A study has been carried out to correlate the wet fastness properties of dyed knitted fabrics, derived from both poly(ethylene terephthalate) and poly(lactic acid) (Ingeo) fibres, with the thermal migration properties of the disperse dyes during heat treatment. The results indicate a greater amount of disperse dye at the surface of the Ingeo fibre fabric than the poly(ethylene terephthalate) fabric, after post heat‐setting using the conditions needed for fabric stabilisation, correlating well with its slightly lower wash fastness properties.

A study has been conducted into the effect of heat setting on the dimensional stability and dyeing properties of spun and false‐twist texturised poly(lactic acid) yarn. It has been shown that acceptable levels of dimensional stability can be achieved after heat setting for 30–45 s at 130 °C, false‐twist texturised yarn exhibiting greater shrinkage than spun yarn. The exhaustion level and visual colour yield of a number of disperse dyes have been evaluated on each type of poly(lactic acid) yarn and shown to be essentially independent of the time of heat setting.

A study has been conducted to examine the effect of different preparation and dyeing processes on the physical strength of the Ingeo fibre component of an Ingeo fibre/cotton blend. An alkaline scouring process (for the cotton), followed by a two‐bath, two‐stage dyeing process in which the Ingeo fibre underwent a simulated dyeing with disperse dyes, followed by the cotton being dyed with reactive dyes, caused minimal deterioration to the strength of the Ingeo fibre. However, it is considered that problems might arise if the Ingeo fibre was subjected to prolonged dyeing times, particularly at neutral or alkaline pH, e.g. if an excessive number of shading additions needed to be carried out.

A study has been conducted to examine the effect of a vigorous alkaline scour–bleaching preparation, followed by high temperature dyeing, reduction clearing and a reactive dyeing process on the physical strength of the Ingeo fibre component of an Ingeo fibre/cotton blend. The results indicate that the physical strength will be retained at a technically‐ and commercially‐acceptable level provided that prolonged high temperature processing times are not employed.

The current research studied the dyeing properties and spectroscopic characteristics of natural dyes on PLA and PET fabrics. The natural dyes used were the dyes extracted from turmeric and cassumunar powder and the commercial dyes viz. Natural Orange and Natural Red Brown. The water solubility and partition of the dyes in octanol and water (logP) were studied. It was found that the dyes with poor water solubility that were the turmeric and cassumunar dyes exhibited a high degree of exhaustion and visual color yield (K/S) than the readily water soluble commercial dyes viz. Natural Orange and Natural Red Brown. Turmeric and cassumunar dyes can be used for dyeing PLA and PET fabrics to a medium-deep shade with the turmeric dye providing a deeper shade. The fluorescence properties of the turmeric and cassumunar dyes were examined on the PLA and PET fabrics and it was observed that the dyes exhibited a stronger fluorescence emission on PLA than PET for both turmeric and cassumunar dyes. Cassumunar dye displayed less fluorescence properties than turmeric dyes on both fabrics. The fluorescence emission properties of the turmeric dyes at different K/S levels were also investigated.Index Terms-Natural dye, polyester, polylactic acid, turmeric, cassumunar, fluorescence.

Summary: Eri cocoons were prepared into short fibers and subsequently blended with cotton fiber in order to develop the new fiber blended yarn in the short spinning system. The Eri and cotton fibers were blended using the drawframe blending with varying blending factors, viz. blending composition (0-100%) and yarn counts (30 and 50 tex). The results showed that Eri fiber which was longer and stronger than cotton fiber, affected the fiber distribution in the yarn cross-section. The mechanical properties of the blended fibers and yarns increased with increasing silk content. Longer fibers of Eri silk tended to move towards the yarn core, especially at silk content higher than 50%. Moreover, stronger and more extensible Eri silk fiber gave an advantage to the improvement of mechanical properties of those blended yarns with silk content higher than 50%. However, with increasing silk content, the blended yarns were more irregular as shown in %CV. Concerning the yarn count effect, the higher yarn count of 50 tex resulted in a more regular yarn with higher yarn strength than that of 30 tex. The plain-woven fabrics were prepared using the blended yarns as a weft yarn and the cotton yarn or silk yarn as a warp yarn. The mechanical properties of those woven fabrics were characterized in order to study the influence of silk contents. The results showed that tensile strength, %elongation and tear strength of woven fabrics using the blended yarn were increased with an increase in silk content. This is an advantage of Eri silk in the aspect of rendering the strength to the blended yarns and fabrics.

Abstract-This research studied the extraction of the natural dye from two different types of tamarind seed viz. sour-tamarind seed (TF) and sweet-tamarind seed (TO). The extracted dye solutions were prepared into a powder form and subsequently used for dyeing cotton and Bombyx Mori silk and Eri silk fabrics. From the experiment, the TF dye powder was easier soluble in water and could render a higher color strength than the TO dye powder. It was found for the tamarind-seed dyes that they could better exhausted on the silk fabrics than the cotton. Between the two silk fabrics, the dyes illustrated a higher degree of exhaustion on Bombyx Mori silk fabric than the Eri counterpart. The tamarind-seed dyes provide a reddish brown shade on the fabrics. This reddish brown shade could be altered when the dyed fabrics were put through the washing process. After washing, the shade of the dyed fabrics was more intense. The color fastness to washing of the dyed fabrics was in a good-excellent level. Even after experiencing 5-time washing, no significant shade change was observed on the dyed fabrics. The effect of mordants on the dyed fabrics was studied using three different mordants which were ZnSo 4 , K 2 Cr 2 O 7 and FeSo 4 . The ZnSo 4 mordant was found to enhance the color fastness to washing to the dyed fabrics without causing any shade change, while using K 2 Cr 2 O 7 as a mordant led to a shade alteration into a yellow brown but helped to stabilize the dye molecule, so such shade obtained was not sensitive to the washing condition. For the FeSo 4 mordant, it also caused the shade change on the dyed fabrics to a dull grey shade but providing an excellent color fastness to washing.

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