JPS63151451A - Multilayer packaging material - 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] [Industrial Application Field 1] The present invention relates to freshness preservation or deodorization used for packaging foods, etc.
It relates to multilayer packaging materials that have functions such as deodorization.

[Conventional technology 1] Thermoplastic resin wrap films and packaging containers have traditionally been used to package many foods, but recently these materials have been used not only for packaging but also for fresh foods. There is a need for materials with new functions, such as the ability to maintain the freshness of food products and the ability to deodorize odor-smelling products. As a film material having these functions, a film containing a divalent iron compound as the main component and an organic acid component such as 7-scorbic acid has been proposed (Japanese Patent Laid-Open No. 61-611).
0732, JP-A-148236). However, the disadvantages of this film are that the ingredients are expensive, the preparation process of reacting the iron compound and organic acid in an aqueous solution and drying, which is carried out immediately before compounding, is time-consuming, and the durability of the effect is poor. was there.

[Problem to be Solved by the Invention 1] An object of the present invention is to provide a packaging material for foods and the like that uses inexpensive materials and has a freshness-preserving and deodorizing function.

[Means for Solving the Problems 1] As a result of various studies in an attempt to obtain a thermoplastic film that has the function of preserving food freshness and deodorizing it, the inventors of the present invention unexpectedly discovered that the porous film blended inside the film. Based on this knowledge, we added Ike no 8 (fat layer) to a film or sheet containing porous powder to strengthen its strength and give it processability. , the present invention was accomplished.

That is, the present invention is a multilayer packaging material consisting of at least two layers including a thermoplastic O(oil layer) and a porous powder in an amount of 2 to 50% by weight.

The plastic resin layer used in the present invention is not particularly limited as long as it is thermoplastic; Single-layer resin layers such as composites, polyester, nylon, vinyl chloride resins, polystyrene, polyvinylidene chloride, etc., or multi-layer resin layers of two or more of these types can be used as appropriate, and in particular, those having oxygen barrier properties such as ethylene-vinyl alcohol copolymers. A multilayer film of a resin layer and a polyolefin resin layer can be suitably used in terms of preventing deterioration in taste due to oxidation of foods.

Further, in some cases, resins having appropriate oxygen gas permeability or carbon dioxide gas permeability, such as ethyl-Lx-Q-olefin copolymers, may be advantageous in exhibiting porous performance.

The thermoplastic resin layer containing porous powder used in the present invention is a resin layer made of the same resin material as the above thermoplastic resin layer containing 2 to 50% by weight of porous powder. If the content is lower, there will be no freshness-keeping and deodorizing effects, and if the content is higher, the strength and other physical properties of the resin layer will decrease.

In the present invention, the content of porous powder must be kept at 10% by weight or less when transparency is required as a packaging material.

The porous powder used in the present invention has many pores of 2 to 3000 angstroms, that is, the specific surface area is 1.
It is sufficient if it has a content of 0 debris/g or more, preferably 20iv2/g or more, more preferably 50z2/g or more,
Below this value, the effects of deodorization and freshness preservation are reduced.

There are no particular restrictions on the particle size and material of the porous powder, but a particle size of, for example, 100 to 3,000 mesh, preferably 200 to 2,000 mesh, can be used. For example, zeolite, shirasu, silica, activated alumina, montmorinite, activated carbon, Oya stone, cristobalite, etc. can be used, and those with high carbon absorption capacity are desirable.

The porous powder of the present invention has the effect of removing trace amounts of ethylene gas generated during storage of vegetables, fruits, etc., and also has the effect of removing malodorous gases such as ammonia and making them odorless.

In the present invention, the particle size of the porous powder, together with its content, affects the physical properties such as strength or workability of the multilayer packaging material, so it is desirable to select the particle size appropriately from this point of view.

Furthermore, if desired, trace amounts of metal oxides such as titanium oxide, iron oxide, calcium oxide, sodium oxide, etc. may be added to these porous powders, or they may be treated with electromagnetic waves or ozone to maintain freshness and deodorize. The effect can be increased.

Furthermore, fillers, colorants, antioxidants, and the like may be added to the two resin layers of the present invention as appropriate.

Furthermore, it is advantageous to use a foamed lubricant layer with the addition of a foaming agent because it further exhibits the freshness-keeping or deodorizing effect of the porous powder.

In the thermoplastic 81 resin layer containing porous powder used in the present invention, the greater the amount of the powder filled, the lower the mechanical strength of the resin layer, processability such as heat sealing, and adhesiveness. In order to reinforce the material, a thermoplastic #A (fatty layer) containing substantially no filler is laminated, and the resin layer serves as an adhesive layer between the metal thin film or the thermosetting resin layer. It plays a role.

The lamination method used in the present invention is to simply laminate a resin layer containing porous powder and a thermoplastic resin layer, or to laminate a thermoplastic resin layer on the front and back sides with a resin layer containing porous powder sandwiched therein. and additional pond functions, such as special mechanical or heat resistance, as well as oxygen barrier, carbonic acid,
Another resin layer or thin metal layer can be laminated in an appropriate order to impart oxygen adsorption ability or the like.

When using the multilayer packaging material of the present invention for the purpose of deodorizing and removing ethylene inside food packaging, it is advantageous in terms of absorption efficiency to use a resin layer containing porous powder on the inside to remove odors. When used for the purpose of preventing ethylene from escaping into the packaging, or preventing ethylene generated outside the package from permeating inside, such as in the case of a refrigerator, it is recommended to create a sandwich structure inside the porous layer to prevent moisture from forming. It is advantageous in that the quality adsorption function does not deteriorate rapidly.

The multilayer packaging material of the present invention can be manufactured by laminating separate resin layers, but each resin layer can be manufactured by melting and kneading the raw materials for the resin layer in several extruders, and forming a rubber layer for inflation molding and T-Gui molding. It can be easily manufactured by extruding the molten resin through a multi-layered discharge port of the inner adhesive type or the outer adhesive type, and is usually manufactured in the form of a film or sheet with a thickness of 0.01 to 3 U. Furthermore, multilayer containers can be manufactured from this film or sheet by thermoforming, and hollow containers can be manufactured by blow molding.Such containers can be made from the multilayer packaging material of the present invention. be.

The ratio of the thickness of the porous powder-containing resin layer and the thermoplastic resin layer of the multilayer packaging material of the present invention can be selected within the range of 98; 2 to 30 nia. This layer ratio can be appropriately selected depending on the thickness of the multilayer packaging material and the required mechanical strength, heat sealability, type of packaged article, freshness retention, deodorization performance, etc. depending on the application.

[Effect of the invention 1] By using inexpensive materials, the present invention has the function of deodorizing and deodorizing, as well as the function of preserving the freshness of vegetables and fruits, and has excellent appearance, printability, and strength. It is a multilayer packaging material that can be easily imparted with properties and is excellent for use in food packaging, garbage bags, etc.

[Example 1 The present invention will be explained in more detail with reference to Examples.

Examples 1 to 7 The resin raw materials and thermoplastic resin containing porous powder shown in the table were each supplied to two extrusion molding machines, and after melting and mixing, they were introduced into a circular gouie with adhesive inside the gou, and extruded and blown. A two-layer film was produced by inflation molding at a ratio of 3. The measured physical properties of this film are shown in the table.

The tensile strength in the table is expressed as the breaking load of the film in 10zIv.

With the porous powder-containing layer of this two-layer film on the inside,
I made a bag.

This bag had a good appearance.

Next, using this bag, broccoli was packaged and stored for 2 days. The results are shown in the table.

Also, after increasing the volume of the bag to about 40ρ, add ammonia (0,15
A deodorization test was carried out by enclosing 1% solution) and evaluating the odor by opening the container after 124 hours. The results are shown in the table.

Example 8 Zeolite) (200 mesh, specific surface area 300z2/
A multilayer packaging material consisting of a two-layer sheet of a 200μ polypropylene layer and a 50μ polypropylene layer containing 10% by weight of g) was thermoformed to make a tray, broccoli was placed on the tray, and the top surface was sealed with a polyethylene film. I stored it for 2 days, but no yellowing occurred. Evaluation of the test in Example 1) was carried out as follows.

Freshness retention ◎: No yellowing ○: Partial yellowing △: More than half yellowing ×: Full yellowing Deodorizing properties ◎: No odor ○: @Odor △: Slight odor ×: Large odor comparison example 1, comparison Example 2 A test similar to that in the example was conducted on a single layer film made of the resin shown in the table. The test results are shown in the table.

The symbols in the table indicate the following.

LLDPE (1): Polyethylene manufactured by Idemitsu Petrochemical Co., Ltd. Product name Idemitsu Polyethylene LO134H (density 0.
920, MI 1.0) LLDPE (2): Polyethylene manufactured by Idemitsu Petrochemical Co., Ltd. Trade name Idemitsu Moatic 01381 ((density 0,920, Ml 1.0) and LLDP
E(] ),! : ty> Equivalent amount of blend Pl: A small amount of quartz and metal oxides such as titanium oxide and calcium oxide are added to cristobalite powder, kneaded, granulated, dried, fired at around 700°C, and irradiated with electromagnetic waves. It is ground to 300 mesh or more, and has a specific surface area of 65z'/! 9
has.

P2:

Claims (1)

[Claims] 1 A thermoplastic resin layer and at least 2 components including a thermoplastic resin layer containing 2 to 50% by weight of porous powder.
Multilayer packaging material consisting of layers.