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CN-121988610-A - PET (polyethylene terephthalate) composite rolled copper foil and manufacturing method thereof

CN121988610ACN 121988610 ACN121988610 ACN 121988610ACN-121988610-A

Abstract

The invention relates to a PET composite rolled copper foil and a manufacturing method thereof. The PET composite rolled copper foil comprises a rolled copper foil substrate and a polyethylene terephthalate (PET) layer compounded on one side of the rolled copper foil substrate. The rolled copper foil base material is obtained by multi-pass cold rolling of copper blanks, the total rolling reduction rate of the cold rolling is not lower than 97%, differential rolling is carried out in at least part of cold rolling passes, the linear speed ratio of an upper working roller to a lower working roller is 1.05-1.30, and in the multi-pass cold rolling process, at least one sectional annealing treatment is carried out after the accumulated rolling reduction rate reaches 30% -60%. The sectional annealing treatment satisfies the following judgment condition of 'inhibiting complete recrystallization', wherein (i) the volume fraction of recrystallization measured by EBSD or metallographic statistics according to RD-ND section after sectional annealing is not higher than 30%, preferably not higher than 15%, and (ii) the Vickers hardness reduction amplitude DeltaHV of the rolled copper foil base material after sectional annealing is 10-35 HV relative to that before sectional annealing. After the process treatment, the rolled copper foil substrate has an elongated grain structure which is continuously distributed in a fiber manner in the rolling direction, and the rolled copper foil substrate meets the conditions that the grain length-width ratio AR is more than or equal to 12, the rolling texture fraction Ftex is more than or equal to 55 percent and the dislocation density rho is more than or equal to 1X 1014 m-2.

Inventors

  • SHEN XIAOXIA
  • SHEN GUOZHONG

Assignees

  • 杭州巨力绝缘材料有限公司

Dates

Publication Date
20260508
Application Date
20260319

Claims (20)

  1. 1. A PET composite rolled copper foil is characterized by comprising a rolled copper foil substrate and a polyethylene terephthalate (PET) layer compounded on one surface of the rolled copper foil substrate, wherein the rolled copper foil substrate is obtained by cooperatively controlling a process of carrying out multi-pass cold rolling on a copper blank, the total reduction rate of cold rolling is not lower than 97%, differential rolling is carried out in at least part of cold rolling passes, the linear speed ratio of an upper working roll to a lower working roll is 1.05-1.30, and in the multi-pass cold rolling process, after the cumulative reduction rate reaches 30% -60%, at least one sectional annealing treatment is carried out, the sectional annealing treatment meets the judgment condition of 'inhibiting complete recrystallization', the volume fraction of recrystallization is not higher than 30%, preferably not higher than 15% as measured by EBSD or metallographic statistics according to RD-ND section, the reduction rate of the rolled copper foil substrate is 10-HV in the rolling direction after the process, the rolled copper foil substrate is in a continuous fiber-shaped rolled structure after the process, and the grain density of the rolled copper foil is 5m & gtoreq 1-8664 m & gtoreq 2.
  2. 2. The PET composite rolled copper foil according to claim 1, wherein the grain structure of the rolled copper foil base material is continuously fibrillated in a rolling direction, and elongated grain regions continuously distributed in the rolling direction are visible when seen in RD-ND section.
  3. 3. The PET composite rolled copper foil according to claim 1 or 2, wherein the rolled copper foil substrate has a grain aspect ratio AR not less than 15, preferably not less than 18.
  4. 4. The PET composite rolled copper foil according to claim 1 to 3, wherein the rolled copper foil substrate has a rolled texture score Ftex≥65%, the rolled texture comprising one or more orientations of beta fibers.
  5. 5. The PET composite rolled copper foil according to claim 1 to 4, wherein the rolled copper foil substrate has a dislocation density ρ of 2X 101 4 –1×10¹ 5 m-2.
  6. 6. The PET composite rolled copper foil according to claim 1 to 5, wherein the recrystallised volume fraction of the rolled copper foil substrate is not higher than 20%, preferably not higher than 15%.
  7. 7. The PET composite rolled copper foil according to any one of claims 1 to 6, wherein a linear velocity ratio of upper and lower work rolls in the differential rolling is 1.10 to 1.20.
  8. 8. The PET composite rolled copper foil according to claim 1 to 7, wherein the differential rolling pass is 20% -60% of the total cold rolling pass or is located in the region of the last 30% -50% of the total cold rolling reduction.
  9. 9. The PET composite rolled copper foil according to claim 1 to 8, wherein the sectional annealing treatment reduces the Vickers hardness of the rolled copper foil base material by 15 to 30 HV.
  10. 10. The PET composite rolled copper foil according to claim 1 to 9, wherein the PET layer is compounded with the rolled copper foil substrate through a polyester-based intermediate adhesive layer provided between the PET layer and the rolled copper foil substrate.
  11. 11. The PET composite calendered copper foil of claim 10 wherein the intermediate tie layer is a copolyester or modified polyester thermoplastic polymer layer.
  12. 12. The PET composite rolled copper foil according to claim 10 or 11, wherein the thickness of the intermediate adhesive layer is 1-20. Mu.m, preferably 3-12. Mu.m.
  13. 13. The PET composite rolled copper foil according to claim 1 to 12, wherein the rolled copper foil substrate has a micro-roughened surface on a side compounded with the PET layer.
  14. 14. The PET composite rolled copper foil according to claim 1 to 13, wherein the rolled copper foil substrate is subjected to one or more of a plasma treatment, a corona treatment or a UV-ozone treatment surface activation treatment prior to the compounding of the PET layer.
  15. 15. The PET composite rolled copper foil according to any one of claims 1 to 14, wherein the PET composite rolled copper foil is used for an electromagnetic shielding layer or a flexible signal transmission structure of a high-speed cable.
  16. 16. The manufacturing method of the PET composite rolled copper foil is characterized by comprising the following steps of: a) Providing a copper blank, and carrying out multi-pass cold rolling on the copper blank to gradually thin the copper foil, wherein the total rolling reduction of the cold rolling is not less than 97%; b) In the multi-pass cold rolling process, differential rolling is carried out in at least a part of cold rolling passes, so that the linear speed ratio of the upper working roller to the lower working roller is 1.05-1.30; c) In the multi-pass cold rolling process, after the cumulative rolling reduction reaches 30% -60%, carrying out at least one sectional annealing treatment on the copper foil, and enabling the sectional annealing treatment to meet the judgment condition of 'inhibiting complete recrystallization', wherein the volume fraction of recrystallization is not higher than 30%, preferably not higher than 15% as measured by EBSD or metallographic statistics according to RD-ND section after the sectional annealing, and the Vickers hardness reduction amplitude DeltaHV of the rolled copper foil is 10-35 HV after the sectional annealing relative to that before the sectional annealing; d) Continuing cold rolling after the sectional annealing treatment; e) Compounding a polyethylene terephthalate (PET) layer on one surface of the rolled copper foil substrate to obtain a PET composite rolled copper foil; wherein the rolled copper foil base material obtained through the steps a) to d) satisfies that the aspect ratio AR of crystal grains is more than or equal to 12, the rolling texture fraction Ftex is more than or equal to 55 percent and the dislocation density rho is more than or equal to 1 multiplied by 101 4 m < -2 >.
  17. 17. The method of producing a PET composite rolled copper foil according to claim 16, wherein a linear speed ratio of the upper and lower work rolls of the differential rolling is 1.10 to 1.20.
  18. 18. The method of producing a PET composite rolled copper foil according to claim 16 or 17, wherein the differential rolling pass is 20% to 60% of the total cold rolling pass or is located in the range of the last 30% to 50% of the total cold rolling reduction.
  19. 19. The method for producing a PET composite rolled copper foil according to any one of claims 16 to 18, wherein the step annealing treatment makes the recrystallized volume fraction of the rolled copper foil not higher than 20%, preferably not higher than 15%.
  20. 20. The method for producing a PET composite rolled copper foil according to any one of claims 16 to 19, wherein the sectional annealing treatment reduces the Vickers hardness of the rolled copper foil by 15 to 30 HV as a value of ΔHV.

Description

PET (polyethylene terephthalate) composite rolled copper foil and manufacturing method thereof Technical Field The invention relates to a PET composite rolled copper foil with a continuous fiber elongation grain structure and a manufacturing method thereof, in particular to a PET composite rolled copper foil which constructs the continuous elongation grain structure in the rolled copper foil through the cooperative control of differential rolling and segmented annealing for inhibiting complete recrystallization and is applied to a PET composite system and a manufacturing method thereof, which can inhibit crack initiation of the metal foil in a folding edge and a lap joint area in a high-speed coating process on the premise of not reducing the coating line speed and not increasing the thickness of the metal foil, and is mainly used for manufacturing the rolled copper foil for 224G and 448G high-speed cables, and belongs to the technical field of high-speed data transmission composite metal foil materials. The PET composite rolled copper foil can be applied to application scenes such as high-speed cables, electromagnetic shielding layers, flexible signal transmission structures and the like with requirements on folding endurance and interface reliability. Background Rolled copper foil is widely used in the fields of high-speed cables, electromagnetic shielding and flexible electronics because of its excellent conductivity and ductility. With the development of high-speed signal transmission and flexible applications, copper foil is generally required to be used in combination with polymer insulation materials to meet the requirements of electromagnetic performance and mechanical performance at the same time. Polyethylene terephthalate (PET) is widely used as a composite insulating layer of copper foil because it has good mechanical strength, heat resistance and dielectric properties. However, in practical application, the composite structure of PET and copper foil is prone to warping or peeling at the interface under repeated bending, thermal cycle or long-term service conditions, and the product reliability is seriously affected. In the prior art, in order to improve the bonding performance between PET and copper foil, the following technical means are generally adopted: 1) Setting a reaction type base coat or an adhesion promoter on the surface of the copper foil; 2) Introducing a copolyester or modified polyester bonding layer between the PET and the copper foil; 3) Roughening, corona or plasma activating treatment is carried out on the surface of the copper foil to improve mechanical embedding and wettability of the interface. The above technical solution is mainly focused on modification of interface materials or surface states, and although the initial peel strength can be improved to a certain extent, failure may still occur due to interface shear stress concentration under the action of repeated bending or thermal stress. In addition, the prior art generally treats copper foil as a homogeneous carrier, and concerns about the relationship between the internal grain structure of the copper foil and the long-term stability of the composite interface are relatively inadequate. Therefore, there is still a need to provide a new technical solution to improve the interfacial stability of the PET and copper foil composite structure under the conditions of repeated bending and thermal cycle from the material internal structure level. Disclosure of Invention The invention aims to solve the problems, and aims to provide a PET composite rolled copper foil and a manufacturing method thereof, wherein an elongated grain structure which is continuously fibrotically distributed along a rolling direction is built in the rolled copper foil, so that the interface stress state of a PET layer and the rolled copper foil after being compounded is improved, and the folding endurance and the bonding stability of a composite interface are improved. The invention further aims to realize the continuity and the reservation of the elongated grain structure through the cooperative control of differential rolling and segmented annealing for inhibiting complete recrystallization under the condition of high total rolling reduction, ensure that the obtained PET composite rolled copper foil shows better interface bonding stability under the test condition described in the specification, and provide a manufacturing method with clear process path and industrial implementation. The invention is characterized in that, unlike the traditional thought of improving adhesive force only from composite interface materials or surface states, from the internal grain structure of a rolled copper foil, an elongated grain structure distributed along the rolling direction in continuous fibrosis is constructed under the condition of high total rolling reduction through the cooperative control of differential rolling and segmented annealing for inhibiting c