KR20150023154A - Preparing methods of Polyester copolymer - Google Patents

Abstract

The present invention relates to a method for producing copolymer polyester for a binder by performing esterification and condensation polymerization on a dicarboxylic acid component consisting of 60-99 mole% of terephthalic acid, an ester-generating derivative of the same, or a mixture thereof and 40-1 mole% of isophtallic acid, an ester-generating derivative of the same, or a mixture thereof and a diol component consisting of 60-100 mole% of ethyleneglycol and 0-40 mole% of diethyleneglycol, wherein the method comprises a step of adding a thermal stabilizer before the esterification. The thermal stabilizer is a phosphorous-based thermal stabilizer and is preferable to be phosphoric acid, phosphorous acid, hypophosphoric acid, calcium phosphate, triethyl phosphate (TEP), or a mixture thereof. It is preferable that the phosphoric acid, phosphorous acid, hypophosphoric acid, calcium phosphate, triethyl phosphate (TEP), or mixture thereof is 1-1,500 ppm based on phosphorous for the total polymerized copolymer polyester. Also, it is preferable that 1-500 ppm of the calcium phosphate based on the total copolymer polyester is added. In the copolymer polyester of the present invention, the content of an isophtallic acid-ethyleneglycol ring-type dimer is 0.6 wt% or less based on the total weight of the finally polymerized copolymer polyester.

Description

[0002] Preparing methods of Polyester copolymer [

The present invention relates to a polyester-based binder fiber (composite fiber). More specifically, the present invention relates to a polyester-based binder fiber having a polyester-based binder fiber . The present invention also relates to a copolymerized polyethylene terephthalate having a low content of a cyclic dimer or ring dimer as a copolymerized polyester which is a low-melting-point component in a conjugated polyester-based binder fiber.

Nonwoven fabrics made of binder fibers are largely produced by two methods. One method is to coat the short fibers in order to impart adhesiveness, then dissolve a resin such as polyvinyl alcohol or acrylic resin in a solvent, and then apply the resultant to the surface of the nonwoven fabric for adhesion. The binder fibers prepared by composite spinning in an in-phase or sheath-core type or side-by-side type having a low melting point at a certain rate are mixed at the time of carding, and then the constituent fibers are bonded by heat treatment.

However, the method of dissolving the polyvinyl alcohol or acrylic resin, which is the former method, in a solvent does not penetrate deeply into the inside of the web but also causes environmental contamination by the solvent and low compatibility with the polyester which is a matrix Therefore, it is limited to use only for a garment wick which simply bonds the surface of a nonwoven fabric. Also, it has a disadvantage that it is not applicable to a product having a low adhesiveness and rough feel and high strength. In addition, the organic solvent used is highly volatile and harmful to the human body, and when it is used as a nonwoven fabric for molding, it is pointed out that a solvent and a resin are buried in the mold.

The latter method has a great advantage that adhesion is instantaneously completed by heating in a solvent-free manner. In the field of fiber bonding, too, many products have been developed and commercialized since they contribute greatly to the rationalization of the bonding process, the reduction of personnel, and the speeding up of the bonding process.

As a problem in the synthesis of an ester derivative using the latter thermally fusible binder fiber comprising terephthalic acid and isophthalic acid as a dicarboxylic acid component, a cyclic oligomer compound having a polymerization degree of 2 (cyclic dimer Or ring dimer is reported.

[Chemical Formula 1]

The present invention relates to a low melting-point copolymer polyester obtained by condensation polymerization of terephthalic acid and isophthalic acid as diol components with ethylene glycol as an diacid component, and is characterized in that an oligomer which acts as a foreign substance in a yarn spinning process at a melting point higher than that of the polymer, It is aimed to reduce the content of the isophthalic acid-ethylene glycol cyclic dimer [Formula 1].

Since the melting point of the cyclic dimer is about 325 ° C, it is higher than the polymerization temperature of a general polyester, so that it does not melt during polymerization and tends to act as a foreign substance to shorten the period of filter replacement to lower the productivity. It is required to reduce the generation of oligomers in order to improve the work environment and improve the fairness.

U.S. Patent Nos. 4,418,188 and 4,065,439 disclose techniques for reducing the production rate of the cyclic oligomer of Chemical Formula 1 through the use of an acid compound such as sulfuric acid in the polymerization of polyethylene isoterephthalate, but the acidity of the acid compound is strong Problems such as corrosion of the polymerization equipment occur during the process operation.

The present inventors have developed a copolymerized polyethylene terephthalate having a low cyclic dimer in order to solve the above problems, and developed conjugated fibers using the same.

It is an object of the present invention to provide a copolymerized polyethylene terephthalate having a low content of cyclic dimer by reducing the production of a cyclic dimer in the production of a low melting point copolymer polyester.

Another object of the present invention is to provide a process for producing a low melting point copolymer polyester by reducing the generation of a cyclic dimer and lowering the pressure rise of the polymer filter to extend the filter replacement cycle and reduce the number of times of refolding during the binder fiber spinning process, To provide a novel method for producing copolymerized polyethylene terephthalate having a low content of cyclic dimers capable of reducing the process cost by improving the spinning processability.

Another object of the present invention is to provide a conjugated fiber having improved quality by using a copolymerized polyethylene terephthalate having a low content of cyclic dimer.

These and other objects of the present invention can be achieved by the present invention which is described in detail below.

The present invention relates to a dicarboxylic acid component comprising 60 to 99 mol% of terephthalic acid, an ester forming derivative thereof, or a mixture thereof, and 40 to 1 mol% of isophthalic acid, an ester forming derivative thereof, A method for producing a copolymerized polyester for a binder by esterifying a diol component comprising 0 to 40 mol% of ethylene glycol and 0 to 40 mol% of diethylene glycol, .

The thermal stabilizer is preferably phosphoric acid, phosphorous acid, charyophosphoric acid, calcium phosphate, triethyl phosphate (TEP) or a mixture thereof as the phosphorus thermal stabilizer. Phosphoric acid, phosphorous acid, hypophosphorous acid, calcium phosphate, triethyl phosphate (TEP), or a mixture thereof is preferably added in the range of 1 to 1,500 ppm based on phosphorus with respect to the entire polymerized copolymer polyester.

The copolymer polyester of the present invention produced by the above method is characterized in that the content of the isophthalic acid-ethylene glycol cyclic dimer of the following formula (1) is polymerized to 0.6 wt% or less based on the total weight of the copolymerized polyester finally polymerized .

[Chemical Formula 1]

The copolymer polyester of the present invention produced according to the above method is a copolymerized polyester having a low melting point and is a copolymerized polyester obtained by using polyethylene terephthalate as a high melting point component and a copolymerized polyester of the present invention as a low melting point component, Based binder fibers. This binder fiber can be produced by composite spinning of the polymer of the present invention and a general polyethylene terephthalate polymer in a sheath-core type or a side-by-side manner.

Hereinafter, the present invention will be described in detail.

The present invention provides a copolymerized polyethylene terephthalate having a low content of a cyclic dimer by reducing the production of a cyclic dimer in the production of a low melting point copolymer polyester and reducing the generation of a cyclic dimer in the production of a low melting copolymer polyester, Lowering the cyclic dimer to lower the pressure rise of the filtration filter to extend the filter replacement cycle, reduce the number of yarn splices during the spinning process of the binder fibers, The present invention provides a novel method for producing a copolymerized polyethylene terephthalate having a high molecular weight.

TECHNICAL FIELD The present invention relates to a polyester-based binder fiber (composite fiber), and relates to a polyester-based binder fiber that is commonly spin-coated with polyethylene terephthalate as a high melting point component and a crystalline copolymer polyester as a low melting point component. The present invention also relates to a copolymerized polyethylene terephthalate having a low content of a cyclic dimer or ring dimer as a copolymerized polyester which is a low-melting-point component in a conjugated polyester-based binder fiber.

The present invention relates to a dicarboxylic acid component comprising 60 to 99 mol% of terephthalic acid, an ester forming derivative thereof, or a mixture thereof, and 40 to 1 mol% of isophthalic acid, an ester forming derivative thereof, A method for producing a copolymerized polyester for a binder by esterifying a diol component comprising 0 to 40 mol% of ethylene glycol and 0 to 40 mol% of diethylene glycol, .

The esterification reaction of the present invention can be carried out by mixing an oligomer composed of terephthalic acid and ethylene glycol with isophthalic acid and diethylene glycol.

The thermal stabilizer is preferably phosphoric acid, phosphorous acid, charyophosphoric acid, calcium phosphate, triethyl phosphate (TEP) or a mixture thereof as the phosphorus thermal stabilizer. Phosphoric acid, phosphorous acid, hypophosphorous acid, calcium phosphate, triethyl phosphate (TEP), or a mixture thereof is preferably added in the range of 1 to 1,500 ppm based on phosphorus with respect to the entire polymerized copolymer polyester.

In the polymerization process, it is preferable that the antimony-based catalyst is carried out in an amount of 100 to 500 ppm based on the metal antimony and the melt polymerization temperature is in the range of 255 to 285 캜 based on the weight of the final polymer. As the antimony catalyst, antimony trioxide (ATO) or antimony triglycolate (ATG) catalyst may be added in an amount of 100 to 350 ppm based on the antimony content, or a known polycondensation catalyst may be added.

Thermal stabilizers, including phosphorus compounds, are used for the purpose of preventing deterioration and improving processing performance in polymer polymerization and are used in the production of various polymers including polyethylene terephthalate. If an appropriate heat stabilizer is not added, melt viscosity changes due to mechanical shear force and oxidation due to the cleavage of the main chain of the polymer, resulting in unstable processing conditions, resulting in product coloration and deterioration of properties. Phosphorus thermal stabilizers capture and inactivate ROOH or radicals that cleave the polymer backbone and serve to stabilize the coordination of catalyst residues and transition metal impurities, or to remove the activity of the oxidation catalyst.

40 or 80 ppm of triethyl phosphate (TEP), phosphoric acid [H3PO4], phosphorous acid [H3PO3], phosphorous acid [H3PO2] and calcium phosphate [Ca3 (PO4) 2] The content of cyclic dimer was measured by oligomer content and NMR analysis. The content of the oligomer is preferably 6.0 wt% or less, more preferably 4.0 wt% or less. The content of the cyclic dimer is intended to be reduced to 0.6 wt% or less. The oligomer acts as an impurity in the spinning process to increase the pressure of the filter quickly and frequently, thereby causing frequent filter replacement cycles and precipitation in the form of needle-like oligomer, which causes difficulties in the process. Also, the yield is reduced by increasing the number of yarn splicing due to quality degradation. Therefore, the above-mentioned oligomer reduction has the effect of reducing the cost by improving the quality and improving the fairness as well as improving the quality.

(2)

NMR analysis showed that the amount of dimer in the actual process was 0.47 in ES-1, 0.48 in ES-2, 0.70 in PC reaction, and the amount of dimer produced in ES-1 reaction was larger than that of dimer Is considered to be more. Therefore, it was possible to reduce the oligomer content by adding phosphorus thermal stabilizer, which was mainly added to the conventional PC reaction, before the ES reaction. In other words, when the stabilizer is added to the ES reaction rather than to the PC reaction, the effect of reducing the cyclic dimer oligomer can be observed.

As a result, it was found that the addition of the acid and calcium phosphate significantly reduced the oligomer content, and the number of trimerization and yield could be quantified. And the fairness was improved. As the total number of unfired yarns per yarn weight, the yarn yield is calculated by the ratio of yarn waste that is refracted during the yarn spinning process. As the number of yarn yarns increases, the unevenness occurs frequently and quality deteriorates.

The copolymer polyester of the present invention produced by the above method is characterized in that the content of the isophthalic acid-ethylene glycol cyclic dimer of the following formula (1) is polymerized to 0.6 wt% or less based on the total weight of the copolymerized polyester finally polymerized .

[Chemical Formula 1]

The copolymer polyester of the present invention produced according to the above method is a copolymerized polyester having a low melting point and is a copolymerized polyester obtained by using polyethylene terephthalate as a high melting point component and a copolymerized polyester of the present invention as a low melting point component, Based binder fibers. This binder fiber can be produced by composite spinning of the polymer of the present invention and a general polyethylene terephthalate polymer in a sheath-core type or a side-by-side manner.

Hereinafter, the present invention will be described more specifically with reference to the following examples, but the scope of protection of the present invention is not limited to these examples.

Example  One

Terephthalic acid and ethylene glycol are added to the ester reaction tank and reacted at a temperature of 258 ° C by a conventional method to prepare an oligomer having a reaction rate of 96%. To the oligomer, isophthalic acid and diethylene glycol, which are copolymerization components, are added. Prior to the esterification reaction (ES), triethyl phosphate (TEP) as a heat stabilizer was added at 40 ppm of the final polymer. Diethylene glycol is added together with a conventional ester reaction catalyst so that the addition amount of the isophthalic acid component is 1 to 40 mol% in the final copolymerized polyester composition and 0 to 40 mol% based on the final copolymerized polyester molar amount, The esterification reaction proceeds for 1 hour. After the polycondensation reaction catalyst was added to the esterified oligomer thus obtained, the polycondensation reaction (PC) was carried out by gradually raising the temperature to 280 DEG C while gradually reducing the pressure to 0.1 mmHg. The physical properties and composition of the copolyester chips produced under the above conditions were measured, and the measurement results of each example are shown in Table 1. Finally, a sheath-core type polyester-based binder fiber having a single-fiber fineness of 4 denier was prepared using a conventional polyether terephthalate chip as a core component as a sheath component, The number of times and the yield are also shown in Table 1.

Example  2

Esterification (ES) The same procedure as in Example 1 was repeated, except that 40 ppm of the final polymer was added as the thermal stabilizer. The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

Example  3

Esterification (ES) The same procedure as in Example 1 was repeated, except that 40 ppm of calcium phosphate was added as a thermal stabilizer. The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

Example  4

Esterification reaction (ES) The same procedure as in Example 1 was repeated except that 80 ppm of calcium phosphate was added as a thermal stabilizer. The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

Comparative Example  One

The same procedure as in Example 1 was repeated except that 40 ppm of the final polymer was added as the heat stabilizer before the polycondensation reaction (PC). The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

Comparative Example  2

Polycondensation reaction (PC) The same procedure as in Example 1 was repeated except that phosphoric acid as the thermal stabilizer was added at 40 ppm of the final polymer. The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

Comparative Example  3

Polycondensation reaction (PC) The same procedure as in Example 1 was repeated, except that 40 ppm of the final polymer was added as the thermal stabilizer. The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

Comparative Example  4

The same procedure as in Example 1 was repeated, except that 80 ppm of the final polymer was added as a heat stabilizer before the polycondensation reaction. The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

Comparative Example  5

The same procedure as in Example 1 was repeated except that no heat stabilizer was added.

Comparative Example  6

The same procedure as in Example 1 was repeated except that 40 ppm of TEP was added as a heat stabilizer before the polycondensation reaction. The physical properties and composition were measured, and the measurement results of this example are shown in Table 1.

[Table 1]

As can be seen from the results of Table 1, in Comparative Example 5 in which no heat stabilizer was added, a slightly higher proportion of the oligomer and the cyclic dimer contained therein could be confirmed, Comparing Example 2, Example 1 and Comparative Example 6, it was found that the addition of the heat stabilizer to the PC reaction before the ES reaction was effective in reducing the oligomer content. When the amount of oligomer and cyclic dimer was particularly low, calcium phosphate was added to the final polymer in an amount of 80 ppm based on the final polymer, and oligomer and dimer contents were about 1 wt%, respectively, as compared with Comparative Example 6, 0.16 wt%. The generation of needle oligomers was remarkably reduced, and the fairness was slightly improved by reducing the number of filing cycles and increasing the yield.

The evaluation items shown in the above Examples and Comparative Examples were measured in the following manner.

* Measurement of oligomer weight%: About 2.5 g of polymer pellets are pulverized and dissolved in chloroform for 4-5 hours. Methanol is then added to precipitate the polymer and the oligomer to dissolve in the solution. Only the solution was collected separately, evaporated and the weight of oligomers remaining in the vessel was measured.

* Measurement of cyclic dimer weight%: The copolymerized polyester was dissolved in trifluoroacetic acid and analyzed by a proton nuclear magnetic resonance apparatus (1 H NMR) (model: DRX- 300).

Determination of intrinsic viscosity (IV): Copolymer polyester was dissolved in phenol / tetrachloroethane (weight ratio 50/50) to make a 0.5 wt% solution and measured at 35 캜 with a Uvold viscometer.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

60 to 99 mol% of terephthalic acid, an ester forming derivative thereof, or a mixture thereof, and 40 to 1 mol% of isophthalic acid, an ester forming derivative thereof, or a mixture thereof; A process for producing a copolymer polyester for a binder by esterifying a diol component comprising 60 to 100 mol% of ethylene glycol and 0 to 40 mol% of diethylene glycol,
Wherein the heat stabilizer is added before the esterification reaction.
The process according to claim 1, wherein the heat stabilizer is phosphoric acid, phosphorous acid, charyophosphoric acid, calcium phosphate, triethyl phosphate (TEP) or a mixture thereof.
The binder according to claim 2, wherein the phosphoric acid, phosphorous acid, charyophosphoric acid, calcium phosphate, triethyl phosphate (TEP) or a mixture thereof is 1 to 1,500 ppm based on phosphorus with respect to the entire polymerized copolyester Wherein the copolymer is a polyester.
A binder produced according to any one of claims 1 to 4, wherein the content of the isophthalic acid-ethylene glycol cyclic dimer of the following formula (1) is 0.6 wt% or less based on the total weight of the copolymerized polyester finally polymerized Copolymer polyester for use in the present invention:

[Chemical Formula 1]

The polyester-based binder fiber according to claim 5, wherein the polyethylene terephthalate is a high melting point component and the copolymerized polyester for a binder according to claim 5 is a low melting point component.
The polyester binder according to claim 6, wherein the polyester-based binder fiber is produced by composite spinning in a sheath-core type or a side-by-side manner. fiber.