Biodegradable composition and application thereof
By compounding thermoplastic starch with polylactic acid at a specific thermal weight loss percentage, the problem of weak puncture resistance of biodegradable materials was solved, resulting in a puncture-resistant film bag material with high bio-based content and low cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KINGFA SCI & TECH CO LTD
- Filing Date
- 2026-03-04
- Publication Date
- 2026-05-19
AI Technical Summary
Existing biodegradable materials have weak puncture resistance, especially as they become thinner and cannot withstand sharp objects. Furthermore, reducing starch content will affect the bio-based content and increase costs, and multilayer membrane structure equipment has high requirements.
By combining thermoplastic starch with biodegradable polyester and polylactic acid at a specific thermal weight loss percentage, and controlling the slippage and movement of starch molecular chains, a membrane bag material with good puncture resistance is prepared.
It improves the puncture displacement and puncture resistance of biodegradable materials, meets the requirements for lightweighting and thinning, maintains high bio-based content, and reduces costs.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials technology, specifically relating to a biodegradable composition and its application. Background Technology
[0002] Compared to traditional polyethylene (PE), biodegradable materials, such as blends formed from flexible biodegradable polyester, polylactic acid, and starch, have biodegradable properties and a certain bio-based content that can help reduce carbon emissions. They can be widely used in supermarket shopping bags, logistics and express delivery bags, garbage bags, industrial product packaging bags, and other fields.
[0003] However, the puncture resistance of films made from such materials is relatively weak, especially their ability to resist deformation during puncture, resulting in small puncture displacement. Furthermore, with the development of the industry, lightweighting and thinning are the major trends in the future production of biodegradable films. Under the trend of thinning, the puncture resistance of biodegradable films is faced with greater challenges, which limits their application in carrying certain sharp objects.
[0004] Currently, there are two main methods to improve the puncture resistance of biodegradable materials: one is to reduce the starch content in the biodegradable material or even use a starch-free filling solution; the other is to use a multilayer membrane structure. However, reducing the starch content directly reduces the bio-based content of the blend system, weakening its carbon reduction characteristics, and also increases costs. Multilayer membrane structures place excessive demands on equipment, resulting in high equipment costs and reduced efficiency.
[0005] Therefore, developing a starch-containing biodegradable composition with good puncture resistance is an urgent problem to be solved in this field. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the present invention aims to provide a biodegradable composition and its applications. Materials prepared from the biodegradable composition exhibit large puncture displacement, strong resistance to deformation during puncture, and good puncture resistance.
[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a biodegradable composition comprising, by weight, 50-89 parts of biodegradable polyester, 1-10 parts of polylactic acid, and 10-40 parts of thermoplastic starch (TPS); wherein the thermoplastic starch has a thermal weight loss percentage T 100-200℃ It ranges from 10% to 40%.
[0008] In this invention, the percentage of thermal weight loss T of thermoplastic starch is controlled. 100-200℃Within a specific range, it is beneficial to control the content of plasticizer in thermoplastic starch within a suitable range, which is more conducive to the slippage and movement of starch molecular chains, so that the plasticizing properties, compatibility and processing performance of thermoplastic starch are balanced, which in turn helps to improve the puncture resistance of biodegradable compositions. The film bag material prepared by using the specific type of thermoplastic starch and biodegradable polylactic acid has a large puncture displacement and good puncture resistance.
[0009] In this invention, 50 to 89 parts of biodegradable polyester can be, for example, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 66 parts, 68 parts, 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, or any of the above values; more preferably, 55 to 79 parts, and particularly preferably 59 to 73 parts.
[0010] In this invention, the biodegradable polyester in the biodegradable composition has a mass percentage content of ≥50%, more preferably ≥55%, and particularly preferably 58.5~74.5%.
[0011] In this invention, the weight-average molecular weight (Mw) of the biodegradable polyester is 50,000 to 200,000 Da; it can be obtained by gel permeation chromatography.
[0012] In this invention, 1 to 10 parts of polylactic acid can be, for example, 1 part, 1.2 parts, 1.5 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, 5.2 parts, 5.5 parts, 5.8 parts, 6 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7 parts, 7.2 parts, 7.5 parts, 7.8 parts, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts, 10 parts, or any of the above values; more preferably, 1.6 to 8.4 parts, and particularly preferably 3.7 to 6.7 parts.
[0013] In this invention, the mass percentage of polylactic acid in the biodegradable composition is ≥1%, more preferably ≥2.3%, and particularly preferably 2.5~7.5%.
[0014] In this invention, 10 to 40 parts of thermoplastic starch can be, for example, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, or any of the above values; more preferably, 15 to 35 parts, and particularly preferably 23 to 31 parts.
[0015] In this invention, the biodegradable composition contains ≥10% by mass of thermoplastic starch, more preferably ≥15%, and particularly preferably 20-33%.
[0016] Preferably, the polylactic acid includes at least one of poly-D-lactic acid (PDLA), poly-L-lactic acid (PLLA), or a copolymer of D-lactic acid and L-lactic acid (PDLA-PLLA copolymer), more preferably a copolymer of D-lactic acid and L-lactic acid.
[0017] In this invention, the melt index of the polylactic acid is 2~50g / 10min at 190℃ and 2.16kg.
[0018] In this invention, the melt index of the polylactic acid can be measured by the ISO 1133-1:2022 standard.
[0019] In this invention, polylactic acid (PLA) can be obtained commercially or prepared using conventional methods. Exemplarily, the preparation method includes: mixing a monomer with a catalyst and reacting to obtain the PLA; the monomer includes L-lactic acid and / or D-lactic acid; the catalyst is 0.001-0.005 parts by mass of 100 parts of monomer; the catalyst includes, but is not limited to, a tin-containing catalyst (e.g., stannous octoate); the reaction includes a first stage and a second stage performed sequentially; the reaction temperature of the first stage is 130-140°C, the pressure is 1800-2600 Pa, and the time is 3.5-4.5 h; the reaction temperature of the second stage is 165-175°C, the pressure is 450-650 Pa, and the time is 5.5-6.5 h; the reaction is followed by pelleting, crystallization, and drying.
[0020] In this invention, the molar content of D-lactic acid structural units in the D-lactic acid and L-lactic acid copolymer is 1~15 mol, more preferably 1.5~12.5 mol, particularly preferably 1.8~5 mol; the total molar content of D-lactic acid structural units and L-lactic acid structural units is 100 mol.
[0021] In this invention, the percentage of mass loss due to heat of the thermoplastic starch is T. 100-200℃ The percentage is 10% to 40%, for example, it can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40% or any of the above values; preferably it is 15% to 35%.
[0022] In this invention, the percentage of mass loss due to heat of thermoplastic starch, T 100-200℃The thermogravimetric analysis (TGA) refers to the thermal weight loss ratio of thermoplastic starch in the temperature range of 100~200℃, which can be obtained by testing with a thermogravimetric analyzer (NETZCH TG209) at a heating rate of 10℃ / min.
[0023] Preferably, in the XRD pattern of the thermoplastic starch, 2 5~15 There is at least one strong peak between them, and / or, in 2 15~35 There should be at least one strong peak between them, preferably 2. 5~15 There is at least one strong peak between them and in 2 15~35 There is at least one strong peak between them.
[0024] Preferably, in the XRD pattern of the thermoplastic starch, 2 5~15 The number of strong peaks between them is 1 to 3, more preferably 1 or 2.
[0025] Preferably, in the XRD pattern of the thermoplastic starch, 2 15~35 The number of strong peaks between them is 1 to 4, more preferably 1 or 2.
[0026] More preferably, in the XRD pattern of the thermoplastic starch of the present invention, 2 5~35 Between (15.1±0.5) (17.3±0.5) () and (23.0±0.5) There are strong peaks at (10.9±0.5) locations, or at (10.9±0.5) locations. (15.1±0.5) (17.1±0.5) (18±0.5) (23±0.5) There are strong peaks at (12.9±0.5) locations, or at (12.9±0.5) locations. (18.5±0.5) () and (19.5±0.5) There are strong peaks at (6.9±0.5) locations, or at (6.9±0.5) locations. (11.9±0.5) () and (18.2±0.5) There are strong peaks everywhere.
[0027] In this invention, the XRD pattern of the thermoplastic starch was obtained by Axio Scope A1 XRD (ZEISS).
[0028] In this invention, the thermoplastic starch can be obtained commercially or prepared using conventional methods. For example, the preparation method includes: Commercially available starch is thoroughly physically mixed with an alcohol compound (15-73% by mass of starch, more preferably 24-67%), and the mixture is then fed into a twin-screw extruder through a feed port. The extruder is then hot-cut at the die surface to obtain the thermoplastic starch. The twin-screw extruder has a processing temperature of 128-172°C, a feed rate of 8-12 kg / h, and a rotation speed of 20-30 Hz. The alcohol compound includes, but is not limited to, glycerol and / or diglycerol. When the mixture of glycerol and diglycerol is selected, the mass ratio of the two is (0.5-2):1.
[0029] In this invention, the moisture content of the starch is 5-21 wt%, more preferably 8-15 wt%.
[0030] In this invention, starch with specific thermal weight loss percentage and XRD pattern can be obtained by adjusting the type and content of alcohol compounds, the moisture content of starch, and the extrusion process.
[0031] In this invention, starch with a specific moisture content can be purchased directly from the market or prepared using conventional methods. For example, the method includes the following steps: drying commercially available high-moisture starch at 60-80°C for 3-5 hours, taking samples every 10 minutes to test the moisture content until the desired moisture content is achieved; wherein, the moisture content testing method includes: weighing the sample and recording it as m0, then drying it at 60-80°C for 4-8 hours, weighing it again and recording it as m1, and calculating the moisture content as (m0-m1) / m0×100%.
[0032] In this invention, the types of starch are not limited in too much. Exemplarily, they include, but are not limited to, corn starch, potato starch, wheat starch, pea starch, etc.
[0033] Preferably, the biodegradable polyester comprises an aliphatic-aromatic copolyester.
[0034] In this invention, the aliphatic-aromatic copolyester comprises diacid residues and diol residues; the diacid residues comprise aromatic diacid residues and aliphatic diacid residues; the aromatic diacid residues comprise terephthalic acid residues and / or furanyl dicarboxylic acid residues; the aliphatic diacid residues comprise at least one of adipic acid residues, succinic acid residues, azelaic acid residues, sebacic acid residues, and brassic acid residues; and the diol residues comprise propylene glycol residues and / or butanediol residues.
[0035] It should be noted that the term "residue" refers to any organic structure introduced into the polymer molecular chain by the relevant monomer through a condensation reaction, that is, an organic structure derived from the relevant monomer; for example, a dicarboxylic acid residue refers to a structure derived from a dicarboxylic acid monomer in an aliphatic-aromatic copolyester.
[0036] In this invention, the molar ratio of the diacid residue to the diol residue is 1:1; the molar percentage of the aromatic diacid residue in the diacid residue is ≥5%, more preferably ≥30%, and particularly preferably 50~70%.
[0037] Preferably, the aliphatic-aromatic copolyester comprises any one or a combination of at least two of polybutylene adipate terephthalate (PBAT), polybutylene sebacic acid terephthalate (PBSeT), and polybutylene terephthalate succinate (PBST).
[0038] Preferably, the biodegradable composition further comprises 0.01 to 5 parts by weight of an adjuvant, for example, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 parts or any range of the above values.
[0039] Preferably, the additives include at least one of the following: opening agent, lubricant, antioxidant, compatibilizer, nucleating agent, colorant, or stabilizer.
[0040] In this invention, the additives can be selected according to actual needs, as long as they can achieve the corresponding function and do not impair the effect of this invention.
[0041] For example, the opening agent and lubricant can be used to enhance the slip properties (smoothing properties) during the extrusion process and as additives to prevent the film surfaces from adhering to each other; the opening agent and lubricant each independently include, but are not limited to, at least one of ethylene bis-stearamide (EBS), glyceryl monostearate, oleamide, and erucamide; the mass percentage of the opening agent and lubricant in the biodegradable composition can each independently be 0.1-5%.
[0042] For example, the antioxidant is an additive used to prevent decomposition by ozone or oxygen, to prevent oxidation during storage, and to prevent deterioration of the physical properties of the membrane; the antioxidant includes, but is not limited to, primary antioxidants, such as any one or a combination of at least two of 2,6-di-tert-butyl-p-cresol (BHT), 2,2'-methylene-bis(4-ethyl-6-tert-butylphenol), 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 2,2'-methylene-bis(4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis(4-methyl-6-nonylphenol), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, and pentaerythritol tetra(3,5-di-tert-butyl-4-hydroxyhydrocinnamate). The composition may contain auxiliary antioxidants, such as tri(nonylphenyl) phosphite and / or dilauryl thiodipropionate; the antioxidant content in the biodegradable composition may be 0.1-5% by mass.
[0043] Exemplarily, the compatibilizer is an additive used to impart compatibility by removing the multiphase components of biodegradable polyester, polylactic acid, and thermoplastic starch. The compatibilizer includes, but is not limited to, at least one of polyvinyl acetate (PVAc), isocyanate, polypropylene carbonate, glycidyl methacrylate, ethylene-vinyl alcohol, polyvinyl alcohol (PVA), ethylene-vinyl acetate, or maleic anhydride; the mass percentage of the compatibilizer in the biodegradable composition can be 0.1% to 5%.
[0044] For example, the nucleating agent is an additive used to supplement or change the crystalline morphology of the polymer and to increase the crystallization (solidification) rate when the polymer melt is cooled; the nucleating agent includes, but is not limited to, inorganic compounds (such as calcium carbonate, silica, kaolin, talc, barium sulfate), low molecular weight organic compounds (such as myristic acid, palmitic acid, stearic acid, behenic acid, monomethyl terephthalate, isophthalic acid), polymers (such as polyethylene glycol, polypropylene glycol, carboxyl-containing polyethylene, acrylic-styrene copolymer), etc.; the mass percentage of the compatibilizer in the biodegradable composition can be 0.1-5%.
[0045] Exemplarily, the stabilizer is an additive used to protect against oxidation and heat and to prevent color changes. The stabilizer includes, but is not limited to, at least one of trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, and phosphorous acid; the mass percentage of the stabilizer in the biodegradable composition can be 0.1-5%. In this invention, the preparation method of the biodegradable composition is not excessively limited; it can be prepared using conventional methods, including, but not limited to, the following methods: Polylactic acid and 30-70% of biodegradable polyester and optional additives are premixed at 200-500 rpm to obtain a premix. The premix and the remaining flexible biodegradable polyester are fed into the main feed port of a twin-screw extruder, and thermoplastic starch is fed into the side feed port. The mixture is melt-extruded and granulated at 150-200°C, cooled, and air-dried to obtain the biodegradable composition.
[0046] In a second aspect, the present invention provides a membrane or bag prepared using the biodegradable composition described in the first aspect.
[0047] Preferably, the membrane or bag has a thickness of 12±1μm, and the 7mm puncture displacement is 8~18mm, more preferably 8.5~12mm.
[0048] In this invention, the 7mm puncture displacement refers to the displacement when puncturing with a puncture test needle with a diameter of 7mm; the puncture displacement refers to the distance the puncture test needle moves from the moment the puncture test needle contacts the material surface during the puncture test until the material breaks, characterizing the material's ability to resist deformation during the puncture process.
[0049] The numerical range described in this invention includes not only the point values listed above, but also any point values within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values included in the range.
[0050] Compared with the prior art, the beneficial effects of the present invention are as follows: The biodegradable composition provided by this invention is made by compounding thermoplastic starch with polylactic acid and biodegradable polyester at a specific thermal weight loss percentage. The film bag material prepared from it has a large puncture displacement and good puncture resistance. Detailed Implementation
[0051] 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 in any way.
[0052] In this invention, the percentage of mass loss due to heat of thermoplastic starch, T 100-200℃ This refers to the percentage of weight loss of thermoplastic starch within a temperature range of 100~200℃, specifically calculated using the formula T. 100-200℃ =W 100-200℃ / W0 100%; of which, W 100-200℃T represents the weight loss of thermoplastic starch within the temperature range of 100–200°C, where W0 is the initial weight of the thermoplastic starch. The specific testing method includes: using a NETZCH TG209 thermogravimetric analyzer at a heating rate of 10°C / min under a nitrogen atmosphere to determine the thermogravimetric loss curve of the thermoplastic starch. Based on the thermogravimetric loss curve and calculation formula, the proportion of thermal degradation weight loss of the thermoplastic starch within the 100–200°C range is obtained and denoted as T. 100-200℃ .
[0053] In this invention, the X-ray diffraction pattern of thermoplastic starch was characterized using an Axio Scope Al XRD (ZEISS). The test conditions were: CuKα target (λ = 1.54056 Å), voltage 30 kV, current 20 mA, and scan range 5-50 Å. (2θ), scan speed 0.5 / min; observe the XRD pattern of thermoplastic starch where 2θ is 5~35 The distribution of strong peaks within the range is recorded, along with the number and location of each strong peak.
[0054] 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 shown in Tables 1-2. The specific methods for "self-made" materials are as follows.
[0055] The preparation method of PLLA-PDLA copolymer is as follows: PLLA-PDLA copolymer 1 98 parts by mass of L-type lactide (purity 99.6%), 2 parts by mass of D-type lactide (purity 99.6%), and 0.002 parts by mass of stannous octoate were mixed and reacted at a reaction temperature of 135°C and a reaction pressure of 2000 Pa for 4 hours (referred to as the first stage). Then, the mixture was reacted at a reaction temperature of 170°C and a reaction pressure of 500 Pa for 6 hours (referred to as the second stage). The mixture was then pelletized underwater, crystallized, and dried to obtain the PLLA-PDLA copolymer 1.
[0056] PLLA-PDLA copolymer 2 The preparation method of the PLLA-PDLA copolymer 1 is as follows: the mass of L-type lactide is 92 parts by mass, the mass of D-type lactide is 8 parts by mass, the pressure of the first stage reaction is 2500 Pa, the pressure of the second stage reaction is 600 Pa, and other parameters are the same as those of the PLLA-PDLA copolymer 1.
[0057] PLLA-PDLA copolymer 3 The preparation method of the PLLA-PDLA copolymer 1 is as follows: the mass of L-type lactide is 88 parts by mass, the mass of D-type lactide is 12 parts by mass, the mass of stannous octoate is 0.0035 parts by mass, the pressure of the first stage reaction is 2500 Pa, the pressure of the second stage reaction is 500 Pa, and other parameters are the same as those of the preparation method of PLLA-PDLA copolymer 1.
[0058] The preparation method of PLLA is as follows: 100 parts by mass of L-lactide (purity 99.6%) was mixed with 0.002 parts by mass of stannous octoate and reacted for 4 hours at a reaction temperature of 135°C and a reaction pressure of 2000 Pa (referred to as the first stage). Then, the mixture was reacted for 6 hours at a reaction temperature of 170°C and a reaction pressure of 500 Pa (referred to as the second stage). The mixture was then granulated underwater, crystallized, and dried to obtain the PLLA.
[0059] The preparation method of PDLA is as follows: 100 parts by mass of D-type lactide (purity of 99.7%) is mixed with 0.002 parts by mass of stannous octoate and reacted at a reaction temperature of 135℃ and a reaction pressure of 2000 Pa for 4 hours (referred to as the first stage). Then, the mixture is reacted at a reaction temperature of 170℃ and a reaction pressure of 500 Pa for 6 hours (referred to as the second stage). The mixture is then granulated underwater, crystallized, and dried to obtain the PDLA.
[0060] The preparation method of thermoplastic starch is as follows: Corn starch (derived from Henan Jindan edible corn starch, with a moisture content of 14wt%) is thoroughly physically mixed with alcohol compounds. The mixed material is then fed into a twin-screw extruder with a length-to-diameter ratio of 40:1 through the feed port, and the die surface is hot-cut to obtain the thermoplastic starch. The alcohol compounds are selected from glycerol and / or diglycerol.
[0061] In the preparation methods for TPS-1~10 and TPS-d1~d2, the specific parameters of starch moisture content, mass of alcohol compounds, type of alcohol compounds, processing temperature, feed rate, and rotation speed are as follows.
[0062] Unless otherwise specified, all starches are Henan Jindan edible corn starches; unless otherwise specified, all starches have a moisture content of 14wt%.
[0063] TPS-1: The mass of alcohol compounds is 33% of the mass of corn starch, the alcohol compound is glycerol, the processing temperature is 150℃, the feed rate is 10 kg / h, and the rotation speed is 24 Hz.
[0064] TPS-2: The mass of alcohol compounds is 25% of the mass of corn starch, the alcohol compound is glycerol, the processing temperature is 150℃, the feed rate is 10kg / h, and the rotation speed is 24 Hz.
[0065] TPS-3: The mass of alcohol compounds is 66.7% of the mass of corn starch. The alcohol compounds are a mixture of glycerol and diglycerol in a mass ratio of 1:1. The processing temperature is 150℃, the feed rate is 10kg / h, and the rotation speed is 24Hz.
[0066] TPS-4: The mass of alcohol compounds is 17.6% of the mass of corn starch, the alcohol compound is glycerol, the processing temperature is 150℃, the feed rate is 10kg / h, and the rotation speed is 24Hz.
[0067] TPS-5: The mass of alcohol compounds is 72.4% of the mass of corn starch, the alcohol compound is diglycerol, the processing temperature is 150℃, the feeding rate is 10kg / h, and the rotation speed is 24Hz.
[0068] TPS-6: The mass of alcohol compounds is 33% of the mass of corn starch, the alcohol compound is glycerol, the processing temperature is 170℃, the feed rate is 10kg / h, and the rotation speed is 24Hz.
[0069] TPS-7: The mass of alcohol compounds is 33% of the mass of corn starch, the alcohol compound is glycerol, the processing temperature is 140℃, the feed rate is 10kg / h, and the rotation speed is 24Hz.
[0070] TPS-8: The mass of alcohol compounds is 33% of the mass of corn starch, the alcohol compound is glycerol, the processing temperature is 130℃, the feed rate is 10kg / h, and the rotation speed is 24Hz.
[0071] TPS-9: The difference between it and TPS-1 is that corn starch is replaced with potato starch (Beidahuang Company, with a moisture content of 14%), while other parameters are the same as TPS-1.
[0072] TPS-10: The difference between it and TPS-1 is that the moisture content of the corn starch is 20%, while the other parameters are the same as those of TPS-1.
[0073] TPS-d1: The mass of alcohol compounds is 33% of the mass of corn starch. The alcohol compounds are a mixture of glycerol and diglycerol in a mass ratio of 0.5:1. The processing temperature is 150℃, the feed rate is 10 kg / h, and the rotation speed is 80 Hz.
[0074] TPS-d2: The mass of alcohol compounds is 33% of the mass of corn starch, the alcohol compound is glycerol, the processing temperature is 150℃, the feed rate is 1kg / h, and the rotation speed is 24Hz.
[0075] Opening agent: Glyceryl monostearate, Shandong Binsheng Company, Glyceryl monostearate ST-101.
[0076] Lubricant: Erucamide, Croda Chemical (Sichuan) Co., Ltd. Erucamide: OPTISLIP ER-CH-BE-(SI).
[0077] Table 1 Table 2 Examples 1-19, Comparative Examples 1-2 Examples 1-19 and Comparative Examples 1-2 each provide a biodegradable composition. The formulations of the biodegradable compositions are shown in Tables 3-5 by weight. Wherein, " / " indicates that the component is not in the formulation. The preparation method of the biodegradable composition includes: premixing polylactic acid and 50% of the formulation amount of biodegradable polyester and optional other additives at 300 rpm to obtain a premix; feeding the premix and the remaining polyester into the main feed port of a twin-screw extruder, feeding thermoplastic starch into the side feed port, melt extruding and granulating at 180°C, cooling and air drying to obtain the biodegradable composition.
[0078] Table 3 Table 4 Table 5 Performance testing The biodegradable compositions provided in the examples and comparative examples were first blown into a film with a thickness of 12±1μm using a blown film machine, and then bagged using a bag-cutting machine. Their puncture resistance was then tested. The specific process was as follows: the blown film temperature was 150℃ and the blown film speed was 20kg / h.
[0079] (1) Puncture resistance: The puncture resistance of the film bag was tested using a universal film testing machine. According to GB / T21302-2007 standard, the film was fixed on the universal film testing machine, and a puncture test needle with a diameter of 7 mm was used. The test was carried out at a speed of 50 mm / min until the film ruptured. The distance the puncture test needle moved at this time was recorded. The average value was taken after 5 parallel tests.
[0080] The specific test results are shown in Table 6.
[0081] Table 6 As shown in Table 6, the biodegradable composition provided by this invention, which is a compound of a specific type of polylactic acid with flexible biodegradable and thermoplastic starch, produces a film bag material with good puncture resistance; the 7mm puncture displacement of the film bag material... 8mm.
[0082] As can be seen from Examples 1, 11-14, and Comparative Examples 1 and 2, the T of the thermoplastic starch... 100-200℃ Within a certain range, it is beneficial to further improve the puncture resistance of the membrane bag material.
[0083] As can be seen from Examples 1 and 15-17, using thermoplastic starch with a specific structure, i.e. thermoplastic starch with a specific XRD pattern, is beneficial to further improve the puncture resistance of the film bag material.
[0084] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A biodegradable composition, characterized in that, The biodegradable composition comprises, by weight, 50-89 parts of biodegradable polyester, 1-10 parts of polylactic acid and 10-40 parts of thermoplastic starch; The percentage of mass loss due to heat of the thermoplastic starch, T 100-200℃ It ranges from 10% to 40%.
2. The biodegradable composition according to claim 1, characterized in that, The polylactic acid includes at least one of poly-D-lactic acid, poly-L-lactic acid, or a copolymer of D-lactic acid and L-lactic acid, more preferably a copolymer of D-lactic acid and L-lactic acid.
3. The biodegradable composition according to claim 1 or 2, characterized in that, The percentage of mass loss due to heat of the thermoplastic starch, T 100-200℃ It ranges from 15% to 35%.
4. The biodegradable composition according to any one of claims 1 to 3, characterized in that, In the XRD pattern of the thermoplastic starch, 2 5~15 There is at least one strong peak between them, and / or, in 2 15~35 There should be at least one strong peak between them, preferably 2. 5~15 There is at least one strong peak between them and in 2 15~35 There is at least one strong peak between them.
5. The biodegradable composition according to any one of claims 1 to 4, characterized in that, In the XRD pattern of the thermoplastic starch, 2 5~15 The number of strong peaks between them is 1 to 3, more preferably 1 or 2; Preferably, in the XRD pattern of the thermoplastic starch, 2 15~35 The number of strong peaks between them is 1 to 4, more preferably 1 or 2.
6. The biodegradable composition according to any one of claims 1 to 5, characterized in that, The biodegradable polyester includes aliphatic-aromatic copolyesters; Preferably, the aliphatic-aromatic copolyester comprises any one or a combination of at least two of polybutylene adipate, polybutylene sebacate, and polybutylene succinate.
7. The biodegradable composition according to any one of claims 1 to 6, characterized in that, The biodegradable composition further includes 0.01 to 5 parts by weight of adjuvants.
8. The biodegradable composition according to claim 7, characterized in that, The additives include at least one of the following: opening agent, lubricant, antioxidant, compatibilizer, nucleating agent, colorant, or stabilizer.
9. A film or bag, characterized in that, The membrane or bag is prepared using the biodegradable composition according to any one of claims 1 to 8.
10. The membrane or bag according to claim 9, characterized in that, With a thickness of 12±1μm, the membrane or bag has a 7mm puncture displacement of 8~18mm, more preferably 8.5~12mm.