Construction Fixings

German-based WACKER Chemie AG has achieved TÜV approval of its resource efficient manufacturing method for silicone sealants according to the new REDcert2 standard.

WACKER’s approach involves determining the mass fraction of raw materials and auxiliaries derived from fossil-based resources and offsetting this with methanol produced from biomass. WACKER says it is the first chemical company to produce the organic components of its sealants exclusively on the basis of plant-based materials instead of raw materials derived from petrochemicals. Silicone sealants are important materials in construction and installation projects and are primarily used for the bonding and sealing of joints.

WACKER states it is also the first company to apply a certified mass balance method when manufacturing silicone sealing compounds. Silicone sealants consist primarily of a silicone polymer that cures at room temperature to form a rubber-like elastomer, plasticisers, fillers and additives. Apart from silicon, which is manufactured by reducing quartzite with coke, an important raw material for manufacturing the polymer is methanol. The compound is first converted to methyl chloride, which then reacts with elemental silicon in the commonly known Müller-Rochow process in order to produce a mixture of various methylchlorosilanes. These, in turn, serve as starting products for silicone production. WACKER uses methanol derived both from fossil raw materials and from biomass, which, however, makes no difference in chemical terms, since the molecule is always identical with respect to its structure and properties.

The mass balance method takes advantage of that. If methanol from both plant and fossil-based sources is used within an integrated production system, the portion of raw materials derived from biomass can be determined and explicitly allocated to individual sales products. The approach is comparable to the green electricity certification system used in Germany.