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ABSTRACT
This study examined the properties of composites made from secondary fibers from old corrugated containers (OCC). A polyisocyanate resin was used to consolidate the OCC fiber composites with a dry manufacturing process. The properties of the OCC fiber composites were compared to the properties of fiber composites made from virgin aspen that were thermal-mechanically pulped (TMP). Generally, all OCC fiber composite properties were determined to be inferior to those of virgin aspen TMP fibers. A literature review is also presented that provides possible causes for the inferior quality of OCC fiber composites.
Wastepaper is often remanufactured into paper and paper products. Most of theses products are destined for short service life applications, which subjects the secondary fibers to repeated recycling operations. Wastepaper recycling results in the loss of fiber, paper (10), and paperboard strengths (15), and influences papermaking and product conversion operations (15). In contrast, most wood fiber composites, such as hardboard, medium density fiberboard, and insulation board are used in long-term applications. Manufacturing secondary fibers into composites for long-term applications could provide an alternative to traditional wastepaper reuse technologies. This would reduce the need for repeated recycling of secondary fibers.
Newsprint primarily consists of mechanical and thermal mechanical pulp (TMP). TMP is also used for manufacturing many fiberboards. Old newsprint (ONP) has been studied as a raw material for making fiberboards (18,30) and other fiber-based composites (25). Mechanical and water resistance properties of the dry-process hardboards were reported to deteriorate progressively as the quantity of ONP increased (18).
Old corrugated containers (OCC) are made of linerboard and corrugated medium, which predominantly consists of the kraft pulp of softwoods and neutral sulfite semichemical (NSSC) pulp of hardwoods, respectively. However, linerboard may contain up to 20 percent hardwood and other secondary fibers, and modified kraft and soda-pulped fibers are also used in manufacturing corrugated medium (14). An industrial production trial reported that the properties of wetprocess hardboard containing 20 percent OCC fibers were comparable to conventional (no OCC) hardboard when stock freeness was properly controlled (17).
This paper presents flexural strength and water-related properties of dry-process polyisocyanate resin consolidated OCC secondary fiber composites. Properties of virgin aspen TMP fiber composites from our previous study (31,32) are also presented for comparison. There are experimental aspects...