Metallizing plastics

The polymers of the 2-cyanoacryhc esters, more commonly known as the alkyl 2-cyaiioacrylates, are hard glassy resins that exhibit excellent adhesion to a wide variety of materials. The polymers are spontaneously formed when their Hquid precursors or monomers are placed between two closely fitting surfaces. The spontaneous polymerisation of these very reactive Hquids and the excellent adhesion properties of the cured resins combine to make these compounds a unique class of single-component, ambient-temperature-curing adhesives of great versatiUty. The materials that can be bonded mn the gamut from metals, plastics, most elastomers, fabrics, and woods to many ceramics. 

A fiber dmm is a cylindrical shipping container made of convolutely wound layers of fiberboard adhered to each other to form a soHd wall. Constmction materials for the ends include metal, plastic, and fiberboard. Fiber dmms are subject to DOT and, for international shipment, U.N. regulations when used forha2ardous materials. Reference to these regulations is necessary before selecting a fiber dmm. 

Calcined aluminas are also used for polishing appHcations by mixing into polishing compounds in the form of paste or suspensions. Polishing aluminas are used to alter the surfaces of metals, plastics, glass, and stones in the manufacture of cutlery, automobiles, computers, furniture, eyewear, semiconductors, and jewelry. Polishing aluminas are also used to coat surfaces, such as video tapes (1). 

Filter Press The filter press, one of the most frequently used filters in the early years or the chemical industry, is still widely employed. Often referred to genetically (in error) as the plate-and-frame filter, it has probably over 100 design variations. Two basic popular designs are the flush-plate, or plate-and-frame, design and the recessed-plate press. Both are available in a wide range of materials metals, coated metals, plastics, or wood. 

Disk Filters A disk filter is a vacuum filter consisting of a number of vertical disks attached at intervals on a continuously rotating horizontal hollow central shaft (Fig. 18-127). Rotation is by a gear drive. Each disk consists of 10 to 30 sectors of metal, plastic, or wood, ribbed on both sides to support a filter cloth and provide drainage via an outlet nipple into the central shaft. Each sector may be replaced individually. The filter medium is usually a cloth bag slipped over the sectors and sealed to the discharge nipple. For some heavy-duty applications on ores, stainless-steel screens may be used. 

Ordnance and accessories Manufacturing, assemhhng Metals, plastic, rubber, paper, wood, cloth, chemical residues... 

Apparel and other finished products Cutting, sewing, sizing, pressing Cloth, fibers, metals, plastics, rubber... 

Lumber and wood products Sawmills, millwork plants, wooden containers, miscellaneous wood products, manufacturing Scrap wood, shavings, sawdust in some instances, metals, plastics, fibers, glues, sealers, paints, solvents... 

Professional scientific controlling instruments Manufacture of engineering, laboratory, and research instruments and associated equipment Metals, plastics, resins, glass, wood, rubber, fibers, abrasives... 

Rupture Disks A rupture disk is a device designed to function by the bursting of a pressure-retaining disk (Fig. 26-15). This assembly consists of a thin, circular membrane usually made of metal, plastic, or graphite that is firmly clamped in a disk holder. When the process reaches the bursting pressure of the disk, the disk ruptures and releases the pressure. Rupture disks can be installed alone or in combination with other types of devices. Once blown, rupture disks do not reseat thus, the entire contents of the upstream process equipment will be vented. Rupture disks are commonly used in series (upstream) with a relief valve to prevent corrosive fluids from contacting the metal parts of the valve. In addition, this combination is a reclosing system. 

Lower pressure drop (less than half) than Raschig rings, also lower HTU (in some systems also lower than Bert saddles), higher flooding limit. Good liquid distribution, high capacity. Considerable side thmst on column wall. Available in metal, plastic and ceramic. 

A wide variety of containers of differing capacity and design are used for solids transport, i.e. fibreboard, metal, resin-lined metal, plastic drums plastic, paper or hessian sacks tote bins bulk tanker lorry-load. The material may then be stored in the containers as received, in hoppers or silos, or simply in piles depending upon its properties and value. 

The other principal thermal properties of plastics which are relevant to design are thermal conductivity and coefficient of thermal expansion. Compared with most materials, plastics offer very low values of thermal conductivity, particularly if they are foamed. Fig. 1.10 shows comparisons between the thermal conductivity of a selection of metals, plastics and building materials. In contrast to their low conductivity, plastics have high coefficients of expansion when compared with metals. This is illustrated in Fig. 1.11 and Table 1.8 gives fuller information on the thermal properties of pl tics and metals. 

Piping A metallic, plastic, glass, etc. enclosure, for the conveying of a fluid, vapor, or gas. 

A rupture disk is a non-reclosing thin diaphragm (metal, plastic, carbon/graphite (non-metallic)) held between flanges and designed to burst at a predetermined internal pressure. Each bursting requires the installation of a new disk. It is used in corrosive service, toxic or leak-proof applications, and for required bursting pressures not easily accommodated by the conventional valve such as explosions. It is applicable to steam. 

Various materials (e.g., metal, plastics, or rubber) are used to make the flexing elements in these couplings. The use of the couplings is governed by the operational fatigue limits of these materials. Practically all metals have fatigue limits that are predictable, therefore, they permit definite boundaries of operation to be established. Elastomers such as plastic or rubber, however, usually do not have a well-defined fatigue limit. Their service life is determined primarily by conditions of installation and operation. 

The chief advantage of wood for containers is that many common species are free from harmful contaminants. For this reason wood had widespread use in the food and beverage industries, but it has now suffered severe competition from corrosion-resistant metals, plastics and paper products. Oak had a very extensive use in tight cooperage in the brewing industry, and its use for barrels still survives in the maturing of whisky and brandy and in the wine industries. Wood is particularly useful where acetic acid is present as this acid is corrosive to most common metals. 

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