Crystal nucleating agent for biodegradable resins and biodegradable resin composition containing the same

Abstract

This invention relates to a nucleating agent for biodegradable resins and a biodegradable resin composition containing the same. The nucleating agent for biodegradable resins includes an aliphatic compound having three or more hydroxyethyl groups.

Description

Detailed description of the invention

[0001] [Technical field] This disclosure relates to a nucleating agent for controlling the crystallization rate of a biodegradable resin, and a biodegradable resin composition containing the nucleating agent.

[0002] [Background technology] Petroleum-based synthetic plastics cause problems such as the generation of microplastics, environmental pollution, and the generation of large amounts of waste. In particular, synthetic plastics are difficult to recycle, contribute to soil acidification, and pose a major threat to marine ecosystems.

[0003] To address these issues, biodegradable plastic products using polyhydroxyalkanoates (PHAs), which are aliphatic polyesters derived from plants, are attracting attention. Specifically, polyhydroxyalkanoates (PHAs) are naturally biodegradable and are environmentally friendly materials that can reduce the problem of waste disposal.

[0004] However, biodegradable resins such as PHA (polyhydroxyalkanoate) have a slow crystallization rate, meaning they take a long time to solidify after melting. This long solidification time can lead to decreased productivity and reduced mechanical properties of biodegradable resin products. For example, if a product manufactured using polyhydroxyalkanoate (PHA) is a film, the slow solidification rate makes it difficult to apply to film manufacturing lines, and the long cooling time reduces production efficiency. Furthermore, after film production, secondary crystallization of polyhydroxyalkanoate (PHA) can proceed over a certain period of time, potentially reducing the physical properties of the product, such as elongation and tensile strength.

[0005] Therefore, various technologies employing different nucleating agents have been proposed to control the crystallization rate of biodegradable resins such as polyhydroxyalkanoates (PHA) in order to ensure product productivity and mechanical properties. However, these proposed technologies still have limitations in producing products with faster crystallization rates (solidification rates) or superior mechanical properties.

[0006] Therefore, there is a need to develop nucleating agents that can more efficiently control the crystallization rate of biodegradable resins such as PHA (polyhydroxyalkanoate), thereby improving productivity during product manufacturing and enabling the production of products with excellent mechanical properties.

[0007] [Overview of the prefecture] [Problems the invention aims to solve] The object of this disclosure is to provide a nucleating agent for biodegradable resins that can optimize the crystallization rate of biodegradable resins such as PHA (polyhydroxyalkanoate), thereby improving productivity (processability) when manufacturing products using biodegradable resins, while maintaining excellent mechanical properties even after a certain period of time has elapsed, in order to solve the above-mentioned conventional problems.

[0008] Another object of this disclosure is to provide a biodegradable resin composition containing the above-mentioned nucleating agent for biodegradable resins, and a biodegradable film made from the above-mentioned biodegradable resin composition.

[0009] [Means for solving the problem] To achieve the above objective, the crystal nucleating agent of this disclosure is a crystal nucleating agent for biodegradable resins that comprises an aliphatic compound having three or more hydroxyethyl groups.

[0010] According to one embodiment of the present disclosure, the aliphatic compound is a compound represented by formula 1 or a derivative thereof.

[0011] [ka] R aThis is selected from the group consisting of hydrogen, substituted or unsubstituted C1-C5 alkyl groups, and substituted or unsubstituted C1-C5 hydroxyalkyl groups.

[0012] According to other embodiments of the present disclosure, the aliphatic compound may be at least one selected from the group consisting of trimethylolethane, trimethylolpropane, and tripentaerythritol.

[0013] Furthermore, this disclosure provides a biodegradable resin composition comprising the above-mentioned nucleating agent for biodegradable resins and polyhydroxyalkanoate (PHA).

[0014] According to one embodiment of the present disclosure, the polyhydroxyalkanoate (PHA) may contain repeating units derived from at least one monomer selected from the group consisting of 3-hydroxybutyric acid (3HB), 3-hydroxyhexanoic acid (3HH), 3-hydroxypropionic acid (3HP), 3-hydroxyvaleric acid (3HV), 4-hydroxybutyric acid (4HB), 4-hydroxyhexanoic acid (4HH), 4-hydroxypropionic acid (4HP), and 4-hydroxyvaleric acid (4HV).

[0015] According to other embodiments of the present disclosure, the polyhydroxyalkanoate (PHA) may contain 1 to 50% by weight of repeating units derived from 4-hydroxybutyric acid (4-HB) based on the total weight of the polyhydroxyalkanoate (PHA).

[0016] According to other embodiments of the present disclosure, the polyhydroxyalkanoate may include at least one selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer (P3HB-co-3HH), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer (P3HB-co-3HV), poly(3-hydroxybutyrate-co-3-hydroxypropionate) copolymer (P3HB-co-3HP), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer (P3HB-co-4HB), poly(3-hydroxybutyrate-co-4-hydroxyhexanoate) copolymer (P3HB-co-4HH), poly(3-hydroxybutyrate-co-4-hydroxyvalerate) copolymer (P3HB-co-4HV), and poly(3-hydroxybutyrate-co-4-hydroxypropionate) copolymer (P3HB-co-4HP).

[0017] According to other embodiments of the present disclosure, the polyhydroxyalkanoate (PHA) may be a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer (P3HB-co-4HB).

[0018] According to other embodiments of the present disclosure, the poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer (P3HB-co-4HB) may contain 1 wt% to 50 wt% of repeating units derived from 4-hydroxybutyric acid (4HB) and 50 wt% to 99 wt% of repeating units derived from 3-hydroxybutyric acid (3HB) with respect to the total weight of the poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer (P3HB-co-4HB).

[0019] According to other embodiments of the present disclosure, the content of the crystal nucleating agent for the biodegradable resin may be 0.01 to 30 parts by weight with respect to 100 parts by weight of the polyhydroxyalkanoate (PHA).

[0020] The present disclosure also provides a biodegradable film made from the above biodegradable resin composition.

[0021] The present disclosure also provides the use of an aliphatic compound having three or more hydroxyethyl groups as a crystal nucleating agent for a biodegradable resin, particularly when mixed with polyhydroxyalkanoate (PHA).

[0022] [Advantages of the Invention] The crystal nucleating agent for a biodegradable resin according to the present disclosure has a specific functional group and a specific structure (for example, the compound represented by the above formula 1 or its derivative) that affect the crystallization process of the biodegradable resin. As a result, the solidification rate in the molding process (for example, injection molding, extrusion molding, etc.) of the biodegradable resin can be increased compared to the conventional rate. In particular, the crystal nucleating agent for a biodegradable resin according to the present disclosure can significantly increase the crystallization rate (solidification rate) of polyhydroxyalkanoate (PHA) compared to conventional crystal nucleating agents for polyhydroxyalkanoate (PHA) such as cyanuric acid, talc, mannitol, xylitol, sorbitol, etc.

[0023] Therefore, when a product such as a biodegradable film is manufactured using a biodegradable resin composition containing the crystal nucleating agent for a biodegradable resin of the present disclosure, a product with significantly improved productivity (processability) and mechanical properties can be provided.

[0024] [Embodiments for Carrying Out the Invention] Hereinafter, the present disclosure will be described in detail. The present disclosure is not limited to the disclosure shown below, and can be modified into various forms without departing from the gist of the present disclosure.

[0025] In this specification, the term "comprising" is used to specifically identify a particular property, region, step, process, element, and / or component. Unless otherwise explicitly stated to the contrary, it does not exclude the presence or addition of other properties, regions, steps, processes, members, elements, and / or components.

[0026] The numerical values and expressions regarding the amounts of components, reaction conditions, etc. used here are within the range that can be understood even if modified by the term "substantially" unless otherwise specified. Crystal Nucleating Agent for Biodegradable Resin The biodegradable resin nucleating agent described herein has specific functional groups and / or specific structures that affect the crystallization rate of the biodegradable resin, thereby accelerating the crystallization rate (solidification rate) of the biodegradable resin compared to conventional methods. This will be described in detail below. Here, the crystallization rate of the biodegradable resin can be defined as the time required to cool the molten biodegradable resin to form crystals and establish crystal orientation. In other words, the crystallization rate of the biodegradable resin may refer to the solidification rate of the biodegradable resin.

[0027] The biodegradable resin nucleating agent according to this disclosure includes an aliphatic compound having three or more hydroxyethyl groups. The number of hydroxyethyl groups in the aliphatic compound is not particularly limited as long as it is three or more, but considering the crystallization rate of the biodegradable resin and the overall physical properties of the product, it may be 3 to 15, 3 to 13, 3 to 10, 3 to 8, 3 to 6, 3 to 5, or 3 to 4. For example, the above aliphatic compound may be an acyclic aliphatic compound having 3 to 10, 3 to 8, or 3 to 4 hydroxyethyl groups.

[0028] Specifically, the aliphatic compound may be a compound represented by the following formula 1 or a derivative thereof.

[0029] [ka] In formula 1, R a R is selected from the group consisting of hydrogen, substituted or unsubstituted C1-C5 alkyl groups, and substituted or unsubstituted C1-C5 hydroxyalkyl groups. Specifically, R a This may be, but is not limited to, a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, a substituted or unsubstituted propyl group, a substituted or unsubstituted hydroxymethyl group, or a substituted or unsubstituted hydroxyethyl group.

[0030] R aThe substituents in the alkyl and hydroxyalkyl groups are not particularly limited, but include deuterium, halogens (F, Cl, Br, I), hydroxyl group, cyano group, nitro group, amino group, amidino group, hydrazine group, hydrazone group, ester group, ketone group, carboxyl group, C1-C5 alkyl group, C1-C5 hydroxyalkyl group, C2-C5 alkenyl group, C2-C5 alkynyl group, C1-C5 alkoxy group, C3-C 10 Heteroaryl groups, and C6~C 20 It may be at least one selected from the group consisting of aryl groups.

[0031] A derivative of the compound represented by Formula 1 may be a compound obtained by chemically modifying a part of the compound represented by Formula 1. Such modification includes the introduction of functional groups, oxidation, reduction, and atom substitution.

[0032] For example, the aliphatic compound may be at least one selected from the group consisting of trimethylolethane (a compound represented by formula 1), trimethylolpropane (a compound represented by formula 1), and tripentaerythritol (a derivative of the compound represented by formula 1). Preferably, the aliphatic compound is trimethylolethane or trimethylolpropane.

[0033] By using aliphatic compounds as crystal nucleating agents for biodegradable resins, it is possible to accelerate the crystallization rate of biodegradable resins to a desired level while minimizing changes in the mechanical properties (e.g., tensile strength, elongation, etc.) of the biodegradable resin (biodegradable resin composition) and its products even after a certain period of time (e.g., 1 to 3 weeks).

[0034] The molecular weight of the aliphatic compound may, but is not limited to, 100-450 g / mol, 100-430 g / mol, 105-420 g / mol, 105-400 g / mol, 110-380 g / mol, 110-350 g / mol, 115-320 g / mol, 115-300 g / mol, 120-250 g / mol, 120-200 g / mol, or 120-150 g / mol.

[0035] Furthermore, the melting points of aliphatic compounds can, but are not limited to, 40-300°C, 45-280°C, 48-250°C, 50-230°C, 55-225°C, 70-220°C, 100-215°C, 150-210°C, or 180-210°C.

[0036] The biodegradable resin in which an aliphatic compound can function as a crystal nucleating agent is not particularly limited as long as it is a known biodegradable resin. Specifically, the biodegradable resin may include, but is not limited to, at least one selected from the group consisting of polyhydroxyalkanoate (PHA), polylactic acid (PLA), polybutylene adipate coterephthalate (PBAT), polybutylene succinate (PBS), polyglycolic acid (PGA), polycaprolactone (PCL), and thermoplastic starch (TPS). The biodegradable resin is preferably polyhydroxyalkanoate (PHA), and therefore, the crystal nucleating agent for the biodegradable resin is preferably a crystal nucleating agent for polyhydroxyalkanoate (PHA). Biodegradable resin composition The biodegradable resin composition of this disclosure comprises a nucleating agent for biodegradable resins and a polyhydroxyalkanoate (PHA).

[0037] The biodegradable resin nucleating agent contained in the biodegradable resin composition of this disclosure is an additive that improves (accelerates) the slow crystallization rate (solidification rate) of polyhydroxyalkanoate (PHA) by altering the crystallization morphology of polyhydroxyalkanoate (PHA) by melting and then cooling the polyhydroxyalkanoate (PHA). This biodegradable resin nucleating agent has substantially the same composition and properties as the biodegradable resin nucleating agent described above.

[0038] The content of the nucleating agent for biodegradable resins is not particularly limited, but it may be 0.01 to 30 parts by weight per 100 parts by weight of polyhydroxyalkanoate (PHA). Specifically, the content of the nucleating agent for biodegradable resins may be 0.03 to 28 parts by weight, 0.05 to 25 parts by weight, 0.08 to 23 parts by weight, 0.1 to 20 parts by weight, 0.3 to 18 parts by weight, 0.5 to 15 parts by weight, 0.8 to 13 parts by weight, 1 to 10 parts by weight, 1.3 to 8 parts by weight, 1.5 to 6 parts by weight, 1.8 to 5 parts by weight, 2 to 4.5 parts by weight, 2.3 to 4.3 parts by weight, 2.5 to 4 parts by weight, 2.7 to 3.8 parts by weight, 2.8 to 3.5 parts by weight, or 2.9 to 3.3 parts by weight per 100 parts by weight of polyhydroxyalkanoate (PHA). If the content of the biodegradable resin nucleating agent is within the above range, it is possible to provide a product with excellent mechanical properties while promoting the crystallization rate (solidification rate) of polyhydroxyalkanoate (PHA) to a desired level.

[0039] The polyhydroxyalkanoate (PHA) contained in the biodegradable resin composition according to this disclosure is a natural thermoplastic polyester resin that accumulates in microbial cells. Since polyhydroxyalkanoate (PHA) can be completely decomposed into carbon dioxide, water, and organic waste in soil and / or ocean, it can have excellent biodegradability without generating microplastics.

[0040] Polyhydroxyalkanoates (PHAs) may be obtained by mechanical or physical cell disruption, or by non-mechanical or chemical cell disruption. Specifically, polyhydroxyalkanoates (PHAs) may be copolymers obtained by polymerizing one or more monomers within the cells of a living microorganism using an enzyme catalyst.

[0041] Polyhydroxyalkanoates (PHAs) may contain repeating units derived from at least one monomer selected from the group consisting of 3-hydroxybutyric acid (3HB), 3-hydroxyhexanoic acid (3HH), 3-hydroxypropionic acid (3HP), 3-hydroxyvaleric acid (3HV), 4-hydroxybutyric acid (4HB), 4-hydroxyhexanoic acid (4HH), 4-hydroxypropionic acid (4HP), and 4-hydroxyvaleric acid (4HV).

[0042] Polyhydroxyalkanoates (PHAs) are classified into crystalline PHAs (cPHAs), semi-crystalline PHAs (scPHAs), and amorphous PHAs (aPHAs) depending on the type of monomer and the content of repeating units derived from the monomer. For example, polyhydroxyalkanoates (PHAs) can be classified into cPHAs, scPHAs, and aPHAs by controlling their crystallinity according to the content of repeating units derived from 4-hydroxybutyric acid (4HB) (4HB repeating units).

[0043] When a polyhydroxyalkanoate (PHA) contains repeating units derived from 4-hydroxybutyric acid (4HB) (4HB repeating units), the content of 4HB repeating units is not particularly limited, but may be 1 to 50% by weight relative to the total weight of the polyhydroxyalkanoate (PHA). Specifically, the content of 4HB repeating units may be 1 to 48% by weight, 1.2 to 45% by weight, 1.3 to 43% by weight, 1.5 to 42% by weight, 1.7 to 40% by weight, 1.8 to 38% by weight, 2 to 35% by weight, 2.1 to 33% by weight, 2.3 to 32% by weight, 2.5 to 30% by weight, 2.7 to 28% by weight, 2.9 to 27% by weight, 3 to 25% by weight, 4 to 24% by weight, 5 to 23% by weight, 6 to 20% by weight, 7 to 18% by weight, or 8 to 15% by weight relative to the total weight of the polyhydroxyalkanoate (PHA). If the content of 4HB repeating units in polyhydroxyalkanoate (PHA) is within the above range, the crystallization rate (solidification rate) of polyhydroxyalkanoate (PHA) can be rapidly controlled using a nucleating agent for biodegradable resins. As a result, products with excellent mechanical properties, processability, and productivity can be provided.

[0044] Specifically, the polyhydroxyalkanoate may include at least one selected from the group consisting of poly(3-hydroxybutyric acid-co-3-hydroxyhexanoic acid) copolymer (P3HB-co-3HH), poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) copolymer (P3HB-co-3HV), poly(3-hydroxybutyric acid-co-3-hydroxypropionic acid) copolymer (P3HB-co-3HP), poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB), poly(3-hydroxybutyric acid-co-4-hydroxyhexanoic acid) copolymer (P3HB-co-4HH), poly(3-hydroxybutyric acid-co-4-hydroxyvaleric acid) copolymer (P3HB-co-4HV), and poly(3-hydroxybutyric acid-co-4-hydroxypropionic acid) copolymer (P3HB-co-4HP).

[0045] The polyhydroxyalkanoate (PHA) is preferably a poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB) containing repeating units derived from 3-hydroxybutyric acid (3-HB) (3HB repeating units) and repeating units derived from 4-hydroxybutyric acid (4-HB) (4HB repeating units), in terms of processability, productivity, and mechanical properties of products manufactured from biodegradable resin compositions.

[0046] The content of 3HB repeating units and 4HB repeating units in poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB) is not particularly limited. Specifically, the content of 3HB repeating units can be 50-99% by weight, 55-99% by weight, 60-98% by weight, 65-98% by weight, 70-97% by weight, 75-97% by weight, 76-96% by weight, 77-95% by weight, 78-94% by weight, 79-93% by weight, 80-92% by weight, 81-91% by weight, or 82-90% by weight, relative to the total weight of poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB). Furthermore, the content of 4HB repeating units may be 1-50% by weight, 1-45% by weight, 2-40% by weight, 2-35% by weight, 3-30% by weight, 3-25% by weight, 4-24% by weight, 5-23% by weight, 6-22% by weight, 7-21% by weight, 8-20% by weight, 9-19% by weight, or 10-18% by weight, relative to the total weight of the poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB). By having the content of 3HB repeating units and 4HB repeating units within the above ranges, the interaction between the poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB) and the crystal nucleating agent for biodegradable resins is maximized, resulting in a biodegradable resin composition with a fast crystallization rate and excellent physical properties.

[0047] The weight-average molecular weight (Mw) of polyhydroxyalkanoates (PHAs) is not particularly limited, but can be 100,000-800,000 g / mol, 130,000-780,000 g / mol, 150,000-750,000 g / mol, 200,000-700,000 g / mol, 250,000-650,000 g / mol, 280,000-600,000 g / mol, 300,000-550,000 g / mol, or 320,000-500,000 g / mol.

[0048] The biodegradable resin composition relating to this disclosure may further contain known additives in addition to the biodegradable resin nucleating agent and polyhydroxyalkanoate (PHA). Specifically, it may be at least one selected from the group consisting of antioxidants, compatibilizers, slip agents, melt strength enhancers, ultraviolet absorbers, crosslinking agents, organic pigments, and inorganic pigments, but is not limited to these. The content of the additives may be adjusted as appropriate within a range that does not adversely affect the physical properties of the biodegradable resin composition and the product.

[0049] Furthermore, the biodegradable resin composition relating to this disclosure may further contain known biodegradable resins in addition to polyhydroxyalkanoates (PHA). The biodegradable resin is not particularly limited, but may include at least one selected from the group consisting of polylactic acid (PLA), polybutylene adipate-co-terephthalate (PBAT), polybutylene succinate (PBS), polyglycolic acid (PGA), polycaprolactone (PCL), and thermoplastic starch (TPS).

[0050] The biodegradable resin composition according to this disclosure may exhibit a remarkably fast solidification rate and excellent moldability. Specifically, the solidification rate of the biodegradable resin composition according to this disclosure, which is the time from melting to cooling, may be less than 4 minutes, 3 minutes 30 seconds or less, 3 minutes or less, 2 minutes 30 seconds or less, 2 minutes or less, 1 minute 30 seconds or less, 1 minute or less, 30 seconds or less, 20 seconds or less, or 15 seconds or less. Specifically, it may be, but is not limited to, 3 seconds to 3 minutes, 3 seconds to 2 minutes, 4 seconds to 1 minute, 4 seconds to 40 seconds, 5 seconds to 35 seconds, 5 seconds to 25 seconds, 5 seconds to 23 seconds, 6 seconds to 20 seconds, 6 seconds to 18 seconds, or 7 seconds to 15 seconds.

[0051] The biodegradable resin composition according to this disclosure may be in a state in which a nucleating agent for biodegradable resins and a polyhydroxyalkanoate (PHA) are physically or chemically mixed. Specifically, the biodegradable resin composition according to this disclosure may be a pellet for biodegradable resins obtained by melt-kneading a raw material composition containing a nucleating agent for biodegradable resins and a polyhydroxyalkanoate (PHA), extruding it into a strand, and then cooling, cutting, and drying it in an underwater cutting machine equipped with a solidification water tank.

[0052] Melt mixing can be carried out using a known single-thread extruder or double-thread extruder. The extrusion temperature (die extrusion temperature) used for melt mixing is not particularly limited and may be 145-165°C, 148-163°C, 150-160°C, 153-160°C, 155-160°C, or 155-158°C.

[0053] There are no particular restrictions on the temperature of the aquarium; specifically, it can be 20-30°C, 22-28°C, or 24-26°C.

[0054] After preparing the biodegradable resin composition of this disclosure in pellet form, it may be processed into various forms by known molding methods (e.g., injection molding, extrusion molding, compression molding, vacuum molding, pressure molding, blow molding, etc.). Specifically, the biodegradable resin composition of this disclosure may be processed into the form of a film, sheet, straw, container, cup, spoon, fork, knife, tray, mesh, or bottle. Biodegradable film The biodegradable film of this disclosure is manufactured from the biodegradable resin composition described above. Specifically, since the biodegradable film of this disclosure is manufactured from a biodegradable resin composition containing the biodegradable resin nucleating agent described above, its mechanical properties remain virtually unchanged over time, it has excellent physical properties, and productivity is greatly improved.

[0055] The biodegradable film relating to this disclosure, when analyzed using a differential scanning calorimetry (DSC), has a first melting temperature (T m1 ), second melting temperature (T m2 ), and glass transition temperature (Tc ) can be shown.

[0056] The first melting temperature (T m1 ) of the biodegradable film according to the present disclosure is specifically, for example, 130 to 150 ° C, 132 to 148 ° C, 134 to 146 ° C, 136 to 144 ° C, 138 to 142 ° C, or 140 to 141 ° C, but is not limited thereto.

[0057] Also, the second melting temperature (T m2 ) of the biodegradable film according to the present disclosure is specifically, for example, 151 to 170 ° C, 152 to 168 ° C, 154 to 166 ° C, 156 to 164 ° C, 158 to 162 ° C, or 160 to 161 ° C, but is not limited thereto.

[0058] The glass transition temperature (T c ) of the biodegradable film according to the present disclosure is specifically, for example, 55 to 85 ° C, 57 to 83 ° C, 59 to 81 ° C, 60 to 80 ° C, 62 to 78 ° C, 64 to 76 ° C, or 65 to 75 ° C, but is not limited thereto.

[0059] On the other hand, the biodegradable film according to the present disclosure can have a breaking strength measured in accordance with ASTM D 882 of 30 MPa or more. Specifically, the breaking strength of the biodegradable film may be 31 MPa or more, 32 MPa or more, 33 MPa or more, 34 MPa or more, or 35 MPa or more (for example, 30 to 40 MPa, 31 to 38 MPa, 32 to 37 MPa, 33 to 36 MPa, 34 to 35 MPa), but is not limited thereto.

[0060] Also, the elongation of the biodegradable film according to the present disclosure measured in accordance with ASTM D 882 may be 5 to 40%. Specifically, the elongation rate of the biodegradable film may be 5 to 38%, 6 to 35%, 6 to 32%, 7 to 30%, 7 to 25%, 8 to 20%, 8 to 18%, 9 to 15%, 9 to 13%, or 10 to 12%.

[0061] The thickness of the biodegradable film relating to this disclosure is not particularly limited, but may be 5-250 μm, 5-200 μm, 5-150 μm, 5-100 μm, 10-90 μm, 15-80 μm, 20-70 μm, 25-65 μm, 30-60 μm, 40-55 μm, or 50-55 μm.

[0062] The biodegradable film disclosed herein has excellent mechanical properties and productivity, and is also environmentally friendly, making it suitable for use in various fields.

[0063] Mode of the invention The present disclosure will be further described below with reference to examples, but the scope of the present disclosure should not be limited by the examples shown below.

[0064] [Preparation Examples 1-5] The compounds shown in Table 1 below were prepared as crystal nucleation agents.

[0065] [Table 1]

[0066] [Example 1] (1) Preparation of biodegradable resin composition A nucleating agent (trimethylolethane) was prepared using 3 parts by weight (3 phr: parts per hundred rubber) of the same material as in Preparation Example 1, with 100 parts by weight of P3HB-co-4HB resin (CJ Cheiljedan, S1000P) containing approximately 6% by weight of 4HB repeating units. The P3HB-co-4HB resin and the nucleating agent from Preparation Example 1 were placed in a twin-screw extruder (Bouteck) for kneading and strand formation. Subsequently, the mixture was cut to prepare a biodegradable resin composition (biodegradable resin pellets). In this process, the twin-screw extruder was configured with an L / D ratio of 50 and a diameter of 17φ. Furthermore, in the twin-screw extruder, the hopper zone temperature was maintained at 100°C, the discharge die temperature at 155°C, and the water tank temperature at 25°C. (2) Preparation of biodegradable film The biodegradable resin composition prepared above was melt-extruded and then introduced using a roll-to-roll method to prepare a biodegradable film with a thickness of 50 μm. The roll temperature in the roll-to-roll method was maintained at approximately 38°C.

[0067] [Example 2] A biodegradable resin composition (biodegradable resin pellets) and a biodegradable film were prepared in the same manner as in Example 1, except that the nucleating agent used in Preparation Example 1 was replaced with the nucleating agent used in Preparation Example 2 (trimethylolpropane).

[0068] [Comparative Example 1] A biodegradable resin composition (biodegradable resin pellets) and a biodegradable film were prepared following the same procedure as in Example 1, except that the nucleating agent (cyanuric acid) from Preparation Example 3 was used instead of the nucleating agent from Preparation Example 1.

[0069] [Comparative Example 2] Except for not using the nucleating agent from Preparation Example 1 (i.e., using only P3HB-co-4HB resin), biodegradable resin compositions (biodegradable resin pellets) and biodegradable films were prepared according to the same procedure as in Example 1.

[0070] [Comparative Example 3] A biodegradable resin composition (biodegradable resin pellets) and a biodegradable film were prepared following the same procedure as in Example 1, except that the crystal nucleating agent (xylitol) from Preparation Example 4 was used instead of the crystal nucleating agent from Preparation Example 1.

[0071] [Comparative Example 4] A biodegradable resin composition (biodegradable resin pellets) and a biodegradable film were prepared following the same procedure as in Example 1, except that the nucleating agent (D-sorbitol) from Preparation Example 5 was used instead of the nucleating agent from Preparation Example 1.

[0072] [Comparative Example 5] A biodegradable resin composition (biodegradable resin pellets) and a biodegradable film were prepared following the same procedure as in Example 1, except that the crystal nucleating agent (succinate amide) from Preparation Example 6 was used instead of the crystal nucleating agent from Preparation Example 1.

[0073] [Test Example 1] Measurement of Solidification Rate In Examples 1 and 2, and Comparative Examples 1 to 5, the strands discharged from the discharge die after mixing were immediately placed in a 25°C water bath, and the time until they could no longer be stretched in the water bath was measured.

[0074] [Test Example 2] Evaluation of film-forming suitability In Test Example 1, after measuring the solidification rate, the suitability for film formation was evaluated according to the following criteria. ◎: Solidification speed within 20 seconds ○: Solidification rate within 1 minute △: Solidification rate within 2 minutes ×: Solidification rate of 2 minutes or more

[0075] [Test Example 3] T m , T c , T cc ΔH c Analysis The above biodegradable resin compositions (biodegradable resin pellets) or biodegradable films prepared in Examples 1-2 and Comparative Examples 1-5 were measured using a known differential scanning calorimetry (DSC) to determine their melting temperature (T m ), crystallization temperature (T c ), cooling crystallization temperature (T cc ), and heat quantity (ΔH c The temperature was measured. During this process, the temperature was increased from -50°C to 190°C at a rate of 10°C / min, and then decreased from 190°C to -50°C at a rate of 10°C / min, and DSC measurements were performed.

[0076] [Test Example 4] Analysis of fracture strength and elongation The tensile strength and elongation of each biodegradable resin composition (biodegradable resin pellet) or biodegradable film prepared in Examples 1 and 2, and Comparative Examples 1 to 5, were measured using a Universal Test Machine (UTM). Specifically, each biodegradable resin composition (biodegradable resin pellet) or biodegradable film was pressurized using a hot press (set temperature 160°C) to prepare test specimens (film test specimens) with a width of 15 mm, a length of 100 mm, and a thickness of 200 μm. These specimens were left at room temperature for 1 day, 7 days, and 14 days, respectively, and then tensile tests were performed according to ASTM D 882 (crosshead speed: 200 mm / min, width: 15 mm, gauge length: 50 mm) to measure the tensile strength and elongation.

[0077] The results of the test examples are shown in Tables 2 and 3 below.

[0078] [Table 2]

[0079] [Table 3] Referring to Tables 2 and 3 above, Examples 1 and 2 of this disclosure have a solidification rate of 35 seconds or less (in particular, Example 1 has a very fast solidification rate of 7 to 15 seconds), excellent film productivity (manufacturing efficiency), rapid completion of polyhydroxyalkanoate (PHA) crystallization, minimal changes over time, and maintenance of the film's mechanical properties (see the values ​​of tensile strength and elongation after 1, 7, and 14 days).

[0080] In contrast, Comparative Example 2, which did not use a nucleating agent, solidified in more than 5 minutes, resulting in reduced film manufacturing efficiency and significant deterioration of the film's mechanical properties over time. Furthermore, in Comparative Examples 1, 3, 4, and 5, which used known nucleating agents instead of the nucleating agent described herein, the productivity (production efficiency) of the film decreased, and the mechanical properties of the film deteriorated.

Claims

1. A nucleating agent for biodegradable resins, comprising an aliphatic compound having three or more hydroxyethyl groups.

2. The biodegradable resin nucleating agent according to claim 1, wherein the aliphatic compound is a compound represented by the following formula 1 or a derivative thereof. 【Chemistry 1】 In formula 1, R ａ C is hydrogen, substituted or unsubstituted. １ ~C ５ Alkyl alkyl groups, and substituted or unsubstituted C １ ~C ５ Selected from the group consisting of hydroxyalkyl groups.

3. The biodegradable resin nucleating agent according to claim 1, wherein the aliphatic compound is at least one selected from the group consisting of trimethylolethane, trimethylolpropane, and tripentaerythritol.

4. A biodegradable resin nucleating agent according to claim 1, Contains polyhydroxyalkanoate (PHA) and Biodegradable resin composition.

5. The biodegradable resin composition according to claim 4, wherein the polyhydroxyalkanoate (PHA) comprises repeating units derived from at least one monomer selected from the group consisting of 3-hydroxybutyric acid (3HB), 3-hydroxyhexanoic acid (3HH), 3-hydroxypropionic acid (3HP), 3-hydroxyvaleric acid (3HV), 4-hydroxybutyric acid (4HB), 4-hydroxyhexanoic acid (4HH), 4-hydroxypropionic acid (4HP), and 4-hydroxyvaleric acid (4HV).

6. The biodegradable resin composition according to claim 4, wherein the polyhydroxyalkanoate (PHA) contains 1 to 50% by weight of repeating units derived from 4-hydroxybutyric acid (4HB) based on the total weight of the polyhydroxyalkanoate (PHA).

7. The aforementioned polyhydroxyalkanoates include poly(3-hydroxybutyrate-co-3-hydroxyhexanoic acid) copolymer (P3HB-co-3HH), poly(3-hydroxybutyrate-co-3-hydroxyvaleric acid) copolymer (P3HB-co-3HV), poly(3-hydroxybutyrate-co-3-hydroxypropionic acid) copolymer (P3HB-co-3HP), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer (P3H The biodegradable resin composition according to claim 4, comprising at least one selected from the group consisting of B-co-4HB, poly(3-hydroxybutyrate-co-4-hydroxyhexanoic acid) copolymer (P3HB-co-4HH), poly(3-hydroxybutyrate-co-4-hydroxyvaleric acid) copolymer (P3HB-co-4HV), and poly(3-hydroxybutyrate-co-4-hydroxypropionic acid) copolymer (P3HB-co-4HP).

8. The biodegradable resin composition according to claim 4, wherein the polyhydroxyalkanoate (PHA) is a poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB).

9. The biodegradable resin composition according to claim 8, wherein the poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB) contains 1% to 50% by weight of repeating units derived from 4-hydroxybutyric acid (4HB) and 50% to 99% by weight of repeating units derived from 3-hydroxybutyric acid (3HB), based on the total weight of the poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer (P3HB-co-4HB).

10. The biodegradable resin composition according to claim 4, wherein the content of the biodegradable resin nucleating agent is 0.01 to 30 parts by weight per 100 parts by weight of the polyhydroxyalkanoate (PHA).

11. A biodegradable film made from the biodegradable resin composition described in claim 4.

12. When mixed with polyhydroxyalkanoate (PHA), it can be used as a crystal nucleating agent for biodegradable resins, specifically aliphatic compounds having three or more hydroxyethyl groups.

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