Surface Science and Adhesion in Cosmetics. Группа авторов
high-intensity ultrasound and cooling rate on the crystallization behavior of beeswax in edible oils, J. Agric. Food Chem., 62, 10192-10202 (2014).
27. A. J. Martins, M. A. Cerqueira, L. H. Fasolin, R. L. Cunha and A. A. Vicente, Beeswax organogels: influence of gelator concentration and oil type in the gelation process, Food Res. Intl., 84, 170-179 (2016).
28. A. R. Patel, M. Babaahmadi, A. Lesaffer, and K. Dewettick, Rheological profiling of organogels prepared at critical gelling concentrations of natural waxes in a triacylglycerol solvent, J. Agric. Food. Chem., 63, 4862-4869 (2015).
29. H. S. Hwang, M. Singh, J. K. Winkler-Moser, and S. X. Liu, Organogel formation of soybean oil with waxes, J. Am. Oil Chem. Soc., 89, 639–647 (2012).
30. A. I. Blake and A. G. Marangoni, Plant wax crystals display platelet-like morphology, Food Struct., 3, 30-34 (2015).
31. M. Ghosh and S. Bandyopadhyay, Studies on the crystal growth of rice bran wax in a hexane medium, J. Am. Oil Chem. Soc., 82, 229–231 (2005).
32. S. Martini and M. C. Añón, Crystallization of sunflower oil waxes, J. Am. Oil Chem. Soc. 80, 525–532 (2003).
33. H. de Clermont-Gallerande, S. Abidh, A. Lauer, S. Navarro, G. Cuvelier, and J. Delarue, Relations between the sensory properties and fat ingredients of lipsticks, OCL (Oilseeds and fats, Crops and Lipids), 25 (5): D502 (2018).
34. S. Abidh, G. Cuvelier, H. de Clermont-Gallerande and J. Delarue, The role of lipid composition in the sensory and physical properties of lipsticks, J. Am. Oil Chem. Soc.,96, 1143-1152 (2019).
35. Agilent, Basics of measuring the dielectric properties of materials, Application Note http://academy.cba.mit.edu/classes/input_devices/meas.pdf.
36. J. F. Toro-Vazquez, J. A. Morales-Rueda, E. Dibildox-Alvarado, M. Charó-Alonso, M. Alonzo-Macias and M. M. González-Chávez, Thermal and textural properties of organogels developed by candelilla wax in safflower oil, J. Am. Oil Chem. Soc., 84, 989-1000 (2007).
37. C. D. Doan, D. Van de Wall, K. Dewettick and A. R. Patel, Evaluating the oil-gelling properties of natural waxes in rice bran oil: rheological, thermal, and microstructural study, J. Am. Oil Chem. Soc., 92, 801–811 (2015).
38. L. S. Dassanayake, D. R. Kodali, S. Ueno and K. Sato, Crystallization kinetics of organogels prepared by rice bran wax and vegetable oils, J Oleo Sci. 61, 1-9 (2012).
39. Y. Li, S. Han, Y. Lu, and J. Zhang, Influence of asphaltene polarity on crystallization and gelation of waxy oils, Energy & Fuels 32, 1491-1497 (2018).
*Corresponding author: [email protected]
3
UV Curing of Nail Gels by Light Emitting Diode (LED) and Fluorescent (FL) Light Sources
Michael J. Dvorchak* and Melanie L. Clouser
Dvorchak Enterprises LLC, Monroeville, PA, USA
Abstract
The UV nail gel area has seen a significant growth in the cosmetics industry. The significant performance advantage over traditional nail polishes cannot be under-stated. The ability to take a liquid that has been applied to the human nail and cure it within minutes is the major driving force for the development of UV nail gels. Adhesion of the UV nail gel lacquer can be problematic unless the surface free energy and mechanical properties are taken into account. Since the UV nail gels are so highly cross-linked, the removal can also be problematic and new techniques are being developed to reduce the stress on the human nail. Longevity of the UV nail gel finish is also very important but needs to be buffered with the fact that it will be removed within two weeks. Safety of the UV cure lights, (meth) acrylate monomers and oligomers is an issue and needs to be taken into consideration during their use.
Keywords: Ultra violet, free radical, polymerization, photoinitiator, UV nail gel, oligomers, (meth) acrylate monomer, UV cure polyurethane dispersions
3.1 Introduction
The global UV gel market is reported to be worth $59.31 M by the end of 2020. The Compound Annual Growth Rate (CAGR) is estimated to be at 6.6% [1]. With this in mind it is very important to understand what this technology is and how it is used. The UV nail gel market has its roots in the UV-cure industrial coatings and dental market. The need to go away from the closed high-performance UV light sources to the newer low energy UV-A technology was driven by still accomplishing the cure without sacrificing performance. Many new oligomers and photoinitiators (PIs) were developed to meet the need of the UV-A cure in automotive and aero-space areas. These technologies eventually spilled over into the developing UV nail gel market with certain problems and issues. With refined newer formulations, new UV light sources and techniques were developed. This chapter will build the foundation of this unique chemistry and other ways of using the technology for other than human nail beautification.
3.2 UV Cure Chemistry
The use of Ultra Violet (UV)-cure nail polishes had its roots in the industrial coatings market where UV-cure technologies were first introduced for the protection of wood substrates in the office furniture and kitchen cabinet industry to reduce the emissions of formaldehyde as a hazardous air pollutant (HAP). These technologies were based on the uses of oligomers (resins) and monomers in combination with PI to free-radically cure the coating system.
The use of UV radiation provides very fast and controlled generation of highly reactive chemical species which initiate polymerization. Most of the advantages of UV/Electron Beam curing result from a high degree of control over the initiation process.
3.2.1 Initiation Reaction
Photoinitiators (PIs) are used to absorb the light energy and generate the free radicals as shown in Figure 3.1, the initiation step. These initiators are added in the range of 1 to 12 % of the total formulation.
The initiation process occurs only during exposure of the material to UV energy. Since the existing free radicals have very short life spans, all of the propagation reactions also stop when the material is no longer under the UV energy source. Consequently, the final product’s properties are achieved immediately after removal from the UV energy source. Exposure to the UV can range from seconds to minutes.
3.2.2 Propagation Reaction
After initiation, the conversion of the product into a cured solid material proceeds as a normal bulk free radical polymerization and continues to propagate as shown in Figure 3.1, the propagation reaction.