1、Designation: D279 02 (Reapproved 2012)Standard Test Methods forBleeding of Pigments1This standard is issued under the fixed designation D279; 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 pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These test methods cover procedures for determiningthe bleeding ch
3、aracteristics of dry pigments by direct solventextraction of the pigment and by overstriping a film with awhite coating and observing for the color migration from thebase coat containing the pigment.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses
4、are for informationonly.1.3 This standard does not purport to address all of thesafety problems, 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 limitations prio
5、r to use.2. Referenced Documents2.1 ASTM Standards:2D2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD2616 Test Method for Evaluation of Visual Color Differ-ence With a Gray Scale3. Summary of Test Methods3.1 Test Method AThe pigmen
6、t is shaken with toluene,filtered, and the filtrate observed for color.3.2 Test Method BA coating using the pigment under testis prepared and applied to one half of a panel. A white finish isapplied over the dried colored coating and extended to theuncoated portion of the panel. The dried overstripe
7、 coating isexamined for color migration from the base coat.4. Significance and Use4.1 Test MethodAdetermines the amount of color producedwhen the pigment is in direct contact with a selected solventsuch as toluene. It is useful as a rapid, easily conducted test ofthe general bleeding characteristics
8、 of pigments.4.2 Test Method B determines the amount of color migra-tion into a white film applied over a base coat containing thepigment. It may give a more practical evaluation of whether apigment will meet specific requirements for bleed resistance.4.3 Both Test Method A and Test Method B measure
9、 theextent of bleed.TEST METHOD A, DIRECT SOLVENT CONTACTWITH PIGMENT5. Procedure5.1 Place 0.50 g of pigment (Note 1) in a test tube or vialand add 20-mL of reagent grade toluene (Note 2). Close witha stopper, shake well for 10 s, and let stand 15 min. Repeat the10-s shake and let stand 45 min.NOTE
10、1Additional amounts of pigment may be used by prioragreement for denser inorganic pigments. A maximum of 1.5 g isrecommended for even the dense lead chromate pigments.NOTE 2Other solvents may be used, by mutual agreement between theparties involved, in place of toluene in a specific pigment bleed ev
11、aluation.5.2 Filter through a glass funnel using double filter paperthat has first been wet with toluene and collect approximately10 mL of filtrate in a 23 mm outer diameter flat bottom vial. Ifthe filtrate is cloudy, refilter to get a clear filtrate.NOTE 3In the case of colloidal particles, it may
12、be necessary tocentrifuge the filtrate.5.3 Hold the vial containing the filtrate above a whitebackground and look down through the filtrate for colorationcaused by pigment bleed. Describe the degree or severity ofbleed according to the following terminology or use the GrayScale (Test Method D2616):5
13、.3.1 NoneNo perceptible color (that is, no bleed).5.3.2 SlightA faint but distinct coloration.5.3.3 ModerateA pronounced but not severe coloration.5.3.4 SevereAn intense coloration.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Appli
14、cations and are the directresponsibility of Subcommittee D01.31 on Pigment Specifications.Current edition approved Nov. 1, 2012. Published November 2012. Originallyapproved in 1928. Last previous edition approved in 2007 as D279 02 (2007).DOI: 10.1520/D0279-02R12.2For referenced ASTM standards, visi
15、t 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 19428-295
16、9. United States1TEST METHOD B, WHITE OVERSTRIPE OF APIGMENTED FILM6. Procedure6.1 Prepare a coating of agreed upon composition, using thepigment under test, and prepare a film of this coating by anymethod that will give a smooth and uniform film of normalcoating thickness (that is, in the range fro
17、m 1 to 3 mils) (25 to75 m) leaving a portion of the substrate uncoated. Cure thefilm under conditions appropriate to the end use. For air dryfilms, dry at room temperature, approximately 25C (77F) fora minimum of 24 h.6.2 Pretreatments of the colored coating, such as sanding orsolvent wipe, or both,
18、 may be used before the overstripe, asagreed upon by the purchaser and seller.6.3 Overstripe with a white finish of agreed upon composi-tion. Ensure that the overstripe film is of uniform thickness andapplied at complete hiding; otherwise, color show-through maybe erroneously interpreted as bleed.6.
19、4 Extend the overstripe film to the uncoated portion of thepanel. Dry the overstripe under conditions mutually agreedupon by the involved parties.6.5 Examine for color migration from the base coat into thewhite topcoat within 2 h after drying. Evaluate, as agreed uponby the purchaser and seller, the
20、 extent of bleed in accordancewith the visual scale in Test Method A (5.3) or measure theactual color difference versus the uncoated portion using DeltaE color measurements, Practice D2244.7. Precision and Bias7.1 The precision and bias are considered to be undetermin-able as they will vary with the
21、 solvent or solvent blends usedin Test Method A and with the type of base coat and type ofoverstriping used in Test Method B.8. Keywords8.1 bleeding pigments; migration; overstripe; pigmentbleeding testASTM International takes no position respecting the validity of any patent rights asserted in conn
22、ection 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 is subject to revision at any time by the respons
23、ible 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 Headquarters. Your comments will receive careful c
24、onsideration 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 standard is copyrighted by ASTM International, 10
25、0 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 ASTM website (www.astm.org/COPYRIGHT/).D279 02 (2012)2
