Resin composition and molded article

Abstract

The present invention relates to a biodegradable resin composition, and more particularly to a biodegradable resin composition having excellent mechanical properties and improved compatibility by applying a chemical compatibilizer to improve the compatibility between different types of biodegradable resins, and to a biodegradable molded article molded from the composition.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0064184, filed May 25, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a resin composition and a biodegradable molded article molded therefrom. [Background technology]

[0003] Thermoplastic resins have excellent mechanical and chemical properties and are used in a variety of fields, including drinking water containers, medical applications, food wrapping paper, food containers, automotive molded parts, and agricultural vinyl.

[0004] Among these, polyethylene films and the like are primarily used for hot sealing bags for packaging food and agricultural mulching films because they have excellent mechanical properties, are harmless to the human body, and can be continuously deformed when heated.

[0005] Hot sealing bags for food packaging are widely used for vacuum packaging food and the like, and are mainly made of polyethylene film, which can achieve excellent bonding strength even at low sealing temperatures.

[0006] Agricultural mulching films are mainly used in mulching farming. Mulching is a material that covers the surface of the soil when cultivating agricultural crops. By covering the top surface of the soil with various materials, it is possible to block the growth of weeds and prevent diseases and pests, thereby reducing the use of pesticides. It also makes it easy to regulate the temperature of the soil, promotes the proliferation of beneficial bacteria in the soil, prevents soil erosion, and maintains soil moisture. Such mulching materials can include straw, grass and other crop leaves, polyolefin films, and the like, and generally synthetic resins such as polyethylene films are mainly used.

[0007] However, polyethylene film does not decompose in the natural environment, and there is a limit to how much it can be reused. In particular, a recent problem has been the phenomenon in which discarded plastics such as polyethylene film flow into the ocean, where they are broken down into very small microplastics by the ocean's circulation and sunlight. It is known that countless amounts of such microplastics, numbering in the billions to tens of billions, float in the ocean, and these microplastics flow into the bodies of marine organisms, accumulating in the ecosystem and affecting the entire food chain.

[0008] For this reason, interest in biodegradable plastics has been growing recently. Among them, polybutylene adipate terephthalate (hereinafter referred to as PBAT) and polylactic acid (hereinafter referred to as PLA) have attracted attention as biodegradable plastics, and efforts are being made to improve the compatibility of PBAT and PLA in biodegradable resin compositions that contain them simultaneously.

[0009] Compatibilizers for biodegradable resin compositions containing PBAT and PLA are divided into physical compatibilizers and chemical compatibilizers according to their operating principle. Typical physical compatibilizers are those that use copolymers containing PBAT or PLA. However, when using such physical compatibilizers, there is a problem that the mechanical properties are reduced because the physical compatibilizer plays a role similar to that of a plasticizer.

[0010] Meanwhile, Korean Patent Publication No. 10-2045863 (Patent Document 1) discloses a biodegradable polyester film containing a copolymer containing an epoxy group and based on styrene, an acrylic acid ester, and / or a methacrylic acid ester. When the copolymer disclosed in Patent Document 1 is used as a compatibilizer for PBAT and PLA, when used in a certain amount or more, not only PBAT-g-PLA is formed at the interface between PBAT and PLA, but also a large amount of PBAT-g-PBAT and / or PLA-g-PLA is formed in each resin, causing a problem of a sudden increase in viscosity of the resin composition. Such a sudden increase in viscosity is difficult to control during processing of the resin composition, which limits the expansion of the use of the resin composition. Therefore, it is important to secure a compatibilizer that can maintain performance as a chemical compatibilizer in a biodegradable resin composition containing different biodegradable resins and can control the increase in viscosity within an appropriate range to ensure processability. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] KR10-2045863 B1 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been devised to solve the problems of the prior art, and in a biodegradable resin composition containing different types of biodegradable resins, a chemical compatibilizer is applied to improve compatibility between the different types of biodegradable resins, thereby improving compatibility and improving mechanical properties.

[0013] In other words, an object of the present invention is to provide a biodegradable resin composition containing different types of biodegradable resins, in which the compatibility is improved by a chemical compatibilizer and the mechanical properties are improved.

[0014] Another object of the present invention is to provide a resin composition that can be expanded to various formulations and applications by adjusting the structure of an acrylic copolymer, which is a compatibilizer for different types of biodegradable resins, and thereby suppressing a sudden increase in viscosity and improving compatibility even when the compatibilizer is used in the same content as the copolymer disclosed in Patent Document 1.

[0015] Another object of the present invention is to provide a molded article which is produced from the resin composition and exhibits biodegradability. [Means for solving the problem]

[0016] In order to solve the above problems, the present invention provides a resin composition and a molded article.

[0017] (1) The present invention provides a resin composition comprising a first biodegradable resin, a second biodegradable resin, and at least one of an acrylic copolymer and a compatibilizing part formed from the acrylic copolymer, wherein the acrylic copolymer comprises a methyl (meth)acrylate monomer unit, a (meth)acrylate monomer unit containing an epoxy group, and an alkyl (meth)acrylate monomer unit having 2 to 10 carbon atoms, and the resin composition comprises 15% by weight or more and 60% by weight or less of the (meth)acrylate monomer unit containing an epoxy group.

[0018] (2) The present invention provides a resin composition according to the above (1), wherein the first biodegradable resin contains an aliphatic polyester unit and an aromatic polyester unit.

[0019] (3) The present invention provides a resin composition according to the above (1) or (2), wherein the first biodegradable resin contains polybutylene adipate terephthalate.

[0020] (4) The present invention provides a resin composition according to any one of the above (1) to (3), wherein the second biodegradable resin contains polylactic acid.

[0021] (5) The present invention provides a resin composition according to any one of (1) to (4), wherein the resin composition contains the second biodegradable resin in an amount of 1 part by weight or more and 50 parts by weight or less per 100 parts by weight of the first biodegradable resin.

[0022] (6) The present invention provides a resin composition according to any one of (1) to (5) above, comprising at least one of the acrylic copolymer and the compatibilizing part formed from the acrylic copolymer in an amount of 0.01 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the first biodegradable resin.

[0023] (7) The present invention provides a resin composition according to any one of the above (1) to (6), wherein the acrylic copolymer contains 25% by weight or more and 65% by weight or less of methyl (meth)acrylate monomer units, 15% by weight or more and 60% by weight or less of (meth)acrylate monomer units containing an epoxy group, and 5% by weight or more and 30% by weight or less of alkyl (meth)acrylate monomer units having 2 to 10 carbon atoms.

[0024] (8) The present invention provides the resin composition according to any one of the above (1) to (7), wherein the acrylic copolymer has an epoxy equivalent weight (EEW) of 200 g / eq or more and 800 g / eq or less.

[0025] (9) The present invention provides the resin composition according to any one of the above (1) to (8), wherein the acrylic copolymer has a weight average molecular weight of 10,000 or more and 100,000 or less.

[0026] (10) The present invention provides the resin composition according to any one of the above (1) to (9), wherein the acrylic copolymer has a glass transition temperature of 45° C. or higher and 85° C. or lower.

[0027] (11) The present invention provides a resin composition according to any one of the above (1) to (10), wherein the resin composition as a whole has a weight average molecular weight of 100,000 or more and 200,000 or less.

[0028] (12) The present invention provides a resin composition according to any one of the above items (1) to (11), wherein the resin composition has a melt index of 3 g / 10 min or more and 13.5 g / 10 min or less, as measured at 190° C. under a load of 5 kg in accordance with ASTM D1238.

[0029] (13) In any one of the above (1) to (12), the resin composition has a tensile strength of 245 kgf / cm as measured in accordance with ASTM D638. 2 More than 500kgf / cm 2 The following resin composition is provided:

[0030] (14) The present invention provides a resin composition according to any one of the above (1) to (13), wherein the resin composition has an elongation of 400% or more as measured in accordance with ASTM D638.

[0031] (15) The present invention provides a resin composition according to any one of the above items (1) to (14), wherein the resin composition has an average domain diameter of 1 μm or less, based on the major axis of the domain observed on a test piece at a magnification of 25,000 times using a transmission electron microscope.

[0032] (16) The present invention provides a molded article obtained by molding the resin composition according to any one of (1) to (15) above. Effect of the Invention

[0033] The resin composition of the present invention is a biodegradable resin composition containing different types of biodegradable resins, and by applying a chemical compatibilizer to improve the compatibility between the different types of biodegradable resins, the compatibility is improved and the composition has excellent mechanical properties.

[0034] Furthermore, by adjusting the structure of the acrylic copolymer, which is a compatibilizer for different biodegradable resins, the resin composition of the present invention can suppress a rapid increase in viscosity and improve compatibility, even when the compatibilizer is used in the same content as the copolymer disclosed in Patent Document 1, and can be expanded to various formulations and applications.

[0035] Furthermore, molded articles made from the resin composition of the present invention have excellent mechanical properties and exhibit biodegradability. [Brief description of the drawings]

[0036] [Figure 1] 1 is an image of the surface of a test piece of the resin composition produced in Example 3 of the present invention, taken at a magnification of 25,000 times using a transmission electron microscope. [Diagram 2] 1 is an image of the surface of a test piece of the resin composition prepared in Comparative Example 1 of the present invention, taken at a magnification of 25,000 times using a transmission electron microscope. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] In the following, the present invention will be described in more detail in order to facilitate understanding of the present invention.

[0038] The terms and words used in the description of the present invention and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0039] In the present invention, the term "monomer unit" may refer to a component, structure, or substance itself derived from a monomer, and as a specific example, may refer to a repeating unit formed in a polymer by an input monomer participating in a polymerization reaction during polymerization of a polymer.

[0040] As used herein, the term "composition" is inclusive of mixtures of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0041] The present invention provides a resin composition.

[0042] The resin composition may be a biodegradable resin composition containing different kinds of biodegradable resins. As a specific example, the resin composition may include a first biodegradable resin, a second biodegradable resin, and at least one of an acrylic copolymer and a compatibilizing part formed from the acrylic copolymer, and the acrylic copolymer may include a methyl (meth)acrylate monomer unit, a (meth)acrylate monomer unit containing an epoxy group, and an alkyl (meth)acrylate monomer unit having 2 to 10 carbon atoms, and may include 15% by weight or more and 60% by weight or less of the (meth)acrylate monomer unit containing an epoxy group.

[0043] The first and second biodegradable resins are different from each other in type, and any resin known as a biodegradable resin can be used. As a specific example, the first biodegradable resin can be a polyester-based resin containing an aliphatic polyester unit and an aromatic polyester unit. As a more specific example, the first biodegradable resin can include polybutylene adipate terephthalate (PBAT). PBAT is a random copolymer of adipic acid, 1,4-butanediol, and terephthalic acid, and has been proposed as an alternative biodegradable resin to low-density polyethylene. In particular, the PBAT can ensure biodegradability from the aliphatic polyester unit formed from adipic acid and 1,4-butanediol, and mechanical properties from the aromatic polyester unit formed from terephthalic acid and 1,4-butanediol.

[0044] The second biodegradable resin may be any resin different from the first biodegradable resin, and as a specific example, the second biodegradable resin may include polylactic acid (PLA). PLA is an environmentally friendly biodegradable resin that is produced from biomaterials and naturally decomposes into water and carbon dioxide within a few months through the action of microorganisms.

[0045] The resin composition may contain the second biodegradable resin in an amount of 1 part by weight or more and 50 parts by weight or less, relative to 100 parts by weight of the first biodegradable resin. As a specific example, the resin composition may contain the second biodegradable resin in an amount of 1 part by weight or more, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more, relative to 100 parts by weight of the first biodegradable resin, and may contain the second biodegradable resin in an amount of 50 parts by weight or less, 49 parts by weight or less, 48 ​​parts by weight or less, 47 parts by weight or less, 46 parts by weight or less, 45 parts by weight or less, 44 parts by weight or less, or 43 parts by weight or less, and within this range, mechanical properties and processability may be further excellent.

[0046] The resin composition may contain at least one of the acrylic copolymer and the compatibilizing part formed from the acrylic copolymer in a content of 0.01 parts by weight or more and 10 parts by weight or less, relative to 100 parts by weight of the first biodegradable resin. As a specific example, the resin composition may contain at least one of the acrylic copolymer and the compatibilizing part formed from the acrylic copolymer in a content of 0.01 parts by weight or more, 0.05 parts by weight or more, 0.10 parts by weight or more, 0.11 parts by weight or more, 0.12 parts by weight or more, or 0.125 parts by weight or more, relative to 100 parts by weight of the first biodegradable resin, and may contain at most 10 parts by weight, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, 0.4 parts by weight or less, 0.3 parts by weight or less, or 0.2 parts by weight or less.

[0047] The acrylic copolymer is a copolymer containing a reactive functional group such as an epoxy group, and may be included as a chemical compatibilizer to improve the compatibility of different biodegradable resins in the resin composition. The acrylic copolymer may be present as itself in the resin composition, or may be present in the form of a compatibilizer formed by chemical bonding by reacting the reactive functional group with different biodegradable resins, or the two forms may coexist.

[0048] The acrylic copolymer may be an acrylic copolymer copolymerized with a methyl (meth)acrylate monomer, a (meth)acrylate monomer containing an epoxy group, and an alkyl (meth)acrylate monomer having 2 to 10 carbon atoms. As a specific example, the acrylic copolymer may be a random copolymer copolymerized with a methyl (meth)acrylate monomer, a (meth)acrylate monomer containing an epoxy group, and an alkyl (meth)acrylate monomer having 2 to 10 carbon atoms, and may be a linear random copolymer. Here, "(meth)acrylate" means both acrylate and methacrylate.

[0049] The acrylic copolymer may contain methyl (meth)acrylate monomer units formed from methyl (meth)acrylate monomers in a content of 25% by weight or more and 65% by weight or less. As a specific example, the acrylic copolymer may contain methyl (meth)acrylate monomer units formed from methyl (meth)acrylate monomers in a content of 25% by weight or more, 30% by weight or more, 35% by weight or more, or 40% by weight or more, or 65% by weight or less, 60% by weight or less, 55% by weight or less, or 50% by weight or less. Within this range, the copolymer has excellent compatibility with PLA and relatively excellent affinity with PBAT, and can further improve the compatibility between PBAT and PLA.

[0050] The acrylic copolymer may contain 15% by weight or more and 60% by weight or less of (meth)acrylate monomer units containing an epoxy group formed from a (meth)acrylate monomer containing an epoxy group. As a specific example, the acrylic copolymer may contain 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, or 40% by weight or more of (meth)acrylate monomer units containing an epoxy group formed from a (meth)acrylate monomer containing an epoxy group, and may contain 60% by weight or less, 55% by weight or less, 50% by weight or less, or 45% by weight or less of (meth)acrylate monomer units. Within this range, the flexibility of the polymer chain can be increased, the compatibility between different biodegradable resins can be further improved, and in particular, when a film is produced from the resin composition, the chain diffusion and entanglement between the film interfaces can be increased.

[0051] The (meth)acrylate monomer containing an epoxy group may be a (meth)acrylate monomer containing a glycidyl group, and a specific example of the (meth)acrylate monomer may be a glycidyl (meth)acrylate monomer. The (meth)acrylate monomer containing an epoxy group may function as a chemical compatibilizer by reacting the epoxy group contained in the monomer with a hydroxyl group (-OH) or a carboxylic acid group (-COOH) contained in PBAT or PLA. In addition, when the reaction occurs at the interface between PBAT and PLA, the compatibility and interfacial adhesion between PBAT and PLA may be further improved.

[0052] The acrylic copolymer may contain 5% by weight or more and 30% by weight or less of alkyl (meth)acrylate monomer units having 2 to 10 carbon atoms formed from alkyl (meth)acrylate monomers having 2 to 10 carbon atoms. As a specific example, the acrylic copolymer may contain 5% by weight or more, 10% by weight or more, or 15% by weight or more of alkyl (meth)acrylate monomer units having 2 to 10 carbon atoms formed from alkyl (meth)acrylate monomers having 2 to 10 carbon atoms, or may contain 30% by weight or less, 25% by weight or less, or 20% by weight or less of alkyl (meth)acrylate monomer units having 2 to 10 carbon atoms formed from alkyl (meth)acrylate monomers having 2 to 10 carbon atoms. Within this range, the flexibility of the polymer chain can be increased, the compatibility between different biodegradable resins can be further improved, and in particular, when a film is produced from the resin composition, the chain diffusion and entanglement at the film interface can be increased.

[0053] The alkyl (meth)acrylate monomer having 2 to 10 carbon atoms may be at least one selected from the group consisting of ethyl (meth)acrylate, n-propyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, iso-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, iso-decyl (meth)acrylate, dodecyl (meth)acrylate, iso-bornyl (meth)acrylate, and lauryl (meth)acrylate. As a specific example, the alkyl (meth)acrylate monomer having 2 to 10 carbon atoms may be an alkyl (meth)acrylate monomer having 3 to 9 or 4 to 8 carbon atoms, and as a more specific example, it may be one or more selected from the group consisting of butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.

[0054] The acrylic copolymer may be prepared by emulsion polymerization of a monomer mixture including the methyl (meth)acrylate monomer, the (meth)acrylate monomer containing an epoxy group, and the alkyl (meth)acrylate monomer having 2 to 10 carbon atoms, a polymerization initiator, an emulsifier, and the like.

[0055] The polymerization temperature and time during the polymerization of the acrylic copolymer may be adjusted as required. For example, the polymerization temperature may be within a range of 50° C. to 200° C., and the polymerization time may be within a range of 0.5 hours to 20 hours.

[0056] The polymerization initiator may be an inorganic or organic peroxide, and specific examples thereof include water-soluble polymerization initiators such as potassium persulfate, sodium persulfate, and ammonium persulfate, and oil-soluble polymerization initiators such as cumene hydroperoxide and benzoyl peroxide.

[0057] In order to promote the initiation of the reaction of the peroxide together with the polymerization initiator, an activator may be used together. As the activator, one or more selected from the group consisting of sodium formaldehyde sulfoxylate, sodium ethylenediaminetetraacetate, ferrous sulfate, and dextrose may be used.

[0058] The polymerization initiator may be added in an amount of 0.1 to 10 parts by weight, specifically 0.1 to 5 parts by weight, based on 100 parts by weight of the monomer mixture, on a dry weight basis.

[0059] The polymerization may be carried out by further including a chain transfer agent in order to increase the efficiency of the polymerization reaction. The chain transfer agent may play a role of introducing a homopolymer, which is a polymer composed of only one type of monomer, into a micelle during the polymerization process. The chain transfer agent may be a linear or branched alkylthiol compound having 5 to 20 carbon atoms, and specific examples thereof may include hexanethiol, cyclohexanethiol, adamantanethiol, heptanethiol, octanethiol, nonanethiol, decanethiol, undecanethiol, dodecanethiol, hexadecanethiol, and octadecanethiol. The chain transfer agent may be added in an amount of 0.1 to 10 parts by weight, and specific examples thereof may be 0.1 to 5 parts by weight, based on the dry weight, relative to 100 parts by weight of the monomer mixture.

[0060] The emulsion polymerization may be carried out including the following steps (S10) to (S30).

[0061] (S10) Step: A step of dispersing an emulsifier in a solvent to produce an emulsion (S20) Step: A step of preparing a pre-emulsion by mixing a monomer mixture containing each monomer component and an emulsifier, etc. (S30) step: A step of mixing the emulsion prepared in the (S10) step and the pre-emulsion prepared in the (S20) step in the presence of a polymerization initiator to carry out emulsion polymerization.

[0062] The emulsion polymerization for polymerizing the acrylic copolymer may be carried out through steps (S10) to (S30).

[0063] First, in step (S10), an emulsion containing an emulsifier is prepared. This is different from the process of preparing a pre-emulsion described below. The emulsifier may be an anionic emulsifier alone or may be an anionic emulsifier, a cationic emulsifier, and a non-ionic emulsifier together, and the emulsion may be prepared by mixing the emulsifier components and a solvent such as water. In the process of preparing the emulsion, micelle initial particles of several nanometers in size may be stably formed. In addition, in step (S20), a pre-emulsion containing the monomer mixture is prepared by mixing the above-mentioned monomers, emulsifier, etc. with water. In this case, the emulsifier may be an anionic emulsifier alone or may be an anionic emulsifier and the above-mentioned non-ionic emulsifier together. In this process, nano-sized latex particles may be formed in the pre-emulsion. That is, the emulsifier may be used in at least one of the steps of preparing the emulsion and the step of preparing the pre-emulsion. In addition, in step (S30), a polymerization initiator is added to the prepared emulsion, and then the pre-emulsion and the polymerization initiator are continuously added in equal ratios for a predetermined period of time.

[0064] The content of the polymerization initiator added to the emulsion may be more than 0 to 1 part by weight based on 100 parts by weight of the monomer mixture, and the content of the polymerization initiator added together with the pre-emulsion may be 0.1 to 2 parts by weight based on 100 parts by weight of the monomer mixture, and the continuous addition time may be about 3 to 7 hours. Through this process, the floating monomer or polymer in the pre-emulsion may flow into the initial particles generated in the emulsion. The result of this reaction may then be subjected to a thermal polymerization process in the presence of an additional polymerization initiator, whereby the remaining monomer is polymerized. Here, the polymerization initiator may be further added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the monomer mixture, and the thermal polymerization may be performed at a temperature of about 75°C to about 85°C for about 40 to about 80 minutes. Such an emulsion polymerization method is divided into a process for preparing an emulsion and a process for preparing a pre-emulsion, and can be carried out by a simple method of subsequently mixing the pre-emulsion with the emulsion, thereby improving process stability and productivity compared to conventional methods.

[0065] The emulsifier used in the emulsion polymerization may include at least one selected from the group consisting of anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers. The emulsifier is a material having both a hydrophilic group and a hydrophobic group, and forms a micelle structure during the emulsion polymerization, allowing the polymerization of each monomer to occur inside the micelle structure. Emulsifiers commonly used in emulsion polymerization are classified into anionic emulsifiers, cationic emulsifiers, and nonionic emulsifiers, and two or more of them may be mixed together to improve polymerization stability during emulsion polymerization. As a specific example, the nonionic emulsifier may include at least one selected from the group consisting of polyethylene oxide alkyl aryl ethers, polyethylene oxide alkyl amines, and polyethylene oxide alkyl esters. The anionic emulsifier may include one or more selected from the group consisting of sodium alkyl diphenyl ether disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene aryl ether sulfate, sodium alkyl sulfate, sodium alkyl benzene sulfonate, and dialkyl sodium sulfosuccinate. These may be used alone or in combination of two or more, and may be more effective when an anionic emulsifier and a nonionic emulsifier are used in combination. The emulsifier may be used in an amount of about 0.1 parts by weight to about 10 parts by weight, or about 1 part by weight to about 5 parts by weight, based on 100 parts by weight of the total monomer components used in the production of the latex particles.

[0066] The polymerization composition may further include an aqueous solvent such as water in addition to the emulsifier or monomer component. Here, the aqueous solvent may be used in an amount of about 10 to about 1,000 parts by weight based on 100 parts by weight of the latex particles in terms of adjusting the stability and viscosity of the latex particles, and may be used so that the total solid content (TSC) is adjusted to about 10% by weight to about 60% by weight based on the total amount of the composition.

[0067] The acrylic copolymer may have an epoxy equivalent weight (EEW) of 200 g / eq or more and 800 g / eq or less. As a specific example, the acrylic copolymer may have an epoxy equivalent weight (EEW) of 200 g / eq or more, 210 g / eq or more, 220 g / eq or more, 230 g / eq or more, 240 g / eq or more, 250 g / eq or more, 260 g / eq or more, 270 g / eq or more, 280 g / eq or more, 290 g / eq or more, 300 g / eq or more, 310 g / eq or more, 320 g / eq or more, 330 g / eq or more, 340 g / eq or more, or 350 g / eq or more, and may have an epoxy equivalent weight (EEW) of 800 g / eq or less, 700 g / eq or less, 700 g / eq or less, 700 g / eq or less, 700 g / eq or less, 700 g / eq or less, 700 g / eq or less, 700 g / eq or less, 700 g / eq or less, 700 g / eq or more ... 00g / eq or less, 600g / eq or less, 500g / eq or less, 490g / eq or less, 480g / eq or less, 470g / eq or less, 460g / eq or less, 450g / eq or less, 440g / eq or less, 430g / eq or less, 420g / eq or less, 410g / eq or less, 400g / eq or less, 390g / eq or less, 380g / eq or less, 370g / eq or less, or 360g / eq or less, and within this range, the compatibility between different biodegradable resins can be further improved. In particular, when the biodegradable resin is a polyester resin, it can effectively react with the hydroxyl group or carboxylic acid group of the polyester resin, and further improve its performance as a chemical compatibilizer.

[0068] The acrylic copolymer may have a weight average molecular weight of 10,000 or more and 100,000 or less. As a specific example, the acrylic copolymer may have a weight average molecular weight of 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, or 30,000 or more, or 100,000 or less, 90,000 or less, 80,000 or less, 70,000 or less, 60,000 or less, 50,000 or less, or 40,000 or less. Within this range, the inherent properties of different biodegradable resins, particularly polyester resins, are not impaired, and the function as a chemical compatibilizer may be more excellent. The weight average molecular weight may be expressed without a unit, but may be expressed in units of g / mol depending on the molar mass.

[0069] The acrylic copolymer may have a glass transition temperature of 45° C. or more and 85° C. or less. As a specific example, the acrylic copolymer may have a glass transition temperature of 45° C. or more, 46° C. or more, 47° C. or more, 48° C. or more, 49° C. or more, 50° C. or more, 51° C. or more, 52° C. or more, 53° C. or more, 54° C. or more, 55° C. or more, 56° C. or more, 57° C. or more, 58° C. or more, or 59° C. or more, and may have a glass transition temperature of 85° C. or less, 84° C. or less, 83° C. or less, 82° C. or less, 81° C. or less, 80° C. or less, 79° C. or less, 78° C. or less, 77° C. or less, 76° C. or less, 75° C. or less, 74° C. or less, 73° C. or less, 72° C. or less, 71° C. or less, or 70° C. or less, and within this range, it may be easier to process into a compatibilizer for a resin composition containing a different type of biodegradable resin.

[0070] The resin composition may have a weight average molecular weight of 100,000 or more and 200,000 or less. As a specific example, the resin composition may have a weight average molecular weight of 100,000 or more, 105,000 or more, 110,000 or more, 115,000 or more, 120,000 or more, 125,000 or more, or 130,000 or more, and may have a weight average molecular weight of 200,000 or less, 195,000 or less, 190,000 or less, 185,000 or less, 180,000 or less, 175,000 or less, 170,000 or less, 165,000 or less, 160,000 or less, or 155,000 or less, and within this range, the tensile properties of the resin composition can be further improved.

[0071] The resin composition may have a melt index measured in accordance with ASTM D1238 at 190° C. under a load of 5 kg of 3 g / 10 min or more and 13.5 g / 10 min or less. As a specific example, the resin composition may have a melt index, measured at 190° C. under a load of 5 kg in accordance with ASTM D1238, of 3 g / 10 min or more, 4 g / 10 min or more, 5 g / 10 min or more, 6 g / 10 min or more, or 6.5 g / 10 min or more, and may be 13.5 g / 10 min or less, 13 g / 10 min or less, 12.5 g / 10 min or less, 12 g / 10 min or less, 11.5 g / 10 min or less, 11 g / 10 min or less, 10.5 g / 10 min or less, 10 g / 10 min or less, 9.5 g / 10 min or less, or 9 g / 10 min or less. Within this range, the resin composition has excellent tensile strength and maintains a proper level of viscosity, thereby further improving processability.

[0072] The resin composition has a tensile strength of 245 kgf / cm as measured according to ASTM D638. 2 More than 500kgf / cm 2 As a specific example, the resin composition may have a tensile strength of 245 kgf / cm or less as measured in accordance with ASTM D638. 2 Above, 250kgf / cm 2 Above, 260kgf / cm 2 Above, 270kgf / cm 2 Above, 280kgf / cm 2 or more, or 290kgf / cm 2 It can be more than 500kgf / cm 2 Below, 490kgf / cm 2 Below, 480kgf / cm 2 Below, 470kgf / cm 2 Below, 460kgf / cm 2 Below, 450kgf / cm 2 Below, 440kgf / cm 2 Below, 430kgf / cm 2 Below, 420kgf / cm 2 Below, 410kgf / cm 2 Below 400kgf / cm2 Below, 390kgf / cm 2 or less than 380kgf / cm 2 It can be the following:

[0073] The resin composition may have an elongation of 400% or more as measured in accordance with ASTM D638. As a specific example, the resin composition may have an elongation of 400% or more, 410% or more, 420% or more, 430% or more, 440% or more, 450% or more, 460% or more, 470% or more, 480% or more, 490% or more, 500% or more, 510% or more, 520% ​​or more, 530% or more, 540% or more, 550% or more, 560% or more, 570% or more, 580% or more, 590% or more, or 600% or more as measured in accordance with ASTM D638, and may be 700% or less, 690% or less, 680% or less, 670% or less, 660% or less, or 650% or less.

[0074] The resin composition may have an average domain diameter of 1 μm or less, based on the major axis of the domain observed when a test piece is magnified at 25,000 times using a transmission electron microscope. As a specific example, the resin composition may have an average domain diameter of 1 μm or less, 0.9 μm or less, 0.8 μm or less, 0.7 μm or less, 0.6 μm or less, or 0.5 μm or less, based on the major axis of the domain observed when a test piece is magnified at 25,000 times using a transmission electron microscope, and may also have an average domain diameter of 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, or 0.2 μm or more.

[0075] The present invention provides a molded article.

[0076] The molded article may be a biodegradable molded article molded from the resin composition, i.e., a biodegradable resin composition. Here, the molded article includes not only an injection molded article formed by injection or the like, but also a film molded article formed by film formation.

[0077] The molded article may be a biodegradable film, and specific examples thereof include an agricultural mulching film and a film for use as a food packaging material.

[0078] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to exemplary embodiments thereof, so that those skilled in the art can easily practice the present invention. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0079] (Production Example and Comparative Production Example: Production of Acrylic Copolymer) (Production Example 1) In a 3L glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, 200 parts by weight of distilled water and 0.5 parts by weight of sodium dioctyl sulfosuccinate (sodium bis(2-ethylhexyl) sulfosuccinate) as an emulsifier were added to a total of 100 parts by weight of monomers methyl methacrylate, glycidyl methacrylate, butyl acrylate and 2-ethylhexyl acrylate, and the mixture was stirred. After the inside of the reactor was replaced with nitrogen gas while stirring, the glass reactor was heated to 70°C, 0.2 parts by weight of potassium persulfate was added, and the mixture was maintained for 30 minutes.

[0080] Separately, 45 parts by weight of methyl methacrylate, 40 parts by weight of glycidyl methacrylate, and 15 parts by weight of butyl acrylate were added to a beaker and thoroughly mixed for 30 minutes, and 0.5 parts by weight of 1-octanethiol was added as a chain transfer agent relative to the total of 100 parts by weight of the monomers, and after thoroughly mixing with a stirrer, the mixture was continuously added to the glass reactor at equal intervals for 4 hours.

[0081] After 4 hours of polymerization reaction, the temperature inside the glass reactor was maintained at 70°C for 30 minutes and then cooled to room temperature. The emulsion polymerization product was coagulated using an aqueous calcium acetate solution, heated to 85°C, dehydrated, and dried at 60°C for 16 hours to obtain an acrylic copolymer.

[0082] (Production Example 2) An acrylic copolymer was obtained in the same manner as in Preparation Example 1, except that 15 parts by weight of 2-ethylhexyl acrylate was used instead of 15 parts by weight of butyl acrylate.

[0083] (Production Example 3) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 55 parts by weight of methyl methacrylate was added instead of 45 parts by weight, and 30 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight.

[0084] (Production Example 4) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 30 parts by weight of methyl methacrylate was added instead of 45 parts by weight, and 55 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight.

[0085] (Production Example 5) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 30 parts by weight of methyl methacrylate was added instead of 45 parts by weight, 55 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight, and 15 parts by weight of 2-ethylhexyl acrylate was added instead of 15 parts by weight of butyl acrylate.

[0086] (Production Example 6) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 55 parts by weight of methyl methacrylate was added instead of 45 parts by weight, 20 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight, and 25 parts by weight of 2-ethylhexyl acrylate was added instead of 15 parts by weight of butyl acrylate.

[0087] (Comparative Manufacturing Example 1) A commercially available copolymer (a copolymer of methyl methacrylate, butyl acrylate, glycidyl methacrylate and styrene) used in the production of Masterbatch A described in Patent Document 1 was used.

[0088] (Comparative Manufacturing Example 2) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 64 parts by weight of methyl methacrylate was added instead of 45 parts by weight, 2.1 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight, and 33.9 parts by weight of butyl acrylate was added instead of 15 parts by weight.

[0089] (Comparative Manufacturing Example 3) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 62.3 parts by weight of methyl methacrylate was added instead of 45 parts by weight, 5.2 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight, and 32.5 parts by weight of 2-ethylhexyl acrylate was added instead of 15 parts by weight of butyl acrylate.

[0090] (Comparative Manufacturing Example 4) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 60 parts by weight of methyl methacrylate was added instead of 45 parts by weight, 10 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight, and 30 parts by weight of butyl acrylate was added instead of 15 parts by weight.

[0091] (Comparative Manufacturing Example 5) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 10 parts by weight of methyl methacrylate was added instead of 45 parts by weight, 64.8 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight, and 25.2 parts by weight of butyl acrylate was added instead of 15 parts by weight.

[0092] (Comparative Manufacturing Example 6) An acrylic copolymer was obtained by carrying out the same procedure as in Preparation Example 1, except that 10 parts by weight of methyl methacrylate was added instead of 45 parts by weight, 75 parts by weight of glycidyl methacrylate was added instead of 40 parts by weight, and 15 parts by weight of 2-ethylhexyl acrylate was added instead of 15 parts by weight of butyl acrylate.

[0093] (Comparative Manufacturing Example 7) <Production of acrylic core latex> A 3 L glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser was charged with 100 parts by weight of the monomers methyl methacrylate, glycidyl methacrylate, and butyl acrylate to be added in the production of the core and shell, 80 parts by weight of distilled water, sodium bicarbonate (NaHCO 3 0.2 parts by weight of ferrous sulfate, 0.001 parts by weight of ferrous sulfate, and 0.18 parts by weight of disodium ethylenediaminetetraacetate were added and stirred. During stirring, the inside of the reactor was replaced with nitrogen gas, and the inside temperature of the glass reactor was raised to 50°C and maintained at that temperature.

[0094] Separately, in order to prepare a monomer pre-emulsion, 50 parts by weight of distilled water, 0.6 parts by weight of sodium lauryl sulfonate, and 85 parts by weight of butyl acrylate were added to prepare a monomer pre-emulsion.

[0095] The monomer pre-emulsion was continuously added for 5 hours while the internal temperature of the reactor was maintained at 50° C., and 0.2 parts by weight of t-butyl hydroperoxide and 0.2 parts by weight of sodium formaldehyde sulfoxylate were added simultaneously as initiators to initiate the reaction. 30 minutes after the addition of the monomer pre-emulsion was completed, 0.01 parts by weight of t-butyl hydroperoxide and 0.02 parts by weight of sodium formaldehyde sulfoxylate were further added, and the mixture was aged for 1 hour to produce an acrylic core latex containing an acrylic core polymer. Here, the polymerization conversion rate was 99%, and the total solid content was 40% by weight.

[0096] <Production of graft copolymer latex> While maintaining the reactor temperature at 70° C., 10 parts by weight of distilled water and 0.1 parts by weight of sodium lauryl sulfonate were added to the reactor with stirring, based on a total of 100 parts by weight of methyl methacrylate, glycidyl methacrylate and butyl acrylate, which are monomers added during the production of the core and shell. During stirring, the inside of the reactor was replaced with nitrogen gas.

[0097] Separately, 13 parts by weight of methyl methacrylate, 2 parts by weight of glycidyl methacrylate, and 0.2 parts by weight of 1-octanediol as a chain transfer agent were placed in a beaker and thoroughly stirred with a stirrer to prepare a graft monomer mixture.

[0098] The graft monomer mixture prepared above was continuously added to the reactor for 1 hour to carry out graft polymerization to prepare a graft copolymer latex containing a core-shell graft copolymer, where the polymerization conversion rate was 99% and the total solid content was 42 wt%.

[0099] (Comparative Manufacturing Example 8) In Comparative Preparation Example 7, 80 parts by weight of 2-ethylhexyl acrylate was added instead of 85 parts by weight of butyl acrylate when preparing the acrylic core latex, and 18 parts by weight of methyl methacrylate was added instead of 13 parts by weight when preparing the graft copolymer latex. The same procedure as in Comparative Preparation Example 7 was carried out to obtain a core-shell graft copolymer.

[0100] (Comparative Manufacturing Example 9) In Comparative Preparation Example 7, 80 parts by weight of butyl acrylate was added instead of 85 parts by weight in the preparation of the acrylic core latex, 15 parts by weight of methyl methacrylate was added instead of 13 parts by weight in the preparation of the graft copolymer latex, and 5 parts by weight of glycidyl methacrylate was added instead of 2 parts by weight in the preparation of the graft copolymer latex. The same procedure as in Comparative Preparation Example 7 was carried out to obtain a core-shell graft copolymer.

[0101] (Comparative Manufacturing Example 10) In Comparative Preparation Example 7, 80 parts by weight of 2-ethylhexyl acrylate was used instead of 85 parts by weight of butyl acrylate when preparing the acrylic core latex, and 15 parts by weight of methyl methacrylate was used instead of 13 parts by weight when preparing the graft copolymer latex, and 5 parts by weight of glycidyl methacrylate was used instead of 2 parts by weight when preparing the graft copolymer latex. The same procedure as in Comparative Preparation Example 7 was carried out to obtain a core-shell graft copolymer.

[0102] (Examples and Comparative Examples: Production of Resin Compositions) Example 1 Polybutylene adipate terephthalate (manufacturer: Xinjiang Blueridge Tunhe Chemical Industry Co., Ltd., product name: TH801T) and polylactic acid (manufacturer: Natureworks, product name: Ingeo Biopolymer 2003D) were each dried in an oven at 60° C. for 24 hours.

[0103] Next, 80 parts by weight of polybutylene adipate terephthalate, 20 parts by weight of polylactic acid, and 0.1 parts by weight of the acrylic copolymer obtained in Production Example 1 were mixed and blended for 8 minutes at 180°C and 60 rpm using a Haake Rheomix OS Lab mixer manufactured by Thermo Electron Karlsruhe GmbH. The mixture was then pulverized to obtain a resin composition.

[0104] Example 2 A resin composition was obtained in the same manner as in Example 1, except that 0.3 parts by weight of the acrylic copolymer obtained in Preparation Example 1 was added instead of 0.1 parts by weight.

[0105] Example 3 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Preparation Example 1 was added instead of 0.1 part by weight.

[0106] Example 4 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Preparation Example 2 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0107] Example 5 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Preparation Example 3 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0108] Example 6 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Preparation Example 4 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0109] Example 7 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Preparation Example 5 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0110] Example 8 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Preparation Example 6 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0111] Comparative Example 1 A resin composition was obtained in the same manner as in Example 1, except that the acrylic copolymer obtained in Preparation Example 1 was not added.

[0112] Comparative Example 2 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the copolymer of Comparative Preparation Example 1 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0113] Comparative Example 3 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 2 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0114] Comparative Example 4 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 3 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0115] Comparative Example 5 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 4 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0116] Comparative Example 6 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 5 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0117] Comparative Example 7 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 6 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0118] Comparative Example 8 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 7 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0119] Comparative Example 9 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 8 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0120] Comparative Example 10 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 9 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0121] Comparative Example 11 A resin composition was obtained in the same manner as in Example 1, except that 1 part by weight of the acrylic copolymer obtained in Comparative Preparation Example 10 was added instead of 0.1 part by weight of the acrylic copolymer obtained in Preparation Example 1.

[0122] (Experimental Example) (Experimental Example 1) The glass transition temperature, molecular weight and epoxy equivalent of the acrylic copolymers produced in Production Examples 1 to 6 and Comparative Production Examples 2 to 10 were measured by the following methods, and the results are shown in Table 1 below together with the copolymer structure and monomer composition.

[0123] Furthermore, the glass transition temperature, molecular weight and epoxy equivalent of the copolymer of Comparative Production Example 1 were measured and are shown in Table 1 below.

[0124] *Glass transition temperature (℃): Using a differential scanning calorimeter (manufacturer: TA Instruments, model name: DSC 250), 8 mg (error range 1 mg) of each acrylic copolymer sample manufactured in the above Manufacturing Example and Comparative Manufacturing Example was put in, and the sample was primarily heated to 300℃ at a heating rate of 10℃ / min under a nitrogen flow, cooled to 0℃ at a heating rate of 10℃ / min, and then secondary heated to 300℃ at a heating rate of 10℃ / min to measure the glass transition temperature.

[0125] *Weight average molecular weight and number average molecular weight: The weight average molecular weight and number average molecular weight of the obtained acrylic copolymer sample were measured under the following conditions using gel permeation chromatography (GPC, PL GPC220, manufactured by Agilent Technologies). Here, the sample was prepared by dissolving the sample in tetrahydrofuran (stabilized with BHT) as a solvent at a concentration of 2 mg / ml and taking a part of the solution.

[0126] -Column: PL MiniMixed BX 2 -Solvent: Tetrahydrofuran (Stabilized with BHT) -Flow rate: 0.3ml / min -Sample concentration: 2.0mg / ml -Column temperature: 40℃ -Detector: Waters 2414 Refractive Index Detector -Data processing: Empower - Calibration curve: Polystyrene standards (molecular weight: 9 types: 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000 / 10,000,000)

[0127] *Epoxy equivalent (g / eq): Using a 700 MHz NMR spectrometer manufactured by Bruker, the content ratio (molar ratio) of glycidyl methacrylate was measured according to nuclear magnetic resonance spectroscopy, from which the number of equivalents of epoxy groups (eq / mol) was obtained, and the epoxy equivalent (g / eq) was calculated using the number average molecular weight (Mn) value measured above.

[0128] [Table 1]

[0129] (Experimental Example 2) The resin compositions prepared in Example 1 and Comparative Example 1 were placed in a mold measuring 130 mm x 130 mm x 2 mm, preheated at 180°C for about 5 minutes, pressed under a compressive load of 20 MPa for 3 minutes, and quenched at room temperature to prepare test specimens. The cross sections of the test specimens were then microtomed and magnified at 25,000 times using a transmission electron microscope, and are shown in Figure 1 (Example 3) and Figure 2 (Comparative Example 1), respectively.

[0130] As shown in FIG. 1, in the case of Example 3, domains of polylactic acid (light areas) are present within the polybutylene adipate terephthalate (dark areas). Even in the case of the largest domain, the size of the domain based on the major axis is less than about 0.5 μm, and it was clearly confirmed that the polylactic acid domains were formed very small.

[0131] On the other hand, as shown in FIG. 2, in the case of Comparative Example 1 in which no separate compatibilizer was added, domains of polylactic acid (light areas) were present within polybutylene adipate terephthalate (dark areas), and the domain sizes based on the major axis of the domains ranged from as small as about 0.5 μm to as large as about 1.5 μm, confirming that large domains of polylactic acid were formed.

[0132] For Figures 1 and 2, the average diameter based on the long axis of the domain was analyzed using the Anlyze tool of ImageJ software. As a result, in the case of Example 3, the average diameter of the polylactic acid domain based on the long axis of the domain was confirmed to be approximately 0.3 μm, and in the case of Comparative Example 1, the average diameter of the polylactic acid domain based on the long axis of the domain was confirmed to be approximately 1.2 μm.

[0133] From these results, it was confirmed that in the resin composition produced in the examples of the present invention, the compatibility between polylactic acid and polybutylene adipate terephthalate is improved by the acrylic copolymer, and polylactic acid is small and uniformly dispersed.

[0134] (Experimental Example 3) For the resin compositions produced in Examples 1 to 8 and Comparative Examples 1 to 11, the molecular weight, molecular weight distribution, tensile strength, elongation and melt index were measured by the following methods, and the results are shown in Table 2 below.

[0135] *Weight average molecular weight, number average molecular weight, molecular weight distribution, and molecular weight increase rate: The weight average molecular weight and number average molecular weight of the obtained resin composition sample were measured under the following conditions using gel permeation chromatography (GPC, PL GPC220, manufactured by Agilent Technologies). Here, the sample was a part of a solution dissolved in chloroform as a solvent at a concentration of 1 mg / ml.

[0136] -Column: PL MiniMixed BX 2 -Solvent: Chloroform -Flow rate: 1.0mL / min -Sample concentration: 1.0mg / ml -Column temperature: 40℃ -Detector: Waters 2414 Refractive Index Detector -Data processing: Empower - Calibration curve: Polystyrene standards (molecular weight: 9 types: 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000 / 10,000,000)

[0137] In addition, based on the weight average molecular weight measured for the resin composition of Comparative Example 1 not containing an acrylic copolymer, the increase rates of the weight average molecular weight measured for the resin compositions of Examples 1 to 8 and Comparative Examples 2 to 11 were calculated according to the following Equation 1.

[0138] [Mathematical formula 1] Molecular weight increase rate=(weight average molecular weight measured for the resin compositions of Examples 1 to 8 and Comparative Examples 2 to 11 / weight average molecular weight measured for the resin composition of Comparative Example 1)×100

[0139] *Tensile strength and elongation: The obtained resin compositions were placed in molds measuring 130 mm x 130 mm x 2 mm, preheated at 180°C for about 5 minutes, pressed under a compressive load of 20 MPa for 3 minutes, and quenched at room temperature to prepare test specimens. The prepared test specimens were prepared as test specimens in accordance with the ASTM D638, Type 4 standard, and the elongation and tensile strength were measured using an Instron universal physical property testing machine (Instron 3365) at 50 mm / min in accordance with the ASTM D638 standard.

[0140] *Melt index (g / 10 min): The melt index of the obtained resin composition sample was measured using MI-4 manufactured by Gottfert in accordance with ASTM D1238 (190° C., 5 kg).

[0141] [Table 2]

[0142] As shown in Table 2, the resin composition of Comparative Example 2 containing the copolymer disclosed in Patent Document 1 as a compatibilizer had a significantly increased weight average molecular weight and increased tensile strength compared to the resin composition of Comparative Example 1 not containing a compatibilizer. However, it was confirmed that the viscosity increased rapidly, the melt index was so low that it could not be measured, and the elongation was rather decreased.

[0143] Meanwhile, it was confirmed that the resin compositions prepared in Examples 1 to 8 of the present invention, which contain the acrylic copolymer defined in the present invention as a compatibilizer, had increased tensile strength while maintaining the same or higher elongation rate compared to the resin composition prepared in Comparative Example 1 which did not contain a compatibilizer. In particular, it was confirmed that the resin compositions had a higher melt index and better processability compared to the resin composition of Comparative Example 2 which contains the same content of compatibilizer.

[0144] On the other hand, the resin compositions prepared in Comparative Examples 3 to 5, which have a low content of epoxy group-containing (meth)acrylate monomer units prepared in Comparative Preparation Examples 2 to 4 and use an acrylic copolymer containing methyl (meth)acrylate monomer units and an excessive amount of alkyl (meth)acrylate monomer units having 2 to 10 carbon atoms as a compatibilizer, showed very little change in processability and tensile properties due to melt index, despite the addition of a compatibilizer.

[0145] In addition, the resin compositions prepared in Comparative Examples 6 and 7, which had a high content of epoxy group-containing (meth)acrylate monomer units prepared in Comparative Preparation Examples 5 and 6 and used an acrylic copolymer containing a trace amount of methyl (meth)acrylate monomer units as a compatibilizer, showed a significant decrease in elongation due to a rapid increase in the epoxy equivalent in the acrylic copolymer caused by an increase in the content of epoxy group-containing (meth)acrylate monomer units, and an excessive increase in the interfacial adhesion strength between PLA and PBAT.

[0146] In addition, it was confirmed that the resin compositions prepared in Comparative Examples 8 to 11, in which the core-shell acrylic copolymers prepared in Comparative Preparation Examples 7 to 10 were used as compatibilizers, inhibited the compatibility between PLA and PBAT, resulting in reduced tensile properties.

[0147] From these results, it was confirmed that the resin composition of the present invention has improved compatibility by applying a chemical compatibilizer to improve the compatibility between different biodegradable resins, and has excellent mechanical properties.

Claims

1. The composition includes at least one of a first biodegradable resin, a second biodegradable resin, an acrylic copolymer, and a compatibilizing part formed from the acrylic copolymer; The acrylic copolymer contains methyl (meth)acrylate monomer units, (meth)acrylate monomer units containing an epoxy group, and alkyl (meth)acrylate monomer units having 2 to 10 carbon atoms, and contains 15% by weight or more and 60% by weight or less of the (meth)acrylate monomer units containing an epoxy group.

2. The resin composition according to claim 1 , wherein the first biodegradable resin comprises an aliphatic polyester unit and an aromatic polyester unit.

3. The resin composition of claim 1 , wherein the first biodegradable resin comprises polybutylene adipate terephthalate.

4. The resin composition according to claim 1 , wherein the second biodegradable resin comprises polylactic acid.

5. The resin composition according to claim 1 , wherein the resin composition contains the second biodegradable resin in a content of 1 part by weight or more and 50 parts by weight or less per 100 parts by weight of the first biodegradable resin.

6. The resin composition according to claim 1, wherein the resin composition contains at least one of the acrylic copolymer and the compatibilizing part formed from the acrylic copolymer in an amount of 0.01 parts by weight or more and 10 parts by weight or less per 100 parts by weight of the first biodegradable resin.

7. The resin composition according to claim 1, wherein the acrylic copolymer contains 25% by weight or more and 65% by weight or less of methyl (meth)acrylate monomer units, 15% by weight or more and 60% by weight or less of (meth)acrylate monomer units containing an epoxy group, and 5% by weight or more and 30% by weight or less of alkyl (meth)acrylate monomer units having 2 to 10 carbon atoms.

8. The resin composition according to claim 1, wherein the acrylic copolymer has an epoxy equivalent (E.E.W.) of 200 g / eq or more and 800 g / eq or less.

9. The resin composition according to claim 1 , wherein the acrylic copolymer has a weight average molecular weight of 10,000 or more and 100,000 or less.

10. The resin composition according to claim 1 , wherein the acrylic copolymer has a glass transition temperature of 45° C. or more and 85° C. or less.

11. The resin composition according to claim 1, wherein the weight average molecular weight of the entire resin composition is 100,000 or more and 200,000 or less.

12. The resin composition according to claim 1, wherein the resin composition has a melt index of 3 g / 10 min or more and 13.5 g / 10 min or less, measured at 190° C. under a load of 5 kg in accordance with ASTM D1238.

13. The resin composition has a tensile strength of 245 kgf / cm as measured according to ASTM D638. 2 More than 500kgf / cm 2 The resin composition according to claim 1, wherein:

14. The resin composition according to claim 1, wherein the resin composition has an elongation of 400% or more as measured in accordance with ASTM D638.

15. 2. The resin composition according to claim 1, wherein a test piece of the resin composition has an average domain diameter of 1 μm or less, based on the major axis of the domain observed when magnified at 25,000 times using a transmission electron microscope.

16. A molded article molded from the resin composition according to any one of claims 1 to 15.

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