GB/T 5211.7-1985 Determination of alkali resistance of pigments GB/T5211.7-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Method for the determination ofresistance to alkali of pigmentsThis standard is a general test method for pigments, used to determine the alkali resistance of pigments. 1 Definition
UDC 667.622
:667.613.5
GB 5211.785
When a pigment comes into contact with an alkali solution, the pigment and the alkali will cause the solution to stain and the pigment itself to change color. The alkali resistance of a pigment refers to the ability of the pigment to resist the effect of the alkali and cause the alkali solution to stain and the pigment to change color. 2 Materials and Instruments
2.1 Sodium hydroxide GB629-81: chemically pure, 2% solution. 2.2 Days: 0.001g.
2.3 Test tube: 25ml capacity, with ground stopper. 2.4 Electric oscillator: Oscillation frequency 280±5 times/min, oscillation amplitude 40±2mm. 2.5 Filter paper: Slow speed, should comply with the provisions of GB1915-80 "Qualitative filter paper". 2.6 Fine-pore crucible: Capacity 25ml.
2.7 Filter bottle: Capacity 125ml.
2.8 Colorimeter: Thickness 0.5cm, height 6.4cm. 2.9 Colorimeter stand: The colorimeter stand should have two holes, just enough to insert two colorimeter dishes, and the background should be white. Gray grading card: Use the gray grading card for staining of GB251-84 "Gray sample card for evaluating staining" and the gray grading card for fading of GB250-84 "Gray sample card for evaluating discoloration". 2.10
3 Determination steps
Two replicates of the test are required.
3.1 Preparation of test solution and filter cake
Weigh two portions of pigment sample, 0.5g each, accurate to 0.001g, and place them in test tubes (2.3), add 20ml of distilled water to one tube, and add 20ml of 2% sodium hydroxide solution (2.1) to the other tube, cover with ground stopper, fix horizontally on electric oscillator (2.4), shake for 5min, remove, pour into fine-pore crucible (2.6) covered with 3 layers of filter paper (2.5), and vacuum filter until clear filtrate is obtained. Note: If clear filtrate cannot be obtained by filtering with filter paper, other filtering methods can be used, such as glass filter. 3.2 Evaluation of staining and discoloration levels
3.2.1 Fill the cuvette (2.8) with 2% sodium hydroxide solution (2.1) and the clear filtrate obtained, respectively, and place the cuvettes (2.8) in the holes of the cuvette holder (2.9). Under natural light facing north, with the incident light at a 45° angle to the object being observed and the observation direction perpendicular to the surface of the object being observed, visually evaluate the staining level of the filtrate by comparing it with the gray scale card (2.10). 3.2.2 Take out the filter cakes from the two crucibles after filtration, place them on a white porcelain plate, press on a colorless glass, and visually evaluate the discoloration level of the pigment by comparing it with the gray scale card (2.10) in the same way as in 3.2.1. 3.3 Test results
The levels obtained by parallel tests should be the same.
National Bureau of Standards 1985-07
—16 Issued
1986-03-01 ImplementationbzxZ.net
Results Expression
GB 5211.7-—85
The alkali resistance of the pigment is expressed by the staining level of the filtrate, the color change level of the filter cake, or by both the staining level of the filtrate and the color change level of the filter cake. The best alkali resistance of the pigment is level 5, and the worst is level 1. The staining degree of the filtrate is between the two levels, which is expressed as 4-5, 3-4, 2-3, and 1-2. The color change degree of the filter cake is between the two levels, which is expressed as 4/5, 3/4, 2/3, and 1/2. If the staining degree of the filtrate and the color change degree of the filter cake are expressed at the same time, it is expressed as AB］, A represents the staining level of the filtrate, and [B] represents the color change level of the filter cake.
Note: For example, if the staining of a pigment filtrate is level 5 and the color change of the filter cake is 4/5, it is expressed as 5 [4/5]. 5
Test report
The test report should include the following contents:
The type and name of the test sample,
The alkali resistance level of the obtained pigment;
Abnormal phenomena occurred during the test;
The test period and test personnel.
Additional notes:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and is under the jurisdiction of the National Technical Committee for Standardization of Paints and Pigments. This standard was drafted by the 4th Working Group of the Technical Committee for Standardization of Pigments Inspection Methods. The main drafters of this standard are Shen Yaoliang, Suo Yunxia and Ma Jiang. 1193
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