JP4593213B2 - Gas barrier plastic container and manufacturing method thereof - Google Patents

Description

  The present invention relates to a plastic container. More specifically, the present invention relates to a plastic container having a gas barrier thin film on the entire inner surface of a container body and excellent in gas barrier properties for blocking permeation of oxygen gas, carbon dioxide gas, water vapor, and the like, and a method for manufacturing the same.

Plastic containers have high gas permeability such as oxygen gas, carbon dioxide gas, water vapor, etc., so oxygen gas in the atmosphere enters inside the container, and carbon dioxide and moisture in the contents are released outside the container, and the contents Quality deteriorates. As a gas barrier silent container, a gas barrier container in which a gas barrier layer made of a resin composition having an inorganic layered compound such as graphite, a phosphate derivative compound, a chalcogenide, and a clay mineral is laminated on the inner surface of the container is known. (See Patent Document 1). In addition, a resin film comprising any one of a polyvinyl alcohol-based coating agent, a vinylidene chloride-based coating agent, or an ethylene-vinyl copolymer-based coating agent or a composite thereof, or a resin film containing an alkoxide or an alkoxide hydrolyzate A container having a surface is known (see Patent Document 2). Furthermore, a bottle in which a hard carbon film (DLC) is formed on the inner wall surface of a plastic bottle is known (Patent Document 3). Furthermore, a plastic container having a single layer of a thin film mainly composed of a silicon compound formed on the surface by a CVD method is known (see Patent Document 4, Patent Document 5, and Patent Document 6).
JP 11-314674 A JP-A-8-238667 JP 2003-31670 A Japanese Utility Model Publication No. 5-35660 JP 2000-43875 A JP 2000-117881 A

In the containers described in Patent Document 1 and Patent Document 2, since the gas barrier layer made of the resin composition having an inorganic layered compound is directly exposed to water, the gas barrier layer collapses, and the gas barrier property deteriorates rapidly. There is. In addition, as shown in Patent Document 2, in the case of a plastic container provided with a vinylidene chloride coating agent, if it is disposed of as waste after use, for example, if it is disposed of by incineration, it contains chlorine atoms. Therefore, there is a concern about the impact on the human body due to the generation of toxic gas such as dioxin at the time of incineration disposal. Furthermore, in order to obtain a predetermined barrier property, the container described in Patent Document 3 has to increase the thickness of the hard carbon film, and if the film thickness is increased, the container becomes yellowish brown. There is a problem that the designability of is impaired. Further, in the containers described in Patent Document 4, Patent Document 5 and Patent Document 6, a thin film mainly composed of a silicon compound is a single layer, and a by-product generated during a plasma chemical reaction in a single cycle CVD process is a silicon compound. There is a problem that it is not possible to obtain a high gas barrier property that is originally taken into a thin film mainly composed of. Moreover, in order to obtain a predetermined film thickness, an excessive material gas is introduced, so that the plastic container is deformed or colored, the oxidation reaction of the material gas does not proceed sufficiently, and the material gas becomes mineralized. Therefore, there is a problem that sufficient gas barrier properties cannot be obtained.
An object of the present invention is to provide a plastic container having a high gas barrier property that cannot be obtained by a conventional plastic container having a barrier layer composed of a thin film mainly composed of a single-layer silicon compound, and particularly a plastic container having a high water vapor gas barrier property. It is to provide a manufacturing method.

  The invention according to claim 1 solves the problems related to the plastic container, and is a gas barrier thin film mainly composed of a plurality of layers of silicon oxide formed on the inner surface of the plastic container main body by plasma chemical vapor deposition. The gist of the present invention is a gas barrier plastic container comprising a multilayer gas barrier thin film mainly composed of silicon oxide, in which the oxidation degree of each layer is sequentially reduced from the first layer to the uppermost layer. This gas barrier plastic container is excellent in gas barrier properties, and particularly has a high water vapor barrier property.

A second aspect of the present invention is intended to solve the problems related to the manufacturing method described above, the inner surface of the plastic container body, method of manufacturing a gas barrier plastic container comprising a gas barrier thin film mainly composed of silicon oxide SiO _xn C _yn In this method, a gas barrier thin film mainly composed of a plurality of layers of silicon oxide is formed by a plasma chemical vapor deposition method using a source gas containing an organosilicon compound on the inner surface of the plastic container body. A gas barrier plastic container characterized by forming a multi-layer gas barrier thin film mainly composed of silicon oxide by gradually reducing the plasma discharge output from the first layer to the uppermost layer to sequentially reduce the degree of oxidation of each layer. The manufacturing method is summarized.

  According to the second aspect of the present invention, the plasma discharge output is gradually reduced from the first layer to the uppermost layer when forming each layer, and the introduction amount of the organosilicon compound and the introduction amount of oxygen gas into the reaction vessel are reduced. You may reduce in steps from 1 layer to the top layer.

According to a second aspect of the present invention, in the method for manufacturing a gas barrier plastic container comprising a gas barrier thin film mainly composed of silicon oxide SiO _xn C _yn on the inner surface of the plastic container body, an organosilicon compound is applied to the inner surface of the plastic container body. A gas barrier thin film mainly composed of a plurality of layers of silicon oxide is formed by a plasma chemical vapor deposition method using a source gas containing, and in that case, a plasma discharge output is applied from the first layer to the uppermost layer during the formation of each layer. By gradually reducing the degree of oxidation of each layer and forming a multilayer gas barrier thin film mainly composed of silicon oxide, a multilayer gas barrier thin film mainly composed of silicon oxide is deposited on the inner surface of the plastic container body. It cannot be obtained in a conventional plastic container having a barrier layer made of a thin film mainly composed of a single-layer silicon compound. It is possible to provide a plastic having excellent gas barrier properties, particularly water vapor barrier properties.

  In the present invention, the introduction amount of the organosilicon compound is desirably 6 sccm or less, and the introduction amount of the oxygen gas is desirably 100 sccm or less.

In the present invention, each layer constituting the multi-layer gas barrier thin film mainly composed of silicon oxide has a general formula SiO _xn C _yn (mainly silicon oxide mainly composed of silicon oxide in which at least silicon atoms, oxygen atoms and carbon atoms are chemically bonded). A gas barrier thin film mainly composed of silicon oxide represented by 1.5 <xn ≦ 2.2, 0.01 ≦ yn ≦ 0.5) can be used. This gas barrier thin film mainly composed of silicon oxide is dense, has few gaps, is highly flexible, and has high gas barrier properties.

In the present invention, as a multi-layer gas barrier thin film mainly composed of silicon oxide, the gas barrier thin film mainly composed of the first silicon oxide SiO _x1 C _y1 laminated on the inner surface of the plastic container to the nth silicon oxide SiO _xn C _yn A multi-layer gas barrier thin film mainly composed of silicon oxide is used, in which the xn value of each layer of the gas barrier thin film mainly composed of is reduced and reduced discontinuously with x1>x2>x3>. be able to. This multilayer gas barrier thin film mainly composed of silicon oxide has a water vapor transmission coefficient of 1 to 50 g / m ² · day and imparts a high oxygen barrier property to a plastic container body with a high oxygen barrier property. .

  In the present invention, a polyester resin blow-molded container or a polyolefin resin blow-molded container can be used as the plastic container body.

  In the present invention, it is desirable that the plasma discharge output range at the time of forming each layer be 150 W to 600 W.

  In the present invention, it is desirable that the ratio of the flow rate of the organosilicon compound to the oxygen gas is in the range of 1: 5 to 1:20.

  In the present invention, the total thickness of the multilayer gas barrier thin film mainly composed of silicon oxide is preferably in the range of 20 to 100 nm. When the film thickness is smaller than 20 nm, sufficient gas barrier properties cannot be obtained. On the other hand, if the film thickness is larger than 100 nm, cracks or the like are likely to occur in the film, which is not preferable.

  The gas barrier plastic container according to claim 1 is excellent in gas barrier properties, and particularly has a high water vapor barrier property, and is therefore suitable for packaging of contents containing volatile components such as moisture, such as beverages, foods, pharmaceuticals, and electronic materials. Can be used.

Alternatively, according to the manufacturing method of the invention described in claim 2, the first layer comprises a gas barrier thin film mainly composed of a plurality of layers of silicon oxide formed on the inner surface of the plastic container main body by plasma chemical vapor deposition. By providing a multi-layer gas barrier thin film mainly composed of silicon oxide in which the oxidation degree of each layer has decreased sequentially from the top layer to the top layer, it is mainly composed of silicon oxide having a highly low water vapor transmission coefficient on the inner surface of the main body of the plastic container. By depositing and growing a multilayer gas barrier thin film, it is possible to produce a plastic container having a high gas barrier property that cannot be obtained in a conventional plastic container having a barrier layer made of a thin film mainly composed of a single-layer silicon compound. In particular, as a multilayer gas barrier thin film mainly composed of silicon oxide, the xn value of each of the first silicon oxide layer SiO _x1 C _{y1 to} the n-th silicon oxide layer SiO _xn C _yn laminated on the inner surface of the plastic container, A gas barrier plastic container having a multilayer gas barrier thin film mainly composed of silicon oxide formed by discontinuously decreasing x1>x2>x3>...> xn has a very high water vapor barrier property. Have Further, according to the present invention, in the conventional gas barrier thin film mainly composed of a single layer of silicon oxide, in order to introduce an excessive material gas into the reaction layer in order to obtain a predetermined film thickness, Deformation and coloring occur, the oxidation reaction of the material gas does not proceed sufficiently, and the material gas such as an organic compound does not become inorganic, so that the problem that sufficient gas barrier properties cannot be obtained is solved.

  Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view of a horizontal low temperature plasma chemical vapor deposition apparatus for carrying out the method for producing a gas barrier plastic container of the present invention. FIG. 2 shows a gas barrier plastic container of the present invention. FIG. 3 is a schematic sectional view of a multilayer gas barrier thin film mainly composed of silicon oxide formed on the inner surface of a plastic container by the method of the present invention described later.

  The horizontal low temperature plasma chemical vapor deposition apparatus shown in FIG. 1 includes a base 10 and an external electrode 12 attached to the base 10 via an insulating plate 11. The external electrode 12 serves as a vacuum chamber for forming a gas barrier thin film, and has a space 20 having a similar shape slightly larger than the plastic container body 1 for accommodating the plastic container body 20. . The external electrode 12 includes a main body 12a and a lid 12b. The lid 12b is detachably attached to the main body and functions to seal the main body 12a. A high frequency power supply 14 is connected to the external electrode 12 via a matching unit 13. The external power source 12 is provided with an exhaust pipe 15 that communicates with the space 20. The exhaust pipe 1 is connected to a vacuum pump (not shown), and the air inside the plastic container body 1 disposed in the space 20 of the external electrode 12 by the vacuum pump is exhausted in the direction indicated by the arrow P1. 15 is configured to be exhausted.

  Opposite to the external electrode 12, the internal electrode 16 is disposed so as to be positioned at the center of the space portion of the external electrode. The internal electrode 16 has an outer shape that can be inserted from the mouth portion 1 a of the plastic container body 1 attached in the space 20 of the external electrode 12 and corresponds to the internal shape of the plastic container body 1. The distance between the internal electrode 16 and the external electrode 12 is preferably maintained at almost equal intervals at any position in order to uniformly form the gas barrier thin film on the entire inner surface of the plastic container body 1.

  The internal electrode 16 is connected to a raw material gas supply pipe 17, and through this raw material gas supply pipe 17, as shown by an arrow P, to the internal electrode 16, vapor deposition monomer gas such as an organosilicon compound, oxygen gas, inert gas, The material gas composition for vapor deposition prepared using the other is supplied. Further, the internal electrode 16 is provided with a plurality of source gas blowouts 16a, and the source gas composition for vapor deposition is blown out from the source gas supply holes 16a into the internal space of the plastic container body 1. The internal electrode 16 is grounded via the source gas supply pipe 17.

  Next, the manufacturing method of the gas barrier plastic container of this invention using the horizontal type low temperature plasma chemical vapor deposition apparatus shown in FIG. 1 is demonstrated. First, the lid body 12b of the external electrode 12 is removed from the main body portion 12, the plastic container body 1 is inserted into the space portion 20, and then the lid body 12b is attached to the main body portion 12a to seal the space portion 20.

  Next, the space 20 and the inside of the plastic container main body 1 are exhausted by the vacuum pump through the exhaust pipe 15 until plasma can be generated, and the degree of vacuum is increased. Next, an inert gas such as argon (Ar) or helium (He) is supplied into the plastic container body 1 through the source gas supply pipe 17. At the same time, a high frequency voltage is applied between the external electrode 12 and the internal electrode 16 to generate plasma. The inert gas plasmified by the plasma is blown out from the raw material gas blowing holes 16a into the internal space of the plastic container body 1, thereby performing plasma etching as a pretreatment on the entire inner surface of the plastic container body 1, and thereby the plastic container body. Fine irregularities are formed on the entire inner surface of 1 by plasma treatment to form a plasma-treated surface having a large surface area.

  Next, the degree of vacuum in the space portion 20 is increased by evacuating the space portion 20 again to a pressure at which plasma can be generated through the exhaust pipe 15 by the vacuum pump. Next, a raw material gas composition for vapor deposition prepared using a monomer gas for vapor deposition such as an organosilicon compound, oxygen gas, inert gas, and the like is supplied into the plastic container body 1 through a raw material gas supply pipe 17. At the same time, a high frequency voltage is applied between the external electrode 12 and the internal electrode 16 to generate plasma, and the plasma-deposited raw material gas composition is blown into the plastic container body 1 from the raw material blowing holes 16a. A gas barrier thin film mainly composed of first silicon oxide is formed on the inner surface of the plastic container body 1.

  After the formation of the gas barrier thin film mainly composed of the first silicon oxide, the space 20 of the external electrode 12 and the inside of the plastic container body 1 are evacuated again by a vacuum pump. Then, the flow rate of the source gas for vapor deposition, such as an organosilicon compound, the flow rate of oxygen gas, the degree of vacuum, and the discharge time are the same as in the formation of the gas barrier thin film mainly composed of the first silicon oxide, except that the plasma discharge output is Prepared by using a monomer gas for vapor deposition such as an organosilicon compound, oxygen gas, inert gas, etc. in the plastic container body 1 lower than when forming a gas barrier thin film mainly composed of the first silicon oxide. The vapor deposition raw material gas composition is supplied, and at the same time, a high frequency voltage lower than the high frequency voltage at the time of forming the gas barrier thin film mainly composed of the first silicon oxide is applied between the external electrode 12 and the internal electrode 16. Then, plasma is generated, and the above-described vapor deposition source gas composition is blown into the plastic container main body 1 from the raw material blowing holes 16a to mainly contain the first silicon oxide. A second silicon oxide to form a gas barrier thin film mainly on gas barrier thin film.

  Next, after forming the gas barrier thin film mainly composed of the second silicon oxide, the space 20 of the external electrode 12 and the inside of the plastic container main body 1 are evacuated again by a vacuum pump. Then, the flow rate of the source gas for vapor deposition such as an organic compound, the flow rate of oxygen gas, the degree of vacuum, and the discharge time are the same as in the formation of the gas barrier thin film mainly composed of the second silicon oxide, except that the plasma discharge output is 2. Source gas composition for vapor deposition prepared by using a monomer gas for vapor deposition such as an organic compound, oxygen gas, etc. in the plastic container body 1 at a lower temperature than the formation of the gas barrier thin film mainly composed of silicon oxide. In addition, a plasma discharge voltage is applied between the external electrode 12 and the internal electrode 16 to generate a plasma between the external electrode 12 and the internal electrode 16 by applying a plasma discharge voltage lower than that in the formation of the gas barrier thin film mainly composed of the second silicon oxide. The vaporized raw material gas composition for vapor deposition is blown out from the raw material blowing hole 16a into the plastic container main body 1 to form a third on the gas barrier thin film mainly composed of the second silicon oxide. Forming a gas barrier thin film mainly composed of silicon hydride.

  Thereafter, in the same manner, the flow rate of the vapor deposition monomer gas such as an organic compound, the flow rate of the oxygen gas, the degree of vacuum, and the discharge time are not changed, but the plasma discharge output is sequentially decreased, and the third, fourth,... A gas barrier thin film mainly composed of nth silicon oxide is formed, and a gas barrier thin film 2a mainly composed of first silicon oxide is formed on the inner surface of the plastic container main body 1 as schematically shown in FIG. Gas barrier thin film mainly composed of silicon: a multi-layer gas barrier thin film 2 composed of a multi-layer gas barrier thin film 2n mainly composed of silicon oxide composed mainly of the uppermost nth silicon oxide is formed. After the elapse of time sufficient for forming a gas barrier thin film mainly composed of n silicon oxide, the supply of the raw material gas composition for vapor deposition from the raw material gas supply pipe 17 is stopped, and then in the space 20 of the external electrode 12 Introducing the atmosphere, Figure 2 The multilayer gas barrier film 2 made mainly of silicon oxide as shown formed on the inner surface of the plastic container, it is possible to obtain a gas barrier plastic container A of the present invention.

When the gas barrier thin film mainly composed of silicon oxide constituting the multilayer gas barrier thin film mainly composed of silicon oxide is formed as described above, the flow rate of the monomer gas for vapor deposition such as an organosilicon compound, the oxygen gas The flow rate, the degree of vacuum, and the discharge time are kept constant, the plasma discharge output is sequentially decreased, and the degree of oxidation of the gas barrier thin film mainly composed of silicon oxide is sequentially decreased, thereby stacking on the inner surface of the plastic container. The xn value of each of the first silicon oxide layer SiO _x1 C _{y1 to} the nth silicon oxide layer SiO _xn C _yn is laminated by decreasing discontinuously as x1>x2>x3>. A multilayer gas barrier thin film mainly composed of silicon oxide can be formed. This multi-layer gas barrier thin film mainly composed of silicon oxide imparts an extremely high oxygen barrier property to the inner surface of the plastic container body 1 and is 1 to 50 g / m ² · day (40 ° C./100% RH). It has a water vapor transmission coefficient and an oxygen transmission coefficient of 0.1 to 10 cc · nm / m ² · day · atm (23 ° C./90% RH).

In the above manufacturing method, the plasma discharge output is gradually decreased from the first layer to the uppermost layer during the formation of each layer, and the introduction amount of the organosilicon compound and the introduction amount of oxygen gas into the reaction layer are reduced from the first layer to the highest layer. The first silicon oxide layer SiO _x1 C _{y1 to} the n th layer to be laminated on the inner surface of the plastic container is reduced stepwise over the upper layer and the degree of oxidation of the gas barrier thin film mainly composed of silicon oxide is sequentially reduced. The xn value of each layer of the silicon oxide layer SiO _xn C _yn is reduced discontinuously with x1>x2>x3>. be able to.

  In addition, vapor deposition monomer gas such as organic silicon compound as a raw material is volatilized using a raw material volatilization device, etc., and is mixed with oxygen gas, inert gas, etc. supplied from other gas supply devices. A gas is prepared, and this source gas composition for vapor deposition is introduced into the space 20 of the external electrode 12 through the source gas supply pipe 17. In this case, the content of the vapor deposition monomer gas such as an organosilicon compound in the vapor deposition raw material gas composition is about 1 to 40%, the oxygen gas content is about 10 to 70%, and the inert gas content is A range of about 10 to 60% is desirable. For example, it is desirable that the vapor deposition amount of the organic silicon compound, etc. The mixing ratio of monomer gas: oxygen gas: inert gas is about 1: 6: 5 to 1:17:14. In this case, an inert gas is not necessarily required, and vapor deposition may be performed using a reaction gas composed of two kinds of organic source gas and oxygen gas. The flow ratio of the organosilicon compound and oxygen gas is 1: It is desirable to be in the range of 5 to 1:20. In this case, the amount of gas introduced is desirably 1 to 50 sccm for the organic silicon compound, 5 to 500 sccm for the oxygen gas, more preferably 2 to 6 sccm for the organic silicon compound, and 20 to 100 sccm for the oxygen gas.

  Further, as described above, since a predetermined voltage is applied from the power source between the external electrode 12 and the internal electrode 16, glow discharge plasma is generated in the vicinity of the source gas blowing hole 16a of the internal electrode 16. This glow discharge plasma is derived from one or more gas components in the raw material gas composition for vapor deposition, and the glow discharge plasma causes an inorganic oxide such as silicon oxide to be deposited on the entire inner surface of the plasma vessel body 1. A main gas barrier thin film can be formed. At this time, the degree of vacuum in the hollow portion 20 of the external electrode 12 is desirably adjusted to about 1 to 100 Pa, preferably about 10 to 70 Pa. Moreover, as processing time which forms a vapor deposition film, it is desirable to adjust to 1 to 300 second, Preferably it is about 5 to 30 second.

A gas barrier thin film mainly composed of inorganic oxides such as silicon oxide is formed on the entire inner surface of the plastic container body in the form of a thin film in the form of SiO _xn C _yn while oxidizing the plasma source gas with oxygen gas. Is done. This gas barrier thin film mainly composed of an inorganic oxide such as silicon oxide is a dense, flexible continuous layer having few gaps. Therefore, the barrier property of the gas barrier thin film mainly composed of an inorganic oxide such as silicon oxide is much higher than that of a gas barrier thin film formed by a conventional vacuum deposition method, and a thin film thickness is sufficient. Barrier properties can be obtained. Further, unlike the conventional SiO _x composed of silicon and oxygen, the film contains a carbon component, so that a flexible film quality can be obtained.

Further, in the present invention, the inner surface of the plastic container body 1 is cleaned by the SiO _x plasma, and polar groups, free radicals, etc. are generated on the inner surface of the plastic container body 1, so that the plastic container body of the gas barrier thin film Adhesion with the inner surface of 1 is high. Furthermore, as described above, the degree of vacuum in the space 20 of the external electrode 12 when the gas barrier thin film mainly composed of an inorganic oxide such as silicon oxide is formed is adjusted to about 1 to 100 Pa, preferably about 10 to 70 Pa. Therefore, the plasticity is low because the degree of vacuum is lower than the degree of vacuum (0.1 Pa or less) when forming a gas barrier thin film mainly composed of inorganic oxide of silicon oxide Muto by the conventional vacuum deposition method. The vacuum setting time at the time of exchanging the container body can be shortened and the degree of vacuum can be easily stabilized, so that the film forming process is stabilized.

In the present invention, the gas barrier thin film mainly composed of an inorganic oxide such as silicon oxide formed using a vapor deposition monomer gas such as an organosilicon compound, chemically reacts with the vapor deposition monomer gas such as an organosilicon compound and oxygen gas, The reaction product adheres to the surface of the inner surface of the plastic container body 1 to form a dense and flexible thin film. This thin film is a thin film mainly composed of silicon oxide represented by the general formula SiO _X C _Y (where 1.5 <X ≦ 2.2, 0.1 ≦ Y ≦ 0.5). The value of x varies depending on the molar ratio of vapor deposition monomer gas: oxygen gas, plasma energy, etc. In general, the smaller the value of x, the smaller the gas permeability, and the film itself becomes yellowish. Transparency deteriorates. Therefore, it is desirable that x is greater than 1.5.

The gas barrier thin film mainly composed of silicon oxide is a gas barrier thin film mainly composed of silicon oxide in which at least silicon atoms, oxygen atoms, and carbon atoms are chemically bonded. More specifically, this gas barrier thin film is mainly composed of silicon oxide, and further contains at least one compound of one kind of carbon, hydrogen, silicon or oxygen, or two or more kinds of elements. . For example, as a gas barrier thin film mainly composed of silicon oxide, a compound having a C—H bond, a compound having a Si—H bond, or a graphite, diamond, or fullerene-like carbon, and further organic silicon as a raw material Some include compounds and their derivatives. Specific examples include hydrocarbons having a CH ₃ site, hydrosilica such as SiH ₃ silyl, SiH ₂ silylene, and hydroxyl derivatives such as SiH ₂ OH silanol. Also, by changing the conditions of the vapor deposition process, the type, content, etc. of the compound contained in the gas barrier thin film mainly composed of silicon oxide can be changed. Thus, the content of the compound other than silicon oxide contained in the gas barrier thin film mainly composed of silicon oxide is about 0.1 to 50%, preferably about 5 to 30%. If the content of the compound other than silicon oxide is less than 0.1%, the gas barrier thin film mainly composed of silicon oxide has insufficient impact resistance, spreadability, flexibility, etc., and scratches, cracks, etc. due to bending or the like. Etc. are likely to occur, and it becomes difficult to stably maintain a high gas barrier property. On the other hand, if it exceeds 50%, the gas barrier property is lowered, which is not preferable. Therefore, the Y value of silicon oxide represented by the general formula SiO _x C _y is preferably in the range of 0.01 to 0.5, more preferably 0.05 to 0.3.

  Further, in the present invention, the gas barrier thin film mainly composed of silicon oxide has at least silicon atoms, oxygen atoms and carbon atoms chemically bonded, and further has a carbon atom weight of 100 to 190%, preferably 130 to 100 parts per 100 parts of silicon atoms. Containing 180%, and following shrinkage and expansion from 3% of the surface area shrinkage immediately after molding the plastic container body to 5% of the plastic container body just after filling the contents in the plastic container body It is possible.

  Thus, in the present invention, for a multilayer gas barrier thin film mainly composed of silicon oxide, for example, an X-ray photoelectron spectrometer (Xray Photoelectron Spectroscopy, XPS), a secondary ion mass spectrometer (Secondary Ion Mass Spectroscopy, SIMS) The physical properties can be confirmed by performing elemental analysis of a gas barrier thin film mainly composed of silicon oxide using a method of analyzing by performing ion etching in the depth direction using a surface analyzer such as the above.

  In the present invention, the thickness of the multi-layer gas barrier thin film mainly composed of silicon oxide is 5 to 400 nm, preferably about 20 to 100 nm. If the film thickness exceeds 100 nm, and more than 400 nm, it is not preferable because the film is likely to be cracked. On the other hand, if it is smaller than 20 nm, and if it is smaller than 5 nm, it is not preferable because it becomes extremely difficult to achieve the effect of barrier properties.

  In the present invention, the plasma discharge output can usually be freely selected in the range of 100 to 800 W, but 150 to 600 W is a desirable range. If it is 100 W or less, there is a problem that the organic silicon compound is not sufficiently converted to an inorganic substance and gas barrier properties cannot be imparted, and an unreacted organosilicon compound remains in the thin film. Above 800W, conversion to inorganic materials can be accelerated and a highly gas barrier thin film can be formed. However, because the plasma discharge output is high, the surface temperature of the internal electrode becomes excessively high, which causes deformation of the container. There is a problem that is caused. In addition, due to excessive plasma discharge output, the formed gas barrier thin film mainly composed of silicon oxide is likely to be etched, which causes a problem that pinholes are generated and the gas barrier property is impaired.

  In the present invention, as the monomer gas for vapor deposition, for example, 1.1.3.3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethylsilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, Uses dimethylsilane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane and other organosilicon compounds be able to. Among them, 1.1.3.3-tetramethyldisiloxane and hexamethyldisiloxane are particularly preferable materials from the viewpoints of easy handling and characteristics of the formed continuous film. Moreover, argon gas, helium gas, etc. can be applied as the inert gas. Furthermore, as a carbon atom supply source in a vapor deposition source gas composition prepared using vapor deposition monomer gas such as an organosilicon compound, oxygen gas, inert gas, etc., methane gas, propane gas, carbon dioxide, acetylene gas, etc. The gas can also be added.

  In the present invention, as a plastic container body, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyacrylic intent, polymethacrylic resin, polyacrylonitrile resin, polystyrene resin, styrene-acrylonitrile copolymer, styrene- One or more types of butadiene-acrylonitrile copolymer, polycarbonate resin, polyester resin or recycled polyester resin, polyamide resin, polyacetal resin, and other resins are used as a molding resin material, Cups, bottles, bottles and other forms of molding containers formed by molding, injection molding, blow molding, cast molding, thermoforming and other molding methods can be applied. Thus, in the present invention, as the plastic container body, liquid drinks, seasonings, and sake. A blow molded container made of a polyester resin suitable for filling and packaging beer or other liquid or a polyolefin resin such as polyethylene or polypropylene is particularly desirable.

  In the present invention, the gas barrier thin film mainly composed of silicon oxide has 2 to 10 layers, preferably 3 to 5 layers. With one layer, it is difficult to impart a high gas barrier property to a plastic container, and when there are multiple layers than ten layers, the gas barrier property is excellent, but the process cycle time is long.

  Next, the present invention will be described in detail with reference to examples and comparative examples.

As a plastic container body, a polyethylene terephthalate (PET) blow molded bottle having a capacity of 220 ml was prepared. The plastic container body has an average wall thickness of 550 μm, an effective gas permeation area of 230 cm ² , an oxygen permeability of 0.080 cc / pg / day (0.21 atm), and a water vapor permeability of 0.0130 g / kg / kg. It was a day.

  A plastic body was attached to the space 20 of the external electrode 12 of the horizontal low-temperature plasma chemical vapor deposition apparatus shown in FIG. 1, and the space 20 was sealed with a lid 12b. Next, the pressure inside the plastic container body was lowered to 30 Pa.

  A high frequency voltage of 13.56 MHz and 400 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material composition consisting of 2 sccm of hexamethyldisiloxane and 20 sccm of oxygen gas was maintained while maintaining a gas flow rate of 22 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. The gas barrier thin film mainly composed of the first silicon oxide was formed on the inner surface of the plastic container body while generating plasma of the source gas for 15 seconds. The thickness of this gas barrier thin film was 15 nm.

  Again, the internal pressure of the plastic container body was lowered to a vacuum degree of 30 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 350 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 2 sccm of hexamethyldisiloxane and 20 sccm of oxygen gas was maintained at a gas flow rate of 22 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating plasma of the source gas, the gas barrier thin film mainly composed of the second silicon oxide was formed by holding for 15 seconds. The total film thickness of the first gas barrier thin film and the second gas barrier thin film was 22 nm.

  Again, the internal pressure of the plastic container body was lowered to a vacuum degree of 30 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 300 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 2 sccm of hexamethyldisiloxane and 20 sccm of oxygen gas was maintained at a gas flow rate of 22 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating the plasma of the source gas, it is held for 15 seconds to form a gas barrier thin film mainly composed of the third silicon oxide, and the first gas barrier thin film, the second gas barrier thin film, and the third gas barrier property. A thin film laminate was obtained. The total film thickness of this laminate was 30 nm.

  The same plastic container body as in Example 1 was used. This plastic container main body was attached to the space part 20 of the external electrode 12 of the horizontal low-temperature plasma chemical vapor deposition apparatus shown in FIG. 3, and the space part 20 was sealed with the lid 12b. Next, the pressure inside the plastic container body was lowered to 30 Pa.

  A high frequency voltage of 13.56 MHz and 500 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material composition consisting of 3 sccm of hexamethyldisiloxane and 30 sccm of oxygen gas was maintained while maintaining a gas flow rate of 33 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. The gas barrier thin film mainly composed of the first silicon oxide was formed on the inner surface of the plastic container body while generating plasma of the source gas for 15 seconds. The thickness of this gas barrier thin film was 20 nm.

  Again, the internal pressure of the plastic container body was lowered to a vacuum degree of 30 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 400 W is applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 2 sccm of hexamethyldisiloxane and 20 sccm of oxygen gas is maintained at a gas flow rate of 22 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating plasma of the source gas, the gas barrier thin film mainly composed of the second silicon oxide was formed by holding for 15 seconds. The total film thickness of the first gas barrier thin film and the second gas barrier thin film was 30 nm.

  Again, the internal pressure of the plastic container body was lowered to a vacuum degree of 30 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 300 W is applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 1 sccm of hexamethyldisiloxane and 10 sccm of oxygen gas is maintained at a gas flow rate of 11 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating the plasma of the source gas, it is held for 15 seconds to form a gas barrier thin film mainly composed of the third silicon oxide, and the first gas barrier thin film, the second gas barrier thin film, and the third gas barrier property. A thin film laminate was obtained. The total film thickness of this laminate was 42 nm.

  The same plastic container body as in Example 1 was used. This plastic container main body was attached to the space part 20 of the external electrode 12 of the horizontal low-temperature plasma chemical vapor deposition apparatus shown in FIG. 3, and the space part 20 was sealed with the lid 12b. Next, the pressure inside the plastic container body was lowered to 20 Pa.

  A high frequency voltage of 13.56 MHz and 550 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material composition consisting of 4 sccm of hexamethyldisiloxane and 50 sccm of oxygen gas was maintained while maintaining a gas flow rate of 54 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. And it hold | maintained for 10 second, generating the plasma of source gas, and formed the gas barrier thin film which has the 1st silicon oxide as a main body on the inner surface of the plastic container main body. The thickness of this gas barrier thin film was 15 nm.

  The internal pressure of the plastic container body was again lowered to a vacuum degree of 20 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 300 W was applied between the internal electrode 167 and the external electrode 12, and then a raw material gas composition consisting of 3 sccm of hexamethyldisiloxane and 40 sccm of oxygen gas was applied to the inside while maintaining the gas flow rate at 43 ml / min. Plasma was supplied to the inside of the plastic container body from the blowing hole 16a of the electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating the plasma of the raw material gas, the gas barrier thin film mainly composed of the second silicon oxide was formed by holding for 10 seconds. The total film thickness of the first gas barrier thin film and the second gas barrier thin film was 25 nm.

  The internal pressure of the plastic container body was again lowered to a vacuum degree of 20 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 200 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 2 sccm of hexamethyldisiloxane and 30 sccm of oxygen gas was maintained at a gas flow rate of 32 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating the plasma of the source gas, the gas barrier thin film mainly composed of the third silicon oxide was formed by holding for 10 seconds. The total film thickness of the first gas barrier thin film, the second gas barrier thin film, and the third gas barrier thin film was 32 nm.

  The internal pressure of the plastic container body was again lowered to a vacuum degree of 20 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 180 W is applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 1 sccm of hexamethyldisiloxane and 15 sccm of oxygen gas is maintained at a gas flow rate of 16 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating the plasma of the source gas, it is held for 10 seconds to form a gas barrier thin film mainly composed of the fourth silicon oxide, the first gas barrier thin film, the second gas barrier thin film, and the third gas barrier property. A laminate of the thin film and the fourth gas barrier thin film was obtained. The total film thickness of this laminate was 48 nm.

[Comparative Example 1]
The same plastic container body as in Example 1 was used. This plastic container main body was attached to the space part 20 of the external electrode 12 of the horizontal low-temperature plasma chemical vapor deposition apparatus shown in FIG. 3, and the space part 20 was sealed with the lid 12b. Next, the pressure inside the plastic container body was lowered to 30 Pa.

  A high frequency voltage of 13.56 MHz and 200 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material composition consisting of 3 sccm of hexamethyldisiloxane and 30 sccm of oxygen gas was maintained while maintaining a gas flow rate of 22 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. The gas barrier thin film mainly composed of silicon oxide was formed on the inner surface of the plastic container main body while maintaining the plasma of the source gas for 45 seconds. The thickness of this gas barrier thin film was 60 nm.

[Comparative Example 2]
In the same manner as in Comparative Example 1, except that the applied voltage was changed to 400 W, and a gas barrier thin film mainly composed of silicon oxide was formed on the inner surface of the plastic container body. The thickness of this gas barrier thin film was 70 nm.

[Comparative Example 3]
The same plastic container body as in Example 1 was used. This plastic container main body was attached to the space part 20 of the external electrode 12 of the horizontal low-temperature plasma chemical vapor deposition apparatus shown in FIG. 3, and the space part 20 was sealed with the lid 12b. Next, the pressure inside the plastic container body was lowered to 30 Pa.

  A high frequency voltage of 13.56 MHz and 200 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material composition consisting of 2 sccm of hexamethyldisiloxane and 20 sccm of oxygen gas was maintained while maintaining a gas flow rate of 22 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. The gas barrier thin film mainly composed of the first silicon oxide was formed on the inner surface of the plastic container body while generating plasma of the source gas for 15 seconds. The thickness of this gas barrier thin film was 15 nm.

  Again, the internal pressure of the plastic container body was lowered to a vacuum degree of 30 Pa by a vacuum pump.

  A gas barrier thin film mainly composed of the second silicon oxide was formed on the gas barrier thin film mainly composed of the first silicon oxide under the same conditions as the production conditions of the first gas barrier thin film. The total film thickness of the gas barrier thin film mainly composed of the first silicon oxide and the gas barrier thin film mainly composed of the second silicon oxide was 30 nm.

[Comparative Example 4]
The same plastic container body as in Example 1 was used. This plastic container main body was attached to the space part 20 of the external electrode 12 of the horizontal low-temperature plasma chemical vapor deposition apparatus shown in FIG. 3, and the space part 20 was sealed with the lid 12b. Next, the pressure inside the plastic container body was lowered to 30 Pa.

  A high frequency voltage of 13.56 MHz and 400 W was applied between the internal electrode 16 and the external electrode 12, and then a raw material composition consisting of 1 sccm of hexamethyldisiloxane and 10 sccm of oxygen gas was maintained while maintaining a gas flow rate of 11 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. The gas barrier thin film mainly composed of the first silicon oxide was formed on the inner surface of the plastic container body while generating plasma of the source gas for 15 seconds. The thickness of this gas barrier thin film was 10 nm.

  Again, the internal pressure of the plastic container body was lowered to a vacuum degree of 30 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 400 W is applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 2 sccm of hexamethyldisiloxane and 20 sccm of oxygen gas is maintained at a gas flow rate of 22 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating plasma of the source gas, the gas barrier thin film mainly composed of the second silicon oxide was formed by holding for 15 seconds. The total film thickness of the first gas barrier thin film and the second gas barrier thin film was 22 nm.

  Again, the internal pressure of the plastic container body was lowered to a vacuum degree of 30 Pa by a vacuum pump.

  A high frequency voltage of 13.56 MHz and 400 W is applied between the internal electrode 16 and the external electrode 12, and then a raw material gas composition composed of 3 sccm of hexamethyldisiloxane and 30 sccm of oxygen gas is maintained at a gas flow rate of 33 ml / min. Plasma was supplied to the inside of the plastic container body from the blowout hole 16a of the internal electrode 16 to generate a raw material gas plasma inside the plastic container body. Then, while generating the plasma of the source gas, it is held for 15 seconds to form a gas barrier thin film mainly composed of the third silicon oxide, and the first gas barrier thin film, the second gas barrier thin film, and the third gas barrier property. A thin film laminate was obtained. The total film thickness of this laminate was 38 nm.

  The oxygen permeability was measured for the plastic container body produced in Examples 1 to 3 and Comparative Examples 1 to 4 and formed with a gas barrier thin film. The measurement of oxygen permeability was carried out using a measuring instrument manufactured by MOCON (model name, OXTRAN, 2/20) under the conditions of a temperature of 23 ° C. and a humidity of 90% Rh.

The measurement of water vapor permeability was performed using a measuring instrument manufactured by MOCON (model name, Permtran, C-200) under the conditions of a temperature of 40 ° C. and a humidity of 90% RH. Then, the water vapor permeability coefficient Hc of the multilayer gas barrier thin film was calculated based on the obtained water vapor permeability value. In the equation, Yb is the water vapor permeability (g / pk · day) of the blank plastic container body, Ys is the oxygen permeability (cc / pk · day) of the plastic container body formed with the multilayer gas barrier thin film, A Represents the surface area (m ² ) of the plastic container body, and t represents a single-layer gas barrier thin film and a multi-layer gas barrier thin film (mm). The thickness of the multi-layer gas barrier thin film is measured using a Rigaku X-ray fluorescence spectrometer (RIX2000), and the film thickness of the gas barrier thin film mainly composed of silicon oxide is based on the known 40 nm silicon oxide amount. Obtained by conversion.

[Equation 1]
Hc = t × 1 / (Xs / A−Xb / A)

  Table 1 shows the permeability and permeability of oxygen and water vapor.

  The degree of oxidation of the gas barrier thin film was measured by performing surface analysis based on ESCA (Electron Spectroscopy For Chemical Analysis) method. Specifically, the measurement was performed using an X-ray photoelectron analyzer (model name, ESCA850 type) manufactured by Shimadzu Corporation. The results are shown in Table 2.

As shown in Table 1, Examples 1 to 3 have an extremely low water vapor transmission coefficient of 2.2 to 2.4 g · nm / m ² · day · atm, and oxygen permeability of 0.0013 to 0.0022 cc. /Pkg·0.21 atm · day was extremely low, and the gas barrier property was found to be extremely high. On the other hand, in Comparative Examples 1 to 4, the water vapor transmission coefficient was as high as 57 to 203 g · nm / m ² · day · atm, and excellent water vapor barrier properties were not seen as in Examples 1 to 3.

  Moreover, the oxidation degree of the 1st layer which comprises the multilayer gas-barrier thin film of Examples 1-3 is high, it is 1.82-1.89, and the oxidation degree of the uppermost layer is also high 1.60-1.65. . In contrast, Comparative Examples 1 and 2 have low oxidation degrees of 1.34 and 1.38. In Comparative Example 3, the oxidation degree of the first layer and the second layer is low. In Comparative Example 4, the oxidation degree of the first layer is relatively high at 1.65, but the oxidation degree of each layer gradually decreases as it goes to the uppermost layer, and the oxidation degree of the uppermost layer becomes 1.44. ing. Thus, it was proved that each layer of the multilayer gas gas barrier thin film of the present invention has a unit oxidation degree as compared with 4 in Comparative Example 1.

  The gas barrier plastic container of the present invention can be effectively used as a packaging container for contents such as liquid beverages, seasonings, liquor, beer and other liquids.

1 is a schematic view of a horizontal low-temperature plasma chemical vapor deposition apparatus for producing a gas barrier plastic container of the present invention. 1 is a schematic view of a gas barrier plastic container of the present invention. 1 is a schematic view of a multilayer gas barrier thin film mainly composed of silicon oxide.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plastic container main body 1a Mouth part of plastic container main body 2 Gas barrier thin film mainly made of silicon oxide 10 Base 11 Insulating plate 12 External electrode 12a External electrode main body 12b External electrode cover 13 Matching device 14 High frequency power supply 15 Exhaust pipe 16 Internal electrode 16a Raw material gas supply pipe 17 Raw material gas supply pipe 20 External power supply space P1 arrow P2 arrow

Claims (8)

A gas barrier thin film mainly composed of a plurality of layers of silicon oxide formed on the inner surface of the plastic container body by plasma chemical vapor deposition,
In addition, the gas barrier thin film mainly composed of a plurality of layers of silicon oxide described above gradually reduces the plasma discharge output from the first layer to the uppermost layer when forming each layer, and introduces the organosilicon compound into the reaction vessel. By gradually reducing the amount and the amount of oxygen gas introduced from the first layer to the top layer,
A gas barrier plastic container comprising a multilayer gas barrier thin film mainly composed of silicon oxide in which the oxidation degree of each layer is sequentially decreased from the first layer to the uppermost layer. In the method for producing a gas barrier plastic container comprising a multilayer gas barrier thin film mainly composed of silicon oxide SiOxnCyn on the inner surface of the plastic container main body,
On the inner surface of the plastic container body , the plasma discharge output is gradually reduced from the first layer to the uppermost layer when forming each layer, and the introduction amount of the organosilicon compound and the introduction amount of oxygen gas into the reaction vessel are reduced to the first layer. Gradually decrease from top to bottom
Using a source gas containing an organosilicon compound to form a multi-layer gas barrier thin film consisting mainly of multiple layers of silicon oxide and successively reducing the degree of oxidation of each layer by plasma enhanced chemical vapor deposition A method for producing a gas barrier plastic container. 3. The method for producing a gas barrier plastic container according to claim 2, wherein the introduction amount of the organosilicon compound is 6 sccm or less and the introduction amount of the oxygen gas is 100 sccm or less. The method for producing a gas barrier plastic container according to any one of claims 2 to 3 , wherein a polyester resin blow molded container is used as the plastic container body. The method for producing a gas-barrier plastic container according to any one of claims 2 to 3 , wherein a polyolefin resin blow-molded container is used as the plastic container body. The method for producing a gas barrier plastic container according to any one of claims 2 to 5 , wherein a plasma discharge output range at the time of forming each layer is 150 W to 600 W. The method for producing a gas barrier plastic container according to any one of claims 2 to 6 , wherein an organic silicon compound to oxygen gas flow ratio is in a range of 1: 5 to 1:20. The method for producing a gas barrier plastic container according to any one of claims 2 to 7, wherein the total thickness of the organosilicon compound is in the range of 20 to 100 nm.

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