ASTM_D_5725_-_99_2003.pdf

Designation:D 5725 99(Reapproved 2003)An American National StandardStandard Test Method forSurface Wettability and Absorbency of Sheeted MaterialsUsing an Automated Contact Angle Tester1This standard is issued under the fixed designation D 5725;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.INTRODUCTIONThe property of a liquid to adhere to,or“wet”,a sheeted surface,or to be absorbed by that surface,or both,is important in many aspects of paper manufacturing and converting,as well as in the end-useapplications of many converted paper products.Examples include,but are not limited to,the absorption of water or other liquid by an absorbentstructure(such as an absorbent tissue or wipe);the adhesion of an ink to a polymer film or a coatedor uncoated paper(such as a packaging or wrapping material);the adherence of a polymer film orsizing material to a paper substrate in a laminate or coated structure;the adhesion of a pressuresensitive tape to a release paper;the adhesion of a film to a paper substrate in a composite structure(such as a diaper or other composite structure);and the non-wetting or non-absorbency,or both,of abarrier paper.The wetting or sorptive behavior between a liquid and a particular sheeted substrate is dependent,at least in part,upon the relationship of the surface energy(tension)of the liquid and the surfaceenergy of the substrate.The theoretical relationship of these energies is complex,and the differentmathematical models which have been proposed for adhesion,wettability,and sorption are beyond thescope of this test method,but may be found in standard texts in these areas.In many cases,however,the contact angle of the fluid which will be in contact with the substrate,or the contact angle of a liquidof known surface tension,when placed in contact with a substrate of interest,is used to understandor predict in-process or end-use results of a particular printing,adhesion,or sorptive application.Contact angle measurements as described in Test Method D 724 or Canadian Pulp and PaperAssociation CPPA F.3H have been used to study and define the printability relationship between an(aqueous)ink and a paper at the water/paper interface.TAPPI T 552 and Test Method D 2578 use asomewhat different,semi-quantitative approach to provide information regarding the energy relation-ship between a polymer film and a nonaqueous liquid,the test end-point being the place where thecontact angle between a liquid of known surface tension and the test specimen approaches zero underthe conditions of the test.The procedure presented in this test method is a simple,completely automated approach to contactangle measurement applicable to a wide range of sheeted materials and liquids where interfacialcontact angles range from near zero to near 180 degrees.The automated procedure shows increasedprecision and greater ease in use than manual procedures.1.Scope1.1 This test method measures the contact angle of a testliquid in contact with a flat specimen of a film or a papersubstrate under specified test conditions.This test method maybe used with any liquid of interest which is compatible with theequipment used,particularly with regard to liquid viscosity,tackiness,and vapor pressure(evaporation).This test methodmay be used with any substrate of interest,which can be cut todimensions compatible with the equipment used.1.2 For materials which sorb the test liquid under thespecified test conditions,the rate of change of the contact angleas a function of time may be significant,and may be deter-mined using procedures described in this test method.It is alsopossible to evaluate the sorptive properties of a surface,as the1This 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 March 10,1999.Published May 1999.Orginallypublished as D 5725-95.Last previous edition D 5725-97.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.remaining liquid volume on top of the specimen surface ismeasured as a function of time.1.3 The conditions required in this test method specifyreagent water as the test liquid when testing papers designed tobe absorbent,such as absorbent tissue grades.1.4 Conditions are specified for the testing of a wide rangeof papers considered to be of low absorbance or nonabsorbent,including release papers,sized,coated,or unsized papersdesigned for printing,writing,wrapping,and similar taskswhere the paper surface interaction with aqueous or solventbased inks or other aqueous or nonaqueous liquids is impor-tant.In such cases,test liquids other than reagent water,including writing and printing inks,