音響喇叭箱用粒片板之研製（二）膠合劑混合比與佈膠率對振動特性之影響

Manufacturing of Particleboards for Acoustic Cabinets (II) Effects of Adhesive Mixed Ratio and Resin Content on Vibrational Properties of the Particleboard

黃國雄(Gwo-Shyong Hwang) ； 黃彥三(Yan-San Huang) ； 張上鎮(Shang-Tzen Chang)

《林產工業》 10卷3期 (1991/09) Pp. 71-79

摘要

本研究計劃第一報中已述及優良的喇叭箱用粒片板，須有較高之衰減特性，即有較大之對數衰減率及損失彈性係數，並由第一報之試驗結果得知，以50 % EVA膠與50 % UF膠混合使用製造粒片板，可獲得較高之衰減特性，此為正面結果，但另一方面使得粒片板之強度性質降低，此為負面效果，同時就製造成本而言，EVA膠之價格為UF膠之數倍，因此在實用上對EVA膠與UF膠之適當混合比，應更進一步加以探討，以期能夠發揮正面效果且能將負面效果減至最小程度。本報中所使用其有塑性性質之膠合劑為EVA膠與PV Ac膠，兩膠合劑在各種混合比下與UF膠混合使用，佈膠率設定為10%，製造6 mm厚之單層均質粒片板，另外在混合比為20%時，以不同之佈膠率製造粒片板，粒片板之測試包括強度性質與振動性質。試驗結果歸納如下：（1）EVA、PV Ac兩膠合劑分別與UF膠混合使用，在混合比30%以下時，兩者之強度性質受混合比之影響不明顯，但混合比為50%時，兩者之強度性質則明顯降低，且PV Ac膠降低之幅度較EVA膠大。（2）EVA、PV Ac兩膠合劑分別與UF膠混合比為20%時，強度性質體佈膠率之降低而明顯降低。（3）使用EVA膠時，其對數衰減率隨混合比之增加而顯著增加，使用PV Ac膠時，其對數衰減率隨混合比增加之效果較EVA膠者為差。（4）EVA、PV Ac兩膠合劑分別與UF膠混合比為20 %時，對數衰減率隨佈膠率之降低而有增大之現象，而損失彈性係數則相反。

關鍵字

粒片板 ； 對數衰減率 ； 損失彈性係數 ； 音速

並列摘要

In the previous paper, it was demonstrated that by using the combination of 50% ethylene-vinylacetate and 50% urea fomaldehyde as adhesives for making particleboard the damping property of the particleboard was effectively increased whereas the strength properties decreased. Therefore, the objective of this study was to investigate the effects of resin ratio on the vibrational and the strength properties of the particleboard and expectably to find an appropriate resin ratio for making speaker-cabinet-used particleboard. The plastic resin used in this study included ethylene-vinylacetate and polyvinyl acetate. The experimental results obtained were summarized as follows: 1. When the relative ratio of ethylene-vinylacetate or polyvinyl acetate to urea formaldehyde was below 30%, the effect of resin ratio on the strength properties of the particleboard was not significant. However, when the relative ratio was 50%, the strength properties of the particleboard decreased and the extent of decreasing was more significant for polyvinyl acetate. 2. When the relative ratio of ethylene-vinylacetate or polyvinyl acetate to urea formaldehyde was 20%, the strength properties and the loss modulus of the particleboard decreased significantly with decreasing the adhesive content whereas the logarithmic decrement of the particleboard increased with decreasing the adhesive content. 3. The logarithmic decrement of the particleboard increased significantly with increasing the ratio of ethylene-vinylacetate, but the increasing effectiveness of the logarithmic decrement for polyvinyl acetate is less than ethylene-vinylacetate.

並列關鍵字

Particleboard ； Logarithmic decrement ； Loss modulus ； Sound speed