Thermoplastic resin composition, method for producing thermoplastic resin composition, and use of plastic film

Abstract

The present invention provides a thermoplastic resin composition, a method for preparing the same, and a use thereof. The thermoplastic resin composition includes poly (butylene adipate / terephthalate), polylactic acid, and an additive. And the additive is selected from one of a group consisting of a phenolic antioxidant, a styrene-maleic anhydride copolymer and the phenolic antioxidant. The weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer is less than 10000. The content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3000 ppm.

Description

Technical Field

[0001] The present invention relates to polymer materials, and in particular to a thermoplastic resin composition, a preparation method of the thermoplastic resin composition and a use of a plastic film. Background Art

[0002] Polylactic acid (PLA) is a relatively mature biodegradable resin and an ideal material to replace petroleum-based resins such as polyethylene. Although PLA, which is used to replace polyethylene in the production of cling film, packaging film and agricultural film, has high tensile strength, poor tear resistance, slow crystallization rate, low crystallinity and low heat deformation temperature, it is difficult to meet the technical requirements of polyethylene film; polybutylene adipate terephthalate (PBAT) has good flexibility and film-forming properties, high thermal stability, and is suitable for the manufacture of film products, but its strength and modulus are low, and its price is high, so its promotion and application are also limited. To this end, in an attempt to achieve matching performance, the two are blended to prepare PBAT / PLA materials.

[0003] Adding polylactic acid to polybutylene adipate terephthalate can improve the elongation of PBAT / PLA materials to a certain extent, but it will reduce the tensile strength and tear resistance. For example, how to simultaneously maintain the tensile strength in the width direction (TD direction) of the film and the tear resistance in the length direction (MD direction) of the film is a problem that needs to be solved.

[0004] Therefore, the market needs improved PBAT / PLA thermoplastic resin compositions having enhanced physical properties. Summary of the invention

[0005] According to one embodiment of the present invention, a thermoplastic resin composition is provided. The thermoplastic resin composition comprises polybutylene adipate terephthalate, polylactic acid, and an additive. The additive is selected from one of the group consisting of a phenolic antioxidant, and a styrene maleic anhydride copolymer (styrene maleic anhydride; SMA) and a phenolic antioxidant. The weight-average molecular weight (weight-average molecular weight; Mw) of the styrene maleic anhydride copolymer is less than 10000. The content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3000 ppm.

[0006] According to another embodiment of the present invention, a method for preparing a thermoplastic resin composition is provided. The method comprises passing polybutylene adipate terephthalate, polylactic acid, and an additive through a molding device to obtain a thermoplastic resin composition. The additive is selected from one of the groups consisting of a phenolic antioxidant and a styrene-maleic anhydride copolymer and a phenolic antioxidant. The weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer is less than 10,000. The content of the phenolic antioxidant in the thermoplastic resin composition is greater than or equal to 1 ppm and less than 3,000 ppm.

[0007] According to another embodiment of the present invention, there is provided a use of a plastic film, wherein the plastic film is composed of a thermoplastic resin composition, and the plastic film is used for at least one of a plastic bag, a shopping bag, and an agricultural film.

[0008] The present invention provides a thermoplastic resin composition comprising polybutylene adipate terephthalate, polylactic acid and an additive, a method for preparing the thermoplastic resin composition, and the use of a plastic film composed of the thermoplastic resin composition. The thermoplastic resin composition and the plastic film provided by the present invention have the characteristics of improved tensile strength, tear strength, crystallinity and thermal stability due to their components.

[0009] In order to better understand the above and other aspects of the present invention, the following embodiments are described in detail as follows: DETAILED DESCRIPTION

[0010] The present invention provides a thermoplastic resin composition. The thermoplastic resin composition comprises polybutylene adipate terephthalate, polylactic acid, and an additive. The additive is selected from the group consisting of a phenolic antioxidant and a styrene-maleic anhydride copolymer and a phenolic antioxidant.

[0011] Hereinafter, each component in the thermoplastic resin composition will be described in detail.

[0012] <Polybutylene adipate terephthalate>

[0013] Polybutylene adipate terephthalate (PBAT) is a copolymer of butylene adipate (BA) and butylene terephthalate (BT). It has the characteristics of both PBA (polybutylene adipate) and PBT (polybutylene terephthalate). It has good mechanical properties and excellent biodegradability. It is a fully biodegradable material and is widely used in agriculture, packaging, medical and other fields.

[0014] The polybutylene adipate terephthalate (PBAT) described in the present invention can be synthesized by a common method in the art. For example, it is prepared by reacting a mixture consisting of the following components, essentially consisting of (a1) 35 to 95 mol %, preferably 45 to 80 mol % of adipic acid or its ester-forming derivatives (especially di-C1-C6-alkyl esters, such as dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate, dibutyl terephthalate, dipentyl terephthalate and dihexyl terephthalate or mixtures thereof, preferably adipic acid and dimethyl adipate or mixtures thereof), 5 to 65 mol %, preferably 20 to 55 mol % of terephthalic acid or its ester-forming derivatives (especially di-C1-C6-alkyl esters, such as dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate, dibutyl terephthalate, dipentyl terephthalate or mixtures thereof, preferably terephthalic acid and dimethyl terephthalate or mixtures thereof), the sum of the molar percentages being 100% and (a2) a dihydroxy compound selected from C2-C6-alkanediol and C5-C10-cycloalkanediol. The molar ratio of component (a1) to component (a2) is 0.4:1 to 1.5:1, preferably 0.6:1 to 1.1:1.

[0015] The dihydroxy compound (a2) used above is selected from C2-C6-alkanediols and C5-C10-cycloalkanediols, such as ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2- and 1,4-butanediol, 1,5-pentanediol or 1,6-hexanediol, in particular ethylene glycol, 1,3-propylene glycol and 1,4-butanediol, cyclopentanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol and mixtures thereof, preferably 1,4-butanediol, in an amount of 95 to 100 mol % (based on component (a1)). In addition to components (a1) and (a2), the synthesis of polybutylene adipate terephthalate can also use 0 to 5 mol %, preferably 0.05 to 4 mol % (based on component (a1)) of at least one compound D having at least three groups capable of forming esters. Compound D preferably contains 3 to 10 functional groups capable of forming ester bonds. Particularly preferred compounds D have 3 to 6 such functional groups in the molecule, in particular 3 to 6 hydroxyl and / or carboxyl groups. For example, tartaric acid, citric acid, malic acid, trimethylolpropane, trimethylolethane, pentaerythritol, polyether triol, glycerol, 1,3,5-benzene trimellitic acid, 1,2,4-benzene trimellitic acid, anhydride, 1,2,4,5-pyromellitic acid, dianhydride and hydroxyisophthalic acid.

[0016] The weight content T% of butylene terephthalate units in polybutylene adipate terephthalate (PBAT) is 35wt% to 65wt%. When T% is less than 35wt%, the product is too soft to be used, and when T% is higher than 65wt%, the product is too hard to be used. The viscosity range is 30 to 350g / ml, preferably 50 to 300g / ml (at 25°C, PBAT concentration is 0.5wt%, measured in 50:50w / w o-dichlorobenzene / phenol), and the melting point range is 50 to 170°C, preferably 60 to 160°C.

[0017] Polybutylene adipate terephthalate preferably includes polybutylene adipate terephthalate Ecoflex, polybutylene adipate terephthalate FLEX-262, polybutylene adipate terephthalate EBAG-262, polybutylene adipate terephthalate Ecoworld, and more preferably polybutylene adipate terephthalate Ecoworld. In the present invention, polybutylene adipate terephthalate Ecoflex is preferably provided by BASF of Germany; polybutylene adipate terephthalate FLEX-262 and polybutylene adipate terephthalate EBAG-262 are preferably provided by Guangdong Kingfa Technology; polybutylene adipate terephthalate Ecoworld is preferably provided by Shanxi Jinhui Zhaolong.

[0018] In one embodiment, the thermogravimetric analysis loss 10% temperature (TGA-10%) of the poly(butylene adipate terephthalate) used in the present invention is less than 400°C, more preferably less than 390°C, and most preferably less than 380°C.

[0019] In addition, the weight average molecular weight of the polybutylene adipate terephthalate in the present invention is generally in the range of 10,000 to 400,000, preferably in the range of 50,000 to 400,000, and more preferably in the range of 80,000 to 300,000. The weight average molecular weight of the polybutylene adipate terephthalate is calculated by using gel permeation chromatography (GPC), tetrahydrofuran as the solvent, and a differential refractive index detector (RI) as the detector, using styrene with a known molecular weight as a reference value.

[0020] <Polylactic acid>

[0021] The polylactic acid refers to two types: polylactic acid obtained by polycondensing only lactic acid as a raw material monomer; or polylactic acid obtained by polycondensing a lactic acid component and a hydroxycarboxylic acid component other than lactic acid (hereinafter also simply referred to as a hydroxycarboxylic acid component) as raw material monomers.

[0022] In the present invention, as the lactic acid component, only one optical isomer may be contained, or both may be contained. From the viewpoint of the balance between the flexibility and rigidity of the polylactic acid and the heat resistance, and the productivity during molding, it is preferred to use a lactic acid having a high optical purity containing one optical isomer as the main component. In addition, in this specification, the "main component" refers to a component containing 80 mol% or more in the lactic acid component.

[0023] From the above viewpoints, when only the lactic acid component is polycondensed, the content of the L-isomer (levorotatory; L-) or D-isomer (dexterotatory; D-) in the lactic acid component, that is, the content of the larger amount of any of the aforementioned isomers, is preferably 95.0 mol% or more, more preferably 98 mol% or more.

[0024] From the above viewpoints, the content of the L-isomer or D-isomer in the lactic acid component, i.e. the content of the larger one of the aforementioned isomers, is preferably 95.0 mol % or more, more preferably 98 mol % or more when polycondensing the lactic acid component and the hydroxycarboxylic acid component.

[0025] In addition, among the above-mentioned polylactic acids, in addition to polylactic acid obtained by condensing only the D form as lactic acid, polylactic acid obtained by condensing only the L form as lactic acid, and polylactic acid obtained by copolymerizing the D form and the L form, a material obtained by mixing polylactic acid whose main component is the L form and polylactic acid whose main component is the D form in any proportion can also be used.

[0026] On the other hand, as hydroxycarboxylic acid components other than lactic acid, hydroxycarboxylic acid compounds such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxyvaleric acid, hydroxycaproic acid, and hydroxyheptanoic acid can be listed, and these can be used alone or in combination of two or more. Among these hydroxycarboxylic acid components, glycolic acid and hydroxycaproic acid are preferred.

[0027] In addition, in the present invention, the dimer of the above-mentioned lactic acid and hydroxycarboxylic acid compound may also be included in each component. As the dimer of lactic acid, for example, the cyclic dimer of lactic acid, i.e., lactide, may be used. As the dimer of hydroxycarboxylic acid compound, for example, the cyclic dimer of glycolic acid, i.e., glycolide, may be used. Again, lactide includes the cyclic dimer of L-lactic acid (L-lactide), the cyclic dimer of D-lactic acid (D-lactide), the meso-lactide formed by the cyclic dimerization of D-lactic acid and L-lactic acid, and the racemic mixture DL-lactide of D-lactide and L-lactide. Any lactide may be used in the present invention, but from the viewpoint of the flexibility and rigidity of polylactic acid, and the productivity of polylactic acid resin during molding, D-lactide and L-lactide are preferably used. In addition, the dimer of lactic acid may be contained in the lactic acid component in any case of the case where only the lactic acid component is polycondensed or the case where the lactic acid component and the hydroxycarboxylic acid component are polycondensed.

[0028] The polycondensation reaction of only the lactic acid component and the polycondensation reaction of the lactic acid component and the hydroxycarboxylic acid component are not particularly limited, and a known method can be used.

[0029] In addition, the weight average molecular weight of the polylactic acid in the present invention is usually in the range of 10,000 to 400,000, preferably in the range of 50,000 to 400,000, and more preferably in the range of 80,000 to 300,000. That is, the reason is that when the weight average molecular weight of the polylactic acid is less than the above range, the mechanical properties of the resin molded product are low, and conversely, when the weight average molecular weight of the polylactic acid exceeds the above range, the fluidity during molding deteriorates. In addition, the weight average molecular weight of the polylactic acid is calculated using gel permeation chromatography (GPC), the solvent is tetrahydrofuran, the detector is a differential refractive index detector (RI), and styrene with a known molecular weight is used as a reference value.

[0030] In one embodiment, the thermogravimetric analysis loss 10% temperature (TGA-10%) of the polylactic acid used in the present invention is less than 360°C, more preferably less than 355°C, and most preferably less than 345°C.

[0031] The polylactic acid preferably includes one or more of polylactic acid LX175, polylactic acid L130, polylactic acid LX530, polylactic acid 4032D, polylactic acid 3001D, polylactic acid FY801, polylactic acid FY802, polylactic acid FY601 and polylactic acid REVODE110, and more preferably polylactic acid L175. In the present invention, polylactic acid LX175, polylactic acid L130, and polylactic acid LX530 are preferably provided by Total & Cobien of Thailand; polylactic acid 4032D, polylactic acid 3001D, and polylactic acid 2003D are preferably provided by NatureWorks of the United States; polylactic acid FY801, polylactic acid FY802, and polylactic acid FY601 are provided by Anhui Fengyuan; and polylactic acid REVODE110 is preferably provided by Zhejiang Hisun.

[0032] <Additives>

[0033] The additive may be a phenolic antioxidant. Alternatively, the additive may be a combination of a styrene-maleic anhydride copolymer and a phenolic antioxidant.

[0034] Phenolic antioxidants are primary antioxidants. Phenolic antioxidants refer to antioxidants having phenolic hydroxyl groups in the molecule, such as antioxidants having alkyl groups branched from the ortho position of the -OH group of the phenolic hydroxyl group. Phenolic antioxidants can be sterically hindered antioxidants, in which the phenol ring in the molecule is substituted with one or more alkyl groups, such as methyl, ethyl, isopropyl, tert-butyl, etc. There are no particular restrictions on phenolic antioxidants. In one embodiment, the phenolic antioxidant can be selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate, triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], tetrakis[methylene-3-(3,5-bis-tert-butyl-4-hydroxyphenyl)propionate]methane, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-6-methylbenzyl)-4-methylbenzyl In one embodiment, the phenolic antioxidant may be selected from at least one of the group consisting of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate and 3,5-di-tert-butyl-4-hydroxyphenylpropionate. The above phenolic antioxidants may be used alone or in combination.

[0035] Specific examples of commercially available phenolic antioxidants are 1010, 1076, 1098, 1425WL, 3114, 245 or 1135. The above-mentioned phenolic antioxidants may be used alone or in combination of two or more.

[0036] The content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3000 ppm relative to the total amount of the thermoplastic resin composition. Alternatively, the content of the phenolic antioxidant may be greater than or equal to 400 ppm and less than or equal to 2800 ppm relative to the total amount of the thermoplastic resin composition. Alternatively, the content of the phenolic antioxidant may be greater than or equal to 800 ppm and less than or equal to 2300 ppm relative to the total amount of the thermoplastic resin composition.

[0037] Styrene-maleic anhydride copolymer is a copolymer of styrene monomer and maleic anhydride monomer, for example, it can be a linear or branched random copolymer (random copolymers), a linear or branched block copolymer (block copolymers), etc. Styrene monomers can include styrene, α-methylstyrene, p-tert-butylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, α-methyl-p-methylstyrene, or bromostyrene, etc. The above-mentioned styrene monomers can be used alone or in combination. In one embodiment, the styrene monomer can be selected from one or more of styrene and α-methylstyrene. Maleic anhydride monomers can include maleic anhydride, itaconic anhydride, citraconic anhydride, or aconitic anhydride, etc. The above-mentioned maleic anhydride monomers can be used alone or in combination.

[0038] The additive may be a combination of styrene-maleic anhydride copolymer and a phenolic antioxidant. Compared to using only phenolic antioxidants as additives, using a combination of styrene-maleic anhydride copolymer and a phenolic antioxidant as an additive can further improve the physical properties, and can significantly increase the effects of tear resistance and tensile strength, especially the tensile strength in the width direction (TD direction) of the film and the tear strength in the long direction (MD direction). In the case of using a combination of styrene-maleic anhydride copolymer and a phenolic antioxidant as an additive, the total content of the additive is 1 to 5000 ppm, preferably 500 to 4000 ppm, and optimally 1000 to 3000 ppm relative to the total amount of the thermoplastic resin composition; the content of styrene-maleic anhydride copolymer is 1 to 2000 ppm, preferably 100 to 1500 ppm, and optimally 500 to 1000 ppm. The selection of the phenolic antioxidant is as described above, and the content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3000 ppm. The weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer must be less than 10,000, preferably less than 8,000, and most preferably less than 6,000; the weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer must be greater than 1,000, more preferably greater than 2,000, and most preferably greater than 3,000. The content of maleic anhydride monomer in the styrene-maleic anhydride copolymer is 20-55%, more preferably 25-50%, and most preferably 30-45%.

[0039] In a thermoplastic resin composition according to an embodiment of the present invention, the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 0.5:9.5, preferably 9.5:0.5 to 4:6, and most preferably 9:1 to 1:1. The molecular weight distribution index (weight average molecular weight / number average molecular weight (Mw / Mn)) of the thermoplastic resin composition according to an embodiment of the present invention is between 1.00 and 2.00, more preferably 1.50 to 2.00, and most preferably 1.80 to 2.00.

[0040] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 4:6, the additive is (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester or (a combination of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and styrene-maleic anhydride copolymer or a combination of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and styrene-maleic anhydride copolymer, the content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3000 ppm (compared to the total amount of the thermoplastic resin composition), and The weight average molecular weight of the styrene-maleic anhydride copolymer is less than 10,000, and the tensile strength of the film made of the thermoplastic resin composition in the width direction (TD direction) is greater than 20 MPa; when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the tear strength of the film in the long direction (MD direction) is greater than 1,650 MPa; when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, the tear strength of the film in the long direction (MD direction) is greater than 110 MPa. The film has different physical property requirements in the long direction (MD direction) and the width direction (TD direction). For example, in film applications, the MD direction needs to have stretchability, but the TD direction requires the processability of being able to be blown or biaxially stretched.

[0041] In a thermoplastic resin composition of one embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5-7:3, the additive is 400-2800 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or 1800-2300 ppm of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol (compared to the total amount of the thermoplastic resin composition), and the tear strength of the film made of the thermoplastic resin composition in the long direction (MD direction) is greater than 1650 MPa and the elongation of the film in the long direction (MD direction) is greater than 600%. The present invention can provide the film with excellent properties of having a stretching application in the MD direction and not being easy to cause tearing. In an embodiment of the thermoplastic resin composition, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, the additive is 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or 400 to 2800 ppm of n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (compared to the total amount of the thermoplastic resin composition), and the film made of the thermoplastic resin composition has a tear strength in the longitudinal direction (MD direction) greater than 110 MPa and a film elongation in the width direction (TD direction) greater than 26.5%. For example, in film applications, the MD direction is required to have stretchability, but the TD direction requires processability that can be blown or biaxially stretched.

[0042] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additive is 400 to 2800 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (compared to the total amount of the thermoplastic resin composition), and the tensile strength of the film made of the thermoplastic resin composition in the longitudinal direction (MD direction) is greater than 33 MPa. For example, in film applications, plastic bags need to have load-bearing properties in the MD direction without breaking.

[0043] In a thermoplastic resin composition of an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, the additive is 1800 to 2300 ppm of (tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester or β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl ester (compared to the total amount of the thermoplastic resin composition), and the tensile strength of the film made of the thermoplastic resin composition in the longitudinal direction (MD direction) is greater than 33 MPa. For example, in film applications, plastic bags need to have load-bearing properties in the MD direction without breaking.

[0044] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additives are 800 to 1300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 100 to 1500 ppm of styrene-maleic anhydride copolymer (compared to the total amount of the thermoplastic resin composition), the weight average molecular weight of the styrene-maleic anhydride copolymer is less than 10,000, and the tensile strength of a film made from the thermoplastic resin composition in the width direction (TD direction) is greater than 20 MPa, and the tear strength of the film in the longitudinal direction (MD direction) is greater than 1650 MPa.

[0045] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of the polybutylene adipate terephthalate to the polylactic acid is 9.5:0.5 to 7:3, the temperature of thermogravimetric analysis loss of 10% (TGA-10%) of the additive of 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (compared to the total amount of the thermoplastic resin composition) can reach 358° C. or above When the temperature difference is greater than 1.6°C or the weight ratio of polybutylene adipate terephthalate to the polylactic acid is 6:4 to 4:6, the temperature at which the thermogravimetric analysis loss of 10% (TGA-10%) of the additive of 400 to 2800 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (compared to the total amount of the thermoplastic resin composition) can reach 343°C or above and the temperature difference is greater than 13°C.

[0046] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additive is 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (relative to the total amount of the thermoplastic resin composition), and the temperature at which the thermogravimetric analysis loses 10% (TGA-10%) can reach 358° C. or above, and the temperature difference is greater than 1.6° C.

[0047] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, the additive is 400 to 2800 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and (compared to the total amount of the thermoplastic resin composition) the tear strength of a film made of the thermoplastic resin composition in the longitudinal direction (MD direction) is greater than 110 MPa.

[0048] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, the additive is 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and the temperature at which the thermogravimetric analysis loss of 10% (TGA-10%) (compared to the total amount of the thermoplastic resin composition) can reach 343° C. or above and the temperature difference is greater than 13° C.

[0049] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additives are 800 to 1300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 100 to 1500 ppm of styrene-maleic anhydride copolymer (compared to the total amount of the thermoplastic resin composition), and the weight average molecular weight of the styrene-maleic anhydride copolymer is less than 10,000, the thermogravimetric analysis loss 10% temperature (TGA-10%) of the thermoplastic resin can reach above 365° C. and the temperature difference can be greater than 8° C.

[0050] In one embodiment, in addition to the above-mentioned polybutylene adipate terephthalate, polylactic acid, and additives, the thermoplastic resin composition may further include other components such as a modifier, a colorant, etc. In one embodiment, the thermoplastic resin composition is composed of polybutylene adipate terephthalate, polylactic acid, and additives.

[0051] The present invention provides a method for preparing a thermoplastic resin composition. The method comprises passing the above-mentioned polybutylene adipate terephthalate, the above-mentioned polylactic acid, and the above-mentioned additives through a molding device to mix the polybutylene adipate terephthalate, the polylactic acid, and the additives to obtain a solid thermoplastic resin composition. The molding device may include a dryer, and / or a stirrer, and / or a mixer, and / or an extruder, and / or an injection molding machine, and / or a pelletizer, and / or a film machine, etc. The thermoplastic resin composition has the above-mentioned composition and content range. The relative proportion and / or content of polybutylene adipate terephthalate, polylactic acid, and the additives may remain substantially unchanged before and after passing through the molding device.

[0052] The thermoplastic resin composition of the present invention can be used for degradable plastic products. In some embodiments, the thermoplastic resin composition of the present invention can be used as a plastic film. The plastic film can be composed of the aforementioned thermoplastic resin composition, for example, a blown film molding process can be used. For example, the thermoplastic resin composition can be plasticized and melted, and the molten thermoplastic resin composition can be extruded and blown into a film bubble of a certain size at a certain pressure and speed, and then cooled and / or stretched to make a plastic film. The tensile strength and elongation are tested according to ISO 527, and the tear strength is tested according to ISO 6838. The plastic film of the present invention can be used for at least one of plastic bags, shopping bags and agricultural films. The thermoplastic resin composition of the present invention can be applied to molding methods such as injection molding, compression molding, extrusion molding, blow molding, vacuum molding and hollow molding to make plastic products.

[0053] The present invention is described below through a plurality of examples and comparative examples. However, the present invention is not limited to the components, contents, proportions, etc. disclosed in the following examples.

[0054] <Preparation of thermoplastic resin composition>

[0055] The monomers and additives used in the following examples and comparative examples are as follows:

[0056] Polybutylene adipate terephthalate (PBAT): Brand BASF C1200, Mn: 55,719, Mw: 125703, TGA-10%: 374.0℃

[0057] Polylactic acid (PLA): Brand: Natureworks 2003D, Mn: 117,210, Mw: 213,023, TGA-10%: 340.3°C.

[0058] additive:

[0059] (1) Phenolic antioxidants:

[0060] (Tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester: Brand 1010.

[0061] β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester: Brand 1076.

[0062] (2) Non-phenolic antioxidants:

[0063] Tris(2,4-di-sec-butylphenyl)phosphite: Brand 168.

[0064] 2-{1-[2-Hydroxy-3,5-bis(2-methylbutan-2-yl)phenyl]ethyl}-4,6-bis(2-methylbutan-2-yl)phenyl acrylate: brand GS.

[0065] (3) Styrene-maleic anhydride copolymer:

[0066] Brand: XIRAN1000P, weight average molecular weight: 3385, maleic anhydride monomer content: 42%.

[0067] Brand: XIRAN4000, weight average molecular weight: 10536, maleic anhydride monomer content: 24%.

[0068] According to the components, contents and / or proportions of Tables 1, 2, 3 and 4 below, polybutylene adipate terephthalate, polylactic acid and additives were passed through a molding device to obtain thermoplastic resin compositions of Examples 1 to 10 and Comparative Examples 1 to 24.

[0069] <Preparation of plastic film>

[0070] The thermoplastic resin composition was made into a plastic film by using a film blowing process, and the film thickness was 25 μm.

[0071] <Evaluation of thermoplastic resin composition>

[0072] The number average molecular weight and weight average molecular weight are calculated by gel permeation chromatography (GPC) analysis, using tetrahydrofuran as the solvent and a differential refractive index detector (RI) as the detector, using styrene with a known molecular weight as a reference value. The column model is Agilent / Part No.PL1110-6520 / PLgel 5μm 300x 7.5mm; PartNo.PL1110-6525 / PLgel5μm 300x 7.5mm; Part No.PL1110-6530 / PLgel 5μm 300x7.5mm; Part No.PL1110-6540 / PLgel 5μm 300x 7.5mm. The crystallization temperature (Tc) of the thermoplastic resin composition of the embodiment and the comparative example was measured by a differential scanning calorimeter (DSC), model TA / Q2000. Thermogravimetric analysis (TGA) model is TA / Q5000. In the present invention, the temperature at which the sample loses 10% of its weight due to heat under nitrogen is recorded, and the symbol is TGA-10%. The crystallinity (Xc) is calculated according to the following formula 1. In the following formula 1, ΔHm is the melting enthalpy (J / g), ΔHcc is the cold crystallization enthalpy (J / g), and ΔHm of polybutylene adipate terephthalate is 0 is 114 J / g, and the ΔHm of polylactic acid 0 is 93.6 J / g, is the ratio of polybutylene adipate terephthalate or polylactic acid to the total weight of polybutylene adipate terephthalate and polylactic acid. The evaluation results are listed in Tables 1 to 7 below.

[0073]

[0074] <Evaluation of plastic films>

[0075] The film thickness was 25 μm, and the tensile strength and elongation were tested according to ISO 527, and the tear strength was tested according to ISO 6838. The tensile properties of the plastic films composed of the thermoplastic resin compositions of Examples 1 to 10 and Comparative Examples 1 to 14 were evaluated. The evaluation results are listed in Tables 1 and 2 below.

[0076] [Table 1]

[0077]

[0078]

[0079] [Table 2]

[0080]

[0081] [Table 2 continued]

[0082]

[0083]

[0084] As shown in Tables 1 and 2, when the thermoplastic resin composition comprises PBAT, PLA and an additive, wherein the additive is a phenolic antioxidant or a combination of a styrene-maleic anhydride copolymer and a phenolic antioxidant, the weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer is less than 10,000, and the content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3,000 ppm (relative to the total amount of the thermoplastic resin composition), better physical properties can be obtained. The data show that the tensile strength is significantly improved, especially the tensile strength in the film width direction (TD direction), which is more than 20 MPa, and when the weight ratio of PBAT to PLA is 9.5:0.5 to 7:3, the tear strength in the long direction (MD direction) of the film is greater than 1650 MPa; when the weight ratio of PBAT to PLA is 6:4 to 4:6, the tear strength in the long direction (MD direction) of the film is greater than 110 MPa. The long direction (MD direction) and the width direction (TD direction) of the film have different physical property requirements due to the differences in application and use. For example, in film applications, the MD direction needs to have stretchability, but the TD direction requires the ability to be blown or biaxially stretched, but the tear strength requirement is relatively low.

[0085] In addition, the data show that when styrene-maleic anhydride copolymer and phenolic antioxidant are used together as additives, the tear strength is more significantly improved than when only phenolic antioxidant is used.

[0086] As shown in Tables 1 and 2, when the weight ratio of polybutylene adipate terephthalate to polylactic acid in the thermoplastic resin composition is 9.5:0.5-7:3, and the additive is 400-2800 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or 1800-2300 ppm of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol (compared to the total amount of the thermoplastic resin composition), the film made of the thermoplastic resin composition has a tear strength in the longitudinal direction (MD direction) greater than 1650 MPa and a film elongation in the longitudinal direction (MD direction) greater than 600%. The present invention can provide the film with excellent properties of being stretchable in the MD direction and not easily torn. This property is extremely important for applications such as films or plastic bags.

[0087] In a thermoplastic resin composition of an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, the additive is 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or 400 to 2800 ppm of n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (compared to the total amount of the thermoplastic resin composition), and the tear strength of the film made of the thermoplastic resin composition in the longitudinal direction (MD direction) is greater than 110 MPa and the elongation in the width direction (TD direction) of the film is greater than 26.5%. For example, in film applications, the MD direction needs to have stretchability, but the TD direction requires processability that can be blown or biaxially stretched.

[0088] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additive is 400 to 2800 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (compared to the total amount of the thermoplastic resin composition), and the tensile strength of the film made of the thermoplastic resin composition in the longitudinal direction (MD direction) is greater than 33 MPa. For example, in film applications, plastic bags need to have load-bearing properties in the MD direction without breaking.

[0089] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, the additive is 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (compared to the total amount of the thermoplastic resin composition), and the tensile strength of the film made of the thermoplastic resin composition in the longitudinal direction (MD direction) is greater than 33 MPa. For example, in film applications, plastic bags need to have load-bearing properties in the MD direction without breaking.

[0090] In a thermoplastic resin composition according to an embodiment of the present invention, when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additives are 800 to 1300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 100 to 1500 ppm of styrene-maleic anhydride copolymer (compared to the total amount of the thermoplastic resin composition), the weight average molecular weight of the styrene-maleic anhydride copolymer is less than 10,000, and the tensile strength of a film made from the thermoplastic resin composition in the width direction (TD direction) is greater than 20 MPa, and the tear strength of the film in the length direction (MD direction) is greater than 1650 MPa.

[0091] As shown in Table 1, in the thermoplastic resin compositions of Examples 9-10, the additives include a phenolic antioxidant and a styrene-maleic anhydride copolymer. Compared with Examples 1 and 3 in which only a phenolic antioxidant is added as an additive, the tear strength and tensile strength of the plastic films formed by the thermoplastic resin compositions of Examples 9-10 in the long direction (MD direction) or the width direction (TD direction) are significantly improved. For example, the tear strength in the long direction (MD direction) is greater than 1800 MPa, the tear strength in the width direction (TD direction) is greater than 580 MPa, and the tensile strength in the width direction (TD direction) is greater than 22 MPa.

[0092] As shown in Table 2, in the thermoplastic resin compositions of Comparative Examples 11-12, the additives are only styrene-maleic anhydride copolymers without phenolic antioxidants, resulting in the plastic film having a tear strength in the longitudinal direction (MD direction) of less than 1650 MPa, which is significantly lower than that of Example 1 or Example 9. In the thermoplastic resin compositions of Comparative Examples 13-14, although the additives contain styrene-maleic anhydride copolymers and phenolic antioxidants, the weight average molecular weight (Mw) of the styrene-maleic anhydride copolymers is greater than 10,000, resulting in the failure to simultaneously satisfy the requirements of the plastic film having a tear strength in the longitudinal direction (MD direction) of greater than 1650 MPa and a tensile strength in the width direction (TD direction) of the film of greater than 20 MPa.

[0093] [Table 3]

[0094]

[0095] As shown in Table 3, when the additive in the thermoplastic resin composition is a phenolic antioxidant, and the content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3000 ppm, better physical property results can be obtained, for example, the molecular weight distribution index (Q) is less than 2.0, indicating that the resin has excellent miscibility and can obtain balanced physical property results.

[0096] As shown in Table 3, if a non-phenolic antioxidant is selected as an additive in the thermoplastic resin composition, even if the added amount is greater than or equal to 1 ppm and less than 3000 ppm, the number average molecular weight (Mn) of the thermoplastic resin composition is relatively low; the molecular weight distribution index (Q) is relatively high; and the resin crystallization temperature (Tc) is relatively low. This indicates that the resin has poor miscibility, resulting in poor crystallization properties and failure to obtain balanced physical property results.

[0097] [Table 4]

[0098]

[0099] [Table 5]

[0100]

[0101] [Table 6]

[0102]

[0103] [Table 7]

[0104]

[0105] From the data in Table 4, it can be seen that PBAT and phenolic antioxidants alone or PLA and phenolic antioxidants alone cannot effectively improve thermal stability (TGA-10%). The thermal stability of 1076 has decreased. Moreover, using only PLA without PBAT will result in poor tear resistance, slow crystallization rate, low crystallinity, low heat deformation temperature and other problems, making it difficult to meet the market technical requirements of the film; using only PBAT without PLA will result in low strength and low modulus.

[0106] From the data in Tables 4 to 7, it can be seen that PBAT needs to be used in combination with PLA and a phenolic antioxidant, or PBAT needs to be used in combination with PLA and a phenolic antioxidant and styrene-maleic anhydride copolymer to effectively improve thermal stability (TGA-10%).

[0107] It can be seen from the data in Tables 4 to 7 that when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additive is 1800 to 2300 ppm of (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate or β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl alcohol (compared to the total amount of the thermoplastic resin composition), the temperature at which the thermogravimetric analysis loses 10% (TGA-10%) can reach above 358°C and the temperature difference is greater than 1.6°C.

[0108] It can be seen from the data in Tables 4 to 7 that when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, and the additive is 400 to 2800 ppm of (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol (compared to the total amount of the thermoplastic resin composition), the temperature at which the thermogravimetric analysis loses 10% (TGA-10%) can reach above 343°C and the temperature difference is greater than 13°C.

[0109] It can be seen from the data in Tables 4 to 7 that when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additive is 800 to 1300 ppm of (tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester and 100 to 1500 ppm of styrene-maleic anhydride copolymer (compared to the total amount of the thermoplastic resin composition), and the weight average molecular weight of the styrene-maleic anhydride copolymer is less than 10,000, then the thermogravimetric analysis loss 10% temperature (TGA-10%) of the thermoplastic resin can reach above 365°C and the temperature difference can be greater than 8°C.

[0110] The present invention provides a thermoplastic resin composition comprising polybutylene adipate terephthalate, polylactic acid and an additive, a method for preparing the thermoplastic resin composition and a use of a plastic film composed of the thermoplastic resin composition. By using one of the group consisting of a phenolic antioxidant, a styrene-maleic anhydride copolymer and a phenolic antioxidant as an additive, wherein the weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer is less than 10,000, and the content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3,000 ppm, the thermoplastic resin composition of the present invention has balanced physical properties such as good heat resistance, excellent tensile strength and good crystallinity.

[0111] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A thermoplastic resin composition, characterized in that Include: Polybutylene adipate terephthalate (PBAT); Polylactic acid (PLA); and An additive, wherein the additive is selected from one of the group consisting of a phenolic antioxidant and a styrene-maleic anhydride copolymer and a phenolic antioxidant, The weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer is less than 10,000, and the content of the phenolic antioxidant is greater than or equal to 1 ppm and less than 3,000 ppm.

2. The thermoplastic resin composition as claimed in claim 1, wherein the content of the phenolic antioxidant is greater than or equal to 400 ppm and less than or equal to 2800 ppm, wherein the weight ratio of the polybutylene adipate terephthalate to the polylactic acid is 9.5:0.5 to 0.5:9.

5. 3 . The thermoplastic resin composition according to claim 2 , wherein the content of the phenolic antioxidant is greater than or equal to 800 ppm and less than or equal to 2300 ppm.

4. The thermoplastic resin composition as claimed in claim 1, wherein the content of the styrene-maleic anhydride copolymer is 1-2000 ppm, wherein the content of the maleic anhydride monomer in the styrene-maleic anhydride copolymer is 20-55%. 5 . The thermoplastic resin composition as claimed in claim 1 , wherein the weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer is less than 6,000.

6. The thermoplastic resin composition as claimed in claim 1, wherein the phenolic antioxidant is at least one selected from the group consisting of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate and isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate.

7. The thermoplastic resin composition as claimed in claim 1, wherein the weight ratio of the polybutylene adipate terephthalate to the polylactic acid is 9.5:0.5-4:6, and the additive is pentaerythritol [di-tert-butyl-4-hydroxyphenyl) propionate or β-(3,5--4-hydroxyphenyl) propionate octadecyl alcohol or a combination of pentaerythritol [tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and styrene-maleic anhydride copolymer or a combination of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and styrene-maleic anhydride copolymer.

8. The thermoplastic resin composition of claim 1, wherein when the weight ratio of polybutylene adipate terephthalate to polylactic acid is 9.5:0.5 to 7:3, the additive is 800 to 1300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 100 to 1500 ppm of styrene-maleic anhydride copolymer, relative to the total amount of the thermoplastic resin composition.

9. The thermoplastic resin composition of claim 1, wherein the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, and the additive is 1800 to 2300 ppm of n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate relative to the total amount of the thermoplastic resin composition.

10. The thermoplastic resin composition according to claim 1, wherein the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, and the additive is 400 to 2800 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate based on the total amount of the thermoplastic resin composition.

11. The thermoplastic resin composition as claimed in claim 1, wherein when the weight ratio of the polybutylene adipate terephthalate to the polylactic acid is 9.5:0.5 to 7:3, the additive is 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, relative to the total amount of the thermoplastic resin composition.

12. The thermoplastic resin composition according to claim 1, wherein the weight ratio of polybutylene adipate terephthalate to polylactic acid is 6:4 to 4:6, and the additive is 1800 to 2300 ppm of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate or n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, relative to the total amount of the thermoplastic resin composition.

13. The thermoplastic resin composition as claimed in claim 1, wherein when the weight ratio of the polybutylene adipate terephthalate to the polylactic acid is 9.5:0.5 to 7:3, the content of pentaerythritol (tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) is greater than or equal to 400 ppm and less than or equal to 2800 ppm, or the content of n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is greater than or equal to 1800 ppm and less than or equal to 2300 ppm.

14. A method for preparing a thermoplastic resin composition, characterized in that: Include: Polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), and additives are passed through a molding device to obtain a thermoplastic resin composition. The additive is selected from the group consisting of phenolic antioxidants and styrene-maleic anhydride copolymers and phenolic antioxidants. The weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer is less than 10,000, and the content of the phenolic antioxidant in the thermoplastic resin composition is greater than or equal to 1 ppm and less than 3,000 ppm.

15. Use of a plastic film, wherein the plastic film is composed of the thermoplastic resin composition according to any one of claims 1 to 13, and the plastic film is used for at least one of a plastic bag, a shopping bag and an agricultural film.

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