Coating specific parts

ISO 8095 1990 PVC-coated fabrics for tarpaulins - Specification ISO 8096-1 1989 Rubber- or plastics-coated fabrics for water-resistant clothing -Specification - Part 1 PVC-coated fabrics... 

Figure 1 Functions of enteric coatings according to the statements of the pharmaceutical manufacturer. 1, Taste masking 2, stability 3, protection against local irritation 4, drug release in specific parts 5, odor masking.

PTFE aqueous dispersions are applied onto metal substrates by spraying, dipping, flow coating, electrodeposition, or coagulation to provide chemical resistance, nonstick, and low-friction surfaces. Nonstick cookware and bakeware are made from dispersion specifically formulated for that purpose with the use of a primer for the metal. After coating, the parts are dried and sintered. 

Coatings are usually applied as multi-layered systems that are composed of primer and topcoat. However, in some cases - for example automotive coating systems -this may vary from four to six layers. Each coating layer is appHed to perform certain specific functions, though its activities are influenced by the other layers in the system. The interactions among different layers and the interfadal phenomenon play an important role in the overall performance of the multi-coat systems [5]. Different properties of coatings are typically associated with specific parts of a coating system (Fig. 1.1) [6]. 

The patient benefits from a less frequent dosing regimen, i.e. the release occurs over an extended period of time (e.g. clomipramine). Modified-release tablets or enteric-coating tablets do not release the active substance directly, but do so in a specific part of the gastro-intestinal tract, either delayed or with a specific release pattern. The release of these tablets is adjusted to therapeutic needs of the patient. 

In nonweb applications the coating is applied to a specific part at the end of the fabrication process. The part is usually three-dimensional and of varying shape. Automobiles, appliances, and steel structures all have the coating applied to the individual items as they are being built. It should be noted that many smaller steel items are made from prepainted sheet steel. 

Edible coatings are films formed directly in the food surface by inunersion of the food product in the coating solution (Krochta and De Mulder-Johnston, 1997). Therefore, coatings are part of food products to protect or enhance them in some characteristic and they can be directly eaten or removed before consumption Moreover, edible coatings can be improved by the addition of active substances to form active food packaging, enhancing functional or specific properties of foods, such as the control of food oxidation and microbial growth (Cuq et al., 1995 Han, 2001 Jarimopas et al., 2007). 

Adhesive Transfer Processes. Many polymers, whether dehberately or accidentally, are adhesives, so that much of the adhesive industry can be regarded as a part of the mbber and plastics industry. However, there are several important material-transfer appHcations involving polymer products that are so critically dependent on controlled adhesion that they merit specific mention in that category. They include hot stamping foils, release coatings for pressure-sensitive adhesive products, photocopier materials, transfer coatings, and transfer printing of textiles. 

Most general-purpose release agents have been developed for this market in part because of their low toxicity and chemical inertness and do not usually present health and safety problems. Some of the solvent dispersions require appropriate care in handling volatile solvents, and many supphers are offering water-based alternatives. Some of the sohds, particularly finely divided hydrophobic sohds, can also present inhalation problems. Some of the metallic soaps are toxic, although there is a trend away from the heavier, more toxic metals such as lead. The reactive type of release coating with monomers, prepolymers, and catalysts often presents specific handling difficulties. The potential user with health and safety questions is advised to consult the manufacturer directly. 

---