Date of Award
Bachelor of Science
Paper Science and Engineering
Vacuum formed products, commonly called molded pulp, are a superb alternative to expanded polystyrene (Styrofoam) in many current packaging applications. This movement from the petroleum based products of the past to innovative new wood fiber based packaging is due to many reasons including economic benefit, environmental stigma, and/or legislative intervention. The current dilemma is dealing with the inherent fiber characteristics, contaminants, and product composition of molded pulp products. As more of these products appear in secondary waste streams, there is a need for information pertaining these parameters. Unfortunately, very little technical information is available due to the high level of competition in this field.
Therefore, this project attempted to provide some of this background data by comparing several different samples of molded pulp to standard control samples of Occ, ONP, and a forty two pound virgin kraft liner. The samples were analyzed on the basis of fiber length distribution, freeness, fines content, reject rate, repulpability, and recyclability. Results showed extensive variation, especially in the area of freeness and contaminants. Freeness data ranged from 300 ml to 710 ml depending on the sample type, while contaminants included ink particles, dirt, plastics, shives, stickies, and wax.
Based on this project it seems as though a wide variety of raw materials are used to produce vacuum formed products. Therefore, careful screening to ensure proper handling of these materials is advised.
Molded pulp is an excellent low cost fiber source for specific applications where this high level of variation can be tolerate. Recycling results showed that both surface and strength properties of each sample performed within or near the results of the two control samples.
In summary, molded pulp provides an environmentally friendly alternative to the plastic based packaging of the past. The results from this report show that these fibers could fit very well into certain papermaking processes. There are many additional areas of research available in this field which will become more apparent as growth continues. If the movement from EPS to molded pulp continues, it will be necessary to devote more research as a larger portion of this fiber stream needs to be recycled.
Miles, Robert J., "The Recycling of Vacuum Formed Products and the Effect on Use Characteristics" (1998). Paper Engineering Senior Theses. 295.