JP4105600B2 - Manufacturing method of resin container - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a resin container, more particularly to a method of manufacturing a resin container having a biodegradability.
[0002]
[Prior art]
Conventionally, glass bottles have been used as containers for cosmetics and the like. This utilizes the fact that glass is excellent in gas barrier properties. However, glass bottles are apt to break and have the problem of weight. For this reason, resin containers have been used instead of glass bottles.
[0003]
On the other hand, in recent years, environmental problems related to waste and resource saving have been highlighted, and along with this, there is a technology for giving resin containers properties (biodegradability) that can be decomposed by microorganisms. Attention has been paid. Polylactic acid is known as this biodegradable material, and there is a resin container using this polylactic acid (see Patent Document 1).
[0004]
Since the resin container made of polylactic acid is decomposed by microorganisms, even if it is disposed of in nature, the container is completely disintegrated and decomposed by microorganisms, so that environmental problems do not occur.
[0005]
[Patent Document 1]
JP-A-2001-225430 [0006]
[Problems to be solved by the invention]
As described above, since the resin container formed of polylactic acid is biodegradable, it exhibits good characteristics from the environmental viewpoint. However, since polylactic acid has poor barrier properties, when the content is filled in a resin container made of polylactic acid, there is a problem that the moisture of the content leaks through the resin container over time.
[0007]
Specifically, when a resin container made of polylactic acid and having a capacity of 150 milliliters was filled with water and the decrease in the water was measured, a decrease in water of 24% occurred at room temperature for 3 years. As described above, when the barrier property of the resin container is low, for example, when the cosmetic is used as a content, there is a problem that the remaining cosmetic is deteriorated due to leakage of moisture.
[0008]
The present invention has been made in view of the above, and an object thereof is to provide a method for manufacturing a resin container capable of realizing both biodegradable and barrier properties.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is characterized by the following measures.
[0018]
The invention according to claim 1
A method for producing a resin container in which a carbon film is formed on the inner surface of a container body made of polylactic acid,
Supplying a source gas mainly composed of acetylene gas into the container body,
The acetylene is decomposed into plasma by microwave irradiation, and a carbon film containing a bond with hydrogen is formed by plasma chemical vapor deposition.
[0019]
According to the above invention, a good quality carbon film can be easily formed by supplying the source gas into the container body and performing chemical vapor deposition even on the inner surface of the container body.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 is a cross-sectional view showing a resin container 10 according to an embodiment of the present invention. The resin container 10 includes a container body 11 and a carbon film 12 including a bond between hydrogen. The container body 11 is made of polylactic acid, which is an aliphatic polyester.
[0022]
Polylactic acid has the property of being degraded by microorganisms. For this reason, even if the resin container 10 is disposed of in nature, the resin container 10 is completely disintegrated and decomposed by microorganisms, so that environmental problems do not occur. However, in a resin container consisting only of the resin container 10, polylactic acid has low barrier properties, so that the contents are altered as described above.
[0023]
Therefore, the resin container 10 according to the present embodiment is characterized in that a carbon film formed on the inner surface of the container body 11 is formed. In particular, in the present embodiment, as described later, a chemical vapor deposition method (CVD method) is used to form a carbon film 12 containing a bond with hydrogen as a carbon film (a film containing amorphous carbon is also possible). .
[0024]
In this embodiment, the carbon film 12 including a bond with hydrogen is formed with a thickness of 0.15 μm. However, the thickness of the carbon film 12 including a bond with hydrogen is not limited to this, and can be selected in the range of 0.03 μm to 0.2 μm. If the thickness of the carbon film 12 including a bond with hydrogen is less than 0.03 μm, the barrier property of the resin container 10 cannot be maintained.
[0025]
When the thickness of the carbon film 12 including the bond with hydrogen exceeds 0.2 μm, the carbon film 12 including the bond with hydrogen has a distinctive color (yellowish brown), and the range of use as a container is limited. It will be limited. Further, even when the thickness of the carbon film 12 including the bond with hydrogen exceeds 0.2 μm, the barrier property of the carbon film 12 including the bond with hydrogen is not so different from that when the thickness is 0.2 μm. For this reason, there is no practical benefit even if the thickness of the carbon film 12 including the bond with hydrogen exceeds 0.2 μm.
[0026]
On the other hand, the carbon film 12 including a bond with hydrogen applied in this example has a higher barrier property than other carbon films, and has chemical stability, thermal stability, and stability to a solvent. high. For this reason, when the contents are filled in the resin container 10, even if the container body 11 is formed of polylactic acid having a low barrier property, the vaporized contents of the contents permeate the resin container 10 and leak to the outside. Can be reliably prevented. As a result, it is possible to reliably prevent alteration of the contents filled in the resin container 10.
[0027]
Further, since the carbon film 12 including the bond with hydrogen has various stability as described above, even if the carbon film 12 including the bond with hydrogen is formed on the inner surface of the container body 11, the bond with the hydrogen is not caused. The contained carbon film 12 and the contents do not react. Accordingly, it is possible to prevent the contents filled in the resin container 10 from being altered.
[0028]
FIG. 3 shows the effect of the resin container 10 according to the present embodiment (shown as the embodiment in FIG. 3), compared with the conventional resin container (resin container not provided with the carbon film 12 including a bond with hydrogen. FIG. FIG.
[0029]
The specific experimental conditions of the experimental results shown in the figure are as follows. That is, both the examples and the comparative examples are resin containers having a capacity of 150 milliliters, and the resin containers according to the examples and comparative examples are each filled with 150 g of water and closed with a polypropylene stopper. And this was left to stand for 1 month in each environment of room temperature, 37 degreeC, and 50 degreeC, respectively, and the weight change of the content before and after leaving was calculated | required by the weight change rate. As the resin container 10 according to the example, a carbon film 12 including a bond with hydrogen having a film thickness of 0.15 μm was used.
[0030]
From FIG. 3, it can be seen that the weight change rate of the resin container 10 according to the example is about half the value of the weight change rate of the comparative example which is a conventional resin container in any temperature condition. Therefore, from the results shown in FIG. 3, it was proved that the resin container 10 according to the present example can realize a higher barrier property than the comparative example.
[0031]
Then, the manufacturing method of above-described resin container 10 is demonstrated.
In order to manufacture the resin container 10, first, a process of manufacturing the container body 11 is performed, and then a process of forming a carbon film 12 including a bond with hydrogen on the inner wall of the container body 11 is performed. The container body 11 is made of polylactic acid as a raw material, and is molded into a predetermined shape using an injection blow molding method. As polylactic acid to be used, for example, 4031DK manufactured by Unitika Ltd. can be used.
[0032]
The container body 11 molded as described above is subsequently attached to the resin container manufacturing apparatus 20 shown in FIG. 2, and the formation process of the carbon film 12 including bonding with hydrogen is performed. Here, the configuration of the resin container manufacturing apparatus 20 will be described.
[0033]
The resin container manufacturing apparatus 20 is a plasma CVD apparatus, and performs a process of forming a carbon film 12 including a bond with hydrogen on the inner wall of the resin container 10 to be mounted using a chemical vapor deposition method. In short, the resin container manufacturing apparatus 20 includes a container mounting chamber 21, an exhaust chamber 22, a gas introduction pipe 23, a microwave generator 34, a raw material gas supply device 35, and the like.
[0034]
The container mounting chamber 21 is configured to have the resin container 10 mounted therein. A microwave generator 34 for generating microwaves is disposed on the side wall of the container mounting chamber 21.
[0035]
An exhaust chamber 22 is provided in the upper part of the container mounting chamber 21. The exhaust chamber 22 and the container mounting chamber 21 are configured to be airtightly defined by a partition wall 33. The partition wall 33 is configured to be detachable from the container mounting chamber 21, and is configured to be detachable from the exhaust chamber 22.
[0036]
A first seal member 36 is provided at a substantially central position of the partition wall 33. The first seal member 36 is fixed to the partition wall 33 in a state where the opening 13 of the container body 11 is sealed with respect to the container mounting chamber 21. That is, the opening 13 of the container body 11 is configured to open only to the exhaust chamber 22.
[0037]
The exhaust chamber 22 has an exhaust hole 24 formed on the side thereof. The exhaust hole 24 is connected to a vacuum device (not shown). Therefore, the exhaust chamber 22 is decompressed to a predetermined degree of vacuum by being sucked by the vacuum device. In the present embodiment, the pressure in the exhaust chamber 22 is configured to be 10 Pa in a state where a later-described raw material gas is supplied.
[0038]
A hole 25 is formed in the top plate portion 22 a of the exhaust chamber 22, and a gas introduction pipe 23 is inserted into the hole 25. Further, the second seal member 37 is provided in the hole 25, and thus the exhaust chamber 22 is configured to maintain an airtight state with respect to the outside even when the gas introduction pipe 23 is inserted through the hole 25. Yes.
[0039]
The gas introduction pipe 23 has a configuration in which one end (hereinafter referred to as a lower end portion) is inserted from the opening 13 into the container body 11. That is, the lower end portion of the gas introduction pipe 23 is configured to open to the inside of the container body 11. On the other hand, the other end portion (hereinafter referred to as the upper end portion) of the gas introduction pipe 23 is connected to the source gas supply device 35.
[0040]
The source gas supply device 35 supplies source gas to the gas introduction pipe 23. The source gas may be configured such that an inert gas such as Ar is added as a carrier gas and supplied to the gas introduction pipe 23. Further, as the source gas for forming the carbon film 12 including a bond with hydrogen, various hydrocarbons can be used, but acetylene is preferably used. However, the source gas need not be only acetylene gas, and a gas other than acetylene may be added as necessary. Specifically, it is conceivable to add a film modifier (oxidant or reducing agent).
[0041]
The source gas supplied from the source gas supply device 35 and supplied into the container main body 11 from the lower end of the gas introduction pipe 23 is activated as will be described later, and is deposited on the inner wall of the container main body 11 and remains. The gas flows out from the opening 13 into the exhaust chamber 22 and is exhausted from the exhaust hole 24.
[0042]
Next, a method of manufacturing the resin container 10 by forming the carbon film 12 including a bond with hydrogen on the inner wall of the container main body 11 using the resin container manufacturing apparatus 20 having the above configuration will be described. In the following description, it is assumed that the container main body 11 is already mounted in the resin container manufacturing apparatus 20.
[0043]
In order to form the carbon film 12 including a bond with hydrogen, first, a vacuum device (not shown) is activated. Thereby, the inside of the exhaust chamber 22 and the inside of the container main body 11 are evacuated to a predetermined degree of vacuum.
[0044]
When the inside of the exhaust chamber 22 and the inside of the resin container 10 reach a predetermined degree of vacuum (for example, 10 Pa), the raw material gas supply device 35 is activated, and acetylene gas is mainly contained inside the container body 11 via the gas introduction pipe 23. Supply raw material gas. At the same time, the microwave generator 34 is activated to irradiate the microwave toward the raw material gas in the resin container 10.
[0045]
By this microwave irradiation, the acetylene gas is decomposed into plasma. The plasma-activated acetylene gas is recombined on the inner surface of the container body 11 to form a carbon film 12 containing a bond with hydrogen. In this embodiment, the microwave irradiation time from the microwave generator 34 is set to about 3 seconds.
[0046]
The microwave irradiation time correlates with the amount of plasma generated in the container body 11. For this reason, it is necessary to appropriately select the irradiation time according to the film thickness of the carbon film 12 to be formed in the container body 11.
[0047]
When the carbon film 12 including the bond with hydrogen is formed in the container body 11 as described above, and the resin container 10 is manufactured thereby, the vacuum device, the microwave generator 34, and the source gas supply device 35 are Stopped. And the resin container 10 is taken out from the resin container manufacturing apparatus 20 in the state which the pressure in the exhaust chamber 22 returned to atmospheric pressure.
[0048]
As described above, in this embodiment, since plasma chemical vapor deposition is used to form the carbon film 12 including the bond with hydrogen, even the inner surface of the container body 11 includes a bond with good quality hydrogen. The carbon film 12 can be easily and reliably formed. In addition, the formation process (chemical vapor deposition process) of the carbon film 12 including a bond with hydrogen can be performed at a lower temperature than other chemical vapor deposition methods. For this reason, it is possible to prevent the container body 11 from being altered (particularly altered by heat) when the carbon film 12 including a bond with hydrogen is formed.
[0049]
【The invention's effect】
As described above, according to the present invention, a good quality carbon film including a bond with hydrogen can be easily formed by supplying a source gas into the container body and performing chemical vapor deposition even on the inner surface of the container body. can do. In addition, since chemical vapor deposition can be performed at a low temperature, it is possible to prevent the resin container from being altered during chemical vapor deposition.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a resin container according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a resin container manufacturing apparatus used when a resin container manufacturing method according to an embodiment of the present invention is carried out.
FIG. 3 is a diagram for explaining the effect of a resin container according to an embodiment of the present invention, in comparison with a conventional resin container.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Resin container 11 Container main body 12 Carbon film | membrane 20 containing the coupling | bonding with hydrogen Resin container manufacturing apparatus 21 Container mounting chamber 22 Exhaust chamber 23 Gas introduction pipe 24 Exhaust hole 33 Partition 34 Microwave generator 35 Raw material gas supply apparatus

Claims (2)

A method for producing a resin container in which a carbon film is formed on the inner surface of a container body made of polylactic acid,
Supplying a source gas mainly composed of acetylene gas into the container body,
A method for producing a resin container, comprising: decomposing acetylene into plasma by microwave irradiation to form a carbon film containing a bond with hydrogen using a plasma chemical vapor deposition method.   The resin container according to claim 1,
  The thickness of the carbon film including the bond with hydrogen 0.03 μm or more 0.2 The manufacturing method of the resin container characterized by being referred to as micrometer or less.

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