• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.154-165
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• 2020

To assign the functionality of the regenerated fiber from waste MDF(wMDF) made of pitch pine, we examined the dyeing characteristics of natural dyes, sappan wood as a polychromatic natural red series, monochromatic gardenia as a yellow series, and indigo blue series. For nonemordanting dye, the colors of regenerated fiber dyed by sappan wood and gardenia were reddish yellow (YR) and yellow (Y) series, respectively, and dyeing conditions were appropriate a 30 ~ 50 g/L of dyeing materials at 60 ℃ for 60minutes of dyeing time. We obtained regenerated woody dyed fibers (Re-WDF), YR to the red (R) series by premordanting with Al and Cu mordant for sappan wood and the purplish red (RP) series by Fe premordanting. In the case of gardenia, only Y series colors were developed in nonemordanting dye or all three mordants. Indigo dye produced Re-WDF with greenish yellow (GY) tone at 1%, green (G) tone at 3%, and blue (B) tone at 5% concentration or more. Re-WDF with indigo showed the best light fastness followed by sappan wood and gardenia. In particular, the light fastness of Re-WDF with gardenia was very poor. The light fastness was somewhat improved by premordanting(Fe>Cu>Al) both sappan wood and gardenia dyes.

• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.163-177
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• 2019

This study aims to review the relations between the dyeing conditions (i.e., dye concentration, addition amounts of salt and alkali, and dyeing temperature) and dyeing properties and color fastness to light for identifying the optimal dyeing conditions when dyed regenerated woody fibers were obtained through the defibration of waste medium density fiberboard (MDF) using reactive Red H-E3B (Bis-monochlorotriazine (MCT)/MCT type) and reactive Red RB133% (Bis-MCT/Vinyl sulphone type). The dyeing yield (K/S) obtained using two types of reactive dyes increased as the dye concentration increased by 1-10% (on the weight of fiber (OWF)). In addition, the K/S of H-E3B was higher than that of RB133% irrespective of the dye concentration. The color difference of H-E3B after ultraviolet (UV) radiation was lower than that of RB133%, denoting good resistance to discoloration by UV. As the amount of sodium sulfate increased, the color difference and K/S also increased, and the adequate salt content was determined to be 50-70 g/L. Further, the color difference and K/S significantly increased only the addition of 2 g/L of sodium carbonate; however, almost no difference was observed when more than 2 g/L of sodium carbonate was added. The addition amount of sodium carbonate was adequate 5-10 g/L to dyeing the fiber and the pH at this addition level was 10. The dyeing yield of H-E3B increased when the dyeing temperature increased; however, it subsequently decreased after the dyeing temperature became $80^{\circ}C$. The dyeing yield of RB133% was almost the same up to $60-70^{\circ}C$ but declined subsequently. Thus, the adequate temperatures were $80^{\circ}C$ and $60^{\circ}C$ for H-E3B and RB133%, respectively. If the waste MDF woody fiber was dyed under the aforementioned optimal conditions, dyed regenerated woody fiber can be obtained having the following colors: 1.5 to 2.0R with the H-E3B dye and 9.6 to 10.0 PR with RB133%.