KR20120056119A - Gas barrier coating composition and gas barrier film - Google Patents

Abstract

PURPOSE: A gas barrier coating composition is provided to form a gas barrier film with excellent adhesion and transparency on various thermoplastic resin substrates. CONSTITUTION: A gas barrier coating composition comprises a polyvinylalcohol, a polyalkylene imine based polymer, a mixed solvent of C1-5 lower alcohol and water. The polyvinylalcohol has a saponification degree of over 60%, and a polymerization degree of 100-5000. The polyvinyl alcohol has a number average molecular weight of 5,000-30,000. The polyvinyl alcohol comprises non-modified polyvinylalcohol, modified polyvinylalcohol or a mixture thereof. A gas barrier film comprises a thermoplastic resin substrate, and a coating layer on the coating layer on a substrate comprising polyvinyl alcohol and polyalkylene imine based polymer.

Description

Gas barrier coating composition and gas barrier film {GAS BARRIER COATING COMPOSITION AND GAS BARRIER FILM}

The present invention relates to a gas barrier coating composition and a gas barrier film. More specifically, the present invention relates to a gas barrier coating composition and a gas barrier film which enable to form a gas barrier coating layer having excellent adhesion and transparency on a thermoplastic resin substrate.

Films and sheets made of thermoplastic resins such as polyesters, polyamides or polyolefins have been applied as various packaging materials.

However, since most of the films or sheets of these thermoplastic resins do not have sufficient gas barrier properties, they have limitations in being applied to food packaging materials and various other packaging materials requiring blocking of oxygen.

For this reason, various gas barrier coating compositions have been proposed for coating the thermoplastic resin film or sheet to improve their gas barrier properties. However, even when a coating layer is formed on a thermoplastic resin film or sheet with a gas barrier coating composition previously known, gas barrier properties are insufficient or transparency is inferior in quality as a packaging material.

In addition, the gas barrier coating composition previously known is often not easy to form the coating layer due to poor adhesion or adhesion to the thermoplastic resin film or sheet or gelation during storage. Further, even when the coating layer is formed, there are many disadvantages in that the gas barrier property is not substantially improved due to the generation of pinholes or the like.

In addition, in the case of the gas barrier coating composition previously known, the thermoplastic resin is often exhibited significantly different gas barrier properties, transparency or adhesion depending on the material of the film or sheet on which the coating layer is formed, that is, the type of the thermoplastic resin. There was also a disadvantage of poor versatility for films or sheets.

For example, it has been proposed to be able to form a coating layer having a certain level of transparency and gas barrier properties on a film or sheet made of a polyester resin in a gas barrier coating composition. However, even in such a coating composition, the adhesiveness with respect to a polyolefin film or a sheet was inferior significantly. In addition, a pinhole or the like is generated in the coating layer, which causes a number of disadvantages in that gas barrier properties are hardly improved. Previously, a method of adding an anchor layer (adhesive layer) for improving adhesion between the thermoplastic resin film or sheet (for example, polyolefin-based film) and the coating layer has been considered to compensate for this, but in this case, the process is complicated. In addition, the anchor layer or the like has often lowered the transparency and other physical properties of the thermoplastic resin film or sheet (for example, a polyolefin film or the like) significantly.

Accordingly, the present invention is to provide a gas barrier coating composition that can form a gas barrier coating layer excellent in adhesion and transparency on various thermoplastic resin substrates.

The present invention also provides a gas barrier film that exhibits excellent gas barrier properties and transparency while exhibiting excellent adhesion between the thermoplastic resin substrate and the coating layer.

The present invention is polyvinyl alcohol; Polyalkyleneimine-based polymers; And it provides a gas barrier coating composition comprising a mixed solvent of a lower alcohol having 1 to 5 carbon atoms and water.

In addition, the present invention is a thermoplastic resin substrate; And it provides a gas barrier film comprising a coating layer on the substrate formed from the coating composition.

The present invention also provides a thermoplastic resin substrate; And it provides a gas barrier film comprising a coating layer on the substrate comprising a polyvinyl alcohol and polyalkyleneimine-based polymer.

Hereinafter, a gas barrier coating composition and a gas barrier film according to a specific embodiment of the present invention will be described.

Unless otherwise expressly stated, some terms used throughout this specification are defined as follows.

Unless specifically stated throughout this specification, "comprising" or "containing" means including any component (or component) without particular limitation, and excludes the addition of other components (or components). Cannot be interpreted as.

In addition, throughout this specification, "polyvinyl alcohol" refers to any polymer comprising repeating units of polyvinyl alcohol well known to those skilled in the art. The scope of such polymers may encompass not only a single polymer consisting of the above repeating units but also any type of copolymer such as a block copolymer or a graft copolymer. In addition, in the category of the polymer called "polyvinyl alcohol," not only a polymer that is not modified, but also at least a part of the repeating units of the polyvinyl alcohol may be modified with various organic functional groups such as carboxyl groups or silyl groups, polyethylene or polypropylene, etc. Polymers can also be encompassed.

And, "polyalkyleneimine-based polymer" refers to any polymer containing a repeating unit of the polyalkyleneimine, for example, the repeating unit of the formula (1) well known to those skilled in the art. The scope of such polymers may encompass not only a single polymer consisting of the above repeating units but also any type of copolymer such as a block copolymer or a graft copolymer.

[Formula 1]

In Formula 1, n is an integer of 1 to 5, m is 5 to 5000, preferably 10 to 3000.

In addition, in the category of the polymer referred to as the "polyalkyleneimine-based polymer," not only a polymer that is not modified, but also organic functional groups such as titanium, a carboxyl group or an epoxy group, or an inorganic material, such as titanium, are bonded to the terminal, or modified. Polymers in which at least some of the repeat units are modified with various functional groups such as vinyl may also be encompassed.

In addition, the "thermoplastic resin base" may be defined to encompass a thermoplastic resin sheet or film having any form that has been known to be applicable to various applications such as packaging materials. The category of the "thermoplastic resin base" includes polyester resins, polyamide resins, polyolefin resins, and the like, and may also include a thermoplastic resin sheet or film that is stretched or unstretched or has any other form.

And, throughout this specification, the fact that a layer is "directly formed" on a substrate means that another layer, film or substrate is not formed or interposed separately between the substrate and the layer, It means that the layer is formed on the substrate so that the layers directly abut. In contrast, "another layer, film or substrate is formed between a layer and a substrate" means that another layer, film or substrate is formed between these layers and the substrate so that the layer does not touch the surface of the substrate or It means that it is interposed.

On the other hand, according to one embodiment of the invention, polyvinyl alcohol; Polyalkyleneimine-based polymers; And a mixed solvent of a lower alcohol having 1 to 5 carbon atoms and water.

According to the experimental results of the present inventors, using the coating composition comprising the three components described above, in particular, polyvinyl alcohol and polyalkyleneimine-based polymer together, the adhesiveness while showing excellent gas barrier properties and transparency on the thermoplastic resin substrate It has been found that good coating layers can be formed well.

This shows that the polyvinyl alcohol exhibits excellent gas barrier property (for example, oxygen barrier property), and the polyalkyleneimine-based polymer improves the adhesion between the coating composition and the thermoplastic resin substrate and thus does not generate pinholes. It seems to allow the formation of. In addition, the polyalkyleneimine-based polymer does not cause gelation of the coating composition.

Therefore, by using such a coating composition, it is possible to provide a film showing excellent gas barrier properties by forming a good coating layer on the thermoplastic resin substrate without the occurrence of pinholes or the like. Such a gas barrier film may exhibit excellent gas barrier properties by the coating composition and the coating layer while maintaining the advantages of various thermoplastic resin substrates such as a polyester resin substrate, a polyamide resin substrate, or a polyolefin resin substrate. It can be applied very preferably as a packaging material of various products.

In particular, the coating composition may be used to form a coating layer exhibiting excellent gas barrier properties on various thermoplastic resin substrates without being particularly limited by the material of the thermoplastic resin substrate. For example, it was difficult to form a coating layer exhibiting excellent gas barrier properties on a polyolefin resin substrate without a separate anchor layer. However, by using the coating composition according to an embodiment of the present invention, it is possible to form a coating layer exhibiting excellent gas barrier properties on a variety of thermoplastic resin substrates including polyolefin resins, without a separate anchor layer, There is little fear that the anchor layer will lower the transparency and other physical properties of the thermoplastic resin substrate. Therefore, by using such a coating composition to form a coating layer having excellent gas barrier properties and the like on various thermoplastic resin substrates, it is possible to universally obtain a gas barrier film applicable to various packaging materials while exhibiting excellent physical properties. .

In addition, as supported by the following examples, the coating composition enables formation of a coating layer exhibiting excellent transparency on the thermoplastic resin substrate, thereby providing a gas barrier film exhibiting excellent transparency.

Hereinafter, a specific configuration of the gas barrier coating composition according to the embodiment of the present invention will be described.

The coating composition comprises polyvinyl alcohol to form a coating layer exhibiting gas barrier properties. Such polyvinyl alcohol may have a saponification degree of 60% or more, preferably 70% or more, more preferably 70 to 99.9%, and may have a polymerization degree of 100 to 5000.

In this case, the degree of saponification means the degree to which the acetate group in the molecule of polyvinyl alcohol is substituted with a hydroxy group. As the degree of saponification increases, the polyvinyl alcohol may exhibit hydrophilicity, and thus has excellent polarity against nonpolar oxygen. That is, gas barrier properties can be exhibited. On the other hand, when the saponification degree is lowered, the gas barrier property of the coating layer formed of the coating composition tends to be lowered, which is not preferable.

In addition, when the degree of polymerization of the polyvinyl alcohol is too low, the coating composition may not exhibit sufficient adhesion to the resin substrate, on the contrary, when the degree of polymerization is too high, the coating composition may have a high viscosity and the coatability may be reduced.

And, the polyvinyl alcohol may have a number average molecular weight of 5000 ~ 300000, preferably 5000 ~ 100,000, more preferably 10000 ~ 8800. The higher the number average molecular weight may be excellent in the water resistance and mechanical properties of the coating layer, but when the molecular weight is too high, the viscosity of the coating composition may increase to deteriorate coating properties.

On the other hand, as the polyvinyl alcohol, not only modified polyvinyl alcohol, but also modified with various organic functional groups or other polymers may be used, and a mixture of unmodified polyvinyl alcohol and modified polyvinyl alcohol may also be used.

At this time, examples of the modified polyvinyl alcohol include polyvinyl alcohol modified with organic functional groups such as carboxyl group, silyl group, sulfonic acid group, amino group, phosphoric acid group, isocyanate group, oxazoline group, methylol group, nitrile group, acetacetyl group or cationic group. And block copolymers or graft copolymers modified with acryl, urethane, polyester, epoxy, polyethylene, polypropylene, and the like.

Among such modified polyvinyl alcohols, polyvinyl alcohol modified with a silyl group or a carboxyl group can be preferably used in terms of adhesion between the resin substrate and the coating composition, and such modified polyvinyl alcohol can be used with respect to the weight of the total polyvinyl alcohol. When included in an amount of 10% by weight or more, suitably 20% by weight or more, the effect of the addition of modified polyvinyl alcohol can be obtained. In addition, the polyvinyl alcohol modified with the silyl group or carboxyl group may be modified with 0.01 to 5 mol% silyl group or 0.1 to 50 mol% carboxyl group. By using such modified polyvinyl alcohol, the adhesion of the coating composition to the resin substrate can be enhanced to form a good coating layer.

The modified polyvinyl alcohols described above can be prepared or commercially obtained by methods known to those skilled in the art.

On the other hand, the coating composition includes a polyalkyleneimine-based polymer in order to improve the adhesion to the resin substrate and to form a gas barrier coating layer excellent in transparency. As such a polyalkyleneimine-based polymer, as described above, it is possible to use substantially all types of polymers including repeating units of polyalkyleneimines well known to those skilled in the art, for example, repeating units of Formula 1 below. .

[Formula 1]

In Formula 1, n is an integer of 1 to 5, preferably about 1 to 3, most preferably 2, m is 5 to 5000, preferably 10 to 3000.

For example, as the polyalkyleneimine-based polymer, not only a single polymer composed of the repeating unit, but also all types of copolymers such as a block copolymer or a graft copolymer may be used. In addition, the polyalkyleneimine-based polymer, as well as unmodified polymer, modified polymer, for example, by modifying the organic functional group or inorganic material such as metal, carboxyl group or epoxy group such as titanium to the repeating unit ends Alternatively, polymers in which at least a part of the repeating unit is modified with various functional groups such as vinyl may also be used. Such modified polyalkyleneimine-based polymers may be prepared or commercially available by methods known to those skilled in the art. In addition, although each of the said unmodified or modified polyalkylene imine-type polymers can also be used, it is a matter of course that a mixture thereof can also be used.

The polyalkyleneimine-based polymer improves the adhesion between the coating composition and the thermoplastic resin substrate, thereby forming a good gas barrier coating layer on the thermoplastic resin substrate, and the gas barrier coating composition, for example, a coating liquid. The gelation can be suppressed at the time of storage.

The polyalkyleneimine-based polymer may have a number average molecular weight corresponding to the number m of the repeating unit, for example, may have a number average molecular weight of 150 to 150,000, preferably a number average molecular weight of 300 to 100,000. . Polyalkyleneimine-based polymers satisfying these molecular weights further improve the adhesion of the coating composition and enable the formation of a good coating layer.

The coating composition described above also comprises a mixed solvent of lower alcohols having 1 to 5 carbon atoms and water as the medium. By adding a lower alcohol to the water, which is the basic medium, as a medium, it is possible to further improve the drying or curing rate during the formation of the coating layer, and to reduce the possibility of pinholes, thereby to better provide a gas barrier coating layer having excellent transparency. It can be formed.

In the mixed solvent, the lower alcohol may be methanol, ethanol or isopropanol, and most preferably isopropanol.

The mixed solvent may include the lower alcohol: water in a weight ratio of 1:10 to 5: 5. If the weight ratio of the lower alcohol is too small, the possibility of pinholes may increase, and the gas barrier property of the coating layer may be lowered. On the contrary, if the weight ratio of the lower alcohol is too large, the coating composition of the coating composition may deteriorate or gelation may occur when the coating liquid is stored. Can be.

On the other hand, the above-described coating composition may include the polyvinyl alcohol: polyalkyleneimine-based polymer in a weight ratio of 100: 1 to 1: 1, preferably 20: 1 to 5: 1: 1. When the ratio of the polyvinyl alcohol is excessively high, the ratio of the polyalkyleneimine-based polymer may be relatively low, thereby decreasing the adhesion between the coating composition and the thermoplastic resin substrate. On the contrary, when the ratio of polyvinyl alcohol is too low, the physical properties of the coating layer and the gas barrier film including the same, in particular, the gas barrier property such as oxygen barrier property may be lowered.

More specifically, the coating composition described above comprises 1 to 20 parts by weight of the polyvinyl alcohol and 80 to 99 parts by weight of the mixed solvent, and with respect to 100 parts by weight of the sum of the polyvinyl alcohol and the mixed solvent. It may comprise 0.3 to 10 parts by weight, preferably 0.5 to 5 parts by weight of the polyalkyleneimine-based polymer. By including each component in such a content range, physical properties such as gas barrier properties and adhesion to the resin substrate of the coating composition can be optimized, so that a coating layer exhibiting excellent gas barrier properties and transparency can be appropriately applied on the thermoplastic resin substrate. Can be formed. In particular, a pinhole may be generated during the formation of the coating layer or gelling may occur during storage of the coating composition, thereby forming a good coating layer.

On the other hand, the coating composition according to an embodiment of the present invention, in addition to each component described above may further include an additive commonly used in the gas barrier coating composition. Examples of such additives include antifoaming agents or wetting agents, and of course they may be included together.

Such antifoaming agents and wetting agents may be included in amounts of 0.001 to 5% by weight and 0.01 to 5% by weight, and preferably included in amounts of 0.01 to 2% by weight and 0.5 to 2% by weight relative to the total weight of the coating composition. Can be. The antifoaming agent can suppress the generation of bubbles or surface bubbles, etc. in the coating composition containing polyvinyl alcohol, and even if such bubbles occur, it is possible to quickly remove the air bubbles exposed to the surface of the coating composition. In addition, the wetting agent may improve the wettability of the coating composition on the resin substrate. Therefore, the formation of a better coating layer is possible by including such an antifoaming agent, a humectant, and the like.

As the antifoaming agent and the humectant, any of those known to be usable in the coating composition applied to the resin substrate may be used without any particular limitation. For example, the antifoaming agent may be commercially available as a silicone antifoaming agent, a modified silicone antifoaming agent, or a non-silicone antifoaming agent, and the like. The wetting agent may be a commercialization as a hydrocarbon wetting agent, a silicone wetting agent, or a fluorine wetting agent.

In addition, if the content of the antifoaming agent or humectant is too low, it is difficult to achieve the effect of the addition thereof, on the contrary, if the content of the antifoaming agent is excessively high, the antifoaming agent is excessively high, so that the wettability of the substrate of the coating composition decreases, or the humectant is excessively high, so that a good coating layer is obtained. Formation can be difficult.

On the other hand, the above-described coating composition may include a solid content including polyvinyl alcohol, polyalkyleneimine-based polymer and the like in a concentration of 1 to 20% by weight based on the mixed solvent. Within this solid concentration range, an optimized solid concentration can be obviously determined by those skilled in the art in consideration of coating methods of coating compositions and the like.

For example, when the coating composition is applied on a resin substrate by a gravure coating method, a coating composition having a solid content concentration of 1 to 20 wt%, preferably 5 to 15 wt% may be applied to form a good coating layer. have. At this time, if the solid content concentration is too low, the amount of the mixed solvent to be dried is too large, the process of forming the coating layer may be inefficient. In addition, when the solid content concentration is too high, the viscosity is high, so that the coating composition does not spread well on the resin substrate, so that coating is difficult and process efficiency may be very poor.

The above-described coating composition may be coated on the resin substrate by any method previously known, such as dip coating, spray coating, flow coating, roll coating, bar coating, spin coating or gravure coating. After coating on the thermoplastic resin substrate by such a coating method, it may be dried for several seconds to 30 minutes at 60 to 80 ℃ to form a gas barrier coating layer on the resin substrate. For example, when the coating composition is coated by the method of gravure coating, it may be dried for several seconds (2 to 3 seconds) to 5 to 6 minutes, preferably several seconds (2 to 3 seconds) to 1 minute, and the like. According to various coating methods, those skilled in the art can easily determine an appropriate drying time to proceed with drying.

By coating in this manner, a gas barrier coating layer can be formed on the thermoplastic resin substrate. Such a gas barrier coating layer may be satisfactorily formed on the resin substrate without actually generating pinholes or the like during the formation process, and may exhibit excellent transparency and gas barrier properties. Therefore, the gas barrier film including the resin substrate and the coating layer has an excellent gas barrier while maintaining excellent physical properties (eg, mechanical strength, gloss, wear resistance, chemical resistance, or moisture resistance, etc.) derived from the thermoplastic resin substrate itself. Since it can exhibit the property, it can be applied very preferably as a packaging material of various products, such as food.

In particular, by using the coating composition according to the embodiment of the present invention, even when the thermoplastic resin substrate is a polyolefin resin substrate or the like, it is possible to form a coating layer exhibiting excellent transparency and gas barrier properties without a separate anchor layer. Can be. Therefore, the coating layer and gas barrier film which have the outstanding characteristic are formed, without reducing the outstanding physical property of the said thermoplastic resin base material, and can be used suitably as various packaging materials.

According to another embodiment of this invention, there is provided a gas barrier film obtained from the above-described coating composition. Such gas barrier films include thermoplastic resin substrates; And a coating layer on the substrate formed from the coating composition described above. In such a gas barrier film, the coating layer may include polyvinyl alcohol and polyalkyleneimine-based polymer.

The thermoplastic resin substrate included in such a film may include any type of thermoplastic resin sheet or film including a polyester resin, a polyamide resin, or a polyolefin resin as a main component, which has been known for use in packaging materials. For example, such a thermoplastic resin base material may be a polyolefin resin film or sheet such as a polypropylene film or a polypropylene sheet such as polyethylene film, polyethylene sheet, or biaxially oriented polypropylene film; Polyester resin films or sheets such as polyethylene terephthalate film, polyethylene terephthalate sheet, polylactic acid (PLA) film or polylactic acid (PLA) sheet; Or polyamide-based resin films or sheets such as nylon films or nylon sheets. In addition, any thermoplastic resin film or sheet known to be applicable to food packaging materials or the like can be used as the thermoplastic resin substrate.

Among these various thermoplastic resin substrates, polyolefin resin substrates have excellent mechanical properties such as mechanical strength, transparency, gloss, wear resistance, chemical resistance, or moisture resistance, and have low specific gravity and unit cost. Or has been reviewed. However, due to the low gas barrier property of the polyolefin-based resin substrate, there are limitations in application to food packaging materials and the like. In particular, the coating composition previously known was difficult to form a good coating layer without a separate anchor layer, there was also a disadvantage that the anchor layer lowers the excellent physical properties of the resin substrate. However, by applying the gas barrier coating composition according to the embodiment of the present invention, it is possible to form a coating layer exhibiting excellent gas barrier properties and transparency on the polyolefin-based resin substrate without a separate anchor layer. Therefore, the gas barrier film according to another embodiment of the present invention including the polyolefin-based resin substrate and the coating layer may exhibit excellent transparency and gas barrier properties due to the coating layer while maintaining various advantages of the polyolefin-based resin substrate. It can exhibit excellent adhesion between the polyolefin-based resin substrate and the coating layer, it can be preferably applied as a food packaging material.

On the other hand, the polyvinyl alcohol and polyalkyleneimine-based polymers included in the coating layer of the gas barrier film, as described above with respect to the coating composition according to an embodiment of the present invention, polyvinyl alcohol contained in the coating layer And the content of the polyalkyleneimine-based polymer or the like is also the same as or corresponding to the content of the above-described coating composition except for the mixed solvent.

The coating layer containing these components does not form or interpose another layer, film or substrate, for example, a separate anchor layer or an adhesive layer, or the like with the thermoplastic resin substrate, and the coating layer is formed on the surface of the thermoplastic resin substrate. It may be formed directly on the thermoplastic resin substrate to abut. However, in some cases, when it is necessary to further increase the adhesion or adhesion between the thermoplastic resin substrate and the coating layer, an adhesive layer may be further formed between the thermoplastic resin substrate and the coating layer of the gas barrier film. For example, when it is necessary to further raise the adhesiveness between the polyolefin resin substrate and the coating layer, it is preferable to further form an adhesive layer therebetween.

Such an adhesive layer may be formed by using a general adhesive composition for improving the adhesion between the thermoplastic resin substrate and the coating layer, for example, conventional primers or anchor coatings that are known or commercially available before. . Such adhesive compositions may include, for example, urethane-based, acrylic-based or polyester-based resins or various other polyvinyl-based resins or polyvinyl-based copolymers as main components, depending on the composition of a known primer or anchor coating agent. (Eg, it may be included in an amount of 50% by weight or more), and may further include various additives according to other needs. Such an adhesive layer can further improve the adhesion between the thermoplastic resin substrate and the coating layer without lowering the transparency of the thermoplastic resin substrate or the coating layer.

In addition, the adhesive layer is applied to the thermoplastic resin substrate by various coating methods such as dip coating, spray coating, flow coating, roll coating, bar coating, spin coating or gravure coating, similarly to the method of forming the coating layer, It can form by drying. At this time, the gravure coating may be preferably applied as the coating method.

On the other hand, after selectively forming an adhesive layer on the thermoplastic resin substrate (or without forming a separate adhesive layer), to form a coating layer on the thermoplastic resin substrate or the adhesive layer, the method of forming the coating layer in one embodiment of the invention The coating composition according to the above is as described above. That is, the coating composition described above is applied by various coating methods such as dip coating, spray coating, flow coating, roll coating, bar coating, spin coating, or gravure coating, and then, for example, several seconds (2 to 2 ° C.) at 60 to 80 ° C. 3 seconds) to 30 minutes to form a gas barrier coating layer. More specifically, when the coating composition is coated by the method of gravure coating, it may be dried for several seconds (2 to 3 seconds) to 5 to 6 minutes, preferably several seconds (2 to 3 seconds) to 1 minute, and the like. According to various coating methods, those skilled in the art can easily determine an appropriate drying time to proceed with drying.

This coating layer may have a thickness of 0.2 to 7㎛, preferably 0.5 to 1.5㎛ in terms of excellent gas barrier properties. However, one of ordinary skill in the art can obviously adjust and apply the thickness of the coating layer in consideration of the application to which the gas barrier film including the coating layer is applied or the degree of gas barrier property required thereto.

The gas barrier film including the coating layer and the thermoplastic resin substrate as described above may be very preferably applied to a food packaging material or the like requiring oxygen barrier property. More specifically, the gas barrier film may be preferably applied as a soft packaging material for foods such as snacks, soft cakes, chocolate bars, biscuits, meat products, noodles, etc., and in addition to these foods, various product packaging materials requiring gas barrier properties It can be applied as appropriate.

As described above, according to the present invention, it is possible to form a gas barrier coating layer having excellent gas barrier property, adhesiveness and transparency on various thermoplastic resin substrates made of polyester resin, polyolefin resin or polyamide resin. . Accordingly, since the gas barrier film can be provided by forming a gas barrier coating layer having excellent physical properties on various thermoplastic resin substrates, such a gas barrier film can be applied very preferably as a food packaging material.

Hereinafter, the operation and effects of the invention will be described in more detail with reference to specific examples of the invention. However, these embodiments are only presented as an example of the invention, whereby the scope of the invention is not determined.

Examples 1 to 6: Preparation of Gas Barrier Films Comprising Biaxially Stretched Polypropylene Films as Thermoplastic Resin Substrate

Unmodified polyvinyl alcohol (PVA) having a number average molecular weight of about 20,000 and a saponification degree of 99%, polyethyleneimine-based polymer as a polyalkyleneimine-based polymer, and a mixed solvent of isopropanol (IPA) and water The gas barrier coating compositions of Examples 1 to 6 were prepared. In this case, as the polyethyleneimine-based polymer, a titanium-modified polyethyleneimine in which titanium is bonded to the terminal and modified, a number average molecular weight of about 5000 was used.

First, according to the composition shown in Table 1, 5 or 10 g of polyvinyl alcohol is dissolved in 95 or 90 g of a mixed solvent in which isopropanol and water are mixed at a weight ratio of 3: 7, so that the concentration of polyvinyl alcohol is 5 or 10% by weight. A solution was obtained. The gas barrier coating compositions of Examples 1 to 6 were prepared by mixing and modifying titanium-modified polyethyleneimine by the weight shown in Table 1 to 100 g of this solution. The coating composition was gravure coated on a biaxially stretched polypropylene (OPP) film (substrate) and dried at 80 ° C. for 1 minute to prepare gas barrier films of Examples 1 to 6.

Comparative Examples 1 and 2: Preparation of Gas Barrier Film Comprising Biaxially Stretched Polypropylene Film as Thermoplastic Resin Substrate

Unmodified polyvinyl alcohol (PVA) having a number average molecular weight of about 20,000 and a saponification degree of 99%, aminopropyltriethoxysilane (APTES) as an amine silane, and a mixed solvent of isopropanol (IPA) and water The gas barrier coating compositions of Comparative Examples 1 and 2 were prepared by the method.

First, 5 or 10 g of polyvinyl alcohol was dissolved in 95 or 90 g of a mixed solvent in which isopropanol and water were mixed at a weight ratio of 3: 7 to obtain a solution having a polyvinyl alcohol concentration of 5 or 10% by weight. The gas barrier coating compositions of Comparative Examples 1 and 2 were prepared by mixing and stirring aminopropyltriethoxysilane (APTES) by the weight shown in Table 1 to 100 g of this solution. The coating composition was gravure coated on a biaxially stretched polypropylene (OPP) film (substrate) and dried at 80 ° C. for 1 minute to prepare gas barrier films of Comparative Examples 1 and 2.

The physical properties of the gas barrier films of Examples 1 to 6 and Comparative Examples 1 and 2 obtained as described above were measured by the following method, and are shown in Table 1 below.

(1) transparency

The film was evaluated by comparing the film before and after coating layer formation with the naked eye and a haze meter. (Circle), the case where the value of the light transmittance measured by the haze meter after the coating layer is formed in more than 90% was evaluated as X, the case in which △, less than 80% appeared when 80% or more and less than 90%.

(2) gas barrier properties

While maintaining each gas barrier film in a dry room temperature atmosphere, gas barrier property was evaluated by the method of measuring oxygen permeability using the oxygen permeability measuring apparatus ("OX-TRAN 2/61" by MOCON).

(3) adhesion

It evaluated using the resin base material and the test tape adhesion test tape. The case where the dried and cured coating layer transitioned to the tape was evaluated as X, otherwise as O. In the case of the X, that is, when the transition to the tape to the coating layer, the adhesive strength between the resin substrate and the coating layer was 100 gf / 15 mm or less, which was evaluated as poor adhesion.

 (4) film thickness

The thickness of the dried and cured coating layer was measured using a scanning electron microscope. These physical property evaluation results are summarized in Table 1 below.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 article
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(g) PVA 5 10 5 5 5 10 10 10 Titanium modified polyethyleneimine 0 0 0.5 One 2 0.5 One 2 Aminopropyltriethoxysilane (APTES) 2 2 0 0 0 0 0 0 solvent
(IPA / water) 95
(3/7) 90
(3/7) 95
(3/7) 95
(3/7) 95
(3/7) 90
(3/7) 90
(3/7) 90
(3/7) Thermoplastic Base OPP OPP OPP OPP OPP OPP OPP OPP Evaluation
end Film thickness (㎛) To 1 ~ 2 To 1 To 1 To 1 ~ 2 ~ 2 ~ 2 Transparency O O O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 <2 <2 Adhesion X X O O O O O O

In Table 1, OPP represents a biaxially stretched polypropylene film.

Referring to Examples 1 to 6 of Table 1, when forming a coating layer on a thermoplastic resin substrate, in particular, a polyolefin resin substrate using a coating composition comprising a polyvinyl alcohol and a polyalkyleneimine-based polymer, excellent gas It is confirmed that a coating layer exhibiting barrier property and transparency can be well formed on the resin substrate. In particular, it is confirmed that such a gas barrier coating layer can be formed on the resin substrate with good adhesion to a thin thickness even without a separate adhesive layer.

Therefore, the gas barrier films of Examples 1 to 6 including such a coating layer may be very preferably applied to various packaging materials.

In contrast, the coating compositions of Comparative Examples 1 and 2 and gas barrier films formed therefrom which do not include polyalkyleneimine-based polymers but instead include amine-based silane compounds such as aminopropyltriethoxysilane (APTES) It was confirmed that the adhesion between the thermoplastic resin substrate and the coating layer was poor. For this reason, the coating compositions of Comparative Examples 1 and 2 are likely to be difficult to apply to the polyolefin-based resin substrate.

Examples 7 to 12 Preparation of Gas Barrier Films Comprising Polyethylene Terephthalate Films as Thermoplastic Resin Substrate

The coating composition of Examples 7 to 12 was prepared according to the composition of Table 2 in the same manner as in Examples 1 to 6. The coating composition was gravure coated on a polyethylene terephthalate film (substrate) and dried at 80 ° C. for 1 minute to prepare gas barrier films of Examples 7 to 12.

The physical properties of the gas barrier films of Examples 7 to 12 obtained as described above were measured by the same method as Examples 1 to 6, and are shown in Table 2 below.

Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 article
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(g) PVA 5 5 5 10 10 10 Titanium modified polyethyleneimine 0.5 One 2 0.5 One 2 Aminopropyltriethoxysilane (APTES) 0 0 0 0 0 0 solvent
(IPA / water) 95
(3/7) 95
(3/7) 95
(3/7) 90
(3/7) 90
(3/7) 90
(3/7) Thermoplastic Base PET PET PET PET PET PET Evaluation
end Film thickness (㎛) To 1 To 1 To 1 ~ 2 ~ 2 ~ 2 Transparency O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 Adhesion O O O O O O

* In Table 2, PET represents a polyethylene terephthalate film.

Referring to Examples 7 to 12 of Table 2, when forming a coating layer on a polyester-based resin substrate using a coating composition comprising a polyvinyl alcohol and a polyalkyleneimine-based polymer, excellent gas barrier properties and transparency It is confirmed that the coating layer shown can be satisfactorily formed on the resin substrate. In particular, it is confirmed that such a gas barrier coating layer can be formed on the resin substrate with good adhesion to a thin thickness even without a separate adhesive layer.

Therefore, the gas barrier films of Examples 7 to 12 including such a coating layer may be very preferably applied to various packaging materials.

Examples 13 to 18 Preparation of Gas Barrier Films Comprising Nylon Films as Thermoplastic Resin Substrate

The coating composition of Examples 13 to 18 was prepared according to the composition of Table 3 in the same manner as in Examples 1 to 6. The coating composition was gravure coated on a polyethylene terephthalate film (substrate) and dried at 80 ° C. for 1 minute to prepare gas barrier films of Examples 13 to 18.

The physical properties of the gas barrier films of Examples 13 to 18 obtained as described above were measured by the same method as Examples 1 to 6, and are shown in Table 3 below.

Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 article
castle
(g) PVA 5 5 5 10 10 10 Titanium modified polyethyleneimine 0.5 One 2 0.5 One 2 Aminopropyltriethoxysilane (APTES) 0 0 0 0 0 0 solvent
(IPA / water) 95
(3/7) 95
(3/7) 95
(3/7) 90
(3/7) 90
(3/7) 90
(3/7) Thermoplastic Base ON ON ON ON ON ON Evaluation
end Film thickness (㎛) To 1 To 1 To 1 ~ 2 ~ 2 ~ 2 Transparency O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 Adhesion O O O O O O

In Table 3, ON indicates biaxially stretched nylon film.

Referring to Examples 13 to 18 of Table 3, when forming a coating layer on a polyamide-based resin substrate such as a nylon film using a coating composition comprising a polyvinyl alcohol and a polyalkyleneimine-based polymer, excellent gas barrier It is confirmed that a coating layer exhibiting properties and transparency can be satisfactorily formed on the resin substrate. In particular, it is confirmed that such a gas barrier coating layer can be formed on the resin substrate with good adhesion to a thin thickness even without a separate adhesive layer.

Therefore, the gas barrier films of Examples 13 to 18 including such a coating layer may be very preferably applied to various packaging materials.

Claims (21)

Polyvinyl alcohol; Polyalkyleneimine-based polymers; And a mixed solvent of a lower alcohol having 1 to 5 carbon atoms and water.
The gas barrier coating composition of claim 1, wherein the polyvinyl alcohol has a saponification degree of 60% or more and a polymerization degree of 100 to 5000.
The gas barrier coating composition of claim 1, wherein the polyvinyl alcohol has a number average molecular weight of 5000 to 300000.
The gas barrier coating composition of claim 1, wherein the polyvinyl alcohol comprises unmodified polyvinyl alcohol, modified polyvinyl alcohol, or a mixture thereof.
The gas barrier coating composition of claim 1, wherein the polyalkyleneimine-based polymer comprises a repeating unit represented by Formula 1 below:
[Formula 1]

In Formula 1 n is an integer of 1 to 3, m is 5 to 5000.
The gas barrier coating composition of claim 1, wherein the polyalkyleneimine-based polymer has a number average molecular weight of 150 to 150,000.
The gas barrier coating composition of claim 1, wherein the polyalkyleneimine-based polymer comprises an unmodified polyalkyleneimine-based polymer, a modified polyalkyleneimine-based polymer, or a mixture thereof.
8. The gas barrier coating composition of claim 7, wherein the polyalkyleneimine-based polymer comprises a titanium-modified polyalkyleneimine-based polymer.
The gas barrier coating composition of claim 1, wherein the mixed solvent comprises the lower alcohol: water in a weight ratio of 1:10 to 5: 5.
The gas barrier coating composition of claim 1, wherein the polyvinyl alcohol: polyalkyleneimine-based polymer is included in a weight ratio of 100: 1 to 1: 1.
According to claim 1, 1 to 20 parts by weight of the polyvinyl alcohol; 80 to 99 parts by weight of the mixed solvent; And 0.3 to 10 parts by weight of the polyalkyleneimine-based polymer based on 100 parts by weight of the polyvinyl alcohol and the mixed solvent.
The gas barrier coating composition of claim 1, further comprising 0.001 to 5% by weight antifoaming agent, based on the weight of the total coating composition.
The gas barrier coating composition of claim 1, further comprising 0.01 to 5% by weight of a wetting agent relative to the total weight of the coating composition.
The gas barrier coating composition according to claim 1, wherein the solid concentration is 1 to 20% by weight.
Thermoplastic resin substrate; And a coating layer on the substrate formed from the coating composition of any one of claims 1 to 14.
Thermoplastic resin substrate; And a coating layer on the substrate including polyvinyl alcohol and polyalkyleneimine-based polymer.
The gas barrier film according to claim 15 or 16, wherein the thermoplastic resin substrate is a polyester resin substrate, a polyamide resin substrate, or a polyolefin resin substrate.
18. The method of claim 17, wherein the thermoplastic resin substrate is polyethylene film, polyethylene sheet, biaxially oriented polypropylene film (Oriented Polypropylene Film), polypropylene sheet, polyethylene terephthalate film, polyethylene terephthalate sheet, polylactic acid (PLA; polylactic acid) A gas barrier film comprising a film or a polylactic acid (PLA) sheet, a nylon film or a nylon sheet.
The gas barrier film according to claim 15 or 16, further comprising an adhesive layer between the thermoplastic resin substrate and the coating layer.
The gas barrier film of claim 15, wherein the coating layer has a thickness of 0.2 to 7 μm.
The gas barrier film according to claim 15 or 16, which is used as a packaging material.