Influence of Pressing Schedule and Adhesive Content on the Rheological Behavior of Wood Fiber-Furnish Mats

Abstract

In this study, for a better understanding of the hot-pressing process, the influence of adhesive content (AC) on various features of a typical pressing schedule for medium-density fiberboard (MDF) production, including fiber mat compressibility, heat transfer during hot-pressing, density profile and board properties, were evaluated. It was found that increasing the AC (urea formaldehyde) leads to faster heat transfer towards the mat’s central plane, mainly due to higher heat release from the adhesive polycondensation reaction. Moreover, the results indicate that the time needed to reach the critical mark of 100 °C in the central plane of the mat depends on the duration of the first densification level (FD). Importantly, the pressure peaks (pmax and p2nd) needed for mat densification are significantly reduced when increasing the AC, which might be attributed to the slippery effect created by the adhesive on the fiber surfaces. The duration of the FD also showed obvious effects on the intermediate density maxima (ρinter) and the core layer density (ρcore). In general, the physical and mechanical properties of MDF panels are significantly impacted by the pressing schedule and AC. All in all, the results of this study are valuable information for refining existing rheological models to improve their accuracy and their ability to simulate the vertical density profile during industrial production.

Development of Mineral-Bonded Plywood with Magnesium Oxychloride as a Binder Using the Hot-Pressing Process

“…However, TS was significantly reduced by increasing the molar ratio of W/C from 15 to 21. Thickness swelling in wood and EWP is a complex property influenced by several factors such as wood species, density, adhesive formulation, the stress relaxation of the board and other manufacturing parameters and their interaction [ 26 ]. In this context, the accessibility of water molecules to the OH groups of the wood has the greatest influence on the final TS value of the EWP [ 7 ].…”

“…However, most of the developed mineral binders and the corresponding EWP are still far from massive industrial implementation due to their cold-pressing technology. In the last 80 years, hot-pressing technology has dominated the field of EWP production because it allows massive and more economical production [ 26 ]. Actually, hot-pressing technology is the most critical step of the whole board manufacturing, as the properties of the final product strongly depend on the pressing conditions of the mat [ 26 ].…”

“…In the last 80 years, hot-pressing technology has dominated the field of EWP production because it allows massive and more economical production [ 26 ]. Actually, hot-pressing technology is the most critical step of the whole board manufacturing, as the properties of the final product strongly depend on the pressing conditions of the mat [ 26 ]. Initial approaches to the application of mineral binders (i.e., geopolymer) in EWP using hot-pressing technology similar to that of conventional EWP have been presented by researchers [ 13 , 15 ].…”

Utilization of coconut fiber waste as a filling material for list profile

“…Before the development of mineral plaster board technology in Indonesia, the list profile was made of solid wood carved with a propylene machine. One of the uses of coconut fiber waste is as raw material for the handicraft industry such as making list profiles [4][5] [6].…”