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Yasumasa Takao1 Tsuyoshi Asai2 Yasuhiro Shimada3 and Hisakazu Sunada4
1 National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Shimoshidami, Moriyama, Nagoya 463-8560, Japan http://staff.aist.go.jp/yas.takao/indexE.html 2 Sanshin Mining and Manufacturing Co., http://www.sanshin-mica.com/r&d2.html Kamiawashiro, Furikusa, Toei, Kitashitara 449-0213, Japan 3 Nano Seeds Co., http://www.nanoseeds.co.jp/main.htm 2266-99-2 Shimoshidami, Moriyama, Nagoya 463-8561, Japan 4 Meijo Univ., Faculty of Pharmacy, 1-501 Shiogamaguchi , Tempaku-ku, Nagoya 468-8502, Japan
It is well known that mica particles form an important component of cosmetic facial-cakes (powder foundation). However, there is also research on particulate morphology control that is not cost-effective and environment friendly; further, the research on the correlation between mica-particle morphological structures and facial-cake properties evaluated in their practical usage condition is not of any fundamental importance. In this study, we describe the synthesis of a particulate-morphology controlled plate-shaped particles (mica-particle & boron nitride (BN) particle etc.) by spray (or flame) dry (or pyrolysis) containing a nature-origin binder; further, the intercomparative evaluation of practical used mica-particles for cosmetic facial-cake.
It is well known that mica particles (plate-shaped mineral) form an important component of cosmetic facial-cakes (powder foundation). In recent years, consumers have shown a tendency to use products with special features such as a high sun protection factor (SPF), pearlescent, color softening luster, etc. These features are mainly derived from the physical and surface morphology of mica particles. Therefore, cosmetic companies are increasingly involved in applied research on granulate, membranous, needle-like TiO2 (and/or ZnO) used for coating on mica particles; further, granulation of mica particles 1–3. However, there is also research on particulate morphology control that is not cost-effective and environment friendly; further, the research on the correlation between mica-particle morphological structures and facial-cake properties evaluated in their practical usage condition is not of any fundamental importance. In this study, we describe the synthesis of a particulate-morphology controlled plate-shaped particles (mica-particle & boron nitride (BN) particle etc.) by spray (or flame) dry (or pyrolysis) containing a nature-origin binder; further, the intercomparative evaluation of practical used mica-particles for cosmetic facial-cake 3-6.
Typical mica particles used in the manufacture of cosmetic powder foundations were studied (Table 1; ores mined at Aichi, Shimane, Malaysia, China etc. & some synthetic compounds; Sanshin Mining and Manufacturing Co. et al.) 3–5. The size of the droplet and/or mist, and the resultant particulate morphology were controlled by the slurry and spraying condition (dispersion state, heat treatment, temperature/speed, etc.). In this study, we describe the synthesis of a particulate-morphology controlled plate-shaped particles (mica-particle & boron nitride (BN) particle etc.) by spray (or flame) dry (or pyrolysis). The resultant powder was evaluated by FE-SEM, X-ray powder diffraction, particle fundamental characteristics (size distribution, maximum length, aspect ratio, specific surface area, adherability etc.), typical powder bed properties (packing density, flowability, adherability, retention rate of static electrification etc.) and a new powder-bed evaluation method; which realized the practical conditions in which cosmetic facial-cakes (powder foundations) are used. Facial-cake properties were evaluated in their practical usage condition, i.e., optical characteristic (SPF value, pearlescent, color softening luster, etc.) and powder flowability and adherability.
Table 1 Variations in representative mica particles used for its practical application in cosmetic facial-cakes etc.
To systematize the correlation between the morphological structure of mica particles and facial-cake properties, typical mica particles used in practical cosmetic facial-cakes were synthesized and evaluated by the flowability test, etc. Further, a new facial-cake property evaluation method was developed that studied the performance of mica particles in their practical usage conditions 6. Intercomparative evaluation of powder synthesis and fundamental research clarified the correlation between the morphological structure of mica particles and cosmetic facial-cake (powder foundation) properties. Fundamental evaluation of powder properties clarified that sericite (mica), mined in Furikusa (Aichi), exhibited the most well-balanced performance in terms of both the flowability/adherability of the powder and the usage of cosmetic facial-cakes (Figure 1). Both extremes (samples (5)-(8) & (9)-(12)) do not achieve a balance between optical characteristic (SPF value, pearlescent, color softening luster, etc.) and powder flowability/adherability. Further, the new facial-cake property evaluation method was developed that studied the performance of mica particles in their practical usage conditions (esp. powder flowability and adherability). This method also guaranteed these discussions shown in Fig.1.
Figure 1 Examples of particle fundamental characteristics, powder bed properties & cosmetic facial-cake (powder foundation) properties. (this figure shows the correlation between maximum length & facial-cake penetration probability(transmission factor) )
Figure 2 showed examples of the particulate-morphology controlled mica-particle & boron nitride (BN) particle. The use of spray (and/or flame) in the particulate morphology control process was efficient in creating the (2) granular-state TiO2 coating, (3) membranous-state TiO2 coating, (4) needle-shaped state TiO2 coating, (5) granulated powder (solid core or hollow mica-particle). The use of spray (or flame) dry (or pyrolysis) with natural ingredients enabled the control of particulate morphology, as well as made it cost effective and environment friendly. The morphology controlled particles concurrently showed a higher optical characteristic (SPF value, pearlescent, color softening luster, etc.) & powder flowability and adherability, in comparison with basic skin care ingredients, e.g., nylon spherical particles 3–5. The use of spray (and/or flame) in the particulate morphology control process was also efficient in creating the boron nitride (BN), another example in the plate-shaped particles, granulated powder (a typical example of its shape also shown in Figure 2). The morphology controlled particles showed higher thermal-conductive & electric-insulating properties in the shape comparison with basic polymer filler ingredients, e.g., carbon, alumina spherical particles etc. 3–5. The details in these regards are yet to be presented and discussed (patent pending).
Figure 2 Particulate-morphology controlled mica-particles and their processes. (1) Raw particles, (2) Granular-state coating, (3) Membranous-state coating, (4) Needle-shaped state coating, (5) Granulated powder
Conclusion 1. Intercomparative evaluation of powder synthesis and fundamental research clarified the correlation between the morphological structure of mica particles and cosmetic facial-cake (powder foundation) properties. 2. Fundamental evaluation of powder properties clarified that sericite (mica), mined in Furikusa (Aichi), exhibited the most well-balanced performance in terms of both the flowability/adherability of the powder and the usage of cosmetic facial-cakes. 3. A new facial-cake property evaluation method was developed that studied the performance of mica particles in their practical usage conditions (esp. powder flowability and adherability). 4. The use of spray (or flame) dry (or pyrolysis) with natural ingredients enabled the control of particulate morphology, as well as made it cost effective and environment friendly. 5. The morphology controlled particles concurrently showed a higher optical characteristic (SPF value, pearlescent, color softening luster, etc.) & powder flowability and adherability, in comparison with basic skin care ingredients, e.g., nylon spherical particles. 6. The morphology controlled particles showed higher thermal-conductive & electric-insulating properties in the shape comparison with basic polymer filler ingredients, e.g., carbon, alumina spherical particles etc.
Reference
1. Suzuki T: Improvement of transparency and luster of synthetic mica powder for cosmetics. Fragrance J. 2002-4, 45–52, 2002. 2. Tanaka T: Hybrid surface treated pigment and their application for foundation. Fragrance J. 2003-4, 60–66, 2003. 3. Asai T, Takao Y and Suzuki S: Particulate morphology design of mica particle, and its application for cosmetics. Proc. Jpn. Soc. Color Mater. 144–145, 2004. 4. Takao Y and Asai T: Mica-particles prepared by particulate morphology control, and their method. Japanese Patent 2005-219972, 2005. 5. Takao Y and Sando M: Al-system non-oxide spherical powder synthesis by liquefied petroleum gas firing, J. Am. Ceram. Soc. 88, 450–452, 2005. 6. Takao Y, Shimada Y and Sunada H: Micro force sensor, their evaluation method, and their evaluation equipment. Japanese Patent 2006-034558, 2006.