BODYING of FIBERS, YARNS AND FABRICS

BODYING of FIBERS, YARNS AND FABRICS

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Post 149  -by Gautam Shah 

Fibers, yarns and fabrics have poor bulk or lose the bulk during various treatments, are re-bodied by many different substances. Bodying is also possible without any substantive material application. Certain heat and water treatments shrink the materials, increasing the bulk, whereas mechanical (physical) manipulations also increase the apparent bulk.

Bodying is required to control the next process. Fibers (like silk) are bulked to aid re-spinning or handling before the end stage like stitching, packing and presentation or use of the material. Bodying has strong effect on the suppleness (fall of curtains, drapes, crease lines) and tactile feel of the material. It also affects the thermal management (through heat exchange and moisture movement). For curtains-drapery fabrics the bulking governs the diffusion of view across, ‘modelling’ of the objects, diffraction of light, masking and strength. For furnishing fabrics and floor spreads the bulk, suppleness, direction of texture, electrical behaviour, moisture absorption, dust and body scale retention, and micro air movements over the surface are important, and these are endowed by nature of such treatments.

 

Some of the prime techniques of bulking fibers, yarns and fabrics are manipulative in nature like: leave behind impurities, lints, staple fibers etc. by reduced carding, etc., mixing of different fibers before spinning, co-spinning (with coarser fibers), twisting, mixed fibre weaving (with mixed for warp-wefts), employing fabric formation techniques like weaving, knitting, shrinking, perma-crease setting, singeing etc.

Another method of bodying is to add some form of gum or size (simply starch), in the form of starch, gelatin, or resin or a combination of these with lubricating substances such as oils or wax. Some are temporary materials and are removed during laundering. Cheap cotton or rayon fabrics are often heavily starched for stiffness which after laundering may become quite limp. Fabrics like organdy are permanently stiffened cottons. The application of a carefully controlled acid solution causes the surface of the yarn to become softened and a gelatin like. An after wash in cold water causes the gelatinous outer surface to harden forming a permanently stiffened exterior.

Raw silk contains, from 25 to 30 percent of its weight in sericin or gum. And when the fiber is cleaned this substance is removed. Silks may be weighted both to enable the producer to regain some of the loss in fiber weight and to add greater body to fabrics. The silk fabric is first placed in an acid solution of stannic chloride (a chloride of tin). The fiber is allowed to absorb the substance, it is then washed, placed into a solution of sodium phosphate and then is washed again. During this process, an insoluble compound (tin phosphate) is formed within the fiber, and the weight and body of the fiber is increased. A further treatment with sodium silicate solution forms another chemical compound. The silk fiber can hold considerably more than its own weight of this added chemical weighting. Heavily weighted silks may have very poor abrasion resistance and eventually will break from their own weight. Any silk labelled pure dye Silk may not contain more than 10 percent of weighting, or 15 percent for black fabrics. If heavily weighted silks are burned, a skeleton of the metallic compound in the shape of the woven fabric is left behind.

Wool fabrics are fulled to give the fabric a more compact structure. In a type of pre-shrinking, fabrics are subjected to moisture, heat, soap, and pressure. This causes the yarn to shrink and to lie closer together and gives the fabric a denser structure. Wool cloth may be given more or less fulling, depending upon the desired characteristics of the resultant fabrics. Melton cloth, for example is one of the most heavily fulled wool fabrics and has a dense, felt like texture.

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SHEER FABRICS

Post 146 - by Gautam Shah

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Sheer is tactile feeling that is satisfying and delightful. It is a feeling or a state of experience. Sheer fabric is a very fine, gossamer or diaphanous material that does not occlude vision through it. It is an important quality mark for lightness of mass. The word sheer is used to emphasize a state or situation that is extreme or complete, and does not involve any mix-up with anything else (does not involve anything else).

Tent Curtain Pixabay image by Unsplash

In the 1175-1225 period or Middle English word sheer (scīr, scere, shere, schere, shire) (cognate with German schier, old Norse skīr, Gothic skeirs) was used for a clear, free, bright, thin, shiny or water like material. Some of the synonyms are: utter, complete, absolute, total, pure, perfect, downright, out-and-out, thorough, thoroughgoing, through and through, consummate, patent, surpassing, veritable, unqualified, unmitigated, unalloyed, unadulterated, unmixed. 

Old Window with curtain Pixabay image by Paul Brennan Winder/USA

A Sheer fabric has three basic qualifications: It is thin or lightweight, It is translucent, and it is very supple. The lightweight features come from the quality of fiber material, its filament or spun thread (denier), the low density construction through knitting or weaving. Its translucency derives from sectional form of the fiber, degree of spinning, massing during spinning and weaving, and minimal or no addition of processing materials like dyeing, sizing, etc. Its suppleness results from the quality of fiber material, the low denier of fiber or filament, and avoidance of massing during spinning and weaving.

Sheer curtain with pattern > Pixabay Image by Unsplash

Sheer fabrics from natural fibres such as Silk, have yarns with multiple fiber stands, whereas Cotton has several staples entwined during spinning. The natural fibres create a fabric that is dull or with small sheen. Rayons are produced as staples, and so have slight sheen, unless treated differently. Synthetic fibres such as Nylon and Polyesters are filaments or very long staples, and usually with uniform cross sectional shape, and so provide glossy face.

Sheer curtains > Flickr image by Ket

Sheer fabrics are made from very thin threads and have low density construction, through mainly weaving, but sometimes through knitting. Sheer fabrics of netting type have comparatively low gloss due to greater de-fraction of light. Denser weaves have more sheen or shine. The density of a fabric (knitted or woven) is determined by several factors such as sectional form the fiber, degree of spinning, massing during spinning and weaving. The resultant fabrics have various levels of translucency. Sheer fabric of low density weave is supple, but a flimsy cloth.

Occluding the view with sheer fabric > Wikipedia image by TriviaKing (talk)DWS-Montag Zen

Denier is a unit of measurement for fineness of fibres or filaments, as threads, expressed as the weight in grams for 9,000 metres length of yarn. The surface area of a fabric is directly related to the denier. Smaller deniers yield more fibres per unit weight of the material. A micro-fibre is less than 1 denier, fibres for sheer fabrics are finer, just 0.9 denier, in comparison, a human hair is 20 denier.

Fabrics with a high denier measure are bulky, sturdy, durable, but nearly opaque, whereas fabrics with a low denier measure tend to be sheer, soft, and smooth. A fabric, of 3-5 denier is like a clear film, extremely thin. Ultra sheer refers to very light deniers of stockings or pantyhose, usually 10 or less.

 Sheer fabrics have a crisp to soft feel, depending on the quality of fibres and the density of weave. Fabrics’ coarseness or fineness, are mainly due the techniques of weaving. It is measured in warps or ends per length and in wefts or picks per length. Sheer fabrics include: Silks, Cotton, Rayon, Nylon, Polyesters and other synthetics. The fabric forms are crispy organdy, organza, voile, lawn, Georgette. Supple forms include natural silk (unsized), artificial silks, rayons, tulle, netting, gauze, Gossamer, muslin. Soft sheers are difficult to stitch in comparison to crisp sheers. Art Silk or artificial silks are heat and chemically treated, or co-spun with rayon, cotton and silk staples to achieve desired level of feel.

Glow curtains Pixabay image by Pexels

Sheer fabrics are favoured for garments and draperies due to the suppleness (fall, contouring), transparency and low weight. Sheer fabrics are too thin to control incoming sunlight, but cause its de-fraction. As a curtain the sheer fabric allows sunlight to pass through during daylight, while maintaining a level of privacy.  

Early glass for windows was a flattened plane from cylinder or a flat cast sheet, but available in small sizes. Flattened glass had crinkles, whereas the cast sheet was unevenly polished. The vision through it was distorted, muddled or frosty. The sheer curtain masked the vision through the window. Sheer curtain fabrics do not offer any insulation against heat or cold, so need additional layer of heavy-opaque fabric curtains. Sheer curtains over bedsteads provide a romantic transparency. Sheer fabrics of low denier and high count weaves have little sound absorption, but higher proportion of gather or creases which add to sound absorption capacity.

Green Hued Sheer curtain > Flickr Image by Jessie Lynn McMains

Sheer fabrics for curtaining look best in their natural colours (original colour of the constituent fiber) or very lightly dyed or bleached shades, such as white, off-whites, cream, ivory, shades. Though many base-shades and prints are available. Lighter colours are preferred, due to the greater capacity to defract the light. Colour tinted sheer fabrics were popular to tinge the room with the particular hue. This is no longer needed, as vast varieties of paints and wall finishes with subtle variations of hues are available.

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