Cellulose

A carbohydrate which is the chief component of the cell walls of plants. Cellulose is found in wood and in cotton linen jute hemp and all of the bast leaf and stem fibers. It is a basic raw material in the manufacture of rayon acetate and triacetate fibers.

Cellulose acetate

An ester formed from cellulose and ethanoic acid (acetic acid) (see acetate (fibre)).
Note:Purified cellulose is ethanoylated (acetylated) by ethanoic anhydride (acetic anhydride) in the presence of a catalyst (such as sulphuric acid or perchloric acid) in a solvent such as dichloromethane (methylene chloride) or ethanoic acid, which also acts as a diluent. The reaction proceeds until primary cellulose acetate containing about 60% by mass of combined ethanoic acid is formed. Secondary cellulose acetate is formed from this product by partial hydrolysis. It is obtained by adding water in excess of that required to react with the residual ethanoic anhydride, which thus allows hydrolysis to take place. When the hydrolysis is allowed to proceed until approximately 54% of combined ethaiioic acid remains in the product, the cellulose acetate is soluble in propanone (acetone) and is sometimes known as acetone-soluble cellulose acetate.

Cellulose diacetate

Strictly, an ester of cellulose and ethanoic acid (acetic acid) containing 48.8% by amass of combined ethanoic acid. This, however, is not a commercial textile product. The same term is sometimes used loosely to describe propanone-soluble (acetone-soluble) cellulose acetate. (See also acetate fibre.)

Cellulose triacetate

Strictly, a cellulose acetate containing 62.5% by mass of combined ethanoic acid (acetic acid) but the term is generally used for primary cellulose acetate containing more than 60% by mass of combined ethanoic acid. (See also triacetate fibre.)

Cellulose xanthate

An alkali-soluble salt formed by reaction between carbon disulphide and cellulose in the presence of a strong alkali.

Cellulosic Fiber

A fiber composed of or derived from cellulose. Examples are cotton (cellulose) rayon (regenerated cellulose) acetate (cellulose acetate) and triacetate (cellulose triacetate).

Center Loop

See KINK.

Centering Mark

See CLIP MARK

Centre (point) tie

The order in which the harness cords are attached to the neck cords and their arrangement in the comber board (see jacquard harness (weaving)). The tie is known as:
(i) Norwich or London according to the position of the jacquard and harness in relation to the loom. In the Norwich tie, the harness hangs straight and the card cylinder is at right angles to the warp. In the London tie, the jacquard is placed so that the cylinder is parallel to the warp, the harness having a 90' twist. In either case, various arrangements are possible, for example:
(a) single tie, in which each jacquard needle controls only one harness cord and only one warp thread, there being only one repeat of the pattern in the cloth width;
(b) repeating tie, in which each jacquard needle controls several harness cords and the pattern is repeated several times across the cloth width;
(ii) centre (point) tie, in which each needle controls one warp thread in one half of the pattern repeat and one warp thread in the other, the result being that one half of the pattern is a mirror image of the other;
(iii) border tie, in which some of the jacquard needles and hooks are used to produce a design close to and parallel with the cloth selvedges, the other needles and hooks being used to produce a different design in the rest of the cloth.
Note: Mixed ties (combinations of two or more of the above) are also possible

Centre gimp (lace)

A Leavers-lace construction in which the filling threads, called gimps, lie between the front and back warp threads. The ground net is made by the interaction of two warp threads with each bobbin thread. The objects are filled by traversing gimp threads, according to the requirements of the pattern. Thick threads may be used for outlining the objects.

Centre line (lace machines)

A datum line across the working width of the machine. The setting and adjustment of the machine are related to the centre line.
Note 1: The centre line of the machine lies just below the facing bar across the working width of the machine.
Note 2: The highest position reached by the points is adjusted to the centre line of the machine. (See also Notes under circle (lace machines).)

Centre loop (defect)

A short length of weft yarn that is looped on the surface of the fabric or doubled back on itself in the fabric without snarling. The defect is associated with weft yarn that is not lively and may be caused by inadequate tension control in the shuttle, by shuttle bounce, by the reed being unsuitable for the fabric being woven, or by faulty setting of the weft fork etc. In the last case, it may be referred to as a 'centre loop' defect.

Centre selvedge

A set of threads interlacing with a gauze weave either at the edge or in the body of a fabric. In the latter case, it prevents ravelling when the fabric is severed in the direction of the warp. When in the body of the fabric, a leno edge is often referred to as a 'centre selvedge'. (See also splits.)

Centre weft fork

A mechanical device for monitoring the presence of weft during weaving, normally on shuttle looms. (See also weft detector.)
Note: If this device operates at one side of the warp, between the edge of the warp and the boxes, it is referred to as a 'side weft fork', but if it operates anywhere between the two edges of the warp, it is referred to as a 'centre weft fork'.

Centre-stitching

A compound fabric in which the two component fabrics are held together by one of the following:
(i) centre-stitching, in which a special series of stitching threads, lying between the two fabrics, are interlaced alternately with them and thus bind them together;
(ii) self-stitching, in which threads from one fabric interlace with the other (e.g., by taking a back warp thread over a face weft thread);
(iii) interchanging, in which the two fabrics are so woven as to interchange with each other. In some cases, the fabrics are completely interchanged whereas in others only the warp or weft threads interchange.