Sabo and Sunny Wealth Offer Solutions for Polyurethane Systems

Neslihan Şolt / Chemical Engineer - Polymer Additives Department - Üçgen Pigmentler & Polimer Katkıları Ticaret ve Sanayi Anonim Şirketi

Polyurethanes are versatile polymers. They have a broad application spectrum including adhesives, fillers, paints, reactive injection molding components, thermoplastic parts, elastomers and rigid/flexible foams. Polyurethanes possess impressive performance characteristics and the service life of polyurethane products can be significantly extended through the use of appropriate stabilizers. The selection of a suitable stabilization system depends on specific production conditions, the final use environment and the fundamental degradation mechanisms of polyurethane materials. Degradation of both polyol and urethane components causes changes in the physical and mechanical properties of polyurethane. Urethananes are susceptible to degradation through free radical pathways when exposed to heat and ultraviolet light. Sabo and Sunny Wealth polymer additives, which we represent, offer solutions that facilitate the processing of polyurethane products and extend their service life. The use of primary antioxidants by Sunny Wealth, such as Sonox, prevent the formation of free radical species and hydroperoxides in polyol during storage. HALS produced by Sabo – such as Sabostab – protect polyurethanes against UV light-initiated degradation. UV absorbers – such as Sabostab UV 312 – prevent the onset of degradation by absorbing ultraviolet light reaching the surface of the polyurethane material.

Applications

Thermoplastic Polyurethane (TPU)

Thermoplastic polyurethanes are among the most versatile polymers with elastomeric properties. During TPU production, process stabilizers such as Sonox 1010 and Sonox 2450 can be used to protect the polymer against degradation. Due to their versatility, TPUs are used in application areas requiring both heat and UV stabilization. For advanced final use stability, heat stabilizers such as Sonox 1135, Sonox 2450 or Sonox 1010 can be used. Light stability can be achieved through the use of HALS alone or in combination with UV absorbers – Sabostab UV 312.

Reactive Injection Molded Polyurethane (RIM)

Polyurethane parts can also be produced using the RIM (reactive injection molding) method. Raw materials are injected into the mold where polymerization takes place. Depending on the final use of the product, advanced light or long-term thermal stability may be required. In particular, automotive parts have light stability requirements due to performance specifications. To achieve this, UV absorbers – Sabostab UV 1 – are used together with HALS and/or antioxidants.

Polyurethane Foams

Polyurethanes can be foamed and formed into flexible, rigid or surface foam shapes. Each type of these applications requires specific stabilizers. During the production of flexible cushioning foams, the exothermic foam resulting from the polyol/isocyanate reaction causes yellowing in the center of the foam. The reason this is observed most frequently in flexible cushioning foams is the size of the foam. Since polyurethane foams are good insulation materials, the interior of the foam can remain hot for hours, which increases the risk of center yellowing. Rigid and surface foams – due to their limited size – show less tendency to yellow than flexible foams. Phenolic antioxidants added to the polyol (Sonox 1076, Sonox 1135, Sonox 1010) provide effective protection against yellowing. In selecting additives to be used, foaming techniques and final product properties should be taken into account. Antioxidants are used to protect the urethane against degradation that may occur during processing and final use, and to protect the polyol against oxidation that may occur during storage and transport. Many final products from rigid and surface foam applications are used in outdoor environments. For this reason, light stabilizers are required to provide ultraviolet protection.

Polyurethane Fibers

Polyurethane fiber – commonly known as spandex – is a synthetic elastomeric fiber. Its stretchability and flexibility make PUR fibers an ideal material for swimwear, hosiery and sportswear. In the production of polyurethane fibers, antioxidants are generally required (Sonox 2450, Sonox 1076). When advanced performance is demanded by the consumer, ultraviolet light absorbers (Sabostab UV 312) can be used together with HALS (Sabostab UV 62).