JP2005349769A - Laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film which can effectively prevent the erosion of the barrier layer even if an aqueous coating agent (aqueous heat seal agent) is applied, in which the barrier layer is highly adherent to the base material film, and which has high gas barrier properties (or flavor preserving property). <P>SOLUTION: The laminated film is composed of the base material film, the barrier layer formed on at least one surface of this base material film, and the heat seal layer formed on this barrier layer. The barrier layer is constituted by a water-soluble polymer compound and a crosslinking agent, and the heat seal layer is directly formed on the barrier layer by way of the aqueous coating agent. The barrier layer can be constituted by a vinyl alcohol polymer having a carbonyl group, a compound having a plurality of hydrazino groups, and an inorganic layered compound. The compound having a plurality of hydrazino groups can be a polycarboxylic acid polyhydrazide compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminated film that is excellent in barrier properties (or aroma retaining properties) such as water and oxygen and is useful as a packaging film for packaging articles.

  As a packaging film for packaging an article, a laminated film having a base film, a barrier layer having a gas barrier property (barrier film, coating layer), and a heat seal layer is known. For example, in JP-A-8-80964 (Patent Document 1), a thin film layer (barrier film) made of silicon oxide and metal oxide is formed on one side or both sides of a plastic film by a vacuum thin film forming technique. An overlapping laminate is disclosed which is composed of a sealing layer provided on one or both sides of a barrier film. However, since the laminate of this document uses a metal thin film, a crack or the like is generated in the thin film layer during use, and there is a risk that the barrier properties (water vapor barrier properties, etc.) may deteriorate.

  A laminated film in which a barrier layer is formed of a resin has also been proposed. For example, a film obtained by coating a base film such as a biaxially stretched polypropylene film with a chlorine resin such as vinylidene chloride is known. Since such vinylidene chloride resin has heat sealability, a packaging film can be formed without forming a heat seal layer on the film. However, since a film using such a chlorine-based resin may contaminate the environment when it is disposed as combustible waste, a non-chlorine-based resin film has been studied.

  Therefore, as a film using a non-chlorine resin, JP-A-11-333967 (Patent Document 2) is provided with a base film, one surface of the base film, an inorganic layered compound and a resin. There is disclosed an overlap film composed of a barrier layer containing a heat seal layer provided on the barrier layer and formed by application of a heat sealant. In this document, in order to improve the adhesion between the base film and the barrier layer, a modified layer formed of a two-component curable adhesive such as a mixture of polyester, polyurethane and isocyanate compound is provided. It is described that it is good. And in all the Examples of this literature, such an improved layer is provided in the overlap film. Further, it is described that the barrier layer can use a water-soluble polymer such as polyvinyl alcohol, and may contain a hydrolyzate of a metal alkoxide if necessary. Furthermore, it is described that the heat seal layer can be formed of a heat seal agent such as polyester, polyurethane, EVA (ethylene-vinyl acetate), acrylic, and SBR (styrene butadiene rubber). However, in such a laminated film, it is difficult to provide sufficient adhesion between the base film and the barrier layer without providing a modified layer. Further, the water resistance of the barrier layer is low, and when an aqueous heat sealant is directly applied to the barrier layer, the barrier layer may be dissolved and transparency may be lowered.

  Japanese Patent Application Laid-Open No. 2001-19781 (Patent Document 3) is formed of a base film and a resin composition provided on one surface of the base film and having a polyvinyl alcohol resin as a main component of the vehicle. An overlapping film composed of the barrier resin layer thus formed and a heat-sealable resin layer provided on both surfaces thereof and formed of a polyester resin is disclosed. In this document, the barrier resin layer contains a metal alkoxide compound or a decomposition product thereof, a dialdehyde compound, a dicarboxylic acid compound, a diimide compound, a di- or polyhydric alcohol compound, a diamine compound, a diisocyanate compound, a bisepoxy compound, a bis It is described that a crosslinking agent such as an ethyleneimine compound, a divinyl compound, a zirconium compound, and a titanium chelate compound, and a silane coupling agent may be included. This document also describes a method for forming a heat-sealable resin layer by forming a polyester resin film or sheet and then laminating it through an adhesive layer for lamination or an anchor coat layer. ing. And in all the Examples of this document, such an anchor coat layer is provided between the barrier resin layer and the heat seal layer. However, with such a laminated film, it is difficult to provide sufficient adhesion between the base film and the barrier resin layer. Also, the water resistance of the barrier resin layer is low, and when an aqueous heat sealant is applied without providing an adhesive layer for laminating or an anchor coat layer, the barrier layer may be dissolved and the transparency may be lowered.

  Furthermore, in Japanese Patent Application Laid-Open No. 2001-80003 (Patent Document 4), an undercoat layer, an inorganic layered compound, and a water-soluble polymer such as polyvinyl alcohol are provided on at least one surface of a base material made of a plastic material. A gas barrier plastic film laminate comprising a gas barrier coating layer as a constituent component and an acrylic resin and sequentially laminating an overcoat layer for improving the thickness of printing ink is disclosed. This document describes that a print layer may be provided on the overcoat layer, and that a heat seal layer may be provided on the print layer. The undercoat layer is intended to increase the adhesion between the base material and the gas barrier coating layer, and is preferably a polyurethane-based resin, and the overcoat layer is intended to improve the thickness of the printing ink. It is also described that a mixture of an acrylic polyol and an isocyanate compound is preferable. Further, in this document, the gas barrier layer may contain a hydrolyzate of a metal alkoxide (such as tetraethoxysilane) in order to improve the temperature / humidity dependency of gas barrier properties, coating strength, and water resistance. Has been described. However, in the method of this document, not only the adhesion between the substrate and the gas barrier coating layer cannot be improved, but also the gas barrier property is not sufficient. Moreover, since an undercoat layer and an overcoat layer are required, a complicated process is required for production of the laminated film.

JP 2000-177066 A (Patent Document 5) discloses a saponified product 100 of a fatty acid vinyl ester copolymer containing 0.05 to 15 mol% of diacetone acrylamide units on at least one surface of a thermoplastic resin film. A laminated film having a crosslinked film obtained by reacting 0.1 to 20 parts by weight of a crosslinking agent (such as a hydrazine compound) with respect to parts by weight is disclosed. It is also described that the fatty acid vinyl ester copolymer is a copolymer obtained by copolymerizing 0.05 to 10 mol% of an α-olefin polymer unit. JP-A-8-15142 (Patent Document 6) reacts 0.1 to 20 parts by weight of hydrazines with respect to 100 parts by weight of a polyvinyl alcohol resin containing 0.05 to 50 mol% of diacetone groups. And a method for making the polyvinyl alcohol resin water resistant is disclosed. When the compositions described in these documents are used, the gas barrier property can be improved to some extent. However, even if these compositions are applied to a substrate film, it is difficult to greatly improve the gas barrier property, particularly the gas barrier property under high humidity, and such a water-resistant barrier layer is used. However, it has been a problem that it dissolves when an aqueous coating agent (aqueous paint) is coated. In order to improve adhesion, an anchor layer may be formed between the base film and the coating layer (barrier layer) as described above. However, when the anchor layer is formed, not only the production process of the laminated film is increased and the productivity is lowered, but also, since the coating solution for the anchor layer usually contains an organic solvent, it is difficult to make the coating solution aqueous. is there.
JP-A-8-80964 (Claims) JP-A-11-333967 (claims, paragraph numbers [0017] [0023] [0028]) JP 2001-19781 A (claims, paragraph numbers [0013] to [0016], [0021] to [0023]) JP 2001-80003 A (claims, paragraph numbers [0031] [0051]) JP 2000-177066 A (Claims) JP-A-8-15142 (Claims)

  Accordingly, an object of the present invention is to provide a laminated film (packaging film) that can effectively prevent erosion of the barrier layer and maintain high gas barrier properties even when an aqueous coating agent (aqueous heat sealant) is applied. It is in.

  Another object of the present invention is to provide a non-chlorine-based laminated film having high adhesion of the barrier layer to the base film and high gas barrier properties (or aroma retention).

  Still another object of the present invention is to provide a laminated film having a high gas barrier property in which the barrier layer is securely and firmly adhered to the base film without interposing an anchor layer.

  Another object of the present invention is to provide a laminated film that is excellent in adhesion to a base film and gas barrier properties, and can be easily and efficiently produced under aqueous conditions without using a solvent-based coating agent. is there.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor has found that a water-soluble polymer compound [in particular, a vinyl alcohol polymer such as a vinyl alcohol polymer having a carbonyl group (active carbonyl group)] and the water Combining a crosslinking agent (for example, a hydrazine-based crosslinking agent) capable of crosslinking a functional polymer compound with (and, if necessary, an inorganic layered compound) not only exhibits high gas barrier properties, but also has no anchor layer. The barrier layer (coating layer) can be formed with high adhesion to the base film, the water resistance of the coating layer is greatly improved, and an aqueous heat sealant (especially a non-chlorine heat sealant) is formed on the coating layer. It has been found that a laminated film excellent in gas barrier properties can be obtained without causing erosion or dissolution of the coating layer even when applied.

  That is, the laminated film (gas barrier laminate film) of the present invention is composed of a base film, a barrier layer formed on at least one surface of the base film, and a heat seal layer formed on the barrier layer. The barrier layer is composed of a water-soluble polymer compound and a crosslinking agent, and the heat seal layer is directly formed on the barrier layer with an aqueous coating solution (or an aqueous coating agent). . In such a laminated film, the barrier layer may be directly formed on the base film without interposing an anchor coat layer. The base film may be composed of at least one thermoplastic resin selected from an olefin resin, a polyester resin, and a polyamide resin, particularly an ethylene resin or a propylene resin (particularly a terpene resin). And a propylene-based resin containing at least one selected from petroleum resins.

  In the barrier layer, the water-soluble polymer compound may be composed of, for example, a vinyl alcohol polymer. The barrier layer may further contain an inorganic layered compound (such as montmorillonite). Such a barrier layer may be composed of, for example, a vinyl alcohol polymer having a carbonyl group, a compound having a plurality of hydrazino groups, and an inorganic layered compound. The vinyl alcohol polymer having a carbonyl group is at least one of polyvinyl alcohol and an ethylene-vinyl alcohol copolymer, and contains a carbonyl group at a concentration of about 0.05 to 25 mol%. A polymer may be used. The vinyl alcohol polymer having a carbonyl group may contain a diacetone acrylamide unit. The ratio of the crosslinking agent (for example, the compound having a plurality of hydrazino groups) to 100 parts by weight of the inorganic layered compound may be about 1 to 80 parts by weight. The barrier layer may contain a crosslinking agent (for example, the plurality of hydrazinos) with respect to 100 parts by weight of a water-soluble polymer compound (for example, a vinyl alcohol polymer such as a vinyl alcohol polymer having a carbonyl group). The compound having a group) may contain about 1 to 20 parts by weight and about 5 to 70 parts by weight of the inorganic layered compound.

  The heat seal layer (or heat sealant or sealant constituting the heat seal layer) may be composed (or formed) of non-chlorine resin (vinyl chloride resin, vinylidene chloride resin, etc.), for example, olefin It may be formed of at least one resin selected from a resin, an acrylic resin, and a vinyl acetate resin.

  As a typical laminated film, a base film composed of a propylene-based resin containing at least one selected from terpene-based resins and petroleum resins, a carbonyl film formed directly on at least one surface of the base film, and A barrier layer composed of a vinyl alcohol polymer having a group, a polyvalent carboxylic acid polyhydrazide compound, and an inorganic layered compound, and formed directly on the barrier layer, from an olefin resin, an acrylic resin, and a vinyl acetate resin. A laminated film composed of a heat seal layer formed with an aqueous coating agent containing at least one selected resin can be exemplified.

The laminated film of the present invention is excellent in barrier properties such as water and oxygen. For example, the water vapor permeability under an atmosphere of a temperature of 40 ° C. and a humidity of 90% RH is, for example, 4.0 g / m ² · day or less ( For example, it may be about 1.0 to 4.0 g / m ² · day).

  In addition, the said barrier layer may be normally formed with the coating agent (especially aqueous coating liquid), and may be aged. For example, the barrier layer is a barrier layer formed of an aqueous coating liquid composed of the water-soluble polymer compound and a crosslinking agent, and after applying the aqueous coating liquid, a predetermined temperature (for example, 35 ° C. or higher) ) For a predetermined time (for example, 12 hours or more).

  The laminated film of the present invention can be produced by forming the barrier layer on at least one surface of the substrate film and directly forming the heat seal layer on the barrier layer. In a typical method, a barrier layer is formed by applying a coating liquid (usually an aqueous coating liquid) composed of a water-soluble polymer compound and a crosslinking agent to at least one surface of a base film. Alternatively, a laminated film may be produced by directly applying an aqueous coating liquid containing a heat seal layer component (heat seal agent) to form a heat seal layer. In such a method, aging treatment may be performed after application of the aqueous coating liquid. For example, after applying the aqueous coating liquid composed of the water-soluble polymer compound and the crosslinking agent, a predetermined temperature (for example, 35 Aging treatment may be performed for a predetermined time (12 hours or more) at a temperature of ° C or higher.

  The laminated film of the present invention forms a barrier layer by combining a water-soluble polymer compound (particularly, a vinyl alcohol polymer) and a crosslinking agent. Therefore, even if an aqueous coating agent (aqueous heat sealing agent) is applied, the barrier film is used. Erosion of the layer can be effectively prevented and high gas barrier properties can be maintained. In addition, the adhesion of the barrier layer to the base film is high, and even if a heat sealant of non-chlorine resin (particularly non-vinylidene chloride resin) is used, it has a high gas barrier property (or aroma retaining property). Yes. Furthermore, the barrier layer adheres securely and firmly to the base film without interposing an anchor layer, and has high gas barrier properties. As described above, the laminated film (non-chlorinated laminated film) of the present invention is excellent in adhesion to the base film and gas barrier properties, and can be produced under aqueous conditions without using a solvent-based coating agent. Moreover, since a laminated film (base film, barrier layer, heat seal layer) can be formed from a non-halogen resin under such aqueous conditions, environmental pollution can be significantly reduced even after production and after production.

  The laminated film of the present invention is composed of a base film, a barrier layer formed on at least one surface of the base film, and a heat seal layer formed on the barrier layer.

[Base film]
The kind in particular of base film is not restrict | limited, For example, papers, metal foil, and plastic films can be illustrated. Examples of the plastic constituting the films include olefin resins, polyester resins (polyethylene terephthalate, polybutylene terephthalate, homo or copolyalkylene arylates such as polyethylene naphthalate, liquid crystalline polyester, etc.), polyamide resins (nylon 6, Nylon 66, nylon 12, etc.), styrene resins (polystyrene, acrylonitrile-styrene copolymers, etc.), polycarbonate resins, polysulfone resins, polyphenylene ether resins, polyphenylene sulfide resins, polyvinyl alcohol resins, cellulose ester resins. And biodegradable resins (aliphatic polyester resins such as polylactic acid, aliphatic polyamide resins, etc.). The base film may be a single base film, or a composite base film composed of a plurality of layers (for example, a laminated paper of paper and plastic, a laminate of a plastic film and an aluminum foil, plastics Or the like. The base film may be a biodegradable film (for example, an aliphatic polyester resin film). Among these base films, olefin resins (ethylene resins, propylene resins, etc.), polyester resins (for example, aromatic polyester resins such as poly C _2-4 alkylene arylate or copolyester), polyamide resins, etc. In particular, a base film (or nonpolar film) composed of an olefin resin is preferable. The base film is usually composed of a thermoplastic resin.

Examples of the olefin resin include olefin homo- or copolymers. Examples of the olefin include α-C _2-16 olefins such as ethylene, propylene, 1-butene, isobutene, 4-methyl-1-butene, 1-pentene, 3-methyl-1-pentene and 1-hexene. Can be mentioned. These olefins may be used alone or in combination of two or more. Of these olefins, α-C _2-8 olefins, preferably α-C _2-4 olefins (ethylene, propylene, etc.), more preferably at least propylene are included.

The olefin resin may be a copolymer of an olefin and a copolymerizable monomer. Examples of the copolymerizable monomer include (meth) acrylic acid ester [for example, (meth) acrylic acid C _1-6 alkyl ester]; vinyl esters (for example, vinyl acetate); cyclic olefins (norbornene, ethylidene norbornene) And cyclopentadiene); dienes and the like. The copolymerizable monomers can be used alone or in combination of two or more. The usage-amount of a copolymerizable monomer can be selected from the range of about 0-100 weight part with respect to 100 weight part of olefins, Preferably it is 0-50 weight part, More preferably, it is about 0-25 weight part.

  Examples of the olefin resin include ethylene resins [for example, low, medium or high density polyethylene, linear low density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene. -1 copolymer, ethylene- (4-methylpentene-1) copolymer, etc.], propylene resin (for example, polypropylene, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene- And propylene containing 80% by weight or more of propylene such as butene-1 copolymer) and poly (methylpentene-1) resin. Examples of the copolymer include ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer or its ionomer, ethylene- (meth) acrylate copolymer such as ethylene-ethyl acrylate copolymer, Examples include maleic anhydride grafted polypropylene. The copolymer (a copolymer of olefins and a copolymer of an olefin and a copolymerizable monomer) includes a random copolymer, a block copolymer, or a graft copolymer.

  Of these olefin resins, propylene resins are preferred from the viewpoints of heat resistance, oil resistance, strength and rigidity. The propylene-based resin includes a propylene homopolymer or a propylene-α-olefin copolymer. In the propylene resin (including the copolymer), the ratio (weight ratio) of propylene and α-olefin is propylene / α-olefin = 60/40 to 100/0, preferably 70/30 to 100/0, Preferably, it may be about 80/20 to 100/0 (particularly 90/10 to 100/0).

  The propylene-based resin may have an atactic structure, but may have stereoregularity such as an isotactic, syndiotactic, or metallocene structure generated by a metallocene catalyst. From the viewpoint of economy and the like, a propylene-based resin having an isotactic structure is preferable.

  The base resin of the base film (especially olefin resin such as propylene resin) may contain at least one resin selected from terpene resin and petroleum resin in order to improve moisture resistance or water vapor barrier property. Good.

  Examples of the terpene-based resin include polymers of terpenes (such as pinene, kalen, myrcene, osimene, limonene, terpinolene, terpinene, sabinene, tricyclene, pisapolene, gingipeperene, santalen, camphorene, mylene, and totalene), or hydrogenation thereof. (For example, a resin hydrogenated at a hydrogenation rate of 80% or more). These terpene resins preferably do not contain polar groups.

Examples of petroleum resins include aliphatic petroleum resins mainly composed of C _5-9 fractions (higher olefin hydrocarbons), dicyclopentadiene petroleum resins, and aromatic hydrocarbons such as vinyltoluene and indene. Examples thereof include petroleum resins as components, and hydrogenated products thereof (for example, resins hydrogenated at a hydrogenation rate of 80% or more). These petroleum resins preferably do not contain polar groups. Specific examples of such petroleum resin include trade name “Arcon P-125” manufactured by Arakawa Chemical Co., Ltd., “Escollet 5320HC” manufactured by Tonex Co., Ltd., and the like.

  The content of the terpene resin and / or petroleum resin may be 1 to 25 parts by weight (for example, 1 to 10 parts by weight), preferably about 5 to 20 parts by weight with respect to 100 parts by weight of the base resin.

  In addition, the base film which uses a terpene resin and / or a petroleum resin and uses a propylene resin to which moisture proofing etc. are provided as a base resin usually has low adhesion. However, in the present invention, it is possible to form a barrier layer with high adhesion even for such a base film. Therefore, a barrier layer can be directly formed on the base film without using an anchor coating agent containing an organic solvent, and the burden on the environment can be reduced.

  For the base film, stabilizers (antioxidants, UV absorbers, light stabilizers, heat stabilizers, etc.), crystal nucleating agents, flame retardants, flame retardant aids, fillers, plastics, as necessary. Agents, impact modifiers, reinforcing agents, colorants, dispersants, antistatic agents, foaming agents, antibacterial agents, and the like may be added. These additives can be used alone or in combination of two or more.

  The base film may be an unstretched film, but is usually stretched (uniaxial or biaxial). Usually, as a base film, a uniaxially stretched film or a biaxially stretched film, especially a biaxially stretched film is often used. Further, the surface of the base film may be subjected to surface treatment such as discharge treatment such as corona discharge or glow discharge, acid treatment, and wrinkle treatment in order to improve adhesion.

  Furthermore, as a base film, a vapor deposition film in which a metal (such as aluminum) or a metal oxide (such as silica or alumina) is deposited can be used.

  The thickness of the base film is, for example, about 5 to 100 μm, preferably 10 to 70 μm, and more preferably about 15 to 50 μm.

[Barrier layer]
The barrier layer (coating layer) may be formed on at least one surface of the base film, and may be formed on both surfaces of the base film. Such a barrier layer is composed of at least a water-soluble polymer compound and a crosslinking agent.

(Water-soluble polymer compound)
Examples of water-soluble polymer compounds for forming the barrier layer include vinyl alcohol polymers (vinyl alcohol resins), acrylic resins (polyacrylic acid, etc.), cellulose resins (alkyl cellulose (methyl cellulose, etc.), hydroxyalkyl Examples thereof include cellulose (such as hydroxymethylcellulose and hydroxyethylcellulose) and cellulose ethers such as carboxymethylcellulose], polysaccharides and derivatives thereof (such as starch, amylose, amylopectin, pullulan, curdlan, xanthan, chitin, and chitosan). The water-soluble polymer compounds may be used alone or in combination of two or more. Of these, preferred water-soluble polymer compounds are vinyl alcohol polymers.

Examples of the vinyl alcohol polymer include a saponified product of a fatty acid vinyl ester alone or a copolymer, a saponified product of a copolymer of a fatty acid vinyl ester and a copolymerizable monomer, and the like. Examples of the fatty acid vinyl ester include vinyl acetate and vinyl propionate, and vinyl acetate is usually used. Examples of the copolymerizable monomer include C _2-4 olefins (ethylene, propylene, butene, etc.), (meth) acrylic acid, (meth) acrylic acid esters, alkyl vinyl ethers, vinyl pyrrolidone, and the like. As the copolymerizable monomer, a monomer containing at least ethylene, particularly ethylene is used. The vinyl alcohol polymer may be modified (acetalized, phosphoric esterified, acetylated, etc.).

  Examples of typical vinyl alcohol polymers include saponified products (such as ethylene-vinyl alcohol copolymers) of polyvinyl alcohol and copolymers of fatty acid vinyl esters and copolymerizable monomers. In particular, at least one polymer selected from polyvinyl alcohol and ethylene-vinyl alcohol copolymer can be suitably used from the viewpoint of gas barrier properties. A preferred vinyl alcohol polymer is an ethylene-vinyl alcohol copolymer. In the ethylene-vinyl alcohol copolymer, the ethylene content may be a relatively small amount, for example, 1 to 10% by weight, preferably 2 to 7% by weight, more preferably about 2 to 5% by weight. The degree of saponification of the vinyl alcohol polymer is usually 80 mol% or more (for example, about 80 to 100 mol%), preferably 90 mol% or more (for example, about 90 to 99.5 mol%), Preferably it is 95 mol% or more (for example, about 95-99 mol%).

  The degree of polymerization of the vinyl alcohol polymer is, for example, 200 or more (for example, 200 to 5000), preferably 250 to 5000, and more preferably about 300 to 3000.

  The vinyl alcohol polymer may be a vinyl alcohol polymer having a carbonyl group. Such a vinyl alcohol polymer can be further improved in water resistance, gas barrier properties, adhesion to a substrate film, and the like by combining with a crosslinking agent (for example, hydrazine crosslinking agent) described later. Examples of the vinyl alcohol polymer having a carbonyl group include a saponified product of a copolymer of a fatty acid vinyl ester and a monomer having a carbonyl group, a fatty acid vinyl ester, a copolymerizable monomer, and a monomer having a carbonyl group. And a saponified product of the copolymer. In the vinyl alcohol polymer having such a carbonyl group, the same compound as described above can be used as the fatty acid vinyl ester and the copolymerizable monomer. Moreover, the saponification degree, polymerization degree, and ethylene content of the vinyl alcohol polymer having such a carbonyl group are the same as described above.

  In the vinyl alcohol polymer having a carbonyl group, the carbonyl group is derived from various carbonyl groups, for example, carbonyl groups such as vinyl ketones, diketo groups such as acetylacetonato group, diacetone groups such as diacetone acrylamide group, etc. May be. An active methylene group may be adjacent to the carbonyl group. That is, the carbonyl group may be a carbonyl group adjacent to the active methylene group. The carbonyl group may be introduced by copolymerization of a polymerizable monomer having a carbonyl group, or may be introduced by modifying a vinyl alcohol polymer (carbonylation by acetoacetylation or the like). Industrially, vinyl alcohol polymers having a carbonyl group often contain diacetone acrylamide units.

  In the vinyl alcohol polymer having a carbonyl group, the concentration of the carbonyl group is, for example, 0.01 to 25 mol% (for example, 0.05 to 25 mol%), preferably 0.05 to 20 mol% (for example, 0.1 to 20 mol%), more preferably about 0.05 to 10 mol% (for example, 0.1 to 10 mol%), and usually about 1 to 10 mol%. The concentration of the carbonyl group means a ratio in terms of monomer. For example, even a diacetone group composed of two carbonyl groups is not regarded as two carbonyl groups, but in terms of diacetone acrylamide. The percentage of use is shown.

  The vinyl alcohol polymers may be used alone or in combination of two or more. For example, a vinyl alcohol polymer not containing a carbonyl group may be combined with a vinyl alcohol copolymer having a carbonyl group (for example, a carbonyl group adjacent to an active methylene group). The latter (weight ratio) = 0/100 to 90/10, preferably 0/100 to 75/25, and more preferably about 0/100 to 60/40.

(Crosslinking agent)
The cross-linking agent is not particularly limited as long as it can cross-link the water-soluble polymer compound. For example, a coupling agent (such as a silane coupling agent), a dialdehyde compound ( glyoxal, such as C _2-10 alkylene aldehydes such as glutaraldehyde), dicarboxylic acid compounds (such as C _2-10 dicarboxylic acid such as adipic acid), diimide compound (carbodiimide, etc.), polyisocyanate compound (diisocyanate compound), oxazoline In addition to conventional crosslinking agents such as compounds, zirconium compounds (such as zirconium carbonates such as zirconium carbonate and zirconium acetate), hydrazine-based crosslinking agents and the like can be exemplified. In the present invention, the crosslinking agent usually does not contain a hydrolysis polycondensation product of a metal alkoxide (such as a compound described in JP-A No. 11-333967). The crosslinking agents may be used alone or in combination of two or more. Among these cross-linking agents, in particular, when a hydrazine-based cross-linking agent, the vinyl alcohol polymer (particularly, the vinyl alcohol polymer having a carbonyl group), and (preferably further an inorganic layered compound described later) are combined. The adhesion and water resistance of the barrier layer to the substrate can be further improved.

Examples of hydrazine-based crosslinking agents (compounds having a plurality of hydrazino groups) include hydrazine, hydrazine hydrate, carbohydrazide, polyhydric carboxylic acid polyhydrazide compounds, poly (meth) acrylic acid hydrazide, ketones (acetone) with these hydrazine compounds. , Methyl ethyl ketone, and the like) can be exemplified. Examples of the polycarboxylic acid polyhydrazide compounds include dibasic acid dihydrazide (oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide dihydrazide , Dodecanedioic acid dihydrazide, hexadecanoic acid dihydrazide, etc. C _2-20 alkane dicarboxylic acid dihydrazide; cyclohexanedicarboxylic acid dihydrazide etc., C _4-10 cycloalkane dicarboxylic acid dihydrazide; phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, naphthoic acid heterocyclic dicarboxylic acid di such as pyridine dicarboxylic acid dihydrazide; C _8-16 array Nji carboxylic acid dihydrazide such as dihydrazide Dolazide; dibasic oxyacid dihydrazide such as malic acid dihydrazide, tartaric acid dihydrazide; iminodiacetic acid dihydrazide, etc., polycarboxylic acid polyhydrazide (cyclohexanetricarboxylic acid trihydrazide, benzenetricarboxylic acid trihydrazide, pyromellitic acid tetrahydrazide, citric acid, etc. And polybasic oxyacid hydrazide, ethylenediaminetetraacetic acid tetrahydrazide, etc.). These crosslinking agents can be used alone or in combination of two or more.

Of these crosslinking agents (hydrazine-based crosslinking agents), water-soluble or water-dispersible compounds such as C _2-7 alkanedicarboxylic acid dihydrazide, particularly C _4-7 alkanedicarboxylic acid dihydrazide (such as adipic acid dihydrazide) may be used. Many.

(Inorganic layered compound)
The barrier layer may further contain an inorganic layered compound. The inorganic layered compound has a structure in which unit crystal layers are laminated, and exhibits a property of swelling or cleaving by coordinating or absorbing a solvent (particularly water) between the layers. Examples of such inorganic layered compounds include swellable hydrous silicates such as smectite group clay minerals (montmorillonite, beidellite, nontronite, saponite, hectorite, soconite, stevensite, etc.), vermiculite group clay minerals (vermiculite, etc.) ), Kaolin-type minerals (such as halloysite, kaolinite, enderite, dickite), phyllosilicates (such as talc, pyrophyllite, mica, margarite, muscovite, phlogopite, tetrasilic mica, teniolite), jamonite Examples include group minerals (such as antigolite), chlorite group minerals (such as chlorite, cookite, and nanthite). These inorganic layered compounds may be natural products or synthetic products. These inorganic layered compounds can be used alone or in combination of two or more. Of these inorganic layered compounds, smectite group clay minerals, particularly montmorillonite, are preferred.

  The inorganic layered compound is used in the form of particles (fine particles). The particulate inorganic layered compound (inorganic layered particle) is usually plate-shaped or flat-shaped, and the planar shape is not particularly limited, and may be an amorphous shape. The average particle diameter (planar average particle diameter) of the inorganic layered compound particles is, for example, 0.01 to 5 μm, preferably 0.1 to 3 μm, and more preferably 0.2 to 2 μm (for example, 0.5 to 0.5 μm). 2 μm). The particulate inorganic layered compound (inorganic layered particle) may be prepared by dispersing the inorganic layered compound in an aqueous medium at high pressure. Further, as the inorganic layered compound, an inorganic layered compound obtained by ion exchange of interlayer ions with a cation may be used.

(Ratio of each component)
The amount of the crosslinking agent (for example, a compound having a plurality of hydrazino groups) is used to increase the water resistance of the barrier layer and the adhesion to the substrate film, so that the water-soluble polymer compound (especially the vinyl having the carbonyl group) is used. For example, 1 to 20 parts by weight, preferably 2 to 17 parts by weight, and more preferably about 3 to 15 parts by weight with respect to 100 parts by weight of the vinyl alcohol polymer such as an alcohol polymer.

  Moreover, when using an inorganic layered compound, the usage-amount of an inorganic layered compound can be selected from the range which does not impair barrier property and water resistance, and is 100 weight part of said water-soluble polymer compounds (especially vinyl alcohol polymer). On the other hand, it is about 5 to 70 parts by weight, preferably about 10 to 60 parts by weight, and more preferably about 10 to 50 parts by weight (for example, 15 to 35 parts by weight).

  Furthermore, in order to further improve the water resistance as well as the barrier property under high humidity and the adhesion to the base film, the ratio of the crosslinking agent to 100 parts by weight of the inorganic layered compound (or inorganic layered particles) is 1 to 80 parts by weight. , Preferably 3 to 60 parts by weight, more preferably 5 to 50 parts by weight), particularly 10 to 40 parts by weight (for example, 15 to 35 parts by weight).

  In addition, the barrier layer may contain the same additive as the said base film, if necessary. In particular, the antistatic agent can efficiently prevent the charging of the laminated film, and can prevent the forming efficiency of the laminated sheet and various electrostatic disturbances (such as peeling charging). As the antistatic agent, a conventional antistatic agent (surfactant) can be used, and any of nonionic, anionic, cationic and amphoteric antistatic agents (surfactants) may be used. In the present invention, a cationic antistatic agent can be preferably used. Since the cationic antistatic agent can be bonded (for example, ionic bond) to the inorganic layered compound (or between the layers of the inorganic layered compound), it can efficiently impart antistatic properties to the laminated film (or barrier layer).

Examples of the cationic antistatic agent (cationic surfactant) include amine salts (first to tertiary amine salts), quaternary ammonium salts, and phosphonium salts. Examples of the amine constituting the amine salt include primary amines (for example, C _6-30 alkyl amines such as octyl amine, dodecyl amine, octadecyl amine, preferably C _8-24 alkyl amines), secondary amines (for example, DiC _6-30 alkylamines such as dioctylamine, dioctadecylamine, preferably _{diC8-24alkylamines} ; C _1-8 alkyl-C _6-30 alkylamines such as _{methyloctadecylamine} , preferably C _1-6 Alkyl-C _8-24 alkylamine), tertiary amines (eg, tri-C _6-30 alkylamines such as trioctylamine, preferably tri-C _8-24 alkylamines; di-C _1-8 such as dimethyldodecylamine) Alkyl-C _6-30 alkyl amines, preferably di-C _1-6 alkyl-C _8-24 alkyl amines; C _1-8 alkyls such as didodecyl monomethyl amine Ru-diC _6-30 alkylamine, preferably C _1-6 alkyl-diC _8-24 alkylamine).

The quaternary ammonium (or quaternary ammonium ion) constituting the quaternary ammonium salt is tetraalkylammonium [for example, tetra C _1-12 alkyl ammonium such as tetraethyl ammonium, preferably tetra C _1-8 alkyl ammonium. Tri-C _1-8 alkyl-mono C _6-30 alkyl ammonium such as octadecyl trimethyl ammonium, lauryl trimethyl ammonium, cetyl trimethyl ammonium, preferably tri-C _1-6 alkyl-mono C _8-24 alkyl ammonium; dimethyl dioctadecyl ammonium di C _1-8 alkyl such as - di C _6-30 alkylammonium, preferably di C _1-6 alkyl - di C _8-24 alkyl ammonium; dihydroxyethyl methyl ammonium; methyl dodecyl bis (polyethylene Glycol) ammonium; methyl diethyl (polypropylene glycol) ammonium, di C _1-8 alkyl -C _6-30 alkyl, such as trialkyl benzyl ammonium (cetyl benzyl dimethyl ammonium - benzyl ammonium, preferably di C _1-6 alkyl - C _8-24 alkyl-benzylammonium), alkyl pyridinium (C _6-30 alkyl pyridinium such as cetyl pyridinium, preferably C _8-24 alkyl pyridinium), benzethonium, alkyl imidazolinium and the like.

Examples of the phosphonium ion constituting the phosphonium salt include tetraalkylphosphonium [for example, tetra-C _1-6 alkylphosphonium such as tetraethylphosphonium and tetrabutylphosphonium, and tri-C _1-6 alkyl-C _8-24 alkyl such as hexadecyltributylphosphonium. Phosphonium, tetra (hydroxymethyl) phosphonium and the like], 2-hydroxyethyltriphenylphosphonium and the like.

  Further, the salt constituting the cationic surfactant is not particularly limited, and an organic acid (acetic acid, lactic acid, citric acid, etc.), an inorganic acid (hydrogen chloride, bromide, etc.) depending on the type of the cationic surfactant. Hydrogen, sulfuric acid, etc.), halogen atoms (chlorine atom, bromine atom, etc.), etc.

A preferred cationic surfactant is a quaternary ammonium salt. Representative quaternary ammonium salts include, for example, tetraalkylammonium salts (eg, mono- or di-C _8-24 alkyl-tri or dimethylammonium salts such as lauryltrimethylammonium chloride, dioctadecyldimethylammonium chloride), tri Alkylbenzylammonium salts [for example, C _8-24 alkylbenzyldimethylammonium salts (eg, benzalkonium chloride) such as cetylbenzyldimethylammonium chloride], benzethonium chloride, alkylpyridinium salts (eg, C ₈ such as cetylpyridinium bromide) _-24 alkylpyridinium salts, etc.).

  Antistatic agents (particularly cationic surfactants) may be used alone or in combination of two or more.

  The proportion of the antistatic agent is, for example, about 0.1 to 30 parts by weight, preferably about 0.5 to 20 parts by weight, and more preferably about 1 to 15 parts by weight with respect to 100 parts by weight of the vinyl alcohol polymer. There may be. The proportion of the antistatic agent may be, for example, 1 to 100 parts by weight, preferably 2 to 50 parts by weight, and more preferably about 3 to 30 parts by weight with respect to 100 parts by weight of the inorganic layered compound. .

  Furthermore, the barrier layer may contain an antifoaming agent, a viscosity modifier, a preservative, and the like.

  The thickness of the barrier layer can be selected from the range of about 0.2 to 5 μm, for example, 0.2 to 4 μm, preferably 0.3 to 3 μm, and more preferably about 0.5 to 2 μm.

  In the present invention, a barrier layer is formed by combining a water-soluble polymer compound (vinyl alcohol polymer) and a crosslinking agent (and, if necessary, an inorganic layered compound). In addition, the water resistance and adhesion to the substrate film can be greatly improved. Therefore, in the laminated film of the present invention, the barrier layer can be directly formed with high adhesion to the base film without interposing an anchor coat layer between the base film and the barrier layer.

  As will be described later, the barrier layer may be generally formed of a coating liquid (particularly an aqueous coating liquid) composed of a water-soluble polymer compound and a crosslinking agent. Further, such a barrier layer may be subjected to an aging treatment after applying a coating liquid. Depending on the type of raw fabric (or base film) (for example, base film containing the petroleum resin, etc.), gas barrier properties (especially water vapor barrier properties) may be obtained because aging improves crystallization due to aging treatment. It can be further improved and further stabilized. Moreover, the adhesiveness of a base film and a barrier layer can also be improved by an aging process. A preferable barrier layer is, for example, a barrier layer formed of an aqueous coating solution, and after applying the aqueous coating solution, a predetermined temperature (a temperature described later, for example, 35 ° C. or higher) for a predetermined time (a time described later). (For example, 12 hours or more) includes an aged barrier layer.

[Heat seal layer]
The heat seal layer is directly formed on the barrier layer with an aqueous coating liquid (aqueous coating agent) without interposing an anchor coat layer or the like. The resin (sealant or heat sealant) for forming the heat seal layer is not particularly limited as long as the heat seal layer can be formed on the barrier layer with an aqueous coating agent. For example, olefin resin, vinyl chloride resin ( Vinyl chloride-vinyl acetate copolymers, etc.), vinylidene chloride resins (vinylidene chloride-vinyl chloride copolymers, vinylidene chloride- (meth) acrylic acid ester copolymers, vinylidene chloride-acrylonitrile copolymers, etc.), acrylics Resin, vinyl acetate resin, styrene resin [for example, styrene- (meth) acrylic acid ester copolymer, styrene-acrylic acid ester- (meth) acrylic acid copolymer, etc.], polyester resin, thermoplastic urethane type Resin, rubbery polymer (styrene-butadiene copolymer, etc.) It may be. Preferred resins include non-halogen resins (especially non-chlorine resins such as vinyl chloride and vinylidene chloride), especially olefin resins (ionomer resins, etc.), acrylic resins, vinyl acetate resins, etc. Can be mentioned. Such a non-halogen resin can be suitably used because it does not cause environmental pollution even if it is discarded by incineration or the like. The resin (aqueous heat sealant) forming the heat seal layer may be used alone or in combination of two or more.

  Typical olefin-based resins include linear low density polyethylene, low density polyethylene, ethylene-acrylate copolymer (such as ethylene-ethyl acrylate copolymer), ethylene-methacrylate copolymer, ethylene -(Meth) acrylic acid copolymers, ionomer resins, ethylene-vinyl acetate copolymers, polyethylene-based resins such as ethylene-vinyl alcohol copolymers, and amorphous polypropylene-based resins. Of these olefin resins, ionomer resins are particularly preferable.

Typical vinyl acetate resins include vinyl acetate homopolymers, copolymers of vinyl acetate and other copolymerizable monomers, and the like. Examples of the copolymerizable monomer include olefin monomers (such as ethylene), acrylic acid esters (ethyl acrylate, butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and the like). _C1-10 alkyl esters of acrylic acid, methacrylic esters corresponding to these, vinyl aliphatic carboxylates (vinyl propionate, vinyl caprylate, vinyl caproate, vinyl versatate, etc.), unsaturated dicarboxylic esters (maleic acid) Examples thereof include maleic acid dialkyl esters such as diethyl acid, dibutyl maleate and di-2-ethylhexyl maleate, and fumaric acid esters corresponding to these. These copolymerizable monomers can be used alone or in combination of two or more.

Representative acrylic resins include (meth) acrylic monomers alone or copolymers, and copolymers of (meth) acrylic monomers and copolymerizable monomers. Examples of (meth) acrylic monomers include (meth) acrylic acid alkyl esters [for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate. (Meth) acrylic acid C _1-20 such as, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate Examples include alkyl (preferably C _2-10 alkyl (meth) acrylate) and the like, and (meth) acrylic esters such as glycidyl (meth) acrylate. These (meth) acrylic monomers can be used alone or in combination of two or more.

  Examples of the copolymerizable monomer that forms a copolymer with the (meth) acrylic monomer include the styrene monomer (styrene) in addition to the copolymerizable monomer exemplified in the section of the vinyl acetate resin. Etc.), vinyl esters (such as vinyl acetate and the above fatty acid vinyl esters), acrylonitrile and the like. These copolymerizable monomers may be used alone or in combination of two or more. Preferred copolymers of (meth) acrylic monomers and copolymerizable monomers include copolymers of (meth) acrylic acid esters and acrylonitrile.

  In addition, the heat seal layer may contain the same additive as the base film and the barrier layer as necessary. In particular, as with the barrier layer, by adding an antistatic agent (the antistatic agent exemplified above, particularly a cationic antistatic agent) to the heat seal layer, the antistatic property can be efficiently imparted to the laminated film. The proportion of the antistatic agent may be about 0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight, and more preferably about 1 to 15 parts by weight with respect to 100 parts by weight of the resin (sealant). .

  The heat seal layer may contain an adhesive or an adhesive component [for example, an adhesive resin described later, an acrylic resin (acrylic adhesive), a polyamide resin (polyamide adhesive), or the like). . The resin constituting the adhesive may be a resin having a crosslinkable group (or reactive group) such as an amino group. An acrylic adhesive having a crosslinkable group (amino group) can be obtained from Nippon Shokubai Co., Ltd. under the product name “Polyment”. The amount of the adhesive used is, for example, 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and further preferably about 3 to 15 parts by weight with respect to 100 parts by weight of the resin (sealant) constituting the heat seal layer. It may be.

  Although the thickness of a heat seal layer is not specifically limited, For example, 0.1-20 micrometers, Preferably it is 0.3-10 micrometers, More preferably, about 0.5-5 micrometers may be sufficient.

[Laminated film]
As described above, the laminated film of the present invention can be composed of a base film, a barrier layer, and a heat seal layer, and the heat seal layer is directly formed on the barrier layer with an aqueous coating solution (aqueous coating agent). ing. In the present invention, since the barrier layer has high adhesion and high water resistance, even when an aqueous coating agent (aqueous coating liquid, aqueous heat sealant) is applied to the barrier layer, the barrier layer is eroded (or High barrier properties can be maintained without being lost or dissolved. Therefore, in the present invention, a heat seal layer can usually be formed directly on the barrier layer without forming an anchor coat layer.

  The thickness of the entire laminated film may be, for example, about 5 to 200 μm, preferably 10 to 100 μm, and more preferably about 15 to 60 μm (for example, 20 to 50 μm).

  As described above, the barrier layer may be directly formed on the base film, and if necessary, the barrier layer may be formed on the base film via an anchor coat layer (or an adhesive layer) for improving adhesion. You may form, and you may form directly on a base film, without going through an anchor coat layer. As an adhesive component (for example, adhesive resin) constituting the adhesive layer, for example, a urethane resin (such as an isocyanate group-containing polymer), an imino group-containing polymer (such as a polyalkyleneimine such as polyethyleneimine), a polyester resin, Examples thereof include olefin resins (modified polyolefins such as ethylene- (meth) acrylic acid copolymers), rubber adhesives, coupling agents [titanium coupling agents, silane coupling agents] and the like. These adhesive components can be used alone or in combination of two or more. The thickness of the adhesive layer may be about 0.01 to 3 μm, preferably 0.01 to 2 μm, and more preferably about 0.01 to 1 μm. In this invention, since a barrier layer with high adhesiveness with respect to a base material is used, a barrier layer can be directly formed on a base film, without forming an anchor coat layer. Therefore, in the present invention, the barrier layer is usually formed directly on the base film in many cases.

The laminated film (gas barrier laminate film) of the present invention is excellent in gas barrier properties (or fragrance retention). For example, the oxygen permeability (unit: ml / m ² · day · MPa) in an atmosphere of 20 ° C. and 20% humidity is 100 or less (for example, 10 to 80), preferably 15 to 70, and more preferably 20 It is about ~ 60. In addition, the water vapor permeability (unit: g / m ² · day) in an atmosphere of a temperature of 40 ° C. and a humidity of 90% RH is 20 or less (for example, about 0.1 to 18), preferably 10 or less (for example, 0.8. 2 to 8), more preferably 8 or less (for example, about 0.5 to 7), particularly 4 or less (for example, about 1.0 to 4.0). In addition, the thickness of a film may affect gas barrier property depending on a structure, and the thickness (especially water vapor permeability) of the above-mentioned permeability is usually about 10 to 30 μm (for example, 15 to 15 μm). The transmittance in a laminated film of about 25 μm) may be used.

  The laminated film is also excellent in transparency. For example, the haze is 10% or less (for example, 1 to 10%), preferably 9% or less (for example, 1 to 9%), and more preferably 8% or less ( For example, it is about 1 to 8%).

[Production method of laminated film]
The laminated film (gas barrier laminated film) of the present invention can be produced by forming the barrier layer on at least one surface of the base film and directly forming the heat seal layer on the barrier layer.

  The barrier layer may be formed by dry lamination, extrusion lamination, coextrusion lamination, or the like, but is usually provided on at least one surface of the base film (via an anchor coating layer if necessary, usually an anchor coating layer). In the case of forming by applying a coating liquid (hereinafter sometimes referred to as a barrier coating liquid) containing the components of the barrier layer (at least a water-soluble polymer compound and a crosslinking agent) without directly forming There are many. The coating solution may be aqueous or non-aqueous, but is usually an aqueous coating agent (specifically, an aqueous coating agent composed of a water-soluble polymer compound and a crosslinking agent). The aqueous coating solution (or aqueous coating agent) contains an aqueous solvent in addition to the components. This aqueous solvent may be water alone, with water and a water-soluble organic solvent (for example, alcohols such as ethanol and isopropanol, cellosolves such as methyl cellosolve, ketones such as carbitols and acetone). It may be configured. From an industrial and environmental point of view, the preferred aqueous solvent is water alone.

  In addition, when adding a cationic antistatic agent (cationic surfactant), the cationic surfactant may be added directly, or the constituent components (amine and acid) of the cationic surfactant are added sequentially. Also good. As the latter addition method, for example, (i) an amine (primary to tertiary amine) constituting an amine salt is added to the coating liquid or a constituent component (inorganic layered compound, etc.) of the coating liquid. An acid (the organic acid, inorganic acid, etc.) is added for neutralization, or (ii) the corresponding acid is added for acidification, and then the amine is added for neutralization to obtain a coating solution. Examples thereof include a method of forming a cationic surfactant. Moreover, you may mix an inorganic layered compound, a cationic surfactant, and an aqueous solvent as needed.

  In addition, the heat seal layer is formed directly on the barrier layer without forming an anchor coat layer (at least a heat seal agent such as an olefin resin, an acrylic resin, a vinyl acetate resin). Etc.) can be formed by applying an aqueous coating solution (aqueous coating agent, aqueous heat sealant).

  The aqueous solvent for the aqueous coating liquid for forming the heat seal layer (hereinafter sometimes referred to as heat sealable coating liquid) is the same as described above, and may be water alone, water and a water-soluble organic solvent, You may comprise. A preferred aqueous solvent is water alone. In the present invention, since the water resistance of the barrier layer is remarkably high, a uniform coating film (heat seal layer) can be formed without damaging the barrier layer even if the heat seal layer is formed with an aqueous coating agent. Therefore, in this invention, while being able to manufacture a laminated | multilayer film on aqueous conditions, while being industrially advantageous, the load with respect to an environment can be reduced.

  The aqueous coating agent for forming the heat seal layer may be a solution type (aqueous solution type) or a dispersion type (or aqueous emulsion type).

  The coating agent (aqueous coating agent) for forming the barrier layer or the heat seal layer can be applied by using a conventional method such as gravure coating, reverse coating, doctor coating, bar coating, dip coating and the like.

  In a typical method for producing a laminated film, an aqueous coating agent composed of a water-soluble polymer compound and a crosslinking agent is applied to at least one surface of a base film to form a barrier layer. In many cases, a heat seal layer is formed by directly applying an aqueous coating liquid containing a constituent of the heat seal layer (at least a heat seal agent).

  In addition, after apply | coating a coating agent (aqueous coating agent) to the said base film or the said barrier layer, you may dry an application surface at suitable temperature (for example, about 80-120 degreeC).

  In addition, after applying a coating solution for a barrier layer or a heat seal layer (usually both aqueous coating solutions), a predetermined temperature [for example, about 30 ° C. or higher (for example, about 30 to 65 ° C.), preferably Is 35 ° C. or higher (for example, about 35 to 60 ° C.), more preferably 40 ° C. or higher (for example, about 40 to 55 ° C.)] for a predetermined time [for example, 12 hours or longer (for example, about 12 to 72 hours), preferably May be aged for 18 hours or more (for example, about 18 to 60 hours), 24 hours or more (for example, about 24 to 48 hours)]. The aging treatment may be performed after application of the barrier coating liquid and / or after application of the heat-sealable coating liquid, and is particularly preferably performed at least after application of the barrier coating liquid. As described above, the aging treatment can efficiently improve the gas barrier property and the adhesion between the base film and the barrier layer.

  The laminated film of the present invention has high adhesion to the base film and is excellent in gas barrier properties (or fragrance retention). And since it can manufacture without providing an anchor-coat layer between a base film and a barrier layer, or between a barrier layer and a heat seal layer, it can manufacture simply and efficiently, without multilayering a multilayer film. In addition, since the barrier layer and the heat seal layer can be formed by application of an aqueous coating agent (particularly, an aqueous coating liquid of a non-chlorine resin) without using an anchor coating liquid containing a solvent-based solvent, industrial and environmental The film having excellent gas barrier properties can be obtained under particularly advantageous conditions (aqueous conditions). Moreover, since a laminated film (base film, barrier layer, and heat seal layer) can be formed with a non-halogen resin under such aqueous conditions, environmental pollution can be significantly reduced. Furthermore, it has a relatively high waist feeling (or rigidity) and can efficiently prevent curling when using a laminated film.

  Therefore, the laminated film of the present invention is useful as a packaging material for various packaging films (for example, pillow packaging films), particularly foods and chemicals that are liable to cause quality deterioration due to water vapor or oxygen. For example, it can be used as a packaging material for foods such as confectionery, food cups and trays, chemicals such as drugs, electronic parts such as semiconductors, or precision parts.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, the evaluation method of the physical property of the laminated | multilayer film obtained by the Example and the comparative example is as follows.

[Water vapor permeability]
According to ASTMF-1249-89, the water vapor transmission rate (water vapor transmission rate) was measured using a water vapor transmission rate measuring device ("PERMATRAN" manufactured by MOCON). The measurement conditions are 40 ° C. and relative humidity 90% RH.

[Oxygen permeability]
According to ASTM D-3985, the oxygen permeability (oxygen permeability) was measured using an oxygen permeability measuring device (“OXTRAN” manufactured by MOCON). The measurement conditions are 20 ° C. and relative humidity 20% RH.

[Seal strength]
Using a heat sealer (manufactured by Tester Sangyo Co., Ltd., “TP70 1B”), the heat seal layers of the laminated films were stacked and covered with a cellophane film (thickness 20 μm), and then a temperature of 120 ° C. and a pressure of 1 kg / cm ² ( About 9.8 × 10 ⁴ Pa), time (sealing time) was 1 second, and heat sealing was performed at a sealing width of 10 mm. The coating with the cellophane film is for preventing contamination of the heat sealer on the heat seal bar of the heat sealer.

  Samples heat-sealed under the above conditions were cut into strips with a width of 15 mm, and the sealing strength was measured. For the seal strength, a tensile tester (Orientec Co., Ltd., “RTM-100”) was used, and the sample base film and the heat seal layer under the conditions of a tensile strength of 300 mm / min and a chart speed of 300 mm / min. Were measured by peeling 180 °.

[appearance]
The appearance after the heat seal layer was applied was visually confirmed, and a case where no whitening occurred in the laminated film (barrier layer) was marked with ○, and a case where even a slight whitening of the laminated film occurred was marked with x. In addition, when the water resistance of the barrier layer is inferior, the barrier layer is redissolved to lower the transparency and whiten. On the other hand, when the water resistance of the barrier layer is high, the barrier layer does not re-dissolve even when an aqueous coating agent is applied, and the transparency is drowned.

[Evaluation of itchiness]
After lightly squeezing the laminated film by hand, the water vapor transmission rate and oxygen transmission rate are measured by the same method as described above. The case where it was evaluated as evaluation x, and the other case (in the case of an increase of less than 20%) was evaluated as evaluation ○.

Examples 1-6
A saponified product of vinyl acetate-diacetone acrylamide copolymer (manufactured by Nippon Vinegar Poval Co., Ltd., “D polymer DF-05”), adipic acid dihydrazide, and montmorillonite in proportions shown in the table (Table 1) The aqueous coating agent was prepared by mixing. This aqueous coating agent was applied to the base film shown in the table in the coating amount (thickness after drying) shown in the table (in Example 3, it was applied to both sides of the base film) and dried at 100 ° C. for 1 minute. After that, an aging treatment was performed at 45 ° C. for 25 hours to form a barrier layer. On this barrier layer, an aqueous coating agent containing the heat sealant shown in the table was applied in the application amount (thickness after drying) shown in the table (in Example 3, it was applied to two barrier layers) and at 40 ° C. Aging treatment was performed for 24 hours to form a heat seal layer.

The aqueous coating agent was prepared as follows. That is, montmorillonite (Kunimine Kogyo Co., Ltd., “Kunipia-G”) was high-pressure dispersed in distilled water at a pressure of 500 to 550 kg / cm ² to prepare an aqueous dispersion having a concentration of 3.5% by weight. A predetermined amount of saponified vinyl acetate-diacetone acrylamide copolymer was added to this aqueous dispersion and heated, and stirred at 95 ° C. for 1 hour to prepare a mixed dispersion (liquid A). And A liquid and adipic acid dihydrazide were added to ion-exchange water, and the aqueous coating agent of the density | concentration shown to a table | surface was prepared.

  Moreover, the aqueous coating agent containing a heat seal agent was used as a coating solution having a concentration of 15% by weight by adding and mixing the heat seal agent shown in the table with water. In Example 3, “S100” and “SK-1000” were mixed at a ratio of the former / the latter (parts by weight) = 100/10.

Comparative Example 1
Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., “PVA105”, degree of saponification 98.5%, degree of polymerization 500) was mixed with distilled water to prepare an aqueous coating agent having a concentration of 7% by weight. This aqueous coating agent was applied to the base film shown in the table with the coating amount (thickness after drying) shown in the table, dried at 100 ° C. for 1 minute, and then subjected to an aging treatment at 45 ° C. for 25 hours to form a barrier layer. Formed. On this barrier layer, an aqueous coating agent containing the heat sealant shown in the table is applied in the application amount (thickness after drying) shown in the table, and subjected to aging treatment at 40 ° C. for 24 hours to form a heat seal layer did.

  In addition, the aqueous coating agent containing a heat seal agent was used as a coating solution having a concentration of 15% by weight by adding and mixing the heat seal agent shown in the table with water.

Comparative Example 2
Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., “PVA105”, saponification degree 98.5%, polymerization degree 500), montmorillonite and distilled water were mixed to prepare an aqueous coating agent having a concentration of 7% by weight. This aqueous coating agent was applied to the base film shown in the table with the coating amount (thickness after drying) shown in the table, dried at 100 ° C. for 1 minute, and then subjected to an aging treatment at 45 ° C. for 25 hours to form a barrier layer. Formed. On this barrier layer, an aqueous coating agent containing the heat sealant shown in the table is applied in the application amount (thickness after drying) shown in the table, and subjected to aging treatment at 40 ° C. for 24 hours to form a heat seal layer did. In addition, the preparation method of an aqueous coating agent is the same as that of the mixed dispersion liquid (A liquid) of Example 1.

  In addition, the aqueous coating agent containing a heat seal agent was used as a coating solution having a concentration of 15% by weight by adding and mixing the heat seal agent shown in the table with water.

Comparative Example 3
An aqueous coating agent containing the heat sealant shown in the table is applied to one side of a polyethylene terephthalate film (Oike Sangyo Co., Ltd., “MOS-TO”) with the application amount (thickness after drying) shown in the table. Aging was performed at 40 ° C. for 24 hours to form a heat seal layer.

  In addition, the aqueous coating agent containing a heat seal agent was used as a coating solution having a concentration of 15% by weight by adding and mixing the heat seal agent shown in the table with water.

Comparative Example 4
Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., “PVA105”, saponification degree 98.5%, polymerization degree 500) and montmorillonite were mixed at a ratio shown in the table to prepare an aqueous coating agent. An anchor coat agent (“Byron 20SS”, manufactured by Toyobo Co., Ltd.) is applied to the base film shown in the table to form an anchor coat layer, and the coating amount (the thickness after drying) shown in the table for the aqueous coating agent ), Dried at 100 ° C. for 1 minute, and then subjected to aging treatment at 45 ° C. for 25 hours to form a barrier layer. On this barrier layer, an aqueous coating agent containing the heat sealant shown in the table is applied in the application amount (thickness after drying) shown in the table, and subjected to aging treatment at 40 ° C. for 24 hours to form a heat seal layer did. In addition, the preparation method of an aqueous coating agent is the same as that of the mixed dispersion liquid (A liquid) of Example 1.

  The characteristics of the laminated films obtained in Examples and Comparative Examples are shown in the table. The symbols or abbreviations in the table are as follows.

“W2”: Biaxially stretched polypropylene resin film treated by corona discharge (manufactured by Daicel Value Coating Co., Ltd., “Senesi WOP W2”)
“W2H”: Corona discharge-treated biaxially stretched polypropylene resin film (manufactured by Daicel Value Coating Co., Ltd., “Senesi WOP W2H”)
“VM-PET”: Polyethylene terephthalate resin film (manufactured by Oike Sangyo Co., Ltd., “MOS-TO”)
"DAPVA" ... Saponified product of vinyl acetate-diacetone acrylamide copolymer "PVA" ... Polyvinyl alcohol "ADH" ... Adipic acid dihydrazide "Layered particles" ... Montmorillonite "S303" ... Ethylene-vinyl acetate emulsion (Syden Chemical Co., Ltd.) "Cybinol S303")
“S75N”: Ionomer resin (Mitsui Chemicals, “Chemipearl S75N”)
“S100”: ionomer resin (Mitsui Chemicals, “Chemipearl S100”)
“SK-1000”: An aqueous emulsion having a primary amino group in the side chain and an acrylic resin as the main chain (manufactured by Nippon Shokubai Co., Ltd., “Polyment SK-1000”).

  In the table, “single side” indicates that a barrier layer is formed on one side of the base film, and “both sides” indicates that a barrier layer is formed on both sides of the base film.

Furthermore, the unit of application amount is “g / m ² ”, and the unit of oxygen permeability is “ml / m ² · day · MPa”. Further, the unit of the seal strength is “N / 15 mm”.

  As is clear from the results of the table, the laminated films of the examples have high gas barrier properties (water vapor permeability and oxygen permeability), adhesion to the base film, and water resistance.

Claims (16)

  A laminated film comprising a base film, a barrier layer formed on at least one surface of the base film, and a heat seal layer formed on the barrier layer, wherein the barrier layer is water-soluble A laminated film comprising a polymer compound and a crosslinking agent, and wherein the heat seal layer is directly formed on the barrier layer with an aqueous coating solution.   The laminated film according to claim 1, wherein the barrier layer is directly formed on the base film without interposing an anchor coat layer.   The laminated film according to claim 1, wherein the base film is composed of at least one thermoplastic resin selected from an olefin resin, a polyester resin, and a polyamide resin.   The laminated film according to claim 1, wherein the base film is composed of an ethylene-based resin or a propylene-based resin.   The laminated film according to claim 1, wherein the base film is composed of a propylene-based resin containing at least one selected from a terpene resin and a petroleum resin.   The laminated film according to claim 1, wherein the water-soluble polymer compound is composed of a vinyl alcohol polymer.   The laminated film according to claim 1, wherein the barrier layer further contains an inorganic layered compound.   The laminated film according to claim 1, wherein the barrier layer comprises a vinyl alcohol polymer having a carbonyl group, a compound having a plurality of hydrazino groups, and an inorganic layered compound.   The vinyl alcohol polymer having a carbonyl group is at least one of polyvinyl alcohol and an ethylene-vinyl alcohol copolymer, and contains a carbonyl group at a concentration of 0.05 to 25 mol%. Laminated film.   The laminated film according to claim 8, wherein the vinyl alcohol polymer having a carbonyl group contains diacetone acrylamide units.   The laminated film according to claim 7, wherein the ratio of the crosslinking agent to 1 to 80 parts by weight relative to 100 parts by weight of the inorganic layered compound.   The laminated film according to claim 7, comprising 1 to 20 parts by weight of a crosslinking agent and 5 to 70 parts by weight of an inorganic layered compound with respect to 100 parts by weight of the water-soluble polymer compound.   The laminated film according to claim 1, wherein the heat seal layer is formed of at least one resin selected from an olefin resin, an acrylic resin, and a vinyl acetate resin.   A base film composed of a propylene resin containing at least one selected from terpene resins and petroleum resins, and a vinyl alcohol polymer formed directly on at least one side of the base film and having a carbonyl group , A polyvalent carboxylic acid polyhydrazide compound, and a barrier layer composed of an inorganic layered compound, and at least one resin selected directly from the olefin resin, acrylic resin and vinyl acetate resin formed directly on the barrier layer The laminated film of Claim 1 comprised by the heat seal layer formed of the aqueous coating liquid containing this. ^2. The laminated film according to claim 1, wherein the water vapor permeability in an atmosphere of a temperature of 40 ° C. and a humidity of 90% RH is 4.0 g / m ² · day or less.   The barrier layer is a barrier layer formed of an aqueous coating liquid composed of a water-soluble polymer compound and a crosslinking agent, and the barrier layer is subjected to an aging treatment at 35 ° C. or higher for 12 hours or more after applying the aqueous coating liquid. The laminated film according to claim 1, which is a layer.