JP3221221B2 - Gas barrier laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas barrier laminate used in the field of packaging foods, pharmaceuticals and the like.

[0002]

2. Description of the Related Art In recent years, packaging materials used for packaging foods, pharmaceuticals, and the like have been used in order to suppress deterioration of contents, especially oxidation and deterioration of proteins and oils and fats in foods, and to maintain taste and freshness. In the case of medicines that need to be handled under aseptic conditions, the deterioration of the active ingredients is suppressed and the effects of oxygen, water vapor, and other gases that deteriorate the contents of the packaging material are prevented in order to maintain the efficacy. It is required to have a gas barrier property for blocking these gases.

[0003] For this reason, gas barrier properties such as polyvinyl alcohol (hereinafter referred to as PVA), ethylene vinyl alcohol copolymer (EVOH), or polyvinylidene chloride resin (hereinafter referred to as PVDC) are generally said to be relatively high. A packaging film used as a packaging material as a gas barrier laminate by laminating or coating a polymer resin composition has been generally used. Further, a metal-deposited film obtained by vapor-depositing a metal or metal compound such as Al on a suitable polymer resin composition (even a resin that does not have a high gas barrier property by itself), or recently silicon monoxide (SiO) A vapor-deposited film formed by forming a silicon oxide (SiO _x ) thin film or a magnesium oxide (MgO) thin film on a substrate made of a polymer material having transparency by vapor deposition or the like has been developed. It has better gas barrier properties than a gas barrier material composed of a polymer resin composition, has less deterioration under high humidity, and packaging films used for packaging materials have begun to be generally used.

[0004]

However, the above-mentioned PV
A, The gas barrier laminate using the EVOH-based polymer resin composition has a large temperature dependency and a large humidity dependency, and therefore has a reduced gas barrier property at high temperature or high humidity. In addition, depending on the use of the packaging, boiling treatment or retort treatment may significantly reduce gas barrier properties. The gas barrier laminate using a PVDC-based polymer resin composition has a small dependence on humidity, but has an oxygen barrier property of 1 cm ³ / m ² · day · a.
There is a problem that it is difficult to realize a high gas barrier material (high gas barrier material) of tm or less. In addition, since the coating contains a large amount of chlorine, there is a problem in terms of waste disposal such as incineration and recycling.

[0005] Further, the above-mentioned metal vapor-deposited film on which a metal or a metal compound is vapor-deposited, a silicon oxide thin film such as silicon monoxide (SiO), and a vapor-deposited film on which a magnesium oxide (MgO) thin film is vapor-deposited are a resin film and a vapor-deposited metal. Clearly, the physical properties of the two, such as mechanical properties, chemical properties, thermal properties, etc. are very different, so the thin film of the inorganic compound used for the gas barrier layer lacks flexibility and is weak against rubbing and bending In addition, due to poor adhesion to the base material, care must be taken in handling, and there is a problem that cracks are generated and the gas barrier properties are remarkably deteriorated, especially during post-processing of packaging materials such as printing, laminating and bag making. In addition, since the device is formed by using a vacuum process such as a vacuum deposition method, a sputtering method, or a plasma enhanced chemical vapor deposition method, the apparatus is expensive. Defects, pinholes, etc. may occur in the inorganic thin film due to decomposition, degassing, etc. of the low molecular weight part or the additive part such as plasticizer, etc., and high gas barrier properties cannot be achieved, cost There is a problem that it becomes expensive.

[0006] To solve the above problem,
As described in Japanese Patent No. 295931, a gas barrier material in which a metal alkoxide coating is formed on a substrate has been proposed. Since this gas barrier material has a certain degree of flexibility and can be manufactured by a liquid phase coating method, the cost can be reduced.

However, the above gas barrier material can be said to have improved gas barrier properties as compared with the case of a single substrate, but cannot be said to have absolute gas barrier properties.

Accordingly, the present invention provides a gas barrier laminate which is flexible, has excellent gas barrier properties against oxygen, water vapor, etc., has heat resistance, moisture resistance and water resistance, and is easy to manufacture. With the goal.

[0009]

According to the first aspect of the present invention,
On a substrate made of a polymer resin composition, a coating agent mainly containing a mixed solution of one or more metal alkoxides or a hydrolyzate thereof and an isocyanate compound having at least two or more isocyanate groups in a molecule. A gas barrier laminate having a coating layer formed by applying and drying by heating, which is a first layer, and a vapor-deposited layer made of an inorganic compound, which is a second layer.

According to a second aspect of the present invention, there is provided a gas barrier laminate according to the first aspect, wherein the coating agent contains tin chloride.

A third aspect of the present invention is the gas barrier laminate according to the first aspect, wherein the coating agent contains melamine or a melamine resin.

According to a fourth aspect of the present invention, there is provided a gas barrier laminate according to the first or third aspect, wherein the coating agent contains formaldehyde.

[0013]

According to the present invention, one or more metal alkoxides or hydrolysates thereof and an isocyanate compound having at least two or more isocyanate groups in a molecule are formed on a substrate made of a polymer resin composition. The first layer is formed on the second layer by applying a coating agent containing the mixed solution as a main component and laminating the coating layer formed by heating and drying as the first layer and the vapor-deposited layer made of an inorganic compound as the second layer. It suppresses generation of defects such as pinholes, cracks, and grain boundaries or micropores. Alternatively, a dense structure formed by a reaction product between the coating agent component of the first layer and the deposited metal of the second layer has high gas barrier properties, water resistance, moisture resistance, and flexibility that can withstand a certain degree of deformation due to formation. It prevents deterioration of gas barrier properties due to cracks generated during post-processing such as printing, laminating, slitting, and bag making. Further, the first coating layer suppresses thermal damage to the base material due to the step of forming the second vapor deposition layer. Further, the coating layer exhibits high adhesion to the base material and the deposited film, and serves as an intermediate layer between the two to provide a gas barrier laminate having excellent adhesion.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail. FIG. 1 is a schematic diagram illustrating the configuration of the gas barrier laminate of the present invention.

In FIG. 1, reference numeral 1 denotes a gas barrier laminate, which is a substrate 2, a coating layer 3 as a first layer, and an inorganic vapor deposition layer 4 as a second layer. The base material 2 is in the form of a sheet or a film, and is composed of polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (Neylon-6, nylon-66, etc.). , Polyvinyl chloride, polyimide, or a copolymer of these polymers, such as those commonly used as packaging materials can be used. The base material is appropriately selected from the above materials depending on the application.

The polymer resin material used for the substrate 2 includes, for example, an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant,
Known additives such as a coloring agent can be added, and are appropriately added as needed.

Further, the surface of the substrate 2 may be subjected to surface modification such as corona treatment and anchor coating treatment to improve the adhesion of the coating.

The coating layer 4, which is the first layer, is mainly composed of a mixed solution of one or more metal alkoxides or hydrolysates thereof and an isocyanate compound having at least two isocyanate groups in the molecule. Is coated on the inorganic thin film layer 3 on the substrate 2 and dried by heating. Each component contained in the coating agent will be described in detail below.

The metal alkoxide used for the coating agent in the present invention is tetraethoxysilane [Si (OC ₂
H ₅ ) ₄ ], triisopropoxy aluminum [Al
(O-2′-C ₃ H ₇ ) ₃ ], M (OR) _n (M: metal such as Si, Ti, Ai, Zr _, R: CH ₃ ,
It can be represented by an alkyl group such as C ₂ H ₅ ), and is also used as a solution obtained by adding water (to which hydrochloric acid or the like as a catalyst is added) in advance and hydrolyzing.

The isocyanate compound having at least two isocyanate groups (NCO groups) in the molecule includes, for example, tolylene diisocyanate (TDI), triphenylmethane triisocyanate (TTI), isophorone diisocyanate (IPDI), tetramethylxylene There are monomers such as diisocyanate (TMXDI) and their polymers and derivatives.

Further, tin chloride added to the coating agent includes stannous chloride (SnCl ₂ ) and stannic chloride (SnCl ₂ ).
₄ ) or a mixture thereof, and either an anhydride or a hydrate can be used.

Further, melamine and melamine resin are added to the coating agent. Specifically, melamine alone or methylol melamine obtained by reacting melamine and formaldehyde, adducts such as dimethylol melamine,
Further, it is a melamine resin which is a polycondensate of these.

Each of the above-mentioned components can be added to a coating agent alone or in combination of several components. Further, as long as the barrier properties of the coating agent are not impaired, known components such as dispersants, stabilizers, viscosity modifiers and coloring agents can be used. Can be added.

As a method for applying the coating agent, conventionally known means such as a dipping method, a roll coating method, a screen printing method, and a spraying method are used. The thickness of the film varies depending on the type of the coating agent, but the thickness after drying may be in the range of about 0.01 to 100 μm. When the thickness is 50 μm or more, cracks are easily generated in the film. It is desirable that the thickness be 50 μm.

The inorganic vapor-deposited layer 4, which is the second layer, is made of an oxide, nitride, or fluoride such as silicon, aluminum, titanium, zirconium, or tin, or a composite thereof.
It is formed by a vacuum process such as a vacuum deposition method, a sputtering method, and a plasma vapor deposition method (CVD method).

The thickness of the inorganic vapor-deposited layer 4 varies depending on the application and the thickness of the second layer, but is preferably in the range of several tens of degrees to 5,000 degrees, but if it is less than 50 degrees, there is a problem in the continuity of the thin film.
On the other hand, if it exceeds 3000 °, cracks are liable to occur and the flexibility is lowered.

Further, on the gas barrier laminate of the present invention, a thermoplastic resin layer which can be heat-sealed if necessary,
The printing layer can be laminated on the inorganic vapor-deposited layer or the substrate 2, and a plurality of resins can be laminated via an adhesive layer.

The gas barrier laminate of the present invention will be described with reference to specific examples.

[Example 1] A coating agent obtained by combining the following compositions and mixing them in a predetermined ratio was applied to the upper surface of a 12 μm-thick polyethylene terephthalate (hereinafter referred to as PET) base material using a bar coater. The film was dried at 120 ° C. for 1 minute in a drier to form a film having a thickness of about 0.3 μm. Was formed to obtain a gas barrier laminate.

(Components of Coating Agent) (A) Tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ :
Hereinafter, 4.5 g of hydrochloric acid (0.1 N) was added to 10.4 g, and the mixture was stirred for 30 minutes and hydrolyzed. The resulting solution was diluted with ethyl acetate to a solid content of 3 wt% (in terms of SiO ₂ ). (B) Tetrabutoxy zirconium [Zr (OC
₄ H ₉ )] in ethyl acetate with a solid content of 3 wt% (ZrO ₂ equivalent). (C) 3w of isophorone diisocyanate (IDPI)
t% ethyl acetate solution. (D) Tetramethylxylene diisocyanate (TMX
DI) 3 wt% ethyl acetate solution. (E) A 3 wt% solution of stannous chloride (anhydride) in ethyl acetate. (F) A 3 wt% solution of melamine in ethyl acetate. (G) Formalin 3wt% aqueous solution

(Composition of Coating Agent) 1 (A) / (C) Mixing ratio (wt%) 60/40 2 (A) / (D) Compounding ratio (wt%) 70/30 No. 3 (A) / (D) / (E) compounding ratio (wt%) 60/40/2 4 (A) / (D) / (F) compounding ratio (wt%) 60/40/2 Example 5 No. 5 (A) / (D) / (G) compounding ratio (wt%) 60/40/1 No. 6 (B) / (D) Mixing ratio (wt%) 60/40 Comparative Example No. 6 1 No coating compounding ratio (wt%)

The gas barrier properties of the obtained gas barrier laminate were evaluated by measuring oxygen permeability and water vapor permeability. Oxygen permeability measurement device (MOCO manufactured by Modern Control Co., Ltd.) under 25 ° C.-100% RH atmosphere
N OXTRAN 10 / 40A), and the water vapor barrier property was measured at 40 ° C.-90 RH in a water vapor permeability measuring apparatus (PERMATR manufactured by Modern Control Co., Ltd.).
Measurement was performed using AN W6), and the results are shown in Table 1.
As a comparative example, a film having only a vapor-deposited film without a coating was prepared and similarly measured and evaluated.

[0033]

[Table 1]

From these, the examples in which a coating agent was applied to a vapor-deposited film (Examples Nos. 1 to 6) show that Comparative Examples No. 1 and No. 2 both have an oxygen barrier property and a water vapor barrier property. Higher gas barrier property than that of No. 1.

[Embodiment 2] [Embodiment 2] 3, Comparative Example No. After performing a predetermined elongation tensile test using a tensile tester, a laminated film obtained by laminating an unstretched polypropylene film (CPP, 30 μm) with a polyol isocyanate-based adhesive using the coated surface of the laminated film 1 as an adhesion surface was subjected to an oxygen test. The permeability and the water vapor permeability were measured, and the flexibility was further evaluated. Table 2 shows the results.

[0036]

[Table 2]

The film (No.
In the case of 2), the film was not able to withstand deformation due to tension at a stretch of several percent, causing cracks in the film, and the gas barrier property was significantly reduced.
The gas barrier laminate of the present invention shows almost no deterioration up to about 5%, and its deterioration is small even by subsequent deformation due to tension, and it has considerable flexibility as compared with the laminated film of the vapor deposition film alone of the comparative example. Have.

Example 3 Using an OPP (biaxially oriented polypropylene) film (30 μm) as a base material, 3 was used to form a coating film in the same manner as in Example 1, and SiO, Al ₂
A vapor deposition layer having a thickness of 400 ° was formed by a vacuum vapor deposition method using an electron beam heating method with O ₃ and SnO ₂ as vapor deposition sources, and the oxygen permeability and the water vapor permeability were measured and evaluated. As a comparative example, a laminated film directly provided on a substrate without a coating film was measured and evaluated in the same manner. Table 3 shows the results.

[0039]

[Table 3]

As described above, by providing a coating film on the first layer in any of the laminates using any of the evaporation sources, a remarkable improvement in gas barrier properties was observed, and a high-level gas barrier film was obtained.

[0041]

As described above, the gas-barrier laminate of the present invention comprises one or more metal alkoxides or hydrolysates thereof and at least two metal alkoxides in a molecule on a substrate made of a polymer resin composition. A coating agent containing a mixed solution of the above isocyanate compound having an isocyanate group as a main component is applied, and a coating layer formed by heating and drying is used as a first layer,
By laminating a vapor-deposited layer made of an inorganic compound as a second layer, it has high gas barrier properties, and is excellent in flexibility, water resistance, and moisture resistance. Even when laminated with another resin, its strength is sufficient. It is practical. That is, even under a high humidity atmosphere, long-term storage is possible without impairing the gas barrier properties and without deteriorating contents such as food and medicine. Further, the present invention has an effect that gas barrier properties are not impaired even in post-processing such as printing, laminating, and bag making as a packaging material.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of a gas barrier laminate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas barrier laminated body 2 Substrate 3 Coating layer 4 Inorganic vapor deposition layer

Claims (4)

(57) [Claims] 1. A mixed solution of at least one metal alkoxide or a hydrolyzate thereof and an isocyanate compound having at least two isocyanate groups in a molecule on a substrate made of a polymer resin composition. A gas-barrier laminate comprising a coating layer formed by applying a coating agent, and drying by heating to form a first layer, and a deposition layer made of an inorganic compound as a second layer. 2. The gas barrier laminate according to claim 1, wherein the coating agent contains tin chloride. 3. The gas barrier laminate according to claim 1, wherein the coating agent contains melamine or a melamine resin. 4. The method of claim 1 or 3 gas barrier laminate according characterized in that it comprises a formaldehyde to said coating agent.