How Carpet is Dyed by the Mill or Fiber Producer
Carpet is dyed at one of two stages in the manufacturing process:
- PRE-DYED: Dyestuffs are added to the fibers or yarn PRIOR TO the tufting process.
- POST-DYED: The yarn was undyed when tufted and then the unfinished carpet is dyed.
There are four primary PRE-DYED Carpet Dyeing methods:
- SOLUTION DYEING:
In solution dyeing of carpet, dyestuffs are added to the molten polymer before extrusion into a colored filament. As a result, the filament is impregnated with the color pigment all the way through.
The only way to dye olefin is by solution dyeing.
Commercial nylon is also quite often solution-dyed. However, unless appropriate acid dye blockers are applied after carpet manufacturing, solution-dyed nylon can continue to accept acid dyes from food spills, coffee, colas, etc.
There are several advantages to solution dyeing fibers:
- When a fiber is dyed post-production (as in traditional dye methods), the dye soaks into the fiber and fills the fiber’s cells. After being dyed, the fiber appears uniformly colored, at least to the naked eye. However, there are always cells in the fiber that did not absorb the dye - these are known as empty dye sites.
- To understand the difference this makes, picture a radish and a carrot. The radish represents the traditional-dyed fiber, where the color is on the exterior but does not go through. (The radish is red on the outside but white on the inside.) By contrast, the carrot is orange all the way through, in the same way that a solution-dyed fiber has color throughout. As a result, solution dyed fiber is much more resistant to staining.
- Solution-dyed fibers are much more colorfast (resistant to fading or color bleeding) than other fibers. This is because the color is locked into the fibers. So, solution-dyed fiber is a great choice for areas that will be subjected to intense light.
- Also, because the fibers are stabilized during production using ultraviolet inhibitors, they are the best choice for use in outdoor carpet applications.
- Solution-dyed fibers are great for use in commercial carpets.
- The primary disadvantage of solution-dyed fibers is the reduced color selection, compared to other fibers.
- STOCK DYEING: The yarn was undyed when tufted and then the unfinished carpet is dyed.
- SKEIN DYEING: (pronounced “skane”). Dyeing yarn in skein form is used for small lots. Yarn is unwound from cones to skeins and then are mounted and immersed into a large hot dye vat. After dyeing and drying the yarn is rewound onto cones.
- SPACE DYEING: Several colors are printed along the yarn length to produce a tweed effect when tufted.
Most residential carpets are POST-DYED:
- BECK DYEING is primarily for solid colors in limited runs. In this method, the carpet is dyed “in a piece” after tufting but before other finishing processes such as attaching the secondary backing. Large rolls in rope form of uncolored carpet (greige goods - pronounced “gray goods”) are placed in a large vat of dye solution (dye beck), heated to high temperatures, agitated continually while it is soaking up the dye, making the color come out very even from end to end and side to side. It is then removed, washed and dried. This is most commonly used for cut pile carpet. Beck dyeing a roll of carpet usually takes between three to six hours, depending on the color and the amount of carpet to be dyed.
- NOTE: Greige goods is a term designating carpet just off the tufting machine and in an undyed or unfinished state.
- In CONTINUOUS DYEING, the carpet (greige goods) is rinsed and then passed under a dye applicator, which spreads or sprays dyes evenly across the entire width of the carpet. The carpet then enters a steam chamber, where the dyes are “set” into the fibers. This method is for longer runs of both solid and multi-color applications.
- PRINT DYEING is the process of producing a pattern with dyestuffs on carpets and rugs, done with screen-printing, roller equipment or ink jet printers. This is easily checked for in the field by bending over the fiber tuft - if the tuft is only dyed part of the way down, it is print dyed. After print dyeing, the carpet is steamed and dried. Do not use high-pH aggressive detergents on print dyed carpet. This type of dyeing allows tone on tone and multi-color effects. Included in this method are flat bed printing, rotary printing, silkscreen printing and computerized jet spray printing.
- DIFFERENTIAL DYEING: Tufted carpet with yarn treated chemically so that when placed in a dye bath each yarn type will react differently to the dye, resulting in different shades of the same color.
Related Carpet Manufacturing Training Products:
- Carpet Fibers and Manufacture 2-hour DVD by Bane-Clene’s Chemist
Related Carpet Mill Manufacture Information and Articles:
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