Thomas Stegmaier of the Institut für Textil- und Verfahrenstechnik (ITV), Denkendorf (Germany) described a 3-layer textile roofing fabric engineered to allow air to be pumped through the middle layer. This air reached 150-160oC on a hot day and was used to dry out a silica-gel “energy store”. This stores the energy “without loss” and yields warm dry air months later when humid air is pumped through it.
Asked about the efficiency of heat recovery, Mr Stegamaier said this had yet to be calculated.
Frank Hermanutz of the Institut für Textilchemie und Chemiefasern (ITCF) Denkendorf, Denkendorf (Germany) has used spinnerets made by new laser hole drilling technology for the direct spinning of cellulose and cellulose acetate fibres. The holes are drilled with an ultra-short pulsed laser using a highly focussed beam circulating helically around the circumference of the required hole. The system was developed at IFSW in Stuttgart. The resulting holes have a naturally conical inlet and a precise outlet down to 25 microns in diameter. Half-inch thimbles with 2000x25 micron holes in gold/platinum looked excellent for wet spinning and for air-gap, a 250 hole stainless steel version had been made. Cellulose microfibers down to 0.2 dtex have been wet-spun from a solution of cotton linters in an ionic liquid (8% to 16% in 1-ethyl-3-methylimidazolium acetate) and from cellulose acetate in acetone. The latter had a very rough non-circular cross section.
Christoph Rieger of the Institut für Textil- und Verfahrenstechnik (ITV), Denkendorf (Germany) promoted ITV’s recently developed ability to produce melt blown PP down to 0.4 microns and stabilised melt blown PET webs of high strength and thermal stability to 200oC. They are also capable of hydroentangling melt blowns and their laminates with other fabrics to get the best combinations of strength and fineness.