High-barrier biodegradable film with continuous layered structure and method for preparing the same

Abstract

The application provides a high-barrier biodegradable film with a continuous layered structure and a preparation method thereof. The preparation method comprises the following steps: first melt blending of a multifunctional epoxy chain extender, a first part of polybutylene adipate terephthalate and polybutylene succinate to obtain a master batch; second melt blending of the master batch, optionally a second part of polybutylene adipate terephthalate and 3-hydroxybutyric acid-3-hydroxyvaleric acid copolymer to obtain a blend; and film blowing of the blend to obtain the film. The preparation method can construct a continuous layered barrier structure in a single-layer film at a relatively low content of high-barrier polyester to achieve the purpose of high-efficiency barrier.

Description

TECHNICAL FIELD

[0001] The present application relates to a high-barrier biodegradable film with a continuous layered structure and a preparation method thereof, and belongs to the field of biodegradable films. BACKGROUND

[0002] Biodegradable films have environmental protection properties. Such films mainly use degradable materials such as polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), and polyhydroxyalkanoate (PHA) as the main body resin to provide flexibility to the biodegradable film, and can be converted into water, carbon dioxide and biomass in the natural environment through microbial action.

[0003] At present, biodegradable films have been widely used in food packaging, agricultural mulching film, medical supplies and daily consumer goods fields, and have both functionality and environmental friendliness, becoming an important direction of green material development. Due to the characteristics of the use scene, many fields have high requirements for the barrier properties of biodegradable films.

[0004] PBAT is a biodegradable resin with high flexibility, which is often used as a base resin for biodegradable films to provide flexibility. However, PBAT has poor water vapor barrier properties. At present, multi-layer composite films are often used to improve the barrier properties of biodegradable films. However, the multi-layer film technology has high requirements for the processing temperature matching and viscosity of the base resin, and the production process is relatively complex, and the equipment cost is relatively high.

[0005] Therefore, by melt blending technology, a layered structure can also be formed in PBAT to improve the barrier properties. And the blowing process of single-layer film is relatively simple, and the requirement for equipment is low. However, the layered structure can only fully play its barrier properties when it has high continuity. Generally speaking, when the mass content of polyester as a barrier phase is more than 50wt%, a bicontinuous phase can be formed with PBAT, thereby forming a continuous layered structure in the subsequent film blowing process. However, high-barrier biodegradable polyesters generally have high rigidity, such as PLA, PHBV and PGA, and excessive addition will cause the flexibility of the film to drop sharply.

[0006] Therefore, it is still difficult in technology to construct a continuous layered barrier structure in a single-layer film with a relatively low content of high-barrier polyester to achieve high-efficiency barrier. Therefore, it is necessary to provide a new preparation method of biodegradable film to improve the above problems. SUMMARY

[0007] In order to solve the above technical problems, the present application aims to provide a high-barrier biodegradable film with a continuous layered structure and a preparation method thereof.

[0008] To achieve the above-mentioned purposes, the present application provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, comprising the following steps: first melt blending a multi-functional epoxy chain extender, a first part of polybutylene adipate terephthalate (PBAT) and polybutylene succinate (PBS) to obtain a masterbatch; second melt blending the masterbatch, optionally a second part of polybutylene adipate terephthalate (PBAT) and 3-hydroxybutyric acid-3-hydroxyvaleric acid copolymer (PHBV) to obtain a blend; and blowing the blend to obtain a film. The weight ratio of the masterbatch, the second part of polybutylene adipate terephthalate (PBAT) and 3-hydroxybutyric acid-3-hydroxyvaleric acid copolymer (PHBV) is 10-70:0-70:30, preferably 10-30:40-60:30; the die temperature of the film blowing is 160-180℃; and the draw ratio of the film blowing is 5-16.

[0009] In the present application, the multi-functional epoxy chain extender is first melt blended with PBAT and PBS to obtain a PBAT-b-PBS masterbatch, and then the PBAT-b-PBS masterbatch is second melt blended with PBAT and PHBV to obtain a blend. The PBAT-b-PBS masterbatch has a regulating effect on the interfacial tension among PBAT, PBS and PHBV in the blend. Based on this, a continuous layered barrier structure with high continuity (the "continuous layered barrier structure" refers to a continuous layered structure of PBS and PHBV formed in PBAT under the influence of interfacial tension) can be constructed in a single-layer PBAT film under lower PHBV content and milder process conditions, thereby achieving the beneficial effect of greatly improving the water vapor barrier performance of the film, and avoiding the disadvantage of sharp decline in film flexibility caused by excessive addition of PHBV.

[0010] In some optional embodiments, the melt index of PBAT is 3-5 g / 10 min (test conditions: 190℃ / 2.16 kg). The melt index of PBS is 3-6 g / 10 min (test conditions: 190℃ / 2.16 kg). The melt index of PHBV is 5-10 g / 10 min (test conditions: 190℃ / 2.16 kg).

[0011] In a preferred embodiment, the weight ratio of the multi-functional epoxy chain extender, the first part of polybutylene adipate terephthalate, and polybutylene succinate is 0.1-1:50:50.

[0012] Further, the processing temperature of the first melt blending is 180-195°C, preferably 190-195°C. The first melt blending is performed in a twin-screw extruder at a rotation speed of 80-120 r / min.

[0013] Further, the multi-functional epoxy chain extender is selected from one or a combination of two or more of styrene acrylic glycidyl ester (e.g. ST-CE37B, ADR4400, KL-E4370), isocyanuric acid triglycidyl ester (e.g. TGIC) and tetrahydrophthalic acid diglycidyl ester (711), preferably styrene acrylic glycidyl ester.

[0014] Further, the processing temperature of the second melt blending is 180-195°C.

[0015] Further, the second melt blending is performed in a twin-screw extruder at a rotation speed of 80-120 r / min.

[0016] In a preferred embodiment, the film blowing comprises: first melting the blend in a single-screw extruder at a temperature of 180-195°C to obtain a blend melt, then reducing the temperature of the blend melt to 160-180°C to make the blend melt have a suitable film blowing viscosity, and then blowing into a film.

[0017] Further, the blow-up ratio of the film blowing is 2-5.

[0018] The application also provides a high-barrier biodegradable film with a continuous layered structure, which is prepared by the aforementioned preparation method. Preferably, the thickness of the film is 10-100 μm. Based on the foregoing reasons, the high-barrier biodegradable film with a continuous layered structure obtained by the application not only has very excellent water vapor barrier properties, but also has good flexibility. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A schematic diagram showing the formation of a continuous layered structure in an embodiment of the application is shown;

[0020] Figure 2 A scanning electron microscope image of a PBAT / PHBV blend in Comparative Example 2 of the application is shown;

[0021] Figure 3 A scanning electron microscope image of a PBAT / PHBV / PBAT-b-PBS blend in Example 1 of the application is shown;

[0022] Figure 4 A scanning electron microscope image of a PBAT / PHBV / PBAT-b-PBS blend in Example 2 of the application is shown;

[0023] Figure 5 A scanning electron microscope image of the PBAT / PHBV / PBAT-b-PBS blend in the embodiment 3 of the present application is shown.

[0024] Figure 6 A scanning electron microscope image of the PBAT / PHBV / PBAT-b-PBS blend in the embodiment 4 of the present application is shown. DETAILED DESCRIPTION

[0025] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but it should not be understood as a limitation on the implementable scope of the present application.

[0026] All numerical designations (such as temperature, time, concentration, weight, etc., including ranges for each of them) herein can generally be approximations. Unless otherwise stated, the numerical designations are to be understood, to be approximations. All numerical designations can be variable depending on the desired properties of the final product to be formed. All numerical designations are to be understood to be preceded by the word "about" even if the term does not expressly appear. The numerical designations can be varied by + or - 0.1 or 1.0 as appropriate. Figure 1 A schematic diagram showing the formation of a continuous layered structure in one embodiment of the present application is shown.

[0027] Embodiment 1

[0028] The present embodiment provides a method for preparing a high-barrier biodegradable film having a continuous layered structure, which comprises the following steps:

[0029] 1) ST-CE37B, PBAT and PBS were melt-blended in a twin-screw extruder at a rotation speed of 100 r / min at 195℃ to obtain a PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0030] 2) PBAT, PHBV and the PBAT-b-PBS masterbatch were melt-blended in a twin-screw extruder at a rotation speed of 100 r / min at 180℃ to obtain a PBAT / PHBV / PBAT-b-PBS blend granules, and the weight ratio of PBAT, PHBV and the PBAT-b-PBS masterbatch was 50:30:20.

[0031] 3) The PBAT / PHBV / PBAT-b-PBS blend granules were subjected to sufficient melting in a single-screw extruder at 180℃ to obtain a blend melt, and then the blend melt was lowered to 170℃, and a film was blown at a draw ratio of 6.5, a blow-up ratio of 4.5 and a film blowing die temperature of 170℃ to obtain a high-barrier biodegradable film having a continuous layered structure.

[0032] Embodiment 2

[0033] The embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0034] 1) In a double screw extruder, ST-CE37B, PBAT and PBS are melt blended at 195 DEG C at a rotating speed of 100 r / min to obtain PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0035] 2) In a double screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch are melt blended at 180 DEG C at a rotating speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch is 30:30:40.

[0036] 3) In a single screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles are sufficiently melt blended at 180 DEG C to obtain a blend melt, then the blend melt is lowered to 170 DEG C, and a film is blown at a draw ratio of 6.5, a blow-up ratio of 4.5 and a film blowing die temperature of 170 DEG C to obtain a high-barrier biodegradable film with a continuous layered structure.

[0037] Embodiment 3

[0038] The embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0039] 1) In a double screw extruder, ST-CE37B, PBAT and PBS are melt blended at 195 DEG C at a rotating speed of 100 r / min to obtain PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0040] 2) In a double screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch are melt blended at 180 DEG C at a rotating speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch is 30:30:40.

[0041] 3) In a single screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles are sufficiently melt blended at 180 DEG C to obtain a blend melt, then the blend melt is lowered to 170 DEG C, and a film is blown at a draw ratio of 6.5, a blow-up ratio of 4.5 and a film blowing die temperature of 170 DEG C to obtain a high-barrier biodegradable film with a continuous layered structure.

[0042] Example 4

[0043] This embodiment provides a method for preparing a high-barrier biodegradable film with a continuous layered structure, which includes the following steps:

[0044] 1) In a twin-screw extruder, ST-CE37B, PBAT and PBS are melt-blended at 195°C at a speed of 100 r / min to obtain PBAT-b-PBS masterbatch. The weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0045] 2) In a twin-screw extruder, PHBV and PBAT-b-PBS masterbatch are melt-blended at 180°C with a rotation speed of 100 r / min to obtain PHBV / PBAT-b-PBS blend particles. The weight ratio of PHBV to PBAT-b-PBS masterbatch is 30:70.

[0046] 3) In a single-screw extruder, the PHBV / PBAT-b-PBS blend particles are fully melted at 180°C to obtain a blend melt. The blend melt is then cooled to 170°C and blown into a film with a draw ratio of 6.5, a blow-up ratio of 4.5, and a blown film head temperature of 170°C to obtain a high-barrier biodegradable film with a continuous layered structure.

[0047] Comparative Example 1

[0048] This comparative example provides a method for preparing a biodegradable film, which includes the following steps:

[0049] 1) In a twin-screw extruder, PBAT is melt-extruded at 180°C at a speed of 100 r / min to obtain PBAT granules.

[0050] 2) In a single-screw extruder, PBAT particles are fully melted at 180°C to obtain a blend melt. The blend melt is then cooled to 170°C and blown into a film with a draw ratio of 6.5, a blow-up ratio of 4.5, and a blown film head temperature of 170°C to obtain a biodegradable film.

[0051] Comparative Example 2

[0052] This comparative example provides a method for preparing a biodegradable film, which includes the following steps:

[0053] 1) In a twin-screw extruder, PBAT and PHBV are melt-blended at 180°C at a rotation speed of 100 r / min to obtain PBAT / PHBV blend particles with a weight ratio of PBAT to PHBV of 70:30.

[0054] 2) In a single screw extruder, the PBAT / PHBV blend particles were sufficiently melted at 180℃ to obtain a blend melt, then the blend melt was lowered to 170℃, blown into a film with a draw ratio of 6.5, a blow-up ratio of 4.5, and a film blowing die temperature of 170℃, to obtain a biodegradable film.

[0055] Comparative Example 3

[0056] The present comparative example provides a method for preparing a biodegradable film, comprising the following steps:

[0057] 1) In a twin screw extruder, PBAT and PHBV were melt blended at 180℃ at a rotation speed of 100r / min to obtain PBAT / PHBV blend particles, the weight ratio of PBAT and PHBV being 50:50.

[0058] 2) In a single screw extruder, the PBAT / PHBV blend particles were sufficiently melted at 180℃ to obtain a blend melt, then the blend melt was lowered to 170℃, blown into a film with a draw ratio of 6.5, a blow-up ratio of 4.5, and a film blowing die temperature of 170℃, to obtain a high-barrier biodegradable film with a continuous layered structure.

[0059] Table 1 shows the raw material formula (by weight fraction) of the blend particles in Examples 1-4 and Comparative Examples 1-3.

[0060] Table 1

[0061] PBAT (parts) PBHV (parts) PBAT-b-PBS (parts) Example 1 50 30 20 Example 2 30 30 40 Example 3 10 30 60 Example 4 0 30 70 Comparative Example 1 100 0 0 Comparative Example 2 70 30 0 Comparative Example 3 50 50 0

[0062] Figure 2 The scanning electron microscope image of the PBAT / PHBV blend particles in Comparative Example 2 of the present application is shown, from which Figure 2 It can be found that when the PBAT-b-PBS masterbatch is 0 parts, the PHBV exists in the form of island structure with a size of 3-10μm.

[0063] Figure 3 The scanning electron microscope image of the PHBV / PBAT-b-PBS blend particles in Example 1 of the present application is shown, from which Figure 3 It can be found that as the content of the PBAT-b-PBS masterbatch increases to 20 parts by weight, the weight ratio of PBAT:PHBV:PBS in the blend being 60:30:10, the size of the PHBV island structure increases to 40-60μm, and the PBS forms a shell structure distributed on the outer layer of the PHBV island structure, forming a core-shell structure.

[0064] Figure 4 The scanning electron microscope image of the PHBV / PBAT-b-PBS blend particles in Example 2 of the present application is shown, from which Figure 5The scanning electron microscope images of PHBV / PBAT-b-PBS blend particles in the embodiment 3 of the present application are shown, from which Figure 4 and Figure 5 It can be found that as the PBAT-b-PBS masterbatch content increases to 40-60 parts, at which the weight ratio of PBAT:PHBV:PBS in the blend reaches 40-50:30:20-30, PHBV and PBS begin to form a continuous layered structure.

[0065] Figure 6 The scanning electron microscope images of PHBV / PBAT-b-PBS blend particles in the embodiment 4 of the present application are shown, from which Figure 6 It can be found that as the PBAT-b-PBS masterbatch content further increases to 70 parts, at which the weight ratio of PBAT:PHBV:PBS in the blend is 35:30:35, PBS and PBAT achieve phase inversion, PBS becomes the continuous phase, and PBAT and PHBV exist in the form of islands in the PBS continuous phase.

[0066] It can be seen that the introduction of PBAT-b-PBS masterbatch can convert PHBV from island structure to continuous structure at a constant and low PHBV content, and further form a high-continuous layered structure in the subsequent film blowing process.

[0067] Table 2 shows the water vapor transmission performance and fracture toughness test results of the films prepared in the embodiments 1-4 and the comparative examples 1-3.

[0068] Table 2

[0069]

[0070] In the comparative example 1, the water vapor transmission of the PBAT film is 320.3 g / m 2 ·24h, the water vapor transmission coefficient is 5.91x10 -13 g·cm / m 2 ·s·Pa, and the water vapor transmission performance is poor.

[0071] In the comparative example 2, the water vapor transmission of the PBAT / PHBV (70:30) film is 68.1 g / m 2 ·24h, the water vapor transmission coefficient is 1.24x10 -13 g·cm / m 2 ·s·Pa, and the water vapor transmission performance is poor.

[0072] In the comparative example 3, the water vapor transmission of the PBAT / PHBV (50:50) film is significantly reduced to 34.1 g / m 2 ·24h, the water vapor transmission coefficient is 0.66x10 -13g·cm / m 2 ·s·Pa, but the film elongation at break is only 53.8%, and the material fracture toughness drops sharply.

[0073] In Example 1, when the content of PBAT-g-PBS masterbatch is 20 parts, the water vapor transmission rate of PBAT / PHBV / PBAT-g-PBS film is reduced to 54.8 g / m 2 ·24h, the water vapor transmission coefficient is 0.99 x 10 -13 g·cm / m 2 ·s·Pa, the water vapor transmission performance is improved, and the film elongation at break is 775.3%, and the material still has good fracture toughness.

[0074] In Example 2, when the content of PBAT-g-PBS masterbatch is 40 parts, the water vapor transmission rate of PBAT / PHBV / PBAT-g-PBS film is significantly reduced to 44.3 g / m 2 ·24h, the water vapor transmission coefficient is 0.81 x 10 -13 g·cm / m 2 ·s·Pa, the water vapor transmission performance is significantly improved, and the film elongation at break is 645.6%, and the material still has good fracture toughness.

[0075] In Example 3, when the content of PBAT-g-PBS masterbatch is 60 parts, the water vapor transmission rate of PBAT / PHBV / PBAT-g-PBS film is further reduced to 43.1 g / m 2 ·24h, the water vapor transmission coefficient is 0.79 x 10 -13 g·cm / m 2 ·s·Pa, the water vapor transmission performance is further improved, and the film elongation at break is 521.5%, and the material still has good fracture toughness.

[0076] In Example 4, when the content of PBAT-g-PBS masterbatch is 70 parts, the water vapor transmission rate of PBAT / PHBV / PBAT-g-PBS film is further reduced to 41.4 g / m 2 ·24h, the water vapor transmission coefficient is 0.74 x 10 -13 g·cm / m 2 ·s·Pa, the water vapor transmission performance is further improved, but the improvement is not large, at the same time, the film elongation at break is 353.8%, and the material fracture toughness decreases.

[0077] It can be seen that the excessive introduction of PHBV can improve the barrier property of the film, but can significantly reduce the fracture toughness of the film (for example, Comparative Example 3). The PBAT-b-PBS master batch formed by the end group reaction in the present application can adjust the phase structure of the PBAT / PHBV system, so that the PHBV content of 30wt% can form a continuous barrier layer in the film, improve the water vapor barrier property of the biodegradable film, and at the same time, the material still maintains good fracture toughness.

[0078] Example 5

[0079] The present embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0080] 1) In a twin-screw extruder, melt blend ST-CE37B, PBAT and PBS at 195℃ with a rotation speed of 100r / min to obtain a PBAT-b-PBS master batch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0081] 2) In a twin-screw extruder, melt blend PBAT, PHBV and PBAT-b-PBS master batch at 180℃ with a rotation speed of 100r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS master batch is 30:30:40.

[0082] 3) In a single-screw extruder, melt PBAT / PHBV / PBAT-b-PBS blend particles at 180℃ to obtain a blend melt, then reduce the blend melt to 160℃, and blow it into a film with a draw ratio of 6.5, a blow ratio of 4.5 and a film blowing head temperature of 160℃ to obtain a high-barrier biodegradable film with a continuous layered structure.

[0083] Example 6

[0084] The present embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0085] 1) In a twin-screw extruder, melt blend ST-CE37B, PBAT and PBS at 195℃ with a rotation speed of 100r / min to obtain a PBAT-b-PBS master batch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0086] 2) In a twin-screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended at 180℃ at a rotation speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0087] 3) In a single-screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles were sufficiently melted at 180℃ to obtain a blend melt, and then the blend melt was blown into a film at a draw ratio of 6.5, a blow-up ratio of 4.5 and a film blowing die temperature of 180℃ to obtain a high-barrier biodegradable film with a continuous layered structure.

[0088] Comparative Example 4

[0089] The present comparative example provides a method for preparing a film, comprising the following steps:

[0090] 1) In a twin-screw extruder, ST-CE37B, PBAT and PBS were melt blended at 195℃ at a rotation speed of 100 r / min to obtain a PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0091] 2) In a twin-screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended at 180℃ at a rotation speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0092] 3) In a single-screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles were sufficiently melted at 180℃ to obtain a blend melt, and then the blend melt was blown into a film at a draw ratio of 6.5, a blow-up ratio of 4.5 and a film blowing die temperature of 150℃, and it was found that it could not be formed.

[0093] Comparative Example 5

[0094] The present comparative example provides a method for preparing a film, comprising the following steps:

[0095] 1) In a twin-screw extruder, ST-CE37B, PBAT and PBS were melt blended at 195℃ at a rotation speed of 100 r / min to obtain a PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0096] 2) In a twin-screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended at 180 °C at a rotation speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0097] 3) In a single-screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles were sufficiently melted at 180 °C to obtain a blend melt, and then blown into a film at a draw ratio of 6.5, a blow-up ratio of 4.5 and a film blowing die temperature of 190 °C to obtain a film, but gourd-shaped film bubbles appeared.

[0098] Table 3 shows the water vapor transmission performance and the film bubble forming test results of the films prepared in Examples 5-6 and Comparative Examples 4-5.

[0099] Table 3

[0100]

[0101] Example 7

[0102] The present embodiment provides a method for preparing a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0103] 1) In a twin-screw extruder, ST-CE37B, PBAT and PBS were melt blended at 195 °C at a rotation speed of 100 r / min to obtain a PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0104] 2) In a twin-screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended at 180 °C at a rotation speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0105] 3) In a single-screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles were sufficiently melted at 180 °C to obtain a blend melt, and then the blend melt was lowered to 170 °C, blown into a film at a draw ratio of 6.5, a blow-up ratio of 2 and a film blowing die temperature of 170 °C to obtain a high-barrier biodegradable film with a continuous layered structure.

[0106] Example 8

[0107] The embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0108] 1) In a double screw extruder, ST-CE37B, PBAT and PBS are melt blended at 195 DEG C at a rotating speed of 100 r / min to obtain PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0109] 2) In a double screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch are melt blended at 180 DEG C at a rotating speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch is 30:30:40.

[0110] 3) In a single screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles are sufficiently melt blended at 180 DEG C to obtain a blend melt, then the blend melt is lowered to 170 DEG C, and a film is blown at a draw ratio of 6.5, a blow-up ratio of 3 and a film blowing die temperature of 170 DEG C to obtain a high-barrier biodegradable film with a continuous layered structure.

[0111] Example 9

[0112] The embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0113] 1) In a double screw extruder, ST-CE37B, PBAT and PBS are melt blended at 195 DEG C at a rotating speed of 100 r / min to obtain PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0114] 2) In a double screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch are melt blended at 180 DEG C at a rotating speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch is 30:30:40.

[0115] 3) In a single screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles are sufficiently melt blended at 180 DEG C to obtain a blend melt, then the blend melt is lowered to 170 DEG C, and a film is blown at a draw ratio of 6.5, a blow-up ratio of 4 and a film blowing die temperature of 170 DEG C to obtain a high-barrier biodegradable film with a continuous layered structure.

[0116] Example 10

[0117] The embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0118] 1) ST-CE37B, PBAT and PBS are melt-blended in a double screw extruder at a rotating speed of 100 r / min at 195 DEG C to obtain PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0119] 2) PBAT, PHBV and PBAT-b-PBS masterbatch are melt-blended in a double screw extruder at a rotating speed of 100 r / min at 180 DEG C to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch is 30:30:40.

[0120] 3) PBAT / PHBV / PBAT-b-PBS blend particles are sufficiently melted in a single screw extruder at 180 DEG C to obtain a blend melt, then the blend melt is lowered to 170 DEG C, and a film is blown by a film blowing machine head temperature of 170 DEG C at a draw ratio of 6.5 and a blow ratio of 5 to obtain a high-barrier biodegradable film with a continuous layered structure.

[0121] Example 11

[0122] The embodiment provides a preparation method of a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0123] 1) ST-CE37B, PBAT and PBS are melt-blended in a double screw extruder at a rotating speed of 100 r / min at 195 DEG C to obtain PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B is 50:50:0.5.

[0124] 2) PBAT, PHBV and PBAT-b-PBS masterbatch are melt-blended in a double screw extruder at a rotating speed of 100 r / min at 180 DEG C to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch is 30:30:40.

[0125] 3) In a single screw extruder, the PBAT / PHBV / PBAT-b-PBS blend particles were fully melted at 180℃ to obtain a blend melt, and then the blend melt was lowered to 170℃, blown into a film at a draw ratio of 5, a blow-up ratio of 2, and a film blowing die temperature of 170℃, to obtain a high-barrier biodegradable film with a continuous layered structure.

[0126] Example 12

[0127] The present embodiment provides a method for preparing a high-barrier biodegradable film with a continuous layered structure, comprising the following steps:

[0128] 1) In a twin-screw extruder, ST-CE37B, PBAT and PBS were melt blended at 195℃ at a rotation speed of 100 r / min to obtain a PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0129] 2) In a twin-screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended at 180℃ at a rotation speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0130] 3) In a single screw extruder, the PBAT / PHBV / PBAT-b-PBS blend particles were fully melted at 180℃ to obtain a blend melt, and then the blend melt was lowered to 170℃, blown into a film at a draw ratio of 9, a blow-up ratio of 2, and a film blowing die temperature of 170℃, to obtain a high-barrier biodegradable film with a continuous layered structure.

[0131] Example 13

[0132] The present embodiment provides a method for preparing a high-barrier biodegradable film with a continuous layered structure, comprising the following steps:

[0133] 1) In a twin-screw extruder, ST-CE37B, PBAT and PBS were melt blended at 195℃ at a rotation speed of 100 r / min to obtain a PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0134] 2) In a twin-screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended at 180℃ at a rotation speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0135] 3) In a single-screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles were fully melted at 180℃ to obtain a blend melt, and then the blend melt was lowered to 170℃, blown into a film at a draw ratio of 13, a blow-up ratio of 2 and a film blowing die temperature of 170℃ to obtain a high-barrier biodegradable film with a continuous layered structure.

[0136] Example 14

[0137] The present example provides a method for preparing a high-barrier biodegradable film with a continuous layered structure, which comprises the following steps:

[0138] 1) In a twin-screw extruder, ST-CE37B, PBAT and PBS were melt blended at 195℃ at a rotation speed of 100 r / min to obtain a PBAT-b-PBS masterbatch, and the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0139] 2) In a twin-screw extruder, PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended at 180℃ at a rotation speed of 100 r / min to obtain PBAT / PHBV / PBAT-b-PBS blend particles, and the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0140] 3) In a single-screw extruder, PBAT / PHBV / PBAT-b-PBS blend particles were fully melted at 180℃ to obtain a blend melt, and then the blend melt was lowered to 170℃, blown into a film at a draw ratio of 16, a blow-up ratio of 2 and a film blowing die temperature of 170℃ to obtain a high-barrier biodegradable film with a continuous layered structure.

[0141] Comparative Example 6

[0142] The present comparative example provides a method for preparing a film, which comprises the following steps:

[0143] 1) ST-CE37B, PBAT and PBS were melt blended in a twin-screw extruder at 100 r / min at 195℃ to obtain PBAT-b-PBS masterbatch, the weight ratio of PBAT, PBS and ST-CE37B was 50:50:0.5.

[0144] 2) PBAT, PHBV and PBAT-b-PBS masterbatch were melt blended in a twin-screw extruder at 100 r / min at 180℃ to obtain PBAT / PHBV / PBAT-b-PBS blend particles, the weight ratio of PBAT, PHBV and PBAT-b-PBS masterbatch was 30:30:40.

[0145] 3) PBAT / PHBV / PBAT-b-PBS blend particles were sufficiently melted in a single-screw extruder at 180℃ to obtain a blend melt, then the blend melt was blown at a draw ratio of 19, a blow-up ratio of 2 and a film blowing die temperature of 170℃, the film could not be effectively cooled and the roller was seriously stuck due to too fast pulling speed.

[0146] Table 4 shows the water vapor transmission performance test results of the films prepared in Examples 7-14 and Comparative Example 6.

[0147] Table 4

[0148]

[0149] In Examples 7-10, after the PBS-b-PHBV masterbatch was added to form a continuous layered structure in PBAT / PHBV, the film could have good water vapor barrier performance even in the case of a small blow-up ratio. With the increase of the blow-up ratio, all the polymer films had good water vapor barrier performance, and the water vapor barrier performance changed little. In Examples 11-14, after the PBS-b-PHBV masterbatch was added to form a continuous layered structure in PBAT / PHBV, the film could have good water vapor barrier performance even in the case of a small blow-up ratio and a large draw ratio. With the increase of the draw ratio, all the polymer films had good water vapor barrier performance, and the water vapor barrier performance changed little. It is shown that after the continuous barrier layer is formed using the method, the water vapor barrier performance of the film depends less on the draw ratio and the blow-up ratio, and a high-toughness biodegradable film with better barrier performance can be prepared under milder conditions. However, the draw ratio should not be too large, otherwise the film cannot be effectively cooled and the roller is seriously stuck, and the film cannot be formed.

Claims

1. A method for preparing a high-barrier biodegradable film with a continuous layered structure, wherein, Includes the following steps: A multifunctional epoxy chain extender, a first portion of polybutylene adipate terephthalate, and polybutylene succinate are melt-blended to obtain a masterbatch. The masterbatch, the second part of polybutylene terephthalate, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) are subjected to a second melt blending to obtain a blend. The blend is blown into a film to obtain a thin film; The weight ratio of the masterbatch, the second part polybutylene terephthalate, and the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is 10~70:0~70:

30. The temperature of the blown film head is 160~180℃; The draw ratio of the blown film is 5~16.

2. The preparation method according to claim 1, wherein, The weight ratio of the masterbatch, the second part polybutylene adipate terephthalate, and the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is 10~30:40~60:

30.

3. The preparation method according to claim 1, wherein, The weight ratio of the multifunctional epoxy chain extender, the first portion of polybutylene adipate terephthalate, and the butylene succinate is 0.1~1:50:

50.

4. The preparation method according to claim 1, wherein, The processing temperature of the first melt blend is 180~195℃.

5. The preparation method according to claim 1, wherein, The processing temperature for the second melt blend is 180~195℃.

6. The preparation method according to claim 1, wherein, The blown film has a blow-up ratio of 2 to 5.

7. The preparation method according to claim 1, wherein, The multifunctional epoxy chain extender is selected from one or more of glycidyl styrene acrylate, triglycidyl isocyanurate, and diglycidyl tetrahydrophthalate.

8. The preparation method according to claim 7, wherein, The multifunctional epoxy chain extender is glycidyl styrene acrylate.

9. The preparation method according to claim 1, wherein, The blown film process includes: first melting the blend at a temperature of 180~195°C to obtain a blend melt, then lowering the temperature of the blend melt to 160~180°C, and then blowing the blend melt into a film.

10. A high-barrier biodegradable film having a continuous layered structure, wherein, It is prepared by the preparation method according to any one of claims 1-9.

11. The high-barrier biodegradable film with a continuous layered structure according to claim 10, wherein, The thickness of the film is 10~100μm.

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