1、Designation: D4217 07 (Reapproved 2013)Standard Test Method forGel Time of Thermosetting Coating Powder1This standard is issued under the fixed designation D4217; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method determines the length of time athermosetting coating powder takes to gel on a polished metalsurface at a spe
3、cified temperature, such as 204C (400F). Thedetermination of the gel time is a very simple method for thecharacterization and quality control of coating powders.However, the gel time determined by this method is notdirectly related to the time for the coating powder to cure inpractical applications.
4、1.2 This standard does not purport to address all of thesafety concerns, 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 prior to use.2. Referenced D
5、ocuments2.1 ISO Standards:ISO 81306:1992 Coating powdersPart 6: Determinationof gel time of thermosetting coating powders at a giventemperature23. Terminology3.1 Definitions:3.1.1 coating powder, nfinely divided particles of resin,either thermoplastic or thermosetting, generally incorporatingpigment
6、s, fillers, and additives and remaining finely dividedduring storage under suitable conditions, which, after fusingand possibly curing, give a continuous film.3.1.2 cure time of a coating powderthe time required fora thermosetting coating powder to sufficiently chemicallycrosslink at a given tempera
7、ture to provide the required coatingproperties.3.1.3 gel time of a coating powderthe interval required ata given temperature for a coating powder to be transformedfrom a dry solid to a gel-like state.3.1.4 powder coating, ncoatings which are protective ordecorative, or both, formed by the applicatio
8、n of a coatingpowder to a substrate and fused in a continuous film by theapplication of heat or radiant energy.3.1.5 thermosetting, adjdescribing a material that, whenheated per a minimum recommended cure condition, under-goes a chemical reaction and a permanent change to a moredurable state capable
9、 of specific properties as designed forsubstrate protection or decoration, or both.4. Significance and Use4.1 This test method is useful for selecting coating powdersthat gel in the desired time at the specified temperature. Themethod is not useful for determination of cure time.5. Apparatus5.1 Hot
10、Plate,3having an electrically heated metal blockwith a polished surface capable of being maintained at tem-peratures between range 130 to 230C (266 to 466F) to within62C (64F). The temperature should be controlled by meansof a thermoregulator.NOTE 1There are expected differences in results between t
11、his methodand ISO 81306 which requires a heating block with small depressions.5.2 Stopwatch or Timer, accurate to at least 1 s.5.3 Stirrer, of very low heat capacity and of suitable size.Wooden stirrers with dimensions of 2 mm by 6 mm by 130 mmor (116 in. by14 in. by 5 in.) have been found suitable.
12、5.4 Surface Contact Thermocouple, suitable for use at 150to 250C (300 to 480F) and reading no greater than 1C (2F).5.5 Measuring Spoon, of 1.25 cc (14 tsp) capacity.5.6 Scraper, made of material softer than that of the heatingblock, for removing the test material from the heating blockwithout scratc
13、hing its surface.6. Selection of Specimens6.1 Obtain a representative sample of the coating powder.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.51 on Powder Coatings.Cur
14、rent edition approved June 1, 2013. Published July 2013. Originally approvedin 1982. Last previous edition approved in 2007 as D4217 07. DOI: 10.1520/D4217-07R13.2Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.3The sole s
15、ource of supply of the Model SS-200 hot plate known to thecommittee at this time is Thermo-Electric Co., 455 Route 30, Imperial, PA 15126.If you are aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at
16、ameeting of the responsible technical committee,1which you may attend.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 Store the sample of coating powder in accordanc
17、e withthe manufacturers recommendations, after sampling and priorto testing.6.3 A specimen shall consist of approximately 1.25 ml (14tsp) of coating powder.7. Procedure7.1 Place the hot plate in a draft-free location or use athree-sided draft shield constructed to eliminate drafts.7.2 Allow a minimu
18、m of 30 min for the hot plate to stabilizeafter reaching the temperature at which calibration is to bemade.7.3 Verify the hot plate temperature with the surface contactthermocouple to 62C (64F). The temperature of the hotplate will likely vary slightly over the hot plate surface. Thusthe verificatio
19、n is only valid for the immediate location tested.Gel times should only be measured at the location that wasverified.7.4 Carry out the gel time determination in duplicate.7.5 Using the measuring spoon, transfer 1.25 ml (14 tsp) ofthe material under test onto the verified area of the hot plate.7.6 As
20、 soon as the powder hits the plate, start the stop watchand begin stirring.7.7 Stir the molten material in small circular movementswith the stirrer. When thickening starts, maintain the overallstirring action, and periodically lift the stirrer approximately 25to 50 mm (1 to 2 in.) above the molten m
21、aterial to produce afilament of molten material. When filaments break and can nolonger be drawn from the then gelled material, stop the timerand record the time to the nearest second. This is the gel time.7.8 Clean the gelled material from the surface of the hotplate with the scraper. If the plate s
22、urface becomes pitted orscratched, polish it smooth or replace it.7.9 Repeat the determination with a fresh sample. If the tworesults differ by less than 5 % of the lower value, calculate andreport the arithmetic mean. If the difference between the tworesults exceeds 5 %, carry out a third determina
23、tion andcalculate and report the arithmetic mean of all three results tothe nearest second. If the difference between the result of thethird determination and those of the other two determinationsis also greater than 5 %, state this and the individual results inthe test report.8. Report8.1 Report th
24、e following information:8.1.1 All details necessary to identify the product tested,8.1.2 A reference to this standard,8.1.3 The test temperature,8.1.4 The amount of powder used if other than the defaultamount,8.1.5 The result of the test as indicated in section 7.9,8.1.6 Any deviation from the test
25、method specified, and8.1.7 The date of the test.9. Precision and Bias9.1 PrecisionIt is not possible to specify the precision ofthe procedure in Test Method D4217 for measuring gel timebecause adequate data has not been established. No activity isplanned to develop such data.9.2 BiasThis test method
26、 has no bias because the value forgel time is defined solely in terms of this test method.10. Keywords10.1 coating powder; gel time of coating powder; hot plate;powder coating; thermosettingSUMMARY OF CHANGESCommittee D01 has identified the location of selected changes to this standard since the las
27、t issue (D4217 - 02)that may impact the use of this standard. (Approved June 1, 2007.)(1) Section 7 and 8 combined for clarity.ASTM 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
28、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 andif not re
29、vised, 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, which you
30、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,United S
31、tates. 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/).D4217 07 (2013)2
