KR20010063964A - Process for preparing a polyethylene naphtalate polymer for the yarn of the industrial use - Google Patents

Abstract

PURPOSE: Provided is a method for preparing a polyethylenenaphthalate polymer which is proper to produce highly strong yarn having a strength of more than 9.0 gram per denier by increasing a crystallization speed, for an industrial use. CONSTITUTION: In preparing the polyethylene naphthalate by an ester exchange reaction and a polycondensation reaction of naphthalene dicarboxylate and diol, more than 100 part per million of titanium dioxide, which is a nucleating agent of a crystal, is added to one mol of naphthalene dicarboxylate.

Description

Process for preparing a polyethylene naphtalate polymer for the yarn of the industrial use}

The present invention relates to a method for producing a polyethylene naphtalate (PEN) polymer for industrial manufacture.

More specifically, the present invention relates to a method for producing PEN polymers used to prepare polyethylene naphthalate (PEN) having a strength of 9.0 g / denier or more.

Recently, polyethylene terephthalate (PET) resin is being replaced by PEN to supplement the required physical properties as the weight of the product, high performance, high heat resistance and the like is required.

PEN adopts a rigid phthalate ring structure instead of the benzene ring of PET, which is very similar in structure to existing PET, but has mechanical properties such as glass transition temperature, heat resistance, tensile strength, and creep resistance. Compared to PET, the gas barrier property is more than 5 times superior to PET, and thus it is widely used in high strength thin film films, gas barrier bottles, barrier bottles, and heat-resistant containers.

In particular, the properties of PEN is suitable as a reinforcing material for belts and hoses that require high strength and high heat resistance, and can exhibit optimal physical properties for tire cords.

Conventional techniques for producing such PEN polymers include Japanese Patent Laid-Open Nos. 62-143938, Hei 6-56975, Hei 6-293825, Hei 7-82465, Hei 8-169940, Hei 9-77859 And US Pat. Nos. 5,350,829 and 5,294,695.

Japanese Laid-Open Patent Publication No. 62-143938 proposes a method for synthesizing a polymer to increase the yarn strength of PEN by reducing the concentration of carboxyl end groups by preventing thermal decomposition of PEN by adding a heat stabilizer.

Hei 6-56975 describes a PEN composition having a carboxyl group terminal concentration of 40 equivalents / 10 ⁶ gr or less and a diethylene glycol content of 1.3% by weight or less.

However, the PEN polymer has a high melt viscosity, so that the PEN polymer should be spun at a high temperature of 10 ° C. or more above the melting temperature during spinning.

Hei 6-293825 and Hei 7-82464 describe a method for producing PEN polymers having excellent transparency, thermal stability, surface flatness and curl resolution by adjusting the amount of reaction catalyst.

8-169940 is a transesterification reaction of NDC (Naphthalene dicarboxylate) and diol (diol) in the transesterification reaction and polycondensation reaction in the production of PEN, 0.1 to 0.5% by weight of the transesterification catalyst to the weight of NDC during the transesterification reaction And a polycondensation reaction catalyst of 0 to 0.04% by weight of NDC during the electrical polycondensation reaction was described.

Hei 9-77859 describes a PEN process with good color and transparency.

U.S. Patent No. 5,350,829 uses glycol soluble compounds such as magnesium, manganese and zinc as catalysts, and the molar ratio of NDC and EG is 1: 1.05 to 1: 2.5, and the esterification temperature is 240 to 330 ° C and the pressure is 5 Kg / cm <2> and polycondensation describe the method of advancing under reduced pressure 270-330 degreeC.

U.S. Patent No. 5,294,695 is a high viscosity PEN polymerization method which is prepared in a two step process using NDC and EG, in which one step is reacted at 500 to 30 torr and the second to 10 to 0.1 torr pressure I'm making it.

At this time, the intrinsic viscosity of the generated PEN is 0.4 ~ 1.0dl / g.

PEN manufactured by the conventional methods as described above has a limitation in manufacturing a high strength yarn, there is a disadvantage that the manufacturing process is complex.

The present invention aims to provide a method for producing PEN polymers suitable for high strength yarns by increasing the rate of crystallization.

In the present invention, in the preparation of PEN by transesterification and polycondensation reaction of naphthalene dicarboxylate (NDC) and diol, a transesterification catalyst using 100 ppm or more of ester exchange reaction with respect to the number of moles of NDC during the transesterification reaction, The polycondensation reaction catalyst of 200ppm or more was used, 50ppm or more of heat stabilizer was added during the polycondensation reaction, and a catalyst to be used as a nucleating agent was added to form a crystal of the polymer.

Hereinafter, the present invention will be described in detail.

The inventors have found that the amount of catalyst used as a crystallization nucleating agent affects the strength of the fiber produced in the production of PEN fibers by producing PEN polymers containing 90 mol% or more of NDC units and having an intrinsic viscosity of 0.3 to 1. I confirmed the fact.

In the present invention, a manganese (Mn) compound which is a transesterification catalyst of 100 ppm or more relative to the number of moles of NDC in the transesterification reaction was used, the reaction temperature was carried out at 190 ~ 240 ℃, the polycondensation reaction catalyst Sb ₂ 200 ppm or more of O ₃ compounds were used, and the reaction temperature was carried out at 240 to 290 ° C.

In the present invention, trimethylene phosphate as a heat stabilizer was added during polycondensation reaction up to 50 ppm to 300 ppm with respect to the NDC mole number, and titanium dioxide (TiO ₂ ) as the nucleating agent was 100 to 1000 ppm or less with respect to the NDC mole number, respectively, and 1001 ppm to 3000 ppm and 3001 ppm or more were added by NDC melting.

When the fiber was prepared from the polymer prepared as described above, two-stage stretching was performed.

50 to 95% of the total draw ratio was first stretched, followed by second to 5 to 50% stretching, and the temperature of each roller heated the second and third stretching rollers above the glass transition temperature of PEN. Stretching was performed, and in particular, the fourth and fifth stretching rollers were set in the range of 150 to 250 ° C. and 120 to 220 ° C., respectively, so that heat setting and orientation crystallization were completed.

Since the crystallization rate of PEN is considerably lower than that of PET, the crystallization rate can be increased by adding a nucleating agent in the present invention.

The polymer without addition of the nucleating agent has a semicrystallization time of 7 minutes or more, whereas the polymer with 100 to 1000 ppm added to the NDC molar number has a semicrystallization time of 5 to 7 minutes, and the semicrystallization time of the polymer to which 1001 ppm to 3000 ppm or less is added. Is 3 to 5 minutes.

In addition, the semicrystallization time of the polymer to which 3001 ppm or more was added is 3 minutes or less, and it can be seen that the crystallization rate of the PEN polymer is increased when the nucleating agent is added to 100 ppm or more.

Yarn produced as described above has excellent mechanical properties and thermal stability as a reinforcing agent of various rubber products such as tires.

Example 1

The thermal stabilizer trimethylene phosphate was added during the 200ppm polycondensation reaction with respect to the number of moles of NDC, and titanium dioxide as the nucleating agent was added during the melting of NDC with 700ppm with respect to the mole of NDC.

With respect to the number of moles during the ester exchange reaction of NDC was used for the manganese compound 290ppm or more ester-exchange reaction catalyst, the reaction temperature, a polycondensation reaction catalyst is Sb ₂ O ₃ compound of 380ppm when the polycondensation reaction was carried out at 190 ~ 240 ℃ The reaction temperature was used at 240-290 degreeC.

The polymer prepared as described above was subjected to solid phase polymerization to increase the viscosity, which was spun and then subjected to two-stage stretching.

The physical properties of the prepared yarn are shown in Table 1.

Comparative Example 1

Except for not adding a heat stabilizer and a nucleating agent is the same as in Example 1, the results obtained are shown in Table 1.

Comparative Example 2

Except for not adding a nucleating agent is the same as in Example 1, the results obtained are shown in Table 1.

<Table 1>

Example 1 Comparative Example 1 Comparative Example 2 Polymer Viscosity (Ⅳ) 0.85 0.85 0.85 Thermal Stabilizer (Wtppm) 200 0 200 TiO ₂ (Wtppm) 700 0 0 Sb ₂ O ₃ (Wtppm) 380 380 380 Yarn Total draw ratio 6.0 5.4 6.0 Strength (g / d) 9.4 8.2 9.2 Elongation (%) 8.1 7.8 8.3 Shrinkage (%) 4.0 4.1 4.3

Example 2

Except for the addition of 2000ppm nucleating agent was the same as in Example 1, the results obtained are shown in Table 2.

Comparative Example 3

Except that 50ppm was added to the nucleating agent is the same as in Example 2, the results are shown in Table 2.

<Table 2>

Example 2 Comparative Example 3 Polymer Viscosity (Ⅳ) 0.85 0.85 Thermal Stabilizer (Wtppm) 200 200 TiO ₂ (Wtppm) 2000 50 Sb ₂ O ₃ (Wtppm) 380 380 Yarn Total draw ratio 6.0 6.0 Strength (g / d) 9.8 9.0 Elongation (%) 7.5 7.8 Shrinkage (%) 3.8 4.1

Example 3

Except that 3500ppm was added to the nucleating agent is the same as in Example 1, the results obtained are shown in Table 3.

<Table 3>

Example 3 Polymer Viscosity (Ⅳ) 0.85 Thermal Stabilizer (Wtppm) 200 TiO ₂ (Wtppm) 3500 Sb ₂ O ₃ (Wtppm) 380 Yarn Total draw ratio 6.0 Strength (g / d) 9.1 Elongation (%) 7.8 Shrinkage (%) 3.7

The present invention can shorten the crystallization rate of the PEN polymer by a simple addition of a nucleating agent when preparing a polyethylene naphthalate (PEN) polymer, so that PEN yarn of high strength (9.0 g / d or more) can be produced without causing thermal decomposition. PEN polymer can be prepared.

Claims (1)

In preparing polyethylene naphthalate (PEN), polyethylene naphthalate for industrial manufacture is prepared by adding titanium dioxide (TiO ₂ ), which is a nucleating agent of crystals, by adding 100 ppm or more to the mole number of naphthalene dicarboxylate (NDC). Method for producing a polymer.