[0001] This application claims priority to our co-pending U.S. Provisional Application having serial number 61/694,432, filed on August 29, 2012.

Field of The Invention

[0002] The field of the invention is compositions and methods of removing antifouling paint from various substrates, and especially marine antifouling paint from marine vessels.

Background

[0003] Traditionally marine antifouling coatings are formulated using synthetic resins as well as natural rosins to which an active ingredients package is added. Most typically, the active agent is based on copper and includes metallic copper, inorganic copper (provided as oxides) and organic copper, which may be present in various levels and combinations. The slow release of the copper is controlled by the nature of the resin-rosin part of the formulation. More recently, silicone resins were formulated in a large variety of antifouling paints to provide for increased efficacy, reduction of friction with water and self cleaning properties.

[0004] Antifouling coatings are generally only effective as long as the copper content released from the surface of the paint is sufficiently high to deter growth of fouling organisms. The life expectancy of such coatings is in most cases between two and five years, after which the coating needs to be replaced. Due to environmental considerations, sanding is prohibited to a large extent. Moreover, sanding or blasting removal will in at least some circumstances be detrimental to the substrate (e.g., fiberglass, gelcoat, aluminum, etc.).

[0005] Others have attempted to provide certain formulations for removing antifouling paint (e.g., Peel Away® Marine Safety Strip (technical data available at

http://www.dumondchemicals.com/pdf/TDS/PA%20Marine%20Safe ty%20Strip%20TDS.pdf, Aqua-Strip®). Unfortunately, such products generally require a large investment of time for application, processing, removal and clean up, require cloth or other materials for application, and provide inconsistent results. In addition, advanced antifouling coating with increased efficacy and smoothness have proven to be a challenge to removal as most known removal agents typically fail to remain in contact for a sufficiently long time to facilitate complete paint removal in a single pass. Consequently, repeated application is often required, which is time consuming and cost ineffective.

[0006] All publications identified herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0007] Therefore, even though numerous methods and compositions are known in the art to remove antifouling paint from a substrate, all of almost all of them suffer from one or more disadvantages. Thus, there is still a need to provide an improved antifouling paint remover that will avidly cling to antifouling coated areas, and effectively remove or assist in removing all or most of the antifouling paint, preferably in one application, without damaging the substrate (e.g., gel coat, fiberglass, aluminum, steel, concrete, etc.).

Summary of the Invention

[0008] The present invention is directed to various compositions and methods for an antifouling paint remover, and especially for a marine antifouling paint remover, that is able to cling with very little or no sagging to a large variety of antifouling marine paints (which may be based on silicone, epoxy, alkyd, thermoplastic polyamide etc.) to thereby lift or remove the paint without causing damage to its substrate.

[0009] In especially preferred aspects of the inventive subject matter, contemplated antifouling paint removers will include two functionally distinct components, a paint solvent and a gelling component, wherein the antifouling paint remover is formulated to allow both brush and/or spray application. Where desirable, the antifouling paint remover can also include at least one of a filler, an emulsifier, an evaporation retarder, a stabilizer, and a chelating agent to impart one or more desirable characteristics for commercial use (e.g., minimized moisture loss, extended storage life, reduced separation of ingredients). [0010] In another aspect of the inventive subject matter, the inventors contemplate an antifouling paint remover composition comprising a solvent component and an in situ gelling component. The solvent component will most preferably comprise a solvent that is suitable to penetrate, and at least partially solubilize, a polymer of antifouling paint (e.g., marine antifouling paint). The gelling component will most preferably be an in-situ gelling component formulated to undergo a sol-gel reaction that is catalyzed by residual copper in antifouling paint (e.g., on a marine hull, yacht, or boat) to form a mesoporous film that clings thereto. Thus, contemplated antifouling paint removers can advantageously be applied to, cling to, react with and lift antifouling paint on a top, side, bottom or any other portion of a substrate with very little or no sagging or dripping, and without causing damage to the substrate. As used herein, the term "no sag" means that at least 90% of a composition, when applied to a 10 cm ² vertical substrate (coated with antifouling paint) at a thickness of 1mm and at room temperature, will be retained on that surface without dripping off for at least 10 minutes. Substrates compatible with compositions and methods of the inventive subject matter can include, among other things, a gel coat, a fiberglass, aluminum, steel, concrete, or any other substrate to which antifouling paint may be applied to prevent the growth of organisms.

[0011] It is most preferred that the antifouling paint remover composition includes a solvent or solvent blend component that includes at least one of a benzyl alcohol and a tert-butyl acetate (TBAc). While not limiting to the inventive subject matter, it is further preferred that the solvent component is present in the composition in an amount between 5-75% (w/w), more preferably between 10-60 % (w/w), and most preferably between 25-50% (w/w).

[0012] Especially preferred in situ gelling components can comprise at least one of an inorganic and an organic silicate, and be present in the composition in an amount of between 1-50% (w/w), and more preferably between 5-25% (w/w). Such gelling components could advantageously form a mesoporous gel on the copper containing antifouling paint to thereby prevent or substantially prevent sagging or dripping of the composition when applied to the antifouling paint. While not wishing to be bound by any particular theory, it is contemplated that the residual copper in the antifouling paint to be removed could catalyze formation of the mesoporous gel, which will cause the antifouling paint remover to cling to the antifouling paint from its substrate, thereby allowing the solvent component to lift the antifouling paint from its substrate. [0013] For example, a preferred composition could include a solvent component and an in situ gelling component, wherein the solvent component comprises a solvent blend of benzyl alcohol and tert-butyl acetate, and is present in the composition in an amount between 25-50% (w/w), and wherein the gelling component comprises a silicate, is present in the composition in an amount between 5-20% (w/w), and forms a mesoporous gel when applied on antifouling paint including copper. The remaining volume of the composition can comprise fillers, emulsifiers, evaporation retardants, stabilizers, chelating agents, water, or any other suitable components.

[0014] Therefore, and viewed from a different perspective, the inventors also contemplate a method of preparing an antifouling paint remover composition that includes the step of including into an antifouling paint remover composition an in situ gelling component. In especially preferred embodiments, the antifouling paint remover composition will comprise a solvent that is suitable to penetrate and at least partially solubilize a polymer of an antifouling paint. In addition, the in situ gelling component will be formulated such as to form a gel upon application of the antifouling paint remover composition on the antifouling paint on a substrate. Most preferably, the antifouling paint remover composition will comprise benzyl alcohol and optionally tert-butyl acetate in an amount of between 5-75% (w/w), more preferably between 10- 60 % (w/w), and most preferably between 25-50% (w/w) in the composition. In addition, preferred in situ gelling components will comprise at least one of an inorganic and an organic silicate in an amount of between 1-50% (w/w), and more preferably between 5-25% (w/w) in the composition.

[0015] One should appreciate that a composition prepared in accordance with a method of the inventive subject matter can advantageously be used to remove antifouling paint from a substrate by clinging to and reacting with the antifouling paint.

[0016] Therefore, in another aspect of the inventive subject matter, the inventor contemplates a method of removing antifouling paint from a substrate that includes a step of applying an antifouling paint remover onto an antifouling paint, and a step of removing the gelled antifouling paint remover and at least part of the antifouling paint. The step of applying the antifouling paint remover can comprise spraying or brushing the antifouling paint remover onto the antifouling paint. For example, a user can apply the remover using an airless sprayer or high volume, low pressure (HVLP) sprayer having a suitable nozzle tip size (e.g., .01 1-.021, .021 -.031, .031 -.041) and chemical resistant fittings.

[0017] In such methods, it is generally preferred that the antifouling paint to be removed will comprise a silicon base, and include a component that catalyzes the step of in situ forming a gel. Most preferably, the step of in situ forming a gel is catalyzed by a copper component of the antifouling paint that reacts with a gelling component of the antifouling paint remover.

[0018] Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention.

Detailed Description

[0019] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

[0020J The inventor has now discovered that various antifouling paint remover compositions can be prepared that will provide not only superior paint removal ability, but also allow the remover to form a film that avidly clings to various types of antifouling paint, and lifts the antifouling paint from various substrates, and especially those including gel coats, fiberglass, aluminum, steel, and concrete, etc. The resulting film can have a viscosity sufficient to allow the antifouling paint remover to cling to antifouling paint on substrates that are upward facing, side facing, downward facing, or anywhere in between, and for a sufficient amount of time to react with and lift the antifouling paint from the substrate.

[0021] In especially preferred aspects of the inventive subject matter, the film will be formed in situ and be mesoporous having a typical pore diameter between 2 and 50 nanometers, inclusive. It is generally preferred that the process that generates the mesoporous film is accelerated by residual copper in the antifouling paint to which it is applied such that the gel rate of the composition exceeds its drip rate, even on vertical or overhead surfaces. While it is in most instances preferred that the resulting film be mesoporous, it should also be appreciated that the resulting film can have any suitable porosity or porosities. Thus, the film can comprise pores having diameters between 0.1 and 1,000 nanometers, more typically between 1 and 250 nanometers. Viewed from a different perspective, the resulting film can be microporous, mesoporous or macroporous.

[0022] In one exemplary aspect of the inventive subject matter, the antifouling paint remover is a liquid formulated from (I) a solvent or solvent blend that is effective to penetrate, solubilize, and swell the various polymers in the resin/rosin or silicone film of the paint, and (II) a (preferably water miscible) silicate gelling component in an amount effective to undergo an in situ gelling (i.e., sol-gel process) that is catalyzed by residual copper in the antifouling paint to thereby form a mesoporous film (typically with a pore size of between 2 and 50nm inclusive). Upon application of the remover composition, a sol-gel process can occur between monomers of the composition to generate a film that provides with an excellent clinging ability to all antifouling coatings, especially to silicone containing coatings, surpassing all of the commercially available antifouling paint removers tested by the inventor. As described above, the sol-gel process can be catalyzed by the residual copper in the antifouling paint.

[0023] In still further contemplated aspects, it should be noted that components making up a composition of the inventive subject matter can vary considerably. For example, a person having ordinary skill in the art should appreciate that suitable solvent components can include one or more of a polar protic solvent (e.g., formic acid, «-Butanol, isopropanol, «-Propanol, ethanol, methanol, acetic acid, nitromethane, water), a polar aprotic solvent (e.g., dichloromethane, tetrahydrofuran, ethyl acetate, acetone, dimenthylformamide, acetonitrile, dimethyl sulfoxide, propylene carbonate), or a non-polar solvent (e.g., pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, 1,4-Dioxane, chloroform, diethyl ether). In some preferred embodiments of the inventive subject matter, the solvent component can comprise one or more paint solvents including for example, benzyl alcohol, tert-butyl acetate (TBAc), methylene chloride, amyl acetate, acetone, glycol ethers, MEK, or any combination thereof. In most preferred

embodiments, the solvent or solvent blend will advantageously comprise benzyl alcohol or other versatile, slow-evaporating, non-flammable, non-combustible and readily biodegradable paint solvent treated favorably under certain VOC regulations.

[0024] In especially preferred compositions, the solvent component will comprise a blend of two or more co-solvents that are partially or completely miscible with one another. Additionally, preferred co-solvents will be a solvent suitable for use in thinners, enamels, lacquers, etc., and be non-toxic or environmentally safe. Thus, and viewed from another perspective, the solvent component could comprise a polar solvent and a non-polar solvent, a polar aprotic solvent and a polar protic solvent, two or more polar aprotic solvents, two or more polar protic solvents, two or more non-polar solvents, or any combinations or variations thereof. For example, where the solvent is a solvent blend comprising benzyl alcohol, co-solvents can preferably include tert- butyl acetate, which is miscible with the benzyl alcohol, is suitable for use in thinners, enamels and lacquers, and has achieved EPA volatile organic compound (VOC) exempt status. It should be appreciated that the PHOSITA will be readily able to determine the best choice of solvent or solvent blend based on the particular antifouling paint. For example, among other solvents that may be miscible with benzyl alcohol and suitable co-solvents are methoxyethanol, acetic acid, methanol, pyridine, and propanol. However, it is typically preferred that the solvent/solvent blend includes benzyl alcohol/benzyl alcohol and TBAc. While not limiting to the inventive subject matter, it is generally preferred that the ratio between benzyl alcohol and TBAc is between 1 : 10 and 10: 1, more preferably between 1 :4 and 4: 1, even more preferably between 1:2 and 4: 1, and most preferably between 1 : 1 and 3: 1. However, all suitable ratios of all suitable co- solvents are contemplated. Moreover, it should be appreciated that while the paint remover may not include a non-organic component, generally preferred paint removers will be water-based, and in most cases include the solvent or solvent mixture in an amount of 10-60% by weight.

[0025] With respect to the in situ gelling component, the gelling component could comprise one or more suitable sol-gel precursors including for example, metal alkoxides (e.g., titanium ethoxide, zirconium ethoxide, niobium ethoxide, tantalum ethoxide, silicon ethoxide), nitrates, carboxylates, acetylacetonates, chlorides, sulfates (e.g., lithium sulfate, sodium sulfate, potassium sulfate), silicates (e.g., sodium silicate, methyl silicate, tetraethyl orthosilicate

(TEOS)), suitable Click Chemistry reagents, or other suitable precursor. Without limiting the scope of the inventive subject matter, it is especially preferred that the gelling component comprises at least one of an organic and inorganic silicate in an amount of between about 1 -50 % by weight or as suitable to form a gel in the formulation upon reaction with residual copper in the antifouling paint. Furthermore, most preferred gelling components will be water miscible and capable of acting as a precursor for a sol-gel process resulting in the formation of a preferably mesoporous film that clings to antifouling coatings, especially to silicone containing coatings. In some embodiments, the antifouling coating could even form covalent bonds with the gelling component.

[0026] Sol-gel processes generally involve the hydrolysis and condensation of molecular precursors, possibly accelerated by an acid or base catalyst, wherein monomers are converted into a colloidal solution (sol) that acts as the precursor for an integrated network (gel) whose morphologies can range from discrete particles to continuous polymer networks in which polymer chains are interconnected to form a single macroscopic entity by many cross-links. As a sol becomes a gel via gelation, its viscosity can approach infinity and can become immobile when the particle network extends across the entire volume of the liquid. In some aspects of the inventive subject matter, it should be appreciated that the sol-gel process occurring upon application of a antifouling paint remover composition can result in in situ gel formation that advantageously result in a change in viscosity of the antifouling paint remover composition from a pre-application viscosity of less than 20,000 Centipoise (cPs), typically less than 15,000 cPs, more typically less than 10,000 cPs, or even more typically less than 9,000 cPs, to a post- application viscosity of at least 30,000 cPs, more typically at least 50,000 cPs, even more typically at least 100,000 cPs, and most typically at least 250,000 cPs. In especially preferred embodiments, the resulting gels will comprise a mesoporous film that clings to antifouling paint to be lifted and removed from a substrate. In this manner, antifouling paint remover

compositions of the inventive subject matter can be provided in a convenient liquid form and be utilized without the need for external strips (e.g., laminated papers or other strips of material) to assist in adhering the remover to the antifouling paint.

[0027] Thus, and viewed from another perspective, most preferred gelling components will comprise one or more silicates that act as a precursor for a sol-gel process catalyzed by the residual copper in antifouling paint to thereby increase the viscosity of the antifouling paint remover composition by at least 20,000 cPs, more preferably at least 50,000 cPs, even more preferably at least 100,000 cPs, and most preferably at least 250,000 cPs or more. One skilled in the art should appreciate that the increase in viscosity can be at least partially dependent on the type or amount of silicate or solvent component included in the antifouling paint remover composition.

[0028] In still further contemplated aspects of the inventive subject matter, the sol-gel process can be catalyzed by one or more components in a large variety of antifouling marine coatings (e.g., residual copper (copper oxide, Cu ²⁺ )) to advantageously increase the rate of gelling (e.g., hydrolysis and condensation reactions) such that a gel will form and cling to even overhead or vertical substrates before it can drip from the substrate. In some preferred embodiments, the surface to be treated will contain at least 1 ppb, more preferably at least 10 ppb, even more preferably at least 100 ppb, and most preferably at least 1 ppm residual copper. However, it is contemplated that the surface to be treated can comprise any suitable concentration of residual copper (e.g., less than lppb, at least 10 ppm, at least 100 ppm). One should appreciate that while the examples herein are directed towards copper catalyzed sol-gel processes, it is contemplated that antifouling paint remover compositions of the inventive subject matter can undergo sol-gel processes catalyzed by other components of antifouling marine coatings, including one or more components of silicon based coatings, epoxy coatings, ceramic-epoxy coatings, and silicone- rubber coatings. Additionally or alternatively, one or more catalysts (e.g., acid, base) can be used that will assist in breaking the silicon - oxygen bonds of silicate. Such catalyst(s) could be included in the antifouling paint remover composition, added to the composition at or near a time of use, or included in a pre-treatment composition applied to the antifouling paint prior to the antifouling paint remover composition.

[0029] Additionally, it should be recognized that further components may be included into the paint remover to impart one or more desirable characteristics. Among other things, contemplated paint remover formulations may include one or more thickening agents (e.g., carboxymethyl cellulose, ethyl cellulose, propyl cellulose, etc.) in suitable quantities to increase the viscosity of the solution prior to use. Therefore, in most applications, thickeners may be present in an amount of between 0.5 to 25% by weight, between 1 to 20% by weight, or even between 5 to 10%) by weight, and can be used to thicken the antifouling paint remover composition such that it is compatible for use with a specific airless sprayer tip size or range of sizes (e.g., .021-.031). Alternatively, or additionally, contemplated paint removers may also include one or more (typically inorganic) fillers, and especially suitable fillers include bentone, bentonite clay, fumed silica, etc. As before, fillers may be included in the paint remover to any desired proportion, which is typically within a range of between 1 to 30% by weight, more preferably between 3- 15% or 5-10%

[0030] Still further suitable ingredients include emulsifiers, evaporation retarders or humectants and suitable compounds include various ethoxylates, sorbitans, and glycols, typically each or combined in an amount of between 0.2-5%, between 1-4%, or between 2-3% by weight of the remover formulation. Once more, the PHOSITA will be readily able to choose the appropriate compounds and quantities based on the particular substrate, type of antifouling paint, and use. While not limiting to the inventive subject matter, one or more chelating agents may be added, and especially suitable chelators include gluconates, citrates, and/or EDTA, generally in an amount of between 0.5 to 30% by weight, between 1 to 25% by weight, between 5 to 20% by weight, or even between 10 to 15% by weight of the formulation.

[0031] Therefore, without limiting the scope of the inventive subject matter, especially preferred antifouling paint remover compositions can comprise as the solvent component benzyl alcohol or a benzyl alcohol/TBAc mix, typically in an amount from 10-60% (w/w) and more preferably from 25-50% (w/w) in the total composition. Such contemplated antifouling paint remover compositions will comprise as the silicate component inorganic and/or organic silicates, typically in an amount from 1-50% (w/w), and most preferably from 5-20% (w/w) in the total

composition. Inorganic fillers may be included from 1-30% (w/w) and more preferably from 3- 15% (w/w) in the total composition, and emulsifiers and evaporation retarders may be present from 0.2-5% (w/w) and most preferably from 1-4% (w/w) in the total composition. Chelating agents are typically present from 0.5-30% (w/w) and most preferably from 3-1 % (w/w) in the total composition. The balance of the antifouling paint remover compositions is typically water.

[0032] In further preferred aspects of the inventive subject matter, compositions contemplated herein are formulated as a liquid formulation that can be sprayed directly onto horizontal, vertical and overhead substrates having antifouling paint. In a typical example for use, the so formed composition is applied to a marine hull or other apparatus comprising antifouling paint (e.g., with an airless sprayer, brush or roller) to be removed. Once applied, a sol-gel process is catalyzed by residual copper in the antifouling paint to form a polymeric film that is substantially or completely no-sag, and thus clings to the antifouling paint for hours or even days at a time while lifting or removing the antifouling paint from its substrate. The polymeric film can comprise any suitable form, including for example, a solid material composed of a liquid phase entrapped in a three-dimensionally cross-linked network (e.g., a micro, meso or macroporous film).

[0033] While not limiting to the inventive subject matter, it is generally preferred that the composition will be used in well ventilated areas using an airless sprayer with a tip having a suitable size for the viscosity of the liquid composition. It is also contemplated that the composition can be brushed or rolled on the surfaces, especially for smaller areas to be retouched, preferably in an amount such that the color of the antifouling paint is not visible through the remover composition. One skilled in the art should appreciate that the amount of composition necessary to remove antifouling paint from a substrate can be dependent upon various factors, including for example, the amount of residual copper and the number of layers of paint.

[0034] Once the composition has been applied, it can take 1, 3, 5, 10, or even 12 or more hours for the antifouling paint to be lifted from the substrate, at least partially dependent on the number of layers, temperature and type of paint used. While not limiting to the inventive subject matter, for example, it is contemplated that the required dwell time to lift a silicon based antifouling paint could be shorter than that required for an epoxy based antifouling paint. To remove the composition and antifouling paint from the substrate, a pressure washer can be used, preferably at a slight angle, which will generally create two waste streams: a liquid stream and a solid stream. While the compounds making up a liquid or solid stream can vary depending on the composition, type of paint, etc., it is generally contemplated that the liquid stream comprises the composition and wash water, which is preferably inert, fully biodegradable and can be washed down the drain, and the solid stream comprises the paint material, which can be collected at the drainage point and disposed of according to applicable regulations. [0035] Thus, specific compositions and applications of methods of removing antifouling paint have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C .... and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.

[0036] Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints and open-ended ranges should be interpreted to include only commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0037] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

[0038] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the

specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.