KR100415631B1 - A method for preparing polyester copolymer resin for laminating film and polyester copolymer resin having sulfone acid side chain produced thereby - Google Patents

Abstract

The present invention relates to a method for producing a polyester copolymer resin for a laminate film and a polyester copolymer resin having a sulfonic acid side chain in the polymer main chain prepared therefrom,

(a) reacting terephthalic acid derivative of formula (1), ethylene glycol of formula (2) and 5-sulfoisophthalic acid derivative of formula (3) by heating from 180 ° C. to 205 ° C. under a metal acetate catalyst;

(b) condensation polymerization of the reaction product of step (a) at a pressure of from 100 torr to 10 torr while heating from 205 ° C. to 280 ° C. for about 1 hour; And

(c) polymerizing poly (ethylene 5-sulfoisophthalate-co-terephthalate) of formula 6 by continuously performing the reaction of step (b) while maintaining the vacuum at 1 to 2 torr at 280 ° C. It is provided; a method for producing a polyester copolymer resin for a laminate film consisting of.

HOCH ₂ CH ₂ OH

(However, in the formula 1 to 3, R ₁ and R ₂ are each independently selected from H or C _{1 to} C ₁₀ alkyl group,

M ⁺ is selected from alkali metal ions including Li ⁺ , Na ⁺ or K ⁺ ,

In Formula 6, k + m is 90 mol% or more, and l + n is 10 mol% or less.)

According to the above, it is possible to synthesize a polyester copolymer resin having a chemical composition suitable for the lamination process of the metal container by improving the adhesion to the metal surface to improve the workability, and environmental pollution and environment that was a problem in the conventional lacquer coating Hormonal effects can be ruled out.

Description

A method for preparing a polyester copolymer resin for a laminate film and a polyester copolymer resin having a sulfonic acid side chain in a polymer main chain prepared therefrom. THEREBY}

The present invention relates to a method for producing a polyester copolymer resin for a laminate film and to a polyester copolymer resin having a sulfonic acid side chain in the polymer main chain prepared therefrom, and more particularly to a polyester having a sulfonic acid side chain in the polymer main chain. A method for producing a copolymer by polycondensation reaction.

Due to the industrial development of the world, interest in the natural environment is increasing day by day, and in recent years, due to environmental hormones, production and usage of metal containers laminated with polymer resin films instead of lacquer coated metal containers has been increasing. The trend is steadily increasing.

This is to remove the amount of harmful organic solvents generated during lacquer coating, and to remove the effects of environmental hormones that can be eluted from the finished product.

In addition, the laminated film metal container has better permeability of moisture and contents than the lacquer coated metal container, and thus has excellent storage properties, including food and beverage, and dissolution of the metal due to contact or reaction with the contents. It has the advantage of no alteration and side effects.

The polymer resin film used in the manufacture of the laminate container is an important factor that determines the performance of the metal container. It is excellent in workability and should not be destroyed during the forming process of the metal container. It should be able to store drinks and other contents for a long time because of its excellent permeability.

As a polymer resin material satisfying such conditions, aromatic polyester copolymer resins having excellent antipermeability of air and moisture and excellent solvent resistance have been widely used.

In addition, the adhesion to the metal surface can be improved by introducing a functional group having an ionic form into the polymer backbone. As a functional group having a conventional ionic form, a sulfonic acid group is used to contact SO ₃ ^- with iron to form a chemical bond. As a result, improved adhesion can be expected.

However, in this case, as a side reaction during the polymerization reaction, a polyester copolymer containing a large amount of diethylene glycol units is produced. As such, the amount of diethylene glycol is known to increase as the amount of sulfonic acid increases, but diethylene glycol is increased by 4 to 35% than general polyethylene terephthalate.

As described above, copolymers containing a large amount of diethylene glycol units have a high melt viscosity, resulting in poor processability during film production, and the resulting diethylene glycol acts as a factor that can change the physical properties of the polymer resin, thereby melting and crystallinity of the polymer resin. There is a problem that inhibits.

Therefore, there is a need for the development of a new polymerization method that can control the amount of diethylene glycol units in the polyester copolymer chain produced by side reactions during condensation polymerization to an appropriate amount or less.

Accordingly, an object of the present invention is to provide a method for producing a polyester copolymer resin excellent in adhesion.

Another object of the present invention is to improve the melting point and crystallinity is improved physical properties It is to provide a method for producing a polyester copolymer resin.

Another object of the present invention is to provide a method for producing a polyester copolymer having improved workability by controlling the content of diethyl glycol units produced by side reactions during polycondensation of the polyester copolymer to an appropriate amount or less.

Furthermore, another object of the present invention is to produce a polyester copolymer having a sulfonic acid group in the polymer main chain by the polyester copolymer production method.

According to the first aspect of the present invention,

(a) reacting terephthalic acid derivative of formula (1), ethylene glycol of formula (2) and 5-sulfoisophthalic acid derivative of formula (3) by heating from 180 ° C. to 205 ° C. under a metal acetate catalyst;

(b) condensation polymerization of the reaction product of step (a) at a pressure of from 100 torr to 10 torr while heating from 205 ° C. to 280 ° C. for about 1 hour; And

(c) polymerizing poly (ethylene 5-sulfoisophthalate-co-terephthalate) of formula 6 by continuously performing the reaction of step (b) while maintaining the vacuum at 1 to 2 torr at 280 ° C. It is provided; a method for producing a polyester copolymer resin for a laminate film consisting of.

[Formula 1]

[Formula 2]

HOCH ₂ CH ₂ OH

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

(However, in the formula 1 to 3, R ₁ and R ₂ are each independently selected from H or C _{1 to} C ₁₀ alkyl group,

M ⁺ is selected from alkali metal ions including Li ⁺ , Na ⁺ or K ⁺ ,

In Formula 6, k + m is 90 mol% or more, and l + n is 10 mol% or less.)

According to the second aspect of the present invention,

The polyester copolymer resin which has a sulfonic acid group side chain in the polymer main chain manufactured from the manufacturing method of the said 1st aspect is provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the present invention, by polycondensation of terephthalic acid derivatives, ethylene glycols and 5-sulfoisophthalate derivatives poly (ethylene 5-sulfoy) in which the amount of diethyl glycol units generated by side reactions during the production of the polyester copolymer is adjusted to an appropriate amount or less Sophthalate-co-terephthalate) copolymers can be prepared.

In the present invention, in preparing a poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer, terephthalic acid derivative of formula 1, ethylene glycol of formula 2 and 5-sulfoisophthalate derivative of formula 3 It reacts by heating from 180 degreeC to 205 degreeC under a catalyst. At this time, the 5-sulfoisophthalate derivative is added at 20 mol% or less.

[Formula 1]

[Formula 2]

HOCH ₂ CH ₂ OH

[Formula 3]

However, in Formulas 1-3, R ₁ and R ₂ are each independently selected from H or C ₁ -C ₁₀ alkyl group,

M ⁺ is selected from alkali metal ions including Li ⁺ , Na ⁺ or K ⁺ and the like.

By the transesterification reaction as described above, a low molecular weight ester mixture in which bishydroxyethylene terephthalate of formula 4 is mixed with bishydroxyethylene 5-sulfoisophthalate of formula 5 is synthesized.

[Formula 4]

[Formula 5]

When the condensation polymerization is carried out to the resultant composite at reduced pressure from 100 to 10 torr while heating from 205 DEG C to 280 DEG C, the condensation polymerization reaction is a reversible reaction as ethylene glycol exits the reaction system by transesterification. The molecular weight of the polymer can be increased by leading to the synthesis of the oligomer.

In this case, the antimony acetate catalyst may be added separately from the step (a). When the antimony acetate catalyst is added, it is preferably used in an amount of 0.06 to 0.10% by weight.

The reaction was then carried out while maintaining the reaction temperature, while maintaining the vacuum at 1 to 2 torr to give a poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer of formula 6.

According to the above, a poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer of the formula (6) containing 10 mol% or less of diethylene glycol in the polymer backbone is prepared.

[Formula 6]

In Formula 6, k + m is 90 mol% or more, and l + n is 10 mol% or less. Thus, the poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer contains up to 10 mol% of diethylene glycol units.

The weight average molecular weights of the said polyester copolymer resin are 5,000-500,000, More preferably, it is 20,000-200,000, Intrinsic viscosity is 0.20-2.00, More preferably, it is 0.40-0.80.

Thus the poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer prepared by the process of the invention can be used for laminate films for metal containers.

The aromatic polyester copolymer resin of the present invention may be specifically produced by the following method.

First, a metal acetate catalyst is added to 2.0-2.4 moles of ethylene glycol based on the total weight of terephthalic acid derivatives and at least 20 mole% of 5-sulfoisophthalate derivatives and the total weight of the terephthalic acid derivatives and 5-sulfoisophthalate derivatives. It reacts at 180-205 degreeC.

Terephthalic acid derivatives usable herein include compounds having the formula (1), wherein R ₁ is H or C _{1 to} C ₁₀ , preferably dimethyl terephthalate or terephthalic acid.

In addition, the 5-sulfoisophthalate derivative is used because -SO ₃ ^- in the sulfonic acid group can form a chemical bond when contacted with iron, which is a material of the container, and thus can be expected to have improved adhesion than a conventional polyester film. the R ₂ of the compound represented by the following formula 3 may be used a yitto H or C ₁ ~ ₁₀ the compound.

In order to reduce the diethylene glycol produced | generated in the final result to 10 mol% or less, it is preferable to use the said 5-sulfoisophthalate below 20 mol%.

In addition, since ethylene glycol reacts with the terephthalic acid derivative in a 2: 1 molar ratio, it is preferable to use 2.0 to 2.4 times molar based on the total weight of the terephthalic acid derivative and the 5-sulfoisophthalate derivative to be treated with ethylene glycol. It is also undesirable to have too much excess since these will produce diethylene glycol.

It is preferable to heat the reaction temperature from 180 ° C. to 205 ° C., but 180 ° C. is a melting point of dimethyl terephthalate. Therefore, it is not meaningful to heat the reaction below. When the temperature is 210 ° C. or higher, ethylene glycol reacts to produce diethylene glycol. It is not desirable because the probability increases. At this time, in order to make uniform temperature match, it is more preferable to stir.

In addition, by heating the reaction from 180 ℃ to 205 ℃ and then separately adding the 5-sulfoisophthalate derivative within the range of 20 mol% or less with the total amount added in advance to reduce the amount of diethylene glycol produced in the resulting product It is preferable because it can.

The metal acetate catalyst to be used is not limited thereto, but Ti, Ga, Sn, Sb, Al, Ce, Co, Pb, Zn, Mn, Mg, and Zn based acetate catalysts may be used, and Zn based acetate catalysts may be used. It is preferable.

The catalytic amount of the metal acetate to be used is not limited to this, but it is preferable to use 0.01 to 0.05% by weight since the polymer can be obtained quickly. The reaction time can be adjusted according to the amount of catalyst used.

The time point at which the reaction performed in step (a) is terminated is determined through the output of methanol, a by-product generated during the production of Chemical Formulas 4 and 5. The oligomers of Formulas 4 and 5 thus prepared serve as monomers for synthesizing the polymeric polyester copolymer in a subsequent process.

In step (b), the mixed product represented by the formulas (4) and (5), which is the resultant product of step (a), is condensation-polymerized under reduced pressure from 100 torr to 10 torr while heating from 205 ° C to 280 ° C.

The heating temperature of 205 degreeC to 280 degreeC is a range which considers that melting | fusing point falls and decomposes with the quantity of 5-sulfoisophthalate, and the reaction temperature is about 50 minutes-about 1 hour.

As described above, when the reaction is performed under reduced pressure from 100 torr to 10 torr, all low molecular weight compounds such as unreacted ethylene glycol, terephthalic acid and diethylene glycol can be removed. In this case, if the pressure is reduced to 10 torr or less, an initial high vacuum atmosphere is created, and thus the oligomers synthesized in the step (a) are released together outside the reaction system.

Here, the antimony acetate catalyst may be used separately from the step (a). The amount thereof is not limited thereto, but it is preferable to use 0.06 to 0.10% by weight based on the weight of the terephthalic acid derivative so that the polymer can be produced quickly.

Then, in step (c) of the present invention, the condensation polymerization reaction is continuously performed while maintaining a vacuum degree of 1 to 2 torr by gradually increasing the vacuum degree at the temperature controlled in step (b). This reaction causes a transesterification reaction so that the ethylene glycol exits the outside of the reaction system, thereby increasing the degree of polymerization of the polymer.

The pressure used here is not limited to 1 to 2 torr. If the pressure is reduced further, a polymer having a higher molecular weight can be produced in a short time.

After completion of the reaction, an inert gas was blown into the reaction vessel, and the product was discharged into cold water through the lower portion of the reaction vessel. Thus, poly (ethylene 5-sulfoi) containing not more than 10 mol% of diethylene glycol to be produced in the present invention was produced. Sophthalate-co-terephthalate) copolymer.

Here, by adding nitrogen, Ar, He, etc. to the reaction vessel as an inert gas, the resulting product can be eluted due to the gas pressure.

The weight average molecular weight of the poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer produced is 5,000 to 500,000, more preferably 20,000 to 200,000.

In addition, the intrinsic viscosity of the copolymer which is related to the molecular weight by the friction of the polymer chain dissolved in the solution phase is 0.20 to 2.00, more preferably 0.40 to 0.80.

As described above, the poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer prepared by the method of the present invention simultaneously controls the content of diethylene glycol units in the copolymer chain to 10 mol% or less. By containing sulfonic acid groups in the side chains, the adhesion to the metal container can be improved to improve processability when used for laminate films, and the physical properties of the copolymer resin itself can be improved by improving melting point and crystallinity.

Hereinafter, the present invention will be described in detail by way of examples compared with general copolymer synthesis methods, but is not limited thereto.

<Example>

Comparative example

99 mole% of dimethyl terephthalate and 1 mole% of dimethyl 5-sulfodimethyl isophthalate, using 2.4 moles of ethylene glycol and zinc acetate dihydrate catalyst for the sum of dimethyl terephthalate and dimethyl 5-sulfoisophthalate 0.025% by weight was added to the reactor and reacted by heating with stirring for 3 hours from 180 ° C to 205 ° C.

The termination of the reaction determines the end point of the reaction through the amount of methanol which is a reaction byproduct. To the synthesized product, 0.08% by weight of an antimony acetate catalyst was added to the reactor based on dimethyl terephthalate and dimethyl 5-sulfoisophthalate and heated from 205 ° C to 250 ° C without any treatment, and then gradually heated to 280 ° C. The reaction was continued for 4 hours while maintaining a vacuum of 1 torr at 280 ° C.

After the reaction, the product was blown with dried nitrogen to the reaction vessel and discharged into cold water through the bottom of the reaction vessel.

The prepared copolymer resin was calculated by using a differential scanning calorimetry (DSC) using a nuclear magnetic resonance spectrum (NMR) to calculate the amount of 5-ethylene sulfo phthalate and the amount of diethylene glycol units produced by side reaction in the formula 6 Intrinsic melting point of the copolymer copolymer resin was measured.

In addition, the heat history of the resin was removed using a differential scanning calorimeter, the heat of fusion was measured while cooling to 10 ℃ / min and then again heated to 5 ℃ / min.

Furthermore, when the heat of fusion of polyethylene terephthalate having 100% crystallinity is 117.59 J / g, the degree of crystallinity was calculated from the measured heat of fusion, and the results are shown in Table 1 below.

Example 1

The method of Comparative Example was repeated except that the reaction was reduced from 100 torr to 10 torr while heating from 205 ° C to 280 ° C, followed by reaction while maintaining 1 torr at 280 ° C.

At this time, the chemical composition, melting point, glass transition temperature, intrinsic viscosity and crystallinity were examined under the same conditions as in Comparative Example 1, and the results are shown in Table 1 below.

Example 2

A method of Comparative Example was prepared except that a mixture of bishydroxyethylene terephthalate and bishydroxy ethylene 5-supoterphthalate was synthesized, and then 1 mol% of dimethyl 5-sulfoisophthalate was separately added and stirred for about 1 hour. Was repeated.

At this time, the chemical composition, melting point, glass transition temperature, intrinsic viscosity and crystallinity were investigated under the same conditions as in Comparative Example 1, and the results are shown in Table 1 below.

Example 3

The method of Example 1 was repeated except that zinc acetate dihydrate catalyst was used at 0.045% by weight relative to the total weight of dimethyl terephthalate and dimethyl 5-sulfoisophthalate and no antimony acetate catalyst was used.

At this time, the chemical composition, melting point, glass transition temperature, intrinsic viscosity and crystallinity were examined under the same conditions as in Comparative Example 1, and the results are shown in Table 1 below.

Example 4

The method of Example 1 was repeated except using 98 mol% of dimethyl terephthalate and 2 mol% of dimethyl 5-sulfodimethyl isophthalate.

At this time, the chemical composition, melting point, glass transition temperature, intrinsic viscosity and crystallinity were examined under the same conditions as in Comparative Example 1, and the results are shown in Table 1 below.

Example 5

The method of Example 3 was repeated except that 99.5 mol% of dimethyl terephthalate and 0.5 mol% of dimethyl 5-sulfoisophthalate were used.

At this time, the chemical composition, melting point, glass transition temperature, intrinsic viscosity and crystallinity were examined under the same conditions as in Comparative Example 1, and the results are shown in Table 1 below.

division Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 5-sulfoisophthalate content (mol%) 1.01 0.99 0.97 1.01 1.96 0.49 Diethylene Glycol Unit Content (mol%) 20.27 6.60 6.15 4.07 5.97 3.53 Melting Point (℃) 216.1 245.7 246.6 249.9 244.4 252.5 Glass transition temperature (℃) 63.4 76.2 76.5 76.6 76.4 76.5 Intrinsic viscosity 0.62 0.64 0.67 0.65 0.64 0.61 Heat of fusion (J / g) 28.54 37.95 38.05 39.0 35.75 39.95 % Crystallinity * 24.3 32.3 32.4 33.2 30.4 34.0

* Crystallinity calculated from the measured heat of fusion when the heat of fusion of polyethylene terephthalate with 100% crystallinity is 117.59 J / g

As shown in the above table, in the comparative example, when 10% of 5-sulfoisophthalic acid derivative is added, about 20 mol% of diethylene glycol side chain in the polyester copolymer is produced. It can be seen that the amount of ethylene glycol produced at 10 mol% or less can be significantly reduced to improve laminate film processing properties.

In addition, it can be seen that the physical properties of the prepared copolymer resin are improved by improving melting point and crystallinity.

On the other hand, as a result of comparing the intrinsic viscosity value associated with the molecular weight, it was possible to produce a copolymer having no difference from the copolymer prepared in the comparative example in molecular weight.

According to the present invention polymerized using a 5-sulfoisophthalate derivative as a comonomer, the content of diethylene glycol units in the copolymer chain is controlled to an appropriate amount in comparison to the general poly (ethylene terephthalate) of the comparative example, By improving the adhesion to the metal container by using it can improve the processability enough to be used for the laminate film to the metal container, and improve the physical properties of the copolymer resin itself by improving the melting point and crystallinity, as well as The effects of lacquer coating, environmental pollution and the effects of environmental hormones can be eliminated.

Claims (6)

(a) 80 mole% or more of the terephthalic acid derivative of the following formula (1), 20 mole% or less of the 5-sulfoisophthalic acid derivative of the formula (3), and the total moles of the terephthalic acid derivative and the 5-sulfoisophthalate derivative. Reacting by heating 2.0-2.4 moles of ethylene glycol of the following formula (2) to a terephthalic acid derivative at a temperature of 180 ° C. to 205 ° C. under 0.01 to 0.05% by weight of a metal acetate catalyst, (b) condensation polymerization of the reaction product of step (a) under reduced pressure from 100 torr to 10 torr while heating from 205 ° C to 280 ° C in the presence of 0.06 to 0.10% by weight of antimony acetate catalyst based on the terephthalic acid derivative; step; And (c) polymerizing poly (ethylene 5-sulfoisophthalate-co-terephthalate) of formula 6 by continuously performing the reaction of step (b) while maintaining the vacuum at 1 to 2 torr at 280 ° C. Method for producing a polyester copolymer resin for a laminate film consisting of [Formula 1] [Formula 2] HOCH ₂ CH ₂ OH [Formula 3] [Formula 4] [Formula 5] [Formula 6] (However, in the formula 1 to 3, R ₁ and R ₂ are each independently selected from H or C _{1 to} C ₁₀ alkyl group, M ⁺ is selected from alkali metal ions including Li ⁺ , Na ⁺ or K ⁺ , In Formula 6, k + m is 90 mol% or more, and l + n is 10 mol% or less.) The method according to claim 1, wherein after the step (a), the 5-sulfoisophthalate derivative is added and reacted within a range such that the total amount of the 5-sulfoisophthalate derivative with the amount used in the step (a) is 20 mol% or less. Manufacturing method The method according to claim 1, wherein the poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer of Formula 6 has a weight average molecular weight of 5,000 to 500,000, and an intrinsic viscosity of 0.20 to 2.00. The method of claim 1, wherein the poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer of Chemical Formula 6 has a weight average molecular weight of 20,000 to 200,000, and an intrinsic viscosity of 0.40 to 0.80. The method of claim 1, wherein the diethylene glycol unit contained in the copolymer of Chemical Formula 6 is 10 mol% or less. A poly (ethylene 5-sulfoisophthalate-co-terephthalate) copolymer of formula 6 prepared according to any one of claims 1 to 5 [Formula 6] (K + m is 90 mol% or more, and l + n is 10 mol% or less.)