Mixing of rubber

Continuous mixing of rubber compounds is a very promising method in order to obtain a more consistent quality at very high levels (e.g., better dispersion and far better consistency). 

Internal Mixing of Rubber, J.C. Lupton Failure of Plastics, S. Turner, Queen Mary College. 

Compounding and mixing of rubber with proportionate amounts of various ingredients which when compounds are vulcanized yield the desired properties. 

Z. Tadmor, Passage Distribution Functions and Their Application to Dispersive Mixing of Rubber and Plastics, AIChE J., 34, 1943 (1988). 

Grossman RF (1997) The mixing of rubber. Chapman and Hall, London... 

Schwartz (2001) and Haberstroh and Linhart (2004) note that rubber mixing processes are inherently extremely complex and use artificial neural networks to evaluate rheometric properties and process models for mixing of rubber compounds. 

Physics of mixing. The mixing of rubber compounds is a very complex operation about which it is difficult to have an overall and clear understanding (3-5). However, it is useful to consider that four basic physical operations take place during the mixing cycle (I). 

M. FONT - "Mixing of Rubbers" - RAPRA, Shrewsbury, England (1977). 

Parkes was bom in 1813 and was apprenticed as a brass-founder. He became active in the youthful rubber industry and in 1843 patented a waterproof fabric, a patent he sold later to Charles Macintosh. The waterproofing of fabrics was naturally a major earfy use of natural rubber, which was obtained at the time from trees in the South American jungle. The unpleasant tackiness of the early products was eliminated with the discovery by Goodyear and Hancock in the 1840s of the vulcanizing effect of sulfur. At first the sulfur was merely dusted on the surface, but this was soon to be followed by mechanical mixing of rubber and sulfur. The interest of Parkes in the infant rubber and plastics industry is symbolic of the scientific and industrial relationship which has always existed between them. 

The TMS rheometer has been used to study mould release in rubbers. It contains a biconical rotor (representing the mould surface). The polymer is placed in the transfer chamber, injected around the rotor and cures in situ. Fig. 1. The shear stress required to free the rotor is taken as the mould-sticking index . The rheometer has the advantage that small experimental mixes of rubber can be evaluated. Further, the rotors are easily changed, so as to evaluate changes in mould surface, and the parted surfaces are amenable to examination by XPS and other methods of surface analysis. The obvious disadvantage is that access to special equipment (the TMS rheometer) is required. The same basic concept could be adapted for the study of mould adhesion of non-elastomeric polymers. 

The continuous mixing of rubber compounds is possible if the components of the mix are all in granular, powder or liquid form. 

Funt, J. M., Mixing of Rubbers, RAPRA Publications, Shawbury, UK, 1977. 

MIXING OF RUBBER AND VISCOELASTICITY. IV. VISCOELASTIC CHARACTERISATION OF COMPOUND... 

Material developments in the rubber industry are outside the scope of this report, other than where they may affect the mixing of rubbers. Where material developments impinge on mixer design, for instanee where one partieular design is favoured for teehnical reasons over another, then referenee may be made to particular materials. 

CONTINUOUS MIXING OF RUBBER WITH THE RING EXTRUDER... 

MACHINE CONCEPT SCREENING FOR CONTINUOUS MIXING OF RUBBER COMPOUNDS... 

A description is given of a novel planetary roller extruder developed by ENTEX for the continuous mixing of rubbers and plastics. The efficiency of this extruder for compounding rubbers is demonstrated by a comparison with a discontinuous internal mixer. 

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