Emulsion-base components

The Cosmetic, Toiletry and Fragrance Association s International Cosmetic Ingredient Dictionary provides an exhaustive listing of the variety of emulsion-base components, particularly the oil phase... 

There are two categories of white oils technical white oils and medicinal white oils. The technical white oils, which are already highly dearomatized, are used for specialized lubricants, particularly in the textile industry, and also as components in cosmetics, as plasticizers in the rubber or plastics industries, or as emulsion bases for certain pulverized agriculture products. The medicinal white oils, whose dearomatization is pushed further still, are used in pharmaceuticals, or in the food industry, wherever residual oils might be in contact with food. 

Quarpel is an important combination of fluorochemical finish and resin-based extender developed by the U.S. Army Natick Laboratories for military use. This finish typicaUy contains 4—6 wt % commercial fluorochemical emulsion, 4—6 wt % resin-based repeUent emulsion, 0.1 wt % acetic acid, and 5 wt % isopropyl alcohol. If necessary, the formulation includes a catalyst to cross-link the resin-based component. Quarpel specifications demand exceUent initial water and oU repeUency and exceUent durabUity to washing and dry cleaning. 

Hydroxyalkyl lignin derivatives were crosslinked with diisocyanates or with melamine in both solvent and aqueous emulsion-based adhesive formulations for wood products (51) (Figure 7). Adhesive performance was found to be related to component solubility and compatibility (51), The use of kraft lignin in aqueous alkali and that of lignin sulfonates in water has been explored in combination with emulsifiable diisocyanates (52) in wood adhesives. Satisfactory strength properties were reported. 

Surfactant adsorption is an excellent method of tailoring microparticle surface chemistry because the surfactant can be designed to stabilize the forming particle surface during an emulsion-based fabrication procedure. Surface chemistry analysis is established as a vital component of the microparticle design process because it allows the amount of surfactant adsorbing to a surface to be quantified. 

The nanocomplexes formed between proteins and polysaccharides, and emulsion-based systems have been examined for their ability to protect and deliver a variety of food components. Cross-linking biopolymers has been used to improve microcapsule stability. Glutaraldehyde is an effective cross-linking agent but is not allowed in food. An alternative to glutaraldehyde that has been examined is tannin. 

McClements, D.J., Decker, E. A., and Weiss, J. (2007). Emulsion-based delivery systems for lipophilic bioactive components. J. Food Sci. 72(8), R109-R124. 

One can rationalize a need for small rubber inclusions in some of the newer approaches to waterborne and high solids epoxy coating systems. Water-thinned epoxy coating compositions are described (48) where the two-component system consists of a nitrile rubber modified epoxy resin in the epoxide component and a styrene/ butadiene/methylmethacrylate latex modifier for an emulsion-based polyamide hardener component. Showing improved adhesion, impact and water resistance, the paint has good wetting characteristics and can be formulated to a high solids content at low viscosity. 

McClements, D. J. Li, Y., Structured emulsion-based delivery systems Controlling the digestion and release of lipophilic food components. Advances in Colloid and Interface Science (2010) 159, 213-228. 

The rheological data are given in Table 1. The second column of the table is the evaporation state of the oil in mass pereentage lost. The third column is the assessment of the stability of the emulsion based on both visual appearance and rheological properties. The power law constants, k and n, are given next. These are parameters from the Ostwald— de Waele equation which describes the Newtonian (or non-Newtonian) characteristics of the material. The viscosity of the emulsion is next and in column 7, the complex modulus which is the vector sum of the viscosity and elasticity. Column 8 lists the elasticity modulus and column 9, the viscosity modulus. In column 10, the isolated, low-shear viscosity is given. This is the viscosity of emulsion at very low shear rate. In column 9, the tan 5, the ratio of the viscosity to the elasticity component, is given. Finally, the water content of the emulsion is presented. 

Originally the adhesive system consisted of an aqueous poly(vinyl alcohol) solution with an isocyanate cross-linker. At this stage the common name was Aqueous Polymer Isocyanate (API) [3]. Further developments including use of different types of polymer emulsions, like poly(vinyl alcohol) (PVA), ethyl(vinyl acetate) (EVAc), styrene butadiene rubber (SBR) or acrylic-styrene (AcSt) emulsion, led to adhesives systems with improved performance, hence today the common abbreviation is EPI [4, 8]. The isocyanate cross-linking agent has also been further developed to improve the compatibility and the reactivity with the water-based component, thus several different types are now available for use in EPI adhesives. 

EPI adhesives are two-component systems. In the following the emulsion/polymer based component (the adhesive component) and the isocyanate based cross-linker component will be discussed separately. 

The water-based component is the main adhesive component in EPI adhesives. Generally, it consists of water, poly(vinyl alcohol) (PVA), one or more water-based emulsions, filler(s) and a number of additives such as defoamers, dispersing agents and biocides [1, 4, 5, 8, 9]. As with traditional thermosetting and thermoplastic wood adhesives, properties such as viscosity and solids content vary with the intended application. In the European market the typical viscosities are 2000-8000 mPa s at 25°C and the solids content is normally 50% or more. The adhesives are normally neutral with a pH in the range of 6-8 [3]. The storage stability of the EPI adhesive component is typically half a year when stored at a temperature between 10 and 30°C. 

The semisolid emulsions which may be oil-in-water (0/W) or water-in-oil (W/0) type is defined as cream, in which drugs dissolved or dispersed in emulsion bases. Cream is composed of three parts, i.e., water phase, oil phase and surfactants. Because of its hydrophobicity, among others, stearic acid is frequently used as oil phase component. 

Silver and silver alloys are used for electrical contacts, connecting leads in semiconductor devices, solders and brazes, corrosion-resistant structural parts, batteries, oxidation catalysts, optical and heat reflecting mirrors, table ware, jewellery, dentistry, and coins. Silver halides are base components in photographic emulsions. 

With liquid drug preparations, separation of the additives and base before chromatography is in most cases impossible or only partly possible. These substances are thus carried over into the chromatographic separation. Examples of this are to be found in Table 121/5 and 6. As shown in Fig. 165, the experimental conditions for the steroid emulsion. Table 121/5, are chosen in such a way that, apart from the emulsion base remaining at the start, two other emulsion constituents are separated from the two active steroid components during development. In the example of sesame oil preparations. Table 121/6, a suitable solvent displaces the lipophilic oil, serving as excipient, to the solvent front and... 

Fig. 165). The spots with the highest and lowest hi /-value are components of the emulsion base...

Adhesives for Laminated Films. Laminated films are currently produced by two techniques lamination and extrusion. In lamination, the low-viscosity adhesive solution is applied by rolls to one of the films in a thickness of a few micrometers and dried. The two films are then combined in the laminator. The adhesives used are either two-component or one-component, moisture-cross-linking polyurethane adhesives, depending on requirements (type of film, sterilization resistance, sealing seam strength, etc.). Besides the traditional solvent-based systems developments have been made in the direction of solvent-free systems (high-solids products) and of polyurethane emulsion-based systems. 

Li, Y., Hu, M., Xiao, H., Du, Y., Decker, E. A., McClements, D. J. (2010). Controlling the functional performance of emulsion-based delivery systems using multi-component biopolymer coatings. European Journal of Pharmaceutics and Biopharmaceutics, 76, 38-47. 

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