the copper foil or copper alloy foil is made of Sn or Sn alloy electroplating bath that does not contain methanol. The manufacturing method of the composite material which forms Sn or Sn alloy plating film which is 500 Mpa or less.

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