(xiv) Low Shrink Fibre: This fibre shrinks only less than 1 % in hot air at 180 deg C in 20 minutes. Fibre is available in 1.5, 2.0 and 3.0 D in all usual cut lengths. Suggested end use is filter fabric for hot air / hot liquids in process industries. One idea is to use this 100% low shrinkage fibre yarn for weaving fabrics of finished width equal to the reed space of the loom.
(xv) Full Bright and Full Dull Fibre: Titanium di oxide is added during polymerization to make the fibre appear dull. By varying the amount of this delustrant, different lustres could be produced such as
It is recommended to spin these fibres in 100% polyester. Then use yarns of different lustres in warp way and weft way or both ways to get shadow stripes or checks.
(xvi) Fibres of Different Cross Sections: By changing the shape of holes in the spinnerets, it is possible to have fibres with different shapes. Some of the more known fibre shapes are:
(i) Flat - Available in 3.3 Den. gives a unique feel and handle to the fabric. Recommended for furnishings.
(ii) Trilobal - A true Trilobal fibre does not give glitter but a soft feel.
(iii) Triangular -what is called trilobal in India is essentially a triangular fibre with a slight curve in all the 3 sides. This fibre is made with full bright polymer i.e. with a TiO2 level of 0.05%. the shape makes light falling on the triangular fibre to reflect repeatedly from inside and so gives a glittering appearance. This fibre is made in coarser deniers of 2.5 and 3.0 D in 51 mm. (Coarser denier fibre gives better glitter). This fibre is used in 15 - 25% blend with regular fibres in fibre dyed suiting. Occasionally some mills have spun 100% triangular yarns for weaving some special fabrics.
(iv) Dog bone / kidney shaped - Used in coarser denier for furnishing end use.
(xvii) Hygiene Fibres: This is a two polymer fibre with-- polyester / polypropylene. This fibre is highly water absorbent, is non-toxic and has a feel of natural cotton. Is available in 2.0 and 6.0 Den. Recommended end uses are disposable diapers, feminine napkins and under pads.
(xviii) Low Melt Fibre / Binder Fibre: This fibre is used for bonding polyester webs in non wovens. Earlier chemical binders were used to bind the webs. But then because of pollution problems, most non-woven producers have shifted to these low melt binder fibres. These are essentially sheath and core fibres. Sheath is a modified polyester polymer that softens at 110 deg C while the core is standard polyester. This fibre is available in 2, 3, 4 and 6 deniers in 64 mm cut lengths. Normally about 15% binder fibre is used. One fibre producer's binder fibre has 50% cross section with low melt polymer. So lower quantities of binder fibres are needed.