Starch-based biodegradable composition and preparation method therefor

Abstract

The present invention relates to a starch-based biodegradable composition having excellent mechanical properties and durability and to a biodegradable film prepared using same, the starch-based biodegradable composition comprising a thermoplastic starch, a biodegradable resin, a first compatibilizer, a second compatibilizer, and a lubricant, wherein the first compatibilizer is an epoxy compound, and the second compatibilizer is a tricarboxylic acid.

Description

Starch-based biodegradable composition and method for producing the same

[0001] The present invention relates to a starch-based biodegradable composition comprising an epoxy compound and a carboxylic acid as a compatibilizer, and a starch-based biodegradable film having improved durability and mechanical properties manufactured using the same.

[0002] Biodegradable polymers can be categorized into petroleum-derived and bio-derived, with relatively high interest in eco-friendly and renewable bio-derived polymers. Polymers that are fully biodegradable in the global environment contain functional groups in their backbone structure that enable microbial decomposition. Among these, polyester polymers are the most widely studied due to their excellent processability and easy control of biodegradation properties. For example, polylactic acid (PLA), a bio-derived biodegradable polymer synthesized from lactic acid obtained by fermenting corn starch, has a global market size of approximately 100,000 tons and is widely used in general plastic applications such as food packaging and containers, and electronic device cases. However, PLA resins have poor formability, mechanical strength, and heat resistance, making thin-film products susceptible to breakage. Furthermore, their low temperature resistance leads to deformation of the molded product when the external temperature increases.

[0003] In addition, polybutylene adipate-co-terephthalate (PBAT), the most widely used petroleum-derived biodegradable polyester polymer, is a copolymer resin containing aliphatic and aromatic groups. Although it has relatively excellent mechanical properties and various processability, it has the disadvantages of low structural strength and high manufacturing cost. In order to improve the low physical properties of the above-mentioned polyester resin and reduce the high manufacturing cost compared to the manufacturing cost of non-biodegradable polymers, various research methods are being proposed to make composite materials by including biomass, an eco-friendly material.

[0004] Accordingly, research has been conducted to reduce costs and improve biodegradability by incorporating starch, a representative plant-based biomass, into biodegradable resins. However, starch-based materials generally experience a decline in mechanical strength, water solubility, and discoloration due to decomposition during processing or heat. Carbonization of starch and starch-derived polysaccharides are identified as the causes of these problems. Therefore, when applying starch to biodegradable resins, the amount of starch added is limited due to its unique hydrophilicity and reduced processability. Furthermore, starch has poor miscibility with biodegradable resins, and the application of starch reduces bonding strength, resulting in films containing starch with low mechanical properties and durability. Furthermore, these films present several problems, including a decrease in strength due to moisture absorption.

[0005] To address this issue, various attempts have been made to impart thermoplastic properties to starch by reacting it with plasticizers and to manufacture biodegradable composite materials by adding compatibilizers. However, these efforts have yet to meet industry standards. Therefore, there is a growing need for the development of eco-friendly materials that simultaneously satisfy biodegradability, mechanical properties, and durability.

[0006] The purpose of the present invention is to provide a starch-based biodegradable composition including a compatibilizer capable of forming an ester bond with starch to improve the mechanical properties of a biodegradable composite material, and a method for producing the same.

[0007] Another object of the present invention is to provide an eco-friendly starch-based biodegradable composition having excellent mechanical properties such as tensile strength and elongation, manufactured by mixing two types of commercializing agents with different functions, and a biodegradable compound and film manufactured using the same.

[0008] One aspect of the present invention provides a starch-based biodegradable composition comprising thermoplastic starch, a biodegradable resin, a first compatibilizer, a second compatibilizer, and a lubricant, wherein the starch-based biodegradable composition comprises 0.1 to 2.0 parts by weight of the first compatibilizer, 0.1 to 2.0 parts by weight of the second compatibilizer, and 0.1 to 2.0 parts by weight of the lubricant, based on 100 parts by weight of a mixture of the thermoplastic starch and the biodegradable resin, wherein the first compatibilizer is an epoxy compound, and the second compatibilizer is a tricarboxylic acid.

[0009] In an embodiment, the first commercializing agent may be a chain extender, for example, a cardanol epoxy compound.

[0010] According to an embodiment, the second commercializing agent may be citric acid.

[0011] According to an embodiment, the mixing ratio of the thermoplastic starch and the biodegradable resin may be 20 to 40 parts by weight: 60 to 80 parts by weight.

[0012] According to an embodiment, the thermoplastic starch is prepared by reacting starch with a plasticizer, and may further include a compatibilizer and a reaction initiator.

[0013] According to an embodiment, the starch usable in the thermoplastic starch may be at least one selected from the group consisting of corn starch, waxy corn starch, rice starch, potato starch, tapioca starch, wheat starch, sweet potato starch, or modified starches thereof, but is not limited thereto.

[0014] According to an embodiment, the biodegradable resin usable in the starch-based biodegradable composition may be at least one selected from the group consisting of polybutylene adipate terephthalate, polylactic acid, polycaprolactone, polybutylene succinate, polyglycolic acid, polyhydroxyalkanoate, polyhydroxybutyrate, copolymers thereof, and mixtures thereof, but is not limited thereto.

[0015] According to an embodiment, the active agent usable in the starch-based biodegradable composition may be at least one selected from the group consisting of calcium stearate, glycerol monostearate, zinc stearate, ethylene bis stearamide, fatty acid ester, and magnesium stearate, but is not limited thereto.

[0016] Another aspect of the present invention provides a method for producing a starch-based biodegradable composition, comprising the steps of mixing thermoplastic starch, a biodegradable resin, a first compatibilizer, a second compatibilizer, and a lubricant; and the steps of introducing the mixture into an extruder, reacting the mixture, and then extruding the mixture, wherein the first compatibilizer is an epoxy compound and the second compatibilizer is a tricarboxylic acid. The first compatibilizer may be a cardanol epoxy compound, and the second compatibilizer may be citric acid, but is not limited thereto.

[0017] According to an embodiment, the reaction temperature of the extruder may be in the range of 150 to 200°C, but is not limited thereto.

[0018] According to an embodiment, the step of cooling and drying the extruded composition after high-temperature reaction in the extruder to pelletize it may be further included.

[0019] The tensile strength of a compound manufactured using the starch-based biodegradable composition according to the embodiment may be in the range of 20 to 80 MPa.

[0020] The notched impact strength of the compound manufactured using the starch-based biodegradable composition according to the embodiment is 2.0 to 15 KJ / m 2 It could be a range.

[0021] Another aspect of the present invention provides a biodegradable film manufactured using the starch-based biodegradable composition.

[0022] According to the present invention, when a starch-based biodegradable composition is prepared by using a carboxylic acid such as citric acid as a compatibilizer together with an epoxy compound as a chain extender, an ester bond is additionally induced between the OH group of the starch and the carboxyl group of the compatibilizer, thereby forming a new network between molecules, thereby improving the mechanical strength of the biodegradable composite material and stabilizing its quality.

[0023] The following examples show that the mechanical properties, such as tensile strength, of a biodegradable compound manufactured using citric acid as a reactive compatibilizer together with a cardanol epoxy compound as a chain extender are significantly improved.

[0024] The present invention will be described in more detail below with reference to examples. However, the following examples are provided for illustrative purposes only to aid understanding of the present invention and are not intended to limit its scope. It should be understood that the present invention is susceptible to various modifications and implementations in various different forms, and encompasses all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0025] Additionally, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0026] According to one embodiment of the present invention, a starch-based biodegradable composition comprises thermoplastic starch, a biodegradable resin, a first compatibilizer, a second compatibilizer, and a lubricant, and comprises 0.1 to 2.0 parts by weight of the first compatibilizer, 0.1 to 2.0 parts by weight of the second compatibilizer, and 0.1 to 2.0 parts by weight of the lubricant, based on 100 parts by weight of a mixture of the thermoplastic starch and the biodegradable resin, wherein the first compatibilizer may be an epoxy compound, and the second compatibilizer may be a tricarboxylic acid.

[0027] The first commercializing agent may be a chain extender, and may be an epoxy compound, such as a cardanol epoxy compound.

[0028] The second commercializing agent may be citric acid.

[0029] When a starch-based biodegradable composition is manufactured using a chain extender such as an epoxy compound and a carboxylic acid such as citric acid as a compatibilizer, an ester bond is additionally induced between the OH group of the starch and the carboxyl group of the compatibilizer, forming a new network between molecules. Accordingly, the mechanical strength of the biodegradable composite material is improved, thereby stabilizing its quality.

[0030] Through the following examples, it can be seen that the mechanical properties, such as tensile strength, of a biodegradable compound manufactured by mixing a cardanol epoxy compound as a chain extender and citric acid as a reactive compatibilizer are significantly improved.

[0031] According to one embodiment of the present invention, thermoplastic starch is starch prepared by reacting starch with a plasticizer, and may further include a reaction initiator, a compatibilizer, or an additive.

[0032] Starch usable as thermoplastic starch may be one or more selected from the group consisting of corn starch, waxy corn starch, rice starch, potato starch, tapioca starch, wheat starch, sweet potato starch, or modified starches thereof, but is not limited thereto.

[0033] The plasticizer usable in the thermoplastic starch may be, for example, one or more selected from the group consisting of glycerin, ethylene glycol, sorbitol, and pentaerythritol, but is not limited thereto. It is preferable to use the plasticizer in an amount of 1 to 30 parts by weight based on the total weight of the thermoplastic starch. If the content of the plasticizer is less than the above range, the plasticization reaction will not occur, and if it exceeds the content, excessive plasticization will occur, resulting in a problem of a paste-like state.

[0034] Thermoplastic starch may further include a compatibilizer in addition to starch and a plasticizer. For example, the compatibilizer may be selected from the group consisting of maleic anhydride, fumaric anhydride, acetylenedicarboxylic anhydride, glutaconic anhydride, 2-decenedioic anhydride, traumatic anhydride, muconic anhydride, glutinic anhydride, citraconic anhydride, mesaconic anhydride, itaconic anhydride, maleic acid, fumaric acid, acetylenedicarboxylic acid, glutaconic acid, 2-decenedioic acid, traumatic acid, muconic acid, glutinic acid, citraconic acid, mesaconic acid, and itaconic acid, but is not particularly limited thereto. It is preferable to use the compatibilizer in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of thermoplastic starch.

[0035] After manufacturing or purchasing thermoplastic starch and preparing it, a biodegradable resin, a compatibilizer, and a lubricant are mixed and reacted at high temperature in an extruder to produce a starch-based biodegradable composition.

[0036] The biodegradable resin may be selected from the group consisting of, for example, polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene succinate (PBS), polycaprolactone (PCL), polyglycolic acid (PGA), polyhydroxy alkanoate (PHA), polyhydroxybutyrate (PHB), copolymers thereof, and mixtures thereof, but is not limited thereto. The blending ratio of the thermoplastic starch and the biodegradable resin may be 20 to 40 parts by weight: 60 to 80 parts by weight.

[0037] The active agent usable in the starch-based biodegradable composition may be at least one selected from the group consisting of calcium stearate, glycerol monostearate, zinc stearate, ethylene bis stearamide, fatty acid ester, and magnesium stearate, but is not limited thereto.

[0038] It is preferable to use the lubricant in an amount of 0.1 to 2 parts by weight for 100 parts by weight of the mixture of the thermoplastic starch and biodegradable resin.

[0039] Lubricants are used to improve dispersion and processability during compound manufacturing. If lubricants are used in amounts below the above range, processability is inadequate, resulting in reduced dispersibility and increased extrusion load. Furthermore, if lubricants are used in amounts exceeding the above range, the physical properties of the extrudate may be seriously degraded.

[0040] A method for producing a starch-based biodegradable composition according to one embodiment of the present invention comprises the steps of mixing thermoplastic starch, a first compatibilizer, a second compatibilizer, a biodegradable resin, and a lubricant; and the steps of introducing the mixture into an extruder, reacting the mixture, and then extruding the mixture. The first compatibilizer may be an epoxy compound, such as a cardanol epoxy compound, which is a chain extender, and the second compatibilizer may be a tricarboxylic acid, such as citric acid.

[0041] The starch-based biodegradable composition according to the present invention can be manufactured using a twin-screw extruder or the like, and the reaction temperature of the extruder may range from 150 to 200°C, but is not limited thereto. The process may further include a step of cooling and drying the starch-based biodegradable composition extruded after a high-temperature reaction in the extruder to pelletize it. A biodegradable composition in pellet form is preferable because it provides convenience in product mixing and processing.

[0042] A biodegradable film manufactured using the starch-based biodegradable composition according to the present invention has the advantages of excellent biodegradability and mechanical properties. The tensile strength of the compound manufactured using the starch-based biodegradable composition according to the present invention may be in the range of 20 to 80 MPa, and the notched impact strength may be in the range of 2.0 to 15 KJ / m. 2 It could be a range.

[0043] In this way, the biodegradable injection molded article manufactured using the starch-based biodegradable composition according to the present invention has excellent mechanical strength such as tensile strength and impact strength and durability, and thus can be used in various products such as food containers, trays, packaging containers, household goods, and plastic bottles.

[0044] The present invention is described in more detail below through examples and comparative examples, but these are illustrative and should not be construed as limiting the scope of the present invention.

[0045] <Example 1>

[0046] A) Production of thermoplastic starch

[0047] 85 parts by weight of corn starch and 15 parts by weight of glycerin were mixed and placed in a heating mixer. High-speed mixing was performed using a shovel mixer, and the uniformly mixed composition was placed in a twin-screw extruder. The extruder barrel temperature was 140 to 145 ° C, and the main screw speed was 300 rpm. The extrudate was pelletized to produce thermoplastic starch.

[0048] B) Preparation of starch-based biodegradable composition

[0049] After mixing 20 parts by weight of the above thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate) and 1 part by weight of 2,3-Epoxypropyl methacrylate were mixed based on 100 parts by weight of the above mixture.

[0050] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0051] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0052] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210°C to 220°C.

[0053] C) Manufacturing of biodegradable films

[0054] The above biodegradable composition was fed into a film forming machine to produce a biodegradable film with an average thickness of 25-35㎛. The film forming machine temperature was 150 to 170°C, and the raw material feeding speed was 700 to 800 rpm.

[0055] <Example 2>

[0056] A) Production of thermoplastic starch

[0057] The method for producing thermoplastic starch is the same as in Example 1.

[0058] B) Preparation of biodegradable resin composition

[0059] After mixing 20 parts by weight of the above thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate) and 1 part by weight of Cardanol epoxy were mixed based on 100 parts by weight of the above mixture.

[0060] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0061] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0062] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0063] C) Manufacturing of biodegradable films

[0064] The method for manufacturing a biodegradable film is the same as in Example 1.

[0065] <Example 3>

[0066] A) Production of thermoplastic starch

[0067] The method for producing thermoplastic starch is the same as in Example 1.

[0068] B) Preparation of starch-based biodegradable composition

[0069] After mixing 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate) and 1 part by weight of 3-Aminopropyltrimethoxysilane were mixed.

[0070] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0071] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0072] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0073] C) Manufacturing of biodegradable films

[0074] The method for manufacturing a biodegradable film is the same as in Example 1.

[0075] <Example 4>

[0076] A) Production of thermoplastic starch

[0077] The method for producing thermoplastic starch is the same as in Example 1.

[0078] B) Preparation of starch-based biodegradable composition

[0079] After mixing 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate) and 1 part by weight of maleic anhydride were mixed.

[0080] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0081] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0082] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0083] C) Manufacturing of biodegradable films

[0084] The method for manufacturing a biodegradable film is the same as in Example 1.

[0085] <Example 5>

[0086] A) Production of thermoplastic starch

[0087] The method for producing thermoplastic starch is the same as in Example 1.

[0088] B) Preparation of starch-based biodegradable composition

[0089] After mixing 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate) and 1 part by weight of citric acid were mixed.

[0090] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0091] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0092] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0093] C) Manufacturing of biodegradable films

[0094] The method for manufacturing the biodegradable film is the same as in Example 1.

[0095] <Example 6>

[0096] A) Production of thermoplastic starch

[0097] The method for producing thermoplastic starch is the same as in Example 1.

[0098] B) Preparation of starch-based biodegradable composition

[0099] After mixing 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate), 0.5 parts by weight of Cardanol Epoxy, and 0.5 parts by weight of Maleic anhydride were mixed.

[0100] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0101] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0102] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0103] C) Manufacturing of biodegradable films

[0104] The method for manufacturing the biodegradable film is the same as in Example 1.

[0105] <Example 7>

[0106] A) Production of thermoplastic starch

[0107] The method for producing thermoplastic starch is the same as in Example 1.

[0108] B) Preparation of starch-based biodegradable composition

[0109] After mixing 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate), 0.5 parts by weight of Cardanol Epoxy, and 0.5 parts by weight of Citric acid were mixed.

[0110] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0111] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0112] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0113] C) Manufacturing of biodegradable films

[0114] The method for manufacturing a biodegradable film is the same as in Example 1.

[0115] <Example 8>

[0116] A) Production of thermoplastic starch

[0117] The method for producing thermoplastic starch is the same as in Example 1.

[0118] B) Preparation of starch-based biodegradable composition

[0119] After mixing 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate), 0.5 parts by weight of 3-Aminopropyltrimethoxysilane, and 0.5 parts by weight of maleic anhydride were mixed.

[0120] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0121] The extrudate extruded through the extruder die was water-cooled and pelletized by installing a water channel. The pellets were dried at 60°C for more than 24 hours to obtain a biodegradable injection-type material.

[0122] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0123] C) Manufacturing of biodegradable films

[0124] The method for manufacturing a biodegradable film is the same as in Example 1.

[0125] <Example 9>

[0126] A) Production of thermoplastic starch

[0127] The method for producing thermoplastic starch is the same as in Example 1.

[0128] B) Preparation of starch-based biodegradable composition

[0129] After mixing 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA, 0.2 parts by weight of a lubricant (Ca-stearate), 0.5 parts by weight of 3-Aminopropyltrimethoxysilane, and 0.5 parts by weight of citric acid were mixed.

[0130] The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0131] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0132] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0133] C) Manufacturing of biodegradable films

[0134] The method for manufacturing a biodegradable film is the same as in Example 1.

[0135] <Comparative Example 1>

[0136] A) Production of thermoplastic starch

[0137] The method for producing thermoplastic starch is the same as in Example 1.

[0138] B) Preparation of starch-based biodegradable composition

[0139] 20 parts by weight of thermoplastic starch, 80 parts by weight of PLA, and 0.2% of a lubricant (Ca-stearate) were mixed. The uniformly mixed composition was fed into a twin-screw extruder. The extruder barrel temperature was 170 to 190°C, and the main screw speed was 180 to 200 rpm.

[0140] The extrudate extruded through the extruder die was water-cooled and pelletized through a water channel. The pellets were dried at 60°C for more than 24 hours to produce a biodegradable composition for injection molding.

[0141] The above biodegradable composition was introduced into a physical specimen making machine to manufacture a biodegradable composite injection specimen, and the temperature of the injection molding machine was 210 to 220°C.

[0142] C) Manufacturing of biodegradable films

[0143] The method for manufacturing a biodegradable film is the same as in Example 1.

[0144] <Physical property evaluation>

[0145] The mechanical properties of the starch-based biodegradable composition (compound) specimens manufactured in the above examples and comparative examples were measured and are shown in [Table 1] below.

[0146] The tensile strength and elongation were determined using the UTM tensile test method for each specimen, and the impact strength was measured using the Notched IZOD impact test method.

[0147] The above tensile strength specimens were manufactured according to ASTM D638 V standard and the tensile strength and elongation were measured using UTM, and the impact strength was measured using the notched Izod impact test method for 1 / 8 inch thick specimens according to ASTM D256 standard.

[0148] Comparison Example 1 Example 1 Example 2 Example 3 Example 4 Total content of compatibilizer (%) - 1.0 1.0 1.0 1.0 Compatibilizer 2,3-Epoxypropyl methacrylate - 1.0 ---Cardanol Epoxy - 1.0 ---3-Aminopropyltrimethoxysilane - 1.0 -Maleic anhydride---- 1.0 Citric acid----- Result MFI (g / 10min, 190 ℃) 7.6 9.8 18.8 3 7.2 16.0 Tensile strength (MPa) 50.2 5 1.2 5 1.0 5 6.9 5 2.6 Tensile strength increase rate (%) - 1.9 9 1.5 9 13.3 5 4.78 Elongation (%) 0.7 0.6 0.5 0.4 0.6 Notched impact strength (KJ / m2)4.74.53.82.84.0

[0149] ClassificationExample 5Example 6Example 7Example 8Example 9Compatibilizer Total content (%) 1.0 1.0 1.0 1.0 1.0 Compatibilizer 2,3-Epoxypropyl methacrylate-----Cardanol Epoxy-0.5 0.5--3-Aminopropyltrimethoxysilane---0.5 0.5 Maleic anhydride-0.5-0.5-Citric acid 1.0-0.5-0.5 Result MFI (g / 10min, 190 ℃) 12.6 26.0 16.6 23.3 5 3.0 Tensile strength (MPa) 61.1 5 0.8 6 3.8 4 7.2 5 0.9 Tensile strength Increase rate (%) 21.7 11.20 27.09-5.98 1.39 Elongation (%) 0.7 0.40.70.40.5 Notch impact strength (KJ / m2) 4.8 4.7 4.5 4.5 4.4

[0150] As shown in Tables 1 and 2 above, it was confirmed that the biodegradable compound manufactured using a cardanol epoxy compound as a chain extender and citric acid (citric acid) as a reactive compatibilizer according to Example 7 had a tensile strength improved by 27% or more compared to the compound according to the comparative example, and also had excellent elongation and notched impact strength.

Claims

1. A starch-based biodegradable composition comprising thermoplastic starch, a biodegradable resin, a first compatibilizer, a second compatibilizer, and an activator, With respect to 100 parts by weight of the mixture of the thermoplastic starch and the biodegradable resin, 0.1 to 2.0 parts by weight of the first compatibilizer, 0.1 to 2.0 parts by weight of the second compatibilizer, and 0.1 to 2.0 parts by weight of the lubricant are included. A starch-based biodegradable composition, wherein the first compatibilizer is an epoxy compound and the second compatibilizer is a tricarboxylic acid.

2. In paragraph 1, A starch-based biodegradable composition wherein the first compatibilizer is a cardanol epoxy compound and the second compatibilizer is citric acid.

3. In paragraph 1, A starch-based biodegradable composition, wherein the biodegradable resin is at least one selected from the group consisting of polybutylene adipate terephthalate, polylactic acid, polycaprolactone, polybutylene succinate, polyglycolic acid, polyhydroxy alkanoate, polyhydroxybutyrate, copolymers thereof, and mixtures thereof.

4. In paragraph 1, A starch-based biodegradable composition, wherein the active agent is at least one selected from the group consisting of calcium stearate, glycerol monostearate, zinc stearate, ethylene bis stearamide, fatty acid ester, and magnesium stearate.

5. In paragraph 1, A starch-based biodegradable composition, wherein the mixing ratio of the thermoplastic starch and the biodegradable resin is 20 to 40 parts by weight: 60 to 80 parts by weight.

6. A step of mixing thermoplastic starch, biodegradable resin, first compatibilizer, second compatibilizer and activator; and It includes a step of putting the above mixture into an extruder, reacting it, and then extruding it. A method for producing a starch-based biodegradable composition, characterized in that the first compatibilizer is an epoxy compound and the second compatibilizer is a tricarboxylic acid.

7. In paragraph 6, A method for producing a starch-based biodegradable composition, wherein the first compatibilizer is a cardanol epoxy compound and the second compatibilizer is citric acid.

8. In paragraph 6, A method for producing a starch-based biodegradable composition, wherein the reaction temperature of the extruder is in the range of 150 to 200°C.

9. A compound manufactured using a starch-based biodegradable composition according to Article 1, having a tensile strength of 20 to 80 MPa and a notched impact strength of 2.0 to 15 KJ / m 2 Biodegradable compounds in the range.

10. A biodegradable film manufactured using the starch-based biodegradable composition according to Article 1.