Selin’s soccer boots, Ines and Andi’s waterproof clothing and Lara’s sneakers all have one thing in common: Chlorine is used in their manufacture to some extent. The versatile chemical element is produced in chlor-alkali electrolysis plants from thyssenkrupp Industrial Solutions, marking the start of a manufacturing chain for a wide variety of products that we can no longer imagine life without – including trendy sneakers.
Every year, the plants built by thyssenkrupp produce around 39 million tons of chlorine, which among other things forms the basis for the so-called MDI process for the manufacture of methylene diphenyl isocyanate. These compounds with the complicated name are an intermediate product for the manufacture of polyurethane (PU) – the Swiss army knife of the plastics world, as it were. Depending on the exact type of crosslinking within the polyurethanes, they result in thermosetting plastics, thermoplastics, elastomers, rigid and flexible foams or casting resins.
In shoe production PU can be found in materials for soles, heels and uppers. In the manufacture of outdoor gear and clothing, polyurethane has allowed the recently discredited per- and polyfluorinated chemicals (PFCs) to be eliminated from production shops. PU is a much more eco-friendly alternative for making outdoor clothing dirt and water resistant.
Chlorine – a key component
And that’s not all: The diatomic chlorine molecule Cl2 can be processed in a wide variety of ways, making it a key component of numerous important chemical compounds. Chlorine is generated by electrolysis: An electric current is passed through a sodium chloride solution – also known as saline solution. Gaseous chlorine forms at the anode, while sodium hydroxide and hydrogen form at the cathode. Thanks to its innovations in electrolysis, thyssenkrupp Industrial Solutions has revolutionized chlorine production: BiTAC electrolyzers, a filter press and the BM 2.7 single element are combined to enable unique zero gap technology in which the gap between the cathode and anode is virtually eliminated. As a result energy consumption can be reduced to around 2,000 kWh per ton of sodium hydroxide (NaOH) at 6 kA/m2. In chlorine electrolysis using an oxygen depolarized cathode (NaCl ODC technology), energy consumption can be reduced by a further 400 kilowatt hours by adding oxygen. This allows energy savings of up to 25% for an even better carbon footprint. These innovations can be combined and are already in use in numerous plants around the world – from small-scale chemical plants to gigantic chlor-alkali electrolysis complexes with capacities exceeding 800,000 tons of sodium hydroxide per year. thyssenkrupp is focused on outstanding quality with a view to cost efficiency, safety and environmental protection.
Countless products are reliant on the processing of these chlorine compounds. From pharmaceuticals, pigments and paints, corrosion protection, insulation and sealing materials, to bristles for toothbrushes and cosmetics, to bulletproof and fireproof clothing. There is virtually no sector of industry that does not use chlorine in one form or another.
Almost 90% of pharmaceutical products also need chlorine. Virtually all drinking and process water in the USA is disinfected with it. To eliminate germs such as salmonella and coli bacteria, the material is a key factor in the manufacture of cleaning products and disinfectants for restaurants and kitchens. In the automotive industry chlorine and caustic soda play an important role in the production of airbags, safety glass and seat cushions. And in the home and garden sector, chlorine is a key component in the production of thermal and power cable insulation materials.