ASTM F2622-20

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Designation: F2622 − 08 (Reapproved 2013) F2622 − 20
Standard Test Method for
Oxygen Gas Transmission Rate Through Plastic Film and
Sheeting Using Various Sensors
This standard is issued under the fixed designation F2622; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers a procedure for determination of the steady-state rate of transmission of oxygen gas through plastics
in the form of film, sheeting, laminates, coextrusions, or plastic-coated papers or fabrics. It provides for the determination of ((1)1)
oxygen gas transmission rate (O GTR), ((2)2) the permeance of the film to oxygen gas (PO ), and (3)(3) oxygen permeability
2 2
coefficient (P’O(P'O ) in the case of homogeneous materials.
1.2 This test method does not purport to be the only method for measurement of O GTR. There may be other methods of
O GTR determination that use other oxygen sensors and procedures.
1.3 This test method has intentionally been prepared to allow for the use of various sensors, devices, and procedures. The
precision and bias of each design needs to be individually established to determine the applicability of that instrument or method
to meet the needs of the user.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1898 Practice for Sampling of Plastics (Withdrawn 1998)
D3985 Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using a Coulometric Sensor
3. Terminology
3.1 Definitions:
3.1.1 oxygen permeability coeffıcient (P'O )—the product of the permeance and the thickness of film. The permeability is
meaningful only for homogeneous materials, in which case it is a property characteristic of the bulk material. The oxygen
permeability coefficient should not be used, unless the relationship between thickness and permeance has been verified on tests
using several different thicknesses of the material. The SI unit of oxygen permeability is the mol/(m·s·Pa). The test conditions (see
3.1.3) must be stated.
3.1.2 oxygen permeance (PO )—the ratio of the O GTR to the difference between the partial pressure of O on the two sides
2 2 2
of the film. The SI unit of permeance is the mol/(m ·s·Pa). The test conditions (see 15.1) must be stated.
This test method is under the jurisdiction of ASTM Committee F02 on FlexiblePrimary Barrier Packaging and is the direct responsibility of Subcommittee F02.10 on
Permeation.
Current edition approved Oct. 1, 2013June 1, 2020. Published November 2013July 2020. Originally approved in 2008. Last previous edition approved in 20082013 as
F2622 – 08. 08 (2013). DOI: 10.1520/F2622-08R13.10.1520/F2622-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2622 − 20
3.1.3 oxygen transmission rate (O GTR)—the quantity of oxygen gas passing through a unit area of the parallel surfaces of a
plastic film per unit time under the conditions of test. The SI unit of transmission rate is the mol/(m ·s). The test conditions,
including temperature and oxygen partial pressure on both sides of the film must be stated.
3.1.3.1 Discussion—
3 2 3
A commonly used unit of O GTR is the cm (STP) ⁄m ·d) at one atmosphere pressure difference where 1 cm (STP) is 44.62 μmol,
1 atm is 0.1013 MPa, and one day is 86.4 × 10 s. The O GTR in SI units is obtained by multiplying the value in inch-pound units
-10
by 5.160 × 10 .
4. Summary of Test Method
4.1 The oxygen gas transmission rate is determined after the sample has equilibrated in a controlled test environment. Control
of carrier gas flow rate (for concentration detectors), relative humidity, temperature, and oxygen concentration in both the carrier
gas and permeant (test) gas chambers is critical.
4.2 The specimen is mounted as a sealed semi-barrier between two chambers at ambient atmospheric pressure. A stream of
nitrogen slowly purges one chamber and the other chamber contains oxygen. As oxygen gas permeates through the film into the
nitrogen carrier gas, it is transported to the detector where it produces a signal representing the oxygen transmission rate.
5. Significance and Use
5.1 The O GTR is an important determinant of the packaging protection afforded by barrier materials. It is not, however, the
sole determinant, and additional tests, based on experience, must be used to correlate packaging performance with O GTR. It is
suitable as a referee method of testing, provided that the purchaser and the seller have agreed on sampling procedures,
standardization procedures, test conditions, and acceptance criteria.
5.2 Testing which has compared select instruments with other sensors to the instruments specifically described in Test Method
D3985 is shown in Section 16, Precision and Bias, of this method.
5.3 The Precision and Bias section of this method shows results using several instruments with non-coulometric and
coulometric sensors.
6. Interferences
6.1 The presence of certain interfering substances in the carrier gas stream may give rise to unwanted electrical outputs and error
factors. Interfering substances include carbon monoxide, hydrocarbons, free chlorine, and some strong oxidizing agents. Exposure
to carbon dioxide should also be minimized to avoid damage to the sensor through reaction in some sensor types.
7. Apparatus
7.1 Oxygen Gas Transmission Apparatus, with the following:
7.1.1 Diffusion Cell shall consist of two metal halves, which, when closed upon the test specimen, will accurately define a
circular area. The volume enclosed by each cell half, when clamped, is not critical; it should be small enough to allow for rapid
gas exchange, but not so small that an unsupported film which happens to sag or bulge will contact the top or bottom of the cell.
The diffusion cell shall be provided with a thermometer well for measuring temperature.
7.1.1.1 O-Ring—Various designs may be included in the diffusion cell design. Some systems may require vacuum grease to
form a proper seal. The design will define the test area of the film as it is tested.
7.1.1.2 Diffusion Cell Pneumatic Fittings—The diffusion cell shall incorporate suitable fittings for the introduction and exhaust
of gases without significant loss or leakage.
7.1.1.3 It is desirable to thermostatically control the diffusion cell. A simple heating or heating/cooling system regulated to
60.5°C, is adequate for this purpose. A thermistor sensor and an appropriate control circuit will serve to regulate the cell
temperature unless measurements are being made close to ambient temperature. In this case, it is desirable to provide cooling
capability to remove some of the heat.
7.1.1.4 Experience has shown that arrangements using multiple diffusion cells are a practical way to increase the number of
measurements that can be obtained from a single sensor. Valves connect the carrier gas side of each individual diffusion cell to the
sensor in a predetermined pattern. Carrier gas is continually purging the carrier gas sides of those cells that are not connected to
the sensor. Either test gas or carrier gas, as is appropriate, purges the test gas chamber of any individual cell.
7.1.2 Flow Controller—A flow controller will control the flow of carrier and test gases with sufficient precision to allow
determination of the oxygen permeability in instruments which calculate the oxygen permeability based on the oxygen
concentration change in the carrier gas stream. In some instruments (such as the Coulometric), the flow rate does not need to be
controlled as precisely.
7.1.3 Flow Switching Valves—Valves for the switching of the nitrogen and test gas flow streams.
F2622 − 20
7.1.4 Sensor—An oxygen-sensitive sensor with sufficient sensitivity and precision to yield meaningful results can use various
operating principles including coulometric, electrochemical and zirconium oxide. Different sensors may have different levels of
sensitivity. The user should select the instrument/sensor system which will adequately cover the oxygen permeation range and
degree of precision of interest.
7.1.5 Data Recording System—An appropriate data recording system shall record all pertinent information. Various integrated
and external computer systems have been found effective.
8. Reagents and Materials
8.1 Nitrogen Carrier Gas shall consist of nitrogen. The carrier gas shall be dry and contain not more than 5 ppm of oxygen.
If catalysts or other oxygen absorbers are employed, a higher oxygen level may be found to be acceptable. If other gases are needed
to be included in this nitrogen to allow catalysts to function they may be incorporated up to 5 %.
8.2 Oxygen Test Gas shall be dry and contain not less than 99 % oxygen (except as provided in 13.8).
8.3 Sealing Grease—For some instrument types, a vacuum or stopcock grease may be required to seal the specimen film in the
diffusion cell.
8.4 Water for Humidification—For humidification of the carrier and permeant gas streams, ultra-high purity water is required
for some instrument types to prevent plugging of the humidification system. This water should have a resistivity of at least 18
MΩ.MΩ. An example of a suitable type is high-pressure liquid chromatography (HPLC) water.
9. Precautions
9.1 Temperature and relative humidity are critical parameters affecting the measurement of O GTR. Careful temperature and
relative humidity control can help to minimize variations due to environmental fluctuations. During testing, the temperature shall
be monitored to the nearest 0.5°C and the relative humidity to the nearest 0.5 percent. The average conditions and range of
conditions experienced during the test period shall both be reported.
9.2 The sensor may require a relatively long time to stabilize to a low reading characteristic of a good barrier after it has been
used to test a poor barrier such as low-density polyethylene. For this reason, materials of comparable gas transmission qualities
should be tested together.
9.3 Back diffusion of air into the unit is undesirable. Care should therefore be taken to ensure that there is a flow of nitrogen
through the system at all times. This flow can be lowered when the instrument is not being used.
9.4 Elevated temperatures can be used to hasten specimen outgassing, provided that the treatment does not alter the basic
structure of the specimen (crystallinity, density, and so forth). This can be accomplished by the use of the heaters in the diffusion
cells.
10. Sampling
10.1 The sampling units Film samples used for the determination of O GTR shall be representative of the quantity of product
materials for which the data are required, in accordance with Practice required. D1898. Care shall be taken to ensure that samples
are representative of conditions across the width and along the length of a roll of film.
11. Test Specimens
11.1 Test specimens shall be representative of the material being tested and shall be free of defects, including wrinkles, creases,
and pinholes, unless these are a characteristic of the material being tested. tested and included in the material description.
11.2 Average If required, the average thickness shall be determined to the nearest 2.5 μm (0.0001 in.), using a calibrated dial
gage (or equivalent) at a minimum of five points distributed over the entire test area. Maximum, minimum, and average values
shall be recorded. If this measurement may damage the specimen, it can be done after permeation has been tested.
NOTE 1—If a sample is fragile (such as a thin coating or unprotected metallization) the act of measuring the material might compromise or scratch the
barrier layer. For such samples, analyzing the material thickness AFTER transmission rate testing may be preferable.
11.3 If the test specimen is of an asymmetrical construction, the two surfaces shall be marked by appropriate distinguishing
marks and the orientation of the t
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