JPS595059A - High gas barriering multilayer film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high gas barrier multilayer film whose gas barrier properties are improved.

Conventionally, nylon films and their multilayer films are well known as high gas barrier films.
Under high humidity conditions, the oxygen gas barrier properties of nylon films decrease significantly due to nylon's water absorption properties, and there are limits to their use in packaging food products that are susceptible to stripes and deterioration due to oxygen gas. .

For example, in the case of a certain nylon multilayer film, 25℃・d
Oxygen gas permeability under ry conditions is approximately 30cc/n? -6 hours at 24hr-atm,
Approximately 180-200cc under conditions of 25℃ and 96%RH
This fact can be seen from the dramatic increase in the average cost of /d・24hr-atm.

The present invention relates to the improvement of a tubular multilayer film having a nylon resin layer as the outermost layer, which is particularly suitable for packaging leather goods. The point is that

The nylon resin in the present invention is nylon 6.6-6
Examples include copolymers thereof and copolymers with other compounds, and there are no particular limitations. A tubular multilayer film is, for example, a tube made by laminating, for example, a film made of polyolefin thread resin through a bonding layer, by coextrusion, in order to improve the heat sealability of the outermost film layer made of nylon resin. Examples include the following, and there should be no particular limitation. At this time, place the adhesive layer in a pot at °C.
A polymer containing a modified polyolefin having a polar group obtained by graft polymerizing a dibasic acid such as maleic anhydride or fumaric acid to a Va 3 lyolefin polymer is suitable, and other examples include ionomer resins. Examples of the polyolefin thread resin used for the innermost layer to improve the properties include polyethylene, ethylene-vinyl acetate copolymer, etc., but these are not limited and may be used as appropriate.

The above is just an example of the configuration of the multi-layer film, and the present invention can also take other appropriate configurations.

The polyvinylidene chloride resin may be a common resin, and most exist in the form of a copolymer of vinylidene chloride and another compound, but in the present invention, an emulsion of polyvinylidene chloride is particularly preferred. This polyvinylidene chloride emulsion has adhesive properties with the nylon thread film and can be laminated directly, which is convenient because an anchor coat is not required.

Therefore, in the case of anchor coating as in the past, two steps of coating treatment and drying are required, but in the present invention, these steps are completely unnecessary and lead to a single line of the process. In order to form a polyvinylidene chloride thread resin layer, for example, a multilayer film having a nylon resin layer as the outermost layer is passed through a polyvinylidene chloride emulsion bath, a Meyer bar is applied to both sides to make the thickness uniform, and the film is passed through a drying oven. Drying may be sufficient, but other appropriate methods may also be used. At this time, a method of coating a stretched nylon flat film with polyvinylidene chloride emulsion may be considered, but in this case, it is applied to one side of the film using a coater, etc., but if a coater wider than the inside of the film is used, the back side of the film may be stained. Due to the drawbacks of coating, it is necessary to coat with a coater that is narrower than the inside of the film, so the edges cannot be coated, so that part can be cut and used, or the sealant can be used by pasting Kawa's polyolefin thread film in the post process. He was offering it. However, when coating the tubular multilayer film of the present invention with a polyvinylidene chloride emulsion, the edges can also be cut using sealant.
It also has the advantage that lamination of commercial films can be easily and extremely advantageously produced.

The film according to the present invention can be used for packaging meat and processed products, packaging processed seafood products, packaging miso, ketchup, mayonnaise, edible oil, etc., packaging pickles, and other appropriate packaging. It is also applied to the packaging of machines, instruments, parts, etc. Particularly limited: 1. It's not something you can do.

The present invention is as described above, and according to the present invention, the gas barrier properties are significantly improved even under high humidity conditions, and a great effect is expected for various packaging, especially for fresh food packaging. This has particularly remarkable effects, such as greatly increasing the number of storage days and reducing troubles during the distribution process. <Example 1> The outermost layer is made of nylon with a thickness of 25 μm, and the middle layer is made of nylon with a thickness of 6. It is a modified polyethylene having polar groups made by graft copolymerizing maleic anhydride to polyethylene, and the inner layer is low-density polyethylene.A tubular multilayer film with a thickness of 80μ is passed through a hard and 48% vinylidene chloride emulsion bath. ,
Apply the Mayer bar from both sides to a thickness of 3 μm,
A high gas barrier multilayer film was prepared by drying it in a drying oven and was subjected to the tests shown in Table 1.

Comparative Example 1 A tubular multilayer film prepared by the method of Example +11 was subjected to the tests shown in Table 1.

The results of these tests are listed below.

7. As mentioned above, the multilayer film according to the present invention has high gas barrier properties and can be widely applied to various packaging including fresh foods. It is something that can be done.

patent applicant Gunze Co., Ltd. Representative Ishi 1) Tadashi

Claims (1)

[Claims] A high gas barrier multilayer film made of a tubular multilayer film whose outermost layer is a nylon resin layer, and a polyvinylidene chloride resin layer.