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Understand the wood pulp industry from scratch


What is wood pulp? I believe that even if you can't immediately present it in your mind, you can immediately list its uses. First of all, the indispensable tissue in our daily life is made of it as the main raw material. In addition, as a large paper towel consumer, China has a huge demand for wood pulp. As a kind of pulp made from wood, wood pulp can also be divided into many types according to its pulping materials, pulping methods and pulping uses. This explains that although the main raw materials of different paper towels on the market are wood pulp, the feel and other aspects will be different. In order to make you better understand wood pulp, I will briefly introduce some relevant knowledge and development prospects as a wood pulp practitioner for you to learn and exchange.

Overview of wood pulp products

1. In addition to papermaking, wood pulp is also widely used in other industrial sectors. And the selected trees will be different according to different application scenarios. Generally speaking, softwood trees widely used include spruce, pine, fir, larch and hemlock. Hardwoods such as eucalyptus and birch are also commonly used by many industrial manufacturers.

2. Secondly, we will classify wood pulp according to its manufacturing process. It is divided into mechanical wood pulp (ground wood pulp) and chemical wood pulp. Chemical wood pulp can be divided into sulfate wood pulp and sulfite wood pulp due to the use of different cooking agents. Let's talk about the differences between these types:

Mechanical wood-pulp: mechanical wood pulp, also known as ground wood pulp, is a pulp made of fiber raw materials by mechanical grinding. It occupies an important position in the paper industry. It has the advantages of low production cost, simple production process, strong ink absorption, high opacity and soft and smooth paper. Suitable for printing requirements. However, due to the short fiber and high content of non cellulose components, the paper strength is low. In addition, because most of the lignin and other non cellulose in the wood have not been removed, the paper produced with it is easy to turn yellow and brittle and cannot be preserved for a long time.


Mechanical wood pulp usually refers to white mechanical wood pulp and brown mechanical wood pulp. White mechanical wood pulp is mainly used to produce newsprint. It can also be mixed with other pulp to make writing paper and printing paper; Brown mechanical wood pulp is mostly used in the production of packaging paper and paperboard, especially industrial paperboard.

Sulphate wood-pulp: sulphate wood pulp uses the mixture of sodium hydroxide and sodium sulfide as the cooking agent. In the cooking process, because the medicine liquid is gentle and the fiber is not strongly eroded, it is strong and strong. The paper made has good folding, breaking and tearing strength. It can generally be divided into bleached and unbleached. Unbleached kraft wood pulp can be used to make kraft paper, paper bag paper, kraft board, general packaging paper and paperboard. Bleached kraft wood pulp can be used to make high-grade printing paper, newspaper painting, offset printing paper and writing paper.

Sulfite wood-pulp: sulfite wood pulp uses the mixture of sulfite and acid sulfite as the cooking agent The pulp has long fibers, soft properties, good toughness, high strength, easy bleaching and excellent weaving ability. According to the degree of refining, it can be divided into unbleached, semi bleached and bleached. Unbleached pulp is yellow because it contains a small amount of lignin and colored impurities, and the fiber is also hard. It is mostly used to make medium printing paper, thin packaging paper, translucent paper and oil proof paper.

According to the classification of beating characteristics, wood pulp fiber can be divided into coniferous wood and broad-leaved wood

For the pulp obtained by the same pulping method, softwood and hardwood can obtain similar physical strength when the beating degree of hardwood is higher than that of softwood. However, the fiber of hardwood pulp is short, generally 0.8-1.1 mm. We should not only improve the beating degree, but also try to avoid cutting too much fiber. Therefore, the broad-leaved wood pulp should be beating with lower beating specific pressure and higher beating concentration. The fiber of coniferous wood pulp is long, generally 2-3.5 mm. It is not suitable to cut too much fiber in the production of cement bag paper. However, when it is used to produce some medium and thin paper, such as typing paper, oil seal paper, etc., it needs to be cut to 0.8-1.5 mm to meet the requirements of paper evenness. Therefore, the beating process conditions can be determined according to the requirements of paper type.

Development status of wood pulp in China

According to the report on in-depth market research and development prospect prediction of China's wood pulp industry from 2020 to 2025 issued by xinsijie Industrial Research Center, as a subdivided product of pulp, the wood pulp industry has been in a stable development trend in China, Although the output has been reduced in the past two years due to the national "de capacity" and increasingly stringent environmental protection policies, the market application demand is still high. According to the relevant data released by China Paper Association, the total output of wood pulp produced in China reached 12.68 million tons in 2019, an increase of 10.6% over 2018, accounting for 18% of the total domestic pulp, which is the second largest pulp category after waste pulp.

From the market distribution of wood pulp, China's current enterprises engaged in wood pulp, such as Hainan Jinhai, Zhanjiang Chenming and Asia Pacific Shenbo, account for more than 50% of the wood pulp market alone. However, with the continuous expansion of the market, the demand is increasing. The supply of domestic forest resources is far from meeting the consumption demand of wood pulp. Therefore, China still needs to import from abroad.

From the relevant data released by the General Administration of Customs of China, we can also see that the import volume of wood pulp in 2019 reached 26.229 million tons, an increase of 7.4% over the previous year; By July 2020, China's wood pulp imports had reached 16.085 million tons, an increase of 8.8% compared with the same period of the previous year. The demand for wood pulp is constantly expanding, and domestic wood pulp enterprises have great potential to change the current situation of over dependence on imports.

Nowadays, the domestic machinery manufacturing industry is gradually transformed and further upgraded, and the requirements for wood pulp will also be improved. Price war alone is difficult to deal with the impact from import enterprises. Domestic enterprises should keep in mind & ldquo& Rdquo; Iron needs to be hard & ldquo& Rdquo; Further upgrade the wood pulp production process and material selection, so that the wood pulp can be recognized by the market with the characteristics of high strength and good toughness.


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