Manufacturing and properties of ultra-low density fiberboards with an unsaturated polyester resin by a dry process

Abstract

Although ultra-low density fiberboards (ULDFs) have good sound and thermal insulation performance, formaldehyde emission in the manufacturing process and in the subsequent use of the products limits their field of application. The objective of this study was to employ an unsaturated polyester resin (UPR) in the manufacturing of the boards as a substitute of formaldehyde-based adhesives in order to develop environment-friendly ULDFs. The effects of UPR dosage, fiber treatment agent, press time and fiber consumption on the properties of fiberboards were studied. Sound absorption and thermal conductivity were also measured to ensure sound and thermal insulation properties of the fiberboards. Board density, modulus of rupture and thickness swelling in 2 h were 320 kg/m³, 4.14 MPa and 3.75%, respectively, under optimal conditions such as 12% UPR dosage, 1% fiber treatment agent, 400 g fiber consumption and 210 s press time. Noise reduction coefficient and thermal conductivity of the boards were found within a range of 0.68–0.58 and 0.038–0.048 W/(m K), respectively, while the density of boards ranged from 150 to 400 kg/m³. Therefore, sound absorption property of the fiberboards developed in this study satisfies the requirement of high-efficiency sound absorption materials, which is close to the value (0.67) of ULDF having a density of 56.3 kg/m³ obtained by a wet process. Thermal insulation property of boards was close to that of commonly used insulation materials such as rock wool [0.036 W/(m K)] and glass fiber [0.045 W/(m K)]. In conclusion, fiberboards can be used for non-structural furniture materials, sound and thermal insulation materials in buildings because of their environmental friendliness, good mechanical properties, and excellent sound and thermal insulation properties.