Sheet casting

Methacrylate polymerizations are accompanied by the Hberation of a considerable amount of heat and a substantial decrease in volume. Both of these factors strongly influence most manufacturing processes. Excess heat must be dissipated to avoid uncontrolled exothermic polymerizations. Volume changes are particularly important in sheet-casting processes where the mold must compensate for the decreased volume. In general, the percent shrinkage decreases as the size of the alcohol substituent increases on a molar basis, the shrinkage is relatively constant (35). 

Welcast Plastics Company produces sheet castings for covers for welding-mask lenses. These covers for welding-mask lenses. These covers are resistant to hot metal fragments. 

Various methacrylate esters have been disclosed as modifiers of DADC. Thus methyl methacrylate polymer may be dissolved in DADC and the sheets cast (22). When DADC is copolymerized with methyl methacrylate, a silane derivative may be added to control the release from the mold (23). 

Continuous sheet casting Solution heat treatment... 

ISO 17557 2003 Plastics - Film and sheeting - Cast polypropylene (PP) films... 

Casting, continuous sheet casting between stainless-steel belts, pouring and several methods in the molten state are usable extrusion, injection, compression, thermoforming, co-injection, machining, welding. Specific grades of PMI can be foamed. 

Polypropylenes are available as molding powder, extruded sheet, cast film, textile staple, and continuous-filament yarn. They find use in packaging film molded parts for automobiles, appliances, and housewares wire and cable coating food container closures bottles, printing plates carpet and upholstery fibers storage battery cases crates for soft-drink bottles laboratory ware trays fish nets surgical casts and a variety of other applications. 

The relaxation measurements on sheets cast from cyclohexane solution were made in the same way at 15 temperatures from —70° to 80°C. Two sheets were cast from tetrahydrofuran solution. Relaxation measurements were made at 4% strain at 10 temperatures between —70° and 70°C, and at 8% strain at 9 temperatures between —70° and 70°C. 

Creep tests in uniaxial tension were made at 11 temperatures between —70° and 75°C on strips which were cut 1.27-cm wide, 0.12-cm thick, and 20.0-cm long from a sheet cast from benzene solution. The distance between the grips was 19.0 cm. Bench marks were placed 15.0 cm apart. Displacements were read from the bench marks using a power driven cathetometer of 0.0002-cm sensitivity. The creep tests covered a minimum range of about four decades of time beginning at 10 seconds. The measurements were repeated at 15°, 30°, 40°, and 50°C on a second sheet, also cast from benzene solution. Measurements derived... 

Available forms (Molding powder) Extruded sheet, cast film (1-10 mils), textile staple and continuous filament yarn, fibers with diameters from 0.05 to 1 p,m, and fiber webs down to 2 microns thick, low-density foam. 

Figure 5.5 Cross section and surface of a microporous polysulfone sheet used in composite reverse osmosis membranes (a) total cross section of a polysulfone sheet cast on a nonwoven polyester fabric, then delaminated prior to freeze-fracture for SEM (note fiber trecks on backside of the sheet) (b) backside of sheet showing cellular structure, which extends through 85% of the sheet thickness (c) transition region from cellular to nodular structure near film surface (d) dense nodular structure at the surface (e) high magnification of the extreme top surface cross section (f) high magnification view of the surface structure showing tha texture of the top surface.

Information Sheet, Cast Infrared-Producing Flares, Flare-Northern Div., Atlantic Research Corp. 

Chem. Descrip. Triphenyl phosphate CAS 115-86-6 EINECS/ELINCS 204-112-2 Uses Flame retardant, plasticizer for photographic safety film, sheets, cast triacetate film (primary plasticizer), molded acetate prods., nitrocellulose, ethyl cellulose, and cellulose acetate butyrate coatings, ABS, unsat. polyester, PVAc, PVC, flexible PU foam Features Mostly used combined with other plasticizers improves dimensional stability and dielec. str. 

Casting and sheets Casting PP fine film 10-50 gm cast film 100-400 jm thermoformable sheet 200-2500 gm. High impact PS. also HDPE, PVC, ABS. Sheet thickness > 0.25 mm film < 0.25 mm. (although blown film < 0.5 mm). Coating wire and cable Usually PE and PVC coating on wire. 

Methyl methacrylate acrylic resin sheet, cast PEG-3 dimethacrylate acrylic resin sheet, crosslinked Methacrylamide... 

Pipe, tubing, sheet, cast film, profile Injection molding, resin injection molding... 

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