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Factors Affecting The Whitening Effect Of Fluorescent Whitening Agent Used In Paper Industry

Sep. 16, 2019

Fluorescent  agent, commonly known as white dye, is a colorless or light-colored fluorescent  dye that absorbs ultraviolet light and emits visible blue-violet light,  resulting in a visual whitening effect. The whitening effect is to use the  optical complementary color principle, so that after the yellowing substance is  treated by the fluorescent whitening agent, not only the visible light but also  the ultraviolet light other than visible light can be absorbed and converted  into visible light having purple blue or cyan. Yellow and blue complement each  other, offsetting the original yellow color of the material, making it appear  white. There are many kinds of fluorescent whitening agents, mainly Fluorescent Whitening Agents For Detergents .They are also widely used in papermaking, textile and  other fields, among which the paper industry has the largest amount of  fluorescent whitening agents.

Factors Affecting The Whitening Effect Of Fluorescent Whitening Agent Used In Paper Industry

Optical Brightener For Paper Industry

Factors  affecting the whitening effect of Optical Brightener For Paper Industry

1. Metal ion  effect

The presence of  metal ions in the papermaking system can adversely affect the fluorescent  whitening agent, with Fe3+ having the greatest effect and producing insoluble  colored materials.

2. PH  effect

The whitening  effect of the fluorescent whitening agent is affected by the pH of the medium,  and the effect is good under medium and alkaline conditions. Therefore, the  water used for papermaking or paper machine should be as close to neutral as  possible, which is beneficial to increase the increase of fluorescent whitening  agent. White effect.

3. Effect of  retention aids and fillers

The cationic  polymer produces a quenching effect on the effect of the optical brightener,  thereby reducing the whitening effect of the disulfonic acid and tetrasulfonic  acid fluorescent whitening agents. When using fluorescent whitening agents and  retention aids, the addition position of the two should not be too close to  avoid reaction. In addition, different types of fillers have different effects  on fluorescent whitening agents. Commonly used fillers in papermaking are  calcium carbonate, talc and kaolin. Under moderate alkaline conditions, calcium  carbonate and talc have no negative effect on the fluorescent whitening agent,  which will enhance the effect of the fluorescent whitening agent.

4. Effect of  whiteness of puree

The higher the  whiteness of the puree, the more obvious the whitening effect after adding the  fluorescent whitening agent, and the brighter the color tone, when the whiteness  of the original pulp is lower than 65% ISO, the fluorescent whitening agent  almost loses the whitening effect.

5. Damage to  paper

The cationic  compound contained in the damaged paper will quench the fluorescent whitening  agent, and the whitening effect of the whitening agent is greatly reduced.  However, adding the fluorescent whitening agent to the primary slurry before the  paper is mixed can significantly improve the whiteness. Therefore, in the  production process, it is necessary to control the addition position of the  damaged paper, and to ensure the stable copying of the damaged paper, so as to  ensure the stability of whiteness and color tone.

6. Effect of the  amount of fluorescent whitening agent

On the basis of  a certain degree of whiteness, the whiteness of the pulp will increase to some  extent with the increase of the amount of fluorescent whitening agent. When the  amount of whitening agent reaches a certain level, the whiteness of the pulp  reaches the maximum; however, continue Increasing the amount of brightener will  reduce the whiteness of the pulp.


If you are  looking for more information about the products, feel free to contact us, who is  a professional Fluorescent Brightener Supplier.