KR20110076719A - Gas barrier coating composition and gas barrier film - Google Patents

Abstract

PURPOSE: A gas barrier coating composition is provided to form a gas barrier coating layer with excellent gas-barrier property, adhesion and transparency on various thermoplastic resin substrates. CONSTITUTION: A gas barrier coating composition comprises polyvinylalcohol, chlorinated polyolefin, and a mixed solvent of C1-5 lower alcohol with water. The polyvinyl alcohol has a saponification degree more than 50% and a polymerization degree of 100~5000 and has the number average molecular weight of 5000~300000. The polyvinyl alcohol comprises unmodified-polyvinyl alcohol, modified polyvinyl alcohol or their mixture. The chlorinated polyolefin comprises 5-30 weight% of chlorine and has a number average molecular weight of 20000-120000.

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.

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; Chlorinated polyolefins; 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 a coating layer formed on the substrate and comprising a polyvinyl alcohol and a chlorinated polyolefin.

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 "chlorinated polyolefin" refers to any polymer in which at least some of the hydrogen of a polyolefin repeat unit is replaced with chlorine. Such polymers can encompass homopolymers of any form as well as homopolymers consisting of “chlorinated polyolefin” repeat units, including chlorinated polyolefin emulsions, (partial) hydrolysates, (partial) condensates thereof or their Polymers of any form may be encompassed, including mixtures such as "chlorine substituted polyolefin" repeat units. In addition, the category of "chlorinated polyolefin" may include not only polymers not modified, but also polymers modified with acrylic acid or maleic anhydride.

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. Such a "thermoplastic resin base" category includes a polyester resin, a polyamide resin, a polyolefin resin, and the like, and may also include a thermoplastic resin sheet or film that is stretched, unstretched, or has any other form.

In addition, in this specification, a certain layer is "directly formed" on the substrate, so that another layer, film, or substrate is not formed or interposed separately between the substrate and the layer, and the layer is formed on the surface of the substrate. It means that the layer is formed on the substrate so that it is in direct contact. 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; Chlorinated polyolefins; 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, a coating layer having excellent adhesiveness while showing excellent gas barrier property and transparency on a thermoplastic resin substrate using a coating composition comprising three components described above, in particular, polyvinyl alcohol and chlorinated polyolefin, is excellent. It was found that can be formed.

This shows that the polyvinyl alcohol exhibits excellent gas barrier properties (for example, oxygen barrier property), and the chlorinated polyolefin improves the adhesion between the coating composition and the thermoplastic resin substrate to enable formation of a good coating layer without pinholes or the like. It seems to be. In addition, the chlorinated polyolefin 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 limited to the material of the thermoplastic resin substrate. The gas barrier film applicable to various packaging materials can be obtained universally.

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 degree of saponification of 50% or more, preferably 70% or more, more preferably 70 to 99.9%, and may have a degree of polymerization 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 chlorinated polyolefin to improve the adhesion to the resin substrate and to form a good gas barrier coating layer excellent in transparency. Such chlorinated polyolefins include all types of polymers consisting of “chlorinated polyolefin” repeat units, such as homopolymers, copolymers, chlorinated polyolefin emulsions, (partial) hydrolysates, (partial) condensates or mixtures thereof. It is as described above that any type of polymer, such as can be used. In addition, as the chlorinated polyolefin, not only a polymer that is not modified, but also a polymer whose end group is modified with acrylic acid or maleic anhydride may be used.

This chlorinated polyolefin improves the adhesion between the coating composition and the thermoplastic resin substrate, thereby making it possible to form a good gas barrier coating layer on the thermoplastic resin substrate, and when storing the gas barrier coating composition, for example, a coating liquid. Gelation can be suppressed.

The chlorinated polyolefin may comprise 5 to 30% by weight, 15 to 25% by weight of chlorine. In addition, the chlorinated polyolefin may have a number average molecular weight of 20000 to 120000, preferably 50000 to 100000. Chlorinated polyolefins that meet the chlorine substitution content and molecular weight in these molecules further improve the adhesion of the coating composition and allow for the formation of good coating layers.

In addition, the chlorinated polyolefin may be an unmodified chlorinated polyolefin, an acrylic acid modified chlorinated polyolefin or maleic anhydride modified chlorinated polyolefin, or a mixture of two or more selected from them.

In this case, as the unmodified chlorinated polyolefin, a number average molecular weight is 40000 to 90000, and a chlorine content substituted in the molecule is preferably 14 to 20% by weight. As the acrylic acid-modified chlorinated polyolefin, an acrylic acid: chlorinated polyolefin in the chlorinated polyolefin molecule may have a weight ratio of 40:60 to 60:40, and the number average molecular weight is 40000 to 90000, and chlorine substituted in the molecule It is preferable to use a content of 20 to 26% by weight. As the maleic anhydride-modified chlorinated polyolefin, maleic anhydride content in a molecule may be used in an amount of 1 to 5 wt%, a number average molecular weight is 40000 to 90000, and a chlorine content substituted in the molecule is 19 to 25 wt%. % Can be used preferably. By using such unmodified or modified chlorinated polyolefin, a coating layer excellent in transparency and gas barrier property can be better formed on the thermoplastic resin substrate.

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 this mixed solvent, the lower alcohol may be methanol, ethanol or isopropanol.

The mixed solvent may include the lower alcohol: water in a weight ratio of 1: 9 to 4: 6. 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: chlorinated polyolefin in a weight ratio of 20: 1 to 1: 2, preferably 5: 1 to 1: 1. When the ratio of the polyvinyl alcohol is too high, the proportion of the chlorinated polyolefin 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 2 to 20 parts by weight of the polyvinyl alcohol and 80 to 98 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 0.1 to 5 parts by weight, preferably 1 to 5 parts by weight of chlorinated polyolefin. 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.

Meanwhile, the coating composition according to an embodiment of the present invention may further include 0.005 to 2 wt%, preferably 0.05 to 0.5 wt% of an antifoaming agent, in addition to each component described above. Such antifoaming agent can suppress generation of bubbles, surface bubbles, etc. in the coating composition containing polyvinyl alcohol, and can be removed even if such bubbles are generated. Therefore, the formation of a better coating layer is possible by including such an antifoaming agent.

As the antifoaming agent, any one known to be usable in the coating composition applied to the resin substrate may be used without particular limitation, and for example, a silicone antifoaming agent, a modified silicone antifoaming agent, or a non-silicone antifoaming agent may be used.

In addition, when the content of the antifoaming agent is too low to less than 0.005% by weight, it is difficult to obtain the effect of the addition, if the content is too high, the wettability to the substrate of the coating composition may occur.

On the other hand, the above-described coating composition may include a solid content including polyvinyl alcohol, chlorinated polyolefin 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 onto the resin substrate by a gravure coating method, a coating composition having a solid content concentration of 5 to 15 wt%, preferably 5 to 13 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.

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.

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 formed on the substrate and including polyvinyl alcohol and chlorinated polyolefin.

The thermoplastic resin substrate included in such a film may include all types of thermoplastic resin sheets or films containing polyester-based resins, polyamide-based resins, or polyolefin-based resins known in the past as usable 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. 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 resin substrate. Therefore, as the above-described coating composition is applied, the gas barrier film according to another embodiment of the present invention including the polyolefin-based resin substrate and the coating layer is excellent due to the coating layer while maintaining various advantages of the polyolefin-based resin substrate. Transparency and gas barrier properties can be exhibited, and excellent adhesion between the polyolefin-based resin substrate and the coating layer can be exhibited, and thus can be preferably applied to food packaging materials.

On the other hand, for the polyvinyl alcohol and chlorinated polyolefin 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 invention, polyvinyl alcohol and chlorinated polyolefin, etc. included in the coating layer The content of also corresponds to the content of the above-described coating composition except for the mixed solvent.

A coating layer comprising these components can be formed directly on the thermoplastic resin substrate such that the coating layer abuts on the surface of the thermoplastic resin substrate without forming or interposing another layer, film or substrate between the thermoplastic resin substrate. have. 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, at 60 to 80 ° C. for 5 to 30 minutes. It may be dried to form a gas barrier coating layer.

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 base material as described above may be very preferably applied to food packaging materials and the like requiring oxygen barrier properties. 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 excellent in 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 20 Preparation of Gas Barrier Films Comprising Biaxially Stretched Polypropylene Films as Thermoplastic Resin Substrate

Unmodified polyvinyl alcohol (PVA), chlorinated polyolefin, and a mixed solvent of isopropanol (IPA) and water having a number average molecular weight of about 20000 and a saponification degree of 99% were prepared by the following methods in Examples 1 to 20 and Comparative Examples. Gas barrier coating compositions were prepared. In this case, the following materials were used as the chlorinated polyolefin:

 (1) unmodified chlorinated polyolefin (CPO): having a number average molecular weight of about 60000 and a chlorine content substituted in the molecule of 16-18 wt%;

(2) Acrylic acid modified chlorinated polyolefin (Ac-CPO): number average molecular weight is about 60000, chlorine content substituted in the molecule is 22 to 24% by weight, weight ratio of acrylic acid: chlorinated polyolefin in the chlorinated polyolefin molecule = 40: 60

(3) maleic anhydride modified chlorinated polyolefin (MAH-CPO): having a number average molecular weight of about 60000 and a chlorine content substituted in the molecule of 19 to 20% by weight; Maleic anhydride content in the molecule is about 2% by weight

 First, polyvinyl alcohol was dissolved in a mixed solvent in which isopropanol and water were mixed at a weight ratio of 40:50 to obtain a solution having a polyvinyl alcohol concentration of 5, 7 or 10% by weight. The gas barrier coating compositions of Examples 1 to 20 were prepared by mixing and stirring unmodified or modified chlorinated polyolefin by the weight shown in Tables 1 or 2 below to 100 g of this solution.

On the other hand, the adhesive composition comprising a polyurethane resin having a solid content concentration of 8% by weight and a methyl ethyl ketone solvent is coated on a 20 탆 thick biaxially oriented polypropylene film by gravure coating, and then dried and cured under a condition of 80 ° C. (Primer layer) was formed.

Thereafter, the gas barrier coating composition obtained above was coated on the adhesive layer by a gravure coating method, and then hot air at 80 ° C. was applied to the surface of the coating layer for several seconds (2 to 3 seconds) to 1 minute to be dried and cured. In this way, the gas barrier films of Examples 1 to 20 having a coating layer formed on the film were obtained.

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

Gas barrier coating compositions and gas barrier films of Comparative Examples 1 and 2 were obtained in the same manner as in Examples 1 to 20, except that no chlorinated polyolefin was used. However, the gas barrier film of Comparative Example 1 was obtained by directly forming a coating layer on a biaxially stretched polypropylene film having a thickness of 20 μm without forming an adhesive layer.

Specific compositions of the gas barrier coating compositions of Comparative Examples 1 and 2 were as described in Table 1 below.

The physical properties of the gas barrier films of Examples 1 to 20 and Comparative Examples 1 and 2 obtained as described above were measured by the following methods and described in Tables 1 and 2 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. The case where the value measured by the haze meter is 85% or more and the case where 75% or more and 85% or less are shown as Δ and 75% or less is evaluated as X.

(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.

(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 or 2 below.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 article
castle
(g) PVA 5 5 5 5 5 7 7 7 10 10 10 5 CPO 0 0 2 One 0 2 One 0 2 One 0 One Ac-CPO 0 0 0 One 2 0 One 2 0 One 2 One solvent
(IPA / water) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 93
(40/50) 93
(40/50) 93
(40/50) 90
(40/50) 90
(40/50) 90
(40/50) 95
(40/50) Adhesive layer X O O O O O O O O O O X Thermoplastic Base OPP OPP OPP OPP OPP OPP OPP OPP OPP OPP OPP OPP Evaluation
end Film thickness (㎛) To 1 To 1 To 1 To 1 To 1 ~ 1.5 ~ 1.5 ~ 1.5 ~ 2 ~ 2 ~ 2 To 1 Transparency O O O O O O O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 <2 <2 <1 <1 <1 <2 Adhesion X X O O O O O O O O O O

Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 Example 20 article
castle
(g) PVA 5 5 5 7 7 7 10 10 10 5 CPO 2 One 0 2 One 0 2 One 0 One MAH-CPO 0 One 2 0 One 2 0 One 2 One solvent
(IPA / water) 95
(40/50) 95
(40/50) 95
(40/50) 93
(40/50) 93
(40/50) 93
(40/50) 90
(40/50) 90
(40/50) 90
(40/50) 95
(40/50) Adhesive layer O O O O O O O O O X Thermoplastic Base OPP OPP OPP OPP OPP OPP OPP OPP OPP OPP Evaluation
end Film thickness (㎛) To 1 To 1 To 1 ~ 1.5 ~ 1.5 ~ 1.5 ~ 2 ~ 2 ~ 2 To 1 Transparency O O O O O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 <1 <1 <1 <2 Adhesion O O O O O O O O O O

* In Tables 1 and 2 above, OPP represents a biaxially stretched polypropylene film.

Referring to Tables 1 and 2 above, when a coating layer is formed on a thermoplastic resin substrate, particularly a polyolefin resin substrate using a coating composition including polyvinyl alcohol and chlorinated polyolefin, the coating layer exhibiting excellent gas barrier properties and transparency is It is confirmed that it can be formed satisfactorily on a resin base material. 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, as well as when there is an adhesive layer as well as when there is no separate adhesive layer (see Examples 10 and 20).

Therefore, the gas barrier films of Examples 1 to 20 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 the gas barrier films formed therefrom which do not include chlorinated polyolefins are poor in adhesion between the thermoplastic resin substrate and the coating layer, and thus may be difficult to be applied to packaging materials.

Examples 21 to 44, Comparative Examples 3 and 4: Preparation of gas barrier film comprising polyethylene terephthalate film as thermoplastic resin substrate

To prepare a gas barrier coating composition according to the composition of Tables 3 to 5, and the same method as in Examples 1 to 20, Comparative Examples 1 and 2 except for using a polyethylene terephthalate film having a thickness of 12㎛ as a thermoplastic resin substrate Thus, the gas barrier coating compositions and gas barrier films of Examples 21 to 44 and Comparative Examples 3 and 4 were obtained.

However, the gas barrier films of Examples 24 to 32, 36 to 44 and Comparative Example 3 were obtained by directly forming a coating layer on a polyethylene terephthalate film having a thickness of 12 μm without forming an adhesive layer.

The overall physical properties of the gas barrier films of Examples 21 to 44 and Comparative Examples 3 and 4 obtained as described above were measured by the same method as Examples 1 to 20 and Comparative Examples 1 and 2, and are shown in Tables 3 to 5 below.

Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Example 27 Example 28 Example 29 Example 30 Example 31 Example 32 article
castle
(g) PVA 5 5 5 5 5 5 7 7 7 10 10 10 CPO 2 One 0 2 One 0 2 One 0 2 One 0 Ac-CPO 0 One 2 0 One 2 0 One 2 0 One 2 solvent
(IPA / water) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 93
(40/50) 93
(40/50) 93
(40/50) 90
(40/50) 90
(40/50) 90
(40/50) Adhesive layer O O O X X X X X X X X X Thermoplastic Base PET PET PET PET PET PET PET PET PET PET PET PET Evaluation
end Thickness
(Μm) To 1 To 1 To 1 To 1 To 1 To 1 ~ 1.5 ~ 1.5 ~ 1.5 ~ 2 ~ 2 ~ 2 Transparency O O O O O O O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 <1 <1 <1 <1 <1 <1 Adhesion O O O O O O O O O O O O

Example 33 Example 34 Example 35 Example 36 Example 37 Example 38 Example 39 Example 40 Example 41 Example 42 Example 43 Example 44 article
castle
(g) PVA 5 5 5 5 5 5 7 7 7 10 10 10 CPO 2 One 0 2 One 0 2 One 0 2 One 0 MAH-CPO 0 One 2 0 One 2 0 One 2 0 One 2 solvent
(IPA / water) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 93
(40/50) 93
(40/50) 93
(40/50) 90
(40/50) 90
(40/50) 90
(40/50) Adhesive layer O O O X X X X X X X X X Thermoplastic Base PET PET PET PET PET PET PET PET PET PET PET PET Evaluation
end Thickness
(Μm) To 1 To 1 To 1 To 1 To 1 To 1 ~ 1.5 ~ 1.5 ~ 1.5 ~ 2 ~ 2 ~ 2 Transparency O O O O O O O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 <1 <1 <1 <1 <1 <1 Adhesion O O O O O O O O O O O O

Comparative Example 3 Comparative Example 4 article
castle
(g) PVA 5 5 CPO 0 0 Ac-CPO
(Or MAH-CPO) 0 0 solvent
(IPA / water) 95
(40/50) 95
(40/50) Adhesive layer X O Thermoplastic Base PET PET Evaluation
end Thickness
(Μm) To 1 To 1 Transparency O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 Adhesion X X

* In Tables 3 to 5, PET represents a polyethylene terephthalate film.

Examples 45-68, Comparative Examples 5 and 6: Preparation of Gas Barrier Film Comprising Nylon Film as Thermoplastic Resin Substrate

To prepare a gas barrier coating composition according to the composition of Tables 6 to 8, and carried out in the same manner as in Examples 1 to 20, Comparative Examples 1 and 2, except that a nylon film having a thickness of 20 ㎛ as a thermoplastic resin substrate was used. The gas barrier coating compositions and gas barrier films of Examples 45 to 68, Comparative Examples 5 and 6 were obtained.

However, the gas barrier films of Examples 48 to 56, 60 to 68 and Comparative Example 5 were obtained by directly forming a coating layer on a nylon film having a thickness of 20 μm without forming an adhesive layer.

The physical properties of the gas barrier films of Examples 45 to 68 and Comparative Examples 5 and 6 obtained as described above were measured in the same manner as Examples 1 to 20, Comparative Examples 1 and 2, and are shown in Tables 6 to 8 below.

Example 45 Example 46 Example 47 Example 48 Example 49 Example 50 Example 51 Example 52 Example 53 Example 54 Example 55 Example 56 article
castle
(g) PVA 5 5 5 5 5 5 7 7 7 10 10 10 CPO 2 One 0 2 One 0 2 One 0 2 One 0 Ac-CPO 0 One 2 0 One 2 0 One 2 0 One 2 solvent
(IPA / water) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 93
(40/50) 93
(40/50) 93
(40/50) 90
(40/50) 90
(40/50) 90
(40/50) Adhesive layer O O O X X X X X X X X X Thermoplastic Base Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Evaluation
end Thickness
(Μm) To 1 To 1 To 1 To 1 To 1 To 1 ~ 1.5 ~ 1.5 ~ 1.5 ~ 2 ~ 2 ~ 2 Transparency O O O O O O O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 <1 <1 <1 <1 <1 <1 Adhesion O O O O O O O O O O O O

Example 57 Example 58 Example 59 Example 60 Example 61 Example 62 Example 63 Example 64 Example 65 Example 66 Example 67 Example 68 article
castle
(g) PVA 5 5 5 5 5 5 7 7 7 10 10 10 CPO 2 One 0 2 One 0 2 One 0 2 One 0 MAH-CPO 0 One 2 0 One 2 0 One 2 0 One 2 solvent
(IPA / water) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 95
(40/50) 93
(40/50) 93
(40/50) 93
(40/50) 90
(40/50) 90
(40/50) 90
(40/50) Adhesive layer O O O X X X X X X X X X Thermoplastic Base Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Nylon film Evaluation
end Thickness
(Μm) To 1 To 1 To 1 To 1 To 1 To 1 ~ 1.5 ~ 1.5 ~ 1.5 ~ 2 ~ 2 ~ 2 Transparency O O O O O O O O O O O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 <2 <2 <2 <2 <2 <2 <2 <1 <1 <1 Adhesion O O O O O O O O O O O O

Comparative Example 5 Comparative Example 6 article
castle
(g) PVA 5 5 CPO 0 0 Ac-CPO
(Or MAH-CPO) 0 0 solvent
(IPA / water) 95
(40/50) 95
(40/50) Adhesive layer X O Thermoplastic Base Nylon film Nylon film Evaluation
end Thickness
(Μm) To 1 To 1 Transparency O O Gas barrier properties
(cc / m ² .atm.day) <2 <2 Adhesion X X

Referring to Tables 3, 4, 6 and 7, in the case of using the coating composition including the polyvinyl alcohol and the chlorinated polyolefin of the embodiment, a thermoplastic resin substrate such as a polyethylene terephthalate film or a nylon film (that is, a polyester resin substrate) Or a polyamide-based resin substrate), it is confirmed that a coating layer exhibiting excellent gas barrier properties and transparency can be satisfactorily formed. 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.

Therefore, the gas barrier films of Examples 21 to 68 including such a coating layer may be very preferably applied to various packaging materials.

On the contrary, referring to Tables 5 and 8, the coating compositions of Comparative Examples 3 to 6, which do not contain chlorinated polyolefins, and the gas barrier films formed therefrom are poor in adhesion between the thermoplastic resin substrate and the coating layer, and thus are difficult to be applied to packaging materials. Seems to be.

Claims (20)

Polyvinyl alcohol; Chlorinated polyolefins; 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 degree of saponification of 50% or more and a degree of polymerization 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 chlorinated polyolefin comprises 5 to 30 weight percent chlorine. The gas barrier coating composition of claim 1, wherein the chlorinated polyolefin has a number average molecular weight of 20000 to 120000.
The gas barrier coating composition of claim 1, wherein the chlorinated polyolefin comprises one or more selected from the group consisting of unmodified chlorinated polyolefins, acrylic acid modified chlorinated polyolefins and maleic anhydride modified chlorinated polyolefins.
The gas barrier coating composition of claim 1, wherein the mixed solvent comprises the lower alcohol: water in a weight ratio of 1: 9 to 4: 6.
The gas barrier coating composition of claim 1, wherein the polyvinyl alcohol: chlorinated polyolefin is included in a weight ratio of 20: 1 to 1: 2.
According to claim 1, 2 to 20 parts by weight of the polyvinyl alcohol; 80 to 98 parts by weight of the mixed solvent; And 0.1 to 5 parts by weight of chlorinated polyolefin based on 100 parts by weight of the polyvinyl alcohol and the mixed solvent.
The gas barrier coating composition of claim 1, further comprising 0.005 to 2% by weight of an antifoaming agent of the total 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 formed on the substrate using the coating composition of any one of claims 1 to 12.
Thermoplastic resin substrate; And a coating layer formed on the substrate and comprising a polyvinyl alcohol and a chlorinated polyolefin.
The gas barrier film according to claim 13 or 14, wherein the thermoplastic resin substrate is a polyester resin substrate, a polyamide resin substrate, or a polyolefin resin substrate.
The method of claim 15, 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 ) Or a gas barrier film comprising a polylactic acid (PLA) sheet, a nylon film or a nylon sheet.
The gas barrier film according to claim 13 or 14, further comprising an adhesive layer between the thermoplastic resin substrate and the coating layer.
The gas barrier film of claim 17, wherein the adhesive layer comprises a polyurethane resin, a polyacrylic resin, or a polyamide resin.
The gas barrier film of claim 13, wherein the coating layer has a thickness of 0.2 to 7 μm.
The gas barrier film according to claim 13 or 14, which is used as a packaging material.