KR20150114484A - Electrolytic copper foil, processes for producing said electrolytic copper foil, and surface-treated copper foil obtained using said electrolytic copper foil - Google Patents

Abstract

An object of the present invention is to provide an electrolytic copper foil which is excellent in physical properties after heating at a high temperature beyond the conventional electrolytic copper foil and which is also suitable for use in a negative electrode current collector of a lithium ion secondary battery. In order to achieve this object, an electrolytic copper foil or the like is used which is characterized by having a tensile strength of 600 MPa or more in steady state tensile strength and a tensile strength of 470 MPa or more after heating at 350 占 폚 for 1 hour. As the method for producing the electrolytic copper foil, a sulfuric acidic copper electrolytic solution containing polyethyleneimine having a concentration of 20 mg / L to 100 mg / L and a molecular weight of 10,000 to 70,000 and having a chlorine concentration of 0.5 mg / L to 2.5 mg / Is used.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrolytic copper foil, a method for producing the electrolytic copper foil, and a surface treated copper foil obtained by using the electrolytic copper foil. BACKGROUND ART < RTI ID = 0.0 >

The present application relates to an electrolytic copper foil, a method for producing the electrolytic copper foil, and a surface treated copper foil obtained by using the electrolytic copper foil. And more particularly to an electrolytic copper foil excellent in high temperature heat resistance characteristics when subjected to high temperature heating.

BACKGROUND ART Electrolytic copper foil is widely used in various fields such as printed wiring board fields, negative electrode current collectors of lithium ion secondary batteries, and the like. In the printed wiring board, a very high temperature exceeding 250 deg. C may be employed as the processing temperature at the time of bringing the copper foil and the insulating layer material into contact with each other. Since the electrolytic copper foil subjected to the high temperature load is softened and the physical strength is lowered, Various problems were occurring. When an electrolytic copper foil is used as a negative electrode current collector of a lithium ion secondary battery, a high temperature of about 300 캜 may be applied when forming a mixed layer containing a negative electrode active material on the surface of the electrolytic copper foil. At this time, when the electrolytic copper foil used for the negative electrode current collector is softened, the resistance against expansion and contraction when charging / discharging is reduced, and the lithium ion secondary battery may be shortened in some cases. Therefore, studies have been made on an electrolytic copper foil excellent in high temperature heat resistance characteristics when subjected to high temperature heating.

For example, Patent Document 1 discloses a method for producing an electrolytic copper foil which comprises: (A) a dithiocarbamic acid derivative or a salt thereof, ( (B) a thiourea, (C) a water-soluble sulfur compound having a mercapto group or a derivative thereof or a salt thereof, (D) a polyalkylene glycol and (E) a chlorine ion as an additive, Quot; is disclosed. According to Claim 1 of Patent Document 1, when tensile strength and electric conductivity are measured at 20 占 폚 after heating at 240 占 폚 for 10 minutes within 120 minutes after completion of electrodeposition, the tensile strength is 650 MPa or more and the electrical conductivity 80% IACS or more, and the tensile strength at 20 ° C measured 168 hours after the completion of electrodeposition is 90% or more of the tensile strength at 20 ° C measured within 120 minutes after completion of electrodeposition, and within 120 minutes after completion of electrodeposition Quot ;, an electrolytic copper foil having an elongation of not less than 3% measured at 20 캜 is obtained.

Patent Document 2 discloses an electrolytic copper foil which has a low surface roughness (low roughness) suitable as an electrolytic copper foil used in a tape automated bonding method and has a high tensile strength and does not cause tin plating peeling, An insoluble positive electrode comprising titanium sulfate coated with a platinum group element or an oxide thereof and a titanium negative electrode drum opposed to the positive electrode are used as an electrolytic solution of a sulfuric acid-copper sulfate aqueous solution and a direct current Wherein the surface roughness is 2.0 占 퐉 or less by the presence of a nonionic water-soluble polymer, a sulfonate of an active organic sulfur compound, a thiourea compound, and a chloride ion in the electrolytic solution, And the orientation index obtained from the relative diffraction intensity of the 220 copper diffraction peaks measured by the formula And an electrodeposited copper foil having a static strength of 500 MPa after heating at 180 ° C for 1 hour is obtained. "

Patent Document 3 discloses a low surface-touched electrolytic copper foil having a roughened surface that is low in shrinkage and has a low rate of decrease in tensile strength due to the elapse of time or a heat treatment and further has an excellent elongation at a high temperature and a method for producing the same. The presence of hydroxyethyl cellulose, polyethyleneimine, acetylene glycol, a sulfonate of an active organosulfur compound and five additives of chlorine ions in the electrolytic solution containing an aqueous solution allows the electrolytic copper foil to have a surface roughness Rz of 2.5 m or less, , The tensile strength at 25 ° C is not less than 500 MPa and the rate of decrease in tensile strength at 25 ° C measured at 300 minutes after completion of electrodeposition is not more than 10% After 10 minutes of heating treatment at 25 DEG C was 10% or less , And also the electrolytic copper foil to obtain a surface poor elongation in 180 ℃ than 6% ", it is disclosed is.

Patent Document 4 discloses that the copper foil is not softened even when the copper foil is completely stored at room temperature from the completion of foil production to the next production step or by a heat treatment at about 200 to 300 占 폚 in the next step, A high tensile strength electrolytic copper foil having a tensile strength of 400 N / mm ² or more measured at 25 캜 after the stability of the copper foil from the completion of the stamping of the copper foil to the copper foil for the purpose of providing the electrolytic copper foil to be held, have. Then, as disclosed in claim 3 of Patent Document 4, after the foaming of the copper foil is completed and the properties of the copper foil are stabilized, the copper foil is heat treated at 300 ° C for one hour, Quot; high tensile strength electrolytic copper foil having a tensile strength of 400 N / mm ² or more "

Patent Document 5 discloses a technique for supplying an electrolytic copper foil for a lithium ion secondary battery negative electrode capable of fabricating a lithium ion secondary battery which does not deteriorate capacity retention rate even after repeated charge / Quot; after the heat treatment at 200 to 400 ° C, the 0.2% proof stress is 250 N / mm ² or more and the elongation is 2.5% or more. The surface of the electrolytic copper foil on which the active material layer is formed is subjected to rust- And the anti-rust treatment is carried out. Further, the present invention discloses an electrode for a lithium ion secondary battery having the electrolytic copper foil as a current collector. That is, an electrolytic copper foil is used as the negative electrode current collector of the lithium ion secondary battery, and the " 0.2% proof stress " after heating the electrolytic copper foil at 240 占 폚 for 10 minutes is defined.

Patent Document 6 discloses an electrolytic copper foil for forming a fine pitch circuit and a copper foil for a high strength which can be used in place of a corundum alloy foil. In the electrolytic copper foil obtained by electrolysis of a copper electrolytic solution, Wherein the copper foil contains 110 ppm to 400 ppm of sulfur and 150 ppm to 650 ppm of chlorine, the conductivity is 48% IACS or more, and the value of the tensile strength at steady state is 70 kgf / mm ² or more.

Patent Document 7 discloses an electrolytic copper foil having a surface with a low profile equivalent to that of a conventional low profile electrolytic copper foil and having a very large mechanical strength and a method for producing the same, microstructure, and a electrolytic copper foil as small as about unprecedented the variation of their particle size, and a surface having a gloss of a low profile, and the value of the steady state tensile strength very large to 70kgf / mm ² to 100kgf / mm ² mechanically And having a tensile strength value of 85% or more of a value of a normal state tensile strength even after heating (180 占 폚 for 60 minutes).

Patent Document 8 discloses an electrolytic copper foil obtained by electrolyzing a copper electrolytic solution for the purpose of providing an electrolytic copper foil which exhibits various stable characteristics even when the chlorine content varies, the content of iodine in the electrolytic copper foil is 0.003 mass% Preferably, the content of iodine is in the range of 0.003 mass% to 0.03 mass%. &Quot; Electrolytic copper foil " The electrolytic copper foil exhibits a physical property such that the tensile strength after steady state tensile strength of 48 kgf / mm ² to 72 kgf / mm ² and after heating at 350 ° C for 60 minutes is 27.5 kgf / mm ² to 46.3 kgf / mm ² And is suitable for use in a negative electrode current collector of a lithium ion secondary battery.

Japanese Unexamined Patent Application Publication No. 140660 Japanese Patent Application Laid-Open No. 11-174146 Japanese Patent Application Laid-Open No. 2004-339558 Japanese Patent Application Laid-Open No. 2008-285727 Japanese Patent Laid-Open Publication No. 1530106 Japanese Patent Application Laid-Open No. 2009-221592 Japanese Patent Application Laid-Open No. 2008-101267 WO2012 / 002526

However, there is an increasing demand for an electrolytic copper foil used for a negative electrode current collector of a lithium ion secondary battery, which can prevent deformation of a negative electrode current collector generated during charging and discharging. In particular, in the case of the negative electrode of recent lithium ion secondary batteries, an alloy type negative electrode active material having a large change in volume due to charging and discharging may be used. In order to carry the alloy-based negative electrode active material on the negative electrode current collector, the composite material layer is formed by using a strong binder to prevent the active material from collapsing due to a large change in volume during charging and discharging. When the polymerization reaction of the binder is caused, a high temperature of 300 DEG C or more is loaded. Therefore, the electrolytic copper foil used in the negative electrode current collector is not provided with a long life span of the lithium ion secondary battery unless it is provided with a high-temperature heat-resistant property capable of maintaining high strength even after being heated to 300 DEG C or higher.

The electrolytic copper foil disclosed in the above-mentioned Patent Document 4 may have sufficient high-temperature heat resistance characteristics. However, the electrodeposited copper foil in this document is said to have a tensile strength of 400 N / mm ² or more after heat treatment at 300 캜 for 1 hour. However, when the content of the example of the embodiment is examined in detail, (Tensile strength) after heating at 300 ° C for 1 hour after 72 hours from 430 MPa to 500 MPa, and the tensile strength exceeding 500 MPa was not obtained.

In addition, the recent electrolytic copper foil is not limited to the field of the printed circuit board, and thinning is remarkable. As the electrolytic copper foil becomes thinner, wrinkles tend to occur at the time of handling. From the viewpoint of preventing occurrence of wrinkles during such handling, it is desirable that the electrolytic copper foil has high physical properties not only after high-temperature heating but also in a steady state.

Therefore, the present application aims at providing an electrolytic copper foil having good high-temperature heat resistance characteristics and being usable as a negative electrode current collector for a printed wiring board and a lithium ion secondary battery.

Therefore, as a result of the study of the inventors of the present invention, the "electrolytic copper foil in both the" steady state physical property "and the" physical property after high temperature heating "was superior to the conventional electrolytic copper foil. It was found that the electrolytic copper foil according to the present application is suitable for use in the negative electrode current collector of a lithium ion secondary battery. The outline of the invention relating to the present application will be described below.

Electrolytic copper foil: The electrolytic copper foil according to the present application is characterized in that the tensile strength after steady state tensile strength of 600 MPa or more and 350 占 폚 for 1 hour is 470 MPa or more.

In addition, the electrolytic copper foil according to the present application has a high physical property such that the 0.2% proof stress after heating at 350 DEG C for 1 hour is not less than 370 MPa.

The electrodeposited copper foil according to the present application has a steady state elongation of 2.5% or more and an elongation at break without practical problems.

The electrodeposited copper foil according to the present application has a C content of 100 μg / g to 450 μg / g, an N content of 50 μg / g to 620 μg / g, an O content of 400 μg / g to 3200 μg / g, and an S content of 110 μg / g And the content of Cl is in the range of 20 μg / g to 115 μg / g and the relationship of {Cl / (C + N + O + S + Cl)} × 100 5 mass% Heat-resistant properties.

Method for producing electrolytic copper foil: The electrolytic copper foil production method according to the present application is a method for producing the electrolytic copper foil as described above, wherein the copper electrolytic solution contains polyethyleneimine having a concentration of 20 mg / L to 100 mg / L and a molecular weight of 10000 to 70,000, And a sulfuric acidic copper electrolytic solution having a chlorine concentration of 0.5 mg / L to 2.5 mg / L is used.

Surface-treated copper foil: The surface-treated copper foil according to the present application is characterized by being obtained by using the above-mentioned electrolytic copper foil.

The electrodeposited copper foil according to the present application has a physical property of "normal state tensile strength of 600 MPa or more" and "tensile strength after heating at 350 ° C for 1 hour" of 470 MPa or more. That is, the electrolytic copper foil of the present application is excellent in both the " physical properties in steady state " and " physical properties after high temperature heating ". Therefore, even in the case of a thin electrolytic copper foil, generation of wrinkles is small and good handling characteristics are obtained. Further, even when used as a negative electrode current collector of a lithium ion secondary battery, such an electrolytic copper foil has a low resistance to tensile strength at the time of carrying the negative electrode active material, and therefore has high resistance to expansion and contraction at the time of charging and discharging , It is possible to prolong the life of the battery.

The electrolytic copper foil can be used as a surface-treated copper foil which is subjected to roughening treatment, rust-proofing treatment or the like in accordance with purposes, and can be widely used in fields such as printed wiring boards and lithium ion secondary batteries.

Further, in the electrolytic copper foil manufacturing method according to the present application, since a simple bath composition can be adopted as compared with the sulfuric acid acidic copper electrolytic solution used in producing the conventional electrolytic copper foil, the solution stability is excellent, The load of the treatment can be reduced, and the bath management and the management cost at the time of manufacturing the electrolytic copper foil can be easily reduced.

Hereinafter, the form of electrolytic copper foil, the form of electrolytic copper foil, and the form of surface treated copper foil obtained by using the electrolytic copper foil will be described in this order.

Form of electrolytic copper foil: The electrolytic copper foil according to the present application is a copper foil which has not been subjected to surface treatment such as rust prevention treatment and roughening treatment, and its thickness is not particularly limited. The electrodeposited copper foil according to the present application described below is specified by its physical properties, although it will be described here. The value of this physical property shows almost the same value between the " electrolytic copper foil " and the " surface treated copper foil "

The electrolytic copper foil according to the present application is characterized in that it has a "normal state tensile strength of 600 MPa or more" and a physical property of "tensile strength after heating at 350 ° C for 1 hour" of 470 MPa or more. The electrolytic copper foil having the " steady state tensile strength of 600 MPa or more " However, at the same time, there is no electrolytic copper foil showing a physical property of "tensile strength after heating at 350 ° C for 1 hour is not less than 470 MPa". In order to obtain an electrolytic copper foil having a physical property of "tensile strength after heating at 350 ° C for 1 hour" of 470 MPa or more, an electrolytic copper foil having a physical property of "normal state tensile strength of 600 MPa or more" is used.

When the electrolytic copper foil has a " normal state tensile strength of 600 MPa or more ", electrolytic copper foils having a thickness of 9 m or less are preferable because wrinkles are less likely to occur during handling and workability is improved. At the same time, when an electrolytic copper foil having physical properties of "a tensile strength after heating at 350 ° C for 1 hour is 470 MPa or more" is used as a negative electrode current collector of a lithium ion secondary battery, the provision of a high quality lithium ion secondary battery with a long battery life Which is preferable. If the electrolytic copper foil having such physical properties is used for the negative electrode current collector, even if the polymerization reaction of the binder is carried out at a temperature of 300 DEG C or more in order to support the alloy negative electrode active material, the strength of the electrolytic copper foil decreases. In terms of "tensile strength after heating at 350 ° C for 1 hour", it is more preferable that "tensile strength after heating at 350 ° C for 1 hour exceeds 500 MPa". This is because even if the heat treatment time becomes longer, a high tensile strength can be stably provided. In addition, in the case of an electrolytic copper foil having such high-temperature heat resistance characteristics, it becomes possible to design a negative electrode current collector having a small thickness.

In addition, the electrolytic copper foil of the present application is preferably "0.2% proof strength after heating at 350 ° C for 1 hour is not less than 370 MPa". In the case of a copper foil composed mainly of copper, which is a nonferrous material, there is no yield point as shown in the steel in the stress-strain curve. Therefore, when performing an objective evaluation as a non-ferrous material, "0.2% proof stress" is used instead of the yield point. The " 0.2% proof stress " and the above-mentioned " tensile strength " do not show perfect correlation, but when the value of the 0.2% proof stress is high, the tensile strength also tends to increase. When the 0.2% proof stress after heating at 350 占 폚 for 1 hour is 370 MPa or more, the fluctuation of the tensile strength of the electrolytic copper foil after heating tends to decrease and the above-mentioned "tensile strength after heating at 350 占 폚 for 1 hour" Physical properties can be stably obtained. Therefore, in the case of the electrolytic copper foil according to the present application, the "0.2% proof stress after heating" and the "tensile strength after heating" are separately evaluated as separate indices, whereby the evaluation of the high temperature heat resistance property against heating can be assured. Hereinafter, the high-temperature heat resistance characteristics exhibited by the electrolytic copper foil of the present application will be described when a stricter high-temperature load is applied. It is more preferable that the electrolytic copper foil according to the present application has a 0.2% proof strength of 410 MPa or more after being heated at 350 占 폚 for 1 hour. It is possible to stably obtain a tensile strength exceeding 500 MPa after heating at 350 DEG C for 1 hour.

Further, even when a high temperature load of 350 占 폚 for 4 hours is applied, the electrolytic copper foil according to the present application preferably has a high tensile strength of "470 MPa or more tensile strength after heating at 350 占 폚 for 4 hours". Further, in the case of the electrolytic copper foil according to the present application, it is more preferable to have a high tensile strength of "500 MPa or more tensile strength after heating at 350 占 폚 for 4 hours". The electrodeposited copper foil according to the present application preferably has a high 0.2% proof strength of "0.2% proof strength after heating at 350 占 폚 for 4 hours is not less than 370 MPa". In the case of the electrolytic copper foil according to the present application, it is more preferable to have a 0.2% proof strength of 0.2 MPa after heating at 350 占 폚 for 4 hours is 410 MPa or more.

In addition, the electrodeposited copper foil according to the present application preferably has a steady state elongation of 2.5% or more. When the steady-state elongation percentage is less than 2.5%, the electrolytic copper foil may be broken when the mixed layer containing the negative electrode active material is formed on the surface of the electrolytic copper foil.

It is considered that the physical properties of the electrolytic copper foil according to the present application described above are obtained by the trace components contained in the electrolytic copper foil. The minor component of the electrolytic copper foil of the present application is preferably the content per mass of the electrolytic copper foil satisfying the following conditions. That is, the C content is in the range of 100 占 퐂 / g to 450 占 퐂 / g ("100 占 퐂 / g to 450 占 퐂 / g or less" (Cl / (C + N + O + S + Cl)} x 100? 5, Mass% of the total mass of the particles. If the condition of the content of the minor component is not satisfied, recrystallization of the crystal structure of the electrolytic copper foil remarkably proceeds due to the high temperature load, and voids are likely to be generated in the crystal structure. The content of the minor component in the present invention is expressed as the content per 1 g of the copper foil, and thus a unit of " μg / g " is used. The value of the Cl content (占 퐂 / g) included in the electrolytic copper foil is the value of C (carbon) content included in the electrolytic copper foil, N (nitrogen (% By mass) obtained by dividing by the value of the content (O (oxygen) content, O (oxygen) content, S (sulfur) content and Cl

It is more preferable that the ratio of trace elements of N (nitrogen) contained in the electrolytic copper foil of the present application satisfies the relationship of {N / (N + S + Cl)} x 100? 20 mass%. If this relationship is not satisfied, the recrystallization of the crystal structure of the electrolytic copper foil remarkably proceeds due to the high temperature load, and voids are likely to be generated in the crystal structure. The fluctuation of the tensile strength and the 0.2% proof stress tends to increase at the heating of 350 DEG C for 1 hour or more. The value of N content (μg / g) contained in the electrodeposited copper foil is the sum of the C content, the S content, and the Cl content (μg / g) contained in the electrolytic copper foil, {N / (N + S + g), and is a 100-percent conversion value (mass%) obtained by multiplying by 100.

Further, it is more preferable that the ratio of the trace amount of Cl (chlorine) contained in the electrolytic copper foil of the present application satisfies the relationship of {Cl / (N + S + Cl)} x 100 20 mass%. If this value exceeds 20 mass%, crystal structure recrystallization of the electrolytic copper foil remarkably progresses due to the high temperature load, and voids are likely to be generated in the crystal structure. No particular lower limit value is provided for this value, but it is considered to be 3.0% by mass. When the content is less than 3.0% by mass, the variation of the tensile strength and the 0.2% proof stress tends to increase. The value of the Cl content (占 퐂 / g) contained in the electrolytic copper foil is the total amount (占 퐂 / g) of the N content, the S content, and the Cl content contained in the electrolytic copper foil, g), and is a 100-percent conversion value (mass%) obtained by multiplying by 100.

Production method of electrodeposited copper foil: The production method of electrolytic copper foil according to the present application is the above-described method of producing an electrolytic copper foil, which contains a polyethyleneimine having a concentration of 20 mg / L to 100 mg / L and a molecular weight of 10000 to 70,000, Sulfuric acidic copper electrolytic solution having a chlorine concentration of 0.5 mg / L to 2.5 mg / L ". The copper concentration and the free sulfuric acid concentration of the "sulfuric acid acidic copper electrolytic solution" are not particularly limited, but it is generally preferable that the copper concentration is in the range of 70 g / L to 90 g / L and the free sulfuric acid concentration is in the range of 100 g / L to 200 g / L to be.

The polyethyleneimine used in the electrolytic copper foil manufacturing method according to the present application has a molecular weight of 10000 to 70000 (containing a primary amine, a secondary amine and a tertiary amine) (trademark of Nippon Shokubai Co., Ltd. Product number SP-200, P-1000), etc.). The polyethyleneimine is added to the sulfuric acid-acidic copper electrolytic solution used in the production of the electrolytic copper foil. The acidic copper sulfate electrolyte to which polyethyleneimine is added is suitable for the production of an electrolytic copper foil which requires a long continuous electrolysis because its solution life is long and its solution stability during electrolysis is excellent. Electrolytic copper foil obtained by using a sulfuric acid-acidic copper electrolytic solution to which polyethyleneimine is added is preferable because it has a tendency to stabilize high temperature heat resistance properties. When the molecular weight of the polyethyleneimine is less than 10000, even if the amount of addition of the polyethyleneimine is increased, sufficient electrothermal resistance can not be imparted to the resulting electrolytic copper foil. On the other hand, even if a polyethyleneimine having a molecular weight of more than 70,000 is used, fluctuation of high-temperature heat-resistant properties of the resultant electrolytic copper foil tends to increase, which is not preferable. The structural formula of this polyethyleneimine is shown in the following formula (1).

[Chemical Formula 1]

The polyethyleneimine preferably has a concentration of 20 mg / L to 100 mg / L in the sulfuric acidic copper electrolytic solution. When the concentration of the polyethyleneimine is less than 20 mg / L, the obtained electrolytic copper foil can not be provided with sufficient high-temperature heat resistance characteristics. On the other hand, when the concentration of the polyethyleneimine exceeds 100 mg / L, the content of the above-mentioned minor component contained in the electrolytic copper foil tends to be excessive, and even if the tensile strength and the 0.2% proof stress as the electrolytic copper foil are improved, Which is undesirable.

It is preferable that the sulfuric acidic copper electrolytic solution used in the electrolytic copper foil manufacturing method according to the present application has a chlorine concentration of 0.5 mg / L to 2.5 mg / L. When the chlorine concentration is less than 0.5 mg / L, the steady state tensile strength is high, but it is not preferable because the high temperature heat resistance characteristic is remarkably lowered. On the other hand, if the chlorine concentration exceeds 2.5 mg / L, both the steady state tensile strength and the high-temperature heat resistance characteristics are deteriorated.

As other production conditions, electrolysis at a current density of 40 A / dm ² to 90 A / dm ² and a liquid temperature of 40 ° C to 55 ° C at the time of production of the electrolytic copper foil is preferable. If the electrolysis conditions are within the range, stable electrolysis is possible and electrolytic copper foil of high quality can be produced.

Form of the surface-treated copper foil: The surface-treated copper foil according to the present application is characterized by being obtained using the electrolytic copper foil according to the present application. The surface treatment as used herein refers to a treatment for improving chemical adhesion such as roughening treatment, rust-preventive treatment, and silane coupling agent treatment. There is no particular limitation on the method and kind of the roughening treatment at this time. For example, a method of attaching fine particles of copper, copper alloy, nickel, nickel alloy or the like to the surface of the copper foil, a method of forming a fine irregular shape by etching the surface of the copper foil, or the like can be employed.

As the rust-preventive treatment, any rust-preventive treatment may be used as long as the effect of rust-inhibiting treatment can be obtained by applying, adhering, or precipitating on the surface of the electrolytic copper foil. For example, it is possible to use organic rust inhibiting treatment (treatment with benzotriazole, imidazole or the like), and inorganic rust inhibitive treatment (treatment with zinc, zinc alloy, nickel alloy, etc.). In the case of this anti-corrosive treatment, it is also preferable to perform the anti-corrosive treatment described in the specification of the international application (International Publication No. WO2012 / 070589, International Publication No. WO2012 / 070591) filed by the applicant of the present application. When the rust-preventive treatment described above is adopted, it is possible to further improve the high-temperature heat-resistant characteristics exhibited in electrolytic copper foil. There is also no particular limitation on the chemical adhesion improving treatment such as the treatment with a silane coupling agent, and depending on the nature of the constituent resin of the base material to which the surface-treated copper foil of the present application is applied and the properties of the negative electrode active material and binder of the lithium ion secondary battery , And a known silane coupling agent.

Hereinafter, examples and comparative examples are shown, and good high-temperature heat resistance characteristics of the electrolytic copper foil of the present application will be described while contrasting them.

Example

[Example 1]

In Example 1, a sulfuric acid-acidic copper electrolytic solution having a copper concentration of 80 g / L, a free sulfuric acid concentration of 140 g / L, a polyethyleneimine concentration of 55 mg / L and a chlorine concentration of 2.2 mg / 70 A / dm < ² > and a liquid temperature of 50 DEG C to obtain an electrolytic copper foil having a thickness of 15 mu m. The evaluation results of this electrolytic copper foil are shown in Tables 2 to 4 so as to be in contrast to the comparative example.

[Examples 2 to 10]

The composition of each of the sulfuric acidic acidic copper electrolytic solution is shown in Table 1 in the same manner as in Example 2 to Example 10 because the composition of the sulfuric acidic acidic copper electrolytic solution is different from that of Example 1. [ The evaluation results of the electrolytic copper foils obtained in the respective Examples are shown in Tables 2 to 4 so as to be in contrast to the comparative examples.

Comparative Example

[Comparative Examples 1 to 7]

In Comparative Examples 1 to 7, the copper sulfate concentration and the sulfuric acid concentration were the same as those in Example 1, and the sulfuric acid acidic copper electrolytic solution having the composition shown in Table 1 was used. Electrolysis was carried out under the same conditions as in Example 1, Of electrolytic copper foil.

[Comparative Example 8]

In Comparative Example 8, the electrolytic copper foil having a thickness of 15 탆 was obtained by electrolysis using the sulfuric acid-acidic copper electrolytic solution described in Example 6 of Patent Document 1 at a current density of 40 A / dm ² and a solution temperature of 50 캜.

[Comparative Example 9]

In Comparative Example 9, the electrolytic copper foil having a thickness of 15 탆 was obtained by electrolysis using the sulfuric acid-acidic copper electrolyte described in Example 5 of Patent Document 3 at a current density of 40 A / dm ² and a liquid temperature of 40 캜.

[Comparative Example 10]

In Comparative Example 10, a sulfuric acid-acidic copper electrolytic solution for obtaining the sample 8 described in the example of Patent Document 6 described above was used and electrolytic was carried out under conditions of a current density of 60 A / dm ² and a solution temperature of 50 캜, ≪ / RTI >

[Comparative Example 11]

In Comparative Example 11, a sulfuric acid-acidic copper electrolytic solution for obtaining Sample 1 described in the example of Patent Document 8 described above was used and electrolytic was carried out under conditions of a solution temperature of 50 캜 and a current density of 75 A / dm ² , Copper foil was obtained.

[Comparative Example 12]

In Comparative Example 12, a sulfuric acid-acidic copper electrolytic solution for obtaining the sample 4 described in the example of Patent Document 8 described above was used and electrolytic was carried out under conditions of a solution temperature of 50 캜 and a current density of 75 A / dm ² , Copper foil was obtained.

[Comparative Example 13]

In Comparative Example 13, an electrolytic copper foil having a thickness of 15 占 퐉 used for the production of a VLP copper foil manufactured by Mitsui Kinzoku Co., Ltd. was used.

[Evaluation method, etc.]

Microcontent content in electrolytic copper foil: The content of O and the content of N in the electrolytic copper foil were measured using EMGA-620 manufactured by Horiba Seisakusho Co., Ltd. after oxides of copper foil surface were removed with dilute nitric acid. At this time, the O content was measured by "Inert gas fusion-peculiar dispersion type infrared absorption method (NDIR)" and the N content was measured by "Inert gas fusion-heat conduction method (TCD)". The C content and the S content in the electrolytic copper foil were determined by removing the oxide on the surface of the copper foil with dilute nitric acid and then measuring the amount of C and S in the " high frequency heating-infrared absorption method in oxygen stream ", using EMIA-920V manufactured by Horiba Seisakusho Co., .

The Cl content in the electrolytic copper foil was measured by silver bromide co-precipitation-ion chromatography. A concrete measurement method is as follows. The electrolytic copper foil is dissolved by heating in nitric acid, and a certain amount of silver nitrate is added. Then, a predetermined amount of the KBr solution is added, and chloride ions are coprecipitated together with silver bromide. Thereafter, after standing in a dark place for 15 minutes, the precipitate is separated by filtration, and the precipitate is washed. Thereafter, the precipitate was placed in a beaker, the precipitate was dissolved with thiourea solution, and the solution was allowed to stand in a dark place overnight. Thereafter, this solution was diluted, fixed, and the chloride ion concentration was measured by ion chromatography using the ICS-2000 electrical conductivity detector (eluent KOH, column AS-20) manufactured by Dionex Inc. , And the Cl content was calculated.

Tensile strength, 0.2% proof stress and elongation: The electrolytic copper foil obtained in Examples and Comparative Examples was cut into a rectangle having a length of 10 cm and a width of 1 cm, and used as a sample for measurement of tensile strength and the like. Then, tensile strength, 0.2% proof stress and elongation were measured using an Instron tensile tester.

Heating conditions of sample: A rectangular sample used for measurement of tensile strength, etc. was heated in a heating oven in an inert gas atmosphere at each temperature of 300 DEG C x 1 hour, 350 DEG C x 1 hour, and 350 DEG C x 4 hours, The furnace was cooled in the furnace to the vicinity of room temperature to obtain a sample after heating. Using this rectangular sample after the heating, tensile strength, 0.2% proof stress and elongation were measured in the same manner as described above.

[Contrast of Examples and Comparative Examples]

Table 1 shows the comparison of the mixing ratio of the additive contained in the sulfuric acid-acidic copper electrolytic solution of the examples and the comparative example when the contrasts of the examples and the comparative examples are performed.

As can be seen from the results shown in Table 1, the copper sulfate electrolyte suitable for the electrolytic copper foil manufacturing method according to the present application is a copper electrolytic solution having a concentration of 20 mg / L to 100 mg / L and a molecular weight of 10000 to 70000 Polyethyleneimine "and" a chlorine concentration of 0.5 mg / L to 2.5 mg / L ". On the contrary, in the comparative example, it is clear that the sulfuric acid-containing copper electrolytic solution which does not satisfy the additive requirement of the sulfuric acidic copper electrolytic solution suitable for the method of manufacturing electrolytic copper foil according to the present application or contains completely different additives Do. The content of trace components contained in each electrolytic copper foil obtained in Examples and Comparative Examples is shown in Table 2 below.

From the Table 2, it can be understood that the electrolytic copper foil according to the examples and the comparative example is prepared in view of the content of trace components contained therein. From Table 2, it can be understood that all of the electrolytic copper foils according to the examples satisfy the conditions of the minor component content (C content, N content, O content, S content, Cl content) and conditions of trace component composition ratios. On the other hand, it was found that the electrolytic copper foil of the comparative example did not satisfy any of the conditions of the content of the minor component or the content of the minor component.

In Comparative Example 1 of Table 2, the condition of the trace component content was not satisfied, and the condition of the chlorine component ratio was satisfied. In Comparative Example 3 and Comparative Example 6, it was found that the condition of the trace component content was satisfied, but the condition of the chlorine component ratio was not satisfied. The electrolytic copper foils obtained in these Comparative Examples are not provided with good high temperature heat resistance characteristics as described later. As can be understood from this, it was found that electrolytic copper foil having good high-temperature heat resistance properties can not be obtained unless both of the compositional ratio of trace components excluding chlorine contained in the electrolytic copper foil and the chlorine component ratio condition are satisfied.

It was also found that the difference between the electrolytic copper foils of Examples and Comparative Examples becomes clearer when the ratio of trace components of nitrogen and chlorine as trace components is taken as a reference based on the total content of nitrogen, sulfur and chlorine. The ratio of the trace amount of nitrogen at this time is a value of {N / (N + S + Cl)} × 100, and the ratio of the trace amount of chlorine is {Cl / (N + S + Cl)} × 100. The trace component ratios of nitrogen and chlorine contained in each electrolytic copper foil obtained in Examples and Comparative Examples are shown in Table 3 below.

From the ratio of trace components in the electrolytic copper foil shown in Table 3, the following can be understood. From the viewpoint of the value of {N / (N + S + Cl)} x 100, the examples are 20.3 mass% to 45.8 mass% and the comparative example is 6.2 mass% to 27.3 mass% It can be understood that the embodiment tends to show a large value. All the embodiments satisfy the relationship of {N / (N + S + Cl)} x 100? 20 mass%, but in the case of the comparative example, many of those that do not satisfy this relationship can be seen. Therefore, in the case of an electrolytic copper foil having good high-temperature heat resistance characteristics, it can be said that the trace component preferably satisfies the relationship of {N / (N + S + Cl)} x 100? 20 mass%.

Next, the values of {Cl / (N + S + Cl)} x 100 shown in Table 3 were 3.0% by mass to 15.9% by mass in Examples and 7.1% by mass to 86.2% by mass in Comparative Examples, Although there is a range, it can be understood that the comparative example tends to show a large value. All the examples satisfy the relationship of {Cl / (N + S + Cl)} x 100? 20 mass%, but in the case of the comparative example, many of them do not satisfy this relation. The electrolytic copper foil of Comparative Example 1, Comparative Example 2 and Comparative Example 7, in which the chlorine concentration was lower than the upper limit value or lower than the lower limit value of the composition range of the copper sulfate acid solution suitable for the present application, And does not have characteristics. Therefore, when the electrolytic copper foil satisfies the above-mentioned " {Cl / (C + N + O + S + Cl) Further, it is the most stable that the value of "{Cl / (N + S + Cl)} × 100" is in the appropriate range, and it can be understood that the condition has good high temperature heat resistance characteristics.

Hereinafter, the physical properties of the electrolytic copper foil according to the examples and the electrolytic copper foil according to the comparative example will be described. These physical properties are shown in Table 4 so as to facilitate contrast in Examples and Comparative Examples.

The steady state tensile strength and 0.2% proof stress shown in Table 4 will be described. In the case of the electrolytic copper foil according to the example, the steady state tensile strength is from 610 MPa to 774 MPa, and the steady state 0.2% proof strength is from 442 MPa to 574 MPa. On the other hand, in the comparative example, the steady state tensile strength is 395 MPa to 791 MPa and the steady state 0.2% proof stress is 358 MPa to 501 MPa. Therefore, it can be understood that the electrolytic copper foil according to the example satisfies the condition that the " steady state tensile strength is 600 MPa or more ".

Next, the tensile strength and the 0.2% proof stress after heating at 300 ° C for 1 hour shown in Table 4 will be described. In the case of the electrolytic copper foil of the examples, the tensile strength after heating at 300 占 폚 for 1 hour shows a value of 502 MPa to 613 MPa, and the 0.2% proof stress after heating at 300 占 폚 for 1 hour has a value of 384 MPa to 460 MPa. In contrast, in the case of the comparative example, the tensile strength after heating at 300 占 폚 for 1 hour shows a value of 162 MPa to 538 MPa, and the 0.2% proof stress after heating at 300 占 폚 for 1 hour has a value of 118 MPa to 396 MPa. Therefore, even after heating at 300 ° C for 1 hour, it was found that the values of Examples were higher than those of Comparative Examples. For example, in the comparative example, Comparative Example 10, which exhibited the highest physical properties in a steady state, showed that the tensile strength after heating at 300 占 폚 for one hour drastically decreased to 199 MPa, and the 0.2% , It can be understood that it can not be said to be an electrolytic copper foil showing good high-temperature heat resistance characteristics because it is abruptly lowered to 179 MPa. However, in more detail, in the case of Comparative Example 12, the "high tensile strength after heating for one hour at 300 ° C × 500 MPa or higher" and "high temperature heat resistance equivalent to the embodiment with 0.2% proof stress after heating for one hour at 300 ° C. × 380 MPa or more" .

However, the tensile strength and the 0.2% proof stress after heating at 350 占 폚 for 1 hour shown in Table 4 show that the electrolytic copper foil of the examples has a significantly higher heat resistance than the comparative example. In the case of the electrolytic copper foil of the examples, the tensile strength after heating at 350 占 폚 for 1 hour is 473 MPa to 583 MPa, and the 0.2% proof stress after heating at 350 占 폚 for 1 hour is 371 MPa to 446 MPa. In contrast, in the case of the comparative example, the tensile strength after heating at 350 占 폚 for 1 hour shows a value of 71 MPa to 455 MPa, and the 0.2% proof stress after heating at 350 占 폚 for 1 hour has a value of 64 MPa to 359 MPa. Therefore, it was found that, after heating at 350 ° C for 1 hour, both the tensile strength and the 0.2% proof stress were clearly higher in the examples than in the comparative examples. That is, it can be understood that the electrolytic copper foil according to the embodiment has a superiority to the conventional electrolytic copper foil when heated at a higher temperature than the comparative example. Comparative Example 4, Comparative Example 5, Comparative Example 11 and Comparative Example 12 in which the tensile strength and the 0.2% proof stress after heating at 300 ° C for 1 hour had the same properties as those of the Examples show that tensile strength Is 455 MPa or less, and the 0.2% proof stress is reduced to 359 Pa or less. That is, in the case of the comparative example, it is clear that the condition of "tensile strength after heating at 350 ° C for 1 hour is not more than 470 MPa" is not satisfied.

Hereinafter, a tensile strength and 0.2% proof stress after heating at 350 ° C for 4 hours as a case in which a larger amount of heat is applied will be briefly described. In this heating test, the electrolytic copper foils of Examples 8 and 10 were used. As a result, in the case of the electrolytic copper foil of Example 8, the tensile strength after heating at 350 ° C for 4 hours was 533 MPa, the 0.2% proof stress after heating at 350 ° C for 4 hours was 416 MPa, the elongation percentage after heating at 350 ° C for 4 hours Respectively. In the case of the electrolytic copper foil of Example 10, the tensile strength after heating at 350 占 폚 for 4 hours was 520 MPa, the 0.2% proof stress after heating at 350 占 폚 for 4 hours was 423 MPa, and the elongation percentage after heating at 350 占 폚 for 4 hours was 1.7% Respectively. These values are very good values considering that they are values after a very severe heating. Thus, in the case of the electrolytic copper foil according to the present application, it is possible to satisfy the two conditions of "tensile strength after heating at 350 占 폚 for 4 hours is 470 MPa or more" and "0.2% proof stress after heating at 350 占 폚 for 4 hours is 370 MPa or more".

The electrodeposited copper foil of the present application described above has physical properties of "normal state tensile strength of 600 MPa or more" and "tensile strength after heating at 350 ° C for 1 hour" of 470 MPa or more. Therefore, even in the case of a thin electrolytic copper foil, occurrence of wrinkles is small and good handling characteristics are provided. Such an electrolytic copper foil is a surface-treated copper foil having good high-temperature heat-resisting properties even under a high temperature load and subjected to various surface treatments as required, and can be suitably used in fields such as printed wiring boards and lithium ion secondary batteries. In addition, the electrolytic copper foil manufacturing method according to the present application is preferable in that it requires only the replacement of the sulfuric acid-acidic copper electrolytic solution of the electrolytic copper foil and the conventional electrolytic copper foil manufacturing facility as it is, thereby making the new facility investment unnecessary.

Claims (6)

Wherein the tensile strength after heating at 350 占 폚 for 1 hour is 470 MPa or more in a steady state tensile strength of 600 MPa or more. The electrolytic copper foil according to claim 1, wherein the 0.2% proof strength after heating at 350 ° C for 1 hour is not less than 370 MPa. The electrolytic copper foil according to claim 1 or 2, wherein the steady state elongation is 2.5% or more. 4. The electrolytic copper foil according to any one of claims 1 to 3, wherein the electrolytic copper foil has a C content of 100 占 퐂 / g to 450 占 퐂 / g, an N content of 50 占 퐂 / g to 620 占 퐂 / g, an O content of 400 占 퐂 / g to 3200 μg / g, an S content of 110 μg / g to 720 μg / g and a Cl content of 20 μg / g to 115 μg / g,
And an electrolytic copper foil satisfying the relationship of {Cl / (C + N + O + S + Cl)} x 100? 5 mass%. A method for producing an electrolytic copper foil as set forth in any one of claims 1 to 4,
Characterized in that a copper sulfate electrolytic solution is used which contains a polyethyleneimine having a concentration of 20 mg / L to 100 mg / L and a molecular weight of 10000 to 70000 and a copper sulfate acid electrolytic solution having a chlorine concentration of 0.5 mg / L to 2.5 mg / A method of manufacturing a copper foil. A surface-treated copper foil obtained by using the electrolytic copper foil according to any one of claims 1 to 5.