KR20110024610A - Organometallic catalysts for the preparation of polylactide resin, preparation method thereof, and polylactide resin prepared therefrom - Google Patents

Abstract

PURPOSE: An organometallic catalyst is provided to prepare a polylactide resin of high molecular weight in high yield without use of initiators. CONSTITUTION: An organometallic catalyst for preparing a polylactide resin is represented by chemical formula 1: R1O-Sn-OR2. In chemical formula 1, R1 and R2 are respectively C5-30 primary, secondary, or tertiary alkyl group. A method for preparing the polylactide resin comprises a step for ring-opening and polymerizing a lactide monomer in the presence of the organometallic catalyst represented by chemical formula 1.

Description

Organometallic catalysts for preparing polylactide resins, methods for preparing polylactide resins using the organometallic catalysts, and polylactide resins prepared thereby Therefrom}

The present invention relates to an organometallic catalyst for producing polylactide resin, a method for producing polylactide resin using the organometallic catalyst, and a polylactide resin produced thereby.

Polylactide (or polylactic acid) resin is a kind of resin containing a repeating unit of the following general formula. Such polylactide resin because it is based on biomass (biomass) Unlike conventional oil-based resin, can take advantage of renewable resources, and global warming gases such as CO ₂ emissions reduced compared to conventional resin during production In addition, it is an environmentally friendly material, such as biodegradation by water and microorganisms in landfills, and has a suitable mechanical strength comparable to conventional crude oil-based resins.

[General Formula]

These polylactide resins have been mainly used for disposable packaging / containers, coatings, foams, films / sheets, and textiles. Recently, polylactide resins have been mixed with existing resins such as ABS, polycarbonate, or polypropylene. After reinforcement, efforts to use semi-permanent uses such as mobile phone exterior materials or automobile interior materials have been actively made. However, polylactide resins are currently limited in their application range due to physical weaknesses of polylactide itself, such as biodegradation by the catalyst used in manufacturing or by factors such as moisture in the air.

On the other hand, as a previously known method for producing a polylactide resin, a method of directly polycondensing lactic acid or a ring opening polymerization of a lactide monomer under an organometallic catalyst is known. Among these methods, direct polycondensation can produce inexpensive polymers, but since it is difficult to obtain a polymer having a high molecular weight of 100,000 or more by weight average molecular weight, it is difficult to sufficiently secure the physical and mechanical properties of the polylactide resin. In addition, the ring-opening polymerization method of the lactide monomer is required to produce the lactide monomer from lactic acid, which requires a higher cost than the polycondensation polymerization. However, a relatively large molecular weight resin can be obtained and the polymerization control is advantageously applied commercially.

On the other hand, Lewis acid is used as the organometallic catalyst used for the ring-opening polymerization of lactide, and Sn-catalyst such as tin (II) 2-ethylhexanoate (hereinafter, Sn- (Oct) ₂ ) is used. In the ring-opening polymerization, the Sn-catalyst is added together with alcohols as an initiator, activated by Sn- (OR) ₂ form by the initiator, and then the polymerization proceeds (Kowalski et. Al., Macromolecules , 2000, 33, 7359). -7370). In particular, Sn- (Oct) ₂ reacts with an alcohol initiator to produce octanoic acid, which is converted into the active species form of tin (monoalkoxide) or tin (dialkoxide).

On the other hand, when the polymerization reaction in the presence of the catalyst of Sn (Oct) ₂ as described above, a chain transfer reaction occurs by water, alcohol, acid, etc., if the chain transfer reaction by acid, polymerization There is a problem that the reaction is stopped or the activated catalyst is returned to the inactive form of Sn- (Oct) ₂ . Therefore, a problem arises in that the molecular weight of the polylactide to be polymerized becomes small and the polymerization reaction rate becomes slow.

Due to the above-mentioned disadvantages, it is difficult to provide polylactide resins having a sufficiently large molecular weight in high yield due to depolymerization, etc., even if the previously known ring-opening polymerization reaction is applied, and furthermore, residual monomers during the use of the polylactide resins. Or it is true that polylactide resin decomposed | disassembled by the catalyst etc., and hydrolysis resistance or heat resistance was not enough. In order to solve this problem, a method of using a Zn-containing catalyst instead of Sn has been considered, but in this case, there is a disadvantage in low polymerization activity (Nijenhuis et al. Macromolecules 1992, 25, 6419-6424). Due to these problems, efforts to use polylactide resin for semi-permanent use such as mobile phone exterior materials or automotive interior materials are facing limitations.

Accordingly, the present invention is to provide a novel organometallic catalyst for producing a polylactide resin that can obtain a high yield of polylactide in high yield.

In addition, the present invention is to provide a method for producing a polylactide resin comprising the ring-opening polymerization of the lactide monomer in the presence of the novel organometallic catalyst.

The present invention is also to provide a high molecular weight polylactide resin and a polylactide resin composition comprising the same produced by the above method.

The present invention provides an organometallic catalyst for producing polylactide resin by ring-opening polymerization reaction of a lactide monomer represented by the following formula (1).

[Formula 1]

R ₁ O-Sn-OR ₂

In Formula 1, R ₁ and R ₂ are each independently a primary, secondary, or tertiary alkyl group having 5 to 30 carbon atoms.

In addition, the present invention provides a method for producing a polylactide resin comprising the step of ring-opening polymerization of the lactide monomer in the presence of the organometallic catalyst represented by the formula (1).

The present invention also provides a polylactide resin and a polylactide resin composition comprising the same.

Hereinafter, an organometallic catalyst for preparing a polylactide resin, a method for preparing a polylactide resin using the organometallic catalyst, and a polylactide resin produced by the same will be described.

Unless otherwise expressly stated, some terms used throughout this specification are defined as follows.

Unless specifically stated throughout this specification, the term "comprise" or "contains" means including any component (or component) without particular limitation, and excluding the addition of other components (or components). Cannot be interpreted as.

In addition, throughout the present specification, the 'lactide monomer' may be defined as follows. Lactide can be generally classified into L-lactide composed of L-lactic acid, D-lactide composed of D-lactic acid, and meso-lactide composed of one L-form and one D-form. In addition, the mixture of L-lactide and D-lactide in 50:50 is called D, L-lactide or rac-lactide. Among these lactides, polymerization using only L-lactide or D-lactide with high optical purity is known to yield L- or D-polylactide (PLLA or PDLA) having very high stereoregularity. Lactide is known to have higher crystallization rate and higher crystallization rate than polylactide having low optical purity. However, the term "lactide monomer" herein is defined to include all types of lactide regardless of the difference in the properties of the lactide according to each form and the difference in the properties of the polylactide formed therefrom.

In addition, throughout this specification, the term "polylactide resin" is defined as a generic term referring to a homopolymer or copolymer including repeat units of the following general formula. Such a 'polylactide resin' may be prepared by the step of forming the following repeating unit by the ring-opening polymerization of the above-described 'lactide monomer', the polymer after the ring-opening polymerization and the formation process of the following repeating unit is completed It may be referred to as the 'polylactide resin'. At this time, the category of 'lactide monomer' includes all types of lactide as described above.

[General Formula]

The category of the polymer which may be referred to as the 'polylactide resin' includes polymers in all states after the ring-opening polymerization and the formation of the repeating unit are completed, for example, a crude or purified state after the ring-opening polymerization is completed. The polymer of the polymer, the polymer contained in the liquid or solid resin composition before the molding of the product, or the polymer contained in the plastic or fabric, etc., the product molding is completed may be all included. Thus, throughout this specification, the physical properties (acidity, weight average molecular weight or residual catalyst amount, etc.) of the 'polylactide resin' are defined as the physical properties of the polymer in any state after the ring-opening polymerization and the formation of the repeating unit are completed. Can be.

In addition, throughout the present specification, the term 'polylactide resin composition' includes or is prepared from the 'polylactide resin' and is defined as referring to any composition before or after molding a product. The category of the composition which may be referred to as the 'polylactide resin composition' may include not only liquid or solid resin compositions exhibiting a state of master batch or pellets before molding, but also plastic or fabric after molding of the product. have.

On the other hand, the present inventors were able to synthesize a polylactide resin in a higher yield than in the reaction for producing a polylactide resin using a conventional catalyst through a production method described below using a specific catalyst, It was found that a high molecular weight polylactide resin can be produced in high yield without using, and completed the invention.

An organometallic catalyst for preparing a polylactide resin by a ring-opening polymerization reaction of a lactide monomer according to an embodiment of the present invention is represented by the following Chemical Formula 1.

[Formula 1]

R ₁ O-Sn-OR ₂

In Formula 1, R ₁ and R ₂ are each independently a primary, secondary, or tertiary alkyl group having 5 to 30 carbon atoms.

In general, when the organotin compound is used as a catalyst for the polymer polymerization reaction, it is used together with a separate initiator, and participates in the polymerization reaction in an activated state by the initiator added together to promote the reaction rate. Therefore, when the catalyst is present in an activated state, it is not necessary to use a separate initiator during the polymerization reaction, and an initial time for activating the catalyst is not necessary, and thus a faster initial polymerization rate can be expected.

The organometallic catalyst as described above has a chemical structure of R ₁ O-Sn-OR ₂ , and has a structure of an activated catalyst, and thus does not require a separate initiator in the polymerization reaction, and also in the polymerization reaction. No acid is produced. Therefore, in the case of polymerization using a conventional Sn- (Oct) ₂ catalyst or the like, the problem of lowering the polymerization reaction rate and lowering the molecular weight of the synthesized polylactide due to the chain transfer reaction by the acid generated during the polymerization can be solved. Can be. Therefore, when the ring-opening polymerization reaction of the lactide monomer is carried out in the presence of the organometallic catalyst as described above, it was observed that the polymerization yield is high and the molecular weight of the polylactide to be polymerized is also large.

In particular, in the case of the organometallic catalysts according to an embodiment of the present invention including an alkoxy group having 5 or more carbon atoms, the steric hindrance phenomenon occurring when present in the form of 2 coordination to 4 coordination is increased as the number of carbon atoms increases. The structure of the form in which the phosphorus-OR substituent is exposed to the outside increases (FIG. 3), and thus the polymerization yield is higher in the polymerization reaction than in the case of using a tin (II) alkoxide having less than 5 carbon atoms as a catalyst. It was found that the molecular weight of the polymer was also large.

Meanwhile, in Formula 1, R ₁ and R ₂ may be each independently, and may be selected without limitation in configuration if they are primary, secondary, or tertiary alkyl groups having 5 to 30 carbon atoms. In consideration of ease of manufacture, etc., R ₁ and R ₂ of Formula 1 may be each independently C ₆ H ₁₃ , C ₈ H ₁₇ , or C ₁₂ H ₂₅ . More preferably, the organometallic catalyst may be Sn (O (CH ₂ ) ₅ CH ₃ ) ₂ , Sn (O (CH ₂ ) ₇ CH ₃ ) ₂ , or Sn (O (CH ₂ ) ₁₁ CH ₃ ) _2. have.

When the ring-opening polymerization reaction of the lactide monomer is carried out in the presence of the above-mentioned tin (II) alkoxide catalyst having 5 or more carbon atoms, the polymerization yield is high, and no acid is formed during the polymerization, so that the chain transfer reaction with acid and The molecular weight decrease phenomenon of the synthesized polymer according to this does not appear.

On the other hand, the organometallic catalyst as described above is not limited in its configuration, but reacting Sn (II) salt and methanol to form Sn (OCH ₃ ) ₂ ; And reacting the Sn (OCH ₃ ) ₂ with a primary, secondary, or tertiary alcohol having 5 to 30 carbon atoms to form an organometallic catalyst represented by Chemical Formula 1. have. In this case, the Sn (II) salt may be SnCl ₂ , SnBr ₂ , SnI ₂ , or SnSO ₄ , and the alcohol may be hexanol, octanol, dodecanol, or the like, but is not limited to the above-described example.

On the other hand, the present invention provides a method for producing a polylactide resin using the above-described organometallic catalyst according to another embodiment. Specifically, the preparation method includes the step of ring-opening polymerization of the lactide monomer in the presence of the organometallic catalyst represented by the formula (1). As described above, when the ring-opening polymerization reaction of the lactide monomer is performed using the organometallic catalyst represented by Chemical Formula 1, no acid is generated separately during polymerization, and thus the polymerization reaction rate is slowed or the molecular weight of the polymer to be polymerized is increased. There is no fear of lowering, there is an advantage that can be obtained in high yield of a high molecular weight polylactide.

In particular, by using the organometallic catalyst according to an embodiment of the present invention including an alkoxy group having 5 or more carbon atoms as described above, after the synthesis of the compound, the steric hindrance that occurs when the organotin compound is present in the coordination form 2 to 4 coordination ( The steric hindrance phenomenon was largely increased as the number of carbon atoms increased, and the structure of the form in which the active species-OR substituent was exposed to the outside was increased (FIG. 3), resulting in polymerization yield compared to tin (II) alkoxide having less than 5 carbon atoms. This is high and the molecular weight of the polymer to be polymerized is also large.

At this time, the addition amount of the organometallic catalyst is not limited in its configuration, but may preferably be added in a ratio of 0.001 to 1.0 mole to 100 moles of lactide monomer. If the addition ratio of such a catalyst is too small, the polymerization activity is not sufficient, and if the addition ratio of the catalyst is too large, on the contrary, if the addition ratio of the catalyst is too large, the amount of residual catalyst of the produced polylactide resin becomes large, resulting in decomposition or reduction of the molecular weight of the resin during processing and the resin. May cause discoloration, etc.

On the other hand, the catalyst used in the polylactide production method as described above may be selected without limitation in the composition as long as it is a tin (II) alkoxide catalyst having the formula represented by the formula (1), preferably Sn (O ( CH ₂ ) ₅ CH ₃ ) ₂ , Sn (O (CH ₂ ) ₇ CH ₃ ) ₂ , or Sn (O (CH ₂ ) ₁₁ CH ₃ ) ₂ catalyst may be used. The tin (II) alkoxide as described above is easy to manufacture and handle, and especially in the production of polylactide, the polymerization yield is high.

The ring-opening polymerization reaction of the lactide monomer may be carried out by bulk polymerization or solution phase polymerization. In the polylactide preparation according to the above-described embodiments, both bulk polymerization and solution phase polymerization may be used. It is possible.

Here, bulk polymerization may be defined as a polymerization reaction that is substantially free of solvent, and substantially no solvent is used per small amount of solvent for dissolving the catalyst, for example, 1 kg of lactide monomer used. Up to 1 ml of solvent may be used. When the ring-opening polymerization is carried out in bulk polymerization, the step for removing the solvent after the polymerization can be omitted, and the decomposition or loss of the resin in the solvent removing step can also be suppressed.

On the other hand, when the solution phase polymerization, as a solvent that can be used as long as it can dissolve the lactide monomer and the organometallic catalyst can be used without limitation of the configuration. Specifically, toluene, xylene, chloroform, dimethyl chloride, diphenyl, or a mixture of two or more of the above-described solvents may be used, but is not limited thereto. In the case of solution phase polymerization, when the polymerization reaction proceeds, the viscosity of the polymerization liquid can be kept low, which is advantageous for mixing, and is advantageous in that polymerization water transfer is easy .

On the other hand, the lactide monomer may be prepared from lactic acid. Such lactide monomers can also be any form of lactide, including any form of lactide, including L, L-lactide, D, L-lactide or D, D-lactide, etc. .

The ring-opening polymerization of the lactide monomer may be performed at a temperature of 120 to 220 ° C. On the other hand, in the above temperature conditions, the polymerization reaction may proceed for 0.5 to 48.0 hours, preferably 1.0 to 10.0 hours, but is not limited to the above time. In the above-described manufacturing method, by using a catalyst having excellent activity, a polylactide resin having a higher molecular weight than previously known can be obtained with high conversion and yield, and no acid is generated during polymerization, so that depolymerization or decomposition of the resin It is also desirable as it can be reduced.

On the other hand, according to another embodiment of the invention there is provided a polylactide resin prepared by the above-described manufacturing method. The polylactide resin prepared by the above production method has a high molecular weight, specifically, a weight average molecular weight of 100,000 to 1,000,000. In addition, the polylactide resin prepared with the above catalyst has an acidity of less than 50 meq / kg, preferably an acidity of less than 30 meq / kg, and most preferably an acidity of less than 10 meq / kg.

On the other hand, according to another embodiment of the invention is provided a polylactide resin composition comprising the polylactide resin described above.

Since the polylactide resin composition includes a high molecular weight polylactide resin, the polylactide resin composition is expected to exhibit excellent physical and mechanical properties, and thus may be preferably used for semi-permanent use such as electronics packaging or automotive interior materials.

In addition, since the polylactide resin composition includes a biodegradable polylactide resin, the polylactide resin composition may be used in the manufacture of a biodegradable container such as a disposable container, a disposable fork or a disposable product.

In this case, the polylactide resin composition may include polylactide resin alone or may include polycarbonate resin, ABS resin, or polypropylene resin. However, when used for electronic electronics packaging or automotive interior materials, the polylactide resin composition is not limited in its constitution, but in consideration of deterioration of mechanical properties such as durability, the polylactide resin is preferably 50 wt%. It may comprise less than%. In addition, when used in the manufacture of products that require more biodegradability, such as disposable products, the composition is not limited, but the composition may comprise at least 60% by weight of polylactide resin, more preferably at least 80% by weight of polylactide resin. It may include.

In addition, the polylactide resin composition may further include various additives previously included in various resin compositions.

The polylactide resin composition may be a liquid or solid resin composition before molding the final product, or may be a plastic or a fabric in a final product state, and the final plastic or textile product may be a conventional method according to each product type. It can be prepared by.

As described above, according to the present invention, an organometallic catalyst capable of producing a high molecular weight polylactide resin at high yield without using an initiator, and a method for producing polylactide using the same can be provided.

Therefore, the present invention can produce a high molecular weight polylactide resin in an economical manner, and can be usefully used in the industrial field relating to the production of polylactide resins.

Hereinafter, the operation and effects of the invention will be described in more detail with reference to specific examples of the invention. However, these embodiments are only presented as an example of the invention, whereby the scope of the invention is not determined.

[ Synthetic example : Tin ( II ) alkoxide Synthesis of

1. Experimental Method

The following experimental manipulations were performed under nitrogen gas using the Schlenk technique using a glove box and a vacuum manifold. Oxygen in the nitrogen gas was a copper catalyst and moisture was removed by Drierite (CuSO ₄ , Aldrich). Methanol (MeOH), toluene (PhMe) and diethyl ether (Et ₂ O) were used as an anhydrous solvent purchased from Aldrich. All solvents were purified through an alumina column, dried over molecular sieve (4A) and degassed prior to use.

Tin (II) chloride, triethylamine, 1-butanol, 1-hexanol and 1-octanol were produced by Aldrich. , 1-dodecanol was purchased from TCI and used immediately without any purification. C6D6 was purchased from Cambridge Isotope Laboratories, Inc., dried over molecular sieves (4A), and then vacuum distilled.

¹ H, ¹³ C, ¹¹⁹ Sn spectra were recorded at 70 ° C. for each solvent using a Bruker AVANCE 400.13 MHz NMR spectrometer spectrometer. Elemental analysis (EA) was measured with an EA 1110-FISONS (CE) elemental analyzer.

2. Tin  ( II ) alkoxide Synthesis of

The synthesis of tin (II) alkoxide compounds was accomplished in two steps. The first step is to synthesize Sn (OCH ₃ ) ₂ from SnCl ₂ using a base in a methanol solvent. 2.01 g (10.6 mmol) of SnCl ₂ was dissolved in 100 mL of anhydrous methanol, and excess triethylamine (3.25 mL, 23.3 mmol) was slowly added to the stirred methanol solution through a syringe. After confirming that a white permanent precipitate was formed, the mixture was stirred for about 3 hours at room temperature. The white precipitate was filtered off, washed with anhydrous methanol and anhydrous diethyl ether, and dried in vacuo. The obtained Sn (OCH ₃ ) ₂ was stored under nitrogen.

The second step is the synthesis of tin (II) alkoxide compounds by adding various alcohols to Sn (OCH ₃ ) ₂ . This process is accomplished by transesterification between Sn (OCH ₃ ) ₂ and the primary alcohol.

100 mL of anhydrous toluene was added to Sn (OCH ₃ ) ₂ (1.01 g, 5.59 mmol) obtained in the above procedure, and then an excess of anhydrous primary alcohol (12.3 mmol) was added through a syringe. In this case, 1-butanol for the synthesis of tin (II) butoxide, 1-hexanol for the synthesis of tin (II) hexoxide, 1-octanol for the synthesis of tin (II) octoxide, and tin (II). 1-dodecanol was used to synthesize dodecoxide.

The resulting slurry was refluxed at about 130 ° C. for 12 hours until strong Sn was removed to give a clear solution of white Sn (OCH ₃ ) ₂ . The clear toluene solution was cooled very slowly to room temperature to obtain a white crystalline tin (II) alkoxide compound. The white crystalline solid obtained was filtered off, dried in vacuo and stored under nitrogen.

According to the method as described above, tin (II) butoxide, tin (II) hexoxide, tin (II) octoxide, tin (II) dodecoxide were synthesized.

3. Above In the synthesis example  Synthesized tin (Ⅱ) alkoxide  Confirm

Sn (OCH ₂ CH ₂ CH ₂ CH ₃ ) ₂ [tin (II) butoxide] and three novel tin (II) alkoxide compounds according to the same method, namely Sn (n = 3, 5, 9) OCH ₂ CH ₂ (CH ₂ ) _n CH ₃ ) ₂ was synthesized. The synthesized compound was confirmed by ¹ H, ¹³ C, ¹¹⁹ Sn NMR spectrum and elemental analysis. The elemental analysis results are shown in Table 1, and ¹ H, ¹³ C, and ¹¹⁹ Sn NMR spectra of these tin (II) alkoxide compounds are shown in FIGS. 1 to 3.

Elemental Analysis of Organometallic Tin Compounds compound constitutional formula Calculated Value Analysis value C H C H tin (Ⅱ) butoxide Sn (O (CH ₂ ) ₃ CH ₃ ) ₂ 36.27 6.85 35.81 6.95 tin (Ⅱ) hexoxide Sn (O (CH ₂ ) ₅ CH ₃ ) ₂ 44.89 8.16 44.57 7.92 tin (Ⅱ) octoxide Sn (O (CH ₂ ) ₇ CH ₃ ) ₂ 50.95 9.09 50.71 8.90 tin (Ⅱ) dodecoxide Sn (O (CH ₂ ) ₁₁ CH ₃ ) ₂ 58.90 10.30 58.96 10.22

As shown in Table 1 and Figures 1 to 3, it was confirmed that the pure form of the tin (II) alkoxide compound.

Tin (II) butoxide, Sn (OCH ₂ (CH ₂ ) ₂ CH ₃ ) ₂ . Yield 58.2%. Anal. Calcd for C ₈ H ₁₈ O ₂ Sn: C, 36.27; H, 6.85. Found: C, 35.81; H, 6.95. 1 H NMR (C6D6, 70 ° C.): δ 4.10 (brs, 4H, OCH ₂ ), 3.68 (brs), 1.75 (brs, CH ₂ ), 1.44 (q, J = 20.0, 4H, CH ₂ ), 0.96 (t , 4H, J = 16.0, CH ₃ ). 13 C NMR (C 6 D 6, 70 ° C.): δ 63.22, 37.76, 19.90, 14.14. 119Sn NMR (C 6 D 6, 70 ° C.): δ -139.20, -250.74, -277.98, -303.64 (br).

Tin (II) hexoxide, Sn (OCH ₂ (CH ₂ ) ₄ CH ₃ ) ₂ . Yield 61.1%. Anal. Calcd for C ₁₂ H ₂₆ O ₂ Sn: C, 44.89; H, 8.16. Found: C, 44.57; H, 7.92. 1 H NMR (C 6 D 6, 70 ° C.): δ 4.17 (brs, 4H, OCH ₂ ), 3.99 (brs), 3.82 (t), 1.82 (brs, 4H, CH ₂ ), 1.38 (brs, 12H, CH 2), 0.92 (brs, 6H, CH 3). 13 C NMR (C 6 D 6, 70 ° C.): δ 63.65, 35.71, 32.40, 26.56, 23.08, 14.08. 119 Sn NMR (C 6 D 6, 70 ° C.): δ -139.78, -251.46, -278.23, -307.81 (br).

Tin (II) octoxide, Sn (OCH ₂ (CH ₂ ) ₆ CH ₃ ) ₂ . Yield 50.8%. Anal. Calcd for C ₁₆ H ₃₄ O ₂ Sn: C, 50.95; H, 9.09. Found: C, 50.71; H, 8.90. 1 H NMR (C 6 D 6): δ 4.15 (brs, 4H, OCH ₂ ), 1.82 (brs), 1.40 (brs, 20H, CH ₂ ), 0.90 (brs, 6H, CH ₃ ). 13 C NMR (C 6 D 6, 70 ° C.): δ 63.66, 35.72, 32.29, 30.21, 29.85, 26.96, 22.98, 14.10. 119 Sn NMR (C 6 D 6, 70 ° C.): δ -251.44, -278.09, -311.85 (br).

Tin (II) dodecoxide, Sn (OCH ₂ (CH ₂ ) ₁₀ CH ₃ ) ₂ yield 67.5%. Anal. Calcd for C ₂₄ H ₅₀ O ₂ Sn: C, 58.90; H, 10.30. Found: C, 58.96; H, 10.22. 1 H NMR (C6D6, 70 ° C.): δ 4.14 (brs, 4H, OCH ₂ ), 1.81 (brs), 1.42 (brs, 8H, CH ₂ ), 1.29 (brs, 32H, CH ₂ ), 0.88 (brs, 6H , CH ₃ ). 13 C NMR (C 6 D 6, 70 ° C.): δ 63.65, 35.76, 32.33, 30.35, 30.21, 30.12, 29.77, 27.05, 23.00, 14.16. 119 Sn NMR (C 6 D 6, 70 ° C.): δ -251.67, -278.33, -305.51 (br).

[ Experimental Example : Synthetic tin  ( II ) alkoxide  In the presence of a catalyst Polylactide  Produce]

1. Experimental method

The molecular weight and molecular weight distribution of the polymer were measured using gel permeation chromatography (GPC). The sample was dissolved in chloroform, filtered with a 0.45 μm syringe filter, injected into the device, and measured using a Polymer Lab Mixed C & C column and a refractive index detector (RI detector, Waters 2414 RI). At this time, polystryrene samples were used as a standard. The lactide monomer purity was 99.5%, and the tin (II) alkoxide catalyst was synthesized in the above synthesis example, Sn- (Oct) ₂ catalyst was purchased from Aldrich, and toluene was distilled and purified in potassium / benzophenone. Was used.

2. Example  One: Tin (Ⅱ) hexoxide  With catalyst Polylactide  polymerization

Lactide monomer (2 g, 13.8 mmol), tin (II) hexoxide, (hereinafter Sn- (OHx) ₂ ), and (0.11 wt% toluene solution, 0.1 mL) were added to six 30 mL vials, respectively, for 12 hours under vacuum. It was left to stand. Thereafter, the reaction was carried out at 180 ° C. for 2 hours, and the vial reaction was stopped for a predetermined time, and polymerization yield and molecular weight were measured by ¹ H NMR spectroscopy and GPC. The polymerization results are shown in Table 2 below.

Polymerization time (h) yield(%) Mw (e ^-3 g / mol) PDI (M _w / M _n ) 0.25 24 109 1.22 0.5 42 180 1.40 0.75 53 250 1.65 One 65 335 1.80 2 82 410 2.04

3. Example  2 : Tin (Ⅱ) octoxide  With catalyst Polylactide  polymerization

Lactide monomer (2 g, 13.8 mmol), tin (II) octoxide, (hereinafter Sn (OOc) ₂ ), and (0.13 wt% toluene solution, 0.1 mL) were added to six 30 mL vials, respectively, for about 12 hours under vacuum. It was left to stand. Thereafter, the reaction was performed at 180 ° C. for 2 hours, and the vial reaction was stopped for a predetermined time, and the polymerization yield and molecular weight were measured by ¹ H NMR spectroscopy and GPC. The polymerization results are shown in Table 3.

Polymerization time (h) yield(%) Mw (e ^-3 g / mol) PDI (M _w / M _n ) 0.25 28 120 1.18 0.5 47 220 1.28 0.75 64 312 1.55 One 73 370 1.82 2 86 435 2.09

4. Example  3: tin (Ⅱ) dodecoxide  With catalyst Polylactide  polymerization

Lactide monomer (2 g, 13.8 mmol), tin (II) dodecoxide (hereafter, Sn (ODd) ₂ ), and (0.17 wt% toluene solution, 0.1 mL) were added to each of six 30 mL vials for about 12 hours under vacuum. It was left to stand. Thereafter, the reaction was performed at 180 ° C. for 2 hours, and the vial reaction was stopped for a predetermined time, and the polymerization yield and molecular weight were measured by ¹ H NMR spectroscopy and GPC. The polymerization results are shown in Table 4 below.

Polymerization time (h) yield(%) Mw (e ^-3 g / mol) PDI (M _w / M _n ) 0.25 35 141 1.19 0.5 59 277 1.30 0.75 76 368 1.60 One 84 417 1.79 2 92 447 1.99

5. Comparative example  One : tin (II) 2- ethylhexanoate  With catalyst Polylactide  polymerization

Lactide monomer (2 g, 13.8 mmol) and tin (II) 2-ethylhexanoate (0.14 wt% toluene solution, 0.1 mL) were added to six 30 mL vials, respectively, and left for 12 hours under vacuum. Thereafter, the reaction was performed at 180 ° C. for 2 hours, and the vial reaction was stopped for a predetermined time, and the polymerization yield and molecular weight were measured by ¹ H NMR spectroscopy and GPC. The polymerization results are shown in Table 5.

Polymerization time (h) yield(%) Mw (e ^-3 g / mol) PDI (M _w / M _n ) 0.25 13 63 1.30 0.5 24 109 1.39 0.75 38 150 1.59 One 46 215 1.81 2 73 378 2.10

6. Comparative example  2 : tin (Ⅱ) butoxide  With catalyst Lactide  polymerization

Lactide monomer (2 g, 13.8 mmol), tin (II) butoxide, (hereinafter Sn (OBu) ₂ ), and (0.09 wt% toluene solution, 0.1 mL) were added to six 30 mL vials, respectively, for about 12 hours under vacuum. It was left to stand. Thereafter, the reaction was performed at 180 ° C. for 2 hours, and the vial reaction was stopped for a predetermined time, and the polymerization yield and molecular weight were measured by ¹ H NMR spectroscopy and GPC. The polymerization results are shown in Table 6.

Polymerization time (h) yield(%) Mw (e ^-3 g / mol) PDI (M _w / M _n ) 0.25 17 67 1.25 0.5 30 140 1.49 0.75 42 180 1.58 One 52 250 1.81 2 77 380 1.98

4 and 5 show the results of polylactide polymerization according to Examples and Comparative Examples, respectively, as a change in polymerization yield and molecular weight with respect to the polymerization time. As can be seen in Tables 3 to 7 and FIGS. 4 and 5, tin (II) 2-ethylhexanoate of Comparative Example 1 or tin (II) butoxide of Comparative Example 2 used in conventional polylactide polymerization. In comparison, it can be seen that the polymerization performance is higher when using the tin (II) alkoxide catalyst having an alkoxy group having 5 or more carbon atoms in the examples.

In addition, after the polymerization reaction proceeded for 2 hours, as a result of examining the molecular weight of the polymerized polylactide resin, tin having a carbon number of 5 or more according to the embodiment (compared to the case of using the organic tin catalyst according to Comparative Examples 1 and 2) II) When the alkoxide catalyst was used, the molecular weight of the polymerized polylactide resin was higher.

Therefore, in the case of using the organometallic catalyst for producing polylactide of the present invention, polylactide having a high molecular weight can be obtained in high yield, and can be usefully used in the industrial field for producing polylactide resin.

1 is a ¹ H NMR spectrum of Tin (II) alkoxide compounds according to the synthesis example of the present invention.

2 is a ¹³ C NMR spectrum of Tin (II) alkoxide compounds according to the synthesis example of the present invention.

Figure 3 is a ¹¹⁹ Sn NMR spectrum of the Tin (II) alkoxide compound according to the synthesis example of the present invention.

4 and 5 are graphs showing the results of lactide polymerization using the tin alkoxide catalyst according to the synthesis example and the tin (II) 2-ethylhesanoate catalyst of Comparative Example 1 in terms of polymerization yield and molecular weight change according to polymerization time. to be.

Claims (12)

An organometallic catalyst for preparing polylactide resin by ring-opening polymerization reaction of a lactide monomer represented by Formula 1 below: Formula 1 R ₁ O-Sn-OR ₂ In Formula 1, R ₁ and R ₂ are each independently a primary, secondary, or tertiary alkyl group having 5 to 30 carbon atoms. The method of claim 1, R ₁ and R ₂ of Formula 1 are each independently C ₆ H ₁₃ , C ₈ H ₁₇ , or C ₁₂ H ₂₅ An organometallic catalyst. The method of claim 1, An organometallic catalyst which is Sn (O (CH ₂ ) ₅ CH ₃ ) ₂ , Sn (O (CH ₂ ) ₇ CH ₃ ) ₂ , or Sn (O (CH ₂ ) ₁₁ CH ₃ ) ₂ . In the presence of an organometallic catalyst represented by the formula (1), a method for producing a polylactide resin comprising the step of ring-opening polymerization of the lactide monomer: Formula 1 R ₁ O-Sn-OR ₂ In Formula 1, R ₁ and R ₂ are each independently a primary, secondary, or tertiary alkyl group having 5 to 30 carbon atoms. The method of claim 4, wherein The organometallic catalyst is a method for producing a polylactide resin is added in a ratio of 0.001 to 0.1 mol relative to 100 mol of lactide monomer. The method of claim 4, wherein The organometallic catalyst is a polylactide resin of Sn (O (CH ₂ ) ₅ CH ₃ ) ₂ , Sn (O (CH ₂ ) ₇ CH ₃ ) ₂ , or Sn (O (CH ₂ ) ₁₁ CH ₃ ) ₂ . Manufacturing method. The method of claim 4, wherein The ring-opening polymerization is a method of producing a polylactide resin proceeds by bulk polymerization or solution phase polymerization. The method of claim 4, wherein The ring-opening polymerization is a method for producing a polylactide resin is carried out at a temperature of 120 to 220 ℃. Polylactide resin prepared by the method according to claim 4. The method of claim 9, Polylactide resin having a weight average molecular weight of 100,000 to 1,000,000. The method of claim 9, Polylactide resin having an acidity value of less than 50 meq / kg. A polylactide resin composition comprising the polylactide resin of claim 9.

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