A polyhydroxyalkanoate composition, a method for producing the same, a biodegradable plastic product, and an application thereof

Abstract

The application provides a polyhydroxyaliphatic ester composition and a preparation method thereof, a biodegradable plastic product and application thereof. The biodegradable plastic product is prepared by the following method, which comprises the following steps: mixing at least two kinds of 3-hydroxybutyrate and 4-hydroxybutyrate copolymers, melting, extruding and granulating to obtain polyhydroxyaliphatic ester particles; the at least two kinds of 3-hydroxybutyrate and 4-hydroxybutyrate copolymers at least include a block copolymer with a mass percentage of 4-hydroxybutyrate structural unit of 0-20%, and at least include a random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate; the polyhydroxyaliphatic ester particles are formed to obtain a preformed part; and the preformed part is post-processed to obtain the biodegradable plastic product. The biodegradable plastic product has excellent toughness, low migration, good processing and forming performance and low odor.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable materials technology, specifically relating to a polyhydroxyalkanoate composition and its preparation method, biodegradable plastic products and their applications. Background Technology

[0002] Small-sized plastic products, as typical examples of single-use plastic products, are often discarded carelessly after use due to their small size, light weight, and low recycling value. They eventually enter marine and terrestrial ecosystems, causing persistent damage to the natural environment and resulting in serious environmental pollution problems.

[0003] Furthermore, the recycling of small-sized plastic products faces multiple technical challenges and economic obstacles. From a physical perspective, small-sized plastic products are small in size and light in weight (approximately 0.4 grams), making them easily missed or mixed with other impurities during recycling and sorting, hindering effective separation. From an economic perspective, the cost of recycling small-sized plastic products far exceeds their value as recycled materials, resulting in a lack of incentive for recycling companies. For example, traditional small-sized plastic products (made of polyethylene, polypropylene, etc.) are difficult to recycle, with degradation cycles in the natural environment reaching hundreds of years. Once in the ocean, they decompose into microplastics, which can be ingested by marine life and enter the food chain, potentially threatening human health. In addition, the environmental impact of small-sized plastic products is also reflected in their carbon emissions throughout their entire life cycle. From oil extraction and refining to plastic production and product manufacturing, the carbon footprint of the entire process is considerable.

[0004] Polylactic acid (PLA) was an early biodegradable material to replace traditional small-sized plastic products. However, in practical applications, PLA has revealed many limitations, especially its demanding degradation conditions, which are difficult to meet real-world needs. Although PLA is theoretically biodegradable, it requires a strict industrial composting environment—typically requiring a temperature of 50-60°C, certain humidity, and the presence of specific microorganisms—and several months to completely degrade. These conditions are difficult to achieve in ordinary natural environments, resulting in PLA straws degrading extremely slowly in the ocean or soil, almost indistinguishable from traditional plastics, still posing a certain degree of environmental burden. Therefore, there is a strong market demand for disposable small-sized plastic products that can degrade under natural conditions and have low carbon emissions throughout their entire life cycle.

[0005] In summary, small-sized plastic products, as disposable plastic items used extensively in daily life, have long caused serious pollution to the global environment. The difficulty in recycling traditional small-sized plastic products and the stringent degradation conditions for PLA and other plastic products (such as PLA straws) have driven the research and application of fully biodegradable PHA (polyhydroxyalkanoate) small-sized plastic products. With its 100% bio-based origin and complete degradation in natural environments, PHA small-sized plastic products have become an ideal alternative to solving the pollution problem of small-sized plastic products. However, the strength and toughness of PHA need further improvement, and it has poor post-brittleness. Addressing these issues would lead to poor processing and molding performance and migration resistance, resulting in products with high odor and poor appearance quality, affecting their usability.

[0006] Therefore, developing a biodegradable plastic product that combines good strength and toughness, significantly improves post-brittleness, has good processability and molding properties, is resistant to migration, and has low odor is an urgent problem to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a polyhydroxyalkanoate composition and its preparation method, as well as biodegradable plastic products and their applications. The polyhydroxyalkanoate composition solves the problems of existing polyhydroxyalkanoate materials, such as the inability to simultaneously achieve good strength and toughness, poor post-processing brittleness, low processing efficiency, and easy migration. The biodegradable plastic product exhibits excellent toughness, low migration, good processing and molding performance, and low odor.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a polyhydroxyalkanoate composition comprising at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate; wherein at least one of the at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate comprises a block copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate, wherein the mass percentage of 4-hydroxybutyrate structural units in the block copolymer is 0-20%; wherein at least one of the at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate comprises a random copolymer of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) (random P34HB); wherein the mass percentage of 4-hydroxybutyrate structural units in the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate is 15-31%.

[0010] In this invention, the 3-hydroxybutyrate and 4-hydroxybutyrate copolymer includes at least a block copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of 0-20% of a 4-hydroxybutyrate structural unit and a random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of 15-31% of a 4-hydroxybutyrate structural unit. This is beneficial for improving the strength and toughness of polyhydroxybutyrate materials, reducing their brittleness, and ensuring that the polyhydroxybutyrate materials also have good processing performance and low migration.

[0011] In this invention, the mass percentage of the 4-hydroxybutyrate structural unit is 0-20%, for example, it can be 0%, 2%, 5%, 8%, 10%, 12%, 15%, 16%, 18%, etc.

[0012] In this invention, the mass percentage of 4-hydroxybutyrate structural units in the block copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate is 0%, which indicates that the composition contains hydroxybutyrate homopolymer.

[0013] In this invention, the mass percentage of the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate in the polyhydroxy fatty acid ester composition is preferably 9-30%, for example, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, etc.; more preferably 10-17%.

[0014] Preferably, the mass percentage of 4-hydroxybutyrate structural units in the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate is 15-31%, for example, it can be 15%, 16%, 18%, 20%, 22%, 25%, 27%, 28%, 30%, 31%, etc., more preferably 20-30%.

[0015] Preferably, the at least two 3-hydroxybutyrate and 4-hydroxybutyrate copolymers include a block copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of at least one 4-hydroxybutyrate structural unit of <10% (e.g., 0%, 2%, 4%, 6%, 8%, etc.) and a block copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of at least one 4-hydroxybutyrate structural unit of ≥10% and ≤20% (e.g., 11%, 12%, 14%, 15%, 16%, 18%, etc.).

[0016] Preferably, the mass percentage of the block copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate in the polyhydroxy fatty acid ester composition is 10-30%, for example, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, etc.; more preferably, 15-20%.

[0017] In this invention, the addition of block P34HB with a specific content of 4-hydroxybutyrate structural units of ≥10% and ≤20% by mass and random P34HB is beneficial to further improve the post-brittleness of the material.

[0018] In this invention, the at least two 3-hydroxybutyrate and 4-hydroxybutyrate copolymers further include at least one copolymer with a 4-hydroxybutyrate structural unit content of 0% by mass, that is, at least one poly3-hydroxybutyrate.

[0019] In this invention, copolymers with high 4HB content have excellent toughness, which can improve the toughness of the product and reduce its post-brittleness, but it will affect the processing and molding of the product. By using a copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate to compound poly3-hydroxybutyrate, both toughness and processing and molding performance can be taken into account, and the post-brittleness of the material can be further improved.

[0020] In this invention, the 3-hydroxybutyrate and 4-hydroxybutyrate copolymer can be derived from powder obtained by bio-fermentation.

[0021] Preferably, the polyhydroxyalkanoate composition further includes inorganic fillers and nucleating agents.

[0022] Preferably, the polyhydroxyalkanoate composition comprises, by weight, 35-99.9 parts (e.g., 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, etc.) of at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate, and further comprises 9-25 parts by weight of inorganic filler and nucleating agent, for example, 9.5 parts, 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, 15.5 parts, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, etc.

[0023] Preferably, the mass of the nucleating agent in the polyhydroxyalkanoate composition is 0.1 to 5 parts, for example, it can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, etc.

[0024] Preferably, the inorganic filler and nucleating agent each independently comprise any one or more combinations of talc, calcined kaolin, magnesium silicate, titanium dioxide, boron nitride, borax, bentonite, magnesium oxide, manganese oxide, nepheline syenite, zinc oxide, iron oxide, carbon black, glass wool, glass fiber, feldspar, tin dioxide, sodium magnesium aluminosilicate, calcium silicate, calcium aluminum silicate, diatomite, zinc phosphate, magnesia carbide, calcium sulfate, aluminum, sodium sulfite, sodium bisulfite, calcite, magnesium iron tetroxide, silicon carbide, iron, mica, wollastonite, calcium carbonate, silicon dioxide, aluminum oxide, barium sulfate, or montmorillonite; more preferably, any one or more combinations of talc, calcined kaolin, titanium dioxide, calcite, silicon carbide, iron, aluminum, bentonite, boron nitride, or magnesium silicate.

[0025] In this invention, the inorganic filler is more preferably any one or more combinations of talc, calcined kaolin, or magnesium silicate; the nucleating agent is more preferably titanium dioxide and / or boron nitride.

[0026] Preferably, the inorganic filler has a mesh size of 1000-5000 mesh, such as 1000 mesh, 1500 mesh, 2000 mesh, 2500 mesh, 3000 mesh, 3200 mesh, 3400 mesh, 3600 mesh, 3800 mesh, 4000 mesh, 4200 mesh, 4400 mesh, 4600 mesh, 4800 mesh, 5000 mesh, etc.

[0027] In this invention, the core agent is used without specifying the mesh size.

[0028] In this invention, inorganic fillers and nucleating agents can promote nucleation, increase crystallization rate, and refine grains through heterogeneous nucleation, thereby improving the post-brittleness of the polyhydroxyalkanoate composition and reducing costs. Furthermore, the mesh size of the inorganic filler is within a specific range, which is beneficial to further improve the toughness of the material, improve post-brittleness, and at the same time take into account molding and processing performance.

[0029] Preferably, the polyhydroxyalkanoate composition further comprises 0.1 to 4 parts by weight of a chain extender, such as 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, etc.

[0030] Preferably, the chain extender includes epoxy chain extenders and / or ammonia chain extenders, more preferably epoxy chain extenders.

[0031] Preferably, the epoxy chain extender comprises an acrylate polymer containing epoxy groups.

[0032] In this invention, the addition of chain extenders helps to repair broken molecular chains, improve processing efficiency, enhance the toughness of the polyhydroxyalkanoate composition, improve its brittleness, and reduce the migration of the polyhydroxyalkanoate composition.

[0033] In this invention, epoxy chain extenders are preferred because they have high reaction efficiency with polyhydroxy fatty acid esters. Compared with ammonia chain extenders, they reduce the probability of side reactions, reduce migration, and avoid food safety issues.

[0034] Preferably, the polyhydroxyalkanoate composition further includes, by weight, at least one of 0.2 to 10 parts compatibilizer, 0.1 to 5 parts antioxidant, 0.1 to 5 parts lubricant, and 0.5 to 5 parts toughening agent.

[0035] In this invention, 0.2 to 10 parts of compatibilizer can be, for example, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, etc.

[0036] In this invention, 0.1 to 5 parts of antioxidant can be, for example, 0.1 parts, 0.2 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

[0037] In this invention, 0.1 to 5 parts of lubricant can be, for example, 0.1 parts, 0.2 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

[0038] In this invention, the toughening agent is 0.1 to 5 parts, for example, 0.1 parts, 0.2 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

[0039] In this invention, the compatibilizer includes, but is not limited to, maleic anhydride-grafted polyethylene (PE-g-MAH), maleic anhydride-grafted polypropylene (PP-g-MAH), maleic anhydride-grafted polyolefin elastomer (POE-g-MAH), and glycidyl methacrylate-grafted polyolefin elastomer (PE-g-GMA); the antioxidant includes, but is not limited to, hindered phenolic antioxidants, phosphate ester antioxidants, and thioester antioxidants; exemplary, the antioxidants include, but are not limited to, antioxidant 1010, antioxidant 1076, antioxidant DLTDP, antioxidant DSTDP, and antioxidant... Agent 168, etc.; the lubricant includes, but is not limited to, ethylene bis-stearamide, stearic acid, polyethylene wax, ethylene-vinyl acetate wax, monopolyester wax, glyceryl stearate (GMS), stearates (such as calcium stearate, magnesium stearate, zinc stearate, etc.), amide waxes (such as vinyl bis-stearamide EBS, erucamide, oleamide, etc.), pentaerythritol stearate (PETS), etc.; the toughening agent includes, but is not limited to, styrene-butadiene rubber, ethylene propylene rubber, nitrile rubber, styrene-butadiene-styrene block polymer, hydrogenated styrene-butadiene-styrene block polymer, polyolefin elastomer, etc.

[0040] In this invention, the additives are not limited to those mentioned above. Additives with corresponding functions can be selected according to actual needs. For example, colorants, anti-hydrolysis agents, coupling agents, etc. can also be added, which will not be elaborated here.

[0041] Preferably, the weight-average molecular weight of the polyhydroxyalkanoate composition is 200,000 to 600,000, for example, it can be 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, etc.; more preferably, it is 300,000 to 450,000.

[0042] Preferably, at 190°C and 2.16 kg, the melt index of the polyhydroxyalkanoate composition is 1-10 g / 10 min, for example, 1 g / 10 min, 2 g / 10 min, 4 g / 10 min, 6 g / 10 min, 8 g / 10 min, or 10 g / 10 min; more preferably, 3-9 g / 10 min.

[0043] In a second aspect, the present invention provides a method for preparing the polyhydroxy fatty acid ester composition described in the first aspect, the method comprising the following steps: mixing at least two 3-hydroxybutyrate and 4-hydroxybutyrate copolymers, melting, and extruding to obtain the polyhydroxy fatty acid ester composition.

[0044] In this invention, the form of the polyhydroxyalkanoate composition is not limited, including but not limited to particles, lines, profiles, etc.

[0045] Preferably, the mixed material further includes at least one of inorganic fillers, nucleating agents, chain extenders, compatibilizers, antioxidants, lubricants, or toughening agents.

[0046] Preferably, the melting temperature is 60~200℃, for example, it can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 180℃, 200℃, etc.

[0047] Preferably, the extrusion temperature is 60~200℃, for example, it can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 180℃, 200℃, etc.

[0048] In this invention, the equipment for melting and extrusion includes, but is not limited to, internal mixers, single-screw extruders, twin-screw extruders, etc.

[0049] Thirdly, the present invention provides a biodegradable article prepared using the polyhydroxyalkanoate composition described in the first aspect.

[0050] Preferably, the shape of the biodegradable product includes at least one of tubular, hollow, and membrane shapes.

[0051] Preferably, the molding method of the biodegradable product includes at least one of injection molding, compression molding, extrusion molding, extrusion blow molding, biaxial stretching molding, and uniaxial stretching molding.

[0052] In this invention, the biodegradable products include, but are not limited to, small-sized plastic products such as straws, film bags, and bottles.

[0053] To achieve this objective, the present invention adopts the following technical solution:

[0054] Fourthly, the present invention provides a biodegradable plastic product, which is prepared by the following method, the method comprising the following steps: (1) mixing at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate, melting, extruding and granulating to obtain polyhydroxybutyrate particles; the at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate include at least one block copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of 0-20% of 4-hydroxybutyrate structural units; the at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate include at least one random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate; the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate has a mass percentage of 4-hydroxybutyrate structural units of 15-31%; (2) molding the polyhydroxybutyrate particles obtained in step (1) to obtain a preform; (3) post-processing the preform obtained in step (2) to obtain the biodegradable plastic product.

[0055] In this invention, the biodegradable plastic product is produced by using a specific formula and a specific process. The resulting product has high strength and toughness, significantly improved post-brittleness, good processing and molding properties, migration resistance, and low odor.

[0056] Preferably, the mass percentage of the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate in the polyhydroxy fatty acid ester particles in step (1) is 9-30%, for example, it can be 10%, 12%, 15%, 18%, 20%, 22%, 24%, 26%, 28%, etc.; more preferably, it is 10-17%.

[0057] Preferably, the polyhydroxyalkanoate particles in step (1) further include inorganic fillers and nucleating agents.

[0058] Preferably, by weight, the polyhydroxyalkanoate particles comprise 35-99.9 parts (e.g., 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, etc.) of copolymers of at least two types of 3-hydroxybutyrate and 4-hydroxybutyrate, and further comprise 9-25 parts by total mass (e.g., 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 19, 20, 21, 22, 23, 24, 25, etc.) of inorganic fillers and nucleating agents.

[0059] Preferably, by weight, the polyhydroxyalkanoate particles in step (1) further include 0.1 to 4 parts of chain extender, for example, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, etc.

[0060] Preferably, by weight, the polyhydroxyalkanoate particles in step (1) further include at least one of the following: 0.2 to 10 parts compatibilizer, 0.1 to 5 parts antioxidant, 0.1 to 5 parts lubricant, and 0.5 to 5 parts toughening agent.

[0061] Preferably, the weight-average molecular weight of the polyhydroxy fatty acid ester particles in step (1) is 200,000 to 600,000, for example, it can be 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, etc.; more preferably, it is 300,000 to 450,000.

[0062] Preferably, under the conditions of 190°C and 2.16 kg, the melt index of the polyhydroxyalkanoate particles in step (1) is 1-10 g / 10 min, for example, it can be 1 g / 10 min, 2 g / 10 min, 4 g / 10 min, 6 g / 10 min, 8 g / 10 min, or 10 g / 10 min; more preferably, it is 3-9 g / 10 min.

[0063] Preferably, the melting temperature in step (1) is 60~200℃, for example, it can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 180℃, 200℃, etc.; preferably 110~160℃.

[0064] Preferably, the extrusion temperature in step (1) is 60~200℃, for example, it can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 180℃, 200℃, etc.

[0065] Preferably, the extrusion in step (1) includes extrusion through a first temperature zone, a second temperature zone, a third temperature zone, and temperature zone A in sequence.

[0066] In this invention, the temperature of temperature zone A refers to the mold temperature.

[0067] Preferably, the temperature of the first temperature zone is 90~130℃, for example, it can be 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, etc.; the temperature of the second temperature zone is 100~135℃, for example, it can be 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, etc.; the temperature of the third temperature zone is 100~145℃, for example, it can be 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, etc.; the temperature of temperature zone A is 130~150℃, for example, it can be 135℃, 140℃, 145℃, etc.

[0068] Preferably, a fourth temperature zone is further included between the third temperature zone and temperature zone A, and the temperature of the fourth temperature zone is 110~150℃, for example, it can be 115℃, 120℃, 125℃, 140℃, 135℃, 140℃, 145℃, etc.

[0069] In this invention, the extrusion temperature is within a specific range, which can balance a faster crystallization rate and a larger number of crystal nuclei; thus, the resulting product has both high toughness and molding performance, while also having good appearance quality, fewer surface defects, and a high yield.

[0070] Preferably, the extrusion speed in step (1) is 100~400 rpm, for example, 120 rpm, 150 rpm, 180 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, etc.

[0071] Preferably, the diameter of the screw used in the extrusion of step (1) is 50~80mm, for example, it can be 52 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 78 mm, etc.; more preferably, it is 60~70mm.

[0072] In this invention, the screw diameter used in the extrusion is within a specific range, which is beneficial to improving melt strength and the molding performance of the product.

[0073] Preferably, the molding method in step (2) includes at least one of injection molding, compression molding, extrusion molding, extrusion blow molding, vacuum forming, casting, biaxial stretching molding, uniaxial stretching molding, injection stretch blow molding, and injection blow molding.

[0074] Preferably, the diameter of the screw used in step (2) is 50~80mm, for example, it can be 52 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 78 mm, etc.; more preferably, it is 60~70mm.

[0075] Preferably, the molding temperature in step (2) is 100~300℃, for example, it can be 120℃, 150℃, 180℃, 200℃, 220℃, 250℃, 280℃, etc.

[0076] Preferably, the molding process includes molding in sequence through a first stage, a second stage, a third stage, and a fourth stage.

[0077] Preferably, the temperature of the first stage is 158~198℃, for example, it can be 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, etc.; the temperature of the second stage is 136~176℃, for example, it can be 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, etc.; the temperature of the third stage is 150~190℃, for example, it can be 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, etc.; the temperature of the fourth stage is 150~190℃, for example, it can be 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, etc.

[0078] In this invention, the molding temperature and screw diameter are within a specific range, which is beneficial to improve the toughness of the product, reduce post-brittleness, improve molding performance, and at the same time make the product have good appearance quality, fewer surface defects, and high yield.

[0079] Preferably, the post-processing in step (3) includes water bath shaping of the preform.

[0080] Preferably, the temperature of the water bath is 45~60℃, for example, it can be 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃, etc.

[0081] In this invention, post-treatment using a water bath at a specific temperature is beneficial for promoting crystallization and shaping, reducing secondary crystallization, and improving the brittleness of the product.

[0082] Preferably, the water bath shaping treatment further includes a drying step.

[0083] Preferably, the drying temperature is 60~100℃, for example, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, etc.; the drying time is 1~10h, for example, 2h, 4h, 6h, 8h, etc.

[0084] In this invention, the drying process can further promote crystallization and reduce the odor of the product.

[0085] Fifthly, the present invention provides an application of the biodegradable plastic product described in the fourth aspect in tableware and packaging materials.

[0086] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0087] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0088] The polyhydroxyalkanoate composition provided by this invention includes at least a copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of 0-20% of a 4-hydroxybutyrate structural unit, and a random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of 15-31% of a 4-hydroxybutyrate structural unit. This composition is beneficial for improving the strength and toughness of polyhydroxyalkanoate materials, reducing their brittleness, and ensuring that the polyhydroxyalkanoate materials also have good processing performance and low migration. As a result, the polyhydroxyalkanoate composition does not require the addition of large amounts (<1%) of other types of polymers, and can meet the requirements for marine degradation by using only polyhydroxyalkanoate homologues.

[0089] The biodegradable products provided by this invention, using a specific formula and a specific process, result in products with high strength and toughness, significantly improved post-brittleness, good processing and molding properties, migration resistance, low odor, good appearance quality, few defects, and high yield. Attached Figure Description

[0090] Figure 1 This is a scanning electron microscope image of the polyhydroxy fatty acid ester composition provided in Example 16 of the present invention.

[0091] Figure 2 This is a scanning electron microscope image of the polyhydroxy fatty acid ester composition provided in Example 18 of the present invention.

[0092] Figure 3 Scanning electron microscope (SEM) images of biodegradable plastic products provided in Embodiment 1-1 of the present invention.

[0093] Figure 4 This is a scanning electron microscope image of the biodegradable plastic product provided in Example 10-1 of the present invention. Detailed Implementation

[0094] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0095] All materials used in this invention can be purchased commercially or prepared using conventional methods. Unless otherwise specified, the materials used in this invention are as follows.

[0096] P3HB: Purchased from Beijing Microstructure Workshop Biotechnology Co., Ltd. PB3000.

[0097] Random P34HB-1: The mass percentage of 4HB structural units was 30%, purchased from Beijing Microstructure Factory Biotechnology Co., Ltd. PB3460.

[0098] Block P34HB-1: The mass percentage of 4HB structural units was 15%, purchased from Beijing Microstructure Workshop Biotechnology Co., Ltd. PB3430.

[0099] Epoxy chain extenders: ADR4370S, ADR4468.

[0100] Compatibilizer: BT-585 from Nanjing Baitong.

[0101] Toughening agent: DuPont's PTW.

[0102] Example 1

[0103] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 65.2 parts of poly-3-hydroxybutyrate (purchased from Beijing Microstructure Workshop Biotechnology Co., Ltd. PB3000), 15 parts of random P34HB-1 (4HB structural unit mass percentage of 30%, purchased from Beijing Microstructure Workshop Biotechnology Co., Ltd. PB3460), 15 parts of talc (2000 mesh), 1 part of boron nitride, 1 part of epoxy chain extender (ADR4468), 1 part of compatibilizer BT-585 (purchased from Nanjing Baitong), 0.5 parts of antioxidant 1010, 0.3 parts of EBS, and 1 part of toughening agent (DuPont PTW).

[0104] This embodiment provides a method for preparing a polyhydroxyalkanoate composition, specifically including the following steps: Poly(3-hydroxybutyrate), random P34HB-1, talc, boron nitride, chain extender, compatibilizer, EBS, antioxidant 1010, and toughening agent are uniformly dispersed in a high-speed mixer at 1000 rpm to obtain a mixture. The mixture is then added to a twin-screw extruder, subjected to plasticizing, vacuuming, extrusion, cooling, forced-air drying, cutting, particle screening in a vibrating screen with air blowing, dehumidification and drying, and finally weighing and packaging to obtain the polyhydroxyalkanoate composition particles. The parameters of the twin-screw extruder are: feed temperature zone: 100-110℃; equilibrium temperature zone: 115-125℃; discharge temperature zone: 125-140℃; screw speed: 100-200 rpm; vacuum zone: vacuum degree controlled at 0.6~0.8. MPa; Extrusion section temperature: 260℃; Circulating cooling water cooling; Three-stage blower drying method; Pelletizer speed: 800~900r / min.

[0105] Example 2

[0106] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 51.2 parts of poly-3-hydroxybutyrate, 15 parts of random P34HB-1 (4HB structural unit mass percentage of 30%), 15 parts of block P34HB-1 (4HB structural unit mass percentage of 15%, purchased from Beijing Microstructure Factory Biotechnology Co., Ltd. PB3430), 15 parts of magnesium silicate (2000 mesh), 1 part of boron nitride, 1 part of epoxy chain extender (ADR4468), 1 part of compatibilizer BT-585, 0.5 parts of antioxidant 1010, and 0.3 parts of EBS.

[0107] This embodiment provides a method for preparing a polyhydroxy fatty acid ester composition, and the specific steps are the same as in Example 1.

[0108] Example 3

[0109] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 50.2 parts of poly-3-hydroxybutyrate, 15 parts of random P34HB-1 (30% by mass of 4HB structural units), 15 parts of block P34HB-1 (15% by mass of 4HB structural units), 15 parts of calcined kaolin (5000 mesh), 1 part of boron nitride, 1 part of epoxy chain extender (ADR4468), 1 part of compatibilizer BT-585, 0.5 parts of antioxidant 1010, 0.3 parts of EBS, and 1 part of PTW (purchased from DuPont).

[0110] This embodiment provides a method for preparing a polyhydroxy fatty acid ester composition, and the specific steps are the same as in Example 1.

[0111] Example 4

[0112] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 50 parts of poly-3-hydroxybutyrate, 15 parts of random P34HB-1 (4HB structural unit mass percentage of 30%), 15 parts of block P34HB-1 (4HB structural unit mass percentage of 15%), 15 parts of calcined kaolin (5000 mesh), 1 part of boron nitride, 1 part of epoxy chain extender (ADR4468), 1 part of compatibilizer BT-585, 0.5 parts of antioxidant 1010, 0.5 parts of stearic acid, and 1 part of PTW.

[0113] This embodiment provides a method for preparing a polyhydroxy fatty acid ester composition, and the specific steps are the same as in Example 1.

[0114] Example 5

[0115] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 51 parts of poly-3-hydroxybutyrate, 15 parts of random P34HB-1 (4HB structural unit mass percentage of 30%), 15 parts of block P34HB-1 (4HB structural unit mass percentage of 15%), 15 parts of magnesium silicate (5000 mesh), 0.5 parts of titanium dioxide, 1 part of epoxy chain extender (ADR4468), 1 part of compatibilizer BT-585, 0.5 parts of stearic acid, and 1 part of PTW.

[0116] This embodiment provides a method for preparing a polyhydroxy fatty acid ester composition, and the specific steps are the same as in Example 1.

[0117] Example 6

[0118] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 1 in that talc is replaced with an equal mass of magnesium silicate, while the other components, amounts, and preparation methods are the same as in Example 1.

[0119] Example 7

[0120] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 6 in that the mass of random P34HB-1 is 17 parts, no toughening agent is used, the mass of poly-3-hydroxybutyrate is 64.2 parts, and the other components, amounts, and preparation methods are the same as in Example 1.

[0121] Example 8

[0122] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 7 in that the mass of random P34HB-1 is 20 parts, the mass of poly-3-hydroxybutyrate is 61.2 parts, and the other components, amounts, and preparation methods are the same as in Example 1.

[0123] Example 9

[0124] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 8 in that the mass of magnesium silicate is 10 parts, the mass of poly3-hydroxybutyrate is 66.2 parts, and the other components, amounts, and preparation methods are the same as in Example 1.

[0125] Example 10

[0126] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 52 parts of poly-3-hydroxybutyrate, 15 parts of random P34HB-1 (4HB structural unit mass percentage of 30%), 15 parts of block P34HB-1 (4HB structural unit mass percentage of 15%), 10 parts of calcined kaolin (5000 mesh), 5 parts of magnesium silicate (5000 mesh), 0.5 parts of titanium dioxide, 1 part of epoxy chain extender (ADR4468), 1 part of compatibilizer BT-585, and 0.5 parts of stearic acid.

[0127] This embodiment provides a method for preparing a polyhydroxy fatty acid ester composition, and the specific steps are the same as in Example 1.

[0128] Example 11

[0129] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 5 in that magnesium silicate is replaced with an equal mass of calcined kaolin (5000 mesh), while the other components, dosages, and preparation methods are the same as in Example 5.

[0130] Example 12

[0131] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 56.5 parts of poly-3-hydroxybutyrate, 20 parts of random P34HB-1 (4HB structural unit mass percentage of 30%), 10 parts of block P34HB-1 (4HB structural unit mass percentage of 15%), 8 parts of magnesium silicate (2000 mesh), 2 parts of boron nitride, 2 parts of epoxy chain extender (ADR4468), 0.5 parts of compatibilizer BT-585, 0.2 parts of antioxidant 1010, and 0.8 parts of EBS.

[0132] This embodiment provides a method for preparing a polyhydroxy fatty acid ester composition, and the specific steps are the same as in Example 1.

[0133] Example 13

[0134] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 2 in that the mass of random P34HB-1 is 3 parts, the mass of block P34HB-1 is 27 parts, and the other components, amounts, and preparation methods are the same as in Example 2.

[0135] Example 14

[0136] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 2 in that the mass of random P34HB-1 is 25 parts, the mass of block P34HB-1 is 5 parts, and the other components, amounts, and preparation methods are the same as in Example 2.

[0137] Example 15

[0138] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 2 in that the mass percentage of 4HB in random P34HB is 20%, and the mass percentage of 4HB in block P34HB is 25%. Other components, dosages, and preparation methods are the same as in Example 2.

[0139] Example 16

[0140] This embodiment provides a polyhydroxyalkanoate composition, which, based on a total weight of 100 parts, comprises 51 parts of poly-3-hydroxybutyrate, 15 parts of random P34HB-1, 15 parts of block P34HB-1, 15 parts of calcined kaolin (4000 mesh), 0.5 parts of titanium dioxide, 1 part of epoxy chain extender ADR4468, 1 part of compatibilizer BT-585, 0.5 parts of stearic acid, and 1 part of toughening agent PTW.

[0141] This embodiment provides a method for preparing a polyhydroxy fatty acid ester composition, and the specific steps are the same as in Example 1.

[0142] The morphology of the obtained polyhydroxyalkanoate composition was tested using scanning electron microscopy, and the results are as follows: Figure 1 As shown; by Figure 1 It can be seen that the polyhydroxy fatty acid ester composition is well dispersed, has a regular morphology, and has no obvious agglomerated particles.

[0143] Example 17

[0144] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 16 in that the calcined kaolin has a mesh size of 500 mesh, while the other components, dosages, and preparation methods are the same as in Example 16.

[0145] Example 18

[0146] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 16 in that the calcined kaolin has a mesh size of 6000 mesh, while the other components, dosages, and preparation methods are the same as in Example 16.

[0147] The morphology of the obtained polyhydroxyalkanoate composition was tested using scanning electron microscopy, and the results are as follows: Figure 2 As shown; by Figure 2It is known that the polyhydroxy fatty acid ester composition has poor dispersion and obvious agglomerated particles.

[0148] Example 19

[0149] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 2 in that boron nitride is replaced with an equal mass of cyclohexyl phthalate, while the other components, amounts, and preparation methods are the same as in Example 2.

[0150] Example 20

[0151] This embodiment provides a polyhydroxy fatty acid ester composition, which differs from Example 2 in that the epoxy chain extender (ADR4468) is replaced with an equal mass of amino chain extender (ethylenediamine), while the other components, dosages, and preparation methods are the same as in Example 2.

[0152] Comparative Example 1

[0153] This comparative example provides a polyhydroxy fatty acid ester composition, which differs from Example 2 in that it does not contain random P34HB, the mass of poly-3-hydroxybutyrate is 66.2 parts, and the other components, amounts and preparation methods are the same as in Example 2.

[0154] Comparative Example 2

[0155] This comparative example provides a polyhydroxy fatty acid ester composition, which differs from Example 2 in that it does not contain poly-3-hydroxybutyrate, the mass of random P34HB is 40.6 parts, the mass of block P34HB is 40.6 parts, and the other components, amounts, and preparation methods are the same as in Example 2.

[0156] Application examples

[0157] This application example provides a straw, which is prepared using the polyhydroxyalkanoate composition provided in the examples and comparative examples. The specific preparation method of the straw includes: (1) adding the polyhydroxyalkanoate composition into a single screw extruder, melting and extruding it, and then traction molding it through a die to obtain a preform; wherein, the process parameters of the single screw extruder are: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of die 1 is 166.6℃; temperature of die 2 is 160.9℃; (2) subjecting the preform obtained in step (2) to a water bath at 49℃ for shaping, and then drying it at 80℃ for 4h to obtain the straw with a thickness of 0.15-0.30mm.

[0158] The obtained straws were subjected to the following performance tests.

[0159] (1) Weight average molecular weight Mw: Tested using gel permeation chromatography.

[0160] (2) Melt Flow Index (MFI): Test standard: GB / T 3682.1-2018.

[0161] (3) Toughness: The straws prepared from the polyhydroxyalkanoate compositions provided in the examples and comparative examples were frozen in a -20°C freezer for 25-30 minutes and then taken out. The straws were flattened from one end to the other while being bent at 90°. The straw breakage was observed. Wherein, a indicates no breakage; b indicates a small crack (the broken part is less than one-third of the straw length); c indicates a large crack (the broken part is greater than or equal to one-third of the straw length). 10 straws were used as a group, and the breakage of the straws in the group was recorded. For example, 7a2b2c indicates that 7 out of 10 straws had no breakage, 2 had small cracks, and 2 had large cracks. "×" indicates that the straws were difficult to form and could not be tested.

[0162] (4) Migration amount: The test sample is placed in ethanol or acetic acid, immersed, and placed at 40°C for 2 hours. The migration amount is calculated. For details, refer to GB 31604.1 National Food Safety Standard General Rules for Migration Test of Food Contact Materials and Articles.

[0163] The specific test results are shown in Table 1.

[0164] Table 1

[0165]

[0166] As shown in Table 1, the straw material prepared from the polyhydroxyalkanoate composition provided by this invention has a melt index ≥0.96 g / 10min at 190℃ and 2.16 kg, and can even reach above 2.16 g / 10min; after freezing at -20℃, the proportion of straws without breakage or with small cracks is ≥50%, and can even reach above 80%, and the migration amount in ethanol (40℃, 2h) is ≤7.58 mg / dm³. 2 The migration amount in acetic acid (40℃, 2h) is ≤10 mg / dm³. 2 As can be seen, the polyhydroxy fatty acid ester composition provided by the present invention uses a copolymer of a specific type of 3-hydroxybutyrate and 4-hydroxybutyrate to prepare a material with better mechanical properties, processing properties and migration resistance.

[0167] As can be seen from Examples 1 and 2-5, the use of block P34HB and random P34HB composites is beneficial to further improve the toughness of the material.

[0168] As can be seen from Examples 7, 8, and 9, when the content of the random P34HB is within a specific range, the prepared material has higher toughness.

[0169] A comparison of Examples 1-5 with Example 10 shows that using a single inorganic filler is beneficial for further improving the toughness of the material.

[0170] As can be seen from Examples 2 and 13 and 14, using a specific ratio of random P34HB and block P34HB can balance the toughness and molding performance of the material. If the content of random P34HB is too low and the content of block P34HB is too high, the toughness is poor. If the content of random P34HB is too high and the content of block P34HB is too low, the crystallization effect is poor, which affects molding and processing and makes it difficult to mold.

[0171] As can be seen from Examples 2 and 15, using random P34HB and block P34HB with specific 4HB content is beneficial to further improve the molding and processing performance and migration resistance of the material.

[0172] As can be seen from Examples 16, 17, and 18, if inorganic fillers of a specific mesh size are not used, the apparent properties or molding and processing properties of the material will deteriorate. If the mesh size is too low, the material surface will be rough and pitted, resulting in substandard product quality. If the mesh size is too high, the crystallization effect will be poor, making it difficult to shape. Furthermore, it is prone to agglomeration and the formation of infusible particles, which will affect the processing performance.

[0173] As can be seen from Examples 2 and 19 and 20, the molding and processing performance of the material deteriorates when no specific type of nucleating agent and chain extender is used.

[0174] As can be seen from Comparative Examples 1 and 2, the absence of random P34HB or poly-3-hydroxybutyrate in the composition results in a decrease in the toughness, molding and processing properties, or migration resistance of the material.

[0175] Example 1-1

[0176] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) 51 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of calcined kaolin (4000 mesh), 0.5 parts by weight of titanium dioxide, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.5 parts by weight of stearic acid and 1 part of toughening agent are mixed in a high-speed mixer at a speed of 200 rpm to obtain a mixture; the mixture is then... The compound is added to a twin-screw extruder, and after plasticizing, vacuuming, extrusion, cooling, drying with forced air, cutting, screening into particles in a vibrating screen with blowing air, and dehumidifying and drying, polyhydroxyalkanoate particles are obtained. The process parameters of the twin-screw extruder are as follows: screw diameter 65mm; temperature of the first temperature zone 105-110℃ (the first temperature zone includes zones 1, 2, and 3, with temperatures of 105℃, 105℃, and 110℃ respectively); temperature of the second temperature zone 120-130℃ (the second temperature zone includes zones 4, 5, and 6, with temperatures of 105℃, 105℃, and 110℃ respectively). The temperatures in the first three zones are 120℃, 120℃, and 130℃ respectively; the temperature in the third zone is 130-135℃ (the third zone includes zones 7, 8, and 9, with temperatures of 130℃, 135℃, and 135℃ respectively); the mold temperature is 145℃, the melt temperature is 149℃, the screw speed is 120rpm, the feed speed is 39rpm, and the vacuum degree is -0.6bar; (2) The polyhydroxy fatty acid ester particles obtained in step (1) are added to a single-screw extruder, melt-extruded, and shaped by die traction to obtain a preform. ; The process parameters of the single screw extruder are: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) The preform obtained in step (2) is subjected to water bath shaping treatment at 49℃, and after air drying and slitting steps, the slitting product is placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic product.

[0177] The morphology of the biodegradable plastic products obtained in Examples 1-1 was characterized using scanning electron microscopy, and the results are as follows: Figure 3 As shown; by Figure 3 It can be seen that the biodegradable plastic products are well dispersed, have regular morphology, and have no obvious agglomerated particles.

[0178] Example 2-1

[0179] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the mixture includes 69 parts by weight of P3HB, 10 parts by weight of random P34HB-1, 10 parts by weight of block P34HB-1, 5 parts by weight of calcined kaolin, 1 part by weight of titanium dioxide, 2 parts by weight of epoxy chain extender, 2 parts by weight of compatibilizer, 0.3 parts by weight of stearic acid and 0.7 parts by weight of toughening agent; other steps and parameters are the same as in Embodiment 1-1.

[0180] Example 3-1

[0181] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the mixture includes 61 parts by weight of P3HB, 5 parts by weight of random P34HB-1, 6 parts by weight of block P34HB-1, 18 parts by weight of calcined kaolin, 3 parts by weight of titanium dioxide, 0.5 parts by weight of epoxy chain extender, 3 parts by weight of compatibilizer, 1.5 parts by weight of stearic acid and 2 parts by toughening agent; other steps and parameters are the same as in Embodiment 1-1.

[0182] Example 4-1

[0183] This embodiment provides a biodegradable plastic product, which differs from Example 1 in that, in the preparation method, in step (1), the mixture does not contain block P34HB-1, the content of P3HB is 66 parts by weight, and the other steps and parameters are the same as in Example 1-1.

[0184] Example 5-1

[0185] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the mixture does not contain block P34HB-1, the content of random P34HB is 20 parts, and the content of P3HB is 61 parts by weight. Other steps and parameters are the same as in Embodiment 1-1.

[0186] Example 6-1

[0187] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the content of random P34HB-1 in the mixture is 5 parts and the content of block P34HB-1 is 25 parts, and the other steps and parameters are the same as in Embodiment 1-1.

[0188] Example 7-1

[0189] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the calcined kaolin in the mixture is replaced with talc powder of the same mesh size and weight, and the other steps and parameters are the same as in Embodiment 1-1.

[0190] Example 8-1

[0191] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the calcined kaolin in the mixture is replaced with magnesium silicate of the same mesh size and weight, while the other steps and parameters are the same as in Embodiment 1-1.

[0192] Example 9-1

[0193] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the calcined kaolin in the mixture has a mesh size of 500 mesh, and the other steps and parameters are the same as in Embodiment 1-1.

[0194] Example 10-1

[0195] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the calcined kaolin in the mixture has a mesh size of 6000 mesh, and the other steps and parameters are the same as in Embodiment 1-1.

[0196] The morphology of the biodegradable plastic products obtained in Example 10-1 was characterized using scanning electron microscopy, and the results are as follows: Figure 4 As shown; by Figure 4 It can be seen that the biodegradable plastic products have poor dispersion and obvious agglomerated particles.

[0197] Example 11-1

[0198] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), titanium dioxide is replaced with an equal mass of cyclohexyl phthalate in the mixture, and the other steps and parameters are the same as in Embodiment 1-1.

[0199] Example 12-1

[0200] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that, in the preparation method, in step (1), the epoxy chain extender in the mixture is replaced with an equal mass of ethylenediamine, and the other steps and parameters are the same as in Embodiment 1-1.

[0201] Example 13-1

[0202] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) 51.2 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of magnesium silicate (2000 mesh), 1 part by weight of boron nitride, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.5 parts by weight of antioxidant 1010 and 0.3 parts by weight of lubricant EBS are mixed in a high-speed mixer at a speed of 300 rpm to obtain a mixture. The mixture is added to a twin-screw extruder, and subjected to plasticizing, vacuuming, extrusion, cooling, drying with forced air, cutting, granulation screening in a vibrating screen with blowing air, dehumidification and drying to obtain polyhydroxyalkanoate particles; wherein, the process parameters of the twin-screw extruder are: screw diameter 65mm; temperature of the first temperature zone 100-110℃ (the first temperature zone includes zones 1, 2, and 3, with temperatures of 100℃, 100℃, and 110℃ respectively); temperature of the second temperature zone 115-120℃ (the second temperature zone includes zones 4, 5, and 6, with temperatures of 100℃, 100℃, and 110℃ respectively); and temperature of the second temperature zone 115-120℃ (the second temperature zone includes zones 4, 5, and 6, with temperatures of 100℃, 100℃, and 110℃ respectively). Zone 6, with temperatures of 115℃, 120℃, and 120℃ respectively; Zone 3, with temperatures of 125-128℃ (Zone 3 includes Zones 7, 8, and 9, with temperatures of 125℃, 125℃, and 128℃ respectively); Mold temperature is 130℃, melt temperature is 144℃, screw speed is 120rpm, feed speed is 40rpm, and vacuum degree is -0.6bar; (2) Add the polyhydroxy fatty acid ester particles obtained in step (1) to a single-screw extruder, melt extrude, and form by die traction to obtain a preform. The process parameters of the single screw extruder are as follows: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) the preform obtained in step (2) is subjected to water bath shaping treatment at 46℃, and after air drying and slitting steps, the slitting product is placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic product.

[0203] Example 14-1

[0204] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) 50.2 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of calcined kaolin (5000 mesh), 1 part by weight of boron nitride, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.5 parts by weight of antioxidant 1010, 0.3 parts by weight of lubricant EBS and 1 part of toughening agent are mixed in a high-speed mixer at a speed of 100 rpm. The mixture is then added to a twin-screw extruder, where it undergoes plasticizing, vacuuming, extrusion, cooling, forced-air drying, slitting, particle screening in a vibrating screen with air blowing, and dehumidification drying to obtain polyhydroxyalkanoate particles. The process parameters of the twin-screw extruder are as follows: screw diameter 65 mm; temperature of the first temperature zone 100-110℃ (the first temperature zone includes zones 1, 2, and 3, with temperatures of 100℃, 100℃, and 110℃ respectively); temperature of the second temperature zone 115-120℃ (the second temperature zone includes zone 4). Zones 5 and 6, with temperatures of 115℃, 120℃, and 120℃ respectively; the temperature of the third temperature zone is 125-128℃ (the third temperature zone includes zones 7, 8, and 9, with temperatures of 125℃, 125℃, and 128℃ respectively); the mold temperature is 130℃, the melt temperature is 146℃, the screw speed is 120rpm, the feed speed is 40rpm, and the vacuum degree is -0.6bar; (2) The polyhydroxy fatty acid ester particles obtained in step (1) are added to a single-screw extruder, melt-extruded, and shaped by die traction to obtain Preformed parts; wherein, the process parameters of the single screw extruder are: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) the preformed parts obtained in step (2) are subjected to water bath shaping treatment at 45℃, and after air drying and slitting steps, the slitting products are placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic products.

[0205] Example 15-1

[0206] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) mixing 50.2 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of calcined kaolin (5000 mesh), 1 part by weight of boron nitride, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.5 parts by weight of antioxidant 1010, 0.3 parts by weight of lubricant EBS and 1 part by weight of toughening agent in a high-speed mixer at a speed of 200 rpm to obtain... The mixture is added to a twin-screw extruder, and then subjected to plasticizing, vacuuming, extrusion, cooling, drying with forced air, slitting, granulation screening in a vibrating screen with blowing air, dehumidification and drying to obtain polyhydroxyalkanoate particles; wherein the process parameters of the twin-screw extruder are: screw diameter 75mm; temperature of the first temperature zone 95℃ (the first temperature zone includes zones 1, 2 and 3, all with a temperature of 95℃); temperature of the second temperature zone 1000℃ (the second temperature zone includes zones 4, 5 and 6, all with a temperature of 100℃); temperature of the third temperature zone 100-100℃. 5℃ (the third temperature zone includes zones 7, 8, and 9, with temperatures of 100℃, 100℃, and 105℃ respectively); the temperature of the fourth temperature zone is 110-125℃ (the third temperature zone includes zones 10, 11, and 12, with temperatures of 110℃, 115℃, and 125℃ respectively); the mold temperature is 135℃, the melt temperature is 124℃, the screw speed is 140rpm, the feed speed is 6rpm, and the vacuum degree is -0.5bar; (2) the polyhydroxy fatty acid ester particles obtained in step (1) are added to a single-screw extruder, melt-extruded, and drawn through the mold. The preform is obtained by drawing and forming; wherein, the process parameters of the single screw extruder are: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) the preform obtained in step (2) is subjected to water bath shaping treatment at 45℃, and after air drying and slitting steps, the slitting product is placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic product.

[0207] Example 16-1

[0208] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) 50.2 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of calcined kaolin (5000 mesh), 1 part by weight of boron nitride, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.5 parts by weight of antioxidant 1010, 0.3 parts by weight of lubricant stearic acid and 1 part by weight of toughening agent are mixed in a high-speed mixer at 200 rpm. Rapid mixing yields a mixture; the mixture is then added to a twin-screw extruder, where it undergoes plasticizing, vacuuming, extrusion, cooling, forced-air drying, slitting, particle screening in a vibrating screen with blowing air, dehumidification, and drying to obtain polyhydroxyalkanoate particles; wherein the process parameters of the twin-screw extruder are: screw diameter 65mm; temperature of the first temperature zone 100-110℃ (the first temperature zone includes zones 1, 2, and 3, with temperatures of 100℃, 100℃, and 110℃ respectively); temperature of the second temperature zone 115-120℃ (the second temperature zone includes zones 4... Zones 1, 5, and 6, with temperatures of 115℃, 120℃, and 120℃ respectively; the temperature of the third temperature zone is 125-128℃ (the third temperature zone includes zones 7, 8, and 9, with temperatures of 125℃, 125℃, and 128℃ respectively); the mold temperature is 130℃, the melt temperature is 144℃, the screw speed is 120rpm, the feed speed is 40rpm, and the vacuum degree is -0.5bar; (2) The polyhydroxy fatty acid ester particles obtained in step (1) are added to a single-screw extruder, melt-extruded, and shaped by die traction to obtain Preformed parts; wherein, the process parameters of the single screw extruder are: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) the preformed parts obtained in step (2) are subjected to water bath shaping treatment at 45℃, and after air drying and slitting steps, the slitting products are placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic products.

[0209] Example 17-1

[0210] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) 50.2 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of calcined kaolin (5000 mesh), 1 part by weight of boron nitride, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.5 parts by weight of antioxidant 1010, 0.3 parts by weight of lubricant stearic acid and 1 part by weight of toughening agent are mixed in a high-speed mixer at 200 rpm. Rapid mixing yields a mixture; the mixture is then added to a twin-screw extruder, where it undergoes plasticizing, vacuuming, extrusion, cooling, forced-air drying, slitting, particle screening in a vibrating screen with blowing air, dehumidification and drying to obtain polyhydroxyalkanoate particles; wherein the process parameters of the twin-screw extruder are: screw diameter 65mm; temperature of the first temperature zone 100-110℃ (the first temperature zone includes zones 1, 2, and 3, with temperatures of 100℃, 100℃, and 110℃ respectively); temperature of the second temperature zone 115-125℃ (the second temperature zone includes zones 4... Zones 1, 5, and 6, with temperatures of 115℃, 125℃, and 125℃ respectively; the temperature of the third temperature zone is 125-130℃ (the third temperature zone includes zones 7, 8, and 9, with temperatures of 125℃, 130℃, and 130℃ respectively); the mold temperature is 135℃, the melt temperature is 150℃, the screw speed is 120rpm, the feed speed is 40rpm, and the vacuum degree is -0.6bar; (2) The polyhydroxy fatty acid ester particles obtained in step (1) are added to a single-screw extruder, melt-extruded, and shaped by die traction to obtain Preformed parts; wherein, the process parameters of the single screw extruder are: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) the preformed parts obtained in step (2) are subjected to water bath shaping treatment at 45℃, and after air drying and slitting steps, the slitting products are placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic products.

[0211] Example 18-1

[0212] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) 51.0 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of magnesium silicate (5000 mesh), 0.5 parts by weight of titanium dioxide, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.3 parts by weight of lubricant stearic acid and 1 part by weight of toughening agent are mixed in a high speed mixer at a speed of 200 rpm to obtain a mixture; The mixture is added to a twin-screw extruder, and after plasticizing, vacuuming, extrusion, cooling, drying with forced air, slitting, screening into particles in a vibrating screen with blowing air, and dehumidifying and drying, polyhydroxyalkanoate particles are obtained. The process parameters of the twin-screw extruder are as follows: screw diameter 65 mm; temperature of the first temperature zone 105-110℃ (the first temperature zone includes zones 1, 2, and 3, with temperatures of 105℃, 105℃, and 110℃ respectively); temperature of the second temperature zone 120-130℃ (the second temperature zone includes zones 4, 5, and 6). The temperatures are 120℃, 130℃, and 130℃ respectively; the temperature of the third temperature zone is 130-135℃ (the third temperature zone includes zones 7, 8, and 9, with temperatures of 130℃, 135℃, and 135℃ respectively); the mold temperature is 145℃, the melt temperature is 149℃, the screw speed is 120rpm, the feed speed is 39rpm, and the vacuum degree is -0.6bar; (2) The polyhydroxy fatty acid ester particles obtained in step (1) are added to a single screw extruder, melt-extruded, and shaped by mold traction to obtain a preform. The process parameters of the single screw extruder are as follows: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) the preform obtained in step (2) is subjected to water bath shaping treatment at 45℃, and after air drying and slitting steps, the slitting product is placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic product.

[0213] Example 19-1

[0214] This embodiment provides a biodegradable plastic product. The preparation method of the biodegradable plastic product includes the following steps: (1) 51.0 parts by weight of P3HB, 15 parts by weight of random P34HB-1, 15 parts by weight of block P34HB-1, 15 parts by weight of magnesium silicate (5000 mesh), 0.5 parts by weight of titanium dioxide, 1 part by weight of epoxy chain extender, 1 part by weight of compatibilizer, 0.3 parts by weight of lubricant stearic acid and 1 part by weight of toughening agent are mixed in a high-speed mixer at a speed of 200 rpm to obtain a mixture; the mixture is added to a twin-screw extruder and plasticized. Vacuuming, extrusion, cooling, forced air drying, cutting, particle screening in a vibrating screen with blowing air, dehumidification and drying to obtain polyhydroxyalkanoate particles; both P3HB and block P34HB were washed with ethanol at 40℃ for 2 hours; the process parameters of the twin-screw extruder were: screw diameter 35mm; temperature of the first temperature zone 100-130℃ (the first temperature zone includes zones 1, 2, and 3, with temperatures of 100℃, 120℃, and 130℃ respectively); temperature of the second temperature zone 130-135℃ (the second temperature zone includes zones 4, 5, and 6, with temperatures of 100℃, 120℃, and 130℃ respectively); and temperature of the second temperature zone 130-135℃ (the second temperature zone includes zones 4, 5, and 6, with temperatures of 100℃, 120℃, and 130℃ respectively). The temperatures of the three temperature zones are 130℃, 135℃, and 135℃ respectively; the temperature of the third temperature zone is 140-145℃ (the third temperature zone includes zones 7, 8, and 9, with temperatures of 140℃, 145℃, and 145℃ respectively); the temperature of the fourth temperature zone is 145-150℃ (the fourth temperature zone includes zones 10 and 11, with temperatures of 145℃ and 150℃ respectively); the mold temperature is 150℃, the melt temperature is 149℃, the screw speed is 155rpm, the feed speed is 5rpm, and the vacuum degree is -0.6bar; (2) The polyhydroxy fatty acid ester particles obtained in step (1) are added to the single screw extruder. In the machine, melt extrusion is performed and shaped by the mold to obtain a preform; wherein, the process parameters of the single screw extruder are: screw diameter is 65mm; first temperature zone A1: 178℃; second temperature zone A2: 156℃; third temperature zone A3: 170℃; fourth temperature zone A4: 170℃; temperature of mold 1 is 166.6℃; temperature of mold 2 is 160.9℃; (3) the preform obtained in step (2) is subjected to water bath shaping treatment at 45℃, and after air drying and slitting steps, the slitting product is placed in an oven and dried at 80℃ for 4h to obtain the biodegradable plastic product.

[0215] Example 20-1

[0216] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that the temperature of the water bath in step (3) of the preparation method of the biodegradable plastic product is 47°C, and other parameters are the same as those in Embodiment 1-1.

[0217] Example 21-1

[0218] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that the temperature of the water bath in step (3) of the preparation method of the biodegradable plastic product is 55°C, and other parameters are the same as those in Embodiment 1-1.

[0219] Example 22-1

[0220] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that the process parameters of the single-screw extruder in step (2) of the preparation method are as follows: screw diameter is 65mm; first temperature zone A1: 190℃; second temperature zone A2: 170℃; third temperature zone A3: 190℃; fourth temperature zone A4: 190℃; temperature of mold 1 is 180.4℃; temperature of mold 2 is 180.8℃; other raw materials, dosages and preparation methods are the same as in Embodiment 1-1.

[0221] Example 23-1

[0222] This embodiment provides a biodegradable plastic product, which differs from Embodiment 1-1 in that the screw diameter in step (2) of the preparation method of the biodegradable plastic product is 50 mm, and other parameters are the same as those in Embodiment 1-1.

[0223] Example 24-1

[0224] This embodiment provides a biodegradable plastic product, which differs from Example 13-1 in that step (3) of the preparation method is not dried at 80°C for 4 hours; other raw materials, dosages and preparation methods are the same as in Example 13-1.

[0225] Comparative Example 1-1

[0226] This comparative example provides a biodegradable plastic product, which differs from Example 1-1 in that the mixture in step (1) of the preparation method of the biodegradable plastic product does not contain random block P34HB-1, the mass of block P34HB-1 is 30 parts by weight, and other parameters are the same as those in Example 1-1.

[0227] Comparative Example 2-1

[0228] This comparative example provides a biodegradable plastic product, which differs from Example 1-1 in that the preparation method of the biodegradable plastic product does not include step (3), in which the preform is directly cooled to room temperature in air. All other parameters are the same as in Example 1-1.

[0229] Performance testing

[0230] (1) Weight average molecular weight Mw: The Mw of polyhydroxyalkanoate particles was tested by gel permeation chromatography.

[0231] (2) Melt Flow Index (MFI): Test standard: GB / T 3682.1-2018; tests polyhydroxyalkanoate particles.

[0232] (3) Toughness: The products (thickness of 0.15-0.30 mm, straw products) provided in the examples and comparative examples were frozen in a -20℃ refrigerator for 25-30 minutes and then taken out. The straw was flattened from one end to the other while being bent at 90°. The straw breakage was observed. Wherein, a indicates no breakage; b indicates a small crack (the broken part is less than one-third of the straw length); c indicates a large crack (the broken part is greater than or equal to one-third of the straw length). 10 straws were used as a group, and the breakage of straws in a group was recorded. For example, 7a2b2c indicates that 7 out of 10 straws had no breakage, 2 had small cracks, and 2 had large cracks. "×" indicates that it is difficult to form and cannot be tested.

[0233] (4) Migration amount: The products provided in the examples and comparative examples were placed in ethanol or acetic acid, immersed, and placed at 40°C for 2 hours. The migration amount was calculated, and the specific reference was GB 31604.1 National Food Safety Standard General Rules for Migration Test of Food Contact Materials and Articles.

[0234] (5) Tablet odor: Select a group of 7 people aged 25-35 who do not smoke. Place the straw in a closed space and the group will conduct the test. The group members will smell the sample and score it according to their personal feelings. The average score is taken. The scoring level includes 1-5 points, where 1 point is unbearable, 2 points is relatively unbearable, 3 points is acceptable, 4 points is almost unsmelly, and 5 points is unsmelly.

[0235] The specific test results are shown in Table 2.

[0236] Table 2

[0237]

[0238] As shown in Table 2, the biodegradable plastic products provided by the present invention, by using a specific formula and a specific process, have excellent toughness, low migration, good processing and molding performance, and low odor.

[0239] As can be seen from Examples 1-1 and 4-1 to 6-1, the use of block P34HB and random P34HB in combination is beneficial to further improve the toughness of the material; when there is no block P34HB or the content of random P34HB is too high, the toughness of the product is poor and / or the molding and processing performance is poor.

[0240] As can be seen from Examples 1-1, 7-1, and 8-1, using specific types of inorganic fillers is beneficial to further improve the toughness and processing performance of materials.

[0241] As can be seen from Examples 1-1 and 9-1 and 10-1, if inorganic fillers of a specific mesh size are not used, the appearance or molding and processing performance of the product will deteriorate. If the mesh size is too low, the material surface will be rough and pitted, and the product quality will be unqualified. If the mesh size is too high, the crystallization effect will be poor and it will be difficult to shape. In addition, it is easy to agglomerate and generate infusible particles, which will affect the processing performance.

[0242] As can be seen from Examples 1-1, 11-1, and 12-1, the molding and processing performance of the material deteriorates when no specific type of nucleating agent and chain extender is used.

[0243] Comparing Examples 14-1 and 15-1, it can be seen that using an extruder with a specific screw diameter is beneficial to improving the molding and processing performance of the product.

[0244] Comparing Examples 16-1 and 17-1, it can be seen that using a specific molding temperature is beneficial to improving the appearance quality of the product.

[0245] As can be seen from Examples 1-1, 20-1, 21-1 and Comparative Example 2-1, washing with water and controlling the washing temperature within a specific range can help to further improve the toughness of the product and reduce odor.

[0246] As can be seen from Comparative Example 1-1, the product formulation does not contain random P34HB, resulting in poor toughness and / or molding performance.

[0247] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A polyhydroxyalkanoate composition, characterized in that, The polyhydroxy fatty acid ester composition includes poly(3-hydroxybutyrate) and at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate; The at least two 3-hydroxybutyrate and 4-hydroxybutyrate copolymers include block copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of at least one 4-hydroxybutyrate structural unit of ≥10% and ≤20%. The at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate include at least one random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate; The mass percentage of 3-hydroxybutyrate and 4-hydroxybutyrate block copolymer in the polyhydroxy fatty acid ester composition is ≥10% and ≤20%; The random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate contains 15-31% by mass of 4-hydroxybutyrate structural units. The mass percentage of the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate in the polyhydroxy fatty acid ester composition is 9-30%. The polyhydroxy fatty acid ester composition also includes inorganic fillers, nucleating agents, and chain extenders; The inorganic filler and nucleating agent each independently include any one or more combinations of talc, calcined kaolin, magnesium silicate, titanium dioxide, boron nitride, borax, bentonite, magnesium oxide, manganese oxide, nepheline syenite, zinc oxide, iron oxide, carbon black, glass wool, glass fiber, feldspar, tin dioxide, sodium magnesium aluminosilicate, calcium silicate, calcium aluminum silicate, diatomite, zinc phosphate, magnesia carbide, calcium sulfate, sodium sulfite, sodium bisulfite, calcite, magnesium iron tetroxide, silicon carbide, mica, wollastonite, calcium carbonate, silicon dioxide, aluminum oxide, barium sulfate, or montmorillonite. The inorganic filler has a mesh size of 1000~5000 mesh; The chain extender includes epoxy chain extenders.

2. The polyhydroxyalkanoate composition according to claim 1, characterized in that, Based on weight, the total mass of poly(3-hydroxybutyrate) and at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate in the polyhydroxy fatty acid ester composition is 35-99.9 parts, and the total mass of inorganic filler and nucleating agent is 9-25 parts.

3. The polyhydroxyalkanoate composition according to claim 1, characterized in that, The chain extender in the polyhydroxyalkanoate composition is 0.1 to 4 parts by weight.

4. The polyhydroxyalkanoate composition according to claim 1, characterized in that, Based on parts by weight, the polyhydroxyalkanoate composition further includes at least one of the following: 0.2 to 10 parts compatibilizer, 0.1 to 5 parts antioxidant, 0.1 to 5 parts lubricant, and 0.5 to 5 parts toughening agent; The weight-average molecular weight of the polyhydroxy fatty acid ester composition is 200,000 to 600,000. At 190°C and 2.16 kg, the melt index of the polyhydroxyalkanoate composition is 1-10 g / 10 min.

5. A method for preparing a polyhydroxyalkanoate composition according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: The poly(hydroxybutyrate) composition is obtained by mixing poly(3-hydroxybutyrate), at least two copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate, inorganic filler, nucleating agent, chain extender, melting and extruding.

6. The preparation method according to claim 5, characterized in that, The mixed material also includes at least one of a compatibilizer, antioxidant, lubricant, or toughening agent; The melting temperature is 60~200℃; The extrusion temperature is 60~200℃.

7. A biodegradable product, characterized in that, The biodegradable product is prepared using the polyhydroxyalkanoate composition according to any one of claims 1 to 4.

8. The biodegradable product according to claim 7, characterized in that, The shape of the biodegradable product includes at least one of hollow and membrane-like structures; The molding method of the biodegradable product includes one or more combinations of injection molding, compression molding, extrusion molding, biaxial stretching molding, and uniaxial stretching molding.

9. The biodegradable product according to claim 8, characterized in that, The hollow shape includes a tubular shape.

10. The biodegradable product according to claim 8, characterized in that, The extrusion molding includes extrusion blow molding.

11. A biodegradable plastic product, characterized in that, The biodegradable plastic product is prepared by the following method, the method comprising: (1) Mix poly(3-hydroxybutyrate), copolymers of at least two types of 3-hydroxybutyrate and 4-hydroxybutyrate, inorganic filler, nucleating agent, chain extender, melt, extrude and granulate to obtain polyhydroxy fatty acid ester particles; The at least two 3-hydroxybutyrate and 4-hydroxybutyrate copolymers include block copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate with a mass percentage of at least one 4-hydroxybutyrate structural unit of ≥10% and ≤20%. The copolymers of at least two 3-hydroxybutyrates and 4-hydroxybutyrates include at least one random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate; the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate contains 15-31% by mass of 4-hydroxybutyrate structural units. The polyhydroxy fatty acid ester particles contain ≥10% and ≤20% by mass of 3-hydroxybutyrate and 4-hydroxybutyrate block copolymers, with a mass percentage of 4-hydroxybutyrate structural units of ≥10% and ≤20%; In step (1), the mass percentage of the random copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate in the polyhydroxy fatty acid ester particles is 9-30%. The inorganic filler and nucleating agent each independently include any one or more combinations of talc, calcined kaolin, magnesium silicate, titanium dioxide, boron nitride, borax, bentonite, magnesium oxide, manganese oxide, nepheline syenite, zinc oxide, iron oxide, carbon black, glass wool, glass fiber, feldspar, tin dioxide, sodium magnesium aluminosilicate, calcium silicate, calcium aluminum silicate, diatomite, zinc phosphate, magnesia carbide, calcium sulfate, sodium sulfite, sodium bisulfite, calcite, magnesium iron tetroxide, silicon carbide, mica, wollastonite, calcium carbonate, silicon dioxide, aluminum oxide, barium sulfate, or montmorillonite. The inorganic filler has a mesh size of 1000~5000 mesh; The chain extender includes epoxy chain extenders; The diameter of the screw used in the extrusion in step (1) is 60~70mm; (2) The polyhydroxyalkanoate particles described in step (1) are molded to obtain a preform; The diameter of the screw used in step (2) is 60~70mm; The molding temperature in step (2) is 100~185℃; (3) The preform described in step (2) is post-processed to obtain the biodegradable plastic product; The post-processing in step (3) includes water bath shaping of the preform.

12. The biodegradable plastic product according to claim 11, characterized in that, Based on weight, the total mass of poly(3-hydroxybutyrate) and copolymers of at least two types of 3-hydroxybutyrate and 4-hydroxybutyrate in the polyhydroxy fatty acid ester particles is 35 to 99.9 parts, and the total mass of inorganic fillers and nucleating agents is 9 to 25 parts.

13. The biodegradable plastic product according to claim 11, characterized in that, By weight, the chain extender in the polyhydroxy fatty acid ester particles in step (1) is 0.1 to 4 parts; By weight, the polyhydroxyalkanoate particles in step (1) further include at least one of the following: 0.2 to 10 parts compatibilizer, 0.1 to 5 parts antioxidant, 0.1 to 5 parts lubricant, and 0.5 to 5 parts toughening agent.

14. The biodegradable plastic product according to claim 11, characterized in that, The weight-average molecular weight of the polyhydroxyalkanoate particles in step (1) is 200,000 to 600,000. At 190℃ and 2.16kg, the melt index of the polyhydroxy fatty acid ester particles in step (1) is 1~10g / 10min.

15. The biodegradable plastic product according to claim 11, characterized in that, The melting temperature in step (1) is 60~200℃; The extrusion temperature in step (1) is 60~200℃; The extrusion in step (1) includes extrusion through the first temperature zone, the second temperature zone, the third temperature zone, and temperature zone A in sequence; The temperature of the first temperature zone is 90~130℃, the temperature of the second temperature zone is 100~135℃, the temperature of the third temperature zone is 100~145℃, and the temperature of temperature zone A is 130~150℃. Between the third temperature zone and temperature zone A, there is also a fourth temperature zone, the temperature of which is 110~150℃; The extrusion speed in step (1) is 100~400 rpm.

16. The biodegradable plastic product according to claim 11, characterized in that, The molding method described in step (2) includes at least one of injection molding, compression molding, extrusion molding, vacuum forming, casting, biaxial stretching molding, uniaxial stretching molding, injection stretch blow molding, and injection blow molding.

17. The biodegradable plastic product according to claim 16, characterized in that, The extrusion molding includes extrusion blow molding.

18. The biodegradable plastic product according to claim 11, characterized in that, The molding process includes sequentially performing a first stage, a second stage, a third stage, and a fourth stage. The temperature in the first stage is 158~180℃, the temperature in the second stage is 136~176℃, the temperature in the third stage is 150~185℃, and the temperature in the fourth stage is 150~185℃.

19. The biodegradable plastic product according to claim 11, characterized in that, The temperature of the water bath is 45~60℃; The water bath shaping process also includes a drying step; The drying temperature is 60~100℃, and the time is 1~10h.

20. The application of a biodegradable plastic product according to any one of claims 11 to 19 in tableware and packaging materials.

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