ASTM_D_779_-_03.pdf

Designation:D 779 03An American National StandardStandard Test Method forWater Resistance of Paper,Paperboard,and Other SheetMaterials by the Dry Indicator Method1This standard is issued under the fixed designation D 779;the number immediately following the 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 for use by agencies of the Department of Defense.1.Scope1.1 This test method covers the determination of the timerequired for water to pass through a specimen of paper.It isbased on the dry-indicator method of Carson(1-4)2andmodifications of it developed by Abrams(5)and Codwise(6-8).1.2 It is designed for use with materials that require arelatively short time to test(up to approximately 30 s),and hasbeen found useful in testing slack-sized papers.NOTE1For testing hard-sized paper and paperboard,see TAPPI TestMethod T 441.1.3 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.Referenced Documents2.1 ASTM Standards:D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,and Related Product3D 685 Practice for Conditioning Paper and Paper Productsfor Testing3E 122 Practice for Calculating Sample Size to Estimate,with a Specified Tolerable Error,the Average for a Char-acteristic of a Lot or Process42.2TAPPI Standards:T 441Water absorptiveness of sized(non-bibulous)paperand paperboard(Cobb test)5T 433 Water resistance of sized paper and paperboard(dryindicator method)53.Summary of Test Method3.1 This test method consists of bringing one side of the testspecimen in contact with water and finding the time requiredfor the water to pass through the specimen,as indicated by thedevelopment of color in an indicator powder consisting of amixture of water-soluble dye,sugar,and starch.The sugarserves the two-fold purpose of masking the color of theparticles of dye as long as they are dry,and of absorbing thetransuded moisture and holding it in close proximity to the dye.The starch increases the stability of the mixture.3.2 Five tests are made on each side of the paper andreported as two separate averages.4.Significance and Use4.1 The dry indicator used in this test method is so stronglyhygroscopic it will change color in a moderate-to high-humidity atmosphere without contacting liquid water.It willalso change in contact with liquid water.This test method,therefore,measures the combined effect of vapor and liquidtransmission(9).For test times up to approximately 30 s,liquidtransudation rate is dominant and this test method can beconsidered to measure this property.As test times exceed 30 s,the influence of vapor-transmission rate increases and this testmethod cannot be regarded as a valid measure of liquidresistance(sizing).4.2 This test method is of value in cases where paper or apaper container comes into contact with water on one face.4.3 This test method is sometimes not applicable to mate-rials containing large amounts of water-soluble components.5.Apparatus5.1 Any form of apparatus for applying the test may be usedthat fulfills the following conditions:1This test method is under the jurisdiction of ASTM Committee D06 on Paperand Paper Products and is the direct responsibility of Subcommittee D06.92 on TestMethods.Current edition approved April 10,2003.Published June 2003.Originallyapproved in 1944 as D 779 44T.Last previous edition approved in 1994 asD 779 94(98).Discontinued 1987 and reinstated 1989.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3Annual Book of ASTM Standards,Vol 15.09.4Annual Book of ASTM Standards,Vol 14.02.5Published in related material section of Annual Book of ASTM Standards,Vol15.09.Also available from the TechnicalAssociation of the Pulp and Paper Industry,Technology Park/Atlanta,P.O.Box 105113,Atlanta,GA 30348.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.5.1.1 One surface of the specimen is wetted uniformly at themoment the count of time is begun,5.1.2 The indicator on the opposite surface is continuouslyvisible,5.1.3 No moisture reaches the indicator except that whichpasses through the specimen from the wetted surface,and5.1.4 No moisture that does so reach the indicator escapesfrom contact with it.5.2 Float Arrangement(7)Fig.1 shows one apparatus thatfulfills the requirements of 5.1.It is made of a thin-walledaluminum pan approximately 5 in.(127 mm)in diameter and1 in.(25.4 mm)high,with a hole 2 in.(50.8 mm)in diametercut in the bottom.The surface is coated with paraffin orbeeswax to make