ASTM_C_1520_-_02_2015e1.pdf

Designation:C152002(Reapproved 2015)1Standard Guide forPaintability of Latex Sealants1This standard is issued under the fixed designation C1520;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.1NOTEDuplicate wording was deleted in 18.1 in July 2015.1.Scope1.1 This guide describes the practical considerations thatmay be used to determine the compatibility of a paint orcoating to be applied over a latex sealant or caulk.It evaluatesthe appearance and not the performance characteristics of thecoated or painted joint.1.2 The committee with jurisdiction over this standard is notaware of any comparable standards published by other orga-nizations.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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 requirements prior to use.2.Referenced Documents2.1 ASTM Standards:2C717 Terminology of Building Seals and SealantsD1729 Practice for Visual Appraisal of Colors and ColorDifferences of Diffusely-Illuminated Opaque MaterialsD2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesE284 Terminology of Appearance3.Terminology3.1 DefinitionsRefer to Terminology C717 for definitionsof the following term(s)used in this guide:compatibility,cure,joint,latex sealant.Refer to Terminology E284 for definitionsof the following term(s)used in this guide:gloss.3.2 color changea change in either the observed(seePractice D1729)or measured color(see Test Method D2244)of a substance.3.3 crackinga failure resulting in a discontinuous film(ofpaint)or bead(of sealant).4.Summary of Practice4.1 This guide reviews many of the issues concerning thecompatibility of latex sealants with paint.While the focus ofthis guide is on latex sealants,the paint or coating may be ofany composition.5.Significance and Use5.1 The intent of this guide is to provide the reader withinformation concerning possible reasons for paint failureswhere the paint is used over a latex sealant.CONSIDERATIONS6.Temperature6.1 Since standard testing is usually performed at“roomtemperature,”about 22C,this would be considered the idealtemperature for application and curing.As the temperaturedeviates from this ideal,the“science”of drying changes in asmuch as lower temperature results in slower drying and fasterdrying occurs at elevated temperatures.7.Percent Relative Humidity7.1 In waterborne sealants,the humidity directly affects theability of the system to lose water.Standard testing is typicallydone at 50%RH,which allows for an acceptable evaporationrate.Temperature and humidity variations in climatic regionsand fluctuations through the application and cure will havesignificant impacts.8.Type of Paint8.1 The type of paint applied to the sealant has an effect onhow well it may handle dimensional changes,adhere to thesealant or dry during the curing of the sealant.Paints madefrom more flexible resins(low Tg)with low pigment volume1This guide is under the jurisdiction ofASTM Committee C24 on Building Sealsand Sealants and is the direct responsibility of Subcommittee C24.10 onSpecifications,Guides and Practices.Current edition approved June 1,2015.Published July 2015.Originally approvedin 2002.Last previous edition approved in 2010 as C1520-02(2010).DOI:10.1520/C1520-02R15E01.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 content(PVC)(PVC CPVC)will withstand the mostchange while a hard resin(high Tg)at high PVC will be theleast forgiving.Broadly speaking,high gloss,interior paintsrepresent the former while interior flat paints represent thelatter.9.Type of Sealant9.1 The sealant will have an effect on adhesion of the paintfilm,the degree of change in geometry of the paint film andchanges in color and gloss.However,generally speaking,thesechanges are difficult to quantify by the type and quality ofsealant.10.Cure Time10.1 The degree of sealant cure may affect the time to paint,the compatibility of the applied paint with the sealant,and thedry time of the applied paint.An uncured sealant may reactwith the paint ingredients.Cracking of the paint film may occurwhen the sealant is painted before curing of the sealant bead iscomplete due to subsequent shrinkage of the underlyings