Trichromatic Vat Dyeing of Cationized Cotton

Abstract

This article deals with cationization of cotton during mercerization and its effects on trichromatic vat dyeing. If cationization is carried out during the after-treatment, regardless of cotton pretreatment, the reaction takes place on the surface and blocks cellulose groups, subsequently resulting in uneven coloration. However, when cationization is carried out with an epihalohydrin during the mercerization process, new cellulose is formed in which the cationic compound is uniformly distributed and trapped between cellulose chains, resulting in uniform coloration after the dyeing process. The reaction time for the process during mercerization is 24 h, thus a more favorable process was researched. Based on electrokinetic analysis, it was found that 5 h was sufficient for the reaction with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC). The cationization of cotton contributed to the processes of vat dyeing. The change in charge upon cationization resulted in very high adsorption of vat-dye anions, indicating that ionic bonding occurred in addition to van der Waals forces. The color depth improved by more than 10 times. It should be emphasized that the colors with higher chroma and targeted color hue, especially in trichromatic dyeing, were obtained on cationized cotton, in contrast to standard cotton fabrics. The color differences obtained under the different light sources indicate the occurrence of metamerism. Considering the color fastness to laundering, vat-dyed cationized fabrics of all colors may be used in hospitals or other environments where high hygiene and oxidative bleaching are required.

Natural Dyeing of Modified Cotton Fabric with Cochineal Dye

“…Additionally, the cationization process significantly lowered COD and BOD values [ 34 ]. Cationization, a modification with amines and quaternary ammonium compounds, results in a change of fiber surface charge, thus reducing or even eliminating the usage of electrolytes in the dyeing process, and is called “salt free” [ 33 , 34 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ]. The cationization agents and techniques have been intensively researched during the last few decades because of this environmental benefit [ 48 , 49 , 50 , 51 , 52 ].…”

“…The cationization agents and techniques have been intensively researched during the last few decades because of this environmental benefit [ 48 , 49 , 50 , 51 , 52 ]. Most common short-chained compounds are epihalohydrins, 2,3-epoxypropyltrimethyl ammonium chloride (EPTAC), and 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC), which give results within 24 h, but time can be reduced to 5 h [ 47 ]. Commercial cationic compounds are usually long-chain compounds with polyammonium bonds.…”

“…Beginning in 2003 [ 53 ] and developed by 2009 [ 51 ], this modification resulted in new cotton cellulose [ 41 , 42 ]. The process was optimized and it was proven that 5 h is sufficient for epihalohydrines, and only 1 h for long-chain commercial compounds [ 47 , 52 ]. The main difference between techniques of pre- or after-treatment and cationization during mercerization is the levelness after the dyeing process.…”

“…When the cationization is performed in the after-treatment, it remains on the surface, helping exhaustion and fixation of the dyestuff and anionic auxiliaries, but this treatment blocks surface groups and the color is not leveled. However, if the cationization is performed during the mercerization process, new cellulose is formed, resulting in permanent modification with all benefits of mercerization and cationization [ 41 , 42 , 47 , 52 ]. Benefits of mercerization are well known—better strength, gloss, and sorption properties, i.e., dye sorption, as a result of conversion of the crystal lattice from cellulose I to cellulose II accompanied by the change in amorphous region of fiber due to different recrystallization [ 41 , 42 , 52 , 54 , 55 , 56 ].…”

Influence of Cotton Cationization on Pigment Layer Characteristics in Digital Printing

“…Change in cellulose crystal lattice occurs and at the same time the cationic compound us evenly distributed and trapped between the cellulose chains, resulting in levelness of colour. There are no published papers related to printing on such modified cotton cellulose, especially ink-jet pigment printing and few papers related to dyeing with direct, acid, natural, vat and reactive dyes within same group of authors [25][26][27][28][29][30]. Therefore, the aim of this research was to investigate and analyse the pigment prints on samples of standard cotton fabric, untreated and modified by the cationization during the mercerization process considering binding of pigment ink and binder itself.…”