KR101495783B1 - Method for manufacturing oxygen barrier film by using nanoclay surface modification - Google Patents

Abstract

The present invention relates to a method of manufacturing a nanocomposite using surface modification of a nanoclay, the method comprising: a surface modification step of modifying the nanoclay surface by a corona discharge treatment or a plasma treatment; and a step of forming the nanoclay by dispersing the nanoclay in polyvinyl alcohol or ethylene vinyl alcohol The present invention also provides a method for preparing nanocomposites using surface modification of nanoclay.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing an oxygen barrier film using a nano-

More particularly, the present invention relates to a method of manufacturing a nanocomposite using surface modification of nano-clay, and more particularly, to a method of manufacturing nanoclay using nanoparticles having improved hydrophilicity and adhesiveness of the nanoclay by modifying the nanoclay surface using a corona discharge treatment or a plasma treatment, To polyvinyl alcohol or ethylene vinyl alcohol which is uniformly dispersed and has increased oxygen barrier properties, heat resistance, impact resistance and transparency.

The polymer nanocomposite is a new material that combines or bonds different materials such as polymers, metals, and ceramics to a conventional elastic material at a nanometer level. Conventionally, it has been a subject of academic interest because it is difficult to uniformly disperse small particles having a size of dispersed phase of 100 nm or less, but nowadays, it has been spotlighted as an object of commercialization due to rapid technological development.

However, the layered silicate, which is a basic unit of clay minerals, has a problem of being not uniformly dispersed in the polymer resin due to strong Van der Waals attraction.

Conventionally, the polymer clay was mainly prepared by a compounding method in which molten polymer clay was inserted between silicate layers and mechanically mixed to disperse the clay particles.

However, when the matrix polymer is non-polar, there is a problem that the polymer is not well penetrated between the layers because the clay is positively charged. In order to solve such a problem, a method has been disclosed in which a clay master batch in which a clay is inserted into a layered silicate layer of a clay polyolefin oligomer grafted with a polar group such as maleic anhydride and then mixed with the polyolefin polymer.

However, according to this method, the polar polymer can be intrcalated into the silicate layer, but in order to completely remove the silicate layer, it is necessary to mix the polymer at a high shear rate for a long time in the extruder.

In addition, there is a fear that the physical properties such as decomposition of the polymer may be deteriorated in such a process, and the oligomer added to intercalate the clay has a disadvantage of lowering the heat distortion temperature and mechanical strength of the finally produced nanocomposite.

Korean Patent Publication No. 10-2004-0110891 Korean Patent Publication No. 10-2005-0042880

Accordingly, an object of the present invention is to solve the conventional problem that a nanoclay having a strong Van der Waals attractive force is not uniformly dispersed in a polymer resin, and it is an object of the present invention to provide a nanoclay, which is corona discharge treatment or plasma treatment, To thereby form a nanocomposite uniformly dispersed in polyvinyl alcohol or ethylene vinyl alcohol.

Another object of the present invention is to provide a method for producing an oxygen barrier film having increased oxygen barrier properties, heat resistance, impact resistance and transparency by applying a nanocomposite dispersed through surface modification to a polyolefin.

This object is solved according to one embodiment of the present invention by a method for producing a nanoclay comprising the steps of: a surface modification step of modifying the nanoclay surface by a corona discharge treatment or a plasma treatment; and a step of forming the nanoclay by dispersing the nanoclay in polyvinyl alcohol or ethylene vinyl alcohol to form a nanocomposite And a dispersing step of dispersing the nanoclay on the surface of the nanoclay.

In addition, the corona discharge treatment may have a discharge degree of 1 to 5 W / cm 2.

In addition, the plasma treatment may be performed by injecting oxygen (O ₂ ) gas, argon (Ar) gas or nitrogen (N ₂ ) gas in a vacuum state.

The nano-clay is also a layered silicate and the layered silicate is selected from the group consisting of montmorillonite, hectorite, bentonite, saponite, magadiite, synthetic mica, saponite, vermiculite, kenyaite, kaolinite, Or at least one of them.

Also, the polyvinyl alcohol or the ethylene vinyl alcohol may be 75 to 95% by weight based on 100% by weight of the nanocomposite, and the nano-clay may be 5 to 25% by weight.

The present invention also provides a method for producing a nanoclay comprising: a surface modification step of modifying the nanoclay surface by a corona discharge treatment or a plasma treatment; a dispersion step of dispersing the nanoclay in polyvinyl alcohol or ethylene vinyl alcohol to form a nanocomposite; And a coating step of applying the nanocomposite having a thickness of 1 탆 to the surface of the nanoclay.

In addition, the corona discharge treatment may have a discharge degree of 1 to 5 W / cm 2.

In addition, the plasma treatment may be performed by injecting oxygen (O ₂ ) gas, argon (Ar) gas or nitrogen (N ₂ ) gas in a vacuum state.

According to the present invention, the surface of the nano-clay can be corona discharge treated or plasma treated to uniformly disperse it on the polyvinyl alcohol or ethinyl vinyl alcohol as an organic solution.

Further, by using a uniformly dispersed nanocomposite, it is possible to produce an oxygen barrier film having increased oxygen barrier property, water barrier property, heat resistance, impact resistance and transparency.

Further, by applying the nanocomposite to a polyolefin film to produce an oxygen barrier film, it can be utilized as a UNI material which can be recycled.

1 is a flow chart of a method for producing a nanocomposite according to the present invention,
2 is a schematic diagram of layered montmorillonite (MMT).
3 is a graph showing the particle size in the dispersion according to the agitation time of [Comparative Example 1].
4 is a graph showing the particle size in the dispersion according to the ultrasonic treatment time of [Comparative Example 2].
5 is a graph showing the particle size in the dispersion according to the plasma treatment time of [Example 1].
6 is a graph showing the particle size in the dispersion according to the corona discharge treatment time of [Example 2].
FIG. 7 is a graph showing the percent reduction of the nanocomposite according to the agitation time of [Comparative Example 1]. FIG.
FIG. 8 is a graph showing the percent reduction of the nanocomposite according to the ultrasonic treatment time of [Comparative Example 2]. FIG.
FIG. 9 is a graph showing the percent reduction of nanocomposite according to the number of times of plasma treatment and agitation time in [Example 1].
10 is a graph showing the percent reduction of nanocomposites according to the number of corona treatments and agitation time of [Example 2].
11 is a graph showing the viscosity according to the shear rate of [Comparative Example 3], [Example 3] and [Example 4].
12 is a graph showing the viscosity according to shear rates of [Comparative Example 3], [Example 5] and [Example 6].

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings, which show a method for producing a nanocomposite using surface modification of a nanoclay according to the present invention. The present invention may be better understood by the following examples, which are for the purpose of illustrating the present invention and are not intended to limit the scope of protection defined by the appended claims.

As shown in the flow chart of FIG. 1, the method for producing a nanocomposite using the surface modification of the nanoclay of the present invention comprises a surface modification step (S10) and a dispersion step (S20).

The surface modification step (S10) is a step of modifying the nanoclay surface through corona discharge treatment or plasma treatment so as to uniformly disperse the nanoclay into the organic solution.

At this time, the corona discharge treatment utilizes the electric discharge generated due to the ionization of the fluid around the conductor, which uses a corona discharge which occurs when the potential hardness exceeds a certain value but is insufficient to cause complete insulation breakdown or arc will be. More specifically, the polyethylene is adhered to the surface of the nano-clay and the corona discharge is applied to the contact surface of the polyethylene. When the nano-clay and the polyethylene are peeled off, nano-clay is retained in the entire polyethylene surface by 80 to 100% Wettability is improved.

At this time, it is preferable to use a corona discharge treatment having a discharge degree of 1 to 5 W / W per unit area, that is, a discharge degree of 1 to 5 W / cm 2. The degree of discharge shows the discharge power that does not generate pinholes and the area of the discharge electrode. When high heat is applied to the surface of the nano-clay, the hardness decreases. Therefore, generation of heat can be suppressed by using a high frequency power source.

In addition, the plasma surface treatment generates plasma by increasing the voltage to two electrodes having different potential difference in a vacuum state, and functions of removing foreign matter, surface modification, nickname, etc. are changed according to the kind of gas for plasma generation.

Plasma surface treatment is divided into surface cleaning, surface modification, surface nickname, and surface layer. First of all, when plasma is formed by injecting gas in a vacuum state, ionized gas particles physically and chemically In this method, the surface is impacted, and the foreign matter is evaporated or torn off. At this time, the gas is injected with one of oxygen (O ₂ ) gas, argon (Ar) gas or nitrogen (N ₂ ) gas, or preferably argon (Ar) gas.

In addition, when plasma is formed by injecting gas or the like in a vacuum state, the gas is adsorbed on the surface of the nano-clay, thereby improving the adhesion. At this time, any one of oxygen (O ₂ ) gas, argon (Ar) gas or nitrogen (N ₂ ) gas is injected or preferably oxygen (O ₂ ) gas is injected.

The dispersing step S20 is a step of dispersing nanoclays whose surface has been modified by corona discharge treatment or plasma treatment into polyvinyl alcohol (PVA) or ethylene vinyl alcohol (EVOH) which is an organic solution. This is to reduce the permeability of the nanoclay when impurities such as oxygen or water vapor are impregnated by dispersing the nanoclay in the container solution.

At this time, the nanoclay may have a layered structure, the length in the longitudinal direction may be 100 to 200 nm, preferably 125 to 170 nm, and the unidirectional length may be 0.5 to 2 nm or preferably 1 nm.

The nano-clay is also an organic or inorganic silicate nano-clay, preferably montmorillonite, hectorite, bentonite, saponite, magadiite, synthetic mica, saponite, vermiculite, kenyaite, kaolinite, Or more preferably at least one of montmorillonite, hectorite and bentonite.

FIG. 2 shows a structure of Na + type-montmorillonite (MMT, hereinafter referred to as MMT) as an organic clay to manufacture a nanocomposite using nanoclay, and the main constituent mineral is a silicate mineral. As shown in FIG. 2, a layered structure having a three-layered structure (Si-Al-Si) with a 2: 1 ratio of a silicon (Si) tetrahedron and an aluminum (Al) octahedron is formed of Al ₂ Si ₄ (OH) In the gibbsite layer which is the intermediate layer of aluminum oxide, the +3 Al is substituted by the +2 magnesium, so that the surface of the MMT has exchangeable ions as much as -1, According to the composition, the form satisfied with Na + is Na + type-MMT, and the form satisfied with Ca + is Ca + type-MMT. Since Na + -MMT has relatively higher swelling and dispersibility than that of Ca + -MMT when hydrated, Ca + -MMT is generally Na ₂ CO ₃ , which is converted to Na + substituted MMT through an artificial substitution process In order to produce nanocomposites using Na + type MMT, the nanoclays are modified by a modification process and the polymer is processed to be inserted between the layers and layers of the nanoclay.

In this case, the polyvinyl alcohol or ethylene vinyl alcohol is 75 to 95% by weight based on 100% by weight of the nanocomposite, the nano-clay is 5 to 25% by weight, preferably the polyvinyl alcohol or ethylene vinyl alcohol is 90 to 95% , The nano-clay may be 5 to 10 wt%, more preferably 95 wt% of the polyvinyl alcohol or ethylene vinyl alcohol, and 5 wt% of the nano-clay.

When the content of nanoclay is higher than 100 wt% of the nanocomposite prepared by the dispersion step, the light transmittance is drastically lowered, and when the content is lower, the OTR and WCTR are increased.

In addition, it is possible to manufacture an oxygen barrier film having high oxygen barrier property and moisture barrier property by using the nanocomposite produced by the nanocomposite manufacturing method using the surface modification of the nanoclay, and it is possible to manufacture the oxygen barrier film by the corona discharge treatment or the plasma treatment A dispersion step in which the nanoclay is dispersed in polyvinyl alcohol or ethylene vinyl alcohol to form a nanocomposite, and a step of applying the nanocomposite having a thickness of 1 to 4 m to the polyolefinic film Lt; / RTI >

Here, the polyolefin-based film may be polyethylene, polypropylene, polyisobutylene, polyolefin, polymethylpentene-methylpentene, preferably polymethylpentene or methylpentene.

The polyolefin film is the lightest plastic with a density of 0.83 and has a heat resistance of 350 ° C at the melting point and a heat deformation temperature of 200 ° C at the charge and has transparency similar to that of the methacrylic resin and is excellent in oxygen and moisture barrier properties, And is excellent in impact resistance and can be recycled, which is effective in reducing greenhouse gas.

Further, the thickness of the nanocomposite in the oxygen barrier film may be 1 to 4 占 퐉, or preferably 1.13 to 3.47 占 퐉. This is because if the thickness of the nanocomposite is large, practicality and compatibility of the nanocomposite are poor, and when the thickness is small, the barrier property of oxygen and moisture is low.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto.

[Example 1]

The pure Na ⁺ -MMT clay was treated with plasma at an output of 864 W to 972 W at 1, 3, 5, and 10 times to prepare Na ⁺ -MMT modified by plasma, and 0.1 g of surface modified Na ⁺ 10 g of ultrapure water was stirred with time. Further, 10 g of ultrapure water and 1 g of polyvinyl alcohol (PVA) were stirred at 80 캜 for 30 minutes at 300 rpm using a magnetic bar. Thereafter, a nanocomposite coating solution was prepared by mixing a Na ⁺ -MMT solution and a polyvinyl alcohol solution, and the nanocomposite coating solution was coated on a corona-treated polyolefin (PP) film having a thickness of 20 탆 using a mabar bar, Lt; 0 > C for 2 minutes.

[Example 2]

Pure Na ⁺ -MMT the clay to 302.4 to 345W output is a low-nose discharge producing a Na ⁺ -MMT the modified surface by 1,3,5, treatment by corona discharge treatment, and 10 times, the surface-modified Na ⁺ -MMT and 10 g of ultrapure water were stirred with time. Further, 10 g of ultrapure water and 1 g of polyvinyl alcohol (PVA) were stirred at 80 캜 for 30 minutes at 300 rpm using a magnetic bar. Thereafter, a nanocomposite coating solution was prepared by mixing a Na ⁺ -MMT solution and a polyvinyl alcohol solution, and the nanocomposite coating solution was coated on a corona-treated polyolefin (PP) film having a thickness of 20 탆 using a mabar bar, Lt; 0 > C for 2 minutes.

[Comparative Example 1]

A solution of 10 g of ultrapure water and 0.05 g of Na ⁺ -MMT clay was stirred at room temperature over time. Further, 10 g of ultrapure water and 1 g of polyvinyl alcohol (PVA) were stirred at 80 캜 for 30 minutes at 300 rpm using a magnetic bar. Thereafter, Na ⁺ -MMT clay solution and polyvinyl alcohol solution were mixed and stirred at 300 rpm at room temperature to prepare a nanocomposite coating solution. The nanocomposite coating solution was applied to a corona-treated 20 μm thick Of polyolefin (PP) film and dried on a hot-plate at 100 ° C for 2 minutes.

[Comparative Example 2]

10 g of ultrapure water and 0.05 g of Na ⁺ -MMT clay were ultrasonicated with stirring at room temperature over time. Further, 10 g of ultrapure water and 1 g of polyvinyl alcohol (PVA) were stirred at 80 캜 for 30 minutes at 300 rpm using a magnetic bar. Thereafter, the Na ⁺ -MMT clay solution and the polyvinyl alcohol solution were mixed and stirred at room temperature for 10 minutes. Then, ultrasonic treatment was performed at room temperature for 30 minutes to prepare a nanocomposite coating solution, and the nanocomposite coating solution was applied to Meyer bar coated with a corona-treated polyolefin (PP) film having a thickness of 20 탆 and dried on a hot plate at 100 캜 for 2 minutes.

Particle size comparison in dispersion

Hereinafter, the particle sizes in the dispersion are compared through Examples 1 and 2 and Comparative Examples 1 and 2.

FIG. 3 is a graph showing the particle size in the dispersion according to the agitation time of ultrapure water of Comparative Example 1 and Na.sup. ^{+ -} MMT, and shows that the particle size is the smallest when stirred for 30 minutes.

FIG. 4 is a graph showing the particle size in the dispersion according to the ultrasonic treatment time of a solution obtained by mixing ultrapure water and Na ⁺ -MMT of Comparative Example 2. As the ultrasonic treatment time becomes longer, the particle size becomes smaller, The size of the particles is drastically reduced.

FIG. 5 is a graph showing the particle size according to agitation time of a solution prepared by mixing ultra-pure water of Example 1 and Na ⁺ -MMT having different plasma treatment times. In the case of treating plasma once or three times or more , The particle size reduction efficiency is remarkably different according to the agitation time, and the particle size is rapidly reduced for about 10 minutes.

FIG. 6 is a graph showing the particle size according to agitation time of a solution obtained by mixing ultrapure water of Example 2 with Na ⁺ -MMT having a different number of corona discharge treatments. In FIG. 6, The efficiency of particle size reduction according to agitation time is significantly different, and the particle size rapidly decreases for about 10 minutes.

The particle size of Comparative Example 1 in which Na ⁺ -MMT without surface modification was used was 2500 to 3000 nm, whereas the particle size of Comparative Example 2 and Examples 1 and 2, in which the surface was modified, was 400 nm or less. In one case, the size of the particles decreases and this indicates that the dispersion is increased.

Therefore, as shown in Examples 1 and 2 and Comparative Examples 1 and 2, the particle size of the surface modified nanocomposite dispersion through the plasma or corona discharge treatment is smaller than that of Comparative Example 1 Or higher than that of Comparative Example 2 treated with ultrasonication.

Tertiary rate ( OTR ) compare

Hereinafter, Examples 1 and 2 and Comparative Example 1 and Comparative Example 2 are compared.

Figure 7 is a graph as a measure Tucson soyul of the produced film by the Comparative Example 1, in the case of ultra-pure water and stirred for 30 minutes or more Na ⁺ clay -MMT Tucson soyul is rapidly decreased, but from about 4cc / m ² day at a relatively high And the ratio of tetroxide.

FIG. 8 is a graph showing the measurement of the percent reduction of the film produced by Comparative Example 2. As the time for treating ultrasound into the mixed solution of ultrapure water and Na ⁺ -MMT clay is increased, It can be seen that the abatement rate sharply decreases to about 2 cc / m ² day.

FIG. 9 is a graph showing a measurement of the tetroxide content of the film produced in Example 1, showing a change in the tetroxide content according to the number of times of plasma treatment in the Na ⁺ -MMT clay, , It can be seen that, even when treated once, the rate of tetroxide is less than ² cc / m ² day as compared with Comparative Examples 1 and 2.

FIG. 10 is a graph showing a measurement of the percent reduction of the film produced according to Example 2, showing a change in the rate of permeation according to the number of corona discharge treatments in the Na ⁺ -MMT clay, and 2cc / m ² day Of the total.

Therefore, as described in Examples 1 and 2 and Comparative Examples 1 and 2, the oxygen permeability of the film using the nanocomposite modified by surface treatment through the plasma or corona discharge treatment is low, Which is superior to Comparative Example 1 or to Ultrasonic Comparative Example 2.

[Example 3]

0.1 g of a Na ⁺ -MMT clay whose surface was modified with a plasma having an output of 864 to 972 W and 10 g of ultrapure water were stirred at 300 rpm at room temperature for 2 hours to measure the viscosity according to the shear rate.

[Example 4]

0.1 g of the surface modified Na ⁺ -MMT clay and 10 g of ultrapure water were stirred at 300 rpm for 2 hours at room temperature and the viscosity was measured according to the shear rate by a corona discharge with an output of 302.4 to 345.6 W.

[Example 5]

0.06 g of a Na ⁺ -MMT clay modified with a plasma having an output of 864 to 972 W and 10 g of ultrapure water were stirred at 300 rpm at room temperature for 2 hours to measure the viscosity according to the shear rate.

[Example 6]

0.06 g of a Na ⁺ -MMT clay modified with a surface treated with corona discharge having an output of 302.4 to 345.6 W and 10 g of ultrapure water were stirred at 300 rpm for 2 hours at room temperature to measure the viscosity according to the shear rate.

[Comparative Example 3]

0.1 g of pure Na ⁺ -MMT clay and 10 g of ultrapure water were stirred at 300 rpm for 2 hours at room temperature to measure the viscosity according to the shear rate.

Viscosity comparison according to shear rate

Hereinafter, the viscosity according to the shear rate is compared through Examples 3 to 6 and Comparative Example 3.

11 is a graph showing viscosity measured according to the shear rate of Comparative Examples 3 and 3 and Examples 3 and 4. The viscosities of Examples 3 and 4 which are nano clays subjected to plasma or corona discharge treatment are higher than those of Comparative Example 1, Which is the result of high dispersion.

12 is a graph showing the viscosity measured according to the shear rate of Comparative Example 3 and Examples 5 and 6, showing that Examples 5 and 6 have similar viscosities even in the case of Comparative Example 3 in which the surface was not modified.

Therefore, as shown in Examples 3 to 6 and Comparative Example 3, it can be seen that the surface modified nanocomposite dispersion through the plasma or corona discharge treatment has a higher viscosity.

It is to be understood that the present invention is not limited thereto and that various changes and modifications may be made within the scope of the appended claims, the detailed description of the invention and the accompanying drawings, It is natural to belong to the scope.

Claims (10)

delete delete delete delete delete As a method for producing an oxygen barrier film,
A surface modification step of modifying the nanoclay surface by a corona discharge treatment or a plasma treatment;
A dispersion step in which the nanoclay is dispersed in polyvinyl alcohol or ethylene vinyl alcohol to form a nanocomposite; And
And applying the nanocomposite having a thickness of 1 to 4 占 퐉 to the polyolefin-based film,
Wherein the oxygen barrier film has a Toluene content of 2 cc / m ² day or less. The method according to claim 6,
Wherein the corona discharge treatment has a discharge degree of 1 to 5 W / cm < 2 >. The method according to claim 6,
Wherein the plasma treatment is performed by injecting oxygen (O ₂ ) gas, argon (Ar) gas or nitrogen (N ₂ ) gas in a vacuum state.












The method according to claim 6,
Wherein the nanoclay is a layered silicate,
Wherein the layered silicate is at least one of montmorillonite, hectorite, bentonite, saponite, magadiite, synthetic mica, saponite, vermiculite, kenyaite, kaolinite, A method for preparing nanocomposite using surface modification of nanocomposite. The method according to claim 6,
Wherein the polyvinyl alcohol or the ethylene vinyl alcohol is 75 to 95% by weight based on 100% by weight of the nanocomposite, and the nanoclay is 5 to 25% by weight based on 100% by weight of the nanocomposite.

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