Rubber processing lines

Nonlinear Viscoelasticity along Rubber Processing Lines.830... 

NONLINEAR VISCOELASTICITY ALONG RUBBER PROCESSING LINES... 

The target output capability for such a multiplex extrusion line is 25,000-30,000 treads per day. This results in a rubber processing capacity of 10,000 kg/h. 

Batch mixer are the oldest type of mixer developed for rubber processing, and they are still widely used. Batch mixers are very versatile because operating conditions can be varied during the cycle, additives can be added at an optimal time sequence, and good temperature control can be maintained furthermore, they are available in a very broad range of sizes and, if need be, can be incorporated in continuous lines. 

Du Font s major contribution to the country s war effort in World War 1 was the manufacture of explosives. By the time World War 11 erupted, explosives was just one of the many Du Pont products needed in the war effort. The insatiable appetite of the war machine imposed numerous demands on technical personnel to build new process lines (over 50 plants were built) in record time and to develop specialty products by yesterday. Chemical engineers played a key role in meeting these demands. Since natural rubber was no longer available, plants to manufacture synthetic rubber such as neoprene had to be built. Rayon and nylon were used in tire cord. Industries producing combat equipment needed heavy chemicals. The emergence of air power required special chemical materials such as plastic enclosures. 

Rubber-to-Metal Bonding. In the Ebonit or hard rubber process [76], the bonding agent is a reaction product of natural or synthetic rubber with 30-40% sulfur, which is thermoplastic in character, adheres firmly to metal, and provides for good adhesion to soft rubber. This process is still in use today in the lining of vessels and, to a certain extent, in the manufacture of large-diameter rolls. 

Fig. 1. Selection processes of Rubber-Line-Sweep, Line-String and Rubber-band box (a) Rubber-Line-Sweep dragging cursor extends a rubber-band line which is used to sweep targets to select them (b) Line-String drawing a stroke to string targets to select them.(c) an irregular layout of targets can not be completely included by a rectangle.

Chapter 16C Compression, Transfer and Injection Molding of Specialty Elastomers by Dr. Robert W. Keller will give the rubber compounder an excellent view of the considerations necessary in the molding operation in the factory. This is only one aspect of rubber processing, but similar approaches are needed for other processes such as extrusion, calendering, machine, and hand building of hose, belts, rolls, tank, and pipe linings, and so on. 

Initially, all of the SBR polymer known as GR-S produced during World War II was by the batch process. Later, it was thought that a higher volume of polymer would be needed for the war effort. The answer was found in switching from batchwise to continuous production. This was demonstrated in 1944 at the Houston, Texas, synthetic mbber plant operated by The Goodyear Tire Rubber Company. One line, consisting of 12 reactors, was lined up in a continuous mode, producing GR-S that was mote consistent than the batch-produced polymer (25). In addition to increased productivity, improved operation of the recovery of monomers resulted because of increased (20%) reactor capacity as well as consistent operation instead of up and down, as by batchwise polymerisation. 

Tank material A mild-steel (MS) tank, with a wall thickness of 4-6 mm, and having an acid-proof lining of FRP (fibre-reinforced plastic), rubber or PVC will be suitable for this purpose. A healing arrangement, even if a cold process is adopted, will be ideal for... 

British Standard Code of Practice C.D. 3 003 Linings of Vessels and Equipment for Chemical Processes. Part 1 Rubber, Part 2 Glass Enamel, Part 3 Lead, Part 4 P.V.C., Part 5 Epoxy Resins, Part 6 Phenolic Resin, Part 7 Corrosion and Heat Resistant Materials, Part 8 Precious Metals, Part 9 Titanium and Part 10 Brick and Tile... 

The production of a rubber lining includes the preparation of the rubber compound followed by processing to form the lining sheet, substrate preparation, lining application, vulcanisation and inspection. All these stages require thorough quality control, especially compound manufacture and sheet preparation, as chemical resistance depends on satisfactory dispersion of the individual ingredients and undetected flaws in the sheet will cause problems in service. 

The lining sheet is prepared by calendering in thin plies up to 1 mm in thickness, followed by combining the individual layers on the calender to form a finished sheet, usually between 3 mm and 6 mm thick. Alternatively, lining sheet can be manufactured by the roller die process in which the sheet is extruded and then passed through rollers to give the finished thickness. Extrusion is also used for the preparation of unvulcanised rubber tubes suitable for lining pipes up to 200 mm in diameter. 

The calender was developed over a century ago to produce natural rubber products. With the developments of TPs, these multimillion dollar extremely heavy calender lines started using TPs and more recently process principally much more TP materials. The calender consists essentially of a system of large diameter heated precision rolls whose function is to convert high viscosity plastic melt into film, sheet, or coating substrates. The equipment can be arranged in a number of ways with different combinations available to provide different specific advantages to meet different product requirements. Automatic web-thickness profile process control is used via computer, microprocessor control. 

---