Copper foil complex and preparation method thereof, copper foil as well as preparation method and application of copper foil

Abstract

The invention relates to the technical field of metal foil preparation, in particular to a copper foil complex and a preparation method thereof, copper foil and a preparation method and application of the copper foil. The copper foil composite comprises a copper foil layer and a composite support body, the composite support body comprises a support layer and a viscosity-reducing adhesive layer, and the viscosity-reducing adhesive layer is located between the support layer and the copper foil layer; the supporting layer comprises an insulating material layer and / or a metal material layer. According to the copper foil complex, the reject ratio of torn edges of the copper foil can be reduced, and the risk of fracture of the copper foil is reduced; the production efficiency is high and the width is large; and the ultra-thin copper foil without glue and supporting layer residues on the surface can be obtained in the later stage.

Description

Technical Field

[0001] This invention relates to the field of metal foil preparation technology, and more specifically, to a copper foil composite and its preparation method, copper foil and its preparation method, and its applications. Background Technology

[0002] When copper foil is used in back-end products such as IC substrates, lithium-ion batteries, and high-frequency and high-speed transmission of 5G signals, it is essential to ensure that the required copper foil is ultra-thin and low-profile copper foil (thickness ≤ 1.5μm). Low profile (surface roughness) of copper foil is a key performance indicator that can ensure stable signal transmission. Otherwise, it will lead to problems such as large delay and low efficiency in high-frequency signal transmission.

[0003] Electrolytic copper foil is produced by electrolyzing a copper sulfate solution in an electrolytic cell. The solution is used as the anode, and a cathode roller, with its bottom immersed in the copper sulfate electrolyte and rotating at a constant speed, serves as the cathode. Copper from the solution deposits onto the surface of the cathode roller to form copper foil. After the copper foil rotates out of the liquid, it is continuously peeled off from the cathode roller, washed, dried, and wound to produce the original foil. Currently, in the preparation of ultra-thin electrolytic copper foil, especially for foils less than 6 μm thick, the tensile strength and elongation of the copper foil decrease significantly for every 1 μm reduction in thickness. It is extremely prone to breakage during peeling and difficult to rewind after peeling. Due to its inherent characteristics, it is easily damaged during transportation, causing significant inconvenience for subsequent applications.

[0004] This problem also exists when using ultrathin copper foil as a printed circuit board. The method used is to support the ultrathin copper foil on a metal carrier layer. Using copper foil (thickness ≥18μm) as the carrier layer for ultrathin copper foil (thickness ≤12μm) is too cumbersome because the copper foil layer undercoating uses a copper pyrophosphate bath, followed by thick plating with a copper sulfate system. Furthermore, the residue from the release agent used also affects the recycling of the carrier copper foil.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] One object of the present invention is to provide a copper foil composite that can reduce the risk of breakage during copper foil production, and the anti-adhesion adhesive layer facilitates the separation of the copper foil layer from the support layer in the later stage, and leaves no glue or support layer residue on the surface of the copper foil layer.

[0007] Another objective of this invention is to provide a simple and easy method for preparing copper foil composites.

[0008] Another objective of this invention is to provide a method for preparing copper foil that is highly efficient, reduces the defect rate of copper foil tearing, lowers the risk of copper foil breakage, and leaves no glue or support layer residue on the copper foil surface, making it more suitable for use in the preparation of printed circuit boards.

[0009] Another object of the present invention is to provide a copper foil.

[0010] Another object of the present invention is to provide a printed circuit board.

[0011] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0012] A copper foil composite includes a copper foil layer and a composite support; the composite support includes a support layer and an anti-adhesion layer, the anti-adhesion layer being located between the support layer and the copper foil layer; the support layer includes an insulating material layer and / or a metal material layer.

[0013] In one embodiment, the copper foil composite has a tensile strength of 150–1500 MPa, a peel strength of 3–8 N / cm, a surface gloss of 20–200, and a surface roughness Ra value of 0.1–0.8 μm.

[0014] In one embodiment, the insulating material layer is made of at least one of PI, modified PET, PFA, and PDMS.

[0015] In one embodiment, the metal material layer is made of at least one of copper, titanium, aluminum, stainless steel, and tin.

[0016] In one embodiment, the thickness of the support layer is 5 to 50 μm.

[0017] In one embodiment, the anti-tack layer includes a UV anti-tack layer or a heat-resistant anti-tack layer.

[0018] In one embodiment, the thickness of the anti-adhesive layer is 3–25 μm.

[0019] In one embodiment, after the copper foil composite undergoes a de-adhesion treatment, the copper foil peel strength is 0.04 N / cm to 0.1 N / cm, and the de-adhesion treatment includes at least one of UV irradiation and heat treatment.

[0020] In one embodiment, the UV-resistant adhesive layer comprises a main resin, a UV-active substance, a curing agent, and a photoinitiator; the mass ratio of the main resin, the UV-active substance, the curing agent, and the photoinitiator is (88-93):(1-8):(0.5-5):(1-3).

[0021] In one embodiment, the main resin in the UV adhesive layer is selected from at least one of methyl acrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, and decyl methacrylate.

[0022] In one embodiment, the UV-active material in the UV-reducing adhesive layer is selected from at least one of vinyl aromatic polyurethane acrylate oligomers, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, neopentyl terephthalate triacrylate, and polydipentaerythritol hexaacrylate.

[0023] In one embodiment, the curing agent in the UV-resistant adhesive layer is selected from at least one of polyisocyanate compounds, epoxy compounds, aziridine compounds, and metal chelate compounds.

[0024] In one embodiment, the photoinitiator in the UV-resistant adhesive layer is selected from at least one of benzoin compounds, acetophenone compounds, thioxanone compounds, peroxide compounds, and acylphosphine oxide compounds.

[0025] In one embodiment, the heat-resistant adhesive layer comprises a hard monomer, a soft monomer, a functional monomer, an initiator, a curing agent, and foamed microspheres; the mass ratio of the hard monomer, soft monomer, functional monomer, initiator, curing agent, and foamed microspheres is (3-5):(20-35):(2-8):(0.1-1):(0.2-2):(1-5).

[0026] In one embodiment, the hard monomer in the heat-resistant adhesive layer is selected from at least one of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and ethylene acrylate.

[0027] In one embodiment, the soft monomer in the heat-resistant adhesive layer is selected from at least one of isooctyl acrylate, ethyl acrylate, and butyl acrylate.

[0028] In one embodiment, the functional monomer in the heat-resistant adhesive layer is selected from at least one of acrylic acid, methacrylic acid, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, acrylamide, and hydroxyacrylamide.

[0029] In one embodiment, the initiator in the heat-resistant adhesive layer is selected from benzoyl peroxide and / or azobisisobutyronitrile.

[0030] In one embodiment, the curing agent in the heat-resistant adhesive layer is selected from at least one of toluene diisocyanate, hexamethylene diisocyanate, and m-phenylenediamine epoxy resin.

[0031] The method for preparing the copper foil composite as described above includes the following steps:

[0032] A copper layer is prepared on the surface of the cathode roller by electroplating;

[0033] A composite support is hot-pressed with the copper layer to peel the copper layer off the cathode roller. After anti-oxidation treatment, a copper foil composite is obtained.

[0034] In one embodiment, the electroplating is performed using an electroplating solution comprising copper salts, conductive agents, accelerators, brighteners, leveling agents, and inhibitors.

[0035] In one embodiment, the reaction temperature of the electroplating solution is 45–60°C, and the flow rate of the electroplating solution is 35–70 m³ / h. 3 / h; the current density of the electroplating is 25-40 A / dm. 2 .

[0036] In one embodiment, the surface roughness Ra of the cathode roller is 0.1 to 0.4 μm.

[0037] In one embodiment, the electroplating solution contains copper ions at a concentration of 70–120 g / L, a conductive agent at a concentration of 85–150 g / L, an accelerator at a concentration of 10–80 ppm / L, a brightener at a concentration of 2–15 mL / L, a leveling agent at a concentration of 5–30 mL / L, and an inhibitor at a concentration of 5–30 mL / L.

[0038] In one embodiment, the copper salt includes at least one of copper sulfate, copper nitrate, and copper chloride.

[0039] In one embodiment, the conductive agent includes at least one of sulfuric acid, nitric acid, hydrochloric acid, and acetic acid.

[0040] In one embodiment, the accelerator comprises sodium polydithiopropanesulfonate.

[0041] In one embodiment, the brightener includes at least one of thiourea and sodium 3-mercapto-1-propanesulfonate.

[0042] In one embodiment, the leveling agent comprises at least one selected from polyacrylamide, Janus Green, hydroxyethyl cellulose (HEC), sodium 3-mercapto-1-propanesulfonate, and sodium polydithiodipropanesulfonate.

[0043] In one embodiment, the inhibitor comprises at least one of polyethylene glycol, sodium N-(3-sulfopropyl)-saccharin, and hydroxyethyl cellulose.

[0044] In one embodiment, the temperature of the hot-pressing composite is 100-120°C, and the pressure of the hot-pressing composite is 4-6 kg.

[0045] A method for preparing copper foil includes the following steps:

[0046] The adhesive layer in the copper foil composite is subjected to an adhesive-reducing treatment to separate the copper foil layer from the support layer, thereby obtaining copper foil; the copper foil composite is the copper foil composite obtained by the above method.

[0047] In one embodiment, the anti-tack treatment includes: irradiating the UV anti-tack adhesive layer with ultraviolet light, or heating the heat-resistant anti-tack adhesive layer.

[0048] In one embodiment, the heating temperature for the viscosity reduction treatment is 180–195°C, and the holding time is 10–18 seconds.

[0049] In one embodiment, the ultraviolet irradiation conditions for the viscosity reduction treatment are: a viscosity reduction wavelength of 390–400 nm and an irradiation intensity of 1450–1550 mJ / cm. 2 .

[0050] In one embodiment, the copper foil composite and the insulating layer are hot-pressed, and then the de-adhesion treatment and peeling are performed to obtain a copper foil laminate.

[0051] A copper foil is prepared by the method described above; the copper foil has a thickness of 0.8–2 μm, a tensile strength of 100–500 MPa, a surface gloss of 20–200, and a surface roughness Ra value of 0.1–0.8 μm.

[0052] A printed circuit board, comprising copper foil prepared by the aforementioned method.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] (1) The copper foil composite of the present invention uses a support layer as a carrier, which can improve the tensile strength of the film roll itself. The non-metallic support layer makes winding and transportation easier, and the winding radius can be increased several times, reducing the possibility of breakage during copper foil production. The anti-adhesion adhesive layer helps to separate the copper foil layer from the support layer in the later stage, and makes the surface of the copper foil layer free of glue and support layer residue.

[0055] (2) The preparation method of the copper foil composite of the present invention is simple and easy to implement.

[0056] (3) The copper foil preparation method of the present invention can reduce the defect rate of copper foil tearing, thereby reducing the risk of copper foil breakage; the surface of the ultra-thin copper foil is free of glue and support layer residue, making it more suitable for use in the preparation of printed circuit boards; it has high production efficiency and large width; the support layer surface has less glue and ultra-thin metal layer residue, making it more conducive to recycling.

[0057] (4) The copper foil obtained by the method of the present invention has excellent mechanical properties. Attached Figure Description

[0058] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of the structure of the copper foil composite of the present invention.

[0060] Figure label:

[0061] 1-Support layer, 2-Anti-adhesive layer, 3-Copper foil layer. Detailed Implementation

[0062] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0063] According to one aspect of the present invention, the present invention relates to a copper foil composite comprising a copper foil layer and a composite support; the composite support comprises a support layer and an anti-adhesion layer, the anti-adhesion layer being located between the support layer and the copper foil layer; the support layer comprises an insulating material layer and / or a metallic material layer.

[0064] The copper foil composite of the present invention uses a support layer as a carrier, which can improve the tensile strength of the film roll itself. The use of a non-metallic support layer makes winding and transportation easier, and the winding radius can be increased several times, reducing the possibility of breakage during copper foil production. It has high production efficiency and large width. The anti-adhesion adhesive layer helps to separate the copper foil layer from the support layer in the later stage, and makes the surface of the copper foil layer free of glue and support layer residue.

[0065] In one embodiment, the composite support layer is prepared by applying a non-adhesive adhesive to the surface of the selected support layer by means of coating; the coating method can be at least one of roller coating, gravure coating and slot coating.

[0066] In one embodiment, the copper foil composite has a tensile strength of 150–1500 MPa, a peel strength of 3–8 N / cm, a surface gloss of 20–200, and a surface roughness Ra value of 0.1–0.8 μm.

[0067] In one embodiment, the insulating material layer is made of at least one of PI (polyimide), modified PET (polyethylene terephthalate), PFA (a copolymer of perfluoropropyl perfluorovinyl ether and polytetrafluoroethylene), and PDMS. PDMS film is a type of polymer film prepared from polydimethylsiloxane.

[0068] In one embodiment, the metal material layer is made of at least one of copper, titanium, aluminum, stainless steel, and tin.

[0069] In one embodiment, the thickness of the support layer is 5 to 50 μm, such as 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.

[0070] In one embodiment, the anti-adhesive layer includes a UV anti-adhesive layer or a heat-resistant anti-adhesive layer. In one embodiment, the thickness of the anti-adhesive layer is 3–25 μm. This includes, but is not limited to, 3 μm, 5 μm, 6 μm, 8 μm, 10 μm, 12 μm, 15 μm, 20 μm, 22 μm, and 25 μm.

[0071] In one embodiment, after the copper foil composite undergoes a de-adhesion treatment, the copper foil peel strength is 0.04 N / cm to 0.1 N / cm, and the de-adhesion treatment includes at least one of UV irradiation and heat treatment.

[0072] In one embodiment, the UV-resistant adhesive layer comprises a main resin, a UV-active substance, a curing agent, and a photoinitiator; the mass ratio of the main resin, the UV-active substance, the curing agent, and the photoinitiator is (88-93):(1-8):(0.5-5):(1-3).

[0073] In one embodiment, the main resin in the UV-resistant adhesive layer is selected from at least one of methyl acrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, and decyl methacrylate. In another embodiment, the main resin of the present invention is one or more of the above-mentioned resins, such as a combination of methyl acrylate, ethyl methacrylate, and propyl methacrylate, or a combination of n-butyl methacrylate and isobutyl methacrylate.

[0074] In one embodiment, the UV-active material in the UV-reducing adhesive layer is selected from at least one of vinyl aromatic polyurethane acrylate oligomers, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, neopentyl terephthalate triacrylate, and polydipentaerythritol hexaacrylate. In another embodiment, the UV-active material of the present invention is any one or a combination of at least two of the above-mentioned UV-active materials, such as a combination of trimethylolpropane triacrylate and tetramethylolmethane tetraacrylate.

[0075] In one embodiment, the curing agent in the UV-resistant adhesive layer is selected from at least one of polyisocyanate compounds, epoxy compounds, aziridine compounds, and metal chelate compounds. In another embodiment, the curing agent is any one or at least two of the above, such as a combination of epoxy compounds and aziridine compounds, or a combination of aziridine compounds and metal chelate compounds.

[0076] In one embodiment, the photoinitiator in the UV-resistant adhesive layer is selected from at least one of benzoin compounds, acetophenone compounds, thioxanthone compounds, peroxide compounds, and acylphosphine oxide compounds. In another embodiment, the photoinitiator is any one or at least two of the above, such as a combination of acetophenone and thioxanthone compounds, or a combination of peroxide and acylphosphine oxide compounds. In one embodiment, the photoinitiator is 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0077] In one embodiment, the UV-resistant adhesive is applied to the surface of the insulating layer by coating, and the drying temperature during coating is 70–90°C. In another embodiment, the preparation method of the UV-resistant adhesive includes: uniformly dispersing each component of the UV-resistant adhesive layer in an organic solvent, with the total solid content controlled at 10%–25%. In one embodiment, the organic solvent includes butyl acetate.

[0078] In one embodiment, the heat-reducing adhesive layer comprises a hard monomer, a soft monomer, a functional monomer, an initiator, a curing agent, and foamed microspheres; the mass ratio of the hard monomer, soft monomer, functional monomer, initiator, curing agent, and foamed microspheres is (3-5):(20-35):(2-8):(0.1-1):(0.2-2):(1-5). This invention ensures the heat-reducing adhesive layer's effectiveness by using appropriate proportions of hard monomers, soft monomers, functional monomers, initiators, curing agents, and foamed microspheres.

[0079] In one embodiment, the hard monomer in the heat-resistant adhesive layer is selected from at least one of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and ethylene acrylate. In another embodiment, the hard monomer is selected from any one or a combination of at least two of the above, such as a combination of methyl methacrylate and ethyl methacrylate, or a combination of isopropyl methacrylate, n-butyl methacrylate, and ethylene acrylate.

[0080] In one embodiment, the soft monomer in the heat-resistant adhesive layer is selected from at least one of isooctyl acrylate, ethyl acrylate, and butyl acrylate. In another embodiment, the soft monomer is selected from any one of the above or a combination of at least two of them, such as a combination of isooctyl acrylate and ethyl acrylate.

[0081] In one embodiment, the functional monomer in the heat-resistant adhesive layer is selected from at least one of acrylic acid, methacrylic acid, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, acrylamide, and hydroxyacrylamide. In another embodiment, the functional monomer is selected from any one or at least two of the above, such as acrylic acid and methacrylic acid, or a combination of 2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, and acrylamide.

[0082] In one embodiment, the initiator in the heat-resistant adhesive layer is selected from benzoyl peroxide and / or azobisisobutyronitrile.

[0083] In one embodiment, the curing agent in the heat-resistant adhesive layer is selected from at least one of toluene diisocyanate, hexamethylene diisocyanate, and m-phenylenediamine epoxy resin. In another embodiment, the curing agent is selected from any one or at least two of the above, such as a combination of toluene diisocyanate and hexamethylene diisocyanate.

[0084] In one embodiment, the foamed microspheres are polystyrene microspheres with a particle size of 5–25 μm. In another embodiment, the initial foaming temperature is 140–155 °C.

[0085] In one embodiment, the method for preparing the heat-resistant adhesive includes: mixing a hard monomer, a soft monomer, a functional monomer, and an initiator with an organic solvent to obtain a first mixed system; heating the first mixed system to 70-85°C, maintaining it for 40-70 minutes, and then cooling it to room temperature to obtain a second mixed system; and mixing the second mixed system with a curing agent and foamed microspheres for 30-45 minutes to obtain the heat-resistant adhesive.

[0086] According to another aspect of the present invention, the present invention also relates to a method for preparing the copper foil composite as described above, comprising the following steps:

[0087] A copper layer is prepared on the surface of the cathode roller by electroplating;

[0088] A composite support is hot-pressed with the copper layer to peel the copper layer off the cathode roller. After anti-oxidation treatment, a copper foil composite is obtained.

[0089] The method for preparing the copper foil composite of the present invention is simple and easy to implement, which can reduce the defect rate of copper foil tearing and thus reduce the risk of copper foil breakage; the surface of the ultra-thin copper foil is free of glue and support layer residue, making it more suitable for use in the preparation of printed circuit boards.

[0090] The hot-pressing temperature is 100–120°C, for example, 105°C or 110°C. The cathode roller with the copper layer is at the bottom, and the composite support layer is at the top. After the two are bonded together, they are pressed together by a hot-pressing roller with a surface temperature of 100–120°C. The pressure of the hot-pressing is 4–6 kg.

[0091] In one embodiment, the electroplating is performed using an electroplating solution comprising copper salts, a conductive agent, an accelerator, a brightener, a leveling agent, and an inhibitor. The concentration of copper ions in the electroplating solution is 70–120 g / L, for example, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L, or 120 g / L. The concentration of the conductive agent is 85–150 g / L, for example, 85 g / L, 90 g / L, 95 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, or 150 g / L. The concentration of the accelerator is 10–80 ppm / L, for example, 10 ppm / L, 20 ppm / L, 30 ppm / L, 40 ppm / L, 50 ppm / L, 60 ppm / L, 70 ppm / L, or 80 ppm / L. The concentration of the brightener is 2–15 mL / L, for example, 2 mL / L, 3 mL / L, 5 mL / L, 8 mL / L, 10 mL / L, 15 mL / L, etc. The concentration of the leveling agent is 5–30 mL / L, for example, 5 mL / L, 10 mL / L, 15 mL / L, 20 mL / L, 25 mL / L, 30 mL / L, etc. The concentration of the inhibitor is 5–30 mL / L, for example, 5 mL / L, 10 mL / L, 15 mL / L, 20 mL / L, 30 mL / L, etc. This invention, by using appropriate concentrations of the above-mentioned components, ensures the effectiveness of obtaining a copper layer through electroplating.

[0092] In one embodiment, the copper salt comprises at least one selected from copper sulfate, copper nitrate, and copper chloride. In one embodiment, the conductive agent comprises at least one selected from sulfuric acid, nitric acid, hydrochloric acid, and acetic acid. In one embodiment, the accelerator comprises sodium polydithiopropanesulfonate. In one embodiment, the brightener comprises at least one selected from thiourea and sodium 3-mercapto-1-propanesulfonate. In one embodiment, the leveling agent comprises at least one selected from polyacrylamide, Janus Green, hydroxyethyl cellulose (HEC), sodium 3-mercapto-1-propanesulfonate, and sodium polydithiopropanesulfonate; in one embodiment, the inhibitor comprises at least one selected from polyethylene glycol, sodium N-(3-sulfopropyl)-saccharin, and hydroxyethyl cellulose.

[0093] In one embodiment, the reaction temperature of the electroplating solution is 45–60°C, for example, 45°C, 50°C, 55°C, or 60°C; the flow rate of the electroplating solution is 35–70 m³ / h. 3 / h; the current density of the electroplating is 25-40 A / dm. 2 For example, 25A / dm 2 30A / dm 2 35A / dm 2 40A / dm 2 In one embodiment, the surface roughness Ra of the cathode roller is 0.1–0.4 μm.

[0094] According to another aspect of the present invention, the present invention also relates to a method for preparing copper foil, comprising the following steps:

[0095] The adhesive layer in the copper foil composite is subjected to an adhesive-reducing treatment to separate the copper foil layer from the support layer, thereby obtaining copper foil; the copper foil composite is the copper foil composite described above, or the copper foil composite obtained by the method described above.

[0096] The method of this invention can reduce the defect rate of copper foil tearing, thereby reducing the risk of copper foil breakage; the ultra-thin copper foil surface has no glue or support layer residue, making it more suitable for use in the preparation of printed circuit boards; the support layer can be used as a carrier to improve the tensile strength of the film roll itself; the use of non-metallic support layer makes winding and transportation easier, and the winding radius can be increased several times, reducing the possibility of copper foil breakage during production; it has high production efficiency and large width; the support layer surface has less glue and ultra-thin metal layer residue, making it more conducive to recycling.

[0097] In one embodiment, the anti-tack treatment includes: irradiating the UV anti-tack adhesive layer with ultraviolet light, or heating the heat-resistant anti-tack adhesive layer.

[0098] In this invention, the working principle of the heat-reducing adhesive layer is as follows: when the external temperature reaches above the working temperature of the heat-reducing adhesive functional layer, the internal microspheres expand several times or even tens of times, causing foaming of the adhesive layer, making its surface rough, thereby reducing its adhesion and separating the two sides of the material. In one embodiment, the heating temperature for the anti-adhesion treatment is 180-195℃, such as 180℃, 185℃, 190℃, 195℃, etc., and the holding time is 10-18s, such as 10s, 12s, 15s, or 18s, etc.

[0099] In this invention, when ultraviolet light irradiates the surface of the anti-tack adhesive layer, it excites oxygen molecules in the UV-active substances and initiators, causing them to undergo an active chemical reaction. This reaction occurs on the main resin on the material surface, forming an organosilicon anti-tack film. In one embodiment, UV-LED lamp irradiation is used, and the ultraviolet irradiation conditions for the anti-tack treatment are: anti-tack wavelength of 390–400 nm and irradiation intensity of 1450–1550 mJ / cm². 2 .

[0100] In one embodiment, the copper foil composite and the insulating layer are hot-pressed at a temperature of 100–120°C and a pressure of 3–6 kg. Following this, the aforementioned de-adhesion treatment and peeling are performed. The peeling force between the support layer and the ultra-thin copper foil is much smaller than the peeling force between the insulating layer and the ultra-thin copper foil, resulting in a copper foil laminate.

[0101] According to another aspect of the present invention, the present invention also relates to a copper foil prepared by the method for preparing copper foil; the copper foil has a thickness of 0.8 to 2 μm, a tensile strength of 100 to 500 MPa, a surface gloss of 20 to 200, and a surface roughness Ra value of 0.1 to 0.8 μm.

[0102] In one embodiment, the copper foil has a first surface and a second surface, the first surface has a gloss level of 40 to 150, the second surface has a gloss level of 20 to 120, and the gloss level of the first surface is greater than or equal to the gloss level of the second surface; the roughness Ra1 of the first surface is 0.2 to 0.3, the roughness Ra2 of the second surface is 0.3 to 0.5, and Ra1 ≤ Ra2.

[0103] According to another aspect of the invention, the invention also relates to a printed circuit board comprising copper foil prepared by the aforementioned method for preparing copper foil.

[0104] The following explanation, combined with specific embodiments and comparative examples, further illustrates the point.

[0105] Example 1

[0106] The method for preparing copper foil composites includes the following steps:

[0107] (a) A copper layer was prepared by electroplating. The electroplating solution consisted of copper sulfate, sulfuric acid, hydrochloric acid, sodium polydithiopropanesulfonate, polyacrylamide, hydroxyethyl cellulose, and deionized water. The concentrations of copper sulfate, sulfuric acid, hydrochloric acid, sodium polydithiopropanesulfonate, polyacrylamide, and hydroxyethyl cellulose were 90 g / L, 100 g / L, 10 ppm / L, 8 ml / L, 10 ml / L, and 10 ml / L, respectively. A titanium plate coated with an iridium-tantalum oxide layer was used as the anode and the titanium plate as the cathode. The electroplating solution temperature was 49°C, and the flow rate was 50 m³ / L. 3 / h, the surface roughness Ra value of the cathode roller is 0.18;

[0108] (b) A composite support is used to hot-press the copper layer together at a temperature of 110°C and a pressure of 4.5 kg. The copper layer is then peeled off from the cathode roller and subjected to anti-oxidation treatment to obtain a copper foil composite, as shown in the schematic diagram below. Figure 1 As shown, the composite support includes a support layer 1, a non-adhesive layer 2, and a copper foil layer 3. The non-adhesive layer 2 is located between the support layer 1 and the copper foil layer 3. The support layer is modified PET. The non-adhesive layer used is a heat-resistant non-adhesive layer, which is composed of hard monomers, soft monomers, functional monomers, initiators, curing agents, and foamed microspheres. The mass ratio of the hard monomers, soft monomers, functional monomers, initiators, curing agents, and foamed microspheres is 3:30:5:0.5:1:1. The hard monomer is ethyl methacrylate, the soft monomer is ethyl acrylate, the functional monomer is 2-hydroxypropyl acrylate, the initiator is benzoyl peroxide, and the curing agent is hexamethylenetetramine. Isocyanate, foamed microspheres are polystyrene microspheres; the preparation method of the anti-tack adhesive includes: at room temperature, dissolving 3 parts of ethyl methacrylate, 30 parts of ethyl acrylate, 5 parts of 2-hydroxypropyl acrylate, and 0.5 parts of benzoyl peroxide in a mixed solution of toluene and ethyl acetate, with a volume ratio of toluene to ethyl acetate of 1:4 and a solid-to-liquid mass ratio of 4:5, uniformly mixing, raising the temperature to 80°C, maintaining it for 1 hour, and cooling it to room temperature to obtain an acrylic mixture; adding 1 part of hexamethylene diisocyanate and 1 part of polystyrene microspheres to the acrylic mixture, shaking for 40 minutes to obtain the heat-resistant anti-tack adhesive.

[0109] The thickness is 10μm, the peel strength of the adhesive is 5N / cm, and the overall tensile strength of the copper foil composite is 500MPa. After heating on a hot plate at 175℃ for 1 hour, neither the support layer nor the copper foil deformed.

[0110] The method for preparing copper foil includes: subjecting the anti-adhesive layer in the copper foil composite obtained above to anti-adhesion treatment at a temperature of 180℃ and a holding time of 15s; separating the copper foil layer from the support layer to obtain copper foil. After anti-adhesion treatment, the composite product exhibits a peel strength of 0.1 N / cm, indicating that the copper foil can be easily separated from the support layer without breakage. The prepared ultrathin copper foil has a thickness of 1.2 μm, a tensile strength of 160 MPa, a gloss level of 100, an Ra value of 0.2, a thickness of 25 μm, and a temperature resistance of 220℃.

[0111] Example 2

[0112] The method for preparing copper foil composites includes the following steps:

[0113] (a) A copper layer was prepared by electroplating. The electroplating solution consisted of copper sulfate, sulfuric acid, hydrochloric acid, sodium polydithiopropanesulfonate, polyacrylamide, hydroxyethyl cellulose, and deionized water, with the following concentrations: copper sulfate 90 g / L, sulfuric acid 100 g / L, hydrochloric acid 10 ppm / L, sodium polydithiopropanesulfonate 8 ml / L, polyacrylamide 10 ml / L, and hydroxyethyl cellulose 10 ml / L. A titanium plate coated with an iridium-tantalum oxide layer was used as the anode and the titanium plate as the cathode. The electroplating solution temperature was 50 °C, and the flow rate was 50 m³ / L. 3 / h, the surface roughness Ra value of the cathode roller is 0.2;

[0114] (b) A composite support is used to bond the copper layer together. The hot-pressing temperature is 110°C and the hot-pressing pressure is 4.5 kg. The copper layer is then peeled off from the cathode roller and subjected to anti-oxidation treatment to obtain a copper foil composite. The structural schematic diagram is shown below. Figure 1 As shown, the composite support includes a support layer 1, an anti-adhesion layer 2, and a copper foil layer 3. The anti-adhesion layer 2 is located between the support layer 1 and the copper foil layer 3. The anti-adhesion adhesive is a UV anti-adhesion adhesive with a thickness of 10 μm and a peel strength of 5 N / cm.

[0115] The UV-resistant adhesive is composed of a main resin, UV active material, curing agent, and photoinitiator, with a mass ratio of 90:5:4:1. The main resin is ethyl methacrylate, the UV active material is trimethylolpropane triacrylate, the curing agent is polytoluene diisocyanate trimer, and the photoinitiator is 2,4,6-trimethylbenzoyl diphenylphosphine oxide. The above components of the UV-resistant adhesive are dissolved in butyl acetate, with the solid content controlled at 20%. After uniform stirring, the UV-resistant adhesive is applied to the surface of the support layer using a roller coating method.

[0116] The support layer used is PI with a thickness of 25μm, and the overall tensile strength of the copper foil composite is 850MPa.

[0117] The method for preparing copper foil includes: performing a de-adhesion treatment on the de-adhesion adhesive layer in the copper foil composite obtained above, and irradiating it with a UV-LED lamp at a wavelength of 395nm and an irradiation intensity of 1500mj / cm². 2 The peel strength is 0.05 N / cm; the copper foil layer is separated from the support layer to obtain copper foil; the prepared ultrathin copper foil has a thickness of 1.2 μm, a tensile strength of 160 MPa, a brightness of 100, and an Ra value of 0.2.

[0118] Example 3

[0119] The method for preparing copper foil composites includes the following steps:

[0120] (a) A copper layer was prepared by electroplating. The electroplating solution consisted of copper sulfate, sulfuric acid, hydrochloric acid, sodium polydithiopropanesulfonate, polyacrylamide, hydroxyethyl cellulose, and deionized water, with the following concentrations: copper sulfate 85 g / L, sulfuric acid 105 g / L, hydrochloric acid 12 ppm / L, sodium polydithiopropanesulfonate 10 ml / L, polyacrylamide 12 ml / L, and hydroxyethyl cellulose 10 ml / L. A titanium plate coated with an iridium-tantalum oxide layer was used as the anode and the titanium plate as the cathode. The electroplating solution temperature was 52°C, and the flow rate was 45 m³ / L. 3 / h, the Ra value of the cathode roller surface is 0.3;

[0121] (b) A composite support is used to bond the copper layer to the cathode roller. The copper layer is then peeled off and subjected to an anti-oxidation treatment to obtain a copper foil composite. A schematic diagram of the structure is shown below. Figure 1 As shown, the composite support includes a support layer 1, an anti-adhesion layer 2, and a copper foil layer 3. The anti-adhesion layer 2 is located between the support layer 1 and the copper foil layer 3. The anti-adhesion layer used is a heat-resistant anti-adhesion, and the composition of the heat-resistant anti-adhesion is the same as in Example 1. The thickness is 5 μm. The support layer used is aluminum foil. The peel strength of the adhesive layer is 4 N / cm.

[0122] A method for preparing copper foil includes: subjecting the anti-adhesion layer in the copper foil composite obtained above to anti-adhesion treatment at a temperature of 190℃ and a holding time of 10s, with a peel strength of 0.04N / cm; separating the copper foil layer from the support layer to obtain copper foil. The prepared ultrathin copper foil has a thickness of 1.4μm, a tensile strength of 180MPa, a gloss level of 120, an Ra value of 0.25, and a thickness of 50μm.

[0123] Example 4

[0124] The preparation method of copper foil is the same as in Example 2, except that the main resin is isobutyl methacrylate, the UV active material is neopentyl tert-triacrylate, the photoinitiator is an acylphosphine oxide compound, and the mass ratio of the main resin, UV active material, curing agent and photoinitiator is 88:7:2:3.

[0125] In this embodiment, the peel strength of the adhesive is 4.5 N / cm, and the peel strength after UV irradiation to reduce tack is 0.03 N / cm.

[0126] Example 5

[0127] The method for preparing copper foil is the same as in Example 1, except that the hard monomer is isobutyl methacrylate, the soft monomer is butyl acrylate, the functional monomer is 2-hydroxypropyl acrylate, the initiator is azobisisobutyronitrile, the curing agent is toluene diisocyanate, and the mass ratio of hard monomer, soft monomer, functional monomer, initiator, curing agent and foamed microspheres is 5:25:3:1:1.5:2.

[0128] In this embodiment, the peel strength of the adhesive is 0.9 N / cm.

[0129] Comparative Example 1

[0130] In this comparative example, except for the de-adhesion temperature of 175℃, the holding time of 20s, and the peel strength test of 1N / cm, all other conditions were the same as in Example 1. The copper foil cracked and did not peel off completely.

[0131] Comparative Example 2

[0132] The preparation method of copper foil is the same as in Example 2, except that the mass ratio of main resin, UV active material, curing agent and photoinitiator is 87:0.5:6:6.5.

[0133] In this comparative example, the peel strength was 4 N / cm, and the peel strength after UV irradiation was 0.15 N. The copper foil cracked and did not peel completely.

[0134] Comparative Example 3

[0135] The preparation method of copper foil is the same as in Example 1, except that the mass ratio of hard monomer, soft monomer, functional monomer, initiator, curing agent and foamed microspheres is 3:40:1:2:5:0.5.

[0136] In this comparative example, the initial peel strength was 6 N / cm, and after heating, the peel strength was 0.14 N / cm, the copper foil cracked, and there was no complete peel.

[0137] The peel strength test method involved in the embodiments and comparative examples of this invention is as follows: The sample is cut into strips 15mm wide and 100mm long. One end of 3M tape is attached to the surface of the copper foil, and the sample is compacted with a 2kg roller. Then, a tensile testing machine is used to perform a peel test on the sample. The distance between the upper and lower clamps of the tensile testing machine is 5cm. The upper clamp holds one end of the test sample, and the lower clamp holds the other end of the 3M tape. The sample to be tested is finally shaped like a herringbone.

[0138] In summary, the copper foil composite of the present invention uses a support layer as a carrier, which can improve the tensile strength of the film roll itself and reduce the possibility of breakage during copper foil production; the anti-adhesion adhesive layer facilitates the separation of the copper foil layer from the support layer in the later stage, and ensures that there is no glue or support layer residue on the surface of the copper foil layer. The copper foil obtained by the method of the present invention has excellent mechanical properties.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A copper foil composite, characterized in that, It includes a copper foil layer and a composite support; the composite support includes a support layer and an anti-adhesion layer, the anti-adhesion layer being located between the support layer and the copper foil layer; the support layer includes an insulating material layer and / or a metal material layer.

2. The copper foil composite according to claim 1, characterized in that, It includes at least one of the following features (1) to (7): (1) The tensile strength of the copper foil composite is 150-1500 MPa, the peel strength is 3-8 N / cm, the surface gloss is 20-200, and the surface roughness Ra value is 0.1-0.8 μm; (2) The insulating material layer is made of at least one of PI, modified PET, PFA and PDMS; (3) The material of the metal material layer includes at least one of copper, titanium, aluminum, stainless steel and tin; (4) The thickness of the support layer is 5 to 50 μm; (5) The adhesive layer includes a UV adhesive layer or a heat-resistant adhesive layer; (6) The thickness of the adhesive layer is 3 to 25 μm. (7) After the copper foil composite is subjected to anti-adhesion treatment, the copper foil peel strength is 0.04 N / cm to 0.1 N / cm, and the anti-adhesion treatment includes at least one of UV irradiation and heat treatment.

3. The copper foil composite according to claim 2, characterized in that, It includes at least one of the following features (1) to (5): (1) The UV-resistant adhesive layer comprises a main resin, a UV active substance, a curing agent and a photoinitiator; the mass ratio of the main resin, the UV active substance, the curing agent and the photoinitiator is (88-93):(1-8):(0.5-5):(1-3); (2) In the UV adhesive layer, the main resin is selected from at least one of methyl acrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate and decyl methacrylate. (3) In the UV-resistant adhesive layer, the UV active material is selected from at least one of vinyl aromatic polyurethane acrylate oligomer, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, neopentyl terephthalate triacrylate and polydipentaerythritol hexaacrylate. (4) In the UV adhesive layer, the curing agent is selected from at least one of polyisocyanate compounds, epoxy compounds, aziridine compounds and metal chelate compounds; (5) In the UV adhesive layer, the photoinitiator is selected from at least one of benzoin compound, acetophenone compound, thioxanone compound, peroxide compound and acylphosphine oxide compound.

4. The copper foil composite according to claim 2, characterized in that, It includes at least one of the following features (1) to (6): (1) The heat-resistant adhesive layer comprises hard monomers, soft monomers, functional monomers, initiators, curing agents, and foamed microspheres; the mass ratio of the hard monomers, soft monomers, functional monomers, initiators, curing agents, and foamed microspheres is (3-5):(20-35):(2-8):(0.1-1):(0.2-2):(1-5); (2) In the heat-resistant adhesive layer, the hard monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate and ethylene acrylate; (3) In the heat-resistant adhesive layer, the soft monomer is selected from at least one of isooctyl acrylate, ethyl acrylate and butyl acrylate; (4) In the heat-resistant adhesive layer, the functional monomer is selected from at least one of acrylic acid, methacrylic acid, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, acrylamide and hydroxyacrylamide; (5) In the heat-resistant adhesive layer, the initiator is selected from benzoyl peroxide and / or azobisisobutyronitrile; (6) In the heat-resistant adhesive layer, the curing agent is selected from at least one of toluene diisocyanate, hexamethylene diisocyanate and m-phenylenediamine epoxy resin.

5. The method for preparing the copper foil composite as described in any one of claims 1 to 4, characterized in that, Includes the following steps: A copper layer is prepared on the surface of the cathode roller by electroplating; A composite support is hot-pressed with the copper layer to peel the copper layer off the cathode roller. After anti-oxidation treatment, a copper foil composite is obtained.

6. The method for preparing the copper foil composite according to claim 5, characterized in that, It includes at least one of the following features (1) to (11): (1) The electroplating uses an electroplating solution, which includes copper salt, conductive agent, accelerator, brightener, leveling agent and inhibitor; (2) The reaction temperature of the electroplating solution is 45–60℃, and the flow rate of the electroplating solution is 35–70 m³ / h. 3 / h; the current density of the electroplating is 25-40 A / dm. 2 ; (3) The surface roughness Ra of the cathode roller is 0.1 to 0.4 μm; (4) In the electroplating solution, the concentration of copper ions is 70-120 g / L, the concentration of conductive agent is 85-150 g / L, the concentration of accelerator is 10-80 ppm / L, the concentration of brightener is 2-15 mL / L, the concentration of leveling agent is 5-30 mL / L, and the concentration of inhibitor is 5-30 mL / L. (5) The copper salt includes at least one of copper sulfate, copper nitrate and copper chloride; (6) The conductive agent includes at least one of sulfuric acid, nitric acid, hydrochloric acid and acetic acid; (7) The accelerator includes sodium polydithiopropanesulfonate; (8) The brightener includes at least one of thiourea and sodium 3-mercapto-1-propanesulfonate; (9) The leveling agent includes at least one of polyacrylamide, Janus Green, hydroxyethyl cellulose (HEC), sodium 3-mercapto-1-propanesulfonate and sodium polydithiopropanesulfonate; (10) The inhibitor comprises at least one of polyethylene glycol, sodium N-(3-sulfopropyl)-saccharin and hydroxyethyl cellulose; (11) The temperature of the hot-pressing composite is 100-120℃, and the pressure of the hot-pressing composite is 4-6kg.

7. A method for preparing copper foil, characterized in that, Includes the following steps: The adhesive layer in the copper foil composite is subjected to an adhesive-reducing treatment to separate the copper foil layer from the support layer, thereby obtaining copper foil; the copper foil composite is the copper foil composite of any one of claims 1 to 4, or the copper foil composite obtained by the preparation method of the copper foil composite of any one of claims 5 to 6.

8. The method for preparing copper foil according to claim 7, characterized in that, It includes at least one of the following features (1) to (4): (1) The anti-tack treatment includes: irradiating the UV anti-tack adhesive layer with ultraviolet light, or heating the heat-resistant anti-tack adhesive layer; (2) The heating temperature for the viscosity reduction treatment is 180-195℃, and the holding time is 10-18s; (3) The ultraviolet irradiation conditions for the viscosity reduction treatment are: viscosity reduction wavelength of 390-400 nm, and irradiation intensity of 1450-1550 mJ / cm. 2 ; (4) The copper foil composite and the insulating layer are hot-pressed, and then the aforementioned de-adhesion treatment and peeling are performed to obtain the copper foil laminate.

9. A copper foil, characterized in that, The copper foil is prepared by the method described in any one of claims 7 to 8; the copper foil has a thickness of 0.8 to 2 μm, a tensile strength of 100 to 500 MPa, a surface gloss of 20 to 200, and a surface roughness Ra value of 0.1 to 0.8 μm.

10. A printed circuit board, characterized in that, The copper foil prepared by the method described in any one of claims 7 to 8.

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