Biodegradable resin composition and biodegradable article containing same

Abstract

The present invention relates to a biodegradable resin composition and a biodegradable article comprising the same. Specifically, according to one embodiment of the present invention, the biodegradable resin composition comprises a PLA resin, a PHA resin, and a lubricant, where the PHA resin is an amorphous PHA resin. By controlling the weight ratio of the PLA resin to the PHA resin and the amount of the lubricant, a biodegradable resin composition with excellent biodegradability and biocompatibility and environmental friendliness can be obtained. Since mechanical properties such as elongation and tensile strength suitable for molding and processing can be ensured, the composition may have excellent moldability and processability, and in particular, may have remarkably excellent Izod impact strength. Therefore, biodegradable articles prepared using the above biodegradable resin composition can have excellent quality during storage and distribution of products using the biodegradable article.

Description

[Technical Field]

[0001] The present disclosure relates to a biodegradable resin composition and a biodegradable article comprising the same. [Background technology]

[0002] In recent years, amid growing concern about environmental issues, active research has been conducted into the treatment and recycling of various household wastes. Specifically, polymeric materials, which are inexpensive and easy to process, are widely used in the manufacture of various products such as paper, film, textiles, packaging materials, bottles, and containers. However, when these products reach the end of their lifespan, incineration can release harmful substances, and complete natural decomposition can take hundreds of years, depending on the type.

[0003] Therefore, research is ongoing into biodegradable polymers that can decompose in a short period of time, making them environmentally friendly, while also improving mechanical properties such as flexibility and strength, productivity, and processability, thereby extending the life of the product itself, reducing waste, and increasing recyclability.

[0004] Polyhydroxyalkanoates (PHAs) are biodegradable polymers composed of several hydroxylcarboxylic acids that are produced by many microorganisms and used as intracellular storage materials. Polyhydroxyalkanoates have similar physical properties to conventional petroleum-derived synthetic polymers such as polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), and polybutylene succinate adipate (PBSA), and are completely biodegradable and highly biocompatible.

[0005] On the other hand, polylactic acid (PLA) is a thermoplastic polymer obtained by chemical synthesis from lactic acid produced by biological fermentation, and has excellent biocompatibility and biodegradability. Polylactic acid (PLA) is widely used as a raw material for disposable packaging containers, paints, films or sheets, and fibers. However, because polylactic acid resin is a semi-crystalline polymer, it is vulnerable to impact and easily breaks. Polylactic acid resin also has drawbacks such as low flexibility and heat resistance. Therefore, during molding processing to manufacture packaging containers using polylactic acid resin, defects such as breakage and cracks may occur, which may damage the contents during storage and distribution. Therefore, there is a need for the development of a biodegradable resin composition that is environmentally friendly due to its excellent biodegradability and biocompatibility, can be easily applied in various fields, and has mechanical properties suitable for molding processing, such as elongation, and impact strength.

[0006] As an example, Korean Patent Publication No. 2012-0103158 discloses a composition that is excellent in biodegradability and durability, which is obtained by adjusting the weight ratio of starch, at least one selected from the group consisting of polylactic acid (PLA), polycaprolactone (PCL), polyhydroxybutyrate-co-valerate (PHBV), polyvinyl alcohol (PVA), polybutylene succinate (PBS), and polyglycolic acid (PG), to polypropylene carbonate (PPC). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent Publication No. 2012-0103158 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present disclosure is to provide a biodegradable resin composition that has excellent biodegradability and biocompatibility, and is environmentally friendly, while being able to improve mechanical properties such as elongation and impact strength suitable for molding processing, and a biodegradable article containing the same. [Means for solving the problem]

[0009] A biodegradable resin composition according to one embodiment of the present disclosure comprises a polylactic acid (PLA) resin, a polyhydroxyalkanoate (PHA) resin, and a lubricant, wherein the PHA resin is an amorphous PHA resin, the weight ratio of the PLA resin to the PHA resin is 95:5 to 55:45, and the lubricant is used in an amount of 0.1 phr to 5 phr.

[0010] According to one embodiment of the present disclosure, the PHA resin may contain 4-hydroxybutyric acid (4-HB) repeat units in an amount of 25% to 60% by weight.

[0011] According to one embodiment of the present disclosure, the PHA resin may further comprise at least one repeat unit selected from the group consisting of 3-hydroxybutyric acid (3-HB), 3-hydroxypropionic acid (3-HP), 3-hydroxyhexanoate (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

[0012] According to one embodiment of the present disclosure, the PHA resin may have a weight average molecular weight of 10,000 g / mol to 1,200,000 g / mol, a glass transition temperature (Tg) of −45° C. to −10° C. as measured by differential scanning calorimetry (DSC), and a melt flow index (MFI) of 0.1 g / 10 min to 20 g / 10 min as measured at 165° C. under a 5 kg load according to ASTM D1238.

[0013] According to one embodiment of the present disclosure, the lubricant may contain at least one selected from the group consisting of a fatty acid or a salt thereof, a wax, and an amide-based compound.

[0014] According to one embodiment of the present disclosure, the biodegradable resin composition may contain at least one additive selected from the group consisting of a plasticizer, a nucleating agent, and an antioxidant.

[0015] According to one embodiment of the present disclosure, the biodegradable resin composition may contain a plasticizer in an amount of 0 phr to 10 phr, a nucleating agent in an amount of 0 phr to 30 phr, and an antioxidant in an amount of 0 phr to 10 phr.

[0016] According to one embodiment of the present disclosure, the biodegradable resin composition has a tensile strength of 20 MPa to 90 MPa according to ASTM D638, an elongation of 9% or more according to ASTM D638, and an Izod impact strength (without notch) of 20 kJ / m when measured at room temperature according to ASTM D256. 2 It may be more than that.

[0017] A biodegradable article according to another embodiment of the present disclosure includes a biodegradable resin composition.

[0018] According to another embodiment of the present disclosure, the biodegradable article may be a sheet, a container, a tray, or a blister package.

[0019] A method for preparing a biodegradable article according to another embodiment of the present disclosure includes mixing a polylactic acid (PLA) resin, a polyhydroxyalkanoate (PHA) resin, and a lubricant to prepare a biodegradable resin composition, and molding the biodegradable resin composition.

[0020] According to another embodiment of the present disclosure, the molding step may be performed by at least one method selected from the group consisting of extrusion molding, injection molding, blow molding, and thermoforming.

[0021] According to another embodiment of the present disclosure, the molding step may be carried out at a temperature between 80°C and 220°C. [Effects of the Invention]

[0022] A biodegradable resin composition according to one embodiment of the present disclosure comprises a PLA resin, a PHA resin, and a lubricant, and the weight ratio of the PLA resin to the PHA resin and the content of the lubricant are adjusted. As a result, the biodegradable resin composition is environmentally friendly due to its excellent biodegradability and biocompatibility, and can ensure mechanical properties such as elongation and tensile strength suitable for molding and processing, resulting in excellent moldability and processability.

[0023] In particular, the use of amorphous PHA resins can further improve mechanical properties such as elongation and tensile strength, which are suitable for molding processes. Adjusting the type and content of the lubricant used in combination with these can maximize the improvement in Izod impact strength at room temperature or -20°C.

[0024] In addition, the biodegradable resin composition and the biodegradable article containing the same have excellent thermal and mechanical properties and are biodegradable in both soil and the ocean, so they can be advantageously applied to a wider variety of fields and exhibit excellent properties. In particular, the biodegradable article produced using the biodegradable resin composition has excellent quality during product storage and distribution. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present disclosure will be described in detail below. The present disclosure is not limited to the disclosure described below, and can be modified in various forms without departing from the spirit of the present invention.

[0026] In this specification, when a part is described as "comprising" an element, it does not mean that the part excludes other elements, but that the part may include other elements, unless otherwise specified.

[0027] Unless otherwise specified, the numerical values ​​and expressions relating to the amounts of components, reaction conditions, etc. used herein can be understood even if modified by the term "approximately."

[0028] In this specification, terms such as first, second, etc. are used in describing various components. However, these components should not be bound by these terms. These terms are used simply to distinguish one component from another.

[0029] Biodegradable resin composition A biodegradable resin composition according to one embodiment of the present disclosure comprises a polylactic acid (PLA) resin, a polyhydroxyalkanoate (PHA) resin, and a lubricant, wherein the PHA resin is an amorphous PHA resin, the weight ratio of the PLA resin to the PHA resin is 95:5 to 55:45, and the lubricant is used in an amount of 0.1 phr to 5 phr.

[0030] A biodegradable resin composition according to one embodiment of the present disclosure includes a polyhydroxyalkanoate (PHA) resin.

[0031] PHA is a natural thermoplastic polyester polymer that accumulates within microbial cells. Because it is a biodegradable material, it can be composted and ultimately decomposes into carbon dioxide, water, and organic waste without producing hazardous waste. In particular, PHA is biodegradable in soil and the ocean, so biodegradable resin compositions and biodegradable articles prepared therewith may have environmentally friendly properties when they contain PHA resin. Thus, the biodegradable resin compositions and biodegradable articles prepared therewith have the significant advantage of being biodegradable and environmentally friendly, making them applicable in a variety of fields.

[0032] Specifically, PHA is a natural thermoplastic polyester polymer that accumulates within microbial cells. PHA is formed when a bacterium is unevenly supplied with nutrients (nitrogen sources, phosphorus, etc.), causing it to accumulate PHA within the cell and store carbon and energy.

[0033] Furthermore, PHA has similar physical properties to conventional petroleum-derived synthetic polymers such as polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), and polybutylene succinate adipate (PBSA), and is completely biodegradable and has excellent biocompatibility.

[0034] In particular, unlike other environmentally friendly plastic materials such as PBS, PLA, and PTT, PHA can be synthesized from over 150 types of monomers, and depending on the type of monomer, hundreds of different types of PHA can be prepared. Depending on the type of monomer, there are hundreds of different types of PHA, each with completely different structures and properties.

[0035] According to one embodiment of the present disclosure, the PHA resin may be an amorphous PHA resin having no crystallinity. By using an amorphous PHA resin having no crystallinity as the PHA resin, it is possible to further improve mechanical properties such as elongation and tensile strength suitable for molding processability.

[0036] The PHA resin may contain 4-hydroxybutyric acid (4-HB) repeating units, specifically, the PHA resin may be a copolymer PHA resin containing 4-HB repeating units.

[0037] In general, examples of repeating units that a PHA resin may have include 2-hydroxybutyrate, lactic acid, glycolic acid, 3-hydroxybutyric acid (hereinafter referred to as 3-HB), 3-hydroxypropionic acid (hereinafter referred to as 3-HP), 3-hydroxyvalerate (hereinafter referred to as 3-HV), 3-hydroxyhexanoate (hereinafter referred to as 3-HH), 3-hydroxyheptanoate (hereinafter referred to as 3-HHep), 3-hydroxyoctanoate (hereinafter referred to as 3-HV), and the like. Examples of repeating units include 3-hydroxybutyrate (3-HB), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH). The PHA resin may contain one or more repeating units selected from the above.

[0038] According to one embodiment of the present disclosure, the PHA resin may further comprise at least one repeat unit selected from the group consisting of 3-hydroxybutyric acid (3-HB), 3-hydroxypropionic acid (3-HP), 3-hydroxyhexanoate (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

[0039] Specifically, the PHA resin may further contain one or more repeating units selected from the group consisting of 3-HB, 4-HB, 3-HP, 3-HH, 3-HV, 4-HV, 5-HV, and 6-HH. More specifically, the PHA resin may contain 4-hydroxybutyric acid (4-HB) repeating units, and may further contain one or more repeating units selected from the group consisting of 3-HB, 3-HP, 3-HH, 3-HV, 4-HV, 5-HV, and 6-HH.

[0040] The PHA resin may be a copolymer PHA resin containing 4-HB repeating units and further containing one type of repeating unit different from the 4-HB repeating units, or a copolymer PHA resin containing two, three, four, five, six or more different types of repeating units. For example, the PHA resin may be poly-3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter also referred to as 3HB-co-4HB) containing 4-HB repeating units and 3-HB repeating units.

[0041] For example, the PHA resin may contain 4-HB repeating units in an amount of 25% to 60% by weight, 26% to 55% by weight, 28% to 52% by weight, 29% to 45% by weight, 30% to 42% by weight, or 31% to 40% by weight. By ensuring that the content of 4-HB repeating units falls within the above range, the desired crystallinity can be ensured. By including a PHA resin containing 4-HB repeating units in an amount within the above range together with a PLA resin, the biodegradable resin composition of the present disclosure is environmentally friendly due to its excellent biodegradability and biocompatibility, and also ensures mechanical properties such as elongation and impact strength suitable for molding.

[0042] The PHA resin may also contain 20% or more by weight of 3-HB repeat units. For example, the PHA resin may contain 3-HB repeat units in an amount of 35% or more, 40% or more, 50% or more, 60% or more, 70% or more, or 75% or more and 99% or less, 98% or less, 97% or less, 96% or less, 95% or less, 93% or less, 91% or less, 90% or less, 80% or less, 70% or less, 60% or less, or 55% or less by weight.

[0043] Furthermore, the PHA resin may contain isomers. For example, the PHA resin may contain structural isomers, enantiomers, or geometric isomers. Specifically, the PHA resin may contain structural isomers.

[0044] The crystallinity and amorphousness of the PHA resin may be adjusted by increasing the disorder in its molecular structure, specifically by adjusting the type or proportion of monomers or the type or content of isomers.

[0045] According to one embodiment of the present disclosure, the PHA resin may be an amorphous PHA (aPHA) resin. By using an amorphous PHA resin (aPHA resin) together with polylactic acid as the PHA resin, it is possible to compensate for the low impact strength and flexibility properties and ensure mechanical properties such as elongation and impact strength suitable for molding processing.

[0046] The weight-average molecular weight of the PHA resin may be 10,000 g / mol to 1,200,000 g / mol. For example, the weight-average molecular weight of the aPHA resin may be 10,000 g / mol to 1,000,000 g / mol, 50,000 g / mol to 1,000,000 g / mol, 200,000 g / mol to 1,200,000 g / mol, 250,000 g / mol to 1,000,000 g / mol, 100,000 g / mol to 900,000 g / mol, 500,000 g / mol to 900,000 g / mol, 200,000 g / mol to 800,000 g / mol, or 200,000 g / mol to 500,000 g / mol.

[0047] The PHA resin may have a glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) of −45° C. to −10° C. For example, the glass transition temperature (Tg) of aPHA may be −35° C. to −15° C., −35° C. to −20° C., or −30° C. to −20° C.

[0048] In addition, there are cases where the crystallization temperature (Tc) and melting temperature (Tm) of the aPHA resin cannot be measured.

[0049] In this specification, the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) can be measured using a differential scanning calorimeter (DSC). Specifically, the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) can be measured by performing the first or second scan in the differential scanning calorimetry (DSC) mode, and can be confirmed from the heat flow curve obtained by these scans. More specifically, the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) can be confirmed from the heat flow curve obtained when the temperature is increased from 40°C to 180°C at a rate of 10°C / min and then cooled to -50°C at a rate of 10°C / min.

[0050] The PHA resin may have a melt flow index (MFI) of 0.1 g / 10 min to 20 g / 10 min at 165° C. and 5 kg, measured in accordance with ASTM D1238. For example, the melt flow index of the aPHA resin measured in accordance with ASTM D1238 at 165°C and 5 kg may be 0.1g / 10 minutes to 15g / 10 minutes, 0.1g / 10 minutes to 12g / 10 minutes, 0.1g / 10 minutes to 10g / 10 minutes, 0.1g / 10 minutes to 8g / 10 minutes, 0.1g / 10 minutes to 6g / 10 minutes, 0.1g / 10 minutes to 5.5g / 10 minutes, 0.5g / 10 minutes to 10g / 10 minutes, 1g / 10 minutes to 10g / 10 minutes, 2g / 10 minutes to 8g / 10 minutes, 3g / 10 minutes to 6g / 10 minutes, or 3g / 10 minutes to 5.5g / 10 minutes.

[0051] The aPHA resin is distinguished from other PHA resins by the content of 4-HB repeating units, and may have at least one characteristic selected from the group consisting of glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and melt flow index.

[0052] According to one embodiment of the present disclosure, the weight ratio of PLA resin to PHA resin can be 95:5 to 55:45. For example, the weight ratio of PLA resin to PHA resin may be 90:10 to 55:45, 85:15 to 55:45, 80:20 to 55:45, 80:20 to 60:40, or 80:20 to 70:30. When the weight ratio of PLA to PHA satisfies the above range, mechanical properties such as elongation and impact strength suitable for molding can be ensured, and moldability and processability can be improved.

[0053] Specifically, the PLA resin may be used in an amount of more than 50% by weight, based on the total weight of the biodegradable resin composition. For example, the content of the PLA resin may be 52% by weight or more, 53% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, or 80% by weight or more, based on the total weight of the biodegradable resin composition.

[0054] The PHA resin may be used in an amount of less than 50% by weight, based on the total weight of the biodegradable resin composition. For example, the PHA resin content may be 49% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, or 30% by weight or less, based on the total weight of the biodegradable resin composition.

[0055] According to one embodiment of the present disclosure, the biodegradable resin composition includes a lubricant.

[0056] The lubricant may be used to prevent adhesion of the biodegradable resin composition to a cooling roll that occurs during extrusion processing, particularly in the process of producing a sheet for thermoforming.

[0057] Specifically, the lubricant may contain at least one selected from the group consisting of fatty acids or their salts, waxes, and amide compounds. For example, the lubricant may contain at least one selected from the group consisting of stearic acid and its monomers, oleic acid and its monomers, palmitic acid and its monomers, silicone, fatty acid alcohols, oleamide, erucamide, stearamide, calcium stearate, zinc stearate, magnesium stearate, aluminum stearate, potassium oleate, zinc oleate, magnesium oleate, aluminum oleate, calcium palmitate, zinc palmitate, magnesium palmitate, aluminum palmitate, ethylene bis(stearamide) (EBS), beeswax, carnauba wax, and candelilla wax.

[0058] The biodegradable resin composition contains the lubricant in an amount of 0.1 to 5 phr. For example, the lubricant content may be 0.1 to 3 phr, 0.2 to 2.5 phr, 0.3 to 1.5 phr, or 0.5 to 1.2 phr.

[0059] According to one embodiment of the present disclosure, the biodegradable resin composition may further contain at least one additive selected from the group consisting of a plasticizer, a nucleating agent, and an antioxidant.

[0060] The biodegradable resin composition may contain a plasticizer in an amount of 0 phr to 10 phr, a nucleating agent in an amount of 0 phr to 30 phr, and an antioxidant in an amount of 0 phr to 10 phr.

[0061] The plasticizer is used to enhance the flexibility and elasticity of the polylactic acid resin. The plasticizer may contain at least one selected from the group consisting of polyol-based plasticizers and citrate ester-based plasticizers. Examples of polyol-based plasticizers include ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, and pentaerythritol. Examples of citrate ester-based plasticizers include, but are not limited to, triethyl citrate (TEC), acetyltriethyl citrate (ATEC), tributyl citrate (TBC), acetyltributyl citrate (ATBC), and acetyltris(2-ethylhexyl) citrate (ATEHC).

[0062] The biodegradable resin composition may contain a plasticizer in an amount of 0 phr to 10 phr. For example, the content of the plasticizer may be 0.1 phr to 8 phr, 0.5 phr to 6 phr, 0.8 phr to 4 phr, 1 phr to 3.5 phr, 1.5 phr to 3.2 phr, or 2 phr to 3 phr.

[0063] The nucleating agent may be one that more effectively controls the crystallinity of the biodegradable resin composition. In the preparation process using the nucleating agent, processability such as processing speed can be further improved. For example, the nucleating agent may contain carbonate, silicate, etc. Examples of nucleating agents include, but are not limited to, calcium carbonate, silica, talc, boron nitride, and sorbitol derivatives.

[0064] The biodegradable resin composition may contain a nucleating agent in an amount of 0 phr to 30 phr. For example, the content of the nucleating agent may be 3 phr to 28 phr, 5 phr to 25 phr, 8 phr to 20 phr, 10 phr to 20 phr, 3 phr to 15 phr, or 5 phr to 10 phr.

[0065] The antioxidant is an additive for preventing decomposition by ozone or oxygen, preventing oxidation during storage, or preventing deterioration of physical properties. Conventional antioxidants may be used as long as they do not impair the effects of the present disclosure.

[0066] Specifically, the antioxidant may include at least one selected from the group consisting of hindered phenol-based antioxidants and phosphite-based (phosphorus-based) antioxidants.

[0067] The hindered phenol-based antioxidant may include, for example, at least one selected from the group consisting of 4,4'-methylenebis(2,6-di-t-butylphenol), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), and 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0068] The phosphite (phosphorus) antioxidant may include at least one selected from the group consisting of, for example, tris-(2,4-di-t-butylphenyl)phosphite, bis-(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis-(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, distearyl-pentaerythritol diphosphite, [bis(2,4-di-t-butyl-5-methylphenoxy)phosphino]biphenyl, and N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxyphosphepin-6-yl]oxy]-ethyl]ethanamine.

[0069] The biodegradable resin composition may contain the antioxidant in an amount of 0 phr to 10 phr. For example, the content of the antioxidant may be 0.1 phr to 3 phr, 0.2 phr to 2.5 phr, 0.3 phr to 1.5 phr, or 0.5 phr to 1.2 phr.

[0070] The biodegradable resin composition may have a tensile strength according to ASTM D638 of 20 MPa to 90 MPa, 20 MPa to 85 MPa, 30 MPa to 80 MPa, or 40 MPa to 70 MPa.

[0071] The biodegradable resin composition may have an elongation of 9% or more, 10% or more, 11% or more, 13% or more, 14% or more, or 15% or more.

[0072] The biodegradable resin composition has an Izod impact strength (without notch) of 20 kJ / m when measured at room temperature in accordance with ASTM D256. 2 More than 25kJ / m 2 More than 30kJ / m 2 More than 35kJ / m 2 or more than 40kJ / m 2 That's all.

[0073] When the Izod impact strength of the biodegradable resin composition satisfies the above range, the composition is suitable for molding and is less susceptible to defects such as breakage and cracking. Generally, the Izod impact strength is lower at -20°C than at room temperature, so by employing a biodegradable resin composition according to one embodiment of the present disclosure, the impact strength at room temperature or -20°C can be improved. Thus, when a product is stored and distributed using a biodegradable article manufactured using the biodegradable resin composition, the product is less likely to be damaged, resulting in excellent quality.

[0074] biodegradable articles A biodegradable article according to another embodiment of the present disclosure includes a biodegradable resin composition.

[0075] Details of the biodegradable resin composition are as described above.

[0076] According to another embodiment of the present disclosure, the biodegradable article may be a sheet, a container, a tray, or a blister package.

[0077] Biodegradable articles manufactured from the biodegradable resin composition are environmentally friendly due to their excellent biodegradability and biocompatibility, and have excellent moldability and processability due to the mechanical properties such as elongation and tensile strength suitable for molding. In particular, they have excellent Izod impact strength. Therefore, when biodegradable articles manufactured using the above biodegradable resin composition are stored and distributed, the products are less likely to be damaged, resulting in excellent quality.

[0078] Method for preparing biodegradable articles A method for preparing a biodegradable article according to another embodiment of the present disclosure includes mixing a polylactic acid (PLA) resin, a polyhydroxyalkanoate (PHA) resin, and a lubricant to prepare a biodegradable resin composition, and molding the biodegradable resin composition, wherein the PHA resin is an amorphous PHA resin, the weight ratio of the PLA resin to the PHA resin is 95:5 to 55:45, and the lubricant is used in an amount of 0.1 phr to 5 phr.

[0079] Details of the biodegradable resin composition are as described above.

[0080] The molding step is a step of molding the biodegradable resin composition into a biodegradable article, and may be performed by at least one method selected from the group consisting of extrusion molding, injection molding, blow molding, and thermoforming.

[0081] The blow molding may be at least one selected from the group consisting of extrusion blow molding, injection blow molding, and injection stretch blow molding.

[0082] For example, when the biodegradable article is a sheet-like article, it can be produced by sheet extrusion.

[0083] When the biodegradable article is in the form of a tray, blister package, etc., it can be manufactured by sheet extrusion and thermoforming.

[0084] Furthermore, when the biodegradable article is a container-shaped article, it can be manufactured by injection molding and blow molding. Alternatively, when the biodegradable article is a container-shaped article, it can be manufactured by injection molding, blow molding, and thermoforming. Furthermore, when the biodegradable article is a container-shaped article, it can also be manufactured by injection stretch blow molding, but is not limited to this.

[0085] The molding step may be carried out at 80°C to 220°C, 80°C to 200°C, 80°C to 150°C, 80°C to 100°C, 150°C to 220°C, 152°C to 210°C, 155°C to 200°C, 160°C to 210°C, or 175°C to 200°C.

[0086] According to another embodiment of the present disclosure, a biodegradable article can be produced by extrusion molding and thermoforming the biodegradable resin composition.

[0087] For example, the above biodegradable resin composition may be extruded at 155°C to 200°C, 155°C to 195°C, or 160°C to 185°C to produce a thermoforming sheet, and this thermoforming sheet may be thermoformed using a mold at 70°C to 120°C, 75°C to 110°C, or 80°C to 100°C to produce a biodegradable article in the shape of a tray, blister package, or the like.

[0088] According to another embodiment of the present disclosure, a biodegradable article can be produced by injection stretch blow molding the biodegradable resin composition.

[0089] For example, the biodegradable resin composition may be injection molded at 155°C to 220°C, 165°C to 210°C, or 175°C to 200°C to produce a preform, and the preform may then be heat-treated and blow-molded at 70°C to 120°C, 75°C to 110°C, or 80°C to 100°C to produce a biodegradable article in the shape of a container or the like.

[0090] Mode of Invention The present disclosure will be described in more detail below with reference to examples. However, the following examples are for the purpose of illustrating the present disclosure and are not intended to limit the scope of the present disclosure to these examples alone. [Example]

[0091] Preparation of biodegradable resin composition (1) Example 1-1 A biodegradable resin composition was prepared by mixing polylactic acid resin (PLA, manufactured by NatureWorks) and polyhydroxyalkanoate (aPHA, 4-hydroxybutyric acid (4-HB) content: 33% by weight, weight average molecular weight (Mw): 600,000 g / mol, melt flow index at 165°C and 5 kg according to ASTM D1238: 5.5 g / 10 min) in an 80:20 weight ratio, and adding 0.5 phr of a fatty acid lubricant. Here, phr (per hundred resin) refers to the unit of the amount of material added per 100 parts by weight of polymer (1 phr: 1 g added per 100 g of polymer).

[0092] Examples 1-2, 1-3 and Comparative Example 1-1 Biodegradable resin compositions were prepared in the same manner as in Example 1-1, except that the components and their contents were changed as shown in Table 1 below.

[0093] Test Example 1-1: Tensile strength and elongation The tensile strength (MPa) and elongation (%) of each of the biodegradable resin compositions prepared in Examples 1-1 to 1-3 and Comparative Example 1-1 were measured in accordance with ASTM D638.

[0094] [Table 1]

[0095] As shown in Table 1 above, the tensile strength and elongation of each of the biodegradable resin compositions of Examples 1-1 to 1-3 are within the desired ranges.

[0096] Preparation of biodegradable resin composition (2) Example 2-1 A biodegradable resin composition was prepared by mixing polylactic acid resin (PLA, manufactured by NatureWorks) and polyhydroxyalkanoate (aPHA, 4-hydroxybutyric acid (4-HB) content: 33 wt%, weight average molecular weight (Mw): 600,000 g / mol, melt flow index at 165°C and 5 kg according to ASTM D1238: 5.5 g / 10 min) in a weight ratio of 75:25, and adding 1.0 phr of a wax-based lubricant, 2.5 phr of a citrate ester-based plasticizer, 5 phr of a silicate-based nucleating agent, and 1.0 phr of a hindered phenol-based antioxidant.

[0097] Example 2-2 A biodegradable resin composition was prepared by mixing polylactic acid resin (PLA, manufactured by NatureWorks) and polyhydroxyalkanoate (aPHA, 4-hydroxybutyric acid (4-HB) content: 33 wt%, weight average molecular weight (Mw): 600,000 g / mol, melt flow index at 165°C and 5 kg according to ASTM D1238: 5.5 g / 10 min) in a weight ratio of 75:25, to which was further added 0.3 phr of an amide-based lubricant and 1.0 phr of a hindered phenol-based antioxidant.

[0098] Comparative Example 2-1 Biodegradable resin compositions were prepared in the same manner as in Example 2-1, except that the components and their contents were changed as shown in Table 2.

[0099] Test Example 2-1: Tensile strength and elongation The tensile strength (MPa) and elongation (%) of each of the biodegradable resin compositions prepared in Example 2-1, Example 2-2, and Comparative Example 2-1 were measured in accordance with ASTM D638.

[0100] Test Example 2-2: Izod impact strength The biodegradable resin compositions prepared in Examples 2-1, 2-2, and Comparative Example 2-1 were measured for Izod impact strength (no notch, kJ / m) at room temperature and -20°C in accordance with ASTM D256. 2 ) was measured.

[0101] Here, when the Izod impact strength of Example 2-1 was measured at room temperature, the test piece did not break due to its excellent impact strength properties, so it was designated NB (Non-Break). In addition, although the Izod impact strength is generally lower at -20°C compared to room temperature, the biodegradable resin composition prepared in Comparative Example 2-1 had an Izod impact strength of 2.7 kJ / m at room temperature. 2 and was not measured separately at -20°C.

[0102] [Table 2]

[0103] As shown in Table 2 above, the biodegradable resin compositions of Examples 2-1 and 2-2 both had tensile strength and elongation within the desired ranges, and in particular had very good Izod impact strength. In particular, the resin composition of Example 2-1 had excellent impact strength properties, with no breakage of test pieces at room temperature, and an Izod impact strength measured at a low temperature of -20°C of 45 kJ / m 2 Therefore, the biodegradable resin composition according to the present disclosure is highly suitable for molding and processing, and the product is not damaged not only at room temperature but also during distribution and storage in a frozen or refrigerated state, thereby improving the quality of articles manufactured using the composition.

[0104] Preparation of biodegradable articles Example 3-1 The biodegradable resin composition prepared in Example 1-1 was extruded at 155°C to 200°C to prepare a thermoformed sheet (thickness: 310 μm), which was then thermoformed using a mold at 80°C to 100°C to prepare a tray-shaped biodegradable article.

[0105] Example 3-2 A biodegradable article was prepared in the same manner as in Example 3-1, except that the biodegradable resin composition prepared in Example 1-2 was used instead of the biodegradable resin composition prepared in Example 1-1.

[0106] Example 3-3 The biodegradable resin composition prepared in Example 2-1 was injection molded at 175°C to 200°C to prepare a preform, which was then heat-treated at 80°C to 100°C and sprayed to prepare a container-shaped biodegradable article.

[0107] Comparative Example 3-1 A biodegradable article was prepared in the same manner as in Example 3-1, except that the biodegradable resin composition prepared in Comparative Example 1-1 was used instead of the biodegradable resin composition prepared in Example 1-1.

[0108] Test Example 3-1: Suitability for molding processing In the process of producing biodegradable articles using the biodegradable resin compositions prepared in Examples 3-1 to 3-3 and Comparative Example 3-1, the suitability for molding processing was evaluated.

[0109] Specifically, the evaluation was made by marking "x" when defects such as breakage or cracking occurred during the manufacturing process of the biodegradable article, and marking "o" when no defects occurred.

[0110] [Table 3]

[0111] As shown in Table 3 above, the biodegradable articles produced in Examples 3-1 to 3-3 had excellent moldability, and no defects such as breakage or cracking occurred during the manufacturing process of the biodegradable articles. Specifically, the biodegradable articles of Examples 3-1 and 3-2 manufactured by thermoforming and the biodegradable article of Example 3-3 manufactured by injection stretch blow molding had excellent moldability, and no breakage or cracking occurred during subsequent processes such as cutting and blowing after heating during the manufacturing process.

Claims

1. A biodegradable resin composition comprising a polylactic acid (PLA) resin, a polyhydroxyalkanoate (PHA) resin, and a lubricant, wherein the PHA resin is an amorphous PHA resin, the weight ratio of the PLA resin to the PHA resin is 95:5 to 55:45, and the lubricant is used in an amount of 0.1 phr to 5 phr.

2. 2. The biodegradable resin composition according to claim 1, wherein the PHA resin contains 4-hydroxybutyric acid (4-HB) repeating units in an amount of 25% to 60% by weight.

3. 2. The biodegradable resin composition according to claim 1, wherein the PHA resin further comprises at least one repeating unit selected from the group consisting of 3-hydroxybutyric acid (3-HB), 3-hydroxypropionic acid (3-HP), 3-hydroxyhexanoate (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

4. The biodegradable resin composition according to claim 1, wherein the PHA resin has a weight average molecular weight of 10,000 g / mol to 1,200,000 g / mol, a glass transition temperature (Tg) of −45° C. to −10° C. as measured by differential scanning calorimetry (DSC), and a melt flow index (MFI) of 0.1 g / 10 min to 20 g / 10 min as measured at 165° C. under a load of 5 kg in accordance with ASTM D1238.

5. The biodegradable resin composition according to claim 1, wherein the lubricant comprises at least one selected from the group consisting of a fatty acid or a salt thereof, a wax, and an amide-based compound.

6. The biodegradable resin composition according to claim 1, further comprising at least one additive selected from the group consisting of a plasticizer, a nucleating agent, and an antioxidant.

7. 7. The biodegradable resin composition according to claim 6, wherein the biodegradable resin composition comprises the plasticizer in an amount of 0 phr to 10 phr, the nucleating agent in an amount of 0 phr to 30 phr, and the antioxidant in an amount of 0 phr to 10 phr.

8. The biodegradable resin composition has a tensile strength of 20 MPa to 90 MPa according to ASTM D638, an elongation of 9% or more according to ASTM D638, and an Izod impact strength (without notch) of 20 kJ / m when measured at room temperature according to ASTM D256. ２ The biodegradable resin composition according to claim 1, wherein the biodegradable resin composition is a polymerizable compound.

9. A biodegradable article comprising the biodegradable resin composition according to claim 1.

10. The biodegradable article of claim 9 , wherein the biodegradable article is a sheet, a container, a tray, or a blister package.

11. A method for preparing a biodegradable article, comprising: mixing a polylactic acid (PLA) resin, a polyhydroxyalkanoate (PHA) resin, and a lubricant to prepare the biodegradable resin composition of claim 1; and molding the biodegradable resin composition.

12. The method for preparing a biodegradable article according to claim 11, wherein the molding step is carried out by at least one method selected from the group consisting of extrusion, injection molding, blow molding, and thermoforming.

13. The method for preparing a biodegradable article according to claim 11, wherein the molding step is carried out at a temperature of 80°C to 220°C.

Images