Molded body and preparation method therefor

Abstract

The present invention relates to the technical field of processing and modification of degradable materials, and in particular relates to a preparation method for a molded body and the use thereof. The preparation method comprises melting a raw material comprising a high molar amount of 4HB, then granulating same to obtain granules, and then heating the granules and then performing isothermal annealing molding. By simultaneously optimizing the process and material components, the problem of trimmings is comprehensively ameliorated, and the mechanical properties (such as impact strength) and heat resistance of the product are improved.

Description

A molded body and a preparation method thereof Technical Field

[0001] The present invention relates to the technical field of processing and modification of degradable materials, and in particular to a formed body and a preparation method thereof. Background Art

[0002] Polyhydroxyalkanoates (PHA) are a general term for high-molecular-weight polyesters produced by microbial fermentation using a variety of carbon sources. To date, more than 150 types of PHA have been reported, and they can be degraded in home compost, industrial compost, soil (environment), and marine environments. Due to their excellent biocompatibility, biodegradability, low carbon emissions, high barrier properties, and thermal processability, they have been widely used in packaging, textiles, agriculture, and biomedical materials. For example:

[0003] Patent CN1089564A discloses a compostable cardboard container and packaging for liquids that is coated with a material that degrades into carbon dioxide, water, and biomass under composting conditions. The coating material includes poly-3-hydroxybutyric acid and / or poly-3-hydroxyvaleric acid.

[0004] Patent CN115627057A discloses a straw and its production method. The straw is made from PHA, fillers, and additives. The straw exhibits excellent performance and rapidly and completely degrades in natural environments, remaining environmentally friendly throughout its lifecycle. This reduces environmental pollution caused by disposable plastics and reduces petroleum consumption.

[0005] However, pure PHA also has many defects, such as poor thermal stability, narrow thermal processing window, large spherulite size, low crystallization rate, and post-crystallization phenomenon, which lead to severe thermal decomposition of PHA, poor melt strength, poor toughness, embrittlement, slow curing and difficulty in cutting.

[0006] In this regard, patent JP2014227543A discloses a polyester resin composition containing polyhydroxyalkanoate and low-melting-point polyhydroxybutyrate, which can improve the crystallization rate of polyhydroxyalkanoate. However, the generation of flash during injection molding has not been solved. Furthermore, patent CN116194269A discloses a resin composition for injection molding and an injection-molded body. By adjusting the molar ratio of 3-hydroxybutyrate units to a range of 92-99%, not only can the flash be solved, but also the material can be processed at high temperatures. However, the overall mechanical properties of the material have not been well improved.

[0007] Summary of the Invention

[0008] To solve the problems of the prior art, the present invention provides a method for simultaneously optimizing the process and material components, comprehensively improving the flash problem, and improving the mechanical properties (such as impact strength) and heat resistance of the product. The improved toughness makes the injection molded product more moldable. Specifically:

[0009] The present invention provides a method for preparing a molded body. The method comprises the steps of melting raw materials and then granulating the raw materials to obtain pellets, and then heating the pellets and performing isothermal annealing to form the pellets.

[0010] The raw materials include two or more polyhydroxyalkanoates blended together.

[0011] Preferably, two, three, four, five, six, seven, eight, nine or ten or more polyhydroxyalkanoates are blended.

[0012] The polyhydroxyalkanoate comprises a homopolymer or copolymer of monomers constituting the polyhydroxyalkanoate. The monomers constituting the polyhydroxyalkanoate include, but are not limited to, one or a combination of two or more of 2-hydroxypropionic acid, 3-hydroxypropionic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxypentanoic acid, 5-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, or 3-hydroxydodecanoic acid.

[0013] In a specific embodiment of the present invention, the polyhydroxyalkanoates include but are not limited to one or a combination of two or more of P(HA-LA), P3HP, PHB, P4HB, PHV, PHO, PHN, PHD, PHBV, P34HB, PHBHHp, PHBHHx, P3HB4HB3HV or P3HB4HB5HV.

[0014] The HA in P(HA-LA) includes, but is not limited to, one or a combination of two or more of 3-hydroxypropionic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxypentanoic acid, 5-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, or 3-hydroxydodecanoic acid; and LA is 2-hydroxypropionic acid. Preferably, the molar amount of HA monomer in P(HA-LA) is any value between 10% and 90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 90%. Preferably, the molar amount of LA monomer in P(HA-LA) is any value between 10-90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0015] The molar amount of the 3HV monomer in PHBV is any value between 10% and 90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%.

[0016] The molar amount of 4HB monomer in P34HB is any value between 10-90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0017] The molar amount of the HHp monomer in PHBHHp is any value between 10% and 90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0018] The molar amount of 3HHx monomer in PHBHHx is any value between 10% and 90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0019] The molar amount of the 4HB monomer in P3HB4HB3HV is any value between 10% and 90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0020] The molar amount of the 3HV monomer in P3HB4HB3HV is any value between 10% and 90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0021] The molar amount of the 5HV monomer in P3HB4HB5HV is any value between 10% and 90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0022] The molar amount of 4HB monomer in P3HB4HB5HV is any value between 10-90%, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 90%, etc.

[0023] The raw material comprises two or more polyhydroxyalkanoates, wherein the first polyhydroxyalkanoate is poly-3-hydroxybutyrate (PHB), the second polyhydroxyalkanoate comprises a 4-hydroxybutyric acid (4HB) monomer, and the molar amount of the 4HB monomer in the second polyhydroxyalkanoate is at least 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 90%, 95% or 99% or more; and / or the molar amount of the 4HB monomer in the second polyhydroxyalkanoate is 100%, 99%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25% or 20% or less. In a specific embodiment of the present invention, the molar amount of 4HB monomer in the second polyhydroxyalkanoate is any value between 20% and 90%, any value between 20% and 80%, or any value between 20% and 60%, or any value between 30% and 60%.

[0024] Preferably, the monomer of the second polyhydroxyalkanoate further comprises one or a combination of two or more of 2-hydroxypropionic acid, 3-hydroxypropionic acid, 3-hydroxybutyric acid, 3-hydroxypentanoic acid, 5-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, 3-hydroxyundecanoic acid or 3-hydroxydodecanoic acid. An example of the second polyhydroxyalkanoate may be one or a combination of two or more of P(HA-LA), P4HB, P34HB, P3HB4HB3HV or P3HB4HB5HV, wherein HA comprises at least 4HB monomer.

[0025] Preferably, the weight average molecular weight of the PHB can be any value below 150,000 or above 150,000, for example, any value between 150,000 and 5,000,000, or any value between 300,000 and 1,000,000. Specific examples include 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, 650,000, 700,000, 750,000, 800,000, 850,000, 900,000, 950,000, 1,000,000, 1,500,000, 2,000,000, 2,500,000, 3,000,000, 3,500,000, 4,000,000, 4,500,000 or 5,000,000.

[0026] Preferably, the weight-average molecular weight of the second polyhydroxyalkanoate can be any value below 150,000 or above 150,000, for example, any value between 150,000 and 5,000,000, or any value between 300,000 and 1,000,000. Specific examples include 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, 650,000, 700,000, 750,000, 800,000, 850,000, 900,000, 950,000, 1,000,000, 1,500,000, 2,000,000, 2,500,000, 3,000,000, 3,500,000, 4,000,000, 4,500,000 or 5,000,000.

[0027] By adding a high proportion of 4HB, such as P(34HB), the toughness, ductility, thermal stability, and mechanical properties of the PHA product can be improved. In the two or more polyhydroxyalkanoates included in the raw materials, the molar amount of 4HB monomer is any value between 10% and 90%, for example, 10%, 15%, 20%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%.

[0028] Preferably, the mass ratio of the first polyhydroxyalkanoate to the second polyhydroxyalkanoate is (2-5):1, preferably (2-3):1, for example (2, 2.5, 3, 3.5, 4, 4.5 or 5):1.

[0029] Preferably, in the raw materials, based on parts by mass, the first polyhydroxyalkanoate in the polyhydroxyalkanoate blend material is 30-60 parts, and the second polyhydroxyalkanoate is 20-40 parts.

[0030] The raw materials may contain only polyhydroxyalkanoates or other components. The polyhydroxyalkanoate blend material in the raw materials may contain any value in the range of 20-100%, preferably any value in the range of 50-98%, and more preferably any value in the range of 75-98%, such as 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 76%, 77%, 78%, 79%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100%, etc., by weight.

[0031] In the raw materials, the first polyhydroxyalkanoate blend material comprises any value in the range of 20-100%, preferably any value in the range of 50-70%, such as 20%, 30%, 40%, 50%, 52.4%, 55%, 60%, 65%, 70%, 71.4%, 75%, 76%, 77%, 78%, 79%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100%, etc., according to the mass ratio.

[0032] In the raw materials, the second polyhydroxyalkanoate blend material comprises any value in the range of 10-100%, preferably any value in the range of 10-35%, such as 10%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 35%, 40%, 50%, 52.4%, 55%, 60%, 65%, 70%, 71.4%, 75%, 76%, 77%, 78%, 79%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100%, etc.

[0033] Preferably, the polyhydroxyalkanoate can be prepared by chemical synthesis, biological fermentation or purchased.

[0034] In a specific embodiment of the present invention, the raw materials may further include a filler. The filler may be any organic filler or inorganic filler known in the art, or a combination thereof. Preferably, the filler includes an inorganic filler.

[0035] Preferably, the raw materials comprise, by weight, 70-100 (e.g., 70, 75, 80, 85, 90, 95 or 100, etc.) parts of a polyhydroxyalkanoate blend material and 0-40 (e.g., 0, 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35 or 40, etc.) parts of a filler.

[0036] Preferably, the inorganic filler includes, but is not limited to, one or a combination of two or more of quartz, silica, alumina, zircon, iron oxide, zinc oxide, titanium oxide, silicon nitride, boron nitride, aluminum nitride, silicon carbide, glass, silicone rubber, silicone resin, carbon fiber, mica, graphite, carbon black, ferrite, graphite, diatomaceous earth, clay, kaolin, clay, talc, montmorillonite, smectite, calcium carbonate, manganese carbonate, magnesium carbonate, barium sulfate, or silver powder. Silica may be in any form, such as one or a combination of two or more of fumed silica, fused silica, crystalline silica, amorphous silica, or ultrafine amorphous silica.

[0037] Preferably, the inorganic filler is a silicate, such as one or a combination of two or more of talc, mica, kaolin, montmorillonite or smectite.

[0038] Preferably, the organic filler includes but is not limited to one or a combination of two or more of wood powder, hydrolyzed gelatin, collagen, hydrolyzed animal protein, cellulose acetate butyrate or starch.

[0039] The filler in the raw materials comprises any value between 0-40% by mass, preferably any value between 10-30%, for example, 0%, 5%, 10%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 30%, 35% or 40%, etc.

[0040] The raw materials may only contain polyhydroxyalkanoate blending materials and fillers, and of course may also contain any possible auxiliary agents in the prior art as needed.

[0041] Preferably, the raw materials include, by weight, 70-100 (e.g., 70, 75, 80, 85, 90, 95 or 100, etc.) parts of polyhydroxyalkanoate blend material and 0-10 (e.g., 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.) parts of additive.

[0042] The additives in the raw materials may comprise any value between 0-10%, preferably any value between 1-5%, such as 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., based on a mass ratio.

[0043] Preferably, the auxiliary agent includes but is not limited to one or a combination of two or more of a chain extender, a nucleating agent, a foaming agent, a flame retardant, a coupling agent, a dispersant, a lubricant, an anti-dripping agent, a heat stabilizer, an anti-hydrolysis agent, an antioxidant, a plasticizer or a dye.

[0044] Specifically, the chain extender includes but is not limited to one or a combination of two or more of chain extender X-U993, chain extender BASF ADR 4400, chain extender BASF ADR 4468, chain extender DX-5, chain extender 6901, chain extender MSA7200 or chain extender HER.

[0045] Specifically, the nucleating agent includes but is not limited to one or a combination of two or more of tungsten disulfide, titanium boride, boron nitride, nano-titanium dioxide, nano-silicon dioxide HB-630, hollow glass microspheres or carbon nanotubes.

[0046] Specifically, the foaming agent includes but is not limited to surfactants, chemical foaming agents, and / or physical foaming agents. Preferably, the surfactant includes but is not limited to anionic surfactants and / or nonionic surfactants. More preferably, the anionic surfactant includes but is not limited to one or a combination of two or more of C-70, C-90, fast penetrant T-70, JFC-EP, alkali-resistant penetrant AEP, or alkali-resistant penetrant OEP-70; more preferably, the nonionic surfactant includes but is not limited to one or a combination of two or more of S-80, AEO-3, AEO-4, AEO-5, AEO-7, JFC-1, JFC-2, or JFC-E. The chemical foaming agent includes but is not limited to inorganic foaming agents and organic foaming agents. Preferably, the inorganic foaming agent includes but is not limited to one or a combination of two or more of carbonates, sodium silicate, silicon carbide, sodium chloride, or carbon black; and the carbonate includes but is not limited to one or a combination of two or more of calcium carbonate, magnesium carbonate, ammonium bicarbonate, sodium carbonate, or sodium bicarbonate.

[0047] Specifically, the flame retardants include, but are not limited to, silicon-based flame retardants, phosphorus-based flame retardants, polyhydroxy flame retardants, or nitrogen-based flame retardants. Preferably, the silicon-based flame retardants include, but are not limited to, one or a combination of two or more of polysilicon boroxane, silicone-based fire retardant 3820, or silicon-based flame retardant FCA-107. Preferably, phosphorus-based flame retardants include, but are not limited to, one or a combination of two or more of ammonium polyphosphate, triphenyl phosphate, toluene diphenyl phosphate, DOPO-modified castor oil, phytic acid, or sodium phytate. Polyhydroxy flame retardants include, but are not limited to, one or a combination of two or more of starch, lignin, cellulose, chitosan, cyclodextrin, tannic acid, or itaconic acid. Nitrogen-based flame retardants include, but are not limited to, urea and / or urea-complexed melamine. Preferably, the urea-complexed melamine is a mixture of urea and melamine in a molar ratio of (1-3):2 (preferably physically blended).

[0048] Specifically, the coupling agent includes but is not limited to one or a combination of two or more of silane coupling agent KH550, silane coupling agent KH560, silane coupling agent KH570, silane coupling agent CG-619, silane coupling agent CG-580, silane coupling agent CG-590, silane coupling agent A-172, silane coupling agent KH-792, silane coupling agent DL-602, silane coupling agent Y-5475, silane coupling agent Y-5669, titanate coupling agent AT1618, titanate coupling agent TMC-201, titanate coupling agent TC-TTS, titanate coupling agent TC-130, titanate coupling agent TC-131, maleic anhydride (maleic anhydride (MAH)), titanate coupling agent TMC-102, titanate coupling agent TMC-311 or coupling agent BYKC8003.

[0049] Specifically, the dispersant includes but is not limited to one or a combination of two or more of erucamide, ethylene bisstearamide, stearic acid monoglyceride or tristearin.

[0050] Specifically, the lubricant includes, but is not limited to, ethylene bisstearamide (lubricant EBS), fully biodegradable polyester, or PHA as a lubricant, or a combination of two or more thereof, preferably a low-molecular-weight fully biodegradable polyester or PHA. Preferably, the molecular weight of the fully biodegradable polyester is 1000-8000, and the molecular weight of the PHA as a lubricant is 1500-8000.

[0051] Specifically, the anti-dripping agent includes but is not limited to PTFE powder TRG-460 and / or PTFE powder FS-200.

[0052] Specifically, the heat stabilizer includes but is not limited to one or a combination of two or more of calcium stearate, zinc stearate, magnesium stearate, barium stearate, methyl thioglycolate, heat stabilizer DP1100, nanocellulose, nanomontmorillonite or fumed silica.

[0053] Specifically, the anti-hydrolysis agent includes but is not limited to one or a combination of two or more of anti-hydrolysis agent 936, anti-hydrolysis agent HD900A, anti-hydrolysis agent BTWR-500, Shanghai Langyi HY2000, polycarbodiimide UN-03 or anti-hydrolysis agent TNPP.

[0054] Specifically, the antioxidant includes but is not limited to pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1010), tris(2,4-di-tert-butylphenyl) phosphite or CYANOX 1790, or a combination of two or more thereof.

[0055] Specifically, the plasticizer includes but is not limited to one or a combination of two or more of isosorbide, castor oil derived ester plasticizer, isosorbide diester plasticizer or citrate plasticizer.

[0056] Specifically, the dye includes but is not limited to one or a combination of two or more of phthalocyanine blue, lemon yellow, sun-fast red, iron oxide red, titanium dioxide, light-fast yellow or iron oxide yellow.

[0057] In a specific embodiment of the present invention, the auxiliary agents include but are not limited to coupling agents, nucleating agents, thermal stabilizers, plasticizers, dispersants, lubricants and antioxidants.

[0058] In a specific embodiment of the present invention, the auxiliary agents include but are not limited to coupling agents, nucleating agents, thermal stabilizers, plasticizers and antioxidants.

[0059] In a specific embodiment of the present invention, the auxiliary agent includes but is not limited to a coupling agent, a nucleating agent, a thermal stabilizer and a plasticizer.

[0060] In a specific embodiment of the present invention, the auxiliary agent includes but is not limited to a nucleating agent and a thermal stabilizer.

[0061] Specifically, by adding a nucleating agent (NA), the nucleation density of PHA is increased, and its crystallization rate and crystallinity are improved; by adding a thermal stabilizer and a plasticizer, the thermal stability and melt strength of PHA are improved, and the thermal processing window of PHA is broadened.

[0062] In a specific embodiment of the present invention, the raw materials include, by weight:

[0063] Polyhydroxyalkanoate blend material: 70-100 parts (e.g., 70, 75, 80, 85, 90, 95 or 100 parts, etc.);

[0064] Inorganic filler: 10-30 parts (e.g., 10, 15, 20, 25 or 30 parts, etc.);

[0065] Auxiliary agent: 0-10 parts (for example, 0, 0.5, 0.6, 1, 1.4, 1.5, 1.6, 2, 2.4, 2.5, 2.6, 3, 4, 5, 6, 7, 8, 9 or 10 parts, etc.).

[0066] In a specific embodiment of the present invention, the raw materials include, by weight:

[0067] Polyhydroxyalkanoate blend material: 70-100 parts (e.g., 70, 75, 80, 85, 90, 95 or 100 parts, etc.);

[0068] Inorganic filler: 10-30 parts (e.g., 10, 15, 20, 25 or 30 parts, etc.);

[0069] Plasticizer: 0-1 part (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.);

[0070] Antioxidant: 0-1 part (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.);

[0071] Lubricant: 0-1 part (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.);

[0072] Thermal stabilizer: 0-1 part (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.);

[0073] Coupling agent: 0-1 part (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.);

[0074] Nucleating agent: 0-10 parts (e.g., 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 parts, etc.);

[0075] Dispersant: 0-1 part (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.).

[0076] Furthermore, by improving the process and processing equipment, the sensitivity of PHA to shear rate can be reduced and the thermal workability of PHA can be improved. By using a mold temperature controller, the problem of PHA products sticking to the mold and not easily falling off can be solved, and production efficiency can be improved and production costs can be reduced.

[0077] The melting temperature may be 10° C. to 5° C. below the melting point of the raw material (preferably the polyhydroxyalkanoate blending material in the raw material).

[0078] Preferably, the melting temperature is below 180°C, preferably any value between 130-160°C, such as 130, 140, 150, 160, 170 or 180°C.

[0079] After the melting, a cooling step is further included. Preferably, the cooling can be air cooling or water cooling. Preferably, the cooling temperature can be any value in the range of 5-40°C, such as 5, 10, 15, 20, 25, 30, 35 or 40°C.

[0080] Preferably, pelletizing is performed simultaneously with cooling or pelletizing is performed after cooling to obtain pellets.

[0081] Preferably, the melting comprises adding the raw materials into a barrel equipped with a screw, and achieving melting by the shear force of the rotating screw at a temperature below 180°C.

[0082] The screw is fixed inside the barrel.

[0083] The interior of the barrel can be any irregular shape such as a hollow cylinder, a hollow cuboid, a hollow cube, a hollow ellipsoid, or a hollow cone.

[0084] If the interior is a hollow cylinder, the two ends of the screw are respectively facing the upper and lower bottom surfaces of the cylinder.

[0085] The screw is provided with a screw groove. After the raw material is fed into the barrel from one end of the screw, the raw material is pushed forward in the screw groove to the other end by the rotating screw.

[0086] Further preferably, the aspect ratio of the screw is (36-64):1; for example, (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 or 64, etc.):1.

[0087] More preferably, the screw speed is 150-300 rpm; for example, 150, 170, 180, 200, 220, 230, 250, 280 or 300 rpm.

[0088] The temperature of heating the pellets is any value in the range of 120-170°C, preferably any value in the range of 120-150°C, such as 120, 125, 130, 135, 140, 145, 150, 155, 160, 165 or 170°C.

[0089] The barrel equipped with a screw is a twin-screw extruder. The present application uses differential scanning calorimetry (DSC) isothermal crystallization kinetics analysis to determine that the isothermal temperature between 40-80°C can achieve rapid crystallization of the material. Therefore, the temperature of the isothermal annealing is any value between 40-80°C, preferably any value between 50-80°C, any value between 50-70°C or any value between 60-70°C, such as 40, 45, 50, 55, 60, 65, 70, 75 or 80°C.

[0090] The heating and / or isothermal annealing can be performed in a mold.

[0091] The shape of the mold can be adjusted according to the shape of the product of interest or demand.

[0092] The molded body may be an injection molded body.

[0093] The injection molding pressure is any value between 80 and 140 bar, for example, 80, 90, 100, 110, 120, 130 or 140 bar.

[0094] The injection molding time is greater than 5s, 6s, 7s, 8s, 9s, 10s, 15s, 20s, 25s or 30s.

[0095] In a specific embodiment of the present invention, the molded body is an injection molded body, and the preparation method comprises:

[0096] A) melt-blending and extruding the raw materials at 130-160° C., cooling and granulating at 5-40° C. to obtain injection molding pellets; preferably, the cooling includes but is not limited to air cooling or water cooling;

[0097] B) The injection molding pellets obtained in step A) are passed through a hot runner at 120-170° C., with an injection pressure of 80-140 bar, and injected into a mold at a temperature of 40-80° C. After injection molding, the mold is demolded to obtain an injection molded body.

[0098] Furthermore, the preparation method comprises:

[0099] Step 1: Weigh the corresponding mass parts of polyhydroxyalkanoate blending material, filler and additives, add them into a high-speed mixer and stir for 3 to 10 minutes;

[0100] Step 2: Put the mixed material into a twin-screw extruder for melt blending and extrusion, and then granulate it by air cooling to obtain injection molding pellets.

[0101] Preferably, the twin-screw processing temperature is 130-160°C, the screw speed is 150-300 rpm, and the air cooling temperature is 5-40°C.

[0102] Step 3: Add the prepared injection molding pellets to the injection molding extruder with an extruder temperature of 150-170°C, a hot runner temperature of 120-150°C, an injection pressure of 80-140 bar, a mold temperature of 40-80°C, and an injection time of 20-40s for injection molding.

[0103] The injection molding method can also be selected from gas-assisted molding, injection compression molding, injection blow molding (including one-step and two-step methods), etc. In addition, in-mold molding, gas pressure molding, two-color molding, sandwich molding, push-pull or SCORIM can also be used.

[0104] The present invention also provides a molded body obtained by the above preparation method. Preferably, the molded body is an injection molded body.

[0105] Preferably, the molded body includes but is not limited to at least one of fabric, lunch box, cup, spoon, knife, fork, straw, packaging or medical device.

[0106] "Flash," as used herein, refers to the gaps formed when molten material enters the mold directly or after heating, between the joints of the mold cavity (such as the mold clamping area, insert area, or sliding core sliding area). For example, this occurs when molten material is squeezed from the mold parting surface, creating a thin flake at the edge of the product.

[0107] The "melting point" detection method described in the present invention can be any method in the prior art, preferably differential scanning calorimetry.

[0108] The beneficial effects of this application are as follows:

[0109] A) The PHA processing temperature window is broadened to below 180°C, which reduces the thermal decomposition of PHA and improves the thermal stability of the product (e.g., a reduction in the cold crystallization enthalpy);

[0110] B) Improved PHA melt strength, enhanced moldability of injection molded products, and resolved flash issues;

[0111] C) Improves the toughness of PHA (e.g., improves the notched Izod impact strength) to prevent embrittlement caused by low temperatures;

[0112] D) The crystallization rate of PHA is improved (injection molding within 20-40 seconds), solving the problem of injection molded products sticking to the mold and not easily falling off;

[0113] E) Achieve perfect PHA crystallization, reducing the embrittlement and physical aging of the product caused by post-crystallization;

[0114] F) Improve the weather resistance and heat and humidity resistance of the product as well as the shelf life and shelf life of the product;

[0115] G) Shortened PHA injection molding time and improved production efficiency;

[0116] H) Through the isothermal annealing process, the spherulite size of the material is adjusted to be moderate and uniform, thereby improving the processing performance of the material and obtaining an injection molded product with high strength, high toughness and heat resistance.

[0117] The English abbreviations and Chinese full names of the present invention are compared in Table 1.

[0118] Table 1 BRIEF DESCRIPTION OF THE DRAWINGS

[0119] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which:

[0120] Figure 1: Product image prepared using the raw material components and process conditions of the examples of this application.

[0121] Figure 2: Degrees of flash, where from left to right they are heavy, light, and no flash. DETAILED DESCRIPTION

[0122] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0123] The detection standards of the parameters in the embodiment are as follows:

[0124] 1. Melt index 190℃, 2.16kg (g / 10min), refer to GB / T 3682-2000.

[0125] 2. Tensile strength (MPa), refer to GB / T 1040.2-2006.

[0126] 3. Tensile elongation at break (%), refer to GB / T 1040.2-2006.

[0127] 4. Izod beam notched impact strength (KJ / m 2 ), refer to GB / T 1843-2008.

[0128] 5. Load heat deformation temperature 0.45MPa(℃), refer to GB / T 1634-2019.

[0129] 6. Crystallization temperature (°C), GB / T 19466.3-2004.

[0130] 7. Cold crystallization enthalpy (J / g), GB / T 19466.3-2004.

[0131] 8. Half-crystallization time (t), GB / T 19466.3-2004.

[0132] 9. Glass transition temperature (°C), GB / T 19466.2-2004.

[0133] 10. Flashing: The excess protrusion on the edge of the product is manually observed and the degree of protrusion is classified as none, mild, light, or severe. The specific classification criteria are: no excess protrusion is invisible to the naked eye, indicating no flashing (see the spoon image on the right side of Figure 2); less than 1 / 20 of the edge protrudes, and the protrusion is only just visible to the naked eye, indicating mild flashing; less than 1 / 20 of the edge protrudes, and the flash is clearly visible, or more than 1 / 20 and less than 1 / 2 of the edge protrudes, and the protrusion is only just visible to the naked eye, indicating mild flashing (see the spoon image in the middle of Figure 2); more than 1 / 20 of the edge protrudes, and the flash is clearly visible (see the spoon image on the left side of Figure 2).

[0134] The sources of ingredients used in the examples are as follows:

[0135] Various PHAs were sourced from Beijing Microstructure Biotechnology Co., Ltd.

[0136] Talc: purchased from Langfang Yinma Pigment Co., Ltd., item number: YM-T160.

[0137] The manufacturers and product numbers of the instruments used in the examples are as follows:

[0138] Twin-screw extruder: Nanjing Juli Chemical Machinery Co., Ltd., China, SHJ-35B.

[0139] Injection molding extruder: Ningbo Yinzhou Langyi Plastic Machinery Co., Ltd., LYH3280-X1.

[0140] Mold temperature controller: Dongguan Haibaisi Machinery Technology Co., Ltd., SF504100A.

[0141] Example 1: Effect of mold temperature (isothermal annealing temperature) on molded body properties

[0142] Step 1: Add 52.4 parts by mass of PHB, 25 parts of P34HB (4HB content 20%), 20 parts of talc, 0.2 parts of isosorbide, 0.2 parts of antioxidant 1010, 0.3 parts of lubricant EBS, 0.2 parts of erucamide, 0.2 parts of calcium stearate, 0.5 parts of maleic anhydride (MAH), and 1 part of boron nitride (BN) into a high-speed mixer and stir for 3-10 minutes;

[0143] Step 2: Place the mixed material into a twin-screw extruder for melt blending and extrusion, and then granulate it through air cooling to obtain PHA injection molding special material.

[0144] The twin-screw processing temperature was 155°C, the screw speed was 180 rpm, and the air cooling temperature was 30°C.

[0145] Step 3: Add the prepared injection molding material to an injection molding extruder at an extruder temperature of 165°C, a hot runner temperature of 130°C, and an injection pressure of 120 bar. Inject the molten PHA injection molding material into the mold. The mold temperature is maintained at 40°C, 50°C, 60°C, 70°C, and 80°C. The injection molding process is performed for 20-40 seconds and the mold is demolded. The mold temperature is also maintained during demolding. The performance parameters of the molded body obtained at a mold temperature of 40°C are shown in Table 2. The mechanical properties, impact strength, and heat resistance of the molded bodies obtained at various temperatures are compared in Table 3. Specific products are shown in Figure 1.

[0146] Table 2

[0147] Table 3

[0148] Example 2: Effect of different molar contents of 4HB monomer on performance

[0149] Step 1, add 52.4 parts by mass of PHB, 25 parts of P34HB (4HB content is 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%), 20 parts of talc, 0.2 parts of isosorbide, 0.2 parts of antioxidant 1010, 0.3 parts of lubricant EBS, 0.2 parts of erucamide, 0.2 parts of calcium stearate, 0.5 parts of maleic anhydride (MAH), and 1 part of boron nitride (BN) into a high-speed mixer and stir for 3-10 minutes;

[0150] Step 2: Same as Example 1.

[0151] Step 3: The mold temperature was maintained at 40° C., and the rest was the same as in Example 1. The performance parameters of the obtained molded body are shown in Table 4.

[0152] Table 4

[0153] Control Example 1: Contains no 4HB monomer and boron nitride (BN), and contains very little inorganic filler

[0154] Step 1: Add 97.4 parts by mass of PHB, 0.2 parts of isosorbide, 0.2 parts of antioxidant 1010, 0.3 parts of lubricant EBS, 0.2 parts of erucamide, 0.2 parts of calcium stearate, 1 part of talc, and 0.5 parts of maleic anhydride (MAH) into a high-speed mixer and stir for 3-10 minutes;

[0155] Step 2: Same as Example 1.

[0156] Step 3: Same as Example 1, but the mold temperature is maintained at 40°C.

[0157] The performance parameters of the obtained molded body are shown in Table 5.

[0158] Comparative Example 2: No 4HB monomer, very little inorganic filler, and the additives are the same as in Example 1

[0159] Step 1: Add 96.4 parts by mass of PHB, 0.2 parts of isosorbide, 0.2 parts of antioxidant 1010, 0.3 parts of lubricant EBS, 0.2 parts of erucamide, 0.2 parts of calcium stearate, 1 part of talc, 0.5 parts of maleic anhydride (MAH), and 1 part of boron nitride (BN) into a high-speed mixer and stir for 3-10 minutes;

[0160] Step 2: Same as Example 1.

[0161] Step 3: Same as Example 1, but the mold temperature is maintained at 40°C.

[0162] The performance parameters of the obtained molded body are shown in Table 5.

[0163] Table 5

[0164] Comparative Example 3: The inorganic filler is very small and the additives are the same as those in Example 1

[0165] Step 1: Add 71.4 parts by mass of PHB, 25 parts of P34HB (4HB content 15%), 0.2 parts of isosorbide, 0.2 parts of antioxidant 1010, 0.3 parts of lubricant EBS, 0.2 parts of erucamide, 0.2 parts of calcium stearate, 1 part of talc, 0.5 parts of maleic anhydride (MAH), and 1 part of boron nitride (BN) into a high-speed mixer and stir for 3-10 minutes;

[0166] Step 2: Same as Example 1.

[0167] Step 3: Same as Example 1, but the mold temperature is maintained at 40°C.

[0168] The performance parameters of the obtained molded body are shown in Table 6.

[0169] Table 6

[0170] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0171] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for preparing a molded body, characterized in that: The preparation method comprises the steps of melting raw materials and then granulating to obtain pellets, and then heating the pellets and performing isothermal annealing to form the pellets; the raw materials comprise a blend of two or more polyhydroxyalkanoates, wherein the first polyhydroxyalkanoate is PHB, the second polyhydroxyalkanoate comprises a 4HB monomer, the molar amount of the 4HB monomer in the second polyhydroxyalkanoate is more than 15%, and the mass ratio of the first polyhydroxyalkanoate to the second polyhydroxyalkanoate is (2-5):

1.

2. The preparation method according to claim 1, characterized in that: The molar amount of 4HB monomer in the second polyhydroxyalkanoate is 20%-90%.

3. The preparation method according to claim 1, characterized in that: The monomer of the second polyhydroxyalkanoic acid ester also includes one or a combination of two or more of 2-hydroxypropionic acid, 3-hydroxypropionic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, 5-hydroxyvaleric acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, 3-hydroxyundecanoic acid or 3-hydroxydodecanoic acid.

4. The preparation method according to claim 1, characterized in that: The second polyhydroxyalkanoate is one or a combination of two or more of P(HA-LA), P4HB, P34HB, P3HB4HB3HV or P3HB4HB5HV, wherein HA contains at least 4HB monomer.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The raw materials also include fillers; Preferably, the raw materials include, by weight: 70-100 parts of polyhydroxyalkanoate blending material and 0-40 parts of filler.

6. The preparation method according to claim 5, characterized in that: The filler includes an inorganic filler; Preferably, the inorganic filler is selected from one or a combination of two or more of quartz, silica, alumina, zircon, iron oxide, zinc oxide, titanium oxide, silicon nitride, boron nitride, aluminum nitride, silicon carbide, glass, silicone rubber, silicone resin, carbon fiber, mica, graphite, carbon black, ferrite, graphite, diatomaceous earth, kaolin, clay, talc, calcium carbonate, manganese carbonate, magnesium carbonate, barium sulfate or silver powder.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The raw materials also include auxiliary agents; Preferably, the raw materials include, by weight: 70-100 parts of polyhydroxyalkanoate blending material and 0-10 parts of auxiliary agent.

8. The preparation method according to claim 7, characterized in that: The auxiliary agent is selected from one or a combination of two or more of a chain extender, a nucleating agent, a foaming agent, a flame retardant, a coupling agent, a dispersant, a lubricant, an anti-dripping agent, a heat stabilizer, an anti-hydrolysis agent, an antioxidant, a plasticizer or a coloring agent.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The melting temperature is below 180°C, preferably 130-160°C; Preferably, the melting comprises adding the raw materials into a barrel equipped with a screw, and achieving melting by the shear force of the rotating screw at a temperature below 180°C.

10. The preparation method according to claim 9, characterized in that: The aspect ratio of the screw is (36-64):

1.

11. The preparation method according to claim 9, characterized in that: The screw speed is 150-300 rpm.

12. The preparation method according to any one of claims 1 to 11, characterized in that: The pellets are heated to a temperature of 120-170°C, preferably 120-150°C.

13. The preparation method according to any one of claims 1 to 12, characterized in that: The isothermal annealing temperature is 40-80°C.

14. The preparation method according to any one of claims 1 to 13, characterized in that: The molded body is an injection molded body, and the preparation method comprises: A) melt-blending and extruding the raw materials at 130-160° C., cooling and granulating at 5-40° C. to obtain injection molding pellets; preferably, the cooling is selected from air cooling or water cooling; B) The injection molding pellets obtained in step A) are passed through a hot runner at 120-170° C., the injection molding pressure is set at 80-140 bar, and injected into a mold at a temperature of 40-80° C. After injection molding, the mold is demolded to obtain an injection molded body.

15. A shaped body obtained by the preparation method according to any one of claims 1 to 14.

16. The molded body according to claim 15, characterized in that The molded body comprises at least one of fabric, lunch box, cup, spoon, knife, fork, straw, packaging or medical device.

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