Antistatic and high-strength BOPET film and preparation method thereof

Abstract

The invention discloses an antistatic and high-strength BOPET (Biaxially Oriented Polyethylene Terephthalate) film and a preparation method thereof, and relates to a BOPET film and a preparation method thereof. The invention aims to solve the problems of poor antistatic property and insufficient mechanical property of the existing BOPET film. The BOPET film disclosed by the invention is synthesized from the following raw materials in parts by weight: 1000 to 2000 parts of binary acid monomer, 450 to 1000 parts of dihydric alcohol monomer, 15 to 90 parts of carbon nano tube, 15 to 90 parts of ionic liquid, 0.6 to 1.2 parts of catalyst and 0.6 to 2 parts of heat stabilizer. The BOPET film is simple in preparation method, has excellent antistatic property, mechanical property and thermal stability, and can effectively prevent accumulation of polyester electrostatic charges. The invention belongs to the technical field of polyester synthesis and processing.

Description

TECHNICAL FIELD

[0001] The application relates to a BOPET film and a preparation method thereof, and belongs to the technical field of polyester synthesis and processing. BACKGROUND

[0002] The BOPET film has good mechanical properties and chemical stability, large output and low price, and is widely applied in the fields of textile fibers, films, bottled containers and automobiles, electronics and the like. However, the relatively low polar molecular structure of the BOPET film makes the film itself hydrophobic, is conducive to the accumulation of static electricity, and has a moisture absorption rate of only 0.4% under standard conditions and a surface resistivity as high as 10 13 ~10 14 Ω. According to statistics, the damage of electronic products caused by static discharge in the electronic industry is as high as 20 billion US dollars per year.

[0003] In the prior art, in order to improve the antistatic property of the BOPET film, some people add polyether in the synthesis stage through a copolymerization method, such as Chinese patent CN118599097A, but the effect achieved by this method is limited, the surface resistivity is 10 9 ~10 11 Ω; the surface coating method can also effectively improve the antistatic property of the BOPET film, such as Chinese patent CN116041770B, this method can reduce the surface resistivity of the BOPET film to 10 6 Ω, but the wear resistance is usually poor, the bonding force between the coating and the surface of the BOPET film is poor, and the service life is short.

[0004] Compared with the above-mentioned methods, the blending method is the most widely used method at present, PET chips and conductive fillers or antistatic agents are mixed into an extruder to improve the antistatic property, and the method is based on the formation of an interpenetrating continuous conductive polymer network. Carbon nanotubes are relatively common conductive fillers, which can achieve the effects of antistatic and reinforcement, but when the content is relatively high, the carbon nanotubes are not easy to disperse and are easy to agglomerate, and the flowability of the PET melt is greatly reduced, which affects the processing performance. SUMMARY

[0005] The application is proposed to solve the problems of poor antistatic property and insufficient mechanical property of the existing BOPET film, and further provides an antistatic and high-strength BOPET film and a preparation method thereof.

[0006] The technical scheme adopted by the application to solve the above-mentioned problems is that the mass fractions of the components in the antistatic and high-strength BOPET film are as follows: 1000-2000 parts of a diacid monomer, 450-1000 parts of a diol monomer, 15-90 parts of carbon nanotubes, 15-90 parts of an ionic liquid, 0.6-1.2 parts of a catalyst and 0.6-2 parts of a heat stabilizer.

[0007] Further, the diacid monomer is one of terephthalic acid and isophthalic acid.

[0008] Further, the diol monomer is one or more of ethylene glycol, polyethylene glycol, propylene glycol, and butanediol.

[0009] Further, the carbon nanotube is one or more of carboxylated carbon nanotube, hydroxylated carbon nanotube, and aminated carbon nanotube, and the average particle size of the carbon nanotube is 10-100 nm.

[0010] Further, the ionic liquid is one of 1-ethyl-3-methyl-imidazole bis-trifluoromethyl sulfonimide salt, 1-allyl-3-methyl-imidazole bis-imidazole salt, 1-ethyl-3-methyl-imidazole tetrafluoroboric acid salt, and 1-ethyl-3-methyl-imidazole bromide salt.

[0011] Further, the catalyst is one of antimony-based, titanium-based, or germanium-based catalysts.

[0012] Further, the stabilizer is one of phosphoric acid ester and phosphorous acid ester.

[0013] The preparation method of the anti-static and high-strength BOPET film includes the following steps: Step 1: uniformly mix the diacid monomer, diol monomer, carbon nanotube, ionic liquid, catalyst, and stabilizer in a reaction container, and perform esterification under nitrogen pressure; when the water output reaches more than 95% of the theoretical value, the esterification is completed; Step 2: after the esterification is completed, perform polycondensation under high vacuum until the stirrer reaches the predetermined stirring power; Step 3: after the polycondensation is completed, the nitrogen is released to normal pressure, and the material is discharged, cooled, cut, and dried, and then the BOPET film is obtained through bidirectional stretching.

[0014] Further, the nitrogen pressure in step 1 is 150 Kpa, and the heating temperature is 220-270℃; In step 2, the high vacuum is greater than or equal to -100 Kpa, the heating temperature is 270-280℃, and the predetermined stirring power is 69 W, and the intrinsic viscosity corresponding to this power is 0.68 dL / g; In step 3, the thickness of the BOPET film is 5-20 microns.

[0015] The application has the beneficial effects that: the application adds carbon nanotubes and ionic liquid in a polyester reaction kettle through a one-pot method, and the process is simple. The carbon nanotubes have extremely high mechanical strength, excellent electric and thermal conductivity, and the ionic liquid has good thermal stability and chemical stability, high electrical conductivity, antibacterial properties and the like, and can be used as an antistatic agent, a plasticizer and a dispersant. Therefore, the addition of the carbon nanotubes and the ionic liquid can improve the antistatic property, mechanical property and thermal property of PET, and also ensure the dispersibility of the carbon nanotubes and the processing property of the PET melt. Therefore, the BOPET film of the application has excellent antistatic property and mechanical property, and can meet the needs of the electronic industry, the automobile industry, the medical instrument industry and the like. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of the SEM result of Comparative Example 2; Figure 2 is a schematic diagram of the SEM result of Example 3.

[0017] Example Example 1 1500g of terephthalic acid, 675g of ethylene glycol, 22g of carbon nanotubes, 22g of 1-ethyl-3-methylimidazolium tetrafluoroborate, 0.87g of a catalyst ethylene glycol antimony, and 1.0g of a stabilizer trimethyl phosphate.

[0018] The preparation steps are as follows: (1) The terephthalic acid, the ethylene glycol, the carbon nanotubes, the 1-ethyl-3-methylimidazolium tetrafluoroborate, the catalyst and the stabilizer are uniformly mixed and added into a reaction container. Nitrogen is introduced and vacuum is drawn, and the operation is repeated three times to ensure that the air in the reaction container is completely removed. Esterification is carried out at 270℃. When the water output reaches more than 95% of the theoretical value, the esterification is completed; (2) After the esterification is completed, the polycondensation reaction is carried out under high vacuum conditions and heating to 280℃ until the stirring power of the stirrer reaches 69W.

[0019] (3) After the polycondensation reaction is completed, nitrogen is introduced to normal pressure, and the material is discharged, cooled, cut into particles and dried, and then the BOPET film is obtained through bidirectional stretching.

[0020] Example 2 1500g of terephthalic acid, 700g of ethylene glycol, 44g of amino-functionalized carbon nanotubes, 66g of 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 0.88g of a catalyst ethylene glycol antimony, and 1.2g of a stabilizer trimethyl phosphate.

[0021] The preparation steps are as follows: (1) terephthalic acid, ethylene glycol, hydroxylated carbon nanotubes, 1-allyl-3-methyl imidazole bis (trifluoromethane sulfonate) salt, catalyst, stabilizer are mixed uniformly and added into the reaction container. Nitrogen is introduced and vacuum is applied, and the operation is repeated three times to ensure that the air in the reaction container is completely removed. Esterification is carried out at 270°C. When the water output reaches more than 95% of the theoretical value, the esterification reaction is completed; (2) After the esterification reaction is completed, the polycondensation reaction is carried out under high vacuum conditions by heating to 280°C until the stirring power of the stirrer reaches 69W.

[0022] (3) After the polycondensation reaction is completed, nitrogen is introduced to normal pressure, and the material is discharged, cooled, cut, and dried, and then the BOPET film is obtained by bidirectional stretching.

[0023] Example 3 1500g terephthalic acid, ethylene glycol 800g, carboxylated carbon nanotubes 69g, 1-allyl-3-methyl imidazole bis (trifluoromethane sulfonate) salt 115g, catalyst ethylene glycol antimony 1.0g, stabilizer trimethyl phosphate 1.2g.

[0024] The preparation steps are as follows: (1) terephthalic acid, ethylene glycol, carboxylated carbon nanotubes, 1-allyl-3-methyl imidazole bis (trifluoromethane sulfonate) salt, catalyst, stabilizer are mixed uniformly and added into the reaction container. Nitrogen is introduced and vacuum is applied, and the operation is repeated three times to ensure that the air in the reaction container is completely removed. Esterification is carried out at 270°C. When the water output reaches more than 95% of the theoretical value, the esterification reaction is completed; (2) After the esterification reaction is completed, the polycondensation reaction is carried out under high vacuum conditions by heating to 280°C until the stirring power of the stirrer reaches 69W.

[0025] (3) After the polycondensation reaction is completed, nitrogen is introduced to normal pressure, and the material is discharged, cooled, cut, and dried, and then the BOPET film is obtained by bidirectional stretching.

[0026] Example 4 1500g terephthalic acid, ethylene glycol 900g, hydroxylated carbon nanotubes 72g, 1-allyl-3-methyl imidazole bromide salt 168g, catalyst ethylene glycol antimony 1.0g, stabilizer trimethyl phosphate 1.2g.

[0027] The preparation steps are as follows: (1) terephthalic acid, ethylene glycol, hydroxylated carbon nanotubes, 1-ethyl-3-methyl imidazole bromide, catalyst, stabilizer were mixed uniformly and added into a reaction container. Nitrogen was introduced and vacuum was applied, and the operation was repeated three times to ensure that the air in the reaction container was completely removed. Esterification was carried out at 270°C. When the water output reached more than 95% of the theoretical value, the esterification reaction was completed. (2) After the esterification reaction was completed, the temperature was raised to 280°C under high vacuum conditions to carry out the polycondensation reaction until the stirring power of the stirrer reached 69W.

[0028] (3) After the polycondensation reaction was completed, nitrogen was introduced to normal pressure, and the product was discharged, cooled, cut into particles, and dried. Then the BOPET film was obtained by biaxial stretching.

[0029] Comparative Example 1 1500g terephthalic acid, 675g ethylene glycol, 0.87g catalyst ethylene glycol antimony, 1.0g stabilizer trimethyl phosphate.

[0030] The preparation steps were as follows: (1) terephthalic acid, ethylene glycol, catalyst, stabilizer were mixed uniformly and added into a reaction container. Nitrogen was introduced and vacuum was applied, and the operation was repeated three times to ensure that the air in the reaction container was completely removed. Esterification was carried out at 270°C. When the water output reached more than 95% of the theoretical value, the esterification reaction was completed. (2) After the esterification reaction was completed, the temperature was raised to 280°C under high vacuum conditions to carry out the polycondensation reaction until the stirring power of the stirrer reached 69W.

[0031] (3) After the polycondensation reaction was completed, nitrogen was introduced to normal pressure, and the product was discharged, cooled, cut into particles, and dried. Then the BOPET film was obtained by biaxial stretching.

[0032] Comparative Example 2 1500g terephthalic acid, 675g ethylene glycol, 65g carbon nanotubes, 0.87g catalyst ethylene glycol antimony, 1.0g stabilizer trimethyl phosphate.

[0033] The preparation steps were as follows: (1) terephthalic acid, ethylene glycol, carbon nanotubes, catalyst, stabilizer were mixed uniformly and added into a reaction container. Nitrogen was introduced and vacuum was applied, and the operation was repeated three times to ensure that the air in the reaction container was completely removed. Esterification was carried out at 270°C. When the water output reached more than 95% of the theoretical value, the esterification reaction was completed. (2) After the esterification reaction was completed, the temperature was raised to 280°C under high vacuum conditions to carry out the polycondensation reaction until the stirring power of the stirrer reached 69W.

[0034] (3) After the polycondensation reaction is completed, nitrogen is passed to normal pressure, the material is discharged, cooled, cut into particles, dried, and then the BOPET film is obtained through bidirectional stretching.

[0035] Comparative Example 3 1500 g of terephthalic acid, 675 g of ethylene glycol, 108 g of 1-ethyl-3-methyl-imidazole bistrifluoromethanesulfonimide salt, 0.87 g of catalyst ethylene glycol antimony, and 1.0 g of stabilizer trimethyl phosphate.

[0036] The preparation steps are as follows: (1) The terephthalic acid, ethylene glycol, 1-ethyl-3-methyl-imidazole bistrifluoromethanesulfonimide salt, catalyst, and stabilizer are uniformly mixed and added to a reaction container. Nitrogen is passed and vacuum is applied, and the operation is repeated three times to ensure that the air in the reaction container is completely removed. Esterification is carried out at 270°C. When the water output reaches more than 95% of the theoretical value, the esterification reaction is completed; (2) After the esterification reaction is completed, the polycondensation reaction is carried out under high vacuum conditions and heated to 280°C until the stirring power of the stirrer reaches 69 W.

[0037] (3) After the polycondensation reaction is completed, nitrogen is passed to normal pressure, the material is discharged, cooled, cut into particles, dried, and then the BOPET film is obtained through bidirectional stretching.

[0038] Performance test The properties of the antistatic and high-strength engineering plastics provided in Examples 1-4 and Comparative Examples 1-3 above are characterized, and the specific test items, test methods are as follows, and the results are shown in Table 1.

[0039] Surface resistivity: The PET resins of the examples and comparative examples are dried, and a flat plate vulcanizing agent is used to press the film. According to the GB / T31838.3-2019 standard test, the sample size is 12 cm x 12 cm x 1 mm.

[0040] Melt index: The melt index of the copolyester is determined according to the national standard GB / T2683-2000, and the nominal load used is 2.16 kg, the test temperature is 250°C, and the test time is 5s.

[0041] Tensile property test: The sample preparation is carried out according to the GB13022-91 standard. The sample thickness is 2 mm, the narrow part width is 5 mm, and the tensile rate is 5 mm / min.

[0042] Table 1. Performance test results of PET resins of examples and comparative examples

[0043] From the data of the examples and the comparative examples, it can be seen that the carbon nanotubes and the ionic liquid can effectively improve the antistatic property of the PET. However, the antistatic property is limited when only one kind of conductive filler is added, and the surface resistivity can be reduced to the order of 10 6 .

[0044] From the results of the melt index of the comparative example 1 and the comparative example 2, it can be seen that the introduction of the carbon nanotubes limits the movement and transfer of the PET molecular chain, and affects the flowability and processability of the PET. After the introduction of the ionic liquid, the flowability of the PET melt can be greatly improved as a plasticizer.

[0045] From the results of the tensile strength of the example 3, the comparative example 1 and the comparative example 2, it can be seen that the tensile strength is increased by 17.81% when only the carbon nanotubes are added. The tensile strength is increased by 139.93% when the ionic liquid and the carbon nanotubes are added at the same time. This is because the reinforcing effect of the carbon nanotubes and the dispersion effect of the ionic liquid jointly affect, Figure 1 and Figure 2 can be effectively verified. Figure 1 The SEM results of the comparative example 2 are as follows: Figure 2 The SEM results of the example 3 are as follows:

[0046] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the technical solution of the present application, and the equivalent embodiments with equivalent changes are obtained. Any simple modification, equivalent replacement and improvement of the above examples, which does not depart from the technical solution of the present application, and is within the spirit and principle of the present application, is still within the protection scope of the technical solution of the present application.

Claims

1. An antistatic, high-strength BOPET film, characterized in that, The mass fractions of each component in the antistatic, high-strength BOPET film are as follows: 1000-2000 parts of dicarboxylic acid monomer, 450-1000 parts of diol monomer, 15-90 parts of carbon nanotubes, 15-90 parts of ionic liquid, 0.6-1.2 parts of catalyst, and 0.6-2 parts of heat stabilizer.

2. The antistatic, high-strength BOPET film according to claim 1, characterized in that, Dicarboxylic acid monomers are one of phthalic acid and isophthalic acid.

3. The antistatic, high-strength BOPET film according to claim 1, characterized in that, The diol monomer is one or more of ethylene glycol, polyethylene glycol, propylene glycol, and butanediol.

4. The antistatic, high-strength BOPET film according to claim 1, characterized in that, The carbon nanotubes are one or more of carboxylated carbon nanotubes, hydroxylated carbon nanotubes, and aminated carbon nanotubes, with an average particle size of 10-100 nm.

5. The antistatic, high-strength BOPET film according to claim 1, characterized in that, The ionic liquids are 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide, 1-allyl-3-methylimidazolium bis(imidazolium), 1-ethyl-3-methylimidazolium tetrafluoroborate and 1-ethyl-3-methylimidazolium bromide.

6. The antistatic, high-strength BOPET film according to claim 1, characterized in that, The catalyst is one of the antimony-based, titanium-based, or germanium-based catalysts.

7. The antistatic, high-strength BOPET film according to claim 1, characterized in that, Stabilizers are a type of phosphate ester or phosphite ester.

8. A method for preparing an antistatic, high-strength BOPET film, characterized in that, The steps of the method for preparing an antistatic, high-strength BOPET film include: Step 1: Mix the dicarboxylic acid monomer, diol monomer, carbon nanotubes, ionic liquid, catalyst, and stabilizer evenly and add them to the reaction vessel. Heat under nitrogen pressure to carry out the esterification reaction. When the amount of water produced reaches more than 95% of the theoretical value, the esterification reaction ends. Step 2: After the esterification reaction is completed, the polycondensation reaction is carried out under high vacuum conditions until the stirrer reaches the predetermined stirring power. Step 3: After the polycondensation reaction is completed, nitrogen gas is introduced to atmospheric pressure, the material is discharged, cooled, pelletized, and dried, and then biaxially stretched to obtain the BOPET film.

9. The method for preparing an antistatic, high-strength BOPET film according to claim 8, characterized in that, In step 1, the nitrogen pressure is 150 kPa and the heating temperature is 220-270 °C. In step 2, the high vacuum should be ≥-100Kpa, the heating temperature should be 270-280℃, the predetermined stirring power should be 69W, and the intrinsic viscosity corresponding to this power is 0.68dL / g; In step 3, the thickness of the BOPET film is 5-20 micrometers.

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