KR20070016469A - Method for preparing polyester multifilament yarn for reinforcement of rubber and polyester multifilament yarn prepared by the same method - Google Patents

Abstract

The present invention comprises the steps of: a) polymerizing a terephthalic acid (TPA) and ethylene glycol (EG) by adding a polymerization catalyst containing 150 to 250 ppm of antimony compound based on antimony metal; b) solid-phase polymerization of the polymer obtained in step a); c) melt spinning the solid polymer obtained in step b); d) winding the melt-spun filament at a speed of at least 1500 m / min to obtain an undrawn yarn having a density of at least 1.338 g / cm ³ ; And e) the unstretched yarn obtained in step d), intrinsic viscosity: 0.83 or more, strength: 8.3 g / d or more, carboxyl terminal groups of 20 micro equivalents / g or less, and diethylene glycol of 1.2 wt% or less It provides a method for producing a rubber reinforcing polyester multifilament yarn comprising the step of producing a yarn and the polyester multifilament yarn produced thereby. The polyester multifilament yarn according to the present invention can be usefully used in the manufacture of treatment codes such as tire cords as rubber reinforcements.

Rubber reinforcements, polyester multifilament yarns, polymerization catalysts, antimony compounds

Description

Manufacture method of polyester multifilament yarn for rubber reinforcement and polyester multifilament yarn produced by this method

The present invention relates to a method for producing polyester multifilament yarns and to polyester multifilament yarns produced by the method. More specifically, the present invention relates to a process for producing industrial polyester multifilament yarns having high modulus and low shrinkage, useful as rubber reinforcements, and polyester multifilament yarns produced by the process.

General manufacturing method of industrial high modulus and low shrinkage polyester multifilament yarn is based on high-speed spinning of 1,500m / min or more, based on the method of drawing at 1.5 ~ 2.5 magnification in multiple stages and heat setting at high temperature. I am doing it. However, the yarn prepared by this method is not finer microstructure than the yarn produced by spinning at a low speed of 1500m / min or less, and has a chemical weakness such as hydrolysis, pyrolysis.

Accordingly, US Pat. No. 4,751,143 describes limiting the carboxyl end group (CEG) level of yarn to 18 micro equivalents / g or less. In addition, Japanese Patent No. 2822503 describes diethylene glycol (DEG) yarn level of 1.3 wt% or less and carboxyl terminal group (CEG) level of 25 micro equivalents / g or less.

Meanwhile, in order to improve production workability of industrial high-speed spinning yarns and properties as final rubber reinforcement materials, various techniques such as draw ratio distribution, drawing temperature control, heat setting temperature control, spinning emulsion selection, steam jet in the yarn manufacturing process Techniques such as stretching using a technique may be used. However, even if the above-described technique is used, if the polyester polymer is basically excellent in heat resistance and is not favorable for strong expression, it is a rubber reinforcing material such as tire cord, which has a desired level of high modulus, low shrinkage rate and high tenacity. You don't get the properties of.

As an example of the polymerization catalyst used to manufacture the polyester fiber for rubber reinforcement so far, Japanese Unexamined Patent Publication No. 37-5821 describes an example of using manganese acetate, antimony trioxide, and a phosphate catalyst system. Japanese Patent Application Laid-Open No. 55-12781 describes an example using calcium acetate, antimony trioxide and phosphorous acid. Japanese Patent Application Laid-Open No. 51-134789 discloses an example using lithium acetate, antimony trioxide, and phosphorous acid. However, the manufacturing technology of the rubber reinforcement polyester fiber using this catalyst is a catalyst technology prior to the development of high strength industrial polyester multifilament yarn manufacturing technology with high modulus and low shrinkage rate using high-speed spinning, 1,500m / min In the case of using the high-speed spinning technique described above, it is inappropriate to use a large amount of foreign substances due to the aggregation of the polymerization catalyst.

Japanese Patent No. 2822503 finds that metal antimony produced by reduction of an antimony compound used as a polymerization catalyst has a great bad effect on strength and toughness. An example of using at -150 ppm is described. However, in this case, it is described that a thin film polymerization method is used to shorten the polymerization time by increasing the melt surface area to volume during the polymerization, or at 130 ppm or less of antimony metal, it is described to obtain a commercial polymerization effect only when used in combination with another polymerization catalyst.

U.S. Patent No. 4,867,936 describes the use of 300 to 400 ppm and 0.5 to 1.5 ppm titanium compounds as antipolymer as a polymerization catalyst for the production of high strength industrial polyester multifilament yarns with high modulus and low shrinkage. In the production of polyester multifilament yarns for reinforcement industry, antimony compound is used as a polymerization catalyst at 250 to 350 ppm as an antimony metal. However, when 250 to 350 ppm of antimony compound is used as a polymerization catalyst, the antimony metal separated in the polymerization process adheres to the melt spinning pack filter, which increases the pressure applied to the pack, thereby shortening the pack replacement cycle. However, the adverse effect of poor elongation will appear.

On the other hand, U.S. Patent No. 5,997,789 discloses a replacement cycle of the pack by coating the filter with SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , SiC, TiN, TiCN, TiC, etc. to prevent the antimony metal from adhering to the filter. It suggests how to extend it. In addition, an example in which ₂₀₀ to 400 ppm of TiO ₂ is added to a polyethylene terephthalate polymer is used. The metal added in the polymer is a cause of inhibiting physical expression as a tire cord, such as strength and heat resistance.

The inventors of the present invention studied a method for producing a polyester multifilament yarn having high modulus and a low shrinkage property for use as a rubber reinforcing material as a polymerization catalyst for polymerization using terephthalic acid (TPA) as a raw material and subsequent solid phase polymerization. Even when the antimony compound is used at 150 to 250 ppm based on the antimony metal, it has been found that the solid phase polymerization rate may not be lowered compared to the prior art using 250 to 350 ppm based on the antimony metal. In addition, when the antimony compound is used at 150 to 250 ppm based on the antimony metal as the polymerization catalyst, the spinning processability and the stretchability of the polymer are improved as compared to the conventional method, and the yarn production efficiency is increased, and the manufactured polyester multifilament yarn is treated. It has been found that it is useful as a rubber reinforcement with excellent modulus (strong utilization rate) and heat resistance, and high modulus, low shrinkage and high strength characteristics when manufactured by cord.

Accordingly, an object of the present invention is to provide a method for producing a polyester multifilament yarn useful as a rubber reinforcing material and a polyester multifilament yarn produced by the method.

The present invention

a) polymerizing a terephthalic acid (TPA) and ethylene glycol (EG) by adding a polymerization catalyst containing 150 to 250 ppm of an antimony compound based on antimony metal;

b) solid-phase polymerization of the polymer obtained in step a);

c) melt spinning the solid polymer obtained in step b);

d) winding the melt-spun filament at a speed of at least 1500 m / min to obtain an undrawn yarn having a density of at least 1.338 g / cm ³ ; And

e) drawing the unstretched yarn obtained in step d) above, intrinsic viscosity: 0.83 or more, strength: 8.3 g / d or more, carboxyl end groups of 20 micro equivalents / g or less, and diethylene glycol of 1.2 wt% or less Manufacturing steps

It provides a method for producing a polyester multifilament yarn comprising a.

In addition, the present invention is a polyester multifilament yarn produced by the above method, the intrinsic viscosity of 0.83 or more, carboxyl end group (CEG) 20 micro equivalents / g or less, diethylene glycol content 1.1 wt% or less, yarn strength It provides a polyester multifilament yarn having a 8.3 g / d or more.

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

When an antimony compound is used as a polymerization catalyst in the production of polyester multifilament yarns, a small amount of antimony metal is reduced during the polymerization process. In addition, the reduced antimony metal has been known to cause problems such as deteriorating the spinning process conditions such as blocking the pack filter or reducing the elongation, adversely affecting the physical properties of the treated cord using the manufactured yarn. Therefore, in the prior art, attempts to use very small amounts of antimony compounds as polymerization catalysts have been made as described above. In this case, a separate polymerization catalyst or a special polymerization method such as a thin film polymerization method should be used. There was. In particular, in order to manufacture industrial yarns, such as rubber reinforcement materials, which require high intrinsic viscosity, in addition to melt polymerization using terephthalic acid (TPA), unlike in the manufacturing method of garments, additional solid phase polymerization is required. Many polymerization catalysts have been known to be required.

However, in the present invention, it has been found that by controlling the polymerization conditions in the preparation of the polyester multifilament yarn, even if an antimony compound is used at 150 to 250 ppm based on the antimony metal, the solid phase polymerization rate may not be reduced. By using the antimony compound in an amount in the above range, the reduced antimony metal content in the polymer can be 5 ppm or less, thereby improving the spinning processability and the stretchability, and the polyester multifilament yarn manufactured It is possible to have a lath, a low shrinkage rate and a high strength, and to greatly improve the strong expression rate and the heat resistance when manufacturing the treated cord.

Hereinafter, each step of the manufacturing method of the polyester multifilament yarn according to the present invention will be described in detail.

In the method for producing polyester multifilament yarn according to the present invention, step a) is a step of polymerizing by adding an antimony compound to terephthalic acid (TPA) and ethylene glycol (EG) at 150-250 ppm based on antimony metal. The antimony compound in step a) is preferably used as a polymerization catalyst 150 to 250 ppm, preferably 150 to 220 ppm as the antimony metal. When the antimony compound is used in excess of 250 ppm of antimony metal, the filter of the spin pack is blocked by precipitation of reduced metal antimony, which significantly shortens the pack use cycle, decreases stretchability, reduces workability, and rubbers the manufactured yarn. In order to use for reinforcing materials, immersion in the adhesive (RFL) and the heat treatment process goes through a strong utilization rate drops. In addition, when the antimony compound is used at less than 150 ppm of the antimony metal, the polymerization rate cannot be controlled only by controlling the polymerization temperature and the degree of vacuum, and the polymerization rate is significantly slowed, making commercial production difficult.

In the step a), as the polymerization catalyst, a catalyst other than an antimony compound may be used in combination, and other catalysts include, for example, a Ti-based compound and an Al-based compound. In this case, however, it is preferable that the antimony compound is 80 wt% or more in the total polymerization catalyst added. In addition, in step a), a metal compound such as titanium dioxide or silica other than the polymerization catalyst may be added for spinning, stretching workability improvement, or other purposes. However, even in this case, the metal compound is preferably added within a range that does not significantly adversely affect the heat resistance and the strong expression of the yarn prepared according to the present invention, for example, may be added to 150 ppm or less.

The molar ratio of ethylene glycol / terephthalic acid in step a) is preferably 1.1 to 1.2. In the present invention, by using the molar ratio of ethylene glycol / terephthalic acid in the above range, the unreacted terephthalic acid may be present in the polymer prepared in step a) below 50 ppm. If the unreacted terephthalic acid in the polymer exceeds 50 ppm, the yarn is poorly prepared, which makes difficulty in producing a high strength yarn.

In the step a), the polymerization temperature is not particularly limited, but is preferably 275 to 288 ° C. In addition, it is preferable to adjust the polymerization temperature and time to increase the esterification reaction rate by 98% or more. If the esterification reaction rate is not more than 98%, a large amount of unreacted terephthalic acid is present, and the yarn manufacturing processability is remarkably degraded, which is disadvantageous for high strength yarn production.

In the latter stage of the polymerization in the step a), the polymerization can be efficiently carried out with a relatively small amount of polymerization catalyst by allowing the polymer to remain at least 1.5 hours, preferably at least 2 hours, under a high vacuum of 2.5 torr or less in the final polymerization reactor. have. In the final polymerization reactor, if the vacuum takes more than 2.5 torr or the residence time is less than 1.5 hours, the reduced metal antimony and unreacted terephthalic acid are not sufficiently removed, and the remaining amount of metal antimony is over 5 ppm, and the unreacted terephthalic acid is released. It has a result exceeding 50ppm, which is disadvantageous in the production of high strength yarns and the strength expression and heat resistance as a rubber reinforcement material.

The polymer obtained by the polymerization of step a) performed under the above conditions is a polyethyleneglycol terephthalate polymer having 95% or more of ethylene glycol terephthalate repeating units, among which the reduced metal antimony is 5 ppm or less, and unreacted terephthalic acid It is 50 ppm or less, and intrinsic viscosity (IV) is 0.6-0.8 level.

According to the method of the present invention, the polymer obtained in step a) is subjected to solid phase polymerization in step b). The solid phase polymerization method may use a method known in the art, and is not limited to a specific method. For example, the solid phase polymerization may be carried out between 180 ° C. and the melting temperature, preferably at a temperature of 220-240 ° C. under vacuum or under a nitrogen atmosphere. The solid phase polymer obtained by the solid phase polymerization is obtained at an intrinsic viscosity of at least 0.9 level, preferably at a level of 1 to 1.15, in order to make the yarn produced thereby have a high strength of 8.3 g / d or more required by an industrial yarn.

According to the method of the present invention, the solid polymer obtained in step b) is melt spun in step c). The melt spinning method may use a method known in the art, and is not limited to a specific method. In the present invention, the melt spinning is preferably spinning the solid polymer by using an extruder while preventing the thermal decomposition of the polymer by setting the moisture content in the solid polymer to 25 ppm or less and the temperature of the radiation beam at a temperature as low as 300 ° C. or less. It can be carried out by extrusion molten spinning through the mold. At this time, the spinning can be carried out with the spinning speed of 1,500m / min or more, and other spinning conditions as appropriate. The undrawn yarn obtained in this step has an intrinsic viscosity (I.V.) of at least 0.83 and a density of at least 1.338 g / cm 3.

In the present invention, the unstretched yarn obtained after the extrusion melt spinning step of c) may be solidified by passing a delay cooling zone and a rapid cooling zone by cooling air directly below the spinneret. The delay cooling zone can be both heated and non-heated.

In the present invention, after the extrusion melt spinning in step c) is stretched in step d) to give a spinning oil impregnated with a spinning oil at a speed of 1500m / min or more to prepare a polyester yarn. The stretching of step d) may be performed, for example, by stretching the undrawn yarn at a draw ratio of 1.5 to 2.5 levels. After this stretching step, it is preferable to heat-set the stretched yarn to a high temperature to stabilize it.

The drawn yarn obtained as described above has an intrinsic viscosity (IV) of 0.83 or more, preferably 0.88 or more, a carboxyl end group (CEG) of 20 micro equivalents / g or less, preferably 18 micro equivalents / g or less, and diethylene The glycol (DEG) is 1.2 wt% or less, preferably 1.1 wt% or less, and yarn strength is 8.3 g / d or more, preferably 8.5 g / d or more. The yarns produced according to the present invention exhibit relatively high strength utilization (strength of tire cords / strength of yarns) and heat resistance when used as rubber reinforcement materials such as tire cords, in particular, compared to conventional yarns of at least 8.3 g / d yarn strength. . Polyester multifilament yarn having such physical properties is useful for rubber reinforcement. In addition, when the density of the yarn is 1.38 to 1.3865 g / cm 3, heat treatment in the post process shows better strength expression (strength utilization) when the process cord is manufactured.

The diethylene glycol (DEG) level, carboxyl end group (CEG) level, intrinsic viscosity level of the yarn has a direct effect on the strength of the yarn, tire cord strong expression (strong utilization), heat resistance. For example, when the diethylene glycol level exceeds 1.2% by weight or the carboxyl end group (CEG) of the yarn exceeds 20 micro equivalents / g, the strong expression (strength utilization) and heat resistance of the rubber reinforcement material, which is the final product, are inferior. Appears. When the ethylene glycol / terephthalic acid molar ratio is out of the range of 1.1 to 1.2, the diethylene glycol (DEG) level and the carboxyl terminal group (CEG) level are outside the above-mentioned standards, and the yarn strength, treatment code strong expression (strong utilization rate), It is disadvantageous in heat resistance.

The trimming ratio of the polyester multifilament yarn produced by the method of the present invention is 0.8 times / ton, and the equivalent strength prepared by using the existing polymerization catalyst antimony compound at 250 to 350 ppm based on antimony metal, such as 8.5 g / d Compared with 3.0 times / ton of yarn trimming rate, the yarn is significantly improved. In addition, the strength utilization at the maximum draw ratio (Max. DRt.) Is remarkably improved by more than 2% compared to yarns using polymers having the same intrinsic viscosity.

The polyester multifilament yarn according to the present invention can be converted into a treatment cord by a conventional treatment method. For example, two strands of drawn yarn of 1000 denier are plyed & cabling at 440 turns / m (typical twist of a polyester processed cord) to prepare a cord yarn, and then a rubber adhesive liquid (RFL liquid) After immersion, the treatment cord is prepared by stretching 2.0 to 5.0% and heat setting for 1.5 to 2.5 minutes at a temperature of 230 to 245 ° C. Compared to the existing high modulus low shrink yarns having the same yarn strength, the treated cords (1000 denier two strand upper and lower lead 440 turns / m basis) are more powerful when subjected to heat treatment during post-processing such as rubber adhesive treatment as rubber reinforcing materials. The utilization rate is improved by 2% or more, resulting in a processing code having high modulus and low shrinkage characteristics with improved heat resistance.

Treatment cords made of polyester multifilament yarns produced by the method according to the invention have dimensional stability (E _2.25 + FS), where E _2.25 is elongation at _2.25 g / d and FS is free shrinkage It has this value of 5.5 to 8.0%, and intensity | strength is 6.8 g / d or more, Preferably it is 6.9-8.5 g / d.

In short, according to the present invention, the pack pressure increase due to the metal accumulated in the spinning filter in the high-modulus and low-shrinkage yarn manufacturing process is improved, so that the filter cycle is extended by 50% or more, and the maximum draw ratio is 10% compared with the conventional polymer. It is higher than this, and the strength of the yarn at the maximum draw ratio is improved by 5% or more, thereby improving physical properties and productivity. It is also possible to produce high strength, high modulus and low shrinkage yarns with excellent utilization in treated cords.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are for illustrating the present invention, and the scope of the present invention is not limited by the examples.

Evaluation of various physical properties of the yarn and the treated cord manufactured in Examples and Comparative Examples of the present invention was carried out by the following method.

(1) viscosity

In accordance with ASTM D 4603, 0.1 g of the sample was dissolved in a reagent (90 ° C.) mixed with phenol and 1,1,2,2-tetrachloroethane at a weight ratio of 6: 4 for 90 minutes to give a concentration of 0.4g / 100ml, followed by Ube It transferred to the Ubbelohde viscometer, hold | maintained for 10 minutes in the 30 degreeC thermostat, and calculated | required the falling number of seconds of the solution using the viscometer and the aspirator.

The number of falling seconds of the solvent was also determined in the same manner, and then R.V. (relative viscosity) values and I.V. (intrinsic viscosity) values were calculated by the following equations (1) and (2).

<Equation 1>

R.V. = Number of drops of sample / number of drops of solvent

<Equation 2>

I.V. = 1/4 × [(R.V.-1) / C] + 3/4 × (lnR.V./C)

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

(2) carboxyl terminal group (CEG) level analysis

Samples were dissolved using benzyl alcohol and analyzed using acid base neutralization titration. Specifically, samples of about 0.2 g were taken and 10 ml of benzyl alcohol was added thereto. After dissolving by heating in a 200 ° C. heating block for 10 minutes, the mixture was cooled in a water bath for 1 minute. 10 ml of chloroform and an indicator of phenol red, phenolphthalein or bromothymol blue were added thereto, and titrated with 0.1 N KOH (or NaOH).

(3) Diethylene Glycol (DEG) Level Analysis

It was analyzed by GC after aminoamine decomposition using monoethanol amine. Specifically, 1 g of a PET sample was taken, 3 ml of monoethanol amine was added thereto, a cooler was mounted therein, and then completely decomposed on a hot plate. After cooling, 20 ml of MeOH and 10 g of terephthalic acid (TPA) containing an internal standard (1,6-hexanediol) were added, followed by analysis using GC. DEG standard quantification curves were prepared using MeOH solutions containing the same internal standards and having DEG contents of 0, 0.05, 0.1, and 0.15%, respectively.

(4) Analysis of unreacted terephthalic acid (TPA) content

TPA was quantified by HPLC after selective dissolution using reprecipitation method. Specifically, samples of about 0.1 g were taken, and 1 ml of HFIP (Hexafluoro iso-propanol) was added thereto to completely dissolve it. 5 ml of MeOH was added to selectively reprecipitate the polymer and the solution was filtered and analyzed by HPLC. TPA standard quantitative curves were prepared using 1% ammonia water and prepared by HPLC analysis under the same conditions as the sample solution.

(5) reduced metal antimony content

The polymer was dissolved in 500 ml of orthochlorophenol, centrifuged (12,000 rpm x 2 hrs), washed and dried. The spectrum of the obtained centrifugal precipitated particles was measured by an X-ray diffractometer to quantify metal antimony from spector.

(6) strength, elongation

Using Instron 5565 (Instron, USA), measurements were taken under standard conditions (20 ° C., 65% relative humidity) at a sample length of 250 mm, tensile rate of 300 mm / min and 80 turns / m in accordance with ASTM D 885.

(7) density

Density is measured in a xylene / carbon tetrachloride density gradient at 23 ° C. Density gradient tubes are made according to ASTM D 1505 with a density in the range of 1.33-1.41 g / cm 3.

(8) shrinkage

The sample was left at 20 ° C. and 65% relative humidity for at least 24 hours, and then weighed at 0.1 g / denier to measure the length (L ₀ ). Subsequently, in a tension-free state, a dry oven was used for 30 minutes at 150 ° C., and then left for 4 hours or more to measure the length (L) by applying a load to calculate a shrinkage ratio using Equation 3 below.

<Equation 3>

ΔS (%) = (L ₀ -L) / L ₀ × 100

(9) Intermediate Shinto

The elongation SS curve measures the elongation at a load equivalent to 4.5 g / d for yarns (1000 denier basis) and the elongation at a load of 2.25 g / d for treatment cords (1000 denier two-strand top and bottom twisted yarns). It was.

(10) Dimensional stability (E _2.25 + FS)

The dimensional stability of the treatment cord is defined as the high modulus at a given shrinkage as a property related to side wall indentation (SWI) and handling. E _2.25 (elongation at _2.25 g / d) + FS (free shrinkage) is useful as a measure of dimensional stability for treated cords treated with different heat treatments, the lower the better the dimensional stability.

(11) strong utilization rate

It is calculated by Equation 4 using the intensity value measured in the above (6).

<Equation 4>

Strong utilization (%) = (strength of treated cord / strength of yarn) × 100

(12) heat resistance in rubber

The treated cord was placed in a rubber compound for adhesion test provided by Hankook Tire and vulcanized at 150 ° C. × 6hrs to evaluate the strong retention. When the strong retention rate is 70% or more,? Is indicated by 60 to 70%, and × by 60% or less.

Example 1

Ethylene glycol and terephthalic acid were melted in a molar ratio of 1.15: 1, and antimony trioxide was added to 190 ppm of antimony metal (based on the weight of ethylene glycol and terephthalic acid charged) and polymerized at a polymerization temperature of 280-288 ° C. In the latter part of the polymerization, the mixture was kept under vacuum at 1.3 torr for 2 hours in a final polymerization reactor. By this polymerization, the amount of reduced antimony metal was 3 ppm, unreacted terephthalic acid residual amount was 35 ppm, diethylene glycol (DEG) was 0.85 wt%, carboxyl end group (CEG) was 24 micro equivalents / g, intrinsic viscosity (IV) A polyester polymer having a value of 0.65 was obtained.

Subsequently, the polymer was subjected to solid phase polymerization at 237 ° C. for 8 hours to prepare a solid phase polymerized polyethylene terephthalate chip having an intrinsic viscosity (I.V.) of 1.05.

The prepared solid-state polymerized chip is supplied to the extruder under a nitrogen atmosphere with a moisture content of 20 ppm or less, and the single yarn fineness of the final stretched yarn is 4.0 denier using an extruder, with a spinning temperature of 288 ° C. and a discharge amount of 580 g / min, and a 16 micron nonwoven fabric. Using a spinning pack using two filters (manufactured by Natsuron, Japan), melt spinning was performed through a spinning nozzle.

The discharged yarn was then solidified through the heating zone and cooling zone (blown air with a wind speed of 0.5m / sec) just below the nozzle, and then a waterborne spinning emulsion of 15% concentration of the stock solution was added to give a spinning speed of 2200m / min. It was wound up to prepare an undrawn yarn. Subsequently, the unstretched yarn was subjected to three-stage stretching by passing through Godet Rollers, heat-set at 210 ° C. in the heat-fixing roller GR ₄ , and relaxed 2.0%, followed by winding. In this way, the final stretched yarn (yarn) of 1000 denier which is 15 micro equivalent / g of carboxyl terminal group (CEG) was produced.

After producing two cords of yarn by cabling & plying at 440 turns / m, two baths (2 dippings) using Pexul solution in one bath and RFL (Resorcinol-Formalin-Latex) solution in two baths. ) Was stretched to 2.0 to 2.5%, heat set at a temperature of 240 ° C. for 2 minutes, and RFL adhesion was adjusted to 4% to prepare a treatment cord.

The physical properties of the undrawn yarn, the drawn yarn and the treated cord thus prepared are shown in Tables 1 and 2 below.

Comparative Example 1

A solid-phase polymerized polyethylene terephthalate chip was prepared in the same manner as in Example 1 except that 120 ppm of antimony trioxide was added. In Example 1, the solid phase polymerization time was 8 hours, while in Comparative Example 1, 16 hours, which is a considerable time in the solid phase polymerization, was unsuitable for commercial production.

Example 2

Undrawn yarn, drawn yarn and treatment cord were prepared and evaluated for physical properties in the same manner as in Example 1 except that 50 ppm of titanium dioxide was added to the polymer during the initial polymerization. The evaluation results are shown in Tables 1 and 2 below.

Undrawn Yarn and Drawing Process Improvement division  Undrawn Density Total draw ratio Trimming rate (times / ton) Pack Exchange Cycle (Days) Example 1 1.340 2.26 0.8 6 Example 2 1.340 2.26 0.8 6  Total draw ratio: drawing roller maximum linear speed / spinning speed Pack change interval (days) = 100kgG / ㎠ pressure rise period compared to the initial pack pressure

Properties of Drawing Yarns and Treatment Cords  division Drawing company Processing code Intrinsic Viscosity (I.V.) Density (g / cm 3) CEG (μ equivalent / g) Strength (g / d) Majority (%) Elongation (%) Strength (g / d) Majority (%) Elongation (%) Shrinkage (%) Dimensional stability E _2.25 + FS (%) Strong utilization rate (%) Heat resistance Example 1 0.940 1.383 15 8.5 5.6 11.8 7.6 4.5 15.0 2.4 6.8 89.4 ◎ Example 2 0.940 1.384 15 8.5 5.6 11.6 7.5 4.5 14.5 2.4 6.8 88.2 ◎

Examples 3 to 5 and Comparative Examples 2 to 5

Except for the conditions shown in Table 3, the yarn was prepared in the same manner as in Example 1, and physical properties were evaluated. Physical property evaluation results are shown in Tables 4 and 5.

division  Finisher condition EG / TPA ratio Antimony Content (ppm) Pressure Hours (hr) Example 3 1.3 2 1.20: 1 190 Example 4 1.3 2 1.20: 1 150 Example 5 1.3 2 1.20: 1 250 Comparative Example 2 1.3 2 1.25: 1 157 Comparative Example 3 1.3 0.5 1.15: 1 157 Comparative Example 4 1.3 2 1.15: 1 335 Comparative Example 5 3 2 1.25: 1 335

Properties of Polyethylene Terephthalate Polymer (raw chip) division  Antimony Metal Content (ppm) DEG level (wt%) CEG level (μ equivalent / g) (excluding unreacted TPA) Residual Metal Antimony Residuals (ppm) Unreacted TPA Example 3 190 1.1 25 3 35 Example 4 150 1.1 23 2 35 Example 5 250 1.1 25 5 40 Comparative Example 2 157 1.3 25 3 35 Comparative Example 3 157 0.85 32 3 40 Comparative Example 4 335 0.85 25 10 35 Comparative Example 5 335 1.1 32 10 70

Properties of Drawing Yarns and Treatment Cords division Drawing company Processing code Intrinsic Viscosity (I.V.) Density (g / cm 3) CEG (μ equivalent / g) Strength (g / d) Majority (%) Elongation (%) Strength (g / d) Majority (%) Elongation (%) Shrinkage (%) Dimensional Stability E _{2 .25} + FS (%) Strong utilization rate (%) Heat resistance Example 3 0.937 1.385 16 8.5 5.6 12.0 7.6 4.5 15.5 2.5 7.0 89.4 ◎ Example 4 0.939 1.385 16 8.5 5.6 13.0 7.7 4.5 16.0 2.4 6.9 90.5 ◎ Example 5 0.936 1.385 17 8.5 5.6 13.0 7.5 4.5 15.0 2.7 7.2 88.2 Comparative Example 2 0.932 1.383 16 8.3 5.8 13.5 7.1 4.5 15.0 3.7 8.2 85.5 × Comparative Example 3 0.930 1.385 23 8.3 5.5 11.5 7.0 4.5 13.5 2.6 7.1 84.3 × Comparative Example 4 0.936 1.389 16 8.4 5.6 12.0 7.1 4.5 14.5 2.7 7.2 84.5 × Comparative Example 5 0.932 1.383 17 8.3 5.8 13.0 7.1 4.5 14.7 3.6 8.1 85.5 ×

According to the manufacturing method of the polyester multifilament yarn according to the method of the present invention, the yarn processability and elongation is improved, the yarn manufacturing efficiency is greatly improved, as well as the produced polyester multifilament yarn is modulus, shrinkage, strength, strength utilization High strength industrial polyester multifilament yarn for rubber reinforcement having high modulus and low shrinkage due to its excellent heat resistance and the like, and can be usefully used for manufacturing cords such as tire cords.

Claims (12)

a) polymerizing a terephthalic acid (TPA) and ethylene glycol (EG) by adding a polymerization catalyst containing 150 to 250 ppm of an antimony compound based on antimony metal; b) solid-phase polymerization of the polymer obtained in step a); c) melt spinning the solid polymer obtained in step b); d) winding the melt-spun filament at a speed of at least 1500 m / min to obtain an undrawn yarn having a density of at least 1.338 g / cm ³ ; And e) drawing the unstretched yarn obtained in step d) above, intrinsic viscosity: 0.83 or more, strength: 8.3 g / d or more, carboxyl end groups of 20 micro equivalents / g or less, and diethylene glycol of 1.2 wt% or less Manufacturing steps Rubber reinforcing polyester multifilament yarn production method comprising a. The method of claim 1, wherein the antimony compound in step a) is 80 wt% or more of the polymerization catalyst used in step a). The method of claim 1, wherein the molar ratio EG / TPA of terephthalic acid (TPA) and ethylene glycol (EG) in step a) is 1.1 to 1.2. The method according to claim 1, wherein a metal compound is further added as a catalyst other than the polymerization catalyst in step a), and the amount of the metal compound added is 150 ppm or less. The method according to claim 1, wherein in step a), the polymerization temperature is 275 to 288 ° C and the esterification reaction rate is 98% or more. The method according to claim 1, wherein the polymer is held in the second half of the polymerization in the step a) at 2.5 torr or less for 1.5 hours or more. The rubber of claim 1, wherein the polymer obtained in step a) comprises at least 95% of polyethylene glycol terephthalate repeating units, containing 50 ppm or less of unreacted terephthalic acid and 5 ppm or less of reduced antimony metal. Method for manufacturing polyester multifilament yarn for reinforcement. The method according to claim 1, wherein the solid polymer obtained in step b) has an intrinsic viscosity of 0.9 or more. The method according to claim 1, wherein the unstretched yarn prepared in step d) has an intrinsic viscosity of 0.83 or more. 10. Intrinsic viscosity of 0.83 or more, yarn strength of 8.3 g / d or more, carboxyl end group (CEG) 20 micro equivalents / g or less, diethylene glycol produced by the method of any one of claims 1 to 9 Polyester multifilament yarns containing 1.2 wt% or less. Process cord manufactured using the polyester multifilament yarn of claim 10. The processing code of claim 11, wherein the processing code is a tire code.