Abstract
The wet-laid web formation technique in which fibers dispersed in water are deposited on a screen and dewatered has been widely used in obtaining unifomly distributed fibrous assemblies. Compared with a dry-laid web, the distinctive feature in a wet-laid web is the isotropic nature and this is widely utilized in industrial application. A new wet-laid web forming machine was designed and built to produce nonwovens of high tenacity fibers such as carbon, glass, and oxidized carbon fibers, and the uniformities of the webs were characterized. The parameters considered were bonding pressure, aspect ratio, and fiber in type. The web uniformity was significantly affected by the state of dispersion of the fiber water. In the case of $Oxipan^ⓚ$ nonwoven, the uniformity increased as bonding pressure and time increased. Similar trend was observed as aspect ratio increased. Especially, the best uniformity could be obtained at aspect ratio 750 in $Oxipan^ⓚ$ nonwovens while the best uniformities were at the aspect ratio 1200 in carbon nonwovens and 450 in glass nonwovens. As fiber content increased, th uniformity in $Oxipan^ⓝ$ nonwovens improved continuously, while in carbon and glass nonwovens, significant improvement in uniformity started to appear only over the fiber content of 50%.
