Biodegradable material, preparation method and application thereof, and molded body

Abstract

The invention relates to a biodegradable material as well as a preparation method and application thereof and a molded body. The biodegradable material comprises the following components in parts by weight: 30-80 parts of biodegradable resin; 5-75 parts of wet starch; 0.5 to 10 parts of a plasticizer; the moisture content of the wet starch is 20-50%. According to the invention, the wet starch is added into the biodegradable material, and the use amount of the biodegradable resin is reduced by using the good biodegradability of the wet starch, so that the production cost is reduced. The wet starch and the plasticizer are compounded, bound water in the wet starch provides a channel for the plasticizer, and the wet starch and the plasticizer synergistically endow the wet starch with more excellent thermoplasticity, so that the biodegradable material has excellent mechanical properties. The starch product which is not dried in a starch preparation process can be selected as a wet starch source, so that the reverse operation of'drying-rehydration 'is avoided, and the production energy consumption and the transportation and storage cost are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of biodegradable materials, and more particularly to a biodegradable material, its preparation method and application, and a molded form thereof. Background Technology

[0002] Biodegradable materials have garnered widespread attention due to their applications in food packaging, biomedicine, agricultural films, and disposable products. Currently, common biodegradable resins on the market include polylactic acid, diacid and diol copolyesters, and polyhydroxyalkanoates. However, limited by technology and processing, the price of biodegradable resins far exceeds that of petroleum-based plastics. Starch, as a naturally abundant polymer, is often added to biodegradable materials to reduce production costs and increase competitiveness due to its renewable, biodegradable, and low-cost advantages.

[0003] In existing technologies, while adding native starch (untreated starch) can reduce the production cost of biodegradable materials, its strongly polar hydroxyl structure leads to poor compatibility with hydrophobic polylactic acid and other biodegradable resins, easily causing interfacial defects and resulting in decreased mechanical properties and reduced processing flowability of biodegradable materials. Furthermore, the high hydrophilicity of native starch accelerates the uncontrolled degradation of biodegradable materials in humid environments, limiting their application scenarios. To improve the compatibility between starch and biodegradable resins, modified starch, by introducing hydrophobic groups and altering its molecular weight or particle structure, can effectively reduce its own polarity and enhance its interfacial bonding with biodegradable resins. In biodegradable materials, native or modified starch needs to undergo plasticizing treatment or the addition of plasticizers to make it thermoplastic. By disrupting intermolecular hydrogen bonds and enhancing molecular chain mobility, it transforms from a granular crystalline structure into a flowing amorphous melt, thereby improving compatibility and processability with biodegradable resins.

[0004] CN108795001A, CN111763410A, and CN118725758A all disclose technical solutions for adding plasticizers to biodegradable polymer compositions to improve the compatibility between starch and biodegradable resins and achieve a plasticizing effect. However, the relevant mechanical properties of biodegradable materials prepared in the prior art still need to be improved. However, further increasing the amount of plasticizer added is not conducive to the molding performance and mechanical properties of the material, and further increases the production cost.

[0005] Therefore, how to provide a biodegradable material with low preparation cost, excellent mechanical properties, and good molding performance has become an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a biodegradable material, its preparation method, applications, and molded articles. This invention reduces the amount of biodegradable resin used by adding wet starch to the biodegradable material, leveraging its excellent biodegradability, thereby lowering production costs. Furthermore, this invention employs a combination of wet starch and a plasticizer. The bound water in the wet starch provides a channel for the plasticizer, and the two work synergistically to impart superior thermoplasticity to the wet starch, resulting in excellent mechanical properties for the biodegradable material. This invention can use starch products that have not undergone drying treatment in the starch preparation process as the source of wet starch, avoiding the reverse operation of "drying-rehydration," significantly reducing production energy consumption and transportation and storage costs.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a biodegradable material, which comprises the following components by weight: 30-80 parts of biodegradable resin, 5-75 parts of wet starch, and 0.5-10 parts of plasticizer;

[0009] The moisture content of the wet starch is 20-50%.

[0010] The composition includes: 30-80 parts of biodegradable resin (e.g., 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 parts); 5-70 parts of wet starch (e.g., 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or 75 parts); 0.5-10 parts of plasticizer (e.g., 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts); and a moisture content of 20-50% for the wet starch (e.g., 20%, 25%, 30%, 35%, 40%, 45%, or 50%).

[0011] The water in starch can be divided into free water and bound water. Free water exists in the gaps between starch granules, capillaries, or pores on the starch surface, and basically does not form hydrogen bonds with starch molecules. Bound water, on the other hand, penetrates deep into the starch granules and links with the hydroxyl groups on starch molecules through hydrogen bonds. In actual production, when wet starch is dried, both free water and bound water are removed to a certain extent, but the final amount of water is mainly bound water. If additional water is added to the dried starch, most of the water in the starch will exist in the form of free water. Therefore, the wet starch used in this invention is essentially a mixture of starch and water with a higher proportion of bound water. During the starch plasticization process, bound water plays a certain plasticizing role. At the same time, when a plasticizer is added, some of the bound water is replaced by the plasticizer, which links with the hydroxyl groups on starch molecules through hydrogen bonds, widening the spacing between starch molecules and playing a stronger plasticizing role. This improves the compatibility of wet starch with biodegradable resins, giving biodegradable materials excellent mechanical properties. Using wet starch can also lower the starch gelatinization temperature, reducing energy consumption and the risk of thermal degradation during thermomechanical processing.

[0012] The higher the moisture content of the wet starch used in this invention, the more plasticizer can migrate into the starch granules, which is more conducive to the migration of plasticizer and the plasticization of starch. However, since the wet modified starch undergoes centrifugal dehydration or pressure filtration dehydration before drying in the actual production process of modified starch, its actual moisture content is ≤50%. Therefore, this invention limits the moisture content of the wet starch to ≤50%.

[0013] The wet starch described in this invention is wet native starch and / or wet modified starch containing 20-50% bound water.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0015] Preferably, the moisture content of the wet starch is 30-45%, for example, it can be 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44% or 45%, etc.

[0016] The preferred moisture content of the wet starch in this invention is 30-45%. High moisture content in wet starch promotes plasticization and reduces the amount of plasticizer required. However, if the moisture content is too high, the starch granules will stick together, making it difficult for the plasticizer to penetrate the starch granules. Furthermore, due to starch adhesion, the starch is prone to agglomeration during the preparation of biodegradable materials, resulting in uneven dispersion with other components and affecting product performance. High moisture content in the product significantly impacts subsequent processing and use. Conversely, if the proportion of bound water in the wet starch is low, its plasticizing properties deteriorate.

[0017] Preferably, the biodegradable resin comprises any one or a combination of at least two of polylactic acid (PLA), polybutylene succinate (PBS), polybutylene adipate (PBSA), polybutylene terephthalate (PBST), polybutylene adipate (PBAT), polycaprolactone (PCL), polyglycolic acid (PGA), or polyhydroxyalkanoate (PHA).

[0018] The biodegradable resins include materials that are completely degraded into low-molecular-weight compounds by the action of naturally occurring microorganisms such as bacteria, molds (fungi) and algae, or materials that can meet or pass standards such as ISO-14855, EN-13432, and ASTM-D6400 and are completely biodegradable.

[0019] Preferably, the wet starch comprises wet native starch and / or wet modified starch.

[0020] Preferably, the wet starch comprises any one or a combination of at least two of potato starch, corn starch, cassava starch, sweet potato starch, pea starch, rice starch, or mung bean starch.

[0021] Preferably, the wet-modified starch includes any one or a combination of at least two of the following: pregelatinized starch, oxidized starch, acetylated distarch phosphate, hydroxypropyl starch, acid-hydrolyzed starch, enzymatically converted dextrin, enzymatically hydrolyzed starch, octenyl succinate starch ester, yellow dextrin, white dextrin, alkali-treated starch, bleached starch, monosaccharide phosphate, distarch glycerol ester, phosphated distarch, acetylated distarch adipate, phosphorylated distarch phosphate ester, acetate starch, acetylated distarch, hydroxypropyl distarch phosphate ester, hydroxypropyl distarch glycerol ester, acetylated oxidized starch, octenyl succinate starch aluminum, or oxidized hydroxypropyl starch.

[0022] The wet modified starch is a mixture of modified starch and water that has undergone modification treatment during the preparation of various modified starches using different starch raw materials. Specifically, it can be a starch slurry that has undergone starch pretreatment, various modification reactions, acid-base neutralization, and washing; it can also be a starch slurry that has undergone starch pretreatment, various modification reactions, acid-base neutralization, and washing during the preparation of various modified starches, followed by centrifugation and dehydration of wet modified starch; it can also be a mixture of modified starch and water before conventional drying methods during the preparation of various modified starches; or it can be modified starch with a moisture content ≥20% after modification treatment.

[0023] The wet native starch includes a mixture of water and native starch produced during the production process without drying, or native starch with a moisture content of ≥20%.

[0024] Preferably, the wet starch includes starch products that have not undergone drying treatment during the starch preparation process.

[0025] This invention can use starch products that have not been dried in the starch preparation process as the source of wet starch. By combining the starch preparation process with the biodegradable material preparation process, there is no need to perform the drying-pulverizing step after the starch preparation is completed. The obtained starch product can be directly put into the biodegradable material preparation process without the need for additional water addition. This avoids the reverse operation of "drying-rehydration" and greatly reduces production energy consumption and transportation and storage costs.

[0026] Preferably, the plasticizer comprises any one or a combination of at least two of glycerol, diglycerol, triglycerol, mannitol, 1,2-propanediol, diethanolamine, triethanolamine, sorbitol, xylitol, cetyl alcohol, octadecanol, cyclohexanehexol, or pentaerythritol.

[0027] Preferably, the biodegradable material further includes any one or a combination of at least two of chain extenders, antioxidants, lubricants, or anti-hydrolysis agents.

[0028] Preferably, the biodegradable material includes 0.1-1 parts by weight of chain extender, such as 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts or 1 part, etc.

[0029] Preferably, the biodegradable material includes 0.1-1 parts by weight of antioxidant, such as 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts or 1 part, etc.

[0030] Preferably, the biodegradable material includes 0.1-2 parts of lubricant by weight, for example, 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, or 2 parts, etc.

[0031] Preferably, the biodegradable material includes 0.1-1 parts by weight of an anti-hydrolysis agent, such as 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, or 1 part.

[0032] Preferably, the chain extender comprises an epoxy-type chain extender.

[0033] This invention improves the compatibility between biodegradable resins and wet starch by adding chain extenders to biodegradable materials. Since different biodegradable resins have different solubility parameters, directly blending two or more biodegradable resins will cause phase separation in the prepared biodegradable materials, molded bodies or products, resulting in poor mechanical properties and obvious stratification. The addition of chain extenders can improve the compatibility between biodegradable resins and wet starch and improve the mechanical properties of biodegradable materials.

[0034] Preferably, the antioxidant includes any one or a combination of at least two of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0035] This invention adds antioxidants to biodegradable materials, which can eliminate free radicals generated during the preparation, storage, and use of the materials, promote the decomposition of hydroperoxides, prevent chain reactions, and delay or inhibit the oxidation process of the materials.

[0036] Preferably, the lubricant comprises fatty acid salts and / or fatty amides, preferably any one or a combination of at least two of calcium stearate, magnesium stearate, sodium stearate, oleamide or erucamide.

[0037] This invention reduces frictional heat between components of biodegradable materials by adding lubricants, thus preventing thermal degradation. Furthermore, the addition of lubricants improves the processing performance of biodegradable materials. This invention preferably uses fatty acid salts and fatty amides as lubricants, which can prevent material adhesion in subsequent applications, improve the material's openness (e.g., when biodegradable materials are made into thin films, the high surface energy between films makes separation difficult), and also enhance the antistatic properties of biodegradable materials.

[0038] Preferably, the anti-hydrolysis agent comprises any one or a combination of at least two of N,N'-bis(2,6-diisopropylphenyl)carbodiimide, poly(1,3,5-triisopropylphenyl)carbodiimide, or polymeric carbodiimide.

[0039] This invention effectively inhibits the performance degradation of biodegradable materials caused by hydrolysis by adding an anti-hydrolysis agent, including problems such as decreased viscosity, reduced mechanical properties, yellowing, and cracking. This allows the biodegradable materials to maintain stable performance under harsh conditions such as high temperature and humidity, and acid and alkaline environments, thus extending the service life of the biodegradable materials.

[0040] In a second aspect, the present invention provides a method for preparing a biodegradable material as described in the first aspect, the method comprising the following steps:

[0041] The above-mentioned biodegradable resin, wet starch, plasticizer, optionally chain extender, optionally antioxidant, optionally lubricant and optionally anti-hydrolysis agent are mixed in parts by weight and then subjected to molding to obtain the biodegradable material.

[0042] Preferably, the mixing includes premixing, dynamic mixing, or melt blending.

[0043] Preferably, the premixing operation involves mixing the biodegradable resin, wet starch, plasticizer, optionally chain extender, optionally antioxidant, optionally lubricant, and optionally anti-hydrolysis agent in a mixer according to the weight ratio, and then feeding them into the molding equipment for molding operation.

[0044] Preferably, the mixer includes a high-speed mixer, a twin-ribbon mixer, or a drum mixer.

[0045] The present invention does not limit the mixing speed of the mixer, as long as the components are fully mixed.

[0046] Preferably, the mixing time is 3-5 minutes, for example, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes.

[0047] Preferably, the melt blending includes open mill blending, internal mixer blending, single screw extruder blending, or twin screw extruder blending.

[0048] Preferably, the melt blending temperature is 120-210℃, for example, it can be 120℃, 140℃, 180℃, 200℃ or 210℃.

[0049] Preferably, the dynamic mixing includes mixing via a hopper metering pump, mixing via a loss-in-weight scale, or mixing via multiple feed inlets in a twin-screw extruder.

[0050] Preferably, the molding operation includes extrusion molding, injection molding, calendering, casting, blow molding, or biaxial stretching molding.

[0051] Preferably, the extrusion molding is performed in a twin-screw extruder.

[0052] This invention does not limit the model of the twin-screw extruder or the diameter of the extruder screw. A parallel co-rotating twin-screw extruder with a length-to-diameter ratio of (32-56):1 (for example, it can be 32:1, 35:1, 40:1, 45:1, 50:1, 55:1 or 56:1) can be used for extrusion molding.

[0053] The twin-screw extruder is equipped with one or more natural vents and / or one or more vacuum vents.

[0054] During the extrusion molding process of the biodegradable material provided by this invention in a twin-screw extruder, under a certain heating temperature and the shearing of the twin screws, the moisture in the wet starch evaporates through the natural exhaust port and the vacuum exhaust port. The twin-screw extruder has no limit on the moisture content of the wet starch.

[0055] Preferably, the extrusion molding temperature is 40-240℃, for example, it can be 40℃, 80℃, 120℃, 160℃, 200℃ or 240℃.

[0056] Preferably, the extrusion speed is 100-500 r / min, for example, it can be 100 r / min, 200 r / min, 300 r / min, 400 r / min or 500 r / min.

[0057] Preferably, the extrusion molding process further includes a cooling and pelletizing step.

[0058] Cooling pelletizing refers to the process of cooling and pelletizing biodegradable materials after twin-screw extrusion. The cooling pelletizing methods include, but are not limited to: conveyor belt fan cooling and pelletizing by pelletizer (air cooling), cooling under water bath conditions of different temperatures in water tank and pelletizing by pelletizer (water cooling), die surface hot cutting and air cooling (die surface air cooling), die surface pelletizing and water cooling (die surface water cooling), or underwater pelletizing.

[0059] Preferably, the blow molding is performed in a blown film machine.

[0060] Preferably, the die head temperature of the blown film machine is 130-190℃, for example, it can be 130℃, 140℃, 150℃, 170℃, 180℃ or 190℃.

[0061] Preferably, the biodegradable material after molding includes particulate materials, spherical materials, film materials, sheets, injection molded parts, etc.

[0062] Thirdly, the present invention provides the application of the biodegradable material as described in the first aspect in plastic products.

[0063] Preferably, the plastic products include packaging materials, disposable household items, and covering films.

[0064] Fourthly, the present invention provides a biodegradable particle molded body obtained by extrusion molding of the biodegradable material as described in the first aspect.

[0065] Fifthly, the present invention provides a biodegradable film molded from the biodegradable material as described in the first aspect by blow molding.

[0066] Compared with the prior art, the present invention has at least the following beneficial effects:

[0067] (1) By adding wet starch to biodegradable materials, the present invention can improve the degradation rate of biodegradable materials, reduce the amount of biodegradable resin used, and thus reduce production costs.

[0068] (2) The present invention uses a combination of wet starch and plasticizer. The bound water in the wet starch provides a channel for the plasticizer. The two work together to give the wet starch better thermoplasticity, so that the biodegradable material has excellent mechanical properties.

[0069] (3) The present invention can use starch products that have not been dried in the starch preparation process as wet starch source. Combining starch preparation process and biodegradable material preparation process, there is no need to perform drying-pulverizing steps after starch preparation. The obtained starch product can be directly put into biodegradable material preparation process without the need for additional water addition, avoiding the reverse operation of "drying-rehydration", and greatly reducing production energy consumption and transportation and storage costs.

[0070] (4) Specifically, the biodegradable material provided by the present invention has excellent mechanical properties, with tensile strength of 21.14-34.14 MPa, elongation at break of 311-541%, right-angle tear strength of 117-203 kN / m, pendulum impact resistance of 181-2.91 J, and puncture strength of 1.96-2.71 N. Detailed Implementation

[0071] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0072] The specific information of the materials used in the following specific embodiments of the present invention is as follows:

[0073] Biodegradable resin, PBAT, TH801T, purchased from Xinjiang Lanshan Tunhe Chemical Co., Ltd.

[0074] Biodegradable resin, PLA, REVODE20, purchased from Zhejiang Hisun Biomaterials Co., Ltd.

[0075] Biodegradable resin, PBSA, TH802A, purchased from Xinjiang Lanshan Tunhe Chemical Co., Ltd.

[0076] Biodegradable resin, PBST, TS159, purchased from Sinopec Yizheng Chemical Fiber Co., Ltd.

[0077] Biodegradable resin, PCL, 6500D, purchased from Ingenway Functional Materials (Zhuhai) Co., Ltd.

[0078] Biodegradable resin, PGA, purchased from Shanghai Pujing Chemical Technology Co., Ltd.

[0079] Biodegradable resin, PHA, PB3000G, was purchased from Beijing Microstructure Workshop Biotechnology Co., Ltd.

[0080] Chain extender, ADR-4300-F, purchased from BASF;

[0081] Chain extender, ADR-4370-F, purchased from BASF;

[0082] Chain extender, ADR-4400, purchased from BASF;

[0083] Chain extender, ADR-4468, purchased from BASF;

[0084] The wet starch used in this invention is all from Jiangsu Sanshu Biotechnology Co., Ltd.

[0085] Examples 1-12

[0086] This embodiment provides a biodegradable material and its preparation method. The biodegradable material is a biodegradable particle or a biodegradable film, and its composition is shown in Tables 1-2 (all amounts of each biodegradable material component in Tables 1-2 are parts by weight). "--" indicates that the component was not added. The preparation method is as follows:

[0087] Biodegradable resin, wet starch, plasticizer, and optionally chain extender, optional antioxidant, optional lubricant, or optional anti-hydrolysis agent are mixed to obtain a premix (mixing time is 4 min, and the mixing method and mixing temperature are detailed in Table 1-2). The premix is ​​then extruded through a twin-screw extruder to obtain biodegradable particles (the twin-screw extruder speed is 300 r / min, and the melt temperature of the twin-screw extruder is detailed in Table 1-2).

[0088] A premix is ​​prepared by mixing biodegradable resin, wet starch, plasticizer, and optionally chain extender, optional antioxidant, optional lubricant or optional anti-hydrolysis agent (mixing time is 4 min, mixing method and mixing temperature are detailed in Table 1-2), and then blow molding is performed to obtain a biodegradable film (the maximum temperature of the die head of the blown film machine is detailed in Table 1-2).

[0089] Table 1

[0090]

[0091] Table 2

[0092]

[0093] Example 13

[0094] This embodiment provides a biodegradable material and its preparation method.

[0095] The difference from Example 1 is that in this example, the amount of acid-hydrolyzed starch added is 33.3 parts and the moisture content is 25%.

[0096] Example 14

[0097] This embodiment provides a biodegradable material and its preparation method.

[0098] The difference from Example 1 is that in this example, the amount of acid-hydrolyzed starch added is 50 parts and the moisture content is 50%.

[0099] Comparative Example 1

[0100] This comparative example provides a biodegradable material and its preparation method.

[0101] The difference from Example 1 is that in this comparative example, the amount of acid-hydrolyzed starch added is 28.45 parts and the moisture content is 12.12%. When preparing biodegradable materials, some water is added, and it is calculated that the moisture content of starch can reach 30.15%.

[0102] Comparative Example 2

[0103] This comparative example provides a biodegradable material and its preparation method.

[0104] The difference from Example 1 is that in this comparative example, the amount of plasticizer added is 6 parts.

[0105] Comparative Example 3

[0106] This comparative example provides a biodegradable material and its preparation method.

[0107] The difference from Example 1 is that in this comparative example, the amount of acid-hydrolyzed starch added is 28.45 parts, the moisture content is 12.12%, and the amount of plasticizer added is 6 parts.

[0108] Comparative Example 4

[0109] This comparative example provides a biodegradable material and its preparation method.

[0110] The difference from Example 1 is that in this comparative example, the amount of acid-hydrolyzed starch added is 28.45 parts, and the moisture content is 12.12%.

[0111] Comparative Example 5

[0112] This comparative example provides a biodegradable material and its preparation method.

[0113] The difference from Example 1 is that in this comparative example, the acid-hydrolyzed starch is oven-dried starch, and its addition amount is 25 parts.

[0114] Test methods

[0115] The moisture content of wet starch was tested according to the standard GB / T 6284-2006.

[0116] Performance evaluation methods for biodegradable particle molded bodies:

[0117] Melt mass flow rate (MFR, g / 10 min): conducted according to Method A in GB / T 3682.1-2018, using test conditions of 190℃ and 2.16 kg load;

[0118] Moisture content of biodegradable materials: tested according to the standard GB / T 6284-2006.

[0119] Performance evaluation methods for biodegradable film molded articles:

[0120] Tensile strength (MPa) and elongation at break (%): According to GB / T 1040.3-2006, type 2 specimens were used, with a length of 150 mm and a width of 15 mm. The testing speed was 200 mm / min. Data were measured in both the longitudinal and transverse directions.

[0121] Right-angle tear strength test (kN / m): The test is conducted in accordance with the standard GB / T 16578.2-2009, and the data in both the longitudinal and transverse directions of the sample are measured.

[0122] Pendulum impact resistance (J): Tested according to GB / T 8809-2015 standard;

[0123] Puncture strength (N): Tested according to the standard GB / T 10004-2008.

[0124] Test Results

[0125] The biodegradable particle molded articles and biodegradable film molded articles provided in Examples 1-14 and Comparative Examples 1-5 were tested, and the test results are shown in Table 3 below:

[0126] Table 3

[0127]

[0128] The test results show that:

[0129] (1) As can be seen from Examples 1 to 14, the present invention adds wet starch to biodegradable materials. The bound water in the wet starch provides a channel for the plasticizer. The two work together to give the wet starch better thermoplasticity, so that the biodegradable materials have excellent mechanical properties. The tensile strength can reach 21.14-34.14 MPa, the elongation at break can reach 311-541%, the right angle tear strength can reach 117-203 kN / m, the pendulum impact resistance can reach 181-2.91 J, and the puncture strength can reach 1.96-2.71 N.

[0130] (2) As can be seen from Examples 1 and 13-14, the present invention can achieve better plasticizing effect on biodegradable materials by further optimizing the moisture content of wet starch.

[0131] (3) As can be seen from Example 1 and Comparative Example 1, the high moisture content of wet modified starch is beneficial to starch plasticization. Adding a large proportion of water does not have a further plasticizing effect. Moreover, the biodegradable particle molded body provided by Comparative Example 1 has a high moisture content, and the mechanical properties of the biodegradable film molded body provided are all inferior to those of Example 1.

[0132] (4) As can be seen from Example 1 and Comparative Example 2, the mechanical properties of the biodegradable film molded body are not much different from those of Example 1 when the amount of plasticizer is further increased. Therefore, the high moisture content of wet starch is beneficial to the plasticization of starch and can reduce the amount of plasticizer added.

[0133] (5) As can be seen from Example 1 and Comparative Example 3, the mechanical properties of the biodegradable film molded body prepared by using conventional powder modified starch products with low moisture content and the amount of plasticizer added are slightly worse than those of Example 1.

[0134] (6) As can be seen from Example 1 and Comparative Examples 4-5, only by adding wet starch with low moisture content or not adding water to the biodegradable material system containing starch, the mechanical properties of the biodegradable material are significantly degraded.

[0135] 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 biodegradable material, characterized in that, The biodegradable material comprises the following components by weight: 30-80 parts of biodegradable resin, 5-75 parts of wet starch, and 0.5-10 parts of plasticizer; The moisture content of the wet starch is 20-50%.

2. The biodegradable material according to claim 1, characterized in that, The moisture content of the wet starch is 30-45%.

3. The biodegradable material according to claim 1 or 2, characterized in that, The biodegradable resin includes any one or a combination of at least two of the following: polylactic acid, polybutylene succinate, polybutylene adipate, polybutylene succinate terephthalate, polybutylene adipate terephthalate, polycaprolactone, polyglycolic acid, or polyhydroxyalkanoate.

4. The biodegradable material according to any one of claims 1-3, characterized in that, The wet starch includes wet native starch and / or wet modified starch; Preferably, the wet starch comprises any one or a combination of at least two of potato starch, corn starch, cassava starch, sweet potato starch, pea starch, rice starch, or mung bean starch; Preferably, the wet-modified starch includes any one or a combination of at least two of the following: pregelatinized starch, oxidized starch, acetylated distarch phosphate, hydroxypropyl starch, acid-hydrolyzed starch, enzyme-converted dextrin, enzyme-hydrolyzed starch, octenyl succinate starch ester, yellow dextrin, white dextrin, alkali-treated starch, bleached starch, monosaccharide phosphate, distarch glycerol ester, phosphated distarch, acetylated distarch adipate, phosphorylated distarch phosphate, acetate starch, acetylated distarch, hydroxypropyl distarch phosphate, hydroxypropyl distarch glycerol ester, acetylated oxidized starch, octenyl succinate starch aluminum, or oxidized hydroxypropyl starch. Preferably, the plasticizer comprises any one or a combination of at least two of glycerol, diglycerol, triglycerol, mannitol, 1,2-propanediol, diethanolamine, triethanolamine, sorbitol, xylitol, cetyl alcohol, octadecanol, cyclohexanehexol, or pentaerythritol.

5. The biodegradable material according to any one of claims 1-4, characterized in that, The biodegradable material further includes any one or a combination of at least two of chain extenders, antioxidants, lubricants, or anti-hydrolysis agents; Preferably, the biodegradable material comprises 0.1-1 parts by weight of a chain extender; Preferably, the biodegradable material comprises 0.1-1 parts by weight of antioxidant; Preferably, the biodegradable material comprises 0.1-2 parts by weight of lubricant; Preferably, the biodegradable material includes 0.1-1 parts by weight of an anti-hydrolysis agent; Preferably, the chain extender comprises an epoxy chain extender; Preferably, the antioxidant includes any one or a combination of at least two of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants; Preferably, the lubricant comprises fatty acid salts and / or fatty amides; Preferably, the anti-hydrolysis agent comprises any one or a combination of at least two of N,N'-bis(2,6-diisopropylphenyl)carbodiimide, poly(1,3,5-triisopropylphenyl)carbodiimide, or polymeric carbodiimide.

6. A method for preparing a biodegradable material as described in any one of claims 1-5, characterized in that, The preparation method of the biodegradable material includes the following steps: The above-mentioned biodegradable resin, wet starch, plasticizer, optionally chain extender, optionally antioxidant, optionally lubricant and optionally anti-hydrolysis agent are mixed in parts by weight and then subjected to molding to obtain the biodegradable material.

7. The method for preparing the biodegradable material according to claim 6, characterized in that, The mixing includes premixing, dynamic mixing, or melt blending; Preferably, the mixing time is 3-5 minutes; Preferably, the molding operation includes extrusion molding, injection molding, calendering, casting, blow molding, or biaxial stretching molding; Preferably, the extrusion molding is performed in a twin-screw extruder; The extrusion molding temperature is 40-240℃; Preferably, the extrusion molding speed is 100-500 r / min; Preferably, the blow molding is performed in a blown film machine; Preferably, the die head temperature of the blown film machine is 130-190℃.

8. The application of a biodegradable material as described in any one of claims 1-5 in plastic articles.

9. A biodegradable particle molded body obtained by extrusion molding of the biodegradable material as described in any one of claims 1-5.

10. A biodegradable film molded from the biodegradable material as described in any one of claims 1-5 by blow molding.

Images