GB/T 3780.1-2015Carbon black—Part 1: Test method for iodine adsorption number (English PDF)

Foreword

GB/T 3780 "carbon black" is divided into the following parts.

- Part 1. Test methods for iodine absorption number;

- Part 2. Determination of oil absorption number;

- Part 4. Determination of oil absorption number of compressed sample;

- Part 5. Determination of specific surface area - CTAB test method;

- Part 6. Determination of tinting strength;

- Part 7. Determination of pH value;

- Part 8. Determination of heating loss;

- Part 10. Determination of ash;

- Part 12. Inspection of impurity material;

- Part 14. Determination of sulfur content;

- Part 15. Determination of light transmittance of toluene extract;

- Part 17. Indirect determination of particle size Reflectance method;

- Part 18. Standard test methods for evaluation in natural rubber (NR);

- Part 21. Determination of sieve residue for rubber compounding ingredients - Water washing method

This part is part 1 of GB/T 3780.

This part is drafted in accordance with the rules given in GB/T 1.1-2009.

This part replaces GB/T 3780.1-2006 "Carbon black - Part 1: Test method for iodine absorption number". As compared with GB/T 3780.1-2006, the main technical changes are as follows.

- MODIFY the "carbon black sampling amount" (SEE Table 1; Table 1 of 2006 version);

- ADD the "iodine solution, c (1/2 I2) = 0.4730 mol/L, SEE A.1.1 for the preparation" (SEE 4.1);

- DELETE the mercury iodide (4.1 of 2006 version);

- ADD "Note 1" (SEE 4.2);

- ADD "Note 2" (SEE 4.2);

- DELETE the "Method B" from the "analysis procedure" in the prevision version (8.3 of 2006 version);

- MODIFY the description of the "blank test" in the "analysis procedure" [SEE 8.5c); 8.2.4.1.5 of 2006 version];

- DELETE the calculation equation from the "calculation results" of the "B method" in the previous version (SEE 9.2 of 2006 version);

- ADD the "adjustment of sodium thiosulfate standard solution" and the "adjustment of iodine solution concentration" (SEE A.2.1.1.3, A.2.2.1.3);

- ADD the "calibration with standard reference carbon black" and the "standard reference carbon black INR iodine absorption number control limit" (SEE A.3, A.4, Table A.1);

- DELETE the "SRB6 series standard reference carbon black iodine absorption literature value" (Appendix C of 2006 version);

- ADD the "determination of potassium iodide content" (SEE Appendix B).

This part is, through the re-drafting method, compiled with reference to ASTM

D 1510-11 "Carbon black standard test method - iodine absorption number".

As compared with ASTM D 1510-11, this part has many structural adjustments.

In Appendix C, it lists the clause comparison between this part and ASTM D 1510-11.

The technical differences between this part and ASTM D 1510-11 AND their causes are as follows.

- MAKE reference to the Chinese national standard GB/T 3778, GB/T 3782, GB/T 15338 as corresponding to the D 4483, D 1799, D 1900, D 4821 which are referenced in ASTM D 1510-11; ADD GB/T 8170, GB/T 12805, GB/T 12806, and GB/T 12808, in order to facilitate Chinese standard users (SEE Chapter 2);

- DELETE "meaning and application", which is not preferable to be included into the standard text (SEE Chapter 4 of ASTM D 1510-11);

- MODIFY "When replacing equipment or newly purchasing a large amount of iodine or sodium thiosulfate, OR both cases occur, the regression equation shall be redefined" into "When replacing equipment OR using different batches of iodine or sodium thiosulfate OR the sodium thiosulfate solution is stored for 30 d, it shall re-test the standard reference carbon black to confirm the regression equation", which is more comprehensive and clear (SEE A.3.6; 8.6 of ASTM D 1510-11);

- ADD "Laboratory may choose other standard reference carbon blacks with the same effect", in order to improve operability (SEE A.3.2 note);

- ADD "Standard reference carbon black INR iodine absorption number control limit" to facilitate standard users (SEE A.4, Table A.1);

- ADD "Structural changes of this part as compared with ASTM D 1510-11" (SEE Appendix C).

1 Scope

This part of GB/T 3780 specifies the method for determining the iodine absorption number of carbon black and acetylene black for rubber.

This part applies to all kinds of rubber carbon black (not including S series, mixed gas and natural gas tank carbon black) and acetylene black. It is not suitable for carbon black with surface porosity, volatility and the presence of extract.

2 Normative references

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this Standard.

GB 3778 Carbon black for use in rubber products

GB/T 3782 Acetylene black

GB/T 8170 Rules for rounding off for numerical values & expression and judgment of limiting values

GB/T 12805-2011 Laboratory glassware - Burettes

GB/T 12806-2011 Laboratory glassware - One-mark volumetric flasks

GB/T 12808-1991 Laboratory glassware - One mark pipettes

GB/T 15338 Carbon black - Validation of test method precision and bias

- ADJUST the switch to the liquid filling position, so that the burette is filled with sodium thiosulfate standard solution; USE this solution to rinse the inlet and the liquid delivery tube.

- ADJUST to the titration position; MAKE the counter back to zero; and USE thin paper to wipe the tube tip clean.

- USE the (4 ± 0.5) mL/min sodium thiosulfate standard solution for titration of the clear iodine solution until it changes into light yellow; USE water to rinse the tube tip and bottle wall. ADD 5 drops of starch solution;

- RECORD the burette reading, accurate to 0.01 mL. […]

8 Analysis procedures

8.5 PIPETTE 20 mL of the clear liquid in a 150 mL iodine flask, and USE sodium thiosulfate standard solution to conduct titration in accordance with the following a) or b).

a) Titration with digital burette.

CONTINUE dropping the sodium thiosulfate standard solution until the blue color is approximately disappeared; USE water to rinse the tube tip and bottle wall again; ADJUST the counter to make its increment of 0.01 mL/s ~ 0.02 mL/s; CONTINUE dropping until the solution just becomes colorless, which is the end point. […]