Polyester material with excellent thermal stability and optical transmittance and preparation thereof

Abstract

The invention discloses a polyester material with excellent thermal stability and optical transmittance, the structural formula of the polyester material is # imgabs0 #, and n: m = (0: 100)-(100: 0). The preparation method of the polyester material comprises the following steps: heating terephthalic acid, an alcoholic solution, a catalyst and an additive to 50-100 DEG C in a nitrogen environment, and pulping to be uniform; raising the temperature to 150-220 DEG C, and carrying out esterification reaction until the esterification rate reaches 95% or above; vacuumizing to 100 Pa or below, heating to 230-260 DEG C, and carrying out condensation polymerization for 2-3 hours; and adding isosorbide, heating to 260-270 DEG C, reacting for 20-60 minutes, discharging, crushing and drying to obtain the target product. The polyester material prepared in the invention has good thermal stability and optical transmittance.

Description

Technical Field

[0001] The invention relates to the technical field of polyester materials, and in particular to a polyester material with excellent thermal stability and optical transmittance and a preparation method thereof. Background Art

[0002] The polyester film currently on the market is a polymer film material with excellent comprehensive performance. Polyester film material has excellent physical and chemical properties and is widely used in the fields of electronics, electrical appliances and photosensitive materials.

[0003] The British Imperial Chemical Company (ICI) and the American DuPont Company first applied polyester film in 1948 and achieved industrial production of biaxially oriented polyester film (POPET) in 1953.

[0004] Polyethylene terephthalate-co-poly(1,4-cyclohexanedimethanol terephthalate) (PETG, PCTG) is a new type of engineering plastic, which is widely used in high-transparent sheets, heat-sealing films, and bottle materials. For example, the heat shrinkage rate of polyethylene terephthalate (PET) is only 30%, while the heat shrinkage rate of PETG is as high as 70%, which can be used for packaging of containers with complex shapes. However, due to its poor thermal stability, during the preparation and processing process, the polyester material is often oxidized, the prepared product turns yellow, and the optical transmittance becomes poor.

[0005] The terminal carboxyl content of polyester materials is an important indicator for characterizing polyester materials. The terminal carboxyl content directly affects the thermal stability of polyester products. In order to obtain polyester materials with good thermal stability, the polycondensation temperature should be reduced as much as possible during the polycondensation process, and the polycondensation reaction time should be reduced. The above two methods for reducing the terminal carboxyl content of polyester materials often result in the prepared polyester materials having too low relative molecular weight and uneven molecular weight distribution, which affects the application fields of the products, such as bottle materials, films, fibers, etc.

[0006] In summary, the prior art lacks polyester film materials with good thermal stability and excellent optical transmittance. Summary of the invention

[0007] In order to overcome the above problems, the present invention provides a polyester material with excellent thermal stability and optical transmittance and its preparation method.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] The present invention discloses a polyester material having excellent thermal stability and optical transmittance, wherein the polyester material has the following structural formula:

[0010]

[0011] Among them, n:m=(0:100)~(100:0).

[0012] A method for preparing a polyester material of the present invention comprises the following steps:

[0013] 1) Put terephthalic acid, alcohol solution, catalyst and additive into a reactor, heat to 50-100° C. under nitrogen environment, and beat until the mixed liquid is uniform;

[0014] 2) raising the temperature in the reactor to 150-220° C. to carry out esterification reaction until the esterification rate reaches more than 95%;

[0015] 3) After the reactor is evacuated to a vacuum of less than 100 Pa, the temperature is raised to 230-260° C. and polycondensation reaction is carried out for 2-3 hours;

[0016] 4) After the polycondensation reaction is completed, isosorbide is added into the reactor, the temperature is raised to 260-270° C., the reaction is carried out for 20-60 minutes, and then the target product is obtained after discharging, crushing and drying;

[0017] The alcohol solution is selected from ethylene glycol or 1,4-cyclohexanedimethanol;

[0018] The catalyst is selected from dimethyl tin oxide, tin acetate, tetraethoxy titanium, tetrabutyl titanate, tetraisopropyl titanate, ethylene glycol titanium, 1,3-propylene glycol titanium, antimony trioxide, ethylene glycol antimony, butanediol antimony or 1,3-propylene glycol antimony;

[0019] The additives include stabilizers and antioxidants. The stabilizer is selected from one or more of phosphoric acid, alkyl phosphates, triphenyl phosphate, and alkyl diaryl phosphates; the antioxidant is selected from one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester (antioxidant 1010), 4,4'-thiobis(6-tert-butyl-3-methylphenol) (antioxidant 300), tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168), and hexanediol antimony.

[0020] The molar ratio of terephthalic acid to the alcohol solution is 1:1.2-1.6; the amount of the catalyst is 0.1‰-0.5‰ of the molar number of terephthalic acid; the amount of the stabilizer is 0.1‰-0.5‰ of the molar number of terephthalic acid; the amount of the antioxidant is 0.1‰-0.5‰ of the molar number of terephthalic acid; and the amount of isosorbide is 1%-10% of the molar number of terephthalic acid.

[0021] Beneficial effects:

[0022] The present invention uses isosorbide as a capping agent to prepare a polyester film material with good thermal stability and excellent optical transmittance. The thermal stability of the prepared polyester material is significantly improved, and its 5% thermal weight loss temperature range is above 400°C, which is significantly higher than the thermal stability of the current commercial polyester materials (T5% of PET is 370°C, and T5% of PETG / PCTG is 375°C). At the same time, the prepared polyester material has excellent optical transmittance, which is expected to expand its promotion in the film field. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the embodiments.

[0024] Example 1

[0025] Put the raw materials (50g terephthalic acid, 13g ethylene glycol, 30g 1,4-cyclohexanedimethanol), catalyst (41mg tetrabutyl titanate), additives (39mg triphenyl phosphate, 141mg antioxidant 1010) into the reactor, and use an overhead mechanical stirring device. Replace the air in the container with nitrogen 3-5 times at room temperature. Maintain a nitrogen atmosphere at 50-100℃ and perform pulping. When the catalyst, additives and raw materials are evenly mixed, the reaction system is heated to 150-220℃ and enters the esterification stage. When the slurry in the reactor becomes clear and transparent, maintain it for 30-60min to ensure that the esterification rate reaches more than 95%. When the esterification rate reaches the requirement, slowly evacuate the vacuum, and the pressure in the reactor gradually decreases. After 20-60min, the vacuum degree in the reactor reaches below 100Pa, and the temperature is raised to 230-260℃. The vacuum degree of the reactor is maintained below 100Pa, and the reaction is carried out for 2-3h, and the polycondensation reaction is completed. After the polycondensation reaction is completed, 0.44 g of isosorbide is added, the reaction system is maintained at 260-270°C, and the reaction is carried out for 20-60 minutes. The material is discharged, powdered, and dried to obtain polyester.

[0026] Example 2

[0027] Put the raw materials (50g terephthalic acid, 13g ethylene glycol, 30g 1,4-cyclohexanedimethanol), catalyst (41mg tetrabutyl titanate), additives (39mg triphenyl phosphate, 141mg antioxidant 1010) into the reactor, and use an overhead mechanical stirring device. Replace the air in the container with nitrogen 3-5 times at room temperature. Maintain a nitrogen atmosphere at 50-100℃ and perform pulping. When the catalyst, additives and raw materials are evenly mixed, the reaction system is heated to 150-220℃ and enters the esterification stage. When the slurry in the reactor becomes clear and transparent, maintain it for 30-60min to ensure that the esterification rate reaches more than 95%. When the esterification rate reaches the requirement, slowly evacuate the vacuum, and the pressure in the reactor gradually decreases. After 20-60min, the vacuum degree in the reactor reaches below 100Pa, and the temperature is raised to 230-260℃. The vacuum degree of the reactor is maintained below 100Pa, and the reaction is carried out for 2-3h, and the polycondensation reaction is completed. After the polycondensation reaction is completed, 0.88g of isosorbide is added, and the reaction system is maintained at 260-270°C for 20-60 minutes. The material is discharged, powdered, and dried to obtain polyester.

[0028] Example 3

[0029] Put the raw materials (50g terephthalic acid, 13g ethylene glycol, 30g 1,4-cyclohexanedimethanol), catalyst (41mg tetrabutyl titanate), additives (39mg triphenyl phosphate, 141mg antioxidant 1010) into the reactor, and use an overhead mechanical stirring device. Replace the air in the container with nitrogen 3-5 times at room temperature. Maintain a nitrogen atmosphere at 50-100℃ and perform pulping. When the catalyst, additives and raw materials are evenly mixed, the reaction system is heated to 150-220℃ and enters the esterification stage. When the slurry in the reactor becomes clear and transparent, maintain it for 30-60min to ensure that the esterification rate reaches more than 95%. When the esterification rate reaches the requirement, slowly evacuate the vacuum, and the pressure in the reactor gradually decreases. After 20-60min, the vacuum degree in the reactor reaches below 100Pa, and the temperature is raised to 230-260℃. The vacuum degree of the reactor is maintained below 100Pa, and the reaction is carried out for 2-3h, and the polycondensation reaction is completed. After the polycondensation reaction is completed, 1.32 g of isosorbide is added, the reaction system is maintained at 260-270°C, and the reaction is carried out for 20-60 minutes. The material is discharged, powdered, and dried to obtain polyester.

[0030] Example 4

[0031] Put the raw materials (50g terephthalic acid, 13g ethylene glycol, 30g 1,4-cyclohexanedimethanol), catalyst (41mg tetrabutyl titanate), additives (39mg triphenyl phosphate, 141mg antioxidant 1010) into the reactor, and use an overhead mechanical stirring device. Replace the air in the container with nitrogen 3-5 times at room temperature. Maintain a nitrogen atmosphere at 50-100℃ and perform pulping. When the catalyst, additives and raw materials are evenly mixed, the reaction system is heated to 150-220℃ and enters the esterification stage. When the slurry in the reactor becomes clear and transparent, maintain it for 30-60min to ensure that the esterification rate reaches more than 95%. When the esterification rate reaches the requirement, slowly evacuate the vacuum, and the pressure in the reactor gradually decreases. After 20-60min, the vacuum degree in the reactor reaches below 100Pa, and the temperature is raised to 230-260℃. The vacuum degree of the reactor is maintained below 100Pa, and the reaction is carried out for 2-3h, and the polycondensation reaction is completed. After the polycondensation reaction is completed, 1.76 g of isosorbide is added, the reaction system is maintained at 260-270°C, and the reaction is carried out for 20-60 minutes. The material is discharged, powdered, and dried to obtain polyester.

[0032] Example 5

[0033] Put the raw materials (50g terephthalic acid, 13g ethylene glycol, 30g 1,4-cyclohexanedimethanol), catalyst (41mg tetrabutyl titanate), additives (39mg triphenyl phosphate, 141mg antioxidant 1010) into the reactor, and use an overhead mechanical stirring device. Replace the air in the container with nitrogen 3-5 times at room temperature. Maintain a nitrogen atmosphere at 50-100℃ and perform pulping. When the catalyst, additives and raw materials are evenly mixed, the reaction system is heated to 150-220℃ and enters the esterification stage. When the slurry in the reactor becomes clear and transparent, maintain it for 30-60min to ensure that the esterification rate reaches more than 95%. When the esterification rate reaches the requirement, slowly evacuate the vacuum, and the pressure in the reactor gradually decreases. After 20-60min, the vacuum degree in the reactor reaches below 100Pa, and the temperature is raised to 230-260℃. The vacuum degree of the reactor is maintained below 100Pa, and the reaction is carried out for 2-3h, and the polycondensation reaction is completed. After the polycondensation reaction is completed, 2.2 g of isosorbide is added, the reaction system is maintained at 260-270°C, and the reaction is carried out for 20-60 minutes. The material is discharged, powdered, and dried to obtain polyester.

[0034] The polyester materials obtained in Examples 1 to 5 were subjected to thermal stability tests, and the test results are shown in Table 1.

[0035] Table 1

[0036] 5% decomposition temperature Td, 5% (℃) Example 1 405 Example 2 403 Example 3 407 Example 4 404 Example 5 406

[0037] It can be seen from Table 1 that the polyesters prepared by the method of the present invention, in Examples 1 to 5, all have 5% decomposition temperatures as high as 400° C. or above, and have excellent thermal stability.

[0038] The polyester materials obtained in Examples 1 to 5 were tested for optical properties. The test results are shown in Table 2.

[0039] Table 2

[0040] Optical transmittance at 800nm ​​wavelength (%) Example 1 87 Example 2 88 Example 3 86 Example 4 88 Example 5 84

[0041] It can be seen from Table 2 that the polyester prepared by the method of the present invention has excellent optical transmittance.

Claims

1. A polyester material having excellent thermal stability and optical transmittance, characterized in that: The polyester material has the following structural formula: Among them, n:m=(0:100)~(100:0).

2. A method for preparing a polyester material, characterized in that: The specific preparation method comprises the following steps: 1) Put terephthalic acid, alcohol solution, catalyst and additive into a reactor, heat to 50-100° C. under nitrogen environment, and beat until the mixed liquid is uniform; 2) raising the temperature in the reactor to 150-220° C. to carry out esterification reaction until the esterification rate reaches more than 95%; 3) After the reactor is evacuated to a vacuum of less than 100 Pa, the temperature is raised to 230-260° C. and polycondensation reaction is carried out for 2-3 hours; 4) After the polycondensation reaction is completed, isosorbide is added into the reactor, the temperature is raised to 260-270° C., the reaction is carried out for 20-60 minutes, and then the target product is obtained after discharging, crushing and drying; The alcohol solution is selected from ethylene glycol or 1,4-cyclohexanedimethanol; The catalyst is selected from dimethyl tin oxide, tin acetate, tetraethoxy titanium, tetrabutyl titanate, tetraisopropyl titanate, ethylene glycol titanium, 1,3-propylene glycol titanium, antimony trioxide, ethylene glycol antimony, butanediol antimony or 1,3-propylene glycol antimony; The additives include stabilizers and antioxidants, wherein the stabilizer is selected from one or more of phosphoric acid, alkyl phosphates, triphenyl phosphate, and alkyl diaryl phosphates; the antioxidant is selected from one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester (antioxidant 1010), 4,4'-thiobis(6-tert-butyl-3-methylphenol) (antioxidant 300), tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168), and hexanediol antimony; The molar ratio of terephthalic acid to the alcohol solution is 1:1.2-1.6; the amount of the catalyst is 0.1‰-0.5‰ of the molar number of terephthalic acid; the amount of the stabilizer is 0.1‰-0.5‰ of the molar number of terephthalic acid; the amount of the antioxidant is 0.1‰-0.5‰ of the molar number of terephthalic acid; and the amount of isosorbide is 1%-10% of the molar number of terephthalic acid.

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