1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-21737-2 SANS 5126:2008Edition 3 SOUTH AFRICAN NATIONAL STANDARD Viscosity of binders for paints Published by Standards South Africa 1 dr l
4、ategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 5126:2008 Edition 3 Change No. Date Scope Foreword This South African standard was approved by National Committee StanSA SC 5140.01B, Dete
5、rgents, polishes and other chemicals Detergents, soaps and cleaners, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This document was published in July 2008. This document supersedes SABS SM 126:1975 (first revision). SANS 5126:2008 Edit
6、ion 3 1 Viscosity of binders for paints 1 Scope This standard specifies a method for the determination of the viscosity of binders for paints. 2 Apparatus 2.1 Bubble viscosity test tube of clear glass and closed, flat, even bottom that has the following dimensions and markings. a) internal diameter
7、of 10,75 mm 0,025 mm; b) internal length of 112 mm 0,05 mm; c) an etched line round the outside of the tube 5 mm from the open end; and d) a second etched line round the outside of the tube, 13 mm from the open end. 2.2 Bubble viscosity tube holder with rack and pinion capable of inverting bubble vi
8、scosity test tubes and calibrated reference standard tubes 180 to within 1 of a vertical position. 2.3 Thermostatically-controlled water bath, capable of maintaining a temperature of 25 C 0,25 C. 3 Calibrated reference standard tubes A series of calibrated reference standard tubes, of the same dimen
9、sions and markings of those described in 2.1 and filled with transparent liquids that have predetermined viscosities and that are marked alphabetically with the long established Gardner-Holdt letter standards1as listed in table 1. 1Gardener-Holdt viscosity standard tubes are manufactured by BYK Gard
10、ner, Lausitzer Strasse 8, Geretsried, Germany and are commercially available from the World Wide Web http:/. This information is given for the convenience of users of this standard and does not constitute endorsement by Standards South Africa of the product named. SANS 5126:2008 Edition 3 2 Table 1
11、Gardner-Holdt letter standards for comparator viscosity bubble tubes 1 2 Viscosity a Gardner-Holdt letter Pa.s A 0,050 B 0,065 C 0,085 D 0,100 E 0,125 F 0,140 G 0,165 H 0,200 I 0,225 J 0,250 K 0,275 L 0,300 M 0,320 N 0,330 O 0,340 P 0,400 Q 0,440 R 0,470 S 0,500 T 0,550 U 0,627 V 0,884 W 1,070 X 1,2
12、90 Y 1,760 Z 2,270 aExtracted from ASTM D 1545-07 and BYK Gardner website data. 4 Sampling Take a laboratory sample as specified in the relevant product standard. Where no standard exists, take the laboratory sample as agreed upon between the test laboratory and the manufacturer to ensure a reasonab
13、le and acceptable reliability at a reasonable and acceptable confidence level. 5 Test specimen preparation 5.1 From the laboratory sample taken in accordance with clause 4, prepare a test specimen of approximately 150 mL by straining the test specimen through a fine filter paper to ensure that the t
14、est specimen is free from solid particles. 5.2 Fill a bubble viscosity test tube (see 2.1) with the filtered test specimen (see 5.1) that is free from air bubbles, to a level such that, when a cork stopper is inserted, the bottom of the cork stopper is level with the upper etched line on the bubble
15、viscosity test tube. SANS 5126:2008 Edition 3 3 6 Procedure 6.1 Knowing the approximate viscosity of the laboratory sample, select four calibrated reference standard tubes (see clause 3) closest in viscosity to the laboratory sample. 6.2 If the approximate viscosity of the laboratory sample is not k
16、nown, select the four calibrated reference standard tubes that, when inverted, produce moving air bubbles of substantially the same length as the air bubble produced by the inverted test specimen tube (see 5.2). 6.3 Insert the test specimen tube and selected calibrated reference standard tubes in th
17、e bubble viscosity tube holder (see 2.2) and immerse in the thermostatically controlled water bath at a temperature of 25 C 1,0 C (see 2.3). 6.4 Allow the viscosity tube holder and tubes to stand in a water bath for a minimum of 10 min before removal. 6.5 Remove the viscosity tube holder and tubes f
18、rom the water bath and immediately invert them. 6.6 Allow the viscosity tube holder and tubes to remain inverted for twice the anticipated time of traverse of the bubbles within the tubes, in order to bring the bubbles to complete rest in the inverted position. 6.7 Quickly turn the viscosity tube ho
19、lder and tubes back to the upright position and visually compare the rise time of the bubble in the test tube to the rise time of the bubbles in the calibrated reference standard tubes. 6.8 Record the Gardner-Holdt letter standard which most closely matches the test specimen tube in rate of bubble r
20、ise. 7 Test report Report the following information: a) all the data needed to identify the laboratory sample tested; b) confirmation that the test was carried out in accordance with this standard; c) any deviation from this standard; and d) the viscosity of the sample, in the Gardner-Holdt letter s
21、tandard representing the calibrated reference standard that most closely matched the rate of bubble rise of the specimen tested, but for viscosities greater than “U” (0,627 Pa.s), report the letters of the two calibrated reference standards of which the rate of bubble rise in each is respectively just above and just below that of the specimen tested. Bibliography ASTM D 1545-07, Standard test method for viscosity of transparent liquids by bubble time method. Standards South Africa
