Paper machine manufacturers tell you why the paper will turn yellow after a long time

        Why does the paper turn yellow after a long time?

        In people's life experience, most papers and books will turn yellow after being stored for a long time. Are you wondering why the paper will turn yellow after being stored for a long time?

        In fact, the main reason is that the wood element is oxidized.

        What is wood element?

        Lignin is not a single compound, but a generic term for aromatic polymers. Aromatic polymers are widely found in plants and contain structural units of oxyphenylpropanol or its derivatives. Because it contains an electronic cloud structure with a conjugated double bond in the aromatic ring, it has its own color. The common lignin is yellowish brown, so the cross section of the wood is yellow.

        Why does the paper turn yellow?

        In fact, it is because pulp does not completely remove lignin from plants during the production process. Some papers, such as newsprint, also retain a large amount of lignin. The lignin will naturally oxidize and the color will become darker. It seems that the paper will turn yellow.