KR100254695B1 - Copolyester resin and its preparation method - Google Patents

Abstract

PURPOSE: A copolyester resin obtained from at least one kind of bifunctional glycol, aliphatic polyester and derivatives thereof, and a process for producing copolyester resin prepared from aromatic acid ester and derivatives thereof are provided. Therefore, the obtained resin satisfies excellent physical properties and biodegradability. CONSTITUTION: This copolyester resin is obtained by using one or more diol monomers selected from ethylene glycol and 1,4-butanediol; a bifunctional aliphatic carboxylic acid-based monomer of dimethylsuccinate or a bifunctional aliphatic carboxylic acid-based monomer of succinic acid; and a polyfunctional aromatic carboxylic acid-based monomer of terephthalic acid, isophthalic acid, pyromellitic acid, trimethylpyrotrimellitate, dimethylterephthalate or dimethylisophthalate, wherein the weight ratio of ethylene glycol to 1,4-butanediol of the diol monomer is 30:70 to 0:100 and the weight ratio of aliphatic to aromatic of the carboxylic acid-based monomer is 60:40 to 99:1.

Description

Copolyester Resin and Manufacturing Method Thereof

The present invention relates to a copolyester resin and a method for preparing the same, and more particularly, to a copolyester having excellent biodegradability prepared from at least one difunctional glycol, aliphatic polyester and derivatives thereof, and aromatic ester acid and derivatives thereof. An ester resin and its manufacturing method are related.

In the following description, the term carboxylic acid monomer is meant to include carboxylic acids and ester derivatives thereof used as monomers.

Looking at the recent social and environmental trends, social problems with serious environmental pollution are also emerging around the world. Especially, since plastics used for various uses are hardly decomposable materials, they are destroying the natural environment, and regulations or implementation steps are taken. Is in.

In general, aliphatic polyesters are biodegradable (Journal of Macromol. SCI-Chem., A23 (3), 1986, 393 ~ 409), but have low melting point and poor physical properties such as heat resistance and mechanical strength. While the use is limited below, aromatic polyesters are known to have good physical properties but no biodegradability (R & D Evalulation Report No. 47, January, 1990, Chart 3).

In addition, in order to solve the problem of environmental pollution, attempts have recently been made to produce polymers that can be rapidly decomposed in an ecosystem by mixing polyethylene and starch, and various biodegradable polymers are actually used. to be.

As part of this attempt, the synthesis of biodegradable polymers using polyesters widely used in various fields has been studied [Journal of Applied Polmer Science] Nol. 26 (1981) P. 441-448]. After heating and melting the aromatic polyester, the aliphatic polyester is added together with the catalyst and reacted with stirring to form a typical transesterification reaction to form a biodegradable irregular copolymer. It is known to depend.

However, when the irregular copolymer is prepared in this way, thermal decomposition of the polyester is difficult to obtain the desired degree of polymerization and physical properties, and when the content of the aromatic polyester is increased to obtain the desired physical properties, the biodegradability is encountered.

Therefore, the present invention is to copolymerize by setting the reaction conditions of the aliphatic carboxylic acid monomer and the aromatic carboxylic acid monomer in order to improve the physical properties and biodegradability at the same time, the nose having both excellent biodegradability of the aliphatic polyester and excellent mechanical strength of the aromatic polyester It aims at manufacturing polyester.

According to the present invention to achieve the above object, at least one diol monomer selected from ethylene glycol and 1,4-butanediol; Difunctional aliphatic carboxylic acid monomers of dimethylsuccinate or succinic acid; Using a polyfunctional aromatic carboxylic acid monomer of terephthalic acid, isophthalic acid, pyromellitic acid, trimethylpyro trimellitate, dimethyl terephthalate or dimethylisophthalate, the ratio of ethylene glycol to 1,4-butanediol in the diol monomers is determined by weight ratio. To 30:70 to 0: 100, and an aliphatic to aromatic ratio of the carboxylic acid monomers in a weight ratio of 60:40 to 99: 1, a number average molecular weight of 30,000 to 50,000, a tensile strength of 300 to 500 kg / Copolyester resin of cm <2>, elongation 200-400%, melting | fusing point 90-120 degreeC is provided.

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

In the present invention, the ratio of aliphatic to aromatic in the carboxylic acid monomers is preferably 60:40 to 99: 1 by weight. Among the carboxylic acid monomers, when the aromatic carboxylic acid monomer is added in an amount of more than 40 parts by weight, the melting point is lowered and the biodegradability is also decreased, and when less than 1 part by weight, the hardness is poor. Examples of carboxylic acid monomers that can be used include dimethyl succinate or succinic acid as aliphatic carboxylic acid monomers, and dimethyl terephthalate, trimethyl trimellitate, dimethyl isophthalate, terephthalic acid, isophthalic acid or pyromellitate as aromatic carboxylic acid monomers. There is a mountain.

At least one selected from ethylene glycol and 1,4-butanediol is used as the diol monomer, and the ratio of ethylene glycol to 1,4-butanediol in the diol monomer is preferably 30:70 to 0: 100 by weight. If ethylene glycol exceeds 30%, it does not have the desired melting point.

The molar ratio of carboxylic acid monomer to diol monomer used as the monomer is preferably 1: 1.25 to 1: 2. When the molar ratio is lower than 1: 1.25, the color is poor and the reactivity is lowered. When the molar ratio is higher than 1: 2, only the manufacturing cost is increased without improving the reactivity.

The copolyester of the present invention may be prepared by condensation polymerization of the above monomers at a temperature range of 150 to 230 ° C, followed by esterification or transesterification at a temperature of 160 to 250 ° C. In this case, it is preferable to add an esterification reaction or transesterification catalyst at the beginning of the esterification reaction or transesterification reaction, and to add a condensation polymerization catalyst and a stabilizer at the end of the esterification or transesterification reaction or at the beginning of the condensation polymerization. Although it depends on the amount of catalyst and stabilizer, it is suitable between 90 and 300 minutes.

Examples of the stabilizer include neopentyl-diaryl-oxytriphosphate, triphenylphosphine, trimethyl phosphate, and the like, in particular trimethyl phosphate is advantageous and the amount of use is preferably 0.02 to 1 parts by weight. If the amount of the stabilizer is less than 0.02 parts by weight, the effect of addition is insufficient. If the amount of the stabilizer is more than 1 part by weight, the reaction time becomes long, resulting in a problem of deterioration of physical properties.

In addition, tetrabutyl titanate is suitable as a catalyst added at the beginning of an esterification reaction or transesterification reaction, and the addition amount is 0.01-1 weight part. When the amount of tetrabutyl titanate added is less than 0.01 part by weight, the reaction rate is slowed, and thus the outflow of methanol or water is slowed down. When the amount of tetrabutyl titanate is more than 1 part by weight, the outflow of methanol and water is rapid, but the color of the copolyester produced is poor.

In the case of polycondensation, dibutyl tin oxide, tetrabutyl titanate or the like can be used as a catalyst. The amount of the polycondensation catalyst added is preferably 0.1 to 1.5 parts by weight. If the addition amount of the polycondensation catalyst is less than 0.1 parts by weight, the intrinsic viscosity does not increase and the reaction rate is slow.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, this invention is not limited to an Example.

Evaluation of the biodegradability of the copolyester resin presented in the following examples is carried out according to a known method (Journal of Applied Polymer Science, Vol. 24 (1979), P.1701 ~ 1711). To explain this, first, 100 micromolar phosphate buffer solution having a pH of 7.0 was used as the reaction solution, and 20 mg of copolyester powder or 0.22-0.27 mm thick film was added to the solution. The volume of the liquid was 1 ml. Thereafter, the reaction solution was reacted with stirring at 150 rpm for 16 hours at 37 ° C., and then the reaction solution was filtered to measure the total amount of water-soluble carbon in the filtrate, and substituted in the following formula to calculate the biodegradation rate.

Biodegradation rate (%) = (total amount of carbon in aqueous solution / amount of polymer used) x 100

In addition, the melting point was measured by differential scanning calorimetry (DSC) at a temperature rise rate of 10 ° C. per minute, and tensile strength and elongation were measured by a universal testing machine (UTM).

Example 1

80.3 g of dimethyl succinate, 9.4 g of dimethyl terephthalate, 99.1 g of 1,4-butanediol, 6.2 g of ethylene glycol, and 0.03 g of tetrabutyl titanate as catalysts were mixed and heated to 200 ° C. The reaction was carried out until it flowed out.

After the completion of the transesterification reaction, 0.03 g of tetrabutyl titanate, 0.5 g of dibutyl tin oxide, and 0.25 g of trimethyl phosphate as a stabilizer were added by slurry to ethylene glycol or 1,4-butanediol, and then the mixture was added at 230 ° C. After 10 minutes of mixing well, condensation polymerization was carried out at a pressure of 0.03 mmHg while gradually raising the temperature to 245 ° C. Copolyesters were prepared by stopping the reaction after discharging by measuring the load corresponding to the desired viscosity.

Melting point, tensile strength, elongation and biodegradation rate of the obtained copolyester were measured. The measurement results are shown in Table 1 below.

EXAMPLES 2-7

The same procedure as in Example 1 was repeated except that various changes were made to the composition of the monomers as shown in Table 1.

Comparative Example 1

90.6 g of dimethyl succinate, 97 g of dimethyl terephthalate, 153 g of 1,4-butanediol, 6.2 g of ethylene glycol, and 0.03 g of tetrabutyl titanate as catalysts were heated and the temperature was raised to 200 ° C. React until

After the completion of the transesterification reaction, 0.03 g of tetrabutyl titanate, 0.5 g of dibutyl tin oxide, and 0.25 g of trimethyl phosphate as a stabilizer were added by slurry to ethylene glycol or 1,4-butanediol, and then the mixture was added at 230 ° C. After mixing well for 10 minutes, the temperature was gradually raised to 245 ° C. while condensation polymerization was carried out at a pressure of 0.03 mmHg, and measured under a load corresponding to a desired viscosity.

Melting point, tensile strength, elongation and biodegradation rate of the obtained polymer were measured. The measurement results are shown in Table 1 below.

Comparative Example 2

The same procedure as in Comparative Example 1 was repeated except that the composition of the monomers was variously changed as shown in Table 1.

Claims (5)

At least one diol monomer selected from ethylene glycol and 1,4-butanediol; Difunctional aliphatic carboxylic acid monomers of dimethylsuccinate or succinic acid; Using a polyfunctional aromatic carboxylic acid monomer of terephthalic acid, isophthalic acid, pyromellitic acid, trimethylpyro trimellitate, dimethyl terephthalate or dimethylisophthalate, the ratio of ethylene glycol to 1,4-butanediol in the diol monomers is determined by weight ratio. To 30:70 to 0: 100, and an aliphatic to aromatic ratio of the carboxylic acid monomers in a weight ratio of 60:40 to 99: 1, a number average molecular weight of 30,000 to 50,000, and a tensile strength of 300 to 500 kg. / Cm 2, elongation 200 to 400%, melting point 90 ~ 120 ℃ copolyester resin. At least one diol monomer selected from ethylene glycol and 1,4-butanediol; Difunctional aliphatic carboxylic acid monomers of dimethylsuccinate or succinic acid; The polyfunctional aromatic carboxylic acid monomer of terephthalic acid, isophthalic acid, pyromellitic acid, trimethylpyro trimellitate, dimethyl terephthalate or dimethyl isophthalate may be used in a weight ratio of ethylene glycol to 1,4-butanediol in the diol monomer. 0: 100 and the weight ratio of aliphatic to aromatic among the carboxylic acid monomers is 60:40 to 99: 1, and 0.01 to 1 parts by weight of catalyst is added for esterification or transesterification, and 0.1 to 1.5 parts by weight of shaft A method for producing a copolyester resin, comprising adding a polymerization catalyst and 0.02 to 1 part by weight of a stabilizer at the end of esterification or transesterification or at the beginning of condensation polymerization. The method for preparing copolyester resin according to claim 2, wherein tetrabutyl titanate is used as the transesterification catalyst. The method for preparing copolyester resin according to claim 2, wherein tetrabutyl titanate, tetraethyl titanate and dibutyl tin oxide are used as a catalyst during the polycondensation. The method for producing a copolyester resin according to claim 2, wherein trimethyl phosphate is used as a stabilizer.