ASTM_D_3003_-_01_2012.pdf

Designation:D300301(Reapproved 2012)Standard Test Method forPressure Mottling and Blocking Resistance of OrganicCoatings on Metal Substrates1This standard is issued under the fixed designation D3003;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 determination of the pressuremottling and sticking,or blocking resistance of organic coat-ings applied to coil-coated or factory-coated metal prior tofabrication.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 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.Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 blocking or sticking,nthe condition wherein coatedsurfaces adhere to each other.2.1.2 pressure mottling,nfilm distortion or uneven patterngiving a change of gloss and nonuniform appearance.It isusually caused by pressures within a painted coil or stackedpainted sheets or other painted products.3.Summary of Test Method3.1 The coated metal is cut into suitably sized panels.Astack of these panels is then subjected to a specified pressureand temperature for a specified time to permit any pressuremottling and sticking or blocking to develop.The applied heatof the test apparatus is turned off and,after cooling,thespecimens are examined for any signs of sticking(or blocking),and mottling.The results are rated on the 0 to 10 scale and maybe used in accepting or rejecting the coating in accordance withstandards established between the purchaser and the seller.4.Apparatus24.1 Suitable Hydraulic or Mechanical Press or Vise may beused.The equipment shall be capable of producing the requiredtest pressure in kilopascals(or pounds-force per square inch)and be equipped with a suitable device for measuring the forceapplied.5.Test Specimens and Conditions5.1 At least four,and preferably six,flat panels shall be cutfrom the coated stock,the age of which shall be within thelimits agreed upon between the purchaser and the seller.5.2 Panels should be at least 100 by 70 mm(4 by 2.5 in.)toprovide an adequate area for assessing the results.Where theequipment does not provide adequate pressure,smaller panelsmay be used.The minimum recommended size is 50 by 50 mm(2 by 2 in.).5.3 Use only flat panels.If necessary,file the edges smoothto ensure maximum contact between the surfaces.When theequipment permits,panels larger than the pressure plates maybe used,thus eliminating any effect from uneven edges.Withthis method,the kilopascals(or pounds of force per squareinch)is calculated using only the panel area within the pressureplates.5.4 The film thickness of the coating under test shall be asspecified or agreed upon between the purchaser and the seller.5.5 The coated stock shall be tested under the conditions ofpressure,temperature,and time mutually agreed upon betweenthe purchaser and the seller.Pressures ranging from 750 to2400 kPa(110 to 350 psi),temperatures from 43 to 60C(110to 140F),and times of 2 to 16 h have been used.5.6 In the absence of agreed or specified test conditions,apressure of 750 6 35 kPa(110 6 5 psi),a temperature of 436 1.5C(110 6 3F),and a time of 16 h shall be used.5.7 The total force applied is measured by a suitable gageand the pounds of force per kilopascals(or square inch)is1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.53 on Coil Coated Metal.Current edition approved June 1,2012.Published August 2012.Originallyapproved in 1971.Last previous edition approved in 2006 as D3003 01(2006).DOI:10.1520/D3003-01R126.2Suitable equipment includes presses and drill press vises modified for use witha torque wrench if agreed upon between purchaser and seller(Hensley,W.L.,“Pressure Mottling Test,”Journal of Paint Technology,Vol 40,No.517,February1968,p.54A).Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 calculated by dividing the force by the area in square inches ofone side of one panel.6.Procedure6.1 Stack the panels face to back as used in production withboth face and back coatings applied.Limit the number ofpanels in the test to the quantity that can be heated rapidly toand maintained at the correct panel temperature throughout thetest.6.2 For presses having heating units,place the test panels inthe press and bring the heating platens in contact but with lightpressure.Turn on the heating unit