2005 ANNUAL SCIENTIFIC SEMINAR droop, calculated as: [(L - L1) x 100]/(L - Lu)- After measuring initial curl droop for all curls, the pegboard was placed in a high humidity chamber at 22°C and 90% RH. Subsequent curl measurements (Li) were made af1er I, 2, 3, and 5 hours, and the percent curl retention was calculated as given above. RESULTS AND CONCLUSIONS The water-dispersible sulfopolyester, Polyester-5, is known to have a measurable particle size in ethanol/water, and therefore is considered to be a dispersion rather than a solution. The particle size results for all fo-e polymers were very similar (mean diameters from IO to 13 nm), but the concentration of particles was much greater for Polyester-5 compared to the vinyl polymers at the same pol)·mer concentration. This is significant because polymer particles in dispersion release water faster than polymer molecules that are in solution. The \'iscosity results are shown in Figure I. Typically, lower viscosity solutions provide smaller spray droplets. Smaller droplets have a higher surface area to volume ratio, resulting in faster dry times. 2 llle dry times determined by feeling the hair tresses are shown in Figure 2. Dry time determined by OMA shows similar trends. When comparing these results, one needs to consider that the dry time on hair is affected by the sprayed droplet size and the spray pattern (the amount of sprayed solution on the hair), whereas the dry time of the polymer film (OMA method) is independent of these variables. Gloss results show higher gloss for Polyester-5 and VP/Vinylcaprolactam/DMAPA Acrylates compared to the other three polymers. Curl retention results did not show a statistical difference among the five polymers. Fi,·e tresses were tested with each polymer formulation. To ascertain significant differences, more tresses would need to be tested per formulation. Flaking and comb-ability characteristics on hair were also evaluated. No significant problems or dilTerences were noted for flaking and comb-ability among the five polymers. T bl a e 1. air n:ative ff F" o ,·mers or 55% fi VOCU . a1rspra,· Copoh-mer INCi Name Supplier Polyester-5 (formerly Diglycol/ Eastman CHDM/Isophthalates/SIP Copoly.) VP/Vinylcaprolactam/ DMAP A ISP Acrylates Copolymer Octylacrylamide/ Acrylates/ National Butylaminoethvl Methacn-Iate Cop. Starch Acrylates Copolymer# I BASF Acrylatcs Copolymer #2 National Starch Figure 1. Viscosity of Aerosol Concentrates Polyester -5 VP/V1nylcap Oclylacryl Acrylales #1 Acrylates #2 REFERENCES IBroolf,eld LVOV, Spindle #1. 60 rpm 10 15 V1scos1ty, cP 20 Supplied as ... Neutralization ... Pellets Not required 38-42% in ethanol Not required Powder Neutralized 75% (Acidity: 2.5 meq/g ) 35-39% in water Neutralized 100% (Aciditv: -1.0 meq/g ) 50% in water Neutralized 95% (Acidity: 1.5 meq/g) Figure 2. Dry Time - Aerosols Sprayed on Hair Polyester-5 VP/Vinylcap Octylacryl Acrylates #1 Acrylates #2 f-'='-'9-'=�=t'-'-'-'-'=-r='-4" oo oo rn ,� Dry Time, Seconds 1 Kab S. Seo, J. Posey-D0\\1Y, Presented al XJVth International Congress on Rheology, Seoul, Korea, August 22-27, 2004. 2 Phillip M. Cook, S. W. Dobbs, and D.M. Garber, DO Drug & Cosmetic Industry, 160. p 34 (April 1997). 345
346 JOURNAL OF COSMETIC SCIENCE EVALUATION OF FIXATIVES Joseph A. Dallal International Specialty Products, 1361 Alps Road, Wayne, NJ 07470 The previous papers in this section discussed classical and new products, why and how to make them, how to choose and how to use key ingredients, as well as details on what were some of the challenges. Titls last portion will cover how to characterize the final product both as a product and as to its function on the hair. Product Attributes (in the jar) Styling and Fixative products can be characterized by their appearance, application method, container from which they are dispensed, as well as how they perform on the hair in the wet stage and all the stages throughout and after the drying process, like detangling, ease of combing, smoothness, tackiness, stiffness, flexibility, rehydration, response to humidity or dryness, durability, clarity, shine, and removability. Ifwe start by looking from the consumer's viewpoint, we would look at how the product appears in the package and being dispensed from the package. For a product in a clear package, the first measurement would be the color and opacity or clarity. Whether clear or opaque, next might be the texture or flow of the product as the package is tilted at an angle ( or inverted) and possibly poured out or sprayed. At this point the product is also smelled and possibly felt. For aerosols, the first measurements might be the weight of the can, the actual texture and dimensions of the can, the feel or sound as the can is shaken, and then the style of spray followed by the smell and feel on hand, wet through dry. Some of these characteristics may be the foundation for specifications to ensure the product meets the profile and maintains consistency from batch to batch. Quite often, we measure the texture of a product by viscosity. During product development, 2 or 3 shear rates may be employed to take a 'picture' of the response of the product to different situations. For example, to evaluate a product just sitting on the shelf, being poured, or suspending something dense or light, low shear may be used, perhaps 0.5 - 12 rpm. For those products needing to be spread or sprayed, higher shear is used, 30 - 100 rpm. Choosing the wrong shear rate can provide false information. For example, using an inappropriately high shear rate (100 rpm) on a product that shear thins at medium or high shear rate can make a product appear to be thin with low centipoise (cps) readings. However, upon a visual or tactile investigation, the product could be very thick when at rest. The flip side is true when evaluating a product that needs to be thin during application of high shear, like a styling gel in a tube to be spread through the hair, a thickened spray gel, a pump spray, or canned aerosol spray. They need to be evaluated at higher rpm to help predict or quantify how they will respond to the high shear. Of course, testing the final applicator in the lab is critical to choosing the delivery orifice etc. prior to setting specs. Controlling the temperature and choosing the spindle or T-bar and container size can be just as important as setting the rpm for measuring the attribute on which you are focusing. If you consider lotions (water based styling polymer solutions with no thickeners), glazes or serums (water based systems with low levels of thickeners or just soft textures), thick gels (shear thinning clear or opaque), pump and aerosol concentrates, the Brookfield viscometer is still the standard, although others instruments are employed. When reporting the cps, it is often helpful to include the Factor along with the Spindle, speed/rpm, temperature, and timing so it is possible to determine if the cps differences are significant. When it comes to the pastes, muds, glues, sticks, water-waxes, and pomades, evaluations have to move to a Penetrometer type measurement or other bending or smashing methods. For clear systems, both NTU (Nephelometric Turbidity Unit) and %T (percent transmission) are quite often used to quantify the degree of clarity. Low NTU (low haziness) and high %Tare required for clear systems. For colored systems, visual comparisons to color chips or vials of colored solutions are often employed. However, absorption or reflection spectrophotometry (sometimes using the La b system) is used for products as well as packaging. Regardless of color or clarity, odor, before and after the fragrance is added, is important to note, as well as during stability tests. Products we make don't get used the same day they are produced, so microbial or preservative challenges must be evaluated as well as stability at RT, 4°C, Freezerrhaw, and elevated temperatures (accelerated aging) to ensure that the consumer can use the product and achieve the performance expected. What needs to be
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