EXTRUSION OF COSMETIC PRODUCTS 807 .o• 10 5 ! I 5'5 61:) 65 7b 75 Melting ?oint, OC Figure 5. Melting point as a Junction of penetration 20 I I I I I I I I 5 10 15 20 25 30 35 40 Breaking Strength, (cm) Figure 6. Breaking strength as a Junction of penetration application for some materials but a universal method for all materials has not yet been perfected. FORMULATION The formulations for eyebrow and lipliner pencils are similar in many respects to lipstick and stick eyeshadow. Sagarin (1) notes that eye- brow pencils are formulated similarly to cream-type eyeshadow. Harry (2) has made reference to a black eyebrow formulation which consists primarily of hydrogenated castor oil, hydrogenated cottonseed oil, and lanolin.

898 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 30- & 21 • 15 5 10 15 20 25 % Cocoa Butter Figure 7. Breaking strength as a function of cocoa butter concentration Cosmetic leads are formulated principally from waxes, fats, and oils. The characteristics of these waxes and combination of the waxes can be found in the works of Bennett (3). Beeswax, carnauba, and ceresinc are used primarily for body and strength in the stick. Lanolin, mineral oil, and cocoa butter are good emollients. Japan wax is used because it has certain qualities that improve the sharpening of cosmetic leads. Micro- crystalline wax, carnauba wax, and mineral oil add thixotropic properties to the product. Various blends of these component waxes could give products with qualities of lipsticks and/or cosmetic leads. A typical formulation for cosmetic lead could be the following: Japan wax .......................... 25% Beeswax ............................ 15 Ceresinc ............................. Carnauba ............................ 6 Mineral oil ........................... 3 Lanolin ............................. 20 Cocoa butter ........................ 10 Pigment ............................ 17 A lead of various hardness could be formed by changing the ratio of the lower-melting waxes to the higher-melting waxes.