JP2001158415A - Plastic bottle for atmospheric low temperature plasma treatment and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and inexpensive thermoplastic bottle of superior recycle properties and also oxygen and CO2 barrier properties for which an existing manufacturing equipment can be utilized and the remarkable increase of the manufacturing rate can be realized and also provide a manufacturing method thereof. SOLUTION: A plastic bottle of oxygen and CO2 barrier properties having a surface layer, which is formed by using an atmospheric low temperature plasma and applying the organic and/or inorganic film coating or the surface treatment at least on one of the outer surface and the inner surface of the plastic bottle, is provided and also a manufacturing method thereof is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to oxygen and carbon dioxide for alcoholic beverages such as beer, soft drinks and the like, which need to be free from oxidation from the aspect of quality as a content and need not escape carbon dioxide gas from the container wall. Plastic bottles for beverages having gas barrier properties, more particularly, an organic and / or inorganic thin film coating on at least one of the outer surface and inner surface as an oxygen and carbonic acid barrier layer, or a surface formed by inert gas plasma or reactive gas plasma The present invention relates to an inexpensive and lightweight thermoplastic bottle excellent in impact resistance and recyclability, in which a surface barrier layer is formed by a treatment, and a method for producing the same.

[0002]

2. Description of the Related Art Beer has been popular in Europe since ancient times as a beverage for people, and in recent years has been consumed in large quantities as alcoholic beverages for common people worldwide. In recent years, beer has been brewed in large quantities in factories, filled in small containers, transported to consuming areas, stored, and sold. Such beer not only requires retention of aroma during transportation and storage, but also is easily oxidizable and contains carbon dioxide gas. Was used.

[0003] Aluminum cans have the advantages of being lightweight, being excellent in recyclability, gas barrier properties, impact resistance, light-shielding properties, and being beautiful, and having an easily oxidizable or non-oxidizable content. It is considered to be a very ideal material for packaging materials, and recently, its use has been increasing to occupy the mainstream as a container for beer. On the other hand, raw materials are expensive, manufacturing equipment such as aluminum can manufacturing equipment, contents filling equipment, etc. requires large, high-performance equipment, and requires a very large investment amount,
It can only deal with small varieties and mass production.
In addition, aluminum requires corrosion treatment, the product price is high, it is difficult to increase the size of the container, and the visibility of the contents in the food market is one of the major product concepts. Is mainly used for small containers of 1 liter or less that cannot be resealed.

[0004] Glass bottles that have been used in the largest quantities in the past have excellent recyclability, gas barrier properties, corrosion resistance, and resealability, can be used in a wide variety of small-quantity production, and are relatively inexpensive to produce. Although there are advantages that can be achieved, it has the serious disadvantage that the product weight is heavy and the impact resistance is extremely weak compared to aluminum cans and plastic bottles, and the market is gradually replacing aluminum cans etc. Although it seems that measures such as thinning the wall of the bottle to reduce its weight are being taken as a countermeasure, its effect is unclear because there is a limit.

[0005] Plastic containers are transparent and lightweight,
It is an excellent packaging material that has excellent impact resistance, corrosion resistance, low product price, small capital investment, and can be used for containers of high-mix low-volume production.
Glass bottles have no problem at all and have low gas barrier properties.They dislike oxidation in terms of quality, and contents that dislike escape of carbon dioxide gas.For example, as a container for beer, oxygen gas permeability, carbon dioxide gas permeability, etc. It has a serious drawback of low gas barrier properties. As a measure for improving the gas barrier properties of such a plastic container, a number of multilayer plastic bottles having improved gas barrier properties by laminating a gas barrier resin layer together with a structural material resin layer have been proposed.

As a conventional method for producing a multilayer plastic bottle, polyethylene terephthalate (hereinafter referred to as “PET”) is used.
That. ) Or a thermoplastic (structural material resin) such as polypropylene (hereinafter referred to as “PP”) and a saponified product of ethylene-vinyl acetate copolymer (ethylene-vinyl alcohol copolymer; hereinafter referred to as “EVOH”), polyamide. A gas blown resin such as polyvinylidene chloride and polyacrylonitrile, a parison is formed by multilayer extrusion using the gas barrier resin as an intermediate layer, and a direct blow molding method for blow molding the parison;
After molding a plastic bottle, EVOH
(Japanese Patent Application Laid-Open No. 60-25 / 1985)
No. 1027), when the EVOH applied as described above absorbs moisture, the gas barrier property is reduced. To prevent this, a bottle is covered with a shrinkable film in which the surface of the barrier resin is covered with a hydrophobic resin. Method (Japanese Patent Publication Sho 62)
Although many proposals have been made, a stretch blow multi-layer bottle capable of maintaining high product strength even with a thin wall is expected as the most viable method. However, even in such a method, compared with the conventional single-layer PET bottle for soft drinks, there are problems of productivity (molding cycle), molding machine cost, cost of maintaining the molding machine and the mold, and further, recyclability. In response to this, a commonly used PET bottle molding machine can be used, and furthermore, the development of a high-functional thin-film coated single-layer PET bottle that satisfies the performance required for beer bottles is desired. I have.

[0007] Containers such as beer that only need to have a shelf life of a relatively short time after filling are usually 20 ° C and relative humidity even if they do not have perfect gas barrier properties like aluminum cans and glass bottles. Oxygen gas permeability at 65% is ² cc / m ² · day · atm or less, CO 2
_{2 If the} gas permeability is less than 20 cc / m ² · day · atm, 4 ~ 25 ° C required for beer containers
After storage for 300 days, the amount of infiltration of oxygen is 1 ppm or less based on the weight of the content beer, and the amount of carbon dioxide gas escaped after storage for 180 days is 1
A level of less than 0% can be secured. Therefore, it is necessary to develop a low-cost and recyclable high-functional thin-film coated single-layer plastic bottle having a gas barrier layer that satisfies the above criteria.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to a plastic bottle having an oxygen gas permeability of ² cc / m ² · day · atm or less at 20 ° C. and a relative humidity of 65%.
₍₂₎ Thermoplastic plastic bottles that can meet the conditions of gas permeability of 20 cc / m ² · day · atm or less, are inexpensive, lightweight, and have excellent impact resistance and recyclability due to simple surface treatment. It is an object of the present invention to develop a method of manufacturing a barrier plastic bottle that can use conventional plastic bottle equipment, has simple and inexpensive manufacturing equipment, and enables extremely high production speed.

[0009]

According to the present invention, there is provided [1] a barrier property wherein at least one of an outer surface and an inner surface of a plastic bottle is coated or surface-treated using atmospheric pressure low-temperature plasma. The plastic bottle, [2] the barrier plastic bottle according to the above [1], wherein at least one of the outer surface and the inner surface of the plastic bottle is coated with an organic or / and inorganic thin film, [3] the organic thin film in the thin film coating Is a plasma-polymerized thin film composed of a hydrocarbon polymer, a fluorine-containing polymer, and a nitrogen-containing polymer, and an inorganic thin film is a hydrocarbon compound thin film (D
LC: diamond-like carbon), a barrier plastic bottle according to the above [1] or [2], which is a plasma thin film coating that is a silicon compound thin film or a metal compound thin film, [4] at least the outer surface and the inner surface of the plastic bottle. The barrier plastic bottle according to the above [1], wherein one of the barrier plastic bottles is formed with an inert surface layer by surface treatment with an inert gas plasma or a reactive gas plasma.

[5] A method for producing a barrier plastic bottle, characterized in that at least one of the outer surface and the inner surface of the plastic bottle is coated with a thin film or a surface layer is formed by surface treatment by an atmospheric pressure low temperature plasma method, [6] Atmospheric-pressure glow discharge beam plasma generated by using an inert gas as a main gas when performing atmospheric-pressure low-temperature plasma coating is applied with organic and / or
Alternatively, a raw material capable of forming an inorganic thin film coating layer is supplied in gaseous form, and thin film coating is performed on at least one of the outer surface and the inner surface of the plastic bottle. Manufacturing method of plastic bottle, [7] Atmospheric pressure low temperature plasma surface treatment, using an atmospheric pressure glow discharge beam plasma and / or a reactive gas generated by using an inert gas as a main gas, The above-mentioned [5], wherein a surface-modified layer having a barrier property (an inert surface layer) is formed on at least one of the inner surfaces.
The above problem was solved by developing a method for manufacturing a barrier plastic bottle described in (1).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION When a barrier coating is applied, a method of not impairing the recyclability of a plastic bottle is to use the same barrier resin as the barrier coating or to apply the coating to the bottle. It is necessary to provide a negligible amount of barrier coating that does not affect the physical properties at all when mixed with the bulk resin. In the former method, there is no suitable good barrier resin in PET or PP, so the possibility cannot be found. On the other hand, when organic and / or inorganic coating is performed by atmospheric pressure low-temperature plasma, a coating having a barrier property can be obtained even with an extremely thin layer, and when a thermoplastic resin is surface-treated by rare gas plasma, the surface is modified. It is known that the surface is modified and similarly has a barrier property.

As a method of coating the barrier layer thin film, there are a plasma polymerization method using low-temperature plasma, a plasma CVD method, a sputtering method, an ion plating method and the like. Conventionally, in a low-temperature plasma state, a stable glow discharge under a low pressure has been used. Such a low-pressure glow discharge plasma device requires a high vacuum device, requires a large-scale device, and requires complicated peripheral devices. In addition, when considering an industrial manufacturing facility, the need for a high vacuum degree not only increases the equipment cost, but also has a serious drawback in the production speed. Therefore, the use of such a coating is extremely limited in industrialization at present.

Conventionally, it has been difficult to stably generate a low-temperature plasma state under atmospheric pressure. That is, the glow discharge could not be stably generated at the atmospheric pressure. It is known that it is due to the following reasons. At atmospheric pressure, an insulator is used in a low electric field, but when a high electric field such as a direct current, an alternating current, or an impulse is applied, a dielectric breakdown occurs and a current flows (self-sustaining discharge). The self-sustaining discharge is classified into corona discharge, glow discharge, and arc discharge. In the case of a uniform electric field, the entire circuit is immediately destroyed when the self-sustained discharge is started, and the glow discharge or the arc discharge is started. In the case of the non-uniform electric field, however, first, dielectric breakdown occurs only in a strong electric field, and corona discharge occurs. After that, if the electric field is further strengthened, the road will be destroyed. In the atmospheric pressure air, when the operation normally shifts to all-road breakdown, it often shifts quickly to arc discharge without going through glow discharge. The characteristic of arc discharge is thermionic emission (existence of a cathode luminescent spot) due to electrode heating caused by incident ions. However, at high pressure, the number of ions incident on the electrode is larger than at low pressure, so it is extremely high. It is considered that the electrodes are heated in a short time to emit thermoelectrons. It is also known that glow discharge occurs when the current is 2 A or less, but this is not practical because of poor controllability. Generally, arc discharge is used for applications such as welding and cutting.

In order to utilize glow discharge, attempts have been made to stably generate discharge at atmospheric pressure (S. Kan).
azawz et. al. J. Phys. D: App
l. Phys. 21 (1988) 838-840). For stable glow discharge at atmospheric pressure: 1. filling the discharge space with He; 2. Insert an insulator between the electrodes (in the discharge path); 3. at least one of the electrodes has a needle or brush shape; It is known that the frequency of the applied electric field should be 3 kHz or more as a necessary condition. By performing this, it is possible to cause the discharge to be performed relatively stably. In order to prevent the discharge from shifting to arc discharge in the insulator, the applied electric field frequency of 3 kHz or more causes a current to flow through the insulator. Therefore, if the electrode shape is a needle shape or a brush shape, the electric field is a non-uniform electric field. This is to make it easier to start discharge.

[0015] Based on such knowledge, stable glow discharge can be performed in the atmospheric pressure state, and active research and development are being advanced in this field. The rare gas is a gas composed of an element of Group 0 of the periodic table, such as helium, argon, neon, and xenon. These may be used alone or as a mixture of two or more. In this case, the treatment may be performed simultaneously with the coexistence of nitrogen or ammonia. The mixing amount of the hydrogen gas in the mixed gas is appropriately determined depending on the composition of the mixed gas used, the film forming pressure, and the like, and is not particularly limited.
In the present invention, the organic thin film in the thin film coating using the atmospheric pressure low temperature plasma is composed of a hydrocarbon polymer, a fluorine-containing polymer, and a nitrogen-containing polymer, and a plasma polymerization method is applied, and the inorganic thin film is a hydrocarbon compound thin film. (DLC: diamond-like carbon), silicon compound thin film, metal compound thin film,
A plasma CVD method is applied.

The raw material gas used for the thin film coating with a hydrocarbon polymer by the plasma polymerization method is greatly different from a polymerization mechanism in which a polymer chain grows simply by cleavage of a double bond as in a normal radical polymerization reaction. Therefore, as a monomer to be polymerized, almost any hydrocarbon compound such as a saturated hydrocarbon, an unsaturated hydrocarbon compound, and a cyclic hydrocarbon compound can be subjected to plasma polymerization. As a raw material gas used for thin film coating with a hydrocarbon compound by the plasma CVD method, a raw material gas containing carbon and hydrogen is usually used. Examples of such a raw material gas containing carbon and hydrogen include alkane-based gases such as methane, ethane, propane, butane, pentane and hexane; alkene-based gases such as ethylene, propylene, butene and pentene; butadiene and pentadiene. Alkadiene-based gases such as acetylene,
Alkyne gases such as methylacetylene, benzene,
Aromatic hydrocarbon gases such as toluene, xylene, indene, naphthalene and phenanthrene, cyclopropane,
Cycloalkane gases such as cyclohexane, cycloalkene gases such as cyclopentene and cyclohexene, alcohol gases such as methanol and ethanol, ketone gases such as acetone and methyl ethyl ketone, and aldehyde gases such as formaldehyde and acetaldehyde. And the like. The above gases may be used alone or in combination of two or more.

Other raw materials containing carbon and hydrogen include the above-mentioned mixture of gases and hydrogen gas, gases such as carbon monoxide gas or carbon dioxide gas, which consist only of carbon and oxygen, And mixtures of the hydrocarbon gases or hydrogen gases mentioned above. Further, as a raw material containing carbon and hydrogen, a mixed gas obtained by mixing a rare gas with the above-mentioned gases or mixed gases can be used.

The raw material gas used for the thin film coating of the fluorine-containing polymer by the plasma polymerization method includes a mixture of a saturated fluorinated paraffin such as C ₂ F ₆ + H ₂ and hydrogen, C ₂ F ₄ and C ₄ F _8. , An unsaturated fluorinated olefin such as C ₄ F ₆ and a fluorinated cyclic compound such as C ₆ F ₆ and C ₆ F ₁₀ . Raw material gases used for thin film coating with a nitrogen-containing polymer by a plasma polymerization method include acrylonitrile, nitrile compounds such as propionitrile, propylamine, amine compounds such as arylamine, mixtures of various hydrocarbons and nitrogen, Examples include mixtures of various hydrocarbons and ammonia.

Examples of the inorganic thin film formed by low-temperature plasma at atmospheric pressure include a silicon compound, a titanium compound, and a metal compound compound. Above all, a silicon compound can provide a thin film having excellent barrier properties and an inert surface. The raw material gas used for the thin film coating with the silicon compound by the plasma CVD method includes dimethoxy (methyl) silane, ethoxydimethyl silane, dimethoxy dimethyl silane, trimethoxy methyl silane, tetramethoxy silane, tetramethoxy silane, and dimethoxy as Si-containing organic substances. Methylvinylsilane, ethoxytrimethylsilane, diethoxymethylsilane, ethoxydimethylvinylsilane, allyltrimethylsilane, diethoxydimethylsilane, triethylsilane, hexamethyldisiloxane, hexamethyldisilane, diethoxymethylvinylsilane, triethoxymethylsilane, triethoxyvinylsilane , Bis (trimethylsilyl) acetylene, tetraethoxysilane, trimethoxyphenylsilane, γ-glycidoxyp Pill (dimethoxy) methylsilane, .gamma.-glycidoxypropyl (trimethoxy) methyl silane, .gamma.-methacryloxypropyl (dimethoxy)
Methylsilane, γ-methacryloxypropyl (trimethoxy) silane, dihydroxydiphenylsilane, diphenylsilane, triethoxyphenylsilane, tetraisopropoxysilane, dimethoxydiphenylsilane, diethoxydiphenylsilane, tetra-n-butoxysilane, tetraphenoxysilane, poly (Methyl hydrogen siloxane).

Examples of the metal compound for coating in the raw material gas used for the thin film coating with the metal compound by the plasma CVD method include the following. Ferrocene, acetylferrocene, monoethyl iron (II, III) fumarate, iron (II) fumarate
Salts, iron sources such as iron (II) gluconate / dihydrate, iron (III) acetylacetone, iron (III) decanoate, iron (III) stearate, etc .; cobalt (II) acetate / 4 hydrate ,
Acetylacetonate cobalt (II) salt, acetylacetone cobalt (III) salt, cyclohexyl butyrate cobalt salt,
Co sources such as dicobalt octacarbonyl; nickel formate (II) dihydrate, nickel acetylacetonate (II)
Salts, nickel sources such as nickel (II) acetate tetrahydrate; Cu sources such as copper hydroxycarbonate, copper acetate monohydrate, copper acetylacetonate (II), copper monoethyl fumarate; zinc acetate .2 Zn sources such as hydrated salts, diethyl zinc, zinc acetylacetonate (II) salt, zinc butyrate, zinc undecanoate;

Chromium sources such as acetylacetone chromium (III) salt, tris (1-phenyl-1,3-butanedionato) chromium salt (III) and chromium carbonyl; B sources such as diborane and boron chloride; aluminum chloride and aluminum boronide , Trimethylaluminum, aluminum sources such as aluminum acetylacetonate; titanium chloride, titanium iodide, titanium isopropoxide,
Ti sources such as Ti (OR) ₄ (R is a lower alkyl group); Mn sources such as dicyclopentadienyl manganese and manganese acetylacetonate; Ga sources of triethyl gallium; Ge sources of tetramethyl germanium; molybdenum carbonyl and molybdenum Mo sources such as chloride; In sources of triethylindium; Sn sources such as tetramethyltin and tin chloride; W sources such as tungsten carbonyl and tungsten fluoride;

Among them, silicon, aluminum, titanium and the like are preferable materials in view of cost and performance. Various gases for the above metal sources: hydrocarbons, nitrogen-containing compounds (nitrites, amines, etc.), fluorine-containing compounds, chlorine-containing compounds, and rare gases, such as simple gases such as nitrogen, hydrogen, and oxygen Are mixed to form a raw material gas.

Further, the surface treatment of the thermoplastic resin using low-temperature plasma at atmospheric pressure allows the surface to have an inert surface (not only to prevent gas barrier properties but also to elute all components from the bulk resin, As a method for modifying any components from a substance into a surface that does not adsorb), there is a method of performing a surface treatment with an inert gas plasma or a reactive gas plasma. The inert gas used in the present invention includes rare gases such as helium and argon, and the reactive gases include CF ₄ , NF ₃ , BF ₃ and Si.
Include those such as F _4.

In the present invention, the plasma polymerization film is formed by forming a plasma state by discharge at atmospheric pressure or a slightly reduced pressure in the plasma polymerization apparatus, and introducing the vaporized monomer there. The plasma formed by the discharge contains a wide variety of active species used for the polymerization reaction of high-energy electrons, ions, radicals, photons, etc., so the introduced low-molecular monomer gas is also activated and directly A polymer film can be obtained. Since plasma polymerization is an organic compound in which a monomer is easily decomposed thermally and is a coating on a plastic bottle, glow discharge, which is low-temperature plasma, is generally used. In the plasma obtained by glow discharge, 10
Although there are high-energy electrons reaching up to eV, most gases exist in a low energy state without ionization. Such plasma having different energy states is called non-equilibrium plasma, and when it is used for a plasma reaction of an organic compound, it is difficult to be thermally decomposed and is convenient. In order to form a stable glow discharge at a low temperature, a radio frequency (RF) of 13.56 MHz or a microwave of 2.45 GHz is mainly used.

As the monomer for polymerization, unlike the conventional chemical polymerization method, the above-mentioned various compounds having neither an unsaturated bond nor a specific functional group undergo polymerization and can be formed into a thin film. In general, the form of the monomer includes a gaseous or liquid organic compound, a sublimable solid organic compound, and the like at normal temperature and normal pressure, and polymerization is performed using one or a plurality of these.
In addition, an organometallic composite film in which metal particles are mixed into a polymer film by sputtering or heating and evaporating during the reaction can also be prepared. Since the structure and properties of the thin film depend on the plasma polymerization conditions, it is extremely important to find appropriate polymerization conditions for the purpose. Control factors in the plasma polymerization reaction: Plasma conditions: discharge frequency, output (voltage, current), electrode configuration (capacitive, inductive, no electrode, external electrode, internal electrode), distance between electrodes, area, etc., hydrodynamics Conditions: Degree of vacuum, reaction gas flow rate / flow rate, reaction gas concentration, reaction gas type, etc. Reactor conditions: There are reactor properties / shape, reactor temperature, electrode material, etc. It is important to form a film (for example, a high-density crosslinked insoluble or infusible film).

The plasma CVD film is formed by a chemical reaction using low-temperature plasma. The plasma generation method used in the plasma CVD apparatus for this purpose is diversified, and depending on the target film quality, film area, film growth rate, etc., DC plasma, low frequency plasma, high frequency plasma, pulse wave plasma, Plasma by pole structure, microwave plasma, downstream plasma,
A plasma CVD apparatus using columnar plasma, plasma assisted epitaxy, or the like can be used. Reaction parameters in plasma CVD include (1) gas type, (2) gas flow rate, (3) reaction pressure, (4) plasma power density, (5) plasma excitation frequency, (6) plasma generation method and electrode structure, (7) Plastic bottle temperature, (8) Electrode potential, (9) Plastic bottle position, (10) Bottle characteristics (change in thermal conductivity due to plastic type and composition, thermal expansion coefficient, filler, coloring material, etc.) ). Since there are many reaction parameters, various reaction conditions can be set, and various characteristics of a target substance can be relatively arbitrarily controlled.

The plasma surface treatment is a method of exposing a solid workpiece to a plasma atmosphere to physically or chemically change its surface properties. In the present invention, the surface treatment by plasma refers to surface modification by plasma using a non-polymerizable gas, and is distinguished from a technique using plasma, such as plasma polymerization. In other words, only the outermost layer (formation of skin layer) is modified, and a surface modification method that does not deposit a thin film on the surface layer like plasma polymerization or remove it from the surface like etching is used. is there. The surface treatment with a non-polymerizable gas is further roughly classified into two types depending on the type of gas, and the present invention means both of them. That One is not chemically react helium, an inert gas such as argon, other one is hydrogen, oxygen, nitrogen, water vapor, ammonia, although not polymerized as CF ₄ participate in chemical reactions Things.

The present invention provides an apparatus for generating a cylindrical plasma in an open system at atmospheric pressure without the need for a reaction vessel and an exhaust device, thereby providing an inner or outer surface of a beverage plastic bottle in an open system. This enables high-speed barrier thin film coating. Hereinafter, atmospheric pressure low temperature plasma polymerization and plasma CV which can be used in the present invention
D, an embodiment of an apparatus capable of performing plasma surface treatment will be described with reference to FIG. 1 (outer surface coating apparatus) and FIG. 2 (inner surface coating apparatus). An outline of components used in the apparatus will be briefly described.

FIG. 1 shows an embodiment of an apparatus for plasma coating the outer surface of a plastic bottle and how to operate the apparatus. The plastic bottle 1 is fixed to the insulating support 4 and covered with the outer conductor 2. The rotatable center conductor 3 is inserted into the plastic bottle 1 and plasma is generated while rotating. An AC power supply 5 is connected to the outer conductor 2, and an inert gas supply source such as helium or argon and a reaction gas supply source 9 via a flow rate control device 7 are provided in a discharge space 6 between the outer surface of the plastic bottle and the outer conductor 2. The plasma coating is performed while supplying an inert gas and a reactive gas from the above. When the reaction gas is liquid, the reaction gas evaporator 10 is used to pass the inert gas as a carrier gas.

FIG. 2 shows an embodiment of an apparatus for plasma coating the inner surface of a plastic bottle and how to operate the apparatus. The plastic bottle 1 is fixed to the insulating support 4 and covered with the outer conductor 2 connected to the AC power supply 5. Next, the center conductor 3 having a hollow inside and having a structure capable of flowing an inert gas such as helium or argon and a reaction gas is inserted into the plastic bottle 1, and plasma is generated while rotating. Discharge space 6 inside plastic bottle 1 and between outer conductor 2 and center conductor 3
Next, plasma coating is performed while supplying an inert gas and a reactive gas from the inert gas supply source 8 and the reactive gas supply source 9 via the flow rate controller 7 and the central conductor 3. When the reactive gas is liquid, the reactive gas evaporator 10 is used.

[0031]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. The thermoplastic resin used in the examples was PET [Unipet RT543: intrinsic viscosity (IV = 0.75) manufactured by Nippon Unipet Co., Ltd.]. For the plastic bottle, a single-layer injection molding machine (75 tons of Sumitomo Heavy Industries Cycap) was used to mold the PET at a cylinder temperature of 280 ° C and a mold temperature of 10 ° C.
T resin is introduced into the hopper and the preform (weight 31
g, height 110 mm, diameter 25 mm). Then, the preform was adjusted to a temperature of 100 ° C. using a stretch blow molding machine manufactured by Krupp Co., and stretch blow-molded using compressed air to have a capacity of 500 ml and an average wall thickness of the bottle body of 350 μm and a height of 180 mm. A bottle sample was obtained.

Example 1 A helium gas containing 5% of acetylene was used as a reaction gas, and a thin film composition: DLC was manufactured. The PET bottle (for 500 ml) obtained above is set in the inner surface coating device. Thereafter, a mixed gas of helium gas and reaction gas (helium gas containing 5% of acetylene) is continuously supplied at 100 cc / min. Three minutes later, a power of 13.56 MHz · 105 W was supplied from a high frequency power supply to bring the discharge space into a plasma state. The DLC film was deposited for one minute and the power was turned off.

Example 2 A helium gas containing 5% of acetylene was used as a reaction gas, and a thin film composition: DLC was manufactured. PET bottle (500
(for ml). After that, a mixed gas of helium gas and a reaction gas (helium gas containing 5% of acetylene) was added to 10
Supply is continued at 0 cc / min. Three minutes later, a power of 13.56 MHz · 105 W was supplied from a high frequency power supply to bring the discharge space into a plasma state. Deposit the DLC film for 1 minute,
I turned off the power.

Example 3 A plastic bottle having a thin film composition: DLC was manufactured by performing plasma coating in the same manner as in Example 1 except that a helium gas containing 5% of methane was used as a reaction gas using an inner surface coating apparatus. . (Example 4) in surface-coating apparatus, except using tetramethoxysilane 2% containing helium gas was likewise plasma coating as in Example 1 film composition as the reaction gas: obtain a plastic bottle SiO _2.

(Example 5) Plasma coating was performed in the same manner as in Example 1 except that a helium gas containing SiH ₄ / NH ₃ : 2% / 2% was used as a reaction gas using an inner surface coating apparatus, and a thin film composition was prepared. : A plastic bottle of SiN ₂ was obtained. (Example 6) Plasma coating was performed in the same manner as in Example 1 except that a helium gas containing AlCl ₃ / NH ₃ : 2% / 2% was used as a reaction gas using an inner surface coating apparatus, and a thin film composition: Al ₂ O was used. I got ₃ plastic bottles.

Example 7 A plastic bottle of thin film composition: TiO ₂ was formed by plasma coating in the same manner as in Example 1 except that an inner surface coating apparatus was used and a helium gas containing 2% of tetraisopropoxytitanium was used as a reaction gas. I got (Example 8) A plastic bottle having a thin film composition: nitrogen-containing polymer was obtained by plasma coating in the same manner as in Example 1 except that helium gas containing 10% of acrylonitrile was used as a reaction gas using an inner surface coating apparatus. Example 9 Plasma coating was performed in the same manner as in Example 1 except that an inner surface coater was used and argon gas containing 10% of CF ₂ = CF ₂ was used as a reaction gas. Thin film composition: Fluorine-containing polymer plastic bottle Obtained.

(Embodiment 10) Using an inner surface coating apparatus,
A plastic bottle having a skin layer having a surface cross-linked on the inner surface of the bottle was obtained by performing surface treatment with plasma in the same manner as in Example 1 except that argon was used as an inert gas. (Example 11) A plastic bottle having a skin layer whose surface was fluorinated was obtained by performing plasma surface treatment in the same manner as in Example 1 except that an argon gas containing 5% of NF ₃ was used as a reaction gas. Comparative Example 1 A single-layer PET bottle was used as a sample without any treatment.

(Evaluation Method) The gas barrier properties of the bottle samples of Examples 1 to 11 and Comparative Example 1 were measured by the following method. Table 1 shows the results. 1) Oxygen permeability The oxygen permeability was measured using OX-TRAN2 / 20ML manufactured by Mocon. The measurement conditions are 23 ° C. and 65% RH for both the inner and outer surfaces. 2) Oxygen penetration Ingol equipped with a soft package sampling device
d Using a polarographic oxygen sensor model IL 307 manufactured by Instruments, the period until the oxygen concentration in the head space completely replaced with carbon dioxide gas reached 1 ppm due to oxygen entering from the atmosphere was measured. Storage condition: temperature 23 ° C: relative humidity 100% inside the bottle, 65% outside

3) Amount of carbon dioxide gas loss A 500 ml bottle sample was charged with 500 ml of carbonated water of gas volume 3. The change over time of the weight was measured, and the number of days required for the loss of carbon dioxide gas to reach 10% was determined. Storage conditions: temperature 23 ° C .: relative humidity 100% RH inside bottle, 65% RH outside Measured in a carbonated water-filled container equivalent to 2) above.

4) Relative transparency to PET Single-layer PE having the same shape as the bottle used in Examples and Comparative Examples
A T bottle was molded and its transparency was compared. Sampling should be performed from the same layer thickness as much as possible, and a wavelength of 40
The light transmittance from 0 nm to 700 nm is measured by U (manufactured by Shimadzu Corporation).
It measured using V-160. Specific transparency with respect to PET (%) = [Integration of light transmittance of 400-700 nm bottles of Examples and Comparative Examples] ÷ [Single-layer PE
Integration of light transmittance at 400 to 700 nm of T bottle] × 10
0

[0041]

[Table 1]

[0042]

According to the gas barrier plastic bottle of the present invention, a conventional single-layer PET bottle is used, and at least one of the inner surface and the outer surface has an organic or / and inorganic barrier thin film coating or an inert gas plasma or An object of the present invention is to provide a beer bottle having an extremely high oxygen barrier property and a carbon dioxide gas in which a barrier surface layer is formed by a surface treatment using reactive gas plasma. Also,
The present invention provides an apparatus for generating a cylindrical plasma in an open system at atmospheric pressure without the need for a reaction vessel and an exhaust device, whereby an inner surface or an outer surface of a plastic bottle for beverages can be formed at a high speed in an open system. When considering industrial manufacturing equipment that enables barrier thin film coating and does not require high vacuum equipment such as conventional low pressure glow discharge plasma equipment and complicated peripheral equipment, not only equipment cost,
The production speed is also very good. Therefore, application development is expected in industrialization in the future.

[Brief description of the drawings]

FIG. 1 is an outline of a plastic bottle outer surface coating apparatus.

FIG. 2 is an outline of a plastic bottle inner surface coating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic bottle 2 Outer conductor 3 Center conductor 4 Insulating support 5 AC power supply 6 Discharge space 7 Flow controller 8 Gas cylinder 9 Gas cylinder 10 Evaporator

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kensuke Onishi 3-6-5 Iidabashi, Chiyoda-ku, Tokyo Showa Aluminum Can Co., Ltd. F-term (reference) 3E033 AA01 BA13 BB08 CA03 CA14 CA16 DB01 DD05 EA10 GA02 4F073 AA16 AA17 BA24 BB03 CA01 CA02 CA65 CA70 CA72 HA01 HA09 HA11 HA12 4K030 AA04 AA06 AA09 AA11 AA13 AA16 BA01 BA02 BA18 BA28 BA29 BA35 BA40 BA44 BA46 BA61 CA07 CA11 FA01 JA09 LA01 LA24

Claims (7)

[Claims] 1. A barrier plastic bottle, wherein at least one of an outer surface and an inner surface of the plastic bottle is coated or surface-treated using atmospheric pressure low-temperature plasma. 2. The barrier plastic bottle according to claim 1, wherein at least one of the outer surface and the inner surface of the plastic bottle is coated with an organic or / and inorganic thin film. 3. In a thin film coating, when it is an organic thin film, a hydrocarbon polymer, a fluorine-containing polymer,
3. A plasma thin-film coating comprising a nitrogen-containing polymer, wherein the inorganic thin film is a plasma thin-film coating comprising a hydrocarbon compound thin film (DLC: diamond-like carbon), a silicon compound thin film, or a metal compound thin film. A barrier plastic bottle as described. 4. The barrier plastic bottle according to claim 1, wherein at least one of the outer surface and the inner surface of the plastic bottle has a surface treated with inert gas plasma or reactive gas plasma to form an inert surface layer. 5. A method for producing a barrier plastic bottle, characterized in that at least one of an outer surface and an inner surface of a plastic bottle is coated with a thin film or a surface layer is formed by surface treatment by an atmospheric pressure low temperature plasma method. 6. An atmospheric pressure glow discharge beam plasma generated by using an inert gas as a main gas at the time of atmospheric pressure low temperature plasma coating, using a raw material capable of forming an organic and / or inorganic thin film coating layer as a gas. The method for producing a barrier plastic bottle according to claim 5, wherein the plastic bottle is supplied in a form and at least one of an outer surface and an inner surface of the plastic bottle is coated with a thin film. 7. At least one of an outer surface and an inner surface of a plastic bottle is subjected to an atmospheric pressure low temperature plasma surface treatment using an atmospheric pressure glow discharge beam plasma generated by using an inert gas as a main gas and / or a reactive gas. 6. The method for producing a barrier plastic bottle according to claim 5, wherein a barrier surface modified layer (inactive surface layer) is formed on one side.