JPH06241978A - Gas transmittance measuring device for film - Google Patents

Abstract

PURPOSE:To achieve a highly sensitive measurement with a small amount of sample with a small area by installing a film retained at a flange by isolating a gas exposure container and a vacuum container hydromechanically and allowing the vacuum container to have a mass analyzer. CONSTITUTION:A flange 11 for retaining film isolate a 985 exposure container 12 from a vacuum container 13 hydromechanically. A pressure difference in reference to the vacuum container 13 is generated at a film 10 for exposing gas from the side of the exposure container 12 toward the sample film 10. A tool 15 for supporting film supports the film 10 against stress generated due to the pressure difference and no passage obstacles exist. The vacuum container 13 is provided with a space part 18 for tentatively retaining and accumulating the transmitted gas. When the transmittance to be measured is low, gas is tentatively accumulated at the space part 18. Then, after a proper amount of time passes, gas is introduced to a mass analyzer 14, thus improving measurement limitation and achieving measurement with improved sensitivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring gas permeability, and more particularly to an apparatus for highly sensitively measuring the gas permeability of a film, which is important in terms of gas barrier property. is there.

[0002]

2. Description of the Related Art Giving a gas barrier property to a film material is an important technique not only in the field of packaging foods and chemicals and precision electronic parts, but also in the field of sealing technology of electronic parts. Therefore, as a method for measuring and evaluating the gas barrier property of the film, there are, for example, a U-shaped tube manometer method, a gas chromatography method, and a coulometric method.

The coulometric method is the most sensitive method among these methods. One atmosphere of oxygen is exposed to one side of the film, oxygen permeating the film is sampled using nitrogen as a carrier gas, and permeated by an oxygen sensor. It measures oxygen. Specific examples of commercially available devices include OX-TRAN series (Nissan Sangyo) by MOCON.

[0004]

However, such a method has the following drawbacks. (i) Large area for measurement, ie, about 100 cm ²
A film-shaped test piece of at least about 11 cm or more is required. (ii) Not applicable to gases other than oxygen. (iii) The pressure of the gas exposed to the film cannot be controlled arbitrarily. (iv) When a film sample is used, the detection limit is 0.
It is about 1 cc · m ⁻² · day ⁻¹ .

[0005]

[Means for Solving the Problems] The gas barrier properties of films have been improved year by year, and the production methods have been diversified. Therefore, the advent of a measuring method with a small amount and small area and high sensitivity has been long awaited.

The inventors of the present invention have made various efforts to solve such a problem, and as a result, about 10 cm ² (about φ3.5c
The detection limit is 0.00 even with the film of area m).
The present invention has been achieved by developing an apparatus capable of measuring the gas permeability of a film under 1 cc · m ⁻² · day ⁻¹ or less and under any gas and any pressure condition.

That is, the present invention provides a gas permeability measuring device for a film, and a flange (11) for holding the film (10) whose gas permeability is to be measured while keeping both sides airtight, and the film (10). Container for exposing the film to be measured gas from one main surface of the
2) and a vacuum container (13) capable of evacuating to a pressure of 1 × 10 ⁻⁶ Torr or less with respect to the main surface of the film opposite to the gas-exposed surface, are connected, A device in which a film held on the flange can be placed in a fluidly isolated manner between the container and the vacuum container,
And a gas permeability measuring device for a film, characterized in that the vacuum container has a mass spectrometer (14),
In addition, the jig (1) which can support the film from the pressure difference between the atmospheric pressure and the vacuum and does not hinder ventilation is also provided.
5) is a gas permeability measuring device for a film, which the flange has, and wherein the mass spectrometer is calibrated for an arbitrary gas type and flow rate. A measuring device, the flange further comprising an O-ring (16) for sealing the film;
Furthermore, an O-ring (17) is provided on the outer side of the O-ring, and a gas permeability measuring device for a film capable of exhausting a pressure between the two O-rings to a pressure of 1 × 10 ^-1 Torr or less,
Further, the film gas permeability measuring device having a space portion (18) for temporarily holding and accumulating the gas that has permeated the vacuum container, and the space portion for temporarily holding and accumulating the permeated gas are valves ( 19) The gas permeability measuring device for a film as defined in claim 19), which is 1 × 10 ⁻⁹ Torr · l / with respect to helium in a state where the leak amount of the valve is closed. It is a gas permeability measuring device for a film, which is not more than sec. The film to be measured in the present application is not particularly limited,
Usually, a film having a thickness of about 10 to 500 μm is preferable.

The details of the apparatus according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, this apparatus basically comprises a film holding flange portion, a vacuum container, a mass spectrometer, and a gas exposure container. In FIG. 1, (10) is a sample film, (11) is a flange, (12) is a gas exposure container, (13) is a vacuum container, (14) is a mass spectrometer, and (15) is a film supporting jig. , (16) is an O-ring, (17) is an O-ring, (18) is a space for holding and accumulating gas, (19) is a valve, (20) is a vacuum pump, (21) is a vacuum pump, and (22) is Gas supply port,
(23) is a gas exhaust port.

The film holding flange (11) has a structure in which the O-ring (16) keeps the sample film (10) airtight. The flange can be used without particular limitation as long as it is a metal that emits little gas, but stainless steel (SU
S304, SUS316) and aluminum alloy (A6063)
Etc.) is desirable. If necessary, the inner surfaces of these flanges are electropolished or buffed. Further, a heating and cooling mechanism for making measurements at other than room temperature may be attached to the flange. The O-ring may be on one side as long as the film has good smoothness, but it is preferable to seal from both sides as shown in FIG. The squeezing margin of the O-ring is designed according to the design standard of the vacuum container,
0% is preferable, and 12 to 20% is more preferable.
The material of the O-ring needs to be soft enough not to damage the film while maintaining sufficient airtightness, and neoprene rubber, fluororubber, Kalrez or the like can be used. It is of course possible to use square rings instead of O-rings. In addition, in order to secure the airtightness between the film and the atmosphere, the O-ring for the film (1
It is a more preferable embodiment that another O-ring (17) is installed outside 6) and the space between them is evacuated by the vacuum pump (21).

As the vacuum pump used in the present invention, a rotary pump is sufficient, but it is of course possible to use a pump capable of obtaining a higher vacuum. Further, vacuum grease may be appropriately applied to the O-ring. Since the gas is exposed to the film from the gas exposure container (12) side, a pressure difference occurs between the film and the vacuum container (13).
As a jig (15) that supports the film from the stress generated by this pressure difference and does not hinder ventilation, a diameter of 1
A stainless disk with several mm holes.
A porous stainless filter or the like can be used.

The vacuum container (13) preferably has a space portion (18) for holding and storing the permeated gas. Thus, when the transmittance to be measured is low, gas is temporarily built up (accumulated) in the portion (18).
Then, after a suitable time has passed, it is possible to remarkably improve the measurement limit of the present measuring apparatus by introducing the gas into the mass spectrometer. This point is one of the features of the present invention.

A space portion (18) for holding and storing the permeated gas is defined by a valve (19),
In this case, the vacuum vessel (13) is connected to the flange (11) via a valve (19). The ultimate pressure of the vacuum container is preferably 1 × 10 ⁻⁶ Torr or less, more preferably 1 × 10 ⁻⁷ Tor.
It is rr or less. The pressure in the vacuum container is preferably measured with a vacuum gauge, and for that purpose, known ones such as an ionization vacuum gauge, a diaphragm vacuum gauge, a heat conduction vacuum gauge, and a viscous vacuum gauge can be used.

The valve (19) may have a helium leak amount of 1 × 10 ⁻⁹ Torr · l / sec or less in a closed state, and a high vacuum valve is preferably used, and more preferably used. , For ultra-high vacuum. To give a concrete example, Nidec Anelva Co., Ltd.
Ultra-high vacuum L-type polyimide valve (951-712
0), ultra high vacuum L type all metal valve (951-71
50) etc. The valve may be a manual valve, a compressed air driven valve, or an electromagnetically driven valve.
The vacuum vessel is preferably made of stainless steel or aluminum alloy, but is not necessarily limited to these materials. Although it is preferable to use a copper or aluminum metal seal for the flange portion, it is of course possible to seal the flange portion with an elastomer O-ring.

The gas permeability at any temperature can be measured by appropriately heating or cooling the flange portion and the container portion. The vacuum pump (20) may be a diffusion pump, a turbo molecular pump, a cryo pump, a sputter ion pump, a getter pump, or the like as a high vacuum pump, and among them, a turbo molecular pump having a stable exhaust speed. Is preferably used. The mass spectrometer (14) uses a magnetic field, uses a high frequency,
Although any one that uses a combination of a magnetic field and a high frequency can be used, a quadrupole mass spectrometer that uses a high frequency is preferable because it is small and easy to handle, and a quadrupole mass with a secondary electron multiplier is preferable. An analyzer is more preferred. To give a specific example of the quadrupole mass spectrometer, MSQ of Nippon Vacuum Co., Ltd.
-150 etc. Furthermore, in order to obtain a quantitative value, it is preferable that the mass spectrometer is calibrated to an appropriate flow rate of the measurement gas. However, calibration is not necessary because quantitative values are not necessary if only relative comparison between samples is performed. In the present invention, by using a mass spectrometer, it is possible to measure a rare gas that cannot be detected by a normal gas sensor.

The gas exposure container (12) has at least an inlet (22) for introducing the gas to be measured into the exposure container and an exhaust port (23) for exhausting the gas. If the pressure of the target gas is 1 atm, the gas may be gradually introduced from the cylinder through the inlet and the gas may be continuously discharged into the atmosphere from the outlet, but when performing measurement under reduced pressure, While introducing gas, exhaust the gas with a vacuum pump to maintain a predetermined depressurized state, or if the amount of gas permeation is small and fluctuations in pressure can be ignored within the measurement time, the container (12)
May be evacuated to a vacuum and then a predetermined gas may be introduced at a predetermined pressure. When it is desired to control the humidity of the gas, the bubbling gas and the dry gas can be appropriately mixed and introduced with water. Hereinafter, the present invention will be described with reference to examples.

[0016]

【Example】

(Example 1) First, the gas permeability of oxygen at room temperature is 50 μm, which is so small that it can be ignored with respect to a polymer film.
Then, the measurement limit of the device according to the present invention was investigated by using a SUS304 stainless steel foil having a diameter of 40 mm as a sample. After mounting the sample, it was evacuated to vacuum and the gas exposure chamber was filled with 1 atm of oxygen. When the pressure of the equipment reached 3 × 10 ^-7 Torr, close the valve (19) and remove the valve and film (1
Portion (1) defined by the valve (19) between
8) Build up (accumulation) of oxygen that permeates into (space for gas retention and accumulation). After building up for 3 hours, the valve (19) was opened and the built up oxygen was measured by the mass spectrometer (14). The signal intensity of the mass spectrometer was calibrated with an oxygen flow rate for a mass number of 32. FIG. 2 shows a graph obtained by measuring built-up oxygen. The integral of the curve of the curve in the figure corresponds to the oxygen build-up (however, the integral value of the background is excluded). From the figure, the oxygen build up in 3 hours is 1.
It can be estimated as 1 × 10 ⁻⁷ cc. Therefore, 24
It is 8.8 × 10 ^-7 cc in time (= 1 day). Since the area of the sample was 10 cm ² , the detection eye field for oxygen of this device was estimated to be 0.001 cc · m ⁻² · day ⁻¹ or less.

Example 2 A sample film obtained by laminating 10 μm thick polyvinylidene chloride on a 100 μm thick polyethersulfone film was used to measure the oxygen transmission rate at room temperature with this apparatus. After mounting the sample, oxygen bubbled with water was introduced into the gas exposure chamber and discharged from the outlet, whereby oxygen having a relative humidity of 100% and 1 atmosphere was contacted with the sample for 48 hours. Vacuum container pressure is 3 ×
When the pressure was 10 ⁻⁷ Torr or less, the power of the mass spectrometer was turned on, the valve was opened and closed, and the permeability of oxygen passing through the film was measured. When the valve (19) was closed, the oxygen permeability was 2.5 × 10 ⁻⁸ cc / s = 2.2 × 1 from the decrease Δq in the oxygen flow rate.
It can be seen that it is 0 ⁻³ cc / day. Sample area is 1
Since it was 0 cm ² , it was evaluated as 2.2 cc · m ⁻² · day ⁻¹ .

Example 3 A 200 nm layer of silicon oxide was formed on both sides of a 100 μm thick polyethersulfone film by plasma CVD using tetramethyldisiloxane and oxygen, and a 5 μm layer of polyvinyl alcohol was further formed. What was laminated by the bar coat method was used as a sample film. After mounting the sample film, oxygen bubbled with water was introduced into the gas exposure chamber and discharged from the outlet, whereby oxygen having a relative humidity of 100% at 1 atmospheric pressure was brought into contact with the sample for 48 hours. The pressure of the vacuum container is 3 × 10
^{-When the} temperature falls below ^-7 Torr, turn on the mass spectrometer power, close the valve (19) and build up oxygen for 1 hour, then open the valve (19) and measure the amount of built up oxygen at room temperature. did. FIG. 4 shows a graph at that time. Oxygen build-up in 1 hour, from the time integration value of the integration range of the figure (but not the background level),
Since it becomes 3.1 × 10 ^-7 cc, it will be 7.4 in 24 hours.
× 10 ^over 6 cc, and the the area of the sample is 10 cm ^2, gas permeability of the film 0.0074cc · m ^-2 ·
It is evaluated as day ^-1 .

(Comparative Example 1) The same film as in Example 3 was
16cm is made, MOCON company OX-TRAN100A
Oxygen with 100% relative humidity was exposed to the film at room temperature, and the measurement of oxygen permeability was tried at room temperature. It was found from the detector instructions that the oxygen permeability was 0.1 cc · m ⁻² · day ⁻¹ or less, but an accurate value could not be measured due to output drift.

Example 4 A sample film was prepared by forming a 200 nm layer of silicon oxide by plasma CVD using tetramethyldisiloxane and oxygen on both sides of a polyether sulfone film having a thickness of 100 μm. The gas exposure chamber (23) was once evacuated to a vacuum by a rotary pump, and then helium was introduced into the gas exposure container up to 1 Torr. Then, a constant amount of helium was continuously introduced while gradually evacuating to a vacuum, and a pressure of 1 Torr was maintained. After exposing the film to helium for 2 hours, valve (19) was closed for 35 seconds and then opened. The mass spectrometer monitored and recorded m / e = 4 (Figure 5). The measurement was performed at room temperature. 7.6 × 10 ⁻⁹ atm · cc / s was read from the decrease in the signal when the valve was closed. Also,
Helium built up in 35 seconds can be read as 2.7 × 10 ⁻⁷ atm · cc from the integration of FIG. 5,
7.7 × 10 ^over 9 atm · cc / s, and the good agreement with the former values. From the above Examples and Comparative Examples, it was confirmed that the gas permeability measuring device according to the present invention has significantly improved performance as compared with the conventional device.

[0021]

As is apparent from the above examples, according to the present invention, there is provided a gas permeability measuring device for a film capable of measuring the permeability of various gases and having an extremely high sensitivity. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of an apparatus according to the present invention.

FIG. 2 is a diagram showing a result of measuring a measurement limit for oxygen gas of the present apparatus using a stainless foil as a film.

FIG. 3 is a diagram showing the results of measuring oxygen gas permeability of a polyether sulfone film coated with polyvinylidene chloride.

FIG. 4 is a diagram showing the results of measuring gas permeability of a polyethersulfone film coated with a laminate of silicon oxide and polyvinyl alcohol.

FIG. 5 is a diagram showing the results of measuring the helium transmittance of a polyether sulfone film coated with silicon oxide.

[Explanation of symbols]

 10 Specimen Film 11 Flange 12 Gas Exposure Container 13 Vacuum Container 14 Mass Spectrometer 15 Film Support Jig 16 O-ring 17 O-ring 18 Space for Gas Retention and Accumulation 19 Valve 20 Vacuum Pump 21 Vacuum Pump 22 Gas Supply Port 23 Gas exhaust port

Claims (7)

[Claims] 1. A gas permeability measuring device for a film, comprising a flange (11) for holding while maintaining airtightness on both sides of a film (10) whose gas permeability is to be measured,
A container (12) for exposing the film to be measured gas from one main surface of the film, and 1 × 10 ^{−6 with} respect to the main surface of the film opposite to the gas-exposed surface.
A vacuum container (13) capable of evacuating to a pressure of Torr or less is connected, and the film held by the flange is placed in a fluidly isolated state from the container and the vacuum container. A gas permeability measuring device for a film, which is a possible device and in which the vacuum container has a mass spectrometer (14). 2. A jig (1) capable of supporting the film from a pressure difference between atmospheric pressure and vacuum and not hindering ventilation.
The gas permeability measuring device for a film according to claim 1, wherein the flange has 5). 3. The gas permeability measuring device for a film according to claim 1, wherein the mass spectrometer is calibrated for an arbitrary gas type and flow rate. 4. The flange has an O-ring (16) for sealing the film, and an O-ring (17) on the outer side of the O-ring, and 1 × 10 ^{-1 is provided} between the two O-rings.
The gas permeability measuring device for a film according to claim 1, which can be exhausted to a pressure of Torr or less. 5. The gas permeability measuring device for a film according to claim 1, wherein the vacuum container has a space portion (18) for temporarily retaining and accumulating the gas that has permeated. 6. The valve (19) defines a space for temporarily holding and accumulating the permeated gas.
The gas permeability measuring device for a film as described in. 7. The helium is 1 × 10 ⁻⁹ Torr · l / in a state where the leak amount of the valve is closed.
The gas permeability measuring device for a film according to any one of claims 1 to 6, which is not more than sec.