Weaving additives

In addition to aerospace uses, sihca fibers can be twisted into sewing threads and yams for weaving into fabrics. These fabrics are used extensively for heat-resistant clothing, flame curtains for furnace openings, thermocouple protection, and electrical insulation. The cloth can also be used to encapsulate other fibers to produce flexible sheets. 

Fabrics of Woven Fibers For cake filtratiou these fabrics are the most common type of medium. A wide variety of materials are available some popular examples are listed in Table 18-10, with ratings for chemical and temperature resistance. In addition to the mate-ri of the fibers, a number of construction characteristics describe the filter cloth (1) weave, (2) style number, (3) weight, (4) count, (5) ply, and (6) yarn number. Of the many types of weaves available, only four are extensively used as filter media plain (square) weave, twill, chain weave, and satin. 

Square-mesh cloth is the conventional type of screen cloth, but there are many types of cloth with an oblong weave. This latter construction provides greater open area and capacity and in addition makes it possible to use stronger wire for the same size of screen opening and for the same percentage of open area. 

As with tissue, woven glass cloth is used for decorative or acoustic purposes. Additionally, close-woven fabrics give improved fire-safety properties and are resistant to mechanical abuse. Glass cloth or scrim of an extremely open weave is used on insulants as a key for mastic or hard-setting finishes. 

Individual size polymers may be used alone or in combination with one another and their performance may be further improved by the addition of other components such as waxes and lubricants. However, whilst sizing offers many benefits in the subsequent weaving of the yarns, it is anathema as far as wet processing is concerned. A typical sized yarn may contain as much as 34% of impurities, distributed as shown in Figure 10.15. These impurities can interfere with wetting-out and with bleaching. They may also affect coloration processes. Depending on the type of size and the dyes used, dye uptake may be increased or resisted ... 

Addition of acrylamide to starch improved the performance of cotton yarn more than acrylamide alone, but addition of poly(vinyl alcohol) to starch lowered the performance of the yarn compared with poly(vinyl alcohol) alone. Overall, taking into account economic considerations, stringent pollution requirements and the needs of desizing, the singlecomponent hydroxyethyl starch showed optimum acceptability for weaving performance at moderate relative humidity. 

Weaving zone is spacious and can accommodate additional devices to automate the formation of interconnections/disconnections while weaving. 

Jorge Ibanez first conceived the idea for this book. Zvi Szafran (New England College, USA) induced us into making this a full textbook and not simply a laboratory manual. Margarita Hernandez was the architect and Jorge Ibanez the main driving force behind the project—they weaved the threads from the different chapters into an orderly whole. In addition, Carmen Doria endowed this book with her expertise... 

Water soluble ethoxylated size bath additive. Anstitatic softener/lubricant applicable from size baths. Improves both sizing and weaving. Being highly water soluble it is very easily removed from the fabric and is recommended in preference to other lubricants where there is a problem of removability of waxes. 

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