Upgrading Paper-Grade Pulp as Dissolving Pulp for Lyocell Fiber Preparation

Lyocell fiber has emerged as a new generation of green fiber due to its preparation process and unique properties in comparison with viscose fiber. The raw material for the preparation of Lyocell fiber has a great impact on the quality of the finished product. However, unlike viscose-grade dissolving pulp, there is no evaluation system for Lyocell-grade dissolving pulp, making it difficult to assess the quality of the raw material. This study examined the approach to upgrade the paper-grade pulp to dissolving pulp for the preparation of the raw material for Lyocell fiber. Under the sequence of caustic extraction, acid treatment, and enzymatic treatment, the pulp was prepared with competitive properties compared to the commercial Lyocell-grade dissolving pulp. The assessment of prepared pulp was also accomplished by characterizing the pulp properties, the dissolution properties, and the spinnability and stability of Lyocell solution using the prepared sample. In addition, the dissolution mechanism and influencing factors of pulp in the system were elucidated, providing a theoretical basis for upgrading paper-grade pulp to dissolving pulp for Lyocell fiber production.