78 FORMULATING FOR MILDNESS


Conclusion The growing awareness of environmental aspects increases the focus on the raw materials used in cosmetic products. More and more, ingredients are preferred that are made from natural substances. For surfactants this applies to the hydrophobic and the hydrophilic part. The amino acid surfactants shown in Figures 1 and 2a are an ideal choice as their components - fatty acids and amino acids - are part of nature. The linkage between them is also ‘natural’. Therefore, amino acid surfactants are excellent biodegradable. They are proven to be mild with good foaming properties. For natural cosmetics, cocoyl glutamate is of special interest as it is completely based on renewable raw materials. For some customers in particular propylene glycol- free cocoyl glutamate solutions are ideal candidates for natural cosmetic applications. The N-acyl derivatives of glutamate,


sarcosine and glycine are the most popular amino acid surfactants in Europe. Zschimmer & Schwarz offers surfactants based on these amino acids for all needs of customers. The latest developments are the propylene glycol-free Protelan AG 37 (INCI: Disodium Cocoyl Glutamate, Sodium Cocoyl Glutamate) and Protelan GC-D (INCI: Sodium Cocoyl Glycinate). Both have a very low content of salt and free amino acids (in sum: below 0.2%). AG 37 is approvable for natural cosmetic labels. All Zschimmer & Schwarz products mentioned in this article are preservative-free and also available in RSPO-MB quality. The usage of amino acid surfactants in


combination with other suitable surfactants is a highly attractive way to create viscous cosmetic products without using thickeners: Lowering the pH-value starting from about 7 causes a steady protonation of the anionic carboxylate group(s) of amino acid surfactants. As a result of the neutral carboxylic function the micelle architecture changes completely. By this, viscous aqueous surfactant solutions can be created. This is the case in the particularly attractive pH-range at around 5-6. Besides this, cocoyl glutamates can additionally serve as viscosity reducer and are excellent emulsifiers for cold-processable oil-in-water emulsions. “We still do not know one thousandth of


one percent of what nature has revealed to us” (Albert Einstein). Extrapolated to amino acid surfactants this means: probably there are even more attractive possibilities for them in cosmetic applications which we do not know today.


PC


References 1 Hentrich W, Keppler H, Hintzmann K. Amides,


US Patent 2047069 (1936) 2 Wagner AT, Krohn T. Syndet Cleansing Bars: PERSONAL CARE ASIA PACIFIC


Table 2: Very mild and creamy foaming Body Shampoo Ingredients


INCI PROTELAN GG AMPHOTENSID B 5


Polyquaternium-47 (20%) Perfume Water


Sodium Cocoyl Glycinate, Disodium Cocoyl Glutamate Cocamidopropyl Betaine


Sodium Lauryl Sulfoacetate Sodium Lauryl Sulfoacetate Polyquaternium-47 Parfum (Fragrance) Aqua (Water)


Procedure: 1. Stir to homogeneity until the solution is clear. 2. Adjust the pH value with citric acid to 6.0.


Table 3: Shower Gel for natural cosmetics Phase Ingredients A


Water


B C


Xanthan Gum


ZUTELAN GL 810 ZUTELAN GL 124 Perfume


D PROTELAN AG 37


Sodium Cocoyl Hydrolyzed Wheat Protein


Sodium PCA Glycerin


Lactic acid (80 %) Sodium Benzoate Potassium Sorbate


INCI


Aqua (Water) Xanthan Gum


Caprylyl/Capryl Glucoside Lauryl Glucoside Parfum (Fragrance)


Disodium Cocoyl Glutamate / Sodium Cocoyl Glutamate


Sodium Cocoyl Hydrolyzed Wheat Protein Sodium PCA


Glycerin Lactic Acid


Sodium Benzoate Potassium Sorbate


Procedure: 1. Add B to A and stir to a homogeneous gel. 2. Combine C and stir until it is clear and homogenous. 3. Add all components of D to C in the indicated sequence and stir to homogeneity. 4. Combine AB and CD and stir to homogeneity. 5. Control the pH value and adjust if necessary to 5.3 - 5.5 (original).


The better “Soaps”?, Personal Care Magazine 2019; 13(3): 111 – 114


3 Wagner AT. Sulfate-free Surfactants: What about Sulfonates?, Personal Care Magazine 2018; 12(2): 61 – 65


4 Raykundaliya N, Bordes R, Holmberg K, Wu J, Somasundaran P, Shah DO. The effect on solution properties of replacing a hydrogen atom with a methyl group in a surfactant. Tenside Surfactants Detergents 2015; 52(5): 369 – 374.


5 Jungermann E, Gerecht JF, and Krems IJ, The preparation of Long Chain N-Acylamino Acids. J. Am. Chem. Soc. 1956; 78:172 – 174.


6 Bordes R, Tropsch J, Holmberg K. Role of an amide bond for self-assembly of surfactants. Langmuir 2010, 26 (5): 3077 – 3083.


7 Kaneko A, Sehgal P, Doe H. Interfacial and aggregation properties of aqueous N- dodecanoyl sarcosinate solution at different pH, Colloid Polymer Sci 2012, 290: 323 – 330


8 Preisig N, Schad T, Jacomine L, Bordes R, Stubenrauch C. How promoting and breaking intersurfactant H-bonds impact foam stability, Langmuir 2019, 35: 1499 – 15008


9 Stubenrauch C, Hamann M, Preisig N, Chauhan V, Bordes R. On how hydrogen bonds affect


foam stability, Advances in Colloid and Interface Science 2017, 247: 435 – 443


10 Regan J, Mollica LM, Ananthapadmanabhan KP. A novel glycinate-based body wash, J. Clin. Aesthet Dermatol 2013, 6(6): 23 – 30


11 Zhang Y, Romsted LS, Zhuang L, de Jong S. Simultaneous Determination of Interfacial Molarities of Amide Bonds, Carboxylate Groups, and Water by Chemical Trapping Micelles of Amphiphiles Containing Peptide Bond Models, Langmuir 2013; 29: 534−544


12 Rosen MJ, Zhu BY. Synergism in binary mixtures of surfactants, Journal of Colloid and Interface Science 1984; 99(2): 427 – 434


13 Li Y, Holmberg K, Bordes R. Micellization of true amphoteric surfactants, Journal of Colloid and Interface Science 2013; 411: 47 – 52


14 Wagner AT. Lecture: New hydrotropic surfactants. CESIO World Surfactant Conference 2019.


15 Wagner AT, Bach A, Wehler S. New multifunctional hydrotropic surfactants, SOFW Journal 2016, 142(10): 4 – 8


16 Wagner AT. Powerful surfactants from renewable raw materials, Personal Care Magazine 2016; 9(2): 34 – 36


November 2020


w/w% 50.5


0.5


15.0 5.0 0.4


20.0


1.25 1.2


4.2 1.5 0.3


0.15


w/w% 20.0


15.0 3.0 1.0 0.5


60.5


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