KR100595991B1 - Polyethylene-2,6-naphthalate fibers - Google Patents

Abstract

The present invention relates to a polyethylene naphthalate fiber that improves the strength of the drawn yarn by adjusting the fineness and force-strain curve of the undrawn yarn, and melt-extruded polyethylene-2,6-naphthalate chips having an intrinsic viscosity of 0.80 to 1.2 through spinnerets. After passing through a suitable heating section under the spinneret, it is then cooled and solidified using a cooling gas, and has a force strain curve of less than 8% when the unstretched yarn is subjected to an initial stress of 0.2 g / d at room temperature. The high-strength polyethylene-2,6-naphthalate yarn produced by the method comprising the steps of winding the yarn at a radial speed of 0.001 to 0.015, and multistage stretching the wound yarn to a total draw ratio of 4.0 or more. It is about.

In addition, the deep cord prepared from the high strength polyethylene-2,6-naphthalate industrial company of the present invention exhibits excellent strength utilization and adhesion.

Polyethylene-2,6-naphthalate, High strength, Cedenier, Strong utilization, Adhesion

Description

Polyethylene-2,6-naphthalate fibers             

1 is a process schematic diagram illustrating a fiber spinning process of the present invention

Figure 2 is a force-strain curve of the non-drawn yarn of the present invention

The present invention relates to a polyethylene naphthalate fiber that improves the strength of the drawn yarn by adjusting the fineness and force-strain curve of the undrawn yarn, the industrial yarn produced by the present invention provides a treated cord (excellent utilization and adhesion) do.

Polyethylene-2,6-naphthalate has a bulky naphthalate unit, which has a higher glass transition temperature, crystallization temperature, melting temperature, and melt viscosity than polyethylene terephthalate. That is, in order to lower the melt viscosity of the melt during spinning has been spun at a relatively higher temperature than the normal spinning temperature (290 ~ 310 ℃).

However, spinning at high temperatures can lead to pyrolysis of the melt, resulting in poor stretchability and a significant decrease in intrinsic viscosity, which can lead to high strength yarns using polyethylene-2,6-naphthalate polymers. I) was difficult to manufacture (see Japanese Patent Laid-Open Nos. 47-35318, 48-64222 and 50-16739).

Thus, Japanese Patent No. 2945130 manufactures high strength and high modulus polyethylene-2,6-naphthalate fibers by adjusting the spinning speed and spinning draft ratio instead of increasing the spinning temperature and adjusting the stretching temperature step by step. How to do it. According to this method, however, not only uniform spinning is difficult, but also a much higher temperature than the general drawing temperature is required during the first stage drawing, and in this case, there is a problem that normal drawing is difficult due to the widening of the drawing.

At high intrinsic viscosity (IV), preferably in the low spin rate range of 200 to 1000 m / min at intrinsic viscosity (IV) 0.8 to 1.2, the degree of fineness and orientation between undrawn filaments It is generally well known in the field of manufacturing industrial polyethylene-2,6-naphthalate that the uniformity of the polymer is further improved to enable high magnification of the yarn to increase the strength of the yarn.

Considering this theoretically, when manufacturing industrial polyester yarns, the strength of the final stretched yarn can be increased only by increasing the radial tension to increase the orientation of the non-drawn yarn and the formation of a tie chain connecting the crystals with the crystals. In order to obtain a higher strength stretched yarn, it is necessary to obtain an undrawn yarn microstructure capable of high magnification stretching.                         

In this regard, the present invention was able to increase the strength of the final drawn yarn by adjusting the fineness of the undrawn yarn and the force-strain curve, thereby increasing the orientation of the undrawn yarn and the formation of a tie chain connecting crystals and crystals.

The present invention relates to a high-strength polyethylene naphthalate fiber in which fineness and force-strain curves of undrawn yarn are adjusted, and a force-strain curve that stretches less than 8% when subjected to an initial stress of 0.2 g / d is obtained. High-strength polyethylene having excellent physical properties by maximizing the formation of a tie chain that connects the crystals with the orientation and crystals of the unstretched yarn in the stretching step by winding the yarn at a birefringence such that the birefringence is 0.001 to 0.015. Its purpose is to provide 2,6-naphthalate fibers and methods for their preparation.

It is also an object of the present invention to provide a high strength polyethylene naphthalate fiber with improved physical properties, which is useful for the production of tire cords with good strength utilization and adhesion.

The present invention (A) extruded a polymer containing not less than 85 mol% of ethylene naphthalate units and having an intrinsic viscosity in the range of 0.80 to 1.2 at a temperature of 290 to 330 ° C., and then quenching the melt-release yarn through a delayed cooling zone. Solidifying, (B) the undrawn yarn has a single yarn fineness of 13 to 30 denier, has a force strain curve that is less than 8% when subjected to an initial stress of 0.2 g / d at room temperature, and has a birefringence of 0.001 to 0.015 It provides a polyethylene naphthalate fiber having the following physical properties, produced by the method comprising the step of winding the yarn at a spinning speed to be (C) multistage stretching the wound yarn at a total draw ratio of 4.0 times or more.

(1) intrinsic viscosity of 0.6 to 1.0, (2) strength of 9.0 g / d or more, (3) elongation of 6% or more, (4) 2 to 4 denier of single yarn fineness, (5) 1000 to 2000 denier of total fineness, (6) shrinkage of 1 to 4%

It is also preferable that the total fineness of the stretched yarn is 1500 denier and the number of filaments is 500.

It is also preferable that the total fineness of the stretched yarn is 1500 denier and the number of filaments is 385.

Further, in step (A), it is preferable to install a heating zone adjacent to just before the cooling zone and having an ambient temperature of 300 to 400 ° C. and a length of 200 to 700 mm.

In addition, the spinning speed in the step (B) is preferably 200 to 1000 m / min.

The present invention provides a deep cord obtained by treating two strands of polyethylene naphthalate fibers up and down and treating with resorcinol-formalin-latex (RFL).

In addition, it is preferable that the strong utilization rate of the deep code is 85%.

In addition, it is preferable that the adhesive strength of the deep cord is 10kg or more.

The present invention provides a rubber product in which a deep cord is incorporated as a reinforcing material.                     

The polyethylene-2,6-naphthalate polymer used in the present invention contains at least 85 mole% 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 a small amount 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, stilbene Dicarboxylic acids such as dicarboxylic acid, bibenzoic acid, adipic acid, sebacic acid, azelaic acid.

Polyethylene naphthalate chip according to the present invention, preferably naphthalene-2,6-dimethylcarboxylate (NDC) or naphthalene-2,6-dimethylcarboxylic acid (NDA) and ethylene glycol raw material in a ratio of 1.4 to 3.0 Melt mixing at 170-220 ° C., and the melt mixture was subjected to transesterification (for about 1 to 5 hours at 180 to 250 ° C.) and condensation polymerization (for about 1 to 5 hours at 260 to 300 ° C.). After making a raw chip of 0.42 to 0.70 level, it is solid-phase polymerized to have an intrinsic viscosity of 0.80 to 1.20 and a moisture content of 50 ppm or less under a temperature of 240 to 260 ° C and a vacuum.

The present invention may optionally add a manganese compound, preferably manganese acetate, in a transesterification reaction in an amount such that the remaining amount of manganese metal in the final polymer is in the range of 30 to 70 ppm, the amount being 30 If it is less than ppm, the transesterification reaction rate becomes too slow, and if it is more than 70 ppm, more manganese metals than necessary will act as foreign matters, causing problems during solid state polymerization and spinning.

In the present invention, optionally, during the polycondensation reaction, as a polymerization catalyst, an antimony compound, preferably antimony trioxide, may be added in an amount such that the amount remaining as antimony metal in the final polymer is from 100 to 400 ppm. If less, the polymerization reaction rate is lowered, and the polymerization efficiency is lowered. If it is more than 400 ppm, the antimony metal more than necessary acts as a foreign material, which reduces the radio-stretching workability. At this time, a phosphorus heat resistant stabilizer, preferably trimethyl phosphate, may be added in an amount such that the remaining amount of phosphorus element in the final polymer as 10 to 80 ppm, the manganese / phosphorus content ratio is 2.0 or less. When the manganese / phosphorus content ratio is higher than 2.0, the oxidation is promoted during the solid phase polymerization, so that normal physical properties cannot be obtained during spinning.

The polyethylene naphthalate chip thus produced is fiberized according to the method of the present invention, and FIG. 1 schematically shows a manufacturing process according to one embodiment of this invention.

In step (A), the polyethylene naphthalate chip is passed through the pack 1 and the nozzle 2 at a spinning temperature of preferably 290 to 328 ° C., preferably of a spinning draft ratio of 20 to 200 (on the first take-up roller). Low-temperature melt spinning at a linear velocity / linear velocity) can prevent a decrease in the viscosity of the polymer due to thermal decomposition and hydrolysis. If the spinning draft ratio is less than 20, the uniformity of the filament cross section is poor, the drawing workability is significantly decreased. If the spinning draft ratio is more than 200, the filament breakage occurs during spinning, making it difficult to produce normal yarn.

In addition, in this invention, it is an important factor to adjust the filtration residence time in a pack to 3-30 second. If the filtration residence time in the pack is less than 3 seconds, the filtration effect of the foreign matter is insufficient, and if it is more than 30 seconds, the molecular weight decreases due to excessive pack pressure increase.

In addition, in the present invention, it is preferable to set the L / D (length / diameter) of the extruder screw to 15 to 50, which is difficult to uniformly melt when the L / D of the screw is less than 15, and to exceed 50 due to excessive shear stress. Molecular weight fall is severe and physical property is inferior.

In step (A), the quenching yarn 4 is quenched by passing through the cooling zone 3, if necessary, the distance from the nozzle 2 directly under the nozzle 2 to the starting point of the cooling zone 3, ie the length of the hood ( L) A short heating device may be fitted in the section.

This zone is called a delayed cooling zone or heating zone, which has a length of 200 to 700 mm and a temperature of 300 to 400 ° C. (air contact surface temperature).

In the cooling zone 3, an open quenching method, a circular closed quenching method, and a radial outflow quenching method may be applied depending on a method of blowing cooling air. It is not limited to. Subsequently, the discharged yarn 4 solidified while passing through the cooling zone 3 can be oiled by the emulsion applying device 5 to 0.3 to 1.2%.

In step (B), the undrawn yarn has a single yarn fineness of 13 to 30 denier, has a force strain curve that is less than 8% when subjected to an initial stress of 0.2 g / d at room temperature, and the birefringence is 0.001 to 0.015. The yarn is wound at a spinning speed to be preferred, and the preferred spinning speed is 200 to 1,000 m / min.

In the present invention, the fineness of the undrawn yarn, the force-strain curve, and the birefringence are used as factors for controlling the microstructure of the undrawn yarn.

As a key technical matter in the present invention, the fine yarn fine yarn of undrawn is 13 to 30 denier to be finely adjusted than the conventional one. In the prior art, the single yarn fineness of the undrawn yarn mainly exceeds 30 denier. In this case, the undrawn yarn has too fine fineness, so that uniform cooling is difficult. That is, due to the cooling difference between the surface and the inside of the unstretched yarn causes damage to the yarn in the stretching process. Further, if the single yarn fineness of the undrawn yarn is 13 denier or less, the number of filaments of the undrawn yarn is increased, resulting in poor radioactivity.

The present invention is characterized in that the undrawn yarn has a force deformation curve that is less than 8% when subjected to an initial stress of 0.2 g / d at room temperature.

Unstretched yarn having the force deformation curve can be maximized in the stretching process in the subsequent stretching process.

In addition, in the present invention, the birefringence of the undrawn yarn is used as a factor for controlling the microstructure of the undrawn phase together with the force-strain curve.

In particular, in the present invention, as described above, the excellent stretchability can be obtained in the stretching process only if the unstretched force deformation curve and the birefringence satisfy the above-described ranges. For this reason, if the birefringence of the undrawn yarn is less than 0.001, the crystallization rate is too slow in the drawing step to sufficiently induce the formation of tie chains between the crystals. If the birefringence exceeds 0.015, the crystallization progresses too rapidly during drawing. Rather, it is difficult to manufacture high strength yarns due to poor elongation.

In step (D), the yarn having passed through the first stretching roller 6 is passed through a series of stretching rollers 7, 7, 8, 9 and 10 by spin draw, while the total draw ratio is at least 4.0 times, preferably The final stretched yarn 11 is obtained by stretching to 4.5 to 6.5.

While narrowing the distance between the nozzle and the top of the cooling section as possible during spinning, it is advantageous to have high strength in the final stretch yarn, but during spinning, the distance from the nozzle to the bottom of the heating device is less than 50 mm (actually the length directly under the nozzle Since there is a radiation block of about 50mm, the distance from the bottom of the heater to the bottom of the heater becomes 100mm when using a heater of 50mm in length. A large amount of nonuniformity is generated, and it is impossible to draw a normal physical property.

Stretched polyethylene naphthalate fibers produced according to the method of the present invention have (1) intrinsic viscosity of 0.6 to 1.0, (2) strength of 9.0 g / d or more, (3) elongation of 6% or more, and (4) single yarn fineness of 2 to 4 denier, (5) total fineness, 1000-2000 denier, (6) 1-4% shrinkage.

In addition, the drawn yarn produced according to the present invention can be converted into a treatment code by a conventional treatment method.

For example, a cord yarn is prepared by plying & cabling two strands of 1,500 denier drawn yarns at 300 to 450 tpm (twist / m) (the number of twists based on a general polyethylene-2,6-naphthalate treated cord). First immersed in the adhesive liquid RFL (Resorcynol- Formalin- Latex) in the first dipping tank, and then under a stretch of 1.0-4.0% at 130-160 ° C in the drying zone. Dry for 150 to 200 seconds, heat set for 45 to 80 seconds with a stretch of 2.0 to 6.0% at a temperature of 230 to 250 ° C in a hot stretching zone, and then the second dipping tank (2nd Dipping Tank) was again immersed in the adhesive liquid (RFL) and dried for 90 to 120 seconds at a temperature of 130 to 160 ℃, then 45 to a temperature of 230 to 250 ℃ and -4.0 to 2.0% stretch (Stretch) Heat set for 80 seconds (Heat Set) to prepare a dipped cord (dipped cord).

The deep cord thus prepared (based on 1,500 denier 2-strand top and bottom 390tpm) has a strong utilization of 80% or more and an adhesive strength of 10 kg or more.

As such, the treatment cord made of high modulus and low shrinkage polyethylene-2,6-naphthalate multifilament yarn according to the present invention has excellent dimensional stability and strength, and thus is used as a reinforcement material for rubber products such as tires and industrial belts or other industrial purposes. It can be usefully used for the purpose.

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 and treatment cords prepared 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 number of 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 equation.

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 20 turns / s under standard conditions (20 ° C., 65% relative humidity) according to ASTM D 885 Elongation was measured under conditions of m.

(3) shrinkage

The sample was left at 20 ° C. and 65% relative humidity for at least 24 hours, and then weighed at a weight corresponding to 0.1 g / d to measure the length (L 0), and at 150 ° C. for 30 minutes using a dry oven under no tension. After the treatment was taken out and left for 4 hours or more, the load (L) was measured, and the shrinkage ratio was calculated by the following equation.

(4) Intermediate Shinto

On the elongation SS curve, the yarn was elongated at 4.5 g / d and the treated cord was elongated at 2.25 g / d, thereby making it an intermediate elongation.

(5) birefringence

Measurement is made using a polarizing microscope equipped with a Berek compensator.

      (6) adhesion

H-test was performed to measure the initial adhesion of the treated deep cord to the rubber. H-test ensures that both ends of the deep cord are embedded in a 9.5mm rubber block, and the gap between the rubber blocks at both ends is kept at 9mm and the rubber is pulled on both sides to measure the maximum load at which the rubber-cord separation occurs. How to evaluate. In addition, by vulcanizing at a temperature of 160 ° C. and 25 kg / cm ² for 20 minutes before the evaluation of adhesive force, the rubber is given sufficient strength and measured. The rubber composition used in the test was 100 parts of natural rubber, 3 parts of zinc oxide, 28.9 parts of carbon black, 2 parts of stearic acid, 7.0 parts of pintar, 1.25 parts of MBTS, 3 parts of sulfur, 0.15 parts of diphenyl guanidine and phenylbeta naphthylamine 1.0 part is mix | blended.

(7) strong utilization rate

Strong utilization of the deep code is measured by the following equation.

Strong Utilization (%) = Deep Code Strong / {[Existency Strong] × 2} × 100

Example 1

A solid-state polymerized polyethylene naphthalate chip having an intrinsic viscosity (I.V.) of 0.91 containing 42 and 200 ppm of manganese and antimony metals, respectively, was prepared. The produced chip was melt spun using an extruder at a discharge rate of 515 g / min and a spinning draft ratio of 41 at a temperature of 312 ° C. The screw of the extruder used at this time was adjusted to L / D of 25, and a static mixer having five units was installed in the polymer conduit of the pack to evenly mix the melt-spun polymer. Subsequently, the discharged yarn is solidified through a 40 cm long heating zone (atmosphere temperature 350 ° C.) and a 500 mm long cooling zone (20 ° C., cooling air blowing with a wind speed of 0.5 m / sec), followed by oiling with a spinning emulsion. It was. The undrawn yarn was wound at a spinning speed of 470 m / min, gave 2% free draw, and stretched in two stages. The first stage stretching was 6.0 times at 148 ° C., the second stage stretching was 1.1 times at 193 ° C., the heat setting at 230 ° C., 2% relaxation, and then winding to prepare a final drawn yarn (yarn) of 1500d / 500f.                     

After two strands of yarn were rolled up and down at 390 turns / m to prepare cord yarns, the cord yarns were immersed in the adhesive solution of (PCP resin + RFL) in a dipping tank and then stretched 1.0% to 170 ° C in a dry area. After being dried for 150 seconds and heat-fixed at 240 ° C. for 150 seconds in a high temperature stretching area, it was again immersed in RFL, dried at 170 ° C. for 100 seconds, and heat-set at 240 ° C. under -1% stretching for 40 seconds to prepare a treatment cord.

The physical properties of the drawn yarn and the treated cord thus prepared are shown in Table 2 below.

[Examples 2 to 5 and Comparative Examples 1 to 4]

The stretched yarn and the treatment cord were prepared by performing experiments in the same manner as in Example 1 while changing the single yarn fineness of the undrawn yarn as shown in Table 1 below.

The physical properties of the drawn yarn and the treated cord thus prepared are shown in Table 2 below.

TABLE 1

division Spinning temperature (℃) Chip Intrinsic Viscosity Cooling zone Heating zone Unpainted Shrine Wind speed (m / sec) Temperature (℃) Length (cm) Temperature (℃) Birefringence Single Sand Island (Denier) Elongation at 0.2g / d Initial Load (%) Thread 1 312 0.91 0.5 20 40 350 0.009 19.5 5.0 Thread 2 312 0.91 0.5 20 40 350 0.007 26.0 7.2 Thread 3 312 0.91 0.5 20 40 350 0.011 13.0 4.6 Rain 1 312 0.91 0.5 20 40 350 0.006 39.0 8.2 B2 312 0.91 0.5 20 40 350 0.005 52.0 9.7 Rain 3 312 0.91 0.5 20 40 350 0.023 6.5 3.9

TABLE 2

division Drawing company Processing code Remarks Intrinsic viscosity Birefringence Strength (g / d) Elongation (%) Fine island (denier) Single Sand Island (Denier) Shrinkage (%) Strong (kg) Intermediate Elongation (%) Shrinkage (%) Strong utilization (%) Adhesion (kg) Thread 1 0.78 0.452 9.7 9.5 1500 3 1.9 24.7 2.3 2.0 85 14.3 Thread 2 0.77 0.453 9.6 9.8 1500 4 2.2 23.6 2.2 2.2 82 13.2 Thread 3 0.77 0.454 9.7 9.1 1500 2 2.2 24.4 2.2 2.3 84 15.4 Rain 1 0.74 0.444 9.4 9.9 1500 6 2.1 21.9 2.2 2.2 78 9.7 B2 0.77 0.450 8.8 10.1 1500 8 2.2 19.8 2.2 2.2 75 8.6 Rain 3 0.75 0.446 9.8 8.5 1500 One 4.2 22.3 2.2 2.2 76 16.3 ■

■: The appearance is extremely poor and there is no meaning of manufacturing the treatment code.

The present invention provides a high strength polyethylene-2,6-naphthalate fiber having excellent physical properties by maximizing the formation of a tie chain connecting the crystals with the orientation and crystals of the undrawn yarn. And it provides a preparation method thereof. In addition, the industrial company manufactured by the present invention provides a treated cord (excellent utilization and adhesion) excellent.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims. .

Claims (9)

(A) extruding a polymer containing not less than 85 mol% of ethylene naphthalate units and having an intrinsic viscosity in the range of 0.80 to 1.2 at a temperature of 290 to 330 ° C., and passing the molten yarn through a delayed cooling zone and then rapidly quenching , (B) The unstretched yarn has a single yarn fineness of 13 to 30 denier at room temperature and elongates less than 8% when subjected to an initial stress of 0.2 g / d, and has an initial modulus of 10 to 50 g / d and a birefringence of 0.001 to 0.015. Winding the yarn at a rate of (C) Polyethylene naphthalate fibers having the following physical properties, prepared by the method comprising the step of multi-stretching the wound yarn at a total draw ratio of 4.0 times or more. (1) intrinsic viscosity of 0.6 to 1.0, (2) strength of 9.0 g / d or more, (3) elongation of 6% or more, (4) 2 to 4 denier of single yarn fineness, (5) 1000 to 2000 denier of total fineness, (6) shrinkage of 1 to 4% The method of claim 1, Polyethylene naphthalate fiber, characterized in that the spinning speed in the step (B) is 200 to 1000 m / min. The method of claim 1, Polyethylene naphthalate fiber characterized in that the total fineness of the drawn yarn is 1500 denier, the number of filaments is 500. The method of claim 1, Polyethylene naphthalate fiber characterized in that the total fineness of the drawn yarn is 1500 denier, the number of filaments is 385. The method of claim 1, Polyethylene naphthalate fiber produced by the method characterized in that the heating zone of the ambient temperature is 300 to 400 ℃ and the length of 200 to 700mm adjacent to immediately before the cooling zone in step (A). A deep cord obtained by treating two strands of polyethylene naphthalate fibers of claim 1 up and down and treating with resorcinol-formalin-latex (RFL). The method of claim 6, Deep code, characterized in that the strong utilization rate of the deep code is more than 80%. The method of claim 6, The deep cord, characterized in that the adhesive strength of the deep cord is 10kg or more. A rubber product in which the treatment cord of claims 6 to 8 is incorporated as a reinforcing material.

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