Resin composition and biodegradable resin product comprising the same

Abstract

The invention relates to a resin composition and a biodegradable resin product comprising the same. The resin composition comprises poly (butylene adipate-co-butylene terephthalate), meso-polylactic acid, and a maleic anhydride grafted polyolefin elastomer, and the weight ratio of the poly (butylene adipate-co-butylene terephthalate) to the meso-polylactic acid is from 9.0: 1.0 to 6.0: 4.0. Therefore, the resin composition has excellent mechanical properties and high biodegradability.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10 - 2023 - 0129095, filed with the Korean Intellectual Property Office on September 26, 2023, and Korean Patent Application No. 10 - 2024 - 0130452, filed with the Korean Intellectual Property Office on September 26, 2024, the disclosures of which are incorporated herein by reference in their entireties. Technical field

[0003] The present invention relates to a resin composition and a biodegradable resin product containing the same. Background art

[0004] Thermoplastic polymer resins are used in various fields due to their excellent mechanical and chemical properties, including drinking water containers, medical uses, food wrapping paper, food containers, automotive moldings, agricultural vinyl films, etc.

[0005] Since thermoplastic polymer resins, especially polyethylene films, etc., have excellent mechanical properties, are harmless to the human body, and can be continuously deformed by heat, they are widely used as heat - seal bags for food packaging or agricultural ground covers, etc.

[0006] Heat - seal bags for food packaging are mainly used for vacuum packaging of food, etc., and a large amount of polyethylene films, etc., which can achieve excellent adhesive strength even at low sealing temperatures, are used.

[0007] Agricultural films are mainly used for covering agriculture. A cover is a material that covers the soil surface when cultivating crops. If the upper surface of the soil is covered with various materials, the growth and development of weeds can be prevented, and damage by harmful insects can be prevented, so the use of pesticides can be reduced. In addition, the soil temperature can be easily controlled, beneficial bacteria in the soil can proliferate, soil erosion can be prevented, and soil moisture can be maintained.

[0008] As such a covering material, for example, leaves of crops such as straw, trees, and plants, or polyolefin films, etc., can be mentioned, and synthetic resins such as polyethylene films are generally used in large quantities.

[0009] However, the polyethylene film of the heat - seal bag widely used as a food packaging or covering material does not degrade in the natural environment and has limitations in recycling. In particular, it is recently known that plastics, such as discarded polyethylene films, flow into the sea and are broken into tiny microplastics in the sea through backflow and sunlight.

[0010] Currently, it is known that such microplastics float in the sea in an immeasurable quantity of billions to hundreds of billions, and they enter marine organisms and accumulate in the ecosystem to affect the entire food chain.

[0011] Therefore, it is necessary to study alternatives to previously used thermoplastics.

[0012] To solve such problems, recently, active attempts have been made to develop covering films composed of photodegradable or biodegradable polymers. However, the biodegradability is insufficient, and the mechanical properties are inferior to those of existing polyethylene films. Summary of the Invention

[0013] Technical Problem

[0014] An object of the present invention is to provide a resin composition having excellent mechanical properties and exhibiting high biodegradability.

[0015] Another object of the present invention is to provide a biodegradable resin product containing the above resin composition.

[0016] Technical Solution

[0017] According to the present disclosure, there is provided a resin composition comprising:

[0018] Poly(butylene adipate-co-butylene terephthalate),

[0019] meso-Polylactic acid, and

[0020] maleic anhydride-grafted polyolefin elastomer,

[0021] wherein the composition comprises poly(butylene adipate-co-butylene terephthalate) and meso-polylactic acid in a weight ratio of 9.0:1.0 to 6.0:4.0.

[0022] According to the present invention, there is also provided a biodegradable resin product containing the resin composition.

[0023] The terms used herein are only for explaining specific embodiments and are not intended to limit the present invention.

[0024] Unless the context clearly indicates otherwise, singular expressions include their plural expressions.

[0025] As used herein, the term "comprising" is intended to mean the presence of features, quantities, steps, structural elements, or combinations thereof for practice, and is not intended to exclude the possibility of the presence or addition of one or more other features, quantities, steps, structural elements, or combinations thereof.

[0026] Unless otherwise defined herein, room temperature is 25 ± 5°C and atmospheric pressure is 760 ± 20 Torr.

[0027] Although various modifications can be made to the present disclosure and the present invention can have various forms, specific examples will be described and explained in detail below. However, it should be understood that these are not intended to limit the present invention to the specific disclosure, and the present invention includes all its modifications, equivalents or alternative forms without departing from the spirit and technical scope of the present invention.

[0028] Hereinafter, the present disclosure will be explained in detail.

[0029] The inventors of the present disclosure found that when preparing a resin composition using poly(butylene adipate-co-terephthalate) (PBAT) and meso-polylactic acid (Meso PLA), high biodegradability and excellent mechanical properties such as tensile strength, elongation at break, tensile modulus, etc. can be achieved when meso-polylactic acid and poly(butylene adipate-co-terephthalate) are mixed in an optimal weight ratio and a maleic anhydride-grafted polyolefin elastomer is used together, and thus the present invention was completed.

[0030] PBAT is a biodegradable polymer that exhibits high elongation at break and ductility. However, due to its low mechanical properties including tensile strength, tensile modulus, etc., its applications are limited. To overcome this limitation, by using PBAT in combination with other biodegradable polymers, the application range can be expanded and the performance can be improved.

[0031] Meanwhile, poly(lactic acid) (PLA) or polylactide is a biodegradable polymer with high tensile strength and tensile modulus. However, PLA exhibits biodegradability only under specific biodegradation conditions, especially industrial composting conditions, and its biodegradability is limited under other conditions. This property of PLA may affect the biodegradability of the PBAT / PLA blend.

[0032] Therefore, the resin composition according to one aspect of the present disclosure contains Meso PLA in an optimal weight ratio relative to PBAT instead of conventional PLA, thereby exhibiting significantly improved biodegradability and excellent mechanical properties.

[0033] Specifically, the resin composition according to one aspect of the present disclosure contains poly(butylene adipate-co-terephthalate) (PBAT) and meso-polylactic acid (Meso PLA) in a weight ratio of 9.0:1.0 to 6.0:4.0.

[0034] More specifically, PBAT:Meso PLA in the resin composition can be 9.0:1.0 or less, or 8.7:1.3 or less, and 6.0:4.0 or more, or 7.0:3.0 or more, or 8.0:2.0 or more. Herein, the expressions "or more" and "or less" are based on the content of PBAT.

[0035] If PBAT: Meso PLA is greater than 9.0:1.0 and the content of Meso PLA is too low compared to PBAT, the resin composition may not exhibit sufficient biodegradability. In addition, if PBAT: Meso PLA is less than 6.0:4.0 and the content of Meso PLA is too high compared to PBAT, the rigidity may increase, and thus, the elongation at break of the resin composition may decrease. In particular, in the case of processing the resin composition into a biodegradable film or the like, the processability may decrease, and the required properties for covering films or the like may not be achieved. Herein, the expressions "greater than" and "less than" are based on the content of PBAT.

[0036] In addition, while satisfying the weight ratio range of PBAT and Meso PLA, the content of Meso PLA may be 7.0 parts by weight to 75.0 parts by weight based on 100 parts by weight of PBAT. More specifically, based on 100 parts by weight of PBAT, it may be included in an amount of 7.0 parts by weight or more, or 10.0 parts by weight or more, or 14.0 parts by weight or more, or 14.5 parts by weight or more and 75.0 parts by weight or less, or 70.0 parts by weight or less, or 68.0 parts by weight or less.

[0037] "Polylactic acid" herein means a polymer of lactide and has the same meaning as "polylactide" and "PLA".

[0038] The lactide or lactide monomer may be L-lactide derived from 2 L-lactic acid molecules; D-lactide derived from 2 D-lactic acid molecules; meso-lactide derived from an L-lactic acid molecule and a D-lactic acid molecule; or a mixture of two or more of them. In addition, it may be racemic lactide, which is a 50:50 mixture of L-lactide and D-lactide. Thus, the PLA herein may be a lactide polymer selected from L-lactide, D-lactide, meso-lactide, racemic lactide, and mixtures of two or more of them.

[0039] PLA having various structures can be synthesized from lactide by ring-opening polymerization according to spatial control.

[0040] Poly(L-lactic acid) (a polymer of L-lactide) and poly(D-lactic acid) (a polymer of D-lactide) are structurally identical. It has the highest crystallinity among PLA and exhibits semi-crystalline properties. As the proportion of D-lactide in the PLA structure increases, it shows amorphous properties, but if the content of D-lactide in the PLA structure exceeds 10%, the processability will decrease. Therefore, PLA usually has a high ratio of L-lactide, and commercial products usually have an L-lactide content of more than 95% and a D-lactide content of less than 5%.

[0041] At the same time, the solid-state morphology, degree of crystallinity, and primary chemical structure of PLA have an impact on the degradation characteristics of PLA.

[0042] The solid-state morphology refers to the shape, thickness, surface area, etc. of PLA, among which the shape is very important for inducing effective degradation.

[0043] The crystallinity of PLA is also an important factor affecting the degradation characteristics of PLA.

[0044] Generally, if water (H2O) diffuses into PLA, PLA begins to degrade in the amorphous region, and then random hydrolysis occurs. As a result, PLA degrades from the polymer in the form of oligomers, then fragments, and is converted into CO2 and H2O through more extensive hydrolysis by diffusion and metabolism. Therefore, amorphous PLA can exhibit more excellent degradation characteristics than crystalline PLA.

[0045] The primary chemical structure of PLA, especially the presence of functional groups, and the hydrophilic-hydrophobic balance also have an impact on the degradation characteristics of PLA.

[0046] In the present disclosure, Meso PLA is a polymer prepared by the polymerization of meso-lactide. Specifically, it can be a random polymer containing repeating units represented by the following Chemical Formula 1:

[0047] [Chemical Formula 1]

[0048]

[0049] In Chemical Formula 1, n is an integer of 2 or more.

[0050] In addition, Meso PLA can meet the following requirements (a1) and (a2).

[0051] (a1) Density (ISO1183): 1.15 g / ml to 1.35 g / ml

[0052] (a2) Melt flow index (MFI) (ISO1133-11, 190 °C, 2.16 kg): 3 g / 10 min to 15 g / 10 min

[0053] More specifically, the density (ISO1183) of Meso PLA may be 1.15 g / ml or more, or 1.20 g / ml or more, or 1.22 g / ml or more, or 1.24 g / ml or more and 1.35 g / ml or less, or 1.30 g / ml or less, or 1.25 g / ml or less.

[0054] In addition, the melt flow index (MFI) (ISO1133-11, 190 °C, 2.16 kg) of Meso PLA may be 3 g / 10 min, or 5 g / 10 min or more, or 7 g / 10 min or more, and 15 g / 10 min or less, or 10 g / 10 min or less, or 9 g / 10 min or less.

[0055] When the above Meso PLA satisfies the above density and melt flow index conditions, mechanical properties such as tensile strength and tensile modulus are more excellent, which is more advantageous in improving the biodegradability of the resin composition.

[0056] In the resin composition of the present invention, the above meso-polylactic acid may be composed only of the repeating units represented by the above chemical formula 1. That is, it may be a meso-lactide homopolymer that does not contain repeating units other than the repeating units represented by chemical formula 1.

[0057] In addition, in the resin composition according to the present disclosure, poly(butylene adipate-co-butylene terephthalate) (PBAT) may satisfy the following requirements (b1) and (b2).

[0058] (b1) Melting temperature (Tm): 100 °C to 140 °C

[0059] (b2) Melt index (MI) (ASTM D 1238, 190 °C, 2.16 kg): 2.0 to 5.5 g / 10 min

[0060] More specifically, PBAT may have a melting temperature of 100 °C or more, or 105 °C or more, or 110 °C or more and 140 °C or less, or 135 °C or less, or 130 °C or less, or 125 °C or less, or 120 °C or less.

[0061] Meanwhile, in the present disclosure, the melting temperature of PBAT can be measured using a differential scanning calorimeter (DSC). Specifically, a differential scanning calorimeter (DSC, TA200) manufactured by TA Instruments (New Castle, Delaware, USA) is used to raise the temperature from -100°C to 200°C at a rate of 10°C / min and hold it at 200°C for 1 minute, then lower the temperature from 200°C to -100°C at a rate of 10°C / min and hold it for 1 minute. When the temperature is raised from -100°C to 200°C again at a rate of 10°C / min (the second cycle), the melting temperature is measured. The inflection point in the second heating segment of the obtained DSC differential temperature curve is determined as the melting temperature.

[0062] In addition, the melt index (MI) of PBAT (ASTM D 1238, 190°C, 2.16 kg) can be 2.0 g / 10 min or more, or 2.2 g / 10 min or more, or 2.5 g / 10 min or more and 5.5 g / 10 min or less, or 5.0 g / 10 min or less, or 4.9 g / 10 min or less.

[0063] When PBAT further meets the aforementioned requirements for melting temperature and melt index, it can be more advantageous in terms of biodegradability.

[0064] In addition, in the resin composition according to the present disclosure, the maleic anhydride grafted polyolefin elastomer (MAH-g-POE) is a compound in which maleic anhydride (MAH) is graft copolymerized to the polyolefin elastomer (POE), and can improve the compatibility and impact strength of the resin composition.

[0065] POE can specifically be a polypropylene elastomer, a polyethylene elastomer, a polyethylene-propylene elastomer, an ethylene-propylene-diene monomer elastomer, a polyethylene-1-pentene elastomer, a polyethylene-1-hexene elastomer, a polyethylene-1-heptene elastomer, or a polyethylene-1-octene elastomer, etc. More specifically, MAH-g-POE can be a maleic anhydride grafted polypropylene elastomer (MAH-g-PP), a maleic anhydride grafted polyethylene elastomer (MAH-g-PE), or a maleic anhydride grafted ethylene-propylene-diene monomer elastomer (MAH-g-EPDM), and a mixture of two or more of them can be used.

[0066] In addition, based on the total weight of 100 parts by weight of PBAT and Meso PLA, the content of MAH-g-POE can be from 0.1 part by weight to 1.5 parts by weight. More specifically, based on the total weight of 100 parts by weight of PBAT and Meso PLA, it can be included in an amount of 0.1 part by weight or more, or 0.3 part by weight or more, or 0.5 part by weight or more and 1.5 parts by weight or less, or 1.0 part by weight or less, or 0.8 part by weight or less.

[0067] In addition, the weight-average molecular weight (Mw) of MAH-g-POE can be 100,000 g / mol or more, or 110,000 g / mol or more, or 115,000 g / mol or more, or 116,000 g / mol or more and 130,000 g / mol or less, or 125,000 g / mol or less, or 120,000 g / mol or less.

[0068] When MAH-g-POE further meets the above requirements for the Mw range, it may be more advantageous in terms of the compatibility of the resin composition and the improvement of impact strength and mechanical properties.

[0069] Meanwhile, in the present disclosure, the weight-average molecular weight (Mw) of MAH-g-POE can be measured by GPC (gel permeation chromatography).

[0070] Specifically, in the present disclosure, as the gel permeation chromatography (GPC) apparatus, a Waters PL-GPC220 apparatus is used, and a Polymer Laboratories PLgel MIX-B 300 mm column is used. Among them, the measurement temperature is 160 °C. 1,2,4-Trichlorobenzene is used as the solvent, and the flow rate is 1 mL / min. Using a GPC analysis apparatus (PL-GP220), each MAH-g-POE sample is pretreated by dissolving it in 1,2,4-trichlorobenzene containing 0.0125% BHT (2,6-bis(1,1-dimethylethyl)-4-methylphenol) at 160 °C for 10 hours, and prepared at a concentration of 10 mg / 10 mL, and then fed in an amount of 200 μL. Using a calibration curve formed by polystyrene standard samples, the Mw value is obtained. Nine polystyrene standard samples with weight-average molecular weights of 2000 g / mol, 10,000 g / mol, 30,000 g / mol, 70,000 g / mol, 200,000 g / mol, 700,000 g / mol, 2,000,000 g / mol, 4,000,000 g / mol, and 10,000,000 g / mol are used.

[0071] In addition, the resin composition according to the present invention may be composed of PBAT, Meso PLA, and MAH-g-POE as resin components or polymer components.

[0072] In addition, the resin composition according to the present disclosure may further contain other additives. As additives, those commonly used in the field of thermoplastic polymers when molding resin compositions may be used without specific limitation.

[0073] The additives may include heat stabilizers, ultraviolet stabilizers, inorganic fillers, lubricants, etc.

[0074] In addition, based on the total weight of 100 parts by weight of PBAT and Meso PLA, the content of the additives may be from 1 part by weight to 30 parts by weight.

[0075] The present invention also provides a biodegradable resin product containing the above resin composition.

[0076] In addition, the biodegradable resin product may be a biodegradable film.

[0077] Measured according to the ISO 527 standard, the tensile strength of the biodegradable resin product in the MD (machine direction or die direction) may be 300 kgf / cm 2 or more. More specifically, the MD tensile strength of the biodegradable resin product may be 300 kgf / cm 2 or more, or 310 kgf / cm 2 or more, or 330 kgf / cm 2 or more, or 350 kgf / cm 2 or more, and 500 kgf / cm 2 or less, or 400 kgf / cm 2 or less, or 380 kgf / cm 2 or less.

[0078] In addition, the MD elongation at break of the biodegradable resin product measured according to the ISO 527 standard may be 500% or more. Specifically, the elongation at break of the biodegradable resin product in the MD may be 500% or more, or 530% or more, or 540% or more, or 600% or more, and 1000% or less, or 800% or less, or 700% or less.

[0079] In addition, the MD tensile modulus of the biodegradable resin product measured according to ISO 527 may be 1600 kgf / cm 2 or more. Specifically, it may be 1600 kgf / cm 2 or more, or 1700 kgf / cm 23000 kgf / cm or more 2 15000 kgf / cm or less and more than 3000 kgf / cm 2 12000 kgf / cm or less 2

[0080] In addition, after the biodegradable resin product is exposed to distilled water at 50°C to 60°C for 192 hours, the hydrolysis viscosity reduction rate calculated according to the following Equation 1 is 70% or more. More specifically, it may be 70% or more, or 80% or more, and may be 100% or less, or 90% or less.

[0081] [Equation 1]

[0082] Hydrolysis viscosity reduction rate (%) = [(Vo - Vf) / Vo] × 100

[0083] In the equation, Vo represents the zero-shear viscosity of the product before the hydrolysis experiment, and

[0084] Vf represents the zero-shear viscosity of the product after the hydrolysis experiment of being exposed to distilled water at 50°C to 60°C for 192 hours.

[0085] In addition, the biodegradable resin product may have a biodegradability of 45% or more, or 49% or more, measured according to the standard biodegradability test ISO14855.

[0086] Due to this excellent mechanical property and biodegradability, it can be used as a covering film or packaging material, etc.

[0087] Advantages of the Invention

[0088] The resin composition of the present disclosure has excellent mechanical properties and can achieve high biodegradability. Description of the Drawings

[0089] Figure 1a is a photograph of the film before the biodegradability evaluation experiment of the film manufactured in Example 1, Figure 1b is a photograph of the degradability of the film 12 weeks after the biodegradability evaluation experiment.

[0090] Figure 2a is a photograph of the film before the biodegradability evaluation experiment of the film manufactured in Comparative Example 1, Figure 2b is a photograph of the degradability of the film 12 weeks after the biodegradability evaluation experiment.

[0091] Figure 3a is a photograph of the film before the biodegradability evaluation experiment of the film manufactured in Comparative Example 2, Figure 3b is a photograph of the degradability of the film 12 weeks after the biodegradability evaluation experiment. ​

[0092] Figure 4 Presents the observation photos of the biodegradability of the membranes during the enzyme screening experiments by the dipping method for the membranes of Example 1, 2 and Comparative Example 1, 2.

[0093] Figure 5 Presents the observation photos of the biodegradability of the membranes during the enzyme screening experiments by the spraying method for the membranes of Example 3 to 6 and Comparative Example 3 and 4. Detailed Description of the Invention

[0094] Hereinafter, preferred embodiments will be given to assist in understanding the present invention. However, the following embodiments are provided only for better understanding of the present invention, and the scope of the present invention is not limited thereto.

[0095] Hereinafter, the compounds used in the examples and comparative examples are as follows:

[0096] PBAT-1: ECOFLEX from BASF TM (Melting temperature: 110 - 120 °C; MI (ASTM D1238, 190 °C, 2.16 kg): 2.7 - 4.9 g / 10 min)

[0097] PBAT-2: SF1000 from LG Chem Ltd. TM (Melting temperature: 110 - 130 °C; MI (ASTM D 1238, 190 °C, 2.16 kg): 2.0 - 5.0 g / 10 min)

[0098] Polylactic acid (PLLA): LX-175 from Total Corbion TM (Density (ISO 1183): 1.24 g / cm 3 , MFI (ISO 1133-11, 190 °C 2.16 kg): 3.00 g / 10 min)

[0099] meso-Polylactic acid (Meso PLA): EXT403M from Bio valore TM (Density (ISO 1183): 1.24 g / ml, MFI (ISO 1133-11, 190 °C 2.16 kg): 9 g / 10 min)

[0100] Maleic anhydride grafted polyolefin elastomer: FUSABOND N493 manufactured by DOW TM (Weight average molecular weight (Mw): 116000 g / mol)

[0101] Example 1

[0102] In a twin-screw extruder (die diameter = 32 mm), PBAT-1, MesoPLA, and POE-g-MAH were added in the composition ratios described in Table 1 below, and extrusion was carried out under the conditions of a barrel temperature of 140 °C, a feed rate of 30 kg / hr to 50 kg / hr, and 300 rpm to prepare a resin composition in the form of pellets.

[0103] Example 2

[0104] In a twin-screw extruder (die diameter = 32 mm), PBAT-1, MesoPLA, and POE-g-MAH were added in the composition ratios described in Table 1 below, and extrusion was carried out under the conditions of a barrel temperature of 200 °C, a feed rate of 30 kg / hr to 50 kg / hr, and 300 rpm to prepare a resin composition in the form of pellets.

[0105] Examples 3 to 6

[0106] A resin composition was prepared by the same method as in Example 1, except that the addition amounts and the types of constituent elements were changed as described in Table 1 below.

[0107] Comparative Example 1

[0108] A resin composition was prepared by the same method as in Example 1, except that PLLA was used instead of Meso PLA.

[0109] Comparative Example 2

[0110] A commercially available ecovio product manufactured by BASF was used. TM Product.

[0111] Comparative Examples 3 and 4

[0112] A resin composition was prepared by the same method as in Example 1, except that the addition amounts and the types of constituent elements were changed as described in Table 1 below.

[0113] [Table 1]

[0114]

[0115] In Table 1, wt% a Based on the total weight of Resin A and Resin B, parts by weight b are based on 100 parts by weight of the total weight of Resin A and Resin B.

[0116] Experimental Example 1

[0117] The resin compositions prepared in the examples and comparative examples were used to manufacture films as follows, and the properties were evaluated as follows. The results are shown in Table 2 below.

[0118] (1) Manufacture of film

[0119] Using a single-screw extruder (Blown Film M / C, 19 pie, L / D = 25), the resin composition pellets prepared in the examples and comparative examples were molded to a thickness of 0.05 mm at an extrusion temperature of 160°C to 170°C to produce a blown film. Among them, the blow-up ratio was 1.8 and the line speed was 5 m / min.

[0120] (2) Tensile strength, elongation at break, and tensile modulus

[0121] For the films of the examples and comparative examples manufactured above, the MD tensile strength, elongation at break, and tensile modulus were measured respectively using a universal testing machine (Quasur TM 50, manufactured by GALDABINI) according to ISO 527. Among them, samples were prepared in the form of bars (width × height = 10 mm × 150 mm).

[0122] [Table 2]

[0123] <![CDATA[Tensile strength (kgf / cm 2 )]]> Elongation at break (%) <![CDATA[Tensile modulus (kgf / cm 2 )]]> Example 1 346 663 1760 Example 2 302 651 1682 Example 3 323 617 3608 Example 4 315 540 5187 Example 5 354 538 7865 Example 6 360 507 10711 Comparative Example 1 305 535 1809 Comparative Example 2 299 480 2813 Comparative Example 3 322 466 4019 Comparative Example 4 263 3 13348

[0124] Experimental Example 2

[0125] For the films of the examples and comparative examples manufactured in Experimental Example 1, the hydrolysis viscosity reduction rate was measured.

[0126] Specifically, each of the films of Examples 1 and 2 and Comparative Example 1 was pressed to produce a sample with a thickness of 2 mm, and the manufactured sample was immersed in distilled water at 58°C for 192 hours for exposure.

[0127] For the exposed samples, a rheometer (EC Twist 502 type, manufactured by Anton paar) was used to measure the shear viscosity respectively under the conditions of 190°C and 0.1 rad / sec to 100 rad / sec to obtain each zero-shear viscosity value, and the hydrolysis (biodegradation physical behavior) viscosity reduction rate was calculated according to the following Equation 1.

[0128] [Equation 1]

[0129] Hydrolysis viscosity reduction rate (%) = [(Vo - Vf) / Vo] × 100

[0130] In the equation, Vo represents the zero-shear viscosity of the product before the hydrolysis experiment, and

[0131] Vf represents the zero-shear viscosity of the product after the hydrolysis experiment of being exposed to distilled water at 50°C to 60°C for 192 hours.

[0132] Specifically, in this experimental example, Vf is the zero-shear viscosity of the film after being exposed to distilled water at 58°C for 192 hours.

[0133] [Table 3]

[0134] Hydrolysis viscosity reduction rate (%) Example 1 81 Example 2 74 Comparative Example 1 60

[0135] Experimental Example 3

[0136] The biodegradability test was carried out according to the standard biodegradability test ISO 14855.

[0137] Specifically, each of the films of Example 1 and Comparative Examples 1 and 2 prepared in Experimental Example 1 was cut into a width × height = 2.5 cm × 2.5 cm and a thickness of 0.02 mm to prepare samples. In order to observe the change in the surface area of the samples, the samples were fixed to a non-biodegradable plastic mold. Three samples were prepared for three tests.

[0138] The compost for the aerobic biodegradation test was prepared with the composition shown in Table 4 below as described in the standard, and a container of 30 cm × 20 cm × 10 cm (l × w × h) was used.

[0139] [Table 4]

[0140]

[0141] The dry solid content and the volatile solid content were calculated according to the following formula. Among them, the wet solid weight (mat w ) was measured at room temperature, and the dry solid weight (mat d ) was calculated from the amount of solid obtained after treatment in a drying oven at a temperature of 110 °C for more than 30 minutes.

[0142] The non-volatile solid weight (mat nv ) was calculated from the amount of residue obtained after treatment in a drying oven at a temperature of 550 °C for more than 50 minutes.

[0143] Dry solid content (%) = mat d / mat w × 100

[0144] Volatile solid content (relative to wet solid weight) (%) = [(mat d - mat wnv ) / mat w × 100

[0145] Volatile solid content (relative to dry solid weight) (%) = [(mat d - mat wnv ) / mat d × 100

[0146] For biodegradability, according to "KST ISO 20200:2004 Plastics - Determination of the biodegradability of plastic materials under composting conditions in laboratory-scale tests", the compost biodegradability test was carried out for 12 weeks under the reactor conditions (25 ± 2 °C) that can maintain aerobic conditions.

[0147] After the test, the samples were filtered using standard sieve sizes of 10 mm, 5 mm, and 2 mm, then washed and dried at 40 ± 2 °C.

[0148] The plastic materials filtered through the sieve during the filtration process were regarded as non-degradable materials, and the materials passing through the sieve were regarded as degraded. The biodegradability D was calculated according to the following Equation 2. The results are shown in Table 5.

[0149] [Equation 2]

[0150] Biodegradability D (%) = [(m i - m f ) / m i × 100

[0151] In the equation, m i is the initial dry solid weight (g) of the sample, and

[0152] m f is the dry solid weight (g) of the remaining sample (non-degradable material) filtered through the sieve.

[0153] In addition, during, before, and 12 weeks after the biodegradability evaluation experiment of the films prepared in Example 1 and Comparative Examples 1 and 2, the degradability of the films was observed, and the results are shown in Figures 1a to 3b .

[0154] [Table 5]

[0155] <![CDATA[m i (g)]]> <![CDATA[m f (g)]]> Biodegradability (%) Example 1 5.04g 2.52g 49.9 Comparative Example 1 5.04g 2.94g 41.6 Comparative Example 2 5.03g 3.87g 23.3

[0156] When the reduction in the total volatile solid content between the initial synthetic waste in each reaction tank and the compost obtained at the end of the test is more than 30%, and the difference in biodegradability in three repeated tests is less than 10%, the test is considered valid. Considering this, the film made of the resin composition of the example showed a biodegradability of 49.9%, thus confirming that the resin composition of the example has excellent biodegradability.

[0157] Experimental Example 4

[0158] For the films of the examples and comparative examples manufactured in Experimental Example 1, the enzyme screening by the dipping method was carried out as follows, and the biodegradability was evaluated according to the results.

[0159] (1) Sample preparation

[0160] Specifically, the films of Example 1, 2 and Comparative Example 1, 2 with a thickness of 0.05 mm produced in Experimental Example 1 were each cut into a width × height = 1 cm × 1 cm to prepare samples, which were then disinfected with ethanol.

[0161] (2) Preparation of hydrolase solution

[0162] The following 2 kinds of lipases, 2 kinds of cutinases and 1 kind of α - amylase were mixed into 1 ml of 1X phosphate buffered saline (PBS) to prepare a hydrolase solution.

[0163] 1000 units of Lipase Rhizopus Oryzae

[0164] 3000 units of Lipase Pseudomonas Cepacia

[0165] 2000 units of Cutinase Aspergillus Oryzae

[0166] 1500 units of Cutinase Humicola Insolens

[0167] 1500 units of α - amylase Bacillus Licheniformis

[0168] (3) Biodegradability evaluation

[0169] The biodegradability assessment was carried out as follows under the conditions of 37 °C and 760 mmHg.

[0170] 0.5 ml of the hydrolase solution was added to one well of a 24 - well plate, and the two samples of (1) were immersed for 7 days. Immediately after immersion (0 day), 5 days after immersion (5 days) and 7 days after immersion (7 days), the modes of collapse of the samples and detachment of the sheets were observed respectively. The results are shown in Figure 4 in.

[0171] As a result of the experiment, compared with Comparative Example 2, the films of Example 1 and 2 were rapidly biodegradable. Considering that the film of Comparative Example 2 is a home composting certified product, it can be expected that the films made of the resin composition of the present disclosure can also exhibit high biodegradability under home and soil composting conditions.

[0172] Experimental Example 5

[0173] For the films of the examples and comparative examples produced in Experimental Example 1, enzyme screening by the spraying method was carried out as follows, and the biodegradability was evaluated according to the results.

[0174] (1) Preparation of culture medium

[0175] A circular 1% agar plate with a diameter of 90 mm was prepared by the method of preparing culture dish medium.

[0176] In a 2000 ml conical flask, 10 g of agar (manufacturing company: BD Difco, product name: Bacto Agar, product number: 214010) and 1000 ml of distilled water were used to prepare a solution. The solution was placed in an autoclave and sterilized at a temperature of 121 °C and a pressure of 0.1 MPa for 15 minutes. 10 ml of the sterilized solution was aliquoted into each circular sterilized culture dish with a diameter of 90 mm to prepare the culture medium.

[0177] (2) Preparation of resin solution

[0178] Each of the membranes of Examples 3 to 6 and Comparative Examples 3 and 4 prepared in Experimental Example 1 was dissolved in 20 ml of chloroform to a concentration of 1 wt% to prepare a resin solution.

[0179] (3) Preparation of hydrolase solution

[0180] Two kinds of lipases and two kinds of cutinases as follows were mixed in 1 ml of 1X phosphate buffered saline (PBS) to prepare a hydrolase solution (stock solution). In addition, a 1 / 10 dilution solution of the stock solution was prepared.

[0181] 1000 units of Lipase Rhizopus Oryzae

[0182] 3000 units of Lipase Pseudomonas Cepacia

[0183] 2000 units of Cutinase Aspergillus Oryzae

[0184] 1500 units of Cutinase Humicola Insolens

[0185] (4) Evaluation of biodegradability

[0186] On the agar plate in (1), 6 mL of the resin solution prepared in (2) was evenly sprayed and dried at room temperature for about 10 minutes to volatilize the solvent, and a specimen with an average thickness of 0.7 μm was prepared. The average thickness of the sample was calculated from the roughness of the sample measured before and after spraying using an optical profilometer (model name: NewView TM 8300, Zygo Corporation).

[0187] Next, 5 μL each of the stock solution and 1 / 10 dilution of the hydrolytic enzyme solution of (3) was added dropwise to each sample at 4 points. Thereafter, the area of the transparent region formed by the degradation of the spray resin by the hydrolytic enzyme solution and the degree of transparency thereof were observed with the naked eye. The experimental results are as Figure 5 shown.

[0188] Meanwhile, the entire process of biodegradability evaluation was carried out at 28 °C and atmospheric pressure (760 ± 20 Torr).

[0189] As a result of the experiment, in Example 6 and Comparative Example 4, a transparent region appeared 1 hour after treatment, in Example 4 and Example 5, a transparent region appeared 1.5 hours after treatment, in Example 3, a transparent region appeared 2.5 hours after treatment, and in Comparative Example 3, a transparent region appeared 8 hours after treatment.

Claims

1. A resin composition, comprising: Polybutylene adipate-co-butylene terephthalate, meso-Polylactic acid, and maleic anhydride-grafted polyolefin elastomer, Among them, The resin composition contains the polybutylene adipate-co-butylene terephthalate and the meso-poly lactic acid in a weight ratio of 9.0:1.0 to 6.0:4.

0.

2. The resin composition according to claim 1, wherein, The meso-poly lactic acid is a random polymer containing repeating units represented by the following Chemical Formula 1: [Chemical Formula 1] In Chemical Formula 1, n is an integer of 2 or more.

3. The resin composition according to claim 1, wherein, The meso-poly lactic acid satisfies the following conditions (a1) and (a2): (a1) Density (ISO1183): 1.15 g / ml to 1.35 g / ml (a2) Melt flow index (MFI) (ISO1133-11, 190 °C, 2.16 kg): 3 g / 10 min to 15 g / 10 min.

4. The resin composition according to claim 1, wherein, The polybutylene adipate-co-butylene terephthalate satisfies the following conditions (b1) and (b2): (b1) Melting temperature: 100 °C to 140 °C (b2) Melt index (MI) (ASTM D 1238, 190 °C, 2.16 kg): 2.0 g / 10 min to 5.5 g / 10 min.

5. The resin composition according to claim 1, wherein, Based on the total weight of 100 parts by weight of the polybutylene adipate-co-butylene terephthalate and the meso-poly lactic acid, the content of the maleic anhydride-grafted polyolefin elastomer is 0.1 part by weight to 1.5 parts by weight.

6. The resin composition according to claim 1, wherein The maleic anhydride-grafted polyolefin elastomer has a weight average molecular weight of 100,000 g / mol to 130,000 g / mol.

7. A biodegradable resin product, comprising the resin composition according to any one of claims 1 to 6.

8. The biodegradable resin product according to claim 7, wherein, The MD tensile strength measured according to ISO 527 is 300 kgf / cm 2 or more.

9. The biodegradable resin product according to claim 7, wherein, The MD elongation rate measured according to ISO 527 is 500% or more.

10. The biodegradable resin product according to claim 7, wherein, The MD tensile modulus measured according to ISO 527 is 1600 kgf / cm 2 or more.

11. The biodegradable resin product according to claim 7, wherein, After exposure to distilled water at 50 °C to 60 °C for 192 hours, the hydrolysis viscosity reduction rate calculated according to the following Equation 1 is 70% or more. [Equation 1] Hydrolysis viscosity reduction rate (%) = [(Vo - Vf) / Vo] × 100 In this equation, Vo represents the zero-shear viscosity of the product before the hydrolysis experiment, and Vf represents the zero-shear viscosity of the product after the hydrolysis experiment of exposure to the distilled water at 50 °C to 60 °C for 192 hours.

12. The biodegradable resin product according to claim 7, wherein, The biodegradability measured according to the standard biodegradability test ISO14855 is 45% or more.

13. The biodegradable resin product according to claim 7, wherein, The product is a biodegradable film.

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