Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/04—Homopolymers or copolymers of esters
  • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D157/00—Coating compositions based on unspecified polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/16—Antifouling paints; Underwater paints
  • C09D5/1656—Antifouling paints; Underwater paints characterised by the film-forming substance
  • C09D5/1662—Synthetic film-forming substance
  • C09D5/1668—Vinyl-type polymers

Definitions

• This invention relates to marine antifouling paints which erode at a predetermined rate, and more particularly to a polymeric binder for an antifouling paint where the polymer includes moieties which hydrolyze at a predetermine rate in the presence of sea water.
• the organotin acrylate copolymer serves as the film-forming component (binder).
• the hydrolysis of the organotin polymer releases bis-tributyltin oxide, an effective antifouling toxicant.
• organotin copolymer antifouling paints function is described in Journal of Coatings Technology, Vol. 53, Number 678, pages 46-52. Such paints, however, are relatively expensive and possess undesirable irritative properties due to the necessary presence of the hydrolyzable tributyltin moiety.
• Spent antifouling systems of this type do not provide a suitable base for repainting since they possess poor mechanical properties due to the voids in the film which result in poor adhesion of the new paint film.
• Prior art attempts to incorporate toxicants into water soluble polymers and to use these as antifouling paints have also failed to produce the desired results.
• Such paints swell in seawater and cannot be expected to provide good mechanical properties and uniform control of fouling since the whole paint film is weakened on prolonged water immersion.
• Simple acrylate ester copolymers are proposed as vehicles for paints which are gradually planed away by moving seawater in U.S. Patent No. 4,407,997, published May 26, 1982.
• a major proportion of the pigment used must be a water-sensitive metalliferous pigment.
• such coatings must contain from 35-50% by volume of pigment with the higher levels being preferred. Highly insoluble pigments retard the dissolution of the paint film and must be kept below certain specified levels. It is thus evident that the pigment content is being dictated by the required dissolution rate.
• a paint which is produced from a binder polymer resulting from the copolymerization of one or more copolymerizable ethylenically unsaturated monomers and a monomer having a functional group which produces a polymer which is hydrolyzable in seawater.
• an antifouling paint which includes a toxicant, a pigment and a polymer binder.
• the polymeric binder is film-forming, water insoluble, seawater erodible and is represented in one embodiment by the formula
• X is H or CH 3 ;
• R is a substantially non-bioactive, alkyl, aryl or arylalkyl moiety; and recurring groups B, where B is the residue of an ethylenically unsaturated monomer.
• the polymer has a hydrolysis rate of at least 5X10 -4 milliequivalents per hour.
• the resultant paint has an erosion rate of at least 2 microns per month.
• R can be selected from the group consisting of:
• Z is NO 2 , halogen or CN; b) -(CH 2 ) n Y wherein n is an integer from 1 to 4; and
• Y is selected from the group consisting of
• R' is C 1 to C 4 primary, secondary or tertiary alkyl
• R" is H or R' ;
• R' ' ' is alkyl or an aryl; c) can be -SIR''' or -Si(OR''') 3 ; d) R can be a halo alkyl group having at least one trihalomethyl group where the halogen is Br, F, Cl, and the alkyl has at least two carbons, e.g. trifluoroethyl acrylate; e) a quaternized amino alkyl represented by the formula
• R' , R" and R' ' ' are the same or different C 1 to C 18 alkyls; and wherein n is 1 or 2;
• R" is a phenyl group or a C 1 to C 4 primary, secondary or tertiary alkyl.
• X is halogen, CN, or NO 2 .
• R is C 1 to C 8 primary, secondary or tertiary alkyl.
• the polymer of the present invention can serve entirely as a toxicant delivery system, and is not dependent upon the hydrolysis of an organotin or bioactive component containing polymer. Thus, any effective antifoulant can be incorporated into the paint.
• the paint is produced from a binder polymer resulting from the copolymerization of (1) at least one acrylic or methacrylic ester having a functional group which produces a polymer which is hydrolyzable in seawater and (2) one more copolymerizable ethylenically unsaturated monomer.
• ester it is possible to modify the ester to produce enhanced hydrolytic sensitivity of the polymer. This can be accomplished by providing a functional group which assists or enhances the attack by hydroxyl ions or by weakening the ester bond.
• Z is NO 2 , halogen or CN.
• An example is p-nitrophenyl acrylate.
• R can also be represented by the formula: -(CH 2 ) n Y wherein n is an integer from 1 to 4; and Y is selected from the group consisting of
• R' is C 1 and C 4 primary, secondary or tertiary alkyl
• R' ' is H or R' ;
• R' ' ' is alkyl or an aryl. It should be understood that references to alkyls, aryls and the like is intended to include substituted alkyls aryls, etc.
• R can also be -SiR''' 3 or -Si(OR''') 3 , where R' ' ' is an alkyl or an aryl, as for example triphenylsilyl acrylate.
• R can also be a quaternized aminoalkyl represented by the formula
• Y is Br, Cl or I
• R' , R' ' and R' ' ' are the same of different C 1 to C 18 alkyls.
• R is a haloalkyl having at least one trihalomethyl group, where the halogen is Br, F or Cl and the alkyl has at least two carbons, as for example trifluoroethyl acrylate.
• Typical of the haloalkyl alcohols are the compounds described in DuPont Zonyl R Flouoro- surfactants Product Information Bulletin 8/82.
• R can also be a tertiary alkyl group having four or five carbons. It should be noted that the term alkyl as employed herein is intended to be understood to the generic term which is inclusive, for example, of linear, branched, cyclo and substituted alkyls.
• R can also be -(CH 2 ) n , where n is 1 or 2 and R"" is a phenyl group or a C 1 to C 4 primary, secondary or tertiary alkyl, as for example, 2-oxopropyl methacrylate or 4-phenyl- 3-oxobutyl acrylate.
• R is a C 1 to C 8 primary, secondary or tertiary alkyl and X is halogen, CN or NO 2 , as for example, 2-ethylhexyl chloroacrylate.
• the polymer can be synthesized by copolymerization of a particular monomer with a comonomer.
• the polymer can be produced by adduct ion to a preformed acrylic or methacrylic acid polymer.
• the resultant polymer will include a recurring group represented by the structure
• the paint formulation includes the polymeric binder, a solvent, a toxicant and can include a water sensitive pigment component, which can be a toxicant, inert pigments and fillers along with a retarder.
• a water sensitive pigment component which can be a toxicant, inert pigments and fillers along with a retarder.
• Antifouling toxicants include tributyltin fluoride, triphenyltin hydroxide, triphenyltin fluoride, tributyltin oxide, triphenyltin chloride, Cu 2 O, ZnO, dithiocarbamate derivatives and cuprous thiocyanate.
• the paint formulation employs sufficient solvent to enable the system to be applied to the surface to be protected.
• the pigment volume concentration (PVC) should be in the 10 to 50 range, and preferably is from about 30 to 45.
• the upper limit for the hydrolysis of the polymer used in the paint is not of critical importance because even with an excessively rapidly hydrolyzing polymer, a desired erosion rate can be achieved by proper selection of the ratio of functional group to polymer or copolymer or the use of a retarder as disclosed in U.S. Patents 4,021,392; 4,260,535; and British Patent 1,589,246, the disclosures of which are incporated herein by reference.
• the erosion rate of the paint is dependent upon the total contributions of the functional group, the co-monomer and other components, such as toxicant(s), pigment(s), retarder(s), fillers, inerts or other non-volatile components of the paint.
• the functional group of the present invention can work in conjunction with known erosion rate controls or in place of known means to regulate the erosion rate.
• the amount of the hydrolyzable acrylate or methacrylate to non-hydrolyzing, ethylenically-unsaturated comonomer, on a mole basis, in 100 parts of the copolymer is from 10 to 90 parts.
• the acrylic or methacrylic ester of an amino or quaternized amino alkyl alcohol from 10 to 100 parts; in the case of an acrylic or methacrylic ester of haloalkyl alcohols, from 10 to 80 parts; in the case of nitrophenol or nitrobenzyl alcohol ester and 10 to 80 parts in the case of trialkyl, triaryl or trialkoxy silanol esters 10-80 parts.
• ethylenically unsaturated comonomers are well known in the film forming art and are identified for example, in British 2,087,415A, page 1, lines 56 to 59, and U.S. 4,021,392, column 4, lines 33 to 41, the disclosures of which are incorporated by reference.
• the superior control of the erosion rate relies on chemically tailoring the polymer so that it is selectively weakened at certain points pendant to the polymer chain at the paint/water interface. These weak links are slowly attacked by seawater allowing the polymer to gradually become seawater soluble or seawater swellable. This weakens the hydrolyzed surface polymer film to such an extent that moving sea-water is able to wash off this layer and thus expose a fresh surface.
• the paint is relatively impermeable to seawater until hydrolysis of the outer microlayer takes place. The hydrolyzed microlayer is then sequentially removed by the water "friction".
• a portion of the monomeric units are provided with functional groups which provide a site of weakness, that is, sites which tend to hydrolyze in the presence of seawater.
• the ratio of functionalized monomers to non-functionalized monomers is controlled to provide control of the erosion rate.
• the system of the instant invention is controlled by the levels and ratio of functional and inert monomers used to prepare the polder.
• DMAEMA dimethylaminoethyl methacrylate
• Amsco Solvents - can use xylene as replacement.
• Representative Polymer Compositions varied mole % hydrolysis-inducing monomer, balance methyl methacrylate and/or butyl methacrylate.
• TFEA trifluoroethyl acrylate
• DMAEMA dimethylaminoethyl methacrylate
• TAAEMA t-butylaminoethyl methacrylate
• the trimethylammonium hydrochloride was removed by vacuum filtration and the acetone was removed on a rotary evaporator.
• the solid product was dissolved in 150ml of warm methanol from which it crystallized on cooling.
• Paints containing low and high levels of cuprous oxide, an accepted antifoulant and based on representative hydrolyzable polymers exhibiting suitable hydrolysis rates were prepared and tested for fouling resistance.
• the test paint compositions and method of preparation are described below.
• Test Paint A Preparation The fumed silica is dispersed in xylene with a moderate speed dispersator (Cowles-type). The methanol is added while stirring, followed slowly by half of the polymer solution. All the pigments are then added with moderate agitation and the resultant paste is ground in a water-cooled steel shot mill. The mill is washed with a mixture of the ketone and the remainder of the polymer solution and the washings are added into the paste. The entire paint is mixed and passed through the mill once more. The paint should be at a fineness of grind of 4-6 (Hegman gauge) . The paint may be adjusted for a final viscosity of 1,000 to 1,500 cps with solvent.
• Test Paint B Preparation
• the fumed silica is dispersed in xylene with a moderate speed dispersator (Cowles-type).
• One half of the polymer solution and one half of the paint stabilizer are slowly added, followed by the dispersing aid and the cuprous oxide.
• the resultant paste is ground in a water-cooled shot mill.
• the mill is washed with a mixture of the ketone and the remainder of the polymer solution and the stabilizer into the paste.
• the well-mixed paint is passed through the shot mill once more and checked for. a desired fineness of grind (Hegman gauge) of 4-6.
• the paint is adjusted for a final viscosity of 1,000 to 1,500 cps (Brookfield) with solvent.
• the toxicant delivery system of the invention is capable of delivering toxicant at a substantially constant rate over the required time period.
• the delivery rate is independent of the solubility characteristics of the toxicant, and consequently the minimum marine fouling prevention quantity of toxicant can be employed in the system.
• the avoidance of the requirement for excess toxicant can produce a significant cost savings, as compared to a system in which excess toxicant is used because of a non-uniform toxicant delivery rate and/or a need to optimize the hydrolysis rate of the system.
• the term polymer hydrolysis rate refers to rate of production of carboxylic ions by 5 g of powdered polymer film. The availability of carboxylic ions is dependent upon the concentration of the functional group in the polymer. The toxicant release rate can thus be customized, based on the polymer dissolution rate.
• the polymer hydrolysis rate is determined in accordance with the following procedure.
• the utility and novelty of the paint systems lies in the recognition that the bulk of the paint is water insoluble and only the surface of the film, which is in contact with seawater hydrolyzes and thereby is slowly converted to a water-soluble or water-swellable form. This layer can be eroded away by moving seawater, releasing the physically bound toxicant to prevent fouling and exposing a fresh paint surface. With this mechanism, the hydrolysis of the polymer and the rate at which the hydrolysis proceeds governs the ability of the paint film to erode and control fouling. This rate of hydrolysis can be measured under conditions which simulate the action of moving seawater.
• Paint was applied in the center of the panels to a dry film thickness of approximately 100 microns with a draw down blade applicator. The outer edges were uncoated and provided a measure of the total fouling challenge.
• Panel Exposure The panels were suspended from rafts in Biscayne Bay, Florida. The submerged racks hold 8 panels, 1 foot below the surface - with 2 inches of space between panels.
• test paint A formulations incorporating relatively low levels of the functional monomers in the binder polymer See Tables 2 and 3.
• the static panel results on the antifouling paints prepared with relatively low levels of tin free functional acrylic polymers show varying degrees of effectiveness in providing control of marine fouling following three months' exposure.
• paint no. 2-5 is by far the most effective with complete control of barnacles and algae. Paint systems based on DMAEMA (Paint No. 2-1), tBAEMA (No. 2-8) and TFEA (No. 2-9) are effective against barnacles but poor in providing control of algae, suggesting that the aproper release rate of copper has not yet been achieved in these systems. Paint system No. 2-4 is somewhat effective against barnacles and algae at the three month exposure time.
• Tables 3 and 4 show the results of testing paints with higher levels of the functional monomers in the binder polymer.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paints Or Removers (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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Cited By (27)

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Citations (8)

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• 1984
  • 1984-01-17 MX MX200055A patent/MX159906A/es unknown
  • 1984-01-17 DE DE8484900793T patent/DE3478309D1/de not_active Expired
  • 1984-01-17 WO PCT/US1984/000068 patent/WO1984002915A1/en not_active Ceased
  • 1984-01-17 JP JP59500888A patent/JPS60500452A/ja active Granted
  • 1984-01-17 EP EP84900793A patent/EP0131626B1/en not_active Expired
  • 1984-01-17 AU AU24971/84A patent/AU573204B2/en not_active Expired
  • 1984-01-17 NZ NZ206852A patent/NZ206852A/en unknown
  • 1984-09-14 DK DK198404406A patent/DK172886B1/da not_active IP Right Cessation
• 1990
  • 1990-09-20 CA CA000615870A patent/CA1295893C/en not_active Expired - Lifetime

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