KR20070071190A - High tenacity polyethylene-2 ,6-naphthalate fiber - Google Patents

Abstract

A polyethylene naphthalate fiber, a method for manufacturing the same, and a method for manufacturing a polyethylene naphthalate polymer are provided to improve heat stability, dimension stability, and high tenacity of the polyethylene naphthalate fiber, by using a cocatalyst composed of an antimony catalyst, a titanium catalyst, and a heat stabilizer. In polymerizing polyethylene-2,6-naphthalate containing ethylene-2,6-naphthalate units of more than 85 mol%, antimony catalyst has a content of 40-150 ppm based on antimony metal and titanium has a content of 5-50 ppm based on the titanium metal. The polyethylene-2,6-naphthalate is melt-polymerized to have an intrinsic viscosity of 0.4-0.75 dl/g by using co-catalyst where a heat stabilizer has a content of 5-50 ppm based on a content of phosphorous. The melt-polymerized compound is solid-state polymerized to have an intrinsic viscosity of 0.7-1.20 dl/g. The solid-state polymerized compound is melt-spun to produce a melt release yarn. The melt release yarn passes through a delay cooling section and a cooling section to solidify an undrawn yarn. The solidified undrawn yarn is wound. The wound yarn is multistage-drawn.

Description

High tenacity polyethylene-2, 6-naphthalate fiber

The present invention relates to a polyethylene-2,6-naphthalate polymer having excellent reactivity and thermal stability using a novel cocatalyst system and a method for preparing a high strength polyethylene-2,6-naphthalate fiber prepared therefrom. The polyethylene naphthalate fiber produced is excellent in thermal stability, dimensional stability, high strength, high strength, and is suitable for industrial use of tires, belts, hoses, and rubber reinforcing materials.

Antimony is mainly used as a polymerization catalyst of polyethylene-2,6-naphthalate, but antimony catalyst has a disadvantage of causing cohesion under spinneret to reduce elongation at spinning. In order to overcome these disadvantages, Japanese Laid-Open Patent Publication No. 58-38,722 used a titanium catalyst and phosphite, a phosphorus-based compound, was used to compensate for the thermal stability, which is a disadvantage of the titanium catalyst, but did not improve the inherent color of titanium.

In addition, WO 01-0070 No. 6 was prepared by reacting a phosphorus compound with a titanium catalyst to form a complex, and added with additives such as trimellitic acid to improve the coloring problem of the titanium catalyst.

In addition, WO 01-14448 uses aluminum and phosphorus compounds to produce fibers having better stretchability than antimony catalysts.

However, each method has a disadvantage in that the manufacturing process is complicated and expensive.

The present invention has been made to solve the problems of the prior art as described above, by synergistically using the antimony catalyst and titanium catalyst in the polyethylene naphthalate melt polymerization step to complement the disadvantages of both catalysts and By adding thermal stabilizer of formula (1) which can complement the thermal stability, it gives thermal stability and prevents thermal decomposition in extruder etc. The purpose is to prevent the physical properties of the fiber from deteriorating.

Structural Formula (1)

(R ₁ : -OH, R _{2 to} R ₅ : C _n H _{2n +1} , provided that n = 0 to 5 and R _{1 to} R ₃ Is a substituent of Ph.)

(A) Intrinsic viscosity using a cocatalyst system composed of antimony, titanium and a heat stabilizer in the polymerization step of polyethylene-2,6-naphthalate containing 85 mol% or more of ethylene-2,6-naphthalate units Melt polymerizing in the range of 0.40 dl / g to 0.75 dl / g; (B) solid-phase polymerization of polyethylene-2,6-naphthalate with an intrinsic viscosity in the range of 0.70 dl / g to 1.20 dl / g; (C) winding the solidified unstretched yarn by passing the molten yarn produced by melt spinning the solid-state polymerized chip through a delay cooling and cooling zone; And (D) provides a method for producing a strong polyethylene-2,6-naphthalate fiber comprising the step of multi-stretching the wound undrawn yarn.

The present invention is characterized in that the new cocatalyst of step (A) is composed of antimony, titanium, and a heat stabilizer.

In addition, the present invention is characterized in that the content of the antimony catalyst is 40 to 150ppm in the polyethylene naphthalate polymer based on the antimony metal.

In addition, the present invention is characterized in that the content of the titanium catalyst is 5 to 50ppm in the polyethylene naphthalate polymer based on the titanium metal.

In addition, the present invention is characterized in that the chemical structural formula of the thermal stabilizer is the same as the formula (1), the content is 5 to 50ppm in the polyethylene naphthalate polymer based on the content of phosphorus.

In addition, the present invention provides a cocatalyst system composed of antimony and titanium in the polymerization step of polyethylene-2,6-naphthalate containing 85 mol% or more of ethylene-2,6-naphthalate units and the heat stabilizer of formula (1). It provides a method of producing a polyethylene naphthalate polymer, characterized in that the melt viscosity in the range of 0.4 to 0.75 dl / g using.

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

The polyethylene naphthalate chip used in the present invention contains at least 85 mol% of ethylene-2,6-naphthalate units and preferably consists only of ethylene-2,6-naphthalate units. Optionally, the polyethylene-2,6-naphthalate may incorporate as a copolymer unit small amounts of units derived from one or more ester-forming components other than ethylene glycol and 2,6-naphthalene dicarboxylic acid or derivatives thereof. Can be. Examples of other ester forming components copolymerizable with polyethylene naphthalate units include glycols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and the like, terephthalic acid, isophthalic acid, hexahydroterephthalic acid and dibenzoic acid. Dicarboxylic acids such as adipic acid, sebacic acid, and azelaic acid.

The polyethylene naphthalate chip according to the present invention is preferably a mixture of solids or melts of naphthalene-2,6-dimethylcarboxylate or carboxylic acid derivatives thereof and ethylene glycol raw materials at 190 ° C in a ratio of 1.6 to 2.2, followed by heating Naphthalene dicarboxylate and ethylene glycol at atmospheric pressure in the presence of a transesterification catalyst of 10 to 100 ppm of Zn, Mn, Mg, Pb, Ca, Co and the like with respect to the number of moles of naphthalene 2,6-dicarboxylate And a transesterification reaction to produce bishydroxy ethyl naphthalate or an oligomer having a degree of polymerization of 10 or less by reacting at a temperature of 180 to 240 ° C. Secondly, an antimony catalyst is 40 to 150 ppm based on antimony metal as a polymerization catalyst. 5 to 50 ppm of titanium catalyst is used on the basis of titanium, and the content of 5 to 50 ppm on the basis of phosphorus Stable compound is added alone or in combination with a conventional heat stabilizer

Structural Formula (1)

(R ₁ : —OH, R _{2 to} R ₅ : C _n H _{2n + 1} , provided that n = 0 to 5 and R _{1 to} R ₃ are substituents of Ph.)

After the condensation polymerization at 250 to 300 ℃ in vacuum for about 2 to 3 hours to produce a raw chip of the intrinsic viscosity 0.40 dl / g to 0.75 dl / g, and then the temperature and vacuum of 225 to 260 ℃ Solid phase polymerized to have an intrinsic viscosity of 0.70 dl / g to 1.20 dl / g and a moisture content of 30 ppm or less. If the intrinsic viscosity of the low chip is 0.40 dl / g or less, the solid-state polymerization time is excessively long, and the physical properties are deteriorated. When the intrinsic viscosity is 0.75 dl / g or more, pyrolysis occurs. If the intrinsic viscosity of the solid-state polymerization chip is less than 0.7 dl / g does not express the desired strength, if it exceeds 1.20 dl / g, the workability is worse.

In the cocatalyst system, the antimony catalyst is preferably 40 to 150 ppm based on the antimony metal. When the content of the antimony catalyst is less than 40 ppm, there is no effect of reactivity, and the content of titanium increases to cause pyrolysis and yellow coloration, and 150 ppm. If it exceeds, thermal curvature occurs and elongation deteriorates. The titanium catalyst is preferably 5 to 50 ppm based on titanium, and when the content of the titanium catalyst is less than 40 ppm, there is no reactivity effect and the antimony content increases to cause thermal degradation, deterioration in ductility, and pyrolysis when exceeding 150 ppm. And yellow coloration occur. The heat stabilizer is preferably used alone or in combination with a conventional heat stabilizer of the thermal stability compound of formula (1). In addition, the content of the thermal stabilizer is preferably 5 to 50 ppm based on the content of phosphorus, and when the thermal stabilizer content is less than 5 ppm, the effect of thermal stability is lowered, and when it exceeds 50 ppm, it acts as a foreign substance, thereby deteriorating physical properties and radioactivity. do.

In addition, examples of the conventional thermal stabilizer include phosphoric acid, trimethyl phosphate, triethyl phosphate, and the like.

In the production of polyethylene naphthalate polymers, when antimony catalysts are used alone, aggregates of catalysts gradually accumulate under spinneret, and the accumulated aggregates cause unevenness in the temperature gradient on the surface of the caps, resulting in deterioration of the ductility of the fibers. Will appear. When the titanium catalyst is used alone, the reactivity is excellent, but due to its unique thermal decomposition, severe yellow coloration occurs, and there is a disadvantage in that the viscosity decreases during processing. When using an appropriate amount of antimony catalyst and titanium catalyst as in the present invention, the disadvantages of the two catalysts are complied with, and at this time, the content of the antimony catalyst has a critical amount of very small accumulation of aggregates even in a long spinning process. The addition of antimony will reduce the amount of titanium titanium catalyst required, and the coloring and viscosity decrease will be significantly reduced. General phosphorus thermal stabilizers such as phosphoric acid and phosphorous acid act to reduce the activity of titanium, but the thermal stabilizer of the formula (1) is a stabilizer that can express special effects in this cocatalyst system and does not inhibit titanium activity at all. It serves to give stability.

The polyethylene naphthalate chip thus produced is fiberized according to a conventional method.

As described above, the present invention uses the co-catalyst of antimony and titanium in the polyethylene naphthalate melt polymerization step and adds the thermostable compound of Structural Formula (1). Based on the radioactivity, the present inventors have found that physical properties can be improved by optimizing the spinning draft ratio and the stretching temperature, thereby completing the present invention. In particular, the deep cord formed from the high strength polyethylene naphthalate fiber of the present invention has excellent dimensional stability and strength, and can be usefully used as a reinforcement material for rubber products such as tires and belts or for other industrial uses.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are not intended to limit the present invention, but are not limited thereto. Various physical property evaluations of the yarns manufactured in Examples and Comparative Examples of the present invention were performed by the following method.

(1) Intrinsic viscosity (I.V.)

After dissolving 0.1 g of the sample in a reagent (90 ° C.) mixed with phenol and 1,1,2,3-tetrachloroethanol at a weight ratio of 6: 4 for 90 minutes to give a concentration of 0.4g / 100ml, Ubbelohde Transfer to a viscometer was carried out for 30 minutes in a 30 degreeC thermostat, and the drop number of seconds of the solution was calculated | required using a viscometer and an aspirator. The falling seconds of the solvent was also determined in the same manner, and then the R.V.value and the I.V.value were calculated by the following equations (1) and (2).

Where C represents the concentration of the sample in solution (g / 100ml).

(2) strength

Using Instron 5565 (manufactured by Instron, USA), 250 mm sample length, 300 mm / min tensile speed and 80 turns / s under standard conditions (20 ° C., 65% relative humidity) according to ASTM D 885 Elongation was measured under conditions of m.

(3) Color b

Hunter Lab values were measured using Garder's Color-view Spectrophotometer 9000.

Example 1

In the transesterification reaction, 0.2 mol% of transesterification catalyst Mn based on the number of moles of naphthalene 2 and 6-dicarboxylate was used, the reaction temperature was carried out at 190 to 240 ° C, and the naphthalene 2, 6-dicar during polycondensation. Regarding the number of moles of carboxylate, a thermal stabilizer using 60 ppm Sb as a polymerization catalyst and 20 ppm titanium catalyst as a polymerization catalyst, wherein R ₂ and ₃ are tertiary butyl and R ₄ and ₅ are ethyl in the substituents of the formula (1). 300 ppm was added and polymerization was carried out at a reaction temperature of 240 to 290 ° C. The prepared polymer was subjected to solid phase polymerization to prepare a solid phase polymerized polyethylene naphthalate chip having an intrinsic viscosity (IV) of 1.0 and a moisture content of 20 ppm. The prepared chips were melt spun using an extruder at a discharge rate of 515 g / min and a spinning draft ratio of 40 at a temperature of 310 ° C. This undrawn yarn was wound at a spinning speed of 470 m / min, given 2% free throw, and stretched in two stages. The first stage stretching was carried out 6.0 times at 158 ℃, the second stage stretching was performed 1.1 times at 163 ℃, heat-fixed at 230 ℃, relaxed 1% and then wound to prepare a final stretched yarn (yarn) of 1500 denier.

Physical properties of the melt melt temperature at 310 ℃ using an extruder are shown in Table 1 below.

[Example 2 and Comparative Examples 1 to 6]

A stretched yarn was prepared by performing experiments in the same manner as in Example 1 while changing the content of the catalyst and the kind of heat stabilizer as shown in Table 1. The physical properties thus prepared were evaluated and shown in Table 1 below.

Remarks Catalyst (ppm) Heat stabilizer Raw chip Yarn Change in Extruder IV (dl / g) Color b Reaction time (min) Tenacity (g / den) IV change (dl / g) Example 1 Sb: 60 Ti: 30 Formula (1) 300 ppm 0.55 3.3 165 9.9 0.17 Example 2 Sb: 40 Ti: 26 Formula (1) 300 ppm 0.55 3.1 170 9.9 0.16 Comparative Example 1 Sb: 240 Formula (1) 300 ppm 0.55 3.1 181 9.6 0.15 Comparative Example 2 Ti: 40 Formula (1) 300 ppm 0.55 6.7 168 9.5 0.21 Comparative Example 3 Sb: 180 Ti: 10 Formula (1) 300 ppm 0.55 3.1 175 9.6 0.16 Comparative Example 4 Sb: 20 Ti: 37 Formula (1) 300 ppm 0.55 6.5 180 9.6 0.19 Comparative Example 5 Sb: 40 Ti: 26 No input 0.55 5.5 178 9.4 0.19 Comparative Example 6 Sb: 40 Ti: 26 TMP 0.55 5.4 220 9.4 0.20

* IV: intrinsic viscosity

As shown in Table 1, the heat stabilizer of Equation 1 above was used properly, and the strength of the fiber using the cocatalyst was the best, and excellent results were obtained in all sectors such as viscosity reduction, color, and reaction time. When the type and content of the catalyst are not within the scope of the present invention under the same conditions (Comparative Example 1-4), or when the thermal stabilizer is not used (Comparative Example 5) or when the thermal stabilizer is used as the trimethyl phosphate (Comparative Example 6), etc. It was found that thirteen compared with the example.

In the present invention, a new cocatalyst system composed of an antimony catalyst, a titanium catalyst, and a thermal stabilizer of Structural Formula (1) is used in a polyethylene naphthalate melt polymerization step to simultaneously use an antimony catalyst and a titanium catalyst to complement the disadvantages, thereby causing synergy. The heat stabilizer supplemented the thermal stability of the titanium catalyst to produce polyethylene naphthalate fiber with improved thermal stability, dimensional stability, high strength, and high strength, and the deep cord formed from the reinforcement of rubber products It is usefully used as.

Claims (3)

(A) The content of the antimony catalyst in the polymerization step of polyethylene-2,6-naphthalate containing 85 mol% or more of ethylene-2,6-naphthalate units is 40 to 150 ppm based on the antimony metal, The content is 5 to 50 ppm based on titanium metal, and the heat stabilizer content of the following structural formula (1) is melted in the range of 0.4 to 0.75 dl / g using a cocatalyst system having 5 to 50 ppm based on the content of phosphorus. Polymerizing; (B) solid phase polymerization at an intrinsic viscosity in the range of 0.70 to 1.20 dl / g; (C) winding the solidified unstretched yarn by passing the molten yarn produced by melt spinning the solid-state polymerized chip through a delay cooling and cooling zone; (D) a method for producing polyethylene naphthalate fiber, comprising the step of stretching the wound yarn in multiple stages. Structural Formula (1)

(R ₁ : -OH, R _{2 ~} R ₅ : C _n H _{2n + 1} wherein n = 0 to 5, R _{1 ~} R ₃ is a substituent of Ph.)       In the polymerization step of polyethylene-2,6-naphthalate containing 85 mol% or more of ethylene-2,6-naphthalate units, the antimony catalyst is 40 to 150 ppm based on the antimony metal, and the titanium catalyst is titanium It is 5 to 50 ppm based on the metal, the thermal stabilizer content of the following structural formula (1) using a co-catalyst system of 5 to 50ppm based on the content of phosphorus, characterized in that the melt viscosity in the range of 0.4 to 0.75 dl / g The manufacturing method of the polyethylene naphthalate polymer made into. Polyethylene-2,6-naphthalate fiber prepared by the method of claim 1.