Other Mechanical finishing Treatments By: engr. m,. Faiza ANWAR

What is Heat Setting? Heat setting of synthetic fabrics eliminates the internal tensions within the fiber generated during manufacture and the new state can be fixed by rapid cooling. This heat setting fixes the fabrics in the relaxed state and thus avoids subsequent shrinkage or creasing of fabric. Presetting of goods make it possible to use higher temperature for setting and also has a favorable effect on dyeing behavior and running properties of goods.

What is Heat Setting? On the other hand, post setting can be combined with some other operations such as thermosol dyeing or optical brightening of polyester, post setting as a final finish is useful to get a high dimensional stability along with desired handle.  The application of heat in heat setting can be done by hot air,  on a pin stenter at 220 C for 20-30 seconds for polyester goods and at a lower temperature range of 190-210C for 15 -20 seconds for polyamides .  Acrylics may be heat set partially at 170-190 c for 15-60 seconds to reduce formation of running creases.  but higher temperature should be  avoided to prevent yellowing.

Precautionary measures Before the material is heat set, it should be thoroughly washed to remove spin preparations, lubricants, sizing agents and impurities as these are likely to be burnt in drying heat setting making their removal difficult. Fabric should be uniformly dry as uneven moisture causes the fabric to dry unevenly and therefore be subjected to uneven heat setting.

SHRINKAGE? Tensions in Spinning, Weaving, Textile Processing. Fabrics are stretched mostly in length during manufacturing and processing. False dimensions of Fabric are achieved. Becomes true during laundering To shrink fabrics before washing by mechanical means on sanforizer machine, i.e. Sanforizing.

Sanforizing is a process where by the fabric is run through a sanforizer; a machine that has drums filled with hot steam. This process is done to control the shrinkage of the fabric. The fabric is given an optimum dimensional stability by applying mechanical forces and water vapour. Sanforizing is a controlled compressive shrinkage process, which is applied on woven fabric to achieve shrinkage before making the garments. After sanforizing the residual shrinkage of woven fabric may be zero.

Sanforizing In sanforizing process shrinkage is achieved by passing the cotton fabric onto a movable elastic felt blanket. Sanforizing process is based on the principle that when a elastic felt blanket is passed around a metal roller in contact with it, its outer surface in process extended and the inner surface contracted. So the process is called controlled compressive shrinkage process.

Sanforizing Machine Mechanical Type The Fabric (F) Guide Rollers (G) The skyer (S) or moistening device The clip expander (C) Endless rubber belt (R) Pressure roll (P) Rubber belt cylinder (RB) The dryer (D)

Raising This is the technique used to achieve by scratching or pulling out of the individual fibers from the yarns by means of wire brushes. Two main types 1. Napping Using wire-covered rolls to "dig out" individual fiber ends to the surface. 2. Sueding Using abrasive-covered rolls (sandpaper, emery cloth, etc.) to produce shorter pile surface - does cause an apparent shade change

Napping The raising of the fibre on the face of the goods by means of teasels or rollers covered with card clothing (steel wires) that are about one inch in height. Action by either method raises the protruding fibres and causes the finished fabric to provide greater warmth to the wearer, causes the fabric to become softer in hand or smoother in feel; increase durability and covers the minute areas between the interlacings of the warp and the filling. Napped fabrics include blankets, flannel, unfinished worsted, etc. Other names for napping are Gigging, Genapping, Teaseled, Raised.

Raising Machines Napping Emerizing

Sanding, Sueding or Emerizing It is known as sanding as it uses Sand paper or emery paper to abraid the surface to produce a suede like appearance. surface finish, most commonly used with cotton fabrics, less commonly with woollen fabrics. Fabric undergoes treatment by abrasive roller with the use of emery or glass powder paper. A smooth pile forms on the surface of the fabric, giving a soft, velvet-like touch.

Sanding, Sueding or Emerizing The abrasive material is wrapped around rotating rollers over which the fabric passes. The effect of this is to cut some of the fibers which go to make up the fabric and so to produce an abraided appearance on the fabric. This produces a peach skin effect giving soft feel and touch.

Emerizing Peach Skin Suede Leather

References Eurotex, Vol. IV, Textile Wet processing. more: http://textilelearner.blogspot.com/2011/03/description-of-textile-finishing_1796.html#ixzz1zim7HUo1