Dry coating

Fig. 2. Touch-and-drain dry chemistry constmction (a) dry coated surface (b) cross-section of dry coated surface, adhesive, and cover piece (c) contact with blood drop results ia blood filling the cavity. After desired reaction time, blood is drained off by touching end of cavity with absorbent material (6).

Substituted heat-reactive resins are most widely used in contact-adhesive appHcations and, to a lesser extent, in coatings (77,78) -butylphenol, cresol, and nonylphenol are most frequendy used. The alkyl group increases compatibiHty with oleoresinous varnishes and alkyds. In combination with these resins, phenoHcs reduce water sensitivity. Common appHcations include baked-on and electrical insulation varnishes, and as modifiers for baking alkyds, rosin, and ester gum systems. Substituted heat-reactive resins are not used for air-dry coatings because of theh soft, tacky nature in the uncured state substituted nonheat-reactive phenoHcs are the modifying resin of choice in this case. 

Different phenoHc resins are used for different types of wood for example, plywood adhesives contain alkaline-catalyzed Hquid resole resins. Extension with a filler reduces cost, minimizes absorption, and increases bond strength. These resins have an alkaline content of 5—7% and are low in free phenol and formaldehyde. Because many resins have a high water content and limited storage stabiHty, they are frequently made at or near the mill producing the plywood product. The plywood veneers are dried, coated with resin, stacked for pressing, and cured at 140—150°C. 

The use of nylon-11 for powder coatings or dry coatings (qv) has been developed in response to a growing concern for the environment (44) (see Coating PROCESSES, powder technology). Electrostatic deposition allows thin films to be appHed to metal substrates. Once the powder is appHed, it must be melted and coalesced into a continuous plastic film. Eorced draft or irradiant ovens are used for fusion, and because no polymerization or cross-linkage are required for curing, coated objects can be processed quickly and air-cooled (45). 

Radiation-curable epoxy acrylates, 10 450 Radiation cures, silicone network preparation via, 22 567-569 Radiation curing coatings, 7 133-135 of printing inks, 14 314 Radiation damage, ion implantation and, 14 435-436 Radiation drying coatings, 7 29-30 Radiation effects... 

Zhou, Q., Armstrong, B., Larson, I., Stewart, P. J., Morton, D. A. V. Improving powder flow properties of a cohesive lactose monohydrate powder by intensive mechanical dry coating. J. Pharm. Sci., 99, 2010, 969-981. 

Keywords. Hyperbranched polyesteramides. Polymers, Powder coatings. Air drying coatings. Dyeing polyolefins... 

Loss of Adhesion When Wet. Many coatings, particularly those applied to a roughened surface, show excellent tensile adhesion to steel but lose this adhesion after exposure to pure water at room or elevated temperatures. A thin film of water at the interface is apparently responsible for the loss of adhesion. If the coating is allowed to dry without destructively testing the adhesion, the dried coating often exhibits the original tensile adhesion. The phenomenon is... 

Lacquer A rapid-drying coating by evaporation of solvent only. It will redissolve in the solvent, and it may be lightly pigmented. 

As with fatty acids, organo-silanes can be applied by both wet and dry coating methods. In the present context, wet coating is principally restricted to glass fibre coating, where it can be incorporated into the size, which is already applied from water. Dry coating is the preferred method for coating mica, wollastonite clays and metal hydroxides. 

Dry coating is probably the main method used in preparing products for thermoplastic applications. Due to the cost of additional drying operations, it is the method of choice when the filler itself is produced by a dry process. It is also useful where wet coating procedures would give rise to effluent problems. 

Dry coating is extensively used with fatty acid treatment of natural calcium carbonates. The challenge is to convert as much as possible of the coating to a bound surface layer, with as little unbound salt and remaining free acid as possible. There is little scientific literature on this procedure but some useful studies have been made[51,64]. A number of different methods are employed. In most cases, unless a small amount of solvent is used, it is necessary for the procedure to be carried out at a temperature where the fatty acid blend is molten. With stearate mixtures this is about 80 °C. Some fatty acids such as iso-stearic acid have the advantage of being liquid at room temperature, but are not widely used as they are more expensive. 

Much of the natural calcium carbonate used in thermoplastics is fatty acid treated. Manufacturers give little detail about their coating processes but it is likely that both wet and dry coating procedures are utilised. 

Many surface modifications are used with aluminium hydroxide, which responds to both silane and fatty acid treatments. Special proprietary silane coatings seem to be preferred for polypropylene applications [99]. Despite the production being water based, the preference seems to be for dry coating procedures. 

This formula is able to clear the heat from the Xue level. It removes fire-toxin, cools the blood, nourishes the Yin, dispels blood stasis and stops bleeding. It is used for fever, various types of bleeding, erythema and purpura with a deep purple color, thirst and delirium. Patients may have a deep-red tongue with a very dry coating and a rapid and thready pulse. 

In the aftermath of heat at the Qi level, although the body fluids and the Qi are injured, neither the damage nor the symptoms are serious. The recovery period is fairly short. Manifestations include tiredness, poor appetite and difficulty falling asleep, a red tongue with a dry coating and a rapid pulse. 

Palpitations and anxiety with a red tongue with a dry coating add Sheng Di Huang Rehmanniae radix) and Mai Men Dong... 

This formula is devised to treat internal wind stirred up by excess heat in the Liver and Heart. A high fever with irritability, convulsions with possible loss of consciousness, a deep red tongue with a dry coating and a wiry and rapid pulse indicate excess heat. 

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