JPH05117456A - Propylene polymer film - Google Patents

Abstract

PURPOSE:To provide a propylene polymer film suitable for packing or packaging use, especially for the innermost layer of a laminated bag for packing or packaging thermally sterilized foods, and remarkably improved in smell and freeness from a change in the flavor and taste of a packed (or packaged) material. CONSTITUTION:A propylene polymer film which consists of 100 pts.wt. crystalline propylene polymer and 0.01-1 pt.wt. fraipontite powder having a mean particle diameter of 10mum or smaller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is suitable for filling or packaging applications, particularly for the innermost layer of a heat-sterilized food filling or packaging laminated bag, in view of the change in flavor of the odor and the filling (or packaging) object. It relates to a significantly improved propylene polymer film.

[0002]

2. Description of the Related Art Polypropylene film is widely used as a packaging material, and is used, for example, as the innermost layer of a laminated bag (retort packaging bag) for filling heat-sterilized food or packaging.

[0003] Retort foods have been particularly frequently used in recent years because they are easy to cook, store, carry and dispose of and can be purchased in small quantities, and the demand for them tends to grow. For the sterilization, a high-retort sterilization method (HTST method), which is a high-temperature short-time sterilization, is being adopted in order to suppress changes in quality such as vitamins, color tone and flavor in foods.

However, when the polypropylene film is used as the innermost layer of the retort packaging bag, there is a problem that the odor peculiar to polypropylene impairs the taste of the food and reduces the value of the food, which is more remarkable by the sterilization process by the HTST method. Therefore, there is a strong demand for a solution to this problem.

As a method for reducing the odor of polypropylene, a method of blending tocopherol (Japanese Patent Publication No. 57-
No. 42034) and a method of reducing the residue of volatile components (Japanese Patent Laid-Open No. 80433/1990).

However, the polypropylene film used as the innermost layer of the retort packaging bag is usually subjected to corona discharge treatment in order to impart adhesiveness to other substrate films, but this treatment further increases odor. growing. Therefore, the effect of reducing the odor is insufficient by the above-mentioned conventional methods, and therefore, a satisfactory polypropylene film has not yet been developed.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an odor which does not impair the flavor of a filled (or packaged) product when it is used for filling or packaging, especially as the innermost layer of a retort packaging bag. Is to provide a propylene polymer film which is significantly improved.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made by finding that the above object can be achieved by compounding a crystalline propylene polymer with a specific amount of flypontite powder.

That is, the present invention relates to "a propylene polymer film characterized by comprising 100 parts by weight of a crystalline propylene polymer and 0.01 to 1 part by weight of fly-pontite powder having an average particle size of 10 µm or less". is there.

The crystalline propylene polymer used in the present invention is a homopolymer of propylene and a copolymer resin of propylene as a main component and α-olefin other than propylene having 20 or less carbon atoms such as ethylene and butene in a minor proportion. including.

Of these, a propylene-ethylene block copolymer resin is preferable, and a propylene-ethylene block copolymer resin containing an ethylene component in an amount of 2 to 15% by weight is particularly preferable. The melt flow rate (MFR) of these propylene-based resins is not particularly limited as long as it can be molded, but among them, 1 to 10 g / 10 min is preferable from the viewpoint of film molding.

Further, the fly pontite powder used in the present invention is mainly composed of zinc bifluorosilicate or aluminum zinc fluorosilicate.

This has a basic skeleton of a two-layer structure in which a tetrahedral layer of SiO _{4 and} an octahedral layer of ZnO ₆ are combined in a layered structure, and a part of Si in the tetrahedron of SiO ₄ is Al. Substitution, and corresponding to this valence, part of ZnO ₆ octahedron Zn is also substituted with Al.

The basic chemical structure of this fly pontite is given by the following formula (1). (Zn ₃ -x Al _x ) (Si _2-x Al _x ) O ₅ (OH) ₄ (1) Here, x is typically 0 to 1.8, but the fly pontite used in the present invention is The powder preferably has x of 0.2 to 0.8.

The flypontite powder used in the present invention must have an average particle size of 10 μm or less, preferably 6 μm or less. Flypontite powders exceeding this particle size range are not preferable because the appearance of the film deteriorates.

This special flypontite powder can be appropriately selected and used from commercially available products. The lower limit of the average particle size is about 0.5 μm.

The mixing ratio of the propylene-based resin and the flypontite powder is 0.01 to 1 part by weight, preferably 0.1 to 0.5 part by weight, of 100 parts by weight of the propylene-based resin. It is a department.

When the amount of the flypontite powder is less than the above, the effect of improving odor is insufficient. Further, if the blending amount exceeds the above range, the film appearance is deteriorated, which is not preferable.

In the present invention, in addition to these essential components, stabilizers and processing aids usually used for rubber and polyolefins can be added in an amount that does not impair the effect.

Particularly, in 100 parts by weight of the propylene resin,
By adding 1 to 20 parts by weight of ethylene-α-olefin copolymer rubber, the heat-sealing property and impact strength of the film can be improved. Preferred ethylene-α
-As the olefin copolymer rubber, α-olefin,
Propylene, 1-butene and 4-methylpentene are preferable, and propylene or 1-butene is particularly preferable. Among them, ethylene-α having an ethylene content of 65 to 85 mol%
-Olefin copolymer rubber is most suitable.

The film of the present invention contains the above components,
It is obtained by kneading and molding. As a mixing method, it is preferable to use a known powder mixer, for example, a V-type blender, a Henschel mixer, a ribbon blender or the like, to mix and knead to pelletize. Alternatively, the flypontite powder may be blended in a larger amount than the target amount, and may be diluted with a propylene resin during film formation and used.

As a film forming method, a conventional T-die method is generally used. Further, it is preferable that one surface of the obtained film is subjected to corona discharge treatment for the purpose of imparting adhesiveness to other materials.

The film of the present invention is suitable as the innermost layer of a retort packaging bag. For example, the film of the present invention is used as the innermost layer and an aluminum foil and a polyester film are attached to each other and used as a package for retort foods. ..

[0024]

[Example] The evaluation method is as follows. 1) Evaluation of the odor of the film Put 40 g of the cut film in a 250 ml wide-mouthed bottle, seal it, and adjust the condition for 60 minutes in an oven set at 80 ° C, and then quickly take out the odor of the gas phase part in the wide-mouthed bottle. Was evaluated. The judgment was made by 5 panelists based on the following criteria, and the average value was obtained. 1: Odorless. 2: A faint smell. 3: It clearly smells. 4: Smell strongly.

2) Evaluation of taste after retort Using pure water as a control, the taste was judged by five panelists based on the following criteria, and the average value was calculated. 1: No difference from pure water. 2: A little different from pure water. 3: Clearly different from pure water. 4: Very different from pure water.

Examples 1 to 4 100 parts by weight of a propylene-ethylene block copolymer resin having an MFR of 3.5 g / 10 minutes and an ethylene content of 4% by weight, 10 parts by weight of an ethylene-propylene copolymer rubber having an ethylene content of 70 mol% and Flypontite powder having an average particle size of 4 μ was added in the mixing ratio shown in Table 1, and 0.2 parts by weight of tris (2,4-di-t-butylphenyl) phosphite as an antioxidant and tetrakis [methylene- Three
-(3,5-Di-t-butyl-4-hydroxyphenyl) propinate] methane 0.10 part by weight, and calcium stearate 0.05 part by weight as a hydrochloric acid catching agent were mixed respectively, and after mixing for 2 minutes with a super mixer. ,
The mixture was melt-kneaded at 240 ° C. with an extruder having a diameter of 30 mm and pelletized. 3 with T-shaped die using this pellet
An unstretched film having a film thickness of 60 μ was obtained at 250 ° C. with an extruder having a diameter of 5 mm. Here, the films of Examples 2 and 4 were subjected to a 40 dyne corona discharge treatment on one side.
The odor of these films was evaluated.

Comparative Examples 1 and 2 Evaluation was carried out in the same manner as in Example 1 except that the flypontite powder used in Example 1 was not added. In addition,
In Comparative Example 2, corona discharge treatment was performed on one surface of the film.

Application Example 1 An aluminum foil having a thickness of 9 μm and a polyethylene terephthalate film having a thickness of 12 μm were laminated on the film obtained in Example 4 by using a urethane adhesive as an intermediate layer of the aluminum foil, A bag having a size of 130 mm × 170 mm having the film layer of Example 4 as the inner surface was prepared from this laminated film. 200 cc of pure water was filled in this bag, and retort treatment was carried out at 125 ° C. for 20 minutes in a retort sterilizer. The taste of the pure water was evaluated. The results are shown in Table 2.

Comparative Application Example 1 Table 2 shows the results of evaluation in the same manner as in Application Example 1 except that the film obtained in Comparative Example 2 was used instead of the film obtained in Example 4.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

EFFECTS OF THE INVENTION Since the film of the present invention is composed of specific components, it exerts a remarkable effect of suppressing odor and change in flavor of the object to be filled (or the object to be packaged).

Claims (3)

[Claims] 1. A propylene polymer film comprising 100 parts by weight of a crystalline propylene polymer and 0.01 to 1 part by weight of a Fly Pontite powder having an average particle size of 10 μm or less. 2. The propylene polymer film according to claim 1, wherein the crystalline propylene polymer is a propylene-ethylene block copolymer resin having an ethylene content of 2 to 15% by weight. 3. The propylene polymer film according to claim 2, wherein the propylene-ethylene block copolymer resin is a resin having a melt flow rate of 1 to 10 g / 10 min.