JP2000255579A - Plastic container and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the barrier property, transparency, impact-resistance and flexibility or the like by forming a barrier layer wherein the carbon content or the like is changed during one film forming by a plasma CVD method using a gas having a vaporized organic silicon compound, and a gas having an oxida tion function in a plasma or the like. SOLUTION: By using a gas having at least an organic silicon compound and oxygen or a gas having an oxidation function, a barrier layer containing a silicon compound, and at least one kind of compound comprising one or more kinds of elements from among carbon, hydrogen, silicon and oxygen, is formed at least on one side of a plastic container by a plasma CVD method. For example, the plastic container 1 is set in an external electrode 2, and a gas introducing pipe 3 which becomes a grounding 5, and an air discharging port 4 are set. Then, the inside and the outside of the plastic container 1 are vacuumized, and a required gas or the like is made to flow from the gas introducing pipe 3, and at the same time, a high frequency is applied to the external electrode 2, and a plasma is generated, and a film forming is performed on the internal surface of the plastic container 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plastic container provided with a gas barrier film, and relates to a method and a container for manufacturing a gas barrier plastic container having excellent gas barrier properties, transparency and impact resistance.

[0002]

2. Description of the Related Art In general, plastic containers are widely used as packaging containers in various fields such as foods and pharmaceuticals because of their various characteristics such as ease of molding, light weight, and low cost. It is used.

However, as is well known, plastic has the property of transmitting low molecular gases such as oxygen, carbon dioxide, and water vapor, and the property that low molecular organic compounds are adsorbed inside. Because, having a plastic container, compared to other containers such as glass,
There are various restrictions on the use object and use form.

[0004] For example, when a carbonated beverage such as beer is filled in a plastic container, the content of the beverage is oxidized with time and deteriorates due to oxygen permeating the plastic and penetrating into the container. Moreover, since the carbon dioxide gas of the carbonated beverage permeates the plastic and is released to the outside of the container, the carbonated beverage becomes a drank beverage.

In addition, when a beverage having an aromatic component such as orange juice is filled in a plastic container, an aromatic component which is a low molecular organic compound (for example, limonene of orange juice) contained in the beverage is adsorbed on the plastic. There is a possibility that the composition of the aroma component of the beverage may be out of balance and the quality of the beverage may be degraded.

[0006] Further, when powder of instant coffee or the like is stored in a plastic container, there is a possibility that the quality of the contents may be degraded due to water vapor that has permeated the plastic and penetrated into the container.

[0007] In the case of plastic containers, elution of low-molecular compounds contained in the composition may be a problem. That is, when a plastic container is filled with contents (especially liquid) that require purity, the plasticizer, residual monomer, and other additives contained in the plastic composition are eluted into the contents, and the purity of the contents is increased. May be impaired.

[0008] On the other hand, the collection of used containers has become a social problem and the recycling of resources is being promoted. After that, if left in the environment until recovery, various low-molecular organic compounds such as mold odor adsorb to the plastic container during that time.

The adsorbed low-molecular-weight organic compound remains in the plastic even after washing. For this reason, when a plastic container is used as a refill container, the adsorbed low-molecular-weight organic compound gradually dissolves in the content filled as a foreign component, and the quality of the content deteriorates and there is a problem in hygiene.

[0010] For this reason, plastic containers are rarely used as returnable containers.

[0011] In order to suppress the above-mentioned properties of a plastic container that allows the permeation of a low-molecular gas and the property that a low-molecular organic compound is adsorbed inside, the plastic is oriented to improve the crystallinity. A method of laminating thin films of plastic or aluminum with low adsorptivity is also used, but in all cases, while maintaining the characteristics of plastic containers such as transparency and easy disposal, the problems of gas barrier properties and adsorption Not completely resolved.

Here, in recent years, a technique of coating a plastic container using a plasma CVD method has been known, but the method of forming a film on the outer surface of a bottle solves the problem of a low molecular organic compound adsorbed on the inner surface of the container. Therefore, it is particularly desirable to form a film on the inner surface of the bottle.

As an example of coating the inner surface of a bottle by a plasma CVD method, a method using a DLC film has been reported (JP-A-8-53117). This DLC film is an amorphous carbon mainly composed of SP3 and SP2 bonds between carbons, and is a hard carbon film having a very hard, high refractive index and a very smooth morphology.

Further, as an example of the inner surface coating of a plastic container, a coating using a silicon oxide film has been reported.
In this example, a two-layer structure of an organic polymer film and a silicon oxide film is described.

In order to overcome the problems of transparency and DLC film, and of the flexibility of silicon oxide film, we have proposed to coat silicon oxide, carbon, hydrogen, Already-reported films containing compounds containing at least one or two or more elements from silicon and oxygen have been reported. (Japanese Patent Application No. 10-186393)

[0016]

[Problems to be solved by the invention]

However, in the plasma CVD method, it is required to supply a large amount of raw materials and exhaust a large amount of the raw materials. However, a large amount of cost is required to strengthen the exhaust system.

There is also a method of supplying the raw material gas separately to the organic silicon compound and oxygen, but this method has a drawback that the film formation time is increased.

The present invention has been made in view of such circumstances, and has as its object to provide a method for producing a gas-barrier plastic container having excellent barrier properties, transparency, impact resistance, and flexibility. And

[0020]

[Means for Solving the Problems]

In order to achieve the above object, the method and the container for manufacturing a gas barrier plastic container of the present invention reduce the burden on the exhaust system and the reduction of the film formation time by changing the gas concentration during film formation. It is a target thing.

That is, the method for manufacturing a gas barrier plastic container according to the present invention uses a gas having a vaporized organic silicon compound and oxygen or a gas having an oxidizing power in plasma, and a silicon oxide is added to the plastic container by a plasma CVD method. A film containing a compound comprising at least one or two or more elements from among carbon, hydrogen, silicon and oxygen is formed, and by changing the gas concentration, the carbon content and the like in the film can be reduced to one degree. This is to form a changed barrier layer during film formation.

Specifically, in the first aspect of the present invention, at least an organic silicon compound and a gas having oxygen or oxidizing power are used, and silicon oxide, carbon, hydrogen, and the like are formed on at least one side of a plastic container by a plasma CVD method. A method for producing a plastic container, characterized in that the concentration of an organosilicon compound changes when forming a barrier layer containing at least one compound of at least one or two or more elements from silicon and oxygen. To provide.

According to a second aspect of the present invention, there is provided a method of manufacturing a plastic container according to the first aspect, wherein the concentration of the organic silicon compound decreases during film formation.

According to a third aspect of the present invention, there is provided a method of manufacturing a plastic container according to the first aspect, wherein the concentration of the organic silicon compound repeatedly decreases and increases during film formation.

According to a fourth aspect of the present invention, at least one of silicon oxide, carbon, hydrogen, silicon and oxygen is formed on a substrate by plasma CVD using at least an organic silicon compound and a gas having oxygen or oxidizing power. It is intended to provide a method for producing a plastic container, wherein the supply of an organosilicon compound is stopped during film formation when forming a barrier layer containing at least one kind of a compound composed of one or more kinds of elements. .

According to a fifth aspect of the present invention, at least one of silicon oxide, carbon, hydrogen, silicon and oxygen is formed on a substrate by plasma CVD using at least an organic silicon compound and a gas having oxygen or oxidizing power. A method for producing a plastic container, wherein the supply of an organosilicon compound is stopped during film formation and the supply is started again when forming a barrier layer containing at least one compound composed of one or more kinds of elements. Is provided.

In the sixth aspect of the present invention, at least one of silicon oxide, carbon, hydrogen, silicon and oxygen is formed on a substrate by plasma CVD using at least an organic silicon compound and a gas having oxygen or oxidizing power. A plastic container characterized in that when forming a barrier layer containing at least one kind of a compound comprising two or more kinds of elements, the supply of the organosilicon compound is stopped in the course of film formation and the supply is started again. Is provided.

According to the invention of claim 7, at least one of silicon oxide, carbon, hydrogen, silicon and oxygen is formed on a substrate by plasma CVD using at least an organic silicon compound and a gas having oxygen or oxidizing power. Wherein the flow rate of the organosilicon compound and the flow rate of the oxygen or oxidizing gas are both changed when forming the barrier layer containing at least one kind of a compound comprising two or more kinds of elements. It is intended to provide a manufacturing method.

According to an eighth aspect of the present invention, there is provided a method for producing a plastic container, wherein the barrier layer according to any one of the first to seventh aspects is provided on the inner surface of the bottle.

According to a ninth aspect of the present invention, there is provided an organic silicon compound comprising at least one side containing silicon oxide and at least one compound of at least one or two or more elements selected from carbon, hydrogen, silicon and oxygen. An object of the present invention is to provide a plastic container having a plasma CVD barrier layer in which the concentration of a compound changes.

According to a tenth aspect of the present invention, the concentration of the organosilicon compound decreases during the film formation.
And a plastic container described in (1).

According to an eleventh aspect of the present invention, there is provided a plastic container according to the ninth aspect, wherein the concentration of the organic silicon compound repeatedly decreases and increases during film formation.

According to a twelfth aspect of the present invention, there is provided a plastic container according to the ninth aspect, wherein both the concentration of the organic silicon compound and the oxygen concentration change in the thickness direction.

According to the thirteenth aspect, in the ninth to twelfth aspects,
Wherein the barrier layer is provided on the inner surface of the bottle.

The organic silicon compound constituting the silicon oxide layer is 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, vinyltrimethylsilane, methyltrimethoxysilane, hexamethyldisilane, methylsilane, dimethylsilane. , Trimethylsilane, diethylsilanepropylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, octamethylcyclotetrasiloxane, etc. can do.

Particularly, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane and octamethylcyclotetrasiloxane are preferred.

However, the present invention is not limited to these, and aminosilane, silazane and the like can be used.

The organic silicon compound, which is a liquid, is vaporized, and oxygen or a gas having an oxidizing power (eg, N 2
2O, CO2, etc.), or a raw material gas obtained by mixing the above mixed gas with helium and / or argon as an inert gas, or nitrogen, carbon fluoride, etc., and a plastic container is installed. To form a silicon oxide layer having a thickness of 30-5000Å. Desirably, a film thickness of 100 to 500 ° is desirable from the viewpoint of barrier properties and flexibility.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example will be described below with reference to the drawings. FIG.
As shown in (1), the container is set in the external electrode 2 so as to cover the plastic container 1, and the gas introduction pipe 3 serving as the ground 5 and the exhaust port 4 are set. Next, the inside and outside of the bottle are evacuated using a vacuum pump as shown in FIG. An organic silicon compound and a gas having an oxidizing power are flowed from the gas inlet tube 3, and a high frequency is applied to an external electrode to generate plasma inside the plastic container 1, thereby forming a film on the inner surface. At this time, the concentration of the gas is changed.

Finally, the plastic container 1 was taken out from the external electrode 2, and the product shown in FIG. 1 was completed.

The film is formed on the plastic container by the above method, and the electrode may have a single structure or a combination of plural electrodes. Further, the carbon content in the film can be adjusted by changing the mixing ratio of the introduced organic silicon compound and the gas having oxidizing power, the time, and the high-frequency output.

[0043]

EXAMPLES (Preliminary experiment) Hexamethyldisiloxane (H
MDSO) and the pressure in the chamber when each gas of oxygen flows. The condition 1 is an initial pressure when the HMDSO concentration is changed, the condition 2 is a pressure when the HMDSO concentration is not changed, and the condition 3 is a case where the raw material gas is separately supplied to the organic silicon compound (1) and the oxygen (2). Pressure is also shown. The pressure is measured by Pirani gauge PT
-DB1 was used, and a rotary pump E2M-18 manufactured by EDWARDS and a mechanical booster pump MBS-030 manufactured by ULVAC were used as vacuum pumps.

The condition 4 is obtained by adding the cryopump U10PU manufactured by ULVAC to the exhaust system under the condition 2.

(Example 1) Oxygen permeation amount 0.020 cc /
pkg / day, water vapor transmission amount 0.030 g / pkg /
Shows the processing time until it becomes less than day.

As Comparative Example 1, HMDSO 1.0 scc
m, the processing time when the HMDSO concentration was not changed at 100 sccm of oxygen.
HMDSO at 1.0 sccm, oxygen 20 sccm
The processing time when the concentration was not changed, the processing time when the raw material gas was separately supplied to the organic silicon compound and the oxygen as Comparative Example 3, the cryopump was added to the exhaust system as Comparative Example 4, and the HMDSO was 1.0 sccm and the oxygen was 100 sccm. 2 also shows the processing time when the HMDSO concentration change is not performed.

The untreated PET container has an oxygen permeation amount of 0.100 cc / pkg / day and a water vapor permeation amount of 0.1 kg / kg / day.
070 g / pkg / day.

The oxygen permeability was measured by MOCON OX.
According to TRAN, MOCON
The measurement was performed by PERMATRAN of the company.

[0049]

[Table 1]

[0050]

[Table 2]

As described above, by changing the HMDSO concentration, the film formation time can be shortened as compared with the case where oxygen post-treatment is performed after the HMDSO film formation. Further, in Comparative Examples 1 and 2, products having a predetermined gas barrier property could not be produced.

[0052]

As described above in detail, according to the present invention, a plastic container having a high gas barrier property can be produced in a short time without imposing a load on the exhaust system.

[Brief description of the drawings]

FIG. 1 is a conceptual sectional view of a gas barrier plastic container of the present invention.

FIG. 2 is a conceptual cross-sectional view of a gas barrier plastic container of the present invention in a state before film formation.

FIG. 3 is a conceptual cross-sectional view of the gas barrier plastic container of the present invention in a state during film formation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic container 2 External electrode 3 Gas introduction pipe 4 Exhaust port 5 Ground 6 Power supply

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor, Shigeru Shirai 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Wataru Iijima 1-1-5-1, Taito, Taito-ku, Tokyo Letterpress Inside Printing Co., Ltd. (72) Inventor Toshiaki Kakemura 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. F-term (reference) 3E062 AA09 AB02 AC02 JA02 JA07 JB22 JC01 JD01

Claims (13)

[Claims] At least one of silicon oxide, carbon, hydrogen, silicon and oxygen is formed on at least one side of a plastic container by a plasma CVD method using at least an organic silicon compound and a gas having oxygen or oxidizing power. A method for producing a plastic container, wherein the concentration of an organosilicon compound changes when forming a barrier layer containing at least one compound composed of two or more elements. 2. The method for producing a plastic container according to claim 1, wherein the concentration of the organosilicon compound decreases during film formation. 3. The method according to claim 1, wherein the concentration of the organic silicon compound repeatedly decreases and increases during the film formation. 4. At least one or more of silicon oxide, carbon, hydrogen, silicon and oxygen on a substrate by plasma CVD using at least an organic silicon compound and a gas having oxygen or oxidizing power. Wherein the supply of the organosilicon compound is stopped during film formation when forming a barrier layer containing at least one kind of a compound consisting of the above elements. 5. At least one or more of silicon oxide, carbon, hydrogen, silicon and oxygen on a substrate by a plasma CVD method using at least an organic silicon compound and a gas having oxygen or oxidizing power. Wherein the supply of the organosilicon compound is stopped in the course of film formation and the supply is started again when forming a barrier layer containing at least one compound composed of the above elements. 6. At least one or more of silicon oxide, carbon, hydrogen, silicon and oxygen on a substrate by plasma CVD using at least an organic silicon compound and oxygen or a gas having an oxidizing power. A method for producing a plastic container, comprising: stopping the supply of an organosilicon compound in the course of forming a film and restarting the supply when forming a barrier layer containing at least one compound of the following elements: 7. At least one or more of silicon oxide, carbon, hydrogen, silicon and oxygen on a substrate by plasma CVD using at least an organic silicon compound and a gas having oxygen or oxidizing power. Wherein the flow rate of the organic silicon compound and the flow rate of the gas having oxygen or oxidizing power are both changed when forming the barrier layer containing at least one compound composed of the above-mentioned elements. 8. A method for producing a plastic container, wherein the barrier layer according to claim 1 is provided on the inner surface of a bottle. 9. A method according to claim 1, wherein at least one side has silicon oxide, carbon,
At least one or two of hydrogen, silicon and oxygen
A plastic container comprising a plasma CVD barrier layer containing at least one compound composed of at least one kind of element and having a variable concentration of an organic silicon compound. 10. The plastic container according to claim 9, wherein the concentration of the organosilicon compound decreases during the film formation. 11. The method according to claim 1, wherein the concentration of the organosilicon compound decreases during the film formation.
The plastic container according to claim 9, wherein the increase is repeated. 12. The plastic container according to claim 9, wherein both the concentration of the organic silicon compound and the oxygen concentration change in the thickness direction. 13. A plastic container, wherein the barrier layer according to claim 9 is provided on the inner surface of a bottle.