KR20140021755A - Method for preparing esterification reaction product and method for preparing polyester using the esterification reaction product - Google Patents

Abstract

The present invention relates to a method for preparing esterification reaction products and a method for preparing polyester using esterification reaction products and more specifically, to a method for preparing esterification reaction products in which the content of dipropylene glycol is reduced, and to a method for preparing polyester using the esterification reaction products, in which generation of impurities such as acrolein, aryl alcohol, and the likes is reduced. [Reference numerals] (AA) End; (BB) Example 1; (CC) Example 2

Description

Method for producing esterification product and method for preparing polyester using the esterification product {METHOD FOR PREPARING ESTERIFICATION REACTION PRODUCT AND METHOD FOR PREPARING POLYESTER USING THE ESTERIFICATION REACTION PRODUCT}

The present invention relates to a method for preparing an esterification reaction product and a method for preparing a polyester using the esterification reaction product, specifically a method for producing an esterification reaction product having a reduced content of dipropylene glycol and the esterification reaction. The present invention relates to a method for producing a polyester with reduced amount of impurities such as acrolein and allyl alcohol using the product.

Polyester is widely used in fibers, films, and other moldings because of its excellent mechanical, physical, and chemical performance. In particular, polytrimethylene terephthalate has attracted attention due to its soft texture, excellent elastic recovery, dye transfer, and the like.

Polytrimethylene terephthalate (PTT) is a transesterification reaction using dimethyl terephthalate (DMT) and 1,3-propanediol (1,3-propanediol, 1,3-PDO) as raw materials, Alternatively, it may be prepared by a direct ester reaction using terephthalic acid (TPA) and 1,3-PDO as a raw material, followed by liquid phase polymerization and / or solid phase polymerization.

Specifically, the transesterification and direct esterification are carried out under a pressure of about 0.5-5 atm and conditions of about 150-250 ° C. As a result of this reaction, a product containing Bis (3-hydroxypropyl) terephthalate (BHPT) monomer and oligomer is produced, and water is also generated as a by-product and subsequently removed. Thereafter, the BHPT monomer and the oligomer are liquid-polymerized in the presence of a polymerization catalyst in a high temperature and vacuum atmosphere to obtain polytrimethylene terephthalate. At this time, propanediol (PDO) is produced as a by-product, which is recovered and reused in the ester reaction.

However, during the ester reaction, PDO undergoes a dimerization reaction between molecules, resulting in dipropylene glycol (DPG). The resulting DPG is included in the PTT polymer chain, thereby affecting the melting point, glass transition temperature, crystallinity, specific gravity, dyeability, processability of PTT. In addition, the liquid phase polymerization reaction is generally carried out at a high temperature before and after 260 ℃, at this high temperature, the polymer, DPG, or free PDO (unreacted PDO) is decomposed to produce toxic substances such as acrolein or allyl alcohol. Emissions outside of this reactor adversely affect the environment. Therefore, it is desirable to reduce the generation of DPG in the production of PTT and to suppress the production of by-products such as acrolein.

US 5,340,909 discloses the preparation of PTT with dimethyl terephthalic acid (DMT). Since the production process of the PTT is performed under mild and less acidic process conditions and the amount of DPG produced is very low, the produced polymer is stable to oxidation, and the amount of acrolein generated during production is also low. However, PTT prepared by DMT has a problem that the dyeability is poor.

On the other hand, when PTT is produced using terephthalic acid, the production amount of DPG is higher than that of DMT as a raw material (about 2 to 4 mole%), and thus there is a difficulty in increasing the production amount of acrolein in a subsequent process.

US Pat. No. 6,281,325 discloses a process for controlling DPG production to 1.6 mol% or less using Sn catalysts during esterification in the preparation of PTT. However, the additional use of the catalyst is not economical.

Therefore, when PTT is manufactured using PTA as a raw material, development of a process for minimizing the amount of DPG generated economically and efficiently is required.

The present invention is to provide a method for preparing an esterification reaction product by controlling the content of dipropylene glycol produced when preparing an esterification reaction product from dicarboxylic acid and 1,3-propanediol.

In addition, the present invention is to provide a method for producing a polyester with a minimum amount of impurities, such as acrolein or allyl alcohol.

The present invention provides a method for preparing an esterification reaction product by esterifying dicarboxylic acid and 1,3-propanediol in the presence of a metal selected from the group consisting of alkali metals and alkaline earth metals.

In addition, the present invention is prepared by the method described above, dipropylene glycol based on the total number of moles of diol contained in the esterification product An esterification reaction product containing up to 2 mol% is provided.

In addition, the present invention comprises the step of esterifying the dicarboxylic acid and 1,3-propanediol in the presence of a metal selected from the group consisting of alkali metals and alkaline earth metals to obtain an esterification reaction product; And it provides a method for producing a polyester comprising the step of liquid-polymerizing the esterification reaction product to form a polyester.

The method for preparing the polyester may further include solidifying the polyester formed by the liquid phase polymerization after the liquid phase polymerization step of the esterification reaction product.

In addition, the present invention provides a polyester prepared by the above-described method, containing 2 mol% or less of dipropylene glycol based on the total moles of diols contained in the polyester.

The present invention can produce an esterification reaction product having a reduced content of dipropylene glycol by using an alkali metal and / or an alkaline earth metal in the esterification reaction of dicarboxylic acid and 1,3-propanediol.

In addition, the present invention can be used to produce a polyester in which the amount of acrolein or allyl alcohol is minimized by using an esterification reaction product having a reduced content of dipropylene glycol.

1 is a graph showing the intrinsic viscosity change of the polyester before and after the solid-state polymerization of Examples 1 and 2 and Comparative Example 1.

Hereinafter, the present invention will be described in detail.

The present invention is characterized by the use of alkali metals and / or alkaline earth metals in the esterification reaction of dicarboxylic acids and 1,3-propanediol. As a result, an esterification reaction product having a low content of dipropylene glycol (DPG) can be obtained, and further, polyester can be prepared while minimizing generation of acrolein or allyl alcohol.

In the case of preparing PTT using dimethyl terephthalic acid (DMT) as a raw material, since DPG is produced at a low level of 1 mol% or less, and the amount of impurities generated during the liquid phase polymerization reaction is small, the need for suppressing DPG production is low. On the other hand, when PTT is prepared using terephthalic acid (PTA) as a raw material, DPG is produced at 2 mol% or more, which causes a large amount of acrolein or allyl alcohol to be emitted during liquid phase polymerization. Therefore, the present invention seeks to control the production of DPG in the esterification step.

Therefore, the present inventors, when using alkali metal and / or alkaline earth metal in the esterification reaction of dicarboxylic acid and 1,3-propanediol, the production of DPG is suppressed, using the esterification reaction product obtained through this reaction It has been found that the production of polyester can also inhibit the production of acrolein or allyl alcohol.

Specifically, in the esterification reaction of dicarboxylic acid and 1,3-propanediol, the hydroxyl group (OH group) of 1,3-propanediol is activated by a catalyst and dicarboxylic acid (for example, terephthalic acid) as a raw material. And dehydration (ie, dimerization of 1,3-propanediol) between 1,3-propanediol molecules occurs, resulting in DPG, wherein the alkali and alkaline earth metals of the present invention It interferes with the dimerization of propanediol. Accordingly, the esterification product produced by the present invention may contain dipropylene glycol in an amount of about 2 mol% or less based on the total moles of diols in the esterification product.

In addition, when the liquid phase polymerization reaction is carried out using the above-mentioned esterification product in the preparation of polyester, especially when the liquid phase polymerization reaction is performed at a high temperature, the content of dipropylene glycol in the esterification reaction product is low. The content of acrolein and / or allyl alcohol produced due to decomposition of propylene glycol can be minimized.

<Method for producing esterification reaction product>

The present invention is a method for preparing an esterification reaction product by esterifying dicarboxylic acid and 1,3-propanediol, wherein the dicarboxylic acid and 1,3-propanediol are present in the presence of an alkali metal and / or an alkaline earth metal. Esterification reaction.

The esterification reaction of the dicarboxylic acid and 1,3-propanediol is carried out in the presence of a metal selected from the group consisting of alkali metals and alkaline earth metals. The metal is used as a DPG production controlling agent capable of inhibiting the production of dipropylene glycol as described above.

Nonlimiting examples of the metal include magnesium (Mg), calcium (Ca), potassium (K), and sodium (Na). These metals may be used singly or in combination.

Examples of the compound providing the metal (hereinafter, 'metal precursor') include oxides, hydroxides, carbonates, phosphorus derivatives, alkyl derivatives, or aryl derivatives. Specifically, examples of the metal precursors include oxides, hydroxides, carbonates, phosphorus derivatives, alkyl derivatives, or aryls of metals selected from the group consisting of magnesium (Mg), calcium (Ca), potassium (K), and sodium (Na). Derivatives and the like, and preferably oxides or hydroxides of metals selected from the group consisting of magnesium (Mg), calcium (Ca), potassium (K), and sodium (Na). These may be used alone or in combination of two or more.

The content of the metal is not particularly limited. However, the content of the metal is about 1 to 1000 ppm, preferably about 20 to 100 ppm based on the total weight of the polyester after the liquid phase polymerization (ie, the polyester obtained by the liquid phase polymerization of the esterification reaction product prepared). When controlled, the effect of inhibiting DPG formation during the esterification reaction is enhanced, so that the content of DPG in the esterification reaction product can be easily controlled to about 2 mol% or less. Furthermore, the high viscosity through liquid phase polymerization or solid phase polymerization of the esterification reaction product The polyester of can be obtained. In addition, the amount of the metal to be added may be increased or decreased to increase or decrease the content of DPG included in the esterification reaction product. For example, increasing the amount of metal increases DPG production inhibition, while decreasing the amount of metal decreases the DPG production inhibitory effect.

The metal may be added at the beginning or during the esterification reaction of the dicarboxylic acid with 1,3-propanediol, and may also be added intermittently or in succession.

The 1,3-propanediol of the present invention can be obtained by any of various chemical methods or by biological conversion methods. For example, US Patent Nos. 5,015,789, 5,276,201, 5,284,979, 5,334,778 and the like.

The method for producing 1,3-propanediol by biological conversion is by a fermentation process using a feedstock prepared from a renewable source, such as a grain feedstock, US Pat. Nos. 5,633,362, 5,686,276 and 7,695,943 And many other patents.

In the present invention, in addition to 1,3-propanediol, other types of diols can be esterified together with 1,3-propanediol. The other kind of diol content may be about 50% by weight or less, preferably about 20% by weight or less, more preferably about 10% by weight or less, even more preferably about 1% by weight or less based on the total weight of the total diol. Can be.

Examples of diols other than the 1,3-propanediol include ethylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propane diol and C ₆ -C ₁₂ diols such as 2 , 2-diethyl-1,3-propane diol, 2-ethyl-2- (hydroxymethyl) -1,3-propane diol, 1,6-hexanediol, 1,8-octanediol, 1,10- Decanediol, 1,12-dodecanediol, 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol, and the like.

Dicarboxylic acid (dicarboxylic acid) used in the present invention is an organic compound containing two carboxyl groups. For example, C ₄ to C ₁₂ linear or branched alkyldicarboxylic acid, C ₃ to C ₁₂ cycloalkyldicarboxylic acid, C ₆ to C ₁₄ aryldicarboxylic acid and the like, which are alone or Two or more kinds may be mixed and used.

Specific examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, 2,2,5,5-tetramethylhexanoic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid ( sebacic acid), 1,11-undecanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, hexadecanoic acid, fumaric acid, maleic anhydride, maleic acid, terephthalic acid, iso Phthalic acid, phthalic acid, 1,3- or 1,4-cyclohexanedicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 2,6-naphthalene dicarboxylic acid Acids, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 4,4'-methylene bis (benzoic acid), hexahydrophthalic acid, and the like, which may be used alone or in combination of two or more thereof. Can be used.

Preferably the dicarboxylic acid is an aromatic dicarboxylic acid, non-limiting examples of which are terephthalic acid, isophthalic acid, phthalic acid, 1,3- or 1,4-cyclohexanedicarboxylic acid (cyclohexanedicarboxylic acid), 4,4'-biphenyl dicarboxylic acid, and 2,6-naphthalenedicarboxylic acid. Terephthalic acid is more preferred. In addition, other dicarboxylic acids such as isophthalic acid, pentanedioic acid, hexanedioic acid and the like may be used together with terephthalic acid, and the content of other dicarboxylic acids is not particularly limited, but the total weight of dicarboxylic acid may be On the basis of about 20 mol% or less, preferably about 10 mol% or less, more preferably about 1 mol% or less.

Such dicarboxylic acid is reacted with 1,3-propanediol, wherein the mixing ratio of dicarboxylic acid and 1,3-propanediol is not particularly limited. However, when the molar ratio of 1,3-propanediol to dicarboxylic acid when mixing dicarboxylic acid and 1,3-propanediol is about 1.0 to 2, preferably about 1.2 to 1.5, The production of DPG can be more effectively suppressed.

The esterification reaction of the dicarboxylic acid with 1,3-propanediol can be carried out under esterification catalysts known in the art. Non-limiting examples of the esterification catalyst include organic and inorganic compounds (eg, oxides, carbonates, phosphorus derivatives, alkyl derivatives, aryl derivatives) of metals such as titanium, tin, antimony, zirconium, and the like. Two or more kinds can be mixed and used. Specific examples include tetraisopropyl titanate, tetraisobutyl titanate, titanium butoxide, tetraethyl titanate, tetrapropyl titanate, n-butyltartrate, octyltinate, dimethyltin oxide, dibutyltin oxide, dioxane Tiltin oxide, diphenyltin oxide, tri-n-butyltin acetate, tri-n-butyltin chloride, tri-n-butyltin fluoride, triethyltin chloride, triethyltin bromide, triethyltin acetate, Trimethyltin hydroxide, triphenyltin chloride, triphenyltin bromide, triphenyltin acetate or a combination of two or more thereof, preferably tetraisopropyl titanate, tetraisobutyl titanate, titanium butoxide.

The content of the esterification catalyst is not particularly limited, and the metal component of the catalyst is 0 to 500 ppm based on the total weight of the polyester after the liquid phase polymerization (ie, the polyester obtained by the liquid phase polymerization of the esterification product to be produced). Preferably, about 50 to 300 ppm, it is possible to economically improve the reaction rate to shorten the reaction time, it is possible to prevent the production of DPG to increase the yield and purity of the final esterification reaction product. The esterification reaction catalyst may be added at the beginning of the esterification reaction of dicarboxylic acid and 1,3-propanediol or during the reaction, or may be added intermittently or continuously.

Moreover, the temperature, pressure, and time of the said esterification reaction are not specifically limited, It adjusts according to the kind of metal or dicarboxylic acid used, the degree of polymerization of a desired esterification reaction product, etc. For example, the temperature of the esterification reaction may be about 150 to 260 ℃, preferably about 180 to 250 ℃, the pressure may be about 0.1 to 10 atm, preferably about 1 to 5 atm, the reaction time is About 1 to 5 hours.

This esterification reaction can be carried out in batch form, semi-continuous form, or continuous form.

On the other hand, as the esterification proceeds, water is incidentally generated. This water is mixed in the reactor with a small amount of unreacted acid or glycol. Therefore, the present invention may further include the step of making the glycol mixed with water into the gas phase, separating the glycol from the water through a condenser or column separator at the top of the reactor and refluxing it back into the esterification reactor.

When preparing the esterification product via the esterification step as described above, the esterification product is less than or equal to about 2 mol%, preferably about 1, based on the total moles of diols contained in the product. To 2 mol% DPG.

The esterification reaction product of the present invention comprises an oligomer comprising bis (3-hydroxypropyl) terephthalic acid (BHPT) and repeating units derived from dicarboxylic acid and 1,3-propanediol. The intrinsic viscosity of the esterification product is about 0.05 to 0.4 dL / g, preferably about 0.1 to 0.3 dL / g, and the degree of polymerization (DPn) is about 1 to 20, preferably about 3 to 15. Intrinsic viscosity (IV) (dL / g) in the present invention is dissolved in a concentration of 0.25g / 50ml in 60% by weight of phenol and 40% by weight of 1,1,2,2-tetrachloroethane solvent It is then measured at 30 ° C. using a viscometer according to ASTM D4603.

This esterification reaction product can be used to prepare polymers comprising repeating units derived from acids and glycols, such as the following polyesters.

<Production method of polyester>

On the other hand, the present invention provides a method for producing a polyester comprising the step of liquid-polymerizing the above-mentioned esterification reaction product to form a polyester.

According to one embodiment of the present invention, a method of preparing a polyester is a step of esterifying a dicarboxylic acid and 1,3-propanediol in the presence of a metal selected from the group consisting of alkali metals and alkaline earth metals to obtain an esterification reaction product. ; And liquid phase polymerizing the esterification reaction product to form a polyester.

According to another example of the present invention, the method for producing a polyester may further include a step of solidifying the polyester formed by the liquid phase polymerization and then solidifying the phase after the liquid phase polymerization of the esterification reaction product. Can be.

(One) Esterification  Liquid Phase Polymerization Step of Reaction Product

In the present invention, the esterification product obtained as described above is subjected to liquid phase polymerization to form polyester.

The esterification reaction product used in the present invention has a low content of DPG as described above. Therefore, even when the liquid phase polymerization reaction is carried out at a high temperature, since the content of DPG in the esterification reaction product is as low as about 2 mol% or less, it is possible to lower the amount of acrolein or allyl alcohol generated due to the decomposition of DPG. As such, when preparing the polyester according to the present invention, it is possible to minimize the amount of impurities such as acrolein or allyl alcohol generated during the liquid phase polymerization process, compared to the conventional polyester production method. In addition, the polyester obtained after the liquid polymerization is a dipropylene glycol of about 2 mol% or less, preferably about 1 to 2 mol% based on the total number of moles of diol units contained in the polymer. It contains. The diol unit includes a PDO and a DPG.

The liquid phase polymerization may be performed in the same manner as the polymerization known in the art, for example, the polycondensation reaction of the esterification reaction product may be performed in the presence of a polycondensation reaction catalyst in a vacuum atmosphere.

On the other hand, after performing the preliminary liquid phase polymerization reaction with the esterification reaction product before the liquid phase polymerization reaction, the liquid phase polymerization reaction through the condensation polymerization may be carried out under vacuum. In the preliminary liquid phase polymerization, the temperature may be about 230 to 260 ° C., the pressure may be about 10 to 200 Torr, preferably 10 to 50 Torr, and the reaction time may be about 10 minutes to 1 hour. PDO and water are then removed.

The polycondensation reaction catalyst used in the liquid phase polymerization reaction is not particularly limited as long as it is a polycondensation reaction catalyst known in the art, and the same catalyst as the catalyst used in the esterification reaction may be used. For example, titanium, tin, antimony, zirconium, and the like, and preferably titanium butoxide, but are not limited thereto.

The content of the metal in the polycondensation reaction catalyst is not particularly limited. If the content is about 50 to 500 ppm based on the total weight of the polyester after the liquid polymerization, the polycondensation reactivity of the polyester may be further improved.

The temperature of the liquid phase polymerization reaction is not particularly limited and may be adjusted in consideration of the type of esterification reaction product used, the type of reaction catalyst, the degree of polymerization or viscosity of the polyester, the reaction pressure, the reaction time, and the like. For example, the liquid phase polymerization may be performed at about 230 to 270 ° C.

In addition, the pressure of the liquid phase polymerization reaction is not particularly limited, but may be adjusted in consideration of the type of esterification reaction product used, the type of reaction catalyst, the degree of polymerization or viscosity of the desired polyester, the reaction temperature, the reaction time, and the like. For example, the liquid phase polymerization may be performed at about 0 to 10 Torr.

In addition, the liquid phase polymerization reaction time is not particularly limited, and may be adjusted in consideration of the type of esterification reaction product used, the type of reaction catalyst, the degree of polymerization or viscosity of the desired polyester, the reaction temperature, the reaction pressure, and the like. For example, the liquid phase polymerization may be performed for about 10 minutes to 3 hours.

When the liquid phase polymerization reaction proceeds at the temperature, pressure, and time as described above, the intrinsic viscosity of the polyester after the liquid phase polymerization is reduced to about 0.3 to 0.65 dL / g, and preferably 0.4 to 0.6 dL / g, while the formation of by-products is reduced. I can regulate it.

The liquid phase polymerization may be carried out in a batch or continuous manner.

On the other hand, in addition to the esterification reaction product and the polycondensation reaction catalyst, at least one additive such as a gloss remover, a colorant, a branching agent, a stabilizer, a viscosity increasing agent, a pigment, and an antioxidant may be used for the liquid phase polymerization reaction. The one or more additives may be added during the initial liquid phase polymerization or during the liquid phase polymerization, or may be added during the following preliminary liquid phase polymerization or during the preliminary liquid phase polymerization.

The content of the additive is not particularly limited, and may be, for example, about 1 to 200 ppm based on the total weight of the polyester after liquid polymerization.

(2) solid phase polymerization step of polyester

After the liquid phase polymerization of the aforementioned esterification product, the polyester formed by the liquid phase polymerization may be solidified and then subjected to a solid phase polymerization to obtain a high molecular weight polyester. In this case, since the content of DPG in the polyester formed by the liquid phase polymerization is low to about 2 mol% or less, dipropylene glycol is about 2 based on the total mole number of the diol units included in the polyester after the solid phase polymerization. Or less, preferably in an amount of about 1 to 2 mole%.

The combination of liquid phase polymerization and solid phase polymerization in the production of the polyester of the present invention is advantageous in terms of economics and quality than the production of liquid phase polymerization alone. Polyesters, in particular PTT, are structurally similar to PET, but the structure of the PTT is more unstable and is likely to be decomposed by heat during liquid phase polymerization. In order to suppress decomposition of PTT during the liquid-phase polymerization, PTT needs to be reacted at a lower temperature than PET, for example, about 30 ° C. In this case, the polymerization reaction takes a long time, Efforts such as making a larger scale are needed. Since this effort increases the processing cost of PTT compared to PET, it may be uneconomical to produce PTT by liquid phase polymerization alone. In addition, when the residence time is increased to achieve the intrinsic viscosity (IV) of the desired polyester at low temperature, there is a concern that the quality of the polymer may be degraded. Therefore, in the present invention, the liquid phase polymerization is carried out until the IV of the polyester after the liquid phase polymerization is about 0.3 to 0.65 dL / g, preferably about 0.4 to 0.6 dL / g, and then to a desired IV at a lower temperature ( For example, the solid phase polymerization can be carried out until the IV of the polyester after the solid phase polymerization is about 0.7 to 2 dL / g), thereby obtaining polyester of high quality while being economical in the overall process.

The polyester obtained after the liquid phase polymerization is in a molten state. The method of coagulating such polyester is not particularly limited. For example, a molten polyester can be poured into distilled water at about 20 ° C. to coagulate. The polyester in the solid state can also be pelletized using a strand pelletizer, an underwater pelletizer, or a drop forming apparatus. At this time, the size of the pellet is not particularly limited, but in the case of about 1 to 50 mg / ea, preferably about 5 to 30 mg / ea, it is possible to improve the rate of solid-state polymerization, and also to increase the degree of polymerization of the final polyester. Can be increased.

Thereafter, the polyester in the solid state may be subjected to solid phase polymerization to obtain a high molecular weight polyester having an increased degree of polymerization. In this case, the intrinsic viscosity of the polyester obtained after the solid state polymerization may be about 0.7 to 2 dL / g, preferably about 0.8 to 1.5 dL / g.

The solid phase polymerization may be performed in the same manner as known in the art. The pellet is crystallized at about 150 to 180 ° C., followed by moisture drying and annealing. The dried and annealed pellets are preheated in a preheater to a reaction temperature (about 190-230 ° C.) for solid phase polymerization. In the solid state polymerization reaction, a polymerization reaction is performed by applying heat or the like to a solid polyester (eg, polyester pellet) under vacuum or nitrogen atmosphere, and by-products of 1,3-propanediol can be removed from the system and reused. .

The temperature of the solid phase polymerization reaction is not particularly limited, and may be adjusted in consideration of the degree of polymerization, viscosity, reaction pressure, reaction time, etc. of the desired polyester. For example, the temperature of the solid phase polymerization can be adjusted to about 190 to 230 ℃.

In addition, the pressure of the solid phase polymerization reaction is not particularly limited, but may be adjusted in consideration of the degree of polymerization, viscosity, reaction temperature, reaction time and the like of the desired polyester. For example, the solid phase polymerization may be carried out under atmospheric pressure or under reduced pressure.

In addition, the solid phase polymerization reaction time is not particularly limited, and may be adjusted in consideration of the degree of polymerization, viscosity, reaction temperature, reaction pressure and the like of the desired polyester. For example, the solid phase polymerization may be performed for about 5 to 30 hours.

The solid phase polymerization may be carried out batchwise or continuously.

Examples of molded articles that can be made using the polyesters of the present invention include, but are not limited to, containers (eg, bottles), compression or injection molded parts, tiles, films, and processed parts. They can be produced by injection molding, extrusion molding, compression molding and blow molding.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the following examples serve to illustrate the present invention, and the scope of the present invention is not limited thereto.

<Measurement method>

(1) acid value

0.25 g of the fully dried sample was dissolved with benzyl alcohol, chloroform was added at room temperature, and then phenol red indicator was added and titrated with 0.01 N KOH solution. The same procedure was carried out in a blank state without a sample.

The acid value was calculated using the following formula (1).

(In the above formula (1)

A is the amount of KOH ([mu] l) of 0.01 N added to the sample,

B is the amount of KOH ([mu] l) of 0.01 N added to the blank,

W is the amount (g) of the sample,

f is the factor of a 0.01 N KOH solution).

(2) Intrinsic viscosity (IV)

The intrinsic viscosity (IV) (dL / g) was determined by dissolving the sample in a concentration of 0.25 g / 50 ml in a 60 wt% phenol solvent and a 40 wt% 1,1,2,2-tetrachloroethane solvent, The inherent viscosity of the sample was measured at 30 캜 using a Rheotek Glass Capillary viscometer according to ASTM D4603. Then, the intrinsic viscosity (dL / g) was calculated from the inherent viscosities measured using the following equations (2) and (3).

(In the above equation (2)

η _inh is the intrinsic viscosity,

ln is the natural logarithm,

t _s is the capillary penetration time of the sample,

t ₀ is the capillary penetration time of the solvent (blank),

C is the concentration in grams of sample per 100 ml of solvent).

(In Equation 3,

η is the intrinsic viscosity,

η _r is relative viscosity (= t _s / t ₀ ).

(3) Content of cyclic dimer and dipropylene glycol (DPG)

NMR measurement solvent [CDCl ₃ : TFA (Small Substitute) = 5: 1 volume ratio] After dissolving about 15 mg of sample in 1 ml, the mixed solution was transferred to an NMR tube, and then Bruker AVANCE Digital 300 MHz NMR instrument was used. Proton analysis of the samples was performed. Then, the content (wt%) of the cyclic dimer in the sample was calculated using Equation 4 below, and it was assumed that the specific gravity of the cyclic dimer and the specific gravity of the polyester (polytrimethylene terephthalate, PTT) were the same. In addition, the content (mol%) of DPG in the sample was calculated using Equation 5 below, wherein the protons located at both terminal carbons of 1,3-PDO in the polymer chain and the protons located at the carbon next to the ether group of the DPG. Quantitation was based on.

(In Equation 4,

A _c-dimer is the benzene ring peak area of cyclic dimer near 7.65 ppm,

A _ptt is the area of the benzene ring peak in PTT near 8.1 ppm).

(In Equation 5,

A _1,3-PDO is the area of the proton peak of 1,3-PDO terminal carbon in the polymer chain at 4.5 to 4.6 ppm,

A _DPG is the area of the proton peak located at the carbon next to the Ether group of the DPG in the polymer chain at 3.9 ppm).

(4) Acrolein and allyl alcohol content in condensate during liquid-phase polymerization

Condensate was analyzed under the following conditions using gas chromatography, and the relative sensitivity was quantified using butanol as a standard. The content of acrolein and aryl alcohol (ppm) was calculated using the following equations (6) and (7), respectively.

<Analysis condition>

1) column-INNOWAX 30 m,

2) inlet temperature-200 ℃,

3) Detector-FID detector (detector temperature: 280 ℃)

4) gas flow rate-3 ml / min,

5) Division diagram-10: 1,

6) Oven temperature-60 ℃ (maintained for 2 minutes) → heated up to 80 ℃ at a rate of 5 ℃ / min → heated up to 240 ℃ at a rate of 20 ℃ / min → 240 ℃ (maintained for 2 minutes)

(In Equations 6 and 7,

A _arcolein is the gas chromatograph (GC) area of acrolein,

A _allylalcohol is the GC area of allyl alcohol,

A _std is the GC area of the standard,

F ₁ is a GC sensitive factor of acrolein,

F ₂ is a GC sensitive factor of allyl alcohol).

&Lt; Example 1 >

1-1. Preparation of esterification reaction product

Stirrer for agitating the reactants, a packed column filled with a filler for refluxing 1,3-propanediol (1,3-PDO) into the reactor while removing the water produced during the esterification reaction, temperature sensor, and reactant 415.3 g of terephthalic acid and 247.3 g of 1,3-propanediol were added to a 1 L glass reactor equipped with an electric heating mantle for heating, and then the reaction temperature was gradually raised by applying heat while stirring in a nitrogen atmosphere. Thereafter, when the temperature of the reactant reached 200 ° C., 366 mg of titanium butoxide (Ti-OBu ₄ ) and 51.6 mg of magnesium hydroxide [Mg (OH) ₂ ] were added, and the reaction temperature was increased to 250 ° C. After the esterification reaction was carried out while raising the temperature, the reaction was terminated when the reaction product became transparent to obtain an esterification reaction product. The acid value, cyclic dimer, and dipropylene glycol (DPG) content of the resulting reaction product was measured.

1-2. Production of polyester

(1) Liquid Phase Polymerization

The esterification obtained in Example 1-1 in a 300 ml glass reactor equipped with a stirrer, a thermometer, a vacuum device, a collecting device for condensing and collecting gaseous by-products generated during the reaction, and an electric heating mantle for heating the reactor. 150 g of the reaction product was added and then slowly heated while stirring. When the reaction temperature reached 260 ° C., 48 mg of titanium butoxide (Ti-OBu ₄ ) was added as a reaction catalyst, and then vacuum was slowly added to 30 torr for 5 minutes, followed by preliminary liquid polymerization. Thereafter, vacuum was applied at 260 ° C. for 2 minutes to 0 torr, followed by liquid phase polymerization at 0 torr for 20 minutes to obtain a polyester in a molten state.

The obtained polyester in the molten state was put in distilled water at 20 ° C. to make a solid phase, and then analyzed for intrinsic viscosity (IV), acid value, cyclic dimer, and DPG content. In addition, the amount of condensate and acrolein and allyl alcohol that were generated during the polymerization process and removed out of the system were analyzed. The analysis results are shown in Table 1.

(2) solid state polymerization

The polyester in the molten state obtained in (1) of Example 1-2 was put in distilled water at 20 ° C. and solidified. Thereafter, the solidified polyester was made into pellets having a diameter of about 1.8 to 2.8 mm to obtain a polyester pellet. Thereafter, 2 g of the polyester pellets were placed in a solid-phase polymerization reactor, and then solid-state polymerization was carried out at 225 ° C. for 6 hours while injecting nitrogen at 30 ml / min. Polyester was obtained. At this time, a 1-inch tube (inner diameter: 10 mm, length: 30 cm) was used as the solid phase polymerization reactor, and an electric heater was installed on the outer wall of the reactor to control the temperature. After the reaction, the mixture was slowly cooled to room temperature to obtain a polyester.

The acid value, cyclic dimer, and DPG content of the polyester obtained above were analyzed. The results of the analysis are shown in Table 1.

<Example 2>

2-1. Preparation of Ester Reaction Products

The esterification reaction product was obtained in the same manner as in Example 1-1, except that 26 mg of NaOH was used instead of Mg (OH) ₂ used in Example 1-1.

2-2. Production of polyester

A polyester was obtained in the same manner as in Example 1-2, except that the liquid phase polymerization was carried out for 30 minutes instead of 20 minutes.

&Lt; Comparative Example 1 &

1-1. Preparation of Ester Reaction Products

The esterification product was obtained in the same manner as in Example 1-1, except that Mg (OH) ₂ used in Example 1-1 was not used.

1-2. Production of polyester

A polyester was obtained in the same manner as in Example 1-2, except that the liquid phase polymerization was performed for 15 minutes instead of 20 minutes.

Comparative Example 2

2-1. Preparation of Ester Reaction Products

In Example 1-1, instead of adding the entire amount of 1,3-PDO at the beginning of the esterification reaction, about 70% by weight of the total amount of 1,3-PDO was added at the beginning of the esterification reaction, and after 1 hour of reaction, Except for adding the remaining 30% by weight, it was carried out in the same manner as in Example 1-1 to obtain an esterification reaction product.

2-2. Production of polyester

Polyester was obtained in the same manner as in Example 1-2.

<Experimental Example 1>

The esterification reaction products obtained in Examples 1 and 2 and Comparative Examples 1 and 2 and the polyesters obtained after the liquid phase polymerization and the solid phase polymerization, respectively, were analyzed and shown in Table 1 below. In addition, the intrinsic viscosity of the polyesters obtained after the liquid-phase polymerization and the solid-phase polymerization of Examples 1 and 2 and Comparative Example 1, respectively, was measured and shown in FIG. 1.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Esterification product Acid value (meq / kg) 226 251 196 287 Cyclic dimer content (wt%) 1.7 1.7 1.68 1.7 DPG content (mol%) 1.15 1.28 2.4 2.9 Polyester After liquid phase polymerization IV (dL / g) 0.436 0.469 0.423 0.469 Condensate Volume (g) 8.4 9.0 8.6 8.7 Acrolein content (ppm) 13 20 51 52 Allyl Alcohol Content (ppm) 276 200 565 600 DPG content (mol%) 1.3 1.2 2.53 2.7 Cyclic Dimer Content (wt%) 2.45 2.59 2.51 2.5 After solid state polymerization IV (dL / g) 0.8 0.76  0.83 0.87 DPG content (mol%) 1.43 1.3 2.63 2.8 Cyclic Dimer Content (wt%) 0.79 0.84 0.8 0.9

As a result of the measurement, in the case of the esterification reaction product of Example 1-1, the content of DPG was lower than that of the esterification reaction product of Comparative Example 1-1.

In addition, in the case of the polyester obtained after the liquid phase polymerization and the solid phase polymerization in Example 1-2, the content of DPG was lower than that of the polyester obtained after the liquid phase polymerization and the solid phase polymerization in Comparative Example 1-2, The content of acrolein and allyl alcohol in water was also low.

From these measurement results, when alkali metals and / or alkaline earth metals are used in the esterification reaction according to the present invention, the production of DPG is suppressed and the content of DPG in the esterification reaction product is lowered. Even in the case of liquid phase polymerization and solid phase polymerization, the DPG content in the polyester is kept low, and the DPG content is reduced, thereby minimizing the content of acrolein and allyl alcohol in the condensate generated during liquid phase polymerization. I could confirm it.

In addition, as can be seen in Figure 1, Example 1 using Mg (OH) ₂ during the esterification reaction was faster than the polymerization reaction in the solid-phase polymerization than Example 2 using NaOH. From this, it was found that the esterification reaction in the presence of Mg is more advantageous in terms of the polymerization rate than the esterification reaction in the presence of Na.

Example 3 Preparation of Esterification Reaction Products

The esterification product was obtained in the same manner as in Example 1-1, except that 51.6 mg of MgO was used instead of Mg (OH) ₂ used in Example 1-1.

The acid value, cyclic dimer, and dipropylene glycol (DPG) content of the esterification product obtained above was measured. The measurement results are shown in Table 2 below.

Example 4 Preparation of Esterification Reaction Products

The esterification reaction product was obtained in the same manner as in Example 1-1, except that 51.6 mg of Ca (OH) ₂ was used instead of Mg (OH) ₂ used in Example 1-1.

The acid value, cyclic dimer, and dipropylene glycol (DPG) content of the esterification product obtained above was measured. The measurement results are shown in Table 2 below.

Example 5 Preparation of Esterification Reaction Products

The esterification product was obtained in the same manner as in Example 1-1, except that 51.6 mg of NaOH was used instead of Mg (OH) ₂ used in Example 1-1.

The acid value, cyclic dimer, and dipropylene glycol (DPG) content of the esterification product obtained above was measured. The measurement results are shown in Table 2 below.

Experimental Example 2

The esterification reaction products obtained in Examples 3 to 5 were analyzed and shown in Table 2 below.

After esterification Acid value (meq / kg) Cyclic dimer (wt%) DPG (mol%) Example 3 226 1.7 1.2 Example 4 197 1.69 2.0 Example 5 275 1.7 1.1

< Example  6>

6-1. Preparation of Ester Reaction Products

The esterification product (acid value: 195 meq) was obtained in the same manner as in the esterification reaction of Example 1-1, except that 26 mg of MgO was added instead of Mg (OH) ₂ during the esterification of Example 1-1. / Kg, cyclic dimer content: 1.6 wt%, DPG content: 1.8 mol%).

6-2. Production of polyester

Liquid phase polymerization of Example 1-2 (1) except that the liquid phase polymerization was carried out for 30 minutes instead of the liquid phase polymerization for 20 minutes in the liquid phase polymerization of Example 1-2 (1). The polyester was obtained in the same manner as in the following.

< Example  7>

7-1. Preparation of Ester Reaction Products

In the same manner as in Example 6-1, an esterification reaction product (acid value: 195 meq / Kg, cyclic dimer content: 1.6 wt%, DPG content: 1.8 mol%) was obtained.

7-2. Production of polyester

Liquid phase polymerization of Example 1-2 (1) except that the liquid phase polymerization was carried out for 70 minutes instead of the liquid phase polymerization for 20 minutes in the liquid phase polymerization of Example 1-2 (1). The polyester was obtained in the same manner as in the following.

< Example  8>

8-1. Preparation of Ester Reaction Products

In the same manner as in Example 6-1, an esterification reaction product (acid value: 195 meq / Kg, cyclic dimer content: 1.6 wt%, DPG content: 1.8 mol%) was obtained.

8-2. Production of polyester

In the liquid phase polymerization of Example 1-2 (1), except that the liquid phase polymerization reaction is performed for 100 minutes instead of performing the liquid phase polymerization reaction for 20 minutes, the liquid phase polymerization reaction of Example 1-2 (1) The polyester was obtained in the same manner as in the following.

&Lt; Comparative Example 3 &

3-1. Preparation of Ester Reaction Products

The esterification product (acid value: 196 meq / Kg, cyclic dimer content: 1.68 wt) was carried out in the same manner as in Example 1-1, except that Mg (OH) ₂ used in Example 1-1 was not used. %, DPG content: 2.4 mol%).

3-2. Production of polyester

Liquid phase polymerization of Example 1-2 (1) except that the liquid phase polymerization was carried out for 70 minutes instead of the liquid phase polymerization for 20 minutes in the liquid phase polymerization of Example 1-2 (1). The polyester was obtained in the same manner as in the following.

<Experimental Example 3>

The liquid polymerization products (polyester) obtained in Examples 6 to 8 and Comparative Example 3 were analyzed and shown in Table 3 below.

Liquid polymerization time
(minute) Liquid Phase Polymerization Result IV (dL / g) Condensate Volume (g) Acrolein content (ppm) Allyl Alcohol Content (ppm) DPG content
(mol%) Cyclic dimer
(wt%) Example 6 30 0.51 8.9 15 350 1.7 2.48 Example 7 70 0.6 9.2 20 411 1.7 2.46 Example 8 100 0.58 9.2 22 520 1.65 2.46 Comparative Example 3 70 0.62 9.2 53 736 2.6 2.55

As can be seen in Table 3, in the case of Example 7, the content of DPG in polyester was also low as 1.7 mol%, and the content of acrolein and aryl alcohol was low compared to Comparative Example 3. In addition, in the case of performing only the liquid phase polymerization reaction, the intrinsic viscosity did not increase significantly even if the polymerization time was increased.

Claims (12)

A process for preparing an esterification reaction product by esterifying dicarboxylic acid and 1,3-propanediol in the presence of a metal selected from the group consisting of alkali metals and alkaline earth metals. The method of claim 1,
Wherein the metal is selected from the group consisting of magnesium (Mg), calcium (Ca), potassium (K) and sodium (Na). The method of claim 1,
The metal is a method for producing an esterification reaction product, characterized in that it comprises 1 to 1000 ppm based on the total weight of the polyester after liquid polymerization. The method of claim 1,
Wherein the molar ratio of 1,3-propanediol to dicarboxylic acid is 1.0 to 2. The method according to any one of claims 1 to 4, characterized in that the esterification product contains up to 2 mol% of dipropylene glycol based on the total moles of diols in the esterification product. Process for preparing an esterification reaction product. The process of claim 1 wherein the intrinsic viscosity is from 0.05 to 0.4 dL / g. Esterifying dicarboxylic acid and 1,3-propanediol in the presence of a metal selected from the group consisting of alkali metals and alkaline earth metals to obtain esterification products; And
Liquid-polymerizing the esterification reaction product to form a polyester
Method for producing a polyester comprising a. The method of claim 7, wherein
In the liquid phase polymerization step of the esterification reaction product, characterized in that to obtain a polyester having an intrinsic viscosity of 0.3 to 0.65 dL / g. The method of claim 7, wherein
The polyester after the liquid polymerization is a method for producing a polyester, characterized in that the content of dipropylene glycol in a content of 2 mol% or less based on the total number of moles (mole) of the diol units included in the polyester after the liquid polymerization . According to claim 7, After the liquid phase polymerization of the esterification reaction product,
And solidifying the polyester formed by the liquid polymerization to solidify the polyester. The method of claim 10,
Method for producing a polyester, characterized in that in the solid phase polymerization step of the polyester to obtain a polyester having an intrinsic viscosity of 0.7 to 2 dL / g. The method of claim 10,
The polyester after the solid phase polymerization is a method for producing a polyester, characterized in that it contains dipropylene glycol in an amount of 2 mol% or less based on the total number of moles of diol units included in the polyester after the solid phase polymerization. .

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