ASTM_D_2732_-_14_2020.pdf

Designation:D273214(Reapproved 2020)Standard Test Method forUnrestrained Linear Thermal Shrinkage of Plastic Filmand Sheeting1This standard is issued under the fixed designation D2732;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()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers determination of the degree ofunrestrained linear thermal shrinkage at given specimen tem-peratures of plastic film and sheeting of 0.76 mm(0.030 in.)thickness or less.This test method does not cover shrinkagefrom loss of solvent in some materials.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE1This standard and ISO 11501 address the same subject matter,but differ in technical content.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1204 Test Method for Linear Dimensional Changes ofNonrigid Thermoplastic Sheeting or Film at ElevatedTemperatureE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids2.2 ISO Standard:3ISO 11501 Determination of Dimensional Change on Heat-ing3.Terminology3.1 Definitions:3.1.1 unrestrained linear thermal shrinkage(free shrink orshrinkage)the irreversible and rapid reduction in lineardimension in a specified direction occurring in film subjectedto elevated temperatures under conditions where nil or negli-gible restraint to inhibit shrinkage is present.It is normallyexpressed as a percentage of the original dimension.4.Significance and Use4.1 As a result of the manufacturing process,internalstresses may be locked into the film which can be released byheating.The temperature at which shrinkage will occur isrelated to the processing techniques employed to manufacturethe film and may also be related to a phase transition in the baseresin.The magnitude of the shrinkage will vary with thetemperature of the film.4.2 Shrinkage of a particular material produced by a par-ticular process may be characterized by this test method bymaking measurements at several temperatures through theshrinkage range of the material.4.3 Following a characterization in a particular case,it isusually sufficient thereafter to measure shrinkage at only oneselected temperature for purposes of process or quality control,or both.5.Apparatus5.1 Constant-Temperature Liquid Bath,capable of control-ling accurately to 60.5C.5.1.1 The liquid for the bath should not plasticize or reactwith the specimens.Poly(ethylene glycol),glycerin,and waterhave been found to have wide applicability.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film,Sheeting,andMolded Products.Current edition approved April 1,2020.Published April 2020.Originallyapproved in 1968.Last previous edition approved in 2014 as D2732 14.DOI:10.1520/D2732-14R20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.15.2 ThermometerASTM Thermometer S5C-11 conform-ing to the requirements as prescribed in Specification E2251.5.3 Square Metal Stamp,100 by 100 mm,with engravedarrow indicating machine direction of film and stamp pad a