KR100577095B1 - High tenacity polyethylene naphthalate fibers obtained by high-speed spinning and process for preparing them - Google Patents

Abstract

The present invention relates to a high-strength polyethylene naphthalate fiber and a method for manufacturing the same, and more particularly, the step of spinning and quenching a polyethylene naphthalate polymer having an intrinsic viscosity of 0.60 to 0.80 dl / g at a spinning speed of 2000 to 4000 m / mim ( First step); Preheating the quenched unburned yarn at a surface temperature of 110 ° C. to 160 ° C. of the first-stage high speed roller (second step); And polyethylene naphthalate fibers obtained by the manufacturing method comprising a multistage hot drawing at a total draw ratio of 1.3 to 2.5 times (third step) without being damaged when wound on a single-stage high-speed roller, and being uniform in the hot drawing area. It is very useful for rubber reinforcing materials such as tire cords through stretching, weaving, weaving, and uniform strength.

Polyethylene naphthalate fiber, surface temperature, preheating, hot drawing, operability

Description

High Tenacity Polyethylene Naphthalate Fibers Obtained by High-Speed Spinning and Process for Preparing them}

1 is a schematic diagram showing a method for producing polyethylene naphthalate fiber according to the present invention.

The present invention relates to a high strength polyethylene naphthalate (hereinafter abbreviated as "PEN") fiber and a method for producing the same.

The molecular structure of PEN shows a lot of difference in mechanical, thermal, and chemical properties because of its good aromaticity and planarity compared to polyethylene terephthalate (hereinafter, abbreviated as "PET"). PEN has a structure of having a naphthalene ring in the molecular chain and consists of a rigid molecular chain, which has an excellent shape stability when used as an industrial fiber.

However, due to the rigidity of the molecular chain, it is difficult to manufacture high-strength yarns due to the high melting point and glass transition temperature of the polymer, and in particular, due to the high melting temperature of the spinneret, high molecular weight decreases and radioactive deterioration occurs due to the generation of polymer carbide. Operation is remarkably inferior by cutting off among the gods.

Prior arts that solve all of these problems have not been proposed, but Korean Patent Application Publication No. 194-0702476, Korean Patent Application Publication No. 2001-0060491, Korean Patent Application Publication No. 2003-0007819 and the like propose a method of manufacturing PEN fibers. .

Republic of Korea Patent Publication No. 1994-0702476 extrudes a molten polyester polymer having a Tg of 100 ℃ or more, intrinsic viscosity of 0.6 or more to 400 ~ 4500m / min undrawn draw speed passing through delayed cooling section and quenching and solidification section of 150 ℃ or more A birefringence ratio of 0.030 to 0.3, a thermal stretching to at least 1.5 / 1 or more, and a minimum strength of 6.5 g / d, a shrinkage of 4% or less, and a modulus of at least 280 g / d were proposed. .

In addition, the Republic of Korea Patent Publication No. 2001-0060491 is installed in the heating sphere directly below the spinneret to prevent the precipitation of carbide around the hole when melt spinning, so that the spinning operation is excellent, and the spinning speed is 100 ~ 1000m / min The non-drawn yarn melt-spun was applied by stretching 50 to 95% of the total drawing ratio in one stage drawing, and 5 to 50% in the two stage drawing, and heat-setting in the fourth and fifth drawing rollers. A method for producing PEN fibers has been proposed.

In addition, Korean Patent Publication No. 2003-0007819 discloses delayed cooling by melt spinning a polyethylene-2,6-naphthalate polymer having a naphthalene dicarboxylate unit of 90 mol% or more and having an intrinsic viscosity of 0.80 to 1.5 through a spinneret. After passing through the zone and the rapid cooling zone, heating to a temperature of 120 ° C. or less and winding on a roller having a spinning speed of 1000 m / min or less, a method of producing a stretched yarn after multistage stretching to a draw ratio of 5.0 or more was proposed.

 In general, in the production of industrial polyester stretched yarn having high strength and form stability, a heating device, a quenching and a solidification section, and heat setting after drawing are well known techniques, and the above patents consider the rigid molecular chain characteristics of PEN. In order to manufacture high-strength PEN fiber, a drawing technology was proposed. However, the unstretched yarn directly under the spinneret of the molten spinning part is quenched and hard, so if the proper surface temperature of the single-stage high roller is not set, it is damaged when wound on the single-stage high roller before stretching and uniformly stretched in the hot stretching area. This is not possible, the thread is generated during hot stretching or heat setting occurs a problem that cannot be manufactured yarn.

Since PEN polymer has a high glass transition temperature, the roller temperature of the weaving process is a very important technology. The method of producing polyethylene naphthalate fiber having good strength and elongation and good operability by setting an appropriate roller surface temperature during and before stretching is performed. Need development

Therefore, the inventors of the present invention, in order to produce a high-strength PEN fiber, the surface temperature of the single-stage high-pressure roller before hot stretching should be set in consideration of the 120 ~ 150 ℃ that the glass transition of the polyethylene naphthalate polymer appears to not be damaged by quenched undrawn yarn It is connected to the thermal stretching roller, so that uniform thermal stretching is possible, and the production rate of the high-speed spinning low magnification (extension ratio 2.5 or less) with the unstretched winding speed of 2000 to 4000 m / min is 1.5 times higher than that of the low-speed spinning high magnification drawn yarn. The present invention has been completed, and it has been found that the drawn yarn having a strength of 7.0 g / d or more can be produced.

Accordingly, an object of the present invention is to provide a production method for producing high strength polyethylene naphthalate fiber and polyethylene naphthalate fiber obtained by the production method.

In order to achieve the above object, the present invention

Spinning and quenching the polyethylene naphthalate polymer having an intrinsic viscosity of 0.60 to 0.80 dl / g at a spinning speed of 2000 to 4000 m / mim (first step);

Preheating the quenched unstretched yarn in a first stage roller with a surface temperature of 110 ° C. to 160 ° C. (second step); And

Multi-step thermal stretching at a total draw ratio of 1.3 to 2.5 times (third stage)

It provides a method for producing polyethylene naphthalate fiber comprising a.

In addition, the present invention provides a polyethylene naphthalate fiber produced by the above production method, the strength is 7.0 g / d or more and the elongation at break 9.0% or more.

The polyethylene naphthalate fiber is very useful as a material for rubber reinforcing materials such as tire cords through processes such as weaving, weaving, and heat treatment.

Hereinafter, the present invention will be described in detail.

The present invention is a polyethylene naphthalate polymer having an intrinsic viscosity of 0.60 to 0.80 dl / g as a raw material and stretched at a total draw ratio of 1.3 to 2.5 times under spinning conditions of 2000 to 4000 m / min spinning polyethylene naphthalate fibers (hereinafter referred to as "PEN "Abbreviated". At this time, when the surface temperature of the one-stage roller roller is out of 110 ° C to 160 ° C, weaving is impossible.

The surface temperature of the single-stage high speed roller was changed by 1.3 ~ 2.5 times of total draw ratio at 44 ℃, 80 ℃, and 100 ℃, but the first hot drawing roller trimming, second hot drawing roller trimming, and heat setting roller trimming respectively. Because of this, we couldn't make it, and when we set the surface temperature to 180 ℃, we couldn't make it by fusion trimming.

However, if the pre-heated hard undrawn yarn under the spinneret of the molten spinning part is preheated at a surface temperature of 110 ° C. to 160 ° C. of the single step high speed roller, it is not damaged when wound on the first step high speed roller. Uniform stretching occurs in the hot stretching region, resulting in stable spinning operation and uniform strength.

When the surface temperature of the single-stage high-speed roller is 110 ° C. to 160 ° C., the total draw ratio can be 1.3 to 2.5 times the thermal draw under spinning conditions of spinning speed 2000 to 4000 m / min, and high strength fiber can be manufactured.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

<Examples 1 to 3>

As shown in Table 1, using a polyethylene naphthalate polymer having an intrinsic viscosity of 0.73 dl / g as a raw material, the surface-temperature of a single-coated roller with quenched unstretched yarn after spinning at a spinning speed of 2000 to 4000 m / mim during melt spinning After preheating at &lt; RTI ID = 0.0 &gt; C, 135 C, &lt; / RTI &gt;

<Comparative Examples 1 to 4>

The yarn was manufactured by making the surface temperature of the single-stage high speed roller at 44 times of total draw ratios into 44 degreeC, 80 degreeC, 100 degreeC, and 180 degreeC, respectively. At this time, the primary hot drawing roller trimming, the second hot drawing roller trimming, the heat setting roller trimming, and the first-stage high rolling roller fusion trimming were significantly reduced in operability, thus making yarn impossible. The unstretched yarn under the spinneret of the molten spinning part is quenched and hard, so when wound on a single-stage high-precision roller before being stretched, it is damaged and cannot be uniformly stretched in the heat-stretching zone. There was a problem that cannot be manufactured.

<Comparative Examples 5 to 8>

The yarn was manufactured by making the surface temperature of the 1st stage roller at a draw ratio 1.8 times into 44 degreeC, 80 degreeC, 100 degreeC, and 180 degreeC, respectively. At this time, the primary thermal drawing roller trimming, the secondary thermal drawing roller trimming, the heat setting roller trimming, and the first stage high-speed roller fusion trimming, respectively, significantly reduced the operability, making the yarn impossible.

<Comparative Examples 9 to 12>

The yarn was manufactured by making the surface temperature of the single-stage high speed roller at 44 times of total draw ratios into 44 degreeC, 80 degreeC, 100 degreeC, and 180 degreeC, respectively. At this time, the primary thermal stretching roller trimming, secondary thermal stretching roller trimming, heat-setting roller trimming, single-stage fixed roller fusion trimming, respectively, significantly reduced the operability, making the yarn impossible.

Comparative Example 13

Yarn was prepared using a polyethylene naphthalate polymer having an intrinsic viscosity of 0.56 dl / g as a raw material, and the yarn thus prepared did not meet the strength characteristics required by the present invention.

Comparative Example 14

The yarn was manufactured with a total draw ratio of 3.0 times, and it was impossible to manufacture the yarn due to trimming during the second heat drawing.

Comparative Example 15

Yarn was manufactured at a spinning speed of 4500 m / min, and it was impossible to manufacture yarn by trimming during the first hot drawing.

Comparative Example 16

Yarn was produced at a spinning speed of 1500 m / min, and it was impossible to manufacture the yarn due to trimming during the second hot drawing.

Intrinsic viscosity (dl / g) Single stage high roller temperature (℃) Single-speed high roller speed (m / min) Total draw ratio (times) Strength (g / d) Elongation (%) Operability Example 1 0.73 160 3125 1.6 8.0 13.0 Good Example 2 0.73 135 2778 1.8 8.5 11.5 Good Example 3 0.73 120 2500 2.0 8.8 10.0 Good Comparative Example 1 0.73 44 3125 1.6 - - 3 gr envoy Comparative Example 2 0.73 80 〃 〃 - - 4 gr envoy Comparative Example 3 0.73 100 〃 〃 - - 5 gr envoys Comparative Example 4 0.73 180 〃 〃 - - 1 GR fusion envoy Comparative Example 5 0.73 44 2778 1.8 - - 3 gr envoy Comparative Example 6 0.73 80 〃 〃 - - 4 gr envoy Comparative Example 7 0.73 100 〃 〃 - - 5 gr envoys Comparative Example 8 0.73 180 〃 〃 - - envoy Comparative Example 9 0.73 44 2500 2.0 - - 3 gr envoy Comparative Example 10 0.73 80 〃 〃 - - 4 gr envoy Comparative Example 11 0.73 100 〃 〃 - - 5 gr envoys Comparative Example 12 0.73 180 〃 〃 - - 1 GR fusion envoy Comparative Example 13 0.56 135 2500 2.0 5.6 14.0 Yarn strength degradation Comparative Example 14 0.73 135 1667 3.0 - - 3 gr envoy Comparative Example 15 0.73 135 4500 1.1 4.5 15.0 1 GR envoy Comparative Example 16 0.73 135 1500 3.3 - - 3 gr envoy

Experimental Example 1 Measurement Method

1. Intrinsic viscosity

The intrinsic viscosity measurement of polyethylene naphthalate followed the general rules of the KS standard (KSMISO1628-1, Determination of Viscosity of Dilute Polymer Solutions Using Plastic-Capillary Viscometer) for the general part. However, the following sample pretreatment and solvent system were used so that the solution in which the polymer sample was dissolved in the solvent was a "true" solution without the microgel and the macromolecules related thereto.

That is, after pretreatment of the sample for 10 minutes in an oven (Inert Oven) of 300 ℃ N ₂ , and allowed to stand for 30 minutes at room temperature, a solution of 100ml of phenol / tetrachloroethane (60:40) is added to 0.4g of the sample, It was dissolved by stirring at 130 ° C. for 1 hour. Intrinsic viscosity was measured at 30 ° C using a Ubbelodhe viscometer.

2. Total draw ratio

In the present invention, the total draw ratio means the following.

[Equation 1]

3. Strength and elongation

In the present invention, the tensile properties were measured using an Instron material tester at a tensile rate of 300 mm / min, a sample length of 250 mm, and an atmosphere of 20 ° C. × 65% RH. In addition, the denier of the sample was measured using the denier creel and applied to the strength calculation.

The high-strength polyethylene naphthalate fiber obtained according to the manufacturing method of the present invention does not suffer from damage when wound on a single-stage high-speed roller, and becomes uniformly stretched in the heat-stretching region, so that it exhibits stable weaving operation and uniform strength. It is very useful to use as a material for rubber reinforcement such as tire cord through a process such as heat treatment.

Claims (2)

Spinning and quenching the polyethylene naphthalate polymer having an intrinsic viscosity of 0.60 to 0.80 dl / g at a spinning speed of 2000 to 4000 m / mim (first step); Preheating the quenched unstretched yarn in a first stage roller with a surface temperature of 110 ° C. to 160 ° C. (second step); And A method for producing polyethylene naphthalate fiber, comprising the step (third step) of multi-stage hot stretching at a total draw ratio of 2.5 to 1.3 times. The method for producing polyethylene naphthalate fiber according to claim 1, wherein the polyethylene naphthalate fiber has a strength of at least 7.0 g / d and an elongation at break of at least 9.0%.

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