Aluminum oxide extrusion

ETFE resins have a good thermal stability however, for high-temperature applications thermal stabilizers are often added67 A wide variety of compounds, mostly metal salts, such as copper oxides and halides, aluminum oxide, and calcium salts, will act as sacrificial sites for oxidation. Addition of certain salts can alter the decomposition from oligomer formation to dehydrofluorination. Iron and other transition metal salts accelerate the dehydrofluorination. Hydrofluoric acid itself destabilizes ETFE at elevated temperatures and the degradation becomes self-accelerating. For that reason, extrusion temperatures higher than 380°C (716°F) should be avoided.68... 

Increased rates of production of about 500 m/min and higher filament dimensional stabilities can be achieved with extrusion spinning or gel or gel extrusion spinnings whereby 35%-55% solutions are spun. Examples of organic fiber formers are poly(acrylonitrile) and poly(vinyl alcohol). Aluminum oxide is an example of inorganic material. 

Almost 85 % of aluminum is used for wrought products such as rolled plates, foils, and extrusions [16]. Cast aluminum alloys provide cost-effective products but usually have lower tensile strengths than those of wrought alloys. Aluminum alloys are used in engineering, the aerospace industry, and for components where corrosion resistance or light weight is needed. If left unprotected their surfaces are anodized, which means that they form a white protective layer of the corrosion product, aluminum oxide. 

In contrast to most extmsion processes, extrusion coating involves a hot melt, ca 340°C. The thin web cools rapidly between the die and nip even at high linear rates. Both mechanical and chemical bonding to substrates are involved. Mechanical locking of resin around fibers contributes to the resin s adhesion to paper. Some oxidation of the melt takes place in the air gap, thereby providing sites for chemical bonding to aluminum foil. Excessive oxidation causes poor heat-sealing characteristics. 

Manufacturers of various fillers continue studies on altemative systems. Most antimony oxide used as a fire retardant can be replaced by a combination of zinc borate without the loss of other properties (in some cases improvements are reported). Another option is to use the same filler systems which are used in polyethylene insulated cables and wires. These are based on magnesium hydroxide and aluminum hydroxide. These systems pcrfoim as flame retardants but require a high filler concentration which affects jacket resistance and mechanical performance. Recently, new coated grades have been developed which can be used at up to 65 wt% without the loss of properties or productivity (extrusion rates 2,500 m/min of cable are possible). ... 

Typical floor structures of cars are shown in O Fig. 47.7 (Suzuki 2007). The case of 700 series Shinkansen car is shown in Fig. 47.7a. A heat insulating material made of oxidized acrylic fibers is installed on the aluminum extrusions. Floor plates of aluminum-aluminum honeycomb sandwich structure bonded with a film type epoxy adhesive are screwed on it. Floor covering made of nonrigid PVC are bonded with a nitrile rubber adhesive. 

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