Yarn-drying

Yarn drying procedures are far more critical than staple drying procedures. AH ceUulosic fibers expand when wetted and contract on drying, the... 

In the manufacture of fast cord the first process is to coat paper or textile yarns with a blackpowder/nitrocellulose dope by a dipping process. These yarns are thoroughly dried and a number of them passed through an extruder and given a thick covering of plastic incendiary composition. The cord thus produced is covered with a protective layer of plastic, usually polyethylene. The overall diameter of the cord is about 2-5 mm. 

Type of rayon Dry yarn strength g. per denier Elongation, percent Accessibility, percent... 

Material tested Accessibility percent Reactivity0 Yarn strength g. per denier, dry Yarn elongation percent, dry... 

Acrylic fibers generally have good hand, as its called in the business (they re soft). They resist creasing, and they are quick to dry. Acrylics have replaced wool in many applications, such as blankets and sweaters. Because of their unique bulking characteristics, they take on the appearance of wool yarn. 

Research effort at Albany International Research Co. has developed unit processes necessary for pilot scale production of several species of reverse osmosis hollow fiber composite membranes. These processes include spin-dope preparation, a proprietary apparatus for dry-jet wet-spinning of microporous polysul-fone hollow fibers, coating of these fibers with a variety of permselective materials, bundle winding using multifilament yarns and module assembly. Modules of the membrane identified as Quantro II are in field trial against brackish and seawater feeds. Brackish water rejections of 94+% at a flux of 5-7 gfd at 400 psi have been measured. Seawater rejections of 99+% at 1-2 gfd at 1000 psi have been measured. Membrane use requires sealing of some portion of the fiber bundle for installation in a pressure shell. Much effort has been devoted to identification of potting materials which exhibit satisfactory adhesion to the fiber while... 

Rayon was first made by denitration of cellulose fibers (Chardonnet process). The cellulose was first reacted with a mixt of nitric and sulfuric acids to form NC, The prod was then dissolved in a mixt of eth and ethanol and spun into yarn by a "dry spinning process. In some instances the yarn was denitrated by alkaline hydrosulfites, neutralized and then w washed and dried (Ref 9). See also under "Cellulose Nitration, Denitration in Vol 2, C118-R to C119-R... 

When nylon is made in industry, it forms as a solid which is melted and forced through small holes (Figure 15.19). The long filaments cool and solid nylon fibres are produced which are stretched to align the polymer molecules and then dried. The resulting yarn can be woven into fabric to make shirts, ties, sheets and parachutes or turned into ropes or racket strings for tennis and badminton rackets. The annual worldwide production of nylon is expected to reach 6 million tonnes by 2015. 

An important condition to be fulfilled in order to use the method for detection of sweat formation and its composition is that the electrodes are elec-trolytically in contact with each other. This is not a strict condition for urine detection and as an early-warning system for diabetes, because in these applications a qualitative detection is enough, and therefore one can start with dry electrodes. For diagnosis of cystic fibrosis, this is not possible because here a quantitative detection of salt concentration is expected. Therefore, one needs to start from a system with electrodes that are elec-trolytically in contact with each other right from the start of the experiment. For this purpose, water is immobilised in high-density cotton in which the conductive stainless-steel yarn electrodes are implemented. 

The materials used included dyed and undyed yarn and fiber samples obtained from the manufacturers and fabric and other polymeric materials from the marketplace. The samples were encapsulated without preparation and the experimental conditions are noted on each figure. Unless otherwise noted, the DSC samples were run in an atmosphere of dry nitrogen. 

Natural materials can be found in many forms in museum collections. The items in this photograph include wool, cotton, wood, leather, dried plant materials, paints, and metal alloys. Rug/carpet kurdish mid-twentieth century wool on cotton, naturalpigments/dye. Basket Hopi piki-bread tray, wicker, early twentieth century. Kachina c. 1970 cottonwood root with water-based (poster) paint, fabric, wool, feathers, yarn, fur ruff, unsigned (cloth "cape is also painted). Books calfskin, marbled paper, gold. Baseball leather, linen cord, pen ink. Glove leather, metal (grommets). Gun wood, metal (brass, steel). 

Information in Table II describes the performance characteristics of typical seed cotton drying systems and Illustrates some of the effects of drying fibers to a level below the optimum. Generally, these data show that fibers ginned at moisture contents below 6 percent were shorter and produced lower yarn break factors than fibers ginned at moisture contents above 6%. Obviously, the amount of energy required for drying... 

Table II. Some Effects of Seed Cotton Drying on Fiber and Yarn Properties.3...

To determine the effect of the aging of degraded starch and the effect of drying temperature, a series of tests were run In which fermentation age was varied from 7 to 40 days and drying from 20 C to 100 C (Table III), The relatively small variations observed In the data Indicated that neither aging nor temperature produced any significant effect on yarn properties. 

Normally, the first step in textile conservation is the examination of the piece to determine the fibers from which it was made and the technique by which it was created. One determines the spin of the yarns, whether Z or S, and the number of wefts and warps per inch. Next, one tests for colorfastness first with distilled water, then with glycerin and water, and finally with a neutral detergent and water. If the colors run with any of these solutions, obviously the piece cannot be washed, and one tests with dry-cleaning solvents and other chemicals. 

The strength of acetate yarn upon exposure to dry heat (120°C) for 500 hr is reduced by 58%. That of triacetate yarn is reduced by 30% at 130 °C (68). In another publication (73) heat aging experiments indicate that the strength retention of triacetate is greater than cotton, which in turn is greater than nylon. Experimental details, however, are lacking in the aging conditions and the type and form of the fibers. 

Rhoplex K-3 was also applied in combination with 1.2% polyethylene (Moropol 700, supplied by Mortex Chemical Products), a material that lubricates the surfaces of the yarns, gives the fabric more flexibility, and increases the tearing strength of resin-treated wash and wear fabrics (4). A second sample of Rhoplex K-3 with 1.2% polyethylene added was air dried instead of oven dried to assess the influence of different drying methods. 

Fig. 12.9. Flow diagram for manufacture of cellulose acetate yarn (1) wood pulp (2) attrition mill (3) cyclone (4) 35% acetic acid (5) pretreater (6) magnesium acetate solution (7) precooled acetylation mix (8) sulfuric acid (9) acetylator (10) ripener (11) steam (12) blender (13) precipitator (14) dilute acetic acid (15) hammer mill (16) water (17) rotary screen washer (18) squeeze rolls (19) drying oven (20) blender (21) storage bins (22) silos (23) weight bins (24) acetone (25) wood pulp (26) pigment (27) mixers (28) hold tanks (29) filter press (30) pump (31) filter (32) air (33) jet (34) acetone recovery (35) oiling wheel (36) feed roll (37) bobbin (38) inspection.

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