ASTM_D_3926_-_05_2011.pdf

Designation:D392605(Reapproved 2011)Standard Test Methods forPercent Solids in Titanium Dioxide Slurries1This standard is issued under the fixed designation D3926;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 These test methods cover the determination of theweight percent of solids in aqueous slurries of titanium dioxidepigments by either the use of a gravity-convection oven(Method A),infrared radiation moisture analyzer(Method B),or a microwave drying system(Method C).1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This test 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:2D1193 Specification for Reagent Water3.Summary of Test Method3.1 Oven Method:3.1.1 Slurry is weighed by difference into a tared aluminumfoil dish,dried at 105C in an oven for 1 h,cooled in adesiccator,and weighed.3.2 Infrared Method:3.2.1 Slurry is dried under infrared lamps for a specifiedtime and temperature.The results are obtained directly formthe units display panel.3.3 Microwave Method:3.3.1 2 to 4 g of slurry is placed between two glass fiberpads and dried in a microwave drying system.The results areobtained directly form the units display panel.4.Significance and Use4.1 These test methods are intended as a quick and reliableprocedure for measuring the titanium dioxide pigment contentof aqueous slurries.Included with the pigment content in thepercent solids are the various nonvolatile additives used inpreparing a stable slurry.Because the aluminum and silicaoxide treatments on the more highly treated titanium dioxidepigments may change somewhat with prolonged drying,in theoven method the solids of the slurry are considered dry afterheating at 105C for 60 to 65 min.The high temperatureassociated with the infrared moisture analyzer may also effecta change in the aluminum and silica oxide treatment on highlytreated TiO2products.Therefore,care in selection of time andtemperature are critical to obtain accurate results with theinfrared method.With the short duration of test associated withthe microwave drying system,overdrying is not a concern.5.Apparatus5.1 Oven Method:5.1.1 OvenLaboratory oven capable of maintaining atemperature of 105 6 2C(Note 1).The oven may be agravity-convection type or an oven with a low velocity,forceddraft.An oven with a high-velocity,forced-draft air change,commonly used for baking finishes,is not suitable.NOTE1The temperature in the oven must be constantly monitored.Many older ovens will no longer maintain 62C;some will maintain thistolerance for a while but occasionally the thermostat will“stick”and thetemperature will vary considerably.5.1.2 BalanceLaboratory analytical balance,accurate to0.1 mg,with 1-g optical readout range for fast weighing.NOTE2Periodically check the accuracy of the 1-g optical scale of thebalance by use of a known 1-g weight;adjust the balance if needed.Thezero adjustment of the optical scale needs to be checked at least every hourroutinely and immediately if there is any possibility of a spill havingoccurred on the balance.5.1.3 DesiccatorStandard laboratory desiccator utilizingan indicating drying medium.5.2 Infrared Method:5.2.1 Infrared Moisture AnalyzerAutomated moistureanalyzer combining infrared drying technology and a precisionanalytical balance in a single unit.5.3 Microwave Method:1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.31 on Pigment Specifications.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1980.last previous edition approved in 2005 as D3926 05.DOI:10.1520/D3926-05R11.2For 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 5.3.1 Microwave Drying SystemA National RecognizedTesting Laboratory(NRTL)approved 630 W microwave dry-ing system with 50 g,0.1 mg readability internal balance tomeasure moisture/solids from 0.1 to 99.99%.6.Reagents and Materials6.1 Oven Method:6.1.1 Purity of WaterUnless otherwise indicated,refer-ences to water shall be understood to mean reagent waterconforming to Type II of Specification D1193.6.1.2 Aluminu