Coating extruder line

Figure 5.1 5 Coating extruder line highlights the hot melt contacting the substrate just prior to entry into the nip of the pressure-chill rolls...

Chlorinated polyether used in temperatures up to 120°C in forms of coatings, extruded pipe and sheet linings is an intermediate between the low-cost commodity polymers such as PVC and polyethylene, and fluorinated polymers [61 ]. 

In general two types of secondary coatings are used in conjunction with the primary coatings described above. UV-curable epoxy acrylates or urethane acrylates are commonly used for in-line application, as the fiber is drawn. These same materials are also used extensively as single coatings. Extruded thermoplastics, such as nylon or polyester elastomers, are frequently used for off-line application processes. 

Uses Thermoplastic resin for inj. molding and extrusion applies., tire cord, filaments, fishing line, tow ropes, viroven fabrics, chem.-resist. powd. coatings, extruded automotive fuel/hydraulic hoses, gears, cams, bearings, transparent pkg. fiims vise, control agent in cosmetics food/... 

To examine the further influence of introducing variable chemistry surface pretreatment with ozone, atmospheric plasma trials were performed on an Enercon atmospheric plasma pilot line. The extrusion coating trial runs were performed on a Lyondell Equistar Millennium Petrochemical extrusion coating pilot line. Eor all extrudate trials, a LDPE film was coated onto OPP and PET film. The samples were prepared and tested according to ASTM test method E88. The heat seal tests were made on a heat seal machine using a pressure p = 206.8 kPa and a dwell time T= 1 s. 

Tin finds widespread use because of its resistance to corrosion, or as foil or to provide protective coats/plates for other metals. Properties of lead which make industrial application attractive surround its soft, plastic nature permitting it to be rolled into sheets or extruded through dies. In the finely-divided state lead powder is pyrophoric in bulk form the rapidly-formed protective oxide layer inhibits further reaction. It dissolves slowly in mineral acids. Industrial uses include roofing material, piping, and vessel linings, e.g. for acid storage. 

Fig. 11. Wire-coating line A, unwinding of wire (payoff) B, straightener C, preheater D, extruder E, water trough F, tester G, capstan (puller) and H,...

Most of the polymeric-based layers are applied using extrusion technology the main equipment is the extruding coating line (see Polymer processing). 

To overcome weld line problems, the cross-head tubing die is often used. Here, the die design is similar to that of the coat-hanger die, but wrapped around a cylinder. This die is depicted in Fig. 3.17. Since the polymer melt must flow around the mandrel, the extruded... 

Many different processes are used to coat or laminate there are literally hundreds of different processes used just to coat materials (Table 5.4) (Chapter 10). An important coating method involves the extruder, particularly for long runs. The extruded dedicated fast lines are used since they provide quality controlled products and are very cost effective. 

The usual die used is a crosshead with a 90° angle between the wire line and the extruder body axis (Chapter 17). With this setup, the entire length of the extruder projects sideways from the coating lines. To help melt flow from developing dead spots in the melt channels, 30° or 45° crossheads can be used. They provide a more streamlined interior and the extruder location is better adapted to some plant layouts. They are sometimes preferred when processing PVC because of the streamlining and better control of the melts heat profile. Most dies are subjected to very high internal pressures since the uncommon pressure in the extruder barrel of over 5,000 psi (35 MPa) is required. 

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