Film-coating colorants

AppHcation of an adhesion-promoting paint before metal spraying improves the coating. Color-coded paints, which indicate compatibiHty with specific plastics, can be appHed at 20 times the rate of grit blasting, typically at 0.025-mm dry film thickness. The main test and control method is cross-hatch adhesion. Among the most common plastics coated with such paints are polycarbonate, poly(phenylene ether), polystyrene, ABS, poly(vinyl chloride), polyethylene, polyester, and polyetherimide. 

The particular colors that are observed at different angles will depend critically on the thickness of the thin film coating. Precision instrumentation is required to carefully control film thickness during production. The magnitude of the optical effect depends on the density of flakes in the ink, while the quality of the optical effect depends on the precise orientation or alignment of these flakes with respect to the paper surface. 

Matsuda, Y., Inouye, H., and Nakanishi, R. (1978), Stabilization of sulfisomidine tablets by use of film coating containing UV absorber Protection of coloration and photolytic degradation from exaggerated light, /. Pharm. Sci., 67,196-201. 

Components and composition Example Deletion or partial deletion of ingredient —> color, flavor, or ink. Changes in excipients as % (w/w) of total < specified ranges8 Filler +5 Disintegrant Starch +3 Other +1 Binder +0.5 Lubricant Ca or Mg stearate +0.25 Other +1 Glidant Talc +1 Other +0.1 Film coat +1 Note total NGT 5%... 

Teraoka R, Matsuda Y, Sugimoto I. Quantitative design for photostabilisation of nifedipine by using titanium dioxide and/or tartrazine as colorants in model film coating systems. J Pharm Pharmacol 1989 41 293-297. 

Yamada-Takamura, Y. et al.. Hydrogen permeation barrier performance characterization of vapor deposited amorphous aluminum oxide films using coloration of tungsten oxide. Surface and Coatings Technology, 153, 114 (2002). 

VIKON FGT forms a clear, continuous film of high resistance to abrasion on fabrics and can be used for coating colored yarn fabrics for slip-covers, etc. It is also an excellent latex for making water based paints for painting awnings, tarpaulins, etc. The coating formed has high resistance to submersion under water. 

Film-coating was developed early in the 1950s to help resolve many of the problems associated with sugar-coating. It involves the application of a film-forming polymer onto the surface of a substrate (such as tablets, granules, and capsules). In addition to the polymer, the film contains plasticizers and colorants, which are needed to achieve the desired properties in the final dosage form. 

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