JP2003165568A - Oriented plastic container having gas absorbency - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic container having a gas absorbing function applied to an inner layer of a multi-layered oriented plastic container structure, which is inexpensive, is free from degradation in mechanical strength and has excellent gas absorbency. <P>SOLUTION: The multi-layered oriented plastic container structure has an inner layer (1) comprising 70 to 40 wt.% of a thermoplastic resin (1a) and 30 to 60 wt.% of a gas absorbing inorganic compound (1b) blended therein. In addition, voids (1c) are formed around the inorganic compound (1b). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-absorbing stretched plastic container, and more particularly to a stretched plastic container in which the inner layer of the container has a function of absorbing gas such as moisture.

[0002]

2. Description of the Related Art Conventionally, plastic containers are used in various fields such as the food field, pharmaceutical field, toiletry field, etc. due to various characteristics such as ease of molding, light weight, and low cost. Widely used as. However, plastic containers have the property of permeating low-molecular-weight gases such as oxygen, carbon dioxide, and water vapor, and are effective for preventing the proteins and fats and oils in the packaged contents from being oxidized or denatured and for the effectiveness of the contents. In order to prevent deterioration of the components, various improvements have been made to prevent entry of low molecular weight gases such as oxygen and water vapor from the outside of the container, and conversely to prevent moisture in the contents from going out of the container. There were many aspects that had to be added. Various measures have been taken to solve these problems. For example, a method of laminating vinylidene chloride resin having gas barrier properties,
Alternatively, there is a method of laminating a mixed resin in which polyethylene glycol and silica gel are mixed with polypropylene resin as an inner layer.

[0003]

However, in the case of laminating vinylidene chloride resin, it is not preferable that chlorine gas is generated in the incineration treatment after use, which causes generation of dioxins. The cost of was also very high. In addition, the method of laminating a mixed resin prepared by mixing polyethylene glycol and silk gel with polypropylene resin as an inner layer has drawbacks such that it becomes brittle and cracks easily occur on the surface, and the mechanical strength decreases.

An object of the present invention is to provide a stretched plastic container structure having a multi-layered structure with a gas-absorbing function, which is inexpensive, has no deterioration in mechanical strength, and has excellent gas-absorbing properties. To provide a container.

[0005]

The invention according to claim 1 of the present invention is a multi-layered stretched plastic container structure, wherein the inner layer is a mixture of a thermoplastic resin and a gas-absorbing inorganic compound, and A drawn plastic container having gas absorbability, characterized in that voids (voids) are formed around the inorganic compound.

Next, the invention according to claim 2 is the stretched plastic container having gas absorbability, characterized in that, in the invention according to claim 1, the inorganic compound is synthetic fluorite.

Next, the invention according to claim 3 is the same as the invention according to claim 1 or 2, wherein the mixture contains 70 to 40% by weight of a thermoplastic resin and 30 to 6% of an inorganic compound.
A stretched plastic container having gas absorbency, which is characterized in that it is composed of a mixture of 0% by weight.

[0008]

According to the present invention, since the inner layer of the container is made of a mixture of a thermoplastic resin and a gas-absorbing inorganic compound, and voids (voids) are formed around the inorganic compound, The inorganic compound easily absorbs moisture, carbon dioxide gas, and other low molecular weight gas from the outside, so that the invasion of these gases into the inside can be prevented.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The stretched plastic container having gas absorbability of the present invention will be described in detail below with reference to embodiments.

FIG. 1 (a) is a cross-sectional view of a stretched plastic container having a gas absorbing property according to an embodiment of the present invention, which has a two-layer structure of an inner layer (1) and an outer layer (2).
(B) is a schematic diagram explaining the structure of the inner layer (1). The inner layer (1) is made of a mixture of a thermoplastic resin (1a) and a gas-absorbing inorganic compound (1b), and has a void (void) (1c) around the inorganic compound (1b) during molding of a container. Are formed.

The voids (voids) (1c) are elongated voids (voids) (1c) around the compounded inorganic compound (1b) by stretching the thermoplastic resin in the mixture during the molding process of the container. Is formed.

The thermoplastic resin (1a) used in the inner layer (1) is an olefin resin such as a low density polyethylene resin, a linear low density polyethylene resin, a medium density polyethylene resin or a high density polyethylene resin, or a polypropylene resin. Polymer resins such as polystyrene resin, polyester resin, and polycarbonate resin can be used, and any resin that can be stretch-molded may be used.

As the inorganic compound (1b), natural zeolite or synthetic fluorite can be used. Particularly, synthetic fluorspar is preferable because it can easily adsorb polar compounds selectively, and particularly strongly adsorbs water. It also adsorbs carbon dioxide and hydrogen sulfide. The particle size of the synthetic fluorspar is preferably 0.5 to 2 μm. The composition of synthetic fluorspar is Na ₂ O ・ Al ₂ O ₃・ S
iO ₂ · H ₂ O ...

It is necessary that the mixture is a mixture of 70 to 40% by weight of the thermoplastic resin and 30 to 60% by weight of the inorganic compound. When the blending ratio of the inorganic compound in the mixture is 30% by weight or less, the gas absorption performance is poor, and when it exceeds 60% by weight, various mechanical strengths of the container are deteriorated, which is not preferable.

The thermoplastic resin used in the outer layer (2) is an olefin resin such as a low density polyethylene resin, a medium density polyethylene resin or a high density polyethylene resin used in the inner layer (1), a polypropylene resin, a polystyrene resin, Polymer resins such as polyester resins and polycarbonate resins can be used, and any resin that can be stretch-molded may be used.

The gas-absorbing stretched plastic container of the present invention can be molded by stretch molding using a known blow molding method, stretch blow molding method, injection molding method, sheet molding method or the like. In these molding methods, the resin is stretched in all cases although there are large and small sizes at the time of molding the container. There are various shapes such as a bottle shape and a tray shape.

[0017]

EXAMPLES The stretched plastic container having gas absorbability of the present invention will be further described with reference to specific examples. The invention is not limited to these examples.

<Example 1> As the inner layer (1), a density of 0.
Using a mixture 910 g / cm ³ polyethylene resin 60 wt% of relative compounded with 40 wt% synthetic fluoride stones, using the outer layer (2) as a non-compounded density 0.910 g / cm ³ of a polyethylene resin, the multilayer stretched Blow molding is performed using a blow molding machine, and the inner layer (1) and the outer layer (2) each have a thickness of 250 μm and a total thickness of 500 μm and an internal volume of 600 ml.
The stretched plastic bottle having gas absorbency of the present invention was prepared.

<Example 2> As the inner layer (1), a density of 1.
Injection molding using a mixture of 50 wt% of 335 g / cm ³ polyester resin and 50 wt% of synthetic fluorspar, and an unblended polyester resin with a density of 1.335 g / cm ³ as the outer layer (2). Machined a preform. This preform was stretch blown by a multi-layer stretch blow molding machine, and the inner layer (1) and the outer layer (2) each had a thickness of 200 μm and a total thickness of 400 μm and an internal volume of 500 ml.
The stretched plastic bottle having gas absorbency of the present invention was prepared.

Comparative Example 1 An internal capacity of 60 was obtained in the same manner as in Example 1 except that the unblended polyethylene resin having a density of 0.910 g / cm ³ was used as the inner layer (1).
A 0 ml comparative stretched plastic bottle was made.

<Evaluation> Using the stretched plastic bottles prepared in Examples 1 and 2 and Comparative Example 1, the water absorption performance of the bottles was measured and evaluated by the following measuring method. The results are shown in Table 1. (1) Water Absorption Performance Measuring Method The stretched plastic bottles prepared in Examples 1 and 2 and Comparative Example 1 were filled with 100 g of calcium chloride (anhydrous),
The mouth portion was sealed with a lid member having a thickness of 20 μm, the surface of which was coated with a hot melt agent. After leaving the bottle for 40 days in an environment of a temperature of 40 ° C. and a relative humidity of 90%,
Visually inspect the presence or absence of moisture absorption of calcium chloride in the bottle,
The water absorption performance of the bottle was evaluated.

[0022]

[Table 1]

From the results shown in Table 1, Examples 1 and 2 showed almost no moisture absorption of the calcium chloride filled in the bottles.
On the other hand, in Comparative Example 1, the calcium chloride filled in the bottle had a large moisture absorption. From the above results, it was found that the bottles of Examples 1 and 2 used a mixture of synthetic fluorspar in the inner layer, so that the synthetic fluorspar absorbed water invading from the outside.

[0024]

The stretched plastic container having gas absorbability of the present invention is a bottle-shaped, tray-shaped, case-shaped, etc. plastic container, and the inner layer of the container is a thermoplastic resin containing a gas-absorbable inorganic compound. Consisting of a mixture of
And, since elongated voids (voids) are formed around the inorganic compound when stretched in the molding process, the gas is easily absorbed and has excellent gas absorbability, particularly water absorbency, and It has features such as long-lasting performance. Therefore, it can be widely used as a plastic container having gas absorbability.

[Brief description of drawings]

FIG. 1 (a) is a cross-sectional view of a stretched plastic container having gas absorption properties of the present invention, and FIG. 1 (b) is a schematic diagram illustrating an inner layer structure of the stretched plastic container of (a).

[Explanation of symbols] 1 ... Inner layer 1a ... thermoplastic resin 1b ... Inorganic compound 1c ... void (void) 2 ... Outer layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyoshi Sawada             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. (72) Inventor Masateru Yamamoto             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. F term (reference) 3E086 AA22 AD04 AD05 BA04 BA15                       BA27 BA33 BA35 BB02 BB03                       BB05 CA01 CA28 CA35                 4F100 AA00A AA00H AK01A AK04A                       AK04B AT00B BA02 CA09A                       DA01 DD22 EJ37 GB16 GB23                       JB16A JD14 JD15

Claims (3)

[Claims] 1. A stretched plastic container structure having a multilayer structure, wherein an inner layer is composed of a mixture of a thermoplastic resin and a gas-absorbing inorganic compound, and voids (voids) are formed around the inorganic compound. A stretched plastic container having gas absorbability, which is characterized in that 2. The stretched plastic container having gas absorbability according to claim 1, wherein the inorganic compound is synthetic fluorite. 3. The gas according to claim 1, wherein the mixture is a mixture of a thermoplastic resin of 70 to 40% by weight and an inorganic compound of 30 to 60% by weight. Stretched plastic container with absorbency.