JPS5882747A - Packing material, gas permeability thereof is adjusted - 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 packaging material with controlled air permeability and good mechanical strength.

Recently, due to advances in packaging forms, plastic films used as packaging materials are required to have extremely high gas permeability, especially oxygen permeability, and conversely, low gas permeability. Reducing gas permeability is
By coating the surface of the film with polyvinylidene chloride, a satisfactory solution has been reached. However, increasing gas permeability is not easy, and currently the only way to increase gas permeability is by selecting a film.
There is a limit to its growth. When extremely high gas permeability is required, pores are currently formed in a plastic film to produce a porous plastic film. However, in this case, liquids as well as gases must be allowed to pass therethrough, and the material cannot be used as a packaging material that is required to block liquids.

In particular, a powder oxygen absorber based on hydrosulfide has been developed in recent years, but the gas permeability of the packaging film containing this oxygen absorber must be adjusted depending on the use of the oxygen absorber. There is a need to. In other words, this oxygen absorber is a bag-like body made of paper or plastic film containing powder that has so-called oxygen scavenging ability, which absorbs and fixes oxygen from the air. This is controlled by adjusting the amount of gas permeation (gas permeation amount) in the packaging film, but if the packaging material is paper, the oxygen removal rate is too high, and if the packaging material is plastic film, the oxygen removal rate is too low. This problem arises, and it becomes important how to obtain an intermediate deoxidation rate.

As a result of extensive research to solve these problems, the present inventors created a breathable heat-sealing film by punching a large number of pores in the heat-sealable film surface, and created a heat-sealable film. A packaging film with controlled air permeability is formed by punching pores of a size and number according to the desired air permeability on the surface of a heat-resistant film with a higher melting point than the sealing film, and then bonding both films together with an adhesive. It was discovered that by laminating layers, air permeability can be adjusted, and a packaging material having good watertightness and mechanical strength can be obtained, and the present invention has been completed.

In the packaging material of the present invention, the type of packaging film forming the outer surface is selected in relation to the heat-sealing film, and a heat-resistant film with a high melting point is used. Examples of this packaging film include polyolefins such as polyethylene, polyzolopyrene, and polybutadiene, polyesters such as polyethylene terephthalate, polyamides such as nylon 6, nylon 6.6, etc.
In addition to various plastic films such as polyvinyl compounds such as polyvinyl chloride and polystyrene, cellophane and the like are also applicable. Of course, as the plastic film in the present invention, in addition to the above-mentioned polymers, the present invention can be applied to films of copolymers thereof, Blen P, etc., and also to laminate films thereof. The thickness of this film is not particularly limited, but is usually 10 microns or more, preferably 20 to 100 microns.

In the present invention, pores are formed in this film, and the pores in this case have a diameter of 0.1 tm to 3 mm.

Preferably it is about 0.5 m to IW. The number of pores to be formed is selected depending on the desired air permeability, but is generally 2 to 50, preferably 2 to 20 per toti.

The film forming the heat-sealing surface of the packaging material of the present invention has a lower melting point than the packaging film described above.

The reason for this is that when the packaging materials of the present invention are heat-sealed to each other or to other films, only the sealing surfaces are melt-bonded. Of course, no special measures are required when bonding is performed without heat sealing.

As this heat-sealing film, the various plastic films described above are applicable, but the type actually used is selected in relation to the packaging film forming the outer surface, as described above. Packaging film used in the present invention/
Preferred combinations of films for heat sealing include nylon/polyethylene, polyester/polyethylene, nylon/polypropylene/, polyester/polypropylene, cellophane/4') ethylene, cellophane/4sl robylene, polyzolopylene/polyethylene, polyzolopylene/
, IP polyvinyl chloride, etc. Of course, even if the materials are similar, materials with different degrees of crystallinity will have different melting points, so they can be used in similar combinations by utilizing the difference in melting points.

The thickness of the film forming the heat sealing surface is not particularly limited, but is usually 10μ or more, preferably 20 to 100μ.
It is. Further, it is preferable that the pores formed therein be as small as possible and as many as possible uniformly. In general, the size thereof is 1 to 21 m/K, preferably about 0.3 to 1 earthquake, and the number thereof is 25 to 100, preferably 40 to 70 per 1 d. In any case, the pores are perforated in this heat-sealing film and the air permeability thereof is selected so that it can be freely ventilated, similar to the case of kraft paper (8051-/m').

The packaging material of the present invention has a structure in which the two types of films described above are bonded and laminated using an adhesive. In this case, the adhesive used is one commonly used for this type of plastic film, such as a solution or emulsion containing a thermoplastic resin such as polyethylene, polypropylene, polyacrylate, polyvinyl acetate, or polytolylene diincyanate. . Moreover, dry lamination adhesion is preferable as the adhesion method. Generally, the amount of adhesive is 1 piece of film ~20i9'-1 usually 5~15? It is.

The packaging material according to the present invention differs from conventional packaging materials in that its air permeability is arbitrarily adjusted according to the size and size of the pores on the outer surface, and air permeability adjustment is required. It is suitable for packaging materials, such as packaging for oxygen absorbers and desiccant materials, and packaging for foods that breathe, such as fruits and vegetables. Moreover, unlike paper, this packaging material has a water-resistant outer surface and is watertight overall, so it will not become contaminated even if it comes into contact with moisture-rich foods. ,
Even if the fine powder is packaged, it will not leak outside or be leached by moisture. Furthermore, since this packaging material is a laminate, it has the advantage of being extremely strong.

Procedural amendment (method) % formula % 1. Indication of the case 1982 Patent application No. 10Mef7f No. 2 Title of the invention Packaging material with controlled air permeability & Person making the amendment Relationship to the case Patent applicant address 18-12 Asahi-cho, Sagamihara City, Kanagawa Prefecture Name Fujishima Daishibe Principal Agent Address: 151-5 Date of amendment order Voluntary 6 Target of amendment Full text of specification

Claims (1)

[Claims] (1) A large number of pores are formed on the heat-sealable film surface to form a breathable heat-sealable film, and the desired ventilation is created on the heat-resistant film surface, which has a high melting point, as well as this heat-sealable film. A packaging material with controlled air permeability, which is formed by forming a packaging film with controlled air permeability by perforating pores of a size and number according to the gender, and then laminating and adhering both films.