Modified polyester, method for producing the same, modified polyester composite film, and use thereof

Abstract

This invention relates to polyester materials and discloses a modified polyester containing structural unit A of formula (I), structural unit B of formula (II), structural unit C of formula (III), and silica nanoparticles; wherein R1 and R2 are each independently C1-C6 alkylene groups, X and Y are each independently F or Cl, n is a natural number between 1 and 4, m is a natural number between 1 and 5, and a is a natural number between 15 and 45. Furthermore, this invention also provides a modified polyester composite film containing the above-mentioned modified polyester, its preparation method, and its application. This modified polyester has good waterproof and breathable properties, and the preparation process is relatively environmentally friendly. Formulas (I), (II), and (III).

Description

Technical Field

[0001] This invention relates to polyester materials, specifically to a modified polyester. Furthermore, this invention also discloses a modified polyester composite film containing the aforementioned modified polyester, a method for preparing the modified polyester, and its applications. Background Technology

[0002] TPEE elastomers combine the excellent elasticity of rubber with the easy processability of thermoplastics, offering adjustable hardness and outstanding mechanical strength, excellent resilience, and a wide operating temperature range. They are widely used in automotive parts, cables and wires, and electronic appliances. With rising living standards, waterproof and moisture-absorbing materials, also known as "breathable materials," have gained significant attention. TPEE contains carboxyl and hydroxyl groups, which introduce hydrophilic groups, enabling its moisture-absorbing properties; however, its waterproof performance still needs further improvement.

[0003] CN108263051A discloses a waterproof and breathable membrane, which mainly uses a special machine tool to punch holes in the membrane substrate to form vent holes with a diameter of 0.001-0.003μm. The vent holes are used for waterproofing and breathability. The disadvantage of this method is that the vent holes are artificially created by physical processing methods, and the uniformity of the pore size cannot be guaranteed, which will result in a large difference in the breathability of the membrane.

[0004] CN103963393A discloses a waterproof and breathable composite membrane and its preparation method, using TPEE as the hydrophilic base membrane. The hydrophobic membrane is formed by electrospinning on the surface of the hydrophilic membrane. The hydrophobic membrane is composed of polyvinylidene fluoride and acrylate rubber accounting for 2.4%-9.6% of the mass of polyvinylidene fluoride, or polytetrafluoroethylene and acrylate rubber accounting for 2.4%-9.6% of the mass of polytetrafluoroethylene. This method involves a complex processing procedure, and the solutions used in the electrospinning process are toxic and harmful, which does not conform to the concept of green environmental protection. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of insufficient waterproof performance, unstable breathability, and environmental unfriendliness of existing elastomeric materials, and to provide a modified polyester, its preparation method, a modified polyester composite film, and its application. This modified polyester has good waterproof and breathable properties, and the preparation process is relatively environmentally friendly.

[0006] To achieve the above objectives, the present invention provides a modified polyester containing structural unit A of formula (I), structural unit B of formula (II), structural unit C of formula (III), and silica nanoparticles. Formula (I), Equation (II), Formula (III) Wherein, R1 and R2 are each independently C1-C6 alkylene groups, X and Y are each independently F or Cl, n is a natural number between 1 and 4, m is a natural number between 1 and 5, and a is a natural number between 15 and 45.

[0007] A second aspect of the present invention provides a method for preparing a modified polyester, comprising the following steps: S1. Under esterification conditions, a diacid monomer, a diol monomer, a modified monomer and a catalyst are reacted to obtain a prepolymer. S2. Under polymerization conditions, the prepolymer, the condensate containing the structural unit shown in formula (III), and the silica nanoparticles are brought into contact and reacted. The modified monomer contains a dicarboxylic acid having the structure shown in formula (VIII) and a monocarboxylic acid having the structure shown in formula (II); Formula (VIII) Equation (II), Formula (III) Wherein, R2 is a C1-C6 alkylene group, X and Y are each independently F or Cl, n is a natural number between 1 and 4, m is a natural number between 1 and 5, a is a natural number between 15 and 45, and the diol monomer is a C1-C6 diol.

[0008] A third aspect of the present invention provides a modified polyester composite film comprising a first film layer and a second film layer bonded together, wherein the first film layer contains the modified polyester described above or a modified polyester prepared by the above preparation method, and the second film layer contains a copolyester having structural unit D as shown in formula (IV) and structural unit E as shown in formula (V). Formula (IV), Formula (V), Among them, R A It is a C1-C4 methylene group.

[0009] The fourth aspect of the present invention provides the application of the above-described modified polyester, the modified polyester prepared by the preparation method, or the modified polyester composite film containing the above-described modified polyester in swimwear, protective clothing, waterproof jackets, life jackets, and sleeping bags.

[0010] Through the above technical solution, the modified polyester provided by the present invention simultaneously contains structural unit A shown in formula (I), structural unit B shown in formula (II), structural unit C shown in formula (III), and silica nanoparticles. Through the interaction between structural unit A shown in formula (I), structural unit B shown in formula (II), structural unit C shown in formula (III), and silica nanoparticles, the waterproof performance and breathability of the modified polyester can be effectively improved. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of the modified polyester composite film provided by the present invention.

[0012] 1. First film layer; 2. Second film layer. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] As previously stated, the first aspect of the present invention provides a modified polyester containing structural unit A of formula (I), structural unit B of formula (II), structural unit C of formula (III), and silica nanoparticles. Formula (I), Equation (II), Formula (III) In this system, R1 and R2 are each independently C1-C6 alkylene groups, X and Y are each independently F (fluorine) or Cl (chlorine), n is a natural number between 1 and 4, m is a natural number between 1 and 5, and a is a natural number between 15 and 45.

[0015] During their research, the inventors discovered that the interaction between structural unit A (as shown in Formula (I), structural unit B (as shown in Formula (II), structural unit C (as shown in Formula (III)) and silica nanoparticles gives the polyester good hydrophobic properties, thereby effectively improving the waterproof performance of the modified polyester. Furthermore, the interaction between these structural units also enables the formation of a microporous structure within the modified polyester, effectively improving its breathability. The modified polyester provided by this invention possesses high waterproof and breathable properties, making it suitable for applications in swimwear, protective clothing, waterproof jackets, life jackets, and sleeping bags.

[0016] According to the present invention, the C1-C6 alkylene groups can be -CH2-, -CH2CH2-, -CH(CH3)-, -CH2CH2CH2-, -CH2CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -(CH2)4-, -CH2CH2CH(CH3)-, -(CH3)CHCH(CH3)-, -CH2C(CH3)2-, -CH2CH(CH2CH3)-, -(CH3)C(CH2CH3)-, -CH(CH2CH2CH3)-, -(CH2)5-, -CH2CH2CH2CH(CH3)-, -(CH2)6-, or -CH2CH2CH2CH2CH(CH3)-.

[0017] Preferably, R1 and R2 are each independently C2-C5 alkylene groups, and X and Y are F. Studies have found that the modified polyester with the above-mentioned limitations has better waterproof and breathable properties. Further preferably, considering the ability to further improve the waterproof and breathable properties of the modified polyester, R1 and R2 are each independently C3-C4 alkylene groups, n=2, m=1, and a is a natural number between 25 and 35.

[0018] Preferably, in the modified polyester, the total content of structural unit A and structural unit B, calculated as halogen, is 44-305 ppm, the content of silica nanoparticles, calculated as silicon, is 128-365 ppm, and the content of structural unit C is 24-30 wt%. Controlling the content of the above structural units and silica nanoparticles within the aforementioned ranges can further enhance the interaction between the structural units and silica nanoparticles, thereby further improving the waterproof and breathable properties of the modified polyester. Further preferably, considering the ability to further improve the waterproof and breathable properties of the modified polyester, the total content of structural unit A and structural unit B, calculated as halogen, is 55-245 ppm in the modified polyester.

[0019] Preferably, the ratio of the total mass of structural unit A and structural unit B (calculated as halogen) to the mass of the silica nanoparticles (calculated as silicon) is 0.2-1.1:1, and can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, or any value between these ratios. Studies have found that the modified polyester under the above conditions has high waterproof and breathable properties. Further preferably, to further improve the waterproof and breathable properties of the modified polyester, the ratio of the total mass of structural unit A and structural unit B (calculated as halogen) to the mass of the silica nanoparticles (calculated as silicon) is 0.4-0.7:1.

[0020] Preferably, the mass ratio of structural unit A to structural unit B, calculated by halogen content, is 0.68-1.2:1, and can be 0.68:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, or any value between these values. Studies have found that the modified polyester under the above conditions exhibits high waterproof and breathable properties. Further preferably, considering the potential to further improve the waterproof and breathable properties of the modified polyester, the mass ratio of structural unit A to structural unit B, calculated by halogen content, is 0.85-1:1.

[0021] Preferably, the silica nanoparticles have a particle size of 50-100 nm. Controlling the particle size of the silica nanoparticles within this range can further improve the waterproof and breathable properties of the modified polyester. Further preferably, considering the ability to further improve the waterproof and breathable properties of the modified polyester, the silica nanoparticles are hollow silica nanoparticles.

[0022] Preferably, the modified polyester further comprises structural unit H as shown in formula (IX) and structural unit I as shown in formula (X); Formula (IV), Formula (V), Among them, R I It is a C1-C4 methyl group, where P is a natural number between 0 and 4, and R... II It is a C2-C6 alkylene group. In the above system, structural unit A shown in formula (I), structural unit B shown in formula (II), structural unit C shown in formula (III), and silica nanoparticles have better interaction effects, which can further improve the waterproof and breathable properties of the modified polyester.

[0023] A second aspect of the present invention provides a method for preparing a modified polyester, comprising the following steps: S1. Under esterification conditions, a diacid monomer, a diol monomer, a modified monomer and a catalyst are reacted to obtain a prepolymer. S2. Under polymerization conditions, the prepolymer, the condensate containing the structural unit shown in formula (III), and the silica nanoparticles are brought into contact and reacted. The modified monomer contains a dicarboxylic acid having the structure shown in formula (VIII) and a monocarboxylic acid having the structure shown in formula (II); Formula (VIII) Equation (II), Formula (III) Wherein, R2 is a C1-C6 alkylene group, X and Y are each independently F or Cl, n is a natural number between 1 and 4, m is a natural number between 1 and 5, a is a natural number between 15 and 45, and the diol monomer is a C1-C6 diol.

[0024] Studies have found that the modified polyester prepared by the above method has good waterproof and breathable properties, and does not cause pollution during the preparation process.

[0025] Preferably, R2 is a C2-C5 alkylene group, X and Y are F, and the diol monomer is a C2-C5 diol. Studies have found that the modified polyester with the above limitations has better waterproof and breathable properties. Further preferably, considering the ability to further improve the waterproof and breathable properties of the modified polyester, R2 is independently a C3-C4 alkylene group, n=2, m=1, a is a natural number between 25 and 35, and the diol monomer is a C3-C4 diol.

[0026] Preferably, based on the theoretical yield of the modified polyester, the total amount of the diacid having the structure shown in formula (VIII) and the monocarboxylic acid having the structure shown in formula (II), calculated as halogen, is 44-305 ppm; the amount of the silica nanoparticles, calculated as silicon, is 128-365 ppm; and the amount of the condensation polymer containing the structural unit shown in formula (III) is 24-30 wt%. Controlling the amounts of the above structural units and silica nanoparticles within the above range can further enhance the interaction effect between each structural unit and the silica nanoparticles, thereby further improving the waterproof and breathable properties of the modified polyester. Further preferably, based on the theoretical yield of the modified polyester, the total amount of the diacid having the structure shown in formula (VIII) and the monocarboxylic acid having the structure shown in formula (II), calculated as halogen, is 55-245 ppm.

[0027] Preferably, the ratio of the total amount of the diacid having the structure shown in formula (VIII) and the monocarboxylic acid having the structure shown in formula (II) based on halogen content to the amount of the silica nanoparticles based on silicon content is 0.2-1.1:1. Studies have found that the modified polyester under the above conditions has high waterproof and breathable properties. Further preferably, to further improve the waterproof and breathable properties of the modified polyester, the ratio of the total amount of the diacid having the structure shown in formula (VIII) and the monocarboxylic acid having the structure shown in formula (II) based on halogen content to the amount of the silica nanoparticles based on silicon content is 0.4-0.7:1.

[0028] Preferably, the ratio of the diacid having the structure shown in formula (VIII) to the monocarboxylic acid having the structure shown in formula (II), based on halogen content, is 0.68-1.2:1. Studies have found that the modified polyester under the above conditions has high waterproof and breathable properties. Further preferably, to further improve the waterproof and breathable properties of the modified polyester, the ratio of the diacid having the structure shown in formula (VIII) to the monocarboxylic acid having the structure shown in formula (II), based on halogen content, is 0.85-1:1.

[0029] Preferably, the silica nanoparticles have a particle size of 50-100 nm. Controlling the particle size of the silica nanoparticles within this range can further improve the waterproof and breathable properties of the modified polyester. Further preferably, considering the ability to further improve the waterproof and breathable properties of the modified polyester, the silica nanoparticles are hollow silica nanoparticles.

[0030] Preferably, the dicarboxylic acid monomer is a dicarboxylic acid containing the structure shown in formula (IV), and the diol monomer is a diol containing the structure shown in formula (V); Formula (IV), Formula (V), Among them, R I It is a C1-C4 methyl group, where P is a natural number between 0 and 4, and R... II It is a C2-C6 alkylene group. The diacids and diols with the above structure have better interaction effects with the modified monomers, condensation polymers containing the structural unit shown in formula (III), and silica nanoparticles, which can further improve the waterproof and breathable properties of the modified polyester.

[0031] Preferably, the molar ratio of the diacid to the diol is 1:1.2-1.4, and the amount of catalyst used is 0.5-2g relative to 1000g of diacid monomer. Under the above conditions, there is a better reaction effect between the diacid, diol, and modified monomer, which can further improve the waterproof and breathable properties of the subsequently obtained modified polyester.

[0032] Preferably, the esterification conditions at least satisfy the following: temperature 190-240℃; the polymerization conditions at least satisfy the following: temperature 250-260℃, pressure less than or equal to 100 Pa. Under the above conditions, there is a better reaction effect between the diacid, diol, and modified monomer, as well as between the prepolymer and the condensation polymer containing the structural unit shown in formula (III), and silica nanoparticles, thereby further improving the waterproof and breathable properties of the obtained modified polyester.

[0033] A third aspect of the present invention provides a modified polyester composite film, see [link to relevant documentation]. Figure 1 It includes a first film layer 1 and a second film layer 2 bonded together, wherein the first film layer 1 contains the modified polyester described above or the modified polyester prepared by the above preparation method, and the second film layer 2 contains a copolyester having structural unit D shown in formula (IV) and structural unit E shown in formula (V). Formula (IV), Formula (V), Among them, R A It is a C1-C4 methylene group.

[0034] Studies have found that the modified polyester composite film has both high waterproof and breathable properties, as well as good moisture absorption properties.

[0035] Preferably, in the second membrane layer 1, the content of structural unit E is 20-25 wt%, which can be 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, or any value between these values; the content of structural unit D is 0.5-1.3 wt%, which can be 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, or any value between these values. Controlling the content of structural unit D and structural unit E within the above range can further improve the air permeability and moisture absorption performance of the composite membrane. Further preferably, considering the ability to further improve the air permeability and moisture absorption performance of the composite membrane, in the second membrane layer 2, the content of structural unit D is 0.56-1.1 wt%.

[0036] Preferably, in the second membrane layer 2, the mass ratio of structural unit D to structural unit E is 1:20-40, and can be 1:20, 1:25, 1:30, 1:35, 1:40, or any value between these values. Controlling the mass ratio of structural unit D to structural unit E within the above range can further improve the air permeability and moisture absorption performance of the composite membrane. Further preferably, considering the ability to further improve the air permeability and moisture absorption performance of the composite membrane, the mass ratio of structural unit D to structural unit E is 1:22-35.

[0037] Preferably, the second film layer 2 further contains structural unit F shown in formula (VI) and structural unit G shown in formula (VII); Formula (IV), Formula (V), Among them, R B It is a C1-C4 methyl group, Q is a natural number between 0 and 4, and R C It is a C2-C6 alkylene group. The above structural units have better interaction effects with structural units D and E, which can further improve the air permeability and moisture absorption properties of the composite membrane.

[0038] Preferably, the thickness of the first membrane layer 1 is 10-25 μm, and the thickness of the second membrane layer 2 is 80-200 μm. Controlling the thicknesses of the first membrane layer 1 and the second membrane layer 2 within the above ranges better balances the waterproof, moisture-absorbing, and breathable properties of the composite membrane. Further preferably, considering the potential to improve the waterproof, moisture-absorbing, and breathable properties of the composite membrane, the thickness of the first membrane layer 1 is 13-23 μm, more preferably 15-20 μm; and the thickness of the second membrane layer 2 is 90-150 μm, more preferably 90-135 μm. More preferably, the thickness ratio of the first membrane layer 1 to the second membrane layer 2 is 1:4-8, and even more preferably 1:5-7.5.

[0039] The method for preparing the modified polyester composite film provided above includes: performing blown film processing on the modified polyester provided in the first aspect and a copolyester containing structural unit D shown in formula (IV) and structural unit E shown in formula (V).

[0040] Preferably, the blown film processing is performed in a double-layer blown film machine.

[0041] In actual operation, the film needs to be stirred before blown film processing. During stirring, the screw temperature of the blown film machine is set above the melting point of the respective polyester. After blown film processing, the film is drawn and collected to obtain the modified polyester composite film mentioned above.

[0042] The fourth aspect of the present invention provides the application of the modified polyester, the modified polyester composite film, or the modified polyester prepared by the above-mentioned method in swimwear, protective clothing, waterproof jackets, life jackets, and sleeping bags.

[0043] The present invention will be described in detail below through examples. In the following examples, the intrinsic viscosity parameter was measured using an automatic viscometer (Y201 type, Viscotek, USA). The melting point parameter was measured using a differential scanning calorimeter (DSC-7 type, Perkin-Elmer, USA). The terminal carboxyl group was measured using an automatic potentiometric titrator (using a phenol-chloroform mixed solvent with a volume ratio of 2:3). The contact angle was measured according to GB / T30693-2014 using an automatic contact angle measuring instrument (TY-SDJ03, Kunshan Beidou). The water vapor transmission rate was measured according to GB / T1037 using a gravimetric water vapor transmission rate tester (W309W, Shandong Saicheng Instruments). The moisture absorption rate was tested as follows: a 0.5g sample was placed in a wide-mouth bottle containing 10mL of distilled water, kept at 37℃ for 100h, and then the sample was removed. The water on the sample surface was absorbed with filter paper, and the moisture absorption rate of the sample was calculated based on the difference in mass before and after the test.

[0044] Hollow nano-silica particles were purchased from Jinan Delan Chemical Co., Ltd., with a particle size of 80 nm; nano-silica particles were purchased from Beijing Beiqing Lianke Nanoplastics Co., Ltd., with a particle size of 50 nm; PTMEG was purchased from Xinjiang Lanshan Tunhe Co., Ltd., with a number average molecular weight of 1800; PEG was purchased from Jiangsu Haian Chemical Co., Ltd., with a number average molecular weight of 1000; SIPM was purchased from Shandong Jinsheng New Materials Co., Ltd.

[0045] Example 1 (1) In a 20-liter polymerization reactor, 4000g of terephthalic acid, 4200g of 1,4-butanediol, 2g of 2,5-difluoroterephthalic acid (CAS No.: 655-14-1), 2g of 3-fluorobenzoic acid (CAS No.: 455-38-9), 1g of 4-fluorobenzoic acid (CAS No.: 456-22-4) and 5g of tetrabutyl titanate were added to the system. Nitrogen was used for purging, and the temperature was raised to 210℃. Esterification reaction was carried out at normal pressure. When the amount of water produced by esterification reached the theoretical value, 2000g of PTMEG, 20g of antioxidant 1010 and 4g of hollow silica nanoparticles were added. Then the vacuum system was turned on to reduce the pressure to below 100Pa. At the same time, the temperature inside the reactor was raised to 255℃. Waterproof modified polyester was obtained after the reaction.

[0046] In a 20-liter polymerization reactor, 4000g of terephthalic acid, 4000g of 1,4-butanediol, and 5g of tetrabutyl titanate were added to the system. The system was then purged with nitrogen and heated to 210°C. The esterification reaction was carried out at atmospheric pressure. When the amount of water produced by esterification reached the theoretical value, 1600g of PEG, 18g of antioxidant 1010, and 50g of SIPM were added. The vacuum system was then turned on to reduce the pressure to below 100Pa, while the temperature inside the reactor was raised to 255°C. After the reaction, a hygroscopic modified polyester was obtained.

[0047] (2) Waterproof modified polyester and moisture-absorbing modified polyester are injected into a double-layer blown film machine at a mass ratio of 1:5. The temperature of the first zone of the waterproof modified polyester mixing zone is set to 200℃, the temperature of the second zone is 205℃, the temperature of the third zone is 205℃, the temperature of the film outlet is 205℃, the screw speed is 100r / min, the ring blower is turned on, and the traction roller speed is 15m / min. The temperature of the first zone of the moisture-absorbing modified polyester mixing zone is set to 230℃, the temperature of the second zone is 235℃, the temperature of the third zone is 240℃, the temperature of the film outlet is 240℃, the screw speed is 100r / min, and the film is stirred. The ring blower is turned on and the traction roller speed is 3m / min. After winding, a composite film is obtained.

[0048] Example 2 (1) In a 20-liter polymerization reactor, 4000g of terephthalic acid, 4500g of 1,4-butanediol, 5g of 2,5-difluoroterephthalic acid, 5g of 3-fluorobenzoic acid, 2g of 4-fluorobenzoic acid and 8g of tetrabutyl titanate were added to the system. Nitrogen was used for purging, and the temperature was raised to 240°C. Esterification reaction was carried out at atmospheric pressure. When the amount of water produced by esterification reached the theoretical value, 2200g of PTMEG, 25g of antioxidant 168 and 6g of hollow silica nanoparticles were added. Then the vacuum system was turned on to reduce the pressure to below 100Pa. At the same time, the temperature inside the reactor was raised to 260°C. Waterproof modified polyester was obtained after the reaction.

[0049] In a 20-liter polymerization reactor, 4000g of terephthalic acid, 4000g of 1,4-butanediol, and 8g of tetrabutyl titanate were added to the system. After nitrogen purging, the temperature was raised to 240℃ and the esterification reaction was carried out at atmospheric pressure. When the amount of water produced by esterification reached the theoretical value, 1800g of PEG, 20g of antioxidant 1010, and 80g of SIPM were added. Then, the vacuum system was turned on to reduce the pressure to below 100Pa, while the temperature inside the reactor was raised to 260℃. After the reaction, a hygroscopic modified polyester was obtained.

[0050] (2) Waterproof modified polyester and moisture-absorbing modified polyester are injected into a double-layer blown film machine at a mass ratio of 1:7.5. The temperature of the first zone of the waterproof modified polyester mixing zone is set to 200℃, the temperature of the second zone is 205℃, the temperature of the third zone is 205℃, the temperature of the film outlet is 205℃, the screw speed is 100r / min, the ring blower is turned on, and the traction roller speed is 15m / min. The temperature of the first zone of the moisture-absorbing modified polyester mixing zone is set to 230℃, the temperature of the second zone is 235℃, the temperature of the third zone is 240℃, the temperature of the film outlet is 240℃, the screw speed is 100r / min, the ring blower is turned on, and the traction roller speed is 2m / min. After winding, a composite film is obtained.

[0051] Example 3 (1) In a 20-liter polymerization reactor, 4000g of terephthalic acid, 4000g of 1,4-butanediol, 1g of 2,5-difluoroterephthalic acid, 1g of 3-fluorobenzoic acid, 0.6g of 4-fluorobenzoic acid and 2g of tetrabutyl titanate were added to the system. Nitrogen was used for purging, and the temperature was raised to 190°C. Esterification reaction was carried out at atmospheric pressure. When the amount of water produced by esterification reached the theoretical value, 1800g of PTMEG, 25g of antioxidant 168 and 2g of hollow silica nanoparticles were added. Then the vacuum system was turned on to reduce the pressure to below 100Pa. At the same time, the temperature inside the reactor was raised to 250°C. Waterproof modified polyester was obtained after the reaction.

[0052] In a 20-liter polymerization reactor, 4000g of terephthalic acid, 4000g of 1,4-butanediol, and 2g of tetrabutyl titanate were added to the system. After nitrogen purging, the temperature was raised to 190℃ and the esterification reaction was carried out at atmospheric pressure. When the amount of water produced by esterification reached the theoretical value, 1400g of PEG, 20g of antioxidant 168, and 40g of SIPM were added. Then, the vacuum system was turned on to reduce the pressure to below 100Pa, while the temperature inside the reactor was raised to 250℃. After the reaction, a hygroscopic modified polyester was obtained.

[0053] (2) Waterproof modified polyester and moisture-absorbing modified polyester are injected into a double-layer blown film machine at a mass ratio of 1:6. The temperature of the first zone of the waterproof modified polyester mixing zone is set to 200℃, the temperature of the second zone is 205℃, the temperature of the third zone is 205℃, the temperature of the film outlet is 205℃, the screw speed is 100r / min, the ring blower is turned on, and the traction roller speed is 15m / min. The temperature of the first zone of the moisture-absorbing modified polyester mixing zone is set to 230℃, the temperature of the second zone is 235℃, the temperature of the third zone is 240℃, the temperature of the film outlet is 240℃, the screw speed is 100r / min, the mixing is performed, the ring blower is turned on, and the traction roller speed is 2.5m / min. After winding, a composite film is obtained.

[0054] Example 4 The composite membrane was prepared according to the method described in Example 2, except that the amount of 4-fluorobenzoic acid used in the preparation of the waterproof modified polyester was 1g.

[0055] Example 5 The composite membrane was prepared according to the method described in Example 3, except that the amount of 4-fluorobenzoic acid used in the preparation of the waterproof modified polyester was 1g.

[0056] Example 6 The composite membrane was prepared according to the method described in Example 2, except that the amount of hollow silica nanoparticles used in the preparation of the waterproof modified polyester was 4g.

[0057] Example 7 The composite membrane was prepared according to the method described in Example 3, except that the amount of hollow silica nanoparticles used in the preparation of the waterproof modified polyester was 4g.

[0058] Example 8 The composite membrane was prepared according to the method described in Example 2, except that when preparing the waterproof modified polyester, the amount of 2,5-difluoroterephthalic acid was 6g, the amount of 3-fluorobenzoic acid was 6g, and the amount of 4-fluorobenzoic acid was 3g.

[0059] Example 9 The composite membrane was prepared according to the method described in Example 3, except that when preparing the waterproof modified polyester, the amount of 2,5-difluoroterephthalic acid was 0.8g, the amount of 3-fluorobenzoic acid was 0.8g, and the amount of 4-fluorobenzoic acid was 0.5g.

[0060] Example 10 The composite membrane was prepared according to the method described in Example 1, except that hollow nano-silica particles were replaced with nano-silica particles when preparing the waterproof modified polyester.

[0061] Example 11 The composite membrane was prepared according to the method described in Example 1, except that when preparing the waterproof modified polyester, 2g of 2,5-difluoroterephthalic acid was replaced with 3.6g of 2-fluoroterephthalic acid (CAS No.: 3906-87-4).

[0062] Example 12 The composite membrane was prepared according to the method described in Example 1, except that when preparing the waterproof modified polyester, 2g of 3-fluorobenzoic acid and 1g of 4-fluorobenzoic acid were replaced with 3g of 3-fluorobenzoic acid.

[0063] Example 13 The composite membrane was prepared according to the method described in Example 1, except that when preparing the waterproof modified polyester, 1g of 4-fluorobenzoic acid was replaced with 0.6g of 2,4-difluorobenzoic acid (CAS No.: 1583-58-0).

[0064] Example 14 The composite membrane was prepared according to the method described in Example 1, except that when preparing the waterproof modified polyester, 2g of 2,5-difluoroterephthalic acid was replaced with 1.25g of 2,5-dichloroterephthalic acid (CAS No.: 13799-90-1).

[0065] Example 15 The composite membrane was prepared according to the preparation method described in Example 1, except that when preparing the waterproof modified polyester, 2g of 3-fluorobenzoic acid and 1g of 4-fluorobenzoic acid were replaced with 1.3g of 2,4,6-trifluorobenzoic acid (CAS No.: 28314-80-9).

[0066] Example 16 The composite membrane was prepared according to the preparation method described in Example 2, except that the amount of SIPM used in the preparation of the hygroscopic modified polyester was 90g.

[0067] Example 17 The composite membrane was prepared according to the preparation method described in Example 3, except that the amount of SIPM used in the preparation of the hygroscopic modified polyester was 35g.

[0068] Example 18 The composite membrane was prepared according to the preparation method described in Example 1, except that in step (2), the mass ratio of the waterproof modified polyester to the moisture-absorbing modified polyester was 1:4.

[0069] Example 19 The composite membrane was prepared according to the preparation method described in Example 3, except that in step (2), the mass ratio of the waterproof modified polyester to the moisture-absorbing modified polyester was 1:8.

[0070] Example 20 (1) In a 20-liter polymerization reactor, 4000g of terephthalic acid, 4200g of 1,4-butanediol, 2g of 2,5-difluoroterephthalic acid, 2g of 3-fluorobenzoic acid, 1g of 4-fluorobenzoic acid and 5g of tetrabutyl titanate were added to the system. Nitrogen was used to replace the system, and the temperature was raised to 210°C. The esterification reaction was carried out under normal pressure. When the amount of water produced by esterification reached the theoretical value, 2000g of PTMEG, 25g of antioxidant 1010 and 4g of hollow silica nanoparticles were added. Then the vacuum system was turned on to reduce the pressure to below 100Pa. At the same time, the temperature inside the reactor was raised to 255°C. After the reaction, a waterproof modified polyester was obtained.

[0071] (2) Inject waterproof modified polyester into a blown film machine, set the temperature of zone 1 to 200℃, zone 2 to 205℃, zone 3 to 205℃, the film temperature to 205℃, the screw speed to 100r / min, turn on the ring blower, and set the traction roller speed to 15m / min. After winding, a waterproof modified polyester film is obtained.

[0072] Comparative Example 1 The composite membrane was prepared according to the method described in Example 1, except that 2,5-difluoroterephthalic acid, 3-fluorobenzoic acid and 4-fluorobenzoic acid were not added when preparing the waterproof modified polyester.

[0073] Comparative Example 2 The composite membrane was prepared according to the method described in Example 1, except that 3-fluorobenzoic acid and 4-fluorobenzoic acid were not added when preparing the waterproof modified polyester.

[0074] Comparative Example 3 The composite membrane was prepared according to the method described in Example 1, except that 2,5-difluoroterephthalic acid was not added when preparing the waterproof modified polyester.

[0075] Comparative Example 4 The composite membrane was prepared according to the method described in Example 1, except that PTMEG was not added when preparing the waterproof modified polyester.

[0076] Comparative Example 5 The composite membrane was prepared according to the method described in Example 1, except that hollow silica nanoparticles were not added when preparing the waterproof modified polyester.

[0077] Table 1

[0078] Table 2

[0079] Table 3

[0080] As can be seen from the results in Table 3, the waterproof modified polyester obtained in the embodiments of the present invention simultaneously contains structural units A, B, and C, as well as silica nanoparticles. Comparative Example 1 does not contain structural units A and B, Comparative Example 2 does not contain structural unit B, Comparative Example 3 does not contain structural unit A, Comparative Example 4 does not contain structural unit C, and Comparative Example 5 does not contain silica nanoparticles. The contact angle and water vapor transmission rate of the waterproof modified polyester obtained in the embodiments are higher than those of the comparative examples, indicating that the modified polyester provided by the present invention has better waterproof and breathable properties. In other words, the modified polyester simultaneously contains structural units A, B, and C, as well as silica nanoparticles. Through the interaction of these three structural units and silica nanoparticles, the waterproof and breathable properties of the modified polyester can be improved.

[0081] Furthermore, in the modified polyesters provided in Examples 1-3, the mass ratio of structural unit A to structural unit B (based on fluorine) is 0.85-1:1, while in the modified polyesters provided in Examples 4-5, the mass ratio of structural unit A to structural unit B (based on fluorine) is not within the range of 0.85-1:1. The water vapor transmission rate of Examples 1-3 is higher than that of Examples 4-5, indicating that controlling the mass ratio of structural unit A to structural unit B (based on fluorine) to 0.85-1:1 can further improve the waterproof performance of the modified polyester.

[0082] In the modified polyesters provided in Examples 1-3, the ratio of the total mass of structural unit A and structural unit B (based on fluorine) to the mass of silica nanoparticles (based on silicon) is 0.4-0.7:1. In the modified polyesters provided in Examples 6-7, the mass ratio of structural unit A (based on fluorine) to silica nanoparticles is not within the range of 0.4-0.7:1. The water vapor permeability of Examples 1-3 is higher than that of Examples 6-7, indicating that controlling the ratio of the total mass of structural unit A and structural unit B (based on fluorine) to the mass of silica nanoparticles (based on silicon) to 0.4-0.7:1 can further improve the waterproof performance of the modified polyester.

[0083] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A modified polyester characterized in that, The modified polyester contains structural unit A as shown in formula (I), structural unit B as shown in formula (II), structural unit C as shown in formula (III), and silica nanoparticles. Formula (I), Equation (II), Formula (III) Wherein, R1 and R2 are each independently C1-C6 alkylene groups, X and Y are each independently F or Cl, n is a natural number between 1 and 4, m is a natural number between 1 and 5, and a is a natural number between 15 and 45.

2. The modified polyester according to claim 1, characterized in that, R1 and R2 are each independently C2-C5 alkylene groups, and X and Y are F; Preferably, R1 and R2 are each independently C3-C4 alkylene groups, n=2, m=1, and a is a natural number between 25 and 35.

3. The modified polyester according to claim 1 or 2, characterized in that, In the modified polyester, the total content of structural unit A and structural unit B, calculated as halogen, is 44-305 ppm, preferably 55-245 ppm; the content of silica nanoparticles, calculated as silicon, is 128-365 ppm; and the content of structural unit C is 24-30 wt%. Preferably, the ratio of the total mass of the structural unit A and the structural unit B, calculated as halogen, to the mass of the silica nanoparticles, calculated as silicon, is 0.2-1.1:1, more preferably 0.4-0.7:1; Preferably, the mass ratio of structural unit A to structural unit B, based on halogens, is 0.68-1.2:1, more preferably 0.85-1:1; Preferably, the particle size of the silica nanoparticles is 50-100 nm; Preferably, the silica nanoparticles are hollow silica nanoparticles.

4. A method for producing a modified polyester, characterized by, Includes the following steps: S1. Under esterification conditions, a diacid monomer, a diol monomer, a modified monomer and a catalyst are reacted to obtain a prepolymer. S2. Under polymerization conditions, the prepolymer, the condensate containing the structural unit shown in formula (III), and the silica nanoparticles are brought into contact and reacted. The modified monomer contains a dicarboxylic acid having the structure shown in formula (VIII) and a monocarboxylic acid having the structure shown in formula (II); Formula (VIII) Equation (II), Formula (III) Wherein, R2 is a C1-C6 alkylene group, X and Y are each independently F or Cl, n is a natural number between 1 and 4, m is a natural number between 1 and 5, a is a natural number between 15 and 45, and the diol monomer is a C1-C6 diol.

5. The preparation method according to claim 4, characterized in that, R2 is a C2-C5 alkylene group, X and Y are F, and the diol monomer is a C2-C5 diol; Preferably, R1 is a C3-C4 alkylene group, n=2, m=1, a is a natural number between 25 and 35, and the diol monomer is a C3-C4 diol; Preferably, the particle size of the silica nanoparticles is 50-100 nm; Preferably, the silica nanoparticles are hollow silica nanoparticles.

6. The production method according to claim 4 or 5, characterized by, Based on the theoretical yield of the modified polyester, the total amount of the dicarboxylic acid having the structure shown in formula (VIII) and the monocarboxylic acid having the structure shown in formula (II), calculated as halogen, is 44-305 ppm, more preferably 55-245 ppm; the amount of the silica nanoparticles, calculated as silicon, is 128-365 ppm; and the amount of the condensate containing the structural unit shown in formula (III) is 24-30 wt%. Preferably, the ratio of the total amount of the dicarboxylic acid having the structure shown in formula (VIII) and the monocarboxylic acid having the structure shown in formula (II) based on halogen to the amount of the silica nanoparticles based on silicon is 0.2-1.1:1, more preferably 0.4-0.7:1; Preferably, the ratio of the dicarboxylic acid having the structure shown in formula (VIII) to the monocarboxylic acid having the structure shown in formula (II), based on halogen, is 0.68-1.2:1, more preferably 0.85-1:

1.

7. A modified polyester composite film, characterized by, The device comprises a first film layer and a second film layer bonded together, wherein the first film layer contains a modified polyester as described in any one of claims 1 to 3 or a modified polyester prepared by the preparation method described in any one of claims 4 to 6, and the second film layer contains a copolyester having structural unit D as shown in formula (IV) and structural unit E as shown in formula (V). formula (IV), Formula (V), wherein R A is C1-C4 methylene.

8. The modified polyester composite film according to claim 7, characterized by, In the second film layer, the content of structural unit E is 20-25 wt%, and the content of structural unit D is 0.5-1.3 wt%, preferably 0.56-1.1 wt%. Preferably, the mass ratio of the structural unit D to the structural unit E is 1:20-40, and more preferably 1:22-35; The second membrane layer also contains structural unit F shown in formula (VI) and structural unit G shown in formula (VII); Formula (IV), Formula (V), wherein R B is C1-C4 methyl, Q is a natural number between 0 and 4, and R C is C2-C6 alkylene.

9. The modified polyester composite film according to claim 7 or 8, characterized in that, The thickness of the first film layer is 10-25 μm, preferably 13-23 μm, and the thickness of the second film layer is 80-200 μm, preferably 90-135 μm; Preferably, the thickness ratio of the first film layer to the second film layer is 1:4-8.

10. The use of the modified polyester according to any one of claims 1 to 3, the modified polyester prepared by the preparation method according to any one of claims 7 to 9, or the modified polyester composite film according to any one of claims 4 to 6 in swimwear, protective clothing, waterproof jackets, life jackets, and sleeping bags.

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