Compare meadowfoam seed oil (M) as a pigment dispersant for lipsticks versus common dispersants castor oil (C) and octyldodecanol (O).
Dispersing agents are essential components of lipsticks due to their ability to wet pigment particles, reduce the agglomerates, and prevent re-agglomeration by stabilizing pigment particles.
Nine dispersions were made using C, O, and M and Red 7 Lake with 20, 30 and 40% solid content. Particle size, viscosity, spreadability, wetting, and color were measured. Then, lipsticks with 30% color were formulated with C (L1), O (L2), and M (L3). Lipsticks were tested for hardness, pay‐off, friction, rheology, color, and stability for 4 weeks at 25, 40 and 45°C.
All dispersions had a small particle size (<10 μm). C dispersions were more viscous, stickier, and harder to spread, and L1 was the hardest and most elastic. L2 was the softest, L3 was in between L1 and L2. Friction, pay-off, color, and stability of L3 were similar to L1.
Meadowfoam seed oil proved to be a viable dispersing agent, forming dispersions and lipsticks qualitatively and quantitatively similar to C and O.
A consumer study would be complimentary.
We thank Natural Plant Products for funding.
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