Films film formers

Film former Film growth Film, photographic... 

Formulation Aids. Formulation aids, which include carriers, binders, fillers (qv), plasticizers (qv), and film-formers, are ingredients used in processing to impart a particular physical state or textural characteristic. Table 5 gives an overview of the formulation aids used in the food industry. 

Gums are used in industry because their aqueous solutions or dispersions possess suspending and stabilising properties. In addition, gums may produce gels or act as emulsifiers, adhesives, flocculants, binders, film formers, lubricants, or friction reducers, depending on the shape and chemical nature of the particular gum (2). Considerable research has been carried out to relate the stmeture and shape (conformation) of some gums to their solution properties (3,4). 

Locust bean gum and its derivatives are exceUent film formers and can be used either alone or in combination with starch as textile sizing agents and dye thickeners in textile printing, and as fiber bonding and beater additives in the papermaking industry. However, in most of these appHcations it has been replaced by guar. 

Several classes of polymers containing the HFIP-O group have been reported. These polymers show promise as film formers, gas separation membranes, coatings, seals, and other high temperature apphcations due to the properties imparted by this function, similar in many ways to the HFIP group. 

Vinyl, alkyd, and styrene—butadiene latexes are used as film formers in most architectural coatings. Because alkyd resins (qv) require organic solvents, their use has decreased substantially for architectural coatings, but is stiU holding up in industrial appHcations, where their greater durability justifies the added expense (see Latex technology). 

Chemical modification of the wax can improve smear resistance (5). Sihcones, which do not harm furniture finishes (6), are incorporated as film-forming ingredients in furniture pohshes. The lubricant properties of sihcones improve ease of apphcation of the pohsh and removal of insoluble soil particles. In addition, sihcones make dry films easier to buff and more water-repeUent, and provide depth of gloss, ie, abihty to reflect a coherent image as a result of a high refractive index (7). Wax-free pohshes, which have sihcones as the only film former, can be formulated to dehver smear resistance (8). Another type of film former commonly used in oil-base furniture pohshes is a mineral or vegetable oil, eg, linseed oil. 

One of the important attributes of alkyds is their good compatibiUty with a wide variety of other coating polymers. This good compatibiUty comes from the relatively low molecular weight of the alkyds, and the fact that the resin stmcture contains, on the one hand, a relatively polar and aromatic backbone, and, on the other hand, many aUphatic side chains with low polarity. An alkyd resin in a blend with another coating polymer may serve as a modifier for the other film-former, or it may be the principal film-former and the other polymer may serve as the modifier for the alkyd to enhance certain properties. Examples of compatible blends foUow. 

Cyclohexylamine is miscible with water, with which it forms an azeotrope (55.8% H2O) at 96.4°C, making it especially suitable for low pressure steam systems in which it acts as a protective film-former in addition to being a neutralizing amine. Nearly two-thirds of 1989 U.S. production of 5000 —6000 t/yr cyclohexylamine serviced this appHcation (69). Carbon dioxide corrosion is inhibited by deposition of nonwettable film on metal (70). In high pressure systems CHA is chemically more stable than morpholine [110-91-8] (71). A primary amine, CHA does not directiy generate nitrosamine upon nitrite exposure as does morpholine. CHA is used for corrosion inhibitor radiator alcohol solutions, also in paper- and metal-coating industries for moisture and oxidation protection. 

Cured amino resins are far too brittle to be used alone as surface coatings for metal or wood substrates, but in combination with other film formers (alkyds, polyesters, acryUcs, epoxies) a wide range of acceptable performance properties can be achieved. These combination binder coating formulations cure rapidly at slightly elevated temperatures, making them well suited for industrial baking appHcations. The amino resin content in the formulation is typically in the range of 10—50% of the total binder soHds. 

A wide selection of amino resin compositions is commercially available. They are all alkylated to some extent in order to provide compatibiUty with the other film formers, and formulation stabiUty. They vary not only in the type of amine (melamine, urea, ben2oguanamine, and glycolutil) used, but also in the concentration of combined formaldehyde, and the type and concentration of alkylation alcohol (/ -butanol, isobutyl alcohol, methanol). 

On curing, amino resins not only react with the nucleophilic sites (hydroxyl, carboxyl, amide) on the other film formers in the formulation, but also self-condense to some extent. Highly alkylated amino resins have less tendency to self-condense (33,34) and are therefore effective cross-linking agents, but may require the addition of a strong acid catalyst to obtain acceptable cure even at bake temperatures of 120—177°C. 

PVP ISP/PVP, Plasdone K-15 to K-120 K-12 to K-90 film former, adhesive, binder, com-plexant. 

PVP/DMAEMA ISP / copolymer 845/937/958 mildly cationic, hair styling aids and conditioners, with strong hold sub-stantive, lustrous film-formers... 

PVP/alpha-olefins ISP/Ganex various (olefin chain length surface active film formers waterproofing... 

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. 

D. H. Solomon, The Chemistry of Organic Film Formers, 2nd ed., Robert E. Krieger Publishing Co., Huntington, N.Y., 1977. 

FeaC films at former y grain boundaries + nodules of pearlite... 

Binders are the film formers. After application, they turn from liquids to solids. Different types of paint have. 

The basic mechanism of passivation is easy to understand. When the metal atoms of a fresh metal surface are oxidised (under a suitable driving force) two alternative processes occur. They may enter the solution phase as solvated metal ions, passing across the electrical double layer, or they may remain on the surface to form a new solid phase, the passivating film. The former case is active corrosion, with metal ions passing freely into solution via adsorbed intermediates. In many real corrosion cases, the metal ions, despite dissolving, are in fact not very soluble, or are not transported away from the vicinity of the surface very quickly, and may consequently still... 

The common defects arising in processing include etching —preferential attack of grain boundaries —which occurs if the film has not fully formed it may be exploited in certain circumstances because the finish can be artistically attractive and the surface area may be increased. Pitting occurs if the film is disrupted at local sites, either by incorrect balance of film former/contaminant or by gas evolution on the surface. 

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