SDK Develops Normal-Temperature-Curing, Non-Styrene Vinylester Resin Aqueous Emulsion

Environment-Friendly Chemical-Resistant Emulsion for Lining Application

Showa Denko (SDK) has developed styrene-free vinylester resin which forms aqueous emulsion^** and cures at normal temperature. SDK will start shipment of its samples in this October. This new product has high corrosion resistance that protects concrete from corrosive condition caused by mixture of organic and inorganic acids, cures at normal temperature, and achieves the safety of work environment. The new vinylester resin is suitable for water-proofing and corrosion-proofing treatment of underground cesspits of buildings (building-pits), drainage facilities, and sewage facilities of farm villages.

Owners of office buildings, hotels or shopping malls have legal obligations to equip their facilities with underground cesspits to temporarily store and treat sewage if a facility releases it more than a certain amount. From decomposed sewage or wastewater in these cesspits, inorganic acids including hydrogen sulfide or organic acids including acetic acid and valeric acid may be produced, and these acids accelerate corrosion of concrete.

If we want to protect concrete from a corrosive condition, we must apply high-corrosion- resistant lining such as vinylester resin or organic-acid-resistant epoxy resin to concrete. On the other hand, when we apply conventional vinylester resin which contains styrene to concrete, we must have measures to prevent fire, poisoning, and control odors. When we use organic-acid-resistant epoxy resin, though that does not contain styrene, we must introduce safety measures for workers including rash preventing measures.

Under these circumstances, SDK has been studying chemical methods to give high-chemical-resistance and aqueousness to non-styrene corrosion-resistant materials, making the most of the Company’s knowledge of corrosion-resistant lining and emulsification technology both of which the Company has been fostering over many years. Conventional non-styrene vinylester resin has low chemical resistance. Moreover, if we want to make aqueous emulsion of resins, we generally have to introduce many hydrophilic components to base resins’ structure, which make it difficult for us to maintain water resistance of those resins^***. However, the non-styrene vinylester resin aqueous emulsion SDK developed this time has realized high chemical resistance and water resistance equivalent to conventional vinylester resins, making the most of the Company’s original resin-design and emulsification technologies. In addition, the new vinylester resin can cure at normal temperature and form high-corrosion-resistant coating on concrete, as conventional vinylester resins do.

The new vinylester resin not only has high corrosion resistance and normal temperature curability but also realizes safe work environment. Making the most of this new product, SDK proposes a method of lining with superior work environment, less odor, and easy handling of resins. SDK will continue contributing to infrastructure construction and maintenance, the demand for which is expected to grow both at home and abroad.

^*Non-styrene vinylester resin: Vinylester resin that does not use styrene as reactive monomer. Ordinary vinylester resin is made from vinylester (polymer), diluted and dissolved with styrene (monomer) to be resinified. In the process to synthesize non-styrene vinylester resin, acrylic ester is used as reactive monomer. Organic-solvent-based resin cures after volatilization of the solvent. However, aqueous resin cures after drying of water at normal temperature.

^**Aqueous emulsion of resin: Emulsion of hydrophilic-component-added resin molecules, dispersed in water. When we paint aqueous emulsion of resin, we do not need viscosity adjustment through dilution with styrene.

^***Water-resistance of resins:
Generally speaking, when hydrophilic components of resins absorb water, deterioration by moisture and changes in weight tend to occur.