CA2192395A1 - Biocidal compositions - Google Patents

Abstract

A synergistic composition of biocides for the preparation of anti-fouling paint preferably containing at least one of the group of 3-iodo-2-propylyn-buty carbamate, 3-iodo-2-propynyl-cyclohexyl carbamate, 3-iodo-2-propynyl phenyl carbamate, 3-iodo-2-propynyl benzyl carbamate, 3-iodo-2-propynyl propyl carbamate and 4-iodo-3-butynyl propyl carbamate and at least one or the group of tributyltin compounds consisting of bis(tributyltin) oxide, tributyltin fluoride, tributyltin methacrylate, tributyltin phosphate and tributyltin naphthenate. Said composition is more effective in protecting ship bottoms or underwater constructions than each component itself.

Description

2~ q239~
.
BIOCIDAL COMPOSITIONS
E~CKCROUND OP TEIE INVI~ WII
1. Field oi the rnventiOn The present invention relates to biocidai ~ np~~ ns, particu-larly those .~ ail h~ a s~ bllc mixture o~ <:a~ ~' and organo-tin biocides userul tor ~ ~1h.g materials exposed to an aquatic This inventlon especially relates to the prevention and inhibltlon o~ ~oulin~ or marine structures such as boat, ship, o~ other vessel hulls, piiings, oil weli drillin~ towers, and the Illte by organisms commoniy round in sea water.
rn a prererred . 1~ t, the present invention relates to a biocidal ~ ~ti-~ c.~ a synergistic mixture ot ~;al -te and tribuqitin biocides. In this prererred t, a marine structure ~s treated by coating the surtace thereo~ with a paint con-taining an organic binder and a blocidaiiy et~ective amount o~ the mixture o~ (1) the s ~ ~ , such as one seiected trom the group consistin~ o~ 3-iodo-2-propynyl propyl ~e 3-iodo-2-p~opynyl buql c~ L - t~, 3-iodo-2-propynyl hexyl Ca~ i 3-lod~2-propynyl ~ a~' ~, 31~2 ~..1.,..~1 phenyl - ~, 3-lodo-2-propynyl benzyl carbamate, 4-iodo-3-buqnyl propyl Ca~ and mi~ctures thereo~, and (2) the tributytin com-pound, sUCil as on~ selected trom the group consistlng o~
bis(tribuqltin) oxide, tributyltin rluoride~ tributyltin -- ~ e~
tributyltin phosphate and tributyltin ~ , and mixtures thereo~. rn another Pmh~iim~r~t a marine structure is treated by coating its surrace with a . ~....lailli~ a biocidaliy et~ec-tive amount o~ either 3-iodo-2-propynyl propyl ~alLamate or 4-iodo-3-butynyl propyl cârbamate or a miYture thereo~.

2. ~escriPtlon of Related Art Slnge~ U.S. Patent 3,923,870 describe~ urethanes of l-halogen-~7~ tit~ted alkynes and their ~ungicidaL actlvity. The compound 3-iodo-2-ptopynyl butyl carbamate (IPBC) (CAS 55406-53-6) described in U.S. Patent 3,923,a''0 is widely used as a ~ungicide ror aqueous and organic ~iolvent based sy~items such as paints and coatings, metai cut-ting iluids, textile and paper coatings, ~nks, plastics, adhesives and the like. Research indicates that IPBC has a promising ef~icacy pro-file against wood destroying otganisms (fungi), having shown low toxic values for common ~ungi. ~ndeed, a unique chdl ~t L~Llc O~ IPBC is Its e~ricacy against both ~lue stain (~ ~...te~) and generai wood destroyine ~ungi (t--' ' ~ t~ at a re~--OLI~ A~r~ At1on rate.
IPBC i~i also known as an al~iclde rOr use in ~re~h water and marine ~"At~ons, see U.K. Patent 2,138,292.
It also is known that or~anic tin; such as those or the ~eneraL rormuia:
(CH3CH2CH2CH2)3 Sn-R4 where R4 is selected rrom (CH3CH2CH2CH2)3SnO, rluoride, chiot~de, phosphate, acrylate ~lat." r,-l-l.LI,~ , hydro~ide, octoate, phthalate, suifate, maleate, rumarOte, laureate, linoledte, atietate, ,_~ il.1....,_t~-, and the IDce can be used iri paints to provide Onti r-aulll.~ property to coOtings appiied to ship hulis to prevent roul-ing ty a~ae and other marine ot6~anisms (pests~.
Th~ prlor art, however, does not provide any indication whether the ~ ' ' o~ the run~iclde IPBC or other related c~; run~,icides with an or6~anic tln compound such as one or more o~ the d~.~ n~ Jt~ltla r~ , wouid t)e usetui ror anti-rouline coatines ror l,lvl~_Lh~ materials e~posed to an aquatic (ee. marine) e.. .Lun~ ~ , such as ship huLls and othe~ under-water~ ,u.~iu-~.
The erowth ot marine or~,anisms on the ,~l parts o~ a shiprs huLi ~ncreases the rrictional resistance ot the huL to passage throu~,h water, leading to increased ruel .~ol~ul.~llua and 'or a reduc-tion in the speed oi the ship. Marine erowths a~ so rapidly ~ 21 92395 that the remedy ot cleaning and repainting as recuireci in drydock is~eneraliy ~v.~ld .~-i too expenslve An aiternative which has been practiced with increasing el~iciency over the years, is to Umlt the extent or ~ouUni~ by applyini~ to the huli a top coat paint incorpo~at-ing anti-~ouUng agents. Ths anti-rouUng a~ents are blocides which are ~reed Irom the surface of the paint over a period or time at a concentration lethai to marine organisms at the hul;i surface. The anti-~ouUng paint faiis oniy when the cvl.o~ Ldth.,. o~ biocide avail-able at the paint sur~ace ~alls below the lethal concentration and with modern paints up to two years of use~ul Ufe is expected.
There are marked ~ tl ~ .c between the requirements ~or biocides in dif~erent ell~lr~ ta, such as antifuni~al agents in house paints, fresh water aii~icides, and ~ ro~ agents ~or marine struc-tures exposed to sea water ~lora and fauna. ~s is i~nown, the miidew or ~uni~us which i~rows on house paints and the Uke, utiiizes the paint medium as a nutrient, or in some cases, the ~..1 .1~ substrate, such as wood, as the nutrient. The myceUa and ~ruiting bodies of the ~ungi contact or penetrate the paint ~ilm and thus, through intimate con-tact with any ~uni~icides in the ~iim (to a iari~e extent regardiess o~
whether the ~ungicides are hi~itiy soluble. sllghtly soluble, or insoluble in water), the rungi are destroyed. In cooUng towers utilizing (resh water, siime and algae may develop it ef~ective ~ ror com-battin~ their ~rowth are not present. ~n the case ot cooiing tower water, the com~ound shouid be highiy soluble. In paints such as exte-rior house paints, ~ g~lad normal exposure to weather, the solubii-ity ot the compound is not as criticai since the paint ~iim is oniy spo-radicalLy exp~xed to iiquid water.
Whiie IPBC and related carbamate ~ are known to exhibit ~ood ~ungicidai and aii~icidai activity, it is not icnown whether these runi~Lcides couid aLso be used in anti ~ ~ coatings in combi-nanon witit i~nown organic tin ~ ~ parncuLarly ~ u~ltlll-type ~ 1~ . to preYent the ~rowth o~ marine organisms ULce aigae, barnacLes, ~ h~ bryozoan, tunicates, hydroids, adherent sUme or other hii~her deYeloped ~., on auiJu~ i sur~aces.
Resuits obtained with anti-~ouUng painu when utiiizin~ iP~C and _, . .. . . . _ _ _ _ _ _ _ _ _ _ _ _ _ .. . _ _ 2l 92395 related ~ , are not y~ rom their er~ac~l~_..~ as general blwlGes, whether against bacteria, ~un~i, Insects, etc. ~t also is not known ir or how lonz the ~ ~' would retain its e ~icacy as an ~ntl ~uuL~ biocide rG- ~-t1nn or whether it might eYen ~e superior in overaLt perrormance as an anti-foulin~ compound ~n com-parison to the ludu~u~uy~l~yl ~;~L - -t~ r~lneC or the l-i~ulyllll~ t by tl~
~ flt1nn~1y, it is not known how the ~ ' t1nn o~ one or more members ~rom each group o~ these ~ u~ would a~ect their overaLt biocidal (anti-~oulin~) activity, ~or example, ir used in paint to protect ship huLls ~rom the growth ot marine organisms. As is always a possibitity when using a r ~~ or chemicals having diverse activities. one or the chemicals may impair or Interrere with the activity o( the other.
From the ~ore~oing, it is apparent that the er~cctl~.,~ or biocidal materials userul in ~ ' ~ rungi, insects, bacteria, and the 18te irl r,u-. aqueous media, and biocides errective in c~mhAttlng ~ungi, slime, and algae in rre3h water systems, carmot be used to pre-dict the er-e~ ~ or these as dllti ruuL~I~ agents in sea water and bracldsh water capabb o~ Y~ Llng marine life such as oarnacles, slime, hydroids, ~gr~ brown relt atgae and the Ltke.
Since the prior art has not disclcsed or sug~ested combining IPBC or its related carbamate ~ r ~-k with or~anic tin c~
and especiaLty th~ d~U.- t.;LuLylthl t~e biocides, the prior art doe~ rlot indicate what amounts or the rungicide IPBC (and it~ related c~ c~ ) and ot the organic tin ~mr~n~1 such as one or more ot the d~U._ ..ut~ tributyltin-type blocides, are required to provide an optimum in anti-rouling .~ cArl~ against al~ae and hi~her developed marine u.~ For similar reasons, it is not known what amounts or IP8C (and its related ca~b~ com-pounds) and or the organic tin compound are needed to obtain the lùlU l~lL.~ erricacy needed ror successrul a~ti ~ùul~.t, marine appLi-cations, or how to ~ormulate an etrective anti-~outant using this biocide ~omh~nAt1nn rn thi-c regard, there is a ~rowing concern about the environ-mentat e~rects caused by using the organic tin biocides at their present commercial leveL as an anti-foulant active ingredient in coating . rcitinnc ~or aquatic (mar~ne) ~ t has been shown that, due to the ~ ri use o~ L~i~u~yl~ll, ty~ mp~llnt~c in partlcular, at Cu~ tlatlu-~ as high asi 20 wt. 96 in paints ror ship bottoms, the poLiution ot :~UI ~ UUIIIlillg water due to leaching has reached such a level as to cause the ~ adatlull ol mussel and shell organismc. These e~ects have been detected along the French-Brit-ish coastline and a similar ei'iect has been con~irmed in US and ~ar East waters. Under the most recent regulatory r~triA-tinnc, with lim-ited ~ c~ pleasure boatsi up to 25 meter_ long are no longer permitted to use antl-loulant paint containint high levels or tributyltin I~Mr J
Research has sh~wn that a_ long as the leaching rate o~ tin can be ~--lnlA ~ at or below about 4 ug/cm2 per day, aquatic li~e does not appear to be a~ected over the long terr~. However, it has also been ~ound ti~at to be ei~i'ectiYe- ~or C~J .hu3~4~ marine algae, as well as higher developed marlne o-~ s, ~rom the painted surilace o~
ship bottoms, a certain minimum leaching rate o~ tirl o~ about 9 to 16 ug/cm2/day is required. UsuaLly, thi~c higher leaching rate is achieved with a ~ /n 0~ tributyltin compound at about 15%
to 2096 by weight o~ paint.
Obviously, these two ~ui-~T are at odds. Authorities have lel~ ~la~ agreed that ~ig long a~c there is no SAt~ ul~1 substi-tute ~or the anti-~oulant or~anic tin actiYe hl~ , . Iar~er ships, i.e., those above a len~th o~ 25 meters, are stilt permitted to use such to minimize ~ouling. As an indication o the i . Ia-lc~
o~ new solutions to this a"e old problem, the EPA has agreed to cer-tii'y within 90 dayg new ann-~oulant paints meeting the l_~lU;l'elYl~
~ '` release rates.

21 92395 ~:

DISCLOSURE OF THE INVENTION

5 According to an aspect of the present invention a method for retarding fouling of an d~l W~ l surface of a marine structure by marme pests which comprises applying acoatmg of a paint to the surface, the paint containng a biocidally effective amount of 3-iodo-2-propynyl propyl ca~bamate, 4-iodo-3-bytynyl propyl carbamate and mixtures thereof in admixture with a solvent and a binder.
According to amother aspect of the invention a method for retarding fouling of an under~vater surface of a marine structure by marine pests which comprises applying a coating of a paint to the surface, the paint containing a biocidally effective amount of 3-iodo-2-propynyl propyl carbamate in admixture with a solvent amd a binder.
According to yet another aspect of the invention a method for retardirlg fouling of an l..ll.i~l W~ l surface of a marine structure by marine pests which comprises applying a coatmg of a paint to the surface, the paint containing a biocidally effective amoumt of 4-iodo-3-butynyl propyl carbamate in admixture with a solvent amd a binder.
DETAILED ~ESCRIPTION OF THE PREFERRED ES~BODIMENTS
Sn ~ , ~ ~ ~ wlth the present invennon, a biocldal compasl-tlon Is provlded whlch is uselul ror ~.,t~ ~ ~rraces such a~ w~od and other m~tcslals e~po6ed to an aquaac (marlne) c...;r~ nt trom 25 att~ck by ma~le S~st~. Sn the tirst aspect o~ the inventlon, the com-podtlon contains ~l synergi5tic mixture of a) at least on~ 5~ ../I c.. ~- compound havin~ a rOrmula:
t~C ~ C-~CH~)n-O-C-lnl]mR
In whlch m is 1, 2 ~ 3: n 5 1, 2 or 3; and R Ss hydrogen (H); an tu~ed or s~ aSXyl, aryl, aralkyl aSkylaryl, aSkenyl, cycloaSkyl, or ~.,lo~ I or an alkoxy aryl a~l hav~y trom one to 2l~23q~
not more than 2 0 carbon atoms, and m and n may be the same or different, and b) at least one trihydrocarbyl tin ~ 1 having a f ormula:
S F~2 Rl- n_R~

R

10 where Rl, R2 and R3 can each be an alkyl or cycloalkyl having ~rom l to 6 carbon atoms or an aralkyl or alkaryl having from 6 to 12 carbon atoms and R~ is selected from (r~r~r~T~r~2)3Sno~ fluoride, chloride, phosphate, acrylate, methacrylate, naphthenate, hydroxide, octoate, phthalate, 15 sul~ate, maleate, fumarate, laureate, linoleate, abietate, and ethAr- lrh~nAte having a weight ratio of carbamate to trillydLv.iaLlyl tin o~ rrOm about 1:10 to 10:1.
Suitable R substituents for the iodoalkynyl 20 carbamate _ __ ' include alkyls such as methyl, ethyl, proply, n-butyl, t-butyl, pentyl (amyl), hexyl, heptyl, octyl, nonyl, decyl, dodecyl, octadecyl, cycloalkyls such as cyclohexyl, aryls, alkaryls and aralkyls such as phenyl, benzyl, tolyl, cumyl, hAloqonAted alkyls and 25 aryls, such as chlorobutyl and chluLv~ ..yl, and alkoxy aryls such as eth~,Ay~ 1 and the like. Thus, suitable aLl,a~ate: '- are sel ected from the group consisting of 3-iodo-2-propynyl butyl ~arL~ate (IPBC), 3-iodo-2 ~Lv~yllyl hexyl carbamate (IP~C), 3-iodo-2-30 propynyl cyclohexyl carbamate (IPCC), 3-iodo-2-propynyl phenyl v aLLa~ te (IPPhC), 3-iodo-2-propynyl benzyl carbamate (IP Benzyl C), 3-iodo-2 PLV~YIIY1 propyl _~L~a~dte (IPPC), 4-iodo-3-butynyl propyl carbamate tIBPC), 3-iodo-2 ~L~,~y--yl-4-chloro phenyl carbamate 35 (IPClPhC), 3-iodo-2-propynyl-4-chloro butyl carbamate ( IPClBC~ and mixtures thereo~ .

2 ~ 923~5 A preferred group of carbamate fungicides for use with the trihydroCarbyl tin ~ is represented by the formula:
~: C-~CN2~,1-O-C-!15--., 2 ~ 923 95 ~.
g where n is 1 or 2 and R is propyl, butyl, hexyl, cyclohexyl, phenyl or benzyl.
Two lodoaLkynyl carbamate c ~ l-u~ , which haYe surprislng erricacy for controLling rouling of marine structures when used alone, when used in combination or when used in admlxture with trihydro-carbyl ffn ~IA~ are 3-iodo-2-propynyl propyl carbamate (IPPC) and 4-iod~3-butynyl propyl carbamate (IBPC).
Suitable Rl, R2 and R3 ~ ror the trillyd.u~.Ll,~l tin ~omrlln~e are aLkyis such as methyl, ethyl, propyl, butyl, pentyl (amyl) and hexyl, cycloaLkyls such as .1~.01le,~yl; aryls, araLkyls, or allcaryls such as phenyl, benzyl and tolyl. These sub~tituents can aLL
be the same, such as tfibutyl, triphenyl and the lilce or can be dirfer-ent such as die~ lbul~l, dlel~ L~ diamylmethyl, ~Ipl.
eLll~Rlipl-e--~l and the Llke. Suitable lLih~ uC~byl tin ~ ru ~
include Lll~.~.lulle~l tin chloride, tributyl tin chloride, trimethyl tin chloride and triphenyl tin chloride. Pre~erred l~ d~ L~I tin com-pounds are selected rrom the group Or tributyltln ~A r~ consist-ing or bis (tributyltin) oYid~ (TBTO), tributyltin rluoride (TBTF), tributyltin n._.l-~.. rl.~te, tributyltin rhnerh~, tributyltin naphthenate and mixtures thereor.
GeneraLly, the ~ riv j or the present irYentlon are for-mulated as paints lacquers, stains, enamels and the L~ke, hereinarter reierred to genericaLLy as "paint", and wiLL include a liquid vehicle (solvent) ~or dissolving or ~ the actiYe biocidal ingredients and an organic binder. The vehicle may typicaLly contain at least one Or a diluent, an emulsirler and a wetting agent.
Any conventional organic blnder may be utilized In marine anti-rouling paint ill~u~ tlllg the biocidal ~ - ~ ' or the present invention and particularly the ~ .lc anti-foulant mix-ture Or the present invention. Examples Or ~L~ r~Cusl~el binders are polyYinyl chloride resins in a solvent based system, chlorinated rubbers in a solvent based system, acryLic resins and methacrylate resins ln solvent based or aqueous systems, vinyl chloride-vinyl ace-tate copolymer systeme as aqueous ~ or solvent based sys-tems, butadiene ~u~l~ such as ~ ..di_..~ re-lè rubbers, .. _ .. _ . . . . . .. _ . _ _ _ .

a~lu.-ltrile rubbers, and bul~ y~ a.lJlOI ilrile rubbers, drying oils such as linseed oil, alkyd resins, asphalt, epoxy resins, urethane resins, polyester resins, phenolic resins and the like.
The paints commonly may contain inorganic pigments, such as titanium dioxide, rerric oxide, silica, talc, or china clay, organic pig-ments such as carbon black or dyes insoluble in sea water, and may contain materials such as rosin to provide contro~led release oi' the anti-roulant, rosin being to a very slight extent soluble in sea water.
The paints may contain plasticizers, rheology cl~ ic modiliers and other conventionai 11.$., " '~
In still other aspects or the present invention, the composi-tions, par~ l.. ly when ~u.. la~ as paints, also are provided with other ad~uvants ~v..v~lltlu..ally employed in compositions used ror ting materials exposed to an aquatic c:llvl-u-~. .t such as addi-tional ~ungicides, auxiliary solvents, processing additives such as deloamers, rixatives, ~ , UV-stabilizers or stability enhanc-ers, water soluble or water insoluble dyes, color pigments, slccatives, corrosion inhibitors, i ' or a~ t agents such as ...y~.e.l.yl cellulose, polyarcylic acid or puly ~~h~^rylic acid, anti-skinning agents and the like. Additionai rungicides used in the C~ L~-~c~ are pre~erably soluble in the liquid vehicle.
The synergistic biocidal ~nmrcit1nn or the present inveQtion generally comprises rrom about 0.1 to 10 parts by weight, more gener ally rrOm about 0.2 to 5 parts by weight, and most Orten irom about 0.3 to 4 part by weight Or at least one ~-il-~J~ 1 tin ~mrl~n~i, r~ d~ one selected rrOm the group consi5ting Or bis(tributyltin) o~de, tributyltin fluoride, tributyltin rr-t~- ~lalc:, tributyltin phos-phate and tributyltin nqrhthPnotP and mi~tures thereof per part by weight Or the iodoalkynyl carbamate c . i, with the carbamate compound prererably being selected rrOm the group consisting Or 3-iodo-2 ~ uylljl tul~l carbamate, 3-iodo-2-prownyl hexyl carbamate, 3-iodo-2-propynyl ~ yl carbamate, 3-iodo-2-pro-pynyl phenyl rorb~motP, 3-iodo-2-propynyl benzyl carbamate, 3-iodo-2-propynyl propyl carbamate, 4-iodo-3-butynyl propyl 2~ 92395 ...a~e, 3-iodo-2 p-u~yll~l 4 ~I-loro phenyl carbamate, 3-lodo-2 ~ù~y~ l 4 cl-loro butyl carbamate and mixtures thereor.
C~mrncit~nnc o~ the present invention can be provided as a ready-~or-use product in the orm or aqueous solutions and disper-sions, oil solutions and ~ iulls, emulsions, aerosol preparations and the like or as a CU~ . The concentrate can be used as is, for example as an additive ~or paint, or can be diluted prior to use with additionai solvents or ~ L~ g agents.
When the cnmrc~Si~lnc are supplied as a concentrate with the active ir";.èdle-lla dissolved or dispersed in a iiquid vehicle or carrier material, the active biocidal ingredient or mixture of ingredients typi-cally comprises Irom about 0.1% by weight up tû about 80% by weight oi the total composition. Arter ~ t~nn as a paint, the prepara-tion typically wi~l contain rrom about 0.1% by weight up to about 40%
by weight, more general~y rrOm about 1.0% to about 20% by weight, and mo~ct o~ten rrom about 1% tû about 10% by weight of the active ingredient or mixture of active ingredients. A liquid vehicle normally comprises more than about 70% by weight, and more generally above about 90% by weight of the ~ r~ ] ~ when it is rormulated as a paint. In some ~ ateS, however, the liquid vehicle can consti-tute as little ac 5% by weight of the ~ "p~
The liquid vehicle is not a criticai aspect of the present inven-tion and any liquid which does not interfere with the biocidal activi-tie_ oi' the active In~ ' and which is ~omr~tihl~ with the dis-ciosed ,,~ c potentialiy can be used in the present invention.
Suitâble materiais ror the iiquid vehicle include water and organic solvents including aliphatic l~yd~ ..bu-~, aromatic l-ydl~ lbul~, such as xylene, toluene, mixtures or aliphatic and aromatic hydrocar-bons having boiling points between 100 and 320C, prererably between 150 and 230C; high aromatic petroleum distillates, e.g., solvent naptha, distilled tar oii and mixtures thereof; alcoho-s such as butanol, octanol and glycois vegetable and mineral oils; ketones such as acetone petroleum ~ractions such as mineral spirits and Icerwene, chlorinated ll~d~ a.lJo-b, glycol esters, glycol ester ethers, and the like. The liquid vehicle may contain at least one polar solvent, such .. _ .. _ ., . . . , . . _ . _ _ _ _ . _ _ _ as water, in admlxture with an oiiy or oil-like low-volatility organic solvent, such a_ the mlxture or aromatic and aliphatic solvents ~ound in white spifits, also commonly called mineral spirits.
The liquid vehicle also may commonly include an emulsifier, a wetting agent, a dispersing agent or other surrace active agent.
Examples o- suitable ~ ~,JIciri~ ~ are the nu--y~ è~lol ~tllylel~e oxide ethers, and pOlyu~Lye~ lel~è sorbitd esters or ~ulyu~Lyetllylelle sorbitan esters Or ratty acids. For example. a userui formulation may contain the mixture or the active biocidal ~nnctituPntc dissolved in an ori~anic solvent such as mineral spirits which iQ turn is emulsiried with the aid o~ a suitable emulsirier in water as the primary liquid vehicle.
An aerosol preparation according to the invention is obtained in the usual manner by illcùl~v~alll~ the active ingredients dissolved or suspended in a suitable solvent, in a volatile liquid suitable ror use as a propellant, ror example the mixture or chlorine and ~luorine defivatives o~ methane and ethane commerciaiiy available under the trademark "Freon", or r ~ air.
The balance o~ the; I, ' may include additional ingre-dients known to be use~ul in preservatives and coaffngs ror aquatic applications and related products. Such ingredients include ~ixatives such as ~;a.bu~yl~rthylcellulose~ polyvinyl alcohol, a pararrin and the like, c~ ~IvèllL~, such as ~ yl~ 1 acetate and ~ .I-u~y~ l ace-tate and ~ _IJ- 1~ ~ such as benzoic acid esters and phthiates, e.g., dibutyl phthalate, dioctyl phthaiate and didodecyl phthalate. Option-ally dyes, color pigments, corrosion inhibitors, chemicai st~hil~7Prs or siccativeC (dryers) such as cobalt octate and cobalt n~rhthPn ItP also may be included depending on speciric Irrl~at~nnc Such additionai Ill,sl~i;el.t~ are not essential to the practice Or the present invention but are included in particular rormulations to optimize overali e~(~_Ll~e~ea~ and ease d arp~ t~nn The specLric examples o~ suitable ~J--~LItL_..L~ for specii'~c preparations as enumer-ated above are not meant to be lim~ting and a wlde variety o~ other possible ill!LLeliellL~ wiLi be l~c~ ed by those skiLied in the art.
Simiiarly, the quantity o( such additional ingredients in any . , .... .. . . _ .. . .. . . .. _ _ _ _ _ _ . _ _ .

2~ 92395 formulation is not critical. They generally can be used in an amount conventionally employed ~or products designed to be used in applica-tions lar protecting materials exposed to an aquatic environment.
Normally, the totally ~ormulated c~nr~ , may contain from about 0.1% to 95% by weight, and more usually from about 1% to 50% by weight o~ these additional i~ on a totai solids basis.
Biocidal compositions ol the present invention can be applied by any of the t~-~hniqll~c known in the art including brushing, spray-ing, roll coating, dipping and the like. Generally, to obtain ef~ective t, it should be surficient to apply the ~ r~ in an amount to provide between about 20 to 180 grams o~ the active ingre-dient or mixture o~ active illt~ per square meter o~ surlace area to be treated (about 0.0040 to 0.037 pound per square ~oot), with an amount o~ about 80 to 120 g/m2 (about 0.016 to 0.025 lb/~t2) being more typical. or course, higher rates or ~rr'i~lti~n can be used ir desired.
cnm~nC;tinnC Or the present invention can be prepared simply by mixing the various ~ tc at a ~ e-~ lu--~ at which they are not adversely arfected, e.g., at a temperature of from about -5C to 80C, preferably at a ~Lupe.~ ~u-e Or ~rom about 10C to 45C and at a pressure Or 450 mmHg to 900 r~mHg, preferably at a~out 650 mmHg to 850 mmHg. Preparation conditions are not critical. Equipment and methods Q~ lu..ally employed in the m~nll- ~ule o~ paint and similar , ' can be .d~ u~l~ employed.
In ,..~ ' ~ testC over a period o~ 7.5 weeks during the sum-mer, which is a high growing season for marine organisms, test panels were coatec with a representative paint used as a base for preparing antl-fouling paintC and were placed in seawater. Ihe base paint was mixed with the individual rnm[~lln~c listed in the table below up to a concentration o~ 10 wt. 96. The individual test results are listed in the lollowint table:

Use ComDound Level 4 Weeks 6 Weeks 7.5 Weeks TBTO 10% clean clean m. growth TBTF 10% clean clean m. growth IPBC 10% clean sl. rowth h. rowth IPCC 10% clean sl. rowth h.-rowth IPPhC 10% clean sl. rowth h. rowth IP Benzyl C 10% clean sl. rowth h. rowth TBTO/IPBC 5%+5% clean clean clean TBTO/IPBC 3.5%+6.5% clean clean clean IBTO/IPBC 3.5%+3.5% clean clean clean TBTO/IPBC 2%+8% clean m. growth sl. growth TBTO/IPBC 8%+2% clean clean m. growth TBTO/IPBC 6.5%+3.596 clean clean clean Note: m = moderate, sl = slight~ h = heavy The table shows slight to heaYy growth ~or IPBC and its deriva-tives, as well as moderate to slight growth ~or the tributyltin deriva-tives used at a concentration ot 10 wt. % in the paint composition.
A~ter 7.5 weeks, however, in aLi instances the individual biocides showed signs o( failure at use levels o~ 10 wt. %.
Su.t-6il"~1y, the synergistic . ' o~ the present inven-tion showed a superior elficacy when used in the same total amount.
Suitable points can be made up using a ratio ot 1 wt. % TBTO and 10 wt. % IPBC up to 10 wt. % TBTO and 1 wt. % IPBC. Primarily, when IPBC and TBTO were used in a ratio o( 1:4 to 4:1 the mixture showed excellent performance with an optimum close to a ratio or 1:1 ~y weight.
With a second test series the ratio Or 1:4 to 4:1 was evaluated in ~.~ln~ total amount o~ the sum of both biocides. Even at a totai Or ~% or active ingredient pre~erably in the ratio or 1:1 added to a standard coating (paint) ~or ship bottoms, the ~.5 week test period contlnued to indicate superior activity, in ~ ~-- to TBTO at a higher level. These ~. L5 clearly show that the combination o~
IPBC and TBTO is more efrective than IPBC or TBTO applied on their own as anti-~ouiing biocides, indicating a synergistic ef~ect.
Prererably, the two ~ ..~ are premixed berore use to ~orm a concentrate in the ratio or 1:4 to 4:1 in a concentration up to a totai or 80% dissolved in suitable auxiiiary solvents like Xylol or the _ _ _ _ _ _ _ _ _ , _ _ . _ _, _ . . .

like to provide easy and ~ùm~ eùu~ dl~llibu~lu~ in the paint, which is intended to perform as an anti-fouling coating.
The (ollowlng examples are illustrative ot cù-npo~ltlu--a accord-ing to the present invention and are not intended to be limiting.
ExamDle 1:
3-iodo-2-propynyl butyl carbamate 5%
tributyltin oxide s%
auxiliary solvents 3.3%
vlnyl acrylic paint 86.7%
Example 2 3-iodo-2-propynyl butyl carbamate 4%
bis (tributyltin) oxide 5%
auxiliary solvent 4%
vinyl acrylic copolymer paint 87%
ExamDle 3:
3--iodo--2--pro nyl butyl C<~-IJdl-ld~ 3.5%
bis (tributyl$ oxide 3.5%
auxiliary solvent 3,0%
vinyl acrylic paint 90.0%
Exam~le 4:
3-iodo-2-propynyl butyl carbamate 6%
bis (tributyltin) oxide 3.5%
auxiliary solvent 3.3%
vinyl acrylic ~u~l,~ paint 87.2%
ExamDle 5:
3-iodo-2-propynyl butyl carbamate 4%
bis (tributyltin~ oxide 4%
auxiliary solvent 4%
oil based aLkyd resin paint 88.0%
ExamDle 6:
3-iodo-2-propynyl butyl ~ d---ale 5.0%
bis (tributyltin) oxide 5.0%
auxiliary solvent 4.0%
pigments 10.0%
epoxy based paint 76.0%

.

ExamDIe 7:
3-iodo-2-propynyI buty1 carbamate 4.0%
bis (tributyltin) oxide 6.0%
auxiliary solvent 3.0%
pigments 10.0%
chlofinated rubber based paint 77.0%
ExamPle 8:
3-iodo-2-propynyl butyl carbamate 5.0%
bis (tributyltin) oxide 5.0%
auxiliary solvents 5.0%
acrylic based paint 85.0%
Example 9:
3-iodo-2 ~ yI butyl carbamate 6.0%
tributyltin oxide 4.0%
auxiliary solvent 6.0%
urethane based paint 84.0%
While certain specific . ,l~llm ..~ of the invention have been described with particularity herein, it wili be .~ i that various m~i~ 3tinn.c thereo~ will occur to those skilled in the art and it is to be ~ ~i that such m~~ t;l-ne and variations are to be include~i within the purview of this ~rr~ ti~n and the spirit and scope o~ the appendeli claims.

Claims (3)

1. A method for retarding fouling of an underwater surface of a marine structure by marine pests which comprises applying a coating of a paint to said surface, said paint containing a biocidally effective amount of 3-iodo-2-propynyl propyl carbamate, 4-iodo-3-butynyl propyl carbamate and mixtures thereof in admixture with a solvent and a binder.

2. A method for retarding fouling of an underwater surface of a marine structure by marine pests which comprises applying a coating of a paint to said surface, said paint containing a biocidally effective amount of 3-iodo-2-propynyl propyl carbamate in admixture with a solvent and a binder.

3. A method for retarding fouling of an underwater surface of a marine structure by marine pests which comprises applying a coating of a paint to said surface, said paint containing a biocidally effective amount of 4-iodo-3-butynyl propyl carbamate in admixture with a solvent and a binder.