Composition for biodegradable film, biodegradable film comprising same, and method for manufacturing biodegradable film

Abstract

The composition for a biodegradable film according to one embodiment includes a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature in a specific range, whereby the composition satisfies a torque applied to a screw at a pressure of 46 bar or less in an extruder during extrusion molding of 70% or less, thus, it is possible to achieve improvements in processability and productivity, and to provide an environmentally friendly biodegradable film and biodegradable product having excellent biodegradability and mechanical properties.

Description

Technical Field

[0001] The embodiments relate to a composition for a biodegradable film, a biodegradable film comprising the same, and a method for preparing a biodegradable film. Background Art

[0002] Currently commercialized general plastics have excellent physical properties, and due to stable supply and price, the demand is increasing. However, problems with waste plastic disposal are constantly emerging in life. Since they do not decompose under natural conditions such as the ocean and soil, they are becoming a factor causing serious environmental pollution problems. To solve these environmental pollution problems, active research has been conducted on biodegradable plastics in recent years.

[0003] Biodegradable plastics refer to substances that are decomposed by microorganisms existing in nature into low molecular weight substances and ultimately decomposed into water and carbon dioxide, or water and methane gas. Examples of such biodegradable plastics may include biodegradable resins such as polylactic acid (PLA), poly(butylene adipate terephthalate) (PBAT), and poly(butylene succinate) (PBS).

[0004] The above biodegradable resins are particularly used for disposable packaging materials for food, disposable bags, laminates, etc. When applying these biodegradable resins to biodegradable films or biodegradable products, various additives are used to ensure functionality.

[0005] Generally, most commonly used additives are petroleum-based products. In most cases, they do not meet the purpose of developing environmentally friendly substances. Therefore, in order to pursue environmentally friendly products, various attempts are being made to develop biodegradable films and products using additives derived from natural sources.

[0006] However, there are limitations in providing high-quality biodegradable films and products that simultaneously satisfy environmentally friendly characteristics and mechanical properties such as strength and elongation by using additives derived from natural sources. From a process perspective, when using molding equipment, the applied load is large, and there are limitations in ensuring satisfactory processability and productivity in various processes such as extrusion molding.

[0007] [Prior Art Documents]

[0008] [Patent Documents]

[0009] (Patent Document 1) Korean Patent Publication No. 2012-0103158 Summary of the Invention

[0010] Technical Problem

[0011] The present disclosure is designed to solve the problems of the above prior art.

[0012] According to one embodiment, the present disclosure aims to provide a composition for a biodegradable film, which has excellent mechanical properties such as tensile strength and elongation at break, as well as improved processability and productivity during the molding process, and is biodegradable both in soil and in the ocean, and thus is environmentally friendly.

[0013] According to one embodiment, the present disclosure aims to provide a biodegradable film formed from the composition for a biodegradable film and a method for preparing the same.

[0014] Technical solutions

[0015] In one embodiment, to achieve the above object, there is provided a composition for a biodegradable film, which comprises a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature of 95°C to 250°C, wherein when the composition for a biodegradable film is fed into an extruder equipped with a screw at 6 rpm and extruded at a screw speed of 200 rpm at 170°C, the load (torque) applied to the screw is 70% or less at a pressure of 46 bar or less inside the extruder.

[0016] In the composition for a biodegradable film of another embodiment, the content of the plasticizer is 0.01 phr to 10 phr.

[0017] In the composition for a biodegradable film of another embodiment, the plasticizer is adipic acid.

[0018] In the composition for a biodegradable film of another embodiment, the polyhydroxyalkanoate (PHA) resin satisfies at least one of the following properties: a glass transition temperature (Tg) of -45°C to 80°C, a crystallization temperature (Tc) of 60°C to 120°C, and a melting temperature (Tm) of 100°C to 170°C.

[0019] In the composition for a biodegradable film of another embodiment, the polyhydroxyalkanoate (PHA) resin comprises at least one monomer selected from the group consisting of 4-hydroxybutyrate (4-HB), 3-hydroxybutyrate (3-HB), 3-hydroxypropionate (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

[0020] In a composition for a biodegradable film according to another embodiment, the polyhydroxyalkanoate (PHA) resin comprises a polyhydroxyalkanoate (PHA) copolymer (PHA copolymer) containing 4-hydroxybutyrate (4-HB) monomers, wherein the 4-hydroxybutyrate (4-HB) monomers are used in an amount of 1 mol% to 99 mol% based on the total number of moles of monomers contained in the polyhydroxyalkanoate (PHA) copolymer.

[0021] In a composition for a biodegradable film according to another embodiment, the polyhydroxyalkanoate (PHA) resin comprises a resin containing 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers, wherein the 4-hydroxybutyrate (4-HB) monomers are used in an amount of 1 mol% to 60 mol% based on the total number of moles of 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers.

[0022] In a composition for a biodegradable film according to another embodiment, it further comprises at least one biodegradable resin selected from the group consisting of: polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene adipate (PBA), polybutylene succinate adipate (PBSA), polybutylene succinate terephthalate (PBST), polyhydroxybutyrate-valerate (PHBV), polycaprolactone (PCL), polybutylene succinate adipate terephthalate (PBSAT), and thermoplastic starch (TPS).

[0023] In a composition for a biodegradable film according to another embodiment, it further comprises a polylactic acid (PLA) resin, wherein the weight ratio of the polyhydroxyalkanoate (PHA) resin to the polylactic acid (PLA) resin is 10:90 to 50:50.

[0024] In a composition for a biodegradable film according to another embodiment, it further comprises at least one additive selected from the group consisting of: chain extender, antioxidant, compatibilizer, weight increasing agent, nucleating agent, melt strength enhancer, and slip agent, wherein the content of the additive is 0.1 phr to 50 phr.

[0025] In another embodiment, a biodegradable film is provided, which comprises the composition for a biodegradable film.

[0026] In a biodegradable film of another embodiment, the tensile strength is from 10 MPa to 50 MPa and the elongation at break is 200% or more.

[0027] In another embodiment, a method for preparing a biodegradable film is provided, the method comprising: a first step of preparing a composition for the biodegradable film; and a second step of feeding the composition for the biodegradable film into an extruder to perform extrusion molding thereon.

[0028] In a method for preparing a biodegradable film of another embodiment, the first step includes mixing a polyhydroxyalkanoate (PHA) resin with a plasticizer having a melting temperature of from 95 °C to 250 °C.

[0029] Advantages of the present invention

[0030] A composition for a biodegradable film according to one embodiment comprises a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature within a specific range, wherein when it is extruded in an extruder, at a pressure of 46 bar or less within the extruder, the load (torque) applied to the screw is 70% or less. As a result, processability and productivity can be improved simultaneously, and an environmentally friendly biodegradable film and biodegradable product having excellent biodegradability and mechanical properties can be provided. Brief Description of the Drawings

[0031] Figure 1 is a partial cross-sectional view of an extruder used according to one embodiment.

[0032] [Explanation of Reference Numerals]

[0033] 100: Extruder

[0034] 110: Raw Material Feeder

[0035] 120: Compression Section

[0036] 130: Screw

[0037] 140: Head (Header)

[0038] 150: Die Detailed Description of the Embodiments

[0039] Best Mode for Carrying Out the Invention

[0040] The present disclosure will be described in detail below with reference to embodiments. The embodiments are not limited to those described below. Instead, they can be modified into various forms as long as the gist of the present invention is not changed.

[0041] In this specification, when a part is referred to as "comprising" an element, it should be understood to include other elements as well, rather than excluding other elements, unless otherwise explicitly stated.

[0042] In addition, unless otherwise specified, all numbers representing physical properties, dimensions, etc. of components used herein should be understood to be modified by the term "about".

[0043] In this specification, terms such as first, second, etc. are used to describe various components. However, the components should not be limited by these terms. These terms are only used to distinguish one component from another.

[0044] [Composition for biodegradable film]

[0045] According to one embodiment, there is provided a composition for a biodegradable film, the composition comprising a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature of 95°C to 250°C, wherein when the composition for the biodegradable film is fed into an extruder equipped with a screw at 6 rpm and extruded at a screw speed of 200 rpm at 170°C, the load (torque) applied to the screw is 70% or less at a pressure of 46 bar or less inside the extruder.

[0046] According to one embodiment, the composition for the biodegradable film is of technical importance because it contains a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature within a specific range, whereby an environmentally friendly biodegradable film and biodegradable products having excellent biodegradability and mechanical properties can be provided; and the fluidity of all the resins contained in the composition for the biodegradable film is improved at the molding temperature, and the melt index of the composition for the biodegradable film is increased, whereby during the extrusion molding process, the load (torque) applied to the screw satisfies 70% or less at a pressure of 46 bar or less inside the extruder; as a result, the load applied during the extrusion molding process (e.g., when using an extrusion device (extruder)) can be significantly reduced, the processability and productivity can be simultaneously improved, and the quality of the final product can be further improved.

[0047] Hereinafter, each component of the composition for the biodegradable film will be described in detail.

[0048] Polyhydroxyalkanoate (PHA) resin

[0049] According to one embodiment of the present disclosure, the composition for the biodegradable film comprises polyhydroxyalkanoate (PHA).

[0050] When the composition for a biodegradable film contains a polyhydroxyalkanoate (PHA) resin, biodegradability and mechanical properties such as tensile strength and elongation at break can be improved. When the composition for a biodegradable film is molded, processability and productivity can be simultaneously improved, and the quality of the biodegradable film and biodegradable products prepared therefrom can be further enhanced.

[0051] Polyhydroxyalkanoates (PHA) have physical properties similar to those of traditional petroleum-derived synthetic polymers such as poly(butylene adipate terephthalate) (PBAT), poly(butylene succinate) (PBS), poly(butylene succinate terephthalate) (PBST), and poly(butylene adipate succinate) (PBSA), showing complete biodegradability and excellent biocompatibility.

[0052] Specifically, polyhydroxyalkanoates (PHA) are natural thermoplastic polyester polymers accumulated in microbial cells. Since it is a biodegradable material, it can be composted and ultimately decomposed into carbon dioxide, water, and organic waste without generating toxic waste. In particular, due to the biodegradability of polyhydroxyalkanoates (PHA) in soil and the ocean, they have environmentally friendly characteristics.

[0053] The polyhydroxyalkanoate (PHA) can be a polyhydroxyalkanoate (PHA) homopolymer composed of one monomer, or a polyhydroxyalkanoate (PHA) copolymer containing two or more different monomers. Alternatively, the polyhydroxyalkanoate (PHA) can include a polyhydroxyalkanoate (PHA) homopolymer and a polyhydroxyalkanoate (PHA) copolymer.

[0054] When the polyhydroxyalkanoate (PHA) is a copolymer, it can be, for example, a copolymerized polyhydroxyalkanoate (PHA) containing two or more different repeating units, where different monomers are randomly distributed in the polymer chain.

[0055] Examples of monomers that can be contained in polyhydroxyalkanoates (PHA) include 2-hydroxybutyrate, lactic acid, glycolic acid, 3-hydroxybutyrate (hereinafter referred to as 3-HB), 3-hydroxypropionate (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-HO), 3-hydroxynonanoate (hereinafter referred to as 3-HN), 3-hydroxydecanoate (hereinafter referred to as 3-HD), 3-hydroxydodecanoate (hereinafter referred to as 3-HDd), 4-hydroxybutyrate (hereinafter referred to as 4-HB), 4-hydroxyvalerate (hereinafter referred to as 4-HV), 5-hydroxyvalerate (hereinafter referred to as 5-HV), and 6-hydroxyhexanoate (hereinafter referred to as 6-HH). The polyhydroxyalkanoate (PHA) can contain at least one monomer selected from the above.

[0056] Polyhydroxyalkanoate (PHA) resins may include at least one monomer selected from the group consisting of 4-HB, 3-HB, 3-HP, 3-HV, 3-HH, 4-HV, 5-HV, and 6-HH.

[0057] For example, polyhydroxyalkanoate (PHA) may include a polyhydroxyalkanoate (PHA) homopolymer composed of monomers selected from the group consisting of 4-HB, 3-HB, 3-HP, 3-HV, 3-HH, 4-HV, 5-HV, and 6-HH; or a polyhydroxyalkanoate (PHA) copolymer containing at least one monomer selected from the group consisting of 4-HB, 3-HB, 3-HP, 3-HV, 3-HH, 4-HV, 5-HV, and 6-HH.

[0058] Specifically, polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) homopolymer composed of monomers selected from the group consisting of 4-HB and 3-HB; or a polyhydroxyalkanoate (PHA) copolymer containing at least one monomer selected from the group consisting of 4-HB and 3-HB.

[0059] More specifically, polyhydroxyalkanoate (PHA) may include 4-HB monomers.

[0060] Polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) homopolymer composed of 4-HB monomers.

[0061] In addition, polyhydroxyalkanoate (PHA) may include a polyhydroxyalkanoate (PHA) copolymer containing 4-HB monomers.

[0062] For example, polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) copolymer containing 4-HB monomers and further containing a monomer different from 4-HB monomers, or further containing two, three, four, five, six, or more monomers different from each other.

[0063] According to one embodiment, polyhydroxyalkanoate (PHA) may include 4-HB monomers; and at least one monomer selected from the group consisting of 3-HB, 3-HP, 3-HV, 3-HH, 4-HV, 5-HV, and 6-HH. More specifically, polyhydroxyalkanoate (PHA) may include a polyhydroxyalkanoate (PHA) copolymer containing 3-HB monomers and 4-HB monomers.

[0064] For example, polyhydroxyalkanoate (PHA) may be poly-3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter referred to as 3HB-co-4HB).

[0065] In addition, polyhydroxyalkanoates (PHA) may include isomers. For example, polyhydroxyalkanoates (PHA) may include structural isomers, enantiomers, or geometric isomers. Specifically, polyhydroxyalkanoates (PHA) may include structural isomers.

[0066] According to one embodiment, in order to be suitable for biodegradable films and products, and in order to obtain the desired excellent mechanical properties as well as processability and productivity in molding processes, specifically, polyhydroxyalkanoates (PHA) containing 4-HB monomers may be used. In this case, it may be important to control the content ratio of 4-HB monomers.

[0067] For example, polyhydroxyalkanoates (PHA) may include polyhydroxyalkanoate copolymers (PHA copolymers) containing 4-HB monomers, wherein the polyhydroxyalkanoates (PHA) may contain 4-hydroxybutyrate (4-HB) monomers in an amount of 1 mol% to 99 mol% based on the total molar amount of monomers contained in the polyhydroxyalkanoate (PHA) copolymer.

[0068] Specifically, polyhydroxyalkanoates (PHA) may include polyhydroxyalkanoate (PHA) copolymers containing 3-HB monomers and 4-HB monomers, wherein the polyhydroxyalkanoate (PHA) copolymer may contain 4-hydroxybutyrate (4-HB) monomers in an amount of 1 mol% to 99 mol% based on the total molar amount of 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers.

[0069] For example, the polyhydroxyalkanoate (PHA) copolymer may contain 4-hydroxybutyrate (4-HB) monomers in an amount of 1 mol% or more, 2 mol% or more, 3 mol% or more, 5 mol% or more, or 10 mol% or more, and 99 mol% or less, 95 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, 75 mol% or less, 70 mol% or less, 65 mol% or less, or 60 mol% or less based on the total molar amount of 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers.

[0070] Specifically, the polyhydroxyalkanoate (PHA) copolymer may comprise from 1 mol% to 99 mol%, from 1 mol% to 95 mol%, from 1 mol% to 90 mol%, from 1 mol% to 89 mol%, from 1 mol% to 85 mol%, from 1 mol% to 80 mol%, from 1 mol% to 79 mol%, from 1 mol% to 75 mol%, from 1 mol% to 70 mol%, from 1 mol% to 65 mol%, from 1 mol% to 60 mol%, from 1 mol% to 55 mol%, from 1 mol% to 50 mol%, from 2 mol% to 55 mol%, from 3 mol% to 55 mol%, from 3 mol% to 50 mol%, from 5 mol% to 55 mol%, from 5 mol% to 50 mol%, from 10 mol% to 55 mol%, from 10 mol% to 50 mol%, from 15 mol% to 60 mol%, from 15 mol% to 55 mol%, from 15 mol% to 50 mol%, from 20 mol% to 60 mol%, from 20 mol% to 55 mol%, from 20 mol% to 50 mol%, from 25 mol% to 60 mol%, from 25 mol% to 55 mol%, from 25 mol% to 50 mol%, from 25 mol% to 45 mol%, from 25 mol% to 40 mol%, from 30 mol% to 60 mol%, from 30 mol% to 55 mol%, from 30 mol% to 50 mol%, from 30 mol% to 45 mol%, from 30 mol% to 40 mol%, from 35 mol% to 60 mol%, from 35 mol% to 55 mol%, from 35 mol% to 50 mol%, from 40 mol% to 60 mol%, from 40 mol% to 55 mol%, or from 45 mol% to 55 mol of 4-hydroxybutyrate (4-HB) monomers based on the total molar amount of 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers.

[0071] For example, the polyhydroxyalkanoate (PHA) resin may include a resin comprising 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers, wherein it may comprise from 1 mol% to 60 mol% of 4-hydroxybutyrate (4-HB) monomers based on the total molar amount of 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers.

[0072] When the content of the 4-HB monomers satisfies the above range, it may be more conducive to achieving the desired effects according to the embodiments; in particular, the processability and productivity during the molding process can be improved simultaneously, as well as the excellent mechanical properties.

[0073] In addition, the polyhydroxyalkanoate (PHA) contains at least one 4-HB monomer, and the crystallinity of the polyhydroxyalkanoate (PHA) can be controlled by adjusting the content of the 4-HB monomer. That is to say, the polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) copolymer with adjusted crystallinity.

[0074] The polyhydroxyalkanoate (PHA) with regulated crystallinity can be a polyhydroxyalkanoate (PHA) in which its crystallinity and amorphousness are regulated with the increase of irregularities in its molecular structure. Specifically, the type and ratio of monomers or the type and / or content of isomers can be regulated.

[0075] Meanwhile, the glass transition temperature (Tg) of the polyhydroxyalkanoate (PHA) can be, for example, -45 °C to 80 °C, -35 °C to 80 °C, -30 °C to 80 °C, -25 °C to 75 °C, -20 °C to 70 °C, -35 °C to 5 °C, -25 °C to 5 °C, -35 °C to 0 °C, -25 °C to 0 °C, -30 °C to -10 °C, -35 °C to -15 °C, -35 °C to -20 °C, -30 °C to -20 °C, -20 °C to 0 °C, -15 °C to 0 °C, or -15 °C to -5 °C.

[0076] The crystallization temperature (Tc) of the polyhydroxyalkanoate (PHA) may, for example, be unmeasurable, or can be, for example, 60 °C to 120 °C, 70 °C to 120 °C, 75 °C to 120 °C, 75 °C to 115 °C, 75 °C to 110 °C, or 90 °C to 110 °C.

[0077] The melting temperature (Tm) of the polyhydroxyalkanoate (PHA) may, for example, be unmeasurable, or can be, for example, 100 °C to 170 °C, 110 °C to 150 °C, or 120 °C to 140 °C.

[0078] In addition, the weight-average molecular weight of the polyhydroxyalkanoate (PHA) can be, for example, from 10,000 grams per mole to 1,200,000 grams per mole. For example, the weight-average molecular weight of the polyhydroxyalkanoate (PHA) can be from 50,000 grams per mole to 1,200,000 grams per mole, from 100,000 grams per mole to 1,200,000 grams per mole, from 50,000 grams per mole to 1,000,000 grams per mole, from 100,000 grams per mole to 1,000,000 grams per mole, from 200,000 grams per mole to 1,200,000 grams per mole, from 250,000 grams per mole to 1,150,000 grams per mole, from 300,000 grams per mole to 1,100,000 grams per mole, from 350,000 grams per mole to 1,000,000 grams per mole, from 350,000 grams per mole to 950,000 grams per mole, from 100,000 grams per mole to 900,000 grams per mole, from 200,000 grams per mole to 800,000 grams per mole, from 200,000 grams per mole to 700,000 grams per mole, from 250,000 grams per mole to 650,000 grams per mole, from 200,000 grams per mole to 400,000 grams per mole, from 300,000 grams per mole to 800,000 grams per mole, from 300,000 grams per mole to 600,000 grams per mole, from 500,000 grams per mole to 1,200,000 grams per mole, from 500,000 grams per mole to 1,000,000 grams per mole, from 550,000 grams per mole to 1,050,000 grams per mole, from 550,000 grams per mole to 900,000 grams per mole, or from 600,000 grams per mole to 900,000 grams per mole.

[0079] The melt index (MI) of the polyhydroxyalkanoate (PHA) when measured according to ASTM D1238 at a temperature of 165 °C and a load of 2.16 kg can be 0.1 grams per 10 minutes or higher, 0.2 grams per 10 minutes or higher, 0.5 grams per 10 minutes or higher, 1 gram per 10 minutes or higher, 1.5 grams per 10 minutes or higher, or 2 grams per 10 minutes or higher, and 5 grams per 10 minutes or lower, 4.5 grams per 10 minutes or lower, or 4 grams per 10 minutes or lower.

[0080] For example, the melt index (MI) of polyhydroxyalkanoate (PHA) measured according to ASTM D1238 at a temperature of 165 °C and a load of 2.16 kg can be from 0.1 g / 10 min to 5 g / 10 min, from 0.1 g / 10 min to 4 g / 10 min, from 0.1 g / 10 min to 3 g / 10 min, from 0.1 g / 10 min to 2 g / 10 min, from 0.5 g / 10 min to 5 g / 10 min, from 0.5 g / 10 min to 4 g / 10 min, from 0.5 g / 10 min to 3 g / 10 min, from 0.5 g / 10 min to 2 g / 10 min, from 1 g / 10 min to 5 g / 10 min, from 1 g / 10 min to 4 g / 10 min, or from 1 g / 10 min to 3 g / 10 min.

[0081] Meanwhile, the polyhydroxyalkanoate (PHA) can include a combination of two or more types of polyhydroxyalkanoate (PHA) having different crystallinities. That is, by mixing two or more types of polyhydroxyalkanoate (PHA) having different crystallinities, the polyhydroxyalkanoate (PHA) can be adjusted to have a 4-HB monomer content within the above specific range.

[0082] Specifically, the polyhydroxyalkanoate (PHA) can contain a first polyhydroxyalkanoate (PHA) resin, a second polyhydroxyalkanoate (PHA) resin, or a mixed resin of the first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin.

[0083] The first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin can be different from each other in terms of the content of 4-HB monomer, glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm).

[0084] Specifically, the first polyhydroxyalkanoate (PHA) resin can contain, for example, 15 mol% to 60 mol%, 15 mol% to 55 mol%, 20 mol% to 55 mol%, 25 mol% to 55 mol%, 30 mol% to 55 mol%, 35 mol% to 55 mol%, 20 mol% to 50 mol%, 25 mol% to 50 mol%, 30 mol% to 50 mol%, 35 mol% to 50 mol%, or 20 mol% to 40 mol% of 4-HB monomer based on the total molar amount of monomers contained in the first polyhydroxyalkanoate (PHA).

[0085] The glass transition temperature (Tg) of the first polyhydroxyalkanoate (PHA) resin can be, for example, -45 °C to -10 °C, -35 °C to -10 °C, -35 °C to -15 °C, -35 °C to -20 °C, or -30 °C to -20 °C.

[0086] The crystallization temperature (Tc) of the first polyhydroxyalkanoate (PHA) resin may, for example, be unmeasurable, or may be, for example, from 60 °C to 120 °C, from 60 °C to 110 °C, from 70 °C to 120 °C, or from 75 °C to 115 °C.

[0087] The melting temperature (Tm) of the first polyhydroxyalkanoate (PHA) resin may, for example, be unmeasurable, or may be, for example, from 100 °C to 170 °C, from 100 °C to 160 °C, from 110 °C to 160 °C, or from 120 °C to 150 °C.

[0088] The weight-average molecular weight (Mw) of the first polyhydroxyalkanoate (PHA) resin may be, for example, from 10,000 g / mol to 1,200,000 g / mol, from 10,000 g / mol to 1,000,000 g / mol, from 50,000 g / mol to 1,000,000 g / mol, from 50,000 g / mol to 1,200,000 g / mol, from 200,000 g / mol to 1,200,000 g / mol, from 300,000 g / mol to 1,000,000 g / mol, from 100,000 g / mol to 900,000 g / mol, from 500,000 g / mol to 900,000 g / mol, from 200,000 g / mol to 800,000 g / mol, or from 200,000 g / mol to 400,000 g / mol.

[0089] The melt index (MI) of the first polyhydroxyalkanoate (PHA) when measured according to ASTM D1238 at a temperature of 165 °C and a load of 2.16 kg may be 0.1 g / 10 min or higher, 0.2 g / 10 min or higher, 0.5 g / 10 min or higher, 1 g / 10 min or higher, 1.5 g / 10 min or higher, or 2 g / 10 min or higher, and 5 g / 10 min or lower, 4.5 g / 10 min or lower, or 4 g / 10 min or lower.

[0090] For example, the melt index (MI) of the first polyhydroxyalkanoate (PHA) resin measured according to ASTM D1238 at a temperature of 165 °C and a load of 2.16 kg may be from 0.1 g / 10 min to 5 g / 10 min, from 0.1 g / 10 min to 4 g / 10 min, from 0.1 g / 10 min to 3 g / 10 min, from 0.1 g / 10 min to 2 g / 10 min, from 0.5 g / 10 min to 5 g / 10 min, from 0.5 g / 10 min to 4 g / 10 min, from 0.5 g / 10 min to 3 g / 10 min, from 0.5 g / 10 min to 2 g / 10 min, from 1 g / 10 min to 5 g / 10 min, from 1 g / 10 min to 4 g / 10 min, or from 1 g / 10 min to 3 g / 10 min.

[0091] Meanwhile, the second polyhydroxyalkanoate (PHA) resin may contain 4-HB monomers in an amount of 0.1 mol% to 30 mol% based on the total molar amount of monomers contained in the second polyhydroxyalkanoate (PHA) resin. For example, the second polyhydroxyalkanoate (PHA) resin may contain 0.1 mol% to 30 mol%, 0.5 mol% to 30 mol%, 1 mol% to 30 mol%, 3 mol% to 30 mol%, 1 mol% to 28 mol%, 1 mol% to 25 mol%, 1 mol% to 24 mol%, 1 mol% to 20 mol%, 1 mol% to 15 mol%, 2 mol% to 25 mol%, 3 mol% to 25 mol%, 3 mol% to 24 mol%, 5 mol% to 24 mol%, 5 mol% to 20 mol%, greater than 5 mol% to less than 20 mol%, 7 mol% to 20 mol%, 10 mol% to 20 mol%, 15 mol% to 25 mol%, or 15 mol% to 24 mol% of 4-HB monomers.

[0092] The first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin may differ from each other in the content of 4-HB monomers.

[0093] The glass transition temperature (Tg) of the second polyhydroxyalkanoate (PHA) resin may be, for example, -30°C to 80°C, -30°C to 10°C, -25°C to 5°C, -25°C to 0°C, -20°C to 0°C, or -15°C to 0°C.

[0094] The glass transition temperature (Tg) of the first polyhydroxyalkanoate (PHA) resin and the glass transition temperature (Tg) of the second polyhydroxyalkanoate (PHA) resin may differ from each other.

[0095] The crystallization temperature (Tc) of the second polyhydroxyalkanoate (PHA) resin may be, for example, 70°C to 120°C, 75°C to 115°C, or 80°C to 110°C, or may not be measurable.

[0096] The melting temperature (Tm) of the second polyhydroxyalkanoate (PHA) resin may be, for example, 100°C to 170°C, 105°C to 165°C, 110°C to 160°C, 100°C to 150°C, 115°C to 155°C, 120°C to 160°C, or 120°C to 150°C.

[0097] The weight-average molecular weight (Mw) of the second polyhydroxyalkanoate (PHA) resin can be from 10,000 g / mol to 1,200,000 g / mol, from 50,000 g / mol to 1,100,000 g / mol, from 100,000 g / mol to 1,000,000 g / mol, from 300,000 g / mol to 1,000,000 g / mol, from 100,000 g / mol to 900,000 g / mol, from 200,000 g / mol to 800,000 g / mol, from 200,000 g / mol to 600,000 g / mol, from 200,000 g / mol to 400,000 g / mol, or from 400,000 g / mol to 700,000 g / mol.

[0098] Specifically, the glass transition temperature (Tg) of the first polyhydroxyalkanoate (PHA) resin is from -35°C to -15°C, the second polyhydroxyalkanoate (PHA) resin satisfies at least one property selected from a glass transition temperature (Tg) of from -15°C to 0°C, a crystallization temperature (Tc) of from 80°C to 110°C, and a melting temperature (Tm) of from 120°C to 160°C, and the glass transition temperature (Tg) of the first polyhydroxyalkanoate (PHA) resin and the glass transition temperature (Tg) of the second polyhydroxyalkanoate (PHA) resin can be different from each other. In addition, the crystallization temperature (Tc) and the melting temperature (Tm) of the first polyhydroxyalkanoate (PHA) resin may not be measurable.

[0099] The melt index (MI) of the second polyhydroxyalkanoate (PHA) when measured according to ASTM D1238 at a temperature of 165°C and a load of 2.16 kg can be 0.1 g / 10 min or higher, 0.2 g / 10 min or higher, 0.5 g / 10 min or higher, 1 g / 10 min or higher, 1.5 g / 10 min or higher, or 2 g / 10 min or higher, and 5 g / 10 min or lower, 4.5 g / 10 min or lower, or 4 g / 10 min or lower.

[0100] For example, the melt index (MI) of the second polyhydroxyalkanoate (PHA) resin measured according to ASTM D1238 at a temperature of 165°C and a load of 2.16 kg can be from 0.1 g / 10 min to 5 g / 10 min, from 0.1 g / 10 min to 4 g / 10 min, from 0.1 g / 10 min to 3 g / 10 min, from 0.1 g / 10 min to 2 g / 10 min, from 0.5 g / 10 min to 5 g / 10 min, from 0.5 g / 10 min to 4 g / 10 min, from 0.5 g / 10 min to 3 g / 10 min, from 0.5 g / 10 min to 2 g / 10 min, from 1 g / 10 min to 5 g / 10 min, from 1 g / 10 min to 4 g / 10 min, or from 1 g / 10 min to 3 g / 10 min.

[0101] The melt index (MI) of the first polyhydroxyalkanoate (PHA) resin and the melt index (MI) of the second polyhydroxyalkanoate (PHA) resin can be different from each other.

[0102] When the first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin each satisfy at least one of the content of 4-HB monomer, glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and melt index (MI) in the above ranges, it can be more conducive to achieving the desired effects of the present disclosure.

[0103] In addition, the first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin can each be a polyhydroxyalkanoate (PHA) with controlled crystallinity.

[0104] For example, the first polyhydroxyalkanoate (PHA) resin can include an amorphous polyhydroxyalkanoate (PHA) resin (hereinafter referred to as aPHA resin), and the second polyhydroxyalkanoate (PHA) resin can include a semi-crystalline polyhydroxyalkanoate (PHA) resin (hereinafter referred to as scPHA resin).

[0105] Specifically, the first polyhydroxyalkanoate (PHA) resin can be an aPHA resin or a mixed resin of an aPHA resin and an scPHA resin.

[0106] Specifically, the second polyhydroxyalkanoate (PHA) resin can be an scPHA resin or a mixed resin of an aPHA resin and an scPHA resin.

[0107] The aPHA resin and the scPHA resin can be different from each other in terms of the content of 4-HB monomer, glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), melt index (MI), etc.

[0108] The aPHA resin can contain, for example, 4-HB monomer in an amount of 25 mol% to 50 mol% based on the total molar amount of monomers contained in the polyhydroxyalkanoate (PHA) resin.

[0109] The glass transition temperature (Tg) of the aPHA resin can be, for example, -35°C to -20°C.

[0110] The crystallization temperature (Tc) of the aPHA resin may not be measurable.

[0111] The melting temperature (Tm) of the aPHA resin may not be measurable.

[0112] The scPHA resin may contain, for example, 4-HB monomers in an amount of 1 mol% to less than 25 mol% based on the total moles of monomers contained in the polyhydroxyalkanoate (PHA) resin.

[0113] The glass transition temperature (Tg) of the scPHA resin may be from -20 °C to 0 °C.

[0114] The crystallization temperature (Tc) of the scPHA resin may be from 75 °C to 115 °C.

[0115] The melting temperature (Tm) of the scPHA resin may be from 110 °C to 160 °C.

[0116] According to one embodiment, when the polyhydroxyalkanoate (PHA) comprises a mixed resin of a first polyhydroxyalkanoate (PHA) resin and a second polyhydroxyalkanoate (PHA) resin, the weight ratio of the first polyhydroxyalkanoate (PHA) resin to the second polyhydroxyalkanoate (PHA) resin may be, for example, 1:0.5 to 3, 1:0.5 to 2.5, or 1:0.5 to 2.

[0117] According to one embodiment, the composition for the biodegradable film may contain 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, or 30 parts by weight or more, and 100 parts by weight or less, less than 100 parts by weight, 95 parts by weight or less, 90 parts by weight or less, 85 parts by weight or less, or 80 parts by weight or less of the polyhydroxyalkanoate (PHA) resin based on 100 parts by weight of all the resins contained in the composition for the biodegradable film.

[0118] For example, the composition for the biodegradable film may contain 10 parts by weight to 100 parts by weight, 10 parts by weight to 90 parts by weight, 10 parts by weight to 80 parts by weight, 10 parts by weight to 70 parts by weight, 10 parts by weight to 60 parts by weight, 20 parts by weight to 90 parts by weight, 20 parts by weight to 80 parts by weight, 20 parts by weight to 70 parts by weight, 20 parts by weight to 60 parts by weight, 20 parts by weight to 50 parts by weight, 30 parts by weight to 90 parts by weight, 30 parts by weight to 80 parts by weight, 30 parts by weight to 70 parts by weight, 30 parts by weight to 60 parts by weight, 30 parts by weight to 50 parts by weight, or 30 parts by weight to 40 parts by weight of the polyhydroxyalkanoate (PHA) resin based on 100 parts by weight of all the resins contained in the composition for the biodegradable film.

[0119] When the content of the polyhydroxyalkanoate (PHA) resin satisfies the above range, the mechanical properties such as tensile strength and elongation at break, processability and productivity during the molding process can be improved simultaneously.

[0120] Biodegradable resin

[0121] The composition for a biodegradable film according to one embodiment may further include at least one selected from the group consisting of aliphatic polyester-based biodegradable resins and aliphatic / aromatic copolyester-based biodegradable resins as a component that provides biodegradability while ensuring mechanical properties suitable for a biodegradable film or a biodegradable product prepared using the same.

[0122] Specifically, the type of the biodegradable resin is not particularly limited as long as it is commonly used. For example, the composition for a biodegradable film may include at least one biodegradable resin selected from the group consisting of poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), poly(butylene adipate) (PBA), poly(butylene succinate adipate) (PBSA), poly(butylene succinate terephthalate) (PBST), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polycaprolactone (PCL), poly(butylene succinate adipate terephthalate) (PBSAT), and thermoplastic starch (TPS). Specifically, the biodegradable resin may include at least one selected from the group consisting of poly(butylene adipate terephthalate) (PBAT), polylactic acid (PLA), and thermoplastic starch (TPS). More specifically, the biodegradable resin may include at least one selected from the group consisting of poly(butylene adipate terephthalate) (PBAT) and polylactic acid (PLA).

[0123] According to one embodiment, the composition for a biodegradable film may further include a polylactic acid (PLA) resin.

[0124] Since the polylactic acid (PLA) resin is different from petroleum-based resins but is biomass-based, it can be used as a recyclable resource and is environmentally friendly because it is biodegradable by moisture and microorganisms when landfilled.

[0125] Meanwhile, the weight-average molecular weight (Mw) of the polylactic acid (PLA) may be from 10,000 to 1,000,000 g / mol, for example, from 30,000 to 500,000 g / mol, from 100,000 to 300,000 g / mol, or from 100,000 to 200,000 g / mol. The weight-average molecular weight (Mw) can be measured by gel permeation chromatography (GPC).

[0126] The polylactic acid (PLA) may include L-lactic acid, D-lactic acid, D,L-lactic acid, or a combination thereof.

[0127] Specifically, the polylactic acid (PLA) may be a random copolymer of L-lactic acid and D-lactic acid.

[0128] The melting temperature (Tm) of polylactic acid (PLA) can be from 100 °C to 300 °C, from 120 °C to 250 °C, or from 120 °C to 200 °C.

[0129] The glass transition temperature (Tg) of polylactic acid (PLA) can be from 30 °C to 100 °C, from 30 °C to 80 °C, from 40 °C to 80 °C, or from 45 °C to 70 °C.

[0130] Specifically, the composition for the biodegradable film may contain from more than 0 part by weight, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 30 parts by weight or more, 40 parts by weight or more, 45 parts by weight or more, 50 parts by weight or more, 55 parts by weight or more, or 60 parts by weight or more of polylactic acid (PLA) resin based on 100 parts by weight of all the resins contained in the composition for the biodegradable film. In addition, the composition for the biodegradable film may contain 90 parts by weight or less, 85 parts by weight or less, 80 parts by weight or less, 75 parts by weight or less, or 70 parts by weight or less of polylactic acid (PLA) resin based on 100 parts by weight of all the resins contained in the composition for the biodegradable film.

[0131] For example, the composition for the biodegradable film may contain from 5 parts by weight to 90 parts by weight, from 10 parts by weight to 90 parts by weight, from 20 parts by weight to 90 parts by weight, from 30 parts by weight to 90 parts by weight, from 40 parts by weight to 90 parts by weight, from 50 parts by weight to 90 parts by weight, from 60 parts by weight to 90 parts by weight, from 10 parts by weight to 80 parts by weight, from 20 parts by weight to 80 parts by weight, from 30 parts by weight to 80 parts by weight, from 40 parts by weight to 80 parts by weight, from 50 parts by weight to 80 parts by weight, from 60 parts by weight to 80 parts by weight, from 10 parts by weight to 70 parts by weight, from 20 parts by weight to 70 parts by weight, from 30 parts by weight to 70 parts by weight, from 40 parts by weight to 70 parts by weight, from 50 parts by weight to 70 parts by weight, or from 60 parts by weight to 70 parts by weight of polylactic acid (PLA) resin based on 100 parts by weight of all the resins contained in the composition for the biodegradable film.

[0132] According to one embodiment, the composition for the biodegradable film further contains a polylactic acid (PLA) resin, wherein the weight ratio of the polyhydroxyalkanoate (PHA) resin to the polylactic acid (PLA) resin can be from 10:90 to 50:50, from 20:80 to 50:50, from 30:70 to 50:50, or from 30:70 to 40:60.

[0133] When the composition for a biodegradable film contains a polyhydroxyalkanoate (PHA) resin and a polylactic acid (PLA) resin, and when the weight ratio of the polyhydroxyalkanoate (PHA) resin to the polylactic acid (PLA) resin satisfies the above range, the compatibility between the resins is excellent, and it can be more beneficial to achieve the desired effects.

[0134] In addition, the composition for a biodegradable film may contain more than 0 parts by weight, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 30 parts by weight or more, 40 parts by weight or more, 45 parts by weight or more, 50 parts by weight or more, 55 parts by weight or more, or 60 parts by weight or more, and 90 parts by weight or less, 85 parts by weight or less, 80 parts by weight or less, 75 parts by weight or less, or 70 parts by weight or less of a biodegradable resin based on 100 parts by weight of all the resins contained in the composition for a biodegradable film.

[0135] If the composition for a biodegradable film contains a biodegradable resin within the above range, mechanical properties suitable for use as biodegradable molded articles can be achieved; thus, the advantage is that it can be used in various ways. For example, since the composition for a biodegradable film also contains a biodegradable resin such as a polylactic acid (PLA) resin, the tensile strength and elongation can be improved simultaneously.

[0136] Plasticizer

[0137] The composition for a biodegradable film contains a plasticizer having a melting temperature of 95°C to 250°C. Specifically, the composition for a biodegradable film may contain a plasticizer derived from natural sources and having a melting temperature of 95°C to 250°C.

[0138] When the melting temperature of the plasticizer is within the above range, the plasticizer can turn into a liquid phase with high fluidity during the film forming process, thereby improving the melt fluidity of the composition for a biodegradable film. In particular, when a plasticizer derived from natural sources is used, it can be more advantageous in terms of safety when used for food packaging materials or sanitary products.

[0139] The melting temperature of the plasticizer can be 100°C to 250°C, 120°C to 250°C, 130°C to 250°C, 130°C to 220°C, 130°C to 210°C, 130°C to 200°C, 140°C to 180°C, 140°C to 170°C, 140°C to less than 170°C, 140°C to 165°C, or 140°C to 160°C. When the melting temperature of the plasticizer satisfies the above range, it has excellent melt fluidity, which can be very advantageous in terms of processability and productivity.

[0140] The plasticizer may include an adipic acid-based plasticizer. Specifically, the plasticizer may be adipic acid.

[0141] In particular, adipic acid is one of the additives derived from nature, harmless to the human body, and can also be used as an edible additive. Therefore, when the composition for a biodegradable film containing adipic acid is used for food packaging materials or hygiene products, it has a great advantage of having fewer side effects on the human body.

[0142] An adipic acid-based plasticizer, such as adipic acid, is a substance with a high melting temperature of about 152.1 °C, which is convenient for handling in a solid phase at room temperature and transforms into a liquid phase with high fluidity at a molding temperature of about 170 °C or higher; therefore, adipic acid can be used as a plasticizer that can improve the melt fluidity of the composition for a biodegradable film.

[0143] In particular, different from conventional polyester polymer resins, the polyhydroxyalkanoate (PHA) resin contained in the composition for a biodegradable film has a high molecular weight or ultra-high molecular weight within the above range. Generally, the higher the molecular weight, the lower the melt fluidity. Therefore, when the composition for a biodegradable film contains a plasticizer such as an adipic acid-based plasticizer with a melting temperature within the above specific range, the fluidity of all the resins contained in the composition for a biodegradable film can be improved at the molding temperature, and the overall melt index of the composition for a biodegradable film can be increased.

[0144] When preparing a biodegradable film from the composition for a biodegradable film, the melt index of the composition for a biodegradable film or the fluidity of the resin contained in the composition can be one of the most important factors in terms of processability and productivity.

[0145] Specifically, when the composition for a biodegradable film contains a plasticizer with a melting temperature within the above specific range, the load applied when using an extrusion molding device (extruder) during the molding process of the biodegradable film or biodegradable product can be significantly reduced, and the quality of the final product can be further improved.

[0146] For example, when the composition for a biodegradable film contains a plasticizer with a melting temperature within the above specific range, the load applied to the extrusion device during the extrusion molding process, specifically, the load (torque) applied to the screw in the extruder, can be reduced, thereby further improving processability and productivity and further improving the quality of the final product.

[0147] The content of the plasticizer can be 0.01 phr or more, 0.05 phr or more, 0.07 phr or more, or 0.1 phr or more, and 10 phr or less, 8 phr or less, 7 phr or less, 5 phr or less, 4 phr or less, 3 phr or less, 2 phr or less, 1 phr or less, less than 1 phr, 0.9 phr or less, 0.8 phr or less, 0.7 phr or less, 0.6 phr or less, or 0.5 phr or less.

[0148] For example, the content of the plasticizer can be from 0.01 phr to 10 phr, from 0.01 phr to 9 phr, from 0.01 phr to 8 phr, from 0.01 phr to 7 phr, from 0.01 phr to 6 phr, from 0.01 phr to 5 phr, from 0.01 phr to 4 phr, from 0.01 phr to 3 phr, from 0.01 phr to 2 phr, from 0.01 phr to 1 phr, from 0.01 phr to less than 1 phr, from 0.01 phr to 0.99 phr, from 0.01 phr to 0.95 phr, from 0.01 phr to 0.9 phr, from 0.01 phr to 0.8 phr, from 0.01 phr to 0.7 phr, from 0.01 phr to 0.6 phr, from 0.01 phr to 0.5 phr, from 0.1 phr to 10 phr, from 0.1 phr to 9 phr, from 0.1 phr to 8 phr, from 0.1 phr to 7 phr, from 0.1 phr to 6 phr, from 0.1 phr to 5 phr, from 0.1 phr to 4 phr, from 0.1 phr to 3 phr, from 0.1 phr to 2 phr, from 0.1 phr to 1 phr, from 0.1 phr to 0.99 phr, from 0.1 phr to 0.95 phr, from 0.1 phr to 0.9 phr, from 0.1 phr to 0.8 phr, from 0.1 phr to 0.7 phr, or from 0.1 phr to 0.6 phr.

[0149] Phr (parts per hundred resin) is a unit, which means the input amount of the material added to every 100 weight parts of the total polymer resin (1 phr: 1 g input amount when the polymer resin is 100 g).

[0150] When the content of the plasticizer meets the above range, the fluidity of all the resins contained in the composition for the biodegradable film can be improved, and the melt index of the composition for the biodegradable film can be adjusted to a range suitable for molding; therefore, when using a molding device, especially an extruder, the applied load can be significantly reduced, the processability and productivity can be improved simultaneously, and the quality of the final product can be further improved.

[0151] Meanwhile, the composition for the biodegradable film may include additional plasticizers in addition to the plasticizer having a melting temperature within the above specific range.

[0152] The additional plasticizers may include at least one commonly used plasticizer, such as glycerol, sorbitol, 1,4-butanediol, ethylene glycol, maltose, sucrose, cyclodextrin, glucose, propylene glycol, urea, polyethylene glycol, and polypropylene glycol, but are not limited thereto.

[0153] When the composition for the biodegradable film is used as a mixture of a plasticizer having a melting temperature within a specific range and an additional plasticizer, the weight ratio of the plasticizer having a melting temperature within a specific range to the additional plasticizer may be 1:9 to 9.9:0.1, 2:8 to 8:2, 3:7 to 7:3, or 5:5 to 9.9:0.1, but is not limited to this range as long as the desired effect is not impaired.

[0154] Additives

[0155] The composition for the biodegradable film may further include at least one additive selected from the group consisting of chain extenders, antioxidants, compatibilizers, weight increasing agents, nucleating agents, melt strength enhancers, and slip agents.

[0156] The content of the additive may be 0.1 phr to 50 phr based on 100 parts by weight of all the resins contained in the composition for the biodegradable film. For example, the content of the additive may be 0.1 phr or more, 0.5 phr or more, 1 phr or more, 1.5 phr or more, or 2 phr or more, and 30 phr or less, 28 phr or less, 25 phr or less, 20 phr or less, 15 phr or less, 10 phr or less, 8 phr or less, or 5 phr or less.

[0157] The chain extender can adjust the composition for the biodegradable film to have a desired viscosity that meets commercial performance, so as to be applied to various molding processes that require high viscosity or ultra-high viscosity conditions, such as blow molding, injection molding, and extrusion molding. It also has the great advantage of simultaneously improving processability and productivity.

[0158] The chain extender may include at least one selected from the group consisting of epoxy-based compounds, acrylic-based compounds, and isocyanate-based compounds. As a specific example, the chain extender may include an epoxy-based compound.

[0159] The epoxy-based compound may contain an epoxy group as a functional group. The chain extender may contain 1 to 30, 1 to 20, 1 to 15, 2 to 10, 3 to 10, 5 to 10, 2 to 9, or 5 to 9 epoxy groups.

[0160] For example, epoxy-based compounds can include compounds having a molecular weight of from 100 grams per mole to 50,000 grams per mole, from 100 grams per mole to 35,000 grams per mole, from 100 grams per mole to 30,000 grams per mole, from 100 grams per mole to 25,000 grams per mole, from 100 grams per mole to 20,000 grams per mole, from 200 grams per mole to 10,000 grams per mole, from 300 grams per mole to 10,000 grams per mole, from 300 grams per mole to 8,000 grams per mole, from 300 grams per mole to 400 grams per mole, from 5,000 grams per mole to 8,000 grams per mole, from 6,000 grams per mole to 8,000 grams per mole, or from 7,000 grams per mole to 8,000 grams per mole.

[0161] Epoxy-based compounds can include styrene acrylate copolymers having 5 to 9 epoxy groups, bisphenol A diglycidyl ether polymers having 2 epoxy groups, or combinations thereof. More specifically, epoxy-based compounds can include styrene acrylate copolymers containing 5 or 9 epoxy groups. For example, epoxy-based compounds can include Joncryl ADR 4468 from BASF.

[0162] Chain extenders can include acrylic acid-based compounds. Acrylic acid-based compounds can contain acrylic acid groups, and the acrylic acid groups can be bonded to the main chain as side chains.

[0163] Chain extenders can include isocyanate-based compounds. Isocyanate-based compounds can be at least one selected from the group consisting of monofunctional isocyanates or polyfunctional isocyanates. For example, chain extenders can be at least one selected from the group consisting of toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, diphenylmethane 4,4'-diisocyanate, 2,4'-diisocyanate, naphthalene 1,5-diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, and isophorone diisocyanate. In addition, chain extenders can include at least one selected from the group consisting of triisocyanates, tri(4-isocyanatophenyl)methane, and methylenebis(4-isocyanatocyclohexane).

[0164] The chain extender can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 1 phr to 10 phr, 1 phr to 8 phr, 1 phr to 7 phr, 1 phr to 6 phr, 2 phr to 7 phr, 3 phr to 7 phr, 1 phr to 5 phr, 1 phr to 3 phr, 1 phr to 2 phr, 0.01 phr to 3 phr, 0.05 phr to 3 phr, 0.05 phr to 2.5 phr, 0.05 phr to 1.5 phr, 0.05 phr to 1 phr, 0.1 to 1 phr, or 0.1 to 0.5 phr.

[0165] An antioxidant is an additive used to prevent decomposition by ozone or oxygen, prevent oxidation during storage, and prevent deterioration of the physical properties of a biodegradable film or biodegradable product formed from the composition for the biodegradable film.

[0166] Any commonly used antioxidant can be used as the antioxidant as long as the desired effects are not impaired.

[0167] Specifically, the antioxidant can comprise at least one selected from the group consisting of hindered phenol-based antioxidants and phosphite (phosphorus-based) antioxidants.

[0168] The hindered phenol-based antioxidant can comprise, for example, at least one selected from the group consisting of 4,4'-methylenebis(2,6-di-tert-butylphenol), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0169] The phosphite (phosphorus-based) antioxidant can comprise, for example, at least one selected from the group consisting of tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, [bis(2,4-di-tert-butyl-5-methylphenoxy)phosphino]biphenyl, and N,N-bis[2-[[2,4,8,10-tetra(1,1-dimethylethyl)dibenz[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]-ethyl]ethylamine.

[0170] The antioxidant can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 1 phr to 10 phr, 1 phr to 8 phr, 1 phr to 7 phr, 1 phr to 6 phr, 2 phr to 7 phr, 3 phr to 7 phr, 1 phr to 5 phr, 1 phr to 3 phr, 1 phr to 2 phr, 0.01 phr to 3 phr, 0.05 phr to 3 phr, 0.05 phr to 2.5 phr, 0.05 phr to 1.5 phr, 0.05 phr to 1 phr, 0.1 to 1 phr, or 0.1 to 0.5 phr.

[0171] When the content of the antioxidant meets the above ranges, the physical properties of the biodegradable film or biodegradable product formed from the composition for the biodegradable film can be enhanced, and it can be more conducive to achieving the desired effect.

[0172] The compatibilizer is an additive that imparts compatibility by eliminating the non-uniformity of the copolyhydroxyalkanoate (PHA) resin.

[0173] Any commonly used compatibilizer can be used as the compatibilizer as long as the effect is not impaired.

[0174] Specifically, the compatibilizer can include at least one selected from the group consisting of polyvinyl acetate (PVAc), isocyanate, polypropylene carbonate, glycidyl methacrylate, ethylene vinyl alcohol, polyvinyl alcohol (PVA), ethylene vinyl acetate, and maleic anhydride. The compatibilizer resin can include at least one selected from the group consisting of ethylene vinyl alcohol, polyvinyl alcohol (PVA), and ethylene vinyl acetate. For example, the compatibilizer can include Vinnex 2526 from Wacker.

[0175] The compatibilizer can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 0.1 phr to 8 phr, 0.1 phr to 7 phr, 0.1 phr to 6 phr, 0.1 phr to 5 phr, 0.1 phr to 3 phr, 0.1 phr to 2 phr, 0.5 phr to 10 phr, 0.5 phr to 8 phr, 0.5 phr to 7 phr, 0.5 phr to 6 phr, 0.5 phr to 5 phr, 0.5 phr to 3 phr, 0.5 phr to 2 phr, 0.5 phr to 1.5 phr, 0.1 to 0.5 phr, or 0.5 to 1 phr.

[0176] When the content of the compatibilizer satisfies the above range, the compatibility between the resin and the additive used increases, which can enhance the physical properties of the biodegradable film or biodegradable product formed from the composition for the biodegradable film and can be more conducive to achieving the desired effect.

[0177] The weight-increasing agent is an inorganic material and an additive, which is used to improve the moldability by increasing the crystallization rate during the molding process and to reduce the problem of increased cost caused by using biodegradable resins.

[0178] Any commonly used inorganic material can be used as the weight-increasing agent as long as the desired effect is not impaired.

[0179] Specifically, the weight-increasing agent may include at least one selected from the group consisting of calcium carbonate (such as light or heavy calcium carbonate), silica, talc, kaolin, barium sulfate, clay, calcium oxide, magnesium hydroxide, titanium oxide, carbon black, and glass fiber.

[0180] The average particle size of the weight-increasing agent can be 0.5 μm to 10 μm. If the average particle size of the weight-increasing agent is less than the above range, the particles may be difficult to disperse. If it exceeds the above range, the particle size becomes too large, which may impair the effect.

[0181] The weight-increasing agent can be used in an amount of 0.01 phr to 20 phr, 0.1 phr to 20 phr, 1 phr to 20 phr, 1 phr to 15 phr, 1 phr to 12 phr, 1 phr to 10 phr, 2 phr to 20 phr, 2 phr to 15 phr, 2 phr to 12 phr, 2 phr to 10 phr, 3 phr to 20 phr, 3 phr to 15 phr, 3 phr to 12 phr, 3 phr to 10 phr, 5 phr to 20 phr, 5 phr to 15 phr, 5 phr to 12 phr, or 5 phr to 10 phr.

[0182] When the content of the weight-increasing agent satisfies the above range, it can be more conducive to achieving the desired effect.

[0183] The nucleating agent is an additive used to supplement or change the polymer crystallization morphology and to increase the solidification rate when the polymer melt cools. In particular, the polyhydroxyalkanoate (PHA) resin used according to one embodiment has a low solidification rate, which may not be suitable for the processability of soft materials. When a nucleating agent is used, the solidification rate can be increased, further improving the processability, moldability, and productivity, and the desired physical properties can be effectively achieved.

[0184] Any general nucleating agent can be used as long as the effect is not impaired.

[0185] Specifically, the nucleating agent may be an elemental substance (pure substance), a metal compound containing a composite oxide, such as carbon black, calcium carbonate, synthetic silicate and salts, silica, zinc white, clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, diatomaceous earth, dolomite powder, titanium oxide, zinc oxide, antimony oxide, barium sulfate, calcium sulfate, alumina, calcium silicate, metal salts of organic phosphorus, and boron nitride; low molecular weight organic compounds having a metal carboxylate group, such as metal salts of the following: octanoic acid, toluic acid, heptanoic acid, nonanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, cerotic acid, montanic acid, melissic acid, benzoic acid, p-tert-butylbenzoic acid, terephthalic acid, monomethyl terephthalate, isophthalic acid, and monomethyl isophthalate; polymeric organic compounds having a metal carboxylate group, such as salts of the following: carboxyl group-containing polyethylene obtained by oxidation of polyethylene, carboxyl group-containing polypropylene obtained by oxidation of polypropylene, copolymers of acrylic acid or methacrylic acid and olefins (e.g., ethylene, propylene, and 1-butene), copolymers of acrylic acid or methacrylic acid and styrene, copolymers of olefins and maleic anhydride, and copolymers of styrene and maleic anhydride; polymeric organic compounds, such as α-olefins having 5 or more carbon atoms branched at the 3-position carbon atom (e.g., 3,3-dimethylbutene-1, 3-methylbutene-1, 3-methylpentene-1, 3-methylhexene-1, and 3,5,5-trimethylhexene-1), polymers of vinyl cycloalkanes (e.g., vinyl cyclopentane, vinyl cyclohexane, and vinyl norbornane), polyalkylene glycols (e.g., polyethylene glycol and polypropylene glycol), poly(glycolic acid), cellulose, cellulose esters, and cellulose ethers; phosphoric acid or phosphorous acid and their metal salts, such as diphenyl phosphate, diphenyl phosphite, metal salts of bis(4-tert-butylphenyl) phosphate, and metal salts of methylenebis(2,4-tert-butylphenyl) phosphate; sorbitol derivatives, such as bis(p-methylbenzylidene)sorbitol and bis(p-ethylbenzylidene)sorbitol; and thioglycolic anhydride, p-toluenesulfonic acid, and their metal salts. The nucleating agent may be used alone or in combination.

[0186] The nucleating agent can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 1 phr to 10 phr, 1 phr to 8 phr, 1 phr to 7 phr, 1 phr to 6 phr, 2 phr to 7 phr, 3 phr to 7 phr, 1 phr to 5 phr, 1 phr to 3 phr, 1 phr to 2 phr, 0.01 phr to 3 phr, 0.05 phr to 3 phr, 0.05 phr to 2.5 phr, 0.05 phr to 1.5 phr, 0.05 phr to 1 phr, 0.1 to 1 phr, or 0.1 to 0.5 phr.

[0187] When the content of the nucleating agent satisfies the above range, the solidification rate can be increased to enhance the moldability, and the productivity and processability can be further improved by increasing the solidification rate, for example, during the cutting step of producing pellets or during the preparation process.

[0188] The melt strength enhancer is an additive used to improve the melt strength of the reactants.

[0189] Any commonly used melt strength enhancer can be used as the melt strength enhancer as long as the effect is not impaired.

[0190] Specifically, the melt strength enhancer can include at least one selected from the group consisting of polyesters, styrene-based polymers (such as acrylonitrile butadiene styrene and polystyrene), polysiloxanes, organically modified silicone polymers, and maleic anhydride grafted ethylene propylene diene monomer (MAH-g-EPDM).

[0191] The melt strength enhancer can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 1 phr to 10 phr, 1 phr to 8 phr, 1 phr to 7 phr, 1 phr to 6 phr, 2 phr to 7 phr, 3 phr to 7 phr, 1 phr to 5 phr, 1 phr to 3 phr, 1 phr to 2 phr, 0.01 phr to 3 phr, 0.05 phr to 3 phr, 0.05 phr to 2.5 phr, 0.05 phr to 1.5 phr, 0.05 phr to 1 phr, 0.1 to 1 phr, or 0.1 to 0.5 phr.

[0192] When the content of the melt strength enhancer satisfies the above range, it is more conducive to achieving the desired effect.

[0193] The slip agent is an additive used to enhance the slipperiness (slip property) during the extrusion process and to prevent the surfaces of the film or sheet from sticking to each other during the process.

[0194] Any commonly used lubricant can be used as the lubricant as long as the effect is not impaired. For example, the lubricant can be at least one selected from the group consisting of erucamide, oleamide, and stearamide.

[0195] The lubricant can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 1 phr to 10 phr, 1 phr to 8 phr, 1 phr to 7 phr, 1 phr to 6 phr, 2 phr to 7 phr, 3 phr to 7 phr, 1 phr to 5 phr, 1 phr to 3 phr, 1 phr to 2 phr, 0.01 phr to 3 phr, 0.05 phr to 3 phr, 0.05 phr to 2.5 phr, 0.05 phr to 1.5 phr, 0.05 phr to 1 phr, 0.1 to 1 phr, or 0.1 to 0.5 phr.

[0196] When the content of the lubricant meets the above range, the processability, productivity, and moldability can be further improved, and it can be more conducive to achieving the desired effect.

[0197] The composition for the biodegradable film may contain a crosslinking agent and / or a stabilizer as additional additives.

[0198] The crosslinking agent is an additive used to change the properties of the polyhydroxyalkanoate (PHA) resin and increase the resin molecular weight. Any general crosslinking agent can be used as long as the effect is not impaired.

[0199] For example, the crosslinking agent can be at least one selected from the group consisting of fatty acid esters, natural oils containing epoxy groups (epoxidized), diallyl phthalate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, diethylene glycol dimethacrylate, and bis(2-methacryloyloxyethyl) phosphate.

[0200] The crosslinking agent can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 1 phr to 10 phr, 1 phr to 8 phr, 1 phr to 7 phr, 1 phr to 6 phr, 2 phr to 7 phr, 3 phr to 7 phr, 1 phr to 5 phr, 1 phr to 3 phr, 1 phr to 2 phr, 0.01 phr to 3 phr, 0.05 phr to 3 phr, 0.05 phr to 2.5 phr, 0.05 phr to 1.5 phr, 0.05 phr to 1 phr, 0.1 to 1 phr, or 0.1 to 0.5 phr.

[0201] A stabilizer is an additive used to prevent oxidation, heat, and color change. Any commonly used stabilizer can be used as the stabilizer as long as the effect is not impaired.

[0202] Specifically, the stabilizer can be one selected from the group consisting of trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, and phosphorous acid.

[0203] The stabilizer can be used in an amount of 0.01 phr to 10 phr, 0.1 phr to 10 phr, 1 phr to 10 phr, 1 phr to 8 phr, 1 phr to 7 phr, 1 phr to 6 phr, 2 phr to 7 phr, 3 phr to 7 phr, 1 phr to 5 phr, 1 phr to 3 phr, 1 phr to 2 phr, 0.01 phr to 3 phr, 0.05 phr to 3 phr, 0.05 phr to 2.5 phr, 0.05 phr to 1.5 phr, 0.05 phr to 1 phr, 0.1 to 1 phr, or 0.1 to 0.5 phr.

[0204] Meanwhile, the composition for the biodegradable film may further contain a carrier resin.

[0205] The carrier resin can be in the form of a masterbatch capable of carrying or transporting functional additives.

[0206] For example, the carrier resin may include a resin based on poly(butylene adipate-co-terephthalate) (PBAT). Specifically, it may include a masterbatch containing a resin based on poly(butylene adipate-co-terephthalate) (PBAT).

[0207] Although the carrier resin has poor dispersibility, since it carries or transports the additives for imparting functions to the composition or the film, it can effectively impart the desired functions without side effects caused by using functional additives with poor dispersibility, and it can maintain excellent biodegradability and mechanical properties.

[0208] The carrier resin, such as a resin based on poly(butylene adipate-co-terephthalate) (PBAT), may have a weight-average molecular weight (Mw) of about 100,000 to 500,000 g / mol, about 120,000 to 500,000 g / mol, about 150,000 to 450,000 g / mol, about 150,000 to 430,000 g / mol, or about 150,000 to 400,000 g / mol. The weight-average molecular weight (Mw) can be measured by gel permeation chromatography (GPC).

[0209] Resins based on poly(butylene adipate terephthalate) (PBAT) are aliphatic-aromatic polyester copolymers and can be obtained by polycondensation of 1,4-butanediol, adipic acid and terephthalic acid or dimethyl terephthalate according to known methods.

[0210] According to one embodiment, the content of the carrier resin can be 1 phr to 100 phr, 5 phr to 100 phr, 5 phr to 80 phr, 10 phr to 60 phr, 10 phr to 50 phr, 10 phr to 40 phr, 10 phr to 30 phr, 15 phr to 40 phr, 15 phr to 35 phr, 15 phr to 30 phr, 15 phr to 25 phr, 18 phr to 35 phr, 18 phr to 30 phr, 18 phr to 25 phr, 20 phr to 30 phr, 20 phr to 25 phr, or 10 phr to 20 phr. When the content of the carrier resin meets the above range, the desired functions can be effectively imparted without side effects.

[0211] Physical properties of the composition for biodegradable film

[0212] According to one embodiment, since the composition for the biodegradable film has a melt index that is very favorable for achieving excellent processability and productivity, the processability and productivity can be improved simultaneously during film forming, and biodegradable films and biodegradable products with enhanced biodegradability, optical properties and mechanical properties can be provided. In particular, when preparing a biodegradable film or a final biodegradable product, the load applied to the molding equipment can be minimized and the quality of the product can be further improved.

[0213] First, when the composition for the biodegradable film is fed into an extruder equipped with a screw at 6 rpm and extruded at a screw speed of 200 rpm at 170 °C, the load (torque) applied to the screw can be 70% or less at a pressure of 46 bar or less in the extruder.

[0214] When the composition for the biodegradable film is extrusion molded, the load applied to the screw can be significantly reduced, thereby improving productivity, processability and moldability.

[0215] Specifically, at a pressure of 46 bar or less in the extruder, the load (torque) applied to the screw can be less than 70%, 65% or less, 60% or less, less than 60%, 59% or less, or 58% or less.

[0216] According to one embodiment, at a pressure of 46 bar or less in the extruder, the load (torque) applied to the screw can be 60% or less, less than 60%, 59% or less, 58% or less, 55% or less, or 54% or less.

[0217] According to another embodiment, at a pressure of 40 bar to 46 bar in the extruder, the load (torque) applied to the screw can be 40% to less than 70%, 40% to 65%, 45% to 60%, 48% to 60%, 50% to 60%, 52% to 60%, 53% to 60%, or 55% to 60%.

[0218] According to another embodiment, at a pressure greater than 35 bar and less than 40 bar in the extruder, the load (torque) applied to the screw can be 40% to less than 70%, 40% to 65%, 45% to 65%, 50% to 65%, 50% to 63%, 52% to 63%, 53% to 62%, or 55% to 60%.

[0219] In addition, at a pressure of 30 bar to 35 bar in the extruder, the load (torque) applied to the screw can be 40% to 60%, 42% to 60%, 45% to 60%, 48% to 60%, 50% to 60%, 52% to less than 60%, 53% to 58%, or 53% to 55%.

[0220] In addition, at a pressure of 25 bar to less than 30 bar in the extruder, the load (torque) applied to the screw can be 40% to 60%, 42% to 60%, 45% to 60%, 48% to 60%, 50% to less than 60%, 50% to 58%, or 50% to 55%.

[0221] In an extruder equipped with a screw, the ratio of the length (L) to the diameter (D) of the screw (L / D) can be 20 to 50, and the diameter (D) of the screw can be to For example, in an extruder equipped with a screw, the ratio of the length (L) to the diameter (D) of the screw (L / D) can be 40, and the diameter (D) of the screw can be However, they are not limited thereto.

[0222] In addition, the load applied to the screw and the pressure value can vary according to the type of extruder.

[0223] In addition, in one embodiment, the composition for the biodegradable film can have physical properties suitable for various molding processes such as extrusion molding, injection molding, compression molding, pneumatic molding, blow molding or blow molding, and thermoforming.

[0224] For example, a composition for a biodegradable film can have physical properties suitable for extrusion molding. Thus, a composition for a biodegradable film can be a composition for a biodegradable extruded film for extrusion molding.

[0225] [Biodegradable film]

[0226] In one embodiment, a biodegradable film comprising a composition for a biodegradable film is provided.

[0227] The biodegradable film can be biodegraded by any one of microorganisms, moisture, oxygen, light, and heat, and has excellent mechanical properties.

[0228] Specifically, the tensile strength of the biodegradable film can be 10 MPa to 50 MPa, 15 MPa to 45 MPa, 15 MPa to 40 MPa, 20 MPa to 40 MPa, 20 MPa to 35 MPa, or 20 MPa to 30 MPa.

[0229] To measure the tensile strength, the biodegradable film is cut into 10 cm in length and 1 cm in width according to ASTM D882 and mounted on a universal testing machine (UTM) with a chuck spacing of 20 mm. The test is carried out at a tensile speed of 200 mm / min at a room temperature of 25 °C, and the tensile strength is measured with a program installed in the equipment. When the tensile strength meets the above range, the mechanical properties, productivity, processability, and moldability of the biodegradable film can be improved simultaneously, and it can be more beneficial to achieve the desired effect.

[0230] In addition, the elongation at break of the biodegradable film can be 200% or greater, 250% or greater, 270% or greater, 280% or greater, 290% or greater, or 295% or greater, and 900% or less, 800% or less, 700% or less, 600% or less, 500% or less, 480% or less, or 450% or less.

[0231] For example, the elongation at break of the biodegradable film can be 200% to 900%, 200% to 800%, 250% to 600%, 250% to 500%, 250% to 480%, 250% to 450%, 280% to 450%, or 290% to 450%.

[0232] According to one embodiment, the tensile strength of the biodegradable film is 10 MPa to 50 MPa, and the elongation at break is 200% or greater.

[0233] To measure the elongation at break, the biodegradable film was cut into dimensions of 10 cm in length and 1 cm in width according to ASTM D882 and mounted on a universal testing machine (UTM) with a chuck spacing of 20 mm. The maximum deformation at the point of fracture was measured at a tensile speed of 200 mm / min. The ratio of the maximum deformation to the initial length was calculated as the elongation at break.

[0234] Meanwhile, the biodegradable film can have excellent optical properties.

[0235] Specifically, the haze of the biodegradable film can be 95% or less, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, or 5% or less. If the haze exceeds the above range, the transparency of the biodegradable film is significantly reduced, which may limit its use for packaging purposes, for example, where the contents inside are visible.

[0236] The biodegradable film is characterized by excellent mechanical properties and a biodegradability of 90% or higher in soil and the ocean.

[0237] Biodegradability refers to the decomposition rate relative to a standard material (e.g., cellulose) over the same time. The Ministry of Environment of Korea defines biodegradable materials as those having a biodegradability of 90% or higher relative to the standard material. Specifically, the marine biodegradability measured according to the EL724 standard is 90% or higher.

[0238] The biodegradable film can include a biodegradable extruded film prepared by extrusion molding a composition for the biodegradable film.

[0239] [Method for preparing a biodegradable film]

[0240] In one embodiment, a method for preparing a biodegradable film using a composition for the biodegradable film is provided.

[0241] Specifically, the method for preparing a biodegradable film can include a first step of preparing a composition for the biodegradable film; and a second step of feeding the composition into an extruder and extruding and molding it.

[0242] Hereinafter, the method for preparing a biodegradable film will be described in detail.

[0243] First, the method for preparing a biodegradable film includes a first step of preparing a composition for the biodegradable film.

[0244] Specifically, the first step may include mixing a polyhydroxyalkanoate (PHA) resin with a plasticizer having a melting temperature of 95°C to 250°C.

[0245] The polyhydroxyalkanoate (PHA) resin and the plasticizer are as described above.

[0246] The composition for a biodegradable film may use the polyhydroxyalkanoate (PHA) resin alone as the main resin, or it may contain a mixed resin in which the polyhydroxyalkanoate (PHA) resin is mixed with the above-mentioned biodegradable resin.

[0247] For example, the composition for a biodegradable film may contain a polyhydroxyalkanoate (PHA) resin and a polylactic acid (PLA) resin.

[0248] In addition, the composition for a biodegradable film can be prepared by adding a plasticizer having a melting temperature within the above specific range to the mixed resin.

[0249] In addition, the composition for a biodegradable film can be prepared by adding a plasticizer having a melting temperature within the above specific range and the above additives to the mixed resin. In this case, the additives can be selected and used in various ways according to the intended use and desired effects, but they are not limited thereto.

[0250] For example, the composition for a biodegradable film can be prepared by mixing a mixed resin of a polyhydroxyalkanoate (PHA) resin and a polylactic acid (PLA) resin as the main resin, a plasticizer, a chain extender, a compatibilizer, and a weight-increasing agent as additives.

[0251] The types and contents of the respective components contained in the main resin and the additives are as described above.

[0252] In addition, the composition for a biodegradable film may further contain a carrier resin capable of carrying or transporting the above additives and / or functional additives.

[0253] That is, the first step may include adding a carrier resin to the polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature of 95°C to 250°C. The carrier resin may include a resin based on polybutylene adipate terephthalate (PBAT). Specifically, it may include a masterbatch based on polybutylene adipate terephthalate (PBAT). The type and content of the carrier resin are as described above.

[0254] Meanwhile, the method for preparing a biodegradable film includes a second step of feeding the composition for a biodegradable film into an extruder and extruding and molding it.

[0255] The composition for a biodegradable film according to one embodiment can be extrusion molded into a shape suitable for the intended use. For example, the composition for a biodegradable film can be provided in the form of pellets and then extrusion molded to prepare a biodegradable film, or the composition for a biodegradable film can be directly extrusion molded to prepare a biodegradable film.

[0256] Molding can be carried out using extrusion molding.

[0257] A single-screw extruder or a twin-screw extruder can be used as the extruder.

[0258] The extruder can be a T-die twin-screw extruder equipped with a screw.

[0259] Figure 1 is a partial cross-sectional view of the extruder used according to one embodiment. Refer to Figure 1 , the extruder (100) can include a raw material feeder (110), a compression section (120), a screw (130), a head (140), and a die (150).

[0260] The extrusion molding conditions can vary according to the use of the biodegradable film, and the extrusion can be carried out by a commonly used method.

[0261] The composition for a biodegradable film can be fed to the raw material feeder (110) of the extruder (100) at a speed of, for example, 2 rpm to 50 rpm, 2 rpm to 40 rpm, 2 rpm to 30 rpm, or 2 rpm to 20 rpm.

[0262] The rotational speed of the screw (130) of the extruder (100) can be, for example, 100 rpm to 300 rpm, 120 rpm to 280 rpm, 150 rpm to 250 rpm, or 180 rpm to 230 rpm.

[0263] The extrusion temperature can be 100°C to 210°C, 120°C to 200°C, 120°C to 180°C, 120°C to 175°C, 130°C to 175°C, or, for example, 140°C to 175°C.

[0264] For example, based on the temperature measured at the die (150) of the extruder (100), the extrusion temperature can be 100°C to 210°C, 120°C to 200°C, 120°C to 180°C, 120°C to 175°C, 150°C to 180°C, 150°C to 175°C, 160°C to 180°C, or 160°C to 170°C.

[0265] Based on the temperature measured at the head (die head) (140) of the extruder (100), the extrusion temperature can be 100°C to 210°C, 120°C to 200°C, 120°C to 180°C, 120°C to 175°C, 150°C to 200°C, 150°C to 180°C, or 155°C to 175°C.

[0266] When the extrusion molding conditions satisfy the above ranges, it can be more conducive to achieving the desired effects.

[0267] In addition, the load and pressure values applied to the screw can vary according to the type of extruder.

[0268] In addition, according to one embodiment, before feeding the composition for the biodegradable film into the die head of the extruder, a preheating step (preheating step) can also be carried out.

[0269] The preheating step can be carried out, for example, at 110°C to 170°C. Specifically, the preheating step can be carried out by gradually increasing the temperature through a given temperature gradient (for example, starting from 110°C to 130°C to 150°C to 170°C).

[0270] According to one embodiment, the extrusion pressure can be 46 bar or less, 45 bar or less, 44 bar or less, 43 bar or less, 42 bar or less, 40 bar or less, or less than 40 bar. For example, 20 bar to 46 bar, 25 bar to 46 bar, 20 bar to 45 bar, 25 bar to 45 bar, 28 bar to 46 bar, 28 bar to 45 bar, 40 bar to 46 bar, greater than 35 bar to less than 40 bar, 30 bar to 35 bar. Herein, the extrusion pressure can be, for example, the pressure at the head (die head) (140) inside the extruder (100).

[0271] When the extrusion pressure satisfies the above ranges, the load (torque) applied to the molding equipment, especially the screw, during the extrusion molding process can be minimized, the processability and productivity can be improved simultaneously, and the quality of the final product can be further improved.

[0272] In addition, the method for preparing the biodegradable film can further include, after molding, heat treatment (heat setting) and / or drying. The process conditions used in the art can be used as the process conditions for these steps as long as the desired effects are not impaired.

[0273] In addition, according to one embodiment, a biodegradable product is provided, which comprises a biodegradable film or a composition for a biodegradable film.

[0274] The biodegradable product can include at least one selected from the group consisting of primary and secondary packaging materials for food, electronic products or hygiene products, straws, trays, edible containers, and adhesive products.

[0275] Embodiments of the present invention

[0276] The present disclosure will be described in more detail below with reference to the following examples. However, the following examples are intended to illustrate the present disclosure, and the scope of the examples is not limited thereto.

[0277] <Examples>

[0278] Example 1

[0279] As shown in Table 1 below, a mixed resin of polyhydroxyalkanoate (PHA) resin (3-HB-co-4-HB, aPHA, 4-HB content: 34 mol%) (CJ Corporation) and polylactic acid (PLA) resin (Natureworks, 4032D) with a weight ratio of 40:60, polybutylene adipate terephthalate (PBAT) (Ankor bioplastics) as a carrier resin, and Vinnex 2526 (compatibilizer, Wacker), Joncryl ADR 4468 (chain extender, BASF), adipic acid (plasticizer, BASF), and calcium carbonate (CaCO3) (weight increasing agent, Junsei Chemical) as additives were mixed to prepare a composition for a biodegradable film.

[0280] The composition for the biodegradable film was fed into a T-die twin-screw extruder (BA-19, Bautek), and T-die extrusion molding was carried out under the process conditions of temperature and speed shown in Table 2 below to prepare a biodegradable film.

[0281] Examples 2 to 4

[0282] The composition for the biodegradable film and the biodegradable film were prepared in the same manner as in Example 1, except that the content of adipic acid was changed as shown in Table 1 below.

[0283] Examples 5 to 7

[0284] The composition for the biodegradable film and the biodegradable film were prepared in the same manner as in Example 1, except that the mixing weight ratio of polyhydroxyalkanoate (PHA) and polylactic acid (PLA) resins and the content of adipic acid were changed as shown in Table 1 below.

[0285] <Evaluation Examples>

[0286] Evaluation Example 1: Tensile strength

[0287] The biodegradable films prepared from the respective compositions for biodegradable films were cut into samples 10 cm long and 1 cm wide according to ASTM D882 and mounted on a universal testing machine (4206 - 001, manufacturer: UTM) with a chuck spacing of 20 mm. The test was carried out at a tensile speed of 200 mm / min at room temperature of 25 °C, and the tensile strength was measured using a program installed in the equipment.

[0288] Evaluation Example 2: Elongation at break

[0289] The biodegradable films prepared from the respective compositions for biodegradable films were cut into samples 10 cm long and 1 cm wide according to ASTM D882 and mounted on a universal testing machine (4206 - 001, manufacturer: UTM). The test was carried out at a tensile speed of 200 mm / min to measure the maximum deformation at the point of rupture. The ratio of the maximum deformation to the initial length was calculated as the elongation at break.

[0290] Evaluation Example 3: Processability

[0291] The processability of each composition for biodegradable films was determined by the pressure level (bar) of the extruder head and the load applied to the motor (torque, %) when using the extruder. The load level applied to the motor was evaluated using a measuring device placed inside the equipment.

[0292] The specific compositions, mechanical properties, and melt indices of the respective compositions for biodegradable films obtained in the examples are summarized in Table 1 below, and the process conditions during extrusion molding and the results of the processability evaluation are summarized in Table 2 below.

[0293] [Table 1]

[0294]

[0295]

[0296] *Phr (parts per hundred resin) is a unit, which refers to the input amount of the material added per 100 weight parts of the polymer resin (1 phr: when the polymer resin is 100 g, the input amount of 1 g of additive).

[0297] [Table 2]

[0298]

[0299] As can be seen from Table 2 above, in the compositions for biodegradable films prepared in Examples 1 to 7, at a pressure of 46 bar or lower in the extruder, the load (torque) applied to the screw was at a low level of about 53% to about 60%, and the biodegradable films prepared from the respective compositions for biodegradable films had a tensile strength of about 20 MPa or higher and an elongation at break of about 295.4% or higher, indicating excellent processability and mechanical properties.

[0300] Specifically, in the compositions for biodegradable films prepared in Examples 1 to 3, where the weight ratio of polylactic acid (PLA) to polyhydroxyalkanoate (PHA) was 60:40, as the content of the plasticizer increased from 0.1 phr to 0.5 phr, the pressure in the extruder decreased from about 40 bar to about 34 bar, and the load (torque) applied to the screw decreased from 60% to 55%. The biodegradable films prepared from the respective compositions for biodegradable films showed excellent mechanical properties, with a tensile strength of about 26.7 MPa to about 27.3 MPa and an elongation at break of about 370.2% to about 440.7%.

[0301] In addition, in the compositions for biodegradable films prepared in Examples 5 and 6, where the weight ratio of PLA to PHA was 70:30, as the content of the plasticizer increased from 0.1 phr to 0.3 phr, the pressure in the extruder decreased from about 46 bar to about 44 bar, and the load (torque) applied to the screw decreased from about 60% to about 55%. The biodegradable films prepared from the respective compositions for biodegradable films showed excellent mechanical properties, with a tensile strength of about 28.0 MPa to about 29.5 MPa and an elongation at break of about 295.4% to about 345.6%.

[0302] In addition, the compositions for biodegradable films prepared in Examples 1 - 7 contain a biodegradable resin and environmentally friendly adipic acid as an additive; thus, they have excellent biodegradability and are highly desirable from an environmental-friendly perspective, so they can be applied to various fields.

Claims

1. A composition for a biodegradable film, comprising a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature of 95°C to 250°C, wherein when the composition for a biodegradable film is fed into an extruder equipped with a screw at 6 rpm and extruded at a screw speed of 200 rpm at 170°C, the load (torque) applied to the screw is 70% or less at a pressure of 46 bar or less in the extruder.

2. The composition for a biodegradable film according to claim 1, wherein the content of the plasticizer is 0.01 phr to 10 phr.

3. The composition for a biodegradable film according to claim 1, wherein the plasticizer is adipic acid.

4. The composition for a biodegradable film according to claim 1, wherein the polyhydroxyalkanoate (PHA) resin satisfies at least one of the following properties: a glass transition temperature (Tg) of -45°C to 80°C, a crystallization temperature (Tc) of 60°C to 120°C, and a melting temperature (Tm) of 100°C to 170°C.

5. The composition for a biodegradable film according to claim 1, wherein the polyhydroxyalkanoate (PHA) resin comprises at least one monomer selected from the group consisting of 4-hydroxybutyrate (4-HB), 3-hydroxybutyrate (3-HB), 3-hydroxypropionate (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

6. The composition for a biodegradable film according to claim 5, wherein the polyhydroxyalkanoate (PHA) resin comprises a polyhydroxyalkanoate (PHA) copolymer (PHA copolymer) containing 4-hydroxybutyrate (4-HB) monomers, and the 4-hydroxybutyrate (4-HB) monomers are used in an amount of 1 mol% to 99 mol% based on the total number of moles of monomers contained in the polyhydroxyalkanoate (PHA) copolymer.

7. The composition for a biodegradable film according to claim 6, wherein the polyhydroxyalkanoate (PHA) resin comprises a resin containing 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers, and the 4-hydroxybutyrate (4-HB) monomers are used in an amount of 1 mol% to 60 mol% based on the total number of moles of 3-hydroxybutyrate (3-HB) monomers and 4-hydroxybutyrate (4-HB) monomers.

8. The composition for a biodegradable film according to claim 1, further comprising at least one biodegradable resin selected from the group consisting of: polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene adipate (PBA), polybutylene succinate adipate (PBSA), polybutylene succinate terephthalate (PBST), polyhydroxybutyrate valerate (PHBV), polycaprolactone (PCL), polybutylene succinate adipate terephthalate (PBSAT), and thermoplastic starch (TPS).

9. The composition for a biodegradable film according to claim 8, further comprising a polylactic acid (PLA) resin, wherein the weight ratio of the polyhydroxyalkanoate (PHA) resin to the polylactic acid (PLA) resin is from 10:90 to 50:

50.

10. The composition for a biodegradable film according to claim 1, further comprising at least one additive selected from the group consisting of: chain extender, antioxidant, compatibilizer, weight increasing agent, nucleating agent, melt strength enhancer, and slip agent, wherein the content of the additive is from 0.1 phr to 50 phr.

11. A biodegradable film comprising the composition for a biodegradable film according to claim 1.

12. The biodegradable film according to claim 11, having a tensile strength of from 10 MPa to 50 MPa and an elongation at break of 200% or more.

13. A method for preparing a biodegradable film, comprising: a first step of preparing the composition for a biodegradable film according to claim 1; and a second step of feeding the composition for a biodegradable film into an extruder for extrusion molding thereof.

14. The method for preparing a biodegradable film according to claim 13, wherein the first step comprises mixing a polyhydroxyalkanoate (PHA) resin with a plasticizer having a melting temperature of from 95°C to 250°C.

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