1、Designation: D7306 07 (Reapproved 2013)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.2. Referenced Documents2.1 ASTM Standards:2D823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Relat
5、ed 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 termperatures, typically4 6 2C (39 6 4F).4
6、. 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 the cold cabinetand eva
7、luated 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 at lowtemperatures. Th
8、is 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 information, ratherra
9、nking 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 Paint Applicator(s), typic
10、ally 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.6.5 Instrument, to record relative humidity (typically 20 to100 %).NOTE 2Variation in humidity can have impact on film
11、formation.6.6 4X 12X Magnifying Glass,6.7 Test Paint.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved June 1, 2013. Publis
12、hed June 2013. Originallyapproved in 2007. Last previous edition approved in 2007 as D7306 07. DOI:10.1520/D7306-07R13.2For 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
13、to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Paint test charts selected for use should be from a sole supply across theexperiment to ensure accurate comparisons between test samples.Copyright ASTM Inter
14、national, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. 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 test chart with sealed and un-sealed areason a v
15、acuum 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 8.2.NOTE 3This practice can be conducted at se
16、veral 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 film for continuity under a magnify-ing glass
17、. 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 glass only)3 = Some cracking (just visible with ey
18、e)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 in visual gloss may also indicate poor film for
19、ma-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 standard are expressly advised that determination o
20、f 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 andif not revised, either reapproved or withdrawn.
21、 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, which you may attend. If you feel that your comm
22、ents 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,United States. Individual reprints (single or
23、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 ASTM website (www.astm.org/COPYRIGHT/).D7306 07 (2013)2
