WACKER recently announced that technology service provider TÜV Nord has approved its 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. According to WACKER, 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 consist primarily of a silicone polymer that cures at room temperature to form a rubber-like elastomer, plasticizers, 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 Müller-Rochow process in order to produce a mixture of various methylchlorosilanes. These, in turn, serve as starting products for silicone production. WACKER reports that it uses methanol derived both from fossil raw materials and from biomass, which makes no difference in chemical terms since the molecule is identical with respect to its structure and properties. 

The mass balance method reportedly 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. WACKER uses this method for manufacturing biomethanol-based silicone products for the textile, paper, and consumer goods industries.

TÜV Nord has extended its certification to WACKER’s production of silicone sealing compounds. In this case, the certification meets the requirements of the new REDcert² standard. This standard covers not only all of the organic raw materials for silicone manufacturing, it also encompasses all of the other organic components of the formulation. This serves as verification that WACKER’s silicone sealing compounds are 100% free of fossil raw materials. To qualify, purchased raw materials must have been sustainably manufactured from biomass, and all of the required starting materials must have been obtained from certified sustainable sources. The volumes of raw materials needed for product manufacturing undergo regular audits as part of an annual recertification process.

“Ecological and sustainable construction plays a key part in global efforts to protect the climate,” said Robert Gnann, president of the WACKER SILICONES business division. “Successful certification of our mass balance method makes us the first company to supply ready-to-use sealing compounds based on non-fossil raw materials. That’s good news for our customers, who can likewise declare that the biomethanol-based sealants they purchase from us preserve natural resources and contain no fossil raw materials.”

According to Laurent Morineaux, head of the company’s Construction Silicones business unit, the new certificate underpins WACKER’s ongoing and strong commitment to sustainability. “Sealants are among the most high-volume silicone products in our portfolio,” he said. “Introducing products entirely based on biomethanol does more than just make our portfolio more sustainable. We are also making a substantial contribution toward greater sustainability in the construction industry, and that benefits our customers as well.” 

For more information, visit www.wacker.com. Details regarding the REDcert² certification system are available at www.redcert.org/en. TÜV Nord is online at www.tuv-nord.com.