ASTMD5725-99

Designation:D 5725-99 (Reapproved 2003)An American National StandardINTERNATIONALStandard 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 ofrevision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon ()indicates an editorial change since the last revisionor 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 fi lm 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 fi lm 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 abamier 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 ofthe 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 defi ne 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 interfacialcontac