| In the production of lithium-ion batteries,a special pressure-sensitive adhesive tape for fixing and insulating the battery core and the termination portion of a lithium-ion battery such as a square or a cylinder is required.However,most of these products have problems in electrolyte resistance technology,so it is of great significance to develop an electrolyte-resistant lithium ion battery termination tape.This thesis uses methyl methacrylate(MMA),butyl acrylate(BA),isooctyl acrylate(2-EHA),2-hydroxyethyl acrylate(2-HEA),acrylic acid(AA)or methacrylic acid.Glycidyl ester(GMA)is a monomer,a series of acrylate pressure sensitive adhesive base glues are synthesized by solution polymerization,and the obtained acrylate pressure sensitive adhesive is compounded with a suitable tackifying resin and curing agent to obtain corresponding Modified acrylate pressure sensitive adhesive tape.First,the influence of the amount of the initiator and each monomer on the viscosity of the obtained base glue and the adhesive properties of the obtained tape(including initial tack,180 peel strength,and tackiness)were investigated by a single variable method.Based on this,the formulation of the base glue was optimized by orthogonal test and its chemical structure was characterized by infrared spectroscopy(FT-IR).Then,based on the optimal formulation base glue,two kinds of tackifying resins(rosin and hydrogenated rosin)and four curing agents(aluminium acetylacetonate(AIAl),isocyanate(M-80),and sealing were studied respectively.The effect of the amount of isocyanate(XC-327)and epoxy(GA-240)on the adhesive properties and electrolyte resistance of pressure-sensitive adhesive tape,and the use of DSC,TGA and contact angle tester The thermal properties and surface wetting properties of the sensitive gel were tested and analyzed.The results showed that the basic glue formula was: MMA8,2-EHA35,BA10,2-HEA2,AA2,BPO1.2%,supplemented by 10% hydrogenated rosin as a tackifier,and the best performance of the tape made with 0.4% GA-240,the initial tack is 4# steel ball,180° peel strength is 5.84N/25 mm,and the viscosity is 94 h.the electrolyte resistance is 1.7d,and the heat resistance is 120°C2d without residue glue,but the tape is still difficult to meet the electrolyte resistance requirement of the lithium ion battery termination tape(soaked at room temperature for 3 days).Finally,on the basis of the above basic glue formula,continue to replace the AA synthetic glue with GMA;or add an appropriate amount of fluoromonomer(trifluorooctyl methacrylate(G06B)and dodecafluoroheptyl methacrylate(DFMA)))to modify the pressure sensitive adhesive,and use FT-IR,GPC,DSC and TGA to test the chemical structure and thermal properties of the obtained glue,and at the same time,the contact tape test,electrolyte resistance test and bonding of the obtained tape Performance Testing.The results showed that:(1)GMA was used instead of AA,the electrolyte resistance of the tape was improved,and the prepared tape could be immersed in the electrolyte at room temperature for 2 days;(2)changed with 1% to 9% G06 B or DFMA.The heat-resistance and electrolyte resistance of the pressure-sensitive adhesive tape are improved,and when the amount of G06 B is 3%,the prepared tape can be immersed in the electrolyte at room temperature for 3.2 days,and the lithium ion battery termination tape can be achieved.The industry requirements,and the pressure sensitive adhesive tape modified with DFMA can not meet the electrolyte resistance requirements of the lithium ion battery termination tape,and the optimal electrolyte resistance is 2.7d. |
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