Resin composition and biodegradable resin product comprising same

Abstract

The present invention relates to a resin composition and a biodegradable resin product comprising same. The resin composition contains a polybutylene adipate-co-terephthalate, a meso-polylactic acid, and a maleic anhydride-grafted polyolefin elastomer, and the weight ratio between the polybutylene adipate-co-terephthalate and the meso-polylactic acid is 9.0:1.0 to 6.0:4.0. Accordingly, the resin composition has excellent mechanical properties and is highly biodegradable.

Description

Resin composition and biodegradable resin molded article containing the same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0129095, filed September 26, 2023, and Korean Patent Application No. 10-2024-0130452, filed September 26, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a resin composition and a biodegradable resin molded product comprising the same.

[0004]

[0005] Thermoplastic polymer resins have excellent mechanical and chemical properties and are used in a variety of fields, including drinking water containers, medical and food packaging, food containers, automotive molded parts, and agricultural vinyl.

[0006] Thermoplastic polymer resins, especially polyethylene films, have excellent mechanical properties, are harmless to the human body, and can be continuously deformed when heat is applied, so they are widely used in hot sealing bags for food packaging and agricultural mulching films.

[0007] Hot sealing bags for food packaging are widely used for vacuum packaging of foods, etc., and polyethylene films, which can achieve excellent bonding strength even at low sealing temperatures, are widely used.

[0008] The agricultural film mentioned above is widely used in mulching farming. Mulching refers to the material used to cover the soil surface when growing crops. Covering the topsoil with various types of materials can inhibit weed growth, prevent pests and diseases, and thus reduce pesticide use. It also helps regulate soil temperature, promotes the growth of beneficial bacteria, prevents soil erosion, and maintains soil moisture.

[0009] Examples of such mulching materials include crop leaves such as straw or grass, polyolefin films, and synthetic resins such as polyethylene films are commonly used.

[0010] However, polyethylene film, widely used as hot-sealing bags for food packaging and mulching materials, does not decompose in the natural environment and has limitations in recycling. Recently, it has become known that discarded plastics, such as polyethylene film, are flowing into the ocean, where they are broken down into tiny microplastics by ocean currents and sunlight.

[0011] Currently, it is known that countless amounts of these microplastics are floating in the ocean, numbering from tens to hundreds of billions, and they enter the bodies of marine life and accumulate within the ecosystem, affecting the entire food chain.

[0012] Therefore, research into alternatives to conventional thermoplastics is necessary.

[0013] To solve this problem, the development of mulching films made of photodegradable or biodegradable polymers has been actively attempted recently, but there are still problems such as insufficient biodegradability and mechanical properties falling short of those of existing polyethylene films.

[0014]

[0015] The present specification seeks to provide a resin composition having excellent mechanical properties and high biodegradability.

[0016] In addition, the present specification seeks to provide a biodegradable resin molded product comprising the resin composition.

[0017]

[0018] This specification,

[0019] polybutylene adipate-co-terephthalate (poly[(butylene adipate)-co-terephthalate]; PBAT),

[0020] Meso polylactic acid (Meso PLA), and

[0021] Containing maleic anhydride-graft-polyolefin elastomers,

[0022] A resin composition is provided, comprising the above polybutylene adipate-co-terephthalate and meso polylactic acid in a weight ratio of 9.0:1.0 to 6.0:4.0.

[0023]

[0024] In addition, the present specification provides a biodegradable resin molded product comprising the resin composition.

[0025]

[0026] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the invention.

[0027] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0028] In this specification, the terms “comprise,” “include,” or “have” are intended to describe a feature, number, step, component, or combination thereof implemented, and do not exclude the possibility of one or more other features, numbers, steps, components, combinations, or additions thereof, unless otherwise stated.

[0029] Also, in this specification, unless otherwise specified, room temperature is 25±5℃ and room pressure is 760±20 torr.

[0030] The present invention is susceptible to various modifications and takes various forms. Specific embodiments are illustrated and described in detail below. However, this does not limit the invention to a specific disclosed form, but rather encompasses all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0031] Hereinafter, the present invention will be described in detail.

[0032]

[0033] The inventors of the present invention have discovered that when producing a resin composition using polybutylene adipate-co-terephthalate (PBAT) and meso polylactic acid (Meso PLA), when meso polylactic acid is mixed and used in an optimal weight ratio with respect to the polybutylene adipate-co-terephthalate and when a maleic anhydride-graft-polyolefin elastomer is used, high biodegradability can be realized along with excellent mechanical properties such as tensile strength, elongation, and tensile modulus, and thus completed the present invention.

[0034]

[0035] PBAT is a biodegradable polymer that exhibits high elongation at break and ductility. However, its mechanical properties, such as low tensile strength and tensile modulus, limit its application. To overcome these limitations, blending PBAT with other biodegradable polymers can expand its application range and improve its properties.

[0036]

[0037] Meanwhile, poly(lactic acid) (PLA) or polylactide is a biodegradable polymer with high tensile strength and tensile modulus. However, PLA is biodegradable only under certain biodegradation conditions, specifically industrial composting conditions, and its biodegradability is limited under other conditions. These PLA characteristics may also affect the biodegradability of PBAT / PLA blends.

[0038]

[0039] Accordingly, a resin composition according to one aspect of the present invention can exhibit significantly improved biodegradability along with excellent mechanical properties by including Meso PLA in an optimal weight ratio instead of conventional PLA with respect to PBAT.

[0040]

[0041] Specifically, a resin composition according to one aspect of the present invention comprises polybutylene adipate-co-terephthalate (PBAT) and meso polylactic acid (Meso PLA) in a weight ratio of 9.0:1.0 to 6.0:4.0.

[0042]

[0043] More specifically, the weight ratio of PBAT:Meso PLA in the resin composition may 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. Here, the terms “or more” and “or less” are based on the content of PBAT.

[0044]

[0045] When the weight ratio of the PBAT:Meso PLA exceeds 9.0:1.0 and the content of Meso PLA to PBAT is too low, the resin composition does not exhibit sufficient biodegradability. In addition, when the weight ratio of the PBAT:Meso PLA is less than 6.0:4.0 and the content of Meso PLA to PBAT is too high, the rigidity increases and the elongation of the resin composition may decrease. In particular, when the resin composition is processed into a biodegradable film or the like, the processability may decrease, and when used for purposes such as a mulching film, it may be difficult to implement the required physical properties. In this case, the above-mentioned 'exceeds' and 'is less than' are based on the content of PBAT.

[0046]

[0047] In addition, under the condition that the weight ratio range of the PBAT and Meso PLA is satisfied, the Meso PLA may be included in an amount of 7.0 to 75.0 parts by weight based on 100 parts by weight of PBAT. More specifically, the Meso PLA 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 based on 100 parts by weight of PBAT.

[0048]

[0049] In this specification, “polylactic acid” refers to a polymer of lactide and is used with the same meaning as “polylactide” and “PLA.”

[0050] The lactide or lactide monomer may be L-lactide derived from two L-lactic acid molecules; D-lactide derived from two 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 thereof. It may also be racemic lactide (rac-Lactide), which is a 50:50 mixture of L-lactide and D-lactide. Accordingly, the PLA in the present specification may be a lactide polymer selected from the group comprising L-lactide, D-lactide, meso lactide, racemic lactide, and any mixture of two or more thereof.

[0051]

[0052] Lactide can synthesize PLA with various structures through ring-opening polymerization according to stereoregulation.

[0053] Poly(L-lactic acid), a polymer of L-lactide, and Poly(D-lactic acid), a polymer of D-lactide, are structurally identical. It is the most crystalline of PLA and exhibits semi-crystalline properties. As the proportion of D-lactide in the PLA structure increases, it exhibits amorphous characteristics, but if the content of D-lactide in the PLA structure exceeds 10%, processability deteriorates. Accordingly, PLA generally has a high proportion of L-lactide. Commercially available products typically have an L-lactide content of 95% or more and a D-lactide content of 5% or less.

[0054]

[0055] Meanwhile, the solid-state morphology, degree of crystallinity, and primary chemical structure of PLA affect the degradation characteristics of PLA.

[0056] Solid-state morphology refers to the shape, thickness, surface area, etc. of PLA, and among these, the shape is very important to induce efficient decomposition.

[0057] The crystallinity of PLA is also an important factor affecting the decomposition characteristics of PLA.

[0058] Typically, PLA degradation begins with the amorphous region as water (H2O) diffuses into the PLA, followed by random hydrolysis, resulting in the decomposition of PLA from polymer to oligomer, followed by fragmentation, and then, through more extensive hydrolysis, conversion to CO2 and H2O through diffusion and metabolism. Accordingly, amorphous PLA may exhibit superior degradation characteristics than crystalline PLA.

[0059] The primary chemical structure of PLA, specifically the presence of functional groups and the hydrophilicity-hydrophobicity balance, also affect the decomposition characteristics of PLA.

[0060]

[0061] Meso PLA in the present invention is a polymer manufactured by polymerization of meso-lactide, and specifically, may be an amorphous polymer including a repeating unit represented by the following chemical formula 1:

[0062] [Chemical Formula 1]

[0063]

[0064] In the above chemical formula 1, n is an integer greater than or equal to 2.

[0065]

[0066] Additionally, Meso PLA may satisfy the following conditions (a1) and (a2).

[0067] (a1) Density (ISO 1183): 1.15 to 1.35 g / ml

[0068] (a2) Melt flow index (MFI) (ISO 1133-11, 190℃, 2.16kg): 3 to 15 g / 10min

[0069]

[0070] More specifically, the density (ISO 1183) of the above Meso PLA is 1.15 g / ml. or more than 1.20 g / ml, or more than 1.22 g / ml, or more than 1.24 g / ml or less than or equal to 1.35 g / ml, or less than or equal to 1.30 g / ml, or less than or equal to 1.25 g / ml It could be as follows:

[0071]

[0072] In addition, the Meso PLA may have a melt flow index (MFI) (ISO 1133-11, 190°C, 2.16kg) of 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.

[0073]

[0074] When Meso PLA satisfies the above-mentioned density and melt flow index conditions, it exhibits better mechanical properties such as tensile strength and tensile elastic modulus, and can be more advantageous in improving the biodegradability of the resin composition.

[0075]

[0076] In the resin composition according to the present invention, Meso PLA may be composed only of repeating units represented by the above chemical formula 1. That is, it may be a Meso lactide homopolymer that does not contain repeating units derived from other monomers other than the repeating units represented by the above chemical formula 1.

[0077]

[0078] In addition, in the resin composition according to the present invention, the polybutylene adipate-co-terephthalate (PBAT) may satisfy the following conditions (b1) and (b2).

[0079] (b1) Melting temperature (Tm): 100 to 140 ℃

[0080] (b2) Melting index (MI) (ASTM D 1238, 190℃, 2.16kg): 2.0 to 5.5 g / 10min

[0081]

[0082] More specifically, the melting temperature of the PBAT may be 100°C or higher, or 105°C or higher, or 110°C or higher, and 140°C or lower, or 135°C or lower, or 130°C or lower, or 125°C or lower, or 120°C or lower.

[0083]

[0084] Meanwhile, in the present invention, the melting temperature of PBAT can be measured using a differential scanning calorimeter (DSC). Specifically, the temperature was increased from -100°C to 200°C at a rate of 10°C / min using a differential scanning calorimeter (DSC, TA2000) from TA Instruments (New Castle, Delaware, USA), maintained at 200°C for 1 min, and then decreased from 200°C to -100°C at a rate of 10°C / min and maintained for 1 min. The melting temperature was measured while again increasing from -100°C to 200°C at a rate of 10°C / min (2nd cycle). The melting temperature was determined as the inflection point in the second temperature-rising section of the obtained DSC differential temperature curve.

[0085]

[0086] In addition, the PBAT may have a melting index (MI) (ASTM D 1238, 190°C, 2.16 kg) of 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.

[0087]

[0088] If PBAT satisfies the above-mentioned melting temperature and melting index conditions better, it may be more advantageous in terms of biodegradability.

[0089]

[0090] In addition, in the resin composition according to the present invention, maleic anhydride-grafted polyolefin elastomer (MAH-g-POE) is a compound in which maleic anhydride (MAH) is grafted onto polyolefin elastomer (POE), and can improve the compatibility and impact strength of the resin composition.

[0091]

[0092] Specifically, the POE may be a polypropylene elastomer, a polyethylene elastomer, a polyethylenepropylene 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. More specifically, the MAH-g-POE may be a maleic anhydride-graft-polypropylene elastomer (MAH-g-PP), a maleic anhydride-graft-polyethylene elastomer (MAH-g-PE), or a maleic anhydride-graft-ethylene-propylene-diene monomer elastomer (MAH-g-EPDM), and any one thereof or a mixture of two or more thereof may be used.

[0093]

[0094] In addition, the MAH-g-POE may be included in an amount of 0.1 to 1.5 parts by weight relative to 100 parts by weight of the total combined weight of the PBAT and Meso PLA. More specifically, the MAH-g-POE may be included in an amount of 0.1 parts by weight or more, or 0.3 parts by weight or more, or 0.5 parts by weight or more, and 1.5 parts by weight or less, or 1.0 parts by weight or less, or 0.8 parts by weight or less relative to 100 parts by weight of the total of the PBAT and Meso PLA.

[0095]

[0096] In addition, the above MAH-g-POE may have a weight average molecular weight (Mw) of 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.

[0097]

[0098] If the above MAH-g-POE further satisfies the Mw condition within the above range, it may be more advantageous in terms of improving the compatibility of the resin composition and the impact strength and mechanical properties.

[0099]

[0100] Meanwhile, in the present invention, the weight average molecular weight (Mw) of MAH-g-POE can be measured through gel permeation chromatography (GPC) analysis.

[0101] Specifically, in the present invention, a Waters PL-GPC220 gel permeation chromatography (GPC) device was used, and a Polymer Laboratories PLgel MIX-B 300 mm column was used. The measurement temperature was 160°C, 1,2,4-trichlorobenzene was used as a solvent, and the flow rate was 1 mL / min. Each MAH-g-POE sample was pretreated by dissolving it in trichlorobenzene (1,2,4-trichlorobenzene) containing 0.0125% dibutylhydroxytoluene (BHT, 2,6-bis(1,1-dimethylethyl)-4-methylphenol) at 160°C for 10 hours using a GPC analysis device (PL-GP220), and then preparing it at a concentration of 10 mg / 10 mL, and then supplying it in an amount of 200 μL. The Mw value was derived using a calibration curve formed using polystyrene standard specimens. The weight-average molecular weights of the polystyrene standard specimens were 2000 g / mol, 10000 g / mol, 30000 g / mol, 70000 g / mol, 200000 g / mol, 700000 g / mol, 2000000 g / mol, 4000000 g / mol, and 10000000 g / mol, which were nine types.

[0102]

[0103] In addition, the resin composition according to the present invention may be composed of the PBAT, Meso PLA, and MAH-g-POE as the resin component or polymer component.

[0104]

[0105] In addition, the resin composition according to the present invention may further include other additives. The additives may be any additive commonly used in the molding of resin compositions within the technical field to which the present invention pertains, i.e., in the field of thermoplastic polymers, without particular limitation.

[0106]

[0107] The above additives may include heat stabilizers, UV stabilizers, inorganic fillers or lubricants.

[0108] And, the additive may be included in an amount of 1 to 30 parts by weight based on 100 parts by weight of the total combined weight of the PBAT and Meso PLA.

[0109]

[0110] In addition, the present specification provides a biodegradable resin molded product comprising the resin composition described above.

[0111]

[0112] And, the biodegradable resin molded product may be a biodegradable film.

[0113]

[0114] The above biodegradable resin molded product has a tensile strength in the MD direction (Machine Direction or Mold direction) of 300 kgf / cm as measured according to the ISO 527 standard. 2 It may be more than that. More specifically, the biodegradable resin molded product has a tensile strength in the MD direction of 300 kgf / cm. 2 or 310 kgf / cm 2 or more than 330 kgf / cm 2 or more than 350 kgf / cm 2 Above, 500 kgf / cm 2 or less, or 400 kgf / cm 2 or less, or 380 kgf / cm 2 It could be as follows:

[0115]

[0116] In addition, the biodegradable resin molded product may have an MD direction elongation at break of 500% or more as measured according to the ISO 527 standard. Specifically, the MD direction elongation at break of the biodegradable resin molded product 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.

[0117]

[0118] And, the biodegradable resin molded product has a tensile modulus in the MD direction of 1600 kgf / cm as measured according to the ISO 527 standard. 2 It can be more than 1600 kgf / cm. Specifically, 2 or 1700 kgf / cm 2 or more than 3000 kgf / cm 2 Above, 15,000 kgf / cm 2 or less, or 12,000 kgf / cm 2 It could be as follows:

[0119]

[0120] In addition, the biodegradable resin molded product may have a hydrolysis viscosity reduction rate of 70% or more, calculated according to the following mathematical formula 1, after exposure to distilled water at 50 to 60°C for 192 hours. More specifically, it is 70% or more, or 80% or more, and 100% or less, or 90% or less.

[0121] [Mathematical Formula 1]

[0122] Hydrolysis viscosity reduction rate (%) = [(Vo-Vf) / Vo] x 100

[0123] In the above equation, Vo is the zero shear viscosity of the molded product before the hydrolysis experiment,

[0124] Vf is the zero shear viscosity of the molded product after a hydrolysis test in which the product is exposed to distilled water at 50 to 60°C for 192 hours.

[0125]

[0126] In addition, the biodegradable resin molded product has a biodegradability of 45% or more, or 49% or more, measured according to the standard biodegradation test standard ISO 14855.

[0127]

[0128] Due to its excellent mechanical properties and biodegradability, it can be used as an agricultural mulching film or packaging material.

[0129]

[0130] The resin composition of the present invention has excellent mechanical properties and can achieve high biodegradability.

[0131]

[0132] Figure 1a is a photograph of the film before the biodegradability evaluation experiment for the film manufactured in Example 1, and Figure 1b is a photograph of the film's decomposition 12 weeks after the biodegradability evaluation experiment.

[0133] Figure 2a is a photograph of the film before the biodegradability evaluation experiment for the film manufactured in Comparative Example 1, and Figure 2b is a photograph of the film's decomposition 12 weeks after the biodegradability evaluation experiment.

[0134] Figure 3a is a photograph of the film before the biodegradability evaluation experiment for the film manufactured in Comparative Example 2, and Figure 3b is a photograph of the film's decomposition 12 weeks after the biodegradability evaluation experiment.

[0135] Figure 4 is a photograph showing the biodegradability of films observed during an enzyme screening experiment using an immersion method for films of Examples 1 and 2 and Comparative Examples 1 and 2.

[0136] Figure 5 is a photograph showing the biodegradability of films observed during an enzyme screening experiment using a spray method for films of Examples 3 to 6 and Comparative Examples 3 and 4.

[0137]

[0138] Hereinafter, preferred examples are presented to aid understanding of the present invention. However, the following examples are provided solely to facilitate understanding of the present invention and are not intended to limit the scope of the present invention.

[0139]

[0140] The compounds used in the following examples and comparative examples are as follows:

[0141] PBAT-1: ECOFLEX™ from BASF (melting temperature: 110-120℃; MI (ASTM D 1238, 190℃, 2.16kg): 2.7-4.9g / 10min)

[0142] PBAT-2: SF1000™ from LG Chem (melting temperature: 110~130℃; MI (ASTM D 1238, 190℃, 2.16kg): 2.0~5.0 g / 10min)

[0143] Polylactic acid (PLLA): LX-175™ from Total Corbion (density (ISO 1183): 1.24 g / cm 3 , MFI (ISO 1133-11, 190 ℃ 2.16kg): 3.00 g / 10min)

[0144] Meso polylactic acid (Meso PLA): EXT 403M™ from Bio valore (Density (ISO 1183): 1.24 g / ml, MFI (ISO 1133-11, 190 ℃ 2.16 kg): 9 g / 10 min)

[0145] Maleic anhydride-graft-polyolefin elastomer: FUSABOND N493™ from DOW (weight-average molecular weight (Mw): 116,000 g / mol)

[0146]

[0147] Example 1

[0148] PBAT-1, Meso PLA, and POE-g-MAH were fed into a twin-screw extruder (die diameter = 32 mm) in the compositions shown in Table 1 below, and extruded under the conditions of a barrel temperature of 140°C, a feed rate of 30 to 50 kg / hr, and 300 rpm, thereby manufacturing a resin composition in the form of pellets.

[0149]

[0150] Example 2

[0151] PBAT-1, Meso PLA, and POE-g-MAH were fed into a twin-screw extruder (die diameter = 32 mm) in the compositions shown in Table 1 below, and extruded under the conditions of a barrel temperature of 200°C, a feed rate of 30 to 50 kg / hr, and 300 rpm, thereby manufacturing a resin composition in the form of pellets.

[0152]

[0153] Examples 3 to 6

[0154] A resin composition was manufactured in the same manner as in Example 1, except that the input amounts and types of the components were changed as described in Table 1 below.

[0155]

[0156] Comparative Example 1

[0157] A resin composition was prepared in the same manner as in Example 1 except that the PLLA was used instead of Meso PLA.

[0158]

[0159] Comparative Example 2

[0160] Commercially available ecovio™ product from BASF was used.

[0161]

[0162] Comparative examples 3 and 4

[0163] A resin composition was manufactured in the same manner as in Example 1, except that the input amounts and types of the components were changed as described in Table 1 below.

[0164]

[0165]

[0166] In the above Table 1, the weight % of a is based on the total combined weight of resin A and resin B, and the weight part of b is based on the total combined weight of resin A and resin B being 100 parts by weight.

[0167]

[0168] Experimental Example 1

[0169] Films were manufactured using the resin compositions prepared in the above examples and comparative examples using the following methods, and their physical properties were evaluated according to the following methods. The results are shown in Table 2 below.

[0170]

[0171] (1) Film manufacturing

[0172] For the pellet-shaped resin compositions manufactured in the above examples and comparative examples, a blown film was manufactured by molding at an extrusion temperature of 160°C to 170°C to a thickness of 0.05 mm using a single screw extruder (Blown Film M / C, 19 pi, L / D=25). At this time, the blown-up ratio was 1.8, and the line speed was 5 m / min.

[0173]

[0174] (2) Tensile strength, elongation and tensile modulus

[0175] For the films of the examples and comparative examples manufactured above, the tensile strength, elongation, and tensile modulus in the MD direction of the film were measured according to the ISO 527 standard using a universal testing machine (QUASUR™ 50, manufactured by GALDABINI). At this time, the specimens were manufactured in the form of a bar (width x length = 10 mm x 150 mm).

[0176]

[0177] Tensile strength (kgf / cm) 2 ) Elongation (%) Tensile modulus (kgf / cm) 2 ) Example 13466631760 Example 23026511682 Example 33236173608 Example 43155405187 Example 53545387865 Example 636050710711 Comparative Example 13055351809 Comparative Example 22994802813 Comparative Example 33224664019 Comparative Example 4263313348

[0178]

[0179] Experimental Example 2

[0180] The hydrolysis viscosity reduction rate was measured for the films of the examples and comparative examples manufactured in the above experimental example 1.

[0181] Specifically, the films of Examples 1 and 2 and Comparative Example 1 were each pressed to produce a specimen with a thickness of 2 mm, and the produced specimen was exposed by immersion in distilled water at 58°C for 192 hours.

[0182] For the exposed specimens, shear viscosity was measured at 190°C and 0.1 to 100 rad / sec using a rheometer of the EC Twist 502 model from Anton Paar, and each zero shear viscosity value was obtained, and the hydrolysis (biodegradation physical behavior) viscosity reduction rate was calculated according to the following mathematical equation 1.

[0183] [Mathematical Formula 1]

[0184] Hydrolysis viscosity reduction rate (%) = [(Vo-Vf) / Vo] x 100

[0185] In the above mathematical expression 1, Vo is the zero shear viscosity of the molded product before the hydrolysis experiment, i.e., the film with an exposure time of 0 hr,

[0186] Vf is the zero shear viscosity of the molded product, i.e., the film with an exposure time of 192 hr, after a hydrolysis test in distilled water at 50 to 60°C for 192 hours.

[0187] Specifically, Vf in this experimental example is the zero shear viscosity of the film after exposure to 58°C and distilled water for 192 hours.

[0188]

[0189] Hydrolysis viscosity reduction rate (%) Example 181 Example 274 Comparative example 160

[0190] Experimental Example 3

[0191] Biodegradability tests were conducted according to the standard biodegradation test standard ISO 14855.

[0192] Specifically, the films of Example 1 and Comparative Examples 1 and 2 manufactured in Experimental Example 1 were cut into a size of 2.5 cm x 2.5 cm (width x length) and 0.02 mm (thickness) to prepare specimens. In order to observe changes in the surface area of ​​the specimens, the specimens were fixed to a non-biodegradable plastic frame. Three specimens were prepared so that three tests could be performed.

[0193] The compost used in the aerobic biodegradability test was made with the same composition as in Table 4 below as suggested in the standard, and a container measuring 30 cm x 20 cm x 10 cm (l x w x h) was used.

[0194] Ingredient dry weight (weight %, based on total dry weight of compost) 40% sawdust, 30% feed, 10% matured fertilizer, 10% corn starch, 5% saccharose, 4% corn germ oil, 1% urea, 100% total

[0195] Dry solids content and volatile solids content were obtained according to the following formulas. Here, wet solids weight (mat w ) was measured at room temperature, and the dry solid weight (mat d ) was obtained from the amount of solid content obtained after treatment at 110℃ in a dry oven for more than 30 minutes.

[0196] Nonvolatile solids weight (mat nv ) was obtained from the amount of residue obtained after treatment at 550℃ in a dry oven for more than 50 minutes.

[0197] Dry solids content (%) = mat d / mat w x 100

[0198] Volatile solids content (wet vs. wet) (%) = [(mat d - mat wnv ) / mat w ] x 100

[0199] Volatile solids content (on dry basis) (%) = [(mat d - mat wnv ) / mat d ] x 100

[0200] Biodegradability was tested for biodegradability by composting for 12 weeks in a reactor (25±2℃) that could maintain aerobic conditions according to “KS T ISO 20200: 2004 Plastics - Determination of plastic degradability under defined composting conditions by laboratory-scale testing.”

[0201] After the test was completed, the sample was filtered using standard mesh sizes of 10 mm, 5 mm and 2 mm, washed and dried at 40±2 ℃.

[0202]

[0203] In the filtration process, plastic materials caught in the net are considered non-degradable, while those passing through the net are considered degraded. Biodegradability D was calculated using the following mathematical formula. The results are shown in Table 5.

[0204] [Equation 2]

[0205] Biodegradability D(%)=[(m i - m f ) / m i ] x 100

[0206] In the above formula, m i is the initial dry solid mass of the sample (g),

[0207] m f is the dry solid mass (g) of the sieved residual sample (undecomposed matter).

[0208]

[0209] In addition, when conducting a biodegradability evaluation experiment on the films manufactured in Example 1 and Comparative Examples 1 and 2, the decomposition degree of the films was observed before the experiment and 12 weeks after the experiment, and the results are shown in Figures 1a to 3b.

[0210]

[0211] m i (g)m f (g) Biodegradability (%) Example 15.04 g2.52 g49.9 Comparative Example 15.04 g2.94 g41.6 Comparative Example 25.03 g3.87 g23.3

[0212] A test is considered valid if the reduction in total volatile-solid content between the initial synthetic waste and the compost obtained at the end of the test in each reactor is at least 30%, and the difference in biodegradability is less than 10% when the test is repeated three times. Considering this, the film manufactured with the resin composition of the example exhibited a biodegradability of 49.9%, confirming that the resin composition of the example has excellent biodegradability.

[0213]

[0214] Experimental Example 4

[0215] Enzyme screening using the immersion method was performed on the films of the examples and comparative examples manufactured in the above experimental example 1, and biodegradability was evaluated from the results.

[0216] (1) Preparation of specimens

[0217] In detail, the 0.05 mm thick films of Examples 1 and 2 and Comparative Examples 1 and 2 manufactured in Experimental Example 1 were cut into a size of 1 cm x 1 cm (width x length) to manufacture specimens, and sterilized with ethanol.

[0218]

[0219] (2) Preparation of hydrolytic enzyme solution

[0220] A hydrolytic enzyme solution was prepared by mixing the following two types of lipase, two types of cutinase, and one type of alpha amylase in 1 ml of 1X Phosphate-Buffered Saline (PBS).

[0221] LipaseRhizopus Oryzae1000 units

[0222] LipasePseudomonas Cepacia3000 units

[0223] CutinaseAspergillus Oryzae2000 units

[0224] CutinaseHumicola Insolens1500 units

[0225] α-amylaseBacillus Licheniformis1500 units

[0226]

[0227] (3) Biodegradability evaluation

[0228] Biodegradability evaluation was performed under the conditions of 37 ℃ and 760 mmHg using the following method.

[0229] 0.5 ml of the hydrolytic enzyme solution of (2) was added to one well of a 24-well plate, and two specimens of (1) were immersed for 7 days. Immediately after immersion (day 0), 5 days after immersion (day 5), and 7 days after immersion (day 7), the specimens were visually observed for disintegration and falling off of pieces. The results are shown in Fig. 4.

[0230]

[0231] As a result of the experiment, the films of Examples 1 and 2 were biodegraded faster than those of Comparative Example 2. Considering that Comparative Example 2 is a product certified for home composting, it can be expected that the film manufactured using the resin composition according to the present invention will also exhibit high biodegradability under home and soil composting conditions.

[0232]

[0233] Experimental Example 5

[0234] Enzyme screening using a spray method was performed on the films of the examples and comparative examples manufactured in the above experimental example 1, and biodegradability was evaluated from the results.

[0235]

[0236] (1) Manufacturing of badges

[0237] A circular 1% agar plate with a diameter of 90 mm was prepared using a method for preparing a petri dish medium.

[0238] A solution was prepared by adding 10 g of agar (manufacturer: BD Difco, product name: Bacto Agar, product number: 214010) and 1000 ml of distilled water to a 2000 ml Erlenmeyer flask. The solution was placed in an autoclave and sterilized at 121°C and 0.1 MPa for 15 minutes. 10 ml of the sterilized solution was dispensed into sterile round petri dishes with a diameter of 90 mm to prepare a medium.

[0239]

[0240] (2) Preparation of resin solution

[0241] The films of Examples 3 to 6 and Comparative Examples 3 and 4 manufactured in Experimental Example 1 above were each dissolved in 20 ml of chloroform at 1 wt% to prepare a resin solution.

[0242]

[0243] (3) Preparation of hydrolytic enzyme solution

[0244] A hydrolytic enzyme solution (stock solution) was prepared by mixing the following two types of lipase and two types of cutinase in 1 ml of 1X Phosphate-Buffered Saline (PBS). In addition, a 1 / 10 dilution of the stock solution was prepared.

[0245] LipaseRhizopus Oryzae1000 units

[0246] LipasePseudomonas Cepacia3000 units

[0247] CutinaseAspergillus Oryzae2000 units

[0248] CutinaseHumicola Insolens1500 units

[0249]

[0250] (4) Biodegradability evaluation

[0251] 6 ml of the resin solution prepared in (2) was evenly sprayed on the agar medium of (1) above and dried at room temperature (25°C) for about 10 minutes to allow the solvent to evaporate, thereby preparing a specimen with an average thickness of 0.7 μm. The average thickness of the specimen was measured using an optical profiler (model name: NewView TM The roughness of the specimen before and after spraying was measured using a 8300, Zygo corp., and the result was obtained from this.

[0252] Next, 5 μl of the original solution and 1 / 10 dilution of the hydrolytic enzyme solution (3) were each dropped onto four points on each of the above specimens. The area and clarity of the clear zones created by the hydrolytic enzyme solution decomposing the resin sprayed onto the medium were visually observed over time. The experimental results are shown in Figure 5.

[0253] Meanwhile, the entire process of the biodegradability evaluation was performed at 28°C and atmospheric pressure (760±20 torr).

[0254]

[0255] As a result of the experiment, a clear zone began to form in Example 6 and Comparative Example 4 1 hour after enzyme treatment, a clear zone began to form in Examples 4 and 5 1.5 hours after enzyme treatment, a clear zone began to form in Example 3 2.5 hours after enzyme treatment, and a clear zone began to form in Comparative Example 3 8 hours after enzyme treatment.

Claims

1. Polybutylene adipate-co-terephthalate, mesopolylactic acid, and Containing maleic anhydride-graft-polyolefin elastomers, Comprising the above polybutylene adipate-co-terephthalate and meso polylactic acid in a weight ratio of 9.0:1.0 to 6.0:4.0, Resin composition.

2. In paragraph 1, A resin composition wherein the meso polylactic acid is an amorphous polymer having a repeating structure represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, n is an integer greater than or equal to 2.

3. In paragraph 1, The above meso polylactic acid is a resin composition satisfying the conditions (a1) and (a2) below: (a1) Density (ISO 1183): 1.15 to 1.35 g / ml (a2) Melt flow index (MFI) (ISO 1133-11, 190℃, 2.16kg): 3 to 15 g / 10min.

4. In paragraph 1, The above polybutylene adipate-co-terephthalate is a resin composition satisfying the conditions of (b1) and (b2) below: (b1) Melting temperature: 100 to 140 ℃ (b2) Melting index (MI) (ASTM D 1238, 190℃, 2.16kg): 2.0 to 5.5 g / 10min.

5. In paragraph 1, A resin composition, wherein the maleic anhydride-graft-polyolefin elastomer is included in an amount of 0.1 to 1.5 parts by weight based on 100 parts by weight of the total combined weight of the polybutylene adipate-co-terephthalate and meso polylactic acid.

6. In paragraph 1, A resin composition wherein the maleic anhydride-graft-polyolefin elastomer has a weight average molecular weight of 100,000 g / mol to 130,000 g / mol.

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

8. In paragraph 7, Tensile strength in MD direction measured according to ISO 527 standard is 300 kgf / cm 2 Ideal, biodegradable resin molded product.

9. In paragraph 7, A biodegradable resin molded product having an elongation value in the MD direction of 500% or more as measured according to ISO 527 standards.

10. In paragraph 7, Tensile modulus in MD direction measured according to ISO 527 standard is 1600 kgf / cm 2 Ideal, biodegradable resin molded product.

11. In paragraph 7, A biodegradable resin molded product having a hydrolysis viscosity reduction rate of 70% or more calculated according to the following mathematical formula 1 after exposure to distilled water at 50 to 60°C for 192 hours. [Mathematical Formula 1] Hydrolysis viscosity reduction rate (%) = [(Vo-Vf) / Vo] x 100 In the above equation, Vo is the zero shear viscosity of the molded product before the hydrolysis experiment, Vf is the zero shear viscosity of the molded product after a hydrolysis test in which the product is exposed to distilled water at 50 to 60°C for 192 hours.

12. In paragraph 7, A biodegradable resin molded product having a biodegradability of 45% or more as measured according to the standard biodegradation test standard ISO 14855.

13. In paragraph 7, Biodegradable film, biodegradable resin molded product.

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