KR100519560B1 - PET/clay Nanocomposite and Process Preparing the Same - Google Patents

Abstract

The present invention relates to a method for producing PET / clay nanocomposites having excellent gas barrier properties and mechanical properties without deteriorating physical properties such as impact resistance, toughness and transparency, and more specifically, to PET / clay nanocomposites prepared by the method. Manufacturing Na-MMT (Montmorillonite) into organic clay using organic agent designed and synthesized to improve thermal stability, and then manufacturing it into PET / clay nanocomposite by compounding method by melt-mixing with PET polymer resin A method and a PET / clay nanocomposite produced by the method.

Description

Polyester / clay nanocomposite and manufacturing method thereof {PET / clay Nanocomposite and Process Preparing the Same}

The present invention relates to a method for producing PET / clay nanocomposites having excellent gas barrier properties and mechanical properties without deteriorating physical properties such as impact resistance, toughness and transparency, and more specifically, to PET / clay nanocomposites prepared by the method. Manufacturing Na-MMT (Montmorillonite) into organic clay using organic agent designed and synthesized to improve thermal stability, and then manufacturing it into PET / clay nanocomposite by compounding method by melt-mixing with PET polymer resin A method and a PET / clay nanocomposite produced by the method.

Poly (ethylene terephthalate) (PET), a representative polyester, was first industrialized by ICI for textiles in 1949. It grew into one of the three major synthetic fibers with nylon and acrylic fibers. It has grown rapidly on the basis of excellent physical properties such as high heat resistance, transparency, gas barrier property, and stretchability, processing characteristics and price competitiveness. In particular, while the market has entered the maturity stage, with its unique position in the beverage bottle and magnetic tape films, production continues to increase due to efforts for quality improvement.

In general, PET is synthesized by condensation polymerization of terephthalic acid and ethylene glycol. First, it has excellent adhesion and coating properties to metal materials and textile products, and second, excellent weather resistance, thermal stability, insulation, and excellent appearance. Harmless point, fourth, it is excellent in dyeing, anti-pilling, etc., and has the same mechanical properties as conventional fibers. Despite these various advantages, efforts have been made to achieve better performance as mentioned above. PET, which has excellent heat resistance, gas barrier properties, and other mechanical properties at the level of engineering plastics by peeling and dispersing clay such as MTT in the resin One effort is to make clay nanocomposites.

The manufacture of polymer resin / clay nanocomposites is not a method of improving the physical properties by adding a micron (10 ^-6 m) reinforcing agent, but by dispersing the particle size of the inorganic filler / reinforcing agent to the nanometer scale. Its basic goal is to overcome the shortcomings of the system, and it is one of the key technologies that is expected to bring a big change in the next generation composite market in a very advantageous way in terms of cost performance.

In 1987, researchers in Japan and Japan have reported that peeling phenomenon of increasing the distance between layers by 10 nm by inserting nylon monomer between silicate layers by means of appropriate methods and polymerizing them interlayer has been studied in the United States and Japan. There was a problem that can be used only when possible and that existing industrial equipment cannot be used as it is.

In 1993, Japan's Yano et al prepared polyimide / clay nanocomposites in such a way that solvents penetrated between the silicate layers to disperse the silicate layer and maintain this dispersion by immersing the MMT treated with the organic agent in the polymer solution. There is a problem that a large amount of solvent is used and a separate solvent removal process is required, and the polymer is simply inserted into the organic MMT layer or the interlayer distance is narrowed again during the solvent drying process.

An object of the present invention is to provide a technique for producing a PET / clay nanocomposite dispersed and peeled silicate layer forming the MMT in a PET resin using a novel organic agent with excellent thermal stability in order to solve the above problems. .

In order to achieve the above object, the present invention comprises 0.1 to 50% by weight of the organic agent of Figure 1, characterized in that to produce a release-type PET / clay nanocomposite excellent dynamic mechanical properties.

In addition, an organic clay is prepared by adding the organic agent of FIG. 1 to clay, and a method of preparing a peelable PET / clay nanocomposite having excellent dynamic mechanical properties prepared by dispersing the organic clay in a PET resin by a compounding method. It is done.

In addition, the clay is preferably used Na-MMT.

In addition, the organic clay is preferably prepared by mixing Na-MMT and the organic agent shown in Figure 1 in a water / THF mixed solvent.

In addition, the content of the organic clay in the PET resin is preferably 0.1 to 50% by weight to prepare a nanocomposite.

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

Clay is a mineral that constitutes the earth's surface and is classified as a layered compound because its structure is basically based on the layered structure of silicate layers. There are various types such as montmorillonite (hereinafter 'MMT'), saponite, hectorite, etc., but in the present invention, Na-MMT was used.

Among the most commonly used clays for the production of polymer / clay nanocomposites, MMT is a layered compound commonly found in nature and is a mica-like layered silicate mineral belonging to the smectite group. Due to the cations such as Na ⁺ and Ca ²⁺ present between the silicate layers, inorganic compounds such as swelling property, various reactivity with organic compounds, ion exchange ability, etc. are rare. MMT is generally referred to as Na-MMT because most of the ion exchangeable cations present between the layers of MMT are Na ⁺ .

In order to facilitate intercalation of organics, an organic agent should be used to increase the lipophilic properties of Na-MMT. In general, clay is very difficult to exfoliate and disperse in polymer resin due to strong van der Waals attraction between the layers of silicate and narrow interlayer distance.The pretreatment process of inserting low molecular weight lipophilic organic agent into the silicate layer through ion exchange reaction Peeling and dispersion into the polymer resin can be induced through. Clay that has undergone such pretreatment is called organic clay.

In the present invention, a new organic agent having compatibility with PET resin and excellent thermal stability was designed and synthesized as shown in FIG. 1, and the organic clay was prepared by ion exchange reaction with Na-MMT. The thermal stability of the organic agent is required because the high melting point of the PET resin (260 ℃) in the production of PET / clay nanocomposites is inevitable high temperature melt mixing in the production of PET / clay nanocomposites.

In the organic agent of the present invention, phosphonium ions are introduced as a cationic head group to increase thermal stability, instead of conventional ammonium ions, and a tail group is used to increase compatibility between the organic agent and PET resin. As a basic skeleton, the repeating unit of the phenoxy resin was designed.

The organic agent designed as described above was synthesized as follows.

2,2-bis (4-glycidyloxyphenyl) propane is placed in a vessel together with a solvent such as purified acetonitrile or butyronitrile and stirred while flowing nitrogen gas to form a uniform solution. At the same time, 0.1 to 40 times 2-bromoethanol was added to a separate container based on the number of moles of the catalyst such as magnesium perchlorate or lithium perchlorate and 2,2-bis (4-glycidyloxyphenyl) propane. Stir while pouring. Slowly raise the temperature of the vessel containing magnesium perchlorate and 2-bromoethanol to 80 ° C., and prepare a 2,2-bis (4-glycidyloxyphenyl) propane / acetonitrile solution in a small amount while flowing nitrogen gas. Slowly put in. The reaction proceeds at 80 ° C. for several hours. The reaction product is extracted with diethyl ether, washed several times with water, the diethyl ether layer is separated, dried over anhydrous magnesium sulfate, and diethyl ether and unreacted substance are removed by an evaporator to give a dark yellow organic agent intermediate.

0.1 to 10 times the amount of triphenylphosphine based on the number of moles of the intermediate was added to the dark yellow organic agent intermediate thus obtained, flowing nitrogen with stirring, and the temperature of the vessel was gradually raised to 100 ° C., followed by a separate time at 100 ° C. for several hours. React without solvent. The reaction product thus produced is the organic agent of the present invention, which is dissolved in a solvent mixed with water and THF and used for the ion exchange reaction.

The overall synthesis process is as follows.

Na-MMT is sufficiently dispersed in water in the reactor. After dissolving the organic agent of the present invention in a water / THF mixed solvent well, it is stirred in a reactor containing Na-MMT previously dispersed in water. Slowly raise the temperature to 60 ° C. to allow sufficient ion exchange reaction to proceed for several hours. The organizing agent is preferably added to 0.1 to 50% by weight based on the weight of the organic clay. If the weight of the organizing agent is less than 0.1% by weight based on the weight of the organic clay, the characteristics as organicized organic clay, that is, the compatibility with PET is weak, if more than 50% by weight not only decreases the physical properties rapidly but also economically It is disadvantageous.

After completion of the reaction, the filtered reaction product is sufficiently washed with a water / THF mixed solvent to remove the unreacted organic agent and dried to obtain an organic clay.

The method of preparing the polymer / clay nanocomposite is largely a solution method, a polymerization method, a compounding method, etc. The compounding method used in the present invention is to finally insert the polymer resin into the silicate layer by the organic clay and melt mixing method. As a technique, the silicate layer is dispersed in the polymer resin.

After pre-mixing the organic clay to 0.1 to 50% by weight to a sufficiently dried PET resin, it is injected into an extruder to perform melt mixing. If the content of organic clay is less than 0.1% by weight, the mechanical properties of the nanocomposite are insignificant. If the content of the organic clay is more than 50% by weight, the organic clay is not dispersed well, so the mechanical properties are rapidly deteriorated and it is disadvantageous in terms of economics. Do. The temperature of the extruder mixing zone is 270 ℃ and the rotation speed of the screw is preferably 5 to 200 RPM but 20 to 50 RPM.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on the following Example. However, the following examples are not intended to limit the present invention, but are not intended to be limiting. The organic agent prepared in Examples and Comparative Examples of the present invention, organic clay obtained by treating the organic agent of the present invention with Na-MMT, and thus obtained Evaluation of various physical properties of the PET / clay nanocomposite prepared by peeling and dispersing the organic clay was carried out by the following method.

(1) Structural Analysis of Organic Agent Intermediates

¹ H NMR was used to confirm the structure of the synthesized organic agent intermediate, and d -chloroform was used as the solvent.

(2) Content and Thermal Stability of Organic Agent

TGA analysis was performed to investigate the content and thermal stability of the organic agent. Prior to TGA analysis, all samples were sufficiently dried in a vacuum oven (40 ° C.) and all TGA analyzes were performed at a temperature increase rate of 10 ° C./min over a temperature range of 30 ° C. to 800 ° C. while flowing nitrogen gas.

In particular, in order to measure the content of the organic agent, the weights of organic clay and Na-MMT without organic agent treatment were compared with each other at elevated temperatures.

(3) Structural analysis of organic clay and PET / clay nanocomposites

The structures of the organoclay and PET / clay nanocomposites were analyzed by measuring the d spacing for each of the organoclay and PET / clay nanocomposites using an X-ray diffractometer (XRD). Nickel-copper-potassium alpha radiation (wavelength = 0.154 nm, 40 kV, 30 mA) was used as an X-ray source to obtain an XRD pattern, and scanning was performed at a rate of 3 ° / min for a 1.5 to 10 ° region. In addition, the structure of the PET / clay nanocomposites were analyzed using a transmission electron microscope (TEM). PET / clay nanocomposite samples prepared by flake cutters were placed on a 200 mesh copper mesh and observed under an accelerating voltage of 200 kV.

(4) Dynamic Mechanical Properties of PET / Clay Nanocomposites

Dynamic mechanical properties for PET / clay nanocomposites were measured using a dynamic mechanical thermal analyzer (DMTA). Using a sample prepared in the bending mode was carried out at a frequency of 1 Hertz at a temperature rising rate of 3 ℃ / min in the temperature range of 30 to 220 ℃.

Example 1 and Comparative Example 1

Preparation of Organizing Agent Intermediates

0.015 mol of 2,2-bis (4-glycidyloxyphenyl) propane is placed in a container with purified acetonitrile and stirred with flowing nitrogen gas to form a uniform solution. At the same time, 0.015 mol of magnesium perchlorate and 0.3 mol of 2-bromoethanol were added to a separate vessel and stirred while flowing nitrogen. Slowly raise the temperature of the vessel containing magnesium perchlorate and 2-bromoethanol to 80 ° C., and prepare a 2,2-bis (4-glycidyloxyphenyl) propane / acetonitrile solution in a small amount while flowing nitrogen gas. Put it slowly. The reaction proceeded at 80 ° C. for 24 hours. The reaction product was extracted with diethyl ether, washed several times with distilled water, the diethyl ether layer was separated, dried over anhydrous magnesium sulfate, and diethyl ether and unreacted product were removed by an evaporator to obtain a dark yellow organic agent intermediate.

Preparation of Organizer

0.006 mol of triphenylphosphine was added to 0.005 mol of the dark yellow organic agent intermediate thus obtained, flowing nitrogen with stirring, and the temperature of the vessel was gradually raised to 100 ° C. and reacted without any solvent at 100 ° C. for 12 hours. The reaction product thus produced is the organic agent of the present invention and was used in the ion exchange reaction by dissolving distilled water and THF in a solvent mixed 1: 1 by volume.

Preparation of Organic Clay

2.5 g of Na-MMT was sufficiently dispersed in 250 ml of distilled water. A sufficient amount of the organic agent of the present invention was dissolved in distilled water / THF mixed solvent in a volume ratio of 1: 1, and then stirred in a reactor containing Na-MMT dispersed in distilled water. The temperature was slowly raised to 60 ° C. to allow sufficient ion exchange reaction to proceed for 24 hours. After completion of the reaction, the filtered reaction product was sufficiently washed with distilled water / THF mixed solvent in a volume ratio of 1: 1 to remove the unreacted organic agent and dried to obtain an organic clay.

The organic clay was measured while increasing the temperature to obtain a result as shown in FIG. As a result of measuring the weight by heating Na-MMT, the weight was decreased by 8% by weight, and the weight was reduced by increasing the temperature of organic clay, and the weight was reduced by 30% by weight. It was found that the organic clay contained 22% by weight.

Preparation of PET / clay nanocomposites

1 g of organic clay was premixed with 65 g of PET resin sufficiently dried beforehand, followed by injection into an extruder to perform melt mixing. The extruder used a twin screw type, the mixing zone temperature was 270 ℃ and the rotation speed of the screw was 30 RPM. The first 30 g of the extruded PET / clay nanocomposite was discarded and the next 30 g was taken.

DMTA experiment was performed under the same conditions on the PET / clay nanocomposite prepared as described above and the PET resin in which clay was not dispersed.

3 (A) and 3 (B) show the dynamic storage modulus and the dynamic loss modulus, respectively. The PET / clay nanocomposites prepared in this study showed significantly higher strength over the entire temperature range tested than the PET resin.

As described above, the present invention provides a method for producing a PET / clay nanocomposite having the excellent gas barrier properties and other mechanical properties without deteriorating physical properties such as impact resistance, toughness and transparency by the compounding method, which is the most commercially advantageous method. Provided is a technique relating to a PET / clay nanocomposite produced by the method.

After designing and synthesizing an organic agent having excellent thermal stability, preparing organic clay using the organic agent, and dispersing the organic clay in a PET resin to produce a PET / clay nanocomposite, resulting in a dynamic storage modulus and a dynamic loss modulus In terms of, it has a remarkably superior property.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims. .

1 is a structural formula of an organic agent used in the production of PET / clay nanocomposites according to the present invention.

Figure 2 is a graph of the TGA test results carried out to determine the content of the organic agent in the organic clay used in the production of PET / clay nanocomposites according to the present invention.

3 is a graph of DMTA test results for PET / clay nanocomposites and PET resins in which clay is not dispersed, and (A) and (B) are graphs of dynamic storage modulus and dynamic loss modulus, respectively.

Claims (5)

Peelable PET / clay nanocomposite having excellent dynamic mechanical properties, characterized in that it comprises 0.1 to 50% by weight relative to the clay weight of the organic agent of the formula (I). Structural Formula (I) In the method for producing PET / clay nanocomposites using the compounding method, an organic clay having improved thermal stability shown in the above formula (I) is added to clay to prepare an organic clay, and the organic clay is compounded. Dispersing in PET resin to produce a peelable PET / clay nanocomposite excellent in dynamic mechanical properties. The method of claim 2, The clay is a manufacturing method characterized in that Na-MMT. The method of claim 2, The organic clay is prepared by mixing Na-MMT and the organic agent shown in the formula (I) in a water / THF mixed solvent. The method of claim 2, The content of the organic clay with respect to the PET resin is a manufacturing method, characterized in that 0.1 to 50% by weight.