1、Designation: C1520 02 (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
2、 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 co
3、mpatibility 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-nizati
4、ons.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
5、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 Opaq
6、ue 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,
7、 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
8、 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 prov
9、ide 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 cur
10、ing. 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
11、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
12、 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 r
13、esponsibility 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 webs
14、ite, 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 State
15、s1content (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 adhe
16、sion 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 o
17、f 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 underlyingsealant. Addit
18、ionally, migration of sealant components to thebead surface may affect adhesion.11. Sealant Geometry/Tooling11.1 Use of a backing material usually helps to decreasesealant cracking and thereby also usually decrease paintfailure.12. Method of Paint Application12.1 The manner in which the paint is app
19、lied, that is, roller,brush or sprayer, may affect the thickness of the paint that isinitially applied. Some rollers and brushes, especially low costapplicators, may lose bristles or leave brush strokes or surfaceirregularities in the paint film, which may promote prematurefailures.13. Substrate Eff
20、ects13.1 The porosity, composition and cleanliness of the sub-strate affect the cure of both sealant and paint. A more poroussubstrate will wick away water or solvent and shorten the paintcuring period. A difficult to adhere to substrate, or one thatconsists of material containing low molecular weig
21、ht oils,plasticizers, etc., will affect film formation and wetting, andmay induce gloss and color change.14. Type of Construction14.1 This affects the substrates and amount of movementthat a paint/sealant system may be subjected to.15. Lot to Lot Variation15.1 A number of factors contribute to lot t
22、o lot variation inboth sealants and paints. Whenever changing either, it may beprudent to test compatibility.OBSERVATIONS16. Cracking16.1 This may be simple cracking of the paint film or maymanifest itself as a crack in the sealant. The degree and amountof cracking between the sealant and the paint
23、will affect theacceptability of this condition. Severe cracking of the sealantmay overwhelm the crack bridging ability of the paint film.17. Color Change17.1 This may be caused by the leaching of material fromeither the sealant or substrate into the paint and changing itsappearance. This may also be
24、 caused by the paint being moresusceptible to dirt pick-up, especially in areas where airbornedirt is prevalent.18. Gloss18.1 Plasticizer migration may cause the paint to develop ahigher gloss over time.19. Keywords19.1 cracking; latex sealant; paintASTM International takes no position respecting th
25、e validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard i
26、s subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International He
27、adquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This s
28、tandard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 02 (2015)12
