Abstract: A method is disclosed for controlling the elution rate of a stainproofing agent from treated fibriform or corded materials, prior to immersion in seawater, which method comprises treating the fibriform or corded material with a composition which comprises 4,5-dichloro-2-n-octylisothiazoline-3-one, a homo- or copolymer or a (poly)oxyethylene (meth)acrylate ester, one or more of a dialkylpolysulfide, polybutene, xylene/formaldehyde polycondensate and a nine-carbon aromatic hydrocarbon/formaldehyde polycondensate, and an organic solvent. The treated material is also disclosed.

Abstract: As an object and a use of an undersea antifouling treating composition provided by the invention, in order to prevent the adhesion of sessile organisms over a long period of time, the antifouling treating composition is immersed in fish nets for culturing, trapping and the like immersed in sea for a long time and materials such as rope and the like supporting these nets, a net for preventing invasion of jellyfishes at an intake port for cooling water, a curtain for the prevention of marine pollution used in seaside working and the like.

Abstract: Compositions including the dithiocarbamic acid derivative having ##STR1## group and at least one organo-tin compound selected from the group consisting of polymers having recurring units containing organo-tin, copolymers which are copolymerized with acryl compounds or vinyl compounds and organo-tin chemicals of ##STR2## are extremely effective for preventing the adhesion of marine organisms including marine microorganisms. This effect of the said composition is enlarged in the presence of copper compounds. R.sub.1, R.sub.2, and R.sub.3 represent an alkyl or phenyl, cycloalkyl group: Z; monovalent functional group containing sulphur or oxygen: and W; divalent functional group.