What are the factors that affect the whiteness of paper
Paper whiteness refers to the whiteness of the surface of the paper, that is, the ability of the paper to fully
reflect after being irradiated by light,expressed as a percentage. The quality standards of paper have clear
requirements for whiteness,so what are the factors that affect the whiteness of paper?
1.Whiteness of pulp
The whiteness of the pulp determines the basic whiteness of the paper. The whiteness of the pulp is high, and
the whiteness of the paper produced is also high.
2 The amount of filler added
The whiteness of general fillers (such as white earth, talc, calcium carbonate, titanium dioxide, etc.) is higher
than paper pulp, so adding fillers to the pulp can improve the whiteness of the paper. In paper production, due to
the different filler content on both sides of the paper, the whiteness of the two sides of the paper differs by 0.5
to 3.0 percentage points. When using white pigment for surface coating, the paper whiteness can be significantly
3.Effect of drying
Excessive drying of the paper, high temperature of the paper roll and long storage time will reduce the paper
4.Turbidity of white water for production
The whiteness of paper produced by clean water with low turbidity is higher than that of water produced by turbid
5.Pulp lignin content
The high lignin content in the pulp or excessive bleaching will cause the pulp to age and turn yellow, reducing
the whiteness of the pulp.
In addition to the above factors, must also be considered other factors that affect the whiteness of
paper, for example, the raw materials used for pulping, the design of the bleaching process, the design of
the deinking process etc.
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