Transcription of Indian Standard
1 IS 50 DOC:CHD 20 (1858)C May 2011 Indian Standard SPECIFICATION FOR LEAD AND SCARLET CHROMES ( Fourth Revision ) BIS 2002 B U R E A U O F I N D I A N S T A N D A R D S MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 Price Group 4 1 FOR BIS USE ONLY DOC:CHD 20 (1858)C May 2011 BUREAU OF Indian standards Draft Indian Standard SPECIFICATION FOR LEAD AND SCARLET CHROMES ( Fourth Revision of IS 50) (Not to be reproduced without the permission of BIS or used as Standard ) Last date for receipt of comments is 23 08 2011 0.
2 F O R E W O R D (Formal clauses will be added later) This Standard was first published in 1950 and subsequently revised in 1963, 1980. In view of the nature and the variety of treating agents used in production of treated chromes it is impracticable to lay down composition of this type of pigments. However, limit for lead monoxide in the material has been given. The method for determination of lead monoxide (PbO) content has been replaced by the latest method prescribed in IS : 6947 (Part III)-1975*. The revision has been undertaken to incorporate the requirements of pH of aqueous extract, Light fastness test and Resistance to Acid & alkali to have a better idea about the performance.
3 PH measurement is necessary to ensure that pigment is washed properly during manufacturing and impurities of extreme pH will not have undesirable effect on paint. In view of this acidity and alkalinity tests are deleted in Table 1. Light fastness test is necessary as these lead chrome pigments are more vulnerable for darkening mainly due to formation of lead salts. Stability of Colour test is replaced by Light fastness test. Light Resistance against acid, alkali is necessary to ensure good chemical resistance of pigment ..Chemical resistance & light fastness tests are performance tests which depend on various aspects of manufacturing like surface treatments.
4 Particle size, shape etc. This Standard contains clauses , which call for agreement between the purchaser and the supplier. For the purpose of deciding whether a particular requirement of this Standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS : 2-1960(Rules for rounding off numerical values). The number of significant places retained in the rounded off value should be the same as that of the specified value in this Standard . 1. SCOPE This Standard prescribes requirements and methods of sampling and test for lead chromes treated lead chromes, and scarlet (molybdated) chromes used as paint pigments.
5 22 REFERENCES The standards listed in Annex A contain provisions which through reference in this text, constitute provisions of and necessary adjuncts to this Standard . At the time of publication, the editions indicated were valid. All standards are subject to revision and parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated in Annex A. 3 TERMINOLOGY For the purpose of this Standard , the definitions given in IS 33:992 and IS 1303:1983 shall apply. 4 REQUIREMENTS Form and Condition The material shall be in the form of dry powder or in such a condition that it is possible to reduce it to the powder form by crushing without grinding action, under a palette knife.
6 Composition The material dried as described under of IS 33:1992 shall consist of chemical precipitates of either normal or basic lead chromate or lead molybdate or mixture of these with or without other co-precipitated insoluble compounds of lead. The presence of white lead or lead carbonate is not permissible except if formed in situ during the manufacture of the chrome pigments. The amount of white lead or lead carbonate so formed and determined by the method prescribed in Annex B shall not exceed 5 percent by mass when expressed as lead monoxide (PbO). This limit, however, shall not exceed that for the sample approved against this specification, if any. The material shall be free from extenders or diluents, such as barium sulphate, clay, whiting, organic dyestuffs, etc.
7 In case of treated chromes, the pigment may contain other metallic compounds added specifically to improve pigmentary properties. In all such cases, the improvements obtained by way of treatment shall be stated by the supplier. Lead Content The total lead content in the material determined as lead monoxide (PbO) shall be minimum percent by mass. When tested as prescribed in 5 of IS 6947 (Part 3):1975. For Scarlet Chromes Only Molybdenum Content If required by the purchaser the molybdenum content of the material shall be determined by the method prescribed in Appendix C and the requirement for same shall be as agreed to between the purchaser and the supplier. The material shall also comply with the requirements given in Table 1.
8 5. PACKING AND MARKING Packing The material shall be suitably packed as agreed to between the purchaser and the supplier. 3 TABLE 1 REQUIREMENTS FOR LEAD AND SCARLET CHROMES (Clause ) SL CHARACTERISTIC REQUIREMENT METHOD OF TEST, NO REF TO CL NO. IN IS 33: 1992 Annexure (1) (2) (3) ( 4) (5) i) Volatile matter, percent 8 by mass, Max ii) Residue on sieve, 9 percent by mass, Max iii) Oil absorption 10 40 10 iv) Colour Close match to IS colours No.
9 11 354, 355, 356, 357, or 591, for primrose, lemon, golden yellow, light orange or deep orange, respectively whichever is required conforming to IS 5: 2004 or Close match to the colour of the approved sample, if any v) Staining power Not inferior to that of the approved sample vi) Tone Equal to that of the approved sample 12 vii) pH of 10 % aq suspension Annex F vii) Matter soluble in water, 19 percent by mass, Max viii)
10 Resistance to acids Close match to std Annex D ix) Resistance to alkali Close match to std Annex D x) Fastness to light Close match to std Annex E This shall, however, be within 10 percent of approved sample, if any. Marking The containers shall be marked with the following: a) Name of the material and additional information as per and , wherever applicable; b) Net mass of the material; c) Manufacturer s name and his recognized trade-mark, if any; d) Batch number or lot number in code or otherwise; and e) Month and year of manufacture.
