Study of cotton woven fabrics with added polybutylene terephthalate(pbt) yarns

The aim of this work is the development of new products,i.e.cotton like woven fabrics with increased extensibility,using textured multifilament polybutylene terephthalate(PBT) yarn in the weft direction and a proper finishing procedure.For the research purpose,a set of referential samples of woven fabrics containing PBT was made.The fabrics differed in the sequences of cotton and PBT yarns in the weft direction.In some samples a doubled PBT yarns is inserted in as one weft,simulating double linear density.The inflence of the textured PBT yarn quantity on the elastic properties of cotton/PBT woven fabrics,developed after the treatment in boiling water for 30 minutes,was studied.The contraction in warp and weft directions that affect warp and weft density,thickness,mass per unit area and tensile properties were measued using standardised methods.The quantity of PBT mainly infulenced the elasticity in weft direction.The highest elasticity correlated well with the highest quantity of PBT.Furthermore,a minimum portion of PBT effectively improved the tensile properties of treated fabrics in both directions,this being imortant in such case,as the fabrics mostly keep their cotton character.The use of PBT and proper finishing procedure for developing the required increased elastic properties of woven fabrics for any purposes could be of significant advantage concerning the price (compared to Lycra)and production time(preparation for weaving and speed of weaving)

1.Introduction:

The trend is producing fabrics with increased elasticity,which is comfortable and easy to maintain with a nice handle.There are several problems,how to produce that kind of fabrics with low costs.The so-called stretch fabrics are usually made from different materials.At least one of them have highly elastic properties.The most frequently used is Lycra,with an be expensive and cause problems in the maintainances since to retain the elasticity,it can't be washed at temperatures higher than 40 degree.Lately,there have been new,more reasonably priced materials with elastic properties.One of such materials is polybutylene terephthalate(PBT).The price of PBT is higher than the most frequently used polyester polyethylene terephthalate(PET),but cheaper than elastane and cotton yarns.We expect that their use in an optimal portion can improve the tensile properties(increase the extensibility)of cotton fabrics and consequently,make fabrics less expensive and less complex for the production at the same time.

1.Washing treatment had a significant effect on the elongation and permanent elongation values of the fabric samples containing PBT.After washing,the elongation value of PBT filament fabric sample was increased 57.2% in weftwise and 1.4% in warpwise,while these values of PBT/Cotton fabric sample in weft and warpwise were increased 33.6% and 3.4%,respectively.Additionally the PBT Filament and PBT/Cotton fabric samples' permanent elongation values were increased by 9% and 9.8%,respectively.

Study has been conducted on the mechanisms of PBT yarn incorporated in the structure of cotton fabric.The interaction between yarn properties and weave geometry had a strong influence on physical and mechanical characteristics before and after the thermal treatment.

2.Theoretical part

It is know that elastic fibers can greatly improve characteristics of woven fabric made from natural cotton fibers.Used is multi filament tetured PBT yarn and can be used for product:ready-to-wear,knitingwear,jeans,casualwear,sportswear,as well as in specialized and medical fields.PBT textured yarn has latent elastic properties that become obvious after the thermal treatment,e.g.dying,PBT is dyed at temperature 100 degree.The construction of fabric,as well as finishing procedures applied,should be pre-programmed,when adding Lycra.Elstane yarn can be replaced with chemically and thermally more stable highly elastic fibers with over 100% elastic elongation,e.g.bicomponent elastomultiester(EME),elastolefin(CEF)triexta fibres and polyester PBT.Textured yarns are characterised by highly elastic perperties with elastic elongation over 10% that develop after a high-temperature treatment process,where two dimensional crimps change into three dimensional ones.These latent elastic properties of textured PBT yarn were explained by the changes in the crystal structure of fibres.



Writen by Dijana Strukelj,BSC,Prof.Krste Dimitrovski,PhD,University of Ljubljana,Faculty of Sciences and Engineering.