Granulate rubber

Figure 2. Product composition from fluidized-bed pyrolysis of granulated rubber tires, plotted as weight percent vs. temperature...

Rubber products pose a special problem in the environment, and their dumping in landfills usually requires a special fee. Discarded in piles or buried, they occasionally catch fire and produce noxious gases. In developing countries, many used or damaged automobile tires are repaired or disassembled to make other products. Granulated rubber produced from... 

The rotacurrent dryer can handle particulate and non-sticky products such as aluminum silicate, copper powder, pyrite ore, charcoal, granulated rubber, chopped straw, detergents, and the like [75]. Performance data on the rotacurrent dryer are given in Table 21.21. 

Typical materials that can be used in these devices are abrasive grit, agri-chemicals, cat litter, coarse powders, grain, industrial minerals, industrial sand, pet foods, plastic granules, rubber crumb, salt, seeds and sugar (A.T. Sack Fillers Ltd 2006). 

There can often be some debate regarding the definition of rubber granules, rubber powder and so on, and the protocol provides some assistance here by providing the definitions shown in Table 6.1. 

In another case where the twin-screw extruder was used, the rubber and plastic were melt mixed with all ingredients in a similar manner as described in blend compositions for static vulcanizations. The product was then dumped, cooled, and granulated. The premixed granules were then fed into a twin-screw extruder where a very narrow temperature profile was maintained with a relative high compression (2 1), and the screw speed was adjusted depending on the final torque and the flow behavior of the extruded stock. The stock was cured by shear force and temperature enforced by the twin-screw extruder. The dynamically crosslinked blend was taken out in the form of a strip or solid rod to determine the... 

Plasticized white phosphorus (PWP) was found to be the most promising development for control of the fragmentation of P and pillaring of die smoke. It consists of an intimate mixt of granulated WF in a viscous rubber soin. The material burns more slowly and the particles... 

The technique of passing a gas into a solid which is in the form of tiny granules and thus making the solid behave as if it were a dense, viscous liquid. Fluidised materials may be easily piped from place to place, but a particular application in the rubber industry is the vulcanisation of extruded sections. See Fluid Bed Vulcanisation. Fluorinated Elastomers... 

Unvulcanised rubber in the form of granules. It is used for dissolving in hot bitumen for making the surfaces of so-called rubberised roads Power Factor... 

Rubber compounds are colored with powder pigments and increasingly with granulated pigment preparations, known in the rubber industry too as master-batches. 

The continuous mass process is divided into 4 steps rubber solution in styrene monomer, polymerization, devolatilization and compounding. In 1970 N. Platzer (40) drew up a survey of the state of the art. Polymerization is divided into prepolymerization and main polymerization for both steps reactor designs other than the tower reactors shown in Figure 2 have been proposed. Main polymerization is taken to a conversion of 75 to 85% residual monomer and any solvent are separated under vacuum. The copolymer then passes to granulating equipment, frequently through one or more intermediate extruders in which colorant and other auxiliaries are added. 

The tests on DPE suit material and wood addressed size-reduction and material-transport problems identified during the Demo I testing (NRC, 2000a). DPE suit and butyl rubber simulant materials were shredded in a dedicated granulator, cryogenically cooled in a cryo-cooler with an internal screw conveyor, and reduced in a cryocooled hammer mill. No materials contaminated with agent were tested. 

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