Research On The Sound Absorption Properties Of Cork Agglomerates Materials

In recent years, cork industry in China has achieved rapid development, thus develophigh value-added cork product in our country has become a crucial war of the cork industry.Especially since the21st century, low carbon, environmental friendly materials of interiordecoration also has become consumer’s first choice. Therefore, the development of the mutefunction of cork adornment material and compound floor materials made great contribution toour country’s national economic construction. This paper determined the absorptioncoefficient of cork agglomerates materials and its composite materials through standing wavetube method, analyzed the absorption coefficient influence factors such as material thicknessand density, base material type, composite structure and back empty cavity thickness. Theorthogonal experiment was designed that cork and wooden composite materials in which hasthe best sound absorption effect of the parameters combination and the performance of theorder. And compared the different thickness of the oriented structural straw board (OSSB),cork agglomerates materials’ sound absorption performance. This research provided theorybasis and development of the materials for cork. The results show that,1. Cork belongs to the porous absorption material, and it shows the typical porousmaterials absorption characteristics. The sound absorption coefficient increased withincreasing frequency, and the curve grew of ups and downs, and in the high-frequency soundwaves the absorption coefficient has superior performance than low-frequency sound waves.In the high frequency area, especially after the peak, the absorption coefficient curveamplitude gradually grew slowly with the increase of voice frequency, and finally morestable.2. The thickness and density of materials, composite structure greatly produced certaineffect of the sound absorption coefficient of the material. The thickness of materials grewdirect proportion to the absorption coefficient, and density grew inverse proportion to theabsorption coefficient. Cork materials on the surface area had superior absorption effect thancork in the bottom. With the same density and close thickness, cork veneering density boardcomposite had better absorption effect than pure wood blockboard. Therefore, in actualproduction, properly increasing cork material thickness, reduced density under certainstrength, or veneering cork layer on the surface wooden material can improve the function of the absorption effect.3. In the cork coalescence materials and wood base material composite structure, overall,cork cover on the surface area had superior absorption effect than cork in the bottom. Corkwith lower density, higher thickness of the larger, and with wood blockboard as base materialand larger cavity leave behind brought better absorption effect to composite structure. Thebest combination of factors are wood blockboard base material, cork density which was0.2g/cm~3, cavity thickness were100mm. Wood blockboard as base material of compoundstructure produced the best sound absorption. In actual decoration engineering construction,reducing the cork density, increasing the back cavity thickness can also improve the soundabsorption effect of composite structure.4. Cork agglomerates materials and overlaying OSSB composite structure process showsthat, cork cover can improve the OSSB sound absorption effect, overcome OSSB easilyabsorbing moisture and rough surface. Cork covering of the OSSB can be used asarchitectural decoration and furniture material. With isocyanate as adhesive, with Corkcovering OSSB, its better process parameters for: unit pressure1.1MPa, pressing temperature110℃, pressing time for3min, glue of80g/m2. Cork covering OSSB performance meet theGB/T15104-2006.5. OSSB without covering had poorer sound absorption effect, for9mm thickness,12mm,17mm of OSSB average absorption coefficient were less than0.2;14mm cork coveredOSSB absorption performance is better than not covering. In500~4000Hz frequency range,the average absorption coefficient is0.202, the absorption effect covered material is superior,cork cover can effectively enhance OSSB absorption effect, belongs to the nice soundabsorption ability material.6. Veneer covering or cork rubber covering OSSB are not nice sound absorptionmaterials. But cork rubber cover OSSB the absorption coefficient around2000Hz reached0.2above, it showed that cork rubber cover can enhance the sound absorption function, but not aseffectively as cork. In the future research or manufacturing can be improved through the corkrubber production process, cork plays absorption effect, reduce raw material cost, and get thegood anti-seismic wear-resisting performance, cork rubber materials can be used as thesubstitution of the veneer decorated indoors to get better sound absorption effect.