JP2006008254A - Device for forming barrier film at inner surface of plastic container and method for manufacturing inner surface barrier covered plastic container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for forming a barrier film at an inner surface of a plastic container capable of coating a superior quality film having a uniform thickness at the inner surface of a plastic container, reducing a maintenance work and satisfying a low requisite mechanical precision of the device. <P>SOLUTION: This device comprises an external electrode enclosing a plastic container of processed item when the container is inserted, a grounded gas exhausting pipe fixed to an end surface of the external electrode at a side where an opening of the container is positioned through an insulating member, an exhausting means for exhausting gas in the plastic container inserted into the external electrode through the gas exhausting pipe, gas supplying means for supplying raw material gas into the plastic container inserted into the external electrode and a high frequency power supply connected to the external electrode. A conductive member having a gas flowing hole is arranged in the exhaust pipe while being contacted with the inner surface of the exhaust pipe. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for forming a barrier film on the inner surface of a plastic container and a method for producing an inner barrier film-coated plastic container.

  A plastic container, for example, a PET bottle, is coated with a carbon film such as DLC (Diamond Like Carbon) on its inner surface in order to prevent the permeation of oxygen from the outside and the permeation of carbon dioxide from the inside (for example, carbonated drinking water). It has been tried.

  Plastic containers, such as PET bottles, permeate oxygen from the outside and leaching into the container itself, such as oxygen and acetaldehyde, carbon dioxide from inside (for example, carbonated drinking water), water evaporation , DLC (Diamond Like Carbon) or a-C (amorphous Carbon) on the inner surface to prevent the flavor from adsorbing to the bottle and to prevent the contents from deteriorating due to the sunlight entering the bottle. Attempts have been made to coat various functional barrier films, such as carbon films and SiOx films, that have the property of preventing the transmission of gas or light.

  As a method of coating a barrier film on the inner surface of a plastic container such as a PET bottle, Patent Document 1, Patent Document 2, Patent Document 3, and the like are disclosed. Non-patent document 1 and non-patent document 2 are collectively reported.

  Patent Document 3 and Patent Document 4 disclose a method using high-frequency plasma. Patent Document 5 discloses a method of coating a film with a carbon film using high-frequency plasma as an applied method. Patent Document 6 discloses a carbon film coating method corresponding to a specially shaped container, and Patent Document 7 discloses a method of simultaneously coating a plurality of containers as a mass production technique. Non-Patent Document 3 discloses a technique for coating a plastic container with a carbon film.

  Furthermore, if the source gas is changed, other functional films such as SiOx can form high-frequency plasma.

  A method of coating a carbon functional barrier film on a plastic container using high-frequency plasma CVD based on Patent Document 1 will be described below.

  FIG. 8 is a cross-sectional view of a carbon film coating apparatus on the inner surface of a plastic container using high-frequency plasma CVD described in Patent Document 1.

  In FIG. 8, 101 is an external electrode canopy part, 102 is an external electrode, 103 is an insulating plate, 104 is a plastic container, 105 is an internal electrode, 106 is a gas supply port, 107 is a plastic internal space, 108 is a plastic container 104 and an electrode. (Plastic outer cylinder), 109 is a mouth of the container 104, 110 is a source gas supply pipe, 111 is an exhaust port, 112 is a matching box, 113 is a high-frequency power source, 114 is cooling water, and 115 is a plastic outer cylinder. It is. In this example, the ground electrode is an internal electrode 105 inserted into the container 104. Further, the external electrode 102 also serves as a film forming chamber. A plastic outer cylinder 115 is installed inside the external electrode 102 so that there is no gap between the outer cylinder 115 and the plastic container 104, and there is no large space other than the inside of the plastic container 104. It has a structure.

  A method of coating a carbon film on the inner surface of a plastic container such as a plastic bottle using the apparatus having the configuration shown in FIG.

  First, a plastic container 104 such as a plastic bottle is inserted into a plastic outer cylinder 115 installed inside the external electrode 102. The gas in the external electrode 105 is exhausted through the gas exhaust port 111. At this time, the gas in the space inside and outside the plastic container 104 stored in the outer cylinder 115 is exhausted. After reaching the prescribed degree of vacuum (representative value: 10 −2 to 10 −5 Torr), the medium gas is supplied to the internal electrode 105 through the source gas supply pipe 110 at a flow rate of, for example, 10 to 50 mL / min. The gas is supplied into the plastic container 104 through the gas supply port 106. Examples of the medium gas include aliphatic hydrocarbons such as acetylene, benzene, toluene, xylene, and cyclohexane, aromatic hydrocarbons, oxygen-containing hydrocarbons, and nitrogen-containing hydrocarbons. When a functional film of SiOx is formed instead of the carbon film, for example, by changing the medium gas, such as using a mixture of hexamethyldisiloxane (HMDSO) or tetraethoxysilane (TEOS) and oxygen gas. Various barrier films can be coated.

The pressure in the plastic container 104 is set to 2 × 10 ⁻¹ to 1 × 10 ⁻² Torr according to the balance between the gas supply amount and the exhaust amount. Thereafter, high frequency power of 50 to 1000 W is applied to the external electrode 102 through the matching unit 112 from the high frequency power source 113.

By applying such high frequency power to the external electrode 102, plasma is generated between the external electrode 102 and the internal electrode 105. At this time, since the plastic container 104 is accommodated in the plastic outer cylinder 115 installed inside the external electrode 102 with almost no gap, plasma is generated in the plastic container 104. The medium gas is dissociated or further ionized by the plasma to generate a film-forming species for forming a carbon film, and this film-forming species is deposited on the inner surface of the plastic container 104 to form a carbon film. After the carbon film is formed to a predetermined thickness, the application of high-frequency power is stopped, the supply of medium gas is stopped, the exhaust of residual gas, nitrogen, rare gas, air, or the like is supplied into the external electrode 102, and this space Return inside to atmospheric pressure. Thereafter, the plastic container 104 is removed from the external electrode 102. In this method, it takes 2-3 seconds to form a carbon film with a thickness of 30 nm.
Japanese Patent Laid-Open No. 2-70059 JP 2000-230064 JP-A-8-53116 JP-A-8-53117 JP 9-272567 A Japanese Patent Laid-Open No. 10-226884 Japanese Patent Laid-Open No. 10-258825 Shunzo Miyazaki, “Plasma coating technology for PET bottles”, molding, “Vol. 14, no. 3, p. 153, 2002 Shirakura, “DLC coating on PET bottles”, Surface Technology, Vol. 52, no. 12, p. 853, 2001 K. Takemoto, et al, Proceedings of ADC / FCT '99, p285, '' E. Shimamuraet al, 10th years IAPRI World Conference 1997, p251

  However, the above-described invention of Patent Document 1 has the following problems.

  That is, plasma is generated in the plastic container 104 by supplying high-frequency power to the external electrode 102 and grounding the internal electrode 105 inserted into the plastic container 104, and the internal electrode 105 is always exposed to plasma. . Therefore, while the medium gas is dissociated in plasma and the inner surface of the plastic container 104 is coated with the barrier film, the surface of the internal electrode 105 is also coated (attached). Such coating (adhesion) of the barrier film on the surface of the internal electrode 105 is inconvenient in the following points.

  a) The gas supply port 106 of the internal electrode 105 becomes clogged, making it difficult to stably blow out the medium gas.

  b) Since the barrier film on the surface of the internal electrode 105 is an insulating film, if a large amount of film is deposited, the discharge state between the internal electrode 105 and the external electrode 102 (in the plastic container 104) changes, and the plasma The generation may become unstable or the plasma may not turn on, and the coating may not be achieved.

  The above a) and b) not only cause the film thickness of the barrier film coated on the inner surface of the plastic container 104 to be non-uniform, but also cause a deterioration of the film quality and a large number of defective products without a film during mass production. Cause it.

  c) The internal electrode 105 to which the carbon film is attached has a thin outer diameter, so that the electric field concentrates, and if the gas phase reaction in the plasma proceeds excessively, it becomes a powdery substance that can be mixed into the beverage and is plastic It adheres to the inner surface of the container 104.

  d) The carbon film deposited on the internal electrode 105 peels off, remains in the plastic container 104, and mixes as a foreign substance in the beverage.

  In order to avoid such problems, it is necessary to frequently clean the surface of the internal electrode, which not only complicates the maintenance work but also reduces the productivity of the carbon barrier film-coated plastic container.

  In addition, in a carbon film coating apparatus in which an internal electrode is provided in a plastic container, when the plastic container is inserted into and removed from the film forming chamber, the internal electrode is inserted into the opening of the plastic container. When the plastic container is taken in and out so as not to hit the mouth, mechanical accuracy and mechanical accuracy of the internal electrode position are required, and the apparatus becomes complicated.

  e) Further, in the carbon film coating apparatus in which the internal electrode is provided in the plastic container, when the axis of the internal electrode and the plastic container or the external electrode is misaligned, the internal electrode and the plastic container are formed particularly in the mouth portion where the inner diameter of the plastic container is thin. There is a problem that a non-uniform electric field is generated between the mouth portions, and thus non-uniform discharge occurs, resulting in a non-uniform film distribution in the circumferential direction.

  Such a problem also applies to functional films such as SiOx other than carbon films.

  The present invention is a plastic container that has a good film quality on the inner surface of the plastic container, can be coated with a barrier film having a uniform thickness, reduces maintenance, and requires less mechanical precision of the apparatus. An object of the present invention is to provide an apparatus for forming a barrier film on the inner surface.

  An object of the present invention is to provide a method for producing a plastic container having a good film quality and having a uniform film thickness coated on the inner surface.

An apparatus for forming a barrier film on the inner surface of a plastic container according to the present invention includes an external electrode surrounding the container when the plastic container as the object to be processed is inserted,
An exhaust pipe attached to the end face of the external electrode on the side where the mouth of the container is located via an insulating member, and grounded;
An exhaust means for exhausting the gas in the plastic container inserted into the external electrode through the exhaust pipe;
Gas supply means for supplying a raw material gas to the plastic container inserted into the external electrode;
A high frequency power source connected to the external electrode,
The conductive member having a gas flow hole is provided in the exhaust pipe in contact with the inner surface of the exhaust pipe.

The method for producing an inner surface barrier film-coated plastic container according to the present invention, in producing an inner surface barrier film-coated plastic container using a barrier film forming apparatus,
(A) inserting a plastic container as an object to be processed into the external electrode;
(B) after exhausting the gas in the container through an exhaust pipe by an exhaust means, supplying a raw material gas into the plastic container by a gas supply means, and setting the plastic container to a predetermined gas pressure;
(C) A high-frequency power is supplied from a high-frequency power source to the external electrode, and a high-frequency electric field is confined in the container-side space from the conductive member by a conductive member, and plasma generation is regulated in the space. And a step of coating the inner surface of the plastic container with a barrier film.

  According to the present invention, it is possible to coat the inner surface of the plastic container with a good film quality on the inner surface of the plastic container, further capable of coating a barrier film having a uniform thickness, reducing maintenance, and performing stable operation. A barrier film forming apparatus can be provided.

  In addition, according to the present invention, it is possible to provide a method capable of producing a plastic container having a good film quality and having a uniform film thickness coated on the inner surface and having an excellent barrier property against oxygen, carbon dioxide and the like. .

Hereinafter, the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a sectional view showing an apparatus for forming a barrier film on the inner surface of a plastic container according to the first embodiment.

  A cylindrical support member 2 having flanges 1 a and 1 b at the upper and lower ends is placed on an annular base 3. A metal external electrode body 4 is disposed in the support member 2. A disk-shaped metal external electrode bottom member 5 is detachably attached to the bottom of the external electrode 4. The external electrode main body 4 and the external electrode bottom member 5 constitute a bottomed cylindrical external electrode 6 having a space of a size capable of installing a plastic container (for example, a plastic bottle) B that forms a carbon film. A columnar spacer 7 made of an insulating material is installed in the space between the upper inner side of the external electrode main body 4 and the mouth and shoulder of the PET bottle B. The disk-shaped insulator 8 is disposed between the base 3 and the external electrode bottom member 5.

  The external electrode bottom member 5, the disk-shaped insulator 8, and the base 3 are integrally moved up and down with respect to the external electrode main body 4 by a pusher (not shown) to open and close the bottom of the external electrode main body 4. To do.

  The annular insulating member 9 is placed on the upper surface of the external electrode 6 so that the upper surface of the annular insulating member 9 is flush with the upper flange 1 a of the cylindrical support member 2. A gas exhaust pipe 11 having upper and lower flanges 10 a and 10 b is placed on the upper flange 1 a of the support member 2 and the upper surface of the annular insulating portion 9. The exhaust pipe 11 is grounded. The gas exhaust pipe 11 is fixed to the support member 2 by screwing screws (not shown) from the lower flange 10 b of the exhaust pipe 11 to the upper flange 1 a of the support member 2. Further, by screwing a screw (not shown) from the lower flange 10 b of the exhaust pipe 11 through the annular insulating portion 9 to the main body 4 of the external electrode 6, the main body 4 of the external electrode 6 is attached to the exhaust pipe 11. It is suspended via the annular insulating member 9. The exhaust pipe 11 and the annular insulating member 9 and the external electrode 6 are fixed in a mounting structure in which the exhaust pipe 11 and the external electrode 6 are not electrically connected by screws. The branch gas exhaust pipe 12 is connected to the side wall of the gas exhaust pipe 11, and an exhaust facility such as a vacuum pump (not shown) is attached to the other end. The lid 13 is attached to the upper flange 10 a of the exhaust pipe 11.

  For example, a high frequency power supply 14 that outputs high frequency power having a frequency of 13.56 MHz is connected to the main body 4 of the external electrode 6 through a cable 15 and a power supply terminal 16. The matching unit 17 is interposed in the cable 15 between the high-frequency power source 14 and the power supply terminal 16.

  The gas supply pipe 18 passes through the lid body 13 and is inserted into the gas exhaust pipe 11 in the vicinity of the mouth of the plastic bottle B inserted into the external electrode 6. The gas supply pipe 18 is of an attachment type so that the length and material can be changed, and is selectively used depending on the coating conditions. When the gas supply pipe 18 is inserted from the mouth of the plastic bottle B to the vicinity of the bottom, the gas supply pipe portion 19 located in the plastic bottle B is an insulator as indicated by a broken line.

  The columnar spacer 7 has, for example, a hollow portion into which a mouth portion of a PET bottle is inserted. Examples of the insulating material constituting the spacer 7 include plastic or ceramic. Various plastics can be used, and a fluorine-based resin such as polytetrafluoroethylene having a low high-frequency loss and excellent heat resistance is particularly preferable. As the ceramic, alumina, steatite with low high-frequency loss, or Macor with high machinability is preferable.

  Next, a method for producing an inner surface carbon film-coated plastic container will be described using the barrier film forming apparatus shown in FIG.

  The external electrode bottom member 5, the disk-shaped insulator 8, and the base 3 are removed by a pusher (not shown) to open the bottom of the external electrode body 4. Subsequently, after inserting a plastic container, for example, a plastic bottle B from the bottom side of the external electrode body 4 opened from the mouth side of the bottle B, the external electrode bottom member 5 is placed on the bottom side of the external electrode body 4 by a pusher (not shown). By attaching the disk-shaped insulator 8 and the base 3 in this order, the plastic bottle B is attached to the external electrode body 4 and the external electrode bottom member 5 as shown in FIG. 7 is stored in the internal space. At this time, the plastic bottle B communicates with the exhaust pipe 11 through its mouth.

  Next, the gas inside the exhaust pipe 12 and the PET bottle B is exhausted through the branch exhaust pipe 12 and the exhaust pipe 12 by an exhaust means (not shown). At the same time, the gas present in the gap between the plastic bottle B and the external electrode 6 is also exhausted. Subsequently, a raw material gas, for example, a medium gas is supplied into the inside of the PET bottle B through the gas supply pipe 18. Thereafter, the gas supply amount and the gas exhaust amount are balanced, and the inside of the plastic bottle B is set to a predetermined gas pressure.

  Next, for example, high frequency power having a frequency of 13.56 MHz is supplied from the high frequency power source 14 to the main body 4 of the external electrode 6 through the cable 15, the matching unit 17, and the power supply terminal 16. At this time, discharge is performed between the external electrode 6 and the grounded exhaust pipe 11, and plasma is generated in the PET bottle B inserted into the external electrode 6. Since there is no metal electrode inside, a discharge occurs between the external electrode 6 and the exhaust pipe 11. Due to the generation of such plasma, the medium gas is dissociated by the plasma, and a uniform carbon film having a uniform thickness is coated on the inner surface of the PET bottle B.

  After the thickness of the carbon film reaches a predetermined thickness, the supply of the high frequency power from the high frequency power supply 14 is stopped, the supply of the medium gas is stopped, the residual gas is exhausted, and the exhaust of the gas is stopped. Then, nitrogen, rare gas, air, or the like is supplied into the PET bottle B through the gas supply pipe 18, the inside and outside of the PET bottle B is returned to atmospheric pressure, and the inner surface carbon film coated PET bottle is taken out. Thereafter, the plastic bottle B is exchanged according to the above-described order, and the next plastic bottle coating operation is started.

  The medium gas is basically hydrocarbon, for example, alkanes such as methane, ethane, propane, butane, pentane and hexane; alkenes such as ethylene, propylene, butene, pentene and butadiene; alkynes such as acetylene; benzene Aromatic hydrocarbons such as toluene, xylene, indene, naphthalene and phenanthrene; cycloparaffins such as cyclopropane and cyclohexane; cycloolefins such as cyclopentene and cyclohexene; oxygen-containing hydrocarbons such as methyl alcohol and ethyl alcohol; Nitrogen-containing hydrocarbons such as methylamine, ethylamine and aniline can be used, and other carbon monoxide and carbon dioxide can also be used.

  The frequency of the high-frequency power is generally 13.56 MHz, but the same processing can be expected in the range of 100 kHz to 400 MHz, for example. In general, the lower the frequency, the higher the bias voltage, and the better the barrier film. However, the film formation rate is slow. On the other hand, the higher the frequency, the higher the film formation speed due to the effect of increasing the plasma density, but the film quality decreases. The optimum frequency is determined by the trade-off between the two. The power used is 100 to 1000 W, but is not limited thereto. Further, these powers may be applied continuously or intermittently (pulse-like), or a negative DC pulse having a pulse width of 100 ns or less that functions in the same manner as a high frequency may be applied.

  As described above, according to the first embodiment, the discharge is performed between the external electrode 6 and the grounded exhaust pipe 11, and plasma is generated in the plastic bottle B inserted into the external electrode 6. The tip (lower end) of the gas supply pipe 18 for supplying gas can be positioned in the gas exhaust pipe 11 near the mouth of the plastic bottle B inserted into the external electrode 6, for example. For this reason, since the generation of the plasma and the dissociation of the raw material gas (for example, the medium gas) can be performed in the state where the internal electrode is not present in the PET bottle B as in the prior art, stable plasma generation can be achieved. it can. As a result, a carbon film having good film quality and a uniform film thickness can be coated on the inner surface of the PET bottle B. Moreover, the complicated maintenance operation for cleaning the internal electrode which exists in the PET bottle B can be eliminated. In addition, since the carbon film can be prevented from being coated on the internal electrode, the coating speed of the carbon film on the inner surface of the PET bottle B can be improved.

  Even if the tip of the gas supply pipe 18 is stopped at the upper end of the mouth of the PET bottle B depending on the property of the medium gas, the amount of inflow, and the pressure in the PET bottle B, there may be a uniform coating. If it is not inserted from the mouth part to the bottom part, it may become non-uniform. For example, when the pressure of the plastic bottle B is 200 mTorr to 1 Torr, the upper part becomes a thick coating unless the tip of the gas supply pipe 18 is inserted to the bottom. On the other hand, in the case of 200 mTorr or less or 1 Torr or more, a uniform coating was obtained by installing the tip of the gas supply pipe 18 in the vicinity of the PET bottle mouth. When the gas supply pipe 18 is inserted from the mouth part to the bottom part of the plastic bottle B, the gas supply pipe part 19 is made of an insulator to eliminate electrical influences and avoid adhesion of the film. Instability of the discharge caused by electrical impedance mismatching can be avoided even if it is deposited.

  In the first embodiment, the exhaust pipe has the role of a ground electrode instead of having no internal electrode. However, as a result of experiments, it has been found that discharge instability due to contamination of the exhaust pipe hardly occurs. That is, in the conventional case with an internal electrode, discharge instability occurs after several tens of coatings, but in the first embodiment, discharge instability does not occur even when coating is performed 1000 times or more. This is because the internal electrode has a small diameter and the electric field is concentrated, which tends to be affected by the adhesion of the film, and because the exhaust pipe is downstream of the discharge, the gas mainly composed of the remaining hydrogen used as the source gas This is probably because the film formation rate on the exhaust pipe is low because the film formation rate is low.

  Further, when the gas supply pipe 18 cannot be made of an insulator due to mechanical strength or the like and is made of metal, the raw material gas is not supplied to the inside of the plastic bottle B due to the condition such as gas pressure. There may be cases where high-quality coating cannot be achieved. Also in this embodiment, if the insertion depth of the tip of the gas supply pipe 18 is from the mouth of the plastic bottle B to 1/4 of the total height of the plastic bottle, the discharge mainly occurs between the external electrode 6 and the exhaust pipe 11. During the period, the plasma is widely generated from the inside of the PET bottle B to the exhaust pipe, and even if the gas supply pipe 18 is contaminated with a barrier film, the discharge becomes unstable or the discharge occurs. It turns out that it never happens.

In addition, if the gas supply pipe has the length, there is no problem that complicates handling when inserting the plastic bottle. When the metal gas supply pipe is inserted to a depth of 1/4 or more of the total height of the PET bottle, the discharge may become unstable or the discharge may not occur.

Therefore, according to the first embodiment, mass production of an inner surface carbon barrier film-coated PET bottle with excellent barrier properties that prevents the permeation of oxygen from the outside and the permeation of carbon dioxide from the inside (for example, carbonated drinking water). can do.

(Second Embodiment)
FIG. 2 is a sectional view showing an apparatus for forming a barrier film on the inner surface of a plastic container according to the second embodiment.

  A cylindrical support member 22 having flanges 21 a and 21 b at the upper and lower ends is placed on an annular base 23. A storage member 24 that stores a plastic container (for example, a plastic bottle) B that forms a carbon film is disposed in the cylindrical support member 22 and the annular base 23.

  The storage member 24 includes a cylindrical body 25 in which an upper portion that surrounds the outer periphery of the plastic bottle B when the plastic bottle B is inserted, and a disk-shaped material made of a conductive material disposed at the bottom of the cylindrical body 25. And a bottom plate 26. The cylindrical body 25 includes a first annular electrode (annular upper electrode) 27, an annular insulator 28, and a second annular electrode (annular lower electrode) 29 that are divided into three in the height direction. A cylindrical spacer 30 made of an insulating material is disposed on the upper portion of the upper portion of the plastic bottle B and the upper portion of the cylindrical body 25 located inside the first annular electrode 27, and an adhesive is interposed therebetween. Are fixed to each other. At the lower end of the annular upper electrode 27, a metal projection 31 extends thinly between the inside of the annular insulator 28 and the outer periphery of the plastic bottle B. An exterior cylindrical body made of an insulating material (not shown) is disposed on the outer periphery of the cylindrical body 25 to prevent a positional shift of the cylindrical body 25 made of each of the divided members. The annular upper electrode 27 is grounded. The disk-shaped insulator 32 is disposed between the base 23 and the disk-shaped bottom plate 26.

  The annular upper electrode 27 and the annular lower electrode 29 may be made of, for example, a metal material having heat resistance such as stainless steel, or light aluminum having good electrical conductivity. The insulating material constituting the columnar spacer 30 and the disk-shaped insulator 32 is preferably a material having high strength, low high-frequency loss, high withstand voltage, and high heat resistance, such as fluorine resin such as Teflon (registered trademark), alumina, etc. However, the ceramics are not limited to this because of cost.

  The base 23, the disk-shaped insulator 32 and the disk-shaped bottom plate 26 move up and down integrally with the cylindrical body 25 by a pusher (not shown), and the annular lower electrode 29 of the cylindrical body 25. Open and close the bottom.

  The annular conductive member 33 is placed on the upper surface of the cylindrical body 25 so that the upper surface of the annular conductive member 33 is flush with the upper flange 21 a of the cylindrical support member 22.

  A gas exhaust pipe 35 having upper and lower flanges 34 a and 34 b is placed on the upper flange 21 a of the support member 22 and the upper surface of the annular insulating member 33. The exhaust pipe 35 is grounded. The gas exhaust pipe 35 is fixed to the support member 22 by screwing screws (not shown) from the lower flange 34 b of the exhaust pipe 35 to the upper flange 21 a of the support member 22. Further, by screwing a screw (not shown) from the lower flange 34b of the gas exhaust pipe 35 through the annular conductive member 33 to an annular upper electrode 27 constituting the cylindrical body 25 and an exterior cylinder (not shown). The tubular body 25 and the exterior tubular body are suspended from the annular conductive member 33 and the gas exhaust pipe 35. When the annular upper electrode 27 of the cylindrical body 25 is suspended from the annular conductive member 33 and the gas exhaust pipe 35, the annular upper electrode 27 and the gas exhaust pipe 35 are electrically completely connected by screws. The mounting structure is conductive, and the annular upper electrode 27 is completely grounded. On the other hand, the annular lower electrode 29 which is a high frequency application electrode is insulated in high frequency from the annular upper electrode 27 which is grounded by an annular insulator 28 which is thick in the vertical direction and has high impedance in high frequency. .

  The branch gas exhaust pipe 36 is connected to the side wall of the gas exhaust pipe 35, and an exhaust facility such as a vacuum pump (not shown) is attached to the other end. The grounded lid 37 is airtightly fixed to the upper flange 34 a of the gas exhaust pipe 35. Further, the conductive honeycomb member 38 is fixed on the cylindrical spacer 30 and the upper end portion of the plastic bottle B so as to come into contact with the exhaust pipe 35 and to be grounded.

  The high frequency power supply 39 is connected to the annular lower electrode 29 constituting the cylindrical body 25 through a cable 40 and a power supply terminal (not shown). The matching unit 41 is interposed in the cable 40.

  The gas supply pipe 42 passes through the lid 37, is inserted into the gas exhaust pipe 35 in the vicinity of the mouth of the plastic bottle B stored in the storage member 24, and further passes through the conductive honeycomb member 38. ing. The gas supply pipe 42 is of an attachment type so that the length and material can be changed, and can be selectively used depending on the coating conditions. When the gas supply pipe 42 is inserted from the mouth of the plastic bottle B to the vicinity of the bottom thereof, the gas supply pipe portion 43 located in the plastic bottle B is used as an insulator as indicated by a broken line.

  Next, a method for producing an inner surface carbon film-coated plastic container will be described using the barrier film forming apparatus shown in FIG.

  The base 23, the disk-shaped insulator 32 and the disk-shaped bottom plate 26 are removed by a pusher (not shown) to open the bottom of the annular lower electrode 29 of the cylindrical body 25. Subsequently, after a plastic container, for example, a plastic bottle B is inserted into the bottom of the lower electrode 29 opened from the mouth side, the disc-shaped bottom plate 26 and the disc-like shape are placed on the bottom side of the cylindrical body 25 by a pusher (not shown). By attaching the insulator 32 and the base 23 in this order, the plastic bottle B is accommodated in the cylindrical body 25, the columnar spacer 30, and the disc-shaped bottom plate 26 as shown in FIG.

  Next, gas inside and outside the gas exhaust pipe 35 and inside and outside the plastic bottle B is exhausted through the branch exhaust pipe 36 and the gas exhaust pipe 35 by an exhaust system (not shown). Subsequently, a raw material gas, for example, a medium gas is supplied into the inside of the PET bottle B through the gas supply pipe 42. Thereafter, the gas supply amount and the gas exhaust amount are balanced, and the inside of the plastic bottle B is set to a predetermined gas pressure.

  Next, high-frequency power having a frequency of 13.56 MHz, for example, is supplied from the high-frequency power source 39 to the annular lower electrode 29 of the cylindrical body 25 through the cable 40, the matching unit 41, and a power supply terminal (not shown). At this time, a discharge is generated through the base material of the plastic bottle B in the plastic bottle B between the annular lower electrode 29 and the annular upper electrode 27 grounded with the annular insulator 28 interposed therebetween. Due to the generation of such plasma, the medium gas is dissociated by the plasma and the inner surface of the plastic bottle B stored in the storage member 24 is coated with a carbon film.

  The columnar spacer 30 is installed to adjust the electric field at the mouth and shoulder of the plastic bottle B. When it is desired to reduce the thickness of the inner surface of the plastic bottle B, the radial thickness of the cylindrical spacer 30 is increased. Conversely, when the thickness is increased, the thickness is reduced or the cylindrical spacer 27a itself is omitted. The thickness of the mouth can be reduced in order to make it uniform or look good. Of course, if the uniformity can be obtained without the cylindrical spacer 30, the cylindrical spacer 30 does not need to be installed.

  After the thickness of the carbon film reaches a predetermined film thickness, the supply of the high frequency power from the high frequency power supply 39 is stopped, the supply of the medium gas is stopped, the residual gas is exhausted, and the exhaust of the gas is stopped. Then, nitrogen, rare gas, air or the like is supplied into the plastic bottle B through the gas supply pipe 42, the inside and outside of the plastic bottle B is returned to atmospheric pressure, and the inner surface carbon film-coated plastic bottle is taken out. Thereafter, the plastic bottle B is exchanged according to the above-described order, and the next plastic bottle coating operation is started.

  As the medium gas, the same gas as described in the first embodiment can be used.

  The high frequency power is generally 13.56 MHz and 100 to 1000 W, but is not limited to this as described in the first embodiment. Moreover, the application of these electric powers may be continuous or intermittent (pulse-like), and a negative DC pulse having a pulse width of 100 ns or less that functions similarly to a high frequency may be used.

  As described above, according to the second embodiment, plasma is generated in the plastic bottle B stored in the storage member 24 by performing discharge between the annular upper and lower electrodes 27 and 29 constituting the cylindrical body 25 of the storage member 24. By generating, the front end (lower end) of the gas supply pipe 42 for supplying the medium gas can be positioned, for example, in the gas exhaust pipe 35 in the vicinity of the mouth of the plastic bottle B stored in the storage member 24. As a result, since the above-described plasma generation and medium gas dissociation can be performed in the state where unnecessary members (internal electrodes) are not present in the PET bottle B as in the prior art, stable supply of medium gas, stable plasma The carbon film having a good film quality and a uniform film thickness can be coated on the inner surface of the PET bottle B. Moreover, the complicated maintenance operation for cleaning the unnecessary member which exists in the plastic bottle B can be eliminated. In addition, since the carbon film can be prevented from being coated on the internal electrode, the coating speed of the carbon film on the inner surface of the PET bottle B can be improved.

  Furthermore, in the first embodiment described above, since the exhaust pipe is a ground electrode, plasma is also generated in the exhaust pipe. For this reason, since the input electric power is also used for generation of unnecessary plasma in the exhaust pipe, the efficiency is lowered. Moreover, since the carbon film is coated on the inner surface of the exhaust pipe, maintenance (cleaning) of this portion is required. In the second embodiment, since the generation of plasma is limited to the inside of the plastic bottle B, such a problem can be avoided.

  Therefore, PET bottles coated with a barrier film such as a carbon film having excellent barrier properties that prevent permeation of oxygen from the outside and carbon dioxide from the inside (for example, carbonated drinking water) are efficiently and mass-produced. be able to.

  Further, the grounded conductive honeycomb member 38 confines the high frequency electric field applied from the annular lower electrode 29 inside the PET bottle B, thereby ensuring the effect that the discharge does not spread into the gas exhaust pipe 35. Due to this effect, discharge occurs only between the annular lower electrode 29 and the annular upper electrode 27 grounded with the annular insulator 28 interposed therebetween. For example, when the high frequency power applied from the annular lower electrode 29 has a low output of about 200 W, the discharge is generated only in the plastic bottle B without the conductive honeycomb member 38. For this reason, the conductive honeycomb member 38 is not necessarily provided. However, it is preferable to provide the conductive honeycomb member 38 when the electric power increases. The conductive honeycomb member 38 has, for example, a honeycomb shape with an opening diameter of about 1 mm to 7 mm so that a high-frequency electric field can be sufficiently blocked, and has an opening ratio of 95% or more so that the exhaust resistance from the PET bottle B is sufficiently small. Is preferred. The material must be conductive, such as stainless steel and aluminum, and is preferably heat resistant because it is exposed to plasma. In place of the honeycomb, a mesh or a wire net can be used instead. Further, the surface may be coated with an insulator. This can be expected to have an effect of reducing an electrical change that occurs when the film adheres to the conductive honeycomb member 38 and an effect of easily cleaning the carbon film.

  The annular lower electrode 29 and the annular upper electrode 27 are formed so that the discharge is a symmetric discharge, the bias voltages generated on the inner surfaces of the PET bottles inside the electrodes are substantially equal, and the same coating quality and coating speed can be obtained on the inner surfaces of both electrodes. The inner surface area in contact with the plastic bottle B (including the columnar spacer 30) is preferably substantially equal. Furthermore, if the surface area ratio is finely adjusted, higher uniformity can be obtained.

  The annular insulator 28 is disposed between the annular lower electrode 29 and the grounded annular upper electrode 27, and there is a possibility that power loss may occur if capacitively coupled. It is preferable that it is sufficiently thick in the height direction of the bottle so that is sufficiently large. However, if the annular insulator 28 is thick, the portion of the PET bottle B that is in contact with the inside of the annular insulator 28 that is not in contact with the metal electrode widens. In this part, no bias voltage is generated, the inflow amount of ion species and the ion energy are low, the film formation speed does not increase, the film quality is deteriorated and the barrier property is lowered, and the metal electrode is not in contact. Narrower portions are preferred.

  For this reason, it is preferable to extend at least one of the annular lower electrode 29 and the annular upper electrode 27 as thin as a metal protrusion 31 between the outer periphery of the plastic bottle B inside the annular insulator 28. For example, if it is 3 mm or less and 1 mm or more, the influence can be ignored in view of the overall barrier properties, which is preferable. Of course, it is necessary not to contact each other. Since the protrusion 31 is thin, there is almost no capacitive coupling, and the high-frequency impedance can be maintained large as described above. On the other hand, a bias voltage can be generated on the inner surface of the plastic bottle B in contact with the protruding portion 31, and a good quality film can be coated at high speed on the inner surface of the plastic bottle B in contact with this portion.

  In the second embodiment, the connection of the high-frequency power source and the ground to each annular electrode may be reversed, that is, the high-frequency power source may be connected to the annular upper electrode of the cylindrical body, and the annular lower electrode of the cylindrical body may be grounded. .

  Also, the annular upper and lower electrodes 27 and 29 constituting the cylindrical body 25 of the storage member 24 can have various sizes, and are not limited to the shape shown in FIG. For example, although the upper electrode 27 has shown the case where the upper end is flush with the upper end of the plastic bottle B, an annular insulating member is disposed in place of the annular conductive member 33 to increase the thickness of the upper electrode 27. If the upper end is lowered to the height of the neck ring part under the mouth of the plastic bottle B, the coating on the mouth of the plastic bottle B can be prevented. As a result, the appearance associated with the coating on the mouth of the plastic bottle B is poor (the coating color is brown), and the commercial value of the plastic bottle can be avoided.

(Third embodiment)
The third embodiment has the same configuration as that of the second embodiment shown in FIG. 2 except that the conductive honeycomb member is not installed and the members constituting the exhaust system, that is, the lid and the gas exhaust pipe. This is different from the second embodiment in that the material is an insulating material.

  In the third embodiment, the discharge is confined in the plastic bottle B by the conductive honeycomb member 31 in the second embodiment, but the high-frequency electric field is substantially changed to the exhaust pipe 35 side by making the exhaust part an insulator. It is characterized by suppressing discharge in the exhaust pipe. In the second embodiment, the conductive honeycomb member 31 is coated with a slight film, and if it is too thick, the outflow of gas is hindered. Therefore, in the third embodiment, there is no such member. There is no need.

  The material of the lid 37 and the gas exhaust pipe 35 is preferably an insulator as a whole, but the outside may be a metal if the inner surface is an insulator. At this time, the insulator on the inner surface has a sufficient thickness of 5 mm or more, preferably 10 mm or more, and the impedance to the high frequency is sufficiently large compared to the impedance of the PET bottle B inside the annular upper electrode 27 to function as a ground electrode, Preferably it is about 10 times or more.

(Fourth embodiment)
FIG. 3 is a sectional view showing an apparatus for forming a barrier film on the inner surface of a plastic container according to the fourth embodiment. In FIG. 3, members similar to those in FIG. 2 referred to in the second embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  In this barrier film forming apparatus, a bias power source 44 is connected to an annular upper electrode 27 constituting the cylindrical body 25 of the housing member 24 through a cable 45 and a power supply terminal 46. The matching unit 47 is interposed in the cable 45 between the bias power supply 44 and the power supply terminal 46. The gas exhaust pipe 35 is grounded.

  The high frequency power supply 48 is connected to the annular lower electrode 29 constituting the cylindrical body 25 through a cable 49 and a power supply terminal (not shown). The matching unit 50 is interposed in the cable 49.

  Next, a method for manufacturing an inner surface carbon film-coated plastic container will be described using the barrier film forming apparatus shown in FIG.

  The base 23, the disk-shaped insulator 32 and the disk-shaped bottom plate 26 are removed by a pusher (not shown) to open the bottom of the annular lower electrode 29 of the cylindrical body 25. Subsequently, after a plastic container, for example, a plastic bottle B is inserted into the bottom of the lower electrode 29 opened from the mouth side, the disc-shaped bottom plate 26 and the disc-like shape are placed on the bottom side of the cylindrical body 25 by a pusher (not shown). By attaching the insulator 32 and the base 23 in this order, the plastic bottle B is accommodated in the cylindrical body 25, the columnar spacer 30, and the disc-shaped bottom plate 26 as shown in FIG.

  Next, gas inside and outside the gas exhaust pipe 35 and inside and outside the plastic bottle B is exhausted through the branch exhaust pipe 36 and the gas exhaust pipe 35 by an exhaust system (not shown). Subsequently, a raw material gas, for example, a medium gas is supplied into the inside of the PET bottle B through the gas supply pipe 42. Thereafter, the gas supply amount and the gas exhaust amount are balanced, and the inside of the plastic bottle B is set to a predetermined gas pressure.

  Next, bias power is supplied from the bias power source 44 to the annular upper electrode 27 of the cylindrical body 25 through the cable 45, the matching unit 47 and the power supply terminal 46. Thereafter, or at the same time, high-frequency power is supplied from the high-frequency power source 48 to the annular lower electrode 29 of the cylindrical body 25 through the cable 49, the matching unit 50, and a power supply terminal (not shown). At this time, plasma is generated between the annular lower electrode 29 and the annular upper electrode 27 disposed with the annular insulator 28 sandwiched between the annular lower electrode 29. Further, since the exhaust pipe 35 located above the annular upper electrode 27 is grounded, a bias voltage is generated from the upper electrode 27 toward the annular lower electrode 29 with the exhaust pipe 35 as a reference potential, that is, generated. Can be applied toward the plasma.

  As a result, a) When high-frequency power is used, a higher electron density than that of high-frequency power can be obtained particularly under low gas pressure conditions, so that the collision frequency with the medium gas increases and the film-forming seed density can be increased. B) By adjusting the bias power, the potential difference from the plasma potential can be made variable, so that the ion energy incident on the inner surface of the PET bottle B can be adjusted. C) The ion density is proportional to the electron density. Thus, the ion flux incident on the inner surface of the plastic bottle B can be controlled. The film-forming species obtained when the medium gas is dissociated by the plasma by drawing the plasma into the annular upper electrode 27 by generating the plasma and applying the bias voltage to the annular upper electrode 27 is the storage member 24. It can be efficiently incident on the inner surface of the plastic bottle B.

  After the thickness of the carbon film reaches a predetermined film thickness, supply of bias power and high frequency power from the bias power supply 44 and high frequency power supply 48 is stopped, supply of medium gas is stopped, and residual gas is exhausted. After stopping the gas exhaust, nitrogen, rare gas, air or the like is supplied from the gas supply pipe 42 into the PET bottle B, and the inside and outside of the PET bottle B is returned to the atmospheric pressure, and the inner surface carbon film coated PET bottle Take out. Thereafter, the plastic bottle B is exchanged according to the above-described order, and the next plastic bottle coating operation is started.

  As the medium gas, the same gas as described in the first embodiment can be used.

  The high-frequency power is generally defined as 30 to 300 MHz, but is not limited thereto. Moreover, the application of these electric powers may be continuous or intermittent (pulsed).

  The bias power is generally 13.56 MHz and 100 to 1000 W, but is not limited thereto. Further, the bias power may be applied continuously or intermittently (pulsed).

  As described above, according to the fourth embodiment, plasma is generated in the plastic bottle B stored in the storage member 24 by discharging between the annular upper and lower electrodes 27 and 29 constituting the cylindrical body 25 of the storage member 24. By generating, the tip (lower end) of the gas supply pipe 39 for supplying the medium gas can be positioned in the gas exhaust pipe 35 in the vicinity of the mouth of the plastic bottle B stored in the storage member 24, for example. As a result, since the plasma generation and the dissociation of the medium gas can be performed in the state where there is no internal electrode in the PET bottle B as in the prior art, stable plasma generation can be achieved, and the film quality is good. A carbon film having a uniform film thickness can be coated on the inner surface of the PET bottle B. Moreover, the complicated maintenance operation for cleaning the internal electrode which exists in the PET bottle B can be eliminated. In addition, since the carbon film can be prevented from being coated on the internal electrode, the coating speed of the carbon film on the inner surface of the PET bottle B can be improved.

  In addition, a plasma is generated between the annular upper and lower electrodes 27 and 29, and a bias voltage is applied from the annular upper electrode 27 to the annular lower electrode 29 to obtain a product obtained when the medium gas is dissociated by the plasma. Since the film type can be efficiently incident on the inner surface of the PET bottle B, a uniform carbon film having a uniform thickness on the inner surface of the PET bottle B can be coated at a high speed.

  Therefore, an inner surface carbon film-coated PET bottle with excellent barrier properties that prevents the permeation of oxygen from the outside and the permeation of carbon dioxide from the inside (for example, carbonated drinking water) can be produced more mass-produced.

  In the fourth embodiment, the connection of the bias power source and the high frequency power source to each annular electrode is reversed, that is, the bias power source is the cylindrical lower electrode and the high frequency power source is the cylindrical upper electrode. You may connect.

(Fifth embodiment)
FIG. 4 is a cross-sectional view showing a barrier film forming apparatus on the inner surface of a plastic container according to a fifth embodiment, and FIG. 5 is a perspective view showing a cylindrical body of FIG.

  A cylindrical support member 52 having flanges 51 a and 51 b at the upper and lower ends is placed on an annular base 53. A storage member 54 that stores a plastic container (for example, a plastic bottle) B that forms a barrier film is disposed in the cylindrical support member 52 and the annular base 53.

  The storage member 54 includes a cylindrical body 55 having an upper portion that swells inward when the PET bottle B is inserted, and a disc-shaped member made of an insulating material disposed at the bottom of the cylindrical body 55. And a bottom plate 56. As shown in FIG. 5, the cylindrical body 55 is divided into, for example, 24 in the axial direction so that the first electrode pieces 571 and the second electrode pieces 572 are arranged in the circumferential direction with the insulating pieces 58 interposed therebetween. ing. A cylindrical spacer 59 made of an insulating material is disposed on the upper portion of the PET bottle B and the bulging portion inside the upper portion of the cylindrical body 55. An exterior cylindrical body made of an insulating material (not shown) is disposed on the outer periphery of the cylindrical body 55 to prevent a positional shift of the cylindrical body 55 made of each of the divided pieces. The disc-shaped insulator 60 is disposed between the base 53 and the disc-shaped bottom plate 56.

  The first and second electrode pieces 571 and 572 are made of a metal material having heat resistance such as stainless steel, but may be made of aluminum.

  The base 53, the disk-shaped insulator 60, and the disk-shaped bottom plate 56 are integrally moved up and down with respect to the cylindrical body 55 by a pusher (not shown) to open and close the bottom of the cylindrical body 55. .

  The annular insulating member 61 is placed on the upper surface of the cylindrical body 55 such that the upper surface of the annular insulating member 61 is flush with the upper flange 51 a of the cylindrical support member 52.

  A gas exhaust pipe 63 having upper and lower flanges 62 a and 62 b is placed on the upper flange 51 a of the support member 52 and the upper surface of the annular insulating member 61. The exhaust pipe 63 is grounded. The gas exhaust pipe 63 is fixed to the support member 52 by screwing screws (not shown) from the lower flange 62 b of the exhaust pipe 63 to the upper flange 51 a of the support member 52. Further, screws (not shown) penetrate the annular insulating portion 61 from the lower flange 62b of the gas exhaust pipe 63, and each first electrode piece 571, each second electrode piece 572, and each insulating piece constituting the cylindrical body 55. The tubular body 55 and the exterior tubular body are suspended from the annular insulating member 61 and the gas exhaust pipe 63 by being screwed to 58 and an exterior tubular body (not shown). When the cylindrical body 55 is suspended from the annular insulating member 61 and the gas exhaust pipe 63, the first electrode pieces 571, the second electrode pieces 572, and the gas exhaust gas constituting the cylindrical body 55 are used. The mounting structure is such that the pipe 63 and the screw are not electrically connected. The branch gas exhaust pipe 64 is connected to the side wall of the gas exhaust pipe 63, and an exhaust facility such as a vacuum pump (not shown) is attached to the other end. The grounded lid 65 is airtightly fixed to the upper flange 62 a of the gas exhaust pipe 63.

  The high frequency power supply 66 is connected to each first electrode piece 571 constituting the tubular body 55 through a cable 67 and a power supply terminal 68 as shown in FIGS. The matching unit 69 is interposed in the cable 67 between the high-frequency power source 66 and the power feeding terminal 68. Each of the second electrode pieces 572 constituting the cylindrical body 55 is grounded.

  The gas supply pipe 70 passes through the lid body 65 and is inserted into the gas exhaust pipe 63 in the vicinity of the mouth of the plastic bottle B stored in the storage member 54.

  Next, a method for producing an inner surface carbon film-coated plastic container will be described using the barrier film forming apparatus shown in FIG.

  The base 53, the disk-shaped insulator 60 and the disk-shaped bottom plate 56 are removed by a pusher (not shown) to open the bottom of the cylindrical body 55. Subsequently, after a plastic container, for example, a plastic bottle B is inserted into the bottom of the cylindrical body 55 opened from the mouth side, the disk-shaped bottom plate 56 and the disc are placed on the bottom of the cylindrical body 55 by a pusher (not shown). By attaching the cylindrical insulator 59 and the base 53 in this order, the plastic bottle B is accommodated in the cylindrical body 55, the columnar spacer 59, and the disc-shaped bottom plate 56 as shown in FIG.

  Subsequently, the gas inside the gas exhaust pipe 63 and the inside and outside of the PET bottle B are exhausted through the branch exhaust pipe 64 and the gas exhaust pipe 63 by an exhaust equipment (not shown). Subsequently, a raw material gas, for example, a medium gas is supplied into the inside of the plastic bottle B through the gas supply pipe 70. Thereafter, the gas supply amount and the gas exhaust amount are balanced, and the inside of the plastic bottle B is set to a predetermined gas pressure.

  Next, high-frequency power having a frequency of 13.56 MHz, for example, is supplied from the high-frequency power source 66 to each first electrode piece 571 of the cylindrical body 55 through the cable 67, the matching unit 69 and the power supply terminal 68. At this time, the first electrode pieces 571 are arranged with the insulating pieces 58 sandwiched between the grounded second electrode pieces 572, so that the first electrode pieces 571 and the second electrode pieces 572 are interposed therebetween. Plasma is generated. That is, uniform plasma is generated throughout the height direction and the circumferential direction in the plastic bottle B. Due to the generation of such plasma, the medium gas is dissociated by the plasma and the inner surface of the plastic bottle B stored in the storage member 54 is coated with a carbon film. The columnar spacers 58 installed at the mouth and shoulder of the plastic bottle B have a function of adjusting the electric field at the mouth and shoulder of the plastic bottle B as in the first to fourth embodiments.

  After the thickness of the carbon film reaches a predetermined thickness, the supply of the high frequency power from the high frequency power supply 66 is stopped, the supply of the medium gas is stopped, the residual gas is exhausted, and the exhaust of the gas is stopped. Then, nitrogen, rare gas, air, or the like is supplied into the PET bottle B through the gas supply pipe 70, the inside and outside of the PET bottle B are returned to atmospheric pressure, and the inner surface carbon film coated PET bottle is taken out. Thereafter, the plastic bottle B is exchanged according to the above-described order, and the next plastic bottle coating operation is started.

  As the medium gas, the same gas as described in the first embodiment can be used.

  The high frequency power is generally 13.56 MHz and 100 to 1000 W, but is not limited thereto. Moreover, the application of these electric powers may be continuous or intermittent (pulsed).

  As described above, according to the fifth embodiment, the pet stored in the storage member 54 is discharged between the first electrode piece 571 and the second electrode piece 572 constituting the cylindrical body 55 of the storage member 54. By generating plasma in the bottle B, the tip (lower end) of the gas supply pipe 70 for supplying the medium gas is connected to, for example, the gas exhaust pipe 63 near the mouth of the plastic bottle B stored in the storage member 54. Can be positioned. As a result, since the plasma generation and the dissociation of the medium gas can be performed in the state where there is no internal electrode in the PET bottle B as in the prior art, stable plasma generation can be achieved, and the film quality is good. A carbon film having a uniform film thickness can be coated on the inner surface of the PET bottle B. Moreover, the complicated maintenance operation for cleaning the internal electrode which exists in the PET bottle B can be eliminated. In addition, since the carbon film can be prevented from being coated on the internal electrode, the coating speed of the carbon film on the inner surface of the PET bottle B can be improved.

  Further, as shown in FIG. 5, the cylindrical body 55 is divided into, for example, 24 in the circumferential direction so that the first electrode pieces 571 and the second electrode pieces 572 are arranged with the insulating pieces 58 interposed therebetween in the circumferential direction. The first electrode piece 571 and the second electrode piece are arranged by supplying the high-frequency power from the high-frequency power source 66 to the first electrode pieces 571 which are arranged with the grounded second electrode pieces 572 and the insulating pieces 58 interposed therebetween. 572 can be generated, that is, uniform plasma can be generated in the whole height direction and circumferential direction in the plastic bottle B accommodated in the cylindrical body 55. A carbon film having a uniform thickness can be coated on the inner surface.

  Therefore, the inner surface carbon film-coated PET bottle having excellent barrier properties that prevents the permeation of oxygen from the outside and the permeation of carbon dioxide from the inside (for example, carbonated drinking water) can be mass-produced.

(Sixth embodiment)
FIG. 6 is a cross-sectional view showing a barrier film forming apparatus on the inner surface of a plastic container according to the sixth embodiment, and FIG. 7 is a perspective view showing a cylindrical body of FIG. In FIG. 6, the same members as in FIG. 4 referred to in the fifth embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In this barrier film forming apparatus, a bias power source 71 is connected to each first electrode piece 571 constituting the cylindrical body 55 through a cable 72 and a power supply terminal 73 as shown in FIGS. The matching unit 74 is interposed in the cable 72 between the bias power supply 71 and the power supply terminal 73. The gas exhaust pipe 63 is grounded.

  As shown in FIG. 7, the high-frequency power source 75 is connected to each second electrode piece 572 constituting the cylindrical body 55 through a cable 76 and a power supply terminal (not shown). The matching unit 77 is interposed in the cable 76.

  Next, a method for producing an inner surface carbon film-coated plastic container will be described using the barrier film forming apparatus shown in FIG.

  The base 53, the disk-shaped insulator 60 and the disk-shaped bottom plate 56 are removed by a pusher (not shown) to open the bottom of the cylindrical body 55. Subsequently, after a plastic container, for example, a plastic bottle B is inserted into the bottom of the cylindrical body 55 opened from the mouth side, the disk-shaped bottom plate 56 and the disc are placed on the bottom of the cylindrical body 55 by a pusher (not shown). By attaching the cylindrical insulator 60 and the base 53 in this order, the plastic bottle B is accommodated in the cylindrical body 55, the cylindrical spacer 59, and the disc-shaped bottom plate 56 as shown in FIG.

  Subsequently, the gas inside the gas exhaust pipe 63 and the inside and outside of the PET bottle B are exhausted through the branch exhaust pipe 64 and the gas exhaust pipe 63 by an exhaust equipment (not shown). Subsequently, a raw material gas, for example, a medium gas is supplied into the inside of the plastic bottle B through the gas supply pipe 70. Thereafter, the gas supply amount and the gas exhaust amount are balanced, and the inside of the plastic bottle B is set to a predetermined gas pressure.

  Next, bias power is supplied from the bias power source 71 to the first electrode piece 571 of the cylindrical body 55 through the cable 72, the matching unit 74 and the power supply terminal 73. Thereafter, or simultaneously, high-frequency power is supplied from the high-frequency power source 75 to the second electrode piece 572 of the cylindrical body 55 through the cable 76, the matching unit 77, and a power supply terminal (not shown). At this time, plasma is generated between the first electrode pieces 571 and the second electrode pieces 572 arranged with the insulating pieces 58 interposed between the first electrode pieces 571. Further, since the exhaust pipe 63 located above the cylindrical body 55 is grounded, a bias voltage is directed from the first electrode pieces 571 toward the second electrode pieces 572 with the exhaust pipe 63 as a reference potential. In other words, it can be applied toward the generated plasma. The columnar spacer 59 installed at the mouth and shoulder of the plastic bottle B has a function of adjusting the electric field at the mouth and shoulder of the plastic bottle B as in the first to fifth embodiments.

  As a result, a) When high-frequency power is used, a higher electron density than that of high-frequency power can be obtained particularly under low gas pressure conditions, so that the collision frequency with the medium gas increases and the film-forming seed density can be increased. By adjusting the bias power, the potential difference from the plasma potential can be made variable, so that the ion energy incident on the inner surface of the PET bottle B can be adjusted. C) The ion density is proportional to the electron density. Thus, the ion flux incident on the inner surface of the plastic bottle B can be controlled. A film-forming type obtained when the medium gas is dissociated by the plasma by drawing the plasma into the first electrode pieces 571 by generating the plasma and applying a bias voltage to the first electrode pieces 571. Can be efficiently incident on the inner surface of the plastic bottle B in the storage member 54.

  After the thickness of the carbon film reaches a predetermined film thickness, supply of bias power and high frequency power from the bias power source 71 and high frequency power source 75 is stopped, supply of medium gas is stopped, and residual gas is exhausted. After stopping the gas exhaust, nitrogen, rare gas, air or the like is supplied from the gas supply pipe 70 into the PET bottle B, and the inside and outside of the PET bottle B is returned to the atmospheric pressure, and the inner surface carbon film coated PET bottle Take out. Thereafter, the plastic bottle B is exchanged according to the above-described order, and the next plastic bottle coating operation is started.

  As the medium gas, the same gas as described in the first embodiment can be used.

  The high-frequency power is generally defined as 30 to 300 MHz, but is not limited thereto. Moreover, the application of these electric powers may be continuous or intermittent (pulsed).

  The bias power is generally 13.56 MHz and 100 to 1000 W, but is not limited thereto. Further, the bias power may be applied continuously or intermittently (pulsed).

  As described above, according to the sixth embodiment, the pet stored in the storage member 54 is discharged between the first electrode piece 571 and the second electrode piece 572 constituting the cylindrical body 55 of the storage member 54. By generating plasma in the bottle B, the tip (lower end) of the gas supply pipe 70 for supplying the medium gas is connected to, for example, the gas exhaust pipe 63 near the mouth of the plastic bottle B stored in the storage member 54. Can be positioned. As a result, since the plasma generation and the dissociation of the medium gas can be performed in the state where there is no internal electrode in the PET bottle B as in the prior art, stable plasma generation can be achieved, and the film quality is good. A carbon film having a uniform film thickness can be coated on the inner surface of the PET bottle B. Moreover, the complicated maintenance operation for cleaning the internal electrode which exists in the PET bottle B can be eliminated. In addition, since the carbon film can be prevented from being coated on the internal electrode, the coating speed of the carbon film on the inner surface of the PET bottle B can be improved.

  Further, as shown in FIG. 7, the cylindrical body 55 is divided into, for example, 24 in the circumferential direction so that the first electrode pieces 571 and the second electrode pieces 572 are arranged with the insulating pieces 58 interposed therebetween in the circumferential direction. By supplying bias power and high-frequency power to the first electrode pieces 571 and the second electrode pieces 572 arranged with the insulating pieces 58 in between, the first electrode pieces 571 and the second electrode pieces 572 Plasma can be generated during this period, that is, uniform plasma can be generated in the whole height direction and circumferential direction in the plastic bottle B accommodated in the cylindrical body 55, A carbon film having a uniform thickness can be coated.

  Further, plasma is generated between the first electrode pieces 571 and the second electrode pieces 572, and a bias voltage is applied from the first electrode pieces 571 toward the second electrode pieces 572. Thus, the film-forming species obtained when the medium gas is dissociated with the plasma can be efficiently incident on the inner surface of the PET bottle B, so that a uniform carbon film with a uniform thickness on the inner surface of the PET bottle B is coated at a high speed. be able to.

  Therefore, an inner surface carbon film-coated PET bottle excellent in barrier properties that prevents permeation of oxygen from the outside and carbon dioxide from the inside (for example, carbonated drinking water) can be mass-produced.

  In the first to sixth embodiments, the coating of the carbon film has been described as an example. However, other barrier films such as SiOx other than the carbon film can be coated by the same operation. For example, in the case of SiOx, the raw material gas can be used by mixing an organic Si compound such as hexamethyldisiloxane (HMDSO) or tetraethoxysilane (TEOS) and oxygen gas.

  Moreover, in 1st-6th embodiment, although the cross-sectional shape of the processed plastic bottle B demonstrated circular object, it is applicable not only to circular but various shapes, such as a rectangle and a hexagon, similarly. It was confirmed. Moreover, although PET was taken as an example of the material of the plastic container, the present invention can be similarly applied to other plastics.

  In the description of the first to sixth embodiments, the term “annular” does not mean only a circular shape but an arbitrary shape having a hollow portion inside. For example, the annular electrode may be any shape that surrounds the outer periphery of the bottle, regardless of whether the shape of the cavity is square or hexagonal. For example, if the cross-sectional shape of the target bottle is a square, it is preferable that the hollow shape is a quadrangle because a uniform electric field can be obtained and a uniform film can be coated.

  In the fourth to sixth embodiments, the tip (lower end) of the gas supply pipe is positioned in the gas exhaust pipe in the vicinity of the mouth of the PET bottle. You may insert from a mouth part to the bottom vicinity. In this case, it is preferable that the gas supply pipe part located in the plastic bottle B is an insulator.

Sectional drawing which shows the barrier film forming apparatus to the inner surface of the plastic container which concerns on 1st Embodiment of this invention. Sectional drawing which shows the barrier film formation apparatus to the inner surface of the plastic container which concerns on 2nd Embodiment of this invention. Sectional drawing which shows the barrier film forming apparatus to the inner surface of the plastic container which concerns on 4th Embodiment of this invention. Sectional drawing which shows the barrier film forming apparatus to the inner surface of the plastic container which concerns on 5th Embodiment of this invention. The perspective view which shows the cylindrical body of FIG. Sectional drawing which shows the barrier film forming apparatus to the inner surface of the plastic container which concerns on 6th Embodiment of this invention. The perspective view which shows the cylindrical body of FIG. Sectional drawing which shows the barrier film forming apparatus to the inner surface of the conventional plastic container.

Explanation of symbols

  2, 22, 52 ... support member, 4 ... external electrode body, 5 ... external electrode bottom member, 6 ... external electrode, 7, 30, 59 ... cylindrical spacer, 11, 35, 63 ... exhaust pipe, 14, 39, 66 ... high frequency power supply, 18, 42, 70 ... gas supply pipe, 24, 54 ... storage member, 25, 55 ... cylindrical body, 27 ... first annular electrode (annular upper electrode), 28 ... annular insulator, 29 ... Second annular electrode (annular lower electrode), 44, 71 ... bias power source, 48, 75 ... high frequency power source, 571 ... first electrode piece, 572 ... second electrode piece, 58 ... insulating piece, B ... PET bottle.

Claims (8)

An external electrode surrounding the container when the plastic container to be processed is inserted;
An exhaust pipe attached to the end face of the external electrode on the side where the mouth of the container is located via an insulating member, and grounded;
An exhaust means for exhausting the gas in the plastic container inserted into the external electrode through the exhaust pipe;
Gas supply means for supplying a raw material gas to the plastic container inserted into the external electrode;
A high frequency power source connected to the external electrode,
An apparatus for forming a barrier film on an inner surface of a plastic container, wherein the conductive member having a gas flow hole is provided in the exhaust pipe in contact with the inner surface of the exhaust pipe.   The apparatus for forming a barrier film on the inner surface of a plastic container according to claim 1, wherein the conductive member has a honeycomb shape.   The apparatus for forming a barrier film on the inner surface of a plastic container according to claim 2, wherein the honeycomb-shaped conductive member has a gas flow hole having a size of 1 to 7 mm.   The barrier film forming apparatus for an inner surface of a plastic container according to claim 2, wherein the honeycomb-shaped conductive member has an opening ratio of 95% or more.   2. The apparatus for forming a barrier film on the inner surface of a plastic container according to claim 1, wherein the conductive member is a mesh or a wire mesh.   6. The apparatus for forming a barrier film on the inner surface of a plastic container according to claim 1, wherein the conductive member is stainless steel or aluminum.   6. The apparatus for forming a barrier film on the inner surface of a plastic container according to claim 1, wherein the surface of the conductive member is coated with an insulating material. In manufacturing the inner surface barrier film-coated plastic container using the barrier film forming apparatus according to claim 1,
(A) inserting a plastic container as an object to be processed into the external electrode;
(B) after exhausting the gas in the container through an exhaust pipe by an exhaust means, supplying a raw material gas into the plastic container by a gas supply means, and setting the plastic container to a predetermined gas pressure;
(C) A high-frequency power is supplied from a high-frequency power source to the external electrode, and a high-frequency electric field is confined in the container-side space from the conductive member by a conductive member, and plasma generation is regulated in the space. Dissociating and coating the inner surface of the plastic container with a barrier film.

Images