ASTM_D_4576_-_16_2021.pdf

Designation:D457616(Reapproved 2021)Standard Test Method forMold Growth Resistance of Wet Blue and Wet White1This standard is issued under the fixed designation D4576;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 moldgrowth resistance of Wet Blue and Wet White subject to storageand shipping requirements and intended for use in leathermanufacturing.This test method may not be suitable toevaluate fungicides that are inactivated by proteins.Thisincludes alkyldimethylbenzyl ammonium chlorides.1.2 Conclusions about mold growth resistance are drawnfrom the results by comparing the test with a simultaneouslyrun control of known resistance.Success or failure is deter-mined by the amount of mold growth relative to the control.1.3 To allow use of this test method by any laboratory,flexibility has been permitted in times,temperature,andhumidity of incubation,inoculum,hide sampling area,andchoice of control.These may be adjusted to fit local conditionsbut must be standardized.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 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 Wet Bluehide or skin,or split of a hide or skin,tanned with basic chromium sulfate,containing approximately50%moisture and having an acidic pH.2.1.2 Wet Whitea hide or skin,or split of a hide or skintanned with organic or non-organic tanning agents(excludingchromium or iron containing agents and vegetable extracts),containing approximately 50%moisture.3.Summary of Test Method3.1 Wet Blue and Wet White test specimens are surroundedby but not covered with agar,inoculated,and incubated.3.2 After various incubation periods,mold growth is ratedas a percentage of the Wet Blue and Wet White surface coveredby mold.3.3 Resistance to mold growth of the Wet Blue or Wet Whitetest specimen is determined by comparison with Wet Blue orWet White of known resistance characteristics(the control),that is tested simultaneously.4.Significance and Use4.1 This test method provides a technique for evaluatingmold growth resistance characteristics of Wet Blue and WetWhite,and should assist in the prediction of storage timebefore molding occurs.4.2 The degree of correlation between this test and commer-cial quantities of Wet Blue and Wet White in storage orshipment situations,or both,has not been fully determined.5.Interferences5.1 A common interference is contamination of plates,agar,or samples by unwanted organisms that settle in from theenvironment.5.2 Volatility and Leachability of BiocidesA“zone ofinhibition”where no mold grows on the agar adjacent to thespecimen indicates that the fungicide may leach.6.Apparatus6.1 Petri Dishes,120 mm diameter.Sterile plastic dispos-able dishes are preferred.6.2 Incubator,or location providing similar conditions be-ing free of drafts,and capable of a constant(62 C)tempera-ture within the 26 to 30 C range.6.3 Medicine droppers,disposable plastic type delivering 30to 35 drops per mL.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved Sept.1,2021.Published October 2021.Originallyapproved in 1986.Last previous edition approved in 2016 as D4576-16.DOI:10.1520/D4576-16R21.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.17.Reagents and Materials7.1 Potato Dextrose Agar,2a dehydrated plating mediumused in culturing yeasts and molds from dairy products.7.2 Inoculum,3Aspergillus niger 1 106spores per mL,orother organism or a combination of organisms known to beindigenous to the storage area of the Wet Blue and Wet White.8.Sampling,Test Specimen,and Test Units8.1 Take test