1、Designation: D 7306 07Standard Practice forTesting Low Temperature Film-Formation of Latex Paints byVisual Observation1This standard is issued under the fixed designation D 7306; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 form a uniform
3、 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 theresponsibil
4、ity 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:2D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on
5、 Test PanelsD 3793 Test Method for Low-Temperature Coalescence ofLatex Paint Films by Porosity Measurement3. Terminology3.1 Definition: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. Summary of Practice4.1 The pa
6、int, 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 evaluated for any cracking of the
7、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. This practice can be used as an a
8、id for determin-ing coalescing solvent level required to form a good film. TestMethod D 3793 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, ratherranking only of the selected ser
9、ies 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.36.3 Paint Applicator(s), typically to apply 3 and 10 mil wet
10、film 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 formation.6.6 4X 12X Magnifyin
11、g 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 test chart with sealed and un-sealed areason a vacuum drawdown plate.7.3 After mixing the paint sample, draw down the p
12、aintuniformly using a straight bar applicator as in Practices D 823.7.4 Immediately place the panel into the cold cabinet.7.5 After 18 h, remove the panel for evaluation as outlinedin 8.2.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Appl
13、ications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved Jan. 1, 2007. Published January 2007.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMSta
14、ndards volume information, refer to the standards Document Summary page onthe ASTM website.3Paint test charts selected for use should be from a sole supply across theexperiment to ensure accurate comparisons between test samples.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
15、 Conshohocken, PA 19428-2959, United States.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 affec
16、t results.8. Report8.1 Examine the dried 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 = Sligh
17、t cracking (visible with magnifying glass 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
18、during the drying period.NOTE 5Changes in 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 mentio
19、nedin 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 is subject to revision at any time by the responsible technical committee an
20、d 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 Headquarters. Your comments will receive careful consideration at a meeting o
21、f 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box
22、 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).D7306072
