Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D1/00—Electroforming
  • C25D1/04—Wires; Strips; Foils
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/38—Electroplating: Baths therefor from solutions of copper
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D7/00—Electroplating characterised by the article coated
  • C25D7/06—Wires; Strips; Foils
  • C25D7/0614—Strips or foils

Definitions

• the present application relates to an electrolytic copper foil, a method for producing the electrolytic copper foil, and a surface-treated copper foil obtained using the electrolytic copper foil.
• the present invention relates to an electrolytic copper foil having excellent high temperature heat resistance when subjected to high temperature heating.
• Electrolytic copper foil is widely used in various fields such as the printed wiring board field and the negative electrode current collector of lithium ion secondary batteries. And in printed wiring boards, a very high temperature exceeding 250 ° C may be adopted as the processing temperature for bonding the copper foil and the insulating layer constituent material, and the electrolytic copper foil subjected to a high temperature load softens. Since the physical strength is reduced, various problems have occurred. Moreover, when using an electrolytic copper foil as a negative electrode current collector of a lithium ion secondary battery, a high temperature of about 300 ° C. is applied when a mixture layer containing a negative electrode active material is formed on the surface of the electrolytic copper foil. Sometimes.
• electrolytic copper foil used for the negative electrode current collector If the electrolytic copper foil used for the negative electrode current collector is softened at this time, the resistance to expansion / contraction during charging / discharging is reduced, which may shorten the life of the lithium ion secondary battery. For this reason, research has been conducted on electrolytic copper foils that are excellent in high temperature heat resistance when subjected to high temperature heating.
• Patent Document 1 for the purpose of providing an electrolytic copper foil that maintains high strength even after storage for a long time, has high strength after heating, and is excellent in electrical conductivity, “(A) a dithiocarbamic acid derivative or A salt thereof, (B) thiourea, (C) a water-soluble sulfur compound having a mercapto group or a derivative thereof, or a salt thereof, (D) polyalkylene glycol and (E) an acidic copper plating containing chlorine ions as additives Electrolytic copper foil is produced by electrolyzing the liquid.
• Patent Document 2 for the purpose of providing an electrolytic copper foil that has a low rough surface suitable as an electrolytic copper foil material used in the Tape Automated Bonding method, has high tensile strength, and does not cause peeling of tin plating.
• An electrolytic copper foil in which a sulfuric acid-copper sulfate aqueous solution is used as an electrolytic solution, and an insoluble anode made of titanium coated with a platinum group element or an oxide thereof and a titanium cathode drum facing the anode are passed through a direct current between the electrodes
• a non-ionic water-soluble polymer, a sulfonate of an active organic sulfur compound, a thiourea compound, and a chlorine ion are present in the electrolytic solution, so that the rough surface roughness is 2.0 ⁇ m or less.
• a crystal having an orientation index of 5.0 or more determined from the relative intensity of 220 copper diffraction lines measured by X-ray diffraction on the rough surface side A weave, tensile strength after heating 180 ° C. ⁇ 1 hour to obtain an electrolytic copper foil is 500 MPa. "It has been disclosed.
• Patent Document 3 provides a low-roughened surface electrolytic copper foil having a low-roughened rough surface, a low rate of decrease in tensile strength with time or heat treatment, and an excellent elongation at high temperature, and a method for producing the same.
• the purpose of this study was to make the electrolytic copper foil coarse by adding five additives of hydroxyethyl cellulose, polyethyleneimine, acetylene glycol, sulfonates of active organic sulfur compounds and chloride ions to an electrolytic solution composed of sulfuric acid-copper sulfate aqueous solution.
• the surface roughness Rz is 2.5 ⁇ m ⁇ m or less, the tensile strength at 25 ° C.
• the copper foil is not softened and maintained at a high tensile strength even when it is stored at room temperature from the completion of copper foil production to the next manufacturing process or by heat treatment at about 200 to 300 ° C. in the next process.
• a high tensile strength electrolysis having a tensile strength of 400 N / mm 2 or more measured at 25 ° C. after the completion of copper foil production and after the characteristics of the copper foil are stabilized "Copper foil.”
• the copper foil is heated at 300 ° C. for 1 hour.
• High tensile strength electrolytic copper foil whose tensile strength measured at 25 ° C. after the heat treatment is 400 N / mm 2 or more is disclosed.
• Patent Document 5 discloses an electrolytic copper for a negative electrode of a lithium ion secondary battery that can produce a lithium ion secondary battery that has a long life without deterioration in capacity retention even when a charge / discharge cycle is repeated, and whose negative electrode current collector is not deformed.
• the 0.2% proof stress after heat treatment at 200 to 400 ° C. is 250 N / mm 2 or more
• the elongation is 2.5% or more
• the active material layer of the electrolytic copper foil is The surface to be provided is subjected to rust prevention treatment or roughening treatment and rust prevention treatment
• the present invention discloses an electrode for a lithium ion secondary battery using the electrolytic copper foil as a current collector. Yes. That is, an electrolytic copper foil is used as the negative electrode current collector of the lithium ion secondary battery, and “0.2% proof stress” after heating the electrolytic copper foil at 240 ° C. for 10 minutes is defined.
• Patent Document 6 for the purpose of providing a high-strength electrolytic copper foil that is an electrolytic copper foil for forming a fine pitch circuit and that can be used in place of a Corson alloy foil, “obtained by electrolyzing a copper electrolyte”
• the electrolytic copper foil contains 110 ppm to 400 ppm of sulfur, 150 ppm to 650 ppm of chlorine, has a conductivity of 48% IACS or more, and a normal tensile strength value of 70 kgf / mm 2 or more.
• a featured electrolytic copper foil is disclosed.
• Patent Document 7 for the purpose of providing an electrolytic copper foil having a low profile surface equivalent to that of a conventional low profile electrolytic copper foil and having extremely high mechanical strength, and a method for producing the same, “copper An electrolytic copper foil in which the precipitated crystal particles are fine and the variation in particle diameter is as small as ever, having a low profile, glossy surface, and a normal tensile strength value of 70 kgf / mm 2 An electrolytic copper foil having an extremely large mechanical strength of ⁇ 100 kgf / mm 2 and having a tensile strength value of 85% or more of the normal tensile strength value even after heating (180 ° C. ⁇ 60 minutes). ” It is disclosed.
• Patent Document 8 discloses that for the purpose of providing an electrolytic copper foil that exhibits stable characteristics even when the chlorine content fluctuates, “an electrolytic copper foil obtained by electrolyzing a copper electrolyte, Adopting an electrolytic copper foil characterized in that the iodine content in the foil is 0.003% by mass or more, more preferably the iodine content is in the range of 0.003% to 0.03% by mass. is doing.
• the electrolytic copper foil normally tensile strength of 48kgf / mm 2 ⁇ 72kgf / mm 2, the tensile strength after the 350 ° C. ⁇ 60 min heating is that 27.5kgf / mm 2 ⁇ 46.3kgf / mm 2 It is disclosed that it exhibits physical characteristics and is suitable for use as a negative electrode current collector of a lithium ion secondary battery.
• the electrolytic copper foil used for the negative electrode current collector of the lithium ion secondary battery prevents deformation of the negative electrode current collector that occurs during charging and discharging.
• an alloy-based negative electrode active material having a large volume change accompanying charge / discharge may be used.
• a mixture layer is formed using a strong binder to prevent the active material from collapsing due to a large volume change during charge and discharge.
• high temperature of 300 degreeC or more is loaded. Therefore, the electrolytic copper foil used for the negative electrode current collector cannot extend the life of the lithium ion secondary battery unless it has high-temperature heat resistance characteristics that can maintain high strength even after being heated to 300 ° C. or higher.
• the electrolytic copper foil of the above-mentioned patent document 4 there is a possibility of having sufficient high temperature heat resistance.
• the electrolytic copper foil in the same document has a high-temperature heat resistance characteristic of “the tensile strength after heat treatment at 300 ° C. for 1 hour is 400 N / mm 2 or more”.
• the tensile strength (tensile strength) after heating at 300 ° C. for 1 hour 72 hours after the completion of the foil is in the range of 430 MPa to 500 MPa, and no tensile strength exceeding 500 MPa is obtained.
• the recent electrolytic copper foil is not limited to the field of printed wiring boards, and the thinning is remarkable. As the electrolytic copper foil becomes thinner, wrinkles are more likely to occur during handling. From the viewpoint of preventing the occurrence of wrinkles during handling, it is preferable to have high physical properties not only after high-temperature heating of the electrolytic copper foil but also in a normal state.
• an object of the present application is to provide an electrolytic copper foil that has good high-temperature heat resistance characteristics and can be used for a negative electrode current collector of a printed wiring board and a lithium ion secondary battery.
• the inventors have come up with an electrolytic copper foil that is superior in both “normal physical properties” and “physical properties after high-temperature heating” as compared with conventional electrolytic copper foils. And it turned out that the electrolytic copper foil which concerns on this application is suitable for the negative electrode collector use of a lithium ion secondary battery.
• the outline of the invention related to the present application will be described below.
• Electrolytic copper foil The electrolytic copper foil according to the present application has a normal tensile strength of 600 MPa or more and a tensile strength after heating at 350 ° C. for 1 hour is 470 MPa or more.
• the electrolytic copper foil according to the present application has high physical properties such that 0.2% proof stress after heating at 350 ° C. for 1 hour is 370 MPa or more.
• the electrolytic copper foil according to the present application has a normal elongation of 2.5% or more, and has an elongation that does not hinder practical use.
• the electrolytic copper foil according to the present application has, as trace components, a C content of 100 ⁇ g / g to 450 ⁇ g / g, an N content of 50 ⁇ g / g to 620 ⁇ g / g, an O content of 400 ⁇ g / g to 3200 ⁇ g / g, S It is stable that the content is in the range of 110 ⁇ g / g to 720 ⁇ g / g, the Cl content is in the range of 20 ⁇ g / g to 115 ⁇ g / g, and satisfies the relationship of ⁇ Cl / (C + N + O + S + Cl) ⁇ ⁇ 100 ⁇ 5 mass%. It is preferable from the viewpoint of exhibiting the high temperature heat resistance characteristics.
• the manufacturing method of the electrolytic copper foil according to the present application is the above-described manufacturing method of the electrolytic copper foil, and has a molecular weight of 10,000 to 70,000 as a copper electrolyte at a concentration of 20 mg / L to 100 mg / L. And an acidic copper electrolyte having a chlorine concentration of 0.5 mg / L to 2.5 mg / L.
• the surface-treated copper foil according to the present application is obtained by using the above-described electrolytic copper foil.
• the electrolytic copper foil according to the present application has physical properties of “normal 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 according to the present application is excellent in both “normal physical characteristics” and “physical characteristics after high-temperature heating”. Therefore, even with a thin electrolytic copper foil, the generation of wrinkles is small, and good handling characteristics are provided. In addition, even when such an electrolytic copper foil is used as a negative electrode current collector of a lithium ion secondary battery, there is little decrease in tensile strength when the negative electrode active material is carried, so when performing charging / discharging. The resistance to expansion / contraction of the battery is high, and the battery life can be extended.
• this electrolytic copper foil can be made into surface-treated copper foil that has been subjected to roughening treatment, rust prevention treatment, etc. according to applications, and is widely used in the fields of printed wiring boards, lithium ion secondary batteries, etc. Is possible.
• the electrolytic copper foil according to the present application is a copper foil that has not been subjected to a surface treatment such as a rust-proofing treatment or a roughening treatment, and the thickness thereof is not particularly limited.
• a surface treatment such as a rust-proofing treatment or a roughening treatment
• the electrolytic copper foil which concerns on this application described below is specified by the physical characteristic. The value of this physical property shows substantially the same value between “electrolytic copper foil” and “surface-treated copper foil” subjected to the surface treatment described later.
• the electrolytic copper foil according to the present application is characterized in that “normal tensile strength is 600 MPa or more” and simultaneously has physical properties of “tensile strength after heating at 350 ° C. ⁇ 1 hour” is 470 MPa or more.
• an electrolytic copper foil having “normal tensile strength of 600 MPa or more” also exists in the past.
• the electrolytic copper foil having the physical property of “normal tensile strength of 600 MPa or more” Is used.
• the electrolytic copper foil has a “normal tensile strength of 600 MPa or more”, even an electrolytic copper foil having a thickness of 9 ⁇ m or less is less likely to be wrinkled during handling, and workability is improved.
• an electrolytic copper foil having a physical property of “tensile strength after heating at 350 ° C. ⁇ 1 hour is 470 MPa or more” is used as a negative electrode current collector of a lithium ion secondary battery, high quality with a long battery life is obtained. It is preferable because a lithium ion secondary battery can be provided.
• the electrolytic copper foil When an electrolytic copper foil having such physical properties is used for the negative electrode current collector, the electrolytic copper foil is supported even when the polymerization reaction of the binder is performed at a temperature of 300 ° C. or higher in order to carry the alloy-based negative electrode active material. This is because a decrease in the strength of the sheet is reduced. Furthermore, regarding “tensile strength after heating at 350 ° C. ⁇ 1 hour”, “the tensile strength after heating at 350 ° C. ⁇ 1 hour exceeds 500 MPa” is more preferable. This is because even if the heat treatment time is further prolonged, a high tensile strength can be stably provided. Moreover, if it is an electrolytic copper foil provided with such a high temperature heat-resistant characteristic, the design which makes a thin negative electrode current collector is also possible.
• the electrolytic copper foil according to the present application has a “0.2% proof stress after heating at 350 ° C. for 1 hour” of 370 MPa or more.
• a copper foil composed mainly of copper which is a non-ferrous material
• the "0.2% yield strength” and the above-mentioned "tensile strength” do not show a complete correlation, but if the 0.2% yield strength value is high, the tensile strength tends to increase. is there. If the “0.2% proof stress after heating at 350 ° C.
• 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 indicators, and thus the high temperature heat resistance against heating. Evaluation of characteristics can be ensured. Below, the high temperature heat resistance characteristic which the electrolytic copper foil which concerns on this application shows when a severer high temperature load is added is described.
• the 0.2% yield strength after a 350 degreeC x 1 hour heating is 410 Mpa or more. This is because the above-described tensile strength after heating at 350 ° C. for 1 hour exceeds 500 MPa.
• the electrolytic copper foil according to the present application preferably has a high tensile strength of “the tensile strength after heating at 350 ° C. ⁇ 4 hours is 470 MPa or more”.
• the electrolytic copper foil which concerns on this application it is more preferable to provide the high tensile strength of "the tensile strength after 350 degreeC x 4 hours heating is 500 Mpa or more.” Moreover, it is preferable that the electrolytic copper foil which concerns on this application is provided with the high 0.2% yield strength of "the 0.2% yield strength after a 350 degreeC x 4 hour heating is 370 Mpa or more.” And in the case of the electrolytic copper foil which concerns on this application, it is more preferable to provide the high 0.2% yield strength of "the 0.2% yield strength after heating at 350 degreeC x 4 hours is 410 Mpa or more.”
• the electrolytic copper foil according to the present application preferably has a normal elongation of 2.5% or more.
• the normal state elongation is less than 2.5%, the electrolytic copper foil may be broken when the mixture layer containing the negative electrode active material is formed on the surface of the electrolytic copper foil.
• 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. And it is preferable that the trace component of the electrolytic copper foil which concerns on this application satisfies the conditions shown below as content per mass of electrolytic copper foil.
• the C content is 100 ⁇ g / g to 450 ⁇ g / g (meaning “100 ⁇ g / g or more and 450 ⁇ g / g or less”, the same applies hereinafter)
• the N content is 50 ⁇ g / g to 620 ⁇ g / g
• the O content is Amount is 400 ⁇ g / g to 3200 ⁇ g / g
• S content is in the range of 110 ⁇ g / g to 720 ⁇ g / g
• Cl content is in the range of 20 ⁇ g / g to 115 ⁇ g / g
• the trace component ratio of N (nitrogen) contained in the electrolytic copper foil according to the present application satisfies the relationship of ⁇ N / (N + S + Cl) ⁇ ⁇ 100 ⁇ 20 mass%.
• this relationship is not satisfied, the recrystallization of the crystal structure of the electrolytic copper foil proceeds remarkably due to a high temperature load, and voids are likely to be generated in the crystal structure.
• heating at 350 ° C. for 1 hour or more there is a tendency that variations in tensile strength and 0.2% proof stress increase.
• ⁇ N / (N + S + Cl) ⁇ ⁇ 100 is the value of N content ( ⁇ g / g) contained in the electrolytic copper foil, and is the total amount of C content, S content, and Cl content contained in the electrolytic copper foil. Dividing by the value of ( ⁇ g / g) and multiplying by 100, it is a 100-percent fraction conversion value (mass%).
• the minor component ratio of Cl (chlorine) contained in the electrolytic copper foil according to the present application satisfies the relationship ⁇ Cl / (N + S + Cl) ⁇ ⁇ 100 ⁇ 20 mass%.
• this value exceeds 20% by mass, recrystallization of the crystal structure of the electrolytic copper foil proceeds remarkably due to a high temperature load, and voids are likely to be generated in the crystal structure.
• the amount is less than 3.0% by mass, the variation in tensile strength and 0.2% proof stress tends to increase.
• ⁇ Cl / (N + S + Cl) ⁇ ⁇ 100 is the value of the Cl content ( ⁇ g / g) contained in the electrolytic copper foil, the total amount of N content, S content, and Cl content contained in the electrolytic copper foil. Divided by the value of ( ⁇ g / g) and multiplied by 100, it is a 100% converted value (mass%).
• the manufacturing method of the electrolytic copper foil according to the present application is the above-described manufacturing method of the electrolytic copper foil, and as a copper electrolyte, a molecular weight of 10,000 to 100 mg / L to 100 mg / L. It is characterized by using an acidic copper sulfate electrolyte solution containing 70000 polyethyleneimine and having a chlorine concentration of 0.5 mg / L to 2.5 mg / L.
• the copper concentration and free sulfuric acid concentration of the “sulfuric acid copper electrolyte” are not particularly limited, but the copper concentration ranges from 70 g / L to 90 g / L and the free sulfuric acid concentration ranges from 100 g / L to 200 g / L. It is general that it is.
• the polyethyleneimine used in the method for producing an electrolytic copper foil according to the present application has a molecular weight of 10,000 to 70,000 including a primary amine, a secondary amine and a tertiary amine (trade name Epomin (product number SP- 200, P-1000)). And this polyethyleneimine is added and used for the sulfuric acid acidic copper electrolyte solution used for manufacture of electrolytic copper foil.
• the sulfuric acid acidic copper electrolyte to which polyethyleneimine is added has a long solution life and is excellent in solution stability during electrolysis, and is therefore suitable for the production of an electrolytic copper foil that requires long-term continuous electrolysis.
• an electrolytic copper foil obtained by using a sulfuric acid acidic copper electrolytic solution to which polyethyleneimine has been added is preferable because high temperature heat resistance tends to be stabilized.
• the molecular weight of this polyethyleneimine is less than 10,000, even if it increases the addition amount of a polyethyleneimine, it is unpreferable because sufficient high-temperature heat-resistant characteristics cannot be provided to the obtained electrolytic copper foil.
• polyethyleneimine having a molecular weight of more than 70000 is used, there is a tendency that variations in the high-temperature heat resistance characteristics of the obtained electrolytic copper foil tend to increase, which is not preferable.
• the structural formula of this polyethyleneimine is shown in the following chemical formula 1.
• the polyethyleneimine preferably has a concentration of 20 mg / L to 100 mg / L in the acidic copper sulfate electrolyte.
• concentration is less than 20 mg / L, it is not preferable because sufficient high temperature heat resistance characteristics cannot be imparted to the obtained electrolytic copper foil.
• the polyethyleneimine concentration exceeds 100 mg / L, the above-mentioned trace component content contained in the electrolytic copper foil tends to be excessive, and the tensile strength and 0.2% yield strength as the electrolytic copper foil are likely to be excessive. Even if improved, it is not preferred because it cures and the elongation decreases.
• the acidic copper sulfate electrolytic solution used in the method for producing an electrolytic copper foil according to the present application preferably has a chlorine concentration of 0.5 mg / L to 2.5 mg / L.
• the chlorine concentration is less than 0.5 mg / L, the normal tensile strength is high, but the high temperature heat resistance is remarkably deteriorated.
• the chlorine concentration exceeds 2.5 mg / L, both the normal tensile strength and the high temperature heat resistance are deteriorated.
• electrolysis in a current density range of 40 A / dm 2 to 90 A / dm 2 and a liquid temperature of 40 ° C. to 55 ° C. during the production of the electrolytic copper foil is suitable. If it is in the range of this electrolysis condition, stable electrolysis is possible and manufacture of high quality electrolytic copper foil is possible.
• the surface-treated copper foil according to the present application is obtained by using the electrolytic copper foil according to the present application described above.
• the surface treatment here means chemical adhesion improving treatment such as roughening treatment, rust prevention treatment, silane coupling agent treatment, and the like.
• any rust-proofing treatment may be used as long as the rust-proofing effect can be obtained by applying, adhering, or depositing on the surface of the electrolytic copper foil.
• organic rust prevention treatment treatment using benzotriazole, imidazole, etc.
• inorganic rust prevention treatment treatment using zinc, zinc alloy, nickel alloy, etc.
• Example 1 In Example 1, an acidic copper electrolyte having a copper concentration of 80 g / L, a free sulfuric acid concentration of 140 g / L, a molecular weight of 70000, a polyethyleneimine concentration of 55 mg / L, and a chlorine concentration of 2.2 mg / L, Electrolysis was performed under the conditions of a current density of 70 A / dm 2 and a liquid temperature of 50 ° C. to obtain an electrolytic copper foil having a thickness of 15 ⁇ m. The evaluation results of this electrolytic copper foil are shown in Tables 2 to 4 below so that they can be compared with the comparative examples.
• Example 2 to 10 Regarding Example 2 to Example 10, since the composition of Example 1 and the sulfuric acid copper electrolyte is different, the composition of each sulfuric acid copper electrolyte is summarized in Table 1. The evaluation results of the electrolytic copper foil obtained in each example are shown in Tables 2 to 4 later so that the comparison with the comparative example is possible.
• Comparative Examples 1 to 7 In Comparative Examples 1 to 7, the same copper concentration and free sulfuric acid concentration as in Example 1 were adopted, and an acidic copper electrolyte having the composition shown in Table 1 was used for electrolysis under the same conditions as in Example 1. Thus, an electrolytic copper foil having a thickness of 15 ⁇ m was obtained.
• Comparative Example 8 an electrolytic copper foil having a thickness of 15 ⁇ m was obtained by electrolysis under the conditions of a current density of 40 A / dm 2 and a liquid temperature of 50 ° C. using the acidic copper sulfate electrolytic solution described in Example 6 of Patent Document 1 described above. Got.
• Comparative Example 9 an electrolytic copper foil having a thickness of 15 ⁇ m was obtained by electrolysis under the conditions of a current density of 40 A / dm 2 and a liquid temperature of 40 ° C. using the acidic copper sulfate electrolyte described in Example 5 of Patent Document 3 above. Got.
• Comparative Example 10 an acidic copper sulfate electrolytic solution for obtaining Sample 8 described in the example of Patent Document 6 described above was used, and electrolysis was performed under the conditions of a current density of 60 A / dm 2 and a liquid temperature of 50 ° C. to obtain a thickness of 15 ⁇ m. The obtained electrolytic copper foil was obtained.
• Comparative Example 11 In Comparative Example 11, an acidic copper sulfate electrolytic solution for obtaining Sample 1 described in the example of Patent Document 8 described above was used, and electrolysis was performed under the conditions of a solution temperature of 50 ° C. and a current density of 75 A / dm 2. An electrolytic copper foil was obtained.
• Comparative Example 12 In Comparative Example 12, an acidic copper sulfate electrolytic solution for obtaining Sample 4 described in the example of Patent Document 8 described above was used, and electrolysis was performed under the conditions of a solution temperature of 50 ° C. and a current density of 75 A / dm 2 , and a thickness of 15 ⁇ m. An electrolytic copper foil was obtained.
• Comparative Example 13 an electrolytic copper foil having a thickness of 15 ⁇ m used for manufacturing a VLP copper foil manufactured by Mitsui Mining & Smelting Co., Ltd. was used.
• the Cl content in the electrolytic copper foil was measured by silver bromide coprecipitation-ion chromatography.
• the specific measurement method is as follows. The electrolytic copper foil is heated and dissolved with nitric acid, and a certain amount of silver nitrate is added. Next, a certain amount of KBr solution is added to coprecipitate chloride ions together with silver bromide. Then, after leaving still for 15 minutes in a dark place, a precipitate is separated by filtration and the precipitate is washed. Thereafter, the precipitate was put in a beaker, dissolved with a thiourea solution, and left overnight in a dark place. Thereafter, this solution was diluted and measured, and chloride ion concentration was measured by ion chromatography using a Dionex ICS-2000 conductivity detector, eluent KOH, column AS-20). The content was calculated.
• Tensile strength, 0.2% proof stress and elongation rate The electrolytic copper foil obtained in Examples and Comparative Examples was cut into strips having a length of 10 cm and a width of 1 cm, and this was used as a sample for measuring tensile strength and the like. It was. And the tensile strength, 0.2% yield strength, and elongation rate were measured using the Instron type
• Sample heating conditions A strip-shaped sample used for measurement of tensile strength, etc., is heated in an inert gas atmosphere at 300 ° C. ⁇ 1 hour, 350 ° C. ⁇ 1 hour, 350 ° C. ⁇ 4 hours. The sample was heated and cooled to near room temperature in the furnace to obtain a heated sample. Using this strip-shaped sample after heating, the tensile strength, 0.2% proof stress and elongation rate were measured in the same manner as described above.
• Table 1 shows the comparison between the examples and comparative examples so that the composition of the additive contained in the sulfuric acid acidic copper electrolyte of the examples and comparative examples can be easily compared.
• the sulfuric acid copper electrolyte suitable for the electrolytic copper foil manufacturing method according to the present application is “polyethylene having a molecular weight of 10,000 to 70,000 at a concentration of 20 mg / L to 100 mg / L. It satisfies the two requirements of “contains imine” and “contains a chlorine concentration of 0.5 mg / L to 2.5 mg / L”.
• the sulfuric acid copper electrolysis that does not satisfy the additive requirements of the acidic sulfuric acid copper electrolyte that is appropriate in the method for producing an electrolytic copper foil according to the present application or that contains a completely different additive It is clear that the liquid is used.
• the trace amount content contained in each electrolytic copper foil obtained by the Example and the comparative example is shown in the following Table 2.
• Comparative Example 1 in Table 2 does not satisfy the condition of the minor component content, and satisfies the condition of the chlorine component ratio. And when the comparative example 3 and the comparative example 6 are seen, although the conditions of trace component content are satisfy
• the trace component ratio in the electrolytic copper foil shown in Table 3 From the trace component ratio in the electrolytic copper foil shown in Table 3, the following can be understood. First, looking at the value of ⁇ N / (N + S + Cl) ⁇ ⁇ 100, the example is 20.3% by mass to 45.8% by mass, the comparative example is 6.2% by mass to 27.3% by mass, Although there are some overlapping ranges, it can be understood that the example tends to show a larger value. All of the examples satisfy the relationship ⁇ N / (N + S + Cl) ⁇ ⁇ 100 ⁇ 20% by mass. In the case of the comparative example, many of the examples do not satisfy this relationship. 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 ⁇ N / (N + S + Cl) ⁇ ⁇ 100 ⁇ 20 mass%.
• the electrolytic copper foils of Comparative Example 1, Comparative Example 2, and Comparative Example 7 in which the chlorine concentration is less than the lower limit value or exceeds the upper limit value of the composition range of the acidic sulfuric acid copper electrolyte suitable in the present application are as follows. As described later, it does not have good high temperature heat resistance. Accordingly, the electrolytic copper foil satisfies the above-mentioned values of “ ⁇ Cl / (C + N + O + S + Cl) ⁇ ⁇ 100” and “ ⁇ N / (N + S + Cl) ⁇ ⁇ 100”, and further, “ ⁇ Cl / (N + S + Cl) ⁇ ⁇ It can be understood that the value of “100” being in an appropriate range is the most stable condition with good high temperature heat resistance.
• the normal tensile strength and 0.2% proof stress shown in Table 4 will be described.
• the normal tensile strength is 610 MPa to 774 MPa
• the normal 0.2% proof stress is 442 MPa to 574 MPa.
• the normal tensile strength is 395 MPa to 791 MPa
• the normal 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 “normal tensile strength is 600 MPa or more”.
• the tensile strength and 0.2% proof stress after heating at 300 ° C. for 1 hour shown in Table 4 will be described.
• the tensile strength after heating at 300 ° C. ⁇ 1 hour is 502 MPa to 613 MPa
• the 0.2% proof stress after heating at 300 ° C. ⁇ 1 hour is 384 MPa to 460 MPa.
• the tensile strength after heating at 300 ° C. ⁇ 1 hour is 162 MPa to 538 MPa
• the 0.2% proof stress after heating at 300 ° C. ⁇ 1 hour is 118 MPa to 396 MPa. Therefore, even after heating at 300 ° C.
• Comparative Example 10 which showed the highest physical characteristics in the normal state, had a tensile strength after heating at 300 ° C. ⁇ 1 hour rapidly decreased to 199 MPa, and after heating at 300 ° C. ⁇ 1 hour. It can be understood that it cannot be said to be an electrolytic copper foil exhibiting good high-temperature heat-resistant characteristics because it is abruptly decreased to 179 MPa even when the 0.2% proof stress is observed.
• Comparative Example 12 “the tensile strength after heating at 300 ° C. ⁇ 1 hour is 500 MPa or more” and “the 0.2% proof stress after heating at 300 ° C. ⁇ 1 hour is 380 MPa or more.
• the tensile strength and 0.2% proof stress after heating at 350 ° C. for 1 hour shown in Table 4 it can be understood that the high-temperature heat resistance characteristics of the electrolytic copper foils of the examples are significantly superior to those of the comparative examples. .
• the tensile strength after heating at 350 ° C. for 1 hour is 473 MPa to 583 MPa
• the 0.2% proof stress after heating at 350 ° C. for 1 hour is 371 MPa to 446 MPa.
• the tensile strength after heating at 350 ° C. ⁇ 1 hour is 71 MPa to 455 MPa
• ⁇ 1 hour is 64 MPa to 359 MPa. Therefore, after heating at 350 ° C. for 1 hour, it can be seen that both the tensile strength and the 0.2% proof stress are clearly higher in the example than in the comparative example. That is, it can be understood that the electrolytic copper foil according to the example has a significant advantage over the conventional electrolytic copper foil when heated at a higher temperature than the comparative example. Even if it sees Comparative Example 4, Comparative Example 5, Comparative Example 11 and Comparative Example 12 in which the tensile strength and 0.2% proof stress after heating at 300 ° C. for 1 hour have the same characteristics as the Examples, 350 ° C.
• the tensile strength is reduced to 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 that “the tensile strength after heating at 350 ° C. ⁇ 1 hour is 470 MPa or more” is not satisfied.
• the tensile strength and 0.2% proof stress after heating at 350 ° C. for 4 hours will be briefly described.
• the electrolytic copper foils of Example 8 and Example 10 were used.
• the tensile strength after heating at 350 ° C. for 4 hours is 533 MPa
• the 0.2% proof stress after heating at 350 ° C. for 4 hours is 416 MPa
• heating at 350 ° C. for 4 hours The subsequent elongation value of 2.2% was indicated.
• the electrolytic copper foil according to the present application described above simultaneously has physical properties of “normal 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 with a thin electrolytic copper foil, there are few wrinkles and good handling characteristics are provided.
• Such an electrolytic copper foil has good high temperature heat resistance even when subjected to a high temperature load, and as a surface-treated copper foil subjected to various surface treatments as necessary, a printed wiring board, a lithium ion secondary battery, etc. It can be suitably used in the field.
• the manufacturing method of the electrolytic copper foil according to the present application is only to change the sulfuric acid copper electrolytic solution of the electrolytic copper foil, and the conventional electrolytic copper foil manufacturing equipment can be used as it is, so that no new capital investment is required. This is preferable.

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