1、Designation: D3723 051Standard Test Method forPigment Content of Water-Emulsion Paints by Low-Temperature Ashing1This standard is issued under the fixed designation D3723; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEParagraph 6.2 was corrected editorially in March 2010.1. Scope1.1 This test method covers a procedure for the pigmentcontent
3、 determination of water-based paints. It is applicableonly to pigments that do not decompose or lose weight attemperatures below 500C. Such pigments include most metaloxides, silicates, and a majority of anhydrous inorganic salts.1.2 Many water-based paints contain pigments and organiccolorants that
4、 lose water of hydration or decompose at thistemperature. The residual ash should be carefully inspected forchanges in color or texture that could indicate a pigmentalteration and hence lead to erroneous results. Caution shouldtherefore be exercised when applying this test method tosamples containin
5、g unknown pigment compositions.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of
6、 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. Significance and Use3.1 This test method is used by paint producers and con-
7、sumers for product process control and for product acceptance.4. Apparatus4.1 Oven, forced draft, maintained at 105 6 2C.4.2 Furnace, muffle, maintained at 450 6 25C.4.3 Syringe, 5-mL.4.4 Aluminum Foil Dish, 58 mm in diameter by 18 mm highwith a flat bottom. The bottom of the dish should be as nearl
8、yflat as possible so that a uniform film is produced.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical S
9、ociety,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be und
10、erstood to mean reagent water conformingto Type III of Specification D1193.5.3 Ammonium Hydroxide4Add 1 volume of concen-trated NH4OH (sp gr 0.90) to 3 volumes of water.6. Procedure6.1 Mix samples until homogeneous, preferably on a me-chanical shaker. If air bubbles become entrapped in a sample,stir
11、 it by hand.6.2 Draw approximately 1.5 g of the test paint into a 5-mLsyringe and weigh to 1 mg. Add the paint dropwise (about 30drops) into a preweighed, tared aluminum dish that contains 2mL of water (5.2). Swirl the dish during the addition and1This test method is under the jurisdiction of ASTM C
12、ommittee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jan. 1, 2005. Published February 2005. Originallyapproved in 1978. Last previous edition approved
13、in 1999 as D3723 84 (1999).DOI: 10.1520/D3723-05E01.2For 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.3Reagent
14、Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand Nat
15、ional Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4For guidance in the safe handling of ammonium hydroxide consult theManufacturing Chemists Associations Chemical Safety Data Sheet.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
16、2959, United States.continue the swirling until the specimen is completely dis-persed. Reweigh the syringe to 1 mg. Transfer between 0.4 and0.6 g of sample to the dish. If not, adjust the transferred volumeand prepare a new specimen. If the specimen agglomerates orforms a lump that cannot be dispers
17、ed, a drop or two ofammonia (5.3) may facilitate the dispersement. If the lumpingpersists, discard the specimen and prepare a new one. Preparea duplicate specimen in the same manner.6.3 Dry the specimen and dishes in the 105 6 2C oven fora minimum of 1 h after making certain that the dishes are leve
18、l.If the coating does not uniformly cover the bottom of a dish,prepare a new specimen and repeat.NOTE 1The percent nonvolatile content, N, at 105C may be deter-mined by drying dishes to constant weight and calculating as follows:N 5A 2 BS3 100 (1)where:A = weight of dish and specimen after heating,B
19、 = weight of dish alone, andS = specimen weight.6.4 Transfer the dishes to a muffle furnace and heat at 4506 25C for 1 h. Remove from the furnace, cool in a desiccatorand weigh.7. Calculation7.1 Calculate the percent pigment content, P, as follows:P 5C 2 BS3 100 (2)where:C = weight of the dish and s
20、pecimen after ignition in thefurnace,B = weight of the dish alone, andS = specimen weight.8. Precision and Bias58.1 Precision: Pigment ContentOn the basis of an inter-laboratory test of this test method in which eighteen operatorsin nine laboratories analyzed three materials containing threepigment
21、levels between 24 and 28 %, the within-laboratorystandard deviation was found to be 0.24 % absolute and thebetween-laboratories 0.38 % absolute. Based on these standarddeviations, the following criteria should be used for judging theacceptability of results at the 95 % confidence level:8.1.1 Repeata
22、bilityTwo results obtained by the sameoperator should be considered suspect if they differ by morethan 0.66 % absolute.8.1.2 ReproducibilityTwo results, each the mean of dupli-cate determinations, obtained by operators in different labora-tories should be considered suspect if they differ by more th
23、an1.05 % absolute.8.2 Bias: Pigment ContentOn the basis of the same study,the mean of two determinations should be within 5 % relativeof the formula pigment content of a waterborne paint contain-ing only inorganic pigments.8.3 Precision: Nonvolatile Content On the basis of aninterlaboratory test of
24、this test method in which fourteenoperators in seven laboratories analyzed three materials con-taining three nonvolatile levels between 43 and 48 %, thewithin-laboratory standard deviation was found to be 0.18 %absolute and the between-laboratories standard deviation wasfound to be 0.445 % absolute.
25、 Based on these standard devia-tions the following criteria should be used for judging theacceptability of results at the 95 % confidence level:8.3.1 RepeatabilityTwo results obtained by the sameoperator should be considered suspect if they differ by morethan 0.49 % absolute.8.3.2 ReproducibilityTwo
26、 results, each the mean of dupli-cate determinations, obtained by operators in different labora-tories should be considered suspect if they differ by more than1.23 % absolute.8.4 Bias: Nonvolatile ContentBias cannot be determinedbecause there are no accepted standards for nonvolatile contentin coati
27、ngs.9. Keywords9.1 low-temperature ashing; pigment content; water emul-sion paintsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the v
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29、omments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments ha
30、ve not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multipl
31、e copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1014.D3723 0512
