LIPSTICKS--FORMULATION, MANUFACTURE, AND ANALYSIS 247 VACUUM o•T•o•uA•. To Figure 1. of the same concentration of color and bromo acid as are used in the lip- stick. If satisfactory, the lipstick is drawn off from C through a 200-mesh stainless steel screen F ready to mold or slabbed for future molding. Prior to molding the material is melted with slow agitation in melting kettle G to remove entrapped air. A vacuum in a closed melting kettle will greatly aid in eliminating entrapped air. Temperature control is important throughout the processing, with care being taken to avoid excessive tem- peratures in the kettle. CONTROL METI4ODS Control in manufacturing lipsticks is greatly assisted by a thorough con- trol of incoming raw materials. Methods for raw material control are covered by the Toilet Goods Association, American Oil Chemists Society, and Association of Official Agricultural Chemists. Melting points are taken by the capillary tube method. The results secured are relative but should be consistent for the same color formulation. This method depends on "flow" and differences in oil absorption of the various coloring matters will give different melting points. A substantial difference in melting point for a given shade indicates some error in the formula or in the raw mate- rials. Heat resistance for a minimum period of 24 hours is a much better guide of heat stability. Lipstick A is inserted in case B and passed through bar C, to hold it in vertical position. It is kept in a constant temperature box at a temperature of 55øC. or any other desired temperature for 24 hours. Any tendency to droop or distort is noted. The stick should not show any change after 24 hours at the desired temperature. Hardness is tested by pouring lipstick into a ring 2 in. inside diameter and 1 in. deep. It is allowed to stand for 12 hours in a constant temperature box at 20øC. Tests are taken with a penetrometer (A.S.T.M.). Five

248 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figure 2.--Heat Test: A = I.ipstick, B -- Lip- stick Holder, and C -- Stationary Block. c k4 Figure &--Rupture Test: A = Lipstick, B = Lipstick Case, C = Stationary Block, E = Movable Block, D = Guide Rack, and M -- Micro Switch. readings are taken. The average is calculated and compared with stand- ard. High humidity tests are run by putting filled lipstick containers in a desiccator containing water. The desiccator is kept in a constant tempera- ture box at a temperature of 45øC. and examined periodically. The stick is examined for sweating and bleeding. The container is examined for discoloration or corrosion. RUPTURE TESTS Lipstick A is put in holder B and inserted into stationary block C and through movable block E. Block E rides on guide rods D. Weights are put at F, with a 30-second interval between each addition of weight. When stick ruptures, E moves on guide rods D to reach microswitch M, which lights up bulb. Weights plus weight of E is pressure required for rupture. Shade and intensity of stain are best judged on the skin by comparison with standard. Skin tone and undertone are also checked on the skin. Mass tone is judged by comparison with standard. Color content is determined by extraction with isopropyl ether. The ether solution is washed several times with 0.1 N aqueous sodium hydroxide. This will extract the bromo acids. The sodium hydroxide extraction is precipitated with 1 N hydrochloric acid. The reconverted bromo acids are washed several times with the hydrochloric acid. They are dried at 80øC. and weighed. The bromo acid content of any bromo acid lakes will also be extracted under these conditions. The residue from the ether ex- traction is washed several times with isopropyl ether. It is air dried in a hood and weighed to determine insoluble coloring matter. /lcknowledgment: is made with thanks to Harry Holtzman of the Ans- bacher Seigle Corp. for his assistance in the work on oil absorption of colors.