NATURAL OILS AND WAXES IN STICK BASES 99 maximum drop point achieved at 4 w/w% carnauba wax content, while further increases in the wax content (towards 5 w/w%) do not result in signifi cant drop point changes (Figure 5). In the case of compression strength measurements, the presence of 1–2 w/w% carnauba or candelilla wax results in a harder consistency. Higher concentrations do not further alter the measured compression strengths (Figure 6). As DSC is an adequate tool to determine the melting point and phase transition param- eters for materials, it was used for the current study (Table II, parts a, b). The results gained by DSC were compared with the softening point and drop point measurements. Furthermore, correlations were examined between the DSC data and the data gained by softening point or drop point determinations. In order to describe the strength of the correlation, the least squares correlation coeffi cient (R2) values were calculated and are reported in Table III. On the basis of the R2 values it is clear that the correlation is strongest between the softening point and the drop point values, with sunfl ower oil as an outlier. These data allow us to conclude that next to DSC measurements, either the drop point determina- tion or the softening point determination gives more reliable data on the thermal properties Table IIa Melting Points (Tm) Determined with DSC for Oily Samples* Type of oil Conc. of oil (w/w%) Tm (°C) Sunfl ower oil 40 59.8 50 58.8 60 57.2 70 55.6 80 55.4 Castor oil 40 62.2 50 61.1 60 61.0 70 58.6 80 58.8 Jojoba oil 40 62.1 50 59.5 60 58.8 70 57.3 80 56.3 Coconut oil 40 60.2 50 60.3 60 59.9 70 58.0 80 54.5 *Composed of 5 w/w% glycerol, 5 w/w% lanolin, and 40–80 w/w% appropriate oil (sunfl ower, castor, jojoba, or coconut) the rest was yellow beeswax.

JOURNAL OF COSMETIC SCIENCE 100 Table IIb Melting Points (Tm) Determined with DSC for Wax Samples * Type of wax Conc. of wax (w/w%) Tm (°C) Carnauba wax 1 57.1 2 57.2 3 60.0 4 58.4 5 67.2 Candelilla wax 1 55.9 2 57.1 3 56.0 4 61.0 5 61.1 *Composed of 5 w/w% glycerol, 5 w/w% lanolin, 60 w/w% sunfl ower oil, and 0–5 w/w% appropriate wax (carnauba or candelilla) the rest was yellow beeswax. Table III Correlation Coeffi cients Determined for Characterization of the Strength of Correlation between Various Thermal Parameters for Oily and Wax Samples Sample Correlating parameters R2 1. Sunfl ower oil Softening point—Drop point 0.9339 Drop point—DSC 0.9825 Softening point—DSC 0.8705 2. Castor oil Softening point—Drop point 0.8373 Drop point—DSC 0.7650 Softening point—DSC 0.4562 3. Jojoba oil Softening point—Drop point 0.9853 Drop point—DSC 0.8049 Softening point—DSC 0.7476 4. Coconut oil Softening point—Drop point 0.9841 Drop point—DSC 0.9287 Softening point—DSC 0.9530 5. Carnauba wax Softening point—Drop point 0.8760 Drop point—DSC 0.5098 Softening point—DSC 0.4300 6. Candelilla wax Softening point—Drop point 0.4167 Drop point—DSC 0.3370 Softening point—DSC 0.2757