246 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS tiers or water solubilizers. The use of tetrahydrofurfuryl acetate as a bromo solvent is covered by patents. As staining colors the halogenated fluoresceins are used: Color Chemical Formula Stain D&C Orange #5 Dibromfluorescein Orange red D&C Red #21 Tetrabromfluorescein Red D&C Red #27 Tetrabromtetrachlorfluorescein Blue red There are several other colors of this general structure that are certified. Their use has been limited. General practice is to use 3 parts bromo acids and 12 parts lake color to 100 parts base. Variation in consistency and melting point in different shades of lipstick is quite often encountered even though the same base and color con- centration are used. This is due to differences in the oil absorption of the various colors. Taking an arbitrary oil absorption as indicated by flow characteristics as a value of 0, we have charted the colors as follows, giving a negative value to those with a lesser amount of oil absorption and a posi- tive value to those with a greater amount. D&C Orange if4 ............................................. - 2.'0 D&C Red #9 ................................................ - 3:0 D&C Red #35 ............................................... - 0.5 D&C Red #21 ................. A1. salt ........................ '15.0 D&C Red #11 ............................................... 3.5 D&C Red #13 ............................................... - 1.0 D&C Red #19 ................. A1. salt ........................ 1.0 D&C Red #7 ................................................ 0.5 D&C Red #34 ................. Resinated Ca. salt .............. 12.0 Titanium Dioxide ............................................ - 4.0 D&C Red #21 ............................................... •-- 2.5 D&C Orange #5 .............................................. - 1.5 D&C Red #27 ............................................... - 2.0 The weighted average of oil absorption for each formula in a series of shades should be as uniform as possible. The differences in oil absorption are ap- parent where melting points are taken by the capillary tube method. A lipstick made with a colorless base with 65øC. m.p. might have a re.p, of 66 ø in a shade high in titanium dioxide and 72øC. in a shade high in D&C Red//34. In manufacturing lipsticks, the colors are mixed with part of the oil in change can mixer A, then passed through a three-roller mill B. The color and oil are ground a sufficient number of times to achieve a color distribu- tion of 7 or better on a grind gauge. The color in oil is heated to 70øC. in kettle C. The balance of materials is heated to 90 ø in kettle D. The con- tents of D is strained through a 2$0-mesh stainless steel screen E into C with constant agitation in C. After several hours' stirring, samples are drawn off for control tests. Any adjustment in shade is made by using color bases

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