JP2009287095A - PLATED FILM OF Sn, AND COMPOSITE MATERIAL HAVING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plated film of Sn, which is superior in the maintenability of a roll and can enhance the productivity by preventing the rubbing or falling of the plated film of Sn, and to provide a composite material having the same. <P>SOLUTION: The plated film 2 of Sn is formed on the other side of a copper foil or copper alloy foil 1 which is stacked on a resin layer or a film 4, and the sizes of electrodeposited particles in the film are 1.0 μm or larger. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

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.

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 (uniform color, no color spots and patterns) and 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 1).

Japanese Patent No. 3007207

  However, when Sn plating with small electrodeposition grains (for example, normal bright Sn plating) is performed on a metal foil such as copper or copper alloy foil in a continuous line, the Sn plating surface is rubbed and transferred and adhered to the roll. There is a problem. If plating adheres to the roll surface, the productivity during plating is reduced by cleaning the roll, etc., and if the adhesion is extremely severe, the Sn plating film becomes thin, which may lead to a decrease in the corrosion resistance of the resulting composite material. This is a problem that cannot be ignored.

  The reason why such a defect occurs is unknown, but it is considered that when the electrodeposited grains of Sn plating are small, the contact area between the roll and the electrodeposited grains is increased. That is, since copper foil is thin, its strength is low, and it is easy to bend and wrinkle when passing through a continuous line such as Sn plating. Therefore, when using as a shielding material, it is common to perform Sn plating by pasting resin or a film on copper foil first. However, even a copper foil with such a resin or film attached thereto is likely to bend or wrinkle when the tension applied to the strip during continuous plating is increased. Therefore, in order to stably prevent the occurrence of folds and wrinkles, it is necessary to pass the foil with a low tension. On the other hand, when the tension applied to the strip is lowered, the contact pressure between the roll and the strip is reduced. , Slip easily between roll and strip. In particular, when the contact area between the roll and the electrodeposited grains is large, the contact pressure increases because the contact surface is increased, and slipping easily occurs. When the roll and the Sn plating film slip, the Sn plating surface This is considered to be because the degree of rubbing increases and the electrodeposited grains fall and transfer and adhere to the roll.

Moreover, when using the composite material obtained by Sn-plating copper foil for electromagnetic wave shielding materials, such as a cable, a composite material is wound around a cable outer periphery, and also the resin is coat | covered on the outer side. In this resin coating process, if a composite material with an electrodeposited grain of Sn plating of 0.9 μm or less is used, the contact area between the die and the electrodeposited grain is increased for the same reason as described above, and the composite material becomes a die (die). When passing through, the Sn plating film tends to fall off, and the possibility that Sn residue adheres to the die increases. And if Sn residue adheres to the die, time is required for maintenance, and productivity is lowered.
The present invention has been made to solve the above-described problems, and has an Sn plating film capable of improving the productivity by preventing the Sn plating film from sliding or falling off during plating or use. The purpose is to provide composite materials.

  As a result of various studies, the present inventors have succeeded in reducing the sliding or dropping of the Sn plating film by increasing the electrodeposited grains of the Sn plating film on the surface of the copper or copper alloy foil.

  In order to achieve the above object, the Sn plating film of the present invention is formed on the other surface of the copper foil or copper alloy foil laminated with a resin layer or film, and the size of the electrodeposited grains is 1.0 μm or more. is there.

  The thickness of the Sn plating film is preferably 0.5 μm or more.

  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 plating film.

  The thickness of the composite material is preferably 0.1 mm or less.

  The electrodeposited grains in the present invention are defined as follows. As shown in FIG. 2, the Sn plating film grows in a semicircular shape centering on the Sn plating crystal nucleus, and the same nucleus is laminated on the grown grain. When viewed from the surface of the Sn plating film, 3 and 4 are observed in the form of particles. The individual particles are defined as electrodeposited grains. Specifically, it is obtained based on the JIS H0501 cutting method (2007 version), with the electrode boundary as the grain boundary observed when a scanning electron microscope image at a magnification of 5000 times is taken from the Sn plating film surface. Let the obtained particle size be the size of the electrodeposited particles.

  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.
Although the thickness in particular of copper foil (or copper alloy foil) is not restrict | limited, For example, the thing of 5-50 micrometers can be used conveniently.
In addition, as copper foil (or copper alloy foil), it is preferable to use a rolled foil having higher strength than electrolytic foil.
Moreover, the surface roughness of the copper foil (or copper alloy foil) can be 0.3 μm or less, preferably 0.2 μm or less in terms of the center line average roughness, but if the surface roughness is less than 0.1 μm Adhesiveness with the resin layer may be insufficient.

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.

The size of the electrodeposited grains of the Sn plating film is 1.0 μm or more. If the size of the electrodeposited grains of the Sn plating film is 1.0 μm or more, the roll and the electrodeposited grains are in point contact at the time of Sn plating, so that the contact area between the two becomes small and the contact pressure with the roll becomes strong. For this reason, slip on the roll is reduced, and transfer and adhesion to the roll due to the drop of the electrodeposited grains are eliminated. Moreover, also when using the obtained composite material for electromagnetic wave shielding materials, such as a cable, the contact area of Sn plating film and a roll becomes small at the time of a process. For this reason, Sn adhesion to a roll can be prevented and productivity can be improved. And when the obtained composite material is processed, the Sn plating film does not fall off and adhesion does not deteriorate.
The upper limit of the size of the electrodeposited grains of the Sn plating film is not particularly limited because it varies depending on the manufacturing conditions of the Sn plating. However, if the size of the electrodeposited grains exceeds 3 μm, the plating efficiency may be reduced or uneven. The appearance may be different. Therefore, the size of the electrodeposited grains of the Sn plating film is preferably 1.0 to 3.0 μm.
The thickness of the Sn 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.
In addition, the upper limit of the thickness of the Sn plating film is not particularly limited because it varies depending on the manufacturing conditions of Sn plating, etc. However, even if the Sn plating is thickened exceeding 2 μm, no further improvement in corrosion resistance and solderability is observed. On the contrary, there are also negative aspects such as increasing the Sn plating allowance and decreasing the productivity. Therefore, it is preferable that the thickness of the Sn plating film is 0.5 to 2 μm.

The method for measuring the size of the electrodeposited grains of the Sn plating film is performed as follows. First, a scanning electron microscope image at a magnification of 5000 times is taken from the Sn plating film surface. With respect to this image, the size of the electrodeposited grains is determined by counting the number of electrodeposited grain boundaries at a total of six places, three in the horizontal direction and three in the vertical direction, by the JIS H0501 cutting method (2007 version).
In order to reduce measurement errors, it is preferable to measure and average the size of the electrodeposited grains within a visual field of about 10 × 10 mm.
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.

  Examples of a method for setting the size of the electrodeposited grains of the Sn plating film to 1.0 μm or more include, for example, a method of adjusting current density, Sn concentration and bath temperature, respectively; a brightener (for example, formalin and aldehyde) in the Sn plating bath The method of carrying out granular electroplating without adding chemicals (commercially available chemicals such as imidazole, benzal acetone). However, a naphthol surfactant such as EN (ethoxylated naphthol) may be added to the Sn plating bath. Further, nonionic surfactants such as ENSA (ethoxylated naphthol sulfonic acid), polyethylene glycol, and polyethylene glycol nonylphenol ether may be added to the Sn plating bath. In addition to the surfactant, an organic substance such as naphthol having a low gloss effect may be added.

Examples of the base for the Sn plating bath include phenolsulfonic acid, sulfuric acid, methanesulfonic acid and the like.
The plating conditions can be adjusted to increase the electrodeposited grains by reducing the current density, increasing the Sn concentration in the bath, and increasing the bath temperature. 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 granular electrodeposited Sn can be uniformly electrodeposited on the copper foil surface. Since it differs, it is not specifically limited.

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

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 (EN) 10 g / 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 8 to 11 A / dm ² , and a plating thickness of 1.5 μm.
It was 1.0 micrometer when the magnitude | size of the electrodeposition particle | grains of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version). (See Figure 3)
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.
It was 1.0 micrometer when the magnitude | size of the electrodeposition particle | grains of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version).
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 exactly the same manner as in Example 1 except that the plating thickness was 2.0 μm and the current density was 6 to 8 A / dm ² .
It was 2.0 micrometers when the magnitude | size of the electrodeposited grain of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version).
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 2.0 μm and the current density was 5 to 6 A / dm ² .
When the size of the electrodeposited grains of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version), it was 2.5 μm.
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 exactly the same manner as in Example 1 except that the plating thickness was 0.4 μm.
It was 1.0 micrometer when the magnitude | size of the electrodeposition particle | grains of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version).
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).
From this, it can be seen that it is more preferable that the plating thickness is 0.5 μm or more.

<Comparative Example 1>
Continuous plating was performed in the same manner as in Example 1 except that the plating thickness was 1.0 μm and the brightener paraaldehyde 12 ml / L, naphthaldehyde 0.2 ml / L) was added to the Sn plating bath.
When the size of the electrodeposited grains of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version), it was 0.9 μm (see FIG. 4).
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>
Continuous plating was performed in exactly the same manner as in Example 1 except that the plating thickness was 0.5 μm and the current density was 12 to 15 A / dm ² .
When the size of the electrodeposited grains of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version), it was 0.9 μm.
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>
Except that the plating thickness was 1.5 μm, brightener paraaldehyde 12 ml / L, naphthaldehyde 0.2 ml / L) was added to the Sn plating bath, and the current density was 12 to 15 A / dm ^2. Similarly, continuous plating was performed.
It was 0.8 micrometer when the magnitude | size of the electrodeposited grain of the obtained Sn plating film was measured by the JIS H0501 cutting method (2007 version).
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.

  The obtained results are shown in Table 1.

As is clear from Table 1, in each Example in which the size of the electrodeposited grains of the Sn plating film was 1.0 μm or more, Sn did not adhere to the roll for a long time even by continuous plating.
On the other hand, in the case of Comparative Examples 1 to 4 in which the size of the electrodeposited grains of the Sn plating film was less than 1.0 μm, Sn adhered to the roll when continuous plating was performed 3000 m.

It is the figure which showed an example of the composite material of this invention. It is a schematic diagram which shows the Sn plating electrodeposition grain formed in copper foil (or copper alloy foil). It is a scanning electron microscope image of the magnification of 5000 times from the Sn plating film surface of the example 1 of an invention. 3 is a scanning electron microscope image at a magnification of 5000 times from the Sn plating film surface of Comparative Example 1. FIG.

Explanation of symbols

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

Claims (4)

  An Sn plating film formed on the other surface of a copper foil or copper alloy foil on which a resin layer or a film is laminated and having a size of electrodeposited grains of 1.0 μm or more.   The Sn plating film according to claim 1, wherein the thickness is 0.5 μm or more.   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 formed on the other surface of the copper foil or copper alloy foil. A composite material comprising the described Sn plating film.   The composite material according to claim 3, wherein the thickness is 0.1 mm or less.