JP2000238784A - Plastic bottle - Google Patents

Abstract

An object of the present invention is to provide an inexpensive plastic bottle using a recycled material which is extremely low in elution of adsorbed substances and low molecular weight substances into contents and is environmentally excellent. A plastic thin film containing a recycled material has an inner surface coated with a ceramic thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic bottle containing recycled materials.

[0002]

2. Description of the Related Art Plastic bottles having characteristics of being lightweight and hard to be broken are widely used as bottles for storing various contents including foods. In particular, polyethylene terephthalate bottles produced by stretch molding have excellent transparency and mechanical strength and are inexpensive, so they are used as bottles for storing various contents including soft drinks. I have.

[0003] In recent years, efforts have been made to reduce, recycle, and reuse plastic bottles for the purpose of environmental protection. For example, PET (polyethylene terephthalate) bottles containing soft drinks and soy sauce are collected, recycled through pulverization, washing, and granulation processes into school supplies and gift boxes. In addition, recycled materials such as polypropylene trays used for food and materials used for blood collection tubes have begun to be used as toiletry-related bottles.

[0004] However, there are various restrictions on the use of such recycled materials. One of them is a decrease in material properties due to recycling. In the use of recycled materials, deterioration of moldability due to a decrease in viscosity, and reduction of impact resistance and rigidity are often serious problems. Therefore, when a recycled material is used for a toiletry-related bottle, it is generally used by blending with a virgin material.

[0005] Another problem with recycled materials is that
The present invention relates to elution of impurities adsorbed on a material and low molecular weight substances generated by reheating during granulation. For example, a bottle material used as a food bottle adsorbs the components of the food, and various contaminants may be adsorbed to the bottle after the bottle is used. These adsorbed substances are not completely removed in the washing process at the time of recycling, but remain in the recycled material, and when used again as a bottle, the adsorbed substances may elute into the contents.

As a means for reducing the elution of the adsorbate, there is generally a multilayer molding. That is, a method in which a resin layer of a virgin material is provided inside a resin layer in which a recycled material is used. However, even if this method is used, the elution of the adsorbed substance is incompletely prevented, and the production cost increases.

[0007]

The problem to be solved by the present invention is to provide an inexpensive plastic bottle using an environmentally superior recycled material in which the adsorbate or low-molecular-weight substance elutes very little into the contents. Is to do.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the invention of claim 1 is characterized in that a plastic thin film containing a recycled material is coated with a ceramic thin film on an inner surface thereof. It is a plastic bottle.

According to a second aspect of the present invention, there is provided the plastic bottle according to the first aspect, wherein the ceramic thin film is a film containing silicon oxide as a main component.

A third aspect of the present invention is the plastic bottle according to the first or second aspect, wherein the recycled material and the virgin material are both polyethylene terephthalate resins.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A plastic bottle of the present invention will be described below in detail based on one embodiment. The present invention
An object of the present invention is to solve the above-mentioned problem by applying a ceramic thin film coating to the inner surface of a plastic bottle containing a recycled material. In addition, by making the ceramic thin film a film containing silicon oxide as a main component, the elution of low molecular weight components and fat components caused by thermal degradation of the resin can be significantly suppressed. Furthermore, by using a bottle made of polyethylene terephthalate resin as a bottle, the denseness of the ceramic thin film is improved, and higher elution prevention properties are exhibited.

FIG. 1 is a partial sectional view of a container showing one embodiment of the present invention. The material of the bottle 1 is a blend of 70% polyethylene terephthalate virgin material and 30% recycled material, and the inner surface of the bottle 1 is coated with a silicon oxide (SiO _x ) thin film 2 having a thickness of 30 nm.

One of the important features of the present invention is that a plastic thin film containing a recycled material is coated on the inner surface with a ceramic thin film. A recycled material is a material that is collected after being used at least once as a product and reused. The greater the amount of recycled material used per bottle, the more environmentally friendly it is desirable. However, it is preferable to determine the recycled material in consideration of the physical properties and moldability of the bottle.

The ceramic thin film coated on the inner surface may be a film mainly composed of silicon oxide, a film mainly composed of carbon, or alumina.
Although not limited thereto, it is preferable to use a film containing silicon oxide as a main component, because elution of low molecular weight components and fat components caused by thermal degradation of the resin can be significantly suppressed.

[0015] The material of the bottle is not particularly limited either. Polyethylene terephthalate resin, polyethylene resin,
Polypropylene resin, polystyrene resin, polycarbonate resin, polyvinyl acetate resin, nylon resin,
A saponified resin of an ethylene-vinyl acetate copolymer or the like can be used, and the structure can also be a blend of a virgin material and a recycled material of these resins, or a multilayer structure.

A method of coating the inner surface of the bottle with a ceramic thin film is also optional. One example is a method in which a monomer gas is introduced into the inside of the bottle and the ceramic thin film is formed by a plasma-assisted CVD method.

For example, in order to form a thin film containing silicon oxide as a main component using a plasma-assisted CVD method,
Monomers include 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethoxysilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, and phenyl Silane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane,
Phenyltrimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane, and the like can be used.

The organic silicon compound, which is a liquid, is vaporized, and oxygen or a gas having an oxidizing power (for example, N 2
₂ O, CO ₂ etc.), or a mixture of the above mixed gas with an inert gas of helium and / or argon, or nitrogen, carbon fluoride, etc.
Plasma-assisted C with plastic bottle
The thin film containing silicon oxide as a main component can be formed by introducing the thin film into a VD device.

[0019]

EXAMPLES The plastic bottle of the present invention will be described in detail with reference to examples.

<Example 1> A PET bottle used as a bottle for orange juice is collected, and a recycled PET resin material 30 manufactured through a crushing, washing, and granulating process.
% Blended with 70% PET material of virgin to form a stretched PET bottle of 500 ml capacity. A thin film containing silicon oxide as a main component was formed on the inner surface of the bottle using a plasma-assisted CVD method. The source gas used was
It was a mixed gas of hexamethyldisiloxane and oxygen, and the mixing ratio was 1:10.

This bottle is filled with ether,
After storage for 4 hours, the amount of D-limonene eluted into ether was analyzed by gas chromatography. Table 1 shows the analysis results.

Example 2 A bottle having a capacity of 500 ml was formed by blow molding using a blend of 30% recycled polypropylene resin material and 70% virgin polypropylene resin material. A thin film containing silicon oxide as a main component was formed on the inner surface of the bottle using a plasma-assisted CVD method. The source gas used was a mixed gas of hexamethyldisiloxane and oxygen, and the mixing ratio was 1:10.

The bottle was filled with n-heptane and stored at room temperature for 24 hours, and the amount of decane eluted into n-heptane was analyzed by gas chromatography. Table 1 shows the analysis results.

Example 3 A thin film of diamond carbon was formed on the inner surface of a bottle in the same manner as in Example 1 except that a mixed gas of methane, hydrogen, and argon was used as a raw material gas. The mixing ratio of each gas was 4: 2: 10.

This bottle is filled with ether,
After storage for 4 hours, the amount of D-limonene eluted into ether was analyzed by gas chromatography. Table 1 shows the analysis results.

<Example 4> A two-layer multi-layer bottle was blown using a blend of 30% recycled polypropylene resin and 70% virgin polypropylene resin used in Example 2 as an outer layer and a virgin polypropylene resin as an inner layer. Manufactured by molding. A thin film containing silicon oxide as a main component was formed on the inner surface of the bottle using a plasma-assisted CVD method. The source gas used was a mixed gas of hexamethyldisiloxane and oxygen, and the mixing ratio was 1:10.

This bottle was filled with n-heptane and stored at room temperature for 24 hours, and the amount of decane eluted into n-heptane was analyzed by gas chromatography. Table 1 shows the analysis results.

Comparative Example 1 The PET bottle prepared in Example 1 was filled with ether, stored at room temperature for 24 hours, and the amount of D-limonene eluted into the ether was analyzed by gas chromatography. Table 1 shows the analysis results.

Comparative Example 2 The polypropylene bottle produced in Example 2 was filled with n-heptane and stored at room temperature for 24 hours, and the amount of decane eluted into n-heptane was analyzed by gas chromatography. Table 1 shows the analysis results. From the table, it can be seen that the elution amount is smaller in the examples of the present invention than in the conventional example.

[0030]

[Table 1]

[0031]

The plastic bottle containing a recycled resin having a ceramic thin film on the inner surface according to the present invention has a small amount of impurities contained in the recycled resin and elution into low-molecular-weight contents. An inexpensive plastic bottle that does not impair the flavor or taste of the contents can be obtained. In addition, since a large amount of recycled materials can be used, the plastic bottle is also suitable for environmental protection.

[Brief description of the drawings]

FIG. 1 is a sectional view of a part of a container showing one embodiment of the present invention.

[Explanation of symbols]

 1 bottle 2 silicon oxide thin film

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Rei Shirai 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. F-term (reference) 3E033 AA01 BA06 BA13 BA16 BA18 BA21 BA22 BA26 BB08 EA10 3E062 AA09 AB02 AC02 JA07 JB22 JC02 JC04 JD03 4F301 AA25 BF32 4K030 AA06 AA09 AA14 AA16 AA17 BA28 BA44 CA07 CA15 FA01 LA24

Claims (3)

[Claims] 1. A plastic bottle characterized in that a ceramic thin film is coated on an inner surface of a plastic bottle containing a recycled material. 2. The plastic bottle according to claim 1, wherein said ceramic thin film is a film containing silicon oxide as a main component. 3. The plastic bottle according to claim 1, wherein the recycled material and the virgin material are both polyethylene terephthalate resins.