There are two types of disperse dyeing processes.
(ii) HTHP
Explanation of the second method -
High-Temperature High-Pressure Dyeing Method (HTHP)
Principle of HTHP Dyeing - This process uses pressurised equipment to dye polyester fibre at high pressure and temperature (over 100°C in an aqueous bath).
The HTHP conditions assist in raising the fibre's temperature above its optimal level, allowing for effective T diffusion and producing favourable dyeing outcomes.
Types of HTHP Dyeing
- Pressure Jigger
- Pressure winch
- Package dyeing machine
- Jet dyeing machine
HTHP method by beam dyeing machine:
The length of the material to be dyed is carefully wound onto a performed beam and put inside the dyeing apparatus in beam dyeing.
Up until the dyeing is finished, dye fluid is systematically circulated into the material under high temperatures.
The fabric must be correctly wound on the beam and kept under consistent tension during extreme temperature beam dyeing to urge an identical shade along the complete length of the coloured fabric.
It's advised to utilise carefully made batching equipment that guarantees uniform batching of the material with mild but even tension throughout the batching.
Both too tight and too loose batching should be avoided. Lapping cloth product of loosely woven yarn is first applied to the beam.
To prevent the material roll from slipping and to forestall perforation marks, eight to 10 layers of this kind of fabric are enough.
The length by which the fabric goes beyond the beam's perforated region must even be taken into consideration when batching.
The dye fluid will typically choose the route with the smallest amount of resistance.
Since resistance must be as consistent as possible across the roll of cloth on the beam, including the perimeters, a bigger overlap is required beyond the perforations.
The roll's thickness has a bearing on how dense the fabric is. it's important to not ignore the selvedges' extremely high density. deficient overlap causes the fabric to be coloured paler at the material's outermost selvedges because there's not enough dye liquor flowing there to hide the selvedge.
Counting on the fabric's quality and density yet because of the roll's thickness, the
selvedges should overlap the perforations to a specific level. With weave, for example, even for a rather thick roll, an overlap of 3-5 cm is usually sufficient.
A later section on dispersion dyeing issues discusses the problems associated with insufficient tolerances at the perimeters of the perforated area on the beam.
Advantages of the beam dyeing machine
(ii) Loading and unloading the material is easy and also the dyeing process lasts a brief time;
(iii) thanks to the low M:L ratio typically employed in beam dyeing, much but the standard quantities of the dyeing assistants and sometimes the dyes are required for
(iv) This device can colour both yarn and fabric. yarn within the kind of a warp beam is meant for dyeing.
Disadvantages of the beam dyeing machine
(ii) It's impossible to dye multiple fabrics on one beam that are various widths.
(iv) If the beam is loaded, uneven dyeing could happen because the dye fluid must permeate many layers of cloth.
(iii) Shrinkage may cause the coloured fabric to exhibit a moiré look if it's pressed firmly.
(v) Faulty dyeing happens if the material isn't coiled neatly and consistently and if wrinkles are allowed to develop. After dying, the wrinkles remain there forever. Patchy dyeing, selvedge to centre shade change, tailing effect, etc. are further issues that may arise from poor batching.
Questions -
- What is the HTHP method? and how it is used for disperse dyeing?
- What is the beam dyeing method for disperse dye?
- What are the advantages and disadvantages of the HTHP method?
References
Disperse dye additives. (n.d.). Borregaard.com. from https://www.borregaard.com/markets/dyestuffs/applications/disperse-dyes/
Dyeing polyester with disperse dye. (n.d.). Pburch.net. from http://www.pburch.net/dyeing/dispersedye.shtml
Gurr, E. (1971). DISPERSE DYES. In Synthetic Dyes in Biology, Medicine and Chemistry (pp. 691–702). Elsevier.
Holland, A. (n.d.). Disperse Dye for dyeing and printing polyester and sythetic fabrics. Georgeweil.com. from https://www.georgeweil.com/blog/disperse-dyes-for-dyeing-and-printing/
Transfer/disperse dyes - how to. (n.d.). Vycombe-arts.co.uk. from https://www.vycombe-arts.co.uk/transferdyes.html
Wypych, G. (2013). Weathering of compounded products. In Handbook of Material Weathering (pp. 581–717). Elsevier.
(N.d.). Textilelearner.net. from https://textilelearner.net/disperse-dyes-dyeing-and-printing-method/
Continue reading,
Part 2 Method of carrier Dyeing of Disperse dyes
Part 3 Method of HTHP Dyeing of Disperse dyes
Part 4 Other methods for disperse dyeing
