Method for processing foil-like materials

Abstract

This invention provides a method for processing foil-like materials, such as extremely thin metal foils, that enables uniform and efficient blast processing of both sides without causing warping or distortion. [Solution] A method for processing a foil-like material, comprising a blasting process in which a slurry containing granules and liquid is projected onto both the front and back surfaces of the foil-like material, the method comprising: a tensioning step of applying a predetermined tension in the longitudinal direction of the foil-like material; and a blasting step of simultaneously projecting the slurry onto a linear processing section formed along the width direction of the foil-like material using a pair of nozzle members arranged on the front and back surfaces of the foil-like material.

Description

Technical Field

[0001] The present invention relates to a method for treating a foil-shaped body such as a copper foil, an aluminum foil, or a stainless steel foil by wet blasting in which a mixed fluid (slurry) of an abrasive and a liquid is projected onto the foil-shaped body to perform a surface treatment, and more particularly to a method for treating a foil-shaped body that prevents curling and warping of the foil-shaped body after treatment.

Background Art

[0002] In optical components such as cameras and sensors, reflection suppression foils for suppressing reflection, copper foils for circuit formation of printed wiring boards, metal foils for current collectors such as lithium ion secondary batteries and all-solid-state batteries, and electronic components such as electrolytic capacitors, etc., for various purposes such as improving adhesion to resin layers and active material layers, a treatment for roughening the surface of the foil-shaped body is performed. As one such roughening treatment, blast processing in which abrasive particles are projected by compressed air is known. In recent years, the wet blasting method in which fine abrasives are mixed with a liquid such as water and projected has attracted attention because there is no scattering of dust and more uniform and precise processing is possible.

[0003] Conventionally, as a method for continuously treating this type of long foil-shaped body, a method in which the foil-shaped body is conveyed in the horizontal direction and the abrasive is projected from above it is common. As such a treatment method, various methods are known. For example, as the treatment method described in Patent Document 1, it is known to project a slurry, which is a mixture of a liquid and granular bodies, onto a thin workpiece to perform rolling treatment on the foil-shaped workpiece.

[0004] According to such a method for treating a foil-shaped body, there is an effect that an extremely thin foil-shaped body (for example, an ultra-thin metal foil such as a copper foil or an aluminum foil) can be obtained simply and surely.

[0005] However, it is known that when blast processing is performed on a thin foil-shaped body, compressive residual stress is generated on the surface of the foil-shaped body due to the impact energy of the abrasive, and elongation due to microscopic plastic deformation occurs.

[0006] In this case, when processing is applied to only one side of the foil-like material 101 by a nozzle member 112 positioned on one side of the foil-like material 101, as shown in Figure 8, elongation occurs only on the processed side. This causes the entire foil-like material 101 to curve into a shape with the processed side convex, or to warp (curl) along its longitudinal direction due to the so-called bimetallic effect. This warping is particularly pronounced in ultra-thin foils with a thickness of several tens of micrometers or less, leading to poor handling in subsequent processes and defects during lamination.

[0007] To solve these problems, for example, Patent Document 2 discloses a method for manufacturing a foil without warping by sandblasting both sides of the metal foil so that the surface and back sides are under the same conditions. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2005-342730 [Patent Document 2] Japanese Patent Publication No. 54-102683 [Overview of the project] [Problems that the invention aims to solve]

[0009] However, while the technology described in Patent Document 2 was effective for relatively thick rigid aluminum foil of about 0.07 mm in thickness, when the same method was applied to extremely thin stainless steel foil of about 0.02 mm in thickness, which has seen increasing demand in recent years, it presented the challenge of difficulty in producing foil without warping.

[0010] Furthermore, in the method described in Patent Document 1, where one side is processed at a time, the foil's condition differs between the first processed side and the opposite side. Therefore, even if processed under the same conditions, warping cannot be eliminated, and precise adjustments to the conditions are necessary. In addition, simply processing both sides makes it difficult to maintain symmetry and apply uniform stress while keeping both sides symmetrical, as thin foils are prone to vibration and displacement due to blast pressure.

[0011] The present invention has been made in view of the above problems, and aims to provide a method for processing foil-like materials that can uniformly and efficiently blast-treat both sides of even extremely thin foil-like materials such as metal foils without causing warping or distortion. [Means for solving the problem]

[0012] A method for processing a foil-like body according to the present invention to solve the above problems is a method for processing a foil-like body by projecting a slurry in which granules and liquid are mixed onto both the front and back surfaces of the foil-like body to perform blast processing, characterized in that it comprises a tension application step of applying a predetermined tension in the longitudinal direction of the foil-like body, and a blasting step of simultaneously projecting the slurry onto a linear processing section formed along the width direction of the foil-like body using a pair of nozzle members arranged on the front and back surfaces of the foil-like body.

[0013] Furthermore, in the method for processing a foil-like body according to the present invention, it is preferable that the pair of nozzle members are arranged point-symmetrically with respect to the linear processing section in the longitudinal cross-section, and that the projection angle of the slurry is ±75° with respect to the foil-like body.

[0014] Furthermore, in the method for processing a foil-like material according to the present invention, it is preferable to include a moving step of moving the linear processing section in parallel along the longitudinal direction.

[0015] Furthermore, in the method for processing a foil-like body according to the present invention, it is preferable that the pair of nozzle members be equipped with angle adjustment means capable of changing the projection angle.

[0016] Furthermore, in the method for processing a foil-like body according to the present invention, the moving step preferably involves moving the foil-like body along the longitudinal direction.

[0017] Furthermore, in the method for processing a foil-like body according to the present invention, it is preferable that the tension is applied in the tension-applying step by stretching the foil-like body in the moving step.

[0018] Furthermore, in the method for processing a foil-like body according to the present invention, the moving step preferably involves the nozzle member moving along the longitudinal direction.

[0019] Furthermore, in the method for processing a foil-like body according to the present invention, it is preferable that the nozzle member has a projection opening for projecting the slurry that is slit-shaped and extends in the width direction of the foil-like body, and that the slurry is projected in a strip-like manner from the projection opening.

[0020] Furthermore, in the method for processing foil-like materials according to the present invention, the granules are preferably abrasive materials with a grit of #320 or less. [Effects of the Invention]

[0021] The method for processing a foil-like material according to the present invention comprises a tension-applying step of applying a predetermined tension in the longitudinal direction of the foil-like material, and a blasting step of simultaneously projecting slurry onto a linear processing section formed along the width direction of the foil-like material using a pair of nozzle members arranged on the front and back sides of the foil-like material. By processing the linear processing section of the foil-like material from both the front and back sides simultaneously, both sides undergo the same plastic deformation at the same time, and stress remains symmetrically inside, thus suppressing the occurrence of warping. Furthermore, since the processing is performed with tension applied to the foil-like material, the stress on the foil surface during blasting becomes constant, and the processing conditions are made uniform. In addition, because plastic deformation becomes easier in the direction in which tension is applied beforehand, the direction of elongation of the foil becomes uniform, and warping and distortion caused by random elongation in all directions can be prevented. [Brief explanation of the drawing]

[0022] [Figure 1]Perspective view of a processing apparatus for performing a method of processing a foil-like body according to an embodiment of the present invention. [Figure 2] Diagram for explaining the outline of a method of processing a foil-like body according to an embodiment of the present invention. [Figure 3] Perspective view showing a nozzle member used in a method of processing a foil-like body according to an embodiment of the present invention. [Figure 4] Diagram showing a modified example of a processing apparatus for performing a method of processing a foil-like body according to an embodiment of the present invention. [Figure 5] Graph showing the relationship between the tension applied to the foil-like body and the warp of the foil-like body. [Figure 6] Graph showing the relationship between the deviation amount of the nozzle member and the warp of the foil-like body. [Figure 7] Graph showing the relationship between the projection angle and the warp of the foil-like body. [Figure 8] Diagram for explaining the state in which the foil-like body warps.

Mode for Carrying Out the Invention

[0023] Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the invention according to each claim, and not all combinations of the features described in the embodiments are essential for the solution means of the invention.

[0024] FIG. 1 is a perspective view of a processing apparatus for performing a method of processing a foil-like body according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the outline of a method of processing a foil-like body according to an embodiment of the present invention, FIG. 3 is a perspective view showing a nozzle member used in a method of processing a foil-like body according to an embodiment of the present invention, FIG. 4 is a diagram showing a modified example of a processing apparatus for performing a method of processing a foil-like body according to an embodiment of the present invention, FIG. 5 is a graph showing the relationship between the tension applied to the foil-like body and the warp of the foil-like body, FIG. 6 is a graph showing the relationship between the deviation amount of the nozzle member and the warp of the foil-like body, and FIG. 7 is a graph showing the relationship between the projection angle and the warp of the foil-like body.

[0025] (Configuration of the processing apparatus) As shown in Figure 1, the processing apparatus 10 for processing a foil-like body according to this embodiment includes a tension-applying mechanism 11 that performs a tension-applying step of applying tension to the foil-like body 1, and a pair of nozzle members 12 that perform a blasting step of projecting slurry onto a linear processing section L formed on the surface of the foil-like body 1.

[0026] The foil-like material 1 processed by the foil-like material processing method according to this embodiment can be any of the conventionally known foil-like materials, but for example, an extremely thin stainless steel foil with a thickness of about 0.02 mm is preferably used.

[0027] The tension-applying mechanism 11 can employ various conventionally known configurations as long as it can apply a predetermined tension in the longitudinal direction of the foil-like body 1. For example, it is preferable to have a gripping part 14 that grips one end of the foil-like body 1 and a spring part 15 that pulls the other end in the longitudinal direction. The method of applying tension is not limited to the above-described form. For example, as shown in Figure 4, tension may be applied to the foil-like body 1 using the tensile force F when the foil-like body 1 is gripped and fed by the roller 21 that conveys the roll 20 of the foil-like body 1. It has been confirmed that the greater the tension applied to the foil-like body 1, the less warping occurs. Therefore, it is preferable to apply a tension of, for example, 9N to 145N, such that the foil-like body 1 does not tear.

[0028] It is preferable to use a pair of nozzle members 12, such as the one shown in Figure 2, as the nozzle member 12. As shown in Figure 3, this nozzle member 12 has a linearly extending slit-shaped projection opening 16, and as shown in Figure 2, the slit-shaped projection openings 16 are arranged opposite each other so that their extending directions are parallel to each other.

[0029] Furthermore, the nozzle member 12 is attached to a moving mechanism to which an angle adjustment means (not shown) is attached. The moving mechanism holds the pair of nozzle members 12 along the frame 13 so that they can be simultaneously moved in a direction perpendicular to the extending direction of the projection port 16, that is, in the longitudinal direction of the foil-like body 1. The moving mechanism can be configured in any way as long as it can move the nozzle members 12 in parallel, but for example, various conventional actuators such as linear guide devices and ball screws, or conventional moving mechanisms using timing belts can be used.

[0030] As shown in Figure 3, the nozzle member 12 projects the projection material S in a strip shape from a linearly extending slit-shaped projection opening 16. The nozzle member 12 comprises a nozzle member body 19 having a slurry inlet 17 for introducing slurry, which is the projection material S, and an air inlet 18 for introducing compressed air, and a slit-shaped projection opening 16 that extends vertically from the nozzle member body 19. The slurry and compressed air introduced from the slurry inlet 17 and air inlet 18 are stored in a slurry storage chamber and an air storage chamber inside the nozzle member body 19, mixed in an internal passage connecting the slurry storage chamber and the air storage chamber, and projected as the projection material S in a strip shape from the slit-shaped projection opening 16.

[0031] The abrasive material S is preferably projected as a slurry, which is a mixture of liquid and abrasive particles, along with compressed air. The liquid contained in the slurry serves to transport the abrasive particles, described later, to the surface of the workpiece. Therefore, any liquid can be used as long as it can perform this role, except for flammable substances. Specifically, water is preferred due to environmental considerations and cost considerations.

[0032] The abrasive grains are transported to the workpiece surface by the liquid and play the role of performing the desired processing on the workpiece surface. Therefore, any abrasive grains can be used as long as they can perform this role.

[0033] Specifically, examples of abrasive material include ceramics, resins, and metals, and more specifically, alumina, glass, zirconia, and stainless steel. Examples of abrasive shape include polygonal, spherical, and perfectly spherical shapes. The size of the abrasive grains can be appropriately selected and used from approximately 1 μm to 500 μm. For processing thin foils like foil 1 in the foil processing method according to this embodiment, finer particles are more suitable, and it is desirable to use abrasives of #320 (JIS R 6001 (abrasive grain size)) (approximately 98-27 μm) or smaller.

[0034] The proportion of abrasive grains in the total slurry is not particularly limited and can be appropriately designed according to the material of the workpiece, the processing area, and the desired degree of processing.

[0035] Furthermore, the slurry can be a mixture of various functional materials in addition to the liquid and abrasive grains mentioned above, and may contain, for example, a rust inhibitor. By including a rust inhibitor in the slurry used in the wet blasting treatment method, it becomes possible to apply a conventional wet blasting treatment to the surface of the workpiece while simultaneously providing a rust-preventive effect. Alternatively, various additives may be added instead of a rust inhibitor, as long as they do not hinder the effects of each component.

[0036] Next, each step of the processing method for the foil-like material according to this embodiment will be described.

[0037] (Tensioning process) Prior to or simultaneously with the blasting process, a tension-applying mechanism applies a predetermined tension (e.g., 10N to 150N) in the longitudinal direction of the foil-like body 1. Applying tension restricts the direction in which the foil stretches when subjected to blasting, thereby suppressing the occurrence of localized distortion.

[0038] (Blasting process) In the process of applying tension to the foil-like body 1, which has been subjected to tension, slurry is simultaneously projected onto the linear processing section L from nozzle members 12 positioned on both the front and back surfaces. The linear processing section L is formed on both the front and back surfaces in the longitudinal cross-section of the foil-like body 1, and the slurry is projected simultaneously so as to sandwich the linear processing section L from both sides.

[0039] The slurry is projected onto both the front and back surfaces of the linear processing section L at approximately the same projection angle and projection pressure. Here, the projection angle θ refers to the angle of the projection axis of the slurry from the nozzle member 12 to the surface of the foil-like body 1, as shown in Figure 2. It is most preferable that this projection angle θ is perpendicular to the surface of the foil-like body 1, that is, coincides with the normal direction of the surface of the foil-like body 1. This is because if the projection angle θ is not perpendicular, when the foil-like body 1 is displaced by blast pressure or the like, the collision position of the slurry on the front and back surfaces may shift, potentially disrupting the stress symmetry.

[0040] However, in practical terms, within a range of ±15° from the perpendicular (90°) (i.e., a range of 75° to 105° relative to the surface of the foil), the effect of opposing arrangement can be obtained, and the occurrence of warping can be suppressed.

[0041] Furthermore, it is preferable that the width of the strip-shaped slurry be equal to or longer than the length of the linear processing section L, i.e., the width dimension of the foil-like body 1. By projecting the slurry in this way, the slurry can be reliably projected all the way to the edge of the foil-like body 1.

[0042] It is desirable that the pair of nozzle members 12 be positioned point-symmetric with respect to the foil-like body 1 in a cross-section along the longitudinal direction of the foil-like body 1, that is, in positions where the projection directions of the slurry projected onto them are opposite each other in the linear processing section L. As will be described later, it has been found that if the amount of displacement along the longitudinal direction of the positions where the pair of nozzle members 12 project onto the linear processing section L exceeds 3 mm, the effect on the warping of the foil-like body 1 becomes significant.

[0043] (Moving process) In the processing, the entire surface of the foil-like body 1 is processed by moving the linear processing unit L relative to the longitudinal direction. Specifically, as shown in Figure 1, the foil-like body may be fixed and the nozzle member may be scanned (moved), or as shown in Figure 4, the nozzle member 12 may be fixed and the foil-like body 1 may be transported (moved). From the viewpoint of continuous production, the configuration in which a long foil-like body 1 is transported roll-to-roll while being processed, as shown in Figure 4, is suitable. [Examples]

[0044] To confirm the effects of the present invention, stainless steel foil was processed under the following conditions. In this embodiment, a processing apparatus 10 as shown in Figure 1 was used, specifically, a pair of nozzle members 12 having linearly extending slit-shaped projection openings 16, and this apparatus was used in which the pair of nozzle members 12 were arranged opposite each other with a foil-like body 1 in between. The projection angle θ of these nozzle members 12 can be adjusted by angle adjustment means, and their positions are adjusted so that the extension lines of the slurry projected from the projection openings 16 intersect at the same point on the foil-like body 1.

[0045] The processing conditions are as follows: <Processing conditions> • Material to be processed: Stainless steel foil (thickness 0.02 mm, width 150 mm) • Abrasive material: Alumina polygon #800 (particle size approximately 38-9 μm) • Nozzle component configuration: Projection port shape: Slit-shaped (1 x 160 mm) • Arrangement of nozzle components: Arranged opposite each other on the front and back sides of the foil-like material (point-symmetric arrangement) • Projection angle θ of the nozzle component: Perpendicular to the surface of the foil-like material (90°) • Air pressure: 0.23 MPa • Processing method: With tension applied to the foil-like body 1 in the longitudinal direction by a tension-applying mechanism, a slurry was simultaneously projected in a strip shape from a pair of nozzle members 12 to form a linear processing section L. At this time, the entire surface was processed by moving the nozzle members 12 relative to the foil-like body 1 at a constant speed in the longitudinal direction.

[0046] As a result of processing under the above conditions, even an ultra-thin stainless steel foil with a thickness of 0.02 mm could be successfully blast-treated without warping or distortion. This is thought to be because the stress balance inside the foil was maintained at a high degree of symmetry in the thickness direction due to the synergistic effect of the arrangement of a pair of nozzle members 12 with slit-shaped projection openings 16 facing each other, the simultaneous impact of the slurry on the linear processing areas L formed at the same positions on both the front and back surfaces of the foil using angle adjustment means, and the application of tension. In addition, since a uniform band-shaped slurry was projected from the slit-shaped projection openings 16 in the width direction, uniform processing was also achieved in the width direction of the foil 1, which contributed to the results.

[0047] Furthermore, as shown in Figure 5, it was confirmed that the greater the tension applied to the foil-like body 1 by the tension-applying means, the less warping occurs, as long as the tension is large enough that the foil-like body 1 is not damaged or broken. In Figure 5, the warping of the foil-like body 1 was measured when tension from 9N to 145N was applied and slurry was projected onto the linear processing section L on both sides simultaneously by the nozzle member.

[0048] Furthermore, it was confirmed that performing multiple processes by reciprocating movement at a high speed (e.g., 200 mm / s) of the linear processing unit L (in this embodiment, the movement speed of the nozzle member 12) suppresses the occurrence of warping more effectively than performing a single process at a low speed (e.g., 20 mm / s).

[0049] Furthermore, as shown in Figure 6, it was confirmed that the amount of displacement (offset) along the longitudinal direction of the slurry projected from the pair of nozzle members 12 has little effect on warping as long as it is within the thickness range of the strip-shaped slurry, and that warping can be suppressed if the amount of displacement is less than 3 mm.

[0050] Furthermore, as shown in Figure 7, it was confirmed that when the projection angle θ is reduced from 90° (rotating in a direction that brings the nozzle member 12 closer to the surface of the foil-like body 1) with the nozzle member 12 positioned point-symmetrically, the occurrence of warping gradually increases. It was confirmed that warping can be sufficiently suppressed at an angle of approximately 75°.

[0051] Thus, according to the method for processing foil-like materials based on the present invention, the occurrence of warping can be suppressed and processing conditions can be made uniform.

[0052] Furthermore, although the nozzle member 12 in this embodiment has been described in the case where processing is performed using a pair of nozzle members 12, multiple pairs of nozzle members 12 may be arranged along the longitudinal direction of the foil-like body 1. For example, when processing a long foil-like body 1 as shown in Figure 4 while conveying it roll-to-roll, processing with multiple pairs of nozzle members 12 makes it possible to perform multiple processing steps, similar to the case where the nozzle members 12 are moved back and forth as in the processing apparatus 10 shown in Figure 1. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention. [Explanation of symbols]

[0053] 1 Foil-like body, 10 Processing device, 11 Tensioning mechanism, 12 Nozzle member, 13 Frame, 14 Gripping part, 15 Spring part, 16 Projection port, 17 Slurry inlet, 18 Air inlet, 19 Nozzle member body, 20 Roll, L Linear processing part, F Tensile force, S Projection material

Claims

1. A method for processing a foil-like material, which involves blasting a slurry containing a mixture of granules and liquid onto both the front and back surfaces of the foil-like material, A tension application step of applying a predetermined tension in the longitudinal direction of the foil-like body, A blasting step in which the slurry is simultaneously projected onto a linear processing section formed along the width direction of the foil-like body by a pair of nozzle members arranged on the front and back sides of the foil-like body, A method for processing a foil-like material, characterized by comprising the following:

2. In the method for processing a foil-like material according to claim 1, The pair of nozzle members are arranged point-symmetrically with respect to the linear processing section in the longitudinal cross-section. A method for processing a foil-like material, characterized in that the projection angle of the slurry is ±75° with respect to the foil-like material.

3. In the method for processing a foil-like material according to claim 1, A method for processing a foil-like body, characterized by comprising a movement step of moving the linear processing unit parallel to the longitudinal direction.

4. In the method for processing a foil-like material according to claim 3, The method for processing a foil-like body is characterized in that the moving step involves moving the foil-like body along the longitudinal direction.

5. In the method for processing a foil-like body according to claim 4, A method for processing a foil-like body, characterized in that the tension-applying step is performed by stretching the foil-like body by the moving step.

6. In the method for processing a foil-like material according to claim 3, The method for processing a foil-like body is characterized in that the moving step involves the nozzle member moving along the longitudinal direction.

7. In the method for processing a foil-like material according to claim 1, The nozzle member has a projection opening for projecting the slurry that is formed in the shape of a slit extending in the width direction of the foil-like body, A method for processing a foil-like body, characterized in that the slurry is projected in a strip shape from the projection port.

8. In the method for processing a foil-like material according to claim 1, A method for processing a foil-like body, characterized in that the granular material is an abrasive with a grit of #320 or less.

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