JP3208948B2 - Transparent gas barrier material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent gas barrier material used in the field of packaging foods, pharmaceuticals, precision electronic parts and the like.

[0002]

2. Description of the Related Art In recent years, packaging materials used for packaging foods, pharmaceuticals, precision electronic parts, etc., suppress deterioration of contents, especially oxidation and deterioration of proteins and oils and fats in foods, and further improve taste and freshness. For pharmaceuticals that need to be retained and handled under aseptic conditions, suppress the deterioration of active ingredients and maintain their efficacy.For precision electronic components, prevent corrosion of metal parts, insulation failure, etc. To do
It is necessary to prevent the effects of oxygen, water vapor, and other gases that alter the contents of the packaging material, and it is required to have a gas barrier property that blocks these gases.

For this reason, polymer resin compositions which are generally said to have relatively high gas barrier properties, such as polypropylene (KOP), polyethylene terephthalate (KPET) or ethylene vinyl alcohol copolymer (EVOH) coated with vinylidene chloride resin, have been used. As a gas barrier material, a packaging film used as a packaging material, a metal foil made of a metal such as Al, or a suitable polymer resin composition (even a resin that does not have high gas barrier properties by itself)
Packaging films using a metal-deposited film on which a metal or a metal compound such as the above is deposited as a packaging material have been generally used.

However, a packaging film using only the above-mentioned polymer resin composition is only inferior in gas barrier properties as compared with a metal vapor-deposited film formed with a foil or vapor-deposited layer using a metal or a metal compound such as Al. However, it is easily affected by temperature and humidity, and the gas barrier property may be further deteriorated depending on the change. On the other hand, a metal vapor-deposited film on which a foil or a vapor-deposited layer is formed using a metal or a metal compound such as Al is less affected by temperature, humidity, and the like, and is excellent in gas barrier properties. And it cannot be confirmed.

To overcome these drawbacks, recently, as a packaging material, a thin film of silicon oxide such as silicon monoxide (SiO) or a thin film of magnesium oxide (MgO) has been formed on a substrate made of a transparent polymer material. A vapor-deposited film formed by a method such as vapor deposition has been developed, and a part thereof has been put on the market.

[0006]

SUMMARY OF THE INVENTION However, SiO
The vapor-deposited thin film is inferior in gas barrier properties to the above-mentioned Al foil or Al-deposited film, and furthermore, the SiO-deposited thin film itself has a light yellow color, so this was used for the above-mentioned packaging materials for foods and the like. In some cases, there is a problem that the contents may be considered to be altered.

A magnesium oxide (MgO) deposited thin film is colorless and transparent, has excellent light transmittance, and is slightly superior to the above-described silicon monoxide (SiO) deposited thin film in mechanical properties. For example, this magnesium oxide (MgO) vapor-deposited thin film, when used as a packaging material, can be processed (folded, pulled, laminated, etc.) into a package and printed with a design such as a character or picture. Alternatively, damage such as scratches occurs in the thin film in the post-processing after so-called deposition on the back surface, and gas such as air and water vapor penetrates from the damaged portion, thereby deteriorating the high gas barrier property that should be originally possessed. There is a problem of doing so.

[0008] That is, the conditions for use as a package include transparency enough to allow the contents themselves to be seen directly, high gas barrier properties to block gases that affect the contents, and processing into packages. Those that have mechanical strength (or flexibility) that does not lower the function against mechanical stress due to such as are required,
At present, no packaging material meeting all of these has been found.

Therefore, the present invention is a practical product which is colorless and transparent, has high gas barrier properties, and has mechanical strength which does not lower the gas barrier properties against the action of external bending or pulling by post-processing. It is an object to provide a highly transparent gas barrier material.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the invention according to claim 1 is to form a thin film of an inorganic compound on at least one surface of a substrate made of a transparent polymer material. in a transparent gas-barrier material comprising Te, a thin film of the inorganic compound is Ri Do from calcium oxide and calcium hydroxide, and calcium oxide and the calcium hydroxide
A transparent gas barrier material characterized in that the weight ratio is in the range of 95: 5 to 20:80 .

The invention described in claim 2 is an inorganic compound
That the thickness of the thin film is in the range of 50-3000mm
The transparent gas barrier material according to claim 1, wherein:

[0012] The invention described in claim 3 is a transparent gas barrier material, wherein the thickness of the thin film of the inorganic compound is in the range of 50 to 3000 °.

[0013]

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view illustrating a transparent gas barrier material of the present invention, and FIG. 2 is a schematic configuration diagram illustrating a vapor deposition apparatus for forming the transparent gas barrier material of the present invention.

First, the structure of the transparent gas barrier material of the present invention will be described with reference to FIG. Reference numeral 1 denotes a transparent gas barrier material of the present invention, and a thin film layer 3 made of inorganic compounds such as calcium oxide and calcium hydroxide is formed on the surface of a substrate 2. The thin film layer 3 composed of calcium oxide and calcium hydroxide may be formed on both sides of the substrate 2 or may be formed in a multilayer.

The base material 2 is a polymer material having transparency, and it is sufficient that the base material 2 is colorless and transparent, and is preferably used as a packaging material. For example, polyethylene terephthalate (PET), biaxially oriented polypropylene (O
PP), mechanical strength such as biaxially stretched nylon (ONy),
It has dimensional stability, and is used after being processed into a film. Further, a film having excellent smoothness and a small amount of the additive is preferable. The surface of the substrate 2 may be subjected to corona treatment, low-temperature plasma treatment, or ion bombardment treatment as a pre-treatment in order to improve the adhesiveness of the thin film. You may.

Although the thickness of the base material 2 is not particularly limited, it is suitable as a packaging material, there are cases where other layers are laminated, and a thin film layer 3 made of calcium oxide and calcium hydroxide is formed. Considering the workability when performing
It can be said that the range of １００100 μm is preferable.

In consideration of mass productivity, it is desirable to use a long film so that a thin film can be formed continuously.

The thin film layer 3 composed of calcium oxide and calcium hydroxide according to the present invention is composed of a substance in which calcium oxide has a bond between calcium atom (Ca) and oxygen atom (O) by X-ray photoelectron spectroscopy (XPS). Calcium hydroxide is made of a substance such as Ca (OH) ₂ or CaO (OH), which is capable of binding a calcium atom (Ca) to a hydroxyl group (OH).

In the present invention, the weight ratio between calcium oxide and calcium hydroxide is preferably in the range of 95: 5 to 20:80 by weight. If the calcium oxide content is larger than this range, the transparency and gas barrier properties are sufficient and the mechanical strength is good, but the gas barrier properties decrease due to stretching or rubbing. In addition, when calcium hydroxide is increased, the gas barrier property decreases, particularly under high humidity.

In the calcium oxide and calcium hydroxide of the present invention, silicon, aluminum, magnesium, etc. may be used as long as the transparency and gas barrier properties are not impaired.
Impurities such as iron, sodium, potassium, titanium, and zirconium may be contained.

In the present invention, the thickness of the thin film layer 3 composed of calcium oxide and calcium hydroxide is 50 to 3000 °.
Is desirably within the range, and the value is appropriately selected. However, if the film thickness is less than 50 °, the entire surface of the substrate 2 may not be formed into a film, and the function as a gas barrier material may not be sufficiently achieved. When the film thickness is 3
If the thickness is more than 000 °, the flexibility of the thin film cannot be maintained, and the thin film may be cracked by external factors such as bending and pulling after film formation.

There are various methods for forming the thin film layer 3 composed of calcium oxide and calcium hydroxide on the substrate 2 in the present invention. Examples of the method are as follows, but the method is not limited to the method described here. Absent.

As a first method, a thin film layer of calcium oxide is formed on the base material 2 by a usual vacuum evaporation method, a sputtering method, an ion plating method or the like using calcium oxide as a deposition material, In this method, a part of the calcium oxide is changed to calcium hydroxide by the heat treatment in step (a) to form the thin film layer 3 composed of calcium oxide and calcium hydroxide.

A second method is to form a thin film using calcium oxide as a deposition material in the presence of water vapor, a mixed gas of water vapor and an inert gas, or the like. There is a method of forming a thin film layer 3 composed of calcium oxide and calcium hydroxide by plating. The above two methods are simple in that the film forming apparatus can be easily implemented, and are preferable from the viewpoint of productivity.

Hereinafter, the method for forming the transparent gas barrier material of the present invention by the reactive evaporation method will be described together with the apparatus.

FIG. 2 is a schematic diagram illustrating a vacuum deposition apparatus 10 for forming the transparent gas barrier material of the present invention. In this device 10, the vacuum container 7 has an exhaust port 11
Is maintained at a pressure of 10 ^-1 to 10 ^-4 Pa by an exhaust device (usually a vacuum pump) not shown connected to.

The base material 2 is a polymer film having transparency and is long, and is provided with an unwinding roll 31 for continuously winding the polymer film and an outer periphery for forming a thin film on the polymer film. A cooling roll 33 on which the polymer film is partially wound, and a winding roll 34 for continuously winding the polymer film 2 are disposed, between the unwinding roll 31 and the cooling roll 33, and between the cooling roll 33 and the cooling roll 33. A guide roll 32 for guiding the polymer film smoothly is provided between the guide roll 32 and the take-up roll 34. The lower part of the apparatus is partitioned by a shielding plate 12 having an opening through which the cooling roll 33 is exposed, and a crucible 4 for storing the vapor deposition material 9 is arranged at a position facing the cooling roll 33. An electron gun 5 as a heating source for irradiating the vapor deposition material 9 with an electron beam and a gas introducing pipe 6 for introducing a reaction gas such as water vapor are arranged on the side surface. An electromagnetic coil 8 for efficiently irradiating the vapor deposition material 9 with an electron beam from the electron gun 5 is arranged on a side surface of the crucible 4. Further, the gas introduction pipe 6 is connected to a gas supply source (not shown) such as a gas cylinder through flow meters 61 and 62, and the composition of the gas introduced into the vacuum vessel 7 can be controlled by the values of the flow meters 61 and 62. It is possible.

When vapor deposition is performed by using the apparatus 10, the vacuum chamber 7 is evacuated, and then, in the case of ordinary vacuum vapor deposition, the gas introduction pipe 6 is connected in that state. The steam emitted from the electron gun 5 while the polymer film of the base material is caused to run at a predetermined speed through the respective rolls by making the steam alone or a mixed gas of the steam and the inert gas to a predetermined pressure. Heat the vapor deposition material 9 with the wire
It is vaporized and deposited on the polymer film of the substrate 2.

In the case of the above-mentioned reactive vapor deposition, the ratio of the amount of calcium oxide to calcium hydroxide can be arbitrarily determined by controlling the evaporation rate by changing the composition and flow rate of the reaction gas introduced into the vacuum vessel 7 and the output of the electron gun. Can be changed.

A more specific example of the transparent gas barrier material of the present invention will be described.

Example 1 A vacuum evaporation apparatus 10 using an electron beam heating method as shown in FIG. 1 using calcium oxide powder (purity: 2N) as an evaporation material for forming a thin film layer 3 composed of calcium oxide and calcium hydroxide. As a result, a 12 μm-thick polyethylene terephthalate (PE)
T) Calcium oxide thin film layer on one side of film about 500
蒸 着 was deposited to a thickness of Å to obtain a calcium oxide deposited film.

Next, this calcium oxide deposited film is kept in an atmosphere of 80 ° C. and 90% RH for 30 minutes, and the composition of the deposited layer is determined by X-ray photoelectron spectroscopy (XPS) (JPS-90SXV manufactured by JEOL Ltd.). As a result, the weight ratio between calcium oxide and calcium hydroxide was 80:20.

Example 2 A calcium oxide deposited film produced in the same manner as in Example 1 was kept in an atmosphere of 80 ° C. and 90% RH for 2 hours, and the composition of the deposited layer was similarly changed by X-ray photoelectron spectroscopy (XPS). ) (JPS-90SX manufactured by JEOL Ltd.)
As a result of analysis using V), the weight ratio of calcium oxide to calcium hydroxide was 40:60.

Comparative Example 1 A calcium oxide deposited film produced in the same manner as in Example 1 was not subjected to heat treatment, and the composition of the deposited layer was similarly changed by X-ray photoelectron spectroscopy (XPS) (JPS- 90SXV), the weight ratio of calcium oxide to calcium hydroxide was 9
8: 2.

COMPARATIVE EXAMPLE 2 A calcium oxide deposited film produced in the same manner as in Example 1 was not subjected to heat treatment, and the composition of the deposited layer was similarly changed by X-ray photoelectron spectroscopy (XPS) (JPS-90SX manufactured by JEOL Ltd.).
As a result of analysis using V), the weight ratio of calcium oxide to calcium hydroxide was 15:85 .

The transparency of the vapor-deposited films of Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated by measuring the light transmittance, and the gas barrier property was evaluated by measuring the oxygen permeability and the water vapor permeability. The mechanical strength of the deposited film was evaluated by measuring the value of oxygen permeability after the tensile test and after the fir test.

The following describes each measurement method for evaluating the gas barrier material, a tensile test (tensile resistance), and a kneading test (kneading resistance).

Light transmittance: The transmittance of light having a wavelength of 400 nm was measured using a spectrophotometer (UV-3100, manufactured by Shimadzu Corporation). ○ Oxygen permeability: Made by Modern Control (MOCO
N OXTRAN 10 / 50A) at 25 ° C.
The measurement was performed under a 100% RH atmosphere. ○ Water vapor transmission rate: Made by Modern Control Co. (MOC
ON PERMATRAN W6) at 40 ° C-
It was measured under a 90% RH atmosphere.

Tensile resistance: Oxygen permeability after 6% tension was measured using a tensile tester (Tensilon SS-207-EB manufactured by Toyo Baldwin Co., Ltd.) to determine the tensile resistance. ○ Kneading resistance: A coating amount of 60 μm no unstretched polypropylene (CP) was applied via a 4.0 g / m ² no adhesive
P) Kneading the film and the film laminated by dry lamination five times using a kneading tester (Gerbolex tester manufactured by Rigaku Kogyo Co., Ltd.), and then measuring the oxygen permeability,
Resistance to rubbing. Table 1 shows the results of measurement and evaluation based on the above test and measurement methods.

[0041]

[Table 1]

The units of the characteristic values in Table 1 are transparency (%), oxygen transmission rate (cc / m ² / day), and water vapor transmission rate (g /
m ² / day), mechanical strength [oxygen permeability (cc / m ²
/ Day)]. Comparative Example 1 has good transparency and gas barrier properties, but has poor tensile resistance and kneading resistance, and it can be said that Comparative Example 2 has poor gas barrier properties.

[Embodiment 3] The inside of the vacuum vessel was 2 × 10
After evacuating to ⁻³ Pa, water vapor was introduced so that the pressure in the vacuum vessel became 5 × 10 ⁻¹ Pa, and granular calcium oxide was used as a deposition material. The film was deposited on the same substrate to a thickness of about 1000 ° to obtain a deposited film.

The composition of this deposited layer was measured by X-ray photoelectron spectroscopy (X
When analyzed using (PS) (JPS-90SXV manufactured by JEOL Ltd.), the weight ratio of calcium oxide to calcium hydroxide was 50:50. Evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 The atmosphere in the vacuum vessel was controlled in the same manner as in Example 3, the running speed of the film was reduced to 1/5, and the same substrate as in Example 1 was deposited at a deposition rate of 20 ° / S. To a thickness of about 500 ° to obtain a deposited film. X-ray photoelectron spectroscopy (XPS)
When analyzed using (JPS-90SXV manufactured by JEOL Ltd.), the weight ratio of calcium oxide to calcium hydroxide was 15:85. Evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1. It can be said that the gas barrier property of Comparative Example 3 is not good as in Comparative Example 2.

[Comparative Example 4] Using a bulk silicon monoxide (purity of 3N) as a vapor deposition material, a silicon monoxide thin film layer was formed on the same substrate as in Example 1 by a vacuum vapor deposition apparatus using an electron beam heating method. The film was deposited to a thickness of 500 ° and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 The deposited film as a silicon monoxide (SiO) thin film layer had a light yellow color visually,
It can be said that the light transmittance is low, the oxygen permeability and the water vapor permeability after the resistance test are high, and the mechanical strength is inferior to the thin film layer composed of calcium oxide and calcium hydroxide.

From the comparative example, the conditions for use as the above-mentioned package were as follows: transparency so that the contents themselves could be seen directly, high gas barrier properties to block gases that affect the contents, and packaging. It can be said that it does not satisfy all the mechanical strength (or flexibility) that does not lower the function against mechanical stress due to processing on the body.

[0049]

As described above, according to the present invention, it is excellent in transparency and gas barrier properties after film formation, and in a post-processing step, it is formed into a thin film by the action of bending or pulling from the outside. It does not cause damage such as film cracking and has transparency, gas barrier property, mechanical strength, and flexibility that are the conditions used as the above-mentioned package, and exhibits sufficient practicality. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a transparent gas barrier material of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a vapor deposition apparatus for forming a transparent gas barrier material of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Transparent gas barrier material 2 Substrate 3 Thin film layer composed of calcium oxide and calcium hydroxide 4 Crucible 5 Electron gun 6 Gas introduction tube 7 Vacuum container 8 Electromagnetic coil 9 Deposition material 10 Vacuum deposition device 11 Exhaust port 31 Unwind roll 32 Guide roll 33 cooling roll 34 take-up roll 61, 62 flow meter

Claims (2)

(57) [Claims] 1. A transparent gas barrier material comprising a thin film of an inorganic compound formed on at least one surface of a substrate made of a transparent polymer material, wherein the thin film of the inorganic compound comprises calcium oxide and calcium hydroxide. And oxidation
The ratio of calcium to calcium hydroxide is 9 by weight.
A transparent gas barrier material characterized by being in the range of 5: 5 to 20:80 . 2. The method according to claim 1, wherein said inorganic compound thin film has a thickness of 50-3.
The transparent gas barrier material according to claim 1, wherein the transparent gas barrier material is within a range of 000 ° .