JP6703452B2 - Electroplating method - Google Patents

Description

The present invention relates to an electroplating method, and in particular, an electroplating method in which a plating material is plated by passing an electric current between an anode in an anode bag and a plating material outside the anode bag in a plating solution in a plating tank. Regarding

Conventionally, in the method of electroplating a material to be plated by passing an electric current between a soluble anode in the plating solution in the plating tank and the material to be plated, it occurs when the anode dissolves in the plating solution during electroplating. In order to prevent the sludge (or slime) from being deposited on the material to be plated, the anode is housed in the anode bag, and the material to be plated is arranged outside the anode bag.

However, when electroplating is continuously performed for a long time, sludge is settled in the anode bag and the anode bag is clogged. Therefore, the deteriorated plating solution generated by the electric reaction of the anode cannot be exchanged inside and outside the anode bag, the conductivity of the plating solution at the bottom of the anode bag decreases, and the current from near the lower end of the anode decreases. , The thickness of the plating film on the lower side of the material to be plated decreases.

In order to solve such a problem, as a method for removing sludge (or slime) in the anode bag in the plating tank, a slime suction port is provided at the bottom of the anode bag surrounding the anode in the plating tank to form a plating solution. And a method of sucking out slime (for example, refer to Patent Document 1), or a method of installing a suction portion for sucking sludge scattered and settled from the anode case on at least one of the left side and the right side of the anode case and outside or inside the bottom (for example, , Patent Document 2) and the like have been proposed.

JP-A-7-286299 (paragraph number 0004-0006) Japanese Patent No. 4445354 (paragraph number 0008)

However, in the methods of Patent Documents 1 and 2, the sludge accumulated on the bottom of the anode bag is sucked together with the plating solution, and the plating solution from which the sludge has been removed by the filter is returned to the inside of the anode bag. The sludge will be sucked in and the filter life will be shortened. In addition, a large pipe must be installed at the bottom of the anode bag to suck and remove the sludge, which requires a large space in the plating tank.

Therefore, in view of such a conventional problem, the present invention, in the plating solution in the plating tank, applies a current between the anode in the anode bag and the material to be plated outside the anode bag to plate the material to be plated. In the electroplating method, even if the sludge accumulated on the bottom of the anode bag is not removed, the decrease in the conductivity of the plating solution in the anode bag is suppressed, and the thickness of the plating film formed on the material to be plated is suppressed. It is an object of the present invention to provide an electroplating method capable of suppressing the change in

As a result of intensive research to solve the above problems, the inventors of the present invention performed a long strip-shaped plate-shaped material along its longitudinal direction in a plating tank so that its width direction is substantially vertical. In the electroplating method, in which the material to be plated is plated by applying a current between the anode in the anode bag and the material to be plated outside the anode bag in the plating solution in the plating tank while transporting, When a suction pipe is introduced and the suction port is arranged such that the height of the lowermost end of the suction port of the suction pipe is 70 mm or less in the vertical direction from the lowermost end of the anode, the material to be plated is plated. In addition, after sucking a part of the plating solution from the suction port while maintaining the maximum amount of decrease in the height of the surface of the plating solution to 1 to 60 mm, by stopping sucking the plating solution alternately, By intermittently sucking part of the plating solution and discharging it from the plating tank, it is possible to suppress the decrease in the conductivity of the plating solution in the anode bag without removing the sludge accumulated on the bottom of the anode bag. The inventors have found that it is possible to suppress changes in the thickness of the plating film formed on the material to be plated, and have completed the present invention.

That is, the electroplating method according to the present invention, the long strip plate-shaped material to be plated in the plating tank while being conveyed along the longitudinal direction in the plating tank such that the width direction thereof is substantially vertical. In the electroplating method, in which a current is passed between the anode in the anode bag and the material to be plated outside the anode bag in the plating solution to plate the material to be plated, a suction pipe is introduced into the anode bag and the suction is performed. The suction port is arranged so that the height of the bottom end of the suction port of the tube is 70 mm or less in the vertical direction from the bottom end of the anode, and when plating the material to be plated, the level of the plating solution While sucking a part of the plating solution from the suction port while maintaining the maximum height reduction of 1 to 60 mm, the suction of the plating solution is alternately stopped to intermittently part of the plating solution. It is characterized in that it is sucked into and discharged from the plating tank.

In this electroplating method, the anode is preferably a plurality of anode balls housed in an anode case in an anode bag. Alternatively, a plurality of anodes are housed in each of two anode cases that are arranged in the anode bag in a direction substantially perpendicular to the vertical direction and substantially parallel to the surface facing the material to be plated and separated from each other. It may be an anode ball. In this case, the suction port of the suction tube is preferably arranged between the side surfaces of the two anode cases. Further, it is preferable that the suction time of each of the plating solutions when intermittently sucking a part of the plating solution is shorter than the time of stopping each suction of the plating solution. In this case, it is preferable that the suction time of each plating solution is 10 to 250 seconds and the suction time of each plating solution is 300 to 2000 seconds. Further, it is preferable that the anode is arranged so as to face at least one surface of the material to be plated. Further, it is preferable that the suction port of the suction tube is arranged at a substantially central portion of the anode bag in a direction substantially perpendicular to the vertical direction and in a direction substantially parallel to the surface facing the material to be plated.

According to the present invention, in an electroplating method for plating a material to be plated by passing a current between an anode in an anode bag and a material to be plated outside the anode bag in a plating solution in a plating tank, Even if the sludge accumulated on the bottom is not removed, it is possible to suppress the decrease in the conductivity of the plating solution in the anode bag and suppress the change in the thickness of the plating film formed on the material to be plated.

It is a figure which shows schematically the positional relationship of the anode and cathode in the plating tank of the electroplating apparatus used for embodiment of the electroplating method by this invention. It is a figure which shows schematically the anode of the electroplating apparatus of FIG. 1 is a plan view schematically showing the anode and the suction tube of the electroplating apparatus. It is a side view which shows schematically the anode and suction tube of the electroplating apparatus of FIG. It is a perspective view which shows schematically the positional relationship between the anode case and the suction tube of the electroplating apparatus of FIG.

Hereinafter, embodiments of the electroplating method according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 to 4, in the embodiment of the electroplating method according to the present invention, a plurality of (four in the illustrated embodiment) anode bags 14 are immersed in the plating solution 12 in the plating tank 10. , One or a plurality (two in the illustrated embodiment) of anode cases 16 are housed in each of the anode bags 14, and a plurality of soluble anode balls 18 are housed in each of the anode cases 16. A suction pipe 22 is introduced into the anode bag 14, and one or a plurality (three in the illustrated embodiment) of the suction pipe 22 are provided with suction ports 22 a (side faces of the anode case 16 (where the anode balls 18 are accommodated)). Preferably, the anode is disposed in the vicinity of the lower end portion of the side surface that does not face the material to be plated 20), the anode in the anode bag 14 (the plurality of anode balls 18 housed in each anode case 16), and the plating tank. When the material to be plated 20 is plated by passing a current between it and the material to be plated 20 as the cathode that is introduced into (outside of the anode bag 14) the plating solution 12 inside the anode bag 12 in the plating tank 10. Suction of the plating solution 12 after sucking a part of the plating solution 12 from the suction port 22a while maintaining the maximum reduction amount of the height of the liquid surface of the plating solution 12 within 1 to 60 mm (preferably 5 to 55 mm). By alternately repeating the above step, a part of the plating solution 12 is intermittently sucked and discharged from the plating tank 10.

The material 20 to be plated is a long strip-shaped rolled plate made of copper or a copper alloy, and is arranged in the plating tank 10 along the longitudinal direction of the plating tank 10 so that the width direction thereof is substantially vertical. It is supposed to be transported in.

The anode bag 14 and the anode case 16 are suspended from a copper anode bar 26 that extends substantially horizontally above the plating tank 10 via a titanium plate material 24, and from both surfaces of the material 20 to be plated in the plating tank 10. They are arranged at a predetermined interval so as to face at least one surface (both surfaces in the illustrated embodiment) (substantially parallel to the material to be plated 20).

The anode bag 14 is made of a material that allows the plating solution 12 to pass through but does not allow the sludge 28 (generated and settled during electroplating) to pass through. For example, polypropylene, polyester, polyethylene, Saran (registered trademark), Teflon ( (Registered trademark) and the like.

As shown in FIG. 4, the anode case 16 has a titanium basket (upper surface is open) that defines a substantially rectangular parallelepiped space (having a length of about 100 to 2000 mm, a width of about 20 to 100 mm, and a height of about 100 to 600 mm). However, the side surface is a mesh and the bottom surface is a plate-shaped casing), and accommodates a plurality of anode balls 18 therein and allows the plating solution and the sludge 28 to pass therethrough. The anode ball 18 is a substantially spherical body made of the same metal as the plating film formed on the plated material 20, for example, Sn in the case of Sn plating and Ni in the case of Ni plating. The bottom surface of the anode case 16 is formed with a drain hole having a size that does not allow the anode ball 18 reduced in size by electroplating to pass through but allows the plating solution to pass through.

At a substantially central portion of the anode bag 14 in a direction substantially perpendicular to the vertical direction and substantially parallel to a surface facing the material to be plated 20 so as to face the side surface of the anode case 16 (in the illustrated embodiment, the anode The suction port 22a (one or more) of the suction tube 22 is arranged between the opposing side surfaces of the two anode cases 16 housed in the bag 14, and the height of the lowermost end of the suction port 22a is the anode case. The anode balls 18 in 16 are arranged so as to have a height of 70 mm or less (preferably 60 mm or less) vertically upward from the lowermost end. The height of the uppermost end of the suction port 22a is preferably 70 mm or less in the vertical direction from the lowermost end of the anode ball 18 in the anode case 16.

The side surface of the anode case 16 is spaced from the side surface of the facing anode bag 14 at a predetermined distance (preferably a distance of 5 to 10 mm), and the bottom surface of the anode case 16 is at a predetermined distance from the bottom surface of the anode bag 14 (preferably, a distance). The distance is 30 mm or more, and more preferably about 50 mm. Since the bottom surface of the anode case 16 is separated from the bottom surface of the anode bag 14 at a predetermined interval in this manner, the suction port 22a of the suction tube 22 can be prevented from being blocked by the anode bag 16. Even if the sludge 28 is deposited on the bottom surface of the anode bag 14, a gap is formed between the sludge 28 and the anode case 14, and suction of the sludge 28 can be suppressed. The suction of the plating solution 12 from the suction port 22a of the suction tube 22 is performed intermittently so that the suction of the plating solution 12 and the stop of the suction are alternately repeated for a fixed time, and the suction time of the plating solution 12 (preferably 10 times). ~250 seconds) is shorter than the suction stop time of the plating solution 12 (preferably 300 to 2000 seconds). The plating solution 12 (in the anode bag 14) sucked by the suction tube 22 is adjusted in composition in a plating solution adjusting tank through a filter (not shown) and returned to the inside of the plating tank 10 (outside of the anode bag 14). During the suction stop time of the plating solution 12, the plating solution 12 permeates into the anode bag 14 and the height of the liquid surface of the plating solution 12 in the anode bag 14 returns to the initial height.

In the embodiment of the electroplating method according to the present invention, the height of the lowermost end of the suction port 22a of the suction pipe 22 introduced into the anode bag 14 in the plating solution 12 in the plating tank 10 is the anode (in the anode case 16). The suction port 22a of the suction pipe 22 is formed so as to have a height of 70 mm or less (preferably 60 mm or less) vertically upward from the lowermost end of the accommodated anode ball 18) and the side surfaces of two adjacent anodes of the plurality of anodes. And the suction port while maintaining the maximum amount of decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 in the plating tank 10 at 1 to 60 mm when the material 20 to be plated is plated. Since a part of the plating solution 12 is sucked from 22a and discharged from the plating tank 10, suction of the sludge 28 accumulated on the bottom of the anode bag 14 is suppressed, and the plating solution 12 near the lower end of the anode is effective. Since it can be sucked into the anode bag 14, the plating solution 12 outside the anode bag 14 can be supplied into the anode bag 14, and the deteriorated plating solution 12 generated by the electric reaction of the anode can be replaced inside and outside the anode bag 14. The lowering of the conductivity of the plating solution 12 at the bottom of the bag 14 is suppressed (the difference in the conductivity of the plating solution 12 in the anode bag 14 in the depth direction is reduced), and the decrease of the current from the vicinity of the lower end of the anode is suppressed. , It is possible to suppress a decrease in the thickness of the plating film on the lower side of the material to be plated 20 and to suppress a change in the thickness of the plating film in the vertical direction of the plating tank 10, and to remove sludge by suction. It is not necessary to install a large pipe for doing so at the bottom of the anode bag, and it is possible to prevent suction of a large amount of sludge and prevent the life of the filter from being shortened.

The embodiment of the electroplating method according to the present invention is preferably applied to Sn plating in which a large amount of sludge is generated.

Hereinafter, examples of the electroplating method according to the present invention will be described in detail.

[Example 1]
In the electroplating apparatus shown in FIGS. 1 to 4, stannous sulfate (SnSO ₄ ) 70 g/L, sulfuric acid (H ₂ SO ₄ ) 75 g/L, cresolsulfonic acid 30 g/L (as a leveling agent) (surfactant) As a Sn plating solution consisting of an aqueous solution containing 2 mL/L of polyoxyethylene alkylamine is placed in a plating tank 10 having a capacity of about 300 L, and the length of the anode case 16 in the longitudinal direction is 500 mm, the width is 60 mm, and the height is 60 mm. Is 400 mm, the distance between the bottom surface of the anode case 16 and the bottom surface of the anode bag 14 is about 50 mm, Sn balls having a diameter of 50 mm are used as the anode balls 18, and a width of 250 mm and a thickness of 0. While carrying a 25 mm long strip-shaped Cu-made rolled plate as the material 20 to be plated, electroplating was performed to form a Sn plating film having a thickness of 1.0 μm on both surfaces of the material 20 to be plated.

It should be noted that the three suction ports 22a of the suction pipe 22 are arranged between the opposing side surfaces of the two anode cases 16 in each anode bag 14 (the central portion in the longitudinal direction within the anode bag 14), and the suction ports 22a are set to the maximum positions. The lower end (the suction port 22a at the tip of the suction pipe 22) is arranged at the lowest end of the anode ball 18 in the anode case 16 (the height of 0 mm upward in the vertical direction), and the upper end of the suction port 22a (the suction pipe 22). The uppermost end of the suction port 22a on the side surface near the tip end of the suction tube 22 in the vertical direction upward from the lowermost end of the anode ball 18 in the anode case 16 (the suction port 22a having a diameter of 10 mm is attached to the tip of the suction tube 22). 10 mm above the vertical direction), and during the electroplating, the suction time of the plating solution 12 is 120 seconds, the suction stop time is 840 seconds, and the plating solution 12 is intermittently sucked at a flow rate of 5 L/min. Sucked into. The maximum decrease in the height of the liquid surface of the plating solution 12 in the anode bag 14 during the suction was 20 mm. It should be noted that the plating solution 12 outside the anode bag 14 permeated into the anode bag 14 within the suction stop time after this suction, and the height of the liquid surface of the plating solution 12 in the anode bag 14 returned to the initial height. ..

Electroplating is carried out in this manner, and after 2 weeks, the supernatant (about 100 mL) outside the anode bag 14 is sampled to measure the electrical conductivity, and at the same time, the introduction side and the center of the material 20 to be plated inside the anode bag 14 are measured. Of the plating solution 12 (about 100 mL) at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surface on the discharge side and the discharge side, the conductivity of the plating solution 12 outside the anode bag 14 was measured. The conductivity of the supernatant liquid is 211 mS/cm, and the conductivity of the plating liquid 12 at a position 300 mm vertically below the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The reductions (with respect to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) were 28 mS/cm, 30 mS/cm and 38 mS/cm, respectively. The electric conductivity was measured by using an electric conductivity meter (Seven2Go manufactured by METTLER TOLEDO Co., Ltd.), setting a sensor in the sample, and measuring the time by tens of seconds by an electromagnetic induction method.

In addition, the thickness of each Sn plating film (portion excluding the peripheral portion of 10 mm from the widthwise end portion thereof) on both surfaces of the material to be plated 20 was measured at positions at intervals of 5 mm in the width direction, and the Sn plating film The difference between the maximum value and the minimum value in the width direction (the larger value between the maximum value and the minimum value in the width direction of the Sn plating film on each surface, whichever is larger) was calculated and found to be 0.2 μm. Yes, the difference in thickness was small. The thickness of the Sn plating film was measured by a fluorescent X-ray film thickness meter (SFT3300S manufactured by SSI Nanoscience Co., Ltd.) in a range of 0.5 mm in diameter for 15 seconds by an excitation method.

[Example 2]
At the time of electroplating, the same method as in Example 1 except that the suction time of the plating solution 12 was set to 60 seconds, the suction stop time was set to 420 seconds, and the suction flow rate of the plating solution 12 was set to 4 L/min to intermittently suction. Electroplating was performed to form Sn-plated films with a thickness of 1.0 μm on both surfaces of the material 20 to be plated. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during the suction of the plating solution 12 was 20 mm. It should be noted that the plating solution 12 outside the anode bag 14 permeated into the anode bag 14 within the suction stop time after this suction, and the height of the liquid surface of the plating solution 12 in the anode bag 14 returned to the initial height. ..

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The conductivity of the supernatant liquid is 220 mS/cm, and the conductivity of the plating liquid 12 at a position 300 mm vertically below the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 35 mS/cm, 30 mS/cm and 28 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.2 μm, and the difference in thickness was small.

[Example 3]
At the time of electroplating, electroplating was performed in the same manner as in Example 1 except that the suction flow rate of the plating solution 12 was set to 2 L/min and suction was performed intermittently to obtain a thickness of 1. A Sn plating film of 0 μm was formed. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during suction of the plating solution 12 was 10 mm. It should be noted that the plating solution 12 outside the anode bag 14 permeated into the anode bag 14 within the suction stop time after this suction, and the height of the liquid surface of the plating solution 12 in the anode bag 14 returned to the initial height. ..

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The electric conductivity of the supernatant liquid is 216 mS/cm, and the electric conductivity of the plating liquid 12 at a position 300 mm vertically downward from the liquid surface on the introduction side, the central portion and the discharge side of the material to be plated in the anode bag 14 ( The reductions (with respect to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) were 82 mS/cm, 40 mS/cm and 77 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.3 μm, and the difference in thickness was small.

[Example 4]
At the time of electroplating, electroplating was performed by the same method as in Example 1 except that the suction flow rate of the plating solution 12 was set to 10 L/min to intermittently suck the plated material 20 to a thickness of 1. A Sn plating film of 0 μm was formed. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during suction of the plating solution 12 was 50 mm. It should be noted that the plating solution 12 outside the anode bag 14 permeated into the anode bag 14 within the suction stop time after this suction, and the height of the liquid surface of the plating solution 12 in the anode bag 14 returned to the initial height. ..

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The conductivity of the supernatant liquid is 217 mS/cm, and the conductivity of the plating liquid 12 at a position 300 mm vertically downward from the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 19 mS/cm, 10 mS/cm and 22 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.2 μm, and the difference in thickness was small.

[Example 5]
The lowermost end of the suction port 22a of the suction pipe 22 is arranged vertically upward from the lowermost end of the anode ball 18 in the anode case 16 at a height of 50 mm (the uppermost end of the suction port 22a is located in the anode case 18). Electroplating is performed in the same manner as in Example 1 except that the Sn plating film having a thickness of 1.0 μm is formed on both surfaces of the material to be plated 20 except that the Sn plating film is arranged at a height of 70 mm vertically above the bottom end. did. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during the suction of the plating solution 12 was 20 mm. It should be noted that the plating solution 12 outside the anode bag 14 permeated into the anode bag 14 within the suction stop time after this suction, and the height of the liquid surface of the plating solution 12 in the anode bag 14 returned to the initial height. ..

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The electric conductivity of the supernatant liquid is 230 mS/cm, and the electric conductivity of the plating liquid 12 at a position 300 mm vertically below the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 73 mS/cm, 43 mS/cm, and 65 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.3 μm, and the difference in thickness was small.

[Example 6]
The lowermost end of the suction port 22a of the suction tube 22 is arranged vertically upward from the lowermost end of the anode ball 18 in the anode case 16 at a height of 20 mm (the uppermost end of the suction port 22a is located in the anode case 18). Example 1 except that the suction was performed intermittently with the suction time of the plating solution 12 set to 45 seconds and the suction stop time set to 315 seconds during electroplating. Electroplating was performed in the same manner as in (1) to form a Sn plating film having a thickness of 1.0 μm on both surfaces of the material to be plated 20. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during suction of the plating solution 12 was 10 mm. It should be noted that the plating solution 12 outside the anode bag 14 permeated into the anode bag 14 within the suction stop time after this suction, and the height of the liquid surface of the plating solution 12 in the anode bag 14 returned to the initial height. ..

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The conductivity of the supernatant liquid is 224 mS/cm, and the conductivity of the plating liquid 12 at a position 300 mm vertically downward from the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 40 mS/cm, 37 mS/cm and 40 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.3 μm, and the difference in thickness was small.

[Comparative Example 1]
Electroplating was performed in the same manner as in Example 1 except that the plating solution 12 was not sucked to form Sn-plated films with a thickness of 1.0 μm on both surfaces of the plated material 20.

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The conductivity of the supernatant liquid is 217 mS/cm, and the conductivity of the plating liquid 12 at a position 300 mm vertically downward from the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The reductions (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) were 133 mS/cm, 135 mS/cm and 128 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.7 μm, and the difference in thickness was large.

[Comparative example 2]
At the time of electroplating, electroplating was performed in the same manner as in Example 1 except that the suction flow rate of the plating solution 12 was set to 0.5 L/min and suction was performed intermittently to obtain a thickness on both surfaces of the material 20 to be plated. A 1.0 μm Sn plating film was formed. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during the suction of the plating solution 12 was 0 mm.

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The conductivity of the supernatant liquid is 220 mS/cm, and the conductivity of the plating liquid 12 at a position 300 mm vertically below the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 128 mS/cm, 115 mS/cm and 122 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the width of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.6 μm, and the difference in thickness was large.

[Comparative Example 3]
At the time of electroplating, electroplating was performed in the same manner as in Example 1 except that the suction flow rate of the plating solution 12 was intermittently set to 15 L/min, and the thickness of 1. A Sn plating film of 0 μm was formed. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during suction of the plating solution 12 was as large as 70 mm.

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The electric conductivity of the supernatant liquid is 219 mS/cm, and the electric conductivity of the plating liquid 12 at a position 300 mm vertically below the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 13 mS/cm, 12 mS/cm and 15 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the width of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.6 μm, and the difference in thickness was large. In this comparative example, since the maximum amount of decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during suction of the plating solution 12 was as large as 80 mm, the current flowing to the upper side of the material to be plated 20 was small. Therefore, it is considered that the Sn plating film on the upper side of the material 20 to be plated becomes thin and the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction becomes large.

[Comparative Example 4]
The lowermost end of the suction port 22a of the suction pipe 22 is arranged vertically upward from the lowermost end of the anode ball 18 in the anode case 16 by 100 mm (the uppermost end of the suction port 22a is located in the anode case 18 in the anode case 16). Electrolyzed by the same method as in Example 1 except that it was arranged vertically upward from the bottom end at a height of 120 mm) and intermittently sucked at a suction flow rate of the plating solution 12 of 10 L/min during electroplating. Plating was performed to form a Sn plating film having a thickness of 1.0 μm on both surfaces of the material to be plated 20. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during suction of the plating solution 12 was 50 mm. It should be noted that the plating solution 12 outside the anode bag 14 permeated into the anode bag 14 within the suction stop time after this suction, and the height of the liquid surface of the plating solution 12 in the anode bag 14 returned to the initial height. ..

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The electric conductivity of the supernatant liquid is 226 mS/cm, and the electric conductivity of the plating liquid 12 at a position 300 mm vertically below the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central portion and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 121 mS/cm, 60 mS/cm and 108 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the width of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.6 μm, and the difference in thickness was large.

[Comparative Example 5]
At the time of electroplating, electroplating was performed in the same manner as in Example 1 except that the suction flow rate of the plating solution 12 was continuously set to 10 L/min, and Sn plating films were formed on both surfaces of the plated material 20. Formed. The electroplating was stopped because the maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 became too large by 100 mm due to the suction of the plating solution 12. The conductivity of the supernatant of the plating solution 12 outside the anode bag 14 was measured by the same method as in Example 1, and the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 was 228 mS/cm. It was

[Comparative Example 6]
At the time of electroplating, electroplating was performed in the same manner as in Example 1 except that the suction flow rate of the plating solution 12 was continuously set to 2 L/min to form an Sn plating film on both surfaces of the plated material 20. Formed. The electroplating was stopped because the maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 became too large by 100 mm due to the suction of the plating solution 12. In addition, when the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 was measured by the same method as in Example 1, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 was 243 mS/cm. It was

[Comparative Example 7]
At the time of electroplating, electroplating was carried out in the same manner as in Example 1 except that the suction flow rate of the plating solution 12 was 0.5 L/min and continuous suction was performed to obtain a thickness on both sides of the plated material 20. A 1.0 μm Sn plating film was formed. The maximum decrease in the height of the liquid level of the plating solution 12 in the anode bag 14 during the suction of the plating solution 12 was 0 mm.

Electroplating is performed in this manner, and after 2 weeks, the conductivity of the supernatant of the plating solution 12 outside the anode bag 14 is measured by the same method as in Example 1, and the plating in the anode bag 14 is performed. The conductivity of the plating solution 12 at a position 300 mm (near the bottom of the anode case 16) vertically downward from the liquid surfaces of the introduction side, the central part and the discharge side of the material 20 was measured, and the plating solution 12 outside the anode bag 14 was measured. The electric conductivity of the supernatant liquid is 238 mS/cm, and the electric conductivity of the plating liquid 12 at a position 300 mm vertically below the liquid surface of the material to be plated in the anode bag 14 on the introduction side, the central part and the discharge side ( The amount of decrease (relative to the conductivity of the supernatant of the plating solution 12 outside the anode bag 14) was 126 mS/cm, 90 mS/cm and 124 mS/cm, respectively. Further, when the difference between the maximum value and the minimum value of the thickness of the Sn plating film in the width direction was obtained by the same method as in Example 1, it was 0.6 μm, and the difference in thickness was large.

The conditions and results of these Examples and Comparative Examples are shown in Tables 1 and 2.

10 Plating Tank 12 Plating Solution 14 Anode Bag 16 Anode Case 18 Anode Ball 20 Plated Material 22 Suction Pipe 22a Suction Port 24 Plate Material 26 Anode Bar 28 Sludge

Claims (9)

While transporting a long strip-shaped material to be plated along its longitudinal direction in the plating tank so that its width direction is substantially vertical, the anode in the anode bag is placed in the plating solution in the plating tank. In the electroplating method, in which a current is passed between the anode and the material outside the anode bag to plate the material to be plated, a suction tube is introduced into the anode bag, and the height of the lowermost end of the suction port of the suction tube is increased. the liquid surface of but arranged anode lowermost than vertically above the height of the a and and the suction port so that a lowermost end below the height 70mm anode, when plating a material to be plated, the plating solution Of the plating solution is sucked from the suction port while maintaining the maximum decrease in the height of 1 to 60 mm, and then the suction of the plating solution is stopped alternately, thereby intermittently discharging a part of the plating solution. The method of electroplating is characterized in that it is sucked and discharged from the plating tank. The electroplating method according to claim 1, wherein the anode is a plurality of anode balls housed in an anode case in the anode bag. A plurality of the anodes are housed in each of two anode cases that are arranged in the anode bag and are spaced apart from each other in a direction substantially perpendicular to the vertical direction and substantially parallel to a surface facing the material to be plated. 2. The electroplating method according to claim 1, wherein the electroplating method is the anode ball. The electroplating method according to claim 3, wherein the suction port of the suction tube is arranged between the side surfaces of the two anode cases. 5. The suction time of each of the plating solutions at the time of intermittently sucking a part of the plating solution is shorter than the stop time of each suction of the plating solution. The electroplating method as described in 1. The electroplating method according to claim 5, wherein the suction time of each of the plating solutions is 10 to 250 seconds, and the suction stop time of each of the plating solutions is 300 to 2000 seconds. The electroplating method according to claim 1, wherein the anode is arranged so as to face at least one surface of a material to be plated. The electroplating method according to claim 1, wherein the plating is Sn plating. The suction port of the suction pipe is arranged at a substantially central portion of the anode bag in a direction substantially perpendicular to a vertical direction and in a direction substantially parallel to a surface facing the material to be plated. The electroplating method according to any one of claims 1 to 7.

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