JP2005132994A - Gas barrier film laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas barrier packaging material enabling sight through of contents because of excellent transparency, capable of using a metal detector at the occasion of inspection of contents, not using such causative substance as to pollute the environment as a matter of course, having high gas barrier property under high temperature and high humidity, continuously keeping excellent gas barrier property after boiling treatment or retort sterilization treatment and being optimal as a packaging material. <P>SOLUTION: The gas barrier film laminate is obtained by applying a polymer solution mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit onto one side or both sides of a film substrate composed of a plastic material and heat-drying the coating and laminating the resultant coated film layer having a gas barrier property. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a film laminate for packaging used for packaging foods, beverages, non-foods such as pharmaceuticals and electronic components, and has a particularly high gas barrier property and blocks contents from oxygen and water vapor in the atmosphere. And it is related with the gas barrier film laminated body which enabled it to suppress the deterioration and alteration.

  In recent years, packaging materials used for packaging foods and beverages and non-food products such as pharmaceuticals and electronic components suppress the deterioration of contents and retain their functions and properties, so that oxygen, water vapor, In addition, it is necessary to prevent the influence of the gas that alters the contents, and it is required to have a gas barrier property that blocks these gases.

Therefore, conventionally, as a packaging material having a gas barrier property, a metal foil made of a metal typified by aluminum or the like, a metal vapor-deposited film having a metal vapor-deposited thin film, a polyvinyl alcohol and an ethylene vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile A plastic film made of such plastics, or a plastic film coated with these plastic materials has been mainly used.
Japanese Patent Laid-Open No. 6-164591

  However, when used as a packaging material, metal foil and metal vapor-deposited film are excellent in gas barrier properties, but the contents cannot be confirmed through it, metal detectors cannot be used for inspection, and disposal after use. Has to be treated as non-combustible material. Gas barrier plastic films and films coated with them are highly temperature and humidity dependent and cannot maintain a high level of gas barrier properties. Especially, films made of polyvinylidene chloride can be used as a raw material for hazardous substances during disposal and incineration. There is a problem such as possible. In other words, it can be said that the gas barrier packaging materials currently used mainly have various problems due to their advantages and disadvantages.

  As a packaging material for solving such problems, a vapor deposition layer made of an inorganic oxide compound is used as a first layer, and at least one of a water-soluble polymer and one or more types of metal alkoxides, metal alkoxide hydrolysates, or tin chloride. A gas barrier packaging material is proposed in which a gas barrier coating is formed by applying a coating agent mainly composed of an aqueous solution containing water or a mixed solution of hydroalcohol, followed by heating and drying, and then laminating these layers on a film substrate in sequence. (See Patent Document 1). This gas barrier packaging material exhibits high gas barrier properties, has water resistance and moisture resistance, and can withstand a certain amount of external stress. However, the second coating layer of the gas barrier packaging material has a hydrogen bond between the metal alkoxide hydrolyzate and the water-soluble polymer having a hydroxyl group, so that it can be used for packaging materials that require treatment such as boil and retort sterilization. Since the laminated coating layer swells, the gas barrier properties are slightly deteriorated.

  The present invention has been made to solve the above-described problems of the prior art, and has a high gas barrier property under high temperature and high humidity as well as not using causative substances that pollute the environment. In addition, an object of the present invention is to provide a gas barrier film laminate that is optimal as a packaging material and that maintains an excellent gas barrier property even after sterilization with boil or retort.

  In order to solve the above problems, the invention according to claim 1 is a polymer mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit on one or both sides of a film base made of a plastic material. A gas barrier film laminate comprising a gas barrier coating layer formed by applying a solution and drying by heating.

  The invention according to claim 2 is a polymer solution mainly comprising a copolymer having a vapor-deposited layer made of an oxidized inorganic compound and an acrylonitrile-vinyl alcohol unit on one side or both sides of a film base made of a plastic material. A gas barrier film laminate, in which a gas barrier coating layer obtained by coating and drying by heating is sequentially laminated.

  Furthermore, the invention according to claim 3 is the gas barrier film laminate according to claim 1 or 2, wherein the polymer solution is at least an alkoxysilane compound or a hydrolyzate thereof, a silane coupling agent or a hydrolysis thereof. It includes any of the objects.

  Furthermore, the invention according to claim 4 is the gas barrier film laminate according to claim 2 or 3, wherein the acrylic polyol, isocyanate, and silane cup are interposed between the film substrate and the vapor-deposited layer comprising the oxidized inorganic compound. A primer layer composed of a primer agent combined with a ring agent is laminated.

  Furthermore, the invention according to claim 5 is the gas barrier film laminate according to any one of claims 1 to 4, wherein a heat seal layer is further laminated on the gas barrier coating layer. .

  The barrier film laminate of the present invention has high gas barrier properties, is excellent in water resistance and moisture resistance, and continues to maintain the high gas barrier properties even after boil / retort sterilization treatment. In addition, the adhesion of the gas barrier coating layer to the film substrate and the vapor-deposited layer made of an inorganic oxide compound is also good, and by further post-processing such as printing, dry lamination, melt extrusion lamination, thermocompression lamination, food In addition, it is possible to provide a highly practical packaging material used for packaging in a wide range of fields such as non-food such as beverages, pharmaceuticals and electronic components.

  Hereinafter, the present invention will be described in detail with reference to the drawings. 1 and 2 show a cross-sectional configuration of the gas barrier film laminate of the present invention.

  The gas barrier film laminate shown in FIG. 1 is obtained by applying a polymer solution mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit to one side of a film substrate 1 made of a plastic material, and drying by heating. The coating layer 2 is laminated.

  On the other hand, the gas barrier film laminate shown in FIG. 2 is a co-polymer having a primer layer 3 made of a primer agent, a vapor-deposited layer 4 made of an inorganic oxide, and an acrylonitrile-vinyl alcohol unit on one side of a film substrate 1 made of a plastic material. A polymer solution containing a polymer as a main ingredient is applied, and a gas barrier coating layer 2 formed by heating and drying is sequentially laminated.

The film substrate 1 is made of a plastic material and is preferably transparent. Specifically, polyester films made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyolefin films made of polyethylene, polypropylene, etc., polystyrene films, polyamide films such as 6,6-nylon, polycarbonate films, polyacrylonitrile An engineering plastic film such as a film or a polyimide film is used. These may be stretched or unstretched. Among these, those having mechanical strength and dimensional stability are preferable, and among them, a film arbitrarily stretched in the biaxial direction is preferably used. In consideration of gas barrier properties, filling suitability, texture, easy disposal, and price, when used as a packaging material, a biaxially stretched polyamide film or polyester film is particularly preferable.

  The thickness of the film substrate 1 is not particularly limited. However, in consideration of suitability and processability as a packaging material, it is practically in the range of 3 to 200 μm, and generally 6 to 30 μm. .

  Further, the surface of the film substrate 1 may be subjected to treatment such as antistatic treatment with various known additives and stabilizers such as antistatic agents, plasticizers, lubricants, antioxidants, etc. May be subjected to corona treatment, plasma treatment, ozone treatment or the like as pretreatment for improving adhesion. Further, chemical treatment or solvent treatment may be performed. In particular, the plasma treatment is also preferable in order to firmly adhere the vapor deposition layer 4 made of an oxidized inorganic compound, which will be described later, onto the film substrate 1.

  Further, when a primer layer 3 is further provided between the film substrate 1 and the vapor deposition layer 4 made of the oxidized inorganic compound as shown in FIG. 2, the vapor deposition layer 4 made of the oxidized inorganic compound is uniformly formed, and the gas barrier In addition, the adhesiveness is further improved, and the adhesion is greatly improved. In particular, when a boil / retort sterilization treatment or the like is performed when used as a packaging material, it is preferable to provide a primer layer in this manner.

  The primer layer 3 has a urea bond by a reaction between an organic polymer obtained by a two-component reaction of a polyol such as acrylic polyol, polyvinyl acetal, polyester polyol, and polyurethane polyol with an isocyanate compound, or a reaction of a polyisocyanate compound and water. Primers mainly composed of organic compounds, polyethyleneimine or derivatives thereof, polyolefin emulsions, polyimides, melamines, phenols, inorganic silicas such as organically modified colloidal silica, and organic silane compounds such as silane coupling agents and hydrolysates thereof. It may be provided by an agent, but particularly when it is provided by a primer agent that is a combination of an acrylic polyol, an isocyanate compound, and a silane coupling agent, adhesion is improved, for example, oxidation Even without deposition layer made of a machine compounds, so it exhibits high gas barrier properties. In general, the thickness is desirably provided in a range of 0.005 to 5 μm, more preferably in a range of 0.01 to 1.0 μm after drying. When the thickness is 0.01 μm or less, it is difficult to obtain a uniform coating film from the viewpoint of coating technique, and conversely, when it exceeds 1 μm, it is uneconomical.

  On the other hand, the vapor deposition layer 4 made of an oxidized inorganic compound in FIG. 2 is made of an oxide such as silicon, aluminum, titanium, zirconium, tin, magnesium, or a composite thereof, and includes a vacuum vapor deposition method, a sputtering method, and a plasma vapor phase growth method. Etc. are formed by a vacuum process. In particular, the deposited layer made of oxide of aluminum oxide is colorless and transparent. When used in combination with a transparent film substrate, the contents can be seen through at the time of packaging, and a metal detector can be used for inspection of the contents. In addition, it exhibits excellent water resistance against boil and retort sterilization, and can be used for a wide range of applications.

  The film thickness of the vapor-deposited layer 4 made of the oxidized inorganic compound can be variously selected depending on the application and the film thickness of the gas barrier coating layer 5 provided thereon, but is preferably in the range of several tens to 5,000 mm. However, if it is 50 mm or less, there may be a problem in the continuity of the thin film, and if it exceeds 3000 mm, cracks are likely to occur and the flexibility may be lowered.

  On the other hand, the gas barrier coating layers 2 and 5 constituting the gas barrier film laminate of the present invention are coated with a polymer solution mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit as described above, and dried by heating. It is obtained by. In general, a film obtained by applying a polymer solution mainly composed of polyvinyl alcohol and heating and drying is excellent in gas barrier properties, but has high humidity dependency. On the other hand, when a film is formed with a polymer solution mainly composed of acrylonitrile units copolymerized at an appropriate ratio as a comonomer as in the present invention, a high barrier film layer having low humidity dependency is formed. Is possible. Moreover, in order to further improve water resistance and moisture resistance, it is preferable to use an alkoxysilane compound or a hydrolyzate thereof, a silane coupling agent or a hydrolyzate thereof in combination.

  Moreover, it is preferable that an acrylonitrile vinyl alcohol unit occupies 70 mol% or more in a copolymer. Further, other ethylene or various α-olefin units may be copolymerized. Further, the vinyl alcohol unit is preferably contained in the copolymer in an amount of 40 mol% or more, and if it is less than that, the gas barrier property is lowered.

  The above-mentioned alkoxysilane compound, its hydrolyzate, silane coupling agent and its hydrolyzate improve the water resistance and moisture resistance of the film, but the volume during condensation in the hydrolyzate of alkoxysilane and silane coupling agent. Accompanying the strain due to the reduction, the coating layer made of the same is easily cracked, and it becomes very difficult to form a thin, transparent and uniform condensate coating. On the other hand, by using together with the above-described polymer copolymer as in the present invention, insolubilization of the coating is improved, flexibility is imparted to the formed coating layer, and generation of cracks can be prevented. In addition, a highly water-resistant gas barrier performance that does not deteriorate even when harsh processing such as sterilization is performed can be realized.

  However, when a polymer copolymer is added in combination, even if it appears to be uniform visually, it is microscopically separated into a hydrolyzate of alkoxysilane or silane coupling agent and a polymer part. In many cases, gas barrier packaging materials tend to be barrier holes. Therefore, in such a case, by further adding a polymer having a hydroxyl group, the hydrolyzate of alkoxysilane or silane coupling agent is well dispersed between the polymer part and the formed film is high. Gas barrier properties can be expressed. Moreover, when this film is laminated on a vapor-deposited layer composed of an inorganic oxide compound, the gas barrier film laminate in which these are laminated has higher gas barrier properties, water resistance, and moisture resistance than the individual effects obtained by the respective layers. Will show.

  The copolymer in the gas barrier coating layer according to the present invention is obtained, for example, by saponifying acrylonitrile-vinyl acetate, and several tens% of acetyl groups are left from the so-called partial saponification in which several acetyl groups remain. It includes even fully saponified copolymers that remain only. Further, the molecular weight of the copolymer is preferably 1000 or more from the viewpoint of the film forming property of the polymer solution. However, it can be said that a high molecular weight copolymer having a high degree of saponification and a high degree of polymerization is generally preferred since water resistance and moisture resistance are recognized and gas barrier properties are excellent.

  The thickness after coating / heating and drying of a polymer solution mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit is not particularly limited. However, if the thickness exceeds 50 μm, cracks tend to occur. It is desirable to set it to -50 micrometers.

As a method for forming a gas barrier coating layer with a polymer solution, a normal coating method can be used. For example, dipping method, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, silk screen, spray coating, gravure offset method and the like can be used. Using these coating methods, a polymer solution mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit is directly applied on a vapor deposition layer or a film substrate. Heating and drying methods for the applied gas barrier coating include hot air drying, hot roll drying, high frequency induction heating, infrared irradiation, UV irradiation, etc., that is, any method that heats the coating and eliminates the solvent. Any of these may be used, or two or more of these may be combined.

  As mentioned above, although the structure of this invention was demonstrated, a packaging material with higher practicality can be provided by providing a heat-seal layer in the above-mentioned gas-barrier film layers 2 and 5 side. This heat seal layer is used for an adhesive part when forming a bag-like package, for example, polyethylene, linear polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer. It is formed of a plastic material such as a polymer, ethylene-methacrylic acid, an ester copolymer, an ethylene-acrylic acid copolymer, an ethylene-acrylic acid ester polymer, and a metal cross-linked product thereof. The thickness is appropriately determined according to the purpose, but is generally in the range of 15 to 200 μm. In consideration of usage as a packaging material, a heat seal layer may be provided on the film substrate side.

  As a method of forming the heat seal layer, a dry laminate method in which a film-like material made of the above plastic material is bonded using a two-component reaction curable adhesive, a non-solvent laminate method in which a non-solvent adhesive is bonded, Any of the extrusion laminating methods and the like can be formed by a known laminating method by melting and melting the obtained plastic material, extruding it into a curtain, and laminating it.

  Moreover, it is also possible to laminate | stack a printing layer on a gas barrier film layer as needed, and it is also possible to laminate | stack several resin layers via an adhesive agent. Moreover, you may laminate | stack the several resin layer through a printing layer, a heat seal layer, and an adhesive agent also on the other surface of the film base material 1. FIG.

  Hereinafter, the gas barrier film laminate of the present invention will be described with specific examples.

  Acrylonitrile-vinyl in which acrylonitrile and vinyl alcohol are adjusted in the following ratios (A) and (B) with a gravure coater on two 12 μm thick PET film bases with corona treatment on the surface. After applying a polymer solution mainly composed of a copolymer having an alcohol unit, it was dried in a heat dryer at 100 ° C. for 1 minute to form a gas barrier coating layer having a thickness of about 2.0 μm. Example 1 Gas barrier film laminates A and B according to the above were obtained.

(A) Acrylonitrile / vinyl alcohol = 50/50 (mol%)
(B) Acrylonitrile / vinyl alcohol = 30/70 (mol%)

  A polymer solution mainly composed of a copolymer having an ethylene-vinyl alcohol unit in which ethylene and vinyl alcohol are adjusted at the following ratio (C), and a polymer solution mainly composed of polyvinyl alcohol shown in (D) below Were used, and film laminates C and D according to Example 2 for comparison were obtained under the same conditions as in Example 1 except that a gas barrier coating layer was formed.

(C) Ethylene / vinyl alcohol = 50/50 (mol%)
(D) Polyvinyl alcohol (completely saponified product)

On two film substrates made of PET having a thickness of 12 μm subjected to corona treatment, glycidyl polyacrylate (10%) and hydroxyethyl polyacrylate (1
Primer consisting of acrylic polyol containing 5%), tetraethoxysilane (15%) and silane monomer (5%), isocyanate curing agent (5%) mixed ethyl acetate (20%), butyl acetate solution (30%) The primer was provided by coating the agent so that the film thickness was about 0.1 μm. Next, an evaporation layer having a thickness of 200 mm was formed on the primer layer by vacuum evaporation using an electron beam heating method using aluminum oxide as an evaporation source. And finally, a polymer solution mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit in which acrylonitrile and vinyl alcohol are adjusted in the following ratio (E) and a hydrolyzate of tetraethoxysilane (TEOS), After applying each of a polymer solution mainly composed of an acrylonitrile-vinyl alcohol unit in which acrylonitrile and vinyl alcohol are adjusted at the following ratio (F) and a hydrolyzate of an epoxy silane coupling agent, the mixture is applied to a dryer at 100 ° C. Was dried for 1 minute to form a gas barrier film layer having a thickness of about 1.0 μm, and gas barrier film laminates E and F according to Example 3 were obtained.

(E) Hydrolysis product of acrylonitrile / vinyl alcohol = 30/70 (mol%) + tetraethoxysilane (TEOS) (F) Hydrolysis of acrylonitrile / vinyl alcohol = 30/70 (mol%) + epoxysilane coupling agent Stuff

  Example 4 for comparison under the same conditions as in Example 1 except that each of the polymer solutions mainly comprising a mixture shown in (G) and (H) below was used to form a gas barrier coating layer. The film laminated bodies G and H which concern on were obtained.

(G) Hydrolyzate of polyvinyl alcohol + tetraethoxysilane (H) Hydrolyzate of polyvinyl alcohol + epoxysilane coupling agent Gas barrier film laminate (A, B, E, F) and film laminate (C, D) , G, H) is laminated with a non-stretched polypropylene (CPP) film having a thickness of 70 μm using an adhesive (A-515 / A-50 manufactured by Mitsui Takeda Chemical Co., Ltd.) by a dry laminating method. A film laminate (a, b, e, f)) and a film laminate (c, d, g, h) were prepared. Oxygen permeability after subjecting each obtained film laminate (a to h) to retorting treatment at 121 ° C. for 30 minutes was measured using an oxygen permeability measuring device (OXTRAN-2 / 20 manufactured by Modern Control). , And measured in an atmosphere of 30 ° C. and 70% RH. Table 1 shows the oxygen permeability measured before the retort treatment and the laminate strength data after the retort treatment.

表１より、本発明に係るガスバリアフィルム積層体ａ、ｂ、ｅ、ｆは、比較のために作成したフィルム積層体ｃ、ｄ、ｇ、ｈに比べ、ガスバリア性において有意差があることが認められる。またレトルト処理後の酸素透過度に関しては、比較のためのフィルム積層体ではレトルト後に酸素透過度が高くなってしまうのに対し、本発明のガスバリアフィルム積層体ではそれ程高くはならず、バリア性が大きく劣化せずに高いバリア性を維持していることが分かる。

From Table 1, it is recognized that the gas barrier film laminates a, b, e and f according to the present invention have a significant difference in gas barrier properties as compared with the film laminates c, d, g and h prepared for comparison. It is done. In addition, regarding the oxygen permeability after retorting, the oxygen permeability becomes high after retorting in the film laminate for comparison, whereas the barrier property is not so high in the gas barrier film laminate of the present invention. It can be seen that a high barrier property is maintained without significant deterioration.

It is a section explanatory view of the gas barrier film layered product concerning one embodiment of the present invention. It is a section explanatory view of a gas barrier film layered product concerning other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material 2, 5 ... Gas barrier film layer 3 ... Primer layer 4 ... Deposition layer

Claims (5)

  Applying a polymer solution mainly composed of a copolymer having an acrylonitrile-vinyl alcohol unit to one or both sides of a film substrate made of a plastic material, and laminating a gas barrier coating layer formed by heating and drying. A gas barrier film laminate.   A gas barrier property formed by applying a polymer solution mainly composed of a vapor-deposited layer composed of an oxidized inorganic compound and a copolymer having an acrylonitrile-vinyl alcohol unit on one side or both sides of a film substrate made of a plastic material, and drying by heating. A gas barrier film laminate comprising a coating layer and a laminate.   The gas barrier film laminate according to claim 1 or 2, wherein the polymer solution contains at least one of an alkoxysilane compound or a hydrolyzate thereof, a silane coupling agent or a hydrolyzate thereof.   A primer layer composed of a primer agent that is a combination of an acrylic polyol, an isocyanate, and a silane coupling agent is laminated between the film base material and the vapor deposition layer made of the oxidized inorganic compound. The gas barrier film laminate according to claim 2 or 3.   The gas barrier film laminate according to any one of claims 1 to 4, wherein a heat seal layer is further laminated on the gas barrier coating layer.

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