Impact of Natural Dyes Cochineal (Dactylopius coccus) and airampo (Opuntia soehrensii) on the Physico-Mechanical Properties and Colorfastness of Alpaca (Vicugna pacos) Yarns
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Date
2026-03-12
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Natural Fibers of Taylor & Francis
Abstract
The effect of dyeing with natural colorants on the physico-mechanical properties, colorimetric parameters, hydrophobicity, and color fastness of alpaca threads (Vicugna pacos) was investigated. Two dyes from the Andes were evaluated: cochineal (Dactylopius coccus) and airampo (Opuntia soehrensii), using a post-mordanting method with sodium sulfate (Na2SO4), oxalic acid (C2H2O4), and potassium alum (KAl(SO4)2·12 H2O). The analysis of the results showed that the dyeing treatments did not significantly affect the elongation (51–65%), maximum strength (1.64–1.94 N), or tenacity (0.93–1.10 MPa) of the threads. Regarding colorimetry, cochineal produced intense red shades (a* = 34.95) and the highest saturation (C*) of up to 40.29. Meanwhile, airampo generated warm, bright yellow tones (L*) up to 70.19. A critical finding was the low wash fastness, with ratings of 1 to 2 on the grayscale. However, the rub fastness ranged from moderate to good (2 to 4–5). Dyeing with pure cochineal increased the hydrophobicity of the thread, reaching a contact angle of 97.22°. These results indicate that, although the dyes offer a rich color range without compromising the fiber, it is essential to optimize the process to improve color fixation before commercialization.
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Keywords
Vicugna pacos, Sustainable dyeing, Cochineal, Airampo, Color fastness, Mechanical properties
