Inventions to the Book of Job

Evidence is presented that confirms the colour changes of a widely used trichromatic mixture of bifunctional reactive dyes (Levafix CA) under alkaline conditions, showing that they occur slowly and throughout the dyeing time, and not instantly after alkali addition to the dyebath. Thus, it is impossible to determine the specific absorptivity of the dyes at each moment of the dyeing process. An investigation into the relationship of the type of reactive group to the dye and the visible spectral changes over time was undertaken. Model reactive dyes were studied. The samples collected from the simulated dyebaths were monitored online using an automated system and their absorption on the whole of the visible spectrum was measured. The studies of dyes that included halo‐s‐triazinyl groups revealed the existence of hypochromic shifts in the spectra of the dyes in the presence of an electrolyte (sodium chloride or sodium sulphate) and bathochromic and hyperchromic shifts, when evaluated in the presence of alkaline agents. However, the vinylsulphonyl derivatives present a more stable spectral profile. The use of buffer solution at pH 5 was an efficient method to stabilise the absorption profile of Levafix CA trichromatic samples.

Section: Influence Of Salt In the Dyebathmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A study on the spectral changes of reactive textile dyes and their implications for online control of dyeing processes

Santos

Soares

Hrdina

et al. 2009

“…Previous researchers have demonstrated that several dyeing control parameters, such as temperature, flow rate, time and pH, can be sufficiently controlled in modern dyeing machines [1][2][3][4][5][6][7][8]. The amount of dyes on a fabric can also be adequately predicted during the dyeing process, with the aid of online dye monitoring and analysis devices [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Prediction of depth of shade of a dyed polyester fabric based on fibre fineness and fabric structure

Shamey

2009

A colour prediction model containing four parameters of dye concentration, fibre fineness, fabric roughness and dye parameter is developed. The model can predict the shade depth of a dyed polyester fabric. The relationship among these factors and shade depths of dyed polyester fabrics was investigated to elucidate the role of fibre fineness and fabric structure on surface reflectance and colour efficiency. The shades of several additional dyed samples were measured and compared against the predicated values to validate the accuracy and performance of the model. The results showed that the predicated depths of shade matched the experimental data to a good extent.

“…In the first two parts of this paper, robust and reliable methods for measuring [1] and controlling [2] the rate of dye exhaustion in a pilot-scale package dyeing machine have been described. This system is capable of producing dyeings of acceptable levelness with exhaustion times as low as 20 min with very good reproducibility.…”

Section: Introductionmentioning

confidence: 99%

Dyeing machine control using in‐line colour measurement. Part 3: Online dyeing quality control

Gilchrist

Nobbs

2000

A system is described that controls the dyeing process so as to produce a package within a final unlevelness tolerance in the minimum time. This is achieved by incorporating into the control algorithm a mathematical model capable of predicting the unlevelness in a dyed package from the current state of the system. The use of such a general strategy allows production of dyeings of acceptable quality in minimum time and requires little intervention from the machine operator.