PAPER MAKING TECHNOLOGY

1. Main Raw Materials (Fiber Materials)

1.1 Plant Fibers

These are the core materials for papermaking and come mainly from:

Wood (Wood Fiber) — Most Common

• Softwood (e.g., pine): Long fibers, high strength; ideal for producing strong paper (e.g., printing paper, packaging paper).

• Hardwood (e.g., eucalyptus, poplar): Short fibers, softer; suitable for smoother paper (e.g., writing paper).

Non-wood Fibers (Grass Fibers)

• Bamboo: Medium-length fiber; a good alternative to wood.

• Straw, rice straw, bagasse (sugarcane residue): Shorter fibers; commonly used in low-grade paper or regions with limited wood resources.

Recycled Fibers (Recovered Paper)

• Old newspapers, cardboard, books, etc.: Processed (e.g., de-inked) and reused. Recycled fiber is now a vital part of modern paper manufacturing.

2. Additives (Auxiliary Raw Materials)

These materials are used to improve paper performance, increase yield, or reduce costs.

2.1 Fillers

• Improve brightness, smoothness, and printability.

• Common types:

  • Calcium carbonate (CaCO₃)

  • Kaolin clay

  • Talc

2.2 Sizing Agents

• Increase paper's water resistance and improve print performance.

• Common types:

  • Rosin size

  • AKD (alkyl ketene dimer)

  • ASA (alkenyl succinic anhydride)

2.3 Strength Agents

• Improve wet and dry strength of the paper.

• Common: Polyamide, polyamine, etc.

2.4 Dyes and Optical Brighteners

• Used to enhance paper color (e.g., letterhead, label paper) and whiteness.

3. Other Chemicals Used During Production

• Bleaching agents: Such as hydrogen peroxide, sodium hypochlorite, chlorine dioxide (used for bleaching wood pulp)

• pH regulators: Such as lime, sulfuric acid

• Defoamers and preservatives: For better production environment and product stability