Indigo dyeing process and apparatus and indigo dyed yarns and fabrics made thereby

Abstract

Processes and apparatus are disclosed which substantially eliminate the formation of oxidized indigo dye before and during dye application onto a natural fiber yarn or fabric while allowing the leuco-indigo dye molecule to diffuse fully into the natural fibers of the yarn where it can fix to the fibers prior to oxidation (i.e., exposure of the leuco-dyed yarns to oxygen). Indigo dyed textile products (e.g., dyed cotton yarns that may be twill woven to form a denim fabric) exhibit exceptionally high colorfastness as determined by the AATCC Crock Test.

Description

[0001] Cross References to Related Applications [0002] This application is based on and claims the benefit of priority of US Provisional Application Serial No. 62 / 393,258, filed September 12, 2016, which is incorporated herein by reference in its entirety. technical field [0003] Embodiments disclosed herein generally relate to indigo dyeing processes and apparatus suitable for indigo dyeing natural and regenerated natural fibers such as cotton, wool, rayon, and other biopolymers using low moisture absorption rate coatings such as foams . Also provided are indigo-dyed yarns produced by this process and fabrics formed from such indigo-dyed yarns (e.g., denim fabrics) which exhibit extremely high color fastness (wet and dry). Background technique [0004] Traditional commercial dyeing with indigo is well known. According to a traditional indigo dyeing method, pieces of yarn (with high wet pick-up (wetpick-up) of about 65%-75%) are sequentially dipped in leuco indigo in ...

AI Technical Summary

Problems solved by technology

U.S. Patent Nos. 8,167,958 and 7,913,524 (the entire contents of each patent are expressly incorporated herein by reference) propose a low moisture absorption rate method and require a reduced oxygen presence, thereby further addressing nitrogen media, however, neither patent has specify what level of oxygen contamination they require in each element of the system, and they also do not recommend measuring the actual oxygen content in the system

None of these known systems have demonstrated the success required to replace traditional sheet or rope indigo dyeing

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