JPWO2016035604A1 - Blackened surface treated copper foil and copper foil with carrier foil - Google Patents

Abstract

Provided is a blackened surface-treated copper foil having a treated surface blackened by fine roughening using copper particles. In this blackened surface-treated copper foil, the treated surface has a root mean square slope RΔq of a roughness curve measured in accordance with JIS B 0601 (2001) of 25 or less, and JIS Z 8729. (2004) and a blackened surface-treated copper foil having a lightness L * of an L * a * b * color system measured in accordance with JIS Z 8722 (2009) of 30 or less. According to the present invention, when being bonded to a resin film and processed into a stripe or mesh wiring for a touch panel, the film transparency after copper foil etching can be increased, and the stripe or mesh wiring It is possible to provide a blackened surface-treated copper foil capable of realizing a desirable black color sufficient to reduce the visibility of the surface.

Description

  The present invention relates to a blackened surface-treated copper foil and a copper foil with a carrier.

  In recent years, touch panels have been adopted for operation units of various electronic devices such as mobile phones and portable information terminals. A touch panel is an electronic component that combines an input device that detects the contact position of a fingertip or pen tip on the display surface of a display panel such as a liquid crystal display device. Convenient in that input operations can be performed. There are various types of touch panels such as a resistance film type and a capacitance type depending on the structure and detection method.

  In particular, the capacitive touch panel detects the position by detecting the change in capacitance between the fingertip and the conductive film, and takes advantage of the fact that electrostatic coupling occurs when the finger is close to the panel surface. Thus, it is possible to express and operate to display a cursor before touching. There are two types of electrostatic capacity methods: surface type and projection type. As shown in FIG. 1, the projected capacitive touch panel 10 includes two transparent electrode layers 12 and 12 ′ that are patterned in the x-axis direction and the y-axis direction, with an insulating layer 14 interposed therebetween. The touched position is detected from the change in capacitance between the electrodes, and can be detected with high accuracy at multiple points. Therefore, the touched position is employed in portable devices such as smartphones. In FIG. 1, the laminate of transparent electrode layer 12 / insulating layer 14 / transparent electrode layer 12 ′ is sandwiched between a glass substrate 16 and a protective cover 18.

  In recent years, it has been proposed to use a copper foil processed into a striped or mesh copper wiring instead of the ITO (indium tin oxide) transparent electrode that has been widely used in the past in capacitive touch panels. . Such a copper wiring has a lower resistance than the ITO transparent electrode, and therefore, a touch panel with higher sensitivity and excellent operational stability can be realized. For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-206315) discloses a touch panel sensor including striped or meshed copper wirings in each of the portions where the front surface and the back surface of the film need to be seen through. Although the copper wiring is inherently highly reflective due to the specular reflection unique to the metal, the touch panel sensor of Patent Document 1 uses an oxide film on the visible side of the copper wiring to blacken the surface, so that the copper wiring The reflection of the light is kept low, thereby suppressing the decrease in contrast when mounted as a touch panel sensor on the display. In addition, the formation of the striped or meshed copper wiring is performed by performing patterning by photolithography and etching removal of the copper foil on the laminated body in which the copper foil is bonded to the film, and then the copper wiring is visually recognized. The blackening treatment is performed using an alkaline chemical solution on the side of the surface.

  On the other hand, as a copper foil used for an electromagnetic wave shielding conductive mesh for a plasma display front panel, a copper foil subjected to blackening or browning is known. For example, Patent Document 2 (WO2007 / 007870) discloses a surface-treated copper foil having a nickel-based blackening treatment surface or a cobalt-based blackening treatment surface on the surface of an untreated copper foil. Moreover, patent document 3 (Unexamined-Japanese-Patent No. 2005-187913) has disclosed the browning surface treatment copper foil provided with the brown surface formed by the copper plating performed in multistep.

JP 2013-206315 A International Publication No. 2007/007870 JP-A-2005-187913

  By the way, if the surface-treated copper foil previously blackened or browned as disclosed in the cited document 2 or the cited document 3 can be used as a wiring material for the touch panel sensor, it is advantageous because it is not necessary to separately perform the blackening process. is there. On the other hand, since the copper wiring of stripe shape etc. like patent document 1 is formed by etching away copper foil, in order to make the image displayed on touch panels, such as a liquid crystal display device clear, copper foil It is important to ensure the transparency of a film (for example, a resin film such as a PET film) at a location where is etched. Because the transparency of the film at the location where the copper foil was etched (hereinafter referred to as the transparency of the film after etching the copper foil), the surface profile such as the surface roughness of the copper foil that existed there was a film. This is because it is inherited by the surface and is greatly influenced by the surface profile of the copper foil. In this respect, the surface-treated copper foil described in Patent Document 2 is excellent in the transparency of the film after etching the copper foil, but is not easily dissolved in copper etching solution than copper, but is nickel-based blackening treatment or cobalt-based blackening. Since the treatment is performed, line variations during etching occur, or the copper etching solution is contaminated, making it difficult to control the solution concentration. Moreover, since the surface-treated copper foil described in Patent Document 3 does not include a dissimilar metal that causes etching inhibition on the surface of the browning treatment, the line variation during etching as in the blackening treatment of Patent Literature 2 is less likely to occur. The multi-stage burn plating deteriorates the transparency of the film after etching the copper foil, so that the backlight is scattered and the image on the liquid crystal display section is difficult to see clearly.

  The inventors of the present invention have blackened the copper foil by fine roughening using copper particles, thereby reducing the unevenness of the treatment surface and the inclination thereof, thereby bonding the resin film to a stripe or mesh for a touch panel. When processed into a shaped wiring, the transparency of the film after copper foil etching can be increased, and a desirable black color sufficient to reduce the visibility of stripes or mesh-like wiring can be realized. Obtained knowledge.

  Therefore, the object of the present invention is to increase the film transparency after etching a copper foil when it is bonded to a resin film and processed into a stripe or mesh wiring for a touch panel, and the stripe or mesh An object of the present invention is to provide a blackened surface-treated copper foil suitable for use as an electrode material for a touch panel, capable of realizing a desirable black color sufficient to reduce the visibility of a wire-like wiring. Another object of the present invention is to provide a copper foil with a carrier foil provided with such a blackened surface-treated copper foil.

According to one aspect of the present invention, a blackened surface-treated copper foil having a treated surface blackened by fine roughening using copper particles,
The treated surface has a root mean square slope RΔq of a roughness curve measured in accordance with JIS B 0601 (2001) of 25 or less, and conforms to JIS Z 8729 (2004) and JIS Z 8722 (2009). Provided is a blackened surface-treated copper foil having a lightness L ^{* of} L ^* a ^* b ^* color system measured in conformity with 30 or less.

  According to another aspect of the present invention, a carrier foil, a release layer provided on the carrier foil, and the blackened surface-treated copper of the invention provided on the release layer with the treated surface outside. A copper foil with a carrier foil is provided.

It is a figure which shows the general structure of a projection type capacitive touch panel. It is a figure which shows an example of the copper wiring for touchscreens. It is a figure which shows another example of the copper wiring for touchscreens.

Blackened surface-treated copper foil The copper foil of the present invention is a blackened surface-treated copper foil. This blackened surface-treated copper foil has a treated surface that is blackened by fine roughening using copper particles. By being blackened by fine roughening using copper particles, the roughness curve of the treated surface has small irregularities, and is characterized by the small inclination of the irregularities. The treatment surface having a small inclination of the unevenness is defined by a root mean square slope RΔq of the roughness curve measured in accordance with JIS B 0601 (2001) being 25 or less. Because of the small slope of such irregularities, that is, RΔq, when the film is bonded to a resin film (for example, a PET film) and processed into a stripe or mesh wiring for a touch panel, the transparency of the film after etching the copper foil Can be significantly increased. As described above, in order to clearly display an image displayed on a touch panel such as a liquid crystal display device, it is important to ensure transparency of the film after etching the copper foil. By using this, the transparency of this film can be realized. Moreover, this blackened surface-treated copper foil can achieve a desirable black color sufficient to reduce the visibility of stripes or mesh-like wiring, and this characteristic is JIS Z 8729 (2004) and JIS Z 8722 (2009). The lightness L ^{* of the} L ^* a ^* b ^* color system measured in accordance with the above is defined as 30 or less. As described above, the copper wiring originally has a high reflectivity due to the specular reflection characteristic of metal, but by blackening the lightness L ^* as described above, the display image when mounted on a display as a touch panel sensor is clear. Can be. Thus, according to the present invention, when processed into a stripe for a touch panel or a mesh-like wiring by being bonded to a resin film, the film transparency after copper foil etching can be increased, and the stripe Alternatively, a blackened surface-treated copper foil capable of realizing a desirable black color sufficient to reduce the visibility of the mesh wiring is provided.

  Therefore, the blackened surface-treated copper foil of the present invention is preferably used as a wiring material for a touch panel sensor, and becomes a better alternative material having a lower resistance than the ITO transparent electrode that has been widely used in conventional touch panel sensors. When the blackened surface-treated copper foil of the present invention is used as a wiring material for a touch panel sensor, as shown in FIG. 2A, in the configuration in which the copper wiring 22 and the film 24 are laminated (in FIG. 2A, It is preferable to arrange the blackened treated surface 22a facing the film 24 side). Further, as shown in FIG. 2B, copper wirings 22 and 22 ′ may be laminated on both surfaces of the film 24. In this case, at least the upper copper wiring 22 ′ is the side that is visually recognized (in FIG. 2B, the film It is preferable to arrange the blackened treatment surface 22a ′ on the wiring 22 ′ side with respect to 24, and the blackened treatment surface 22a on the side where the copper wirings 22 and 22 ′ on both sides are visually recognized. 22a 'may be directed. 2A and 2B, the copper wiring may have a blackened treatment surface on the side opposite to the side to be visually recognized.

  The blackened surface-treated copper foil of the present invention has a treated surface blackened by fine roughening using copper particles. Thus, since the blackened process surface of this invention is comprised with a copper particle, it is excellent in etching property. In other words, nickel-based blackening treatment or cobalt-based blackening treatment, which is less soluble than copper with respect to the copper etching solution disclosed in Patent Document 2, causes line variations during etching or contamination of the copper etching solution. As a result, it becomes difficult to control the liquid concentration, but such drawbacks are eliminated. Therefore, it is preferable that a copper particle consists of copper and an unavoidable impurity. The particle size of the copper particles is not particularly limited. This is because the particle diameter of the copper particles is reflected in the surface property parameters such as the root mean square slope RΔq of the roughness curve, the average height Rc of the roughness curve element, the arithmetic average roughness Ra, and the like, and the evaluation is made using those parameters. This is enough. However, it can be said that the particle size of the copper particles is preferably 10 nm to 250 nm. The shape of the copper particles is not particularly limited, but is preferably substantially spherical from the viewpoint of effectively preventing powder falling off.

によって規定されるものである。このようにＲΔｑは凹凸の傾斜を平均化したパラメータであり、処理表面におけるコブの有無を明確に示唆する。すなわち、ＲΔｑが高すぎるとコブや凹凸が大きすぎることを意味し、銅箔エッチング後のフィルムの透明性が悪くなる。この点、ＲΔｑが２５以下であると処理表面におけるコブや凹凸が小さくなるため、銅箔エッチング後のフィルムの透明性が向上する。好ましいＲΔｑは３〜２５であり、さらに好ましくは３〜１０であり、特に好ましくは３〜８であり、最も好ましくは４〜７である。このような範囲であると、銅箔エッチング後のフィルムの透明性をさらに向上することができ、また、微細粗化量を減らしてコブで黒くすることもある程度可能となる。The treated surface of the blackened surface-treated copper foil of the present invention has a root mean square slope RΔq of the roughness curve of 25 or less. RΔq is the root mean square of the local slope dZ / dx at the reference length l of the roughness curve, measured according to JIS B 0601 (2001), and has the following formula:

It is prescribed by. Thus, RΔq is a parameter that averages the slope of the unevenness, and clearly indicates the presence or absence of bumps on the treated surface. That is, when RΔq is too high, it means that the bumps and irregularities are too large, and the transparency of the film after etching the copper foil is deteriorated. In this regard, when RΔq is 25 or less, bumps and irregularities on the treated surface are reduced, and thus the transparency of the film after the copper foil etching is improved. Preferred RΔq is 3 to 25, more preferably 3 to 10, particularly preferably 3 to 8, and most preferably 4 to 7. Within such a range, the transparency of the film after the copper foil etching can be further improved, and it becomes possible to some extent to reduce the amount of fine roughening and make it black with a bump.

The treated surface of the blackened surface-treated copper foil of the present invention has an L ^* a ^* b ^* color system brightness L ^* of 30 or less measured according to JIS Z 8729 (2004) and JIS Z 8722 (2009). Preferably, it is 20 or less, more preferably 15 or less, and still more preferably 13 or less. Although a lower limit is not specifically limited, For example, it is 0.5 or more. The lightness L ^* means that the lower the value, the darker the color appears, and the higher the value, the brighter the color appears. In this respect, when it is within the above range, the visibility of the stripe or mesh wiring can be more effectively reduced when it is bonded to a resin film and processed into a stripe or mesh wiring for a touch panel. . As a result, a display image when mounted on a display as a touch panel sensor can be made clear.

  The treated surface of the blackened surface-treated copper foil of the present invention preferably has a XYZ color system Y value of 10 or less measured according to JIS Z 8701 (1999) and JIS Z 8722 (2009). More preferably, it is 5 or less. The lower limit is not particularly limited, but is typically 0.5 or more. The Y value is called luminous reflectance, and is a parameter having both green and reflectance. Particularly, it is preferable that the Y value is 10 or less in that the phenomenon that the sensor of the display unit is reflected and looks whitish as a result of the low reflectance can be effectively avoided or suppressed.

The treated surface of the blackened surface-treated copper foil of the present invention has an L ^* a ^* b ^* color system a ^* value of 4 or less measured according to JIS Z 8729 (2004) and JIS Z 8722 (2009). More preferably, it is -5-3, More preferably, it is -3-2. The a ^* value in the L ^* a ^* b ^* color system means that the higher the value, the reddish color tone, but the reddish color tone tends to be noticeable to human eyes. In this regard, in the application of the wiring material for the touch panel sensor, it can be said that if the a ^* value is in the above range, redness is not emphasized and the wiring becomes more inconspicuous so that a more desirable color tone is exhibited.

  The treated surface of the blackened surface-treated copper foil of the present invention preferably has an average height Rc of a roughness curve element measured in accordance with JIS B 0601 (2001) of 0.1 to 1.0 μm. More preferably, it is 0.1-0.8 micrometer, More preferably, it is 0.1-0.5 micrometer, Most preferably, it is 0.2-0.4 micrometer. When the thickness is within the above range, circuit peeling hardly occurs and the linearity of the circuit pattern is also easily realized when bonded to a resin film and processed into a touch panel stripe or mesh wiring.

  The treated surface of the blackened surface-treated copper foil of the present invention preferably has an arithmetic average roughness Ra measured in accordance with JIS B 0601 (2001) of 0.10 to 0.35 μm, more preferably 0. .15 to 0.25 μm, more preferably 0.20 to 0.25 μm. When the thickness is within the above range, circuit peeling hardly occurs and the linearity of the circuit pattern is also easily realized when bonded to a resin film and processed into a touch panel stripe or mesh wiring.

  When the blackened surface-treated copper foil of the present invention is bonded to one side of a polyethylene terephthalate resin (PET) film having a thickness of 100 μm on the treated surface side and then removed by etching. In addition, it is preferable that the remaining polyethylene terephthalate resin film has a haze value (Haze) of 60% or less, more preferably 50% or less, still more preferably 45% or less, particularly preferably 20% or less, and most preferably. Is 10% or less. Although a lower limit is not specifically limited, For example, it is 1% or more. Since the haze value means haze, a low haze value as described above means high transparency. Therefore, when the blackened surface-treated copper foil having such a configuration is bonded to a resin film and processed into a stripe or mesh wiring for a touch panel, the transparency of the film after etching the copper foil is increased. Can do. The haze value was determined by thermo-compressing a blackened surface-treated copper foil and a PET film (thickness 100 μm) to produce a copper-clad laminate, and then removing the surface-treated copper foil by etching. Using a commercially available haze meter (for example, NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.), the haze value (Haze: unit%) of the film at 23 ° C. was measured at three locations according to JIS K 7136 (2000). The average value may be obtained.

  The thickness of the blackened surface-treated copper foil of the present invention is not particularly limited, but is preferably 0.1 to 18 μm, more preferably 0.5 to 10 μm, still more preferably 0.5 to 7 μm, and particularly preferably 0.5. -5 μm, most preferably 0.5-3 μm. In addition, the blackened surface-treated copper foil of the present invention is not limited to the surface of the normal copper foil subjected to black roughening, but is obtained by performing black roughening of the copper foil surface of the copper foil with carrier foil. May be.

Method for Producing Blackened Surface Treated Copper Foil An example of a preferred method for producing a blackened surface treated copper foil according to the present invention will be described. However, the blackened surface treated copper foil according to the present invention is not limited to the method described below, and copper particles As long as fine roughening using is performed, it may be produced by any method.

(1) Preparation of copper foil As copper foil used for manufacture of blackened surface-treated copper foil, both electrolytic copper foil and rolled copper foil can be used. Further, the copper foil may be a non-roughened copper foil or a pre-roughened copper foil. The thickness of the copper foil is not particularly limited, but is preferably 0.1 to 18 μm, more preferably 0.5 to 10 μm, still more preferably 0.5 to 7 μm, particularly preferably 0.5 to 5 μm, and most preferably 0. 0.5-3 μm. When the copper foil is prepared in the form of a copper foil with a carrier foil, the copper foil is a wet film forming method such as an electroless copper plating method and an electrolytic copper plating method, a dry film forming method such as sputtering and chemical vapor deposition, Alternatively, it may be formed by a combination thereof.

  The surface of the copper foil to be finely roughened with copper particles preferably has a maximum waviness difference (Wmax) of 2.0 μm or less, more preferably 1.2 μm or less, and still more preferably 0.8. 8 μm or less. Although a lower limit is not specifically limited, For example, it is 0.1 micrometer or more. Within the above range, when fine roughening with copper particles is performed, the slope of the irregularities defined by the root mean square slope RΔq of the roughness curve can be reduced, and the resin film (eg, PET film) can be reduced. When bonded and processed into a stripe or mesh wiring for a touch panel, the transparency of the film after etching the copper foil can be significantly increased. The “maximum undulation height difference (Wmax)” is the height difference in the waveform data extracted by filtering the waveform data relating to undulation from the information on the unevenness of the sample surface obtained using a three-dimensional surface structure analysis microscope. (The sum of the maximum peak height and the maximum valley depth of the waveform). For example, zygo New View 5032 (manufactured by Zygo) is used as a measuring instrument, and Metro Pro Ver. With 8.0.2, the low frequency filter can be measured by employing the condition of 11 μm.

(2) Black roughening At least one surface of the copper foil is blackened by fine roughening using copper particles. This black roughening is performed by electrolysis using a black roughening copper electrolytic solution. A preferable copper electrolytic solution for roughening black is an electrolytic solution having a copper concentration of 10 to 20 g / L, a free sulfuric acid concentration of 30 to 100 g / L, and a chlorine concentration of 20 to 100 ppm. Here, when the copper concentration is less than 10 g / L, the electrodeposition rate of the copper particles is slow, which is not preferable because it does not satisfy industrially required productivity. On the other hand, if the copper concentration exceeds 20 g / L, it is not preferable because it approaches smooth plating conditions and makes it difficult to roughen the black in relation to the current density described later. If the concentration of free sulfuric acid deviates from this concentration range due to the relationship with the copper concentration, the current-carrying characteristics during electrolysis change and it becomes difficult to achieve good black roughening.

  It is preferable to control the fine roughening by further adding an additive to the black roughening copper electrolytic solution. Preferable examples of such additives include a combination of polyethylene glycol and bis (3-sulfopropyl) disulfide, sodium polyacrylate, and the like. For example, polyethylene glycol and bis (3-sulfopropyl) disulfide are preferably added to the black roughening copper electrolytic solution at a concentration of 10 to 500 ppm. Sodium polyacrylate is preferably added to the black roughening copper electrolytic solution at a concentration of 10 to 1000 ppm. Thus, by adding an additive singly or in appropriate combination, acicular grain growth can be suppressed and spherical fine roughened particles can be formed.

Electrolysis using the black roughening copper electrolytic solution is performed under conditions of a current density of 30 to 100 A / dm ² and a time of ² to 10 sec in an electrolytic solution having a solution temperature of 20 to 40 ° C. Is preferred. When the solution temperature is less than 20 ° C., the shape of the coarse particles to be formed tends to vary, which is not preferable. On the other hand, if the solution temperature exceeds 40 ° C., the solution property of the black roughening copper electrolytic solution tends to change, and there is a tendency that stable fine roughening cannot be performed. Further, when the current density is less than 30 A / dm ² , it is not preferable because sufficient black roughening cannot be performed and it becomes difficult to set the lightness L ^* of the black roughened surface to 30 or less. On the other hand, when the current density exceeds 100 A / dm ² , the precipitation rate of fine copper particles becomes excessive, and the shape of the formed copper particles does not become a good spherical body, which is not preferable.

(3) Rust prevention treatment If desired, the copper foil after the roughening of black may be subjected to a rust prevention treatment. The rust prevention treatment preferably includes a plating treatment using zinc. The plating treatment using zinc may be either a zinc plating treatment or a zinc alloy plating treatment, and the zinc alloy plating treatment is particularly preferably a zinc-nickel alloy treatment. The zinc-nickel alloy treatment may be a plating treatment containing at least Ni and Zn, and may further contain other elements such as Sn, Cr, and Co. The Ni / Zn adhesion ratio in the zinc-nickel alloy plating is preferably 1.2 to 10, more preferably 2 to 7, still more preferably 2.7 to 4, in terms of mass ratio. The rust prevention treatment preferably further includes a chromate treatment, and this chromate treatment is more preferably performed on the surface of the plating containing zinc after the plating treatment using zinc. By carrying out like this, rust prevention property can further be improved. A particularly preferable antirust treatment is a combination of a zinc-nickel alloy plating treatment and a subsequent chromate treatment.

(4) Silane coupling agent treatment If desired, the copper foil may be treated with a silane coupling agent to form a silane coupling agent layer. Thereby, moisture resistance, chemical resistance, adhesiveness with an adhesive agent, etc. can be improved. The silane coupling agent layer can be formed by appropriately diluting and applying a silane coupling agent and drying. Examples of silane coupling agents include epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane, or γ-aminopropyltriethoxysilane, N-β (amino Amino functions such as ethyl) γ-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane Silane coupling agent, or mercapto functional silane coupling agent such as γ-mercaptopropyltrimethoxysilane, or olefin functional silane coupling agent such as vinyltrimethoxysilane, vinylphenyltrimethoxysilane, or γ-methacryloxypropyl Trimetoki Acrylic-functional silane coupling agent such as a silane, or imidazole functional silane coupling agent such as imidazole silane, or triazine functional silane coupling agents such as triazine silane.

Copper foil with carrier foil The blackened surface-treated copper foil of the present invention can be provided in the form of a copper foil with carrier foil. In particular, in order to make a display image when mounted on a display as a touch panel sensor clear, when a narrower circuit pattern width or a copper wiring height is 5 μm or less, a thin copper foil is used. From the viewpoint of improving handling properties, it is preferable to use a copper foil with a carrier. In this case, the copper foil with a carrier foil is a carrier foil, a release layer provided on the carrier foil, and the blackened surface-treated copper of the present invention provided on the release layer with the blackened treatment surface outside. It is provided with foil. However, the copper foil with carrier foil can employ a known layer configuration except that the blackened surface-treated copper foil of the present invention is used.

  The carrier foil is a foil for supporting the blackened surface-treated copper foil and improving its handleability. Examples of the carrier foil include an aluminum foil, a copper foil, a resin film whose surface is metal-coated, and the like, and preferably a copper foil. The copper foil may be a rolled copper foil or an electrolytic copper foil. The thickness of the carrier foil is typically 200 μm or less, preferably 18 μm to 200 μm.

  The release layer is a layer having a function of weakening the peeling strength of the carrier foil, ensuring the stability of the strength, and further suppressing interdiffusion that may occur between the carrier foil and the copper foil during press molding at a high temperature. It is. The release layer is generally formed on one side of the carrier foil, but may be formed on both sides. The release layer may be either an organic release layer or an inorganic release layer. Examples of organic components used in the organic release layer include nitrogen-containing organic compounds, sulfur-containing organic compounds, carboxylic acids and the like. Examples of nitrogen-containing organic compounds include triazole compounds, imidazole compounds, and the like. Among these, triazole compounds are preferred in terms of easy release stability. Examples of triazole compounds include 1,2,3-benzotriazole, carboxybenzotriazole, N ′, N′-bis (benzotriazolylmethyl) urea, 1H-1,2,4-triazole and 3-amino- 1H-1,2,4-triazole and the like can be mentioned. Examples of the sulfur-containing organic compound include mercaptobenzothiazole, thiocyanuric acid, 2-benzimidazolethiol and the like. Examples of the carboxylic acid include monocarboxylic acid and dicarboxylic acid. On the other hand, examples of inorganic components used in the inorganic release layer include Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, and a chromate-treated film. The release layer may be formed by bringing a release layer component-containing solution into contact with at least one surface of the carrier foil and fixing the release layer component to the surface of the carrier foil. The contact of the carrier foil with the release layer component-containing solution may be performed by immersion in the release layer component-containing solution, spraying of the release layer component-containing solution, flowing down of the release layer component-containing solution, or the like. The release layer component may be fixed to the surface of the carrier foil by drying the release layer component-containing solution, electrodeposition of the release layer component in the release layer component-containing solution, or the like. The thickness of the release layer is typically 1 nm to 1 μm, preferably 5 nm to 500 nm.

  As the blackened surface-treated copper foil, the above-described blackened surface-treated copper foil of the present invention is used. The blackened surface-treated copper foil of the present invention has been subjected to fine roughening (blackening) using copper particles, but as a procedure, first, a copper layer is formed on the surface of the release layer as a copper foil, Thereafter, at least fine roughening (blackening) may be performed. The details of the fine roughening (blackening) are as described above. In addition, it is preferable that copper foil is comprised with the form of an ultra-thin copper foil in order to utilize the advantage as copper foil with a carrier. A preferable thickness of the ultrathin copper foil is 0.1 μm to 7 μm, more preferably 0.5 μm to 5 μm, and still more preferably 0.5 μm to 3 μm.

  Another functional layer may be provided between the release layer and the copper foil. An example of such another functional layer is an auxiliary metal layer. The auxiliary metal layer is preferably made of nickel and / or cobalt. The thickness of the auxiliary metal layer is preferably 0.001 to 3 μm.

  The present invention is more specifically described by the following examples.

Example 1 : Blackened surface-treated copper foil Production and evaluation of a blackened surface-treated copper foil were performed as follows.

(1) Preparation of electrolytic copper foil An acidic copper sulfate solution having the following composition was used as the copper electrolyte, a titanium rotating electrode having a surface roughness Ra of 0.20 μm was used for the cathode, and DSA ( Using a dimensionally stable anode), electrolysis was performed at a solution temperature of 45 ° C. and a current density of 55 A / dm ² to obtain an electrolytic copper foil having a thickness of 12 μm. The maximum height difference (Wmax) of the waviness of the deposited surface of this electrolytic copper foil was 0.8 μm, and the maximum height difference (Wmax) of the waviness of the electrode surface was 1.5 μm.
<Composition of sulfuric acid copper sulfate solution>
-Copper concentration: 80 g / L
-Free sulfuric acid concentration: 140 g / L
-Bis (3-sulfopropyl) disulfide concentration: 30 mg / L
-Diallyldimethylammonium chloride polymer concentration: 50 mg / L
-Chlorine concentration: 40 mg / L

<Maximum wave height difference (Wmax)>
Zygo New View 5032 (manufactured by Zygo) was used as a measuring instrument, and Metro Pro Ver. The maximum height difference (Wmax) of the waviness was measured by using the condition of 11 μm for the low frequency filter using 8.0.2. At this time, the surface to be measured of the surface-treated copper foil is fixed in close contact with the sample stage, and 6 fields of 108 μm × 144 μm are selected and measured within the 1 cm square range of the sample piece, and 6 measurements are made. The average value of the maximum height difference (Wmax) of the swell obtained from the points was adopted as a representative value.

(2) Black roughening Among the electrode surface and precipitation surface provided in the above-mentioned electrolytic copper foil, a black roughening copper electrolytic solution having the following composition is used for the precipitation surface side, the solution temperature is 30 ° C., and the current is Blackening was performed by electrolysis under conditions of a density of 50 A / dm ² and a time of 4 seconds.
<Composition of copper electrolytic solution for black roughening>
-Copper concentration: 13 g / L
-Free sulfuric acid concentration: 70 g / L
-Chlorine concentration: 35 mg / L
-Polyethylene glycol concentration: 100ppm
-Bis (3-sulfopropyl) disulfide concentration: 100 ppm

(3) Rust prevention treatment Rust prevention treatment consisting of inorganic rust prevention treatment and chromate treatment was performed on both surfaces of the electrolytic copper foil after blackening. First, as an inorganic rust prevention treatment, using a pyrophosphate bath, potassium pyrophosphate concentration 80 g / L, zinc concentration 0.2 g / L, nickel concentration 2 g / L, liquid temperature 40 ° C., current density 0.5 A / dm ² Zinc-nickel alloy rust prevention treatment was performed. Next, as a chromate treatment, a chromate layer was further formed on the zinc-nickel alloy rust prevention treatment. This chromate treatment was performed at a chromic acid concentration of 1 g / L, pH 11, a solution temperature of 25 ° C., and a current density of 1 A / dm ² .

(4) Silane coupling agent treatment The copper foil subjected to the above rust prevention treatment is washed with water, and then immediately treated with a silane coupling agent to adsorb the silane coupling agent on the rust prevention treatment layer on the black roughened surface. It was. In this silane coupling agent treatment, pure water is used as a solvent, a solution having a 3-aminopropyltrimethoxysilane concentration of 3 g / L is used, and this solution is sprayed onto the black roughened surface by showering to perform an adsorption treatment. went. After adsorption of the silane coupling agent, water was finally evaporated by an electric heater to obtain a blackened surface-treated copper foil having a thickness of 12 μm.

(5) Evaluation About the obtained blackening surface-treated copper foil, various characteristics were evaluated as follows.

<Surface property parameters (RΔq, Rc and Ra)>
Using a laser microscope (OLS4100, manufactured by Olympus) as an optical measuring device, surface property parameters RΔq, Rc, and Ra of the surface-treated copper foil were measured in accordance with JIS B 0601 (2001). In this measurement, the evaluation length was 642 μm, and the measurement was performed in the width direction of the copper foil. Here, the width direction of the copper foil corresponds to the width direction (TD direction) of the rotating cathode during the production of the electrolytic copper foil.

<Lightness L ^* , chromaticity a ^* and Y value>
Using a spectral colorimeter (Nippon Denshoku Industries Co., Ltd., SE6000), the lightness L ^* and chromaticity a ^* are based on JIS Z 8729 (2004) and JIS Z 8722 (2009), and the Y value is JIS Z. It was measured according to 8701 (1999) and JIS Z 8722 (2009).

<Haze value>
A surface-treated copper foil and a PET film (thickness 100 μm) were thermocompression bonded to produce a copper-clad laminate. Thereafter, the surface-treated copper foil was removed by etching, and the remaining PET film was filmed at 23 ° C. according to JIS K 7136 (2000) using a haze meter (NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.). The haze value (Haze: unit%) was measured at three locations, and the average value was obtained.

Example 2
A blackened surface-treated copper foil was prepared and evaluated in the same manner as in Example 1 except that the blackening was performed on the electrode surface side of the electrolytic copper foil.

Example 3
Preparation and evaluation of the copper foil with carrier foil provided with the blackened surface-treated copper foil were performed as follows.

(1) Preparation of carrier foil An acidic copper sulfate solution having the following composition is used as the copper electrolyte, a titanium rotating electrode having a surface roughness Ra of 0.20 μm is used as the cathode, and a DSA (dimension) is used as the anode. Using a stable anode), electrolysis was performed at a solution temperature of 45 ° C. and a current density of 55 A / dm ² to obtain an electrolytic copper foil having a thickness of 12 μm as a carrier foil.
<Composition of sulfuric acid copper sulfate solution>
-Copper concentration: 80 g / L
-Free sulfuric acid concentration: 140 g / L
-Bis (3-sulfopropyl) disulfide concentration: 30 mg / L
-Diallyldimethylammonium chloride polymer concentration: 50 mg / L
-Chlorine concentration: 40 mg / L

(2) Formation of organic release layer The electrode surface side of the pickled copper foil for carrier was placed in a CBTA aqueous solution containing 1000 ppm by weight of CBTA (carboxybenzotriazole), 150 g / l of sulfuric acid and 10 g / l of copper at a liquid temperature of 30. The CBTA component was adsorbed on the electrode surface of the carrier foil by dipping for 30 seconds at 0 ° C. Thus, a CBTA layer was formed as an organic release layer on the glossy surface of the carrier copper foil.

(3) Auxiliary metal layer formation The carrier copper foil on which the organic release layer was formed was immersed in a solution containing 20 g / l nickel and 300 g / l potassium pyrophosphate prepared using nickel sulfate, and the liquid temperature was 45. Nickel having a deposition amount corresponding to a thickness of 0.002 μm was deposited on the organic release layer under the conditions of ° C., pH 3, and current density 5 A / dm ² . Thus, a nickel layer was formed as an auxiliary metal layer on the organic release layer.

(4) Ultra-thin copper foil formation The carrier copper foil on which the auxiliary metal layer is formed is immersed in an acidic copper sulfate solution and electrolyzed for 60 seconds under a smooth plating condition with a current density of 8 A / dm ² to obtain a thickness of 3 μm. The ultrathin copper foil was formed on the auxiliary metal layer. The maximum height difference (Wmax) of the waviness of the deposited surface of this ultrathin copper foil was 1.1 μm.

(5) Black roughening For the precipitation surface of the ultrathin copper foil, a black roughening copper electrolytic solution having the composition shown below was used, and the solution temperature was 30 ° C., the current density was 50 A / dm ² , and the time was 4 sec. Electrolysis was performed under conditions to perform black roughening.
<Composition of copper electrolytic solution for black roughening>
-Copper concentration: 13 g / L
-Free sulfuric acid concentration: 70 g / L
-Chlorine concentration: 35 mg / L
-Sodium polyacrylate concentration: 400ppm

(6) Rust prevention treatment Rust prevention treatment consisting of inorganic rust prevention treatment and chromate treatment was performed on both surfaces of the ultrathin copper foil with carrier foil after black roughening. First, as an inorganic rust prevention treatment, using a pyrophosphate bath, potassium pyrophosphate concentration 80 g / L, zinc concentration 0.2 g / L, nickel concentration 2 g / L, liquid temperature 40 ° C., current density 0.5 A / dm ² Zinc-nickel alloy rust prevention treatment was performed. Next, as a chromate treatment, a chromate layer was further formed on the zinc-nickel alloy rust prevention treatment. This chromate treatment was performed at a chromic acid concentration of 1 g / L, pH 11, a solution temperature of 25 ° C., and a current density of 1 A / dm ² .

(7) Silane coupling agent treatment The copper foil that has been subjected to the above rust prevention treatment is washed with water and then immediately treated with a silane coupling agent to adsorb the silane coupling agent on the rust prevention treatment layer on the black roughened surface. It was. In this silane coupling agent treatment, pure water is used as a solvent, a solution having a 3-aminopropyltrimethoxysilane concentration of 3 g / L is used, and this solution is sprayed onto the black roughened surface by showering to perform an adsorption treatment. went. After the adsorption of the silane coupling agent, moisture was finally diffused by an electric heater to obtain a copper foil with a carrier foil, which was provided with a blackened surface-treated ultrathin copper foil having a thickness of 3 μm.

(8) Evaluation About the copper foil with a carrier foil provided with the obtained blackened surface-treated copper foil, various characteristics were evaluated in the same manner as in Example 1.

Example 4 (Comparison)
A browned surface-treated copper foil was prepared and evaluated in the same manner as in Example 1 except that the browning treatment described below was performed on the electrode surface side of the electrolytic copper foil instead of the black roughening.

<Browning treatment>
First, an electrolytic copper foil that was not roughened (prepared in Example 1 (1)) was immersed in a dilute sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. for 30 seconds to clean the surface. Made. The electrolytic copper foil thus cleaned was subjected to the browning treatment by performing the following steps (a) to (e) in this order.

(A) Basic plating treatment step A basic plating treatment for browning the surface of the copper foil was performed on the electrode surface side of the electrolytic copper foil using a copper sulfate-based plating solution under burn plating conditions. This basic plating treatment is performed by electrolysis under a burn plating condition of a current density (Ia) of 10 A / dm ² using a copper sulfate solution having a copper concentration of 18 g / l, a free sulfuric acid concentration of 100 g / l, and a liquid temperature of 25 ° C. It was. As a result, the burn plating performed in this basic plating process only formed nuclei for forming a certain degree of irregularities on the copper foil surface, and the electrodeposition amount was 300 mg / m ² in terms of converted thickness.

(B) Additional plating treatment process The surface of the copper foil thus subjected to the basic plating treatment was subjected to a single plating treatment using a copper sulfate-based plating solution under burn plating conditions. The additional plating treatment at this time was performed using a copper sulfate solution having the same concentration and temperature as in the step (a). At this time, the current density (Ib) employed when burning plating is 1.5 A / dm ^{2 which} is 15% of Ia, and the current concentration on the nucleus formed on the surface of the copper foil in step (a) To prevent unnecessary abnormal precipitation. The electrodeposition amount in this additional plating step was an electrodeposition amount of 50 mg / m ² as a converted thickness.

(C) Cover plating treatment step The copper foil surface thus subjected to burnt plating was subjected to a cover plating treatment under a smooth plating condition using a copper plating solution. This coating plating was performed by electrolysis under a smooth plating condition with a current density of 15 A / dm ² using a copper sulfate solution having a copper concentration of 65 g / l, a free sulfuric acid concentration of 150 g / l, and a liquid temperature of 45 ° C. In this way, the surface roughened in steps (a) and (b) was smoothed. The converted thickness of the smooth plating at this time was 4 g / m ² .

(D) Finish plating process The surface subjected to the smooth plating process is subjected to a finish plating process for finishing the copper foil surface brown by using the copper plating solution under the condition of burnt plating. Was formed. The formation of this ultrafine copper grain was achieved by adding 9-phenylacridine, copper concentration of 13 g / l, free sulfuric acid 50 g / l, 9-phenylacridine 150 mg / l, chlorine concentration 28 ppm, liquid temperature 35 ° C. Was performed under electrolysis conditions with a current density of 24 A / dm ² . The electrodeposition amount in the finish plating process was 300 mg / m ² as the converted thickness.

(E) Washing and drying process The copper foil thus finish-plated is sufficiently washed by showering pure water, and stays in a drying furnace at an atmospheric temperature of 150 ° C. for 4 seconds by an electric heater. To obtain a surface-treated copper foil having a browned surface. The washing with water was not limited to this step, and was appropriately performed so as not to bring the solution of the previous step into the subsequent step between the aforementioned steps.

Example 5 (Comparison)
A surface-treated copper foil was prepared and evaluated in the same manner as in Example 2 except that black roughening was not performed.

Results The evaluation results obtained in Examples 1 to 5 were as shown in Table 1.

From the results shown in Table 1, in Examples 1 to 3 in which blackened surface-treated copper foils having RΔq of 25 or less and L ^* a ^* b ^* color system brightness L ^* of 30 or less were prepared. It can be seen that a low haze value is realized, and therefore the film transparency after etching the copper foil is high. Also, a desirable black color sufficient to reduce the visibility of the stripe or mesh wiring is realized. Furthermore, in Examples 1 to 3, all the a ^* values of the L ^* a ^* b ^* color system were low, and a desirable color tone was exhibited in which redness was not emphasized (that is, the wiring became less noticeable). Therefore, the blackened surface-treated copper foil of the present invention is extremely suitable for use as a wiring material for a touch panel sensor.

Claims (11)

A blackened surface-treated copper foil having a treated surface blackened by fine roughening using copper particles,
The treated surface has a root mean square slope RΔq of a roughness curve measured in accordance with JIS B 0601 (2001) of 25 or less, and conforms to JIS Z 8729 (2004) and JIS Z 8722 (2009). A blackened surface-treated copper foil having a L ^* a ^* b ^* color system brightness L ^* of 30 or less as measured in accordance with the standard.   2. The blackened surface-treated copper foil according to claim 1, wherein the treated surface has a Y value of an XYZ color system measured in accordance with JIS Z 8701 (1999) and JIS Z 8722 (2009) of 10 or less. .   The blackened surface-treated copper foil according to claim 1 or 2, wherein the RΔq is 3 to 10. The treated surface has an L ^* a ^* b ^* color system a ^* value of 4 or less as measured in accordance with JIS Z 8729 (2004) and JIS Z 8722 (2009). The blackening surface-treated copper foil as described in any one of Claims.   The said process surface is as described in any one of Claims 1-4 whose average height Rc of the roughness curve element measured based on JISB0601 (2001) is 0.1-1.0 micrometer. Blackened surface-treated copper foil.   The blackened surface according to any one of claims 1 to 5, wherein the treated surface has an arithmetic average roughness Ra of 0.10 to 0.35 µm measured according to JIS B 0601 (2001). Treated copper foil.   The blackening surface-treated copper foil as described in any one of Claims 1-6 in which the said copper particle consists of copper and an unavoidable impurity.   When the blackened surface-treated copper foil is bonded to one side of a polyethylene terephthalate resin film having a thickness of 100 μm on the treated surface side, the remaining polyethylene terephthalate resin film is 60% when the copper foil is removed by etching. The blackening surface-treated copper foil as described in any one of Claims 1-7 which has the following haze values.   The blackening surface-treated copper foil as described in any one of Claims 1-8 which has a thickness of 0.1-18 micrometers.   The blackening surface-treated copper foil as described in any one of Claims 1-9 used for the wiring material for touchscreen sensors. The blackened surface-treated copper foil according to any one of claims 1 to 10, provided with a carrier foil, a release layer provided on the carrier foil, and the treated surface on the release layer. A copper foil with a carrier foil.

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