1、Designation: D2684/D2684M 15Standard Test Method forPermeability of Thermoplastic Containers to PackagedReagents or Proprietary Products1This standard is issued under the fixed designation D2684/D2684M; the number immediately following the designation indicates theyear of original adoption or, in th
2、e case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers procedures for determining thepermeability of thermoplastic c
3、ontainers 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 types ofco
4、ntainers 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 Procedure
5、 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 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. Thevalues
6、 stated in each system may not be exact equivalents;therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.NOTE 1There is no known ISO equivalent to this standard.1.5 This standard does not purport to addr
7、ess 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. Referenced Documents2.1 ASTM Standards:2D618 Practice
8、for Conditioning Plastics for TestingD4976 Specification for Polyethylene Plastics Molding andExtrusion MaterialsD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions:3.1.1 permea
9、bility 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 the notation P23.3.1.1.1 DiscussionDetermination of
10、 Ptis based on anaveraged wall thickness over the entire area of the containerand an assumption that permeation rate is inversely propor-tional to the thickness. Precaution in the extent of allowablevariations of these factors is recommended, and the user of Ptneeds to recognize that wall thickness
11、of the containers varies,that the estimate of average thickness from density, area, andweight is not exact, and that permeability of the productthrough the plastic material is, generally, not directly propor-tional to the thickness.4. Summary of Test Method4.1 Test bottles are filled with the test p
12、roduct and, aftersealing, are exposed at 23C 73.4F and 50C 122Fconditions for 28 days or longer. Measurements of weight aremade at intervals to determine the average rate of weightchange.1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of S
13、ubcommittee D20.19 on Film, Sheeting, andMolded Products.Current edition approved Sept. 1, 2015. Published September 2015. Originallyapproved in 1968. Last previous edition approved in 2010 as D2684 - 10. DOI:10.1520/D2684_D2684M-15.2For referenced ASTM standards, visit the ASTM website, www.astm.or
14、g, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C70
15、0, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 With the proper precautions and background experience,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 ef
16、fects of a containerdesign and materials, and is applicable for development andresearch and for specification purposes.5.2 In the absence of adequate supporting data, extrapola-tions or correlations of results to conditions beyond those of thetest are not recommended because of possible productalter
17、ation, solvency, or chemical effects on the plastic, etc.5.3 Before proceeding with this test method, refer to thespecification of the material being tested. Any test specimenpreparation, conditioning, dimensions, or testing parameters, orcombination thereof, covered in the materials specificationsh
18、all take precedence over those mentioned in this test method.If there are no material specifications, then the default condi-tions apply.6. Apparatus6.1 Enclosure or room with provision for maintaining thestandard laboratory atmosphere of 23 6 2C 73.4 6 3.6Fand 50 6 10 % relative humidity, as define
19、d by Practice D618.6.2 Circulating-Air Oven, consistent with ovens in accor-dance with Specification E145, 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
20、require-ments are met.NOTE 2The use of explosion-proof equipment with provision foradequate exhaust of vapors is recommended for tests with potentiallyhazardous or toxic products.NOTE 3Relative humidity variation can significantly affect permeabil-ity loss in many products, especially water-based pr
21、oducts in variousthermoplastics. For these purposes, it is recommended that the oven beequipped with a means to measure relative humidity and to record thesame during the period of test.6.3 Balance, accurate to 0.01 % of the weight of testcontainer and contents.6.4 Container Seals, suitable heat-sea
22、ling laminate3andsuitably lined screw-type closures for sealing 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 a
23、s specified in Fig. 1, having anominal external surface area of 154 cm223.8 in.2.8.2 Any thermoplastic container, as specified or selected fortest evaluation, can be used for Procedure B provided it isdesigned to allow positive closure.8.3 For each procedure, a minimum of three specimens shallbe tes
24、ted at each temperature. Three additional specimens arerequired for Procedure A for determination of the plasticdensity.8.4 If necessary, trim and finish the containers to ensure asmooth contacting surface for positive seal.9. Conditioning9.1 ConditioningCondition the test specimens at 23 62C 73.4 6
25、 3.6F and 50 6 10 % relative humidity for notless than 40 h prior to test in accordance with Procedure A ofPractice D618, for those tests where conditioning is required.In cases of disagreement, the tolerances shall be 61C61.8F and 65 % relative humidity.9.2 Test ConditionsConduct tests in the stand
26、ard labora-tory atmosphere of 23 6 2C 73.4 6 3.6F and 50 6 10 %relative humidity, unless otherwise specified in this testmethod. In cases of disagreements, the tolerances shall be61C 61.8F and 65 % relative humidity.10. Procedure A (Standard Container)10.1 With specimens taken from the sidewalls of
27、three ofthe containers, determine the average plastic density by TestMethod D1505, 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 and3One such laminate suitable for polyethylene contain
28、ers, MIL-B-131C Class 2,a polyethylene-aluminum foil-paper laminate available from the Robertson Co.,Jamaica, NY. 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
29、 for Permeability TestD2684/D2684M 152laminate pieces. Also weigh the empty containers with theircorresponding closures and appropriately sized laminatepieces.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 outsi
30、de surface of the containers. If any is noted,replace the container with a new specimen.10.5 Heat seal the containers 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 con
31、tainer when capping.NOTE 4One method of testing for a poor seal is to immerse an uprighttest container in a beaker 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
32、 the sealed area.NOTE 5Any deformation of the container during sealing may result ina volume change which will affect the final test pressure. An applicationtorque of 1.7 Nm 15 lbfin. has been found sufficient for the standardcontainer in Fig. 1.10.6 Weigh the sealed containers.10.7 Unless otherwise
33、 specified, expose one set of contain-ers in the Standard Laboratory Atmosphere, 23 6 2C 73.4 63.6F and 50 6 10 % 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
34、 circulation. Place 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.N
35、OTE 6For certain relatively unstable or spoilable products, the use ofelevated temperature exposures may not be applicable.10.8 Weigh the containers after 1 day, 7 days, 14 days, 21days, and 28 days. If a steady rate of weight change is reachedin either a shorter or longer period, other regular inte
36、rvals canthen be used and reported.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 After removal from the oven, cool the container inthe standar
37、d laboratory atmosphere until consistent weighingsare obtained. Resume oven exposure within 6 h from removaltime.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 andtemper
38、ature within the oven.10.9 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# 3100 (1)Weight gain at time x!,%5 Gx2 Gu!/Nu# 3100 (2)where:Gu= gross weight of unexposed bottle, closure, andcontents, g,Gx= gross w
39、eight of exposed bottle, 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 time indays on rectilinear graph paper. Draw the best straight linethrough the points, ig
40、noring, if necessary, 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
41、.Weight change per day, % 5 R/Nu! 3100 (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.where:R = rate of average weight change, g/day, from 10.9.2, andT = average bottle wall thickness, cm, calculated from bottleweigh
42、t, area in cm2, and density of the bottle material,for example:T 5weight of bottle g!density g/cm3! 3area cm2!(5)where:A = bottle surface area, m2.NOTE 7For 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 u
43、nits:Pt5RT/A 5 R g/day! 3weight of bottle g!density g/cm3! 32.358(6)11. Procedure B (Nonstandard Containers)11.1 Follow the procedure in 10.2 10.8.NOTE 8If not feasible to heat seal the container due to design, etc.,any other means for providing an equivalent, nonpermeable, leakproofclosure would be
44、 an acceptable alternative.11.2 Calculation: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 produc
45、t identification anddescription,12.1.2 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,D2684/D2684M 15312.1.7 Duration of test, and12.1.8 Regular weighing inter
46、vals.13. Precision and Bias13.1 Round-robin testing among six laboratories by Proce-dure A was performed with containers of Class 3 polyethylenein accordance with Specification D4976, and a variety of liquidreagents. Ptvalues ranged from 0.02 to about 200 mgcm/daym2. Over this wide range, the standa
47、rd deviations of theresults between laboratories increased with increased values ofPt. For 18 levels of Pt, the interlaboratory coefficients ofvariation remained relatively constant with the overall averagebeing 14 %.13.2 Since there is no accepted reference method for thistest method, the bias of t
48、his test method cannot be determined.14. Keywords14.1 containers; permeability; plastic bottlesAPPENDIX(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
49、,T = average bottle wall thickness, mil, calculated from bottleweight, 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 units are not recommendedfor general use, but are included to establish a relationship with work thathas been previously accomplished in this area.X1.2 To conve
