1. Material selection: Commonly used raw materials include wood pulp and waste paper. Wood pulp can be obtained by chopping wood, soaking, cooking and bleaching, while waste paper needs to be recycled and classified.
2. Pulping: After raw materials are crushed, soaked and cooked, cellulose begins to decompose. Chemicals such as alkaline oxides (such as sodium hydroxide) and sulfuric acid are added to the slurry to remove impurities and separate cellulose.
3. Screening: pour the slurry on the screen, water seeps out, and the fiber forms a paper layer on the screen. Screen usually consists of metal wires, and the size of the mesh determines the thickness of the paper.
4. Press: The moisture in the paper layer is further removed by the action of the press roller. This step helps to improve the density and strength of the paper.
5. Drying: expose the paper to hot air or solar energy to remove residual moisture. It is necessary to control the temperature and humidity in the drying process to ensure that the paper is dried evenly.
6. Surface treatment: According to needs, the paper can be surface treated to improve the texture and performance. Common treatment methods include coating, embossing and smooth treatment.
7. Cutting and packaging: use a cutting machine to cut a large piece of paper into the required size, and then package it. Packaging usually includes stacking or winding paper and protecting it with cartons or films.
The whole papermaking process needs to strictly control the process parameters of each link, such as pulp concentration, temperature, pressure, drying conditions, etc., to ensure the quality and performance of the paper meet the requirements.
Hemp paper in ancient books mainly includes the following:
1, white hemp paper: The paper of sprouting teeth in the Western Han Dynasty is the earliest plant fiber paper in China. At first, the whiteness of paper was poor, the surface was not smooth and the structure was not tight, so it could not be used for writing. It was used for writing in the Eastern Han Dynasty and became an important cultural paper in the upper class in the Sui and Tang Dynasties.
2, jute paper: white hemp paper becomes jute paper when it enters the Yellow River, which can repel insects. It is the earliest dyed paper in China, which started in Jin Dynasty and was widely used in Tang Dynasty.
3. Tibetan Scripture Paper: It was dyed with yellow tillers in the Tang, Song and Yuan Dynasties and was specially used for writing and engraving Buddhist scriptures, so it was called Tibetan Scripture Paper. Wherein hemp, bark and bamboo are used. There are two kinds of Tibetan scripture paper: thin paper is thicker than ordinary paper, and it is not waxed but not hard. As a bookmark for collecting precious and rare books.
4. Hard yellow paper: It began in the Tang Dynasty, dyed with yellow tillers and waxed on both sides. A famous paper specially used to copy Buddhist scriptures. In the Song Dynasty, it evolved into a glazed Jinsushan Tibetan Scripture Paper.