Bio-based polybutylene furandicarboxylate blown film and preparation method thereof

Abstract

The invention belongs to the technical field of blown film preparation, and relates to a bio-based poly (butylene furandicarboxylate) blown film and a preparation method thereof, and the blown film is prepared from poly (butylene furandicarboxylate) with specific molecular weight and functional master batch. The preparation method comprises the following steps: step A, preparing polybutylene furandicarboxylate; and step B, preparing the polyfurandicarboxylic acid butanediol blown film. The butanediol furandicarboxylate blown film not only shows excellent thermal stability and mechanical strength, but also has good antibacterial and barrier properties, so that the film is applicable to the fields of food, medicine packaging, agricultural films and the like. The invention aims to provide an environment-friendly high polymer material blown film completely derived from biomass, so as to reduce plastic pollution and provide a sustainable material choice.

Description

Technical Field

[0001] The invention belongs to the technical field of blown films and relates to a furan polyester blown film with excellent comprehensive physical properties, in particular to a bio-based polybutylene furandicarboxylate blown film and a preparation method thereof. Background Art

[0002] Blown film is one of the methods of forming plastic films. The process is to melt and plasticize plastic slices into thin-walled tubes using an extruder. Then, under the action of a traction device, the polymer has a better flow state at this time, and compressed air is used to blow it into the required thickness. After cooling and shaping, it becomes a film. Currently, polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), nylon (PA), etc. are commonly used in blown film applications. Blown film is widely used in containers for packaging food, beverages, cosmetics, medicines and daily necessities, as well as fuel tanks, car shock absorbers, and seat backs in the automotive industry. In addition, blown film is also used in agricultural films, waterproof materials, electronic product packaging and many other fields. Although blown film has good mechanical properties, it cannot meet higher requirements in terms of barrier and antibacterial properties. At the same time, the widespread use of plastic film has also brought environmental problems. Discarded plastic film will pollute the environment. In addition, the plastics used in blown film are basically derived from petrochemical-based polyolefins, polyamides, etc., which are not renewable and do not conform to the sustainable development strategy. Therefore, the promotion of bio-based plastic film derived from biomass is crucial to environmental protection and resource sustainability.

[0003] Polybutylene furandicarboxylate (PBF) is prepared by melt polycondensation of 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol (BDO) by direct esterification. As a new type of furan polyester, it has good comprehensive physical properties, specifically good mechanical strength, impact toughness, thermal stability, barrier properties and antibacterial properties. At the same time, FDCA and BDO are both derived from biomass raw materials, so PBF has significant low-carbon and environmentally friendly characteristics. Summary of the invention

[0004] The present invention proposes a bio-based polybutylene furandicarboxylate blown film and a preparation method thereof, which includes a polymerization process of polybutylene furandicarboxylate and a preparation method of the blown film thereof, mainly regulating the molecular weight of PBF, the thermal processing temperature of the blown film, the blow-up ratio and the thickness thereof; wherein the molecular weight of PBF is regulated by the type and addition amount of the catalyst, the alcohol-acid ratio and the polycondensation reaction time. The preparation process of the PBF blown film proposed by the present invention is simple and efficient, the product performance meets the application requirements, and the production cost is low, which can effectively meet the market demand and has a broad market prospect.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing a bio-based polybutylene furandicarboxylate blown film comprises the following preparation steps: A. Preparation of polybutylene furandicarboxylate The monomers 2,5-furandicarboxylic acid, 1,4-butanediol, a catalyst and a heat stabilizer are added into a polymerization kettle in a certain ratio. After nitrogen is passed to replace the air in the kettle, the temperature is raised and stirred to start the reaction. After a series of reactions such as esterification at normal pressure, pre-polycondensation and final polycondensation, polybutylene furandicarboxylate is prepared.

[0006] B. Preparation of polybutylene furandicarboxylate blown film The dried polybutylene furandicarboxylate (PBF) slices and the opening agent are put into a high-speed mixer in a certain proportion and mixed evenly, and then added into a single-screw extruder film blowing machine, and the screw temperature and the die head temperature are 185~220℃; by adjusting the screw, traction and winding rate, the film's blowing ratio is maintained between 4.0~5.0 to obtain the PBF blown film, and the PBF blown film thickness is controlled between 30~100μm.

[0007] Furthermore, in step A, the monomers 2,5-furandicarboxylic acid and butanediol are derived from biomass with a purity of ≥99.9%, wherein the butanediol is 1,4-butanediol; the catalyst is a titanium catalyst, specifically one of titanium citrate, titanium isopropoxide, tetrabutyl titanate, and tetraethyl titanate; the thermal stabilizer is one of phosphoric acid, triphenyl phosphate, trimethyl phosphate, triphenyl phosphite, and triethyl phosphoacetate, preferably one of phosphoric acid and triethyl phosphoacetate.

[0008] Furthermore, in step A, the molar ratio of monomers is 2,5-furandicarboxylic acid: 1,4-butanediol = 1: (1.5-2.5); the amount of catalyst added is 0.01%-0.2% of the mass of 2,5-furandicarboxylic acid; and the amount of heat stabilizer is 0.05%-0.5% of the mass of 2,5-furandicarboxylic acid.

[0009] Furthermore, in step A, the nitrogen is passed to replace the air in the kettle by passing high-purity nitrogen into the kettle until the gauge pressure reaches 0.8-1.0 MPa, then slowly releasing the pressure, repeating this process 1-3 times, and finally maintaining the nitrogen pressure in the kettle at 20-50 kPa. In the above stirring process, the stirring motor speed is 60-120 r / min in the esterification and pre-polycondensation stages; and 30-50 r / min in the final polycondensation stage.

[0010] Furthermore, in step A, the normal pressure esterification temperature is 155-175°C, the esterification time is 3-4h; the pre-condensation temperature is 185-200°C, the pre-condensation time is 1.0-1.5h, and the polycondensation is performed in a segmented vacuum negative compression manner; the final polycondensation temperature is 210-225°C, the final polycondensation time is 1.5-2.5h, and the vacuum degree is >200pa.

[0011] Furthermore, the intrinsic viscosity of the PBF prepared in step A is 0.83-0.90, and the intrinsic viscosity is tested by the Ubbelohde viscometer method; the solvent is a mixed solvent of phenol and tetrachloroethane, with a mass ratio of 1:1.

[0012] Furthermore, the PBF slices in step B need to be vacuum dried at a drying temperature of 90-120° C. and a drying time of 6-12 hours, and the moisture content of the slices is required to be less than 100 ppm.

[0013] Furthermore, in step B, the opening agent is at least one of silicon dioxide, talc, diatomaceous earth, oleamide, erucamide and EBS derivatives; wherein the amount of the opening agent added is 0.05-0.3% of the mass of the PBF slices.

[0014] Furthermore, in step B, the screw temperature and the die temperature are 185-220°C, preferably the screw zone 1-4 temperatures are 190-220°C, and the die temperature is 220-225°C; wherein the film blowing ratio is maintained between 4.0-5.0, preferably 4.2-4.8, and the film thickness is controlled between 30-100 μm.

[0015] The present invention also provides a bio-based polybutylene furandicarboxylate blown film prepared by the preparation method.

[0016] Therefore, the present invention has the following beneficial effects: the present invention uses bio-based monomers 2,5-furandicarboxylic acid and 1,4-butanediol as raw materials, prepares PBF slices with excellent performance by melt polymerization, and then processes the slices into blown films by screw extrusion blow molding equipment. The PBF blown films have good comprehensive physical properties, specifically including: 1. Good mechanical strength Polybutylene furandicarboxylate (PBF) is prepared from 2,5-furandicarboxylic acid. FDCA has a rigid planar structure, so PBF with a certain molecular weight has good mechanical and physical strength. At the same time, BDO has a long carbon chain and macromolecular flexibility. Compared with polyethylene furandicarboxylate (PEF), its toughness and crystallization rate are greatly improved, which can meet the processing requirements and mechanical strength of blown film.

[0017] 2. Good barrier and antibacterial properties The PBF macromolecular chain contains a large number of furan ring molecular structures. Although the molecular structures of FDCA and PTA are similar, there are also significant differences. Compared with the chemical structure of terephthalic acid, the polarity and nonlinear structure of furan dicarboxylic acid easily lead to difficulty in the flipping of the furan ring. At the same time, the furan ring is smaller and more rigid than the benzene ring. The carbonyl group in the furan polyester oscillates with the EG unit, causing a certain coordinated movement, which in turn slows down the diffusion of gas molecules and has good barrier properties. In addition, the special heterocyclic structure of FDCA can have a significant broad-spectrum antibacterial effect like some furan drugs, and shows good antibacterial properties against Staphylococcus aureus, Escherichia coli, and Candida albicans.

[0018] 3. 100%-bio-based polyester material Polybutylene furandicarboxylate (PBF) is made from furandicarboxylic acid and 1,4-butanediol. Both monomers are derived from biomass and have good renewability. They meet the low-carbon and environmentally friendly sustainable development strategy. The production of one ton of furandicarboxylic acid PBF can reduce carbon emissions by more than 40% compared to petroleum-based polyester PET. The continued development and application of 2,5-furandicarboxylic acid, a monomer derived from biomass, can meet the policy orientation of carbon reduction and emission reduction, thereby promoting sustainable development.

[0019] In summary, the bio-based polybutylene furandicarboxylate blown film prepared in the present invention has excellent thermal stability, barrier properties, mechanical strength and antibacterial effect. At the same time, it is a 100% bio-based material, which meets the strategic principles of sustainable development and low-carbon environmental protection, and provides a new solution for the application scenarios of traditional polyolefin blown films. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the molecular structure of polybutylene furandicarboxylate (PBF); Figure 2 This is a physical picture of PBF slice; Figure 3 is the PBF-DSC curve diagram; Figure 4 This is a physical picture of the PBF blown film prepared in the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be described in detail below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. Overall embodiment

[0022] A method for preparing a bio-based polybutylene furandicarboxylate blown film comprises the following preparation steps: A. Preparation of polybutylene furandicarboxylate The monomer 2,5-furandicarboxylic acid, 1,4-butanediol, catalyst and heat stabilizer are added to the polymerization kettle in a certain ratio, wherein the alcohol-acid ratio is 1.5-2.5, the catalyst addition amount is 0.01%~0.2% of the mass of 2,5-furandicarboxylic acid; the heat stabilizer is 0.05%~0.5% of the mass of 2,5-furandicarboxylic acid. Nitrogen is passed to replace the air in the kettle, and finally the pressure in the kettle is 20~50kpa after nitrogen filling; the circulating heat medium is turned on to heat the polymerization kettle, and the stirring motor is turned on to help the materials mix and react. First, the esterification stage is carried out, the reaction temperature is 155~175℃, the reaction time is 3~4h, the atmospheric pressure in the kettle is maintained, the temperature of the esterification process tower is 90~110℃, and the esterification reaction is completed when the water output reaches 95% of the theoretical value and no more output is produced; then the pre-polycondensation reaction is carried out, the temperature in the kettle is controlled to be 185-200℃, and the staged vacuum negative compression polycondensation is carried out, and the reaction time is 1.0~1.5h; the final polycondensation temperature is 210~225℃, the final polycondensation time is 1.5~2.5h, and the vacuum degree is >200pa. After the reaction, the stirring is stopped, and the nitrogen is passed through the pressurized material to obtain PBF slices.

[0023] B. Preparation of polybutylene furandicarboxylate blown film The PBF slices are vacuum dried at a temperature of 90-120°C and a drying time of 6-12 hours, and the moisture content of the slices is controlled to be less than 100ppm. The dried PBF slices and the opening agent are added to a high-speed mixer in a certain proportion, wherein the amount of the opening agent added is 0.05-0.3% of the mass of the PBF slices; the mixed PBF slices are then added to a single-screw extruder blown film machine, wherein the screw temperature and the head temperature are 185-220°C; by adjusting the screw, traction and winding speed, the film's inflation ratio is maintained between 4.0 and 5.0, and the PBF blown film thickness is controlled between 30 and 100μm. Example 1

[0024] A method for preparing a bio-based polybutylene furandicarboxylate blown film comprises the following preparation steps: A. Preparation of polybutylene furandicarboxylate 25 kg 2,5-furandicarboxylic acid, 26 kg 1,4-butanediol, 15.0 g titanium isopropoxide, 50.0 g triphenyl phosphite were added to the polymerization kettle; after the feeding was completed, the kettle was sealed, nitrogen was passed to replace the air in the kettle, and the process was repeated 3 times, and nitrogen was finally filled as a protective gas at a pressure of 50 kPa; the circulating heat medium was turned on to heat the polymerization kettle, and the stirring motor was turned on to help the materials mix and react. First, the esterification stage was carried out, the temperature in the kettle was controlled to be 160~170℃, the reaction time was 3h, the normal pressure in the kettle was maintained, and the temperature of the esterification process tower was 90~100℃. When the water output reached 95% of the theoretical value and no more output was produced, the esterification reaction was completed; then the pre-condensation reaction was carried out, the temperature in the kettle was controlled to be 195-200℃, and the staged vacuum negative compression polymerization was carried out for a reaction time of 1.5h; the final condensation temperature was 220~225℃, the final condensation time was 2h, and the vacuum degree was controlled above 70pa. After the reaction is completed, stirring is stopped, and nitrogen is passed through to pressurize the material and granulate to obtain PBF slices.

[0025] B. Preparation of polybutylene furandicarboxylate blown film The PBF slices prepared above were vacuum dried at a drying temperature of 120°C and a drying time of 8 hours to ensure that the slices contained less than 100 ppm of water. They were then put into a high-speed mixer with an opening agent, silicon dioxide, in a certain proportion, wherein the amount of the opening agent added was 0.1% of the mass of the PBF slices. The mixed PBF slices were added into a single-screw extruder film blowing machine, wherein the temperatures of the screw zones 1 to 4 were 190 to 220°C, respectively, and the die temperature was 220 to 225°C. The film's blowing ratio was maintained at about 4.5, and the film thickness was controlled between 50 and 60 μm. Example 2

[0026] A. Preparation of polybutylene furandicarboxylate Add 25 kg 2,5-furandicarboxylic acid, 26 kg 1,4-butanediol, 15.0 g tetrabutyl titanate, and 50.0 g triphenyl phosphite into the polymerization kettle; after the feeding is completed, seal it, replace the air in the kettle with nitrogen, repeat 1-3 times, and finally fill it with nitrogen as a protective gas, with a pressure of 50 kPa; turn on the circulating heat medium to heat the polymerization kettle, and turn on the stirring motor to help the materials mix and react. First, the esterification stage is carried out, the temperature in the kettle is controlled to 160~170℃, the reaction time is 3h, the normal pressure in the kettle is maintained, the temperature of the esterification process tower is 90~100℃, and the esterification reaction is completed when the water output reaches 95% of the theoretical value and no more output is produced; then the pre-condensation reaction is carried out, the temperature in the kettle is controlled to 195-200℃, and the staged vacuum negative compression polymerization is carried out, and the reaction time is 1.5h; the final condensation temperature is 220~225℃, the final condensation time is 2h, and the vacuum degree is controlled above 70pa. After the reaction is completed, stirring is stopped, and nitrogen is passed through to pressurize the material and granulate to obtain PBF slices.

[0027] B. Preparation of polybutylene furandicarboxylate blown film Processing technology is the same as Example 1 Example 3

[0028] A. Preparation of polybutylene furandicarboxylate Add 25 kg 2,5-furandicarboxylic acid, 21.6 kg 1,4-butanediol, 15.0 g tetrabutyl titanate, and 50.0 g triphenyl phosphite into the polymerization kettle; after the feeding is completed, seal it, replace the air in the kettle with nitrogen, repeat 1-3 times, and finally fill it with nitrogen as a protective gas, with a pressure of 50 kpa; turn on the circulating heat medium to heat the polymerization kettle, and turn on the stirring motor to help the materials mix and react. First, the esterification stage is carried out, the temperature in the kettle is controlled to 160~170℃, the reaction time is 3h, the normal pressure in the kettle is maintained, the temperature of the esterification process tower is 90~100℃, and the esterification reaction is completed when the water output reaches 95% of the theoretical value and no more output is produced; then the pre-condensation reaction is carried out, the temperature in the kettle is controlled to 195-200℃, and the staged vacuum negative compression polymerization is carried out, and the reaction time is 1.5h; the final condensation temperature is 220~225℃, the final condensation time is 2h, and the vacuum degree is controlled above 70pa. After the reaction is completed, stirring is stopped, and nitrogen is passed through to pressurize the material and granulate to obtain PBF slices.

[0029] B. Preparation of polybutylene furandicarboxylate blown film Processing technology is the same as Example 1 Example 4

[0030] A. Preparation of polybutylene furandicarboxylate Add 25 kg 2,5-furandicarboxylic acid, 28.8 kg 1,4-butanediol, 15.0 g tetrabutyl titanate, and 50.0 g triphenyl phosphite into the polymerization kettle; after the feeding is completed, seal it, replace the air in the kettle with nitrogen, repeat 1-3 times, and finally fill it with nitrogen as a protective gas, with a pressure of 50 kpa; turn on the circulating heat medium to heat the polymerization kettle, and turn on the stirring motor to help the materials mix and react. First, the esterification stage is carried out, the temperature in the kettle is controlled to 160~170℃, the reaction time is 3h, the normal pressure in the kettle is maintained, the temperature of the esterification process tower is 90~100℃, and the esterification reaction is completed when the water output reaches 95% of the theoretical value and no more output is produced; then the pre-condensation reaction is carried out, the temperature in the kettle is controlled to 195-200℃, and the vacuum is vacuumed and compressed in sections, and the reaction time is 1.5h; the final condensation temperature is 220~225℃, the final condensation time is 2h, and the vacuum degree is controlled above 70pa. After the reaction is completed, stirring is stopped, and nitrogen is passed through to pressurize the material and granulate to obtain PBF slices.

[0031] B. Preparation of polybutylene furandicarboxylate blown film The processing technology is the same as that of Example 1. Example 5

[0032] Preparation of polybutylene furandicarboxylate The preparation process is the same as in Example 1 B. Preparation of polybutylene furandicarboxylate blown film The PBF slices prepared above were vacuum dried at 120°C for 8 hours to ensure that the slices contained less than 100ppm of water. Then, they were added to a high-speed mixer with an opening agent, oleic acid amide, in a certain proportion, wherein the amount of the opening agent added was 0.1% of the mass of the PBF slices. The mixed PBF slices were added to a single-screw extruder film blowing machine, and the temperatures of the screw zones 1 to 4 were 190 to 220°C, respectively, and the die temperature was 220 to 225°C. The film's blowing ratio was maintained at 4.5, and the film thickness was controlled at 50 to 60μm. Example 6

[0033] A Preparation of polybutylene furandicarboxylate The preparation process is the same as in Example 1 B. Preparation of polybutylene furandicarboxylate blown film The PBF slices prepared above were vacuum dried at 120°C for 8 hours to ensure that the slices contained less than 100ppm of water. They were then put into a high-speed mixer with an opening agent, oleic acid amide, in a certain proportion, wherein the amount of the opening agent added was 0.1% of the mass of the PBF slices. The mixed PBF slices were added into a single-screw extruder film blowing machine, and the temperatures of the screw zones 1 to 4 were 190 to 220°C, respectively, and the die temperature was 220 to 225°C. The film's blowing ratio was maintained at 4.0, and the film thickness was controlled at 70 to 80μm. Example 7

[0034] A Preparation of polybutylene furandicarboxylate Processing technology is the same as Example 1 B. Preparation of polybutylene furandicarboxylate blown film The PBF slices prepared above were vacuum dried at 120°C for 8 hours to ensure that the slices contained less than 100ppm of water. They were then put into a high-speed mixer with the opening agent oleic acid amide in a certain proportion, wherein the amount of the opening agent added was 0.1% of the mass of the PBF slices. The mixed PBF slices were added into a single-screw extruder film blowing machine, and the temperatures of the screw zones 1 to 4 were 190 to 220°C, respectively, and the die temperature was 220 to 225°C. The film's blowing ratio was maintained at 5.0, and the film thickness was controlled at 40 to 50μm. Comparative Example 1

[0035] A. Preparation of polybutylene furandicarboxylate Add 25 kg 2,5-furandicarboxylic acid, 20.2 kg 1,4-butanediol, 15.0 g titanium isopropoxide, and 50.0 g triphenyl phosphite into the polymerization kettle; after the feeding is completed, seal it, replace the air in the kettle with nitrogen, repeat 1-3 times, and finally fill it with nitrogen as a protective gas, with a pressure of 50 kpa; turn on the circulating heat medium to heat the polymerization kettle, and turn on the stirring motor to help the materials mix and react. First, the esterification stage is carried out, the temperature in the kettle is controlled to 160~170℃, the reaction time is 3h, the normal pressure in the kettle is maintained, the temperature of the esterification process tower is 90~100℃, and the esterification reaction is completed when the water output reaches 95% of the theoretical value and no more output is produced; then the pre-condensation reaction is carried out, the temperature in the kettle is controlled to 195-200℃, and the staged vacuum negative compression polymerization is carried out, and the reaction time is 1.5h; the final condensation temperature is 220~225℃, the final condensation time is 2h, and the vacuum degree is controlled above 70pa. After the reaction is completed, stirring is stopped, and nitrogen is passed through to pressurize the material and granulate to obtain PBF slices.

[0036] B. Preparation of polybutylene furandicarboxylate blown film Processing technology is the same as Example 1 Comparative Example 2

[0037] A. Preparation of polybutylene furandicarboxylate Add 25 kg 2,5-furandicarboxylic acid, 26 kg 1,4-butanediol, 15.0 g ethylene glycol antimony, and 50.0 g triphenyl phosphite into the polymerization kettle; after the feeding is completed, seal it, replace the air in the kettle with nitrogen, repeat 1-3 times, and finally fill it with nitrogen as a protective gas, with a pressure of 50 kpa; turn on the circulating heat medium to heat the polymerization kettle, and turn on the stirring motor to help the materials mix and react. First, the esterification stage is carried out, the temperature in the kettle is controlled to 160~170℃, the reaction time is 3h, the normal pressure in the kettle is maintained, the temperature of the esterification process tower is 90~100℃, and the esterification reaction is completed when the water output reaches 95% of the theoretical value and no more output is produced; then the pre-condensation reaction is carried out, the temperature in the kettle is controlled to 195-200℃, and the staged vacuum negative compression polymerization is carried out, and the reaction time is 1.5h; the final condensation temperature is 220~225℃, the final condensation time is 2h, and the vacuum degree is controlled above 70pa. After the reaction is completed, stirring is stopped, and nitrogen is passed through to pressurize the material and granulate to obtain PBF slices.

[0038] B. Preparation of polybutylene furandicarboxylate blown film Processing technology is the same as Example 1 Comparative Example 3

[0039] A method for preparing a polybutylene furandicarboxylate blown film comprises the following preparation steps: A. Preparation of polybutylene furandicarboxylate Add 25 kg 2,5-furandicarboxylic acid, 17.9 kg ethylene glycol, 15.0 g titanium isopropoxide, and 50.0 g triphenyl phosphite into the polymerization kettle; after the feeding is completed, seal it, replace the air in the kettle with nitrogen, repeat 1-3 times, and finally fill it with nitrogen as a protective gas, with a pressure of 50 kpa; turn on the circulating heat medium to heat the polymerization kettle, and turn on the stirring motor to help the materials mix and react. First, the esterification stage is carried out, the temperature in the kettle is controlled to 160~170℃, the reaction time is 3h, the normal pressure in the kettle is maintained, the temperature of the esterification process tower is 90~100℃, and the esterification reaction is completed when the water output reaches 95% of the theoretical value and no more output is produced; then the pre-condensation reaction is carried out, the temperature in the kettle is controlled to 195-200℃, and the staged vacuum negative compression polymerization is carried out, and the reaction time is 1.5h; the final condensation temperature is 220~225℃, the final condensation time is 2h, and the vacuum degree is controlled above 70pa. After the reaction is completed, stirring is stopped, and nitrogen is passed through to pressurize the material and granulate to obtain PBF slices.

[0040] B. Preparation of polybutylene furandicarboxylate blown film Processing technology is the same as Example 1 Comparative Example 4

[0041] Commercially available PP, manufacturer China Taiwan Plastic Brand No. 2020S, the processing technology of the blown film is the same as that of Example 1.

[0042] The above-mentioned embodiments and comparative examples were analyzed, and the prepared PBF slices and blown films were tested for performance. The intrinsic viscosity was measured in accordance with the standard GB / T 14190-2008; the gas barrier performance was measured in accordance with the standard GB / T 1038-2000; the tensile mechanical properties were measured in accordance with the standard GB / T 1040.1-2018; the antibacterial rate was measured in accordance with the standard GB20944.3-2008-T, and the bacteria were Staphylococcus aureus; the glass transition and melting point were measured by differential scanning calorimetry (DSC), and the test conditions were: nitrogen atmosphere, flow rate 20ml / min; the sample temperature was increased from 30°C to 280°C, the heating rate was 20°C / min, kept warm for 3 minutes, cooled to 30°C, the cooling rate was 10°C / min; kept warm for 3 minutes, and then increased from 30°C to 280°C again, the heating rate was 10°C / min. The data are as follows:

[0043] In Examples 1-5 of the present invention, polybutylene furandicarboxylate (PBF) with a certain molecular weight was successfully prepared by melt polymerization using 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol as monomers. By comparing the processes such as catalyst and alcohol-acid ratio, the results show that the polymerization processes involved in the present invention can all prepare furan polyester PBF with good performance, and its intrinsic viscosity is all greater than 0.85. In Examples 5-7, the preparation processes of PBF blown films were compared, and the results show that the type of opening agent and the blowing ratio will have a certain influence on the physical properties of the PBF blown film, but its overall performance All of them can maintain good physical properties; in the comparative example, the addition amount of FDCA and BDO was greatly adjusted, and the results showed that too low or too high alcohol-acid ratio could not produce PBF slices with higher molecular weight. At the same time, polyethylene furandicarboxylate was synthesized in comparative example 3, but it could not be processed by blow molding because of its obvious hard and brittle mechanical properties; in comparative example 4, a blown film was prepared by extrusion blow molding of commercially available polypropylene (PP) resin. By comparing its physical properties, it can be found that the PBF blown film has better mechanical and physical strength, and excellent barrier and antibacterial properties, and can be used as a packaging film. Figures 1 to 4 The PBF molecular structure, physical photos, DSC data graphs and physical photos of PBF blown film are displayed respectively.

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a bio-based polybutylene furandicarboxylate blown film, characterized in that: The method comprises the following preparation steps: A. Preparation of polybutylene furandicarboxylate The monomer 2,5-furandicarboxylic acid, butanediol, catalyst and heat stabilizer are added into a polymerization kettle in a certain ratio, and the air in the kettle is replaced by nitrogen, and the temperature is raised and stirred to start the reaction. After a series of reactions including esterification at normal pressure, pre-polycondensation and final polycondensation, polybutylene furandicarboxylate (PBF) is prepared. B. Preparation of polybutylene furandicarboxylate blown film The dried polybutylene furandicarboxylate (PBF) slices and the opening agent are put into a high-speed mixer in a certain proportion and mixed evenly, and then added into a single-screw extruder film blowing machine, and the screw temperature and the die head temperature are 185~220℃; by adjusting the screw, traction and winding rate, the film's blowing ratio is maintained at 4.0~5.0 to obtain the PBF blown film, and the PBF blown film thickness is controlled at 30~100μm.

2. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 1, characterized in that: In step A, the monomers 2,5-furandicarboxylic acid and butanediol are derived from biomass with a purity of ≥99.9%, wherein the butanediol is 1,4-butanediol; the catalyst is a titanium catalyst, specifically one of titanium citrate, titanium isopropoxide, tetrabutyl titanate, and tetraethyl titanate; the thermal stabilizer is one of phosphoric acid, triphenyl phosphate, trimethyl phosphate, triphenyl phosphite, and triethyl phosphoacetate, preferably one of phosphoric acid and triethyl phosphoacetate.

3. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 2, characterized in that: In step A, the molar ratio of monomers is 2,5-furandicarboxylic acid: 1,4-butanediol = 1: (1.5-2.5); the amount of catalyst added is 0.01%-0.2% of the mass of 2,5-furandicarboxylic acid; and the amount of heat stabilizer is 0.05%-0.5% of the mass of 2,5-furandicarboxylic acid.

4. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 1, characterized in that: In step A, the nitrogen is passed to replace the air in the kettle by introducing high-purity nitrogen into the kettle until the gauge pressure reaches 0.8-1.0 MPa and then slowly releasing the pressure, repeating this process 1-3 times, and finally maintaining the nitrogen pressure in the kettle at 20-50 kPa; in the above stirring process, the speed of the stirring motor is 60-120 r / min in the esterification and pre-polycondensation stages; and 30-50 r / min in the final polycondensation stage.

5. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 1, characterized in that: In step A, the normal pressure esterification temperature is 155-175° C., the esterification time is 3-4 hours; the pre-condensation temperature is 185-200° C., the pre-condensation time is 1.0-1.5 hours, and the polycondensation is performed in a segmented vacuum negative compression manner; the final polycondensation temperature is 210-225° C., the final polycondensation time is 1.5-2.5 hours, and the vacuum degree is >200 Pa.

6. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 1, characterized in that: The intrinsic viscosity of the PBF prepared in step A is 0.83-0.90, and the intrinsic viscosity is tested by the Ubbelohde viscometer method; the solvent is a mixed solvent of phenol and tetrachloroethane, with a mass ratio of 1:

1.

7. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 1, characterized in that: The PBF slices in step B need to be vacuum dried at a temperature of 90-120°C and a drying time of 6-12 hours. The moisture content of the slices is required to be less than 100 ppm.

8. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 1, characterized in that: In step B, the opening agent is at least one of silicon dioxide, talc, diatomaceous earth, oleamide, erucamide and EBS derivatives; wherein the amount of the opening agent added is 0.05-0.3% of the mass of the PBF slice.

9. The method for preparing a bio-based polybutylene furandicarboxylate blown film according to claim 1, characterized in that: In step B, the screw temperature and die temperature are 185-220°C, preferably the screw zone 1-4 temperature are 190-220°C, and the die temperature is 220-225°C; wherein the film blowing ratio is maintained between 4.0-5.0, preferably 4.2-4.8, and the film thickness is controlled between 30-100 μm.

10. A bio-based polybutylene furandicarboxylate blown film, characterized in that: The method is prepared according to any one of claims 1 to 9.

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