JP6582156B1 - Electrolytic copper foil, and negative electrode for lithium ion secondary battery, lithium ion secondary battery, copper clad laminate and printed wiring board using the electrolytic copper foil - Google Patents

Abstract

The tensile strength measured using each cut copper foil obtained by cutting the electrolytic copper foil from one end to the other end in the width direction at intervals of 100 mm satisfies the following requirements (I) to (III). -Requirement (I): The average value of the tensile strength of each said cut copper foil in a normal state is 400 MPa or more and 650 MPa or less. -Requirement (II): The dispersion | distribution (sigma) 2 of the tensile strength of each said cutting copper foil in a normal state is 18 [MPa] 2 or less. -Requirement (III): The average value of the tensile strength of each said cut copper foil in the state after heat-processing at 150 degreeC for 1 hour is 350 Mpa or more.

Description

  The present invention relates to an electrolytic copper foil, a negative electrode for a lithium ion secondary battery, a lithium ion secondary battery, a copper clad laminate, and a printed wiring board using the electrolytic copper foil.

  A lithium ion secondary battery (hereinafter, simply referred to as “battery”) is composed of, for example, a positive electrode, a negative electrode, and a non-aqueous electrolyte, and is mainly used for a mobile phone, a notebook type personal computer, and the like. ing. In recent years, the demand for automobile applications has also increased rapidly.

A negative electrode of a lithium ion secondary battery has a negative electrode active material layer formed on the surface of a negative electrode current collector, and a copper foil is generally used for the negative electrode current collector. In particular, compared to rolled copper foil, electrolytic copper foil (hereinafter sometimes simply referred to as “copper foil”) that can easily achieve both conductivity and strength and can be thinned at low cost is widely used. ing.
A negative electrode of a lithium ion secondary battery using such a copper foil is formed by applying carbon particles or the like as a negative electrode active material layer on the surface of the copper foil, drying, and further pressing.

  In recent years, along with the market expansion of lithium ion secondary batteries, there has been a demand for improvement in productivity as well as improvement in battery characteristics. In response to these requirements, for example, in order to increase the capacity of the battery, the thickness of the active material layer and the press pressure have been increased. The number of stripe coating of the active material layer is increased. In addition, lithium ion secondary batteries are desired to be lighter, and copper foils are being made thinner.

  However, under the manufacturing conditions corresponding to the various requirements described above, wrinkles and cracks in the copper foil, shape defects of the slit end face, etc. are likely to occur during coating of the active material layer, pressing, and slitting. In some cases, the productivity of the battery is reduced.

  In addition, when the lithium ion secondary battery is charged and discharged, the active material layer expands and contracts, and the stress may be applied to other members such as a copper foil and a separator. Such a stress load causes a short circuit due to the destruction of other members such as a separator or a fire. In addition, the stress load on the copper foil may cause the active material layer to peel from the copper foil, and may cause the copper foil to break down such as wrinkles and breakage, leading to a decrease in battery life. . Usually, the stress applied to the copper foil is further increased as the thickness and density of the active material layer are increased.

  With respect to the various problems as described above, in the prior art, the copper foil has a tensile strength of a predetermined value or more, or the elongation of the copper foil is a predetermined value or more, and the elongation anisotropy is reduced. Techniques for improving the mechanical properties of the foil have been proposed (see Patent Documents 1 to 4).

  However, at the time of actual battery production, as described in Patent Document 1, simply improving the mechanical properties such as the tensile strength and elongation of the copper foil cannot sufficiently solve the above problems. Further, as in Patent Documents 2 and 3, the crystal grain size and orientation are controlled, or as in Patent Document 4, a ten-point average roughness including only information in the height direction with respect to the two-dimensional sectional shape of the surface ( Controlling Rzjis) and reducing the elongation anisotropy were insufficient to reduce the strength variation due to the location of the wide copper foil. In particular, recently, there has been an increase in the application of a plurality of active material layers to a wide (for example, 600 mm or more) copper foil. In such a case, the load on the copper foil tends to increase as the thickness and density of the active material layer increase.

In addition, recently, using a copper foil having a roughened surface, an adhesive resin such as an epoxy resin is previously pasted on the roughened surface of the copper foil, and the adhesive resin is semi-cured (B stage). ), And a printed wiring board (particularly a build-up wiring board) is manufactured by thermocompression bonding of the copper foil and the insulating board with the insulating resin layer side as the insulating substrate side. .
In the production of such a printed wiring board, there has been a problem that wrinkles are generated in the copper foil due to pressing when the copper foil and the insulating substrate are thermocompression bonded.
Therefore, the development of a copper foil that is less likely to be wrinkled during production has been demanded for printed wiring board applications.

Japanese Patent No. 5588607 Japanese Patent No. 5074611 Japanese Patent No. 5718476 Japanese Patent No. 6248233

  Accordingly, the present invention provides a battery that has high mechanical strength and heat resistance, and does not generate wrinkles, breakage, or slit end face shape even if it is wide even if a plurality of stripe coatings are applied during battery manufacture. Electrolytic copper foil excellent in productivity (hereinafter simply referred to as “battery productivity”), and a negative electrode for lithium ion secondary batteries and a lithium ion secondary battery using the electrolytic copper foil For the purpose. Further, the present invention provides an electrolytic copper foil that is less likely to be wrinkled by a press during production, and a copper-clad laminate and a printed wiring board using the electrolytic copper foil, even when used as a printed wiring board. The purpose is to provide.

  As a result of intensive studies, the inventors have determined that the tensile strength measured using each cut copper foil obtained by cutting the electrolytic copper foil from one end to the other end in the width direction at an interval of 100 mm has a predetermined requirement ( It has been found that by satisfying (I) to (III), an electrolytic copper foil having high mechanical strength and heat resistance and excellent in battery productivity can be obtained even if it is wide, and the present invention is completed. I came to let you. Moreover, it discovered that the above electrolytic copper foil was hard to generate | occur | produce the wrinkle at the time of a press even if it used it for a printed wiring board use.

That is, the gist configuration of the present invention is as follows.
[1] Tensile strength measured using each cut copper foil obtained by cutting an electrolytic copper foil from one end to the other end in the width direction at an interval of 100 mm satisfies the following requirements (I) to (III): Electrolytic copper foil.
-Requirement (I): The average value of the tensile strength of each said cut copper foil in a normal state is 400 MPa or more and 650 MPa or less.
-Requirement (II): The dispersion | distribution (sigma) ² of the tensile strength of each said cutting copper foil in a normal state is 18 [MPa] ² or less.
-Requirement (III): The average value of the tensile strength of each said cut copper foil in the state after heat-processing at 150 degreeC for 1 hour is 350 Mpa or more.
[2] The electrolytic copper foil according to the above [1], wherein the dimension in the width direction is 600 mm or more.
[3] The electrolytic copper foil according to [1] or [2], wherein an average value of elongation in a normal state of each of the cut copper foils is 5.3% or more.
[4] The electrolytic copper foil according to any one of [1] to [3], wherein the conductivity is 88% IACS or more.
[5] The electrolytic copper foil according to any one of [1] to [4], wherein a development area ratio (Sdr) of the glossy surface is 12% or more and 27% or less.
[6] The electrolytic copper foil according to any one of [1] to [5], which is used as a negative electrode current collector of a lithium ion secondary battery.
[7] A negative electrode for a lithium ion secondary battery using the electrolytic copper foil according to [6].
[8] A lithium ion secondary battery using the negative electrode for a lithium ion secondary battery according to [7].
[9] It has a roughened surface on at least one surface of the electrolytic copper foil according to any one of [1] to [5],
The electrolytic copper foil whose development area ratio (Sdr) of the said roughening process surface is 20% or more and 200% or less.
[10] A copper-clad laminate comprising: the electrolytic copper foil according to [9] above; and a resin substrate laminated on the roughened surface of the electrolytic copper foil.
[11] A printed wiring board comprising the copper clad laminate according to [10].

  According to the present invention, an electrolytic copper foil having high mechanical strength and heat resistance and excellent in battery productivity even if it is wide, and a negative electrode for a lithium ion secondary battery using the electrolytic copper foil In addition, a lithium ion secondary battery can be provided. Moreover, according to the present invention, even when used as a printed wiring board application, an electrolytic copper foil that is unlikely to be wrinkled by pressing during production, a copper-clad laminate using the electrolytic copper foil, and a printed wiring board Can be provided.

FIG. 1 is an example of a production apparatus for producing the electrolytic copper foil of the present invention.

  Embodiments of the electrolytic copper foil according to the present invention will be described in detail below.

In the electrolytic copper foil of the present invention, the tensile strength measured using each cut copper foil obtained by cutting at 100 mm intervals from one end to the other end in the width direction satisfies the following requirements (I) to (III): It is characterized by that.
-Requirement (I): The average value of the tensile strength of each said cut copper foil in a normal state is 400 MPa or more and 650 MPa or less.
-Requirement (II): The dispersion | distribution (sigma) ² of the tensile strength of each said cutting copper foil in a normal state is 18 [MPa] ² or less.
-Requirement (III): The average value of the tensile strength of each said cut copper foil in the state after heat-processing at 150 degreeC for 1 hour is 350 Mpa or more.

  In the present specification, “electrolytic copper foil” refers to a copper foil produced by electrolytic treatment, and an untreated copper foil that has not been subjected to surface treatment after foil formation, and subjected to surface treatment as necessary. It means to include any copper foil (surface-treated electrolytic copper foil). Moreover, the foil thickness of an electrolytic copper foil becomes like this. Preferably it is 30 micrometers or less, More preferably, it is 4-15 micrometers. In the following description, “copper foil” means “electrolytic copper foil” unless otherwise specified.

  Moreover, the “width direction” of the copper foil is a direction perpendicular to the transport direction (same as the peeling direction from the cathode electrode) at the time of producing the copper foil, and the copper foil wound in a roll shape In this case, the longitudinal direction corresponds to the transport direction. Further, the “width direction dimension” is a dimension from one end to the other end in the width direction of the copper foil.

  Further, the “cut copper foil” is a copper foil obtained by cutting a copper foil from one end to the other end in the width direction at an interval of 100 mm. Here, the cut copper foil used for evaluating the characteristics of the copper foil is all of the cut copper foil having a width direction dimension of 100 mm (± 5 mm), and the cut copper foil having a width direction dimension of less than 95 mm is a measurement object. Not. For example, in the case of a copper foil having a width direction dimension of 850 mm, when cutting from one end to the other end in the width direction at an interval of 100 mm, nine cut copper foils are obtained, of which the dimension to be measured is the width direction dimension. Are 8 cut copper foils of 100 mm (± 5 mm).

  In addition, the “normal state” means that the copper foil is in an unheated state as it is manufactured and does not have a heat history with heating exceeding 60 ° C., for example, at room temperature (15 to 30 ° C., even below) The same)). Further, the “state after being heat-treated at 150 ° C. for 1 hour” means a state after the copper foil has been heat-treated at 150 ° C. for 1 hour and cooled to room temperature, for example.

  In the conventional high strength copper foil, when a plurality of stripe coatings are applied on a wide copper foil, there is a problem that wrinkles, breakage, defective shape of the slit end face, etc. are likely to occur. As a result of diligent research on such problems, the present inventors have found that the occurrence of the above problems is related to the degree of variation in tensile strength in the width direction of the copper foil. .

  Usually, in the stripe coating, the places where the active material layer is applied and the places where the active material layer is not applied are alternately formed in the width direction of the copper foil, and the places where the load is applied in the width direction of the copper foil and the places where it is not Are alternately present. For copper foil after stripe coating, when processing the press or slit in the production line, if there is a variation in the tensile strength in the width direction of the copper foil, It was found that slips in the width direction, tension fluctuations, etc. are likely to occur. In particular, flapping on the line transport and slipping in the width direction of the copper foil cause wrinkles and breakage, and fluctuations in tension cause wrinkles and slit end face abnormalities (burrs, chips, etc.). .

  Based on the above knowledge, in the present invention, in the copper foil having high strength and excellent heat resistance, the tensile strength varies in the width direction of the copper foil, particularly compared to the conventional copper foil having high strength. It has been found that by reducing the size, the above problems can be solved, and productivity can be improved in the mass production process of the battery.

Furthermore, as a result of intensive investigations on defects in the press process of the printed wiring board, the present inventors have found that wrinkles occur more frequently as the variation in the tensile strength of the copper foil increases.
Based on the above knowledge, the copper foil used in the printed wiring board can also reduce wrinkle defects and improve the productivity of the printed wiring board by reducing the variation in the tensile strength in the width direction as described above. I found.

  The width direction dimension of the copper foil of this invention becomes like this. Preferably it is 300 mm or more, More preferably, it is 600 mm or more, More preferably, it is 900 mm or more, More preferably, it is 1200 mm or more. Such a copper foil is suitable for use in mass production of batteries and printed wiring boards. Moreover, although the upper limit of the width direction dimension of copper foil is based also on the manufacturing equipment of copper foil, it is 2000 mm, for example, and the width direction dimension of copper foil is 1500 mm or less from a viewpoint of reducing the characteristic variation of the width direction. Is preferred.

  The larger the width dimension of the copper foil is, the more preferable it is that the battery and the printed wiring board can be mass-produced. However, the stress applied when manufacturing the battery and the printed wiring board tends to be different in the width direction of the copper foil. . Therefore, the problem as described above is particularly noticeable in the wide copper foil. However, in the present invention, the above problem can be solved by reducing the variation in the tensile strength in the width direction of the copper foil. .

  In the present invention, in order to appropriately evaluate the variation in characteristics in the width direction of the copper foil, in particular, using each cut copper foil obtained by cutting the copper foil at 100 mm intervals from one end to the other end in the width direction. Various measurements are performed and finally the entire copper foil is evaluated. Hereinafter, each requirement will be described in detail.

<Requirement (I)>
In the copper foil of the present invention, the average value of the tensile strength (Ts) of each cut copper foil in a normal state is from 400 MPa to 650 MPa, preferably from 400 MPa to 600 MPa, more preferably from 445 MPa to 600 MPa, More preferably, it is 450 MPa or more and 600 MPa or less. By setting it as the said range, the productivity of a battery can be improved and the battery which has a favorable battery characteristic can be manufactured. On the other hand, when the average value of the tensile strength of each cut copper foil in a normal state is less than 400 MPa, it cannot withstand the influence of the increase in load caused by the electrode material accompanying the increase in capacity of the battery, and the copper foil is wrinkled. There is a tendency. Moreover, when the average value of the tensile strength of each cut copper foil in a normal state exceeds 650 MPa, the elongation of the copper foil is lowered, and the copper foil tends to break.
In addition, when used for a printed wiring board, if the tensile strength in the normal state of the copper foil is less than 400 MPa, the handling properties deteriorate due to the occurrence of wrinkles during the transport of the thin foil sheet product. Moreover, when the tensile strength in the normal state of copper foil exceeds 650 MPa, it becomes easy to generate | occur | produce foil cutting at the time of precipitation manufacture with a drum, and productivity deteriorates.

<Requirement (II)>
In the copper foil of the present invention, the dispersion σ ² of the tensile strength (Ts) of each cut copper foil in a normal state is 18 [MPa] ² or less, preferably 14 [MPa] ² or less, more preferably 11 [MPa]. MPa] ² or less, more preferably 10 [MPa] ² or less. Here, the dispersion σ ² of the tensile strength of each cut copper foil is an index of variation in the tensile strength in the width direction of the copper foil, and the larger the value, the greater the variation in tensile strength. The copper foil of the present invention can effectively prevent the occurrence of local wrinkles and sagging in the electrode manufacturing process because the tensile strength dispersion σ ² of each cut copper foil in the normal state is in the above range. Further, it is possible to effectively prevent the generation of wrinkles due to pressing in the printed wiring board manufacturing process. On the other hand, when the dispersion σ ² of the tensile strength of each cut copper foil in the normal state is more than 18 [MPa] ² , there is a large variation in the tensile strength in the width direction of the copper foil, and the load is applied to the copper foil in the electrode manufacturing process. Since the applied stress varies in the width direction of the copper foil, local wrinkles and sagging occur, and the productivity of the battery tends to decrease. Also, in the printed wiring board manufacturing process, wrinkles due to pressing tend to be prominent. Note that the lower limit of the tensile strength dispersion σ ² of each cut copper foil in a normal state may be, for example, 0 [MPa] ² .

<Requirement (III)>
In the copper foil of the present invention, the average value of the tensile strength (Ts) of each cut copper foil after being heat-treated at 150 ° C. for 1 hour is 350 MPa or more, preferably 380 MPa or more, more preferably 400 MPa or more. It is. By setting it as the said range, sufficient intensity | strength can be maintained at the time of the process to a battery, it is excellent in the durability to the load at the time of charging / discharging of a battery, and the cycle life of a battery improves. On the other hand, when the average value of the tensile strength of each cut copper foil in a state after being heat-treated at 150 ° C. for 1 hour is less than 350 MPa, the strength is reduced during processing of the battery, and when the battery is charged / discharged, It cannot endure, and the copper foil is liable to break, and the cycle life of the battery tends to be reduced. In addition, the upper limit of the average value of the tensile strength of each cut copper foil after being heat-treated at 150 ° C. for 1 hour is, for example, 550 MPa, preferably 450 MPa from the viewpoint of having an appropriate elongation even after heating. May be.
Also, in the production of the printed wiring board, when the average value of the tensile strength of each cut copper foil in a state after being heat-treated at 150 ° C. for 1 hour is 350 MPa or more, even after heating in the substrate lamination step, Since the crystal grains are kept fine, the etching property is improved. On the other hand, when the average value of the tensile strength is less than 350 MPa, the crystal grains tend to increase after heating in the substrate laminating step, and the copper particles are hardly dissolved by etching, so that the etching property is deteriorated.

  In the above requirements (I) to (III), the tensile strength is a value measured under the evaluation conditions described in this example.

<Elongation (El)>
In the copper foil of the present invention, the average value of the elongation (El) in the normal state of each cut copper foil is preferably 5.3% or more, more preferably 6.0% or more, and further preferably 7.5%. As mentioned above, More preferably, it is 9.0% or more. By setting it as the said range, durability with respect to the stress loaded on copper foil at the time of charging / discharging of a battery improves. In addition, the upper limit of the average value of the elongation in the normal state of each cut copper foil is, for example, 13.0%, preferably 11.0% from the viewpoint of high strength.
Moreover, it is preferable that it is the same range as the normal case also about the average value of the elongation of each cutting copper foil in the state after heat-processing at 150 degreeC for 1 hour.
The elongation is a value measured under the evaluation conditions described in this example.

<Development area ratio (Sdr)>
Conventionally, the ten-point average roughness Rzjis is generally used as a parameter representing the surface shape of the copper foil. However, in the ten-point average roughness Rzjis, information in the height direction with respect to the two-dimensional cross-sectional shape of the surface is used. However, it was not included in the evaluation. On the other hand, the development area ratio (Sdr) includes three-dimensional information on the surface, so that more appropriate characteristic evaluation can be performed.

  The developed area ratio (Sdr) means the ratio of the area added by the surface properties with reference to the ideal surface having the size of the measurement region, and is defined by the following formula (1).

  In the above formula (1), x and y are plane coordinates, and z is a coordinate in the height direction. z (x, y) indicates the coordinates of a certain point, and by differentiating this, the slope at that coordinate point is obtained. A is the plane area of the measurement region.

  In addition, the development area ratio (Sdr) is measured and evaluated for unevenness on the surface of the copper foil by, for example, a three-dimensional white interference microscope, a scanning electron microscope (SEM), an electron beam three-dimensional roughness analyzer, etc. Can be sought. In general, the development area ratio (Sdr) tends to increase as the spatial complexity of the surface texture increases, regardless of changes in the surface roughness (Sa).

In the copper foil of the present invention, the development area ratio (Sdr) of the glossy surface is preferably 27% or less, more preferably 20% or less, still more preferably 18.5% or less, and still more preferably. 17% or less. By setting it as the said range, the variation in the intensity | strength of the width direction of copper foil can further be reduced, and the productivity of a battery further improves. Moreover, by setting it as the said range, generation | occurrence | production of the wrinkle by a press is suppressed also in the manufacturing process of a printed wiring board. Note that the lower limit of the development area ratio (Sdr) of the glossy surface may be, for example, 12% from the viewpoint of the coatability of the active material layer.
In the copper foil of the present invention, the development area ratio (Sdr) of the rough surface is preferably 92% or less, more preferably 90% or less, still more preferably 80% or less, and still more preferably. 70% or less. By setting it as the said range, since the stress load to copper foil occurs uniformly when the application of an active material layer is made at the time of electrode manufacture, wrinkles and sagging are reduced, and productivity is improved. Moreover, by setting it as the said range, generation | occurrence | production of the wrinkle by a press is suppressed also in the manufacturing process of a printed wiring board. The lower limit of the development area ratio (Sdr) of the rough surface may be 62%, for example.
Here, the development area ratio (Sdr) of the glossy surface and the roughened surface is a value measured under the evaluation conditions described in this example.
The glossy surface (sometimes referred to as “S (shiny) surface”) refers to the surface on the side that is in contact with the cathode drum during the production of the electrolytic copper foil, and is a rough surface (referred to as “M (matte) surface”). Sometimes refers to the surface opposite the glossy surface. In addition, in this specification, when calling it a glossy surface and a rough surface, it refers to an untreated copper foil surface that has not been subjected to a surface treatment after foil production, and a roughening treatment was performed on the glossy surface and the rough surface. It shall be distinguished from the roughened surface.

The copper foil of the present invention may have a roughened surface on at least one surface of the copper foil, and the developed area ratio (Sdr) of the roughened surface is preferably 20% or more and 200% or less. More preferably, it is 25% or more and 197% or less. Such a copper foil is particularly suitable for use as a printed wiring board. For example, when the development area ratio (Sdr) of the roughened surface is less than 20%, the adhesiveness when adhering the adhesive resin to the surface tends to decrease, and when it exceeds 200% In some cases, the etching factor is lowered and it is difficult to form fine wiring.
The development area ratio (Sdr) of the roughened surface is a value measured under the evaluation conditions described in this example.

<Conductivity>
The copper foil of the present invention has a conductivity of preferably 88% IACS or more, more preferably 90% IACS or more, still more preferably 91% IACS or more, and still more preferably 92% IACS or more. . By setting it as the said range, when a battery is produced, the internal resistance of a negative electrode electrode falls and the cycling characteristics of a battery improve. Moreover, if it is the said range, it is suitable also when using copper foil as a printed wiring board.
Here, the conductivity is a value measured under the evaluation conditions described in this example.

<Method for producing electrolytic copper foil>
Next, the preferable manufacturing method of the electrolytic copper foil of this invention is demonstrated.
The electrolytic copper foil of the present invention supplies, for example, an electrolytic solution between an insoluble anode made of titanium coated with a platinum group element or an oxide element thereof and a titanium cathode drum provided to face the anode, While the cathode drum is rotated at a constant speed, a direct current is passed between both electrodes to deposit copper on the surface of the cathode drum, and the deposited copper is peeled off from the cathode drum surface and continuously wound. be able to. In addition, the apparatus which performs such manufacture is an example.

  As the electrolytic solution, for example, a sulfuric acid-copper sulfate aqueous solution having a copper concentration of 50 to 100 g / L and a sulfuric acid concentration of 40 to 120 g / L can be suitably used.

Moreover, you may add at least 1 sort (s) of an organic or inorganic additive to an electrolyte solution from a viewpoint of the strengthening of copper foil.
Examples of organic additives include thiourea (CH ₄ N ₂ S) or water-soluble thiourea derivatives (such as ethylene thiourea), glue, gelatin, polyethylene glycol, starch, and cellulose-based water-soluble polymers (carboxyl methyl cellulose, hydroxy). Polymeric polysaccharides such as ethyl cellulose) and water-soluble polymer compounds such as polyethyleneimine and polyacrylamide can be used.
Moreover, as an inorganic additive, sodium tungstate, ammonium tungstate, etc. can be used as a supply source of a trace amount of metal elements in addition to NaCl and HCl as a supply source of chloride ions.

It is preferable to add 1 to 30 mg / L of chloride ions as an inorganic additive, and further add 3 to 19 mg / L of thiourea or a water-soluble thiourea derivative as an organic additive.
Moreover, it is preferable to adjust the liquid temperature of electrolyte solution to 40-60 degreeC and the average current density in a cathode electrode surface to 40-60 A / dm < ² >.

By the way, the strength of the copper foil is generally increased by adding an additive to the electrolytic solution. The effect of the additive is mainly to control the incorporation of impurities into the foil, or the crystal orientation and the crystal grain size, by adsorbing the additive to the crystal nucleus of the copper surface layer during electrodeposition.
However, the rate at which nucleation and nucleation occur varies depending on the manufacturing conditions such as the concentration of the electrolytic solution, the current density, the liquid temperature, the type and concentration of the additive. In particular, in the case of conditions aimed at increasing the strength, the nuclear growth is often dominant.
The additive is adsorbed on the copper crystal grains and taken into the copper foil, so that the strength of the copper foil can be increased. However, the fact that the nucleus growth is dominant, that is, the adsorption point of the additive is sparse. It means that it is easy to become. High-strength copper foil produced under such conditions tends to vary in strength.

In the present invention, for example, by making the initial electrodeposition layer of copper finer and smoothed by the following method, the adsorption point of the additive can be made uniform in the surface direction of the copper foil. It was found that the variation in tensile strength in the direction can be reduced.
Specifically, it is preferable to use PR (Periodic Reverse) pulse electrolysis only at the time of initial electrodeposition in addition to the conventional foil forming process.

In the case of conventional foil production using a direct current, copper nuclei are generated on the cathode substrate, and copper grows starting from the nuclei.
However, by using PR pulse electrolysis at the time of initial electrodeposition, the copper deposition step (at the time of positive pulse energization) and the dissolution step (at the time of negative pulse energization) are repeated when copper crystal nuclei are generated. The shape of the copper crystal nuclei generated in the precipitation process is reduced by the subsequent melting process. In the subsequent precipitation step of the melting step, new copper crystal nuclei are generated on the cathode substrate in addition to the reduced copper crystal nuclei. By repeating them, fine nucleation is obtained, and the initial electrodeposition layer is made fine and smooth. As a result, it is considered that the adsorption point of the additive can be obtained uniformly.

Suitable conditions for PR pulse electrolysis are, for example, as follows.
Positive pulse current density _I on: _20~80A / dm ²
Positive pulse energization time _t on: _50~200 milliseconds (ms)
Negative pulse current density I _rev : −80 to −20 A / dm ²
Negative pulse energization time t _rev : 50 to 200 milliseconds (ms)
Pulse stop time t _off : 50 to 200 milliseconds (ms)
Number of repetitions of positive pulse-negative pulse: 10-30 times

Calculated in PR pulse electrolysis as described above, in particular, from the viewpoint of obtaining a homogeneous initial electrodeposited layer, the product of the positive pulse current density I _{on (A} / dm ²⁾ and the positive pulse current supply time t _{on (ms)} positive pulse integrated current value Q1 that is _{(= I on × t on)} , a negative pulse integration calculated by the product of the negative pulse current density _I rev (a / dm ²⁾ and the negative pulse current supply time _{t rev} (ms) It is preferable that the current value Q2 (= I _rev × t _rev ) satisfies the relationship of the following formula (i).
0.5 ≦ | Q2 / Q1 | ≦ 0.9 (i)

  When the absolute value | Q2 / Q1 | of the ratio of the negative pulse integrated current value Q2 to the positive pulse integrated current value Q1 is larger than 0.9, the contribution of the melting process is large, and the total amount of copper precipitation nuclei is insufficient. When the ratio is smaller than 0.5, the contribution of the precipitation process is large, and fine nucleation tends to be difficult to obtain.

  According to the above-described method, a minimum necessary and extremely thin and uniform initial electrodeposition layer can be formed, thereby obtaining a uniform deposited layer in the thickness direction of the copper foil in a later step. It is done. Therefore, the additive is uniformly adsorbed on both the surface direction and the thickness direction of the copper foil, and a high-strength electrolytic copper foil having a small strength variation in the width direction is obtained.

In addition, as an apparatus suitable for copper foil manufacture of the above methods, a manufacturing apparatus like FIG. 1 is mentioned, for example. FIG. 1 shows a schematic diagram of a manufacturing apparatus.
As shown in FIG. 1, the manufacturing apparatus 1 mainly includes a cathode drum 11, a PR pulse electrode 12, an anode 13, and a bathtub 14. The PR pulse electrode 12 and the anode 13 are provided to face the cathode drum 11, and the electrolytic solution 20 is supplied therebetween. The cathode drum 11 rotates at a constant speed in the direction of the arrow 11a, and the PR pulse and the direct current are energized between the electrodes of the PR pulse electrode 12 and the anode 13, respectively. Copper precipitates on the surface. The copper deposited on the surface of the cathode drum 11 is finally peeled off in the direction of the arrow 30 a to be made as a copper foil 30. In the manufacturing apparatus 1, the outside of the bathtub 14 and various pipes are not shown, but the electrolytic solution 20 is continuously supplied from the outside of the bathtub 14 in the direction of the arrow 20 a, and the cathode drum 11 and the electrolyte solution 20 after passing between the PR pulse electrode 12 and the anode 13 are discharged to the outside of the bathtub 14 through a discharge pipe.

The electrolytic copper foil of the present invention may be further subjected to a surface treatment on at least one of the surfaces of the copper foil as necessary.
As the copper foil surface treatment, for example, chromate treatment, or Ni or Ni alloy plating, Co or Co alloy plating, Zn or Zn alloy plating, Sn or Sn alloy plating, and further chromate treatment was performed on the above various plating layers. Examples thereof include inorganic rust preventive treatments such as those, organic rust preventive treatments such as benzotriazole, and silane coupling agent treatments. In addition to rust prevention, these surface treatments, for example, increase the adhesion strength with the active material when used as a negative electrode current collector of a lithium ion secondary battery, and further prevent the charge / discharge cycle efficiency of the battery from decreasing. Fulfill. These rust prevention treatments are generally performed at a very thin thickness relative to the copper foil thickness. Therefore, there is almost no effect on the tensile strength.

  Before the surface treatment is applied to the copper foil, it is possible to perform a roughening treatment on the surface of the copper foil as necessary. As the roughening treatment, for example, a plating method or an etching method can be suitably employed. These roughening treatments play a role of further improving the adhesiveness and the like with the active material when the copper foil is used as the negative electrode current collector of the lithium ion secondary battery. Moreover, also when using copper foil for preparation of a printed wiring board, a roughening process plays the role which improves the adhesiveness with an insulated substrate. In the production of a printed wiring board, from the viewpoint of satisfactorily forming a fine circuit, the roughening treatment is performed so as to obtain a roughening treatment surface having a desired surface property, particularly a desired development area ratio (Sdr). It is desirable to be controlled. The roughening treatment is also generally performed with a very thin thickness with respect to the copper foil thickness. Therefore, there is almost no effect on the tensile strength.

  As roughening by the plating method, an electrolytic plating method and an electroless plating method can be employed. Roughened particles can be formed by metal plating made of one kind of metal among Cu, Co and Ni, or alloy plating containing two or more kinds of metals among these.

  Moreover, as the roughening by the etching method, for example, a method by physical etching or chemical etching is preferable. For example, as physical etching, a method of etching by sandblasting or the like can be mentioned. Further, as the chemical etching, a method of etching with a processing solution or the like can be mentioned. In particular, in the case of chemical etching, a known treatment liquid containing an inorganic or organic acid, an oxidizing agent, and an additive can be used as the treatment liquid.

Hereinafter, a preferable example of the roughening treatment by the plating method will be specifically described.
The roughening treatment is performed by sequentially performing roughening plating treatment 1 and roughening plating treatment 2 on at least one surface of a copper foil serving as a base (hereinafter sometimes simply referred to as “copper foil base”). It can be carried out. The preferable conditions for the roughening plating treatment 1 and the roughening plating treatment 2 are as follows. The following conditions are preferred examples, and the types and amounts of additives and electrolysis conditions can be appropriately changed and adjusted as necessary within the range not impeding the effects of the present invention.

・ Roughening plating 1
Copper sulfate: 18-23g / L as copper concentration
(It means “copper sulfate containing an amount corresponding to 18 to 23 g / L as copper metal”. The same shall apply hereinafter.)
Sulfuric acid: 96-105 g / L
Cobalt (II) sulfate heptahydrate: As a cobalt concentration, 2.8 to 4.2 g / L
Liquid temperature: 32-40 degreeC
Current density: 32-36 A / dm ²
Time: 1 second to 2 minutes

・ Roughening plating 2
Copper sulfate: Copper concentration of 45 to 55 g / L
Sulfuric acid: 112-121 g / L
Liquid temperature: 59-64 degreeC
Current density: 6-12 A / dm ²
Time: 1 second to 2 minutes

  In particular, when the copper foil of the present invention is used for printed wiring board applications, the development area ratio on the roughened surface of the copper foil from the viewpoint of achieving both adhesion to the insulating substrate and formation of a good fine circuit. It is effective to control (Sdr) within a range of 20% to 200%. A roughened surface having such a desired surface property can be produced by satisfying the conditions for the roughening treatment.

  Even when the above-described surface treatment is performed after the roughening treatment, the surface treatment such as the rust prevention treatment is performed with a very thin thickness, so that the development area ratio (Sdr) of the roughening treatment surface is reduced. There is almost no influence. Therefore, the development area ratio (Sdr) of the roughened surface adjusted by the above-mentioned roughening treatment is maintained even after the surface treatment such as the rust prevention treatment.

<Anode for lithium ion secondary battery and lithium ion secondary battery>
The copper foil according to the present invention is preferably used as a negative electrode current collector of a lithium ion secondary battery. By using the copper foil according to the present invention, even when a plurality of stripe coatings are applied at the time of battery production, wrinkles, breaks, defective shape of the slit end face and the like are hardly generated, and the battery productivity can be improved.
Since the negative electrode for a lithium ion secondary battery using the copper foil according to the present invention as a negative electrode current collector has high strength and high heat resistance, durability during battery manufacture and charge / discharge is improved. . Moreover, the lithium ion secondary battery using such a negative electrode has a good yield at the time of manufacture, and is excellent in battery characteristics (for example, cycle characteristics).

  The negative electrode for lithium ion secondary batteries can be formed by a known method using the copper foil of the present invention. For example, a negative electrode for a lithium ion secondary battery is formed by applying a slurry containing carbon particles or the like as a negative electrode active material layer on the surface of a copper foil, drying, and pressing.

  Moreover, a lithium ion secondary battery can be formed by a well-known method using the said negative electrode.

<Copper-clad laminate and printed wiring board>
The copper foil which concerns on this invention can also be used as a copper clad laminated board and a printed wiring board provided with this. By using the copper foil according to the present invention, it is possible to suppress the occurrence of wrinkles due to the press at the time of thermocompression bonding of the copper foil and the insulating substrate during the production of the printed wiring board, and the productivity of the printed wiring board can be reduced. Can be improved.

  The copper foil of the present invention used for the production of a printed wiring board has a roughened surface on at least one surface of the copper foil, and the developed area ratio (Sdr) of the roughened surface is 20% or more and 200% or less. It is preferable that According to such a copper foil, it is possible to suppress the occurrence of wrinkle defects due to pressing, and it is possible to achieve both good fine wiring formation.

  It is preferable that a copper clad laminated board is equipped with the copper foil of this invention, and the resin-made board | substrates laminated | stacked on the roughening process surface of this copper foil. Such a copper-clad laminate can be formed by a known method using the copper foil of the present invention. For example, in a copper clad laminate, a copper foil having a roughened surface on at least one surface and an insulating substrate (resin base material) are arranged such that the roughened surface (sticking surface) and the resin base material face each other. It is manufactured by laminating and sticking. Examples of the insulating substrate include a flexible resin substrate and a rigid resin substrate. The copper foil of the present invention is particularly suitable in combination with a rigid resin substrate.

  Moreover, what is necessary is just to manufacture by bonding the surface treatment copper foil which has a silane coupling agent layer, and an insulated substrate by hot press, when manufacturing a copper clad laminated board. It is produced by applying a silane coupling agent on an insulating substrate, and bonding the insulating substrate coated with the silane coupling agent and a surface-treated copper foil having a rust-proofing layer on the outermost surface by a hot press. The copper-clad laminate also has the same effect as the present invention.

  Moreover, it is preferable that a printed wiring board is provided with the said copper clad laminated board. Such a printed wiring board can be formed by a known method using the copper-clad laminate.

  By the way, among the printed wiring boards, the build-up wiring board is required to highly integrate various electronic components. Correspondingly, the wiring pattern is required to have a high density, and the fine line width and line An inter-pitch wiring pattern, that is, a so-called fine pattern printed wiring board has been demanded. For example, multilayer boards used for servers, routers, communication base stations, in-vehicle boards, etc. and multilayer boards for smartphones require printed wiring boards with high density and extremely fine wiring (hereinafter referred to as “high density wiring boards”). Has been.

  High-layer wiring boards of AnyLayer (interlayer connection using laser vias with a high degree of freedom in arrangement) are mainly used for the main board of smartphones. Wiring with a pitch (hereinafter referred to as “L & S”) of 30 μm or less is required. High-density wiring boards are conventionally manufactured by a subtractive method using a photoresist at a printed wiring board manufacturer, and it is effective to reduce the thickness of the copper foil to make the L & S finer. It has been known. However, when molding a high-density wiring board with a large area exceeding 500 mm square, if the copper foil has a thickness of 9 μm or less, there is a problem that the copper foil is wrinkled after pressing the insulating resin and the copper foil. there were.

  For example, Japanese Patent No. 6158573 discloses a technique for forming fine wiring by refining the average crystal grain size of the bulk of an ultrathin copper layer. Since it was not taken, when copper foil was thin, the defect occurred frequently in the press process.

  On the other hand, the copper foil of the present invention has a small variation in the tensile strength in the width direction as described above. Generation can be suppressed, and productivity can be improved in the production of high-density wiring boards.

  As mentioned above, although embodiment of this invention was described, the said embodiment is only an example of this invention. The present invention includes all aspects included in the concept and claims of the present invention, and can be variously modified within the scope of the present invention.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated still in detail, the following is an example of this invention.

(Production Examples 1 to 9 and Comparative Production Examples 1 to 4)
As shown in FIG. 1, an electrolytic solution 20 is supplied between a titanium cathode drum 11 (width: 1200 mm, diameter: 2100 mm) and a PR pulse electrode 12 and an insoluble anode 13 provided to face the cathode drum 11. Then, while rotating the cathode drum 11 at a constant speed, a PR pulse and a direct current were passed between the two poles to deposit copper on the surface of the cathode drum 11 to produce a copper foil 30 having a thickness of 10 μm. Thereafter, the copper foil 30 was peeled off from the cathode drum 11, both ends were cut, and wound into a roll to obtain a copper foil having a width direction dimension of 1100 mm.

In all of Production Examples 1 to 9 and Comparative Production Examples 1 to 4, the electrolyte solution 20 was prepared such that the copper concentration was 80 g / L, the sulfuric acid concentration was 100 g / L, and the chloride ion concentration was 20 mg / L. A sulfuric acid-copper sulfate electrolyte was used. The temperature of the electrolytic solution was adjusted to 55 ° C., the average current density was 45 A / dm ² , and the liquid flow rate was adjusted to 1.0 m / s.

Moreover, about the kind of additive added to this electrolyte solution, its addition density | concentration, and electrolysis conditions of PR pulse electrolysis, it adjusts as shown in Table 1 about each of manufacture examples 1-9 and comparative manufacture examples 1-4. did. In addition, the rotational speed of the cathode drum 11 was suitably adjusted according to electrolysis conditions so that the thickness of the copper foil 30 might be 10 micrometers.
In addition, among the types of additives listed in Table 1, both “thiourea” and “ethylenethiourea” were manufactured by Tokyo Chemical Industry Co., Ltd.

(Comparative Production Example 5)
In Comparative Example Production 5, a copper foil 30 was obtained in the same manner as in Production Example 1 except that copper was deposited on the surface of the cathode drum 11 without applying a PR pulse between both electrodes.

(Comparative Production Example 6)
In Comparative Production Example 6, a copper foil 30 was obtained in the same manner as in Production Example 2 except that copper was deposited on the surface of the cathode drum 11 without applying a PR pulse between both electrodes.

(Examples 1-9 and Comparative Examples 1-6)
[Characteristic evaluation]
About the copper foil produced by the said manufacture example and comparative manufacture example, the characteristic evaluation shown below was performed. The evaluation conditions for each characteristic are as follows, and each measurement was performed at room temperature unless otherwise specified. The results are shown in Table 2.

<Preparation of cut copper foil>
As the normal copper foil, an unheated copper foil as produced was used.
In addition, after the copper foil in the state after heat treatment at 150 ° C. for 1 hour, the normal copper foil was heated at 150 ° C. for 1 hour in an inert gas oven (INH-21CD-S, manufactured by Koyo Thermo Systems Co., Ltd.) What was cooled to room temperature was used.
Each copper foil was cut at 100 mm intervals from one end to the other end in the width direction to obtain 11 cut copper foils (100 mm × 200 mm, thickness 10 μm) corresponding to each state.

<Tensile test>
The tensile test is performed using IPC-TM-650 with a tensile tester (type 1122, manufactured by Instron) using two types of cut copper foils in a normal state and a state after heat treatment at 150 ° C. for 1 hour. It was performed in accordance with the provisions of
First, a test piece (0.5 inch × 6 inch) having a width direction dimension of 0.5 inch from a position 10 mm from one end (cut end) in the width direction of one cut copper foil is spaced approximately 5 mm in the width direction. 5 were cut out. Using the obtained test piece, tensile strength and elongation were measured under conditions of a distance between chucks of 70 mm and a tensile speed of 50 mm / min. Here, the elongation refers to the elongation rate when the test piece is broken. And the average value computed from the obtained measured value (each N = 5) was made into the tensile strength and elongation of this one cutting copper foil. Further, similarly for each of the other 10 cut copper foils, the tensile strength and the elongation were obtained, and finally, the tensile strength and the elongation (each N = 11) of each of the 11 cut copper foils were averaged. The average value of tensile strength and the average value of elongation were determined.
This measurement was carried out for two types of copper foils in a normal state and a state after heat treatment at 150 ° C. for 1 hour.
In addition, about normal copper foil, dispersion | distribution (sigma) ² of tensile strength was calculated | required from the tensile strength of each 11 cut copper foils.

<Development area ratio (Sdr)>
The development area ratio (Sdr) is measured by measuring the surface shape using a white-light interference optical microscope (Wyko Control GT-K, manufactured by BRUKER) with a normal cut copper foil as a measurement object, and further analyzing the shape. Was done. Shape analysis is VSI measurement method using a high resolution CCD camera, light source is white light, measurement magnification is 50 times, measurement area is 96.1 μm × 72.1 μm, Lateral Sampling is 0.075 μm, speed is 1, Backscan is The test was performed under the conditions of 10 μm, Length of 10 μm, and Threshold of 3%, and data processing was performed after filtering of TermsRemoval (Cylinderand Tilt) and DataRestore (Method: legacy, iterations 5). Specifically, it was performed as follows.
First, the surface shape was measured at the center of one of the cut copper foils, and the shape analysis was performed to obtain the development area ratio (Sdr). Furthermore, the development area ratio (Sdr) was similarly measured for the other 10 cut copper foils, and finally, the measured value (N = 11) of the development area ratio (Sdr) of each of the 11 cut copper foils was averaged. And the average value was made into the expansion | deployment area ratio (Sdr) of copper foil. The results are shown in Table 2.

<Conductivity>
The electrical conductivity was measured according to the provisions of JISH0505-1975 using an Agilent 4338B Milliometer (manufactured by Agilent Technologies) with a normal cut copper foil as the measurement target. Specifically, it was performed as follows.
One test piece (0.5 inch × 6 inch) was cut out from one cut copper foil, and the conductivity was measured three times by the four-terminal method using the test piece with a distance between terminals of 100 mm. The average value calculated from the obtained measured value (N = 3) was defined as the conductivity of the one cut copper foil. Further, the conductivity is similarly obtained for the other 10 cut copper foils, and finally, the conductivity (N = 11) of each of the 11 cut copper foils is averaged, and the average value is determined as the conductivity of the copper foil. It was. The results are shown in Table 2.

[Evaluation of lithium ion secondary battery applications]
Using the copper foils produced in the above production examples and comparative production examples as negative electrode current collectors, lithium ion secondary batteries were produced, and the following characteristic evaluation was performed. The evaluation conditions for each characteristic are as follows, and each measurement was performed at room temperature unless otherwise specified. The results are shown in Table 2.

(Manufacture of positive electrode)
First, LiCoO ₂ powder, graphite powder, and polyvinylidene fluoride powder are mixed at a mass ratio of 90: 7: 3, to which N-methylpyrrolidone and ethanol are added and kneaded as a solvent, A positive electrode paste was prepared.
Next, the obtained positive electrode agent paste was uniformly applied onto an aluminum foil having a thickness of 15 μm. The aluminum foil coated with the positive electrode paste was dried in a nitrogen atmosphere to volatilize the solvent, and then roll-rolled to produce a sheet having a total thickness of 150 μm. The sheet was cut into a width of 43 mm and a length of 285 mm, and then an aluminum foil lead terminal was attached to one end thereof by ultrasonic welding to form a positive electrode.

(Production of negative electrode and evaluation of productivity)
The copper foil used for the negative electrode current collector is a normal copper foil produced in Production Examples and Comparative Production Examples.
First, the copper foil was cut into a band shape (the width direction of the band shape was parallel to the width direction of the copper foil) so as to have a width direction dimension of 720 mm.
Next, natural graphite powder (average particle size 10 μm) and polyvinylidene fluoride powder are mixed at a mass ratio of 90:10, and N-methylpyrrolidone and ethanol are added as a solvent to the mixture and kneaded. A negative electrode paste was prepared.
Next, the obtained negative electrode paste was applied on both sides of the strip-shaped copper foil in a double stripe shape with a width of 300 mm along the longitudinal direction of the copper foil. The copper foil coated with the negative electrode paste was dried in a nitrogen atmosphere, the solvent was volatilized, and then roll-rolled to compress the entire thickness to 150 μm. Thereafter, the coated part was cut into a width of 43 mm and a length of 280 mm. A nickel foil lead terminal was attached to one end by ultrasonic welding to form a negative electrode.
Finally, it was visually confirmed whether or not abnormalities such as wrinkles in the copper foil and burrs in the cut portion were observed, and evaluated as battery productivity. The case where wrinkles or breakage does not occur in the copper foil is “excellent (◎)”, and either minor wrinkles or burrs are generated in the copper foil. In addition, at least one of burrs and occurrence of burrs, which were expected to affect the subsequent evaluation of battery characteristics, were evaluated as “impossible (×)”.

(Production of battery and evaluation of battery characteristics)
The whole was wound with a 25 μm-thick polypropylene separator sandwiched between the produced positive electrode and negative electrode, and this was accommodated in a nickel-plated battery can, and the negative lead terminal was spot welded to the bottom of the can. Next, after placing the top cover of the insulating material and inserting the gasket, the lead terminal of the positive electrode and the aluminum safety valve were connected by ultrasonic welding, and a non-aqueous electrolyte consisting of propylene carbonate, diethyl carbonate and ethylene carbonate was added to the battery can. Injected into. Thereafter, a lid was attached to the safety valve, and a sealed structure type lithium ion secondary battery having an outer diameter of 14 mm and a height of 50 mm was assembled.
A charge / discharge cycle test was performed in which the assembled battery was charged at a charging current of 100 mA to 4.2 V and discharged at a discharge current of 100 mA until it reached 2.4 V. The battery characteristics were evaluated with the number of cycles when the discharge capacity of the battery was below 800 mAh as the cycle life (cycle characteristics). The results are shown in Table 2.
The cycle life was evaluated as “excellent (◎)” for 500 times or more, “good (◯)” for 300 times or more and less than 500 times, and “impossible (×)” for less than 300 times. A copper foil whose evaluation is “impossible (×)” indicates that the copper foil is not suitable for this application. “Good (◯)” indicates that the copper foil is suitable, and among them, “Excellent (中 で も)” indicates that the copper foil has better battery characteristics.

(Comprehensive evaluation)
Comprehensive evaluation was performed based on the following evaluation criteria. In this example, A and B were regarded as acceptable levels in the overall evaluation.
A (excellent): Both the above-described productivity and battery characteristics are evaluated as “excellent (」) ”.
B (accepted): There is no “impossible (×)” evaluation for both the productivity and battery characteristics, and at least one of the productivity and battery characteristics is a “good (◯)” evaluation.
C (failure): At least one of the above productivity and battery characteristics is “impossible (×)” evaluation.

  As shown in Table 2, the copper foils produced in Production Examples 1 to 9 have a predetermined tensile strength in a normal state, and the tensile strength variation in the width direction which is long at this time is small, and further after heat treatment Even in this state, high tensile strength is maintained (Examples 1 to 9). It was confirmed that such copper foil of Examples 1-9 was excellent in both the productivity at the time of production of a lithium ion secondary battery, and the battery characteristic as a lithium ion secondary battery.

  On the other hand, the copper foil produced in Comparative Production Example 1 has an excessively high tensile strength and is inferior in elongation (Comparative Example 1). Moreover, the copper foil of comparative manufacture example 2 has low tensile strength in the normal state and the state after heat processing (comparative example 2). Therefore, it was confirmed that the electrolytic copper foils of Comparative Examples 1 and 2 were inferior in battery characteristics as a lithium ion secondary battery.

  Moreover, as for the copper foil produced by the comparative manufacture examples 3-6, the tensile strength in a normal state varies in the width direction (comparative examples 3-6). Therefore, it was confirmed that the copper foils of Comparative Examples 3 to 6 were inferior in productivity when producing lithium ion secondary batteries.

(Examples 11 to 19 and Comparative Examples 13, 15 and 16)
[Evaluation of printed wiring board applications]
The copper foils produced in Production Examples 1 to 10 and Comparative Production Examples 3, 5 and 6 were used as copper foil bases, and the surface treatment was performed on one surface of each copper foil under the conditions shown below. A copper foil (thickness 12 μm) was obtained.
About the obtained surface-treated copper foil, the characteristic evaluation shown below was performed. The evaluation conditions for each characteristic are as follows, and each measurement was performed at room temperature unless otherwise specified. The results are shown in Table 3.

(Formation of roughened layer)
First, the copper foil used for a copper foil base | substrate is the normal copper foil (width direction dimension 1100mm) produced by the said manufacture examples 1-10 and the comparative manufacture examples 3, 5 and 6. FIG.
Next, the roughening plating process 1 and the roughening plating process 2 which were shown below were performed in order with respect to the surface shown in Table 3 of a copper foil base | substrate, and the roughening process layer was formed.

・ Roughening plating 1
Copper sulfate: Copper concentration of 21 g / L
Sulfuric acid: 97g / L
Cobalt (II) sulfate heptahydrate: 3.6 g / L as cobalt concentration
Liquid temperature: 36 ° C
Current density: 32 A / dm ²
Time: 1-30 seconds

・ Roughening plating 2
Copper sulfate: 50g / L as copper concentration
Sulfuric acid: 120 g / L
Liquid temperature: 62 ° C
Current density: 10 A / dm ²
Time: 1-30 seconds

(Formation of surface treatment layer)
Next, the following nickel layer, zinc layer, chromate treatment layer, and silane coupling agent layer were sequentially formed on the roughened surface of the copper foil on which the roughened layer was formed.

-Formation of nickel layer (underlying layer) The copper layer on which the roughened layer was formed was subjected to electrolytic plating under the Ni plating conditions shown below to obtain a nickel layer (Ni adhesion amount 0.23 mg / dm ²⁾ was formed. The plating solution used for nickel plating contains nickel sulfate, ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ), boric acid (H ₃ BO ₃ ), and the nickel concentration is 5.3 g / L, ammonium persulfate. The concentration is 28.0 g / L and the boric acid concentration is 19.5 g / L. The temperature of the plating solution is 23.5 ° C., the pH is 3.9, the current density is 2.6 A / dm ² , and the plating time is 1 to 30 seconds.

Zinc layer further formation of (heat-resistant layer), by electrolytic plating with Zn plating under the following conditions on the nickel layer to form a zinc layer (adhesion amount 0.05 mg / dm ² of Zn). The plating solution used for zinc plating contains zinc sulfate heptahydrate and sodium hydroxide, and the zinc concentration is 10 g / L and the sodium hydroxide concentration is 29 g / L. The temperature of the plating solution is 30 ° C., the current density is 5 A / dm ² , and the plating time is 1 to 30 seconds.

Formation of chromate treatment layer (rust prevention treatment layer) Further, a chromate treatment layer (Cr adhesion amount 0.05 mg / dm ² ) was formed on the zinc layer by electrolytic plating under the Cr plating conditions shown below. . The plating solution used for chromium plating contains chromic anhydride (CrO ₃ ), and the chromium concentration is 3.1 g / L. The temperature of the plating solution is 20 ° C., the pH is 2.1, the current density is 0.6 A / dm ² , and the plating time is 1 to 30 seconds.

-Formation of a silane coupling agent layer Furthermore, the process shown below was performed and the silane coupling agent layer was formed on the chromate treatment layer. That is, methanol or ethanol was added to the silane coupling agent aqueous solution and adjusted to a predetermined pH to obtain a treatment liquid. This treatment liquid was applied to the chromate treatment layer of the surface-treated copper foil, held for a predetermined time, and then dried with warm air to form a silane coupling agent layer. As the silane coupling agent, 3-mercaptopropyltrimethoxysilane (KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd.) was used, and an aqueous silane coupling agent solution was prepared under conditions of a concentration of 1.0% and pH 4.0. .

<Roughened surface area (Sdr)>
The development area ratio (Sdr) was measured for the roughened surface of the surface-treated copper foil obtained above. The measurement was performed in the same manner as the measurement for the cut copper foil. The results are shown in Table 3.

(Manufacture of copper-clad laminates and evaluation of press defects)
The surface-treated copper foil obtained above is cut into a size of 200 mm × 200 mm, and the roughened surface of the surface-treated copper foil is treated with an FR4 resin base material (EI-6765, manufactured by Sumitomo Bakelite Co., Ltd.). Then, heating and pressure bonding were performed for 1 hour under the conditions of 170 ° C. and surface pressure of 1.5 MPa to produce a copper-clad laminate. With this method, 30 copper-clad laminates were produced and visually checked for wrinkles.
About the copper clad laminated board by which the wrinkle was confirmed, it counted as the number of wrinkle defects. The evaluation of wrinkle defects is “excellent (◎)” when the number of wrinkle defects is 0 to 1, “good” when the number of wrinkle defects is 2 to 4, and the number of wrinkle defects is In the case of 5 or more, it was evaluated as “impossible (×)”. Table 3 shows the number of wrinkle defects and the evaluation results.

(Etching factor evaluation)
The surface-treated copper foil obtained above was cut into a size of 200 mm × 200 mm, and a resist pattern having an L & S of 30/30 μm was formed on the roughened surface of the surface-treated copper foil by a subtractive method. . Etching was then performed to form a wiring pattern. A dry resist film was used as the resist, and a mixed solution containing copper chloride and hydrochloric acid was used as the etching solution. Then, the etching factor (Ef) of the obtained wiring pattern was measured. The etching factor is expressed by the following equation, where H is the thickness (μm) of the copper foil, B is the bottom width (μm) of the formed wiring pattern, and T is the top width (μm) of the formed wiring pattern. This is the value indicated by. The foil thickness H of the copper foil was the thickness of the surface-treated copper foil. The dimensions of the bottom width B and the top width T were measured using a microscope with respect to the wiring pattern when the just etch position (the position of the resist end and the position of the bottom of the wiring pattern were aligned). .
Ef = 2H / (BT)
The evaluation of the etching factor is “excellent (）)” when the Ef value is 3.5 or more, and “good (◯)” when the Ef value is 2.6 or more and less than 3.5. When the value of Ef was less than 2.6, it was evaluated as “impossible (×)”. Table 3 shows the value of Ef and the evaluation results.
In addition, when the value of Ef is small, the verticality of the side wall in the wiring pattern is broken, and when forming a fine wiring pattern with a narrow line width, unmelted copper foil occurs between adjacent wiring patterns, There is a risk of short-circuiting and risk of disconnection.

(Evaluation of adhesion)
The surface-treated copper foil obtained above was cut into a size of 200 mm × 200 mm, and the roughened surface of the surface-treated copper foil was layered on the FR4 resin base material (same as above), 170 ° C., surface pressure Heating and pressure bonding were performed for 2 hours under conditions of 1.5 MPa to produce a copper-clad laminate.
Using the produced copper-clad laminate as a measurement sample, the copper foil was etched to form a circuit wiring having a width of 1 mm, and a test piece was prepared. Next, the resin substrate side of the test piece is fixed to a stainless steel plate with a double-sided tape, and the circuit wiring portion (copper foil portion) is peeled off by pulling at a speed of 50 mm / min in the 90 ° direction, and the peel strength ( kN / m). The peel strength was measured using a Tensilon universal material testing machine (manufactured by A & D Co., Ltd.).
Evaluation of adhesion is “good (◯)” when the peel strength (kN / m) is 0.6 kN / m or more, and when the peel strength (kN / m) is less than 0.6 kN / m. Was evaluated as “impossible (×)”. The evaluation results are shown in Table 3.

(Comprehensive evaluation)
Comprehensive evaluation was performed based on the following evaluation criteria. In this example, A and B were regarded as acceptable levels in the overall evaluation.
A (excellent): Both the wrinkle defect and the etching factor are evaluated as “excellent (◎)”, and the adhesion is “good (◯)”.
B (pass): There is no “impossible (×)” evaluation for any of the above-mentioned wrinkle defects, etching factors, and adhesion, and at least one of the wrinkle defects and the etching factors is “good (◯)” evaluations.
C (failure): At least one of the above-mentioned wrinkle failure, etching factor, and adhesion is “impossible (×)” evaluation.

In addition, dispersion | distribution (sigma) ² of the tensile strength (Ts) in the normal state of the copper foil base | substrate shown by Table 3 is the same data as dispersion | distribution (sigma) ² of tensile strength (Ts) in the normal state of the electrolytic copper foil shown by Table 2.

  As shown in Table 3, the copper foils of Examples 1 to 9 produced in Production Examples 1 to 9 have a small variation in tensile strength in the width direction, which is particularly long. When copper-clad laminates were produced using the copper foils of Examples 1 to 9, it was confirmed that generation of wrinkles due to pressing during production can be effectively suppressed (Examples 11 to 19). .

  Further, the surface of the copper foils of Examples 1 to 9 is subjected to a surface treatment so that the developed surface area ratio (Sdr) of the roughened surface is within a predetermined range, whereby the adhesion is good and the etching factor is large. It was confirmed that a printed wiring board was obtained (Examples 11 to 19).

  On the other hand, the copper foils of Comparative Examples 3, 5, and 6 produced in Comparative Production Examples 3, 5, and 6 have different normal tensile strengths in the width direction. Therefore, when a copper clad laminated board was produced using the copper foils of Comparative Examples 3, 5 and 6, it was confirmed that wrinkles due to pressing frequently occurred (Comparative Examples 13, 15 and 16).

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 11 Cathode drum 11a Drum rotation direction 12 PR pulse electrode 13 Anode 14 Bath 20 Electrolyte 20a Electrolyte supply direction 30 Copper foil 30a Stripping direction

Claims (11)

An electrolytic copper foil in which the tensile strength measured using each cut copper foil obtained by cutting the electrolytic copper foil from one end to the other end in the width direction at intervals of 100 mm satisfies the following requirements (I) to (III) .
-Requirement (I): The average value of the tensile strength of each said cut copper foil in a normal state is 400 MPa or more and 650 MPa or less.
-Requirement (II): The dispersion | distribution (sigma) ² of the tensile strength of each said cutting copper foil in a normal state is 18 [MPa] ² or less.
-Requirement (III): The average value of the tensile strength of each said cut copper foil in the state after heat-processing at 150 degreeC for 1 hour is 350 Mpa or more.   The electrolytic copper foil of Claim 1 whose width direction dimension is 600 mm or more.   The electrolytic copper foil of Claim 1 or 2 whose average value of the elongation in the normal state of each said cutting copper foil is 5.3% or more.   The electrolytic copper foil of any one of Claims 1-3 whose electrical conductivity is 88% IACS or more.   The electrolytic copper foil according to any one of claims 1 to 4, wherein a development area ratio (Sdr) of the glossy surface is 12% or more and 27% or less.   The electrolytic copper foil according to any one of claims 1 to 5, which is used as a negative electrode current collector of a lithium ion secondary battery.   The negative electrode for lithium ion secondary batteries using the electrolytic copper foil of Claim 6.   The lithium ion secondary battery using the negative electrode for lithium ion secondary batteries of Claim 7. A roughened surface is provided on at least one surface of the electrolytic copper foil according to any one of claims 1 to 5,
The electrolytic copper foil whose development area ratio (Sdr) of the said roughening process surface is 20% or more and 200% or less.   A copper clad laminate comprising: the electrolytic copper foil according to claim 9; and a resin substrate laminated on a roughened surface of the electrolytic copper foil.   A printed wiring board comprising the copper clad laminate according to claim 10.

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