Development of a One-Step Process for Production of Foam Core Particleboards using Rigid Polyurethane Foam
A simulated one-step process has been developed for the production of foam core particleboards using rigid polyurethane as the core layer. The results showed that the different techniques used for surface layer separation (unresinated particles and sprayed water) and foam injections (open system and closed system) had no influences on panels’ characteristics. Mechanical properties (e.g., bending strength and internal bond strength) were mostly influenced by the surface layer thickness, while the water absorption and edge screw withdrawal were influenced by the foam cell structure. The use of sprayed water for surface layer separation doubled the formaldehyde emission (FE) of the panels. The addition of urea (based on 10% of the dry resin) to the sprayed water had a positive effect of reducing the final FE. Furthermore, increasing the surface layer thickness had a positive, linear relationship with FE.
Effect of ingredient ratios of rigid polyurethane foam on foam core panels properties
One-step manufacturing process (in-situ foaming) provide great potential for the production of foam core panels. Polyurethane (PU) foam showed good applicability for use for in-situ foaming. Here, the effect of ingredient ratios of rigid PU foam on foam performance and panel properties is investigated. It was observed that the isocyanate (ISO) content and polyols (PO) type and content significantly change the foam and panel properties. Foam cell density, as the most important factor influencing the foam characteristics, was higher in foams with higher ISO and polyether content. Bending strength, internal bond and screw withdrawal resistance of the foam core panels were significantly enhanced when the ISO and polyether content was increased in the foam formulation. Varying the ISO content had no influence on panel properties with higher content of polyester (60%) in the PO blend. Varying the foam ingredient ratios did not change the thickness swelling, while the water absorption was dependent on the foam components ratios. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44722.
Water absorption of expanded polystyrene boards
Abstract The water absorption of expanded polystyrene boards was studied with the aim of developing a procedure for prediction of long-term absorption on the basis of short-term absorption data. The specifications of EN 12087 on test methods for determining long-term water absorption of expanded polystyrene by total immersion over a period of 28 days have been discussed and some disagreement between the specifications provided by EN 12087 and EN 13163 have been observed. The results obtained in determining water absorption of specimens of EPS boards with density ranging from 12 to 35 kg/m 3 , which were manufactured by various firms by foaming raw beads supplied by various manufacturers, are presented. The tests were performed in accordance with methods 2A and 2B (EN 12087). Based on regression equations presented in the paper, a comparison of the experimental results obtained after different periods of immersion was made. Interval prediction (for 15 yr) of the increase of long-term water absorption for EPS boards is described. A special coefficient K is used to correct for the expansion of the boundaries of confidence interval due to discounting of experimental information.