Resin composition and biodegradable resin molded article containing the same

Abstract

The present invention relates to a resin composition and a biodegradable resin molded article containing the same. The resin composition of the present invention can maintain the biodegradability inherent to polybutylene adipate terephthalate and polylactic acid, and can also achieve excellent mechanical properties.

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a biodegradable resin molded article containing the same. [Background technology]

[0002] Thermoplastic polymer resins have excellent mechanical and chemical properties and are used in a variety of fields, including drinking water containers, medical applications, food packaging paper, food containers, automotive moldings, and agricultural vinyl.

[0003] Thermoplastic polymer resins, especially polyethylene film, have excellent mechanical properties and are harmless to the human body. However, they can be continuously deformed when heated, so they are often used in hot sealing bags for food packaging and agricultural mulching films.

[0004] Hot sealing bags for food packaging are often used for vacuum packaging food products, and polyethylene film is often used because it can achieve excellent bonding strength even at low sealing temperatures.

[0005] Agricultural films are often used in mulching farming. Mulching refers to materials used to cover the soil surface when cultivating crops. Covering the top surface of the soil with various types of materials can block the growth of weeds and prevent pests, thereby reducing the use of pesticides. It also facilitates soil temperature regulation, promotes the growth of beneficial bacteria in the soil, prevents soil erosion, and maintains soil moisture.

[0006] Examples of such mulching materials include straw, grass and other crop leaves, and polyolefin-based films, with synthetic resins such as polyethylene films being commonly used.

[0007] However, as mentioned above, polyethylene film, which is often used in hot sealing bags for food packaging and mulching materials, does not decompose in the natural environment, limiting its reusability. In particular, it has recently become known that discarded plastics such as polyethylene film end up in the ocean, where they are broken down into very small microplastics by the ocean currents and sunlight.

[0008] It is now known that billions, or even tens of billions, of these microplastics are floating in the ocean, and these particles enter the bodies of marine life, accumulate in the ecosystem, and affect the entire food chain.

[0009] Therefore, research into alternative materials to the thermoplastics currently used is necessary.

[0010] To solve this problem, there have been active attempts in recent years to develop mulching films made from photodegradable or biodegradable polymers, but there are still problems in that the biodegradability is not sufficient and the mechanical properties are not as good as those of existing polyethylene films. Summary of the Invention [Problem to be solved by the invention]

[0011] The present specification aims to provide a resin composition having excellent biodegradability and excellent mechanical properties, and a biodegradable resin molded article containing the same. [Means for solving the problem]

[0012] The present specification provides a resin composition comprising polybutylene adipate terephthalate, polylactic acid, nanoclay, and an epoxy (meth)acrylate copolymer.

[0013] According to one embodiment of the present invention, the resin composition may contain about 1 to about 45 parts by weight of the polylactic acid per 100 parts by weight of the polybutylene adipate terephthalate.

[0014] According to one embodiment of the present invention, the resin composition may have a weight ratio of polybutylene adipate terephthalate:polylactic acid of about 6.5:3.5 to about 9.5:0.5.

[0015] According to one embodiment of the present invention, the resin composition may comprise about 0.01 to about 5 parts by weight of the nanoclay, or about 0.01 part by weight or more, or about 0.05 part by weight or more, or about 5 parts by weight or less, or about 3 parts by weight or less, or about 1 part by weight or less, or about 0.5 parts by weight or less, per 100 parts by weight of the polybutylene adipate terephthalate.

[0016] According to one embodiment of the present invention, the nanoclay may have a wetting coefficient value, more specifically, a wetting coefficient value for polybutylene adipate terephthalate and polylactic acid of about -1 to about 1.

[0017] According to one embodiment of the present invention, the nanoclay may be located within the composition at the interface between the polybutylene adipate terephthalate and the polylactic acid.

[0018] According to one embodiment of the present invention, the nanoclay may be a surface-modified nanoclay containing alkyl groups having 1 to 20 carbon atoms on the surface.

[0019] According to another embodiment of the present invention, the nanoclay may be a surface-modified nanoclay that is modified with an ammonium-based compound containing an alkyl group having 1 to 20 carbon atoms and contains residues of the ammonium-based compound containing an alkyl group having 1 to 20 carbon atoms on its surface.

[0020] According to one embodiment of the present invention, the epoxy (meth)acrylate copolymer may be a copolymer including (A) a repeating unit derived from an epoxy (meth)acrylate monomer, and (B) one or more repeating units selected from the group consisting of a repeating unit (b1) derived from a (meth)acrylate monomer, a repeating unit (b2) derived from a vinyl monomer, a repeating unit (b3) derived from an aromatic vinyl monomer, and a repeating unit (b4) derived from a nitrile monomer.

[0021] According to one embodiment of the present invention, the epoxy (meth)acrylate copolymer may be included in an amount of about 0.01 to about 15 parts by weight based on 100 parts by weight of the polybutylene adipate terephthalate.

[0022] According to one embodiment of the present invention, the epoxy (meth)acrylate copolymer may be included in an amount of about 1 to about 1000 parts by weight based on 100 parts by weight of the nanoclay.

[0023] According to one embodiment of the present invention, the resin composition may contain about 1 to about 50 parts by weight of an inorganic filler based on 100 parts by weight of the polybutylene adipate terephthalate and polylactic acid in total.

[0024] According to one embodiment of the present invention, the polylactic acid domains within the resin composition may have an average particle size of about 1 μm or less.

[0025] According to another aspect of the present invention, there is provided a biodegradable resin molded article comprising the above-mentioned resin composition. According to one embodiment of the present invention, the biodegradable resin molded article has an elongation value measured according to ASTM D638 of about 300% or more, about 400% or more, about 500% or more, or about 600% or more. The upper limit is not particularly significant, but it may be about 2000% or less, about 1700% or less, or about 1500% or less.

[0026] According to one embodiment of the present invention, the tensile strength of the biodegradable resin molded article, measured according to ASTM D638 standard, is about 1 MPa or more, or about 2 MPa or more, or about 5 MPa or more, or about 10 MPa or more, and although the upper limit is not particularly significant, it may be about 30 MPa or less, or about 25 MPa or less.

[0027] In the present invention, terms such as first and second are used to describe various components, and the terms are used only to distinguish one component from another.

[0028] Furthermore, the terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention.

[0029] The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0030] As used herein, terms such as "comprises," "comprises," or "having" are intended to describe one or more other features, numbers, steps, components, or combinations thereof that may be implemented, but do not exclude the possibility of one or more other features, numbers, steps, components, combinations thereof, or additional features.

[0031] Furthermore, in this specification, when a layer or element is referred to as being formed "on" or "on" a layer or element, it means that the layer or element is formed directly on the layer or element, or that other layers or elements may be additionally formed between the layers, on the object, or on the substrate.

[0032] Since the present invention can be modified in various ways and can have various forms, specific examples are exemplified and described in detail below, but it should be understood that this is not intended to limit the invention to the particular disclosed form, and that the invention also encompasses any modifications, equivalents, or alternatives falling within the spirit and technical scope of the invention.

[0033] As used herein, nanoclay refers to a nanomaterial containing clay minerals, with at least one dimension of length, width, or thickness measured in nanometers (about 1 to about 100 nm). Nanoclays primarily have a thickness measured in nanometers, have a plate-like morphology with a large aspect ratio of thickness to length or thickness to width, and consist of plate-like silicate particles stacked together.

[0034] The present invention will be described in detail below. The present specification provides a resin composition comprising polybutylene adipate terephthalate, polylactic acid, nanoclay, and an epoxy (meth)acrylate copolymer. The inventors of the present invention discovered that when a blending resin made by blending polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA) is used together with nanoclay and an epoxy (meth)acrylate copolymer, the compatibility of polybutylene adipate terephthalate and polylactic acid can be improved, thereby realizing excellent mechanical properties such as elongation, tensile strength, and elastic modulus of the blending resin, and thus completed the present invention.

[0035] A resin composition according to one embodiment of the present invention includes polybutylene adipate terephthalate (PBAT), polylactic acid, nanoclay, and an epoxy(meth)acrylate copolymer. The resin composition may contain about 1 to about 45 parts by weight of the polylactic acid per 100 parts by weight of the polybutylene adipate terephthalate (PBAT), or may contain about 1 part by weight or more, or about 5 parts by weight or more, or about 10 parts by weight or more, or about 45 parts by weight or less, or about 43 parts by weight or less.

[0036] Within the resin composition, the weight ratio of polybutylene adipate terephthalate to polylactic acid may be from about 6.5:3.5 to about 9.5:0.5, or about 6.5:3.5 or more, or about 6.9:3.1 or more, or about 7.5:2.5 or more, or about 9.5:0.5 or less, or about 9.1:0.9 or less. If the polylactic acid content is too low, the effect of improving the mechanical properties of polybutylene adipate terephthalate may not be achieved.If the polylactic acid content is too high, the hardness may increase, resulting in a problem of reduced elongation of the resin composition.In particular, when the resin composition is processed into a biodegradable film, the processability may decrease, making it difficult to achieve the required properties when used in applications such as mulching films.

[0037] Polyester resins have excellent mechanical and chemical properties and are used in a variety of industrial fields. Among them, polybutylene adipate terephthalate (PBAT) is a soft polyester that is biodegradable and has been attracting attention as a substitute for polyolefin polymers, which are mainly used in food packaging and agricultural films.

[0038] However, the mechanical properties of soft PBAT are somewhat insufficient for use alone in this application, so it is mainly used by blending it with hard polylactic acid (PLA), or by compounding PBAT alone with an organic filler such as carbon black.

[0039] When blending PBAT and PLA, a compatibilizer must be used because the compatibility between PBAT and PLA is very low.

[0040] Therefore, a resin composition according to one embodiment of the present invention contains nanoclay to improve the compatibility of these two resins.

[0041] Specific examples of nanoclays that may be used include, but are not limited to, montmorillonite, saponite, nontronite, laponite, beidelite, hectorite, vermiculite, magadite, kaolin, serpentine, and mica.

[0042] According to one embodiment of the present invention, the resin composition may contain about 0.01 to about 5 parts by weight of the nanoclay, or about 0.01 part by weight or more, or about 0.05 part by weight or more, or about 5 parts by weight or less, or about 3 parts by weight or less, or about 1 part by weight or less, or about 0.5 parts by weight or less, based on 100 parts by weight of the polybutylene adipate terephthalate.

[0043] If the amount of nanoclay is too small, the amount of nanoclay located at the interface between polybutylene adipate terephthalate and polylactic acid will be too small, which may result in a problem of not being able to improve compatibility.If the amount of nanoclay is too large, the nanoclay may be located within the resin matrix or domain, or the particles may aggregate, which may result in a problem of actually reducing the compatibility between polybutylene adipate terephthalate and polylactic acid.

[0044] According to one embodiment of the present invention, the nanoclay may have a wetting coefficient value with respect to polybutylene adipate terephthalate and polylactic acid of about -1 to about 1, or about -1 or greater, or about -0.5 or greater, or about -0.3 or greater, and about 1 or less, or about 0.5 or less, or about 0.3 or less.

[0045] Here, the wetting coefficient can be determined by calculating the surface energy between two materials using the contact angle between each material measured according to ASTM D5725 standard, and then calculating the interfacial energy based on the calculated surface energy.

[0046] Wetting coefficient, also known as spreading coefficient, is the difference between the work of adhesion and the work of cohesion at the interface when different materials come into contact.

[0047] The wetting coefficient value of particle C with respect to polymers A and B can generally be calculated by Young's equation as shown in Equation 1 below.

number

[0048] In the above formula 1, ω C is the wetting coefficient value of particle C for polymers A and B, and γ C-Pol B is the interfacial energy value between particle C and polymer B, and γ C-Pol A is the interfacial energy value between particle C and polymer A, and γ Pol A-Pol B is the interfacial energy value of polymer A and polymer B. The interfacial energy value between materials can be calculated using the harmonic mean equation or the geometric mean equation.

[0049] The harmonic mean equation can be used when the polarity of two substances, i.e., two phases, is similar and the polar component is similar to the non-polar component (or dispersive component), while the geometric mean equation can be used when the ionization potential of two substances, i.e., two phases, is similar and the polar component is more dominant than the non-polar component (or dispersive component).

[0050] The harmonic mean equation can be expressed as Equation 1-1 below, and the geometric mean equation can be expressed as Equation 1-2 below.

number

[0051] In the above formulas 1-1 and 1-2, γ 12 is the interfacial energy value between the first material and the second material, γ1 is the surface energy value of the first material, γ2 is the surface energy value of the second material, and γ1 d means the non-polar part of the surface energy value of the first material, and γ p means the polar part of the surface energy value of the first material, and γ2 d denotes the non-polar part of the surface energy value of the second material, and γ p denotes the polar part of the surface energy value of the second material.

[0052] For reference, the solid surface energy of a particle can be calculated from the contact angle with a reference liquid measured according to ASTM D5725 standard and the following Equation 2.

number

[0053] In the above formula 2, θ is the contact angle, and σ l is the surface energy value of the liquid phase, and σ s is the surface energy value of the solid phase, and σ l LW is the non-polar component of the surface energy value of the liquid phase, and σ s LW is the non-polar component of the surface energy value of the solid phase, and σ s + , σ s - are the polar components of the surface energy of the solid phase, and σ l + , σ l - are the polar components of the surface energy values ​​of the liquid phase, respectively.

[0054] Since three unknowns are used in Equation 2, each term in Equation 2 can be determined by using three standard liquids with known surface energy values ​​and measuring the contact angle between each standard liquid and the particle.

[0055] For more specific details, please refer to Eur.Polym.J, 2014, 60, 135-144.

[0056] However, the present invention is not necessarily limited to such a measurement method or calculation method, and the same method can be used to measure the surface energy value at each interface of nanoclay, polylactic acid, and polybutylene adipate terephthalate, and can also be used to measure the wetting coefficient.

[0057] According to one embodiment of the present invention, the nanoclay may be located within the composition at the interface between the polybutylene adipate terephthalate and the polylactic acid. In other words, the nanoclay having the above-mentioned wetting coefficient value is located at the interface between the polybutylene adipate terephthalate and the polylactic acid in the composition, thereby improving the compatibility between the polybutylene adipate terephthalate and the polylactic acid.

[0058] If the wetting coefficient value is too large or too small, the nanoclay may not be located at the interface between polymers in the composition, but may be dispersed within one of the polymer domains, which may result in a problem that the nanoclay may not contribute significantly to improving compatibility.

[0059] According to one embodiment of the present invention, the nanoclay may be a surface-modified nanoclay having an alkyl group on the surface having 1 to 20 carbon atoms, or 1 or more carbon atoms, or 5 or more carbon atoms, or 10 or more carbon atoms, or 20 or less carbon atoms.

[0060] The nanoclay whose surface has been modified as described above can have the interfacial properties described above and can contribute to improving the compatibility of polybutylene adipate terephthalate and polylactic acid.

[0061] If the number of carbon atoms in the alkyl group located on the surface of the nanoclay is too small or too large, the nanoclay may not be able to be located at the interface between polybutylene adipate terephthalate and polylactic acid, which may result in a problem that the aforementioned effect of improving the compatibility of polybutylene adipate terephthalate and polylactic acid is not fully achieved.

[0062] According to another embodiment of the present invention, the nanoclay may be a surface-modified nanoclay that is modified with an ammonium-based compound containing an alkyl group having 1 to 20 carbon atoms, or 1 or more carbon atoms, or 5 or more carbon atoms, or 10 or more carbon atoms, or 20 or less carbon atoms, and that contains, on its surface, a residue of an ammonium-based compound containing an alkyl group having 1 to 20 carbon atoms, or 1 or more carbon atoms, or 5 or more carbon atoms, or 10 or more carbon atoms, or 20 or less carbon atoms.

[0063] According to one embodiment of the present invention, the resin composition comprises an epoxy (meth)acrylate copolymer.

[0064] Here, the epoxy(meth)acrylate copolymer may refer to a homopolymer or copolymer containing a repeating unit derived from an epoxy alkyl(meth)acrylate monomer containing an epoxy group in the molecule.

[0065] In addition, the epoxy alkyl (meth)acrylate monomer may refer to, for example, an epoxy alkyl (meth)acrylate having an alkyl group with 1 to 10 carbon atoms, more specifically, having the following chemical formula: [ka]

[0066] In the above formula, R is an alkylene group having 1 to 10 carbon atoms, which may be linear or branched depending on the number of carbon atoms.

[0067] According to another example of the present invention, the resin composition may include a graft polymer in which the epoxy (meth)acrylate copolymer is used as a main chain and one or more of polybutylene adipate terephthalate (PBAT) and polylactic acid are linked to side chains of repeating units contained in an aromatic epoxy compound.

[0068] The structural feature of epoxy (meth)acrylate copolymers, which contain multiple epoxy groups in the molecule, is that it can increase the flexibility of the polymer chain, enhance the compatibility of polybutylene adipate terephthalate and polylactic acid, and increase the diffusion and entanglement of chains between the film interfaces when a film is produced using such a composition.

[0069] More specifically, the epoxy groups can react with the hydroxyl or carboxyl groups present in the polybutylene adipate terephthalate and / or polylactic acid molecules to extend the length of the polymer chain or form the graft copolymer.

[0070] As a result, the resin composition according to one aspect of the present invention can maintain excellent biodegradability and achieve very good mechanical properties.

[0071] According to one embodiment of the present invention, the epoxy (meth)acrylate copolymer may be a copolymer including (A) a repeating unit derived from an epoxy (meth)acrylate monomer, and (B) one or more repeating units selected from the group consisting of a repeating unit (b1) derived from a (meth)acrylate monomer, a repeating unit (b2) derived from a vinyl monomer, a repeating unit (b3) derived from an aromatic vinyl monomer, and a repeating unit (b4) derived from a nitrile monomer.

[0072] That is, the epoxy (meth)acrylate copolymer necessarily contains a repeating unit derived from an epoxy (meth)acrylate monomer, and may also contain one or more of the repeating units (b1) derived from a (meth)acrylate monomer (B), the repeating units (b2) derived from a vinyl monomer, the repeating units (b3) derived from an aromatic vinyl monomer, and the repeating units (b4) derived from a nitrile monomer.

[0073] The repeating unit derived from a (meth)acrylate monomer may refer to a repeating unit derived from an alkyl (meth)acrylate monomer containing an alkyl group having 1 to 5 carbon atoms.

[0074] The repeating unit (b2) derived from the vinyl monomer may refer to an alkene having 1 to 5 carbon atoms, that is, a repeating unit derived from an olefin monomer. The repeating unit derived from the aromatic vinyl monomer may refer to a repeating unit derived from a styrene monomer, more specifically, an aryl-alkyne monomer containing an aromatic ring in the molecule.

[0075] The repeating unit derived from the nitrile monomer may refer to an alkyne monomer containing a nitrile group in the molecule, or a (meth)acryloyl monomer containing a nitrile group in the molecule.

[0076] According to one embodiment of the present invention, the epoxy (meth)acrylate copolymer may be included in an amount of about 0.01 to about 15 parts by weight based on 100 parts by weight of the polybutylene adipate terephthalate.

[0077] In particular, the epoxy (meth)acrylate copolymer can interact with the nanoclay, and due to the interaction between the nanoclay and the epoxy (meth)acrylate copolymer, the epoxy (meth)acrylate copolymer can also be located at the interface between the polybutylene adipate terephthalate and the polylactic acid within the resin composition.

[0078] Due to these properties, the epoxy (meth)acrylate copolymer can simultaneously interact with polybutylene adipate terephthalate and polylactic acid within the resin composition, thereby further enhancing the effects of using the epoxy (meth)acrylate copolymer, and in particular, significantly increasing the compatibility between polybutylene adipate terephthalate and polylactic acid.

[0079] According to one embodiment of the present invention, the epoxy (meth)acrylate copolymer may be included in an amount of about 1 to about 1000 parts by weight based on 100 parts by weight of the nanoclay.

[0080] If the amount of epoxy (meth)acrylate copolymer used relative to the nanoclay is too small or too large, the above-mentioned synergistic effect may not be achieved.

[0081] The resin composition may contain only the polybutylene adipate terephthalate, polylactic acid, and aromatic epoxy compound as resin components. In other words, the resin composition according to one example of the present invention preferably does not contain any other resin or polymer component other than the polybutylene adipate terephthalate and polylactic acid.

[0082] In addition, the resin composition according to an embodiment of the present invention may further contain other additives. The additives may be any additives commonly used in molding resin compositions in the technical field to which the present invention pertains, i.e., in the field of thermoplastic polymers, without any particular limitations.

[0083] Additives may include heat stabilizers, UV stabilizers, and the like.

[0084] The additive may be contained in an amount of about 1 to about 30 parts by weight based on 100 parts by weight of the total of the polybutylene adipate terephthalate and polylactic acid.

[0085] The resin composition may contain about 1 to about 50 parts by weight, or about 10 to about 30 parts by weight, or about 15 to about 25 parts by weight of an inorganic filler relative to 100 parts by weight of the polybutylene adipate terephthalate and polylactic acid combined.

[0086] The inorganic filler can improve the mechanical properties and processability of the resin composition. If the inorganic filler is contained in an excessively small amount, the above-mentioned advantageous effects may not be achieved, whereas if the inorganic filler is contained in an excessively large amount, the mechanical properties and processability of the resin composition may be deteriorated.

[0087] According to one embodiment of the present invention, the average particle size of the polylactic acid domains in the resin composition may be about 1 μm or less, or about 800 nm or less, or about 700 nm or less, although the lower limit is not particularly significant, and may be about 100 nm or more.

[0088] Polybutylene adipate terephthalate and polylactic acid are not completely miscible with each other and therefore exist in separate states within the blending resin. Generally, polylactic acid can exist in a dispersed form with independent regions, i.e., domains, within the polybutylene adipate terephthalate matrix.

[0089] Therefore, in this specification, the diameter of a polylactic acid domain refers to the diameter measured when a spherical or amorphous polylactic acid domain formed in a polybutylene adipate terephthalate matrix is ​​approximated to a circle, more specifically, the diameter of a circle when an amorphous domain that appears when observing the surface or cross section of a resin composition is approximated to a circle. In particular, when the observed shape of the domain does not approximate a circle, the diameter refers to the longest straight line passing through the center point of the domain, i.e., the longest diameter.

[0090] The average domain diameter means the water average value of the domain diameter value described above.

[0091] Such an average domain diameter value can be measured and confirmed by analyzing an image of the resin composition obtained by SEM or the like using an image analysis program or the like.

[0092] In the resin composition according to one embodiment of the present invention, due to the high compatibility between polybutylene adipate terephthalate and polylactic acid, the domain size of polylactic acid dispersed in the polybutylene adipate terephthalate matrix is ​​very small, so that polylactic acid can be present in a form uniformly dispersed within the polybutylene adipate terephthalate.

[0093] According to another aspect of the present invention, there is provided a biodegradable resin molded article comprising the above-mentioned resin composition.

[0094] According to one embodiment of the present invention, the biodegradable resin molded article has an elongation value measured according to ASTM D638 of about 300% or more, about 400% or more, about 500% or more, or about 600% or more. The upper limit is not particularly significant, but it may be about 2000% or less, about 1700% or less, or about 1500% or less.

[0095] According to one embodiment of the present invention, the tensile strength of the biodegradable resin molded article measured according to ASTM D638 standard is about 10 MPa or more, or about 11 MPa or more, and although the upper limit is not particularly significant, it may be about 30 MPa or less, or about 25 MPa or less.

[0096] The biodegradable resin molded article according to one aspect of the present invention may be a biodegradable film.

[0097] Due to such excellent mechanical properties, the biodegradable resin molded article according to one embodiment of the present invention can be used for applications such as agricultural mulching films and food packaging materials. [Effects of the Invention]

[0098] The resin composition of the present invention can maintain the biodegradability inherent to polybutylene adipate terephthalate and polylactic acid, and can also achieve excellent mechanical properties. [Brief explanation of the drawings]

[0099] [Figure 1] 1 is a TEM image showing the morphology of a resin composition according to a comparative example. [Figure 2] 1 is an SEM image showing the morphology of a resin composition according to a comparative example. [Figure 3] 1 shows SEM images of the morphology of resin compositions according to comparative examples and examples of the present invention. [Figure 4] 1 shows TEM images of the morphology of resin compositions according to comparative examples and examples of the present invention. [Figure 5] 1 shows the results of measuring the mechanical properties of resin compositions according to comparative examples and examples of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0100] The functions and effects of the present invention will be described in more detail below with reference to specific examples of the present invention, however, these examples are presented only as examples of the invention and do not define the scope of the invention.

[0101] <Example> The polybutylene adipate terephthalate used was a product of Hengli Petrochemical Co., Ltd., with a melt index (MI, 190°C, 2.16 kg) value of 3.8 g / 10 min.

[0102] The polylactic acid used was a product of Nature Works, Inc., with a melt index (MI, 210° C., 2.16 kg) of 7.0 g / 10 min.

[0103] The composition ratio of polybutylene adipate terephthalate and polylactic acid was fixed at 80:20.

[0104] As nanoclays, C30B and C20A, products of BYK, were used.

[0105] As the epoxy (meth)acrylate copolymer (compatibilizer), Joncryl ADR 4468, a product of BASF, was used.

[0106] A resin composition was prepared according to the composition shown in Table 1. Specifically, polybutylene adipate terephthalate, polylactic acid, nanoclay, and optionally a compatibilizer were added according to the composition shown in the table below, and melt-mixed at approximately 190°C and 100 rpm using an internal batch mixer (Rheocomp mixer 600, MKE, Korea) to prepare the resin composition.

[0107] The prepared resin composition was made into analytical specimens using a compression molding machine (CH4386, Carver, 190°C).

[0108] Tensile strength and elongation measurements The tensile strength and elongation values ​​of the film were measured using a universal testing machine (manufacturer: GALDABINI, model name: QUASUR 50) according to ASTM D638 standard.

[0109] The specimens were prepared in the form of an ASTM D638 Type 5 Dogbone. [Table 1]

[0110] FIG. 1 is a TEM image showing the morphology of the resin compositions according to Comparative Examples 3 and 6. As shown in FIG.

[0111] Referring to FIG. 1, it can be seen that within the resin composition, the nanoclay component is located at the interface between the polybutylene adipate terephthalate and the polylactic acid.

[0112] FIG. 2 is an SEM image showing the morphology of the resin compositions according to Comparative Examples 3 to 8. As shown in FIG.

[0113] 2, it can be clearly seen that the domain particle size of polylactic acid is relatively small and uniform in the resin composition, which is thought to be the effect of adding nanoclay.

[0114] FIG. 3 is an SEM image showing the morphology of the resin compositions according to Comparative Example 2 and Examples 1 to 6.

[0115] 3, it can be clearly seen that the dispersion size of the polylactic acid domains becomes smaller when a mixture of nanoclay and compatibilizer is used compared to when a compatibilizer is used alone, and as the nanoclay content increases, the size of the polylactic acid domains becomes smaller and the boundaries between them become less clear. This is interpreted as being due to the increased compatibility between polylactic acid and polybutylene adipate terephthalate due to the interaction between the nanoclay and the compatibilizer.

[0116] FIG. 4 shows TEM images of the morphology of the resin compositions according to Comparative Example 2, Example 2, and Example 5.

[0117] Referring to FIG. 4, it can be seen that in the resin compositions of Examples 2 and 5, the nanoclay particles are mostly located at the interface between polylactic acid and polybutylene adipate terephthalate, and it can be clearly seen that the interface of the polylactic acid domain is unclear.

[0118] FIG. 5 shows the results of measuring the mechanical properties of the resin compositions according to Comparative Example 1 and Examples 1 to 6.

[0119] Referring to FIG. 5, it can be seen that the resin composition according to an embodiment of the present invention has excellent mechanical properties such as elongation and tensile strength.

Claims

1. Polybutylene adipate terephthalate, Polylactic acid, nanoclay, and Epoxy (meth)acrylate copolymers, Resin composition.

2. The resin composition according to claim 1, wherein the polylactic acid is contained in an amount of 1 to 45 parts by weight based on 100 parts by weight of the polybutylene adipate terephthalate.

3. 2. The resin composition according to claim 1, wherein the weight ratio of polybutylene adipate terephthalate to polylactic acid is from 6.5:3.5 to 9.5:0.

5.

4. For 100 parts by weight of the polybutylene adipate terephthalate, The resin composition according to claim 1, comprising 0.01 to 5 parts by weight of the nanoclay.

5. 2. The resin composition according to claim 1, wherein the nanoclay has a wetting coefficient value of -1 to 1 with respect to polybutylene adipate terephthalate and polylactic acid.

6. 2. The resin composition of claim 1, wherein the nanoclay is located at the interface of the polybutylene adipate terephthalate and the polylactic acid.

7. The resin composition according to claim 1, wherein the nanoclay is a surface-modified nanoclay containing an alkyl group having 1 to 20 carbon atoms on the surface.

8. The epoxy (meth)acrylate copolymer is (A) a repeating unit derived from an epoxy(meth)acrylate monomer, and The resin composition according to claim 1, wherein (B) is a copolymer containing one or more repeating units selected from the group consisting of (b1) repeating units derived from a (meth)acrylate monomer, (b2) repeating units derived from a vinyl monomer, (b3) repeating units derived from an aromatic vinyl monomer, and (b4) repeating units derived from a nitrile monomer.

9. 2. The resin composition according to claim 1, wherein the epoxy(meth)acrylate copolymer is contained in an amount of 0.01 to 15 parts by weight based on 100 parts by weight of the polybutylene adipate terephthalate.

10. The resin composition according to claim 1 , wherein the epoxy (meth)acrylate copolymer is contained in an amount of 1 to 1000 parts by weight based on 100 parts by weight of the nanoclay.

11. 2. The resin composition according to claim 1, comprising 1 to 50 parts by weight of an inorganic filler per 100 parts by weight of the polybutylene adipate terephthalate and the polylactic acid combined.

12. The resin composition according to any one of claims 1 to 11, Biodegradable resin molded product.

13. The biodegradable resin molded article according to claim 12, which has an elongation value of 300% or more as measured according to ASTM D638 standard.

14. The biodegradable resin molded article according to claim 12, which has a tensile strength of 1 MPa or more as measured according to ASTM D638 standard.

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