OFF-CLIP: See SCALLOPED SELVAGE.
- A term to describe the difference between the percentage of warp crimp and the percentage of filling crimp.
- A term referring to a fabric in which the number of ends and the number of picks per inch are not equal.
OILCLOTH: Any fabric treated with linseed-oil varnish to make it waterproof. It comes in plain colors and printed designs and is most commonly used for table covers or shelf covering. It has now been widely replaced by plastic coated fabrics.
OILPROOF: A term describing fabrics that are impervious to oil.
OIL-REPELLENT: A term applied to fabrics that have been treated with finishes to make them resistant to oil stains.
OLEFIN FIBER: A manufactured fiber in which the fiber-forming substance is any long chain synthetic polymer composed of at least 85% by weight of ethylene, propylene, or other olefin units. Olefin fibers combine lightweight with high strength and abrasion resistance, and are currently being used in rope, indoor-outdoor carpets, and lawn furniture upholstery. (Also see POLYETHYLENE FIBER and POLYPROPYLENE FIBER.)
OLEOPHILIC: A term describing a substance that has a strong affinity for oils.
OLEOPHOBIC: A term describing a substance that does not have a strong affinity for oils.
OLIGOMER: A polymer molecule consisting of only a few monomer units.
OMBRÉ: A color effect in which the shade is changeable from light to dark, generally produced by using warp yarns of different tones. Ombré effects may also be produced by printing.
ONDULE: A general term for plain-weave fabrics of silk, cotton, or manufactured fiber having a wavy effect produced by weaving the warp or filling, but usually the filling, in a wavy line. An ondule reed is generally used to produce this effect, often in a leno weave to emphasize the wave. Ondule is used for dress fabrics.
ON-STREAM: The state of having been brought into production. The term is usually used for chemical and metallurgical plants or processes.
OPEN FACE: A fabric defect consisting of an open appearance of the fabric which permits the filling to “grin” through the warp ends in the center portion of the fabric.
- A preliminary operation in the processing of staple fiber. Opening separates the compressed masses of staple into loose tufts and removes the heavier impurities.
- An operation in the processing of tow that substantially increases the bulk of the tow by separating the filaments and deregistering the crimp.
OPTICAL BRIGHTENER: 1. A colorless compound that, when applied to fabric, absorbs the ultraviolet radiation in light but emits radiation in the visible spectrum. 2. Fluorescent materials added to polymer in manufactured fiber production that emit light in the visible spectrum, usually with a blue cast.
OPTICAL PROPERTIES: A general term used to refer to the relations of yarn or fibers with light. It includes such parameters as birefringence, refractive index, reflectance, optical density,etc.
OPTIMUM TWIST: In spun yarns, a term to describe the amount of twist that gives the maximum breaking strength or the maximum bulk at strength levels acceptable for weaving or knitting.
ORGANDY: A very thin, transparent, stiff, wiry, muslin fabric used for dresses, neckwear, trimmings, and curtains. Swiss organdy is chemically treated and keeps its crisp, transparent finish through many launderings. Organdy without chemical treatment loses its crispness in laundering and has to be restarched. Organdy crushes or musses but is easily pressed. Shadow organdy has a faint printed design in self-color.
ORGANZA: A stiff, thin, plain weave fabric made of silk, nylon, acrylic, or polyester, organza is used primarily in evening and wedding attire for women.
ORGANIZE YARN: Two or more threads twisted in the singles and then plied in the reverse direction. The number of turns per inch in the singles and in the ply is usually in the range of 10 to 20 turns. Organzine yarn is generally used in the warp.
ORIENTATION: In linear polymeric structures, the degree of parallelism of the chain molecules. through which the polymer flows in the manufacture of fibers.
ORTHO: A chemical prefix, usually abbreviated o, signifying that two substituents appear in adjacent positions on a benzene ring.
OSNABURG: A coarse cotton or polyester/cotton fabric, often partly of waste fiber, in a plain weave, medium to heavy in weight, that looks like crash. Unbleached osnaburg is used for grain and cement sacks, and higher grades are used as apparel and household fabrics.
OTTOMAN: Heavy, large, filling rib yarns, often of cotton, wool, or waste yarn, covered in their entirety by silk or manufactured fiber warp yarns, characterized this fabric used for women’s wear and coats.
OVEN-DRY WEIGHT: The constant weight of a specimen obtained by drying in an oven under prescribed conditions of temperature and humidity.
OVERCUT: A staple fiber that is longer than nominal length. Usually, the length is a multiple of 2, 3, or more times the nominal length. An overcut is caused by the failure of filaments to be cut to the desired length during staple manufacture.
OVERLENGTH: See OVERCUT.
OVERSPRAYING: A term sometimes used to describe the application, by spraying, of a fiber lubricant to staple fibers during opening and blending.
OVER-THE-COUNTER: A term that usually refers to direct sales to a retail customer in a store, as opposed to wholesale marketing.
OXFORD CLOTH: A soft but stout shirting fabric in a modified basket weave with a large filling yarn having no twist woven under and over two single, twisted warp yarns. The fabric is usually made from cotton or polyester/cotton blends and is frequently given a silk like luster finish.
OZONE FADING: The fading of a dyed textile material, especially those in blue shades, caused by atmospheric ozone, (O3).