SM Cocoyl Taurate Powder

Iwata, Hiroshi, et al.Formulas, Ingredients and Production of Cosmetics: Technology of Skin-and Hair-Care Products in Japan, 2013, 113-217.

Facial cleansers and cream soaps mainly consist of potassium salts that originate from lauric, myristic, palmitic, and stearic acids. The melting point along with other characteristics of these potassium salts change according to their fatty acid components which causes difficulties in sustaining uniform viscosity over a wide temperature span. Achieving stable viscosity requires combining multiple potassium salts from distinct fatty acids while analyzing the fatty acid proportions precisely.
Both differential thermal analysis (DTA) and differential scanning calorimetry (DSC) techniques enable stability assessment across various temperature ranges. Stability enhancement depends on higher alcohols like cetanol, glycerin, and PEG along with amphoteric and anionic surfactants such as sodium methyl cocoyl taurate.
Formulation Steps
1. Begin by measuring the amounts of lauric acid, myristic acid, and stearic acid and proceed to heat the mixture to 70°C. (A)
2. Mix potassium hydroxide, sodium citrate, EDTA-2Na, sodium gluconate, glycerin and polyethylene glycol into purified water. (B)
3. Heat the combined A and B mixture until it reaches the temperature of 85°C. (A + B)
4. Blend together 1,2-pentanediol, ethylene glycol distearate, squalane, cetanol, PEG-120 methyl glucose dioleate, cocamide DEA, and sodium methyl cocoyl taurate and stir until you reach a uniform consistency. (A + B + C)
5. The mixture needs to cool to 40°C then measure its pH before adjusting between 9.5 and 10.2 with 10% KOH while adding water if necessary.

Virk, Akashdeep Singh, et al. Available at SSRN 5073745.

In the quest for advanced sulfate-free surfactant systems, this work has thoroughly examined the complex rheological behavior of aqueous mixtures of Cocamidopropyl Betaine (CAPB) and Sodium Methyl Cocoyl Taurate (SMCT) by altering their compositional ratios, pH levels, and ionic strength.
Key Findings
· In the absence of salt, mechanical rheometry revealed that the maximum shear viscosity occurred at a weight ratio of CAPB to SMCT of 1:0.5, which suggested enhanced bridging between the cationic and anionic headgroups.
· Lowering the pH from 5.5 to 4.5 increased the net positive charge on CAPB, enhancing electrostatic interactions with the entirely anionic SMCT, resulting in stronger micellar networks. The addition of salt impacted headgroup repulsions, transitioning the system from separate micelles to elongated, wormlike structures.
· Zero-shear viscosities peaked at specific salt-to-surfactant ratios (R), illustrating the delicate interplay between electrostatic double-layer screening and micellar elongation. Beyond this point, micellar breakdown and partial network disruption led to significant viscosity drops.
· Microrheology through diffusing wave spectroscopy (DWS) affirmed these findings, exhibiting distinct Maxwellian spectra at R ≥ 1, indicative of a breakage-recombination mechanism dominated by reptation. Interestingly, while entanglement and persistence lengths showed little change with increasing ionic strength, contour length was strongly related to zero-shear viscosity.