Re-pulped paper is suitable for drawing paper, permanent document paper, filter papers, pads, file covers, duplicating papers, tissue papers, etc. The paper has high tensile bursting, tearing and double fold strength as compared to mill made paper and it does not turn to brittle due to aging. Re-pulped paper has good texture for drawing and writing.
Production of re-pulped paper involves these main steps;
- Preliminary Treatment
This stage requires cutting of the cotton rags into small bits with power operated rag choppers. In the case of agro fibers, the material, after chopping, is cooked in a small open digester with low percentage of alkali.
Next, the cut and dusted rags are beaten to pulp stock in small power operated Hollander beater, with or without bleaching. Then the material is washed by means of a washer drum followed by further beating. Addition of natural fillers /loadings and dyeing and sitting chemicals as required for the end product is also accomplished during beating.
- Sheet Formation, Peeling and Drying
Sheet formation is carried out by draining water from a dilute fiber mix through a fine screen and both dry the mat thus formed by dewatering with rollers. Then drying on heated rolls and smoothing with calendars is conducted. The calendared papers is hand sorted, edges trimmed with the help of power operated cutting machine and packed in suitable packets.
The alternative technology of producing re pulped paper is producing coated paper.
Coated paper has a thin layer of material such as china clay applied to one or both sides in order to create a surface more suitable for high-resolution halftone screens that have the highest optical density in the printed image. Coating requires additional machinery investment. Thus, this option is not recommended since the envisaged plant can sell its output to producers of tissue paper, pads etc .