In recent years, the technical term of the dissolving pulp has come into the eyes of the colleagues in the industry of the pulp and paper making with the tremendous momentum and been highly valued by them.
The Reason of Rapid Rise of Dissolving Pulp Demand
The reason lies in the market feedback for cotton industry. The insufficient cotton supply and sharply rising prices bring the manufacturers the insufficient supply of cotton linter, resulting in surging cost pressure for the downstream textile industry. Improving the ratio of cotton substitute to reduce that has the choice of many manufacturers. Thus, the content of viscose fibers has gradually increased in China, which pushes the dissolving pulp to rapidly rise in demand.
The dissolving pulp can be used to produce viscose fiber instead of other fibers. The production process of chemical pulp for papermaking is similar to the counterpart of the dissolving pulp. Some papermaking enterprises alter production line of chemical pulp to that of the dissolving pulp, significantly enhancing the profitability. In the market it is commonly concerned.
The famous papermaking enterprises like that include as follows:
-
A. Qingshan Paper Co., Ltd.
Newly-built annual output of 120,000 tons of the dissolving pulp production line -
B. Yueyang Paper Co., Ltd.
Annual output of 400,000 tons of the dissolving pulp production line transformed from chemical pulp -
C. Sun Paper Co., Ltd.
Annual output of 170,000 tons of the dissolving pulp production line transformed from chemical pulp -
D. Chongqing Lee&Man Paper Mfg, Ltd.
Annual output of 150,000 tons of the dissolving pulp production line transformed from chemical pulp -
E. Sichuan Tianzhu Paper Co., Ltd.
Newly-built annual output of 120,000 tons of the dissolving pulp production line -
F. Anhui Huatai Paper Co., Ltd.
The dissolving pulp production line transformed from chemical pulp
In textile industry, cotton substitutes are mainly synthetic fiber (polyester) and viscose fiber. Viscose fiber is similar to cotton in texture and has obvious advantages of comfort, permeability and other aspects compared with the former. So the viscose fiber becomes the inevitable choice to replace cotton in China. For three categories of textile raw materials, the application ratio of cotton, polyester and viscose is about 60:30:10. Currently main manufacturers are improving the application amount of viscose, so the ratio reaches 50:30:20. This inevitably stimulates rapid growth in demand for viscose fiber. Main raw materials for the production of viscose fiber are cotton linter pulp and dissolving wood pulp. In recent years, due to a reduction in the cotton planted area, the dissolving wood pulp has become main source of raw material of viscose fiber. Now the concept of the dissolving pulp mostly refers to the dissolving wood pulp. Seen from the analysis of final products, viscose fiber accounted for 63%, acetate fiber 16%, ethers 14%, nitrate 4%, and other 3%.
The dissolving pulp is basically similar to papermaking pulp on appearance, but there is a big difference between use and quality standards. The enterprises belong to the category of papermaking industry abroad. But according to China's industrial categories, the dissolving pulp belongs to the textile industry. Why? The dissolving pulp is raw material of recycled cellulose fibers in textile industry.
The dissolving pulp must be with the feature of higher content of alpha cellulose, good solubility and low impurity content. The dissolving pulp can be gotten by modifying sulfate and sulfite. Its purpose is to get high polymerization of pure cellulose but lignin and hemi-cellulose are removed as the impurities.
Dissolving Pulp Raw Materials Features
Main raw materials of the dissolving pulp are wood, short cotton linters and so on. The raw materials shall be with the following features:
- High α-cellulose content;
- Less ash and resin content;
- Single cell and less complex cells;
- Easy bleaching and waste recycling;
- Easy processing and less rot of raw material;
- Large amount of raw materials or easy reforestation.
Wood is main raw material for the dissolving pulp, including softwood and hardwood. The former includes hemlock, spruce, fir, pine and Yunnan spruces, pines, etc. The softwood is taken as raw material for the dissolving pulp production all over the world. With the consumption growth of the dissolving pulp and the improvement of the pulping technology, hardwood is also widely used into the production. At present, pre-hydrolysis kraft pulp can adopt 80 kinds of hard woods while sulfite pulping can adopt 40 kinds of hard woods.
The dissolving pulp belongs to high purity of refined pulp, which is mainly used for the production of viscose rayon, nitrocellulose, cellulose acetate, glass paper and other products. Main raw materials are short cotton linters and wood. Because of the instable factors cotton linter in price and supply, the cotton linter pulp has been replaced by wood pulp gradually. Compared with the cotton linter pulp, wood pulp has better and uniform viscose processing performance, especially strong viscose filtration. Now non-wood materials are used for the preparation of the dissolving pulp, which has also attracted widespread attention, for example, bamboo.
Different from paper pulp, the dissolving pulp is not required in aspects of strength and morphology of the fibers. But for its aggregation degree and chemical composition, especiallyα-cellulose content and whiteness, it has higher requirements. According to the levels of the dissolving pulp, it can be divided by α-cellulose content. As α-cellulose content is less than 90%, it belongs to lower dissolution pulp; as between 90%-95%, it belongs to intermediate pulp; as more than 95%, it belongs to senior pulp.
China is the world's largest producer of viscose fiber. In the next few years, the viscose fiber production is expected to continue to maintain a growth rate of around 10%, which will make the demands of the dissolving pulp greatly increase.
Anyang machinery Co., LTD. is professional paper pulping production manufacturer in China. We are committed to dissolving pulp equipment development and production.
In the world, the dissolved pulp is mainly manufactured in the countries distributed in North America, South Africa, Brazil and other areas with rich forest resources. Due to continuous reforms of production technology and equipments, people seeks to further improve the performance of fiber production and gradually solve the problems of environmental protection. From the long-term development perspective, the living conditions of the dissolving pulp lie in eliminating the pollution of the environment in the production process. This requires the introduction and digestion of advanced technologies, the reduction of the pollution, improvement of the performance of fiber production process and continuous development of innovative products, which will become main development direction of the dissolving pulp.
