Influence of Fiber Types on Fiberweb Properties in High-Speed Carding

Abstract

Among all nonwoven manufacturing techniques, carding presents high flexibility in different aspects. Being regarded as the conventional way of web forming, this method is trying to meet today's high production needs. Therefore, the productivity of the nonwoven card is more critical then ever. The fact that some fibers cannot be processed at higher speeds as others in carding is one of the biggest drawbacks of the system that needs to be resolved.

It is the main objective of this research to investigate the role of fiber type on nonwoven carding productivity and quality. In order to realize this goal, a totally novel approach have been designed and implemented through the course of this research.

A set of fibers was designed to be used in the experiments. The most important feature of these fibers is their fixed diameters. Namely, all experimental fibers have the same diameter. The main idea behind fixing the fiber diameter is that it allows us to card different fiber types under unchanging conditions. In other words, it eliminates all the possible effects, but the fiber type, on the performance of the card. Another interesting aspect of the experimental fibers is the design of bicomponent fibers, which have a core/sheath structure with minimized sheath thickness. The intention was to create a fiber with the sheath as a skin over the core. PET and PP polymers were chosen.

To eliminate all the factors, the entire card processing parameters was fixed. In addition, all fiber parameters, i.e. crimp, length, finish was kept constant to leave the effect of fiber type alone. A set of experiments was designed with two carding speeds, 85 and 120 m/min. Each fiber was run through the card at both speeds and planned samples were taken for data collection. Samples have been tested to obtain data of an array of fiber parameters, such as strength, modulus, fineness, and crimp stability; web parameters, for instance uniformity, fiber orientation distribution function, thickness and basis weight and feed matt openness.

The collected data was statistically analyzed to reveal the similarities and/or differences among the measured parameters. ANOVA tests were utilized to compare the means of data sets. Comparisons have been made among all experimental fibers to observe the effect of fiber type on the output, fiber parameters and carding performance. Mutual comparisons have been carried out between the bicomponent and monopolymer fibers. The aim of these comparisons was to disclose the role of fiber surface properties on its carding performance. Finally, conclusions and recommendations for future application have been covered.