From the perspective of raw materials. Cai Lun uses plant fibers, mainly waste hemp and bark, as raw materials to achieve the purpose of significantly reducing costs.
"Book of the Later Han Dynasty." "The Biography of Cai Lun" says, "Lun is a creative idea, using tree skin, hemp heads, poor cloth and fishing nets as paper." Among them, hemp heads, rags, and fish nets are all hemp fibers. The so-called hemp head refers to the waste rope ends or textile leftovers; the old cloth refers to the rags and old clothes of linen, because ancient clothes generally used linen; the fish net refers to the old fish nets that can no longer be used, and the ancient fish nets were woven Used is twine. So these three types are all waste products from hemp fibers. Cai Lun discovered that these discarded materials were actually more conducive to papermaking than new linen materials.
Tree skin is the bark of the tree, here it refers to the bark of the valley tree. Grain trees in China can grow in all parts of the north and south; the current scientific name is paper towel tree, and the ancients also called it Pu tree. The fiber of cereal bark is much finer and stronger than that of hemp. Starting from Cai Lun, valley bark became an excellent raw material for making high-quality paper. Therefore, the ancients called paper "Mr. Chu", or "Chu". However, the pectin and lignin contained in cereal bark are several times higher than those of hemp, so processing is particularly difficult. In addition to valley bark, mulberry bark was also an early high-quality raw material used for papermaking, but it is not found in the records about Cai Lun. Due to the difficulty of processing grain bark, Cai Lunzhao should have made a breakthrough in hemp papermaking before using grain bark.
It can be inferred from the number "Lun Nai Zai Yi" that using hemp fiber as raw material was not Cai Lun's creation, but using waste hemp fiber and corn bark as raw material was Cai Lun's creation. Focusing on the use of cheap plant fibers to make paper, it is possible to think of corn bark or other bark from hemp.
From a processing perspective. Cai Lun designed his own process based on the characteristics of plant fiber as a raw material and the requirements of manual workshop production, with the goal of giving products excellent performance.
Cai Lun produced paper in a handicraft workshop, and its processing technology can be verified by Liu Xi's words in "Release of Names":
Cai Lun, a regular servant in the imperial court, filed old cloth, pounded it, and copied it. Paper.
Many scholars in the history of science and technology believe that the three verbs related to handicrafts such as "file", "pound" and "copy" in "Shiming" generally represent Cai Lun's processing process. Liu Xi, the author of "Shiming", was born in Beihai County (the county is located southwest of today's Weifang City, Shandong Province) in the late Eastern Han Dynasty. At that time, his place was close to Cai Lun, so his theory is more credible. For another example, Hui Dong's "Collection of Later Han Scripts" quotes "Books of Jin" as follows: "Cai Lun filed, pounded old cloth and nets, and copied them into paper." Another example is Wei Zhangyi's "Ancient and Modern Character Exegesis" which says: "Zhong Changshi Cai Lun pounded and filed the old cloth to make paper. "Zhang Hua's "Natural History" of the Western Jin Dynasty said: "Cai Lun began to boil bark to make paper." The contents of these earlier documents are very similar and can complement each other without contradiction. Based on these records, the processing process of Cai Lun's papermaking can be explained as follows.
1. Cutting and degumming.
The "file" mentioned in "Shi Ming" and "Ancient and Modern Ziji" etc. means to cut or chop into pieces. According to "Shuowen": "To file, it means to break." "Yupian": "To file, it is to cut." In today's papermaking process, filing is roughly the same as cutting materials.
Papermaking raw materials are often too long to be processed; especially hemp, whose fibers are too long and cannot be cut into fine materials and cannot be processed into qualified paper. Therefore, rags, old clothes, fish nets, and tree bark all need to be chopped. Cutting can cut the fibers in the raw materials so that the fiber length meets the requirements of papermaking. This is both to facilitate degumming and for further processing.
Zhang Hua's "Natural History" said: "Cai Lun began to boil bark to make paper." Why does bark need to be "cooked" to make paper? The reason is that the bark cannot be degummed without boiling. This "initial cooking" proves that Cai Lun was the first to innovate the degumming process in papermaking. It also shows that he has the scientific and technological concept of consciously attaching importance to degumming.
Degumming is still one of the necessary processes for papermaking. The purpose of degumming is to separate the pectin and lignin in the hemp material or bark from the papermaking fibers in it. The ancient separation method usually involves repeated rinsing in running water after degumming is completed. Papermaking fibers should be pure and free of impurities, so degumming should be thorough.
Degumming of linen material is common sense among ancient Chinese people. "Book of Songs." "The Pond of the East Gate" says: "The Pond of the East Gate can be used for retting hemp." This retting is degumming using biological fermentation methods. It is common knowledge among women and children that when weaving fabrics with hemp yarn, the hemp must be retting beforehand. Therefore, Cai Lun used hemp material to make paper, and only needed to follow this method of retting hemp when degumming. Cai Lun first discovered that the fiber of the bark of the valley tree is an excellent raw material for papermaking. However, the difficulty of degumming bark is much greater than that of hemp material, so Cai Lun further invented a method of "boiling bark" to degumm. In folk retting, there is a method of adding alkaline materials such as plant ash to accelerate degumming. Since Cai Lun consciously attached importance to the scientific and technological awareness of degumming, he should continue to use this method, but there is no record to test it. In the papermaking process, the purpose of "cooking" is to degumm the raw materials quickly and completely through heating. After rinsing, pure papermaking fibers without impurities can be obtained.
Obtaining qualified and pure papermaking fibers through cutting and degumming is one of the key processes to improve paper performance.
2. Beat the pulp.
It is repeatedly mentioned in the literature that Cai Lun used the "pounding" method in papermaking. This pounding means pounding paper pulp, which has the same meaning as beating pulp in today's papermaking industry.
According to historical records, Cai Lun’s tool for pounding paper pulp was a stone mortar. Luo Han's "Xiangzhou Records" of the Jin Dynasty said: "There is Cai Lun's house in Huangmen, Han Dynasty in the north of Leiyang County. There is a stone mortar in the west of the house, which is said to be Lun's paper mortar." "Jingzhou Records" of Sheng Hongzhi of the Southern Dynasties and Song Dynasty: "A stone mortar in Zaoyang County A hundred steps away from Cai Lun's house, there is a mortar inside, which is called Cai Zichi. "This kind of stone mortar was originally a rice pounding tool that existed in the Han Dynasty. The stone mortar used to pound rice in the Han Dynasty was powered by human power, animal power, water power, etc. Cai Lun used a stone mortar to pound paper pulp, so it stands to reason that he could also use animal power and water power. Historical records often refer to the paper mortar as a symbol of Cai Lun's papermaking. It seems that the technology of pounding paper pulp was either pioneered by Cai Lun or matured in his hands. This is a remarkable breakthrough in papermaking technology.
Cai Lun pounded paper pulp based on the same technological principles as the pulping in current paper mills. Regarding Cai Lun's pounding, the history of papermaking science and technology commented this way:
pounding, that is, mechanical beating, is a key process that enables fibers to bond with each other to form paper sheets. ...(fibers after pounding) are dehydrated and dried to form paper with interwoven fibers and strength. To identify whether the unearthed flax or paper has been beaten, it depends on whether it has been beaten. Mechanical beating is a process that consumes a lot of power in the papermaking process. Cai Lun used the pounding method to solve this key and achieved success.
Cutting and degumming of plant fibers is the first successful step in the papermaking process. However, this alone cannot produce qualified paper. Fibers that have not been pounded cannot be tightly intertwined after dehydration and drying. As a result, the fibers are loose and lack the necessary strength. In this case, although the fibers can be laminated to form thin sheets and become paper-like objects, the fibers are loose and cannot withstand rolling and folding, and are highly permeable, making it impossible to write. Papermaking fibers can only be tightly and powerfully intertwined with each other after dehydration and drying. The paper thus formed can have a delicate surface, have the necessary strength, have appropriate water absorption properties, and become a paper that can be written on and is durable. Therefore, it is impossible to make qualified paper with papermaking fibers without sufficient pounding. This is the reason why Cai Lun's "pounding" in papermaking has been repeatedly emphasized in ancient literature.
Crushing pulp is another key process for Cai Lun to manufacture qualified paper and improve paper performance.
3. Papermaking and paper medicine.
The "chao" of "pounding and copying to make paper" mentioned in Liu Xi's "Shi Ming" of the Eastern Han Dynasty is the name papermaking that is still used in the papermaking industry today. This is the last important process in papermaking.
The tool used for papermaking is the papermaking curtain. The fully pounded fibers are evenly suspended in the water. Use a papermaking curtain to fish out fibers from the water. The fibers quickly filter water on the curtain and become wet paper pages. After drying, they become paper. It is said that people before Cai Lun may have used tools similar to papermaking curtains to make paper from broken silk floss. Xu Shen's "Shuowen Jiezi" (13) explains "paper" as "a thatch". The paper Xu Shen refers to is wadding paper.
This "thatch", that is, the thatch of a grass thatch, is a curtain woven from straw. Others say it is a curtain woven from thatch. People use it to fish out the silk and cotton fibers in the water to make wadding paper. Duan Yucai of the Qing Dynasty believed in "Shuowen Jiezi Annotation" that this "thatch" was a mistake, and then interpreted it as bamboo curtain. Professor Liu Guojun, an expert on calligraphy and history, agrees with Duan's theory. These comments are helpful. However, paper curtains can be made of straw or bamboo; perhaps straw is more commonly used in the north, while bamboo is more commonly used in the south. For papermaking, whether straw or bamboo, the common requirement for papermaking curtains is that the fibers can be scooped out evenly in the water, and the water in the fibers on the curtains can be quickly filtered. So, did Cai Lun use paper curtains? The answer is yes. Because not only "Shi Ming" but also "Book of Jin" quoted in "Collection of Later Han Scripts" says that Cai Lun "copied and made paper", this "copying" must refer to copying using a paper-making curtain, and there is no other possibility. Cai Lun's paper-making curtains are probably related to the "thatch" mentioned by Xu Shen. They may have been improved and innovated, but the specific situation is unknown.
In the papermaking process, another important process is the use of paper chemicals. Ancient paper medicine was a slimy juice extracted from certain fresh plants. After papermaking fibers are pounded, they become pulp. Only by adding paper chemicals to the pulp can the fibers be evenly suspended in the water without aggregation and sedimentation. The wonderful functions of paper medicine are: first, it promotes the fiber extracted by the papermaking curtain to be evenly distributed on the curtain to avoid uneven paper thickness; second, it makes the wet paper pages stacked together, and then pressed and dehydrated, so that they are inseparable from each other. There will be adhesion, but it can still be peeled off page by page. Therefore, it is impossible to make paper continuously without paper making curtain without paper medicine. Japanese paper history experts Professor Yamashita Toraji, Professor Toshi Yusho and other Chinese and foreign scholars all believe that paper medicine was invented by Cai Lun. This is believable. Because without paper medicine, the uninterrupted manual production of paper mills cannot be solved. It is possible to produce one or two sample papers in this way, but if you want to carry out continuous manual production without interruption, you must use paper medicine, and there is no second method. According to literature records, after Cai Lun invented "Caihou Paper", there was a situation where "everyone in the world did not use it". From then on, the imperial court began to supply the paper needed by officials, and literati across the country began to use the paper to copy and write letters. If the paper mills of the Eastern Han Dynasty did not use paper medicine, the production quantity must be very limited. How could there be such a lively situation as "everyone in the world does not use it"? How can we basically meet the needs of the whole country? Therefore, paper mills in the Eastern Han Dynasty starting from Cai Lun had to use paper medicine, and there was no other way. The problem of paper medicine should be solved by Cai Lun in Shangfang's paper mill production. This is an inference, and I believe it is a reasonable inference.
Papermaking curtains and paper chemicals are matched to provide key technologies for continuous and uninterrupted manual production in paper mills.
In summary, Cai Lun's papermaking process route, including raw materials and processing processes, has become a complete and mature production process technology. Relying on this production process, qualified paper "Caihou Paper" is produced in the workshop. Among them, there are three major issues that need to be solved technologically: first, reducing product costs; second, ensuring product performance and quality; and third, achieving continuous and uninterrupted production in paper mills. It is true that it is impossible for Cai Lun not to inherit and learn from other people's scientific and technological achievements. However, a complete and mature production process technology sufficient to solve the above problems did not exist before Cai Lun. Therefore, this complete and mature production process technology is Cai Lun's own invention and creation.