JOURNAL OF COSMETIC SCIENCE 94 further confi rmed the SPE’s plasticization effect. For the SiAc/SPE (7:3) blend, DSC in- dicates a melting transition with onset of 43°C and peak at 68°C, broader and lower than that of neat silicone acrylate. Film properties of compatible blends of “Hard” silicone acrylate and “Soft” SPE may be tuned by the ratio of “Hard” to “Soft.” Figure 3 shows fi lm hardness and tack of silicone acrylate and “Bis-IsobutylPEG/PPG-10/7 Dimethicone Copolymer” blends at different ratios. Film hardness was studied by pendulum fi lm hardness test, where a higher count is correlated to a harder fi lm. Film tackiness was measured by texture analyzer. A higher maximum tack force is generally correlated to a more tacky fi lm. Figure 3A suggests a correlation between softer fi lm and higher fraction of “Soft” SPE in the blends. Within the “Soft” to “Hard” ratio studied, fi lm becomes tackier with increasing the fraction of SPE (Figure 3B). Cracking and fl exibility of color cosmetic fi lms containing silicone acrylate/SPE blends were further investigated. For a formulation using silicone acrylate as the sole polymeric nonvolatile, dried fi lm exhibited visible cracks (data not shown). On the other hand, the formulation with a combination of nonvolatile silicone acrylate and “Bis-Isobutyl PEG/ PPG-10/7/Dimethicone Copolymer” (an SPE) at 7:3 wt ratio yielded a dry fi lm exhibit- ing no observable cracks (data not shown). Stretching test was conducted by drying these prototype formulations on a fl exible rubber band. After the rubber band was elongated, fi lms were assessed for cracking. Figure 4 showed that fi lms with an adequate fraction of Figure 2. Viscoelastic profi le of “Soft” + “Hard” blends. (A) Temperature sweep elastic modulus measurement on several blends of silicone acrylate and SPE with different ratios. (B) Damping factors of related blends. Figure 3. Film hardness and tack. (A) Pendulum fi lm hardness measurement on blends of silicone acrylate (“Hard”) and SPE (“Soft”) at different “Hard” to “Soft” ratios. (B) Related fi lms’ maximum tack force measured by texture analyzer.

LONG-WEAR SEBUM-RESISTANT COSMETICS 95 SPE did not crack under the test condition, suggesting more fl exible than fi lms’ based on lower fractions of SPE. Sebum/oil abrasion test was conducted to understand a makeup fi lm’s rub-off resistance in the present of sebum (3). Figure 5A shows compositions of anhydrous makeup proto- types containing blends of silicone acrylate and SPE at different “Hard” to “Soft” ratios. After dried on collagen, cosmetic fi lms were subjected to abrasion test. Figure 5B shows a digital camera image of both abrasion cloths and cosmetic fi lms after given 100 rubs. The top row shows, in duplicate, abrasion cloth and cosmetic fi lms after abrasion without artifi cial sebum treatment. The bottom row shows, in duplicate, abrasion cloths and cos- metic fi lms after abrasion with sebum pretreatment. Figure 5C shows abrasion clothes’ color increase after 100 rubs as measured by colorimeter. Figure 5D shows makeup fi lms’ color loss as measured by colorimeter. With the understanding that sebum is a culprit leading to poor wear performance of color cosmetics, abrasion testing of the substrate pretreated with artifi cial sebum oil confi rmed more color transfer than without sebum. Importantly, we found ideal “Hard” to “Soft” ratios may exist for improved performance. When higher levels of the SPE (soft component) were incorporated, considerable rub-off and transfer were observed, especially in the presence of sebum. On the other end, at very Figure 4. Stretching test showing fi lm fl exibility. Images were taken before and after stretching test, showing cracking of fi lms made with silicone acrylate and SPE blends at different ratios. Figure 5. Sebum abrasion test. (A) Anhydrous makeup prototypes containing a silicone acrylate and a SPE at different ratios. (B) A digital camera image of both abrasion cloths and cosmetic fi lms (on collagen) after given 100 rubs, with or without artifi cial sebum pretreatment. (C) Abrasion clothes’ color increase after 100 rubs. (D) Makeup fi lms’ color loss after 100 rubs.