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CN-122011705-A - PET (polyethylene terephthalate) base film for composite current collector and preparation method thereof

CN122011705ACN 122011705 ACN122011705 ACN 122011705ACN-122011705-A

Abstract

The scheme relates to a PET (polyethylene terephthalate) base film for a composite current collector and a preparation method thereof, wherein the PET base film comprises PET slices, modified PET, modified silicon dioxide, a lubricant and an antioxidant, the modified PET is prepared by esterifying and polycondensing terephthalic acid, ethylene glycol and imidazole glycol-containing monomers, and the imidazole glycol-containing monomers are prepared from the compound A shown in the specification Compound B of formula (I) The modified silicon dioxide is obtained by ring-opening grafting reaction of the treated nano silicon dioxide particles and a compound A by using a silane coupling agent KH 560. According to the invention, the imidazole group-containing bi-component diol monomer is introduced into the PET main chain, and the compound A is grafted on the surface of the nano silicon dioxide, so that double enrichment of the imidazole group on the base film body and the surface is realized, the mechanical modulus and the heat resistance of the base film are enhanced, the base film is not easy to deform in a high-temperature coating environment, and the problem that a metal layer is easy to fall off is effectively solved.

Inventors

  • ZHUANG ZHI
  • WANG YONGJUN
  • XIA JINGJING
  • WANG RUNXIAO
  • WANG FENG

Assignees

  • 扬州博恒新能源材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260410

Claims (7)

  1. 1. The PET base film for the composite current collector is characterized by comprising, by weight, 70-90 parts of PET slices, 10-30 parts of modified PET, 4-8 parts of modified silicon dioxide, 0.5-1 part of lubricant and 0.2-0.8 part of antioxidant; The modified PET is prepared from terephthalic acid, ethylene glycol and imidazole-containing diol monomers through esterification and polycondensation, wherein the imidazole-containing diol monomers consist of a compound A shown in a formula 1) and a compound B shown in a formula 2); Formula 1) formula 2) The modified silicon dioxide is obtained by ring-opening grafting reaction of the treated nano silicon dioxide particles and a compound A by using a silane coupling agent KH 560.
  2. 2. The PET base film for the composite current collector according to claim 1, wherein the molar ratio of terephthalic acid to ethylene glycol to imidazole-containing diol monomer in the preparation process of the modified PET is 1:1.0-1.2:0.05-0.3, and the molar ratio of the compound A to the compound B in the imidazole-containing diol monomer is 0.3-0.5:0.5-0.7.
  3. 3. The PET base film for a composite current collector according to claim 1, wherein the modified PET is prepared as follows: Adding terephthalic acid, ethylene glycol and imidazole glycol monomers into a reaction kettle, adding a catalytic amount of ethylene glycol antimony, and carrying out esterification reaction under the protection of nitrogen, wherein the esterification temperature is 250-260 ℃ and the pressure is 0.3-0.4 MPa; After the esterification reaction is finished, adding a stabilizer triphenyl phosphite and a polycondensation catalyst antimonous oxide into a reaction kettle, synchronously vacuumizing, heating to 250-270 ℃ for reacting for 2-3 hours, and cooling and blanking to obtain the catalyst.
  4. 4. The PET base film for a composite current collector according to claim 1, wherein the modified silica is prepared as follows: Dispersing nano silicon dioxide particles in absolute ethyl alcohol by ultrasonic, adding a silane coupling agent KH560, raising the temperature, carrying out reflux reaction for 8 hours, centrifuging after the reaction is finished, washing with absolute ethyl alcohol, drying for standby, dispersing the dried solid in absolute ethyl alcohol again, adding a compound A, stirring and reacting for 8-12 hours at 70-90 ℃, centrifuging after the reaction is finished, washing with ethanol for 3-5 times, and vacuum drying at 60-80 ℃ to constant weight to obtain the imidazolyl functionalized modified silicon dioxide.
  5. 5. The PET base film for a composite current collector according to claim 1, wherein the lubricant is at least one of ethylene bis stearamide, pentaerythritol stearate, butyl stearate.
  6. 6. The PET base film for a composite current collector according to claim 1, wherein the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.
  7. 7. The method for preparing a PET base film for a composite current collector according to any one of claims 1 to 6, comprising the steps of: 1) Weighing and metering PET slices, modified PET, modified silicon dioxide, a lubricant and an antioxidant, putting the PET slices, the modified PET, the modified silicon dioxide, the lubricant and the antioxidant into a high-speed mixer to be uniformly mixed to obtain a mixed material, then feeding the mixed material into a double-screw extruder, melting, blending and extruding the mixed material at 260-280 ℃, and casting the mixed material onto a cooling roller through a die head to obtain a cast sheet; 2) Carrying out biaxial stretching on the cast sheet, carrying out longitudinal stretching at the stretching temperature of 95-105 ℃ and the stretching multiplying power of 2.5-3.5 times, and then carrying out transverse stretching at the stretching temperature of 100-120 ℃ and the stretching multiplying power of 3.0-4.0 times; 3) And (3) performing heat setting treatment on the biaxially stretched film at 200-230 ℃, cooling, traction and rolling.

Description

PET (polyethylene terephthalate) base film for composite current collector and preparation method thereof Technical Field The invention relates to the technical field of composite current collector base films, in particular to a PET base film for a composite current collector and a preparation method thereof. Background The composite current collector is a novel material developed by replacing the traditional anode current collector electrolytic copper foil or anode current collector calendaring aluminum foil, and is a sandwich structure formed by depositing a metal layer on the surface of an ultrathin organic polymer film to form a metal layer, an organic film layer and a metal layer, so that the consumption of the metal material can be effectively reduced, the dead weight is lightened, and the stability of the battery is improved. The organic thin film layer in the composite current collector plays a critical role in its performance and is typically made of polyethylene terephthalate (PET), polypropylene (PP) or Polyimide (PI). PET is a colorless transparent and glossy film, has higher hardness and toughness, excellent puncture resistance and friction resistance and good optical performance, and can be applied to various fields such as composite current collector films, electrical insulating films, release films, capacitance films, polaroid protection films, packaging films and the like. However, different chemical or physical modifications of PET are required for different application fields to adapt to different performance requirements. For the composite current collector base film, as the composite current collector is formed by stacking metal atoms on an organic base film layer through coating processes such as vacuum evaporation, magnetron sputtering, PVD vacuum sputtering and the like, the heat resistance and mechanical strength of the base material are required to be high. If the PET film is directly used as a base material, the strength is often insufficient, and the coating is also easily peeled off. The PET base film has relatively low glass transition temperature, is easy to deform in a high-temperature coating environment, and has weak bonding force between the surface of the PET base film and the metal layer, so that the metal layer is easily peeled off from the surface of the base material due to thermal stress. Disclosure of Invention Aiming at the defects in the prior art, the invention introduces the diol compound containing the imidazolyl, partially polymerized in situ in PET, partially grafted with nano silicon dioxide, and then mixed with PET main material to prepare the film, thereby effectively improving the bonding force between the PET main material and the metal layer. In order to achieve the above purpose, the present invention provides the following technical solutions: The PET base film for the composite current collector comprises, by weight, 70-90 parts of PET slices, 10-30 parts of modified PET, 4-8 parts of modified silicon dioxide, 0.5-1 part of lubricant and 0.2-0.8 part of antioxidant; The modified PET is prepared from terephthalic acid, ethylene glycol and imidazole-containing diol monomers through esterification and polycondensation, wherein the imidazole-containing diol monomers consist of a compound A shown in a formula 1) and a compound B shown in a formula 2); ; Formula 1) formula 2) The modified silicon dioxide is obtained by ring-opening grafting reaction of the treated nano silicon dioxide particles and a compound A by using a silane coupling agent KH 560. Further, in the preparation process of the modified PET, the molar ratio of terephthalic acid to ethylene glycol to imidazole-containing diol monomers is 1:1.0-1.2:0.05-0.3, and the molar ratio of the compound A to the compound B in the imidazole-containing diol monomers is 0.3-0.5:0.5-0.7. Further, the preparation process of the modified PET comprises the following steps: Adding terephthalic acid, ethylene glycol and imidazole glycol monomers into a reaction kettle, adding a catalytic amount of ethylene glycol antimony, and carrying out esterification reaction under the protection of nitrogen, wherein the esterification temperature is 250-260 ℃ and the pressure is 0.3-0.4 MPa; After the esterification reaction is finished, adding a stabilizer triphenyl phosphite and a polycondensation catalyst antimonous oxide into a reaction kettle, synchronously vacuumizing, heating to 250-270 ℃ for reacting for 2-3 hours, and cooling and blanking to obtain the catalyst. Further, the preparation process of the modified silicon dioxide comprises the following steps: Dispersing nano silicon dioxide particles in absolute ethyl alcohol by ultrasonic, adding a silane coupling agent KH560, raising the temperature, carrying out reflux reaction for 8 hours, centrifuging after the reaction is finished, washing with absolute ethyl alcohol, drying for standby, dispersing the dried solid in absolute ethyl alcohol again, adding a compo