Process Description
The term "toiletries" refers to the group of products used for personal hygiene. Included in this category are skin lotions, shampoos, cosmetics, shaving cream, etc.
Skin Lotions and Creams: Emulsions of oil-in-water (o/w) or water-in-oil (w/o) are commonly used as the base for many of the lotions and creams to affect their emollient qualities. O/w emulsions produce a cooling effect on application to the skin owing to water evaporation. Cold-cream emulsions are w/o, the emulsifier is sodium cerotate formed by reaction of borax and free cerotic acid in beeswax. Vanishing cream can be considered to be an emulsion of a free fatty acid (usually stearic acid) in a non-alkaline medium. Lotions are identical to those of an emollient cream, but they are present in lower concentrations.
Deodorants and Antiperspirants: Deodorant and antiperspirant products exist in many different forms including creams, gels, lotions, powders, soaps, and sticks. Aluminum chloride which was once the most popular ingredient, may cause fabric damage and skin irritation as a result of its low pH. Other products have been developed as a result including aluminum chlorohydroxide (ACH).
Sunscreens: There are two types of sunscreens: the physical type which are opaque to block and scatter light (these generally contain titanium dioxide or zinc oxide) and the chemical type, which absorb UV light. Different chemicals will absorb different spectrum. Some of the most commonly used include anthranilates, cinnamates, p-aminobenzoic acid (PABA) and its ester derivatives.
Make-up and Cosmetics: Make-up and cosmetics combines chemistry, physics, and biology to produce products with different properties to enable easy application, lasting performance, non-streaking color, etc. Color pigments and dyes are generally mixed with a base of zinc oxide or a mixture of aluminum hydroxide and barium sulfate. White colorants include titanium dioxide, zinc oxide and talcum. Face powder is a blend of white pigments and inorganic colorants, principally iron oxide. Lipstick is a solid fatty base product containing dissolved and suspended colorant materials. The colorants used in lipsticks are oil-soluble dyes of the eosin group. Mascara ingredients are strictly limited by law because of the proximity of these products to the eye. Colorants are limited to natural dyes and inorganic and carbon pigments. Eye shadows are made using the colors of carbon black, ultramarine blue, and the various yellows, browns, and reds of the iron oxide pigments. Eye shadow base generally consists of beeswax, ozokerite, mineral oil, lanolin and petrolatum. Nail polish is made from a resin (nitro-cellulose), plasticizer, low boiling point alcohols as solvents and pigment. Nail polish remover is made from various solvents, acetone being especially common. Cuticle softeners and removers generally contain a dilute solution of alkali with some glycerol.
Hair Products: Shampoos are made from a primary detergent with color and perfume. Low pH (4.0 to 6.0) has proven to cause the hair cuticle to tighten, giving the hair luster because light is more efficiently reflected. Hair also shows its highest strength and resiliency at this pH range. Combinations of triethanolamine and sodium and ammonium lauryl sulfates with amine oxides can be adjusted to low pH with good stability. Depilatories to remove unwanted hair are a strongly alkaline medium with calcium thioglycolate. The pH of these solutions is approximately 12.3.
Bath Oils: There are two types of bath oils: those that spread or float on top of the water, and those that disperse within the water. The first type contains small amounts of an oil-soluble surfactant with one or more hydrophobic components such as vegetable oils, lanolin, mink oil, or low fatty alcohols. The dispersible types are oil-in-water dispersion; as the water evaporates, the hydrophobic residue remains. Foaming bath oils and foam baths are based on surfactants, either liquid or powder, which are blended with color, perfume, and foam stabilizers.
Shaving Cream: Lathering shaving creams are soft soaps made from potassium hydroxide salts and fatty acids. Brushless creams are similar to vanishing creams containing an excess of free fatty acids (usually stearic acid) emulsified into a non-alkaline base of suitable viscosity or consistency. Gel shaving creams are emollient gels that are soap based and contain a volatile solvent such as pentane. Dispensed as a soft gel from a pressurized container, the solvent is released, expanding as it volatizes and forms foam.
Signet Applications
Mixing: Batching systems are common in many of the larger facilities. These applications include batching of components into the mix tanks making each formulation, and also end product batching into bulk tanker trucks.
Water Treatment: Deionized water is used in virtually all toiletry plants for most of their liquid preparations. The DI water system has many monitoring points for flow, pH and conductivity. These monitors ensure water cleanliness, proper pH to ensure product performance, and flow to monitor the performance of the filters and resin beds.
Formula Adjustments: Many processes must be adjusted for proper pH during the formulation of the product.The effectiveness of shampoos, deodorants, hair depilatories and other toiletries is determined by the pH. The acceptance of dye in make-up may also be affected by pH.
Waste Neutralization and Water Treatment: The waste treatment area for the toiletries manufacturing plant must handle the many different pigments used for coloring cosmetics including those based on iron oxides. The iron must be treated and removed before any wash streams could be discharged to the city. Other metals such as chrome for the glitter sometimes used in eye shadow and titanium dioxide used as a whitener in face powders must also be treated using standard heavy metal removal treatment techniques. Acid and bases are also used throughout the plant for pH adjustment. Waste streams from these lines and tanks must also be neutralized. The waste treatment area may contain separate pH controls for the metal precipitation, or separate chrome treatment utilizing both pH and ORP control. Final effluent flow monitoring is also an important measurement this industry. |
