(xix) Hollow and Hollow Conjugate Fibres: Simple hollow fibres- with single hole or multiple holes-are used for stuffing- in siliconised finish for pillows and in non-siliconised version for quilts and furniture. These fibres are usually made out of recycled polymer. The hollow conjugate fibre is a core and sheath fibre with polymers of different viscosities. A spiral crimp develops due to differential shrinkage properties of the 2 polymers. This fibre is available in 3, 4.5, 7 and 15 deniers in 64 mm cut lengths. It is also given an anti bacterial finish. Recommended uses are - soft toys, pillows, furniture and non woven padding, bedding etc.
(xx) Short Cut PSF: This is standard polyester fibre of denier from 0.5 to 7.0 denier cut to a short length of 3, 5, 6 and, 12 mms. It is treated with a different spin finish that enables this short fibre to disperse easily in aqueous solutions. This fibre is used for reinforcing paper, plastics, rubber and concrete and can be employed as filter media in automobile air filters, vacuum cleaner bays, battery separators, in R/O separate medias and in synthetic and specific papers. Author has personal experience with this fibre in Paper Industry. Additions of 2% of this fibre increase tear strength of paper by 20 - 25%. India is short of good pulp for making quality papers and so a considerable quantity of paper is made by blending recycled used paper. Every time paper is recycled, the mean fibre length of the cellulose fibre in paper shortens and affects tensile and tear strengths. This is where short cut polyester can help in reinforcing recycled blended paper.
(xxi) Perfumed Hollow Fibre: Some fibre producers offer hollow fibres with perfumes put inside the hollow. Ranges of perfumes vary from floral to those of mountain air.. Both pillows and quilts are available with perfumed hollow fibres. Producers claim sound- peaceful- stress free sleep is obtained using pillows and quilts containing perfumed fibres, but then perfumes being volatile, the fragrance is lost in a few months.
(xxii) Water Sensitive Fibres: These are fibres which contain sensitive pigments, when dry, the pigment has one colour, when wetted with water, and the colour alters. Recommended end use is swimsuits. So when a swimmer having said red swim suit jumps into swimming pool, the swim suit changes its colour say to green. On drying the original colour reappears
(xxiii) Anti static or Conducting Fibres: By adding fine stainless steel powder polyester fibre is made fully conductive. Fibre is recommended for use as carpets in computer rooms to allow static charges - if any- to leak away.
(xxiv) Optically Bright or Optically White Fibres: These fibres are usually made with bright polymer and by adding at least 180 ppm of optically brightner usually in bluish or violet tinge. The final fabric has an excellent milky white appearance and retains its whiteness for a much longer period. Ideal for office wear and uniforms.
3 Speciality Polyester Filament Yarns
3.1 As mentioned earlier, most specialities are available in both staple fibre and in filament form.
3.2 Additional Speciality Polyester Filament Yarns: