KR101664933B1 - Process for preparing high modulus polyester multifilament having an excellent dimensional satability - Google Patents

Abstract

The polyester multifilament according to the present invention can be applied to industrial products having properties of high strength, high modulus and low elongation and used as materials of tires, industrial ropes, civil engineering reinforcements, webbing or seat belts. Draft can be maintained at 1200 ~ 1500 at the time of spinning by increasing the hole diameter and spinning speed of the proper spinning nozzle, and it is easy to secure the strength of the yarn even at a low drawing ratio due to the increase of the orientation of the undrawn yarn. The increase of the shrinkage ratio and the decrease of the morphological stability of the yarn can be solved as well as the manifestation of the strength.

Description

Technical Field [0001] The present invention relates to a process for preparing a high modulus polyester multifilament having an excellent dimensional stability,

The polyester multifilament according to the present invention can be applied to industrial products having properties of high strength, high modulus and low elongation and used as materials of tires, industrial ropes, civil engineering reinforcements, webbing or seat belts.

A conventional method useful for increasing the strength of polyester fibers used for industrial purposes is to melt a highly viscous chip having an intrinsic viscosity of 1.0 or more, melt the polymer by raising the temperature of the molten polymer sufficiently to 300 DEG C and solidify it, Or less, and then unwinding the undrawn yarn obtained by direct winding at a draw ratio of 5.0 or more in a first stage and a second stage, followed by relaxation and winding. At this time, low-speed winding lowers the degree of orientation in the unstretched state and gives high-strength stretching to obtain high strength characteristics. The conventional method as described above is characterized in that the temperature of the heating hood and the cooling wind is appropriately adjusted to minimize the degree of orientation of the unstable yarn, followed by stretching at a high magnification. When the stretching magnification is increased to obtain fibers having higher strength by using the conventional spinning technique, the viscosity at the time of spinning, the increase in the shrinkage ratio of the yarn due to high-rate stretching, and the shape stability are lowered due to the high temperature of the heating hood during spinning. A large number of finishing threads and finishing problems occur due to a large number of spinning yarns caused by high-ratio stretching, resulting in poor post-processability. In addition, there is a problem in that the viscosity of the high-viscosity PET resin is lowered during spinning, and the shrinkage ratio of the yarn due to high-degree stretching is increased and the shape stability is lowered. In order to overcome the above problems, the HMLS method also has problems in that the strength is inferior in shape stability when taken in terms of strength and shape stability (shrinkage ratio + Chinese shine), and strength is not obtained when shape stability is good.

The polyester multifilament of the present invention can increase the hole diameter and spinning speed of the nozzle to maintain drafts of 1200 to 1500 at the time of spinning and thereby increase the degree of orientation of the unstretched yarn to thereby easily secure the strength of the yarn even at a low stretching ratio, It is possible to solve the problem that the shrinkage ratio of the yarn and the morphological stability are deteriorated.

According to a preferred embodiment of the present invention, a polyether terephthalate chip having an intrinsic viscosity of 1.0 to 1.2 is melted through an extruder and melted through a nozzle having a hole diameter of 1.0 to 1.4 mm and an odd number of 300 to 500 Wherein the polyethylene terephthalate multifilament is produced by extruding a polymer and stretching it in multiple steps through a godet roller at a draft of 1200 to 1500 to produce polyethylene terephthalate multifilament.

According to another preferred embodiment of the present invention, the length of the hole of the nozzle / the diameter of the hole is 4 or more.

According to another preferred embodiment of the present invention, the strength of the polyethylene terephthalate multifilament is 9.0 g / d or more.

Draft can be maintained at 1200 ~ 1500 at the time of spinning by increasing the hole diameter and spinning speed of the proper spinning nozzle, and it is easy to secure the strength of the yarn even at a low drawing ratio due to the increase of the orientation of the undrawn yarn. The increase of the shrinkage ratio and the decrease of the morphological stability of the yarn can be solved as well as the manifestation of the strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a process for producing a polyethylene terephthalate multifilament according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the configuration and operation of embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The polyethylene terephthalate polymer for the production of polyethylene terephthalate yarns of the present invention may contain at least 85 mol% of ethylene terephthalate units, but may optionally contain only ethylene terephthalate units.

Optionally, the polyethylene terephthalate may comprise a small amount of units derived from ethylene glycol and terephthalenedicarboxylic acid or derivatives thereof and one or more ester-forming components as copolymer units. Examples of other ester forming components that can be copolymerized with the polyethylene terephthalate unit include glycols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and the like, and glycols such as terephthalic acid, isophthalic acid, hexahydroterephthalic acid, Dicarboxylic acids such as dicarboxylic acid, dicarboxylic acid, dicarboxylic acid, dicarboxylic acid, dicarboxylic acid, dicarboxylic acid,

Terephthalic acid (TPA) and ethylene glycol raw material are melt-mixed in a ratio of 2.0 to 2.3 to the polyethylene terephthalate chip thus produced, and the molten mixture is transesterified and condensation-polymerized to form a low chip (intrinsic viscosity: 0.60 to 0.70 level raw chip). Subsequently, the low chip is subjected to solid phase polymerization so as to have an intrinsic viscosity of 1.0 to 1.2 and a water content of 30 ppm or less at a temperature of 240 to 260 DEG C and under vacuum.

If the intrinsic viscosity of the raw chips is lower than 1.0, the intrinsic viscosity of the final stretch yarn is lowered and the high strength can not be exhibited as a treated cord after heat treatment. On the other hand, if the intrinsic viscosity of the chips is higher than 1.20, the radiation tension is excessively increased, A lot of filament cuts are generated during stretching and the drawing workability is poor. In addition, when the moisture content of the chips exceeds 30 ppm, hydrolysis may be induced during melt spinning.

Alternatively, an antimony compound, preferably antimony trioxide, may be added as a polymerization catalyst in the condensation polymerization reaction so that the residual amount of antimony metal in the final polymer is 180 to 300 ppm. When the residual amount is less than 180 ppm, the polymerization reaction rate is slowed and the polymerization efficiency is lowered. When the residual amount is more than 300 ppm, unnecessary antimony metal acts as a foreign substance and the radiation-drawing workability may be deteriorated.

The polyethylene terephthalate chip produced by this method is fiberized through the process shown in Fig.

1, a polyethylene terephthalate chip is fed through an extruder 1, a gear pump 2, a nozzle 3 and a heating device 4 at a spinning temperature of 290 to 310 占 폚 and a spinning draft of 1200 to 1500 (The linear velocity on the first winding roller / the linear velocity on the nozzle) to prevent the degradation of the viscosity of the polymer due to pyrolysis and hydrolysis. If the radiation draft ratio is less than 1200, the uniformity of the filament cross section is deteriorated, and the drawing workability is significantly lowered. On the other hand, if the draft ratio is more than 1500, filament breakage occurs during spinning, and normal yarn production becomes difficult.

It is also preferable that the polyether terephthalate chip having an intrinsic viscosity of 1.0 to 1.2 is extruded through a nozzle having a hole diameter of 1.0 to 1.4 mm and an odd number of 300 to 500. At this time, if the diameter of the nozzle hole is less than 1.0, the drawability of the non-drawn yarn is lowered, and when the diameter of the nozzle hole is more than 1.4 mm, the workability upon winding is lowered. If the number of odd number of nozzles is less than 300, the strength of the cord is lowered. If the number of odd number of nozzles is more than 500, uniform cooling is difficult to be performed. The length of the hole of the nozzle / the diameter of the hole is 4 or more. At this time, if the length of the hole of the nozzle / the diameter of the hole is less than 4, the strength of the drawn yarn is decreased.

The produced melt release yarn passes through the cooling zones 5 and 6 and is quenched and solidified and if necessary the distance to the starting point of the cooling zones 5 and 6 immediately below the nozzle 3, A short heating device 4 may be installed.

The length (L) section of the hood becomes a delayed cooling zone or heating zone and has a length of 50 to 250 mm and a temperature of 250 to 400 ° C (air contact surface temperature).

The open quenching method, the circular closed quenching method and the radial outflow quenching method can be applied according to the method of blowing the cooling air in the cooling zones 5 and 6, But is not limited to. The solidified discharged yarn passing through the cooling zones 5, 6 is oiled to 0.5 to 1.0% by the emulsion applying device 7 and becomes unleaded.

The undrawn yarn is drawn by a series of stretching rollers 8, 9, 10, 11, and 11 at a spinning speed of 2800 to 3200 m / min and a winding speed of 5,500 m / 12 and stretched to a total draw ratio of 2.0 times or more, preferably 2.0 to 2.5 times, to obtain the final drawn yarn 13 on the take-up roller.

In the stretching step, the unstretched yarn is stretched in three stages, and each stretching temperature is lower than 95 占 폚, which is the glass transition temperature of the non-stretched yarn. If the stretching temperature is lower than the glass transition temperature, the stretching property is lowered. If the stretching temperature is higher than 95 占 폚, the crystallization during the stretching rapidly proceeds and the 3-stage stretching becomes difficult.

Making the distance between the nozzle and the top of the cooling zone as small as possible during spinning makes it advantageous to have high strength in the final drawn yarn. If the distance from the bottom of the nozzle to the bottom of the heating device is less than 50 mm (actually, since there is an emission block having a length of about 50 mm directly under the nozzle, the distance from the bottom of the nozzle to the bottom of the heating device, 100 mm), or if the distance between the lower part of the heating device and the upper part of the cooling device deviates from 50 to 150 mm, non-uniformity of the non-drawn yarn is generated to a considerable level,

The physical properties of Examples and Comparative Examples were measured or evaluated as follows.

1) Intrinsic viscosity (I.V.)

0.1 g of the sample was dissolved in a reagent (90 ° C) mixed with phenol and 1,1,2,2-tetrachloroethanol 6: 4 (weight ratio) for 90 minutes, transferred to a Ubbelohde viscometer, For 10 minutes, and use a viscometer and an aspirator to determine the number of drops of the solution. The number of drops of the solvent The RV value and I.V. Values were calculated.

R.V. = Sample falling water / solvent falling water water

I.V. = 1/4 × (R.V.- 1) / concentration + 3/4 × (In R.V./ concentration)

2) How to measure the modulus and strength of multifilament

The yarn is left in a standard temperature condition, that is, in a constant temperature and humidity room at a temperature of 25 ° C and a relative humidity of 65% for 24 hours, and then the sample is measured by a tensile tester by ASTM 2256 method.

3) Dry Heat Shrinkage (%, Shrinkage) and ES Value

On the 25 ℃, 65% RH for 24 hours, allowed to stand, of a length measured in a 0.05g / d static load (L ₀₎ and a 150 ℃ after treatment in static load for 30 minutes. 0.05g / d length (L ₁₎ The dry heat shrinkage ratio was measured using the ratio. The construction shrinkage ratio S can be expressed by the following equation.

S (%) = [(L ₀ - L ₁ ) / L _{0 ]} × 100

The elongation under a constant load is referred to as an intermediate elongation (E) in the present invention, and 'S' means the dry heat shrinkage ratio, and the sum of the elongation modulus (E) and dry heat shrinkage ratio (S) is represented by 'ES'.

ES = elongation at break (%) + dry heat shrinkage (%)

4) Radiation draft

The rate of GR 1 (8) was calculated by dividing by the speed of the polyethylene terephthalate polymer underneath the nozzle.

5) Pulling Ratio

The value of GR 4 (11) divided by the speed of GR 1 (8).

6) Dry Heat Shrinkage Force (N, Shrinkage Force)

The maximum value (F) of the generated stress after treatment for 2 minutes at a constant load (F ') of 0.05 g / d using a Testrite apparatus after being left at 25 ° C. and 65% RH for 24 hours . The dry heat shrinkage force (SF) can be expressed by the following formula.

SF (N) = F '- F.

[Example 1]

A solid state polymerized polyethylene terephthalate chip having an intrinsic viscosity (I.V.) of 1.0, a manganese / phosphorus ratio of 1.8, and a water content of 20 ppm, each containing 40 and 220 ppm of manganese and antimony metals, was prepared. The prepared chips were melt-spun using an extruder at a temperature of 295 DEG C under the spinning condition of Table 1. At this time, a static mixer having three units was installed in the polymer conduit of the pack to uniformly mix the melt-spun polymer. Then, the discharged yarn was solidified by passing through a heating zone (atmosphere temperature: 320 ° C) of 100 mm directly below the nozzle and a cooling zone (blowing of cooling air having a wind velocity of 0.5 m / sec at 20 ° C) of 500 mm in length, Respectively. This POY yarn was wound at the spinning speed shown in Table 1 to prepare a final drawn yarn (yarn) of 1500 denier.

[Examples 2 to 4 and Comparative Example 1]

Experiments were carried out in the same manner as in Example 1 while varying the intrinsic viscosity of the chips, the odd number of the spinneret, the spinning speed and the winding speed as shown in Table 1 below to produce a drawn yarn.

The physical properties of the thus-prepared stretch yarn were evaluated and are shown in Table 1 below.

Normal Item unit Comparative Example 1 Example 1 Example 2 Example 3 Example 4 radiation
Condition Beam (° C) 294 295 292 295 292 Nozzle (mm) 0.8 1.0 1.2 1.0 1.2 inspiration (mmaq) 110 130 130 130 130 exhaust (mmag) 120 140 140 140 140 Coiling
speed GR 1 (m / min) 2500 2950 2950 3000 3000 GR 4 (m / min) 5500 5800 5800 5800 5800 DRt - 2.20 1.97 1.97 1.93 1.93 Exterior - - △ - × ○ ~ △ ○ ~ △ ○ ~ △ ○ ~ △ Yarn Denier - 1540 1540 1543 1542 1543 strong Kg 13.5 14.2 14.1 13.7 13.6 burglar g / d 8.8 9.2 9.1 9.1 9.0 Chinese % 5.9 5.8 5.8 5.8 5.8 Omission % 12.7 12.5 12.4 12.5 12.8

*: Excellent appearance,: Fair appearance, X: Bad appearance

Although the present invention has been described with reference to the above embodiments, the present invention is not limited thereto. It will be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

1: Extrude 2: Gear Pump
3: Nozzle 4: Heating device
5 to 6: cooling zone 7: emulsion application device
8 to 12: stretching roller 13:

Claims (3)

A polyether terephthalate chip having an intrinsic viscosity of 1.0 to 1.2 is melted through an extruder and melted through a nozzle having a hole diameter of 1.0 to 1.4 mm, an odd number of 300 to 500, and a hole length / hole diameter of 4 or more A method for producing a polyethylene terephthalate multifilament wherein a polymer is extruded and a spinning draft is drawn at a speed of 1200 to 1500 through a godet roller to multi-stage stretching to produce polyethylene terephthalate. delete The method according to claim 1,
Wherein the strength of the poly (ethylene terephthalate) multifilament is 9.0 g / d or more.

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