Chemical corrosion resistant polyester special film formula and preparation method thereof

Abstract

The application relates to the field of special films, in particular to a chemical corrosion-resistant polyester special film formula, which is characterized in that, according to weight parts, 92-98 parts of PET matrix resin, 2-6 parts of a multifunctional modifier, 0.2-0.4 parts of a composite antioxidant, 0.1-0.3 parts of a nucleating agent, 0.05-0.2 parts of a lubricant and 0.1-0.3 parts of an opening agent are included. The modifier contains perfluoroalkyl and phosphorus hetero-phenanthrene rigid structures, the perfluoroalkyl chain segment has lower surface energy and excellent chemical inertness, can effectively block the penetration and corrosion of corrosion media such as acid, alkali and organic solvent; the phosphorus hetero-phenanthrene structure can improve the hydrolysis resistance and degradation resistance of the polyester molecular chain. Through testing, the mechanical property retention rate of the film after treatment by a corrosive solution is better than that of a conventional BOPET film, and the application can meet the use requirements of harsh chemical-resistant scenes such as chemical protection, electronic processing and special packaging.

Description

Technical Field

[0001] This invention relates to the field of special films, specifically to a chemically resistant polyester special film formulation and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET) film, as a high-performance polymer material, has become one of the most widely produced and applied specialty films in the national economy since its industrial production. This is due to its excellent mechanical strength, good optical transparency, superior insulation properties, outstanding temperature resistance, and convenient processing and molding. According to industry statistics, the global annual production of PET film has exceeded ten million tons, with the proportion of industrial functional PET film increasing year by year. Particularly in the chemical and new energy fields, more stringent requirements are being placed on the chemical corrosion resistance and hydrolysis resistance of PET film.

[0003] However, due to inherent defects in its molecular structure, ordinary PET film exhibits poor resistance to chemical corrosion and hydrolysis, severely limiting its application under harsh corrosive conditions. Specifically, PET molecular chains are composed of numerous ester bonds, which are highly reactive. Under the influence of corrosive media such as strong acids, strong alkalis, and organic solvents, they are prone to hydrolysis, alcoholysis, and transesterification, leading to molecular chain breakage and degradation. This results in a sharp decline in the film's mechanical properties, surface swelling and whitening, embrittlement and cracking, and insulation failure. Simultaneously, the high crystallinity of PET molecular chains, while resulting in a tight molecular arrangement, allows corrosive media and water molecules to easily penetrate the film, accelerating the degradation of ester bonds and further exacerbating the deterioration of film performance.

[0004] In practical applications, the problems caused by these defects are particularly prominent. In the chemical packaging field, when ordinary PET film is used for packaging corrosive chemicals, safety hazards such as film damage and leakage will occur in a short period of time, failing to meet the needs of long-term storage and transportation. In the electronics and electrical field, the PET protective insulating film used in PCB manufacturing is prone to surface whitening and decreased insulation performance after contact with chemical reagents such as etching solutions and cleaning agents, leading to short circuits and failures of electronic components. In the field of new energy battery packaging, the PET substrate used in the aluminum-plastic packaging film of lithium batteries is susceptible to hydrolytic degradation due to electrolyte corrosion and humid environments during long-term battery use, resulting in packaging failure and safety accidents such as battery leakage and fires. In the photovoltaic backsheet field, outdoor photovoltaic modules are exposed to acid and alkaline rain and humid environments for a long time, and ordinary PET backsheets are prone to hydrolytic aging, significantly shortening their service life and increasing the maintenance costs of photovoltaic modules.

[0005] To address these issues, the industry has conducted extensive research on PET film modification. However, existing modification technologies and publicly available solutions still have many shortcomings and cannot fundamentally solve the problems of insufficient chemical corrosion resistance and hydrolysis resistance of PET films. Summary of the Invention

[0006] To address the problems existing in the prior art, the purpose of this invention is to provide a chemically resistant polyester special film formulation and its preparation method.

[0007] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a chemically resistant polyester specialty film formulation, comprising, by weight parts: 92-98 parts PET matrix resin, 2-6 parts multifunctional modifier, 0.2-0.4 parts composite antioxidant, 0.1-0.3 parts nucleating agent, 0.05-0.2 parts lubricant and 0.1-0.3 parts opening agent.

[0008] Preferably, the PET resin chips are BOPET film chips with an intrinsic viscosity of 0.65-0.68 dL / g and a melt index of 20-35 g / 10 min (260℃, 2.16 kg).

[0009] Preferably, the nucleating agent is nano-talc powder with a particle size of 200-600 nm.

[0010] Preferably, the lubricant is at least one selected from pentaerythritol stearate, erucamide, and ethylene bis-stearamide. More preferably, it is ethylene bis-stearamide.

[0011] Preferably, the opening agent is fumed silica with a particle size of 100-150 nm.

[0012] Preferably, the composite antioxidant is a mixture of antioxidant 1010 and antioxidant 168, and the mass ratio of antioxidant 1010 to antioxidant 168 is 1-3:1-3.

[0013] Preferably, the preparation method of the multifunctional modifier includes: S1. Dissolve 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) in dry propylene glycol methyl ether acetate, heat to 85-90℃ under nitrogen protection and stir to dissolve. Add the first catalyst, stir evenly, and then slowly add 3-(perfluorohexyl)-1,2-epoxypropane dropwise over a period of 2-2.5 h. After the addition is complete, maintain the reaction temperature for 4-5 h. After the reaction is completed, purify to obtain a phosphorus-containing fluorine hydroxyl intermediate. S2. Dissolve isophorone diisocyanate in dry butyl acetate, heat to 45-50℃ under nitrogen protection, add a second catalyst, and slowly add the phosphorus-containing fluorine hydroxyl intermediate to the reaction system for 1.5-2 hours. Then heat to 60-65℃ and keep the reaction at that temperature for 2.5-3 hours. Cool to 30-40℃ and add n-butanol dropwise with stirring. After the addition is complete, keep the reaction at 40-50℃ for 1-2 hours. The reaction product is then distilled under reduced pressure and dried under vacuum to obtain a multifunctional modifier.

[0014] Preferably, in S1, the mass ratio of DOPO to 3-(perfluorohexyl)-1,2-epoxypropane is 2.16:3.72-3.80.

[0015] Preferably, in S1, the first catalyst is tetrabutylammonium bromide, and the amount added is 0.5%-1% of the mass of DOPO.

[0016] More preferably, in S1, the mass ratio of DOPO to 3-(perfluorohexyl)-1,2-epoxypropane is 2.16:3.75.

[0017] Preferably, in S2, the mass ratio of the phosphorus-containing fluorohydroxy intermediate, isophorone diisocyanate, and n-butanol is 5-6:2.39-3.15:0.2-0.3.

[0018] Preferably, in S2, the second catalyst is DBTDL, and the amount added is 0.02%-0.03% of the mass of isophorone diisocyanate.

[0019] More preferably, in S2, the mass ratio of the phosphorus-containing fluorohydroxy intermediate, isophorone diisocyanate, and n-butanol is 5.5:2.77:0.25.

[0020] Secondly, the present invention provides a method for preparing a chemically resistant polyester special film, comprising: Step 1: Weigh out the PET matrix resin, multifunctional modifier, composite antioxidant, nucleating agent, lubricant, and opening agent according to the weight proportions, put them into a high-speed mixer, and stir and premix at 80-90℃ for 15-20 minutes to obtain a premix; send the premix into a dryer and dry at 140-160℃ for 4-6 hours, controlling the moisture content to ≤50ppm; Step 2: Feed the dried premixed material into a twin-screw extruder and control the temperature of each section: Zone 1 240-250℃, Zone 2 255-260℃, Zone 3 260-265℃, Zone 4 260-265℃, Zone 5 255-260℃, and the die head temperature 260-265℃; the screw speed is 300-400 rpm. After melt extrusion, the material is cast through a T-die to obtain a cast sheet with a thickness of 100-200 μm. Step 3: The cast sheet is fed into a biaxial stretching machine, first stretched longitudinally at 85-95℃ with a stretching ratio of 3.2-3.8 times, and then stretched transversely at 100-110℃ with a stretching ratio of 3.5-4.0 times. The stretched film is then sent to a heat setting oven and heat-set at 190-210℃ for 3-5 minutes. After being cooled to room temperature by cooling rollers, it is wound up to obtain a chemically resistant polyester special film with a thickness of 10-20μm.

[0021] The beneficial effects of this invention are as follows: 1. The special film prepared by this invention uses PET resin as a matrix and incorporates multifunctional modifiers and various additives. The modifiers contain rigid structures of perfluoroalkyl and phosphaphenanthrene compounds. The perfluoroalkyl segments possess low surface energy and excellent chemical inertness, effectively blocking the penetration and erosion of corrosive media such as acids, alkalis, and organic solvents. The phosphaphenanthrene structure enhances the hydrolysis and degradation resistance of the polyester molecular chain. Testing shows that the film of this invention, after treatment with corrosive solutions, retains mechanical properties better than conventional BOPET films, meeting the requirements of harsh chemical-resistant applications such as chemical protection, electronic manufacturing processes, and special packaging.

[0022] 2. The multifunctional modifier synthesized in this invention introduces a large number of urethane polar groups through the isophorone diisocyanate reaction, which can form strong hydrogen bonds with the groups of the PET matrix molecular chain, thereby taking into account both the functionality of the fluorinated segments and the compatibility with the polyester matrix, avoiding the problems of poor compatibility and easy migration and precipitation of traditional fluorinated additives.

[0023] 3. The phosphorus-phenanthrene structure in the modifier forms a synergistic antioxidant effect with the composite antioxidant, which can significantly inhibit the thermal degradation of PET resin during high-temperature melt processing and ensure the stability of the processing. The nano-talc nucleating agent in the formula can refine the PET crystal grains and improve the uniformity of crystallization. Combined with the lubricating effect of the lubricant, it can improve the fluidity of the melt processing and improve the product yield.

[0024] 4. The multifunctional modifier synthesized in this invention simultaneously introduces multiple functional elements such as phosphorus, fluorine, and nitrogen. While achieving chemical corrosion resistance, it also possesses antioxidant, flame-retardant, and weather-resistant properties. This eliminates the need for multiple additional functional additives, significantly simplifying the formulation system and reducing the risk of incompatibility or precipitation associated with multiple additive combinations. Furthermore, this invention employs a blending modification process, which, compared to copolymer modification of fluorinated polyesters, has a shorter process flow, lower raw material costs, and a higher overall cost-effectiveness, possessing strong market promotion and industrialization value. Detailed Implementation

[0025] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0026] The present invention will be further described below with reference to the following embodiments. Example 1

[0027] A chemically resistant polyester specialty film formulation, comprising, by weight parts: 95 parts PET matrix resin, 5 parts multifunctional modifier, 0.3 parts composite antioxidant, 0.2 parts nucleating agent, 0.1 parts lubricant, and 0.2 parts opening agent.

[0028] The PET matrix resin is made of BOPET film chips with an intrinsic viscosity of 0.66 dL / g and a melt index of 28 g / 10 min (260℃, 2.16 kg). The nucleating agent is nano-talc powder with a particle size of 300-500 nm. The lubricant is ethylene bis-stearamide. The opening agent is fumed silica with a particle size of 100 nm. The composite antioxidant is antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1.

[0029] The preparation method of the multifunctional modifier includes: S1. Dissolve 21.6 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) in 100 g of dry propylene glycol methyl ether acetate. Under nitrogen protection, heat to 88 °C, stir to dissolve, add 0.216 g of tetrabutylammonium bromide, stir evenly, and then slowly add 37.5 g of 3-(perfluorohexyl)-1,2-epoxypropane dropwise, controlling the dropwise addition time to 2 h, and keep the reaction at this temperature for 4.5 h. After the reaction is complete, remove the solvent by vacuum distillation, cool, add dichloromethane to dissolve, wash successively with dilute hydrochloric acid and saturated brine, collect the organic phase filtrate, and remove dichloromethane by rotary evaporation to obtain a phosphorus-fluorine-hydroxyl intermediate. S2. Dissolve 27.7g of isophorone diisocyanate in 80g of dry butyl acetate. Under nitrogen protection, heat to 48℃ and add 0.0083g of dibutyltin dilaurate. Dilute 55g of phosphorus-containing fluorine hydroxyl intermediate with 100g of butyl acetate and slowly add it dropwise to the reaction vessel over 2 hours. After the addition is complete, heat to 62℃ and maintain the temperature for 3 hours. Cool to 35℃ and slowly add 2.5g of n-butanol dropwise with stirring. After the addition is complete, maintain the temperature at 45℃ for 1.5 hours. Transfer the reaction solution to a rotary evaporator and distill under reduced pressure to remove excess methanol, butyl acetate, and any remaining low-boiling substances. Dry the obtained product in a vacuum drying oven at 60℃ for 5 hours to obtain a multifunctional modifier.

[0030] The preparation method of the above-mentioned chemically resistant polyester special film includes the following steps: Step 1: Weigh each raw material according to the above ratio, put them into a high-speed mixer, stir and premix at 85℃ for 18 minutes to obtain a premix; send the premix into a dryer and dry at 150℃ for 5 hours, controlling the moisture content to ≤30ppm.

[0031] Step 2: Feed the dried premixed material into a twin-screw extruder and control the temperature of each section: Zone 1 245℃, Zone 2 258℃, Zone 3 262℃, Zone 4 262℃, Zone 5 258℃, and the die head temperature 262℃; the screw speed is 350 rpm. After melt extrusion, the material is cast through a T-die to obtain a 150μm thick sheet.

[0032] Step 3: The cast sheet is fed into a biaxial stretching machine, first stretched longitudinally at 90°C with a stretching ratio of 3.5 times, and then stretched transversely at 105°C with a stretching ratio of 3.8 times. The stretched film is then sent to a heat setting oven and heat-set at 200°C for 4 minutes. After being cooled to room temperature by cooling rollers, it is wound up to obtain a chemically resistant polyester special film with a thickness of 12μm. Example 2

[0033] A chemically resistant polyester specialty film formulation, comprising, by weight parts: 98 parts of PET matrix resin, 2 parts of multifunctional modifier, 0.2 parts of composite antioxidant, 0.1 parts of nucleating agent, 0.05 parts of lubricant, and 0.1 parts of opening agent.

[0034] The PET matrix resin is made of BOPET film chips with an intrinsic viscosity of 0.66 dL / g and a melt index of 28 g / 10 min (260℃, 2.16 kg). The nucleating agent is nano-talc powder with a particle size of 300-500 nm. The lubricant is ethylene bis-stearamide. The opening agent is fumed silica with a particle size of 100 nm. The composite antioxidant is antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1.

[0035] The preparation method of the multifunctional modifier includes: S1: Under nitrogen protection, 21.6 g DOPO was dissolved in 100 g dry propylene glycol methyl ether acetate at 85 °C. 0.108 g tetrabutylammonium bromide (0.5% of the mass of DOPO) was added, and 37.2 g 3-(perfluorohexyl)-1,2-epoxypropane was slowly added dropwise over 2 h. The reaction was maintained at this temperature for 4 h. The phosphorus-containing fluorine hydroxyl intermediate was obtained after purification.

[0036] S2: Under nitrogen protection, 23.9g of IPDI was dissolved in 80g of dry butyl acetate, and 0.0048g of DBTDL (0.02% of the mass of IPDI) was added at 45℃. 50g of phosphorus-containing fluorohydroxy intermediate was slowly added, and the reaction was carried out at 60℃ for 2.5h after 1.5h of feeding. The temperature was then lowered to 30℃, and 2.0g of n-butanol was added dropwise. The reaction was carried out at 40℃ for 1h. The modifier was obtained by vacuum distillation and vacuum drying.

[0037] The preparation method of the above-mentioned chemically resistant polyester special film includes the following steps: Step 1: Weigh each raw material according to the above ratio, put them into a high-speed mixer, stir and premix at 80℃ for 15 minutes to obtain a premix; send the premix into a dryer and dry at 140℃ for 6 hours, controlling the moisture content to ≤45ppm.

[0038] Step 2: Feed the dried premixed material into a twin-screw extruder and control the temperature of each section: Zone 1 240℃, Zone 2 255℃, Zone 3 260℃, Zone 4 260℃, Zone 5 255℃, and the die head temperature 260℃; the screw speed is 300 rpm. After melt extrusion, the material is cast through a T-die to obtain a 100μm thick sheet.

[0039] Step 3: The cast sheet is fed into a biaxial stretching machine, first stretched longitudinally at 85°C with a stretching ratio of 3.2 times, and then stretched transversely at 100°C with a stretching ratio of 3.5 times; the stretched film is sent into a heat setting oven and heat-set at 190°C for 5 minutes; after being cooled to room temperature by cooling rollers, it is wound up to obtain a polyester film with a thickness of 10μm. Example 3

[0040] A chemically resistant polyester specialty film formulation, comprising, by weight parts: 92 parts of PET matrix resin, 6 parts of multifunctional modifier, 0.4 parts of composite antioxidant, 0.3 parts of nucleating agent, 0.2 parts of lubricant, and 0.3 parts of opening agent.

[0041] The PET matrix resin is made of BOPET film chips with an intrinsic viscosity of 0.66 dL / g and a melt index of 28 g / 10 min (260℃, 2.16 kg). The nucleating agent is nano-talc powder with a particle size of 300-500 nm. The lubricant is ethylene bis-stearamide. The opening agent is fumed silica with a particle size of 100 nm. The composite antioxidant is antioxidant 1010 and antioxidant 168 mixed in a mass ratio of 1:1.

[0042] The preparation method of the multifunctional modifier includes: S1: Under nitrogen protection, 21.6 g DOPO was dissolved in 100 g dry propylene glycol methyl ether acetate at 90 °C. 0.162 g tetrabutylammonium bromide (0.75% of the mass of DOPO) was added, and 38.0 g 3-(perfluorohexyl)-1,2-epoxypropane was slowly added dropwise over 2.5 h. The reaction was maintained at this temperature for 5 h. The intermediate containing phosphorus fluorine hydroxyl groups was obtained after purification.

[0043] S2: Under nitrogen protection, 31.5g of IPDI was dissolved in 80g of dry butyl acetate, and 0.0079g of DBTDL (0.025% of the mass of IPDI) was added at 50℃. 60g of phosphorus-containing fluorohydroxy intermediate was slowly added, and the reaction was carried out at 65℃ for 3 hours after feeding for 2 hours. The temperature was then lowered to 40℃, and 3.0g of n-butanol was added dropwise. The reaction was carried out at 50℃ for 2 hours. The modifier was obtained by vacuum distillation and vacuum drying.

[0044] The preparation method of the above-mentioned chemically resistant polyester special film includes the following steps: Step 1: Weigh each raw material according to the above ratio, put them into a high-speed mixer, stir and premix at 90℃ for 20 minutes to obtain a premix; send the premix into a dryer and dry at 160℃ for 4 hours, controlling the moisture content to ≤40ppm.

[0045] Step 2: Feed the dried premixed material into a twin-screw extruder and control the temperature of each section: Zone 1 250℃, Zone 2 260℃, Zone 3 265℃, Zone 4 265℃, Zone 5 260℃, and the die head temperature 265℃; the screw speed is 400 rpm. After melt extrusion, the material is cast through a T-die to obtain a 200μm thick sheet.

[0046] Step 3: The cast sheet is fed into a biaxial stretching machine, first stretched longitudinally at 95°C with a stretching ratio of 3.8 times, and then stretched transversely at 110°C with a stretching ratio of 4.0 times; the stretched film is sent into a heat setting oven and heat-set at 210°C for 3 minutes; after being cooled to room temperature by cooling rollers, it is wound up to obtain a polyester film with a thickness of 20μm.

[0047] Comparative Example 1 A special polyester film formulation differs from Example 1 in that it does not contain a multifunctional modifier.

[0048] The formula, calculated by weight, includes: 100 parts PET matrix resin, 0.3 parts composite antioxidant, 0.2 parts nano talc, 0.1 parts ethylene bis-stearamide, and 0.2 parts fumed silica.

[0049] The preparation method was exactly the same as in Example 1, and a 12 μm thick polyester film was obtained.

[0050] Comparative Example 2 A special polyester film formulation differs from Example 1 in that 5 parts of a monofluorinated component modifier are used to replace the multifunctional modifier in Example 1 by the same mass, while the proportions of the remaining raw materials are exactly the same as in Example 1.

[0051] The preparation methods of the monofluorinated component modifier include: S1: Dissolve 37.5g of 3-(perfluorohexyl)-1,2-epoxypropane in 100g of dry propylene glycol methyl ether acetate, heat to 88℃ under nitrogen protection, add 0.216g of tetrabutylammonium bromide, stir well, then add 10g of propylene glycol dropwise over 2h, keep the reaction at this temperature for 4.5h, and purify to obtain a fluorinated hydroxyl intermediate.

[0052] S2: Dissolve 27.7g IPDI in 80g dry butyl acetate, heat to 48℃ under nitrogen protection, add 0.0083g DBTDL, slowly add 55g of the above fluorinated hydroxyl intermediate, add over 2h, and keep the reaction at 62℃ for 3h; cool to 35℃, add 2.5g n-butanol dropwise, keep at 45℃ for 1.5h, and obtain the monofluorinated component modifier by vacuum distillation and vacuum drying.

[0053] The preparation method was exactly the same as in Example 1, and a 12 μm thick polyester film was obtained.

[0054] Comparative Example 3 A special polyester film formulation differs from Example 1 in that 5 parts of a single phosphorus component modifier are used to replace the multifunctional modifier in Example 1 by the same mass, while the proportions of the remaining raw materials are exactly the same as in Example 1.

[0055] The preparation method of the single phosphorus component modifier includes: S1: Dissolve 21.6g DOPO in 100g dry propylene glycol methyl ether acetate, heat to 88℃ under nitrogen protection and stir to dissolve, add 0.216g tetrabutylammonium bromide, stir evenly and then slowly add 10g propylene oxide dropwise over 2h, keep the reaction at the temperature for 4.5h, and purify to obtain a phosphorus-containing hydroxyl intermediate.

[0056] S2: Dissolve 27.7g IPDI in 80g dry butyl acetate, heat to 48℃ under nitrogen protection, add 0.0083g DBTDL, slowly add 55g of the above phosphorus-containing hydroxyl intermediate, add over 2h, and keep the reaction at 62℃ for 3h; cool to 35℃, add 2.5g n-butanol dropwise, keep at 45℃ for 1.5h, and obtain the single phosphorus component modifier by vacuum distillation and vacuum drying.

[0057] The preparation method was exactly the same as in Example 1, and a 12 μm thick polyester film was obtained.

[0058] Experimental testing Tensile strength (longitudinal) and elongation at break (longitudinal): Refer to GB / T 1040.3-2006, tensile speed 50 mm / min; Acid resistance (tensile strength retention rate): Refer to 10% H2SO4 aqueous solution, soak at 25℃ for 72h, test the tensile strength before and after soaking, and calculate the retention rate; Alkali resistance (tensile strength retention): Refer to a 10% NaOH aqueous solution, soak at 25℃ for 72 hours, test the tensile strength before and after soaking, and calculate the retention rate; Solvent resistance (tensile strength retention rate): The sample was immersed in analytical grade acetone at a constant temperature of 25°C for 24 hours. The tensile strength before and after immersion was tested, and the retention rate was calculated. Water contact angle: Refer to GB / T 30693-2014, horizontal drop method, 25℃; Limiting Oxygen Index (LOI): Refer to GB / T 2406.2-2009, tested at room temperature; Thermal decomposition temperature (T5%): Refer to GB / T 27761-2011, nitrogen atmosphere, heating rate 10℃ / min, record the 5% thermal weight loss temperature.

[0059] The test results are shown in Table 1: Table 1. Overall performance test results of the thin films in Example 1 and the comparative example. As shown in Table 1, the chemical corrosion resistance of Example 1 is far superior to that of the other comparative examples. The tensile strength retention rate after immersion in acids, alkalis, and organic solvents all exceeded 90%, with alkali resistance improving by 32.7% compared to Comparative Example 1. This solves the problems of pure PET film being easily hydrolyzed by alkali and having poor resistance to organic solvents. The multifunctional modifier of this invention achieves a synergistic effect of phosphorus and fluorine, while also considering hydrophobicity, flame retardancy, and thermal stability. The water contact angle of Example 1 reaches 118°, and the LOI reaches 31.2%, which are significantly improved compared to Comparative Examples 2 or 3 modified with monofluorine or monophosphorus. Furthermore, the strength data shows that the structure of the modifier in Example 1 has good compatibility with the PET matrix. The mechanical properties not only do not decrease but are actually improved compared to pure PET film, meeting the application requirements of special films.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A chemically resistant polyester special film formulation, characterized in that, Calculated by weight, including: 92-98 parts PET matrix resin, 2-6 parts multifunctional modifier, 0.2-0.4 parts composite antioxidant, 0.1-0.3 parts nucleating agent, 0.05-0.2 parts lubricant and 0.1-0.3 parts opening agent.

2. The chemically resistant polyester special film formulation according to claim 1, characterized in that, The PET resin chips are BOPET film chips with an intrinsic viscosity of 0.65-0.68 dL / g and a melt index of 20-35 g / 10 min at 260℃ and 2.16 kg.

3. The chemically resistant polyester special film formulation according to claim 1, characterized in that, The nucleating agent is nano-talc powder with a particle size of 200-600 nm.

4. The chemically resistant polyester special film formulation according to claim 1, characterized in that, The lubricant is at least one of pentaerythritol stearate, erucamide, and ethylene bis-stearamide.

5. The chemically resistant polyester special film formulation according to claim 1, characterized in that, The opening agent is fumed silica with a particle size of 100-150 nm.

6. The chemically resistant polyester special film formulation according to claim 1, characterized in that, The composite antioxidant is a mixture of antioxidant 1010 and antioxidant 168, with a mass ratio of antioxidant 1010 to antioxidant 168 of 1-3:1-3.

7. The chemically resistant polyester special film formulation according to claim 1, characterized in that, The preparation method of the multifunctional modifier includes: S1. Dissolve 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in dry propylene glycol methyl ether acetate, heat to 85-90℃ under nitrogen protection and stir to dissolve. Add the first catalyst, stir evenly, and then slowly add 3-(perfluorohexyl)-1,2-epoxypropane dropwise over a period of 2-2.5 h. After the addition is complete, maintain the reaction temperature for 4-5 h. After the reaction is completed, purify to obtain a phosphorus-containing fluorine hydroxyl intermediate. S2. Dissolve isophorone diisocyanate in dry butyl acetate, heat to 45-50℃ under nitrogen protection, add a second catalyst, and slowly add the phosphorus-containing fluorine hydroxyl intermediate to the reaction system for 1.5-2 hours. Then heat to 60-65℃ and keep the reaction at that temperature for 2.5-3 hours. Cool to 30-40℃ and add n-butanol dropwise with stirring. After the addition is complete, keep the reaction at 40-50℃ for 1-2 hours. The reaction product is then distilled under reduced pressure and dried under vacuum to obtain a multifunctional modifier.

8. The chemically resistant polyester special film formulation according to claim 1, characterized in that, In S1, the mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 3-(perfluorohexyl)-1,2-epoxypropane is 2.16:3.72-3.80; the first catalyst is tetrabutylammonium bromide, and the amount added is 0.5%-1% of the mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

9. The chemically resistant polyester special film formulation according to claim 1, characterized in that, In S2, the mass ratio of phosphorus-containing fluorine hydroxyl intermediate, isophorone diisocyanate, and n-butanol is 5-6:2.39-3.15:0.2-0.3; the second catalyst is dibutyltin dilaurate, and the amount added is 0.02%-0.03% of the mass of isophorone diisocyanate.

10. A method for preparing a film according to the chemical corrosion resistant polyester special film formulation of claim 1, comprising: Step 1: Weigh out the PET matrix resin, multifunctional modifier, composite antioxidant, nucleating agent, lubricant, and opening agent according to the weight proportions, put them into a high-speed mixer and stir to premix to obtain a premix; send the premix to a dryer to dry; Step 2: The dried premixed material is fed into a twin-screw extruder, melt-extruded, and then cast into a sheet through a T-die to obtain a cast sheet; Step 3: The cast film is fed into a biaxial stretching machine for longitudinal and transverse stretching. The stretched film is then sent to a heat-setting oven for heat setting. After being cooled to room temperature by cooling rollers, it is wound up to obtain a chemically resistant polyester special film.

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