ASTM_D_5166_-_97_2008e1.pdf

Designation:D516697(Reapproved 2008)1Standard Practice forLaboratory Preparation of Gelled Vehicle Samples Using aMicrowave Oven1This standard is issued under the fixed designation D5166;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.1NOTEAn editorial correction was made in 8.1 in March 2009.1.Scope1.1 This practice outlines a procedure for preparing gelledvehicle samples using a microwave oven.1.2 The test samples can be used for characterizing thegelability or reactivity of resins,gelling agents,and vehiclesused in the manufacture of oil based printing inks,or both.1.3 Evaluation of the gelled vehicles may,depending uponpreference,be either visual or instrumental.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D154 Guide for Testing VarnishesD1545 Test Method for Viscosity of Transparent Liquids byBubble Time MethodD1725 Practice for Preparing Resin Solutions for ViscosityMeasurement by Bubble Time MethodD4040 Test Method for Rheological Properties of PastePrinting and Vehicles by the Falling-Rod ViscometerE1 Specification for ASTM Liquid-in-Glass Thermometers3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 gel,nAny resin solution,or more complex blend ofresins and alkyds that has been cooked or reacted with a gellingor cross-linking agent to build molecular weight and thatexhibits a pseudoplastic rheology.(Also called“gelled ve-hicle.”)3.1.2 gelling agent,nin the context of ink resins andvehicles,gelling agents or gellants are typically organo-aluminum compounds that react with carboxylic acid andhydroxyl groups present on the backbone of resins and alkydsto form cross-linked networks.(Also called“gellant.”)3.1.3 gel length,nReferences to long,medium,and shortgel length refer to the length of a string of gelled vehicleobserved when pulling apart a small sample of vehicle with aspatula(that is,a long gel is very fluid and forms a“long”filament;a short gel has little flow and forms a“short”filament).3.1.4 pregel,nThe resin solution or vehicle componentscomprising the vehicle prior to the addition of gelling agentand viscosity adjusting solvent.(Also called“pregel vehicle.”)4.Summary of Practice4.1 Prepare a pregel resin solution or vehicle.4.2 Separate the pregel vehicle into five or more aliquots towhich various levels of gellant are added.Alternately,variousgellants can be added at a given concentration to compare theireffectiveness.4.3 Place the test samples on a turntable in the microwaveoven and heat the samples at full power until the desired testtemperature is attained.4.4 After the prescribed waiting period,test and ratesamples for gelability.5.Significance and Use5.1 This practice provides a means of preparing a number ofgel vehicle samples with minimum use of materials and time.It provides a means of quickly characterizing and comparingthe gelability or reactivity of resins,vehicles,and gellingagents.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.37 on Ink Vehicles.Current edition approved June 1,2008.Published June 2008.Originallyapproved in 1991.Last previous edition approved in 2003 as D5166 97(2003).DOI:10.1520/D5166-97R08E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.Apparatus6.1 Mercury Thermometer,capable of reading from 0 to250C and conforming to Specification E1.6.2 Jars,(40 mm in diameter by 83 mm in height),70 cm3with nonmetallic screw-on lids.6.3 Microwave Oven,common 750-watt.36.4 Microwave Oven Carousel,if not contained in themicrowave oven.6.5 Glass Dish,15.2 cm in diameter.6.6 Balance or Scale,capable of weighing to 60.1 gaccuracy.6.7 Ink Knife or Rigid Spatula.6.8 Rheology Testing Apparatus,at the discretion of theuser.7.Reagents and Materials7.1 Nonvolatile materials including resins,alkyds,gellants,etc.,consistent with those used in the manufacture of litho-graphic ink vehicles,for example,aromatic hydrocarbonresins,modified rosin ester resins,long oil linseed isophthalicalkyds,and aluminum compounds.7.2 S