WO2018105823A1 - Polylactic acid copolymer and method for preparing same - Google Patents

Abstract

The present invention relates to a polylactic acid copolymer and a method for preparing the same and, more specifically, to a polylactic acid copolymer with improved elasticity and thermal stability compared to a polylactic acid homopolymer, by including as repeating units, (A) lactic acid, and (B) a monocyclic, polycyclic, or fused cyclic compound having a hydroxyl-tetramethylene-oxy-hydrocabon group at the terminal, and a method for preparing the same.

Description

Polylactic acid copolymer and preparation method thereof

The present invention relates to a polylactic acid copolymer and a method for producing the same, and more particularly, to (A) lactic acid as a repeating unit; And (B) a monocyclic, polycyclic, or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at its terminal; thereby, a polylactic acid copolymer having improved elasticity and thermal stability compared to a polylactic acid homopolymer. And to a method for producing the same.

In an effort to reduce carbon dioxide emissions, which are a major cause of global warming, and to replace limited expensive petroleum resources, active research on eco-friendly biomass is under way. Among them, biodegradable polylactic acid (PLA) resin obtained through fermentation of corn starch, which is easily obtained in nature, is attracting attention as a substitute material for general purpose resins because of low price and ease of supply. Application has been attempted in various ranges, such as for general molded products, for textile, medical, packaging.

       In general, the PLA polymerization method is a method of synthesizing by direct condensation polymerization from lactic acid, a method of synthesizing high molecular weight PLA through solid phase polymerization from low molecular weight PLA, and azeotropic condensation using a low boiling solvent. A method of synthesizing PLA is known, and recently, there is high interest in PLA synthesis through ring opening polymerization having an advantage of easily synthesizing various high molecular weight PLA.

However, due to the low heat resistance and impact resistance of PLA itself, polylactic acid homopolymer has a limitation in that mechanical properties such as heat resistance and impact resistance are not sufficient, and satisfies elasticity, which is a major industrial requirement such as general textile products and packaging products. Since the situation is difficult to make, the application range is not expanded.

In this regard, various attempts have been introduced to complement existing weak properties along with development to various uses (for example, Korean Patent Application Publication No. 2015-0124281 and US Patent Registration No. 8633294), but only to supplement specific properties and apply the same. The scope is limited.

The present invention is to solve the problems of the prior art as described above, and to improve the low elasticity inherent to polylactic acid (PLA) and at the same time improve the thermal stability that is a problem during processing and polylactic acid copolymer to increase the production efficiency and It is a technical subject to provide the manufacturing method.

The present invention to solve the above technical problem, (A) lactic acid as a repeating unit; And (B) a monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at the end thereof.

According to another aspect of the invention, (1) prepolymerizing lactic acid, lactic acid oligomer or lactide; And (2) copolymerizing the lactic acid prepolymer obtained in the step (1) with a monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at the terminal; A method for producing a polylactic acid copolymer is provided.

According to another aspect of the present invention, a processed resin article prepared using the polylactic acid copolymer is provided.

According to the present invention, it is possible to provide a novel biodegradable polylactic acid copolymer which significantly improves the low elasticity and thermal stability of a conventional polylactic acid homopolymer, thereby securing a processing range of the same flexibility as conventional general-purpose resins. Increasing processing efficiency, it is possible to overcome the difficulties of secondary processing due to low elasticity and thermal stability, thereby extending the scope of conventional applications of textile products, film products, packaging products and medical supplies.

Hereinafter, the present invention will be described in more detail.

The present invention provides a random or block repeating unit comprising lactic acid; And a monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at the end thereof.

The lactic acid repeating unit included in the polylactic acid copolymer of the present invention has the following structure in the copolymer.

The lactic acid repeating unit may be introduced into the copolymer by lactic acid, lactic acid oligomers or lactide (cyclic dimers of lactic acid).

The content of lactic acid included as a repeating unit in the polylactic acid copolymer of the present invention may be 70 to 99% by weight based on 100% by weight of the copolymer, preferably 85 to 98% by weight, more preferably 90 It may be ~ 97% by weight, but is not limited thereto. If the lactic acid content in the polylactic acid copolymer is less than 70% by weight, the degree of polymerization of the polylactic acid copolymer may be low and the biodegradable effect may be insignificant, and if it exceeds 99% by weight, the improvement in elasticity and thermal stability of the polylactic acid copolymer may be achieved. The effect may be low.

Monocyclic, polycyclic or fused cyclic compounds having hydroxy-tetramethylene-oxy-hydrocarbon groups at the ends, which are included as copolymerized repeating units together with lactic acid repeating units in the polylactic acid copolymers of the present invention (hereinafter “tetra Methylene glycol ether-terminal cyclic compounds ”) are hydroxy-tetramethylene-oxy groups (i.e., HO- (CH ₂ ) at the ends via a hydrocarbon group around a monocyclic, polycyclic or fused cyclic moiety) As a compound having a structure of ₄ -O-, a hydroxy-tetramethylene-oxy group is preferably present at both ends.

The content of the tetramethylene glycol ether-terminal cyclic compound included in the polylactic acid copolymer of the present invention as a repeating unit together with the lactic acid repeating unit may be 1 to 30% by weight based on 100% by weight of the copolymer. May be 2 to 15% by weight, more preferably 3 to 10% by weight, but is not limited thereto. If the content of the tetramethylene glycol ether-terminal cyclic compound as a comonomer in the polylactic acid copolymer is less than 1% by weight, the improvement effect on the elasticity and thermal stability of the polylactic acid copolymer may be insignificant, and if it is more than 30% by weight. The degree of polymerization of the polylactic acid copolymer and the biodegradability of the polylactic acid copolymer may be low.

According to one embodiment of the present invention, the tetramethylene glycol ether-terminated cyclic compound may have a structural formula represented by the following Chemical Formula 1-1.

[Formula 1-1]

HO- (CH ₂ ) _4- (OR ₁ ) -BA-B '-(R ₂ -O)-(CH ₂ ) ₄ -OH

In Chemical Formula 1-1,

R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group, wherein R ₁ and R ₂ each independently comprise one or more bonds selected from ether bonds, ester bonds, ketone bonds and urethane bonds Can do it,

B and B 'each independently represent an anhydrosugar alcohol, the anhydrosugar alcohol may be in the form of substituted or unsubstituted alkylene glycol at one or both ends thereof, the alkylene glycol is not particularly limited , Preferably ethylene glycol, propylene glycol or combinations thereof;

A is a substituted or unsubstituted divalent aliphatic or aromatic monocyclic, polycyclic or fused cyclic group; Or a substituted or unsubstituted divalent monoheterocyclic, polyheterocyclic or fused heterocyclic group comprising at least one hetero atom selected from N, O and S, wherein A is an ester group, ether It may comprise one or more functional groups selected from the group consisting of groups, thioether groups, ketone groups and urethane groups.

As used herein, the term “hydrocarbon group” refers to a linear, branched or cyclic saturated or unsaturated hydrocarbon group, which may include, but is not limited to, saturated or unsaturated alkyl, alkoxy, aryl and combinations thereof.

In addition, in the present specification, the term “substituted” or “substituted” means that a hydrogen atom is a halogen atom (eg, Cl or Br, etc.), a hydroxyl group, an alkyl group having 1 to 13 carbon atoms (eg, methyl, ethyl or propyl). Etc.), an alkoxy group having 1 to 13 carbon atoms (e.g., methoxy, ethoxy or propoxy), an aryl group having 6 to 10 carbon atoms (e.g., phenyl, chlorophenyl or tolyl, etc.), or these It means what was substituted by substituents, such as a combination.

In addition, in the present specification, the term “anhydrous alcohol” is obtained by removing one or more water molecules from a compound obtained by adding hydrogen to a reducing terminal group of a saccharide, called hydrogenated sugar or sugar alcohol. It means any substance.

In addition, in the present specification, the term “anhydrosugar alcohol substituted with alkylene glycol (hereinafter referred to as“ anhydrosugar alcohol-alkylene glycol ”)” refers to the terminal (eg, both ends) hydroxyl group of the anhydrosugar alcohol. As an adduct obtained by reacting an alkylene oxide (eg, C ₁ -C ₄ alkylene oxide, more specifically ethylene oxide, propylene oxide or mixtures thereof), the terminal (eg, amount of anhydrosugar alcohol) Terminal) means a compound of the form in which hydrogen of the hydroxyl group is substituted with hydroxyalkylene oxide of alkylene oxide. For example, the result of adding ethylene oxide to both terminal hydroxyl groups of isosorbide is as follows.

More specifically in Chemical Formula 1-1,

R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group having 12 to 328 carbon atoms, wherein R ₁ and R ₂ are each independently from an ether bond, an ester bond, a ketone bond and a urethane bond May comprise one or more bonds selected;

B and B 'each independently represent dianhydrohexitol, preferably isosorbide (1,6- dianhydrosorbitol), isomannide (1,6- dianhydromannitol) or isoidide (1, 6- dianhydroiditol), the dianhydrohexitol may be a substituted or unsubstituted form of alkylene glycol at one or both ends thereof, the alkylene glycol is not particularly limited, Preferably ethylene glycol, propylene glycol or combinations thereof;

A is a substituted or unsubstituted divalent, aliphatic having 5 to 30 carbon atoms or an aromatic monocyclic, polycyclic or fused cyclic group having 6 to 30 carbon atoms; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having 5 to 30 ring atoms, including one or more hetero atoms selected from N, O and S. And A may also include one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups.

More specifically in Chemical Formula 1-1,

R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group having 12 to 248 carbon atoms, wherein R ₁ and R ₂ are each independently from an ether bond, an ester bond, a ketone bond and a urethane bond May comprise one or more bonds selected;

B and B 'each independently represent dianhydrohexitol, preferably isosorbide (1,6- dianhydrosorbitol), isomannide (1,6- dianhydromannitol) or isoidide (1, 6- dianhydroiditol), the dianhydrohexitol may be a substituted or unsubstituted form of alkylene glycol at one or both ends thereof, the alkylene glycol is not particularly limited, Preferably ethylene glycol, propylene glycol or combinations thereof;

A is a substituted or unsubstituted divalent, aromatic monocyclic, polycyclic or fused cyclic group having 6 to 20 carbon atoms in total; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having from 5 to 20 ring atoms, including one or more hetero atoms selected from N, O and S. And A may also include one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups.

According to one preferred embodiment of the present invention, the tetramethylene glycol ether-terminated cyclic compound may have a structural formula represented by Formula 1-2.

[Formula 1-2]

HO- (CH ₂ ) _4- (OR ₃ ) _n -CBA-B'-C '-(R ₄ -O) _m- (CH ₂ ) ₄ -OH

In Chemical Formula 1-2,

R ₃ and R ₄ each independently represent a substituted or unsubstituted divalent hydrocarbon group;

C and C 'each independently represent a substituted or unsubstituted divalent aliphatic or aromatic hydrocarbon group comprising one or more bonds selected from ether bonds, ester bonds, ketone bonds and urethane bonds;

B and B 'each independently represent an anhydrosugar alcohol, the anhydrosugar alcohol may be in the form of substituted or unsubstituted alkylene glycol at one or both ends thereof, the alkylene glycol is not particularly limited , Preferably ethylene glycol, propylene glycol or combinations thereof;

A is a substituted or unsubstituted divalent aliphatic or aromatic monocyclic, polycyclic or fused cyclic group; Or a substituted or unsubstituted divalent monoheterocyclic, polyheterocyclic or fused heterocyclic group comprising at least one hetero atom selected from N, O and S, wherein A is an ester group, ether May comprise one or more functional groups selected from the group consisting of groups, thioether groups, ketone groups and urethane groups;

n and m each independently represent the integer of 1-80.

More specifically, in Chemical Formula 1-2,

R ₃ and R ₄ each independently represent a substituted or unsubstituted alkylene group;

C and C 'each independently represent a divalent, aliphatic having 3 to 13 carbon atoms or an aromatic hydrocarbon group having 8 to 32 carbon atoms, including one or more bonds selected from ether bonds, ester bonds, ketone bonds, and urethane bonds;

B and B 'each independently represent dianhydrohexitol, preferably isosorbide (1,6- dianhydrosorbitol), isomannide (1,6- dianhydromannitol) or isoidide (1, 6- dianhydroiditol), the dianhydrohexitol may be a substituted or unsubstituted form of alkylene glycol at one or both ends thereof, the alkylene glycol is not particularly limited, Preferably ethylene glycol, propylene glycol or combinations thereof;

A is a substituted or unsubstituted divalent, aliphatic having 5 to 30 carbon atoms or an aromatic monocyclic, polycyclic or fused cyclic group having 6 to 30 carbon atoms; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having 5 to 30 ring atoms, including one or more hetero atoms selected from N, O and S. And A may also include one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups;

n and m each independently represent the integer of 1-70.

More specifically, in Chemical Formula 1-2,

R ₃ and R ₄ are each independently a substituted or unsubstituted alkylene group having 2 to 6 carbon atoms, preferably a substituted or unsubstituted alkylene group having 3 to 5 carbon atoms, more preferably a substituted or unsubstituted group Represented tetramethylene group;

C and C 'each independently represent a divalent, aromatic hydrocarbon group having 8 to 22 carbon atoms in total including one or more bonds selected from ether bonds, ester bonds, ketone bonds and urethane bonds;

B and B 'each independently represent dianhydrohexitol, preferably isosorbide (1,6- dianhydrosorbitol), isomannide (1,6- dianhydromannitol) or isoidide (1, 6- dianhydroiditol), the dianhydrohexitol may be a substituted or unsubstituted form of alkylene glycol at one or both ends thereof, the alkylene glycol is not particularly limited, Preferably ethylene glycol, propylene glycol or combinations thereof;

A is a substituted or unsubstituted divalent, aromatic monocyclic, polycyclic or fused cyclic group having 6 to 20 carbon atoms in total; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having from 5 to 20 ring atoms, including one or more hetero atoms selected from N, O and S. And A may also include one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups;

n and m each independently represent the integer of 1-60.

According to one preferred embodiment of the present invention, the tetramethylene glycol ether-terminated cyclic compound may have a structural formula represented by Chemical Formula 1-3.

[Formula 1-3]

In Chemical Formula 1-3,

n represents the integer of 1-80, Preferably it is 1-70, More preferably, it is 1-60.

According to another embodiment of the present invention, the tetramethylene glycol ether-terminated cyclic compound may have a structural formula represented by the following Chemical Formula 2-1.

[Formula 2-1]

HO- (CH ₂ ) _4- (OR ₁ ) -A- (R ₂ -O)-(CH ₂ ) ₄ -OH

In Chemical Formula 2-1,

R ₁ , R ₂ and A are as defined in Formula 1-1.

According to another preferred embodiment of the present invention, the tetramethylene glycol ether-terminal cyclic compound may have a structural formula represented by the following formula (2-2).

[Formula 2-2]

HO- (CH ₂ ) _4- (OR ₃ ) _n -C- A- C '-(R ₄ -O) _m- (CH ₂ ) ₄ -OH

In Chemical Formula 2-2,

R ₃ , R ₄ , C, C ', A, n and m are as defined in Formula 1-2 above.

According to another preferred embodiment of the present invention, the tetramethylene glycol ether-terminal cyclic compound may have a structural formula represented by the following formula 2-3, 2-4 or 2-5.

[Formula 2-3]

In Chemical Formula 2-3,

n represents an integer of 2 to 80, preferably 2 to 70, more preferably 2 to 60.

[Formula 2-4]

In Chemical Formula 2-4,

n represents the integer of 1-80, Preferably it is 1-70, More preferably, it is 1-60.

[Formula 2-5]

In Chemical Formula 2-5,

n represents the integer of 1-80, Preferably it is 1-70, More preferably, it is 1-60.

There is no particular limitation on the method for producing the tetramethylene glycol ether-terminated cyclic compound, which is included as a repeating unit in the polylactic acid copolymer of the present invention.

According to one embodiment of the present invention, a monocyclic, polycyclic or fused solution of anhydrous sugar alcohol (eg, isosorbide, isomannide, isoidide, etc.) dissolved in an ethylene acetate solvent or a methylene chloride solvent After cyclic dicarboxylic acid or its diester (for example, dimethyl terephthalate, etc.) is first reacted, polytetramethylene ether glycol (PTMEG) is added to perform a secondary reaction, followed by alkaline solution. By removing the secondary reactant through several washing with water and several washing with distilled water, and removing the solvent through vacuum reduced pressure, the tetramethylene glycol ether-terminated cyclic compound of Formula 1-3 can be prepared.

According to another embodiment of the invention, aromatic monocyclic, polycyclic or fused cyclic compounds having a total of 6 to 30 carbon atoms dissolved in ethylene acetate solvent or methylene chloride solvent (e.g., naphthalenedicarboxylic acid, naphthalenedicar After reacting the PTMEG with a solution such as a carboxylate, the secondary reactant is removed by several washings with an alkaline solution and several washings with distilled water, and the solvent is removed by vacuum depressurization, thereby removing Methylene glycol ether-terminated cyclic compounds can be prepared.

According to another embodiment of the present invention, aromatic monocyclic, polycyclic or fused cyclic compounds having 6 to 30 carbon atoms dissolved in ethylene acetate solvent or methylene chloride solvent (e.g., diphenol, naphthalenediol and the like) ) The solution and the monocyclic, polycyclic or fused cyclic dicarboxylic acid or diester thereof (e.g., dimethyl terephthalate, etc.) and then polytetramethylene ether glycol (PTMEG) The reaction was carried out by adding a secondary reaction, and then the secondary reactant was removed through several washings with an alkaline solution and several washings with distilled water, and the solvent was removed by vacuum decompression, thereby the chemical formula 2-4 or 2-5 Tetramethylene glycol ether-terminated cyclic compounds can be prepared.

In addition to the lactic acid repeating unit and the tetramethylene glycol ether-terminated cyclic compound repeating unit, the copolymer of the present invention may further include one or more additional copolymerization repeating units within the scope of achieving the object of the present invention. There is no particular limitation on the kind of such additional copolymerized repeating units. For example, the copolymer repeating unit that may be further included in the copolymer of the present invention may include polyether, diol, and the like.

According to another aspect of the invention, (1) prepolymerizing lactic acid, lactic acid oligomer or lactide; And (2) a monocyclic, polycyclic or fused cyclic compound having a lactic acid prepolymer obtained in step (1) and a hydroxy-tetramethylene-oxy-hydrocarbon group at the end thereof (hereinafter, “tetramethylene glycol ether- A method for producing a polylactic acid copolymer is provided.

There is no particular limitation on the method or condition for prepolymerizing the lactic acid, the lactic acid oligomer (eg, number average molecular weight (Mn) 100 to 5,000) or lactide in step (1), and generally known methods or conditions may be used. Although not limited thereto, according to one embodiment of the present invention, in the presence of a catalyst, lactic acid, lactic acid oligomer or lactide is raised at elevated temperature (eg, 100 to 210 ° C, more specifically 110 to 150 ° C) and reduced pressure conditions. A prepolymer can be manufactured by making reaction for a suitable time (for example, 0.1 to 2 hours, more specifically 0.2 to 1.5 hours). The number average molecular weight (Mn) of the obtained lactic acid prepolymer may be, for example, 2,000 to 10,000, but is not limited thereto.

Catalysts that can be used for the preliminary polymerization of lactic acid are, for example, zinc oxide, antimony oxide, antimony chloride, lead oxide, calcium oxide, aluminum oxide, iron oxide, calcium chloride, zinc acetate, paratoluene sulfonic acid, tin tin, First tin sulfate, first tin oxide, second tin oxide, first tin octanoate, tetraphenyl tin, tin powder, titanium tetrachloride, or mixtures thereof. The catalyst may be used in an amount of 0.0005 to 5 parts by weight, preferably 0.003 to 1 part by weight based on 100 parts by weight of lactic acid, lactic acid oligomer or lactide. When the amount of the catalyst used is less than 0.0005 parts by weight, the reaction rate is slowed. When the amount of the catalyst used is more than 5 parts by weight, the residual catalyst may discolor the product or degrade the physical properties.

In step (2), the lactic acid prepolymer obtained in step (1) is copolymerized with the tetramethylene glycol ether-terminated cyclic compound. Tetramethylene glycol ether-terminated cyclic compounds usable in step (2) include those described above. The copolymerization method and conditions in step (2) are also not particularly limited, and conventionally known lactic acid copolymer production methods and conditions may be used. Although not limited thereto, according to one embodiment of the present invention, an initiator and a tetramethylene glycol ether-terminated cyclic compound as described above are added to the resultant mixture (including the catalyst) of step (1), and a nitrogen atmosphere The copolymer may be formed by reacting at an elevated temperature (eg, 100 to 210 ° C, more specifically, 110 to 150 ° C) and a decompression condition under an appropriate time (for example, 0.5 to 4 hours, more specifically 1 to 3 hours). have. The number average molecular weight (Mn) of the obtained polylactic acid copolymer may be, for example, 50,000 to 300,000, but is not limited thereto.

The initiator that may be used in the copolymerization step may be an aliphatic alcohol (eg, linear or branched aliphatic alcohol having 6 to 20 carbon atoms, more specifically 1-dodecanol, 1-octanol, or a mixture thereof). have. The initiator may be used in an amount of 0.0005 to 5 parts by weight, preferably 0.003 to 0.1 parts by weight based on 100 parts by weight of lactic acid, lactic acid oligomer or lactide. If the amount of the initiator is less than 0.0005 parts by weight, there may be a problem in controlling the molecular weight of the copolymer, and if it is more than 5 parts by weight, there may be a problem in the degree of polymerization of the copolymer.

As described above, the polylactic acid copolymer of the present invention is biodegradable and eco-friendly, and at the same time exhibits improved elasticity and thermal stability compared to polylactic acid homopolymers, and thus can be applied to various applications, and particularly high elasticity and thermal stability. It can be used suitably for resin processed products, such as textile products, medical products (such as surgical sutures or medical films) and film materials, and can increase the efficiency of production processing.

Thus, according to another aspect of the present invention, there is provided a resin processed article produced using the polylactic acid copolymer of the present invention.

The method for producing a resin processed product using the polylactic acid copolymer of the present invention is not particularly limited, and the method generally used for processing the copolymer resin can be used as it is or as appropriately modified.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited to these.

[ Example ]

Example 1

An isosorbide solution and a dimethyl terephthalate solution dissolved in an ethylene acetate solvent were placed in a two neck flask equipped with a Deanstrap trap, followed by heating and stirring to the reflux temperature of the ethylene acetate solvent to proceed with the first reaction, followed by polytetramethylene Ether glycol (Poly tetramethylene ether glycol, hereinafter PTMEG) was added to proceed with the secondary reaction. Subsequently, the secondary reactants were removed by washing with an alkaline solution and washing with distilled water, and a tetramethylene glycol ether-terminated cyclic compound of the following Chemical Formula 1-3 was prepared through a solvent removal process under vacuum and reduced pressure.

[Formula 1-3]

In Formula 1-3, n is 1.

(1) Step: Preparation of Lactic Acid Prepolymer

1.2 kg of lactide (Purac, purity 99.7%) was added to a 2 L reactor, and then water was removed for at least 2 hours under vacuum reduced pressure of less than 1 Torr and a temperature of 50 ° C. After the removal of water, the vacuum pressure was released and the initiator and the catalyst were added while gradually raising the temperature under a nitrogen environment, and the lactic acid prepolymer was prepared by stirring at a temperature of 120 ° C. for 2 hours. As the initiator, 0.1 g of 1-dodecanol (Sigma Aldrich) was used, and 6 g of tin (II) octanoate (Sn (Oct) ₂ , Sigma Aldrich) purified on toluene anhydride was used as a catalyst. The number average molecular weight (Mn) of the prepared lactic acid prepolymer was 2,000 to 10,000.

(2) step: Polylactic acid  Copolymer preparation

After stirring the lactic acid prepolymer prepared in step (1) in a nitrogen atmosphere for 2 hours, the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 1-3 36 g was added at a temperature of 180 ° C., followed by copolymerization at a temperature of 200 ° C. The number average molecular weight (Mn) of the polylactic acid copolymer prepared was 50,000 to 300,000. Tetramethylene glycol ether-terminated cyclic compound of Formula 1-3 The content of the repeating unit was 3% by weight based on the total weight of the polylactic acid copolymer prepared.

The NMR spectrum of the polylactic acid copolymer prepared above was measured using a Bruker Avance DRX 300. NMR spectral analysis showed that the position shifted due to the hydroxyl group at the end of the tetramethylene glycol ether-terminal cyclic compound was shifted due to electronic environmental change as the ester group was changed through polylactic acid copolymerization. It can be confirmed that the copolymerization result.

Example 2

Tetramethylene glycol ether-terminated cyclic compound of Formula 1-3 A polylactic acid copolymer was prepared in the same manner as in Example 1, except that the content of the repeating unit was changed to 10% by weight (based on the total weight of the copolymer).

Example 3

A naphthalenedicarboxylate solution and a PTMEG solution dissolved in an ethylene acetate solvent were added to a two neck flask provided with a Deanstock trap, and the reaction was performed by heating and stirring to the reflux temperature of the ethylene acetate solvent. Subsequently, the secondary reactants were removed by washing with an alkaline solution and washing with distilled water, and a tetramethylene glycol ether-terminated cyclic compound of the following Chemical Formula 2-3 was prepared through a solvent removal process under vacuum and reduced pressure.

[Formula 2-3]

In Formula 2-3, n is 2.

(1) Step: Preparation of Lactic Acid Prepolymer

Lactic acid prepolymer was prepared in the same manner as in Example 1.

(2) step: Polylactic acid  Copolymer preparation

After the lactic acid prepolymer prepared in step (1) was stirred for 2 hours in a nitrogen atmosphere, 36 g of the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 2-3 was added at 180 ° C., followed by 200 ° C. Copolymerization was carried out at temperature. The number average molecular weight (Mn) of the polylactic acid copolymer prepared was 50,000 to 300,000. The content of the tetramethylene glycol ether-terminated cyclic compound repeating unit of Formula 2-3 was 3 wt% based on the total weight of the polylactic acid copolymer prepared.

The NMR spectrum of the polylactic acid copolymer prepared above was measured using a Bruker Avance DRX 300. NMR spectral analysis showed that the position shifted due to the hydroxyl group at the end of the tetramethylene glycol ether-terminal cyclic compound was shifted due to electronic environmental change as the ester group was changed through polylactic acid copolymerization. It can be confirmed that the copolymerization result.

Example 4

Polylactic acid copolymer in the same manner as in Example 3, except that the content of the tetramethylene glycol ether-terminated cyclic compound repeating unit of Formula 2-3 was changed to 10% by weight (based on the total weight of the copolymer) Was prepared.

Example 5

A biphenol solution and a dimethyl terephthalate solution dissolved in an ethylene acetate solvent were added to a two neck flask equipped with a Dean Stark trap, and heated and stirred at the reflux temperature of the ethylene acetate solvent to proceed with the first reaction, followed by addition of PTMEG. The secondary reaction was advanced. Subsequently, the secondary reactants were removed by washing with an alkaline solution and washing with distilled water, and a tetramethylene glycol ether-terminated cyclic compound of the following Chemical Formula 2-4 was prepared through a solvent removal process under vacuum and reduced pressure.

[Formula 2-4]

In Formula 2-4, n is 1.

(1) Step: Preparation of Lactic Acid Prepolymer

Lactic acid prepolymer was prepared in the same manner as in Example 1.

(2) step: Polylactic acid  Copolymer preparation

After the lactic acid prepolymer prepared in step (1) was stirred for 2 hours in a nitrogen atmosphere, 36 g of the tetramethylene glycol ether-terminated cyclic compound of Formula 2-4 was added at 180 ° C., followed by 200 ° C. Copolymerization was carried out at temperature. The number average molecular weight (Mn) of the polylactic acid copolymer prepared was 50,000 to 300,000. The content of the tetramethylene glycol ether-terminated cyclic compound repeat unit of Formula 2-4 was 3 wt% based on the total weight of the polylactic acid copolymer prepared.

The NMR spectrum of the polylactic acid copolymer prepared above was measured using a Bruker Avance DRX 300. NMR spectral analysis showed that the position shifted due to the hydroxyl group at the end of the tetramethylene glycol ether-terminal cyclic compound was shifted due to electronic environmental change as the ester group was changed through polylactic acid copolymerization. It can be confirmed that the copolymerization result.

Example 6

Polylactic acid copolymer in the same manner as in Example 5, except that the content of the tetramethylene glycol ether-terminated cyclic compound repeating unit of Formula 2-4 was changed to 10% by weight (based on the total weight of the copolymer) Was prepared.

Example 7

In a 2-neck flask equipped with a Deanstrap trap, a naphthalenediol solution and a dimethyl terephthalate solution dissolved in an ethylene acetate solvent were added, followed by heating and stirring to the reflux temperature of the ethylene acetate solvent to proceed with a primary reaction, followed by addition of PTMEG. The secondary reaction was advanced. Subsequently, the secondary reactants were removed by washing with an alkaline solution and washing with distilled water, and a tetramethylene glycol ether-terminated cyclic compound of the following Chemical Formula 2-5 was prepared through a solvent removal process under vacuum and reduced pressure.

[Formula 2-5]

In Formula 2-5, n is 1.

(1) Step: Preparation of Lactic Acid Prepolymer

Lactic acid prepolymer was prepared in the same manner as in Example 1.

(2) step: Polylactic acid  Copolymer preparation

After stirring the lactic acid prepolymer prepared in step (1) in a nitrogen atmosphere for 2 hours, 36 g of the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 2-5 was added at 180 ° C., and then 200 ° C. Copolymerization was carried out at temperature. The number average molecular weight (Mn) of the polylactic acid copolymer prepared was 50,000 to 300,000. The content of the tetramethylene glycol ether-terminated cyclic compound repeat unit of Formula 2-5 was 3% by weight based on the total weight of the polylactic acid copolymer prepared.

The NMR spectrum of the polylactic acid copolymer prepared above was measured using a Bruker Avance DRX 300. NMR spectral analysis showed that the position shifted due to the hydroxyl group at the end of the tetramethylene glycol ether-terminal cyclic compound was shifted due to electronic environmental change as the ester group was changed through polylactic acid copolymerization. It can be confirmed that the copolymerization result.

Example 8

Polylactic acid copolymer in the same manner as in Example 7, except that the content of the tetramethylene glycol ether-terminated cyclic compound repeating unit of Formula 2-5 was changed to 10% by weight (based on the total weight of the copolymer) Was prepared.

Comparative Example 1

A polylactic acid homopolymer was prepared in the same manner as in Example 1, except that the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 1-3 was not used as the copolymer repeating unit.

Comparative Example 2

The same method as in Example 1, except that isosorbide (content of 3% by weight based on the total weight of the copolymer) was used instead of the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 1-3 as a copolymer repeating unit. Polylactic acid copolymer was prepared.

Comparative Example 3

The same method as Example 1, except that isosorbide (content of 10% by weight based on the total weight of the copolymer) was used instead of the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 1-3 as a copolymer repeating unit. Polylactic acid copolymer was prepared.

[Comparative Example 4]

Instead of the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 1-3, a cyclic compound containing a hydroxy-terminated ester group of Chemical Formula 3 (3 wt% based on the total weight of copolymer) was used as the copolymer repeating unit. Except for producing a polylactic acid copolymer in the same manner as in Example 1.

[Formula 3]

[Comparative Example 5]

Instead of the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 1-3, a cyclic compound containing a hydroxy-terminated ester group of Chemical Formula 3 (5 wt% based on the total weight of copolymer) was used as a copolymer repeating unit. Except for producing a polylactic acid copolymer in the same manner as in Example 1.

Comparative Example 6

Instead of the tetramethylene glycol ether-terminated cyclic compound of Chemical Formula 1-3, a cyclic compound containing a hydroxy-terminated ester group of Chemical Formula 3 (7 wt% based on the total weight of copolymer) was used as a copolymer repeating unit. Except for producing a polylactic acid copolymer in the same manner as in Example 1.

<Measurement of properties>

For the polylactic acid homopolymer and the polylactic acid copolymer prepared according to the Examples and Comparative Examples, the properties of the following items were measured and determined according to their own criteria, and the results are shown in Table 1 below.

(1) Glass transition temperature (Tg) and glass transition temperature increase rate (△ Tg)

Perkin Elmer's Diamond DSC (Differential Scanning Calorimetry) was used to measure the glass transition temperature of the polylactic acid homopolymer and polylactic acid copolymer, and based on the glass transition temperature of the polylactic acid homopolymer (Comparative Example 1), The rate of glass transition temperature rise was calculated.

(2) Initial Modulus (G ') and Initial Modulus Reduction (ΔG')

The initial modulus (storage modulus) of the polylactic acid homopolymer and the polylactic acid copolymer was measured using a Pysis diamond DMA (Dynamic Mechanical Analyzer) manufactured by Perkin Elmer at a frequency of 1 Hz in the temperature range of 30 to 150 ° C. The initial modulus reduction rate of the polylactic acid copolymer was calculated based on the initial modulus of Comparative Example 1).

(3) Judging standard

As compared with the glass transition temperature and initial modulus of the polylactic acid homopolymer (Comparative Example 1), the glass transition temperature rise rate and initial modulus reduction rate of each copolymer were measured as follows.

○: Meets both glass transition temperature increase rate of 5% or more and initial modulus decrease rate of 5% or more

×: One or more of glass transition temperature increase rate of 5% or more and initial modulus decrease rate of 5% or more are not satisfied

TABLE 1

Claims (16)

1. As a repeating unit

   (A) lactic acid; And

   Comprising (B) a monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at the terminal;

   Polylactic acid copolymer.
2. The polylactic acid copolymer according to claim 1, wherein the lactic acid repeating unit is introduced into the copolymer by lactic acid, lactic acid oligomer or lactide.
3. The polylactic acid copolymer according to claim 1, wherein the monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at the terminal has a structure represented by the following Chemical Formula 1-1. :

   [Formula 1-1]

   HO- (CH ₂ ) _4- (OR ₁ ) -BA-B '-(R ₂ -O)-(CH ₂ ) ₄ -OH

   In Chemical Formula 1-1,

   R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group, wherein R ₁ and R ₂ each independently comprise one or more bonds selected from ether bonds, ester bonds, ketone bonds and urethane bonds Can do it,

   B and B 'each independently represent an anhydrosugar alcohol, the anhydrosugar alcohol may be in the form of substituted or unsubstituted alkylene glycol at one or both ends thereof,

   A is a substituted or unsubstituted divalent aliphatic or aromatic monocyclic, polycyclic or fused cyclic group; Or a substituted or unsubstituted divalent monoheterocyclic, polyheterocyclic or fused heterocyclic group comprising at least one hetero atom selected from N, O and S, wherein A is an ester group, an ether group, It may comprise one or more functional groups selected from the group consisting of thioether groups, ketone groups and urethane groups.
4. The method of claim 3, wherein in Chemical Formula 1-1,

   R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group having 12 to 328 carbon atoms, wherein R ₁ and R ₂ are each independently from an ether bond, an ester bond, a ketone bond and a urethane bond May comprise one or more combinations selected,

   B and B 'each independently represent dianhydrohexitol, and the dianhydrohexitol may be substituted or unsubstituted with alkylene glycol at one or both ends thereof.

   A is a substituted or unsubstituted divalent, aliphatic having 5 to 30 carbon atoms or an aromatic monocyclic, polycyclic or fused cyclic group having 6 to 30 carbon atoms; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having at least 5 to 30 ring atoms, comprising at least one hetero atom selected from N, O and S, A may also comprise one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups,

   Polylactic acid copolymer.
5. The method of claim 3, wherein in Chemical Formula 1-1,

   R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group having 12 to 248 carbon atoms, wherein R ₁ and R ₂ are each independently from an ether bond, an ester bond, a ketone bond and a urethane bond May comprise one or more combinations selected,

   B and B 'each independently represent dianhydrohexitol, and the dianhydrohexitol may be substituted or unsubstituted with alkylene glycol at one or both ends thereof.

   A is a substituted or unsubstituted divalent, aromatic monocyclic, polycyclic or fused cyclic group having 6 to 20 carbon atoms in total; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having at least 5 to 20 ring atoms, and at least one hetero atom selected from N, O and S, A may also include one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups,

   Polylactic acid copolymer.
6. The polylactic acid copolymer according to claim 1, wherein the monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at the terminal has a structure represented by the following Chemical Formula 2-1. :

   [Formula 2-1]

   HO- (CH ₂ ) _4- (OR ₁ ) -A- (R ₂ -O)-(CH ₂ ) ₄ -OH

   In Chemical Formula 2-1,

   R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group, wherein R ₁ and R ₂ each independently comprise one or more bonds selected from ether bonds, ester bonds, ketone bonds and urethane bonds Can do it,

   A is a substituted or unsubstituted divalent aliphatic or aromatic monocyclic, polycyclic or fused cyclic group; Or a substituted or unsubstituted divalent monoheterocyclic, polyheterocyclic or fused heterocyclic group comprising at least one hetero atom selected from N, O and S, wherein A is an ester group, an ether group, It may comprise one or more functional groups selected from the group consisting of thioether groups, ketone groups and urethane groups.
7. The method of claim 6, wherein in Chemical Formula 2-1,

   R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group having 12 to 328 carbon atoms, wherein R ₁ and R ₂ are each independently from an ether bond, an ester bond, a ketone bond and a urethane bond May comprise one or more combinations selected,

   A is a substituted or unsubstituted divalent, aliphatic having 5 to 30 carbon atoms or an aromatic monocyclic, polycyclic or fused cyclic group having 6 to 30 carbon atoms; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having at least 5 to 30 ring atoms, comprising at least one hetero atom selected from N, O and S, A may also comprise one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups,

   Polylactic acid copolymer.
8. The method of claim 6, wherein in Chemical Formula 2-1,

   R ₁ and R ₂ each independently represent a substituted or unsubstituted divalent hydrocarbon group having 12 to 248 carbon atoms, wherein R ₁ and R ₂ are each independently from an ether bond, an ester bond, a ketone bond and a urethane bond May comprise one or more combinations selected,

   A is a substituted or unsubstituted divalent, aromatic monocyclic, polycyclic or fused cyclic group having 6 to 20 carbon atoms in total; Or a substituted or unsubstituted divalent, monoheterocyclic, polyheterocyclic or fused heterocyclic group having at least 5 to 20 ring atoms, and at least one hetero atom selected from N, O and S, A may also comprise one or more functional groups selected from the group consisting of ester groups, ether groups, thioether groups, ketone groups and urethane groups,

   Polylactic acid copolymer.
9. The compound according to claim 1, wherein the monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at its terminal is represented by the following formula 1-3, represented by the following formula 2-3 A polylactic acid copolymer selected from the group consisting of a compound, a compound represented by the following Chemical Formula 2-4, and a compound represented by the following Chemical Formula 2-5:

   [Formula 1-3]

   

   [Formula 2-3]

   

   [Formula 2-4]

   

   [Formula 2-5]

   

   In Formula 1-3, n represents an integer of 1 to 80,

   In Chemical Formula 2-3, n represents an integer of 2 to 80,

   In Formula 2-4, n represents an integer of 1 to 80,

   In Formula 2-5, n represents an integer of 1 to 80.
10. (1) prepolymerizing lactic acid, lactic acid oligomers or lactide; And

    (2) copolymerizing the lactic acid prepolymer obtained in step (1) with a monocyclic, polycyclic or fused cyclic compound having a hydroxy-tetramethylene-oxy-hydrocarbon group at the terminal;

    Method for producing a polylactic acid copolymer.
11. The method for preparing a polylactic acid copolymer according to claim 10, wherein the prepolymerization of step (1) is performed in the presence of a catalyst.
12. 12. The catalyst according to claim 11, wherein the catalyst is zinc oxide, antimony oxide, antimony chloride, lead oxide, calcium oxide, aluminum oxide, iron oxide, calcium chloride, zinc acetate, paratoluene sulfonic acid, first tin chloride, first tin sulfate, oxidizing agent 1 tin, a second tin oxide, a first tin octanoate, tetraphenyl tin, tin powder, titanium tetrachloride or a mixture thereof.
13. The method for producing a polylactic acid copolymer according to claim 10, wherein the copolymerization of step (2) is performed in the presence of an initiator.
14. The method for producing a polylactic acid copolymer according to claim 13, wherein the initiator is an aliphatic alcohol.
15. The resin processed product manufactured using the polylactic acid copolymer of any one of Claims 1-9.
16. The resin processed product of Claim 15 which is a fiber or a film.