Third, the key technologies for the production and recycling of paper products and the realization of recycling
3.1 Technology to Solve Pulp and Paper Pollution
Chlorine-free or chlorine-reducing bleached pulp New technology Chlorine-free bleaching (TCF), also known as non-polluting bleaching, is the use of non-chlorinated substances such as O2H2O2, O3, etc. as bleaching agents for pulp bleaching in medium to high concentrations; Bleaching (ECF) uses CLO2 as a bleaching agent to bleach paper pulp at medium concentrations. Chlorine-free and low-chlorine bleaching are intended to replace chlorination bleaching and hypochlorite bleaching of low-consistency pulps, which are environmentally polluted.
(1) Oxygen bleaching Since oxygen is non-toxic and does not pollute the environment itself, after the oxygen delignification process, the amount of bleaching agent and bleaching wastewater in the latter stage can be reduced by 50%. It has been proved that oxygen bleaching can greatly reduce the BOD in bleaching wastewater. The COD, chroma, and total organochlorine content play an important role in reducing the pollution of modern pulp bleaching wastewater.
(2) Hydrogen peroxide bleaching Hydrogen peroxide is often used in the post-stage of multi-stage bleaching of chemical pulp to improve the whiteness of the pulp and the stability of the whiteness of the pulp after bleaching, in addition to the bleaching of mechanical pulp.
(3) Chlorine dioxide Bleaching Chlorine dioxide is a free radical in itself, with excellent bleaching performance, strong bleaching ability, high efficiency, and whiteness stability. The most important feature of chlorine dioxide bleaching is the selective removal of lignin during bleaching. The degradation of carbohydrates is small and the strength of the pulp is good. Therefore, chlorine dioxide is still playing an important role in pulp bleaching.
(4) Ozone bleaching Ozone has strong delignification and bleaching effects. In the pulp bleaching system, it can be used alone. It can also be used in combination with hydrogen peroxide, oxygen, and other bleaches to form multi-stage bleaching. The greatest attraction of ozone bleaching is achieved. The environment is non-pollution. For example, the chlorine-free bleaching process O-Z-E-P bleaches the pulp. It is ideal for any pulp and paper mill, and the concentration of the ozone bleaching stage also has a medium and high concentration. Divided, namely medium-density ozone bleaching and high-concentration ozone bleaching.
3.2 Waste Paper Recycling Technology
The two key technologies for waste paper recycling are the removal of impurities and deinking, and the recovery of the waste paper's complex copying ability.
Waste paper pulp and paper can reduce pollution, but waste paper is still more serious in the deinking process. In general, the ink is removed, first by chemical dissolution, and then by mechanical washing to remove the ink from the pulp. If regeneration of the white pulp is required, bleaching and rinsing should also be included.
In order to prevent waste paper circulation from decreasing the paper strength, it is necessary to improve the recovery of the waste paper recopying adaptability. Generally, some fine fibers are removed or paper enhancers, filter aids, retention aids and the like are used, and a polymer reinforcing agent may also be used to bond fibers instead of hydrogen chain bonds between fibers to increase paper strength.
Fourth, the conclusion
Based on the characteristics of paper products packaging, how to make a green package has made a shallow analysis and the key technologies needed to solve this problem. From the actual production process of green packaging paper products, implementing green packaging in the packaging industry can not only promote the development of China's green packaging, but also promote the protection of human ecological environment, participate in the global "green revolution", break the green trade barriers, Promoting the negative aspects such as the sustainable development of China's economy is of far-reaching significance.
Source: Wang Lei, Department of Art and Design, Henan University of Science and Technology