1、Designation: D7306 07 (Reapproved 2017)Standard Practice forTesting Low Temperature Film-Formation of Latex Paints byVisual Observation1This standard is issued under the fixed designation D7306; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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.1. Scope1.1 This practice specifies a laboratory procedure for evalu-ating the ability of a latex paint to
3、 form a uniform film free ofvisible defects at low temperatures.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
4、 theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization es
5、tablished 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:2D823 Practices for Producing Films of Uniform Thicknessof Pa
6、int, Varnish, and Related Products on Test PanelsD3793 Test Method for Low-Temperature Coalescence ofLatex Paint Films by Porosity Measurement (Withdrawn2012)33. Terminology3.1 Definitions:3.1.1 low temperature coalescence (LTC), nthe ability ofa latex paint to form a film at low temperatures, typic
7、ally4 6 2C (39 6 4F).4. Summary of Practice4.1 The paint, applicator and the test panel are allowed toequilibrate for at least4hat46 2C (39 6 4F). The test paintis applied to a part-sealed/part-unsealed drawdown chart andimmediately placed in a cold cabinet.4.2 After 18 h the panel is removed from t
8、he cold cabinetand evaluated for any cracking of the paint film.NOTE 1Temperature of film formation testing may be altered uponmutual consent of all parties involved.5. Significance and Use5.1 This practice can be used by paint formulators todetermine if a given paint has the ability to form a film
9、at lowtemperatures. This practice can be used as an aid for determin-ing coalescing solvent level required to form a good film. TestMethod D3793 compares the porosity of a film drawn down atroom temperature to another film drawn down and cured at lowtemperature.5.2 This practice provides no absolute
10、 information, ratherranking only of the selected series of paints.5.3 This practice can provide a pass-fail situation if knownacceptable and unacceptable paints are included in the test.6. Apparatus and Materials6.1 Vacuum Plate.6.2 Paint Test Chart with sealed and unsealed evaluationareas.46.3 Pain
11、t Applicator(s), typically to apply 3 and 10 mil wetfilm thickness of paint with higher thickness being moresevere.6.4 Cold Cabinet, maintaining 4 6 2C (39 6 4F) or adifferent temperature as agreed upon.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Mate
12、rials, and Applications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in 2007. Last previous edition approved in 2013 as D7306 07 (2013).DOI: 10.1520/D7306-07R17.2For referenced ASTM sta
13、ndards, 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.3The last approved version of this historical standard is referenced onwww.astm.org.4
14、Paint test charts selected for use should be from a sole supply across theexperiment to ensure accurate comparisons between test samples.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accor
15、dance 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.16.5 Instrument, to record relati
16、ve humidity (typically 20 to100 %).NOTE 2Variation in humidity can have impact on film formation.6.6 4X 12X Magnifying Glass,6.7 Test Paint.7. Procedure7.1 Place the applicator, paint, and test panel in a coldcabinet and equilibrate for 4 h at 4 6 2C (39 6 4F), or asagreed upon.7.2 Secure a paint te
17、st chart with sealed and un-sealed areason a vacuum drawdown plate.7.3 After mixing the paint sample, draw down the paintuniformly using a straight bar applicator as in Practices D823.7.4 Immediately place the panel into the cold cabinet.7.5 After 18 h, remove the panel for evaluation as outlinedin
18、8.2.NOTE 3This practice can be conducted at several thicknesses in orderto obtain a better understanding of low temperature film performance.Thicker films tend to increase the likelihood of cracking.NOTE 4Variations in airflow within the cold cabinet can affect results.8. Report8.1 Examine the dried
19、 film for continuity under a magnify-ing glass. Report the degree of cracking over the sealed surfaceand the unsealed surface. Disregard cracking on the peripheryof the dried film.8.2 Rating system for each surface should be as follows:5 = No cracking4 = Slight cracking (visible with magnifying glas
20、s only)3 = Some cracking (just visible with eye)2 = Moderate cracking1 = Severe cracking0 = Film chips off completely8.3 Add the ratings of the sealed and unsealed portionstogether to obtain a total rating from 0 to 10 for the appliedpaint.8.4 Record humidity during the drying period.NOTE 5Changes i
21、n visual gloss may also indicate poor film forma-tion.9. Keywords9.1 coalescence; cracking; film formation; latex paint; lowtemperatureASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this stand
22、ard 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 is subject to revision at any time by the responsible technical committee and must be reviewed every five years andi
23、f 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 Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, wh
24、ich 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
25、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:/ 07 (2017)2
