1、Designation: D7233 08 (Reapproved 2012)Standard Test Method forTesting Fracture of Level Paintbrush Filaments1This standard is issued under the fixed designation D7233; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st 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 test method covers a procedure for determining thenumber of fractures present when paintbrush filaments arebent.1.2
3、 This method is applicable only to monofilaments withconsistent longitudinal cross sectional dimensions commonlyreferred to as “level” filaments.1.3 The values derived are in percent fractured filaments.For example, 2 fractured out of 18 filaments tested =218 or11 %.1.4 The values stated in inch-pou
4、nd units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theres
5、ponsibility 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. Summary of Test Method2.1 Filaments are clamped in place and bent to a specificdisplacement. While bent and still in the fixture,
6、they areevaluated for fracture by visually determining whether thefilaments have cracked or been permanently deformed and willnot recover to virtually straight filaments. (See Fig. 1 and Fig.2).3. Significance and Use3.1 This method is intended to evaluate filaments for suit-ability of use in paintb
7、rushes prior to manufacture. Filamentfracture resistance is very important because paintbrushes arebent or flexed during painting and it is necessary that thefilaments are not permanently deformed with usage.4. Apparatus24.1 The apparatus for this method is shown in Fig. 3.Filaments are secured betw
8、een two clamps. The handwheel onthe front of the gauge is rotated to bring the ends of thefilaments toward each other as measured by the dial indicatorat the top of the gauge.4.2 The device is very delicate and care should be used in itsoperation. To prevent instrument damage, the clamps must notbe
9、brought together closer than a reading of 0.750 in. (19.0mm) on the dial indicator.5. Sampling, Test Specimens and Test Units5.1 Record the polymer type, filament size and filamentcross-sectional shape.5.2 The sample filaments shall be conditioned for one (1) hat 73.5 6 3.5F (23.0 6 2.0C) and 50 65
10、% relative humidity.5.3 The sample filaments shall be cut to a minimum of 1.5in. (38.1 mm).5.4 The distance between clamps on the test unit shall be 1.0in. (25.4 mm) at a reading of 0.0 (zero deflection). (See Fig. 4.)6. Procedure6.1 Select three distinct sections of the bundle, box or lot offilamen
11、ts to be evaluated. Do not include filaments from theperimeter of a bundle. Pull six (6) filaments from each sectionat equally dispersed intervals.6.2 Set the clamps in a parallel horizontal position with thedial indicator set at 0.0 (zero deflection). (See Fig. 4.)6.3 Place the six (6) filaments in
12、 the clamps. Be sure that nofilament overlaps or is on top of another filament. Close clampsto secure.6.4 Rotate the handwheel counterclockwise to deflect thefilaments until the dial indicator reads 0.650 in. (16.5 mm)travel distance (see Fig. 5).1This test method is under the jurisdiction of ASTM C
13、ommittee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.61 on Paint Application Tools.Current edition approved Nov. 1, 2012. Published November 2012. Originallyapproved in 2008. Last previous edition approved in 2008 as D7233 08. DOI
14、:10.1520/D7233-08R12.2The sole source of supply of the assembled fracture gauge test device known tothe committee at this time is T. S. Simms and Co., 33 Bridge Rd., St. John, NewBrunswick, Canada. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headqu
15、arters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.5 Immediately inspect each filament for fracture. Frac-
16、tured filaments will exhibit a sharp point of fracture, will bekinked and will not be straight (see Fig. 1). Filaments withoutfracture will recover to be straight or will exhibit a deformationat the radius of bend (see Fig. 2).6.6 Repeat steps 6.2-6.5 for remaining two (2) sets of six (6)filaments.6
17、.7 Report the results as fractured filaments per number offilaments tested. For example, 2 fractured out of 18 filamentstested =218 or 11 %.7. Calculation or Interpretation of Results7.1 Calculate the percent (%) fractured filaments and com-pare results to product specifications. For example, (218)
18、100=11%.7.2 The results can be influenced by cross sectional shape,cross sectional projected area, polymer type, processing historyof the polymer and the processing history of the filamentsselected.7.3 Results can be affected by choice of testing conditions,that is, cold, dry conditions or hot, wet
19、conditions. Interlabo-ratory comparisons should be done at identical conditions.FIG. 1 Failed FilamentFIG. 2 Not Failed FilamentFIG. 3 Fracture GaugeFIG. 4 Dial Face Set to 0.0FIG. 5 Dial Face Reading 0.650 in.D7233 08 (2012)28. Precision and Bias8.1 Precision:8.1.1 Interlaboratory testing was done
20、by three labs, eachtesting filaments removed from the same sample bundles inround-robin testing. Three different filament types known tohave different fracture resistance were tested.8.1.2 RepeatabilityThe standard deviation among labswas not greater than 3.2 % failed filaments per bundle whenthree
21、separate samples were tested from the same bundle byeach lab on each of the three separate filament types.8.1.3 ReproducibilityIndividual filaments cannot be testedtwice due to the destructive nature of the test.8.2 BiasBias cannot be determined since there is nostandard filament reference establish
22、ed.9. Keywords9.1 bendingASTM 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 of the validity of any such patent rights, and the riskof infring
23、ement 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. Your comments are invited either for revision of this standard
24、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 comments have not received a fair hearing you shouldmake your views
25、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 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/).D7233 08 (2012)3
