1、Designation: D 685 93 (Reapproved 2002)An American National StandardTechnical Association of Pulp andPaper IndustryStandard Method T 402Standard Practice forConditioning Paper and Paper Products for Testing1This standard is issued under the fixed designation D 685; the number immediately following t
2、he designation indicates the year oforiginal adoption or, 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.This standard has been approved fo
3、r use by agencies of the Department of Defense.1. Scope1.1 This practice defines the standard atmospheres fornormal preconditioning, conditioning, and testing of paper andpaper products, paperboard, fiberboard, and containers madefrom them. It also specifies procedures for handling thesematerials in
4、 order that they may reach equilibrium with therespective atmosphere.1.2 This practice does not include special conditioning andtesting atmospheres, such as those that attempt to simulatetropical or arctic environments.1.3 This standard does not purport to address all of thesafety concerns, if any,
5、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:D 585 Practice for Sampling and Accepting a Single Lot
6、 ofPaper, Paperboard, Fiberboard, and Related Product2E 171 Specification for Standard Atmospheres for Condi-tioning and Testing Flexible Barrier Materials23. Significance and Use3.1 The preconditioning requirement is important becausephysical properties of a sample at 50 % relative humiditydepend u
7、pon whether the sample is brought to 50 % from ahigher or lower relative humidity. A detailed discussion of theimportance of preconditioning may be found in Annex A1.3.2 The conditioning and testing atmospheres are importantbecause both temperature and relative humidity have signifi-cant effects on
8、the physical properties of paper and board. Amore detailed discussion of the importance may be found inAnnex A2.4. Standard Atmospheres4.1 Preconditioning Atmosphere10 to 35 % relative hu-midity and 22 to 40C (see Annexes).4.2 Conditioning Atmosphere50.0 6 2.0 % relative hu-midity and 23.0 6 1.0C.4.
9、3 Testing AtmosphereSame as 4.2.NOTE 1It is important to distinguish between the overall limits of thetemperatures within which conditioning and testing may be carried outand the limits within which the temperature must be maintained in orderto maintain the specified relative humidity limits; that i
10、s, the closetemperature tolerance of 61C required in 4.2 and 4.3 will not in itselfensure the close relative humidity requirement of 62 % relative humidity,as a sudden change of 1C when at 23C and 50 % relative humidity willchange the relative humidity about 5 to 6 %.5. Apparatus5.1 Preconditioning
11、ChamberA room or cabinet in whichsample sheets or specimens may be individually exposed tocirculating air at the preconditioning relative humidity andtemperature.NOTE 2For smaller sheets or specimens, the required preconditioningmay be achieved easily with a simple cabinet, if no other means areavai
12、lable. If this cabinet is operated in a room maintained at 50 % relativehumidity and 23C and so designed that room air is drawn through it, andif the air entering and in the cabinet is heated to a temperature of 39 61C, the relative humidity in the cabinet will be in the required range (thatis, 20 6
13、 3 % relative humidity). Commercially available forced-ventilation “ovens” should prove satisfactory. Input air to the oven shouldbe drawn from the standard room, output should be vented outside of thestandard room.5.1.1 For many papers and boards, approximately the samepreconditioning moisture cont
14、ent obtained by the above pro-cedure may be achieved by using a sealed cabinet operated in1This practice is under the jurisdiction of ASTM Committee D06 on Paper andPaper Products and is the direct responsibility of Subcommittee D06.92 on TestMethods.Current edition approved Sept. 15, 1993. Publishe
15、d November 1993. Originallyapproved in 1942. Last previous edition approved in 1992 as D 685 92a.2Annual Book of ASTM Standards, Vol 15.09.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.a room maintained at 23 6 1C and using a satur
16、ated solutionof lithium chloride (LiCl) to obtain a relative humidity of about12 to 13 %.5.1.2 For larger rooms needed for preconditioning sealedcontainers and large sheets, the required low relative humiditymay be achieved by drawing air over a refrigerator expansioncoil operating at a few degrees
17、above freezing temperature.5.2 Conditioning and Testing ChamberOne or morerooms or cabinets in which sample sheets or specimens may beindividually exposed to circulating air at the conditioningrelative humidity and temperature, and then tested under thesame conditions.NOTE 3The required relative hum
18、idity (50.0 6 2.0 %) and tempera-ture (23.0 6 1.0C) are difficult to achieve and therefore careful attentionmust be given to the design, evaluation, and maintenance of the “standardroom.”5.3 HygrometerAny instrument that can indicate directlyor indirectly the relative humidity of the air with a cali
19、bratedaccuracy of 60.5 % relative humidity.5.4 ThermometerEither the dry bulb of a psychrometer(that is, a hygrometer of the wet- and dry-bulb type) or aseparate thermometer of any convenient design. If a separatethermometer, it should be graduated to 0.2C or closer withscale errors not exceeding th
20、ese values. (Psychrometer ther-mometers must be graduated and correct to 0.1C or closer andcarefully matched to each other to give the required accuracyand repeatability in the measurement of relative humidity.)6. Procedure6.1 Obtain and preserve the sample in accordance withPractice D 585. In parti
21、cular, avoid exposure of the sample todirect sunlight, to extremes of temperature, and, to relativehumidities above 58 % (see Annex A1). If the sample is to beheld for some time before testing, preserve it at a temperaturebelow 25C and relative humidity below 58 %, but not below10 % as the paper may
22、 curl or cockle and change in otherrespects.NOTE 4It has been reported that low-temperature storage below 10Cslows aging effects. Samples should be protected against condensation.6.2 Cut the specimens from a sample where critical dimen-sions are involved only after conditioning the sample. Wherether
23、e are no critical dimensions, the specimens may be cutbefore preconditioning or conditioning.6.3 If shipping containers are to be sealed with aqueousadhesives, make the seal prior to preconditioning.6.4 Expose the sample sheets or specimens to the precon-ditioning atmosphere so that both surfaces of
24、 single sheets andexterior surfaces of laminated products or sealed containers arefreely exposed. This is best achieved by suspending them fromoverhead or supporting them on a wire grid or rack.6.5 Precondition the sample sheets or specimens by expos-ing them as specified in 6.4 to the preconditioni
25、ng atmosphere.Precondition for a minimum of 24 h, unless a lesser time hasbeen found to give satisfactory results.NOTE 5For preconditioning apparatus of ample capacity and aircirculation, the following preconditioning times have usually been foundsatisfactory: single sheets of paper, less than 1 h;
26、liners corrugatingmedium, chip board, box board, 1 to 2 h; corrugated and solid fiber boardin sheet form, 5 to 10 h; sealed boxes and shipping containers, 12 to 16 h;specially treated water vapor resistant papers and boards, 24 h and more.NOTE 6If the sample is to be stored for some time after preco
27、ndi-tioning, store at a temperature below 25C and a relative humidity below40 % but not below 10 %.6.6 Condition the sample sheets or specimens by exposingthem as specified in 6.4 to the standard conditioning atmo-sphere for a sufficient time for them to come into equilibriumwith the atmosphere. Det
28、ermine that equilibrium has beenobtained by weighing the sheets or specimens at time intervalswhich increase roughly geometrically. Plot the weight againstlog time (that is, on semilogarithmic paper); the desiredequilibrium exists when the plotted curve becomes essentiallyparallel to the time axis.N
29、OTE 7With good air circulation and ample capacity, a conditioningperiod of4hisusually sufficient for paper of ordinary weight andcomposition. A minimum time of exposure of 5 to 8 h will be required forboards, and unsealed boxes, with a minimum time of 16 h or more forsealed fiberboard boxes, and muc
30、h longer periods for boards of heavysubstances and specially treated water-vapor resistant papers (for example,a minimum of 72 h for wax treated containers).6.7 Handle the preconditioned and conditioned sheets orspecimens as little as possible; especially avoid touching orbreathing on test areas.6.8
31、 Test the specimens in the standard testing atmosphere.7. Report7.1 The report shall include the following:7.1.1 Temperature, relative humidity, and total time of:7.1.1.1 Preconditioning,7.1.1.2 Conditioning before testing,7.1.2 Minimum and maximum temperature and relativehumidity during testing, an
32、d7.1.3 Any variations in procedure from this practice.8. Precision and Bias8.1 No statement is made about either the precision or thebias of the practice since it merely states the environmentalconditions under which paper tests are to be carried out. Theycould affect the precision and bias of the t
33、est methods, but sucheffects are reflected in the precision and bias statement appear-ing in the individual test method.9. Keywords9.1 conditioning; paper; paper products; reconditioning;standard atmosphereD 685 93 (2002)2ANNEXES(Mandatory Information)A1. IMPORTANCE OF PRECONDITIONINGA1.1 The physic
34、al properties of a sample at 50 % relativehumidity depend on whether the sample was brought to 50 %from higher or lower relative humidities. This “humidityhysteresis effect” is 5 to 25 % of the test value for manyphysical properties. For example, a hysteresis effect of 1.5 %moisture content (or 25 %
35、 of the test value of 6 % moisturecontent) is typical. Preconditioning on the dry side within therange specified will avoid most of the hysteresis effect andresult in the moisture content of a given sample beingestablished within 0.15 % when the sample is later conditionedto 50 % relative humidity a
36、nd 23 C. Conditioning down to50 % gives most papers a moisture content very nearly thesame as conditioning up to 60 %.A1.2 For the sake of obtaining close interlaboratory agree-ment, especially on physical properties, a specified precondi-tioning procedure is necessary but not always sufficient. Whi
37、lepreconditioning practically eliminates the hysteresis effect, ithas little influence on strain relaxation effects. The latterdepend on the entire previous moisture history of the sample,especially on the conditions of initial drying and tension, andon the duration and degrees of subsequent excursi
38、ons to highhumidities (that is, above about 58 % relative humidity).Consequently, for very close interlaboratory agreement astandardized procedure for handling the sample from manu-facture to testing is required.A1.3 For mill control and similar intra-laboratory purposes,the preconditioning step may
39、 often be eliminated. For someproperties and materials, preconditioning may not be neces-sary, either because of the smallness of the humidity hysteresiseffect or because of lower test accuracy requirements.A2. IMPORTANCE OF TEMPERATUREA2.1 A tolerance of 1.0C has been adopted in a number ofcountrie
40、s. It is recommended along with 62 % relative humid-ity, by Specification E 171 and by the technical committee,ISO/TC 125 on Enclosures and Conditions for Testing, when-ever close tolerances are required, as in paper and boardtesting. Both temperature and relative humidity have signifi-cant effects
41、on the physical properties of paper and board. Forsome properties of paper and board (for example, MD tensileand CD stretch) a change of 1C may have nearly as mucheffect as a change of 2 % relative humidity. For synthetic fibersand plastic laminates the temperature effect may be greaterthan the rela
42、tive humidity effect.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringemen
43、t of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or f
44、or additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views know
45、n to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 685 93 (2002)3
