Biodegradable resin composition comprising compatibilizer and essential oil, and film manufactured using same

Abstract

The present invention relates to: a starch-based biodegradable resin composition having improved odor, water leaching, and mechanical strength as a result of simultaneously using an essential oil masking agent and a compatibilizer that reacts with a hydroxy group of starch; and a biodegradable film using same.

Description

Biodegradable resin composition comprising a compatibilizer and essential oils and a film manufactured using the same

[0001] The present invention relates to a starch-based biodegradable resin composition with improved odor, water immersion elution characteristics, and mechanical strength by simultaneously introducing a compatibilizer that reacts with the hydroxyl group of starch and an essential oil masking agent, and a biodegradable film using the same.

[0002] Biodegradable polymers can be classified into petroleum-derived and bio-derived biodegradable polymers, with relatively high interest in eco-friendly and renewable bio-derived polymers. Polymers that exhibit complete biodegradability within the global environment contain functional groups in their main chain structure that allow for decomposition by microorganisms. Among these, polyester-based polymers are the most extensively studied due to their excellent processability and ease of controlling biodegradation properties. For example, polylactic acid (PLA) is a bio-derived biodegradable polymer synthesized based on lactic acid obtained by fermenting corn starch; it forms a global market of approximately 100,000 tons and is being applied to general plastic sectors such as food packaging, containers, and electronic product cases. However, polylactic acid resins have disadvantages, such as poor moldability, mechanical strength, and heat resistance, which cause thin-film products to break easily, and low temperature resistance, leading to deformation of molded products when external temperatures rise.

[0003] Furthermore, polybutylene adipate terephthalate, the most widely used petroleum-derived biodegradable polyester polymer currently, is a copolymer resin containing aliphatic and aromatic groups. While it possesses relatively excellent mechanical properties and diverse processability, it has the disadvantages of weak structural strength and high manufacturing costs. To improve the poor properties of the aforementioned polyester resin and reduce the high manufacturing costs compared to non-biodegradable polymers, various research methods are being proposed to form composite materials by incorporating biomass, an eco-friendly material.

[0004] Accordingly, development has been underway to reduce costs and improve biodegradability by mixing starch, a representative plant-based biomass, into biodegradable resins. However, when starch is generally applied to biodegradable resins, there have been problems where the amount of starch added is limited and product quality deteriorates due to the degradation of physical properties caused by starch's inherent hydrophilicity and reduced processability.

[0005] To address these issues, various attempts have been made to manufacture composite materials by reacting starch with plasticizers to impart thermoplasticity and mixing it with biodegradable resins; however, these methods have not yet met industrial standards. Therefore, there is a need for the development of eco-friendly materials that can simultaneously satisfy biodegradability, mechanical properties, and economic feasibility.

[0006] The problem that the present invention aims to solve is to provide a starch-based biodegradable resin composition with improved odor, water immersion leaching characteristics, and mechanical strength, and a biodegradable film using the same.

[0007] One aspect of the present invention provides a biodegradable resin composition comprising, based on 100 parts by weight of the biodegradable resin composition, 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil.

[0008] According to the embodiments, the compatibilizer may be a carbodiimide-based compatibilizer, and may be one or more selected from, for example, polymeric carbodiimide, monomeric carbodiimide, linear aromatic carbodiimide, sterically hindered aromatic carbodiimide, aliphatic carbodiimide, cycloaliphatic carbodiimide, functionalized carbodiimide, and heteroaromatic carbodiimide, but is not limited thereto.

[0009] According to the embodiments, the polymeric carbodiimide may specifically be one or more selected from aliphatic polymeric carbodiimide, aromatic polymeric carbodiimide, and hybrid polymeric carbodiimide, but is not limited thereto.

[0010] According to the examples, the essential oil may be selected from one or more of eucalyptol, vanillin, lavender, lemongrass, and orange oil, but is not limited thereto.

[0011] According to the examples, the biodegradable resin may be selected from one or more of polybutylene adipate terephthalate, polylactic acid, polycaprolactone, polybutylene succinate, polyglycolic acid, polyhydroxyalkanoate, polyhydroxybutylate, and copolymers thereof, but is not limited thereto.

[0012] According to the examples, the inorganic filler may be selected from one or more of calcium carbonate, talc, kaolin, barium sulfate, wollastonite, glass fiber, and cellulose microfiber, but is not limited thereto.

[0013] According to the examples, the lubricant may be selected from one or more of calcium stearate, glycerin monostearate, zinc stearate, magnesium stearate, ethylene bisstearamide, fatty acid esters, and waxes, but is not limited thereto.

[0014] Another aspect of the present invention provides a method for manufacturing a biodegradable film comprising the steps of: feeding 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil into an extruder to produce pellets; and feeding the pellets into a film forming machine to produce a film.

[0015] In the method for manufacturing the above biodegradable film, the compatibilizer is polymeric carbodiimide, and the essential oil may be one or more selected from eucalyptol, vanillin, lavender, lemongrass, and orange oil.

[0016] According to the example, the temperature of the extruder may be in the range of 150 to 180°C, and the temperature of the film forming machine may be in the range of 160 to 230°C.

[0017] Another aspect of the present invention provides a film prepared using a biodegradable resin composition comprising, based on 100 parts by weight of the biodegradable resin composition, 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil.

[0018] According to the example, the tensile strength of the biodegradable film may be in the range of 20 to 55 MPa.

[0019] According to the example, the biodegradable film may have a water immersion release rate of 10% or less of the compound measured after immersion in water for 24 hours at room temperature.

[0020] The present invention provides a starch-based biodegradable resin composition comprising a compatibilizer that reacts with the hydroxyl group of starch and an essential oil masking agent, and a biodegradable film manufactured using the same.

[0021] The biodegradable composite material composition according to the present invention comprises thermoplastic starch, biodegradable resin, inorganic filler, lubricant, compatibilizer, and essential oil.

[0022] It is preferable to use carbodiimide-based materials as compatibilizers. Carbodiimide-based compatibilizers react with the hydroxyl groups of starch to increase interfacial adhesion and stiffness, thereby enhancing the mechanical properties of starch-based composite materials.

[0023] Furthermore, the use of carbodiimide-based compatibilizers reduces the water absorption rate of starch-based biodegradable resin compositions and films due to the reduction of hydroxyl groups. Additionally, carbodiimide-based compatibilizers can restore physical properties by inhibiting the activity of carboxyl groups and reducing acid content, thereby preventing the degradation of polyester chains through crosslinking; moreover, the ester bonds have the effect of improving hydrolytic resistance and adhesion to biodegradable resins.

[0024] When essential oils are introduced as a masking agent into biodegradable resin formulations, the odor is improved but the physical properties may deteriorate; however, in the present invention, the physical properties of the biodegradable resin composition and biodegradable film could be improved by simultaneously introducing the essential oil as a masking agent and a compatibilizer. In addition, the essential oil acts as an auxiliary lubricant, reducing friction between the mold and the starch-based composite material, thereby preventing the deterioration of thermoplastic starch (TPS) and improving physical properties. Furthermore, as a masking agent, it is possible to secure functions such as fragrance imparting, antibacterial, and insecticidal effects.

[0025] Specifically, according to the present invention, simultaneously introducing a carbodiimide-based compatibilizer and an essential oil such as eucalyptol into a starch-based biodegradable resin composition has the effect of significantly improving the color, odor, and mechanical strength of a starch-containing film. Therefore, it can be seen that the biodegradable resin composition according to the present invention is suitable for application to soft films such as mulching films.

[0026] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0027] A biodegradable resin composition according to an embodiment of the present invention comprises, based on 100 parts by weight of the biodegradable resin composition, 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil.

[0028] The present invention will be described in more detail below with reference to the examples. However, the following examples are provided as examples to aid in understanding the invention and do not limit the scope of the invention. The present invention may be modified in various ways and may be implemented in various different forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0029] Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0030] The biodegradable resin composition according to the present invention comprises, based on 100 parts by weight of the biodegradable resin composition, 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil.

[0031] Resin compositions containing starch and biodegradable resins suffer from reduced moisture resistance due to the hydrophilicity of starch, and a decrease in flowability caused by the inclusion of starch, which generally has a larger molecular weight than the biodegradable resin. Additionally, because the compatibility between starch and the biodegradable resin is poor, there is a problem of reduced mechanical strength in the manufactured film, requiring improvement of physical properties. Furthermore, the carbonization of starch has an adverse effect on the color and odor of films and other products manufactured using it. For example, during the compounding or film processing of compositions containing thermoplastic starch, browning occurs during high-temperature and high-pressure processes, and a caramel scent or burnt odor may be emitted, leading to a deterioration in quality.

[0032] To solve these problems, the present invention is characterized by introducing a compatibilizer and an essential oil masking agent into a starch-based biodegradable resin composition.

[0033] As a result of comparing the physical properties of various types of compatibilizers introduced into biodegradable resin compositions, it was confirmed that using carbodiimide-based compatibilizers is preferable.

[0034] Carbodiimide-based compatibilizers react with the hydroxyl groups of starch to increase interfacial adhesion and stiffness, thereby enhancing the mechanical properties of starch-based composite materials.

[0035] Furthermore, the use of carbodiimide-based compatibilizers reduces the water absorption rate of starch-based biodegradable resin compositions and films due to the reduction of hydroxyl groups. Additionally, carbodiimide-based compatibilizers can restore physical properties by inhibiting the activity of carboxyl groups and reducing acid content, thereby preventing the degradation of polyester chains through crosslinking; moreover, the ester bonds have the effect of improving hydrolytic resistance and adhesion to biodegradable resins.

[0036] Available compatibilizers may be carbodiimide-based compatibilizers, and may be one or more selected from, for example, polymeric carbodiimide, monomeric carbodiimide, linear aromatic carbodiimide, sterically hindered aromatic carbodiimide, aliphatic carbodiimide, cycloaliphatic carbodiimide, functionalized carbodiimide, and heteroaromatic carbodiimide, but are not limited thereto.

[0037] Additionally, the polymeric carbodiimide may specifically be one or more selected from aliphatic polymeric carbodiimide, aromatic polymeric carbodiimide, and hybrid polymeric carbodiimide, but is not limited thereto.

[0038] Meanwhile, when essential oils are used as a masking agent together with a commercializing agent, they act as an auxiliary lubricant, which reduces friction between the mold and the starch-based composite material, thereby preventing the deterioration of thermoplastic starch (TPS) and improving physical properties, and it is also possible to secure functions such as fragrance imparting, antibacterial, and insecticidal effects.

[0039] Available essential oils may be one or more selected from, for example, eucalyptol, vanillin, lavender, lemongrass, and orange oil, but are not limited thereto.

[0040] The present invention is characterized by introducing a carbodiimide-based compatibilizer and an essential oil masking agent into a starch-based biodegradable resin composition, and accordingly, has the effect of significantly improving the odor, water immersion leaching characteristics, and mechanical strength of a starch-containing film.

[0041] The thermoplastic starch used in the biodegradable resin composition according to the embodiment of the present invention is starch prepared by reacting starch with a plasticizer, and may further include a compatibilizer or an additive.

[0042] Starches that can be used 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 are not limited thereto. When less than 70% by weight of starch is used among the thermoplastic starch, an excessive amount of raw materials other than starch may be used, and the cost may increase, making it uneconomical; when more than 90% by weight is used, some unplasticized starch may remain, which may cause a deterioration in physical properties when manufacturing the thermoplastic starch and biodegradable composite resin.

[0043] Plasticizers usable with thermoplastic starch may be, for example, one or more selected from the group consisting of glycerin, ethylene glycol, sorbitol, or pentaerythritol, but are not limited thereto. It is preferable to use the plasticizer in a range of 1 to 30 weight percent based on the total weight of the thermoplastic starch. If the content of the plasticizer is less than the above range, the plasticization reaction does not occur, and if it exceeds the range, there is a problem of excessive plasticization resulting in a paste-like consistency.

[0044] Thermoplastic starch may further include a compatibilizer in addition to starch and a plasticizer. For example, one or more may be selected from the group consisting of maleic anhydride, fumaric anhydride, acetylenedicarboxylic anhydride, glutaconic anhydride, 2-decenedioic anhydride, traumamatinic anhydride, muconic anhydride, glutinous anhydride, citraconic anhydride, mesaconic anhydride, itaconic anhydride, maleic acid, fumaric acid, acetylenedicarboxylic anhydride, glutaconic acid, 2-decenedioic anhydride, traumamatinic acid, muconic acid, glutinous acid, citraconic acid, mesaconic acid, and itaconic acid, but are not particularly limited thereto. Based on the total weight of the thermoplastic starch, it is preferable to use the compatibilizer in a range of 0.1 to 2 weight percent.

[0045] After preparing thermoplastic starch by manufacturing or purchasing it, a biodegradable resin, a activator, an essential oil, a lubricant, and an inorganic filler are mixed, and a starch-based biodegradable resin composition is prepared by high-temperature reaction in an extruder.

[0046] In addition, the biodegradable resin usable in the biodegradable resin composition according to the example may be selected from one or more of polybutylene adipate terephthalate, polylactic acid, polycaprolactone, polybutylene succinate, polyglycolic acid, polyhydroxyalkanoate, polyhydroxybutylate, copolymers thereof, and mixtures thereof, but is not limited thereto.

[0047] In addition, the inorganic filler usable in the biodegradable resin composition according to the example may be one or more selected from natural fiber powders such as calcium carbonate, talc, kaolin, barium sulfate, wollastonite, glass fiber, and cellulose microfiber, but is not limited thereto. It is preferable to use the inorganic filler in a range of 5 to 25 parts by weight per 100 parts by weight of the starch-based biodegradable resin composition. The inorganic filler is incorporated into the biodegradable compound to complement mechanical properties such as tensile strength and tear strength of the film, and has the advantage of allowing for the configuration of properties and costs through various formulation ratios ranging from low to high content to reduce costs. If the inorganic filler is used below the above range, the cost of the biodegradable compound is high, resulting in reduced price competitiveness; if used above the range, dispersion efficiency decreases, and the elongation rate of the film is significantly reduced, causing problems such as loss of flexibility of the film.

[0048] In addition, the lubricant usable in the biodegradable resin composition according to the example may be one or more selected from calcium stearate, glycerin monostearate, zinc stearate, magnesium stearate, ethylene bisstearamide, fatty acid esters, and waxes, but is not limited thereto. It is preferable to use the lubricant in a range of 0.1 to 2 parts by weight per 100 parts by weight of the starch-based biodegradable resin composition. The lubricant is used to serve as a lubricant that reduces the load due to the dispersion effect between the thermoplastic starch, the biodegradable resin, and the inorganic filler, as well as the release effect on the metal surface during the extrusion process. If the lubricant is used below the above range, the dispersion efficiency between the resins decreases and extrusion processability is significantly reduced, and if used above the range, it may cause a deterioration in film properties.

[0049] A method for manufacturing a biodegradable film according to the present invention comprises the steps of: feeding 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil into an extruder to produce pellets; and manufacturing the pellets into a film using a film forming machine.

[0050] In the method for manufacturing the above biodegradable film, the compatibilizer is polymeric carbodiimide, and the essential oil may be one or more selected from eucalyptol, vanillin, lavender, lemongrass, and orange oil.

[0051] The biodegradable resin product according to the present invention can be manufactured using a twin-screw extruder, etc., and the reaction temperature of the extruder may be in the range of 150 to 180 ℃, but is not limited thereto. For example, the barrel temperature of the extruder may be in the range of 160 to 170 ℃, the main screw speed may be about 180 rpm, and the raw material feeding speed may be about 15 rpm for the main feeder and about 4 rpm for the side feeder.

[0052] The method may further include a step of cooling and drying the starch-based biodegradable resin composition extruded after a high-temperature reaction in an extruder to form pellets. The extruded material discharged through the extruder die is water-cooled and pelletized by installing a water channel. The biodegradable resin composition in pellet form is desirable as it can provide convenience in product formulation and processing.

[0053] In addition, the above pellets can be dried at 60°C for 24 hours or more to produce a biodegradable resin composition for film, and a biodegradable film can be produced by feeding this into a film forming machine. The temperature of the film forming machine may be in the range of 160 to 230°C, but is not limited thereto. For example, the temperature of the film forming machine may be in the range of 170 to 180°C or 210 to 220°C, the raw material feeding speed may be about 25 to 30 rpm, and the film roller speed may be adjusted to 6 to 8 rpm to produce the film, but is not limited thereto, and it is possible to change the manufacturing process depending on the product to which it is applied.

[0054] The tensile strength of the biodegradable resin composition using PBAT as the biodegradable resin in the present invention is 16.5 to 30.0 N / mm 2 The range is 342 to 824%, and the tear strength may be in the range of 93 to 143 N / mm.

[0055] In addition, the water immersion leaching characteristic of the biodegradable resin composition using the above PBAT is in the range of 9.0 to 9.8%, the color L value of the film measured using a colorimeter (Konica Minolta) is in the range of 70 to 75, and the color b value may be in the range of 22 to 23.

[0056] In the present invention, the tensile strength of the biodegradable resin composition using PLA as the biodegradable resin may be in the range of 46.1 to 51.1 MPa, the flexural strength may be in the range of 87.8 to 95.7 MPa, and the flexural modulus may be in the range of 3516 to 3976 MPa. In addition, the notched IZOD impact strength of the resin composition may be 2.5 to 4.4 KJ / m² 2 It could be.

[0057] In addition, the color of the biodegradable resin composition using the above PLA may be such that the color L value of the film, measured using a colorimeter (Konica Minolta), is in the range of 72.6 to 75.9, the color a value is in the range of 1.7 to 2.0, and the color b value is in the range of 17.1 to 18.2.

[0058] The present invention is characterized by the introduction of a carbodiimide-based compatibilizer and an essential oil masking agent into a starch-based biodegradable resin composition, and it has been confirmed that this has the effect of significantly improving the odor, water immersion leaching characteristics, and mechanical strength of a starch-containing film.

[0059] The biodegradable film manufactured according to the example has excellent color, odor, and mechanical strength, so it can be used in various products such as disposable bags, disposable packaging materials, tablecloths, and mulching films.

[0060] The present invention is described in more detail below through examples and comparative examples, but these are illustrative and should not be interpreted as limiting the scope of the invention.

[0061] Evaluation by type of masking agent

[0062] <Comparative Example 1>

[0063] 25 parts by weight of thermoplastic starch, 55 parts by weight of biodegradable resin (PBAT), 20 parts by weight of inorganic filler (CaCO3), and 0.2 parts by weight of lubricant (Ca-stearate) are mixed.

[0064] The uniformly mixed composition is fed into a twin-screw extruder. The extruder barrel temperature is 160–170°C, the main screw speed is 180 rpm, and the raw material feeding speed is 15 rpm for the main feeder and 6 rpm for the side feeder. The extruded material discharged through the extruder die is water-cooled and pelletized by installing a water channel.

[0065] A biodegradable resin composition for film is prepared by drying pellets at 60°C for at least 24 hours.

[0066] The above biodegradable resin composition is fed into a film forming machine to produce a biodegradable film. The temperature of the film forming machine is 170 to 180°C, and the raw material feeding speed is 25 to 30 rpm. The film is produced by adjusting the film roller speed to 6 to 8 rpm.

[0067] <Comparative Example 2>

[0068] Except for adding 0.1 parts by weight of Vanillin as a masking agent, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0069] <Comparative Example 3>

[0070] Except for adding 0.1 parts by weight of Orange Oil as a masking agent, the method for manufacturing the biodegradable resin composition and the method for manufacturing the biodegradable film are the same as in Comparative Example 1.

[0071] <Comparative Example 4>

[0072] Except for adding 0.1 parts by weight of Eucalyptol as a masking agent, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0073] <Comparative Example 5>

[0074] Except for adding 0.1 parts by weight of Lavender as a masking agent, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0075] <Comparative Example 6>

[0076] Except for adding 0.1 parts by weight of Lemongrass as a masking agent, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0077] <Evaluation Example 1>

[0078] A. Material property evaluation methods

[0079] The physical properties of the biodegradable resin composition and film prepared in the comparative example were evaluated according to the following method.

[0080] 1) Melt Flow Index Evaluation

[0081] The Melt Flow Index of the biodegradable composite material prepared by the manufacturing method in the examples and comparative examples is measured using an MFI measuring instrument. The weight of the molten material passing through by heat for 10 minutes under conditions of 190°C and a 2.16 kg load is measured.

[0082] 2) Evaluation of the mechanical strength of the film

[0083] After cutting the biodegradable films prepared according to the examples and comparative examples to prepare specimens according to specifications, the tensile strength, elongation, and tear strength are measured using an Instron tensile testing machine.

[0084] 3) Evaluation of Water Immersion and Elution Characteristics

[0085] Biodegradable films prepared according to the examples and comparative examples are cut into 5x10 cm pieces to prepare specimens, and after drying in a 50°C hot air dryer, the initial weight is measured. Immersion in water is performed (water immersion elution conditions: room temperature, 500 mL of water, 24 hours), and the specimens are removed, dried in a 50°C hot air dryer, and then weighed. The water immersion elution rate is evaluated by calculating the weight loss rate.

[0086] 4) Film Color Evaluation

[0087] The biodegradable film prepared according to the above examples and comparative examples is cut and overlapped to a thickness of 0.5 mm to prepare specimens. The color of each specimen is measured using a colorimeter (Konica Minolta).

[0088] 5) Film odor evaluation

[0089] A biodegradable film prepared according to the above examples and comparative examples is cut to prepare specimens. A panel of 10 men and women is formed for the experimental group to conduct a sensory evaluation and assess the intensity and preference of the odor.

[0090] Smell intensity is rated on a 5-point scale, with lower scores given for more severe unpleasant odors such as burnt smells and higher scores for odorless smells.

[0091] B. Results of physical property evaluation

[0092] The results of measuring the physical properties of the film using the above method are shown in [Table 1] and [Table 2] below. From these results, it can be seen that Comparative Example 4, which used Eucalyptol essential oil as a masking agent, has the effect of reducing water immersion leaching and increasing mechanical strength. In the tables below, the unit of the formulation ratio (content) is parts by weight.

[0093] Classification Comparative Example 1 Comparative Example 2 Comparative Example 3 Mixing Ratio Masking agent type - Vanillin Orange Oil content - 0.1 0.1 Physical property analysis results MFI (g / 10min) 2.2 1.6 1.6 Tensile strength (N / mm 2 )26.5 23.0 21.6 Elongation (%) 78 16 00 679 Tear Strength (N / mm) 10 210 8101 Water Immersion Leaching (%) 11.0 16.0 14.4 Odor (5-point scale) 1.0 3.5 2.0 Color L*(Lightness) 79.3 80.6 76.0 b*(Yellow-Blue) 19.8 18.4 20.2

[0094] Classification Comparative Example 4 Comparative Example 5 Comparative Example 6 Mixing Ratio Masking Agent Type Eucalyptol Lavender Lemongrass Content 0.1 0.1 0.1 Physical Property Analysis Results MFI (g / 10min) 2.5 1.9 1.8 Tensile Strength (N / mm 2 )30.0 29.5 27.8 Elongation (%) 824 80 9778 Tear Strength (N / mm) 96 9393 Water Immersion Leaching (%) 9.7 12.3 12.3 Odor (5-point scale) 3.5 3.0 3.5 Color L*(Lightness) 80.2 78.4 79.7 b*(Yellow-Blue) 18.6 19.6 19.5

[0095] Evaluation by type of commercial agent

[0096] <Example 1>

[0097] Except for adding 0.2 parts by weight of Polymeric Carbodiimide as a compatibilizer, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0098] <Example 2>

[0099] Except for adding 0.2 parts by weight of Epoxy Glycidyl methacrylate as a compatibilizer, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0100] <Example 3>

[0101] Except for adding 0.2 parts by weight of Epoxy Poly(Butadiene) as a compatibilizer, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0102] <Example 4>

[0103] Except for adding 0.2 parts by weight of 3-Glycidoxypropyltrimethoxysilane as a compatibilizer, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0104] <Example 5>

[0105] Except for adding 0.2 parts by weight of maleic anhydride as a compatibilizer, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 1.

[0106] <Evaluation Example 2>

[0107] The results of the physical property evaluation of the biodegradable resin composition and film of the example, measured by the physical property evaluation method of Evaluation Example 1, are shown in [Table 3] and [Table 4] below. From these results, it can be seen that the biodegradable resin composition and film of Example 1, using a Polymeric Carbodiimide compatibilizer, exhibit the effect of reduced water immersion leaching and increased mechanical strength. In the tables below, the unit of the mixing ratio (content) is parts by weight.

[0108] Classification Comparison Example 1 Example 1 Example 2 Formulation Type of incompatible agent - Polymeric Carbodiimide Epoxy Glycidyl methacrylate Content - 0.2 0.2 Physical Property Analysis Results MFI (g / 10min) 2.2 1.4 2.1 Tensile Strength (N / mm2 )26.5 29.4 27.5 Elongation (%) 78 16 49 673 Tear Strength (N / mm) 10 21 42 135 Water Immersion Leaching (%) 11.0 9.8 11.2 Odor (5-point scale) 1.0 1.0 1.0 Color L*(Lightness) 79.3 71 373.6 b*(Yellow-Blue) 19.8 22.9 22.6

[0109] Classification Example 3 Example 4 Example 5 Formulation Type of Incompatible Compounding Agent Epoxy Poly(Butadiene) 3-Glycidoxypropyl trimethoxysilane Maleic anhydride Content 0.2 0.2 0.2 Physical Property Analysis Results MFI (g / 10min) 1.1 0.8 2.9 Tensile Strength (N / mm 2 )27.5 21.9 16.5 Elongation (%) 59 73 89 34 2 Tear Strength (N / mm) 11 4 12 6 11 4 Water Immersion Leaching (%) 11 1 2.6 13.1 Odor (5-point scale) 1.0 1.0 1.0 Color L*(Lightness) 74.4 75.8 79.8 b*(Yellow-Blue) 20.2 20.6 18.5

[0110] Evaluation of Commercialization and Masking Agent Application

[0111] <Example 6>

[0112] Except for adding 0.2 parts by weight of a compatibilizer and 0.1 parts by weight of a masking agent, the method for manufacturing a biodegradable resin composition and the method for manufacturing a biodegradable film are the same as in Comparative Example 1.

[0113] <Comparative Example 7>

[0114] A biodegradable resin composition and a biodegradable film were prepared as follows by using PLA instead of PBAT as the biodegradable resin.

[0115] 20 parts by weight of thermoplastic starch and 80 parts by weight of PLA are mixed. The uniformly mixed composition is fed into a twin-screw extruder. The extruder barrel temperature is 170–190°C, the main screw speed is 180 rpm, and the raw material feeding speed is 15 rpm. The extruded material discharged through the extruder die is water-cooled and pelletized by installing a water channel. The pellets are dried at 60°C for at least 24 hours to produce a biodegradable composition for film.

[0116] The above biodegradable composition is fed into an injection molding machine to produce a biodegradable composite injection specimen. The temperature of the injection molding machine is 210 to 220°C.

[0117] <Example 7>

[0118] Except for adding 1 part by weight of Polymeric Carbodiimide, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 7.

[0119] <Example 8>

[0120] Except for adding 0.1 parts by weight of eucalyptol, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 7.

[0121] <Example 9>

[0122] Except for adding 0.1 parts by weight of vanillin, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 7.

[0123] <Example 10>

[0124] Except for adding 1 part by weight of Polymeric Carbodiimide and 0.1 part by weight of Eucalyptol, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 7.

[0125] <Example 11>

[0126] Except for adding 1 part by weight of Polymeric Carbodiimide and 0.1 part by weight of Vanillin, the method for preparing the biodegradable resin composition and the method for preparing the biodegradable film are the same as in Comparative Example 7.

[0127] <Evaluation Example 3>

[0128] A. Material property evaluation methods

[0129] 1) Melt flow index

[0130] The Melt Flow Index of the biodegradable composite material prepared by the manufacturing method of the Examples and Comparative Examples is measured using an MFI measuring instrument. The weight of the molten material passing through by heat for 10 minutes under conditions of 190°C and a 2.16 kg load is measured.

[0131] 2) Tensile strength and elongation

[0132] Biodegradable composite specimens are prepared according to the manufacturing methods of the examples and comparative examples. Tensile strength and elongation of each specimen are measured using the UTM tensile test method.

[0133] 3) Impact strength

[0134] Biodegradable composite specimens are prepared according to the manufacturing methods of the examples and comparative examples. The impact strength of each specimen is measured using the Notched IZOD impact test method.

[0135] 4) Color

[0136] The color of the film of the biodegradable injection molded specimen prepared by the manufacturing method of the example and comparative example is measured using a colorimeter (Konica Minolta).

[0137] 5) Smell

[0138] Biodegradable injection-molded specimens are prepared by the manufacturing methods of the examples and comparative examples. A panel of 10 men and women is formed for the experimental group to conduct a sensory evaluation and assess the odor intensity. Odor intensity is evaluated using a 5-point scale, where lower scores are assigned for more severe unpleasant odors, such as burnt smells, and higher scores for odorless smells.

[0139] B. Results of physical property evaluation

[0140] The results of measuring the physical properties of the film using the above physical property evaluation method are shown in [Table 5] to [Table 7] below. In the tables below, the unit of the mixing ratio (content) is parts by weight.

[0141] Classification Comparative Example 1 Comparative Example 4 Example 1 Example 6 Formulation Non-compatibility Agent Polymeric Carbodiimide--0.2 0.2 Masking agent Eucalyptol-0.1 -0.1 Physical Property Analysis Results MFI (g / 10min) 2.2 2.5 1.4 2.0 Tensile Strength (N / mm² 2 )26.5 30 29.4 28.8 Elongation (%) 78 18 24 6 49 680 Tear Strength (N / mm) 10 29 6 14 21 43 Water Immersion Leaching (%) 11.0 9.7 9.8 9.0 Odor (5-point scale) 1.0 3.5 1.0 3.0 Color L*(Lightness) 79.3 80.2 71.3 74.8 b*(Yellow-Blue) 19.8 18.6 22.9 22.2

[0142] Classification Comparison Example 7 Example 7 Example 8 Formulation Non-compatibility Agent Polymeric Carbodiimide-1.0-Masking agent Type--Eucalyptol Content--0.1 Physical Property Analysis Results MFI (g / 10min) 4.4 4.0 4.9 Tensile Strength (MPa) 46.5 48.5 47.5 Elongation (%) 7.2 6.5 5.6 Flexural Strength (MPa) 88.6 91.2 95.7 Flexural Modulus (MPa) 299 635 46 3937 Notch Impact Strength (KJ / m 2 )4.54.44.4 Smell (5-point system)3.02.54.0 Chromaticity L*(Lightness)72.172.675.7a*(Red-Green)2.121.7b*(Yellow-Blue)18.718.217.7

[0143] Classification Example 9 Example 10 Example 11 Composition Incompatibility Agent Polymeric Carbodiimide-1.0 1.0 Masking Agent Type Vanillin Eucalyptol Vanillin Content 0.1 0.1 0.1 Physical Property Analysis Results MFI (g / 10min) 4.7 4.2 4.7 Tensile Strength (MPa) 46.9 51.1 46.1 Elongation (%) 4.8 5.1 3.2 Flexural Strength (MPa) 87.1 94.7 87.8 Flexural Modulus (MPa) 36 95 39 76 35 16 Notch Impact Strength (KJ / m² 2 )3.4 4.3 2.5 Smell (5-point system) 2.0 4.0 2.0 Chromaticity L*(Lightness) 75.9 74.8 73.5 a*(Red-Green) 1.7 1.7 1.7 b*(Yellow-Blue) 17.1 17.8 17.4

[0144] From the above evaluation results, it can be seen that the biodegradable film of Example 6, using a Polymeric Carbodiimide compatibilizer and Eucalyptol essential oil, exhibits the effect of reduced water leaching and increased mechanical strength. Additionally, it can be seen that the biodegradable film of Example 10, using a Polymeric Carbodiimide compatibilizer and Eucalyptol essential oil, exhibits the effect of increased mechanical strength and reduced starch odor.

[0145] When essential oils are introduced as a masking agent into biodegradable resin formulations, the odor is improved but the physical properties may deteriorate; however, in the present invention, the physical properties of the biodegradable resin composition and biodegradable film could be improved by simultaneously introducing the essential oil as a masking agent and a compatibilizer. As such, it can be confirmed that the biodegradable resin composition and film prepared using a compatibilizer and an essential oil as a masking agent according to the present invention have superior odor, water immersion leaching characteristics, and mechanical strength compared to the comparative example.

[0146] From the foregoing description, those skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. In this regard, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention should be interpreted as including all modifications or variations derived from the meaning and scope of the claims set forth below and their equivalents, rather than from the detailed description above.

Claims

1. A biodegradable resin composition comprising, based on 100 parts by weight of the biodegradable resin composition, 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil.

2. In Paragraph 1, The above compatibilizer is a biodegradable resin composition that is a carbodiimide-based compatibilizer.

3. In Paragraph 1, The above essential oil is a biodegradable resin composition selected from one or more of eucalyptol, vanillin, lavender, lemongrass, and orange oil.

4. In Paragraph 1, The above biodegradable resin composition is one or more selected from polybutylene adipate terephthalate, polylactic acid, polycaprolactone, polybutylene succinate, polyglycolic acid, polyhydroxyalkanoate, polyhydroxybutylate, and copolymers thereof.

5. In Paragraph 1, The above-mentioned inorganic filler is a biodegradable resin composition selected from one or more of calcium carbonate, talc, kaolin, barium sulfate, wollastonite, glass fiber, and cellulose microfiber.

6. In Paragraph 1, A biodegradable resin composition in which the above lubricant is one or more selected from calcium stearate, glycerin monostearate, zinc stearate, magnesium stearate, ethylene bisstearamide, fatty acid esters, waxes, and derivatives thereof.

7. A step of producing pellets by feeding 10 to 30 parts by weight of thermoplastic starch, 50 to 70 parts by weight of biodegradable resin, 5 to 25 parts by weight of inorganic filler, 0.1 to 2 parts by weight of lubricant, 0.05 to 1 part by weight of compatibilizer, and 0.02 to 0.5 parts by weight of essential oil into an extruder; and A method for manufacturing a biodegradable film comprising the step of feeding the above pellets into a film forming machine to manufacture a film.

8. In Paragraph 7, A method for manufacturing a biodegradable film in which the above-mentioned compatibilizer is polymeric carbodiimide, and the above-mentioned essential oil is one or more selected from eucalyptol, vanillin, lavender, lemongrass, and orange oil.

9. A biodegradable film manufactured using the biodegradable resin composition according to claim 1.

10. In Paragraph 9, A biodegradable film having a tensile strength of 20 to 55 MPa or higher and a water immersion dissolution rate of the compound measured after immersion in water at room temperature for 24 hours of 10% or lower.