Barrier films/coatings

The use of a barrier film coating is only one of several procedures that can be adopted to... 

Chem. Descrip. Aq. moisture barrier film coating system Uses Moisture barrier for coating oral and solid dosage pharmaceuticals, tablet sealing and polishing appiics. 

Methoxyethyl acrylate barrier, enteric coatings Certified Pharmaceutical Glaze barrier, film coatings Michem Lube 110 barrier, high-gloss finishing Certified Pharmaceutical Glaze barrier, incompat. active substances Kollicoat MAE 30 DP barrier, latex paints Michem Lube 110 Michem Lube 155 Michem Lube 180 Michem Lube 188... 

Diethylene glycol dimethacrylate crosslinking agent, moisture barrier film Diethylene glycol dimethacrylate crosslinking agent, moisture barrier films/ coatings... 

Triallyl isocyanurate coagent, moisture barrier film/coatings... 

Alkenylsuccinic anhydrides made from several linear alpha olefins are used in paper sizing, detergents, and other uses. Sulfosuccinic acid esters serve as surface active agents. Alkyd resins (qv) are used as surface coatings. Chlorendric anhydride [115-27-5] is used as a flame resistant component (see Flame retardants). Tetrahydrophthalic acid [88-98-2] and hexahydrophthalic anhydride [85-42-7] have specialty resin appHcations. Gas barrier films made by grafting maleic anhydride to polypropylene [25085-53-4] film are used in food packaging (qv). Poly(maleic anhydride) [24937-72-2] is used as a scale preventer and corrosion inhibitor (see Corrosion and corrosion control). Maleic anhydride forms copolymers with ethylene glycol methyl vinyl ethers which are partially esterified for biomedical and pharmaceutical uses (189) (see Pharmaceuticals). 

Measurements of pressure-area (jc-A) isotherms and transfers of monolayers on a substrate were carried out by using a computer-controlled film balance system (San-Esu Keisoku, Co., Fukuoka, FSD-20). Maximum surface area on the trough was 475 X 150 mm2. The trough surface and the moving barrier were coated with Teflon, and the subphase was temperature-controlled with a thermostat (20 0.5 °C). The concentration of lipid solutions was 1 mg/ml and the spreading amount of lipid solutions was 50 - 150 pi. After solvent evaporation, the monolayer was compressed at the speed of 0.60 cm2 s-i. Measurements of n-A isotherms and transfers of monolayer on a QCM substrate were performed automatically with the usual manner [26,27]. 

Edible film and coating is defined as a thin, continuous layer of edible material used as a coating or as a film placed between food components to provide a barrier to mass transfer (Balasubramaniam et al., 1997 Guilbert et al., 1997). These films/coatings have the potential to replace conventional packaging in some applications. Starches such as potato starch, cellulose... 

Copolymerization. Vinyl chloride can be copolymerized with a variety of monomers. Vinyl acetate, the most important commercial comonomer, is used to reduce crystallinity, winch aids fusion and allows lower processing temperatures. Copolymers are used in flooring and coatings. This copolymer sometimes contains maleic add or vinyl alcohol (hydrolyzed from the poly(vinyl acetate ) to improve the coating s adhesion to other materials, including metals, Copolymers with vinylidene chloride are used as barrier films and coatings. Copolymers of vinyl chlonde with acrylic esters in latex from are used as film formers in paint, nonwoven fabric binders, adhesives, and coatings. Copolymers with olefins improve thermal stability and melt flow, but at some loss of heat-deflection temperature,... 

Similar studies of moisture transport across a barrier also have been done using in vitro methods that determine the movement of water vapor across a film coated with a measured amount of the material to be tested. These are rapid methods for rough determinations of occlusivity and work very well for screening several ingredients at a reasonable cost. Once again, petrolatum s occlusivity has been shown in tests of this nature.28,29... 

Aluminum metallized films provide a barrier to light which cannot be achieved with conventional lacquering or coating. For instance, a 2 O.D. metallization has a light transmittance of only 1%. In this respect, only aluminum foil is superior to metallized films. Barrier films or coatings such as PVDC, EVOH, and SiO are relatively clear and therefore have a clear disadvantage in application when both barrier and light protection are necessary. 

Porous-type coatings exhibit a duplex structure consisting of an inner barrier layer and a crystalline outer layer that consists of a regularly spaced array of pores in certain cases. As with barrier film formation, Al3+ cation and O2 and OH anion transport occurs during anodization, but in this case Al3+ is ejected into solution instead of participating in film formation. The Al3+ then reprecipitates on the previously existing barrier layer leading to the formation of a porous outer layer (89,96). 

---