Polymeric film-former

In principle, emulsified sunscreen products are similar to emollient skin-care products in which some of the emollient Hpids are replaced by uv absorbers. The formulation of an effective sunscreen product generally requites combination of a uvB and a uvA absorber if an SPF above about 12 is desired. Two or more of the sunscreens Hsted in Table 13 normally constitute about one-half of the nonvolatiles found in sunscreen lotions. The other half consists of an em ollient (solvent) and emulsifying and bodying agents. If water-resistant quaUties are desired, polymeric film formers, for example, acrylates—octylacrylamide copolymers [9002-93-1] or water-repellent Hpids, for example, dimetbicone [9006-65-9] are included. 

Eyeliners are available in two popular forms. One of these is a deeply pigmented emulsion that is appHed with a fine bmsh. The emulsion must be viscous to avoid miming and should dry to a waterproof film. The emulsion can be patterned after the emulsions used in mascaras. Glossy eyeliners require the use of nacreous pigments suspended in polymeric film formers, for example, acryUc acid copoljmiers. 

The primary coating materials, usually polymeric (film formers), often require the addition of other excipients such as plasticizers, pore formers, colorants, or antiaggregation agents for the coating to perform in the desired fashion or for the product to be manufactured conveniently.2 These components have been the subject of numerous studies and reviews.31,32 The components that affect/modify the release from these systems are film formers, plasticizers, and pore formers and are discussed below. 

The polymeric film formers used as non-slip finishes are typically copolymers of vinyl, acrylic and methacrylic monomers. These materials are similar in structure to the copolymers used as hand builders (see Chapter 4, Fig. 4.3 and Fig. 4.5). 

Cosmetic suspensions are available in two types. The first comprises pigmented products that are suspended in essentially aqueous vehicles (liquid makeup, eyeliners, mascara, and blusher). These products have a high solids content, high density, impalpable powders, and pigments permanently suspended in a primary oil-in-water emulsion-type base or a complex system of hydrophilic cellulose derivatives, clays, and/or polymeric film formers, in which the gelling and suspending properties of the vehicle often are reinforced by a small amount of a Bingham-type plastic such as carbomer. 

A great many of outstanding adhesive formulations are based on epoxy resins. A broad spectrum of adhesive formulations with a wide range of available properties have resulted from the use of polymeric hardeners such as polyamides and polyamines, phenolics, isocyanates, alkyds, and combinations of amines with polysulfide elastomers, and the alloying of the epoxy with compatible polymeric film-formers, such as poly(vinyl acetate) and certain elastomers. 

The next link in the rubber to metal bond is between the primer and adhesive interface. The curative present in the adhesive layer migrates or diffuses into the primer layer during vulcanisation and forms a chemical bond between the primer and adhesive. The polymeric film former present in the primer diffnses and knits with the adhesive layer and further strengthens the bond between primer and adhesive becanse of its compatibility with polymers present in the adhesive layer. The final link in the rnbber to metal bond is the adhesive to rnbber interface. The curative present in the adhesive layer also diffuses into the rubber during vulcanisation and forms a chemical bond between the adhesive and the rubber. These bonds which span across the layers in the assembly are called crossbridges to differentiate them from the crosslinks which occnr within the rnbber itself. In addition, sulphur from the rubber compound diffnses into the adhesive layer and helps to form additional crossbridges between the rnbber and the adhesive. 

The vehicle of quality paints, especially wall paints and primers, are sticky if used in high concentration because they are well-polymerized resins. This high degree of polymerization makes the product viscous and also improves adhesion, toughness, and chemical and weathering resistanee. In addition, polymerized resins prevent striking in due to their resistanee to substrate suction. These well-polymerized film formers must be diluted with solvents before application. However, the lower solid level resulting from this... 

Tannin chemistry is complex and tannin blends (composed of singletree species tannins mixed together) offer a number of useful water treatment functions. Apart from oxygen-scavenging abilities, they act as passivating agents, film-formers, sequestrants, and polymeric sludge dispersants (for more details, see Section 10.3). 

There are now many synthetic polymeric materials available for film coating, many of which meet all the requirements of a good film former. These include lack of toxicity and a suitable solubility profile for film application and upon ingestion, together with the ability to produce a tough, yet elastic film even in the presence of powdered additives such as pigments. The film must, of course, be stable to heat, light, and moisture and be free from undesirable taste or odor. 

Materials similar to Nation containing immobilized —COO- or —NR3+ groups on a perfluorinated skeleton were also synthesized. These are available in the form of solid membranes or solutions in organic solvents the former can readily be used as solid electrolytes in the so called solid polymer electrolyte (SPE) cells, the latter are suitable for preparing ion-exchange polymeric films on electrodes simply by evaporating the polymer solution in a suitable solvent. 

Suspension Polymerization Systems for Controlling Particle Size. Suspending Agents. Both types of suspension stabilizers—the finely divided water-insoluble solids and the soluble film formers—have been used extensively to prepare styrene polymers of a particle size between about 10 and 40 mesh. Examples of such materials are listed below ... 

A variety of organic-polymeric-based materials have been investigated for optical recording, including dyes (pigments), dye (pigment)-polymer composites, dye-polymer solutions, and polymer-metal-layered or particulate structures. In all instances, the light absorption function is provided by the dye or metal, and the polymer serves the role of binder and film former. 

A simple foam generation apparatus is used to incorporate air into a conventional water-soluble polymeric excipients binder such as METHOCEL hypromeUose (hydroxypropyl methylcellulose). The resulting foam has a consistency like shaving cream. HypromeUose polymers are ideal candidates for this technology because they are excellent film formers and create exceptionally stable foams. 

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