JP2003145679A - Plastic container having thin film layer and thin film layer forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic container having a thin film layer further enhancing the adhesion preventing function of content applied to a conventional container, enhancing user's profit by still more reducing the residual amount of the content and capable of corresponding to a use wider than before in consideration of the safety of a recipe. SOLUTION: In the plastic container 10 of which the inside layer coming into contact with content comprises a polyolefinic thermoplastic elastomer 12, the polyolefinic thermoplastic elastomer 12 is coated with a thin film 13 by generating the gaseous plasma of a silane type monomer gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic container having a thin film layer capable of improving the liquid adhesion on the inner surface and reducing the remaining amount of the contents, and a method for forming the thin film layer.

[0002]

2. Description of the Related Art Recently, a plastic container has been used as a packaging container in various fields such as the food field and the pharmaceutical field because of its various characteristics such as ease of molding, light weight, and low cost. Widely used. One of the characteristics required of the container is how to reduce the residual amount of the content after use. Especially in the case of containers processed by blow molding or injection molding, and paper containers with a structure in which plastic is laminated on the inner surface, it is difficult to extrude the contents while crushing the container, so it is difficult to prevent the contents from adhering to the inner surface of the container and water repellency. It has been devised to provide slipperiness.

Most of them are constituted by a method of coating a fluorine-based resin or a silicone-based resin on the inner surface of the container or kneading and extruding the resin for the inner layer to obtain the adhesion preventing property of the contents. However, the range of use has been limited due to concerns about compatibility with the resin to be blended, compatibility with fluidity, and elution of the coating agent into the contents.

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, the function of preventing adhesion of the contents, which has been applied to a conventional container, is further improved, and the residual amount is further reduced to improve the user's profit, and In view of the safety of prescription, it is an object of the present invention to provide a plastic container that can be used in wider applications.

[0005]

According to a first aspect of the present invention, in a plastic container in which an inner layer in contact with a content is a thermoplastic polyolefin-based elastomer, a silane-based monomer gas is plasma-converted into the thermoplastic polyolefin-based elastomer. It is a plastic container having a thin film layer characterized by being coated with a thin film.

The invention according to claim 2 is characterized in that the thermoplastic polyolefin-based elastomer is a polymer alloy of polypropylene and ethylene-polypropylene copolymer rubber, and the plastic container having a thin film layer according to claim 1. Is.

The invention according to claim 3 is the plastic container having a thin film layer according to claim 1, wherein the silane-based monomer gas is hexamethyldisiloxane or trimethylsiloxane.

Further, in the invention according to claim 4, a plastic container whose inner layer in contact with the contents is a thermoplastic polyolefin-based elastomer is arranged in a space surrounded by external electrodes, and the internal electrode is provided inside the plastic container. A plastic characterized by inserting a silane-based monomer gas between the inside of the container and the internal electrode, applying a high frequency between the both electrodes, and plasmaizing the monomer gas to coat the inside of the container with a thin film. It is a method for forming a thin film layer of a container.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Among general-purpose resins, olefin resins are known to be highly water-repellent resins. The olefinic thermoplastic elastomer made based on this olefinic resin is characterized in that it has physical properties close to those of rubber and has the same processability as plastics. It is known that when an olefin-based thermoplastic elastomer is dissolved and flowed, undulating undulations occur on the surface, which increases the surface area and increases the surface energy, thereby further increasing the water repellency. Since the water repellency becomes higher as the surface becomes more rugged, the desired water repellency can be obtained depending on the processing conditions. However, when the content is a liquid containing a chemical such as a surfactant, the water repellency is deteriorated due to the penetration of the chemical into the polyolefin-based thermoplastic elastomer. In addition, there is a concern that chemicals such as antioxidants added to the thermoplastic polyolefin-based elastomer may be eluted into the contents, so that the use of this formulation would be limited.

Here again, the factors that cause water repellency will be omitted. Chemical factors based on the presence or absence of polar groups in the material itself, and physical factors based on the increase in surface energy represented by the lotus leaf surface shape. It can be classified into two.

Therefore, the inventor, as shown in FIG. 1, has a silicon oxide (1) which prevents the permeation of chemicals on the surface of the thermoplastic polyolefin-based elastomer (12) inside which is in contact with the contents.
By inventing a plastic container (10), the physical water repellency of the thermoplastic polyolefin-based elastomer can be constantly utilized by forming the coating of 3).

Further, the plastic container (10) is
In the high-frequency plasma device shown in FIG. 2, a plastic container (10) having an olefin thermoplastic elastomer on the inner surface of the plastic container is placed inside an external electrode (21) having a cylindrical shape, and the inside of the container is cylindrical. Insert a shaped internal electrode (22), supply a monomer gas mainly composed of siloxane bonds between the inner surface of the container and the internal electrode (22), and apply a high frequency between the electrodes (21, 22),
It is prepared by a method in which each of the surface protrusions of the thermoplastic polyolefin-based elastomer is covered with a glass-like film by converting the monomer gas into plasma. This film itself is not easily attacked by the contents, and in order to prevent it from penetrating into the resin, it becomes possible to permanently maintain the surface shape of the polyolefin-based thermoplastic elastomer and maintain the water repellency, and the contents remain It is now possible to supply containers with reduced volume.

The container having the polyolefin-based thermoplastic elastomer on its inner surface is a single-layer or multi-layer container by blow molding, or a single container by injection molding, a container in which a sheet-shaped polyolefin-based thermoplastic elastomer is vacuum-formed, and insert injection molding thereof. And a paper container made by laminating a polyolefin thermoplastic elastomer on paper. In the case of a multilayer container, polyethylene, polypropylene, polyester, polystyrene or the like may be combined via an adhesive resin or the like according to the purpose and function and arranged in the outer layer.

As a resin used as the above-mentioned thermoplastic polyolefin-based elastomer, a polymer alloy of polypropylene and ethylene-polypropylene copolymer rubber is known, and Zelas ^{TM of} Mitsubishi Chemical Co., Ltd., Montel Co., Ltd.
Adflex of this corresponds to this.

As the gas used in the high frequency plasma apparatus, a mixture of a monomer mainly containing a siloxane bond with oxygen or nitrogen, or argon can be used. Hexamethyldisiloxane and trimethylsiloxane are commonly used as the monomer mainly composed of this siloxane bond.

The embodiment of the present invention will be described with reference to the layer configuration diagram and actual numerical data. Example> (The layer structure is shown in FIG. 3) A container having a 500 ml insert volume and a high-density polyethylene unit, which is made of ZEROS ^™ of Mitsubishi Chemical Co., Ltd., whose outer layer is high-density polyethylene and whose inner layer is polyolefin elastomer A container with the same shape and the same capacity was prepared. The layer ratio was 1 inner layer to 9 outer layers.

As shown in FIG. 2, the inside has a cylindrical shape, and the insulator (2
Place this container through the set member consisting of 3),
Inside the container, the internal electrode (2
2) was inserted. Hexamethyldimethylsiloxane was added to the inside of the container through a gas inflow pipe (24) provided in the internal electrode (22) at 10 sccm (Satanard Cub).
ic Centimeter per Minute)
And 500 sccm of oxygen gas were supplied. 0.05 torr inside the external electrode with a vacuum pump while flowing gas
A high frequency was applied between the electrodes for 20 seconds while maintaining a constant pressure, and a silicon oxide film was formed on the inner surface of the container. Then, the weight was measured together with the container in which the film was not formed.

The layer structure of this "Sample A" is shown in FIG.
11a is an outer layer of high-density polyethylene, 12a is a thermoplastic polyolefin-based elastomer, and 13a is a thin film layer of silicon oxide. The layer structure of “Sample B” is shown in FIG.
(B), 11a is high-density polyethylene of the outer layer, 1
2a is a thermoplastic polyolefin-based elastomer, that is, a layer structure in which the sample A is not provided with a thin film layer of silicon oxide. The layer structure of "Sample C" is shown in FIG. 3 (c). 11a is an outer layer of high density polyethylene, 13a is a thin film layer of silicon oxide, that is, Sample A is a layer structure in which a polyolefin-based thermoplastic elastomer is not provided. is there.
The layer structure of “Sample D” is shown in FIG. 3D, which is a single-layer container of high-density polyethylene (11a).

Next, polyoxyethylene and sodium lauryl sulphate were added to the samples A, B, C and D in 10 containers each.
500 ml of a liquid consisting of 80 parts by weight of water and 500 parts by weight of water was injected, and the container was covered with a lid and stored for 6 months in an environment of 40 ° C and 90% RH. After the storage period, leave the cap in an environment of 20 ° C for 1 day, remove the cap, discharge the contents in an inverted position, and 1 minute later, 2
After 3 minutes and 3 minutes, the total weight of the container was measured to determine the residual amount of the contents.

As a result, the plastic container having the inner surface of the polyolefin elastomer coated with the silicon oxide film showed the fastest reduction in the remaining amount. Also, the same sample A,
The B, C, and D containers were filled with ethanol and stored at 40 ° C. for one month, and then elution of the resin additive was confirmed using liquid chromatography. As a result, elution of the antioxidant was confirmed, but the elution amount of the container coated with the silicon oxide film was 1/30 of that of the container without the film.

Table 1 shows the test results.

[0022]

[Table 1]

Comparative Example> High density polyethylene is used for the outer layer, and fluorine-based resin containing hexafluoropropylene and tetrafluoroethylene as the main components is used for the straight chain low density polyethylene, 500PPM, 1000PPM and 2000PP.
The one to which M was added was used. The layer ratio was 9: 1. Without forming a film, the two kinds of contents liquids were stored as in the example, and each was evaluated.

Regarding the residual contents, it was confirmed that the residual amount decreased as the concentration of the fluorine resin added was increased. In addition, in the elution test, in addition to the fact that the antioxidant was confirmed as in the example, white fine particles were suspended in ethanol in the plastic container containing 2000 PPM, which was found to be a fluorine-based resin by infrared spectroscopic analysis. It was The results are shown in Table 2.

[0025]

[Table 2]

An electrode is installed inside a plastic container,
The method of forming a thin film of silicon oxide on the inner surface by plasma polymerization is such that a thin film is formed on the inner layer of the container even if the handle part has a hollow structure as shown in FIG. can do.

[0027]

Industrial Applicability According to the present invention, it is possible to solve the problem of the residual property of the contents that a conventional plastic container had, and to secure the container having the gas barrier property and the elution component property which are the characteristics of the silicon oxide film. And it can be provided at low cost.

[Brief description of drawings]

1A and 1B are views for explaining a plastic container of the present invention, in which FIG. 1A is a sectional view, and FIG. 1B is an enlarged sectional view of part (A).

FIG. 2 is a schematic cross-sectional view of a high frequency plasma device.

FIG. 3 is a structural cross-sectional view of each sample in the example.

FIG. 4 is a cross-sectional view of a plastic container having a handle.

[Explanation of symbols]

10 ... Plastic container 11 ... Outer layer 11a ... High-density polyethylene 12 ... Polyolefin thermoplastic elastomer 12a ... Zelas 13 ... Thin film layer 13a ... Silicon oxide 14 ... Handle 20 ... High-frequency plasma device 21 ... External electrode 22 ... Internal electrode 23 ... Insulation part 24 ... Gas outlet 25 ... Gas outlet

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeyuki Matsuoka             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. (72) Inventor Manabu Tsujino             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. F term (reference) 3E086 AA21 AD06 BA12 BB59 BB74                       CA01 CA28                 4F100 AA20C AK01A AK03B AK05                       AK07B AK62B AK64B AK66B                       AL05B AL09B AN02B BA03                       BA07 BA10A BA10C DA01                       EJ61C EJ622 GB16 GB23                       JB06 JB16B JD02 JK16                       JM02C                 4K030 AA06 AA14 BA44 CA07 CA15                       DA01 FA01

Claims (4)

[Claims] 1. A thin film characterized in that, in a plastic container in which the inner layer in contact with the contents is a thermoplastic polyolefin elastomer, the thermoplastic thermoplastic elastomer is coated with a thin film by plasmaizing a silane monomer gas. Plastic container with layers. 2. The thermoplastic polyolefin-based elastomer is a polymer alloy of polypropylene and ethylene-polypropylene copolymer rubber.
A plastic container having the thin film layer according to 1. 3. The plastic container having a thin film layer according to claim 1, wherein the silane-based monomer gas is hexamethyldisiloxane or trimethylsiloxane. 4. A plastic container whose inner layer in contact with the contents is a thermoplastic polyolefin-based elastomer is placed in a space surrounded by external electrodes, and the internal electrode is inserted into the plastic container, and the inside of the container and the internal electrode are inserted. A method for forming a thin film layer of a plastic container, characterized in that a silane-based monomer gas is supplied between the electrodes, a high frequency is applied between the electrodes, and the inside of the container is covered with a thin film by converting the monomer gas into plasma.