ASTM_D_4640_-_86_2022.pdf

Designation:D464086(Reapproved 2022)Standard Test Method forDetermining Stroke Cure Time of Thermosetting Phenol-Formaldehyde Resins1This standard is issued under the fixed designation D4640;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 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 the determination of the curerate at any specified temperature for a thermosetting phenol-formaldehyde resin.The time at that temperature required tomake a fluid mixture change into a hard immovable massindicates speed of cure.1.2 The values stated in inch-pound 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.1.3 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 stroke cure time,nthe time required for a resin beingheld at a specified temperature on a hot plate and being strokedwith a spatula,to adhere to the hot plate and not to the spatula.3.Summary of Test Method3.1 This test method employs the use of controlled heat anda thin layer of resin to determine the time in seconds requiredto change from a fluid stage to a cured immovable stage.4.Significance and Use4.1 This method is significant as a process control forpolymerization time.4.2 When the cure times are determined at several tempera-tures and plotted as time versus temperature,different resinscan be compared for curing characteristics.5.Apparatus5.1 Electric Hot Cure Plate,with a smooth surface free ofrough spots with adjustable control to hold the temperaturewithin 3.5 F(2 C)(Note 1).5.2 Spatula,3 by716in.(75 by 10 mm),stainless.5.3 Stopwatch.5.4 Knife,brass,putty with straight edge.6.Procedure6.1 Adjust the hot plate to the desired test temperature.NOTE1Usual temperatures are 300 F(150 C),320 F(160 C),and330 F(165 C).6.2 Place an approximately 0.5-g specimen on the hot plateand spread over an approximately 2-in.2(130-mm2)area witha clean spatula as quickly as possible.Start the stopwatchimmediately upon adding the specimen to the hot plate,thenstroke steadily across the specimen in alternating smoothingand patting motions.6.3 As the resin approaches the cured stage,it becomesmore viscous and stringy.Stop the stopwatch when the resin onthe hot plate and the spatula no longer adhere to each other.Record the elapsed time.6.4 Remove cured resin from hot plate immediately with thestraight edged putty knife.NOTE2The longer on the hot plate,the harder it is to remove.NOTE3Test results can be affected by differences in construction ofhot plates,the stroking and patting with spatula,and the starting andstopping of the stopwatch.7.Report7.1 Report the following information:7.1.1 Stroke cure time in seconds;record to the nearestwhole number.7.1.2 Test temperature.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.33 on Polymers and Resins.Current edition approved June 1,2022.Published July 2022.Originally approvedin 1986.Last previous edition approved in 2017 as D4640 86(2017).DOI:10.1520/D4640-86R22.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.18.Precision and Bias8.1 No statement is made about either the precision or biasof this method for measuring stroke cure since the resultmerely states whether there is conformance to the criteria forsuccess specified in the procedure.9.Keywords9.1 phenol-formaldehyde resins;stroke cure timeASTM 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 infringement of such