JPH03289401A - Zipper and packing bag - Google Patents

Abstract

PURPOSE:To restrict transmission of volatile or unvolatile component contained in goods through a packing material during storage and distribution by making a zipper of ethylene-vinyl alcohol copolymer resin(EVOH). CONSTITUTION:A zipper made of EVOH is prominent in airtightness due to its appropriate degree of humidity absorption when a protruding part and a recessed part engages with each other. Accordingly, a packing bag using this zipper permits little flavor component or the like contained in a content to leak out of a zipper part. The zipper is employed at an opening of the packing bag made of an arbitrary material, and especially when it is employed at the opening of the packing bag the innermost layer of which is made of an EVOH layer, it is remarkably effective, for example, for reducing absorption of flavor component. The EVOH used here is 20 to 60mol% preferably 25 to 50mol%, in the ethylene content, and 90mol% or more, preferably 95mol% or more, in the saponification of vinyl acetate component. The zipper and the innermost layer of the packing bag may be employed the same or a different EVOH, but it is most preferable that the EVOH for the innermost layer has a heat sealing property.

Description

[Detailed Description of the Invention] A. Part 11-1 In cases where trace amounts of volatile or non-volatile components contained in ingredients, whether food or non-food (e.g. pharmaceuticals), affect the commercial value of the product. are recognized in many cases. Examples include flavor components in foods and medicinal components in pharmaceuticals.

The packaging of these products plays an important role in maintaining the product quality designed by the manufacturer, but in reality, before it is delivered to the consumer, there are many problems such as dissipation through the packaging material, adsorption to the packaging material, and after opening. The reality is that there are many cases in which the design quality is significantly impaired due to a significant decrease due to the emission of The zipper and the packaging bag using the same according to the present invention improve the drawbacks of these conventional packaging bags, thereby preventing deterioration of product value and helping to maintain product quality.

Conventionally, materials such as polyethylene and polypropylene have been used for zipper closures, but the airtightness between the protrusions and recesses of the zipper is not sufficient. Therefore, there is a risk that the flavor components of the contents packed in a packaging bag obtained using such a zipper may leak. In addition, even if packaging bags using conventional technology incorporate materials that have a barrier effect against volatile components such as flavor components and medicinal components, or non-volatile components, the resin used for the innermost layer is typically polyethylene or polypropylene. Since the polyolefin is a polyolefin or a mixture mainly composed of the polyolefin, adsorption of the above-mentioned components to the heat sealing material of the innermost layer is unavoidable, making it difficult to maintain sufficient quality.

The present invention aims to provide a packaging bag that is effective in maintaining product value by solving the following three problems.

In other words, ■ suppressing the permeation of volatile or non-sulfur-emitting components contained in the product mainly through the packaging material during the storage and distribution stage, ■ suppressing adsorption to the packaging material, and ■ reducing the amount due to dissipation after opening at the consumer's hands. Preventing target decline.

(), i! I! The inventors of the present invention have conducted various studies to solve these problems and create a packaging bag that is effective in maintaining product value, and have developed a packaging bag made of ethylene-vinyl alcohol copolymer resin (EVOH). Zipper 1 Furthermore, by using EVOH in the innermost layer and incorporating a zipper made of EVOH into the opening, a packaging bag has a function of maintaining product value that is much superior to that of conventionally used packaging bags. This is what led us to obtain this.

The zipper made of EVOH of the present invention (the interlocking part consisting of a tape-like material having a convex part that can be opened and closed and a tape-like part having a concave part) has a convex shape because EVOH has moderate hygroscopicity. The airtightness due to the interlocking of the recessed part and the recessed part is excellent, and therefore, packaging bags obtained using such a zipper have extremely little leakage of the flavor components of the contents from the zipper part. The zipper of the present invention can be used at the opening of a packaging bag made of any material, but is particularly effective when used at the opening of a packaging bag whose innermost layer is an EVOH layer.

By separately melt-extruding a zipper made of EVOH from a die onto the innermost EVOH layer, the integral molding is completed and no separation occurs between the innermost layer and the occlusal part. In addition, a separately prepared zipper made of EVOH is attached to the innermost EVOH layer using an EVOH adhesive (for example,
By using an organic solvent solution in which a metal chloride such as magnesium is dissolved as described in No. 1154, peeling does not occur even when laminated.

In this way, by using EVOH for both the innermost layer and the occlusal part, it is possible to strongly laminate the two in a simple manner, and by providing the EVOH layer in the innermost layer, adsorption of flavor components can be reduced. You can.

In the present invention, EVOH is a saponified ethylene-vinyl acetate copolymer, with an ethylene content of 20 to 60 mol%, preferably 25 to 50 mol%, and a degree of saponification of the vinyl acetate component of 90 mol% or more, preferably 95 mol% or more can be used. If the ethylene content is less than 20 mol%, the melt moldability will be poor, while if it exceeds 60 mol%, the gas barrier properties will be insufficient and the amount of flavor components adsorbed will also increase, which is not suitable. In addition, when the degree of saponification is less than 90 mol%,
Gas barrier properties and thermal stability deteriorate, and the amount of flavor components adsorbed increases, making it unsuitable. Also, the E
VOH may contain other monomers such as propylene, butylene, unsaturated carboxylic acids or their esters ((meth)acrylic acid, (meth)acrylic esters (methyl, It is also possible to copolymerize vinylsilane compounds (vinyltrimethoxysilane, vinyltriethoxysilane, etc.), vinylpyrrolidone (N-vinylpyrrolidone, etc.)]. Furthermore, EVOH has a suitable melt index (MI: 19
0°C, under 2160g load> is O.

1-50 g/10 min, optimally 0,5-20 g/10
It's a minute. Further, as the EVOH, the above-mentioned EVOH may be used alone, or two or more types of EVOH may be used in combination. Furthermore, other resins such as ethylene-vinyl acetate copolymer or partially saponified products thereof, maleic anhydride or methacrylic acid modified polyolefins, additives (
Fillers, plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, colorants, etc.) can also be blended.

EVOH used for the zipper and EVO used for the innermost layer
H may be the same EVOH, or a different E
VOH is also fine.

As the EVOH used for the innermost layer, it is particularly preferable to use heat-sealable EVOH from the viewpoint of bag manufacturing, and examples thereof include the following. EVOH with an ethylene content of 40 to 60 mol% and/or MIo, 5 to 20 g/min, EVOHl copolymerized and modified with a vinylsilane compound (vinyltrimethoxysilane, vinyltriethoxysilane, etc.)
Alternatively, as described in JP-A-1-279949, EVOH is blended with 5 to 40% by weight of a saponified ethylene-vinyl acetate copolymer having an ethylene content of 80 to 94 mol% and a saponification degree of vinyl acetate component of 20 mol% or more. Examples include EVOH mixed with 5 to 40% by weight of ethylene-vinyl acetate copolymer having an ethylene content of 80 to 94 mol%. The packaging bag obtained in this way is
It is useful for food packaging, cosmetic packaging, and pharmaceutical packaging. The present invention will be further explained below with reference to Examples.

Example 1 The ethylene content was 47 mol%, the degree of saponification was 99 mol%, and the copolymer unit was 0 vinyltrimethoxysilane as the third component.
．． EVO containing 5 mol% and having an Ml of 565 g/10 min
A 30 μm thick (biaxially stretched or unstretched) film made of H is dry laminated with a 15 μm thick biaxially stretched nylon film using a polyurethane adhesive.
○A resin composition consisting of 80 parts of H and 20 parts of a partially saponified ethylene-vinyl acetate copolymer resin with an ethylene content of 89 mol% and a saponification degree of vinyl acetate component of 71 mol% was diced into separate dies having a convex cross section and a concave cross section. A zipper having a convex part and a concave part is formed by melt-extruding it into a tape shape, and then heat-sealing the innermost layers so that the EVOH film surface becomes the innermost layer to make a bag.
A bag with a 0 cm occlusal part was created. Next, 2 g of d-limonene as a flavor component was sealed in this bag, the interlocking part was closed, and the bag was placed in a sealed glass container and stored in an atmosphere of 20° C. and 65% RH. As an index to evaluate its usefulness,
The time it took for the odor to leak from the packaging bag was measured by a sensory test after opening the cap of the glass container. Furthermore, after 30 days of storage, the bag was disassembled and the amount of d-limonene adsorbed to the innermost layer was measured using a gas chromatograph. The results are shown in Table-1.

Comparative Example 1 A 50 μm thick low density polyethylene film and a 15 μm thick biaxially oriented nylon film were dry laminated using a polyurethane adhesive, and the low density polyethylene surface of the laminate film was coated with a convex cross section of low density polyethylene. The tape is extruded from a separate die with a concave cross section and integrated to form a zipper with a convex part and a concave part, and the innermost layers are heated together so that the low density polyethylene film surface is the innermost layer. Seal it and make a bag the same size as in Example 1. The usefulness of the obtained bag was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Table 1 The zipper made of EVOH of the present invention has high airtightness, and the packaging bag in which this zipper is provided at the opening of the packaging bag whose innermost layer is an EVOH layer is more commonly used than before. Compared to the packaging bags used for packaging bags, the permeation of flavor components is small, the amount of adsorption to the packaging bags is small, and the quantitative decrease in flavor components is small.

Claims (3)

[Claims] (1) Zipper made of ethylene-vinyl alcohol copolymer resin. (2) A packaging bag having an ethylene-vinyl alcohol copolymer resin layer as the innermost layer and a zipper made of ethylene-vinyl alcohol copolymer resin at the opening. (3) The packaging bag according to claim 2, wherein the innermost layer is a heat-sealable ethylene-vinyl alcohol copolymer resin layer.