JPS6386757A - Plastic film - Google Patents

Abstract

PURPOSE:To obtain a plastic film, by containing a specific finely divided siliceous inorganic compound in a specific plastic film, used for packaging food, etc., having excellent freshness retaining effect as well as deodorizing effect and capable of preventing blocking. CONSTITUTION:A plastic film obtained by containing (B) 0.5-30wt%, preferably 1.5-15wt% preferably porous siliceous inorganic compound, finely divided to give >=25m<2>/g, preferably 30-1,000m<2>/g surface area and having a particle size in which >=80wt% particles pass through a 100-mesh screen according to JIS-Z8801, preferably glauconite, diatomaceous earth, clay, etc., in (A) plastic capable of giving a film having >=6X10<3>cc/m<2>.24hr.atm CO2 gas permeability when formed into a film of 30mum thickness, preferably 1,2-polybutadiene, polyethylene, ethylene-vinyl acetate copolymer, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a plastic film that is used for food packaging and has excellent freshness-keeping and deodorizing effects.

(Prior Art) Fresh foods often rot or change color during transportation and storage, resulting in a significant decrease in product value due to a decrease in freshness. Conventionally, in order to prevent food spoilage and loss of freshness during the transportation and storage process, there have been methods for freezing and refrigerating fruits, vegetables, seafood, etc., methods for directly applying disinfectants,
The CA storage method (setting the gas composition of the atmosphere to conditions suitable for storage), the method of incorporating an iron-based composition into a plastic film, etc. have been proposed.

(Problems to be solved by the invention) However, there are food hygiene toxicity issues, equipment cost issues, and no method with sufficient effectiveness has been obtained so far, so it is difficult to implement easily. There is a need for the development of a preservation method and deodorization method that is safe for use on fruits, vegetables, and seafood, and has a freshness-preserving and preservative effect.

(Means for Solving the Problem) The inventors have conducted various studies to satisfy the requirements for food preservation, deodorization, and freshness preservation.
When a film with a thickness of 30 μm is used as the packaging material, the COt gas permeability is 6 × 10” cc/rd ・24
A siliceous inorganic compound is added to a plastic having a surface area of 25 nm or higher, preferably a plastic of 1,2-polybutadiene, polyethylene, ethylene-vinyl acetate copolymer, etc., with a surface area of 25 nm or higher. The present invention attempts to solve the above problems by crushing the siliceous inorganic compound to a size of at least 1 g, and then mixing and using the finely divided material. To provide a plastic film which is characterized in that, when used in an appropriate manner, the plastic film does not lose its freshness, remains fresh for a long time, and achieves deodorizing and preservative effects.

The present invention will be explained in detail below.

Preferred specific examples of the resin used in the present invention include 1
．． Examples include 2-polybutadiene, polyethylene, ethylene-vinyl acetate copolymer, styrene-butadiene block copolymer, polyisobutylene, polyvinyl acetate, polyvinyl chloride, polypropylene, etc. Among these, 1,2-polybutadiene is preferable. , polyethylene, and ethylene-vinyl acetate copolymers can be used. Particularly preferably,
1.2-polybutadiene having a 1.2-coupled gold content of 70% or more and a crystallinity of 5 to 50% is used.

The silicic acid inorganic compound has a gas adsorption surface area of 25 m/g or more, preferably 30 to 1000 m/g, as measured by the BET method.
It is possible to use a material made fine so as to have rrf/g, and a porous material is particularly preferable. Regarding the particle size of the siliceous inorganic compound, the amount passing through a 100 mesh sieve according to JIS-Z8801 is 80% by weight or more, preferably 90% by weight or more, and more preferably the amount passing through a 150 mesh sieve is 80% by weight or more, particularly preferably The amount passing through 200 mesh is 80% by weight or more. Preferred specific examples of the siliceous compound include glauconite, diatomaceous earth, clay, zeolite, volcanic glass ore, etc., and more preferred examples include fine particles of glauconite. The content of the above inorganic compounds is 0.5 to 30
% by weight, preferably 1.5-15% by weight.

The plastic film of the present invention may be prepared by kneading the above-mentioned siliceous inorganic compound into a resin in advance using a conventional method such as a mixer or an extruder, and forming the film into a film, or alternatively, it may be formed at the same time as the kneading during film forming. The thickness of the film of the present invention may be uniformly 10 to 300μ, preferably 1
It can be produced by extrusion, injection, blow molding, etc. by casting method, T-die method, inflation method, etc. into a film having a thickness of 5 to 50 μm, particularly preferably 20 to 40 μm.

Note that if the content of the siliceous inorganic compound is less than 0.5% by weight, the freshness retaining effect and deodorizing effect will not be sufficiently obtained;
If it exceeds 0% by weight, the siliceous inorganic compound will segregate, making it impossible to obtain a uniformly dispersed film, and the effect will reach a saturated state. Further, if the thickness of the film is 10 μm or less, it is difficult to form the film, and practical strength cannot be obtained. 300
If the film thickness is more than μ, the proportion of the mixed siliceous inorganic compound present in the surface layer of the film will be low (and it will be difficult to obtain the freshness preservation effect. If the adsorption area is less than 25 m2/g, good effects cannot be obtained.

The plastic film of the present invention not only maintains the freshness of the food described above, but also has the effect of preventing films from sticking together (profking).

For this reason, the bags and the like can be opened extremely easily, and the films can be easily peeled off one by one.

Although it is not necessarily clear why the silicic acid inorganic compound in the plastic film of the present invention has an effect such as maintaining freshness, the effect is that the temperature of the product increases when the plastic film of the present invention is not used. It is thought that the plastic film maintains an appropriate heat absorbing effect, and has a humidity control effect because the adhesion of internal water droplets is good. It is also believed that the siliceous inorganic compound has the property of extremely well capturing ethylene, which is released from foods such as fruits and has an adverse effect on the foods themselves. From these facts, it can be said that the speed of change in quality is suppressed and there is an effect of maintaining freshness. In addition, the physical properties of silicate acidic inorganic compounds are that they are porous, have an extremely large surface area, and have a high gas adsorption capacity (
Since it has such a small amount of charge, it is thought to have a good deodorizing effect.

The plastic film of the present invention can be used for various purposes, for example, it can be suitably used as a packaging material for foods such as fruits and vegetables. It is used to package fruits and vegetables such as eggplant, cucumber, broccoli, shiitake, asparagus, matsutake, beans, and lettuce, and can also be used for other seafood and meat.

Packaging formats include stretch packaging, Shelllink packaging, and cardboard interiors, and methods include storing an appropriate amount in a cardboard box, wooden box, foamed plastic box, etc.

Other uses include shoe insoles, footwear materials, and agricultural films.

(Example) Next, the present invention will be explained in more detail based on examples.

Examples 1 to 7 and Comparative Examples 1 to 5 As described in Table 1, the amount added (wt%) and the surface area (m
Pegasus Green (a type of glauconite, manufactured by Aisink Co., Ltd.) with various concentrations of 2/g) was mixed with various resins having carbon dioxide permeability values listed in Table 1 for a film with a thickness of 30 μm. A plastic film with a thickness of 30 μm was used as an interior bag for a cardboard box. 5 kg of cucumbers (approximately 50 pieces) were used as samples, packed in the interior bag, stored in a cardboard box, and stored at 35°C for 3 days. The percentage (%) and the presence or absence of off-odor were tested. Note that the surface area of Pegasus Green used in the Examples was measured under the following conditions.

Operation: Kuramochi Kagaku BET device Grinding machine: Ishikawa type agate crusher Drying pretreatment: Each sample dried at 110°C for 2 days Sample weight:
Approximately 0.3 to 0.5 g (accurately weighed) Desorption temperature: 120℃, Desorption time: 2 hours Desorption pressure: 10-'mHg Adsorption gas: After purifying high-purity nitrogen gas, adsorption temperature for stool Knee 1
83°C Adsorption time: 2hr Adsorption pressure: 104 Hg Refrigerant: Liquid oxygen Also, carbon dioxide permeability is ASTM, Di 434.
It was carried out at 23°C.

As is clear from Table 1, the surface area of Pegasus Green is 23rd/g without grooves, the plastic used is not an appropriate material, Pegasus Green is not included in the film, the Pegasus Green content is too high, It can be seen that packaging that does not use plastic film is both inferior in freshness preservation and deodorizing effects.

Example 8 and Comparative Example 6 Table 2 shows that broccoli 2 kir and Pegasus Green used in Examples 1 to 7 and Comparative Examples 1 to 5 were mixed with 1°2-polybutadiene resin (RB820 manufactured by Japan Synthetic Rubber Co., Ltd.). The test results are shown below, using a film with a thickness of 30 μm obtained using the same method, packed in a cardboard box, and stored at 25° C. for 4 days, in comparison with a film without the film. The amount of Pegasus Green added, surface area, and permeability are as listed in Table 2.

Claims (4)

[Claims] (1) CO_2 gas permeability when made into a 30 μm thick film is 6×10^3cc/m^2・24hrs・a
Plastic with a surface area of 25 m^2/g that is larger than tm
A plastic film containing 0.5 to 30% by weight of the above finely divided siliceous inorganic compound. (2) The plastic film according to claim 1, wherein the siliceous inorganic compound is at least one selected from glauconite, diatomaceous earth, clay, zeolite, and volcanic glass ore. (3) The plastic film according to claim 1, wherein the plastic is at least one selected from 1,2-polybutadiene, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl chloride, and polypropylene. (4) The silicic acid inorganic compound is JIS-Z8801 10
The plastic film according to claim 1, which has a particle size that allows 80% by weight or more to pass through a 0-mesh sieve.