KR20050042880A - The organic modification method of clay minerals for polyesters and the preparation method of polyester nanocomposites having improved properties by using organic modified clay and pristine clay - Google Patents

Abstract

The present invention relates to a method for producing an organic clay used in a polymer nanocomposite, an organic clay prepared by the above method, and a polyester nanocomposite prepared using the organic clay and an inorganic clay. More specifically, in the preparation of polyester nanocomposites by appropriately selecting the nano clay mineral used in the polymer nanocomposite according to the polymer resin and organicizing the layered silicate, the nano clay mineral, the polyester resin suitability of the clay mineral The present invention relates to a method for producing a polyester nanocomposite having improved dispersibility, transparency, and gas barrier property by containing nanoclay minerals and organically treated layered silicates appropriately selected above by increasing the physical properties and in-situ polymerization.

Description

The organic modification method of clay minerals for polyesters and the preparation method of polyester nanocomposites having improved properties by containing organically treated clay minerals and inorganic clays using organic modified clay and pristine clay}

The present invention relates to a method for producing an organic clay used in a polymer nanocomposite, an organic clay prepared by the above method, and a polyester nanocomposite prepared using the organic clay and an inorganic clay. More specifically, in the preparation of polyester nanocomposites by appropriately selecting the nano clay mineral used in the polymer nanocomposite according to the polymer resin and organicizing the layered silicate, the nano clay mineral, the polyester resin suitability of the clay mineral The present invention relates to a method for producing a polyester nanocomposite having improved dispersibility, transparency, and gas barrier property by containing nanoclay minerals and organically treated layered silicates appropriately selected above by increasing the physical properties and in-situ polymerization.

The manufacturing technology of the polymer nanocomposite is a technology that can improve the properties of existing polymers by adding clay minerals of very fine size with an additive size of 1 to 100 nm, unlike the production of conventional composite materials. Compared to the amount of additives used in existing composite materials, the use of nanocomposite technology can reduce the amount to less than 5% and has the advantage of improving physical properties. Typically, the clay mineral used in the polymer nanocomposite is a layered silicate having a large surface area (about 750 m 2 / g) and a large aspect ratio of 50 or more, which has a thickness of about 1 nm. Due to this property, when the layered silicate is dispersed in the polymer matrix, even a small amount of addition may improve the physical properties of the polymer, that is, mechanical properties, heat resistance, and gas barrier properties. Toyota CRDL Group of Japan has developed nylon nanocomposites using the above advantages. Based on this, many research groups have developed and developed automobile timing belt covers using nylon-6 nanocomposites. The commercialization of polymer nanocomposites such as belt cover), TPO nanocomposite's automobile exterior materials applied by General Motors (GM), and nanocomposite films for food packaging with increased gas barrier properties are continuously being developed.

However, the method for producing polymer nanocomposites using clay minerals is quite difficult, and since the hydrophilic nature of the layered silicates used as clay minerals is inherently hydrophilic, it is generally not suitable for hydrophobic polymers and thus the dispersibility is improved. Hard to reach the properties. Therefore, in order to impart hydrophobicity to the layered silicate, it is necessary to substitute organic material and improve compatibility with the polymer. In particular, the structure of the organic material compatible with the polymer to be applied should be predicted and synthesized, and the substitution of the organic material in the layered silicate is the most important technology in manufacturing the polymer nanocomposite.

The most successful polymer nanocomposite developed so far is a nylon-based nanocomposite. Briefly, the technique is described first by replacing alkylammonium acid, which can react with a nylon monomer, between the layered silicate layers, The disperse layered silicate is dispersed and then polymerized to have a mechanism for inducing peeling of the layered silicate. The alkylammonium acid intercalated between the silicate layers reacts with the nylon monomers to polymerize into polymer chains, which causes the layered silicate layers to expand, eventually exfoliating morphology and expressing their performance as nanocomposites. Done.

In the case of polyester nanocomposites, basic research has been attempted, but few examples have sufficient peeling structures or commercialized products such as nylon nanocomposites. The reason for this is that the organic substituted clays developed to date cause a side reaction during the polymerization process due to lack of compatibility with polyester and high temperature stability, and cause various problems such as deterioration of the polymerization degree of the nanocomposite due to decomposition. Various attempts have been made to solve this problem, and techniques for preparing polyester nanocomposites have been introduced.

For example, US Pat. Nos. 5,876,812 and 5,972,448 describe methods and properties of nanocomposite polymer containers. In-situ polymerization method, solution method, and melting method were introduced as a method of preparing a polyester nanocomposite, and a method of manufacturing a low oxygen permeability container was described. However, there is no detailed embodiment of the polyester nanocomposite manufacturing method, there is a side reaction and a decrease in viscosity occurs in the production of the polyester nanocomposite by the solution method and the melting method is difficult to proceed to the normal molding process. In addition, in the in-situ polymerization method, there is no specific reference to the type and content of the dispersant of the nanoclay, and the molten monomer is not accurately described. In addition, in the case of polyester polymerization, the structure of the organic agent inside the nanoclay is maintained due to a high temperature of 300 ° C., and decomposition is easily performed when the structure is not capable of reacting with the polyester polymer. It is known to cause problems such as viscosity decrease, discoloration and surface defects.

Meanwhile, US Pat. Nos. 6,071,988, 6,084,019, 6,162,857, 6,359,052 B1, and 6,387,996 B1 describe methods for producing polyester nanocomposites after organizing layered silicates. Specifically, a method for producing nanocomposites having improved dispersibility and oxygen barrier property by extending the interlayer distance of layered silicates and using polyester polymerization using polyalkoxylated ammonium compounds and other organic agents. Is disclosed. However, the polyalkoxylated ammonium-based organic clays cause esterification reaction during polyester polymerization, i.e., reduced polyester conversion when added early in the reaction, so that they are added later in the reaction, after the production of oligomeric low molecular polyester. There is a limit to this, and also discoloration and poor transparency that occur during the high temperature step of the polymerization reaction may appear. In addition, there is a problem that a factor causing an additional process occurs when applied to the existing polyester polymerization process due to the limitation of the input position during the manufacturing process.

On the other hand, U.S. Patent No. 6,562,891 B1 discloses that the input position in the organic treatment of the layered silicate during the preparation of the polyester nanocomposite has been since the production of oligomer-type low molecular polyester (bis-2-hydroxyethyl ester, BHET) Although the technique is described, the problem described above is still not solved.

 Therefore, the present inventors have studied to solve the above problems, can be effectively inserted into the layered silicate and do not cause a reduction in the conversion rate in the ester reaction of the polyester can be added at the beginning of the reaction, high temperature polyester polymerization When preparing a polyester-compatible organic agent that does not cause side reactions due to decomposition at temperature and using the same to organicize the nanosilicate layered silicate, the polyester nanocomposite prepared using the organicated layered silicate is The present invention has been found to be excellent in acidity, transparency and gas barrier properties.

Accordingly, it is an object of the present invention to provide an organic agent for organic substitution of nanoclays.

Another object of the present invention is to provide an organic nanoclay having excellent polyester suitability prepared using the organic agent.

In addition, another object of the present invention to provide a polyester nanocomposite prepared using the organic nanoclay.

In addition, another object of the present invention is to provide a method for producing the polyester nanocomposite.

In order to achieve the above object, the polyester nanocomposite of the present invention is (1) a layered silicate suitable for the polyester nanocomposite, the basic interlayer distance is in the range of 9 ~ 13Å, cation exchange capacity is 50 ~ 300meq / 100g, average particle diameter Selecting a layered silicate having a thickness of 50 µm or less; (2) preparing an organic agent for organic substitution of the layered silicate selected in step (1); (3) preparing organic clay by inserting the organic agent synthesized in step (2) into the layered silicate; And (4) preparing a polyester nanocomposite by In-Situ polymerization using the organic clay prepared in step (3).

The organic agent of the present invention is prepared by reacting a tertiary amine compound with a compound having a carboxylic acid group to synthesize an oligomer containing an ester group.

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

(1) selecting a layered silicate suitable for the polyester nanocomposite;

The above step is to select the inorganic clay, the inorganic clay layer silicate used in the present invention can be polymer inserted, the basic interlayer distance of the layered silicate range of 9 ~ 13Å, cation exchange capacity is 50 ~ 300meq / A silicate having a value of 100 g, preferably 90 to 130 meq / 100 g is used. In addition, the macroscopic average particle diameter of the layered silicate is a layered silicate having an average particle diameter of 50 μm or less, preferably 25 μm or less, more preferably 10 μm or less.

Specific examples of the layered silicate that satisfies the above conditions include sodium montmorillonite, sodium hectorite, bentonite, saponite, margotite, etc., and may be used singly or in combination according to the user's conditions.

(2) organic agents for organic substitution of layered silicates;

The organic agent constituting the main part of the present invention is a compound having excellent compatibility since it may have a reactivity with a polyester matrix in a polymer nanocomposite, and is basically composed of a compound obtained through an ester reaction.

Compounds used as organic agents in the present invention are largely divided into two types. First, tertiary amine-based materials capable of substitution reaction with layered silicates, having at least one hydroxyl group, preferably at least two hydroxyl groups at the terminal, having an acid group at the terminal. Tertiary amine-based materials capable of ester reaction with the compound are used. The tertiary amine-based material which can prepare the organic agent used in the present invention is shown in the following formula (1).

(In the above formula, N is nitrogen, and R ₁ , R ₂ , and R ₃ are each commonly composed of an alkyl group having 1 to 8 carbon atoms, which may be used independently or in duplicate. Means.)

Secondly, another compound required to prepare the organic agent used in the present invention is one or more carboxylic acid groups, preferably at the end to enable the ester reaction with the hydroxyl group of Formula 1 Compounds having two or more carboxylic acid groups are used. The compound is shown in the following formula (2).

(Wherein R is an alkyl group having 1 to 10 carbon atoms and an aromatic compound, at least one of A ₁ , A ₂ , A ₃ , and A ₄ is a carboxylic acid, and the rest is a hydroxyl group or hydrogen. )

In order to prepare an organic agent used in the present invention, the oligomer including the ester group is synthesized by reacting the compound of Formula 1 and Formula 2. Synthesis method of the oligomer is similar to the conventional esterification reaction, the conditions may vary depending on the type of the compound of Formula 1 and Formula 2.

The esterification reaction may be carried out in a composition of 1 mol of the compound of Formula 1 and 1 mol of the compound of Formula 2 or more, preferably 2 mol of the compound of Formula 2, and then gradually heated in a nitrogen atmosphere, thereby reducing water or alcohol due to esterification. When it starts to form, it proceeds until the reaction is completed while maintaining the temperature to synthesize oligomers including ester groups.

Since the oligomer synthesized above has a tertiary amine in the structure, it can be easily converted to ammonium salt by ammonium salt (HCl), and has the characteristic of being inserted into the layered silicate and substituted by the ammonium salt. Therefore, the organic agent used in the present invention can complete the preparation of the organic agent by converting the oligomer synthesized in the aqueous solution to the ammonium salt by HCl.

(3) preparing organic clay by inserting the organic agent synthesized in step (2) into the layered silicate;

First, in order to organicize the layered silicate, the layered silicate is added to deionized water and stirred to prepare a dispersion. The dispersion is prepared by adding 1 to 10 parts by weight of the layered silicate, preferably 1 to 5 parts by weight, based on 100 parts by weight of deionized water, and is prepared by raising the temperature for uniform dispersion of the layered silicate. At this time, a temperature rising temperature is 90 degrees C or less, Preferably it processes on 50-85 degreeC conditions.

Next, to the dispersion solution is added the aqueous solution of the organic agent of step (2), the organic agent aqueous solution is prepared by adding 5 to 20 parts by weight based on 100 parts by weight of deionized water, and added to the cation exchange capacity of the layered silicate The agent weight and HCl treatment amount can be adjusted. When the aqueous solution of the organic agent prepared in step (2) is added slowly, the concentration of the organic agent is rapidly increased as the organic agent is inserted into the layered silicate. The mixed solution is filtered and washed several times, and then completely dried by vacuum drying or freeze drying to prepare organic clay in powder form.

(4) preparing a polyester nanocomposite by In-Situ polymerization using the organic clay prepared in step (3);

The organic clay prepared in step (3) can be applied irrespective of the injection position in a conventional polyester polymerization method.

The method of preparing the polyester nanocomposite by adding the organic agent and the organic clay prepared in the above (2) and (3) will be described in more detail.

First, diacid compounds such as terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl naphthalate, naphthalene dicarboxylic acid and naphthalenedicarboxylic acid dimethyl ester, which are monomers of polyester, and ethylene glycol and diethylene glycol Diol compound, such as triethylene glycol, 1,4-butanediol, trimethylene glycol, 1,4-cyclohexane dimethanol, in an amount of diol, that is, 1.1 to 2 times in a molar ratio, and mixed in a slurry To prepare. In this case, the production conditions are based on the examples generally performed in polyester polymerization, and may be selected by changing monomers and conditions as necessary. In addition, the organic clay prepared in step (3) is 0.1 to 10% by weight, preferably 0.3 to 5% by weight, more preferably 0.5 to 3% by weight compared to the expected production amount of polyester diol before slurry preparation Slowly adding to the compound while stirring to prepare a uniformly dispersed diol-organic clay solution. At this time, the stirring time is maintained for 30 minutes to 6 hours, preferably 1 hour to 3 hours to prepare a uniform solution.

Next, when a diol-organic clay solution is prepared, a uniform slurry-like mixed solution is prepared while slowly adding a predetermined number of moles of diacid compounds, terephthalic acid or dimethyl terephthalate. At this time, in order to manufacture the copolymerized polyester nanocomposite, heterologous monomers such as isophthalic acid may be appropriately used. Next, a phosphorus (P) -based heat stabilizer and a polyester polymerization catalyst are added to the uniformly prepared slurry, and in-situ polymerization is started. Herein, the polyester polymerization catalyst is not particularly limited, and a catalyst applicable to polyester polymerization such as antimony, germanium, and titanium may be used without limitation.

In the polymerization of the polyester nanocomposite by adding the organic clay prepared in the present invention, the polymerization conditions are not limited, and the reaction may proceed similarly to conventional conditions. First, proceed with the esterification reaction at a reaction temperature of 240 ~ 260 ℃, and after the esterification reaction is carried out a condensation polymerization process in the range of about 280 ~ 290 ℃ under reduced pressure to the value of the ultimate viscosity (IV) of about 0.6 dl / g Eggplant can produce a polyester nanocomposite. At this time, side reactions and reaction delays due to the addition of the organic clay do not occur.

The polyester nanocomposite prepared in the above step increases the compatibility with the polyester, including the organic clay using the organizing agent, which is the main component of the present invention, and does not cause side reactions at any position in the polymerization process. It can be added to the slurry of the monomer mixture before the reaction to simplify the process and to produce a polyester nanocomposite having excellent dispersibility even after the polymerization. In addition, the layered silicate is uniformly dispersed in the polyester, thereby producing a polyester nanocomposite having excellent transparency and improved gas barrier properties.

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited only to these examples.

[Production Example 1]

In order to organicize the layered silicate, citric acid was used as a compound containing N-methyl diethanol amine and a carboxylic acid group as a tertiary amine compound. 325 g of citric acid was added to a four neck reactor, and the mixture was gradually heated while stirring in a nitrogen atmosphere to completely melt. Next, while maintaining the temperature of 150 ℃, N-methyl diethanol amine 100g was slowly dropped through the dropping funnel, and after the addition was increased to increase the temperature to proceed with the esterification of the two compounds at a temperature of 200 ℃ or less. After the completion of the dehydration due to esterification, the reaction was terminated and cooled to room temperature, and the reactants were completely dissolved by adding 1000 ml of distilled water.

Meanwhile, 20 g of sodium montmorillonite (Cloisite Na; Southern Clay Products; CEC = 92.6 meq / 100 g) was added to 1600 ml of deionized water as a layered silicate, and then heated and stirred to prepare a uniform dispersion.

Next, in consideration of the cation exchange capacity of the layered silicate, the aqueous solution of N-methyl diethanol amine and citric acid prepared in advance was treated with HCl in a slight excess. Stirring was performed for 10 to 60 minutes to sufficiently exchange the prepared compound to prepare an aqueous solution containing the organic substituted layered silicate. Next, the aqueous solution was repeated two to three times of filtration and washing, and after confirming the removal of the residual compound with AgNO ₃ solution to prepare an organic clay in the form of powder through vacuum drying or freeze drying.

[Production Example 2]

As a compound containing a carboxylic acid group in the preparation of a layered silicate organication, 165 g of adipic acid is added, followed by heating while suppressing sublimation to prepare adipic acid in a molten state. And to prepare an organic clay in the form of powder in the same manner as in Preparation Example 1.

Example 1 Preparation of Polyester Nanocomposite

The organic clay prepared in Preparation Example 1 was used to prepare the polyester nanocomposite. First, 0.5 g of a thermal stabilizer triethyl phosphate and 0.5 g of cobalt acetate are added to a 1000 g of ethylene glycol at room temperature, and cobalt acetate is added thereto, followed by stirring, while slowly adding 15 g of the organic clay prepared in Preparation Example 1. Continuous stirring was performed to ensure a uniform solution. Next, when a uniform solution was prepared, slowly adding 2600 g of terephthalic acid to increase the stirring speed to prepare a mixed solution in a slurry state. 1.8 g of Sb (OAc) _{3 as a} catalyst was dissolved in 200 g of ethylene glycol at elevated temperature to completely dissolve it, and then charged into the slurry mixture. Next, the mixed solution was introduced into a 7L ester reactor, and then gradually heated up to proceed with the esterification reaction at 240 to 260 ° C. and 1 kg / cm 2 pressure, and when the effluent from the ester reaction was completely removed, the mixture was transferred to the 5 L condensation polymerization reactor. . Thereafter, the temperature is gradually increased to 290 ° C, and condensation polymerization is carried out in a reduced pressure environment of 1 torr or less. When the torque value corresponding to the ultimate viscosity (IV) of 0.6 mW / g is reached, the polymerization is terminated and discharged to obtain a water bath and pelletizer. The polyester nanocomposite of pellet form (2 mm width x 3 mm length) was prepared.

Example 2 Preparation of Polyester Nanocomposite

A polyester nanocomposite in pellet form was prepared in the same manner as in Example 1 except that the organic clay prepared in Preparation Example 2 was used to prepare the polyester nanocomposite.

Example 3 Preparation of Polyester Nanocomposite

A polyester nanocomposite in pellet form was prepared in the same manner as in Example 1, except that 30 g of the organic clay prepared in Preparation Example 2 was added to prepare the polyester nanocomposite.

Example 4 Preparation of Polyester Nanocomposite Using Sodium Montmorillonite with an Average Particle Size of 10 μm

To prepare polyester nanocomposites using unorganized sodium montmorillonite, 30 g of Cloisite Na (Southern Clay Products; CEC = 92.6 meq / 100 g) with an average particle diameter in the range of 10 μm was used as a thermal stabilizer, triethyl phosphate. And cobalt acetate (Cobalt acetate) was added to 1000g of ethylene glycol at 80 ℃ formulated while stirring to prepare a uniform dispersion. Next, while slowly adding 2600 g of terephthalic acid, the stirring speed was increased to prepare a mixed liquid in a slurry state.

On the other hand, 1.8 g of Sb (OAc) ₃ as a catalyst was dissolved in 200 g of ethylene glycol at elevated temperature and completely dissolved therein, and then charged into the slurry mixture prepared above. Next, the mixed solution was introduced into a 7L ester reactor, and then gradually heated up to proceed with the esterification reaction at 240 to 260 ° C. and 1 kg / cm 2 pressure, and when the effluent from the ester reaction was completely removed, the mixture was transferred to the 5 L condensation polymerization reactor. . After that, the temperature is gradually increased to 290 ° C, and condensation polymerization is carried out in a reduced pressure environment of 1 torr or less. When the torque value corresponding to the ultimate viscosity (IV) of 0.6 mW / g is reached, the polymerization is terminated and discharged. The polyester nanocomposite of pellet form (2 mm width x 3 mm length) was prepared.

Comparative Example 1 Preparation of Polyester Nanocomposite Using Sodium Montmorillonite with an Average Particle Size of 100 μm

To prepare polyester nanocomposites using unorganized sodium montmorillonite, 30 g of Kunipia-F (Kunimine Co., CEC = 119 meq / 100 g) having an average particle diameter in the range of 100 μm was converted to triethyl phosphate as a thermal stabilizer. ) And cobalt acetate as a colorant were slowly added to 1000 g of ethylene glycol at 80 ° C. and stirred to prepare a uniform dispersion. Then, a polyester nanocomposite of pellet form (2 mm width x 3 mm length) was prepared in the same manner as in Example 4.

Comparative Example 2 Preparation of Polyester Nanocomposite Using Organic Montmorillonite Products

Polyester nanocomposites were prepared using 30 g of Cloisite 30A (Southern Clay Products; CEC = 90 meq / 100 g) substituted with quaternary ammonium salts in the organicized montmorillonite product. The preparation method was carried out under the same conditions as in Comparative Example 1 to prepare a polyester nanocomposite of pellet form (2 mm width x 3 mm length).

Comparative Example 3 Preparation of Polyester Nanocomposite Using Organic Montmorillonite Products

Polyester nanocomposites were prepared using 15 g of Nanofil 15 (Sd-Chemie AG) substituted with distearyldimethylammonium chloride in the organicized montmorillonite product. The preparation method was carried out under the same conditions as in Comparative Example 1 to prepare a polyester nanocomposite of pellet form (2 mm width x 3 mm length).

Comparative Example 4 Preparation of Polyester Nanocomposite Using Organic Magnesite

In order to prepare a polyester nanocomposite using mardecite organicized with dodecylamine, 30 g of organic margarite was added to proceed in the same conditions as in Comparative Example 1 to form a pellet (2 mm width x 3 mm length) polyester nanocomposite was prepared.

[Test Example 1]

In order to observe the properties of the organic layered silicate prepared in Preparation Examples 1 and 2 of the present invention, using an X-ray diffractometer (Rigaku X-ray generator) in the 2 theta (2θ) range 1.2 ~ 10 ° scan conditions The layered silicate interlayer distances were measured, and for comparison, X-ray diffraction analysis of sodium montmorillonite (Cloisite Na), which is a layered silicate before organicization, was performed, and is shown in FIG. 1. In Figure 1 (a) is sodium montmorillonite, (b) is an organic layered silicate prepared in Preparation Example 1, (c) is an X-ray diffraction result of the organic layered silicate prepared in Preparation Example 2.

As can be seen in Figure 1, it can be observed that the interlayer distance of the organic layered silicate of Preparation Examples 1 to 2 moved to the incineration than before the organicization, when converted to the actual interlayer distance before the organicization It can be seen that the distance of 12 층 was extended from 14.4 ~ 14.6Å. Therefore, it is to confirm that the organic compound prepared in Preparation Examples 1 and 2 of the present invention was successfully inserted into the sodium montmorillonite interlayer.

[Test Example 2]

In order to compare the polymerization results for the polyester nanocomposites prepared in Examples 1 to 3 and the polyester nanocomposites prepared in Comparative Examples 2 to 4, IV for each sample was measured by solution viscosity measurement, and the appearance and Surface properties were measured by optical microscope and image analyzer for the pellets. The results are shown in Table 1 and FIGS. 2 to 6. 2 shows Examples 1, 3 shows Example 2, FIG. 4 shows Comparative Example 2, FIG. 5 shows Comparative Example 3, and FIG. 6 shows polyester nanocomposite pellets prepared by Comparative Example 4.

Sample Clay content (% by weight) I.V. (㎗ / g) Appearance and characteristics Example 1 0.5 0.6 Transparency and clay dispersion Example 2 0.5 0.6 Transparency and clay dispersion Example 3 1.0 0.6 Transparency and clay dispersion Comparative Example 2 1.0 0.3 Severe discoloration, poor dispersion, low polymerization Comparative Example 3 0.5 0.3 Severe discoloration, poor dispersion, low polymerization Comparative Example 4 1.0 0.6 Discoloration and clay dispersion

As confirmed in Table 1, the polyester nanocomposite prepared in Examples 1 to 3 is I.V. 0.6 ㎗ / g was shown to reach a normal degree of polymerization, the appearance was also good transparency and dispersibility. On the other hand, polyester nanocomposites prepared in Comparative Examples 2 and 3 are I.V. 0.3 ㎗ / g, and the esterification was delayed and the torque did not rise properly during the polycondensation reaction. As a result, normal polymerization was impossible. In addition, it was found that the appearance of the prepared pellets completely discolored to cause severe side reactions, and the transparency and dispersibility were greatly reduced. On the other hand, in the case of the polyester nanocomposite prepared by the method of Comparative Example 4 I.V. 0.6 ㎗ / g was shown to have a normal degree of polymerization, but the appearance of the prepared pellet was discolored and the transparency and dispersibility were reduced.

From the above results, the organic clay through the nanoclay organic treatment method of the present invention does not cause problems such as reduced polymerization degree, discoloration, and the like in the production of polyester nanocomposites compared to the existing organic clay, and has excellent dispersibility, transparency, and performance. It can be seen that improved polyester nanocomposites can be prepared.

[Test Example 3]

In order to compare the difference between the polyester nanocomposite prepared by the method of Example 4 and Comparative Example 1, the appearance and surface properties were observed using an optical microscope and an image analyzer. The results are shown in Figures 7 to 8 below, Figure 7 is a microscope image of the polyester nanocomposite pellet of Example 4, Figure 8 is an image of the polyester nanocomposite pellet prepared by the method of Comparative Example 1.

As can be seen in Figures 7 to 8, it can be seen that the polyester nanocomposite of Example 4 exhibits excellent characteristics in transparency and appearance, transparency of the polyester nanocomposite prepared by Comparative Example 1 It was confirmed that the surface was very nonuniform and agglomerated layered silicate particles were observed. From this, in order to apply to the polyester nanocomposite, the inorganic clay should be selected in consideration of the average particle diameter, it was confirmed that the normal polyester nanocomposite can be prepared using this.

[Test Example 4]

Improvements expected from the successful manufacture of polyester nanocomposites include mechanical properties, heat resistance and flame retardancy, but the most important expected properties are improvement of gas barrier properties. Polyester containers, ie, PET containers, are widely used as beverage and food containers, but their application is suspended for beverages and foods sensitive to specific gas permeation. In particular, oxygen permeability is used as a measure of gas barrier properties as a representative factor that can lead to corruption and deterioration of beverages.

Therefore, the solid phase polymerization was applied to the polyester nanocomposites prepared in Examples 3 and 4 to test the oxygen permeability of the polyester nanocomposites prepared in the present invention to increase the degree of polymerization to an ultimate viscosity of 0.8 dl / g. At this time, the solid phase polymerization process using a 10L tumbler reactor and the polymerization conditions were preliminarily subjected to 10 to 20 hours in the reaction temperature range of 200 ~ 230 ℃ and reduced pressure of 0.1torr or less to increase the degree of polymerization. Polyester nanocomposites with increased degree of polymerization through the solid-phase polymerization process are referred to as Example 3 ^* , Example 4 ^* , and HOPET TB-180 (Honam), which is used as a polyester resin for beverage containers for comparison with existing polyester resins. KK Chemical Co., Ltd., intrinsic viscosity 0.8 ㎗ / g). For the oxygen permeability test, Example 3 ^* and Example 4 ^* SHEET molding was performed on the existing polyester resin TB-180 having the same polymerization degree as the polyester nanocomposite, and the temperature gradient of the SHEET molding extruder barrel was 270-290 ° C. The average thickness after sheet molding was 230 μm. Oxygen permeability test was measured using a MOCON OXTRAN 2/21 oxygen permeability meter and the results are shown in Table 2 below.

Sample Clay content (% by weight) I.V. (㎗ / g) Oxygen permeability SHEET OTR ^* (㎜ · ㏄ / ㎡ · day) Conventional polyester 0 0.8 6.48 Example 3 ^* One 0.8 3.14 Example 4 ^* One 0.8 3.41 OTR ^* : Oxygen Transmission Rate

As can be seen in Table 2, the oxygen permeability value of the polyester nanocomposite resin prepared by Example 3 ^* and Example 4 ^* of the present invention compared to the oxygen permeability value of the existing polyester resin is 1.9 ~ 2.5 times It was found that the level was lowered. Therefore, it was confirmed that the polyester nanocomposite resin of the present invention had improved oxygen barrier property than the conventional polyester resin.

As described above, the organically treated layered silicate prepared in the present invention does not cause side reactions during the preparation of the polyester nanocomposite, and can produce a polyester nanocomposite having a normal degree of polymerization by an in-situ polymerization method. The polyester nanocomposite produced is characterized by improved dispersibility, transparency, and gas barrier properties.

1 is an X-ray diffraction analysis of the organic layered silicate and sodium montmorillonite prepared in Preparation Example 1 and Preparation Example 2.

Figure 2 is a micrograph of the polyester nanocomposite prepared by the method of Example 1.

Figure 3 is a micrograph of the polyester nanocomposite prepared by the method of Example 2.

Figure 4 is a micrograph of the polyester nanocomposite prepared by the method of Comparative Example 2.

5 is a micrograph of the polyester nanocomposite prepared by the method of Comparative Example 3.

Figure 6 is a micrograph of the polyester nanocomposite prepared by the method of Comparative Example 4.

7 is a micrograph of the polyester nanocomposite prepared by the method of Example 4.

8 is a micrograph of the polyester nanocomposite prepared by the method of Comparative Example 1.

Claims (10)

In the production of polyester nanocomposites, (1) selecting a layered silicate having a basic interlayer distance of 9 to 13 kPa, a cation exchange capacity of 50 to 300 meq / 100 g, and an average particle diameter of 50 µm or less as a layered silicate suitable for the polyester nanocomposite; (2) preparing an organic agent for organic substitution of the layered silicate selected in step (1); (3) preparing organic clay by inserting the organic agent synthesized in step (2) into the layered silicate; And (4) preparing a polyester nanocomposite by In-Situ polymerization using the organic clay prepared in step (3); Method for producing a polyester nanocomposite comprising a. The method of claim 1, wherein the layered silicate is at least one member selected from the group consisting of sodium montmorillonite, sodium hectorite, bentonite, saponite, and margadite. According to claim 1, wherein the organic agent is a tertiary amine (tertiary amine) -based material represented by the following formula (1), characterized in that the poly is produced using a material containing one or more hydroxyl (hydroxyl) at the end Method for producing ester nanocomposite. [Formula 1] (In the above formula, N is nitrogen, and R ₁ , R ₂ , and R ₃ are each commonly composed of an alkyl group having 1 to 8 carbon atoms, which may be used independently or in duplicate. Means.) The method of claim 1, wherein the organic agent is a material represented by the following formula (2) is prepared using a compound having at least one carboxylic acid (carboxylic acid) terminal at the end to enable the ester reaction with the hydroxyl group of the compound of Formula 1 Method for producing a polyester nanocomposite, characterized in that. [Formula 2] (Wherein R is an alkyl group having 1 to 10 carbon atoms and an aromatic compound, at least one of A ₁ , A ₂ , A ₃ , and A ₄ is a carboxylic acid, and the rest is a hydroxyl group or hydrogen. ) When the compounds of the formula (1) and the formula (2) with respect to the compound of the formula (1) is slowly heated in a nitrogen atmosphere in a molar ratio of 1: 1 or more in a molar ratio, the temperature is gradually increased when water or alcohol starts to be produced by the esterification reaction. The process for producing an organic agent, characterized in that to proceed until the reaction is terminated while maintaining an organic compound of the oligomer form including an ester group. 1-10 parts by weight of the layered silicate was added to 100 parts by weight of deionized water to prepare a dispersion, and then an aqueous solution of an organic agent prepared by adding 5 to 20 parts by weight of the organic agent of claim 5 to 100 parts by weight of deionized water was added to the dispersion. A method for producing organic clay, characterized in that to produce an organic clay in addition to. The organic clay according to claim 6 was slowly added to a diol compound as a polyester monomer while stirring to prepare a uniformly dispersed diol-organic clay solution, and then a diacid compound as the monomer of polyester and the diol. Polyester nanocomposite, characterized in that the (diol) -organic clay solution is mixed to prepare a mixed solution on the slurry prepared by In-situ polymerization. 8. The polyester nanocomposite of claim 7, wherein the organic clay is contained in an amount of 0.1 to 10% by weight based on the expected polyester production. The diacid compound according to claim 7, wherein the diacid compound is at least one selected from the group consisting of terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethylnaphthalate, naphthalene dicarboxylic acid and naphthalenedicarboxylic acid dimethyl ester. Polyester nanocomposite characterized in that. The diol compound of claim 7, wherein the diol compound is at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, trimethylene glycol, 1,4-cyclohexane dimethanol Polyester nanocomposite characterized in that.