KR101496634B1 - Method for preparing polyester resin copolymerized with neopentyl glycol - Google Patents

Abstract

A process for producing a polyester resin copolymerized with neopentyl glycol, wherein the reactivity of the polymerization raw material is excellent and the metal content in the polymerized resin is reduced, is disclosed. The production method of the polyester resin comprises an acid component containing at least 80 mol% of a terephthalic acid component and an acid component containing 10 to 80 mol% of neopentyl glycol and 20 to 90 mol% of an aliphatic or alicyclic diol copolymer having 2 to 10 carbon atoms Esterifying the glycol component comprising the component; And polycondensation of the esterification reaction product as a polycondensation catalyst in the presence of titanium dioxide and a silicon dioxide copolymer.

Neopentyl glycol, polyester, ethylene glycol, terephthalic acid, dimethyl terephthalate, titanium, catalyst

Description

TECHNICAL FIELD [0001] The present invention relates to a method for preparing a polyester resin copolymerized with neopentyl glycol,

The present invention relates to a process for producing neopentyl glycol-copolymerized polyester resin, and more particularly to a process for producing neopentyl glycol-copolymerized polyester resin having excellent reactivity of a polymerization raw material and having a reduced metal content in a polymerized resin And a method for producing the resin.

BACKGROUND ART Polyester resins are important materials in fields such as packaging materials, molded products, and films. However, since homopolymers using only terephthalic acid and ethylene glycol as raw materials are unsatisfactory in moldability, polyester resins copolymerized with various glycols or dicarboxylic acids are widely used commercially. Such a polyester resin is mainly produced by using a germanium catalyst, but the germanium catalyst is excessively volatile since the catalyst activity is relatively slow and volatilizes during the reaction.

The titanium alkoxide-based catalyst disclosed in U.S. Patent No. 5,681,918 and U.S. Patent No. 5,744,571 has a smaller input amount than the antimony catalyst and can improve the reactivity but is sensitive to moisture and precipitates as precipitates And is difficult to handle, and is affected by the moisture generated in the transesterification reaction. U.S. Patent No. 5,684,116 and U.S. Patent No. 5,789,528 disclose the use of a titanium-based compound such as a titanium dioxide and a silicon dioxide copolymer and a titanium dioxide and a zirconium dioxide copolymer as polycondensation catalysts, In the case of polyester resins, the case where the copolymerization ratio of diols exceeds 20% is not disclosed at all, and the possibility of the reaction in this case is not specifically disclosed.

In order to solve the above-mentioned problems, the present inventors have conducted extensive research, and as a result, it has been found that when a polyester resin is produced by copolymerizing neopentyl glycol and using a specific titanium compound as a polycondensation catalyst, , A polyester resin having a reduced metal content in the polymerized resin can be produced. Accordingly, an object of the present invention is to provide a process for producing a polyester resin copolymerized with neopentyl glycol, which is excellent in reactivity of a polymerization raw material and has a reduced metal content in a polymerized resin, as compared with a conventional copolymerized polyester resin .

In order to attain the above object, the present invention provides a terephthalic acid composition comprising an acid component containing at least 80 mol% of a terephthalic acid component and 10 to 80 mol% of neopentyl glycol and 20 to 90 mol% of an aliphatic or alicyclic Esterifying the glycol component comprising the diol copolymerization component; And polycondensation of the esterification reaction product as a polycondensation catalyst in the presence of titanium dioxide and a silicone dioxide copolymer. The present invention also provides a process for producing a polyester resin.

Here, the amount of the polycondensation catalyst to be used is 1 to 100 ppm based on the amount of the titanium element and 10 ppm or less based on the amount of the silicon element based on the weight of the final polyester resin, and the titanium dioxide and the silicon dioxide copolymer So that the molar ratio of titanium to silicon is preferably 20: 1 to 2: 1.

The process for producing a polyester resin according to the present invention is excellent in reactivity of the polymerization raw material, and can not only reduce the metal content in the polymerized resin but also can be economically produced.

Hereinafter, the present invention will be described in detail.

According to the present invention, in order to produce a polyester resin, first, a dicarboxylic acid component and a glycol component are subjected to an esterification reaction or an ester exchange reaction. The esterification reaction (hereinafter referred to as transesterification reaction) is usually carried out in such a manner that the total glycol component including ethylene glycol and neopentyl glycol is added to the dicarboxylic acid component such as terephthalic acid at a molar ratio of 1.05 to 3.0 And is carried out at a temperature of 230 to 260 ° C, preferably 240 to 260 ° C, more preferably 245 to 255 ° C and a pressure of 0.1 to 3.0 kg / cm 2. The esterification reaction time is usually about 100 to 300 minutes, which may vary depending on the reaction temperature, the pressure, and the molar ratio of glycol to dicarboxylic acid used. When the process for producing a polyester resin according to the present invention is divided into the first stage of the esterification reaction and the second stage of the polycondensation reaction, the esterification reaction does not require a catalyst, but if necessary, The catalyst may be added. The esterification reaction may be carried out in a batch or continuous manner, and each of the starting materials may be added separately. However, a dicarboxylic acid component such as terephthalic acid may be added to the glycol component to be added in the form of a slurry .

In order to improve the moldability or other physical properties of a homopolymer produced only from terephthalic acid and ethylene glycol, the glycol component includes neopentyl glycol, and also ethylene glycol, 1,2-propanediol, 1,3-propane Diol, 1,4-butanediol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, And aliphatic or alicyclic diol copolymerization components having 2 to 10 carbon atoms, such as a mixture of two or more monomers. In the glycol component used in the production of the polyester resin according to the present invention, the content of neopentyl glycol is 10 to 80 mol%, preferably 20 to 70 mol%, more preferably, 25 to 65 mol%. The amount of neopentyl glycol to be used is an amount corresponding to the mole% of neopentyl glycol desired in the final polymer. If the content of the neopentyl glycol is less than 10 mol%, it is difficult to prevent molding defects due to crystallization of the polyester resin. If the content exceeds 80 mol%, there is a problem that the polymerization reaction is slowed down. In the glycol component, the content of the aliphatic or alicyclic diol copolymerizable component having 2 to 10 carbon atoms other than neopentyl glycol is 20 to 90 mol%, preferably 30 to 80 mol%, more preferably 35 to 75 mol% . When the copolymerized glycol component other than the neopentyl glycol and the aliphatic or alicyclic copolymer component is contained, the content thereof is 30 mol% or less, for example, 1 to 20 mol%.

In addition, the dicarboxylic acid component may contain, in addition to terephthalic acid and its terephthalic acid component such as lower alkyl (having 1 to 4 carbon atoms) ester, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, And may further contain copolymerization components for improving physical properties such as a carboxylic acid, a carboxylic acid, a succinic acid, a glutaric acid, an adipic acid, a sebacic acid, a 2,6-naphthalene dicarboxylic acid and a lower alkyl ester thereof. Here, the content of the terephthalic acid component is at least 80 mol%, preferably at least 90 mol% or more, relative to the total acid component. When other copolymerizable acid components other than the terephthalic acid component are included, the content thereof is 20 mol% or less, preferably 10 mol% or less, for example, 1 to 5 mol%, based on the total acid component. If necessary, a small amount of polyfunctional group compounds such as trimellitic acid hydride, trimellitic acid, trimethylol propane, pentaerythritol and the like may be used as the copolymerizable acid component or the copolymerized glycol component.

After completion of the first stage esterification reaction, a second stage polycondensation reaction is carried out. The polycondensation step is polycondensation of the esterification reaction product and is usually carried out at a reaction temperature of 250 to 290 ° C, preferably 260 to 280 ° C and a reduced pressure of 400 to 0.1 mmHg. Under such depressurization conditions, glycol, a by-product of the polycondensation reaction, is removed. The polycondensation step may be carried out for a necessary period of time until the desired intrinsic viscosity is reached. For the polycondensation reaction, a polycondensation catalyst and, if necessary, a stabilizer, a coloring agent and the like are added to the product of the esterification reaction.

Generally, polycondensation catalysts have been appropriately selected among titanium, germanium and antimony compounds. Among them, the titanium-based catalyst is advantageous in that it can be reacted even when used in a small amount compared to the antimony-based catalyst, and is less expensive than the germanium-based catalyst. In general, as the titanium-based catalyst, tetraethyl titanate, acetyl tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, polybutyl titanate, 2-ethylhexyl titanate, octylene glycol titanate, lactate There is known a titanate, triethanolamine titanate, acetylacetonate titanate, ethylacetoacetic ester titanate, isostearyl titanate, titanium dioxide, titanium dioxide and silicon dioxide copolymer, and titanium dioxide and zirconium dioxide copolymer In the present invention, titanium dioxide and silicon dioxide copolymers which are not sensitive to moisture and are easy to store and handle and which can improve the hue and transparency of a polyester resin are used as a titanium polycondensation catalyst.

In the titanium dioxide and the silicon dioxide copolymer, the molar ratio of titanium to silicon is preferably 20: 1 to 2: 1, more preferably 16: 1 to 8: 1. Here, when the content of the silicon component is excessively small or large, the polymerization reactivity of the reaction raw material may be deteriorated. The titanium dioxide and the silicon dioxide copolymer are preferably dissolved in the glycol component at a concentration of 4 wt% or less, for example, 0.5 to 3 wt%. If the preparation concentration is more than 4% by weight, the catalyst may not be completely dissolved during the reaction and the polymerization reaction rate may be lowered, so that a copolymerized polyester resin having a desired degree of polymerization can not be obtained. The amount of the catalyst to be used is 1 to 100 ppm, preferably 1 to 50 ppm, based on the amount of the titanium element, and 10 ppm or less based on the amount of the silicon element, based on the weight of the final polymer (polyester resin) 0.1 to 10 ppm. The addition amount of the catalyst affects the hue of the final polymer, and therefore can be controlled depending on a desired color, a stabilizer to be used, a coloring agent and the like. If the amount of the titanium element is less than 1 ppm, the desired degree of polymerization can not be attained. If the amount of the titanium element is more than 100 ppm, the color of the final polymer becomes yellow. In addition, when the amount of silicon element is less than 0.1 ppm or exceeds 10 ppm, the reactivity of the reaction raw material may be lowered.

In the production of the polyester resin according to the present invention, stabilizers, coloring agents and the like may preferably be used as additives in the polycondensation reaction. Phosphoric acid, trimethyl phosphate, triethyl phosphate, a mixture thereof, and the like can be used as the stabilizer, and the amount of the stabilizer is 10 to 100 ppm based on the weight of the phosphorus. If the addition amount of the stabilizer is less than 10 ppm, there is a problem that the effect of stabilization is insufficient and discoloration becomes yellow, and when it exceeds 100 ppm, the desired high degree of polymerization can not be achieved. As a coloring agent to be added to improve color, a conventional coloring agent such as cobalt acetate or cobalt propionate may be used, and the amount thereof is preferably 0 to 100 ppm based on the weight of the final polymer. As the coloring agent, a coloring agent may be used as a conventional organic compound. The polyester resin produced according to the present invention generally has an intrinsic viscosity of 0.45 to 1.35 dl / g as measured by the measuring method described in the examples.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The following Examples illustrate the present invention, and the scope of the present invention is not limited by the following Examples. In the following examples, the intrinsic viscosity (IV) of the polyester resin was measured using a Ubbelohde viscometer in a 35 ° C thermostatic chamber after dissolving the resin in 150 ° C ortho-chlorophenol at a concentration of 0.12 wt%.

[Example 1] Production of polyester resin

3.2 kg of terephthalic acid, 7.6 kg of neopentyl glycol and 13.5 kg of ethylene glycol were charged into a 5 L reactor equipped with a stirrer and an outlet condenser, the pressure was raised to 2.0 kg / cm 2 with nitrogen, the temperature of the reactor was gradually raised to 255 DEG C Lt; / RTI > The water generated at this time was discharged out of the system to carry out the esterification reaction. When the generation and the discharge of water were finished, the reaction product was transferred to a polycondensation reactor equipped with a stirrer, a cooling condenser and a vacuum system. Further, titanium dioxide and silicon dioxide copolymer (Ti: Si = 15: 1, molar ratio) were prepared by dissolving ethylene glycol in a concentration of 2 wt%. The prepared catalyst was added to the esterification reaction product so that the amount of titanium was 17 ppm based on the amount of the final polymer and 1.1 ppm based on the amount of silicon based on the amount of the silicon based on the amount of the titanium element. Based on the amount of the final polymer, and cobalt acetate was added thereto so that the final amount of cobalt acetate was 30 ppm based on the amount of the final polymer. The internal temperature of the reactor was increased from 240 DEG C to 275 DEG C and the pressure was lowered to 50 mmHg from the atmospheric pressure at a first pressure for a period of 30 minutes under a low vacuum to remove ethylene glycol and then gradually depressurized to 0.1 mmHg, The reaction was continued until the intrinsic viscosity was reached, and the produced polyester resin was discharged and cut into chips. The intrinsic viscosity of the prepared neopentyl glycol copolymer polyester resin was measured and shown in Table 1 along with the reaction time.

[Comparative Example 1] Production of polyester resin

A polyester resin was prepared in the same manner as in Example 1, except that the kind and amount of the catalyst were changed as shown in Table 1 below. The intrinsic viscosity of the produced polyester resin was measured, and the results are shown in Table 1 together with the reaction time. In Table 1 below, Catalyst-1 represents a titanium dioxide and silicon dioxide copolymer catalyst, and Catalyst-2 represents a germanium dioxide catalyst.

Catalyst type Catalyst amount (ppm) Intrinsic viscosity (dL / g) The polycondensation time (min) Example 1 Catalyst-1 17 0.79 155 Comparative Example 1 Catalyst-2 200 0.79 245

[Example 2] Production of polyester resin

3.2 kg of terephthalic acid, 7.6 kg of neopentyl glycol and 13.5 kg of ethylene glycol were charged into a 5 L reactor equipped with a stirrer and an outlet condenser, the pressure was raised to 2.0 kg / cm 2 with nitrogen, the temperature of the reactor was gradually raised to 255 DEG C Lt; / RTI > The water generated at this time was discharged out of the system to carry out the esterification reaction. When the generation and the discharge of water were finished, the reaction product was transferred to a polycondensation reactor equipped with a stirrer, a cooling condenser and a vacuum system. Further, titanium dioxide and silicon dioxide copolymer (Ti: Si = 15: 1, molar ratio) were prepared by dissolving ethylene glycol in a concentration of 2 wt%. The prepared catalyst was added to the above esterification reaction product so that the amount of titanium was 30 ppm based on the amount of the final polymer and 1.9 ppm based on the amount of silicon based on the amount of the final polymer and triethyl phosphate was added based on the amount of phosphorous To 40 ppm based on the final amount of the polymer, and cobalt acetate was added to the final polymer in an amount of 40 ppm based on the amount of the cobalt source. While the internal temperature of the reactor was increased from 240 DEG C to 275 DEG C, the pressure was first reduced to 50 mmHg at normal pressure and subjected to a low-vacuum reaction for 30 minutes to remove ethylene glycol, and then the pressure was gradually reduced to 0.1 mmHg, The reaction was continued until the viscosity reached, and the produced polyester resin was discharged and cut into chips. The intrinsic viscosity of the produced neopentyl glycol copolymer polyester resin was measured and shown in Table 2 together with the reaction time.

[Comparative Example 2] Production of polyester resin

A polyester resin was prepared in the same manner as in Example 2 except that the kind and amount of the catalyst were changed as shown in Table 2 below. The intrinsic viscosity of the polyester resin thus prepared was measured and shown in Table 2 together with the reaction time. In Table 2 below, Catalyst-1 represents a titanium dioxide and silicon dioxide copolymer catalyst, and Catalyst-2 represents a germanium dioxide catalyst.

Catalyst type Catalyst amount (ppm) Intrinsic viscosity (dL / g) The polycondensation time (min) Example 2 Catalyst-1 30 0.88 155 Comparative Example 2 Catalyst-2 250 0.83 270

From the above Examples and Comparative Examples, it has been found that, in the case of using a titanium dioxide and a silicon dioxide copolymer as polycondensation catalysts and a phosphorus compound as a stabilizer in the production of neopentyl glycol-copolymerized polyester resin, It can be seen that the intrinsic viscosity and the productivity of the resin are excellent as compared with the polyester resin produced. Further, in the case of the examples, the amount of the catalyst can be reduced, and a polyester resin can be economically produced by using no expensive germanium dioxide catalyst.

Claims (6)

An ester component comprising an acid component comprising at least 80 mole percent terephthalic acid component and a glycol component comprising 10 to 80 mole percent neopentyl glycol and 20 to 90 mole percent ethylene glycol; And Polycondensation of said esterification reaction product as polycondensation catalyst in the presence of titanium dioxide and silicon dioxide copolymer, The amount of the polycondensation catalyst to be used is 1 to 100 ppm based on the amount of the titanium element based on the weight of the final polyester resin and 10 ppm or less based on the amount of the silicon element. In the titanium dioxide and the silicon dioxide copolymer, Wherein the molar ratio of titanium to silicon is from 20: 1 to 2: 1. delete delete delete The method of claim 1, wherein the polycondensation step is carried out in the presence of a phosphorus compound as a stabilizer, wherein the phosphorus compound is added in an amount of 10 to 100 ppm based on the weight of the final polyester, And a method for producing the copolymerized polyester resin. The method for producing a polyester resin according to claim 1, wherein the polyester resin has an intrinsic viscosity of 0.45 to 1.35 dl / g.