Satoshi Fukuta

Development of Low-Density Wooden Molding Mat Using Bicomponent Fibers

We attempted to use wood shavings in their raw curled flake form as a base material in a mat to be used primarily as a heat-insulating/acoustic material in houses. The molding succeeded in producin...

Manufacture of compressed wood fixed by phenolic resin impregnation through drilled holes

An aqueous solution of phenolic resin was impregnated through drilled holes in wood, and we manufactured compressed wood with the deformation fixed by the phenolic resin. The methods of impregnation used in this study were an in-liquid platen-pressing method and a vacuum treatment. The effect of the drilled holes on solution retention was examined. Moreover, the control of solution retention was examined under the application of compression drying. The impregnation of resin into the specimens without drilled holes was insufficient, and the deformation could not be fixed. On the other hand, sufficient impregnation was possible in the specimen with drilled holes, and the deformation fixation was observed. At the stage of compression when the solution was squeezed out of the specimen, the solution retention of each specimen was accurately controlled in the specimens with drilled holes. At the stage of compressive deformation and deformation fixation using a hot press, the specimens without drilled holes could not be processed normally because swelling occurred. However, swelling did not occur in the specimens with drilled holes.

Evaluation and fireproofing treatment of wooden heat-insulating/acoustic absorbing materials

Heat insulating and acoustic absorbing materials were endued with fireproof performance and subjected to quantitative evaluations assuming a variety of uses and situations. Fireproofing was performed by spraying an aqueous solution of flame retardants on raw materials (wood shavings, kenaf bast fibers, and core-sheath-type fibers) during the fiber spreading and mixing step. It was possible to treat the materials homogeneously and without increasing manufacturing workload. Flame retardancy was evaluated using vertical flame testing, horizontal flame testing, the 45° Meckel’s Burner method, and a cone calorimetry method in accordance with UL94, JIS D 1201, JIS L 1091, and JIS A 9521, respectively. It was possible to achieve results that satisfied each of these standards, along with quantifying the relations between treatment conditions and performance.

Sound absorption and form retention of newly developed heat-insulating/acoustic material

A wooden mat to be used as heat-insulating/acoustic material was developed using wood shavings in their raw curled flake form as the primary material. This report discusses the influences of fabrication conditions on sound absorption and form retention. The results showed that the form retention was increased with kenaf composition. However, the normal incidence absorption coefficient decreased with increasing kenaf composition and improved with increasing shavings composition. The increase of airflow resistivity was shown as the reason. Moreover, element’s internal loss of solid-borne sound transmission and the influences of various acoustic parameters that the shape of the element brought were considered as the reason. Sound absorption coefficient in a reverberation room was measured under optimum fabrication conditions, and the performance of the mat was found to be approximately equal to that of glass wool.ZusammenfassungEntwickelt wurde eine Holzmatte zur Verwendung als Wärme- und Schalldämmmaterial. Dafür wurden als Hauptmaterial natürlich gekrümmte Hobelspäne verwendet. In dieser Studie wird der Einfluss der Herstellungsbedingungen auf die Schallabsorption und Formbeständigkeit beschrieben. Die Ergebnisse zeigten, dass die Formbeständigkeit mit zunehmendem Anteil an Kenafbast zunahm. Jedoch nahm die Dämmwirkung mit zunehmendem Kenafanteil ab und mit zunehmendem Hobelspananteil zu. Als Grund dafür wurde die Zunahme des Luftstromwiderstandes festgestellt. Außerdem wurde die geringere Körperschallübertragung sowie von der Spanform abhängige Akustikparameter als Grund hierfür angesehen. Es wurde der Schallabsorptionsgrad in einem Hallraum unter optimalen Herstellungsbedingungen gemessen und es wurde gezeigt, dass die Eigenschaften der Matte mit denjenigen von Glaswolle vergleichbar sind.

Shear properties of metal-free wooden load-bearing walls using plywood jointed with a combination of adhesive tape and wood dowels

In this study, the potential of wood-only (metal-free) load-bearing walls was proposed and tested based on the idea of using the same type of material throughout wherever possible while improving basic properties such as strength, sound insulation, and heat insulation. Specifically, a technique was tested of combining pressure sensitive adhesive tape and wood dowels in place of nails for load-bearing structures with panel reinforcement represented by wood-frame construction. For this paper, its strength was evaluated by conducting in-plane shear tests, which revealed that the initial rigidity and maximum load of the proposed test specimens were greater than that of specimens using nails for jointing. However, the shear load factor, which is calculated based on some strength parameters and which forms the foundation of housing strength design, was slightly lower than that of the nail-jointed specimen. This was because there was a large decline in post-collapse resistance and a lower calculated absorbed energy caused by brittleness. The early detachment of panels was also revealed as a problem in the tests.

Thermal Conductivity and Volumetric Specific Heat of Low-Density Wooden Mats

Abstract Using wooden waste as insulation material benefits society by using waste products, reducing building thermal load, and sequestering carbon dioxide. In this study on heat insulating materials, a novel low-density wooden mat was fabricated from wood shavings and kenaf fibers. This research addressed the influences of fabrication conditions on the thermal conductivity and volumetric specific heat of the materials used. The raw materials (wood shavings and kenaf fibers) were mixed with a binder component, and the mixture was thermoformed. The thermal conductivity and volumetric specific heat of the mats were measured, and the influence of mixing ratio, density, and heat flux was evaluated. The results demonstrated that thermal conductivity was largely affected by the mat density and mixing ratio but was largely unaffected by changes in the heat flux. The volumetric specific heat of the mats was largely unaffected by the raw material mixing ratio but was greatly affected by the mat density. The tende...