DIN-53380-3-1998- standard

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Information about DIN-53380-3-1998- standard
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Published on July 12, 2016

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slide 1: DEU丁SCHENORM July 1998 Determining the gas transmission rate of plastic film sheeting and mouldings by the carrier gas method DIN 53380-3 ICS 83 .140.10 83 .140 .99 Descriptors: Plastics film sheeting plastic mouldings testing gas transmission rate . PrOfung von Kunststoffen -巴estimmung der Gasdurchlassigkeit -丁eil 3: Sauerstoffspezifisches Tragergas­ Verfahren zur Messu ng an Kunststoff “Folien und Kunststoff-Formteilen In keeping with current practice in standards published by the Interational Organization for Standardiza­ tion ISO a comma has been used throughout as the decimal marker. c。ntents Page Page Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 8.7 Load resistor . . . . . . . . . . . . . . . . . . . . . . . . 6 8.8 Voltage recorder . . . . . . . . . . . . . . . . . . . . . 6 1 Scope ..... 2 Normative references . . . . . . . . . . . . . . . 2 9 Checking the sensor . . . . . . . . . . . . . . . . . . 6 3 Concepts ... 3.1 Area-related oxygen transmission rate 3.2 Volume-related oxygen transmission 2 10 Calibration constant . . . . . . . . . . . . . . 6 2 rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 11 Spe cimen preparation . . . . . . . . . . . . . . . 7 11 .1 Film and sheeting . . . . . . . . . . . . . . . . . . . 7 11 .2 Holl。w bodies . . . . . . . . . . . . . . . . 7 11 .3 Number of specimens . . . . . . . . . . . . . . . 7 3.3 Length-related oxygen transmission rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 Designati 。n. 5 Principle . 5.1 Film or sheeting 5.2 Hollow-bodies 6 Reagents .. 6.1 Carrier gas ... 6.2 Oxygen and oxygen-gas mixture .. 6.3 Vacuum grease . 6.4 Adhesives 7 Apparatus 2 12 Testing of film and sheeting . . . . . . . . 7 12.1 Diffusion cell . . . . . . . . . . . . . . . . . . . . . . . 7 3 12.2 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 12.3 Determinin g the zero level . . . . . . . . 8 3 12.4 Determining the oxygen transmission 3 rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 龟 12.5 Film or sheet ing having a high oxygen 3 transmission脚 8 3 13 Testing hollow bodies . . . . . . . . . . . . . . . . 8 3 13.1 Closed bodies . . . . . . . . . . . . . . . . . . . . . . 8 4 13.2 Open bodies . . . . . . . . . . . . . . . . . . . . . . . 10 13.3 Testing of tubes . . . . . . . . . . . . . . . . . . . . 10 8 Components of difusion cells . . . . . . . . . . 5 8.1 Joints . . . . . . . . . . . . . . . . . . . . . . . . 5 8.2 Humidification components . . . . . . . . 5 8.3 Components for removal of oxygen from 14 Evaluation .......................... 11 14.1 Area-related oxygen transmission rate . . 11 14.2 Volume-re lated oxygen transmission rate ............................... 11 carrier gas . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.4 Fl。wmeter . . . . . . . . . . . . . . . . . . . . . 5 8.5 Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.6 Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 14.3 Length-related oxygen transmission rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 15 Test report ......................... 11 Continued on pages 2 to 11 . Translation by DIN-Sprachendienst . In case of doubt the German-language original should be consulted部the authoritative text. © No part o this 甘 nslation may be re阳odu四d without the M。r permi部iono DIN Deutches lnstitut fur Normung 且以 , Berlin. Beuth Verlag GmbH D 10772 Berlin has the exclusive right of sale for German Standa时sρ/N-Normen. Ref . No . DIN 533 80- 3: 1998 -07 English price group 08 Sales No. 0108 11.99 www.lab -men .com slide 2: Page 2 DIN 53380-3 : 1998-07 Foreword This standard has been prepared by Technical Committee Kunststoff-Folien und kunststoffbeschichtete Flachen- gebilde Kunstleder allgemeine Eigenschaften of the Normenausschuß Kunststoffe Plastics Standards Com- mittee. It is based on ASTM D 3985-95 but unlike the ASTM Standard its application is not limited to film and sheeting and it also covers plastic hollow bodies such as packing containers and tubes. Details of humidifying the carrier gas have also been included. 1 Scope The method specified in this standard serves to determine the oxygen transmission rate permeability to pure oxygen or oxygen gas mixtures e.g. air of plastic film and sheeting as defined in DIN 16922 and plastic hollow bodies e.g. packaging containers plastic tubes thereby enabling their suitability for packaging and engineer- ing applications to be assessed. The method can be used to determine transmission rates ranging from about 005 cm3/m2 . d . bar to 1 O00 cm3/m2 . d . bar for film and sheeting and from about 00005 cmVd . bar to 1 O cmVd . bar for hollow bodies where d denotes a day as a unit of 24 hours. 2 Normative references This standard incorporates by dated or undated reference provisions from other publications. These norma- tive references are cited at the appropriate places in the text and the titles of the publications are listed below. For dated references subsequent amendments to or revisions of any of these publications apply to this standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. DIN 1343 Reference conditions standard conditions and standard volume - Concepts and values DIN 16922 Classification of flexible sheeting produced using plastics DIN 50008-1 Artificial climates in technical applications - Controlled atmosphere over saturated salt solutions and glycerol solutions DIN 53370 Determination of plastic film and sheeting thickness by mechanical scanning ASTM D 3985-95 Standard test method for oxygen gas transmission rate through plastic film and sheeting using a coulometric sensor 3 Concepts 3.1 Area-related oxygen transmission rate For flat specimens of a constant thickness such as film or sheeting the area-related oxygen transmission rate is the volume of oxygen at standard temperature and pressure’ which passes through the specimen per unit area time and oxygen partial pressure. 3.2 Volume-related oxygen transmission rate For hollow bodies with an unknown surface area or a varying wall thickness the volume-related oxygen transmission rate is the volume of oxygen at standard temperature and pressure’ which passes through the specimen per unit time and oxygen partial pressure. 3.3 Length-related oxygen transmission rate For tubes the length-related oxygen transmission rate is the volume of oxygen at standard temperature and pressure’ which for given cross-sectional dimensions of the tube passes through the specimen per unit length of tube time and oxygen partial pressure. 4 Designation Designation of the method of determining the gas transmission rate by the carrier gas method S: Test DIN 53380 - S I See DIN 1343 for definition. --```````````````-`-`````--- slide 3: Page 3 DIN 53380-3 : 1998-07 5 Principle The oxygen transmission rate is determined under the conditions given below by measuring the quantity of oxygen which passes through the specimen. 5.1 Film or sheeting A specimen is mounted as a sealed barrier between the two chambers of a cell. One chamber is purged with a stream of nitrogen the other chamber contains oxygen. As oxygen passes through the specimen it is transported to a coulometric sensor where it produces an electrical current the magnitude of which is propor- tional to its concentration in the gas flow cf. clause 1 O. 5.2 Hollow bodies Nitrogen is passed directly through a hollow body whose exterior is exposed to oxygen. 6 Reagents 6.1 Carrier gas The carrier gas shall be dry nitrogen containing 05 YO to 3 YO V/V hydrogen and not more than 0Ol YO V/V oxygen. High-purity 999990 nitrogen may be used as the carrier gas in equipment as described in sub- clause 8.3. 6.2 Oxygen and oxygen-gas mixture The oxygen gas used shall be dry and shall contain not less than 995 YO V/V of oxygen or oxygen-gas mixtures preferably oxygen containing nitrogen free of carbon dioxide cf. subclause 8.6 and having an oxygen content known to within 0.5 YO. 6.3 Vacuum grease Vacuum grease shall be used to seal the diffusion cell. 6.4 Adhesives A gas-impermeable pore-free two-part adhesive shall be used when testing hollow bodies fast-curing adhe- sives based on methyl methacrylate or adhesives based on epoxy resin are recommended. --```````````````-`-`````--- slide 4: Page 4 DIN 53380-3 : 1998-07 Testing of film sheeting as in clause 12 Testing of hollow bodies as in clause 13 7 Testing of tubes as in subclause 13.3 AH v1 v2 K B G S D L T O L .el D T w AH It Connection to diffusion cell Valve Valve Metal tube filled with platinum catalyst or oxygen absorbent Gas washing bottle for humidifying the carrier gas where a low relative humidity of carrier gas is required Gas washing bottle for establishing specific humidities in the test gas Coulometric sensor Flowmeter and valve for setting carrier gas flow Load resistor Compressed gas steel cylinder containing carrier gas with pressure reducing valve and pressure gauge Compressed gas steel cylinder containing oxygen with pressure reducing valve and pressure gauge Figure 1 : Test apparatus schematic 2 Information on sources of supply is available from Normenausschuß Kunststoffe Burggrafenstraße 6 D-10787 Berlin. --```````````````-`-`````--- slide 5: Page 5 DIN 53380-3 : 1998-07 8 Components of diffusion cells 8.1 Joints All joints in metallic pipes carrying the gas shall be sealed so as to be gastight. Compression couplings have proved very suitable for this purpose. 8.2 Humidification components One of the methods described below shall be used to establish specific humidities in the test gas. 8.2.1 The gas to be humidified shall be passed through saturated salt solutions such as those described in DIN 50008-1 by which a standard atmosphere with relative humidities of 12 33 53 75 85 and 93 YO for example at 23 "C is produced. Gas washing bottles of about 250 cm3 capacity and about one-third full of salt solution including the undissolved salt shall be used the surface area of the salt solution being not less than 15 cm2. The gas inlet shall be positioned below the surface of the solution but above the undissolved salt allowing the gas flow to be checked by observing the gas bubbles. 8.2.2 The gas to be humidified shall be passed through distilled water at a suitable temperature. At a test temperature of 23 "C this produces a relative humidity ranging from 22 YO to 1 O0 YO. A thermostat shall be used to keep the washing bottle at the saturation temperature for the required relative humidity which can be taken from a water vapour pressure table. 8.2.3 If tests are carried out for a prolonged period at a low relative humidity less than 50 YO at 23 OC the sensor cf. subclause 8.6 may dry out. To prevent this occurring a small gas washing bottle containing distilled water may be inserted in the carrier gas stream at the inlet to the sensor see figure 2 B. Since the volume of this bottle and the take-up of oxygen in water cause a delay in the steady-state reading both the bottle volume and the quantity of water used shall be minimized. To prevent the specimen from being pressurized the end of the carrier gas line shall lie above the surface of the water. 8.3 Components for removal of oxygen from carrier gas Before the carrier gas enters the diffusion cell it shall be passed through a metal tube K containing about 5 g of a 05 platinum or palladium catalyst on alumina which causes any residual oxygen to react with the hydrogen in the carrier gas to form water. If the carrier gas is pure nitrogen 9999 see subclause 6.1 the metal cartridge shall be filled with an oxygen absorbent. 8.4 Flowmeter A controllable flowmeter D having a range from 5 mi/min to 1 O0 mumin shall be used enabling the carrier gas flow to be set and monitored. 8.5 Valves Two four-way ball valves Vl V2 shall be used for switching the carrier gas and oxygen flow to either the diffusion cell or the sensor. 8.6 Sensor The oxygen which permeates the specimen shall be detected using an oxygen-sensitive coulometric sensor S with nickel cadmium and graphite electrodes saturated with potassium hydroxide solution. To prevent the potassium hydroxide solution from drying up humid carrier gas shall be employed since the response time of the sensor will be otherwise reversibly prolonged. However measurements can be carried out for a few days with dry carrier gas without damaging the detector. The oxygen molecules entering the detector react at the surface of the graphite cathode where each oxygen molecule captures four electrons in the following reaction: O +2 HO +4 e--4 OH- The OH ions then release four electrons as a result of reacting with the porous cadmium anode as follows: 2Cd+4OH--2CdOH+4e- If the detector is exhausted it can be regenerated by applying a countervoltage. The detector will be irreversibly damaged by carbon dioxide which converts the potassium hydroxide solution into potassium carbonate. NOTE: Other sensors can be used if they fulfil the following requirements: 1. the reading gives approximately 1 O0 YO of the oxygen injected 2. there is a linear relationship between the output signal and the amount of oxygen injected --```````````````-`-`````--- slide 6: Page 6 DIN 53380-3 : 1998-07 3. the range of indication is from 2 . 10-8 g O/h to 6 . 1 O-4 g O/h for a flow of 20 cm3/min 4. the sensor has no resistance up to a flow of about 60 cm3/min 5. the sensor is insensitive to moisture 6. no reaction occurs with hydrogen. 8.7 Load resistor The voltage drop shall be measured across a load resistor through which the current generated by the coulo- metric sensor flows. Typical values for this resistor are 503 Q and 503 Q giving a convenient ratio of output voltage to oxygen transmission rate in units of cm3/m2 . d or cmVd in the case of hollow bodies. 8.8 Voltage recorder A multiple range strip chart recorder shall be used to measure the voltage drop across the load resistor. The recorder shall be capable of measuring voltages ranging from 0l mV to 50 mV at a resolution of 1 pV and shall have an input impedance of not less than 5 kQ. An equivalent electronic display or evaluation system may also be used. 9 Checking the sensor In principle four electrons are produced by the coulometric cell for every oxygen molecule. In practice the detectors generally achieve an approximately 1 O0 YO conversion of the oxygen molecules injected but become less effective if a critical flow of carrier gas is exceeded. The detector may give false readings because of ageing exposure to carbon dioxide the electrolyte drying up or because of oxygen breakthrough and shall therefore be checked at regular intervals. A known quantity of oxygen can be fed to the sensor via an inlet valve or using a gastight syringe. The sensor signal peak shall be integrated and the quantity of oxygen recorded shall be compared with that injected. The cause of any errors exceeding 5 YO shall be identified and if necessary the sensor shall be replaced. Another very accurate method of checking the sensor is that of water electrolysis. This involves allowing the carrier gas to flow through an electrolysis vessel in which water is being decomposed electrolytically. The oxygen produced during electrolysis is fed into the sensor and generates a current equal to the current con- sumed in electrolysis. 1 O Calibration constant For a specimen having an oxygen transmission rate of 1 O0 cm3/m2. d . bar and a test area of 1 O0 cm2 a standard oxygen volume of 1 cm3 shall be fed to the sensor over a period of 24 hours with an oxygen pressure difference of 1 bar between the sheet surfaces. Since each oxygen molecule generates four electrons 1 moi of oxygen yields a charge of 4 . 96485 A. s 386 . 1 O5 A . s according to Faradays law. It follows that 1 cm3 of oxygen 1/22393 moi flowing uniformly through the sensor over 24 h 86400s will generate a constant direct current of I 386 . 1 O5 A. s/moi . 1/22 393 moi 86400 s i 99 . i 0-4 A If this current is passed through a resistor and the resulting voltage drop is 1 mV the value of the resistor resistance R will be 1 O-3 V/199 . 1 O4 A 503 Q. The connection between resistor sensor voltage and the oxygen transmission rate of the specimen is shown in table 1. Table 1 : Oxygen transmission rate as a function of resistance and sensor voltage --```````````````-`-`````--- slide 7: Page 7 DIN 53380-3 : 1998-07 Accordingly the calibration constant for the oxygen transmission rate is as follows: QA 503 . 1 O4 cm3 . cm2 . Q/m2 . d . mV area-related QH 503 cm3 . Q/d . mV volume-related QL 503 cm3. m . Q/m . d . mV length-related. 11 Specimen preparation 11 .I Film and sheeting The specimens shall be of the sample material and shall be taken at points distributed uniformly overthe surface of the film. They shall be free of any flaws e.g. holes and show no signs of damage e.g. creases. The specimen thickness shall be determined using a DIN 53370 thickness measuring instrument. If the specimen is composed of several layers firmly bonded together ¡.e. it is a composite its surface shall be marked and the oxygen side and the relative humidity shall be reported. 11.2 Hollow bodies The hollow bodies used for testing in particular filled packaging containers shall be representative of the particular product. It is frequently necessary to empty the container before testing. This shall be done as carefully as possible ensuring that the opening made is no largerthan necessary and can easily be sealed using a two-part adhesive. 11.3 Number of specimens Not less than three specimens per orientation shall be tested. 12 Testing of film and sheeting 12.1 Diffusion cell i B Oxygen or carrier gas inlet T Thermometer wells OK Upper half of diffusion cell R O-ring VB S peci m en fi I m/s h eet i ng L Metal tubes fixed by soldering or screwing sealed UK Lower half of diffusion cell A Inlet/outlet of carrier gas Figure 2: Diffusion cell for film or sheeting schematic The diffusion cell in which the specimen is clamped consists of two metal halves of circular cross section. The exposed specimen area shall be 1 O0 cm2 or 50 cm2 and the total internal volume of the two halves of the cell shall be about 50 cm3 or 25 cm3. The temperature in each chamber shall be measured with separate thermom- eters. The O-ring seal between the two chambers and the clamped film shall be such that it forces the specimen against the flat rim of the lower chamber as close to its inner edge as possible. The lower chamber carrier gas side shall have a flat raised rim about 5 mm wide which since it is a critical sealing surface against the specimen shall be smooth and flat without scratches. The inside diameter of the lower chamber will determine the specimen area tested. In order to heat the diffusion cell to a temperature of 50 "C the lower chamber can be connected to a controllable electrical heater to ensure proper thermal conduction. --```````````````-`-`````--- slide 8: Page 8 DIN 53380-3 : 1998-07 When testing below ambient temperature or above 50 “C the diffusion cell shall be placed in a controlled- temperature cabinet. An alternative method is to design the two chambers so that the test temperature can be set using a liquid thermostat. 12.2 Procedure After the specimen has been mounted any leaks in the test arrangement shall be detected by flushing both sides of the specimen with nitrogen and the steady-state reading attained shall be recorded as the zero level. Oxygen shall then be supplied to one side of the specimen and the resultant steady-state value less the zero level value is taken to be the transmission rate. Keep the detector initially switched off using valve V1. Open the cell and apply a thin layer of vacuum grease around the raised rim of the lower half of the cell. Then place the specimen on the greased surface taking care to avoid wrinkles. Place the upper half on the lower half and depending on the cell design either screw or clamp both halves tightly together. Using valve V2 purge the air by passing carrier gas at a rate of 30 cm3/min to 60 cm3/min through the cell. After a few minutes reduce the rate to 15 cm3/min to 30 cm3/min for the subse- quent test. 12.3 Determining the zero level After flushing the cell for 30 minutes for example depending on the sample material divert the carrier gas from the lower half of the cell to the sensor by switching valve V1 see figure 3. Generally the sensor output as displayed by the recorder will then increase slightly indicating that oxygen is being flushed into the sensor along with the carrier gas most likely as a result of outgassing of the sample leaks in the system or a combination of the two. Wait until the sensor output current has stabilized. Thick samples may require a purge lasting a few hours or even overnight before they are oxygen-free during which time the sensor shall be bypassed using valveV1 except when checking the zero level. The zero level which should not exceed a value of 04 cm3/m2. d. bar will have been reached as soon as the reading has stabilized ¡.e asteady low value has been reached. If the value is higher locate the cause of the problem and eliminate it. Inadequate removal of oxygen from the carrier gas may lead to the zero level being dependent on the carrier gas flow cf. subclause 8.3. 12.4 Determining the oxygen transmission rate Once the zero level U has been established set valve V2 to the ‘test’ position thereby cutting off the nitrogen flow to the upper half of the cell and replacing it with oxygen. The sensor output voltage as indicated by the recorder will rise gradually after breakthrough and eventually stabilize cf. figure 3. Depending on the type of plastic and its thickness steady-state conditions will be reached at any time between seconds and many hours. During the measurement a simple leak test can be carried out to check that the specimen is free from pores and cracking by immersing the test gas outlet hose in a vessel containing water. The test gas pressure will be increased by a few millibars but if the specimen is pore-free there will be no change in the signal except for a short peak cf. figure 3 whereas there will be a permanent rise if pores are present. Equilibrium may be established in a short time for thin film orsheeting but thick samples may take several hours or days to reach a steady-state oxygen transmission rate. During this process pay particular attention to changes in the oxygen transmission rate of the specimen if extreme relative humidities such as O YO or 90 YO are employed. When testing plastics such as nylon 6 or polyvinyl alcohol several days may elapse before the pores have adjusted to the ambient humidity. In this case it is advisable to leave valve V1 in the ‘Sensor OFF’ position setting it to the ‘Sensor ON’ position only for short periods to check for further changes in the oxygen transmission rate. Once steady-state conditions have been attained and the respective voltage U determined calculate the area-related oxygen transmission rate qA using the equation given in subclause 14.1. 12.5 Film or sheeting having a high oxygen transmission rate Material with an oxygen transmission rate greater than 200 crn3/m2. d . bar will produce a high oxygen con- centration in the carrier gas possibly overloading the sensor and shortening its life. One way of avoiding this problem is to use nitrogen/oxygen mixtures such as air or commercially available test gases with an even lower oxygen concentration allowing for this in the evaluation. Another way of reducing the oxygen concentration in the test gas is to use a diffusion cell having a smaller test area and to cover most of the specimen surface by bonding metal foil to it cf. subclause 6.4. 13 Testing hollow bodies 13.1 Closed bodies Packages in which the contents are sealed on all sides against the ambient atmosphere are generally consid- ered to be closed hollow bodies. It will usually be necessary to remove the contents before testing. Exercise extreme care in doing this so that no damage is caused to the sample which could produce incorrect results. As a rule the opening for removing the contents shall be made at a smooth easily accessible location since the effect of seams on the oxygen transmission rate is of special interest in packaging testing and it is therefore essential that they remain unaltered. --```````````````-`-`````--- slide 9: Page 9 DIN 53380-3 : 1998-07 After emptying the package seal the opening using a pore-free gas-impermeable adhesive see subclause 6.4 then bond the empty package to the device as shown in figure 4. Mount the glass or metal cylinder used as an enclosure on the flat lower section of the apparatus. The cylinder may be replaced by a plastic bag cf. figure 5 made of a material having a low gas transmission rate. The total area of its outlet opening shall not be more than a few square millimetres. For testing at temperatures other than ambient temperature place the devices shown in figures 4 and 5 in a controlled-temperature cabinet. Flushing the outside of the specimen with nitrogen in the systems described produces the zero level U which takes into account all the leaks in the test arrangement while flushing with oxygen gives a steady-state voltage U cf. figure 3. Calculate the oxygen transmission rate of the hollow body qH using the equation in subclause 14.2. 21 t E ai m f c .- m 5 S s" s 6 St t 4- Time in minutes - 1 2 Leak test 3 Switching from carrier gas to oxygen: zero level U Switching from oxygen to carrier gas: UE - U 4 Oxygen desorption from specimen 5 Sensor switched on 6 Sensor switched off 7 Breakthrough time Figure 3: Test arrangement for determining the oxygen transmission rate test of plastic film or sheeting schematic VB VB I S VB Specimen container Z C Glass or metal cylinder B Oxygen/carrier gas inlet K Opening for removing contents sealed after re- moval Adhesive seal between carrier gas inlet and outlet tubes and container Figure 4: Test arrangement for measuring the oxygen transmission rate of closed packaging containers schematic A F Vacuum grease L Gastight solder joint between carrier gas tubes and baseplate S Baseplate and legs A Carrier gas inlet and outlet P Plastic bag Figure 5: Test arrangement for measuring the oxygen transmission rate of closed packaging containers using a plastic film bag schematic --```````````````-`-`````--- slide 10: Page 1 O DIN 53380-3 : 1998-07 X A Y M L VB Figure 6: Test arrangement for measuring the oxygen transmission rate of open hollow bodies schematic See figure 4 for key to symbols Length of tube section tested E Coupling piece Carrier gas inlet and outlet N Rubberseal Metal ring J Specimen tube section Metal or glass tube B Oxygen or carrier gas inlet Gastight solder joint between plug and carrier gas tube Figure 7: Test arrangement for measuring the oxygen transmission rate of tubes schematic 13.2 Open bodies Open hollow bodies are products having at least one opening examples being plastic bottles and thermoformed plastic dishes for packaging purposes and not yet sealed with a lid. Before testing the openings in these containers shall be sealed by bonding to them suitable sheets of 1 O0 pm thick aluminium foil using a two-part adhesive. After the adhesive has cured the containers may be regarded as closed packages cf. subclause 13.1. Alternatively an open dish or beaker may be bonded to the baseplate S in the test arrangement shown in figure 4 cf. figure 6. See subclause 13.1 for testing at temperatures other than ambient temperature and for determining the oxygen transmission rate. 13.3 Testing of tubes Solder metal plugs to the ends of the carrier gas tubes to be tested cf. figure 7 through which the carrier gas can be fed. The plugs shall be tapered by about 2" and their external diameter shall be such that they can be pressed tightly into the tube. Before inserting the plugs into the tube apply a film of vacuum grease to them and place metal rings each about 5 mm wider than the tube over the ends of the tube to ensure a firm contact. Place a metal or glass tube having an inside diameter about 1 O mm larger than that of the specimen over the tube being tested as shown in figure 7. Position rubber pieces between the ends of the metal/glass tube and the specimen to provide a seal. The space between may be flushed with nitrogen or oxygen using the inlet and outlet. Flushing with nitrogen produces the zero level U which takes into account all the leaks in the test arrangement while flushing with oxygen gives the steady-state voltage U for the length of tube section tested. Use the equation in subclause 14.3 to calculate the oxygen transmission rate per unit length q4. For testing at temperatures other than ambient temperature cf. subclause 13.1 place the test arrangement in a controlled- temperature cabinet. slide 11: Page 11 DIN 53380-3 : 1998-07 14 Evaluation Calculate the oxygen transmission rates using the following equations. 14.1 Area-related oxygen transmission rate U - U. QA. 1 O0 in cm3/rn2. d . bar qA A . R . o2 Pamb where U U A QA R Pamb is the steady-state voltage in mV is the zero-level voltage in mV is the test area of the specimen in cm2 is the calibration constant in cm3. cm2. Q/m2 . d . mv is the resistance of the resistor in Q is the atmospheric pressure in bar is the percentage by volume of oxygen in the test gas. o2 14.2 Volume-related oxygen transmission rate U - U. QH. 1 O0 qH in cm3/d . bar O2 amb where QH is the calibration constant in cm3 . Q/d . mV. 14.3 Length-related oxygen transmission rate where X QL is the length of the tube section tested in m is the calibration constant in cm3. m . Q/m . d . mV. 15 Test report The test report shall refer to this standard and include the following details: a type and description of the product tested b composition and relative humidity of the oxygen gas c relative humidity of carrier gas d orientation of specimen and relative humidity in the case of composite materials e thickness of specimen mean f temperature of diffusion cell g oxygen transmission rate individual values and mean calculated using equation l 2 or 3 h any deviation from this standard i date of testing. --```````````````-`-`````--- Labmen instrument Limited Tel :00852-30623001 Fa x:00852-31828558 Email : sale lab -men .com Site : www.lab -men .com www.lab -men .com Mail : sale lab -men .com info lab -men .com Skype : lormanled

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