Tape drying

In laboratory operations, batch casting with a mobile doctor blade and stationary carrier are used. Plate glciss is usually used as a carrier. Tape drying can take place on the support by electric heaters placed imder the support. If only partial drying occurs, the tape, with or without the support, is placed in an oven to complete the dr5dng. Tapes of 0.5 m wide, 2 m long and 1-2 mm thick can be obtained. 

PPQ with inherent viscosity of 0.61 dL/g and Tg = 318 C forTi/Ti, 112 E-glass with A-1100 finish, tape dried to 4% volatile content other panels, unsupported PPQ film had -4% volatiles... 

The reagent is conveniently stored as a solution in isopropyl alcohol. The molten (or solid) alkoxide is weighed out after distillation into a glass-stoppered bottle or flask and is dissolved in sufficient dry isopropyl alcohol to give a one molar solution. This solution may be kept without appreciable deterioration provided the glass stopper is sealed with paraffin wax or cellophane tape. Crystals of aluminium isopropoxide separate on standing, but these may be redissolved by warming the mixture to 65-70°. 

Tensile properties of importance include the modulus, yields, (strength at 5% elongation), and ultimate break strength. Since in many uses the essential function of the film may be destroyed if it stretches under use, the yield and values are more critical than the ultimate strength. This is tme, for example, where film is used as the base for magnetic tape or microfilm information storage. In some cases, the tensile properties at temperatures other than standard are critical. Thus if films are to be coated and dried in hot air ovens, the yield at 150°C or higher may be critical. 

Shipment and Storage. Sulfur dichloride, if kept dry, is noncorrosive at ambient temperatures, thus carbon steel and Hon can be used Hi the constmction of tanks, piping, and dmms. However, when water or humidity is present, materials resistant to hydrochloric acid must be used, eg, glass-lined pipe. Teflon, titanium, HasteUoy C, or possibly a chemically resistant, glass-reiaforced polyester. Threaded pipe joHits should be assembled with Teflon tape. Hoses should be constmcted with a Teflon inner lining with the outer tube constmcted of Neoprene or braided 316 stainless steel protected by an adequate thickness of Teflon. Sulfur dichloride should be stored away from heat and away from dHect rays of the sum. Toluene and sulfur dichloride react exothermically when catalyzed by Hon or ferric chloride. Safety precautions should be foUowed when such a mixture is present (165). 

Tape can be cast on a stainless steel table or belt, glass plate, or a Mylar, Teflon, or ceUulose acetate film carrier. The tape should adhere to the carrier sufficiently to prevent curling, but should be easily removable. In a continuous casting process, the tape is dried by air flowing 1—2 m/min counter to the casting direction. A typical dry green tape contains approximately 35 vol % organics, 50% ceramic powder, and 15% porosity. 

Aluminium and stainless steel Extra heavy black iron or steel for dry gas. Drop forged steel, PTEE tape. 

All glassware is oven-dried. The dropping funnel is wrapped with heating tape, and a thermometer is inserted between the funnel and the tape. 

---