Environmentally friendly production of reinforcing fibers for waste paper packaging papers

Lead Institute HF Institute of Wood Research

Development of an environmentally friendly process for a reinforcing fiber for waste paper packaging papers.

The decline in consumption and production of graphic papers has the consequence that the influx of high-quality fiber material into waste paper recycling declined.With a suitable process, high quality but low-cost primary fibers could be recovered for the reinforcement of waste paper.

Background and Objective

The aim of the project is the development of a straw-based pulping process for the production of high-yield pulp, which can be used to improve the strength properties of recycled paper-based packaging materials.

Approach

The research project will investigate two environmentally friendly pulping processes for straw.In the carbonate digestion, an inexpensive, very environmentally friendly chemical is used with sodium carbonate;the steam refining process can ideally be applied without chemicals.Both methods and method combinations are tested and adapted for the application.

Results

The investigations showed that high-yield pulps with good mechanical properties can be produced with mild chemical pulping using sodium carbonate. With completely chemical-free steam pulping, however, it is difficult to produce pulps with strengths that exceed those of waste paper.

In principle, higher strengths could be achieved with more severe pulping (higher temperature and use of chemicals), but at the cost of a lower yield. In a comparison of the different pulping methods, sodium carbonate pulping led to a better ratio of yield to strength compared to steam refining treatments. Very high strengths of the pure straw papers did not lead to correspondingly higher strength increases in blending tests with waste paper. The conclusion is therefore that milder pulping processes with higher yields should be preferred for the production of strength-increasing pulps.

Further details on the results of the vapor pressure pulping can be found in a publication published in March 2024.