JP5770113B2 - Metal foil composite, molded body and method for producing the same - Google Patents

Description

The present invention is a metal foil composite body formed by laminating a metal foil and a resin layer, as well as moldings and a method for producing the same.

Metal foil composites made by laminating metal foil and resin layers are applied to FPC (flexible printed circuit boards), electromagnetic shielding materials, RF-ID (wireless IC tags), planar heating elements, heat radiators, etc. . For example, in the case of FPC, a circuit of metal foil is formed on a base resin layer, and a coverlay film that protects the circuit covers the circuit, and has a laminated structure of resin layer / metal foil / resin layer.
Metal foil laminates obtained by laminating Cu foil or Al foil and resin are applied to electromagnetic wave shielding materials, reflectors for lighting equipment, and the like. A laminate using an Al foil may be used as an inexpensive circuit material.
By the way, as a workability of such a metal foil composite, a bendability represented by MIT bendability and a high cycle bendability represented by IPC bendability are required, and a metal foil excellent in bendability and bendability. Complexes have been proposed (for example, Patent Documents 1 to 3). For example, FPC can be bent at a movable part such as a hinge part of a mobile phone, or it can be bent to reduce the circuit space. Deformation modes include the MIT bending test and the IPC bending test described above. As represented, it is uniaxial bending and is designed not to be in a severe deformation mode.

JP 2010-100877 A JP 2009-111203 A JP 2007-207812 A

However, when the above metal foil composite is pressed or the like, a severe (complex) deformation mode different from the MIT bending test or the IPC bending test is brought about, so that there is a problem that the metal foil is broken. If the metal foil composite can be pressed, the structure including the circuit can be matched to the product shape.
Accordingly, an object of the present invention are single bend different severe (complex) deformation be performed to prevent the metal foil is broken, excellent formability metal foil composites such as press working or the like, as well as moldings And a manufacturing method thereof.

The present inventors transmit the deformation behavior of the resin layer to the metal foil, and by deforming the metal foil in the same manner as the resin layer, the metal foil is less likely to be constricted and the ductility is improved. The inventors have found that this can be prevented, and have reached the present invention. That is, the characteristics of the resin layer and the metal foil were defined so that the deformation behavior of the resin layer was transmitted to the metal foil.
That is, the metal foil composite of the present invention has a thickness of 50 μm or less, a fracture strain of 4% or more , and one or more selected from the group consisting of Ag, Sn, In, Au, Mn, Ni, and Zn. In a copper foil containing a total of 30 ppm to 500 ppm , the average crystal grain size is 10 μm or more, and the crystal grain size exceeds 10 μm, the crystal grain of the copper foil observed from the surface of the copper foil The ratio R expressed by: (average value of the diameter of the maximum inscribed circle) / (average value of the diameter of the minimum circumscribed circle of the crystal grains of the copper foil observed from the surface of the copper foil) is 0.5 ≦ R ≦ 0.8 A metal foil composite in which a filling copper foil and a resin layer having a thickness of 120 μm or less are laminated, wherein the thickness of the copper foil is t ₂ (mm), and the stress of the copper foil at a tensile strain of 4% is f ₂ ( MPa), where the thickness of the resin layer is t ₃ (mm), and the stress of the resin layer at a tensile strain of 4% is f ₃ (MPa), Equation 1: (f ₃ × t ₃ ) / (F ₂ × t ₂ ) ≧ 1, and the 180 ° peel adhesion strength between the copper foil and the resin layer is f ₁ (N / mm), and the strength at 30% tensile strain of the metal foil composite Is F (MPa), and the thickness of the metal foil composite is T (mm), the formula 2: 1 ≦ 33f ₁ / (F × T) is satisfied.

It is preferable that Formula 1 and Formula 2 hold at a temperature lower than the glass transition temperature of the resin layer.
It is preferable that the ratio 1 / L between the tensile breaking strain 1 of the metal foil composite and the tensile breaking strain L of the resin layer alone is 0.7-1.

The molded body of the present invention is obtained by processing the metal foil composite. The molded body of the present invention can be three-dimensionally processed by, for example, pressing, overhanging using upper and lower molds, or other processing for drawing.
The manufacturing method of the molded object of this invention processes the said metal foil composite.

  According to the present invention, it is possible to prevent the metal foil from cracking even when severe (complex) deformation different from uniaxial bending such as pressing is performed, and to obtain a metal foil composite excellent in workability.

It shows experimentally the relationship f ₁ and (F × T). It is a figure which shows the structure of the cup test apparatus which performs workability evaluation.

  The metal foil composite of the present invention is configured by laminating a metal foil and a resin layer. The metal foil composite of the present invention can be applied to, for example, an FPC (flexible printed circuit board), an electromagnetic wave shielding material, an RF-ID (wireless IC tag), a planar heating element, and a radiator, but is not limited thereto. It doesn't mean.

<Metal foil>
The metal foil is made of a copper foil, an aluminum foil, a nickel foil, a stainless steel foil, a mild steel foil, a Fe—Ni alloy foil or a white foil having the following composition.
The copper foil has a composition containing one or more additive elements selected from the group consisting of Ag, Sn, In, Au, Mn, Ni, and Zn in a total mass of 30 ppm to 500 ppm. If it is set as this composition, it can suppress recovering dynamically (or static) at the time of cold rolling of copper foil, or after cold rolling (reduction of a dislocation density). For this reason, when recrystallization is performed by heat treatment after cold rolling, the crystal grain size of the copper foil tends to become coarse, and f ₂ and F can be reduced, and (f ₃ × t ₃ ) / ( f ₂ × t ₂ ) and 33f ₁ / (F × T) can be set to large values, and excellent workability can be obtained when a composite is formed.
When the total content of the additive elements is less than 30 ppm, the above-described effect is small, and when the total content exceeds 500 ppm, the crystal grains are more easily refined when recrystallized, and the strength is increased by alloying. ₂ rises, and (f ₃ × t ₃ ) / (f ₂ × t ₂ ) and 33f ₁ / (F × T) become smaller.

Aluminum foil contains 99% by mass or more of Al, specifically, alloy numbers 1085, 1080, 1070, 1050, 1100, 1200, 1N00, 1N30 described in JIS H 4000, Al: 99.00% by mass or more Aluminum is soft and preferred.
The nickel foil contains 99 mass% or more of Ni, and specifically, Ni foil of 99.0 mass% or more represented by alloy numbers NW2200 and NW2201 described in JIS H4551 is soft and preferable.
The stainless steel foil is preferably a stainless steel foil made of any one of SUS301, SUS304, SUS316, SUS430, and SUS631 (all JIS standards) that can reduce the plate thickness.
The mild steel foil is preferably a soft mild steel having 0.15% by mass or less of carbon, and is preferably produced based on the steel sheet described in JIS G3141.
The Fe—Ni alloy foil contains 35 to 85% by mass of Ni, and the balance is considerably Fe and inevitable impurities. Specifically, an alloy foil can be produced based on the Fe—Ni alloy described in JIS C2531. preferable.
The white is preferably a foil made of alloy numbers C7351, C7521 and C7541 described in JIS H 3110.

The thickness _{t 2} of the metal foil is preferably 0.004~0.05mm (4~50μm). t ₂ is decreased significantly the ductility of the metal foil is less than 0.004 mm (4 [mu] m), there is a case where workability of the metal foil composite is not improved. The metal foil preferably has a tensile breaking strain of 4% or more. If t ₂ is more than 0.05 mm (50 [mu] m), the influence of the metal foil single properties when the metal foil composite appears large, there is a case where workability of the metal foil composite is not improved.
As the metal foil, a rolled metal foil, an electrolytic metal foil, a metal foil made of metallization, or the like can be used, and a rolled metal foil that can reduce strength (f ₂ ) while being excellent in workability by recrystallization is preferable. If a treatment layer for adhesion and rust prevention is formed on the surface of the metal foil, these are also included in the metal foil.

<Resin layer>
The resin layer is not particularly limited, and a resin layer may be formed by applying a resin material to a metal foil, but a resin film that can be attached to the metal foil is preferable. Examples of the resin film include PET (polyethylene terephthalate) film, PEN (polyethylene naphthalate), PI (polyimide) film, LCP (liquid crystal polymer) film, and PP (polypropylene) film.
As a method for laminating the resin film and the metal foil, an adhesive may be used between the resin film and the metal foil, or the resin film may be thermocompression bonded to the metal foil. In addition, if the strength of the adhesive layer is low, it is difficult to improve the workability of the metal foil composite. Therefore, the strength of the adhesive layer is preferably 1/3 or more of the stress (f ₃ ) of the resin layer. In the present invention, the technical idea is that the deformation behavior of the resin layer is transmitted to the metal foil, and the metal foil is also deformed in the same manner as the resin layer, so that the metal foil is hardly constricted and the ductility is improved. This is because if the strength of the adhesive layer is low, deformation is relaxed by the adhesive layer, and the behavior of the resin is not transmitted to the metal foil.
In addition, when using an adhesive agent, the characteristic of the resin layer mentioned later targets what combined the adhesive bond layer and the resin layer.

The thickness t _{3 of the} resin layer is preferably 0.012 to 0.12 mm (12 to 120 μm). If t ₃ is less than 0.012 mm (12 μm), (f ₃ × t ₃ ) / (f ₂ × t ₂ ) <1 in some cases. When t ₃ is thicker than 0.12 mm (120 [mu] m), too high rigidity decreases the flexibility of the resin layer (flexibility) is, workability is deteriorated. The resin layer preferably has a tensile breaking strain of 40% or more.

<Metal foil composite>
As a combination of the metal foil composite in which the metal foil and the resin layer are laminated, the two-layer structure of metal foil / resin layer, resin layer / metal foil / resin layer, or metal foil / resin layer / metal foil A three-layer structure is mentioned. When resin layers exist on both sides of the metal foil (resin layer / metal foil / resin layer), the total value of (f ₃ × t ₃ ) is calculated for each of the two resin layers (f ₃ × t ₃ ) The value of ₃ ) shall be added. When metal foil exists on both sides of the resin layer (metal foil / resin layer / metal foil), the total value of (f ₂ × t ₂ ) is calculated for each of the two metal foils (f ₂ × t _It is assumed that the value of ₂ ) is added.

<180 ° peel strength>
Since the metal foil is thin, it tends to be constricted in the thickness direction. When the constriction occurs, the metal foil breaks, and the ductility decreases. On the other hand, the resin layer has a feature that it is difficult for necking to occur when it is pulled (the region of uniform strain is wide). Therefore, in the composite of metal foil and resin layer, the deformation behavior of the resin layer is transmitted to the metal foil, and the metal foil is also deformed in the same way as the resin, so that the metal foil is less likely to be constricted and the ductility is improved. To do. At this time, if the adhesive strength between the metal foil and the resin layer is low, the deformation behavior of the resin layer cannot be transmitted to the metal foil, and the ductility is not improved (peeling and cracking copper).
Therefore, it is necessary to increase the adhesive strength. As for adhesive strength, shear adhesive strength is considered to be a direct indicator. However, if the adhesive strength is increased and the shear adhesive strength is set to the same level as the strength of the metal foil composite, measurement is performed because the location other than the adhesive surface breaks. Becomes difficult.

For this reason, the value of 180 ° peel adhesion strength f ₁ is used in the present invention. Although the absolute values of shear bond strength and 180 ° peel adhesive strength are completely different, there was a correlation between workability, tensile elongation, and 180 ° peel adhesive strength. It was used as an index.
Here, in reality, it is considered that “strength at break = shear adhesion strength”. For example, when a tensile strain of 30% or more is required, “30% flow stress ≦ shear adhesion” When the tensile strain of 50% or more is required, it is considered that “50% flow stress ≦ shear adhesion”. And, according to the experiments by the present inventors, the workability was improved when the tensile strain was 30% or more, and as described later, the strength at the tensile strain of 30% was adopted as the strength F of the metal foil composite. It is said.

Figure 1 is a diagram showing experimentally the relationship f ₁ and (F × T), are plotted the values of f ₁ of each of the following examples and comparative examples (F × T). (F × T) is a force applied to the metal foil composite with a tensile strain of 30%. When this is regarded as the minimum shear adhesive strength necessary for improving the workability, f ₁ and (F × T ) Have the same absolute value, they are correlated with a slope of 1.
However, in FIG. 1, f ₁ and (F × T) of all data do not have the same correlation, and each comparative example with inferior workability has a correlation coefficient of f ₁ with respect to (F × T) (that is, , through the origin of Figure 1, it is inferior f ₁ gradient) is small relative to it by 180 ° peel adhesive strength (F × T). On the other hand, the slope of each example is larger than the slope of each comparative example, but the slope of Example 22 with the smallest slope (just broken at 30% strain) was 1/33. The correlation coefficient between the minimum shear bond strength and 180 ° peel bond strength required to improve That is, the shear adhesive strength was regarded as 33 times the 180 ° peel adhesive strength f _1.
In the case of Comparative Examples 3, 6, and 10, the slope of FIG. 1 exceeded 1/33, but the expression 1: (f ₃ × t ₃ ) / (f ₂ × t ₂ ) described later is less than 1. Therefore, workability has deteriorated.
In FIG. 1, ◯ indicates an example and × indicates a comparative example.

The 180 ° peel strength is a force per unit width (N / mm).
When the metal foil composite has a three-layer structure and there are a plurality of adhesion surfaces, the value having the lowest 180 ° peel adhesion strength among the adhesion surfaces is used. This is because the weakest adhesive surface peels off. In addition, the copper foil usually has an S surface and an M surface. However, since the S surface is inferior in adhesion, the adhesion between the S surface of the copper foil and the resin is weakened. Therefore, the 180 ° peel adhesion strength of the S surface of the copper foil is often adopted.

As a method of increasing the adhesive strength between the copper foil and the resin layer, a metal oxide surface (surface on the resin layer side) is provided with a Cr oxide layer by chromate treatment, or the metal foil surface is subjected to a roughening treatment, For example, a Cr oxide layer may be provided after Ni is coated on the surface of the metal foil.
The thickness of the Cr oxide layer is preferably 5 to 100 μg / dm ² in terms of Cr weight. This thickness is calculated from the chromium content by wet analysis. The presence of the Cr oxide layer can be determined by whether or not Cr can be detected by X-ray photoelectron spectroscopy (XPS) (Cr peak is shifted by oxidation).
The Ni coating amount is preferably 90 to 5000 μg / dm ² . When the adhesion amount of Ni coating exceeds 5000 μg / dm ² (corresponding to Ni thickness 56 nm), the ductility of the metal foil (and the metal foil composite) may be lowered.
On the other hand, Al foil, Ni foil, stainless steel foil, mild steel foil, Fe-Ni alloy foil, and white foil have better adhesion to the resin layer compared to copper foil, so even without surface treatment, In many cases, the adhesion is high. However, when these metal foils have low adhesion to the resin layer, the metal foil surface may be subjected to cleaning treatment or plating treatment in order to improve adhesion.
Further, the adhesive strength can be increased by changing the pressure and temperature conditions when the metal foil and the resin layer are laminated and combined. It is better to increase both the pressure and temperature during lamination as long as the resin layer is not damaged.

<(F ₃ × t ₃ ) / (f ₂ × t ₂ )>
Next, the meaning of ((f ₃ × t ₃ ) / (f ₂ × t ₂ )) (hereinafter referred to as “Formula 1”) in the claims will be described. Since the metal foil composite is formed by laminating a metal foil and a resin layer having the same width (dimension), Equation 1 represents a ratio of forces applied to the metal foil and the resin layer constituting the metal foil composite. . Therefore, this ratio of 1 or more means that more force is applied to the resin layer side, and the resin layer side has higher strength than the metal foil. And metal foil shows favorable workability, without fracture | rupturing.
On the other hand, when (f ₃ × t ₃ ) / (f ₂ × t ₂ ) <1, more force is applied to the metal foil side, so that the deformation behavior of the resin layer is transmitted to the metal foil, which is the same as the resin. The above-described action of deforming the metal foil does not occur.
Here, f ₂ and f ₃ may be stresses with the same amount of strain after plastic deformation has occurred, but the tensile fracture strain of the metal foil and the strain at which plastic deformation of the resin layer (eg, PET film) starts. Therefore, the stress is 4% tensile strain. Note that f ₂ and f ₃ (and f ₁ ) are all MD (Machine Direction) values.

<33f ₁ / (F × T)>
Next, the meaning of (33f ₁ / (F × T)) (hereinafter referred to as “Formula 2”) in the claims will be described. As described above, the shear adhesive force directly indicating the minimum adhesive strength between the metal foil and the resin layer, which is necessary for improving the workability, is about 33 times the 180 ° peel adhesive strength f ₁ . 33f ₁ represents the necessary, minimum adhesion strength in order to improve the workability of the metal foil and a resin layer. On the other hand, since (F × T) is a force applied to the metal foil composite, Equation 2 is a ratio between the adhesive strength between the metal foil and the resin layer and the tensile resistance of the metal foil composite. When the metal foil composite is pulled, a shear stress is applied to the interface between the metal foil and the resin layer by the metal foil that is to be locally deformed and the resin that is to be subjected to the tensile uniform strain. Therefore, if the adhesive strength is lower than the shear stress, the copper and the resin layer are peeled off, and the deformation behavior of the resin layer cannot be transmitted to the metal foil, and the ductility of the metal foil is not improved.
That is, when the ratio of Formula 2 is less than 1, the adhesive strength is weaker than the force applied to the metal foil composite, the metal foil and the resin are easily peeled, and the metal foil is broken by processing such as press molding.
If the ratio of Formula 2 is 1 or more, the deformation behavior of the resin layer can be transmitted to the metal foil without peeling off the copper and the resin layer, and the ductility of the metal foil is improved. The higher the ratio of Equation 2, the better. However, since it is usually difficult to achieve a value of 10 or more, the upper limit of Equation 2 should be 10.
Although it is considered that as 33f ₁ / (F × T) is larger, the workability is improved, the tensile strain 1 of the resin layer is not proportional to 33f ₁ / (F × T). This is due to the influence of the size of (f ₃ × t ₃ ) / (f ₂ × t ₂ ), the ductility of the metal foil and the resin layer alone, but 33f ₁ / (F × T) ≧ 1, (f If it is a combination of a metal foil and a resin layer satisfying ₃ × t ₃ ) / (f ₂ × t ₂ ) ≧ 1, a composite having the required workability can be obtained.

Here, the strength at the tensile strain of 30% is used as the strength F of the metal foil composite because the workability is improved when the tensile strain is 30% or more as described above. In addition, when a tensile test of the metal foil composite was performed, a large difference in flow stress was caused by the strain up to 30% tensile strain, but no significant difference in flow stress was caused by the tensile strain after 30% (somewhat This is because the work was hardened but the slope of the curve was considerably reduced.
When the tensile strain of the metal foil composite is not 30% or more, F is the tensile strength of the metal foil composite.

In addition, when metal foil is copper foil, the workability of a metal foil composite is greatly influenced by the crystal grain shape of copper foil. And, if the crystal grains of the copper foil are too small, the workability deteriorates and it is easy to crack, so the average crystal grain is preferably set to 10 μm or more. In addition, when the crystal grains are large, if the shape of the large crystal grains extending in the rolling direction is not isotropic, the workability is deteriorated and the cracks are easily broken. Therefore, in a crystal grain having a crystal grain size exceeding 10 μm, “(average value of the diameter of the maximum inscribed circle of the copper foil crystal grain observed from the plane orientation) / (copper foil crystal grain observed from the plane orientation) It is preferable that the value (ratio) R represented by “the average value of the diameters of the minimum circumscribed circles” is 0.5 or more. The direction where R is close to 1 has an isotropic shape, but the copper foil after rolling tends to have crystal grains extending in the rolling direction, and it was difficult to make R 0.8 or more. The upper limit is usually 0.8 or less.
The crystal grains whose crystal grain size exceeds 10 μm are measured with respect to an area of 0.1 × 0.1 mm on the surface of the copper foil.

  As described above, the metal foil composite of the present invention is excellent in workability by preventing the metal foil from cracking even when severe deformation (complex) different from uniaxial bending such as pressing is performed. In particular, the present invention is suitable for three-dimensional molding such as press working. By forming the metal foil composite in three dimensions, the metal foil composite can be made into a complicated shape or the strength of the metal foil composite can be improved. For example, the metal foil composite itself can be used as a casing for various power supply circuits. The number of parts and cost can be reduced.

<L / L>
The ratio 1 / L between the tensile breaking strain 1 of the metal foil composite and the tensile breaking strain L of the resin layer alone is preferably 0.7-1.
Usually, the tensile rupture strain of the resin layer is overwhelmingly higher than that of the metal foil, and similarly, the rupture strain of the resin layer alone is overwhelmingly higher than that of the metal foil composite. On the other hand, in the present invention, as described above, the deformation behavior of the resin layer is transmitted to the metal foil to improve the ductility of the metal foil, and accordingly, the tensile fracture strain of the metal foil composite is reduced to the tensile fracture of the resin layer alone. The strain can be improved to 70 to 100%. And press ratio is further improved as ratio l / L is 0.7 or more.
The tensile breaking strain l of the metal foil composite is the tensile breaking strain elongation when the tensile test is performed, and is the value when the resin layer and the metal foil are simultaneously broken, and when the metal foil is broken first. Is the value when the metal foil breaks. In addition, when the resin layer has a resin layer on both sides of the metal foil, the tensile break strain L of the resin layer alone is measured by performing a tensile test on each of both resin layers, Let L be. When there are resin layers on both surfaces of the metal foil, the measurement is performed for each of the two resin layers generated by removing the metal foil.

<Tg of resin layer>
Usually, since the strength and the adhesive strength of the resin layer are reduced at high temperature, (f ₃ × t ₃ ) / (f ₂ × t ₂ ) ≧ 1 or 1 ≦ 33f ₁ / (F × T) at high temperature. It becomes difficult to satisfy. For example, at a temperature equal to or higher than the Tg (glass transition temperature) of the resin layer, it may be difficult to maintain the strength and adhesive strength of the resin layer. It tends to be easier to maintain. That is, if the temperature is less than Tg (glass transition temperature) of the resin layer (for example, 5 ° C. to 215 ° C.), the metal foil composite is (f ₃ × t ₃ ) / (f ₂ × t ₂ ) ≧ 1, and It becomes easy to satisfy 1 ≦ 33f ₁ / (F × T). Even at a temperature lower than Tg, it is considered that the higher the temperature, the lower the strength and adhesion of the resin layer, and it tends to be difficult to satisfy Equations 1 and 2 (see Examples 20-22 described later).
Furthermore, when satisfy | filling Formula 1 and Formula 2, it turned out that the ductility of a metal foil composite is maintainable also at comparatively high temperature (for example, 40 to 215 degreeC) below Tg of a resin layer. If the ductility of the metal foil composite can be maintained even at a relatively high temperature (for example, 40 ° C. to 215 ° C.) less than Tg of the resin layer, excellent workability is exhibited even in a method such as warm pressing. For the resin layer, the higher the temperature, the better the moldability. In addition, since pressing is performed warmly so as to mark the shape after pressing (so as not to be restored by elastic deformation), a relatively high temperature (for example, 40 ° C.) below the Tg of the resin layer is also used in this respect. It is preferable that the ductility of the metal foil composite can be maintained even at ˜215 ° C.).
When the metal foil composite includes an adhesive layer and a resin layer, or when there are a plurality of resin layers such as a metal foil composite having a three-layer structure, the resin layer having the lowest Tg (glass transition temperature) is used. Tg is adopted.

<Manufacture of copper foil composite>
Ingots were prepared by adding the elements listed in Tables 1 and 2 to electrolytic copper containing 99.99% by mass or more of Cu and the balance consisting of unavoidable impurities, and then hot-rolled to remove oxides by surface cutting. After that, cold rolling, annealing and pickling are repeated until the thickness t ₂ (mm) shown in Tables 1 and 2 is reduced. Finally, annealing is performed to ensure workability, and rust prevention treatment is performed with benzotriazole. A metal foil was obtained. The tension during cold rolling and the rolling condition in the width direction of the rolled material were made uniform so that the metal foil had a uniform structure in the width direction. In the next annealing, temperature control was performed using a plurality of heaters so as to obtain a uniform temperature distribution in the width direction, and the copper temperature was measured and controlled.
Furthermore, after performing the surface treatment shown in Table 1 and Table 2 on the obtained copper foil surface, in order to control the crystal grain size of the copper foil, it was heated at 100 ° C. for 2 hours, and then in Table 1 and Table 2. Using the resin film shown (resin layer), the resin film was laminated by vacuum pressing (pressing pressure 200 N / cm ² ) at a temperature equal to or higher than (Tg of resin layer + 50 ° C.), and the metal foil having the layer structure shown in Tables 1 and 2 A composite was prepared. However, in Examples 25 and 26 and Comparative Examples 2 and 4, the resin film was laminated in the same manner without heating after the surface treatment. Moreover, after performing the said surface treatment about Examples 27-29, about Example 27, copper foil was heated at 75 degreeC for 30 minutes, and about Example 28, copper foil was heated at 150 degreeC for 30 minutes, and implemented. For Example 29, the copper foil was heated at 350 ° C. for 30 minutes. And the resin film was laminated | stacked similarly similarly after that.
Recrystallization of copper foil occurs during the above vacuum press, but by heating it at 100 ° C. for 2 hours in advance, isotropic recrystallized grains can be obtained as shown in Table 3 to be described later. did it. Note that when laminating the resin film on both surfaces of a copper foil, according to measure both sides of f _1, who f ₁ is smaller the surface treatment of the copper foil surface of the (better adhesive strength is weak) in Table 1, Table 2 did.
In Tables 1 and 2, Cu represents a metal foil, PI represents a polyimide film, and PET represents a polyethylene terephthalate film. The Tg of PI and PET were 220 ° C and 70 ° C, respectively.

The surface treatment conditions are as follows.
Chromate treatment: Electrolytic treatment was performed at a current density of 1 to 10 A / dm ² using a chromate bath (K ₂ Cr ₂ O ₇ : 0.5 to 5 g / L).
Ni coating + chromate treatment: Ni plating bath (Ni ion concentration: 1-30 g / L Watt bath) was used, and Ni plating was performed at a plating solution temperature of 25-60 ° C. and a current density of 0.5-10 A / dm ² . Thereafter, chromate treatment was performed in the same manner as described above.
Roughening treatment: electrolytic treatment using treatment liquid (Cu: 10-25 g / L, H2SO4: 20-100 g / L), temperature 20-40 ° C, current density 30-70 A / dm ² , electrolysis time 1-5 seconds Went. Then, using Ni-Co plating solution (Co ion concentration: 5-20 g / L, Ni ion concentration: 5-20 g / L, pH: 1.0-4.0), temperature 25-60 ° C., current density: was Ni-Co plating 0.5~10A / dm ^2.

<Manufacture of aluminum foil composite>
The Al foil was 25 μm by cold rolling based on a commercially available pure aluminum plate 0.1 mm. This raw foil is degreased and washed with a 5% NaOH solution, and then the resin film (resin layer) shown in Table 4 is used to laminate the resin film by vacuum pressing (pressing pressure 200 N / cm ² ) at 350 degrees. A metal foil composite having a layer structure shown in 4 was produced.

<Manufacture of Ni foil composite>
A Ni ingot having a purity of 99.90% by mass or more was cast, and Ni foil (thickness: 17 μm) according to JIS H4551 NW2200Ni was produced by repeating hot rolling, cold rolling and annealing. In order to improve the adhesion, the Ni foil was annealed at 700 ° C for 30 minutes, then pickled in sulfuric acid and washed with alkali, then Ni plating sulfamic acid (current density 10A / dm2, plating thickness 1μm) gave. Thereafter, the resin film (resin layer) shown in Table 4 was used, and the resin film was laminated at 350 ° C. by vacuum press (pressing pressure 200 N / cm ² ) to produce a metal foil composite having a layer structure shown in Table 4.

<Manufacture of stainless steel foil composite>
Each commercially available SUS301, SUS304, SUS316, SUS430, SUS631 stainless steel plate was annealed and softened, and then cold-rolled to a thickness of 25 μm. Thereafter, the surface was thinned to 18 μm while roughening the surface by buffing No. 400, and then the surface was cleaned with ultrasonic waves. Thereafter, the film was annealed at 1000 ° C. for 5 seconds in an argon atmosphere. The resin film (resin layer) shown in Table 4 was used, and the resin film was laminated at 350 ° C. by vacuum pressing (pressing pressure 200 N / cm ² ). A metal foil composite having the layer structure shown in FIG.

<Manufacture of mild steel foil composite>
A commercially available JIS G3141 SPCCA mild steel sheet was cold-rolled to a thickness of 25 μm by repeating cold rolling and annealing. Thereafter, the surface was thinned to 18 μm while roughening the surface by buffing No. 400, and then the surface was cleaned with ultrasonic waves. Thereafter, the film was annealed at 1000 ° C. for 5 seconds in an argon atmosphere. The resin film (resin layer) shown in Table 4 was used, and the resin film was laminated at 350 ° C. by vacuum pressing (pressing pressure 200 N / cm ² ). A metal foil composite having the layer structure shown in FIG.

<Production of Fe-Ni alloy foil composite>
Repeated casting, hot rolling, chamfering, cold rolling, and annealing by vacuum melting to have a composition of Fe-36 mass% Ni, Fe-50 mass% Ni, and Fe-85 mass% Ni, respectively, to a thickness of 25 μm Cold rolled. Thereafter, the surface was thinned to 18 μm while roughening the surface by buffing No. 400, and then the surface was cleaned with ultrasonic waves. Thereafter, the film was annealed at 1000 ° C. for 5 seconds in an argon atmosphere. The resin film (resin layer) shown in Table 4 was used, and the resin film was laminated at 350 ° C. by vacuum pressing (pressing pressure 200 N / cm ² ). A metal foil composite having the layer structure shown in FIG.

<Manufacture of western white foil composite>
An ingot was cast so as to have the components described in JIS H3110 C7451, and hot rolling, cold rolling, and annealing were repeated to obtain a white foil with a thickness of 25 μm. Thereafter, after recrystallization annealing at 800 ° C. for 10 seconds in an argon atmosphere, pickling with a sulfuric acid solution and alkali cleaning were performed, followed by Ni-sulfamate plating (current density 10 A / dm 2, plating thickness 1 μm). Thereafter, the resin film (resin layer) shown in Table 4 was used, and the resin film was laminated at 350 ° C. by vacuum press (pressing pressure 200 N / cm ² ) to produce a metal foil composite having a layer structure shown in Table 4.
In Table 4, Al, Ni, SUS, and white and white indicate metal foils, and PI indicates a polyimide film. The Tg of PI was 220 ° C.

<Tensile test>
A plurality of strip-shaped tensile test pieces having a width of 12.7 mm were produced from each metal foil composite. About the tensile test of metal foil and a resin film, the metal foil simple substance before lamination | stacking and the resin film simple substance were made into 12.7 mm strip shape.
Then, a tensile test was performed in a direction parallel to the rolling direction of the metal foil according to JIS-Z2241 using a tensile tester. Tables 1 and 2 show the test temperatures during the tensile test.
<180 ° peel test>
Performing 180 ° peel test to measure the 180 ° peel adhesive strength f _1. First, a plurality of strip-shaped peel test pieces having a width of 12.7 mm were produced from the metal foil composite. The metal foil surface of the test piece was fixed to the SUS plate, and the resin layer was peeled off in the 180 ° direction. For Examples in which the resin layer was present on both sides of the metal foil, the resin layer + metal foil was fixed to the SUS plate, and the opposite resin layer was peeled off in the 180 ° direction. In Examples in which the metal foil was present on both surfaces of the resin layer, the metal foil on one side was removed, the opposite metal foil side was fixed to the SUS plate, and the resin layer was peeled off in the 180 ° direction. Other conditions were in accordance with JIS-C5016.
In the JIS standard, the metal foil layer is peeled off, but the resin layer was peeled off in the examples in order to reduce the influence of the thickness and rigidity of the metal foil.

<Evaluation of isotropic crystal grains of copper foil>
In order to evaluate the isotropy of the crystal grains of the copper foil, (the average value of the diameters of the maximum inscribed circles of the crystal grains of the copper foil observed from the plane orientation) / (the crystal grains of the copper foil observed from the plane orientation) Value (ratio) R represented by (the average value of the diameters of the minimum circumscribed circle). Specifically, an area of 0.1 × 0.1 mm on the surface of the copper foil was measured by EBSD using an electron microscope (manufactured by JEOL Ltd .: JEOL JXA-8500F), and a portion having an angle difference of 5 ° or more was observed at the grain boundary. The crystal grain size was measured as (excluding twin grain boundaries), and the average crystal grain size was determined. Except where the crystal grain size is less than 10 μm, the maximum inscribed circle and the minimum circumscribed circle were obtained for 150 randomly extracted crystal grains, and the average value of each was calculated. The EBSD measurement was performed using an OIM (crystal orientation analyzer) manufactured by TSL Solutions.

<Evaluation of workability>
Workability was evaluated using the cup test apparatus 10 shown in FIG. The cup test apparatus 10 includes a pedestal 4 and a punch 2, and the pedestal 4 has a truncated cone-shaped slope, and the truncated cone is tapered from the top to the bottom. Is at 60 ° from the horizontal plane. A circular hole having a diameter of 15 mm and a depth of 7 mm communicates with the lower side of the truncated cone. On the other hand, the punch 2 has a hemispherical cylinder with a diameter of 14 mm at the tip, and the hemisphere at the tip of the punch 2 can be inserted into the circular hole of the truncated cone.
Note that the connecting portion between the tapered tip of the truncated cone and the lower circular hole of the truncated cone is rounded with a radius (r) = 3 mm.

Then, the metal foil composite is punched into a disk-shaped test piece 20 having a diameter of 30 mm, the metal foil composite is placed on the inclined surface of the truncated cone of the pedestal 4, and the punch 2 is pushed down from above the test piece 20 to make the pedestal 4. Was inserted into the circular hole. Thereby, the test piece 20 was shape | molded in the conical cup shape.
In addition, when there is a resin layer only on one side of the metal foil composite, it is placed on the base 4 with the resin layer facing up. When there are resin layers on both sides of the metal foil composite, the resin layer bonded to the M surface is placed on the base 4 with the resin layer facing up. When both surfaces of the metal foil composite are Cu, either may be the top.
The presence or absence of cracking of the metal foil in the test piece 20 after molding was visually determined, and the workability was evaluated according to the following criteria.
A: The metal foil was not cracked and the metal foil was not wrinkled. ○: The metal foil was not cracked, but the metal foil was slightly wrinkled. X: The metal foil was cracked.

The obtained results are shown in Tables 1 to 4. Incidentally, Table 1, test temperature shown in Table 4, show _{F, f 1, f 2,} f 3, and the temperature were evaluated in the processability.

As is clear from Tables 1 to 4, in each example, both (f ₃ × t ₃ ) / (f ₂ × t ₂ ) ≧ 1 and 1 ≦ 33f ₁ / (F × T) are satisfied, Excellent workability.
In addition, when Example 13 and Example 23 using the metal foil laminated body of the same structure are compared, the direction of Example 13 which measured F etc. by performing the tensile test at room temperature (about 25 degreeC) is Example. 23, the value of (f ₃ × t ₃ ) / (f ₂ × t ₂ ) is larger. In Example 23, it can be seen that the resin layer is weak (f ₃ is small) due to the increase in test temperature.
In addition, as shown in Table 3, when copper foil was used as the metal foil, Examples 1 to 24 in which the resin films were laminated after heating at 100 ° C. for 2 hours were laminated without heating. As compared with Examples 25 and 26, the R value was high, and isotropic recrystallized grains could be obtained. In addition, when a resin film is laminated | stacked after heating copper foil below 80 degreeC (Example 27, heating 75 degreeC) or 150-350 degreeC (Example 28, 150 degreeC, Example 29, 350 degreeC), R value However, the effect of heating the copper foil did not occur.

On the other hand, in Comparative Example 1 in which the resin film is laminated without the surface treatment to the copper foil, the adhesion strength is lowered, the value of 33f ₁ / (F × T) is less than 1, the workability is deteriorated.
In Comparative Examples 2 and 5 in which the pressing pressure during lamination was reduced to 100 N / cm ² , the adhesive strength was lowered, the value of 33f ₁ / (F × T) was less than 1, and workability was deteriorated.
In Comparative Examples 3, 6, and 10 in which the thickness of the resin film was reduced, the strength of the resin film was weaker than that of the metal foil, and the value of (f ₃ × t ₃ ) / (f ₂ × t ₂ ) was less than 1. As a result, workability deteriorated.
In the case of Comparative Example 4 in which the resin film and the metal foil were laminated with an adhesive without being thermally fused, the adhesive strength was lowered, the value of 33f ₁ / (F × T) was less than 1, and workability was deteriorated.
In the case of Comparative Example 7 in which the Sn content in the copper foil exceeded 500 ppm, the crystal grains were more easily refined during recrystallization, and f ₂ increased due to the increase in strength due to alloying, and (f ₃ × t ₃ ) / (f ₂ × t ₂ ) and 33f ₁ / (F × T) were less than 1, and workability deteriorated.
In the case of Comparative Example 8 in which the composite was produced under the same conditions as in Example 22 except that the content of Ag in the copper foil was less than 50 ppm, the effect of coarsening the crystal grains due to Ag did not occur, and the crystal grains were since smaller than example 22, F, _{f 2,} is _{increased, (f 3 × t 3)} / (f 2 × t 2), 33f 1 / (F × T) is less than 1, workability was deteriorated .
Although the metal foil laminates having the same configurations as those in Examples 30, 31, and 33 were used, the adhesive strength was also lowered in Comparative Examples 9, 11, and 12 in which the press pressure during lamination was reduced to 100 N / cm ² . The value of 33f ₁ / (F × T) was less than 1, and the workability deteriorated.

Claims (5)

A copper foil having a thickness of 50 μm or less, a fracture strain of 4% or more, and containing one or more selected from the group of Ag, Sn, In, Au, Mn, Ni, and Zn in a mass ratio of 30 ppm to 500 ppm in total. In the crystal grain having an average crystal grain size of 10 μm or more and further exceeding 10 μm, the average diameter of the maximum inscribed circle of the copper foil crystal grain observed from the surface of the copper foil) / (The average value of the diameter of the minimum circumscribed circle of the crystal grains of the copper foil observed from the surface of the copper foil) The copper foil satisfying 0.5 ≦ R ≦ 0.8 and the resin layer having a thickness of 120 μm or less And a metal foil composite laminated with
The thickness of the copper foil is t ₂ (mm), the stress of the copper foil at a tensile strain of 4% is f ₂ (MPa), the thickness of the resin layer is t ₃ (mm), and the thickness of the resin layer is 4% of the tensile strain. When the stress is f ₃ (MPa), Formula 1: (f ₃ × t ₃ ) / (f ₂ × t ₂ ) ≧ 1 is satisfied,
In addition, the 180 ° peel strength between the copper foil and the resin layer is f ₁ (N / mm), the strength at 30% tensile strain of the metal foil composite is F (MPa), and the thickness of the metal foil composite is A metal foil composite characterized by satisfying the formula 2: 1 ≦ 33f ₁ / (F × T) where T is (mm).   The metal foil composite according to claim 1, wherein the formula 1 and the formula 2 are satisfied at a temperature lower than the glass transition temperature of the resin layer.   3. The metal foil composite according to claim 1, wherein the ratio 1 / L of the tensile breaking strain 1 of the metal foil composite to the tensile breaking strain L of the resin layer alone is 0.7-1. body.   The molded object formed by processing the metal foil composite in any one of Claims 1-3.   The manufacturing method of the molded object which processes the metal foil composite in any one of Claims 1-3.

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