44 HAIR CARE
in human skin and has been thought to be responsible for ubiquitous moisturisation. The PCA functionality is an excellent humectant, displaying moisture-binding capacity 1.5 times greater than glycerin.8 The PCA functionality can form hydrogen bonds with water, which is essential to healthy hair because it maintains the hydration and moisturisation healthier appearance and texture. Aside from forming hydrogen bonds, the PCA functionality reconstructs powerful ionic bonds. The PCA groups at the polymer chain ends are fully ionised at elevated pH and enhance affinity of the Bis-PCA dimethicone with hair. These ionic bonds are especially useful in preventing further hair damage when the PCA dimethicone is co-formulated with volatile amines and other solubilisers that favour the exchange of volatile amine with the amino group in proteins of the hair. The cumulative strengthening of both hydrogen-bonds and ionic bonds become crucial to supporting the external and internal structure of the keratin protein. When the moisturisation and hydrophobicity of hair is balanced there is improved conditioning.
Efficacy Studies: methods and results
Hair bleaching (in vitro test) l Method The hair tresses used for the in vitro test were virgin black hair and cut to the same weight and length. The general bleaching process used L’Oreal Quick Blue bleaching powder and the developer cream was 40 Volume (12% hydrogen peroxide). Each bleaching processing formula was brushed onto a virgin brown hair tress and wrapped in aluminum foil and allowed to stand at ambient temperature for 2 hours, followed
80 70 60 50 40 30 20 10
Cell 1 Cell 2 Treatment Cell 3
Figure 3: Hair tresses treated with a permanent hair colour red. Initial bleached hair tress prior to colouring (left). Hair tress coloured without additive (middle). Granrepair Powerbond combined with hair colour during treatment (right).
by a rinse with water and blow-dried after each application. The bleaching step was repeated for three to four cycles and evaluated. The hair tresses were not post- treated with conditioners. The amounts used for the bleaching cycle are displayed on Table 1. l Results
It is important to stress that ‘extreme conditions’ were performed in all our testing to compare against a control and against other commercialised products (available upon request). We define “extreme conditions” as procedures that go beyond typical hair salon stylist procedures (such as, 3-4 consecutive cycles with 40V developer, 2 hours bleaching cycles, and no
Box Plot of Number of broken fibers after 2000 strokes grouped by Treatment Repeated Grooming Results
post-treatment conditioner). Performing ‘extreme condition’ testing was necessary to demonstrate that hair salon stylists will deal with customer’s hair that has pre- damaged history (chemical/physical) and will most likely not be virgin hair. Despite these conditions, hair quality results from the functionalised dimethicone treatments are far superior to the control and against other competitive products. The functionalised dimethicone-treated hair displayed highly improved texture and appearance compared to the control after 3 bleaching cycles (Fig 1) and 4 bleaching cycles (Fig 2). The untreated control hair tress appeared damaged, course, and brittle. The texture of the untreated hair was severely dull and frayed. In addition, the treated hair tress displayed improved hair integrity as there was minimal hair loss during wet and dry combing studies compared to the control. When the hair tresses where submitted to 4 bleaching cycles (Fig 2), the functionalised dimethicone displayed the ability to preserve the hair fibre’s physical, mechanical, and surface properties compared to the control. The control hair tress was completely straw-like and unmanageable.
Enhanced colour saturation during colour treatment l Method Colour treatment was performed on pre- bleached hair tresses that had undergone two bleaching cycles (Level 6-7).9
The Mean +
Mean ±SE Mean ±SD Outliners × Extremes
Figure 4: Repeated grooming results after 2000 brush strokes (Number of hair tresses tested is 10 per cell). Cell 1 – Virgin unbleached hair. Cell 2 – Bleached 3 cycles without additive. Cell 3 – Bleached 3 cycles with Granrepair Powerbond.
PERSONAL CARE EUROPE
following hair colouring procedure was followed according to the manufacturer’s guidelines except when an experimental component was added to the manufacturer’s product to demonstrate improved colour saturation attributes of the functionalised dimethicone. Typical procedure outlined requires to mix 1 part of the permanent gel hair colour red (Wella ColorCharm, 7R) with 2 parts of developer (Salon Care 40v/v). Functionalised dimethicone was tested at 0.06 parts relative to the hair colour. This paste is applied onto hair and allowed to remain for a 45-minute interval. The hair was then rinse with water, followed by shampoo and conditioner. l Results Figure 3 displays the result after having colored the hair with a permanent hair colour red (ColourCharm 7R) onto pre- bleached hair (left-tress). It was apparent that the hair tress treated in combination with functionalised dimethicone (right-tress) during the colour procedure had enhanced colour saturation relative to the control. The right hair tress had an enhanced vibrancy of redness. The control (middle-tress) had more of an orange-red saturation compared to the right hair tress. In addition, the hair
September 2018
Number of broken fibers after 2000 strokes
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