DOI QR코드

DOI QR Code

Phase Behavior Study of Fatty Acid Potassium Cream Soaps

지방산 칼륨 Cream Soaps 의 상거동 연구

  • Received : 2022.03.15
  • Accepted : 2022.03.28
  • Published : 2022.03.30

Abstract

The potassium cream soap with fatty acid called cleaning foam has a crystal gel structure, and unlike an emulsion system, it is weak to shear stress and shows characteristics that are easily separated under high temperature storage conditions. The crystal gel structure of cleansing foams is significantly influenced by the nature and proportion of fatty acids, degree of neutralization, and the nature and proportion of polyols. In order to investigate the effect of these parameters on the crystal gel structure, a ternary system consisting of water/KOH/fatty acid was investigated in this study. The investigation of differential scanning calorimeter (DSC) revealed that the eutectic point was found at the ratio of myristic acid (MA) : stearic acid (SA) = 3 : 1 and ternary systems were the most stable at the eutectic point. However, the increase in fatty acid content had little effect on stability. On the basis of viscosity and polarized optical microscopy (POM) measurements, the optimum degree of neutralization was found to be about 75%. The system was stable when the melting point (Tm) of the ternary system was higher than the storage temperature and the crystal phase was transferred to lamellar gel phase, but the increase in fatty acid content had little effect on stability. The addition of polyols to the ternary system played an important role in changing the Tm and causing phase transition. The structure of the cleansing foams were confirmed through cryogenic scanning electron microscope (Cryo-SEM), small and wide angle X-ray scattering (SAXS and WAXS) analysis. Since butylene glycol (BG), propylene glycol (PG), and dipropylene glycol (DPG) lowered the Tm and hindered the lamellar gel formation, they were unsuitable for the formation of stable cleansing foam. In contrast, glycerin, PEG-400, and sorbitol increased the Tm, and facilitated the formation of lamellar gel phase, which led to a stable ternary system. Glycerin was found to be the most optimal agent to prepare a cleansing foam with enhanced stability.

Cleansing foam이라 불리는 지방산 칼륨 cream soap은 crystal gel 구조로 이루어져 있어 유화계와는 달리 전단응력에 약하며 고온의 보관조건에서 쉽게 분리되는 특성을 보여준다. Crystal gel 구조는 지방산의 종류 및 비율, 중화도, polyol의 종류와 사용량에 따라 크게 영향을 받는다. Crystal gel 구조에 미치는 이들의 영향을 조사하기 위해 water/potassium hydroxide (KOH)/fatty acid ternary system에서 실험을 실시하였다. Differential scanning calorimeter (DSC) 측정 결과 myristic acid (MA) : stearic acid (SA) = 3 : 1 비율에서 공융점(eutectic point)를 갖고 이 혼합비가 가장 안전한 삼성분계(ternary system)를 만든다는 것을 발견했다. 점도 측정과 편광현미경 (POM) 관찰 결과 중화도는 75% 부근이 최적이라고 판단된다. 삼성분계의 melting point (Tm)이 보관온도보다 높을 때, 그리고 crystal phase가 lamellar gel phase로 상 전이가 일어날 때 안정하나 지방산 함량의 증가는 안정성에 거의 영향을 미치지 않는다. 삼성분계에 polyol의 첨가는 Tm을 변화시키고 상전이를 일으키는데 중요한 역할을 한다. 클렌징폼의 구조는 저온 주사전자현미경 (Cryo-SEM), 소각 및 광각 X-선 산란 (SAXS, WAXS) 분석으로 규명하였다. Butylene glycol (BG), propylene glycol (PG), dipropylene glycol (DPG)은 Tm을 낮추어주며 lamellar gel phase 형성을 어렵게 하는 반면 glycerin, PEG-400, sorbitol은 Tm을 상승시키고 lamellar gel phase 형성을 용이하게 하며 안정한 삼성분계를 만든다.

Keywords

References

  1. H. Watanabe and K. Oinuma, The formulation and production of cleansing foam, Fragrance Journal, 8, 77 (1993).
  2. V. Luzzati, H. Mustacchi, and A. Skoulios, The structure of the liquid- crystal phases of some soap + water systems, Discuss. Faraday Soc., 25, 43 (1958). https://doi.org/10.1039/DF9582500043
  3. S. Zhu, P. D. A. Pudney, M. Heppenstall-Butter, M. F. Butler, D. Ferdinando, and M. Kirkand, Interaction of the acid soap of triethanolamine stearate and stearic acid with water, J. Phys. Chem. B, 111(5), 1016 (2007). https://doi.org/10.1021/jp0659047
  4. I. Murotani and F. Harusawa, Technological progress in formulation and manufacture of cleansing foam, Fragrance Journal, 7, 32 (1986).
  5. C. Labes-carrier, J. P. Dumas, B. Mendiboure, and J. Lachaise, DSC as a tool to predict emulsion stability, J. Dispers. Sci. Technol., 16(7), 607 (1995). https://doi.org/10.1080/01932699508943709
  6. D. Clausse, Thermal behaviour of emulsion studied by differential scanning calorimetry, J. Therm. Anal. Calorim., 51(1), 191 (1998). https://doi.org/10.1007/BF02719021
  7. M. S. Yoon, Y. B. Chung, and K. Han, A study of gel structure in the nonionic surfactant / cetostearyl alcohol / water ternary systems by differential scanning calorimeter, J. Dispers. Sci. Technol., 20(7), 1695 (1999). https://doi.org/10.1080/01932699908943885
  8. K. W. Kim, J. H. Kim, Y. D. Yun, H. J. Ahn, B. S. Min, N. H. Kim, S. G. Rah, H. Y. Kim, C. S. Lee, I. D. Seo, W. W. Lee, H. J. Choi, and K. S. Jin, Small-angle X-ray scattering beamline BL4C SAXS at pohang light source II, Biodesign, 5(1), 24 (2017)
  9. J. W. Mcbain and W. C. Sierichs, The solubility of sodium and potassium soaps and the phase diagrams of aqueous potassium, soaps, J. Am. Oil Chem. Soc., 25, 221 (1948). https://doi.org/10.1007/BF02645899
  10. A. Sari, Eutectic mixtures of some fatty acids for low temperature solar heating applications: Thermal properties and thermal relability, Appl. Therm. Eng., 25(14-15), 2100 (2005). https://doi.org/10.1016/j.applthermaleng.2005.01.010
  11. P. Zhao, Q. Yue, H. He, B. Gao, Y. Wang, and Q. Li, Study on phase diagram of fatty acids mixtures to determine eutectic temperatures and the corresponding mixing proportions, Appl. Energy, 115, 483 (2014). https://doi.org/10.1016/j.apenergy.2013.10.048
  12. S. Tomomasa, F. Harusawa, and Y. Machida, Phase Transitions of the potassium stearate-water-polyol systems, J. Jpn. Oil Chem. Soc., 36(12), 938 (1987). https://doi.org/10.5650/jos1956.36.938
  13. H. Sagitani, Stability conditions and mechanism of cream soaps: Role of glycerol, J. Oleo Sci., 63(4), 365 (2014). https://doi.org/10.5650/jos.ess13174
  14. H. Sagitani and M. Komoriya, Stability conditions and mechanism of cream soaps: Effect of polyols, J. Oleo Sci., 64(8), 809 (2015). https://doi.org/10.5650/jos.ess14292
  15. S. E. Friberg and Y. Liang, Phases equilibria in the glycerol-aerosol OT systems with decanol or hydrocarbon, Surfactant Science Series, 24, 103 (1987).
  16. S. Borsacchi, M. Ambrosi, P. L. Nostro, and M. Geppi, Understanding the properties of the coagel and gel phases: A 1H and 13C NMR study of amphiphilic ascorbic acid derivatives, J. Phys. Chem. B., 114(48), 15872 (2010). https://doi.org/10.1021/jp107324e
  17. P. Tandon, G. Forster, R. Neubert, and S. Wartewig, Phase transitions in oleic acid as studied by X-ray diffraction and FT-raman spectroscopy, J. Mol. Struc., 524(1-3), 201 (2000). https://doi.org/10.1016/S0022-2860(00)00378-1
  18. R. Nadarajan and R. Ismail, Performance and microstructural study on soap using different fatty acid and cations, J. Surfactants Deterg., 14(4), 463 (2011). https://doi.org/10.1007/s11743-011-1251-x