A Diester to Protect Hair from Color Fade and ... - Alluredbooks.com

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Chapter 35 Gao et al.
To test the ability of the diester to protect hair fibers in rinse-off
systems, a shampoo and conditioner were formulated with and without
the diester (see Formulas 1 and 2).
UV Protection with Diester
UVA protection in shampoo: Auburn-colored tresses were treated
with the control and diester shampoo and exposed to 15 equivalent
days of UV exposure (see Figure 35.2). The treated tresses were
visually compared to one another and to a dyed tress that was not
exposed to UV irradiation (Figure 35.2a). The tresses treated with
the control shampoo (Figure 35.2b-c) lost a significant amount of
color while the hair tresses washed with the shampoo containing the
diester (Figure 35.2d-e) showed less color fade. The total color loss
(∆E) of the tresses treated with the shampoos was also assessed after
15 days of UV exposure. Tresses that demonstrated better color protection
had a smaller ∆E. The quantitative color loss data confirms
what the visual assessment illustrates—that the shampoo containing
the diester had a significantly smaller ∆E, and the diester-treated
tress maintained more color. The diester thus demonstrates color
protection with a ∆E of 10.5, compared to the control shampoo
with a ∆E of 12.4, a difference of almost 2 units (see Figure 35.3).
To confirm the correlation between visual inspection of images,
color index measurement and consumer perception, 17 panelists
selected the tresses they thought had the most and least change in
color after tresses were exposed to 15 days of UV. Subjective evaluation
results indicated that 100% of the panelists perceived that
the diester shampoo gave superior color protection on the medium
auburn treated hair (data not shown).
A similar study was performed with the shampoos on hair dyed
with medium brown color. The tresses shown in Figure 35.4 were
treated with the control and diester shampoo. Hair tresses washed
with the diester shampoo (Figure 35.4e-f) showed less color fade
than the control shampoo (Figure 35.4c-d). The left two tresses
were dyed and not exposed to UV (Figure 35.4a-b), to serve as a
reference.
Figure 35.5 shows the quantitative ∆E total color changes of
hair tresses colored medium brown that were treated with both
shampoos and exposed to 15 days of UV exposure. Hair tresses