KR20150079474A - Polyester resin for tire cord and preparation method of the same - Google Patents

Abstract

The present invention relates to a polyester resin for tire cord and a preparation method thereof. According to the present invention, a polyester resin for tire cord having a linear uniform inner structure and improving shape stability and thermal resistance can be manufactured. The polyester resin for tire cord comprises a ester repeated unit in which an aromatic divalent functional group and an aliphatic divalent functional group are connected by a medium of ester combination, and contains antimony (Sb) of 100 to 180 ppmw, and phosphorous (P) of lower than or equal to 30 ppmw, wherein a ratio of average hydrodynamic radius to the weight-average molecular weight is more than or equal to 0.40 nm*mol/g.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyester resin for a tire cord and a method of manufacturing the same. BACKGROUND ART [0002]

The present invention relates to a polyester resin for a tire cord and a method for producing the polyester resin, and more particularly, to a polyester resin for tire cords having a linear uniform internal structure and improved shape stability and heat resistance, and a method for producing the same.

The tire is a composite of fiber / steel / rubber, and generally has a structure as shown in Fig. The body ply corresponds to 6 in Fig. 1, which is a core layer as a core reinforcing material in the tire. The body ply is also called a carcass. It holds the shape of the tire while supporting the overall load of the automobile, It is a part that requires strong fatigue resistance against the bending motion during running. In general, a polyester resin material such as polyethylene terephthalate is applied to such a body ply, that is, a tire cord.

In recent years, the development of tires suitable for high-speed driving has been demanded in accordance with the upgrading of passenger cars. Accordingly, it has been recognized that high-speed driving stability and high durability of tires are very important characteristics. .

Particularly, when a material having a low shape stability is used as a tire cord, if the running speed of the vehicle suddenly increases, the appearance of the tire can be easily deformed to permanently deform the tire. As a result, Or the ride can be reduced.

In general, the shape stability of such a tire cord is influenced by the crystal properties, the crystallization speed, etc., and the crystal characteristics and the crystallization speed are known to be influenced by DEG content, molecular weight, molecular weight distribution, uniformity of molecular structure, have.

More specifically, the higher the crystallization rate of the polyester resin, the higher the morphological stability of the tire cord, and the DEG content, the molecular weight distribution, the molecular weight, the additive, the uniformity of the molecular structure, the degree of branching and the like may affect the crystallization rate.

Accordingly, it is necessary to develop a method for producing a polyester resin for tire cords having a high crystallization rate and excellent shape stability.

An object of the present invention is to provide a polyester resin for tire cords having a linear uniform internal structure and improved shape stability and heat resistance.

The present invention also provides a method for producing a polyester resin for tire cords having a linear uniform internal structure and improved shape stability and heat resistance.

In the present specification, the aromatic divalent functional group and the divalent aliphatic functional group include an ester repeating unit connected via an ester bond, and contain 100 ppmw to 180 ppmw of antimony (Sb) and 30 ppmw or less of phosphorus (P) A ratio of an average hydrodynamic radius to a weight average molecular weight is 0.40 nm * mol / g or more.

Also disclosed herein is a process for producing a polyester prepolymer by reacting a dicarboxylic acid and a glycol in the presence of an antimony based catalyst to form a polyester prepolymer; And a step of solid-phase polymerizing the polyester prepolymer, wherein the antimony-based catalyst comprises 100 ppm to 180 ppmw of antimony relative to the total amount of the dicarboxylic acid and glycol / RTI >

BEST MODE FOR CARRYING OUT THE INVENTION A polyester resin for a tire cord and a method for producing the same according to a specific embodiment of the invention will be described in detail below.

According to one embodiment of the invention, the aromatic divalent functional group and the bivalent aliphatic functional group comprise an ester repeating unit connected via an ester linkage, wherein 100 ppmw to 180 ppmw of antimony (Sb) and 30 ppmw or less of phosphorus (P) , And a ratio of an average hydrodynamic radius to a weight-average molecular weight of 0.40 nm * mol / g or more may be provided.

The present inventors have carried out research on a polyester resin having high shape stability applicable to tire cords and have found that a polyester prepolymer having a high intrinsic viscosity is produced using a small amount of a catalyst and a phosphorus compound, The polyester resin obtained by solid state polymerization in the presence of a small number of branching sites due to side reactions has a high degree of linearization, a uniform internal structure, and excellent shape stability.

The ratio of the hydrodynamic radius to the weight average molecular weight of the polyester resin for tire cord is linearly proportional to the ratio, and may be 0.40 nm * mol / g or more, preferably about 0.45 to 0.68 nm * mol / g.

When the temperature of the polyester resin for tire cords is lowered from 290 ° C to 190 ° C at a rate of 200 ° C / min, the time for which the absolute value of the exothermic peak appears on the DSC may be within about 400 seconds. That is, when the temperature of the polyester resin is reduced from 290 ° C to 190 ° C at a rate of 200 ° C / min and maintained at 190 ° C, when the absolute value of the exothermic peak appears on the DSC from the start of decreasing the temperature at 290 ° C May be less than 400 seconds, which is measured in terms of the crystallization rate in Examples to be described later.

The polyester resin for a tire cord may have a polymer crystallinity of 50% to 60%, preferably 55 to 60%, of the following formula (1).

[Chemical Formula 1]

In the above formula (1), X is the degree of polymer crystallization, ρ _c is the density of the 100% crystalline polymer, ρ _a is the density of the amorphous polymer, and ρ is the density of the ester resin for tire cords.

The polyester resin for a tire cord may have an intrinsic viscosity of 1.0 to 1.4 dl / g. The intrinsic viscosity of the polyester prepolymer may be 0.65 dl / g or more, preferably 0.65 to 0.80 dl / g, and the intrinsic viscosity of the polyester resin prepared by solid phase polymerization may be 1.0 to 1.4 dl / g .

The polyester resin for such a tire cord may be polyethylene terephthalate. That is, the polyester resin is a polyethylene terephthalate resin prepared by using terephthalic acid as a dicarboxylic acid and ethylene glycol as a glycol in accordance with the method for producing a polyester resin for tire cords .

According to another embodiment of the present invention, there is provided a process for producing a polyester prepolymer, which comprises reacting a dicarboxylic acid and a glycol in the presence of an antimony-based catalyst to form a polyester prepolymer; And a step of solid-phase polymerizing the polyester prepolymer, wherein the antimony-based catalyst comprises 100 ppm to 180 ppmw of antimony relative to the total amount of the dicarboxylic acid and glycol Can be provided.

The present inventors proceeded with studies on polyester resins having high shape stability applicable to tire cords, and produced polyester prepolymers having high intrinsic viscosity by using less additives and catalysts that cause side reactions, mild), the polyester resin obtained by solid phase polymerization has a low degree of branching due to side reaction, has a high degree of linearization, a uniform internal structure, and excellent shape stability.

Particularly, in the method for producing a polyester resin for a tire cord in the above embodiment, it is possible to minimize branching caused by internal defects and side reactions which may be caused by using a small amount of an antimony catalyst and a phosphorus compound, A uniform polyester resin can be produced.

The polyester resin for a tire cord is produced by polymerizing a dicarboxylic acid and a glycol in the presence of an antimony-based catalyst containing 100 ppmw to 180 ppmw of antimony based on the total amount of dicarboxylic acid and glycol to prepare a polyester prepolymer ; And solid phase polymerizing the polyester prepolymer.

The step of preparing the polyester prepolymer can suppress the side reaction for producing the branch of the polymer by using a small amount of the additive such as the catalyst which causes the side reaction and thereby the uniformity of the molecular structure of the polymer is improved, The shape stability of the polyester resin can be improved.

The step of preparing such a polyester prepolymer includes esterifying the dicarboxylic acid component and the glycol component; And polycondensing a reaction product of the esterification reaction. The step of polymerizing the dicarboxylic acid and the glycol to prepare a polyester prepolymer may be carried out by melt polymerization Can be seen as a step.

More specifically, the step of esterifying the dicarboxylic acid and the glycol is carried out at a temperature of about 100 to 300 DEG C, preferably about 150 to 260 DEG C for about 1 to 6 hours, preferably about 2 to 5 hours ≪ / RTI >

As the dicarboxylic acid, terephthalic acid, oxalic acid, malonic acid, azelaic acid, fumaric acid, pimelic acid, suberic acid, isophthalic acid, dodecane dicarboxylic acid, naphthalene dicarboxylic acid, biphenyldicarboxylic acid, 1,4-cyclohexane acid, Dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, succinic acid, glutaric acid, adipic acid, Adipic acid, sebacic acid, 2,6-naphthalene dicarboxylic acid, 1,2-norbornane dicarboxylic acid, 1,3 - Cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 1,3 - Cyclobutane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid ( Potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, or a mixture thereof. Preferably, terephthalic acid is used as the dicarboxylic acid .

The glycol may be selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3 Butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,3-propylene glycol, But are not limited to, diethylene glycol, triethylene glycol, cyclohexane diol, 1,3-cyclohexane diol, and cyclohexane diol Propanediol, hexanediol, neopentyl glycol, tetramethylcyclobutanediol, 1,4-cyclohexane diethanol, 1,10-hexanediol, 1,6-hexanediol, Decamethylene glycol, 1,12-dodecanediol, polyoxyethylene glycol, Lee be oxymethylene glycol (Polyoxymethylene glycol), polyoxytetramethylene glycol (Polyoxytetramethylene glycol), glycerol (Glycerol) or may be used and a mixture thereof, preferably may be a glycol.

Next, the reaction product of the esterification reaction of the dicarboxylic acid and the glycol may be polycondensed. The step of polycondensation of the reactants of the esterification reaction can be carried out at a temperature of about 200 to 300 ° C, preferably about 260 to 290 ° C and a reduced pressure of about 0.1 to 1 torr.

The polycondensation reaction of the esterification reaction can be carried out at a temperature of 200 to 300 캜 for 2 to 15 hours, or 4 hours or 10 hours. The polyester prepolymer having higher intrinsic viscosity can be synthesized by reacting the dicarboxylic acid and the glycol for 2 hours or more for 4 hours or more as described above.

The antimony-based catalyst and phosphorus compound can be introduced at any stage of the polyester polymerization. For example, it is possible to feed the reaction mixture only to the esterification reaction step, to the polycondensation step of the esterification reaction, or to both the esterification reaction step and the polycondensation step. Preferably, the antimony- And the phosphorus compound can be added to the polycondensation step.

The intrinsic viscosity of the polyester prepolymer may be 0.65 dl / g or more, and preferably 0.65 to 0.80 dl / g. In the method for producing a polyester resin for a tire cord of the embodiment, the intrinsic viscosity of the polyester prepolymer is made as high as 0.65 dl / g or more and the degree of crystallinity can be kept low, so that the reaction proceeds in the solid phase polymerization step By-products can escape more easily, and the reaction speed becomes faster, so that the solid-state polymerization time can be shortened or the solid-state polymerization temperature can be lowered.

When the temperature of the polyester prepolymer is lowered at a rate of 200 ° C / min from 290 ° C to 210 ° C, the maximum value of the exothermic peak in DSC may be within about 300 seconds. That is, when the temperature of the polyester prepolymer is lowered from 290 ° C to 210 ° C at a rate of 200 ° C / min and maintained at 210 ° C, the absolute value of the exothermic peak appears on the DSC from the start of lowering the temperature at 290 ° C May be less than or equal to 300 seconds, which is measured in terms of the crystallization rate in Examples to be described later.

The polyester prepolymer may have a melt viscosity of 50 Pa · S to 500 Pa · S at a shear rate of 10 S ^{- 1} , and preferably 100 Pa · S to 300 Pa · S.

On the other hand, the antimony-based catalyst used in the method for producing a polyester resin for a tire cord in one embodiment is low in cost and has a high catalytic activity so that the polycondensation rate of the dicarboxylic acid and the glycol can be accelerated, The physical properties such as intrinsic viscosity of the prepolymer can also be improved.

As the antimony-based catalyst, antimony acid antimony, antimony glycolate, antimony triacetate, antimony trioxide (Sb ₂ O ₃ ) or a mixture thereof may be used.

The antimony-based catalyst may include 100 to 180 ppmw of antimony based on the total amount of the dicarboxylic acid and the glycol. The antimony-based catalyst may increase the rate of polycondensation between the dicarboxylic acid and the glycol to promote the production of the polyester prepolymer. However, when an excessive amount of the antimony-based catalyst is used, the deterioration ) Or cause agglomeration under spinneret so as to lower the spinnability at the time of spinning. Therefore, it is preferable to use it in the above-mentioned content range.

In addition, the step of forming the polyester prepolymer may be carried out in the presence of an antimony catalyst, an antimony catalyst and a phosphorus compound. At this time, the phosphorus compound can serve to prevent deterioration and discoloration in the production of the polyester resin. Specifically, the phosphorus compound can prevent deterioration due to heat applied to the esterification exchange reaction and the polycondensation reaction, reaction heat generated as the reaction progresses, and the like, ) Or inhibits the unintended addition reaction by controlling the activity of the catalyst, thereby suppressing the yellowing of the finally formed polyester, thereby making the polyester resin transparent and close to colorless.

The phosphorus compound can form a BHT-P complex or a BHT-Metal-P complex by reacting with bis-2-hydroxyethyl terephthalate (BHT) produced in the esterification process, It can also form a complex with the antimony metal used. Such a composite may remain as a defect in the polyester resin to be finally produced, and the complex may be a cause of lowering the crystallization rate because a polymer is produced in a branched structure.

Therefore, when the phosphorus compound is added in too much amount, it may remain as a defect of the polyester resin or may bind to the catalyst and degrade the activity of the catalyst. Therefore, the phosphorus compound is preferably not more than 30 ppmw based on the total amount of the dicarboxylic acid and glycol, Or 5 ppmw to 30 ppmw of phosphorus, and more preferably 20 ppmw or less. That is, it is preferable to add the phosphorus compound in the above-mentioned range in order to reduce the amount of the phosphorus compound added and prevent the deterioration and discoloration described above.

In the method for producing a polyester resin for a tire cord in one embodiment, polyphosphoric acid, an organic phosphorus compound, a 4-phosphonium compound and the like can be used as the phosphorus (P) -based compound. Specifically, phosphoric acid, trimethylphosphate Known phosphorus compounds such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, phenylphosphine, 2-carboxylethylphenyl phosphinic acid, and mixtures thereof. Compounds may be used.

Next, in the method for producing a polyester resin for a tire cord in one embodiment, the polyester prepolymer produced by the above-mentioned method can be solid-phase polymerized. The solid phase polymerization may be any solid phase polymerization method known to be used in the production of polyester resins such as a batch polymerization method and a continuous solid phase polymerization method.

The solid phase polymerization of the polyester prepolymer may further include pre-crystallizing the polyester prepolymer at a temperature of about 100 ° C to 250 ° C. More specifically, the step of pre-crystallizing the polyester prepolymer can be dried and crystallized for about 1 to 10 hours under an inert gas or vacuum of about 100 ° C to 250 ° C, preferably about 150 to 220 ° C.

In the step of solid-phase polymerizing the polyester prepolymer, the pre-crystallized polyester resin can be solid-phase polymerized at a temperature of about 150 to 300 ° C and under an inert gas. More specifically, the solid phase polymerization may be carried out at a temperature of about 150 to 250 DEG C, preferably about 170 to 250 DEG C, and the solid phase polymerization may be carried out at a temperature in the above-mentioned range for a certain period of time. In addition, the inert gas may be a nitrogen gas, and may be solid-phase polymerized for about 1 to 40 hours.

As described above, the polyester prepolymer prepared through the step of polymerizing a dicarboxylic acid and a glycol in the presence of the antimony-based catalyst and phosphorus compound to prepare a polyester prepolymer has a high specific gravity of 0.65 dl / g or more The degree of surface crystallinity can be kept low in the pre-crystallization step, so that by-products generated as the reaction proceeds in the solid-phase polymerization step can be easily removed, and the reaction rate can be accelerated.

Accordingly, the method for producing a polyester resin for a tire cord according to one embodiment of the present invention is characterized in that it can be applied to tire cords in the range of 1.0 to 1.4 dl / g A polyester resin having an intrinsic viscosity can be produced.

The polyester produced according to the method for producing a polyester resin for a tire cord in one embodiment may be preferably polyethylene terephthalate. That is, polyethylene terephthalate can be prepared by using terephthalic acid as a dicarboxylic acid and ethylene glycol as a glycol according to the production method of the polyester resin.

INDUSTRIAL APPLICABILITY According to the present invention, there can be provided a method for producing a polyester resin for a tire cord having a linear uniform internal structure and having improved shape stability and heat resistance, and a polyester resin obtained therefrom. The polyester resin for a tire cord can minimize the deformation of the shape of the tire due to excellent shape stability and can effectively support the overall load of the vehicle. Therefore, the tire cord is preferably used for the use of a body fly of an air-inflated tire, etc., so that the adjustability and ride comfort of the vehicle can be improved.

1 is a partially cutaway perspective view showing a structure of a general tire.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

[ Example  And Comparative Example ]: Production of polyester resin

The esterification reactor was charged with 1620 kg (9.75 kmole) of terephthalic acid, 597 kg (9.62 kmole) of ethylene glycol, and an antimony catalyst. The esterification reaction was carried out at a pressure of 1.5 kg / cm 2 G and a temperature of 255 ° C. for 4 hours. After the completion of the esterification reaction with the water generated during the reaction, ethylene glycol, which is generated further, was separated through the distillation column. Phosphoric acid was added as a heat-resistant agent to the reactants of the esterification reaction thus prepared in the amounts shown in Table 1 below, and a polycondensation reaction was carried out at 280 DEG C under high vacuum of 0.3 torr for 6 hours to prepare polyethylene terephthalate prepolymer.

The surface of the thus prepared polyethylene terephthalate prepolymer was subjected to preliminary crystallization at a temperature of 170 캜 for about 2 hours, followed by solid-state polymerization at a temperature of 225 캜 for 4 hours and a temperature of 190 캜 for 30 hours under a nitrogen gas To prepare a final polyethylene terephthalate resin.

The intrinsic viscosity of the polyethylene terephthalate prepolymer was 0.65 dl / g to 0.68 dl / g as shown in Table 1 below, and the polyethylene terephthalate resin prepared by solid phase addition showed an intrinsic viscosity of 1.0 dl / g level .

[ Experimental Example ] Measurement of physical properties of polyester resin

(1) Measurement of linearization degree

The linearity of the polyester resin prepared in the above Examples and Comparative Examples was measured using a SEC-MALS / Viscostar apparatus. The pulverized polyester resin sample was dissolved in an OCP / Chloform (1: 4) ml and then filtered and injected into the instrument. The column used was Mixed (or Linear) Column (Various size) and the injection amount was 500 uL. The degree of linearization is the slope of the measured values when the X axis is the molar mass (Mw, g / mol) and the Y value is the average hydrodynamic radius (nm) The inclination value increases.

(2) Measurement of crystallization rate

The polyethylene terephthalate prepolymer prepared by melt polymerization was made into a sample for DSC measurement. The sample was then heated from room temperature to 290 ° C at a rate of 200 ° C / min, held for 3 minutes, and then cooled down to 210 ° C at a rate of 200 ° C / ) For 15 minutes. At this time, the time from when the temperature starts to decrease at 290 ° C until the absolute value of the exothermic peak appears on the DSC is measured at the crystallization rate.

The polyethylene terephthalate polymer obtained by solid-phase polymerization of the polyethylene terephthalate prepolymer was measured in the same manner as the crystallization rate measuring method of the prepolymer but kept at 210 ° C to 190 ° C.

(3) Determination of crystallinity

Crystallinity was measured by density gradient method. The density of the tube used in the experiment was obtained by using DC-2 product of LLOYD Co., Ltd. The calibration curve was made by using 4 glass plots and the density was measured by placing solid-state polyethylene terephthalate resin in the density tube. The crystallinity was calculated by the following formula (1).

[Chemical Formula 1]

ρ _c = 100% Density of crystalline polymer

ρ _a = density of amorphous polymer

ρ = density of the sample to be measured

(4) Intrinsic viscosity measurement

2 g of a polyester resin prepared by melt polymerization in the above Examples and Comparative Examples was added to 25 ml of 2-chlorophenol and dissolved in a thermostatic bath at 100 ° C for 60 minutes, transferred to an Ostwald viscometer, Minute, and the falling seconds of the solution can be obtained by using a viscometer and an aspirator. The number of drops of the solvent was also determined by the same method, and then the intrinsic viscosity (I.V.) was calculated by the following equations (1) and (2). In the following equation, C represents the concentration of the sample.

[Equation 1]

R.V. = Samples falling in water / solvent drops in seconds

[Equation 2]

IV (intrinsic viscosity) = 1/4 (RV-1) / C + 3/4 (in RV / C)

(5) Measurement of low shear melt viscosity

The polyethylene terephthalate prepolymer and the resin were melted at 290 ° C for 5 minutes under nitrogen, and then the melt viscosity of the polyethylene terephthalate prepolymer and shear rate was measured by Flow-Linear Sweep using Discovery HR-2 from TA Instruments. At this time, a 25 mm parallel plate was used, and the interval between the plates was 1050 μm. The melt viscosity values of the measured values at a shear rate of 10 S ^-1 are shown in Table 1 below.

Furtherance Polyethylene terephthalate prepolymer Sb content (ppmw) P content (ppmw) Intrinsic viscosity
(dl / g) Crystallization speed
(Sec) Linearization degree
(Nm * mol / g) Low shear melting point
(Pa · S) Example 1 180 30 0.65 250 0.43 207 Example 2 150 15 0.65 200 0.46 167 Example 3 150 0 0.65 180 0.50 159 Example 4 130 10 0.65 277 0.45 215 Example 5 130 0 0.65 222 0.46 171 Example 6 100 0 0.65 250 0.45 180 Example 7 180 30 0.68 264 0.47 227 Example 8 150 15 0.68 210 0.51 218 Example 9 150 0 0.68 196 0.53 209 Example 10 130 10 0.68 299 0.46 240 Example 11 130 0 0.68 235 0.50 220 Example 12 100 0 0.68 283 0.47 234 Comparative Example 1 200 40 0.65 277 0.35 218 Comparative Example 2 200 30 0.65 262 0.37 215 Comparative Example 3 180 40 0.65 271 0.34 221 Comparative Example 4 90 0 0.65 301 0.33 222 Comparative Example 5 200 40 0.68 329 0.34 245 Comparative Example 6 200 30 0.68 301 0.42 242 Comparative Example 7 180 40 0.68 275 0.40 Comparative Example 8 90 0 0.68 331 0.36

Polyethylene terephthalate resin Crystallinity (%) Crystallization rate (Sec) Linearization degree (nm * mol / g) Example 1 - 397 0.50 Example 2 - 401 0.53 Example 3 58.3 198 0.63 Example 4 - 266 0.49 Example 5 - 249 0.50 Example 6 - 370 0.47 Example 7 - 351 0.55 Example 8 - 323 0.64 Example 9 56.3 210 0.65 Example 10 - 244 0.59 Example 11 - 225 0.61 Example 12 - 301 0.50 Comparative Example 1 - 522 0.39 Comparative Example 2 58.0 545 0.49 Comparative Example 3 - 437 0.43 Comparative Example 4 - 633 0.42 Comparative Example 5 - 528 0.39 Comparative Example 6 56.1 433 0.45 Comparative Example 7 - 557 0.42 Comparative Example 8 - 657 0.41

As shown in Table 1, the polyester prepolymer prepared according to the method for producing a polyester resin for a tire cord in one embodiment described above had an intrinsic viscosity of 0.65 dl / g or more, The ester resin showed an intrinsic viscosity of 1.0 dl / g. In addition, the polyester resin prepared in the above example exhibited a crystallization speed remarkably faster than that of the comparative example, and showed a degree of linearization of 0.40 or more. In the case of a resin having a high degree of linearization, a viscosity value at a low shear was lower than that of a resin having a low degree of linearization.

From this, it is possible to produce a polyester prepolymer having a high intrinsic viscosity by using less catalyst and a phosphorus compound as in the above-mentioned embodiment, and it is possible to produce a polyester prepolymer obtained by solid phase polymerization under mild conditions, It can be confirmed that the degree of linearization is high, the internal structure is uniform, and the shape stability is excellent.

Claims (18)

Wherein the aromatic divalent functional group and the divalent aliphatic functional group comprise an ester repeating unit connected through an ester bond,
100 ppmw to 180 ppmw of antimony (Sb) and 30 ppmw of phosphorus (P)
Wherein the ratio of the average hydrodynamic radius to the weight average molecular weight is 0.40 nm * mol / g or more.
The method according to claim 1,
Wherein the time at which the absolute value of the exothermic peak appears on the DSC at a maximum value within 400 seconds when the temperature is lowered at a rate of 200 ° C / min from 290 ° C to 190 ° C.
The method according to claim 1,
A polyester resin for a tire cord having a polymer crystallinity of 50% to 60%
[Chemical Formula 1]

In the formula (1), X is the degree of polymer crystallization,
ρ _c is the density of the 100% crystalline polymer,
ρ _a is the density of the amorphous polymer,
and rho is the density of the ester resin for tire cords.
The method according to claim 1,
A polyester resin for a tire cord having an intrinsic viscosity of 1.0 to 1.4 dl / g.
Reacting a dicarboxylic acid and a glycol in the presence of an antimony catalyst to form a polyester prepolymer; And
And solid-phase polymerizing the polyester prepolymer,
Wherein the antimony-based catalyst comprises 100 ppm to 180 ppmw of antimony relative to the total amount of the dicarboxylic acid and the glycol.
6. The method of claim 5,
The step of forming the polyester prepolymer may include an antimony catalyst; And a phosphorus compound containing phosphorus of 30 ppm or less based on the total amount of the dicarboxylic acid and the glycol.
6. The method of claim 5,
The step of forming the polyester prepolymer
Esterifying the dicarboxylic acid component and the glycol component; And polycondensation of the reaction product of the esterification reaction.
6. The method of claim 5,
The dicarboxylic acid may be selected from the group consisting of terephthalic acid, oxalic acid, malonic acid, azelaic acid, fumaric acid, pimelic acid, suberic acid, ), Isophthalic acid, dodecane dicarboxylic acid, naphthalene dicarboxylic acid, biphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, But are not limited to, 1,4-cyclohexane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, succinic acid, glutaric acid, Adipic acid, sebacic acid, 2,6-naphthalene dicarboxylic acid, 1,2-norbornane dicarboxylic acid, 1,3-naphthalene dicarboxylic acid, Cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, It is also possible to use a mixture of Cyclobutane dicarboxylic acid, Cyclohexane dicarboxylic acid, Sodium sulfoisophthalic acid, 5-Potassium Sulfoisophthalic acid, sulfosophthalic acid, 5-lithium sulfoisophthalic acid, and 2-sodium sulfoterephthalic acid. 7. A method for producing a polyester resin for tire cords, comprising the steps of:
6. The method of claim 5,
The glycol may be selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, Butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,3-propylene glycol, diethylene But are not limited to, diethylene glycol, triethylene glycol, cyclohexane diol, 1,3-cyclohexane diol, 1,4-cyclohexane diol, Propanediol, 1,6-hexanediol, neopentyl glycol, tetramethylcyclobutanediol, 1,4-cyclohexane diethanol, 1,10-deca Decamethylene glycol, 1,12-dodecanediol, polyoxyethylene glycol, polyoxyethylene glycol, Glycol (Polyoxymethylene glycol), polyoxytetramethylene glycol (Polyoxytetramethylene glycol), glycerol and a method for producing comprising at least one selected from the group consisting of (Glycerol), the polyester resin for a tire cord.
6. The method of claim 5,
Wherein the reaction of the dicarboxylic acid and the glycol is carried out at a temperature of 200 to 300 캜 for 6 to 20 hours.
6. The method of claim 5,
Wherein the polyester prepolymer prepared by the polymerization reaction of the dicarboxylic acid and the glycol has an intrinsic viscosity of 0.65 dl / g or more.
6. The method of claim 5,
Wherein the polyester prepolymer has a temperature at which the maximum value of the exothermic peak appears on DSC within 300 seconds when the temperature is lowered at a rate of 200 ° C / min from 290 ° C to 210 ° C. Way.
In the fifth aspect,
The polyester prepolymer has a melt viscosity of 50 to 500 Pa · S at a shear rate of 10 S ^{- 1} .
6. The method of claim 5,
Wherein the antimony-based catalyst comprises at least one compound selected from the group consisting of antimony acid antimony, antimony glycolate, antimony triacetate, and antimony trioxide (Sb ₂ O ₃ ).
The method according to claim 6,
The phosphorus compound may be selected from the group consisting of phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, phenylphosphine and 2-carboxylethylphenylphosphinic acid Wherein the polyester resin comprises at least one compound selected from the group consisting of a carboxylic acid, a carboxylic acid, and a carboxylic acid.
6. The method of claim 5,
The step of subjecting the polyester prepolymer to solid-
Further comprising the step of pre-crystallizing the polyester prepolymer at a temperature of 100 ° C to 250 ° C.
17. The method of claim 16,
Wherein the solid phase polymerization of the polyester prepolymer comprises solid phase polymerization of the preliminarily crystallized polyester resin under an inert gas at a temperature of from 150 캜 to 300 캜.
6. The method of claim 5,
Wherein the polyester resin is polyethylene terephthalate.

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