Papermaking process

Taking the method of making bamboo paper recorded in the ancient China classic "Tiangong Kaiwu" as an example, this paper introduces it. In ancient times, the steps of making paper with bamboo were as follows:

First, cut bamboo and float pond.

Chop tender bamboo, put it in a pond, soak it for more than 100 days, decompose it with natural microorganisms, and wash off the green skin of bamboo.

Second, cooking is too slow.

Put the bamboo obtained above into a bucket and cook it with lime for eight days and eight nights.

Third, mortars.

Take out the treated bamboo, put it in a stone mortar and beat it with a stone hammer until it is smashed into mud.

Fourth, put the material in the curtain.

Pour the mashed bamboo material into the sink and swing the material in the water with a bamboo curtain. The bamboo material becomes a thin layer and sticks to the bamboo curtain, and the remaining water flows into the water tank from the four sides of the bamboo curtain.

V. Curtain pressing paper

Then repeatedly through the curtain, so that the wet paper falls on the board, that is, to form a piece of paper. In this way, the steps of placing materials and covering curtains are repeated, so that thousands of wet papers are stacked, and the boards are added to squeeze out most of the water.

Six, drying by fire

Spread out the wet paper one by one and bake it. The equipment for baking paper is to build an alley with adobe bricks and make a fire in the alley. After the temperature of adobe brick rises, wet paper is pasted one by one and baked. After drying, the paper is obtained by uncovering the cover. Modern papermaking procedures can be divided into pulping, preparation, papermaking, processing and other main steps:

I. Pulping process

Pulping is the first step in papermaking. Generally speaking, there are three ways to convert wood into pulp: mechanical pulping, chemical pulping and semi-chemical pulping.

Second, the modulation process

The preparation of paper is another key point in papermaking, and the strength, color tone, printability and shelf life of the finished paper are directly related to it.

The common brewing process can be roughly divided into the following three steps: 1. Pulping; 2. Beating; 3. Bonding and filling.

III. The main job of the process papermaking department is to evenly interweave and dehydrate the tissue paper, and then dry, calender, roll paper, cut, sort and package it, so the general process flow is as follows:

1. Paper screening: the prepared paper is diluted to a lower concentration, and impurities and undissociated fiber bundles are screened again with the help of screening equipment, so as to maintain the quality and protect the equipment.

2. Mesh part: make the paper flow out of the headbox on the circulating copper wire mesh or plastic mesh and evenly distribute and interweave.

3. Press part: The wet paper removed from the mesh surface is introduced between two rollers with felt cloth. Through the extrusion of the rollers and the water absorption of the felt cloth, the wet paper is further dehydrated, making the paper more compact, thus improving the paper surface and increasing the strength.

4. Dryer: Because the moisture content of the pressed wet paper is still as high as 52%~70%, it can no longer be pressed out by mechanical force, so let the wet paper pass through the surface of many dryers filled with hot steam to dry the paper.

5. Roll paper: The roll paper is rolled into a paper roll by a roll paper machine.

6. Cutting, sorting, and packaging: Take a plurality of paper rolls that are rolled into a cylinder at the front, cut them into pieces with a paper cutter, then manually or mechanically sort out the damaged or soiled papers, and finally pack every 500 sheets into a package (usually called a ream).