We specialize in manufacturing FDN-A,B,C of sulphonated naphthalene formaldehyde.Our production capacity is 300,000 tons/year. SULPHONATED NAPHTHALENE FORMALDEHYDE1.Product GeneralFDN-A ,FDN-B,AND FDN-C Superplasticizer is a dry powdered admixture. It is produced through such a process: 1) sulphonating refined naphthalene with sulfuric acid, 2) condensing with formaldehyde, 3) neutralization, and ...