Biodegradable resin composition, biodegradable nonwoven fabric, and method for producing the same

Abstract

The present invention relates to a biodegradable resin composition, a biodegradable nonwoven fabric, and a method for producing the same. Specifically, one embodiment of the present invention provides a biodegradable resin composition that contains a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a plasticizer. The biodegradable resin composition has a melt flow index (MFI) of 5 g / 10 min or greater at 190°C and 2.16 kg as measured in accordance with ASTM D1238. This provides excellent biodegradability and biocompatibility, environmental friendliness, and excellent processability and productivity. This allows for the production of high-quality spunbond nonwoven fabrics or staple fiber nonwoven fabrics, and allows for easy control of properties such as viscosity appropriate for the process, thereby improving productivity and processability.

Description

[Technical Field]

[0001] The present invention relates to a biodegradable resin composition, a biodegradable nonwoven fabric, and a method for producing the same. [Background technology]

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

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

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

[0005] Nonwoven fabrics are industrial textile materials used in a variety of fields, for example, as a component material in filtration processes to control suspended particles such as airborne particles and gases, or to control the purity of water used in industrial sites such as food processing. In particular, since the 2000s, there has been growing concern about the harmful effects of yellow sand, fine dust, and ultrafine dust on the human body, and the novel coronavirus outbreak of 2019 has led to increased interest in nonwoven fabrics used as filtration materials, leading to active research into these materials.

[0006] Conventionally, petrochemical polymer materials have been used as materials for nonwoven fabrics. However, because petrochemical polymer materials are difficult to recover and recycle after use, they are left in the soil and ocean, causing serious environmental pollution. Biodegradable polymers that can improve biodegradability have been used, but the raw materials are expensive, and there are limitations to improving the filtration, air permeability, flexibility, and other properties required for nonwoven fabrics.

[0007] Furthermore, nonwoven fabrics are mainly produced by the meltblowing method or the spunbonding method. Compared to the meltblowing method, the spunbonding method has excellent processability, allowing for the production of fibers and nonwoven fabrics with a variety of physical properties. Staple fiber nonwoven fabrics can be produced by applying the meltblowing method and / or the spunbonding method in one or two stages, making it easier to control the desired physical properties and therefore applicable to various industrial fields. Therefore, there is a need for the development of a biodegradable resin composition that is excellent in biodegradability and biocompatibility, and that can easily control properties such as viscosity suitable for the process, allowing the production of high-quality spunbond nonwoven fabrics or staple fiber nonwoven fabrics, and therefore also has excellent productivity and processability. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 2012-0103158 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a biodegradable resin composition that is environmentally friendly due to its excellent biodegradability and biocompatibility, and that has excellent productivity and processability, allowing for the production of high-quality spunbond nonwoven fabrics or staple fiber nonwoven fabrics, and that allows for easy control of properties such as viscosity suitable for the process. [Means for solving the problem]

[0010] A biodegradable resin composition according to one embodiment of the present invention comprises a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, and has a melt flow index (MFI) of 5 g / 10 min or more as measured at 190°C and 2.16 kg in accordance with ASTM D1238.

[0011] According to one embodiment of the present invention, the fluidizing agent may include at least one selected from the group consisting of polystyrene-based, polyacrylate-based, and polystyrene-acrylate-based polymers.

[0012] According to one embodiment of the present invention, the fluidizing agent may have a specific gravity of 0.7 to 1.8 and a weight average molecular weight of 1,500 g / mol to 8,000 g / mol.

[0013] According to one embodiment of the present invention, the fluidizing agent may have a glass transition temperature (Tg) of 40°C or greater, as measured by differential scanning calorimetry (DSC), and a melt flow index of 1,800 g / 10 min or greater at 130°C and 12 kg, as measured according to ASTM D1238.

[0014] According to one embodiment of the present invention, the biodegradable resin composition may contain the fluidizing agent in an amount of 0.1 phr to 20 phr.

[0015] According to one embodiment of the present invention, the PHA resin may contain 0.1% to 60% by weight of 4-hydroxybutyric acid (4-HB) repeat units.

[0016] According to one embodiment of the present invention, the PHA resin may comprise a first PHA resin.

[0017] According to one embodiment of the present invention, the first PHA resin may contain 15% to 60% by weight of 4-hydroxybutyric acid (4-HB) repeating units and have a melt flow index (MFI) of 0.1 g / 10 min to 20 g / 10 min when measured at 165°C and 5 kg in accordance with ASTM D1238.

[0018] According to one embodiment of the present invention, the PHA resin may include a second PHA resin.

[0019] According to one embodiment of the present invention, the second PHA resin may contain 0.1% to 30% by weight of 4-hydroxybutyric acid (4-HB) repeating units and have a melt flow index of 0.1 g / 10 min to 15 g / 10 min when measured at 165°C and 5 kg in accordance with ASTM D1238.

[0020] According to one embodiment of the present invention, the biodegradable resin composition may contain at least one biodegradable resin selected from the group consisting of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene succinate (PBS), 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).

[0021] According to one embodiment of the present invention, the weight ratio of the PHA resin to the biodegradable resin may be 1:99 to 99:1.

[0022] According to one embodiment of the present invention, the weight ratio of the PHA resin to the polylactic acid resin may be 20:80 to 70:30.

[0023] According to one embodiment of the present invention, the biodegradable resin composition may further comprise at least one additive selected from the group consisting of pigments, dye absorbers, light absorbers, antioxidants, compatibilizers, extenders, nucleating agents, melt strength agents, and slip agents.

[0024] According to one embodiment of the present invention, the PHA resin may further comprise at least one repeat unit selected from the group consisting of 3-hydroxybutyric acid (3-HB), 3-hydroxypropionic acid (3-HP), 3-hydroxyhexanoate (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

[0025] According to one embodiment of the present invention, the biodegradable resin composition may have a glass transition temperature (Tg) of -35°C to 15°C, a melting temperature (Tm) of 105°C to 200°C, a crystallization temperature (Tc) of 50°C to 120°C or not measured, and a cold crystallization temperature (Tcc) of 30°C to 125°C, as measured by a differential scanning calorimeter (DSC).

[0026] Another embodiment of the present invention provides a biodegradable nonwoven fabric comprising biodegradable fibers, the biodegradable fibers comprising a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units, and a fluidizing agent.

[0027] According to another embodiment of the present invention, the biodegradable fibers may have an average length of 100 mm or less and an average diameter of 1 μm to 100 μm.

[0028] According to another embodiment of the present invention, it may be prepared by a spunbond process.

[0029] According to yet another embodiment of the present invention, the biodegradable resin composition of the present invention may be prepared from a biodegradable resin composition, and the biodegradable resin composition may have a melt flow index (MFI) of 5 g / 10 min or greater when measured at 190°C and 2.16 kg according to ASTM D1238.

[0030] According to another embodiment of the present invention, the biodegradable fiber may be a bicomponent fiber with a different cross section, or a bicomponent fiber of two or more or three or more components.

[0031] According to another embodiment of the present invention, the biodegradable fiber may be of a sheath-core type having a core and a sheath, a side-by-side type, a sea-island type, or a segmented pie type.

[0032] A method for producing a biodegradable nonwoven fabric according to another embodiment of the present invention includes melt-spinning pellets produced by melt-extruding a biodegradable resin composition, wherein the biodegradable resin composition comprises a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, and has a melt flow index (MFI) of 5 g / 10 min or greater when measured at 190°C and 2.16 kg in accordance with ASTM D1238.

[0033] According to another embodiment of the present invention, the step of spinning the biodegradable resin composition may be performed using a sheath-core composite spinning device.

[0034] According to another embodiment of the present invention, in a sheath-core composite spinning apparatus having a core and a sheath, the weight ratio of raw materials supplied to the core and sheath may be 5:95 to 95:5.

[0035] According to another embodiment of the present invention, the core may be provided with the biodegradable resin composition. [Effects of the Invention]

[0036] A biodegradable resin composition according to one embodiment of the present invention comprises a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, and has a melt flow index (MFI) of 5 g / 10 min or greater as measured at 190°C and 2.16 kg in accordance with ASTM D1238. Therefore, the composition is environmentally friendly due to its excellent biodegradability and biocompatibility, and its excellent productivity and processability allow the production of high-quality spunbond nonwoven fabrics or staple fiber nonwoven fabrics. Properties such as viscosity suitable for processing can be easily controlled, improving productivity and processability.

[0037] Specifically, when a spunbond nonwoven fabric or a staple fiber nonwoven fabric is produced from the biodegradable resin composition, the biodegradable resin composition has excellent viscosity characteristics, so that the nonwoven fabric can be produced under lower pressure and temperature conditions than conventionally, resulting in excellent productivity and processability and enabling the quality of the produced nonwoven fabric to be improved.

[0038] Furthermore, not only can a biodegradable nonwoven fabric be produced directly from the biodegradable resin composition, but also a biodegradable nonwoven fabric can be produced using biodegradable pellets obtained from the biodegradable resin composition, which is convenient in that a variety of processes can be selected as needed.

[0039] Furthermore, as described above, the biodegradable resin composition that is biodegradable in both soil and the ocean and the biodegradable nonwoven fabric made therefrom have excellent thermal and mechanical properties, and can be advantageously applied to a variety of fields and can exhibit excellent properties. DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention will be described in detail below. The present invention is not limited to the disclosure given below, and the invention may be embodied in various forms without departing from the gist of the present invention.

[0041] 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.

[0042] Numerical values ​​and expressions relating to amounts of components, reaction conditions, etc. used herein can be understood even if modified by the word "approximately," unless otherwise specified.

[0043] 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.

[0044] Biodegradable resin composition A biodegradable resin composition according to one embodiment of the present invention comprises a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, and has a melt flow index (MFI) of 5 g / 10 min or more as measured at 190°C and 2.16 kg in accordance with ASTM D1238.

[0045] Nonwoven fabrics are fabrics made by bonding fiber aggregates or films by physical or chemical means, regardless of whether they are spun, woven, or knitted. They are produced directly from fibers, either by the fusion strength of the fibers themselves or by the entanglement of the fibers. Traditionally, nonwoven fabrics have been produced using petrochemical materials such as polypropylene (PP), but their biodegradability is low. For this reason, a method using polylactic acid (PLA) as a nonwoven fabric material has been proposed. However, the degree of improvement in biodegradability is not significant. Due to its low flexibility and rough and stiff texture, PLA has poor usability and wearing comfort, making it difficult to apply to various fields.

[0046] A biodegradable resin composition according to one embodiment of the present invention contains a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, and has a melt flow index (MFI) of 5 g / 10 min or more at 190°C and 2.16 kg as measured in accordance with ASTM D1238. Therefore, the composition is environmentally friendly due to its excellent biodegradability and biocompatibility, and its excellent productivity and processability allow the production of high-quality spunbond nonwoven fabrics or staple fiber nonwoven fabrics. Properties such as viscosity suitable for processing can be easily controlled, improving productivity and processability.

[0047] In particular, when producing a nonwoven fabric from the biodegradable resin composition, the biodegradable resin composition has excellent viscosity characteristics, making it easy to produce the nonwoven fabric under conditions of lower pressure and temperature than conventional methods, resulting in excellent productivity and processability and enabling the quality of the produced nonwoven fabric to be improved.

[0048] Specifically, the biodegradable resin composition may be a composition for biodegradable nonwoven fabrics.

[0049] A biodegradable resin composition according to one embodiment of the present invention comprises a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units.

[0050] The biodegradable resin composition according to one embodiment of the present invention comprises a polyhydroxyalkanoate (PHA) resin, which is a copolymerized polyhydroxyalkanoate resin containing 4-hydroxybutyric acid (4-HB) repeating units, more specifically, a specific first PHA resin and / or a specific second PHA resin having 4-HB repeating units. This composition has excellent biodegradability and biocompatibility, making it environmentally friendly and allowing the easy production of biodegradable nonwoven fabrics with excellent properties.

[0051] Furthermore, as described above, the biodegradable resin composition that is biodegradable in both soil and the ocean and the biodegradable nonwoven fabric made therefrom have excellent thermal and mechanical properties, and can be advantageously applied to a variety of fields and can exhibit excellent properties.

[0052] PHA is a natural thermoplastic polyester polymer that accumulates within microbial cells. Because it is a biodegradable material, it can be composted and ultimately decomposes into carbon dioxide, water, and organic waste without producing hazardous waste. In particular, PHA is biodegradable in soil and the ocean, so biodegradable resin compositions and biodegradable fibers or biodegradable nonwoven fabrics prepared therefrom may have environmentally friendly properties when they contain PHA resin. Therefore, the biodegradable resin compositions and biodegradable nonwoven fabrics prepared therefrom have the significant advantage of being biodegradable and environmentally friendly, making them applicable in a variety of fields.

[0053] Specifically, PHA is a natural thermoplastic polyester polymer that accumulates within microbial cells. When a bacterium is supplied with nutrients (nitrogen sources, phosphorus, etc.) unevenly, it accumulates PHA within the cell and stores carbon and energy.

[0054] Furthermore, PHA has similar physical properties to conventional petroleum-derived synthetic polymers such as polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polybutylene succinate terephthalate (PBST), and polybutylene succinate adipate (PBSA), and is completely biodegradable and has excellent biocompatibility.

[0055] In particular, unlike other environmentally friendly plastic materials such as PBS, PLA, and PTT, PHA can be synthesized from over 150 types of monomers, and depending on the type of monomer, hundreds of different types of PHA can be prepared. Depending on the type of monomer, there are hundreds of different types of PHA, each with completely different structures and properties.

[0056] PHA resins may be composed of a single monomer repeat unit within living cells, or may be formed by polymerizing one or more types of monomer repeat units. Specifically, PHA resins may be homopolyhydroxyalkanoate resins (hereinafter referred to as HOMO PHA resins) or copolymerized polyhydroxyalkanoate resins (hereinafter referred to as copolymerized PHA resins), i.e., copolymers in which different repeat units are randomly distributed in the polymer chain.

[0057] Examples of repeating units that the PHA resin may have include 2-hydroxybutyrate, lactic acid, glycolic acid, 3-hydroxybutyric acid (hereinafter referred to as 3-HB), 3-hydroxypropionic acid (hereinafter referred to as 3-HP), 3-hydroxyvalerate (hereinafter referred to as 3-HV), 3-hydroxyhexanoate (hereinafter referred to as 3-HH), 3-hydroxyheptanoate (hereinafter referred to as 3-HHep), 3-hydroxyoctanoate (hereinafter referred to as 3-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-hydroxybutyric acid (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 PHA resin may contain one or more repeating units selected from the above.

[0058] Specifically, the PHA resin may contain one or more repeating units selected from the group consisting of 3-HB, 4-HB, 3-HP, 3-HH, 3-HV, 4-HV, 5-HV, and 6-HH.

[0059] That is, the PHA resin may be a HOMO type PHA resin composed only of 4-HB repeating units, or a copolymer type PHA resin containing 4-HB repeating units.

[0060] The PHA resin may be a copolymer PHA resin containing 4-HB repeating units and one other repeating unit different from the 4-HB repeating units, or may be a copolymer PHA resin containing two, three, four, five, six or more different repeating units. For example, the PHA resin may be poly-3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter referred to as 3HB-co-4HB).

[0061] Furthermore, the PHA resin may contain isomers. For example, the PHA resin may contain structural isomers, enantiomers, or geometric isomers. Specifically, the PHA resin may contain structural isomers.

[0062] The PHA resin may also be a copolymer PHA resin with controlled crystallinity. For example, the PHA resin may contain at least one type of 4-HB repeating unit, and the crystallinity of the PHA resin may be adjusted by controlling the content of the 4-HB repeating unit.

[0063] For example, the PHA resin may be a copolymer PHA resin containing at least one repeating unit selected from the group consisting of 3-hydroxybutyric acid (3-HB), 4-hydroxybutyric acid (4-HB), 3-hydroxypropionic acid (3-HP), 3-hydroxyhexanoate (3-HH), 3-hydroxyvalerate (3-HV), 4-hydroxyvalerate (4-HV), 5-hydroxyvalerate (5-HV), and 6-hydroxyhexanoate (6-HH).

[0064] Specifically, the copolymer PHA resin contains 4-HB repeating units and may further contain one or more repeating units selected from the group consisting of 3-HB repeating units, 3-HP repeating units, 3-HH repeating units, 3-HV repeating units, 4-HV repeating units, 5-HV repeating units, and 6-HH repeating units. More specifically, the PHA resin may have 4-HB repeating units and 3-HB repeating units.

[0065] More specifically, the PHA resin may contain 0.1 to 60% by weight of 4-HB repeating units. For example, the PHA resin may be a copolymer PHA resin containing 4-HB repeating units and 3-HB repeating units, and may contain 0.1 to 60% by weight of 4-HB repeating units.

[0066] The PHA resin may contain 4-HB repeat units in an amount of 0.5% to 50% by weight, 1% to 48% by weight, 3% to 46% by weight, 5% to 45% by weight, 8% to 40% by weight, 10% to 38% by weight, 15% to 35% by weight, 20% to 30% by weight, 0.5% to 25% by weight, 1% to 20% by weight, 2% to 15% by weight, 3% to 10% by weight, 20% to 60% by weight, 25% to 55% by weight, or 35% to 50% by weight.

[0067] The PHA resin may also be a copolymer PHA resin containing 4-HB repeating units and 3-HB repeating units, and may contain 20% or more by weight of 3-HB repeating units. For example, the PHA resin may contain 3-HB repeating units in an amount of 35% or more, 40% or more, 50% or more, 60% or more, 70% or more, or 75% or more to 99% or less, 98% or less, 97% or less, 96% or less, 95% or less, 93% or less, 91% or less, 90% or less, 80% or less, 70% or less, 60% or less, or 55% or less.

[0068] The crystallinity-adjusted PHA resin may be one in which the degree of crystallinity and amorphousness are adjusted as the degree of disorder in the molecular structure increases, specifically by adjusting the type or proportion of monomers or the type or content of isomers.

[0069] According to one embodiment of the present invention, the PHA resin may contain two or more PHA resins with different crystallinity. Specifically, two or more PHA resins with different crystallinity may be mixed together to prepare a resin having a 4-HB repeat unit content within the above-mentioned specific range.

[0070] Specifically, the PHA resin may contain a first PHA, which is an amorphous PHA resin with controlled crystallinity.

[0071] The first PHA resin is an amorphous PHA resin with controlled crystallinity (hereinafter referred to as aPHA resin) and can contain 4-HB repeat units in an amount of 15% to 60% by weight, 15% to 55% by weight, 20% to 55% by weight, 25% to 55% by weight, 30% to 55% by weight, 35% to 55% by weight, 20% to 50% by weight, 25% to 50% by weight, 30% to 50% by weight, 35% to 50% by weight, or 20% to 40% by weight.

[0072] The glass transition temperature (Tg) of the first PHA resin may be -45°C to -10°C, -35°C to -15°C, -35°C to -20°C, or -30°C to -20°C. The crystallization temperature (Tc) of the first PHA resin may not be measured, or may be 60°C to 120°C, 60°C to 110°C, 70°C to 120°C, or 75°C to 115°C. The melting temperature (Tm) of the first PHA resin may be unmeasurable, or may be 100°C to 170°C, 100°C to 160°C, 110°C to 160°C, or 120°C to 150°C. The cold crystallization temperature (Tcc) of the first PHA resin may not be measurable, or may be 30°C to 125°C, 30°C to 120°C, 40°C to 110°C, or 50°C to 100°C.

[0073] In this specification, the glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and cold crystallization temperature (Tcc) can be measured using a differential scanning calorimeter (DSC). Specifically, the glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and cold crystallization temperature (Tcc) can be measured by performing the first or second scan in the differential scanning calorimetry (DSC) mode, and can be confirmed from the heat flow curve obtained by these scans. More specifically, the glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and cold crystallization temperature (Tcc) can be confirmed from the heat flow curve obtained when the temperature is increased from 40°C to 180°C at 10°C / min and then cooled to -50°C at 10°C / min.

[0074] The first PHA resin may have a melt flow index (MFI) of 0.1 g / 10 min to 20 g / 10 min at 165° C. and 5 kg, measured in accordance with ASTM D1238. For example, the melt flow index (MFI) of the first PHA resin measured in accordance with ASTM D1238 at 165°C and 5 kg may be 0.1 g / 10 min to 15 g / 10 min, 0.1 g / 10 min to 12 g / 10 min, 0.1 g / 10 min to 10 g / 10 min, 0.1 g / 10 min to 8 g / 10 min, 0.1 g / 10 min to 6 g / 10 min, 0.1 g / 10 min to 5.5 g / 10 min, 0.5 g / 10 min to 10 g / 10 min, 1 g / 10 min to 10 g / 10 min, 2 g / 10 min to 8 g / 10 min, 3 g / 10 min to 6 g / 10 min, or 3 g / 10 min to 5.5 g / 10 min.

[0075] The weight average molecular weight of the first PHA resin can be 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, 200,000 g / mol to 1,200,000 g / mol, 250,000 g / mol to 1,000,000 g / mol, 100,000 g / mol to 900,000 g / mol, 500,000 g / mol to 900,000 g / mol, 200,000 g / mol to 800,000 g / mol, or 200,000 g / mol to 500,000 g / mol.

[0076] The PHA resin may also contain a second PHA resin that is a semi-crystalline PHA resin.

[0077] The second PHA resin may be a semi-crystalline PHA resin with controlled crystallinity (hereinafter referred to as scPHA resin) containing 0.1 to 30% by weight of 4-HB repeat units. For example, the second PHA resin may contain 4-HB repeat units in an amount of 0.1 to 30% by weight, 0.5 to 30% by weight, 1 to 29% by weight, 3 to 29% by weight, 1 to 28% by weight, 1.5 to 25% by weight, 2 to 20% by weight, 2.5 to 15% by weight, 3 to 25% by weight, 5 to 21% by weight, 6 to 18% by weight, 10 to 30% by weight, 10 to 20% by weight, 13 to 23% by weight, or 15 to 20% by weight.

[0078] The glass transition temperature (Tg) of the second PHA resin may be -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. The crystallization temperature (Tc) of the second PHA resin may be 70°C to 120°C, 75°C to 120°C, or 75°C to 115°C. The melting temperature (Tm) of the second PHA resin may be 105°C to 165°C, 110°C to 160°C, 115°C to 155°C, or 120°C to 150°C. The cold crystallization temperature (Tcc) of the second PHA resin may be immeasurable or may be 35°C to 125°C, 35°C to 120°C, 45°C to 110°C, or 55°C to 100°C.

[0079] The second PHA resin may have a melt flow index of 0.1 g / 10 min to 15 g / 10 min at 165° C. and 5 kg, measured in accordance with ASTM D1238. For example, the melt flow index (MFI) of the second PHA resin at 165°C and 5 kg, measured in accordance with ASTM D1238, may be 0.1 g / 10 min to 10 g / 10 min, 0.2 g / 10 min to 7 g / 10 min, 0.5 g / 10 min to 5.5 g / 10 min, 0.6 g / 10 min to 5 g / 10 min, 0.8 g / 10 min to 5 g / 10 min, 1 g / 10 min to 5 g / 10 min, 0.1 g / 10 min to 5 g / 10 min, 1 g / 10 min to 6.5 g / 10 min, 1.5 g / 10 min to 15 g / 10 min, 3 g / 10 min to 10 g / 10 min, 3.5 g / 10 min to 12 g / 10 min, or 4.5 g / 10 min to 10 g / 10 min.

[0080] The weight average molecular weight of the second PHA resin can be 10,000 g / mol to 1,200,000 g / mol, 50,000 g / mol to 1,100,000 g / mol, 50,000 g / mol to 350,000 g / mol, 100,000 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 500,000 g / mol, or 500,000 g / mol to 1,200,000 g / mol.

[0081] The first PHA resin and the second PHA resin may be distinguished by the content of 4-HB repeating units and may have at least one property selected from the group consisting of glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), cold crystallization temperature (Tcc), and melt flow index. Specifically, the first PHA and the second PHA may be distinguished by the content of 4-HB repeating units, glass transition temperature (Tg), crystallization temperature (Tg), melting temperature (Tm), cold crystallization temperature (Tcc), and melt flow index. For example, the content of 4-HB repeating units in the first PHA resin may be different from the content of 4-HB repeating units in the second PHA.

[0082] According to one embodiment of the present invention, the PHA resin may include either a first PHA resin or a second PHA resin, or may include both a first PHA resin and a second PHA resin.

[0083] Specifically, by having the PHA resin comprise a first PHA resin which is an amorphous PHA resin, or by having both a first PHA resin which is an amorphous PHA resin and a second PHA resin which is a semi-crystalline PHA resin, more specifically by adjusting the contents of the first PHA resin and the second PHA resin, the desired physical properties can be controlled more effectively.

[0084] According to one embodiment of the present invention, the PHA resin may include a first PHA resin or a second PHA resin. Specifically, the PHA resin may be composed solely of the first PHA resin or solely of the second PHA resin.

[0085] According to another embodiment of the present invention, the PHA resin may include a first PHA resin and a second PHA resin. In this case, the weight ratio of the first PHA resin to the second PHA resin may be 1:0.5-5. For example, the weight ratio of the first PHA resin to the second PHA resin may be 1:0.5-4.5, 1:0.6-4.2, or 1:0.7-3.5. When the weight ratio of the first PHA resin to the second PHA resin satisfies the above range, desired physical properties can be more effectively controlled.

[0086] The glass transition temperature (Tg) of the PHA resin may be -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, -20°C to 0°C, -15°C to 0°C, or -15°C to -5°C.

[0087] The crystallization temperature (Tc) of the PHA resin may not be measured or may be 60°C to 120°C, 60°C to 110°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.

[0088] The melting temperature (Tm) of the PHA resin may not be measurable, but may be 100°C to 170°C, 105°C to 170°C, 105°C to 165°C, 110°C to 160°C, 115°C to 155°C, 110°C to 150°C, 120°C to 150°C, or 120°C to 140°C.

[0089] The cold crystallization temperature (Tcc) of the PHA resin may not be measurable, or may be between 30°C and 125°C, between 40°C and 115°C, or between 50°C and 105°C.

[0090] The PHA resin may have a decomposition temperature (Td, 5% weight loss) measured by a thermogravimetric analyzer (TGA) of 220°C to 280°C, 245°C to 275°C, 255°C to 270°C, or 260°C to 270°C.

[0091] In this specification, the decomposition temperature (Td) is measured using a thermogravimetric analyzer (TGA). Specifically, the decomposition temperature (Td) of a PHA resin can be determined as the temperature at which the weight decreases by 5% from a weight change curve when the temperature is increased from room temperature to 600°C at a heating rate of 10°C / min using a thermogravimetric analyzer (TGA).

[0092] The weight-average molecular weight of the PHA resin may be 10,000 g / mol to 1,200,000 g / mol. For example, the weight-average molecular weight of the PHA resin may be 50,000 g / mol to 1,200,000 g / mol, 100,000 g / mol to 1,000,000 g / mol, 200,000 g / mol to 1,200,000 g / mol, 250,000 g / mol to 1,150,000 g / mol, 300,000 g / mol to 1,100,000 g / mol, 350,000 g / mol to 950,000 g / mol, 100,000 g / mol to 900,000 g / mol, 200,000 g / mol to 8 ..., 250,000 g / mol, 250,000 g / mol, 250,000 g / mol, 250,000 g / mol, 250,000 g / mol, 250,000 g / mol, 250,000 g / mol, 250,000 g / mol, 250,000 g / mol, 250,000 g / The molecular weight may be 0 g / mol to 650,000 g / mol, 200,000 g / mol to 400,000 g / mol, 300,000 g / mol to 600,000 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, 600,000 g / mol to 900,000 g / mol, or 500,000 g / mol to 900,000 g / mol.

[0093] The PHA resin may have a crystallinity of 90% or less as measured by differential scanning calorimetry (DSC). For example, the crystallinity of the PHA resin may be 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less as measured by differential scanning calorimetry.

[0094] The PHA resin may have an average particle size of 0.5 μm to 5 μm. For example, the average particle size of the PHA resin may be 0.7 μm to 4.6 μm, 1.1 μm to 4.5 μm, 1.5 μm to 4.3 μm, 2.2 μm to 4.2 μm, 2.6 μm to 4.0 μm, 2.8 μm to 3.9 μm, or 3.1 μm to 3.8 μm.

[0095] The average particle size of the PHA resin can be measured using a nanoparticle size analyzer (e.g., Zetasizer Nano ZS). Specifically, the average particle size of the PHA is measured by dynamic light scattering (DLS) using a Zetasizer Nano ZS (manufactured by Malvern Instruments) at a temperature of 25°C and a measurement angle of 175°. In this case, the peak value derived from the polydispersion index (PDI) is taken as the particle size with a confidence interval of 0.5.

[0096] The PHA resin may have a polydispersion index (PDI) of less than 2.5. For example, the PHA resin may have a dispersity index of 2.4 or less, 2.3 or less, 2.1 or less, or 2.0 or less.

[0097] Alternatively, the PHA resin may be obtained by cell disruption using a non-mechanical or chemical method. Specifically, since the PHA resin is a natural thermoplastic polyester polymer that accumulates within microbial cells and has a relatively large average particle size, it may be obtained through a disruption process to more effectively control the yield and physical properties of the desired material or to improve process efficiency.

[0098] The biodegradable resin composition may contain 15% by weight or more of the PHA resin relative to the total weight of the biodegradable resin composition. For example, the content of the PHA resin may be 20% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 50% by weight or more, 65% by weight or more, 70% by weight or more, 85% by weight or more, or 90% by weight or more relative to the total weight of the biodegradable resin composition.

[0099] The biodegradable resin composition according to one embodiment of the present invention contains a fluidizing agent.

[0100] Specifically, the fluidizing agent may contain at least one selected from the group consisting of polystyrene-based, polyacrylate-based, and polystyrene-acrylate-based polymers. By including a polystyrene-based fluidizing agent, it is possible to more efficiently control viscosity characteristics and reduce the torque or pressure of the extruder during processing, thereby improving productivity and processability, but this is not a limitation.

[0101] The specific gravity of the fluidizing agent may be 0.7 to 1.8. For example, the specific gravity of the fluidizing agent may be 0.75 to 1.5, 0.8 to 1.35, or 0.95 to 1.2.

[0102] The fluidizing agent may have a weight average molecular weight of 1,500 g / mol to 8,000 g / mol. For example, the weight average molecular weight of the fluidizing agent may be 1,600 g / mol to 7,000 g / mol, 1,700 g / mol to 5,000 g / mol, 1,900 g / mol to 3,500 g / mol, or 2,100 g / mol to 3,200 g / mol.

[0103] The fluidizing agent may also have a glass transition temperature (Tg) of 40° C. or higher as measured by differential scanning calorimetry. For example, the glass transition temperature (Tg) of the fluidizing agent may be 42° C. or higher, 45° C. or higher, 50° C. or higher, 53° C. or higher, 55° C. or higher, or 58° C. or higher as measured by differential scanning calorimetry (DSC).

[0104] The fluidizing agent may have a melt flow index of 1,800 g / 10 min or greater when measured at 130° C. and 12 kg according to ASTM D 1238. For example, the melt flow index of the fluidizing agent measured at 130° C. and 12 kg according to ASTM D 1238 may be 2,100 g / 10 min or greater, 2,400 g / 10 min or greater, 2,600 g / 10 min or greater, 2,800 g / 10 min or greater, 3,000 g / 10 min or greater, 3,500 g / 10 min or greater, or 4,500 g / 10 min or greater.

[0105] The biodegradable resin composition may contain a fluidizer in an amount of 0.1 to 20 phr. For example, the content of the fluidizer may be 0.2 to 15 phr, 0.3 to 10 phr, 0.5 to 8 phr, 0.8 to 6 phr, 0.9 to 4 phr, 0.95 to 3 phr, 0.1 to 10 phr, 0.1 to 5 phr, or 0.1 to 2.5 phr. When the content of the fluidizer satisfies the above range, the desired effects of the present invention may be more effectively achieved.

[0106] Meanwhile, according to yet another embodiment of the present invention, the biodegradable resin composition may comprise at least one biodegradable resin selected from the group consisting of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene succinate (PBS), 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).

[0107] By using a biodegradable resin together with a PHA resin, the dispersibility, processability, and productivity of the biodegradable resin composition can be further improved.

[0108] The biodegradable resin composition may contain less than 90% by weight of the biodegradable resin relative to the total weight of the biodegradable resin composition. For example, the content of the biodegradable resin may be 85% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 45% by weight or less, or 35% by weight or less relative to the total weight of the biodegradable resin composition. Specifically, the content of the biodegradable resin may be, but is not limited to, 35% by weight to 80% by weight, 45% by weight to 75% by weight, or 50% by weight to 70% by weight.

[0109] According to another embodiment of the present invention, the weight ratio of PHA resin to biodegradable resin may be 1:99 to 99:1. For example, the weight ratio of PHA resin to biodegradable resin may be 5:95 to 99:5, 10:90 to 90:10, 15:90 to 60:40, 5:95 to 45:55, 10:90 to 40:60, 15:85 to 35:65, or 20:80 to 30:70. When the weight ratio of PHA resin to biodegradable resin satisfies the above range, productivity and processability can be improved without reducing biodegradability.

[0110] Specifically, the biodegradable resin may be a polylactic acid (PLA) resin.

[0111] More specifically, the weight ratio of PHA resin to PLA resin may be 10:90 to 70:30. For example, the weight ratio of PHA resin to PLA resin may be 10:90 to 65:35, 15:85 to 55:45, 15:85 to 50:50, or 20:80 to 30:70. When the weight ratio of PHA resin to PLA resin satisfies the above range, productivity and processability can be further improved without impairing biodegradability.

[0112] On the other hand, according to another embodiment of the present invention, the biodegradable resin composition may contain at least one additive selected from the group consisting of a pigment, a dye absorber, a light absorber, an antioxidant, a compatibilizer, an extender, a nucleating agent, a melt strength agent, and a slip agent.

[0113] The pigment may include at least one selected from the group consisting of inorganic particles, carbon black, and cobalt green. The inorganic particles may be, but are not limited to, metal particles such as Cu, metal oxides, metalloid oxides, or combinations thereof.

[0114] The pigment content may be 0.01 phr to 20 phr, 0.01 phr to 15 phr, 0.01 phr to 12 phr, 0.01 phr to 10 phr, 0.01 phr to 8 phr, 0.01 phr to 5 phr, 0.2 phr to 4.5 phr, 0.2 phr to 4 phr, or 0.5 phr to 3 phr.

[0115] The antioxidant is an additive for preventing decomposition by ozone or oxygen, preventing oxidation during storage, or preventing deterioration of physical properties. Conventional antioxidants may be used as long as they do not impair the effects of the present invention.

[0116] Specifically, the antioxidant may include at least one selected from the group consisting of hindered phenol-based antioxidants and phosphite (phosphorus-based) antioxidants.

[0117] 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.

[0118] 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.

[0119] The content of the antioxidant may be 0.01 to 20 phr, 0.01 to 15 phr, 0.01 to 12 phr, 0.01 to 10 phr, 0.01 to 8 phr, 0.01 to 5 phr, 0.2 to 4.5 phr, 0.2 to 4 phr, or 0.5 to 3 phr. By satisfying the above range of the content of the antioxidant, physical properties can be improved, and the desired effects of the present invention may be more effectively obtained.

[0120] The compatibilizer is an additive that imparts compatibility by eliminating the mold releasability of the biodegradable resin and / or PHA resin. A general compatibilizer may be used as long as it does not impair the effects of the present invention.

[0121] 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, maleic anhydride, and glycerin stearate.

[0122] The content of the compatibilizer may be 0.01 to 20 phr, 0.01 to 15 phr, 0.01 to 12 phr, 0.01 to 10 phr, 0.01 to 8 phr, 0.01 to 5 phr, 0.2 to 4.5 phr, 0.2 to 4 phr, or 0.5 to 3 phr. When the content of the compatibilizer satisfies the above range, the compatibility between the resins used is increased, the physical properties are improved, and the desired effects of the present invention may be more advantageously achieved.

[0123] The extender is an inorganic material and additive for increasing the crystallization rate of the synthetic resin during the molding process, thereby improving moldability, and for reducing the problem of rising costs due to the use of highly biodegradable resins. General inorganic materials may be used as long as they do not impair the effects of the present invention.

[0124] The bulking agent may contain at least one selected from the group consisting of inorganic materials such as zinc and calcium, stearic acid, light or heavy calcium carbonate, silica, talc, kaolin, barium sulfate, clay, calcium oxide, magnesium hydroxide, titanium oxide, carbon black, and glass fiber.

[0125] The average particle size of the bulking agent may be 0.5 μm to 5 μm. For example, the average particle size of the bulking agent may be 0.5 μm to 4.8 μm, 0.5 μm to 4.5 μm, or 0.7 μm to 4 μm. If the average particle size of the bulking agent is less than 0.5 μm, it is difficult to disperse the particles. If it exceeds 5 μm, the particle size becomes too large, which may impair the effects of the present invention.

[0126] The content of the extender may be 0.01 to 20 phr, 0.01 to 15 phr, 0.01 to 12 phr, 0.01 to 10 phr, 0.01 to 8 phr, 0.01 to 5 phr, 0.2 to 4.5 phr, 0.2 to 4 phr, or 0.5 to 3 phr. By ensuring that the content of the extender satisfies the above range, it can be advantageous in terms of further achieving the desired effects of the present invention.

[0127] Nucleating agents are additives that complement or change the crystalline morphology of polymers and increase the crystallization (solidification) rate when the polymer melt is cooled. In particular, the PHA resin used in the present invention has a slow crystallization rate, which can make the process difficult to carry out due to the slow crystallization rate. To solve this problem, the use of this type of nucleating agent increases the crystallization rate, further improving processability, moldability, and productivity, and effectively achieving desired physical properties.

[0128] A conventional nucleating agent may be used as long as it does not impair the effects of the present invention. Specifically, the nucleating agent may include, for example, a metal compound consisting of a simple substance (pure substance) or a composite oxide, a low-molecular-weight organic compound having a metal carboxylate group, a high-molecular-weight organic compound having a metal carboxylate group, a high-molecular-weight organic compound, phosphoric acid or phosphorous acid or a metal salt thereof, a sorbitol derivative, thioglycolic anhydride, and p-toluenesulfonic acid or a metal salt thereof. The above nucleating agents may be used alone or in combination of two or more.

[0129] The metal compound consisting of a simple substance (pure substance) or a composite oxide may be at least one selected from the group consisting of carbon black, calcium carbonate, synthetic silicic acid and its salts, silica, zinc white, clay, sulphuric acid, 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.

[0130] The low molecular weight organic compound having a metal carboxylate group may be at least one selected from the group consisting of, for example, octylic acid, toluic acid, heptanoic acid, pelargonic 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, terephthalic acid monomethyl ester, isophthalic acid, and metal salts of isophthalic acid monomethyl ester.

[0131] The polymeric organic compound having a metal carboxylate group may be at least one selected from the group consisting of, for example, a metal salt of carboxylic acid group-containing polyethylene obtained by oxidation of polyethylene, a carboxylic acid group-containing polypropylene obtained by oxidation of polypropylene, a copolymer of acrylic acid or methacrylic acid with an olefin (ethylene, propylene, butene-1, etc.), a copolymer of acrylic acid or methacrylic acid with styrene, a copolymer of an olefin and maleic anhydride, and a copolymer of styrene and maleic anhydride.

[0132] The polymeric organic compound may be, for example, at least one selected from the group consisting of α-olefins having a branch at the third carbon atom and having 5 or more carbon atoms (3,3-dimethylbutene-1,3-methylbutene-1,3-methylpentene-1,3-methylhexene-1,3-methylhexene-1, 3,5,5-trimethylhexene-1, etc.), vinylcycloalkane polymers (vinylcyclopentane, vinylcyclohexane, vinylnorbornane, etc.), polyalkylene glycols (polyethylene glycol, polypropylene glycol, etc.), poly(glycolic acid), cellulose, cellulose ester, and cellulose ether.

[0133] The phosphoric acid or phosphorous acid or metal salt thereof may be at least one selected from the group consisting of diphenyl phosphate, diphenyl phosphite, bis(4-tert-butylphenyl)phosphate, and metal salts of methylene bis(2,4-tert-butylphenyl)phosphate. Examples of sorbitol derivatives include bis(p-methylbenzylidene)sorbitol and bis(p-ethylbenzylidene)sorbitol.

[0134] The content of the nucleating agent may be 0.01 to 20 phr, 0.01 to 15 phr, 0.01 to 12 phr, 0.01 to 10 phr, 0.01 to 8 phr, 0.01 to 5 phr, 0.2 to 4.5 phr, 0.2 to 4 phr, or 0.5 to 3 phr. By setting the content of the nucleating agent within the above range, the crystallization rate can be increased and processability can be improved. For example, by increasing the crystallization rate in the cutting step for producing pellets in the preparation step, productivity and moldability can be further improved.

[0135] The melt strength agent is an additive for increasing the melt strength of the reaction product. Conventional melt strength agents may be used as long as they do not impair the effects of the present invention.

[0136] Specifically, the melt strength agent may include at least one selected from the group consisting of polyester, styrene-based polymer (such as acrylonitrile butadiene styrene or polystyrene), polysiloxane, organo-modified siloxane polymer, and maleic anhydride-ethylene propylene diene monomer conjugate (MAH-g-EPDM).

[0137] The content of the melt strength agent may be 0.01 to 20 phr, 0.01 to 15 phr, 0.01 to 12 phr, 0.01 to 10 phr, 0.01 to 8 phr, 0.01 to 5 phr, 0.2 to 4.5 phr, 0.2 to 4 phr, or 0.5 to 3 phr. When the content of the melt strength agent satisfies the above range, the desired effects of the present invention may be more easily exhibited.

[0138] The slip agent is an additive that enhances the slipperiness (ease of sliding) during extrusion and prevents the fiber surfaces from sticking together. Specifically, a conventional slip agent may be used as long as it does not impair the effects of the present invention. For example, the slip agent may be at least one selected from the group consisting of erucamide, olamide, and stearamide.

[0139] The content of the slip agent may be 0.01 to 20 phr, 0.01 to 15 phr, 0.01 to 12 phr, 0.01 to 10 phr, 0.01 to 8 phr, 0.01 to 5 phr, 0.2 to 4.5 phr, 0.2 to 4 phr, or 0.5 to 3 phr. When the content of the slip agent satisfies the above range, processability, productivity, and moldability may be further improved, which may be advantageous in terms of further achieving the desired effects of the present invention.

[0140] The biodegradable resin composition may further contain a crosslinking agent and / or a stabilizer as an additive.

[0141] The crosslinking agent is an additive for changing the properties of the PHA resin and increasing the molecular weight of the resin. Conventional crosslinking agents may be used as long as they do not impair the effects of the present invention.

[0142] For example, the crosslinking agent may be at least one selected from the group consisting of fatty acid esters, natural oils having epoxy groups (epoxidized natural oils), diallyl phthalate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, diethylene glycol dimethacrylate, and bis(2-methacryloxyethyl)phosphate.

[0143] The content of the crosslinking agent may be 0.01 phr to 20 phr, 0.01 phr to 15 phr, 0.01 phr to 12 phr, 0.01 phr to 10 phr, 0.01 phr to 8 phr, 0.01 phr to 5 phr, 0.2 phr to 4.5 phr, 0.2 phr to 4 phr, or 0.5 phr to 3 phr.

[0144] The stabilizer may be at least one selected from the group consisting of trimethyl phosphate, triphenyl phosphate, trimethylphosphine, phosphoric acid, and phosphorous acid.

[0145] The stabilizer content may be 0.01 phr to 20 phr, 0.01 phr to 15 phr, 0.01 phr to 12 phr, 0.01 phr to 10 phr, 0.01 phr to 8 phr, 0.01 phr to 5 phr, 0.2 phr to 4.5 phr, 0.2 phr to 4 phr, or 0.5 phr to 3 phr.

[0146] As used herein, additives may be in the form of, but are not limited to, a monomer, a polymer, or a copolymer.

[0147] According to another embodiment of the present invention, the biodegradable resin composition may further contain biomass.

[0148] By including biomass in the biodegradable resin composition, it is possible to enhance biodegradability and improve soil. That is, biomass has excellent biodegradability, is easily decomposed when not decomposed, serves as fertilizer, and improves soil strength, thereby producing a soil improvement effect.

[0149] The biomass may be used in an amount of 5 to 50% by weight, based on the total weight of the biodegradable resin composition. Specifically, the content of the biomass may be 10 to 48% by weight, 15 to 48% by weight, 20 to 45% by weight, 20 to 43% by weight, or 20 to 40% by weight, based on the total weight of the biodegradable resin composition. By ensuring that the biomass content satisfies the above ranges, biodegradability is further improved, soil improvement effects are achieved, and crosslinking strength with the PHA resin is improved, allowing the desired effects of the present invention to be more effectively achieved.

[0150] The biodegradable resin composition may have a melt flow index of 5 g / 10 minutes or more when measured at 190°C under 2.16 kg in accordance with ASTM D 1238. For example, the melt flow index of the biodegradable resin composition may be 5 g / 10 minutes or more, 6 g / 10 minutes or more, 7 g / 10 minutes or more, 7.5 g / 10 minutes or more, 8 g / 10 minutes or more, 9 g / 10 minutes or more, 5 g / 10 minutes to 30 g / 10 minutes, 6 g / 10 minutes to 20 g / 10 minutes, 7 g / 10 minutes to 15 g / 10 minutes, 7.5 g / 10 minutes to 10 g / 10 minutes, or 7.5 g / 10 minutes to 9.5 g / 10 minutes when measured at 190°C under 2.16 kg in accordance with ASTM D 1238.

[0151] The biodegradable resin composition may have a melt flow index of 30 g / 10 minutes or more when measured at 210°C and 2.16 kg in accordance with ASTM D1238. For example, the melt flow index of the biodegradable resin composition measured at 210°C and 2.16 kg in accordance with ASTM D1238 may be 45 g / 10 minutes or more, 50 g / 10 minutes or more, 53 g / 10 minutes or more, 55 g / 10 minutes or more, 59 g / 10 minutes or more, 65 g / 10 minutes or more, 80 g / 10 minutes or more, 90 g / 10 minutes or more, or 100 g / 10 minutes or more.

[0152] The melt flow index measured for the biodegradable resin composition according to ASTM D1238 may be measured for pellets prepared using the biodegradable resin composition according to ASTM D1238.

[0153] Specifically, the biodegradable resin composition is fed into a twin-screw compounder, kneaded, and melt-extruded to produce biodegradable pellets, and the melt flow index of the resulting pellets is measured in accordance with ASTM D 1238. More specifically, the biodegradable resin composition may be mixed by setting the screw rotation speed of the twin-screw compounder to 200 rpm and increasing the internal temperature from 50°C to 170°C, followed by melt-extrusion at a pressure of 12 bar and a temperature of 177°C using an underwater cutter system to produce biodegradable pellets.

[0154] The weight average molecular weight of the biodegradable resin composition may be 500,000 g / mol or less. For example, the weight average molecular weight of the biodegradable resin composition may be 450,000 g / mol or less, 400,000 g / mol or less, or 350,000 g / mol or less.

[0155] The biodegradable resin composition may have a glass transition temperature (Tg) of -35°C to 15°C, -25°C to 5°C, -20°C to 1°C, or -18°C to -5°C, a melting temperature (Tm) of 105°C to 200°C, 106°C to 195°C, 110°C to 180°C, or 113°C to 173°C, a crystallization temperature (Tc) of unmeasured, 50°C to 120°C, 65°C to 100°C, or 75°C to 95°C, and a cold crystallization temperature (Tcc) of unmeasured, 30°C to 120°C, 40°C to 110°C, or 50°C to 100°C, as measured by a differential scanning calorimeter (DSC).

[0156] The biodegradable resin composition may have a decomposition temperature (Td, weight loss 5%) measured by a thermogravimetric analyzer (TGA) of 220°C or higher, 230°C or higher, 240°C or higher, 250°C or higher, or 260°C or higher, 220°C to 275°C, 235°C to 273°C, 240°C to 300°C, 245°C to 285°C, 255°C to 280°C, 260°C to 275°C, or 263°C to 270°C.

[0157] biodegradable nonwoven fabric Another embodiment of the present invention provides a biodegradable nonwoven fabric comprising biodegradable fibers, the biodegradable fibers comprising a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units, and a flow agent.

[0158] The biodegradable nonwoven fabric may be an aggregate of biodegradable fibers. Details of the PHA and the fluidizing agent are as described above.

[0159] Specifically, the average length of the biodegradable fibers may be 100 mm or less. For example, the biodegradable fibers may be short fibers, and may have an average length of 85 mm or less, 70 mm or less, 60 mm or less, 55 mm or less, 45 mm or less, 35 mm or less, or 20 mm or less.

[0160] The average diameter of the biodegradable fibers may be 1 μm to 100 μm. For example, the average diameter of the biodegradable fibers may be 5 μm to 95 μm, 10 μm to 80 μm, 15 μm to 65 μm, or 20 μm to 50 μm.

[0161] The biodegradable fibers may be ultrafine fibers of 100 denier or less. For example, the fineness of each fiber of the biodegradable fibers constituting the biodegradable nonwoven fabric may be 0.1 denier to 100 denier, 0.5 denier to 100 denier, 1 denier to 100 denier, 5 denier to 95 denier, 10 denier to 90 denier, 10 denier to 80 denier, 20 denier to 70 denier, or 30 denier to 60 denier.

[0162] The elongation of the biodegradable fiber may be 10% or more, 12% or more, 15% or more, 20% or more, 25% or more, 32% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 1000% or less, 850% or less, 650% or less, 500% or less, 350% or less, 200% or less, 130% or less, 90% or less, 80% or less, or 75% or less.

[0163] The weight average molecular weight of the biodegradable fiber may be 300,000 g / mol or more, 500,000 g / mol or more, 10,000 g / mol to 5,000,000 g / mol, 20,000 g / mol to 4,000,000 g / mol, or 50,000 g / mol to 3,000,000 g / mol.

[0164] According to another embodiment of the present invention, the biodegradable nonwoven fabric may be prepared by a spunbond method. Specifically, the biodegradable nonwoven fabric may be a spunbond nonwoven fabric.

[0165] According to another embodiment of the present invention, a biodegradable nonwoven fabric is prepared from the biodegradable resin composition, and the biodegradable resin composition may have a melt flow index (MFI) of 5 g / 10 min or more when measured at 190°C and 2.16 kg in accordance with ASTM D1238.

[0166] Details of the biodegradable resin composition are as described above.

[0167] A biodegradable nonwoven fabric according to another embodiment of the present invention may be a biodegradable short-fiber nonwoven fabric prepared using the biodegradable resin composition.

[0168] According to another embodiment of the present invention, the biodegradable fiber may be a bicomponent fiber with a different cross section, or a bicomponent fiber of two or more or three or more components.

[0169] The heterogeneous cross-section fibers may be, but are not limited to, circular, elliptical, or polygonal in cross-section.

[0170] The biodegradable fiber may be of a sheath-core type having a core and a sheath, a side-by-side type, a sea-island type, or a segmented pie type.

[0171] In the sheath-core type, the cross section of the core and the cross section of the sheath may be different. For example, the cross section of the core may be circular and the cross section of the sheath may be doughnut-shaped, but this is not limitative.

[0172] The biodegradable fiber may also be a bicomponent fiber in which the sheath and core of the fiber portion of the fiber each contain different monofilament resins. For example, the fiber may be a ternary composite fiber in which the sheath is made of a single resin and the core is made of at least two resin components, or a ternary composite fiber in which the core is made of a single resin and the sheath is made of at least two resin components. The biodegradable fiber may also be a bicomponent fiber in which the sheath and core are each made of at least two resin components.

[0173] For example, the core may be made of a PHA resin, and the sheath may be made of a biodegradable resin. For example, the biodegradable resin may be at least one selected from the group consisting of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene succinate (PBS), polybutylene adipate (PBA), polybutylene succinate adipate (PBSA), polybutylene succinate terephthalate (PBST), polyhydroxybutyrate valerate (PHBV), polycaprolactone (PCL), polybutylene succinate adipate terephthalate (PBSAT), polybutylene ethylene adipate succinate (PBEAS), polybutylene ethylene succinate (PBES), and thermoplastic starch (TPS).

[0174] The weight ratio of the core to the sheath may be 5:95 to 95:5. For example, the weight ratio of the core to the sheath may be 5:95 to 85:15, 7:93 to 80:20, 10:90 to 75:25, or 10:90 to 70:30.

[0175] According to another embodiment of the present invention, the biodegradable nonwoven fabric may be electrostatically treated.

[0176] Electrostatic treatment is a method that can enhance the cohesion ability of nonwoven fabrics by charging them with static electricity. By subjecting nonwoven fabrics to electrostatic treatment, the fibers that make up the nonwoven fabric are forcibly charged, and nonwoven fabrics made of fibers with polarized charges can easily collect charged fine particles.

[0177] The electrostatic treatment process may be carried out using, but is not limited to, corona discharge, plasma charging, tribocharging, or water charging with high pressure water droplets.

[0178] To maximize the electrostatic effect, a charging agent may also be used, which may be, but is not limited to, a hindered amine charging agent.

[0179] According to another embodiment of the present invention, the biodegradable nonwoven fabric may further have a functional coating layer on at least one surface.

[0180] For example, the functional coating layer may be a hard coat layer or an antibacterial coating layer, and an adhesive layer may be interposed between the functional coating layer and the biodegradable nonwoven fabric.

[0181] At least one surface of the biodegradable nonwoven fabric may be subjected to ion or electrical surface treatment, such as, but not limited to, ion coating, ion probing, electroplating, or voltage plating.

[0182] The biodegradable nonwoven fabric may further contain one or more additives selected from the group consisting of a deodorant, an antibacterial agent, an inorganic filler, and a lubricant.

[0183] The deodorizing agent may be, for example, at least one metal oxide selected from the group consisting of titanium dioxide (TiO2), zinc oxide (ZnO), tin oxide (SnO2), zirconium dioxide (ZrO), and strontium titanate (SrTiO3), but is not limited thereto.

[0184] The deodorizing agent may be used in an amount of 0.01 to 20% by weight, based on the total weight of the biodegradable nonwoven fabric. For example, the deodorizing agent may be used in an amount of 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight, based on the total weight of the biodegradable nonwoven fabric.

[0185] The antibacterial agent may be at least one selected from the group consisting of nanosilver, nanocopper, nanozinc, and zeolite-based antibacterial agents, but is not limited thereto.

[0186] The antibacterial agent may be used in an amount of 0.01 to 20% by weight, based on the total weight of the biodegradable nonwoven fabric. For example, the antibacterial agent may be used in an amount of 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight, based on the total weight of the biodegradable nonwoven fabric.

[0187] The inorganic filler may include, but is not limited to, at least one selected from the group consisting of talc, barium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, zinc oxide, magnesium oxide, alumina, and silica.

[0188] The inorganic filler may have an average particle size of 0.01 μm to 2.0 μm. For example, the average particle size of the inorganic filler may be 0.01 μm to 2.0 μm, 0.05 μm to 2.0 μm, or 0.05 μm to 1.5 μm.

[0189] The inorganic filler may be used in an amount of 0.01 to 20% by weight, based on the total weight of the biodegradable nonwoven fabric, for example, 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight, based on the total weight of the biodegradable nonwoven fabric.

[0190] The lubricant may be a fatty acid ester, specifically, a glycerin fatty acid ester, a sorbitan fatty acid ester, a pyridoxine fatty acid ester, or a mixture of at least one selected from these, but is not limited thereto.

[0191] The lubricant may be employed in an amount of 0.01 to 20% by weight, based on the total weight of the biodegradable nonwoven fabric. For example, the lubricant may be employed in an amount of 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight, based on the total weight of the biodegradable nonwoven fabric.

[0192] Manufacturing method of biodegradable nonwoven fabric A method for producing a biodegradable nonwoven fabric according to another embodiment of the present invention includes melt-spinning pellets produced by melt-extruding a biodegradable resin composition, wherein the biodegradable resin composition comprises a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, and has a melt flow index (MFI) of 5 g / 10 min or greater when measured at 190°C and 2.16 kg in accordance with ASTM D1238.

[0193] Details of the biodegradable resin composition are as described above.

[0194] Specifically, in the method for producing a biodegradable nonwoven fabric according to another embodiment of the present invention, the biodegradable resin composition may be directly fed to an apparatus for melt spinning, or pellets prepared by melt extruding the biodegradable resin composition may be fed to an apparatus for melt spinning to prepare a biodegradable melt-blown nonwoven fabric.

[0195] More specifically, the biodegradable resin composition may be directly fed to an apparatus for melt spinning, or the biodegradable pellets may be extruded through a nozzle for melt spinning, cooled, and wound up on a roller to produce a biodegradable nonwoven fabric. In such cases, the process may be carried out using a spunbond melt spinning apparatus using an ejector, or a low-speed or high-speed staple fiber spinning machine, but is not limited thereto.

[0196] The melt spinning apparatus may also include a melting section, a nozzle section equipped with a filter, a draft section between the nozzle hole and a take-up roller, and a take-up section. Biodegradable fibers having desired physical properties can be produced by controlling the melt temperature of the melt spinning apparatus, the diameter of the nozzle hole, the length of the nozzle hole, the ratio of the length to the diameter of the nozzle hole, the size of the internal filter for the nozzle, the discharge amount from the nozzle, the length of the draft section, the spinning speed, the cooling temperature, and the take-up speed.

[0197] The biodegradable resin composition or pellets may be melt spun at a temperature of 150 to 230°C, 170 to 210°C, or 190 to 200°C.

[0198] The spinning speed may be 10 mpm to 5,000 mpm. For example, a spin-bonded nonwoven fabric may be produced at a spinning speed of 1,000 mpm to 5,000 mpm, 1,200 mpm to 4,500 mpm, or 1,500 mpm to 4,000 mpm. A staple fiber nonwoven fabric may be produced at a low spinning speed of 10 mpm to 200 mpm, 15 mpm to 180 mpm, or 20 mpm to 160 mpm, or at a high spinning speed of 500 mpm to 2,000 mpm, 600 mpm to 1,950 mpm, or 650 mpm to 1,700 mpm.

[0199] The spinning step may be carried out so that the basis weight of the biodegradable nonwoven fabric prepared as described above is 10 gsm to 500 gsm. For example, the spinning step may be carried out so that the basis weight of the biodegradable nonwoven fabric prepared in this manner is 12 gsm to 450 gsm, 15 gsm to 400 gsm, 20 gsm to 350 gsm, 20 gsm to 250 gsm, 25 gsm to 200 gsm, 25 gsm to 150 gsm, 25 gsm to 100 gsm, or 25 gsm to 50 gsm.

[0200] Furthermore, a drawing step may be further carried out after melt spinning. Specifically, when producing a staple fiber nonwoven fabric, further drawing may be carried out by cold drawing or hot drawing at a draw ratio of 1.1 or more. For example, the draw ratio may be 1.1 or more, 2.5 or more, 3.5 or more, 5 or more, 5.5 or more, 6 or more, 6.5 or more, or 7 or more.

[0201] In this way, by performing the drawing step following the spinning step, the diameter or length of the fibers in the biodegradable staple fiber nonwoven fabric can be more effectively controlled. Specifically, if the length or diameter of the biodegradable fibers is controlled only by the spinning or melt spinning step, productivity and processability may decrease.

[0202] According to another embodiment of the present invention, the method may further include melt-extruding the biodegradable resin composition at 150 to 200°C to prepare pellets.

[0203] Specifically, melt extrusion may be carried out at a pressure of 6 bar to 30 bar and a temperature of 150° C. to 200° C. For example, melt extrusion may be carried out using a single screw extruder or a twin screw extruder at a pressure of 7 bar to 28 bar or 8 bar to 26 bar and a temperature of 155° C. to 190° C. or 165° C. to 185° C.

[0204] Furthermore, before the melt extrusion step, a mixing step may be further carried out by raising the temperature to 50 to 170°C using a single-screw extruder or a twin-screw extruder.

[0205] Furthermore, after the melt-extrusion step, the molten extrudate may be cooled to 15°C or below, 10°C or below, or 6°C or below, and then cut into biodegradable pellets, but this is not limitative.

[0206] According to one embodiment of the present invention, the method may further include drying the pellets at 40 to 60° C. for 10 hours or more before the melt spinning step.

[0207] For example, before the melt spinning step, a step of drying the pellets at 40°C to 58°C or 42°C to 60°C for 11 hours or more or 12 hours or more may be further carried out.

[0208] Furthermore, the drying step may be carried out until the resin moisture content of the pellets is 2,000 ppm or less, 1,500 ppm or less, 1,100 ppm or less, 500 ppm or less, 300 ppm or less, 150 ppm or less, 100 ppm or less, 60 ppm or less, or 50 ppm or less, and may be carried out by hot air drying or dehumidifying drying, but is not limited to these.

[0209] According to another embodiment of the present invention, the step of spinning the biodegradable resin composition may be performed using a composite spinning apparatus. For example, the composite spinning apparatus may be a sheath-core composite spinning apparatus.

[0210] Specifically, the biodegradable resin composition may be directly supplied to the core or sheath of the sheath-core composite spinning device to produce a biodegradable fiber.

[0211] More specifically, the core or the sheath may be supplied with the biodegradable resin composition, or the core or the sheath may be supplied with a biodegradable resin containing at least one selected from the group consisting of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene succinate (PBS), polybutylene adipate (PBA), polybutylene succinate adipate (PBSA), polybutylene succinate terephthalate (PBST), polyhydroxybutyrate valerate (PHBV), polycaprolactone (PCL), polybutylene succinate adipate terephthalate (PBSAT), polybutylene ethylene adipate succinate (PBEAS), polybutylene ethylene succinate (PBES), and thermoplastic starch (TPS).

[0212] For example, the core may be filled with the biodegradable resin composition, and the sheath may be filled with a biodegradable resin containing at least one selected from the group consisting of PBAT (polybutylene adipate terephthalate), PLA (polylactic acid), PBS (polybutylene succinate), PBA (polybutylene adipate), PBSA (polybutylene succinate adipate), PBST (polybutylene succinate terephthalate), PHBV (polyhydroxybutyrate valerate), PCL (polycaprolactone), PBSAT (polybutylene succinate adipate terephthalate), PBEAS (polybutylene ethylene adipate succinate), PBES (polybutylene ethylene succinate), and TPS (thermoplastic starch).

[0213] The weight ratio of the raw materials supplied to the sheath relative to the core may be 5:95 to 95:5, 5:95 to 85:15, 7:93 to 80:20, 10:90 to 75:25, or 10:90 to 70:30.

[0214] Mode of Invention The present invention will be described in more detail below with reference to examples. However, the following examples are for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention. [Example]

[0215] Preparation of biodegradable resin composition Examples 1 to 9 The components shown in Table 1 were mixed and blended as shown in Table 2 (temperature: 120 to 180° C., screw rotation speed: 140 to 300 rpm) to prepare biodegradable resin compositions.

[0216] [Table 1]

[0217] [Table 2]

[0218] *phr (per hundred resin) refers to the unit of input amount of material added to 100 parts by weight of polymer (1 phr: 1 g of input amount for 100 g of polymer). [Test example] Test Example 1: Melt Flow Index The melt flow index (MFI; g / 10 min) of each of the biodegradable resin compositions prepared in Examples 1 to 9 and Comparative Examples 1 to 3 was measured at 190° C. and 2.16 kg in accordance with ASTM D1238. Test Example 2: Tg, Tm, Tc, and Tcc For each of the biodegradable resin compositions prepared in Examples 1 to 9 and Comparative Examples 1 to 3, the glass transition temperature (Tg) and melting temperature (Tm) were measured using differential scanning calorimetry (DSC).

[0219] Specifically, each biodegradable resin composition was placed in an aluminum pan of 5 mg to 20 mg, and the temperature was raised from 40°C to 180°C at 10°C / min using a differential scanning calorimeter, and then cooled to -50°C at the same rate of 10°C / min to obtain a heat flow curve, from which the glass transition temperature (Tg), melting temperature (Tm), crystallization temperature (Tc), and cold crystallization temperature (Tcc) were measured.

[0220] [Table 3]

[0221] As shown in Table 3, the biodegradable resin compositions of Examples 1 to 9 had excellent dispersibility, and their melt flow index (MFI), glass transition temperature (Tg), melting temperature (Tm), crystallization temperature (Tc), and cold crystallization temperature (Tcc) were within the desired ranges. In particular, when the biodegradable resin compositions were melt-extruded and spun to produce biodegradable fibers, the torque and pressure were lower than conventional methods and the viscosity characteristics were excellent, making it easier to control the process temperature and resulting in excellent processability and productivity. As a result, the biodegradable resin compositions of Examples 1 to 9 can be used to easily produce biodegradable nonwoven fabrics, particularly biodegradable spunbond nonwoven fabrics or biodegradable staple fiber nonwoven fabrics, and the quality of the biodegradable nonwoven fabrics produced can be further improved.

Claims

1. A biodegradable resin composition comprising a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, the composition having a melt flow index (MFI) of 5 g / 10 min or more as measured at 190°C and 2.16 kg in accordance with ASTM D1238.

2. The biodegradable resin composition according to claim 1, wherein the fluidizing agent comprises at least one selected from the group consisting of polystyrene-based polymers, polyacrylate-based polymers, and polystyrene-acrylate-based polymers.

3. 2. The biodegradable resin composition according to claim 1, wherein the fluidizing agent has a specific gravity of 0.7 to 1.8 and a weight average molecular weight of 1,500 g / mol to 8,000 g / mol.

4. 2. The biodegradable resin composition according to claim 1, wherein the fluidizing agent has a glass transition temperature (Tg) of 40°C or higher as measured by differential scanning calorimetry (DSC) and a melt flow index of 1,800 g / 10 min or higher as measured at 130°C and 12 kg in accordance with ASTM D1238.

5. The biodegradable resin composition according to claim 1, wherein the biodegradable resin composition comprises the fluidizing agent in an amount of 0.1 phr to 20 phr.

6. 2. The biodegradable resin composition according to claim 1, wherein the PHA resin contains 4-hydroxybutyric acid (4-HB) repeating units in an amount of 0.1% to 60% by weight.

7. 2. The biodegradable resin composition according to claim 1, wherein the PHA resin comprises a first PHA resin, the first PHA resin contains 15% by weight to 60% by weight of 4-hydroxybutyric acid (4-HB) repeating units, and the melt flow index (MFI) measured in accordance with ASTM D1238 at 165°C and 5 kg is 0.1 g / 10 min to 20 g / 10 min.

8. 2. The biodegradable resin composition according to claim 1, wherein the PHA resin comprises a second PHA resin, the second PHA resin contains 0.1% by weight to 30% by weight of 4-hydroxybutyric acid (4-HB) repeating units, and has a melt flow index of 0.1 g / 10 min to 15 g / 10 min when measured at 165°C and 5 kg in accordance with ASTM D1238.

9. 2. The biodegradable resin composition according to claim 1, wherein the biodegradable resin composition comprises at least one biodegradable resin selected from the group consisting of polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polybutylene succinate (PBS), 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).

10. The biodegradable resin composition according to claim 9, wherein the weight ratio of the PHA resin to the biodegradable resin is 1:99 to 99:

1.

11. The biodegradable resin composition according to claim 10, wherein the weight ratio of the PHA resin to the polylactic acid (PLA) resin is 20:80 to 70:

30.

12. 2. The biodegradable resin composition according to claim 1, wherein the biodegradable resin composition comprises at least one additive selected from the group consisting of pigments, dye absorbers, light absorbers, antioxidants, compatibilizers, extenders, nucleating agents, melt strength agents, and slip agents.

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

14. The biodegradable resin composition according to claim 1, wherein the biodegradable resin composition has a glass transition temperature (Tg) of -35°C to 15°C, a melting temperature (Tm) of 105°C to 200°C, a crystallization temperature (Tc) of 50°C to 120°C or not measured, and a cold crystallization temperature (Tcc) of 30°C to 125°C, as measured by a differential scanning calorimeter (DSC).

15. A biodegradable nonwoven fabric comprising biodegradable fibers, the biodegradable fibers comprising a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units, and a fluidizing agent.

16. 16. The biodegradable nonwoven fabric according to claim 15, wherein the biodegradable fibers have an average length of 100 mm or less and an average diameter of 1 μm to 100 μm.

17. The biodegradable nonwoven fabric according to claim 15, which is produced by a spunbond method.

18. 16. The biodegradable nonwoven fabric according to claim 15, which is produced from a biodegradable resin composition, and the biodegradable resin composition has a melt flow index (MFI) of 5 g / 10 min or more when measured at 190°C and 2.16 kg in accordance with ASTM D1238.

19. The biodegradable nonwoven fabric according to claim 15, wherein the biodegradable fiber is a composite fiber having different cross sections, or a composite fiber having two or more or three or more components.

20. The biodegradable nonwoven fabric according to claim 15, wherein the biodegradable fibers are of a sheath-core type having a core and a sheath, a side-by-side type, a sea-island type, or a segmented pie type.

21. A method for producing a biodegradable nonwoven fabric, comprising: melt-spinning a biodegradable resin composition or pellets produced by melt-extruding the biodegradable resin composition; The biodegradable resin composition comprises a polyhydroxyalkanoate (PHA) resin containing 4-hydroxybutyric acid (4-HB) repeating units and a fluidizing agent, and has a melt flow index (MFI) of 5 g / 10 min or more when measured at 190°C and 2.16 kg in accordance with ASTM D1238.

22. The method for producing a biodegradable nonwoven fabric according to claim 21, wherein the step of spinning the biodegradable resin composition is carried out using a sheath-core composite spinning apparatus.

23. The method for producing a biodegradable nonwoven fabric according to claim 22, wherein the sheath-core conjugate spinning apparatus comprises a core portion and a sheath portion, and the weight ratio of raw materials supplied to the core portion and the sheath portion is 5:95 to 95:

5.

24. The method for producing a biodegradable nonwoven fabric according to claim 23, wherein the biodegradable resin composition is supplied to the core.

Images