How is paper made?

It is generally believed that China's papermaking began in 105, and Cai Lun was the ancestor of papermaking, but this is not entirely correct. In fact, the invention and application of paper were far before this. Of course, Cai Lun is also very important for the promotion and improvement of papermaking in China. He replaced the raw silk filler with cheap and easily available materials such as bark, rags and fishing nets. Because of the rich sources of materials, the output of paper is greatly increased, and then it is extended to ordinary people. The improvement of various papermaking technologies in later generations was mostly promoted according to Cai Lun's method.

The most detailed works about papermaking are recorded in Song Yingxing's Heavenly Creations in Ming Dynasty. 13 The records of paper, bamboo paper and leather paper in "Killing Green" can be said to be a summary account of the development of traditional papermaking in China. This can be divided into five steps:

Split bamboo floating pool

1 step is "splitting bamboo and floating pond". The so-called "killing green" is named after chopping bamboo as raw material. Bamboo is one of the important sources of ancient papermaking. Therefore, southern China, especially Fujian, which is rich in bamboo, is the main producing area of bamboo paper, and Hsinchu with branches and leaves is the most suitable for papermaking. Papermakers usually go up the mountain to cut bamboo before and after the awn seeds, each bamboo is cut into 5 to 7 feet long, and then a pond is dug on the spot, and the cut bamboo is soaked in the pond 100 days. When it was taken out, it was washed vigorously to remove the green shell and bark to soften the bamboo.

/kloc-in the 0 th and 9 th centuries, the material source of papermaking changed from rags to wood, because wood is easy to obtain and has low cost. However, because wood fiber is composed of lignin, lignin will be oxidized, which is the cause of paper yellowing, and adding acid agent will aggravate this problem when making paper.

Zhu Mu Huang Zuhuo

The second step of making bamboo paper in Wu Kai of Tiangong is to mix bamboo and lime, and then soak them in wooden barrels for 8 days and nights. Lignin, gum, resin and other impurities in the raw materials were removed after alkali cooking. Then take out the cooked raw materials and rinse them in a clear water pool, then put them in a pot and soak them in lime water to cook them, and repeat this for more than ten days. After repeated cooking and rinsing, bamboo fiber gradually decomposes.

Nowadays, caustic soda has been used to replace limewater for pulping. Caustic soda is alkaline, which can decompose wood fiber quickly. In addition, chlorine is added to remove impurities in wood pulp for bleaching, but the discharged wastewater contains organic chlorine, which is very harmful to the ecological environment. At present, the paper industry has invested a lot of money to remove toxins and study new bleaching methods, such as replacing them with chlorine dioxide to reduce the production of organochlorine.

Swing the material into curtains

The third step in ancient papermaking was to take out the cooked raw materials and put them into a stone mortar to mash them into mud. The mashed raw materials are mixed with a proper amount of water, so that the fibers are completely separated and saturated with water to form a suspension of paper fibers, and then poured into a paper can. Then the paper is filtered in the pulp with a thin bamboo curtain, and the paper fibers are left on the bamboo curtain to form a paper film.

This process is the most laborious in papermaking. Papermakers stood by the paper trough, repeating actions such as scooping water and lifting bamboo curtains, with a load of 20 kg each time. In addition, fishing for paper depends on experience. If you copy light paper, it will be too thin, if you copy heavy paper, it will be too thick. It all depends on the skill of the craftsman.

Curtain pressing paper

Put the pulped bamboo curtain upside down on the pressure plate, and then carefully remove the bamboo curtain, and this paper film will fall on the board. Fold up layers of paper slowly, and then squeeze with a heavy object to drain the water from the paper. Under the pressure of heavy objects, the paper film gradually forms a square piece of paper. Each craftsman can only make 300 to 500 pieces of paper by hand every day. A machine in a modern paper mill produces tons of paper rolls every day. According to statistics, today's global paper mills produce more than 300 million tons of paper every year, which is equivalent to three times the total weight of global automobile production.

Bake by fire

Baked paper lane is a brick wall made of two adobe bricks, and there is a gap between the bricks to let the hot air out. When baking paper, first make a fire in the alley, and then spread the wet paper on the wall with thin copper tweezers. The hot air from the gap makes the paper dry slowly, and when it is dry, it is usable paper.

Mechanical papermaking allows people to fully enjoy the convenience of life, but a lot of waste paper is nerve-racking. 1995, the United States made a statistic and found that the average paper consumption of Americans in a year was 332 kilograms. People think that the use of paper will decrease after the arrival of the computer century. As a result, environmentalists are very disappointed. The use of paper has not decreased, but has increased. In addition to waste paper recycling, scientists are also studying various new uses of old paper, such as producing building materials with waste paper as the main raw material, hoping to reduce the amount of logging by human beings.

There are detailed pictures in the link.