Search

Foam-assisted web forming and chemical application technologies have great potential to improve manufacturing efficiency and product quality in the paper and nonwovens industries. In this study, the benefits of foam forming and foam-assisted application of chemicals were demonstrated in a pilot machine trial. Uniform high-bulk webs of unrefined bleached softwood kraft pulp (BSKP) and viscose fibers were manufactured by foam forming. It was shown that foam formed low-grammage and high-bulk viscose fiber webs can be strengthened by foam-assisted application of latex onto the wet web. Correspondingly, foam-assisted application of carboxymethyl cellulose (CMC) and anionic polyacrylamide (A-PAM) improved the strength of the foam formed low-grammage and high-bulk BSKP web. Overall, the pilot machine results indicated that material cost savings could be achieved and a high-performance product could be manufactured with foam-based technologies.

This work focuses on analysis of optical transmittance images, which are captured at the end of the wire section of a pilot paper machine. The first priority is to evaluate the capability to estimate formation and floc size on the basis of optical transmittance and secondly analyse how process conditions affect them. Basis weight is one of the most important quality parameters in paper manufacturing. Optical transmittance seems to provide information about basis weight. Reliable evaluation of basis weight on the basis of image data would probably mean a new level of CD and MD profile controls. Formation means small-scale basis weight variation. Good formation e.g. improves the tensile strength and printability of produced paper. Camera unit located above and light source under the paper web at the end of the wire section to capture transmittance images, which were used to calculate several image features. Process and laboratory data were combined with image features for data based analysis. An increase in the basis weight, ash content and the dryness of the paper web seem to reduce the value of optical transmittance. On-line measured image features of optical transmittance were rather congruent with off-line defined reference values, especially the illumination corrected standard deviation of optical transmittance, which is connected to paper formation. Increased flow of headbox and lower consistency of pulp seemed to cause better formation as fewer flocs are formed. However, on the basis of analysis it is difficult to determine process conditions which provide with good formation and small floc size, because of the numerous interactions of process variables, the basis weight varied during experiments and it was difficult to keep other variables except the studied one constant.

The market for nonwovens increases every year due to improvement of machinery and equipment and functional properties of final products. The article describes production of nonwovens which include web forming, web bonding and web finishing. Web finishing has beside chemical structure of consistent fibres the biggest impact on functional properties of nonwovens. Here we present some of the most important web finishing and some new prospects for nonwovens surface modifications. Improved technology and new fibre modifications results in expanding nonwovens market on new area such as fashion garment.