A high barrier performance PBAT composition, preparation method and application

Abstract

The present invention belongs to the technical field of preparing polymer material composition films, and specifically relates to a high-barrier PBAT composition, preparation method, and application. The high-barrier PBAT composition comprises the following components, measured by mass: 100 parts of PBAT, 2-20 parts of polyoxalate, 1-5 parts of a carboxyl end remover, an antioxidant (0.1-0.5 parts), and a compatibilizer (0.2-0.6 parts). The polyoxalate is selected from at least one of polyethylene oxalate and polybutylene oxalate. The film sample prepared by the present invention has high gas barrier properties and can be used as a fresh-keeping film for fruits and foods, showing good market prospects and transformational implementation value.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparing polymer material composition films, and specifically relates to a method for preparing a PBAT composition film with high barrier properties. Background Art

[0002] Polybutylene terephthalate-adipate (PBAT) is widely used in everyday applications, such as packaging bags and agricultural films, due to its excellent ductility and degradation resistance. However, despite its widespread application, PBAT's poor barrier and mechanical properties often prevent its application in food preservation applications. This limits its market adoption. Therefore, the design and development of PBAT film materials with high barrier properties suitable for food preservation applications has become an effective approach to expanding PBAT's application scope.

[0003] Therefore, if PBAT is to be given high barrier properties, its mechanical strength is to be improved, and its economic efficiency is to be increased, it still needs to be modified. Among them, blending modification is a commonly used process route for material modification in the polyester field. However, the blending process of PBAT materials and other modified materials often results in phase separation, which results in the inability of the blended materials to be smoothly blown into films. How to blend and modify PBAT, solve the poor compatibility between the blended raw materials, the phase separation problem, and the problem that the blended composition cannot be smoothly blown into a film, while further improving the mechanical properties and barrier properties of the PBAT material, is the main problem to be solved in this application. Summary of the Invention

[0004] In order to solve the shortcomings of existing PBAT materials such as poor barrier properties, insufficient mechanical strength and poor compatibility when blended, the present invention provides a high-barrier performance PBAT composition, preparation method and application.

[0005] In a first aspect, the present invention provides a high barrier performance PBAT composition, which comprises the following components in parts by mass:

[0006]

[0007] The PBAT is polybutylene terephthalate adipate, and its structural formula is:

[0008]

[0009] Wherein, x is the number of butylene terephthalate structural units in PBAT, y is the number of butylene adipate structural units in PBAT, n is the degree of polymerization of PBAT, x, y, and n are all natural numbers, 150<n<200; and the polyoxalate is selected from at least one of polyethylene oxalate (PEOx) and polybutylene oxalate (PBOx).

[0010] Preferably, the molar ratio of x to y is 6:(4-9).

[0011] Preferably, the molar ratio of x to y is 45:55, 47:53, or 50:50.

[0012] Preferably, the PEOx structural formula is:

[0013]

[0014] Wherein, p is the number of structural units of ethylene glycol oxalate in PEOx, which is also the degree of polymerization of PEOx. p is a natural number and is greater than 400.

[0015] The PBOx structural formula is:

[0016]

[0017] Wherein, k is the number of structural units of butanediol oxalate in PBOx, and is also the degree of polymerization of PBOx. k is a natural number and is greater than 400.

[0018] Preferably, the terminal carboxyl removal agent is at least one of erythritol, sorbitol, inositol, mannitol, and glycerol; preferably, the terminal carboxyl removal agent is inositol.

[0019] Preferably, the antioxidant is at least one of trimethyl phosphate, triphenyl phosphate, triethyl phosphate, polyphosphoric acid, triethyl phosphoacetate, trimethyl phosphoacetate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-4-methylphenol, 4,4'-thiobis(6-tert-butyl-3-methylphenol), dilauryl thiodipropionate, and distearyl thiodipropionate; preferably, the antioxidant is 2,6-di-tert-butyl-4-methylphenol.

[0020] Preferably, the compatibilizer is an aliphatic anhydride compound, selected from at least one of acetic anhydride, ethylpropionic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, lauric anhydride, maleic anhydride, and itaconic anhydride; preferably, the compatibilizer is succinic anhydride.

[0021] Preferably, the high barrier performance PBAT composition comprises the following components in parts by mass:

[0022]

[0023] In a second aspect, the present invention provides a method for preparing a PBAT composition with high barrier properties, comprising the following steps:

[0024] According to the weight ratio, the dried PBAT, the dried polyoxalate, the end carboxyl removal agent, the antioxidant and the compatibilizer are put into a high-speed mixer in proportion, and after uniformly mixing in the high-speed mixer for at least 5 minutes, they are extruded into granules in a twin-screw extruder to obtain high-barrier performance PBAT composition pellets.

[0025] Preferably, the temperature of the twin-screw extruder from the feed port to the melt outlet is set to 160, 165, 170, 175 and 180° C. respectively.

[0026] Preferably, the PBAT and polyoxalate are dried by fully drying at 80° C. for not less than 12 hours.

[0027] Preferably, the dried high barrier performance PBAT composition pellets are put into a film blowing machine for film blowing processing to obtain a high barrier performance PBAT composition film.

[0028] Preferably, the temperatures from the feed port to the die port of the film blowing machine are set to 160, 165, 170, 175 and 180° C. respectively.

[0029] Preferably, the method for drying the high barrier performance PBAT composition pellets is: fully drying at 80° C. for not less than 12 hours.

[0030] A high-barrier-performance PBAT composition is used in fruit and food preservation bags or plastic wrap.

[0031] Beneficial effects:

[0032] ① The addition of the end carboxyl group removing agent can effectively increase the stability and compatibility of the material during the blending process, and improve the processability of the blended material into a film;

[0033] ②The compatibilizer can work synergistically with the end carboxyl removal agent to further improve the compatibility of the system;

[0034] ③ The small molecule additives used are all non-toxic substances, which avoids the toxic effects of the composite film after contact with fruits and other foods;

[0035] ④ The obtained PBAT / PEOx and PBAT / PBOx composite film materials have better barrier properties and mechanical properties than pure PBAT films, giving them broad market prospects in the field of freshness preservation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Comparative photos of strawberry preservation experiments using the high-barrier performance PBAT composition film prepared by the present invention and other types of fresh-keeping bags;

[0037] Figure 2Comparative photos of banana preservation experiments using the high-barrier performance PBAT composition film prepared by the present invention and other types of fresh-keeping bags. DETAILED DESCRIPTION

[0038] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0040] The preferred embodiments of the present invention will be described in detail below with reference to the examples. It should be understood that the following examples are provided for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0041] The mechanical properties described herein were tested using an Instron (5567A, USA) instrument under a load of 100 N. The testing protocol was performed in accordance with GB / T 1040.3-2006. Specimens were cut into dumbbell shapes, 115 mm long and 25 mm wide, with a 6 mm narrow neck. The tensile rate was 100 mm / min. Each sample was repeated at least five times.

[0042] The gas barrier test disclosed in the present invention is divided into a water vapor barrier test and an oxygen and carbon dioxide gas barrier test. The water vapor transmission rate (WVT) is measured using a water vapor transmission rate tester (GV-33-E, Labthink, China). At a temperature of 23°C and a relative humidity of 90%, a circular film with a diameter of 70 mm is tested in accordance with GB / T 1037-2021. Five parallel samples are collected in each group, and the average value is calculated. A gas transmission rate tester (VAC-V1, Labthink, China) is used to test the oxygen transmission rate (OT) and carbon dioxide transmission rate (CT). A circular film with a diameter of 50 mm is tested at 23°C in accordance with GB / T 1038-2000. Five parallel samples are collected in each group, and the average value is calculated.

[0043] The fruit preservation application disclosed in the present invention is specifically as follows: strawberries and bananas are wrapped with the composition film of the present invention, the composition film is prepared into an airtight packaging bag by a heat-sealing step, and the bag is stored at 20°C. Photos are taken at regular intervals to observe the degree of decay on the surface of the fruit.

[0044] Example 1

[0045] A high barrier performance PBAT composition, comprising the following components in parts by mass:

[0046]

[0047] Prepare according to the following steps:

[0048] (1) Dry PBAT and PEOx at 80°C for 12 hours;

[0049] (2) 100 parts of PBAT, 10 parts of PEOx, 1.5 parts of inositol, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol, and 0.4 parts of succinic anhydride were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set at 160, 165, 170, 175, and 180°C, respectively;

[0050] (3) The pellets obtained in step (2) were fully dried at 80° C. for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set to 160, 165, 170, 175, and 180° C., respectively. Thus, a high barrier performance PBAT composition film according to the present disclosure was obtained.

[0051] The PBAT composition film has a tensile strength of 43 MPa, an elongation at break of 1371%, and a water vapor permeability coefficient of 8.71×10 -14 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 4.25×10 -13 cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 2.15×10 -14 cm 3 cm / (cm 2 ·s·pa); the shelf life of strawberries is 8 days; the shelf life of bananas is 10 days.

[0052] Comparative Example 1 (Pure PBAT Film)

[0053] A high barrier performance PBAT composite film, wherein the composite film material comprises the following components in parts by mass:

[0054]

[0055]

[0056] Prepare according to the following steps:

[0057] (1) Dry PBAT at 80°C for 12 hours;

[0058] (2) 100 parts of PBAT, 1.5 parts of inositol, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol, and 0.4 parts of succinic anhydride were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set to 160, 165, 170, 175, and 180°C, respectively;

[0059] (3) The pellets obtained in step (2) were fully dried at 80°C for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set at 160, 165, 170, 175 and 180°C, respectively.

[0060] The PBAT composition film has a tensile strength of 28 MPa, an elongation at break of 1469%, and a water vapor permeability coefficient of 3.67×10 -13 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 9.88×10 -13 cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 7.35×10 -14 cm 3 cm / (cm 2 ·s·pa); strawberries can be kept fresh for 4 days; bananas can be kept fresh for 6 days.

[0061] Comparative Example 2 (without adding inositol and anhydride)

[0062] A high barrier performance PBAT composition, comprising the following components in parts by mass:

[0063]

[0064] Prepare according to the following steps:

[0065] (1) Dry PBAT at 80°C for 12 hours;

[0066] (2) 100 parts of PBAT, 10 parts of PEOx, and 0.2 parts of 2,6-di-tert-butyl-4-methylphenol were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set to 160, 165, 170, 175, and 180°C, respectively;

[0067] (3) The pellets obtained in step (2) were fully dried at 80°C for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set at 160, 165, 170, 175 and 180°C, respectively.

[0068] The PBAT composition film has a tensile strength of 22 MPa, an elongation at break of 1213%, and a water vapor permeability coefficient of 3.32×10 -13 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 9.12×10 -13 cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 7.44×10 -14 cm 3 cm / (cm 2 ·s·pa); strawberries can be kept fresh for 5 days; bananas can be kept fresh for 6 days.

[0069] Comparative Example 3 (Inositol is added but Succinic Anhydride is not added)

[0070] A high barrier performance PBAT composition, comprising the following components in parts by mass:

[0071]

[0072] Prepare according to the following steps:

[0073] (1) Dry PBAT at 80°C for 12 hours;

[0074] (2) 100 parts of PBAT, 10 parts of PEOx, 1.5 parts of inositol, and 0.2 parts of 2,6-di-tert-butyl-4-methylphenol were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set at 160, 165, 170, 175, and 180°C, respectively;

[0075] (3) The pellets obtained in step (2) were fully dried at 80°C for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set at 160, 165, 170, 175 and 180°C, respectively.

[0076] The PBAT composition film has a tensile strength of 29 MPa, an elongation at break of 1326%, and a water vapor permeability coefficient of 2.32×10 -13 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 3.57×10 -13 cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 6.11×10 -14 cm 3 cm / (cm 2·s·pa); strawberries can be kept fresh for 5 days; bananas can be kept fresh for 8 days.

[0077] Comparative Example 4 (without adding inositol and adding succinic anhydride)

[0078] A high barrier performance PBAT composite film, wherein the composite film material comprises the following components in parts by mass:

[0079]

[0080] Prepare according to the following steps:

[0081] (1) Dry PBAT at 80°C for 12 hours;

[0082] (2) 100 parts of PBAT, 10 parts of PEOx, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol, and 0.4 parts of succinic anhydride were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set at 160, 165, 170, 175, and 180°C, respectively;

[0083] (3) The pellets obtained in step (2) were fully dried at 80°C for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set at 160, 165, 170, 175 and 180°C, respectively.

[0084] The PBAT composition film has a tensile strength of 33 MPa, an elongation at break of 1302%, and a water vapor permeability coefficient of 2.27×10 -13 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 3.32×10 -13 cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 5.66×10 -14 cm 3 cm / (cm 2 ·s·pa); strawberries can be kept fresh for 5 days; bananas can be kept fresh for 8 days.

[0085] Comparative Example 5 (PEOx is replaced by polybutylene succinate (PBS))

[0086] A high barrier performance PBAT composition, comprising the following components in parts by mass:

[0087]

[0088] Prepare according to the following steps:

[0089] (1) Dry PBAT and PBS at 80°C for 12 hours;

[0090] (2) 100 parts of PBAT, 10 parts of PBS, 1.5 parts of inositol, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol, and 0.4 parts of succinic anhydride were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set to 160, 165, 170, 175, and 180°C, respectively;

[0091] (3) The pellets obtained in step (2) were fully dried at 80° C. for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set to 160, 165, 170, 175, and 180° C., respectively. Thus, a high barrier performance PBAT composition film according to the present disclosure was obtained.

[0092] The PBAT composition film has a tensile strength of 26 MPa, an elongation at break of 1311%, and a water vapor permeability coefficient of 4.55×10 -13 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 1.22×10 -12 cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 7.78×10 -14 cm 3 cm / (cm 2 ·s·pa); strawberries can be kept fresh for 4 days; bananas can be kept fresh for 6 days.

[0093] Example 2 (Increasing the content of PEOx)

[0094] A high barrier performance PBAT composition, comprising the following components in parts by mass:

[0095]

[0096] Prepare according to the following steps:

[0097] (1) Dry PBAT and PEOx at 80°C for 12 hours;

[0098] (2) 100 parts of PBAT, 15 parts of PEOx, 1.5 parts of inositol, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol, and 0.4 parts of succinic anhydride were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set at 160, 165, 170, 175, and 180°C, respectively;

[0099] (3) The pellets obtained in step (2) were fully dried at 80°C for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set at 160, 165, 170, 175 and 180°C, respectively.

[0100] The PBAT composition film has a tensile strength of 45 MPa, an elongation at break of 1218%, and a water vapor permeability coefficient of 7.12×10 -14 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 3.77×10 -13 cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 2.04×10 -14 cm 3 cm / (cm 2 ·s·pa); the shelf life of strawberries is 8 days; the shelf life of bananas is 10 days.

[0101] Example 3 (PBAT / PBOx composition)

[0102] A high barrier performance PBAT composition, comprising the following components in parts by mass:

[0103]

[0104] Prepare according to the following steps:

[0105] (1) Dry PBAT and PBOx at 80°C for 12 hours;

[0106] (2) 100 parts of PBAT, 10 parts of PBOx, 1.5 parts of inositol, 0.2 parts of 2,6-di-tert-butyl-4-methylphenol, and 0.4 parts of succinic anhydride were uniformly mixed in a high-speed mixer for 5 minutes and then extruded into pellets in a twin-screw extruder. The temperatures from the feed port to the melt outlet were set to 160, 165, 170, 175, and 180°C, respectively;

[0107] (3) The pellets obtained in step (2) were fully dried at 80° C. for 12 hours and then subjected to film blowing in a film blowing machine. The temperatures from the feed port to the die were set to 160, 165, 170, 175, and 180° C., respectively. Thus, a high barrier performance PBAT composition film according to the present disclosure was obtained.

[0108] The PBAT composition film has a tensile strength of 40 MPa, an elongation at break of 1446%, and a water vapor permeability coefficient of 9.57×10 -14 g·cm / (cm 2 ·s·pa); the carbon dioxide permeability coefficient is 1.05×10 -13cm 3 cm / (cm 2 ·s·pa); oxygen permeability coefficient is 1.11×10 -14 cm 3 cm / (cm 2 ·s·pa); the shelf life of strawberries is 8 days; the shelf life of bananas is 10 days.

[0109] As can be seen from Example 1 and Comparative Example 1, the pure PBAT film has low mechanical strength and no significant preservation effect on fruit. However, the PBAT composite film can extend the shelf life of strawberries and bananas to 8 days and 10 days, respectively. This shows that the addition of PEOx significantly improves the fruit preservation performance of the composite film.

[0110] As can be seen from Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, the mechanical strength of pure PBAT films is low. The addition of inositol and succinic anhydride significantly improves their mechanical strength. Furthermore, the effect of adding either inositol or succinic anhydride alone is not as significant as the mechanical strength improvement achieved by adding both simultaneously. This suggests that the system is more compatible after adding both, and they can act synergistically. Furthermore, their simultaneous addition significantly increases the shelf life of fruit.

[0111] It can be seen from Example 3 that after adding PBOx to replace PEOx, the composite film can also achieve the same technical effect as PBAT / PEOx, significantly improving the shelf life of fruits.

[0112] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A high barrier performance PBAT composition, characterized in that: Calculated by mass, it contains the following components: The PBAT is polybutylene terephthalate adipate, and its structural formula is: Wherein, x is the number of butylene terephthalate structural units in PBAT, y is the number of butylene adipate structural units in PBAT, and n is the degree of polymerization of PBAT. x, y, and n are all natural numbers, 150<n<200; The polyoxalate is selected from at least one of polyethylene oxalate (PEOx) and polybutylene oxalate (PBOx); The terminal carboxyl group removing agent is at least one of erythritol, sorbitol, inositol, mannitol, and glycerol; The compatibilizer is selected from at least one of acetic anhydride, ethylpropionic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, lauric anhydride, maleic anhydride and itaconic anhydride.

2. The high barrier performance PBAT composition according to claim 1, characterized in that: The molar ratio of x to y is 6:(4-9).

3. The high barrier performance PBAT composition according to claim 2, characterized in that: The molar ratio of x to y is 45:55, 47:53 or 50:

50.

4. The high barrier performance PBAT composition according to claim 1, characterized in that: The antioxidant is selected from at least one of trimethyl phosphate, triphenyl phosphate, triethyl phosphate, polyphosphoric acid, triethyl phosphoacetate, trimethyl phosphoacetate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-4-methylphenol, 4,4'-thiobis(6-tert-butyl-3-methylphenol), dilauryl thiodipropionate, and distearyl thiodipropionate.

5. The high barrier performance PBAT composition according to claim 1, characterized in that: Calculated by mass, it contains the following components:

6. A method for preparing a high barrier performance PBAT composition according to any one of claims 1 to 5, characterized in that: The steps include: The measured dried PBAT and polyoxalate, together with the end carboxyl removal agent, antioxidant and compatibilizer, are put into a high-speed mixer in parts by mass. After uniform mixing in the high-speed mixer, they are extruded and granulated in a twin-screw extruder to obtain high-barrier performance PBAT composition pellets.

7. The preparation method according to claim 6, characterized in that The dried high-barrier performance PBAT composition pellets are put into a film blowing machine for film blowing processing to obtain a high-barrier performance PBAT composition film.

8. The preparation method according to claim 6, characterized in that The temperatures from the screw extruder feed port to the melt outlet were set to 160, 165, 170, 175 and 180° C., respectively.

9. The preparation method according to claim 7, characterized in that The temperatures of the film blowing machine from the feed port to the die port were set to 160, 165, 170, 175 and 180° C., respectively.

10. Use of the high barrier performance PBAT composition according to any one of claims 1 to 5 in fruit or food preservation bags or plastic wrap.

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