JP2023162859A - aluminum laminate - Google Patents

Abstract

To provide a metal laminate which has excellent electromagnetic shield characteristics and bending characteristics against repeated bending.SOLUTION: There is provided an aluminum laminate for an electromagnetic shield tape in which at least a resin film and an aluminum foil are stacked, wherein a thickness t1 of the aluminum foil is 40% or more and 60% or less with respect to a thickness t0 of the aluminum laminate, 0.2% bearing force in a roll processing direction of the aluminum laminate is larger than 50.0 N/mm2, breaking elongation in the roll processing direction of the aluminum laminate is 30.0% or more, and a width distortion ratio in a roll processing width direction of the aluminum laminate is 0.60 or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to an aluminum laminate with excellent flexibility.

With the recent development of information and communication technology, devices that generate electromagnetic waves are being used in various fields. For example, with the development of AI technology, the installation and control of various sensors have come into widespread use, as exemplified by the operation of equipment by robots and autonomous driving in the automobile field.

On the other hand, the generation of electromagnetic waves that become noise is increasing, for example, in electric vehicles driven by AC motors as a power source. For this reason, it is important to prevent various control devices, sensors, and cables that connect them from malfunctioning due to exposure to electromagnetic waves, and there is a need to provide electromagnetic shielding to various electric cables as well.

For example, as a means for applying electromagnetic shielding to electric wire cables, electromagnetic shielding materials described in JP2019-176022A (Patent Document 1) and JP2013-065675A (Patent Document 2) are known. ing.

The electromagnetic wave shielding material as described in Patent Document 1 is used to provide electromagnetic shielding by wrapping it around electric wires, cables, etc., but in order to exhibit high electromagnetic shielding properties, a layer made of metal foil such as copper foil or aluminum foil is used. as all or part of the structure. However, although the electromagnetic shielding material described in Patent Document 1 has excellent electromagnetic shielding properties, it has a problem in that it is poor in flexibility, especially against repeated bending, and is not easy to use.

On the other hand, the electromagnetic shielding material described in Cited Document 2 is a sheet-shaped electromagnetic shielding material applied to a flat cable, but since it does not include a layer of metal foil, it has poor flexibility against repeated bending. Although it is excellent, there is a problem in that it does not provide a high degree of electromagnetic shielding.

Furthermore, in recent years, as mentioned above, sensors and control devices have been attached to devices in various fields, so the wires and cables that connect them are often used at the joints of the arms of robots, for example, and for devices used in vehicles. It is increasingly being used for movable parts that are subject to severe repeated bending, such as door mirrors and door opening/closing parts.

For this reason, electromagnetic wave shielding materials applied to electric wires and cables are required to have higher bending characteristics than ever before that can withstand repeated bending. However, in order to improve the flexibility of electromagnetic shielding materials against repeated bending as described above, it is necessary to make the electromagnetic shielding layer thinner or rougher by using a vapor-deposited metal layer or a resin layer containing conductive particles. On the other hand, if you try to secure excellent electromagnetic shielding properties by using metal foil for the electromagnetic shielding layer, it will require a high degree of resistance to repeated bending. There was an essential problem that flexibility could not be obtained.

JP 2019-176022 Publication Japanese Patent Application Publication No. 2013-065675

Therefore, the present invention is a metal laminate for use in electromagnetic shielding tape, which is lightweight, has excellent electromagnetic shielding properties, and includes metal foil that can be wrapped around a cable, and which also exhibits excellent bending properties against repeated bending. The purpose is to provide

The present inventors have conducted extensive studies on materials exhibiting advanced electromagnetic shielding characteristics, materials exhibiting advanced bending characteristics against repeated bending, and combinations of these materials. As a result, in a laminate in which a resin film is laminated to an aluminum foil as the main material of the electromagnetic shielding material, the thickness ratio of the aluminum foil in the laminate is within a specific range, and the roll processing direction of the laminate is The present inventors have discovered that when the 0.2% yield strength, elongation at break, and width strain ratio of the material are higher than specific values, the bending properties against repeated bending are significantly improved, and the present invention has been completed.

That is, according to the present invention, in an aluminum laminate in which at least a resin film and an aluminum foil are laminated, the thickness _t1 of the aluminum foil is 40% or more and 60% or less of the thickness _t0 of the aluminum laminate, The aluminum laminate has a 0.2% proof stress in the rolling direction of greater than 50.0 N/mm ² , an elongation at break in the rolling direction of the aluminum laminate of 30.0% or more, and Provided is an aluminum laminate for electromagnetic shielding tape, characterized in that the width strain ratio in the width direction is 0.60 or more.

The aluminum laminate of the present invention has a basic configuration in which at least one layer of resin film is laminated onto aluminum foil. In addition, in the present invention, the ratio of the thickness t ₁ of the aluminum foil to the thickness t ₀ of the aluminum laminate and the 0.2% proof stress in the rolling direction of the aluminum laminate are limited because these values are as described above. If it is outside this range, when the aluminum laminate is bent or repeatedly bent, some of the aluminum foil in the laminate will not be able to withstand the deformation, resulting in premature breakage and poor electromagnetic shielding properties. This is because you will not be able to obtain it. Therefore, the aluminum laminate of the present invention achieves two contradictory properties: maintaining high electromagnetic shielding properties and achieving high bending properties against repeated bending.

In the aluminum laminate of the present invention, the aluminum foil has a total diffraction intensity I that is the sum of the diffraction intensities showing each of the (111) plane, (200) plane, (220) plane, and (311) plane in X-ray diffraction. The ratio P 200 of the diffraction intensity I ₂₀₀ indicating the (200) plane to ₀ is 30% or more and 60% _or less, and the ratio P ₂₂₀ of the diffraction intensity _{I 220} indicating the (220) plane to the total diffraction intensity I 0 is 10%. It is preferable that it is 40% or less.

By limiting the ratio P 220 of the diffraction intensity I ₂₀₀ indicating the ( ₂₀₀ ) plane of the aluminum foil to the ratio P 220 of the diffraction intensity I ₂₂₀ indicating the ( ₂₂₀ ) plane within the above range, excellent bending properties against repeated bending can be achieved. can be applied to the aluminum laminate.

In the aluminum laminate of the present invention, the aluminum foil preferably contains 0.4% by mass or more and 1.7% by mass or less of iron.

When the iron content in the aluminum foil is less than 0.4% by mass, it becomes difficult to refine the crystal grains in the aluminum foil, resulting in insufficient strength of the aluminum foil and pinholes after cold rolling. The number of cases where this occurs will also increase. On the other hand, if the iron content is more than 1.7% by mass, coarse intermetallic compounds are likely to occur, resulting in poor workability and also in this case, pinholes are likely to occur.

In the aluminum laminate of the present invention, the thickness of the aluminum foil in each layer is preferably 5 μm or more and 300 μm or less, more preferably 5 μm or more and 150 μm or less, and still more preferably 6 μm or more and 80 μm or less.

When the thickness of the aluminum foil is within the above range, the aluminum laminate of the present invention can be easily wrapped around something with an extremely small radius of curvature, such as a cable, without causing breakage. To enable molding of an electromagnetic shielded cable without impairing its flexibility against repeated bending.

In the aluminum laminate of the present invention, the resin film and the aluminum foil are laminated via an adhesive, and the peel strength between the resin film and the aluminum foil is preferably 3.0 N/15 mm or more.

If the peel strength between the resin film and the aluminum foil is less than 3.0N/15mm, when subjected to bending deformation due to repeated bending, the deformation of the aluminum foil will not be able to sufficiently follow the deformation of the resin film, causing local damage. This is because the aluminum foil itself may deform excessively and break.

In the present invention, the resin film suitable for effectively improving the bending properties while maintaining the electromagnetic shielding effect of the aluminum foil preferably contains at least a polyester resin such as a polyethylene terephthalate resin. .

Further, the aluminum laminate of the present invention may further have a printed layer or a coating layer laminated thereon from the viewpoint of improving convenience and decorativeness.

In the aluminum laminate of the present invention, aluminum foil is laminated with a resin film, and the thickness _t1 of the aluminum foil is set to 40% or more and 60% or less with respect to the thickness _t0 of the aluminum laminate. The 0.2% yield strength is greater than 50.0 N/mm ² , the elongation at break in the roll processing direction of the aluminum laminate is 30.0% or more, and the width strain ratio of the aluminum laminate in the roll processing width direction is 0.2%. By making it 60 or more, extremely excellent bending characteristics against repeated bending can be achieved while maintaining high electromagnetic shielding characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing a layered structure of an aluminum layered product according to a first embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing the laminated structure of an aluminum laminate according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing the laminated structure of an aluminum laminate according to a third embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing the laminated structure of an aluminum laminate according to a fourth embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing the laminated structure of an aluminum laminate according to a fifth embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing the laminated structure of an aluminum laminate according to a sixth embodiment of the present invention.

Hereinafter, an aluminum laminate according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and various changes can be made without departing from the technical idea of the present invention.

<Basic composition of aluminum laminate>
FIG. 1 shows an aluminum laminate in which one resin film (layer) 3 is laminated to one aluminum foil (layer) 2 via an adhesive (layer) 4, as a first embodiment of the present invention. A cross-sectional view of 1a is shown.

In the aluminum laminate 1a of this embodiment, at least a resin film (layer) 3 and an aluminum foil (layer) 2 are laminated, as shown in FIG. If the aluminum foil (layer) 2 is alone, the bending properties against repeated bending will be significantly reduced. Therefore, by laminating the aluminum foil (layer) 2 and at least one resin film (layer) 3, the bending properties can be improved. The decline is suppressed or improved.

Moreover, it is preferable that the aluminum laminate 1a further has an adhesive (layer) 4 between the aluminum foil (layer) 2 and the resin film (layer) 3. In this embodiment, since the aluminum foil (layer) 2 and the resin film (layer) 3 are firmly adhered via the adhesive (layer) 4, the electromagnetic wave shield that covers electric wire cables etc. with an extremely small radius of curvature can be used. It can be used more suitably as a material. Note that the aluminum foil (layer) 2 and the resin film (layer) 3 of this embodiment do not necessarily have to be laminated with the adhesive (layer) 4 interposed therebetween; for example, the aluminum foil (layer) ) 2 and the resin film (layer) 3 may be directly laminated.

FIG. 2 shows, as a second embodiment, a cross-sectional view of an aluminum laminate 1b in which a printed layer 5 or a coating layer 5 is laminated on the aluminum foil (layer) 2 of the laminate 1a of the first embodiment. 3, as a third embodiment, an aluminum film in which a printed layer 5 or a coating layer 5 is laminated on the resin film (layer) 3 of the laminate 1a of the first embodiment is shown. A cross-sectional view of the laminate 1c is shown. Further, in FIG. 4, as a fourth embodiment, a second resin film (layer) is further placed on the aluminum foil (layer) 2 of the laminate 1a of the first embodiment via an adhesive (layer) 4. ) 3 is shown.

In the present invention, like the aluminum laminates 1b and 1c of the second and third embodiments, the aluminum laminate 1a of the first embodiment is used as the basic structure, and the aluminum foil (layer) 2 or a resin film is A printed layer 5 or a coating layer 5 may be further laminated on (layer) 3. Although not shown, the printing layer 5 or the coating layer 5 is laminated on both sides of the aluminum foil (layer) 2 and the resin film (layer) 3 of the laminate 1a of the first embodiment. Good too.

In the present invention, like the aluminum laminate 1d of the fourth embodiment, the aluminum laminate 1a of the first embodiment is used as a basic structure, and an adhesive (layer) 4 is further applied on the aluminum foil (layer) 2. The second resin film (layer) 3 may be laminated via. In other words, the aluminum laminate 1d of the fourth embodiment has a resin film (layer) 3 on each of one side and the other side of the aluminum foil (layer) 2. Note that in the second to fourth embodiments, the aluminum foil (layer) 2 and the resin film (layer) 3 do not necessarily need to be laminated via the adhesive (layer) 4, as in the first embodiment. It is similar to

In FIG. 5, as a fifth embodiment, a second aluminum foil (layer) is further placed on the resin film (layer) 3 of the laminate 1a of the first embodiment via an adhesive (layer) 4. 6 is a cross-sectional view of an aluminum laminate 1e in which 2 aluminum foils (layers) 2 are laminated, and FIG. A cross-sectional view of an aluminum laminate 1f in which a second resin film (layer) 3 is further laminated on one surface via an adhesive (layer) 4 is shown.

In the present invention, like the aluminum laminate 1e of the fifth embodiment, the aluminum laminate 1a of the first embodiment is used as a basic structure, and an adhesive (layer) 4 is further applied on the resin film (layer) 3. The second aluminum foil (layer) 2 may be laminated via the aluminum foil (layer) 2. In other words, in the aluminum laminate 1e of the fifth embodiment, not only the aluminum foil (layer) 2 is laminated on one side of the resin film (layer) 3, but also the aluminum foil (layer) 2 is laminated on one side of the resin film (layer) 3. In this embodiment, a second aluminum foil (layer) 2 is further laminated on the other side of the resin film (layer) 3 that is not laminated.

In the present invention, the aluminum laminate 1a of the first embodiment is used as a basic structure like the aluminum laminate 1f of the sixth embodiment, and further, other first The aluminum laminate 1a of the embodiment may be repeatedly laminated. Note that in the fifth and sixth embodiments, the aluminum foil (layer) 2 and the resin film (layer) 3 do not necessarily have to be laminated with the adhesive (layer) 4 in between. This is similar to the embodiment.

<0.2% proof stress of aluminum laminate in rolling direction>
The aluminum laminates 1a to 1f of this embodiment have a characteristic that the 0.2% proof stress in the rolling direction is greater than 50.0 N/mm ² . If the 0.2% yield strength in the roll processing direction is 50.0 N/mm2 ^or less, the aluminum laminates 1a to 1f will break early when subjected to repeated bending, resulting in good electromagnetic shielding properties. I won't be able to do it.

Although the detailed mechanism is not clear, it is inferred as follows. For example, the aluminum laminates 1a to 1f of this embodiment, which are formed into a tape shape, are usually coated by being deformed to form a U-shape to an O-shape (instead of being wound spirally). Therefore, when a cable or the like is repeatedly bent, it is alternately subjected to compressive stress generated on the side with a smaller radius of curvature and tensile stress generated on the side with a larger radius of curvature. On the other hand, since the aluminum laminates 1a to 1f of this embodiment are composite materials made of a metal material and a resin material, when the above-mentioned bending is repeated, the resin film (layer) 3 basically breaks down in the laminate. Although the aluminum foil (layer) 2 undergoes repeated elastic deformation, it is considered that the aluminum foil (layer) 2 repeatedly undergoes plastic deformation beyond its elastic limit from an early stage.

Then, if the 0.2% proof stress in the roll processing direction of the aluminum laminates 1a to 1f is small, the aluminum foil (layer) 2 in the aluminum laminates 1a to 1f easily changes from elastic deformation to plastic deformation, resulting in plastic deformation. It is thought that the ratio of bending in the area becomes high, causing so-called metal fatigue and easily breaking.

In addition, in the present invention, the "roll processing direction" means the processing direction when laminating a resin film onto an aluminum foil by a roll-to-roll method. In this embodiment, unless otherwise specified, the aluminum laminates 1a to 1f are made of a resin material used in the rolling direction of the aluminum foil 2 during rolling and when forming the resin film 3 in order to improve the mechanical strength in the longitudinal direction. The layers are stacked so that the direction in which the particles flow coincides with the roll processing direction.

<Thickness ratio of aluminum foil (layer) in aluminum laminate>
The aluminum laminates 1a to 1f of this embodiment are characterized in that the thickness t ₁ of the aluminum foil (layer) 2 is 40% or more and 60% or less of the thickness t ₀ of the aluminum laminate. When the ratio of the thickness t1 of the aluminum foil (layer) ₂ becomes smaller than 40%, not only the cross-sectional area (section modulus) of the aluminum foil (layer) 2 in the aluminum laminate becomes insufficient, but also the aluminum foil (layer) 2 suffers from bending deformation. At this time, the aluminum foil (layer) 2 that is off the neutral plane of the aluminum laminates 1a to 1f will undergo large deformation, so within the large deformation allowed by the resin film (layer) 3, the aluminum foil Layer 2 reaches the breaking strength first and breaks, and as a result, it becomes impossible to obtain good electromagnetic shielding properties.

On the other hand, if the ratio of the thickness t ₁ of the aluminum foil (layer) 2 is larger than 60%, the thickness of the aluminum foil (layer) 2 that occupies the aluminum laminate becomes excessive, so that the aluminum laminates 1a to 1f are bent. When bent, the inside of the aluminum foil (layer) 2 has a surface that receives compressive stress on the side with a small radius of curvature and a surface that receives tensile stress on the side with a large radius of curvature. The foil (layer) 2 undergoes metal fatigue at an early stage and easily breaks even under small stress and small deformation (strain), making it impossible to obtain good electromagnetic shielding properties.

<Elongation at break in the rolling direction of aluminum laminate>
The aluminum laminates 1a to 1f of this embodiment have a characteristic that the elongation at break in a tensile test in the rolling direction is 30.0% or more. If the elongation at break in the rolling direction is less than 30.0%, the aluminum laminates 1a to 1f will break early when subjected to repeated bending, making it impossible to obtain good electromagnetic shielding properties. Therefore, the elongation at break of the aluminum laminates 1a to 1f is preferably 30.0% or more, more preferably 35.0% or more, and even more preferably 40.0% or more. When the elongation at break of the aluminum laminates 1a to 1f is within the above range, it becomes more difficult to break.

<Width strain ratio in the roll processing width direction of aluminum laminate>
The aluminum laminates 1a to 1f of this embodiment have a characteristic that the width strain ratio r in the roll width direction is 0.60 or more. The width strain ratio r in the roll processing width direction is defined as: W ₀ is the width of the aluminum laminate before tensile deformation, W is the width of the aluminum laminate after tensile deformation, L ₀ is the length of the aluminum laminate before tensile deformation, When the length of the aluminum laminate after tensile deformation is L, it is calculated by the following equation (1), and is an index representing the anisotropy when tensile deformation is applied to the material.
r=log(W ₀ /W)/log[(W×L)/(W ₀ ×L ₀ )]...(1)
r: Width strain ratio W ₀ (mm): Width before tensile deformation, W (mm): Width after tensile deformation L ₀ (mm): Length before tensile deformation, L (mm): Length after tensile deformation difference

If the width strain ratio in the roll width direction of the aluminum laminates 1a to 1f is less than 0.60, repeated bending will cause many pinholes to form in the aluminum foil (layer) 2 of the aluminum laminates 1a to 1f at an early stage. , it becomes impossible to obtain good electromagnetic shielding properties.

Although the detailed mechanism is not clear, it is inferred as follows. As described above, when bending is repeated, the aluminum laminates 1a to 1f are alternately subjected to tensile and compressive deformation in the rolling direction. In other words, the deformation of the aluminum laminates 1a to 1f due to this force is divided into deformation in the thickness direction and width direction, but if the width strain ratio is high, that is, it is easy to deform in the width direction, the pins of the aluminum foil (layer) 2 It is thought that deformation becomes easier while suppressing the generation of holes, and good electromagnetic shielding properties can be obtained.

<Characteristics of aluminum foil (diffraction intensity ratio)>
In the aluminum laminates 1a to 1f of this embodiment, the aluminum foil 2 has a total diffraction intensity of (111) plane, (200) plane, (220) plane, and (311) plane in X-ray diffraction. The ratio P ₂₀₀ of the diffraction intensity I ₂₀₀ indicating the ( ₂₀₀ ) plane to a certain total diffraction intensity I ₀ is 30% or more and 60% or less, and the ratio of the diffraction intensity I ₂₂₀ indicating the (220) plane to the total diffraction intensity I 0 It is preferable that _P220 is 10% or more and 40% or less.

By setting the ratio P 220 of the diffraction intensity I ₂₀₀ indicating the (200) plane of the aluminum foil 2 to the ratio P ₂₂₀ of the diffraction intensity I ₂₂₀ indicating the ( ₂₂₀ ) plane within the above range, excellent bending characteristics against repeated bending can be achieved. can be applied to the aluminum laminates 1a to 1f.

The ratio P 200 of the diffraction intensity I ₂₀₀ indicating the (200) plane in X-ray diffraction is the ratio P ₂₀₀ of the (111) plane, (200) plane, (220) plane and (311) plane on the diffraction chart in the X-ray diffraction apparatus. Each diffraction intensity indicating each is measured as an integrated intensity after removing the background (BG), and the ratio P ₂₀₀ to the total diffraction intensity I ₀ , which is the sum of the above respective diffraction intensities, is calculated by the following (Formula 2). be done. The actual integrated intensity is measured by reading it using an integrated intensity calculation program that is analysis software of the X-ray diffraction apparatus used.
P ₂₀₀ = [{(200) plane diffraction intensity I ₂₀₀ }/{(111) plane, (200) plane, (220) plane, and (311) plane diffraction intensity I ₀ }]×100[ %]...(Formula 2)

The ratio P ₂₂₀ of the diffraction intensity I ₂₂₀ indicating the (220) plane in X-ray diffraction can also be determined in the same manner. That is, the numerator in (Formula 2) may be replaced with "diffraction intensity I ₂₂₀ of the (220) plane". Note that the surface on which the X-ray diffraction intensity is measured is the rolled surface of the aluminum foil 2, that is, the surface that comes into contact with the rolling roll during cold rolling when manufacturing the aluminum foil 2, and is the surface of the aluminum foil 2 of the aluminum laminates 1a to 1f. It is also the surface of (layer) 2.

In the diffraction intensity detected by X-ray diffraction, the present inventors set the ratio _{P 200 of} the diffraction intensity I ₂₀₀ indicating the (200) plane to the above-mentioned total diffraction intensity I 0 from 30% to 60%. , and the ratio P ₂₂₀ of the diffraction intensity I ₂₂₀ representing the (220) plane is set to 10% or more and 40% or less, it has been found that excellent bending properties against repeated bending can be imparted to the aluminum laminates 1a to 1f. The reason for this is that if the ratios P 200 and P ₂₂₀ of the diffraction intensities I ₂₀₀ and I ₂₂₀ indicating the (200) and ( ₂₂₀ ) planes are out of the above range, the balance of each crystal orientation will be lost, resulting in repeated This is thought to be because the bending properties against bending are reduced. From the viewpoint of bending properties against repeated bending, it is more preferable that the ratio P ₂₀₀ of the diffraction intensity I ₂₀₀ indicating the (200) plane to the total diffraction intensity I ₀ which is the sum of each diffraction intensity is 30% or more and 50% or less .

In order to keep the ratios P 200 and P ₂₂₀ of the diffraction intensities I ₂₀₀ and I ₂₂₀ representing the (200) plane and the ( ₂₂₀ ) plane within a predetermined range, there is no particular restriction, but the aluminum foil 2 described later In order to homogenize an ingot having a composition of ℃), and the working conditions for the subsequent plate making process (hot rolling, cold rolling, intermediate annealing) and foil making process (cold rolling) should be set to general conditions. Bye. Further, the obtained aluminum foil may or may not be subjected to final annealing. By laminating the thus produced aluminum foil 2 with a thickness of 5 to 300 μm with at least one layer of resin film 3, it is possible to obtain aluminum laminates 1a to 1f that exhibit excellent flexibility against repeated bending. can.

<Characteristics of aluminum foil (thickness)>
The thickness of the aluminum foil 2 used in this embodiment is preferably 5 μm or more and 300 μm or less, more preferably 5 μm or more and 150 μm or less, and still more preferably 6 μm or more and 80 μm or less.

If the thickness of the aluminum foil 2 is less than 5 μm, there is a risk that it will break during molding or that pinholes will occur or expand. Furthermore, if the thickness of the aluminum foil 2 exceeds 300 μm, not only will it be difficult to obtain an X-ray diffraction intensity within the range specified in this embodiment, but also the weight will increase when formed into aluminum laminates 1a to 1f. , the coverage of cables etc. will be reduced.

Therefore, in this embodiment, by controlling the thickness of the aluminum foil 2 within the above-mentioned range, the aluminum laminates 1a to 1f can break even if they have an extremely small radius of curvature, such as a cable. It can be easily wound without any bending, and it can be formed into an electromagnetic shielded cable without impairing its flexibility against repeated bending.

<Characteristics (composition) of aluminum foil>
The aluminum foil 2 used in this embodiment contains iron (Fe) from 0.4% by mass to 1.7% by mass. The content of Fe in the aluminum foil 2 is more preferably 0.7% by mass or more and 1.7% by mass or less, and even more preferably 1.1% by mass or more and 1.7% by mass or less.

If the Fe content is less than 0.4% by mass, the effect of refining the crystal grains of the aluminum foil 2 will be insufficient, the strength of the foil will decrease, and a relatively large number of pinholes will occur after cold rolling. Tend. On the other hand, if the Fe content exceeds 1.7% by mass, coarse intermetallic compounds tend to occur, which reduces workability (rollability, formability) and also tends to cause pinholes. Become.

Therefore, in this embodiment, by controlling the Fe content to 0.4% by mass or more and 1.7% by mass or less, the crystal grains of the aluminum foil 2 are made finer and the generation of coarse intermetallic compounds is suppressed. At the same time, appropriate strength and elongation of the aluminum foil 2 are ensured.

In the aluminum foil 2 used in this embodiment, the content of silicon (Si) is preferably 0.30% by mass or less, and more preferably 0.15% by mass or less. When the Si content exceeds 0.30% by mass, coarse crystallized substances are likely to occur, the effect of refining the crystal grains of the aluminum foil 2 is reduced, and the strength and workability also tend to decrease. be. Note that since Si is unavoidably present in industrial aluminum, the lower limit of the Si content may be set to 0.01% by mass.

In the aluminum foil 2 used in this embodiment, the content of copper (Cu) is preferably 0.05% by mass or less, more preferably 0.02% by mass or less. If the Cu content exceeds 0.05% by mass, there is a risk that workability and corrosion resistance will decrease. Note that since Cu is unavoidably present in industrial aluminum, the lower limit of the Cu content may be set to 0.001% by mass.

In the aluminum foil 2 used in this embodiment, the remainder other than the composition (elements) mentioned above is aluminum (Al). Here, the aluminum foil 2 may each contain 0.05% by mass or less of trace elements other than the above-mentioned Fe, Si, and Cu. Examples of trace elements include manganese (Mn), magnesium (Mg), zinc (Zn), titanium (Ti), zirconium (Zr), gallium (Ga), chromium (Cr), vanadium (V), and the like. These elements may exist in trace amounts in the aluminum foil 2 as unavoidable impurity elements.

As mentioned above, the composition of the aluminum foil 2 used in this embodiment has been explained, but the composition of the aluminum foil 2 is, for example, alloy number 8021 or 8079 specified in JISH4160-1994, which is commercially available. It is preferable that the composition corresponds to . Therefore, the aluminum foil 2 is a versatile aluminum foil having a composition of 8000 series or close to 8000 series, which does not require expensive additive elements, and has excellent moldability, and when laminated with the resin film 3, This gives the aluminum laminates 1a to 1f excellent flexibility against repeated bending.

<Peel strength of aluminum laminate>
In the aluminum laminates 1a to 1f of this embodiment, the peel strength between the aluminum foil (layer) 2 and the resin film (layer) 3 is It is preferable that the peel strength when peeling the aluminum foil (layer) 2 from the aluminum foil (layer) 2 is 3.0 N/15 mm or more. When the peel strength is less than 3.0 N/15 mm, when repeated bending deformation is applied, the deformation of the aluminum foil (layer) 2 cannot sufficiently follow the deformation of the resin film (layer) 3, causing local damage. This is because the aluminum foil (layer) 2 itself may deform excessively and break.

<Adhesive (layer)>
In the aluminum laminates 1a to 1f of this embodiment, the aluminum foil (layer) 2 and the resin film (layer) 3 may be directly bonded together by heat fusion, for example, but the peel strength (adhesion strength) is improved. In view of this, the aluminum foil (layer) 2 and the resin film (layer) 3 may be bonded together via a reactive adhesive (layer) 4.

When laminating aluminum foil (layer) 2 and resin film (layer) 3 using adhesive (layer) 4, the main agent of the adhesive constituting adhesive (layer) 4 is polyester-based, polyester-urethane-based, etc. It is preferable to use an adhesive such as, for example, and the amount applied is about 0.5 to 10.0 g/m ² . If the coating amount is less than 0.5 g/ ^m2 , there is a risk that the adhesive strength will be insufficient, while if it exceeds 10.0 g/ ^m2 , no further improvement in adhesive strength will be observed, and the moisture resistance and economic efficiency will deteriorate. This is because it is undesirable from a viewpoint as well. Furthermore, aliphatic or aromatic isocyanates can be used as curing agents.

In particular, in the aluminum laminates 1a to 1f of this embodiment, a heat-reactive polyester polyol adhesive consisting of two or more liquids is used, the weight average molecular weight is 30,000 or more, and the softening point after curing of the coating film is 180°C or more. It is preferable to use one that is. Note that the adhesion method is not particularly limited, but it is preferable to use a dry lamination method.

<Resin film (layer)>
The resin film 3 used in this embodiment is not particularly limited, but preferably contains at least a polyester resin. As the polyester resin film, polyethylene terephthalate can be suitably used, but films made of polyethylene naphthalate or polybutylene terephthalate may also be used.

The resin film 3 may be manufactured by any known manufacturing method, such as an inflation method, a casting method, or an extrusion method. For example, a multilayer film made of nylon as a base and coextruded with polyester resin or ethylene vinyl alcohol (EVOH) resin can also be used. Further, in the case of the resin film 3 made of polyethylene terephthalate resin, a film manufactured by general biaxial stretching may be used, and a non-stretched film may be used. The thickness of the resin film 3 is preferably, for example, 10 μm or more and 30 μm or less, and more preferably 12 μm or more and 20 μm or less, considering the flexibility of the aluminum laminates 1a to 1f against repeated bending and ease of handling. preferable. The tensile strength ratio (RD/TD) of the resin film 3 is preferably, for example, 1.15 or more, and more preferably 1.2 or more, considering the width strain due to compressive stress and tensile stress during bending. Further, the resin film 3 may contain additives and impurities. Examples of additives include curing agents, crosslinking agents, antioxidants, ultraviolet absorbers, and lubricants.

<Printing layer, coating layer>
The aluminum laminates 1a to 1f of this embodiment may be further coated or printed for convenience, decoration, and the like. Examples of the coating layer include laminating an insulating layer, an adhesive layer, a waterproof layer, an anti-corrosion layer, and the like. As the printing layer, a known printing ink can be used, and the resin components included include cellulose, polyvinyl butyral, polyamide, polyolefin, polyurethane, acrylic, polyester, polyvinyl chloride, polyvinyl alcohol, ethylene-vinyl acetate, etc. Examples include those containing at least one of polymers, ethylene-vinyl alcohol copolymers, and ethylene-ethyl acrylate copolymers. Furthermore, examples of the coloring component contained in the printing ink include those containing at least one of organic pigments, inorganic pigments, and dyes.

<Form of use>
The aluminum laminates 1a to 1f of this embodiment can be suitably used as electromagnetic shielding materials, particularly electromagnetic shielding tapes for electromagnetic shielding cables. In particular, it is suitable for use in wire harnesses that pass through automobile door mirrors, robot arm joints, etc., which require high flexibility against repeated bending. For example, the cable can be covered by wrapping the aluminum laminates 1a to 1f of this embodiment around the cable to form a cylinder (UO pipe) and joining them.

Examples and comparative examples will be given below to further clarify the characteristics of the present invention.

<Preparation of aluminum foil>
First, aluminum foil samples used in Examples of the present invention and Comparative Examples were prepared as described below. Aluminum foils A to D shown in Table 1 were produced and used as aluminum foil samples for Examples and Comparative Examples. In Table 1, "other elements" indicates the total content of unavoidable impurity elements (B, Bi, Pb, Na, etc.) other than the elements specified by JIS (for example, JIS H4160).

In the manufacturing process of the aluminum foil, an aluminum alloy ingot obtained by DC casting was subjected to homogenization heat treatment in a heating furnace at a predetermined temperature and time. After that, after performing hot rolling, cold rolling is performed multiple times, and intermediate annealing is performed at a predetermined temperature and time during the cold rolling. , 12, 15, and 20 μm, aluminum foil C was cold rolled to a thickness of 7 μm, and aluminum foil D was cold rolled to a thickness of 7 μm. Furthermore, aluminum foils A, B, and D were subjected to final annealing at a predetermined temperature and time.

Note that since the homogenization heat treatment temperature is high, once the temperature of the ingot reaches the homogenization heat treatment temperature, the ingot may be cooled to a temperature at which hot rolling can be started. Furthermore, the homogenization heat treatment time may be within a general treatment time and is not necessarily limited to the time shown in Table 1. Further, since the intermediate annealing conditions do not have a large effect on the properties of the examples and comparative examples of the present invention, the heat treatment temperature and heat treatment time may be within the range of general operating conditions.

<Measurement of X-ray diffraction intensity of aluminum foil>
For each of the obtained aluminum foil samples A to D, X-ray diffraction was performed to calculate the ratio P ₂₀₀ of the diffraction intensity I ₂₀₀ indicating the (200) plane and the ratio P ₂₂₀ of the diffraction intensity I 220 indicating the ( ₂₂₀ ) plane. The strength was measured. The X-ray diffraction intensity was measured using a fully automatic multi-purpose horizontal X-ray diffractometer (Smart Lab manufactured by Rigaku Co., Ltd.), and the analysis software was RINT2000PC (Ver. 3.0.0.0) using CuKα radiation, 40 kV, 30 mA. Perform X-ray diffraction under the following conditions, and measure the X-ray diffraction intensity (integrated intensity after background removal) of the (111) plane, (200) plane, (220) plane, and (311) plane by X-ray diffraction. I went by that. Using the obtained values of the X-ray diffraction intensity of each surface, the relative diffraction intensity ratio was calculated using the above-mentioned (Equation 1). As for the X-ray diffraction intensity of aluminum foil, as mentioned above, the results (measured values) are almost the same whether measuring aluminum foils A to D alone or measuring aluminum foils A to D in an aluminum laminate. I found out that I can get it.

<Measurement of composition of aluminum foil>
To determine the composition of the aluminum foil, measure 1.00 g of each sample for measurement from the obtained aluminum foils A to D, and analyze it by inductively coupled plasma emission spectrometry (device name: ICPS-8100 manufactured by Shimadzu Corporation). It was measured by

<Measurement of mechanical strength of aluminum foil>
The tensile strength, 0.2% proof stress, and elongation at break of the aluminum foil were measured at room temperature (20°C) using a tensile tester (Toyo Seiki Co., Ltd. Strograph VES5D, strain rate 20 mm/min, sample width 7 mm, distance between chucks) 100 mm). In addition, 0.2% yield strength is determined by finding a straight line from the obtained load-displacement curve that has the same slope as the elastic straight line in the elastic deformation region and passes through a point 0.2% away from the initial sample length from the elastic modulus intersection. The point that intersects with the load-displacement curve was defined as the load at the proof point, and the value was calculated by dividing the load by the cross-sectional area of the sample.

<Resin film>
The resin films O, P, Q, R, and S to be laminated on the aluminum foil described above include a 12 μm thick nylon resin film O (“ONBC84W#” manufactured by Unitika Co., Ltd.), and a 12 μm thick PET (polyethylene terephthalate) resin film P. (“PTM” manufactured by Unitika Co., Ltd.), PET resin film Q with a thickness of 12 μm (“ET510” manufactured by Toyobo Co., Ltd.), PET resin film R with a thickness of 16 μm (“T4100” manufactured by Toyobo Co., Ltd.), and PBT (polymer) with a thickness of 15 μm Butylene terephthalate) resin film S (“DE048” manufactured by Toyobo Co., Ltd.) was prepared.

<Measurement of mechanical strength of resin film>
The tensile strength, 0.2% proof stress, and elongation of the above resin films O to S were measured at room temperature (20°C) using a tensile tester (Toyo Seiki Co., Ltd. Strograph VES5D, strain rate 20 mm/min, sample width 7 mm, The distance between the chucks was 100 mm). In addition, 0.2% yield strength is determined by finding a straight line from the obtained load-displacement curve that has the same slope as the elastic straight line in the elastic deformation region and passes through a point 0.2% away from the initial sample length from the elastic modulus intersection. The point that intersects with the load-displacement curve was defined as the load at the proof point, and the value was calculated by dividing the load by the cross-sectional area of the sample. The results are shown in Table 2.

<Preparation of aluminum laminate>
<Preparation of aluminum laminate>
Aluminum laminates shown in Examples 1 to 4 and Comparative Examples 1 to 10 were produced using the above aluminum foils A to D and resin films O to S. Specifically, according to the combinations and adhesive application amounts (g/m ² ) shown in Table 3, resin films O to S were applied to one side of aluminum foils A to D using a polyurethane dry laminating adhesive. By laminating, aluminum laminates of Examples 2 and 3 and Comparative Examples 2 and 4 were produced. In addition, for Examples 1 and 4 and Comparative Examples 1, 3, and ⁵ to 10, aluminum foil -D were laminated to produce aluminum laminates of Examples and Comparative Examples.

<0.2% proof stress of aluminum laminate in rolling direction>
The yield strength of the aluminum laminates of Examples 1 to 4 and Comparative Examples 1 to 10 was measured by tensile testing the aluminum laminates according to the following method using Strograph VES5D manufactured by Toyo Seiki. The aluminum laminate was cut out by 200 mm in the rolling direction (RD) of the aluminum foil in the aluminum laminate and 7 mm in the width direction (TD) perpendicular to the rolling direction (RD). The distance between the chucks was 100 mm, and the tensioning speed was 20 mm/min. From the load-displacement curve obtained here, find the point where a straight line that has the same slope as the elastic direct line in the elastic deformation region and passes through a point 0.2% away from the initial sample length from the elastic modulus intersection intersects the load-displacement curve. The load at the proof point was taken as the load, and the value obtained by dividing the sample cross-sectional area from the load was taken as the value of 0.2% proof stress in the roll processing direction.

<Evaluation of flexibility of aluminum laminate against repeated bending>
The flexibility of the aluminum laminates of Examples 1 to 4 and Comparative Examples 1 to 10 against repeated bending was determined by attaching a bending test jig using a φ150 mm face plate to a multifunctional compact tabletop durability tester manufactured by Yuasa System Equipment Co., Ltd. The measurement was performed by performing a 90° left and right bending test.

First, an aluminum laminate was cut out by 100 mm in the rolling direction (RD) of the aluminum foil in the aluminum laminate and 7 mm in the width direction (TD) perpendicular to the rolling direction (RD). The cut out aluminum laminate is placed on the outside of a cable wire with an outer diameter of 1.6 mmΦ whose conductor is annealed copper wire and whose outside is insulated with foamed polyethylene. A copper braided wire with an outer diameter of 2.0 mm was wound along the length so as to match the rolling direction (RD), and then a copper braided wire with an outer diameter of 2.0 mm was wound around the outer side of the wire.The wire was placed in a polyolefin resin tube with an outer diameter of 3.6 mm, and heated at a temperature of 120 mm. Cable wires coated with the aluminum laminates of Examples and Comparative Examples were prepared by shrinking the polyolefin resin tube by holding it at ℃ for 2 minutes.

The above-obtained cable wire was bent to the left by 90° using a mandrel with a bending radius of 5 mm and returned to its original state, and then bent to the right by 90° and returned to its original state for one cycle (times). It was then bent multiple times. While bending the cable wire, the electrical resistance value at both ends of the aluminum laminate was continuously measured using a digital multimeter GDM-9061 manufactured by Tecsio Technology Co., Ltd. until the electrical resistance value became 1.0Ω or more. The number of times n of bending was measured and used as an index indicating the flexibility of the aluminum laminate against repeated bending. In other words, the reason why the electrical resistance value of the aluminum laminate increases to 1.0Ω or more is considered to be due to damage such as breakage of all or part of the aluminum foil (layer) in the aluminum laminate. , the higher the number of times n of bending before breaking, etc., the better the flexibility against repeated bending. The above bending test was performed three times for each sample, and the average values are shown in Table 3.

<Measurement of peel strength of aluminum laminate>
The peel strength of the aluminum laminate was determined by bending the aluminum foil of the laminate by 180° at room temperature (20°C) using a tensile testing machine (Toyo Seiki Co., Ltd. Strograph VES5D), and then stacking the remaining laminate without bending. The peeling was performed at a peeling rate of 200 mm/min, a sample width of 7 mm, and a distance between chucks of 100 mm, with the interface being peeled at 180°. In addition, the peel strength (N/15 mm) as meant in the specification of this application is measured by measuring the peel strength with the above-mentioned strip-shaped sample with a sample width of 7 mm, and converting the value to the peel strength when the sample width is 15 mm. (15/7 times).

<Measurement of mechanical strength of aluminum laminate>
The tensile strength, 0.2% yield strength, and elongation at break of the aluminum laminate were measured at room temperature (20°C) using a tensile tester (Toyo Seiki Co., Ltd. Strograph VES5D, strain rate 20 mm/min, sample width 7 mm, between chucks). distance of 100 mm). In addition, 0.2% yield strength is determined by finding a straight line from the obtained load-displacement curve that has the same slope as the elastic straight line in the elastic deformation region and passes through a point 0.2% away from the initial sample length from the elastic modulus intersection. The point that intersects with the load-displacement curve was defined as the load at the proof point, and the value was calculated by dividing the load by the cross-sectional area of the sample.

<Evaluation of change in resistance value per unit cross-sectional area>
Simultaneously with the measurement of the above tensile test, the resistance value of the aluminum laminate during the tensile test was measured using a digital multimeter GDM-9061 manufactured by Techsio Technology Co., Ltd. by the following method. This is adopted as an alternative evaluation of electromagnetic shielding performance. When cutting an aluminum laminate to the size described above and performing a tensile test, bend both ends of the test piece by 10 mm and connect it to the lead wire, so that the aluminum foil on one side of the aluminum laminate with a length of 200 mm and a width of 7 mm is The resistance value was measured. The measured resistance value was calculated as a change in resistance value per unit cross-sectional area by dividing the difference up to 30 mm of elongation by the cross-sectional area of the aluminum foil. For aluminum laminates with an elongation at break of less than 30.0 mm, the resistance value was set to infinity (∞) since the elongation had already broken when the elongation was 30.0 mm.

<Evaluation of width strain ratio of aluminum laminate>
The width-to-strain ratio of the aluminum laminate was measured by subjecting the aluminum laminate to a tensile test using the tensile testing machine described above according to the following method. The aluminum laminate was cut out to a length of 150 mm in the machine flow direction (RD) and 7 mm in the width direction (TD). The distance between the chucks was 50 mm, the tensile speed was 20 mm/min, the width of the aluminum laminate at an elongation of 20.0% was measured, and the width strain ratio was calculated.

The measurement results of the 0.2% proof stress in the roll processing direction, elongation at break, width strain ratio in the roll processing width direction, change in resistance value per unit cross-sectional area, and peel strength of the aluminum laminate are shown in Table 3 below.

<Consideration>
From Table 3, when comparing the aluminum laminates of the examples and the aluminum laminates of the comparative examples, the aluminum laminates of the examples 1 to 4 can not reach the aluminum laminates of the comparative examples 1 to 10, preferably 20,000. It was found that an extremely high bending number n of at least 25,000 times, more preferably 25,000 times or more, was achieved, and the material had excellent flexibility against repeated bending. In addition, since the aluminum laminates of Examples 1 to 4 had a change in electrical resistance value per unit cross-sectional area of 600 mΩ/mm ² or less, most of the aluminum foils (layers) in the aluminum laminates were not damaged. It is inferred that the aluminum foil maintains the high electromagnetic wave shielding properties unique to aluminum foil.

In addition, in order to obtain extremely high flexibility against repeated bending while maintaining high electromagnetic shielding properties like the aluminum laminates of Examples 1 to 4, at least one resin film (layer) must be added to the aluminum foil (layer). ) are laminated, and the thickness t ₁ of the aluminum foil (layer) is set to 40% or more and 60% or less with respect to the thickness t ₀ of the aluminum laminate, and the 0.2% yield strength in the rolling direction of the aluminum laminate is 50. It is extremely important to make the aluminum laminate higher than 0 N/mm ² , to make the elongation at break in the roll processing direction of the aluminum laminate 30.0% or more, and to make the width strain ratio of the aluminum laminate in the roll processing width direction to 0.60 or more. It turned out to be.

Furthermore, in order to obtain the above-mentioned properties, from Tables 1 and 3, the aluminum foil used for the aluminum laminate must have (111) plane, (200) plane, (220) plane and (311) plane in The ratio P 200 of the diffraction intensity I ₂₀₀ indicating the (200) plane to the total diffraction intensity I ₀ which is the sum of each diffraction intensity indicating each of the above is 30% or more and 60% or less, and the ratio P ₂₀₀ to the total diffraction intensity I ₀ is (220) The ratio P ₂₂₀ of the diffraction intensity I ₂₂₀ indicating a plane is 10% or more and 40% or less, the iron content in the aluminum foil is 0.4% by mass or more and 1.7% by mass or less, or It has been found that it is effective to set the thickness of the aluminum foil (layer) to 5 μm or more and 300 μm or less.

In addition, as for the resin film, from Tables 2 and 3, it is effective to include polyethylene terephthalate resin, and for the aluminum laminate, the peel strength between the resin film (layer) and the aluminum foil (layer) is It was found that 3.0 N/15 mm or more is preferable.

1a, 1b, 1c, 1d, 1e, 1f... Aluminum laminate 2... Aluminum foil (layer)
3...Resin film (layer)
4...Adhesive (layer)
5...Printing layer, coating layer

Claims (8)

In an aluminum laminate in which at least a resin film and an aluminum foil are laminated,
The thickness _t1 of the aluminum foil is 40% or more and 60% or less with respect to the thickness _t0 of the aluminum laminate,
The 0.2% yield strength of the aluminum laminate in the roll processing direction is greater than 50.0 N/mm ² ,
An aluminum laminate for electromagnetic shielding tape, characterized in that the elongation at break in the roll processing direction of the aluminum laminate is 30.0% or more, and the width strain ratio of the aluminum laminate in the roll processing width direction is 0.60 or more. body. The aluminum foil has a (200) plane for a total diffraction intensity _I0 , which is the sum of diffraction intensities showing each of the (111) plane, (200) plane, (220) plane, and (311) plane in X-ray diffraction. The ratio P ₂₀₀ of the diffraction intensity I ₂₀₀ shown is 30% or more and 60% or less, and the ratio P ₂₂₀ of the diffraction intensity I ₂₂₀ showing the (220) plane to the total diffraction intensity I ₀ is 10% or more and 40% or less. The aluminum laminate according to claim 1. The aluminum laminate according to claim 2, wherein the resin film and the aluminum foil are laminated via an adhesive, and the peel strength between the resin film and the aluminum foil is 3.0 N/15 mm or more. The aluminum laminate according to claim 3, wherein the aluminum foil contains 0.4% by mass or more and 1.7% by mass or less of iron. The aluminum laminate according to claim 4, wherein the thickness of one layer of the aluminum foil is 5 μm or more and 300 μm or less. The aluminum laminate according to claim 5, wherein the resin film contains at least a polyester resin. The aluminum laminate according to claim 6, wherein the resin film contains at least a polyethylene terephthalate resin. The aluminum laminate according to any one of claims 1 to 7, further comprising a printed layer or a coating layer.

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