BACKED FABRIC

Backed Fabric-Prof. H. R. Shah 1

Backed cloths The backed fabrics are those, which are produced with extra threads in one (only) series to achieve any of following objects. 1. To increase the warmth-retaining qualities of cloth 2. To impart greater weight and substance than single structure with equally fine surpace

appearance 3. Many times to ornament the fabric without purpose of increasing weight 4. Both for increasing weight and ornamentation

The extra weight can be obtained in an economical manner with the help of backing threads, because the material, which is inferior to the face yarns may be used on the underside. Types of backed fabrics Backed cloths can be constructed on two principles. 1. Weft backed, and 2. Warp backed cloths.

In weft-backed fabric two series weft threads and one series of warp threads are used. In case of warp-backed fabrics two series of warp yarns and one series of weft yarn is used. If 2 series of the threads are used in both directions it produces double cloth. Principles of tying or stitching When the extra (backing) threads are used for the purpose of increasing weight, two things should be observed carefully. 1. Backing threads (underside of fabric) should be bound to face structure with the proper

degree of firmness and 2. The backing threads must be totally invisible from the face side of the cloth.

The tying of extra threads can be done in many ways, which are common to the different classes of the cloth. The backing threads lie at the back of the cloth and they occasionally are raised on the surface for tying. The schemes for tying are many.

To avoid the formation of marks in the face of cloth due to tying, the backing thread should float, between the floats of face weave. Therefore, the positions of stitches should be chosen carefully. For this reason the face weave determines the arrangement of ties, which is most suitable. The following orders of distributing the ties are in general use 1. Twill order is used for twill face weaves. 2. Sateen order used for twill weaves, where loose binding is permissible 3. Plain order for certain weaves, where firmness is desired 4. Irregular order, used for irregular weaves

When backing threads are used in warp, the backing threads are tied between the warp floats. Similarly, when backing threads are used in weft, they are tied between weft floats. Usually, the backing thread is floated (raised) over only one face thread at a place. But, some times it may be raised above two (or more) consecutive face threads. This would impart additional firmness to the structure. This can be done only if the floats of face weave are suitable and the backing yarn is not too thick (i.e. coarse).

The firmness obtained by tying should be of proper degree, because the solidity, strength and wearing properties of cloth are influenced by it. For firm handle the ties should be frequent, and for soft hand ties it may not be that frequent. A 3/3-twill face weave gives greater scope for variety of stitching than other weaves. But, the firmness of stitching can be varied as per requirements. Plain order of stitching can be used for matt weave with face: back ratio as 2:1. For other suitable face weaves, plain order of stitching can be used.

BACKED FABRIC

Backed Fabric-Prof. H. R. Shah 2

Whenever possible it is advisable to get same number of ties on each thread in a repeat. It should also be observed that the ties are distributed uniformly over the repeat area. Certain other points to note are:

In stitching twill weave in twill order; ties should be fill equally on each warp and weft twill line. Other wise adjacent twill lines will appear different from each other.

The ties in above case should not run in opposite direction or twill on face. Other wise it will form cross twill in fabric.

In both extra weft and extra warp systems of producing backed cloths the order of stitching decides the weave on the underside. Therefore, for certain weaves back weave may be-i) same as face or ii) loose back weave giving soft handle to the fabric.

Weft Backed Cloths In weft-backed cloths, there is one series of warp and two series of weft threads. As the

tension on weft during weaving is much less than warp, the weft with less twist can be used. This gives the cloth softer and lofty handle. So, for this purpose, weft backing may be preferred over warp backing. The backing weft used can be cheaper material. This can compensate to some extent for the increase in cost due to extra weft threads. The standard orders of arranging the picks in weft-backed cloths are:

1Face: 1 back

2 Face: 1 back

3 face: 1 back

2 face: 2 back

4 face: 2 back Last two arrangements i.e. 2:2 and 4:2 are used when back weft is different than face

weft. This requires multiple box loom having boxes on one side. 1:1 ratio is used mostly for finer cloths with similar count of face and back weft. 2:1 arrangement gives cheaper production than 1:1 as the backing (extra) threads are less, and the backing thread is coarser so cheaper. But, fabric is coarser underside, so less attractive. Method of designing Following steps are followed to develop the design 1. Mark the face weaves. 2. Introduce the backed picks and shade them to separate from face picks. The backed

picks are introduced in the ratio chosen. 3. On face pick mark the face weave. 4. Insert stitches at suitable places. The care is taken to have face weave mark above and

below stitching mark. This arrangement will conceal (hide) the ties from the face of fabric. Reversible Backed Weaves

In these backed cloths same weave is formed on both sides. This is mainly done for heavily felted cloths with cotton warp and woolen weft. The weft is much coarser than warp and picks per inch are more than ends per inch. Due to this, after felting and raising, warp is completely covered by weft.

Suitable design particulars for 4 end satinatte, 1:1 backed fabric is 2/32 (cotton) warp and 16 (skin woolen) weft, 56ends per inch and 80picks per inch.

By employing two different colors for face and back weft, the cloth having two different colors on both sides is produced. Warp-Backed Cloths In this backed cloths two series of warp threads and one series of weft threads is used. Following points should be noted: 1. The picks/inch are less than weft-backed fabrics.

BACKED FABRIC

Backed Fabric-Prof. H. R. Shah 3

2. More solid appearance can be given to cloth by the formation of stripes on underside of fabric. This is not possible in weft-backed cloth.

3. The warp threads are stronger, so the cloths are structurally superior. 4. The cost is increased due to better quality yarn in warp 5. As ends are more drawing-in cost is more. 6. The drafts are usually more complicated as more number of heald shafts are required to

produce similar effect. The standard orders of arranging the ends in warp-backed cloths are:

1:3, Odd numbered ends can be used.

2:1, in some cases backed weave is combined in stripe or check form with face weave.

3:1 The method designing is same as for weft-backed cloth. The difference being the ends is arranged as face and back in correct ratio. Reversible warp-backed weaves

This is again similar to weft-backed cloths. The weave is same on both the sides. The cloths can be made reversible w. r. t. colouring or color pattern, also. Beaming and drafting of warp-backed designs In beaming there are two cases. 1. All threads can be taken on one beam, if the face and back yarns are similar (count) and

face and back weaves of equal firmness. 2. Two separate beams are made for face and back yarns, if the yarns are not similar and/or

the weaving is of unequal firmness. Drafting 1. Simple patterns may be drawn with straight draft. 2. If the counts are different or material is not similar or if the warp patterns on two sides are

different, or if face weaves requires special draft, then the draft for face and back yarn is separated from each other.

3. Generally, the heald shafts through which backing (weak) yarns are passed are kept at the front. The heald shafts for face yarns (good quality) are placed at back.

4. For more flexibility in the weaves employed in face and back, more heald shafts may be used.

Fabric construction for 2/2 twill 1:1 warp-backed fabric Warp (face and back) 2/40s and weft 20s; 120 epi and 60 ppi Fabric construction for 2:1 face Warp: 30 skein and back warp 20 skein; 60 epi and 40 ppi. Construction of back-cloth

In both types of backed cloths when face threads are finer than backed, in general coarser and poorer quality of yarn is used for backing. The count of backing thread may be 2/3 to of face threads. The face cloth of backed cloth should have 12% less epi and ppi than single structure for twill weaves and less for sateen or loose back; with 1:1 face to back ratio. In 2:1 ratio this is 8% less and 4% less for twill and sateen. Pseudo-Backed Cloth Almost all the ordinary weaves can be modified to produce a structure, which very closely resembles backed cloth. But, in this each thread regularly weaves on both sides of cloth. Advantages: Only one beam is required. Heavy single cloth can be produced having fine surface appearance, yet elastic and soft handle.

BACKED FABRIC

Backed Fabric-Prof. H. R. Shah 4

But, inferior quality yarn cant be used and the colors cannot be effectively used as in backed fabrics. Method to produce imitation design: 1. Take a standard weave. 2. Mark a repeat (for 1:1 ratio) on one thread less or more than twice the number or threads

in the original repeat of weave. 3. Consider the ends of original repeat only and mark the original weave on alternate

horizontal space on first section and then in other section. The designs should be woven with picks, which are twice than ends per inch. The long weft floats on the underside give the appearance of a loose or sateen back weave. This gives resemblance to weft-backed structure. The imitation warp backing designs are developed on similar principles. Backed Cloth With Wadding Threads

The object of wadding threads is to obtain the increased weight i.e. more than just backed cloth. Introducing thick, cheap yarn between the face texture and the backing threads achieves this object.

In weft backed cloths the wadding threads are introduced in the warp and in warp backed cloths wadding threads is introduced in weft. As these fabrics consist of two series of threads in each direction.

The threads may be arranged either one face and one wadding or 2F 1W and these are used with 1:1 and 2:1 backing ratio 2 face, 1 wadding arrangement allows thick wadding yarn to use resulting in higher weight of cloths. Weftbacked warp-wadded designs: The construction of design is easy. Following steps are followed. 1. Decide the face weave and mark it. 2. Draw a repeat with backing threads and wadding threads in pick direction and ends

direction and shade these ends and picks for separation from face ends and picks. 3. Insert the marks of original weave on face ends and pick up. 4. Give markings for ties as per the order decided according to face weave. 5. Insert dots in squares having face picks and wadding ends. The dots indicate wadding

threads (ends) are left down on face picks. The blank in square having back pick and wadding end means the wadding ends are raised above backing picks. Due to this the wadding threads lie between face texture and backing picks. Thus, the wadding-threads do not interweave with face or back picks.

Warp-backed weft wadded cloth These are similarly developed by using wadding threads in picks and backing threads in

ends (warp). The development is on similar principle as explained above. In the last stage, the face ends are lifted on wadding picks shown by dots in squares, which have wadding pick and face end.