Green tyre

Introduction by Michelin et Cie. of the "Green Tyre", with a silica-reinforced tread, rather than with carbon black, and using solution-polymerised rather than emulsion-polymerised SBR, for 30% reduced rolling resistance and corresponding energy saving... 

As stated previously, precipitated silica is being used to replace the carbon black filler in so-called green tyres where it has been shown to reduce rolling resistance [43-46], and so help to reduce fuel consumption. Since the late 1960s, silica has been used in combination with resin systems and at that time PPG introduced a system that consisted of HI-SIL hydrated silica, resorcinol and hexamethylene tetramine (HRH). Initially it was used chiefly for bonding various rubbers to textiles, but such systems have found increasing use in wire coat and belt compounds. 

This article reports that insufficient conductivity of Michelin s green tyres is being investigated as a possible cause of an electrostatic build-up on Opel Astra compacts, that has led to flash fires during fuelling, all of which have occurred in Germany. Details of the situation are provided. 

C. R. Stone, K. H. Menting and D. M. Hensel, Improving the silica Green Tyre tread compound by the use of special process additives , Schill Seilacher, ACS Rubber Division Meeting, Orlando, FL, September (1999)... 

Some studies have looked at producing useful products, effectively fillers, from waste rubber by using methods that use a partial pyrolysis approach. Silica is being used as a part replacement for carbon black as a filler in the production of green tyres . As this practice increases, there will be a corresponding increase in the total recoverable inorganic fraction from waste tyres, and so this recycling route could become more attractive. Examples of partial pyrolysis processes are described below. 

Ivanov and Mihaylov [3] in Bulgaria have described how a solid product was obtained from green tyre treads by a partial pyrolysis route, which, when analysed by infrared spectroscopy and X-ray fluorescence (XRF) spectroscopy, was found to have the composition shown in Table 8. ... 

Table 8.2 Composition of the solid product formed by pyrolysis of green tyres [3] ...

With the advent of Green tyres the use of silica has significantly increased. A typical Green tyre formulation for passenger tread is shown in Table 38. In order to achieve high temperature cure, the use of Perkalink 900 has been reported (26). 

Table 38 Green tyre formulation -passenger tread ...

Tyres are normally cured in a modification of the compression mould where a bladder or an inflated airbag forces and holds the green rubber stock of the tyre against the mould surface during vulcanization. This force reproduces the design of the tyre tread and the heat from the steam is introduced into the bladder to effect the vulcanization. Small size rubber expansion joints used in piping systems are moulded by compression moulding... 

Keywords Natural rubber, Hevea brasiliensis, cultivation, modification, primary processing, manufacturing techniques, pneumatic tyre, non-tyre products, vulcanization, green commodity... 

NR is one of the world s important natural resources and sihca is considered environmentahy friendly upon disposal. Thus, in terms of sustainability development, development of sihca-fihed NR nanocomposites opens new opportunities for producing green materials/products such as tyres. Traditionally, carbon black is preferred over sihca as fiber in tyres due to the challenge in dispersing sihca in rubber compounds. With the new development, e.g. in situ sol gel silica, admicellar polymerization and polymer-encapsulated sihca, the applications of nano-silica in NR and modified NRs are widened. 

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