JP2001205761A - Laminate having excellent pinhole resistance and packaging bag using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent packaging laminate having no environmental problem regarding a waste, excellent bending pinhole resistance during transportation or the like and no blocking at a production time in the laminate made of a stretched nylon film and a sealant film and a packaging bag using the laminate. SOLUTION: In the laminate, at least its outermost layer is made of the stretched nylon film 10b having an inorganic oxide vapor-deposited layer, and its innermost layer is made of the sealant film 40. A surface coating agent layer 30 is provided on an outer surface of the nylon film. The coating agent is obtained by adding a single polyethylene wax or a mixture of a polyethylene wax and a fatty acid amide to either a medium containing a polyamide resin and a nitrocellulose or a medium containing a urethane resin and a vinyl chloride/vinyl acetate copolymer resin. Thus, the laminate 1 having excellent pinhole resistance is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate for packaging based on a biaxially stretched polyamide (nylon) film having excellent flexibility, and more particularly to bending and friction during transportation or the like. The present invention relates to a packaging bag for storing foods and medicines using a laminate excellent in pinhole resistance due to the above.

[0002]

2. Description of the Related Art Conventionally, a transparent barrier wrapping material using a flexible biaxially stretched polyamide (nylon) film having a barrier property as a barrier substrate is excellent in pinhole resistance due to bending and friction during transportation or the like. Therefore, it is widely used as a barrier packaging bag for storing foods, pharmaceuticals and the like.

As the above-mentioned barrier packaging material having pinhole resistance, for example, a sealant film in which the outermost layer is a stretched nylon film coated with polyvinyl chloride resin and the innermost layer is a linear low-density polyethylene resin is dry-laminated. Some were laminated via an adhesive for use.

However, in the packaging material having the above-mentioned structure, polyvinyldene chloride used in the barrier layer is repelled by environmental problems relating to wastes, such as generation of harmful gases such as chlorine gas and dioxin in incineration treatment after use. It became so. As an alternative to this polyvinyl chloride, aluminum foil was laminated on a stretched nylon film, but in some cases it was not transparent.However, incineration of waste caused the aluminum ingot to damage the incinerator or the incineration ash. However, as with polyvinyl chloride, there are environmental issues related to waste, such as the generation of harmful gases at landfill sites, and this has also been avoided.

[0005] In recent years, instead of these gas barrier layers, inorganic oxides such as silicon oxide and aluminum oxide deposited on a stretched nylon film have been widely used as transparent gas barrier films. As an example of a packaging material using the same, there was a laminated film obtained by laminating a vapor-deposited surface of a stretched nylon film on which silicon oxide was vapor-deposited and a sealant film made of a linear low-density polyethylene resin via a dry lamination adhesive. .

However, in the packaging bag using the laminated film having the above-described structure, the stretched nylon film on which silicon oxide is deposited is harder than the conventional stretched nylon film coated with vinylidene chloride. Pinholes are likely to be generated due to friction or the like, resulting in a lack of barrier properties. For example, in the case of packaging bags made of raw bread crumbs, sliced cheese or the like, there is a problem that molds are generated in the contents.

In order to solve such a problem, a soft surface coating agent such as polyamide OP varnish is applied on the outer surface of a stretched nylon film of the above-described packaging laminated film on which a metal oxide such as silicon oxide is deposited. As a result of testing the pinhole resistance due to bending of the packaging bag using the laminated film,
Although the occurrence of pinholes has been eliminated, there has been a problem in producing this web-shaped laminated film that blocking occurs when the laminated film is wound up.

[0008] Further, as a packaging body which is likely to generate pinholes during transportation or the like and does not require gas barrier properties but requires bending pinhole resistance, there is a packaging bag for accommodating, for example, a liquid soup. As the packaging material, for example, there was a material obtained by laminating a flexible stretched nylon film and a linear low-density polyethylene film with an adhesive for dry lamination, but also inferior in bending pinhole resistance,
There is a problem that a liquid leak or the like occurs.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and an object thereof is to provide a flexible biaxially stretched polyamide film provided with an inorganic oxide vapor-deposited layer. An outer layer, a transparent laminated film with a sealant film as the innermost layer in the innermost layer, without environmental problems related to waste, no pinholes due to bending and friction during transportation, etc., and at the time of production An object of the present invention is to provide a transparent packaging laminate having no blocking in winding and a packaging bag using the same.

[0010]

Means for Solving the Problems In order to achieve the above object in the present invention, first, in the invention of claim 1, at least the outermost layer is a biaxially stretched polyamide film provided with an inorganic oxide deposition layer. A laminate having excellent pinhole resistance, characterized in that a surface coating agent is applied to the outer surface of the biaxially stretched polyamide film in the laminate having an inner layer made of a sealant film.

In the invention of claim 2, the surface coating agent comprises a polyamide resin, a medium or urethane resin containing nitrocellulose, and a vinyl chloride-vinyl acetate copolymer resin (hereinafter, referred to as a vinyl chloride-vinyl acetate copolymer resin). 2. A laminate having excellent pinhole resistance according to claim 1, wherein a single substance of polyethylene wax or a mixture of polyethylene wax and fatty acid amide is added to one of the media.

According to the first or second aspect of the present invention, by providing a soft surface coating agent on the outer surface of the biaxially stretched polyamide film as the outermost layer, a laminate for packaging excellent in bending resistance and friction pinhole resistance is provided. The surface coating agent may be a coating liquid in which an additive such as polyethylene wax is added to either a medium containing polyamide resin and nitrocellulose or a medium containing urethane and vinyl chloride-vinyl acetate copolymer resin. Accordingly, a laminate having no blocking in winding the web-like laminate at the time of production can be obtained.

According to the third aspect of the present invention, in the first aspect,
Or a packaging bag using the laminate having excellent pinhole resistance described in 2.

According to the third aspect of the present invention, since the laminated body having excellent pinhole resistance is used, there is no fear that the barrier property is lacked or liquid leaks due to bending or friction during transportation or the like. It can be a transparent packaging bag.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing an embodiment of the laminate excellent in pinhole resistance of the present invention in a side cross section, and FIG. 2 is a diagram showing another embodiment of the laminate excellent in pinhole resistance of the present invention. FIG. 2 is an explanatory diagram showing one embodiment in a side cross section.

First, as shown in the side sectional view of FIG. 1, for example, a stretched nylon film (10b) having a vapor-deposited layer (10a) of an inorganic oxide as an outermost layer, as shown in the side sectional view of FIG. ) As a barrier film (10), and a laminate (1) for packaging obtained by laminating a sealant film (40) as an innermost layer via a vapor deposition layer (10a) surface and an adhesive layer (20). The surface coating agent layer (30) is provided on the outer surface of the stretched nylon film (10b).

As the barrier film (10), for example, a stretched nylon film (10
b) An anchor coat layer (not shown) is applied between the vapor deposition layer (10a) and a coating layer (not shown) is further applied on the vapor deposition layer (10a) to rub the vapor deposition layer (10a). Film (2) to prevent cracks
0).

As the anchor coat layer, for example, at least an acrylic polyol, an isocyanate compound, and a compound represented by the general formula: R'SI (OR) ₃ (where R 'is an alkyl group, a vinyl group, or a glycyoxypropyl group, and R is an alkyl group) Or a composition containing a trifunctional organosilane or a hydrolyzate of an organosilane represented by the following formula: or a general formula: M (OR) _n (where M is a metal element, R is CH ₃ , C ₂₎ An alkyl group such as H ₅ , and n is a metal alkoxide represented by the oxidation number of the metal element) or a composition containing a hydrolyzate of the metal alkoxide can be used.

The coating layer may be, for example, an aqueous solution containing at least one of a water-soluble polymer and (a) at least one metal alkoxide and its hydrolyzate, and (b) tin chloride, or a water / alcohol mixture. Can be used.

The above-mentioned laminate for packaging requiring gas barrier properties is suitably used as a transparent packaging bag having a resistance to bending and a resistance to pinholes for accommodating, for example, raw bread crumbs, rice cakes, sliced cheese and the like. Can be

As shown in the side sectional view of FIG. 2, for example, a stretched nylon film (10b) is formed as the outermost layer, and the back surface of the stretched nylon film (10b) and the adhesive layer (2b).
0), the sealant film (4) as the innermost layer
0), wherein a surface coating agent layer (30) is provided on the outer surface of the stretched nylon film (10b).

The packaging laminate having the above-described structure that does not require gas barrier properties is suitably used as a transparent packaging bag having, for example, a bending resistance and a friction pinhole resistance for accommodating a liquid soup or the like.

The biaxially stretched polyamide (nylon) film (10b) used as the outermost layer constituting the laminate having excellent pinhole resistance of the present invention is preferably a film having a thickness of about 15 μm. ONP (trade name, manufactured by Unitika) and N2102 (trade name, manufactured by Toyobo Co., Ltd.) to which a softener is added can be more preferably used.
In addition to these stretched nylon films, for example, a co-pressed barrier nylon film, a barrier coating film (a film coated with a barrier layer), or another nylon film may be used.

The inorganic oxide deposited layer (10a) constituting the barrier film (10) may be SiO ₂ , S
The transparent barrier film (10) can be obtained by a physical vapor deposition method or a chemical vapor deposition method using iO, Al ₂ O ₃ or the like as a deposition material.

The surface coating agent layer (30) constituting the laminate (1) having excellent pinhole resistance according to the present invention is, for example, a polyamide resin dissolved in nitrocellulose medium, and polyethylene as an additive. A coating solution obtained by adding about 3% by weight of a simple substance of wax or a mixture of polyethylene wax and fatty acid amide to a thickness of about 5 μm by gravure coating or the like on the entire surface (the entire surface has a uniform thickness) or by applying a partial coating on necessary portions. Can be

A coating solution in which the same additives as described above are added to a blend resin of a urethane resin and a vinyl chloride-vinyl acetate copolymer resin may be used.

Further, the innermost sealant film (4) constituting the laminate (1) having excellent pinhole resistance of the present invention.
As 0), a linear low-density polyethylene film, a low-density polyethylene film, a high-density polyethylene film or an unstretched polypropylene film is used,
Among them, the linear low-density polyethylene film can be suitably used for improving the bending pinhole resistance from the viewpoint of softening the laminate (1).

[0028]

Next, the present invention will be described in detail with reference to examples.

Example 1 As shown in the side sectional view of FIG. 1, as an outermost barrier film (10), an anchor coat layer (not shown) having a thickness of about 0.1 μm and having the following composition was formed on the surface. the provided, deposition layer made of Al ₂ 0 ₃ (10a) is formed by vacuum deposition thereon, further (not shown) covering layer having the following composition thereon is provided, further anchor coating agent: product AD980A / AD98
15B stretched nylon film (10b) coated with OB (manufactured by Toyo Morton Co., Ltd.): A pattern or explanatory text is printed on the anchor coat agent side of trade name ON (manufactured by Unitika) to obtain a laminate. Outside substrate.

Components of the anchor coat layer: In a diluent solvent, 2- (epoxycyclohexane) ethyltrimethylsilane (hereinafter referred to as EETMS) was mixed with 2.5 times (weight ratio) of acrylic polyol, and tin chloride was further added. / Methanol solution (adjusted to 0.003 mol / g) with EETM
S was added so as to be 1.135 mol with respect to S, and then tolylene diisocyanate was mixed so that the NCO group was equivalent to the OH group of the acrylic polyol. Ingredients of the coating layer: To 10.4 g of tetraethoxysilane, 89.6 g of hydrochloric acid (0.1N) was added, and the mixture was stirred for 30 minutes.
A solution having a hydrolyzed solid content of 3 wt% (in terms of SiO ₂ ) and a polyvinyl alcohol solution were mixed.

Subsequently, a coating solution having the following composition was applied to the entire outer surface of the stretched nylon film (10b) constituting the outer substrate of the laminate obtained above by a gravure coating method so as to have a thickness of 5 μm. An agent layer (30) was formed.

Liquid composition of the above-mentioned surface coating agent layer (30): 70 parts of polyamide resin and 30 parts of nitrocellulose in a medium, polyethylene wax and fatty acid amide Additive: trade name Additive # 150 (manufactured by Toyo Ink Mfg. Co., Ltd.) ) Was added as a coating liquid by adding 3% by weight.

Subsequently, an adhesive for dry lamination is applied to the anchor coating agent surface of the barrier film (10) constituting the outer substrate coated with the surface coating agent layer (30) as described above:
A969V / A5 (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.) as an adhesive layer (20), and a linear low-density polyethylene film having a thickness of 40 μm as a sealant film (40): TUX-TCS (trade name: 0.915, East Sello Was laminated to obtain a laminate (1) having excellent pinhole resistance.

Example 2 A liquid composition of a surface coating agent for forming a surface coating agent layer (30) was added to a blend resin of a urethane resin and a vinyl chloride-vinyl acetate copolymer resin comprising a polyethylene wax and a fatty acid amide. Agent: A laminate (1) having excellent pinhole resistance was obtained in the same manner as in Example 1, except that 3% by weight of an additive # 150 (manufactured by Toyo Ink Mfg. Co., Ltd.) was added as a coating solution. Was.

Example 3 The composition of the pinhole-resistant coating agent for forming the surface coating agent layer (30) was changed to a blend resin of a urethane resin and a vinyl chloride-vinyl acetate copolymer, a polyethylene wax and a fatty acid amide. Additive consisting of: trade name additive # 150 (manufactured by Toyo Ink Manufacturing Co., Ltd.) (2
Liquid type) was added in the same manner as in Example 1 except that 3% by weight was added to obtain a coating liquid, thereby obtaining a laminate (1) having excellent pinhole resistance.

<Comparative Example 1> The liquid composition of the surface coating agent for forming the surface coating agent layer (30) was a coating liquid composed of a two-part type urethane resin: trade name X331 cassette OP varnish (manufactured by Toyo Ink Mfg. Co., Ltd.). A laminate was obtained in the same manner as in Example 1 except that the above procedure was repeated.

Comparative Example 2 A laminate was obtained in the same manner as in Example 1 except that the surface coating agent layer (30) shown in FIG. 1 was omitted.

Each of the laminates obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was folded in four to form a test sample having sharpened corners.
mm, amplitude speed: 20 times / min, load: 50 g, friction object: inner surface of cardboard, number of times of friction: 50 to 200 times, n number:
Under the condition of 3, a friction test was performed on the corner portions of the laminated structure, and the results are shown in Table 1 as x when there was a pinhole and ○ when there was no pinhole.

Further, as a test for blocking resistance, a total of 1 kg / liter of the sealant film surface and the surface coating agent layer (30) surface (the sealant film surface and the stretched nylon film outer surface in Comparative Example 2) of the obtained laminate was tested. 2 times each under the conditions of cm ² and 10 kg / cm ² ,
Was evaluated by a five-step method in which 1 was evaluated as good and 1 was evaluated as poor. The results are shown in Table 2.

[0040]

[Table 1]

[0041]

[Table 2]

From Table 1, any surface coating agent layer (30)
Is also excellent in the flex pinhole resistance, whereas the laminate excluding the surface coating agent layer (30) as in the laminate of Comparative Example 2 is inferior in the flex pinhole resistance. Was something. Also, from Table 2, the surface coating agent was prepared by adding an additive such as polyethylene wax to either a medium containing a polyamide resin and nitrocellulose or a medium containing a urethane resin and a bihydrochloride copolymer resin. It had excellent blocking properties.

[0043]

As described above, the present invention has the following effects. That is, at least the outermost layer is a biaxially stretched polyamide film having an inorganic oxide vapor-deposited layer, and in a packaging laminate in which the innermost layer is a sealant film, a soft surface coating agent layer is provided on the outer surface of the biaxially stretched polyamide film. Therefore, a laminate for packaging having excellent bending resistance and pinhole resistance during transportation or the like can be obtained.

Further, the surface coating agent may be prepared as a coating liquid in which an additive such as polyethylene wax is added to either a medium containing polyamide resin and nitrocellulose or a medium containing urethane and vinyl chloride-vinyl acetate copolymer resin. When the web-like laminate is wound, a laminate having no blocking can be obtained.

Accordingly, the present invention has an excellent practical effect as a transparent packaging bag which accommodates foods and medicines which require gas barrier properties, and has excellent bending resistance and friction pinhole resistance during transportation. Demonstrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a laminate having excellent pinhole resistance according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the laminate having excellent pinhole resistance according to the present invention.

[Explanation of symbols]

 1) Laminate having excellent pinhole resistance 10) Barrier film 10a {Vapor deposition layer 10a} Stretched nylon film 20} Adhesive layer 30} Surface coating agent layer 40} Sealant film

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C09D 123/06 C09D 127/08 127/08 131/04 B 131/04 175/04 175/04 177/00 177/00 A61J 1/00 331C F-term (reference) 3E086 AD01 BA04 BA15 BA24 BA33 BA40 BB51 BB90 CA01 CA28 4F100 AA01A AA17A AA19 AH02D AH03D AJ06D AK04D AK15D AK22D AK46B AK46B14E17 BAK18B14A01 JL00 JL12C JN01 4J038 BA081 BA082 CB021 CB022 CD061 CD062 CF041 CF042 DG001 DG002 DH001 DH002 JB12 NA10 NA11 PB04 PC08

Claims (3)

[Claims] 1. A laminate comprising at least an outermost layer of a biaxially stretched polyamide film having an inorganic oxide vapor-deposited layer and an innermost layer of a sealant film, wherein a surface coating agent is applied to the outer surface of the biaxially stretched polyamide film. A laminate having excellent pinhole resistance. 2. A method according to claim 1, wherein the surface coating agent is a medium containing a polyamide resin and nitrocellulose, or a medium containing a urethane resin and a vinyl chloride-vinyl acetate copolymer. 2. The laminate having excellent pinhole resistance according to claim 1, wherein a mixture is added. 3. A packaging bag using the laminate having excellent pinhole resistance according to claim 1 or 2.