Manufacturing Process and Quality Control of Sulfur-Free Paper

The protective effect of sulfur-free paper directly depends on its manufacturing process and quality control. The production of high-quality sulfur-free paper typically involves the following key steps:
1. Raw Material Selection: High-purity plant fibers such as pure cotton and linen are used as raw materials, avoiding wood pulp containing lignin and hemicellulose (which easily produce acidic substances).
2. Alkaline Treatment: Alkaline substances like calcium carbonate and magnesium carbonate are added during pulp preparation to neutralize potential acidic substances and serve as long-term pH buffers.
3. Metal Ion Removal: Chelating agents are used to remove metal ions (such as iron and copper) from the pulp, as these ions can catalyze oxidation reactions and accelerate paper aging.
4. Strict Production Environment Control: Production is carried out in a sulfur-free and low-dust environment to prevent the introduction of external pollutants.
5. Quality Inspection: Methods such as pH value measurement, sulfur content analysis, and accelerated aging tests are used to ensure sulfur-free paper meets relevant standards.
Internationally, the quality requirements for sulfur-free paper mainly refer to ISO 9706 and ANSI/NISO Z39.48 standards, which specify key indicators such as pH value, alkaline reserve, and paper strength.

Applications of Sulfur-Free Paper

Sulfur-free paper is widely used in many fields, especially in cultural heritage protection areas such as art, museums, and libraries. It is commonly used for making covers, inner pages, and packaging for important documents and items such as books, albums, artworks, family trees, and archival records. Its main role is to provide protection during long-term storage or display, preventing acidic substances from damaging the quality and appearance of items.
In addition to preventing the generation of acidic compounds, sulfur-free paper also has excellent durability and stability. It can effectively reduce issues caused by acidic substances, such as fading, yellowing, and brittleness of paper. Meanwhile, sulfur-free paper has good moisture absorption performance, which balances the humidity difference between the paper and the environment to prevent deformation due to humidity changes.