1、Designation: D 2684 95 (Reapproved 2005)Standard Test Method forPermeability of Thermoplastic Containers to PackagedReagents or Proprietary Products1This standard is issued under the fixed designation D 2684; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers procedures for determining thepermeability of thermopla
3、stic containers to packaged reagentsor proprietary products under specified conditions of exposure.The exposures used are intended to simulate the normal andelevated temperature-storage conditions that might be encoun-tered in end-use application.1.2 This test method is applicable only to those type
4、s ofcontainers designed to allow positive, leakproof closure.1.3 Two procedures are provided:1.3.1 Procedure A is specific to testing only with a standarddesign container. This procedure provides for determinationsof rate of weight loss (or gain) and for calculation of apermeability factor.1.3.2 Pro
5、cedure B applies to tests of all other containerdesigns. Permeability data by this procedure are expressed onlyin terms of rate of weight loss (or gain) for the particularcontainer tested.1.4 The values stated in SI units are to be regarded asstandard.NOTE 1There is no similar or equivalent ISO Stan
6、dard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referen
7、ced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 4976 Specification for Polyethylene Plastics Molding andExtrusion MaterialsD 1505 Test Method for Density of Plastics by the Density-Gradient TechniqueE 145 Specification for Gravity-Convection and Forced-Ventilat
8、ion Ovens3. Terminology3.1 Definitions:3.1.1 permeability factor, Ptthe permeability of a givenplastic to a given product at temperature t, in degrees Celsius,expressed in units of gcm/daym2, as determined by ProcedureA. The permeability factor under 23C test conditions, forexample, is signified by
9、the notation P23.3.1.2 Determination of Ptis based on an averaged wallthickness over the entire area of the container and an assump-tion that permeation rate is inversely proportional to thethickness. Precaution in the extent of allowable variations ofthese factors is recommended, and use of Ptshoul
10、d take intoconsideration that wall thickness of the containers varies, thatthe estimate of average thickness from density, area, andweight is not exact, and that permeability of the productthrough the plastic material may not be directly proportional tothe thickness.4. Summary of Test Method4.1 Test
11、 bottles are filled with the test product and, aftersealing, are exposed at 23C (73.4F) and 50C (122F)conditions for 28 days or longer. Measurements of weight aremade at intervals to determine the average rate of weightchange.5. Significance and Use5.1 With the proper precautions and background expe
12、rience,results can be useful for estimation of the loss of a packagedproduct through the walls of a container during shelf storage.The test is also useful for isolating the effects of a containerdesign and materials, and is applicable for development andresearch and for specification purposes.5.2 In
13、 the absence of adequate supporting data, extrapola-tions or correlations of results to conditions beyond those of thetest are not recommended because of possible product alter-ation, solvency, or chemical effects on the plastic, etc.5.3 Before proceeding with this test method, referenceshould be ma
14、de to the specification of the material being tested.Any test specimen preparation, conditioning, dimensions, ortesting parameters, or combination thereof, covered in the1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.2
15、0 on Plastic Products.Current edition approved July 15, 2005. Published August 2005. Originallyapproved in 1968. Last previous edition approved in 2001 as D 2684 - 95 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For
16、Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.materials specification shall take precedence over those men-tioned in t
17、his test method. If there are no material specifica-tions, then the default conditions apply.6. Apparatus6.1 Enclosure or room with provision for maintaining thestandard laboratory atmosphere of 23 6 2C (73.4 6 3.6F)and 50 6 5 % relative humidity, as defined by Practice D 618.6.2 Circulating-Air Ove
18、n, consistent with ovens in accor-dance with Specification E 145, capable of maintaining atemperature of 50 6 1C (122 6 1.8F) and an airflow rate of8.5 to 17.0 m3/min (300 to 600 ft3/min).The limitation of 25 ft3on oven size can be overlooked, provided all other require-ments are met.NOTE 2Only expl
19、osion-proof equipment with provision for adequateexhaust of vapors should be used for tests with potentially hazardous ortoxic products.NOTE 3Relative humidity variation can significantly affect perme-ability loss in many products, especially water-based products in variousthermoplastics. Therefore,
20、 the user may find it useful to equip the ovenwith a means to measure relative humidity and to record the same duringthe period of test.6.3 Balance, accurate to 0.01 % of the weight of testcontainer and contents.6.4 Container Seals, suitable heat-sealing laminate3andpolyethylene or other suitably li
21、ned screw-type closures forsealing the containers.6.5 Heat Sealer.6.6 Torque Wrench.7. Reagents and Materials7.1 The reagent or proprietary product as specified fortesting.8. Test Specimens8.1 The test specimen for Procedure A shall be the 4-ozcylindrical bottle design as specified in Fig. 1, having
22、 anominal external surface area of 154 cm2(23.8 in.2).8.2 The test specimen for Procedure B may be any thermo-plastic container, as specified or selected for test evaluation,provided it is designed to allow positive closure.8.3 For each procedure, a minimum of three specimens shallbe tested at each
23、temperature. Three additional specimens arerequired for Procedure A for determination of the plasticdensity.NOTE 4Trim and finish the containers, if needed, to ensure a smoothcontacting surface for positive seal.9. Conditioning9.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and
24、50 6 5 % relative humidity for not lessthan 40 h prior to test in accordance with Procedure A ofPractice D 618, for those tests where conditioning is required.In cases of disagreement, the tolerances shall be 61C(61.8F) and 62 % relative humidity.9.2 Test ConditionsConduct tests in the standard labo
25、ra-tory atmosphere of 23 6 2C (73.4 6 3.6F) and 50 6 5%relative humidity, unless otherwise specified in the test meth-ods. In cases of disagreements, the tolerances shall be 61C(61.8F) and 62 % relative humidity.10. Procedure A (Standard Container)10.1 With specimens taken from the sidewalls of thre
26、e ofthe containers, determine the average plastic density by TestMethod D 1505, or by an alternative method of equivalentaccuracy.10.2 For each test temperature, select a minimum of threecontainers. Weigh each when empty, without the closure. Alsoweigh the empty containers with their corresponding c
27、losuresand appropriately sized laminate pieces.10.3 Fill the containers to nominal capacity with the testproduct.10.4 Make a thorough check for any drippage or spill ofproduct on the outside surface of the containers. If any is noted,replace the container with a new specimen.10.5 Heat seal the conta
28、iners with the laminate (plastic toplastic), check for leaks, and then cap the containers withscrew-type closures, using sufficient torque to provide positiveseal. Avoid distorting the container when capping.NOTE 5One method of testing for a poor seal is to immerse an uprighttest container in a beak
29、er filled to the base of the cap with a liquid that willnot attack the plastic. When a vacuum of 15 in. Hg is applied to the entiresystem, a poorly sealed bottle will give off bubbles from the sealed area.NOTE 6Any deformation of the container during sealing may result ina volume change which will a
30、ffect the final test pressure. An applicationtorque of 1.7 Nm (15 lbfin.) has been found sufficient for the standardcontainer in Fig. 1.3One such laminate suitable for polyethylene containers, MIL-B-131C Class 2,a polyethylene-aluminum foil-paper laminate available from the Robertson Co.,Jamaica, NY
31、. Heat sensitive seals are also available from 3M Packaging SystemsDivision, 3M Center Building 220-8W-01, St. Paul, MN, 55144.NOTE 1Dimensions are in millimetres.FIG. 1 Standard Container for Permeability TestD 2684 95 (2005)210.6 Weigh the sealed containers.10.7 Unless otherwise specified, expose
32、one set of contain-ers in the Standard Laboratory Atmosphere, 23 6 2C (73.4 63.6F) and 50 6 5 % relative humidity, and another set in acirculating-air oven controlled at 50 6 1C (122 6 1.8F).Place the containers upright on an inert metal screen orperforated sheet support to allow air circulation. Pl
33、ace a traybeneath the container support to collect leakage of product, iffailure occurs. Provide enough spacing between the containersso they do not touch each other. Also, take precautions asnecessary to prevent any possible cross-contamination in thetest chamber from other agents.NOTE 7For certain
34、 relatively unstable or spoilable products, the useof elevated temperature exposures may not be applicable.10.8 Weigh the containers after 1 day, 7 days, 14 days, 21days, and 28 days. In certain cases, a steady rate of weightchange may be reached in either a shorter or longer period.Other intervals
35、can then be used. They should be regular andreported.10.8.1 If the weight change appears abnormal for any of thecontainers during exposure, inspect the containers to ensurethat a positive seal exists. If a leak is detected, retest with a newspecimen.10.8.2 Cool in the standard laboratory atmosphere
36、untilconsistent weighings are obtained. Resume oven exposurewithin 6 h from removal time.10.8.3 In elevated-temperature tests, rotate the locations ofthe specimens in the oven when re-exposing after each intervalto minimize possible bias due to variations of airflow andtemperature within the oven.10
37、.9 Calculation:10.9.1 Calculate the percentage weight loss or gain after agiven exposure time as follows:Weight loss at time x!,%5 Gu2 Gx!/Nu# 3 100 (1)Weight gain at time x!,%5 Gx2 Gu!/Nu# 3 100 (2)where:Gu= gross weight of unexposed bottle, closure, and con-tents, g,Gx= gross weight of exposed bot
38、tle, closure, and contents,g, andNu= net weight of unexposed test product in the bottle, g.10.9.2 Rate of Average Weight ChangePlot the weightchanges, GuGxfor losses or GxGufor gains, versus timein days on rectilinear graph paper. Draw the best straight linethrough the points, ignoring, if necessary
39、, points near thebeginning or end of the test period that deviate excessivelyfrom the best line through intermediate points. From the slopeof the line, determine the rate of average weight change, R,ingrams per day, as illustrated in Fig. 2. Note whether the changeis loss or gain.Weight change per d
40、ay, % 5 R/Nu! 3 100 (3)10.9.3 Permeability Factor (see 3.1)Calculate the perme-ability factors as follows:Pt5 RT/A (4)For Ptin metric units, gcm/daym2.R = rate of average weight change, g/day, from 10.9.2, andT = average bottle wall thickness, cm, calculated frombottle weight, area in cm2, and densi
41、ty of the bottlematerial, for example:T 5weight of bottle g!density g/cm3!3area cm2!(5)A = bottle surface area, m2.NOTE 8For Procedure A, where the standard 4-oz Boston RoundBottle is used (23.8-in.2area), the following equations can be used:To calculate Ptin metric units:Pt5RT/A 5 R g/day!3weight o
42、f bottle g!density g/cm3!32.358(6)11. Procedure B (Nonstandard Containers)11.1 Follow the procedure in 10.2-10.8.NOTE 9If not feasible to heat seal the container due to design, etc.,any other means for providing an equivalent, nonpermeable, leakproofclosure would be an acceptable alternative.11.2 Ca
43、lculation:11.2.1 Calculate the percentage weight loss or gain after agiven exposure time as detailed in 10.9.1.11.2.2 Calculate the rate of average weight change as shownin 10.9.2.12. Report12.1 Report the following information:12.1.1 Complete bottle and test product identification anddescription,12
44、.1.2 Complete closure identification and description.12.1.3 Exposure conditions,12.1.4 Calculated permeation data,12.1.5 Any occurrences of container leakage, failure, etc.,12.1.6 Date of test,12.1.7 Duration of test, and12.1.8 Regular weighing intervals.13. Precision and Bias13.1 Round-robin testin
45、g among six laboratories by Proce-dure A was performed with containers of Class 3 polyethylenein accordance with Specification D 4976, and a variety ofliquid reagents. Ptvalues ranged from 0.02 to about 200mgcm/daym2. Over this wide range, the standard deviationsof the results between laboratories i
46、ncreased with increasedvalues of Pt. For 18 levels of Pt, the interlaboratory coefficientsof variation remained relatively constant with the overallaverage being 14 %.13.2 Since there is no accepted reference method for thistest method, the bias of this test method cannot be determined.14. Keywords1
47、4.1 containers; permeability; plastic bottlesD 2684 95 (2005)3APPENDIX(Nonmandatory Information)X1. MIXED INCH-POUND METRIC UNITS AND CONVERSION FACTORSX1.1 For Ptin mixed inch-pound-metric units, gmil/day100 in.2.R = rate of average weight change, g/day, from 10.9.2,T = average bottle wall thicknes
48、s, mil, calculated frombottle weight, area in in.2, and density, for example:T 5weight of bottle g!31000 mil/in.!density g/cm3!316.39 cm3!3area in.2!(X1.1)A = bottle surface area in units of 100 in.2; for example, ifbottle surface area is 23.8 in.2, A = 0.238.NOTE X1.1The mixed inch-pound-metric uni
49、ts are not recommendedfor general use, but are included to establish a relationship with work thathas been previously accomplished in this area.X1.2 To convert Ptvalues between systems use the follow-ing equations:Pt(metric units) = 0.0394 Pt(mixed inch-pound-metricunits)Pt(mixed inch-pound-metric units) = 25.4 Pt(metric units)FIG. 2 Example PlotDetermination of Slope for Rate of Weight ChangeD 2684 95 (2005)4ASTM International takes no position respecting the validity of any patent rights asserted in connection wi
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