KR102410624B1 - Biodegradable polyester resin composition, biodegradable polyester film and preperation method thereof - Google Patents

Abstract

The embodiment relates to a biodegradable polyester resin composition with improved biodegradability, cold resistance, strength and processability by including a specific diol component and a dicarboxylic acid component, a biodegradable polyester film, and a method for manufacturing the same, the polyester resin composition Compared to conventionally used biodegradable polymer resins, biodegradability, cold resistance, strength and processability can all be improved, so it can be applied to various fields such as films, packaging materials, and nonwovens to exhibit excellent properties.

Description

Biodegradable polyester resin composition, biodegradable polyester film, and manufacturing method thereof

Embodiments relate to a biodegradable polyester resin composition, a biodegradable polyester film, and a method for preparing the same.

Recently, as concerns about environmental problems increase, a solution to the problem of processing various household items, in particular, disposable products is required. Specifically, polymer materials are inexpensive and have excellent properties such as processability, so they are widely used to manufacture various products such as films, fibers, packaging materials, bottles, and containers. It has the disadvantage that it takes hundreds of years for the material to be discharged and completely decomposed in nature.

In order to overcome the limitations of these polymers, research on biodegradable polymers that decompose in a much faster time is being actively conducted. Polylactic acid (PLA), polybutyleneadipate terephthalate (PBAT), and polybutylene succinate (PBS) are used as biodegradable polymers, but PLA is The impact strength is weak, PBAT has low price competitiveness and tensile strength, and the elongation is high, so the toughness is poor. PBS has rigidity but low tear strength. In particular, excellent cold resistance and impact resistance are required in order to be applied as a packaging material for processed foods stored and transported at low temperatures, and these polymers have a problem in that mechanical properties are further deteriorated as the temperature goes down.

A method of blending biodegradable polymers has been attempted to overcome these physical limitations, but the degree of improvement in physical properties through blending is not large, so research on biodegradable polymers having physical properties applicable to various fields is required.

For example, Korean Patent Application Laid-Open No. 2012-0103158 discloses a biodegradable plastic composition in which durability is improved by mixing polypropylene carbonate (PPC) with a composition containing PLA, PBS, etc., but cold resistance and Impact resistance is still low.

Korean Patent Publication No. 2012-0103158

Accordingly, embodiments are to provide a biodegradable polyester resin composition capable of improving all of biodegradability, cold resistance, strength and processability, a biodegradable polyester film, and a manufacturing method thereof.

The biodegradable polyester resin composition according to an embodiment includes a diol component and a dicarboxylic acid component including propanediol or a derivative thereof, and the dicarboxylic acid component includes a first dicarboxylic acid and the first dicarboxylic acid. a second dicarboxylic acid different from carboxylic acid, wherein the first dicarboxylic acid includes at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, and derivatives thereof, wherein the second dicarboxylic acid is It contains at least one selected from the group consisting of dipic acid, succinic acid, and derivatives thereof.

A biodegradable polyester film according to another embodiment is a biodegradable polyester film formed from a biodegradable polyester resin composition, wherein the biodegradable polyester resin composition includes a diol component and a dicarboxylic acid component including propanediol or a derivative thereof. wherein the dicarboxylic acid component comprises a first dicarboxylic acid and a second dicarboxylic acid different from the first dicarboxylic acid, wherein the first dicarboxylic acid is terephthalic acid, dimethyl terephthalate and these At least one selected from the group consisting of derivatives of, and the second dicarboxylic acid includes at least one selected from the group consisting of adipic acid, succinic acid, and derivatives thereof.

A method for producing a biodegradable polyester film according to another embodiment includes preparing a prepolymer by esterifying a composition including a diol component and a dicarboxylic acid component including propanediol or a derivative thereof; preparing a polymer by subjecting the prepolymer to a polycondensation reaction; preparing pellets from the polymer; and drying and melt-extruding the pellets, wherein the dicarboxylic acid component includes a first dicarboxylic acid and a second dicarboxylic acid different from the first dicarboxylic acid, The dicarboxylic acid includes at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, and derivatives thereof, and the second dicarboxylic acid includes at least one selected from the group consisting of adipic acid, succinic acid, and derivatives thereof. include

The biodegradable polyester resin composition according to the embodiment can improve strength and processability, in particular, cold resistance and impact resistance, without inhibiting biodegradability by including a specific diol component and a dicarboxylic acid component, so that more diverse fields can be applied to exhibit excellent properties.

Accordingly, the biodegradable polyester film according to the embodiment is formed from the biodegradable polyester resin composition, and thus has excellent quality when applied as a packaging material for products stored and transported at low temperatures.

Hereinafter, the invention will be described in detail through embodiments. The embodiments are not limited to the contents disclosed below and may be modified in various forms as long as the gist of the invention is not changed.

In the present specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, it should be understood that all numerical ranges indicating physical property values, dimensions, etc. of the components described in the present specification are modified by the term "about" in all cases unless otherwise specified.

In this specification, terms such as first, second, etc. are used to describe various components, and the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Biodegradable polyester resin composition

The biodegradable polyester resin composition according to an embodiment includes a diol component and a dicarboxylic acid component including propanediol or a derivative thereof, and the dicarboxylic acid component includes a first dicarboxylic acid and the first dicarboxylic acid. a second dicarboxylic acid different from carboxylic acid, wherein the first dicarboxylic acid includes at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, and derivatives thereof, wherein the second dicarboxylic acid is It contains at least one selected from the group consisting of dipic acid, succinic acid, and derivatives thereof.

The diol component includes propanediol or a derivative thereof. Specifically, the diol component may include 1,3-propanediol or 1,2-propanediol, and 1,3-propanediol is more preferable in terms of molecular structure.

More specifically, looking at the molecular structure through the rotation of a carbon-carbon single bond in the stereochemical structure of 1,3-propanediol and 1,2-propanediol, 1,3-propanediol is trans-goushi-goushi - By changing into trans (trans-gauche-gauche-trans) form, it has a spring-like structure, so it has excellent flexibility and can be easily deformed, so it has superior elongation and elastic recovery compared to 1,2-propanediol. Therefore, when 1,3-propanediol is included as the diol component, cold resistance and impact resistance may be further improved.

The diol component is 40 mol% or more, 45 mol% or more, 50 mol% or more, 55 mol% or more, 60 mol% or more, 80 mol% or more, 85 mol% or more, 95 mol% based on the total number of moles of the diol component. or more, 98 mol% or more, 99 mol% or more, or 100 mol% of propanediol or a derivative thereof. When the diol component includes propanediol or a derivative thereof, biodegradability, strength, cold resistance, and impact resistance can be improved. In particular, when the diol component is composed only of 1,3-propanediol, impact resistance can be maximized can

In addition, the diol component may include a second diol different from the first diol that is the propanediol or a derivative thereof.

The second diol may be at least one selected from the group consisting of butanediol, hexanediol, cyclohexanedimethanol, and ethylene glycol. Specifically, the second diol is 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4- Hexanediol, 1,6-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 2,6-hexanediol, 3,4-hexanediol, 1,2-cyclo It may be at least one selected from the group consisting of hexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, or ethylene glycol. More specifically, 1,4-butanediol is preferable in terms of cold resistance and flexibility, but is not limited thereto.

The diol component may include 30 mol% to 70 mol% of the second diol based on the total number of moles of the diol component. For example, the diol component may include 30 mol% to 65 mol%, 30 mol% to 60 mol%, or 32 mol% to 55 mol% of the second diol based on the total number of moles of the diol component.

By including the first diol and the second diol different from the first diol, the diol component can improve the biodegradability, strength, cold resistance, and impact resistance of the biodegradable polyester resin, and in particular, maximize cold resistance and pinhole resistance. Therefore, it can have excellent properties when applied as a packaging material for products stored and transported at low temperatures.

According to one embodiment, the first diol may be propanediol, and the second diol may be butanediol. Specifically, when the first diol is 1,3-propanediol and the second diol is 1,4-butanediol, it may be most preferable in terms of cold resistance and impact resistance.

The molar ratio of the first diol to the second diol may be 0.5 to 3:1. For example, the molar ratio of the first diol to the second diol may be 0.5 to 2.5:1, 0.7 to 2.2:1, or 1.1 to 2.2:1. When the molar ratio of the first diol and the second diol satisfies the above range, biodegradability, strength, cold resistance, and impact resistance may be improved, and in particular, cold resistance and pinhole resistance may be maximized.

The dicarboxylic acid component comprises a first dicarboxylic acid and a second dicarboxylic acid different from the first dicarboxylic acid.

The first dicarboxylic acid includes at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, and derivatives thereof. Specifically, the first dicarboxylic acid may be terephthalic acid or dimethyl terephthalate.

In addition, the dicarboxylic acid component is 45 mol% or more, 50 mol% or more, 55 mol% or more, 60 mol% or more, 70 mol% or more, 45 mol% to 80 mol% based on the total number of moles of the dicarboxylic acid component mole %, 45 mole % to 75 mole % or 50 mole % to 70 mole % of the first dicarboxylic acid.

The second dicarboxylic acid includes at least one selected from the group consisting of adipic acid, succinic acid, and derivatives thereof. Specifically, the second dicarboxylic acid may be adipic acid or succinic acid.

In addition, the dicarboxylic acid component is 30 mol% or more, 35 mol% or more, 40 mol% or more, 45 mol% or more, 50 mol% or more, 55 mol% or more, based on the total number of moles of the dicarboxylic acid component; 60 mol% or more, 70 mol% or more, 30 mol% to 80 mol%, 35 mol% to 75 mol%, 30 mol% to 70 mol%, 35 mol% to 65 mol%, 35 mol% to 60 mol%, 35 mol% to 55 mol%, 45 mol% to 80 mol%, 45 mol% to 75 mol% or 50 mol% to 70 mol% of the second dicarboxylic acid.

The molar ratio of the first dicarboxylic acid to the second dicarboxylic acid may be 0.5 to 3:1. For example, the molar ratio of the first dicarboxylic acid to the second dicarboxylic acid may be 0.5 to 2.5:1, 0.7 to 2:1, or 0.8 to 1.9:1. When the molar ratio of the first dicarboxylic acid and the second dicarboxylic acid satisfies the above range, biodegradability and processability may be improved.

In addition, the molar ratio of the diol component to the dicarboxylic acid component may be 1 to 2:1. For example, the molar ratio of the diol component to the dicarboxylic acid component may be 1 to 1.8:1, 1.2 to 1.8:1, or 1.2 to 1.6:1. Since the molar ratio of the diol component and the dicarboxylic acid component satisfies the above range, biodegradability, strength, and processability can all be improved without discoloration such as yellowing, and thus it is easy to apply to various fields.

The biodegradable polyester resin composition may further include a titanium-based catalyst or a germanium-based catalyst. Specifically, the biodegradable polyester resin is one or more titanium-based catalysts selected from the group consisting of titanium isopropoxide, dibutyltin oxide, tetrapropyl titanate, tetrabutyl titanate and tetraisopropyl titanate, or germanium It may include at least one germanium-based catalyst selected from the group consisting of oxide, germanium methoxide, germanium ethoxide, tetramethyl germanium, tetraethyl germanium and germanium sulfide. In addition, the biodegradable polyester resin composition may include one or more catalysts selected from the group consisting of antimony trioxide, antimony acetate, calcium acetate and magnesium acetate.

In addition, the content of the catalyst may be 100 ppm to 1,000 ppm based on the total weight of the composition. For example, the biodegradable polyester resin composition is 100 ppm to 800 ppm, 150 ppm to 700 ppm, 200 ppm to 500 ppm or 250 ppm to 450 ppm of a titanium-based catalyst or a germanium-based catalyst based on the total weight of the composition may include When the content of the catalyst satisfies the above range, processability can be improved without discoloration such as yellowing.

molded product

Embodiments may provide a molded article prepared from the biodegradable polyester resin composition.

Specifically, the molded article may be manufactured by molding the biodegradable polyester resin composition by a method known in the art, such as extrusion and injection, and the molded article may be an injection molded article, an extrusion molded article, a thin film molded article, or a blow molded article, The present invention is not limited thereto.

For example, the molded article may be in the form of a film or sheet that can be used as an agricultural mulching film, disposable gloves, food packaging, etc., and may be in the form of a fiber that can be used as a fabric, knitted fabric, non-woven fabric, rope, etc., and a lunch box It may be in the form of a container that can be used as a container for food packaging, such as.

In particular, since the molded article can be formed from the polyester resin composition that can improve strength and processability, in particular, cold resistance and impact resistance, it is excellent when applied as a packaging material for products stored and transported at low temperatures or packaging materials for medical products. characteristics can be exhibited.

biodegradable polyester film

A biodegradable polyester film according to another embodiment is a biodegradable polyester film formed from a biodegradable polyester resin composition, wherein the biodegradable polyester resin composition includes a diol component and a dicarboxylic acid component including propanediol or a derivative thereof. wherein the dicarboxylic acid component comprises a first dicarboxylic acid and a second dicarboxylic acid different from the first dicarboxylic acid, wherein the first dicarboxylic acid is terephthalic acid, dimethyl terephthalate and these At least one selected from the group consisting of derivatives of, and the second dicarboxylic acid includes at least one selected from the group consisting of adipic acid, succinic acid, and derivatives thereof.

The thickness of the biodegradable polyester film may be 5 μm to 200 μm. For example, the biodegradable polyester film may have a thickness of 5 μm to 180 μm, 5 μm to 160 μm, 10 μm to 150 μm, or 15 μm to 130 μm.

The number of pinholes after the pinhole resistance test of the biodegradable polyester film may be 15 or less. Pinhole resistance refers to the property that the film does not easily puncture. For example, the number of pinholes after the pinhole resistance test of the biodegradable polyester film may be 13 or less, 10 or less, 1 to 15, or 1 to 10.

In addition, the unit impact absorption energy of the biodegradable polyester film may be 1.0 kgf-cm / ㎛ or more. For example, the unit impact absorption energy of the biodegradable polyester film may be 1.2 kgf-cm / ㎛ or more or 1.4 kgf-cm / ㎛ or more.

The puncture resistance of the biodegradable polyester film may be 0.5 kgf or more. For example, the puncture resistance of the biodegradable polyester film may be 0.6 kgf or more or 0.8 kgf or more.

The number of pinholes after the pinhole resistance test of the biodegradable polyester film, unit impact absorption energy and puncture resistance satisfy the above ranges, so that strength and flexibility can be improved, and in particular, impact resistance can be maximized.

The storage modulus (E') of the biodegradable polyester film may be 0.2 x 10 ⁹ Pa to 4.0 x 10 ⁹ Pa. Specifically, the average value of the storage modulus (E') of the biodegradable polyester film in the temperature range of -20 °C to 5 °C is 0.2 x 10 ⁹ Pa to 3.8 x 10 ⁹ Pa, 0.5 x 10 ⁹ Pa to 3.5 x 10 ⁹ Pa or 0.8 x 10 ⁹ Pa to 3.5 x 10 ⁹ Pa.

In addition, the amount of change (ΔE') of the storage modulus of the biodegradable polyester film may be 0.01 x 10 ⁹ Pa to 0.4 x 10 ⁹ Pa. Specifically, the amount of change (ΔE') of the storage modulus of the biodegradable polyester film in the temperature range of -20°C to 20°C is 0.01 x 10 ⁹ Pa to 0.35 x 10 ⁹ Pa, 0.03 x 10 ⁹ Pa to 0.35 x 10 ⁹ Pa or 0.04 x 10 ⁹ Pa to 0.33 x 10 ⁹ Pa.

By satisfying the range of the storage modulus and the amount of change in the storage modulus of the biodegradable polyester film, durability and impact resistance, in particular, cold resistance can be maximized. Specifically, when the storage elastic modulus of the biodegradable polyester film exceeds the above range, the film may be easily torn, so durability and impact resistance may be reduced.

In addition, the thermal adhesive strength of the biodegradable polyester film may be 700 gf / inch or more. For example, the thermal adhesive strength of the biodegradable polyester film may be 750 gf / inch or more, 800 gf / inch or more, or 900 gf / inch or more.

The haze of the biodegradable polyester film may be 70% or less. For example, the haze of the biodegradable polyester film may be 65% or less, 60% or less, 55% or less, 50% or less, 30% to 70% or 30% to 65%.

Method for producing biodegradable polyester film

A method for producing a biodegradable polyester film according to another embodiment includes preparing a prepolymer by esterifying a composition including a diol component and a dicarboxylic acid component including propanediol or a derivative thereof; preparing a polymer by subjecting the prepolymer to a polycondensation reaction; preparing pellets from the polymer; and drying and melt-extruding the pellets, wherein the dicarboxylic acid component includes a first dicarboxylic acid and a second dicarboxylic acid different from the first dicarboxylic acid, The dicarboxylic acid includes at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, and derivatives thereof, and the second dicarboxylic acid includes at least one selected from the group consisting of adipic acid, succinic acid, and derivatives thereof. include

First, a prepolymer is prepared by subjecting a composition including a diol component including propanediol or a derivative thereof and a dicarboxylic acid component to an esterification reaction .

The description of the diol component and the dicarboxylic acid component is the same as described above.

Before the esterification reaction, the titanium-based catalyst or the germanium-based catalyst may be added to the composition. The description of the titanium-based catalyst or the germanium-based catalyst is the same as described above.

In addition, before the esterification reaction, additives such as silica, potassium or magnesium, and at least one selected from the group consisting of stabilizers such as trimethyl phosphate, triphenyl phosphate, trimethyl phosphine, phosphoric acid or phosphorous acid may be additionally added to the composition. can

The esterification reaction may be performed at 250° C. or less for 0.5 to 5 hours. Specifically, the esterification reaction is carried out at 240 ° C. or less, 235 ° C. or less, 180 ° C. to 250 ° C., 185 ° C. to 240 ° C. or 200 ° C. to 240 ° C. At normal pressure until the by-product water and methanol theoretically reach 90% can be performed in For example, the esterification reaction may be performed for 0.5 hours to 4.5 hours, 0.5 hours to 3.5 hours, or 1 hour to 3 hours, but is not limited thereto.

The number average molecular weight of the prepolymer may be 1,500 to 10,000. For example, the number average molecular weight of the prepolymer may be 1,500 to 8,500, 2,000 to 8,000, 3,500 to 6,000, or 4,500 to 5,500. When the number average molecular weight of the prepolymer satisfies the above range, the molecular weight of the polymer can be efficiently increased in the polycondensation reaction, so that mechanical properties such as strength or tear strength can be further improved.

Thereafter, the prepolymer is subjected to a polycondensation reaction to prepare a polymer .

The polycondensation reaction may be performed at 180° C. to 280° C. and 1.0 Torr or less for 1 hour to 5 hours. For example, the polycondensation reaction may be performed at 190°C to 270°C, 210°C to 260°C, or 230°C to 255°C, and 0.9 Torr or less, 0.7 Torr or less, 0.2 Torr to 1.0 Torr, 0.3 Torr to 0.9 Torr or 0.4 Torr to 0.6 Torr, and may be carried out for 1.5 hours to 4.5 hours, 2 hours to 4 hours, or 2.5 hours to 3.5 hours.

In addition, additives such as silica, potassium or magnesium, trimethyl phosphate, triphenyl phosphate, trimethyl phosphine, phosphoric acid or phosphorous acid, and antimony trioxide, antimony trioxide or tetrabutyl to the prepolymer before the polycondensation reaction. At least one selected from the group consisting of a polymerization catalyst such as titanate may be additionally added.

The number average molecular weight of the polymer may be 40,000 or more. For example, the number average molecular weight of the polymer may be 43,000 or more, 45,000 or more, or 50,000 to 70,000. When the number average molecular weight of the polymer satisfies the above range, strength and processability can be further improved.

Thereafter, pellets are prepared from the polymer .

Specifically, after cooling the polymer to 15 ° C. or less, 10 ° C. or less, or 6 ° C. or less, the cooled polymer may be cut to prepare pellets.

The cutting step may be performed without limitation as long as it is a pellet cutter used in the art, and the pellets may have various shapes.

Finally, the pellets are dried and melt extruded .

Specifically, the pellet is dried and melt-extruded to prepare a biodegradable polyester film.

The drying may be performed at 60° C. to 100° C. for 2 hours to 12 hours. Specifically, the drying may be performed at 65° C. to 95° C., 70° C. to 90° C., or 75° C. to 85° C. for 3 hours to 12 hours or 4 hours to 10 hours. By satisfying the drying process conditions of the pellets in the above range, it is possible to further improve the quality of the biodegradable polyester film produced.

The melt extrusion may be performed at a temperature of 270° C. or less and a pressure of 5 torr or less. For example, the melt extrusion may be performed at a temperature of 265 °C or less, 260 °C or less, 255 °C or less, 220 °C to 270 °C or 230 °C to 265 °C and 4.5 torr or less or 4 torr or less. The melt extrusion may be performed by a blown film process, but is not limited thereto.

The above will be described in more detail with reference to the following examples. However, the following examples are only for illustrating the present invention, and the scope of the examples is not limited thereto.

<Example>

Preparation of biodegradable polyester film

Example 1

In a mixture A of 0.6 mol of 1,3-propanediol, 0.7 mol of 1,4-butanediol, 0.5 mol of adipic acid and 0.5 mol of dimethyl terephthalate, tetrabutyl titanate as a titanium-based catalyst (manufacturer: CAMEO Chemicals) 600 ppm After adding , an esterification reaction was performed at 230° C. and atmospheric pressure to prepare a prepolymer having a number average molecular weight of 5,000.

100 ppm of tetrabutyl titanate (manufacturer: CAMEO Chemicals), which is a polycondensation catalyst, was added to the prepolymer, and the temperature was raised to 220° C., followed by polycondensation reaction at 0.5 torr for 3 hours. A polymer having a number average molecular weight of 70,000 was prepared, and after cooling it to 5 ℃, it was cut with a pellet cutter to prepare pellets.

After drying the pellets at 80 ° C. for 5 hours, melt extrusion at 240 ° C. using a blown film extruder (Blown Film Extrusion Line, manufacturer: Eugene Engineering) to prepare a biodegradable polyester film having a thickness of 20 μm did

Example 2

A polymer having a number average molecular weight of 50,000 was prepared by using a mixture B of 0.8 moles of 1,3-propanediol, 0.4 moles of 1,4-butanediol, 0.3 moles of succinic acid, and 0.5 moles of dimethyl terephthalate instead of the mixture A. A biodegradable polyester film was prepared in the same manner as in Example 1, except for the above.

Example 3

Biobased 1,3-propanediol (Susterra ^TM , manufacturer: Dupont) 1.3 moles, adipic acid 0.5 moles and terephthalic acid 0.5 moles in a mixture C of a mixture C, a titanium-based catalyst, a titanium-based catalyst tetrabutyl titanate (Manufacturer: CAMEO Chemicals) 400 ppm was added, and an esterification reaction was performed at 235° C. and atmospheric pressure to prepare a prepolymer having a number average molecular weight of 3,000.

100 ppm of tetrabutyl titanate (manufacturer: CAMEO Chemicals), which is a polycondensation catalyst, was added to the prepolymer, and the temperature was raised to 240 ° C., followed by polycondensation reaction at 0.5 torr for 3 hours to produce a number average molecular weight of 50,000 and after cooling to 5° C., it was cut with a pellet cutter to prepare pellets.

After drying the pellets at 80 ° C. for 5 hours, melt extrusion at 240 ° C. using a blown film extruder (Blown Film Extrusion Line, manufacturer: Eugene Engineering) to prepare a biodegradable polyester film having a thickness of 20 μm did

Comparative Example 1

A polymer having a number average molecular weight of 20,000 was prepared by using a mixture D of 0.7 moles of 1,4-butanediol, 0.5 moles of adipic acid, and 0.5 moles of dimethyl terephthalate in place of the mixture C. In the same manner as in Example 3, a biodegradable film was prepared.

Comparative Example 2

PBAT (Ecoflex, manufacturer: Basf) and PLA (4032D, manufacturer: NatureWork) were mixed at 80:20 and compounded at 220° C. using twin screws to prepare a polymer. The polymer was melt-extruded at 220° C. using a blown film extruder (Blown Film Extrusion Line, manufactured by Eugene Engineering) to prepare a biodegradable polyester film having a thickness of 20 μm.

Comparative Example 3

PLA (4032D, manufacturer: NatureWork) 70% by weight and calcium carbonate 30% by weight were mixed, and compounded at 230°C using twin screws to prepare a polymer. The polymer was melt-extruded at 220° C. using a blown film extruder (Blown Film Extrusion Line, manufactured by Eugene Engineering) to prepare a biodegradable polyester film having a thickness of 20 μm.

<Evaluation example>

Evaluation Example 1: Pinhole Resistance

The film was rotated and reciprocated 2700 times (about 60 minutes) at a rotation angle of 420° at room temperature using a Gelbo Flex manufactured by Gelbo, USA. Then, the film was laid flat on a white paper, oil-based ink was applied on the film using a doctor blade, and the ink dots appearing on the white paper when the film was removed were counted to be the number of pinholes. At this time, the average value obtained by repeating each sample three times was evaluated.

Evaluation Example 2: Unit shock absorption energy

It was measured using a film impact tester (Film Impact Tester) manufactured by Toyoseiki in accordance with the provisions of ASTM D3420. The pendulum tip used a hemispherical shape having a diameter of 1 inch, and the sample film was mounted on a sample stand having a circular hole with a diameter of about 50 mm. The shock absorption energy (kgf-cm) measured in this way was divided by the thickness (㎛) of the sample film to obtain a unit shock absorption energy (kgf-cm/㎛). At this time, the average value obtained by measuring 10 times for each sample was evaluated.

Evaluation Example 3: Puncture Resistance

Measurements were made using UTM (Shimadzu AGS-500D, compression mode) according to ASTM D882. For the tip, a cylindrical shape having a diameter of 1 mm was used, and the compression speed was set to 50 mm/min to measure the puncture resistance (kgf). At this time, the average value obtained by measuring 10 times for each sample was evaluated.

Evaluation Example 4: Storage modulus (E') and storage modulus change (ΔE')

Storage modulus and changes in storage modulus were measured using TA Instrument DMA SS6100 (manufacturer: Seiko) as a dynamic mechanical analyzer. Specifically, the average value (A) of the storage modulus of the film in the temperature range of -20°C to 5°C is calculated as the storage modulus (E') at a frequency of 1Hz and a temperature increase rate of 10°C/min in a stress mode and the absolute value of the difference between the maximum and minimum values of the storage modulus measured at -20°C to 20°C was calculated as the amount of change (ΔE′) of the storage modulus.

Evaluation Example 5: Biodegradability

The biodegradability was measured by measuring the amount of carbon dioxide generated according to KS M3100-1. Specifically, an inoculum container with only compost manufactured in a compost factory was prepared, and a test container in which a film of 5 wt% of the dry weight of the compost was added to the compost was prepared. Thereafter, incubated for 180 days at a temperature of 58±2° C., a moisture content of 50%, and an oxygen concentration of 6% or more, the carbon dioxide generated in each container is collected, and the amount of carbon dioxide generated in each container is measured by titrating it with an aqueous phenolphthalein solution. did. The biodegradation degree was calculated according to Equation 1 below with the measured amount of carbon dioxide generated.

[Equation 1]

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Pinhole resistance (pcs) 8 3 2 20 50 not measurable Unit shock absorption energy (kgf-cm/㎛) 1.5 1.7 1.8 0.8 0.6 0.2 Puncture resistance (kgf) 0.9 1.0 1.1 0.4 0.3 0.1 storage modulus
(Pa) A 3.4 x 10 ⁹ 2.0 x 10 ⁹ 1.0 x 10 ⁹ 4.5 x 10 ⁹ 4.0 x 10 ⁹ 5.0 x 10 ⁹ △E' 0.3 x 10 ⁹ 0.1 x 10 ⁹ 0.05 x 10 ⁹ 0.8 x 10 ⁹ 1.0 x 10 ⁹ 3.0 x 10 ⁹ Biodegradability (%) 90 90 90 90 90 90

As shown in Table 1, the biodegradable polyester films of Examples 1 to 3 exhibited biodegradability, pinhole resistance, unit shock absorption energy, puncture resistance, and storage modulus all compared to the biodegradable films of Comparative Examples 1 to 3 It showed excellent results. In particular, Comparative Example 3 could not be evaluated because the film was torn when evaluating pinhole resistance.

Specifically, it can be seen that the biodegradable polyester films of Examples 1 to 3 are excellent in pinhole resistance, unit shock absorption energy and puncture resistance, and thus have excellent strength and durability, particularly impact resistance. In addition, since the storage modulus is excellent, it can be seen that it is easy to apply as a packaging material for products in various fields, especially products stored and transported at low temperatures.

In particular, the biodegradable films of Examples 1 to 3 were excellent in pinhole resistance, unit impact absorption energy, and puncture resistance compared to the biodegradable film of Comparative Example 1 including a diol component made of only 1,4-butanediol. Comparative Example 1 uses 1,4-butanediol, which has lower structural elongation and elastic recovery compared to the 1,3-propanediol used in Examples 1 to 3, and thus has impact resistance compared to the biodegradable polyester films of Examples 1 to 3 this was low

Claims (10)

A prepolymer is prepared by esterifying a biodegradable polyester resin composition containing a diol component and a dicarboxylic acid component containing 1,3-propanediol or a derivative thereof at 250° C. or lower for 0.5 to 5 hours. step;
preparing a polymer by subjecting the prepolymer to a polycondensation reaction at 180° C. to 280° C. and 1.0 Torr or less for 1 hour to 5 hours;
preparing pellets from the polymer; and
Drying the pellets, and melt-extruding using a blown film extruder;
The diol component comprises a second diol different from the first diol comprising 1,3-propanediol or a derivative thereof;
The second diol comprises at least one selected from the group consisting of butanediol, hexanediol and ethylene glycol,
the dicarboxylic acid component comprises a first dicarboxylic acid and a second dicarboxylic acid different from the first dicarboxylic acid;
The first dicarboxylic acid includes at least one selected from the group consisting of terephthalic acid, dimethyl terephthalate, and derivatives thereof,
The second dicarboxylic acid includes at least one selected from the group consisting of adipic acid, succinic acid, and derivatives thereof,
The molar ratio of the first dicarboxylic acid: the second dicarboxylic acid is 0.8 to 1.9: 1, a method for producing a biodegradable polyester film. delete The method of claim 1,
The molar ratio of the first diol: the second diol is 0.5 to 3: 1, a method for producing a biodegradable polyester film. The method of claim 1,
The molar ratio of the diol component: the dicarboxylic acid component is 1 to 2: 1, a method for producing a biodegradable polyester film. delete The method of claim 1,
The thickness of the biodegradable polyester film is 5 μm to 200 μm, and the unit impact absorption energy is 1.0 kgf-cm / μm or more, the method for producing a biodegradable polyester film. The method of claim 1,
The number of pinholes after the pinhole resistance test of the biodegradable polyester film is 15 or less, and the puncture strength is 0.5 kgf or more, a method for producing a biodegradable polyester film. delete The method of claim 1,
The number average molecular weight of the prepolymer is 1,500 to 10,000,
A method for producing a biodegradable polyester film, wherein the number average molecular weight of the polymer is 40,000 or more. The method of claim 1,
The drying is carried out at 60 ° C. to 100 ° C. for 2 hours to 12 hours,
The method for producing a biodegradable polyester film, wherein the melt extrusion is performed at 270 ℃ or less.