High-barrier film with staggered ordered micro / nano barrier layer structure and preparation method thereof

Abstract

The application provides a high-barrier film with a dislocation ordered micro / nano barrier layer structure and a preparation method thereof. The preparation method comprises the following steps: performing melt blending on polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvaleric acid copolymer and non-polar long-chain alkyl amine modified inorganic nanosheet to obtain a composite material; and performing film blowing on the composite material to obtain a film. The film obtained by the method has excellent water vapor barrier performance.

Description

Technical Field

[0001] This invention relates to a high-barrier thin film with a misaligned ordered micro / nano barrier layer structure and its preparation method, belonging to the field of biodegradable thin films. Background Technology

[0002] Polybutylene terephthalate (PBAT), as a biodegradable material, possesses excellent mechanical properties and biodegradability, making it suitable for applications in packaging and agricultural mulch films. PBAT is a crucial raw material for biodegradable films and is widely used as a base resin in their preparation. Due to the specific application scenarios, food preservation films and agricultural mulch films require high barrier properties.

[0003] Currently, both single-layer and multi-layer PBAT films can be prepared using melt blown film technology. While multi-layer films offer certain advantages in barrier properties compared to single-layer films, multi-layer co-blown film technology requires a high degree of matching with the matrix resin's processing technology, resulting in complex production processes and relatively high production costs. Melt blending technology can also be used to form layered structures in PBAT, thereby improving its barrier properties. Furthermore, the blown film process for single-layer films is relatively simple, requires less equipment, and has a cost advantage.

[0004] However, constructing a multilayer barrier structure within a single-layer film to achieve high-efficiency barrier properties remains a significant technical challenge. The morphology control of the layered structure and its distribution within PBAT are crucial to the barrier performance of the PBAT film. Furthermore, excessively high layered content can lead to a loss of toughness in the PBAT material itself, making it unsuitable for some applications. These factors make constructing an efficient multilayer barrier structure within a single-layer film and preparing high-barrier PBAT films extremely difficult.

[0005] Therefore, it is necessary to provide a new preparation method to effectively improve the above-mentioned problems. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a high-barrier thin film with a misaligned ordered micro / nano barrier layer structure and its preparation method, which exhibits excellent water vapor barrier properties.

[0007] To achieve the above objectives, this invention provides a method for preparing a high-barrier film with a misaligned ordered micro / nano barrier layer structure, comprising the following steps: melt blending polybutylene terephthalate (PBAT), 3-hydroxybutyrate-3-hydroxyvalerate copolymer (PHBV), and nonpolar long-chain alkylamine-modified inorganic nanosheets to obtain a composite material; and blowing the composite material into a film to obtain a thin film. The weight ratio of PBAT, 3-hydroxybutyrate-3-hydroxyvalerate copolymer, and nonpolar long-chain alkylamine-modified inorganic nanosheets is 100:20–80:4–10, preferably 100:40–60:4–10. The nonpolar long-chain alkylamine is selected from hexadecyltrimethylammonium bromide and / or bis-hexadecyldimethylammonium bromide; the blown film head temperature is 160–180°C, the blown film draw ratio is 5–9, and the blow-up ratio is 4–5.

[0008] This invention controls the surface energy of nanosheets using nonpolar long-chain alkylamines, altering their compatibility with PHBV and PBAT. This results in stronger compatibility between the nonpolar long-chain alkylamine-modified inorganic nanosheets and PBAT, allowing them to selectively distribute within PBAT rather than PHBV, thus controlling the layer distribution. Simultaneously, this invention induces PHBV to form a micron-scale two-dimensional sheet structure through the aforementioned draw ratio and blow-up ratio, thereby creating a misaligned, ordered micro / nano-layered structure within PBAT composed of alternating PHBV microsheets and inorganic nanosheets. The nanoscale inorganic nanosheets independently distributed within PBAT, interleaved with the micron-scale PHBV sheets, create a complementary misalignment in the space of the water vapor permeation path, significantly enhancing the water vapor barrier performance of the PBAT film.

[0009] In some optional embodiments, the weight ratio of polybutylene terephthalate, 3-hydroxybutyrate-3-hydroxyvalerate copolymer, and nonpolar long-chain alkylamine modified inorganic nanosheets is 100:20 to 80:4 to 10, for example 100:40:4, 100:40:7, 100:40:10, 100:20:7, 100:60:7, 100:80:7, 100:30:7, 100:50:7, and 100:50:4.

[0010] In some alternative embodiments, the blown film head temperature is 160–180°C, for example, 160°C, 165°C, 170°C, 175°C, or 180°C.

[0011] In some alternative embodiments, the draw ratio of the blown film is 5 to 9, for example 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9.

[0012] In some alternative embodiments, the blow-up ratio of the blown film is 4 to 5, for example, 4, 4.5, or 5.

[0013] In some alternative implementations, the melt index of PBAT is 3-5 g / 10 min (test conditions: 190°C / 2.16 kg). The melt index of PHBV is 5-10 g / 10 min (test conditions: 190°C / 2.16 kg).

[0014] Furthermore, the inorganic nanosheets are selected from kaolin and / or montmorillonite.

[0015] Furthermore, the nonpolar long-chain alkylamine-modified inorganic nanosheets were prepared by the following steps: nonpolar long-chain alkylamine and inorganic nanosheets were added to water at 70–90°C and reacted for 4–8 hours. The precipitate was washed and dried in a vacuum oven at 80–90°C for 8–10 hours, then ground into powder. The weight ratio of nonpolar long-chain alkylamine to inorganic nanosheets was 0.5–1:1.

[0016] In a preferred embodiment, the nonpolar long-chain alkylamine modified nanosheets are double-chain (bis-hexadecyldimethylammonium bromide) modified montmorillonite.

[0017] Furthermore, melt blending is completed in a twin-screw extruder at a processing temperature of 180–195°C and a rotation speed of 90–140 r / min.

[0018] Furthermore, blown film production includes: first, melting the composite in a single-screw extruder at a temperature of 180–195°C to obtain a composite melt; then, reducing the temperature of the composite melt to 160–180°C; and finally, blowing the composite melt into a film.

[0019] The present invention also provides a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which is prepared by the aforementioned preparation method.

[0020] Furthermore, the thickness of the film is 10–100 μm.

[0021] For the reasons mentioned above, this high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure exhibits excellent water vapor barrier properties. Attached Figure Description

[0022] Figure 1 A schematic diagram of a high-barrier thin film with a misaligned ordered micro / nano barrier layer structure is shown in one embodiment of the present invention.

[0023] Figure 2 Scanning electron microscope (SEM) images of the PBAT / PHBV blend masterbatch in Comparative Example 4 are shown.

[0024] Figure 3A scanning electron microscope image of the PBAT / PHBV / D1 composite masterbatch in Example 2 of the present invention is shown.

[0025] Figure 4 Scanning electron microscope (SEM) images of the PBAT / PHBV / D2 composite masterbatch in Comparative Example 1 are shown.

[0026] Figure 5 Scanning electron microscope (SEM) images of the PBAT / PHBV / D3 composite masterbatch in Comparative Example 2 are shown. Detailed Implementation

[0027] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0028] All numerical specifications in this invention (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values ​​that may be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are to be understood as being preceded by the term "about". Figure 1 A schematic diagram of a high-barrier thin film with a misaligned ordered micro / nano barrier layer structure is shown in one embodiment of the present invention.

[0029] Di-hexadecyldimethylammonium bromide-modified montmorillonite: Di-hexadecyldimethylammonium bromide and sodium montmorillonite were mixed in water at 80°C and reacted for 4 hours at a weight ratio of 0.7:1. The precipitate was washed and dried in a vacuum oven at 80°C for 8 hours. It was then ground into powder to obtain di-hexadecyldimethylammonium bromide-modified montmorillonite.

[0030] 6-Aminohexanoic acid modified montmorillonite: 6-aminohexanoic acid and sodium montmorillonite were mixed in water at 80°C at a weight ratio of 0.7:1 and reacted for 4 hours. The precipitate was washed and dried in a vacuum oven at 80°C for 8 hours. It was then ground into powder to obtain 6-aminohexanoic acid modified montmorillonite.

[0031] Hexadecylmethyldihydroxyethylammonium bromide-modified montmorillonite: Hexadecylmethyldihydroxyethylammonium bromide and sodium montmorillonite were mixed in water at 80°C and reacted for 4 hours at a weight ratio of 0.7:1. The precipitate was washed and dried in a vacuum oven at 80°C for 8 hours. It was then ground into powder to obtain hexadecylmethyldihydroxyethylammonium bromide-modified montmorillonite.

[0032] Example 1

[0033] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0034] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:4.

[0035] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0036] Example 2

[0037] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0038] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0039] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0040] Example 3

[0041] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0042] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:10.

[0043] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0044] Example 4

[0045] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0046] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:20:7.

[0047] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0048] Example 5

[0049] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0050] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:60:7.

[0051] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0052] Example 6

[0053] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0054] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:80:7.

[0055] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0056] Comparative Example 1

[0057] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0058] 1) In a twin-screw extruder, polybutylene adipate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:100:7.

[0059] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a thin film.

[0060] Comparative Example 2

[0061] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0062] 1) In a twin-screw extruder, polybutylene adipate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and hexadecylmethyldihydroxyethylammonium bromide-modified montmorillonite (D2) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D2 composite masterbatch; the weight ratio of polybutylene adipate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and hexadecylmethyldihydroxyethylammonium bromide-modified montmorillonite (D2) was 100:40:7.

[0063] 2) In a single-screw extruder, the PBAT / PHBV / D2 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a thin film.

[0064] Comparative Example 3

[0065] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0066] 1) In a twin-screw extruder, polybutylene adipate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and 6-aminohexanoic acid modified montmorillonite (D3) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D3 composite masterbatch; the weight ratio of polybutylene adipate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and 6-aminohexanoic acid modified montmorillonite (D3) was 100:40:7.

[0067] 2) In a single-screw extruder, the PBAT / PHBV / D3 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a thin film.

[0068] Comparative Example 4

[0069] This comparative example provides a method for preparing a PBAT-based thin film, which includes the following steps:

[0070] 1) In a twin-screw extruder, polybutylene adipate and 3-hydroxybutyric acid-3-hydroxyvalerate copolymer are melt-blended at 180°C at a speed of 100 r / min to obtain PBAT / PHBV blend masterbatch; the weight ratio of polybutylene adipate and 3-hydroxybutyric acid-3-hydroxyvalerate copolymer is 100:40.

[0071] 2) In a single-screw extruder, the PBAT / PHBV blend masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a thin film.

[0072] Comparative Example 5

[0073] This comparative example provides a method for preparing a PBAT-based thin film, which includes the following steps:

[0074] 1) In a twin-screw extruder, polybutylene adipate terephthalate is melt-blended at 180°C with a rotation speed of 100 r / min to obtain PBAT masterbatch.

[0075] 2) In a single-screw extruder, the PBAT masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°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 165°C to obtain a PBAT film.

[0076] Table 1 shows the raw material formulations (by weight) involved in step 2) of Examples 1-6 and Comparative Examples 1-5.

[0077] Table 1

[0078] PBAT (copies) PBHV (copies) D1 (portion) D2 (portions) D3 (portions) Example 1 100 40 4 0 0 Example 2 100 40 7 0 0 Example 3 100 40 10 0 0 Example 4 100 20 7 0 0 Example 5 100 60 7 0 0 Example 6 100 80 7 0 0 Comparative Example 1 100 100 7 0 0 Comparative Example 2 100 40 0 7 0 Comparative Example 3 100 40 0 0 7 Comparative Example 4 100 40 0 0 0 Comparative Example 5 100 0 0 0 0

[0079] Figure 2 Scanning electron microscopy (SEM) images of the PBAT / PHBV blend masterbatch from Comparative Example 4 are shown. Figure 2In the image, the bright white area represents PHBV, and the dark gray area represents PBAT. PHBV can be clearly observed to be distributed in a layered structure within PBAT.

[0080] Figure 3 A scanning electron microscope (SEM) image of the PBAT / PHBV / D1 composite masterbatch from Example 2 is shown. Figure 3 In Example 2, D1 is mainly distributed in PBAT, forming an interleaved structure with the PHBV lamellar structure.

[0081] Figure 4 Scanning electron microscope (SEM) images of the PBAT / PHBV / D2 composite masterbatch in Comparative Example 2 are shown. Figure 5 Scanning electron microscope (SEM) images of the PBAT / PHBV / D3 composite masterbatch in Comparative Example 3 are shown. Figure 4 , Figure 5 In Comparative Examples 2 and 3, D2 and D3 were mainly distributed within or at the interfaces of the PHBV sheets. Furthermore, it was observed that the dimensions of the PHBV sheet-like structures in the two-dimensional direction (2-10 μm) were much larger than those of the montmorillonite nanosheets (<2 μm).

[0082] Therefore, this invention controls the surface energy of inorganic nanosheets, thereby altering their compatibility with PHBV and PBAT, and controlling the distribution of inorganic nanosheets in PBAT and PHBV. Subsequent blown film processing allows PHBV to form a micron-scale two-dimensional layered structure, ultimately resulting in a misaligned, ordered micro / nano layered structure in PBAT composed of alternating PHBV and inorganic nanosheet layers.

[0083] Table 2 shows the water vapor barrier coefficient and elongation at break of the films in Examples 1-6 and Comparative Examples 1-5.

[0084] Table 2

[0085] <![CDATA[Water vapor barrier coefficient (g·cm / m 2 ·s·Pa)]]> Elongation at break (%) Example 1 <![CDATA[1.3×10 -13 ]]> 822.1 Example 2 <![CDATA[1.0×10 -13 ]]> 790.7 Example 3 <![CDATA[0.9×10 -13 ]]> 718.5 Example 4 <![CDATA[2.1×10 -13 ]]> 1046.3 Example 5 <![CDATA[0.7×10 -13 ]]> 664.7 Example 6 <![CDATA[0.5×10 -13 ]]> 364.7 Comparative Example 1 <![CDATA[0.3×10 -13 ]]> 51.8 Comparative Example 2 <![CDATA[1.6×10 -13 ]]> 723.2 Comparative Example 3 <![CDATA[1.7×10 -13 ]]> 741.2 Comparative Example 4 <![CDATA[1.7×10 -13 ]]> 832.6 Comparative Example 5 <![CDATA[6.1×10 -13 ]]> 1260.1

[0086] In Examples 1-3, as the content of montmorillonite modified with di-long-chain alkylamine increased from 4 parts to 10 parts, the water vapor barrier coefficient of the film increased from 1.3 × 10⁻⁶. -13 g·cm / m 2 Pa decreased to 0.9 × 10⁻⁶. -13 g·cm / m 2 ·s·Pa. In Examples 2, 4-6, as the PHBV content increased from 20 parts to 80 parts, the water vapor barrier coefficient of the film increased from 2.1 × 10⁻⁶. -13 g·cm / m 2 Pa decreased to 0.5 × 10⁻⁶. -13 g·cm / m 2The elongation at break decreased from 1046.3% to 364.7%. In particular, in Example 2 and Comparative Example 5, the water vapor barrier coefficient of the PBAT / PHBV / D1 film decreased from 6.1 × 10⁻⁶ Pa to that of the PBAT film. -13 g·cm / m 2 The ·s·Pa decreased to 1.0×10 -13 g·cm / m 2 The film exhibits a water vapor barrier performance of ·s·Pa and retains an elongation at break of 790.7%. In summary, the film obtained by this invention not only significantly improves water vapor barrier performance but also possesses good toughness.

[0087] In Comparative Example 1, the water vapor barrier coefficient of the PBAT / PHBV / D1 blend film was 0.3 × 10⁻⁶. -13 g·cm / m 2 ·s·Pa, but the elongation at break of the film dropped sharply to 51.8%.

[0088] In Comparative Examples 2-4, the water vapor barrier coefficient of the PBAT / PHBV blend film was 1.7 × 10⁻⁶. -13 g·cm / m 2 The water vapor barrier coefficient of the PBAT / PHBV / D2 blend film is 1.6 × 10⁻⁶ Pa·s. -13 g·cm / m 2 The water vapor barrier coefficient of the PBAT / PHBV / D3 blend film is 1.7 × 10⁻⁶ Pa·s. -13 g·cm / m 2 As can be seen from the data, the water vapor barrier properties of PBAT / PHBV films modified with polar alkylamines D2 and D3 were not effectively improved.

[0089] Example 7

[0090] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0091] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0092] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 160°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 160°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0093] Example 8

[0094] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0095] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0096] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is 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 PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0097] Example 9

[0098] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0099] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0100] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 175°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 175°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0101] Comparative Example 6

[0102] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0103] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0104] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 155°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 155°C to obtain a thin film.

[0105] Comparative Example 7

[0106] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0107] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0108] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch was fully melted at 180°C to obtain a blend melt. Then, the blend melt was cooled to 150°C and blown at a draw ratio of 6.5, a blown ratio of 4.5, and a blown film head temperature of 150°C. It was found that no film could be formed.

[0109] Table 3 shows the water vapor barrier coefficients of the films in Examples 2, 7-9, and Comparative Examples 6-7.

[0110] Table 3

[0111] <![CDATA[Water vapor barrier coefficient (g·cm / m 2 ·s·Pa)]]> Example 2 <![CDATA[1.0×10 -13 ]]> Example 7 <![CDATA[0.9×10 -13 ]]> Example 8 <![CDATA[1.0×10 -13 ]]> Example 9 <![CDATA[0.9×10 -13 ]]> Comparative Example 6 <![CDATA[1.3×10 -13 ]]> Comparative Example 7 Unable to form a film

[0112] In Examples 2, 7, 8, and 9, the water vapor barrier coefficient of the film did not change significantly as the blown film die head temperature increased from 160°C to 175°C. This indicates that PHBV is in a molten state within the patent-protected temperature range and can be successfully extruded into blown film.

[0113] In Comparative Example 6, PHBV had already begun to crystallize in the mold. During blown film production, the PHBV dispersed phase could not be effectively stretched into sheets, and fisheye defects began to appear on the surface of the blend film.

[0114] In Comparative Example 7, PHBV had already crystallized extensively in the mold, and the blown film head pressure exceeded 25 MPa, so the extrudate could not form a film.

[0115] Example 10

[0116] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0117] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0118] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 6.5, a blow-up ratio of 4, and a blown film head temperature of 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0119] Example 11

[0120] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0121] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0122] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 6.5, a blow-up ratio of 5, and a blown film head temperature of 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0123] Example 12

[0124] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0125] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0126] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 5, a blow-up ratio of 4.5, and a blown film head temperature of 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0127] Example 13

[0128] This embodiment provides a method for preparing a high-barrier PBAT-based thin film with a misaligned ordered micro / nano barrier layer structure, which includes the following steps:

[0129] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0130] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 9, a blow-up ratio of 4.5, and a blown film head temperature of 165°C to obtain a high-barrier PBAT-based film with a misaligned ordered micro / nano barrier layer structure.

[0131] Comparative Example 8

[0132] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0133] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0134] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 6.5, a blow-up ratio of 1, and a blown film head temperature of 165°C to obtain a thin film.

[0135] Comparative Example 9

[0136] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0137] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0138] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 6.5, a blow-up ratio of 2, and a blown film head temperature of 165°C to obtain a thin film.

[0139] Comparative Example 10

[0140] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0141] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0142] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 6.5, a blow-up ratio of 3, and a blown film head temperature of 165°C to obtain a thin film.

[0143] Comparative Example 11

[0144] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0145] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0146] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 4.5, a blow-up ratio of 4.5, and a blown film head temperature of 165°C to obtain a thin film.

[0147] Comparative Example 12

[0148] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0149] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0150] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 10, a blown-up ratio of 4.5, and a blown-out die head temperature of 165°C to obtain a thin film.

[0151] Comparative Example 13

[0152] This comparative example provides a method for preparing a thin film, which includes the following steps:

[0153] 1) In a twin-screw extruder, polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) were melt-blended at 100 r / min and 180 °C to obtain PBAT / PHBV / D1 composite masterbatch; the weight ratio of polybutylene adipate terephthalate, 3-hydroxybutyric acid-3-hydroxyvalerate copolymer, and bis-hexadecyl dimethylammonium bromide modified montmorillonite (D1) was 100:40:7.

[0154] 2) In a single-screw extruder, the PBAT / PHBV / D1 composite masterbatch is fully melted at 180°C to obtain a blend melt. Then, the blend melt is cooled to 165°C and blown into a film with a draw ratio of 15, a blow-up ratio of 4.5, and a blown film head temperature of 165°C to obtain a thin film.

[0155] Table 4 shows the water vapor barrier coefficients of the films in Examples 2, 10-13, and Comparative Examples 8-13.

[0156] Table 4

[0157] <![CDATA[Water vapor barrier coefficient (g·cm / m 2 ·s·Pa)]]> Example 2 <![CDATA[1.0×10 -13 ]]> Example 10 <![CDATA[1.2×10 -13 ]]> Example 11 <![CDATA[0.9×10 -13 ]]> Example 12 <![CDATA[1.0×10 -13 ]]> Example 13 <![CDATA[1.1×10 -13 ]]> Comparative Example 8 <![CDATA[2.4×10 -13 ]]> Comparative Example 9 <![CDATA[1.8×10 -13 ]]> Comparative Example 10 <![CDATA[1.4×10 -13 ]]> Comparative Example 11 Unable to form a film Comparative Example 12 <![CDATA[1.2×10 -13 ]]> Comparative Example 13 <![CDATA[1.4×10 -13 ]]>

[0158] In Examples 2, 10, and 11, as the blow-up ratio increased from 4 to 5, the water vapor barrier coefficient of the film decreased slightly to 0.9 × 10⁻⁶. -13 g·cm / m 2 •s·Pa, barrier performance improved. In Comparative Examples 8-10, as the blow-up ratio increased from 1 to 3, the water vapor barrier coefficient of the film decreased, but the barrier performance of the film was much lower than that of the films in Examples 2, 10, and 11.

[0159] In Examples 2, 12, and 13, as the draw ratio increased from 5 to 9, the water vapor barrier coefficient of the film slightly increased to 1.1 × 10⁻⁶. -13 g·cm / m 2 In Comparative Example 11, when the draw ratio was below 5, the extrudate could not be drawn away in time, causing the material to accumulate and collide with the air ring, thus failing to form a film. In Comparative Examples 12 and 13, as the blow-up ratio increased from 10 to 15, the water vapor barrier coefficient of the film could be increased to 1.4 × 10⁻⁶ Pa. -13 g·cm / m 2 However, an excessively high draw ratio will hinder the PHBV dispersed phase from forming fibers, making it difficult to form a sheet structure, thereby reducing the barrier properties of the film.

Claims

1. A method for preparing a high-barrier thin film with a dislocation-ordered micro / nano barrier layer structure, wherein, Includes the following steps: A composite material was obtained by melt blending polybutylene terephthalate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and nonpolar long-chain alkylamine modified inorganic nanosheets. The composite material is blown into a film to obtain a thin film; The weight ratio of the polybutylene adipate terephthalate, the poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and the nonpolar long-chain alkylamine modified inorganic nanosheets is 100:20~80:4~10. The nonpolar long-chain alkylamine is selected from hexadecyltrimethylammonium bromide and / or bis-hexadecyldimethylammonium bromide; The blown film head temperature is 160~180℃, and the blown film draw ratio is 5~9 and the blow-up ratio is 4~5.

2. The preparation method according to claim 1, wherein, The weight ratio of the polybutylene adipate terephthalate, the poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and the nonpolar long-chain alkylamine modified inorganic nanosheets is 100:40~60:4~10.

3. The preparation method according to claim 1, wherein, The inorganic nanosheets are selected from kaolin and / or montmorillonite.

4. The preparation method according to claim 1, wherein, The nonpolar long-chain alkylamine modified inorganic nanosheets are prepared by the following steps: adding nonpolar long-chain alkylamine and inorganic nanosheets into water at 70~90℃ and reacting for 4~8h to obtain the nonpolar long-chain alkylamine modified inorganic nanosheets.

5. The preparation method according to claim 4, wherein, The weight ratio of the nonpolar long-chain alkylamine to the inorganic nanosheets is 0.5~1:

1.

6. The preparation method according to claim 1, wherein, The nonpolar long-chain alkylamine modified nanosheets are montmorillonite modified with double-chain (bis-hexadecyldimethylammonium bromide).

7. The preparation method according to claim 1, wherein, The melt blending is completed in a twin-screw extruder at a processing temperature of 180~195℃.

8. The preparation method according to claim 1, wherein, The rotation speed for melt blending is 90~140 r / min.

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

10. A high-barrier thin film with a misaligned ordered micro / nano barrier layer structure, wherein, It is prepared by the preparation method according to any one of claims 1-9.

11. The high-barrier thin film with a misaligned ordered micro / nano barrier layer structure according to claim 10, wherein, The thickness of the film is 10~100μm.

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