JP4899471B2 - Gas barrier plastic container and manufacturing method thereof - Google Patents

Description

The present invention relates to a gas barrier plastic container whose physical properties such as barrier properties are improved by coating a thin film on the surface of the container by a plasma CVD method, and a method for producing the same.

  Recently, plastic containers are required to have various functions in various fields such as food and pharmaceutical fields. For example, plastic containers are widely used as packaging containers because of their light weight and low cost. However, plastic containers have the property of penetrating low-molecular gases such as oxygen, carbon dioxide, and water vapor, the property of adsorbing low-molecular organic compounds inside, and the property of having elution components such as acetaldehyde. It had a surface that had to be supplemented as a container.

  Various measures have been taken to solve these problems, but all have various problems and have not been completely solved. For example, as one method for reducing the gas permeability of a plastic container, there is a method of laminating or blending a plurality of plastic materials. When these methods are used, the gas permeability can be reduced to a certain extent, but it cannot be reduced to the target gas permeability such as when used in a container that requires a higher barrier property. Also, the cost of the resin used is very high.

  In recent years, a technique for coating a ceramic thin film on the surface of a plastic container has been known. Most of them improve the gas barrier properties by forming a ceramic thin film on the surface of a container made of a single plastic material. By using this technology, it is possible to obtain a plastic container with excellent barrier properties at low cost by molding a container using a relatively inexpensive material and coating the surface of the molded container with a ceramic thin film. it can.

  However, the container is subject to various stresses during use. These include expansion and contraction of the container due to temperature change and moisture absorption, deformation when the container is transported, and the like. This stress is also applied to the thin film on the inner surface of the container and causes the film to peel off. Therefore, a technique has been proposed in which the adhesion between the ceramic thin film and the plastic substrate is improved to prevent the film from peeling. (For example, refer to Patent Document 1).

  For example, in the example of Patent Document 1, there is a proposal to improve the barrier property and adhesion by sandwiching a film having a larger number of carbon atoms than the barrier layer of the silicon oxide thin film between the barrier layer and the substrate. Has been made. However, the present situation is that even if these methods are used, a product having sufficient adhesion and good barrier properties cannot be produced.

Prior art documents are shown below.
JP 7-32531 A

The present invention is intended to solve such problems of the prior art, and has a barrier plastic container with a ceramic vapor deposited on the surface, which has sufficient adhesion to a plastic substrate and excellent barrier properties. And it aims at providing the manufacturing method .

The present invention has been made to solve the above problems, the invention according to claim 1 of the present invention is a gas barrier plastic container in which a thin film is coated on the container surface by the plasma CVD method, methane Is supplied into the 20 sccm chamber to form a carbon film for 1 second. Subsequently, during 1 second, the methane gas flow rate is changed from 20 sccm to 0 sccm, the HMDSO flow rate is changed from 0 sccm to 5 sccm, and the oxygen flow rate is changed from 0 sccm to 100 sccm. The plastic base material was manufactured by supplying the mixture to the chamber while forming a mixed layer for 1 second, and subsequently supplying 5 sccm of HMDSO and 100 sccm of oxygen into the chamber to form a silicon oxide film for 4 seconds. A carbon film as a first layer is coated on top, and an acid as a second layer is coated thereon. A silicon film is coated, and the carbon atom content ratio gradually decreases from the first layer to the second layer between the first layer carbon film and the second layer silicon oxide film, and the silicon atom content ratio and There is a mixed layer of the carbon film and the silicon oxide film in which the oxygen atom content ratio gradually increases from the first layer toward the second layer, and the carbon film, the mixed layer, and the silicon oxide film are formed. It is a gas barrier plastic container characterized in that the film time ratio is 1: 1: 4.
According to the second aspect of the present invention, methane gas is supplied into a 20 sccm chamber to form a carbon film for 1 second, and then the methane gas flow rate is changed from 20 sccm to 0 sccm and the HMDSO flow rate from 0 sccm in 1 second. Supply the oxygen flow rate to 5 sccm while changing the oxygen flow rate from 0 sccm to 100 sccm, and form a mixed layer for 1 second. Then, supply HMDSO at 5 sccm and oxygen into the 100 sccm chamber for 4 seconds to form a silicon oxide film. In the method for producing a gas barrier plastic container in which a carbon film as a first layer, a mixed layer, and a silicon oxide film as a second layer are sequentially coated by a plasma CVD method on a container surface made of a plastic substrate to be formed, The mixed layer has a carbon atom content ratio that gradually decreases from the first layer toward the second layer, The element content ratio and the oxygen atom content ratio are formed so as to gradually increase from the first layer toward the second layer, and the ratio of film formation times of the carbon film, the mixed layer, and the silicon oxide film is 1: It is a manufacturing method of a gas barrier plastic container characterized by being 1: 4.

  The gas barrier plastic container according to the present invention is a gas barrier plastic container in which a thin film is coated on the surface of the container by a plasma CVD method. A carbon film as a first layer is coated on a plastic substrate, and a second film is formed thereon. By coating the silicon oxide film that is a layer, the ceramic thin film does not peel off even when the container is stressed during filling and transportation, so that high barrier properties can be maintained. For example, it is useful as a container for containing an internal solution sensitive to oxygen. In addition, since the carbon film of the first layer can be made as thin as possible by making the thickness of the carbon film as thin as possible, even if it is coated on a PET bottle, it does not affect the recycling appropriateness of the PET bottle. It has the effect.

  An embodiment of the present invention will be described in detail with reference to FIG.

  FIG. 1 is a configuration diagram of a film forming apparatus for forming a gas barrier plastic container according to the present invention.

  An important feature of the present invention is that a carbon film is interposed between a colorless and transparent silicon oxide thin film having a good gas barrier property and a plastic substrate. This carbon film is excellent in adhesion to both the plastic substrate and the silicon oxide thin film.

  The raw material gas for coating the carbon film includes alkanes such as methane, ethane, propane, butane, pentane and hexane, alkenes such as ethylene, propylene, butene, pentene and butadiene, alkynes such as acetylene, and benzene. , Aromatic hydrocarbons such as toluene, xylene and naphthalene, cycloparaffins such as cyclopropane and cyclohexane, cycloolefins such as cyclopentene and cyclohexene, oxygen-containing carbon such as carbon monoxide, carbon dioxide, methyl alcohol and ethyl alcohol Compounds, nitrogen-containing carbon compounds such as methylamine, ethylamine, aniline, and the like can be used. These gases may be used alone, or may be used by mixing with a rare gas such as argon or helium. Although there is no restriction | limiting in particular in the thickness of this carbon film, 2 nm or more and 10 nm or less are desirable. If the thickness is 2 nm or less, sufficient adhesion between the plastic substrate and the silicon oxide film cannot be obtained, and even if the thickness is 10 nm or more, the adhesion is not further improved, and the transparency deteriorates in proportion to the thickness of the carbon film.

The source gas for coating the second layer silicon oxide film is 1, 1, 3, 3
-Tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethoxysilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane , Tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane, etc., especially 1,1,3,3-tetramethyldisiloxane, hexamethyl Disiloxane and octamethylcyclotetrasiloxane are preferred. However, it is not limited to these, Aminosilane, silazane, etc. can also be used.

Any of the above-mentioned organic silicon compounds that are liquid is vaporized and mixed with oxygen or a gas having an oxidizing power (for example, N ₂ O, CO _2, etc.), or helium which is an inert gas in the mixed gas and / or A gas mixed with argon is used.

  The second feature of the present invention is that a mixed layer thereof exists between the first carbon film and the second silicon oxide film. Due to the presence of this mixed layer, the adhesion between the carbon film and the silicon oxide film can be strengthened. This is because a carbon film is first coated on a plastic substrate using a raw material gas for forming a carbon film, and then a raw material gas for forming a carbon film and a raw material for forming a silicon oxide film It can be manufactured by coating a mixed layer using a gas mixture, and finally coating a silicon oxide film using a raw material gas for forming a silicon oxide film. Further, by gradually changing from a source gas for continuously forming a carbon film to a source gas for forming silicon oxide, the film is directed from the first carbon film toward the second silicon oxide film. It is possible to form a mixed layer in which the composition, that is, silicon atoms and oxygen atoms increase and carbon atoms decrease.

  In this way, changing the type of source gas during film formation can be achieved by changing the flow rate of each source gas adjusted by the mass flow controller (MFC) as shown in FIG. 1 showing the embodiment of the present invention. Achieved. In this example, methane gas is used as a raw material gas for forming a carbon film, and the methane gas is supplied to a vacuum chamber for coating a thin film on the surface of a plastic container through the MFC 1 by a plasma CVD method. Hexamethyldisiloxane (HMDSO) and oxygen gas are also supplied into the vacuum chamber through MFC2 and MFC3, respectively, as gases for forming the silicon oxide film. By changing the flow rate of these three MFCs during film formation, it is possible to continuously form the first carbon film, the second silicon oxide film, and the mixed layer formed between them. It becomes.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

<Example 1>
A plastic container made of polyethylene terephthalate resin having a capacity of 500 ml and a weight of 28 g was coated by plasma CVD using an apparatus as shown in FIG. First, methane gas was supplied into a chamber of 20 sccm (20 ml / min in terms of 1 atmosphere), a high-frequency power of 400 watts was applied, and a carbon film was formed for 1 second. Subsequently, the supply of methane gas was stopped, HMDSO was supplied at 5 sccm and oxygen was supplied into a 100 sccm chamber, a high-frequency power of 400 watts was applied, and a silicon oxide film was formed for 4 seconds. As a result of elemental analysis of the formed thin film using an X-ray photoelectron spectroscopic analyzer, oxygen permeability was measured using OXITRAN manufactured by Mocon. As a result, the container was filled with distilled water, capped and capped at 70 ° C. Table 1 shows the results of examining the presence or absence of film peeling when stored for months.

<Example 2>
A plastic container made of polyethylene terephthalate resin having a capacity of 500 ml and a weight of 28 g was coated by plasma CVD using an apparatus as shown in FIG. First, methane gas was supplied into a chamber of 20 sccm (20 ml / min in terms of 1 atmosphere), a high-frequency power of 400 watts was applied, and a carbon film was formed for 1 second. Subsequently, 20 sccm of methane gas, 5 sccm of HMDSO, and 100 sccm of oxygen were supplied into the chamber, and a high-frequency power of 400 watts was applied to form a mixed layer for 1 second. Subsequently, the supply of methane gas was stopped, HMDSO was supplied at 5 sccm and oxygen was supplied into the 100 sccm chamber, a high-frequency power of 400 watts was applied, and a silicon oxide film was formed for 4 seconds. As a result of elemental analysis of the formed thin film using an X-ray photoelectron spectroscopic analyzer, oxygen permeability was measured using OXITRAN manufactured by Mocon. As a result, the container was filled with distilled water, capped and capped at 70 ° C. Table 1 shows the results of examining the presence or absence of film peeling when stored for months.

<Example 3>
A plastic container made of polyethylene terephthalate resin having a capacity of 500 ml and a weight of 28 g was coated by plasma CVD using an apparatus as shown in FIG. First, methane gas was supplied into a chamber of 20 sccm (20 ml / min in terms of 1 atmosphere), a high-frequency power of 400 watts was applied, and a carbon film was formed for 1 second. Subsequently, the methane gas flow rate is changed from 20 sccm to 0 sccm, the HMDSO flow rate is changed from 0 sccm to 5 sccm, and the oxygen flow rate is changed from 0 sccm to 100 sccm in 1 second, and then the high-frequency power of 400 watts is applied and mixed for 1 second. A layer was deposited. Subsequently, 5 sccm of HMDSO and oxygen were supplied into the 100 sccm chamber, a high frequency power of 400 watts was applied, and a silicon oxide film was formed for 4 seconds. As a result of elemental analysis of the formed thin film using an X-ray photoelectron spectroscopic analyzer, oxygen permeability was measured using OXITRAN manufactured by Mocon. As a result, the container was filled with distilled water, capped and capped at 70 ° C. Table 1 shows the results of examining the presence or absence of film peeling when stored for months.

    Below, the comparative example of this invention is demonstrated.

<Comparative Example 1>
A plastic container made of polyethylene terephthalate resin having a capacity of 500 ml and a weight of 28 g was coated by plasma CVD using an apparatus as shown in FIG. A silicon oxide film was formed for 4 seconds by supplying high frequency power of 400 watts by supplying 5 sccm of HMDSO and oxygen in a 100 sccm chamber. As a result of elemental analysis of the formed thin film using an X-ray photoelectron spectroscopic analyzer, oxygen permeability was measured using OXITRAN manufactured by Mocon. As a result, the container was filled with distilled water, capped and capped at 70 ° C. Table 1 shows the results of examining the presence or absence of film peeling when stored for months.

表１は、組成、酸素透過度、密着試験の測定結果を記す。

Table 1 describes the composition, oxygen permeability, and measurement results of the adhesion test.

<Comparison result>
Below, the comparative result of an Example and a comparative example is demonstrated. The gas barrier plastic containers obtained in Examples 1, 2, and 3 showed almost the same value for oxygen permeability, and the gas barrier properties were all good. Further, the adhesion was good and there was no film peeling. The gas-barrier plastic container obtained in Comparative Example 1 had almost the same oxygen permeability as Examples 1, 2, and 3, but had poor adhesion and film peeling.

It is a block diagram of the film-forming apparatus for gas-barrier plastic container formation which concerns on this invention.

Claims (2)

In a gas barrier plastic container in which a thin film is coated on the surface of the container by plasma CVD, methane gas is supplied into a 20 sccm chamber to form a carbon film for 1 second, and then the methane gas flow rate is increased from 20 sccm in 1 second. Supplying to the chamber while changing the HMDSO flow rate from 0 sccm to 0 sccm and changing the oxygen flow rate from 0 sccm to 100 sccm to 0 sccm, forming a mixed layer for 1 second, and then continuing the HMDSO 5 sccm and oxygen into the 100 sccm chamber The carbon film, which is the first layer, is coated on the plastic substrate, and the silicon oxide film, which is the second layer, is coated on the plastic substrate. Contains carbon atoms between one layer of carbon film and second layer of silicon oxide film The carbon film and the silicon oxide film in which the rate gradually decreases from the first layer toward the second layer, and the silicon atom content ratio and the oxygen atom content ratio gradually increase from the first layer toward the second layer A gas barrier plastic container, wherein a ratio of film formation times of the carbon film, the mixed layer, and the silicon oxide film is 1: 1: 4. Methane gas is supplied into the 20 sccm chamber to form a carbon film for 1 second. Subsequently, during 1 second, the methane gas flow rate is changed from 20 sccm to 0 sccm, the HMDSO flow rate is changed from 0 sccm to 5 sccm, and the oxygen flow rate is changed from 0 sccm to 100 sccm. Then, the mixed layer is formed for 1 second, and then the HMDSO is supplied at 5 sccm and oxygen is supplied into the 100 sccm chamber to form a silicon oxide film for 4 seconds to the surface of the container made of a plastic substrate . In the method for manufacturing a gas barrier plastic container in which the carbon film as the first layer, the mixed layer, and the silicon oxide film as the second layer are sequentially coated by the plasma CVD method, the mixed layer has a carbon atom content ratio of 1st. Decreasing gradually from layer to second layer, silicon atom content ratio and oxygen atom content ratio Is formed so as to gradually increase from the first layer toward the second layer, and the ratio of the film formation times of the carbon film, the mixed layer, and the silicon oxide film is 1: 1: 4. A method for producing a gas barrier plastic container.

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