Introduction of pigments
When applied to textiles as insoluble particles, "pigments" are finely dispersed insoluble colourants, as hostile to the "dyes" that are discussed within the preceding chapters.
Insoluble pigments are another name for dyes. Rather than using dying procedures, printing is the primary method accustomed apply pigments.
However, as pigment dyeing has also been wont to colour textiles, it's deserving of special attention.
One of the key distinctions between pigments and dyes is that, unlike dyes, pigments are just coated on the surface of the material instead of penetrating the fibre.
Therefore, pigment dyeing is just surface dyeing.
Commercial pigment dispersions have particles that direct size from 0.1 m to 1.0 m. (10-5 to 104 cm).
Both the colour (hue) and tinctorial strength of the pigment particle rely upon its size and shape.
The figure below may be a schematic diagram illustrating the key distinction between dye-fibre interrelationship and pigment-fibre interrelationship.
Pigment dyeing is often limited to light shades, and any textile fabric, whether it's made from cotton, wool, or man-made fibre, is painted with bright colours and metallic colours like gold.
The reality is that pigments aren't actual dyes because they need no affinity for the fibre and are applied to the material and mechanically held in situ by binders, which are then heated to an extreme temperature to cure them.
The definition of a dye, on the opposite hand, could be a colouring agent that's soluble in both the media through which it's applied and in water.
It's possible for them to chemically or physically combine with the fibre.
They then enter the fibre molecular structure and become locked there, as shown within the figure above.
Pigments are anticipated to own good physiological safety, physiological harmlessness, dispersibility, migration, light and weather fastness, and an affordable price for effective commercial application.
Because processing temperatures are typically high, heat resistance is required (i.e. during drying and curing).
Through the employment of specialized tests, light, weather, and migration resistance still as physiological harmlessness are evaluated.
The pigment's particle size affects the hues additionally to its chemical composition and crystallisation.
If the pigment particles are but half the wavelength of the sunshine striking the substance, the pigment-dyed material will look brighter.
The perfect range for pigment sizes is between 0.3 and 0.8 μm. the dimensions of the particles in an exceedingly commercial pigment dispersion range from 0.1 to 1.0 μm.
Both the colour and therefore the tinctorial strength is influenced by the scale and shape of the pigment particle.
Following inorganic pigments are most commonly used in pigments dyeing :
Colour | Content |
White | titanium dioxide, ZnO, ZnS, lithopone (ZnS + BaSO). |
Yellow | CdS (acid sensitive), Fe,O,,xH,O, PbCrO, (chrome yellow), benzidine yellow. flavanthrone yellow. |
Orange | pigments from the anthrac uinone group. |
Red | CdSe, iron oxide red, molybdenum red and many organic substances. |
Bordeaux | CdSe, thioindigo, quinacridone. |
Violet | many organic pigments. |
Blue | ultramarine blue, cobalt blue, manganese blue (BaMnO/ BaSO), phthalocya nine blue. |
Green | chromium oxide, chlorinated copper phthalocyanine. |
Metal powder | aluminium. |
- Describe the working and importance of pigments in fabric chemical processing.
- Explain pigments for fabric.
References
Hussain, T. (2014). Pigment Dyeing and Finishing of Cotton /Polyester Fabrics with a Modified Dihydroxyethyleneurea and various softener treatment. Life Science Journal. https://www.academia.edu/29522602/Pigment_Dyeing_and_Finishing_of_Cotton_Polyester_Fabrics_with_a_Modified_Dihydroxyethyleneurea_and_various_Softener_Treatment
Pigment dyed vs garment dyed: What’s the difference? (n.d.). Nyfifth.com. Retrieved 26 December 2022, from https://www.nyfifth.com/blog/2020/05/26/pigment-dyed-vs-garment-dyed-whats-the-difference/
Pigment Dyeing,Pigment Dyeing process,Pigment Dyeing Method,Pigment Dyed Garments,Pigment Dyed Clothing,pigment dyed fabric. (2011, February 10). Fibre2fashion.com; Fibre2Fashion. https://www.fibre2fashion.com/industry-article/5426/production-process-for-pigment-dyed-garment
ProductIP. (2021, March 8). Dyes and pigments. Productip.com. https://www.productip.com/kb/productipedia/compliance-resources/dyes-and-pigments
(N.d.). Researchgate.net. from https://www.researchgate.net/publication/260797037_Pigment_Dyeing_and_Finishing_of_Cotton_Polyester_Fabrics_with_a_Modified_Dihydroxyethyleneurea_and_various_Softener_Treatment
Part 2 Pigments - Properties and classification
Part 3 Pigment dyeing requirements
Part 4 Application of pigments by the dyeing process
Part 5 Advances Pigment dyeing
