ASTM_F_2496_-_05_2011e1.pdf

Designation:F249605(Reapproved 2011)1Standard Practice forDetermining the Scratch Hardness and Scrape Adhesion ofPrints and Coatings1This standard is issued under the fixed designation F2496;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.1NOTERevised the units presentation and added a units statement editorially in October 2011.1.Scope1.1 This practice describes procedures to obtain subjective,but comparative data for scratch hardness and scrape adhesionof coatings and color images produced by printers,copies andother reprographic devices.1.2 This method simulates conditions where the surface ofvarious substrates such as paper,film,cloth,and so forth maybe subject to failure under mechanical force.1.3 This test method covers the determination of the scratchhardness and scrape adhesion of coatings.Results are ex-pressed in terms of force-to scratch coatings on substrates usedin printing.1.4 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.1.5 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:2.1.1 scratch hardnessthe force necessary to cut throughthe coating to the substrate.2.1.2 scrape adhesionscratch resistancethe force re-quired to scrape a path through the coating or print,when thestylus begins its motion.By moving a free edge of the testcoating against a round stylus or loop under a variable loadexpressed in grams,scrape resistance is determined as theminimum load in grams required to cut through the film to thesubstrate.3.Summary of Practice3.1 The scratch hardness and scrape adhesion is determinedby pushing the substrate with coating beneath a rounded stylusor loop that is loaded in increasing amounts(weights)until thecoating is scratched.4.Significance and Use4.1 The image life of printed media displayed in bothtypical office and outdoor environments is dependent oncoating scratch resistance.While natural aging is the mostreliable method of assessing coating scratch resistance,thelength of the time required makes this method impractical formost materials.4.2 Factors in the office and outdoor environments,such asheat,cold,thermal shock,ultraviolet/visible radiation andwater vapor can have similar effect on the scratch resistance ofcoatings and prints as mechanical force.4.3 Good scratch resistance is a prime consideration forcoated media and prints.Highly absorptive coatings in digitalprinting have a tendency to dusting,flaking and cracking whenfolded.4.4 This practice utilizing mechanical force allows com-parative studies of coated and printed media.It is most usefulin providing relative ratings for media which exhibit significantdifferences in performance.5.Interferences5.1 Since the scratch resistance adhesion is dependent ontemperature and humidity,it is important that the effects ofmechanical force be assessed under the conditions appropriateto the end use applications.While printed media may behandled and displayed under a variety of conditions,this testpractice is intended to measure scratch resistance in typicalindoor environments.5.2 The adhesion is dependent on temperature and should betested at the manufacturers recommended temperature for thebest performance.5.3 The scratch resistance of color images is dependent onthe printing mode,the type of color and the amount of appliedink.1This practice is under the jurisdiction of ASTM Committee F05 on BusinessImaging Products and is the direct responsibility of Subcommittee F05.07 on Ink JetImaging Products.Current edition approved Oct.1,2011.Published March 2012.Originallyapproved in 2005.Last previous edition approved in 2005 as F249605.DOI:10.1520/F2496-05R11e1.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.4 The practice is intended to measure scratch resistance ofprinted media without specifying above-mentioned parameters.6.Apparatus6.1 Balanced Beam Scrape Adhesion and Mar Tester(Cata-log Number SG-8101)for example available from BykGard-ner2(Fig.1)consisting of a balanced beam to which is secureda platform for supporting weights,and a rod at an angle of 45that holds the scraping loop or the stylus.The rod shall be setso that the scraping loop or the rounded stylus contacts testsurfaces directly below the weights.On the other end of thebeam is a counter-weight.A cam is rotated to lower and raisethe stylus and a sample bed mou