Rubber goods other than tires

Non-tire rubber applications correspond to the so-called industrial rubber sector, which, in terms of manufacturing, involves a number of employees of the same order of magnitude as that of the tire sector (52 and 48% respectively out of a total of 58,000 employees in France in 2011 (doc. SNCP). On the other hand, unlike the tire industry, the industrial rubber business is spread across a large number of companies, both small and large.

In descending order of importance, industrial rubber covers: automotive (50%), non-automotive transport (14%), industrial equipment (12%), medical (7%), construction (7%), semi-finished products (5%), adhesive tapes (4%), sports and leisure (1%) (doc. SNCP).

In the automotive industry, for example, it faces competition from thermoplastic elastomers (TPEs), which are simpler to process, since the pellets marketed by producers are fed directly into injection molding machines or extruders. As in the case of rubbers, there is no mixing and vulcanization stage, not to mention the necessary prior formulation development required to achieve the performance levels demanded by the intended application and spelled out in the specifications. However, the advantage of rubbers over TPEs lies in their unrivalled properties, such as high elasticity, low compression and tensile set, fatigue resistance, tear strength...

What's more, certain special rubbers (silicones, fluorocarbons) can withstand high temperatures and chemicals, making them indispensable in high-performance applications such as aeronautics, offshore, turbo hoses, etc. Their limitation is their cost (orders of magnitude in [Doc. AM 8 605]), which far exceeds that of mass-market rubbers (natural rubber, SBR, EPDM).

Rubber manufacturers prepare their own "mixes" using specific tools (internal mixers and cylinder mixers). They therefore have their own formulas and their own mixing parameters, developed and constituting their know-how. The basic elastomer is gum, which is marketed by major groups in the case of synthetic rubbers – Lanxess, Zeon, Du Pont, Exxon... natural rubber is produced in descending order by Thailand (31%), Indonesia (27%), Malaysia (9%), India (8%), Vietnam (7%) and China (6%) – the remainder being produced in Africa and Brazil (doc. SNCP). In addition to gum, rubber formulas contain :

• fillers (usually carbon black or silica);

• vulcanizing agents;

• oils ;

• various processing and protective additives.

The second point that characterizes the rubber industry is the need to vulcanize it to give it better properties for use, which calls for...