阅读说明：本技术 阻隔性涂料组合物及复合膜 (Barrier coating composition and composite film ) 是由 田中宏树 松冈裕 于 2019-02-06 设计创作，主要内容包括：本发明提供一种能够获得到在煮沸条件及沾水条件下层压强度、密封强度、水蒸气阻隔性以及氧阻隔性优异的复合膜的阻隔性涂料组合物、以及使用该阻隔性涂料组合物所得到的复合膜。本发明涉及一种阻隔性涂料组合物,其特征在于,其包含：水性聚氨酯树脂,具有乙烯链的高极性树脂,以及硅烷偶联剂。(The invention provides a barrier coating composition which can obtain a composite film with excellent lamination strength, sealing strength, water vapor barrier property and oxygen barrier property under boiling condition and water soaking condition, and a composite film obtained by using the barrier coating composition. The present invention relates to a barrier coating composition, characterized in that it comprises: an aqueous polyurethane resin, a highly polar resin having an ethylene chain, and a silane coupling agent.)

1. A barrier coating composition, characterized in that it comprises:

an aqueous polyurethane resin;

a highly polar resin having an ethylene chain; and

a silane coupling agent.

2. The barrier coating composition according to claim 1, wherein the mass ratio of the high-polarity resin having an ethylene chain is 15 to 150 parts by mass with respect to 100 parts by mass of the aqueous polyurethane resin.

3. The barrier coating composition according to claim 1 or 2, wherein the ethylene chain ratio in the highly polar resin having an ethylene chain is 0.5 mol% to 30 mol%.

4. The barrier coating composition according to any one of claims 1 to 3, wherein the high polarity resin having an ethylene chain has an ethylene chain in a main chain.

5. The barrier coating composition of any one of claims 1 to 4, wherein the silane coupling agent is a silane coupling agent having an epoxy group.

6. The barrier coating composition of any one of claims 1 to 5, wherein the barrier coating composition is for lamination.

7. A composite film comprising at least a substrate film, a vapor-deposited layer and a coating layer in this order, wherein the coating layer is formed by applying the barrier coating composition according to any one of claims 1 to 6.

8. The composite film according to claim 7, wherein the vapor deposition layer is one or more vapor deposition layers selected from the group consisting of silica and alumina.

Technical Field

The present invention relates to a barrier coating composition and a composite film having a coating layer formed using the barrier coating composition.

Background

In the field of packaging bags for food packaging use, it is often necessary to manufacture packaging bags having a function capable of hot water treatment and also capable of simply cooking the contents of each bag.

The packaging bag for hot water treatment is effective for long-term storage because it has a high sterilizing effect and is completely sealed, and therefore, the contents are not easily spoiled. However, if the gas barrier property (gas barrier property) is insufficient, oxygen may intrude into the packaging bag during storage, and the contents may deteriorate and deteriorate. Therefore, how to suppress the permeation of oxygen or the like in the packaging bag for hot water treatment is a factor that determines the value of the packaging bag.

Conventionally, in a packaging bag used for packaging purposes such as food and medical use, a method of providing various gas barrier layers (gas barrier layers) for blocking gases such as oxygen and water vapor has been considered. In particular, metals or metal oxides laminated on a printing substrate film or the like by vapor deposition have been conventionally used as materials having high gas barrier properties. Further, in the above-mentioned packaging bag for hot water treatment, a packaging bag for hot water treatment in which an aluminum vapor deposition film or a pure aluminum foil is laminated has also become a mainstream in the case of long-term storage. However, composite laminates using these materials are often expensive. Further, there is a problem that it cannot be used in a field where transparency is required.

In recent years, the use of a gas barrier film (gas barrier film) provided with a base film made of a plastic material, a vapor deposition layer made of a metal oxide, and a coating layer made of a resin has been studied.

As such a gas barrier film, for example, a gas barrier film in which a coating layer contains an aqueous polyurethane resin and a water-soluble polymer has been proposed (for example, see patent document 1). In addition, for example, a transparent gas barrier film having a top coat layer (top coat layer) containing a polyurethane resin and polyvinyl alcohol has also been proposed (for example, see patent document 2).

A gas barrier film having a laminated structure is required to have not only excellent gas barrier properties but also excellent lamination strength. In particular, in the field of packaging bags used for packaging applications such as food and medical use, excellent gas barrier properties are required, and in addition, excellent layer pressure under dry (dry) conditions and excellent lamination strength under wet conditions are also required.

Disclosure of Invention

Problems to be solved by the invention

Accordingly, an object of the present invention is to provide a barrier coating composition capable of providing a composite film excellent in lamination strength under boiling conditions and under wet conditions, sealing strength, water vapor barrier property, and oxygen barrier property, and a composite film obtained by using the barrier coating composition.

Means for solving the problems

As a result of extensive studies, the inventors of the present invention have found that a composite film having excellent lamination strength, sealing strength, water vapor barrier properties and oxygen barrier properties under boiling conditions and under wet conditions can be obtained by using a coating composition containing an aqueous urethane resin, a highly polar resin having an ethylene chain, and a silane coupling agent, because the coating composition has excellent cohesive force of a coating film and adhesion to a vapor deposition film made of a metal oxide when the coating composition is applied.

That is, the barrier coating composition of the present invention is characterized by comprising: an aqueous polyurethane resin, a highly polar resin having an ethylene chain, and a silane coupling agent.

In the barrier coating composition of the present invention, the mass ratio of the highly polar resin having an ethylene chain is preferably 15 to 150 parts by mass with respect to 100 parts by mass of the aqueous urethane resin.

Preferably, the ethylene chain ratio in the highly polar resin having an ethylene chain is 0.5 to 30 mol%.

Preferably, the above-mentioned high-polarity resin having an ethylene chain has an ethylene chain in the main chain.

Preferably, the silane coupling agent is a silane coupling agent having an epoxy group.

Preferably, the barrier coating composition of the present invention is used for lamination.

The present invention also provides a composite film comprising at least a base film, a vapor deposition layer, and a coating layer in this order, wherein the coating layer is formed by applying the barrier coating composition.

In the composite membrane of the present invention, preferably, the vapor deposition layer is one or more vapor deposition layers selected from the group consisting of silica and alumina.

The barrier coating composition and the composite film will be described in detail below.

[ Barrier coating composition ]

First, the barrier coating composition of the present invention will be described.

The barrier coating composition of the present invention comprises: an aqueous polyurethane resin, a highly polar resin having an ethylene chain, and a silane coupling agent.

From the viewpoint of satisfactory gas barrier performance, the aqueous polyurethane resin preferably contains an acid group-containing polyurethane resin and a polyamine compound.

The aqueous polyurethane resin may be a mixture of the acid group-containing polyurethane resin and the polyamine compound, or may be a copolymer.

The bond between the acid group of the acid group-containing polyurethane resin and the polyamine compound is not particularly limited, and may be an ionic bond (for example, an ionic bond between a carboxyl group and a tertiary amino group) or a covalent bond (for example, an amide bond).

The acid group of the acid group-containing polyurethane resin may be bonded to an amino group (primary amino group, secondary amino group, tertiary amino group, etc.) of the polyamine compound, and examples thereof include: carboxyl groups, sulfonic acid groups, and the like. The acid group may be generally neutralized with a neutralizing agent (base) and may form a salt with the base.

The acid group may be located at the terminal of the acid group-containing polyurethane resin or may be located in a side chain, but is preferably located at least in the side chain.

The acid value of the acid group-containing polyurethane resin is preferably 5 to 100mgKOH/g, more preferably 10 to 70mgKOH/g, and still more preferably 15 to 60mgKOH/g, from the viewpoint of satisfactory gas barrier performance and water resistance.

In the present specification, the acid value refers to an acid value measured by a method according to JIS K0070.

From the viewpoint of satisfactory gas barrier properties, the total of the urethane group concentration and urea group (urea group) concentration of the acid group-containing polyurethane resin is preferably 15% by mass or more, and more preferably 20 to 60% by mass.

The urethane group concentration is a ratio of the molecular weight of the urethane group (59 g/equivalent) to the molecular weight of the repeating structural unit of the polyurethane resin.

The urea group concentration represents the ratio of the molecular weight of urea groups (primary amino group (amino group): 58 g/equivalent, secondary amino group (imino group): 57 g/equivalent) to the molecular weight of the repeating structural unit of the polyurethane resin.

When a mixture of two or more species is used as the acid group-containing polyurethane resin, the urethane group concentration and urea group concentration can be calculated based on the feeding of the reaction components, that is, based on the ratio of each component used.

The acid group-containing polyurethane resin usually has at least a rigid unit (a unit composed of a hydrocarbon ring) and a short chain unit (for example, a unit composed of a hydrocarbon chain). That is, the structural unit of the acid group-containing polyurethane resin is generally derived from a polyisocyanate component, a polyhydroxy acid component, a polyol component or a chain extender component (particularly, at least a polyisocyanate component), and includes a hydrocarbon ring (at least one of aromatic and non-aromatic hydrocarbon rings). The proportion of the unit composed of a hydrocarbon ring in the structural units of the acid group-containing polyurethane resin is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, and even more preferably 20 to 60% by mass, based on the total of all the structural units, from the viewpoint of satisfactory expression of gas barrier properties and laminate strength.

The number average molecular weight of the acid group-containing polyurethane resin may be appropriately selected, and is preferably 800 to 1000000, more preferably 800 to 200000, and further preferably 800 to 100000. If the number average molecular weight of the acid group-containing polyurethane resin is within the above range, the viscosity of the barrier coating composition can be made appropriate, and the gas barrier property of the coating layer can be appropriately provided.

In the present specification, the number average molecular weight refers to a value in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC).

The acid group-containing polyurethane resin may be crystalline in order to improve the gas barrier property.

The glass transition temperature (Tg) of the acid group-containing polyurethane resin is preferably 100 to 200 ℃, more preferably 110 to 180 ℃, and even more preferably 115 to 150 ℃ from the viewpoint of satisfactory gas barrier properties.

In the present specification, the glass transition temperature (Tg) is a value measured by Differential Scanning Calorimetry (DSC).

The polyamine compound is preferably a compound having two or more basic nitrogen atoms.

The basic nitrogen atom is a nitrogen atom capable of bonding to an acid group of the acid group-containing polyurethane resin, and examples thereof include: a nitrogen atom in an amino group such as a primary amino group, a secondary amino group, or a tertiary amino group.

The polyamine compound is not particularly limited as long as it is a compound capable of bonding to the acid group of the acid group-containing polyurethane resin to improve the gas barrier property, and various compounds having two or more basic nitrogen atoms can be used.

The polyamine compound is preferably a polyamine compound having two or more amino groups selected from at least one of the group consisting of primary amino groups, secondary amino groups, and tertiary amino groups.

Specific examples of the polyamine compound include: alkylene diamines, polyalkylene polyamines, silicon compounds having a plurality of basic nitrogen atoms, and the like. Examples of the above-mentioned alkylenediamines include: alkylene diamines (alkylene diamines) having 2 to 10 carbon atoms such as ethylenediamine, 1, 2-propylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, and 1, 6-hexamethylenediamine. Examples of the polyalkylene polyamine include a tetraalkylene polyamine. Examples of the silicon compound having a plurality of basic nitrogen atoms (including nitrogen atoms such as amino groups) include: silane coupling agents having a plurality of basic nitrogen atoms such as 2- [ N- (2-aminoethyl) amino ] ethyltrimethoxysilane and 3- [ N- (2-aminoethyl) amino ] propyltriethoxysilane.

It should be noted that a silane coupling agent as a polyamine compound cannot be used as the above silane coupling agent.

From the viewpoint of satisfactory gas barrier performance and the viewpoint of water dispersion stability of the aqueous polyurethane resin, the amine value of the polyamine compound is preferably 100 to 1900mgKOH/g, more preferably 150 to 1900mgKOH/g, still more preferably 200 to 1900mgKOH/g, particularly preferably 200 to 1700mgKOH/g, and most preferably 300 to 1500 mgKOH/g. The amine value of the above polyamine compound is measured by the following method.

[ method for measuring amine value ]

Precisely weighing 0.5-2 g of sample (sample amount Sg). The precisely weighed sample was dissolved in 30g of ethanol. Bromophenol blue as an indicator was added to the resulting solution, and titration was performed with 0.2mol/L of an ethanolic hydrochloric acid solution (titer f). The point at which the color of the solution changed to a color between green and yellow was used as an end point, and the amine value was determined by the following equation 1 using the titration amount (AmL) at that time.

Formula 1 amine value is A × f × 0.2.2 0.2 × 56.10.10⁸/S[mgKOH/g]

In the aqueous polyurethane resin, the polyamine compound is preferably contained in an amount such that the molar ratio of the acid groups of the acid group-containing polyurethane resin to the basic nitrogen atoms of the polyamine compound (acid groups/basic nitrogen atoms) is 10/1 to 0.1/1, more preferably 5/1 to 0.2/1. When the acid group/basic nitrogen atom ratio is in the above range, the acid group of the acid group-containing polyurethane and the polyamine compound are appropriately subjected to a crosslinking reaction, and the coating layer can exhibit an oxygen barrier property.

The aqueous polyurethane resin is generally used in a state of being dispersed in an aqueous medium (aqueous dispersion).

Examples of the aqueous medium include: water, water-soluble or hydrophilic organic solvents, or mixtures thereof. Examples of the water-soluble or hydrophilic organic solvent include: alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; cellosolves; carbitols; nitriles such as acetonitrile.

The aqueous medium is preferably water or a substance containing water as a main component. The content of water in the aqueous medium is preferably 70% by mass or more, and more preferably 80% by mass or more.

The aqueous medium may or may not contain a neutralizing agent (base) that neutralizes the acid groups of the acid group-containing polyurethane resin. Typically comprising a neutralizing agent.

In the aqueous dispersion of the aqueous polyurethane resin, the average particle diameter of the dispersed particles (polyurethane resin particles) is not particularly limited, but is preferably 20 to 500nm, more preferably 25 to 300nm, and even more preferably 30 to 200nm, from the viewpoint of ensuring uniform dispersibility of the dispersed particles and other materials and dispersion stability of the barrier coating composition and well expressing gas barrier properties.

In the present specification, the average particle diameter is a value measured by a concentration type particle diameter analyzer (FPAR-10 manufactured by Otsuka Denshi Co., Ltd.) in a state of a solid content concentration of 0.03 to 0.3% by mass (diluted with water).

As the aqueous polyurethane resin, commercially available resins can be used, and resins produced by known production methods can also be used.

The method for producing the aqueous polyurethane resin is not particularly limited, and a general polyurethane resin aqueous technique such as acetone method or prepolymer method may be used. In the urethane-forming reaction, a urethane-forming catalyst such as an amine-based catalyst, a tin-based catalyst, or a lead-based catalyst may be used as necessary.

For example, the acid group-containing polyurethane resin can be produced by reacting a polyisocyanate compound, a polyhydroxy acid, and, if necessary, at least one of a polyol component and a chain extender component in an inert organic solvent such as a ketone such as acetone, an ether such as tetrahydrofuran, or a nitrile such as acetonitrile. More specifically, the aqueous dispersion of the acid group-containing polyurethane resin can be prepared by reacting a polyisocyanate compound, a polyhydroxy acid and a polyol component in an inert organic solvent (particularly a hydrophilic or water-soluble organic solvent) to produce a prepolymer having an isocyanate group at an end, neutralizing the prepolymer with a neutralizing agent, dissolving or dispersing the neutralized prepolymer in an aqueous medium, adding a chain extender component, reacting the neutralized prepolymer, and removing the organic solvent.

The aqueous polyurethane resin in the form of an aqueous dispersion can be prepared by adding the polyamine compound to the aqueous dispersion of the acid group-containing polyurethane resin obtained as described above and heating the mixture as necessary.

When heating, the heating temperature is preferably 30 to 60 ℃.

The total content of the aqueous urethane resin and the highly polar resin having an ethylene chain is preferably 0.5 to 30 parts by mass, more preferably 1 to 15 parts by mass in terms of solid content, based on 100 parts by mass of the barrier coating composition of the present invention.

The above-mentioned high-polar resin having an ethylene chain means a resin having an ethylene chain and the following high-polar functional group.

Examples of the highly polar functional group include: amino, ester, carboxyl, sulfone, cyano, thiol, hydroxyl, and the like.

Among them, from the viewpoint of good gas barrier properties, a hydroxyl group and a carboxyl group are preferable, and a hydroxyl group is more preferable.

The highly polar resin having an ethylene chain is preferably a copolymer of ethylene and a compound having a vinyl group.

Examples of the copolymer of ethylene and a compound having a vinyl group include: ethylene-vinyl alcohol copolymers, ethylene-acrylic acid copolymers, ethylene-vinyl acetate copolymers, ethylene-methyl methacrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate-maleic anhydride copolymers, and the like.

Among them, from the viewpoint of well expressing the gas barrier property, an ethylene-vinyl alcohol copolymer and an ethylene-acrylic acid copolymer are preferable, and an ethylene-vinyl alcohol copolymer is more preferable.

Preferably, the ethylene ratio in the highly polar resin having an ethylene chain is 0.5 to 30 mol%.

By adopting the above range of the ethylene ratio, the solubility to water and alcohol can be improved.

More preferably, the ethylene ratio in the highly polar resin having an ethylene chain is 1.0 to 15 mol%.

Preferably, the above-mentioned high-polarity resin having an ethylene chain has an ethylene chain in the main chain.

By having an ethylene chain in the main chain, the water resistance can be improved.

In the present invention, the "main chain" refers to the longest chain forming the polymer.

The degree of saponification of the highly polar resin having an ethylene chain is preferably 90 to 100%, more preferably 95 to 100%, and still more preferably 97 to 100%.

The average degree of polymerization of the highly polar resin having an ethylene chain is preferably 200 to 3000, more preferably 400 to 2000.

By adopting the above range of the average polymerization degree, the coating composition can be uniformly mixed with other components without excessively increasing the viscosity of the coating composition, and the gas barrier property of the coating layer and the peel strength with other layers can be appropriately provided.

The highly polar resin having an ethylene chain may be a commercially available resin, or a resin satisfying the above ethylene ratio, saponification degree, average polymerization degree, and the like may be produced by a known production method.

Preferably, the mass ratio (mass ratio of solid content) of the highly polar resin having an ethylene chain to 100 parts by mass of the aqueous urethane resin is 15 to 150 parts by mass.

By adopting the above range, both water resistance and gas barrier properties can be suitably achieved.

Examples of the silane coupling agent include RSiX₃(wherein R is an organic reactive group, and X is an alkoxy group).

Examples of the organic reactive group include groups having the following groups: amino, (meth) acrylic, epoxy, vinyl, mercapto, isocyanate, isocyanurate, and the like.

In the present specification, the (meth) acrylic group means both an acrylic group and a methacrylic group.

Examples of the alkoxy group include: methoxy, ethoxy, and the like.

Examples of the silane coupling agent include: a silane coupling agent having a vinyl group, a silane coupling agent having an epoxy group, a silane coupling agent having an amino group, a silane coupling agent having a mercapto group, a silane coupling agent having a (meth) acrylic group, a silane coupling agent having an isocyanate group, a silane coupling agent having an isocyanurate group, and the like.

Examples of the silane coupling agent having a vinyl group include: vinyltrimethoxysilane, vinyltriethoxysilane, and the like. Examples of the silane coupling agent having an epoxy group include: 2(3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethyldiethoxysilane, etc. Examples of the silane coupling agent having an amino group include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, etc. Examples of the silane coupling agent having a mercapto group include: 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and the like. Examples of the silane coupling agent having a (meth) acrylic group include 3-acryloxypropyltrimethoxysilane and the like. Examples of the silane coupling agent having an isocyanate group include 3-isocyanatopropyltriethoxysilane. Examples of the silane coupling agent having an isocyanurate group include tris- (trimethoxysilylpropyl) isocyanurate and the like.

These silane coupling agents may be used alone or in combination of two or more.

As the silane coupling agent, a substance reactive with other components in the barrier coating composition is preferably used. Among them, a silane coupling agent having an epoxy group is preferable.

The silane coupling agent having an epoxy group has good reactivity with the functional group of the aqueous urethane resin or the highly polar resin having an ethylene chain, and is excellent in reactivity with a vapor-deposited layer described later, and thus, the laminate strength and the gas barrier property can be suitably improved.

Preferably, the silane coupling agent is 1 to 30 parts by mass per 100 parts by mass of the barrier coating composition of the present invention.

Preferably, the barrier coating composition of the present invention contains a solvent. The solvent may be any solvent that can dissolve the aqueous urethane resin, the highly polar resin having an ethylene chain, and the silane coupling agent, and any solvent can be used, including aqueous and nonaqueous solvents.

As the solvent, a mixed solvent of water and a lower alcohol is preferably used.

Examples of the lower alcohol include: lower alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, and the like, and alcohols containing at least one of these can be preferably used.

The solvent is preferably 5 to 60 parts by mass, more preferably 20 to 50 parts by mass, per 100 parts by mass of the barrier coating composition of the present invention.

The barrier coating composition of the present invention may contain inorganic fine particles such as silica, talc, alumina, calcium carbonate, titanium dioxide, magnesium carbonate, clay, kaolin, etc., colloidal silica, a surfactant, etc., and these are commonly referred to as an antiblocking agent.

The barrier coating composition of the present invention is composed of the above composition, and therefore, can be suitably used for lamination of packaging materials and the like.

[ method for producing Barrier coating composition ]

The method for producing the barrier coating composition of the present invention is not particularly limited, and for example, a coating solution of a predetermined concentration can be prepared by adding the solvent to the aqueous polyurethane resin, the highly polar resin having an ethylene chain, and the silane coupling agent, and sufficiently stirring and mixing them at room temperature.

When the silane coupling agent is added, coagulation may occur when the silane coupling agent is added at one time, and therefore, the silane coupling agent is preferably added under slow stirring.

[ composite film ]

The composite film is also one of the present invention, and comprises at least a base film, a vapor deposition layer, and a coating layer in this order, wherein the coating layer is formed by applying the barrier coating composition.

The substrate film is not particularly limited as long as it is a film formed of a thermoplastic resin or the like having the ability to form a transparent film.

Examples of the resin used as the base film include: polyolefin resins such as polyethylene (low density, high density), ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-hexene copolymers, ethylene-octene copolymers, polypropylene, ethylene-vinyl acetate copolymers, ethylene-methyl methacrylate copolymers, and ionomer resins; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; amide resins such as nylon-6, m-xylylenediamine-adipic acid polycondensate and polymethymethacryimide, acrylic resins such as polymethyl methacrylate; styrene and acrylonitrile-based resins such as polystyrene, styrene-acrylonitrile copolymers, styrene-acrylonitrile-butadiene copolymers, and polyacrylonitrile; hydrophobic cellulose resins such as triacetylcellulose and diacetylcellulose; halogen-containing resins such as polyvinyl chloride, polyvinylidene fluoride, and teflon (registered trademark); hydrogen-bonding resins such as polyvinyl alcohol, ethylene-vinyl alcohol copolymers, and cellulose derivatives; engineering plastic resins such as polycarbonate resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, polyphenylene ether resins, polyethylene oxide resins (polyethylene oxide resins), and liquid crystal resins. These may be used alone or in combination of two or more.

Preferably, the side of the base film on which the vapor deposition layer and the coating layer are provided is subjected to a surface treatment such as a plasma treatment or a corona discharge treatment.

The thickness of the base film is not particularly limited, but is preferably 0.5 to 1000. mu.m, more preferably 1 to 500. mu.m, still more preferably 1 to 100. mu.m, and particularly preferably 1 to 50 μm.

The vapor deposition layer is preferably formed on the base film by a vacuum process such as a vacuum evaporation method, a sputtering method, or a plasma vapor deposition method (PVD method or CVD method) using an inorganic oxide.

Examples of the inorganic oxide include: and oxides such as metals including silicon, aluminum, lead, tin, iron, and manganese, and inorganic compounds containing one or more of these metals.

Among them, from the viewpoint of excellent adhesion to a coating layer formed by applying the barrier coating composition of the present invention, one or more vapor-deposition layers selected from the group consisting of silica and alumina are preferable.

The thickness of the vapor deposition layer is not particularly limited, but is preferably 0.1 to 500nm, more preferably 0.5 to 40 nm.

The coating layer can be formed by applying the barrier coating composition.

The coating method of the barrier coating composition is not particularly limited, and a roll coating method using a gravure roll or the like, a doctor blade method, an air knife/nozzle coating method, a bar coating method, a spray coating method, a dip coating method, a coating method combining these methods, and the like can be used.

The thickness of the coating layer is not particularly limited, but is preferably 0.01 to 5 μm, and more preferably 0.1 to 2 μm.

If the coating layer is thinner than 0.01 μm, high gas barrier properties may be difficult to obtain, but even if it exceeds 5 μm, the gas barrier properties may not be significantly improved.

The composite film of the present invention may have a printed layer.

The printing layer (printing layer for content display or decoration function) can be formed by printing an organic solvent type printing ink composition, a water-based printing ink composition, or the like conventionally used for flexible packaging by a gravure printing method or a flexographic printing method.

Examples of the organic solvent-based printing ink composition include: an aromatic/non-aromatic mixed organic solvent printing ink composition containing a pigment and a polyurethane resin, and an organic solvent printing ink composition disclosed in japanese patent laid-open publication No. h 01-261476 (an aromatic/non-aromatic mixed organic solvent printing ink composition containing a pigment, a polyurethane resin, and chlorinated polypropylene), japanese patent publication No. h 07-113098 (a non-aromatic organic solvent printing ink composition containing a pigment and a polyurethane resin), and japanese patent laid-open publication No. h 07-324179 (a non-aromatic/non-ketone organic solvent printing ink composition containing a pigment, a polyurethane resin, and a non-aromatic/non-ketone).

Examples of the aqueous printing ink composition include: and aqueous printing ink compositions disclosed in, for example, Japanese patent application laid-open No. H06-155694 (aqueous printing ink compositions containing a pigment, an acrylic binder resin, and a hydrazine-based crosslinking agent), Japanese patent application laid-open No. H06-206972 (aqueous printing ink compositions containing a pigment, water, and a polyurethane-based binder resin), and the like.

Recently, as the environmentally friendly ink, an aqueous type printing ink composition or an organic solvent type printing ink composition of a type in which an aromatic or ketone organic solvent is not used as much as possible is used, and these inks can be suitably used in the present invention.

The barrier composite film of the present invention may further include other functional layers such as an ultraviolet shielding layer, an antibacterial layer, an adhesive layer, and a sealant layer.

Preferably, the adhesive layer is formed between the base film and the vapor deposition layer or between the coating layer and the sealant layer.

As the adhesive layer, an adhesive composition conventionally used for manufacturing a composite laminate film for packaging can be appropriately selected and formed by using various coating methods and apparatuses.

Examples of the adhesive composition include: various adhesives such as urethanes, polyesters, and acrylics; and various adhesives such as titanium-based adhesives, isocyanate-based adhesives, imine-based adhesives, and polybutadiene-based adhesives.

The sealant layer is a hot melt sheet conventionally used for flexible packaging, and examples thereof include: polyethylene films, polypropylene films, and the like.

The sealant layer may be a layer obtained by laminating a hot-melt polymer such as low-density polyethylene, ethylene-vinyl acetate copolymer, or polypropylene polymer in a molten state and cooling and molding the laminate into a film shape.

[ method for producing composite film ]

The method for producing the composite film of the present invention is not particularly limited, and a conventional method can be appropriately selected and used.

For example, the following methods (a) to (d) can be mentioned.

(a) After a vapor deposition layer is formed on a base film (the base film may be a laminate film having a vapor deposition layer) by the above-described method, the above-described barrier coating composition and adhesive composition are sequentially applied, and then a sealant layer is laminated, thereby obtaining a composite film.

(b) After a vapor deposition layer is formed on a base film (the base film may be a laminate film having a vapor deposition layer) by the above-described method, the above-described adhesive composition, barrier coating composition, adhesive composition are sequentially applied, and then a sealant layer is laminated, thereby obtaining a composite film.

(c) After a vapor deposition layer is formed on a base film (the base film may be a laminated film having a vapor deposition layer) by the above-described method, an ink composition is first printed to form a printed layer, and then the above-described adhesive composition, barrier coating composition, adhesive composition are sequentially coated, and then a sealant layer is laminated, thereby obtaining a composite film.

(d) The barrier composite film is obtained by forming a vapor deposition layer on a base film (the base film may be a laminated film having a vapor deposition layer) by the above-described method, then applying the adhesive composition, the barrier coating composition, and the adhesive composition in this order, then printing the ink composition to form a printed layer, and then laminating a sealant layer.

As a method for applying the adhesive composition, a roll coating method using a gravure roll or the like, a doctor blade method, an air knife/nozzle coating method, a bar coating method, a spray coating method, a dip coating method, a coating method combining these methods, and the like can be used.

In order to form the printing layer, a gravure printing method or a flexographic printing method can be generally used.

In the composite film of the present invention, the thickness (after drying) of the adhesive layer is preferably 2 to 3 μm.

When the thickness of the adhesive layer is less than 2 μm, the adhesiveness of the coating layer to other layers may be deteriorated, while when the thickness is more than 3 μm, the adhesiveness may not be increased by the increase of the film thickness, and when the composite film is used as a packaging bag, good workability may not be obtained.

Note that, when a coating film having a film thickness within the above range cannot be obtained by one coating, it may be necessary to coat a plurality of times.

When other functional layers are provided, it is also possible to produce a desired barrier composite film by combining the above-described methods (a) to (d) with a good apparatus/method for providing each functional layer.

Effects of the invention

The barrier coating composition of the present invention is composed of the above-mentioned composition, and therefore, a composite film excellent in lamination strength, seal strength, water vapor barrier property and oxygen barrier property under boiling conditions and under wet conditions can be obtained.

The composite film of the present invention can be suitably used as a barrier film, a packaging material, or the like.

Detailed Description

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" represents "% by mass" and "parts" represents "parts by mass".

(Barrier coating composition)

< aqueous polyurethane resin >

TAKELAC WPB-341 (30% solid content, glass transition temperature 115 ℃ C., manufactured by Mitsui chemical Co., Ltd.)

< highly polar resin having ethylene chain >

EXCEVAL RS-2117 (average polymerization degree 1700, saponification degree 97.5-99.0%, ethylene ratio 3.0 mol%, main chain with ethylene chain, Kao Leli)

SOARNOL SG525 (saponification degree of 99.0-100%, ethylene ratio of 26 mol%, main chain having ethylene chain, manufactured by Nippon synthetic chemical industries Co., Ltd.)

< highly polar resin having no ethylene chain >

GOHSENOL NH-18 (average polymerization degree of 1800, saponification degree of 98.0-99.0%, ethylene ratio of 0 mol%, manufactured by Nippon synthetic chemical industries Co., Ltd.)

< silane coupling agent >

KBM-403 (3-glycidoxypropyltrimethoxysilane, available from shin-Etsu chemical Co., Ltd.)

< solvent >

Deionized water

Isopropanol (I-propanol)

< preparation of aqueous solution of RS-2117 >

To 90 parts by mass of purified water, EXCEVAL RS-211710 parts by mass was added, and the mixture was stirred at 95 ℃ for about 2 hours to obtain an RS-2117 aqueous solution (solid content: 10%).

< preparation of SG525 solution >

A mixed solvent of 44.2 parts by mass of purified water and 71.996 parts by mass of n-propanol (NPA) was added with SOARNOL SG52515 parts by mass, 13 parts by mass of 30% hydrogen peroxide water, and FeSO₄0.004 portion by mass, heated to 80 ℃ with stirring, and reacted for 2 hours.

Then, cooled and catalase was added to 3000ppm, and residual hydrogen peroxide was removed to obtain an almost transparent SG525 aqueous solution (solid content 15%).

< preparation of NH-18 aqueous solution >

GOHSENOL NH-1810 (parts by mass) was added to 90 parts by mass of purified water, and the mixture was stirred at 95 ℃ for about 2 hours to obtain an NH-18 aqueous solution (solid content: 10%).

< production of silica vapor deposition PET >

An adhesive layer having a thickness of 0.1 μm was formed by applying a mixture of an isocyanate compound ("CORONATE L" manufactured by NIPPON POLYURETHANE INDUSTRIAL CO., LTD.) and a saturated polyester ("BYRON 300" manufactured by TOYOBO SPINNING CO., LTD.) at a mass ratio of 1:1 to one surface of a PET film (E5100, thickness 12 μm, manufactured by TOYOBO SPINK., LTD.) and drying the mixture, and then, using a vacuum vapor deposition apparatus, the adhesive layer was 1 × 10^-5The silica was evaporated by heating under vacuum of Torr to form a silica vapor-deposited layer with a thickness of 20nm on the adhesive layer, to obtain silica vapor-deposited PET.

< preparation of alumina vapor deposition PET >

A mixture of an isocyanate compound ("CORONATE L" manufactured by NIPPON POLYURETHANE INDUSTRIAL CO., LTD.) and a saturated polyester ("BYRON 300" manufactured by TOYOBO SPINNING CO., LTD.) in a mass ratio of 1:1 was applied to one surface of a PET film (E5100, thickness 12 μm, manufactured by TOYOBO SPINNING CO., LTD.) and dried to form a film having a thickness of 0.1 μmm, then evaporating the aluminum using a vacuum vapor deposition apparatus, supplying oxygen using a gas flow control apparatus, at 1 × 10^-4Vapor deposition was carried out under Torr to form an alumina vapor deposition layer with a thickness of 20nm on the adhesive layer, to obtain alumina vapor deposition PET.

(example 1)

While stirring TAKELAC WPB-34122.2 parts by mass, 28.5 parts by mass of an RS-2117 aqueous solution having a solid content of 10%, 30.9 parts by mass of deionized water, and 18.1 parts by mass of isopropyl alcohol were added, and then 0.3 part by mass of KBM-403 was added, followed by sufficient stirring and mixing at room temperature to obtain coating composition 1.

The silica vapor-deposited layer face of the silica vapor-deposited PET prepared above was coated with the coating composition 1 using a No.6 wire bar, dried by a dryer, and then aged at 60 ℃ for 1 day.

Coating obtained with No.4 wire bar (coating weight 0.8g/m after drying)²) A polyurethane adhesive (TAKELACA515/TAKENATEA50, 30% solid content, manufactured by Mitsui chemical Co., Ltd.) was coated thereon, a sealant film (RXC-22, 60 μm thick, manufactured by Mitsui chemical Toxocello Co., Ltd.) was laminated thereon, and aging treatment was performed at 40 ℃ for 3 days to obtain a composite film.

(example 2)

A composite film was obtained in the same manner as in example 1, except that the substrate film was changed to the alumina vapor deposition PET produced above.

(example 3, comparative examples 1 to 3)

Coating compositions 2 to 5 were prepared in the compounding ratios shown in Table 1, and composite films were obtained in the same manner as in example 1.

Comparative examples 4 to 5

A composite film was obtained in the same manner as in examples 1 to 2, except that the coating composition was not used.

[ Table 1]

[ evaluation ]

< measurement of lamination Strength (N/15mm) >

(1) General conditions

(drying conditions)

Each of the composite films of examples 1 to 3 and comparative examples 1 to 5 was cut into a 15mm width.

The lamination strength was determined by measuring T-type peel strength at a peel speed of 300mm/min using a peel tester (manufactured by Antand Seiko Seisakusho K.K.). The results are shown in Table 2.

(boiling conditions)

The laminate strength was measured in the same manner as in the drying condition except that each of the composite films of examples 1 to 3 and comparative examples 1 to 5 was cut to a width of 15mm after being immersed in hot water at 90 ℃ for 30 minutes. The results are shown in Table 2.

(2) Water condition

(drying conditions)

Each of the composite films of examples 1 to 3 and comparative examples 1 to 5 was cut into a 15mm width.

Absorbent cotton after absorbing water was placed on the release surface of each sample piece, and the T-type release strength was measured at a release rate of 300mm/min by using a release tester (manufactured by antan seiko corporation) to determine the lamination strength. The results are shown in Table 2.

(boiling conditions)

The laminate strength was measured in the same manner as in the drying condition except that each of the composite films of examples 1 to 3 and comparative examples 1 to 5 was cut to a width of 15mm after being immersed in hot water at 90 ℃ for 30 minutes. The results are shown in Table 2.

The numbers in table 2 are indicated by F, and the composite film was broken but not peeled at the strength of the numbers.

< seal Strength (kg/15mm) >

The composite films of examples 1 to 3 and comparative examples 1 to 5 were formed into bags by using a pulse SEALER (manufactured by Fuji IMPULSE SEALER Co., Ltd.), and the seal strength was measured at a peeling speed of 300mm/min by using a peel tester (manufactured by Anta Seiko Co., Ltd.). The results are shown in Table 2.

The numbers in table 2 are indicated by F, and the composite film was broken but not peeled at the strength of the numbers.

<Oxygen transmission rate (oxygen transmission rate) (cc/m)²Day/atmosphere pressure)>

The composite films (used for the oxygen transmission rate test) of examples 1 to 3 and comparative examples 1 to 5 were left to stand at 25 ℃ and 90% RH for 72 hours, and then the oxygen transmission rate (OTR value) was measured according to JIS K7126B using an oxygen transmission rate measuring apparatus (product name: OX-TRAN1/50, manufactured by Mocon corporation).

The measurement was performed at 25 ℃ and 90% RH. The results are shown in Table 2.

<Water vapor transmission rate (g/m)²Day)>

The water vapor transmission rate (WVTR value) of the composite films (for the water vapor transmission rate test) of examples 1 to 3 and comparative examples 1 to 5 was measured as follows according to JIS Z0222.

For each of the composite films of examples 1 to 3 and comparative examples 1 to 5, a bag having the same volume was made of a composite film having a size of 10cm × 10cm, and 15g of calcium chloride was filled in the bag and sealed by fusion. The bag was placed in a constant temperature and humidity apparatus at 40 ℃ and 90% RH, and the mass was measured every 5 days. The water vapor transmission rate was calculated from the slope of the regression line of the elapsed time after day 3 and the bag mass. The results are shown in Table 2.

[ Table 2]

In examples 1 to 3 in which composite films were produced using the barrier coating composition of the present invention, the laminate strength, seal strength, water vapor barrier property and oxygen barrier property were excellent under boiling conditions and water conditions.

On the other hand, comparative example 1, in which the composite film was produced using coating composition 3 containing no highly polar resin having an ethylene chain, had poor gas barrier properties, comparative example 2, in which the composite film was produced using coating composition 4 containing a highly polar resin having no ethylene chain, had poor layer pressure under wet conditions, and comparative example 3, in which the composite film was produced using coating composition 5 containing no silane coupling agent, had poor lamination strength under wet conditions.

In comparative examples 4 and 5, in which composite films were produced without using the coating composition, the laminate strength, seal strength, water vapor barrier property and oxygen barrier property were inferior under boiling conditions and water conditions.

Industrial applicability

The barrier coating composition of the present invention is composed of the above-mentioned composition, and therefore, a composite film excellent in lamination strength, seal strength, water vapor barrier property and oxygen barrier property under boiling conditions and under wet conditions can be obtained.

The composite film of the present invention can be suitably used as a barrier film, a packaging material, or the like.