Polyhydroxyalkanoate composition and application thereof

Abstract

The invention discloses a polyhydroxyalkanoate composition and application thereof. The invention relates to a polyhydroxyalkanoate composition. The polyhydroxyalkanoate composition is prepared from the following raw materials: a polyhydroxyalkanoate polymer, polypropylene carbonate-phthalate and a processing aid, wherein the polyhydroxyalkanoate polymer is selected from one or a combination of more of poly (3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer, and the polyhydroxyalkanoate polymer is selected from one or a combination of more of poly (3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer. The weight percentage of the processing aid in the raw materials is 4-15%, and the processing aid comprises a nucleating agent, a melt flow regulator, an antioxidant, a release agent and an anti-hydrolysis agent. The polyhydroxyalkanoate composition has better processability and is easy to degrade.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of degradable plastics, and relates to a polyhydroxyalkanoate composition and application thereof, in particular, application in the preparation of injection-molded products or extrusion-molded products (such as sheets or straws). BACKGROUND

[0002] Polyhydroxyalkanoates (PHAs) are a kind of high-molecular compounds synthesized by microbial fermentation, the raw materials of which are derived from agricultural products and obtained through biological fermentation technology, and the product life ends can return to nature through the natural degradation process, and are a kind of degradable high-molecular new material derived from nature and returning to nature, which will not cause negative impact on the environment.

[0003] As a kind of high-molecular new material obtained by biological fermentation technology, under the current technical background, the batch stability of PHAs is not as good as the products produced by petroleum chemical technology, and PHAs also have some own defects in application performance, such as poor thermal stability, temperature-sensitive flowability, narrow processing temperature window, high brittleness, slow crystallization and serious post-crystallization phenomenon, etc., and it is difficult to injection-mold or extrusion-mold, and the cost is high, which is difficult to meet the needs of industrial production. At present, it is basically applied in high-end fields such as medical treatment, and cannot be popularized to the fields of packaging, agricultural film, straw tableware and other disposable plastic products. A polyhydroxyalkanoate composition is needed, which can maintain the good mechanical properties and heat resistance of polyhydroxyalkanoate while making the polyhydroxyalkanoate composition have good processing performance and low cost, and can be popularized to the fields of packaging, agricultural film, straw tableware and other disposable plastic products to replace traditional plastics. Due to the excellent degradable performance of polyhydroxyalkanoate, it will help to reduce white pollution governance.

[0004] The above information disclosed in the background section is only used to strengthen the understanding of the background of the present application, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The purpose of the present application is to provide a polyhydroxyalkanoate composition which has good processing performance and is easy to degrade. The present application also provides application of a polyhydroxyalkanoate composition in the preparation of injection-molded products or extrusion-molded products (such as sheets or straws).

[0006] The first aspect of the present application provides a polyhydroxyalkanoate composition, a raw material of the polyhydroxyalkanoate composition comprising a polyhydroxyalkanoate polymer, a polypropylene carbonate-phthalate and a processing aid; wherein the polyhydroxyalkanoate polymer comprises a combination of one or more selected from poly(3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer, and the processing aid is present in the raw material in a weight percentage of 4-15%, and the processing aid comprises a nucleating agent, a melt flow regulator, an antioxidant, a release agent and an anti-hydrolysis agent.

[0007] In some preferred embodiments, the raw material further comprises 5-30% of polybutylene adipate terephthalate. In some embodiments, the raw material further comprises 10-25% of polybutylene adipate terephthalate. More specifically, the raw material further comprises 18-22% of polybutylene adipate terephthalate.

[0008] In some preferred embodiments, the polyhydroxyalkanoate polymer is present in the raw material in a mass percentage of 50-99.5%. In some embodiments, the polyhydroxyalkanoate polymer is present in the raw material in a mass percentage of 55-95%, more preferably 55-85%. More specifically, the polyhydroxyalkanoate polymer is present in the raw material in a mass percentage of 60-80%, more preferably 60-70%.

[0009] In some embodiments, the polypropylene carbonate-phthalate is present in a mass percentage of 4-22%. Preferably, the polypropylene carbonate-phthalate is present in a mass percentage of 5-20%. In some specific embodiments, the polypropylene carbonate-phthalate is present in a mass percentage of 5%, 10%, 15% or 20%.

[0010] In some more preferred embodiments, the polyhydroxyalkanoate polymer comprises a combination of at least two selected from poly(3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer.

[0011] In some more preferred embodiments, the polyhydroxyalkanoate polymer comprises a first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer and a second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, the first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer has a lower content of 4-hydroxybutyrate than the second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, and the first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer has a higher molecular weight than the second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer. In one embodiment, the weight ratio of the first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer to the second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer is 1:4 to 4:1.

[0012] In some embodiments, the polyhydroxyalkanoate polymer consists of a (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer. Preferably, the (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer is PB3000G or Machenviron® MDF2000.

[0013] In some preferred embodiments, the nucleating agent comprises a combination of one or more selected from the group consisting of pentaerythritol, di-pentaerythritol, tri-pentaerythritol, boron nitride, talc.

[0014] In some preferred embodiments, the nucleating agent comprises tri-pentaerythritol.

[0015] In some preferred embodiments, the melt flow modifier comprises a combination of one or more selected from the group consisting of methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hyperbranched polyester polymer.

[0016] In some embodiments, the processing aid comprises 0.05 to 0.8% by weight of a nucleating agent; preferably, the nucleating agent is tri-pentaerythritol. In some embodiments, the processing aid comprises 0.05 to 0.8% by weight of a melt flow modifier; preferably, the melt flow modifier comprises hydroxypropyl cellulose.

[0017] In some embodiments, the processing aid comprises 0.05 to 0.8% by weight of an antioxidant. In some preferred embodiments, the antioxidant comprises a combination of one or more selected from the group consisting of antioxidant 1076, antioxidant 1010, antioxidant 626, and antioxidant 168, antioxidant 9228.

[0018] In some embodiments, the processing aid comprises a release agent at a weight percentage of 0.05-0.8%. In some preferred embodiments, the release agent comprises one or more combinations of high-temperature resistant lubricating dispersant 603A, pentaerythritol tristearate, vinyl bis-stearamide, calcium stearate, sodium stearate, and magnesium stearate.

[0019] In some embodiments, the processing aid includes 0.05-0.8% by weight of an anti-hydrolysis agent. In some preferred embodiments, the anti-hydrolysis agent includes one or more combinations of epoxides, carbodiimides, isocyanates, oxazolines, acid anhydrides, and glycidyl ethers.

[0020] In some specific and preferred embodiments, the raw materials of the polyhydroxyalkanoate composition, by weight percentage, include: Polyhydroxy fatty acid polymers 55-85% Polypropylene carbonate phthalate 4~22% Polybutylene terephthalate-butylene adipate 5~30% Processing aids 4-15% The polyhydroxy fatty acid polymer includes a combination of at least two selected from PB3000G, PB3430G, Machenviron® MDF1500, Machenviron® MDF2000, A1000P, and EMAT Y1000P; The processing aids include tripentaerythritol, melt flow modifier, antioxidant, mold release agent and anti-hydrolysis agent, each in a weight percentage of 0.05~0.8%; The melt flow modifier includes one or more combinations selected from methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and hyperbranched polyester polymers; The antioxidant includes one or more combinations selected from antioxidant 1076, antioxidant 1010, antioxidant 626, antioxidant 168, and antioxidant 9228; The demolding machine includes one or more of the following: high-temperature resistant lubricating dispersant 603A, pentaerythritol tristearate, vinyl bis-stearamide, calcium stearate, sodium stearate, and magnesium stearate. The anti-hydrolysis agent includes one or more combinations of epoxy compounds, carbodiimides, isocyanates, oxazolines, acid anhydrides, and glycidyl ethers.

[0021] A second aspect of the invention provides the use of the aforementioned polyhydroxyalkanoate composition in the preparation of injection-molded or extruded articles.

[0022] In some preferred embodiments, the injection-molded or extruded article comprises a sheet or straw. In some embodiments, the sheet is a plastic film suitable for preparing packaging bags or packaging films.

[0023] The present invention, by adopting the above technical solution, has the following beneficial effects: The polyhydroxyalkanoate composition of the present invention, through polymer alloy blending technology, combines specific polyhydroxyalkanoate polymers with polypropylene carbonate-phthalate, processing aids, etc., to improve the comprehensive properties of polyhydroxyalkanoate polymers to meet the needs of industrial production. While maintaining the good mechanical and heat resistance properties of polyhydroxyalkanoate itself, the polyhydroxyalkanoate composition has good processing performance and low cost, which can be widely used in packaging, agricultural film and other fields to replace traditional plastics. Due to the excellent biodegradability of polyhydroxyalkanoate itself, it will help reduce white pollution. Attached Figure Description

[0024] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The image shows the DSC (Differential Scanning Calorimetry) curve of the polyhydroxy fatty acid ester composition of Example 1.

[0026] Figure 2 The image shows the DSC (Differential Scanning Calorimetry) curve of the polyhydroxy fatty acid ester composition of Example 2.

[0027] Figure 3 The image shows the DSC (Differential Scanning Calorimetry) curve of the polyhydroxyalkanoate composition of Comparative Example 1.

[0028] Figure 4 The image shows the DSC (Differential Scanning Calorimetry) curve of the polyhydroxyalkanoate composition of Comparative Example 2.

[0029] Figure 5 A photograph of a sheet prepared from the polyhydroxyalkanoate composition of Example 13.

[0030] Figure 6 A photograph of a straw prepared from the polyhydroxyalkanoate composition of Example 13.

[0031] Figure 7 This is a photograph of the polyhydroxyalkanoate composition of Example 13 during extrusion.

[0032] Figure 8This is a photograph of the composition of Comparative Example 5 during extrusion.

[0033] Figure 9 Photographs of the polyhydroxyalkanoate composition prepared for Example 13 before and after degradation experiments. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art. It should be noted that the description of these embodiments is for the purpose of aiding understanding the present invention, but does not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Polyhydroxyalkanoates (PHAs) are biodegradable polymers derived from renewable resources and obtained through biotechnology. PHAs possess excellent mechanical and heat resistance properties, but also suffer from drawbacks such as a narrow processing window, temperature-sensitive flowability, high brittleness, and severe post-crystallization. This invention utilizes polymer alloy blending technology to improve the overall performance of PHAs by compounding them with other biodegradable polymers, thereby meeting the performance requirements of raw materials for downstream product manufacturing and continuous production. The base raw materials of the polyhydroxyalkanoate composition include polyhydroxyalkanoate polymers and polypropylene carbonate-phthalate, wherein the polyhydroxyalkanoate polymers constitute 50-99.5% by mass of the raw materials, and the polypropylene carbonate-phthalate constitutes 4-22% by mass of the raw materials. In some embodiments, the base raw materials of the polyhydroxyalkanoate composition may further include polybutylene terephthalate (PET), forming a ternary blend system; wherein PET constitutes 5-30% by mass of the raw materials. In addition to the base raw materials, the polyhydroxyalkanoate composition contains 4-15% by weight of processing aids. Processing aids may include nucleating agents, melt flow modifiers, antioxidants, release agents, and anti-hydrolysis agents.

[0036] The polyhydroxy fatty acid polymer comprises a combination of one or more selected from poly(3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer, and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer. In some embodiments, the polyhydroxy fatty acid polymer comprises a combination of at least two selected from poly(3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer, and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer. In some embodiments, the polyhydroxy fatty acid polymer includes a (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer and / or a (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer; wherein the (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer includes a first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer and a second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, wherein the content of 4-hydroxybutyrate in the first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer is less than the content of 4-hydroxybutyrate in the second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer; and / or, the molecular weight of the first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer is higher than the molecular weight of the second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer. For example, polyhydroxy fatty acid polymers include combinations of at least two selected from PB3000G, PB3430G, Machenviron® MDF1500, Machenviron® MDF2000, A1000P, and EMAT Y1000P.

[0037] The processing aid includes a nucleating agent at a weight percentage of 0.05-0.8%. The nucleating agent includes one or more combinations selected from pentaerythritol, dipentaerythritol, tripentaerythritol, boron nitride, and talc. In a specific embodiment, the nucleating agent is tripentaerythritol.

[0038] The processing aid includes a melt flow modifier at a weight percentage of 0.05-0.8%. The melt flow modifier includes one or more combinations selected from methylcellulose, hydroxypropylcellulose, hydroxypropyl methylcellulose, and hyperbranched polyester polymers. In a specific embodiment, the melt flow modifier includes hydroxypropylcellulose.

[0039] The processing aids include antioxidants at a weight percentage of 0.05 to 0.8%. The antioxidants include one or more combinations selected from antioxidants 1076, 1010, 626, 168, and 9228.

[0040] Processing aids include a release agent at a weight percentage of 0.05-0.8%. The release agent includes one or more of the following: high-temperature resistant lubricating dispersant 603A, pentaerythritol tristearate, vinyl bis-stearamide, calcium stearate, sodium stearate, and magnesium stearate.

[0041] The processing aids include 0.05-0.8% by weight of an anti-hydrolysis agent. The anti-hydrolysis agent includes one or more combinations of epoxy compounds, carbodiimides, isocyanates, oxazolines, acid anhydrides, and glycidyl ethers.

[0042] The raw materials for the polyhydroxyalkanoate composition may include, by weight percentage: Polyhydroxy fatty acid polymers 55-85% Polypropylene carbonate phthalate 4~22% Polybutylene terephthalate-butylene adipate 5~30% Processing aids 4-15% The polyhydroxyalkanoic acid polymer comprises a combination of at least two selected from PB3000G, PB3430G, Machenviron® MDF1500, Machenviron® MDF2000, A1000P, and EMAT Y1000P; the processing aid comprises tripentaerythritol, melt flow modifier, antioxidant, release agent, and anti-hydrolysis agent, each at a weight percentage of 0.05-0.8%. The melt flow modifier may be hydroxypropyl cellulose.

[0043] The above-described polyhydroxyalkanoate compositions are suitable for use in the preparation of injection-molded or extruded articles. Injection-molded or extruded articles include sheets or straws. Sheets may be plastic films suitable for preparing single-use plastic products such as packaging bags or films, and straws.

[0044] The present invention will be described in detail below through specific embodiments.

[0045] raw materials Polyhydroxy-3-yl-butyrate (P34HB): Grade: MDF1000, Zhuhai Medbio Biotechnology Co., Ltd. Poly(3-hydroxybutyrate)-co-4-polyhydroxybutyrate (P34HB), brand name: PB3000G, Beijing Microstructure Factory Biotechnology Co., Ltd. Poly(3-hydroxybutyrate)-co-4-polyhydroxybutyrate (P34HB), brand name: PB3430G, Beijing Microstructure Factory Biotechnology Co., Ltd. Poly(3-hydroxybutyrate)-co-4-polyhydroxybutyrate (P34HB), brand name: Machenviron® MDF1500, Zhuhai Maidefa Biotechnology Co., Ltd. Poly(3-hydroxybutyrate)-co-4-polyhydroxybutyrate (P34HB), brand name: Machenviron® MDF2000, Zhuhai Maidefa Biotechnology Co., Ltd. Poly(3-hydroxybutyrate)-co-4-polyhydroxybutyrate (P34HB), grade: A1000P, PT CheiljedangIndonesia Poly(3-hydroxybutyrate)-co-3-polyhydroxyvalerate (PHBV), grade: Y1000P, Ningbo Tianan Biomaterials Co., Ltd. Polypropylene carbonate-phthalate (PPC-P): Grade: LX101, Shandong Lianxin Environmental Protection Technology Co., Ltd. Polybutylene terephthalate (PBAT), brand name: HF101, Huafeng Group Co., Ltd. Release Agent 603A: High-Temperature Resistant Lubricating Dispersant 603A, Qingdao Sainuo New Materials Co., Ltd. Calcium stearate: Anhui Shafeng New Materials Co., Ltd. Pentaerythritol stearate (PETS): Kesai Success (Zhejiang) New Material Technology Co., Ltd. Hyperbranched polyester polymer, brand name: Hyper C181, Wuhan Hyperbranched Resin Technology Co., Ltd. Tripentaerythritol: Yunnan Yuntianhua Co., Ltd. Talc: Shenzhen Jinhaohui Industrial Development Co., Ltd. Nano-montmorillonite: Zhejiang Fenghong New Material Co., Ltd. Anti-hydrolysis agent: Joncryl ADR-4468, BASF Test method: The melt flow index test method is based on ISO 1133.

[0046] The tensile property test method refers to ISO 527-2:1993 Determination of tensile properties of plastics, Part 2: Test conditions for molding and extrusion plastics; The bending performance test method refers to ISO 178:2001 Plastics bending performance test; The notched impact and unnotched impact test methods are in accordance with ISO 180.

[0047] Nucleating agents The raw materials were mixed according to Table 1, and extruded using a screw extruder to obtain the polyhydroxyalkanoate compositions of Examples 1 and 2 and Comparative Examples 1 and 2. Their crystallinity was determined by differential scanning calorimetry (DSC), and the results are shown in Table 1 and 2. Figures 1 to 4 .

[0048]

[0049] Boron nitride is expensive; even at concentrations between 0.5% and 1.0%, it increases the raw material cost of the product by more than 5%. Tripentaerythritol, on the other hand, is a conventional chemical product with a low price, and talc is even cheaper. It does not increase the cost of raw materials and its effect on improving the crystallinity of the product is comparable to that of boron nitride.

[0050] Melt flow regulators The raw materials were mixed according to Table 2 and extruded through a screw extruder to obtain the polyhydroxy fatty acid ester compositions of Examples 3-7 and Comparative Example 3. The performance test results are shown in Table 2.

[0051]

[0052] Examples 8-12 The raw materials were mixed according to Table 3 and extruded through a screw extruder to obtain the polyhydroxy fatty acid ester compositions of Examples 8-12. The performance test results are shown in Table 3.

[0053]

[0054] Examples 13-18 The raw materials were mixed according to Table 4 and extruded through a screw extruder to obtain the polyhydroxy fatty acid ester compositions of Examples 13-18. The performance test results are shown in Table 4.

[0055]

[0056] Comparative Examples 4-8 The raw materials were mixed according to Table 5 and extruded through a screw extruder to obtain the polyhydroxy fatty acid ester compositions of Comparative Examples 4 to 8. The performance test results are shown in Table 5.

[0057]

[0058] Referring to Tables 4 and 5, the examples demonstrate that in binary or ternary blends comprising polyhydroxyalkanoate compositions, synergistic effects with specific processing aids improve the processing performance while maintaining good mechanical properties, resulting in melt flow index and crystallinity properties suitable for injection molding or extrusion. This polyhydroxyalkanoate composition can be processed into plastic masterbatches using a screw extruder and further processed into plastic sheets (such as… Figure 5 (as shown) or a straw (such as)Figure 6 (As shown).

[0059] See also Figure 7 The polyhydroxyalkanoate composition of the example exhibits a uniform melt during extrusion; while the comparative example... Figure 8 The comparative polyhydroxy fatty acid ester composition exhibited uneven melt distribution during extrusion.

[0060] Degradation experiment: Samples of the polyhydroxyalkanoate composition from Example 16 were immersed in an aquarium for 150 days. See also Figure 9 The darker colored specimens were those that were not soaked, while the lighter colored specimens, after being soaked in the aquarium for 150 days, showed significant degradation, with their length, width, and thickness all decreasing significantly compared to the unsoaked specimens.

[0061] The polyhydroxyalkanoate composition of the present invention does not require harsh degradation conditions (such as industrial composting) and can be treated using methods such as home composting and soil degradation. The polyhydroxyalkanoate composition (Example 16) achieves a degradation rate of 33% under natural conditions (simulating home composting conditions) for 60 days.

[0062] As indicated in this specification and claims, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, and these steps and elements do not constitute an exclusive list; the method or apparatus may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0063] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. In the event of any contradiction or inconsistency between the definitions used herein and those contained in other published documents, the definitions used herein shall prevail.

[0065] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are preferred embodiments. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and they should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made according to the principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A polyhydroxyalkanoate composition, characterized in that, The raw materials of the polyhydroxy fatty acid ester composition include polyhydroxy fatty acid polymers, polypropylene carbonate-phthalate, and processing aids; wherein the polyhydroxy fatty acid polymers include one or more combinations selected from poly(3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer, and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer; the processing aids are 4-15% by weight in the raw materials, and the processing aids include nucleating agents, melt flow modifiers, antioxidants, release agents, and anti-hydrolysis agents.

2. The polyhydroxyalkanoate composition according to claim 1, characterized in that, The raw materials also include 5-30% polybutylene terephthalate (PET).

3. The polyhydroxyalkanoate composition according to claim 1 or 2, characterized in that, The polyhydroxy fatty acid polymer is present in the raw material at a mass percentage of 50-99.5%.

4. The polyhydroxyalkanoate composition according to claim 3, characterized in that, The polyhydroxy fatty acid polymers include combinations of at least two selected from poly(3-hydroxybutyrate), (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer and (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer.

5. The polyhydroxyalkanoate composition according to claim 4, characterized in that, The polyhydroxy fatty acid polymer includes a first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer and a second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, wherein the content of 4-hydroxybutyrate in the first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer is less than the content of 4-hydroxybutyrate in the second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer, and the molecular weight of the first (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer is higher than the molecular weight of the second (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer.

6. The polyhydroxyalkanoate composition according to claim 1, characterized in that, The nucleating agent includes one or more combinations selected from pentaerythritol, dipentaerythritol, tripentaerythritol, boron nitride, and talc.

7. The polyhydroxyalkanoate composition according to claim 1, characterized in that, The nucleating agent includes tripentaerythritol.

8. The polyhydroxyalkanoate composition according to claim 1, characterized in that, The melt flow modifier includes one or more combinations selected from methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and hyperbranched polyester polymers.

9. The polyhydroxyalkanoate composition according to claim 1, characterized in that, The raw materials for the polyhydroxyalkanoate composition, by weight percentage, include: Polyhydroxy fatty acid polymers 55-85% Polypropylene carbonate phthalate 4~22% Polybutylene terephthalate-butylene adipate 5~30% Processing aids 4-15% The polyhydroxy fatty acid polymer includes a combination of at least two selected from PB3000G, PB3430G, Machenviron® MDF1500, Machenviron® MDF2000, A1000P, and Y1000P; The processing aids include tripentaerythritol, melt flow modifier, antioxidant, mold release agent and anti-hydrolysis agent, each in a weight percentage of 0.05~0.8%; The melt flow modifier includes one or more combinations selected from methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and hyperbranched polyester polymers; The antioxidant includes one or more combinations selected from antioxidant 1076, antioxidant 1010, antioxidant 626, antioxidant 168, and antioxidant 9228; The demolding machine includes one or more of the following: high-temperature resistant lubricating dispersant 603A, pentaerythritol tristearate, vinyl bis-stearamide, calcium stearate, sodium stearate, and magnesium stearate. The anti-hydrolysis agent includes one or more combinations of epoxy compounds, carbodiimides, isocyanates, oxazolines, acid anhydrides, and glycidyl ethers.

10. The use of a polyhydroxyalkanoate composition according to any one of claims 1 to 9 in the preparation of injection-molded or extruded articles.

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