JP2010190751A - Gas permeability measuring device and gas permeability measuring method for film material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve remarkably sensitivity in measuring a gas permeability of a film material by avoiding a barrier of detection limit due to fluctuation or drift of background associated with measuring a real time. <P>SOLUTION: In the gas permeability measuring device to measure a gas permeability of a film material, a first vessel and a second vessel separated by the film material are formed when attaching the film material, the first vessel includes a measured gas supply mechanism supplying a measured gas to one side of the film material, the second vessel includes an inactive gas supply mechanism supplying an inactive gas to the side of the film material opposite to the side where the measured gas is supplied, a detector detecting the measured gas in the inactive gas is connected to the second vessel, and a state in which the inactive gas supplied from the inactive gas supply mechanism is sealed into the second vessel and a state in which the inactive gas sealed into the second vessel is introduced into the detector is selectively changed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas permeability measuring device for a film material and a gas permeability measuring method for a film material.

Since functional elements such as liquid crystal displays, organic EL displays, and organic solar cells are rapidly deteriorated by moisture and oxygen, it is necessary to completely seal them with the atmosphere. At present, the elements are sealed with a glass thin film. However, the cost of glass is large among the cost of these functional materials, and it has been considered to use a resin film instead of this glass thin film for the purpose of thinning and flexibility. Development is underway. In order to seal these elements by using a gas barrier film material, it is said that a permeability of 10 ⁻⁶ g / m ² / day level is required as a characteristic of the film material.

  As a conventional gas permeation measuring device for a film material, a so-called differential pressure method device is known in which a permeation chamber is evacuated and a permeation rate is measured from a change in the degree of vacuum (for example, Patent Document 1). Moreover, although the same principle is used, an apparatus for measuring with a mass spectrometer instead of a vacuum degree is also known (for example, Patent Document 2). Furthermore, although the gas to be measured is limited to oxygen and rare gas, a differential pressure apparatus that once holds and accumulates these is also known (Patent Document 3). Also known is a so-called isobaric device that measures the permeability by flowing a high-purity gas into the permeation chamber and measuring the concentration change of the target component therein (for example, Patent Document 4).

However, conventional gas permeability devices and gas permeability measurement methods (hereinafter referred to as “conventional devices” and “conventional methods”, respectively) mainly evaluate film materials used for packaging foods, medicines, etc. many those developed for, measuring the level of gas permeability ^{10 -2 g / m 2 / day~10} -4 g / m about ² / day was measurement limit.
In addition, in the conventional apparatus, the component concentration on the permeation chamber side is measured with a vacuum or a mass spectrometer in the differential pressure method, or is measured with a mass spectrometer or an infrared absorptiometric method in the isobaric method. Most of them are so-called continuous measurements in which the target component concentration of the gas to be measured that permeates a small amount of the film material is measured in real time. In order to stabilize the gas permeation of the film material, it takes a time of several hours to about a day even for a material having a high permeability, and it is assumed that the state of the measuring apparatus during that time is constant. However, in any measurement device, especially when measuring at high sensitivity, the background immediately before the start of measurement is the same even after a long period of time due to background fluctuations and drifts. It is extremely difficult to secure. For these reasons, the maximum level of continuous measurement of the gas permeability of the film material is about 10 ⁻⁴ g / m ² / day.

JP 2005-345342 A JP 2002-357533 A Japanese Unexamined Patent Publication No. 6-241978 JP 2005-233943

In view of the above problems, the present invention avoids limitations on detection limits due to background fluctuations, drift, etc. associated with real-time measurement, and can greatly improve the sensitivity of measurement of the gas permeability of film materials. An object of the present invention is to provide a measuring apparatus and a gas permeability measuring method.

  As a result of intensive studies to solve the above problems, the inventors of the present invention applied the film material to the two containers constituting the test environment chamber and the transmission chamber separated by the film material to be measured in a double O-ring. In order to prevent intrusion from the outside during this double O-ring, the inert gas passed through the gas purifier to the permeation chamber side to the gas permeation cell where the inert gas was passed as a high purity seal gas, The test environment chamber is supplied with conditioned air as a gas to be measured, and the gas permeation cell is closed with a flow path and a permeation chamber for allowing the inert gas to flow into the permeation chamber, while the inert gas is bypassed. A three-way valve that can be installed, and after allowing an inert gas to flow through the permeation chamber for a sufficient amount of time in advance, switch the three-way valve to bypass the inert gas and accumulate permeation components in the permeation chamber. To see through After accumulating the components, the three-way valve is switched to the permeation chamber side, and the components accumulated in the permeation chamber are pushed out at a stretch and the measurement is performed with the detector, and the present invention is completed. It was.

That is, the gist of the present invention resides in the following [1] to [9].
[1] A gas permeability measuring device for measuring a gas permeability of a film material, wherein a first container and a second container separated by the film material when the film material is mounted are formed, The container has a measured gas supply mechanism for supplying the measured gas to one surface of the film material, and the second container is the surface of the film material to which the measured gas is supplied An inert gas supply mechanism for supplying an inert gas to the opposite surface, a detector for detecting a gas to be measured in the inert gas connected to the second container, The state in which the inert gas supplied from the inert gas supply mechanism in the container is sealed and the state in which the inert gas sealed in the second container is introduced into the detector can be selectively made possible. An apparatus for measuring gas permeability.
[2] The gas permeability measuring device according to [1], further including a sealing mechanism that tightly seals an outer edge portion of the film material to form the first container and the second container.
[3] The gas permeability measuring apparatus according to [2], further including a seal chamber that can seal the seal mechanism.
[4] The gas permeability measuring apparatus according to [3], further comprising means for supplying an inert gas to the seal chamber.
[5] The gas permeability measuring device according to any one of [1] to [4], wherein the sealing mechanism and the sealed container are previously baked before measuring the film material.
[6] The detector has a response time of 60 seconds or less, and is selected from the group consisting of a hygrometer, a mass spectrometer, and a pulse discharge detector. [1] to [5] ] The gas-permeation rate measuring apparatus according to any one of the above.
[7] The gas permeability measuring device according to any one of [1] to [6], wherein the gas to be measured is air containing moisture, and the inert gas is helium or argon.
[8] A gas permeability measuring method for measuring a gas permeability of a film material using the gas permeability measuring device according to any one of [1] to [7].

[9] After replacing the inside of the second container with an inert gas and sealing it, supplying the gas to be measured into the first container for a certain period of time, and then supplying the inert gas sealed in the second container The gas permeability measuring method according to [8], which is introduced into the detector.

As in the present invention, by using the apparatus of the present invention, the measurement gas component that has permeated through the film material is accumulated for a certain period of time and then pushed out at a stroke. You can plan. In addition, when measuring the gas permeability of the film material with high sensitivity, fluctuations in apparatus sensitivity and background become a problem, but the method of the present invention only requires apparatus stability for about 5 minutes, so it is accurate. Measurement is possible.

Furthermore, by adjusting the time for accumulating the gas to be measured, the application range of the detector to be used is expanded, and it is possible to measure a film material having a low gas permeability even if an inexpensive and low sensitivity detector is used. If a highly sensitive detector is used, gas permeation measurement up to 10 ^-6 g / m ² / day becomes possible.
This makes it possible to accurately evaluate a high gas barrier film material used for a material element such as a solar cell, an organic EL display, or a liquid crystal display.

It is a figure which shows an example of a gas permeability measuring apparatus. It is a figure which shows the state of the gas permeability measuring apparatus at the time of trapping the inert gas at the time of gas permeability measurement in a container. It is a figure which shows the state of the gas permeability measuring apparatus at the time of introducing the inert gas at the time of gas permeability measurement to a detector. It is a figure which shows the state of the gas permeability measuring apparatus at the time of introducing the inert gas at the time of gas permeability measurement to a detector. 3 is a graph showing the results of gas permeability measurement with the mass spectrometer of Example 1. FIG. 4 is a graph showing the results of gas permeability measurement with a mass spectrometer of Reference Example 1. Overall view of the gas permeability measuring device

The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents. The details will be described below.
In the present invention, the film material for measuring the gas permeability is not particularly limited. Usually, the film base is polyethylene terephthalate, nylon, polyethylene, polypropylene, polyimide, etc., and a metal oxide, metal nitride, or metal thin film is used. Film material having a barrier layer.

In the gas permeability measuring apparatus according to the present invention, two sealed containers are used, but are not particularly limited as long as the gas supplied into the container can be sealed. Usually, it is stainless steel, etc. Among them, SUS304, SUS304L, SUS316, etc. are preferable.
Of the two sealed containers, the first container has a measured gas supply mechanism, but the measured gas supply mechanism is particularly limited as long as the measured gas supply mechanism can expose the measured gas to one side of the film material. Not. For example, a constant flow of air is flowed by a mass flow controller and bubbled into a container containing pure water to produce water saturated with water vapor, and then air of any relative humidity is supplied by mixing it with a constant flow of dry air. I can do it.

Further, the second container has an inert gas supply mechanism. The inert gas supply mechanism exposes the inert gas to the opposite surface of the film material to which the gas to be measured is exposed. There is no particular limitation as long as the mechanism can be used. For example, a high-purity inert gas can be supplied using a mass flow controller after further purifying it through a gas purification apparatus.
Further, the second container is provided with a state in which an inert gas is sealed in the container, and means for introducing the inert gas sealed in the second container into the detector. These means can be switched, and at least one of the above states can be selected as desired by switching. Specifically, for example, as shown in FIG. 1, a three-way valve is installed in a line for supplying an inert gas to the second container, and one port is supplied from the inert gas supply mechanism to the second container. The other port is connected to the downstream side of the line. Furthermore, another one-way valve is installed in the line from the gas outlet of the second container to the detector, and one of its ports is connected to the upstream side of the line from the gas outlet of the second container to the detector, Connect the other port to the downstream side of the line. Then connect the remaining ports of both three-way valves. By installing the three-way valve in this way, the flow direction of the inert gas is changed from the second container to the detector by operating both the three-way valves as in the gas permeability measurement of the film material in FIG. It is possible to switch between the state of connection and the state of sealing the inert gas in the second container by passing the flow of the inert gas through the bypass line as shown in FIG. Further, as shown in FIG. 4, it is possible to create a state in which an inert gas flows from the second container to the detector and a state in which the inert gas is accumulated in the second container using a two-way valve. However, with this method, the blank amount from the two-way valve increases twice as compared with the case where the three-way valve is used. In other words, since blanks are always generated from both closed sides of the two-way valve, as a result, all the blanks generated on both sides of the valve are brought in at the time of re-measurement after accumulation, and as a result, the blank of the second container Will increase. A blank generated from the inert gas supply side and the exhaust side can be completely removed by always flowing an inert gas through the bypass line using a three-way valve, which is preferable.

Moreover, the temperature in the container at the time of measuring the gas permeability of the film material is not particularly limited, but is usually in the range from room temperature to 40 ° C. Furthermore, the pressure in the first container and the second container at the time of measurement may be the same or different, but from the viewpoint of improving the accuracy of measurement, the pressure in the first container and the second container The pressures are preferably equal.
In the gas permeability measuring apparatus according to the present invention, a detector for detecting a gas to be measured is used. The detector is not particularly limited as long as it can measure the concentration of the gas to be measured in the inert gas. Usually, a commercially available detector may be used as long as it has a sensitivity of ppm level, for example, a mass spectrometer, a pulse discharge detector, a hygrometer, a dew point meter, a moisture meter, etc., preferably a hygrometer and a mass spectrometer. The mass spectrometer is selected from the group consisting of a device and a pulse discharge detector, and more preferably a mass spectrometer having a higher sensitivity and a function capable of separating a gas to be measured. Further, the response time of these detectors is not particularly limited, but is preferably 60 seconds or less.

The detector is connected to the second container and is used to measure the gas in the second container.
The gas permeability measuring device of the present invention may have a seal mechanism that tightly seals the outer peripheral portion of the film material. Specifically, O-ring is preferably used because it does not damage even if the film material is narrowed.

  Further, a seal chamber may be further provided, and the seal chamber is preferably a sealed space surrounding the seal mechanism. The reason for this is that O-rings are extremely gas permeable and leaky, so in measurements with extremely low gas permeability, gas permeation and leakage from the atmosphere cannot be ignored with a single seal mechanism. End up. For this reason, it is possible to completely block gas permeation from the atmosphere by using a double sealing mechanism with the seal chamber and flowing an inert gas into the seal chamber.

Moreover, it is preferable to use what was baked beforehand for the airtight container and sealing mechanism of this invention. The reason is that, WVTR (water vapor permeability) gas permeability measurement level 10- ⁶ g / m ² / day when a level container and valve of the film material, the blank amount from the member used with such an O-ring (background ) Greatly affects the measured value. In other words, if the WVTR (moisture permeability) is about 10 ^-1 g / m ² / day level, the blank can be lowered by performing a preliminary purge at the experimental temperature (eg 40 ° C. or 85 ° C.). ^When trying to measure up to ^-6 g / m ² / day level, this blank amount becomes overwhelmingly larger than the measured value, making it impossible to measure.

For example, in the case of a SUS container, it is desirable to perform baking at a temperature of about 200 ° C., but at that temperature, the heat resistance temperature of the O-ring is exceeded and the quality deteriorates. O-rings have different heat resistance temperatures depending on the material, but at the same time, the gas generation behavior is also different. A resin material such as O-ring has a very large amount of generated water, so it is very important to completely degas it.
For these reasons, it is preferable to perform temperature and time baking suitable for each member used for measurement. Specifically, it is desirable to 1) measure the gas generation pattern for each individual member, 2) perform optimum temperature / time baking for each member, and 3) finally combine the respective members into a measurement container. For example, the SUS container, the valve and the pipe are baked at 200 ° C. for one week under inert gas flow. Apart from baking these members, O-rings are baked at 120 ° C. for 3 days under inert gas flow. When baking is completed, the set is brought into an argon glove box, and an O-ring is incorporated therein to form a measurement container, and a film material to be measured is set in the container in this state. Thereafter, the measurement is performed after purging by flowing an inert gas through the first and second containers for 1 to 2 days under an experimental temperature condition (for example, 40 ° C.).

The gas to be measured of the present invention is not particularly limited, but is usually water, air containing water, oxygen, hydrogen, carbon dioxide, etc., preferably water, air containing water, oxygen, Air containing water is preferable.
Although the inert gas of this invention is not specifically limited, Usually, helium, argon, nitrogen, etc. are preferable, Preferably they are helium or argon.

A typical gas permeability measuring apparatus according to the present invention is shown in FIG.
In FIG. 1, a container 10 is configured by sandwiching a film to be measured 13 with double O-rings 14 and tightening two containers on the upper and lower sides with bolts and nuts. Between the double O-rings (sealing chamber), an inert gas, which is a sealing gas, is circulated from the sealing gas inlet 15 to prevent leakage from the atmosphere and permeation of the gas to be measured, from the sealing gas outlet 16. Exhaust.

  A gas to be measured is circulated from the gas to be measured inlet 17, flows into the test environment chamber 11 that is the first container, and is exhausted from the gas to be measured outlet 18. The inert gas flows from the three-way valve 21 through the inert gas inlet 19 to the permeation chamber 12 as the second container during pre-purging or when introduced into the detector after being accumulated in the permeation chamber 12 as the second container. The active gas outlet 20 is introduced into the detector 23 through the three-way valve 22. During accumulation of the gas to be measured, the inert gas flows through the three-way valve 21 directly to the three-way valve 22 and flows to the detector 23 side.

  FIG. 7 shows an overall view of the gas permeability measuring device of the present invention. In FIG. 7, the entire gas permeable container can be placed in a test thermostat 30 and the temperature can be adjusted according to the experimental conditions. When the inert gas is helium, the gas in the high-purity helium cylinder 26 is purified by the gas purifier 25 placed immediately before the apparatus, and then a constant flow rate is supplied to the sealing gas or the inert gas via the mass flow controller 24, respectively. Supplied as In the test environment chamber 11, the air from the air cylinder is supplied to the humidity control device 28 via the mass flow controller 24, and air with a constant humidity is produced and supplied to the test environment chamber 11.

The gas permeability measuring method of the present invention will be described below.
First, the inert gas is circulated from the gas inlet 17 to be measured while the inert gas is circulated from the sealing gas inlet 15 and exhausted from the sealing gas outlet 16 between the double O-rings. 11 and exhausted from the gas outlet 18 to be measured. As shown in FIG. 3, the inert gas flows from the three-way valve 21 to the permeation chamber 12 through the inert gas inlet 19 and is exhausted from the inert gas outlet 20 through the three-way valve 22. In this state, purge is performed for the required time at the experimental temperature to sufficiently expel the gas component to be measured adsorbed on the surface of the film to be measured 13 or contained in the film material. After confirming that the blank is sufficiently lowered by the detector 23, a blank test is performed before measuring the transmittance of the film material.

The blank test is a test for obtaining all blanks from a container while accumulating for a certain time.
For example, this is performed as follows. With the inert gas flowing from the measured gas inlet 17 to the test environment chamber 11, the three-way valves 21 and 22 are switched to the bypass side as shown in FIG. 2 so that the inert gas flows through the three-way valves 21 and 22. , Do not flow to the permeation chamber 12 side. In this state, all blanks are accumulated in the permeation chamber 12 for a certain period of time, and after a certain period of time, the three-way valves 21 and 22 are switched as shown in FIG. The gas accumulated in the chamber 12 is expelled at a stroke and introduced into the detector 23 through the inert gas outlet 20 and the three-way valve 22. The detector 23 keeps the background sufficiently stable in advance, starts measurement immediately before the discharge, and continues the measurement until the value of the gas component to be measured returns to the value immediately before the discharge.

This result is the total blank value generated from the container, and the value obtained by subtracting this blank value from the subsequent permeation test value is the true gas permeation amount.
The measurement gas permeability is measured by flowing a gas containing the measurement gas from the measurement gas inlet 17 to the test environment chamber 11 and simultaneously switching the three-way valves 21 and 22 to the bypass side as shown in FIG. So that the permeate gas accumulates. Similar to the blank test, after a certain time has elapsed, the three-way valves 21 and 22 are switched as shown in FIG. 3 to expel the gas to be measured accumulated in the permeation chamber (first chamber) 12 and introduce it into the detector 23 to be measured. Detect the measurement gas.

Thereafter, a certain amount of the gas to be measured is injected into the high purity gas, and its intensity is detected by the detector.
The amount of permeated gas is obtained by comparing this area with the measured area.
As described above, the inert gas is sealed in the second container whose interior is previously replaced with the inert gas, and the gas to be measured is supplied into the first container for a certain period of time. By introducing the sealed inert gas into the detector, there are the following advantages. That is, when measured as described above, for example, when a mass spectrometer is used as a detector, the measurement data has a peak shape as shown in FIG. In continuous measurement like the conventional method, the concentration is measured. Then, a gas containing a certain concentration of gas to be measured must be introduced into the detector, but at the 10 ^-6 g / m ² / day level, this concentration becomes 1 ppb level, and it is not possible to create a gas with such a concentration. It is almost impossible, and there are various problems such as adsorption to the piping to be used. In fact, actual measurement is impossible, and there is no other way but to calibrate by scouring the measured value of high concentration standard gas.

On the other hand, since the data obtained by the method of the present invention has a peak shape, this area, that is, the amount can be obtained. Therefore, it is only necessary to introduce a calibration gas containing a certain amount of gas to be measured.
The flow rate of the inert gas affects the response time. When using a detector with a slow response, the flow rate can be reduced. On the other hand, for a detector with a sufficiently fast response time, the flow rate can be increased. Is possible. When a mass spectrometer or a pulse discharge detector is used, the flow rate is about 50 to 500 ml / min. Since the sealing gas is used to prevent permeation from the outside air, it may be a small amount and may be about 10 to 50 ml / min. Since the test gas flow rate is also sufficiently large compared to the permeation amount of the gas to be measured, it is sufficient to flow.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.
<Example 1>
Using the apparatus of FIG. 1, the water vapor permeability of a film material obtained by depositing a silicon oxide film on a polyethylene terephthalate film was measured. In the present invention, a mass spectrometer (model number: AGS-7000) manufactured by Canon Anelva is used as the detector 23. The moisture permeability was calculated from a detected current value of water in this mass spectrometer using a calibration curve.

First, high-purity helium in the test environment chamber is 50 ml / min, and high-purity helium in the permeation chamber is 100 ml / mi.
n, Supply high-purity helium at 20ml / min during double O-ring, film and container
After fully purging the O-ring, switch the three-way valve to accumulate at 40 ° C for 2 hours, then switch the three-way valve and push it out with high-purity helium at a stretch and measure the blank with a mass spectrometer. Obtained. The transmittance blank value was 0.1 × 10 ⁻⁴ g / m ² / day.

After that, air with 90% relative humidity in the test environment chamber is 50 ml / min, high-purity helium in the permeation chamber side is 100 ml / min, and the test environment chamber and the permeation chamber are in the same pressure state. After supplying 20 ml / min of high-purity helium and thoroughly purging, switch the three-way valve to accumulate at 40 ° C for 2 hours, then switch the three-way valve and push it out with high-purity helium at once, and transmit the permeability with a mass spectrometer Was measured to obtain data 2) in FIG. The value obtained was 2.6 × 10 ⁻⁴ g / m ² / day. Therefore, the water permeability after subtracting the blank value was 2.5 × 10 ⁻⁴ g / m ² / day.

<Reference Example 1>
In order to estimate the measurement limit by the apparatus of the present invention, the film material is removed, no gas is allowed to flow into the test environment chamber, and a completely closed gas permeation cell is constructed with a blank stopper at its gas inlet and outlet. High purity helium is supplied at 100 ml / min, and 20 ml / min high purity helium is supplied between the double O-rings, and the permeation chamber is sufficiently purged in advance, then the three-way valve is switched and accumulated at 40 ° C. for 24 hours. Thereafter, the three-way valve was switched, and the gas pushed out at once with high purity helium was detected with a mass spectrometer. The measurement data obtained by the mass spectrometer is shown in FIG. The measurement blank obtained from the peak area was equivalent to 1 × 10 ⁻⁶ g / m ² / day. From this measurement, it was confirmed that a water vapor permeable film of about 10 ⁻⁶ g / m ² / day can be measured.

10 containers
11 Test environment room
12 Permeation chamber
13 films
14 O-ring
15 Gas inlet for sealing
16 Gas outlet for sealing
17 Measured gas inlet
18 Gas outlet to be measured
19 Inert gas inlet
20 Inert gas outlet
21-22 Three-way valve
23 Detector
24 Mass flow controller
25 Gas refiner
26 Helium cylinder
27 Air cylinder
28 Humidity control device
30 test chamber
31 Piping thermostat
32 Gas inlet
33-34 two-way valve

Claims (9)

  A gas permeability measuring device for measuring a gas permeability of a film material, wherein a first container and a second container separated by the film material when the film material is mounted are formed, and the first container is A measurement gas supply mechanism for supplying a measurement gas to one surface of the film material, wherein the second container is opposite to the surface of the film material to which the measurement gas is supplied; An inert gas supply mechanism for supplying an inert gas to the surface, and a detector for detecting a gas to be measured in the inert gas is connected to the second container; It is possible to selectively enable a state in which the inert gas supplied from the inert gas supply mechanism is sealed and a state in which the inert gas sealed in the second container is introduced into the detector. Gas permeability measuring device.   The gas permeability measuring apparatus according to claim 1, further comprising a sealing mechanism that tightly seals an outer edge portion of the film material to form the first container and the second container.   The gas permeability measuring apparatus according to claim 2, further comprising a seal chamber capable of sealing the seal mechanism.   The gas permeability measuring apparatus according to claim 3, further comprising means for supplying an inert gas to the seal chamber.   The gas permeability measuring device according to any one of claims 1 to 4, wherein the sealing mechanism and the sealed container are baked in advance before measuring the film material.   6. The detector according to claim 1, wherein the detector has a response time of 60 seconds or less and is selected from the group consisting of a hygrometer, a mass spectrometer, and a pulse discharge detector. The gas permeability measuring apparatus as described.   The gas permeability measuring apparatus according to claim 1, wherein the gas to be measured is air containing moisture, and the inert gas is helium or argon.   A gas permeability measuring method for measuring a gas permeability of a film material using the gas permeability measuring device according to claim 1.   After the inside of the second container is replaced with an inert gas and sealed, the gas to be measured is supplied into the first container for a certain time, and then the inert gas sealed in the second container is removed from the detector. The gas permeability measuring method according to claim 8, wherein the gas permeability measuring method is introduced into the gas.

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