WO2022085845A1 - Naturally derived biodegradable resin composition having improved mechanical properties, formability and weather resistance and method for preparing same - Google Patents

Abstract

The present invention relates to: a naturally derived biodegradable resin composition which is eco-friendly, and not only exhibits excellent biodegradability, but also has improved mechanical properties, formability and weather resistance; and a method for preparing same. More particularly, the naturally derived biodegradable resin composition consists of a first biodegradable aliphatic/aromatic copolyester, a second biodegradable aliphatic/aromatic copolyester, and a chain extender, and the naturally derived biodegradable resin composition is prepared through: a first raw material preparation step of preparing a first biodegradable aliphatic/aromatic copolyester; a second raw material preparation step of preparing a second biodegradable aliphatic/aromatic copolyester; a chain extension reaction step of mixing the first biodegradable aliphatic/aromatic copolyester prepared through the first raw material preparation step, the second biodegradable aliphatic/aromatic copolyester prepared through the second raw material preparation step, and a chain extender, to cause a chain extension reaction; and a solid-state polymerization step of subjecting, to solid-state polymerization, a reaction product that has been chain-extended through the chain extension reaction step.

Description

Naturally-derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance and method for manufacturing the same

The present invention relates to a naturally-derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance, and a method for manufacturing the same. More particularly, it relates to a naturally-derived biodegradable resin composition that is environmentally friendly, exhibits excellent biodegradability, and has excellent mechanical properties, moldability and weather resistance, and a method for manufacturing the same.

Social problems are emerging around the world about environmental pollution, and in the case of various plastics used in existing industries, they are difficult to decompose naturally and are often disposed of by landfill and incineration after use. In this case, there is a problem of causing environmental pollution due to the lack of landfill sites and harmful substances generated during incineration. As a solution to these problems, research on biodegradable resins is being actively conducted.

There are several types of biodegradable resins known so far, but they have different biodegradable properties, molecular weights, and various physical properties.

Polybutylene succinate (PBS) or poly(butylene adipate-co-butylene terephthalate (PBAT), an aliphatic polyester currently in the spotlight for biodegradable films worldwide, has properties similar to polyethylene and polypropylene. Therefore, it is expected as an alternative resource for synthetic resins.

However, since the biodegradable resin composition is composed only of materials obtained from fossil raw materials, environmental friendliness such as resource depletion and global warming is poor.

In an effort to solve the above problems, research on converting raw materials used in biodegradable resin compositions to natural ones is being actively conducted.

For example, an aliphatic dicarboxylic acid obtained through fermentation of polysaccharides synthesized by photosynthesis of plants such as glucose, cellulose, and glucose derived from nature is used as a raw material for biodegradable aliphatic (or aliphatic / aromatic) polyester or is newly tried. . However, the aliphatic dicarboxylic acid obtained in this process needs to be extracted, neutralized, and purified according to the intended use in order to be used in polyester production due to impurities such as nitrogen, ammonia, and metal cations generated from the fermentation process.

Methods for producing polyester using a naturally occurring dicarboxylic acid obtained through the above method are described in various literatures (Muer Materials, Vol. 1, No. 11, page 31 (2001); Japanese Patent Laid-Open No. 2005-27533; Biotechnology and Bioengineering Symp). No. 17 (1986) 355-363; Journal of the American Chemical Society No. 116 (1994) 399-400; Appl. Microbiol Biotechnol No. 51 (1999) 545-552; Japanese Patent Application Laid-Open No. 2005-139287) has been However, dicarboxylic acid derived from biomass resources that has undergone the purification process contains nitrogen element or ammonia used in the refining process, nitrogen element contained therein, organic acids, inorganic acids, and metal cations, compared to dicarboxylic acids derived from fossil resources. Therefore, it is difficult to obtain sufficient molecular weight due to poor reactivity, so it is difficult to obtain a sufficient molecular weight, resulting in poor molding processability and difficult to obtain sufficient mechanical properties. .

As one method for solving the above problems, as a first copolymerization component in Korea Patent Registration No. 10-1276100 (published on June 12, 2013) (a) aromatic dicarboxylic acid, its acid anhydride, or a mixture thereof and (b) a dicarboxylic acid component comprising an aliphatic dicarboxylic acid including glutaric acid, an acid anhydride thereof, or a mixture thereof; and a glycol component consisting of naturally-derived ethylene glycol, isosorbide and neopentyl glycol as a second copolymerization component, wherein the dicarboxylic acid component is the aromatic dicarboxylic acid, its acid anhydride, or a mixture thereof (a ) is 60 to 95 mol%, the aliphatic dicarboxylic acid containing glutaric acid, its acid anhydride, or a mixture (b) thereof is 5 to 40 mol%, and the glycol component is the naturally derived ethylene glycol A biodegradable copolyester resin made from a natural raw material is known, characterized in that 80 to 99.8 mol%, the isosorbide is 0.1 to 10 mol%, and the neopentyl glycol is 0.1 to 10 mol%.

In addition, Korean Patent Registration No. 10-1502051 (announced on March 06, 2015) discloses a dicarboxylic acid component comprising an aromatic dicarboxylic acid and a petroleum or naturally-derived aliphatic dicarboxylic acid; and petroleum or naturally-derived 1,4-butanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, and an aliphatic glycol component selected from the group consisting of polyols. The biomass-derived aliphatic dicarboxylic acid is included in an amount of more than 15 to 30 mol% based on 100 mol% of the total dicarboxylic acid component, and the petroleum-based or biomass-derived polyol is based on 100 mol% of the total aliphatic glycol component. A biodegradable copolyester resin is known, which is contained in 10-30 mol%, has a hardness (Shore D) of 30-50, and an intrinsic viscosity of 1.1-1.6 dL/g.

In addition, in Korea Patent Registration No. 10-1514786 (announced on April 17, 2015), 1 mol% to 30 mol% of naturally-derived 2,5-bishydroxymethylfuran and 2,5-bishydroxymethylfuran other than Consists of a reaction product of a diol component and a dicarboxylic acid component including the remaining amount of an aromatic diol compound and an aliphatic diol compound, wherein the molar ratio of the dicarboxylic acid component to the diol component is 1:1.05 to 1:3.0, and 80°C to 100°C Polyester resins are known, having a glass transition temperature of

However, the biodegradable polyester resins using the above-mentioned naturally-derived raw materials have a low degree of completion of the reaction due to impurities contained in the natural-derived raw materials, and thus hydrolysis occurs more easily compared to polyesters using fossil raw materials, resulting in a problem in durability. do.

One object of the present invention is to provide a naturally-derived biodegradable resin composition that is environmentally friendly, exhibits excellent biodegradability, and has excellent mechanical properties, moldability and weather resistance.

Another object of the present invention is to provide a method for preparing the naturally-derived biodegradable resin composition.

The object of the present invention is not limited to the object mentioned above. The objects of the present invention will become more apparent from the following description, and will be realized by means and combinations thereof described in the claims.

In order to achieve the above object, the present invention has mechanical properties, moldability and weather resistance, characterized in that it consists of a first biodegradable aliphatic/aromatic copolyester, a second biodegradable aliphatic/aromatic copolyester, and a chain extender. It provides an improved naturally-derived biodegradable resin composition.

The first biodegradable aliphatic/aromatic copolyester of the present invention is prepared through esterification and polycondensation of an acid component and an aliphatic diol including a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid. characterized in that

The acid component used for preparing the first biodegradable aliphatic/aromatic copolyester of the present invention is characterized in that it is a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid.

The naturally-derived aliphatic dicarboxylic acid contained in the acid component used in the preparation of the first biodegradable aliphatic/aromatic copolyester of the present invention is a naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and a naturally-derived aliphatic dicarboxylic acid having 10 carbon atoms. It is characterized in that it consists of an acid.

The naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and the naturally-derived aliphatic dicarboxylic acid having 10 carbon atoms of the present invention are mixed in a molar ratio of 75:25 to 25:75.

Aromatic dicarboxylic acid (or an esterified derivative thereof) contained in the acid component used in the production of the first biodegradable aliphatic/aromatic copolyester of the present invention is terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthoic acid and at least one selected from the group consisting of esterified derivatives thereof.

Naturally-derived aliphatic dicarboxylic acid and aromatic dicarboxylic acid used in the preparation of the first biodegradable aliphatic/aromatic copolyester of the present invention are mixed in a molar ratio of 65:35 to 50:50.

The aliphatic diol used in the preparation of the first biodegradable aliphatic/aromatic copolyester of the present invention is composed of at least one selected from the group consisting of C ₂ to C ₁₂ linear aliphatic diol and C ₅ to C ₁₅ cycloaliphatic diol. characterized in that

The acid component and the aliphatic diol included in the first biodegradable aliphatic/aromatic copolyester of the present invention are mixed in a molar ratio of 1:25 to 1:1.5.

The second biodegradable aliphatic/aromatic copolyester of the present invention is prepared through an esterification reaction and a polycondensation reaction of an acid component containing a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and an aliphatic diol characterized in that

The acid component used in the preparation of the second biodegradable aliphatic/aromatic copolyester of the present invention is characterized in that it is a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid.

The naturally-derived aliphatic dicarboxylic acid contained in the acid component used in the preparation of the second biodegradable aliphatic/aromatic copolyester of the present invention is characterized in that it is a naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms.

The aromatic dicarboxylic acid included in the acid component used in the preparation of the second biodegradable aliphatic/aromatic copolyester of the present invention is composed of terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthoic acid, and esterified derivatives thereof. It is characterized in that it consists of one or more selected from the group.

The naturally-derived aliphatic dicarboxylic acid and aromatic dicarboxylic acid used in the preparation of the second biodegradable aliphatic/aromatic copolyester of the present invention are mixed in a molar ratio of 55:45 to 50:50.

The aliphatic diol used in the preparation of the second biodegradable aliphatic/aromatic copolyester of the present invention is composed of at least one selected from the group consisting of C ₂ to C ₁₂ linear aliphatic diol and C ₅ to C ₁₅ cycloaliphatic diol. characterized in that

The acid component and the aliphatic diol included in the second biodegradable aliphatic/aromatic copolyester of the present invention are mixed in a molar ratio of 1: 1.10 to 1: 1.35.

The first biodegradable aliphatic/aromatic copolyester of the present invention and the second biodegradable aliphatic/aromatic copolyester are mixed in a weight ratio of 70: 30 to 10: 90.

The chain extender of the present invention is characterized in that at least one of an isocyanate compound and a carbodiimide compound.

In addition, the biodegradable resin composition with improved mechanical properties, moldability and weather resistance of the present invention may further include a polyfunctional compound represented by Formula 1 below.

[Formula 1]

(In Formula 1, m is an integer of 1 to 30.)

The compound of Formula 1 of the present invention is characterized in that it is prepared by an esterification reaction by mixing DL-Malic acid and hydroquinone.

In addition, the biodegradable resin composition with improved mechanical properties, moldability and weather resistance of the present invention may further contain one or more selected from the group consisting of antioxidants, UV stabilizers and lubricants in addition to the above components.

In order to achieve the above object, the present invention also provides a first raw material manufacturing step for preparing a first biodegradable aliphatic/aromatic copolyester, a second raw material manufacturing step for preparing a second biodegradable aliphatic/aromatic copolyester, Chain extension reaction by mixing the first biodegradable aliphatic/aromatic copolyester prepared through the first raw material manufacturing step, the second biodegradable aliphatic/aromatic copolyester prepared through the second raw material manufacturing step, and a chain extender A method for producing a naturally-derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance, characterized in that it comprises a chain extension reaction step, and a solid-phase polymerization step of solid-state polymerization of a chain-extended reactant through the chain extension reaction step to provide.

The chain extension reaction step of the present invention is characterized in that it proceeds at a temperature of 100 to 180 ℃.

The solid-state polymerization step of the present invention is characterized in that it proceeds at a temperature of 60 to 110 ℃.

The first raw material preparation step and the second raw material preparation step of the present invention are characterized in that it is made in the presence of a polyfunctional compound represented by the following formula (1).

[Formula 1]

(In Formula 1, m is an integer of 1 to 30.)

A biodegradable resin composition having excellent mechanical properties, moldability and weather resistance according to the present invention and a method for manufacturing the same are environmentally friendly, exhibit excellent biodegradability, and provide a biodegradable resin composition having excellent mechanical properties, moldability and weather resistance shows excellent effect.

1 is a flowchart illustrating a method for preparing a biodegradable resin composition having excellent mechanical properties, moldability and weather resistance according to the present invention.

In one aspect, the present invention provides a naturally derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance comprising a first biodegradable aliphatic/aromatic copolyester, a second biodegradable aliphatic/aromatic copolyester, and a chain extender. to provide.

In the present invention, in order to distinguish between the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester for convenience, the first biodegradable aliphatic/aromatic copolyester can be expressed as component A and the second biodegradable aliphatic/aromatic copolyester can be expressed as component B.

In addition, in the present invention, in order to better express the characteristics of the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester, a naturally-derived first biodegradable or second biodegradable aliphatic It can also be expressed as /aromatic copolyester.

The first biodegradable aliphatic/aromatic copolyester comprises an acid component and an aliphatic diol containing a mixed component of a naturally-derived aliphatic dicarboxylic acid having 4 and 10 carbon atoms and an aromatic dicarboxylic acid (or an esterified derivative thereof). It is obtained through an esterification reaction, an esterification exchange reaction, and a polycondensation reaction as a main component.

In addition, the second biodegradable aliphatic/aromatic copolyester is an ester mainly comprising an acid component and an aliphatic diol containing a naturally occurring aliphatic dicarboxylic acid having 4 carbon atoms and an aromatic dicarboxylic acid (or an esterified derivative thereof). It is obtained through an esterification reaction, an esterification exchange reaction, and a polycondensation reaction.

The naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms used for preparing the first biodegradable aliphatic/aromatic copolyester is succinic acid, the naturally-derived aliphatic dicarboxylic acid having 10 carbon atoms is sebacic acid, and the aromatic dicarboxylic acid (or The esterified derivative) may be at least one selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthoic acid, and esterified derivatives thereof. Preferably, the aromatic dicarboxylic acid may be terephthalic acid, isophthalic acid, phthalic acid, or an esterified derivative thereof.

The input ratio of naturally-derived succinic acid and naturally-derived sebacic acid, which are aliphatic dicarboxylic acids used in the production of the first biodegradable aliphatic/aromatic copolyester, is 75: 25 to 25: 75 in a molar ratio.

In the production of the first biodegradable aliphatic/aromatic copolyester, the acid component is a mixed component of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid are 65: 35 to 50: It is a component mixed in a molar ratio of 50, preferably in a molar ratio of 52:48 to 55:45. At this time, if the content of the aromatic dicarboxylic acid is less than 35 moles, the effect of improving mechanical properties including elongation and tear strength cannot be expected, and if the content of the aromatic dicarboxylic acid is more than 50 moles, the biodegradability effect may be lost.

In addition, the naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms used in the production of the second biodegradable aliphatic/aromatic copolyester is succinic acid, and the aromatic dicarboxylic acid (or an esterified derivative thereof) is terephthalic acid, isophthalic acid, phthalic acid , may be at least one selected from the group consisting of 2,6-naphthoic acid and esterified derivatives thereof. Preferably, the aromatic dicarboxylic acid may be terephthalic acid, isophthalic acid, phthalic acid, or an esterified derivative thereof.

In the production of the second biodegradable aliphatic/aromatic copolyester, the acid component is a mixed component of aliphatic dicarboxylic acid and aromatic dicarboxylic acid, and the aliphatic dicarboxylic acid and aromatic dicarboxylic acid are 55: 45 to 50: 50 It is a component mixed in a molar ratio. At this time, if the content of the aromatic dicarboxylic acid is less than 45 mol, the effect of improving mechanical properties including elongation and tear strength cannot be expected, and if it exceeds 50 mol, the biodegradability effect may be lost.

In the production of the first biodegradable aliphatic/aromatic copolyester, the acid component and the aliphatic diol including a mixed component of a naturally derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid are in a molar ratio of 1: 1.25 to 1: 1.5, preferably It can be mixed in a molar ratio of 1: 1.30 to 1: 1.35. At this time, if the molar ratio of the aliphatic dicarboxylic acid to the aliphatic diol is less than 1: 1.25, the esterification reaction or the transesterification reaction may not be smoothly performed, which may adversely affect the color of the obtained resin composition. Conversely, when the molar ratio exceeds 1: 1.5, the production cost increases in terms of cost due to a decrease in the degree of vacuum in the reaction process, thereby reducing economic efficiency.

In addition, in the production of the first biodegradable aliphatic/aromatic copolyester, the acid component and the aliphatic diol including a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid in a molar ratio of 1: 1.10 to 1: 1.35, preferably Preferably, it can be mixed in a molar ratio of 1: 1.2 to 1: 1.30. At this time, if the molar ratio of the aliphatic dicarboxylic acid to the aliphatic diol is less than 1: 1.10, the esterification reaction or the transesterification reaction may not be smoothly performed, which may adversely affect the color of the obtained resin composition. Conversely, when the molar ratio exceeds 1: 1.35, the production cost increases in terms of cost due to a decrease in the degree of vacuum in the reaction process, thereby reducing economic efficiency.

The aliphatic diol used in the preparation of the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester is composed of a C ₂ to C ₁₂ linear aliphatic diol and a C ₅ to C ₁₅ cycloaliphatic diol. At least one selected from the group, preferably, it is characterized in that it consists of at least one selected from the group consisting of C ₂ to C ₆ linear aliphatic diol and C ₅ to C ₆ cycloaliphatic diol.

The first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester have a weight ratio of 70: 30 to 10: 90, preferably 60: 40 to 20: 80, more preferably It is mixed in a weight ratio of 50: 50 to 30: 70. When the content of the first biodegradable aliphatic/aromatic copolyester is less than 10 parts by weight, it is difficult to realize the desired tear strength and impact strength. There are difficulties in product molding.

In the process of preparing the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester, aliphatic dicarboxylic acid and aromatic dicarboxylic acid are essentially present in the presence of a long-chain polyfunctional compound as a reaction accelerator. The reaction rate is improved by mixing an acid component containing a mixed component of carboxylic acid and an aliphatic diol to carry out an esterification reaction, a transesterification reaction, and a polycondensation reaction, thereby improving productivity and economic feasibility, as well as providing superior productivity and economy compared to the prior art. By reducing the polycondensation time of the biodegradable resin produced by preventing an increase in terminal carboxyl groups, it is possible to secure a resin composition with a low acid value. The low terminal carboxyl group concentration in the composition suppresses the hydrolysis rate of the resin composition, thereby slowing the decomposition rate and improving durability.

In addition, the first biodegradable aliphatic/aromatic copolyester obtained after the polycondensation reaction and the second biodegradable aliphatic/aromatic copolyester are mixed in a predetermined ratio, and then a chain extension reaction and a solid-state polymerization reaction are essentially performed, and finally the existing Compared to the biodegradable aliphatic/aromatic biodegradable copolyester resin of It has a friendly advantage.

Specifically, the biodegradable resin composition prepared through the present invention is an acid component comprising a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid in the presence of a polyfunctional compound represented by the following Chemical Formula 1, and an aliphatic diol After mixing the first biodegradable aliphatic/aromatic copolyester obtained through esterification reaction, transesterification reaction, and polycondensation reaction and the second biodegradable aliphatic/aromatic copolyester, a twin screw extruder or a kneader is used to chain It is prepared by sequentially reacting an extension reaction and a solid-state polymerization reaction.

[Formula 1]

(In Formula 1, m is an integer of 1 to 30.)

The polyfunctional compound may be a reaction accelerator that is added to the esterification reaction when the biodegradable resin composition is prepared. The polyfunctional compound acts as a reaction accelerator in the esterification synthesis process of the biodegradable resin, and as compared to the conventional aliphatic/aromatic copolyester resin, a biodegradable resin composition having a desired number average molecular weight and weight average molecular weight can be obtained easily and quickly. The improvement of the reaction rate has an economic advantage due to high productivity.

In addition, the biodegradable aliphatic/aromatic copolyester resin prepared from the present invention can be prepared by shortening the high-temperature polycondensation reaction time due to the use of the polyfunctional compound due to the low concentration of terminal carboxyl groups in the prior art biodegradable aliphatic/aromatic copolyester It has a low acid value and has excellent durability due to its effect.

In addition, the polyfunctional compound has the advantage of easy handling and reaction control due to different reaction activities due to steric hindrance in the molecular structure and functional groups at different positions. That is, by using the polyfunctional compound as a reaction accelerator, the reaction rate is improved, and the reaction control of polyfunctional compounds such as citric acid and glycerol used as conventional reaction accelerators is difficult and gelation easily occurs. can do. In addition, in the case of citric acid and glycerol, which are used as conventional reaction accelerators, the reactivity is so high that it is difficult to control, and the active reaction site of the product after the polycondensation reaction is small because it is easily combined with the reaction site of the reactant, whereas in the present invention In the case of the polyfunctional compound used, the concentration of the remaining active reaction site is relatively high, so the efficiency of the chain extension reaction and the solid-state polymerization reaction sequentially performed after the polycondensation reaction which is essential in the present invention is high, so that an aliphatic having a desired molecular weight /aromatic copolyesters can be obtained.

In addition, by forming side chains in the molecular structure of the main chain of the biodegradable resin, not only the tear strength is improved, but also the molecular weight distribution is widened, thereby providing excellent processability to the biodegradable resin composition.

The polyfunctional compound includes DL-Malic acid and hydroquinone in a molar ratio of 1: 1 to 1: 1.5, preferably 1: 1 to 1: 1.5, more preferably 1: 1.15 to 1: It can be obtained by esterification by mixing in a molar ratio of 1.3, most preferably 1:1.2 in molar ratio. In this case, when the molar ratio of DL-malic acid to hydroquinone is out of the range, the polyfunctional compound represented by Formula 1 may not be properly synthesized.

The polyfunctional compound may be prepared by Scheme 1 below. Preferably, the polyfunctional compound may be obtained by an esterification reaction by mixing DL-Malic acid and hydroquinone.

[Scheme 1]

(In Scheme 1, m = an integer of 1 to 30.)

The polyfunctional compound may be mixed in an amount of 0.1 to 3 g, preferably 0.8 to 2.5 g, more preferably 1 to 2 g, and most preferably 1 to 1.5 g, per mole of the acid component. At this time, if the mixing amount of the polyfunctional compound is less than 0.1 g per 1 mol of the acid component, the esterification reaction of the acid component and the fatty acid diol does not sufficiently occur and the reaction rate may be slowed. Conversely, if it exceeds 3 g, the overall reaction rate may be increased, It induces gelation of the obtained resin to generate a gel or a fish eye in a product manufactured using the resin, or in severe cases, it is impossible to discharge the resin from the reactor.

In another aspect, the present invention provides a first raw material production step (S101) for producing a first biodegradable aliphatic/aromatic copolyester, a second raw material production step for producing a second biodegradable aliphatic/aromatic copolyester ( S101-1), the first biodegradable aliphatic/aromatic copolyester prepared through the first raw material manufacturing step (S101) and the second biodegradable aliphatic/ prepared through the second raw material manufacturing step (S101-1) A chain extension reaction step (S103) of mixing the aromatic copolyester and a chain extender to a chain extension reaction, and a solid-state polymerization step (S105) of solid-state polymerization of the chain-extended reactant through the chain extension reaction step (S103) Provided is a method for preparing a naturally-derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance.

A polyfunctional compound is used in the first raw material manufacturing step (S101) and the second raw material manufacturing step (S101-1), and the manufacturing process of the polyfunctional compound will be described below.

The preparation of the polyfunctional compound consists of a process of preparing a polyfunctional compound represented by the following Chemical Formula 1 by esterification of DL-malic acid and hydroquinone.

[Formula 1]

(In Formula 1, m is an integer of 1 to 30.)

In addition, the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester prepared through the first raw material manufacturing step (S101) and the second raw material manufacturing step (S101-1) are the above It is made by performing an esterification reaction, a transesterification reaction, and a polycondensation reaction of an acid component including a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and an aliphatic diol in the presence of a polyfunctional compound of

The chain extension reaction step (S103) includes the first biodegradable aliphatic/aromatic copolyester prepared through the first raw material manufacturing step (S101) and the second prepared through the second raw material manufacturing step (S101-1). In a chain extension reaction by mixing biodegradable aliphatic/aromatic copolyester and chain extender, the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester are placed in a twin-screw extruder or a kneader. After the addition, 0.05 to 1 part by weight of one compound selected from an isocyanate compound or a carbodiimide compound is added as a chain extender, and the process is performed at a temperature of 100 to 180°C.

The solid-state polymerization step (S105) is a step of solid-state polymerization of the chain-extended reactant through the chain extension reaction step (S103). It consists of a process of preparing a biodegradable resin composition by solid-state polymerization at a temperature of 110 °C.

Hereinafter, a method for preparing the biodegradable resin composition will be described in more detail.

Specifically, the preparation of the polyfunctional compound is a step of preparing the polyfunctional compound represented by Formula 1 by esterifying DL-malic acid and hydroquinone. Preferably, in the presence of a catalyst, DL-malic acid and hydroquinone in a molar ratio of 1: 1 to 1: 1.5 are esterified at a temperature of 195 to 220 ° C. for 180 to 240 minutes to prepare a polyfunctional compound represented by Formula 1 is made in the process of

In the above process, the esterification reaction may be performed by adding the DL-malic acid and hydroquinone to a reactor equipped with a reflux tower, and then slowly raising the temperature while stirring. In this case, the final temperature rise temperature and reaction time during the esterification reaction is 180 to 240 minutes at 195 to 220 ° C., preferably 190 to 230 minutes at 200 to 215 ° C., more preferably 200 to 220 minutes at 205 to 215 ° C. can be done while If the final temperature rise temperature is less than 195° C. or the reaction time is less than 180 minutes, the esterification reaction may not proceed smoothly. Conversely, if the final temperature rise temperature exceeds 220° C. or the reaction time exceeds 240 minutes, a good quality polyfunctional compound cannot be obtained due to thermal decomposition of the obtained product.

In this case, the catalyst used may be at least one selected from the group consisting of monobutyltin oxide, titanium propoxide and tetrabutyl titanate, but is not limited thereto. The catalyst is 0.01 to 0.2 g, more preferably 0.01 to 0.05 g per 1 mole of DL-malic acid, and then, while maintaining the temperature of the reactor at 195 to 220° C., completely draining the theoretical amount of water to obtain a polyfunctional compound can do.

In the first raw material manufacturing step (S101), an acid component including a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid in the presence of the polyfunctional compound, and an aliphatic diol esterification reaction, transesterification reaction and preparing a naturally-derived first biodegradable aliphatic/aromatic copolyester as a reaction product through a polycondensation reaction.

More specifically, in the first raw material manufacturing step (S101), in the presence of the polyfunctional compound, an acid component and an aliphatic diol containing a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid are mixed with 1:1.25 to First biodegradable aliphatic/aromatic copolyester derived from nature by mixing in a molar ratio of 1: 1.5, preparing an oligomer through esterification and transesterification at a temperature of 185 to 235° C., and then carrying out a polycondensation reaction of the obtained compound It consists of the process of manufacturing a product.

In this case, the acid component is a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, and the naturally-derived aliphatic dicarboxylic acid and the aromatic dicarboxylic acid have a molar ratio of 65: 35 to 50: 50, preferably 52 : 48 to 55: a component mixed in a molar ratio of 45. At this time, if the content of the aromatic dicarboxylic acid is less than 35 moles, the effect of improving mechanical properties including elongation and tear strength cannot be expected, and if the content of the aromatic dicarboxylic acid is more than 50 moles, the biodegradability effect may be lost.

In addition, specific examples of the aromatic dicarboxylic acid may be at least one selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthoic acid, and esterified derivatives thereof. Preferably, the aromatic dicarboxylic acid may be terephthalic acid, isophthalic acid, phthalic acid, or an esterified derivative thereof, and more preferably terephthalic acid or dimethyl terephthalate, which is an esterified derivative thereof.

In addition, the aliphatic dicarboxylic acid is a mixed component of naturally-derived succinic acid and naturally-derived sebacic acid, and the input ratio is 75: 25 to 25: 75 in a molar ratio.

If the molar ratio of sebacic acid among the aliphatic acid components is less than 25 moles, sufficient elongation, tear strength, and biodegradability of the resin may be lowered. It is disadvantageous in terms of blocking properties, mold release properties and shrinkage of the molded product.

In addition, the reaction temperature in the esterification reaction proceeding in the first raw material manufacturing step (S101) is preferably 185 to 235 ℃, more preferably 190 to 200 ℃, it is good to be carried out at 195 ℃ most preferably. If the temperature is less than 185°C, the esterification reaction and transesterification reaction may not sufficiently occur, and conversely, if the temperature is higher than 235°C, the resulting oligomer may be thermally decomposed.

In addition, the aliphatic diol may be a C ₂ to C ₁₂ linear aliphatic diol, a C ₅ to C ₁₅ cycloaliphatic diol, or a mixture thereof. Preferably, it may be a C ₂ to C ₆ linear aliphatic diol, a C ₅ to C ₆ cycloaliphatic diol, or a mixture thereof. More preferably, the aliphatic diol is ethylene glycol, 1,2-propanediol, 1.2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol and 1,2-cyclohexanedimethanol, 1 It may be at least one selected from the group consisting of ,4-cyclohexanedimethanol. Even more preferably, 1,4-butanediol, ethylene glycol, or a mixture thereof may be used as the aliphatic diol.

The acid component and the aliphatic diol may be mixed in a molar ratio of 1: 1.25 to 1: 1.5, preferably 1: 1.30 to 1: 1.35. At this time, if the molar ratio of the aliphatic dicarboxylic acid to the aliphatic diol is less than 1: 1.25, the esterification reaction or the transesterification reaction may not be smoothly performed, which may adversely affect the color of the obtained resin composition. Conversely, when the molar ratio exceeds 1: 1.5, the production cost increases in terms of cost due to a decrease in the degree of vacuum in the reaction process, thereby reducing economic efficiency.

The second raw material manufacturing step (S101-1) is an esterification reaction of an acid component including a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid in the presence of the polyfunctional compound, and an aliphatic diol, an ester This is a step of preparing a first naturally-derived biodegradable aliphatic/aromatic copolyester as a reaction product through an exchange reaction and a polycondensation reaction.

More specifically, in the second raw material manufacturing step (S101-1), an acid component including a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, and an aliphatic diol in the presence of the polyfunctional compound : 1.10 to 1: 1.35 in a molar ratio to prepare an oligomer through esterification and transesterification at 185 to 215° C., and then carry out a polycondensation reaction of the obtained compound to conduct a naturally-derived second biodegradable aliphatic/aromatic copoly This is the step of preparing the ester.

In this case, the acid component is a mixed component of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, and the naturally-derived aliphatic dicarboxylic acid and the aromatic dicarboxylic acid have a molar ratio of 55: 45 to 50: 50, preferably 58 : 42 to 55: 45 is a component mixed in a molar ratio.

If the content of the aromatic dicarboxylic acid is less than 45 moles, the effect of lowering processability due to a slow cooling rate and improving mechanical properties including elongation and tear strength cannot be expected, and if the content of the aromatic dicarboxylic acid is more than 50 moles, the biodegradability effect may be lost. .

In addition, specific examples of the aromatic dicarboxylic acid may be at least one selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthoic acid, and esterified derivatives thereof. Preferably, the aromatic dicarboxylic acid may be terephthalic acid, isophthalic acid, phthalic acid, or an esterified derivative thereof, and more preferably terephthalic acid or dimethyl terephthalate, which is an esterified derivative thereof.

In addition, the reaction temperature in the esterification reaction proceeding in the second raw material manufacturing step (S101-1) is preferably 185 to 215 °C, more preferably 190 to 210 °C, most preferably 195 to 200 °C. good to do If the temperature is less than 185 ° C, the esterification reaction and transesterification reaction may not sufficiently occur. Conversely, when the temperature exceeds 215 ° C., the resulting oligomer is thermally decomposed or tetrahydrofuran is generated, thereby affecting the color and reactivity of the reactant. can give

In addition, the aliphatic diol may be a C ₂ to C ₁₂ linear aliphatic diol, a C ₅ to C ₁₅ cycloaliphatic diol, or a mixture thereof. Preferably, it may be a C ₂ to C ₆ linear aliphatic diol, a C ₅ to C ₆ cycloaliphatic diol, or a mixture thereof. More preferably, the aliphatic diol is ethylene glycol, 1,2-propanediol, 1.2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol and 1,2-cyclohexanedimethanol, 1 It may be at least one selected from the group consisting of ,4-cyclohexanedimethanol. Even more preferably, 1,4-butanediol, ethylene glycol, or a mixture thereof may be used as the aliphatic diol.

The acid component and the aliphatic diol may be mixed in a molar ratio of 1: 1.10 to 1: 1.35, preferably 1: 1.2 to 1: 1.30. At this time, if the molar ratio of the aliphatic dicarboxylic acid to the aliphatic diol is less than 1: 1.10, the esterification reaction or the transesterification reaction may not be smoothly performed, which may adversely affect the color of the obtained resin composition. Conversely, when the molar ratio exceeds 1: 1.35, the production cost increases in terms of cost due to a decrease in the degree of vacuum in the reaction process, thereby reducing economic efficiency.

In the esterification reaction and transesterification reaction of the first raw material production step (S101) and the second raw material production step (S101-1), a mixed component of the naturally-derived aliphatic dicarboxylic acid and aromatic dicarboxylic acid is When different by-products are generated in the reaction with an aliphatic diol, the two reactions may be divided into stages to proceed with the reaction. For example, when succinic acid is used as the naturally-derived aliphatic dicarboxylic acid and dimethyl terephthalate is used as the aromatic dicarboxylic acid, the succinic acid reacts with the aliphatic glycol and water flows out as a by-product of the reaction, and dimethyl terephthalate is an aliphatic glycol It may react with methanol to generate methanol as a by-product of the reaction. In this case, when the two components are reacted together with an acid component, a phenomenon in which the reactor column is clogged due to competition between the two reactions may not occur.

Accordingly, when the mixed component of the naturally-derived aliphatic dicarboxylic acid and the aromatic dicarboxylic acid is used, it may be dividedly added within the range of use of the total amount or may be added at a time in one selected reaction step. Preferably, it is good to divide the reaction into two steps. For example, after adding succinic acid and an aliphatic diol, a theoretical amount of water is drained, and dimethyl terephthalate is added in the presence of an esterification reaction product of succinic acid and an aliphatic diol to proceed with the esterification reaction, and the theoretical amount of methanol is drained for the reaction. may be completed or the reaction may be carried out in the reverse order. In this case, the total amount of the aliphatic diol to be added may be added in the first step or divided according to the molar ratio in each step.

At the initial stage or the end of the reaction of the esterification reaction and the transesterification reaction, a catalyst may be further included, and the catalyst is specifically titanium isopropoxide, calcium acetate, antimony trioxide, dibutyltin oxide, and antimony acetate. , tetrabutyl titanate and tetrapropyl titanate may be used at least one selected from the group consisting of, but is not limited thereto.

The catalyst may be mixed in an amount of 0.01 to 0.5 g, more preferably 0.03 to 0.2 g, and most preferably 0.1 g per 1 mole of the acid component. At this time, if the content of the catalyst is less than 0.01 g, the reaction rate of the esterification reaction and the transesterification reaction may be delayed or may not react sufficiently. Conversely, if the content of the catalyst is more than 0.5 g, side reactions may occur or the reverse reaction rate may increase, thereby causing color change and deterioration of physical properties of the reactants.

In addition, a stabilizer may be further included at the initial stage or at the end of the esterification reaction and the transesterification reaction. The stabilizer may include at least one selected from the group consisting of trimethyl phosphate, phosphoric acid and triphenyl phosphate, but is not limited thereto.

The stabilizer may be mixed in an amount of 0.01 to 0.5 g, more preferably 0.03 to 0.2 g, and most preferably 0.1 g per 1 mole of the acid component. When the content of the stabilizer is less than 0.01 g, the esterification reaction and the transesterification reaction may not react sufficiently, and on the contrary, if it exceeds 0.5 g, the reaction rate is slowed by hindering the reaction progress and the biodegradable resin having a sufficient amount of high molecular weight The composition cannot be obtained.

The reaction products of the esterification reaction and the esterification exchange reaction may be subjected to polycondensation to prepare a first biodegradable aliphatic/aromatic copolyester and a second biodegradable aliphatic/aromatic copolyester.

Preferably, the reaction product prepared above is prepared by polycondensation reaction at 235 to 255° C. under a vacuum degree of 0.1 to 2 torr for 100 to 240 minutes, wherein the polycondensation temperature and pressure are 2 torr or less at 235 to 255° C. , preferably at 240 to 245 ℃ 0.1 to 2 torr, most preferably at 245 ℃ 1 to 1.5 torr conditions.

If both the polycondensation temperature and vacuum conditions are not satisfied, the polycondensation reaction is not performed properly, or the resulting product is decomposed by high temperature and oxidation to obtain a poor color of the biodegradable resin composition or a resin having a desired molecular weight Can not.

The first biodegradable aliphatic/aromatic copolyester produced through the first raw material manufacturing step (S101) has a number average molecular weight of 15,000 to 30,000, and a melt flow index of 190°C and 2,160 g under measurement conditions of 30 g/10 min to 50 g/10 min, and an acid value of 1.0 mgKOH/g to 1.5 mgKOH/g.

In addition, the second biodegradable aliphatic/aromatic copolyester produced through the second raw material manufacturing step (S101-1) has a number average molecular weight of 15,000 to 30,000, and a melt flow index of 190°C and 2,160 g. Under 25g/10min to 50g/10min, the acid value is 0.5mgKOH/g to 1.5mgKOH/g.

The chain extension reaction step (S103) includes the first biodegradable aliphatic/aromatic copolyester prepared through the first raw material manufacturing step (S101) and the second prepared through the second raw material manufacturing step (S101-1). This is a chain extension reaction by mixing biodegradable aliphatic/aromatic copolyester and a chain extender.

More specifically, after mixing the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester, it is added to a twin-screw extruder or a kneader, and 0.05 to 1 part by weight of a chain extender is added It is a step of chain extension reaction in the range of 100 to 180 ℃.

In the case of the reactant obtained in the chain extension reaction step (S103), the melt flow index is high, and when the chain extension reaction is carried out at a temperature exceeding the above range, the chain extension reaction rate increases and the pyrolysis reaction rate, which is a reverse reaction, also increases, so that the molecular weight distribution is excessively broadened, and due to oxidation products and short polymer chains generated by pyrolysis, mechanical properties may deteriorate and storage stability may be deteriorated due to rapid hydrolysis. Conversely, when the chain extension reaction is carried out at a temperature less than the above-mentioned range, the resin composition is not sufficiently melted in the reaction step, so that the reaction does not occur sufficiently, so that the effect cannot be obtained.

In the chain extension reaction step (S103), the mixing ratio of the first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester is 70: 30 to 10: 90 by weight, preferably 60 : 40 to 20: 80, more preferably 50: 50 to 30: 70. When the content of the first biodegradable aliphatic/aromatic copolyester is less than 10 parts by weight, it is difficult to realize the desired tear strength and impact strength. There are difficulties in product molding.

As the chain extender used in the chain extension reaction step (S103), one compound selected from an isocyanate compound and a carbodiimide compound may be used. In this case, as the isocyanate compound used, one selected from the group consisting of 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate and 2,2'-diphenylmethane diisocyanate may be used. can Another chain extender carbodiimide compound is 1,3-dicyclohexylcarbodiimide, HMV-8CA, HMV-10B sold by Nisshinbo, STABILIZER 9000, STABILIZER 7000 by Raschig, bis-(2,6-di one selected from the group consisting of isopropyl-phenylline-2,4-carbodiimide) and poly-(1,3,5-triisopropyl-phenyli-2,4-carbodiimide) may be used.

The reactant obtained through the chain extension reaction step (S103) has a number average molecular weight of 30,000 to 50,000, a melt flow index of 190° C. and 10 g/10 min to 25 g/10 min under measurement conditions of 2,160 g, and an acid value of 0.8 mgKOH/ g to 2.0 mgKOH/g.

The solid-state polymerization step (S105) is a step of solid-state polymerization of the chain-extended reactant through the chain extension reaction step (S103). It is a step of increasing the molecular weight by polymerization.

More specifically, the solid-state polymerization step (S105) is a step of finally preparing a biodegradable resin composition by solid-state polymerization of the resin composition after the chain extension reaction has been completed at a temperature of 60 to 110 ° C. lower than the melting point.

For the solid-state polymerization reaction in the above step, a dehumidifying dryer or vacuum dryer in which dehumidified air is supplied to the reactor can be used, and more preferably, carrying out the reaction in a vacuum dryer capable of maintaining a vacuum of less than 50 torr is to shorten the reaction time. It is advantageous. The final biodegradable resin composition obtained through solid-state polymerization can suppress side reactions by reacting below the melting temperature, and improve storage stability by improving hydrolysis resistance at the end of the resin composition, as well as with residual monomers in the resin composition. Because the content of the low molecular weight oligomer is low and the degree of crystallinity increases as the molecular weight increases, mechanical properties and processing performance can be improved.

The biodegradable resin composition prepared through the solid-state polymerization step (S105) has a melting point of 85 to 160° C., a number average molecular weight (Mn) of 45,000 to 80,000, and a weight average molecular weight (Mw) of 120,000 to 350,000, and a melt flow The index is 0.5 to 10 g/10 min at 190° C. and a load of 2.16 kg, and the acid value is 0.8 mgKOH/g to 2.0 mgKOH/g.

In addition, in the present invention, additives commonly used in the art are added to the first raw material manufacturing step (S101), the second raw material manufacturing step (S101-1) as needed to improve performance during the production of the biodegradable resin composition. Or it may be added in the chain extension reaction step (S103) step, specifically, the additive is preferably made of at least one selected from the group consisting of antioxidants, UV stabilizers and lubricants.

As the antioxidant, it is preferable to use a phenol-based antioxidant, and specifically, Adekastab AO series, Irgafos series, or mixtures thereof may be used. The antioxidant may be mixed in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the biodegradable resin composition.

The UV stabilizer may use a HALS-based compound having an amine group, and the UV stabilizer may be mixed in an amount of 0.1 to 0.8 parts by weight based on 100 parts by weight of the biodegradable resin composition.

The lubricant may be an amide-based PE wax, and the lubricant may be mixed in an amount of 0.1 to 1.0 parts by weight based on 100 parts by weight of the biodegradable resin composition.

In addition, the biodegradable resin composition prepared through the present invention can be used by compounding with a single component or a mixed component of polylactic acid or thermoplastic starch, which is known and commercialized as an existing naturally-derived resin composition, and the amount used is the natural origin of the present invention. The amount of the biodegradable resin composition (C) and the polylactic acid or thermoplastic starch alone or mixed is in the range of 60: 40 to 90: 10 by weight.

Hereinafter, a method for producing a naturally-derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance according to the present invention and physical properties of the biodegradable resin composition prepared through the method will be described with reference to Examples.

<Preparation Example> Preparation of polyfunctional compound

A 1,000 mL round-bottom flask was replaced with nitrogen, 268.16 g of DL-malic acid, 132.14 g of hydroquinone, and 0.02 g of monobutyltin oxide as a catalyst were added, followed by an esterification reaction at 210° C. for 210 minutes, a byproduct of the reaction When 2 moles of the theoretical amount of phosphorus water flowed out, it was confirmed that the reaction was complete, and the reaction was terminated to prepare a polyfunctional compound. The manufacturing process of the polyfunctional compound is shown in Scheme 2 below.

[Scheme 2]

(In Scheme 1, m is an integer from 1 to 30.)

<Example 1>

1-1. Preparation of biodegradable aliphatic/aromatic copolyester (A)

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 17.48 kg, 1,4-butanediol 11.25 kg, 300 g of the polyfunctional compound obtained in Preparation Example, and 9.6 g of tetrabutyl titanate, a catalyst, were added, and then the reactor temperature was stirred while stirring. was finally fixed at 195° C. by raising the temperature, and then methanol was drained. Then, 16.71 kg of naturally-derived sebacic acid, 3.25 kg of naturally-derived succinic acid, and 11.25 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at a temperature of 240° C. under a reduced pressure of 1.5 torr for 204 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (A).

1-2. Preparation of biodegradable aliphatic/aromatic copolyester (B)

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 17.48 kg, 1,4-butanediol 10.81 kg, 250 g of the polyfunctional compound obtained in Preparation Example, and 9.6 g of tetrabutyl titanate, a catalyst, were added, and then the reactor temperature was stirred while stirring. After the temperature was raised and finally fixed at 200 °C, methanol was discharged. Then, 12.99 kg of naturally-derived succinic acid and 10.81 kg of 1,4-butanediol were put into the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at a temperature of 245° C. under a reduced pressure of 1.5 torr for 192 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (B).

1-3. Preparation of a naturally-derived biodegradable resin composition (C)

100 kg of the naturally-derived biodegradable aliphatic/aromatic copolyester resins (A) and (B) obtained above were mixed in 10: 90 parts by weight to prepare 100 kg, and then 500 g of 1,6-hexamethylene diisocyanate was mixed with a super mixer. After mixing, a chain extension reaction was carried out at 145° C. with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization apparatus equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 95° C. for 12 hours to obtain a final naturally-derived biodegradable resin composition (C).

<Example 2>

2-1. Preparation of biodegradable aliphatic/aromatic copolyester (A)

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 18.64 kg, 1,4-butanediol 11.25 kg, 325 g of the polyfunctional compound obtained in Preparation Example, and 9.6 g of tetrabutyl titanate as a catalyst were added, and then the reactor temperature was stirred while stirring. was finally fixed at 195° C. by raising the temperature, and then methanol was drained. Then, 12.64 kg of naturally-derived sebacic acid, 4.91 kg of naturally-derived succinic acid, and 11.25 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at a temperature of 240° C. under a reduced pressure of 1.5 torr for 204 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (A).

2-2. Preparation of biodegradable aliphatic/aromatic copolyester (B)

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 18.64 kg, 1,4-butanediol 10.81 kg, 250 g of the polyfunctional compound obtained in Preparation Example, and 9.6 g of tetrabutyl titanate, a catalyst, were added, and then the reactor temperature was stirred while stirring. After the temperature was raised and finally fixed at 200 °C, methanol was discharged. Then, 12.28 kg of naturally-derived succinic acid and 10.81 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at a temperature of 245° C. under a reduced pressure of 1.5 torr for 186 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (B).

2-3. Preparation of a naturally-derived biodegradable resin composition (C)

After preparing 100 kg by mixing the biodegradable aliphatic/aromatic copolyesters (A) and (B) obtained above in a weight ratio of 70: 30, 500 g of 1,6-hexamethylene diisocyanate was mixed using a super mixer. A chain extension reaction was carried out at 140°C with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization device equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 95° C. for 8 hours to obtain a final naturally-derived biodegradable resin composition (C).

<Example 3>

3-1. Preparation of biodegradable aliphatic/aromatic copolyester (A)

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 15.53 kg, 1,4-butanediol 11.25 kg, 280 g of the polyfunctional compound obtained in Preparation Example, and 9.6 g of tetrabutyl titanate as a catalyst were added, and then the reactor temperature was stirred while stirring. was finally fixed at 195° C. by raising the temperature, and then methanol was drained. Then, 14.58 kg of naturally-derived sebacic acid, 5.67 kg of naturally-derived succinic acid, and 11.25 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at a temperature of 240° C. under a reduced pressure of 1.5 torr for 205 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (A).

3-2. Preparation of biodegradable aliphatic/aromatic copolyester (B)

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 18.64 kg, 1,4-butanediol 10.81 kg, 250 g of the polyfunctional compound obtained in Preparation Example, and 9.6 g of tetrabutyl titanate, a catalyst, were added, and then the reactor temperature was stirred while stirring. After the temperature was raised and finally fixed at 200 °C, methanol was discharged. Then, 12.28 kg of naturally-derived succinic acid and 10.81 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at a temperature of 245° C. under a reduced pressure of 1.5 torr for 198 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (B).

3-3. Preparation of a naturally-derived biodegradable resin composition (C)

After preparing 100 kg by mixing the biodegradable aliphatic/aromatic copolyesters (A) and (B) obtained above in a weight ratio of 50: 50, 500 g of 1,6-hexamethylene diisocyanate was mixed using a super mixer. A chain extension reaction was carried out at 140°C with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization device equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 95° C. for 8 hours to obtain a final naturally-derived biodegradable resin composition (C).

<Example 4>

4-1. Preparation of biodegradable aliphatic/aromatic copolyester (A)

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 17.48 kg, 1,4-butanediol 11.25 kg, 300 g of the polyfunctional compound obtained in Preparation Example, and 9.6 g of tetrabutyl titanate, a catalyst, were added, and then the reactor temperature was stirred while stirring. was finally fixed at 195° C. by raising the temperature, and then methanol was drained. Then, 16.70 kg of naturally-derived sebacic acid, 3.25 kg of naturally-derived succinic acid, and 11.25 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at a temperature of 240° C. under a reduced pressure of 1.5 torr for 212 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (A).

4-2. Preparation of biodegradable aliphatic/aromatic copolyester (B)

The 100L reactor was replaced with nitrogen, 15.95 kg of phthalic acid, 13.0 kg of naturally-derived succinic acid, 21.62 kg of 1,4-butanediol and 400 g of the polyfunctional compound obtained in Preparation Example were added, and then the temperature of the reactor was raised while stirring. Finally, after fixing at 238° C., water was drained. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of tetrabutyl titanate, and 15 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water flowed out, the temperature was continuously increased and a polycondensation reaction was carried out at a temperature of 250° C. under a reduced pressure of 1.5 torr for 188 minutes to obtain a biodegradable aliphatic/aromatic polyester resin composition (B). At this time, 20 g of tetrabutyl titanate as a catalyst and 20 g of trimethylphosphite as a stabilizer were added.

4-3. Preparation of a naturally-derived biodegradable resin composition (C)

After preparing 100 kg by mixing the biodegradable aliphatic/aromatic copolyesters (A) and (B) obtained above in a weight ratio of 20:80, 500 g of 1,6-hexamethylene diisocyanate was mixed using a super mixer. A chain extension reaction was carried out at 140°C with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization apparatus equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 95° C. for 8.5 hours to obtain a final naturally-derived biodegradable resin composition (C).

<Example 5>

5-1. Preparation of biodegradable aliphatic/aromatic copolyester (A)

A 100 L reactor was replaced with nitrogen, and 15.95 kg of phthalic acid, 12.64 kg of naturally-derived sebacic acid, 4.91 kg of naturally-derived succinic acid, 22.53 kg of 1,4-butanediol, 380 g of the polyfunctional compound obtained in Preparation Example and catalyst After 9.6 g of phosphorus tetrabutyl titanate was added, the temperature of the reactor was raised while stirring, and the temperature was finally fixed at 238° C., and then water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of tetrabutyl titanate, and 15 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water flowed out, the temperature was continuously increased and a polycondensation reaction was carried out at a temperature of 250° C. under a reduced pressure of 1.5 torr for 210 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (A). At this time, 20 g of tetrabutyl titanate as a catalyst and 20 g of trimethylphosphite as a stabilizer were added.

5-2. Preparation of biodegradable aliphatic/aromatic copolyester (B)

After replacing the 100L reactor with nitrogen, 14.95 kg of phthalic acid, 12.99 kg of naturally-derived succinic acid, 21.62 kg of 1,4-butanediol and 350 g of the polyfunctional compound obtained in Preparation Example were added, and then the temperature of the reactor was raised while stirring. Finally, after fixing at 238° C., water was drained. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of tetrabutyl titanate, and 15 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water flowed out, the temperature was continuously increased and a polycondensation reaction was carried out at a temperature of 250° C. under a reduced pressure of 1.5 torr for 201 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (B). At this time, 18 g of tetrabutyl titanate as a catalyst and 18 g of trimethylphosphite as a stabilizer were added.

5-3. Preparation of a naturally-derived biodegradable resin composition (C)

After preparing 100 kg by mixing the biodegradable aliphatic/aromatic copolyesters (A) and (B) obtained in Examples 5-1 and 5-2 in a weight ratio of 70:30, 550 g of 1,6-hexamethylene diisocyanate After mixing using a supermixer, a chain extension reaction was carried out at 140° C. with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization device equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 95° C. for 9 hours to obtain a final naturally-derived biodegradable resin composition (C).

<Example 6>

6-1. Preparation of biodegradable aliphatic/aromatic copolyester (A)

A 100 L reactor was replaced with nitrogen, isophthalic acid 13.29 kg, naturally-derived sebacic acid 14.58 kg, naturally-derived succinic acid 4.91 kg, 1,4-butanediol 22.53 kg, the polyfunctional compound obtained in Preparation Example 385 g, and the catalyst tetrabutyl After adding 9.6 g of titanate, the temperature of the reactor was raised while stirring and finally fixed at 238° C., and then water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of tetrabutyl titanate, and 15 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water flowed out, the temperature was continuously increased, and a polycondensation reaction was performed at 250° C. under a reduced pressure of 1.5 torr for 211 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition (A). At this time, 20 g of tetrabutyl titanate as a catalyst and 20 g of trimethylphosphite as a stabilizer were added.

6-2. Preparation of biodegradable aliphatic/aromatic copolyester (B)

The 100L reactor was replaced with nitrogen, and 18.64 kg of isophthalic acid, 12.28 kg of naturally-derived succinic acid, 21.62 kg of 1,4-butanediol and 350 g of the polyfunctional compound obtained in Preparation Example were added, and then the temperature of the reactor was raised while stirring and finally 238 After fixing at ℃, water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of tetrabutyl titanate, and 15 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water flowed out, the temperature was continuously increased and a polycondensation reaction was carried out at a temperature of 250° C. under a reduced pressure of 1.5 torr for 204 minutes to obtain an aliphatic/aromatic polyester resin composition (B). At this time, 18 g of tetrabutyl titanate as a catalyst and 18 g of trimethylphosphite as a stabilizer were added.

6-3. Preparation of a naturally-derived biodegradable resin composition (C)

After preparing 100 kg by mixing the biodegradable aliphatic/aromatic copolyesters (A) and (B) obtained in Examples 6-1 and 6-2 in a weight ratio of 40: 60, 1,6-hexamethylene diisocyanate 550 g After mixing using a supermixer, a chain extension reaction was carried out at 140° C. with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization apparatus equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 95° C. for 10 hours to obtain a final naturally-derived biodegradable resin composition (C).

<Comparative Example 1>

The 100L reactor was replaced with nitrogen, dimethyl terephthalate 17.48 kg, 1,4-butanediol 10.81 kg, and catalyst tetrabutyl titanate 9.6 g were added, and then the temperature of the reactor was raised while stirring. spilled out Then, 12.98 kg of naturally-derived succinic acid and 11.72 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at 245° C. under a reduced pressure of 1.5 torr for 252 minutes to obtain a biodegradable resin composition.

<Comparative Example 2>

The 100 L reactor was replaced with nitrogen, dimethyl terephthalate 17.48 kg, 1,4-butanediol 22.53 kg, and catalyst tetrabutyl titanate 10.4 g were added, and then the temperature of the reactor was raised while stirring, and finally fixed at 200 ° C. and methanol was added. spilled out Then, 16.7 kg of naturally-derived sebacic acid and 3.24 kg of naturally-derived succinic acid were added to the reactor, the reaction temperature was raised, and finally fixed at 203° C., and the theoretical amount of water was discharged. At this time, 8 g of dibutyltin oxide as a catalyst, 8 g of titanium isopropoxide, and 15 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at 245° C. under a reduced pressure of 1.5 torr for 268 minutes to obtain a biodegradable resin composition.

< Comparative Example 3>

A 100 L reactor was replaced with nitrogen, dimethyl terephthalate 18.64 kg, 1,4-butanediol 10.81 kg, and tetrabutyl titanate 9.6 g as a catalyst were added, and then the temperature of the reactor was raised while stirring and finally fixed at 200 ° C., followed by methanol was leaked Then, 12.28 kg of naturally-derived succinic acid and 10.81 kg of 1,4-butanediol were added to the reactor, the reaction temperature was raised, and finally fixed at 205° C., and then the theoretical amount of water was discharged. At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium isopropoxide, and 20 g of trimethyl phosphate as a stabilizer were added. Thereafter, the temperature of the reactor was raised and a polycondensation reaction was performed at 245° C. under a reduced pressure of 1.5 torr for 278 minutes to obtain a naturally-derived aliphatic/aromatic polyester resin composition. Then, 100 kg of the resin composition obtained through the polycondensation reaction and 500 g of 1,6-hexamethylene diisocyanate were mixed using a supermixer, and then a chain extension reaction was carried out at 125° C. using a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization apparatus equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 80° C. for 8 hours to obtain a biodegradable resin composition.

< Comparative Example 4>

After replacing the 100L reactor with nitrogen, 15.95 kg of phthalic acid, 12.63 kg of naturally-derived sebacic acid, 4.91 kg of naturally-derived succinic acid, and 23.43 kg of 1,4-butanediol were added, and the temperature of the reactor was raised while stirring. Finally, after fixing at 235°C, water was drained . At this time, 10 g of dibutyltin oxide as a catalyst, 10 g of titanium propoxide, and 20 g of trimethyl phosphate as a stabilizer were added. After the theoretical amount of water flowed out, the temperature was continuously increased, and a polycondensation reaction was performed at a temperature of 250° C. under a reduced pressure of 1.5 torr for 325 minutes to obtain an aliphatic polyester resin composition. At this time, 20 g of tetrabutyl titanate as a catalyst and 20 g of trimethylphosphite as a stabilizer were added. Then, 100 kg of the resin composition obtained through the polycondensation reaction and 500 g of 1,6-hexamethylene diisocyanate were mixed using a supermixer, and then a chain extension reaction was performed at 125° C. with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization apparatus equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 80° C. for 8 hours to obtain a biodegradable resin composition.

<Comparative Example 5>

The biodegradable aliphatic/aromatic copolyester composition of Comparative Examples 1 and 2 was mixed using a supermixer in a weight ratio of 10: 90 to prepare 100 kg, and then compounded at 140° C. with a twin-screw extruder having a diameter of 58 mm to mix the biodegradable resin A composition was prepared.

<Comparative Example 6>

100 kg was prepared by mixing the biodegradable aliphatic/aromatic copolyester resin composition of Comparative Examples 1 and 2 in a weight ratio of 70: 30, 1,6-hexamethylene diisocyanate 550 g was added, and then mixed using a super mixer. A chain extension reaction was carried out at 140°C with a twin-screw extruder having a diameter of 58 mm. Then, the reactant obtained by the chain extension reaction was put into a solid-state polymerization device equipped with a vacuum pump, and the solid-state polymerization reaction was performed at 95° C. for 10 hours to obtain a naturally-derived biodegradable resin composition.

<Comparative Example 7>

The biodegradable aliphatic/aromatic copolyester compositions of Comparative Examples 3 and 4 were mixed using a supermixer in a weight ratio of 10: 90, and then compounded at 140° C. with a twin-screw extruder having a diameter of 58 mm. A naturally-derived biodegradable resin mixture composition got

<Experimental Example 1> Measurement of molecular weight, melting point, melt flow index, and acid value

In order to confirm the number average molecular weight, weight average molecular weight, melting point, melt flow index and acid value for the naturally-derived biodegradable resin composition of Examples 1 to 6 and the resin composition prepared in Comparative Examples 1 to 7, the following method was used. evaluated. The results are shown in Table 1 below.

[Assessment Methods]

(1) Number average molecular weight and weight average molecular weight

The number average molecular weight and the weight average molecular weight distribution were measured using a gel permeation chromatography analysis method at 35° C. using an equipment equipped with a column filled with polystyrene. At this time, the developing solvent was chloroform, the concentration of the sample was 5 mg/mL, and the flow rate of the solvent was 1.0 mL/min.

(2) melting point

The melting point was measured from 20°C to 200°C using a differential scanning calorimeter at a temperature increase rate of 10°C per minute in a nitrogen atmosphere.

(3) melt flow index

The melt flow index was performed at 190°C and 2,160 g in accordance with the standard of ASTM D1238.

(4) acid value

For the acid value, 0.5 g of the obtained resin was completely dissolved in 30 ml of chloroform, and 20 ml of ethanol was added to prepare a final solution, followed by titration with 0.1N KOH solution.

division	number average Molecular Weight	weight average Molecular Weight	Melting point (℃)	melt flow index (g/10min)	polycondensation Reaction time (min)	acid (mgKOH/g)
Example 1	58,322	173,800	116	3.2	204/192 (A/B)	0.96
Example 2	64,900	202,488	124	2.7	204/186 (A/B)	1.24
Example 3	59,730	182,050	112	3.1	205/198 (A/B)	0.79
Example 4	53,108	175,780	121	3.9	212/188 (A/B)	0.80
Example 5	68,750	198,688	125	2.1	210/201 (A/B)	1.76
Example 6	61,270	186,874	111	3.1	211/204 (A/B)	0.88
Comparative Example 1	21,199	67,752	120	51.8	252	3.9
Comparative Example 2	17,440	69,340	113	62.0	268	3.7
Comparative Example 3	40,337	104,215	124	12.8	278	3.6
Comparative Example 4	32,289	113,157	123	21.0	325	3.2
Comparative Example 5	17,240	66,350	118	72.2	-	4.8
Comparative Example 6	41,240	129,949	119	10.3	-	3.4
Comparative Example 7	38,650	110,792	123	14.2	-	3.8

According to the results in Table 1, when the polycondensation reaction time of the resin compositions of Examples 1 to 6 using the long-chain polyfunctional compound as a reaction accelerator is compared only at the level of the polycondensation reactants of Comparative Examples 1 to 4 It was confirmed that high number average molecular weight and weight average molecular weight values were exhibited in a short reaction time. In addition, it was found that Examples 1 to 6 exhibited a lower melt flow index value and a lower acid value than Comparative Examples 1 to 7 to be advantageous in extrusion moldability and weather resistance.

On the other hand, in Comparative Examples 1 to 7, the polyfunctional compound is not included, so the polycondensation reaction takes a long time, a high acid value is high due to an increase in the reverse reaction due to a long reaction time, and the number average molecular weight and weight average molecular weight are carried out as a whole. It showed a significantly lower value compared to Examples 1 to 6, and the melt flow index was very high, and it was expected that extrusion formability, mechanical properties, and durability were weak.

<Experimental Example 2> Evaluation of mechanical properties

In order to confirm the mechanical properties of tensile strength, elongation, biodegradability and processability of the naturally-derived biodegradable resin composition of Examples 1 to 6 and the biodegradable resin composition prepared in Comparative Examples 1 to 7, the following method was used. evaluated. The results are shown in Table 2 below.

[Assessment Methods]

The measurement sample was carried out by manufacturing a 25 μm thick film with an expansion ratio of 2.0 to 1 using a blown film machine having a screw diameter of 50 mm, a die gap of 2.2 mm, and a die diameter of 100 mm.

(1) Tensile strength and elongation

Tensile strength and elongation were measured using a universal test machine by preparing a 20um blown film and preparing a specimen conforming to ASTM D638 standard.

(2) Dart impact strength

The dart impact strength was measured using a dart impact strength measuring device in a method conforming to ASTM D1709 by manufacturing a 20um blown film.

(3) Evaluation of exploded view

The sample prepared by the above method was recovered 12 months after burying at a depth of 30 cm from the soil surface and measured using the weight reduction method.

(4) Machinability

Processability was visually observed for bubble stability and wrinkling during film production. At this time, as the workability evaluation criteria, if the state of the film was good, it was indicated by ○, if it was normal, it was indicated by △, and if it was bad, it was indicated by X.

division	The tensile strength (kgf/cm2)	elongation (%)	Dart Impact Strength (g)	biodegradability (%)	machinability
Example 1	312	523	339	86.1	○
Example 2	338	436	360	79.4	○
Example 3	293	545	315	84.8	○
Example 4	283	627	492	89.2	○
Example 5	287	594	493	88.7	○
Example 6	275	586	491	86.6	○
Comparative Example 1	98	250	83	88.0	X
Comparative Example 2	102	200	78	85.6	X
Comparative Example 3	180	325	128	84.1	△
Comparative Example 4	172	350	134	82.3	△
Comparative Example 5	95	150	69	87.6	X
Comparative Example 6	192	350	137	83.5	△
Comparative Example 7	182	350	133	82.1	△
* Processability evaluation criteria: ○ Good, △ Normal, X Poor

According to the results of Table 2, in the case of Examples 1 to 6, compared with Comparative Examples 1 to 7, tensile strength, elongation, impact strength and mechanical properties of workability were significantly improved, whereas in the biodegradability test results, It was confirmed that they have similar biodegradability.

On the other hand, Comparative Examples 1 to 7 showed excellent biodegradability of 82.1% or more, but this was only due to the low molecular weight. was significantly reduced, and it was confirmed that the workability was not good at an average or poor level.

<Experimental Example 3> Weather resistance evaluation

The naturally-derived biodegradable resin composition of Examples 1 to 6 and the resin composition prepared in Comparative Examples 1 to 7 were left at a temperature of 25° C. and a relative humidity of 75%, and then samples were collected every 6 months and the number average The change in molecular weight is measured and compared with the initial value, and the film produced by the method of Experimental Example 2 is left at a temperature of 25° C. and a relative humidity of 75%, and then a sample is taken every 6 months to measure the tensile strength and elongation. Thus, the change over time was confirmed by comparing it with the initial value.

division	The tensile strength (kgf/cm2)			elongation (%)			number average molecular weight
	Early	6 months after	after 12 months	Early	6 months after	after 12 months	Early	6 months after	12 months after
Example 1	312	306	293	523	513	492	58,322	57,214	54,823
Example 2	338	329	325	436	424	419	64,900	63,083	62,369
Example 3	293	287	281	545	535	523	59,730	58,595	57,284
Example 4	283	275	268	627	609	594	53,108	51,621	50,346
Example 5	287	280	272	594	579	564	68,750	66,963	63,547
Example 6	275	268	260	586	572	554	61,270	59,800	56,570
Comparative Example 1	98	92	74	250	238	185	21,199	20,139	15,800
Comparative Example 2	102	95	77	200	190	150	17,440	16,568	13,080
Comparative Example 3	180	168	135	325	309	225	40,337	38,320	30,250
Comparative Example 4	172	160	129	350	333	250	32,289	30,675	24,217
Comparative Example 5	95	90	71	150	143	125	17,240	16,378	12,980
Comparative Example 6	192	180	144	350	333	260	41,240	39,178	30,950
Comparative Example 7	182	172	137	350	333	250	38,650	36,718	28,900

According to the results of Table 3, in the case of Examples 1 to 6, compared with Comparative Examples 1 to 7, the width of the change over time of the physical properties and the decrease in the number average molecular weight was significantly smaller, it was confirmed to have excellent durability.

Therefore, the biodegradable resin composition having excellent mechanical properties, moldability and weather resistance according to the present invention and a method for manufacturing the same are environmentally friendly, exhibit excellent biodegradability, and provide a biodegradable resin composition having excellent mechanical properties, moldability and weather resistance. to provide.

[Explanation of code]

S101; 1st raw material manufacturing stage

S101-1; 2nd raw material manufacturing stage

S103; chain extension reaction step

S105 ; solid-state polymerization

Claims (19)

1. A naturally-derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance comprising a first biodegradable aliphatic/aromatic copolyester, a second biodegradable aliphatic/aromatic copolyester, and a chain extender, comprising:

   The first biodegradable aliphatic/aromatic copolyester is a mixture of a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid composed of a naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and a naturally-derived aliphatic dicarboxylic acid having 10 carbon atoms. It is characterized in that it is prepared through an esterification reaction and a polycondensation reaction of an acid component and an aliphatic diol comprising

   The second biodegradable aliphatic/aromatic copolyester is prepared through esterification and polycondensation of an acid component and an aliphatic diol including a mixed component of a naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and an aromatic dicarboxylic acid. A naturally derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance, characterized in that.
2. According to claim 1,

   The aromatic dicarboxylic acid is a naturally derived biodegradable resin composition, characterized in that it consists of at least one selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthoic acid, and esterified derivatives thereof.
3. According to claim 1,

   The aliphatic diol is a naturally-derived biodegradable resin composition, characterized in that it consists of at least one selected from the group consisting of C ₂ to C ₁₂ linear aliphatic diol and C ₅ to C ₁₅ cycloaliphatic diol.
4. According to claim 1,

   The acid component of the first biodegradable aliphatic/aromatic copolyester is a naturally-derived biodegradable resin composition, characterized in that a naturally-derived aliphatic dicarboxylic acid and an aromatic dicarboxylic acid are mixed in a molar ratio of 65: 35 to 50: 50.
5. 4. The method of claim 1 or 3,

   The naturally-derived aliphatic dicarboxylic acid of the first biodegradable aliphatic/aromatic copolyester is a naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and a naturally-derived aliphatic dicarboxylic acid having 10 carbon atoms in a molar ratio of 75: 25 to 25: 75 A naturally-derived biodegradable resin composition, characterized in that it is mixed with
6. According to claim 1,

   The first biodegradable aliphatic/aromatic copolyester is a naturally-derived biodegradable resin composition, characterized in that the acid component and the aliphatic diol are mixed in a molar ratio of 1: 25 to 1: 1.5.
7. According to claim 1,

   Naturally-derived biodegradable resin composition, characterized in that the second biodegradable aliphatic/aromatic copolyester is mixed with a naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and an aromatic dicarboxylic acid in a molar ratio of 55:45 to 50:50.
8. According to claim 1,

   The second biodegradable aliphatic/aromatic copolyester is a naturally-derived biodegradable resin composition, characterized in that the acid component and the aliphatic diol are mixed in a molar ratio of 1: 1.10 to 1: 1.35.
9. According to claim 1,

   The first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester are 70: 30 to 10: a naturally derived biodegradable resin composition, characterized in that mixed in a weight ratio of 90.
10. According to claim 1,

    The first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester are naturally-derived biodegradable resin composition, characterized in that it is prepared in the presence of a polyfunctional compound of Formula 1 below.

    [Formula 1]

    

    (In Formula 1, m is an integer of 1 to 30.)
11. According to claim 1,

    The chain extender is a naturally derived biodegradable resin composition, characterized in that consisting of an isocyanate compound or a carbodiimide compound.
12. Esterification reaction of an acid component and an aliphatic diol containing a mixed component of an aromatic dicarboxylic acid and a naturally derived aliphatic dicarboxylic acid comprising a naturally derived aliphatic dicarboxylic acid having 4 carbon atoms and a naturally derived aliphatic dicarboxylic acid having 10 carbon atoms A first raw material manufacturing step of preparing a first biodegradable aliphatic/aromatic copolyester produced through a polycondensation reaction;

    A second biodegradable aliphatic/aromatic copolyester prepared through esterification and polycondensation of an acid component and an aliphatic diol containing a mixed component of a naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and an aromatic dicarboxylic acid is prepared a second raw material manufacturing step;

    Chain extension by mixing the first biodegradable aliphatic/aromatic copolyester prepared through the first raw material manufacturing step, the second biodegradable aliphatic/aromatic copolyester prepared through the second raw material manufacturing step, and a chain extender chain extension reaction step of reacting; and

    A method for producing a naturally-derived biodegradable resin composition with improved mechanical properties, moldability and weather resistance, characterized in that it comprises; a solid-state polymerization step of solid-state polymerization of a chain-extended reactant through the chain extension reaction step.
13. 13. The method of claim 12,

    The acid component of the first raw material preparation step is a method for producing a naturally-derived biodegradable resin composition, characterized in that the naturally-derived aliphatic dicarboxylic acid and the aromatic dicarboxylic acid are mixed in a molar ratio of 65: 35 to 50: 50.
14. According to claim 12 or 3,

    The naturally-derived aliphatic dicarboxylic acid in the first raw material manufacturing step is characterized in that the naturally-derived aliphatic dicarboxylic acid having 4 carbon atoms and the naturally-derived aliphatic dicarboxylic acid having 10 carbon atoms are mixed in a molar ratio of 75: 25 to 25: 75 A method for producing a naturally-derived biodegradable resin composition.
15. 13. The method of claim 12,

    In the first biodegradable aliphatic/aromatic copolyester of the first raw material manufacturing step, the acid component and the aliphatic diol are mixed in a molar ratio of 1: 25 to 1: 1.5. Preparation of a naturally-derived biodegradable resin composition Way.
16. 13. The method of claim 12,

    Naturally-derived aliphatic dicarboxylic acid and aromatic dicarboxylic acid having 4 carbon atoms in the second raw material manufacturing step are mixed in a molar ratio of 55: 45 to 50: 50. Method for producing a naturally-derived biodegradable resin composition.
17. 13. The method of claim 12,

    In the second biodegradable aliphatic/aromatic copolyester in the second raw material manufacturing step, the acid component and the aliphatic diol are mixed in a molar ratio of 1: 1.10 to 1: 1.35. Preparation of a naturally-derived biodegradable resin composition Way.
18. 13. The method of claim 12,

    The first biodegradable aliphatic/aromatic copolyester and the second biodegradable aliphatic/aromatic copolyester in the third chain extension reaction step are naturally biodegradable, characterized in that they are mixed in a weight ratio of 70: 30 to 10: 90 A method for producing a resin composition.
19. 13. The method of claim 12,

    The first biodegradable aliphatic/aromatic copolyester in the first raw material production step and the second biodegradable aliphatic/aromatic copolyester in the second raw material production step are prepared in the presence of a polyfunctional compound represented by the following formula (1) A method for producing a naturally-derived biodegradable resin composition.

    [Formula 1]

    

    (In Formula 1, m is an integer of 1 to 30.)

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