Offset paper PH value measuring method

1, the paper overall PH value assay

The paper was first soaked in distilled water, then the aqueous solution was withdrawn and its pH was measured with a pH meter. This method has a certain reference value for paper and cardboard other than coated paper.

2, paper surface PH value assay

1 electrical test

Measure the potential difference between the indicator electrode and the reference electrode in the solution. The potential of the reference electrode is a constant value. The potential of the indicator electrode varies with the pH value of the measuring solution. At this time, the pH value meter is used to directly measure the solution. The PH value.

2-color ratio method

In the determination, the surface of the paper is first moistened with distilled water, and then acid-base indicator is dropped on the surface to observe its color change and compared with a color sample of known pH.

3 titration

The pH of the paper is represented by the pH of the proof solution. The acidity of an acidic solution is expressed as a fraction of sulfuric acid, and the alkalinity of an alkaline solution is expressed as a fraction of sodium hydroxide.