Antifouling

Marine biofouling is the result of the growth of organisms on natural and artificial structures immersed in sea water. It causes serious problems in the shipping industry, in aquaculture and in cooling systems of power stations. Therefore, antifouling products are of significant economic importance. 

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Antifog agents Antifoggants Antifolate TS inhibitor Antifouling agents Antifreeze... 

Table 13 shows some of the developmental products that have EPA appHcations pending and may be available in the near future. Sea Nine is a variation on the very successflil isothiazolone chemistry. It is claimed to be an improvement over metallic actives used for antifouling paint and wood preservation (46,47). Decylthioethylamine and its water-soluble hydrochloride are claimed to be especially effective at controlling biofilm in cooling water appHcations (48—50). The hydroxymethylpyra2ole shown is also suggested to have properties that are well suited to the protection of aqueous products or emulsions (51,52). 

Trade name. Sea Nine used as a marine antifoulant. Trade name, XV-40304-OIL used for cooling water. 

The advantages claimed for organotin polymer-based antifouling paints include constant toxicant deHvery vs time, erosion rate and toxicant deHvery are controUable, no depleted paint residue to remove and dispose, 100% utilization of toxicant, polishing at high erosion rates, surface is self-cleaning, and function is continuously reactivated. 

Vinyl acetate polymers have long been used as chewing gum bases. They have been studied as controUed release agents for programmed administration of dmgs and as a base for antifouling marine paints (166,167). 

Disinfectant Formulations and Sterilization. Hundreds of appHcations covering disinfectant compositions using sodium chlorite have been described in U.S. and foreign patents. Some examples of these are as antimicrobial additives for latexes (166), marine antifouling agents (see Coatings, marine) (167,168), antimildew detergent compositions (169), toothpaste and solution compositions for prevention and treatment of periodontal oral disease (see Dentifrices) (170—172), and compositions for the disinfection of contact lenses (qv) (173). 

Epoxy and polyester systems filled with flake glass provide a finish that is tough and resistant to abrasion. One commercial system is filled with copper flakes to provide intrinsic antifouling action. These systems are apphed at a total dry film thickness of about 625 p.m and are used on pleasure boats. 

U.S. MiHtary Specification DOD-P-24647, Paint, Antifouling, Ship Hull, Mat. 22, 1985. 

Metal Linoleates and Resinates. The calcium and cobalt salts of Hnoleates and resinates are used chiefly as components of metallic driers used in printing inks. Copper Hnoleate [7721-15-5] is used in antifouling paints for marine use (4). 

As an additional antifoulant measure, SHEs have been coated with a phenolic hning. This provides some degree of corrosion protection as well, but this is not guaranteed due to pinholes in the lining process. 

Despite the attractions of economic forces driving environmental protection, some cautions and failures have been noted. Firstly, the export of hazardous waste to countries where costs for treatment are lower enhances environmental risks during transport and has the potential for transboundary export in the event of pollution. At the same time, the loss of raw material may deprive the home market of an adequate supply of feedstock for the home-based industry. Secondly, there is considerable scepticism that self-regulation of TBT-based antifoulants could be achieved in a timely manner by the shipping industry. This is an instance where the cost benehts to one industry are born by another commercial sector, notably aquaculture. Thus, protection of the marine environment is likely to be aided by economic factors but the role of government, via taxation and standard setting, is not likely to be usurped. Public education and, in turn, pressure, can promote and support corporate environmentalism. 

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