KR20080043587A - Copolyester resin and articles using the same - Google Patents

Abstract

A copolyester resin is provided to exhibit good transparency, high melt viscosity and melt strength, and to improve moldability than the conventional copolyester resins. A copolyester resin includes: a dicarboxylic acid component comprising terephthalic acid; and a diol component comprising 20-80mol% of 1,4-cyclohexanedimethanol, 5-15mol% of 2,2-oxybisethanol represented by the following formula 1, and the balance of ethylene glycol to provide 100mol% of the total diol components. The copolyester resin further comprises 0.05-0.5mol% of polyfunctional monomer relative to the dicarboxylic acid component.

Description

Copolyester resin and molded products using same {Copolyester resin and articles using the same}

The present invention relates to a copolyester resin and a molded article using the same. More specifically, the present invention relates to a co-polyester resin mainly composed of terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, 2,2-oxybisethanol and, optionally, a multifunctional monomer and a molded article using the same. It is about.

Recently, co-polyester resins copolymerized with 1,4-cyclohexanedimethanol have become commercial polyesters used as important materials in the fields of packaging materials, molded articles, films, and the like.

As one such example, US Pat. No. 5,340,907 and US Pat. No. 5,681,918 disclose the use of copolyester resins copolymerized with 1,4-cyclohexanedimethanol and methods for their preparation.

In general, a method of preparing a copolyester resin comprises terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol as a raw material, and adding a stabilizer and a catalyst to perform an esterification reaction and a polycondensation reaction.

However, these general polyester resins have a low melt viscosity for injection molding and sheet forming using calender rolls, but relatively low for use in extrusion blow molding of large-capacity bottles. .

In this regard, US Pat. Nos. 4,217,440 and 4,983,711 disclose methods for increasing melt viscosity by adding additives having multifunctional groups, such as trifunctional groups, in extrusion blow molding. In more detail, 0.05-0.5 mol% of polyfunctional monomers, such as trimellitic acid and pentaerythritol, are added to co-polyester resin which has other diols, such as ethylene glycol and 1, 4- cyclohexane dimethanol, with respect to terephthalic acid, It is a method of improving melt viscosity. In this case, the molecular weight is increased by branching (melting) to increase the melt viscosity, but this causes the melt pressure to increase during molding.

In the case of the copolyester resin to which the polyfunctional monomer is added, the molecular weight is increased due to the above-mentioned branching effect, so that the melt pressure is higher than that of the general copolyester polyester resin during extrusion blow molding. If the melt pressure is high, the efficiency of shortening the cycle time by increasing the RPM for productivity improvement and shortening the working time cannot be expected, and since the margin of the molding temperature range is small, the melt temperature and strength can be further improved by lowering the molding temperature. The disadvantage is that no good results can be obtained.

Accordingly, the present invention solves the above problems and studies to prepare a polyester resin having properties superior to the copolymerized polyester resin according to the prior art, as a result, 1,4-cyclohexane dimethanol and optionally a multifunctional monomer In the preparation of the copolymerized polyester resin, by further copolymerizing with 2,2-oxybisethanol, it is possible to lower the melt pressure during molding. As a result, a copolyester resin having excellent moldability was obtained, and the present invention was completed based on this.

Accordingly, one aspect of the present invention is to provide a copolyester resin having improved moldability than conventional copolyester resins.

Another aspect of the present invention is to provide an extrusion blow molded product using the copolymerized polyester resin.

Co-polyester resin according to a preferred embodiment of the present invention,

Dicarboxylic acid components including terephthalic acid;

20 to 80 mol% of 1,4-cyclohexanedimethanol, 5 to 15 mol% of 2,2-oxybisethanol represented by the following formula (1), and the rest includes ethylene glycol so that the sum of all diol components is 100 mol% A diol component;

Characterized in that it comprises a.

The copolyester resin may further comprise 0.05 to 0.5 mol% of a multifunctional monomer with respect to the dicarboxylic acid component. The polyfunctional monomer is preferably trimellitic acid, trimellitic anhydride, hemimeltic acid, hemimeltic anhydride, trimesic acid, tricavalic acid, trimethylolpropane, trimethylolethane , Glycerin, pentaerythritol and combinations thereof.

The copolyester resin also preferably has a melt pressure of 90 bar or less.

Extruded blow molded article according to a preferred embodiment of the present invention is formed by extrusion blow molding the copolymer polyester resin.

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

As described above, in the present invention, 1,4-cyclohexanedimethanol is copolymerized by adding 2,2-oxybisethanol in the preparation of a copolymerized polyester resin, thereby having a low melt pressure during extrusion blow molding. An excellent copolymerized polyester resin and a molded product using the same are provided.

Copolyester resin according to the present invention is prepared through the first step of the esterification reaction and the second step of the polycondensation reaction.

The first step, the esterification reaction may be carried out in a batch or continuous manner, and each raw material may be added separately, but it is most preferable to make a dicarboxylic acid component into a diol component in a slurry form. .

More specifically, first, a dicarboxylic acid component containing terephthalic acid and a diol component containing ethylene glycol, 1,4-cyclohexanedimethanol and 2,2-oxybisethanol are reacted, and optionally polyfunctional. The monomer is further added to react.

In this case, it is preferable to add the diol component so that the content of the diol component is 1.2 to 3.0 in a molar ratio, and to perform the esterification under the conditions of 230 to 260 ° C and 1.0 to 3.0 kg / cm 2, but not limited thereto. It doesn't happen. Preferably, the said esterification temperature is 240-260 degreeC, More preferably, it is 245-255 degreeC. In addition, the esterification time is usually about 100 to 300 minutes, which may be appropriately changed depending on the reaction temperature, pressure and the molar ratio of the diol component to the dicarboxylic acid component used.

In addition to the terephthalic acid, the dicarboxylic acid component used for the purpose of improving the physical properties in the present invention isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, succinic acid, gluta Lactic acid, adipic acid, sebacic acid, 2,6-naphthalenedicarboxylic acid, and the like, but are not particularly limited thereto.

Diol components used in the present invention include 1,4-cyclohexanedimethanol, ethylene glycol and 2,2-oxybisethanol.

The 1,4-cyclohexane dimethanol is used to improve the moldability or other physical properties of the homopolymer based only on terephthalic acid and ethylene glycol, 1,4-cyclohexane dimethanol can be used as cis- , Trans-, or a mixture of two isomers, and the amount thereof is used in an amount close to the desired mole percent of the final copolymerized polyester resin. Preferably, 20 parts of the total diol component is used to prevent moldability due to crystallization. It is good that it is -80 mol%.

2,2-oxybisethanol used in the present invention is represented by the following Chemical Formula 1 as a component for reducing the melt pressure during extrusion blow molding of the copolymer resin:

Formula 1

In this case, the amount of the 2,2-oxybisethanol is preferably 5 to 15 mol% of the diol component, and when the amount is less than 5 mol%, the effect of lowering the pressure of melting due to the addition of 2,2-oxybisethanol is confirmed. It is difficult to do it, and if it exceeds 15 mol% there is a problem that the reactivity is inferior. In particular, low melt pressure values of 90 bar or less can be expected in extrusion blow molding by adding and copolymerizing the 2,2-oxybisethanol in the preparation of the polyester resin. When molding has a low melt pressure of 90bar or less, the RPM of the molding machine is increased to shorten the cycle time, thereby improving productivity. In addition, since there is a margin in the molding temperature range, it is possible to obtain excellent results that can further improve the melt viscosity and strength by lowering the molding temperature.

Meanwhile, ethylene glycol, which is one of the diol components of the present invention, is added so that the sum of all diol components is 100 mol% in consideration of the amounts of 1,4-cyclohexanedimethanol and 2,2-oxybisethanol.

As other diol components, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, and 1,2-cyclo Hexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and the like can be further used.

The polyfunctional monomer optionally usable in the present invention is a crosslinking agent component for further improving the extruded blow moldability, and includes trimellitic acid, trimellitic hydride, hemimeltic acid, hemimeltic anhydride and trimesic acid. , Tricavalic acid, trimethylolpropane, trimethylolethane, glycerin and pentaerythritol, and the like, but are not limited thereto.

In this case, the amount of the polyfunctional monomer is preferably 0.05 to 0.5 mol% with respect to the dicarboxylic acid, if the amount is less than 0.05 mol% is not effective to reach the melt strength (melt strength) useful for extrusion blow molding. If it exceeds 0.5 mol%, transparency is lowered due to active crosslinking, and thus a desired molded product cannot be obtained.

The esterification reaction does not require a catalyst, but may be optionally added to reduce the reaction time.

After the first step of the above-mentioned esterification reaction is completed, the second step of the polycondensation reaction is carried out. The polycondensation catalyst, stabilizer and colorant are generally used in the polycondensation reaction of the polyester resin. May optionally be used.

Polycondensation catalysts usable in the present invention include, but are not limited to, titanium, germanium and antimony compounds.

The titanium-based catalyst is generally used as a polycondensation catalyst of a polyester resin copolymerized with 1,4-cyclohexanedimethanol by 15% or more by weight of terephthalic acid, and even when a small amount is used in comparison with an antimony-based catalyst It is possible and also has the advantage of lower cost than germanium-based catalyst.

Titanium-based catalysts usable in the present invention include tetraethyl titanate, acetyltripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetrabutyl titanate, polybutyl titanate, 2-ethylhexyl titanate, octylene Glycol titanate, lactate titanate, triethanolamine titanate, acetylacetonate titanate, ethyl acetoacetic ester titanate, isostearyl titanate, titanium dioxide, titanium dioxide and silicon dioxide co-precipitates, titanium dioxide and zirconium dioxide And coprecipitates.

In this case, since the amount of the polycondensation catalyst affects the color of the final polymer, the amount of polycondensation catalyst may vary depending on the desired color and the stabilizer and colorant used. Preferably, the amount of polycondensation catalyst is 1 to 100 ppm based on the amount of titanium based on the weight of the final polymer. More preferably, 1-50 ppm is good and 10 ppm or less is preferable based on a silicon element amount. At this time, if the amount of titanium element is less than 1ppm can not reach the desired degree of polymerization, if it exceeds 100ppm the color of the final polymer is yellow and the desired color cannot be obtained.

In addition, stabilizers and coloring agents and the like can be used as other additives.

Stabilizers usable in the present invention typically include phosphoric acid, trimethyl phosphate, triethyl phosphate, triethyl phosphonoacetate, and the like, and the amount of the stabilizer may be 10 to 100 ppm relative to the weight of the final polymer based on the small amount of people. At this time, if the addition amount of the stabilizer is less than 10ppm it is difficult to obtain the desired bright color, if it exceeds 100ppm there is a problem that does not reach the desired high polymerization degree.

In addition, the colorants usable in order to improve the color in the present invention include conventional colorants such as cobalt acetate and cobalt propionate, the addition amount is preferably 0 to 100ppm relative to the final polymer weight.

In addition to the colorant, conventionally known organic compounds may be used as the colorant.

On the other hand, the second condensation reaction is carried out after the addition of these components is preferably carried out under reduced pressure conditions of 260 ~ 290 ℃ and 400 ~ 0.1mmHg, but is not limited thereto.

The polycondensation step is carried out for the required time until the desired intrinsic viscosity is reached, the reaction temperature is generally 260 ~ 290 ° C, preferably 260 ~ 280 ° C, more preferably 265 ~ 275 ° C.

In addition, the polycondensation reaction is carried out under a reduced pressure of 400 ~ 0.1mmHg in order to remove the diol as a by-product to obtain a polyester resin copolymerized with 1,4-cyclohexanedimethanol.

As described above, the copolyester resin according to the present invention has excellent moldability due to low melt pressure during the molding process. Therefore, such a copolyester resin may be molded through an extrusion hollow process to obtain an extruded blow molded product having excellent moldability.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples, but the scope of the present invention is not limited thereto.

The physical properties shown in the following Examples and Comparative Examples were measured in the following manner:

◎ Transparency: Measured using Haze-meter manufactured by Nippon Denshoku, Japan.

◎ Melt Viscosity: Measured by parallel plate type in shear rate (1 / s) = 1 region using Physica Rheometer of Physica, USA.

◎ Melt strength: measured using Extrusion Blow Molding from Bekum, Germany. The machine's RPM is 20, the cycle time is 17 seconds, the die diameter is 30 millimeters, the extruder temperature and the die temperature are 195-220 ℃ and 190-205 ℃ for each section. Measure the diameter of the 100 millimeter lower end from the die of the molding machine.

The melt strength (%) is calculated using the following equation:

(A-D) / D × 100

Where A is the diameter after 10 centimeter extrusion from the die and D is the diameter of the die. Therefore, the percentage melt strength is negative when A is less than D and positive when D is greater than D.

◎ Melting pressure: measured by Extrusion Blow Molding of Bekum, Germany. After about 20 kg of the type of sample to be measured is put into the molding machine, after 20 minutes of stabilization time, the difference between the setting internal temperature and the actual internal temperature of the molding machine is less than ± 1 ° C. Measure the average value when less than 4 bar.

Example 1

Based on 6 moles of terephthalic acid, 1.8 g of trimellitic acid was added to a polyester resin copolymerized with 277 g of 1,4-cyclohexanedimethanol and 466 g of ethylene glycol, and 40 g of 2,2-oxybisethanol was added to a stirrer and an outflow condenser. The reaction is carried out while gradually raising the temperature to 255 ℃ while mixing in a 3L reactor equipped.

At this time, the generated water is discharged out of the system to ester reaction, and when the generation of water, the outflow is finished, the contents are transferred to a polycondensation reactor equipped with a stirrer, a cooling condenser and a vacuum system.

Add 0.5 g of tetrabutyl titanate to the esterification reaction, add 0.4 g of triethylphosphate, add 0.5 g of cobalt acetate, and increase the internal pressure from 240 ° C to 275 ° C. Ethylene glycol is removed through a low vacuum reaction at 50 mmHg for 40 minutes at low pressure, and then gradually decompressed to 0.1mmHg until the desired intrinsic viscosity is reached under high vacuum, and then discharged and cut into chips.

The transparency, intrinsic viscosity, melt viscosity, melt pressure and melt strength together with the reaction conditions of the 1,4-cyclohexanedimethanol copolyester resin thus prepared are shown in Table 1 below.

Example 2

Except for adding 84 g of 2,2-oxybisethanol, the same process as in Example 1 was carried out. The clarity, intrinsic viscosity, melt viscosity, melt pressure and melt strength together with the reaction conditions are shown in Table 1 below. It was.

Example 3

Except not adding trimellitic acid used as a multifunctional monomer was carried out in the same manner as in Example 1, the transparency, intrinsic viscosity, melt viscosity, melt pressure and melt strength with the reaction conditions are shown in Table 1 Shown in

Comparative Example 1

Except not adding 2,2-oxybisethanol was carried out in the same manner as in Example 1, and the transparency, intrinsic viscosity, melt viscosity, melt pressure and melt strength with the reaction conditions are shown in Table 1 below. It was.

Comparative Example 2

Except for the addition of 2,2-oxybisethanol and trimellitic acid as a polyfunctional monomer, it was carried out in the same manner as in Example 1, with the reaction conditions of transparency, intrinsic viscosity, melt viscosity, melting pressure and Melt strength is shown in Table 1 below.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 additive 40 g of 2,2-oxybisethanol + 1.8 g of trimellitic acid 84 g of 2,2-oxybisethanol + 1.8 g of trimellitic acid 40 g of 2,2-oxybisethanol 1.8 g of trimellitic acid - Intrinsic viscosity (IV) (dl / g) 0.78 0.77 0.77 0.77 0.78 Transparency (Haze) 1.0 or less 1.0 or less 1.0 or less 1.0 or less 1.0 or less Melt pressure (bar) 85 ± 4 70 ± 4 82 ± 4 105 ± 4 94 ± 4 Melt viscosity (Pa.s) (275 ℃) 2210 2730 800 2100 1090 Melt strength (%) 20.8 19.2 10.0 19 10.5

As can be seen from the above examples and comparative examples, in the present invention, a dicarboxylic acid component containing terephthalic acid, 1,4-cyclohexanedimethanol, a diol containing ethylene glycol and 2,2-oxybisethanol By copolymerizing the components, since the melt pressure during molding is reduced compared to the copolymerized polyester produced by the conventional method, the productivity can be improved by increasing the RPM to shorten the cycle time, and the molding temperature can be obtained because there is a margin in the molding temperature range. By lowering it can be obtained excellent results that can further improve the melt viscosity and strength.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

Claims (5)

Dicarboxylic acid components including terephthalic acid; 20 to 80 mol% of 1,4-cyclohexanedimethanol, 5 to 15 mol% of 2,2-oxybisethanol represented by the following formula (1), and the rest includes ethylene glycol so that the sum of all diol components is 100 mol% A diol component; Copolymerized polyester resin comprising: Formula 1

The copolyester resin according to claim 1, wherein the copolyester resin further comprises 0.05 to 0.5 mol% of a multifunctional monomer with respect to the dicarboxylic acid component. The method of claim 2, wherein the polyfunctional monomer is trimellitic acid (trimellitic acid), trimellitic anhydride (hemimellitic acid), hemimelitic acid, anhydrous hemimelitic acid, trimesic acid, tricavalic acid, trimethylolpropane, Co-polyester resin, characterized in that selected from the group consisting of trimethylol ethane, glycerin, pentaerythritol and combinations thereof. The copolyester resin of claim 1, wherein the copolyester resin has a melting pressure of 90 bar or less. An extruded blow molded article formed by extrusion blow molding the co-polyester resin according to claim 1.