I am often asked why impurities sometimes appear in the final product. Despite our strict quality control, impurities can still occasionally arise from several key stages in the production process:
Raw Material Quality
Pulp source: If the wood pulp contains bark, soil, or sand that was mixed in during logging or slicing and is not completely removed during the pulping process, these impurities will remain.
Recycled fibers: When using recycled paper, residues such as adhesives (sticky residues), ink, or plastic fragments may not be completely removed during the deinking and screening processes.
Process Residues
Chemical additives: Some fillers (such as calcium carbonate, clay) or sizing agents, if not evenly dispersed, may form spots or lumps.
Machine deposits: Over time, deposits of pulp fibers, resins, or microorganisms can accumulate on machine parts and may later fall onto the paper.
Water System
The closed water circulation system in modern paper mills sometimes leads to the accumulation of dissolved solids or microorganisms, which may eventually form spots or slime on the paper.
Coating and Processing
Dust generated during slitting or cutting operations may embed in the paper surface.
Improper cleaning between batches or grade changes may leave residues from the previous batch of materials.
If you have any needs pls contact me!
whatsapp\phone: +8618933586483
Email: 03@songhongpaper.com
Wechat: helen18933586483