Composition for biodegradable film, biodegradable film containing the same, and method for producing biodegradable film

Abstract

One embodiment of the composition for biodegradable films contains a polyhydroxyalkanoate (PHA) resin and a plasticizer with a melting temperature within a specific range. This allows the pressure inside the extruder during extrusion molding to be 46 bar or less and the torque applied to the screw to be 70% or less, improving both processability and productivity, and providing eco-friendly biodegradable films and products with excellent biodegradability and mechanical properties.

Description

[Technical Field]

[0001] Embodiments relate to a composition for a biodegradable film, a biodegradable film including the same, and a method for preparing the biodegradable film. [Background technology]

[0002] Currently available general-purpose plastics on the market have excellent physical properties and are in high demand due to their stable supply and low price. However, the disposal of waste plastics is becoming a serious problem in all aspects of our lives. Because waste plastics do not decompose under natural conditions, such as in the ocean or soil, they are a cause of serious environmental pollution. In order to solve these environmental pollution problems, active research into biodegradable plastics has been conducted in recent years.

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

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

[0005] Generally, many of the additives that have been used until now are petroleum-based products. Most of these do not meet the objective of developing environmentally friendly materials. Therefore, in pursuit of 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 to providing high-quality biodegradable films and products that use naturally derived additives and that combine environmentally friendly properties with mechanical properties such as strength and elongation. From the perspective of processing, using molding equipment places a heavy load on the equipment, and there are limitations to ensuring good processability and productivity in various processes such as extrusion molding. [Prior art documents] [Patent documents]

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

[0008] The present disclosure has been made to solve the above-mentioned problems of the prior art.

[0009] According to one embodiment, the present disclosure aims to provide a composition for a biodegradable film that has excellent mechanical properties such as tensile strength and elongation, improves processability and productivity during molding, and is biodegradable in both soil and the ocean, making it environmentally friendly.

[0010] According to one embodiment, the present disclosure aims to provide a biodegradable film formed from a biodegradable film composition and a method for preparing the same. [Means for solving the problem]

[0011] In one embodiment to achieve the above object, there is provided a composition for biodegradable films, which comprises a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature of 95°C to 250°C, and when the composition for biodegradable films is fed into an extruder equipped with a 6 rpm screw and extruded at a screw rotation speed of 200 rpm and 170°C, the pressure inside the extruder is 46 bar or less and the load (torque) on the screw is 70% or less.

[0012] In another embodiment of the composition for biodegradable films, the content of the plasticizer is 0.01 phr to 10 phr.

[0013] In another embodiment of the biodegradable film composition, the plasticizer is adipic acid.

[0014] In another embodiment of the composition for biodegradable films, 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.

[0015] In another embodiment of the biodegradable film composition, the polyhydroxyalkanoate (PHA) resin comprises at least one monomer selected from the group consisting of 4-hydroxybutyric acid (4-HB), 3-hydroxybutyric acid (3-HB), 3-hydroxypropionic acid (3-HP), 3-hydroxyvalerate (3-HV), 3-hydroxyhexanoate (3-HH), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

[0016] In another embodiment of the biodegradable film composition, the polyhydroxyalkanoate (PHA) resin comprises a polyhydroxyalkanoate (PHA) copolymer (PHA copolymer) containing 4-hydroxybutyric acid (4-HB) monomer, and the 4-hydroxybutyric acid (4-HB) monomer is 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.

[0017] In another embodiment of the biodegradable film composition, the polyhydroxyalkanoate (PHA) resin comprises a resin containing 3-hydroxybutyric acid (3-HB) monomers and 4-hydroxybutyric acid (4-HB) monomers, and the 4-hydroxybutyric acid (4-HB) monomers are used in an amount of 1 mol % to 60 mol % based on the total number of moles of the 3-hydroxybutyric acid (3-HB) monomers and the 4-hydroxybutyric acid (4-HB) monomers.

[0018] In another embodiment, the composition for a biodegradable film 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).

[0019] In another embodiment, the composition for a biodegradable film further contains a polylactic acid (PLA) resin, and the weight ratio of the polyhydroxyalkanoate (PHA) resin to the polylactic acid (PLA) resin is 10:90 to 50:50.

[0020] In another embodiment, the composition for biodegradable films further comprises at least one additive selected from the group consisting of a chain extender, an antioxidant, a compatibilizer, a weighting agent, a nucleating agent, a melt strength enhancer, and a lubricant, and the content of the additive is 0.1 phr to 50 phr.

[0021] In another embodiment, a biodegradable film is provided that includes the biodegradable film composition.

[0022] In another embodiment, the biodegradable film has a tensile strength of 10 MPa to 50 MPa and an elongation of 200% or more.

[0023] In another embodiment, there is provided a method for preparing a biodegradable film, the method comprising: a first step of preparing a composition for a biodegradable film; and a second step of feeding the composition for a biodegradable film into an extruder and extruding the composition.

[0024] In another embodiment of the method for preparing a biodegradable film, the first step includes mixing a polyhydroxyalkanoate (PHA) resin with a plasticizer having a melting temperature of 95°C to 250°C. [Effects of the Invention]

[0025] A composition for a biodegradable film according to one embodiment includes a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature within a specific range, and when the composition for a biodegradable film is extruded through an extruder, the pressure inside the extruder is 46 bar or less and the load (torque) on the screw is 70% or less. This improves both processability and productivity, and makes it possible to provide environmentally friendly biodegradable films and biodegradable products with excellent biodegradability and mechanical properties. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a partial cross-sectional view of an extruder used in accordance with one embodiment.

[0027] Explanation of symbols 100 Extruder 110 Raw material supply equipment 120 Compression section 130 Screw 140 Head (Header) 150 Dies DETAILED DESCRIPTION OF THE INVENTION

[0028] The present disclosure will be described in detail below with reference to the drawings of the embodiments. The embodiments are not limited to the following embodiments. Rather, the embodiments can be modified in various ways without departing from the spirit of the present invention.

[0029] In this specification, when a part is described as "comprising" an element, it does not mean that the part excludes other elements, but that the part may include other elements, unless otherwise specified.

[0030] Furthermore, unless otherwise specified, all numerical values ​​used herein that represent the physical properties, dimensions, etc. of elements are within the scope of understanding even if modified by the term "approximately."

[0031] In this specification, terms such as first, second, etc. are used in describing various components. However, these components should not be bound by these terms. These terms are used simply to distinguish one component from another.

[0032] Biodegradable film composition According to one embodiment, a composition for a biodegradable film is provided, which comprises a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature of 95°C to 250°C, and when the composition for a biodegradable film is fed into an extruder equipped with a screw at 6 rpm and extruded at a screw rotation speed of 200 rpm at 170°C, the pressure inside the extruder is 46 bar or less and the load (torque) on the screw is 70% or less.

[0033] According to one embodiment, the composition for biodegradable films contains a polyhydroxyalkanoate (PHA) resin and a plasticizer with a melting temperature within a specific range, thereby making it possible to provide environmentally friendly biodegradable films and biodegradable products with excellent biodegradability and mechanical properties. In addition, the fluidity of the entire resin contained in the composition for biodegradable films is improved at molding temperatures, and the melt index of the composition for biodegradable films is improved, so that the load (torque) on the screw at a pressure of 46 bar or less inside the extruder during extrusion molding is 70% or less. This is technically significant as it allows for a significant reduction in the load on the screw during extrusion molding (for example, when using extrusion equipment (extruder)), while at the same time improving processability and productivity and further improving the quality of the final product.

[0034] Each component of the composition for biodegradable films will be described in detail below.

[0035] Polyhydroxyalkanoate (PHA) resin A composition for a biodegradable film according to one embodiment of the present disclosure includes polyhydroxyalkanoate (PHA).

[0036] By including a polyhydroxyalkanoate (PHA) resin in the composition for biodegradable films, it is possible to improve biodegradability and mechanical properties such as tensile strength and elongation, and when molding the composition for biodegradable films, it is possible to simultaneously improve processability and productivity, and further to improve the quality of the biodegradable film and biodegradable products prepared therefrom.

[0037] Polyhydroxyalkanoates (PHAs) have similar physical properties to conventional petroleum-derived synthetic polymers such as polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), and polybutylene succinate adipate (PBSA), and are completely biodegradable and have excellent biocompatibility.

[0038] Specifically, polyhydroxyalkanoates (PHAs) are natural thermoplastic polyester polymers that accumulate within microbial cells. Because they are biodegradable, they can be composted and ultimately decompose into carbon dioxide, water, and organic waste without producing harmful waste. In particular, polyhydroxyalkanoates (PHAs) are biodegradable in soil and the ocean, making them environmentally friendly.

[0039] The polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) homopolymer consisting of one type of monomer, or a polyhydroxyalkanoate (PHA) copolymer containing two or more different types of monomers, or may include a polyhydroxyalkanoate (PHA) homopolymer and a polyhydroxyalkanoate (PHA) copolymer.

[0040] When the polyhydroxyalkanoate (PHA) is a copolymer, it may be, for example, a copolymerized polyhydroxyalkanoate (PHA) containing two or more different repeating units in which different monomers are randomly arranged within the polymer chain.

[0041] Monomers that may be contained in polyhydroxyalkanoates (PHAs) include, for example, 2-hydroxybutyrate, lactic acid, glycolic acid, 3-hydroxybutyric acid (hereinafter referred to as 3-HB), 3-hydroxypropionic acid (hereinafter referred to as 3-HP), 3-hydroxyvalerate (hereinafter referred to as 3-HV), 3-hydroxyhexanoate (hereinafter referred to as 3-HH), 3-hydroxyheptanoate (hereinafter referred to as 3-HHep), 3-hydroxyoctanoate (hereinafter referred to as 3-HHep), and 3-hydroxybutanoate (hereinafter referred to as 3-HV). Examples of polyhydroxyalkanoates include 3-hydroxybutyrate (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) may contain at least one monomer selected from the above.

[0042] The polyhydroxyalkanoate (PHA) resin may contain 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.

[0043] For example, the polyhydroxyalkanoate (PHA) may include a polyhydroxyalkanoate (PHA) homopolymer consisting of a monomer 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.

[0044] Specifically, the polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) homopolymer consisting of a monomer selected from the group consisting of 4-HB and 3-HB, or may be a polyhydroxyalkanoate (PHA) copolymer containing at least one monomer selected from the group consisting of 4-HB and 3-HB.

[0045] More specifically, the polyhydroxyalkanoate (PHA) may include 4-HB monomers.

[0046] The polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) homopolymer made from 4-HB monomers.

[0047] The polyhydroxyalkanoate (PHA) may also include a polyhydroxyalkanoate (PHA) copolymer containing 4-HB monomers.

[0048] For example, the polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) copolymer that contains 4-HB monomers and one other monomer that is different from the 4-HB monomer, or that contains two, three, four, five, six, or more different monomers.

[0049] According to one embodiment, the polyhydroxyalkanoate (PHA) may comprise a 4-HB monomer 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, the polyhydroxyalkanoate (PHA) may comprise a polyhydroxyalkanoate (PHA) copolymer comprising a 3-HB monomer and a 4-HB monomer.

[0050] For example, the polyhydroxyalkanoate (PHA) may be poly-3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter referred to as 3HB-co-4HB).

[0051] Furthermore, polyhydroxyalkanoates (PHAs) may contain isomers. For example, polyhydroxyalkanoates (PHAs) may contain structural isomers, enantiomers, or geometric isomers. Specifically, polyhydroxyalkanoates (PHAs) may contain structural isomers.

[0052] In one embodiment, polyhydroxyalkanoates (PHAs) containing 4-HB monomers are particularly suitable for use in biodegradable films and products, and can be used to achieve the desired excellent mechanical properties, as well as processability and productivity in molding processes. In such cases, controlling the content ratio of 4-HB monomer can be important.

[0053] For example, the polyhydroxyalkanoate (PHA) can include a polyhydroxyalkanoate copolymer (PHA copolymer) containing 4-HB monomers, and the polyhydroxyalkanoate (PHA) may include 4-hydroxybutyric acid (4-HB) monomers in an amount of 1 mol % to 99 mol % based on the total number of moles of monomers contained in the polyhydroxyalkanoate (PHA) copolymer.

[0054] Specifically, the polyhydroxyalkanoate (PHA) can include a polyhydroxyalkanoate (PHA) copolymer containing 3-HB and 4-HB monomers, and the polyhydroxyalkanoate (PHA) copolymer may contain 4-hydroxybutyric acid (4-HB) monomers in an amount of 1 mol % to 99 mol % based on the total number of moles of the 3-hydroxybutyric acid (3-HB) and 4-hydroxybutyric acid (4-HB) monomers.

[0055] For example, the polyhydroxyalkanoate (PHA) copolymer may contain 4-hydroxybutyric acid (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 may contain 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 moles of 3-hydroxybutyric acid (3-HB) monomers and 4-hydroxybutyric acid (4-HB) monomers.

[0056] Specifically, the polyhydroxyalkanoate (PHA) copolymer contains 1 mol% to 99 mol%, 1 mol% to 95 mol%, 1 mol% to 90 mol%, 1 mol% to 89 mol%, 1 mol% to 85 mol%, 1 mol% to 80 mol%, 1 mol% to 79 mol%, 1 mol% to 75 mol%, 1 mol% to 70 mol%, 1 mol% to 65 mol%, 1 mol% to 60 mol%, 1 mol% to 55 mol%, 1 mol% to 50 mol%, 2 mol% to 55 mol%, 3 mol% to 55 mol%, 3 mol% to 50 mol%, 5 mol% to 55 mol%, 5 mol% to 50 mol%, 10 mol% to 55 mol%, 10 mol% to 50 mol%, 15 mol% to 60 mol%, 15 mol% to 55 mol%, 15 mol% to 50 mol%, 20 mol% to 60 mol%, 20 mol% to 55 mol%, 20 mol% to 50 mol%, 25 mol% to 60 mol%, 25 mol% to 55 mol%, 25 mol% to 50 mol%, 25 mol% to 45 mol%, 25 mol% to 4 It may be contained in an amount of 0 mol%, 30 mol% to 60 mol%, 30 mol% to 55 mol%, 30 mol% to 50 mol%, 30 mol% to 45 mol%, 30 mol% to 40 mol%, 35 mol% to 60 mol%, 35 mol% to 55 mol%, 35 mol% to 50 mol%, 40 mol% to 60 mol%, 40 mol% to 55 mol%, or 45 mol% to 55 mol%.

[0057] For example, the polyhydroxyalkanoate (PHA) resin may contain a resin containing 3-hydroxybutyric acid (3-HB) monomers and 4-hydroxybutyric acid (4-HB) monomers, or may contain 4-hydroxybutyric acid (4-HB) monomers in an amount of 1 mol % to 60 mol % based on the total number of moles of 3-hydroxybutyric acid (3-HB) monomers and 4-hydroxybutyric acid (4-HB) monomers.

[0058] When the content of the 4-HB monomer satisfies the above range, it may be more advantageous to obtain the desired effects according to the embodiment, and in particular, it is possible to simultaneously improve the processability and productivity during molding while also achieving excellent mechanical properties.

[0059] Furthermore, polyhydroxyalkanoate (PHA) contains at least one type of 4-HB monomer, and the crystallinity of the polyhydroxyalkanoate (PHA) can be controlled by adjusting the content of the 4-HB monomer. In other words, the polyhydroxyalkanoate (PHA) may be a polyhydroxyalkanoate (PHA) copolymer with adjusted crystallinity.

[0060] The crystallinity-adjusted polyhydroxyalkanoate (PHA) may be one whose crystallinity and amorphousness are adjusted by increasing the irregularities in the molecular structure, specifically by adjusting the type and ratio of monomers or the type and / or content of isomers.

[0061] On the other hand, polyhydroxyalkanoate (PHA) may have a glass transition temperature (Tg) of, 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.

[0062] The crystallization temperature (Tc) of polyhydroxyalkanoate (PHA) may not be measured, or may 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.

[0063] The melting temperature (Tm) of polyhydroxyalkanoate (PHA) may not be measured, and may be, for example, 100°C to 170°C, 110°C to 150°C, or 120°C to 140°C.

[0064] The weight-average molecular weight of the polyhydroxyalkanoate (PHA) can be, for example, 10,000 g / mol to 1,200,000 g / mol, such as 50,000 g / mol to 1,200,000 g / mol, 100,000 g / mol to 1,200,000 g / mol, 50,000 g / mol to 1,000,000 g / mol, 100,000 g / mol to 1,000,000 g / mol, or 200,000 g / mol. 0 g / mol to 1,200,000 g / mol, 250,000 g / mol to 1,150,000 g / mol, 300,000 g / mol to 1,100,000 g / mol, 350,000 g / mol to 1,000,000 g / mol, 350,000 g / mol to 950,000 g / mol, 100,000 g / mol to 900,000 g / mol, 200,000g / mol to 800,000g / mol, 200,000g / mol to 700,000g / mol, 250,000g / mol to 650,000g / mol, 200,000g / mol to 400,000g / mol, 300,000g / mol to 800,000g / mol, 300,000g / mol to 600,00 The molecular weight may be 0 g / mol, 500,000 g / mol to 1,200,000 g / mol, 500,000 g / mol to 1,000,000 g / mol, 550,000 g / mol to 1,050,000 g / mol, 550,000 g / mol to 900,000 g / mol, or 600,000 g / mol to 900,000 g / mol.

[0065] The polyhydroxyalkanoate (PHA) may have a melt index (MI) measured in accordance with ASTM D1238 at a temperature of 165°C under a load of 2.16 kg of 0.1 g / 10 min or more, 0.2 g / 10 min or more, 0.5 g / 10 min or more, 1 g / 10 min or more, 1.5 g / 10 min or more, or 2 g / 10 min or more, and may have a MI of 5 g / 10 min or less, 4.5 g / 10 min or less, or 4 g / 10 min or less.

[0066] For example, the melt index (MI) of the polyhydroxyalkanoate (PHA), measured in accordance with ASTM D1238 at a temperature of 165°C and a load of 2.16 kg, may be 0.1 g / 10 minutes to 5 g / 10 minutes, 0.1 g / 10 minutes to 4 g / 10 minutes, 0.1 g / 10 minutes to 3 g / 10 minutes, 0.1 g / 10 minutes to 2 g / 10 minutes, 0.5 g / 10 minutes to 5 g / 10 minutes, 0.5 g / 10 minutes to 4 g / 10 minutes, 0.5 g / 10 minutes to 3 g / 10 minutes, 0.5 g / 10 minutes to 2 g / 10 minutes, 1 g / 10 minutes to 5 g / 10 minutes, 1 g / 10 minutes to 4 g / 10 minutes, or 1 g / 10 minutes to 3 g / 10 minutes.

[0067] On the other hand, the polyhydroxyalkanoate (PHA) may contain a combination of two or more polyhydroxyalkanoates (PHAs) with different crystallinity, that is, by mixing two or more polyhydroxyalkanoates (PHAs) with different crystallinity, the 4-HB monomer content of the polyhydroxyalkanoate (PHA) can be adjusted to fall within the above-mentioned specific range.

[0068] Specifically, the polyhydroxyalkanoate (PHA) may include 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.

[0069] The first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin may be distinguished from each other in terms of any of the 4-HB monomer content, glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm).

[0070] Specifically, the first polyhydroxyalkanoate (PHA) resin may contain 4-HB monomer in an amount of, 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%, relative to the total number of moles of monomers contained in the first polyhydroxyalkanoate (PHA) resin.

[0071] The first polyhydroxyalkanoate (PHA) resin may have a glass transition temperature (Tg) of, 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.

[0072] The crystallization temperature (Tc) of the first polyhydroxyalkanoate (PHA) resin may not be measured, or may be, for example, 60°C to 120°C, 60°C to 110°C, 70°C to 120°C, or 75°C to 115°C.

[0073] The melting temperature (Tm) of the first polyhydroxyalkanoate (PHA) resin may not be measured, or may be, for example, 100°C to 170°C, 100°C to 160°C, 110°C to 160°C, or 120°C to 150°C.

[0074] The weight average molecular weight (Mw) of the first polyhydroxyalkanoate (PHA) resin is, for example, 10,000 g / mol to 1,200,000 g / mol, 10,000 g / mol to 1,000,000 g / mol, 50,000 g / mol to 1,000,000 g / mol, 50,000 g / mol to 1,200,000 g / mol, or 200,000 g / mol. The molecular weight of the polymer can be between 1,200,000 g / mol, 300,000 g / mol and 1,000,000 g / mol, 100,000 g / mol and 900,000 g / mol, 500,000 g / mol and 900,000 g / mol, 200,000 g / mol and 800,000 g / mol, or 200,000 g / mol and 400,000 g / mol.

[0075] The first polyhydroxyalkanoate (PHA) may have a melt index (MI) measured in accordance with ASTM D1238 at a temperature of 165°C under a load of 2.16 kg of 0.1 g / 10 minutes or more, 0.2 g / 10 minutes or more, 0.5 g / 10 minutes or more, 1 g / 10 minutes or more, 1.5 g / 10 minutes or more, or 2 g / 10 minutes or more, and may have a MI of 5 g / 10 minutes or less, 4.5 g / 10 minutes or less, or 4 g / 10 minutes or less.

[0076] The melt index (MI) of the first polyhydroxyalkanoate (PHA) resin, measured in accordance with ASTM D1238 at a temperature of 165°C and a load of 2.16 kg, may be, for example, 0.1 g / 10 minutes to 5 g / 10 minutes, 0.1 g / 10 minutes to 4 g / 10 minutes, 0.1 g / 10 minutes to 3 g / 10 minutes, 0.1 g / 10 minutes to 2 g / 10 minutes, 0.5 g / 10 minutes to 5 g / 10 minutes, 0.5 g / 10 minutes to 4 g / 10 minutes, 0.5 g / 10 minutes to 3 g / 10 minutes, 0.5 g / 10 minutes to 2 g / 10 minutes, 1 g / 10 minutes to 5 g / 10 minutes, 1 g / 10 minutes to 4 g / 10 minutes, or 1 g / 10 minutes to 3 g / 10 minutes.

[0077] On the other hand, the second polyhydroxyalkanoate (PHA) resin may contain 4-HB monomer in an amount of 0.1 mol % to 30 mol % relative to the total number of moles of monomers contained in the second polyhydroxyalkanoate (PHA) resin. For example, the second polyhydroxyalkanoate (PHA) resin may contain 4-HB monomer in an amount of 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%.

[0078] The first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin may be distinguished by their content of 4-HB monomer.

[0079] The second polyhydroxyalkanoate (PHA) resin may have a glass transition temperature (Tg) of, 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.

[0080] The glass transition temperature (Tg) of the first polyhydroxyalkanoate (PHA) resin and the glass transition temperature (Tg) of the second polyhydroxyalkanoate (PHA) resin may be different from each other.

[0081] The second polyhydroxyalkanoate (PHA) resin may have a crystallization temperature (Tc) of, for example, 70°C to 120°C, 75°C to 115°C, or 80°C to 110°C, or it may not be measured.

[0082] The second polyhydroxyalkanoate (PHA) resin may have a melting temperature (Tm) of, 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.

[0083] The weight average molecular weight (Mw) of the second polyhydroxyalkanoate (PHA) resin can be 10,000 g / mol to 1,200,000 g / mol, 50,000 g / mol to 1,100,000 g / mol, 100,000 g / mol to 1,000,000 g / mol, 300,000 g / mol to 1,000,000 g / mol, 100,000 g / mol to 900,000 g / mol, 200,000 g / mol to 800,000 g / mol, 200,000 g / mol to 600,000 g / mol, 200,000 g / mol to 400,000 g / mol, or 400,000 g / mol to 700,000 g / mol.

[0084] Specifically, the first polyhydroxyalkanoate (PHA) resin has a glass transition temperature (Tg) of -35°C to -15°C, and the second polyhydroxyalkanoate (PHA) resin satisfies at least one characteristic selected from a glass transition temperature (Tg) of -15°C to 0°C, a crystallization temperature (Tc) of 80°C to 110°C, and a melting temperature (Tm) of 120°C to 160°C, and the glass transition temperatures (Tg) of the first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin may be different. Also, the crystallization temperature (Tc) and melting temperature (Tm) of the first polyhydroxyalkanoate (PHA) resin may not be measured.

[0085] The second polyhydroxyalkanoate (PHA) may have a melt index (MI) measured in accordance with ASTM D1238 at a temperature of 165°C under a load of 2.16 kg of 0.1 g / 10 minutes or more, 0.2 g / 10 minutes or more, 0.5 g / 10 minutes or more, 1 g / 10 minutes or more, 1.5 g / 10 minutes or more, or 2 g / 10 minutes or more, and may have a MI of 5 g / 10 minutes or less, 4.5 g / 10 minutes or less, or 4 g / 10 minutes or less.

[0086] For example, the melt index (MI) of the second polyhydroxyalkanoate (PHA) resin, measured in accordance with ASTM D1238 at a temperature of 165°C and a load of 2.16 kg, may be 0.1 g / 10 min to 5 g / 10 min, 0.1 g / 10 min to 4 g / 10 min, 0.1 g / 10 min to 3 g / 10 min, 0.1 g / 10 min to 2 g / 10 min, 0.5 g / 10 min to 5 g / 10 min, 0.5 g / 10 min to 4 g / 10 min, 0.5 g / 10 min to 3 g / 10 min, 0.5 g / 10 min to 2 g / 10 min, 1 g / 10 min to 5 g / 10 min, 1 g / 10 min to 4 g / 10 min, or 1 g / 10 min to 3 g / 10 min.

[0087] The melt index (MI) of the first polyhydroxyalkanoate (PHA) resin and the melt index (MI) of the second polyhydroxyalkanoate (PHA) resin may be different from each other.

[0088] It may be more advantageous to achieve the effects desired in the present disclosure if the first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin each satisfy at least one of the 4-HB monomer content, glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and melt index (MI) within the above-mentioned ranges.

[0089] Furthermore, the first polyhydroxyalkanoate (PHA) resin and the second polyhydroxyalkanoate (PHA) resin may each be a polyhydroxyalkanoate (PHA) with controlled crystallinity.

[0090] For example, the first polyhydroxyalkanoate (PHA) resin may contain an amorphous polyhydroxyalkanoate (PHA) resin (hereinafter referred to as an aPHA resin), and the second polyhydroxyalkanoate (PHA) resin may contain a semi-crystalline polyhydroxyalkanoate (PHA) resin (hereinafter referred to as an scPHA resin).

[0091] Specifically, the first polyhydroxyalkanoate (PHA) resin may be an aPHA resin, or may be a mixed resin of an aPHA resin and an scPHA resin.

[0092] Specifically, the second polyhydroxyalkanoate (PHA) resin may be an scPHA resin, or may be a mixed resin of an aPHA resin and an scPHA resin.

[0093] aPHA resins and scPHA resins may be distinguished by their 4-HB monomer content, glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and melt index (MI).

[0094] The aPHA resin may contain, for example, 25 mol % to 50 mol % of 4-HB monomer relative to the total number of moles of monomers contained in the polyhydroxyalkanoate (PHA) resin.

[0095] The aPHA resin may have a glass transition temperature (Tg) of, for example, -35°C to -20°C.

[0096] The crystallization temperature (Tc) of the aPHA resin may not be measured.

[0097] The melting temperature (Tm) of the aPHA resin may not be measured.

[0098] The scPHA resin may contain, for example, 1 mol % to less than 25 mol % of 4-HB monomer relative to the total number of moles of monomers contained in the polyhydroxyalkanoate (PHA) resin.

[0099] The scPHA resin may have a glass transition temperature (Tg) of -20°C to 0°C.

[0100] The scPHA resin may have a crystallization temperature (Tc) of 75°C to 115°C.

[0101] The melting temperature (Tm) of the scPHA resin can be set to 110°C to 160°C.

[0102] 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, 1:0.5-3, 1:0.5-2.5, or 1:0.5-2.

[0103] According to one embodiment, the composition for biodegradable films can contain a polyhydroxyalkanoate (PHA) resin in an amount of 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, per 100 parts by weight of the total resin contained in the composition for biodegradable films.

[0104] For example, the composition for biodegradable films may contain a polyhydroxyalkanoate (PHA) resin in an amount of 10 to 100 parts by weight, 10 to 90 parts by weight, 10 to 80 parts by weight, 10 to 70 parts by weight, 10 to 60 parts by weight, 20 to 90 parts by weight, 20 to 80 parts by weight, 20 to 70 parts by weight, 20 to 60 parts by weight, 20 to 50 parts by weight, 30 to 90 parts by weight, 30 to 80 parts by weight, 30 to 70 parts by weight, 30 to 60 parts by weight, 30 to 50 parts by weight, or 30 to 40 parts by weight, per 100 parts by weight of all resins contained in the composition for biodegradable films.

[0105] When the content of the polyhydroxyalkanoate (PHA) resin satisfies the above range, it is possible to simultaneously improve mechanical properties such as tensile strength and elongation, processability during molding, and productivity.

[0106] biodegradable resin The composition for a biodegradable film according to one embodiment may further contain at least one resin selected from the group consisting of aliphatic polyester biodegradable resins and aliphatic / aromatic copolyester biodegradable resins as a component that imparts biodegradability while ensuring mechanical properties suitable for the intended use of the biodegradable film or a biodegradable product prepared using the same.

[0107] Specifically, the type of biodegradable resin is not particularly limited as long as it is a commonly used one. For example, the composition for a biodegradable film may contain 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). Specifically, the biodegradable resin may contain at least one selected from the group consisting of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), and thermoplastic starch (TPS). More specifically, the biodegradable resin may contain at least one selected from the group consisting of polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA).

[0108] According to one embodiment, the composition for a biodegradable film may further contain a polylactic acid (PLA) resin.

[0109] Unlike petroleum-based resins, polylactic acid (PLA) resin is based on biomass, making it a recyclable resource. It is also environmentally friendly because it is biodegradable by moisture and microorganisms when disposed of in landfills.

[0110] On the other hand, the weight average molecular weight (Mw) of polylactic acid (PLA) may be in the range of 10,000 to 1,000,000 g / mol, for example, 30,000 to 500,000 g / mol, 100,000 to 300,000 g / mol, or 100,000 to 200,000 g / mol. The weight average molecular weight (Mw) may be measured by gel permeation chromatography (GPC).

[0111] Polylactic acid (PLA) may include L-lactic acid, D-lactic acid, D,L-lactic acid, or a combination thereof.

[0112] Specifically, polylactic acid (PLA) may be a random copolymer of L-lactic acid and D-lactic acid.

[0113] The melting temperature (Tm) of polylactic acid (PLA) can be set to 100°C to 300°C, 120°C to 250°C, or 120°C to 200°C.

[0114] Polylactic acid (PLA) may have a glass transition temperature (Tg) of 30°C to 100°C, 30°C to 80°C, 40°C to 80°C, or 45°C to 70°C.

[0115] Specifically, the composition for a biodegradable film may contain polylactic acid (PLA) resin in an amount of 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, based on 100 parts by weight of all resins contained in the composition for a biodegradable film. Furthermore, the composition for a biodegradable film may contain polylactic acid (PLA) resin in an amount of 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, based on 100 parts by weight of all resins contained in the composition for a biodegradable film.

[0116] For example, the composition for biodegradable films may contain polylactic acid (PLA) resin in an amount of 5 to 90 parts by weight, 10 to 90 parts by weight, 20 to 90 parts by weight, 30 to 90 parts by weight, 40 to 90 parts by weight, 50 to 90 parts by weight, 60 to 90 parts by weight, 10 to 80 parts by weight, 20 to 80 parts by weight, 30 to 80 parts by weight, 40 to 80 parts by weight, 50 to 80 parts by weight, 60 to 80 parts by weight, 10 to 70 parts by weight, 20 to 70 parts by weight, 30 to 70 parts by weight, 40 to 70 parts by weight, 50 to 70 parts by weight, or 60 to 70 parts by weight, per 100 parts by weight of all resins contained in the composition for biodegradable films.

[0117] According to one embodiment, the composition for biodegradable films further contains a polylactic acid (PLA) resin, and the weight ratio of the polyhydroxyalkanoate (PHA) resin to the polylactic acid (PLA) resin may be 10:90 to 50:50, 20:80 to 50:50, 30:70 to 50:50, or 30:70 to 40:60.

[0118] When the composition for biodegradable films contains a polyhydroxyalkanoate (PHA) resin and a polylactic acid (PLA) resin, and the weight ratio of the polyhydroxyalkanoate (PHA) resin to the polylactic acid (PLA) resin satisfies the above range, the compatibility between the resins is good, which can be advantageous in achieving the desired effects.

[0119] Furthermore, the above-mentioned composition for biodegradable films can contain the biodegradable resin in an amount of 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, relative to 100 parts by weight of all resins contained in the composition for biodegradable films.

[0120] By including a biodegradable resin in the above range, the composition for a biodegradable film can have mechanical properties suitable for use as a biodegradable molded article, which has the advantage of being usable in a variety of applications. For example, by including a biodegradable resin, such as polylactic acid (PLA) resin, the composition for a biodegradable film can simultaneously improve tensile strength and elongation.

[0121] plasticizer 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 that is naturally derived and has a melting temperature of 95° C. to 250° C. When the plasticizer has a melting temperature within the above range, the plasticizer can be converted into a liquid phase having high fluidity during film formation, thereby increasing the melt flow of the biodegradable film composition. In particular, the use of a naturally derived plasticizer can be advantageous in terms of safety when used in food packaging materials, sanitary products, etc.

[0122] The melting temperature of the plasticizer may 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. If the melting temperature of the plasticizer satisfies the above range, the melt fluidity will be excellent, which can be very advantageous in terms of processability and productivity.

[0123] The plasticizer may include an adipic acid-based plasticizer. Specifically, the plasticizer may be adipic acid.

[0124] In particular, adipic acid is a naturally occurring additive that is harmless to the human body and can be used as a food additive. Therefore, when a biodegradable film composition containing adipic acid is used in food packaging materials or sanitary products, it has the great advantage of causing fewer side effects to the human body.

[0125] Adipic acid-based plasticizers such as adipic acid have a high melting temperature of approximately 152.1°C, making them easy to handle in a solid state at room temperature, and they become liquid at molding temperatures of 170°C or higher, making them highly fluid. Therefore, adipic acid can act as a plasticizer that can increase the melt flow of biodegradable film compositions.

[0126] In particular, the polyhydroxyalkanoate (PHA) resin contained in the composition for biodegradable films has a high or ultra-high molecular weight within the above range, unlike conventional polyester polymer resins. Generally, the higher the molecular weight, the lower the melt flow. Therefore, by including a plasticizer with a melting temperature within the above specific range in the composition for biodegradable films, such as an adipic acid-based plasticizer, the fluidity of the entire resin contained in the composition for biodegradable films at molding temperatures can be improved, thereby increasing the overall melt index of the composition for biodegradable films.

[0127] The melt index of a composition for a biodegradable film, or the fluidity of the resin contained in the composition, may be one of the most important factors in terms of processability and productivity when preparing a biodegradable film from the composition for a biodegradable film.

[0128] Specifically, when the composition for biodegradable films contains a plasticizer having a melting temperature within the above-mentioned specific range, the load imposed when using extrusion molding equipment (extruder) during molding of the biodegradable film or biodegradable product can be significantly reduced, and the quality of the final product can be further improved.

[0129] For example, when the composition for biodegradable films contains a plasticizer having a melting temperature within the above-mentioned specific range, the load on the extrusion equipment during extrusion molding, specifically the load (torque) on the screw inside the extruder, can be reduced, further improving processability and productivity, and further improving the quality of the final product.

[0130] The plasticizer content may be 0.01 phr or more, 0.05 phr or more, 0.07 phr or more, or 0.1 phr or more, and may be 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.

[0131] For example, the plasticizer content can be 0.01phr to 10phr, 0.01phr to 9phr, 0.01phr to 8phr, 0.01phr to 7phr, 0.01phr to 6phr, 0.01phr to 5phr, 0.01phr to 4phr, 0.01phr to 3phr, 0.01phr to 2phr, 0.01phr to 1phr, 0.01phr to less than 1phr, 0.01phr to 0.99phr, 0.01phr to 0.95phr, 0.01phr to 0.9phr, 0.01phr to 0.8phr, 0.01phr to 0.7phr, 0.01phr to 0.6phr r, 0.01 phr to 0.5 phr, 0.1 phr to 10 phr, 0.1 phr to 9 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 4 phr, 0.1 phr to 3 phr, 0.1 phr to 2 phr, 0.1 phr to 1 phr, 0.1 phr to 0.99 phr, 0.1 phr to 0.95 phr, 0.1 phr to 0.9 phr, 0.1 phr to 0.8 phr, 0.1 phr to 0.7 phr, 0.1 phr to 0.6 phr, or 0.1 phr to 0.5 phr.

[0132] Phr (per hundred resin) is the unit of the amount of material added to 100 parts by weight of total polymer resin (1 Phr: 1 g of material added when the polymer resin is 100 g).

[0133] When the plasticizer content satisfies the above range, the fluidity of the entire resin contained in the composition for biodegradable films is improved, and the melt index of the composition for biodegradable films can be adjusted to a range suitable for molding. This significantly reduces the load on molding equipment, particularly extruders, and simultaneously improves processability and productivity, further improving the quality of the final product.

[0134] On the other hand, the composition for a biodegradable film may contain a plasticizer other than the plasticizer having a melting temperature within the above specific range.

[0135] Other plasticizers may include at least one commonly used plasticizer such as glycerin, sorbitol, 1,4-butanediol, ethylene glycol, maltose, sucrose, cyclodextrin, glucose, propylene glycol, urea, polyethylene glycol, and polypropylene glycol, but are not limited to these.

[0136] When the composition for biodegradable films is used as a mixture of a plasticizer having a melting temperature within a specific range and the other plasticizers described above, the weight ratio of the plasticizer having a melting temperature within the specific range to the other plasticizers described above 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 these ranges as long as the desired effect is not impaired.

[0137] additives The composition for biodegradable films may further contain at least one additive selected from the group consisting of chain extenders, antioxidants, compatibilizers, weighting agents, nucleating agents, melt strength enhancers, and lubricants.

[0138] The content of the additives may be 0.1 phr to 50 phr relative to 100 parts by weight of all resins contained in the composition for biodegradable films. For example, the content of the additives 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 may be 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.

[0139] The chain extender can adjust the composition for a biodegradable film to have a desired viscosity that satisfies commercial properties so that it can be applied to various molding processes that require high or ultra-high viscosity conditions, such as blow molding, injection molding, and extrusion molding. The chain extender also has the great advantage of simultaneously improving processability and productivity.

[0140] The chain extender may include at least one selected from the group consisting of an epoxy compound, an acrylic compound, and an isocyanate compound. Specifically, the chain extender may include an epoxy compound.

[0141] The epoxy compound may contain an epoxy group as a functional group, and 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.

[0142] For example, the epoxy compound may include a compound having a molecular weight of 100 g / mol to 50,000 g / mol, 100 g / mol to 35,000 g / mol, 100 g / mol to 30,000 g / mol, 100 g / mol to 25,000 g / mol, 100 g / mol to 20,000 g / mol, 200 g / mol to 10,000 g / mol, 300 g / mol to 10,000 g / mol, 300 g / mol to 8,000 g / mol, 300 g / mol to 400 g / mol, 5,000 g / mol to 8,000 g / mol, 6,000 g / mol to 8,000 g / mol, or 7,000 g / mol to 8,000 g / mol.

[0143] The epoxy compound may include a styrene acrylate copolymer having 5 to 9 epoxy groups, a bisphenol A-diglycidyl ether polymer having two epoxy groups, or a combination thereof. More specifically, the epoxy compound may include a styrene acrylate copolymer having 5 or 9 epoxy groups. For example, the epoxy compound may include Joncryl ADR 4468 from BASF.

[0144] The chain extender may include an acrylic compound. The acrylic compound may include an acrylic group, and the acrylic group may be attached to the main chain as a side chain.

[0145] The chain extender may include an isocyanate-based compound. The isocyanate-based compound may be at least one selected from the group consisting of monofunctional isocyanates and polyfunctional isocyanates. For example, the chain extender may be at least one selected from the group consisting of tolylene 2,4-diisocyanate, tolylene 2,6-diisocyanate, diphenylmethane 4,4'-diisocyanate, 2,4'-diisocyanate, naphthalene 1,5-diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, and isophorone diisocyanate. The chain extender may also include at least one selected from the group consisting of triisocyanate, tri(4-isocyanatophenyl)methane, and methylenebis(4-isocyanatocyclohexane).

[0146] The chain extender may 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.

[0147] The antioxidant is an additive that prevents decomposition by ozone or oxygen, or prevents oxidation during storage, and prevents deterioration of the physical properties of the biodegradable film or biodegradable product formed from the biodegradable film composition.

[0148] As the antioxidant, any commonly used antioxidant can be used as long as it does not impair the desired effect.

[0149] Specifically, the antioxidant may include at least one selected from the group consisting of hindered phenol-based antioxidants and phosphite-based (phosphorus-based) antioxidants.

[0150] The hindered phenol-based antioxidant may include, for example, at least one selected from the group consisting of 4,4'-methylenebis(2,6-di-t-butylphenol), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), and 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0151] The phosphite (phosphorus) antioxidant may include at least one selected from the group consisting of, for example, tris-(2,4-di-t-butylphenyl)phosphite, bis-(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis-(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, distearyl-pentaerythritol diphosphite, [bis(2,4-di-t-butyl-5-methylphenoxy)phosphino]biphenyl, and N,N-bis[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxyphosphepin-6-yl]oxy]-ethyl]ethanamine.

[0152] The antioxidant may 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.

[0153] When the content of the antioxidant satisfies the above range, the physical properties of the biodegradable film or biodegradable product formed from the composition for biodegradable films can be improved, which may be more advantageous in terms of achieving the desired effects.

[0154] The compatibilizer is an additive that eliminates the non-uniformity of the copolymerized polyhydroxyalkanoate (PHA) resin and imparts compatibility.

[0155] As the compatibilizer, any commonly used one may be used as long as it does not impair the above-mentioned effect.

[0156] Specifically, the compatibilizer may 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 may include at least one selected from the group consisting of ethylene vinyl alcohol, polyvinyl alcohol (PVA), and ethylene vinyl acetate. For example, the compatibilizer may include Wacker's Vinnex 2526.

[0157] The compatibilizer may 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.

[0158] When the content of the compatibilizer satisfies the above range, the compatibility between the resin used and the additives is increased, thereby improving the physical properties of the biodegradable film or biodegradable product formed from the biodegradable film composition, which may be more advantageous in achieving the desired effects.

[0159] The bulking agent is an inorganic material, and is an additive that increases the crystallization rate during molding to improve moldability and alleviate the problem of rising costs associated with the use of biodegradable resins.

[0160] As the weighting agent, any commonly used inorganic material can be used as long as it does not impair the desired effect.

[0161] Specifically, the weighting agent may contain at least one selected from the group consisting of calcium carbonate such as light calcium carbonate or heavy calcium carbonate, silica, talc, kaolin, barium sulfate, clay, calcium oxide, magnesium hydroxide, titanium oxide, carbon black, and glass fiber.

[0162] The weighting agent may have an average particle size of 0.5 μm to 10 μm. If the average particle size of the weighting agent is smaller than the above range, it may be difficult to disperse the particles. If the average particle size exceeds the above range, the particle size may become too large, which may impair the effect.

[0163] The weighting agent may 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.

[0164] When the content of the weighting agent satisfies the above range, the desired effect may be more advantageously achieved.

[0165] A nucleating agent is an additive that complements or changes the crystallization morphology of a polymer and increases the solidification rate when the polymer melt is cooled. In particular, the polyhydroxyalkanoate (PHA) resin used in one embodiment has a slow solidification rate, which may make it unsuitable for processability as a soft material. By using such a nucleating agent, the solidification rate can be increased, further improving processability, moldability, and productivity, and the desired physical properties can be effectively achieved.

[0166] A conventional nucleating agent may be used within a range that does not impair the above-mentioned effects.

[0167] Specific examples of the nucleating agent include elemental substances (pure substances); carbon black, calcium carbonate, synthetic silicic acid 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, organic phosphorus metal salts, metal compounds including complex oxides such as boron nitride; octylic acid, toluic acid, heptanoic acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, cerotic acid, montanic acid, melamine acid, methylparaben ... low molecular weight organic compounds having a carboxylic acid metal group, such as benzoic acid, benzoic acid, p-tert-butylbenzoic acid, terephthalic acid, terephthalic acid monomethyl ester, isophthalic acid, and metal salts of isophthalic acid monomethyl ester; 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 with olefins (e.g., ethylene, propylene, butene-1, etc.), copolymers of acrylic acid or methacrylic acid with styrene, copolymers of olefins and methyl anhydrides, Polymeric organic compounds having a carboxylic acid metal group, such as copolymers of styrene and maleic anhydride, and salts of copolymers of styrene and maleic anhydride; polymers of α-olefins having five or more carbon atoms branched at the third carbon atom (e.g., 3,3-dimethylbutene-1, 3-methylbutene-1, 3-methylpentene-1, 3-methylhexene-1, 3,5,5-trimethylhexene-1), polymers of vinylcycloalkanes (e.g., vinylcyclopentane, vinylcyclohexane, vinylnorbornane), polyalkylene glycols (e.g., polyethylene glycol, polypropylene), Examples of suitable organic compounds include polymeric organic compounds such as diphenyl phosphate, diphenyl phosphite, metal salts of bis(4-tert-butylphenyl)phosphate, and methylene bis-(2,4-tert-butylphenyl)phosphate; sorbitol derivatives such as bis(p-methylbenzylidene)sorbitol and bis(p-ethylbenzylidene)sorbitol; and thioglycolic anhydride and metal salts of p-toluenesulfonic acid.The above nucleating agents may be used alone or in combination of two or more kinds.

[0168] The nucleating agent may 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.

[0169] When the content of the nucleating agent satisfies the above range, the solidification rate can be increased to improve moldability, and the solidification rate can be increased in the cutting process, preparation process, etc. of pellet production, thereby further improving productivity and processability.

[0170] Melt strength enhancers are additives that improve the melt strength of the reactants.

[0171] As the melt strength enhancer, any commonly used one may be used as long as it does not impair the above-mentioned effect.

[0172] Specifically, the melt strength enhancer may include at least one selected from the group consisting of polyester, styrene-based polymer (acrylonitrile butadiene styrene, polystyrene, etc.), polysiloxane, organo-modified siloxane polymer, and maleic anhydride-grafted ethylene propylene diene monomer (MAH-g-EPDM).

[0173] The melt strength enhancer may 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.

[0174] If the content of the melt strength enhancing agent satisfies the above range, it can be advantageous in that the desired effect can be more effectively obtained.

[0175] Lubricants are additives that increase the slipperiness (slipperiness) during extrusion and prevent the surfaces of the film or sheet from sticking together during processing.

[0176] The lubricant may be any commonly used lubricant as long as it does not impair the above-mentioned effects. For example, the lubricant may be at least one selected from the group consisting of erucamide, oleamide, and stearamide.

[0177] The lubricant may 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.

[0178] When the content of the lubricant satisfies the above range, the processability, productivity, and moldability may be further improved, which may be advantageous in terms of obtaining the desired effects more effectively.

[0179] The above-mentioned composition for a biodegradable film may contain a crosslinking agent and / or a stabilizer as additional additives.

[0180] The crosslinking agent is an additive that changes the properties of the polyhydroxyalkanoate (PHA) resin and increases the molecular weight of the resin. Conventional crosslinking agents may be used as long as they do not impair the above effects.

[0181] For example, the crosslinking agent may be at least one selected from the group consisting of fatty acid esters, natural oils containing epoxy groups (epoxidized natural oils), diallyl phthalate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, diethylene glycol dimethacrylate, and bis(2-methacryloxyethyl) phosphate.

[0182] The crosslinking agent may 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.

[0183] The stabilizer is an additive for protecting the composition from oxidation and heat and preventing discoloration. Any commonly used stabilizer may be used as the stabilizer as long as the above-mentioned effects are not impaired.

[0184] Specifically, the stabilizer may be one selected from the group consisting of trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, and phosphorous acid.

[0185] The stabilizer may 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.

[0186] On the other hand, the composition for a biodegradable film may further contain a carrier resin.

[0187] The carrier resin may be in the form of a masterbatch capable of carrying or delivering the functional additive.

[0188] For example, the carrier resin may include a polybutylene adipate terephthalate (PBAT)-based resin. Specifically, the carrier resin may include a masterbatch including a polybutylene adipate terephthalate (PBAT)-based resin.

[0189] The carrier resin supports or transports additives used to impart functionality to the composition or film, even if the additives have poor dispersibility. This allows the desired functionality to be efficiently imparted without the side effects of using functional additives with poor dispersibility, and allows excellent biodegradability and mechanical properties to be maintained.

[0190] The carrier resin, such as polybutylene adipate terephthalate (PBAT)-based resin, can 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) may be measured by gel permeation chromatography (GPC).

[0191] Polybutylene adipate terephthalate (PBAT) resins are aliphatic-aromatic polyester copolymers, and can be obtained by polycondensation of 1,4-butanediol, adipic acid, terephthalic acid, dimethyl terephthalate, or the like, using a known method.

[0192] 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 satisfies the above range, the desired function can be efficiently imparted without causing side effects.

[0193] Properties of biodegradable film compositions According to one embodiment, the composition for a biodegradable film has a melt index that is very advantageous for achieving excellent processability and productivity, and therefore, during film molding, processability and productivity can be simultaneously improved, and a biodegradable film and a biodegradable product with excellent biodegradability, optical properties, and mechanical properties can be provided. In particular, the load on molding equipment when preparing a biodegradable film or a biodegradable final product can be minimized, and the quality of the product can be further improved.

[0194] First, the composition for a biodegradable film is fed into an extruder equipped with a 6 rpm screw, and extruded at a screw rotation speed of 200 rpm and 170°C. When the pressure inside the extruder is 46 bar or less, the load (torque) on the screw should be 70% or less.

[0195] When the composition for a biodegradable film is extruded, the load on the screw can be significantly reduced, and productivity, processability, and moldability can be improved.

[0196] Specifically, the load (torque) applied to the screw may be less than 70%, 65% or less, 60% or less, 59% or less, or 58% or less when the pressure inside the extruder is 46 bar or less.

[0197] In one embodiment, at a pressure of 46 bar or less in the extruder, the load (torque) on the screw can be 60% or less, less than 60%, 59% or less, 58% or less, 55% or less, or 54% or less.

[0198] In other embodiments, at a pressure of 40 bar to 46 bar in the extruder, the load (torque) on 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%.

[0199] In other embodiments, the pressure in the extruder may be greater than 35 bar and less than 40 bar, and the load (torque) on the screw may 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%.

[0200] Furthermore, the load (torque) applied to the screw may 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% when the pressure inside the extruder is 30 bar to 35 bar.

[0201] Furthermore, the load (torque) applied to the screw may 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% when the pressure inside the extruder is 25 bar to less than 30 bar.

[0202] In an extruder equipped with a screw, the ratio (L / D) of the screw length (L) to the screw diameter (D) may be 20 to 50, and the screw diameter (D) may be 15Φ to 30Φ. For example, in an extruder equipped with a screw, the ratio (L / D) of the screw length (L) to the screw diameter (D) may be 40, and the screw diameter (D) may be 19Φ, but is not limited thereto.

[0203] Additionally, the load and pressure applied to the screw may vary depending on the type of extruder.

[0204] In one embodiment, the composition for a biodegradable film may have physical properties suitable for various molding processes such as extrusion molding, injection molding, compression molding, pneumatic molding, blow molding, and thermoforming.

[0205] For example, the composition for a biodegradable film may have physical properties suitable for extrusion molding, and therefore may be a composition for a biodegradable extruded film to be used in extrusion molding.

[0206] Biodegradable film In one embodiment, a biodegradable film is provided that includes the biodegradable film composition.

[0207] The biodegradable film can be biodegraded by any of microorganisms, moisture, oxygen, light, and heat, and has excellent mechanical properties.

[0208] 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.

[0209] Tensile strength is measured in accordance with ASTM D882 by cutting a biodegradable film into a length of 10 cm and a width of 1 cm and attaching it to a universal testing machine (UTM) with a chuck spacing of 20 mm. The test is performed at a room temperature of 25°C and a pulling speed of 200 mm / min, and the tensile strength is measured using a program installed in the machine. If the tensile strength satisfies the above range, the mechanical properties, productivity, processability, and moldability of the biodegradable film can be further improved simultaneously, which can be advantageous in achieving the desired effects.

[0210] The biodegradable film may also have an elongation of 200% or more, 250% or more, 270% or more, 280% or more, 290% or more, or 295% or more, and 900% or less, 800% or less, 700% or less, 600% or less, 500% or less, 480% or less, or 450% or less.

[0211] For example, the elongation of the biodegradable film may 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%.

[0212] In one embodiment, the biodegradable film has a tensile strength of 10 MPa to 50 MPa and an elongation of 200% or more.

[0213] Elongation is measured in accordance with ASTM D882 by cutting the biodegradable film into a size of 10 cm in length and 1 cm in width and attaching it to a universal testing machine (UTM) with a chuck spacing of 20 mm. The maximum deformation just before break is measured at a tensile speed of 200 mm / min. The ratio of the maximum deformation to the initial length is calculated as the elongation.

[0214] On the other hand, the biodegradable film may have excellent optical properties.

[0215] Specifically, the biodegradable film can have a haze of 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 will be significantly reduced, which may limit its use in packaging applications where the contents inside can be seen, for example.

[0216] The biodegradable film is characterized by excellent mechanical properties and over 90% biodegradability in soil and the ocean.

[0217] Biodegradability refers to the rate of decomposition relative to a standard material (e.g., cellulose) over the same period. The Korean Ministry of Environment defines a biodegradable material as one that is 90% or more biodegradable relative to the standard material. Specifically, the marine biodegradability measured in accordance with the EL724 standard is 90% or more.

[0218] The biodegradable film may include a biodegradable extruded film prepared by extruding a composition for a biodegradable film.

[0219] Method for preparing biodegradable films In one embodiment, a method for preparing a biodegradable film using the biodegradable film composition is provided.

[0220] Specifically, the method for preparing the biodegradable film may include a first step of preparing a composition for a biodegradable film, and a second step of supplying the composition to an extruder and extruding it.

[0221] The method for preparing the biodegradable film will be described in detail below.

[0222] First, the method for preparing the biodegradable film includes a first step of preparing a composition for the biodegradable film.

[0223] Specifically, the first step may include mixing a polyhydroxyalkanoate (PHA) resin with a plasticizer having a melting temperature of 95°C to 250°C.

[0224] The polyhydroxyalkanoate (PHA) resin and plasticizer are as described above.

[0225] The composition for biodegradable films may use a polyhydroxyalkanoate (PHA) resin alone as the main resin, or may contain a mixed resin in which a polyhydroxyalkanoate (PHA) resin is mixed with the above-mentioned biodegradable resin.

[0226] For example, the composition for the biodegradable film may contain a polyhydroxyalkanoate (PHA) resin and a polylactic acid (PLA) resin.

[0227] The composition for biodegradable films may also be prepared by adding a plasticizer having a melting temperature within the above-mentioned specific range to the mixed resin.

[0228] Alternatively, the biodegradable film composition may be prepared by adding a plasticizer having a melting temperature within the above-mentioned specific range and the above-mentioned additives to the mixed resin. In such cases, the additives may be selected and used in various ways depending on the application and the desired effect, but are not limited to these.

[0229] For example, a composition for a biodegradable film may be prepared by mixing a mixed resin of polyhydroxyalkanoate (PHA) resin and polylactic acid (PLA) resin as the main resin with additives such as a plasticizer, a chain extender, a compatibilizer, and a weighting agent.

[0230] The types and contents of the components contained in the main resin and the additives are as described above.

[0231] The composition for a biodegradable film may further contain a carrier resin capable of supporting or transporting the above-mentioned additives and / or functional additives.

[0232] That is, the first step may include adding a carrier resin to a polyhydroxyalkanoate (PHA) resin and a plasticizer having a melting temperature of 95°C to 250°C. The carrier resin may include a polybutylene adipate terephthalate (PBAT)-based resin. Specifically, the carrier resin may include a polybutylene adipate terephthalate (PBAT)-based masterbatch. The type and content of the carrier resin are as described above.

[0233] On the other hand, the method for preparing the biodegradable film includes a second step of supplying the composition for a biodegradable film to an extruder and extruding it.

[0234] The composition for a biodegradable film according to one embodiment may be extruded into a shape suitable for the intended use. For example, the composition for a biodegradable film may be provided in the form of pellets and then extruded to form a biodegradable film, or the composition for a biodegradable film may be directly extruded to form a biodegradable film.

[0235] The molding may be carried out using extrusion molding.

[0236] The extruder may be a single-screw extruder or a twin-screw extruder.

[0237] The extruder may be a T-die twin screw extruder equipped with screws.

[0238] Figure 1 is a partial cross-sectional view of an extruder used in accordance with one embodiment. Referring to Figure 1, the extruder (100) may include a feeder (110), a compression section (120), a screw (130), a header (140), and a die (150).

[0239] The extrusion conditions may vary depending on the intended use of the biodegradable film, but extrusion may be carried out by a commonly used method.

[0240] The composition for a biodegradable film may 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.

[0241] The rotation speed of the screw (130) of the extruder (100) may be, for example, 100 rpm to 300 rpm, 120 rpm to 280 rpm, 150 rpm to 250 rpm, or 180 rpm to 230 rpm.

[0242] The extrusion temperature may be from 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 140°C to 175°C, for example.

[0243] For example, based on the temperature measured at the die (150) of the extruder (100), the extrusion temperature may be set to 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.

[0244] The extrusion temperature may 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, based on the temperature measured at the head (header) (140) of the extruder (100).

[0245] When the extrusion molding conditions satisfy the above ranges, it may be more advantageous to achieve the desired effects.

[0246] Additionally, the load and pressure applied to the screw may vary depending on the type of extruder.

[0247] Furthermore, according to one embodiment, a step of preheating the composition for biodegradable films (preheating step) may be further carried out before feeding the composition to the die of the extruder.

[0248] The preheating step may be carried out at, for example, 110° C. to 170° C. Specifically, the preheating step may be carried out by gradually increasing the temperature with a temperature gradient, for example, starting from 110° C., then 130° C., 150° C., and 170° C.

[0249] According to one embodiment, the extrusion pressure may 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, more than 35 bar to less than 40 bar, or 30 bar to 35 bar. Here, the extrusion pressure may be, for example, the pressure in the head section (header) (140) of the extruder (100).

[0250] When the extrusion pressure satisfies the above range, the load (torque) applied to the molding equipment, particularly the screw, during extrusion molding can be minimized, processability and productivity can be improved simultaneously, and the quality of the final product can be further improved.

[0251] The method for preparing the biodegradable film may further include heat treatment (heat setting) and / or drying after molding. The treatment conditions for these steps may be the same as those used in the present technology, as long as they do not impair the desired effects.

[0252] In one embodiment, a biodegradable product is provided that includes the biodegradable film or the composition for a biodegradable film described above.

[0253] The biodegradable product may include at least one selected from the group consisting of primary packaging, secondary packaging for food, electronic products, or hygiene products, straws, trays, food containers, and adhesive products.

[0254] MODE FOR CARRYING OUT THE INVENTION The present disclosure will be described in more detail below with reference to the following examples. However, the following examples are for the purpose of illustrating the present disclosure and are not intended to limit the scope of the present disclosure to these examples alone. [Example]

[0255] Example 1 As shown in Table 1 below, a biodegradable film composition was prepared by mixing a 40:60 weight ratio mixture of polyhydroxyalkanoate (PHA) resin (3-HB-co-4-HB, aPHA, 4-HB content: 34 mol%) (CJ) and polylactic acid (PLA) resin (Natureworks, 4032D) with polybutylene adipate terephthalate (PBAT) (Encore Bioplastics) as a carrier resin, and additives such as Vinnex 2526 (compatibilizer, Wacker), Joncryl ADR 4468 (chain extender, BASF), adipic acid (plasticizer, BASF), and calcium carbonate (CaCO3) (weighting agent, Junsei Chemical).

[0256] The above composition for biodegradable film was supplied to a T-die twin-screw extruder (BA-19, Bautek) and subjected to T-die extrusion molding under the processing conditions of temperature and speed shown in Table 2 below to prepare a biodegradable film.

[0257] Examples 2 to 4 Compositions for biodegradable films and biodegradable films 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.

[0258] Examples 5 to 7 A composition for a biodegradable film and a biodegradable film were prepared in the same manner as in Example 1, except that the mixing weight ratio of polyhydroxyalkanoate (PHA) resin to polylactic acid (PLA) resin and the content of adipic acid were changed as shown in Table 1 below.

[0259] Evaluation example Evaluation example 1: Tensile strength The biodegradable films prepared from each of the above biodegradable film compositions were cut into test pieces measuring 10 cm in length and 1 cm in width, and attached to a universal testing machine (4206-001, manufacturer: UTM) with a chuck spacing of 20 mm in accordance with ASTM D 882. The test was carried out at room temperature of 25°C at a tensile speed of 200 mm / min, and the tensile strength was measured using a program installed in the machine.

[0260] Evaluation example 2: Elongation The biodegradable films prepared from each of the above biodegradable film compositions were cut into test pieces measuring 10 cm in length and 1 cm in width, and attached to a universal testing machine (4206-001, manufacturer: UTM) with a chuck spacing of 20 mm in accordance with ASTM D882. The test was carried out at a tensile speed of 200 mm / min, and the maximum deformation immediately before breakage was measured. The ratio of the maximum deformation to the initial length was calculated as the elongation.

[0261] Evaluation example 3: Workability The processability of each biodegradable film composition was determined by the pressure (bar) at the extruder header and the load (torque, %) on the motor when the extruder was used. The load on the motor was evaluated using a measuring device built into the device.

[0262] The specific composition, mechanical properties, and melt index of each biodegradable film composition obtained in the Examples are summarized in Table 1 below, and the processing conditions during extrusion molding and the results of processability evaluation are summarized in Table 2 below.

[0263] [Table 1]

[0264] [Table 2]

[0265] As can be seen from Table 2 above, the biodegradable film compositions prepared in Examples 1 to 7 had a low load (torque) on the screw of approximately 53% to approximately 60% at a pressure of 46 bar or less inside the extruder, and the biodegradable films prepared from each biodegradable film composition had a tensile strength of approximately 20 MPa or more and an elongation of approximately 295.4% or more, and were excellent in processability and mechanical properties.

[0266] Specifically, in the biodegradable film compositions prepared in Examples 1 to 3, which had a weight ratio of polylactic acid (PLA) to polyhydroxyalkanoate (PHA) of 60:40, increasing the plasticizer content from 0.1 phr to 0.5 phr reduced the pressure inside the extruder from approximately 40 bar to approximately 34 bar, and reduced the load (torque) on the screw from 60% to 55%. The biodegradable films prepared from each biodegradable film composition exhibited excellent mechanical properties, with tensile strengths of approximately 26.7 MPa to approximately 27.3 MPa and elongations of approximately 370.2% to approximately 440.7%.

[0267] In addition, when the plasticizer content was increased from 0.1 phr to 0.3 phr in the biodegradable film compositions prepared in Examples 5 and 6, which had a PLA to polyhydroxyalkanoate (PHA) weight ratio of 70:30, the pressure inside the extruder decreased from approximately 46 bar to approximately 44 bar, and the load (torque) on the screw decreased from approximately 60% to approximately 55%. The biodegradable films prepared from each biodegradable film composition exhibited excellent mechanical properties, with tensile strengths of approximately 28.0 MPa to approximately 29.5 MPa and elongations of approximately 295.4% to approximately 345.6%.

[0268] Furthermore, the biodegradable film compositions prepared in Examples 1 to 7 contain a biodegradable resin and an environmentally friendly additive, adipic acid, making them highly desirable from the standpoint of excellent biodegradability and environmental friendliness, and can be applied in a variety of 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, When the composition for a biodegradable film is supplied to an extruder equipped with a 6 rpm screw and extruded at a screw rotation speed of 200 rpm and 170°C, the pressure inside the extruder is 46 bar or less and the load (torque) on the screw is 70% or less.

2. The composition for biodegradable films 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 polyhydroxyalkanoate (PHA) resin has 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 Melting temperature (Tm) between 100°C and 170°C The composition for a biodegradable film according to claim 1 , which satisfies at least one of the above requirements.

5. 2. The biodegradable film composition according to claim 1, wherein the polyhydroxyalkanoate (PHA) resin comprises at least one monomer selected from the group consisting of 4-hydroxybutyric acid (4-HB), 3-hydroxybutyric acid (3-HB), 3-hydroxypropionic acid (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 biodegradable film composition according to claim 5, wherein the polyhydroxyalkanoate (PHA) resin comprises a polyhydroxyalkanoate (PHA) copolymer (PHA copolymer) containing a 4-hydroxybutyric acid (4-HB) monomer, and the 4-hydroxybutyric acid (4-HB) monomer is used in an amount of 1 mol % to 99 mol % based on the total number of moles of the monomers contained in the polyhydroxyalkanoate (PHA) copolymer.

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

8. 2. The biodegradable film composition 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 biodegradable film composition 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 10:90 to 50:

50.

10. 2. The composition for biodegradable films according to claim 1, further comprising at least one additive selected from the group consisting of a chain extender, an antioxidant, a compatibilizer, a weighting agent, a nucleating agent, a melt strength enhancer, and a lubricant, and the content of the additive is 0.1 phr to 50 phr.

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

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

13. 1. A method for preparing a biodegradable film, comprising: A first step of preparing the composition for a biodegradable film according to claim 1; a second step of supplying the composition for a biodegradable film to an extruder and extruding it; A method for preparing a biodegradable film, comprising:

14. 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 95°C to 250°C.

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